Virtual image display device and optical unit

Abstract

To prevent an optical system from being large as a whole.SOLUTION: Virtual image display devices 100A and 100B are direct virtual image type virtual image display devices. The virtual image display device includes: a display element 11; a first lens 30 that has positive refractive power and on which video light ML from the display element 11 is incident; a first prism 41 on which the video light ML passed through the first lens 30 is incident; a second prism 42 that is bonded to the first prism 41 and that forms a prism light-guiding member 48; a polarized light separation film 45 that reflects the video light ML guided in the first prism 41 in accordance with a polarization direction; an angle selection film 60 disposed on an outer surface 48c in the prism light-guiding member 48; a second lens 53 having a plano-convex shape disposed facing the angle selection film; a transmissive mirror 56 that is disposed on a convex surface 53g of the second lens 53 and partially reflects the video light ML; a quarter-wavelength plate 51 disposed between the angle selection film 60 and a flat surface 53f of the second lens 53; and a compensation lens 54 that is bonded to the convex surface 53g.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 head-mounted display comprising a display device, a projection optical member, a prism member, and a collecting reflective surface, in which image light from the projection optical member enters a first prism of the prism member, is totally reflected by the outer surface, is partially reflected by a semi-transmissive reflective surface formed at the boundary between the first and second prisms of the prism member, passes through the outer surface of the prism member and is reflected by the collecting reflective surface, is returned to the prism member, passes through the semi-transmissive reflective surface, and further passes through the inner surface facing the pupil, is known (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-08749 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned head mounted display, an intermediate image is formed in the first prism, which lengthens the optical path and makes the optical system larger overall. Also, since the projection optical member is disposed in a direction inclined toward the face rather than above the prism member, the projection optical member is disposed close to the face, which makes interference more likely to occur, and there are limitations on the arrangement and size of the projection optical member. [Means for solving the problem]

[0005] A virtual image display device according to one aspect of the present invention is a direct virtual image type virtual image display device, comprising: a display element that emits image light; a first lens having positive refractive power and into which the image light from the display element is incident; a first prism into which the image light that has passed through the first lens is incident; a second prism that is joined to the first prism to form a parallel flat plate-like prism light guide member; a flat polarization separation film that is provided at a joint between the first prism and the second prism and that selectively reflects the image light guided in the first prism in accordance with a polarization direction; The first prism is provided with an angle selective film that is disposed on the outer surface onto which the image light reflected by the film is incident and that exhibits different separation characteristics depending on the angle of incidence of the image light; a plano-convex second lens having a flat surface disposed opposite the angle selective film; a transmissive mirror that is disposed on the convex surface of the second lens and partially reflects the image light reflected by the polarization separation film toward the polarization separation film; a quarter-wave plate that is disposed between the angle selective film and the flat surface of the second lens; and a compensation lens that has a shape that is the inverse of the convex surface of the second lens and has a concave surface that is joined to the convex surface via the transmissive mirror, and a flat surface that is parallel to the outer surface of the first prism.

[0006] An optical unit according to one aspect of the present invention is a direct virtual image type optical unit, comprising: a first lens having positive refractive power, on which image light from a display element emitting image light is incident; a first prism on which the image light passing through the first lens is incident; a second prism joined to the first prism to form a parallel flat plate-like prism light guide member; a flat polarization separation film provided at a joint between the first prism and the second prism, which selectively reflects the image light guided in the first prism in accordance with a polarization direction; The optical element comprises an angle selective film disposed on the outer surface on which the reflected image light is incident and exhibiting different separation characteristics depending on the angle of incidence of the image light; a plano-convex second lens having a flat surface disposed opposite the angle selective film; a transmissive mirror disposed on the convex surface of the second lens and partially reflecting the image light reflected by the polarization separation film toward the polarization separation film; a quarter-wave plate disposed between the angle selective film and the flat surface of the second lens; and a compensation lens having a concave surface having a shape that is the inverse of the convex surface of the second lens and joined to the convex surface via the transmissive mirror, and a flat surface that is parallel to the outer surface of the first prism. [Brief description of the drawings]

[0007] [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 shows the reflection and transmission characteristics of an angle selective film. [Figure 4] 4 is a partial enlarged view for explaining a light beam transmitted through or reflected within a first prism. FIG. [Diagram 5] 13 is a table showing examples of angles of view in the upward direction. [Figure 6] 13 is a table showing examples of angles of the viewing angle in the downward direction. [Figure 7] FIG. 2 is a perspective view illustrating the external structure of a first display unit. [Figure 8] 3A to 3C are diagrams for explaining the shapes of a first image-forming element and a first lens, etc. FIG. [Figure 9]4 is a perspective view for explaining an example of the structure and assembly of a first display unit. FIG. [Figure 10] 4 is a cross-sectional view illustrating an example of assembly of the first display unit. FIG. [Figure 11] 10A to 10C are cross-sectional views illustrating an example of assembly of a first display unit of the virtual image display device according to the second embodiment. [Figure 12] FIG. 11 is a side cross-sectional view illustrating a virtual image display device according to a third embodiment. [Figure 13] 13 is a conceptual diagram illustrating the operation of the virtual image display device shown in FIG. 12. [Figure 14] 13 is a conceptual diagram illustrating the operation of the modified example of the virtual image display device shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] [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.

[0009] 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.

[0010] 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 glasses lens 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 glasses lens 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 end sides 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.

[0011] 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 image forming element 11a, a first display unit 20a, and a first circuit member 80a. The first image forming element 11a is also called a display element 11. The first display unit 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 lens 30, a first flat-plate member 40, and a second flat-plate member 50. The first lens 30 functions as a protective glass that protects the display surface 11d of the display element 11. The first flat-plate member 40 guides the image light ML emitted from the display element 11 to the second 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 by partially returning the image light ML from the first plate-shaped member 40 to the first plate-shaped member 40, and also allows external light OL to be incident on the pupil position PP via the first plate-shaped member 40. The first lens 30, the first plate-shaped member 40, and the second plate-shaped member 50 each function as a lens having a positive refractive power.

