Display system, mobile unit, and display panel housing

Abstract

To increase the variety of ways in which images can be viewed. The display system comprises a housing having a viewing section, a first display panel for displaying a first display image, a second display panel for displaying a second display image, and an optical system for forming an image of a first image based on the first display image and a second image based on the second display image, and is positioned so that at least a portion of the first image and at least a portion of the second image overlap when viewed from the inside of the housing through the viewing section.

Description

Technical Field

[0001] The present disclosure relates to a display system, a vehicle, and a display panel housing device.

Background Art

[0002] Conventionally, for example, a display device described in Patent Document 1 is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] A display system according to an aspect of the present disclosure includes a housing having a viewing portion, a first display panel that displays a first display image, a second display panel that displays a second display image, a first image based on the first display image, and an optical system that forms an image of a second image based on the second display image. When looking into the housing from the viewing portion, at least a part of the first image and at least a part of the second image are positioned so as to overlap.

[0005] A display system according to an aspect of the present disclosure includes a housing having a viewing portion, a first display panel that displays a first display image, a second display panel that displays a second display image, and an optical system that forms an image of a first image based on the first display image. When looking into the housing from the viewing portion, at least a part of the first image and at least a part of the second display image are positioned so as to overlap.

[0006] A display panel housing device according to one aspect of the present disclosure is a non-user-mounted display panel housing device comprising: a housing having a viewing section; a first display panel installation section capable of installing a first display panel for displaying a first display image; and a second display panel installation section capable of installing a second display panel for displaying a second display image; and an optical system located inside the housing and forming an image of a first image based on the first display image and a second image based on the second display image, wherein when the inside of the housing is viewed from the viewing section, at least a portion of the first image and at least a portion of the second image overlap.

[0007] A display panel housing device according to one aspect of the present disclosure is a non-user-mounted display panel housing device comprising: a housing having a viewing section; a first display panel installation section capable of installing a first display panel for displaying a first display image; and a second display panel installation section capable of installing a second display panel for displaying a second display image; and an optical system located inside the housing and forming a first image based on the first display image, wherein when the inside of the housing is viewed from the viewing section, at least a portion of the first image and at least a portion of the second display image overlap.

[0008] A display system according to one aspect of the present disclosure is installable within a first housing having a first viewing section and comprises a second housing having a second viewing section, a first display panel located within the second housing and displaying a first display image, a second display panel located within the second housing and displaying a second display image, and an optical system located within the second housing that forms an image of a first image based on the first display image and a second image based on the second display image, wherein when the inside of the second housing is viewed from the second viewing section, at least a portion of the first image and at least a portion of the second image overlap.

[0009] A display system according to one aspect of the present disclosure is installable within a first housing having a first viewing section and comprises a second housing having a second viewing section, a first display panel located within the second housing and displaying a first display image, a second display panel located within the second housing and displaying a second display image, and an optical system located within the second housing and forming a first image based on the first display image, wherein when the inside of the second housing is viewed from the second viewing section, at least a portion of the first image and at least a portion of the second display image overlap.

[0010] A display system according to one aspect of the present disclosure comprises a first housing having a first viewing section, a second housing installed inside the first housing and having a second viewing section, a first display panel located inside the second housing and displaying a first display image, a second display panel located inside the second housing and displaying a second display image, and an optical system located inside the second housing that forms an image of a first image based on the first display image and a second image based on the second display image, wherein when the inside of the second housing is viewed from the second viewing section through the first viewing section, at least a portion of the first image and at least a portion of the second image overlap.

[0011] A display system according to one aspect of the present disclosure comprises a first housing having a first viewing section, a second housing installed inside the first housing and having a second viewing section, a first display panel located inside the second housing and displaying a first display image, a second display panel located inside the second housing and displaying a second display image, and an optical system located inside the second housing and forming a first image based on the first display image, wherein when the inside of the second housing is viewed from the second viewing section through the first viewing section, at least a portion of the first image and at least a portion of the second display image overlap. [Brief explanation of the drawing]

[0012] [Figure 1] This is a cross-sectional view showing the configuration of a display device unit according to Embodiment 1 of this disclosure. [Figure 2] This is a cross-sectional view showing an example of the configuration of a display device. [Figure 3] This is a cross-sectional view showing the configuration of a display device unit according to Embodiment 2 of this disclosure. [Figure 4] This is a cross-sectional view showing the configuration of a first example of a display unit according to Embodiment 3 of this disclosure. [Figure 5] This is a cross-sectional view showing the configuration of a second example of a display unit according to Embodiment 3 of the present disclosure. [Figure 6] This is a cross-sectional view showing the configuration of a display unit according to Embodiment 4 of this disclosure. [Figure 7] This is a cross-sectional view showing the configuration of a first example of a display unit according to Embodiment 5 of the present disclosure. [Figure 8] This is a cross-sectional view showing the configuration of a second example of a display unit according to Embodiment 5 of the present disclosure. [Figure 9] This is a cross-sectional view showing the configuration of a first example of a display unit according to Embodiment 6 of this disclosure. [Figure 10] This is a cross-sectional view showing the configuration of a second example of a display unit according to Embodiment 6 of the present disclosure. [Figure 11] This is a cross-sectional view showing the configuration of a first example of a display unit according to Embodiment 7 of the present disclosure. [Figure 12] This is a cross-sectional view showing the configuration of a second example of a display unit according to Embodiment 7 of this disclosure. [Figure 13] This is a cross-sectional view showing another example of the configuration of a display device. [Figure 14] This is a cross-sectional view showing yet another example of the configuration of a display device. [Figure 15] This is a cross-sectional view showing the configuration of a vehicle according to Embodiment 10 of this disclosure. [Figure 16] This figure shows the internal configuration of the vehicle according to Embodiment 10 of this disclosure. [Figure 17] This is a schematic diagram illustrating the configuration of the display system disclosed herein. [Figure 18] This is a cross-sectional view illustrating the configuration of the display system according to Embodiment 11 of the present disclosure. [Figure 19]It is a cross-sectional view schematically showing the configuration of the display system according to Embodiment 12 of the present disclosure. [Figure 20] It is a cross-sectional view schematically showing the configuration of the display system according to Embodiment 13 of the present disclosure. [Figure 21] It is a cross-sectional view schematically showing the configuration of the display system according to Embodiment 14 of the present disclosure. [Figure 22] It is a cross-sectional view schematically showing the configuration of the display system according to Embodiment 15 of the present disclosure. [Figure 23] It is a schematic diagram schematically showing the configuration of the display system of the present disclosure. [Figure 24] It is a cross-sectional view schematically showing the configuration of the display system according to Embodiment 18 of the present disclosure. [Figure 25] It is a cross-sectional view schematically showing the configuration of the display system according to Embodiment 19 of the present disclosure. [Figure 26] It is a cross-sectional view schematically showing the configuration of the display system according to Embodiment 20 of the present disclosure. [Figure 27] It is a cross-sectional view schematically showing the configuration of the display system according to Embodiment 21 of the present disclosure. [[ID=2[5]] [Figure 28] It is a cross-sectional view schematically showing the configuration of the display system according to Embodiment 22 of the present disclosure.

Mode for Carrying Out the Invention

[0013] It is desired to increase the variations in the way of visual recognition of an image. According to one aspect of the present disclosure, the variations in the way of visual recognition of an image can be increased.

[0014] The mode for carrying out the present disclosure will be described. For the sake of convenience of explanation, members having the same functions as the members described above may be denoted by the same reference numerals, and the description thereof may not be repeated.

[0015] <![CDATA[ ]] 〔Outline of the Display System of the Present Disclosure〕 FIG. 17 is a schematic diagram schematically showing the configurations of the display systems 100A and l00B of the present disclosure.

[0016] The display systems 100A and 100B of this disclosure may be non-wearable devices for users of the display systems 100A and 100B. That is, they may not be worn by the user but may be fixed to the environment. For example, the display systems 100A and 100B may be fixed to a wall, column or ceiling. The display systems 100A and 100B may also be fixed to the interior of a vehicle. Alternatively, the display systems 100A and 100B may be worn by the user. When worn by the user, the display systems 100A and 100B may have a mounting part (not shown) so that the viewing part of the housing 1 is fixed at the position of the user's eyes. In the following description, the user may be referred to as the viewer 102 of the display image displayed by the display systems 100A and 100B, and / or the image formed by the display systems 100A and 100B.

[0017] As shown in Figure 17, the display systems 100A and 100B may include a housing 1, a first display panel 5a, a second display panel 5b, and an optical system 6. The display systems 100A and 100B may also include a controller 14. An example of the specific positional relationship between the first display panel 5a, the second display panel 5b, and the optical system 6 will be described as appropriate in the embodiments described later.

[0018] The housing 1 may have an opening 4. The opening 4 may be located on a part of the wall surface of the housing 1. A viewer 102 may see the display images displayed by the display systems 100A and 100B, and / or the images formed by the display systems 100A and 100B, by looking into the housing 1 through the opening 4. In this case, the image may be formed inside the housing 1, or outside the housing 1 in the direction when looking into the housing 1 from the opening 4 side (-Z axis direction). That is, the image may be formed inside the housing 1, or behind the housing 1. Alternatively, the image may be formed outside the housing 1 in the direction when looking from inside the housing 1 towards the opening 4 side (+Z axis direction). That is, the image may be formed in front of the housing 1. In this case, the viewer 102 can see the image formed in front of the housing 1.

[0019] The display systems 100A and 100B may be provided with a viewing window 52 positioned in the opening 4, allowing the inside of the housing 1 to be viewed from the outside of the housing 1. The viewing window 52 may be positioned to at least partially block the opening 4. The viewing window 52 may be a light-transmitting plate. The viewing window 52 may transmit light emitted from the optical system 6. Examples of materials for the viewing window 52 include light-transmitting glass and resin. The display systems 100A and 100B may also be provided with a touch panel 15 that accepts input operations from a viewer 102. The display systems 100A and 100B may be provided with a touch panel 15 instead of a viewing window 52, ​​or may be provided with a touch panel 15 separately from the viewing window 52. However, the touch panel 15 in this disclosure does not need to have a display panel, but only needs to have the function of an input device that a touch panel has. The opening 4, the viewing window 52, ​​and the touch panel 15 may function as viewing parts of the housing 1.

[0020] In other words, the housing 1 may have a viewing area that allows the inside of the housing 1 to be seen from the outside of the housing 1. The housing 1 may have a member that makes the inside of the housing 1, located in the opening 4, visible from the outside of the housing 1. The viewing area may be a part that allows light emitted from the inside of the housing 1 to be seen from the outside of the housing 1. The viewing area may be, for example, a viewing window 52 or a touch panel 15. Alternatively, the viewing area may be a space where no member such as the opening 4 exists.

[0021] The first display panel 5a may display a first display image. The second display panel 5b may display a second display image. An example of the specific configuration of the first display panel 5a and the second display panel 5b will be described in Embodiment 1.

[0022] The controller 14 is connected to each component of the display systems 100A and 100B and may control each component. The controller 14 may control the display of the first display image by the first display panel 5a and the display of the second display image by the second display panel 5b. If the display systems 100A and 100B are equipped with backlights as described later, the controller 14 may control the backlights.

[0023] The controller 14 may consist of one or more processors. The processors may include general-purpose processors configured to load specific programs and execute specific functions, and dedicated processors specialized for specific processing. The processors may include PLDs (Programmable Logic Devices). The controller 14 may be either a SoC (System-on-a-Chip) or a SiP (System In a Package) in which one or more processors cooperate. The controller 14 includes a memory unit, which may store various information or programs for operating each component of the display systems 100A and 100B. The memory unit may consist of, for example, semiconductor memory. The memory unit may function as the work memory of the controller 14.

[0024] The optical system 6 may form a first image based on a first display image within the field of view of the viewer 102, based on the display light emitted from the first display panel 5a. The optical system 6 may also form a second image based on a second display image within the field of view of the viewer 102, based on the display light emitted from the second display panel 5b. A specific example of the configuration of the optical system 6 will be described as appropriate in the embodiments described later.

[0025] In this disclosure, a display system comprising an optical system 6 that forms a first image and a second image may be referred to as the display system 100A. In the display system 100A, the optical system 6 may be positioned such that at least a portion of the first image and at least a portion of the second image overlap when viewed from the viewing unit into the housing 1. That is, the optical system 6 of the display system 100A may form images of the first image and the second image such that at least a portion of the first image and at least a portion of the second image overlap when viewed from the viewing unit into the housing 1.

[0026] Since the display system 100A can form images of the first and second images as described above, it can increase the variations in how the first and second images are viewed. The display system 100A can increase the variations in how the first and second images are viewed by changing, for example, the way in which the first and second images overlap, and the image formation positions of the first and second images. The image formation positions of the first and second images that are subject to change may be positions in the front-to-back direction (Z-axis direction) of the housing 1. Alternatively, the image formation positions of the first and second images that are subject to change may be positions in a plane perpendicular to the Z-axis (XY plane).

[0027] Furthermore, the display system 100A can be displayed to the viewer 102 such that at least a portion of the first image and at least a portion of the second image overlap. As a result, the viewer 102 can perceive an image with depth.

[0028] On the other hand, a display system equipped with an optical system 6 that forms a first image may be referred to as display system 100B. In display system 100B, the optical system 6 may be positioned such that at least a portion of the first image and at least a portion of the second display image overlap when viewed from the viewing unit into the housing 1. That is, the optical system 6 of display system 100B may form a first image such that at least a portion of the first image and at least a portion of the second display image overlap when viewed from the viewing unit into the housing 1. In addition, the second display panel 5b of display system 100B may display a second display image such that at least a portion of the first image and at least a portion of the second display image overlap when viewed from the viewing unit into the housing 1.

[0029] Since the display system 100B can form images of the first image and the second display image as described above, it can increase the variations in how the first image and the second display image are viewed. The display system 100B can increase the variations in how the first image and the second display image are viewed by changing, for example, the way in which the first image and the second display image overlap, and the imaging position of the first image and the display position of the second display image. The imaging position of the first image and the display position of the second display image that are subject to change may be positions in the front-to-back direction (Z-axis direction) of the housing 1. Alternatively, the imaging position of the first image and the display position of the second display image that are subject to change may be positions in a plane perpendicular to the Z-axis (XY plane).

[0030] Furthermore, the display system 100B can be made to appear to the viewer 102 such that at least a portion of the first image and at least a portion of the second display image overlap. As a result, the viewer 102 can perceive an image with depth.

[0031] The above-mentioned changes may be achieved by modifying the size, shape, and position of the first display panel 5a, the second display panel 5b, and the optical system 6. Alternatively, the above-mentioned changes may be achieved by modifying the structure of the optical components of the optical system 6, such as the thickness of the semi-transparent mirror, reflector, and reflector.

[0032] Furthermore, the size, shape, and imaging position of the first image in the XY plane may be changed by the controller 14 controlling the size, shape, and display position of the first display image on the first display panel 5a, respectively. Similarly, the size, shape, and imaging position of the second image in the XY plane may be changed by the controller 14 controlling the size, shape, and display position of the second display image on the second display panel 5b, respectively.

[0033] The image formed by the optical system 6 may be a virtual image or a real image. That is, the first image may be a virtual image or a real image. Also, the second image may be a virtual image or a real image. If the first image is a virtual image, the second image may be a virtual image or a real image. Also, if the first image is a real image, the second image may be a virtual image or a real image.

[0034] Each embodiment will describe an example of a specific configuration of either the display system 100A or 100B. Embodiments 1 to 10 will describe an example in which the display systems 100A and 100B are implemented as a display unit comprising two display devices.

[0035] [Embodiment 1] Figure 1 is a cross-sectional view showing the configuration of a display unit 101 according to Embodiment 1 of this disclosure. Figure 2 is a cross-sectional view showing an example of the configuration of a display device 2. The display unit 101 according to this embodiment may be an example of a display system 100A.

[0036] The display unit 101 may include a housing 1, a first display device 2a, a second display device 2b, and a reflective polarizing plate 3.

[0037] The housing 1 may have an opening 4. Inside the housing 1, the first display device 2a, the second display device 2b, and the reflective polarizing plate 3 may be located. The opening 4 may be located on a part of the wall surface of the housing 1. A viewer 102 of the display device unit 101 can see the display image 51 of the display device unit 101 by looking into the inside of the housing 1 through the opening 4. In some cases, the viewer 102 may see the display image 51 in front of the housing 1, for example.

[0038] The first display device 2a may have a first display panel 5a and a first optical system 6a. The first display panel 5a may display a first display image 7a. The first optical system 6a may be capable of imaging a first image 9a based on the first display image 7a at a position different from the first display panel 5a by emitting a first polarization 8a based on the first display image 7a. The first image 9a may be referred to as the first image.

[0039] The second display device 2b may have a second display panel 5b and a second optical system 6b. The second display panel 5b may display a second display image 7b. The second optical system 6b may emit a second polarization 8b based on the second display image 7b, thereby imaging a second image 9b based on the second display image 7b at a position different from the second display panel 5b. The second image 9b may be referred to as the second image.

[0040] The first polarization 8a and the second polarization 8b may have complementary polarization characteristics or they may have common polarization characteristics. Of the first polarization 8a and the second polarization 8b, one may be P (horizontal) polarization and the other may be S (vertical) polarization.

[0041] The display unit 101 may be positioned in the opening 4 and include a viewing window 52 that allows the inside of the housing 1 to be viewed from the outside of the housing 1. Examples of materials for the viewing window 52 include translucent glass and resin.

[0042] The display device 2 may have a display panel 5 and an optical system 6. The display device 2 may be a collective term for the first display device 2a and the second display device 2b. The display panel 5 may be a collective term for the first display panel 5a and the second display panel 5b. If the display device unit 101 of this embodiment includes a first optical system 6a and a second optical system 6b, the optical system 6 may be a collective term for the first optical system 6a and the second optical system 6b. The first optical system 6a and the second optical system 6b may be referred to as part of the optical system 6 that forms the first image 9a and the second image 9b. That is, the optical system 6 may be referred to as comprising the first optical system 6a and the second optical system 6b. The display image 7 may be a collective term for the first display image 7a and the second display image 7b. The polarization 8 may be a collective term for the first polarization 8a and the second polarization 8b.

[0043] The display panel 5 may be a liquid crystal panel. The liquid crystal panel may have a known liquid crystal panel configuration. Known liquid crystal panels may be liquid crystal panels such as IPS (In-Plane Switching), FFS (Fringe Field Switching), VA (Vertical Alignment), or ECB (Electrically Controlled Birefringence).

[0044] The display panel 5 is not limited to a liquid crystal panel (transmissive display panel). The display panel 5 may also be a self-emissive display panel that includes self-emissive elements such as light-emitting diodes (LEDs), organic light-emitting diodes (OLEDs), and semiconductor lasers (LDs).

[0045] If the display panel 5 is a liquid crystal panel, the display device unit 101 may include a backlight that is located behind the display panel 5 and illuminates the liquid crystal of the display panel 5. The display device unit 101 may also include a controller 14 that controls at least the display panel 5, or the backlight, based on a video signal.

[0046] The optical system 6 may project the display light emitted from the display panel 5 as an image 9 based on the display image 7 into the field of view of the viewer 102. For the sake of explanation, although the symbols are not shown, image 9 may be a collective term for the first image 9a and the second image 9b. Image 9 may be an example of an image based on the display image 7 that the optical system 6 forms. Image 9 may be a virtual image or a real image.

[0047] The optical system 6 may include a first phase difference plate 53, a semi-transparent mirror 10, a second phase difference plate 54, and a reflective polarizer 55. The first phase difference plate 53, the semi-transparent mirror 10, the second phase difference plate 54, and the reflective polarizer 55 may be positioned in this order in the direction of emission of display light from the display panel 5 (positive direction in the Z-axis direction).

[0048] If the display unit 101 is equipped with a viewing window 52 and the image 9 is a virtual image, the following may be said: The optical system 6 may be able to form an image of the image 9 so that it can be viewed through the viewing window 52. The viewer 102 may be able to view the image 9 by looking into the viewing window 52. The viewer 102 cannot view the image 9 without the viewing window 52.

[0049] If the display unit 101 does not have a viewing window 52 and the image 9 is a virtual image, the optical system 6 only needs to be able to form an image of the image 9 so that it can be viewed through the aperture 4.

[0050] The first phase difference plate 53 may be positioned opposite the display panel 5, or it may be positioned at a distance from the display panel 5. The second phase difference plate 54 may be positioned at a distance from the first phase difference plate 53 in the direction of emission of display light from the display panel 5. The first phase difference plate 53 and the second phase difference plate 54 may be quarter-wave plates. The first phase difference plate 53 and the second phase difference plate 54 may give a phase difference of 1 / 4 wavelength to the polarization plane (polarization plane in the direction of electric field vibration) of the incident light. This makes it possible to reflect a portion of the display light emitted from the display panel 5 with the reflective polarizer plate 55 and have it incident on the semi-transparent mirror 10. The positional relationship between the first phase difference plate 53 and the second phase difference plate 54 may be defined such that when the first phase difference plate 53 and the second phase difference plate 54 are viewed along the Z-axis direction, the lagging axis of the second phase difference plate 54 is perpendicular to the lagging axis of the first phase difference plate 53. Furthermore, the positional relationship between the first phase difference plate 53 and the second phase difference plate 54 may be defined such that, when the first phase difference plate 53 and the second phase difference plate 54 are viewed along the Z-axis direction, the retard axis of the second phase difference plate 54 and the retard axis of the first phase difference plate 53 are parallel.

[0051] The first phase difference plate 53 and the second phase difference plate 54 only need to provide the necessary phase difference to the light transmitted through them so that the light transmitted through them is reflected by the reflective polarizer 55. As long as this can be achieved, the first phase difference plate 53 and / or the second phase difference plate 54 may be other wave plates or combinations thereof, rather than quarter-wave plates. In this disclosure, the case where the first phase difference plate 53 and the second phase difference plate 54 are quarter-wave plates will be explained as an example. Furthermore, the first phase difference plate 53 and the second phase difference plate 54 may be film-like members.

[0052] The second phase difference plate 54 only needs to provide the necessary phase difference to the light that has passed through the second phase difference plate 54, so that the light that has been reflected by the reflective polarizing plate 55 and passed through the second phase difference plate 54 passes through the reflective polarizing plate 55 again when it reaches the reflective polarizing plate 55. As long as this can be achieved, the second phase difference plate 54 may be a wave plate other than a quarter wave plate.

[0053] The first phase difference plate 53 may be integrated with the display panel 5. "Integration" may mean that the two members are arranged in contact with each other, or that the two members are joined to each other by an optically transparent adhesive such as OCR (Optical Clear Resin) or OCA (Optical Clear Adhesive). However, the first phase difference plate 53 may be located away from the display panel 5 in the direction of emission of display light from the display panel 5.

[0054] The semi-transparent mirror 10 may be positioned between the first phase difference plate 53 and the second phase difference plate 54. The semi-transparent mirror 10 may transmit a portion of the incident light (e.g., approximately 50%) and reflect the remainder (e.g., approximately 50%). However, the transmittance and reflectance of the light incident on the semi-transparent mirror 10 are not limited to 50%. The semi-transparent mirror 10 may have a function to collect or focus light. Specifically, the semi-transparent mirror 10 may have a function to collect or focus light that has been incident on and reflected by the semi-transparent mirror 10. The semi-transparent mirror 10 may reflect a portion of the display light reflected by the reflective polarizer 55 and direct it into the eyes of the viewer 102. This makes it possible for the viewer 102 to view the image 9. The semi-transparent mirror 10 may be a concave mirror having a concave reflective surface 56. The reflective surface 56 of the semi-transparent mirror 10 may be located on the side of the second phase difference plate 54. The semi-transparent mirror 10 may include a spherical, aspherical, or free-form shape in at least a portion of its reflective surface 56. The semi-transparent mirror 10 may focus or concentrate light more effectively than other components of the optical system 6. In other words, the semi-transparent mirror 10 may have a larger degree of focusing, convergence, or an index expressed as the reciprocal of the focal length than other components of the optical system 6. The reflective surface 56 of the semi-transparent mirror 10 may have a greater curvature than other components of the optical system 6. The optical system 6 may have only the semi-transparent mirror 10 as a component with a focusing or converging function. The semi-transparent mirror 10 may also include a holographic optical element (HOE), or its surface shape may have a Fresnel shape.

[0055] The semi-transparent mirror 10 may be composed of, for example, a substrate and a semi-transparent reflective layer located on the surface of the substrate. The substrate may have a transmittance of 100% or close to 100% for light in the visible light band. The substrate may be made of a resin material, a glass material, etc. The resin material may be acrylic resin, polycarbonate resin, etc. The semi-transparent reflective layer may be a thin metal film. The thin metal film may be made of a metal material such as aluminum or chromium. The semi-transparent reflective layer is not limited to a thin metal film, but may also be a dielectric multilayer film, etc. The semi-transparent mirror 10 may be configured to reflect light with the semi-transparent reflective layer. The semi-transparent reflective layer may be formed on the surface of the substrate on the side of the second phase difference plate 54.

[0056] The reflective polarizer 55 may be positioned on the opposite side of the first phase difference plate 53 from the second phase difference plate 54. The reflective polarizer 55 may be positioned downstream of the second phase difference plate 54 in the direction of emission of display light from the display panel 5. The reflective polarizer 55 may transmit a portion of the incident light and reflect the remainder. The reflective polarizer 55 may reflect light having the same polarization characteristics as the display light from the display panel 5 and transmit light having polarization characteristics opposite to those of the display light from the display panel 5. Alternatively, the reflective polarizer 55 may reflect light having polarization characteristics opposite to those of the display light from the display panel 5 and transmit light having the same polarization characteristics as the display light from the display panel 5. The display light from the display panel 5 may be either P-polarized or S-polarized, and the light having polarization characteristics opposite to those of the display light from the display panel 5 may be the other of P-polarized or S-polarized. This makes it possible for the viewer 102 to view the image 9. The reflective polarizing plate 55 may be integrated with the second phase difference plate 54.

[0057] The reflective polarizer 55 may have the function of diverging the light that is incident on the semi-transparent mirror 10 and reflected. Alternatively, the reflective polarizer 55 may have the function of focusing or converging the light that is incident on the semi-transparent mirror 10 and reflected. The reflective polarizer 55 may be flat, have a concave shape on the display panel 5 side, or have a convex shape on the display panel 5 side. Furthermore, the reflective polarizer 55 may include a holographic optical element, or its surface shape may have a Fresnel shape.

[0058] The reflective polarizer 55 may be a wire grid polarizer comprising, for example, a substrate and a plurality of metal nanowires (also called a metal nanowire grid) located on the surface of the substrate. The substrate may have a transmittance of 100% or close to 100% for light in the visible light band. The substrate may be made of a resin material, a glass material, etc. The metal nanowires may be made of a metal material such as aluminum, chromium, or titanium oxide. The metal nanowires may be arranged along one direction. The reflective polarizer 55 can transmit light components vibrating in a direction perpendicular to the grid and can reflect light components vibrating in a direction parallel to the grid.

[0059] The display panel 5 may emit linearly polarized light (A) L1 as display light. The linearly polarized light (A) L1 emitted from the display panel 5 may pass through the first phase difference plate 53 and be converted into first circularly polarized light C1. A portion (for example, approximately 50%) of the first circularly polarized light C1 that has passed through the first phase difference plate 53 may pass through the semitransparent mirror 10. The first circularly polarized light C1 that has passed through the semitransparent mirror 10 may pass through the second phase difference plate 54 and be converted into linearly polarized light (B) L2 whose polarization characteristics are parallel to those of linearly polarized light (A) L1. The linearly polarized light (B) L2 may be incident on the reflective polarizer 55. The linearly polarized light (B) L2 incident on the reflective polarizer 55 may be reflected by the reflective polarizer 55 and converted into linearly polarized light (C) L3 whose polarization characteristics are parallel to those of linearly polarized light (A) L1. Linearly polarized light (C) L3 may pass through the second phase difference plate 54 and be converted to second circularly polarized light C2. A portion of the second circularly polarized light C2 that has passed through the second phase difference plate 54 (for example, approximately 50%) may be reflected by the semitransparent mirror 10 and converted to third circularly polarized light C3. The third circularly polarized light C3 may pass through the second phase difference plate 54 and be converted to linearly polarized light (D) L4 whose polarization characteristics are orthogonal to linearly polarized light (A) L1. Linearly polarized light (D) L4 may pass through the reflective polarizer 55 and be emitted to the outside as polarized light 8. The amount of light (luminance) emitted from the display device 2 may be, for example, approximately 25% of the amount of light (luminance) of the display light emitted from the display panel 5.

[0060] Depending on the setting of the axis of the first phase difference plate 53 and / or the axis of the second phase difference plate 54, the polarization characteristics of the linearly polarized light (A) L1 (display image 7) emitted from the display panel 5 and the polarization characteristics of the linearly polarized light (D) L4 (polarized light 8) reflected by the semi-transparent mirror 10 and emitted from the display device 2 can be made different or the same.

[0061] For example, the reflective polarizer 55 may be configured to reflect polarized light having a polarization axis parallel to the polarization axis of the display light and transmit polarized light having a polarization axis perpendicular to the polarization axis of the display light. In this case, the positional relationship between the first phase difference plate 53 and the second phase difference plate 54 may be defined such that when the first phase difference plate 53 and the second phase difference plate 54 are viewed along the Z-axis direction, the lagging axis of the second phase difference plate 54 is perpendicular to the lagging axis of the first phase difference plate 53. Alternatively, for example, the reflective polarizer 55 may be configured to reflect polarized light having a polarization axis perpendicular to the polarization axis of the display light and transmit polarized light having a polarization axis parallel to the polarization axis of the display light. In this case, the positional relationship between the first phase difference plate 53 and the second phase difference plate 54 may be defined such that when the first phase difference plate 53 and the second phase difference plate 54 are viewed along the Z-axis direction, the lagging axis of the second phase difference plate 54 is parallel to the lagging axis of the first phase difference plate 53.

