Virtual image display device

Abstract

The invention provides a virtual image display device which is small in size, easy to manufacture and capable of exhibiting excellent optical characteristics at a wide field angle. A virtual image display device according to an embodiment includes: a display element that emits image light toward a first side in a first direction; a first lens comprising a curved surface protruding toward the display element; a second lens comprising a curved surface protruding toward the display element; a first polarization layer that is formed along the curved surface on the first side of the second lens, transmits the first polarized light, and reflects second polarized light, which is different from the first polarized light, to the second side; a second polarizing layer that transmits the first polarized light; a first wavelength layer which is formed along the curved surface of the first side of the first lens, imparts a phase difference to incident light, and transmits the incident light; a reflective layer that transmits a portion of the incident light and reflects a remaining portion of the incident light; and a second wavelength layer which is formed along the curved surface of the first side of the first lens, imparts a phase difference to the incident light, and transmits the incident light.

Description

Technical Field

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

[0002] Conventionally, virtual image display devices are known that enable the observation of a virtual image by guiding image light emitted from a display element to the viewer's eyes using optical elements such as lenses. For example, Patent Document 1 discloses a virtual image display device comprising: an image element that displays an image; a first optical section disposed in the optical path of the image light; a second optical section disposed closer to the image element than the first optical section; a half mirror disposed on a serrated surface formed at the junction of the first and second optical sections; and a transmissive / reflective selective component disposed on the emission side of the first optical section. The transmissive / reflective selective component selectively transmits or reflects light depending on the polarization state of the incident light.

[0003] Patent Document 2 discloses a thermoformed multilayer reflective polarizer for guiding image light from a display element. The thermoformed multilayer reflective polarizer is formed substantially rotationally symmetrically with respect to the optical axis of the image light passing through its vertex, and is convex relative to a plane perpendicular to the optical axis. In the thermoformed multilayer reflective polarizer, if the radius centered on the optical axis is r1 and the displacement in a plane perpendicular to the optical axis is s1, then s1 / r1 is 0.2.

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2020-024246

[0005] Patent Document 2: Japanese Patent Application No. 2018-500584

[0006] In the virtual image display device disclosed in Patent Document 1, the design and manufacture of the serrated surfaces in the optical element are somewhat complex. In the thermoformed multilayer reflective polarizer disclosed in Patent Document 2, optical properties such as imaging characteristics cannot be achieved at wide viewing angles, making it difficult to construct a telecentric optical system on the display element side and shortening the distance from the display element to the optical element positioned closest to the viewer. Therefore, there is a demand for a virtual image display device that is compact, easy to manufacture, and exhibits excellent optical properties at wide viewing angles. Summary of the Invention

[0007] The virtual image display device of this embodiment comprises: a display element that emits image light toward a first side along a first direction; a first lens that is arranged at a position closer to the first side than the display element and is composed of a curved surface that protrudes toward the display element; a second lens that is arranged at a position closer to the first side than the first lens and is composed of a curved surface that protrudes toward the display element, the curvature radius of the curved surface on the first side of the second lens being larger than the curvature radius of the curved surface on the second side opposite to the first side in the first direction; a first polarizing layer that is arranged at a position closer to the first side than the second lens and is formed along the curved surface on the first side of the second lens, so as to transmit a first polarized light in the incident light and reflect a second polarized light in the incident light that is different from the first polarized light; and a second polarizing layer that a first wavelength layer disposed between the display element and the second lens in the first direction, transmitting first polarized light in 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 on the first side of the first lens, imparting a phase difference corresponding to 1 / 4 of the wavelength of the light to the incident light and transmitting the incident 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 remaining portion 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 on the first side of the first lens, imparting a phase difference corresponding to 1 / 4 of the wavelength of the light to the incident light and transmitting the incident light. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is a schematic diagram showing the structure of the virtual image display device according to the first embodiment.

[0009] Figure 2 This is a partially exploded view showing the structure of the virtual image display device according to the first embodiment.

[0010] Figure 3 Is used to illustrate Figure 1 An exploded side view of the travel path of image light in a virtual image display device.

[0011] Figure 4 This is a schematic diagram showing the structure of a virtual image display device according to a second embodiment.

[0012] Figure 5 This is a schematic diagram showing the structure of a virtual image display device according to a third embodiment.

[0013] Description of labels

[0014] 11: Virtual image display device; 50, 60: Display element; 101: Lens (1st lens); 102: Lens (2nd lens); 111: Polarization layer (2nd polarization layer); 121: 1 / 4 wavelength layer (1st wavelength layer); 131: Reflection layer; 141: 1 / 4 wavelength layer (2nd wavelength layer); 151: Polarization layer (1st polarization layer). DETAILED DESCRIPTION

[0015] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In each of the drawings, the scale of each component may be changed to facilitate viewing of the components.

[0016] First embodiment

[0017] First, refer to Figures 1 to 3 A first embodiment of the present invention will be described. Figure 1 1 is a schematic diagram of the virtual image display device 11 according to the first embodiment. Figure 1 As shown, the virtual image display device 11 includes a display element 50 , a lens 101 , a polarizing layer 111 , a quarter wavelength layer 121 , a reflective layer 131 , a lens 102 , a quarter wavelength layer 141 , and a polarizing layer 151 .

[0018] In the virtual image display device 11, the display element 50, lens 101, polarization layer 111, 1 / 4 wavelength layer 121, reflection layer 131, 1 / 4 wavelength layer 141, lens 102, polarization layer 151 and observer's eye EY are arranged in sequence from the -Z side to the +Z side along the Z direction.

[0019] The display element 50 displays an image or video that is visually recognized by the observer and emits image light. The display element 50 is not limited to a specific type of element, and may be, for example, an imaging element composed of a self-luminous OLED (Organic Light Emitting Diode) such as an organic electro-luminescence (OLED), or a self-luminous display element such as an inorganic EL, an LED array, a laser array, or a quantum dot light-emitting element.

[0020] The display element 50 has a display surface 50p that emits the image light L1. A plurality of pixels (not shown) are arranged along the X and Y directions 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.

[0021] In the following description and drawings, two directions that are included in a plane parallel to the display surface 50p of the display element 50 and are orthogonal to each other are referred to as the X direction and the Y direction. A direction orthogonal to the X and Y directions 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 of the display element 50, lens 101, polarizing layer 111, quarter-wave layer 121, reflective layer 131, quarter-wave layer 141, lens 102, polarizing layer 151, and observer's eye EY in the X and Y directions overlap with each other.

[0022] Image light L1 is emitted toward the +Z side from each pixel of the display surface 50p of the display element 50. The image light L1 is emitted so as to expand within an XY plane including the X and Y directions as it moves toward the +Z side, with reference to an axis passing through the approximate center of each pixel and parallel to the Z direction. The observer's eye EY is located closer to the +Z side than the display element 50.

[0023] The lens 101 corresponds to the first lens and is arranged on the +Z side of the display element 50 and on the −Z side of the observer's eye EY, and on the optical path of the image light L1 emitted from the display element 50 in the Z direction.