[0012] Although detailed description will be omitted, the second virtual image display device 100B includes a second image forming element 11b, a second display unit 20b, and a second circuit member 80b. The second image forming element 11b is similar to the first image forming element 11a, the second display unit 20b is similar to the first display unit 20a, and the second circuit member 80b is similar to the first circuit member 80a.

[0013] In the first virtual image display device 100A, the first image forming element 11a is a self-luminous image light generating device. The first image forming element 11a emits the image light ML to the first flat plate-like member 40 through the first lens 30. The first image forming element 11a is housed and supported in the case 71. The first image forming element 11a is, for example, an organic EL (organic electroluminescence) display, and forms a color still image or a moving image on a two-dimensional display surface 11d. The first image forming element 11a is driven by the first circuit member 80a to perform a display operation. The first image forming 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 first image forming element 11a is not limited to a self-luminous image light generating device, and may be composed of an LCD or other light modulation element, and may form an image by illuminating the light modulation element with a light source such as a backlight. As the first image forming element 11a, instead of an LCD, LCOS (Liquid crystal on silicon, LCoS is a registered trademark), a digital micromirror device, or the like can be used. In the first virtual image display device 100A, the 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 first display unit 20a includes a first lens 30, a first flat-plate member 40, a polarization separation film 45, and a second flat-plate member 50. In the first display unit 20a, the first lens 30 has a positive refractive power, and the image light ML from the first image forming element 11a is incident on the first lens 30. The first lens 30 has a flat light entrance surface 30f that is bonded to the first image forming element 11a, 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 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 lens 30 becomes less noticeable. The lens portion 32 is a plano-convex lens having a positive refractive power. The plano-convex lens has one surface that has a planar shape and the other surface that has a convex shape. The first lens 30 is made of, for example, fused silica, and has a relatively low refractive index.

[0015] The first flat-plate member 40 has a first prism 41 in the shape of a parallel flat plate and a second prism 42 in the shape of a parallel flat plate. 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 polarization separation film 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 the second flat-plate member 50 described later corresponds to the first combiner 103a in FIG. 1.

[0016] The first prism 41 has a rectangular 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, and the optical axis passing through the incident optical surface 41a extends in a direction between the +Z direction in the front and the +Y direction in the upward direction. This makes it easier to arrange the first image forming element 11a, which is the display element 11, on the outside side than the inner surface 41b, and the angle at which the image light ML propagates in the first prism 41 (in the first prism 41 or inside 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 lens portion 44 including the incident optical surface 41a. The lens portion 44 is a convex plano lens having a positive refractive 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, and specifically forms an angle of 25° to 32°, as will be described in detail later. The distance between the optical axis AX passing through the pupil position PP and the first 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 lens 30.

[0017] The number of reflections of the image light ML in the first prism 41 is once at the inner surface 41b, once at the outer surface 41c, and once at the polarization separation film 45 described below. By making the number of 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 image forming element 11a because no intermediate image is formed in the first display unit 20a or the imaging optical system IS, but it enters the inner surface 41b and the outer surface 41c in a divergent state, and the divergent state is maintained.

[0018] The second prism 42, like the first prism 41, has a rectangular 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 or abrasion resistance. The second prism 42 is made of a resin material and has a refractive index equal to that of the first prism 41.

[0019] The polarization separation film 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. The space between the polarization separation film 45 and the inclined surface 42d is filled with a bonding adhesive CT. The polarization separation film 45 is formed of a dielectric multilayer film, and when the image light ML contains s-polarized light s, it efficiently reflects the s-polarized image light ML, and when the image light ML contains p-polarized light p, it efficiently transmits the p-polarized image light ML. The polarization separation film 45 may be any film that selectively reflects the image light ML according to the polarization direction, and may be, for example, a wire grid. The polarization separation film 45 may have a flat surface that does not affect the image formation. The polarization separation film 45 may have a slightly convex or concave curved surface that does not affect the image formation. The polarization separation film 45 can have a hard coat on its surface to increase its scratch resistance or abrasion resistance. The space between the polarization separation film 45 and the inclined surface 41d may be filled with a transparent filler instead of the adhesive CT. In this case, the first prism 41 and the second prism 42 may be supported from the outside by a support member or the like to maintain the bonded state. The polarization separation film 45 may be integrally formed on the inclined surface 42d of the second prism 42 instead of on the inclined surface 41d of the first prism 41.

[0020] The inclination angle θ of the polarization splitting film 45 is 90°-β0 or more, assuming that the reflection angle of the image light ML on the optical axis AX in the first prism 41 is β0. Assuming that the polarization splitting film 45 does not obstruct the path of the image light ML, assuming that the maximum reflection angle of the image light ML is βmax, it is desirable that the inclination angle θ of the polarization splitting film 45 is smaller than 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, and is an acute angle. In other words, the optical axis AX of the incident optical surface 41a extends in a direction less than 90° with respect to the normal to the inner surface 41b. Note that, as will be described in detail later, the inclination angle θ of the polarization splitting film 45 corresponds to the PBS angle θ described later, and the range of the PBS angle θ is limited so that the reflected light incident on the angle selection film 60 described later is reflected by the angle selection film 60. Moreover, the reflection angle β0 corresponds to the case where the reflection incident angle γ, which will be described later, relates to the image light ML on the optical axis AX.

[0021] The second flat member 50 has a thin quarter-wave plate 51 and a cover member 52. The quarter-wave plate 51 is a crystal or the like having an optical axis between the X direction and the Y direction, and converts the s-polarized image light ML reflected by the polarization separation film 45 into circularly polarized light c, and converts the circularly polarized image light c reflected by the cover member 52 into p-polarized light p. The cover member 52 has a plano-convex second lens 53, a concave-plano compensation lens 54, a compensation plate 55 provided around the compensation lens 54, and a transmissive mirror 56.

