Virtual image display device and optical unit

Abstract

To make the imaging system of a virtual image display device thinner. [Solution] The virtual image display device 100A, 100B, or optical unit 100 includes a display 40 that emits circularly polarized image light ML and transmits ambient light OL, and a polarizing diffraction lens 51 having a diffraction region 51a that focuses the image light ML emitted from the display 40 and a non-diffraction region 51b that transmits ambient light OL that passes through the display 40.

Description

[[Technical Field]]

[0001] The present invention relates to a virtual image display device and an optical unit that enable observation of virtual images, and particularly relates to a virtual image display device and the like using a polarization diffraction lens. [[Background Art]]

[0002] A polarization conversion system including a geometric phase element and a retarder element is known in the art (see Patent Document 1). The geometric phase element has optical anisotropy including a local optical axis direction that non-linearly changes in at least one dimension along a surface thereof. The retarder element is disposed so as to receive light output from the geometric phase element. [[Prior Art Documents]] [[Patent Documents]]

[0003] [[Patent Document 1]] Japanese National Publication of International Patent Application No. 2016-519327 [[Summary of the Invention]] [[Problem to be Solved by the Invention]]

[0004] Among the above-mentioned polarization conversion systems, the geometric phase element exerts a condensing effect on right-handed circularly polarized light and a diverging effect on left-handed circularly polarized light. Therefore, even if the system of Patent Document 1 is simply applied to a virtual image display device, it is difficult to achieve both image observation and external light observation. In the case of a see-through type virtual image display device, the geometric phase element needs to be disposed at a position outside the see-through region, which causes a problem that the optical system increases in size. [[Means for Solving the Problem]]

[0005] A virtual image display device and an optical unit according to one aspect of the present invention includes: a display that emits circularly polarized image light and transmits external light; and a polarization diffraction lens having a diffraction region that condenses the image light emitted from the display, and a non-diffraction region that transmits the external light passing through the display. [Brief explanation of the drawing]

[0006] [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 perspective view illustrating the structure of a virtual image display device. [Figure 3] This is a conceptual side cross-sectional view illustrating the configuration of the display optical system. [Figure 4] This is a conceptual diagram illustrating the process by which light rays travel from the outside world to reach the eye. [Figure 5] This is a rear view illustrating the image display panel. [Figure 6] This is a rear view illustrating the polarizing element. [Figure 7] This is a rear view illustrating a polarizing diffraction lens. [Figure 8] This is a diagram illustrating the function of polarizing diffraction lenses. [Figure 9] This diagram illustrates the state of light in a display optical system. [Figure 10] This is a rear view illustrating the polarizing diffraction lens of the virtual image display device according to the second embodiment. [Figure 11] Figure 10 illustrates a modified example of the polarizing diffraction lens shown. [Figure 12] This is a rear view illustrating the polarizing element of the virtual image display device according to the third embodiment. [Figure 13] This is a conceptual perspective view illustrating the structure of the virtual image display device according to the fourth embodiment. [Figure 14] Figure 13 is a conceptual side cross-sectional view illustrating the configuration of the display optical system. [Figure 15] Figure 13 is a diagram illustrating the state of light in the display optical system shown. [Figure 16] Figure 13 is a chart illustrating the operation of the virtual image display device. [Figure 17] This is a conceptual side cross-sectional view illustrating a modified example of the display shown in Figure 13. [Modes for carrying out the invention]

[0007] [First Embodiment] A virtual image display device according to the first embodiment of the present invention will be described below with reference to the drawings.

[0008] Figure 1 is a 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.

[0009] The HMD200 comprises 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 consists of a first display drive unit 102a located at the top and a first display optical system 103a that covers the area in front of the eyes. The second virtual image display device 100B consists of a second display drive unit 102b located at the top and a second display optical system 103b that covers the area in front of the eyes. The HMD200, which combines 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 are mounting members or support devices 106 that are attached to the head of the wearer US, and support the upper ends of the pair of display optical systems 103a and 103b via the display drive units 102a and 102b, which are integrated in appearance. The combination of the pair of display drive units 102a and 102b is called the drive unit 102.

[0010] Fig. 2 is a conceptual perspective view illustrating the structure of a first display optical system 103a of a first virtual image display device 100A. Fig. 3 is a conceptual side cross-sectional view illustrating the configuration of the first display optical system 103a. Fig. 3 is also a conceptual diagram illustrating light rays until image light ML reaches an eye EY in the first display optical system 103a. Fig. 4 is a conceptual diagram illustrating light rays until external light OL reaches the eye EY in the first display optical system 103a.

[0011] The first display optical system 103a includes: a plate-shaped display 40 that forms a two-dimensional image and emits image light ML corresponding to the two-dimensional image; and an imaging system 50 that functions as a lens for the image light ML emitted from the display 40 and forms a virtual image.

[0012] The display 40 emits circularly polarized image light ML and transmits external light OL. The display 40 includes a composite display member 20 that forms and emits the image light ML. The composite display member 20 is a plate-shaped member extending along an XY plane perpendicular to an optical axis AX, and includes an image display panel 25 serving as a display member 2b and a polarizing element 26 in order from the display 40 side. The composite display member 20 has a structure in which a layered body of the image display panel 25 and the polarizing element 26 is integrated by a frame (not shown). In the present embodiment, the image display panel 25 and the polarizing element 26 function as a light separating member 41 that separates the image light ML and the external light OL into different light components. As will be described in detail later, the different light components mean that the image light ML is circularly polarized light condensed by the imaging system 50, and the external light OL is not circularly polarized light. The external light OL is, for example, non-polarized light or linearly polarized light.

[0013] The display 40 operates by being driven by the first display driving section 102a or the driving circuit 81 of the control device 80 incorporated in the driving device 102. The composite display member 20 of the display 40 is disposed close to the eye EY with the imaging system 50 interposed therebetween, and enables observation of a virtual image 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 system 50 in the direction of the optical axis AX is, for example, approximately 10 mm to 20 mm. Further, the distance between the image display panel 25 of the display 40 and the imaging system 50 in the direction of the optical axis AX is, for example, approximately 5 mm to 25 mm.

[0014] The image display panel 25 is a self-luminous image light generating device that emits red, green, and blue image light ML. The image display panel 25 is an imager 2a that forms a still image or a moving image on a two-dimensional display surface parallel to the XY plane. The image display panel 25 performs a display operation by being driven by the driving circuit 81.

