Light guide member and display device

Abstract

To provide a light guide member and a display device that emit image light scatteringly.SOLUTION: A light guide member 300 comprises: a beam emission unit 304 for emitting light-guided image light to the outside; and a first face 305 for reflecting the image light toward the beam emission unit 304, causing it to be emitted from the beam emission unit 304. The plurality of first faces 305 are arranged in a direction in which the image light is guided, and a downstream-side first face 305F among the plurality of first faces 305 that is arranged downstream of the direction in which the image light is guided is inclined, with respect to upstream-side first faces 305B, 305D that are arranged downstream of the direction in which the image light is guided, in a direction in which a distance from the beam emission unit 304 increases on the downstream side of the direction in which the image light is guided.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a light guide member and a display device. [Background technology]

[0002] Patent Document 1 discloses a light guide plate comprising a light entrance section that takes in image light, a light guiding section having first and second total reflection surfaces extending oppositely and guiding the image light taken in from the light entrance section by total reflection at the first and second total reflection surfaces, and a light exit section having an image extraction section that enables the image light incident through the light guiding section to be extracted to the outside by bending the optical path, wherein the image extraction section is comprised of an alternating arrangement of a plurality of first element surfaces that extend at an angle toward the inside of the light guiding section on the far side in the light guiding direction of the light guiding section with the second total reflection surface as a reference in order to reflect the image light guided by the light guiding section, and a plurality of second element surfaces that extend at an obtuse angle to the first element surfaces. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5703875 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a light guide member and a display device that diverge and emits incident light. [Means for solving the problem]

[0005] The present invention Light guide member an interface that outputs the guided image light to the outside; The above Image light The above Reflected toward the interface The above a reflecting surface for causing the light to exit from the interface; When an XYZ orthogonal coordinate system is defined in which the direction in which the image light is guided is a Z direction, the direction perpendicular to the Z direction and perpendicular to the interface is a Y direction, and the direction perpendicular to the Z direction and parallel to the interface is an X direction, The reflective surface is The above Image light is guided Z A plurality of the electrodes are arranged in the direction. In a cross section parallel to the YZ plane of the XYZ orthogonal coordinate system, Among the multiple reflecting surfaces, The above Image light is guided Z A downstream reflecting surface disposed downstream in the direction with a slope of The image light is guided Z An upstream reflecting surface arranged upstream in the direction Compared with the slope of , The inclination of the downstream side reflection surface is closer to being parallel to the interface than the inclination of the upstream side reflection surface, and is closer to the interface side in the Z direction. Tilt. Effect of the Invention

[0006] According to the present invention, it is possible to provide a light guide member and a display device which diverge and emits incident light. [Brief description of the drawings]

[0007] [Figure 1] 1 is a diagram illustrating an example of a light-guiding member 300 according to an embodiment of the present invention and a virtual image display device 1000 using the light-guiding member 300. FIG. [Diagram 2] 10A and 10B are diagrams showing how light propagated through the light-guiding member 300 according to the present embodiment is emitted. [Diagram 3] 3 is a diagram showing light propagating within a light-guiding member 300 according to the present embodiment. FIG. [Figure 4] 3 is an explanatory diagram of an image extraction portion 303 in the light-guiding member 300 according to the present embodiment. FIG. [Diagram 5] 3 is a detailed explanatory diagram of an image extraction section 303 in the light-guiding member 300 according to the present embodiment. FIG. [Figure 6] 10 is an explanatory diagram of a modified example of the image extraction portion 303 in the light-guiding member 300 according to the present embodiment. FIG. [Figure 7] 11 is an explanatory diagram of a second modified example of the image extraction portion 303 in the light guide member 300 according to the present embodiment. FIG. [Figure 8] 13 is an explanatory diagram of a third modified example of the image extraction portion 303 in the light guide member 300 according to the present embodiment. FIG. [Figure 9] 13 is an explanatory diagram of a fourth modified example of the image extraction portion 303 in the light guide member 300 according to the present embodiment. FIG. [Figure 10]4 is an explanatory diagram of parameters of the light-guiding member 300 according to the present embodiment. FIG. [Figure 11] 10 is an explanatory diagram of parameters of an image extraction section 303 in the light-guiding member 300 according to the present embodiment. FIG. [Figure 12] 1 is a diagram showing an optical system layout of a virtual image display device 1000 according to the present embodiment. [Figure 13] 2 is an explanatory diagram of a spot diagram in the virtual image display device 1000 according to the present embodiment. FIG. [Figure 14] 1 is a diagram showing a simulation of a spot diagram at point A of the virtual image display 1000 according to the present embodiment. [Figure 15] 10 is a diagram showing a simulation of a spot diagram at point B of the virtual image display 1000 according to the present embodiment. FIG. [Figure 16] 11 is a diagram showing a simulation of a spot diagram at point C of the virtual image display 1000 according to the present embodiment. FIG. [Figure 17] 11 is a diagram showing a simulation of a spot diagram at point D of the virtual image display 1000 according to the present embodiment. FIG. [Figure 18] 10 is a diagram showing a simulation of a spot diagram at point E of the virtual image display 1000 according to the present embodiment. FIG. [Figure 19] 1A to 1C are diagrams illustrating various examples of usage states of the virtual image display device 1000 according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] 1 is a diagram showing an example of a light guiding member 300 according to an embodiment of the present invention and a virtual image display device 1000 using the same. The virtual image display device 1000 is an example of a display device, and includes an image display element 100 that emits and outputs image light of a display image, an optical system 200 that collimates and emits the image light from the image display element 100, and a light guiding member 300 as a virtual image display optical system.

