Virtual image display device

Abstract

To provide a virtual image display device that is easy to be miniaturized and manufactured, and exhibits excellent optical characteristics at a wide visual field angle.SOLUTION: A virtual image display device comprises: a display element that emits image light to a first side in a first direction; a first lens formed of a curved surface protruding toward the display element; a second lens formed of a curved surface protruding toward the display element; a first polarizing layer that is formed along the curved surface on the first side of the second lens, transmits first polarized light, and reflects second polarized light different from the first polarized light on a second side; a second polarizing layer that transmits the first polarized light; a first wavelength layer that is formed along the curved surface on the first side of the first lens, imparts a phase difference to incident light and transmits the incident light; a reflection layer that transmits part of the incident light and reflects remaining part of the incident light; and a second wavelength layer that is formed along the curved surface on the first side of the first lens, imparts a phase difference to the incident light, and transmits the incident light.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a virtual image display device. [Background technology]

[0002] Virtual image display devices that enable the observation of a virtual image by guiding image light emitted from a display element to the observer's eyes using optical elements such as lenses have been known for some time. For example, Patent Document 1 discloses a virtual image display device that includes an image element that displays an image, a first optical unit arranged on the optical path of the image light, a second optical unit arranged closer to the image element than the first optical unit, a half mirror provided on a sawtooth surface formed at the junction between the first optical unit and the second optical unit, and a transmission / reflection selection member provided on the exit side of the first optical unit. The transmission / reflection selection member selectively transmits or reflects light depending on the polarization state of the incident light.

[0003] Patent Document 2 discloses a thermoformed multilayer reflective polarizer used to guide image light from a display element. The thermoformed multilayer reflective polarizer is formed substantially rotationally symmetrical with respect to the optical axis of the image light passing through the vertex, and is formed convex with respect to a plane perpendicular to the optical axis. In the thermoformed multilayer reflective polarizer, s1 / r1 is 0.2, where r1 is the radius around the optical axis and s1 is the displacement on the plane perpendicular to the optical axis. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-024246 [Patent Document 2] Special Publication No. 2018-500584 Summary of the Invention [Problem to be solved by the invention]

[0005] In the virtual image display device disclosed in Patent Document 1, the design and manufacture of the sawtooth surface of the optical element are somewhat complicated. The thermoformed multilayer reflective polarizer disclosed in Patent Document 2 does not provide optical properties such as imaging characteristics at a wide viewing angle, making it difficult to configure a telecentric optical system on the display element side and shortening the distance from the display element to the optical element located closest to the viewer. Therefore, there is a need for a virtual image display device that is compact, easy to manufacture, and exhibits excellent optical properties at a wide viewing angle. [Means for solving the problem]

[0006] The virtual image display device of this embodiment includes a display element that emits image light to a first side along a first direction, a first lens that is arranged on the first side of the display element and has a curved surface that protrudes toward the display element, a second lens that is arranged on the first side of the first lens and has a curved surface that protrudes toward the display element, the radius of curvature of the curved surface on the first side being larger than the radius of curvature of the curved surface on a second side opposite to the first side in the first direction, a first polarizing layer that is arranged on the first side of the second lens and is formed along the curved surface on the first side of the second lens, and transmits a first polarized light of the incident light and reflects a second polarized light of the incident light that is different from the first polarized light, and a second polarized light that is arranged on the first side of the second lens and has a curved surface that protrudes toward the display element, the radius of curvature of the curved surface on the first side being larger than the radius of curvature of the curved surface on a second side opposite to the first side in the first direction, and a a second polarizing layer disposed between the second polarizing layer and the second lens in the first direction and transmitting a first polarized light of the incident light; a first wavelength layer disposed between the second polarizing layer and the second lens in the first direction and formed along the curved surface of the first side of the first lens and transmitting the incident light with a phase difference equivalent to ¼ of the wavelength of the light; a reflective layer disposed between the first wavelength layer and the second lens in the first direction and transmitting a portion of the incident light and reflecting the remainder of the incident light; and a second wavelength layer disposed between the reflective layer and the first polarizing layer in the first direction and formed along the curved surface of the first side of the first lens and transmitting the incident light with a phase difference equivalent to ¼ of the wavelength of the light. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram illustrating a configuration of a virtual image display device according to a first embodiment. [Figure 2]FIG. 1 is a partial exploded view showing the configuration of a virtual image display device according to a first embodiment. [Figure 3] 2 is an exploded side view for explaining the path of image light in the virtual image display device of FIG. 1. FIG. [Figure 4] FIG. 10 is a schematic diagram showing the configuration of a virtual image display device according to a second embodiment. [Figure 5] FIG. 10 is a schematic diagram showing the configuration of a virtual image display device according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In each drawing, the scale of the dimensions of some components may be changed to make the components easier to see.

[0009] [First embodiment] First, a first embodiment of the present invention will be described with reference to Fig. 1 to Fig. 3. Fig. 1 is a schematic diagram of a virtual image display device 11 of the first embodiment. As shown in Fig. 1, the virtual image display device 11 includes a display element 50, a lens 101, a polarizing layer 111, a quarter-wave layer 121, a reflective layer 131, a lens 102, a quarter-wave layer 141, and a polarizing layer 151.

[0010] In the virtual image display device 11, the display element 50, lens 101, polarizing layer 111, 1 / 4 wavelength layer 121, reflective layer 131, 1 / 4 wavelength layer 141, lens 102, polarizing layer 151, and the observer's eye EY are arranged sequentially from the -Z side to the +Z side along the Z direction.

[0011] The display element 50 displays an image or video of an object visually recognized by an observer and emits image light. The display element 50 is not limited to a specific type of element, but may be, for example, an image element configured with a self-luminous OLED (Organic Light Emitting Diode) such as an organic electroluminescence (Organic Electro-Luminescence), or a self-luminous display element such as an inorganic EL, an LED array, a laser array, or a quantum dot light-emitting element.

[0012] The display element 50 has a display surface 50p that emits the image light L1. A plurality of pixels (not shown) are provided along the X direction and the Y direction on the display surface 50p of the display element 50. That is, a plurality of pixels are two-dimensionally arranged on the display surface 50p.

[0013] In the following description and drawings, two mutually orthogonal directions included in a plane parallel to the display surface 50p of the display element 50 are referred to as the X direction and the Y direction. A direction orthogonal to the X direction and the Y direction and parallel to the optical axis of the image light L1 displayed from the display surface 50p of the display element 50 is referred to as the Z direction. One side in the X direction is referred to as the -X side, and the other side in the X direction is referred to as the +X side. One side in the Y direction is referred to as the -Y side, and the other side in the Y direction is referred to as the +Y side. One side in the Z direction is referred to as the -Z side, and the other side in the Z direction is referred to as the +Z side. The centers in the X direction and the Y direction of the display element 50, the lens 101, the polarizing layer 111, the quarter-wave layer 121, the reflective layer 131, the quarter-wave layer 141, the lens 102, the polarizing layer 151, and the viewer's eye EY overlap with each other.

[0014] The image light L1 is emitted toward the +Z side from each pixel on the display surface 50p of the display element 50, and is emitted so as to spread within the XY plane including the X and Y directions as it moves toward the +Z side, passing through the approximate center of each pixel and based on an axis parallel to the Z direction. The viewer's eye EY is located on the +Z side of the display element 50.

[0015] The lens 101 corresponds to a first lens. The lens 101 is disposed on the +Z side of the display element 50 and on the −Z side of the viewer's eye EY, and is disposed on the optical path of the image light L1 emitted from the display element 50 along the Z direction.

[0016] The lens 101 has a first surface 101a on the -Z side and a second surface 101b on the +Z side. The first surface 101a is a curved surface that protrudes toward the display element 50 in the Z direction, for example, an aspherical surface that protrudes toward the -Z side. The first surface 101a of the lens 101 is coated with an anti-reflection coating (not shown), or is provided with an anti-reflection film (not shown). The second surface 101b is a curved surface that protrudes toward the display element 50 in the Z direction, for example, an aspherical surface that protrudes toward the -Z side. The lens 101 focuses light incident from the -Z side toward the center of the XY plane and toward the eye EY on the +Z side.

