Angle-selective transmission element and display device

Abstract

To provide an angle selection type transmission element capable of eyepiece observation without vignetting in a peripheral portion while reducing a ghost caused by external light.SOLUTION: An HMD (head mounted display) 1 is equipped with an electronic viewfinder 3. An angle selection type transmission element 6 is arranged in an optical path of the electronic viewfinder 3. The angle selection type transmission element 6 is provided at a position facing an eye point 13 and has a plurality of openings 6c as limiting means for limiting the passing direction of light to a predetermined range. In the angle selection type transmission element 6, the limiting angle ranges of the light passing direction are different in at least two regions, and it is possible to limit or block light from a direction other than the eye point.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a ghost reduction technique for head mounted displays, binoculars, camera viewfinders, and the like, and more particularly to an angle-selection type transmission element attached to a viewfinder. [Background technology]

[0002] When a user uses a head mounted display or a camera viewfinder outdoors, there is a possibility that ghost images may be generated by light coming from behind the user. In order to reduce unnecessary light caused by external light, Patent Document 1 discloses a technology for cutting out the light that causes ghost images by placing a louver film on the eye side of the display unit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 5-215908 Summary of the Invention [Problem to be solved by the invention]

[0004] The conventional technology disclosed in Patent Document 1 blocks light in the light-shielding direction of a louver film placed on the display. Therefore, this method cannot be applied to applications where the user brings their eye close to the display, such as viewfinders, because this causes vignetting on the periphery. An object of the present invention is to provide an angle-selective transmission element that enables ocular observation without vignetting at the periphery while reducing ghosts caused by external light. [Means for solving the problem]

[0005] An optical element according to an embodiment of the present invention is an angle-selective transmission element that is disposed in an optical path and has a plurality of apertures, The plurality of openings constituteThe optical fiber has a limiting means for limiting the direction in which a light beam passes, the portion of the limiting means through which the light beam passes is formed radially from a point that is three-dimensionally predetermined as a center, and the inside of the opening is filled with a substance whose refractive index differs from that of air by 0.1 or less. Effect of the Invention

[0006] According to the present invention, it is possible to provide an angle-selective transmission element that enables ocular observation without vignetting at the periphery while reducing ghosts caused by external light. [Brief description of the drawings]

[0007] [Figure 1] 1 is an external view of a display device (head mounted display) to which the present invention is applied. [Diagram 2] FIG. 2 is a diagram showing a state in which a user wears the display device on his / her head. [Diagram 3] 3 is a diagram showing a state in which the display unit is flipped up from the state shown in FIG. 2. FIG. [Figure 4] FIG. 2 is a cross-sectional view showing a configuration of the display device during use. [Diagram 5] FIG. 3 is a cross-sectional view taken along line AA in FIG. 2. [Figure 6] FIG. 6 is a detailed view showing part B in FIG. 5. [Figure 7] 2 is a diagram showing a first surface side of an angle-selective transmission element. FIG. [Figure 8] 13 is a diagram showing a second surface side of the angle-selective transmission element. FIG. [Figure 9] FIG. 8 is a detailed view showing part C in FIG. [Figure 10] FIG. 8 is a cross-sectional view taken along line DD in FIG. [Figure 11] FIG. 9 is a detailed view showing part E in FIG. 8. [Figure 12] 1A and 1B are diagrams illustrating examples of the shape of an opening portion provided in an angle-selective transmission element. [Figure 13] 13 is a diagram showing a second surface side of an angle-selective transmission element according to a modified example. FIG. [Figure 14]FIG. 6 is a cross-sectional view showing an optical path different from that in FIG. 5 in a modified example. [Figure 15] 15 is a detailed view showing part G in FIG. 14. [Figure 16] 13A and 13B are detailed diagrams illustrating an angle-selective transmission element according to a modified example. [Figure 17] FIG. 6 is a cross-sectional view showing an optical path different from that in FIG. 5 in a modified example. [Figure 18] FIG. 18 is a detailed view showing part H in FIG. [Figure 19] FIG. 11 is an external view illustrating a second embodiment of the present invention. [Figure 20] FIG. 20 is an exploded perspective view showing the configuration of the angle-selective transmission element of FIG. 19. [Figure 21] FIG. 2 is a detailed view showing the wall of the angle-selective transmission element with metal plates laminated thereon. [Figure 22] 1 is a diagram illustrating the relationship between an opening of an angle-selective transmission element and an eye point. [Figure 23] 23 is a diagram for explaining the relationship between the state in which the eye point position is moved and the amount of aperture enlargement in comparison with FIG. 22. FIG. [Figure 24] FIG. 11 is a configuration diagram for explaining a third embodiment of the present invention. [Diagram 25] FIG. 25 is a plan view showing an example of the arrangement of the film in FIG. 24. [Figure 26] FIG. 13 is an external view illustrating a fourth embodiment of the present invention. [Figure 27] FIG. 27 is a partial cross-sectional view of the angle-selective transmission element of FIG. 26. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. A head mounted display (hereinafter, referred to as HMD) is shown as an example of a display device that uses an angle-selective transmission element arranged in the optical path of a finder, etc. However, the present invention is not limited to this, and can be applied to various optical devices.