[0009] The image display element 100 is a device that outputs image light of a display image that is the basis of a virtual image displayed through the light guide member 300. The image display element 100 is preferably an organic LED (OLED: Organic Light Emitting Diode) or a transmissive liquid crystal display element, but various other display methods can be applied. For example, a DMD (Digital Micromirror Device) can be applied as the image display element 100. Also, a TFT (Thin Film Transistor) or an LCOS (Liquid Crystal On Silicon) can be applied as the image display element 100. Furthermore, a MEMS (Micro Electro Mechanical Systems) can be applied as the image display element 100. Taking an OLED array as an example of the image display element 100, the size of the image display area (pixel array area) is, for example, "3 mm x 4 mm" and the number of pixels is about 10,000.

[0010] When the image display element 100 uses an LCOS or a DMD that requires a light source, the image display element 100 includes a light source for emitting illumination light to illuminate the image display surface of the image display element 100. Various light sources can be used, such as an LED (Light Emitting Diode), a semiconductor laser (Laser Diode: LD), or a discharge lamp.

[0011] The optical system 200 is an example of an incident optical system, and is composed of a plurality of optical lenses, a diaphragm, and the like.

[0012] The light guiding member 300 includes a light ray incident section 301, a light guiding section 302, an image extraction section 303, and a light ray emitting section 304. The light ray emitting section 304 is an example of an interface (boundary surface) that reflects the guided image light and emits it to the outside.

[0013] 1 shows a light path diagram of the center of the image display element 100 corresponding to a virtual image display in the horizontal direction. The image light emitted from the center of the image display element 100 is converted into angle information by the optical system 200 having a collimating optical system function, and enters the light guide member 300 from the light ray entrance part 301.

[0014] The light that enters light-guiding member 300 becomes a guided light flux, and propagates while repeatedly being totally reflected by the parallel opposing surfaces of light-guiding section 302 .

[0015] When light strikes the image extraction unit 303, the light is emitted from the light ray emitting unit 304 and enters the user's eye. When the user looks ahead through the light ray emitting unit 304 of the light guiding member 300, an image is formed on the retina as a "conjugate image of a virtual image," and the user can visually recognize a virtual image of the image light. That is, the user observes the image display element 10 through the light guiding member 300 due to the action of the optical system 200 between the image display element 10 and the light guiding member 300.

[0016] FIG. 2 is a diagram showing how light propagates through the light-guiding member 300 according to this embodiment and is then emitted.

[0017] As shown in FIG. 2, the image retrieval unit 303 includes at least a plurality of first surfaces 305 and a plurality of second surfaces 306 .

[0018] The first surface 305 is an example of a first inclined surface that is inclined so as to reduce the distance from the light beam emission section 304 in the direction in which the image light is guided, and is an example of a reflecting surface that reflects the image light toward the light beam emission section 304 and causes the image light to be emitted from the light beam emission section 304. The second surface 306 is an example of an opposing surface that is disposed between two adjacent first surfaces 305, is parallel to the light beam emission section 304, and faces the light beam emission section 304. A plurality of first surfaces 305 are disposed in the direction in which the image light is guided.

[0019] When the light propagates while repeatedly being totally reflected in the light guiding section 302 and hits the first surface 305, it is emitted from the light ray emitting section 304 and reaches the eye. Furthermore, by providing the second surface 306, the light can travel toward the back of the light guiding member 300 until it hits the first surface 305, and the light can be guided toward the light ray emitting section 304 even in the back of the light guiding member 300. In this way, it is possible to realize a virtual image display device 1000 that is capable of wide-angle display even if the light guiding member 300 is thin.

[0020] FIG. 3 is a diagram showing light propagating within the light-guiding member 300 according to this embodiment.

[0021] Fig. 3 shows light 201 propagating at angle θ1, which is the smallest reflection angle, and light 202 propagating at angle θ2, which is the largest reflection angle, with respect to light ray emission section 304, among light propagating by total reflection at upper surface 308 and lower surface 309 of light guiding section 302 of light guiding member 300, and shows light from pixels at both ends of image display element 100 within the plane of paper of Fig. 3. In other words, the viewing angle can be made wider as θ1 is made smaller and as θ2 is made larger.

[0022] FIG. 4 is an explanatory diagram of the image extraction section 303 in the light-guiding member 300 according to this embodiment.

[0023] When a virtual image is visually recognized by the image light emitted from the light-guiding member 300, it is conceivable that the divergence angle of the light beam emitted from the optical system 200 is adjusted to adjust the virtual image distance.

[0024] However, when a divergent light beam is emitted from the optical system 200, the propagation of the divergent light beam within the light-guiding member 300 can cause problems such as pixel shift, which results in double virtual images being observed.

[0025] On the other hand, when a parallel light beam is emitted from the optical system 200, the parallel light beam is emitted from the light-guiding member 300, and therefore the virtual image distance is infinite.