[0017] The shape, radius of curvature, and aspherical coefficient of the first surface 101a and the shape, radius of curvature, and aspherical coefficient of the second surface 101b are appropriately set based on the results of a simulation using ray tracing that takes into account the path of light rays in the virtual image display device 11, which will be described later, and depending on the size of the display surface 50p of the display element 50 in the X and Y directions, the distance between the display element 50 and the viewer's eye EY in the Z direction, and the refractive index of each component of the virtual image display device 11.

[0018] The lens 101 is made of a material that is translucent to image light in the visible wavelength band, for example, a resin such as plastic. An example of the resin material for the lens 101 is OKP-1 (manufactured by Osaka Gas Chemicals Co., Ltd.), which is a low birefringence material and an optical polyester resin.

[0019] The polarizing layer 111 is in contact with the second surface 101b of the lens 101 from the +Z side and is provided on the second surface 101b. The polarizing layer 111 has a first surface 111a on the -Z side and a second surface 111b on the +Z side. The polarizing layer 111 transmits only predetermined linearly polarized light of the incident light. The predetermined polarized light is, for example, linearly polarized light with a vibration direction parallel to the Y direction.

[0020] As described above, polarizing layer 111 is not limited to a specific type of element as long as it is a polarizing layer that transmits only predetermined linearly polarized light, but is preferably composed of wire grid polarizer 211. Figure 2 is a side view of some of the components of virtual image display device 11, and is an enlarged view of each component in the Z direction as viewed from a direction perpendicular to the Z direction.

[0021] 2, the polarizing layer 111 has a wire-grid polarizer 211 and a base film 212. The wire-grid polarizer 211 is in contact with the second surface 101b on the +Z side of the lens 101, is provided on the second surface 101b, and has a substantially constant thickness along the second surface 101b. The thickness of the wire-grid polarizer 211, i.e., the thickness of the multiple wires of the wire-grid polarizer 211, is 1 μm or less, and specifically, is about several hundred nm.

[0022] Base film 212 is in contact with second surface 211b, which is the curved surface on the +Z side of wire-grid polarizer 211, and covers second surface 211b from the +Z side. Second surface 212b on the +Z side of base film 212 is located on the +Z side of second surface 101b of lens 101 at a distance corresponding to a substantially constant thickness along second surface 101b. Base film 212 is translucent to light in the visible wavelength band and is made of, for example, a flexible resin. The thickness of base film 212 in the Z direction is preferably approximately 50 μm to 200 μm.

[0023] By configuring the polarizing layer 111 using the wire grid polarizer 211, the polarizing layer 111 that exhibits the desired polarization characteristics can be easily formed on the second surface 101b, which is the curved surface of the lens 101, thereby minimizing the variation in the polarization characteristics exhibited by the polarizing layer 111 in the XY plane and increasing the uniformity of the polarization characteristics exhibited by the polarizing layer 111 in the XY plane.

[0024] On the other hand, for example, if the polarizing layer 111 is composed of a film-like polarizing element, when it is attached to the second surface 101b of the lens 101, the degree of stretching and stress of the film-like polarizing element will vary depending on the position in the XY plane and the radius of curvature of the second surface 101b, which may result in variations in the polarization characteristics exhibited by the polarizing layer 111 in the XY plane.

[0025] As described above, when the polarizing layer 111 is formed of the wire-grid polarizer 211, the polarizing layer 111 transmits linearly polarized light whose vibration direction is parallel to a direction perpendicular to the extension direction of the multiple wires that make up the wire-grid polarizer 211. In other words, when the polarizing layer 111 is formed of the wire-grid polarizer 211 and transmits only linearly polarized light whose vibration direction is parallel to the Y direction among the incident light, the multiple wires included in the polarizing layer 111 extend parallel to the X direction.

[0026] The quarter wavelength layer 121 is in contact with the second surface 111b of the polarizing layer 111 from the +Z side and is provided on the second surface 111b. The quarter wavelength layer 121 has a first surface 121a on the -Z side and a second surface 121b on the +Z side. The quarter wavelength layer 121 imparts a phase difference of a quarter wavelength to the incident light, and, for example, converts incident linearly polarized light into circularly polarized light and converts incident circularly polarized light into linearly polarized light.

[0027] The quarter-wave layer 121 is not limited to a specific type of element as long as it is a wavelength layer or a retardation layer that transmits only predetermined linearly polarized light as described above, but is preferably made of a birefringent material such as liquid crystal. The quarter-wave layer 121 has, for example, an alignment film 221, a sealing material 222, and a liquid crystal 224 that is a birefringent material.

[0028] The sealant 222 is disposed on the -Z side of the reflective layer 131, is provided on the first surface 221a of the reflective layer 131, and is interposed between the alignment film 221 and the reflective layer 131 in the Z direction to provide a certain distance from the first surface 131a of the reflective layer 131 to the -Z side. The sealant 222 is, for example, an annular member provided on the outer periphery of the reflective layer 131 centered on an axis JX parallel to the Z direction, and made of a resin or the like that is translucent to image light incident on the quarter-wave layer 121. Note that the sealant 222 may be, for example, a plurality of bead-shaped fine particles made of resin, and may be scattered on the first surface 221a of the alignment film 221.

[0029] The liquid crystal 224 is filled in the area surrounded by the alignment film 221, the sealing material 222, and the reflective layer 131, and is oriented along the light distribution direction of the alignment film 221. The layer filled with the liquid crystal 224 has a uniform thickness in the Z direction, which is equivalent to the thickness of the sealing material 222, along the second surface 101b of the lens 101, the first surface 102a of the lens 102, and the second surface 221b on the +Z side of the alignment film 221.

[0030] The alignment film 221 is provided along the second surface 101b of the lens 101 and the first surface 102a of the lens 102, specifically, on the -Z side surface of the sealing material 222 so as to cover the liquid crystal 224 from the -Z side. The alignment film 221 is translucent to the image light incident on the quarter wavelength layer 121. The alignment film 221 has a light distribution direction according to the phase difference imparted to the light incident on the quarter wavelength layer 121. The alignment film 221 may have, for example, a groove structure or the like formed along the light distribution direction.

[0031] By making the quarter-wave layer 121 from a birefringent material, the quarter-wave layer 121 that exhibits the desired phase difference-imparting characteristics can be easily formed on the second surface 111b of the polarizing layer 111 that is along the second surface 101b of the lens 101, the variation in the phase difference-imparting characteristics exhibited by the quarter-wave layer 121 in the XY plane is minimized, and the uniformity of the phase difference-imparting characteristics exhibited by the quarter-wave layer 121 in the XY plane is increased.

[0032] On the other hand, for example, if the quarter-wave layer 121 is composed of a film-like wavelength element or a phase difference element, when it is attached to the second surface 111b of the polarizing layer 111, the degree of stretching of the film-like polarizing element will vary depending on its position in the XY plane and the radius of curvature of the second surface 111b, and this may result in variations in the polarization characteristics exhibited by the polarizing layer 111 in the XY plane.

[0033] The reflective layer 131 contacts the second surface 121b of the quarter-wave layer 121 from the +Z side. Specifically, the reflective layer 131 is formed by vapor deposition or the like on a first surface 241a on the -Z side of the alignment film 241 of the quarter-wave layer 141. The reflective layer 131 has a first surface 131a on the -Z side and a second surface 131b on the +Z side. The reflective layer 131 transmits approximately half of the incident light and reflects the remaining approximately half, making it a so-called half mirror. The reflective layer 131 is not limited to a specific type of element as long as it transmits and reflects approximately half of the incident light as described above, but may be, for example, a metal vapor deposition film, a metal thin film, or a dielectric multilayer film. The thickness of the reflective layer 131 is, for example, 15 μm or less.