[0015] The image display panel 25 is, for example, a transmissive organic light-emitting diode (OLED) display, but may also be a micro light-emitting diode (μLED) display formed of an inorganic material, or other self-luminous display device having transparency. Note that, instead of the image display panel 25, a configuration may be adopted in which the image light ML is projected onto a transparent screen using a projection optical system.

[0016] FIG. 5 is a rear view for explaining the image display panel 25. The image display panel 25 includes, on a light-transmissive flat plate 25p, a display region 25a that forms the image light ML, and a first external light transmission region 25b that transmits external light OL. In the flat plate 25p, the plurality of display regions 25a and the plurality of first external light transmission regions 25b are arranged in a matrix along the XY plane. In other words, in a plan view, the display regions 25a and the first external light transmission regions 25b are alternately arranged.

[0017] The display region 25a is a light-emitting region 5a provided with pixels PX. One display region 25a corresponds to one pixel PX, and has sub-pixels of three RGB colors arranged therein.

[0018] The display area 25a is not limited to a group of pixels having subpixels of the three colors RGB, but may also consist of individual R pixels, G pixels, or B pixels. In this case, the first external light transmission area 25b may be arranged, for example, at a ratio of one for every three display areas 25a (R pixels, G pixels, or B pixels).

[0019] The first external light transmission region 25b is a non-display area where no pixels PX are provided, and it transmits ambient light OL directly. The first external light transmission region 25b is, for example, the light-transmitting plate 25p itself, or an aperture formed in the plate 25p. The size of the first external light transmission region 25b is, for example, a square region with sides of 3 μm to 20 μm. The shape of the first external light transmission region 25b is not limited to a square; it may be a rectangle, a quadrilateral with rounded corners, a circle, or an ellipse.

[0020] Figure 6 is a rear view illustrating the polarizing element 26. The polarizing element 26 is a light-transmitting flat plate 26p having a polarization region 26a that restricts image light ML to a predetermined polarization direction and a second external light transmission region 26b that transmits external light OL. On the flat plate 26p, a plurality of polarization regions 26a and a plurality of second external light transmission regions 26b are arranged in a matrix along the XY plane. In other words, in a plan view, the polarization regions 26a and the second external light transmission regions 26b are arranged alternately. The polarization regions 26a are positioned in a location corresponding to the display region 25a of the image display panel 25. The second external light transmission regions 26b are positioned in a location corresponding to the first external light transmission region 25b of the image display panel 25.

[0021] The polarization region 26a has, in order from the display unit 40 side, a polarizing plate 6a and a quarter-wave plate 6b. The polarization region 26a converts the image light ML into linearly polarized light in a predetermined polarization direction, and then into circularly polarized light.

[0022] The polarizing plate 6a restricts the image light ML to a first polarization P1 with a predetermined polarization direction, specifically, longitudinal polarization or perpendicular polarization. The polarizing plate 6a is, for example, a wire grid type polarizing element, and has polarization characteristics corresponding to the pattern direction of a fine metallic grid made of aluminum or the like.

[0023] The quarter-wave plate 6b has its principal axis, for example, midway between the X and Y directions, and converts the image light ML from linearly polarized to circularly polarized. Here, the statement that the image light ML is circularly polarized means that, when focusing on the vibration of the electric field component or magnetic field component of the image light ML, the direction of vibration rotates at the frequency of the image light ML in a plane perpendicular to the direction of light propagation, and the amplitude is constant regardless of the direction. Right-handed circular polarization means that, as viewed from an observer standing facing the direction from which the light ray is traveling, the direction of vibration of the electric field component rotates clockwise, and left-handed circular polarization means it rotates counterclockwise. However, in this specification, if the image light ML mainly contains right-handed circular polarization, even if it contains linear polarization in a specific direction, such image light ML is considered to be right-handed circularly polarized RCP. Similarly, if the image light ML mainly contains left-handed circular polarization, such image light ML is considered to be left-handed circularly polarized LCP. In this specification, right-handed circularly polarized RCP is also referred to as right-circularly polarized RCP, and left-handed circularly polarized LCP is also referred to as left-circularly polarized LCP. The quarter-wave plate 6b may be made by coating a photocrosslinkable polymer liquid crystal material onto a transparent resin substrate to form a thin film and fix its orientation, or it may be made by processing a birefringent crystalline material such as quartz into a thin plate.

[0024] The second external light transmission region 26b is an unpolarized region that transmits ambient light OL as is, and is, for example, the light-transmitting flat plate 26p itself, or an opening formed in the flat plate 26p. Considering assembly accuracy and the like, it is desirable that the size of the external light transmission region 26b be, for example, about 10% larger than the size of the first external light transmission region 25b of the image display panel 25. However, the size of the second external light transmission region 26b may be the same as the size of the first external light transmission region 25b. The shape of the second external light transmission region 26b is not limited to a square, but may be a rectangle, a quadrilateral with rounded corners, a circle, or an ellipse.

[0025] In the above configuration, the video light ML becomes circularly polarized by passing through the display area 25a of the image display panel 25, which is the display component 2b, and the polarization area 26a of the polarizing element 26. The ambient light OL becomes a different light component from the video light ML by passing through the first ambient light transmission area 25b of the image display panel 25, which is the display component 2b, and the second ambient light transmission area 26b of the polarizing element 26.

[0026] Returning to Figure 2, the imaging system 50 is positioned on the face side, or -Z side, relative to the display unit 40 or composite display member 20, and covers the area in front of the eyes. The imaging system 50 functions as a positive lens or collimator with positive power for the image light ML. The imaging system 50 includes a polarizing diffracting lens 51. The polarizing diffracting lens 51 is an optical element whose function differs depending on the polarization.

[0027] Figure 7 is a rear view illustrating the polarizing diffracting lens 51. The polarizing diffracting lens 51 is a plate-shaped member extending along the XY plane. The polarizing diffracting lens 51 has a flat plate 51p with diffracting regions 51a that diffract and focus image light ML, and non-diffracting regions 51b that transmit ambient light OL. On the flat plate 51p, multiple non-diffracting regions 51b are arranged in a matrix along the XY plane. In other words, in a plan view, the polarizing diffracting lens 51 has multiple non-diffracting regions 51b arranged in an island-like manner, and the diffracting regions 51a are arranged in the remaining region. As a result, ambient light OL that has passed through the island-like non-diffracting regions 51b reaches the eye EY without being diffracted.

