Virtual image display device and optical unit

Abstract

A virtual image display device and an optical unit are provided to prevent an overall optical system from becoming larger. The virtual image display device is a direct virtual image type virtual image display device, and is provided with: a display element; a first lens having positive refractive power and on which image light from the display element is incident; a first prism on which the image light that has passed through the first lens is incident; a second prism joined to the first prism; a planar polarization separation film which is provided at the junction of the first prism and the second prism and which selectively reflects the image light guided by the first prism in accordance with the polarization direction; an angle selection film disposed on an outer surface of the prism light guide member on which the image light guided by the first prism and reflected by the polarization separation film is incident; a second lens disposed so as to face the angle selection film; a transmissive mirror disposed on the convex surface of the second lens and partially reflecting the image light; a 1 / 4 wavelength plate disposed between the angle selection film and the plane of the second lens; and a compensation lens having a shape that inverts the convex surface of the second lens.

Description

Technical Field

[0001] The present invention relates to a see-through virtual image display device and an optical unit capable of observing a virtual image. Background Art

[0002] The following head-mounted display is publicly known: the head-mounted display has a display device, a projection optical component, a prism component and a focusing reflection surface, wherein image light from the projection optical component is incident on the first prism of the prism component and is totally reflected on the outer side surface, after being partially reflected by the semi-transmitting reflection surface formed at the boundary between the first prism and the second prism of the prism component, it passes through the outer side surface of the prism component and is reflected by the focusing reflection surface, returns to the prism component and passes through the semi-transmitting reflection surface, and further passes through the inner side surface opposite to the pupil (see patent document 1).

[0003] Patent Document 1: Japanese Patent Application Publication No. 2020-08749

[0004] In the head mounted display described above, an intermediate image is formed in the first prism, so the optical path length becomes longer and the overall size of the optical system becomes larger. In addition, since the projection optical component is arranged in a direction that is more inclined toward the face than the upper side of the prism component, the projection optical component is arranged near the face and is prone to interference, which places restrictions on the arrangement and size of the projection optical component. Summary of the invention

[0005] A virtual image display device according to one aspect of the present invention is a direct virtual image type virtual image display device, which comprises: a display element that emits image light; a first lens having a positive refractive power, the image light from the display element being incident on the first lens; a first prism, the image light passing through the first lens being incident on the first prism; a second prism that is joined to the first prism to form a parallel flat plate-shaped prism light guide component; a planar polarization separation film that is disposed at a junction between the first prism and the second prism and selectively reflects the image light guided in the first prism according to a polarization direction; and an angle selection film that is disposed in the prism light guide component and reflects the image light guided in the first prism and reflected by the second prism. The outer side surface on which the image light reflected by the polarization separation film is incident shows different separation characteristics according to the incident angle of the image light; a plano-convex second lens having a plane, the plane being arranged opposite to the angle selection film; a transmissive reflector, which is arranged 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 1 / 4 wavelength plate, which is arranged between the angle selection film and the plane of the second lens; and a compensation lens, which has a concave surface and a plane parallel to the outer side surface of the prism light-guiding component, the concave surface having a shape obtained by inverting the convex surface of the second lens and is joined to the convex surface via the transmissive reflector.

[0006] The optical unit of one aspect of the present invention is a direct virtual image type optical unit, which comprises: a first lens having a positive refractive power, onto which image light from a display element emitting image light is incident; a first prism, onto which the image light passing through the first lens is incident; a second prism, which is joined to the first prism to form a parallel flat plate-shaped prism light guide component; a planar polarization separation film, which is disposed at a junction between the first prism and the second prism, and selectively reflects the image light guided in the first prism according to a polarization direction; and an angle selection film, which is disposed in the prism light guide component, and reflects the image light guided in the first prism and reflected by the polarization separation film. The outer side surface on which the image light is incident shows different separation characteristics according to the incident angle of the image light; a plano-convex second lens having a plane, the plane being arranged opposite to the angle selection film; a transmissive reflector, which is arranged on the convex surface of the second lens and reflects part of the image light reflected by the polarization separation film toward the polarization separation film; a 1 / 4 wavelength plate, which is arranged between the angle selection film and the plane of the second lens; and a compensation lens, which has a concave surface and a plane parallel to the outer side surface of the prism light-guiding component, the concave surface having a shape obtained by inverting the convex surface of the second lens and is joined to the convex surface via the transmissive reflector. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 This is an external view illustrating a usage state of the virtual image display device according to the first embodiment.

[0008] Figure 2 It is a side cross-sectional view illustrating the internal structure of a single display device.

[0009] Figure 3 It is a graph showing the reflection and transmission characteristics of the angle selective film.

[0010] Figure 4 It is a partial enlarged view illustrating the light transmitted or reflected in the first prism.

[0011] Figure 5 This is a table showing examples of various angles of viewing angle in the upward direction with respect to the viewing angle.

[0012] Figure 6 This is a table showing examples of various angles of viewing angle in the downward direction with respect to the viewing angle.

[0013] Figure 7 It is a perspective view for explaining the appearance structure of the first display unit.

[0014] Figure 8 This is a diagram for explaining the shapes of the first image forming element and the first lens, etc.

[0015] Fig. 9 This is a perspective view for explaining an example of the structure and assembly of the first display unit.

[0016] Fig.10 This is a cross-sectional view for explaining an example of assembling the first display unit.

[0017] Fig.11 This is a cross-sectional view for explaining an example of assembling the first display unit of the virtual image display device according to the second embodiment.

[0018] Fig.12 It is a side cross-sectional view for explaining the virtual image display device according to the third embodiment.

[0019] Fig.13 Yes Description Fig.12 A conceptual diagram of the operation of the virtual image display device shown.

[0020] Fig.14 Yes Description Fig.12 A conceptual diagram of the operation of a modified example of the virtual image display device shown.

[0021] Description of symbols

[0022] 11: display element; 30: first lens; 30f: light incident surface; 30g: light exit surface; 31: parallel plate; 32: lens portion; 40: first flat plate-shaped component; 41a: incident optical surface; 41b, 42b: inner side surface; 41c, 42c: outer side surface; 41d, 42d: inclined surface; 44: lens portion; 45: polarization separation film; 48: prism light guide component; 48c: outer side surface; 50: second flat plate-shaped component; 50c: inner side surface; 51: 1 / 4 wavelength plate; 52: cover component; 53f: plane; 53g: convex surface; 54: compensation lens; 54f: concave surface; 54g, 55f, 55g: plane; 55: compensation plate; 56: transmissive reflector; 58: optical element; 59: polarizing plate ; 60: angle selection film; 71: shell; 90: user terminal; 100: optical unit; 100A: first virtual image display device; 100B: second virtual image display device; 100C: supporting device; 102a, 102b: display driving unit; 103a, 103b: combiner; AM: adhesive; AX: optical axis; CR: focusing reflection unit; CT: adhesive; CV: filling space; DIS: direct virtual image optical system; EP: exit pupil; EY: eye; FOV: field of view; IS: imaging optical system; LA: liquid; LP: image light shielding unit; M1: transmitted light; M2: reflected light; MA: adhesive; ML: image light; OL: external light; PP: pupil position; US: wearer. DETAILED DESCRIPTION

[0023] [First embodiment]

[0024] Below, refer to Figure 1 , Figure 2 etc., a first embodiment of the virtual image display device etc. of the present invention is described.