[0024] 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 aspheric surface that protrudes toward the -Z side. A non-reflective coating (not shown) or an anti-reflective film (not shown) is applied to the first surface 101a of the lens 101. The second surface 101b is a curved surface that protrudes toward the display element 50 in the Z direction, for example, an aspheric surface that protrudes toward the -Z side. The lens 101 focuses light incident from the -Z side toward the eye EY, which is located at the center of the XY plane and on the +Z side.

[0025] The shape, radius of curvature and aspheric coefficient of the first surface 101a and the shape, radius of curvature and aspheric coefficient of the second surface 101b are appropriately set based on the size of the display surface 50p of the display element 50 in the X direction and the Y direction, the distance between the display element 50 and the observer's eye EY in the Z direction, and the refractive index of each component of the virtual image display device 11, based on the results of a ray tracing simulation based on the path of light in the virtual image display device 11, which will be described later.

[0026] The lens 101 is formed of a material that is translucent to image light in the visible wavelength range, such as a resin such as plastic. Examples of the resin material for the lens 101 include low-birefringence materials such as OKP-1 (manufacturer: Osaka Gas Chemical Co., Ltd.), an optical polyester resin.

[0027] Polarizing layer 111 is disposed on second surface 101b of lens 101, contacting the second surface 101b from the +Z side. Polarizing layer 111 has a first surface 111a on the -Z side and a second surface 111b on the +Z side. Polarizing layer 111 transmits only a predetermined linearly polarized portion of incident light. For example, the predetermined polarized light is linearly polarized light with a vibration direction parallel to the Y direction.

[0028] The polarizing layer 111 is not limited to a specific type of element as long as it transmits only predetermined linearly polarized light as described above, but is preferably formed of a wire grid polarizer 211 . Figure 2 This is a side view of some components of the virtual image display device 11 , and is a diagram obtained by enlarging the components in the Z direction as viewed from a direction perpendicular to the Z direction.

[0029] like Figure 2 As shown, the polarizing layer 111 includes a wire-grid polarizer 211 and a base film 212. The wire-grid polarizer 211 is disposed on the second surface 101b on the +Z side of the lens 101, in contact with the second surface 101b. It 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 less than 1 μm, specifically, approximately several hundred nanometers.

[0030] The base film 212 contacts the second surface 211b, which is the curved surface on the +Z side of the wire-grid polarizer 211, and covers the second surface 211b from the +Z side. The second surface 212b on the +Z side of the base film 212 is located closer to the +Z side of the second surface 101b of the lens 101, spaced apart by a substantially constant thickness. The base film 212 is translucent to light in the visible wavelength range and is made of, for example, a flexible resin. The thickness of the base film 212 in the Z direction is preferably approximately 50 to 200 μm.

[0031] Since the polarization layer 111 is composed of a wire grid polarizer 211, it is easy to form a polarization layer 111 that exhibits desired polarization characteristics on the second surface 101b, which is the curved surface of the lens 101. The deviation of the polarization characteristics exhibited by the polarization layer 111 in the XY plane is suppressed to a minimum, and the uniformity of the polarization characteristics exhibited by the polarization layer 111 in the XY plane is improved.

[0032] On the other hand, for example, in the case where the polarization layer 111 is composed of a film-shaped polarization element, when it is pasted on the second surface 101b of the lens 101, the deviation of the polarization characteristics exerted by the polarization layer 111 on the XY plane may become significant due to the different stretching degree and stress of the film-shaped polarization element depending on the position on the XY plane and the curvature radius of the second surface 101b.

[0033] When the polarizing layer 111 is formed of the wire-grid polarizer 211 as described above, the polarizing layer 111 transmits linearly polarized light having a vibration direction parallel to a direction perpendicular to the extension direction of the plurality of wires constituting the wire-grid polarizer 211. Specifically, when the polarizing layer 111 is formed of the wire-grid polarizer 211 and transmits only linearly polarized light having a vibration direction parallel to the Y direction among incident light, the plurality of wires included in the polarizing layer 111 extend parallel to the X direction.

[0034] Quarter-wavelength layer 121 contacts second surface 111b of polarization layer 111 from the +Z side and is disposed on second surface 111b. Quarter-wavelength layer 121 has first surface 121a on the -Z side and second surface 121b on the +Z side. Quarter-wavelength layer 121 imparts a phase difference of a quarter wavelength to incident light, for example, converting incident linearly polarized light into circularly polarized light, and vice versa.

[0035] The quarter-wave layer 121 can be any wavelength layer or retardation layer that transmits only the specified linearly polarized light, as described above. It is not limited to a specific type of element, but is preferably composed of a birefringent material such as liquid crystal. For example, the quarter-wave layer 121 includes an alignment film 221, a sealant 222, and liquid crystal 224, which serves as the birefringent material.

[0036] The sealant 222 is disposed on the -Z side of the reflective layer 131 and is provided on the first surface 221a of the reflective layer 131. It is positioned in the Z direction between the alignment film 221 and the reflective layer 131, with a predetermined distance from the first surface 131a of the reflective layer 131 toward the -Z side. The sealant 222 is, for example, an annular member formed of a resin or the like that is translucent to image light incident on the quarter-wave layer 121 and is disposed on the outer periphery of the reflective layer 131, centered about an axis JX parallel to the Z direction. Alternatively, the sealant 222 may be, for example, a plurality of bead-like particles formed of a resin, dispersed on the first surface 221a of the alignment film 221.

[0037] The liquid crystal 224 fills the area surrounded by the alignment film 221, the sealant 222, and the reflective layer 131, and is aligned 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, equivalent to the thickness of the sealant 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.

[0038] 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 of the seal 222, covering the liquid crystal 224 from the -Z side. The alignment film 221 is translucent to the image light incident on the quarter-wave layer 121. The alignment film 221 has a light distribution direction corresponding to the phase difference imparted to the light incident on the quarter-wave layer 121. For example, the alignment film 221 may also include a groove structure along the light distribution direction.

[0039] The quarter-wave layer 121 is made of a birefringent material, and thus, the quarter-wave layer 121 exhibiting the desired phase difference imparting characteristics can be easily formed on the second surface 111b of the polarization layer 111 along the second surface 101b of the lens 101. The deviation of the phase difference imparting characteristics exhibited by the quarter-wave layer 121 on the XY plane is suppressed to a minimum, and the uniformity of the phase difference imparting characteristics exhibited by the quarter-wave layer 121 on the XY plane is improved.

[0040] On the other hand, for example, in the case where the 1 / 4 wavelength layer 121 is composed of a film-like wavelength element or a phase difference element, when it is pasted on the second surface 111b of the polarization layer 111, the degree of stretching of the film-like polarization element varies depending on the position on the XY plane and the curvature radius of the second surface 111b, and the deviation of the polarization characteristics exerted by the polarization layer 111 on the XY plane may become significant.

[0041] 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 on the first surface 241a on the -Z side of the orientation film 241 of the quarter-wave layer 141 by vapor deposition or the like. 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, and is 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, and can be, for example, a metal vapor-deposited film, a metal thin film, or a dielectric multilayer film. The thickness of the reflective layer 131 is, for example, 15 μm or less.

[0042] The quarter-wave layer 141 contacts the second surface 131b of the reflective layer 131 from the +Z side and is provided on the second surface 131b. The quarter-wave layer 141 has a first surface 141a on the -Z side and a second surface 141b on the +Z side. The quarter-wave layer 141 imparts a quarter-wavelength phase difference to incident light, for example, converting incident linearly polarized light into circularly polarized light, and vice versa.

