Virtual image display device and optical unit

Abstract

To improve video quality. [Solution] The virtual image display device 100A comprises a display unit 10 that emits circularly polarized image light ML, and an optical member 20 that folds the image light ML twice by reflection to form a virtual image. The optical member 20 comprises a lens member 21, a transmissive reflective optical element 22 provided opposite to a first optical surface 21a of the lens member 21 that is close to the display unit 10, a reflective polarizing optical element 25 provided opposite to a second optical surface 21b of the lens member 21 that is far from the display unit 10 and reflects the image light ML which is linearly polarized in a first polarization direction, and a waveplate element 24 provided between the reflective optical element 22 and the polarizing optical element 25, made of a photocrosslinkable polymer liquid crystal material CS, which makes the image light ML that has passed through the reflective optical element 22 linearly polarized in a first polarization direction, and makes the image light ML that has been reflected by the reflective optical element 22 and returns linearly polarized in a second polarization direction. The waveplate element 24 has an orientation of d ± 5° or less with respect to the gradient normal angle d of the optical surface on which the waveplate element 24 is provided.

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.

Background Art

[0002] As a pancake lens, in order to suppress ghosts during video viewing, a front optical element and a rear optical element that constitute an optical component are integrally adhered and are known (Patent Document 1). In the pancake lens of Patent Document 1, a hybrid film that functions as a polarizer and a quarter-wave plate is attached to a cylindrical surface in the vertical direction between the front optical element and the rear optical element.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the pancake lens of the above Patent Document 1, the incident angle of the light beam incident on the hybrid film varies depending on cross-sections in different directions, specifically, a cylindrical curved surface and a cylindrical plane. Therefore, due to the viewing angle characteristics of the hybrid film, there is a possibility that quality deterioration may occur in the displayed video.

Means for Solving the Problems

[0005] A virtual image display device in one aspect of the present invention comprises a display that emits circularly polarized image light, and an optical member that forms a virtual image by reflecting the image light twice. The optical member comprises a lens member having one or more lenses, a transmissive reflective optical element provided opposite a first optical surface of the lens member that is close to the display, a reflective polarizing optical element provided opposite a second optical surface of the lens member that is far from the display and reflects image light that is linearly polarized in a first polarization direction, and a waveplate element provided between the reflective optical element and the polarizing optical element, made of a photocrosslinkable polymer liquid crystal material, which polarizes the image light that has passed through the reflective optical element into linearly polarized light in a first polarization direction, and the image light that is reflected by the reflective optical element and returns into linearly polarized light in a second polarization direction. The waveplate element has an orientation of d ± 5° or less with respect to the gradient normal angle d of the optical surface on which the waveplate element is provided.

[0006] An optical unit in one aspect of the present invention comprises a display that emits circularly polarized image light, and an optical member that refracts the image light twice to form a virtual image, wherein the optical member includes a lens member having one or more lenses, a transmissive reflective optical element provided opposite a first optical surface of the lens member that is close to the display, a reflective polarizing optical element provided opposite a second optical surface of the lens member that is far from the display and reflects image light that is linearly polarized in a first polarization direction, and a waveplate element provided between the reflective optical element and the polarizing optical element, made of a photocrosslinkable polymer liquid crystal material, which polarizes the image light that has passed through the reflective optical element into linearly polarized light in a first polarization direction, and the image light that is reflected by the reflective optical element and returns into linearly polarized light in a second polarization direction, wherein the waveplate element has an orientation of d ± 5° or less with respect to the gradient normal angle d of the optical surface on which the waveplate element is provided. [Brief explanation of the drawing]

[0007] [Figure 1] This is an external perspective view illustrating the mounting state of the virtual image display device according to the first embodiment. [Figure 2] This is a lateral cross-sectional view illustrating the optical structure of the display optical system. [Figure 3] This is a diagram illustrating an exposure apparatus. [Figure 4]This is a diagram illustrating spherical wave lithography. [Figure 5] This is a conceptual diagram illustrating the optical operation of a virtual image display device. [Figure 6] This diagram illustrates the setting conditions for the virtual image display device. [Figure 7] This is a diagram illustrating plane wave lithography. [Figure 8] This graph illustrates the incident ray angle in a waveplate element used in plane wave lithography. [Figure 9] This graph illustrates the typical viewing angle characteristics of waveplate elements. [Figure 10] This graph illustrates the angle of incident light on a waveplate element used in spherical wave lithography. [Figure 11] This graph shows the relationship between the F-number and the ratio of the radius of curvature. [Figure 12] This graph shows the angle of light incidence on the waveplate elements of the examples and comparative examples. [Figure 13] This graph shows the brightness unevenness, color unevenness, and ghosting of the waveplate elements in the examples and comparative examples. [Figure 14] This diagram illustrates the verification of the viewing angle characteristics of a waveplate element. [Figure 15] This is a side cross-sectional view illustrating the optical structure of the display optical system of the second embodiment. [Figure 16] This is a lateral cross-sectional view illustrating the optical structure of the display optical system in a modified example. [Figure 17] This diagram illustrates the fabrication of a modified waveplate element. [Modes for carrying out the invention]

[0008] [First Embodiment] The following describes a virtual image display device, etc., according to the first embodiment of the present invention, with reference to Figure 1 and other figures.

[0009] FIG. 1 is a perspective view for explaining the wearing state of a head-mounted display, that is, a head-mounted display device 200. The head-mounted display device (hereinafter also referred to as HMD) 200 allows an observer or wearer US wearing the same to recognize an image as a virtual image. In FIG. 1 and the like, X, Y, and Z are a rectangular coordinate system. The +X direction corresponds to the horizontal direction in which both eyes EY of the observer or wearer US wearing the HMD 200 are aligned. The +Y direction corresponds to the upward direction orthogonal to the horizontal direction in which both eyes EY of the wearer US are aligned. The +Z direction corresponds to the forward direction or the front direction of the wearer US. The ±Y direction is parallel to the vertical axis or the vertical direction.

[0010] 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 that is an information terminal. The first virtual image display device 100A includes a first display driving unit 102a disposed at the upper part and a first display optical system 103a that covers in front of the eyes. The second virtual image display device 100B includes a second display driving unit 102b disposed at the upper part and a second display optical system 103b that covers in front of the eyes. 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 support the 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. The combination of the pair of display driving units 102a and 102b is called a driving device 102.

[0011] FIG. 2 is a conceptual side view for explaining the structure of the first display optical system 103a. The first display optical system 103a includes a display 10 that emits circularly polarized video light ML, an optical member 20 that reflects the video light ML twice by reflection to form a virtual image, and a circuit member 80 that controls operations of the display 10 and the like.

[0012] In the first virtual image display device 100A, the optical device (specifically, the display 10 and the optical member 20) excluding the circuit member 80 is called an optical unit 100.