[0025] Figure 1 1 is a diagram for explaining a wearing state of a head mounted virtual image display device (hereinafter also referred to as a head mounted display or HMD) 200. The HMD 200 allows an observer or wearer US wearing the HMD 200 to recognize a video image as a virtual image. Figure 1 In the above, X, Y, and Z are orthogonal coordinate systems, the +X direction corresponds to the lateral direction in which the two eyes EY of the observer or wearer US wearing the HMD 200 are arranged, the +Y direction corresponds to the upward direction orthogonal to the lateral direction in which the two eyes EY of the wearer US are arranged, and the +Z direction corresponds to the front direction or the front direction of the wearer US. The ±Y directions are parallel to the vertical axis or the vertical direction.

[0026] The HMD 200 includes a first virtual image display device 100A of a direct virtual image type for the right eye, a second virtual image display device 100B of a direct virtual image type for the left eye, a pair of support devices 100C in the shape of temples that support these virtual image display devices 100A and 100B, and a user terminal 90 as 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 covers the front of the eyes in the shape of a glasses lens. 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 covers the front of the eyes in the shape of a glasses lens. The support device 100C is a wearing component worn 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 left-right inverted, and detailed description of the second virtual image display device 100B is omitted.

[0027] Figure 21 is a side cross-sectional view for explaining 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 component 80a. The first image forming element 11a is also referred to as 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 referred to as a direct virtual image optical system DIS. The imaging optical system IS includes a first lens 30, a first flat plate-shaped member 40, and a second flat plate-shaped member 50. The first lens 30 has a function as a protective glass for protecting the display surface 11d of the display element 11. The first flat plate-shaped member 40 guides the image light ML emitted from the display element 11 to the second lens 53 of the second flat plate-shaped member 50. The second flat member 50 reflects the image light ML from the first flat member 40 toward the pupil position PP or the eye EY by partially returning the image light ML to the first flat member 40, and makes the external light OL incident on the pupil position PP via the first flat member 40. The first lens 30, the first flat member 40, and the second flat member 50 each function as a lens having a positive refractive power.

[0028] Although detailed description is omitted, the second virtual image display device 100B includes a second image forming element 11b, a second display unit 20b, and a second circuit component 80b. The second image forming element 11b is the same as the first image forming element 11a, the second display unit 20b is the same as the first display unit 20a, and the second circuit component 80b is the same as the first circuit component 80a.

[0029] 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-shaped member 40 via the first lens 30. The first image forming element 11a is accommodated and supported by the housing 71. The first image forming element 11a is, for example, an organic EL (Organic Electro-Luminescence) display, which forms a color static image or dynamic 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 by a display device using an inorganic EL, an organic LED, an LED array, a laser array, a quantum dot light-emitting element, etc. The first image forming element 11a is not limited to a self-luminous image light generating device, and can also be composed of other light modulating elements such as LCDs, and an image is formed by illuminating the light modulating element with a light source such as a backlight. As the first image forming element 11a, LCOS (Liquid crystal on silicon, LCoS is a registered trademark), a digital micromirror device, etc. can also be used instead of LCD. In addition, in the first virtual image display device 100A, the optical device other than the first circuit component 80a is referred to as an optical unit 100. The optical unit 100 includes a direct virtual image type optical system, and can also be said to be a part equivalent to the direct virtual image optical system DIS constituting the first virtual image display device 100A.

[0030] The first display unit 20a includes a first lens 30, a first flat plate-shaped member 40, a polarization separation film 45, and a second flat plate-shaped 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 planar light incident surface 30f joined 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 set as an aspherical surface having an axisymmetric shape. The first lens 30 can be considered as a parallel plate 31 and a lens portion 32. By ensuring that the thickness of the parallel plate 31 is greater than a predetermined thickness, foreign matter attached to the surface of the first lens 30 is less likely to become conspicuous. The lens portion 32 is a plano-convex lens with positive refractive power. One surface of the plano-convex lens has a planar shape, and the other surface has a convex shape. The first lens 30 is made of, for example, fused silica, and has a relatively low refractive index.

[0031] The first flat plate-shaped member 40 has a first prism 41 in the form of a parallel flat plate and a second prism 42 in the form of a parallel flat plate. The first prism 41 and the second prism 42 are joined by inclined surfaces 41d and 42d. The member formed by joining the first prism 41 and the second prism 42 is called a prism light guide member 48. The prism light guide member 48 has the appearance of a parallel flat plate. A planar polarization separation film 45 is formed on the inclined surface 41d formed on the lower side of the first prism 41. The member formed by combining the prism light guide member 48 and the second flat plate-shaped member 50 described later is equivalent to Figure 1 The first combiner 103a.

[0032] The first prism 41 has a quadrangular prism-shaped outer shape and a trapezoidal longitudinal section. The first prism 41 guides the image light ML and has an incident optical surface 41a, an inner side surface 41b, an outer side surface 41c, and an inclined surface 41d. Here, the incident optical surface 41a is inclined downward in the front direction as a whole, and the optical axis passing through the incident optical surface 41a extends in the direction between the +Z direction as the front and the +Y direction as the top. As a result, it is easy to arrange the first image forming element 11a as the display element 11 at a position closer to the outside side than the inner side surface 41b, and the angle of the image light ML propagating 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, for example, a spherical surface, but can be set as an axisymmetric aspherical surface. It can be considered that the first prism 41 has a lens portion 44 including the incident optical surface 41a. The lens portion 44 is a convex plano lens with positive refractive power. The inner side surface 41b and the outer side surface 41c are parallel to each other and extend perpendicularly to the optical axis AX between the pupil position PP. The inner side surface 41b and the outer side surface 41c internally reflect the image light ML (i.e., reflect it on the inner side of the object surface), but it is particularly preferred to perform total reflection. The inner side surface 41b can improve the scratch resistance or abrasion resistance by implementing a hard coating. The inclined surface 41d is a plane. Regarding the inclined surface 41d, an acute angle is formed relative to the outer side surface 41c, specifically, an angle of 25° to 32°, which will be described in detail later. In addition, the interval 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 formed of, for example, a resin material and has a refractive index higher than the refractive index of the first lens 30.