[0009] [First Example] An angle-selective transmission element according to a first embodiment of the present invention will be described with reference to Fig. 1 to Fig. 11. Fig. 1 is an external view showing a configuration example of an HMD 1. The HMD 1 comprises a main body 2, electronic viewfinders (hereinafter referred to as EVFs) 3 and 4, and a head-mounted unit 5. The pair of EVFs comprises an EVF 3 for the left eye and an EVF 4 for the right eye.

[0010] The main body 2 and head mounted unit 5 of the HMD 1 are rotatably connected by a hinge 2a on the main body 2 and a hinge 5a on the head mounted unit 5. The left eye EVF 3 and right eye EVF 4 are held relative to the main body 2 in a state in which their interpupillary distance can be adjusted.

[0011] Figures 2 and 3 show a state in which a user wears the HMD 1 on his / her head. Figure 2 shows a state in which the user is looking at the display screen, and Figure 3 shows a state in which the main body 2 of the HMD 1 is flipped up so that the user can see the surroundings.

[0012] Angle-selective transmission elements 6 and 7 are attached to the portions where the user looks into the EVF 3 and EVF 4, respectively. The angle-selective transmission element 6 and the angle-selective transmission element 7 in this embodiment have the same configuration, but by making the configurations of both elements different, it is possible to optimize the convergence angle between the right eye and the left eye and the ghost cutting characteristics.

[0013] 4 is a cross-sectional view showing the configuration of the main body 2 and EVF 3 when the HMD 1 is in use, showing the portion corresponding to the left eye of the user. The display unit 9 and eyepiece lens system 10 are provided inside the exterior member 11 of the EVF 3. The display unit 9 has an organic EL (Electro-Luminescence) display panel. The surface of the eyepiece lens system 10 facing the angle-selective transmission element 6 is flat. The angle-selective transmission element 6 is disposed in a position facing the left eye of the user on the exterior member 11. The first surface 6a of the angle-selective transmission element 6 is the surface facing the user's eye, and the second surface 6b is the surface facing the eyepiece lens system 10.

[0014] The angle-selective transmission element 6 is provided with a plurality of openings 6c, and has the function of restricting the light passing direction. The plurality of openings 6c constitute a restricting means for restricting the passing direction of the light beam in the angle-selective transmission element arranged in the optical path. The light beam passing portion is formed three-dimensionally (spatially) radially from a predetermined point. The predetermined point is a point on the optical axis away from the angle-selective transmission element 6. For example, the plurality of openings 6c are opened in the direction of the light beam going from the eyepiece lens system 10 to the position of the eye point 13, which is the position of the user's eye. FIG. 4 shows a schematic diagram of the finder light beam 12 that reaches the eye point 13 out of the light beams emitted from the eyepiece lens system 10. The position of the eye point 13 is determined by the eyepiece lens system 10.

[0015] The exterior member 14 of the main body 2 has therein a control circuit 15 that controls the entire HMD 1. The control circuit 15 controls the display unit 9, and light from the display unit 9 is collected by the eyepiece lens system 10 and passes through a plurality of openings 6c provided in the angle-selective transmission element 6, so that the information displayed on the display unit 9 is observed by the eye at the position of the eyepoint 13.

[0016] Fig. 5 is a cross-sectional view taken along line AA in Fig. 2, showing the relationship between the head and eyeballs of the HMD 1 and the HMD 1 when the HMD 1 is in use. Fig. 6 is a detailed view showing an enlarged view of part B in Fig. 5. Part B in Fig. 5 shows a portion facing the left eye of the user. As shown in Fig. 6, the multiple openings 6c inside the angle-selective transmission element 6 are formed between multiple adjacent wall portions 6d. In other words, two adjacent openings 6c are separated by the wall portion 6d.

[0017] In this embodiment, the inside of the multiple openings 6c is filled with a transparent solid having a small refractive index difference with air. By filling the inside of the angle-selective transmission element 6 with a transparent solid having a small refractive index difference with air, it is possible to prevent dust from entering the multiple openings 6c. In addition, it is possible to prevent the wall portion 6d from being deformed by an external force. In this embodiment, a porous transparent material containing 90% or more of air is used as the transparent solid having a small refractive index difference with air, and the refractive index difference with air is 0.1 or less. Therefore, there is almost no reflection at the boundary surface with air. Inside the multiple openings 6c, there is almost no reflection at the transparent solid surface having a small refractive index difference with air on both the first surface 6a on the eye side and the second surface 6b on the eyepiece lens system 10 side, and light entering the multiple openings 6c from the outside enters the inside with almost no reflection.

[0018] Anti-reflection treatment is applied to the first surface 6a, the second surface 6b, and the inner surfaces of the multiple openings 6c (the inner surfaces of the wall portions 6d) of the angle-selective transmission element 6. The angle-selective transmission element 6 can be produced using a 3D printer, and the anti-reflection treatment can be achieved by applying an anti-reflection coating.