[0022] An angle selection film 60 is provided between the prism light-guiding member 48 and the second flat-plate member 50. That is, the angle selection film 60 is provided between the outer surface 48c of the prism light-guiding member 48 or the outer surfaces 41c, 42c of the first flat-plate member 40 and the inner surface 50c of the second flat-plate member 50. By providing the angle selection film 60 on the outer surface 48c of the prism light-guiding member 48, it is not necessary to provide a clearance between the outer surfaces 41c, 42c of the first flat-plate member 40 and the inner surface 50c of the second flat-plate member 50. This makes it possible to bond the second flat-plate member 50 directly onto the angle selection film 60. Specifically, the angle selection film 60 and the ¼ wavelength plate 51 of the second flat-plate member 50 are bonded with an adhesive. It is preferable that the angle selection film 60 is provided on the outer surface 41c of the first prism 41 in the first flat-plate member 40.

[0023] The angle selective film 60 is an angle-dependent separation film that exhibits different separation characteristics depending on the angle of incidence of light. The angle selective film 60 functions as a flat transmissive reflecting surface that reflects the image light ML reflected by the inner surface 41b of the first prism 41 and transmits the image light ML reflected by the polarization separation film 45.

[0024] Fig. 3 is a diagram showing the reflection and transmission characteristics of the angle selective film 60. In Fig. 3, the horizontal axis is the angle of incidence (unit: °) of light incident on the outer surface 41c of the first prism 41, and the vertical axis is the reflectance (unit: %) relative to the angle of incidence. Symbol LR indicates a red light ray, symbol LG indicates a green light ray, and symbol LB indicates a blue light ray. The angle selective film 60 is a film that transmits the image light ML when the angle of incidence is 20° or less, and reflects the image light ML when the angle of incidence is 40° or more.

[0025] FIG. 4 is a partial enlarged view for explaining light rays transmitted or reflected in the first prism 41 of the prism light-guiding member 48. As shown by the dotted line L1 in FIG. 4, the field angle in the upward direction of the field of view is defined as +, and as shown by the dashed line L2 in FIG. 4, the field angle in the downward direction of the field of view FOV is defined as -. In the first prism 41 of the prism light-guiding member 48, the incident angle (transmission incident angle) of the transmitted light ray M1 incident on the angle selection film 60 is defined as α, and the incident angle (reflection incident angle) of the reflected light ray M2 incident on the angle selection film 60 is defined as γ. In addition, the angle (PBS angle) between the surface of the polarization separation film 45 and the surface of the angle selection film 60 is defined as θ. Here, each angle α, γ, and θ are set assuming that the light ray travels from the pupil position PP. The refractive index of the first prism 41 is 1.75. FIG. 5 is a table showing examples of each angle for the field angle in the upward direction of the field of view FOV. FIG. 6 is a table showing examples of angles of view in the downward direction of the viewing angle FOV.

[0026] The relationship between the viewing angle FOV and the polarization separation film 45 will be described below. The angle (PBS angle θ) of the inclined surface 41d of the first prism 41 on which the polarization separation film 45 is formed needs to be decreased as the viewing angle FOV increases so that the reflected light ray M2 of the angle selection film 60 does not intersect with the surface of the polarization separation film 45. In addition, as shown in Fig. 6, the reflected incident angle γ is limited to a range in which the reflected light ray M2 incident on the angle selection film 60 is reflected by the angle selection film 60, specifically, to 40° or more.

[0027] 5 and 6 can be expressed by the following expressions (1) and (2): The PBS angle θ is adjusted so as to satisfy the following expressions (3) and (4). TIFF2025006918000002.tif16166TIFF2025006918000003.tif11166Here, the lower limit value of the PBS angle θ is expressed by the following formula. TIFF2025006918000004.tif12166 On the other hand, there is a condition for the reflected light ray M2 incident on the angle selection film 60 to be reflected. In the case of this embodiment, the light is reflected when the reflection incident angle γ is 40° or more, so when 40 is substituted for the value γ in the above formula (1), the following condition is satisfied. TIFF2025006918000005.tif12166

[0028] The angle selective film 60 is a dielectric multilayer film formed by laminating multiple dielectrics having different refractive indices. The angle selective film 60 has a film configuration that has almost no absorption and no polarization dependency. Specifically, the angle selective film 60 is formed of a dielectric multilayer film in which, for example, a transparent film with a high refractive index (e.g., TiO2, HfO2) and a transparent film with a low refractive index (e.g., SiO2, MgF2) are alternately stacked.

[0029] In the cover member 52, the second lens 53 is thin but has a positive refractive power, and has a flat surface 53f bonded to the quarter-wave plate 51, and a convex surface 53g facing the compensation lens 54. The convex surface 53g is, for example, a spherical surface, but can be an axially symmetric aspheric surface. The compensation lens 54 is thin but has a positive refractive power, and has a concave surface 54f facing the second 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 compensation plate 55 has the same shape as the convex surface 53g of the second lens 53. The flat surface 54g of the compensation lens 54 and the flat surface 55g of the compensation plate 55 are on the same plane and are continuous. The transparent mirror 56 is a thin film formed on the convex surface 53g of the second lens 53, and has the same shape as the convex surface 53g. The combination of the second lens 53 and the transmissive mirror 56 is called a light-collecting reflector CR.

[0030] The second lens 53 is formed by filling an adhesive such as a photocurable resin into a filling space formed between an area of ​​the cover member 52 corresponding to the compensation lens 54 and the quarter-wave plate 51. The photocurable resin is photocured after filling. Examples of the photocurable resin include an acrylic resin adhesive that is cured by ultraviolet light or visible light, specifically LOCTITE (registered trademark) AA3301 (manufactured by Henkel). Note that a thermosetting resin can also be used as the adhesive.

[0031] Regarding the dimensions of second lens 53, the diameter is 20 mm to 25 mm, specifically, about 22 mm. The thickness of the center of second lens 53 is 3 mm or less, and preferably 1 mm to 1.7 mm. The thickness of the edge or outer periphery of second lens 53 is 0.2 mm to 0.5 mm.