[0062] The reflective polarizer 3 may reflect the first polarized light 8a emitted from the first display device 2a and guide it to the aperture 4. The display device unit 101 may emit the first polarized light 8a reflected by the reflective polarizer 3 and the second polarized light 8b emitted from the second display device 2b from the aperture 4. In other words, the reflective polarizer 3 may function as a mirror that reflects the first image 9a. A mirror has the function of projecting an object as a virtual image, and therefore may be referred to as an image-forming component. For this reason, the reflective polarizer 3 may also be referred to as part of the optical system 6 that forms the first image 9a.

[0063] According to the display device unit 101, by reflecting the first polarized light 8a emitted from the first display device 2a with the reflective polarizing plate 3, it is possible to easily adjust the optical path of the light emitted from the first display device 2a and the second display device 2b without having to bring the positions of the first display device 2a and the second display device 2b extremely close together. Therefore, using the first image 9a formed from the first display image 7a and the second image 9b formed from the second display image 7b, the viewer 102 can be made to perceive depth in relation to the image 9. In order to make the viewer 102 perceive depth in relation to the image 9, the distance between the aperture 4 and the first image 9a and the distance between the aperture 4 and the second image 9b may be different.

[0064] As described above, the display unit 101 can increase the variations in how the image 9, which is projected at a different position from the display panel 5 based on the display image 7 displayed by the display panel 5, can be viewed.

[0065] The reflective polarizing plate 3 may transmit the second polarized light 8b emitted from the second display device 2b. As a result, the optical paths of the light emitted from the first display device 2a and the second display device 2b may overlap or be located close to the viewer 102 side of the reflective polarizing plate 3, either parallel or at a small angle. Therefore, the first image 9a and the second image 9b can be superimposed, allowing the viewer 102 to perceive a three-dimensional display image 51. In order to allow the viewer 102 to perceive a three-dimensional display image 51, the distance between the aperture 4 and the first image 9a and the distance between the aperture 4 and the second image 9b may be different.

[0066] The normal direction of the first display panel 5a and the normal direction of the second display panel 5b may be orthogonal. The optical path 11b of the second polarized light 8b emitted from the second display device 2b and the optical path 11a of the first polarized light 8a emitted from the first display device 2a on the side of the first display device 2a that is closer to the first display device 2a than the reflective polarizer 3 may be orthogonal. This allows for a wider positioning space for the first display device 2a and the second display device 2b, thus providing greater design flexibility.

[0067] The angle θb between the optical path 11b of the second polarized light 8b emitted from the second display device 2b and the reflective polarizer 3 may be 45°, and the angle θa between the optical path 11a of the first polarized light 8a emitted from the first display device 2a and the reflective polarizer 3 on the side of the first display device 2a that is closer to the reflective polarizer 3 may also be 45°. This allows the optical paths 11a and 11b to be theoretically parallel on the side of the optical path 11a and 11b that is closer to the viewer 102 than the reflective polarizer 3. Therefore, it may be easy to superimpose the first image 9a and the second image 9b to allow the viewer 102 to perceive a three-dimensional display image 51.

[0068] The reflection position of the first polarized light 8a emitted from the first display device 2a on the reflective polarizing plate 3 may be the first portion 12 of the reflective polarizing plate 3, and the transmission position of the second polarized light 8b emitted from the second display device 2b on the reflective polarizing plate 3 may also be the first portion 12 of the reflective polarizing plate 3. This makes it easy to superimpose the first image 9a and the second image 9b to allow the viewer 102 to perceive a three-dimensional display image 51.

[0069] As described in the overview of the display system of this disclosure, the optical system 6 may image the first image 9a and the second image 9b such that, when viewed from the aperture 4 into the housing 1, at least a portion of the first image 9a and at least a portion of the second image 9b overlap. That is, when viewed from the aperture 4 into the housing 1, the first image 9a and the second image 9b may almost overlap, or a portion of the first image 9a and a portion of the second image 9b may overlap.

[0070] Furthermore, as shown in Figure 1, the imaging positions of the first image 9a and the second image 9b may be different in the direction viewed from the opening 4 into the interior of the housing 1, i.e., in the front-to-back direction of the housing 1. However, these two imaging positions may be the same in the front-to-back direction of the housing 1.

[0071] Furthermore, as described above, the optical system 6 may form a virtual or real image as the image 9. In the example in Figure 2, the optical path length of the light emitted from the display panel 5, passing through the semi-transparent mirror 10, reflected by the reflective polarizer 55, and reaching the semi-transparent mirror 10 may be smaller than the focal length of the semi-transparent mirror 10. In other words, the focal length of the semi-transparent mirror 10 may be longer than the optical path length. In this case, the optical system 6 can form a virtual image, allowing the viewer 102 to perceive the virtual image. Alternatively, for example, the optical path length may be larger than the focal length of the semi-transparent mirror 10. In other words, the focal length of the semi-transparent mirror 10 may be shorter than the optical path length. In this case, the optical system 6 can form a real image, allowing the viewer 102 to perceive the real image. The optical path length may also be referred to as the optical path length from the display panel 5 to the point where the light emitted from the display panel 5 passes through the semi-transparent mirror 10 and re-enters the semi-transparent mirror 10.

[0072] [Embodiment 2] Figure 3 is a cross-sectional view showing the configuration of a display device unit 101 according to Embodiment 2 of the present disclosure. The display device unit 101 according to this embodiment may be an example of a display system 100A. That is, the optical system 6 may include a first optical system 6a and a second optical system 6b, and may form images of a first image 9a and a second image 9b.

[0073] The position of the reflective polarizer 3 may be different from the position on the optical path 11b of the second polarized light 8b emitted from the second display device 2b. This makes it possible to reduce the loss of the second polarized light 8b.

[0074] Furthermore, in the display device unit 101 according to this embodiment, the first image 9a and the second image 9b may be imaged such that at least a part of the first image 9a and at least a part of the second image 9b overlap when the inside of the housing 1 is viewed from the opening 4. That is, even if the positional relationship between the first display device 2a, the second display device 2b and the reflective polarizer 3 is defined so that the second polarized light 8b does not pass through the reflective polarizer 3, the first image 9a and the second image 9b may be imaged such that the above-mentioned overlap occurs.

[0075] Furthermore, as shown in Figure 3, the imaging positions of the first image 9a and the second image 9b may be different in the front-to-back direction of the housing 1. However, these two imaging positions may be the same in the front-to-back direction of the housing 1.

[0076] [Embodiment 3] Figure 4 is a cross-sectional view showing the configuration of a first example of a display unit 101 according to Embodiment 3 of the present disclosure. Figure 5 is a cross-sectional view showing the configuration of a second example of a display unit 101 according to Embodiment 3 of the present disclosure. The display unit 101 according to this embodiment may be an example of a display system 100A. That is, the optical system 6 may include a first optical system 6a and a second optical system 6b, and may form images of a first image 9a and a second image 9b.

[0077] The angle θb between the optical path 11b of the second polarized light 8b emitted from the second display device 2b and the reflective polarizer 3 may be different from the angle θa between the optical path 11a of the first polarized light 8a emitted from the first display device 2a and the reflective polarizer 3 on the side of the first display device 2a that is closer to the reflective polarizer 3. This makes it easy to intentionally shift the first image 9a and the second image 9b while giving the viewer 102 a sense of depth to the displayed image 51.

[0078] In Figures 4 and 5, the first image 9a and the second image 9b are shown not overlapping when viewed from the opening 4 into the housing 1. However, in the display device unit 101 according to this embodiment, the first image 9a and the second image 9b may be imaged such that at least a portion of the first image 9a and at least a portion of the second image 9b overlap when viewed from the opening 4 into the housing 1. That is, even when the reflective polarizing plate 3 is arranged such that angles θa and θb are angles other than 45°, the first image 9a and the second image 9b may be imaged such that the above-mentioned overlap occurs by, for example, adjusting the size of angles θa and θb.

[0079] Furthermore, as shown in Figures 4 and 5, the imaging positions of the first image 9a and the second image 9b may be different in the front-to-back direction of the housing 1. However, these two imaging positions may be the same in the front-to-back direction of the housing 1.

[0080] [Embodiment 4] Figure 6 is a cross-sectional view showing the configuration of a display device unit 101 according to Embodiment 4 of the present disclosure. The display device unit 101 according to this embodiment may be an example of a display system 100A. That is, the optical system 6 may include a first optical system 6a and a second optical system 6b, and may form images of a first image 9a and a second image 9b.

[0081] The reflection position of the first polarized light 8a emitted from the first display device 2a on the reflective polarizing plate 3 is the first portion 12 of the reflective polarizing plate 3, and the transmission position of the second polarized light 8b emitted from the second display device 2b on the reflective polarizing plate 3 may be a second portion 13, which is different from the first portion 12 of the reflective polarizing plate 3. This makes it easy to intentionally shift the first image 9a and the second image 9b while giving the viewer 102 a sense of depth to the displayed image 51.

[0082] Furthermore, in the display device unit 101 according to this embodiment, the first image 9a and the second image 9b may be imaged such that at least a part of the first image 9a and at least a part of the second image 9b overlap when the inside of the housing 1 is viewed from the opening 4. That is, even if the positional relationship between the first display device 2a, the second display device 2b and the reflective polarizing plate 3 is defined such that the transmission positions of the first polarization 8a and the second polarization 8b in the reflective polarizing plate 3 are different, the first image 9a and the second image 9b may be imaged such that the above-mentioned overlap occurs.

[0083] Furthermore, as shown in Figure 6, the imaging positions of the first image 9a and the second image 9b may be different in the front-to-back direction of the housing 1. However, these two imaging positions may be the same in the front-to-back direction of the housing 1.

[0084] [Embodiment 5] Figure 7 is a cross-sectional view showing the configuration of a first example of a display unit 101 according to Embodiment 5 of this disclosure. Figure 8 is a cross-sectional view showing the configuration of a second example of a display unit 101 according to Embodiment 5 of this disclosure. Figures 7 and 8 show images of the first semi-transparent mirror 10a and the second semi-transparent mirror 10b. The aforementioned semi-transparent mirror 10 may be a collective term for the first semi-transparent mirror 10a and the second semi-transparent mirror 10b. The display unit 101 according to this embodiment may be an example of a display system 100A. That is, the optical system 6 may include a first optical system 6a and a second optical system 6b, and may form images of a first image 9a and a second image 9b.

[0085] As shown in Figure 7, the first optical system 6a has a first semi-transparent mirror 10a, and the upright direction Z5a of the first display panel 5a and the upright direction Z10a of the first semi-transparent mirror 10a may be different. This allows the first image 9a to be intentionally tilted, so that the viewer 102 can perceive depth in relation to the displayed image 51.

[0086] The upright direction Z5a may be a direction along the display surface of the first display panel 5a. The upright direction Z10a may be a direction along a straight line passing through both ends of the first semitransparent mirror 10a in a cross-sectional view of the first semitransparent mirror 10a. The tilt of the first image 9a may correspond to the angle θZa made by the upright direction Z5a and the upright direction Z10a.

[0087] The second optical system 6b has a second semi-transparent mirror 10b, and the upright direction Z5b of the second display panel 5b and the upright direction Z10b of the second semi-transparent mirror 10b may be different. This allows the second image 9b to be intentionally tilted, so that the viewer 102 can perceive depth in relation to the displayed image 51.

[0088] The upright direction Z5b may be the direction along the display surface of the second display panel 5b. The upright direction Z10b may be the direction along the straight line passing through both ends of the second semitransparent mirror 10b in a cross-sectional view of the second semitransparent mirror 10b. The tilt of the second image 9b may correspond to the angle θZb made by the upright direction Z5b and the upright direction Z10b.

[0089] Figure 8 shows an example where the upright directions Z5a and Z10a are different, and the upright directions Z5b and Z10b are different. It is also possible for the upright directions Z5a and Z10a to be the same, and for the upright directions Z5b and Z10b to be different.

[0090] Furthermore, in the display device unit 101 according to this embodiment, the first image 9a and the second image 9b may be imaged such that at least a portion of the first image 9a and at least a portion of the second image 9b overlap when the inside of the housing 1 is viewed from the opening 4. In other words, even if the inclination of the semitransparent mirror 10 with respect to the display panel 5 is appropriately changed, the first image 9a and the second image 9b may be imaged in such a way that the above-mentioned overlap occurs.

[0091] Furthermore, as shown in Figures 7 and 8, the imaging positions of the first image 9a and the second image 9b may be different in the front-to-back direction of the housing 1. However, these two imaging positions may be the same in the front-to-back direction of the housing 1.

[0092] [Embodiment 6] Figure 9 is a cross-sectional view showing the configuration of a first example of a display unit 101 according to Embodiment 6 of the present disclosure. Figure 10 is a cross-sectional view showing the configuration of a second example of a display unit 101 according to Embodiment 6 of the present disclosure.

[0093] As shown in Figure 9, the second display device 2b does not necessarily have a second optical system 6b that can image a second image 9b based on the second display image 7b at a position different from the second display panel 5b by emitting a second polarization 8b based on the second display image 7b. The second display device 2b may have a second display panel 5b that displays the second display image 7b and emits a second polarization 8b based on the second display image 7b. In this case as well, the configuration and function of the housing 1, the first display device 2a, and the reflective polarizer 3, and the fact that the display device unit 101 emits the first polarization 8a reflected by the reflective polarizer 3 and the second polarization 8b emitted from the second display device 2b from the aperture 4 remain unchanged.

[0094] This allows the viewer 102 to perceive depth in image 9 using the first image 9a and the second image 7b formed from the first display image 7a.

[0095] Thus, the display unit 101 shown in Figure 9 may be an example of the display system 100B. That is, the optical system 6 may include a first optical system 6a and form an image of the first image 9a. In the display unit 101 shown in Figure 9, the first image 9a and the second image 9b may be formed such that at least a part of the first image 9a and at least a part of the second display image 7b overlap when the inside of the housing 1 is viewed from the opening 4.

[0096] Furthermore, as shown in Figure 9, the imaging position of the first image 9a and the display position of the second display image 7b may be different in the front-to-back direction of the housing 1. However, the imaging position of the first image 9a and the display position of the second display image 7b may be the same in the front-to-back direction of the housing 1. In this case, the imaging position of the first image 9a may be the position of the display surface of the second display panel 5b.

[0097] As shown in Figure 10, the first display device 2a does not necessarily have a first optical system 6a that can image a first image 9a based on the first display image 7a at a position different from the first display panel 5a by emitting a first polarization 8a based on the first display image 7a. The first display device 2a may have a first display panel 5a that displays the first display image 7a and emits a first polarization 8a based on the first display image 7a. In this case as well, the configuration and function of the housing 1, the second display device 2b, and the reflective polarizer 3, and the fact that the display device unit 101 emits the first polarization 8a reflected by the reflective polarizer 3 and the second polarization 8b emitted from the second display device 2b from the aperture 4 remain unchanged.

[0098] This allows the viewer 102 to perceive depth in image 9 using the second image 9b formed from the first display image 7a and the second display image 7b.

[0099] Thus, the display unit 101 shown in Figure 10 may be an example of the display system 100A. That is, the optical system 6 may include a second optical system 6b that forms a second image 9b. Furthermore, the reflective polarizing plate 3 according to this embodiment may function as a mirror that reflects the first display image 7a displayed by the first display device 2a towards the aperture 4. As described above, since a mirror has the function of projecting an object as a virtual image, the reflective polarizing plate 3 that reflects the first display image 7a towards the aperture 4 may also be said to form a first image 9a based on the first display image 7a. Therefore, the display unit 101 shown in Figure 10 may include an optical system 6 that forms a first image 9a and a second image 9b. The display unit 101 shown in Figure 10 may form images of the first image 9a and the second image 9b such that at least a part of the first image 9a and at least a part of the second image 9a overlap when the inside of the housing 1 is viewed from the aperture 4.

[0100] Furthermore, as shown in Figure 10, in the front-to-back direction of the housing 1, the imaging position of the first image 9a, which is formed by the reflection of the first display image 7a by the reflective polarizing plate 3, and the imaging position of the second image 9b may be different or the same.

[0101] [Embodiment 7] Figure 11 is a cross-sectional view showing the configuration of a first example of a display unit 101 according to Embodiment 7 of the present disclosure. Figure 12 is a cross-sectional view showing the configuration of a second example of a display unit 101 according to Embodiment 7 of the present disclosure. The display unit 101 according to this embodiment may be an example of a display system 100A. That is, the optical system 6 may include a first optical system 6a and a second optical system 6b, and may form images of a first image 9a and a second image 9b.

[0102] In the display unit 101, the first image 9a and the second image 9b may be located along the same plane PLN.

[0103] In the first example, when the inside of the housing 1 is viewed from the opening 4, at least a portion of the first image 9a and at least a portion of the second image 9b are superimposed, and the content 9ac of the first image 9a and the content 9bc of the second image 9b may be the same in this superimposed portion. This results in a display image 51 with high brightness of the content.

[0104] In the second example, the first image 9a and the second image 9b may be positioned offset from each other. This allows for a single display image 51 that is larger than both the first image 9a and the second image 9b, with the portion belonging to the first image 9a having the resolution of the first image 9a and the portion belonging to the second image 9b having the resolution of the second image 9b. In other words, the resolution of the display image 51 relative to its size can be increased, thus ensuring high resolution of the display image 51.

[0105] The optical system 6 according to this embodiment does not have to image the first image 9a and the second image 9b so that they are located along the same plane PLN. That is, the optical system 6 according to this embodiment may image the first image 9a and the second image 9b so that they are located in different XY planes. That is, the optical system 6 according to this embodiment may image the first image 9a and the second image 9b so that the imaging positions of the first image 9a and the second image 9b are different in the front-to-back direction of the housing 1.

[0106] [Embodiment 8] Figure 13 is a cross-sectional view showing another example of the configuration of the display device 2.

[0107] The optical system 6 may include a first semi-transparent mirror 10X, a first phase difference plate 53, a second semi-transparent mirror 10Y, a second phase difference plate 54, and a polarizing plate 57. The first semi-transparent mirror 10X, the first phase difference plate 53, the second semi-transparent mirror 10Y, the second phase difference plate 54, and the polarizing plate 57 may be positioned in this order in the direction of emission of display light from the display panel 5 (positive direction in the Z-axis direction).

[0108] The first phase difference plate 53 may be located on the opposite side of the display panel 5 from the first semi-transparent mirror 10X. The first phase difference plate 53 may be located away from the display panel 5 in the direction of emission of display light from the display panel 5. The second phase difference plate 54 may be located away from the first phase difference plate 53 in the direction of emission of display light. The first phase difference plate 53 and the second phase difference plate 54 may be quarter-wave plates. The positional relationship between the first phase difference plate 53 and the second phase difference plate 54 may be defined such that, when viewed along the Z-axis direction, the lagging axis of the second phase difference plate 54 is perpendicular to the lagging axis of the first phase difference plate 53. Furthermore, the positional relationship between the first phase difference plate 53 and the second phase difference plate 54 may be defined such that, when the first phase difference plate 53 and the second phase difference plate 54 are viewed along the Z-axis direction, the retard axis of the second phase difference plate 54 and the retard axis of the first phase difference plate 53 are parallel.

[0109] The first semi-transparent mirror 10X may be positioned between the display panel 5 and the first phase difference plate 53. The first semi-transparent mirror 10X may transmit a portion of the incident light and reflect the remainder. In this embodiment, the first semi-transparent mirror 10X may be configured to transmit polarized light having a polarization axis parallel to the polarization axis of the display light and to reflect polarized light having a polarization axis perpendicular to the polarization axis of the display light. The first semi-transparent mirror 10X may have a function to collect or focus light. Specifically, the first semi-transparent mirror 10X may have a function to collect or focus light that has been incident on and reflected by the first semi-transparent mirror 10X. The first semi-transparent mirror 10X may be a concave mirror having a concave reflective surface 58. The reflective surface 58 of the first semi-transparent mirror 10X may be located on the first phase difference plate 53 side. The first semi-transparent mirror 10X may collect or focus light more effectively than other members of the optical system 6. In other words, the first semi-transparent mirror 10X may have a larger indicator, such as a greater degree of light gathering, a greater degree of focus, or an indicator expressed as the reciprocal of the focal length, than other components of the optical system 6. The reflective surface 58 of the first semi-transparent mirror 10X may have a greater curvature than other components of the optical system 6. The optical system 6 may have only the first semi-transparent mirror 10X as a component with a light-gathering or focusing function. The first semi-transparent mirror 10X may include a spherical shape, an aspherical shape, or a free-form shape in at least a portion of its reflective surface 58. Furthermore, the first semi-transparent mirror 10X may be composed of a holographic optical element, or its surface shape may have a Fresnel shape.

[0110] The first semi-transparent mirror 10X may be composed of, for example, a substrate and a plurality of metal nanowires (metal nanowire grids) located on the surface of the substrate. The substrate may have a transmittance of 100% or close to 100% for light in the visible light band. The substrate may be made of a resin material, a glass material, etc. The resin material may be acrylic resin, polycarbonate resin, etc. The metal nanowires may be made of a metal material such as aluminum, chromium, or titanium oxide. The metal nanowires may be arranged along one direction. The first semi-transparent mirror 10X can transmit light components vibrating in a direction perpendicular to the grid and reflect light components vibrating in a direction parallel to the grid. The metal nanowire grid may be formed on the surface of the substrate on the side of the first phase difference plate 53. In this example, the metal nanowire grid is used to impart a reflective polarization function to the first semi-transparent mirror 10X, but the first semi-transparent mirror 10X may be used as a simple half-mirror and a separate reflective polarizer may be provided.

[0111] The second semi-transparent mirror 10Y may be positioned between the first phase difference plate 53 and the second phase difference plate 54. The second semi-transparent mirror 10Y may transmit a portion of the incident light (e.g., approximately 50%) and reflect the remainder (e.g., approximately 50%). However, the transmittance and reflectance of the light incident on the second semi-transparent mirror 10Y are not limited to 50%. The second semi-transparent mirror 10Y may be positioned on the opposite side of the first semi-transparent mirror 10X from the first phase difference plate 53, and more specifically, the reflective surface 59 may be positioned on the side of the first phase difference plate 53. The second semi-transparent mirror 10Y may be a plane mirror. In this case, the second semi-transparent mirror 10Y may also be called a plane half-mirror.

[0112] The second semi-transparent mirror 10Y may have a function to diverge the light that is incident on and reflected by the second semi-transparent mirror 10Y. The second semi-transparent mirror 10Y may have a convex reflective surface 59, and the reflective surface 59 may be located on the side of the first phase difference plate 53. The second semi-transparent mirror 10Y may also be called a convex half mirror. The second semi-transparent mirror 10Y may have a function to collect or focus the light that is incident on and reflected by the second semi-transparent mirror 10Y. Specifically, the second semi-transparent mirror 10Y may have a concave shape located on the side of the display panel 5. Furthermore, the second semi-transparent mirror 10Y may be composed of a holographic optical element, or its surface shape may have a Fresnel shape. The second semi-transparent mirror 10Y may be integrated with the first phase difference plate 53 and / or the second phase difference plate 54.

[0113] The second semi-transparent mirror 10Y may be composed of, for example, a substrate and a semi-transparent reflective layer located on the surface of the substrate. The substrate may have a transmittance of 100% or close to 100% for light in the visible light band. The substrate may be made of inorganic glass, resin material, etc. The resin material may be acrylic resin, polycarbonate resin, etc. The semi-transparent reflective layer may be a thin metal film. The thin metal film may be made of a metal material such as aluminum or chromium. The semi-transparent reflective layer is not limited to a thin metal film, but may also be a dielectric multilayer film, etc.

[0114] The polarizing plate 57 may be positioned on the opposite side of the second semitransparent mirror 10Y from the second phase difference plate 54. The polarizing plate 57 may be positioned downstream of the second phase difference plate 54 in the direction of emission of display light from the display panel 5. The polarizing plate 57 may transmit a portion of the incident light and absorb or reflect the remainder. The polarizing plate 57 may be configured to absorb or reflect polarized light having a polarization axis parallel to the polarization axis of the display light, and to transmit polarized light having a polarization axis perpendicular to the polarization axis of the display light. In this case, the positional relationship between the first phase difference plate 53 and the second phase difference plate 54 may be defined such that, when the first phase difference plate 53 and the second phase difference plate 54 are viewed along the Z-axis direction, the lagging axis of the second phase difference plate 54 is perpendicular to the lagging axis of the first phase difference plate 53. Alternatively, the polarizing plate 57 may be configured to absorb or reflect polarized light having a polarization axis perpendicular to the polarization axis of the display light, and to transmit polarized light having a polarization axis parallel to the polarization axis of the display light. In this case, the positional relationship between the first phase difference plate 53 and the second phase difference plate 54 may be defined such that, when the first phase difference plate 53 and the second phase difference plate 54 are viewed along the Z-axis direction, the lagging axis of the second phase difference plate 54 and the lagging axis of the first phase difference plate 53 are parallel. Furthermore, the polarizing plate 57 may be integrated with the second phase difference plate 54.

[0115] The polarizing plate 57 may have the configuration of a known absorption polarizing plate. Known absorption polarizing plates may be iodine-based polarizing plates in which an iodine compound is adsorbed and oriented on a polyvinyl alcohol (PVA) film, dye-based polarizing plates in which a dichroic organic dye is adsorbed and oriented on a PVA film, and the like. The polarizing plate 57 may also have the configuration of a reflective polarizing plate.

[0116] Linearly polarized light (A) L1 emitted from the display panel 5 may pass through the first semi-transparent mirror 10X. Linearly polarized light (A) L1 may pass through the first phase difference plate 53 and be converted into first circularly polarized light C1. First circularly polarized light C1 may be incident on the second semi-transparent mirror 10Y. A portion of the first circularly polarized light C1 (for example, approximately 50%) may be reflected by the second semi-transparent mirror 10Y and converted into second circularly polarized light C2. Second circularly polarized light C2 may pass through the first phase difference plate 53 and be converted into linearly polarized light (B) L2 whose polarization characteristics are orthogonal to linearly polarized light (A) L1. Linearly polarized light (B) L2 may be reflected by the first semi-transparent mirror 10X and converted into linearly polarized light (C) L3 whose polarization characteristics are orthogonal to linearly polarized light (A) L1. Linearly polarized light (C) L3 may pass through the first phase difference plate 53 and be converted into third circularly polarized light C3. A portion (for example, approximately 50%) of the third circularly polarized light C3 may pass through the second semi-transparent mirror 10Y. The third circularly polarized light C3 that has passed through the second semi-transparent mirror 10Y may pass through the second phase difference plate 54 and be converted into linearly polarized light (D)L4 whose polarization characteristics are orthogonal to linearly polarized light (A)L1. The linearly polarized light (D)L4 may pass through the polarizing plate 57 and be emitted to the outside as polarized light 8.

[0117] The remainder of the first circularly polarized light C1 (for example, approximately 50%) may pass through the second semi-transparent mirror 10Y, then through the second phase difference plate 54, and be converted into linearly polarized light (E) L5 whose polarization characteristics are parallel to linearly polarized light (A) L1. Since linearly polarized light (E) L5 is absorbed or reflected by the polarizer plate 57, it does not need to be emitted to the outside. Linearly polarized light (E) L5 may be light that is not transmitted through the polarizer plate 57. The amount of light (luminance) emitted from the display device 2 may be, for example, approximately 25% of the amount of display light (luminance) emitted from the display panel 5.

[0118] [Embodiment 9] Figure 14 is a cross-sectional view showing yet another example of the configuration of the display device 2.

[0119] The optical system 6 may include a first semi-transparent mirror 10X, a first phase difference plate 53, a second semi-transparent mirror 10Y, a second phase difference plate 54, and a third semi-transparent mirror 10Z. The first semi-transparent mirror 10X, the first phase difference plate 53, the second semi-transparent mirror 10Y, the second phase difference plate 54, and the third semi-transparent mirror 10Z may be positioned in this order in the direction of emission of display light from the display panel 5 (positive direction in the Z-axis direction).

[0120] The first phase difference plate 53 may be located on the reflective surface 58 side of the first semi-transparent mirror 10X. The first phase difference plate 53 may be located away from the display panel 5 in the direction of emission of display light from the display panel 5. The second phase difference plate 54 may be located away from the first phase difference plate 53 in the direction of emission of display light. The first phase difference plate 53 and the second phase difference plate 54 may be quarter-wave plates. The positional relationship between the first phase difference plate 53 and the second phase difference plate 54 may be defined such that when the first phase difference plate 53 and the second phase difference plate 54 are viewed along the Z-axis direction, the lagging axis of the second phase difference plate 54 is perpendicular to the lagging axis of the first phase difference plate 53. Furthermore, the positional relationship between the first phase difference plate 53 and the second phase difference plate 54 may be defined such that, when the first phase difference plate 53 and the second phase difference plate 54 are viewed along the Z-axis direction, the retard axis of the second phase difference plate 54 and the retard axis of the first phase difference plate 53 are parallel.

[0121] The first semi-transparent mirror 10X may be positioned between the display panel 5 and the first phase difference plate 53. The first semi-transparent mirror 10X may transmit a portion of the incident light and reflect the remainder. The first semi-transparent mirror 10X may be a concave mirror having a concave reflective surface 58 on the side facing the first phase difference plate 53. The first semi-transparent mirror 10X may include a spherical shape, an aspherical shape, or a free-form shape in at least a portion of the reflective surface 58. Furthermore, the first semi-transparent mirror 10X may be composed of a holographic optical element, or its surface shape may have a Fresnel shape.