[0033] The number of times the image light ML is reflected in the first prism 41 is once on the inner side surface 41b, once on the outer side surface 41c, and further once on the polarization separation film 45 described later. By setting the number of times the image light ML is reflected in the first prism 41 to 2, the viewing angle of the image light ML, the pupil position PP or its opening PPa can be increased, and the mixing of lights having different reflection times in the first prism 41 can be avoided. The image light ML reflected by the inner side surface 41b and the outer side surface 41c does not form an intermediate image in the first display unit 20a or the imaging optical system IS, so the degree of divergence is suppressed compared to the initial divergence state emitted from the first image forming element 11a, but it is incident on the inner side surface 41b and the outer side surface 41c in a still divergent state, and the divergent state is maintained.

[0034] The second prism 42 has a quadrangular prism-shaped outer shape similarly to the first prism 41, and has a trapezoidal longitudinal section. The second prism 42 allows the image light ML to pass through, and has an inner side surface 42b, an outer side surface 42c, and an inclined surface 42d. Here, the inner side surface 42b and the outer side surface 42c are parallel to each other and extend perpendicularly to the optical axis AX between the pupil position PP. For the inner side surface 42b, by applying a hard coating, it is possible to improve the scratch resistance or abrasion resistance. The second prism 42 is formed of, for example, a resin material and has a refractive index equal to that of the first prism 41.

[0035] 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 an adhesive CT for bonding. The polarization separation film 45 is formed by a dielectric multilayer film, and when the image light ML includes s-polarized light s, the image light ML of s-polarized light s is efficiently reflected, and when the image light ML includes p-polarized light p, the image light ML of p-polarized light p is efficiently transmitted. The polarization separation film 45 only needs to selectively reflect the image light ML according to the polarization direction, for example, it can also be a wire grid type polarizer. The polarization separation film 45 only needs to be a flat surface that does not affect the imaging. In addition, the polarization separation film 45 can also have a convex or concave micro-curved surface that does not affect the imaging. The polarization separation film 45 can improve the scratch resistance or abrasion resistance by applying a hard coating on the surface. In addition, a filler having transmissivity may be filled between the polarization separation film 45 and the inclined surface 41d 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 supporting member or the like to maintain the joined state. In addition, the polarization separation film 45 may be formed integrally on the inclined surface 42d of the second prism 42 instead of being formed on the inclined surface 41d of the first prism 41.

[0036] When the reflection angle of the image light ML on the optical axis AX in the first prism 41 is β0, the tilt angle θ of the polarization separation film 45 is greater than 90°-β0. As a premise that the polarization separation film 45 does not hinder the path of the image light ML, when the maximum reflection angle of the image light ML is βmax, the tilt angle θ of the polarization separation film 45 is preferably less than βmax. The reflection angle β0 of the image light ML is equivalent to the angle formed by the normal line of the inner side surface 41b and the optical axis AX passing through the incident optical surface 41a, which is an acute angle. That is, the optical axis AX of the incident optical surface 41a extends in a direction less than 90° relative to the normal line of the inner side surface 41b. In addition, the tilt angle θ of the polarization separation 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, which will be described in detail later. In addition, the reflection angle β0 corresponds to the reflection incident angle γ described later, which is the reflection incident angle of the image light ML on the optical axis AX.

[0037] The second flat member 50 includes a thin plate-shaped quarter-wave plate 51 and a cover member 52. The quarter-wave plate 51 is a crystal having an optical axis between the X direction and the Y direction, and converts the image light ML of the s-polarized light s reflected by the polarization separation film 45 into circularly polarized light c, and converts the image light ML of the circularly polarized light c reflected by the cover member 52 into p-polarized light p. The cover member 52 includes a plano-convex second lens 53, a concave-planar compensation lens 54, a compensation plate 55 provided around the compensation lens 54, and a transmissive reflector 56.

[0038] An angle selection film 60 is provided between the prism light guide member 48 and the second flat plate member 50. That is, the angle selection film 60 is provided between the outer side surface 48c of the prism light guide member 48 or the outer side surfaces 41c, 42c of the first flat plate member 40 and the inner side surface 50c of the second flat plate member 50. By providing the angle selection film 60 on the outer side surface 48c of the prism light guide member 48, it is not necessary to provide a clearance between the outer side surfaces 41c, 42c of the first flat plate member 40 and the inner side surface 50c of the second flat plate member 50. Thus, the second flat plate member 50 can be directly bonded to the angle selection film 60. Specifically, the angle selection film 60 and the quarter wavelength plate 51 of the second flat plate member 50 are bonded by an adhesive. In addition, the angle selection film 60 is preferably provided on the outer side surface 41c of the first prism 41 in the first flat plate member 40, in particular.

[0039] The angle selective film 60 is an angle-dependent separation film showing different separation characteristics according to the incident angle of light. The angle selective film 60 functions as a plane transmissive reflection surface that reflects the image light ML reflected by the inner side surface 41b of the first prism 41 and transmits the image light ML reflected by the polarization separation film 45.

[0040] Figure 3 is a diagram showing the reflection and transmission characteristics of the angle selection film 60. Figure 3 In FIG. 6 , the horizontal axis is the incident angle (unit: °) of the light incident on the outer side surface 41c of the first prism 41, and the vertical axis is the reflectivity (unit: %) relative to the incident angle. Symbol LR represents red light, symbol LG represents green light, and symbol LB represents blue light. The angle selection film 60 is a film that transmits the image light ML when the incident angle is 20° or less, and reflects the image light ML when the incident angle is 40° or more.

[0041] Figure 4 FIG. 4 is a partial enlarged view for explaining light rays transmitted or reflected in the first prism 41 of the prism light guide member 48. Figure 4 As shown by the dotted line L1, the viewing angle in the upward direction of the field of view is defined as +, such as Figure 4 As shown by the single-dot dash line L2, the viewing angle in the downward direction of the field of view angle FOV is defined as -. In the first prism 41 of the prism light-guiding component 48, the incident angle of the transmitted light M1 incident on the angle selection film 60 (transmission incident angle) is α, and the incident angle of the reflected light M2 incident on the angle selection film 60 (reflection incident angle) is γ. In addition, the angle (PBS angle) formed by the surface of the polarization separation film 45 and the surface of the angle selection film 60 is θ. Here, the angles α, γ, and θ are set assuming that the light advances from the pupil position PP. The refractive index of the first prism 41 is 1.75. Figure 5 This is a table showing examples of various angles of viewing angle in the upward direction with respect to the field of view angle FOV. Figure 6 This is a table showing examples of various angles of viewing angle in the downward direction with respect to the field of view angle FOV.

