Virtual image display device and optical unit

Abstract

A virtual image display device and an optical unit prevent brightness of an optical system from decreasing. A virtual image display device includes: a display element; a first lens; a first prism and a second prism that are joined to each other to form a parallel plate-shaped prism light guide member; an inclined mirror part which is provided at the junction of the first prism and the second prism and reflects a first portion of the image light; a plano-convex second lens disposed so as to face the outer surface of the first prism; a transmission mirror which is formed on the convex surface of the second lens and reflects a part of the image light reflected by the inclined mirror part to the inclined mirror part; a first 1 / 4 wavelength plate disposed between the first prism and the second lens; a compensation lens having a concave surface joined to the convex surface of the second lens via a transmission mirror and a plane parallel to the outer surface; a condenser mirror that reflects a second portion of the image light reflected by the inner surface of the second prism through the inclined mirror portion; and a second 1 / 4 wavelength plate disposed between the inner surface and the condenser mirror.

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, and is partially reflected by the semi-transmitting reflection surface formed at the boundary between the first prism and the second prism of the prism component, then 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 then 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 above-mentioned head mounted display, since two reflective members are present in front of the eye, the brightness of the image light reaching the exit pupil is lower than that of an object in which the total number of reflective members is one surface. Summary of the invention

[0005] The virtual image display device of one aspect of the present invention is a direct virtual image type virtual image display device, which comprises: a display element emitting image light; a first lens, on which the image light from the display element is incident; a first prism, on 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-guiding component; an inclined reflector portion, which is provided at the junction of the first prism and the second prism and reflects a first portion of the image light guided in the first prism; and a plano-convex second lens, which is arranged opposite to the outer side surface of the first prism on which the first portion of the image light reflected by the inclined reflector portion is incident. ; a transmission reflector formed on the convex surface of the second lens, reflecting a portion of the image light reflected by the inclined reflector portion toward the inclined reflector portion; a first 1 / 4 wavelength plate, arranged between the outer side surface of the first prism and the second lens; a compensation lens, having a concave surface joined to the convex surface of the second lens via the transmission reflector and a surface parallel to the outer side surface of the first prism; a focusing reflector, arranged in the second prism, reflecting a second portion of the image light that passes through the inclined reflector portion and is reflected by the inner side surface of the second prism; and a second 1 / 4 wavelength plate, arranged between the inner side surface of the second prism and the focusing 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, on which the 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, which is joined to the first prism to form a parallel flat plate-shaped prism light-guiding component; an inclined reflector portion, which is provided at a junction between the first prism and the second prism, and reflects a first portion of the image light guided in the first prism; a plano-convex second lens, which is arranged opposite to the outer side surface of the first prism on which the first portion of the image light reflected by the inclined reflector portion is incident; and a transverse mirror portion. a transmission reflector formed on the convex surface of the second lens, reflecting a portion of the image light reflected by the inclined reflector portion toward the inclined reflector portion; a first 1 / 4 wavelength plate arranged between the outer side surface of the first prism and the second lens; a compensation lens having a concave surface joined to the convex surface of the second lens via the transmission reflector and a surface parallel to the outer side surface of the first prism; a focusing reflector arranged in the second prism, reflecting a second portion of the image light that passes through the inclined reflector portion and is reflected by the inner side surface of the second prism; and a second 1 / 4 wavelength plate arranged between the inner side surface of the second prism and the focusing reflector. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 This is an external view for explaining the use 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 This is a conceptual perspective view for explaining the first display unit.

[0010] Figure 4 It is a perspective view for explaining the appearance structure of the first display unit.

[0011] Figure 5 This is a diagram for explaining the shapes of the first image forming element and the first lens, etc.

[0012] Figure 6 It is a side cross-sectional view for explaining the optical path inside the display device on one side.

[0013] Figure 7 This is a side cross-sectional view for explaining how image light emitted from a specific area of ​​a display element enters an exit pupil in a one-sided display device.

[0014] Figure 8This is a side cross-sectional view for explaining how image light emitted from a specific area of ​​a display element enters an exit pupil in a one-sided display device.

[0015] Fig. 9 This is a side cross-sectional view for explaining how image light emitted from a specific area of ​​a display element enters an exit pupil in a one-sided display device.

[0016] Fig.10 Yes Figure 7 , Figure 8 as well as Fig. 9 Overlapped graph.

[0017] Fig.11 Is the description and Fig.10 A diagram showing the results of a computer simulation of the angles of light rays for a portion of an image.

[0018] Fig.12 It is a diagram for explaining the estimation of the utilization efficiency of image light and the perspective transmittance in the first embodiment.

[0019] Fig.13 This is a diagram for explaining an example of the structure of a prism light guide component.

[0020] Fig.14 This is a diagram for explaining an example of assembling a prism light guide component.

[0021] Fig.15 This is a perspective view for explaining an example of the structure and assembly of the first display unit.

[0022] Fig.16 It is a side cross-sectional view for explaining the internal structure of one side of the display device according to the second embodiment.

[0023] Fig.17 It is a side cross-sectional view for explaining another internal structure of the one-sided display device according to the second embodiment.

[0024] Fig.18 It is a diagram showing an example of the optical path of stray light.

[0025] Fig.19 It is a diagram showing the observation direction of the focusing reflector.

[0026] Fig. 20 This is a diagram for explaining a structure in which a focusing reflector is divided into a plurality of partial reflective surfaces.

[0027] Fig.21 It is a side cross-sectional view showing the structure of the second lens composed of a plurality of materials.

[0028] Fig. 22 It is a side cross-sectional view showing a difference in the path of light incident on the second lens.

[0029] Description of symbols

[0030] 11: display element; 20a, 20b: display unit; 30: first lens; 30f: light incident surface; 30g: light exit surface; 31: parallel plate; 32: lens unit; 40: first flat plate-shaped member; 41b, 42b: inner side surface; 41c, 42c: outer side surface; 41d, 42d: inclined surface; 44: third lens; 45: inclined reflector unit; 45A: polarization separation film; 45B: half mirror; 45C: polarization separation film; 48: prism light guide member; 50: second flat plate-shaped member; 50c: inner side surface; 51: 1 / 4 wavelength plate; 52: cover member; 53f: plane surface; 53g: convex surface; 54: compensation lens; 54f: concave surface; 5 4g, 55f, 55g: plane; 55: compensation plate; 56: transmission reflector; 58: optical element; 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; AX: optical axis; CR1, CR2: focusing reflection unit; CT: adhesive; DIS: direct virtual image optical system; EP: exit pupil; EY: eye; IS: imaging optical system; ML: image light; OL: external light; PP: pupil position; SS: joint; US: wearer. DETAILED DESCRIPTION

[0031] First embodiment

[0032] Below, refer to Figure 1 , Figure 2 etc., a first embodiment of the virtual image display device etc. of the present invention is described.

[0033] 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.

[0034] 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 side 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.

[0035] Figure 2 1 is a side 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 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 includes a third lens 44 that is opposite to the first lens 30. The first flat plate-shaped member 40 guides the image light ML emitted from the display element 11 and incident from the third lens 44 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 third lens 44, the first flat member 40, and the second flat member 50 each function as a lens having a positive refractive power.

[0036] 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.

[0037] 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 image light ML to the first flat plate-shaped component 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 component 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 an LCD, 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 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 be said to be a part equivalent to the direct virtual image optical system DIS constituting the first virtual image display device 100A.

[0038] The first display unit 20a includes a first lens 30, a first flat plate-shaped member 40, a polarization separation film 45A as a tilted reflector portion 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 axially symmetrical 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 not easily 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.

[0039] The first flat-plate-shaped component 40 has a third lens 44 which is a plano-convex lens, a first prism 41 which is a parallel flat-plate-shaped, and a second prism 42 which is a parallel flat-plate-shaped. The third lens 44 and the first prism 41 are joined by inclined surfaces 44b and 41a. The first prism 41 and the second prism 42 are joined by inclined surfaces 41d and 42d. The component formed by joining the third lens 44, the first prism 41 and the second prism 42 is called a prism light-guiding component 48. The prism light-guiding component 48 has the appearance of a parallel flat plate. On the inclined surface 41d formed on the lower side of the first prism 41, a polarization separation film 45A which is an inclined reflector portion 45 which is a plane is formed. The component formed by combining the prism light-guiding component 48 and the second flat-plate-shaped component 50 which will be described later is equivalent to Figure 1 The first combiner 103a.

[0040] The third lens 44 is a plano-convex lens having a positive refractive index, and has an incident optical surface 44a opposite to the light exit surface 30g of the first lens 30 and an inclined surface 44b coupled to the first prism 41. The incident optical surface 44a is a convex surface, for example, a spherical surface, but can be set as an axisymmetric aspherical surface. The third lens 44 is made of, for example, fused quartz and has a low refractive index. The third lens 44 has a refractive index equivalent to that of the first lens 30.

[0041] The first prism 41 has a quadrangular prism shape and a trapezoidal longitudinal section. The first prism 41 guides the image light ML and has an inclined surface 41a combined with the inclined surface 44b of the third lens 44, an inner side surface 41b, an outer side surface 41c, and an inclined surface 41d. In addition, the first prism 41 has an upper plane 40u and a part of a horizontal plane 40v described later (see Figure 3 etc.). Here, the inclined surface 41a is tilted downward in the front direction as a whole, and the optical axis passing through the inclined surface 41a extends in the direction between the front, i.e., the +Z direction, and the upper, i.e., the +Y direction. Thus, it is easy to arrange the first image forming element 11a as the display element 11 at a position closer to the outside than the inner surface 41b, and it is possible to adjust the angle of the image light ML propagating in the first prism 41 (in the first prism 41 or inside the first prism 41). The inner surface 41b and the outer surface 41c are parallel to each other and extend perpendicularly to the optical axis AX between the pupil position PP. The inner surface 41b and the outer surface 41c reflect the image light ML internally (i.e., reflect it on the inner side of the object surface), but it is particularly preferred to perform total reflection. The scratch resistance or abrasion resistance of the inner surface 41b can be improved by applying a hard coating. The inclined surface 41d is a plane. The inclined surface 41d forms an acute angle with respect to the outer surface 41c, specifically, an angle of 25° to 32°. The distance between the optical axis AX passing through the pupil position PP and the first lens 30 is about 20 mm. The first prism 41 is formed of a glass or resin material and has a higher refractive index than that of the first lens 30 .