[0026] Therefore, in this embodiment, the divergence angle of the image light emitted from the light-guiding member 300 with respect to the incident light entering the light-guiding member 300 is adjusted to adjust the virtual image distance.

[0027] As an example, even if the light beam emitted from the optical system 200 is parallel light, the image light emitted from the light-guiding member 300 is divergent light, so that the virtual image distance is made finite.

[0028] 4, a plurality of first surfaces 305A-305F and a plurality of second surfaces 306A-306F are arranged in the direction in which the image light is guided. The second surfaces 306B-306F are each arranged between two adjacent first surfaces 305 among the plurality of first surfaces 305A-305F.

[0029] Here, among the multiple first surfaces 305, the downstream first surface 305F, which is arranged on the downstream side in the direction in which the image light is guided, is inclined in a direction in which the distance from the light beam emitting section 304 on the downstream side in the direction in which the image light is guided increases, relative to the upstream first surface 305D, which is arranged on the upstream side in the direction in which the image light is guided.

[0030] This makes it possible to make the angle between the emitted light (dotted line) reflected from the upstream first surface 305D and emitted from the light beam emission section 304, and the emitted light (solid line) reflected from the downstream first surface 305F and emitted from the light beam emission section 304, larger than the angle between the incident light incident on the upstream first surface 305D and the incident light incident on the downstream first surface 305F.

[0031] Similarly, the first surface 305D is inclined in a direction that increases the distance from the light emitting section 304 downstream in the direction in which the image light is guided, relative to the upstream first surface 305B that is arranged upstream in the direction in which the image light is guided.

[0032] In other words, each of the downstream first surfaces 305B to 305E is formed so that the further downstream it is positioned in the direction in which the image light is guided relative to the upstream first surface 305A, the greater the inclination angle in the direction in which the distance from the light emitting section 304 on the downstream side in the direction in which the image light is guided becomes.

[0033] The inclination angles of first surfaces 305A to 305E do not all have to be different. For example, first surface 305C disposed between first surfaces 305B and 305D may be formed so as to be parallel to either one of first surfaces 305B and 305D.

[0034] 4, the incident light incident on the upstream first surfaces 305B and 305D is parallel to the incident light incident on the downstream first surface 305F. This allows the light guiding member 300 to convert the emitted light reflected on the upstream first surfaces 305B and 305D and emitted from the light emitting portion 304, and the emitted light reflected on the downstream first surface 305F and emitted from the light emitting portion 304 into divergent light, without causing problems such as color shift caused by guiding non-parallel incident light.

[0035] Furthermore, the downstream first surface 305F is inclined in a direction that increases the distance from the light beam emission section 304 on the downstream side in the direction in which the image light is guided, relative to the upstream first surface 305E arranged adjacent to it on the upstream side in the direction in which the image light is guided.

[0036] This makes it possible to make the angle formed by the respective emitted lights reflected at the adjacent upstream first surface 305E and downstream first surface 305F and emitted from the light beam emitting section 304 larger than the angle formed by the respective incident lights incident on the upstream first surface 305E and downstream first surface 305F.

[0037] Here, the angle at which the downstream first surface 305F is inclined relative to the upstream first surface 305E is greater than 0.002 degrees and smaller than 0.210 degrees.

[0038] Thereby, the two emitted lights reflected by the adjacently arranged upstream first surface 305E and downstream first surface 305F, respectively, and emitted from the light emitting portion 304 can set the virtual image distance to about 0.3 to 2 m.

[0039] If the angle at which the downstream first surface 305F is inclined relative to the upstream first surface 305E exceeds the upper limit of 0.210 degrees, the virtual image distance becomes too close, making it difficult for the user to focus on the virtual image. On the other hand, if the angle at which the downstream first surface 305F is inclined relative to the upstream first surface 305E is less than the lower limit of 0.002 degrees, the virtual image distance becomes almost infinite. In contrast, in this embodiment, the virtual image distance is kept finite, making it easy for the user to focus on the virtual image.

[0040] A second surface 306F facing parallel to the light emitting portion 304 is provided between two adjacent first surfaces 305E, 305F.

[0041] As a result, the pupil can be enlarged and an eye box can be secured while maintaining a wide angle of view by two divergent lights that are reflected by the two first surfaces 305E and 305F and emitted from the light ray emitting part 304. In addition, more light can reach the first surface 305 on the back side of the light guiding member 300.

[0042] FIG. 5 is a detailed explanatory diagram of the image extraction portion 303 in the light-guiding member 300 according to this embodiment.

[0043] Fig. 5(a) is a diagram showing the image extraction unit 303 in the YZ plane, and is similar to Fig. 4. Fig. 5(b) is a diagram showing the image extraction unit 303 in the XZ plane.

[0044] 5, the XZ plane is a plane parallel to the light emitting unit 304, the Z direction is a direction in which the image light is guided and in which the multiple first surfaces 305A-305E are arranged, and the Y direction is a direction perpendicular to the XZ plane and the light emitting unit 304. As shown in Fig. 5(b), the shape of each of the multiple first surfaces 305A-305E in a cross section parallel to the XZ plane is formed into a convex shape toward the upstream side (-Z side) in the Z direction in which the image light is guided.