[0013] Although detailed description will be omitted, the second virtual image display device 100B or the second display optical system 103b is optically identical to the first virtual image display device 100A or the first display optical system 103a, or is a left-right reversed version of the first virtual image display device 100A or the first display optical system 103a. Hereinafter, the first virtual image display device 100A or the first display optical system 103a will be described, and the description of the second virtual image display device 100B or the second display optical system 103b will be omitted.

[0014] In the case of the illustrated first display optical system 103a, it achieves a FOV of around 100°, specifically, a FOV of 120°, and the thickness from the display 10 to the rear end emission surface 21c of the outer edge of the optical member 20 is about 10 mm to 15 mm.

[0015] In the first display optical system 103a, the display 10 includes an image display panel 11 which is a self-emitting type image light generation device, and a first polarization control member PC1 that makes the video light ML emitted from the image display panel 11 into circularly polarized light.

[0016] The image display panel 11 is, for example, an OLED (Organic Light Emitting Diode) display, and forms a monochrome or color still image or moving image on the two-dimensional display surface 11d. The video light ML emitted from the image display panel 11 includes random polarization. The image display panel 11 is driven by the circuit member 80 to perform a display operation. The image display panel 11 is not limited to an OLED display and can be replaced with a display device using a micro OLED, organic EL (Organic Electro-Luminescence), inorganic EL, LED, micro LED, LED array, laser array, quantum dot light-emitting element, etc.

[0017] The image display panel 11 is not limited to a self-emissive image light generation device, but may also be composed of an LCD or other light modulation element, and an image may be formed by illuminating the light modulation element with a light source such as a background. Instead of an LCD, an LCOS (Liquid crystal on silicon, LCoS is a registered trademark), a digital micromirror device (specifically DLP: registered trademark), a laser beam scan, etc., can also be used as the image display panel 11.

[0018] The first polarization control member PC1 has a linear polarizer 14 and a quarter-wave plate 15, in that order from the image display panel 11 side. If the image display panel 11 is an OLED, the first polarization control member PC1 may be a circular polarizer 16 formed by bonding the linear polarizer 14 and the quarter-wave plate 15 together.

[0019] The linear polarizer 14 is, for example, an absorption-type polarizer, and in this embodiment, it selectively allows only the second linearly polarized light (vertical polarized light) in the Y direction, which is perpendicular to the image, to pass through. In other words, of the image light ML emitted from the image display panel 11, only the linearly polarized light in the Y direction passes through the linear polarizer 14 and is incident on the quarter-wave plate 15. The linear polarizer 14 is in the form of a sheet and is made by stretching a film impregnated with a dichroic dye such as iodine in a certain direction.

[0020] The quarter-wave plate 15 has its principal axis or velocity axis set between the vertical and horizontal directions, that is, between the Y direction and the X direction, and converts the second linearly polarized light (vertically polarized light) that has passed through the linear polarizer 14 into, for example, right-circularly polarized light C1. The quarter-wave plate 15 is formed from a liquid crystal material such as a photocrosslinkable polymer liquid crystal material, but it may also be made from a birefringent crystalline material such as quartz processed into a thin plate. As a specific manufacturing method, the linear polarizer 14 is placed on the cover glass 11c of the image display panel 11, and the quarter-wave plate 15 made of an ultraviolet-curable photocrosslinkable polymer liquid crystal material is placed on top of it. The photocrosslinkable polymer liquid crystal material is coated onto the cover glass 11c while controlling the film thickness by spin coating, inkjet, etc., and then irradiated with polarized ultraviolet or ultraviolet light, and then baked to function as a quarter-wave plate 15.

[0021] The optical component 20 comprises, in order from the image display panel 11 side, a reflective optical element 22, a lens member 21, and a second polarization control member PC2. In the optical component 20, the second polarization control member PC2 has, in order from the image display panel 11 side, a waveplate element 24 and a reflective polarizing optical element 25. That is, the waveplate element 24 is provided between the second optical surface 21b of the lens member 21 and the polarizing optical element 25.

[0022] In this embodiment, the lens element 21 constituting the imaging optical element 20 has only one lens element, resulting in an optically very simple configuration. Furthermore, because it can be constructed with just one lens element, the number of parts is simply reduced, and the process of bonding lenses together is unnecessary, thus reducing costs. As a result, the overall weight of the optical system can be made very light.

[0023] The lens member 21 is a convex-concave or meniscus lens having positive power, and has a first optical surface 21a on the incident side and a second optical surface 21b on the exit side. The first optical surface 21a and the second optical surface 21b are curved surfaces, specifically spherical or aspherical surfaces.

[0024] The first optical surface 21a is convex, and the second optical surface 21b is concave. When the first optical surface 21a is convex, the reflective optical element 22 can be given positive power, making it easier to miniaturize the first virtual image display device 100A by narrowing the distance between the display unit 10 and the optical member 20. When the second optical surface 21b is concave, the ray angle of the image light ML emitted from the image display panel 11 can be tilted inward, i.e., towards the optical axis AX, which can reduce the refraction of the principal ray at the second optical surface 21b of the lens member 21 overall, making it easier to reduce aberrations of the optical member 20.

[0025] The lens member 21 is the outer edge of the optical member 20 and has an annular first end face 21d extending radially perpendicular to the optical axis AX and parallel or substantially parallel to the Y direction from the edge of the second optical surface 21b. The lens member 21 is also the outer edge of the optical member 20 and has a cylindrical second end face 21e extending parallel or substantially parallel to the Z direction from the edge of the first optical surface 21a. The first end face 21d and the second end face 21e are orthogonal to each other. The first and second end faces 21d and 21e function as positioning parts PS or positioning surfaces for positioning relative to a case (not shown), for example. The first end face 21d is not provided with the second polarization control member PC2, i.e., the waveplate element 24 and the polarizing optical element 25, and its surface is exposed. The first end face 21e is not provided with the reflective optical element 22 and its surface is exposed. This prevents, for example, the reflection of unnecessary image light ML.

[0026] The lens component 21 is formed from, for example, resin, but it can also be made of glass. Using glass for the lens component 21 is advantageous from the standpoint of miniaturization.

[0027] The reflective optical element 22 is provided opposite the first optical surface 21a. That is, the first optical surface 21a and the reflective optical element 22 have the same shape, but the first optical surface 21a functions as a convex refractive surface, and the reflective optical element 22 functions as a concave reflective surface. On the other hand, the polarizing optical element 25 is provided opposite the second optical surface 21b, and more specifically, it is formed on the second optical surface 21b via a thin film waveplate element 24. That is, the second optical surface 21b and the polarizing optical element 25 have the same shape, but the second optical surface 21b functions as a concave refractive surface, and the polarizing optical element 25 functions as a convex reflective surface.