[0032] When the thickness of the second lens 53 is about 1 mm, it is difficult to manufacture the second lens 53 by polishing or injection molding. Therefore, in this embodiment, the concave curved surface of the cover member 52 corresponding to the compensation lens 54 facing the second lens 53 is used as a molding die, and the second lens 53 is molded when the first display unit 20a is assembled. Specifically, the second lens 53 is formed by butting the cover member 52 excluding the second lens 53, that is, the compensation lens 54 and the 1 / 4 wavelength plate 51 together, and filling the filling space with adhesive through a flow path (not shown). The second lens 53 is molded by hardening the adhesive, and the 1 / 4 wavelength plate 51 and the cover member 52 are bonded together. This allows the second lens 53 to be easily formed even if it is thin. An adhesive having a refractive index equivalent to that of the compensation lens 54 is used.

[0033] The compensation lens 54 and the compensation plate 55 are formed from a resin material. The second lens 53, the compensation lens 54, and the compensation plate 55 have the same refractive index. The refractive index of the second lens 53, etc. is lower than the refractive index of the first prism 41. The compensation lens 54 and the compensation plate 55 are optical elements 58 integrally formed from the same resin material.

[0034] The combination of the second lens 53, the compensation lens 54, and the compensation plate 55 functions as a parallel plate as a whole. That is, the external light OL incident on the position of the compensation lens 54 or the compensation plate 55 passes through them without being affected by the lens action of the compensation lens 54 or the like or the step existing on the outer edge of the compensation lens 54. The flat surfaces 54g, 55g of the compensation lens 54 and the compensation plate 55 may be coated with an anti-reflection film or a hard coat. The external light OL that has passed through the compensation plate 55 passes through the top, bottom, left, and right of the compensation lens 54, and is incident from the peripheral area outside the incident area of ​​the image light ML corresponding to the compensation lens 54, that is, from the compensation plate 55. This ensures a wide see-through field of view with respect to the outside world. The field of view of the external light OL is set, for example, to about 40° upward and about 40° downward.

[0035] As described above, the diameter of the second 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 surfaces 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°.

[0036] The transmissive mirror 56 is a half mirror that partially reflects the image light ML that has passed through the second lens 53 and partially transmits the outside light OL. The transmissive mirror 56 reflects the image light ML that has been reflected by the polarization separation film 45 of the first flat plate member 40 and passed through the angle selection film 60, the ¼ wavelength plate 51, and the second lens 53 toward the pupil position PP. The transmissive mirror 56 is a concave mirror that covers the pupil position PP where the eye EY or pupil is located, has a concave shape toward the pupil position PP, and has 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.

[0037] The transparent mirror 56 transmits a part of the outside light OL, so that a see-through view of the outside world is possible, and a virtual image can be superimposed on an outside image. 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. The reflectance of the transparent mirror 56 for the image light ML and the outside light OL is set to 10% or more and 50% or less in the assumed range of incidence angles of the image light ML, from the viewpoint of ensuring the brightness of the image light ML and facilitating the observation of the outside image by the see-through. The transparent mirror 56 is formed, for example, of a dielectric multilayer film made of a plurality of dielectric layers whose film thicknesses are adjusted. The transparent mirror 56 may be a single layer film or a multilayer film of a metal such as Al or Ag whose film thickness is adjusted. The transparent mirror 56 is formed, for example, by lamination using vapor deposition.

[0038] In the first virtual image display device 100A, the first lens 30, the lens unit 44, the second lens 53, and the transparent mirror 56 each have a positive refractive power and tend to converge divergent light. The first lens 30, the lens unit 44, the second lens 53, and the transparent mirror 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 allows the real image formed on the display surface 11d of the first image forming element 11a to be formed as a virtual image projected, for example, at infinity, or the real image formed on the display surface 11d to be formed as a virtual image projected several meters ahead. At this time, by adjusting the refractive power of the first lens 30, the lens unit 44, the second lens 53, and the transparent mirror 56, the focal length of the imaging optical system IS can be shortened to achieve a desired magnification ratio.

[0039] With reference to FIG. 7, the vertical size ay of the first flat plate member 40 or the second flat plate member 50 is, for example, 34 mm, and the horizontal size ax is, for example, 40 mm. The thickness az of the first flat plate member 40 in the front-rear direction is, for example, about 7 mm, and the combined thickness of the first flat plate member 40 and the second flat plate member 50 is suppressed to about 7.5 mm. In the first flat plate 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) that faces and covers the upper flat surface 40u may be disposed on the upper flat surface 40u, or a light shielding body may be applied to the upper flat surface 40u. The horizontal flat surface 40v and the lower flat surface 40w may also be provided with a light shielding body or the like that covers them. The periphery of the second flat plate member 50 may also be provided with a light shielding body or the like that covers it.

[0040] The shapes of the first image forming element 11a and the first lens 30 will be described with reference to Fig. 8. In Fig. 8, area AR1 shows the first lens 30 etc. as viewed obliquely upward from the front +Z side, area AR2 shows the first lens 30 etc. as viewed obliquely forward from the lower -Y side, and area AR3 shows the first lens 30 etc. as viewed from the side +X side. The thickness or height H of the first lens 30 is, for example, about 2 mm, the width W of the first lens 30 is, for example, about 14 mm, and the depth D of the first lens 30 is, for example, about 7 mm.

[0041] The radius of curvature of the convex light exit surface 30g of the first lens 30 is, for example, 20 mm. Additionally, the radius of curvature of the incident optical surface 41a of the first prism 41 shown in FIG. 2 is, for example, 14 mm, and the radius of curvature of the transmissive mirror 56 is, for example, 47 mm.

[0042] Returning to FIG. 2, the optical path will be described. The image light ML from the first image forming element 11a enters the first prism 41 via the first lens 30. At this time, the degree of divergence of the image light ML is suppressed by the positive refractive power of the first lens 30 and the lens unit 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 the s component of the image light ML is reflected by the polarization separation film 45. The s-polarized s image light ML reflected by the polarization separation film 45 passes through the outer surface 41c of the first prism 41 and the angle selection film 60, and passes through the ¼ wavelength plate 51 of the second flat plate-like member 50 to become circularly polarized light c, and enters the transmissive mirror 56. The circularly polarized image light ML incident on the transmissive mirror 56 is partially reflected by the transmissive mirror 56 through the second lens 53, and passes through the quarter-wave plate 51 again in a collimated state through the second lens 53. As a result, the image light ML passing through the quarter-wave plate 51 becomes p-polarized p, passes through the angle selection film 60, enters the first prism 41 from the outer surface 41c, transmits through the polarization separation film 45, and is emitted to the outside of the second prism 42 through the inner surface 42b. The image light ML emitted to the outside of the second prism 42 enters the pupil position PP where the eye EY or pupil of the wearer US is located. Not only the image light ML reflected by the transmissive mirror 56, but also the outside light OL transmitted through the transmissive mirror 56 and the outside light OL transmitted through the compensation plate 55 enter the pupil position PP. In other words, 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.