[0045] This allows the incident light incident on each of the multiple first surfaces 305A to 305E to be diverged and reflected in the X direction and emitted from the light emitting section 304, so that even if the incident light incident on each of the multiple first surfaces 305A to 305E is a parallel beam, the virtual image distance can be made finite by the emitted light that is reflected on each of the multiple first surfaces 305A to 305E and emitted from the light emitting section 304.

[0046] In this embodiment, the shape of each of the multiple first surfaces 305A-305E is formed into a curved shape that is a curved shape in a cross section parallel to the XZ plane, but as another embodiment, the shape of each of the multiple first surfaces 305A-305E may be formed into a polyhedral shape that is a shape formed by a plurality of straight lines in a cross section parallel to the XZ plane.

[0047] The radius of curvature of each of the plurality of first surfaces 305A-305E is greater than 800 mm and smaller than 10,000 mm. This allows the virtual image distance to be approximately 0.3-2 m by the divergent light reflected by each of the plurality of first surfaces 305A-305E and emitted from the light emitting part 304.

[0048] When the radius of curvature of each of the first surfaces 305A-305E exceeds the upper limit of 10,000 mm, the virtual image distance becomes almost infinite. On the other hand, when the radius of curvature of each of the first surfaces 305A-305E does not reach the lower limit of 800 mm, the virtual image distance becomes too close, making it difficult for the user to focus on the virtual image. In contrast, in this embodiment, the virtual image distance is finite, making it easy for the user to focus on the virtual image.

[0049] FIG. 6 is an explanatory diagram of a modified example of the image extraction portion 303 in the light guide member 300 according to the present embodiment.

[0050] FIG. 6(a) is an enlarged view of the image fetching unit 303 shown in FIGS. 4 and 5, and FIG. 6(b) is an enlarged view of the image fetching unit 303 according to a modified example.

[0051] 6(b), compared to FIG. 6(a), a third surface 307 is newly provided which is inclined in a direction different from that of the first surface 305. The third surface 307 is an example of a second inclined surface which is provided between the first surface 305 and the second surface 306 and is inclined so that the distance from the light ray emission unit 304 increases in the direction in which the image light is guided.

[0052] The light indicated by the solid and dotted lines in Figures 6(a) and 6(b) is light emitted from the same pixel of the image display element 100, and propagates through the light-guiding member 300 at the same angle due to the optical system 200 having a collimating optical system function.

[0053] In this case, the light indicated by the dotted line in Figure 6(a) is reflected by the second surface 306, then hits the first surface 305 directly and travels in the direction of the light ray emission section 304, whereas in Figure 6(b) the provision of the third surface 307 makes it possible to prevent the light from hitting the first surface 305 directly after being reflected by the second surface 306.

[0054] As a result, of the light propagating through the light-guiding member 300 by total reflection, only the light totally reflected by the lower surface of the light-guiding member 300 can be directed to the first surface 305 .

[0055] By doing so, in the modified example shown in Fig. 6(b), the difficulty of molding increases in order to form the third surface 307. However, it is possible to prevent stray light that occurs when light in both directions, which is totally reflected by the upper and lower surfaces of the light-guiding member 300, hits the first surface 305 in Fig. 6(a).

[0056] FIG. 7 is an explanatory diagram of a second modified example of the image extraction portion 303 in the light guide member 300 according to the present embodiment.

[0057] FIG. 7(a) is a detailed explanatory diagram of the image retrieval unit 303 relating to the modified example shown in FIG. 6(b), and FIG. 7(b) is a detailed explanatory diagram of the image retrieval unit 303 relating to the second modified example.

[0058] In the image extraction section 303 of the modified example shown in Figure 7(a), the second surface 306A, the third surface 307A, the first surface 305A, the second surface 306B, the third surface 307B, the first surface 305B, and the second surface 306C are arranged in order in the direction in which the image light is guided.

[0059] On the other hand, in the image extraction section 303 of the second modified example shown in Figure 7(b), the second surface 306A, the first surface 305A, the third surface 307A, the second surface 306B, the first surface 305B, the third surface 307B, and the second surface 306C are arranged in order in the direction in which the image light is guided.

[0060] In the image extraction section 303 of the modified example shown in Figure 7(a), the second surface 306B, the third surface 307B, and the first surface 305B, which are arranged on the downstream side in the direction in which the image light is guided, are arranged closer to the light beam emission section 304 than the second surface 306A, the third surface 307A, and the first surface 305A, which are arranged on the upstream side in the direction in which the image light is guided.

[0061] On the other hand, in the image extraction section 303 of the second modified example shown in Figure 7 (b), the second surface 306B, the first surface 305B, and the third surface 307B, which are arranged on the downstream side in the direction in which the image light is guided, and the second surface 306A, the first surface 305A, and the third surface 307A, which are arranged on the upstream side in the direction in which the image light is guided, are at the same distance from the light beam emission section 304.

[0062] The light guide member 300 according to the second modified example shown in FIG. 7(b) is heavier than the light guide member 300 according to the modified example shown in FIG. 7(a), but is easier to mold.

[0063] FIG. 8 is an explanatory diagram of a third modified example of the image extraction portion 303 in the light guide member 300 according to the present embodiment.

[0064] In the image extraction section 303 of the third modified example shown in Figure 8, similar to the image extraction section 303 of the modified example shown in Figure 7(a), the second surface 306A, the first surface 305A, the third surface 307A, the second surface 306B, the first surface 305B, the third surface 307B, and the second surface 306C are arranged in order in the direction in which the image light is guided.