[0043] The quarter-wave layer 141 is not limited to a specific type of element, as long as it is a wavelength layer or retardation layer that transmits only a predetermined linearly polarized light, as described above. However, it is preferably composed of a birefringent material such as liquid crystal. For example, the quarter-wave layer 141 includes an alignment film 241, a sealant 242, and liquid crystal 244 as a birefringent material.

[0044] The seal 242 is disposed on the -Z side of the lens 102 and is provided on the first surface 102a of the lens 102. The seal 242 is, for example, an annular member formed of a resin or the like that is translucent to the image light incident on the quarter-wavelength layer 141 and is disposed on the outer periphery of the lens 102, centered about the axis JX. Alternatively, the seal 242 may be, for example, a plurality of bead-like particles formed of a resin, dispersed on the first surface 241a of the alignment film 241. The seal 242 is disposed on the +Z side of the alignment film 241 and is positioned between the alignment film 241 and the lens 102 in the Z direction, spaced a predetermined distance from the first surface 102a of the lens 102 toward the -Z side.

[0045] The liquid crystal 244 fills the area surrounded by the alignment film 241, the sealant 242, and the lens 102, and is aligned 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, that is equivalent to the thickness of the sealant 242.

[0046] The alignment film 241 is provided on the -Z side of the seal 242 along the first surface 102a of the lens 102 and in contact with the -Z side surface of the liquid crystal 244. The alignment film 241 is translucent to the image light incident on the quarter-wave layer 141. The alignment film 241 has a light distribution direction corresponding to the phase difference imparted to the light incident on the quarter-wave layer 141. For example, the alignment film 241 may also have a groove structure along the light distribution direction.

[0047] Since the quarter-wave layer 141 is made of a birefringent material, it is easy to form the quarter-wave layer 141 that exhibits the desired phase difference-imparting characteristics on the second surface 131b of the reflective layer 131 or the second surface 102b of the lens 102. The deviation of the phase difference-imparting characteristics exhibited by the quarter-wave layer 141 on the XY plane is suppressed to a minimum, and the uniformity of the phase difference-imparting characteristics exhibited by the quarter-wave layer 141 on the XY plane is improved.

[0048] When the quarter-wave layer 141 is made of a birefringent material, as an example, similar to the quarter-wave layer 121, the birefringent material is applied to the second surface 131b of the reflective layer 131 using a spray nozzle (not shown). Specifically, the birefringent material is mixed with a solvent to prepare 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 point, the birefringent material is evenly laminated on the second surface 131b of the reflective layer 131 with a substantially constant thickness. The birefringent material is then irradiated with electromagnetic waves, such as ultraviolet rays, to align its orientation with a predetermined direction, thereby performing orientation control. The predetermined direction is, for example, a direction that is 45 degrees relative to each of the X and Y directions and is perpendicular to the Z direction.

[0049] When controlling the orientation and controlling and fixing the orientation of the birefringent material, as a method other than the method of irradiating ultraviolet rays as described above, for example, the solvent can be slowly removed according to the arrangement speed of the liquid crystal molecules, or a cholesteric liquid crystal composition can be used as the birefringent material and the composition can be photocured between liquid crystal phase states.

[0050] The quarter-wave layer comprising the quarter-wave layer 141 can also be formed and fabricated as described below. For example, a photo-crosslinkable polymer liquid crystal material is coated onto a substrate made of a flexible transparent resin configured to suppress deviations in transmission and polarization properties due to elongation and bending, thereby forming a photo-crosslinkable polymer liquid crystal material layer, i.e., a thin film composed of the photo-crosslinkable polymer liquid crystal material. By irradiating the thin film with linearly polarized ultraviolet light with a controlled polarization direction, the thin film can be cured, thereby controlling the orientation of the molecular species exhibiting liquid crystal properties. In this case, the molecular species exhibiting liquid crystal properties that extend in a direction consistent with the polarization direction of the ultraviolet light are crosslinked, and their orientation is fixed in the same direction as the polarization direction. Subsequently, by annealing the film, the molecular species exhibiting liquid crystal properties that do not change in orientation under ultraviolet light can be liquid-crystallized, aligning the orientation of these molecular species with the polymer portion that has already achieved the target orientation. As a result, the orientation is fixed. That is, a wavelength layer is obtained which is composed of a thin film in which most of the molecular species exhibiting liquid crystallinity constituting the photo-crosslinkable polymer liquid crystal material are aligned in their orientation directions. In such a wavelength layer, retardation can be adjusted by adjusting the thickness.

[0051] The lens 102 corresponds to the second lens and is arranged on the +Z side of the lens 101 and on the −Z side of the observer's eye EY, and is arranged on the optical path of the image light L1 emitted from the reflective layer 131 to the +Z side.

[0052] 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, aspheric surfaces that protrude toward the -Z side. For example, the lens 102 is a positive meniscus lens with a convex surface on the -Z side. The lens 102 focuses light incident from the -Z side toward the eye EY, which is located at the center of the XY plane and on the +Z side.

[0053] The refractive index of lens 102 is approximately 0.1 to 0.2 lower than that of lens 101. This makes it easy to construct a telecentric optical system including lenses 101 and 102. Lens 102 is formed from a material that is translucent to image light in the visible wavelength range, such as a resin such as plastic. Examples of the resin material for lens 102 include APEL (registered trademark, manufacturer: 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 lens 102, or an anti-reflective film (not shown) is provided.

[0054] 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 greater 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 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 observer's eye EY in the Z direction, and the refractive index of each component of the virtual image display device 11, as well as the results of a ray tracing simulation of the path of light in the virtual image display device 11, which will be described later.

[0055] Alternatively, the quarter-wavelength layer 141 may be in contact with the reflective layer 131 from the +Z side.

[0056] Polarizing layer 151 contacts second surface 102b of lens 102 from the +Z side and is disposed on second surface 102b. Polarizing layer 151 has a first surface 151a on the -Z side and a second surface 151b on the +Z side. Polarizing layer 151 transmits only a predetermined linearly polarized portion of incident light and reflects all other light. For example, the predetermined polarized light is linearly polarized light with a vibration direction parallel to the Y direction.

[0057] The polarizing layer 151 is not limited to a specific type of element, as long as it transmits only predetermined linearly polarized light and reflects light other than the predetermined linearly polarized light, as described above. However, it is preferably formed of a wire grid polarizer. Forming the polarizing layer 151 of a wire grid polarizer facilitates forming a polarizing layer 151 exhibiting desired polarization characteristics on the second surface 102b, which is the curved surface of the lens 102. Variation in the polarization characteristics exhibited by the polarizing layer 151 on the XY plane is minimized, and the uniformity of the polarization characteristics exhibited by the polarizing layer 151 on the XY plane is improved.

[0058] The polarizing layer 151 includes a wire-grid polarizer 251 and a base film 252. The wire-grid polarizer 251 is disposed on the second surface 102b on the +Z side of the lens 102, in contact with the second surface 102b. It has a substantially constant thickness along the second surface 102b. The thickness of the wire-grid polarizer 251, that is, the thickness of the multiple wires of the wire-grid polarizer 251, is less than 1 μm, specifically, approximately several hundred nanometers.