[0122] The first semi-transparent mirror 10X may be composed of, for example, a substrate and a plurality of metal nanowires (metal nanowire grids) located on the surface of the substrate. The substrate may have a transmittance of 100% or close to 100% for light in the visible light band. The substrate may be made of a resin material, a glass material, etc. The resin material may be acrylic resin, polycarbonate resin, etc. The metal nanowires may be made of a metal material such as aluminum, chromium, or titanium oxide. The metal nanowires may be arranged along one direction. The first semi-transparent mirror 10X can transmit light components vibrating in a direction perpendicular to the grid and reflect light components vibrating in a direction parallel to the grid. The metal nanowire grid may be formed on the first phase difference plate 53 side of the substrate. In this example, the metal nanowire grid provides the first semi-transparent mirror 10X with a reflective polarization function, but the first semi-transparent mirror 10X may be used as a simple half-mirror and a separate reflective polarizer may be provided.

[0123] The second semi-transparent mirror 10Y may be positioned between the first phase difference plate 53 and the second phase difference plate 54. The second semi-transparent mirror 10Y may transmit a portion of the incident light (e.g., approximately 50%) and reflect the remainder (e.g., approximately 50%). However, the transmittance and reflectance of the light incident on the second semi-transparent mirror 10Y are not limited to 50%. The second semi-transparent mirror 10Y may be a plane mirror having a reflective surface 59 on the first phase difference plate 53 side and a reflective surface 60 on the second phase difference plate 54 side. The second semi-transparent mirror 10Y may also be called a plane half-mirror. Furthermore, the second semi-transparent mirror 10Y may be composed of a holographic optical element, or its surface shape may have a Fresnel shape. The second semi-transparent mirror 10Y may be integrated with the first phase difference plate 53 and / or the second phase difference plate 54.

[0124] The second semi-transparent mirror 10Y may be composed of, for example, a substrate and a semi-transparent layer located on the surface of the substrate. The substrate may have a transmittance of 100% or close to 100% for light in the visible light band. The substrate may be made of inorganic glass, resin material, etc. The resin material may be acrylic resin, polycarbonate resin, etc. The semi-transparent layer may be a thin metal film. The thin metal film may be made of a metal material such as aluminum or chromium. The semi-transparent layer is not limited to a thin metal film and may be a dielectric multilayer film, etc. The first phase difference plate 53 and the second phase difference plate 54 may be fixed to the second semi-transparent mirror 10Y with an optically transparent adhesive such as OCA. The adhesive may be a material with low retardation.

[0125] The third semi-transparent mirror 10Z may be located on the opposite side of the second semi-transparent mirror 10Y from the second phase difference plate 54. The third semi-transparent mirror 10Z may be located downstream of the second phase difference plate 54 in the direction of emission of display light from the display panel 5. The third semi-transparent mirror 10Z may transmit a portion of the incident light and reflect the remainder. The third semi-transparent mirror 10Z may be a concave mirror having a concave reflective surface 61 on the second phase difference plate 54 side. The third semi-transparent mirror 10Z may include a spherical shape, an aspherical shape, or a free-form shape in at least a portion of the reflective surface 61. Furthermore, the third semi-transparent mirror 10Z may be composed of a holographic optical element, or its surface shape may have a Fresnel shape.

[0126] The third semi-transparent mirror 10Z may be composed of, for example, a substrate and a plurality of metal nanowires (metal nanowire grids) located on the surface of the substrate. The substrate may have a transmittance of 100% or close to 100% for light in the visible light band. The substrate may be made of a resin material, a glass material, etc. The resin material may be acrylic resin, polycarbonate resin, etc. The metal nanowires may be made of a metal material such as aluminum, chromium, or titanium oxide. The metal nanowires may be arranged along one direction. The third semi-transparent mirror 10Z can transmit light components vibrating in a direction perpendicular to the grid and reflect light components vibrating in a direction parallel to the grid. The metal nanowire grid may be formed on the second phase difference plate 54 side of the substrate. In this example, the metal nanowire grid provides the third semi-transparent mirror 10Z with a reflective polarization function, but the third semi-transparent mirror 10Z may be used as a simple half-mirror and a separate reflective polarizer may be provided.

[0127] In the display device 2, linearly polarized light (A) L1 emitted from the display panel 5 may travel along path P1 or path P2 and be emitted to the outside. First, the light traveling along path P1 will be described. Linearly polarized light (A) L1 emitted from the display panel 5 may pass through the first semi-transparent mirror 10X. Linearly polarized light (A) L1 may pass through the first phase difference plate 53 and be converted into first circularly polarized light C1. The first circularly polarized light C1 may be incident on the second semi-transparent mirror 10Y. A portion of the first circularly polarized light C1 (for example, approximately 50%) may be reflected by the second semi-transparent mirror 10Y and converted into second circularly polarized light C2. The second circularly polarized light C2 may pass through the first phase difference plate 53 and be converted into linearly polarized light (B) L2 whose polarization characteristics are orthogonal to linearly polarized light (A) L1. Linearly polarized light (B)L2 may be reflected by the first semi-transparent mirror 10X and converted to linearly polarized light (C)L3 whose polarization characteristics are orthogonal to linearly polarized light (A)L1. Linearly polarized light (C)L3 may be transmitted through the first phase difference plate 53 and converted to third circularly polarized light C3. Third circularly polarized light C3 may be incident on the second semi-transparent mirror 10Y. A portion of the third circularly polarized light C3 (for example, approximately 50%) may be transmitted through the second semi-transparent mirror 10Y. Third circularly polarized light C3 that has been transmitted through the second semi-transparent mirror 10Y may be transmitted through the second phase difference plate 54 and converted to linearly polarized light (D)L4 whose polarization characteristics are orthogonal to linearly polarized light (A)L1. Linearly polarized light (D)L4 may be transmitted through the third semi-transparent mirror 10Z and emitted to the outside.

[0128] Next, we will describe the light traveling along path P2. The remainder (for example, approximately 50%) of the first circularly polarized light C1 incident on the second semi-transparent mirror 10Y may pass through the second semi-transparent mirror 10Y. The first circularly polarized light C1 that has passed through the second semi-transparent mirror 10Y may pass through the second phase difference plate 54 and be converted into linearly polarized light (E) L5 whose polarization characteristics are parallel to linearly polarized light (A) L1. Linearly polarized light (E) L5 may be reflected by the third semi-transparent mirror 10Z and converted into linearly polarized light (F) L6 whose polarization characteristics are parallel to linearly polarized light (A) L1. Linearly polarized light (F) L6 may pass through the second phase difference plate 54 and be converted into fourth circularly polarized light C4. The fourth circularly polarized light C4 may be incident on the second semi-transparent mirror 10Y. A portion (for example, approximately 50%) of the fourth circularly polarized light C4 may be reflected by the second semi-transparent mirror 10Y and converted into fifth circularly polarized light C5. The fifth circularly polarized light C5 may pass through the second phase difference plate 54 and be converted to linearly polarized light (G)L7 whose polarization characteristics are orthogonal to linearly polarized light (A)L1. The linearly polarized light (G)L7 may pass through the third semi-transparent mirror 10Z and be emitted to the outside.

[0129] Polarization 8 may include linearly polarized light (D) L4 emitted to the outside via path P1, and linearly polarized light (G) L7 emitted to the outside via path P2.

[0130] The amount of light (luminance) emitted from the display device 2 may be, for example, approximately 50% of the amount of display light (luminance) emitted from the display panel 5. The display device 2 can improve light utilization efficiency and increase the luminance of the light emitted to the outside.

[0131] [Embodiment 10] Figure 15 is a cross-sectional view showing the configuration of a vehicle 201 according to Embodiment 10 of the present disclosure. Figure 16 is a diagram showing the internal configuration of a vehicle 201 according to Embodiment 10 of the present disclosure.

[0132] The imaging device 151 may be mounted on a vehicle 201. The vehicle 201 may be an example of a mobile body on which the imaging device 151 is mounted. However, the mobile body on which the imaging device 151 is mounted is not limited to a vehicle 201, but may be an aircraft, a ship, or the like. The vehicle 201 is not limited to a passenger car, but may be a truck, bus, trolleybus or other automobile, or a motorcycle. The position of the display unit 101 may be arbitrary within the vehicle 201. The display unit 101 may be located on the dashboard (instrument panel), inside the dashboard, on the ceiling of the passenger compartment, on the A-pillar, etc. The imaging device 151 may share some of its components with other devices and parts provided by the vehicle 201.

[0133] As an example of this disclosure, the imaging device 151 may constitute a display system comprising a display unit 101 and a camera 152 that captures the scenery around the vehicle 201. Here, the scenery around the vehicle 201 may be at least one of the front, rear, sides, above, and below the vehicle 201. The camera 152 may include, for example, a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor. The display unit 101 and the camera 152 may be connected by wired communication and / or wireless communication. In the vehicle 201, the display unit 101 and the camera 152 may be connected via a vehicle network such as a CAN (Control Area Network). Here, the imaging device 151 is described as comprising a display unit 101 and a camera 152, but the imaging device 151 may also comprise the display system 100A or display system 100B of this disclosure. In other words, the imaging device 151 may constitute a display system comprising a display system 100A or a display system 100B and a camera 152.

[0134] In the following explanation, for a specific example of a component, a code with a capital letter appended to the previously mentioned code may be used. For example, display image 51A is a specific example of the display image 51 described above. To simplify the illustration, codes with a capital letter appended to the previously mentioned code will not necessarily be shown.

[0135] The display unit 101 may be configured to display at least a portion of the captured image captured by the camera 152 on the first display panel 5a and / or the second display panel 5b. In this case, the imaging device 151 can make the scenery around the vehicle 201 visible to the viewer 102 as a display image 51A. As a result, the viewer 102 can view the scenery around the vehicle 201 without significantly changing the gaze distance and gaze point while driving the vehicle 201, making it easier to see the display image 51A and improving driving safety. Furthermore, since the imaging device 151 is a small imaging device, even if it is placed in the driver's cab of the vehicle 201, it will not occupy a large volume in the driver's cab and will not interfere with driving. The display unit 101 mounted on the vehicle 201 and configured to make the scenery around the vehicle 201 (for example, an image of the rear of the vehicle 201) visible to the viewer 102 as a display image 51A may also be called a digital rearview mirror.

[0136] The imaging device 151 may be applied to a digital side mirror. In this case, the imaging device 151 may include a display unit 101L located on the left A-pillar of the vehicle 201 and a camera 152L that captures the left rear of the vehicle 201. Alternatively, the imaging device 151 may include a display unit 101R located on the right A-pillar of the vehicle 201 and a camera 152R that captures the right rear of the vehicle 201. The display unit 101L may display the image of the left rear of the vehicle 201 captured by the camera 152L as a display image 51B for the viewer 102 to see. The display unit 101R may display the image of the right rear of the vehicle 201 captured by the camera 152R as a display image 51C for the viewer 102 to see. The image may be a moving image or a still image. Camera 152L may be positioned in the same location as the left-side door mirror, and camera 152R may be positioned in the same location as the right-side door mirror.

[0137] The imaging device 151 may be configured such that the distance between the viewer's eye or eyebox and the displayed image 51B and displayed image 51C are approximately equal to each other. In this case, the viewer 102 can check the situation on the left rear and right rear of the vehicle 201 without significantly changing the gaze distance. Therefore, driving safety can be improved. The eyebox may mean the area in real space where the viewer's eye is assumed to be located. The gaze distance may be the distance between the viewer's eye and the point of focus that the viewer 102 is looking at.

[0138] The imaging device 151 may be configured such that the distance between the viewer's eye or eyebox and each of the displayed images 51A, 51B, and 51C is approximately equal to each other. In this case, the viewer 102 can check the situation immediately behind, to the left rear, and to the right rear of the vehicle 201 without significantly changing the viewing distance. Therefore, driving safety can be improved.

[0139] The imaging device 151 may be applied to a cluster 153 in the dashboard of the vehicle 201. In this case, the display unit 101 may display an image 51D showing driving-related information such as vehicle speed, engine speed, and fuel level to the viewer 102.

[0140] The imaging device 151 may be applied to a CID (Center Information Display) 154. In this case, the display device unit 101 is located in the center cluster of the vehicle 201 and may display images 51E showing information related to navigation, the in-vehicle environment (settings for air conditioning, audio equipment, etc.) to the viewer 102.

[0141] The imaging device 151 may be configured such that the distance between the viewer's eye or eyebox and the displayed image 51D and displayed image 51E are approximately equal to each other. In this case, the viewer 102 can confirm information related to the operation of the vehicle 201, as well as information related to navigation, the in-vehicle environment, etc., without significantly changing the gaze distance. Therefore, driving safety can be improved.

[0142] The imaging device 151 may be configured such that the distance between the viewer's eye or eyebox and each of the displayed images 51A, 51B, 51C, 51D, and 51E is approximately the same. In this case, the viewer 102 can check the area directly behind, to the left rear, and to the right rear of the vehicle 201 without significantly changing the viewing distance, and can also check information related to the vehicle 201's operation, navigation, and in-vehicle environment. Therefore, driving safety can be improved.

[0143] The imaging device 151 may be applied to a PID (Passenger Information Display) 155. In this case, the display unit 101 may be positioned near the passenger seat on the dashboard, and the passenger may view the display image 51 showing images of entertainment content and information related to audio equipment, air conditioning equipment, etc.

[0144] The imaging device 151 may be applied to the RSE (Rear Seat Entertainment) system 156. In this case, the display unit 101 is positioned on the back of the front seats and displays images 51 of entertainment content and information related to audio equipment, air conditioning equipment, etc., which can be viewed by passengers seated in the rear seats of the vehicle 201.

[0145] [Embodiment 11] Figure 18 is a schematic cross-sectional view showing the configuration of a display system 111A according to Embodiment 11 of the present disclosure. In the diagrams showing optical paths from Figure 18 onward, for the sake of ease of illustration, the axis of the optical path of light incident approximately perpendicularly to the reflective surface of a certain member and the axis of the optical path of light reflected approximately perpendicularly by the same member are shown to be offset. However, in reality, these two optical paths may be located approximately on the same axis.

[0146] As shown in Figure 18, the display system 111A may include a housing 1, a first display panel 5a, a second display panel 5b, an optical system 6, and a touch panel 15. The display system 111A according to this embodiment may be an example of the display system 100A. That is, the optical system 6 may form images of the first image 9a and the second image 9b such that at least a portion of the first image 9a and at least a portion of the second image 9b overlap when the inside of the housing 1 is viewed from the opening 4.

[0147] The first display panel 5a may have a first display surface 55a for displaying a first display image 7a. The second display panel 5b may have a second display surface 55b for displaying a second display image 7b.

[0148] The first display panel 5a and the second display panel 5b may be located inside the housing 1. Alternatively, the first display panel 5a and the second display panel 5b may be located outside the housing 1. In this case, the housing 1 may have openings in which a portion of the wall surface is cut out at positions corresponding to the first display panel 5a and the second display panel 5b, respectively. The first display panel 5a and the second display panel 5b may be arranged relative to the housing 1 so that the display light emitted from each of the first and second display panels 5b is guided into the interior of the housing 1 through the respective openings. The first display panel 5a and the second display panel 5b may be arranged corresponding to the respective openings, may be arranged to block at least a portion of the respective openings, and may be connected to the outer wall of the housing 1. A light-transmitting member may be placed in each of the openings, and this member may be, for example, glass or resin.

[0149] The touch panel 15 may be located in the opening 4, as described above. The optical system 6 may be located inside the housing 1. In this embodiment, the optical system 6 may include a first semi-transparent mirror 10a, a second semi-transparent mirror 10b, a first phase difference plate 16a, a second phase difference plate 16b, a third phase difference plate 16c, a fourth phase difference plate 16d, a reflecting mirror 17, and a first reflective polarizing plate 18a.

[0150] The first reflective polarizer 18a may have a first optical surface 185 on the touch panel 15 side and a second optical surface 186 on the opposite side of the first optical surface 185. The first reflective polarizer 18a may transmit first linearly polarized light and reflect second linearly polarized light. However, the first reflective polarizer 18a may transmit second linearly polarized light and reflect first linearly polarized light.

[0151] The first reflective polarizer 18a may be a wire grid polarizer comprising a substrate and a plurality of metal nanowires (also called a metal nanowire grid) located on the surface of the substrate. The metal nanowires may be made of a metal material such as aluminum, chromium, or titanium oxide. The metal nanowires may be arranged in one direction. The substrate may have a transmittance of 100% or close to 100% for light in the visible light band. The substrate may be made of a resin material, a glass material, or the like. The first reflective polarizer 18a can transmit light components vibrating in a direction perpendicular to the grid and reflect light components vibrating in a direction parallel to the grid.

[0152] The reflector 17 may reflect light incident from the first reflective polarizer 18a side. The reflector 17 may have a reflective surface 175. The reflector 17 may be positioned such that its reflective surface 175 faces the first reflective polarizer 18a side. The reflector 17 may, for example, reflect all of the incident light, reflect 95% or more, or reflect 90% or more. Alternatively, for example, the reflector 17 may be a planar mirror whose reflective surface 175 is planar. In this case, the reflector 17 may be referred to as a planar full mirror. In this disclosure, "planar" means that it is not a curved surface at a visible level, or that it does not have visible irregularities, and does not require that it be strictly flat.

[0153] The reflector 17 may be composed of, for example, a substrate and a reflective layer located on the surface of the substrate. The substrate may be made of, for example, a resin material, a glass material, etc. The resin material may be, for example, an acrylic resin, a polycarbonate resin, etc. The reflective layer may be a thin metal film. The thin metal film may be made of, for example, a metal material such as aluminum or chromium. The reflective layer is not limited to a thin metal film, and may be, for example, a dielectric multilayer film. The surface of the reflective layer is a reflective surface 175, and light may be reflected by the reflective surface 175.

[0154] The first reflective polarizer 18a may be positioned between the first display panel 5a and the reflector 17, and also between the second display panel 5b and the touch panel 15. When the display system 111A is placed on a horizontal surface, if the upward direction is the +Y axis, the reflector 17 may be located on the upper side of the housing 1 in the display system 111A. The first display panel 5a may be located on the bottom side of the housing 1. The second display panel 5b may be located on the housing 1 on the side opposite to the touch panel 15. The first reflective polarizer 18a may be positioned such that the first optical surface 185 faces the first display surface 55a and the touch panel 15, and the second optical surface 186 faces the reflective surface 175 and the second display surface 55b. The first reflective polarizer 18a may be positioned at an angle of approximately 45° with respect to the XY plane. In this embodiment, as shown in Figure 18, the first reflective polarizing plate 18a may be tilted at approximately 45° with respect to the plane parallel to the touch panel 15.

[0155] Approximately 45° may be, for example, 35° to 55°, 40° to 50°, or 43° to 48°. This angle of inclination may be adjusted to allow the propagation of light as shown in Figure 18, and is not limited to approximately 45°. Furthermore, the first reflective polarizer 18a may be positioned at an angle of approximately 45° with respect to at least one of the first normal of the first display surface 55a, the second normal of the second display surface 55b, and the third normal of the reflective surface 175. For example, the angle between at least one of the first, second, and third normals and the fourth normal of the first optical surface 185 and the second optical surface 186 may be approximately 45°. These angle considerations also apply when the second reflective polarizer 18b, described later, is used instead of the first reflective polarizer 18a.

[0156] The first semi-transparent mirror 10a is positioned between the first display panel 5a and the first reflective polarizer 18a, and may transmit light incident from the first display panel 5a side and reflect light incident from the first reflective polarizer 18a side.

[0157] The first semi-transparent mirror 10a may transmit a portion of the incident light (for example, approximately 50%) and reflect the remainder (for example, approximately 50%). However, the transmittance and reflectance of the light incident on the first semi-transparent mirror 10a are not limited to 50%. The first semi-transparent mirror 10a may have a function to collect or focus light. Specifically, the first semi-transparent mirror 10a may have a function to collect or focus light that has been incident on and reflected by the first semi-transparent mirror 10a. For example, the first semi-transparent mirror 10a may be a concave mirror having a concave first reflective surface 105a arranged on the side of the first reflective polarizer 18a. In this case, the first semi-transparent mirror 10a may be called a concave half-mirror. The first semi-transparent mirror 10a may include a spherical shape, an aspherical shape, or a free-form shape in at least a portion of the first reflective surface 105a. Furthermore, the first semi-transparent mirror 10a may be composed of a holographic optical element, or its surface shape may have a Fresnel shape.

[0158] The first semi-transparent mirror 10a may be composed of, for example, a substrate and a semi-transparent reflective layer located on the surface of the substrate. The substrate may have a transmittance of 100% or close to 100% for light in the visible light band. The substrate may be made of a resin material, a glass material, etc. The resin material may be an acrylic resin, a polycarbonate resin, etc. The semi-transparent reflective layer may be a thin metal film. The thin metal film may be made of a metal material such as aluminum or chromium. The semi-transparent reflective layer is not limited to a thin metal film, but may also be a dielectric multilayer film, etc. The first semi-transparent mirror 10a may be configured to reflect light by the semi-transparent reflective layer. The semi-transparent reflective layer may be formed on the surface of the substrate on the side of the first reflective polarizer 18a. The surface of the semi-transparent reflective layer may be the first reflective surface 105a, and light may be reflected by the first reflective surface 105a.

[0159] The second semi-transparent mirror 10b is positioned between the second display panel 5b and the first reflective polarizer 18a, and may transmit light incident from the second display panel 5b side and reflect light incident from the first reflective polarizer 18a side.

[0160] The second semi-transparent mirror 10b may transmit a portion of the incident light (e.g., approximately 50%) and reflect the remainder (e.g., approximately 50%). However, the transmittance and reflectance of the light incident on the second semi-transparent mirror 10b are not limited to 50%. The second semi-transparent mirror 10b may have a function to collect or focus light. Specifically, the second semi-transparent mirror 10b may have a function to collect or focus light that has been incident on and reflected by the second semi-transparent mirror 10b. For example, the second semi-transparent mirror 10b may be a concave mirror having a concave second reflective surface 105b arranged on the first reflective polarizer 18a side. In this case, the second semi-transparent mirror 10b may be called a concave half-mirror. The second semi-transparent mirror 10b may include a spherical shape, an aspherical shape, or a free-form shape in at least a portion of the second reflective surface 105b. Furthermore, the second semi-transparent mirror 10b may be composed of a holographic optical element, or its surface shape may have a Fresnel shape.

[0161] The second semi-transparent mirror 10b may be composed of, for example, a substrate and a semi-transparent reflective layer located on the surface of the substrate. The substrate may have a transmittance of 100% or close to 100% for light in the visible light band. The substrate may be made of a resin material, a glass material, etc. The resin material may be an acrylic resin, a polycarbonate resin, etc. The semi-transparent reflective layer may be a thin metal film. The thin metal film may be made of a metal material such as aluminum or chromium. The semi-transparent reflective layer is not limited to a thin metal film, but may also be a dielectric multilayer film, etc. The second semi-transparent mirror 10b may be configured to reflect light by the semi-transparent reflective layer. The semi-transparent reflective layer may be formed on the surface of the substrate on the side of the first reflective polarizer 18a. The surface of the semi-transparent reflective layer may be the second reflective surface 105b, and light may be reflected by the second reflective surface 105b.

[0162] The size of the first semi-transparent mirror 10a may be larger than the size of the second semi-transparent mirror 10b, or smaller than the size of the second semi-transparent mirror 10b. Alternatively, the size of the first semi-transparent mirror 10a may be the same as the size of the second semi-transparent mirror 10b. The size of the first semi-transparent mirror 10a may be the size when viewed along the optical axis of the first semi-transparent mirror 10a. The size of the second semi-transparent mirror 10b may be the size when viewed along the optical axis of the second semi-transparent mirror 10b.

[0163] Furthermore, the index expressed as the reciprocal of the focusing degree, focusing degree, or focal length of the first semi-transparent mirror 10a may be greater than or less than the index expressed as the reciprocal of the focusing degree, focusing degree, or focal length of the second semi-transparent mirror 10b. Also, the index expressed as the reciprocal of the focusing degree, focusing degree, or focal length of the first semi-transparent mirror 10a may be the same as the index expressed as the reciprocal of the focusing degree, focusing degree, or focal length of the second semi-transparent mirror 10b.

[0164] The first phase difference plate 16a may be located between the first display panel 5a and the first semi-transparent mirror 10a. The first phase difference plate 16a may be integrated with the first display panel 5a, or it may be located separately from the first display panel 5a. Alternatively, the first phase difference plate 16a may be integrated with the first semi-transparent mirror 10a, or it may be located separately from the first semi-transparent mirror 10a.

[0165] The second phase difference plate 16b may be positioned between the first semi-transparent mirror 10a and the first reflective polarizer 18a. The second phase difference plate 16b may be integrated with the first semi-transparent mirror 10a, or it may be positioned separately from the first semi-transparent mirror 10a. Alternatively, the second phase difference plate 16b may be integrated with the first reflective polarizer 18a, or it may be positioned separately from the first reflective polarizer 18a. For example, the second phase difference plate 16b may be positioned in contact with the first optical surface 185 of the first reflective polarizer 18a, or it may be bonded to the first optical surface 185.

[0166] The first phase difference plate 16a is emitted from the first display panel 5a, and the light transmitted through the first phase difference plate 16a should be given the necessary phase difference so that the light transmitted through the first phase difference plate 16a is transmitted through the first reflective polarizer 18a. The second phase difference plate 16b is emitted from the first display panel 5a, and the light transmitted through the second phase difference plate 16b should be given the necessary phase difference so that the light transmitted through the first phase difference plate 16a and the second phase difference plate 16b is transmitted through the first reflective polarizer 18a. Furthermore, the second phase difference plate 16b is reflected by the first semi-transparent mirror 10a, and the light transmitted through the second phase difference plate 16b should be given the necessary phase difference so that the light transmitted through the second phase difference plate 16b is reflected by the first reflective polarizer 18a.

[0167] As long as such a phase difference can be provided, the first phase difference plate 16a and the second phase difference plate 16b may be quarter-wave plates, i.e., λ / 4 wave plates, or they may be other wave plates or combinations thereof. The first phase difference plate 16a and the second phase difference plate 16b may be film-like members.

[0168] The third phase difference plate 16c may be located between the second display panel 5b and the second semi-transparent mirror 10b. The third phase difference plate 16c may be integrated with the second display panel 5b, or it may be located separately from the second display panel 5b. Alternatively, the third phase difference plate 16c may be integrated with the second semi-transparent mirror 10b, or it may be located separately from the second semi-transparent mirror 10b.

[0169] The fourth phase difference plate 16d may be located between the second semi-transparent mirror 10b and the first reflective polarizer 18a. The fourth phase difference plate 16d may be integrated with the second semi-transparent mirror 10b, or it may be located separately from the second semi-transparent mirror 10b.

[0170] The third phase difference plate 16c is emitted from the second display panel 5b, and the light transmitted through the third phase difference plate 16c should be given the necessary phase difference so that the light transmitted through the third phase difference plate 16c is reflected by the first reflective polarizer 18a. The fourth phase difference plate 16d is emitted from the second display panel 5b, and the light transmitted through the fourth phase difference plate 16d should be given the necessary phase difference so that the light transmitted through the third phase difference plate 16c and the fourth phase difference plate 16d is reflected by the first reflective polarizer 18a. Furthermore, the fourth phase difference plate 16d is reflected by the second semi-transparent mirror 10b, and the light transmitted through the fourth phase difference plate 16d should be given the necessary phase difference so that the light transmitted through the fourth phase difference plate 16d is transmitted through the first reflective polarizer 18a.

[0171] As long as such a phase difference can be provided, the third phase difference plate 16c and the fourth phase difference plate 16d may be quarter-wave plates, or they may be other wave plates or a combination thereof. The third phase difference plate 16c and the fourth phase difference plate 16d may be film-like members.

[0172] Next, an example of the propagation of light emitted from the first display panel 5a will be described. The display light emitted from the first display panel 5a may be, for example, S-polarized light. Also, the first linearly polarized light may be, for example, S-polarized light, and the second linearly polarized light, which has a different polarization state from the first linearly polarized light, may be, for example, P-polarized light. Also, the first circularly polarized light may be, for example, right-handed circularly polarized light, and the second circularly polarized light, which has a different polarization state from the first circularly polarized light, may be, for example, left-handed circularly polarized light.

[0173] However, the display light emitted from the first display panel 5a may be, for example, P-polarized light. Also, the first linearly polarized light may be, for example, P-polarized light, and the second linearly polarized light may be, for example, S-polarized light. Also, the first circularly polarized light may be, for example, left-handed circularly polarized light, and the second circularly polarized light may be, for example, right-handed circularly polarized light. Each phase difference plate and the like converts the polarization state of the incident light so that the light emitted from the first display panel 5a is guided to the touch panel 15 side along the optical path shown in Figure 18, and the first reflective polarizer 18a transmits or reflects the incident light.

[0174] Linearly polarized display light emitted from the first display panel 5a may be converted into first circularly polarized light by passing through the first phase difference plate 16a, passing through the first semi-transparent mirror 10a, and being guided to the second phase difference plate 16b. First circularly polarized light incident on the second phase difference plate 16b may be converted into first linearly polarized light by passing through the second phase difference plate 16b, and being guided to the first reflective polarizer 18a.

