Virtual image display device and optical unit

Abstract

To make see-through HMDs thinner. [Solution] The virtual image display device comprises a display panel that emits image light and transmits ambient light; a selective reflective film that reflects circularly polarized light in a first rotational direction as circularly polarized light in the first rotational direction and transmits circularly polarized light in a second rotational direction opposite to the first rotational direction as circularly polarized light in the second rotational direction; and a semi-transparent reflective film provided between the display panel and the selective reflective film, which transmits a portion of the incident light and reflects another portion of the incident light. The semi-transparent reflective film partially transmits the image light emitted by the display panel. The selective reflective film reflects the image light that has passed through the semi-transparent reflective film. The semi-transparent reflective film partially reflects the image light that has been reflected by the selective reflective film. The selective reflective film transmits the image light that has been reflected by the semi-transparent reflective film. The semi-transparent reflective film transmits a portion of the ambient light that has passed through the display panel. The selective reflective film transmits the ambient light that has passed through the semi-transparent reflective film.

Description

Technical Field

[0001] The present invention relates to a virtual image display device and an optical unit that enable observation of a virtual image, and in particular, to a see-through type virtual image display device and an optical unit that display a virtual image and transmit external light.

Background Art

[0002] As a see-through type virtual image display device that enables visual recognition of the outside world, a head-mounted display device is known that includes: a frame portion to be mounted on an observer's head; an image source arranged at a position corresponding to a side surface of the observer's head of the frame portion and configured to emit image light related to specific polarized light; and a selective reflection portion arranged at a position corresponding to the observer's eye of the frame portion and configured to selectively reflect only light related to specific polarized light (Patent Document 1).

Prior Art Literature

Patent Literature

[0003]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] To make a head-mounted display (HMD) resemble ordinary eyeglasses in terms of shape, dimensions, and weight, a wider field of view and thinner design are essential. To achieve both a wider field of view and thinner design in an HMD, the component corresponding to the eyeglass lens needs to be plate-shaped. In this case, to ensure the length of the optical path of the optical system that guides the image light representing the virtual image to the wearer's eye, an optical system of the type in which the image light is folded back inside the plate-shaped component is required. Furthermore, in the same optical element contained in such a plate-shaped component, a waveplate is required to change the deflection state of the image light midway, in order to switch between reflection and transmission of the image light before and after the folding. In addition, in a see-through type HMD, it is necessary to transmit external light, which is separated from the image light, to the wearer's eye.

[0005] In view of the above circumstances, one of the objectives of this disclosure is to provide a virtual image display device and optical unit for thinning a see-through HMD. Other challenges and novel features will become apparent from the description herein and the accompanying drawings. [Means for solving the problem]

[0006] According to one embodiment, the virtual image display device includes a display panel that emits image light and transmits ambient light, a selective reflective film that reflects circularly polarized light in a first rotational direction as circularly polarized light in the first rotational direction and transmits circularly polarized light in a second rotational direction opposite to the first rotational direction as circularly polarized light in the second rotational direction, and a semi-transparent reflective film provided between the display panel and the selective reflective film, which transmits a portion of the incident light and reflects another portion of the incident light. The semi-transparent reflective film partially transmits the image light emitted by the display panel. The selective reflective film reflects the image light that has passed through the semi-transparent reflective film. The semi-transparent reflective film partially reflects the image light that has been reflected by the selective reflective film. The selective reflective film transmits the image light that has been reflected by the semi-transparent reflective film. The semi-transparent reflective film transmits a portion of the ambient light that has passed through the display panel. The selective reflective film transmits the ambient light that has passed through the semi-transparent reflective film.

[0007] According to one embodiment, the optical unit includes a display panel that emits image light and transmits ambient light, a selective reflective film that reflects circularly polarized light in a first rotational direction as circularly polarized light in the first rotational direction and transmits circularly polarized light in a second rotational direction opposite to the first rotational direction as circularly polarized light in the second rotational direction, and a semi-transparent reflective film provided between the display panel and the selective reflective film, which transmits a portion of the incident light and reflects another portion of the incident light. The semi-transparent reflective film partially transmits the image light emitted by the display panel. The selective reflective film reflects the image light that has passed through the semi-transparent reflective film. The semi-transparent reflective film partially reflects the image light that has been reflected by the selective reflective film. The selective reflective film transmits the image light that has been reflected by the semi-transparent reflective film. The semi-transparent reflective film transmits a portion of the ambient light that has passed through the display panel. The selective reflective film transmits the ambient light that has passed through the semi-transparent reflective film. [Effects of the Invention]

[0008] According to one embodiment, the see-through type HMD can be made thinner. [Brief explanation of the drawing]

[0009] [Figure 1] This is an external front view illustrating the mounting state of the virtual image display device according to the first embodiment. [Figure 2] This is a conceptual side view illustrating the structure of the display optical system. [Figure 3] This is a conceptual perspective explaining the structure of a CLC element. [Figure 4] This is a perspective view illustrating the positional relationship between a transmissive light source component, a first polarizing plate, a transmissive liquid crystal panel, a second polarizing plate, and a quarter-wave plate. [Figure 5] This is a conceptual enlarged cross-sectional view illustrating the structure of the display unit. [Figure 6] This diagram illustrates the state of light passing through the display device. [Figure 7] This diagram illustrates the state of image light passing through the imaging optical system. [Figure 8] This diagram illustrates the change in the polarization state of image light passing through the imaging optical system. [Figure 9] This diagram illustrates the state of image light passing through the imaging optical system. [Figure 10] This diagram illustrates the state of image light passing through the imaging optical system. [Figure 11] This diagram illustrates the state of image light passing through the imaging optical system. [Figure 12] This is a conceptual enlarged cross-sectional view illustrating the structure of the display unit. [Figure 13] This is a conceptual enlarged cross-sectional view illustrating the structure of the display unit. [Figure 14] This is a time chart illustrating the drive signals used by the drive circuit to drive the transmissive light source element and the time-sequential half-wavelength liquid crystal plate. [Modes for carrying out the invention]

[0010] With reference to the attached drawings, embodiments for implementing the virtual image display device and optical unit according to this disclosure are described below.

[0011] [First Embodiment] The virtual image display devices 100A, 100B and the optical unit 100 according to the first embodiment of the present invention will be described below with reference to Figures 1 to 8.

[0012] Figure 1 is an external front view illustrating the wearing state of a head-mounted display, i.e., a head-mounted display device 200. The head-mounted display device (hereinafter also referred to as HMD) 200 causes the observer or wearer US to perceive an image as a virtual image. In Figure 1, etc., X, Y, and Z are Cartesian coordinate systems, the +X direction corresponds to the lateral direction in which the binocular eyes (EY) of the observer or wearer US wearing the HMD 200 are aligned, the +Y direction corresponds to the upward direction perpendicular to the lateral direction in which the binocular eyes (EY) are aligned for the wearer US, and the +Z direction corresponds to the forward direction or front direction for the wearer US. The ±Y directions are parallel to the vertical axis or the vertical direction.