[0042] The number of reflections of the image light ML in the first prism 41 is basically once at the inner side surface 41b, once at the outer side surface 41c, and further once at the polarization separation film 45A described later. By setting the number of internal reflections of the image light ML in the first prism 41 to 2 times, the viewing angle, pupil position PP or its opening PPa of the image light ML can be increased, and the mixing of light with 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 divergent state, and the divergence state is maintained. Here, the divergence state of the image light ML refers to a state in which the area of ​​the image light ML occupying an arbitrary imaginary plane orthogonal to the optical axis gradually expands as the image light ML moves along the optical axis. Furthermore, the divergence of the image light ML is suppressed to at least such an extent that the image light ML converges inside the first prism 41 including before and after reflection of the image light ML on the inner surface 41 b and the outer surface 41 c in any virtual plane orthogonal to the optical axis.

[0043] The second prism 42 has a quadrangular prism shape and a trapezoidal longitudinal section similar to the first prism 41. The second prism 42 transmits the image light ML and has an inner side surface 42b, an outer side surface 42c, and an inclined surface 42d. In addition, the second prism 42 has a part of the later-described horizontal plane 40v and a lower plane 40w (see Figure 3 , Figure 4 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, the scratch resistance or abrasion resistance can be improved by applying a hard coating. The second prism 42 is formed of a glass or resin material and has a refractive index equal to that of the first prism 41.

[0044] The polarization separation film 45A 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 polarization separation film 45A and the inclined surface 42d are filled with an adhesive CT for bonding. The polarization separation film 45A 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 45A only needs to selectively reflect the image light ML according to the polarization direction, for example, it can also be a wire grid. The polarization separation film 45A only needs to be a flat surface that does not affect the imaging. In addition, the polarization separation film 45A can also have a convex or concave micro-curved surface that does not affect the imaging. The polarization separation film 45A 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 45A and the inclined surface 41d instead of the adhesive CT. In this case, the first prism 41 and the second prism 42 may also be supported from the outside by a supporting member or the like to maintain the joined state. In addition, the polarization separation film 45A may also be integrally formed on the inclined surface 42d of the second prism 42 instead of being formed on the inclined surface 41d of the first prism 41.

[0045] When the reflection angle of the image light ML on the optical axis AX in the first prism 41 is β0, the inclination angle θ of the polarization separation film 45A is greater than 90°-β0. As a premise that the polarization separation film 45A does not hinder the path of the image light ML, when the maximum reflection angle of the image light ML is βmax, the inclination angle θ of the polarization separation film 45A 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 surface 41b and the optical axis AX passing through the incident optical surface 44a, which is an acute angle. That is, the optical axis AX of the incident optical surface 44a extends in a direction less than 90° relative to the normal line of the inner surface 41b.

[0046] 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 45A 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 extending parallel to the prism light guide member 48, and a transmission reflector 56.

[0047] The second flat plate-shaped member 50 is arranged to be separated from the first flat plate-shaped member 40 by about 20 μm to 50 μm. The outer side surfaces 41c and 42c of the first flat plate-shaped member 40 and the inner side surface 50c of the second flat plate-shaped member 50 may be slightly curved, and a small step may be formed at the boundary between the outer side surfaces 41c and 42c. However, by making the interval between the outer side surfaces 41c and 42c and the inner side surface 50c 20 μm or more, more preferably 30 μm or more, it is possible to avoid these surfaces from being too close. On the contrary, by making the interval between the outer side surfaces 41c and 42c and the inner side surface 50c 50 μm or less, it is possible to avoid the thickness of the first combiner 103a formed by combining the first flat plate-shaped member 40 and the second flat plate-shaped member 50 to increase. A spacer 61 is provided between the outer side surfaces 41c and 42c of the first flat plate-shaped member 40 and the inner side surface 50c of the second flat plate-shaped member 50, and the spacer 61 is used to fix the first flat plate-shaped member 40 and the second flat plate-shaped member 50 in a state where they are positioned to each other by adjusting the interval between them. The spacer 61 is not provided over the entire circumference of the second flat-plate-shaped member 50. That is, the gap SP between the first flat-plate-shaped member 40 and the second flat-plate-shaped member 50 is not sealed but communicates with the outside.

[0048] 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 opposite to 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 opposite to 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 transmission 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 formed by combining the second lens 53 and the transmission reflector 56 is called the first focusing reflection part CR1.

[0049] The second lens 53, 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.

[0050] 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. Therefore, the compensation lens 54 optically compensates for the influence of the second lens 53 on the external light OL. In this sense, the plane 53f of the second lens 53, the plane 54g of the compensation lens 54, and the planes 55f and 55g of the compensation plate 55 are not limited to strict planes, for example, they can be roughly flat, or they can include curved surfaces partially or entirely. In addition, the plane 53f of the second lens 53, the plane 54g of the compensation lens 54, and the planes 55f and 55g of the compensation plate 55 can also include curved surfaces for correcting the vision of the wearer US, or curved surfaces as designed such as sunglasses or plain glasses within the range that does not cause poor optical performance. The planes 54g and 55g of the compensation lens 54 and the compensation plate 55 can be coated 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 the compensation plate 55 from the peripheral area outside the incident area of ​​the image light ML corresponding to the compensation lens 54. Thus, 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.

[0051] 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°.

[0052] The transmission reflector 56 is a half mirror that reflects a part of the image light ML that has passed through the second lens 53 and transmits a part of the external light OL. The transmission reflector 56 reflects the image light ML that has been reflected by the polarization separation film 45A of the first flat member 40 and has passed through the 1 / 4 wavelength plate 51 and the second lens 53 toward the pupil position PP. The transmission 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, which corresponds to the exit pupil EP of the first display unit 20a.

[0053] The transmission reflector 56 transmits a part of the external light OL, so that the external world can be observed through 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 perspective of ensuring the brightness of the image light ML and making it easy to observe the external image through perspective, the reflectivity of the transmission 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 transmission 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 transmission 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 transmission reflector 56 is formed, for example, by stacking using vapor deposition.

[0054] Figure 3 2 is a conceptual perspective view mainly illustrating the first display unit 20a. Figure 3 In FIG. 1 , area AR1 represents a state where the first display unit 20a is viewed obliquely upward from between +Z in the front and +X in the side, and area AR2 represents a state where the first display unit 20a is viewed from the +Z side in the front. Figure 3 In the figure, the transmission reflector 56 in the second flat plate-shaped member 50 is omitted, and only the second lens 53 is shown.

[0055] In the first virtual image display device 100A, the first lens 30, the third lens 44, the second lens 53 and the transmission reflector 56 each have a positive refractive power and have a tendency to converge divergent light. The first lens 30, the third lens 44, the second lens 53 and the transmission 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 forward. At this time, by adjusting the refractive power of the first lens 30, the third lens 44, the second lens 53 and the transmission reflector 56, the focal length of the imaging optical system IS can be shortened to achieve the desired magnification.

[0056] like Figure 2As shown, the following optical path is referred to as the first optical path P1: after a part of the image light ML is emitted from the display element 11, it is reflected twice by the inner side surface 41b and the outer side surface 41c of the first prism 41, reflected by the polarization separation film 45A as the inclined reflector portion 45, passes through the first 1 / 4 wavelength plate 51 and the second lens 53, is reflected by the transmission reflector 56, passes through the second lens 53 and the first 1 / 4 wavelength plate 51 again, passes through the polarization separation film 45A and travels to the exit pupil EP. In addition, the part of the image light ML having a predetermined polarization is sometimes referred to as the polarization component of the image light ML or simply as a component.

[0057] like Figure 2 and Figure 3 As shown, a second light-collecting reflective portion CR2 is provided in the prism light-guiding component 48. The second light-collecting reflective portion CR2 includes a second 1 / 4 wavelength plate 21 and a light-collecting reflective mirror 24. By providing the light-collecting reflective portion CR2 in the prism light-guiding component 48, a portion of the image light ML generated by the display element 11 that is not reflected by the polarization separation film 45A but passes through the polarization separation film 45A can be collimated and emitted to the exit pupil side. Thus, even if two reflective components including the polarization separation film 45A and the transmission reflective mirror 56 are present in front of the eye, the utilization efficiency of the image light generated by the display element 11 can be improved, thereby improving the brightness of the image light ML.

[0058] like Figure 2 As shown, the following optical path is called the second optical path P2: after a portion of the image light ML is emitted from the display element 11, it is reflected twice by the inner side surface 41b and the outer side surface 41c of the first prism 41, passes through the polarization separation film 45A which is the inclined reflector portion 45, is reflected by the inner side surface 42b of the second prism 42, passes through the second 1 / 4 wavelength plate 21, is reflected by the focusing reflector 24, is reflected again by the inner side surface 42b of the second prism 42, is reflected by the polarization separation film 45A, and travels to the exit pupil EP.

[0059] Reference Figure 4 , the longitudinal dimension ay of the first flat plate-shaped component 40 or the second flat plate-shaped component 50 is, for example, 34 mm, and its lateral dimension ax is, for example, 40 mm. The thickness az of the first flat plate-shaped component 40 in the front-to-back direction is, for example, about 7 mm, and the total thickness of the first flat plate-shaped component 40 and the second flat plate-shaped component 50 is suppressed to about 7.5 mm. In the first flat plate-shaped component 40, an upper plane 40u is provided on the left and right of the incident optical surface 44a. Light is not allowed to be incident on the upper plane 40u. From the viewpoint of preventing stray light, a light-shielding body (not shown) that is opposite to the upper plane 40u and covers it can be arranged on the upper plane 40u, or a light-shielding body can be applied. A light-shielding body that covers the horizontal plane 40v and the lower plane 40w can also be provided. A light-shielding body that covers the second flat plate-shaped component 50 can also be provided around it.