[0065] In the image extraction section 303 of the modified example shown in Figure 7(a), the second surface 306B, the third surface 307B, and the first surface 305B, which are arranged on the downstream side in the direction in which the image light is guided, are arranged closer to the light beam emission section 304 than the second surface 306A, the third surface 307A, and the first surface 305A, which are arranged on the upstream side in the direction in which the image light is guided.

[0066] On the other hand, in the image extraction section 303 of the third modified example shown in Figure 8, the second surface 306B, the third surface 307B, and the first surface 305B, which are arranged on the downstream side in the direction in which the image light is guided, and the second surface 306A, the third surface 307A, and the first surface 305A, which are arranged on the upstream side in the direction in which the image light is guided, are at the same distance from the light beam emission section 304.

[0067] The light guide member 300 according to the third modified example shown in FIG. 8 is also heavier than the light guide member 300 according to the modified example shown in FIG. 7(a), but is easier to mold.

[0068] FIG. 9 is an explanatory diagram of a fourth modified example of the image extraction portion 303 in the light guide member 300 according to the present embodiment.

[0069] In the image extraction section 303 of the fourth modified example shown in FIG. 9, the second surface 306 is not arranged, and the third surface 307A, the first surface 305A, the third surface 307B, the first surface 305B, the third surface 307C, and the first surface 305C are arranged in that order in the direction in which the image light is guided.

[0070] In the light guide member 300 according to the fourth modification shown in FIG. 9, the eye box and the angle of view are small, but the unevenness in the intensity of the light beam incident on the eye at each angle of view is small.

[0071] Fig. 10 is an explanatory diagram of parameters of the light guiding member 300 according to this embodiment. Fig. 11 is an explanatory diagram of parameters of the image extraction unit 303 in the light guiding member 300 according to this embodiment.

[0072] ■Performance Eye box: 2.5mm or more Eye relief: 15mm Diagonal angle: 40 degrees Virtual image distance: 300mm

[0073] A plane-parallel member 310 is joined to the light-guiding member 300, and the interface between the light-guiding member 300 and the member 310 is made of a half mirror. ■ Part 310 Thickness: 0.6mm ■ Light guiding member 300 ·Wall thickness WD: thickest part 2.5mm ·Light guide member width ww: 50mm Width of the first surface 305: 0.2 mm Number of pages 305 on page 1: 24 Width of second surface 306: 0.6mm Refractive index: 1.493612 (PMMA) ·Reflection surface curvature radius R: 800mm The angles of the 24 first surfaces 305 relative to the second surfaces 306 were set as shown in Table 1.

[0074] [Table 1]

[0075] The number num of the multiple first surfaces 305 is within the range of 10 to 25. If the number exceeds the upper limit of 25, the first surfaces 305 become an obstacle when looking outside through the light guiding member 300. If the number is less than the lower limit of 10, the eye box in the horizontal direction becomes narrow and the viewing angle also becomes narrow. In this embodiment, the eye box in the horizontal direction becomes wide and the viewing angle also becomes wide, while making it easier to view outside through the light guiding member 300.

[0076] The distance W connecting both ends of the opposing surface in the direction in which the plurality of first surfaces 305A to 305D are arranged is longer than 0.1 mm and shorter than 3 mm, thereby ensuring an eyebox while providing a wide angle of view.

[0077] If the size of the eye is 3 mm, and the upper limit of 3 mm is exceeded, light with an angle of view that does not reach the eye occurs, and if the lower limit of 0.1 mm is not met, the width of the plane becomes too small, making it difficult to enlarge the eye box while maintaining a wide angle of view. In this embodiment, it is possible to enlarge the eye box while maintaining a wide angle of view, while ensuring the amount of light.

[0078] A distance 1 connecting both ends of first surface 305B in the direction in which first surfaces 305A to 305D are arranged is longer than 0.1 mm and shorter than 1 mm.

[0079] If the distance exceeds the upper limit of 1 mm, the first surface 305 becomes an obstacle when viewing the outside through the light-guiding member 300. If the distance is below the lower limit of 0.1 mm, the resolution is reduced due to the diffraction limit. In this embodiment, it is possible to increase the resolution while making it easier to view the outside through the light-guiding member 300.

[0080] FIG. 12 is a diagram showing the layout of an optical system of the virtual image display device 1000 according to the present embodiment. 12 creates an intermediate image of the light emitted from the image display element 100, generates approximately collimated light, and causes the light to enter the light guiding member 300. By creating an intermediate image once in this manner, the heavy image display element 100 can be disposed at the rear, so that when the virtual image display device 1000 is made into a glasses-type device, the weight at the front can be reduced, and a glasses-type virtual image display device that is comfortable to wear can be realized.

[0081] Of course, instead of creating an intermediate image, light may be made incident directly on the light-guiding member 300 by the optical system 200 that generates approximately collimated light from the image display element 100 as shown in Fig. 1. The light-guiding member 300 in Fig. 12 has the shape shown in Fig. 10, and is formed by joining plane-parallel members 310. Fig. 12 shows how light emitted from both ends of the image display element 100 enters the light-guiding member 300 via the optical system 200 and then enters the eye.

[0082] FIG. 13 is an explanatory diagram of a spot diagram in the virtual image display 1000 according to the present embodiment.