[0042] The relationship between the field of view angle FOV and the polarization separation film 45 is described below. The angle (PBS angle θ) of the inclined surface 41d of the first prism 41 formed with the polarization separation film 45 needs to be reduced as the field of view angle FOV increases so that the reflected light M2 of the angle selection film 60 does not intersect the surface of the polarization separation film 45. Figure 6 As shown, the reflection incident angle γ is limited to a range in which the reflected light M2 incident on the angle selection film 60 is reflected by the angle selection film 60 , and specifically, is limited to be greater than 40°.

[0043] Figure 5 and Figure 6 The transmission incident angle α and the reflection incident angle γ shown can be expressed by the following equations (1) and (2).

[0044] The PBS angle θ is adjusted so as to satisfy the following equations (3) and (4).

[0045]

[0046] y=2*θ+α.(2)

[0047] Here, the lower limit value of the PBS angle θ is expressed by the following formula.

[0048] 0>(90-α) / 3(3)

[0049] On the other hand, there are conditions for reflecting the reflected light M2 incident on the angle selection film 60. In the present embodiment, reflection is performed 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 conditions are obtained.

[0050] 0>(40-α) / 2(4)

[0051] The angle selective film 60 is a dielectric multilayer film formed by stacking multiple dielectric layers with different refractive indices. The angle selective film 60 has a film structure with almost no absorption and no polarization dependence. Specifically, the angle selective film 60 is composed of a dielectric multilayer film formed by alternately stacking transparent films with high refractive indexes (such as TiO2 and HfO2) and transparent films with low refractive indexes (such as SiO2 and MgF2).

[0052] In the cover part 52, the second lens 53 is thin but has positive refractive power, and has a flat surface 53f joined to the 1 / 4 wavelength 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 set as an axisymmetric aspherical surface. The compensation lens 54 is thin but has positive refractive power, and has a concave surface 54f and a flat surface 54g facing the second lens 53. The compensation plate 55 is a parallel plate and has a pair of flat surfaces 55f and 55g. Here, the concave surface 54f of the compensation lens 54 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 continuous on the same plane. The transmissive reflector 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 component in which the second lens 53 and the transmissive reflector 56 are combined is called a focusing reflection part CR.

[0053] The second lens 53 is formed by filling an adhesive such as a photocurable resin in a filling space formed between the region corresponding to the compensation lens 54 in the cover part 52 and the 1 / 4 wavelength plate 51. After the photocurable resin is filled, it is photocured. As the photocurable resin, for example, an acrylic resin adhesive that is cured by ultraviolet light or visible light can be listed, specifically, LOCTITE (registered trademark) AA3301 (manufactured by Henkel Co., Ltd.) can be listed. In addition, a thermosetting resin can also be used as an adhesive.

[0054] The size of the second lens 53 is 20 mm to 25 mm in diameter, specifically about 22 mm. The thickness of the center of the second lens 53 is 3 mm or less, preferably 1 mm to 1.7 mm. The thickness of the edge or periphery of the second lens 53 is 0.2 mm to 0.5 mm.

[0055] When the thickness of the second lens 53 is about 1 mm, it is difficult to manufacture it by grinding or injection molding. Therefore, in the present embodiment, in the cover part 52, the concave surface of the compensation lens 54 which is opposite to the second lens 53 is used as a molding mold, and the second lens 53 is molded when the first display unit 20a is assembled. Specifically, the cover part 52 other than the second lens 53, that is, the compensation lens 54, is docked with the 1 / 4 wavelength plate 51, and the second lens 53 is formed by filling the filling space with an adhesive through a flow path not shown. By curing the adhesive, the second lens 53 is molded, and the 1 / 4 wavelength plate 51 is bonded to the cover part 52. Thus, even if the second lens 53 is thin, it can be easily formed. The adhesive uses an adhesive having a refractive index equal to that of the compensation lens 54.

[0056] The compensation lens 54 and the compensation plate 55 are formed of 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 and the like is lower than the refractive index of the first prism 41. The compensation lens 54 and the compensation plate 55 are an optical element 58 integrally formed of the same resin material.

[0057] 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 and the compensation plate 55 passes through them without being affected by the lens effect of the compensation lens 54 and the steps existing on the outer edge of the compensation lens 54. The planes 54g and 55g of the compensation lens 54 and the compensation plate 55 may be provided with an anti-reflection film or a hard coating. The external light OL that has passed through the compensation plate 55 passes through the upper, lower, left, and right sides of the compensation lens 54, and enters from the surrounding area outside the incident area of ​​the image light ML corresponding to the compensation lens 54, that is, from the compensation plate 55. As a result, a wide perspective field of view can be ensured with respect to the outside world. The field of view of the external light OL is set to, for example, about 40° upward and about 40° downward.

[0058] As described above, from the viewpoint of ensuring the viewing angle, the diameter of the second lens 53 is set to 20 mm to 25 mm. In addition, the thickness of the first flat member 40 or the prism light guide member 48 in the Z direction is 6 mm to 8 mm, and the distance from the inner side surfaces 41 b and 42 b of the first flat member 40 to the pupil position PP is about 12 mm to 13 mm. Therefore, the angle range of the image light ML incident on the pupil position PP, that is, the viewing angle (diagonal angle), can be set to about 40°.

[0059] The transmissive reflector 56 is a half mirror that partially reflects the image light ML that has passed through the second lens 53 and partially transmits the external light OL. The transmissive reflector 56 reflects the image light ML that has been reflected by the polarization separation film 45 of the first flat plate-shaped member 40 and has passed through the angle selection film 60, the 1 / 4 wavelength plate 51, and the second lens 53 toward the pupil position PP. The transmissive reflector 56 is a concave mirror that covers the pupil position PP where the eye EY or the pupil is arranged 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 an eye point or an eye box, and corresponds to the exit pupil EP of the first display unit 20a.

[0060] The transmissive reflector 56 transmits a part of the external light OL, so that the external world can be observed in perspective, and the virtual image can be overlapped with the external image. At this time, the external light OL passes through the first flat member 40 and the second flat member 50, but the flat members 40 and 50 do not produce a lens effect on the external light OL. From the viewpoint of ensuring the brightness of the image light ML and facilitating the observation of the external image based on perspective, the reflectivity of the transmissive reflector 56 to the image light ML and the external light OL is greater than 10% and less than 50% within the assumed incident angle range of the image light ML. The transmissive reflector 56 is formed, for example, by a dielectric multilayer film, which is composed of a plurality of dielectric layers with adjusted film thickness. The transmissive reflector 56 can also be a single-layer film or a multilayer film of a metal such as Al or Ag with adjusted film thickness. The transmissive reflector 56 is formed, for example, by lamination using vapor deposition.