[0060] Reference Figure 5 , the shapes of the first image forming element 11a and the first lens 30 are described. Figure 5 In the figure, region BR1 represents the state of observing the first lens 30 etc. from the front +Z side in an obliquely upward direction, region BR2 represents the state of observing the first lens 30 etc. from the bottom -Y side in an obliquely forward direction, and region BR3 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.

[0061] The curvature radius of the convex light exit surface 30g of the first lens 30 is, for example, 20 mm. Figure 2 The radius of curvature of the incident optical surface 44 a of the illustrated first prism 41 is, for example, 14 mm, and the radius of curvature of the transmission reflector 56 is, for example, 47 mm.

[0062] Reference Figure 2 , the first optical path P1 not affected by the focusing reflection part CR2 is described in detail, and the image light ML from the first image forming element 11a is incident on the first prism 41 via the first lens 30 and the third lens 44. At this time, the image light ML is suppressed from diverging due to the positive refractive power of the first lens 30 and the third lens 44. In the optical path passing through the first prism 41, the image light ML does not form an intermediate image, but 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-polarized light s component in the image light ML is reflected by the polarization separation film 45A. The image light ML of the s-polarized light s reflected by the polarization separation film 45A passes through the outer side surface 41c of the first prism 41, passes through the first 1 / 4 wavelength plate 51 included in the second flat plate-shaped member 50, and thus becomes circularly polarized light c, and is incident on the transmission reflection mirror 56. Part of the image light ML of the circularly polarized light c incident on the transmission reflector 56 is reflected by the transmission reflector 56 via the second lens 53, and passes through the first quarter wavelength plate 51 again in a state of being collimated by the second lens 53. As a result, the image light ML that has passed through the first quarter wavelength plate 51 becomes p-polarized light p and is incident on the first prism 41 from the outer side surface 41c, passes through the polarization separation film 45A, 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 transmission reflector 56 but also the external light OL that has passed through the transmission 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.

[0063] Reference Figure 2 as well as Figure 3 Next, the condensing and reflecting portion CR2 will be described. As described above, the condensing and reflecting portion CR2 includes the second quarter wavelength plate 21 and the condensing and reflecting mirror 24 .

[0064] The second quarter wavelength plate 21, like the first quarter wavelength plate 51, converts the image light ML of s-polarized light s (or p-polarized light p) that is transmitted through the polarization separation film 45A and reflected by the inner surface 42b of the second prism 42 into circularly polarized light c, and converts the image light ML of circularly polarized light c that is reflected by the focusing reflector 24 into p-polarized light p (or s-polarized light s).

[0065] The condensing reflector 24 reflects the image light ML that has passed through the quarter-wave plate 21 and is directed toward the condensing reflector 24 toward the quarter-wave plate 21 while condensing it on a concave surface 24 a that is a reflection surface of the condensing reflector 24 .

[0066] The focusing reflector 24 is arranged in the prism light guide component 48 so that the length of the first optical path P1 from which the image light ML is emitted from the display element 11 and travels through the transmission reflector 56 outside the prism light guide component 48 to reach the eye EY is approximately the same as the length of the second optical path P2 from which the image light ML is emitted from the display element 11 and travels through the focusing reflector 24 in the prism light guide component 48 to reach the eye EY. Here, the approximately same lengths of the first optical path P1 and the second optical path P2 are one of the conditions for observing the positions and sizes of each pixel of the image light ML at the exit pupil EP to be consistent in the first component traveling along the first optical path P1 and the second component traveling along the second optical path P2 in the image light ML reaching the exit pupil EP. As long as this condition is met, the lengths of the first optical path P1 and the second optical path P2 do not have to be the same. Hereinafter, the length of the first optical path P1 is sometimes referred to as the first optical path length, and the length of the second optical path P2 is sometimes referred to as the second optical path length.

[0067] Moreover, the curvature of the condensing reflector 24 is substantially the same as the curvature of the transmission reflector 56. In addition, the material of the second lens 53 is substantially the same as the material of the second prism 42. However, these curvatures and raw materials do not have to be the same as long as the position and size of each pixel of the image light ML at the exit pupil EP are observed to be consistent. As a result, the image light ML passing through the first optical path P1 and the image light ML passing through the second optical path P2 are in an overlapping state when observed from the eye EY of the wearer US. At this time, compared with the brightness when only the image light ML passing through the first optical path P1 is observed, the brightness of the image light ML is increased by an amount corresponding to the image light ML passing through the second optical path P2.

[0068] Reference Figure 6 , the first optical path P1 and the second optical path P2 are described in detail. Figure 6 In order to make it easier to distinguish the optical paths P1 and P2, the shapes and sizes of the components are schematically shown. Figure 6 In FIG. 1 , the length L1 of the first optical path P1 is schematically indicated by a dotted arrow, and the length L2 of the second optical path P2 is schematically indicated by a dashed arrow.

[0069] As described above, the first optical path P1 is the following optical path: after the image light ML is emitted from the display element 11 as light La1, it is reflected a total of two times on the inner side surface 41b and the outer side surface 41c of the prism light guide component 48, and a part of the light La1 is reflected by the polarization separation film 45A as light Lb2, passes through the first 1 / 4 wavelength plate 51 and the second lens 53, is reflected by the transmission reflector 56, passes through the second lens 53 and the first 1 / 4 wavelength plate 51 again as light Lb3, passes through the polarization separation film 45A, and is emitted from the inner side surface 42b of the prism light guide component 48 as light Lb4 to reach the eye EY.

[0070] In addition, the second optical path P2 is the following optical path: after the image light ML is emitted from the display element 11 as light La1, it is reflected a total of two times on the inner side surface 41b and the outer side surface 41c of the prism light guide component 48, and a part of the light La1 passes through the polarization separation film 45A as light Lc2, is reflected by the inner side surface 42b of the prism light guide component 48, passes through the second 1 / 4 wavelength plate 21, is reflected by the focusing reflector 24, passes through the second 1 / 4 wavelength plate 21 again as light Lc3, is reflected again by the inner side surface 42b of the prism light guide component 48, is reflected by the polarization separation film 45A, and is emitted from the inner side surface 42b of the prism light guide component 48 as light Lc4 to reach the eye EY.

[0071] Reference Figure 7 , Figure 8 , Fig. 9 and Fig.10 , the result of confirming, by computer simulation, that a part of the image light ML emitted from the display element 11 enters the exit pupil EP will be described. Figure 7 The first image light MLA emitted from the first display region 11A of the display element 11 and the first partial image light MLa included in the first image light MLA are shown. Figure 6 The first light path P1 and the second light path P2 shown in the figure respectively reach the exit pupil EP as parallel light. Figure 8 The second image light MLB emitted from the second display region 11B of the display element 11 and the second partial image light MLb included in the second image light MLB are shown. Figure 6The first light path P1 and the second light path P2 shown in the figure respectively reach the exit pupil EP as parallel light. Fig. 9 The third image light MLC emitted from the third display region 11C of the display element 11 and the third partial image light MLC included in the third image light MLC are shown as follows: Figure 6 The first light path P1 and the second light path P2 shown in the figure respectively reach the exit pupil EP as parallel light. Fig.10 Overlapping Figure 7 , Figure 8 as well as Fig. 9 The first image light MLA, the first partial image light MLa, the second image light MLB, the second partial image light MLb, the third image light MLC and the third partial image light MLc are shown.

[0072] exist Figure 7 , Figure 8 , Fig. 9 and Fig.10 In the example shown, the second partial image light MLb emitted from the second display area 11B which is the central area of ​​the display element 11 passes through the central part of the emission pupil EP, and the first partial image light MLa and the third partial image light MLc emitted from the first display area 11A and the third display area 11C which are the peripheral areas of the display element 11 respectively pass through the portion deviated from the central part of the emission pupil EP.

[0073] Reference Fig.11 , the exit pupil EP is confirmed by computer simulation Fig.10 The results of the light angles when the first partial image light MLa, the second partial image light MLb, and the third partial image light MLc arrive at the display element 11 are described. Region DR1 shows the distribution of the brightness of the image light observed at the exit pupil EP in logarithmic angles, and region DR2 shows an enlarged view of the central portion DR10 in region DR1. When the display element 11 emits only the first partial image light MLa, the second partial image light MLb, and the third partial image light MLc, the light is incident only on Fig.11 Thus, it is confirmed that the first partial image light MLa, the second partial image light MLb, and the third partial image light MLc are parallel to the first image light MLA, the second image light MLB, and the third image light MLC passing through the transmission reflector 56 disposed in front of the eye.

[0074] Furthermore, all of the partial image lights MLa, MLb, and MLc can be made to pass through the center of the exit pupil EP by making the prism light guide member 48 thicker or making the condensing reflector 24 larger without changing the thickness of the prism light guide member 48 .

[0075] Reference Fig.12 , a comparison between the present embodiment and two comparative examples regarding the utilization efficiency and the see-through transmittance of the image light ML emitted from the display element 11 will be described. Fig.12 An example of the results of trial calculations of the utilization efficiency and the perspective transmittance of the image light ML in this embodiment is shown. Fig.12 In order to make it easier to distinguish each optical path, the shape and size of each component are schematically shown.