[0043] An example of the structure and assembly of the first display unit 20a constituting the first virtual image display device 100A will be described with reference to FIG. 9 and FIG. 10. In FIG. 9, areas BR1 to BR4 are perspective views for explaining the assembly process of the first display unit 20a. In FIG. 10, areas CR1 to CR5 are cross-sectional views for explaining the assembly process of the first display unit 20a. First, as shown in area BR1 of FIG. 9, the first prism 41 and the second prism 42 are prepared. The first prism 41 and the second prism 42 are formed, for example, by injection molding of a resin. The first prism 41 has an incident optical surface 41a, an inner surface 41b, an outer surface 41c, and the like. The second prism 42 has an inner surface 42b, an outer surface 42c, and the like. On one side, a polarization separation film 45 is formed on the inclined surface 41d of the first prism 41 by vacuum deposition or other techniques. As shown in region BR2 of FIG. 9 and region CR1 of FIG. 10, the first prism 41 and the second prism 42 are joined at the inclined surfaces 41d and 42d to obtain the first flat-plate member 40. Next, as shown in region CR2 of FIG. 10, an angle selection film 60 is formed on the outer surfaces 41c and 42c of the first flat-plate member 40 by vacuum deposition or other techniques. Next, as shown in region BR3 of FIG. 9 and region CR3 of FIG. 10, a quarter-wave plate 51 is attached to face the outer surfaces 41c and 42c of the first flat-plate member 40. As shown in region BR4 of FIG. 9 and region CR4 of FIG. 10, the compensation plate 55 and the quarter-wave plate 51 of the optical element 58 are butted against each other. As a result, a filling space CV is formed between the compensation lens 54 and the quarter-wave plate 51 as a molding die for the second lens 53. A transmissive mirror 56 is formed on the concave surface of the compensation lens 54 facing the quarter-wave plate 51. Next, as shown in region CR5 of FIG. 10, adhesive MA, which is the material of second lens 53, is injected from a flow path (not shown) formed by a groove provided in optical element 58, and the adhesive MA is filled into filling space CV corresponding to second lens 53. After that, the filled adhesive MA is cured by irradiating it with ultraviolet light UV or the like. As a result, second lens 53 is formed in a bonded state between quarter-wave plate 51 and compensation lens 54. This completes the assembly of first display unit 20a. When compensating plate 55 and quarter-wave plate 51 are butted together, they may be bonded together with an adhesive.

[0044] The virtual image display devices 100A, 100B or the optical unit 100 according to the first embodiment described above is a direct virtual image type virtual image display device, and includes a display element 11 that emits image light ML, a first lens 30 having a positive refractive power and on which the image light ML from the display element 11 is incident, a first prism 41 on which the image light ML that has passed through the first lens 30 is incident, a second prism 42 that is joined to the first prism 41 to form a parallel plate-like prism light-guiding member 48, a flat polarization separation film 45 that is provided at the joint between the first prism and the second prism 42 and that selectively reflects the image light ML guided in the first prism 41 in accordance with the polarization direction, and a polarization separation film 45 that selectively reflects the image light ML guided in the first prism 41 in accordance with the polarization direction in the prism light-guiding member 48. the second lens 53 having a flat surface 53f arranged opposite the angle selective film 60; a transmissive mirror 56 arranged on the convex surface 53g of the second lens 53 and partially reflecting the image light ML reflected by the polarization separation film 45 toward the polarization separation film 45; a quarter-wave plate 51 arranged between the angle selective film 60 and the flat surface 53f of the second lens 53; and a compensation lens 54 having a concave surface 54f having a shape that is an inverted shape of the convex surface 53g of the second lens 53 and joined to the convex surface 53g via the transmissive mirror 56, and a flat surface 55g parallel to the outer surface 41c of the first prism 41.

[0045] In the above-mentioned virtual image display devices 100A, 100B or optical unit 100, a virtual image is formed directly without forming an intermediate image, so that the refractive power is ensured by the first lens 30, the second lens 53 and the transmissive mirror 56, and the magnification is 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.

[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] As shown in FIG. 11, the second lens 53 is formed of a liquid LA filled in a filling space CV between the compensation lens 54 and the quarter-wave plate 51. The liquid LA is a refractive index adjusting member having a refractive index equivalent to that of the compensation lens 54. By using the liquid LA having a refractive index equivalent to that of the compensation lens 54 as the material of the second lens 53, it is effective when a refractive index equivalent to that of the compensation lens 54 cannot be obtained by adhesive. Examples of the refractive index adjusting member include Cargill standard refractive index liquid (manufactured by Moritex Corporation), specifically, Immersion Oil Type FF (refractive index: 1.4790), Optical Gel 608 (refractive index: 1.46), Immersion Liquid 5040 (refractive index: 1.4590 to 1.5700), etc. Also, the refractive index adjusting member may be a refractive index matching film (manufactured by Tomoegawa Paper Co., Ltd.), specifically, Fit Well (registered trademark, refractive index: 1.46).

[0048] In the cover member 52, a concave curved surface corresponding to the compensation lens 54 facing the second lens 53 is used as a mold, and the 1 / 4 wavelength plate 51 and the compensation plate 55 are bonded with an adhesive. A flow path is formed in the compensation lens 54 for injecting the material of the second lens 53. After the 1 / 4 wavelength plate 51 and the compensation plate 55 are bonded, a refractive index adjusting member which is a liquid LA is filled into a filling space formed between the 1 / 4 wavelength plate 51 and the compensation lens 54 via the flow path, and the periphery of the liquid LA is sealed with an adhesive. This makes it possible to easily form the second lens 53 even if it is thin. The refractive index adjusting member has a refractive index equivalent to that of the compensation lens 54.