[0019] When using the HMD1 shown in Fig. 5, assume that the light is completely in front of the user, that is, the light is coming from a direction in which the user faces away from the light source (such as the sun). In this case, most of the light that enters the angle-selective transmission element 6 and the eyepiece lens system 10 is blocked by the user's head. However, when the user rotates his or her face from this state to the side by an angle of several tens of degrees, the light that passes through the side of the face (light that passes through the cross-hatched area in Fig. 5) reaches the position of the angle-selective transmission element 6 and the eyepiece lens system 10.

[0020] In the case of the left eye, the area where reverse light may cause ghosts in the eyepiece lens system 10 is the cross-hatched area in Fig. 5, as shown by the line 17 connecting the point 16 in Fig. 5 and the side of the head. In this embodiment, multiple openings 6c are provided from the eye point 13 toward the eyepiece lens system 10. In order for light to reach the eyepiece lens system 10 located on the side farther away from the multiple openings 6c than the user, a light source must be present in the direction of the hole of the openings 6c. Line 17 in Fig. 5 indicates the position where the direction of the multiple openings 6c and the direction of the light rays are closest, making it easier for reverse light to reach the eyepiece lens system 10.

[0021] In Fig. 6, light ray 18 represents light that has passed through the side of the user's head. Light ray 18 enters the inside through holes in the multiple openings 6c provided on the first surface 6a of the angle-selective transmission element 6. The light that enters the multiple openings 6c reaches the wall 6d, but the reflected light is attenuated because the wall 6d is anti-reflection treated. Therefore, even if the reflected light reaches the eyepiece lens system 10, almost no ghosting occurs.

[0022] The thickness of the angle-selective transmission element 6 is denoted as t, the opening width of the opening 6c is denoted as w, and the incident angle of the unwanted light is denoted as θ0. The condition for preventing the unwanted light from directly reaching the eyepiece lens system 10 is given by the following formula (1). t ≧ w / tan θ0(1) Tan represents a tangent function, and in this embodiment, the condition of formula (1) is satisfied.

[0023] Fig. 7 is a diagram showing a first surface 6a of the angle-selective transmission element 6. Fig. 8 is a diagram showing a second surface 6b of the angle-selective transmission element 6. Fig. 9 is a detailed enlarged view of part C in Fig. 7. Fig. 10 is a cross-sectional view taken along line DD in Fig. 7. Fig. 11 is a detailed enlarged view of part E in Fig. 8.

[0024] As shown in Fig. 7 to Fig. 9, the multiple openings 6c provided in the angle-selective transmission element 6 are formed in a hexagonal shape on the second surface 6b, which is the entrance side of the viewfinder light beams, and on the first surface 6a, which is the exit side of the viewfinder light beams. In this embodiment, all the hexagonal openings provided on the second surface 6b have the same shape within the second surface 6b. Also, all the hexagonal openings provided on the first surface 6a have the same shape within the first surface 6a. Also, adjacent hexagonal portions are separated by walls 6d, and the inside of the openings 6c is filled with a transparent solid having a small refractive index difference with air.

[0025] Fig. 10 (DD cross-sectional view of Fig. 7) shows the orientation of the multiple openings 6c. The orientation of the multiple openings 6c is set so as to follow the direction of light heading toward eyepoint 13. That is, the multiple openings 6c are formed three-dimensionally radially from eyepoint 13, which is a predetermined point, as the center. The distance between eyepoint 13 and the first surface 6a is denoted as E1, and the distance between eyepoint 13 and the second surface 6b is denoted as E2. The formation pitch of the multiple openings 6c on the first surface 6a is denoted as P1.

[0026] The multiple openings 6c are provided at equal pitches, and the distance from the optical axis center is represented as Hi. In the right half of FIG. 10 with the optical axis center as the reference, i in "Hi" represents any natural number from 1 to 9. H1=P1 H2=P1×2 · · H8=P1×8 H9=P1×9 In other words, the relationship is "Hi = P1 x i."

[0027] With respect to the center of the optical axis as a reference, the angle of each line connecting the eye point 13 and each of the openings 6c is represented as θi. The i in “θi” represents any natural number from 1 to 9. θ1=tan -1 (H1 / E1) θ2=tan -1 (H2 / E1) · · θ8=tan -1 (H8 / E1) θ9=tan -1 (H9 / E1) tan -1 represents the arctangent function, and "θi = tan -1 (Hi / E1)" relationship.

[0028] The pitch P2 of the multiple openings 6c on the second surface 6b is as shown in the following formula (2). P2 = E2 × tan θ1 (2) In FIG. 10, the right half surface has been described with reference to the center of the optical axis, but the same relationship as above also applies to the left half surface since the configuration is symmetrical with respect to the optical axis.