[0013] The HMD 200 includes a first virtual image display device 100A for the right eye, a second virtual image display device 100B for the left eye, a pair of temples 100C that support the virtual image display devices 100A and 100B, and a user terminal 90 which is an information terminal. The first virtual image display device 100A includes a first display driving unit 102a disposed at an upper portion, and a first display optical system 103a that covers the front of the eye. The second virtual image display device 100B includes a second display driving unit 102b disposed at an upper portion, and a second display optical system 103b that covers the front of the eye. The HMD 200 combining the first virtual image display device 100A and the second virtual image display device 100B is also a virtual image display device in a broad sense. The pair of temples 100C is a mounting member or support device 106 mounted on the head of a wearer US, and supports upper end sides of the pair of display optical systems 103a and 103b via the display driving units 102a and 102b that are integrated in appearance. A combination of the pair of display driving units 102a and 102b is referred to as a driving device 102.

[0014] Figure 2 is a conceptual side view explaining the structure of the first display optical system 103a. The first display optical system 103a includes a plate-shaped display 40 that forms a two-dimensional image, emits image light ML corresponding to the two-dimensional image, and transmits at least part of external light OL, and an imaging optical system 50 that functions as a lens for the image light ML emitted from the display 40 and forms a virtual image. In Figure 2, in order to facilitate understanding of the configuration of the first display optical system 103a, transparent members disposed between constituent elements are omitted, and the intervals between the constituent elements are partially enlarged in the illustration.

[0015] The display device 40 includes a transmissive light source member 10, a display element 20 that forms and emits image light ML, and a quarter-wave plate 30. The transmissive light source member 10 includes a light-emitting portion that generates white backlight BL and a transmissive portion that transmits external light OL. The display device 40 operates by being driven by the driving circuit 81 of the control device 80 incorporated in the first display driving portion 102a or the driving device 102. The display element 20 of the display device 40 is disposed close to the eye EY with the imaging optical system 50 interposed therebetween, enabling observation of a virtual image formed by the image light ML and see-through viewing of the outside world. In the first display optical system 103a, the distance between the eye EY and the imaging optical system 50 along the optical axis AX direction is, for example, approximately 15 mm to 35 mm. Further, the distance between the transmissive liquid crystal panel 22 of the display device 40 and the imaging optical system 50 along the optical axis AX direction is, for example, approximately 3 mm to 20 mm.

[0016] The display element 20 is a plate-shaped member extending along an XY plane perpendicular to the optical axis AX, and includes, in order from the outside, a first polarizing plate 21, a transmissive liquid crystal panel 22 serving as a display panel, and a second polarizing plate 23. The display element 20 has a structure in which a laminate of the polarizing plates 21, 23 and the transmissive liquid crystal panel 22 is integrated by a frame (not shown). Here, the first polarizing plate 21 and the transmissive liquid crystal panel 22 are disposed in proximity to each other within a predetermined distance. Further, the transmissive liquid crystal panel 22 and the second polarizing plate 23 are disposed in proximity to each other within a predetermined distance. The transmissive liquid crystal panel 22 is an imager that forms, in a time-division manner, first image light of a first color component, second image light of a second color component, and third image light of a third color component that constitute the image light ML. Note that the transmissive liquid crystal panel 22 includes a plurality of pixels arranged in a matrix along the XY plane.

[0017] The quarter-wave plate 30 has polarization characteristics such as emitting linearly polarized light in a first direction as circularly polarized light in a first rotation direction, and emitting linearly polarized light in a second direction perpendicular to the first direction as circularly polarized light in a second rotation direction opposite to the first rotation direction. For example, the quarter-wave plate 30 may emit linearly polarized light in the vertical direction (Y direction) as viewed from the eye EY as left-circularly polarized light, and linearly polarized light in the horizontal direction (X direction) as viewed from the eye EY as right-circularly polarized light. Alternatively, for example, the image light ML emitted by the display element 20 may be linearly polarized in the vertical direction (Y direction) as viewed from the eye EY, and the ambient light OL transmitted through the transmissive light source member 10 and the display element 20 may be linearly polarized in the horizontal direction (X direction) as viewed from the eye EY.

[0018] The imaging optical system 50 is positioned on the face side, i.e., the -Z side, relative to the display unit 40 or display element 20, and covers the area in front of the eyes. The imaging optical system 50 is a plate-shaped member extending along the XY plane, and comprises, in order from the outside, a semi-transparent reflective film 51 and a selective reflective film 52. The imaging optical system 50 further comprises one or more transparent members (not shown). The semi-transparent reflective film 51 and the selective reflective film 52 may be formed on the surface of a first transparent member and on the surface of a second transparent member different from the first transparent member, respectively, or on the first surface of the same transparent member and on the second surface facing the first surface, respectively. The imaging optical system 50 has a structure in which the optical elements constituting it, i.e., the semi-transparent reflective film 51 and the selective reflective film 52, are arranged in close proximity to each other with an appropriate interval between them, and these are integrated by a frame (not shown). Such integration stabilizes the optical performance of the imaging optical system 50 and allows the imaging optical system 50 to be made thinner. Furthermore, including the case where a transparent member is placed between the semi-transparent reflective film 51 and the selective reflective film 52, these can be integrated by directly fixing them with an adhesive, or by bringing them into close contact with each other and fixing them at the outer circumference.

[0019] The semi-transparent reflective film 51 transmits a portion of the incident light and reflects another portion of the incident light, regardless of the polarization state of the incident light. Here, the ratio of the intensity of the light transmitted by the semi-transparent reflective film 51 to the intensity of the light reflected by the semi-transparent reflective film 51 is not limited to 1:1, but may be set to any desired value. The semi-transparent reflective film 51 has a concave curved surface toward the selective reflective film 52. Of the incident light from the selective reflective film 52, the reflected light reflected by the semi-transparent reflective film 51 is focused toward the selective reflective film 52 by the positive power of the concave curved surface of the semi-transparent reflective film 51.

[0020] The selective reflective film 52 reflects circularly polarized light in one rotational direction as circularly polarized light in that one rotational direction, and transmits circularly polarized light in the other rotational direction as circularly polarized light in that other rotational direction, depending on the polarization state of the incident light. Note that when a general reflective film, including the semi-transparent reflective film 51, reflects circularly polarized light, the rotational direction of the reflected light is opposite to the rotational direction of the incident light, and the optical properties of the selective reflective film 52 described above are special. Such optical properties can be realized, for example, by producing the selective reflective film 52 using a CLC (Cholesteric Liquid Crystal) element. As shown in Figure 3, the CLC element 60 includes a liquid crystal director 63 provided between two parallel and opposing transparent substrates 61 and 62. The liquid crystal director 63 is an aggregate of liquid crystal molecules oriented in a direction parallel to the plane direction in which the two transparent substrates 61 and 62 extend. In the CLC element 60, the orientation direction of the liquid crystal molecules forms a helical structure 64 that rotates periodically clockwise or counterclockwise when moving from one transparent substrate to the other, with respect to an axis parallel to the direction in which the two transparent substrates face each other. If the circularly polarized light L1 and L3 incident on the CLC element 60 has the same rotation direction as the helical structure 64 of the CLC element 60, it will pass through the CLC element 60 and become light L2 with the same circularly polarized light CP2. If the circularly polarized light CP1 has the opposite rotation direction to the helical structure 64 of the CLC element 60, it will be reflected by the CLC element 60 and become light L4 with the same circularly polarized light CP1. For example, when the selective reflective film 52 reflects left-circularly polarized light, the polarization state of the reflected light reflected by the selective reflective film 52 is the same left-circularly polarized light as immediately before reflection. The left-circularly polarized light reflected by the selective reflective film 52 is reflected again by the semi-transparent reflective film 51 to become right-circularly polarized light and heads towards the selective reflective film 52. Right-circularly polarized light passes through the selective reflective film 52 and heads towards the eye (EY).

