Virtual image display device and optical unit

Abstract

To enhance light utilization efficiency.SOLUTION: A virtual image display device 100A, 100B or an optical unit 100 comprises: a first display device 10 that emits video light ML of circularly polarized light; a first reflection member R1 having a flat surface and reflecting the video light ML in an oblique direction; and a second reflection member R2 having positive power and reflecting, toward the first reflection member R1, the video light ML reflected at the first reflection member R1. The first reflection member R1 includes a first optical function layer F1, which is one of a cholesteric liquid crystal layer 56 and a transmissive reflection layer 45. The second reflection member R2 includes a second optical function layer F2, which is the other one of the cholesteric liquid crystal layer 56 and the transmissive reflection layer 45. Thus, the cholesteric liquid crystal layer 56 can efficiently reflect the video light ML, or the cholesteric liquid crystal layer 56 can efficiently reflect and transmit the video light ML, while changing the direction of the circularly polarized light by the transmissive reflection layer 45.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a see-through type virtual image display device and an optical unit that enable viewing of a virtual image. [Background technology]

[0002] A folding optical system for a near-eye display is known that includes, in order from the display, a circular polarizer, a partial reflector, and a reflective polarizer, where the reflective polarizer is, for example, a reflective CLC circular polarizer (see Patent Document 1). In this optical system, the light from the display becomes, for example, left-handed circularly polarized light after passing through the circular polarizer, and the polarization state is maintained even after passing through the partial reflector, and is reflected by the reflective polarizer, but it remains left-handed circularly polarized light, reaches the partial reflector, and is partially reflected. The left-handed circularly polarized light reflected by the partial reflector becomes right-handed circularly polarized light, and passes through the reflective polarizer as it is. Here, the light from the display is double-reflected in the cavity formed by the partial reflector and the reflective polarizer, so that the optical path length can be increased while preventing an increase in the total physical length. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2021-532393 Summary of the Invention [Problem to be solved by the invention]

[0004] In the virtual image display device of Patent Document 1, the display is placed in front of the eyes, so that the light from the surrounding environment is blocked by the display, which is a problem. In the case of a birdbath type virtual image display device that combines a concave half mirror and a flat half mirror, the above-mentioned light blocking by the display is not a problem, but the light utilization efficiency is low and image light is likely to leak to the outside world. [Means for solving the problem]

[0005] A virtual image display device according to one aspect of the present invention comprises a display that emits circularly polarized image light, a planar first reflective member that reflects the image light in an oblique direction, and a second reflective member that has positive power and reflects the image light reflected by the first reflective member toward the first reflective member, wherein the first reflective member includes a first optical functional layer which is one of a cholesteric liquid crystal layer and a transmissive reflective layer, and the second reflective member includes a second optical functional layer which is the other of the cholesteric liquid crystal layer and the transmissive reflective layer. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 is an external view illustrating a state in which the virtual image display device according to a first embodiment is used. [Diagram 2] FIG. 4 is a side cross-sectional view illustrating the internal structure of one of the display devices. [Diagram 3] FIG. 2 is a perspective view illustrating the external structure of a first display optical system. [Figure 4] 3 is a conceptual diagram illustrating the polarization state of image light, etc. in the device shown in FIG. 2. [Diagram 5] 3 is a diagram illustrating a modification of the first display unit of the device shown in FIG. 2. FIG. [Figure 6] FIG. 3 is a diagram illustrating another modified example of the device shown in FIG. [Figure 7] FIG. 11 is a side cross-sectional view illustrating a virtual image display device according to a second embodiment. [Figure 8] 8 is a conceptual diagram illustrating the polarization state of image light and the like in the device shown in FIG. 7. [Figure 9] FIG. 11 is a side cross-sectional view illustrating a virtual image display device according to a third embodiment. [Figure 10] 10 is a conceptual diagram illustrating the polarization state of image light and the like in the device shown in FIG. [Figure 11] FIG. 10 is a diagram illustrating a modified example of the device shown in FIG. [Figure 12] FIG. 13 is a side cross-sectional view illustrating a virtual image display device according to a fourth embodiment. [Figure 13] 13 is a conceptual diagram illustrating the polarization state of image light and the like in the device shown in FIG. 12. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] [First embodiment] Hereinafter, a first embodiment of a virtual image display device etc. according to the present invention will be described with reference to FIGS.

[0008] Fig. 1 is a diagram for explaining the wearing state of a head mounted virtual image display device (hereinafter also referred to as a head mounted display or HMD) 200, in which the observer or wearer US wearing the HMD 200 recognizes an image as a virtual image. In Fig. 1 etc., X, Y, and Z are an orthogonal coordinate system, the +X direction corresponds to the lateral direction in which the eyes EY of the observer or wearer US wearing the HMD 200 are aligned, the +Y direction corresponds to the upward direction perpendicular to the lateral direction in which the eyes EY are aligned for the wearer US, and the +Z direction corresponds to the forward direction or front direction for the wearer US. The ±Y directions are parallel to the vertical axis or vertical direction.

[0009] The HMD 200 includes a first virtual image display device 100A for the right eye and a direct virtual image type, a second virtual image display device 100B for the left eye and a direct virtual image type, a pair of temple-shaped support devices 100C that support the virtual image display devices 100A and 100B, and a user terminal 90 that is an information terminal. The first virtual image display device 100A functions as an HMD alone and is composed of a first display drive unit 102a arranged at the top and a first combiner 103a that is shaped like a pair of glasses and covers the front of the eyes. The second virtual image display device 100B also functions as an HMD alone and is composed of a second display drive unit 102b arranged at the top and a second combiner 103b that is shaped like a pair of glasses and covers the front of the eyes. The support device 100C is a mounting member that is mounted on the head of the wearer US, and supports the upper ends of the pair of combiners 103a and 103b via the display drive units 102a and 102b that are integrated in appearance. The first virtual image display device 100A and the second virtual image display device 100B are optically identical or are left-right inverted versions of each other, and a detailed description of the second virtual image display device 100B will be omitted.