[0028] The polarizing diffracting lens 51, specifically the diffracting region 51a, has a refractive power that selectively acts on the polarization of the image light ML. In other words, the diffracting region 51a of the polarizing diffracting lens 51 functions as a lens for the image light ML emitted from the display unit 40. That is, the diffracting region 51a comprehensively images multiple pixels constituting the image display panel 25, making it possible to observe the image formed on the image display panel 25 as a virtual image. On the other hand, the non-diffracting region 51b of the polarizing diffracting lens 51 functions as a parallel plate or transmission region for the external light OL passing through the display unit 40. As a result, the external light OL is observed as a direct-view image by passing through the non-diffracting region 51b of the polarizing diffracting lens 51 in a straight line.

[0029] The diffraction region 51a of the polarizing diffraction lens 51 functions as a positive lens on its own when a predetermined circularly polarized light is incident on it. The polarizing diffraction lens 51 functions as a negative lens on its own when a circularly polarized light that is the opposite of the predetermined circularly polarized light is incident on it. The polarizing diffraction lens 51 includes a liquid crystal layer in which the rotation angle of the orientation axis of the liquid crystal molecules increases as it moves away from the optical axis AX, and this is repeated periodically, so that an initial geometric phase is formed. The direction of increase in the rotation angle of the orientation axis of the liquid crystal molecules in the polarizing diffraction lens 51 is polarization-dependent. The polarizing diffraction lens 51 is also called a liquid crystal diffraction lens, a GP (geometric-phase) lens, a two-dimensional anisotropic diffractive optical element, or a geometric phase lens.

[0030] The non-diffraction region 51b is a region that transmits ambient light OL as is, and is, for example, an aperture formed in the flat plate 51p of the polarizing diffraction lens 51, or a region in the polarizing diffraction lens 51 where the arrangement of liquid crystal molecules is disordered. In this embodiment, the size of the non-diffraction region 51b is the same as or approximately the same as the size of the second ambient light transmission region 26b of the polarizing element 26. The shape of the non-diffraction region 51b is not limited to a square, but may be a rectangle, a quadrilateral with rounded corners, a circle, or an ellipse. In particular, when the shape of the non-diffraction region 51b is a quadrilateral with rounded corners, a circle, or an ellipse, unwanted diffraction at the corners of the non-diffraction region can be prevented.

[0031] Figure 8 is a diagram illustrating the function of the polarizing diffraction lens 51. In Figure 8, the first region AR1 shows the first example of operation of the first type polarizing diffraction lens GP1, and the second region AR2 shows the second example of operation of the first type polarizing diffraction lens GP1. In Figure 8, the third region AR3 shows the first example of operation of the second type polarizing diffraction lens GP2, and the fourth region AR4 shows the second example of operation of the second type polarizing diffraction lens GP2. The polarizing diffraction lens 51 shown in Figure 2, etc., is the second type polarizing diffraction lens GP2.

[0032] The polarizing diffraction lens GP1 has the function of converting a collimated second circularly polarized RCP, such as the light ray L1 shown by the solid line on the left side of the drawing, into a first circularly polarized left circularly polarized LCP and focusing it at the focal point FP. When a collimated left circularly polarized LCP, such as the light ray L1 shown by the solid line on the left side of the drawing, is incident, the polarizing diffraction lens GP1 has the function of converting the left circularly polarized LCP into a right circularly polarized RCP and causing it to diverge. Furthermore, when a right circularly polarized RCP diverging from the focal point FP' on the left side of the drawing, such as the light ray L2 shown by the dashed line, is incident, the polarizing diffraction lens GP1 has the function of converting the right circularly polarized RCP into a left circularly polarized LCP and collimating it. In other words, the polarizing diffraction lens GP1 functions like a positive lens of a predetermined focal length for right circularly polarized RCP while reversing the direction of polarization rotation. Also, the polarizing diffraction lens GP1 functions like a negative lens of the same absolute value focal length for left circularly polarized LCP while reversing the direction of polarization rotation. In other words, the polarizing diffraction lens GP1 is an optical element that has positive power for right-circularly polarized RCP and negative power for left-circularly polarized LCP.

[0033] The GP2 polarization diffraction lens has the function of converting a collimated second-circularly polarized light, such as ray L1 shown as a solid line from the left side of the diagram, into a first-circularly polarized light, such as left-circularly polarized light, such as left-circularly polarized light, such as right-circularly polarized light, such as right-circularly polarized light, such as left-circularly polarized light, such as ray L1 shown as a solid line from the left side of the diagram, and also has the function of converting a left-circularly polarized light, such as left-circularly polarized light, such as right-circularly polarized light, such as right-circularly polarized light, such as left

[0034] Polarizing diffraction lenses GP1 and GP2 have a refractive index anisotropy distribution that can be understood in units of numerous annular bands centered on the optical axis AX in a plane. They function as diffraction lenses depending on this refractive index anisotropy distribution and the polarization state of the incident light. Specifically, in polarizing diffraction lenses GP1 and GP2, if the refractive index anisotropy distribution is such that the orientation of the optical axis rotates as it moves away from the optical axis AX in two directions that are perpendicular to and mutually orthogonal to the central optical axis AX (actually repeating in the range of 0 to π), a geometric phase is formed in a specific circularly polarized light incident on it. Diffraction of the circularly polarized light occurs at a diffraction angle that reflects the period length of the rotation of the optical axis in each direction, and the polarization state is reversed. As a whole, the polarizing diffraction lens produces diffraction corresponding to the power formed by the lens shape for a specific circularly polarized light, and reverses the state of the circularly polarized light before and after passing through it, for example from right-hand circular polarization to left-hand circular polarization.

[0035] Although not shown in the diagram, polarizing diffraction lenses GP1 and GP2 are formed by creating a thin film of liquid crystal-containing material on a transparent substrate, and are generally in the form of a thin plate. The liquid crystal-containing material layer contains a predetermined liquid crystal material, and the orientation axes of the liquid crystal molecules are aligned parallel to the X direction, for example, in the region near the optical axis AX, so that the initial geometric phase is formed, and gradually rotate in the XY plane as they move away from the optical axis AX, that is, according to the distance or radius centered on the optical axis AX. In other words, the rotation angle of the orientation axis of the liquid crystal molecules increases with distance from the optical axis AX, and this is repeated periodically. In the liquid crystal compound layer, with respect to the Z direction parallel to the optical axis AX, for example, the orientation axes of the liquid crystal molecules are kept constant and arranged. Note that the direction in which the rotation angle of the orientation axis of the liquid crystal molecules increases is reversed between polarizing diffraction lens GP1 and polarizing diffraction lens GP2. As a method for manufacturing polarizing diffraction lenses GP1 and GP2, for example, a liquid crystal-containing material film, which is a mixture of liquid crystal material and an UV-curable organic material layer, is applied to a substrate, and UV laser light in a predetermined polarization state is scanned two-dimensionally across the liquid crystal-containing material film to adjust the orientation axis of the liquid crystal molecules while curing the organic material layer. This makes it possible to control and fix the orientation axis of the liquid crystal molecules in the liquid crystal-containing material layer in three dimensions, resulting in a liquid crystal compound layer in which the rotation angle of the orientation axis increases as it moves away from the optical axis AX. Such polarizing diffraction lens GP1 itself is a known technology, for example, as a polarization-dependent liquid crystal Fresnel lens (see, for example, Kohei Noda, et al. Applied Optics, February 10 2017, Vol. 56, No. 5: 1302).