[0034] The quarter wavelength layer 141 is in contact with the second surface 131b of the reflective layer 131 from the +Z side and is provided on the second surface 131b. The quarter wavelength layer 141 has a first surface 141a on the -Z side and a second surface 141b on the +Z side. The quarter wavelength layer 141 imparts a phase difference of a quarter wavelength to incident light, and, for example, converts incident linearly polarized light into circularly polarized light and converts incident circularly polarized light into linearly polarized light.

[0035] The quarter-wave layer 141 is not limited to a specific type of element as long as it is a wavelength layer or a retardation layer that transmits only predetermined linearly polarized light as described above, but is preferably made of a birefringent material such as liquid crystal. The quarter-wave layer 141 has, for example, an alignment film 241, a sealing material 242, and a liquid crystal 244 that is a birefringent material.

[0036] The sealant 242 is disposed on the -Z side of the lens 102 and is provided on the first surface 102a of the lens 102. The sealant 242 is, for example, an annular member provided on the outer periphery of the lens 102 centered on the axis JX and made of a resin or the like that is translucent to image light incident on the quarter-wave layer 141. The sealant 242 may be, for example, a plurality of bead-shaped fine particles made of resin, which may be scattered on the first surface 241a of the alignment film 241. The sealant 242 is disposed on the +Z side of the alignment film 241 and is interposed between the alignment film 241 and the lens 102 in the Z direction to provide a certain distance from the first surface 102a of the lens 102 to the -Z side.

[0037] The liquid crystal 244 is filled in the area surrounded by the alignment film 241, the sealing material 242, and the lens 102, and is oriented along the light distribution direction of the alignment film 241. The layer filled with the liquid crystal 244 has a uniform thickness in the Z direction along the first surface 102a of the lens 102 and the second surface 241b of the alignment film 241, which is equivalent to the thickness of the sealing material 242.

[0038] The alignment film 241 is provided on the -Z side surface of the sealing material 242 along the first surface 102a of the lens 102, and is in contact with the -Z side surface of the liquid crystal 244. The alignment film 241 is translucent to image light incident on the quarter wavelength layer 141. The alignment film 241 has a light distribution direction according to a phase difference imparted to light incident on the quarter wavelength layer 141. The alignment film 241 may have, for example, a groove structure or the like formed along the light distribution direction.

[0039] By forming the quarter-wave layer 141 from a birefringent material, the quarter-wave layer 141 that exhibits the desired phase difference imparting characteristics can be easily formed on the second surface 131b of the reflective layer 131 or the second surface 102b of the lens 102, the variation in the phase difference imparting characteristics exhibited by the quarter-wave layer 141 in the XY plane can be minimized, and the uniformity of the phase difference imparting characteristics exhibited by the quarter-wave layer 141 in the XY plane can be increased.

[0040] When the quarter-wave layer 141 is made of a birefringent material, the birefringent material is applied to the second surface 131b of the reflective layer 131, for example, using a spray nozzle (not shown), similar to the quarter-wave layer 121. Specifically, the birefringent material is mixed with a solvent to form a coating liquid. After the coating liquid is applied to the second surface 131b of the reflective layer 131, the solvent is removed. At this time, the birefringent material is uniformly stacked with a substantially constant thickness on the second surface 131b of the reflective layer 131. Thereafter, the birefringent material is irradiated with electromagnetic waves such as ultraviolet light to align the orientation of the birefringent material in a predetermined direction, thereby performing orientation control. The predetermined direction is, for example, a direction that forms 45 degrees with respect to each of the X direction and the Y direction and is perpendicular to the Z direction.

[0041] When controlling and fixing the orientation of the birefringent material, methods other than the method of irradiating ultraviolet light as described above may be used, for example, by slowly removing the solvent depending on the speed of alignment of the liquid crystal molecules, or by using a cathodic liquid crystal composition as the birefringent material and photo-curing the composition while it is in a liquid crystal phase state.

[0042] Quarter-wave layers, including the quarter-wave layer 141, may be formed and fabricated as described below. For example, a photo-crosslinkable polymer liquid crystal material is applied to a substrate made of a flexible transparent resin that minimizes variations in transmission and polarization characteristics due to stretching or bending, to form a photo-crosslinkable polymer liquid crystal material layer, i.e., a thin film made of a photo-crosslinkable polymer liquid crystal material. The thin film of photo-crosslinkable polymer liquid crystal material is cured by irradiating it with linearly polarized ultraviolet light with a controlled polarization direction, thereby controlling the orientation of molecular species exhibiting liquid crystallinity. During this process, the ultraviolet light crosslinks molecular species that exhibit liquid crystallinity in a direction that matches the polarization direction of the ultraviolet light, thereby fixing their orientation in the same direction as the polarization direction. The thin film is then annealed to liquid crystallize molecular species exhibiting liquid crystallinity whose orientation was not changed by the ultraviolet light irradiation, thereby aligning the orientation of these molecular species with the polymer portion already in the desired orientation. As a result, the orientation is fixed. In other words, a wavelength layer made of a thin film in which the orientation directions of most of the molecular species exhibiting liquid crystallinity that make up the photo-crosslinkable polymer liquid crystal material are aligned is obtained. In such a wavelength layer, the retardation can be adjusted by adjusting the thickness.

[0043] The lens 102 corresponds to a second lens. The lens 102 is disposed on the +Z side of the lens 101 and on the −Z side of the viewer's eye EY, and is disposed on the optical path of the image light L1 emitted from the reflective layer 131 to the +Z side.

[0044] The lens 102 has a first surface 102a on the -Z side and a second surface 102b on the +Z side. The first surface 102a and the second surface 102b are curved surfaces that protrude toward the display element 50 in the Z direction, and are, for example, aspherical surfaces that protrude toward the -Z side. The lens 102 is, for example, a positive meniscus lens with a convex curved surface on the -Z side. The lens 102 focuses light incident from the -Z side toward the center of the XY plane and toward the eye EY on the +Z side.

[0045] The refractive index of the lens 102 is approximately 0.1 to 0.2 lower than the refractive index of the lens 101. This makes it easy to configure a telecentric optical system including the lenses 101 and 102. The lens 102 is formed from a material that is translucent to image light in the visible wavelength band, for example, a resin such as plastic. An example of the resin material for the lens 102 is APEL (registered trademark, manufactured by Mitsui Chemicals, Inc.), which is a low birefringence material with a high refractive index. A non-reflective coating (not shown) is applied to the second surface 102b of the lens 102, or an anti-reflection film (not shown) is provided thereon.

[0046] The radius of curvature of the first surface 102a of the lens 102 is equal to the radius of curvature of the second surface 101b of the lens 101. The radius of curvature of the second surface 102b is larger than the radius of curvature of the first surface 102a. The shape and radius of curvature of the first surface 102a and the shape and radius of curvature of the second surface 102b are appropriately set based on the results of a simulation using ray tracing that takes into account the paths of light rays in the virtual image display device 11, which will be described later, and depending on the size of the display surface 50p of the display element 50 in the X and Y directions, the distance between the display element 50 and the viewer's eye EY in the Z direction, and the refractive index of each component of the virtual image display device 11.

[0047] The quarter wavelength layer 141 may be in contact with the reflective layer 131 from the +Z side.

[0048] The polarizing layer 151 is in contact with the second surface 102b of the lens 102 from the +Z side and is provided on the second surface 102b. The polarizing layer 151 has a first surface 151a on the -Z side and a second surface 151b on the +Z side. The polarizing layer 151 transmits only a predetermined linearly polarized light of the incident light and reflects the remaining light other than the predetermined linearly polarized light. The predetermined polarized light is, for example, linearly polarized light vibrating in a direction parallel to the Y direction.

[0049] Polarizing layer 151 is not limited to a specific type of element as long as it is a polarizing layer that transmits only predetermined linearly polarized light and reflects the remaining light other than the predetermined linearly polarized light, as described above, but is preferably composed of a wire grid polarizer. By using a wire grid polarizer for polarizing layer 151, polarizing layer 151 that exhibits desired polarization characteristics can be easily formed on second surface 102b, which is the curved surface of lens 102, minimizing variation in the polarization characteristics exhibited by polarizing layer 151 in the XY plane and increasing the uniformity of the polarization characteristics exhibited by polarizing layer 151 in the XY plane.