[0175] The first reflective polarizer 18a may transmit light of the first linear polarization and reflect light of the second linear polarization. Therefore, light of the first linear polarization incident on the first reflective polarizer 18a may pass through the first reflective polarizer 18a and be guided to the reflector 17. Light of the first linear polarization incident on the reflector 17 may be reflected at the reflective surface 175 and guided to the first reflective polarizer 18a.

[0176] First linearly polarized light incident on the first reflecting polarizer 18a may pass through the first reflecting polarizer 18a and be guided to the second phase difference plate 16b. First linearly polarized light incident on the second phase difference plate 16b may be converted into first circularly polarized light by passing through the second phase difference plate 16b and be guided to the first semitransparent mirror 10a.

[0177] Light of first circular polarization incident on the first semi-transparent mirror 10a may be converted into light of second circular polarization by reflection at the first reflective surface 105a and guided to the second phase difference plate 16b. Light of second circular polarization incident on the second phase difference plate 16b may be converted into light of second linear polarization by transmission through the second phase difference plate 16b and guided to the first reflective polarizer 18a. Light of second linear polarization incident on the first reflective polarizer 18a may be reflected at the first optical surface 185 and guided to the touch panel 15.

[0178] Next, an example of the propagation of light emitted from the second display panel 5b will be described. The display light emitted from the second display panel 5b may be, for example, P-polarized light. However, the display light emitted from the second display panel 5b may also be, for example, S-polarized light. Each phase difference plate and the like should convert the polarization state of the incident light so that the light emitted from the second display panel 5b is guided to the touch panel 15 side along the optical path shown in Figure 18, and the first reflective polarizer 18a should transmit or reflect the incident light.

[0179] Linearly polarized display light emitted from the second display panel 5b may be converted into second circularly polarized light by passing through the third phase difference plate 16c, passing through the second semi-transparent mirror 10b, and being guided to the fourth phase difference plate 16d. Second circularly polarized light incident on the fourth phase difference plate 16d may be converted into second linearly polarized light by passing through the fourth phase difference plate 16d, and being guided to the first reflective polarizer 18a. Second linearly polarized light incident on the first reflective polarizer 18a may be reflected at the second optical surface 186 and guided to the reflecting mirror 17. Second linearly polarized light incident on the reflecting mirror 17 may be reflected at the reflective surface 175 and guided to the first reflective polarizer 18a.

[0180] Light of the second linear polarization incident on the first reflective polarizer 18a may be reflected at the second optical surface 186 and guided to the fourth phase difference plate 16d. Light of the second linear polarization incident on the fourth phase difference plate 16d may be converted into light of the second circular polarization by passing through the fourth phase difference plate 16d and guided to the second semitransparent mirror 10b.

[0181] The second circularly polarized light incident on the second semi-transparent mirror 10b may be converted to first circularly polarized light by reflection at the second reflective surface 105b and guided to the fourth phase difference plate 16d. The first circularly polarized light incident on the fourth phase difference plate 16d may be converted to first linearly polarized light by passing through the fourth phase difference plate 16d and guided to the first reflective polarizer 18a. The first linearly polarized light incident on the first reflective polarizer 18a may pass through the first reflective polarizer 18a and guided to the touch panel 15.

[0182] Thus, the first reflective polarizing plate 18a may transmit light emitted from the first display panel 5a, which has passed through the first phase difference plate 16a, the first semi-transparent mirror 10a, and the second phase difference plate 16b, as first linearly polarized light and guide it toward the reflecting mirror 17. Then, the light reflected by the reflecting mirror 17 may be transmitted as first linearly polarized light and guided toward the first semi-transparent mirror 10a, and the light reflected by the first semi-transparent mirror 10a and transmitted through the second phase difference plate 16b may be reflected as second linearly polarized light and guided toward the touch panel 15.

[0183] Furthermore, the first reflective polarizing plate 18a may reflect light emitted from the second display panel 5b, which has passed through the third phase difference plate 16c, the second semi-transparent mirror 10b, and the fourth phase difference plate 16d, as second linearly polarized light and guide it toward the reflecting mirror 17. Then, the light reflected by the reflecting mirror 17 may be reflected as second linearly polarized light and guided toward the second semi-transparent mirror 10b, and the light reflected by the second semi-transparent mirror 10b and passed through the fourth phase difference plate 16d may be transmitted as first linearly polarized light and guided toward the touch panel 15.

[0184] For example, the first reflective polarizer 18a may be configured to transmit polarized light having a polarization axis parallel to the polarization axis of the display light emitted from the first display panel 5a, and to reflect polarized light having a polarization axis perpendicular to the polarization axis of the display light. In this case, the positional relationship between the first phase difference plate 16a and the second phase difference plate 16b may be defined such that when the first phase difference plate 16a and the second phase difference plate 16b are viewed along the Y-axis, the lagging axis of the second phase difference plate 16b is perpendicular to the lagging axis of the first phase difference plate 16a. Alternatively, for example, the first reflective polarizer 18a may be configured to transmit polarized light having a polarization axis perpendicular to the polarization axis of the display light emitted from the first display panel 5a, and to reflect polarized light having a polarization axis parallel to the polarization axis of the display light. In this case, the positional relationship between the first phase difference plate 16a and the second phase difference plate 16b may be defined such that when the first phase difference plate 16a and the second phase difference plate 16b are viewed along the Y-axis, the lagging axis of the second phase difference plate 16b and the lagging axis of the first phase difference plate 16a are parallel. Alternatively, for example, the first reflective polarizing plate 18a may be configured to transmit polarized light having a polarization axis perpendicular to the polarization axis of the display light emitted from the second display panel 5b, and to reflect polarized light having a polarization axis parallel to the polarization axis of the display light. In this case, the positional relationship between the third phase difference plate 16c and the fourth phase difference plate 16d may be defined such that when the third phase difference plate 16c and the fourth phase difference plate 16d are viewed along the Z-axis, the lagging axis of the fourth phase difference plate 16d and the lagging axis of the third phase difference plate 16c are perpendicular. For example, the first reflective polarizing plate 18a may be configured to transmit polarized light having a polarization axis parallel to the polarization axis of the display light emitted from the second display panel 5b, and to reflect polarized light having a polarization axis perpendicular to the polarization axis of the display light. In this case, the positional relationship between the third phase difference plate 16c and the fourth phase difference plate 16d may be defined such that when the third phase difference plate 16c and the fourth phase difference plate 16d are viewed along the Z-axis direction, the lagging axis of the fourth phase difference plate 16d is parallel to the lagging axis of the third phase difference plate 16c.

[0185] Therefore, the display system 111A can make the first image 9a and the second image 9b, which are imaged by the optical system 6, visible to the viewer 102 using the first reflective polarizer 18a. Furthermore, since the first reflective polarizer 18a reflects light incident from the first display panel 5a side and guides it toward the touch panel 15 side, the first image 9a can be made visible to the viewer 102 even in a configuration where the first display panel 5a is not positioned facing the touch panel 15 side. In addition, because the first reflective polarizer 18a transmits light incident from the second display panel 5b side and guides it toward the touch panel 15 side, the optical system 6 can easily form an image such that at least a part of the first image 9a and at least a part of the second image 9b overlap.

[0186] In this embodiment, the focal length of the first semi-transparent mirror 10a is the optical path length of the light emitted from the first display panel 5a, and may be shorter than the optical path length from the first display panel 5a to the first semi-transparent mirror 10a, where the light emitted from the first display panel 5a passes through and re-enters the first semi-transparent mirror 10a. It can also be said that the optical path length of the light emitted from the first display panel 5a, passing through the first semi-transparent mirror 10a, reflected by the reflecting mirror 17, and reaching the first semi-transparent mirror 10a may be greater than the focal length of the first semi-transparent mirror 10a. This optical path length may be called the first optical path length. In this case, the optical system 6 can form a real image as the first image 9a, and allow the viewer 102 to see the real image.

[0187] Furthermore, the focal length of the second semi-transparent mirror 10b is the optical path length of the light emitted from the second display panel 5b, and may be longer than the optical path length from the second display panel 5b until the light emitted from the second display panel 5b passes through the second semi-transparent mirror 10b and re-enters the second semi-transparent mirror 10b. It can also be said that the optical path length of the light emitted from the second display panel 5b, passing through the second semi-transparent mirror 10b, reflected by the reflecting mirror 17, and reaching the second semi-transparent mirror 10b may be smaller than the focal length of the second semi-transparent mirror 10b. This optical path length may be called the second optical path length. In this case, the optical system 6 can form a virtual image as the second image 9b, and the viewer 102 can perceive the virtual image. In the figures from Figure 18 onward, optical paths with the first optical path length are shown by dashed lines, and optical paths with the second optical path length are shown by dashed lines.

[0188] The optical system 6 forms a real image as the first image 9a, and as shown in Figure 18, it can form the first image 9a in front of the first display panel 5a, i.e., on the touch panel 15 side. This "in front" may mean the front of the first display panel 5a when the first display panel 5a is positioned to face the touch panel 15 side while maintaining the first optical path length. The optical system 6 can form the first image 9a at the same position as or near the touch panel 15, for example. Alternatively, the first image 9a may be formed inside the housing 1. That is, it may be formed behind the touch panel 15 of the housing 1. Alternatively, the first image 9a may be formed outside the housing 1 in the direction (+Z axis direction) when looking from inside the housing 1 towards the touch panel 15 side. That is, the first image 9a may be formed in front of the touch panel 15 of the housing 1. In this case, the viewer 102 can see the image formed in front of the housing 1. Furthermore, since the optical system 6 forms a virtual image as the second image 9b, the second image 9b can be formed on the side opposite to the touch panel 15 relative to the second display panel 5b, as shown in Figure 18. Therefore, a method of using the display system 111A that takes into account the difference in the imaging positions of the first image 9a and the second image 9b can be constructed. Thus, the versatility of the display system 111A can be improved.

[0189] The first display panel 5a may, for example, display an operation image for accepting input operations as the first display image 7a. The first image 9a may be adjusted to be, for example, the same size as the touch panel 15. This allows the viewer 102 to perform input operations on the touch panel 15 to select a function to be executed by the display system 111A while viewing the first image 9a which is formed overlapping with the touch panel 15.

[0190] However, input operations via the touch panel 15 are not required in the display system 111A. In this case, the display system 111A does not need to have the touch panel 15, and may instead have, for example, a viewing window 52. Also, the opening 4 does not need to be provided with any components.

[0191] For example, if the first and second optical path lengths are a, the distance from the display panel 5 to the image 9 is b, and the magnification of the image 9 relative to the display panel 5 is m, then b and m are: b = 1 / (1 / a - 1 / f) ... (1) m = b / a ... (2) It may be calculated as follows. Equations (1) and (2) above are examples of equations for calculating the distance from the display panel 5 to the image 9 and the magnification factor. The distance from the display panel 5 to the image 9 may also be called the virtual image distance. The magnification factor may be the magnification factor of image 9 relative to the size of the display image 7 displayed on the display panel 5. In the case of a real image, b will be a negative value, so its absolute value may be taken as the virtual image distance.

[0192] For example, if the focal length of the first semi-transparent mirror 10a is 100 mm and the first optical path length is 200 mm, the distance from the first display panel 5a to the first image 9a can be determined to be 200 mm, and the magnification of the first image 9a can be determined to be 1x. In this case, since the focal length of the first semi-transparent mirror 10a is shorter than the first optical path length, the first image 9a, as a real image, may be located in front of the first display panel 5a, i.e., on the touch panel 15 side, as shown in Figure 18.

[0193] For example, if the focal length of the second semi-transparent mirror 10b is 150 mm and the second optical path length is 100 mm, the distance from the second display panel 5b to the second image 9b can be determined to be 300 mm, and the magnification of the second image 9b can be determined to be 3 times. In this case, since the focal length of the second semi-transparent mirror 10b is longer than the second optical path length, the second image 9b may be a virtual image and, as shown in Figure 18, be located behind the second display panel 5b, that is, on the opposite side of the touch panel 15 from the second display panel 5b.

[0194] The above values ​​for focal length, first optical path length, and second optical path length are merely examples. By appropriately adjusting the above values ​​for focal length, first optical path length, and second optical path length, the imaging position and size of the first image 9a as a real image can be changed, as can the imaging position and size of the second image 9b as a virtual image.

[0195] Furthermore, as shown in Figure 18, the optical system 6 may image the first image 9a and the second image 9b such that their imaging positions are different in the front-to-back direction of the housing 1. However, the optical system 6 can also image the first image 9a and the second image 9b such that their two imaging positions are the same in the front-to-back direction of the housing 1.

[0196] In the above description, the optical system 6 forms a real image as the first image 9a and a virtual image as the second image 9b, but it is not limited to this, and it may also form a virtual image as the first image 9a and a real image as the second image 9b. In this case, the focal length of the first semi-transparent mirror 10a may be longer than the first optical path length. Also, the focal length of the second semi-transparent mirror 10b may be shorter than the second optical path length. Furthermore, the optical system 6 may form real images as the first image 9a and the second image 9b, or it may form virtual images as the first image 9a and the second image 9b. In other words, the optical system 6 may form a real image as the first image 9a or a virtual image. Also, the optical system 6 may form a real image as the second image 9b or a virtual image. In other words, the focal length of the first semi-transparent mirror 10a may be shorter or longer than the first optical path length. Furthermore, the focal length of the second semi-transparent mirror 10b may be shorter or longer than the second optical path length.

[0197] Furthermore, the length of the first optical path when the first image 9a is a real image may be longer than the length of the first optical path when the first image 9a is a virtual image. Similarly, the length of the second optical path when the second image 9b is a real image may also be longer than the length of the second optical path when the second image 9b is a virtual image. Therefore, when the optical system 6 forms a real image, the length of the housing 1 in the front-to-back direction (depth direction) can be shortened by making the first image 9a a real image rather than the second image 9b a real image. On the other hand, the length of the housing 1 in the up-to-down direction (Y-axis direction) can be shortened by making the second image 9b a real image rather than the first image 9a a real image.

[0198] Furthermore, although the above description states that the reflecting mirror 17 is a plane mirror, it is not limited to this, and may be a reflecting mirror having a curved shape on at least a part of the reflective surface 175. In this case, the reflecting mirror 17 may form a virtual image or a real image as image 9. The reflecting mirror 17 may have the function of collecting or focusing light. Specifically, the reflecting mirror 17 may have the function of collecting or focusing light that has been incident on and reflected by the reflecting mirror 17. For example, the reflecting mirror 17 may be a concave mirror, where the reflective surface 175 is concave. In this case, the reflecting mirror 17 may be called a concave full mirror. In addition, the reflecting mirror 17 may have the function of reflecting and diverging light. Specifically, the reflecting mirror 17 may have the function of reflecting and diverging light that has been incident on the reflecting mirror 17. For example, the reflecting mirror 17 may be a convex mirror, where the reflective surface 175 is convex. In this case, the reflecting mirror 17 may be called a convex full mirror. Furthermore, the reflecting mirror 17 may be composed of a holographic optical element, or its surface shape may have a Fresnel shape.

[0199] Furthermore, in the above description, the first semi-transparent mirror 10a and the second semi-transparent mirror 10b were described as reflectors with curved surfaces 105a and 105b, respectively. However, they may also be planar mirrors with a planar surface 105a or 105b. In this case, the first semi-transparent mirror 10a and the second semi-transparent mirror 10b may be referred to as planar half-mirrors. In addition, the first semi-transparent mirror 10a and the second semi-transparent mirror 10b may have the function of reflecting and diverging light. Specifically, the first semi-transparent mirror 10a and the second semi-transparent mirror 10b may have the function of reflecting and diverging light incident on them. For example, the first semi-transparent mirror 10a and the second semi-transparent mirror 10b may be convex mirrors with a convex surface 105a and 105b, respectively. In this case, the first semi-transparent mirror 10a and the second semi-transparent mirror 10b may be referred to as convex half-mirrors.

[0200] Furthermore, at least one of the first semi-transparent mirror 10a and the second semi-transparent mirror 10b may have a curved reflective surface. Also, at least one of the first semi-transparent mirror 10a and the second semi-transparent mirror 10b may be composed of a holographic optical element, or its surface shape may have a Fresnel shape. Furthermore, either the first semi-transparent mirror 10a or the second semi-transparent mirror 10b may have a planar reflective surface.

[0201] [Embodiment 12] Figure 19 is a schematic cross-sectional view showing the configuration of a display system 111B according to Embodiment 12 of the present disclosure. The display system 111B according to this embodiment may be an example of the display system 100A. The display system 111B may differ from the display system 111A in the following respects: The display system 111B may include a second reflective polarizing plate 18b instead of a first reflective polarizing plate 18a. The display system 111B may include a first phase difference plate 16a and a third phase difference plate 16c, but may not include a second phase difference plate 16b and a fourth phase difference plate 16d. The display system 111B may include at least one reflector 19 instead of a reflector 17.

[0202] The second reflective polarizer 18b may have a first optical surface 185 on the touch panel 15 side and a second optical surface 186 on the opposite side of the first optical surface 185. The second reflective polarizer 18b may transmit first circularly polarized light and reflect second circularly polarized light. However, the second reflective polarizer 18b may transmit second circularly polarized light and reflect first circularly polarized light.

[0203] The second reflective polarizer 18b may include a substrate and a film that transmits first circularly polarized light and reflects second circularly polarized light. However, the second reflective polarizer 18b may include a substrate and a film that transmits second circularly polarized light and reflects first circularly polarized light. The film may be, for example, a cholesteric liquid crystal film. The substrate and the film may be integrated.

[0204] A cholesteric liquid crystal film may be a film having multiple layers in which liquid crystal molecules are arranged in the same direction, and the direction of this arrangement is slightly twisted in adjacent layers, forming a helical structure of liquid crystal molecules in the stacking direction. The substrate may have a transmittance of 100% or close to 100% for light in the visible light band. The substrate may be composed of, for example, a resin material, a glass material, etc. The resin material may be, for example, an acrylic resin, a polycarbonate resin, etc.

[0205] The reflector 19 may reflect light incident from the side of the second reflective polarizer 18b. As shown in Figure 19, in this embodiment, the display system 111B may include a first reflector 19a and a second reflector 19b as the reflector 19. The first reflector 19a may have a reflective surface 195a, and the second reflector 19b may have a reflective surface 195b.

[0206] Specifically, the first reflector 19a may be a reflective polarizer that transmits second circularly polarized light and reflects first circularly polarized light. The second reflector 19b may be a reflective polarizer that transmits first circularly polarized light and reflects second circularly polarized light. However, the first reflector 19a may be a reflective polarizer that transmits first circularly polarized light and reflects second circularly polarized light. The second reflector 19b may be a reflective polarizer that transmits second circularly polarized light and reflects first circularly polarized light. The first reflector 19a and the second reflector 19b may have the same structure as the second reflective polarizer 18b, and may include, for example, a cholesteric liquid crystal film.

[0207] The second reflective polarizer 18b may be positioned between the first display panel 5a and the reflector 19, and also between the second display panel 5b and the touch panel 15. When the display system 111B is placed on a horizontal surface, if the upward direction is the +Y axis, the reflector 19 may be located on the upper side of the housing 1 in the display system 111B. The first display panel 5a may be located on the bottom side of the housing 1. The second display panel 5b may be located on the part of the housing 1 opposite to the touch panel 15. The second reflective polarizer 18b may be positioned such that the first optical surface 185 faces the first display surface 55a and the touch panel 15, and the second optical surface 186 faces the reflective surface of the reflector 19 and the second display surface 55b. The second reflective polarizer 18b may be positioned at an angle of approximately 45° with respect to the XY plane. In this embodiment, as shown in Figure 19, the second reflective polarizing plate 18b may be tilted at approximately 45° with respect to the plane parallel to the touch panel 15.

[0208] In Figure 19, the second reflector 19b is located on the inside of the housing 1, i.e., on the side of the second reflective polarizer 18b, relative to the first reflector 19a. However, the design is not limited to this arrangement; the first reflector 19a may also be located on the inside of the housing 1, i.e., on the side of the second reflective polarizer 18b, relative to the second reflector 19b. Furthermore, the first reflector 19a may be integrated with the second reflector 19b, or it may be located separately from the second reflector 19b.

[0209] The first semi-transparent mirror 10a is positioned between the first display panel 5a and the second reflective polarizer 18b, and may transmit light incident from the first display panel 5a side and reflect light incident from the second reflective polarizer 18b side. The second semi-transparent mirror 10b is positioned between the second display panel 5b and the second reflective polarizer 18b, and may transmit light incident from the second display panel 5b side and reflect light incident from the second reflective polarizer 18b side.

[0210] Next, an example of the propagation of light emitted from the first display panel 5a will be described. The display light emitted from the first display panel 5a may be, for example, S-polarized light. Also, the first linearly polarized light may be, for example, S-polarized light, and the second linearly polarized light may be, for example, P-polarized light. Also, the first circularly polarized light may be, for example, right-handed circularly polarized light, and the second circularly polarized light may be, for example, left-handed circularly polarized light.

[0211] However, the display light emitted from the first display panel 5a may be, for example, P-polarized light. Also, the first linearly polarized light may be, for example, P-polarized light, and the second linearly polarized light may be, for example, S-polarized light. Also, the first circularly polarized light may be, for example, left-handed circularly polarized light, and the second circularly polarized light may be, for example, right-handed circularly polarized light. Each phase difference plate and the like converts the polarization state of the incident light so that the light emitted from the first display panel 5a is guided to the touch panel 15 side along the optical path shown in Figure 19, and the second reflective polarizer 18b transmits or reflects the incident light.

[0212] Linearly polarized display light emitted from the first display panel 5a may be converted into first circularly polarized light by passing through the first phase difference plate 16a, passing through the first semi-transparent mirror 10a, and being guided to the second reflective polarizer plate 18b. The second reflective polarizer plate 18b may transmit first circularly polarized light and reflect second circularly polarized light. Therefore, first circularly polarized light incident on the second reflective polarizer plate 18b may pass through the second reflective polarizer plate 18b and be guided to the reflector plate 19.

[0213] The first reflector 19a may transmit second-circularly polarized light and reflect first-circularly polarized light. Similarly, the second reflector 19b may transmit first-circularly polarized light and reflect second-circularly polarized light. Therefore, first-circularly polarized light incident on reflector 19 may be reflected at the reflective surface 195a and led to the second reflective polarizer 18b.

[0214] In Figure 19, the first reflector 19a may be positioned on the opposite side of the second reflector 19b from the second polarizing plate 18b. Therefore, the first circularly polarized light incident on the reflector 19 may pass through the second reflector 19b, be reflected at the reflective surface 195a, pass through the second reflector 19b again, and be guided to the second polarizing plate 18b.

[0215] Light that is first circularly polarized upon the second reflective polarizer 18b may pass through the second reflective polarizer 18b and be guided to the first semi-transparent mirror 10a. Light that is first circularly polarized upon the first semi-transparent mirror 10a may be converted into light that is second circularly polarized by reflection at the first reflective surface 105a and guided to the second reflective polarizer 18b. Light that is second circularly polarized upon the second reflective polarizer 18b may be reflected at the first optical surface 185 and guided to the touch panel 15.

[0216] Next, an example of the propagation of light emitted from the second display panel 5b will be described. The display light emitted from the second display panel 5b may be, for example, P-polarized light. However, the display light emitted from the second display panel 5b may also be, for example, S-polarized light. Each phase difference plate and the like converts the polarization state of the incident light so that the light emitted from the second display panel 5b is guided to the touch panel 15 side along the optical path shown in Figure 19, and the second reflective polarizer 18b transmits or reflects the incident light.

[0217] Linearly polarized display light emitted from the second display panel 5b may be converted into second circularly polarized light by passing through the third phase difference plate 16c, passing through the second semi-transparent mirror 10b, and being guided to the second reflective polarizer plate 18b. The second circularly polarized light incident on the second reflective polarizer plate 18b may be reflected at the second optical surface 186 and guided to the reflector plate 19. The second circularly polarized light incident on the reflector plate 19 may be reflected at the reflective surface 195b and guided to the second reflective polarizer plate 18b.

[0218] The first reflector 19a may be positioned closer to the second polarizing plate 18b than the second reflector 19b. In this case, the second circularly polarized light incident on the reflector 19 may pass through the first reflector 19a, be reflected at the reflective surface 195b, pass through the first reflector 19a again, and be guided to the second polarizing plate 18b.

[0219] Light of second circular polarization incident on the second reflective polarizer 18b may be reflected at the second optical surface 186 and guided to the second semi-transparent mirror 10b. Light of second circular polarization incident on the second semi-transparent mirror 10b may be converted to light of first circular polarization by reflection at the second reflective surface 105b and guided to the second reflective polarizer 18b. Light of first circular polarization incident on the second reflective polarizer 18b may pass through the second reflective polarizer 18b and guided to the touch panel 15.

[0220] Thus, the second reflective polarizing plate 18b may transmit light emitted from the first display panel 5a, which has passed through the first phase difference plate 16a and the first semi-transparent mirror 10a, as first circularly polarized light and guide it toward the reflector 19. Then, the light reflected by the reflector 19 may be transmitted as first circularly polarized light and guided toward the first semi-transparent mirror 10a, and the light reflected by the first semi-transparent mirror 10a may be reflected as second circularly polarized light and guided toward the touch panel 15.

[0221] Alternatively, the second reflective polarizing plate 18b may reflect light emitted from the second display panel 5b, which has passed through the third phase difference plate 16c and the second semi-transparent mirror 10b, as second circularly polarized light and guide it toward the reflector plate 19. Then, the light reflected by the reflector plate 19 may be reflected as second circularly polarized light and guided toward the second semi-transparent mirror 10b, and the light reflected by the second semi-transparent mirror 10b may be transmitted as first circularly polarized light and guided toward the touch panel 15.

[0222] Therefore, the display system 111B allows the viewer 102 to view the first image 9a and the second image 9b formed by the optical system 6 using the second reflective polarizer 18b. Furthermore, because the second reflective polarizer 18b reflects light incident from the first display panel 5a side and guides it towards the touch panel 15 side, the first image 9a can be viewed by the viewer 102 even in a configuration where the first display panel 5a is not positioned facing the touch panel 15 side. In addition, because the second reflective polarizer 18b transmits light incident from the second display panel 5b side and guides it towards the touch panel 15 side, the optical system 6 can easily form an image such that at least a portion of the first image 9a and at least a portion of the second image 9b overlap.

[0223] In this embodiment, as described above, the reflector 19 may include a first reflector 19a and a second reflector 19b. In this case, the second reflective polarizer 18b may emit from the first display panel 5a, transmit light that has passed through the first phase difference plate 16a and the first semi-transparent mirror 10a as first circularly polarized light, and guide it toward the first reflector 19a. Then, it may transmit the light reflected by the first reflector 19a as first circularly polarized light and guide it toward the first semi-transparent mirror 10a. Alternatively, the second reflective polarizer 18b may emit from the second display panel 5b, reflect light that has passed through the third phase difference plate 16c and the second semi-transparent mirror 10b as second circularly polarized light and guide it toward the second reflector 19b. Then, it may reflect the light reflected by the second reflector 19b as second circularly polarized light and guide it toward the second semi-transparent mirror 10b. The display system 111B can achieve the above-described effects even in a configuration that includes a first reflector 19a and a second reflector 19b.

[0224] In this embodiment, the focal length of the first semi-transparent mirror 10a may be shorter than the first optical path length. Also, the focal length of the second semi-transparent mirror 10b may be longer than the second optical path length. In this case, the optical system 6 can form a real image of the first image 9a and a virtual image of the second image 9b. As shown in Figure 19, for example, the optical system 6 can form the first image 9a on the touch panel 15 side and the second image 9b on the side of the second display panel 5b opposite to the touch panel 15.

[0225] [Embodiment 13] Figure 20 is a schematic cross-sectional view showing the configuration of a display system 111A according to Embodiment 13 of the present disclosure. The display system 111A shown in Figure 20 may differ from the display system 111A shown in Figure 18 in that it includes a viewing window 52 instead of a touch panel 15. However, the display system 111A shown in Figure 20 may also include a touch panel 15, and the opening 4 may not have any components. Furthermore, the display system 111A shown in Figure 20 may differ from the display system 111A shown in Figure 18 in that it images at least the first image 9a at a position different from the position where the display system 111A shown in Figure 18 images.

[0226] In this embodiment, the focal length of the first semi-transparent mirror 10a may be longer than the first optical path length. Also, the focal length of the second semi-transparent mirror 10b may be longer than the second optical path length. In this case, the optical system 6 can form virtual images as the first image 9a and the second image 9b.

[0227] As shown in Figure 20, the optical system 6 can image the first image 9a behind the first display panel 5a, i.e., on the side of the second display panel 5b, when the first display panel 5a is positioned so that it faces the viewing window 52 while maintaining the first optical path length. As shown in Figure 20, the optical system 6 can also image the first image 9a on the opposite side of the second display panel 5b from the viewing window 52. Furthermore, the optical system 6 can also image the second image 9b on the opposite side of the second display panel 5b from the viewing window 52. Therefore, a method of using the display system 111A that takes into account the difference in the imaging positions of the first image 9a and the second image 9b can be constructed. Thus, the versatility of the display system 111A can be improved. For example, the first image 9a may show the scale of a speed meter indicating the speed of a moving object equipped with the display system 111A, and the second image 9b may show the needle of the speed meter.

[0228] The size or width of the first image 9a and the second image 9b may be the same or different. The size of the first image 9a may be larger or smaller than the size of the second image 9b. The width of the first image 9a may be larger or smaller than the width of the second image 9b. Here, width may be the length in at least one direction of the X-axis, Y-axis, or Z-axis. As shown in Figure 20, the first image 9a may be imaged behind the second image 9b in the Z-axis direction. The first image 9a may be imaged in front of the second image 9b in the Z-axis direction. The first image 9a may include a portion that is imaged in front of the second image 9b and a portion that is imaged behind the second image 9b in the Z-axis direction. The first image 9a may also be imaged so as to intersect with at least a part of the second image 9b. For example, the first image 9a may be imaged so as to intersect with at least a part of the second image 9b when viewed from the X-axis direction. The first image 9a may include a portion that is imaged at the same position as the second image 9b in the Z-axis direction and a portion that is imaged at a different position.