[0036] Polarizing diffraction lenses GP1 and GP2 can also be manufactured by the method for manufacturing liquid crystal optical materials described in Japanese Patent Publication No. 2008-501147.

[0037] Polarizing diffraction lenses GP1 and GP2 do not necessarily have to be different; polarizing diffraction lens GP2 can be obtained by rotating polarizing diffraction lens GP1 180° around the Y axis and reversing its front and back sides. In other words, polarizing diffraction lenses GP1 and GP2 can function as both positive and negative lenses for the same circularly polarized light by reversing their front and back sides. This is because, as described above, polarizing diffraction lenses GP1 and GP2 increase the rotation of the orientation axis of the liquid crystal molecules in a specific direction depending on the distance centered on the optical axis AX. Therefore, the direction of rotation with respect to the absolute value of the distance coincides with the direction perpendicular to the optical axis AX, for example, in the ±X direction, and when polarizing diffraction lenses GP1 and GP2 are viewed from the back side, the direction of rotation of the orientation axis is reversed.

[0038] The focal lengths of polarizing diffraction lens GP1 and polarizing diffraction lens GP2 can be increased or decreased depending on the manufacturing method and liquid crystal material. In the liquid crystal compound layer, for example, by increasing the rotation angle of the orientation axis of the liquid crystal molecules as the distance from the optical axis AX increases, and by increasing the rate of increase of the rotation angle with respect to the distance or radius from the optical axis AX, that is, by decreasing the period length of the rotation of the orientation axis, the absolute value of the positive or negative power of polarizing diffraction lenses GP1 and GP2 can be increased, making it possible to adjust the focal length. When passing through polarizing diffraction lenses GP1 and GP2, the loss of circularly polarized light rays L1 is close to zero, and polarizing diffraction lenses GP1 and GP2 exhibit almost 100% transmittance.

[0039] When linearly polarized light is incident on the polarizing diffraction lens GP1, the behavior of the right-circularly polarized RCP and left-circularly polarized LCP contained in the linearly polarized light differs. The right-circularly polarized RCP component is focused after passing through the polarizing diffraction lens GP1, while the left-circularly polarized LCP component diverges after passing through the polarizing diffraction lens GP1, and the rotation direction of each polarization is reversed.

[0040] In the imaging system 50, the polarization diffraction lens 51 is the polarization diffraction lens GP2 shown in Figure 8. When the image light ML incident from the display unit 40 is left-circularly polarized LCP, it functions as an optical element with positive power to the image light ML, reducing the divergence of the image light ML and reversing the direction of polarization rotation to convert it to right-circularly polarized RCP.

[0041] 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.

[0042] 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.

[0043] Figure 9 is a diagram illustrating the state of light in the first display optical system 103a. In Figure 9, the first region BR1 shows the state of the image light ML, and the second region BR2 shows the state of the ambient light OL.

[0044] During image observation, image light ML is emitted from the display area 25a of the image display panel 25. The image light ML emitted from the image display panel 25 includes a first polarization P1 which is vertically polarized and a second polarization P2 which is transversely polarized. The image light ML emitted from the image display panel 25 is incident on the polarizing element 26. The image light ML passes through the polarizer plate 6a in the polarization region 26a of the polarizing element 26 and is restricted to the first polarization P1. After passing through the polarizer plate 6a, the image light ML passes through the quarter-wave plate 6b and is converted from the first polarization P1 to left-circularly polarized LCP. The imaging system 50 becomes positively powered with respect to the left-circularly polarized LCP image light ML, making it possible to observe the image light ML.

[0045] On the other hand, during observation with ambient light, the ambient light OL passes through the first ambient light transmission region 25b of the image display panel 25 and is incident on the polarizing element 26. The ambient light OL passes through the second ambient light transmission region 26b of the polarizing element 26. The ambient light OL that has passed through the second ambient light transmission region 26b passes through the non-diffraction region 51b of the polarizing diffraction lens 51 of the imaging system 50, making it possible to observe the ambient light OL. Even if the ambient light OL passes through the diffraction region 51a, the power to the ambient light OL is approximately zero, and scattered ambient light OL is observed.

[0046] The virtual image display device 100A or display optical system 103a that performs the above-described display enables see-through display by superimposing the image light ML and the ambient light OL.

[0047] In the above explanation, the image display panel 25 was described as having three subpixels of different colors. However, if the chromatic aberration of the imaging system 50 is large, the imager 2a or the image display panel 25 may consist only of single-color pixels.

[0048] Furthermore, a polarizing plate (not shown) that limits the second polarization P2 may be placed on the external side of the image display panel 25. This prevents external light OL from passing through the display area 25a of the image display panel 25 when the image display panel 25 is not emitting light. Alternatively, instead of a polarizing plate, a light-shielding member may be placed on the external side of the image display panel 25 at a position corresponding to the display area 25a to prevent external light OL from passing through the display area 25a of the image display panel 25.

[0049] The virtual image display device 100A, 100B, or optical unit 100 of the first embodiment described above comprises a display 40 that emits circularly polarized image light ML and transmits ambient light OL, and a polarizing diffraction lens 51 having a diffraction region 51a that focuses the image light ML emitted from the display 40 and a non-diffraction region 51b that transmits ambient light OL that passes through the display 40.

[0050] In the above-described virtual image display devices 100A, 100B, or optical unit 100, the polarizing diffracting lens 51 has a positive refractive power with respect to the circularly polarized image light ML from the display 40, so that the image formed by the display 40 can be observed even when the display 40 is placed in front of the eye. Furthermore, because the polarizing diffracting lens 51 has a non-diffracting region 51b, ambient light OL passes through without diffraction, so that ambient light OL can be observed. As a result, the see-through type virtual image display devices 100A, 100B that enable both image observation and ambient light observation can be made thinner.