[0076] exist Fig.12 In the display units 20a and 20b of the present embodiment shown, the brightness of the image light ML at the time of being emitted by the display element 11 is assumed to be 100%. The image light ML emitted by the display element 11 is reflected twice by the inner side surface 41b and the outer side surface 41c of the first prism 41 as light La1 containing the s-polarized light s component and the p-polarized light p component, and then travels toward the polarization separation film 45A. The s-polarized light s component in the light La1 travels along the first optical path P1, is reflected by the polarization separation film 45A, and travels toward the 1 / 4 wavelength plate 51 as light Lb2. Here, the brightness of the light Lb2 is 50% of the brightness of the light La1 immediately before being separated by the polarization separation film 45A, and is 50% of the brightness of the image light ML at the time of being emitted. When the light Lb2 passes through the 1 / 4 wavelength plate 51, it travels toward the second lens 53 as light Lb3 whose polarization is changed from the s-polarized light s to the right-handed circularly polarized light c. Next, the light Lb3 is reflected by the transmission mirror 56 and travels toward the 1 / 4 wavelength plate 51 as the light Lb4. Here, when the transmittance and reflectance of the transmission mirror 56 are 50%, the brightness of the light Lb4 is 50% of the brightness of the light Lb3 just before being reflected by the transmission mirror 56, and is 25% of the brightness of the image light ML at the time of emission. In addition, the right-handed circularly polarized light c of the light Lb3 is reflected by the transmission mirror 56, thereby becoming the left-handed circularly polarized light c of the light Lb4. And, when the light Lb4 passes through the 1 / 4 wavelength plate 51 again, it travels toward the polarization separation film 45A as the light Lb5 whose polarization is changed from the left-handed circularly polarized light c to the p-polarized light p. Next, the light Lb5 passes through the polarization separation film 45A and travels toward the emission pupil EP as the light Lb6. Here, the brightness of the light Lb6 is the same as the brightness of the light Lb5 just before passing through the polarization separation film 45A, and is 25% of the brightness of the image light ML at the time of emission.

[0077] also, Fig.12The p-polarized light p component in the light La1 shown travels in the second optical path P2, passes through the polarization separation film 45A, and is reflected by the inner side surface 42b of the second prism 42 as light Lc2 and heads toward the quarter wavelength plate 21. Here, the brightness of the light Lc2 is 50% of the brightness of the light La1 immediately before being separated by the polarization separation film 45A, and is 50% of the brightness of the image light ML at the time of emission. When the light Lc2 passes through the quarter wavelength plate 21, the polarization changes from the p-polarized light p to the right-handed circularly polarized light c, and heads toward the condensing reflector 24. And, when the light Lc3 is reflected by the condensing reflector 24, the polarization changes from the right-handed circularly polarized light c to the left-handed circularly polarized light c, and heads toward the quarter wavelength plate 21. When the light Lc4 passes through the 1 / 4 wavelength plate 21 again, the light Lc5 whose polarization is changed from the right-handed circularly polarized light c to the s-polarized light s is reflected by the inner side surface 42b of the second prism 42 and is directed toward the polarization separation film 45A. Here, the brightness of the light Lc5 is the same as the brightness of the light Lc2, which is 50% of the brightness of the image light ML at the time of emission. Then, the light Lc5 is reflected by the polarization separation film 45A and is directed toward the emission pupil EP as the light Lc6. Here, the brightness of the light Lc6 is the same as the brightness of the light Lc5 reflected by the polarization separation film 45A, which is 50% of the brightness of the image light ML at the time of emission.

[0078] And, if Fig.12 As shown, the external light OL is incident on the second lens 53 from the transmission reflector 56 as the light Le1. It is assumed that the brightness of the external light OL immediately before being incident on the transmission reflector 56 is 100%. However, the brightness of the image light ML at the time of emission is not necessarily the same as the brightness of the external light OL immediately before being incident. The light Le1 passes through the transmission reflector 56 and is directed toward the 1 / 4 wavelength plate 51 as the light Le2. Here, when the transmittance of the transmission reflector 56 is 50%, the brightness of the light Le2 is 50% of the brightness of the external light OL immediately before being incident. The light Le1 and the light Le2 contain a left-handed circularly polarized light c component and a right-handed circularly polarized light c component. When the light Le2 passes through the 1 / 4 wavelength plate 51, it is incident on the second prism 42 from the outer side surface 42c as the light Le3 and is directed toward the polarization separation film 45A. The left-handed circularly polarized light c component and the right-handed circularly polarized light c component of the light Le2 are respectively converted into the s-polarized light s component and the p-polarized light p component of the light Le3 by passing through the 1 / 4 wavelength plate 51. The p-polarized light p component in the light Le3 passes through the polarization separation film 45A and is directed toward the exit pupil EP as the light Le4. Here, the brightness of the light Le4 is 50% of the brightness of the light Le3 immediately before passing through the polarization separation film 45A, and is 25% of the brightness of the external light OL immediately before being incident.

[0079] According to the above estimates, Fig.12Among the lights reaching the exit pupil EP, the total brightness of light Lb6 and light Lc6 originating from the image light ML is 75% of the brightness of the image light ML at the time of emission, and the brightness of light Le4 originating from the external light OL is 25% of the brightness of the external light OL just before incidence.

[0080] The display unit 120 of the first comparative example corresponds to Fig.12 The display units 20a and 20b of the present embodiment shown in the figure are modified as follows: That is, the second quarter-wave plate 21 and the focusing mirror 24 are removed, and the polarization separation film 45A is replaced with a half mirror.

[0081] In the display unit 120 of the first comparative example, the brightness of the image light ML at the time of being emitted by the display element 11 is assumed to be 100%. The image light ML emitted by the display element 11 is reflected twice as light La1 containing a component of s-polarized light s and a component of p-polarized light p on the inner side surface 41b and the outer side surface 41c of the first prism 41, and then travels toward the half mirror. A portion of the light La1 is reflected by the half mirror, and then travels toward the quarter wavelength plate 51 as light Lb2, and then travels toward the transmissive reflective mirror 56 as light Lb3 after passing through the quarter wavelength plate 51. Here, when the reflectivity of the half mirror is 50%, the brightness of the light Lb2 and the light Lb3 is 50% of the brightness of the light La1 immediately before being reflected by the half mirror, and is 50% of the brightness of the image light ML at the time of being emitted. Next, the light Lb3 is reflected by the transmissive reflective mirror 56, and then travels toward the quarter wavelength plate 51 as light Lb4, and then travels toward the half mirror as light Lb5 after passing through the quarter wavelength plate 51. Here, when the transmittance of the transmission mirror 56 is 50%, the brightness of the light Lb4 and Lb5 is 50% of the brightness of the light Lb4 just before being reflected by the transmission mirror 56, and is 25% of the brightness of the image light ML when it is emitted. Then, a part of the light Lb5 passes through the half mirror and heads toward the emission pupil EP as the light Lb6. Here, when the transmittance of the half mirror is 50%, the brightness of the light Lb6 is 50% of the brightness of the light Lb5 just before passing through the half mirror, and is 12.5% ​​of the brightness of the image light ML when it is emitted.

[0082] Furthermore, in the first comparative example, the external light OL is incident on the second lens 53 from the transmission reflector 56 as the light Le1. It is assumed that the brightness of the external light OL immediately before being incident on the transmission reflector 56 is 100%. However, the brightness of the image light ML at the time of emission is not necessarily the same as the brightness of the external light OL immediately before being incident. The light Le1 passes through the transmission reflector 56 and is directed toward the 1 / 4 wavelength plate 51 as the light Le2. Here, when the transmittance of the transmission reflector 56 is 50%, the brightness of the light Le2 is 50% of the brightness of the external light OL immediately before being incident. The light Le1 and the light Le2 contain a left-handed circularly polarized light c component and a right-handed circularly polarized light c component. When the light Le2 passes through the 1 / 4 wavelength plate 51, it is incident on the second prism 42 from the outer side surface 42c as the light Le3 and is directed toward the half mirror. The left-handed circularly polarized light c component and the right-handed circularly polarized light c component of the light Le2 are respectively converted into the s-polarized light s component and the p-polarized light p component of the light Le3 by passing through the 1 / 4 wavelength plate 51. A part of the s-polarized light s component and a part of the p-polarized light p component contained in the light Le3 pass through the half mirror regardless of the polarization direction and are emitted as the light Le4 toward the exit pupil EP. Here, when the transmittance of the half mirror is 50%, the brightness of the light Le4 is 50% of the brightness of the light Le3 immediately before passing through the half mirror, and is 25% of the brightness of the external light OL at the time of incidence.

[0083] According to the above estimation, in the first comparative example, the brightness of the light Lb6 originating from the image light ML among the lights reaching the exit pupil EP is 12.5% ​​of the brightness of the image light ML at the time of emission, and the brightness of the light Le4 originating from the external light OL is 25% of the brightness of the external light OL immediately before incidence. Fig.12 In the present embodiment and the first comparative example shown, the utilization efficiency of the image light ML from the display element 11 in the present embodiment is six times the utilization efficiency of the image light ML from the display element 11 in the first comparative example.

[0084] The display unit 220 of the second comparative example is equivalent to Fig.12 The display units 20 a and 20 b of the present embodiment shown in the figure are modified as follows: the second quarter wavelength plate 21 and the condensing reflector 24 are removed, and a polarization separation film is added between the lens portion 32 of the first lens 30 and the third lens 44 of the first prism 41 .