[0229] Furthermore, since the optical system 6 forms the first image 9a and the second image 9b at the positions described above, it is easy to form relatively large first image 9a and second image 9b. Therefore, the visibility of the first image 9a and the second image 9b can be improved. Moreover, the optical system 6 may form the first image 9a and the second image 9b such that at least a portion of the first image 9a and at least a portion of the second image 9b overlap. As a result, a relatively large and deep image 9 can be made visible to the viewer 102.

[0230] For example, if the focal length of the first semi-transparent mirror 10a is 200 mm and the first optical path length is 150 mm, the distance from the first display panel 5a to the first image 9a can be determined to be 600 mm, and the magnification of the first image 9a can be determined to be 4 times. Also, for example, if the focal length of the second semi-transparent mirror 10b is 100 mm and the second optical path length is 75 mm, the distance from the second display panel 5b to the second image 9b can be determined to be 300 mm, and the magnification of the second image 9b can be determined to be 4 times.

[0231] As another example, if the focal length of the first semi-transparent mirror 10a is 300 mm and the first optical path length is 150 mm, the distance from the first display panel 5a to the first image 9a can be determined to be 300 mm, and the magnification of the first image 9a can be determined to be 2 times. Also, if the focal length of the second semi-transparent mirror 10b is 150 mm and the second optical path length is 75 mm, the distance from the second display panel 5b to the second image 9b can be determined to be 150 mm, and the magnification of the second image 9b can be determined to be 2 times.

[0232] In the two examples above, the focal length of the first semi-transparent mirror 10a is longer than the first optical path length, and the focal length of the second semi-transparent mirror 10b is longer than the second optical path length. Therefore, the first image 9a and the second image 9b are virtual images and may be positioned, for example, on the opposite side of the viewing window 52 from the second display panel 5b, as shown in Figure 20.

[0233] The above values ​​for focal length, first optical path length, and second optical path length are merely examples. By appropriately adjusting the above values ​​for focal length, first optical path length, and second optical path length, the imaging position and size of the first image 9a and second image 9b, which are virtual images, can be changed.

[0234] [Embodiment 14] Figure 21 is a schematic cross-sectional view showing the configuration of a display system 111B according to Embodiment 14 of the present disclosure. The display system 111B shown in Figure 21 may differ from the display system 111B shown in Figure 19 in that it includes a viewing window 52 instead of a touch panel 15. However, the display system 111B shown in Figure 21 may also include a touch panel 15, and the opening 4 may not have any components. Furthermore, the display system 111B shown in Figure 21 may differ from the display system 111B shown in Figure 19 in that it images at least the first image 9a at a position different from the position where the display system 111B shown in Figure 19 images.

[0235] Specifically, the focal length of the first semi-transparent mirror 10a may be longer than the first optical path length. Also, the focal length of the second semi-transparent mirror 10b may be longer than the second optical path length. In this case, the optical system 6 can form virtual images as the first image 9a and the second image 9b. As shown in Figure 21, the optical system 6 can form images of the first image 9a and the second image 9b, for example, behind the second display panel 5b.

[0236] [Embodiment 15] Figure 22 is a schematic cross-sectional view showing the configuration of the display system 111C according to Embodiment 15 of the present disclosure. The display system 111C according to this embodiment may be an example of the display system 100A. The display system 111B shown in Figure 19 may include a first reflector 19a and a second reflector 19b as the reflector 19. On the other hand, the display system 111C of this embodiment may include a reflector 17 as the reflector 19. In the display system 111C of this embodiment, a viewing window 52 may be provided instead of the touch panel 15, or there may be no member provided in the opening 4.

[0237] Furthermore, in the display system 111C of this embodiment, an example is given in which the first image 9a is formed as a real image on the touch panel 15 side, and the second image 9b is formed as a virtual image behind the second display panel 5b. That is, the example is given in which the focal length of the first semi-transparent mirror 10a is shorter than the first optical path length, and the focal length of the second semi-transparent mirror 10b is longer than the second optical path length. However, the display system 111C can also be applied in which the first image 9a and the second image 9b are formed as virtual images behind the second display panel 5b, that is, in which case the focal length of the first semi-transparent mirror 10a is longer than the first optical path length, and the focal length of the second semi-transparent mirror 10b is longer than the second optical path length.

[0238] The display system 111C may include a fifth phase difference plate 16e between the reflector 17 and the second reflective polarizing plate 18b. The fifth phase difference plate 16e may be integrated with the reflector 17 or may be located separately from the reflector 17. The fifth phase difference plate 16e may be a quarter-wave plate, or it may be a different type of wave plate, or a combination thereof. The fifth phase difference plate 16e may be a film-like material.

[0239] Next, we will describe an example of the propagation of light emitted from the first display panel 5a and the propagation of light emitted from the second display panel 5b. Here, we will only describe the differences from the display system 111B shown in Figure 19.

[0240] With respect to the light emitted from the first display panel 5a, in the example shown in Figure 22, the first circularly polarized light that has passed through the first semi-transparent mirror 10a and the second reflective polarizer 18b may be converted into first linearly polarized light by passing through the fifth phase difference plate 16e and guided to the reflector 17. The first linearly polarized light incident on the reflector 17 may be reflected at the reflective surface 175 and guided to the fifth phase difference plate 16e. The first linearly polarized light incident on the fifth phase difference plate 16e may be converted into first circularly polarized light by passing through the fifth phase difference plate 16e and guided to the second reflective polarizer 18b.

[0241] Furthermore, with respect to the light emitted from the second display panel 5b, in the example shown in Figure 22, the second circularly polarized light that passes through the second semi-transparent mirror 10b and is reflected by the second optical surface 186 may be converted into second linearly polarized light by passing through the fifth phase difference plate 16e and guided to the reflecting mirror 17. The second linearly polarized light incident on the reflecting mirror 17 may be reflected by the reflective surface 175 and guided to the fifth phase difference plate 16e. The second linearly polarized light incident on the fifth phase difference plate 16e may be converted into second circularly polarized light by passing through the fifth phase difference plate 16e and guided to the second reflective polarizer 18b.

[0242] For example, the positional relationship between the first phase difference plate 16a and the fifth phase difference plate 16e may be defined such that when the first phase difference plate 16a and the fifth phase difference plate 16e are viewed along the Y-axis, the lagging axis of the fifth phase difference plate 16e is perpendicular or parallel to the lagging axis of the first phase difference plate 16a. Furthermore, the positional relationship between the third phase difference plate 16c and the fifth phase difference plate 16e may be defined such that when the third phase difference plate 16c is viewed along the Z-axis, the lagging axis of the third phase difference plate 16c is perpendicular or parallel to the lagging axis of the fifth phase difference plate 16e when the fifth phase difference plate 16e is viewed along the Y-axis.

[0243] Thus, even in the display system 111C, which has one reflector 19 called a reflector 17, the light emitted from the first display panel 5a and the second display panel 5b can be guided to the touch panel 15. In other words, the display system 111C can guide the light emitted from the first display panel 5a and the second display panel 5b to the touch panel 15, just like the display system 111B, which has two reflectors 19, a first reflector 19a and a second reflector 19b.

[0244] [Embodiment 16] For example, the above describes display systems 100A and 100B that include a first display panel 5a and a second display panel 5b, but the invention is not limited to these. For example, in this disclosure, a device that does not include a first display panel 5a and a second display panel 5b may include an optical system 6.

[0245] For example, as shown in Figure 17, the housing 1 of the display systems 100A and 100B may include a first display panel mounting section 50a and a second display panel mounting section 50b. The first display panel mounting section 50a may be capable of mounting the first display panel 5a. The second display panel mounting section 50b may be capable of mounting the second display panel 5b.

[0246] The first display panel mounting section 50a may be located on a part of the wall surface of the housing 1, or it may be located inside the housing 1. In this case, the first display panel 5a may be located inside the housing 1. Alternatively, the first display panel mounting section 50a may be located outside the housing 1. That is, the first display panel 5a may be located outside the housing 1. In this case, the housing 1 may have an opening in which a part of the wall surface is cut out. The first display panel mounting section 50a may be positioned relative to the housing 1 such that the display light emitted from the first display panel 5a installed in the first display panel mounting section 50a is guided into the inside of the housing 1 through the opening. The first display panel mounting section 50a may be connected to the outer wall of the housing 1, or it may be connected to the outer wall of the housing 1 such that it closes at least a part of the opening.

[0247] Furthermore, the second display panel mounting section 50b may be located on a part of the wall surface of the housing 1, or it may be located inside the housing 1. In this case, the second display panel 5b may be located inside the housing 1. Alternatively, the second display panel mounting section 50b may be located outside the housing 1. That is, the second display panel 5b may be located outside the housing 1. In this case, the housing 1 may have an opening in which a part of the wall surface is cut out. The second display panel mounting section 50b may be positioned relative to the housing 1 such that the display light emitted from the second display panel 5b installed on the second display panel mounting section 50b is guided into the inside of the housing 1 through the opening. The second display panel mounting section 50b may be connected to the outer wall of the housing 1, or it may be connected to the outer wall of the housing 1 such that it closes at least a part of the opening.

[0248] A light-transmitting member may be placed in the above-mentioned opening, and this member may be, for example, glass or resin.

[0249] For example, Figure 17 shows display systems 100A and 100B, which are devices equipped with an optical system 6, in which a first display panel 5a and a second display panel 5b are installed in a first display panel installation section 50a and a second display panel installation section 50b, respectively. However, a device equipped with an optical system 6 may also be a device in which a first display panel 5a and a second display panel 5b are not installed in the first display panel installation section 50a and the second display panel installation section 50b, respectively.

[0250] In this case, the device may be a display panel housing device 120 having a housing 1 that includes a viewing section, an optical system 6, a first display panel mounting section 50a on which a first display panel 5a can be installed, and a second display panel mounting section 50b on which a second display panel 5b can be installed. The display panel housing device 120 may be a device that is not worn by the user.

[0251] In the display panel housing device 120, the configurations of the display systems 100A and 100B of each embodiment described above may also be realized. That is, the positions of the first display panel installation section 50a and the second display panel installation section 50b of the display panel housing device 120 may be defined such that when the first display panel 5a is installed in the first display panel installation section 50a and the second display panel 5b is installed in the second display panel installation section 50b, the configurations of each embodiment described above are achieved.

[0252] Furthermore, the housing 1 of the display panel housing device 120 may have an opening, through which the first display panel 5a and the second display panel 5b can be inserted. In this case, the display panel housing device 120 may have the same configuration as the display systems 100A and 100B, except that the housing 1 has an opening and the first display panel 5a and the second display panel 5b can be inserted from the outside. The opening into which the first display panel 5a can be inserted and the opening into which the second display panel 5b can be inserted may be located at different positions on the housing 1, or they may be located in common on the housing 1.

[0253] [Embodiment 17] Figure 23 is a schematic diagram illustrating the configuration of the display system 130 of the present disclosure. As shown in Figure 23, the display system 100 of the present disclosure can be installed in a first housing 131 having a first viewing section 132, and may also have a second housing 115 having a second viewing section 116. The display system 130 of the present disclosure may also have a first housing 131 having a first viewing section 132, and a second housing 115 installed inside the first housing 131 and having a second viewing section 116.

[0254] The display systems 100 and 130 of this disclosure may include a first display panel 5a located within a second housing 115 and displaying a first display image 7a, and a second display panel 5b located within the second housing 115 and displaying a second display image 7b. The display systems 100 and 130 of this disclosure may also include an optical system 6 located within the second housing 115 that images a first image 9a based on the first display image 7a and a second image 9b based on the second display image 7b. In this case, the display system 100 of this disclosure may be the display system 100A of this disclosure. The display systems 100 and 130 of this disclosure may also include an optical system 6 located within the second housing 115 that images a first image 9a based on the first display image 7a. In this case, the display system 100 of this disclosure may be the display system 100B of this disclosure. In other words, the display system 130 of this disclosure may be a display system comprising a display system 100A that forms a first image 9a and a second image 9b, or a display system comprising a display system 100B that forms a first image 9a.

[0255] The first viewing section 132 may function to allow the interior of the first housing 131 to be viewed from the outside of the first housing 131. The first housing 131 may have a first window (aperture) that transmits light emitted from the optical system 6. The first housing 131 may have a first window that transmits light emitted from the first display panel 5a or the second display panel 5b. The first window may function as the first viewing section 132.

[0256] The first housing 131 may have a member positioned in the first window that makes the interior of the first housing 131 visible from the outside of the first housing 131. The first housing 131 may have a member positioned in the first window that transmits at least a portion of the light emitted from the first display panel 5a and at least a portion of the light emitted from the second display panel 5b. The first housing 131 may have a light-transmitting plate positioned in the first window. The light-transmitting plate may transmit light emitted from the optical system 6. The light-transmitting plate may at least partially block the first window. The light-transmitting plate may be made of, for example, glass, resin, etc. The member positioned in the first window that makes the interior of the first housing 131 visible from the outside of the first housing 131 may function as a first viewing section. This member may be, for example, a light-transmitting plate or at least one member of the optical system 6. Also, a member positioned in the first window that transmits light emitted from the optical system 6 may function as a first viewing section. The component in question may be, for example, a light-transmitting plate. Furthermore, a touch panel 15 may be placed in the first window. In this case, the touch panel 15 may function as the first viewing window.

[0257] The second viewing section 116 may function to allow the interior of the second housing 115 to be viewed from the outside of the second housing 115. The second housing 115 may have a second window (aperture) that transmits light emitted from the optical system 6. The second housing 115 may have a second window that transmits light emitted from the first display panel 5a or the second display panel 5b. The second window may function as the second viewing section 116.

[0258] The second housing 115 may have a member positioned in the second window that allows the interior of the second housing 115 to be viewed from the outside of the second housing 115. The second housing 115 may have a member positioned in the second window that transmits at least a portion of the light emitted from the first display panel 5a and at least a portion of the light emitted from the second display panel 5b. The second housing 115 may have a light-transmitting plate positioned in the second window. The light-transmitting plate may transmit light emitted from the optical system 6. The light-transmitting plate may at least partially block the second window. The light-transmitting plate may be made of, for example, glass, resin, etc. The light-transmitting plate may be the viewing window 52 described above. In addition, at least one member of the optical system 6 may be positioned in the second window of the second housing 115. This member may be, for example, a polarizer such as a reflective polarizer or an absorbing polarizer, a phase difference plate, a semi-transparent mirror, etc. In this case, the second window of the second housing 115 may have both at least one component of the optical system 6 and a light-transmitting plate, or it may have only one of them. A component that makes the interior of the second housing 115 visible from the outside of the second housing 115, which is placed in the second window, may function as a second viewing section 116. This component may be, for example, a light-transmitting plate or at least one component of the optical system. A component that transmits at least a portion of the light emitted from the first display panel 5a and at least a portion of the light emitted from the second display panel 5b, which is placed in the second window, may function as a second viewing section 116. This component may be, for example, a light-transmitting plate or at least one component of the optical system. A touch panel 15 may also be placed in the second window. In this case, the touch panel 15 may function as a second viewing window. That is, the second viewing section 116 may function as the viewing section described above.

[0259] The display system 100 of this disclosure may consist only of a second housing 115 in which a first display panel 5a, a second display panel 5b, and an optical system 6 are arranged. Alternatively, the display system 130 of this disclosure may be configured by installing the second housing 115 inside a first housing 131. For example, the display system 130 for a digital rearview mirror or the like may be configured by installing the second housing 115, in which the first display panel 5a, the second display panel 5b, and the optical system 6 are arranged, inside the housing of a digital rearview mirror or the like. Furthermore, the display system 130 of this disclosure may have an opening in the first housing 131, allowing the second housing 115 to be inserted through the opening.

[0260] Furthermore, in the display systems 100 and 130 of this disclosure, when the inside of the second housing 115 is viewed from the second viewing unit 116, the first image 9a and at least a portion of the second image 9b may be positioned to overlap. Furthermore, in the display system 130 of this disclosure, when the inside of the second housing 115 is viewed from the second viewing unit 116 via the first viewing unit 132, the first image 9a and at least a portion of the second image 9b may be positioned to overlap.

[0261] The shapes of the first housing 131 and the second housing 115 are not particularly limited. For example, two housings 1 may be prepared, and the two housings 1 may be designated as the first housing 131 and the second housing 115, respectively, and the windows (openings 4) of the two housings 1 may be designated as the first viewing section 132 and the second viewing section 116, respectively. Alternatively, housing 1 may be designated as the second housing 115, and the window of housing 1 may be designated as the second viewing section 116. In this case, the housing in which housing 1, which is the second housing 115, can be installed may be designated as the first housing 131. Alternatively, housing 1 may be designated as the first housing 131, and the window of housing 1 may be designated as the first viewing section 132. In this case, the housing in which housing 1, which is the first housing 131, can be installed may be designated as the second housing 115.

[0262] [Embodiment 18] Figure 24 is a schematic cross-sectional view showing the configuration of a display system 111D according to Embodiment 18 of the present disclosure. The display system 111D according to this embodiment may be an example of the display system 100A. The display system 111D may differ from the display system 111A shown in Figure 18 in the following respects: In the display system 111D, the first display panel 5a and the first semi-transparent mirror 10a may be located on the second optical surface 186 side, and the reflecting mirror 17 may not be provided. Also, the display system 111D may not be provided with the first phase difference plate 16a and the second phase difference plate 16b.

[0263] Furthermore, the display system 111D may differ from the display system 111A shown in Figure 18 in that it has a viewing window 52 instead of a touch panel 15. However, the display system 111D may also have a touch panel 15, and the opening 4 may not have any components.

[0264] The same information as that described in Embodiment 11 using Figure 18 will be omitted from this embodiment. However, in this embodiment, the touch panel 15 described in the description of Embodiment 11 may be read as the viewing window 52.

[0265] The first reflective polarizer 18a may have a first optical surface 185 facing the viewing window 52 and a second optical surface 186 facing the opposite side of the first optical surface 185. As shown in Figure 24, the first reflective polarizer 18a may be positioned between the second display panel 5b and the viewing window 52. When the display system 111D is placed on a horizontal plane, if the upward direction is the +Y axis, then in the display system 111D, the second display panel 5b may be located on the housing 1 on the side opposite to the viewing window 52. The first display panel 5a may be located on the upper side of the housing 1. The first reflective polarizer 18a may be positioned such that the first optical surface 185 faces the viewing window 52 and the second optical surface 186 faces the first display surface 55a and the second display surface 55b.

[0266] The first semi-transmissive mirror 10a is positioned between the first display panel 5a and the first reflective polarizing plate 18a, and may transmit light incident from the first display panel 5a side and reflect light incident from the first reflective polarizing plate 18a side. In the present embodiment, the first semi-transmissive mirror 10a may be a plane mirror with the first reflective surface 105a having a planar shape. The first reflective surface 105a may be positioned on the second optical surface 186 side.

[0267] The first semi-transmissive mirror 10a may be a reflecting mirror having a curved surface shape on at least a part of the first reflective surface 105a. The first semi-transmissive mirror 10a may have a function of condensing or converging light. Specifically, the first semi-transmissive mirror 10a may have a function of condensing or converging the light incident on and reflected by the first semi-transmissive mirror 10a. For example, the first semi-transmissive mirror 10a may be a concave mirror with the first reflective surface 105a being concave. Also, the first semi-transmissive mirror 10a may have a function of reflecting and diverging light. Specifically, the first semi-transmissive mirror 10a may have a function of reflecting and diverging the light incident on the first semi-transmissive mirror 10a. For example, the first semi-transmissive mirror 10a may be a convex mirror with the first reflective surface 105a being convex. Also, the first semi-transmissive mirror 10a may be configured to include a holographic optical element or may have a surface shape having a Fresnel shape.

[0268] Next, an example of the progress of the light emitted from the first display panel 5a will be described. The display light emitted from the first display panel 5a may be, for example, light of P polarization. Also, the light of the first linearly polarized light may be, for example, light of S polarization, and the light of the second linearly polarized light may be, for example, light of P polarization. Also, the light of the first circularly polarized light may be, for example, light of right-handed circular polarization, and the light of the second circularly polarized light may be, for example, light of left-handed circular polarization.

[0269] However, the display light emitted from the first display panel 5a may be, for example, light of S polarization. Also, the light of the first linearly polarized light may be, for example, light of P polarization, and the light of the second linearly polarized light may be, for example, light of S polarization. Further, the light of the first circularly polarized light may be, for example, light of left-handed circular polarization, and the light of the second circularly polarized light may be, for example, light of right-handed circular polarization. A retardation plate or the like may convert the polarization state of the incident light so that the light emitted from the first display panel 5a is guided toward the viewing window 52 along the optical path shown in FIG. 24, and the first reflective polarizing plate 18a may transmit or reflect the incident light.

[0270] The linearly polarized display light emitted from the first display panel 5a may pass through the first half-transmissive mirror 10a and be guided to the first reflective polarizing plate 18a as the second linearly polarized light. The first reflective polarizing plate 18a may transmit the light of the first linearly polarized light and reflect the light of the second linearly polarized light. Therefore, the light of the second linearly polarized light incident on the first reflective polarizing plate 18a may be reflected at the second optical surface 186 and be guided to the fourth retardation plate 16d.

[0271] The light of the second linearly polarized light incident on the fourth retardation plate 16d may be converted into the light of the second circularly polarized light by passing through the fourth retardation plate 16d and be guided to the second half-transmissive mirror 10b. The light of the second circularly polarized light incident on the second half-transmissive mirror 10b may be converted into the light of the first circularly polarized light by being reflected at the second reflective surface 105b and be guided to the fourth retardation plate 16d. The light of the first circularly polarized light incident on the fourth retardation plate 16d may be converted into the light of the first linearly polarized light by passing through the fourth retardation plate 16d and be guided to the first reflective polarizing plate 18a. The light of the first linearly polarized light incident on the first reflective polarizing plate 18a may pass through the first reflective polarizing plate 18a and be guided to the viewing window 52.

[0272] Next, an example of the propagation of light emitted from the second display panel 5b will be described. The display light emitted from the second display panel 5b may be, for example, P-polarized light. However, the display light emitted from the second display panel 5b may also be, for example, S-polarized light. The phase difference plate or the like converts the polarization state of the incident light so that the light emitted from the second display panel 5b is guided towards the viewing window 52 side along the optical path shown in Figure 24, and the first reflective polarizer 18a transmits or reflects the incident light.

[0273] Linearly polarized display light emitted from the second display panel 5b may be converted into second circularly polarized light by passing through the third phase difference plate 16c, passing through the second semi-transparent mirror 10b, and being guided to the fourth phase difference plate 16d. Second circularly polarized light incident on the fourth phase difference plate 16d may be converted into second linearly polarized light by passing through the fourth phase difference plate 16d, and being guided to the first reflective polarizer 18a. Second linearly polarized light incident on the first reflective polarizer 18a may be reflected at the second optical surface 186 and guided to the first semi-transparent mirror 10a. Second linearly polarized light incident on the first semi-transparent mirror 10a may be reflected at the first reflective surface 105a and guided to the first reflective polarizer 18a.

[0274] Light of the second linear polarization incident on the first reflective polarizer 18a may be reflected at the second optical surface 186 and guided to the fourth phase difference plate 16d. Light of the second linear polarization incident on the fourth phase difference plate 16d may be converted into light of the second circular polarization by passing through the fourth phase difference plate 16d and guided to the second semitransparent mirror 10b.

[0275] The second circularly polarized light incident on the second semi-transparent mirror 10b may be converted to first circularly polarized light by reflection at the second reflective surface 105b and guided to the fourth phase difference plate 16d. The first circularly polarized light incident on the fourth phase difference plate 16d may be converted to first linearly polarized light by passing through the fourth phase difference plate 16d and guided to the first reflective polarizer 18a. The first linearly polarized light incident on the first reflective polarizer 18a may be passed through the first reflective polarizer 18a and guided to the viewing window 52.

[0276] Thus, the first reflective polarizing plate 18a may reflect the light emitted from the first display panel 5a and transmitted through the first semi-transparent mirror 10a as second linearly polarized light and guide it toward the second semi-transparent mirror 10b. Then, the light reflected by the second semi-transparent mirror 10b and transmitted through the fourth phase difference plate 16d may be transmitted as first linearly polarized light and guided toward the viewing window 52.

[0277] Furthermore, the first reflective polarizing plate 18a may reflect light emitted from the second display panel 5b, which has passed through the third phase difference plate 16c, the second semi-transparent mirror 10b, and the fourth phase difference plate 16d, as second linearly polarized light and guide it towards the first semi-transparent mirror 10a. Then, the light reflected by the first semi-transparent mirror 10a may be reflected as second linearly polarized light and guided towards the second semi-transparent mirror 10b, and the light reflected by the second semi-transparent mirror 10b and passed through the fourth phase difference plate 16d may be transmitted as first linearly polarized light and guided towards the viewing window 52.

[0278] Therefore, the display system 111D can make the first image 9a and the second image 9b visible to the viewer 102 by the first reflective polarizer 18a. Furthermore, even in a configuration where the first display panel 5a is not positioned facing the viewing window 52, ​​the first image 9a can be made visible to the viewer 102. In addition, because the first reflective polarizer 18a transmits light incident from the second display panel 5b side and guides it toward the viewing window 52 side, the optical system 6 can easily form an image such that at least a portion of the first image 9a and at least a portion of the second image 9b overlap.

[0279] Furthermore, the display light emitted from the first display panel 5a may be reflected away from the viewing window 52 by the second optical surface 186, which is located on the opposite side of the viewing window 52. This reduces the possibility that the display light emitted from the first display panel 5a will be reflected by the first optical surface 185, which is located on the viewing window 52 side. Consequently, the possibility that the display light emitted from the first display panel 5a will directly pass through the viewing window 52 and be seen by the viewer 102 together with the first image 9a is reduced. In other words, the possibility that both the first image 9a and the first display image displayed on the first display panel 5a will be seen by the viewer 102 is reduced. Therefore, the possibility that the visibility of the first image 9a will be reduced is reduced.

[0280] In this embodiment, the focal length of the second semi-transparent mirror 10b may be longer than the first optical path length. Also, the focal length of the second semi-transparent mirror 10b may be longer than the second optical path length. In this case, the optical system 6 can form virtual images as the first image 9a and the second image 9b, just like the optical system 6 shown in Figure 20. However, the focal length of the second semi-transparent mirror 10b may be shorter than the first optical path length. Also, the focal length of the second semi-transparent mirror 10b may be shorter than the second optical path length. In this case, the optical system 6 can form real images as the first image 9a and the second image 9b. By appropriately adjusting the relationship between the focal length of the second semi-transparent mirror 10b and the first optical path length, the optical system 6 may form the first image 9a as a virtual image or as a real image. Furthermore, by appropriately adjusting the relationship between the focal length of the second semi-transparent mirror 10b and the second optical path length, the optical system 6 may form the second image 9b as a virtual image or as a real image. In addition, by appropriately adjusting the focal length, the first optical path length, and the second optical path length, the imaging position and size of the first image 9a and the second image 9b can be changed.

[0281] [Embodiment 19] Figure 25 is a schematic cross-sectional view showing the configuration of the display system 111E according to Embodiment 19 of the present disclosure. The display system 111E according to this embodiment may be an example of the display system 100A. The display system 111E may differ from the display system 111A shown in Figure 18 in the following respects. The display system 111E does not need to include the first semitransparent mirror 10a, the first phase difference plate 16a, and the second phase difference plate 16b.

[0282] Furthermore, the display system 111E may differ from the display system 111A shown in Figure 18 in that it has a viewing window 52 instead of a touch panel 15. However, the display system 111E may also have a touch panel 15, and the opening 4 may not have any components.

[0283] The same information as that described in Embodiment 11 using Figure 18 will be omitted from this embodiment. However, in this embodiment, the touch panel 15 described in the description of Embodiment 11 may be read as the viewing window 52.

[0284] An example of the propagation of light emitted from the first display panel 5a will be described. The display light emitted from the first display panel 5a may be, for example, P-polarized light. Also, the first linearly polarized light may be, for example, S-polarized light, and the second linearly polarized light may be, for example, P-polarized light.

[0285] However, the display light emitted from the first display panel 5a may be, for example, S-polarized light. Also, the first linearly polarized light may be, for example, P-polarized light, and the second linearly polarized light may be, for example, S-polarized light. The first reflective polarizer 18a should reflect the incident light so that the light emitted from the first display panel 5a is guided to the viewing window 52 along the optical path shown in Figure 25.

[0286] Linearly polarized display light emitted from the first display panel 5a may be directly guided to the first reflective polarizer 18a as second linearly polarized light. The first reflective polarizer 18a may transmit the first linearly polarized light and reflect the second linearly polarized light. Therefore, the second linearly polarized light incident on the first reflective polarizer 18a may be reflected at the first optical surface 185 and guided to the viewing window 52.

[0287] Thus, the first reflective polarizer 18a may reflect the light emitted from the first display panel 5a as second linearly polarized light and guide it to the viewing window 52. In the display system 111E, the first reflective polarizer 18a may function as a mirror that reflects the display light emitted from the first display panel 5a, i.e., the first display image, towards the viewing window 52. As described above, since a mirror has the function of projecting an object as a virtual image, the first reflective polarizer 18a that reflects the display light emitted from the first display panel 5a towards the viewing window 52 may also be said to form a first image 9a based on the first display image.