[0051] [Second Embodiment] The virtual image display device of the second embodiment will now be described. The virtual image display device of the second embodiment is a modified version of the virtual image display device of the first embodiment, and the parts common to the virtual image display device of the first embodiment will not be described.

[0052] In the virtual image display device 100A or optical unit 100 shown in Figure 10, the size of the non-diffraction region 51b of the polarizing diffraction lens 51 is larger than the size of the second external light transmission region 26b of the polarizing element 26. The size of the non-diffraction region 51b is determined by considering the contrast between the external light OL and the image light ML. Specifically, the size of the non-diffraction region 51b is approximately 2 to 500 times the size of the second external light transmission region 26b. This allows the polarizing diffraction lens 51 to efficiently transmit the external light OL captured by the display unit 40.

[0053] The shape of the non-diffraction region 51b is not limited to the square shown in Figure 10; it may also be a rectangle, a quadrilateral with rounded corners, a circle, or an ellipse. Figure 11 shows a modified example of the shape of the non-diffraction region 51b, in which the non-diffraction region 51b has a quadrilateral shape with rounded corners. In other words, the non-diffraction region 51b has an R-shape at the corners of the quadrilateral. This prevents unwanted diffraction at the corners of the non-diffraction region 51b.

[0054] [Third Embodiment] The following describes the virtual image display device of the third embodiment. Note that the virtual image display device of the third embodiment is a modified version of the virtual image display device of the first embodiment, and the parts common to both the first embodiment and the third embodiment will not be described.

[0055] In the virtual image display device 100A or optical unit 100 shown in Figure 12, the polarizing element 126 has a pattern that combines two types of polarizing elements. By passing through the polarizing element 126, the polarization of the image light ML and the polarization of the ambient light OL become different. The polarizing element 126 has a light-transmitting flat plate 126p on which a plurality of first polarizing elements 126a and a plurality of second polarizing elements 126b are arranged in a matrix along the XY plane. In other words, in a plan view, the first polarizing elements 126a and the second polarizing elements 126b are arranged alternately. The first polarizing elements 126a are positioned at a location corresponding to the display area 25a of the image display panel 25. The second polarizing elements 126b are positioned at a location corresponding to the first ambient light transmission area 25b of the image display panel 25.

[0056] The first polarizing element 126a corresponds to the polarization region 26a. The first polarizing element 126a converts the image light ML into linearly polarized light in a predetermined polarization direction, and then into circularly polarized light. The polarization region 26a has, in order from the display unit 40 side, a first polarizing plate 6c and a quarter-wave plate 6b. The first polarizing plate 6c restricts the image light ML to a first polarization P1 in a first polarization direction, specifically, longitudinal polarization or perpendicular polarization. The quarter-wave plate 6b converts the image light ML from linearly polarized light to circularly polarized light.

[0057] The second polarizing element 126b corresponds to the second external light transmission region 26b. The second polarizing element 126b restricts the external light OL to linear polarization with a polarization direction different from that of the image light ML. The second external light transmission region 26b has a second polarizing plate 6d. The second polarizing plate 6d restricts the external light OL to a second polarization P2 with a second polarization direction orthogonal to the first polarization direction, specifically transverse polarization or horizontal polarization.

[0058] In this embodiment, even when the external light OL that has passed through the second polarizing element 126b in the second external light transmission region 26b has linear polarization, the external light OL that passes through the non-diffraction region 51b in the polarizing diffraction lens 51 reaches the eye EY as is. In addition, the external light OL incident on the diffraction region 51a in the polarizing diffraction lens 51 becomes scattered.

[0059] [Fourth Embodiment] The virtual image display device of the fourth embodiment will be described below. The virtual image display device of the fourth embodiment is a modified version of the virtual image display device of the first embodiment, and the parts common to the virtual image display device of the first embodiment will not be described.

[0060] Figure 13 is a conceptual perspective view illustrating the structure of the first display optical system 103a of the first virtual image display device 100A. Figure 14 is a conceptual side cross-sectional view illustrating the structure of the display unit 40.

[0061] The display unit 40 comprises a light source 10 that generates three colors of light in a time-division manner as illumination light, and a composite display member 20 that forms and emits image light ML. The light source 10 is also part of the first display drive unit 102a shown in Figure 1, and is positioned near the upper edge of the light guide member 21, which will be described later, to supply illumination light to the light guide member 21 of the composite display member 20 from its upper edge. The composite display member 20 of the display unit 40 is positioned close to the eye EY with the imaging system 50 in between, enabling observation of a virtual image by 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 system 50 in the direction of the optical axis AX is, for example, about 10 mm to 20 mm. Also, the distance between the transmissive liquid crystal panel 22 of the display unit 40 and the imaging system 50 in the direction of the optical axis AX is, for example, about 5 mm to 25 mm.

[0062] The light source 10 comprises one or more R-emitting elements 10r that generate red light, one or more B-emitting elements 10b that generate blue light, and one or more G-emitting elements 10g that generate green light. The R-emitting elements 10r, B-emitting elements 10b, and G-emitting elements 10g are self-emitting elements, such as organic light-emitting diodes (OLEDs), but may also be light-emitting diodes such as micro-light-emitting diodes (μLEDs) formed from inorganic materials. Between the light source 10 and the light guide member 21 of the composite display member 20, a multiplexer / demultiplexer including a beam splitter can be incorporated to assist in the diffusion of illumination light.

[0063] The composite display member 20 is a plate-shaped member extending along the XY plane perpendicular to the optical axis AX, and comprises, in order from the display unit 40 side, a light guide member 21, a transmissive liquid crystal panel 22, and a polarizing element 226. The composite display member 20 has a structure in which the light guide member 21, the transmissive liquid crystal panel 22, and the polarizing element 226 are stacked and integrated by a frame (not shown). Here, the light guide member 21 and the transmissive liquid crystal panel 22 are arranged in close proximity, at a predetermined interval or less. The transmissive liquid crystal panel 22 is an imager 2a that forms the image light ML. The transmissive liquid crystal panel 22 is a display member 2b and includes a plurality of pixels PX (see Figure 14) arranged in a matrix along the XY plane.

[0064] Furthermore, an outer polarizer 27 (see Figure 14) is provided on the external side of the light guide member 21 to limit the polarization of the external light OL. The outer polarizer 27 limits the external light OL to a second polarization P2 (see Figure 15), which is linearly polarized in a predetermined polarization direction, for example, transverse or horizontal polarization.

[0065] The light source 10 and the light guide member 21 function as a backlight LL. In this embodiment, the backlight LL, the transmissive liquid crystal panel 22, and the polarizing element 226 function as a light separation member 41 that separates the image light ML and the ambient light OL into different light components.