[0049] An example of the structure and assembly of the first display unit 20a constituting the first virtual image display device 100A will be described below. In FIG. 11, regions DR1 to DR5 are cross-sectional views for explaining the assembly process of the first display unit 20a. As shown in region DR1 of FIG. 11, the first prism 41 and the second prism 42 are joined at the inclined surfaces 41d and 42d to obtain the first flat-plate member 40. Next, as shown in region DR2 of FIG. 11, an angle selection film 60 is formed on the outer surfaces 41c and 42c of the first flat-plate member 40 by vacuum deposition or other techniques. Next, as shown in region DR3 of FIG. 11, a quarter-wave plate 51 is attached to face the outer surfaces 41c and 42c of the first flat-plate member 40. As shown in region DR4 of FIG. 11, the compensation plate 55 and the quarter-wave plate 51 of the optical element 58 are butted against each other and joined using an adhesive AM. Specifically, the adhesive AM is a photo-curable resin such as an ultraviolet-curable resin, and the compensation plate 55 and the quarter-wave plate 51 are bonded by irradiating the adhesive AM with ultraviolet light UV or the like. As a result, a filling space CV is formed between the compensation lens 54 and the quarter-wave plate 51 as a shape-retaining frame for the second lens 53. A transmissive mirror 56 is formed on the concave surface of the compensation lens 54 facing the quarter-wave plate 51. Next, as shown in the region DR5 of FIG. 11, the liquid LA, which is the material of the second lens 53, is injected from a flow path (not shown) formed by a groove provided in the optical element 58, and the liquid LA is filled into the filling space CV corresponding to the second lens 53. After that, the flow path is sealed with an adhesive. As a result, the second lens 53 is formed between the quarter-wave plate 51 and the compensation lens 54. With the above, the assembly of the first display unit 20a is completed.

[0050] Third Embodiment Hereinafter, the virtual image display device of the third embodiment will be described. Note that 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 the parts common to the virtual image display device of the first embodiment will be omitted.

[0051] In the case of the first virtual image display device 100A shown in FIG. 12, for example, an s-polarized light transmitting polarizing plate 12 is disposed between the first lens 30 and the first image forming element 11a in the first display unit 20a. However, the s-polarized light transmitting polarizing plate 12 is not essential in terms of function. Also, in the first display unit 20a, a third flat plate member 150 is added to the outside world side of the second flat plate member 50. The third flat plate member 150 is an image light blocking unit LP, and includes an outer ¼ wavelength plate 151 provided on the outside world side of the light collecting reflection unit CR, and a polarizing plate 59 provided on the outside world side of the outer ¼ wavelength plate 151 and selectively absorbing the image light ML transmitted through the ¼ wavelength plate 151 according to the polarization direction. That is, in the first display unit 20a, the inner ¼ wavelength plate 51 and the outer ¼ wavelength plate 151 are disposed between the inner polarization separation film 45 and the outer polarizing plate 59.

[0052] 13, the image light ML from the first image forming element 11a (see FIG. 12) contains only s-polarized light, and the s-polarized image light ML incident on the polarization separation film 45 is reflected by the polarization separation film 45 without loss, passes through the inner quarter-wave plate 51, becomes circularly polarized light, and enters the transmissive mirror 56. The circularly polarized image light ML incident on the transmissive mirror 56 is partially reflected by the transmissive mirror 56, and passes through the inner quarter-wave plate 51 again in the reverse direction. The image light ML that passes through the inner quarter-wave plate 51 in the reverse direction becomes p-polarized light, passes through the polarization separation film 45, and enters the pupil position PP (see FIG. 12). On the other hand, the circularly polarized image light ML that passes through the transmissive mirror 56 passes through the outer quarter-wave plate 151, becomes p-polarized light, enters the polarizing plate 59, and is mostly blocked by the polarizing plate 59. That is, the image light ML is blocked by the third flat plate-shaped member 150 and does not leak out to the outside. That is, the image light ML can be prevented from being observed from the outside, so privacy can be ensured.

[0053] On the other hand, the external light OL incident on the polarizing plate 59 becomes only s-polarized light by passing through the polarizing plate 59, becomes circularly polarized light by passing through the outer quarter-wave plate 151, and is partially transmitted through the transmissive mirror 56. The circularly polarized external light OL that has partially transmitted through the transmissive mirror 56 becomes p-polarized light by passing through the inner quarter-wave plate 51, transmits through the polarization separation film 45, and is incident on the pupil position PP (see FIG. 12).

[0054] Fig. 14 is a diagram illustrating a modified example of the first virtual image display device 100A shown in Fig. 12 and Fig. 13. In this case, the polarizing plate 59 constituting the third flat plate member 150 shown in Fig. 12 transmits s-polarized light and reflects p-polarized light.

[0055] The difference from FIG. 13 is that the circularly polarized image light ML partially transmitted through the transmissive mirror 56 becomes p-polarized light by passing through the outer quarter-wave plate 151, and most of it is reflected by the polarizing plate 59 and does not leak out of the polarizing plate 59. The p-polarized image light ML reflected by the polarizing plate 59 passes through the outer quarter-wave plate 151 again in the reverse direction. The p-polarized image light ML passing through the outer quarter-wave plate 51 becomes circularly polarized light and is partially reflected by the transmissive mirror 56, but does not pass through the polarizing plate 59. The circularly polarized image light ML partially transmitted through the transmissive mirror 56 passes through the inner quarter-wave plate 51 again in the reverse direction. The image light ML passing through the inner quarter-wave plate 51 becomes s-polarized light and is reflected by the polarization separation film 45, and is returned toward the first image forming element 11a.