[0010] FIG. 2 is a side cross-sectional view illustrating the internal structure of the first virtual image display device 100A. The first virtual image display device 100A includes a first display 10a, a first display optical system 20a, and a first circuit member 80a. The first display 10a emits circularly polarized image light ML. The first display optical system 20a is an imaging optical system IS that directly forms a virtual image without forming an intermediate image, and is also called a direct virtual image optical system DIS. The imaging optical system IS includes a first coupling lens 30, a first flat-plate member 40, and a second flat-plate member 50. The first coupling lens 30 functions as a protective glass that protects the first display 10a. The first flat-plate member 40 guides the image light ML emitted from the first display 10a to the first lens 53 of the second flat-plate member 50. The second plate-shaped member 50 reflects the image light ML from the first plate-shaped member 40 toward the pupil position PP or the eye EY so as to return the image light ML from the first plate-shaped member 40 to the first plate-shaped member 40, and also allows external light to be incident on the pupil position PP via the first plate-shaped member 40. The first coupling lens 30, the first plate-shaped member 40, and the second plate-shaped member 50 each function as a lens having a positive power.

[0011] Although detailed description will be omitted, the second virtual image display device 100B includes a second display 10b, a second display optical system 20b, and a second circuit member 80b. The second display 10b is similar to the first display 10a, the second display optical system 20b is similar to the first display optical system 20a, and the second circuit member 80b is similar to the first circuit member 80a. The second display optical system 20b includes a first coupling lens 30, a first flat-plate member 40, and a second flat-plate member 50.

[0012] In the first virtual image display device 100A, the first display 10a emits circularly polarized image light ML to the first flat plate-like member 40 via the first coupling lens 30. The first display 10a is housed and supported together with the first circuit member 80a in the case 71. The first display 10a has a display element 11a that emits image light ML including polarized light in one or two directions, a polarizing plate 11b arranged opposite the display element 11a, and a ¼ wavelength plate 11c arranged opposite the polarizing plate 11b to the opposite side of the display element 11a.

[0013] The display element 11a is a self-luminous image light generating device. The display element 11a is, for example, an organic EL (organic electroluminescence) display, and forms a color still image or moving image on a two-dimensional display surface 11d. The display element 11a is driven by the first circuit member 80a to perform a display operation. The display element 11a is not limited to an organic EL display, and can be replaced with a display device using an inorganic EL, an organic LED, an LED array, a laser array, a quantum dot light emitting element, or the like. The display element 11a is not limited to a self-luminous image light generating device, and may be a light modulation element such as a digital micromirror device. In this case, the light modulation element is illuminated by a light source such as a backlight to form an image. In the first virtual image display device 100A, an optical device excluding the first circuit member 80a is called an optical unit 100. The optical unit 100 includes a direct virtual image type optical system, and can be said to be a part corresponding to the direct virtual image optical system DIS constituting the first virtual image display device 100A.

[0014] The polarizing plate 11b limits the polarization direction of the image light ML emitted from the display element 11a to, for example, the D1 direction parallel to the YZ plane. The fast axis or slow axis of the quarter-wave plate 11c is set, for example, in an intermediate direction between the D1 direction and the D2 direction perpendicular to the optical axis AX, and converts the linearly polarized light that has passed through the polarizing plate 11b into right-handed circularly polarized light c1. Here, when focusing on the vibration of the electric field component or magnetic field component of the image light ML, the vibration direction rotates at the frequency of the image light ML in a plane perpendicular to the traveling direction of the light, and the amplitude is constant regardless of the direction. Right-handed circularly polarized light is light in which the vibration direction of the electric field component rotates clockwise as viewed from an observer standing facing the direction in which the light beam travels, and left-handed circularly polarized light is light in the counterclockwise direction. However, in this specification, if the image light ML mainly contains right-handed circularly polarized light, even if it contains linearly polarized light in a specific direction, such image light ML is considered to be right-handed circularly polarized light c1.

[0015] When the display element 11a emits only light polarized in the D1 direction as the image light ML, the polarizing plate 11b can be omitted. Specifically, when the display element 11a is a light modulation element such as an LCD, a polarizer is provided at the light emission portion of the display element 11a, and therefore the polarizing plate 11b is not necessary. When LCOS (Liquid crystal on silicon, LCoS is a registered trademark) is used as the display element 11a instead of an LCD, the polarizing plate 11b is also not necessary. Similarly, when the display element 11a is a laser array or the like that emits only light polarized in the D1 direction as the image light ML, the polarizing plate 11b is also not necessary.

[0016] The first display unit 20a includes a first coupling lens 30, a first flat plate member 40, and a second flat plate member 50. The first flat plate member 40 includes a transmissive reflective layer 45 as a first functional layer F1 of the first reflecting member R1, and the second flat plate member 50 includes a cholesteric liquid crystal layer 56 as a second functional layer F2 of the second reflecting member R2. In the first display unit 20a, the first coupling lens 30 has a positive power, and the image light ML from the first display unit 10a is incident on the first coupling lens 30. The first coupling lens 30 has a flat light entrance surface 30f bonded to the first display unit 10a, and a convex light exit surface 30g. The light exit surface 30g is, for example, a spherical surface, but can be an aspheric surface having an axisymmetric shape. The first coupling lens 30 can be considered as being divided into a parallel plate 31 and a lens portion 32. By ensuring that the thickness of the parallel plate 31 is equal to or greater than a predetermined value, foreign matter attached to the surface of the first coupling lens 30 becomes less noticeable. The lens portion 32 is a plano-convex lens. The first coupling lens 30 is made of, for example, fused quartz, and has a relatively low refractive index.

[0017] The first flat-plate member 40 has a first prism 41 having a parallel flat plate shape, a second prism 42 having a parallel flat plate shape, and a transmissive reflective layer 45 disposed between them. The first prism 41 and the second prism 42 are joined at the inclined surfaces 41d and 42d. The first prism 41 and the second prism 42 joined together are called a prism light-guiding member 48. The prism light-guiding member 48 has the appearance of a parallel flat plate. A flat transmissive reflective layer 45 is formed on the inclined surface 41d formed on the lower side of the first prism 41. The combination of the prism light-guiding member 48 and a second flat-plate member 50 described later corresponds to the first combiner 103a in FIG. 1.