[0066] The imaging system 50 is positioned on the face side, or -Z side, relative to the display unit 40 or composite display member 20, and covers the area in front of the eyes. The imaging system 50 includes a polarizing diffracting lens 51.

[0067] Referring to Figure 14, the light source 10 generates three colors of illumination light ILr, ILg, and ILb from the light-emitting elements 10r, 10g, and 10b as illumination light IL, and supplies the three colors of illumination light ILr, ILg, and ILb to the light guide member 21 of the composite display member 20.

[0068] The light guide member 21 has a ferroelectric liquid crystal plate 12 fixed to the light guide plate 11. Illumination light ILr, ILg, and ILb from the light source 10 are coupled into the light guide plate 11 from its upper end. The light guide plate 11 propagates the illumination light ILr, ILg, and ILb incident from the light source 10 downwards.

[0069] The ferroelectric liquid crystal plate 12 is a device that performs switch-type operation in response to a drive signal from the drive circuit 81 shown in Figure 13, and can switch between a scattering state (on state) in which illumination light IL (ILr, ILg, ILb) is emitted outside the light guide plate 11 and a transparent state (off state) in which ambient light OL is transmitted and allowed to pass through. The ferroelectric liquid crystal plate 12 comprises a ferroelectric liquid crystal layer 12a sandwiched between a pair of substrates 12b and 12c via a transparent electrode layer (not shown). The ferroelectric liquid crystal layer 12a is, for example, a reverse-mode polymer dispersion liquid crystal, which is in a transmitting state when no electric field is applied and in a scattering state when an electric field is applied (see, for example, Japanese Patent Application Publication No. 6-308543). The ferroelectric liquid crystal plate 12 can be switched on and off on a whole-surface basis, not on a pixel PX basis. The ferroelectric liquid crystal layer 12a may be in a transmitting state when an electric field is applied and in a scattering state when no electric field is applied.

[0070] The transmissive liquid crystal panel 22 includes a liquid crystal modulation member 14 and a pair of polarizing members 15 and 16 that sandwich the liquid crystal modulation member 14. In this case, the transmissive liquid crystal panel 22 is a modulation element made of, for example, an IPS (in-plane switching) type liquid crystal, and has image light generating pixels PXc and ambient light transmitting pixels PXt. That is, in the transmissive liquid crystal panel 22, a plurality of image light generating pixels PXc and a plurality of ambient light transmitting pixels PXt are arranged in a matrix along the XY plane. In other words, in a planar view, the image light generating pixels PXc and ambient light transmitting pixels PXt are arranged alternately. The image light generating pixels PXc correspond to the display area 25a, and the ambient light transmitting pixels PXt correspond to the first ambient light transmission area 25b.

[0071] The liquid crystal modulation member 14 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. The incident polarizing member 15 restricts the image light ML and the ambient light OL to a linear polarization with a predetermined polarization direction, for example, a second polarization P2 (see Figure 15) which is transverse or horizontal polarization. The exit polarizing member 16 is a light-transmitting flat plate 16p, with a polarizing plate 6e at a position corresponding to the image light generation pixel PXc and a wave plate 6f at a position corresponding to the ambient light transmission pixel PXt. In other words, on the flat plate 16p, a plurality of polarizing plates 6e and a plurality of wave plates 6f are arranged in a matrix along the XY plane. In other words, in a plan view, the polarizing plates 6e and wave plates 6f are arranged alternately. The polarizing plate 6e restricts the polarization to a linear polarization rotated by 90° with respect to the polarization direction restricted by the incident polarizing member 15, specifically, a first polarization P1 (see Figure 15) which is longitudinal or perpendicular polarization. The waveplate 6f converts the linear polarization of the ambient light OL emitted from the incident polarizing member 15 into a linear polarization P3 (see Figure 15) that is different from the polarization direction restricted by the incident polarizing member 15 and the polarizer 6e. The waveplate 6f aligns the linear polarization axis of the ambient light OL with the axis of the quarter-waveplate 6b of the polarizing element 226.

[0072] The transmissive liquid crystal panel 22 can be switched on and off in pixel units PX in response to a drive signal from the drive circuit 81, and incident light can be partially passed through at any intermediate grayscale between on and off. For this reason, the liquid crystal modulation member 14 includes not only the liquid crystal layer 31, common electrode 32, pixel electrode 33, and black matrix 35, but also scan lines, signal lines, switch elements, etc., although these are not shown in the figure.

[0073] Furthermore, the transmissive liquid crystal panel 22 or the liquid crystal modulation member 14 may rotate the polarization direction of the incident light when no electric field is applied, but not when an electric field is applied.

[0074] The polarizing element 226 is entirely a quarter-wave plate 6b. The quarter-wave plate 6b is configured as a polarization region 226a, and in combination with the polarizing plate 6e, it converts linearly polarized image light ML into circularly polarized light. Furthermore, the quarter-wave plate 6b is configured as a second external light transmission region 226b, and in combination with the wave plate 6f, it emits linearly polarized ambient light OL.

[0075] Furthermore, in the combination of the polarizing element 226 and the polarizing member 16 of the transmissive liquid crystal panel 22, the region through which the image light ML passes can be considered as the polarized region 226a, and the region through which the ambient light OL passes can be considered as the second ambient light transmission region 226b.

[0076] In this embodiment, the polarizing element 226 may be a light-transmitting flat plate in which a plurality of quarter-wave plates 6b are arranged in a matrix along the XY plane, with the polarizing region 226a being a light-transmitting flat plate. In this case, the second external light-transmitting region 226b of the polarizing element 226 is an unpolarized region that transmits external light OL as is, and is, for example, the light-transmitting flat plate itself, or an aperture formed in the flat plate.

[0077] Figure 15 is a diagram illustrating the state of light in the first display optical system 103a. In Figure 15, the first region CR1 shows the case when the first display optical system 103a is in the image observation period and the display unit 40 is in the display state. The second region CR2 shows the case when the first display optical system 103a is in the ambient light observation period and the display unit 40 is in the non-display state.