[0050] Polarizing layer 151 has wire-grid polarizer 251 and base film 252. Wire-grid polarizer 251 is in contact with second surface 102b on the +Z side of lens 102, is provided on second surface 102b, and has a substantially constant thickness along second surface 102b. The thickness of wire-grid polarizer 251, i.e., the thickness of the multiple wires of wire-grid polarizer 251, is 1 μm or less, and specifically, is about several hundred nm.

[0051] Base film 252 is in contact with second surface 251b, which is the curved surface on the +Z side of wire-grid polarizer 251, and covers second surface 251b from the +Z side. Second surface 252b on the +Z side of base film 252 is located on the +Z side of second surface 102b of lens 102 at a distance corresponding to a substantially constant thickness along second surface 102b. Base film 252 is translucent to light in the visible wavelength band and is made of, for example, a flexible resin. The thickness of base film 252 in the Z direction is preferably approximately 50 μm to 200 μm.

[0052] As described above, when the polarizing layer 151 is made up of the wire grid polarizer 251, the polarizing layer 151 transmits linearly polarized light whose vibration direction is parallel to a direction perpendicular to the extension direction of the multiple wires that make up the wire grid polarizer 251. In other words, when the polarizing layer 151 is made up of the wire grid polarizer 251 and transmits only linearly polarized light whose vibration direction is parallel to the Y direction among the incident light, the multiple wires included in the polarizing layer 151 extend parallel to the X direction.

[0053] 3 is a diagram for explaining the path of image light in the virtual image display device 11 of the first embodiment. In FIG. 3, in order to clearly show the polarization of the image light, the components are separated in the Z direction with intervals between them.

[0054] As shown in FIG. 3, image light L1 emitted from the display surface 50p of the display element 50 travels toward the +Z side, is refracted by the first surface 101a of the lens 101, and approaches an axis JX passing through the center of the display element 50 in the X and Y directions in the XY plane. The image light L1 incident on the lens 101 from the first surface 101a is refracted again by the second surface 101b, emitted from the lens 101, and incident on the polarizing layer 111. Of the image light L1 incident on the polarizing layer 111, image light L2, which is linearly polarized light whose polarization direction is parallel to the Y direction, passes through the polarizing layer 111 and is emitted toward the +Z side. Of the image light L1 incident on the polarizing layer 111, linearly polarized light whose polarization direction is not parallel to the Y direction, i.e., light other than the image light L2, is reflected by the polarizing layer 111 and emitted toward the -Z side or absorbed by the polarizing layer 111.

[0055] The image light L2 emitted from the polarizing layer 111 to the +Z side is incident on the quarter-wave layer 121 and converted by the quarter-wave layer 121 into circularly polarized image light L3. The image light L3 is clockwise or counterclockwise circularly polarized light, for example, clockwise circularly polarized light. The image light L3 is emitted from the quarter-wave layer 121 to the +Z side and incident on the reflective layer 131. Image light L31, which has about half the amount of light of the image light L3 incident on the reflective layer 131, passes through the reflective layer 131 and is emitted to the +Z side. The remaining image light L32, which has about half the amount of light of the image light L3 incident on the reflective layer 131, is reflected by the reflective layer 131 and is emitted to the -Z side.

[0056] The image light L31 emitted from the reflective layer 131 to the +Z side is incident on the quarter wavelength layer 141 and converted into linearly polarized image light L4 by the quarter wavelength layer 141. The polarization direction of the image light L4 is parallel to the X direction and orthogonal to the Y direction. The image light L4 is emitted from the quarter wavelength layer 141 to the +Z side and enters the lens 102.

[0057] Image light L4 incident on lens 102 is refracted by first surface 102a of lens 102, moves closer to axis JX in the XY plane, and reaches second surface 102b of lens 102. Image light L4 reaching second surface 102b of lens 102 reaches first surface 151a that is in contact with second surface 102b, but because its polarization direction is orthogonal to the Y direction, it is reflected by first surface 151a and emitted to the -Z side, and then emitted as image light L5 in a direction away from axis JX in the XY plane.

[0058] The image light L5 emitted from the lens 102 to the -Z side is incident on the quarter-wave layer 141, converted by the quarter-wave layer 141 into image light L6, which is right-handed circularly polarized light, and emitted from the quarter-wave layer 141 to the -Z side. The image light L6 emitted from the quarter-wave layer 141 to the -Z side is incident on the reflective layer 131. Image light L61, which has about half the amount of light of the image light L6 incident on the reflective layer 131, passes through the reflective layer 131 and is emitted to the -Z side. The image light L61 is right-handed circularly polarized light, just like the image light L6 incident on the reflective layer 131 from the +Z side. The remaining image light L62, which has about half the amount of light of the image light L6 incident on the reflective layer 131, is reflected by the reflective layer 131 and emitted to the +Z side. The image light L62 is reflected by the reflective layer 131 and converted into left-handed circularly polarized light, which is the opposite rotation to the image light L6 incident on the reflective layer 131 from the +Z side.

[0059] The image light L62 emitted from the reflective layer 131 to the +Z side is incident on the quarter-wave layer 141, converted by the quarter-wave layer 141 into linearly polarized image light L7, and emitted from the quarter-wave layer 141 to the +Z side. The polarization direction of the image light L7 is parallel to the Y direction. The image light L7 emitted from the quarter-wave layer 141 to the +Z side passes through the lens 102, and while being emitted to the +Z side, is moved closer to the axis JX in the XY plane by the lens 102. The image light L7 emitted from the lens 102 to the +Z side passes through the polarizing layer 151, is emitted to the +Z side, and reaches a predetermined imaging position that is on the +Z side of the polarizing layer 151 and on the +Z side of the viewer's eye EY.

[0060] Image light L61 emitted from the reflective layer 131 to the -Z side is incident on the quarter-wave layer 121 and converted into linearly polarized image light L8 by the quarter-wave layer 121. The polarization direction of the image light L8 is parallel to the Y direction. The image light L8 passes through the polarizing layer 111 along the Z direction and returns to the display element 50 from the -Z side.

[0061] As a result of the image light L1 emitted from multiple pixels on the display surface 50p of the display element 50 propagating as described above, the image light L7 is focused at a predetermined imaging position, forming a virtual image. The viewer views the virtual image from the +Z side. In the virtual image display device 11, the image light L5 emitted from at least the outer periphery of the XY plane of the polarizing layer 151 to the -Z side is reflected more toward the outer periphery than the image light L4 incident on the outer periphery of the polarizing layer 151 from the -Z side. This allows the viewer to view the virtual image at a wide viewing angle. The virtual image display device 11 achieves excellent imaging characteristics at a wide viewing angle.