[0028] The reflective optical element 22 is a transmissive half-mirror HM that partially transmits and partially reflects the image light ML. The reflective optical element 22 covers the pupil position PP where the eye EY or pupil is located and has a concave shape toward the pupil position PP and a convex shape toward the outside world. The reflectance of the reflective optical element 22 with respect to the image light ML is set to approximately 50%, for example, from the viewpoint of ensuring the brightness of the image light ML, but is not limited to this. The reflective optical element 22 is a single-layer or multi-layer film of a metal such as Al or Ag with adjusted film thickness. The reflective optical element 22 can be formed, for example, by lamination using vapor deposition, but it can also be formed by attaching a sheet-like reflective film.

[0029] The waveplate element 24 has its principal axis or velocity axis set between the vertical and horizontal directions, that is, between the Y direction and the X direction, and corresponds to a quarter waveplate. The waveplate element 24 has a phase state of 1 / 4 wavelength across its entire surface. In other words, the waveplate element 24 converts circularly polarized light, for example right-circularly polarized light C1, that has passed through the lens member 21 into first linearly polarized light (horizontal polarized light) L1 in a first polarization direction corresponding to the horizontal X direction. The waveplate element 24 also converts the first linearly polarized light L1 reflected by the polarizing optical element 25 into left-circularly polarized light C2. Furthermore, the waveplate element 24 converts left-circularly polarized light C2, which has passed through the waveplate element 24 twice, through the lens member 21 and reflected again by the reflective optical element 22, into second linearly polarized light (vertical polarized light) L2 in a second polarization direction corresponding to the vertical or vertical Y direction. The waveplate element 24 is formed of a liquid crystal material, such as a photocrosslinkable polymer liquid crystal material. The waveplate element 24 is a thin-film waveplate formed on the second optical surface 21b, and is specifically formed from an ultraviolet-curable, photocrosslinkable polymer liquid crystal material.

[0030] The fabrication of the waveplate element 24 will now be described. Figure 3 is a diagram illustrating the exposure apparatus 50. Figure 4 is a diagram illustrating spherical wave exposure. As shown in Figure 3, the photocrosslinkable polymer liquid crystal material CS that forms the waveplate element 24 is exposed using the exposure apparatus 50. The exposure light 9c from the exposure apparatus 50 forms the orientation of the waveplate element 24. The photocrosslinkable polymer liquid crystal material CS is coated onto the second optical surface 21b of the lens member 21 to form a photocrosslinkable polymer liquid crystal material layer, i.e., a thin film. Polarized UV 9b, which is linearly polarized ultraviolet light with a controlled polarization direction, is irradiated onto this thin film of photocrosslinkable polymer liquid crystal material CS. In this embodiment, spherical wave exposure is performed on the lens member 21 coated with the photocrosslinkable polymer liquid crystal material CS. This makes it possible to control the orientation state of rod-shaped molecular species (i.e., molecules with refractive index differences between the major and minor axes) that exhibit liquid crystallinity while curing the thin film of photocrosslinkable polymer liquid crystal material CS. In this process, among the molecular species that exhibit liquid crystalline properties in response to ultraviolet light, those that extend in a direction consistent with the polarization direction of the ultraviolet light cross-link, and their orientation is fixed in the same direction as the polarization direction.

[0031] As shown in Figure 3, the exposure apparatus 50 includes a UV laser light source 51, a diffusion lens 52, a collimating lens 53, a linear polarizing plate 54, and a spherical wave forming lens 55. The spherical wave forming lens 55 adjusts the exposure light 9c to a desired spherical wave and is provided on the emission side of the linear polarizing plate 54. The lens member 21 is installed with the second optical surface 21b, coated with a photocrosslinkable polymer liquid crystal material CS, facing the exposure side. The diffusion lens 52 diffuses the ultraviolet light 9a emitted from the UV laser light source 51. The collimating lens 53 collimates the ultraviolet light 9a diffused by the diffusion lens 52. The linear polarizing plate 54 converts the ultraviolet light 9a collimated by the collimating lens 53 into polarized UV 9b, which is the desired linearly polarized light. The spherical wave forming lens 55 adjusts the polarized UV 9b emitted from the linear polarizing plate 54 into a spherical wave shape as the exposure light 9c. The exposure light 9c emitted from the spherical waveforming lens 55 irradiates the photocrosslinkable polymer liquid crystal material CS coated on the second optical surface 21b.

[0032] In the spherical wave exposure described above, a substantially spherical wave with a gradient normal angle of d ± 5° or less is exposed to the second optical surface 21b of the lens member 21 on which the waveplate element 24 is provided. As a result, the waveplate element 24 has an orientation of d ± 5° or less with respect to the gradient normal angle d of the second optical surface 21b. Furthermore, the angle of incidence of light rays to the waveplate element 24 is limited to a maximum of 10° or less, and the angle difference during the three light rays incident on the waveplate element 24, as described later, can be kept to ±5% or less. At this time, the angle of incidence of light rays to the waveplate element 24 is considered as the angle of incidence with respect to the optical axis AX. The gradient normal angle d is the angle between the axis parallel to the optical axis AX and the normal to the second optical surface 21b. The angle difference of ±5° of the above-mentioned approximate spherical wave can be determined by considering the intersection point with the second optical surface 21b with respect to the optical axis AX, from (i) the difference between the normal direction at the intersection point of the optical axis AX and the second optical surface 21b (gradient normal angle d) and (ii) the difference between the direction vector of the optical axis AX and the intersection point of the spherical wave with the second optical surface 21b. Alternatively, when considering only the angle difference, the angle difference can be determined using the spherical wave vector at the intersection point of the ray with the second optical surface 21b and the normal vector of the second optical surface 21b. The gradient normal angle d with respect to the peripheral surface of the lens member 21 is greater than the gradient normal angle d with respect to the central surface of the lens member 21. As shown in Figure 4, when exposure is performed with a spherical wave having the same radius of curvature as the first radius of curvature R1, such that the angle of incidence of the light ray incident on the waveplate element 24 follows the curved surface gradient of the first radius of curvature R1 of the second optical surface 21b, the liquid crystal molecules are aligned in a manner that follows the gradient direction of the second optical surface 21b.

[0033] After irradiation with exposure light 9c, the thin film of the photocrosslinkable polymer liquid crystal material CS is annealed. This causes the molecular species exhibiting liquid crystalline properties, whose orientation state did not change due to ultraviolet light, to become liquid crystallized, and their orientation state can be matched to that of the polymer portion that is already in the desired orientation state. The orientation state is then fixed by subsequent cooling. In other words, a waveplate, i.e., a waveplate element 24, is obtained, which is made of a thin film in which the orientation directions of most of the molecular species exhibiting liquid crystalline properties constituting the photocrosslinkable polymer liquid crystal material CS are matched.