[0078] During the video observation period, when the display unit 40 is in the display state, the light-emitting elements 10r, 10g, and 10b of the light source 10 emit light, and illumination light ILr, ILg, and ILb are supplied to the light guide member 21 (see Figure 14). At this timing, when the ferroelectric liquid crystal plate 12 is switched to the first state, the ON state, and enters the scattering state, the illumination light ILr, ILg, and ILb illuminate the liquid crystal modulation member 14 as a second polarization P2, which is transversely polarized or horizontally polarized, via the polarizing member 15 of the transmissive liquid crystal panel 22. In other words, the video light generating pixels PXc that constitute the transmissive liquid crystal panel 22 are illuminated. The video light MLr, MLg, and MLb (see Figure 14) that have passed through the liquid crystal modulation member 14 have their polarization planes rotated according to the drive signal, and only the first polarization P1, which is vertically polarized or perpendicularly polarized, is emitted after passing through the polarizing member 16. The image light MLr, MLg, and MLb emitted from the image light generating pixel PXc of the transmissive liquid crystal panel 22 are converted from first polarization P1 to left circular polarization LCP via the quarter-wave plate 6b of the polarization region 226a of the polarizing element 226.

[0079] On the other hand, when the display 40 is not displayed during the ambient light observation period, the light source 10 is set to a non-emitting state, i.e., off state, and the supply of illumination light IL to the light guide member 21 is stopped. At this timing, when the ferroelectric liquid crystal plate 12 is switched to the second state, the off state, and becomes a transmitting state, the ambient light OL travels in a straight line so as to cross the light guide member 21 and is incident on the transmissive liquid crystal panel 22. At this time, the ambient light transmitting pixels PXt of the transmissive liquid crystal panel 22 are, for example, normally off and are set to the maximum transmitting state by a drive signal, and the second polarized P2 of the ambient light OL incident on the ambient light transmitting pixels PXt of the transmissive liquid crystal panel 22 becomes linearly polarized P3 with a predetermined polarization direction by the polarizing member 16. The linearly polarized ambient light OL OL is emitted by traveling in a straight line through the transmissive liquid crystal panel 22, i.e., the ambient light transmitting pixels PXt. The ambient light OL emitted from the ambient light-transmitting pixel PXt of the transmissive liquid crystal panel 22 passes through the second ambient light-transmitting region 226b of the polarizing element 226 while remaining linearly polarized P3.

[0080] During the image observation period, the imaging system 50 has positive power, making it possible to observe the image light ML. During the ambient light observation period, the power of the imaging system 50 is approximately zero, making it possible to observe the ambient light OL.

[0081] Figure 16 is a timing chart illustrating the display operation by the display optical system 103a. The horizontal axis represents time, and from top to bottom, it shows the blinking signal SS1 of the R light-emitting element 10r, the R drive signal SM1 (indicated in red) applied to the liquid crystal modulation member 14, the blinking signal SS2 of the G light-emitting element 10g, the G drive signal SM2 (indicated in green) applied to the liquid crystal modulation member 14, the blinking signal SS3 of the B light-emitting element 10b, the B drive signal SM3 (indicated in blue) applied to the liquid crystal modulation member 14, and the on / off signal SD of the ferroelectric liquid crystal plate (FLC) 12. The operation of the first virtual image display device 100A includes a first subframe Z1, which is a subframe for image observation, and a second subframe Z2, which is a subframe for ambient light observation, in each frame.

[0082] In this case, when the first virtual image display device 100A is in the image observation period and the transmissive liquid crystal panel 22 is in the display state, the three colors of image light MLr, MLg, and MLb are displayed in time division. When the first virtual image display device 100A is in the ambient light observation period and the transmissive liquid crystal panel 22 is in the non-display state, the ambient light OL passes through the ambient light transmitting pixel PXt of the transmissive liquid crystal panel 22.

[0083] In the above explanation, a display unit 40 incorporating a transmissive liquid crystal panel 22 was used, but other types of imagers 2a, such as an organic electroluminescent (OLED) display, can also be used instead of the transmissive liquid crystal panel 22. However, it is desirable that the imager 2a of the OLED display blocks ambient light OL while displaying an image and transmits ambient light OL when the image display is stopped. In this case, it is desirable to place a polarizing plate on the light-emitting side of the OLED display as the imager 2a.

[0084] Furthermore, as shown in Figure 17, in this embodiment, instead of providing the ferroelectric liquid crystal plate 12 shown in Figure 14, a scattering member 11a that scatters illumination light IL may be provided on the ejection side of the light guide plate 11 at a position corresponding to the display area 25a.

[0085] [Variations and other variations] Although the present invention has been described in reference to the embodiments described above, the present invention is not limited to the embodiments described above, and can be implemented in various forms without departing from the spirit thereof, for example, the following modifications are also possible.

[0086] The display unit 40 and the composite display component 20 incorporated therein are not limited to those exemplified in Figure 3, etc., but can employ various types of display panels.

[0087] In the display component 2b (image display panel 25 or transmissive liquid crystal panel 22), the number, size, arrangement, etc., of the display area 25a and the first external light transmission area 25b can be changed as appropriate.

[0088] In the polarizing elements 26,126,226, the number, size, and arrangement of the polarization regions 26a,226a and the second external light transmission regions 26b,226b can be changed as appropriate.

[0089] In the polarizing diffraction lens 51, the number, size, and arrangement of the diffracted regions 51a and non-diffracted regions 51b can be changed as appropriate.

[0090] In the imaging system 50, the polarization diffraction lens 51 may be the polarization diffraction lens GP1 shown in Figure 8. In this case, the display unit 40 is configured such that the image light ML and the ambient light OL incident on the quarter-wave plate 6b become the second polarization P2 and the first polarization P1, respectively. When the image light ML incident from the display unit 40 is right-circularly polarized RCP, the polarization diffraction lens GP1 functions as an optical element with positive power to the image light ML, reducing the divergence of the image light ML and reversing the direction of polarization rotation to make it left-circularly polarized LCP. When the ambient light OL is left-circularly polarized LCP, the polarization diffraction lens GP1 functions as an optical element with negative power to the ambient light OL, reducing the degree of convergence of the ambient light OL and reversing the direction of polarization rotation to make it right-circularly polarized RCP.

[0091] The above explanation assumes that the HMD200 is worn on the head; however, the virtual image display devices 100A and 100B can also be used as handheld displays that are looked through like binoculars, without being worn on the head. In other words, in this invention, a head-mounted display includes a handheld display.

[0092] [Summary of this disclosure] A summary of this disclosure is provided below.

[0093] (Note 1) A display that emits circularly polarized light and transmits ambient light, A polarizing diffractive lens having a diffractive region for focusing the image light emitted from the display and a non-diffractive region for transmitting the external light that passes through the display, Equipped with, Virtual image display device. In the above-described virtual image display device, the polarizing diffracting lens has a positive refractive power for circularly polarized image light from the display, allowing the image formed by the display to be observed even when the display is placed directly in front of the eye. Furthermore, because the polarizing diffracting lens has a non-diffracting region, ambient light passes through without diffraction, allowing the ambient light to be observed. As a result, a see-through type virtual image display device that enables both image observation and ambient light observation can be made thinner.