[0021] As a result, the imaging optical system 50 functions as a lens for the image light ML emitted from the display element 20. In other words, the imaging optical system 50 comprehensively images multiple pixels contained in the transmissive liquid crystal panel 22, making it possible to observe the image formed on the transmissive liquid crystal panel 22 as a virtual image. On the other hand, the imaging optical system 50 functions as a parallel plate for the external light OL passing through the display element 20. In other words, the external light OL is observed as a direct-view image by passing through the display element 20 in a straight line.

[0022] The second display optical system 103b is optically identical to the first display optical system 103a, or is a horizontally inverted version of the first display optical system 103a, and a detailed explanation is omitted.

[0023] In the first virtual image display device 100A, the optical device excluding the control device 80 is referred to as the optical unit 100. Similarly, in the second virtual image display device 100B, the optical device excluding the control device 80 is also referred to as the optical unit 100.

[0024] Figure 4 is a perspective view illustrating the positional relationship between the transmissive light source member 10, the first polarizer 21, the transmissive liquid crystal panel 22, the second polarizer 23, and the quarter-wave plate 30 in a direction parallel to the optical axis AX for each of the multiple pixels constituting the image represented by the image light ML generated by the transmissive liquid crystal panel 22. In the example of Figure 4, the multiple pixels are arranged in a grid in the X and Y directions, and the optical axis AX is parallel to the Z direction.

[0025] The transmissive light source member 10 comprises a segmented OLED (Organic Light Emitting Diode) panel having a light-emitting region 10A that emits a white backlight BL and a transparent region 10T that transmits ambient light OL. The transmissive light source member 10 may include a plurality of light-emitting regions 10A and a plurality of transparent regions 10T. The light-emitting regions 10A and transparent regions 10T are arranged alternately one by one adjacent to each other in a first arrangement direction included in the XY plane. Furthermore, each light-emitting region 10A and each transparent region 10T extend in a second arrangement direction included in the XY plane and perpendicular to the first arrangement direction. As shown in the example in Figure 4, each light-emitting region 10A and each transparent region 10T may extend in a band shape across the entire transmissive light source member 10 in the second arrangement direction, or the light-emitting regions 10A and transparent regions 10T may be arranged alternately one by one in the first arrangement direction. In the example shown in Figure 4, the first arrangement direction is parallel to the X direction and the second arrangement direction is parallel to the Y direction, but this embodiment is not limited to this example.

[0026] The first polarizing plate 21 selectively transmits linearly polarized light in the first polarization direction from the incident light. In the example in Figure 4, it selectively transmits linearly polarized light in the polarization direction parallel to the X direction.

[0027] The transmissive liquid crystal panel 22 has multiple pixels PX, each pixel PX comprising a first-color subpixel PXs(R), a second-color subpixel PXs(G), a third-color subpixel PXs(B), and a transparent region PXs(T) that transmits ambient light OL. In each pixel PX, the first-color subpixel PXs(R), the second-color subpixel PXs(G), the third-color subpixel PXs(B), and the transparent region PXs(T) are arranged adjacent to each other in the first arrangement direction. The order in which the first-color subpixel PXs(R), the second-color subpixel PXs(G), the third-color subpixel PXs(B), and the transparent region PXs(T) are arranged in the first arrangement direction is not limited. In each pixel PX, the subpixels PXs(R) of the first color, the subpixels PXs(G) of the second color, the subpixels PXs(B) of the third color, and the transparent region PXs(T) that transmits ambient light OL extend in the second arrangement direction. The transparent region PXs(T) may extend in a band shape across multiple adjacent pixels PX in the second arrangement direction, or it may be integrated. In the example configuration in Figure 4, the widths of the subpixels PXs(R), PXs(G), PXs(B) and the transparent region PXs(T) contained in each pixel PX are the same in the first arrangement direction, but this is merely an example and does not limit this embodiment. For example, the ratio of the width of the transparent region PXs(T) in the first arrangement direction to the width of the pixel PX in the first arrangement direction may be arbitrarily changed. Also, the ratios of the widths of the subpixels PXs(R), PXs(G), and PXs(B) in the first arrangement direction to the width of the pixel PX in the first arrangement direction may be arbitrarily changed. However, in all cases, the sub-pixels PXs(R), PXs(G), and PXs(B) are positioned opposite the transparent region PXs(T) so that the backlight BL from the light-emitting region 10A of the transmissive light source member 10 does not enter the transparent region PXs(T) but enters the sub-pixels PXs(R), PXs(G), and PXs(B). Also, the transparent region PXs(T) is positioned opposite the transparent region 10T so that the ambient light OL from the transparent region 10T of the transmissive light source member 10 does not enter the sub-pixels PXs(R), PXs(G), and PXs(B) but enters the transparent region PXs(T).

[0028] The second polarizing plate 23 comprises a first polarization region 23A that selectively transmits linearly polarized light in a first polarization direction, and a second polarization region 23B that selectively transmits linearly polarized light in a second polarization direction perpendicular to the first polarization direction. The second polarizing plate 23 may include a plurality of first polarization regions 23A and a plurality of second polarization regions 23B. The first polarization regions 23A and the second polarization regions 23B are arranged alternately adjacent to each other, one by one, in a first arrangement direction included in the XY plane. Each first polarization region 23A and each second polarization region 23B extends in a second arrangement direction. Each first polarization region 23A and each second polarization region 23B may extend in a band-like manner across the entire second polarizing plate 23 in the second arrangement direction. The pattern showing the positional relationship between the first polarization regions 23A and the second polarization regions 23B in the second polarizing plate 23 is not limited to the regular pattern shown in the example in Figure 4. However, in all cases, the second polarization region 23B is positioned opposite the subpixels PXs(R), PXs(G), and PXs(B) so that the first, second, and third image light emitted by the subpixels PXs(R), PXs(G), and PXs(B) do not enter the first polarization region 23A but enter the second polarization region 23B. Furthermore, the first polarization region 23A is positioned opposite the transparent region 10T and the transparent region PXs(T) so that the ambient light OL transmitted through the transparent region 10T, the first polarizer 21, and the transparent region PXs(T) does not enter the second polarization region 23B but enters the first polarization region 23A.

[0029] The light-emitting region 10A of the transmissive light source member 10 and the subpixels PXs(R), PXs(G), and PXs(B) of the transmissive liquid crystal panel 22 are arranged facing each other. Furthermore, the subpixels PXs(R), PXs(G), and PXs(B) of the transmissive liquid crystal panel 22 and the second polarization region 23B of the second polarizer plate 23 are arranged facing each other. The subpixels PXs(R), PXs(G), and PXs(B) of the transmissive liquid crystal panel 22 are illuminated by the backlight BL emitted from the light-emitting region 10A of the transmissive light source member 10, and emit image light ML. The image light ML becomes a first polarization state by passing through the second polarization region 23B of the second polarizer plate 23. For example, the image light ML in the first polarization state may have linear polarization parallel to a predetermined first polarization direction included in the XY plane.