[0062] The virtual image display device 11 of the first embodiment described above includes a display element 50, a lens (first lens) 101, a lens (second lens) 102, a polarizing layer (first polarizing layer) 151, a polarizing layer (second polarizing layer) 111, a quarter-wave layer (first wavelength layer) 121, a reflective layer 131, and a quarter-wave layer (second wavelength layer) 141. The display element 50 emits image light L1 toward the +Z side (first side) along the Z direction (first direction). The lens 101 is disposed on the +Z side of the display element 50 and includes a first surface (curved surface) 101a and a second surface (curved surface) 101b that protrude toward the display element 50. The lens 102 is disposed on the +Z side of the lens 101 and includes a first surface (curved surface) 102a and a second surface (curved surface) 102b that protrude toward the display element 50. The radius of curvature of second surface (curved surface on the first side) 102b on the +Z side of lens 102 is larger than the radius of curvature of first surface (curved surface on the second side) 102a on the -Z side opposite to the +Z side in the Z direction. Polarizing layer 151 is disposed further on the +Z side than lens 102 and is disposed closer to the viewer's eye EY than other components of virtual image display device 11. Polarizing layer 151 is formed along second surface 102b on the +Z side of lens 102. Polarizing layer 151 transmits linearly polarized light (first polarized light) having a polarization direction parallel to the Y direction out of incident light including image light (light) L4, and reflects polarized light other than linearly polarized light having a polarization direction parallel to the Y direction out of incident light (second polarized light) to the -Z side in the Z direction (second side opposite to the first side). The polarizing layer 111 is disposed between the display element 50 and the lens 102 in the Z direction, is formed along the second surface 101b of the lens 101 and the first surface 101a of the lens 102, and transmits linearly polarized light having a polarization direction parallel to the Y direction out of the incident light. The quarter-wave layer 121 is disposed between the polarizing layer 111 and the lens 102 in the Z direction, and is formed along the second surface (curved surface on the first side) 101b of the lens 101 and the first surface 101a of the lens 102, and transmits the incident light by imparting a phase difference equivalent to one-quarter of the wavelength of the light. The reflective layer 131 is disposed between the quarter-wave layer 121 and the lens 102 in the Z direction, and is formed along the second surface (curved surface on the first side) 101b of the lens 101 and the first surface 101a of the lens 102, and transmits a portion of the incident light and reflects the remainder of the incident light.The quarter-wave layer 141 is disposed between the reflective layer 131 and the lens 102 in the Z direction, and is formed along the second surface 101b of the lens 101 and the first surface 101a of the lens 102, and transmits the incident light by imparting a phase difference equivalent to 1 / 4 of the wavelength of the light to the incident light.

[0063] In the virtual image display device 11 of the first embodiment, the lenses 101 and 102 are configured with curved surfaces that protrude toward the display element 50 in the Z direction, and the polarizing layer 111, the quarter-wave layer 121, the reflective layer 131, the quarter-wave layer 141, and the polarizing layer 151 are formed along the second surface 101b of the lens 101 and the second surface 102b of the lens 102, respectively, and can be designed based on the ray tracing method of geometric optics. Therefore, the virtual image display device 11 of the first embodiment is easy to miniaturize and manufacture. Furthermore, in the virtual image display device 11 of the first embodiment, the radius of curvature of the second surface 102b of the lens 102 is larger than the radius of curvature of the first surface 102a, and the curvature of the second surface 102b is smaller than the curvature of the first surface 102a. The term "curvature" refers to the reciprocal of the radius of curvature. Therefore, the image light propagates in a folded manner in the Z direction, and a virtual image is formed at a predetermined imaging position after the image light including the image light L5 is folded back radially outward with respect to the axis JX by the polarizing layer 151. Therefore, the virtual image display device 11 of the first embodiment exhibits excellent optical characteristics over a wide viewing angle.

[0064] In the virtual image display device 11 of the first embodiment, quarter-wave layers 121 and 141, which are disposed between the lenses 101 and 102 in the Z direction in which image light including image light L1 to L7 propagates, are formed along the second surface 101b of the lens 101 and the first surface 102a of the lens 102. Specifically, in the virtual image display device 11 of the first embodiment, the quarter-wave layers 121 and 141 do not use retardation films disposed on the surface of a flat substrate or a planar wave plate as in the past. Instead, the material of the quarter-wave layers 121 and 141 is formed along the second surface 101b and the first surface 102a, so that no phase distortion occurs on the second surface 101b and the first surface 102a. Therefore, the virtual image display device 11 of the first embodiment exhibits excellent optical characteristics over a wide viewing angle, obtains a sufficient amount of image light that is focused toward the viewer's eye EY, and improves the visibility of the virtual image. In the virtual image display device 11 of the first embodiment, a viewing angle exceeding 100 degrees can be achieved using a relatively small display element 50 of, for example, 1.5 inches or less.

[0065] In the virtual image display device 11 of the first embodiment, the refractive index of the lens 102 is lower than the refractive index of the lens 101.

[0066] According to the virtual image display device 11 of the first embodiment, image light incident on the lens 102 from the -Z side is efficiently totally reflected and emitted radially outward relative to the axis JX, thereby making it possible to make the entire device thinner and widen the viewing angle.

[0067] In the virtual image display device 11 of the first embodiment, a polarizing layer 111, a quarter wavelength layer 121, a reflective layer 131, and a quarter wavelength layer 141 are sequentially arranged in the Z direction from the −Z side to the +Z side between the lens 101 and the lens 102. The polarizing layer 111, the quarter wavelength layer 121, the reflective layer 131, and the quarter wavelength layer 141 are stacked between the lenses 101 and 102.

[0068] According to the virtual image display device 11 of the first embodiment, a thin folded optical system with a reduced size in the Z direction is constructed as described above, which achieves both excellent optical properties and telecentricity over a wide viewing angle, thereby producing a highly visible virtual image.

[0069] In the virtual image display device 11 of the first embodiment, the quarter-wave layer 121 has an alignment film (first alignment film) 221, a sealant 222, and a liquid crystal 224 that is a birefringent material. The alignment film 221 is provided along a first surface 102a on the -Z side of the lens 102. The sealant 222 is disposed on the -Z side of the alignment film 221 and is interposed to provide a certain distance from a second surface 221b on the +Z side of the alignment film 221 to the -Z side. The liquid crystal 224 is filled in a region surrounded by the alignment film 221, the sealant 222, and the reflective layer 131, and is oriented along the light distribution direction of the alignment film 221.

[0070] According to the virtual image display device 11 of the first embodiment, a quarter-wave layer 121 that uniformly imparts a phase difference equivalent to one-quarter of the wavelength to the image light L3 and does not cause phase disturbance can be provided along the first surface 102a, which is the curved surface of the lens 102, specifically along the first surface 131a of the reflective layer 131. As a result, the virtual image display device 11 of the first embodiment can achieve excellent optical characteristics over a wide viewing angle.

[0071] In the virtual image display device 11 of the first embodiment, the quarter-wave layer 141 is configured similarly to the quarter-wave layer 121 and includes an alignment film (second alignment film) 241, a sealant 242, and a liquid crystal 244 that is a birefringent material. The alignment film 241 is provided along a first surface 102a on the -Z side of the lens 102. The sealant 242 is disposed on the +Z side of the alignment film 241 and is interposed to provide a certain distance from a second surface 241b on the +Z side of the alignment film 241 to the +Z side. The liquid crystal 244 is filled in a region surrounded by the alignment film 241, the sealant 242, and the reflective layer 131, and is oriented along the light distribution direction of the alignment film 241.

[0072] According to the virtual image display device 11 of the first embodiment, a quarter-wave layer 141 that uniformly imparts a phase difference equivalent to a quarter of the wavelength to the image light beams L31, L5, L62, etc. and does not cause phase disturbance can be provided along the second surface 101b of the lens 101, specifically along the first surface 102a of the lens 102. As a result, the virtual image display device 11 of the first embodiment can achieve excellent optical characteristics over a wide viewing angle.

[0073] In the virtual image display device 11 of the first embodiment, the polarizing layer 111 has a wire grid polarizer (second wire grid polarizer) 211 provided on the second surface 101b of the lens 101, and a base film (second base film) 212 covering the wire grid polarizer 211 from the +Z side.

[0074] According to the virtual image display device 11 of the first embodiment, a polarizing layer 111 that emits only predetermined linearly polarized light from the image light L31, L5, L62, etc. and does not cause variations in polarization characteristics can be provided along the second surface 101b of the lens 101. As a result, the virtual image display device 11 of the first embodiment can obtain excellent optical characteristics over a wide viewing angle.

[0075] In the virtual image display device 11 of the first embodiment, the polarizing layer 151 has a wire grid polarizer (first wire grid polarizer) 251 provided on the second surface 102b of the lens 102, and a base film (first base film) 252 covering the wire grid polarizer 251 from the +Z side.

[0076] According to the virtual image display device 11 of the first embodiment, a polarizing layer 151 that emits only predetermined linearly polarized light from the image light L4, L7, etc. and does not cause variations in polarization characteristics can be provided along the second surface 102b of the lens 102. As a result, the virtual image display device 11 of the first embodiment can achieve excellent optical characteristics over a wide viewing angle.