[0018] The first prism 41 has a quadrangular prism-like outer shape and a trapezoidal cross section. The first prism 41 guides the image light ML and has an incident optical surface 41a, an inner surface 41b, an outer surface 41c, and an inclined surface 41d. Here, the incident optical surface 41a is generally inclined downward in the front. The optical axis AX passing through the incident optical surface 41a extends in a direction between the rearward -Z direction and the downward -Y direction. This makes it easier to arrange the first display 10a closer to the outside world side than the inner surface 41b, and the angle at which the image light ML propagates in the first prism 41 can be adjusted. The incident optical surface 41a is a convex surface, and is, for example, a spherical surface, but can be an axially symmetric aspheric surface. The first prism 41 can be considered to have a second coupling lens 44 including the incident optical surface 41a. The second coupling lens 44 is a convex-flat lens having a positive power. The inner surface 41b and the outer surface 41c are parallel to each other and extend perpendicular to the optical axis AX between the pupil position PP. The inner surface 41b and the outer surface 41c internally reflect the image light ML (i.e., reflect it inside the object surface), and it is particularly preferable that they totally reflect the image light ML. The inner surface 41b can be hard-coated to improve scratch resistance or abrasion resistance. The inclined surface 41d is a flat surface. The inclined surface 41d forms an acute angle with the outer surface 41c, specifically an angle of 25° to 32°. The distance between the optical axis AX passing through the pupil position PP and the upper end of the first coupling lens 30 is about 20 mm. The first prism 41 is made of a resin material and has a refractive index higher than that of the first coupling lens 30.

[0019] The second coupling lens 44 may be omitted. That is, the incident optical surface 41a may be a flat surface.

[0020] The image light ML is reflected once by the inner surface 41b, once by the outer surface 41c, and once by the transmissive reflective layer 45 described below. By making the number of internal reflections of the image light ML in the first prism 41 two, it is possible to prevent light that has been reflected a different number of times within the first prism 41 from being mixed while increasing the angle of view and pupil position PP or the aperture PPa of the image light ML. The image light ML reflected by the inner surface 41b and the outer surface 41c is less divergent than the initial divergent state emitted from the first display 10a, i.e., the display element 11a, because no intermediate image is formed in the first display unit 20a or the imaging optical system IS. However, the image light ML enters the inner surface 41b and the outer surface 41c in a divergent state, and the divergent state is maintained.

[0021] The second prism 42, like the first prism 41, has a quadrangular prism-like outer shape and a trapezoidal cross section. The second prism 42 transmits the image light ML and has an inner surface 42b, an outer surface 42c, and an inclined surface 42d. Here, the inner surface 42b and the outer surface 42c are parallel to each other and extend perpendicular to the optical axis AX between the pupil position PP. The inner surface 42b can be hard-coated to improve scratch resistance. The second prism 42 is made of a resin material and has a refractive index equal to that of the first prism 41.

[0022] The transmissive reflective layer 45 is a flat first reflecting member R1 that reflects the image light ML in an oblique direction. The transmissive reflective layer 45 is integrally formed on the inclined surface 41d of the first prism 41 and is sandwiched between the inclined surface 41d of the first prism 41 and the inclined surface 42d of the second prism 42. In other words, the transmissive reflective layer 45 is provided at the joint between the first prism 41 and the second prism 42. The space between the transmissive reflective layer 45 and the inclined surface 42d is filled with a bonding adhesive CT. The transmissive reflective layer 45 is formed of a single layer or multilayer film of a metal such as Al or Ag, whose thickness is adjusted. The transmissive reflective layer 45 is formed by lamination using deposition, for example. The transmissive reflective layer 45 may be a dielectric multilayer film made of a plurality of dielectric layers whose thickness is adjusted. The reflectance of the transmissive reflective layer 45 for the image light ML and the external light OL is set to, for example, 50% or more within the expected range of incident angles of the image light ML, from the standpoint of ensuring the brightness of the image light ML and facilitating observation of the external world image through see-through.

[0023] If the reflection angle of the image light ML on the optical axis AX in the first prism 41 is β0, then the inclination angle θ of the transmissive reflective layer 45 is θ=β0 / 2. If the maximum reflection angle of the image light ML is βmax, assuming that the transmissive reflective layer 45 does not obstruct the path of the image light ML, then it is desirable that the inclination angle θ of the transmissive reflective layer 45 is smaller than 90°-βmax. The reflection angle β0 of the image light ML corresponds to the angle between the normal to the inner surface 41b and the optical axis AX passing through the incident optical surface 41a.

[0024] The second flat member 50 has a plano-convex first lens 53, a plano-convex second lens 54, a compensation plate 55 arranged around the second lens 54, and a cholesteric liquid crystal layer 56 arranged so as to be sandwiched between the first lens 53 and the second lens 54.

[0025] The second flat plate-like member 50 is disposed at a distance of, for example, about 20 μm to 50 μm from the first flat plate-like member 40. By setting the distance between the outer side surfaces 41c, 42c and the inner side surface 50c to 20 μm or more, more preferably 30 μm or more, it is possible to prevent these surfaces from being excessively close to each other. Conversely, by setting the distance between the outer side surfaces 41c, 42c and the inner side surface 50c to 50 μm or less, it is possible to prevent the thickness of the first combiner 103a obtained by combining the first flat plate-like member 40 and the second flat plate-like member 50 from increasing. Between the outer side surfaces 41c, 42c of the first flat plate-like member 40 and the inner side surface 50c of the second flat plate-like member 50, a spacer 61 is provided for adjusting the distance between the first flat plate-like member 40 and the second flat plate-like member 50 and fixing them in a mutually positioned state. The spacer 61 is not provided around the entire circumference of the second flat plate-like member 50. In other words, the gap SP between the first flat plate member 40 and the second flat plate member 50 is not sealed and is in communication with the outside world.

[0026] The first lens 53 is thin but has positive power, and has a flat surface 53f facing the outer surfaces 41c, 42c of the first flat-plate member 40, and a convex surface 53g facing the second lens 54. The convex surface 53g is, for example, a spherical surface, but can be an aspheric surface having axial symmetry. The second lens 54 is thin but has negative power, and has a concave surface 54f facing the first lens 53, and a flat surface 54g. The compensation plate 55 is a parallel plate and has a pair of flat surfaces 55f, 55g. Here, the concave surface 54f of the second lens 54 has the same shape as the convex surface 53g of the first lens 53. The flat surface 53f of the first lens 53 and the flat surface 55f of the compensation plate 55 are on the same plane. The flat surface 54g of the second lens 54 and the flat surface 55g of the compensation plate 55 are on the same plane and are continuous. Cholesteric liquid crystal layer 56 is a thin film formed on convex surface 53g of first lens 53, and has the same shape as convex surface 53g. The combination of first lens 53 and cholesteric liquid crystal layer 56 is called a light-collecting reflector CR.