[0061] In the first virtual image display device 100A, the first lens 30, the lens unit 44, the second lens 53 and the transmissive reflector 56 each have a positive refractive power and have a tendency to converge divergent light. The first lens 30, the lens unit 44, the second lens 53 and the transmissive reflector 56, including the main body of the first prism 41, the second prism 42, etc., function as an imaging optical system IS or a direct virtual image optical system DIS such as a single-type microscope type microscope that forms an erect image. As a result, the real image formed on the display surface 11d of the first image forming element 11a can be formed into a virtual image projected to infinity, for example, or the real image formed on the display surface 11d can be formed into 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 transmissive reflector 56, the focal length of the imaging optical system IS can be shortened to achieve a desired magnification.

[0062] Reference Figure 7, the longitudinal dimension ay of the first flat plate-shaped member 40 or the second flat plate-shaped member 50 is, for example, 34 mm, and the lateral dimension ax is, for example, 40 mm. The thickness az of the first flat plate-shaped member 40 in the front-to-back direction is, for example, about 7 mm, and the total thickness of the first flat plate-shaped member 40 and the second flat plate-shaped member 50 is suppressed to about 7.5 mm. In the first flat plate-shaped member 40, an upper plane 40u is provided on the left and right of the incident optical surface 41a. Light is not allowed to be incident on the upper plane 40u. On the upper plane 40u, from the viewpoint of preventing stray light, a light-shielding body (not shown) can be arranged to cover it opposite to the upper plane 40u, or a light-shielding body can be applied. A light-shielding body or the like that covers the horizontal plane 40v and the lower plane 40w can also be provided. A light-shielding body or the like that covers the second flat plate-shaped member 50 can also be provided around it.

[0063] Reference Figure 8 , the shapes of the first image forming element 11a and the first lens 30 are described. Figure 8 In the figure, region AR1 represents the state of observing the first lens 30 etc. from the front +Z side in the oblique upward direction, region AR2 represents the state of observing the first lens 30 etc. from the lower -Y side in the oblique forward direction, and region AR3 represents the state of observing the first lens 30 etc. from the lateral +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.

[0064] The curvature radius of the convex light emitting surface 30g of the first lens 30 is, for example, 20 mm. Figure 2 The curvature radius of the incident optical surface 41 a of the illustrated first prism 41 is, for example, 14 mm, and the curvature radius of the transmissive reflective mirror 56 is, for example, 47 mm.

[0065] return Figure 2, the optical path is explained, and the image light ML from the first image forming element 11a is incident on 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 portion 44. In the optical path passing through the first prism 41, the image light ML does not form an intermediate image, and is reflected in sequence by the inner side surface 41b of the first prism 41 and the outer side surface 41c of the first prism 41, and the s component in the image light ML is reflected by the polarization separation film 45. The image light ML of s-polarized light s reflected by the polarization separation film 45 passes through the outer side surface 41c of the first prism 41 and the angle selection film 60, passes through the 1 / 4 wavelength plate 51 of the second flat plate-shaped member 50, and thus becomes circularly polarized light c, and is incident on the transmissive reflector 56. The image light ML of the circularly polarized light c incident on the transmissive reflector 56 passes through the second lens 53 and is partially reflected by the transmissive reflector 56, and passes through the quarter wavelength plate 51 again in a state of being collimated by the second lens 53. Thus, the image light ML that has passed through the quarter wavelength plate 51 becomes p-polarized light p and enters the first prism 41 from the outer side surface 41c via the angle selection film 60, passes through the polarization separation film 45, and is emitted to the outside of the second prism 42 via the inner side surface 42b. The image light ML emitted to the outside of the second prism 42 is incident on the pupil position PP where the eye EY or pupil of the wearer US is arranged. At the pupil position PP, not only the image light ML reflected by the transmissive reflector 56 but also the external light OL that has passed through the transmissive reflector 56 and the external light OL that has passed through the compensation plate 55 are incident. That is, the wearer US wearing the first virtual image display device 100A can observe the virtual image based on the image light ML in a superimposed manner with the external image.

[0066] Reference Fig. 9 and Fig.10 , an example of the structure and assembly of the first display unit 20a constituting the first virtual image display device 100A is described. Fig. 9 In FIG. 1 , regions BR1 to BR4 are perspective views for explaining the assembly process of the first display unit 20a. Fig.10 In FIG. 1 , regions CR1 to CR5 are cross-sectional views for explaining the assembly process of the first display unit 20a. Fig. 9 As shown in the area BR1, the first prism 41 and the second prism 42 are prepared. The first prism 41 and the second prism 42 are formed by, for example, resin injection molding. The first prism 41 is formed with an incident optical surface 41a, an inner side surface 41b, an outer side surface 41c, etc. The second prism 42 is formed with an inner side surface 42b, an outer side surface 42c, etc. On the inclined surface 41d of the first prism 41 on one side, a polarization separation film 45 is formed by vacuum evaporation or other methods. Fig. 9 Area BR2 and Fig.10As shown in the region CR1 of FIG. 1 , the first prism 41 and the second prism 42 are joined at the inclined surfaces 41d and 42d to obtain the first flat plate-shaped member 40. Fig.10 As shown in the region CR2 of the first flat member 40, an angle selection film 60 is formed on the outer side surfaces 41c and 42c of the first flat member 40 by vacuum evaporation or other methods. Fig. 9 Area BR3 and Fig.10 As shown in the region CR3 of the first planar member 40, the quarter-wave plate 51 is bonded to face the outer side surfaces 41c and 42c of the first planar member 40. Fig. 9 Area BR4 and Fig.10 As shown in the region CR4 of the optical element 58, the compensating plate 55 and the quarter wavelength plate 51 are butted against each other. Thus, a filling space CV is formed between the compensating lens 54 and the quarter wavelength plate 51 as a molding die for the second lens 53. A transmissive reflector 56 is formed on the concave surface of the compensating lens 54 facing the quarter wavelength plate 51. Next, as shown in FIG. Fig.10 As shown in the region CR5 of the optical element 58, an adhesive MA as a 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 adhesive MA is filled into the filling space CV corresponding to the second lens 53. Then, the filled adhesive MA is cured by irradiating ultraviolet light UV or the like. Thus, the second lens 53 is formed in a joined state between the 1 / 4 wavelength plate 51 and the compensation lens 54. Through the above, the assembly of the first display unit 20a is completed. In addition, when the compensation plate 55 and the 1 / 4 wavelength plate 51 are docked, they can also be joined by an adhesive.