[0034] The polarizing optical element 25 is a wire grid polarizer that selectively reflects the first linear polarization L1 in the first polarization direction corresponding to the horizontal X direction, and selectively transmits only the second vertical polarization L2 in the second polarization direction corresponding to the vertical or bony Y direction. By making the polarizing optical element 25 a wire grid polarizer, the polarizing optical element 25 can be attached to the second optical surface 21b via the waveplate element 24, and even if the second optical surface 21b is a curved surface, it becomes relatively easy to form the polarizing optical element 25 on the second optical surface 21b. The polarizing optical element 25 is a reflective polarizer having a structure in which a large number of metal fine wires made of materials such as aluminum and nickel are arranged in parallel on a flexible transparent resin substrate, and this wire grid layer made of a large number of metal fine wires is covered with a transparent protective layer. The polarizing optical element 25 reflects linear polarization having an electric field component (corresponding to the polarization direction) that is parallel to the direction in which the large number of metal fine wires extend and perpendicular to the periodic direction corresponding to the arrangement direction. The body of the polarizing optical element 25 is manufactured by transferring the uneven shape to the surface of a resin film made of UV resin or thermoplastic resin using a mold having an uneven structure, and then depositing aluminum obliquely onto the tops and sides of the protrusions of the uneven shape using a vacuum deposition method. The body of the polarizing optical element 25 can also be manufactured by applying a polymer solution to a mold having an uneven structure using a spin coating method and curing the polymer solution formed on the surface of the mold (see, for example, Japanese Patent Application Publication No. 2011-221334). The polarizing optical element 25 obtained in this way is fixed to the lens member 21 by, for example, attaching it to the waveplate element 24 using an adhesive.

[0035] The polarizing optical element 25 does not have to be a wire grid polarizer; for example, it may be a polarizer of the type in which multiple films with anisotropy created by rolling are stacked, a multilayer film, or a dielectric multilayer film formed by vacuum deposition.

[0036] Figure 5 is a conceptual diagram illustrating the optical operation of the first virtual image display device 100A. As shown in Figure 5, the image light ML emitted from the display 10 passes through the first polarization control member PC1 and is converted to right-circularly polarized light C1. The right-circularly polarized image light ML incident on the optical member 20 from the display 10 partially passes through the reflective optical element 22, but is attenuated to about half its intensity during transmission. The image light ML that has passed through the reflective optical element 22 passes through the lens member 21 and then through the waveplate element 24. At this time, the image light ML is refracted by the lens member 21 and subjected to a relatively focusing effect by positive power. Furthermore, by passing through the waveplate element 24 in the forward direction, the image light ML is converted from right-circularly polarized light C1 to first linearly polarized light L1 in the first polarization direction and incident on the polarizing optical element 25. The image light ML incident on the polarizing optical element 25 is efficiently reflected by the polarizing optical element 25 while remaining in its first linear polarization L1 state, and as it passes through the lens member 21, it passes through the waveplate element 24 from the opposite direction. The image light ML that has passed through the waveplate element 24 from the opposite direction is converted to left circular polarization C2. The image light ML emitted from the lens member 21 after passing through the waveplate element 24 is reflected by the reflective optical element 22 and is relatively focused by positive power, but is attenuated to about half its intensity during reflection. The left circular polarization C2 image light ML reflected by the reflective optical element 22 passes through the lens member 21 and the waveplate element 24 from the forward direction, is converted to second linear polarization L2 in the second polarization direction, and is incident on the polarizing optical element 25. In the above, the image light ML travels back and forth through the lens member 21 due to reflection by the reflective optical element 22, passing through the lens member 21 twice in this back and forth motion, and as a result passes through the lens member 21 three times. The image light ML, which passes through the lens member 21 and enters the polarizing optical element 25, is efficiently transmitted through the polarizing optical element 25 while maintaining its second linear polarization L2 in the second polarization direction. The image light ML emitted outside the optical member 20 is collimated by the focusing action of the optical member 20 and enters the pupil position PP where the wearer's eye EY is located (see Figure 2). In other words, the wearer US wearing the first virtual image display device 100A can observe a virtual image produced by the image light ML.

[0037] Figure 6 is a diagram illustrating the setting conditions for the first virtual image display device 100A. As shown in Figure 6, for the HMD200 shown in Figure 1, the eye relief length D1 that fits the shape of the wearer's face US is set to 8 mm or more, and the F number of the optical element 20 is set to 1.0 to 2.0. The eye relief length D1 is the axial distance from the end of the second optical surface 21b of the lens member 21 that is closest to the pupil position PP on the axis, i.e., the first end surface 21d, to the pupil position PP. In this case, the first radius of curvature R1 of the reflective surface of the polarizing optical element 25 facing the second optical surface 21b of the lens member 21, and the second radius of curvature R2 of the reflective surface of the reflective optical element 22 facing the first optical surface 21a of the lens member 21 are set as follows. 0.8 ≤ R² / R1 ≤ 1.2 Here, the second optical surface 21b of the lens member 21 and the reflective surface of the polarizing optical element 25 are considered to have the same or substantially the same first radius of curvature R1. Also, the first optical surface 21a of the lens member 21 and the reflective surface of the reflective optical element 22 are considered to have the same or substantially the same second radius of curvature R2. Furthermore, if the first and second optical surfaces 21a and 21b of the lens member 21 are aspherical, the first and second radii of curvature R1 and R2 are considered to be approximate radii of curvature.

[0038] Furthermore, the ratio of the radii of curvature (R2 / R1) preferably satisfies the following conditions. 1.0 ≤ R² / R1 ≤ 1.2

[0039] As previously described, in the first display optical system 103a, the image light ML emitted from the display unit 10 is incident three times on the waveplate element 24 provided on the second optical surface 21b of the lens member 21. By incidenting the image light ML on the waveplate element 24 three times, the light ray can be folded while converting linearly polarized light in a predetermined direction, for example, horizontally polarized light to vertically polarized light. At this time, considering the passage and reflection angles of each angle of view light ray, and tracing the light ray from the pupil position PP side, the coordinate positions (z,r) of points P1 to P6 shown in Figure 6, and the angle of the incident light ray on the waveplate element 24 can be calculated as follows.

[0040] The equation for the angle of view ray emitted from point P1 is expressed as follows: Regarding the coordinates of point P2 in TIFF2026066527000002.tif12169, the surface equation (1) of the second optical surface 21b is expressed as follows. For simplification, the lens surface of the second optical surface 21b is assumed to be spherical, and the angle of light rays with respect to the direction of the lens surface normal is considered. The gradient of the lens surface at point (z,r) is expressed as follows by differentiating the surface equation (1) in the direction of radius r. TIFF2026066527000004.tif20169 Furthermore, the normal to the surface at point (z,r) is given by -1 / z'. According to this formula, the refraction and reflection within the lens member 21 can be calculated, and although not shown in the illustration, the rays at each angle of view can be plotted as graphs.