[0077] In the virtual image display device 11 of the first embodiment, the polarizing layer 151 is formed on the second surface 102b of the lens 102 and is in contact with the second surface 102b.

[0078] According to the virtual image display device 11 of the first embodiment, it is possible to reduce the size in the Z direction, that is, to reduce the thickness. Furthermore, according to the virtual image display device 11 of the first embodiment, the polarization state of the image light including the image light beams L4 and L7 emitted from the lens 102 and incident on the polarizing layer 151 is not disturbed before it is incident on the polarizing layer 151, and the polarization state of the image light is made to act as desired, thereby obtaining excellent optical characteristics.

[0079] In the virtual image display device 11 of the first embodiment, the quarter-wave layer 141 is formed on the first surface 102a of the lens 102, which has a radius of curvature equal to that of the second surface 101b, along the second surface 101b of the lens 101, and is in contact with the first surface 102a.

[0080] According to the virtual image display device 11 of the first embodiment, it is possible to reduce the size in the Z direction, that is, to reduce the thickness. Furthermore, according to the virtual image display device 11 of the first embodiment, the phase of the image light including the image light beams L31, L5, and L62 is not significantly changed before it is incident on the quarter-wave layer 141, and a desired phase difference is imparted to the phase of the image light, thereby obtaining excellent optical characteristics.

[0081] In the virtual image display device 11 of the first embodiment, the display element 50, the lens 101, the polarizing layer 111, the quarter-wave layer 121, the reflective layer 131, the quarter-wave layer 141, the lens 102, and the polarizing layer 151 are sequentially arranged from the -Z side to the +Z side, and adjacent components in the Z direction are in contact with each other. This allows the virtual image display device 11 of the first embodiment to be miniaturized in the Z direction, i.e., the entire device to be made thinner. Furthermore, as described above, because adjacent components in the Z direction of the virtual image display device 11 of the first embodiment, i.e., devices or layers, are in contact with each other, the optical effect of each layer on the image light can be more accurately imparted, resulting in the desired excellent optical characteristics and a clear virtual image.

[0082] [Second embodiment] Next, a second embodiment of the present invention will be described with reference to FIG. 4. Regarding the virtual image display device of each of the following embodiments, only the configurations that are different from the virtual image display device 11 of the first embodiment will be described. Among the components of the virtual image display device of each embodiment, components that are common to the virtual image display device 11 of the first embodiment are assigned the same reference numerals as the corresponding components of the virtual image display device 11 of the first embodiment. Description of the components that are common to the virtual image display device 11 of the first embodiment will be omitted.

[0083] Fig. 4 is a schematic diagram of a virtual image display device 12 of a second embodiment. As shown in Fig. 4, the virtual image display device 12, like the virtual image display device 11, includes a display element 50, a lens 101, a polarizing layer 111, a quarter-wave layer 121, a reflective layer 131, a lens 102, a quarter-wave layer 141, and a polarizing layer 151. In the virtual image display device 12, the quarter-wave layer 141 is disposed between the lens 102 and the polarizing layer 151 in the Z direction.

[0084] The quarter-wave layer 141 is made of a birefringent material. In the virtual image display device 12, as an example, a birefringent material is applied to the second surface 111b of the polarizing layer 111 using a spray nozzle (not shown). Specifically, the birefringent material is mixed with a solvent to form a coating liquid. After the coating liquid is applied to the second surface 111b of the polarizing layer 111, the solvent is removed. At this time, the birefringent material is uniformly stacked with a substantially constant thickness on the second surface 111b of the polarizing layer 111. Thereafter, the birefringent material is irradiated with electromagnetic waves such as ultraviolet rays to align the orientation of the birefringent material in a predetermined direction, thereby performing orientation control. The predetermined direction is, for example, a direction that forms 45 degrees with respect to each of the X direction and the Y direction and is perpendicular to the Z direction.

[0085] The virtual image display device 12 of the second embodiment described above provides the same effects as those of the configuration common to the virtual image display device 11 of the first embodiment.

[0086] In the virtual image display device 12 of the second embodiment, a polarizing layer 111, a quarter wavelength layer 121, and a reflective layer 131 are sequentially arranged toward the first side between the lens 101 and the lens 102 in the Z direction. In the virtual image display device 12 of the second embodiment, a quarter wavelength layer 141 is arranged between the lens 102 and the polarizing layer 151 in the Z direction.

[0087] According to the virtual image display device 12 of the second embodiment, similar to the virtual image display device 11 of the first embodiment, a thin folded optical system with a reduced size in the Z direction is constructed, which achieves both excellent optical properties and telecentricity over a wide viewing angle, thereby producing a highly visible virtual image.

[0088] Furthermore, in the virtual image display device 12 of the second embodiment, a coating liquid containing a birefringent material is applied to a uniform thickness on the second surface 102b of the lens 102, which is concave when viewed from the +Z side, and is oriented in a predetermined light distribution direction. This makes it possible to provide a quarter-wave layer 141 along the second surface 102b of the lens 102, which uniformly imparts a phase difference equivalent to a quarter of the wavelength to the image light beams L31, L5, L62, etc., and does not cause phase disturbance. As a result, the virtual image display device 12 of the second embodiment also achieves excellent optical characteristics over a wide viewing angle.

[0089] Here, an example of the design of the virtual image display device 12 of the second embodiment will be described. The size of the display surface 50p of the display element 50 in the X and Y directions is 1.0 to 1.5 inches, specifically 1.1 inches. The distance in the Z direction from the display surface 50p of the display element 50 to the vertex of the first surface 102a of the lens 102 is 17 mm, specifically 16 mm. The distance in the Z direction from the display surface 50p of the display element 50 to a predetermined imaging position of the image light is 23 mm or less, specifically 22 mm. The maximum thickness in the Z direction of the lens 102, i.e., the thickness on the axis JX of the lens 102, is 12 mm or less, specifically 11 mm.

[0090] The resin material of lens 101 is OKP-1, and the resin material of lens 102 is APEL, specifically APEL5514. The refractive index of OKP-1 that constitutes lens 101 is 1.669656 at a wavelength of 465 nm, 1.654206 at a wavelength of 520 nm, and 1.638017 at a wavelength of 620 nm. The refractive index of APEL5514 that constitutes lens 102 is 1.552944 at a wavelength of 465 nm, 1.548179 at a wavelength of 520 nm, and 1.542599 at a wavelength of 620 nm.

[0091] By applying the above-described design and conditions to the configuration of the virtual image display device 12, a field of view (FOV) of 100 degrees or more can be obtained, specifically a field of view of 120 degrees. Furthermore, by applying the above-described design and conditions to the configuration of the virtual image display device 12, the widest field of view at which telecentricity can be obtained is 10 degrees or less, specifically 7 degrees or less.

[0092] Table 1 shows an example of surface data for the first surface 101a and second surface 101b of the lens 101, and the first surface 102a and second surface 102b of the lens 102.

[0093] [Table 1]

[0094] The aspherical coefficients of each surface in Table 1 are the coefficients A4, A6, A8, and A9 in the following equation (1). 10 In equation (1), R represents the radius of curvature. In equation (1), K represents the Conic coefficient.

[0095]

number

[0096] [Third embodiment] Next, a third embodiment of the present invention will be described with reference to Fig. 5. Fig. 5 is a schematic diagram of a virtual image display device 13 of the third embodiment. As shown in Fig. 5, the virtual image display device 13 includes a display element 60, a lens 101, a polarizing layer 111, a quarter-wave layer 121, a reflective layer 131, a quarter-wave layer 141, a lens 102, and a polarizing layer 151.

[0097] The display element 60, like the display element 50, displays an image or video of an object visually recognized by an observer and emits image light. The display element 60 is, for example, a liquid crystal display, is connected to a terminal device or image generating device (not shown) by wire or wirelessly, and emits image light in accordance with image information received from the terminal device or image generating device. The terminal device or image generating device is, for example, a smartphone, a tablet terminal device, or a computer.