[0029] When the eyepiece lens system 10 is viewed from the user's eye with the position of the eye point 13 as a reference, the eyepiece lens system 10 is seen through the multiple openings 6c. The wall portion 6d is almost parallel to the direction of light reaching the user's eye, so it is almost invisible. When the user's eye is at the eye point 13, the first surface 6a is close to the eye and the focus is not achieved. The wall portion 6d is made thin, so the flat portion at the entrance of the wall portion 6d is almost invisible. In addition, as shown in Figures 9 and 11, in this embodiment, the thickness of the wall portion 6d between the openings is formed to be equal on the eye side and the lens side.

[0030] The user can only view the displayed information from the vicinity of eyepoint 13, and the position of the eyes must be fixed near eyepoint 13. In this embodiment, the head mounting unit 5 fixes the relative positional relationship between the user's head and HMD 1, thereby enabling the eyes to be placed at the position of eyepoint 13.

[0031] In this embodiment, the angle-selective transmission element 6 arranged in the optical path of the finder has a plurality of openings 6c that limit the passing direction of the light beam to a predetermined range. The angle range in which the passing direction of the finder light is limited is different in at least two regions (see FIG. 10). That is, a first angle (lens optical axis direction angle) that limits the passing direction of the finder light beam at a central position as a first region is different from a second angle (θ1) that limits the passing direction of the light beam at a peripheral position as a second region. The light passing direction limiting means is composed of a plurality of openings 6c that are radially arranged from the eye point 13 toward the eyepiece lens system 10. In addition, in this embodiment, ten kinds of light passing directions are provided, including eight regions θ2 to θ9. Therefore, it is possible to limit or block light from directions other than the eye point.

[0032] According to this embodiment, it is possible to provide an angle-selective transmission element that enables ocular observation without vignetting at the periphery while reducing ghosts caused by external light from behind the user.

[0033] [Modification of the first embodiment] A modified example of the first embodiment will be described with reference to Fig. 12 to Fig. 18. Fig. 12 is a diagram showing a schematic shape of the openings 6c provided on the first surface 6a and the second surface 6b of the angle-selective transmission element 6. Fig. 12(A) shows a case where the multiple openings 6c provided on the first surface 6a and the second surface 6b of the angle-selective transmission element 6 are formed in a regular hexagon, as described in the first embodiment. In this case, the opening ratio becomes the largest, and the structure has the highest flexibility (shock absorption capacity).

[0034] In the modified example, examples of the shape of the opening 6c will be described. In addition to the regular hexagon, regular polygons that can fill a plane with one type include the equilateral triangle shown in Fig. 12(B) and the regular quadrilateral (square) shown in Fig. 12(C). These three types of shapes are called regular plane tessellations. Among them, the equilateral triangle has the greatest strength, and the shape of the opening 6c can be selected depending on the application.

[0035] In addition, the multiple openings 6c provided on the first surface 6a and the second surface 6b of the angle-selective transmission element 6 can be composed of multiple regular polygons only. These are called Archimedean tessellations, which have uniform vertex shapes that can fill a plane, and there are eight types of shapes. Among them, there are two types that combine equilateral triangles and regular hexagons. Figures 12(D) and 12(E) show examples of combinations of equilateral triangles and regular hexagons. By using a configuration using multiple regular polygons, the angle-selective transmission element 6 can be created by combining the advantages of each shape. Other shapes that can be used for plane tessellation include polygonal plane tessellation, non-periodic tessellation, and tessellation with a center (spiral tessellation, radial tessellation, etc.). These can also be applied to the shape of the openings 6c depending on the application.

[0036] Fig. 13 shows a modified example having multiple regions with different apertures. Fig. 13(A) shows the second surface 6b of the angle-selective transmission element 6, and Fig. 13(B) is a detailed view of part F in Fig. 13(A). This shows a configuration in which the aperture of the angle-selective transmission element 6 is partially modified. By mixing a portion 6c with a wide aperture and a portion 6f with a narrow aperture, it becomes easier to achieve both an improvement in the aperture ratio and a reduction in unnecessary light.

[0037] The light passing through the side of the user's head will be described with reference to Figs. 14 and 15. Fig. 14 is a cross-sectional view showing a different optical path from Fig. 5, and Fig. 15 is a detailed view of part G in Fig. 14. Light ray 55 in Fig. 14 and light rays 55a, 55b, and 55c in Fig. 15 represent light passing through the side of the user's head. Light that enters the inside of the multiple openings 6c is reflected by the wall 6d, but the number of reflections decreases as it approaches the center of the head. Therefore, if the reflected light is not sufficiently attenuated, the light that causes ghosts cannot be reduced uniformly.

[0038] A detailed view of the modified example is shown in Fig. 16. Fig. 16 shows the optical path when the opening 6f is located toward the center of the head. The opening of the opening 6f in the area toward the center of the user's eyes is narrower than the opening in the area away from the center of the eyes. In the modified example, the narrowing of the opening increases the number of times the light beam is reflected, making it easier to attenuate. In addition, the wide opening 6c is located in the center of the angle-selective transmission element 6, so the view through the eyepiece lens system 10 is not impaired.