[0056] On the other hand, the external light OL incident on the polarizing plate 59 becomes only s-polarized light by passing through the polarizing plate 59, becomes circularly polarized light by passing through the outer quarter-wave plate 151, and is partially transmitted through the transmissive mirror 56. The circularly polarized external light OL that is partially transmitted through the transmissive mirror 56 becomes p-polarized light by passing through the inner quarter-wave plate 51, transmits through the polarization separation film 45, and is incident on the pupil position PP (see FIG. 12). Note that the p-polarized light of the external light OL is reflected by the polarizing plate 59, but this does not cause any particular problem, and rather serves to prevent the surface of the first display unit 20a from becoming too dark.

[0057] [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.

[0058] 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.

[0059] In the method of assembling the first display unit 20a, the second lens 53 is formed during the assembly process. However, the second lens 53 may be separately manufactured by injection molding or the like and bonded.

[0060] The compensation plate 55 may be omitted from the cover member 52. In this case, the quarter-wave plate 51 is disposed only in the range of the second lens 53, and the second lens 53 is covered by the compensation lens .

[0061] The incident optical surface 41a may be omitted in the first prism 41 of the first flat plate member 40. In this case, the optical system does not include the lens portion 44.

[0062] The first lens 30 is not limited to being bonded to the first image-forming element 11a, but may be disposed separately from the first image-forming element 11a.

[0063] The first prism 41 and the second prism 42 may be made of glass instead of a resin material.

[0064] The first image forming element 11a may be a scanning type display device having a laser light source and a scanner mirror.

[0065] A virtual image display device in a specific embodiment is a direct virtual image type virtual image display device, comprising: a display element that emits image light; a first lens having positive refractive power and into which the image light from the display element is incident; a first prism into which the image light that has passed through the first lens is incident; a second prism that is joined to the first prism to form a parallel flat plate-like prism light guide member; a flat polarization separation film that is provided at the joint between the first prism and the second prism and that selectively reflects the image light guided in the first prism in accordance with the polarization direction; The optical element comprises an angle selective film that is disposed on the outer surface onto which the image light reflected by the film is incident and that exhibits different separation characteristics depending on the angle of incidence of the image light; a plano-convex second lens having a flat surface disposed opposite the angle selective film; a transmissive mirror that is disposed on the convex surface of the second lens and partially reflects the image light reflected by the polarization separation film toward the polarization separation film; a quarter-wave plate that is disposed between the angle selective film and the flat surface of the second lens; and a compensation lens that has a shape that is the inverse of the convex surface of the second lens and has a concave surface that is joined to the convex surface via the transmissive mirror, and a flat surface that is parallel to the outer surface of the first prism.

[0066] In the above-mentioned virtual image display device, a virtual image is formed directly without forming an intermediate image, so that refractive power is ensured by the first lens, the second lens, and the transmissive mirror, thereby ensuring the magnification while suppressing an increase in the optical path length, and avoiding an increase in the size of the optical system.

[0067] In a specific embodiment of the virtual image display device, the first lens, the prism light guide member, the polarization separation film, the angle selection film, the second lens, the transmissive mirror, and the quarter-wave plate constitute a simple microscope-type imaging optical system that forms an erect image, and the first prism internally reflects the image light twice while diverging it. In this case, it is easy to shorten the distance from the display element to the transmissive mirror, and the prism light guide member can be made compact, and it is also easy to make the display element and the first lens compact.

[0068] In a specific embodiment of a virtual image display device, the angle selection film is composed of a dielectric multilayer film, and transmits image light when the angle of incidence on the angle selection film is 20° or less, and reflects the image light when the angle of incidence on the angle selection film is 40° or more.

[0069] In a specific embodiment, the virtual image display device further includes a compensation plate provided around the compensation lens and extending parallel to the prism light guiding member. In this case, external light incident around the compensation lens can be observed in the same manner as external light incident inside the compensation lens.

[0070] In a specific embodiment of the virtual image display device, the angle selective film and the quarter wave plate are bonded together.

[0071] In a specific embodiment of the virtual image display device, the first lens has a flat light entrance surface that is bonded to the display element and a convex light exit surface. In this case, the first lens can function as a protective glass, and by ensuring that the thickness of the first lens is greater than or equal to a predetermined value, foreign matter attached to the surface of the first lens becomes less noticeable.

[0072] In a specific embodiment of the virtual image display device, the first prism has an entrance optical surface with positive refractive power, and the entrance optical surface has an optical axis extending in a direction less than 90° with respect to the normal line of the inner surface. In this case, the display element is easily disposed closer to the outside world than the inner surface, and it is possible to avoid a situation in which the display element is disposed close to the face and interference is easily generated, and the degree of freedom in terms of the arrangement and size of the projection optical member is increased.

[0073] In a specific embodiment of the virtual image display device, the polarization separation film reflects s-polarized image light and transmits image light that has been reflected by a transmissive mirror and returned through a quarter-wave plate and become p-polarized.

[0074] In a specific embodiment of the virtual image display device, the second lens is formed of an adhesive that bonds the compensation lens and the quarter-wave plate. In this case, even if the second lens is thin, the second lens can be easily formed.

[0075] In a specific embodiment of the virtual image display device, the second lens is formed of a liquid filled in a filling space between the compensation lens and the quarter-wave plate. In this case, the second lens can be easily formed even if the second lens is thin. By using a liquid having a refractive index equivalent to that of the compensation lens as the material of the second lens, it is effective when a refractive index equivalent to that of the compensation lens cannot be obtained with an adhesive. In addition, by using a liquid for the second lens, there is no need to consider the hardening shrinkage of the adhesive.

[0076] In a virtual image display device according to a specific embodiment, the liquid is a liquid refractive index adjusting member filled between the compensation lens and the quarter-wave plate and sealed around the periphery with an adhesive.