[0098] The display element 60 has a display surface 60p that emits the image light L1. A plurality of pixels (not shown) are provided along the X direction and the Y direction on the display surface 60p of the display element 60. That is, a plurality of pixels are two-dimensionally arranged on the display surface 60p.

[0099] In the virtual image display device 13, the polarizing layer 111 is disposed between the display element 60 and the lens 101 in the Z direction, specifically disposed immediately on the +Z side of the display element 60, and is in contact with the display element 60. That is, the first surface 111a of the polarizing layer 111 is in contact with the display surface 60p of the display element 60. The first surface 111a and the second surface 111b of the polarizing layer 111 are flat surfaces that are perpendicular to the axis JX and parallel to the display surface 60p of the display element 60.

[0100] The polarizing layer 111 of the virtual image display device 13 may be a wire grid polarizer 211, an absorption polarizing plate, or a polarizing element attached to a liquid crystal display or a liquid crystal panel. Note that an appropriate gap may be provided between the display element 60 and the polarizing layer 111 in the Z direction.

[0101] The virtual image display device 12 of the second embodiment described above provides the same effects as those of the configuration common to the virtual image display device 11 of the first embodiment.

[0102] In the virtual image display device 13 of the third embodiment, a polarizing layer 111 is disposed between the display element 60 and the lens 101 in the Z direction. In the virtual image display device 13 of the third embodiment, a quarter-wave layer 121 and a reflective layer 131 are sequentially disposed between the lens 101 and the lens 102 in the Z direction toward the +Z side.

[0103] According to the virtual image display device 13 of the third embodiment, similar to the virtual image display device 11 of the first embodiment, a thin folded optical system with a reduced size in the Z direction is constructed, which achieves both excellent optical properties and telecentricity over a wide viewing angle, thereby producing a highly visible virtual image.

[0104] In the virtual image display device 13 of the third embodiment, the quarter wavelength layer 121 is formed on the second surface 101b of the lens 101 and is in contact with the second surface 101b.

[0105] According to the virtual image display device 13 of the third embodiment, it is possible to reduce the size in the Z direction, that is, to reduce the thickness. Furthermore, according to the virtual image display device 13 of the third embodiment, the phase of the image light including the image light L1 is not significantly changed before it is incident on the quarter wavelength layer 121, and a desired phase difference is imparted to the phase of the image light, thereby obtaining excellent optical characteristics.

[0106] [Other forms] In the virtual image display device of the present disclosure, the polarizing layer (first polarizing layer) 151 is formed along the second surface (first side surface) 102b of the lens 102. Specifically, the state of being formed along the second surface 102b specifically includes a state in which the polarizing layer is formed or applied directly on the second surface 102b of the lens 102, like the polarizing layer 151 in each of the above-described embodiments, and the surface has a radius of curvature equivalent to that of the second surface 102b, and further includes a state in which the polarizing layer is disposed close to the second surface 102b with a small gap therebetween so that the emission characteristics of the image light do not change in the Z direction, and the surface has a radius of curvature equivalent to that of the second surface 102b, or a state in which a thin layer structure that does not affect the polarization characteristics of the image light in the Z direction is interposed between the polarizing layer 151 and the second surface 102b, and the surface has a radius of curvature equivalent to that of the second surface 102b.

[0107] Similarly, in the virtual image display device of the present disclosure, quarter-wave layer (first-wave layer) 121 is formed along second surface 101b (first-side surface) 101b of lens 101. The state of being formed along second surface 101b specifically includes a state in which quarter-wave layer 121 is directly formed or applied on second surface 101b of lens 101, as in quarter-wave layer 121 of the third embodiment described above, and the surface has a radius of curvature equivalent to that of second surface 101b, and further includes a state in which quarter-wave layer 121 is disposed close to second surface 101b with a small gap therebetween so that the emission characteristics of image light do not change in the Z direction, and the surface has a radius of curvature equivalent to that of second surface 101b, or a state in which a thin layer structure such as polarizing layer 111 that does not affect the phase difference of image light in the Z direction is interposed between quarter-wave layer 121 and second embodiment described above, and the surface has a radius of curvature equivalent to that of second surface 101b.

[0108] Furthermore, in the virtual image display device of the present disclosure, the second reflective layer, or the reflective layer, may be formed on the first or second surface of the layer adjacent in the first direction as described in each of the above-mentioned embodiments, or may be arranged close to the layer adjacent in the first direction with a small gap therebetween, or a thin layer structure that does not affect the image light in unexpected optical properties may be interposed between the layers adjacent in the first direction.

[0109] Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention as described in the claims.

[0110] For example, the virtual image display devices of the above-described embodiments can be applied to head-mounted display devices such as head-mounted displays, and can also be appropriately applied to optical devices other than head-mounted display devices.

[0111] Summary of this disclosure A summary of this disclosure is provided below. (Supplementary Note 1) A display element that emits image light to a first side along a first direction, a first lens that is arranged on the first side of the display element and has a curved surface that protrudes toward the display element, a second lens that is arranged on the first side of the first lens and has a curved surface that protrudes toward the display element, the radius of curvature of the curved surface on the first side being larger than the radius of curvature of the curved surface on a second side opposite to the first side in the first direction, a first polarizing layer that is arranged on the first side of the second lens and is formed along the curved surface on the first side of the second lens, and transmits a first polarized light of incident light and reflects a second polarized light of incident light that is different from the first polarized light, and a second polarized light that is arranged between the display element and the second lens in the first direction and reflects the incident light. a first wavelength layer disposed between the second polarizing layer and the second lens in the first direction, formed along the curved surface of the first lens on the first side, and transmitting the incident light by giving the incident light a phase difference equivalent to ¼ of the wavelength of the light; a reflective layer disposed between the first wavelength layer and the second lens in the first direction, transmitting a portion of the incident light and reflecting the remainder of the incident light; and a second wavelength layer disposed between the reflective layer and the first polarizing layer in the first direction, formed along the curved surface of the first lens on the first side, and transmitting the incident light by giving the incident light a phase difference equivalent to ¼ of the wavelength of the light.

[0112] With the configuration of Supplementary Note 1, the virtual image display device is easy to miniaturize and manufacture, and exhibits excellent optical characteristics with good telecentricity and a wide viewing angle.

[0113] (Supplementary Note 2) The virtual image display device according to Supplementary Note 1, wherein the refractive index of the second lens is higher than the refractive index of the first lens.

[0114] The configuration of Supplementary Note 1 makes it possible to reduce the thickness of the entire device and widen the viewing angle.

[0115] (Appendix 3) A virtual image display device according to appendix 1 or appendix 2, wherein in the first direction, the second polarizing layer, the first wavelength layer, the reflective layer, and the second wavelength layer are sequentially arranged between the first lens and the second lens toward the first side.

[0116] The configuration of Supplementary Note 3 makes it possible to easily configure a thin telecentric optical system along the first direction, and obtain excellent optical characteristics over a wide viewing angle.

[0117] (Appendix 4) The virtual image display device of Appendix 3, wherein the first wavelength layer includes a first alignment film provided along the curved surface of the second side of the second lens, a sealant disposed on the second side of the first alignment film and interposed to leave a certain distance from the surface of the second side of the first alignment film to the second side, and a birefringent material filled in the space surrounded by the first alignment film and the sealant and oriented along the light distribution direction of the first alignment film.

[0118] The configuration of Supplementary Note 4 allows the first wavelength layer, which has less phase difference disturbance than a conventional film-type wavelength plate, to be arranged along the second-side curved surface of the second lens, which is a convex curved surface that protrudes toward the display element. As a result, excellent optical properties are obtained, and the visibility of the virtual image is improved.

[0119] (Appendix 5) The virtual image display device of Appendix 4, wherein the second wavelength layer includes a second alignment film provided along the curved surface of the second lens on the second side, a sealant disposed on the second side of the second alignment film and interposed to leave a fixed distance from the surface of the second alignment film on the second side to the second side, and a birefringent material filled in the area surrounded by the second alignment film and the sealant and oriented along the light distribution direction of the second alignment film.