[0067] The virtual image display device 100A, 100B or the optical unit 100 of the first embodiment described above is a direct virtual image type virtual image display device, which comprises: a display element 11, which emits image light ML; a first lens 30, which has a positive refractive power, and the image light ML from the display element 11 is incident on the first lens 30; 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 flat plate-shaped prism light guide component 48; a planar polarization separation film 45, which is arranged at the junction of the first prism 41 and the second prism 42, and selectively reflects the image light ML guided in the first prism 41 according to the polarization direction; an angle selection film 60, which is arranged in the prism light guide component 48 to reflect the image light ML guided in the first prism 41 The outer side surface on which the image light ML reflected by the polarization separation film 45 is incident shows different separation characteristics according to the incident angle of the image light ML; the plano-convex second lens 53 has a plane 53f arranged opposite to the angle selection film 60; the transmissive reflector 56 is arranged on the convex surface 53g of the second lens 53, and partially reflects the image light ML reflected by the polarization separation film 45 toward the polarization separation film 45; the 1 / 4 wavelength plate 51 is arranged between the angle selection film 60 and the plane 53f of the second lens 53; and the compensation lens 54 has a concave surface 54f and a plane 55g parallel to the outer side surface 41c of the first prism 41, the concave surface 54f has a shape that reverses the convex surface 53g of the second lens 53, and is joined to the convex surface 53g via the transmissive reflector 56.

[0068] In the above-mentioned virtual image display device 100A, 100B or optical unit 100, a virtual image is directly formed without forming an intermediate image, so the refractive power is ensured by the first lens 30, the second lens 53 and the transmissive reflector 56, which can suppress the increase in the optical path length and ensure the magnification, thereby avoiding the enlargement of the optical system.

[0069] [Second embodiment]

[0070] Hereinafter, a virtual image display device according to a second embodiment will be described. The virtual image display device according to the second embodiment is obtained by partially modifying the virtual image display device according to the first embodiment, and description of the same parts as those of the virtual image display device according to the first embodiment will be omitted.

[0071] like Fig.11As shown, the second lens 53 is formed by the liquid LA filled in the filling space CV between the compensation lens 54 and the quarter-wave plate 51. The liquid LA is a refractive index adjustment member having the same refractive index as the compensation lens 54. By setting the material of the second lens 53 to the liquid LA having the same refractive index as the compensation lens 54, it is effective when the refractive index equal to that of the compensation lens 54 cannot be obtained by using an adhesive. As the refractive index adjustment member, for example, Cargill standard refractive liquid (manufactured by MORITEX Co., Ltd.), 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. can be cited. In addition, the refractive index adjustment member can also use a refractive index matching film (manufactured by Tomogawa Paper Co., Ltd.), specifically, Fit Well (registered trademark, refractive index: 1.46).

[0072] In the cover part 52, the concave surface of the compensation lens 54, which is opposite to the second lens 53, is used as a molding die, and the quarter wavelength plate 51 and the compensation plate 55 are bonded together by an adhesive. A flow path for injecting the material of the second lens 53 is formed in the compensation lens 54. After the quarter wavelength plate 51 and the compensation plate 55 are bonded together, the refractive index adjusting component, which is the liquid LA, is filled into the filling space formed between the quarter wavelength plate 51 and the compensation lens 54 through the flow path, and the periphery of the liquid LA is sealed by an adhesive. Thus, even if the second lens 53 is thin, it can be easily formed. The refractive index adjusting component uses a component having a refractive index equivalent to that of the compensation lens 54.

[0073] Hereinafter, an example of the structure and assembly of the first display unit 20a constituting the first virtual image display device 100A will be described. Fig.11 In FIG. 2 , regions DR1 to DR5 are cross-sectional views for explaining the assembly process of the first display unit 20a. Fig.11 As shown in the region DR1 of FIG. 1 , the first prism 41 and the second prism 42 are joined at the inclined surfaces 41d and 42d to obtain the first flat plate-shaped member 40. Fig.11 As shown in the region DR2 of the first flat member 40, an angle selection film 60 is formed on the outer side surfaces 41c and 42c of the first flat member 40 by vacuum evaporation or other methods. Fig.11 As shown in the region DR3 of the first flat plate 40, the quarter-wave plate 51 is bonded to face the outer side surfaces 41c and 42c of the first flat plate 40. Fig.11As shown in the area DR4 of the optical element 58, the compensation plate 55 and the 1 / 4 wavelength plate 51 are butted against each other and bonded using an adhesive AM. Specifically, the adhesive AM is a light-curing resin such as an ultraviolet curing resin, and the compensation plate 55 and the 1 / 4 wavelength 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 1 / 4 wavelength plate 51 as a shape retaining frame for the second lens 53. A transmissive reflector 56 is formed on the concave surface of the compensation lens 54 opposite to the 1 / 4 wavelength plate 51. Next, as shown in Fig.11 As shown in the region DR5 of the optical element 58, 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 filling space CV corresponding to the second lens 53 is filled with liquid LA. Thereafter, the flow path is sealed with an adhesive. Thus, the second lens 53 is formed between the 1 / 4 wavelength plate 51 and the compensation lens 54. As described above, the assembly of the first display unit 20a is completed.

[0074] [Third embodiment]

[0075] Hereinafter, a virtual image display device according to a third embodiment will be described. The virtual image display device according to the third embodiment is obtained by partially modifying the virtual image display device according to the first embodiment, and description of the same parts as those of the virtual image display device according to the first embodiment will be omitted.

[0076] exist Fig.12 In the case of the first virtual image display device 100A shown, in the first display unit 20a, for example, an s-polarized light transmitting polarizing plate 12 is arranged between the first lens 30 and the first image forming element 11a. However, the s-polarized light transmitting polarizing plate 12 is not functionally essential. In addition, in the first display unit 20a, a third flat plate-shaped member 150 is added to the external side of the second flat plate-shaped member 50. The third flat plate-shaped member 150 is an image light shielding portion LP, and includes an outer 1 / 4 wavelength plate 151 provided on the external side of the condensing reflection portion CR and a polarizing plate 59 provided on the external side of the outer 1 / 4 wavelength plate 151 and selectively absorbing the image light ML transmitted through the 1 / 4 wavelength plate 151 according to the polarization direction. That is, in the first display unit 20a, the inner 1 / 4 wavelength plate 51 and the outer 1 / 4 wavelength plate 151 are arranged between the inner polarization separation film 45 and the outer polarizing plate 59.