[0027] The first lens 53, the second lens 54, and the compensation plate 55 are made of a resin material and have the same refractive index. The refractive index of the first lens 53, etc. is lower than that of the first prism 41. The second lens 54 and the compensation plate 55 are an optical element 58 integrally formed from the same resin material. The combination of the first lens 53, the second lens 54, and the compensation plate 55 functions as a parallel plate as a whole. In other words, the outside light OL incident on the position of the second lens 54 or the compensation plate 55 passes through them without being affected by the lens action of the second lens 54, etc., or the step existing on the outer edge of the second lens 54. The flat surfaces 54g, 55g of the second lens 54 and the compensation plate 55 may be coated with an anti-reflection film or a hard coat. The outside light OL passing through the compensation plate 55 is incident on the second flat-plate member 50 from the top, bottom, left, and right of the second lens 54, that is, from the surrounding area outside the incident area of ​​the image light ML. This ensures a wide see-through field of view with respect to the outside world. The viewing range of the outside light OL is set to, for example, about 40° upward and about 40° downward.

[0028] The diameter of the first lens 53 is set to 20 mm to 25 mm in order to ensure the angle of view. The thickness in the Z direction of the first flat plate member 40 or the prism light-guiding member 48 is 6 mm to 8 mm, and the distance from the inner sides 41b, 42b of the first flat plate member 40 to the pupil position PP is about 12 mm to 13 mm, so that the angle of view (diagonal), which is the angular range in which the image light ML is incident on the pupil position PP, can be set to about 40°.

[0029] The cholesteric liquid crystal layer 56 is the second reflecting member R2 or a part thereof that reflects the image light ML reflected by the transmissive reflecting layer 45, which is the first reflecting member R1, toward the transmissive reflecting layer 45. The cholesteric liquid crystal layer 56 selectively reflects the image light ML that has been reflected by the transmissive reflecting layer 45 and turned into left-handed circularly polarized light c2 while maintaining the left-handed circularly polarized light c2. That is, the cholesteric liquid crystal layer 56 transmits almost no image light ML and prevents the image light ML from being emitted to the outside world. On the other hand, since the outside light OL includes right-handed circularly polarized light and left-handed circularly polarized light, the cholesteric liquid crystal layer 56 transmits right-handed circularly polarized light. That is, the cholesteric liquid crystal layer 56 partially transmits the outside light OL. The cholesteric liquid crystal layer 56 reflects the image light ML that has been reflected by the transmissive reflecting layer 45 of the first flat plate-like member 40 and passed through the first lens 53 toward the pupil position PP. The image light ML reflected by the cholesteric liquid crystal layer 56 is partially transmitted through the transmissive reflective layer 45 of the prism light-guiding member 48 and enters the pupil position PP. The cholesteric liquid crystal layer 56 is a concave mirror that covers the pupil position PP where the eye EY or pupil is located and has a concave shape toward the pupil position PP and a convex shape toward the outside world. The pupil position PP or its opening PPa is called the eye point or eye box, and corresponds to the exit pupil EP of the first display unit 20a.

[0030] The cholesteric liquid crystal layer 56 transmits a portion of the outside light OL, enabling a see-through view of the outside world and allowing a virtual image to be superimposed on an image of the outside world. At this time, the outside light OL passes through the first flat plate-like member 40 and the second flat plate-like member 50, but the flat plate-like members 40, 50 do not act as a lens on the outside light OL.

[0031] The cholesteric liquid crystal layer 56 has a layered structure of molecules oriented in a certain direction, and the molecular orientation axis is twisted between adjacent layers, so that the orientation direction is a helical structure around the vertical axis of the layer as a whole. The cholesteric liquid crystal layer 56 is made of a specific liquid crystal material and has the property of transmitting right-handed circularly polarized light c1 and reflecting left-handed circularly polarized light c2. The cholesteric liquid crystal layer 56 is formed by sandwiching a liquid crystal material containing a liquid crystal material and an additive between the first lens 53 and the second lens 54, and by irradiating the liquid crystal material sandwiched between the first lens 53 and the second lens 54 with UV light or the like, by removing or vaporizing the solvent from the liquid crystal material sandwiched between the first lens 53 and the second lens 54 while the first lens 53 and the second lens 54 are relatively fixed, the liquid crystal material layer becomes a liquid crystal material layer in a stable state with reduced fluidity. The cholesteric liquid crystal layer 56 may be solidified on one surface of the first lens 53 and the second lens 54, for example, and may be sandwiched by attaching the other surface of the first lens 53 and the second lens 54. The cholesteric liquid crystal layer 56 may be produced by applying the methods described in JP-A-2008-501147 and JP-A-2021-532393.

[0032] In the first virtual image display device 100A, the first coupling lens 30, the second coupling lens 44, the first lens 53, and the cholesteric liquid crystal layer 56 each have a positive power and tend to converge divergent light. The first coupling lens 30, the second coupling lens 44, the first lens 53, and the cholesteric liquid crystal layer 56, including the main body of the first prism 41 and the second prism 42, function as an imaging optical system IS like a simple microscope type microscope that forms an erect image, or a direct virtual image optical system DIS. This makes it possible to form a virtual image by projecting a real image formed on the display surface 11d of the display element 11a, for example, at infinity, or to form a virtual image by projecting a real image formed on the display surface 11d several meters away. At this time, by adjusting the refractive power or power of the first coupling lens 30, the second coupling lens 44, the first lens 53, and the cholesteric liquid crystal layer 56, the focal length of the imaging optical system IS can be shortened to achieve a desired magnification ratio.

[0033] 3, the size in the vertical and horizontal directions, i.e., the XY directions, of the first flat plate member 40 or the second flat plate member 50 is, for example, about 34 mm×40 mm, and the thickness in the front-to-rear direction of the first flat plate member 40 and the second flat plate member 50 combined is suppressed to about 7.5 mm. The size of the width and depth of the display element 11a and the first coupled lens 30 is, for example, about 7 mm×14 mm.

[0034] In the first flat plate-like member 40, upper flat surfaces 40u are provided on the left and right of the incident optical surface 41a. No light is incident on the upper flat surface 40u. In order to prevent stray light, a light shielding body (not shown) may be disposed facing and covering the upper flat surface 40u, or a light shielding body may be applied to the upper flat surface 40u. A light shielding body or the like may be provided to cover the lateral flat surface 40v and the lower flat surface 40w. A light shielding body or the like may be provided around the periphery of the second flat plate-like member 50 to cover it.

[0035] The radius of curvature of the convex light exit surface 30g of the first coupling lens 30 is, for example, 20 mm. Additionally, the radius of curvature of the incident optical surface 41a of the first prism 41 is, for example, 14 mm, and the radius of curvature of the cholesteric liquid crystal layer 56 is, for example, 47 mm.