[0085] In the display unit 220 of the second comparative example, the brightness of the image light ML at the time of being emitted by the display element 11 is assumed to be 100%. The image light ML emitted by the display element 11 is directed to the polarization separation film as light La1 including the s-polarized light s component and the p-polarized light p component. The s-polarized light s component in the light La1 passes through the polarization separation film, is reflected twice by the inner side surface 41b and the outer side surface 41c of the first prism 41, and is directed to the polarization separation film 45A. Here, the brightness of the s-polarized light s component in the light La1 is 50% of the brightness of the light La1 immediately before passing through the polarization separation film 15, and is 50% of the brightness of the image light ML at the time of being emitted. Next, the s-polarized light s component in the light La1 is reflected by the polarization separation film 45A, and is directed to the 1 / 4 wavelength plate 51 as light Lb2, and is directed to the transmission reflector 56 as light Lb3 having passed through the 1 / 4 wavelength plate 51. Here, the brightness of the light Lb3 is the same as the brightness of the s-polarized light s component of the light La1 just before being reflected by the polarization separation film 45A, and is 50% of the brightness of the image light ML at the time of emission. The s-polarized light s of the light Lb2 passes through the 1 / 4 wavelength plate 51, thereby becoming the right-handed circularly polarized light c of the light Lb3. Then, the light Lb3 is reflected by the transmission reflector 56 and travels toward the polarization separation film 45A as the light Lb4. Here, when the transmittance and reflectance of the transmission reflector 56 are 50%, the brightness of the light Lb4 is 50% of the brightness of the light Lb3 just before being reflected by the transmission reflector 56, and is 25% of the brightness of the image light ML at the time of emission. In addition, the right-handed circularly polarized light c of the light Lb3 is reflected by the transmission reflector 56, thereby becoming the left-handed circularly polarized light c of the light Lb4. And when the light Lb3 passes through the 1 / 4 wavelength plate 51 again, the light Lb5 whose polarization is changed from the left-handed circularly polarized light c to the p-polarized light p is directed toward the polarization separation film 45A. Then, the light Lb5 passes through the polarization separation film 45A and is directed toward the exit pupil EP as the light Lb6. Here, the brightness of the light Lb6 is the same as the brightness of the light Lb5 immediately before passing through the polarization separation film 45A, which is 25% of the brightness of the image light ML at the time of emission.

[0086] Furthermore, in the second comparative example, the external light OL is incident on the second lens 53 from the transmission reflector 56 as the light Le1, a part of the light Le1 is directed toward the 1 / 4 wavelength plate 51 as the light Le2, and when passing through the 1 / 4 wavelength plate 51, it is directed toward the polarization separation film 45A as the light Le3, and a part of the light Le3 is transmitted through the polarization separation film 45A as the light Le4 and reaches the exit pupil EP. The brightness of the light Le3 in the second comparative example is Fig.12 The situation is the same as that of the light Le4 shown, which is 25% of the brightness of the external light OL immediately before the incidence.

[0087] According to the above estimation, in the second comparative example, the brightness of the light Lb6 originating from the image light ML among the lights reaching the exit pupil EP is 25% of the brightness of the image light ML at the time of emission, and the brightness of the light Le4 originating from the external light OL is 25% of the brightness of the external light OL immediately before the incident light. Fig.12 Comparing the present embodiment shown with the second comparative example, the utilization efficiency of the image light ML from the display element 11 in the present embodiment is three times the utilization efficiency of the image light ML from the display element 11 in the second comparative example.

[0088] Thus, according to this embodiment, the second focusing reflection portion CR2 provided inside the second prism 42 enables the component of the image light ML emitted by the display element 11 that does not reach the exit pupil EP in each comparative example to reach the exit pupil EP and be effectively utilized, thereby improving the utilization efficiency of the image light ML from the display element 11.

[0089] Fig.13 This is a diagram for explaining an example of the structure of the prism light guide member 48 . Fig.14 4 is a diagram for explaining an example of assembling the prism light guide component 48. The prism light guide component 48 is formed by joining four components 411, 421, 422, and 423. In addition, the components constituting the prism light guide component 48 are not limited to four, and the number of components can be appropriately changed by changing the shape of the components. The third lens 44 can also be pre-joined to the component 411 constituting the first prism 41.

[0090] The second prism 42 is formed by combining the second component 421 on the upper side, the fourth component 423 on the lower side, and the third component 422 in the middle. The second quarter wavelength plate 21 may be pre-joined to the second component 421. Alternatively, the second quarter wavelength plate 21 may be first joined to the third component 422. In addition, the concave surface 24a of the focusing reflector 24 may be pre-formed on the fourth component 423. Alternatively, the concave surface 24a of the focusing reflector 24 may be first formed on the third component 422. In either case, the prism light guide component 48 is formed by joining the first component 411, the second component 421, the third component 422, and the fourth component 423. These joints may also be performed using an adhesive.

[0091] Reference Fig.15 , an example of the structure and assembly of the first display unit 20a constituting the first virtual image display device 100A is described. Fig.15In the figure, regions ER1 to ER5 are stereoscopic diagrams for explaining the assembly process of the first display unit 20a. First, as shown in region ER1, the first prism 41 and the second prism 42 are prepared as described above. The first prism 41 and the second prism 42 are formed of, for example, glass or resin. The third lens 44 may also be pre-bonded to the first prism 41. On the inclined surface 41d of the first prism 41, a polarization separation film 45A serving as an inclined reflector portion 45 is formed by vacuum evaporation or other methods. As shown in region ER2, the first prism 41 and the second prism 42 are bonded at the inclined surfaces 41d and 42d to obtain a prism light guide component 48 or a first flat plate-shaped component 40. Next, as shown in region ER3, a quarter wavelength plate 51 is pasted opposite to the outer side surfaces 41c and 42c of the first flat plate-shaped component 40 shown in regions ER1 and ER2. At this time, a pair of thin adhesives, i.e., spacers 61, are arranged between the outer side surfaces 41c, 42c of the first flat plate-shaped member 40 and the 1 / 4 wavelength plate 51, and a gap is formed between the outer side surfaces 41c, 42c of the first flat plate-shaped member 40 and the 1 / 4 wavelength plate 51. As shown in region ER4, a second lens 53 is adhered to an appropriate position on the surface of the 1 / 4 wavelength plate 51. A transmission reflector 56 is formed on the surface of the second lens 53. Next, as shown in region ER5, an optical element 58 is adhered to the 1 / 4 wavelength plate 51 and the like. At this time, the compensation lens 54 and the second lens 53 of the optical element 58 are positioned and engaged with each other. In addition, the compensation plate 55 of the optical element 58 and the 1 / 4 wavelength plate 51 are joined to each other. Through the above, the assembly of the first display unit 20a is completed.

[0092] In the above description, the first display unit 20 a is manufactured by assembling the second flat member 50 on the first flat member 40 . However, the first and second flat members 40 , 50 may be assembled separately and then joined together.

[0093] 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 or optical unit, and comprises: a display element 11 emitting image light ML; a first lens 30, on which the image light ML from the display element 11 is incident; a first prism 41 on which the image light ML having passed through the first lens 30 is incident; a second prism 42 joined to the first prism 41 to form a prism light guide member 48 in the shape of a parallel flat plate; a polarization separation film 45A of an inclined reflector portion 45 disposed at a junction between the first prism 41 and the second prism 42 and reflecting a first portion of the image light ML guided in the first prism 41; and a polarization separation film 45A disposed opposite to an outer side surface 41c of the first prism 41 on which the first portion of the image light ML reflected by the inclined reflector portion is incident. A plano-convex second lens 53; a transmission mirror 56 formed on the convex surface 53g of the second lens 53, reflecting a portion of the image light ML reflected by the tilted mirror portion 45 toward the tilted mirror portion; a first 1 / 4 wavelength plate arranged between the outer side surface 41c of the first prism 41 and the second lens 53; a compensation lens 54 having a concave surface 54f joined to the convex surface 53g of the second lens 53 via the transmission mirror 56 and a plane 55g parallel to the outer side surface 41c of the first prism 41; a focusing mirror 24 arranged in the second prism 42, reflecting a second portion of the image light ML that passes through the tilted mirror portion 45 and is reflected by the inner side surface 42b of the second prism 42; and a second 1 / 4 wavelength plate 21 arranged between the inner side surface 42b of the second prism 42 and the focusing mirror 24.

[0094] In the virtual image display device 100A, 100B or the optical unit 100, a virtual image is directly formed without forming an intermediate image. Therefore, the refractive power is ensured by the first lens 30, the second lens 53 and the transmission reflector 56, and the increase in the optical path length can be suppressed and the magnification can be ensured, thereby avoiding the enlargement of the optical system. In addition, even if there is a two-faceted reflective component in front of the eye, by providing the second condensing reflective portion CR2 inside the second prism 42, the utilization efficiency of the image light ML from the display element 11 can be improved, and the brightness of the image light ML in the exit pupil EP can be improved, and the relative brightness of the image light ML to the brightness of the external light OL can be improved.

[0095] In the first embodiment described above, a configuration example is shown in which a non-polarizing panel such as an organic EL display is used as the display element 11. As a modification of this configuration example, the display element 11 may also be a micro LED, a liquid crystal laser backlight, etc. However, in the case where the light source of the display element 11 emits image light ML other than a non-polarized state, in order to obtain a desired polarization state in the polarization separation film 45A, for example, a quarter wavelength plate may be added between the first lens 30 and the third lens 44.

[0096] In the first embodiment described above, a structural example in which the reflectivity of the focusing reflector 24 is 100% is shown. As a modified example of this structural example, the focusing reflector 24 may also be a half-mirror with a reflectivity less than 100%, an angle selective film whose reflectivity varies depending on the incident angle, or the like. When the angle selective film is used as the focusing reflector 24, the reflectivity of the angle selective film may be made higher as the incident angle is smaller, such as when the light is incident on the focusing reflector 24 from the front, and the transmittance of the angle selective film may be made higher as the incident angle is larger, such as when the light is incident on the focusing reflector 24 from a horizontal angle. By using such an angle selective film as the focusing reflector 24, it is possible to take into account both the transparency of the focusing reflector 24 for the external light OL and the improvement of the utilization efficiency of the image light ML.

[0097] Second embodiment

[0098] 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.

[0099] like Fig.16 As shown, the virtual image display device 100A, 100B of the present embodiment has a half mirror 45B as the tilted mirror portion 45 instead of the polarization separation film 45A of the first embodiment. The half mirror 45B reflects a part of the image light ML and a part of the external light OL and partially transmits them. As an example, the reflectivity and transmittance of the half mirror 45B can also be 50%. Hereinafter, the polarization separation film 45A and the half mirror 45B are sometimes collectively referred to as the tilted mirror portion 45.