[0077] Reference Fig.13 , from the first image forming element 11a (refer to Fig.12) contains only s-polarized light. The s-polarized image light ML incident on the polarization separation film 45 is reflected by the polarization separation film 45 without waste, passes through the inner 1 / 4 wavelength plate 51 to become circularly polarized light, and is incident on the transmissive reflector 56. The circularly polarized image light ML incident on the transmissive reflector 56 is partially reflected by the transmissive reflector 56, and passes through the inner 1 / 4 wavelength plate 51 again in the reverse direction. The image light ML passing through the inner 1 / 4 wavelength plate 51 in the reverse direction becomes p-polarized light and passes through the polarization separation film 45, and is incident on the pupil position PP (refer to Fig.12 ). On the other hand, the circularly polarized image light ML that has passed through the transmissive reflector 56 passes through the outer 1 / 4 wavelength plate 151 to become p-polarized light, and is incident on the polarizing plate 59, and is almost blocked by the polarizing plate 59. That is, the image light ML is blocked by the third flat plate member 150 and does not leak to the outside. That is, it is possible to prevent the image light ML from being observed from the outside, so that privacy can be ensured.

[0078] On the other hand, the external light OL incident on the polarizing plate 59 passes through the polarizing plate 59 to become only s-polarized light, passes through the outer 1 / 4 wavelength plate 151 to become circularly polarized light, and partially passes through the transmissive reflector 56. The circularly polarized external light OL that has partially passed through the transmissive reflector 56 passes through the inner 1 / 4 wavelength plate 51 to become p-polarized light, passes through the polarization separation film 45, and enters the pupil position PP (see Fig.12 ).

[0079] Fig.14 Yes Description Fig.12 and Fig.13 FIG. 1 is a diagram showing a modified example of the first virtual image display device 100A. In this case, it is assumed that Fig.12 The polarizing plate 59 of the third flat-plate member 150 shown transmits s-polarized light and reflects p-polarized light.

[0080] To Fig.13 The difference between the two is described below. The circularly polarized image light ML that partially passes through the transmissive reflector 56 passes through the outer 1 / 4 wavelength plate 151 to become p-polarized light, and is mostly reflected by the polarizing plate 59 without leaking out of the polarizing plate 59. In addition, the p-polarized image light ML reflected by the polarizing plate 59 passes through the outer 1 / 4 wavelength plate 151 again in the reverse direction. The p-polarized image light ML that passes through the outer 1 / 4 wavelength plate 51 becomes circularly polarized light and is partially reflected by the transmissive reflector 56, but does not pass through the polarizing plate 59. The circularly polarized image light ML that partially passes through the transmissive reflector 56 passes through the inner 1 / 4 wavelength plate 51 again in the reverse direction. The image light ML that passes through the inner 1 / 4 wavelength plate 51 becomes s-polarized light and is reflected by the polarization separation film 45, and returns to the direction of the first image forming element 11a.

[0081] On the other hand, the external light OL incident on the polarizing plate 59 passes through the polarizing plate 59 to become s-polarized light, passes through the outer 1 / 4 wavelength plate 151 to become circularly polarized light, and partially passes through the transmissive reflector 56. The circularly polarized external light OL partially passing through the transmissive reflector 56 passes through the inner 1 / 4 wavelength plate 51 to become p-polarized light, passes through the polarization separation film 45, and enters the pupil position PP (see Fig.12 ). In addition, although the p-polarized light in the external light OL is reflected by the polarizing plate 59, this does not cause any particular problem, and can prevent the surface of the first display portion 20a from becoming too dark.

[0082] 〔Variations and others〕

[0083] As mentioned above, the present invention has been described based on the embodiment, but the present invention is not limited to the above-mentioned embodiment, and can be implemented in various forms within the scope not departing from the gist of the present invention. For example, the following modifications are also possible.

[0084] In the above, the HMD 200 includes the first virtual image display device 100A and the second virtual image display device 100B. However, the HMD 200 may support a single first virtual image display device 100A or a single second virtual image display device 100B in front of the eyes via the support device 100C.

[0085] In the assembling method of the first display unit 20 a , the second lens 53 is formed during the assembling process, but the second lens 53 separately manufactured by injection molding or the like may be bonded.

[0086] The compensating plate 55 can be omitted from the cover member 52 . In this case, the quarter-wave plate 51 is disposed only within the range of the second lens 53 , and the second lens 53 is covered with the compensating lens 54 .

[0087] The incident optical surface 41 a may be omitted in the first prism 41 of the first flat member 40. In this case, the optical system is obtained by omitting the lens unit 44.

[0088] The first lens 30 is not limited to being bonded to the first image forming element 11 a , and may be disposed separately from the first image forming element 11 a .

[0089] The first prism 41 and the second prism 42 may be formed of glass instead of being formed of a resin material.

[0090] The first image forming element 11 a may be a scanning type display device including a laser light source and a scanning mirror.

[0091] The virtual image display device in a specific embodiment is a direct virtual image type virtual image display device, which comprises: a display element, which emits image light; a first lens, which has a positive refractive power, and the image light from the display element is incident on the first lens; a first prism, and the image light passing through the first lens is incident on the first prism; a second prism, which is joined with the first prism to form a parallel flat plate-shaped prism light guide component; a planar polarization separation film, which is arranged at the junction of the first prism and the second prism, and selectively reflects the image light guided in the first prism according to the polarization direction; an angle selection film, which is arranged in the prism light guide component at the first prism. The outer side surface on which the image light guided by the prism and reflected by the polarization separation film is incident shows different separation characteristics according to the incident angle of the image light; a plano-convex second lens having a plane arranged opposite to the angle selection film; a transmissive reflector formed on the convex surface of the second lens, which partially reflects the image light reflected by the polarization separation film toward the polarization separation film; a 1 / 4 wavelength plate arranged between the angle selection film and the plane of the second lens; and a compensation lens having a concave surface and a plane parallel to the outer side surface of the first prism, the concave surface having a shape obtained by inverting the convex surface of the second lens, and being joined to the convex surface via the transmissive reflector.

[0092] In the above-mentioned virtual image display device, since a virtual image is formed directly without forming an intermediate image, the refractive power is ensured by the first lens, the second lens and the transmissive reflector, which can suppress the increase in the optical path length and ensure the magnification, thereby avoiding the enlargement of the optical system.

[0093] In a specific embodiment of a virtual image display device, the first lens, the prism light guide component, the polarization separation film, the angle selection film, the second lens, the transmissive reflector and the quarter-wave plate constitute a single-microscope type imaging optical system for forming an erect image, and the first prism diverges the image light and performs two internal reflections. In this case, it is easy to shorten the distance from the display element to the transmissive reflector, and the prism light guide component can be miniaturized, and the display element and the first lens can also be miniaturized.

[0094] In a specific embodiment of the virtual image display device, the angle selection film is composed of a dielectric multilayer film, transmits image light when the incident angle to the angle selection film is 20 degrees or less, and reflects image light when the incident angle to the angle selection film is 40 degrees or more.