[0077] The optical unit in a specific embodiment is a direct virtual image type optical unit, and includes a first lens having a positive refractive power, on which image light from a display element that emits image light is incident, a first prism on which the image light that has passed through the first lens is incident, a second prism that is joined to the first prism to form a parallel flat plate-like prism light guide member, a flat polarization separation film that is provided at the joint between the first prism and the second prism and that selectively reflects the image light guided in the first prism according to the polarization direction, and a polarization separation film that selectively reflects the image light guided in the first prism according to the polarization direction in the prism light guide member. the first prism includes an angle selection film disposed on the outer surface onto which the projected image light is incident and which exhibits different separation characteristics depending on the angle of incidence of the image light; a plano-convex second lens having a flat surface disposed opposite the angle selection film; a transmissive mirror disposed on the convex surface of the second lens and which partially reflects the image light reflected by the polarization separation film toward the polarization separation film; a quarter-wave plate disposed between the angle selection film and the flat surface of the second lens; and a compensation lens having a concave surface having a shape that is the inverse of the convex surface of the second lens and which is joined to the convex surface via the transmissive mirror, and a flat surface that is parallel to the outer surface of the first prism. [Explanation of symbols]

[0078] 11...display element, 30...first lens, 30f...light incidence surface, 30g...light emission surface, 31...parallel plate, 32...lens portion, 40...first plate-shaped member, 41a...incident optical surface, 41b, 42b...inner surface, 41c, 42c...outer surface, 41d, 42d...inclined surface, 44...lens portion, 45...polarized light separation film, 48...prism light guide member, 48c...outer surface, 50...second plate-shaped member, 50c...inner surface, 51...quarter-wave plate, 52...cover member, 53f...flat surface, 53g...convex surface, 54...compensation lens, 54f...concave surface, 54g, 55f, 55g...flat surface, 55...compensation plate, 56...transmissive mirror, 58...optical element, 59... Polarizing plate, 60... angle selection film, 71... case, 90... user terminal, 100... optical unit, 100A... first virtual image display device, 100B... second virtual image display device, 100C... support device, 102a, 102b... display drive unit, 103a, 103b... combiner, AM... adhesive, AX... optical axis, CR... light collecting and reflecting unit, CT... adhesive, CV... filling space, DIS... direct virtual image optical system, EP... exit pupil, EY... eye, FOV... viewing angle, IS... imaging optical system, LA... liquid, LP... image light blocking unit, M1... transmitted light, M2... reflected light, MA... adhesive, ML... image light, OL... outside light, PP... pupil position, US... wearer

Claims

1. A direct virtual image type virtual image display device, A display element that emits image light; a first lens having a positive refractive power and on which the image light from the display element is incident; a first prism into which the image light having passed through the first lens is incident; a second prism bonded to the first prism to form a parallel plate-shaped prism light guide member; a flat polarization separation film provided at a joint between the first prism and the second prism, the flat polarization separation film selectively reflecting the image light guided through the first prism in accordance with a polarization direction; an angle selection film that is disposed on an outer surface of the prism light guide member on which the image light guided in the first prism and reflected by the polarization separation film is incident and that exhibits different separation characteristics according to an incident angle of the image light; a second lens that is a plano-convex lens having a flat surface that is disposed opposite the angle selection film; and a transmissive mirror that is disposed on the convex surface of the second lens and that partially reflects the image light reflected by the polarization separation film toward the polarization separation film. a quarter-wave plate disposed between the angle-selective film and the plane of the second lens; a compensation lens having a concave surface having a shape obtained by inverting the convex surface of the second lens and bonded to the convex surface via the transmissive mirror, and a flat surface parallel to the outer surface of the first prism; A virtual image display device comprising:

2. the first lens, the prism light guiding member, the polarization separation film, the angle selection film, the second lens, the transmissive mirror, and the quarter-wave plate constitute a simple microscope-type imaging optical system that forms an erect image, The virtual image display device according to claim 1 , wherein the first prism internally reflects the image light twice while diverging the image light.

3. 2. The virtual image display device according to claim 1, wherein the angle selection film is composed of a dielectric multilayer film, and transmits the image light when the angle of incidence on the angle selection film is 20° or less, and reflects the image light when the angle of incidence on the angle selection film is 40° or more.

4. The virtual image display device according to claim 1 , further comprising a compensation plate provided around the compensation lens and extending parallel to the prism light guide member.

5. The virtual image display device according to claim 1 , wherein the angle selection film and the quarter-wave plate are bonded together.

6. The virtual image display device according to claim 1 , wherein the first lens has a flat light entrance surface bonded to the display element and a convex light exit surface.

7. the first prism has an entrance optical surface having a positive refractive power; The virtual image display device according to claim 1 , wherein the entrance optical surface has an optical axis extending in a direction that is less than 90° with respect to a normal to the inner surface.

8. 2. The virtual image display device according to claim 1, wherein the polarization separation film reflects the image light that is s-polarized and transmits the image light that has been reflected by the transmissive mirror and passed back through the quarter-wave plate and become p-polarized.

9. The virtual image display device according to claim 1 , wherein the second lens is formed of an adhesive that bonds the compensation lens and the quarter-wave plate.

10. The virtual image display device according to claim 1 , wherein the second lens is formed by a liquid filling a filling space between the compensation lens and the quarter-wave plate.

11. 11. The virtual image display device according to claim 10, wherein the liquid is a liquid refractive index adjusting member filled between the compensation lens and the quarter wave plate and sealed around the periphery with an adhesive.

12. A direct virtual image type optical unit, a first lens having a positive refractive power and on which image light from a display element that emits image light is incident; a first prism into which the image light having passed through the first lens is incident; a second prism bonded to the first prism to form a parallel plate-shaped prism light guide member; a flat polarization separation film provided at a joint between the first prism and the second prism, the flat polarization separation film selectively reflecting the image light guided through the first prism in accordance with a polarization direction; an angle selection film that is disposed on an outer surface of the prism light guide member on which the image light guided in the first prism and reflected by the polarization separation film is incident and that exhibits different separation characteristics according to an incident angle of the image light; a second lens that is a plano-convex lens having a flat surface that is disposed opposite the angle selection film; and a transmissive mirror that is disposed on the convex surface of the second lens and that partially reflects the image light reflected by the polarization separation film toward the polarization separation film. a quarter-wave plate disposed between the angle-selective film and the plane of the second lens; a compensation lens having a concave surface having a shape obtained by inverting the convex surface of the second lens and bonded to the convex surface via the transmissive mirror, and a flat surface parallel to the outer surface of the first prism; An optical unit comprising:

Images