[0059] The base film 252 contacts the second surface 251b, which is the curved surface on the +Z side of the wire-grid polarizer 251, and covers the second surface 251b from the +Z side. The second surface 252b on the +Z side of the base film 252 is located closer to the +Z side than the second surface 102b of the lens 102, spaced apart by a substantially constant thickness. The base film 252 is translucent to light in the visible wavelength range and is made of, for example, a flexible resin. The thickness of the base film 252 in the Z direction is preferably approximately 50 to 200 μm.

[0060] When the polarizing layer 151 is formed of the wire grid polarizer 251 as described above, the polarizing layer 151 transmits linearly polarized light having a vibration direction parallel to a direction perpendicular to the extending direction of the plurality of wires constituting the wire grid polarizer 251. Specifically, when the polarizing layer 151 is formed of the wire grid polarizer 251 and transmits only linearly polarized light having a vibration direction parallel to the Y direction among incident light, the plurality of wires included in the polarizing layer 151 extend parallel to the X direction.

[0061] Figure 3 1 is a diagram for explaining the path of image light in the virtual image display device 11 according to the first embodiment. Figure 3 In order to easily understand the polarization of image light, the components are separated from each other in the Z direction.

[0062] like Figure 3As shown, image light L1 emitted from display surface 50p of display element 50 travels toward the +Z side, is refracted by first surface 101a of lens 101, and approaches axis JX, which passes through the center of display element 50 in the X and Y directions, on the XY plane. Image light L1 incident on lens 101 from first surface 101a is refracted again by second surface 101b, is emitted from lens 101, and is incident on polarizing layer 111. Of the image light L1 incident on polarizing layer 111, linearly polarized light with a polarization direction parallel to the Y direction, i.e., image light L2, is transmitted through polarizing layer 111 and emitted toward the +Z side. Of the image light L1 incident on polarizing layer 111, linearly polarized light with a polarization direction not parallel to the Y direction, i.e., light other than image light L2, is reflected by polarizing layer 111 and emitted toward the -Z side or absorbed by polarizing layer 111.

[0063] Image light L2 emitted from polarizing layer 111 toward the +Z side enters quarter-wave layer 121, where it is converted into circularly polarized image light L3. Image light L3 is right-handed or left-handed circularly polarized light, for example, right-handed circularly polarized light. Image light L3 is emitted from quarter-wave layer 121 toward the +Z side and enters reflective layer 131. Approximately half of the image light L3 incident on reflective layer 131 is transmitted through reflective layer 131 and emitted toward the +Z side. The remaining approximately half of the image light L3 incident on reflective layer 131 is reflected by reflective layer 131 and emitted toward the -Z side.

[0064] Image light L31 emitted toward the +Z side from reflective layer 131 enters quarter-wave layer 141 and is converted by quarter-wave layer 141 into linearly polarized image light L4. The polarization direction of image light L4 is parallel to the X direction and perpendicular to the Y direction. Image light L4 exits quarter-wave layer 141 toward the +Z side and enters lens 102.

[0065] Image light L4 incident on lens 102 is refracted by first surface 102a of lens 102, approaches axis JX in the XY plane, and reaches second surface 102b of lens 102. Image light L4 that reaches second surface 102b of lens 102 reaches first surface 151a 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 toward the -Z side, emitting as image light L5 in a direction away from axis JX in the XY plane.

[0066] Image light L5 emitted from lens 102 toward the -Z side enters quarter-wave layer 141, where it is converted into right-handed circularly polarized light, namely image light L6, which then exits from quarter-wave layer 141 toward the -Z side. Image light L6 emitted from quarter-wave layer 141 toward the -Z side enters reflective layer 131. Approximately half of the image light L6 incident on reflective layer 131, image light L61, is transmitted through reflective layer 131 and exits toward the -Z side. Like image light L6 incident on reflective layer 131 from the +Z side, image light L61 is right-handed circularly polarized light. The remaining approximately half of the image light L6 incident on reflective layer 131, image light L62, is reflected by reflective layer 131 and exits toward the +Z side. The image light L62 is reflected by the reflective layer 131 and is thereby converted into left-hand circularly polarized light opposite to the image light L6 incident on the reflective layer 131 from the +Z side.

[0067] Image light L62 emitted from the reflective layer 131 toward the +Z side enters the quarter-wave layer 141, where it is converted into linearly polarized image light L7, which is then emitted from the quarter-wave layer 141 toward the +Z side. The polarization direction of image light L7 is parallel to the Y direction. Image light L7 emitted from the quarter-wave layer 141 toward the +Z side passes through the lens 102 and is emitted toward the +Z side. Passing through the lens 102, the image light L7 approaches the axis JX on the XY plane. Image light L7 emitted from the lens 102 toward the +Z side passes through the polarizing layer 151 and is emitted toward the +Z side, reaching a predetermined imaging position located on the +Z side relative to the polarizing layer 151 and relative to the observer's eye EY.

[0068] Image light L61 emitted from reflective layer 131 toward the -Z side enters quarter-wave layer 121 and is converted by quarter-wave layer 121 into linearly polarized image light L8. The polarization direction of image light L8 is parallel to the Y direction. Image light L8 passes through polarizing layer 111 in the Z direction and returns to display element 50 from the -Z side.

[0069] Image light L1 emitted from multiple pixels on the display surface 50p of the display element 50 propagates as described above, and image light L7 is imaged at a predetermined imaging position, forming a virtual image. The observer observes the virtual image from the +Z side. In the virtual image display device 11, image light L5 emitted from at least the outer periphery of the XY plane of the polarizing layer 151 toward the -Z side is reflected further toward the outer periphery than image light L4 incident on the outer periphery of the polarizing layer 151 from the -Z side. Therefore, the observer can observe the virtual image at a wide viewing angle. In the virtual image display device 11, excellent imaging characteristics can be obtained even at a wide viewing angle.

[0070] 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-wavelength layer (first wavelength layer) 121, a reflective layer 131, and a quarter-wavelength 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 positioned closer to the +Z side than the display element 50 and comprises a first surface (curved surface) 101a and a second surface (curved surface) 101b that protrude toward the display element 50. The lens 102 is positioned closer to the +Z side than the lens 101 and comprises 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 the second surface 102b on the +Z side of the lens 102 (the curved surface on the first side) is larger than the radius of curvature of the first surface 102a on the -Z side, which is the side opposite to the +Z side in the Z direction. The polarizing layer 151 is arranged closer to the +Z side than the lens 102 and is closer to the observer's eye EY than other components of the virtual image display device 11. The polarizing layer 151 is formed along the second surface 102b on the +Z side of the lens 102. The polarizing layer 151 transmits linearly polarized light (first polarized light) with a polarization direction parallel to the Y direction in the incident light including the image light (light) L4, and reflects polarized light (second polarized light) other than the linearly polarized light with a polarization direction parallel to the Y direction in the incident light toward the -Z side in the Z direction (the second side, which is the side opposite to the first side). The polarizing layer 111 is positioned between the display element 50 and the lens 102 in the Z direction, formed along the second surface 101b of the lens 101 and the first surface 102a of the lens 102. It transmits linearly polarized light parallel to the Y direction in the incident light. The quarter-wavelength layer 121 is positioned between the polarizing layer 111 and the lens 102 in the Z direction, formed along the second surface 101b (the first curved surface) of the lens 101 and the first surface 102a of the lens 102. It imparts a phase difference corresponding to one-quarter of the wavelength of the incident light to the incident light, thereby transmitting the incident light. The reflective layer 131 is positioned between the quarter-wavelength layer 121 and the lens 102 in the Z direction, formed along the second surface 101b (the first curved surface) of the lens 101 and the first surface 102a of the lens 102. It transmits a portion of the incident light and reflects the remaining portion. The quarter wavelength layer 141 is arranged 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 102a of the lens 102. It imparts a phase difference corresponding to 1 / 4 of the wavelength of the light to the incident light and allows the incident light to pass through.