[0030] The transparent region 10T of the transmissive light source member 10 and the transparent region PXs(T) of the transmissive liquid crystal panel 22 are arranged facing each other. Also, the transparent region PXs(T) of the transmissive liquid crystal panel 22 and the first polarization region 23A of the second polarizer plate 23 are arranged facing each other. The ambient light OL passes through the transparent region 10T of the transmissive light source member 10 and the transparent region PXs(T) of the transmissive liquid crystal panel 22, and then passes through the first polarization region 23A of the second polarizer plate 23, thereby becoming a second polarization state. The ambient light OL in the second polarization state may have linear polarization whose polarization direction is included in the XY plane, is perpendicular to the first polarization direction, and is parallel to the second polarization direction.

[0031] Figure 5 is a conceptual enlarged cross-sectional view illustrating the structure of the display unit 40. Referring to Figure 5, the transmissive light source member 10 supplies white light as a backlight BL to the transmissive liquid crystal panel 22 of the display element 20. The transmissive light source member 10 may generate the white backlight BL by simultaneously generating three-color backlights.

[0032] The display element 20 is positioned on the face side, or -Z side, opposite the transmissive light source member 10 and the first polarizing plate 21. The display element 20 has a transmissive liquid crystal panel 22 and a pair of polarizing plates 21 and 23 that sandwich the transmissive liquid crystal panel 22. In this case, the display element 20 is a modulation element made of, for example, an IPS (in-plane switching) type liquid crystal, and operates in units of pixels PX. Each pixel PX includes a first-color subpixel PXs(R), a second-color subpixel PXs(G), a third-color subpixel PXs(B), and a transparent region PXs(T). The first-color subpixel PXs(R) has a first-color color filter 220r, the second-color subpixel PXs(G) has a second-color color filter 220g, and the third-color subpixel PXs(B) has a third-color color filter 220b. The transparent region PXs(T) does not have a color filter and is colorless. The display element 20 does not rotate the polarization direction of incident light when no electric field is applied, but rotates the polarization direction of incident light when an electric field is applied. In this case, the first polarizer 21 and the second polarization region 23B of the second polarizer 23 are absorption-type polarizers and are arranged so that their polarization directions intersect, or more specifically, are orthogonal. The display element 20 can be switched ON and OFF on a pixel PX basis in response to a drive signal from the drive circuit 81 (see Figure 2), and can partially pass incident light through at any intermediate grayscale between ON and OFF. For this reason, the transmissive liquid crystal panel 22 has not only a liquid crystal layer 221, a common electrode 222, a pixel electrode 223, and a black matrix 225, but also scan lines, signal lines, switch elements, etc., although these are not shown in the figure. However, the pixel electrode 223 can be omitted for the transparent regions PXs(T), and by omitting the pixel electrode 223, the transmittance of the transparent regions PXs(T) to external light OL can be improved. For high resolution, the transmissive liquid crystal panel 22 is preferably manufactured as an HTPS (High-Temperature Poly-Silicon) panel.

[0033] The first color filter 220r selectively transmits the first color of light from the backlight BL. Similarly, the second color filter 220g selectively transmits the second color of light from the backlight BL. Furthermore, the third color filter 220b selectively transmits the third color of light from the backlight BL. For example, the first color is red (r: red) with a wavelength in the range of approximately 620 nm (nanometers) to approximately 750 nm, the second color is green (g: green) with a wavelength in the range of approximately 495 nm to approximately 570 nm, and the third color is blue (b: blue) with a wavelength in the range of approximately 450 nm to approximately 495 nm. Hereafter, for any given light, the portion whose wavelength falls within the range of the first color will be called the wavelength component of the first color of the light, the portion whose wavelength falls within the range of the second color will be called the wavelength component of the second color of the light, and the portion whose wavelength falls within the range of the third color will be called the wavelength component of the third color of the light.

[0034] The first color subpixels PXs(R) apply an intensity controlled by the control device 80 (see Figure 2) to the first color light, which is the wavelength component of the first color contained in the backlight BL, and emit it as the first image light, which is the wavelength component of the first color that constitutes the image light ML, thereby displaying the first image, which represents the intensity distribution of the wavelength component of the first color in the image represented by the image light ML. Similarly, the second color subpixels PXs(G) apply an intensity controlled by the control device 80 to the second color light, which is the wavelength component of the second color contained in the backlight BL, and emit it as the second image light, which is the wavelength component of the second color that constitutes the image light ML, thereby displaying the second image, which represents the intensity distribution of the wavelength component of the second color in the image represented by the image light ML. Furthermore, the third-color subpixels PXs(B) impart an intensity controlled by the control device 80 to the third-color light, which is the wavelength component of the third color contained in the backlight BL, and emit it as the third image light, which is the wavelength component of the third color that constitutes the image light ML. This displays a third image representing the intensity distribution of the wavelength component of the third color in the image represented by the image light ML. Each pixel PX enables the expression of a variety of colors through the combination of the first image light emitted by the first-color subpixels PXs(R), the second image light emitted by the second-color subpixels PXs(G), and the third image light emitted by the third-color subpixels PXs(B).

[0035] The display element 20 or the transmissive liquid crystal panel 22 may rotate the polarization direction of incident light when no electric field is applied, but not when an electric field is applied. In this case, the first polarizing plate 21 and the second polarization region 23B of the second polarizing plate 23 are arranged so that their polarization directions are parallel to each other.

[0036] Figure 6 is a diagram illustrating the state of light passing through the display unit 40. The light-emitting region 10A of the transmissive light source member 10 emits light in response to the control signal from the control device 80 shown in Figure 2, and the backlight BL is emitted toward the display element 20. The backlight BL illuminates the transmissive liquid crystal panel 22 as second linearly polarized light P2, which is transversely polarized or horizontally polarized, via the first polarizing plate 21 of the display element 20. In other words, among the pixels PX that make up the display element 20, the sub-pixels PXs(R), PXs(G), and PXs(B) that face the light-emitting region 10A of the transmissive light source member 10 are illuminated. The image light ML that has passed through the transmissive liquid crystal panel 22 is obtained by rotating the polarization plane of the backlight BL in response to the drive signal, and only first linearly polarized light P1, which is vertically polarized or perpendicularly polarized, is emitted after passing through the second polarization region 23B of the second polarizing plate 23. The image light ML emitted from the subpixels PXs(R), PXs(G), and PXs(B) contained in each pixel PX of the display element 20 is converted from first linearly polarized light P1 to first circularly polarized light CP1 via the quarter-wave plate 30. As an example, the first circularly polarized light CP1 is left-handed circularly polarized light, where the rotation direction of the polarization plane is counterclockwise when viewed from the direction of propagation.

[0037] External light OL passes through the transparent region 10T of the transmissive light source member 10 and is incident on the display element 20. At this time, the transparent region PXs(T) contained in each pixel PX of the display element 20 is transparent to the external light OL, and the second linearly polarized light P2 of the external light OL incident on the transparent region PXs(T) contained in each pixel PX of the display element 20 travels in a straight line through the first polarizer 21, the transparent region PXs(T), and the first polarization region 23A of the second polarizer 23 contained in the display element 20 and is converted to second linearly polarized light P2. The external light OL emitted from the display element 20 passes through the quarter-wave plate 30 and is converted from second linearly polarized light P2 to second circularly polarized light CP2. As an example, the second circularly polarized light CP2 is right-handed circularly polarized light, where the rotation direction of the polarization plane is clockwise when viewed from the direction of propagation. The rotation direction of the second circularly polarized light CP2 is opposite to the rotation direction of the first circularly polarized light CP1.