[0083] As shown in FIG. 13, the positions at which the spot diagram was calculated are point A (0,0), point B (2.3,0), point C (-2.3,0), point D (0,1.5), and point E (0,-1.5).

[0084] 14 to 18 are diagrams illustrating simulated spot diagrams at points A to E of the virtual image display 1000 according to this embodiment.

[0085] FIG. 19 is a diagram showing various examples of usage states of the virtual image display device 1000 according to this embodiment. 19(a), (b), and (c) illustrate a case in which the light guide member 300 is applied to a glasses-type virtual image display device, that is, an HMD.

[0086] 19(a) shows an example in which one light guiding member 300 is applied to a binocular HMD, and a light ray incident portion 301 of the light guiding member 300 and a mirror 350 that guides the image light incident from the light ray incident portion 301 into the light guiding member 300 are disposed on the right side of a virtual image observer, i.e., a user. The light guiding member 300 is fixed to a frame portion 500 that serves as a temple to be hung on the user's ear. Although the frame portion is shown in a simplified manner in FIG. 26, the frame portion 500 can be shaped to cover not only both ends of the light guiding member 300 but also the upper edge and the lower edge.

[0087] On the other hand, the examples shown in Fig. 19(b) and (c) are cases where one light guiding member 300 is miniaturized and applied to an HMD. The example shown in Fig. 19(b) is a case where two light guiding members 300 are arranged corresponding to the positions of the left and right eyes of a user as a binocular HMD, and the light entrance portion 8 of each light guiding member 300 is arranged on the left and right outer sides. Also, Fig. 19(c) is a case where one light guiding member 300 is arranged corresponding to the position of either the left or right eye of a user as a monocular HMD.

[0088] Although the virtual image optical system and the light source are not shown in Fig. 19, they can be attached to the frame unit 500. That is, in the examples shown in Fig. 19(a) and (c), the light source 52, the image display element 100, and the optical system 200 can be attached to the frame unit on the right eye side, and in the example shown in Fig. 19(b), they can be attached to both the left and right frame units.

[0089] 19, the light guiding member 300 is applied to a glasses-type HMD. The light guiding member 300 of each of the above-described embodiments can be applied to other types of HMDs, and can also be applied to a head-up display (HUD). The light guiding member of each of the embodiments is particularly suitable for displaying a virtual image of an original image formed by a light beam optically modulated by a microdevice.

[0090] As described above, the light guiding member 300 can be made to be worn on a person's face like glasses. When image light from an image display element or the like is collimated and incident from the light ray incident portion 301, an image from the image display element or the like can be observed as a virtual image, as described above. Since the light guiding member 300 is a transparent body, the surrounding scenery can be observed together with the image.

[0091] Light guide member 300 has a thickness of about 1 mm to 4 mm and is desirably made of a resin material, and such a configuration makes it sufficiently light, reduces the burden on the user's nose, and is easy to use.

[0092] ●Summary● As described above, the light-guiding member 300 according to one embodiment of the present invention comprises a light ray emission section 304 which is an example of an interface (boundary surface) that emits guided image light to the outside, and a first surface 305 which is an example of a reflecting surface that reflects the image light towards the light ray emission section 304 and emits it from the light ray emission section 304, and a plurality of first surfaces 305 are arranged in the direction in which the image light is guided, and among the plurality of first surfaces 305, downstream first surface 305F which is arranged on the downstream side in the direction in which the image light is guided is inclined in a direction in which the distance from the light ray emission section 304 increases downstream in the direction in which the image light is guided, relative to upstream first surfaces 305B, 305D which are arranged on the upstream side in the direction in which the image light is guided.

[0093] This makes it possible to make the angle between the emitted light reflected by the upstream first surfaces 305B, 305D and emitted from the light beam emission section 304, and the emitted light reflected by the downstream first surface 305F and emitted from the light beam emission section 304, larger than the angle between the incident light incident on the upstream first surfaces 305B, 305D, and the incident light incident on the downstream first surface 305F.

[0094] Each of the downstream first surfaces 305B to 305E is formed so that the further downstream it is positioned in the direction in which the image light is guided relative to the upstream first surface 305A, the greater the inclination angle in the direction in which the image light is guided and the greater the distance from the light emitting section 304 downstream in the direction in which the image light is guided.

[0095] As another embodiment, the inclination angles of the first surfaces 305A to 305E do not all need to be different. For example, the first surface 305C disposed between the first surfaces 305B and 305D may be formed so as to be parallel to either one of the first surfaces 305B and 305D.

[0096] Furthermore, when the incident light incident on upstream first surface 305B, 305D and the incident light incident on downstream first surface 305F are parallel, problems such as color shift caused by guiding non-parallel incident light can be avoided by light-guiding member 300, and the emitted light reflected on upstream first surface 305B, 305D and emitted from light beam emission section 304, and the emitted light reflected on downstream first surface 305F and emitted from light beam emission section 304 can be made into divergent light.

[0097] The downstream first surface 305F is inclined in a direction that increases the distance from the light beam emission section 304 on the downstream side in the direction in which the image light is guided, relative to the upstream first surface 305E arranged adjacent to it on the upstream side in the direction in which the image light is guided.