[0288] Further, the first reflective polarizing plate 18a may reflect the light emitted from the second display panel 5b and transmitted through the third retardation plate 16c, the second half mirror 10b, and the fourth retardation plate 16d as the second linearly polarized light and guide it to the mirror 17 side. Then, the light reflected by the mirror 17 is reflected as the second linearly polarized light and guided to the second half mirror 10b side, and the light reflected by the second half mirror 10b and transmitted through the fourth retardation plate 16d is transmitted as the first linearly polarized light and guided to the viewing window 52 side.

[0289] Therefore, in the display system 111E as well, the first image 9a and the second image 9b can be made visible to the viewer 102 by the first reflective polarizing plate 18a. Also, in the display system 111E, even in a configuration where the first display panel 5a is not positioned facing the viewing window 52 side, the first image 9a can be made visible to the viewer 102. Further, the first reflective polarizing plate 18a may reflect the light incident from the first display panel 5a side and guide it to the viewing window 52 side, and transmit the light incident from the second display panel 5b side and guide it to the viewing window 52 side. Thereby, the optical system 6 can easily form an image such that at least a part of the first image 9a and at least a part of the second image 9b overlap.

[0290] Here, when the first image 9a is formed by reflecting the display light emitted from the first display panel 5a by the first half mirror 10a, if the display light is directly emitted from the viewing window 52, the visibility of the first image 9a may be reduced by the display light. In the display system 111E, since the first image 9a is formed by the first reflective polarizing plate 18a directly reflecting the display light emitted from the first display panel 5a, the possibility of the visibility of the first image 9a being reduced by the display light can be reduced.

[0291] Also, the display system 111E does not necessarily need to include the first half mirror 10a. Therefore, a part of the display light emitted from the first display panel 5a is not reflected by the first half mirror 10a. Thus, the possibility of the light amount of the first image 9a being reduced can be reduced.

[0292] Furthermore, since the display system 111E does not require the first semi-transparent mirror 10a, the first phase difference plate 16a, and the second phase difference plate 16b, the vertical size of the housing 1 can be reduced. Therefore, the housing 1 can be made more compact.

[0293] In this embodiment, the focal length of the second semi-transparent mirror 10b may be longer than the second optical path length. In this case, the optical system 6 can form a virtual image as the second image 9b. However, the focal length of the second semi-transparent mirror 10b may be shorter than the second optical path length. In this case, the optical system 6 can form a real image as the second image 9b. By appropriately adjusting the relationship between the focal length of the second semi-transparent mirror 10b and the second optical path length, the optical system 6 may form the second image 9b as a virtual image or as a real image. Furthermore, by appropriately adjusting the distance between the first display panel 5a and the first reflective polarizer 18a, the focal length of the second semi-transparent mirror 10b, and the second optical path length, the image position and size of the first image 9a and the second image 9b can be changed.

[0294] [Embodiment 20] Figure 26 is a schematic cross-sectional view showing the configuration of the display system 111F according to Embodiment 20 of the present disclosure. The display system 111F according to this embodiment may be an example of the display system 100A. The display system 111F may differ from the display system 111A shown in Figure 18 in the following respects. The display system 111F may include a third reflective polarizing plate 21.

[0295] Furthermore, the display system 111F may differ from the display system 111A shown in Figure 18 in that it has a viewing window 52 instead of a touch panel 15. However, the display system 111F may also have a touch panel 15, and the opening 4 may not have any components.

[0296] The same information as that described in Embodiment 11 using Figure 18 will be omitted from this embodiment. However, in this embodiment, the touch panel 15 described in the description of Embodiment 11 may be read as the viewing window 52.

[0297] The third reflective polarizer 21 is located between the second phase difference plate 16b and the first reflective polarizer 18a, and may transmit the second linearly polarized light and reflect the first linearly polarized light. However, the third reflective polarizer 21 may transmit the first linearly polarized light and reflect the second linearly polarized light. The structure of the third reflective polarizer 21 may be the same as the structure of the first reflective polarizer 18a.

[0298] An example of the propagation of light emitted from the first display panel 5a will be described. The display light emitted from the first display panel 5a may be, for example, S-polarized light. Also, the first linearly polarized light may be, for example, S-polarized light, and the second linearly polarized light may be, for example, P-polarized light. Also, the first circularly polarized light may be, for example, right-handed circularly polarized light, and the second circularly polarized light may be, for example, left-handed circularly polarized light.

[0299] However, the display light emitted from the first display panel 5a may be, for example, P-polarized light. Also, the first linearly polarized light may be, for example, P-polarized light, and the second linearly polarized light may be, for example, S-polarized light. Also, the first circularly polarized light may be, for example, left-handed circularly polarized light, and the second circularly polarized light may be, for example, right-handed circularly polarized light. The phase difference plate or the like converts the polarization state of the incident light so that the light emitted from the first display panel 5a is guided towards the viewing window 52 side along the optical path shown in Figure 26, and the first reflective polarizer plate 18a reflects the incident light.

[0300] Linearly polarized display light emitted from the first display panel 5a may be converted into first circularly polarized light by passing through the first phase difference plate 16a, passing through the first semi-transparent mirror 10a, and being guided to the second phase difference plate 16b. First circularly polarized light incident on the second phase difference plate 16b may be converted into first linearly polarized light by passing through the second phase difference plate 16b, and being guided to the third reflective polarizer 21.

[0301] The third reflective polarizer 21 may transmit second linearly polarized light and reflect first linearly polarized light. Therefore, first linearly polarized light incident on the third reflective polarizer 21 may be reflected by the third reflective polarizer 21 and guided to the second phase difference plate 16b. First linearly polarized light incident on the second phase difference plate 16b may be converted into first circularly polarized light by passing through the second phase difference plate 16b and guided to the first semi-transparent mirror 10a.

[0302] The first circularly polarized light incident on the first semi-transparent mirror 10a may be converted into second circularly polarized light by reflection at the first reflective surface 105a and guided to the second phase difference plate 16b. The second circularly polarized light incident on the second phase difference plate 16b may be converted into second linearly polarized light by transmission through the second phase difference plate 16b and guided to the third reflective polarizer 21.

[0303] Light of the second linear polarization incident on the third reflective polarizer 21 may pass through the third reflective polarizer 21 and be guided to the first reflective polarizer 18a. Light of the second linear polarization incident on the first reflective polarizer 18a may be reflected at the first optical surface 185 and guided to the viewing window 52.

[0304] Thus, the third reflective polarizing plate 21 may reflect the light emitted from the first display panel 5a, which has passed through the first phase difference plate 16a, the first semi-transparent mirror 10a, and the second phase difference plate 16b, as first linearly polarized light and guide it toward the first semi-transparent mirror 10a. Then, the light reflected by the first semi-transparent mirror 10a and passed through the second phase difference plate 16b may be transmitted as second linearly polarized light and guided toward the first reflective polarizing plate 18a.

[0305] Furthermore, the first reflective polarizing plate 18a may reflect the light transmitted through the third reflective polarizing plate 21 as second linearly polarized light and guide it toward the viewing window 52. Alternatively, the first reflective polarizing plate 18a may reflect the light emitted from the second display panel 5b, transmitted through the third phase difference plate 16c, the second semi-transparent mirror 10b, and the fourth phase difference plate 16d as second linearly polarized light and guide it toward the reflecting mirror 17. Then, the light reflected by the reflecting mirror 17 may be reflected as second linearly polarized light and guided toward the second semi-transparent mirror 10b, and the light reflected by the second semi-transparent mirror 10b and transmitted through the fourth phase difference plate 16d may be transmitted as first linearly polarized light and guided toward the viewing window 52.

[0306] Therefore, in the display system 111F, the first image 9a and the second image 9b can be made visible to the viewer 102 by the first reflective polarizer 18a. Also, in the display system 111F, even in a configuration where the first display panel 5a is not positioned facing the viewing window 52, ​​the first image 9a can be made visible to the viewer 102. Furthermore, the first reflective polarizer 18a may reflect light incident from the first display panel 5a side and guide it towards the viewing window 52 side, and transmit light incident from the second display panel 5b side and guide it towards the viewing window 52 side. This makes it easier for the optical system 6 to form an image such that at least a part of the first image 9a and at least a part of the second image 9b overlap.

[0307] Furthermore, in the display system 111F, the display light emitted from the first display panel 5a and transmitted through the first semi-transparent mirror 10a may be reflected by the third reflective polarizer 21. The light reflected again by the first semi-transparent mirror 10a may then be transmitted through the third reflective polarizer 21 and incident on the first reflective polarizer 18a. This reduces the possibility that the display light will be directly incident on the first reflective polarizer 18a, thus reducing the possibility that the display light will be reflected by the first optical surface 185 located on the viewing window 52 side. Therefore, the possibility that both the first image 9a and the first display image displayed on the first display panel 5a will be visible to the viewer 102 is reduced. As a result, the possibility of reduced visibility of the first image 9a is reduced.

[0308] In this embodiment, the focal length of the first semi-transparent mirror 10a may be longer than the first optical path length. Also, the focal length of the second semi-transparent mirror 10b may be longer than the second optical path length. In this case, the optical system 6 can form virtual images as the first image 9a and the second image 9b, just like the optical system 6 shown in Figure 20. However, the focal length of the first semi-transparent mirror 10a may be shorter than the first optical path length. Also, the focal length of the second semi-transparent mirror 10b may be shorter than the second optical path length. In this case, the optical system 6 can form real images as the first image 9a and the second image 9b. By appropriately adjusting the relationship between the focal length of the first semi-transparent mirror 10a and the first optical path length, the optical system 6 may form the first image 9a as a virtual image or as a real image. Furthermore, by appropriately adjusting the relationship between the focal length of the second semi-transparent mirror 10b and the second optical path length, the optical system 6 may form the second image 9b as a virtual image or as a real image. In addition, by appropriately adjusting the focal length, the first optical path length, and the second optical path length, the imaging position and size of the first image 9a and the second image 9b can be changed.

[0309] [Embodiment 21] Figure 27 is a schematic cross-sectional view showing the configuration of the display system 111G according to Embodiment 21 of the present disclosure. The display system 111G according to this embodiment may be an example of the display system 100A. The display system 111G may differ from the display system 111D shown in Figure 24 in the following respects. The display system 111G may include a third display panel 5c.

[0310] The third display panel 5c may have a third display surface 55c for displaying a third display image. The third display panel 5c may be located inside the housing 1. Alternatively, the third display panel 5c may be located outside the housing 1. In this case, the housing 1 may have an opening in which a part of the wall surface is cut out at a position corresponding to the third display panel 5c. The third display panel 5c may be positioned relative to the housing 1 such that the display light emitted from the third display panel 5c is guided into the housing 1 through the opening. The third display panel 5c may be positioned corresponding to the opening, may be positioned to block at least a part of the opening, and may be connected to the outer wall of the housing 1. A light-transmitting member may be placed in the opening, and this member may be, for example, glass or resin.

[0311] The first reflective polarizer 18a may have a first optical surface 185 on the side of the viewing window 52 and a second optical surface 186 on the opposite side of the first optical surface 185. As shown in Figure 27, the first reflective polarizer 18a may be located between the first display panel 5a and the third display panel 5c, and also between the second display panel 5b and the viewing window 52. When the display system 111G is placed on a horizontal surface, if the upward direction is the +Y axis, then in the display system 111F, the second display panel 5b may be located on the side of the housing 1 opposite to the viewing window 52. The first display panel 5a may be located on the upper side of the housing 1. The third display panel 5c may be located on the bottom side of the housing 1. The first reflective polarizing plate 18a may be positioned such that the first optical surface 185 faces the viewing window 52 and the third display surface 55c, and the second optical surface 186 faces the first display surface 55a and the second display surface 55b.

[0312] Next, an example of the propagation of light emitted from the third display panel 5c will be described. The display light emitted from the third display panel 5c may be, for example, P-polarized light. Also, the first linearly polarized light may be, for example, S-polarized light, and the second linearly polarized light may be, for example, P-polarized light.

[0313] However, the display light emitted from the third display panel 5c may be, for example, S-polarized light. Also, the first linearly polarized light may be, for example, P-polarized light, and the second linearly polarized light may be, for example, S-polarized light. The first reflective polarizer 18a should reflect the incident light so that the light emitted from the first display panel 5a is guided to the viewing window 52 along the optical path shown in Figure 27.

[0314] Linearly polarized display light emitted from the first display panel 5a may be directly guided to the first reflective polarizer 18a as second linearly polarized light. The first reflective polarizer 18a may transmit the first linearly polarized light and reflect the second linearly polarized light. Therefore, the second linearly polarized light incident on the first reflective polarizer 18a may be reflected at the first optical surface 185 and guided to the viewing window 52.

[0315] Thus, the first reflective polarizer 18a may reflect the light emitted from the third display panel 5c as second linearly polarized light and guide it to the viewing window 52. In the display system 111G, the first reflective polarizer 18a may function as a mirror that reflects the display light emitted from the third display panel 5c, i.e., the third display image, towards the viewing window 52. As described above, since a mirror has the function of projecting an object as a virtual image, the first reflective polarizer 18a that reflects the display light emitted from the third display panel 5c towards the viewing window 52 may also be said to form a third image 9c based on the third display image.

[0316] Furthermore, the first reflective polarizing plate 18a may reflect or transmit the light emitted from the first display panel 5a and the light emitted from the second display panel 5b, respectively, as described in Embodiment 18, and guide them towards the viewing window 52.

[0317] Therefore, the display system 111G can make the viewer 102 see the third image 9c in addition to the first image 9a and the second image 9b through the first reflective polarizer 18a. Furthermore, even in a configuration where the first display panel 5a and the third display panel 5c are not positioned facing the viewing window 52, ​​the first image 9a and the third image 9c can be made visible to the viewer 102. In addition, by transmitting the light incident from the second display panel 5b side through the first reflective polarizer 18a and guiding it toward the viewing window 52, ​​the optical system 6 can easily form an image such that at least a portion of the first image 9a and at least a portion of the second image 9b overlap. Furthermore, by reflecting the light incident from the third display panel 5c side through the first reflective polarizer 18a and guiding it toward the viewing window 52, ​​the optical system 6 can easily form an image such that at least a portion of the first image 9a and at least a portion of the third image 9c overlap. Furthermore, it is easier to form an image such that at least a portion of the second image 9b and at least a portion of the third image 9c overlap.

[0318] Furthermore, as described in Embodiment 18, the display light emitted from the first display panel 5a may be reflected away from the viewing window 52 by the second optical surface 186 located on the opposite side of the viewing window 52. This reduces the possibility that both the first image 9a and the first display image displayed on the first display panel 5a may be seen by the viewer 102. Therefore, the possibility of reduced visibility of the first image 9a can be reduced.

[0319] Furthermore, in the display system 111G, the third image 9c may be formed by the first reflective polarizer 18a directly reflecting the display light emitted from the third display panel 5c. In other words, the third image 9c does not have to be formed by reflecting the display light emitted from the third display panel 5c with a semi-transparent mirror. Therefore, the possibility that the visibility of the third image 9c will be reduced due to the display light being emitted from the viewing window 52 can be reduced.

[0320] In this embodiment as well, as described in Embodiment 18, the focal length of the second semi-transparent mirror 10b may be longer or shorter than the first optical path length.

[0321] Furthermore, the imaging position and size of the first image 9a and the second image 9b can be changed by appropriately adjusting the focal length, the first optical path length, and the second optical path length. Also, the imaging position and size of the third image 9c can be changed by appropriately adjusting the distance between the third display panel 5c and the first reflective polarizer 18a.

[0322] [Embodiment 22] Figure 28 is a schematic cross-sectional view showing the configuration of the display system 111H according to Embodiment 22 of the present disclosure. The display system 111H according to this embodiment may be an example of the display system 100A. The display system 111H may differ from the display system 111A shown in Figure 18 in the following respects. The display system 111H may include at least one reflector 19 instead of the reflector 17.

[0323] Furthermore, the display system 111H may differ from the display system 111A shown in Figure 18 in that it has a viewing window 52 instead of a touch panel 15. However, the display system 111H may also have a touch panel 15, and the opening 4 may not have any components.

[0324] The same information as that described in Embodiment 11 using Figure 18 will be omitted from this embodiment. However, in this embodiment, the touch panel 15 described in the description of Embodiment 11 may be read as the viewing window 52.

[0325] As shown in Figure 28, in the display system 111H, the second phase difference plate 16b may be positioned between the first semi-transparent mirror 10a and the first reflective polarizer 18a, along with the first reflective polarizer 18a. Also, the fourth phase difference plate 16d may be positioned between the second semi-transparent mirror 10b and the first reflective polarizer 18a, along with the first reflective polarizer 18a.

[0326] The second phase difference plate 16b and the fourth phase difference plate 16d may be integrated with the first reflective polarizer 18a, or they may be positioned separately from the first reflective polarizer 18a, as long as they are positioned along the first reflective polarizer 18a. For example, the second phase difference plate 16b may be positioned in contact with the first optical surface 185 of the first reflective polarizer 18a, or it may be bonded to the first optical surface 185. Also, for example, the fourth phase difference plate 16d may be positioned in contact with the second optical surface 186 of the first reflective polarizer 18a, or it may be bonded to the second optical surface 186.

[0327] The second phase difference plate 16b is emitted from the first display panel 5a, and the light transmitted through the second phase difference plate 16b should be given the necessary phase difference so that the light transmitted through the first phase difference plate 16a and the second phase difference plate 16b is transmitted through the first reflective polarizer plate 18a. Furthermore, the second phase difference plate 16b is reflected by the first semi-transparent mirror 10a, and the light transmitted through the second phase difference plate 16b should be given the necessary phase difference so that the light transmitted through the second phase difference plate 16b is reflected by the first reflective polarizer plate 18a.

[0328] The fourth phase difference plate 16d is emitted from the second display panel 5b, and the light transmitted through the third phase difference plate 16c and the fourth phase difference plate 16d should be given the necessary phase difference so that the light transmitted through the fourth phase difference plate 16d is reflected by the first reflective polarizer plate 18a. In addition, the fourth phase difference plate 16d is reflected by the second semi-transparent mirror 10b, and the light transmitted through the fourth phase difference plate 16d should be given the necessary phase difference so that the light transmitted through the fourth phase difference plate 16d is transmitted through the first reflective polarizer plate 18a.

[0329] In this embodiment, the fourth phase difference plate 16d is further configured such that the light emitted from the first display panel 5a and reflected by the reflector 19 passes through the first reflective polarizer 18a, thereby providing the necessary phase difference to the light transmitted through the fourth phase difference plate 16d.

[0330] If such a phase difference can be provided, the second phase difference plate 16b and the fourth phase difference plate 16d may be quarter-wave plates, i.e., λ / 4 wave plates, or they may be other wave plates or combinations thereof.

[0331] The reflector 19 may reflect light incident from the side of the first reflective polarizer 18a. As shown in Figure 28, in this embodiment, the display system 111H may include a first reflector 19a and a second reflector 19b as the reflector 19. The first reflector 19a may have a reflective surface 195a, and the second reflector 19b may have a reflective surface 195b.

[0332] Specifically, the first reflector 19a may be a reflective polarizer that transmits second circularly polarized light and reflects first circularly polarized light. The second reflector 19b may be a reflective polarizer that transmits first circularly polarized light and reflects second circularly polarized light. However, the first reflector 19a may be a reflective polarizer that transmits first circularly polarized light and reflects second circularly polarized light. The second reflector 19b may be a reflective polarizer that transmits second circularly polarized light and reflects first circularly polarized light. The first reflector 19a and the second reflector 19b may have the same structure as the second reflective polarizer 18b, and may include, for example, a cholesteric liquid crystal film.

[0333] In Figure 28, the second reflector 19b is located on the inside of the housing 1, i.e., on the side of the first reflective polarizer 18a, relative to the first reflector 19a. However, the design is not limited to this, and the first reflector 19a may be located on the inside of the housing 1, i.e., on the side of the first reflective polarizer 18a, relative to the second reflector 19b. Furthermore, the first reflector 19a may be integrated with the second reflector 19b, or it may be located separately from the second reflector 19b.

[0334] Next, an example of the propagation of light emitted from the first display panel 5a will be described. The display light emitted from the first display panel 5a may be, for example, S-polarized light. Also, the first linearly polarized light may be, for example, S-polarized light, and the second linearly polarized light may be, for example, P-polarized light. Also, the first circularly polarized light may be, for example, right-handed circularly polarized light, and the second circularly polarized light may be, for example, left-handed circularly polarized light.

[0335] However, the display light emitted from the first display panel 5a may be, for example, P-polarized light. Also, the first linearly polarized light may be, for example, P-polarized light, and the second linearly polarized light may be, for example, S-polarized light. Also, the first circularly polarized light may be, for example, left-handed circularly polarized light, and the second circularly polarized light may be, for example, right-handed circularly polarized light. The phase difference plate or the like converts the polarization state of the incident light so that the light emitted from the first display panel 5a is guided towards the viewing window 52 side along the optical path shown in Figure 28, and the first reflective polarizer 18a transmits or reflects the incident light.

[0336] Linearly polarized display light emitted from the first display panel 5a may be converted into first circularly polarized light by passing through the first phase difference plate 16a, passing through the first semi-transparent mirror 10a, and being guided to the second phase difference plate 16b. First circularly polarized light incident on the second phase difference plate 16b may be converted into first linearly polarized light by passing through the second phase difference plate 16b, and being guided to the first reflective polarizer 18a.

[0337] The first reflective polarizer 18a may transmit first linearly polarized light and reflect second linearly polarized light. Therefore, first linearly polarized light incident on the first reflective polarizer 18a may pass through the first reflective polarizer 18a and be guided to the fourth phase difference plate 16d. First linearly polarized light incident on the fourth phase difference plate 16d may be converted into first circularly polarized light by passing through the fourth phase difference plate 16d and guided to the reflector 19.

[0338] The first reflector 19a may transmit second-circularly polarized light and reflect first-circularly polarized light. Similarly, the second reflector 19b may transmit first-circularly polarized light and reflect second-circularly polarized light. Therefore, first-circularly polarized light incident on reflector 19 may be reflected at the reflective surface 195a and led to the first reflective polarizer 18a.

[0339] In Figure 28, the first reflector 19a may be positioned on the opposite side of the second reflector 19b from the first polarizing plate 18a. Therefore, the first circularly polarized light incident on the reflector 19 may pass through the second reflector 19b, be reflected at the reflective surface 195a, pass through the second reflector 19b again, and be guided to the fourth phase difference plate 16d.

[0340] The first circularly polarized light incident on the fourth phase difference plate 16d may be converted to first linearly polarized light by passing through the fourth phase difference plate 16d and guided to the first reflecting polarizer plate 18a. The first linearly polarized light incident on the first reflecting polarizer plate 18a may be converted to first circularly polarized light by passing through the first reflecting polarizer plate 18a and guided to the second phase difference plate 16b. The first linearly polarized light incident on the second phase difference plate 16b may be converted to first circularly polarized light by passing through the second phase difference plate 16b and guided to the first semi-transparent mirror 10a.

[0341] Light of the first circular polarization incident on the first semi-transparent mirror 10a may be converted into light of the second circular polarization by reflection at the first reflective surface 105a and guided to the second phase difference plate 16b. Light of the second circular polarization incident on the second phase difference plate 16b may be converted into light of the second linear polarization by transmission through the second phase difference plate 16b and guided to the first reflective polarizer 18a. Light of the second linear polarization incident on the first reflective polarizer 18a may be reflected at the first optical surface 185 and guided again to the second phase difference plate 16b. Light of the second linear polarization incident on the second phase difference plate 16b may be converted into light of the second circular polarization by transmission through the second phase difference plate 16b and guided to the viewing window 52.

[0342] Next, an example of the propagation of light emitted from the second display panel 5b will be described. The display light emitted from the second display panel 5b may be, for example, P-polarized light. However, the display light emitted from the second display panel 5b may also be, for example, S-polarized light. The phase difference plate or the like converts the polarization state of the incident light so that the light emitted from the second display panel 5b is guided towards the viewing window 52 side along the optical path shown in Figure 28, and the first reflective polarizer 18a transmits or reflects the incident light.

[0343] Linearly polarized display light emitted from the second display panel 5b may be converted into second circularly polarized light by passing through the third phase difference plate 16c, passing through the second semi-transparent mirror 10b, and being guided to the fourth phase difference plate 16d. Second circularly polarized light incident on the fourth phase difference plate 16d may be converted into second linearly polarized light by passing through the fourth phase difference plate 16d, and being guided to the first reflective polarizer plate 18a.

[0344] Light of the second linear polarization incident on the first reflecting polarizer 18a may be reflected at the second optical surface 186 and guided again to the fourth phase difference plate 16d. Light of the second linear polarization incident on the fourth phase difference plate 16d may be converted into light of the second circular polarization by passing through the fourth phase difference plate 16d and guided to the reflector 19. Light of the second circular polarization incident on the reflector 19 may be reflected at the reflective surface 195b and guided to the fourth phase difference plate 16d.

[0345] The first reflector 19a may be positioned closer to the first polarizing plate 18a than the second reflector 19b. In this case, the second circularly polarized light incident on the reflector 19 may pass through the first reflector 19a, be reflected at the reflective surface 195b, pass through the first reflector 19a again, and be guided to the first polarizing plate 18a.

[0346] The second circularly polarized light incident on the fourth phase difference plate 16d may be converted into second linearly polarized light by passing through the fourth phase difference plate 16d and guided to the first reflective polarizer 18a. The second linearly polarized light incident on the first reflective polarizer 18a may be reflected at the second optical surface 186 and guided again to the fourth phase difference plate 16d. The second linearly polarized light incident on the fourth phase difference plate 16d may be converted into second circularly polarized light by passing through the fourth phase difference plate 16d and guided to the second semi-transparent mirror 10b.

[0347] Light of second circular polarization incident on the second semi-transparent mirror 10b may be converted to light of first circular polarization by reflection at the second reflective surface 105b and guided to the fourth phase difference plate 16d. Light of first circular polarization incident on the fourth phase difference plate 16d may be converted to light of first linear polarization by passing through the fourth phase difference plate 16d and guided to the first reflective polarizer 18a. Light of first linear polarization incident on the first reflective polarizer 18a may be guided to the second phase difference plate 16b by passing through the first reflective polarizer 18a. Light of first linear polarization incident on the second phase difference plate 16b may be converted to light of first circular polarization by passing through the second phase difference plate 16b and guided to the viewing window 52.

[0348] Thus, the first reflective polarizing plate 18a may transmit light emitted from the first display panel 5a, which has passed through the first phase difference plate 16a, the first semi-transparent mirror 10a, and the second phase difference plate 16b, as first linearly polarized light and guide it toward the reflector 19. Then, the light reflected by the reflector 19 and transmitted through the fourth phase difference plate 16d may be transmitted as first linearly polarized light and guided toward the first semi-transparent mirror 10a. Then, the light reflected by the first semi-transparent mirror 10a and transmitted through the second phase difference plate 16b may be reflected as second linearly polarized light and guided toward the viewing window 52.

[0349] Furthermore, the first reflective polarizing plate 18a may reflect light emitted from the second display panel 5b, which has passed through the third phase difference plate 16c, the second semi-transparent mirror 10b, and the fourth phase difference plate 16d, as second linearly polarized light and guide it toward the reflector plate 19. Then, the light reflected by the reflector plate 19 and passed through the fourth phase difference plate 16d may be reflected as second linearly polarized light and guided toward the second semi-transparent mirror 10b. Then, the light reflected by the second semi-transparent mirror 10b and passed through the fourth phase difference plate 16d may be transmitted as first linearly polarized light and guided toward the viewing window 52.

[0350] Therefore, in the display system 111H as well, the first image 9a and the second image 9b can be made visible to the viewer 102 by the first reflective polarizer 18a. Furthermore, even in a configuration where the first display panel 5a is not positioned facing the viewing window 52, ​​the first image 9a can be made visible to the viewer 102. In addition, the first reflective polarizer 18a may reflect light incident from the first display panel 5a side and guide it towards the viewing window 52 side, and transmit light incident from the second display panel 5b side and guide it towards the viewing window 52 side. This makes it easier for the optical system 6 to form an image such that at least a part of the first image 9a and at least a part of the second image 9b overlap.

[0351] In this embodiment, as described above, the reflector 19 may include a first reflector 19a and a second reflector 19b. In this case, the first reflective polarizer 18a may emit from the first display panel 5a and transmit light that has passed through the first phase difference plate 16a, the first semi-transparent mirror 10a, and the second phase difference plate 16b as first linearly polarized light and guide it toward the first reflector 19a. Then, the light that has been reflected by the first reflector 19a and transmitted through the fourth phase difference plate 16d may be transmitted as first linearly polarized light and guided toward the first semi-transparent mirror 10a. Alternatively, the first reflective polarizer 18a may emit from the second display panel 5b and reflect light that has passed through the third phase difference plate 16c, the second semi-transparent mirror 10b, and the fourth phase difference plate 16d as second linearly polarized light and guide it toward the second reflector 19b. The light reflected by the second reflector 19b and transmitted through the fourth phase difference plate 16d may then be reflected as second linearly polarized light and guided towards the second semi-transparent mirror 10b. The display system 111H can achieve the above-described effects even in a configuration comprising the first reflector 19a and the second reflector 19b.

[0352] Furthermore, in the display system 111H, since the second phase difference plate 16b is positioned along the first reflective polarizing plate 18a, the vertical size of the housing 1 can be reduced. Also, since the fourth phase difference plate 16d is positioned along the first reflective polarizing plate 18a, the front-to-back size of the housing 1 can be reduced. Therefore, the housing 1 can be made more compact.