[0039] Also, instead of narrowing the opening, there is a method of partially changing the material thickness of the angle-selective transmission element 6. The light passing through the side part of the user's head will be described with reference to Figs. 17 and 18. Fig. 17 is a cross-sectional view showing an optical path different from that of Fig. 5, and Fig. 18 is a detailed view of part H in Fig. 17. The light rays 55, 55a, 55b, and 55c are as described in Figs. 14 and 15. The tubular length of the opening in the area toward the center of the user's eyes is longer than the tubular length of the opening in the area away from the center of the eyes.

[0040] 17 and 18, the surface 6g on the entrance side of the finder light beam of the angle-selective transmission element 6 is formed in a curved shape that follows the curved surface of the eyepiece lens system 10. As the tube length of the opening 6c increases toward the center of the user's head, the number of reflections of the light beam increases, making it easier for the light beam to be attenuated.

[0041] [Second Example] Next, a second embodiment of the present invention will be described. In this embodiment, an example is shown in which an angle-selective transmission element is made of a laminated structure of metal plates. In this embodiment, detailed explanations of matters similar to those in the first embodiment will be omitted, and differences will be mainly explained. Such a method of omitting explanations will be the same in the embodiments described later.

[0042] Fig. 19 is an external view of an angle-selective transmission element 20 made by laminating multiple metal plates. The surface shown in the figure is the surface 20b on the eyepiece system side, and the opposite surface is the surface 20a on the eye side. The angle-selective transmission element 20 has multiple openings 20c, similar to the first embodiment.

[0043] 20 is an exploded perspective view of the angle-selective transmission element 20. The angle-selective transmission element 20 is composed of 19 aluminum plates 19. A plurality of openings 20c are provided in the aluminum plates 19 by forming circular holes by etching. The diameter of the circular holes is the same for the 19 aluminum plates, but the pitch is different.

[0044] Fig. 21(A) is a partial cross-sectional view showing a state where a plurality of aluminum plates 19 are stacked. The upper side of Fig. 21(A) is the eyepiece lens system side, and the lower side of Fig. 14 is the eye side. In the stacked state, the opening 20c faces the eyepoint position as in the first embodiment. The size of the opening diameter of the plurality of openings 20c provided in the aluminum plate 19 is different for each stacked aluminum plate, and the opening 20a on the eye side is the smallest, and the opening 20b on the eyepiece lens system side is the largest. In addition, the region that limits the passing direction of the light beam is formed by configuring the center position of the opening diameter of the openings 20c provided in the aluminum plate 19 to be different between the front and rear of the stacked aluminum plates.

[0045] In this embodiment, the opening diameters of the multiple openings 20c provided in one aluminum plate 19 are uniform, and the pitch differs for each stacked aluminum plate, so the width of the walls between the holes varies. After the metal plates are stacked, they are integrated by diffusion bonding, and then matte anodized to perform an anti-reflection treatment on the entire plate.

[0046] The plurality of openings 20c that limit the light beam passing direction are partitioned by wall portions 20d, and are composed of wall surfaces in at least two directions that are not parallel to the light beam passing direction.

[0047] In the detailed view of the wall of the angle-selective transmission element shown in Fig. 21(A), the wall 20d is composed of a wall surface 20d1 and a wall surface 20d2. Fig. 21(B) is a cross-sectional view of one aluminum plate 19 among a plurality of laminated aluminum plates. The opening 20c provided in the aluminum plate 19 may be provided with a sharp edge shape portion 20e. The attenuation of the reflected light can be increased by the sharp edge shape portion 20e provided in the aluminum plate 19 and the anti-reflection treatment applied to the wall 20d.

[0048] In this embodiment, glass (not shown) is placed on one side (eye side) of the angle-selective transmission element 20 to prevent dust from entering. In addition, anti-reflection coating is applied to both surfaces of the glass. According to this embodiment, an angle-selective transmission element that has the same effect as the previous embodiment can be realized by using a configuration in which multiple metal plates are stacked.

[0049] In order to realize a form in which the pitch of holes in metal plates stacked in the optical axis direction is different to match the optical path, the diameters of the multiple openings in one metal plate are made uniform and the intervals between the holes are made different. The advantages of this include the ease of processing the metal plate and the ease of blocking light that causes ghosts.

[0050] On the other hand, as another method for forming an aperture according to the optical path, the aperture diameters of the multiple apertures 20c are made different as described above. In this case, it is reasonable to make the aperture size larger for the metal plate closer to the eyepiece system and smaller for the metal plate closer to the eyepoint along the optical path where the light diffusing at the exit pupil of the eyepiece system forms an image at the eyepoint. In particular, it is desirable for the shape to be a cone with the eyepoint as its apex.

[0051] Fig. 22 is a schematic diagram showing the relationship between the opening of the angle-selective transmission element and the eyepoint. As described above, the openings of a plurality of metal plates are illustrated when the openings are provided as a cone with the eyepoint as the apex. Fig. 22 shows an optical axis 60, an eyepiece lens 61 closest to the eye, metal plates 62a-c for blocking light, and an eyepoint 63. The openings of the metal plates 62a-c are provided to have a cone shape with the eyepoint 63 as the apex, as shown by the dashed line.