[0036] Regarding the optical path, referring to FIG. 2 etc., the image light ML emitted from the first display 10a is a right-handed circularly polarized light c1, and enters the first prism 41 through the first coupling lens 30. At this time, the degree of divergence of the image light ML is suppressed by the positive power of the first coupling lens 30 and the second coupling lens 44. In the optical path passing through the first prism 41, the image light ML is sequentially reflected by the inner surface 41b and the outer surface 41c of the first prism 41 without forming an intermediate image, and a part of the image light ML is reflected by the transmissive reflective layer 45. The image light ML reflected by the transmissive reflective layer 45 is a left-handed circularly polarized light c2. The image light ML reflected by the transmissive reflective layer 45 passes through the outer surface 41c of the first prism 41 and enters the cholesteric liquid crystal layer 56 through the first lens 53. The left-handed circularly polarized light c2 incident on the cholesteric liquid crystal layer 56 is almost entirely reflected by the cholesteric liquid crystal layer 56, collimated through the first lens 53, incident on the first prism 41 from the outer surface 41c, partially transmitted through the transmissive reflective layer 45, and emitted outside the second prism 42 through the inner surface 42b. The image light ML emitted outside the second prism 42 is incident on a pupil position PP where the eye EY or pupil of the wearer US is located. Not only the image light ML reflected by the cholesteric liquid crystal layer 56, but also the outside light OL transmitted through the cholesteric liquid crystal layer 56 and the outside light OL passed through the compensation plate 55 are incident on the pupil position PP. That is, the wearer US wearing the first virtual image display device 100A can observe a virtual image by the image light ML superimposed on an outside image.

[0037] Referring to FIG. 4, the image light ML from the first display 10a is right-handed circularly polarized light, and is reflected by the inner surface 41b and the outer surface 41c of the first prism 41 to enter the transmissive reflective layer 45 in a right-handed circularly polarized state. The image light ML reflected by the transmissive reflective layer 45 is converted from right-handed circularly polarized light to left-handed circularly polarized light, and enters the cholesteric liquid crystal layer 56 via the outer surface 41c and the like. The image light ML reflected by the cholesteric liquid crystal layer 56 is maintained as left-handed circularly polarized light, and passes through the outer surface 41c, the transmissive reflective layer 45, and the inner surface 42b as left-handed circularly polarized light. In the above, the cholesteric liquid crystal layer 56 reflects most of the image light ML, which is left-handed circularly polarized light, so that the image light ML is almost completely blocked by the second flat plate-like member 50 and does not leak out to the outside. In other words, the image light ML can be prevented from being observed from the outside, so privacy can be ensured.

[0038] Regarding the outside light OL, right-handed circularly polarized light selectively passes through the cholesteric liquid crystal layer 56, and passes through the outer surface 41c, the transmissive reflective layer 45, and the inner surface 42b as right-handed circularly polarized light.

[0039] In the above, it is assumed that the transmissive reflective layer 45 is set to a reflectance of, for example, 50%. In this case, the image light ML emitted from the display element 11a is attenuated to, for example, 50% by the polarizer 11b, and is further attenuated to 25% by the transmissive reflective layer 45, but even when reflected by the cholesteric liquid crystal layer 56, it is maintained at 25% based on the original display element 11a. The intensity of the image light ML passing through the transmissive reflective layer 45 and incident on the pupil position PP is 12.5% ​​based on the original display element 11a. The outside light OL is maintained at the original 50%.

[0040] The first display 10a is not limited to one that emits image light ML of a specific wavelength, but may be one that emits colored image light ML. In this case, it is preferable that the cholesteric liquid crystal layer 56 also corresponds to the visible band. In order to make the cholesteric liquid crystal layer 56 compatible with a plurality of wavelengths, it may have a multi-layer structure including element layers corresponding to each color of RGB, for example.

[0041] Fig. 5 is a diagram illustrating a modified example of the first display 10a shown in Fig. 2. In this case, the first display 10a has a display element 11a that emits image light ML including polarized light in one or two directions, and a cholesteric liquid crystal element 111r arranged opposite the display element 11a. The cholesteric liquid crystal element 111r selectively passes only a right-handed circularly polarized light component c1 of the image light ML emitted from the display element 11a. In other words, only the right-handed circularly polarized light c1 is emitted from the first display 10a as the image light ML.

[0042] 6 is a diagram illustrating another modified example of the first display 10a shown in FIG. 2. In this case, the image light ML emitted from the first display 10a is left-handed circularly polarized light, and the cholesteric liquid crystal layer 156 transmits the left-handed circularly polarized light and reflects the right-handed circularly polarized light. In this case, the image light ML is almost completely blocked by the second flat plate member 50 or the cholesteric liquid crystal layer 56, and the image light ML does not leak out. On the other hand, since the second flat plate member 50 transmits the outside light OL, the wearer US can observe a virtual image by the image light ML superimposed on an outside image.

[0043] The virtual image display device 100A, 100B or optical unit 100 of the first embodiment described above comprises a first display device 10 that emits circularly polarized image light ML, a planar first reflecting member R1 that reflects the image light ML in an oblique direction, and a second reflecting member R2 that has positive power and reflects the image light ML reflected by the first reflecting member R1 toward the first reflecting member R1, where the first reflecting member R1 includes a first optical functional layer F1 which is one of the cholesteric liquid crystal layer 56 and the transmissive reflective layer 45, and the second reflecting member R2 includes a second optical functional layer F2 which is the other of the cholesteric liquid crystal layer 56 and the transmissive reflective layer 45.

[0044] In the above virtual image display device, the first reflecting member R1 reflects the image light ML in an oblique direction, so that an optical arrangement in which the display 10a is placed in front of the eyes can be avoided. In the present virtual image display devices 100A and 100B, one of the first reflecting member R1 and the second reflecting member R2 includes a cholesteric liquid crystal layer 56, and the other of the first reflecting member R1 and the second reflecting member R2 includes a transmissive reflecting layer 45. Therefore, the image light ML can be efficiently reflected by the cholesteric liquid crystal layer 56 while the direction of the circularly polarized light is switched by the transmissive reflecting layer 45, and the light utilization efficiency can be easily improved.