[0041] When considering the effect of the angle of incidence of light on the waveplate element 24 (viewing angle characteristics), the direction of polarized UV exposure (optical axis of the phase difference plate) when fabricating the phase difference function of the waveplate element 24 becomes important. As shown in Figure 7, as a comparative example, when plane wave exposure is performed in the optical axis AX direction of the lens member 21, the liquid crystal molecules will be aligned in the direction along the plane wave. Note that plane wave exposure is performed in the exposure apparatus 50 shown in Figure 3, with the spherical wave forming lens 55 removed.

[0042] Figure 8 is a graph illustrating the angle of incidence of light rays (angle with respect to the optical axis AX direction) when light passes through the waveplate element 24 during plane wave exposure in the optical path from point P2 to point P4 shown in Figure 6, as a comparative example. Figure 8 shows the results of calculating the angle of incidence of light rays (angle of light ray passage) to the waveplate element 24 with respect to the normal of the second optical surface 21b (surface with first radius of curvature R1) for the entire field of view of the first display optical system 103a.

[0043] As shown in Figure 8, for light rays at the edge of the field of view, the incident angle exceeds 50°. However, for good image characteristics, the waveplate element 24 needs to be able to handle angles exceeding 50° as part of its field of view characteristics. However, considering the general field of view characteristics of the waveplate element 24 shown in Figure 9, 50° is quite difficult, and the waveplate element 24 deviates significantly from the phase difference of 0.25 wavelengths that it targets.

[0044] Therefore, when exposing the waveplate element 24 with a spherical wave of the same radius of curvature as the first radius of curvature R1, such that the angle of incidence of the light rays incident on the waveplate element 24 follows the slope of the curved surface of the first radius of curvature R1 corresponding to the second optical surface 21b, the liquid crystal molecules will be aligned in the direction of the slope of the second optical surface 21b, as shown in Figure 4. The angle of incidence of the light rays passing through the waveplate element 24 can be considered as the angle with respect to the normal direction of the curved surface of the first radius of curvature R1 corresponding to the second optical surface 21b. Figure 10 is a graph showing the angle of incidence of the light rays to the waveplate element 24 for spherical wave exposure in this embodiment with respect to the normal of the second optical surface 21b (the curved surface of the first radius of curvature R1) for the entire field of view. As shown in Figure 10, compared to the comparative example shown in Figure 8, the angle of incidence of the light rays is less than 1 / 5, and this level of field of view characteristic is considered realistic. In addition, the amount of deviation of the waveplate element 24 from the target phase difference is also small.

[0045] On the other hand, as shown in Figure 2, the angle of incidence of light rays on the waveplate element 24 is determined by the focusing state of light rays within the first display optical system 103a, that is, by the power distribution of the optical surface from the pupil position PP to the image display panel 11. In particular, the ratio of the radii of curvature of the two reflective surfaces, specifically the ratio of the first radius of curvature R1 of the polarizing optical element 25 to the second radius of curvature R2 of the reflective optical element 22, is important. Since the first radius of curvature R1 and the second radius of curvature R2 are determined by the F number of the lens member 21, the ratio of the F number to the radius of curvature (R2 / R1), and the angle of incidence of light rays on the waveplate element 24 (global and surface normal reference) were investigated.

[0046] Figure 11 is a graph showing the relationship between the F-number and the ratio of the radius of curvature (R2 / R1). As shown in Figure 11, if the F-number is less than 1.0, the desired optical properties cannot be obtained, and the design generally becomes difficult. Therefore, when examined in the region where the F-number is 1.0 or greater, the ratio of the radius of curvature (R2 / R1) satisfies the following conditions. 0.8 ≤ R² / R1 ≤ 1.2

[0047] Furthermore, if the F number is 1.0 or greater, it is preferable that the ratio of the radii of curvature (R2 / R1) satisfies the following conditions. 1.0 ≤ R² / R1 ≤ 1.2

[0048] Furthermore, the number of incident beams on the waveplate element 24 and the incident angle of the field-edge ray are compared for plane wave exposure and spherical wave exposure. Region BR1 in Figure 12 is a graph showing the incident angle of the waveplate element 24 for spherical wave exposure at the field-edge ray, as an example. Region BR2 in Figure 12 is a graph showing the incident angle of the waveplate element 24 for plane wave exposure at the field-edge ray, as a comparative example. In Figure 12, QWP represents the waveplate element 24. As shown in region BR1 in Figure 12, when spherical wave exposure is performed with respect to the surface normal, the incident angle is generally 10° or less, except when the F number is 0.9 and 1.0. On the other hand, as shown in region BR2 in Figure 12, when plane wave exposure is performed with respect to the optical axis AX, the incident angle on the waveplate element 24 is generally 50° or more.

[0049] Next, the image characteristics (specifically, brightness unevenness, color unevenness, and ghosting) within the display screen are compared using a simulation for both plane wave exposure and spherical wave exposure. In the simulation, output information regarding the pupil position PP (see Figure 2) in relation to the input information was calculated. Specifically, between the input information and the output information regarding the image, calculations were performed sequentially for the circular polarizer 16 (linear polarizer 14 and quarter wave plate 15), reflective optical element 22, wave plate element 24, polarizing optical element 25, wave plate element 24, reflective optical element 22, wave plate element 24, and polarizing optical element 25. Specifically, polarization calculations of Stokes vectors using Muller matrices were performed for spectral intensity and polarization state. The input information includes the field of view and the spectral intensity of the image light ML. In addition, information such as the incident angle and polarization state is input as appropriate for the calculations for each element 16, 22, 24, and 25.

[0050] Figure 13 is a graph showing the results of comparing brightness unevenness, color unevenness, and ghosting (image light ratio) at each F-number field of view position (one side) for plane wave exposure and spherical wave exposure. Region CR1 in Figure 13 is a graph showing the brightness ratio at the field of view position of the example. Region CR2 in Figure 13 is a graph showing the brightness ratio at the field of view position of the comparative example. Region CR3 in Figure 13 is a graph showing the chromaticity change at the field of view position of the example. Region CR4 in Figure 13 is a graph showing the chromaticity change at the field of view position of the comparative example. Region CR5 in Figure 13 is a graph showing the ghosting ratio at the field of view position of the example. Region CR6 in Figure 13 is a graph showing the ghosting ratio at the field of view position of the comparative example. The ghosting ratio is the ratio of the brightness of ghosting to the brightness of the image area or image light.