[0052] However, in the configuration shown in Fig. 22, the eyebox, which is the viewing area in which an image can be seen properly, becomes small, and even a slight deviation of the eye position from the eyepoint may cause vignetting of the image. In such a situation, it is effective to enlarge the opening of the metal plate close to the eyepoint from a shape that follows the cone. By making the amount of enlargement of the opening from the cone larger for metal plates closer to the eyepoint, the effect of enlarging the eyebox can be expected. This is also true when metal plates (mask members) are arranged with a gap between them as in the fourth embodiment described later.

[0053] FIG. 23 is a diagram showing a state in which the position of the eye point has been moved with respect to FIG. 22. FIG. 23(A) is a diagram showing an example of an aperture enlargement area of ​​a metal plate close to the eye point for enlarging the eye box. FIG. 23(B) is an enlargement diagram showing the aperture enlargement area of ​​interest. Point 64 is a point corresponding to the eye point at the end of the eye box when the eye box is enlarged. As shown by the dashed line, the upper line of the display area is blocked by the aperture from the eye point position of point 64, and vignetting occurs in the image. Therefore, by enlarging the aperture in the parts corresponding to regions 65b and 65c, it is possible to suppress the occurrence of vignetting even from the eye point position of point 64, and to properly observe the image. As a result, the image can be properly observed not only at point 63 but also at point 64, so that the eye box can be enlarged.

[0054] The amount of aperture enlargement will be described with reference to FIG. 23(B). It is reasonable to enlarge the amount of aperture enlargement in proportion to the distance between the eyepiece and the mask member (metal plate). That is, the distances from the eyepiece surface to the metal plates 62b and 62c are denoted as db and dc, respectively. Using an appropriate proportionality coefficient k, the aperture is enlarged as "amount of aperture enlargement corresponding to region 65b = k x db" and "amount of aperture enlargement corresponding to region 65c = k x dc". This ensures an optical path connecting the image at the eyepiece position and the eye point (point 64) at the eye box edge position, and makes it possible to obtain a good image without vignetting even at the eye point position indicated by point 64. Note that, although FIG. 23 describes a configuration in which the amount of aperture enlargement is proportional to the distance from the eyepiece surface, this is not limiting. The openings of the openings that the multiple plates or mask members have on the eye point side may be enlarged relative to a line connecting the openings of the openings of the plate or mask member closest to the eyepiece system and the eye point. By removing the portions corresponding to the regions 65b and 65c in at least some of the openings of the three or more plates or mask members to widen the openings, it is possible to ensure a sufficient eye box.

[0055] [Third Example] A third embodiment of the present invention will be described with reference to Figures 24 and 25. The angle-selective transmission element of this embodiment is constructed using a plurality of types of louver films.

[0056] Figure 24 is a schematic diagram showing an example of an angle-selective transmission element realized by combining multiple types of louver films. The louver film has a structure in which plate-shaped opaque parts are regularly arranged inside a transparent film, and it is possible to control the direction in which light passes through.

[0057] As shown in Fig. 24, the louver film constituting the angle-selective transmission element of this embodiment is divided into multiple regions 33-35 centered around the viewfinder optical axis. The angle of light ray 30 parallel to the viewfinder optical axis, i.e., the first angle, is defined as zero. Light ray 31 represents light at a second angle that is inclined with respect to the viewfinder optical axis, and light ray 32 represents light at a third angle. The third angle is larger than the second angle.

[0058] In the example shown in Fig. 24, first region 33 has an opaque portion that is parallel to the viewfinder optical axis (first angle) and extends in the depth direction of Fig. 24 (direction perpendicular to the paper surface). Second region 34 has an opaque portion that is parallel to the second angle and extends in the depth direction of Fig. 24. Third region 35 has an opaque portion that is parallel to the third angle and extends in the depth direction of Fig. 24.

[0059] FIG. 25 is a diagram showing the planar arrangement of the configuration of FIG. 24, and is a schematic diagram when viewed from the direction along the viewfinder optical axis. In this embodiment, the film is arranged in eight regions divided in the rotation direction around the viewfinder optical axis. The shape of the first region 33 closest to the viewfinder optical axis is a substantially regular octagon, and the second region 34 adjacent to the outside of the first region 33 is composed of eight divided regions. Similarly, the third region 35 adjacent to the outside of the second region 34 is composed of eight divided regions. Each region shown in FIG. 25 is arranged rotationally symmetrically around the viewfinder optical axis. Note that the division method shown in this embodiment is an example, and the number of divisions, etc. can be set arbitrarily.

[0060] According to this embodiment, an angle-selective transmission element similar to that of the previous embodiment can be constructed by combining multiple types of louver films created by stacking opaque and transparent films and changing the direction in which light is cut.

[0061] [Fourth Example] A fourth embodiment of the present invention will be described with reference to Figures 26 and 27. In this embodiment, an example of an angle-selective transmission element having a structure in which a plurality of mask members (metal plates) are arranged at predetermined intervals will be shown.