[0045] In the virtual image display devices 100A and 100B of the first embodiment, the first reflecting member R1 includes a transmissive reflecting layer 45 as the first optical functional layer F1, and the second reflecting member R2 includes a cholesteric liquid crystal layer 56 as the second optical functional layer F2. In this case, most of the circularly polarized light reflected by the transmissive reflecting layer 45 of the first reflecting member R1 is reflected by the cholesteric liquid crystal layer 56 of the second reflecting member R2, so that it is possible to prevent the image light ML from leaking out to the outside world.

[0046] Second Embodiment Hereinafter, the virtual image display device etc. of the second embodiment will be described. Note that the virtual image display device of the second embodiment is a partial modification of the virtual image display device of the first embodiment, and the description of the parts common to the virtual image display device of the first embodiment will be omitted.

[0047] In the virtual image display device 100A or the optical unit 100 shown in FIG. 7, a cholesteric liquid crystal layer 245 is used as the first optical functional layer F1 of the first reflecting member R1, and a transmissive reflective layer 256 is used as the second optical functional layer F2 of the second reflecting member R2. The cholesteric liquid crystal layer 245, which is the first optical functional layer F1, is similar to the cholesteric liquid crystal layer 56 shown in FIG. 2. The transmissive reflective layer 256, which is the second optical functional layer F2, is similar to the transmissive reflective layer 45 shown in FIG. 2. In other words, compared to the first embodiment, the arrangement of the cholesteric liquid crystal layer 245 and the transmissive reflective layer 256 is interchanged.

[0048] 8, the image light ML from the first display 10a is left-handed circularly polarized light, and is reflected by the inner surface 41b and the outer surface 41c of the first prism 41 to enter the first optical functional layer F1, i.e., the cholesteric liquid crystal layer 245 in a left-handed circularly polarized state, and is mostly reflected. The image light ML reflected by the cholesteric liquid crystal layer 245 is maintained in a left-handed circularly polarized state, and enters the transmissive reflective layer 256, which is the second optical functional layer F2, through the outer surface 41c, etc. The image light ML reflected by the transmissive reflective layer 256 is converted from left-handed circularly polarized light to right-handed circularly polarized light, and passes through the outer surface 41c, the cholesteric liquid crystal layer 245, and the inner surface 42b while remaining as right-handed circularly polarized light. In the above, the cholesteric liquid crystal layer 245 reflects most of the image light ML, which is left-handed circularly polarized light, and transmits most of the image light ML, which is right-handed circularly polarized light.

[0049] The external light OL partially passes through the transmissive reflective layer 256. The external light OL that has partially passed through the transmissive reflective layer 256 is incident on the cholesteric liquid crystal layer 245 via the outer surface 41c etc., and only the right-handed circularly polarized component of the external light OL selectively passes through the cholesteric liquid crystal layer 245 and passes through the inner surface 42b as right-handed circularly polarized light.

[0050] In the above, it is assumed that the transmissive reflective layer 256 is set to a reflectance of, for example, 50%. In this case, the image light ML emitted from the display element 11a is attenuated to, for example, 50% by the polarizing plate 11b, but even when reflected by the cholesteric liquid crystal layer 245, the intensity is maintained at 50% based on the original display element 11a. The image light ML reflected by the cholesteric liquid crystal layer 245 is attenuated to 25% by reflection by the transmissive reflective layer 256, so that the intensity of the image light ML passing through the cholesteric liquid crystal layer 245 and incident on the pupil position PP is 25% based on the original display element 11a. The outside light OL is maintained at the original 50%.

[0051] In the first display 10a, the polarizer 11b and the quarter-wave plate 11c can be replaced with a cholesteric liquid crystal element 111r shown in FIG.

[0052] The cholesteric liquid crystal layer 245 may reflect right-handed circularly polarized light and transmit left-handed circularly polarized light. In this case, right-handed circularly polarized light is emitted from the first display 10a as the image light ML.

[0053] In the virtual image display devices 100A and 100B of the second embodiment, the first reflecting member R1 includes a cholesteric liquid crystal layer 245 as the first optical functional layer F1, and the second reflecting member R2 includes a transmissive reflecting layer 256 as the second optical functional layer F2. In this case, there is almost no attenuation of the image light ML during reflection and transmission at the cholesteric liquid crystal layer 245. In other words, the image light ML can be efficiently reflected and transmitted by the cholesteric liquid crystal layer 56, and the light utilization efficiency can be improved.

[0054] Third Embodiment Hereinafter, a virtual image display device of the third embodiment will be described. The virtual image display device of the third embodiment is a partially modified version of the virtual image display device of the first embodiment, and a description of parts common to the virtual image display device of the first embodiment will be omitted.

[0055] With reference to FIG. 9, the virtual image display device 100A or the optical unit 100 includes a first display device 10a and a first display optical system 320a.

[0056] The first display optical system 320a is an imaging optical system IS that directly forms a virtual image without forming an intermediate image. The imaging optical system IS includes an inclined mirror 340 that is a first reflecting member R1, and a concave mirror 350 that is a second reflecting member R2.

[0057] The inclined mirror 340, i.e., the first reflecting member R1, includes a first support substrate 40a that is a parallel flat plate and supports the first optical functional layer F1, and is disposed in an inclined state facing the first display 10a. The concave mirror 350, i.e., the second reflecting member R2, includes a second support substrate 50a that is curved and has a uniform thickness and supports the second optical functional layer F2. The first support substrate 40a of the inclined mirror 340 supports a transmissive reflecting layer 345, which is the first optical functional layer F1, on a surface facing the second reflecting member R2. The second support substrate 50a of the concave mirror 350 supports a cholesteric liquid crystal layer 356, which is the second optical functional layer F2, on an inner surface facing the first reflecting member R1.

[0058] Referring to FIG. 10, the image light ML from the first display 10a is right-handed circularly polarized light, and enters the transmissive reflective layer 345 in a right-handed circularly polarized state. The image light ML reflected by the transmissive reflective layer 345 is converted from right-handed circularly polarized light to left-handed circularly polarized light, and enters the cholesteric liquid crystal layer 356. The image light ML reflected by the cholesteric liquid crystal layer 356 is maintained in a left-handed circularly polarized state, and passes through the transmissive reflective layer 345 as left-handed circularly polarized light. In the above, the cholesteric liquid crystal layer 356 reflects most of the image light ML, which is left-handed circularly polarized light, so that the image light ML is almost completely blocked by the concave mirror 350, i.e., the second reflecting member R2, and does not leak out to the outside. In other words, the image light ML can be prevented from being observed from the outside, and privacy can be ensured.