[0038] Figure 7 is a diagram illustrating the state of the image light ML passing through the imaging optical system 50. In the example of Figure 7, the imaging optical system 50 comprises a semi-transparent reflective film 51, a selective reflective film 52, and transparent members 53 and 54. For example, the first transparent member 53 has a first surface 53a facing the display unit 40 and a second surface 53b facing the first surface 53a, and the semi-transparent reflective film 51 is formed on the second surface 53b of the first transparent member 53. Also, for example, the second transparent member 54 has a third surface 54a facing the second surface 53b of the first transparent member 53 and a fourth surface 54b facing the third surface 54a, and the selective reflective film 52 is formed on the fourth surface 54b of the second transparent member 54. In the example of Figure 7, the first surface 53a of the first transparent member 53 is the incident surface of the imaging optical system 50, and its shape is a plane perpendicular to the optical axis AX. Furthermore, the fourth surface 54b of the second transparent member 54 is the exit surface of the imaging optical system 50, and its shape is a plane perpendicular to the optical axis AX. However, the above configuration is merely an example and does not limit the present disclosure. As another example, the semi-transparent reflective film 51 may be formed on the third surface 54a of the second transparent member 54.

[0039] As shown in Figure 7, the image light ML emitted from the display 40 passes through the semi-transparent reflective film 51, is reflected by the selective reflective film 52, is reflected again by the semi-transparent reflective film 51, and passes through the selective reflective film 52 before being incident on and exiting the imaging optical system 50. Here, when the image light ML from the selective reflective film 52 is reflected by the semi-transparent reflective film 51 and heads towards the selective reflective film 52, the image light ML converges with positive power because the semi-transparent reflective film 51 has a concave curved surface toward the selective reflective film 52. As a result, the image light ML forms an image when it reaches the eye EY.

[0040] Figure 8 illustrates the change in the polarization state of the image light ML passing through the imaging optical system 50. As explained above with reference to Figure 6, the polarization state of the image light ML emitted from the quarter-wave plate 30 of the display unit 40 is first circular polarization CP1. When the image light ML from the quarter-wave plate 30 is incident on the imaging optical system 50, it is incident on the semi-transparent reflective film 51. Of the image light ML incident on the semi-transparent reflective film 51, some of the image light ML is transmitted through the semi-transparent reflective film 51 from the standpoint of intensity, and another portion of the image light ML is reflected by the semi-transparent reflective film 51. Of the image light ML incident on the semi-transparent reflective film 51, the portion reflected by the semi-transparent reflective film 51 does not reach the eye EY, so it is not shown in the figure. Of the image light ML incident on the semi-transparent reflective film 51, the polarization state of the portion transmitted through the semi-transparent reflective film 51 is the same as before it was incident on the semi-transparent reflective film 51, and in the example of Figure 8, it remains first circular polarization CP1.

[0041] The image light ML that has passed through the semi-transparent reflective film 51 is reflected by the selective reflective film 52, which reflects the first circularly polarized light CP1 and transmits the second circularly polarized light CP2. The polarization state of the image light ML reflected by the selective reflective film 52 is the same as before it was reflected by the selective reflective film 52, and in the example in Figure 8, it remains the first circularly polarized light CP1.

[0042] The image light ML reflected by the selective reflective film 52 is incident on the semi-transparent reflective film 51. Of the image light ML incident on the semi-transparent reflective film 51, some of the image light ML is transmitted through the semi-transparent reflective film 51 from an intensity standpoint, while another portion of the image light ML is reflected by the semi-transparent reflective film 51. Of the image light ML incident on the semi-transparent reflective film 51, the portion that is transmitted through the semi-transparent reflective film 51 does not reach the eye EY, so it is not shown in the figure. Of the image light ML incident on the semi-transparent reflective film 51, the polarization state of the portion reflected by the semi-transparent reflective film 51 is circularly polarized light with a rotation direction opposite to that of the polarization state before reflection by the semi-transparent reflective film 51, and in the example of Figure 8, it is the second circularly polarized light CP2.

[0043] The image light ML reflected by the semi-transparent reflective film 51 passes through the selective reflective film 52 and reaches the eye EY. Here, the polarization state of the image light ML that has passed through the selective reflective film 52 is the same as before it was incident on the selective reflective film 52, and in the example of Figure 8, it remains as second circularly polarized CP2.

[0044] Although not shown in Figure 7, as explained with reference to Figure 6, the polarization state of the ambient light OL transmitted through the display unit 40 is second-circular polarization CP2. Of the ambient light OL incident on the imaging optical system 50, the polarization state of the ambient light OL transmitted through the semi-transparent reflective film 51 remains second-circular polarization CP2, as shown in Figure 8. Therefore, the ambient light OL transmitted through the semi-transparent reflective film 51 does not reflect off the selective reflective film 52 and passes through the selective reflective film 52 to reach the eye EY. Here, it is preferable that the refractive indices of the respective transparent members 53 and 54 are the same so as not to impart unnecessary distortion to the ambient light OL reaching the eye EY.

[0045] The virtual image display device 100A, 100B, or optical unit 100 according to the first embodiment described above comprises a display panel 22, a selective reflective film 52, and a semi-transparent reflective film 51. The display panel 22 emits image light ML and transmits ambient light OL. The selective reflective film 52 reflects circularly polarized light CP1 in a first rotational direction as circularly polarized light CP1 in a first rotational direction, and transmits circularly polarized light CP2 in a second rotational direction opposite to the first rotational direction as circularly polarized light CP2 in a second rotational direction. The semi-transparent reflective film 51 is provided between the display panel 22 and the selective reflective film 52, and transmits a portion of the incident light and reflects another portion of the incident light. The semi-transparent reflective film 51 partially transmits the image light ML emitted by the display panel 22. The selective reflective film 52 reflects the image light ML that has passed through the semi-transparent reflective film 51. The semi-transparent reflective film 51 partially reflects the image light ML reflected by the selective reflective film 52. The selective reflective film 52 transmits the image light ML reflected by the semi-transparent reflective film 51. The semi-transparent reflective film 51 transmits a portion of the ambient light OL that has passed through the display panel 22. The selective reflective film 52 transmits the ambient light OL that has passed through the semi-transparent reflective film 51.

[0046] The above-mentioned virtual image display devices 100A, 100B, or optical unit 100 employ a configuration that effectively combines a semi-transparent reflective film 51 having a concave curved surface and a selective reflective film 52 that selectively transmits or reflects circularly polarized light depending on the direction of rotation, thereby enabling the thinning, miniaturization, and weight reduction of the see-through type HMD200.

[0047] [Second Embodiment] The virtual image display devices 100A, 100B, etc. of the second embodiment will be described below. Note that the virtual image display devices 100A, 100B of the second embodiment are partially modified versions of the virtual image display devices 100A, 100B of the first embodiment, and the parts common to the virtual image display devices 100A, 100B of the first embodiment will not be described.

[0048] As shown in Figure 9, the virtual image display devices 100A and 100B of the second embodiment are mainly modified versions of the virtual image display devices 100A and 100B of the first embodiment shown in Figure 7, with the surface shape of the selective reflective film 52 changed from a flat surface to a curved surface. In the example in Figure 9, the selective reflective film 52 has a convex curved surface toward the semi-transparent reflective film 51. In the second embodiment, the surface shape of the semi-transparent reflective film 51 is also appropriately changed from the curved surface of the first embodiment to match the surface shape of the selective reflective film 52. For example, the power of the concave shape of the semi-transparent reflective film 51 may be greater than the power of the convex shape of the selective reflective film 52.