[0062] Fig. 26 is a diagram showing a separated laminated angle selection type transmission element 40. The surface seen in Fig. 26 is the surface 40b on the eyepiece lens system side, and the opposite surface is the surface 40a on the eye side. The transmission element 40 is realized by intermittently arranging multiple metal plates described in the second embodiment.

[0063] FIG. 27 is a partial cross-sectional view of the transmission element 40. The transmission element 40 has a configuration in which a plurality of mask members and spacers (separation members) are overlapped. For example, a first spacer 50 is arranged on one surface side of a first mask 41. Next (upper side of FIG. 27), a second mask 42 is positioned, and a second spacer 51 is further arranged. Similarly, a third mask 43 and a third spacer 52, a fourth mask 44 and a fourth spacer 53, a fifth mask 45 and a fifth spacer 54 are arranged, and a sixth mask 46 is further arranged. In this manner, the first to fifth spacers are arranged between the first to sixth masks, respectively, to form gaps between the mask members.

[0064] In FIG. 27, the viewfinder optical axis 47 and the direction toward the eye point position (not shown) are indicated by a dashed line. The positions of the multiple openings of the transmission element 40 change depending on the distance from each layer indicated by the first mask 41 to the sixth mask 46 and the viewfinder optical axis 47. Taking an intermediate light beam indicated by a light ray 48 as an example, the openings 41a to 46a in FIG. 27 are arranged along the direction of the light beam. That is, the first mask 41 has an opening 41a, the second mask 42 has an opening 42a, the third mask 43 has an opening 43a, the fourth mask 44 has an opening 44a, the fifth mask 45 has an opening 45a, and the sixth mask 46 has an opening 46a. With the viewfinder optical axis 47 as a reference, the distance to the opening 41a is the shortest, and the distance to the opening 46a is the longest.

[0065] When there is a gap between adjacent mask members, there is a possibility that crosstalk light passing through the gap may reach the eyepiece lens system, which may cause ghosting. In this embodiment, measures are taken to reduce crosstalk light. An example of light that may cause ghosting is shown as a group of light rays 49 in FIG. 27. For example, light that passes through opening 41a of first mask 41 is blocked by connecting regions 42b, 43b, 44b, and 45b between the openings. Connecting regions 42b, 43b, 44b, and 45b are provided in second mask 42 to fifth mask 45, respectively, and the light blocking (or light reducing) function of each region prevents unnecessary light from reaching the eyepiece lens system.

[0066] Furthermore, with regard to this light blocking (or light reduction) function, the light reflected by the eyepiece lens surface may be blocked without blocking the incident light as shown by the group of rays 49 by the connecting regions 42b, 43b, 44b, 45b. In other words, even if the light path passing through the opening 41a reaches the eyepiece lens surface, the reflected light may be blocked by the connecting regions 42b, 43b, 44b, 45b before it exits from another opening. This allows for greater freedom in designing the connecting regions compared to a configuration in which light blocking or light reduction is performed only on the incident light path.

[0067] The transmission element 40 shown in this embodiment has glass (not shown) arranged on one side (the side facing the user's eye) to prevent dust from entering. The glass has an anti-reflection coating on both sides.

[0068] According to this embodiment, in a configuration having a plurality of gaps in which separating members are disposed between a plurality of mask members, an angle-selective transmission element that exhibits the same effects as the above-described embodiment can be realized.

[0069] The configuration described in the above embodiment can provide an optical element and an optical device that allows the user to observe the displayed information through the eyepiece while reducing ghosting caused by light coming from behind the user. In other words, even in applications (finders and HMDs) where the user's eyes are close to the optical system to within a few centimeters, the displayed information can be observed without causing peripheral vignetting. In addition, when using a finder using the angle-selective transmission element of the above embodiment, it is possible to ensure a sufficient field of view, and the user can grasp the surrounding situation. For example, in a method of attaching a rubber eyecup to a finder, the eyecup may become large due to the need to closely contact the face and the eyepiece without any gaps. In devices that the user observes with both eyes, such as binoculars and HMDs, a large eyecup narrows the field of view and makes it difficult for the user to grasp the surrounding situation, so use while moving is limited. Applying the angle-selective transmission element of the present invention to a finder is effective in solving such problems (eliminating the need for an eyecup or reducing its size).

[0070] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0071] 1 HMD (display device) 6,7 Angle-selective transmission element 6c opening

Claims

1. An angle-selective transmission element disposed in an optical path and having a plurality of apertures, a limiting means configured by the plurality of openings and limiting the passing direction of the light beam; The light beam passing portion of the limiting means is formed radially from a three-dimensionally predetermined point as a center, and the inside of the opening is filled with a material having a refractive index difference of 0.1 or less with respect to air. An angle-selective transmission element characterized by:

2. The light beam passing portion is formed radially from a point on the optical axis away from the angle-selective transmission element.

2. The angle-selective transmission element according to claim 1.

3. The surface is treated with anti-reflective coating 3. The angle-selective transmission element according to claim 1 or 2.