[0051] As shown in regions CR1 and CR2 of Figure 13, compared to plane wave exposure, spherical wave exposure shows a 10% improvement in brightness uniformity within the image. As shown in regions CR3 and CR4 of Figure 13, although the influence of the viewing angle characteristics of the waveplate element 24 is originally small, an improvement in color uniformity can be seen. Regarding chromaticity changes, a level exceeding 0.01 becomes visible as color uniformity. As shown in regions CR5 and CR6 of Figure 13, regarding ghosting, in the case of plane wave exposure, 60% of the image light ML is ghosting, whereas in the case of spherical wave exposure, it can be reduced to about 1% to 2%, and a significant improvement can be expected.

[0052] (Example 1) The following describes Example 1 of this embodiment. The parameters of the first display optical system 103a of Example 1 are shown below. Each reference numeral corresponds to the reference numerals shown in Figures 2 and 6. FOV: 100° Lens thickness D3: 7.3mm Distance D2 from pupil position PP to the center of the second optical surface 21b: 14.2 mm First radius of curvature R1 of the second optical surface 21b: -21.40 mm Second radius of curvature R2 of the first optical surface 21a: -23.60 mm Ratio of radii of curvature (R2 / R1) = 1.103

[0053] (Example 2) The following describes Example 2 of this embodiment. The parameters of the first display optical system 103a in Example 2 are shown below. FOV: 100° Lens thickness D3: 7.3mm Distance D2 from pupil position PP to the center of the second optical surface 21b: 13.3 mm First radius of curvature R1 of the second optical surface 21b: 21.70 mm Second radius of curvature R2 of the first optical surface 21a: 21.64 mm Ratio of radii of curvature (R2 / R1) = 0.997

[0054] In Examples 1 and 2, the configuration direction of the waveplate element 24, that is, the exposure direction of polarized UV, is configured as spherical wave exposure along the normal direction of the curved surface of the second optical surface 21b. In this case, the incident angle when the light ray passes through the waveplate element 24 is as shown in Figure 10. As shown in Figure 10, the incident angle is a maximum of 8° across the entire field of view, and the waveplate element 24 also only requires a field of view characteristic of 8°. Therefore, the retardation difference of the waveplate element 24 due to the field of view is reduced, and the phase change is performed almost accurately across all wavelengths of the video light ML emitted from the image display panel 11. As a result, brightness unevenness, color unevenness, and ghosting of the displayed image can be suppressed.

[0055] Furthermore, if the region through which light rays at the edge of the field of view pass is exposed with a spherical wave tilted to ±5° or less with respect to the normal angle along the curved surface gradient of the second optical surface 21b, the required field of view characteristics for the waveplate element 24 can be limited to within ±5°, thereby improving image quality.

[0056] Figure 14 illustrates the verification of the field of view characteristics of the waveplate element 24. As shown in Figure 14, the observation device 60 includes a camera 61, a first polarizer 62, a second polarizer 63, and a light source 64. The polarization direction of the first polarizer 62 and the polarization direction of the second polarizer 63 are orthogonal. A lens member 21, on which the waveplate element 24, the object to be observed, is placed between the first polarizer 62 and the second polarizer 63, and the camera 61 is moved to observe the crossed nicol pattern of the waveplate element 24 illuminated by the light source 64. This allows for the quantitative measurement of the phase difference of the waveplate element 24 on the second optical surface 21b. The pattern (phase difference) of the crossed nicol pattern changes depending on the viewing angle. In the case of a sample exposed with spherical wave exposure, when observed from the front, the color appears to change between the center and the edges of the optical surface. Also, in the case of a sample exposed with spherical wave exposure, when observed from an oblique angle, the edges of the optical surface appear to be the same color as the center of the optical surface when viewed from the front, depending on the viewing angle. From the above, it can be seen that the phase difference between the center of the optical surface viewed from the front and the edge of the optical surface viewed from an oblique angle is the same. On the other hand, in the case of a sample exposed with a plane wave, when viewed from the front, the entire surface of the second optical surface 21b appears to be the same color.

[0057] Furthermore, the phase difference can also be measured by, for example, a phase difference measurement method. In the phase difference measurement method, the polarization state of the input is changed to, for example, four polarization states (specifically, horizontal polarization, vertical polarization, right circular polarization, and left circular polarization), and each polarization is irradiated onto the lens member 21 equipped with a waveplate element 24. By measuring the received light intensity for each polarization of the light transmitted through the waveplate element 24, the amount of phase change of the waveplate element 24 can be determined.

[0058] The first embodiment of the virtual image display device 100A, 100B and optical unit 100 described above comprises a display 10 that emits circularly polarized image light ML, and an optical member 20 that forms a virtual image by reflecting the image light ML twice. The optical member 20 comprises a lens member 21 having one or more lenses, a transmissive reflective optical element 22 provided facing the first optical surface 21a of the lens member 21 that is close to the display 10, and a first optical element provided facing the second optical surface 21b of the lens member 21 that is farther from the display 10. The system includes a reflective polarizing optical element 25 that reflects image light ML which is linearly polarized in the polarization direction, and a waveplate element 24 provided between the reflective optical element 22 and the polarizing optical element 25, formed of a photocrosslinkable polymer liquid crystal material CS, which polarizes the image light ML that has passed through the reflective optical element 22 into linearly polarized light in a first polarization direction, and the image light ML that is reflected by the reflective optical element 22 and returns into linearly polarized light in a second polarization direction, wherein the waveplate element 24 has an orientation of d ± 5° or less with respect to the gradient normal angle d of the optical surface on which the waveplate element 24 is provided.

[0059] In the above-described virtual image display device, the waveplate element 24 has an orientation along the gradient of the optical surface of the lens member 21, specifically the second optical surface 21b, thereby enabling the lens member 21 to function as a waveplate substantially aligned with the shape of the optical surface. This makes it possible to suppress the degradation of the image quality of the displayed image (specifically, brightness unevenness, color unevenness, and ghosting).

[0060] Note that the first and second polarization directions are for convenience only, and the specific definitions of the directions can be interchanged. In other words, in the example shown in Figure 2, the polarizing optical element 25 reflects the first polarization L1 in the first polarization direction which is the X direction, but the polarizing optical element 25 may also reflect the first polarization L1 in the first polarization direction which is the Y direction.

[0061] [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.

[0062] Figure 15 is a side cross-sectional view illustrating the optical structure of the display optical systems 103a and 103b of the virtual image display devices 100A and 100B of the second embodiment. As shown in Figure 15, in the first display optical system 103a, the lens member 21 of the optical member 20 is a meniscus lens having positive power as a whole, but has two or more lenses 121 and 221. That is, the lens member 21 has a first lens 121 and a second lens 221 in order from the display 10 side. The first lens 121 and the second lens 221 are bonded together via a waveplate element 24.