[0049] Furthermore, a third transparent member 55 is added to make the surface of the imaging optical system 50 on the eye side (EY) flat. The third transparent member 55 has a fifth surface 55a facing the fourth surface 54b of the second transparent member 54, and a sixth surface 55b facing the fifth surface 55a. The surface shape of the fifth surface 55a of the third transparent member 55 has the same curved surface as the selective reflective film 52. The sixth surface 55b of the third transparent member 55 has a plane perpendicular to the optical axis AX and forms the surface of the imaging optical system 50 on the eye side (EY). In the first embodiment, the selective reflective film 52 was formed on the fourth surface 54b of the second transparent member 54 on the eye side (EY), but in the second embodiment, the selective reflective film 52 may be formed on the fourth surface 54b of the second transparent member 54, as in the first embodiment, or on the fifth surface 55a of the third transparent member 55.

[0050] In the second embodiment, the function of focusing the image light ML reaching the eye EY is shared between the surface shape of the semi-transparent reflective film 51 and the surface shape of the selective reflective film 52. As a result, in the second embodiment, compared to the first embodiment, further thinning, miniaturization, and weight reduction of the see-through type HMD200 can be achieved.

[0051] [Third Embodiment] The following describes the virtual image display devices 100A, 100B, etc., of the third embodiment. Note that the virtual image display devices 100A, 100B of the third embodiment are partially modified versions of the virtual image display devices 100A, 100B of the first embodiment, and the parts common to the virtual image display devices 100A, 100B of the first embodiment will not be described.

[0052] As shown in Figure 10, the virtual image display devices 100A and 100B of the third embodiment are mainly modified from the virtual image display devices 100A and 100B of the first embodiment shown in Figure 7, by changing the surface shape of the semi-transparent reflective film 51 from a concave curved surface toward the selective reflective film 52 to a concave Fresnel lens shape toward the selective reflective film 52.

[0053] In the third embodiment, the function of focusing the image light ML reaching the eye EY and forming an image is divided between the surface shape of the semi-transparent reflective film 51 and the surface shape of the selective reflective film 52. As a result, in the third embodiment, a significant reduction in the thinness, size, and weight of the see-through type HMD200 can be achieved compared to the first embodiment.

[0054] [Fourth Embodiment] The following describes the virtual image display devices 100A, 100B, etc., of the fourth embodiment. The virtual image display devices 100A, 100B of the fourth embodiment are partially modified versions of the virtual image display devices 100A, 100B of the first, second, or third embodiment; in other words, they are a combination of the second and third embodiments. The parts of the virtual image display devices 100A, 100B of the fourth embodiment that are common with the virtual image display devices 100A, 100B of the first, second, or third embodiment will not be described.

[0055] As shown in Figure 11, the virtual image display devices 100A and 100B of the fourth embodiment are mainly modified from the virtual image display devices 100A and 100B of the first embodiment shown in Figure 7, by changing the surface shape of the selective reflective film 52 from a flat surface to a curved surface, similar to the second embodiment shown in Figure 9. In addition, the surface shape of the semi-transparent reflective film 51 is changed from a concave curved surface toward the selective reflective film 52 to a concave Fresnel lens shape toward the selective reflective film 52, similar to the third embodiment shown in Figure 10. In other words, the virtual image display devices 100A and 100B of the fourth embodiment are mainly modified from the virtual image display devices 100A and 100B of the second embodiment shown in Figure 9, by changing the surface shape of the semi-transparent reflective film 51 from a concave curved surface toward the selective reflective film 52 to a concave Fresnel lens shape toward the selective reflective film 52, similar to the third embodiment shown in Figure 10. To put it another way, the virtual image display devices 100A and 100B of the fourth embodiment are the same as the virtual image display devices 100A and 100B of the third embodiment shown in Figure 10, but mainly the surface shape of the selective reflective film 52 is changed from a flat surface to a curved surface, similar to the second embodiment shown in Figure 9.

[0056] In the fourth embodiment, the function of focusing the image light ML reaching the eye EY and forming an image is shared between the Fresnel lens shape of the semi-transparent reflective film 51 and the curved surface shape of the selective reflective film 52. As a result, in the fourth embodiment, further thinning, miniaturization, and weight reduction of the see-through type HMD200 can be achieved compared to the first, second, or third embodiment.

[0057] [Variation example: Time-division type display] Of the virtual image display devices 100A and 100B of the embodiments described above, the display 40 shown in Figure 5 can be replaced with the time-division type display 40 shown in Figures 12 and 13. The display 40 in Figures 12 and 13 can be obtained by changing the configuration of the transmissive light source member 10 of the display 40 in Figure 5, removing the color filters 220r, 220g, and 220b from the transmissive liquid crystal panel 22, changing the first polarization region 23A shown in Figure 4 of the second polarizing plate 23 to the second polarization region 23B, and adding a time-sequential half-wavelength liquid crystal plate 24 between the second polarizing plate 23 and the quarter-wavelength plate 30.

[0058] In the display unit 40 shown in Figures 12 and 13, the transmissive light source member 10 comprises a first transmissive light source member 10R that generates a first-color backlight BLr, a second transmissive light source member 10G that generates a second-color backlight BLg, and a third transmissive light source member 10B that generates a third-color backlight BLb. For example, the first transmissive light source member 10R generates red light as the first-color backlight BLr, the second transmissive light source member 10G generates green light as the second-color backlight BLg, and the third transmissive light source member 10B generates blue light as the third-color backlight BLb. Note that each of the first transmissive light source member 10R, the second transmissive light source member 10G, and the third transmissive light source member 10B may generate backlights BLr, BLg, and BLb from their entire surface without having the transparent region 10T that the transmissive light source member 10 shown in Figure 4 has.

[0059] Each of the first transmissive light source member 10R, the second transmissive light source member 10G, and the third transmissive light source member 10B is driven and operated by the drive circuit 81 of the control device 80 shown in Figure 2. The first transmissive light source member 10R, the second transmissive light source member 10G, and the third transmissive light source member 10B in Figures 12 and 13 switch between a light-emitting state and a transmission state in a time-division manner under the control of the control device 80 in Figure 2. In the light-emitting state, the first transmissive light source member 10R, the second transmissive light source member 10G, and the third transmissive light source member 10B in Figures 12 and 13 generate backlights BLr, BLg, and BLb, respectively, and in the transmission state, transmits ambient light OL without generating backlights BLr, BLg, and BLb. The second transmissive light source member 10G in Figures 12 and 13 may further transmit backlight BLr in the transmission state. Furthermore, the third transmissive light source member 10B in Figures 12 and 13 may further transmit backlights BLr and BLg when in the transmissive state.

[0060] The second polarizer 23 in Figures 12 and 13 has a second polarization region 23B, as shown in Figure 4, across its entire surface, and does not have a first polarization region 23A. As explained with reference to Figure 4, the second polarization region 23B transmits only the first linearly polarized light P1 of the incident light. In the example in Figure 4, the first linearly polarized light P1 is longitudinally polarized or perpendicularly polarized. Therefore, the polarization state of the image light ML and the ambient light OL transmitted through the second polarizer 23 in Figures 12 and 13 is the first linearly polarized light P1, which is, for example, longitudinally polarized or perpendicularly polarized.