[0071] In the virtual image display device 11 of the first embodiment, lenses 101 and 102 are formed of curved surfaces that protrude in the same direction toward the display element 50 in the Z direction. The polarizing layer 111, quarter-wave layer 121, reflective layer 131, quarter-wave layer 141, and polarizing layer 151 are formed along the second surface 101b of lens 101 or the second surface 102b of lens 102, enabling design based on ray tracing methods of geometric optics. Therefore, the virtual image display device 11 of the first embodiment is compact and easy to manufacture. Furthermore, in the virtual image display device 11 of the first embodiment, the radius of curvature of the second surface 102b of 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 inverse of the radius of curvature. Therefore, the image light is folded back and propagated in the Z direction. The image light including the image light L5 is folded radially outward relative to the axis JX by the polarizing layer 151, and a virtual image is formed at a predetermined imaging position. Therefore, the virtual image display device 11 of the first embodiment exhibits excellent optical characteristics over a wide viewing angle.

[0072] In the virtual image display device 11 of the first embodiment, quarter-wavelength layers 121 and 141, located between the lenses 101 and 102 in the Z direction in which image light beams L1 to L7 propagate, are formed along the second surface 101b of lens 101 and the first surface 102a of lens 102. Specifically, in the virtual image display device 11 of the first embodiment, quarter-wavelength layers 121 and 141 do not utilize retardation films disposed on a flat wave plate or a flat substrate, as is conventionally done. Instead, the material of the quarter-wavelength layers 121 and 141 is formed along the second surface 101b and the first surface 102a, eliminating phase disturbances between the second surface 101b and the first surface 102a. Consequently, the virtual image display device 11 of the first embodiment exhibits excellent optical characteristics over a wide viewing angle, ensuring sufficient light intensity for image light directed toward the viewer's eye EY and improving virtual image visibility. In the virtual image display device 11 of the first embodiment, a viewing angle exceeding 100 degrees can be achieved by using a relatively small display element 50 of, for example, 1.5 inches or less.

[0073] In the virtual image display device 11 according to the first embodiment, the refractive index of the lens 102 is lower than the refractive index of the lens 101 .

[0074] 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 with respect to the axis JX. This allows for a thinner overall device and an expanded viewing angle.

[0075] In the virtual image display device 11 of the first embodiment, a polarizing layer 111, a quarter-wavelength layer 121, a reflecting layer 131, and a quarter-wavelength layer 141 are arranged in this order from the -Z side toward the +Z side between the lens 101 and the lens 102 in the Z direction. The polarizing layer 111, the quarter-wavelength layer 121, the reflecting layer 131, and the quarter-wavelength layer 141 are stacked between the lenses 101 and 102.

[0076] According to the virtual image display device 11 of the first embodiment, a thin folding optical system with a suppressed size in the Z direction is configured as described above, and excellent optical characteristics and telecentricity are achieved at a wide viewing angle, thereby obtaining a highly visible virtual image.

[0077] In the virtual image display device 11 of the first embodiment, the quarter-wavelength layer 121 includes an alignment film (first alignment film) 221, a sealant 222, and liquid crystal 224, a birefringent material. The alignment film 221 is provided along the 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, sandwiched therebetween with a predetermined distance from the second surface 221b on the +Z side of the alignment film 221. The liquid crystal 224 fills the area surrounded by the alignment film 221, the sealant 222, and the reflective layer 131, and is aligned along the light distribution direction of the alignment film 221.

[0078] According to the virtual image display device 11 of the first embodiment, the quarter-wavelength layer 121 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. This layer uniformly imparts a phase difference corresponding to one-quarter of the wavelength to the image light L3 without causing phase disturbance. As a result, the virtual image display device 11 of the first embodiment can achieve excellent optical characteristics over a wide viewing angle.

[0079] In the virtual image display device 11 of the first embodiment, the quarter-wavelength layer 141 is constructed similarly to the quarter-wavelength layer 121, including an alignment film (second alignment film) 241, a sealant 242, and liquid crystal 244, a birefringent material. The alignment film 241 is provided along the 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, spaced a certain distance from the second surface 241b on the +Z side of the alignment film 241 toward the +Z side. The liquid crystal 244 fills the area surrounded by the alignment film 241, the sealant 242, and the lens 102, and is aligned along the light distribution direction of the alignment film 241.

[0080] According to the virtual image display device 11 of the first embodiment, a quarter-wavelength layer 141 can be provided along the second surface 101b of the lens 101, specifically along the first surface 102a of the lens 102. This layer uniformly imparts a phase difference corresponding to one-quarter of the wavelength to the image light L31, L5, L62, etc., without causing phase disturbance. As a result, the virtual image display device 11 of the first embodiment can achieve excellent optical characteristics over a wide viewing angle.

[0081] In the virtual image display device 11 of the first embodiment, the polarizing layer 111 includes a wire grid polarizer (second wire grid polarizer) 211 provided on the second surface 101 b of the lens 101 and a base film (second base film) 212 covering the wire grid polarizer 211 from the +Z side.

[0082] According to the virtual image display device 11 of the first embodiment, a polarizing layer 111 can be provided along the second surface 101b of the lens 101. The polarizing layer 111 emits only predetermined linearly polarized light from among the image lights L31, L5, L62, etc., without causing deviation in polarization characteristics. As a result, the virtual image display device 11 of the first embodiment can achieve excellent optical characteristics over a wide viewing angle.

[0083] In the virtual image display device 11 of the first embodiment, the polarizing layer 151 includes a wire grid polarizer (first wire grid polarizer) 251 provided on the second surface 102 b of the lens 102 and a base film (first base film) 252 covering the wire grid polarizer 251 from the +Z side.

[0084] According to the virtual image display device 11 of the first embodiment, a polarizing layer 151 can be provided along the second surface 102b of the lens 102. The polarizing layer 151 emits only predetermined linearly polarized light from among the image lights L4, L7, etc., without causing deviation in polarization characteristics. As a result, the virtual image display device 11 of the first embodiment can achieve excellent optical characteristics over a wide viewing angle.

[0085] In the virtual image display device 11 of the first embodiment, the polarizing layer 151 is formed on the second surface 102 b of the lens 102 and is in contact with the second surface 102 b.

[0086] The virtual image display device 11 of the first embodiment can achieve miniaturization, i.e., thinning, in the Z direction. Furthermore, the virtual image display device 11 of the first embodiment can prevent the polarization state of the image light, including the image lights L4 and L7, emitted from the lens 102 and incident on the polarization layer 151 from being disturbed before entering the polarization layer 151, thereby ensuring that the polarization state of the image light functions as intended and achieving excellent optical characteristics.