[0095] In a specific embodiment, the virtual image display device further includes a compensation plate disposed around the compensation lens and extending parallel to the prism light guide member. In this case, the external light incident on the periphery of the compensation lens can be observed in the same manner as the external light incident on the compensation lens.

[0096] In a specific embodiment of the virtual image display device, the angle selection film is bonded to the quarter wavelength plate.

[0097] In a specific embodiment of the virtual image display device, the first lens has a planar light incident surface and a convex light exit surface bonded to the display element. 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 a predetermined thickness, foreign matter attached to the surface of the first lens is less likely to become conspicuous.

[0098] In a virtual image display device in a specific embodiment, the first prism has an incident optical surface with positive refractive power, and the incident optical surface has an optical axis extending in a direction less than 90 degrees relative to the normal line of the inner surface. In this case, it is easy to arrange the display element at a position closer to the outside than the inner surface, and it is possible to avoid the display element and the like being arranged close to the face and easily causing interference, and the degree of freedom in the arrangement and size of the projection optical components is improved.

[0099] In a virtual image display device of a specific embodiment, the polarization separation film reflects s-polarized image light and transmits image light that is reflected by a transmissive mirror and returns through a quarter-wave plate to become p-polarized light.

[0100] In a specific embodiment of the virtual image display device, the second lens is formed by an adhesive that joins the compensation lens and the quarter wavelength plate. In this case, even if the second lens is thin, the second lens can be easily formed.

[0101] In a specific embodiment of the virtual image display device, the second lens is formed by a liquid filled in a filling space between the compensation lens and the 1 / 4 wavelength plate. In this case, even if the second lens is thin, the second lens can be easily formed. By making the material of the second lens a liquid having a refractive index equal to that of the compensation lens, it is effective when the refractive index equal to that of the compensation lens cannot be obtained by using an adhesive. In addition, by using a liquid for the second lens, there is no need to consider the curing shrinkage of the adhesive, etc.

[0102] In a specific embodiment of the virtual image display device, the liquid is a liquid refractive index adjustment member filled between the compensation lens and the quarter wavelength plate and sealed around with an adhesive.

[0103] The optical unit in the specific embodiment is a direct virtual image type optical unit, which comprises: a first lens having a positive refractive power, on which image light from a display element emitting image light is incident; a first prism, on which image light passing through the first lens is incident; a second prism, which is joined to the first prism to form a parallel flat plate-shaped prism light guide component; a planar polarization separation film, which is arranged at the junction of the first prism and the second prism, and selectively reflects the image light guided in the first prism according to the polarization direction; an angle selection film, which is arranged in the prism light guide component and reflects the image light guided in the first prism and The outer side surface on which the image light reflected by the polarization separation film is incident shows different separation characteristics depending on the incident angle of the image light; a plano-convex second lens having a plane arranged opposite to the angle selection film; a transmissive reflector formed on the convex surface of the second lens, which partially reflects the image light reflected by the polarization separation film toward the polarization separation film; a 1 / 4 wavelength plate arranged between the angle selection film and the plane of the second lens; and a compensation lens having a concave surface and a plane parallel to the outer side surface of the first prism, the concave surface having a shape obtained by inverting the convex surface of the second lens, and being joined to the convex surface via the transmissive reflector.

Claims

1. A direct virtual image type virtual image display device, comprising: A display element that emits image light; a first lens having a positive refractive power, the image light from the display element being incident on the first lens; a first prism on which the image light having passed through the first lens is incident; A second prism joined to the first prism to form a parallel flat plate-shaped prism light guide component; A planar polarization separation film, which is disposed at a junction between the first prism and the second prism, and selectively reflects the image light guided in the first prism according to a polarization direction; An angle selection film disposed on an outer side surface of the prism light guide component on which the image light guided in the first prism and reflected by the polarization separation film is incident, and exhibits different separation characteristics according to the incident angle of the image light; a plano-convex second lens having a flat surface, wherein the flat surface is arranged opposite to the angle selective film; a transmissive reflector disposed on the convex surface of the second lens and reflecting part of the image light reflected by the polarization separation film toward the polarization separation film; a quarter wavelength plate disposed between the angle selection film and the plane of the second lens; and The compensating lens has a concave surface and a flat surface parallel to the outer side surface of the prism light guide member, wherein the concave surface has a shape obtained by reversing the convex surface of the second lens and is bonded to the convex surface via the transmissive reflector.

2. The virtual image display device according to claim 1, wherein: The first lens, the prism light guide member, the polarization separation film, the angle selection film, the second lens, the transmissive reflector, and the quarter-wave plate constitute a single-microscope type imaging optical system that forms an erect image. The first prism diverges the image light and causes it to be internally reflected twice.

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

4. The virtual image display device according to claim 1, wherein: The virtual image display device further includes a compensation plate, which is disposed around the compensation lens and extends parallel to the prism light guide component.

5. The virtual image display device according to claim 1, wherein: The angle selection film is bonded to the quarter wavelength plate.

6. The virtual image display device according to claim 1, wherein: The first lens has a planar light incident surface and a convex light emitting surface, and the planar light incident surface is bonded to the display element.

7. The virtual image display device according to claim 1, wherein: The first prism has an incident optical surface, and the incident optical surface has positive refractive power. The incident optical surface has an optical axis extending in a direction less than 90° with respect to a normal line of the inner side surface.

8. The virtual image display device according to claim 1, wherein: The polarization separation film reflects the image light of s-polarized light, and transmits the image light that is reflected by the transmissive reflector and returns through the quarter-wave plate to become p-polarized light.

9. The virtual image display device according to claim 1, wherein: The second lens is formed by an adhesive bonding the compensation lens and the quarter wavelength plate.

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

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

12. A direct virtual image optical unit comprising: a first lens having positive refractive power, and image light from a display element emitting image light is incident on the first lens; a first prism on which the image light having passed through the first lens is incident; A second prism joined to the first prism to form a parallel flat plate-shaped prism light guide component; A planar polarization separation film, which is disposed at a junction between the first prism and the second prism, and selectively reflects the image light guided in the first prism according to a polarization direction; An angle selection film disposed on an outer side surface of the prism light guide component on which the image light guided in the first prism and reflected by the polarization separation film is incident, and exhibits different separation characteristics according to the incident angle of the image light; a plano-convex second lens having a flat surface, wherein the flat surface is arranged opposite to the angle selective film; a transmissive reflector disposed on the convex surface of the second lens and reflecting part of the image light reflected by the polarization separation film toward the polarization separation film; a quarter wavelength plate disposed between the angle selection film and the plane of the second lens; and The compensating lens has a concave surface and a flat surface parallel to the outer side surface of the prism light guide member, wherein the concave surface has a shape obtained by reversing the convex surface of the second lens and is bonded to the convex surface via the transmissive reflector.

Images