[0061] The time-sequential half-wavelength liquid crystal plate 24 in Figures 12 and 13 switches between an ON state and an OFF state in a time-division manner under the control of the control device 80 in Figure 2. In the ON state, the time-sequential half-wavelength liquid crystal plate 24 in Figures 12 and 13 transmits the image light ML of the first linearly polarized P1 that has passed through the second polarizer 23 as the first linearly polarized P1. In the OFF state, it functions as a half-wave plate, converting the external light OL of the first linearly polarized P1 that has passed through the second polarizer 23 into a second linearly polarized P2 and emitting it. As an example, the time-sequential half-wavelength liquid crystal plate 24 in Figures 12 and 13 may be constructed using a ferroelectric liquid crystal.

[0062] Referring to the time chart in Figure 14, the drive signals that the drive circuit 81 in Figure 2 drives the first transmissive light source member 10R, the second transmissive light source member 10G, the third transmissive light source member 10B, and the time-sequential half-wavelength liquid crystal panel 24 in Figures 12 and 13 will be explained. The horizontal axis represents time, and from top to bottom, it shows the first flashing signal SS1, the first video signal SM1, the second flashing signal SS2, the second video signal SM2, the third flashing signal SS3, the third video signal SM3, and the on / off signal SW. The first flashing signal SS1 causes the first transmissive light source member 10R of the first color (e.g., R, red) to emit light. The first video signal SM1 causes the transmissive liquid crystal panel 22 to form first-color video light. The second flashing signal SS2 causes the second transmissive light source member 10G of the second color (e.g., G, green) to emit light. The second video signal SM2 causes the transmissive liquid crystal panel 22 to form second-color video light. The third flashing signal SS3 causes the third transmissive light source member 10B of the third color (e.g., B, blue) to emit light. The third video signal SM3 causes the transmissive liquid crystal panel 22 to form a third video light. The on / off signal SW switches the on and off states of the time-sequential half-wavelength liquid crystal plate 24. Each of the frame periods Tf1, Tf2, and Tf3 includes the first color video observation period Tr, the second color video observation period Tg, the third color video observation period Tb, and the ambient light observation period Tt. The drive circuit 81 of the control device 80 shown in Figure 2 outputs flashing signals SS1, SS2, and SS3 to control the operation of the transmissive light source members 10R, 10G, and 10B, respectively, outputs video signals SM1, SM2, and SM3 to control the operation of the transmissive liquid crystal panel 22, and outputs the on / off signal SW to control the operation of the time-sequential half-wavelength liquid crystal plate 24.

[0063] During the first-color image observation period Tr, the first transmissive light source member 10R generates the first-color backlight BLr. The second transmissive light source member 10G and the third transmissive light source member 10B transmit the first-color backlight BLr without generating the second-color backlight BLg and third-color backlight BLb. The transmissive liquid crystal panel 22 transmits the first-color backlight BLr and emits the first-color image light, which represents the first-color component of the image light ML. The time-sequential half-wavelength liquid crystal plate 24 turns on and emits the first-color image light as the image light ML, as first linearly polarized P1.

[0064] During the second-color image observation period Tg, the first transmissive light source member 10R does not generate the first-color backlight BLr. The second transmissive light source member 10G generates the second-color backlight BLg. The third transmissive light source member 10B transmits the second-color backlight BLg without generating the third-color backlight BLb. The transmissive liquid crystal panel 22 transmits the second-color backlight BLg and emits second-color image light representing the second-color component of the image light ML. The time-sequential half-wavelength liquid crystal plate 24 turns on and emits the second-color image light as image light ML as first linearly polarized P1.

[0065] During the third-color image observation period Tb, the first transmissive light source member 10R and the second transmissive light source member 10G do not generate the first-color backlight BLr and the second-color backlight BLg. The third transmissive light source member 10B generates the third-color backlight BLb. The transmissive liquid crystal panel 22 transmits the third-color backlight BLb and emits third-color image light representing the third-color component of the image light ML. The time-sequential half-wavelength liquid crystal plate 24 turns on and emits the third-color image light as image light ML as first linearly polarized P1.

[0066] During the ambient light observation period Tt, the first transmissive light source member 10R, the second transmissive light source member 10G, and the third transmissive light source member 10B transmit ambient light OL without emitting the first-color backlight BLr, the second-color backlight BLg, and the third-color backlight BLb. The transmissive liquid crystal panel 22 transmits ambient light OL without emitting the first, second, and third color components of the image light ML. The time-sequential half-wavelength liquid crystal plate 24 is turned off and converts the ambient light OL, which is first linearly polarized P1, into second linearly polarized P2 and emits it.

[0067] As explained above, in the modified configurations of the first to fourth embodiments, in which the time-division display 40 shown in Figures 12 and 13 is combined with the imaging optical system 50 shown in Figures 7, 9, 10, and 11, the image light ML emitted from the display 40 and the ambient light OL transmitted through the display 40 are superimposed and can reach the eye EY for observation. This is because, even in this modified configuration, the image light ML has first circular polarization CP1 when emitted from the display 40 and reaches the eye EY in an imaged state by the imaging optical system 50, and the ambient light OL has second circular polarization CP2 when transmitted through the display 40 and passes through the imaging optical system 50 to reach the eye EY.

[0068] A virtual image display device in a specific embodiment includes a display panel that emits projected light and transmits ambient light; a selective reflective film that reflects circularly polarized light in a first rotational direction as circularly polarized light in the first rotational direction and transmits circularly polarized light in a second rotational direction opposite to the first rotational direction as circularly polarized light in the second rotational direction; and a semi-transparent reflective film provided between the display panel and the selective reflective film, which transmits a portion of the incident light and reflects another portion of the incident light. The semi-transparent reflective film partially transmits the image light emitted by the display panel. The selective reflective film reflects the image light that has passed through the semi-transparent reflective film. The semi-transparent reflective film partially reflects the image light that has been reflected by the selective reflective film. The selective reflective film transmits the image light that has been reflected by the semi-transparent reflective film. The semi-transparent reflective film transmits a portion of the ambient light that has passed through the display panel. The selective reflective film transmits the ambient light that has passed through the transmissive reflective film.

[0069] In the above-mentioned virtual image display device, a see-through HMD that transmits ambient light can be made thinner by combining a semi-transparent reflective film and a selective reflective film.

[0070] In a specific embodiment, the virtual image display device further comprises a quarter-wave plate that converts linearly polarized light in a first direction from the image light and ambient light into circularly polarized light in a first rotational direction, and converts linearly polarized light in a second direction orthogonal to the first direction into circularly polarized light in a second rotational direction.

[0071] In the above virtual image display device, by using a quarter-wave plate that converts linearly polarized light with different polarization directions into circularly polarized light with different rotation directions, two types of circularly polarized light can be reflected or transmitted by a selective reflective film.

[0072] A virtual image display device in a specific embodiment further comprises: a display panel and a semi-transparent reflective film, and a first transparent member having a first surface facing the display panel and a second surface facing the semi-transparent reflective film; and a second transparent member having a semi-transparent reflective film and a selective reflective film, and a third surface facing the semi-transparent reflective film and a fourth surface facing the selective reflective film. The semi-transparent reflective film is formed on at least one of the second surface of the first transparent member and the third surface of the second transparent member.

[0073] In the above-described virtual image display device, the relative positions of the semi-transparent reflective film and the selective reflective film can be fixed by forming them on the surface of a transparent member.