[0087] In the virtual image display device 11 of the first embodiment, the quarter-wavelength layer 141 is formed along the second surface 101b of the lens 101 on the first surface 102a of the lens 102 having the same curvature radius as the second surface 101b and in contact with the first surface 102a.

[0088] The virtual image display device 11 of the first embodiment can achieve miniaturization, i.e., thinning, in the Z direction. Furthermore, the virtual image display device 11 of the first embodiment can prevent the phase of the image light, including the image lights L31, L5, and L62, from significantly changing before entering the quarter-wavelength layer 141, thereby imparting a desired phase difference to the phase of the image light and achieving excellent optical characteristics.

[0089] Furthermore, in the virtual image display device 11 of the first embodiment, the display element 50, lens 101, polarizing layer 111, quarter-wavelength layer 121, reflective layer 131, quarter-wavelength layer 141, lens 102, and polarizing layer 151 are arranged sequentially from the -Z side to the +Z side, with adjacent components in the Z direction in contact with each other. This allows for miniaturization of the virtual image display device 11 of the first embodiment in the Z direction, i.e., a reduction in the overall thickness of the device. Furthermore, as described above, by allowing adjacent components, i.e., devices or layers, in the Z direction of the virtual image display device 11 of the first embodiment to contact each other, the optical effects of each layer can be more accurately imparted to image light, resulting in desired excellent optical characteristics and a clear virtual image.

[0090] Second embodiment

[0091] Next, refer to Figure 4 The second embodiment of the present invention will be described. Regarding the virtual image display devices of each of the following embodiments, only the structures that differ from the virtual image display device 11 of the first embodiment will be described. Among the components of the virtual image display devices of each embodiment, components identical to those of the virtual image display device 11 of the first embodiment are denoted by the same reference numerals as those of the corresponding components of the virtual image display device 11 of the first embodiment. Descriptions of components identical to those of the virtual image display device 11 of the first embodiment will be omitted.

[0092] Figure 4 1 is a schematic diagram of a virtual image display device 12 according to the second embodiment. Figure 4 As shown, 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 wavelength layer 121, a reflective layer 131, a lens 102, a quarter wavelength layer 141, and a polarizing layer 151. In the virtual image display device 12, the quarter wavelength layer 141 is disposed between the lens 102 and the polarizing layer 151 in the Z direction.

[0093] 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 102b of the lens 102 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 102b of the lens 102, the solvent is removed. At this point, the birefringent material is evenly layered on the second surface 102b of the lens 102 with a substantially constant thickness. Then, the birefringent material is irradiated with electromagnetic waves such as ultraviolet rays to align the orientation of the birefringent material with a predetermined direction, thereby performing orientation control. The predetermined direction is, for example, a direction that is 45 degrees relative to each of the X and Y directions and is orthogonal to the Z direction.

[0094] In the virtual image display device 12 of the second embodiment described above, the same operational effects as those achieved by the same configuration as the virtual image display device 11 of the first embodiment can be achieved.

[0095] In the virtual image display device 12 of the second embodiment, a polarizing layer 111, a quarter-wavelength layer 121, and a reflecting layer 131 are arranged in this order 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.

[0096] According to the virtual image display device 12 of the second embodiment, like the virtual image display device 11 of the first embodiment, a thinner folding optical system is constructed that suppresses the size in the Z direction, and excellent optical characteristics and telecentricity are taken into account at a wide field of view to obtain a virtual image with high visibility.

[0097] Furthermore, in the virtual image display device 12 of the second embodiment, a coating liquid containing a birefringent material is applied to the second surface 102b of the lens 102, which is concave when viewed from the +Z side, at a uniform thickness and oriented in a predetermined light distribution direction. This allows a quarter-wavelength layer 141 to be provided along the second surface 102b of the lens 102. This layer uniformly imparts a phase difference equivalent to one-quarter of the wavelength to the image light beams L31, L5, and L62, without causing phase disturbance. As a result, the virtual image display device 12 of the second embodiment can also achieve excellent optical characteristics over a wide viewing angle.

[0098] Here, an example of the design of the virtual image display device 12 of the second embodiment is described. The size of the display surface 50p of the display element 50 in the X and Y directions is set to 1.0 inches to 1.5 inches, specifically, to 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 set to 17 mm or less, specifically, to 16 mm. The distance in the Z direction from the display surface 50p of the display element 50 to the predetermined imaging position of the image light is set to 23 mm or less, specifically, to 22 mm. The maximum thickness of the lens 102 in the Z direction, that is, the thickness of the lens 102 on the axis JX, is set to 12 mm or less, specifically, to 11 mm.

[0099] The resin material for lens 101 is OKP-1, and the resin material for lens 102 is APEL, specifically APEL5514. The refractive index of OKP-1 constituting 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 constituting 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.

[0100] By applying the above-described design and conditions to the structure of the virtual image display device 12, a field of view (FOV) of 100 degrees or greater, specifically, 120 degrees, can be achieved. Furthermore, by applying the above-described design and conditions to the structure of the virtual image display device 12, a telecentric widest field of view of 10 degrees or less, specifically, 7 degrees or less, can be achieved.

[0101] Table 1 shows examples of surface data of the first surface 101 a and the second surface 101 b of the lens 101 , and the first surface 102 a and the second surface 102 b of the lens 102 .

[0102] [Table 1]

[0103]

[0104] The aspheric coefficients of each surface in Table 1 represent the coefficients A4, A6, A8, A in the following formula (1): 10 In formula (1), R represents the radius of curvature. In formula (1), K represents the cone coefficient.

[0105]

[0106] Third embodiment

[0107] Next, refer to Figure 5A third embodiment of the present invention will be described. Figure 5 : is a schematic diagram of the virtual image display device 13 of the third embodiment. Figure 5 As shown, the virtual image display device 13 includes a display element 60 , a lens 101 , a polarizing layer 111 , a quarter wavelength layer 121 , a reflecting layer 131 , a quarter wavelength layer 141 , a lens 102 , and a polarizing layer 151 .

[0108] Display element 60, like display element 50, displays images or videos viewed by an observer and emits image light. Display element 60 is, for example, a liquid crystal display (LCD), and is connected to a terminal device or image generation device (not shown) via a wired or wireless connection. It emits image light based on image information received from the terminal device or image generation device. Examples of the terminal device or image generation device are smartphones, tablet devices, or computers.

[0109] The display element 60 has a display surface 60p that emits the image light L1. A plurality of pixels (not shown) are arranged along the X and Y directions 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.

[0110] 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, immediately adjacent to the display element 60 on the +Z side thereof, and 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 orthogonal to the axis JX and parallel to the display surface 60p of the display element 60.

[0111] The polarizing layer 111 of the virtual image display device 13 may be a wire grid polarizer 211, an absorbing polarizing plate, or a polarizing element attached to a liquid crystal display or liquid crystal panel. Furthermore, an appropriate distance may be provided between the display element 60 and the polarizing layer 111 in the Z direction.

[0112] In the virtual image display device 12 of the second embodiment described above, the same operational effects as those achieved by the same configuration as the virtual image display device 11 of the first embodiment can be achieved.