[0100] Assume that the brightness of the image light ML at the moment of being emitted by the display element 11 is 100%. The light La1 as the image light ML emitted by the display element 11 is reflected twice by the inner side surface 41b of the first prism 41 and the outer side surface 41c of the first prism 41 and then goes to the half mirror 45B. A part of the light La1 is reflected by the half mirror 45B and goes to the quarter wavelength plate 51 as the light Lb2, and goes to the transmission mirror 56 as the light Lb3 having passed through the quarter wavelength plate 51. The brightness of the light Lb2 and Lb3 is 50% of the light La1 immediately before being reflected by the half mirror 45B, and is 50% of the brightness of the image light ML at the moment of being emitted. Next, a part of the light Lb3 is reflected by the transmission mirror 56 and goes to the quarter wavelength plate 51 as the light Lb4, and goes to the quarter wavelength plate 51 as the light Lb5 having passed through the quarter wavelength plate 51. When the reflectivity of the transmission mirror 56 is 50%, the brightness of the light Lb4 and Lb5 is 50% of the brightness of the light Lb3 just before being reflected by the transmission mirror 56, and is 25% of the brightness of the image light ML at the time of emission. Then, a part of the light Lb5 passes through the half mirror 45B and travels toward the emission pupil EP as the light Lb6. The brightness of the light Lb6 is 50% of the brightness of the light Lb5 just before passing through the half mirror 45B, and is 12.5% ​​of the brightness of the image light ML at the time of emission.

[0101] In addition, another part of the light La1 as the image light ML emitted from the display element 11 passes through the half mirror 45B, and is directed to the 1 / 4 wavelength plate 21 as the light Lc2, and is directed to the condensing reflector 24 as the light Lc3 having passed through the 1 / 4 wavelength plate 21. The brightness of the light Lc2 and Lc3 is 50% of the light La1 immediately before passing through the half mirror 45B, and is 50% of the brightness of the image light ML at the time of emission. Then, the light Lc3 is reflected by the condensing reflector 24, and is directed to the 1 / 4 wavelength plate 21 as the light Lc4, and is directed to the half mirror 45B as the light Lc5 having passed through the 1 / 4 wavelength plate 21. The brightness of the light Lc4 and Lc5 is the same as the brightness of the light Lc3 immediately before being reflected by the condensing reflector 24, and is 50% of the brightness of the image light ML at the time of emission. Then, a part of the light Lc5 is reflected by the half mirror 45B, and is directed to the emission pupil EP as the light Lc6. The brightness of the light Lc6 is 50% of the brightness of the light Lc5 immediately before being reflected by the half mirror 45B, and is 25% of the brightness of the image light ML at the time of emission.

[0102] Furthermore, the external light OL enters the second lens 53 from the transmission reflector 56 as the light Le1. It is assumed that the brightness of the external light OL immediately before entering the transmission reflector 56 is 100%. However, the brightness of the image light ML at the time of emission is not necessarily the same as the brightness of the external light OL immediately before entering. Next, the light Le1 passes through the transmission reflector 56 and is directed to the 1 / 4 wavelength plate 51 as the light Le2, and is directed to the half mirror 45B as the light Le3 having passed through the 1 / 4 wavelength plate 51. When the transmittance of the transmission reflector 56 is 50%, the brightness of the light Le2 and Le3 is 50% of the brightness of the light Le1 immediately before passing through the transmission reflector 56, and is 50% of the brightness of the external light OL immediately before entering. Next, a part of the light Le3 passes through the half mirror 45B and is directed to the emission pupil EP as the light Le4. The brightness of the light Le4 is 50% of the brightness of the light Le3 immediately before passing through the half mirror 45B, and is 25% of the brightness of the external light OL immediately before entering.

[0103] According to the above estimates, Fig.16 Among the lights reaching the exit pupil EP, the total brightness of light Lb6 and light Lc6 originating from the image light ML is 37.5% of the brightness of the image light ML at the time of emission, and the brightness of light Le4 originating from the external light OL is 25% of the brightness of the external light OL just before incidence.

[0104] Fig.17 Show Fig.16 The virtual image display devices 100A and 100B according to the present embodiment are shown as other configuration examples. Fig.17 The virtual image display devices 100A and 100B are equivalent to Fig.16 The virtual image display devices 100A and 100B shown in the figure are modified as follows. That is, a polarization separation film 45C is provided as the tilted reflector portion 45 instead of the half mirror 45B. The polarization separation film 45C reflects 50% of the s-polarized light s component included in the incident light and transmits the remaining 50%. In addition, the polarization separation film 45C transmits the p-polarized light p component included in the incident light.

[0105] Assume that the brightness of the image light ML at the time of emission from the display element 11 is 100%. The light La1 as the image light ML emitted from the display element 11 is reflected twice by the inner side surface 41b of the first prism 41 and the outer side surface 41c of the first prism 41 and then travels toward the polarization separation film 45C. A part of the s-polarized light s component in the light La1 is reflected by the polarization separation film 45C and travels toward the 1 / 4 wavelength plate 51 as light Lb2. The polarized light of the light Lb2 is s-polarized light s, and the brightness of the light Lb2 is 50% of the brightness of the s-polarized light s component contained in the light La1 immediately before being reflected by the polarization separation film 45C, and is 25% of the brightness of the image light ML at the time of emission. When the light Lb2 passes through the 1 / 4 wavelength plate 51, it travels toward the transmission reflector 56 as light Lb3 whose polarization is changed from s-polarized light s to circularly polarized light c. Then, a part of the light Lb3 is reflected by the transmission reflector 56 and travels toward the 1 / 4 wavelength plate 51 as light Lb4. When the reflectivity of the transmission reflector 56 is 50%, the brightness of the light Lb4 is 50% of the brightness of the light Lb3 just before being reflected by the transmission reflector 56, and is 12.5% ​​of the brightness of the image light ML at the time of emission. Here, when the light Lb4 passes through the 1 / 4 wavelength plate 51, it becomes the light Lb5 of p-polarized light p as circularly polarized light c and moves toward the polarization separation film 45C. Then, the light Lb5 passes through the polarization separation film 45C and moves toward the emission pupil EP as light Lb6. The brightness of the light Lb6 is the same as the brightness of the light Lb5 just before passing through the polarization separation film 45C, and is 12.5% ​​of the brightness of the image light ML at the time of emission.

[0106] Furthermore, a part of the s-polarized light s component and the p-polarized light p component included in the light La1 as the image light ML emitted from the display element 11 passes through the polarization separation film 45C and is directed toward the 1 / 4 wavelength plate 21 as the light Lc2. The brightness of the light Lc2 is the sum of 50% of the brightness of the s-polarized light s component included in the light La1 immediately before passing through the polarization separation film 45C and 100% of the brightness of the p-polarized light p component included in the light La1 immediately before passing through the polarization separation film 45C, and is 75% of the brightness of the image light ML at the time of emission. When passing through the 1 / 4 wavelength plate 21, the light Lc2 is directed toward the focusing reflector 24 as the light Lc3 in which the s-polarized light s component and the p-polarized light p component are respectively converted into the right-handed circularly polarized light c component and the left-handed circularly polarized light c component. The brightness of light Lc3 is the sum of the brightness of the right-handed circularly polarized light c component and the brightness of the left-handed circularly polarized light c component, which is 75% of the brightness of the image light ML at the time of emission. Then, light Lc3 is reflected by the focusing reflector 24 and is directed toward the 1 / 4 wavelength plate 21 as light Lc4. Through reflection by the focusing reflector 24, the right-handed circularly polarized light c component contained in light Lc3 is converted into the left-handed circularly polarized light c component contained in light Lc4, and the left-handed circularly polarized light c component contained in light Lc3 is converted into the right-handed circularly polarized light c component contained in light Lc4. The brightness of light Lc4 is the sum of the brightness of the left-handed circularly polarized light c component and the brightness of the right-handed circularly polarized light c component, which is 75% of the brightness of the image light ML at the time of emission. After the light Lc4 passes through the quarter wavelength plate 21, the light Lc5 contains the p-polarized light p component after the left-handed circularly polarized light c component of the light Lc4 is changed, and the s-polarized light s component after the right-handed circularly polarized light c component of the light Lc4 is changed. Therefore, the brightness of the p-polarized light p and s-polarized light s components contained in the light Lc5 after passing through the quarter wavelength plate 21 are respectively 25% and 50% of the brightness of the image light ML at the time of emission. Next, a part of the s-polarized light s component contained in the light Lc5 is reflected by the polarization separation film 45C and travels toward the exit pupil EP as the light Lc6. The brightness of the light Lc6 is 50% of the brightness of the s-polarized light s component contained in the light Lc5 immediately before being reflected by the polarization separation film 45C, and is 25% of the brightness of the image light ML at the time of emission.