[0098] This makes it possible to make the angle formed by the respective emitted lights reflected at the adjacent upstream first surface 305E and downstream first surface 305F and emitted from the light beam emitting section 304 larger than the angle formed by the respective incident lights incident on the upstream first surface 305E and downstream first surface 305F.

[0099] The angle at which the downstream first surface 305F is inclined relative to the upstream first surface 305E is greater than 0.002 degrees and smaller than 0.210 degrees.

[0100] As a result, when a virtual image is formed by two emitted lights reflected by adjacent upstream first surface 305E and downstream first surface 305F, respectively, and emitted from light beam emitting section 304, the virtual image distance can be set to approximately 0.3 to 2 m.

[0101] If the angle at which the downstream first surface 305F is inclined relative to the upstream first surface 305E exceeds the upper limit of 0.210 degrees, the virtual image distance becomes too close, making it difficult for the user to focus on the virtual image. On the other hand, if the angle at which the downstream first surface 305F is inclined relative to the upstream first surface 305E is less than the lower limit of 0.002 degrees, the virtual image distance becomes almost infinite. In contrast, in this embodiment, the virtual image distance is kept finite, making it easy for the user to focus on the virtual image.

[0102] Each of the first surfaces 305A to 305E is formed in a convex shape. As an example, the shape of each of the first surfaces 305A to 305E in a cross section parallel to the light emitting unit 304 (XZ plane) is formed in a convex shape on the upstream side of the light guiding direction of the image light in the Z direction, which is the light guiding direction of the image light.

[0103] As a result, incident light incident on each of the multiple first surfaces 305A to 305E can be diverged in the X direction, for example, and emitted from the light emitting unit 304. When a virtual image is formed for each of the multiple first surfaces 305A to 305E by the emitted light reflected by each of the multiple first surfaces 305A to 305E and emitted from the light emitting unit 304, the virtual image distance can be made finite.

[0104] Each of the first surfaces 305A to 305E is formed in a curved shape. As an example, each of the first surfaces 305A to 305E is formed in a curved shape that is a curved shape in a cross section parallel to the XZ plane. As another embodiment, each of the first surfaces 305A to 305E may be formed in a polyhedral shape that is a shape formed by a plurality of straight lines in a cross section parallel to the XZ plane.

[0105] The radius of curvature of each of the plurality of first surfaces 305A to 305E is greater than 800 mm and smaller than 10,000 mm.

[0106] As a result, when a virtual image is formed for each of the first surfaces 305A-305E by divergent light that is reflected by each of the first surfaces 305A-305E and emitted from the light emitting portion 304, the virtual image distance can be set to approximately 0.3-2 m.

[0107] When the radius of curvature of each of the first surfaces 305A-305E exceeds the upper limit of 10,000 mm, the virtual image distance becomes almost infinite. On the other hand, when the radius of curvature of each of the first surfaces 305A-305E does not reach the lower limit of 800 mm, the virtual image distance becomes too close, making it difficult for the user to focus on the virtual image. In contrast, in this embodiment, the virtual image distance is finite, making it easy for the user to focus on the virtual image.

[0108] A second surface 306F facing parallel to the light emitting portion 304 is provided between two adjacent first surfaces 305E, 305F.

[0109] As a result, when a virtual image is formed by two divergent lights reflected by the two first surfaces 305E and 305F and emitted from the light emitting part 304, the pupil can be enlarged and an eye box can be secured while maintaining a wide angle of view. Also, more light can reach the first surface 305 on the back side of the light guiding member 300.

[0110] The distance W connecting both ends of the opposing surface in the direction in which the plurality of first surfaces 305A to 305D are arranged is longer than 0.1 mm and shorter than 3 mm, thereby ensuring an eyebox while providing a wide angle of view.

[0111] If the size of the eye is 3 mm, and the upper limit of 3 mm is exceeded, light with an angle of view that does not reach the eye occurs, and if the lower limit of 0.1 mm is not met, the width of the plane becomes too small, making it difficult to enlarge the eye box while maintaining a wide angle of view. In contrast, in this embodiment, it is possible to enlarge the eye box while maintaining a wide angle of view, while ensuring the amount of light.

[0112] A distance 1 connecting both ends of first surface 305B in the direction in which first surfaces 305A to 305D are arranged is longer than 0.1 mm and shorter than 1 mm.

[0113] If the distance exceeds the upper limit of 1 mm, the first surface 305 becomes an obstacle when viewing the outside through the light-guiding member 300. If the distance is below the lower limit of 0.1 mm, the resolution is reduced due to the diffraction limit. In contrast, in this embodiment, the resolution can be increased while making it easier to view the outside through the light-guiding member 300.

[0114] The number num of the multiple first surfaces 305 is within the range of 10 to 25. If the number exceeds the upper limit of 25, the first surfaces 305 become an obstacle when looking outside through the light guiding member 300. If the number is less than the lower limit of 10, the eye box in the horizontal direction becomes narrow and the viewing angle also becomes narrow. In contrast, in this embodiment, the eye box in the horizontal direction becomes wide and the viewing angle also becomes wide, while making it easier to see outside through the light guiding member 300.

[0115] The incident light incident on the downstream-side first surface 305 is approximately parallel to the incident light incident on the upstream-side first surface 305. This allows the parallel light incident on the upstream-side first surface 305 and the downstream-side first surface 305 to be emitted as divergent light.