[0059] As for the external light OL, the right-handed circularly polarized component selectively passes through the cholesteric liquid crystal layer 356 and passes through the transmissive reflective layer 345 as it is.

[0060] Fig. 11 is a diagram illustrating a modified example of the virtual image display device 100A or the optical unit 100 shown in Fig. 9. In this case, the second supporting substrate 50a includes a pair of bonded substrate elements 50aa, 50ab, and supports a cholesteric liquid crystal layer 356, which is the second optical functional layer F2, between the pair of substrate elements 50aa, 50ab.

[0061] [Fourth embodiment] Hereinafter, the virtual image display device of the fourth embodiment will be described. The virtual image display device of the fourth embodiment is a partial modification of the virtual image display device of the third embodiment, and the description of the parts common to the virtual image display device of the third embodiment will be omitted.

[0062] With reference to FIG. 12, the virtual image display device 100A or the optical unit 100 includes a first display device 10a and a first display optical system 420a.

[0063] The first display optical system 420a is an imaging optical system IS that directly forms a virtual image without forming an intermediate image. The imaging optical system IS includes an inclined mirror 340 that is a first reflecting member R1, and a concave mirror 350 that is a second reflecting member R2.

[0064] The first support substrate 40a of the inclined mirror 340 supports a cholesteric liquid crystal layer 445, which is the first optical functional layer F1, on a surface facing the second reflecting member R2. The second support substrate 50a of the concave mirror 350 supports a transmissive reflective layer 456, which is the second optical functional layer F2, on an inner surface facing the first reflecting member R1. In other words, compared to the third embodiment, the positions of the cholesteric liquid crystal layer 445 and the transmissive reflective layer 456 are swapped.

[0065] 13, the image light ML from the first display 10a is left-handed circularly polarized light, and enters the first optical functional layer F1, i.e., the cholesteric liquid crystal layer 445 in a left-handed circularly polarized state and is mostly reflected. The image light ML reflected by the cholesteric liquid crystal layer 445 is maintained in a left-handed circularly polarized state and enters the transmissive reflective layer 456, which is the second optical functional layer F2. The image light ML reflected by the transmissive reflective layer 456 is converted from left-handed circularly polarized light to right-handed circularly polarized light, and passes through the cholesteric liquid crystal layer 445 as right-handed circularly polarized light. In the above, the cholesteric liquid crystal layer 445 reflects most of the image light ML, which is left-handed circularly polarized light, and transmits most of the image light ML, which is right-handed circularly polarized light, so that the image light ML is not attenuated by reflection or transmission by the cholesteric liquid crystal layer 445.

[0066] The external light OL partially passes through the transmissive reflective layer 456. The external light OL that has partially passed through the transmissive reflective layer 456 is incident on the cholesteric liquid crystal layer 445, and only the right-handed circularly polarized light component of the external light OL selectively passes through the cholesteric liquid crystal layer 445.

[0067] [Variations and Others] The present invention has been described above based on the embodiments, but the present invention is not limited to the above embodiments and can be embodied in various forms without departing from the spirit of the present invention. For example, the following modifications are also possible.

[0068] In the above, it has been described that the HMD 200 comprises a first virtual image display device 100A and a second virtual image display device 100B, but the HMD 200 may also be configured to support a single first virtual image display device 100A or second display device 100B in front of the eyes by a support device 100C.

[0069] The imaging optical system IS of the virtual image display devices 100A and 100B may form an intermediate image on the optical path from the first display 10a to the second reflecting member R2.

[0070] In the second flat plate member 50, the compensating plate 55 can be omitted. In this case, the first lens 53 is covered by the second lens 54.

[0071] The first imaging lens 30 is not limited to being integrated with the first display 10a, but may be disposed separately from the first display 10a.

[0072] The polarizing plate 11b and the quarter-wave plate 11c may be disposed, for example, after the first imaging lens 30, away from the display element 11a.

[0073] The first display 10a may be a scanning type display having a laser light source and a scanner mirror.

[0074] In a specific embodiment, the virtual image display device comprises a display that emits circularly polarized image light, a planar first reflective member that reflects the image light in an oblique direction, and a second reflective member that has positive power and reflects the image light reflected by the first reflective member toward the first reflective member, where the first reflective member includes a first optical functional layer that is one of a cholesteric liquid crystal layer and a transmissive reflective layer, and the second reflective member includes a second optical functional layer that is the other of the cholesteric liquid crystal layer and the transmissive reflective layer.

[0075] In the virtual image display device, the first reflecting member reflects the image light in an oblique direction, so that an optical arrangement in which a display is placed in front of the eyes can be avoided. In addition, in this virtual image display device, one of the first reflecting member and the second reflecting member includes a cholesteric liquid crystal layer, and the other of the first reflecting member and the second reflecting member includes a transmissive reflective layer, so that the transmissive reflective layer can switch the direction of circularly polarized light while the cholesteric liquid crystal layer can efficiently reflect the image light, or the cholesteric liquid crystal layer can efficiently reflect and transmit the image light, so that the light utilization efficiency can be easily improved.

[0076] In a specific aspect, the first reflecting member includes a transmissive reflective layer as the first optical functional layer, and the second reflecting member includes a cholesteric liquid crystal layer as the second optical functional layer, in which case most of the circularly polarized light reflected by the transmissive reflective layer of the first reflecting member is reflected by the cholesteric liquid crystal layer of the second reflecting member, thereby preventing image light from leaking to the outside.

[0077] In a specific aspect, the present invention includes a first prism into which image light from a display device is incident, and a second prism joined to the first prism to form a parallel plate-like prism light-guiding member, and the first reflecting member is provided at a joint between the first prism and the second prism. In this case, the image light incident on the first prism from the display device and guided in the first prism is reflected in an oblique direction by the first reflecting member, and the image light from the first reflecting member is reflected by the second reflecting member, passes through the prism light-guiding member, and is incident on the pupil position.

[0078] In a specific aspect, the second reflecting member includes a first lens having a plano-convex surface, a planar surface facing the outer surface of the first prism, and a convex surface on the opposite side of the first prism across the planar surface, and a second lens having a concave surface having a shape obtained by inverting the convex surface of the first lens and bonded to the convex surface via the second optical function layer, and a planar surface arranged parallel to the outer surface of the first prism on the opposite side of the first lens across the concave surface. In this case, outside light can be naturally observed through a parallel plate formed by the first lens and the second lens.