[0107] Furthermore, the external light OL is incident on the second lens 53 from the transmission reflector 56 as the light Le1. It is assumed that the brightness of the external light OL immediately before being incident on the transmission reflector 56 is 100%. However, the brightness of the image light ML at the time of emission is not necessarily the same as the brightness of the external light OL immediately before being incident. Then, the light Le1 passes through the transmission reflector 56 and is directed toward the 1 / 4 wavelength plate 51 as the light Le2. When the transmittance of the transmission reflector 56 is 50%, the brightness of the light Le2 is 50% of the brightness of the light Le1 immediately before being transmitted through the transmission reflector 56 and 50% of the brightness of the external light OL immediately before being incident. The light Le1 and the light Le2 contain a left-handed circularly polarized light c component and a right-handed circularly polarized light c component. When the light Le2 passes through the 1 / 4 wavelength plate 51, it is incident on the second prism 42 from the outer side surface 42c as the light Le3 and is directed toward the polarization separation film 45C. The left-handed circularly polarized light c component and the right-handed circularly polarized light c component of the light Le2 are respectively converted into the s-polarized light s component and the p-polarized light p component of the light Le3 by passing through the 1 / 4 wavelength plate 51. Next, a part of the s-polarized light s component contained in the light Le3 and the p-polarized light p component contained in the light Le3 pass through the polarization separation film 45C and are directed toward the exit pupil EP as the light Le4. The p-polarized light p component in the light Le4 passes through the polarization separation film 45C, and a part of the s-polarized light s component passes through the polarization separation film 45C. When the transmittance of the polarization separation film 45C is 100% with respect to the p-polarized light p and 50% with respect to the s-polarized light s, the brightness of the p-polarized light p component in the light Le4 is 25% of the brightness of the external light OL immediately before the incidence, and the brightness of the s-polarized light s component is 12.5% ​​of the brightness of the external light OL immediately before the incidence. The brightness of the light Le4 is 75% of the brightness of the light Le3 immediately before passing through the polarization separation film 45C, and is 37.5% of the brightness of the external light OL immediately before being incident.

[0108] According to the above estimates, Fig.17 Among the lights reaching the exit pupil EP, the total brightness of light Lb6 and light Lc6 originating from the image light ML is 37.5% of the brightness of the image light ML at the time of emission, and the brightness of light Le4 originating from the external light OL is 37.5% of the brightness of the external light OL just before incidence.

[0109] Thus, according to this embodiment, Fig.16 and Fig.17 In the structural example shown, both Fig.12 Compared with the two comparative examples, the utilization efficiency of the image light ML from the display element 11 is improved by utilizing the second focusing reflection portion CR2 provided inside the second prism 42 to enable the component of the image light ML emitted by the display element 11 that did not reach the exit pupil EP in each comparative example to reach the exit pupil EP and be effectively utilized.

[0110] In addition, in this embodiment, a portion of the image light ML is along Fig.18 The optical path shown in FIG. 1 may generate unwanted stray light Ga. In order to suppress the generation of such stray light Ga, as Fig.16 Half mirror 45B, Fig.17 The polarization separation film 45C and Fig.16 and Fig.17 A part or all of the reflection area included in the transmission reflector 56 may also use an angle selective mirror whose transmittance varies according to the incident angle of the incident light. The angle selective mirror can suppress the generation of stray light Ga by allowing the so-called horizontal light, i.e., light with an incident angle greater than a predetermined threshold value, to pass through without reflecting it. As an example, by setting the transmittance of the corresponding reflection area to be higher than a predetermined threshold value, the portion of the image light incident at an incident angle greater than the predetermined threshold value relative to the inclined reflector portion 45 and / or the transmission reflector 56 is not reflected but passed through, thereby suppressing the generation of stray light caused by the image light.

[0111] In addition, Fig.16 and Fig.17 In the virtual image display devices 100A and 100B of the present embodiment shown, a quarter wavelength plate, for example, may be added between the first lens 30 and the third lens 44 depending on the type of the display element 11 so that the image light ML in the polarization separation film 45A etc. obtains a desired polarization state.

[0112] Third embodiment

[0113] 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.

[0114] Reference Fig.19 and Fig. 20 , a case where the condensing reflector 24 of the above-mentioned first embodiment and second embodiment is divided into a plurality of parts will be described. Fig. 20 Indicated in Fig.19 The result of observing the condensing reflector 24 in the observation direction OD is shown.

[0115] Fig. 20 The region FR1 shows the shape of the condensing reflector 24 in the first embodiment and the second embodiment. Fig.19 The focusing reflector 24 is integrated into a concave surface. Fig. 20 The region FR2 shows the shape of the condensing reflector 25 of this embodiment. Fig. 20The condensing reflector 25 includes a plurality of partial reflective surfaces 25a, 25b, and 25c. The plurality of partial reflective surfaces 25a, 25b, and 25c reflect the components of the image light ML that have passed through the polarization separation films 45A and 45C or the half mirror 45B as the tilted reflector portion toward a plurality of regions included in the exit pupil EP.

[0116] By appropriately dividing the focusing reflector 25 into a plurality of partial reflection surfaces 25a, 25b, and 25c, the distribution of the brightness of the image light ML observed in the exit pupil EP can be adjusted to a desired distribution. In addition, by appropriately setting the positions and shapes of the plurality of partial reflection surfaces 25a, 25b, and 25c, the brightness unevenness of the image light ML observed in the exit pupil EP can also be reduced. As an example, the brightness of the image light ML observed in the exit pupil EP can also be adjusted by selectively configuring the partial reflection surfaces 25a, 25b, and 25c at the positions of the partially reflected image light ML with relatively low brightness toward the exit pupil EP. Furthermore, the distribution of the reflectivity and transmittance of the plurality of partial reflection surfaces 25a, 25b, and 25c can also be set to reduce the brightness unevenness. As an example, the brightness of the image light ML observed in the exit pupil EP may be adjusted by setting the reflectivity of the area reflecting the image light ML at the position of the partial reflection surface 25a, 25b, 25c facing the image light ML with relatively low brightness in the exit pupil EP to be relatively high (or the transmittance to be relatively low). In addition, the brightness of the image light ML observed in the exit pupil EP may be adjusted by setting the reflectivity of the area reflecting the image light ML at the position of the partial reflection surface 25a, 25b, 25c facing the image light ML with relatively high brightness in the exit pupil EP to be relatively low (or the transmittance to be increased). In addition, the positions of the plurality of partial reflection surfaces 25a, 25b, 25c in the second prism 42 may be finely adjusted in the direction of the observation direction OD. In this way, the positions, shapes, reflectivities, and transmittances of the multiple partial reflecting surfaces 25a, 25b, and 25c of the focusing reflector 25 can be appropriately set according to the brightness distribution when the first part of the image light ML traveling in the first optical path P1 reaches the inner surface 42b of the second prism 42, so as to reduce the uneven brightness when the first part of the image light ML traveling in the first optical path P1 and the second part traveling in the second optical path P2 reach the inner surface 42b of the second prism 42.

[0117] In this way, by replacing the condensing reflective mirror 24 with the condensing reflective mirror 25 having the plurality of partial reflection surfaces 25 a , 25 b , and 25 c , it is possible to adjust the brightness, reduce the uneven brightness, and the like.

[0118] Fourth embodiment

[0119] Hereinafter, a virtual image display device according to a fourth embodiment will be described. The virtual image display device according to the fourth embodiment is a partial modification of 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.

[0120] Reference Fig.21 and Fig. 22 , the case where chromatic aberration can be corrected by changing the second lens 53 in the first embodiment and the second embodiment to a lens group composed of a plurality of materials is described. Fig. 22 The region GR1 shows the optical path of the light incident on the second lens 53 in the first embodiment and the second embodiment. Fig. 22 The region GR2 shows the optical path of the light incident on the second lens 530 of this embodiment.

[0121] like Fig.21 As shown, the second lens 530 of the present embodiment includes a first partial lens 531 and a second partial lens 532. The first partial lens 531 is arranged at a position opposite to the first 1 / 4 wavelength plate 51. The second partial lens 532 is arranged between the first partial lens 531 and the transmission reflector 56. The first partial lens 531, the second partial lens 532 and the transmission reflector 56 can also be integrated. At this time, it is also possible that the first partial lens 531 is a plano-concave lens having a flat surface and a concave surface, and the second partial lens 532 is a convex lens having two convex surfaces, and the concave surface of the first partial lens 531 is complementary to the convex surface of one side of the second partial lens 532. The shape obtained by joining the first partial lens 531 and the second partial lens 532 of the present embodiment can also be the same as the shape of the second lens 53 in the first and second embodiments.

[0122] like Fig. 22 As shown, by appropriately selecting the materials of the first lens segment 531 and the second lens segment 532, the optical path in the second lens 530 composed of the first lens segment 531 and the second lens segment 532 can be changed relative to the second lens 53 composed of a separate material, and as a result, chromatic aberration can be corrected without changing the optical path length. However, from the viewpoint of making the first optical path length and the second optical path length substantially the same, it is preferred that the material of the second lens segment 532 is the same as that of the second prism 42.

[0123] Modifications and others

[0124] The present invention has been described based on the above embodiments, but the present invention is not limited to the above embodiments, 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.

[0125] 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 by the support device 100C.

[0126] 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 .

[0127] In the first flat plate-shaped member 40 , the third lens 44 may be omitted.

[0128] Instead of bonding the first prism 41 and the third lens 44 together, the first prism 41 may be formed by integrating a lens portion corresponding to the third lens 44 .

[0129] 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 .

[0130] Depending on the type of the first image forming element 11 a as a light source, a polarizing plate may be provided between the first lens 30 and the third lens 44 .

[0131] The first image forming element 11 a may be a scanning type display device including a laser light source and a scanning mirror.

[0132] A half mirror may be used instead of the polarization separation film 45A.

[0133] The virtual image display device in a specific embodiment is a direct virtual image type virtual image display device, which comprises: a display element that emits image light; a first lens, on which the 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, which is joined to the first prism to form a parallel flat plate-shaped prism light-guiding component; an inclined reflector portion, which is arranged at the junction of the first prism and the second prism and reflects a first portion of the image light guided in the first prism; a plano-convex second lens, which is connected to the outer side surface of the first prism on which the first portion of the image light reflected by the inclined reflector portion is incident. Arranged oppositely; a transmission reflector formed on the convex surface of the second lens, reflecting a portion of the image light reflected by the tilted reflector portion toward the tilted reflector portion; a first 1 / 4 wavelength plate arranged between the outer side surface of the first prism and the second lens; a compensation lens having a concave surface joined to the convex surface of the second lens via the transmission reflector and a surface parallel to the outer side surface of the first prism; a focusing reflector arranged in the second prism, reflecting a second portion of the image light that passes through the tilted reflector portion and is reflected by the inner side surface of the second prism; and a second 1 / 4 wavelength plate arranged between the inner side surface of the second prism and the focusing reflector.