4. The first surface and the second surface having the plurality of openings in the angle-selective transmission element are configured in a regular tessellation shape.

4. The angle-selective transmission element according to claim 1, wherein the first and second light sources are arranged in a first direction and a second direction.

5. The first surface and the second surface having the plurality of openings in the angle-selective transmission element are configured as Archimedean tessellations using a plurality of types of regular polygons.

4. The angle-selective transmission element according to claim 1, wherein the first and second light sources are arranged in a first direction and a second direction.

6. The material is a porous, transparent material that contains more than 90% air.

6. The angle-selective transmission element according to claim 1,

7. The plurality of openings are separated by walls, and the walls are treated with an anti-reflection treatment.

7. The angle-selective transmission element according to claim 1, wherein the first and second light sources are arranged in a first direction and a second direction.

8. An angle-selective transmission element disposed in an optical path and formed by stacking a plurality of plates, a limiting means configured by a plurality of openings in the plurality of plates and limiting a passing direction of a light beam; The wall portion provided in the opening portion is composed of wall surfaces in at least two directions that are not parallel to the light passing direction, and the light beam passing portion in the limiting means is formed radially from a point that is three-dimensionally predetermined as a center. An angle-selective transmission element characterized by:

9. The central positions of the opening diameters of the openings are different between the front and rear of the laminated plates.

9. The angle-selective transmission element according to claim 8.

10. The opening size of the opening is different between the front and rear of the laminated plates.

9. The angle-selective transmission element according to claim 8.

11. The opening has a plurality of regions with different opening sizes or pipe lengths.

8. The angle-selective transmission element according to claim 1, wherein the first and second light sources are arranged in a first direction and a second direction.

12. The angle-selective transmission element according to any one of claims 1 to 11 is provided. A display device comprising:

13. a viewfinder having a display means and an eyepiece system; In the viewfinder, the angle-selective transmission element is disposed at an eye point corresponding to the position of the user's eyes.

13. The display device according to claim 12.

14. The limiting means is constituted by the plurality of openings radially extending from the eyepoint toward the eyepiece lens system.

14. The display device according to claim 13.

15. The limiting means is constituted by the plurality of openings formed in a plurality of plates along a direction from the eyepoint toward the eyepiece lens system.

14. The display device according to claim 13.

16. the eyepiece lens system is located between the display means and the angle-selective transmission element; The angle-selective transmission element is located between the eyepoint and the eyepiece lens system.

16. The display device according to claim 13, wherein the display device is a liquid crystal display.

17. A display device having a display means and an eyepiece lens system, the display device comprising a plurality of viewfinders corresponding to both eyes, and a plurality of angle-selective transmission elements disposed in the viewfinders at eye points corresponding to the positions of the eyes of a user, The angle-selective transmission element has a limiting means for limiting the passing direction of a light beam, The limiting means has a plurality of openings, the light beam passing portion is formed radially around the eye point, has a first opening in a first region toward the center of both eyes, and has a second opening in a second region away from the center of both eyes, and the opening of the first opening is narrower than the opening of the second opening. A display device comprising:

18. A display device having a display means and an eyepiece lens system, the display device comprising a plurality of viewfinders corresponding to both eyes, and a plurality of angle-selective transmission elements disposed in the viewfinders at eye points corresponding to the positions of the eyes of a user, The angle-selective transmission element has a limiting means for limiting the passing direction of a light beam, The limiting means has a plurality of openings, the light beam passing portion is formed radially around the eye point, has a first opening in a first region toward the center of both eyes, and has a second opening in a second region away from the center of both eyes, and the tube length of the first opening is longer than the tube length of the second opening. A display device comprising:

19. At least a part of the limiting means is formed along a curved surface of the eyepiece lens system.

20. The display device according to claim 18 .

20. A display device comprising a finder having a display means and an eyepiece lens system, and an angle-selective transmission element disposed in an optical path, The angle-selective transmission element is The light source includes a limiting means configured with a plurality of openings and limiting a passing direction of a light beam; the light beam passing portion of the limiting means is formed radially from a point that is three-dimensionally determined in advance as a center, the angle-selective transmission element disposed in the viewfinder at an eye point corresponding to the position of a user's eyes is composed of a plurality of plates or mask members having the openings, The opening of the opening on the side of the eyepoint in the plurality of plates or mask members is enlarged with respect to a line connecting the opening of the opening of the plate or mask member closest to the eyepiece lens system and the eyepoint. A display device comprising:

21. The amount of expansion of the opening of the second plate or mask member that is farther away from the eyepiece lens system than the first plate or mask member is larger than the amount of expansion of the opening of the first plate or mask member that is closer to the eyepiece lens system.

21. The display device according to claim 20.

22. The amount of enlargement of the aperture is proportional to the distance between the eyepiece lens system and the plate or the mask member.

22. The display device according to claim 21 .

23. The mask member has a plurality of regions between the plurality of openings that block light passing through the openings or light reflected by a lens surface of the eyepiece lens system.

21. The display device according to claim 20.

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