[0113] 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-wavelength layer 121 and a reflective layer 131 are disposed in this order toward the +Z side between the lens 101 and the lens 102 in the Z direction.

[0114] According to the virtual image display device 13 of the third embodiment, like the virtual image display device 11 of the first embodiment, a thinner folding optical system is constructed that suppresses the size in the Z direction, and excellent optical characteristics and telecentricity are taken into account at a wide field of view to obtain a virtual image with high visibility.

[0115] In the virtual image display device 13 of the third embodiment, the quarter-wavelength layer 121 is formed on the second surface 101 b of the lens 101 and is in contact with the second surface 101 b .

[0116] The virtual image display device 13 of the third embodiment can achieve miniaturization, i.e., thinning, in the Z direction. Furthermore, the virtual image display device 13 of the third embodiment can prevent the phase of the image light including the image light L1 from significantly changing before entering the quarter-wave layer 121, thereby imparting a desired phase difference to the phase of the image light and achieving excellent optical characteristics.

[0117] Other methods

[0118] Furthermore, in the virtual image display device of the present disclosure, the polarizing layer (first polarizing layer) 151 is formed along the second surface (the side surface on the first side) 102b of the lens 102. Specifically, the polarizing layer 151 formed along the second surface 102b includes a state where the polarizing layer 151 is directly formed or coated on the second surface 102b of the lens 102, as in the aforementioned embodiments, and has a surface having a radius of curvature equivalent to that of the second surface 102b. Furthermore, the polarizing layer 151 includes a state where the polarizing layer 151 is arranged close to the second surface 102b with a small gap in the Z direction that does not change the emission characteristics of the image light, and has a surface having a radius of curvature equivalent to that of the second surface 102b. Alternatively, the polarizing layer 151 includes a state where the polarizing layer 151 has a thin layer structure that does not affect the polarization characteristics of the image light in the Z direction, and has a surface having a radius of curvature equivalent to that of the second surface 102b.

[0119] Similarly, in the virtual image display device of the present disclosure, the quarter-wave layer (first wavelength layer) 121 is formed along the second surface (first side surface) 101b of the lens 101. Specifically, the quarter-wave layer 121 formed along the second surface 101b includes a state where the quarter-wave layer 121 is directly formed or coated on the second surface 101b of the lens 101, as in the third embodiment described above, and has a surface curvature radius equivalent to that of the second surface 101b. It also includes a state where the quarter-wave layer 121 is arranged close to the second surface 101b with a small gap in the Z direction that does not change the emission characteristics of the image light, and has a surface curvature radius equivalent to that of the second surface 101b. Alternatively, as in the first and second embodiments described above, a thin layer structure such as a polarizing layer 111 that does not affect the phase difference of the image light in the Z direction is sandwiched between the quarter-wave layer 121 and the second surface 101b, and has a surface curvature radius equivalent to that of the second surface 101b.

[0120] In addition, in the virtual image display device disclosed in the present invention, the second reflective layer or reflective layers can be formed on the surface of the first side or the second side of the layer adjacent to the first direction as described in the above-mentioned embodiments, or can be arranged close to the layer adjacent to the first direction with a small gap, or can have a thin layer structure between the layers adjacent to the first direction that does not cause unexpected effects on the optical properties of the image light.

[0121] While preferred embodiments of the present invention have been described in detail above, the present invention is not limited to these specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims.

[0122] For example, the virtual image display device according to each of the above-described embodiments can be applied to a head-mounted display device such as a head-mounted display, and can be appropriately applied to optical devices other than the head-mounted display device.

[0123] Summary of the Disclosure

[0124] The following is a summary of the present disclosure.

[0125] (Supplementary note 1) A virtual image display device comprising: a display element that emits image light along a first direction toward a first side; a first lens that is arranged at a position closer to the first side than the display element and is composed of a curved surface that protrudes toward the display element; a second lens that is arranged at a position closer to the first side than the first lens and is composed of a curved surface that protrudes toward the display element, the curvature radius of the curved surface on the first side of the second lens being larger than the curvature radius of the curved surface on the second side opposite to the first side in the first direction; a first polarizing layer that is arranged at a position closer to the first side than the second lens and is formed along the curved surface on the first side of the second lens so as to transmit a first polarized light in the incident light and reflect a second polarized light in the incident light that is different from the first polarized light; a second polarizing layer that is arranged at a position closer to the first side than the second lens and is formed along the curved surface on the first side of the second lens The lens element is configured between the display element and the second lens in the first direction, so as to transmit the first polarized light in the incident light; the lens element is configured between the second polarizing layer and the second lens in the first direction, and the first polarized light in the incident light is transmitted; the lens element is configured between the second polarizing layer and the second lens in the first direction, and the first polarized light in the incident light is transmitted; the lens element is configured between the second polarizing layer and the second lens in the first direction, and the first polarized light in the incident light is transmitted; the lens element is configured between the second polarizing layer and the second lens in the first direction, and the first polarized light in the incident light is transmitted; the lens element is configured between the second polarizing layer and the second lens in the first direction, and the first polarized light in the incident light is transmitted; the lens element is configured between the second polarizing layer and the second lens in the first direction, and the second polarized light in the incident light is transmitted; the lens element is configured between the second polarizing layer and the second lens in the first direction, and the second polarized light in the incident light is transmitted; the lens element is configured between the second polarizing layer and the second lens in the first direction, and the second polarized light in the incident light is transmitted;

[0126] According to the structure of Supplementary Note 1, the virtual image display device is compact and easy to manufacture, and exhibits excellent optical characteristics with good telecentricity and a wide viewing angle.

[0127] (Supplementary Note 2) The virtual image display device according to Supplementary Note 1, wherein the refractive index of the second lens is lower than the refractive index of the first lens.

[0128] According to the structure of Supplementary Note 2, it is possible to achieve a reduction in thickness of the entire device and an increase in the viewing angle.

[0129] (Note 3) The virtual image display device according to Note 1 or 2, wherein, in the first direction, between the first lens and the second lens, the second polarization layer, the first wavelength layer, the reflection layer and the second wavelength layer are arranged in sequence toward the first side.

[0130] According to the configuration of Supplementary Note 3, a thin telecentric optical system can be easily configured along the first direction, and excellent optical characteristics can be obtained at a wide angle of view.

[0131] (Note 4) The virtual image display device according to Note 3, wherein the first wavelength layer comprises: a first orientation film, which is arranged along the curved surface of the second side of the second lens; a sealing member, which is arranged on the second side of the first orientation film and is sandwiched so as to be spaced a certain distance from the surface of the second side of the first orientation film toward the second side; and a birefringent material, which is filled in the space surrounded by the first orientation film and the sealing member and is oriented along the light distribution direction of the first orientation film.

[0132] According to the structure of Supplementary Note 4, a first wavelength layer with less phase difference disturbance than conventional film-shaped wavelength plates can be arranged along the convex curved surface protruding toward the display element, that is, the curved surface on the second side of the second lens. As a result, excellent optical characteristics can be obtained, and the visibility of the virtual image is improved.

[0133] (Note 5) A virtual image display device according to Note 4, wherein the second wavelength layer comprises: a second orientation film, which is arranged along the curved surface of the second side of the second lens; a seal, which is arranged on the second side of the second orientation film and is sandwiched so as to be spaced a certain distance from the surface of the second side of the second orientation film toward the second side; and a birefringent material, which is filled in the area surrounded by the second orientation film and the seal and is oriented along the light distribution direction of the second orientation film.