[0134] 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 transmission reflector, and the increase in the optical path length can be suppressed and the magnification can be ensured, thereby avoiding the enlargement of the optical system. By having a focusing reflector and a second 1 / 4 wavelength plate, in addition to the first part of the image light emitted from the display element that is reflected by the inclined reflector part, the second part that passes through the inclined reflector part can also reach the exit pupil EP and be effectively utilized. As a result, the utilization efficiency of the image light from the display element is improved, and even if there are two reflective components at the front of the eye, such as the inclined reflector part 45 and the transmission reflector 56, the brightness of the image light reaching the exit pupil can be increased.

[0135] In a specific embodiment of a virtual image display device, the tilted reflector portion is provided with a polarization separation film that reflects image light according to the polarization direction, the first lens, the prism light guide component, the polarization separation film, the second lens, the transmission reflector, and the first 1 / 4 wavelength plate constitute a single microscope type imaging optical system that forms 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 transmission reflector, and the prism light guide component can be miniaturized, and the display element and the first lens can also be miniaturized.

[0136] In a virtual image display device in a specific embodiment, the focusing mirror is arranged at a position where the length of the first optical path is substantially the same as the length of the second optical path, the first optical path being the optical path in which the first part of the image light is reflected by the polarization separation film, then reflected by the transmission mirror, passes through the polarization separation film and reaches the inner side surface of the second prism, and the second optical path being the optical path in which the second part of the image light passes through the polarization separation film, then reflected by the focusing mirror, then reflected by the polarization separation film and reaches the inner side surface of the second prism. In this case, the magnification of the image light traveling in the first optical path and the image light traveling in the second optical path can be made the same.

[0137] In a specific embodiment of the virtual image display device, the second prism and the second lens are formed of substantially the same material, and the focusing reflector focuses the second portion of the image light at a curvature substantially the same as the curvature of the convex surface of the second lens. In this case, the image light traveling in the first optical path and the image light traveling in the second optical path can have the same magnification.

[0138] In a specific embodiment of the virtual image display device, the tilted mirror portion and a part of the reflective region in the transmission mirror transmit a part of the second portion of the image light. In this case, the generation of stray light caused by the image light can be suppressed.

[0139] In a virtual image display device of a specific embodiment, the transmittance of a part of the second part of the image light when the part of the reflection surface transmits the part of the image light varies depending on the incident angle of the second part of the image light incident on the part of the reflection surface. In this case, by setting the transmittance of the corresponding reflection area to be higher than a predetermined threshold value, the part of the image light incident on the inclined reflector portion and / or the transmission reflector at an incident angle greater than the predetermined threshold value is not reflected but transmitted, thereby suppressing the generation of stray light caused by the image light.

[0140] In a specific embodiment of the virtual image display device, the condensing reflector includes a plurality of partial reflective surfaces, and the plurality of partial reflective surfaces are configured to reflect the second portion of the image light to different regions of the exit pupil, respectively. In this case, the distribution of the brightness of the image light in the exit pupil can be adjusted.

[0141] In a specific embodiment of the virtual image display device, the reflectivity of each of the plurality of partial reflection surfaces is set to reduce brightness unevenness when the first and second portions of the image light reach the inner surface of the second prism. In this case, unevenness of light from the image light in the exit pupil can be reduced.

[0142] In a specific embodiment of the virtual image display device, the second lens includes: a first partial lens, which is opposite to the first 1 / 4 wavelength plate; and a second partial lens, which is arranged between the first partial lens and the transmission reflector, and the second partial lens is made of the same material as the second prism. In this case, by appropriately selecting the material of the first partial lens, chromatic aberration can be suppressed.

[0143] In a specific embodiment of the virtual image display device, the polarization separation film reflects a first portion of s-polarized light in the image light reaching from the first prism and transmits a first portion that is reflected by the transmission mirror and returns through the first quarter wavelength plate to become p-polarized light.

[0144] In a virtual image display device in a specific embodiment, the polarization separation film transmits the second portion of p-polarized light in the image light reaching from the first prism, and reflects the second portion that is reflected by the condensing reflector and passes through the second quarter wavelength plate to become s-polarized light.

[0145] In a specific embodiment of the virtual image display device, the first quarter wavelength plate is disposed apart from the outer side surface of the first prism. In this case, it is easy to ensure that the image light is reflected inside the outer side surface of the first prism.

[0146] 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.

[0147] 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; an inclined reflector portion, which is provided at a joint portion between the first prism and the second prism, and reflects a first portion of the image light guided in the first prism; a plano-convex second lens, which faces the outer side of the first prism on which the first portion of the image light reflected by the inclined reflector portion is incident. The invention relates to a first prism having an outer surface and an outer surface of the first prism and an inner surface of the second prism. The first prism has an outer surface and an inner surface of the second prism and an inner surface of the second prism and an inner surface of the second prism and an inner surface of the second prism and an inner surface of the second prism and an outer surface of the first ...

Claims

1. A direct virtual image type virtual image display device, comprising: a display element for emitting image light; a first lens, into which the image light from the display element is incident; a first prism, onto which the image light having passed 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; an inclined reflector portion, which is disposed at a junction of the first prism and the second prism, and reflects a first portion of the image light guided in the first prism; A plano-convex second lens disposed opposite to an outer surface of the first prism on which the first portion of the image light reflected by the inclined reflector portion is incident; a transmission reflector formed on a convex surface of the second lens and reflecting a portion of the image light reflected by the tilted reflector portion toward the tilted reflector portion; a first 1 / 4 wavelength plate, disposed between the outer side surface of the first prism and the second lens; a compensating lens having a concave surface joined to the convex surface of the second lens via the transmission reflector and a surface parallel to the outer side surface of the first prism; a condensing reflector disposed inside the second prism and reflecting a second portion of the image light that passes through the inclined reflector portion and is reflected by an inner side surface of the second prism; as well as The second quarter wavelength plate is disposed between the inner side surface of the second prism and the focusing reflector.

2. The virtual image display device according to claim 1, wherein: The tilted reflector portion includes a polarization separation film that reflects the image light according to a polarization direction. The first lens, the prism light guide member, the polarization separation film, the second lens, the transmission reflector, and the first quarter wavelength plate constitute a single microscope type imaging optical system that forms an erect image. The first prism diverges the image light and performs two internal reflections.

3. The virtual image display device according to claim 2, wherein: The focusing reflector is arranged at a position so that the length of the first optical path is approximately the same as the length of the second optical path. The first optical path is an optical path in which the first part of the image light is reflected by the polarization separation film, then reflected by the transmission reflector, passes through the polarization separation film and reaches the inner surface of the second prism. The second optical path is an optical path in which the second part of the image light passes through the polarization separation film, then reflected by the focusing reflector, is reflected by the polarization separation film and reaches the inner surface of the second prism.

4. The virtual image display device according to claim 3, wherein: The second prism and the second lens are formed of substantially the same material, The condensing reflector condenses the light at a curvature substantially the same as the curvature of the convex surface of the second lens when reflecting the second portion of the image light.

5. The virtual image display device according to claim 1, wherein: A portion of the reflecting surface included in the inclined reflector portion and / or the transmissive reflector transmits a portion of the second portion of the image light.

6. The virtual image display device according to claim 5, wherein: The transmittance of the portion of the reflecting surface when transmitting the portion of the second portion of the image light varies depending on an incident angle of the second portion of the image light on the portion of the reflecting surface.

7. The virtual image display device according to claim 1, wherein: The focusing reflector comprises a plurality of partially reflecting surfaces, The plurality of partial reflection surfaces are arranged to respectively reflect the second portion of the image light toward mutually different regions of the exit pupil.

8. The virtual image display device according to claim 7, wherein: The reflectivity of each of the plurality of partial reflection surfaces is set to reduce brightness unevenness when the first and second parts of the image light reach the inner surface of the second prism based on brightness distribution when the first part of the image light reaches the inner surface of the second prism.

9. The virtual image display device according to claim 1, wherein: The second lens has: A first partial lens, which is opposite to the first quarter wavelength plate; and A second partial lens is arranged between the first partial lens and the transmission reflector, The second partial lens is made of the same material as the second prism.

10. The virtual image display device according to claim 2, wherein: The polarization separation film reflects the first portion of s-polarized light in the image light reaching from the first prism, and transmits the first portion that is reflected by the transmission mirror and returns through the first quarter wavelength plate to become p-polarized light.

11. The virtual image display device according to claim 2, wherein: The polarization separation film transmits the second portion of the p-polarized light in the image light reaching from the first prism, and reflects the second portion of the p-polarized light by being reflected by the condensing reflector and passing through the second quarter wavelength plate to become the second portion of the s-polarized light.

12. The virtual image display device according to claim 1, wherein: The first quarter-wave plate is disposed apart from the outer side surface of the first prism.

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

14. A direct virtual image optical unit comprising: A first lens having positive refractive power, the image light from the display element emitting the image light being incident on the first lens; a first prism, onto which the image light having passed 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; an inclined reflector portion, which is disposed at a junction of the first prism and the second prism, and reflects a first portion of the image light guided in the first prism; A plano-convex second lens disposed opposite to an outer surface of the first prism on which the first portion of the image light reflected by the inclined reflector portion is incident; a transmission reflector formed on a convex surface of the second lens and reflecting a portion of the image light reflected by the tilted reflector portion toward the tilted reflector portion; a first 1 / 4 wavelength plate, disposed between the outer side surface of the first prism and the second lens; a compensating lens having a concave surface joined to the convex surface of the second lens via the transmission reflector and a surface parallel to the outer side surface of the first prism; a condensing reflector disposed inside the second prism and reflecting a second portion of the image light that passes through the inclined reflector portion and is reflected by an inner side surface of the second prism; as well as The second quarter wavelength plate is disposed between the inner side surface of the second prism and the focusing reflector.

Images