[0120] The configuration of Supplementary Note 5 allows a second wavelength layer that causes less disturbance in phase difference than a conventional film-like wavelength plate, etc., to be arranged along the curved surface on the second side of the second lens. As a result, excellent optical properties are obtained, and the visibility of the virtual image is improved.

[0121] (Appendix 6) The virtual image display device of any one of Appendices 1 to 5, wherein the first polarizing layer includes a first wire-grid polarizer provided on the curved surface of the second lens on the first side, and a first substrate film covering the first wire-grid polarizer from the first side.

[0122] The configuration of Supplementary Note 6 allows the first modulation layer, which has smaller variations in polarization characteristics than conventional film-type polarization elements, to be arranged along the curved surface of the first side of the second lens that is recessed toward the display element. As a result, excellent optical characteristics are obtained, and the visibility of the virtual image is improved.

[0123] (Appendix 7) The virtual image display device of any one of Appendices 1 to 6, wherein the second polarizing layer includes a second wire-grid polarizer provided on the curved surface of the first lens on the first side, and a second substrate film covering the second wire-grid polarizer from the first side.

[0124] The configuration of Supplementary Note 7 allows the second modulation layer, which has less variation in polarization characteristics than conventional film-type polarization elements, to be arranged along the curved surface of the first side of the first lens that is recessed toward the display element. As a result, excellent optical characteristics are obtained, and the visibility of the virtual image is improved.

[0125] (Appendix 8) A virtual image display device according to Appendix 1 or Appendix 2, wherein in the first direction, the second polarizing layer, the first wavelength layer, and the reflective layer are sequentially arranged between the first lens and the second lens toward the first side, and the second wavelength layer is arranged between the second lens and the first polarizing layer in the first direction.

[0126] The configuration of Supplementary Note 8 makes it possible to easily configure a thin telecentric optical system along the first direction, and obtain excellent optical characteristics over a wide viewing angle.

[0127] (Appendix 9) A virtual image display device according to Appendix 1 or Appendix 2, wherein the second polarizing layer is arranged between the display element and the first lens in the first direction, and the first wavelength layer and the reflective layer are arranged sequentially between the first lens and the second lens in the first direction toward the first side.

[0128] According to the configuration of Supplementary Note 9, the second polarizing layer is disposed on the first side of the display element, and a thin telecentric optical system can be easily configured along the first direction, thereby achieving excellent optical characteristics at a wide viewing angle.

[0129] (Supplementary Note 10) The virtual image display device of Supplementary Note 1 or Supplementary Note 2, wherein the first polarizing layer is formed on the curved surface of the second lens on the first side and is in contact with the curved surface of the second lens on the first side.

[0130] The configuration of Supplementary Note 10 enables the virtual image display device to be further thinned. Also, the configuration of Supplementary Note 10 makes it difficult for the polarization state of the image light emitted from the second lens to be disturbed before it enters the first polarizing layer, thereby achieving excellent optical characteristics.

[0131] (Appendix 11) A virtual image display device according to Appendix 1 or Appendix 2, wherein the second wavelength layer is formed on the curved surface of the second lens that is aligned with the curved surface of the first lens on the first side and is in contact with the curved surface of the second lens on the second side.

[0132] The virtual image display device can be made even thinner by the configuration of Supplementary Note 11. In addition, the configuration of Supplementary Note 11 makes it difficult for the phase of the image light to be disturbed before it enters the second wavelength layer, thereby obtaining excellent optical characteristics.

[0133] (Appendix 12) The virtual image display device of Appendix 1 or Appendix 2, wherein the first wavelength layer is formed on the curved surface of the first lens on the first side and is in contact with the curved surface of the first lens on the first side.

[0134] With the configuration of Supplementary Note 12, the phase of the image light, including the image light emitted from the first lens, is less likely to be disturbed before it enters the first wavelength layer, and excellent optical characteristics can be obtained. [Explanation of symbols]

[0135] 11...virtual image display device, 50, 60...display element, 101...lens (first lens), 102...lens (second lens), 111...polarizing layer (second polarizing layer), 121...1 / 4 wavelength layer (first wavelength layer), 131...reflective layer, 141...1 / 4 wavelength layer (first wavelength layer), 151...polarizing layer (first polarizing layer).

Claims

1. a display element that emits image light to a first side along a first direction; a first lens disposed on the first side of the display element and having a curved surface protruding toward the display element; a second lens arranged on the first side of the first lens, having a curved surface protruding toward the display element, the second lens having a radius of curvature of the curved surface on the first side greater than the radius of curvature of the curved surface on a second side opposite to the first side in the first direction; a first polarizing layer that is disposed on the first side of the second lens, that is formed along the curved surface of the second lens on the first side, that transmits a first polarized light of incident light, and that reflects a second polarized light of incident light that is different from the first polarized light; a second polarizing layer disposed between the display element and the second lens in the first direction and transmitting a first polarized light of incident light; a first wavelength layer that is disposed between the second polarizing layer and the second lens in the first direction, that is formed along the curved surface of the first lens on the first side, and that transmits the incident light by giving the incident light a phase difference corresponding to ¼ of the wavelength of the light; a reflective layer disposed between the first-wavelength layer and the second lens in the first direction, the reflective layer transmitting a portion of incident light and reflecting the remainder of the incident light; a second wavelength layer that is disposed between the reflective layer and the first polarizing layer in the first direction, that is formed along the curved surface of the first lens on the first side, and that transmits the incident light by giving the incident light a phase difference corresponding to ¼ of the wavelength of the light; Equipped with Virtual image display device.

2. The refractive index of the second lens is lower than the refractive index of the first lens. The virtual image display device according to claim 1 .

3. the second polarizing layer, the first wavelength layer, the reflective layer, and the second wavelength layer are sequentially arranged between the first lens and the second lens toward the first side in the first direction; 3. The virtual image display device according to claim 1 or 2.

4. The first wavelength layer is a first alignment film provided along the curved surface of the second lens on the second side; a sealant disposed on the second side of the first alignment film to provide a predetermined distance from the surface of the second side of the first alignment film to the second side; a birefringent material filled in a space surrounded by the first alignment film and the sealing material and oriented along the light distribution direction of the first alignment film; having The virtual image display device according to claim 3 .

5. The second wavelength layer is a second alignment film provided along the curved surface of the second lens on the second side; a sealant disposed on the second side of the second alignment film to provide a predetermined distance from the surface of the second side of the second alignment film to the second side; a birefringent material filled in an area surrounded by the second alignment film and the sealing material and oriented along the light distribution direction of the second alignment film; having The virtual image display device according to claim 4 .

6. The first polarizing layer is a first wire grid polarizer provided on the curved surface of the second lens on the first side; a first substrate film covering the first wire-grid polarizer from the first side; having 3. The virtual image display device according to claim 1 or 2.

7. The second polarizing layer is a second wire grid polarizer provided on the curved surface of the first lens on the first side; a second substrate film covering the second wire-grid polarizer from the first side; having 3. The virtual image display device according to claim 1 or 2.

8. the second polarizing layer, the first wavelength layer, and the reflective layer are sequentially arranged between the first lens and the second lens toward the first side in the first direction, the second wavelength layer is disposed between the second lens and the first polarizing layer in the first direction.

3. The virtual image display device according to claim 1 or 2.

9. the second polarizing layer is disposed between the display element and the first lens in the first direction; In the first direction, the first-wavelength layer and the reflective layer are sequentially arranged between the first lens and the second lens toward the first side.

3. The virtual image display device according to claim 1 or 2.

10. the first polarizing layer is formed on the curved surface of the second lens on the first side and is in contact with the curved surface of the second lens on the first side; 3. The virtual image display device according to claim 1 or 2.

11. the second-wavelength layer is formed on the curved surface of the second lens on the second side that is along the curved surface of the first lens on the first side and is in contact with the curved surface of the second lens on the second side; 3. The virtual image display device according to claim 1 or 2.

12. the first-wavelength layer is formed on the curved surface of the first lens on the first side and is in contact with the curved surface of the first lens on the first side; 3. The virtual image display device according to claim 1 or 2.

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