[0074] In a specific embodiment of a virtual image display device, the semi-transparent reflective film has a first curved surface that is concave toward the selective reflective film.

[0075] In a specific embodiment of a virtual image display device, the semi-transparent reflective film has a Fresnel lens shape that is concave toward the selective reflective film.

[0076] In the above-described virtual image display device, the semi-transparent reflective film can focus the image light with positive power to form an image.

[0077] In a specific embodiment of the virtual image display device, the selective reflective film is formed on the fourth surface of the second transparent member.

[0078] In a specific embodiment, the virtual image display device further comprises a third transparent member having a fifth surface facing the fourth surface of the second transparent member and a sixth surface facing the fifth surface, the second transparent member being positioned between the first transparent member and the third transparent member, and a selective reflective film being formed on the fourth surface of the second transparent member or the fifth surface of the third transparent member, the selective reflective film having a second curved surface that is convex toward the semi-transparent reflective film.

[0079] In the above-described virtual image display device, by forming a semi-transparent reflective film and a selective reflective film on the surface of a transparent member, the positional relationship between the semi-transparent reflective film and the selective reflective film can be fixed, and the semi-transparent reflective film can focus the image light with positive power to form an image.

[0080] In a specific embodiment, the optical unit comprises a display panel that emits projected light and transmits ambient light; a selective reflective film that reflects circularly polarized light in a first rotational direction as circularly polarized light in the first rotational direction and transmits circularly polarized light in a second rotational direction opposite to the first rotational direction as circularly polarized light in the second rotational direction; and a semi-transparent reflective film provided between the display panel and the selective reflective film, which transmits a portion of the incident light and reflects another portion of the incident light. The semi-transparent reflective film partially transmits the image light emitted by the display panel. The selective reflective film reflects the image light that has passed through the semi-transparent reflective film. The semi-transparent reflective film partially reflects the image light that has been reflected by the selective reflective film. The selective reflective film transmits the image light that has been reflected by the semi-transparent reflective film. The semi-transparent reflective film transmits a portion of the ambient light that has passed through the display panel. The selective reflective film transmits the ambient light that has passed through the transmissive reflective film.

[0081] The above optical unit allows for the thinning of a see-through HMD that transmits ambient light by combining a semi-transparent reflective film and a selective reflective film. [Explanation of Symbols]

[0082] 10...Transmissive light source component, 10A...Light-emitting region, 10B...Third transmissive light source component, 10G...Second transmissive light source component, 10R...First transmissive light source component, 10T...Transparent region, 20...Display element, 21...Polarizing plate, 22...Transmissive liquid crystal panel, 220b, 220g, 220r...Color filters, 221...Liquid crystal layer, 222...Common electrode, 223...Pixel electrode, 225...Black matrix, 23... Polarizing plate, 23A, 23B… Polarization region, 24… Time-sequential half-wavelength liquid crystal plate, 30… Quarter-wave plate, 40… Display unit, 50… Imaging optical system, 51… Semi-transparent reflective film, 52… Selective reflective film, 53, 54, 55… Transparent material, 60… CLC element, 61, 62… Transparent substrate, 63… Liquid crystal director, 64… Helical structure, 80… Control device, 81… Drive circuit, 90… User terminal, 100A, 100B …Virtual image display device, 100C…Temple, 102…Drive unit, 102a,102b…Display drive unit, 103a,103b…Display optical system, 106…Support device, 200…HMD, Head-mounted display, Head-worn display device, AX…Optical axis, BL…Backlight, BLb…Third color backlight, BLg…Second color backlight, BLr…First color backlight, CP1,CP2… Circular polarization, EY...eye, binoculars, L1, L2, L3, L4...light, ML...image light, OL...external light, P1, P2...linear polarization, PX...pixel, PXs(B), PXs(G), PXs(R)...subpixel, PXs(T)...transparent region, Tb...third color display period, Tg...second color display period, Tf1, Tf2, Tf3...frame period, Tr...first color display period, US...observer, wearer, X, Y, Z...direction.

Claims

1. A display panel that emits image light and transmits ambient light, A selective reflective film that reflects circularly polarized light in a first rotational direction as circularly polarized light in the first rotational direction, and transmits circularly polarized light in a second rotational direction opposite to the first rotational direction as circularly polarized light in the second rotational direction, A semi-transparent reflective film is provided between the display panel and the selective reflective film, which transmits a portion of the incident light and reflects another portion of the incident light. Equipped with, The semi-transparent reflective film partially transmits the image light emitted by the display panel. The selective reflective film reflects the image light that has passed through the semi-transparent reflective film. The semi-transparent reflective film partially reflects the image light reflected by the selective reflective film. The selective reflective film transmits the image light reflected by the semi-transparent reflective film. The semi-transparent reflective film allows a portion of the external light that has passed through the display panel to pass through. The selective reflective film transmits the external light that has passed through the semi-transparent reflective film. Virtual image display device.

2. A quarter-wave plate converts linearly polarized light in a first direction and circularly polarized light in a first rotational direction, and linearly polarized light in a second direction perpendicular to the first direction, into circularly polarized light in a second rotational direction. Furthermore, The virtual image display device according to claim 1.

3. A first transparent member is disposed between the display panel and the semi-transparent reflective film, and has a first surface facing the display panel and a second surface facing the semi-transparent reflective film. A second transparent member is disposed between the semi-transparent reflective film and the selective reflective film, and has a third surface facing the semi-transparent reflective film and a fourth surface facing the selective reflective film. Furthermore, The semi-transparent reflective film is formed on at least one of the second surface of the first transparent member and the third surface of the second transparent member. The virtual image display device according to claim 1.

4. The semi-transparent reflective film has a first curved surface that is concave toward the selective reflective film. The virtual image display device according to claim 3.

5. The semi-transparent reflective film has a Fresnel lens shape that is concave toward the selective reflective film. The virtual image display device according to claim 3.

6. The selective reflective film is formed on the fourth surface of the second transparent member. The virtual image display device according to claim 3.

7. The third transparent member further comprises a fifth surface facing the fourth surface of the second transparent member and a sixth surface facing the fifth surface, The second transparent member is positioned between the first transparent member and the third transparent member. The selective reflective film is formed on the fourth surface of the second transparent member or the fifth surface of the third transparent member. The selective reflective film has a second curved surface that is convex toward the semi-transparent reflective film. The virtual image display device according to claim 4 or 5.

8. The power of the concave shape of the semi-transparent reflective film is greater than the power of the convex shape of the selective reflective film. The virtual image display device according to claim 7.

9. A display panel that emits image light and transmits ambient light, A selective reflective film that reflects circularly polarized light in a first rotational direction as circularly polarized light in the first rotational direction, and transmits circularly polarized light in a second rotational direction opposite to the first rotational direction as circularly polarized light in the second rotational direction, A semi-transparent reflective film is provided between the display panel and the selective reflective film, which transmits a portion of the incident light and reflects another portion of the incident light. Equipped with, The semi-transparent reflective film partially transmits the image light emitted by the display panel. The selective reflective film reflects the image light that has passed through the semi-transparent reflective film. The semi-transparent reflective film partially reflects the image light reflected by the selective reflective film. The selective reflective film transmits the image light reflected by the semi-transparent reflective film. The semi-transparent reflective film allows a portion of the external light that has passed through the display panel to pass through. The selective reflective film transmits the external light that has passed through the semi-transparent reflective film. Optical unit.

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