[0079] In a specific aspect, the projector includes a coupling lens having a positive refractive power through which image light passes when entering the first prism from the display device. When a virtual image is directly formed without forming an intermediate image, the coupling lens, the first lens, and the second reflecting member can ensure refractive power, and the magnification can be ensured while suppressing an increase in the optical path length, thereby making it possible to avoid an increase in the size of the optical system.

[0080] In a specific aspect, the first reflecting member is in the form of a parallel plate and includes a first support substrate supporting the first optical functional layer, and is disposed in an inclined state facing the display, and the second reflecting member is curved and has a uniform thickness and includes a second support substrate supporting the second optical functional layer. In this case, the first reflecting member is disposed in an inclined state between the second reflecting member and the pupil position, and the image light from the display is reflected in an oblique direction by the first reflecting member, and the image light from the first reflecting member is reflected by the second reflecting member, passes through the first reflecting member, and is incident on the pupil position.

[0081] In a specific aspect, the second supporting substrate supports a second optical functional layer on an inner surface facing the first reflecting member, or includes a pair of bonded substrate elements and supports the second optical functional layer between the pair of substrate elements.

[0082] In a specific aspect, the display device includes a display element that emits image light, a polarizing plate that is disposed opposite the display element, and a quarter-wave plate that is disposed opposite the polarizing plate to the display element, where the display element emits image light that includes polarized light in one or two directions.

[0083] In a specific aspect, the display device includes a display element that emits image light and a cholesteric liquid crystal element that is disposed opposite the display element. Here, the display element is, for example, an organic electroluminescence (EL) element display, and emits image light that includes polarized light in at least one direction.

[0084] In a specific aspect, the display device includes a display element that emits image light polarized in a predetermined direction, and a quarter-wave plate disposed opposite the display element. Here, the display element is, for example, a liquid crystal display, and emits image light polarized in the predetermined direction.

[0085] An optical unit in one aspect of the present invention comprises a display that emits circularly polarized image light, a planar first reflecting member that reflects the image light in an oblique direction, and a second reflecting member that has positive power and reflects the image light reflected by the first reflecting member toward the first reflecting member, wherein the first reflecting member includes a first optical functional layer that is one of a cholesteric liquid crystal layer and a transmissive reflective layer, and the second reflecting member includes a second optical functional layer that is the other of the cholesteric liquid crystal layer and the transmissive reflective layer. [Explanation of symbols]

[0086] 10a...first display, 10b...second display, 11a...display element, 11b...polarizing plate, 11c...quarter-wave plate, 11d...display surface, 20a...first display optical system, 20b...second display optical system, 30...first coupling lens, 31...parallel plate, 32...lens portion, 40...first flat-plate member, 50...second flat-plate member, 41a...entrance optical surface, 41b...inner surface, 41c...outer surface, 41 d, 42d...inclined surface, 42b...inner surface, 42c...outer surface, 44...second coupled lens, 45...transmissive reflective layer, 48...prism light guide member, 50c...inner surface, 53...first lens, 54...second lens, 53f...flat surface, 53g...convex surface, 54f...concave surface, 54g...flat surface, 55...compensating plate, 55f, 55g...flat surface, 56...cholesteric liquid crystal layer, 58...optical element, 61...spe a first virtual image display device, a second virtual image display device, a first optical unit, a second virtual image display device, a first optical unit, a second optical unit, a third optical unit, a fourth optical unit, a fourth optical unit, a fifth optical unit, a fifth optical unit, a sixth optical unit, a fifth optical unit, a sixth optical unit, a seventh optical unit, a eighth ...

Claims

1. A display that emits circularly polarized image light; a first reflecting member having a plane that reflects the image light in an oblique direction; a second reflecting member having a positive power and reflecting the image light reflected by the first reflecting member toward the first reflecting member, The first reflecting member includes a first optical function layer which is one of a cholesteric liquid crystal layer and a transmissive reflecting layer, The second reflecting member includes a second optical function layer which is the other of the cholesteric liquid crystal layer and the transmissive reflective layer. Virtual image display device.

2. The first reflecting member includes the transmissive reflective layer as the first optical function layer, The second reflecting member includes the cholesteric liquid crystal layer as the second optical functional layer. The virtual image display device according to claim 1 .

3. a first prism onto which the image light from the display is incident; a second prism joined to the first prism to form a parallel plate-shaped prism light guide member, The first reflecting member is provided at a joint between the first prism and the second prism. The virtual image display device according to claim 1 .

4. The second reflecting member is a first lens having a plano-convex surface and a convex surface disposed on the opposite side of the first prism from the first prism, the first lens having a planar surface and a convex surface disposed on the opposite side of the first prism from the planar surface; a second lens having a concave surface having a shape obtained by inverting the convex surface of the first lens and bonded to the convex surface via the second optical function layer, and a flat surface disposed parallel to an outer surface of the first prism on the opposite side of the first lens with the concave surface therebetween; The virtual image display device according to claim 3 .

5. a coupling lens having a positive power through which the image light passes when entering the first prism from the display; The virtual image display device according to claim 4 .

6. the first reflecting member is a parallel plate-like member, includes a first supporting substrate supporting the first optical function layer, and is disposed in an inclined state facing the display; The second reflecting member includes a second supporting substrate having a curved and uniform thickness and supporting the second optical function layer. The virtual image display device according to claim 1 .

7. The second support substrate supports the second optical functional layer on an inner surface facing the first reflecting member, or includes a pair of bonded substrate elements and supports the second optical functional layer between the pair of substrate elements. The virtual image display device according to claim 6 .

8. The display device includes a display element that emits the image light, a polarizing plate that is arranged opposite the display element, and a quarter-wave plate that is arranged opposite the polarizing plate to the opposite side of the display element. The virtual image display device according to claim 1 .

9. The display device includes a display element that emits the image light, and a cholesteric liquid crystal element that is disposed opposite to the display element. The virtual image display device according to claim 1 .

10. The display device includes a display element that emits the image light that is polarized in a predetermined direction, and a quarter-wave plate that is disposed opposite the display element. The virtual image display device according to claim 1 .

11. A display that emits circularly polarized image light; a first reflecting member having a plane that reflects the image light in an oblique direction; a second reflecting member having a positive power and reflecting the image light reflected by the first reflecting member toward the first reflecting member, The first reflecting member includes a first optical function layer which is one of a cholesteric liquid crystal layer and a transmissive reflecting layer, The second reflecting member includes a second optical function layer which is the other of the cholesteric liquid crystal layer and the transmissive reflective layer. Optical unit.

Images