[0094] (Note 2) In a plan view, the polarizing diffracting lens has multiple non-diffracting regions arranged in an island-like manner, and the diffracting regions are arranged in the remaining region. The virtual image display device described in Appendix 1. As a result, ambient light that has passed through the island-like arrangement of non-diffractive regions reaches the eye without being diffracted.

[0095] (Note 3) The display unit has a display member and a polarizing element as an optical separation member for separating the image light and the ambient light. The display member has a display area that emits the image light and a first external light transmitting area that transmits the external light. The polarizing element has a polarization region that converts the image light emitted from the display area into circularly polarized light, and a second external light transmitting region that transmits external light. A virtual image display device as described in either Appendix 1 or 2. The image light becomes circularly polarized by passing through the display area of ​​the display component and the polarization area of ​​the polarizing element. Furthermore, the ambient light becomes a different light component from the image light by passing through the first ambient light transmission area of ​​the display component and the second ambient light transmission area of ​​the polarizing element.

[0096] (Note 4) In the display member, a plurality of the display areas and a plurality of the first external light transmitting areas are arranged. In the polarizing element, a plurality of polarization regions are arranged at positions corresponding to the display region, and a plurality of second ambient light transmission regions are arranged at positions corresponding to the first ambient light transmission region. The virtual image display device described in Appendix 3.

[0097] (Note 5) The non-diffractive region is larger than the second external light transmission region. A virtual image display device as described in either Appendix 3 or 4. This allows the polarizing diffraction lens to efficiently transmit the ambient light captured by the display.

[0098] (Note 6) The non-diffraction region has one of the following shapes: a square, a square with rounded corners, a circle, or an ellipse. A virtual image display device as described in any one of the appendices 1 to 5. In particular, when the shape of the non-diffraction region is a square, circle, or ellipse with rounded corners, unwanted diffraction at the corners of the non-diffraction region can be prevented.

[0099] (Note 7) The polarization region comprises, in order from the display side, a polarizing plate that restricts the image light to a predetermined linear polarization, and a quarter-wave plate that converts the predetermined linear polarization to a predetermined circular polarization. A virtual image display device as described in any one of the appendices 3 to 6. This allows the image light emitted from the display to be circularly polarized.

[0100] (Note 8) The display member is an image display panel having a light-emitting region that forms the image light as the display area. A virtual image display device as described in any one of the appendices 3 to 7.

[0101] (Note 9) The display member comprises a backlight and a liquid crystal panel. The liquid crystal panel has image light generation pixels as the display area and external light transmission pixels as the first external light transmission area. A virtual image display device as described in any one of the appendices 3 to 7.

[0102] (Note 10) A display that emits circularly polarized light and transmits ambient light, A polarizing diffractive lens having a diffractive region for focusing the image light emitted from the display and a non-diffractive region for transmitting the external light that passes through the display, Equipped with, Optical unit. [Explanation of Symbols]

[0103] 2a...Imager, 2b...Display component, 5a...Emitting region, 6a,6c,6d,6e...Polarizing plate, 6b...Quarter wave plate, 6f...Wave plate, 10...Light source, 11...Light guide plate, 11a...Scattering component, 12...Ferroelectric liquid crystal plate, 14...Liquid crystal modulation component, 15,16...Polarizing component, 20...Composite display component, 21...Light guide component, 22...Transmissive liquid crystal panel, 25...Image display panel, 25a...Display region, 25b...First external light transmission region, 26...Polarizing element, 26a...Polarization region, 26b...Second external light transmission region, 27...Outer polarizing plate, 40...Display unit, 41...Light separation component, 50...Imaging system, 51...Polarizing diffraction lens, 51a...Diffraction region, 51b...Non-diffraction region, 80...Control device, 81...Drive circuit, 90...User terminal, 100...Optical unit, 100A,100B...Virtual image display device, 102...Drive device, 103a,103b...Display optical system, 126...Polarizing element, 126a...First polarizing element, 126b...Second polarizing element, 200...Head-mounted display device, 226...Polarizing element, 226a...Polarization region, 226b...Second external light transmission region, AX...Optical axis, EY...Eye, GP1,GP2...Polarization diffraction lens, IL...Illumination light, LL...Backlight, ML...Image light, OL...External light, PXc...Image light generating pixel, PXt...External light transmission pixel, US...Wearer

Claims

1. A display that emits circularly polarized light and transmits ambient light, A polarizing diffractive lens having a diffractive region for focusing the image light emitted from the display and a non-diffractive region for transmitting the external light that passes through the display, Equipped with, Virtual image display device.

2. In a plan view, the polarizing diffracting lens has multiple non-diffracting regions arranged in an island-like manner, and the diffracting regions are arranged in the remaining region. The virtual image display device according to claim 1.

3. The display unit has a display member and a polarizing element as an optical separation member for separating the image light and the ambient light. The display member has a display area that emits the image light and a first external light transmitting area that transmits the external light. The polarizing element has a polarization region that converts the image light emitted from the display area into circularly polarized light, and a second external light transmitting region that transmits external light. The virtual image display device according to claim 1.

4. In the display member, a plurality of the display areas and a plurality of the first external light transmitting areas are arranged. In the polarizing element, a plurality of polarization regions are arranged at positions corresponding to the display region, and a plurality of second external light transmission regions are arranged at positions corresponding to the first external light transmission region. The virtual image display device according to claim 3.

5. The non-diffractive region is larger than the second external light transmission region. The virtual image display device according to claim 3.

6. The non-diffraction region has one of the following shapes: a square, a square with rounded corners, a circle, or an ellipse. The virtual image display device according to claim 1.

7. The polarization region comprises, in order from the display side, a polarizing plate that restricts the image light to a predetermined linear polarization, and a quarter-wave plate that converts the predetermined linear polarization to a predetermined circular polarization. The virtual image display device according to claim 3.

8. The display member is an image display panel having a light-emitting region that forms the image light as the display area. The virtual image display device according to claim 3.

9. The display member comprises a backlight and a liquid crystal panel. The liquid crystal panel has image light generation pixels as the display area and external light transmission pixels as the first external light transmission area. The virtual image display device according to claim 3.

10. A display that emits circularly polarized light and transmits ambient light, A polarizing diffractive lens having a diffractive region for focusing the image light emitted from the display and a non-diffractive region for transmitting the external light that passes through the display, Equipped with, Optical unit.

Images