[0134] According to the configuration of Supplementary Note 5, a second wavelength layer having less phase difference disturbance than conventional film-shaped wavelength plates can be arranged along the curved surface on the second side of the second lens. As a result, excellent optical characteristics can be obtained, and the visibility of the virtual image is improved.

[0135] (Note 6) A virtual image display device according to any one of Notes 1 to 5, wherein the first polarization layer comprises: a first wire grid polarizer, which is arranged on the curved surface of the first side of the second lens; and a first base film, which covers the first wire grid polarizer from the first side.

[0136] According to the structure of Supplementary Note 6, a first modulation layer having less polarization characteristic variation than conventional film-shaped polarizing elements can be arranged along the curved surface of the first side of the second lens recessed toward the display element. As a result, excellent optical characteristics can be obtained, and the visibility of the virtual image is improved.

[0137] (Note 7) A virtual image display device according to any one of Notes 1 to 6, wherein the second polarization layer comprises: a second wire grid polarizer, which is arranged on the curved surface of the first side of the first lens; and a second base material film, which covers the second wire grid polarizer from the first side.

[0138] According to the structure of Supplementary Note 7, a second modulation layer having a smaller deviation in polarization characteristics than conventional film-shaped polarizing elements can be arranged along the curved surface of the first side of the first lens, which is recessed toward the display element. As a result, excellent optical characteristics can be obtained, and the visibility of the virtual image is improved.

[0139] (Note 8) The virtual image display device according to Note 1 or 2, wherein, in the first direction, between the first lens and the second lens, the second polarization layer, the first wavelength layer and the reflection layer are arranged in sequence toward the first side, and in the first direction, the second wavelength layer is arranged between the second lens and the first polarization layer.

[0140] According to the configuration of Supplementary Note 8, a thin telecentric optical system can be easily configured along the first direction, and excellent optical characteristics can be obtained at a wide angle of view.

[0141] (Note 9) The virtual image display device according to Note 1 or 2, wherein the second polarization layer is arranged between the display element and the first lens in the first direction, and the first wavelength layer and the reflection layer are arranged in sequence toward the first side between the first lens and the second lens in the first direction.

[0142] According to the structure of Supplementary Note 9, the second polarizing layer is arranged on the first side of the display element, and a thin telecentric optical system can be easily constructed along the first direction, thereby obtaining excellent optical characteristics at a wide viewing angle.

[0143] (Supplementary Note 10) The virtual image display device according to Supplementary Note 1 or Supplementary Note 2, wherein the first polarizing layer is formed on the curved surface on the first side of the second lens and is in contact with the curved surface on the first side of the second lens.

[0144] The structure of Supplementary Note 10 can further reduce the thickness of the virtual image display device. In addition, the polarization state of the image light emitted from the second lens is less likely to be disturbed before entering the first polarizing layer, and excellent optical characteristics can be obtained.

[0145] (Note 11) A virtual image display device according to Note 1 or Note 2, wherein the second wavelength layer is formed on the curved surface on the second side of the second lens along the curved surface on the first side of the first lens, and contacts the curved surface on the second side of the second lens.

[0146] The virtual image display device can be further thinned according to the structure of Supplementary Note 11. In addition, the phase of the image light is less likely to be disturbed before entering the second wavelength layer, and excellent optical characteristics can be obtained.

[0147] (Supplementary Note 12) The virtual image display device according to Supplementary Note 1 or Supplementary Note 2, wherein the first wavelength layer is formed on the curved surface on the first side of the first lens and is in contact with the curved surface on the first side of the first lens.

[0148] According to 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 entering the first wavelength layer, and thus excellent optical characteristics can be obtained.

Claims

1. A virtual image display device comprising: a display element that emits image light; a first lens on which the image light emitted from the display element is incident, the first lens having a first incident surface protruding toward the display element and a first exit surface from which the image light is emitted; a second lens on which the image light emitted from the first emission surface of the first lens is incident, the second lens having a second incident surface protruding toward the display element and a second emission surface having a larger curvature radius than the second incident surface and emitting the image light; a first polarizing layer provided along the second exit surface of the second lens, disposed closer to the first side than the second lens, formed along the curved surface on the first side of the second lens, transmitting first polarized light in incident light and reflecting second polarized light different from the first polarized light in the incident light; a second polarizing layer disposed between the display element and the second lens in a first direction in which the first lens and the second lens are arranged, and transmitting the first polarized light in the incident light; a first wavelength layer disposed between the second polarization layer and the second lens in the first direction, and imparting a phase difference corresponding to 1 / 4 of the wavelength of the light to incident light and transmitting the incident light; a reflective layer disposed between the first wavelength layer and the second lens in the first direction, transmitting a portion of incident light and reflecting the remaining portion of the incident light; as well as The second wavelength layer is disposed between the reflective layer and the first polarizing layer in the first direction, and provides a phase difference corresponding to 1 / 4 of the wavelength of the light to incident light and transmits the incident light.

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

3. The virtual image display device according to claim 1 or 2, wherein: The second polarization layer, the first wavelength layer, the reflection layer, and the second wavelength layer are arranged in this order between the first lens and the second lens toward the first side.

4. The virtual image display device according to claim 3, wherein: The first wavelength layer is provided on the reflective layer, The first wavelength layer comprises: a first orientation film; a first birefringent material disposed between the first orientation film and the reflective layer in the first direction and oriented along the light distribution direction of the first orientation film; and a first sealing member that seals the first birefringent material together with the first alignment film.

5. The virtual image display device according to claim 4, wherein: The second wavelength layer is provided on the incident surface of the second lens. The second wavelength layer comprises: a second orientation film; a second birefringent material provided between the second orientation film and the second incident surface of the second lens in the first direction and oriented along the light distribution direction of the second orientation film; and a second sealing member that seals the second birefringent material together with the second alignment film.

6. The virtual image display device according to claim 1 or 2, wherein: The first polarizing layer includes a first wire grid polarizer and a first base film. The first wire grid polarizer is provided between the second output surface of the second lens and the first base film in the first direction.

7. The virtual image display device according to claim 1 or 2, wherein: The second polarizing layer includes a second wire grid polarizer and a second base film. The second wire grid polarizer is provided between the first output surface of the first lens and the second base film in the first direction.

8. The virtual image display device according to claim 1 or 2, wherein: The second polarization layer, the first wavelength layer, and the reflection layer are arranged in this order between the first lens and the second lens toward the first side. The second wavelength layer is arranged between the second lens and the first polarization layer in the first direction.

9. The virtual image display device according to claim 1 or 2, wherein: The second polarizing layer is arranged between the display element and the first lens. The first wavelength layer and the reflective layer are arranged in this order between the first lens and the second lens.

10. The virtual image display device according to claim 1 or 2, wherein: The first polarizing layer is provided on the second output surface of the second lens.

11. The virtual image display device according to claim 1 or 2, wherein: The second wavelength layer is provided on the second incident surface of the second lens.

12. The virtual image display device according to claim 1 or 2, wherein: The first wavelength layer is provided on the first emission surface of the first lens.

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