[0116] A virtual image display device 1000, which is an example of a display device according to one embodiment of the present invention, includes a light-guiding member 300, an image display element 100 that emits image light, and an optical system 200 that is an example of an incident optical system that makes the image light enter the light-guiding member. The light-guiding member 300 includes a light ray emitting section 304 that emits the guided image light to the outside, and a first surface 305 that reflects the image light toward the light ray emitting section 304 and emits it from the light ray emitting section 304. A plurality of the first surfaces 305 are arranged in the direction in which the image light is guided. Of the plurality of first surfaces 305, a downstream first surface 305F that is arranged on the downstream side in the direction in which the image light is guided is inclined in a direction in which the distance from the light ray emitting section 304 to the downstream side in the direction in which the image light is guided increases, relative to upstream first surfaces 305B, 305D that are arranged on the upstream side in the direction in which the image light is guided.

[0117] As a result, the light-guiding member 300 can shorten the virtual image distance by making the angle between the emitted light reflected from the upstream first surfaces 305B, 305D and emitted from the light beam emission section 304, and the emitted light reflected from the downstream first surface 305F and emitted from the light beam emission section 304 larger than the angle between the incident light incident on the upstream first surfaces 305B, 305D, and the incident light incident on the downstream first surface 305F.

[0118] Furthermore, when the incident light entering the light-guiding member 300 from the optical system 200 is parallel, problems such as pixel shift, in which a double virtual image is observed, do not occur due to guiding non-parallel incident light, and the light-guiding member 300 makes the emitted light reflected at the upstream first surfaces 305B, 305D and emitted from the light ray emission section 304, and the emitted light reflected at the downstream first surface 305F and emitted from the light ray emission section 304, into diverging light, thereby making it possible to make the virtual image distance finite. [Explanation of symbols]

[0119] 100 Image display element 200 Input optical system (optical system) 201 Light propagating at the minimum reflection angle θ1 with respect to the light ray exit portion 304 202 Light propagating at the maximum reflection angle θ2 with respect to the light ray exit portion 304 300 Light guiding member 301 Ray entrance part 302 Light guide section 303 Image Extraction Unit 304 Light emission part (interface, boundary surface) 305 1st surface (reflecting surface, 1st inclined surface) 306 2nd surface (opposing surface) 307 3rd surface (2nd inclined surface) 310 Parallel Plane Members 1000 Virtual image display device (display device)

Claims

1. an interface that outputs the guided image light to the outside; a reflecting surface that reflects the image light toward the interface and emits the image light from the interface; Equipped with When an XYZ orthogonal coordinate system is defined in which the direction in which the image light is guided is a Z direction, the direction perpendicular to the Z direction and perpendicular to the interface is a Y direction, and the direction perpendicular to the Z direction and parallel to the interface is an X direction, The reflection surface is arranged in a plurality of directions in a Z direction in which the image light is guided, In a cross section parallel to the Y-Z plane of the XYZ orthogonal coordinate system, when comparing the inclination of a downstream reflective surface, among the multiple reflective surfaces, that is located downstream in the Z direction in which the image light is guided, with the inclination of an upstream reflective surface, which is located upstream in the Z direction in which the image light is guided, the inclination of the downstream reflective surface is inclined toward the interface in the Z direction at an angle closer to parallel to the interface than the inclination of the upstream reflective surface.

2. The light-guiding member according to claim 1 , wherein the downstream reflecting surface is inclined at an angle closer to being parallel to the interface than the upstream reflecting surface adjacent thereto on the upstream side in the Z direction in which the image light is guided.

3. 3. The light-guiding member according to claim 2, wherein an inclination angle of the downstream reflective surface with respect to the upstream reflective surface is greater than 0.002 degrees and smaller than 0.210 degrees.

4. A light-guiding member described in any of claims 1 to 3, wherein, in a cross section parallel to the X-Z plane of the XYZ orthogonal coordinate system, each of the multiple reflective surfaces is formed in a convex shape on the upstream side in the Z direction in which the image light is guided.

5. The light guide member according to claim 4 , wherein each of the plurality of reflecting surfaces is formed into a curved shape.

6. The light-guiding member according to claim 5 , wherein each of the plurality of reflecting surfaces has a radius of curvature greater than 800 mm and smaller than 10,000 mm.

7. 7. The light guide member according to claim 1, further comprising an opposing surface between two adjacent reflecting surfaces, the opposing surface being parallel to the interface.

8. The light-guiding member according to claim 7 , wherein a distance between both ends of the opposing surface in the Z direction in which the plurality of reflecting surfaces are arranged is longer than 0.1 mm and shorter than 3 mm.

9. 9. The light-guiding member according to claim 1, wherein a distance between both ends of the reflecting surfaces in the Z direction in which the reflecting surfaces are arranged is longer than 0.1 mm and shorter than 1 mm.

10. 10. The light-guiding member according to claim 1, wherein the number of the plurality of reflective surfaces is in the range of 10 to 25.

11. 11. The light guide member according to claim 1, wherein the incident light incident on the downstream reflecting surface and the incident light incident on the upstream reflecting surface are substantially parallel to each other.

12. A light guiding member according to any one of claims 1 to 10; an image display element that emits the image light; an incident optical system that causes the image light to be incident on the light-guiding member.

Images