[0063] The third optical surface 21f on the exit side of the first lens 121 is concave, and the fourth optical surface 21g on the incident side of the second lens 221 is convex. The radius of curvature of the fourth optical surface 21g is the same as or approximately the same as the radius of curvature of the third optical surface 21f. In this case, the waveplate element 24 has a shape that follows the curved third optical surface 21f and the fourth optical surface 21g. That is, the waveplate element 24 is provided between the first optical surface 21a and the second optical surface 21b and is embedded inside the lens member 21.

[0064] The lens member 21 is configured as follows with respect to the first radius of curvature R1 of the second optical surface 21b on the exit side and the second radius of curvature R2 of the first optical surface 21a on the incident side of the lens member 21. 0.8 ≤ R² / R1 ≤ 1.2

[0065] Furthermore, the ratio of the radii of curvature (R2 / R1) preferably satisfies the following equation. 1.0 ≤ R² / R1 ≤ 1.2

[0066] The lens member 21 is formed by applying a photocrosslinkable polymer liquid crystal material CS to either the fourth optical surface 21g of the second lens 221 or the third optical surface 21f of the first lens 121, and then performing spherical wave exposure to form the waveplate element 24. In this case, in the spherical wave exposure shown in Figure 4, a substantially spherical wave of d ± 5° or less is exposed to the gradient normal angle d of the optical surface of the lens member 21 coated with the photocrosslinkable polymer liquid crystal material CS (in the example of Figure 15, the fourth optical surface 21g of the second lens 221). One of the first and second lenses 121, 221 serves as the substrate, and the other functions as a cover glass. By sealing the periphery of the lens member 21 with an adhesive or the like, the intrusion of moisture and the like can be prevented, and the deterioration of the waveplate element 24 can be suppressed.

[0067] By using different refractive indices for the first lens 121 and the second lens 221, a lens effect can be created between the glass materials, leading to further improvements in resolution, and consequently, miniaturization, thinning, and weight reduction of the entire optical system.

[0068] Furthermore, when the lens member 21 is composed of two or more lenses, a waveplate element 24 may be provided between the second optical surface 21b and the polarizing optical element 25, as shown in Figure 16. Also, a gap may be provided between the first lens 121 and the second lens 221. In this case, the waveplate element 24 is provided, for example, on the second lens 221 on which the polarizing optical element 25 is provided. Specifically, the waveplate element 24 is provided on the fourth optical surface 21g on the incident side or the second optical surface 21b on the exit side of the second lens 221.

[0069] [Differentiations 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.

[0070] Figure 17 illustrates the fabrication of a modified waveplate element 24 of the first embodiment. As shown in Figure 17, in the fabrication of the waveplate element 24, the refractive effect of the first optical surface 21a of the lens member 21 may be utilized to perform plane wave exposure on the photocrosslinkable polymer liquid crystal material CS coated on the second optical surface 21b from the first optical surface 21a side, i.e., the curved surface side with the second radius of curvature R2. In this case, the first and second radii of curvature R1 and R2 of the lens member 21 are adjusted so that the angle difference between the angle of incidence of the exposure light 9c and the gradient normal angle d is ±5° or less. The first and second radii of curvature R1 and R2 are set to satisfy, for example, the following equation. R² = 0.6 * R1

[0071] (Example 3) The following describes a modified example, Example 3. The parameters of the first display optical system 103a in Example 3 are shown below. FOV: 100° Lens thickness D3: 8.8mm Distance D2 from pupil position PP to the center of the second optical surface 21b: 13.3 mm First radius of curvature R1 of the second optical surface 21b: 48.90 mm Second radius of curvature R2 of the first optical surface 21a: 29.50 mm Ratio of radii of curvature (R2 / R1) = 0.603

[0072] In the above embodiment, the lens member 21 incorporated into the optical member 20 is merely an example and may include one or two lenses joined together or separated. Even when the lens member 21 is composed of two or more lenses, the ratio of the radii of curvature (R2 / R1) is considered with respect to the first radius of curvature R1 of the optical surface facing the reflective surface of the polarizing optical element 25 and the second radius of curvature R2 of the optical surface facing the reflective surface of the reflective optical element 22.

[0073] The optical element 20 is not required to have an FOV of 100° or more, but it is desirable that the thickness from the display unit 10 to the outer edge or the rear end ejection surface 21c of the optical element 20 be 20 mm or less.

[0074] 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.

[0075] The polarization states shown in Figure 2, etc., are illustrative examples. For example, the image light ML emitted from the display unit 10 can be left-circularly polarized. In this case, the polarizing optical element 25 must selectively reflect only linearly polarized light (vertical polarization) in the polarization direction corresponding to the vertical Y direction, and selectively transmit linearly polarized light (horizontal polarization) in the polarization direction corresponding to the horizontal X direction.

[0076] When fabricating the waveplate element 24, the exposure of the photocrosslinkable polymer liquid crystal material CS is not limited to being performed from the optical surface side to which the photocrosslinkable polymer liquid crystal material CS is coated, but may also be performed from the optical surface side opposite to the optical surface to which the photocrosslinkable polymer liquid crystal material CS is coated. In this case as well, the exposure is performed so that the gradient normal angle d of the optical surface on which the waveplate element 24 is provided is d ± 5° or less.

[0077] In a specific embodiment, the first virtual image display device includes a display that emits circularly polarized image light, and an optical member that forms a virtual image by reflecting the image light twice. The optical member includes a lens member having one or more lenses, a transmissive reflective optical element provided opposite a first optical surface of the lens member that is close to the display, a reflective polarizing optical element provided opposite a second optical surface of the lens member that is far from the display and reflects image light that is linearly polarized in a first polarization direction, and a waveplate element provided between the reflective optical element and the polarizing optical element, made of a photocrosslinkable polymer liquid crystal material, which polarizes the image light that has passed through the reflective optical element into linearly polarized light in a first polarization direction, and the image light that is reflected by the reflective optical element and returns into linearly polarized light in a second polarization direction. The waveplate element has an orientation of d ± 5° or less with respect to the gradient normal angle d of the optical surface on which the waveplate element is provided.

[0078] In the above-described virtual image display device, the waveplate element has an orientation that follows the gradient of the optical surface of the lens member, thereby enabling the lens member to function as a waveplate substantially aligned with the shape of the optical surface. This makes it possible to suppress the degradation of the image quality of the displayed image (specifically, brightness unevenness, color unevenness, and ghosting).