[0353] In this embodiment as well, the focal length of the first semi-transparent mirror 10a may be longer or shorter than the first optical path length. Similarly, the focal length of the second semi-transparent mirror 10b may be longer or shorter than the second optical path length. Furthermore, by appropriately adjusting the focal length, the first optical path length, and the second optical path length, the imaging position and size of the first image 9a and the second image 9b can be changed.

[0354] Furthermore, while the above describes an example in which the display system 111H includes a first reflector 19a and a second reflector 19b as reflectors 19, it is not limited to this. The display system 111H may include a reflector 17 as a reflector 19, as well as a fifth phase difference plate 16e, similar to the display system 111C illustrated in Figure 22. In this case, the fifth phase difference plate 16e in the display system 111H may be located between the reflector 17 and the fourth phase difference plate 16d.

[0355] 〔summary〕 A display system according to Embodiment 1 of the present disclosure comprises a housing having a viewing section, a first display panel for displaying a first display image, a second display panel for displaying a second display image, and an optical system for forming an image of a first image based on the first display image and a second image based on the second display image, wherein when the inside of the housing is viewed from the viewing section, at least a portion of the first image and at least a portion of the second image overlap.

[0356] A display system according to aspect 2 of the present disclosure comprises a housing having a viewing section, a first display panel for displaying a first display image, a second display panel for displaying a second display image, and an optical system for forming a first image based on the first display image, wherein when the inside of the housing is viewed from the viewing section, at least a portion of the first image and at least a portion of the second display image are positioned to overlap.

[0357] The display system according to Embodiment 3 of the present disclosure, in Embodiment 1, comprises a reflecting mirror, a first reflective polarizing plate located between the first display panel and the reflecting mirror and between the second display panel and the viewing section, which transmits first linearly polarized light and reflects second linearly polarized light, a first semi-transparent mirror located between the first display panel and the first reflective polarizing plate, which transmits light incident from the first display panel side and reflects light incident from the first reflective polarizing plate side, a first phase difference plate located between the first display panel and the first semi-transparent mirror, a second phase difference plate located between the first semi-transparent mirror and the first reflective polarizing plate, a second semi-transparent mirror located between the second display panel and the first reflective polarizing plate, which transmits light incident from the second display panel side and reflects light incident from the first reflective polarizing plate side, a third phase difference plate located between the second display panel and the second semi-transparent mirror, and the second semi-transparent mirror and the first reflective polarizing plate. The system comprises a fourth phase difference plate located between the first and second phase difference plates, the reflector reflects light incident from the first reflective polarizer side, the first reflective polarizer emits light from the first display panel, transmits light that has passed through the first phase difference plate, the first semi-transparent mirror and the second phase difference plate as first linearly polarized light and guides it to the reflector side, transmits the light reflected by the reflector as first linearly polarized light and guides it to the first semi-transparent mirror side, reflects it by the first semi-transparent mirror and guides it to the second phase difference plate The transmitted light is reflected as the second linearly polarized light and guided toward the viewing area; the light emitted from the second display panel and transmitted through the third phase difference plate, the second semi-transparent mirror, and the fourth phase difference plate is reflected as the second linearly polarized light and guided toward the reflector side; the light reflected by the reflector is reflected as the second linearly polarized light and guided toward the second semi-transparent mirror side; and the light reflected by the second semi-transparent mirror and transmitted through the fourth phase difference plate is transmitted as the first linearly polarized light and guided toward the viewing area side.

[0358] A display system according to Embodiment 4 of the present disclosure, in Embodiment 1, comprises at least one reflector; a second reflective polarizer positioned between the first display panel and the reflector, and between the second display panel and the viewing section, which transmits first circularly polarized light and reflects second circularly polarized light; a first semi-transparent mirror positioned between the first display panel and the second reflective polarizer, which transmits light incident from the first display panel side and reflects light incident from the second reflective polarizer side; a first phase difference plate positioned between the first display panel and the first semi-transparent mirror; a second semi-transparent mirror positioned between the second display panel and the second reflective polarizer, which transmits light incident from the second display panel side and reflects light incident from the second reflective polarizer side; and a third semi-transparent mirror positioned between the second display panel and the second semi-transparent mirror. The device comprises a phase difference plate and a reflector, the reflector reflects light incident from the second reflective polarizer side, the second reflective polarizer transmits light emitted from the first display panel, which has passed through the first phase difference plate and the first semi-transparent mirror as first circularly polarized light and guides it to the reflector side, transmits the light reflected by the reflector as first circularly polarized light and guides it to the first semi-transparent mirror side, reflects the light reflected by the first semi-transparent mirror as second circularly polarized light and guides it to the viewing section side, the reflector transmits the light emitted from the second display panel, which has passed through the third phase difference plate and the second semi-transparent mirror as second circularly polarized light and guides it to the reflector side, reflects the light reflected by the reflector as second circularly polarized light and guides it to the second semi-transparent mirror side, and transmits the light reflected by the second semi-transparent mirror as first circularly polarized light and guides it to the viewing section side.

[0359] The display system according to aspect 5 of the present disclosure, in aspect 4, wherein the reflector includes a first reflector and a second reflector, and the second reflective polarizing plate transmits light emitted from the first display panel and transmitted through the first phase difference plate and the first semi-transparent mirror as first circularly polarized light and guides it toward the first reflector side, transmits light reflected by the first reflector as first circularly polarized light and guides it toward the first semi-transparent mirror side, reflects light emitted from the second display panel and transmitted through the third phase difference plate and the second semi-transparent mirror as second circularly polarized light and guides it toward the second reflector side, and reflects light reflected by the second reflector as second circularly polarized light and guides it toward the second semi-transparent mirror side.

[0360] The display system according to aspect 6 of the present disclosure, in aspect 1, comprises: a first reflective polarizing plate located between the second display panel and the viewing section, which transmits first linearly polarized light and reflects second linearly polarized light; a first semi-transparent mirror located between the first display panel and the first reflective polarizing plate, which transmits light incident from the first display panel side and reflects light incident from the first reflective polarizing plate side; a second semi-transparent mirror located between the second display panel and the first reflective polarizing plate, which transmits light incident from the second display panel side and reflects light incident from the first reflective polarizing plate side; a third phase difference plate located between the second display panel and the second semi-transparent mirror; and a second semi-transparent mirror located between the second semi-transparent mirror and the first reflective polarizing plate. The first reflective polarizing plate includes a fourth phase difference plate, and the first reflective polarizing plate reflects light emitted from the first display panel and transmitted through the first semi-transparent mirror as second linearly polarized light and guides it toward the second semi-transparent mirror side, reflects the light reflected by the second semi-transparent mirror and transmitted through the fourth phase difference plate as first linearly polarized light and guides it toward the viewing area side, and the first reflective polarizing plate includes a fourth phase difference plate, and the first reflective polarizing plate reflects light emitted from the second display panel and transmitted through the third phase difference plate, the second semi-transparent mirror and the fourth phase difference plate as second linearly polarized light and guides it toward the first semi-transparent mirror side, reflects the light reflected by the first semi-transparent mirror as second linearly polarized light and guides it toward the second semi-transparent mirror side, and the first reflective polarizing plate reflects the light reflected by the second semi-transparent mirror and transmits it through the fourth phase difference plate as first linearly polarized light and guides it toward the viewing area side.

[0361] The display system according to Embodiment 7 of the present disclosure, in Embodiment 6, comprises a third display panel for displaying a third display image, and the first reflective polarizing plate reflects the light emitted from the third display panel as the second linearly polarized light and guides it toward the viewing portion.

[0362] The display system according to aspect 8 of the present disclosure, in aspect 1, comprises a reflecting mirror, a first reflective polarizing plate located between the first display panel and the reflecting mirror and between the second display panel and the viewing section, which transmits first linearly polarized light and reflects second linearly polarized light, a first semi-transparent mirror located between the first display panel and the first reflective polarizing plate, which transmits light incident from the first display panel side and reflects light incident from the first reflective polarizing plate side, and between the first display panel and the first semi-transparent mirror A first phase difference plate located at the top, a second phase difference plate located between the first semi-transparent mirror and the first reflective polarizer, a third reflective polarizer located between the second phase difference plate and the first reflective polarizer, which transmits the second linearly polarized light and reflects the first linearly polarized light, a second semi-transparent mirror located between the second display panel and the first reflective polarizer, which transmits light incident from the second display panel side and reflects light incident from the first reflective polarizer side, and a third phase difference plate located between the second display panel and the second semi-transparent mirror. The system comprises a fourth phase difference plate located between the second semi-transparent mirror and the first reflective polarizer, wherein the mirror reflects light incident from the first reflective polarizer side, and the third reflective polarizer is emitted from the first display panel, reflects light that has passed through the first phase difference plate, the first semi-transparent mirror, and the second phase difference plate as first linearly polarized light and guides it toward the first semi-transparent mirror side, reflects the light that has passed through the second phase difference plate as second linearly polarized light and guides it toward the first reflective polarizer side, and The first reflective polarizing plate reflects the light that has passed through the third reflective polarizing plate as the second linearly polarized light and guides it toward the viewing area. The light emitted from the second display panel and that has passed through the third phase difference plate, the second semi-transparent mirror, and the fourth phase difference plate is reflected as the second linearly polarized light and guided toward the reflector side. The light reflected by the reflector is reflected as the second linearly polarized light and guided toward the second semi-transparent mirror side. The light that has been reflected by the second semi-transparent mirror and passed through the fourth phase difference plate is transmitted as the first linearly polarized light and guided toward the viewing area side.

[0363] A display system according to aspect 9 of the present disclosure, in aspect 1, the optical system comprises at least one reflector, a first reflective polarizer located between the first display panel and the reflector and between the second display panel and the viewing section, which transmits first linearly polarized light and reflects second linearly polarized light, a first semi-transparent mirror located between the first display panel and the second reflective polarizer, which transmits light incident from the first display panel side and reflects light incident from the first reflective polarizer side, and the first display panel A first phase difference plate located between the first semi-transparent mirror and the first semi-transparent mirror; a second phase difference plate located between the first semi-transparent mirror and the first reflective polarizer, along the first reflective polarizer; a second semi-transparent mirror located between the second display panel and the first reflective polarizer, which transmits light incident from the second display panel side and reflects light incident from the first reflective polarizer side; a third phase difference plate located between the second display panel and the second semi-transparent mirror; and between the second semi-transparent mirror and the first reflective polarizer, The system comprises a fourth phase difference plate positioned along the first reflective polarizing plate, the reflector reflects light incident from the first reflective polarizing plate side, the first reflective polarizing plate transmits light emitted from the first display panel, through the first phase difference plate, the first semi-transparent mirror, and the second phase difference plate as first linearly polarized light and guides it to the reflector side, where it is reflected by the reflector, and transmits light that has passed through the fourth phase difference plate as first linearly polarized light and guides it to the first semi-transparent mirror side, where it is reflected by the first semi-transparent mirror, and the second Light transmitted through the phase difference plate is reflected as the second linearly polarized light and guided toward the viewing area. Light emitted from the second display panel, transmitted through the third phase difference plate, the second semi-transparent mirror, and the fourth phase difference plate, is reflected as the second linearly polarized light and guided toward the reflector side. The light is reflected by the reflector, transmitted through the fourth phase difference plate, reflected as the second linearly polarized light and guided toward the second semi-transparent mirror side. The light is reflected by the second semi-transparent mirror, transmitted through the fourth phase difference plate, and guided toward the viewing area side as the first linearly polarized light.

[0364] The display system according to aspect 10 of the present disclosure, in aspect 9, the reflector includes a first reflector and a second reflector, the first reflective polarizing plate emits from the first display panel, transmits light that has passed through the first phase difference plate, the first semi-transparent mirror and the second phase difference plate as first linearly polarized light and guides it toward the first reflector side, reflects it at the first reflector, transmits light that has passed through the fourth phase difference plate as first linearly polarized light and guides it toward the first semi-transparent mirror side, emits from the second display panel, reflects light that has passed through the third phase difference plate, the second semi-transparent mirror and the fourth phase difference plate as second linearly polarized light and guides it toward the second reflector side, reflects it at the second reflector, reflects light that has passed through the fourth phase difference plate as second linearly polarized light and guides it toward the second semi-transparent mirror side.

[0365] The display system according to aspect 11 of the present disclosure, in aspect 5 or 10, wherein the first reflector is a reflective polarizer that transmits second circularly polarized light and reflects first circularly polarized light, and the second reflector is a reflective polarizer that transmits first circularly polarized light and reflects second circularly polarized light.

[0366] The display system according to aspect 12 of the present disclosure, in aspect 1, comprises: a reflecting mirror; a first reflective polarizing plate located between the first display panel and the reflecting mirror and between the second display panel and the viewing section, which transmits first linearly polarized light and reflects second linearly polarized light; a second semi-transparent mirror located between the second display panel and the first reflective polarizing plate, which transmits light incident from the second display panel side and reflects light incident from the first reflective polarizing plate side; a third phase difference plate located between the second display panel and the second semi-transparent mirror; and a fourth phase difference plate located between the second semi-transparent mirror and the first reflective polarizing plate. The device comprises a plate and a reflector, the reflector reflects light incident from the first reflective polarizer side, the first reflective polarizer reflects light emitted from the first display panel as second linearly polarized light and guides it to the viewing section side, the light emitted from the second display panel that has passed through the third phase difference plate, the second semi-transparent mirror and the fourth phase difference plate is reflected as second linearly polarized light and guides it to the reflector side, the light reflected by the reflector is reflected as second linearly polarized light and guides it to the second semi-transparent mirror side, and the light reflected by the second semi-transparent mirror that has passed through the fourth phase difference plate is transmitted as first linearly polarized light and guided to the viewing section side.

[0367] In any of embodiments 3 to 11, the display system according to embodiment 13 of the present disclosure has a focal length of the first semi-transparent mirror, wherein the focal length of the first semi-transparent mirror is the optical path length of the light emitted from the first display panel, and is shorter than the optical path length from the first display panel to the first semi-transparent mirror, where the light emitted from the first display panel passes through the first semi-transparent mirror and re-enters the first semi-transparent mirror.

[0368] In any of embodiments 3 to 11, the display system according to embodiment 14 of the present disclosure has a focal length of the first semi-transparent mirror, wherein the focal length of the first semi-transparent mirror is the optical path length of the light emitted from the first display panel, and is longer than the optical path length from the first display panel until the light emitted from the first display panel passes through the first semi-transparent mirror and re-enters the first semi-transparent mirror.

[0369] In any of embodiments 3 to 12, the display system according to embodiment 15 of the present disclosure has a focal length of the second semi-transparent mirror, wherein the focal length of the second semi-transparent mirror is the optical path length of the light emitted from the second display panel, and is shorter than the optical path length from the second display panel to the second semi-transparent mirror, and then to the second semi-transparent mirror again.

[0370] In any of embodiments 3 to 12, the display system according to embodiment 16 of the present disclosure has a focal length of the second semi-transparent mirror, wherein the focal length of the second semi-transparent mirror is the optical path length of the light emitted from the second display panel, and is longer than the optical path length from the second display panel until the light emitted from the second display panel passes through the second semi-transparent mirror and re-enters the second semi-transparent mirror.

[0371] A display system according to aspect 17 of the present disclosure, in aspect 1, comprises: a first display device having a first display panel and a first optical system which is part of the optical system and which can form an image of a first image at a position different from the first display panel by emitting a first polarization based on the first display image; a second display device having a second display panel and a second optical system which is part of the optical system and which can form an image of a second image at a position different from the second display panel by emitting a second polarization based on the second display image; and a reflective polarizing plate which is part of the optical system and which reflects the first polarization emitted from the first display device and guides it to the viewing section, wherein the first polarization reflected by the reflective polarizing plate and the second polarization emitted from the second display device are emitted from the viewing section.

[0372] A display system according to aspect 18 of the present disclosure, in aspect 2, comprises: a first display device having a first display panel for displaying the first display image; a first optical system which is part of the optical system and is capable of imaging the first image at a position different from the first display panel by emitting a first polarization based on the first display image; a second display device having a second display panel and emitting a second polarization based on the second display image; and a reflective polarizing plate which is part of the optical system and is capable of reflecting the first polarization emitted from the first display device and guiding it to the viewing section, wherein the first polarization reflected by the reflective polarizing plate and the second polarization emitted from the second display device are emitted from the viewing section.

[0373] A display system according to aspect 19 of the present disclosure, in aspect 1, comprises: a first display device having a first display panel for displaying the first display image and emitting a first polarization based on the first display image; a second display panel; a second optical system which is part of the optical system and is capable of forming a second image at a position different from the second display panel by emitting a second polarization based on the second display image; and a reflective polarizing plate which is part of the optical system and reflects the first polarization emitted from the first display device and guides it to the viewing section, wherein the first polarization reflected by the reflective polarizing plate and the second polarization emitted from the second display device are emitted from the viewing section.

[0374] In the display system according to aspect 20 of the present disclosure, in any of aspects 17 to 19, the reflective polarizing plate transmits the second polarized light emitted from the second display device.

[0375] In the display system according to aspect 21 of this disclosure, in any of aspects 17 to 19, the position of the reflective polarizer is different from the position on the optical path of the second polarized light emitted from the second display device.

[0376] In the display system according to aspect 22 of this disclosure, in any of aspects 17 to 21, the normal direction of the first display panel and the normal direction of the second display panel are orthogonal.

[0377] In the display system according to aspect 23 of the present disclosure, in aspect 22, the angle between the optical path of the second polarization emitted from the second display device and the reflective polarizer is 45°, and the angle between the optical path of the first polarization emitted from the first display device and the reflective polarizer on the side of the first display device from the reflective polarizer is 45°.

[0378] In the display system according to aspect 24 of this disclosure, in aspect 22, the angle between the optical path of the second polarization emitted from the second display device and the reflective polarizer is different from the angle between the optical path of the first polarization emitted from the first display device and the reflective polarizer on the side of the first display device that is closer to the reflective polarizer.

[0379] In the display system according to aspect 25 of the present disclosure, in aspect 20, the reflection position of the first polarization emitted from the first display device on the reflective polarizing plate is the first portion of the reflective polarizing plate, and the transmission position of the second polarization emitted from the second display device on the reflective polarizing plate is the first portion of the reflective polarizing plate.

[0380] In the display system according to aspect 26 of the present disclosure, in aspect 20, the reflection position of the first polarization emitted from the first display device on the reflective polarizing plate is a first portion of the reflective polarizing plate, and the transmission position of the second polarization emitted from the second display device on the reflective polarizing plate is a second portion of the reflective polarizing plate that is different from the first portion.

[0381] The display system according to aspect 27 of the present disclosure, in aspect 17 or 18, wherein the first optical system has a semi-transparent mirror, and the upright direction of the first display panel and the upright direction of the semi-transparent mirror are different.

[0382] In the display system according to aspect 28 of the present disclosure, in aspect 17 or 19, the second optical system has a semi-transparent mirror, and the upright direction of the second display panel and the upright direction of the semi-transparent mirror are different.

[0383] The display system according to aspect 29 of this disclosure is characterized in that, in any of aspects 17 to 28, one of the first polarization and the second polarization is P-polarized and the other is S-polarized.

[0384] The mobile device according to aspect 30 of this disclosure comprises a display system as described in aspects 1 to 29.

[0385] A display system according to aspect 31 of the present disclosure comprises a display system from any of aspects 1 to 29 and a camera capable of communicating with the display system, wherein at least one of the first display panel and the second display panel displays an image captured by the camera.

[0386] A display panel housing device according to embodiment 32 of the present disclosure is a non-user-mounted display panel housing device comprising: a housing having a viewing section; a first display panel installation section capable of installing a first display panel for displaying a first display image; and a second display panel installation section capable of installing a second display panel for displaying a second display image; and an optical system located inside the housing and forming an image of a first image based on the first display image and a second image based on the second display image, wherein when the inside of the housing is viewed from the viewing section, at least a portion of the first image and at least a portion of the second image overlap.

[0387] A display panel housing device according to embodiment 33 of the present disclosure is a non-user-mounted display panel housing device comprising: a housing having a viewing section; a first display panel installation section capable of installing a first display panel for displaying a first display image; and a second display panel installation section capable of installing a second display panel for displaying a second display image; and an optical system located inside the housing and forming a first image based on the first display image, wherein when the inside of the housing is viewed from the viewing section, at least a portion of the first image and at least a portion of the second display image overlap.

[0388] A display system according to embodiment 34 of the present disclosure is installable in a first housing having a first viewing unit and comprises a second housing having a second viewing unit, a first display panel located inside the second housing and displaying a first display image, a second display panel located inside the second housing and displaying a second display image, and an optical system located inside the second housing that forms an image of a first image based on the first display image and a second image based on the second display image, wherein when the inside of the second housing is viewed from the second viewing unit, at least a portion of the first image and at least a portion of the second image overlap.

[0389] A display system according to embodiment 35 of the present disclosure is installable in a first housing having a first viewing unit and comprises a second housing having a second viewing unit, a first display panel located inside the second housing and displaying a first display image, a second display panel located inside the second housing and displaying a second display image, and an optical system located inside the second housing and forming a first image based on the first display image, wherein when the inside of the second housing is viewed from the second viewing unit, at least a portion of the first image and at least a portion of the second display image overlap.

[0390] A display system according to aspect 36 of the present disclosure comprises a first housing having a first viewing section, a second housing installed inside the first housing and having a second viewing section, a first display panel located inside the second housing and displaying a first display image, a second display panel located inside the second housing and displaying a second display image, and an optical system located inside the second housing that forms an image of a first image based on the first display image and a second image based on the second display image, wherein when the inside of the second housing is viewed from the second viewing section through the first viewing section, at least a portion of the first image and at least a portion of the second image overlap.

[0391] A display system according to aspect 37 of the present disclosure comprises a first housing having a first viewing section, a second housing installed inside the first housing and having a second viewing section, a first display panel located inside the second housing and displaying a first display image, a second display panel located inside the second housing and displaying a second display image, and an optical system located inside the second housing and forming a first image based on the first display image, wherein when the inside of the second housing is viewed from the second viewing section through the first viewing section, at least a portion of the first image and at least a portion of the second display image overlap.

[0392] A display device unit according to embodiment A of the present disclosure comprises: a first display device having a housing having an opening; a first display panel for displaying a first display image; and a first optical system capable of forming a first image based on the first display image at a position different from the first display panel by emitting a first polarization based on the first display image; a second display device having a second display panel for displaying a second display image; and a second optical system capable of forming a second image based on the second display image at a position different from the second display panel by emitting a second polarization based on the second display image; and a reflective polarizing plate that reflects the first polarization emitted from the first display device and guides it to the opening, wherein the first polarization reflected by the reflective polarizing plate and the second polarization emitted from the second display device are emitted from the opening.

[0393] A display device unit according to embodiment B of the present disclosure comprises a first display device having a housing having an opening, a first display panel for displaying a first display image, and a first optical system capable of forming a first image based on the first display image at a position different from the first display panel by emitting a first polarization based on the first display image; a second display device having a second display panel for displaying a second display image and emitting a second polarization based on the second display image; and a reflective polarizing plate that reflects the first polarization emitted from the first display device and guides it to the opening, wherein the first polarization reflected by the reflective polarizing plate and the second polarization emitted from the second display device are emitted from the opening.

[0394] A display device unit according to embodiment C of the present disclosure comprises a housing having an opening; a first display device having a first display panel for displaying a first display image and emitting a first polarization based on the first display image; a second display device having a second display panel for displaying a second display image; a second optical system that emits a second polarization based on the second display image, thereby enabling the formation of a second image based on the second display image at a position different from the second display panel; and a reflective polarizing plate that reflects the first polarization emitted from the first display device and guides it to the opening, and the first polarization reflected by the reflective polarizing plate and the second polarization emitted from the second display device are emitted from the opening.

[0395] In the display device unit according to embodiment D of the present disclosure, in any of embodiments A to C, the reflective polarizing plate transmits the second polarized light emitted from the second display device.

[0396] In the display device unit according to embodiment E of the present disclosure, in any of embodiments A to C, the position of the reflective polarizer is different from the position on the optical path of the second polarized light emitted from the second display device.

[0397] In the display unit according to embodiment F of the present disclosure, in any of embodiments A to E, the normal direction of the first display panel and the normal direction of the second display panel are orthogonal.

[0398] In the display device unit according to aspect G of the present disclosure, in aspect F, the angle between the optical path of the second polarized light emitted from the second display device and the reflective polarizer is 45°, and the angle between the optical path of the first polarized light emitted from the first display device and the reflective polarizer on the side of the first display device from the reflective polarizer is 45°.

[0399] In the display device unit according to embodiment H of the present disclosure, in embodiment F, the angle between the optical path of the second polarization emitted from the second display device and the reflective polarizer is different from the angle between the optical path of the first polarization emitted from the first display device and the reflective polarizer on the side of the first display device that is closer to the reflective polarizer.

[0400] In the display device unit according to Embodiment I of this disclosure, in Embodiment D, the reflection position of the first polarization emitted from the first display device on the reflective polarizing plate is the first portion of the reflective polarizing plate, and the transmission position of the second polarization emitted from the second display device on the reflective polarizing plate is the first portion of the reflective polarizing plate.

[0401] In the display device unit according to embodiment J of the present disclosure, in embodiment D, the reflection position of the first polarization emitted from the first display device on the reflective polarizing plate is a first portion of the reflective polarizing plate, and the transmission position of the second polarization emitted from the second display device on the reflective polarizing plate is a second portion of the reflective polarizing plate that is different from the first portion.

[0402] In the display device unit according to embodiment K of the present disclosure, in embodiment A or B, the first optical system has a semi-transparent mirror, and the upright direction of the first display panel and the upright direction of the semi-transparent mirror are different.

[0403] In the display device unit according to embodiment L of the present disclosure, in embodiment A or C, the second optical system has a semi-transparent mirror, and the upright direction of the second display panel and the upright direction of the semi-transparent mirror are different.

[0404] In any of embodiments A to L, the display device unit according to embodiment M of this disclosure is characterized in that one of the first polarization and the second polarization is P polarization and the other is S polarization.

[0405] A vehicle relating to aspect N of this disclosure is equipped with the display unit in any of aspects A to M.

[0406] The inventions described in this disclosure have been explained above based on the drawings and embodiments. However, the inventions described in this disclosure are not limited to the embodiments described above. That is, the inventions described in this disclosure can be modified in various ways within the scope shown in this disclosure, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the inventions described in this disclosure. In other words, it should be noted that it is easy for those skilled in the art to make various modifications or alterations based on this disclosure. Furthermore, it should be noted that these modifications or alterations are included in the scope of this disclosure. [Explanation of symbols]

[0407] 1 cabinet 2a 1st display device 2b 2nd display device 3 Reflective polarizing plate (optical system) 4. Opening (visibility area) 5 Display Panel 5a First display panel 5b Second display panel 5c Third display panel 6 Optical system 6a 1st optical system (optical system) 6b Second optical system (optical system) 7 Displayed Images 7a First display image 7b Second display image 8 Polarization 8a First Polarization 8b Second Polarization 9a 1st image 9b 2nd image 10 Semi-transparent mirror 10a 1st semi-transparent mirror 10b Second semi-transparent mirror 11a Optical path of the first polarization emitted from the first display device 11b Optical path of the second polarization emitted from the second display device 12 Part 1 13 Part 2 15 Touch panel 16a 1st retardation plate 16b 2nd phase difference plate 16c 3rd retardation plate 16d 4th retardation plate 17 Reflector 18a First Reflecting Polarizer 18b 2nd reflective polarizer 19 Reflector 19a 1st reflector 19b 2nd reflector 50a Installation section for the first display panel 50b Installation section for the second display panel 52. Viewing window (viewing section) 100 Display Systems 100A Display System 100B Display System 101 Display Unit (Display System) 111A~111H Display System 115 Second cabinet 116 Second Visibility Section 120 Display panel housing device 130 Display Systems 131 First cabinet 132 First Visibility Section θa is the angle between the optical path of the first polarized light emitted from the first display device and the reflective polarizer, on the side of the first display device that is closer to the reflective polarizer. θb: The angle between the optical path of the second polarized light emitted from the second display device and the reflecting polarizer.

Claims

1. A housing having a viewing section, A first display panel that displays the first display image, A second display panel that displays a second display image, The system comprises an optical system that forms an image of a first image based on the first display image and a second image based on the second display image, When the inside of the housing is viewed from the viewing section, the first image and the second image are positioned to overlap, The optical system described above is A reflector, A first reflective polarizing plate is located between the first display panel and the reflector, and between the second display panel and the viewing section, and transmits first linearly polarized light and reflects second linearly polarized light. A first semi-transparent mirror is positioned between the first display panel and the first reflective polarizing plate, and transmits light incident from the first display panel side and reflects light incident from the first reflective polarizing plate side. A first phase difference plate is located between the first display panel and the first semitransparent mirror, A second phase difference plate is located between the first semi-transparent mirror and the first reflective polarizing plate, A second semi-transparent mirror is positioned between the second display panel and the first reflective polarizer, and transmits light incident from the second display panel side and reflects light incident from the first reflective polarizer side. A third phase difference plate is located between the second display panel and the second semi-transparent mirror, The system comprises a fourth phase difference plate located between the second semi-transparent mirror and the first reflective polarizing plate, The aforementioned reflector reflects light incident from the side of the first reflecting polarizer, The first reflective polarizing plate is Light emitted from the first display panel and transmitted through the first phase difference plate, the first semi-transparent mirror, and the second phase difference plate is transmitted as first linearly polarized light and guided to the reflector side, the light reflected by the reflector is transmitted as first linearly polarized light and guided to the first semi-transparent mirror side, the light reflected by the first semi-transparent mirror and transmitted through the second phase difference plate is reflected as second linearly polarized light and guided to the viewing section side, A display system comprising: light emitted from the second display panel, transmitted through the third phase difference plate, the second semi-transparent mirror, and the fourth phase difference plate, reflected as second linearly polarized light and guided to the reflector side; light reflected by the reflector, reflected as second linearly polarized light and guided to the second semi-transparent mirror side; and light reflected by the second semi-transparent mirror, transmitted through the fourth phase difference plate, transmitted as first linearly polarized light and guided to the viewing section side.

2. A housing having a viewing section, A first display panel that displays the first display image, A second display panel that displays a second display image, The system comprises an optical system that forms an image of a first image based on the first display image and a second image based on the second display image, When the inside of the housing is viewed from the viewing section, the first image and the second image are positioned to overlap, The optical system described above is At least one reflector, A second reflective polarizing plate is located between the first display panel and the reflector, and between the second display panel and the viewing section, and transmits first circularly polarized light and reflects second circularly polarized light. A first semi-transparent mirror is positioned between the first display panel and the second reflective polarizing plate, and transmits light incident from the first display panel side and reflects light incident from the second reflective polarizing plate side. A first phase difference plate is located between the first display panel and the first semitransparent mirror, A second semi-transparent mirror is positioned between the second display panel and the second reflective polarizer, and transmits light incident from the second display panel side and reflects light incident from the second reflective polarizer side. The system comprises a third phase difference plate located between the second display panel and the second semi-transparent mirror, The reflector reflects light incident from the second polarizing plate side, The second reflective polarizing plate is Light emitted from the first display panel and transmitted through the first phase difference plate and the first semi-transparent mirror is transmitted as first circularly polarized light and guided to the reflector side, the light reflected by the reflector is transmitted as first circularly polarized light and guided to the first semi-transparent mirror side, and the light reflected by the first semi-transparent mirror is reflected as second circularly polarized light and guided to the viewing section side. A display system comprising: light emitted from the second display panel, transmitted through the third phase difference plate and the second semi-transparent mirror, reflected as second circularly polarized light and guided to the reflector side; light reflected by the reflector, reflected as second circularly polarized light and guided to the second semi-transparent mirror side; and light reflected by the second semi-transparent mirror, transmitted as first circularly polarized light and guided to the viewing section side.

3. The reflector includes a first reflector and a second reflector, The second reflective polarizing plate is Light emitted from the first display panel and transmitted through the first phase difference plate and the first semi-transparent mirror is transmitted as first circularly polarized light and guided to the first reflector side, and the light reflected by the first reflector is transmitted as first circularly polarized light and guided to the first semi-transparent mirror side, The display system according to claim 2, wherein light emitted from the second display panel and transmitted through the third phase difference plate and the second semitransparent mirror is reflected as second circularly polarized light and guided to the second reflector side, and the light reflected by the second reflector is reflected as second circularly polarized light and guided to the second semitransparent mirror side.

4. A housing having a viewing section, A first display panel that displays the first display image, A second display panel that displays a second display image, The system comprises an optical system that forms an image of a first image based on the first display image and a second image based on the second display image, When the inside of the housing is viewed from the viewing section, the first image and the second image are positioned to overlap, The optical system described above is A first reflective polarizing plate is located between the second display panel and the viewing section, and transmits first linearly polarized light and reflects second linearly polarized light. A first semi-transparent mirror is positioned between the first display panel and the first reflective polarizing plate, and transmits light incident from the first display panel side and reflects light incident from the first reflective polarizing plate side. A second semi-transparent mirror is positioned between the second display panel and the first reflective polarizer, and transmits light incident from the second display panel side and reflects light incident from the first reflective polarizer side. A third phase difference plate is located between the second display panel and the second semi-transparent mirror, The system comprises a fourth phase difference plate located between the second semi-transparent mirror and the first reflective polarizing plate, The first reflective polarizing plate is Light emitted from the first display panel and transmitted through the first semi-transparent mirror is reflected as the second linearly polarized light and guided towards the second semi-transparent mirror, and the light reflected by the second semi-transparent mirror and transmitted through the fourth phase difference plate is transmitted as the first linearly polarized light and guided towards the viewing section. A display system comprising: light emitted from the second display panel, transmitted through the third phase difference plate, the second semi-transparent mirror, and the fourth phase difference plate, reflected as second linearly polarized light and guided to the first semi-transparent mirror side; light reflected by the first semi-transparent mirror, reflected as second linearly polarized light and guided to the second semi-transparent mirror side; and light reflected by the second semi-transparent mirror, transmitted through the fourth phase difference plate, transmitted as first linearly polarized light and guided to the viewing area side.

5. It is equipped with a third display panel that displays a third display image, The display system according to claim 4, wherein the first reflective polarizing plate reflects the light emitted from the third display panel as a second linearly polarized light and guides it toward the viewing area.

6. A housing having a viewing section, A first display panel that displays the first display image, A second display panel that displays a second display image, The system comprises an optical system that forms an image of a first image based on the first display image and a second image based on the second display image, When the inside of the housing is viewed from the viewing section, the first image and the second image are positioned to overlap, The optical system described above is A reflector, A first reflective polarizing plate is located between the first display panel and the reflector, and between the second display panel and the viewing section, and transmits first linearly polarized light and reflects second linearly polarized light. A first semi-transparent mirror is positioned between the first display panel and the first reflective polarizing plate, and transmits light incident from the first display panel side and reflects light incident from the first reflective polarizing plate side. A first phase difference plate is located between the first display panel and the first semitransparent mirror, A second phase difference plate is located between the first semi-transparent mirror and the first reflective polarizing plate, A third reflective polarizing plate is positioned between the second phase difference plate and the first reflective polarizing plate, and transmits the second linearly polarized light and reflects the first linearly polarized light. A second semi-transparent mirror is positioned between the second display panel and the first reflective polarizer, and transmits light incident from the second display panel side and reflects light incident from the first reflective polarizer side. A third phase difference plate is located between the second display panel and the second semi-transparent mirror, The system comprises a fourth phase difference plate located between the second semi-transparent mirror and the first reflective polarizing plate, The aforementioned reflector reflects light incident from the side of the first reflecting polarizer, The third reflective polarizing plate emits light from the first display panel, and reflects the light that has passed through the first phase difference plate, the first semi-transparent mirror, and the second phase difference plate as first linearly polarized light, directing it towards the first semi-transparent mirror, and the light that has been reflected by the first semi-transparent mirror and passed through the second phase difference plate is transmitted as second linearly polarized light, directing it towards the first reflective polarizing plate. The first reflective polarizing plate is The light transmitted through the third reflective polarizing plate is reflected as the second linearly polarized light and guided towards the viewing area. A display system comprising: light emitted from the second display panel, transmitted through the third phase difference plate, the second semi-transparent mirror, and the fourth phase difference plate, reflected as second linearly polarized light and guided to the reflector side; light reflected by the reflector, reflected as second linearly polarized light and guided to the second semi-transparent mirror side; and light reflected by the second semi-transparent mirror, transmitted through the fourth phase difference plate, transmitted as first linearly polarized light and guided to the viewing section side.

7. A housing having a viewing section, A first display panel that displays the first display image, A second display panel that displays a second display image, The system comprises an optical system that forms an image of a first image based on the first display image and a second image based on the second display image, When the inside of the housing is viewed from the viewing section, the first image and the second image are positioned to overlap, The optical system described above is At least one reflector, A first reflective polarizing plate is located between the first display panel and the reflector, and between the second display panel and the viewing section, and transmits first linearly polarized light and reflects second linearly polarized light. A first semi-transparent mirror is positioned between the first display panel and the first reflective polarizing plate, and transmits light incident from the first display panel side and reflects light incident from the first reflective polarizing plate side. A first phase difference plate is located between the first display panel and the first semitransparent mirror, Between the first semi-transparent mirror and the first reflective polarizing plate, a second phase difference plate is positioned along the first reflective polarizing plate, A second semi-transparent mirror is positioned between the second display panel and the first reflective polarizer, and transmits light incident from the second display panel side and reflects light incident from the first reflective polarizer side. A third phase difference plate is located between the second display panel and the second semi-transparent mirror, The system comprises a fourth phase difference plate positioned along the first reflective polarizer between the second semi-transparent mirror and the first reflective polarizer, The reflector reflects light incident from the first reflective polarizer side, The first reflective polarizing plate is Light emitted from the first display panel, transmitted through the first phase difference plate, the first semi-transparent mirror, and the second phase difference plate, is transmitted as first linearly polarized light and guided to the reflector side, reflected by the reflector, transmitted through the fourth phase difference plate, is transmitted as first linearly polarized light and guided to the first semi-transparent mirror side, reflected by the first semi-transparent mirror, transmitted through the second phase difference plate, is reflected as second linearly polarized light and guided to the viewing section side. A display system comprising: light emitted from the second display panel, transmitted through the third phase difference plate, the second semi-transparent mirror, and the fourth phase difference plate, reflected as second linearly polarized light and guided toward the reflector side; light reflected by the reflector and transmitted through the fourth phase difference plate, reflected as second linearly polarized light and guided toward the second semi-transparent mirror side; light reflected by the second semi-transparent mirror and transmitted through the fourth phase difference plate, transmitted as first linearly polarized light and guided toward the viewing section side.

8. The reflector includes a first reflector and a second reflector, The first reflective polarizing plate is Light emitted from the first display panel, transmitted through the first phase difference plate, the first semi-transparent mirror, and the second phase difference plate, is transmitted as first linearly polarized light and guided to the first reflector side, reflected by the first reflector, transmitted through the fourth phase difference plate, is transmitted as first linearly polarized light and guided to the first semi-transparent mirror side, The display system according to claim 7, wherein light emitted from the second display panel and transmitted through the third phase difference plate, the second semi-transparent mirror, and the fourth phase difference plate is reflected as second linearly polarized light and guided toward the second reflector side, and light reflected by the second reflector and transmitted through the fourth phase difference plate is reflected as second linearly polarized light and guided toward the second semi-transparent mirror side.

9. The first reflector is a reflective polarizer that transmits second circularly polarized light and reflects first circularly polarized light. The display system according to claim 3, wherein the second reflector is a reflective polarizer that transmits first circularly polarized light and reflects second circularly polarized light.

10. A housing having a viewing section, A first display panel that displays the first display image, A second display panel that displays a second display image, The system comprises an optical system that forms an image of a first image based on the first display image and a second image based on the second display image, When the inside of the housing is viewed from the viewing section, the first image and the second image are positioned to overlap, The optical system described above is A reflector, A first reflective polarizing plate is located between the first display panel and the reflector, and between the second display panel and the viewing section, and transmits first linearly polarized light and reflects second linearly polarized light. A second semi-transparent mirror is positioned between the second display panel and the first reflective polarizer, and transmits light incident from the second display panel side and reflects light incident from the first reflective polarizer side. A third phase difference plate is located between the second display panel and the second semi-transparent mirror, The system comprises a fourth phase difference plate located between the second semi-transparent mirror and the first reflective polarizing plate, The aforementioned reflector reflects light incident from the side of the first reflecting polarizer, The first reflective polarizing plate is The light emitted from the first display panel is reflected as the second linearly polarized light and guided towards the viewing section. A display system comprising: light emitted from the second display panel, transmitted through the third phase difference plate, the second semi-transparent mirror, and the fourth phase difference plate, reflected as second linearly polarized light and guided to the reflector side; light reflected by the reflector, reflected as second linearly polarized light and guided to the second semi-transparent mirror side; and light reflected by the second semi-transparent mirror, transmitted through the fourth phase difference plate, transmitted as first linearly polarized light and guided to the viewing section side.

11. The display system according to claim 1, wherein the focal length of the first semi-transparent mirror is the optical path length of the light emitted from the first display panel, and is shorter than the optical path length from the first display panel until the light emitted from the first display panel passes through the first semi-transparent mirror and re-enters the first semi-transparent mirror.

12. The display system according to claim 1, wherein the focal length of the first semi-transparent mirror is the optical path length of the light emitted from the first display panel, and is longer than the optical path length from the first display panel until the light emitted from the first display panel passes through the first semi-transparent mirror and re-enters the first semi-transparent mirror.

13. The display system according to claim 1, wherein the focal length of the second semi-transparent mirror is the optical path length of the light emitted from the second display panel, and is shorter than the optical path length from the second display panel until the light emitted from the second display panel passes through the second semi-transparent mirror and re-enters the second semi-transparent mirror.

14. The display system according to claim 1, wherein the focal length of the second semi-transparent mirror is the optical path length of the light emitted from the second display panel, and is longer than the optical path length from the second display panel until the light emitted from the second display panel passes through the second semi-transparent mirror and re-enters the second semi-transparent mirror.

15. A housing having a viewing section, A first display panel that displays the first display image, A second display panel that displays a second display image, The system comprises an optical system that forms an image of a first image based on the first display image and a second image based on the second display image, When the inside of the housing is viewed from the viewing section, the first image and the second image are positioned to overlap, A first display device comprising: a first display panel; a first optical system which is part of the optical system, and which emits a first polarization based on the first display image, thereby enabling the first image to be imaged at a position different from the first display panel; A second display device comprising: a second display panel; a second optical system which is part of the optical system and which emits a second polarization based on the second display image, thereby enabling the second image to be imaged at a position different from the second display panel; A reflective polarizing plate which is part of the optical system, comprising a reflective polarizing plate that reflects the first polarized light emitted from the first display device and guides it to the viewing section, The first polarized light reflected by the reflective polarizing plate and the second polarized light emitted from the second display device are emitted from the viewing unit. A display system in which the position of the reflective polarizing plate is different from the position on the optical path of the second polarized light emitted from the second display device.

16. A housing having a viewing section, A first display panel that displays the first display image, A second display panel that displays a second display image, The system comprises an optical system for forming a first image based on the first display image, When the inside of the housing is viewed from the viewing section, the first image and at least a portion of the second display image are positioned to overlap. A first display device comprising: a first display panel for displaying the first display image; and a first optical system which is part of the optical system, and which emits a first polarization based on the first display image, thereby enabling the first image to be imaged at a position different from the first display panel; A second display device having the second display panel and emitting a second polarization based on the second display image, A reflective polarizing plate which is part of the optical system, comprising a reflective polarizing plate that reflects the first polarized light emitted from the first display device and guides it to the viewing section, The first polarized light reflected by the reflective polarizing plate and the second polarized light emitted from the second display device are emitted from the viewing unit. A display system in which the position of the reflective polarizing plate is different from the position on the optical path of the second polarized light emitted from the second display device.

17. A housing having a viewing section, A first display panel that displays the first display image, A second display panel that displays a second display image, The system comprises an optical system that forms an image of a first image based on the first display image and a second image based on the second display image, When the inside of the housing is viewed from the viewing section, the first image and the second image are positioned to overlap, A first display device having a first display panel for displaying the first display image and emitting a first polarization based on the first display image, A second display device comprising: a second display panel; a second optical system which is part of the optical system and which emits a second polarization based on the second display image, thereby enabling the second image to be imaged at a position different from the second display panel; A reflective polarizing plate which is part of the optical system, comprising a reflective polarizing plate that reflects the first polarized light emitted from the first display device and guides it to the viewing section, The first polarized light reflected by the reflective polarizing plate and the second polarized light emitted from the second display device are emitted from the viewing unit. A display system in which the position of the reflective polarizing plate is different from the position on the optical path of the second polarized light emitted from the second display device.

18. The display system according to claim 17, wherein the normal direction of the first display panel and the normal direction of the second display panel are orthogonal.

19. The display system according to claim 18, wherein the angle between the optical path of the second polarization emitted from the second display device and the reflective polarizer is 45°, and the angle between the optical path of the first polarization emitted from the first display device and the reflective polarizer on the side of the first display device that is closer to the reflective polarizer is 45°.

20. The display system according to claim 18, wherein the angle between the optical path of the second polarized light emitted from the second display device and the reflective polarizer is different from the angle between the optical path of the first polarized light emitted from the first display device and the reflective polarizer on the side of the first display device that is closer to the reflective polarizer.

21. A housing having a viewing section, A first display panel that displays the first display image, A second display panel that displays a second display image, The system comprises an optical system that forms an image of a first image based on the first display image and a second image based on the second display image, When the inside of the housing is viewed from the viewing section, the first image and the second image are positioned to overlap, A first display device comprising: a first display panel; a first optical system which is part of the optical system, and which emits a first polarization based on the first display image, thereby enabling the first image to be imaged at a position different from the first display panel; A second display device comprising: a second display panel; a second optical system which is part of the optical system and which emits a second polarization based on the second display image, thereby enabling the second image to be imaged at a position different from the second display panel; A reflective polarizing plate which is part of the optical system, comprising a reflective polarizing plate that reflects the first polarized light emitted from the first display device and guides it to the viewing section, The first polarized light reflected by the reflective polarizing plate and the second polarized light emitted from the second display device are emitted from the viewing unit. The first optical system has a semi-transparent mirror, A display system in which the upright direction of the first display panel and the upright direction of the semi-transparent mirror are different.

22. A housing having a viewing section, A first display panel that displays the first display image, A second display panel that displays a second display image, The system comprises an optical system for forming a first image based on the first display image, When the inside of the housing is viewed from the viewing section, the first image and at least a portion of the second display image are positioned to overlap. A first display device comprising: a first display panel for displaying the first display image; and a first optical system which is part of the optical system, and which emits a first polarization based on the first display image, thereby enabling the first image to be imaged at a position different from the first display panel; A second display device having the second display panel and emitting a second polarization based on the second display image, A reflective polarizing plate which is part of the optical system, comprising a reflective polarizing plate that reflects the first polarized light emitted from the first display device and guides it to the viewing section, The first polarized light reflected by the reflective polarizing plate and the second polarized light emitted from the second display device are emitted from the viewing unit. The first optical system has a semi-transparent mirror, A display system in which the upright direction of the first display panel and the upright direction of the semi-transparent mirror are different.

23. A housing having a viewing section, A first display panel that displays the first display image, A second display panel that displays a second display image, The system comprises an optical system that forms an image of a first image based on the first display image and a second image based on the second display image, When the inside of the housing is viewed from the viewing section, the first image and the second image are positioned to overlap, A first display device comprising: a first display panel; a first optical system which is part of the optical system, and which emits a first polarization based on the first display image, thereby enabling the first image to be imaged at a position different from the first display panel; A second display device comprising: a second display panel; a second optical system which is part of the optical system and which emits a second polarization based on the second display image, thereby enabling the second image to be imaged at a position different from the second display panel; A reflective polarizing plate which is part of the optical system, comprising a reflective polarizing plate that reflects the first polarized light emitted from the first display device and guides it to the viewing section, The first polarized light reflected by the reflective polarizing plate and the second polarized light emitted from the second display device are emitted from the viewing unit. The second optical system described above has a semi-transmitting mirror, A display system in which the upright direction of the second display panel and the upright direction of the semi-transparent mirror are different.

24. A housing having a viewing section, A first display panel that displays the first display image, A second display panel that displays a second display image, The system comprises an optical system that forms an image of a first image based on the first display image and a second image based on the second display image, When the inside of the housing is viewed from the viewing section, the first image and the second image are positioned to overlap, A first display device having a first display panel for displaying the first display image and emitting a first polarization based on the first display image, A second display device comprising: a second display panel; a second optical system which is part of the optical system and which emits a second polarization based on the second display image, thereby enabling the second image to be imaged at a position different from the second display panel; A reflective polarizing plate which is part of the optical system, comprising a reflective polarizing plate that reflects the first polarized light emitted from the first display device and guides it to the viewing section, The first polarized light reflected by the reflective polarizing plate and the second polarized light emitted from the second display device are emitted from the viewing unit. The second optical system described above has a semi-transmitting mirror, A display system in which the upright direction of the second display panel and the upright direction of the semi-transparent mirror are different.

25. The display system according to claim 15, wherein one of the first polarization and the second polarization is P-polarized and the other is S-polarized.

26. A mobile body comprising the display system described in claim 1.

27. The display system described in claim 1, The system comprises a camera capable of communicating with the aforementioned display system, A display system in which at least one of the first display panel and the second display panel displays an image captured by the camera.

28. A housing having a viewing section, a first display panel mounting section on which a first display panel for displaying a first display image can be installed, and a second display panel mounting section on which a second display panel for displaying a second display image can be installed, The housing is located within the housing and comprises an optical system that forms an image of a first image based on the first display image and a second image based on the second display image, When the inside of the housing is viewed from the viewing section, the first image and the second image are positioned to overlap, The optical system described above is A reflector, A first reflective polarizing plate is located between the first display panel and the reflector, and between the second display panel and the viewing section, and transmits first linearly polarized light and reflects second linearly polarized light. A first semi-transparent mirror is positioned between the first display panel and the first reflective polarizing plate, and transmits light incident from the first display panel side and reflects light incident from the first reflective polarizing plate side. A first phase difference plate is located between the first display panel and the first semitransparent mirror, A second phase difference plate is located between the first semi-transparent mirror and the first reflective polarizing plate, A second semi-transparent mirror is positioned between the second display panel and the first reflective polarizer, and transmits light incident from the second display panel side and reflects light incident from the first reflective polarizer side. A third phase difference plate is located between the second display panel and the second semi-transparent mirror, The system comprises a fourth phase difference plate located between the second semi-transparent mirror and the first reflective polarizing plate, The aforementioned reflector reflects light incident from the side of the first reflecting polarizer, The first reflective polarizing plate is Light emitted from the first display panel and transmitted through the first phase difference plate, the first semi-transparent mirror, and the second phase difference plate is transmitted as first linearly polarized light and guided to the reflector side, the light reflected by the reflector is transmitted as first linearly polarized light and guided to the first semi-transparent mirror side, the light reflected by the first semi-transparent mirror and transmitted through the second phase difference plate is reflected as second linearly polarized light and guided to the viewing section side, A non-user-mounted display panel housing device that emits light from the second display panel, passes through the third phase difference plate, the second semi-transparent mirror, and the fourth phase difference plate, reflects the light as second linearly polarized light and guides it to the reflector side, reflects the light reflected by the reflector as second linearly polarized light and guides it to the second semi-transparent mirror side, and reflects the light reflected by the second semi-transparent mirror and passes through the fourth phase difference plate, transmits it as first linearly polarized light and guides it to the viewing area side.

29. A housing having a viewing section, a first display panel mounting section on which a first display panel for displaying a first display image can be installed, and a second display panel mounting section on which a second display panel for displaying a second display image can be installed, The housing includes an optical system located within the housing that forms a first image based on the first display image, When the inside of the housing is viewed from the viewing section, the first image and at least a portion of the second display image are positioned to overlap. A first display device comprising: a first display panel for displaying the first display image; and a first optical system which is part of the optical system, and which emits a first polarization based on the first display image, thereby enabling the first image to be imaged at a position different from the first display panel; A second display device having the second display panel and emitting a second polarization based on the second display image, A reflective polarizing plate which is part of the optical system, comprising a reflective polarizing plate that reflects the first polarized light emitted from the first display device and guides it to the viewing section, The first polarized light reflected by the reflective polarizing plate and the second polarized light emitted from the second display device are emitted from the viewing unit. A non-user-mounted display panel housing device, wherein the position of the reflective polarizing plate is different from the optical path of the second polarized light emitted from the second display device.

30. It can be installed in a first housing having a first viewing section, and a second housing having a second viewing section, A first display panel located within the second housing and displaying a first display image, A second display panel located within the second housing and displaying a second display image, It comprises an optical system located within the second housing that forms an image of a first image based on the first display image and a second image based on the second display image, When the inside of the second housing is viewed from the second viewing section, the first image and at least a portion of the second image are positioned to overlap. The optical system described above is A reflector, A first reflective polarizing plate is located between the first display panel and the reflector, and between the second display panel and the second viewing section, and transmits first linearly polarized light and reflects second linearly polarized light. A first semi-transparent mirror is positioned between the first display panel and the first reflective polarizing plate, and transmits light incident from the first display panel side and reflects light incident from the first reflective polarizing plate side. A first phase difference plate is located between the first display panel and the first semitransparent mirror, A second phase difference plate is located between the first semi-transparent mirror and the first reflective polarizing plate, A second semi-transparent mirror is positioned between the second display panel and the first reflective polarizer, and transmits light incident from the second display panel side and reflects light incident from the first reflective polarizer side. A third phase difference plate is located between the second display panel and the second semi-transparent mirror, The system comprises a fourth phase difference plate located between the second semi-transparent mirror and the first reflective polarizing plate, The aforementioned reflector reflects light incident from the side of the first reflecting polarizer, The first reflective polarizing plate is Light emitted from the first display panel and transmitted through the first phase difference plate, the first semi-transparent mirror, and the second phase difference plate is transmitted as first linearly polarized light and guided to the reflector side, the light reflected by the reflector is transmitted as first linearly polarized light and guided to the first semi-transparent mirror side, the light reflected by the first semi-transparent mirror and transmitted through the second phase difference plate is reflected as second linearly polarized light and guided to the second viewing section side, A display system comprising: light emitted from the second display panel, transmitted through the third phase difference plate, the second semi-transparent mirror, and the fourth phase difference plate, reflected as second linearly polarized light and guided to the reflector side; light reflected by the reflector, reflected as second linearly polarized light and guided to the second semi-transparent mirror side; and light reflected by the second semi-transparent mirror, transmitted through the fourth phase difference plate, transmitted as first linearly polarized light and guided to the second viewing section side.

31. It can be installed in a first housing having a first viewing section, and a second housing having a second viewing section, A first display panel located within the second housing and displaying a first display image, A second display panel located within the second housing and displaying a second display image, The system comprises an optical system located within the second housing that forms a first image based on the first display image, When the inside of the second housing is viewed from the second viewing unit, the first image and at least a portion of the second display image are positioned to overlap. A first display device comprising: a first display panel for displaying the first display image; and a first optical system which is part of the optical system, and which emits a first polarization based on the first display image, thereby enabling the first image to be imaged at a position different from the first display panel; A second display device having the second display panel and emitting a second polarization based on the second display image, A reflective polarizing plate which is part of the optical system, comprising a reflective polarizing plate that reflects the first polarized light emitted from the first display device and guides it to the second viewing unit, The first polarized light reflected by the reflective polarizing plate and the second polarized light emitted from the second display device are emitted from the second viewing unit. A display system in which the position of the reflective polarizing plate is different from the position on the optical path of the second polarized light emitted from the second display device.

32. A first housing having a first viewing section, A second housing is installed inside the first housing and has a second viewing section, A first display panel located within the second housing and displaying a first display image, A second display panel located within the second housing and displaying a second display image, It comprises an optical system located within the second housing that forms an image of a first image based on the first display image and a second image based on the second display image, When the inside of the second housing is viewed from the second viewing unit through the first viewing unit, the first image and at least a portion of the second image are positioned to overlap. The optical system described above is A reflector, A first reflective polarizing plate is located between the first display panel and the reflector, and between the second display panel and the second viewing section, and transmits first linearly polarized light and reflects second linearly polarized light. A first semi-transparent mirror is positioned between the first display panel and the first reflective polarizing plate, and transmits light incident from the first display panel side and reflects light incident from the first reflective polarizing plate side. A first phase difference plate is located between the first display panel and the first semitransparent mirror, A second phase difference plate is located between the first semi-transparent mirror and the first reflective polarizing plate, A second semi-transparent mirror is positioned between the second display panel and the first reflective polarizer, and transmits light incident from the second display panel side and reflects light incident from the first reflective polarizer side. A third phase difference plate is located between the second display panel and the second semi-transparent mirror, The system comprises a fourth phase difference plate located between the second semi-transparent mirror and the first reflective polarizing plate, The aforementioned reflector reflects light incident from the side of the first reflecting polarizer, The first reflective polarizing plate is Light emitted from the first display panel and transmitted through the first phase difference plate, the first semi-transparent mirror, and the second phase difference plate is transmitted as first linearly polarized light and guided to the reflector side, the light reflected by the reflector is transmitted as first linearly polarized light and guided to the first semi-transparent mirror side, the light reflected by the first semi-transparent mirror and transmitted through the second phase difference plate is reflected as second linearly polarized light and guided to the second viewing section side, A display system comprising: light emitted from the second display panel, transmitted through the third phase difference plate, the second semi-transparent mirror, and the fourth phase difference plate, reflected as second linearly polarized light and guided to the reflector side; light reflected by the reflector, reflected as second linearly polarized light and guided to the second semi-transparent mirror side; and light reflected by the second semi-transparent mirror, transmitted through the fourth phase difference plate, transmitted as first linearly polarized light and guided to the second viewing section side.

33. A first housing having a first viewing section, A second housing is installed inside the first housing and has a second viewing section, A first display panel located within the second housing and displaying a first display image, A second display panel located within the second housing and displaying a second display image, The system comprises an optical system located within the second housing that forms a first image based on the first display image, When the inside of the second housing is viewed from the second viewing unit through the first viewing unit, the first image and at least a portion of the second display image are positioned to overlap. A first display device comprising: a first display panel for displaying the first display image; and a first optical system which is part of the optical system, and which emits a first polarization based on the first display image, thereby enabling the first image to be imaged at a position different from the first display panel; A second display device having the second display panel and emitting a second polarization based on the second display image, A reflective polarizing plate which is part of the optical system, comprising a reflective polarizing plate that reflects the first polarized light emitted from the first display device and guides it to the second viewing unit, The first polarized light reflected by the reflective polarizing plate and the second polarized light emitted from the second display device are emitted from the second viewing unit. A display system in which the position of the reflective polarizing plate is different from the position on the optical path of the second polarized light emitted from the second display device.

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