[0079] In a specific embodiment of a virtual image display device, the lens member has an F number of 1 or more, and when the first curvature of the second optical surface is R1 and the second curvature of the first optical surface is R2, it satisfies the following equation. 0.8 ≤ R² / R1 ≤ 1.2 In this case, by satisfying the above formula with respect to the first and second optical surfaces of the lens member, the radius of curvature of the reflective optical element as a reflective surface facing the first optical surface and the radius of curvature of the polarizing optical element as a reflective surface facing the second optical surface can be controlled, thereby reducing the difference in ray angle when light is incident on the waveplate element three times. This can further improve the displayed image.

[0080] In a specific embodiment of the virtual image display device, the waveplate element is provided between the second optical surface and the polarizing optical element.

[0081] In a specific embodiment of a virtual image display device, the lens member has two or more lenses, and the waveplate element is provided between the first optical surface and the second optical surface.

[0082] In a specific embodiment of the virtual image display device, the first optical surface is convex, and the second optical surface is concave. The convex nature of the first optical surface allows the reflective optical element to be given positive power, making it easier to miniaturize the virtual image display device by reducing the distance between the display and the optical components. Furthermore, the concave nature of the second optical surface reduces the overall refraction of the principal ray at the second optical surface of the lens component, facilitating the reduction of aberrations in the optical components.

[0083] In a specific embodiment of a virtual image display device, the polarizing optical element is one of a wire grid polarizer, a multilayer film, or a dielectric multilayer film. In this case, even if the optical surface is curved, it becomes relatively easy to form the polarizing optical element on the optical surface.

[0084] In a specific embodiment of a virtual image display device, the display unit includes an image display panel and a polarization control member that makes the image light emitted from the image display panel circularly polarized.

[0085] In a specific embodiment of a virtual image display device, the polarization control member includes, in order from the image display panel side, a linear polarizer and a waveplate.

[0086] In a specific embodiment of a virtual image display device, the lens member has a first end face extending radially perpendicular to the optical axis from a second optical surface, and a second end face perpendicular to the first end face. In this case, the first and second end faces function as positioning parts or positioning surfaces.

[0087] In a specific embodiment of a virtual image display device, the lens member has a first end face extending radially from the second optical surface perpendicular to the optical axis, and the first end face is exposed without a waveplate element or polarizing optical element. In this case, it is possible to prevent unwanted reflection of image light.

[0088] In a specific embodiment, the optical unit comprises a display that emits circularly polarized image light, and an optical element that reflects the image light twice to form a virtual image. The optical element includes a lens member having one or more lenses, a transmissive reflective optical element provided opposite a first optical surface of the lens member that is close to the display, a reflective polarizing optical element provided opposite a second optical surface of the lens member that is far from the display and reflects image light that is linearly polarized in a first polarization direction, and a waveplate element provided between the reflective optical element and the polarizing optical element, made of a photocrosslinkable polymer liquid crystal material, which polarizes the image light that has passed through the reflective optical element into linearly polarized light in a first polarization direction, and the image light that is reflected by the reflective optical element and returns into linearly polarized light in a second polarization direction. The waveplate element has an orientation of d ± 5° or less with respect to the gradient normal angle d of the optical surface on which the waveplate element is provided. [Explanation of symbols]

[0089] 10…Display unit, 11…Image display panel, 14…Linear polarizer, 15…Quarter wave plate, 16…Circular polarizer, 20…Optical component, 21…Lens component, 21a,21b,21f,21g…Optical surface, 22…Reflective optical element, 24…Waveplate element, 25…Polarizing optical element, 50…Exposure device, 60…Observation device, 80…Circuit component, 90…User terminal, 100…Optical unit, 100A,100B…Virtual image display device, 102…Drive device, 102a,102b…Display drive unit, 103a,103b…Display optical system, 200…Head-mounted display device, AX…Optical axis, CS…Photocrosslinkable polymer liquid crystal material, EY…Eye, ML…Image light, PC1,PC2…Polarization control component, PP…Pupil position, US…Wearer

Claims

1. A display that emits circularly polarized image light, The optical member comprises an optical element that reflects the aforementioned image light twice to form a virtual image, The optical component is A lens component having one or more lenses, A transmissive reflective optical element is provided facing the first optical surface of the lens member that is close to the display, A reflective polarizing optical element is provided opposite the second optical surface of the lens member that is farther from the display, and reflects image light that is linearly polarized in the first polarization direction, The device includes a waveplate element provided between the reflective optical element and the polarizing optical element, formed of a photocrosslinkable polymer liquid crystal material, which polarizes the image light that has passed through the reflective optical element in a first polarization direction and the image light that has been reflected by the reflective optical element and is returning in a second polarization direction, The waveplate element has an orientation of d ± 5° or less with respect to the gradient normal angle d of the optical surface on which the waveplate element is provided. Virtual image display device.

2. The lens member has an F-number of 1 or more, and when the first radius of curvature of the second optical surface is R1 and the second radius of curvature of the first optical surface is R2, it satisfies the following equation: The virtual image display device according to claim 1. 0.8 ≤ R² / R¹ ≤ 1.2

3. The waveplate element is provided between the second optical surface and the polarizing optical element. The virtual image display device according to claim 1.

4. The aforementioned lens member has two or more lenses, The waveplate element is provided between the first optical surface and the second optical surface. The virtual image display device according to claim 1.

5. The first optical surface is a convex surface, The second optical surface is concave. The virtual image display device according to claim 1.

6. The polarizing optical element is one of a wire grid polarizer, a multilayer film, or a dielectric multilayer film. The virtual image display device according to claim 1.

7. The display unit comprises an image display panel and a polarization control member that makes the image light emitted from the image display panel circularly polarized. The virtual image display device according to claim 1.

8. The polarization control member comprises, in order from the image display panel side, a linear polarizer and a waveplate. The virtual image display device according to claim 7.

9. The lens member has a first end face extending radially perpendicular to the optical axis from the second optical surface, and a second end face perpendicular to the first end face. The virtual image display device according to claim 1.

10. The lens member has a first end face extending radially from the second optical surface perpendicular to the optical axis, The first end face is not provided with the waveplate element and the polarizing optical element, and its surface is exposed. The virtual image display device according to claim 1.

11. A display that emits circularly polarized image light, The optical member comprises an optical element that reflects the aforementioned image light twice to form a virtual image, The optical component is A lens component having one or more lenses, A transmissive reflective optical element is provided facing the first optical surface of the lens member that is close to the display, A reflective polarizing optical element is provided opposite the second optical surface of the lens member that is farther from the display, and reflects image light that is linearly polarized in the first polarization direction, The device includes a waveplate element provided between the reflective optical element and the polarizing optical element, formed of a photocrosslinkable polymer liquid crystal material, which polarizes the image light that has passed through the reflective optical element in a first polarization direction and the image light that has been reflected by the reflective optical element and is returning in a second polarization direction, The waveplate element has an orientation of d ± 5° or less with respect to the gradient normal angle d of the optical surface on which the waveplate element is provided. Optical unit.

Images