Retinal projection device

Abstract

It enables good Maxwell views even when not directly in front. [Solution] The retinal projection device 100A comprises a display 10 that displays an arbitrary image, a spherical multi-pinhole plate 20 having a spherical portion 22 in which a plurality of pinholes 21 are formed, and an optical system 30 that focuses the image displayed on the display 10 and passing through the plurality of pinholes 21 onto each point on the eyeball 200.

Description

Technical Field

[0001] The present invention relates to a retinal projection device, and more particularly to a device that directly projects an image onto the retina using Maxwell vision.

Background Art

[0002] There is Maxwell vision as a visual presentation method that does not require glasses. As one method of viewing a monochrome image with Maxwell vision, there is a method of converging an image passed through a pinhole to the center of the pupil by an optical system and projecting it onto the retina. According to such Maxwell vision, an image can be directly projected onto the retina regardless of the adjustment of the lens thickness, that is, the image can be viewed without glasses.

[0003] However, in Maxwell vision, since the image is converged to the center of the pupil, there is a problem that the viewing angle is narrow, such that when the eyeball rotates and the line of sight moves, the convergence point of the image deviates from the center of the pupil and the image cannot be seen. To address such a problem, a technique is known in which a plurality of pinholes are formed in a pinhole forming plate placed perpendicular to the optical axis, and the image is converged to a plurality of points on a virtual plane contacting the eyeball, so that even if the pupil moves up, down, left, or right due to the rotation of the eyeball, the pupil captures one of the convergence points and the image can be viewed (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The images passing through each pinhole in the pinhole-forming plate described above converge at points on a virtual plane in contact with the eyeball. In the case of forward viewing, the pupil lies on the virtual plane, so all of the light beam converged at the convergence point reaches the retina, allowing the entire image to be seen. However, in the case of up, down, left, and right viewing, the eyeball rotates and the pupil moves away from the virtual plane, creating a gap between the convergence point of the image on the virtual plane and the pupil. As a result, some of the light beam converged at the convergence point is blocked by the iris and cannot pass through the pupil, causing a portion of the image to be missing, i.e., the field of view to be narrowed. Therefore, the present invention aims to provide a retinal projection device that enables good Maxwellian vision even in views other than forward viewing. [Means for solving the problem]

[0006] According to one aspect of the present invention, a retinal projection device is provided that projects an image directly onto the retina, comprising: a display for displaying an arbitrary image; a spherical multi-pinhole plate having a spherical portion in which a plurality of pinholes are formed; and an optical system for focusing the image displayed on the display and passing through the plurality of pinholes onto each point on the eyeball. [Effects of the Invention]

[0007] According to the present invention, the image displayed on the screen and passing through the pinhole can be focused to each point on the spherical surface of the eyeball. No matter where the line of sight is directed, one of the convergence points on the eyeball will be located at the center of the pupil, allowing the user to view the image displayed on the screen without any loss of detail. This enables good Maxwellian vision even when not looking straight ahead. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram of a retinal projection device according to the first embodiment of the present invention. [Figure 2] This is a diagram illustrating the configuration of a spherical multi-pinhole plate as an example. [Figure 3] This is a schematic diagram of a retinal projection device according to a second embodiment of the present invention. [Figure 4]This is a schematic diagram of a retinal projection device according to a third embodiment of the present invention. [Figure 5] This is a diagram showing the configuration of a spherical multi-pinhole plate in a modified form. [Modes for carrying out the invention]

[0009] The embodiments of the present invention will be described in detail below, with reference to the drawings as appropriate. However, unnecessary details may be omitted. For example, detailed explanations of already well-known matters or redundant explanations of substantially identical configurations may be omitted. This is to avoid the following explanation becoming unnecessarily verbose and to facilitate understanding by those skilled in the art. The inventors provide the accompanying drawings and the following explanation so that those skilled in the art can fully understand the present invention, and do not intend to limit the subject matter described in the claims by these. In addition, the dimensions, thickness, and detailed shapes of each component depicted in the drawings may differ from those of the actual components.

[0010] (First Embodiment) Figure 1 is a schematic diagram of a retinal projection device according to a first embodiment of the present invention. The retinal projection device 100A according to this embodiment is an HMD (head-mounted display) type or glasses type VR (Virtual Reality) device equipped with a display 10, a spherical multi-pinhole plate 20, and an optical system 30. These components are arranged in a predetermined positional relationship within a housing (not shown). Figure 1 shows a sagittal or horizontal cross-section of these components, and also shows the user's eyeballs 200 when the device is worn.

[0011] The display 10 is a liquid crystal display or organic EL display of several inches in size and is positioned furthest from the eyeball 200. A driver (not shown in the figure) is connected to the display 10, and an arbitrary image is displayed on the display surface 11, which is normalized to the optical axis L of the optical system 30.

[0012] The optical system 30 is a relay lens optical system composed of multiple lenses and is positioned closest to the eyeball 200. As an example, Figure 1 shows an optical system 30 composed of a collimating lens 31 and a condensing lens 32. The collimating lens 31 is positioned at a distance of the focal length from the pinhole 21 of the spherical multi-pinhole plate 20. The condensing lens 32 is positioned at a distance of the focal length from the eyeball 200. As described above, the optical axis L of the optical system 30 coincides with the normal direction of the display surface 11 of the display 10.

[0013] The spherical multi-pinhole plate 20 is a thin plate member having a spherical portion 22 with multiple pinholes 21 formed thereon and a planar edge portion 23, and is positioned between the display 10 and the optical system 30. More specifically, the spherical portion 22 protrudes toward the display surface 11 of the display 10, and is positioned such that the center of the spherical portion 22 and the center of the radius of curvature are located on the optical axis L of the optical system 30.

[0014] Figure 2 is a diagram showing the configuration of a spherical multi-pinhole plate according to one example. In this example, the spherical multi-pinhole plate 20 has a shape in which the central part of a disc-shaped thin plate member is bulging in a roughly hemispherical shape. This bulging part is the spherical portion 22. The planar edge portion 23 is a member that is in contact with the periphery of the spherical portion 22 and supports the spherical portion 22.

[0015] The radius of curvature of the spherical portion 22 is approximately the same as that of a human eyeball (eyeball 200). Although the eyeball is not a perfect sphere and has slightly different shapes in the anterior-posterior direction from the cornea to the retina and in the lateral direction, if considered as a sphere, its radius of curvature is said to be approximately 12 mm on average. Therefore, the radius of curvature of the spherical portion 22 is set to 12 mm.

[0016] On the spherical surface portion 22, a pinhole 21 is formed at the center of the spherical surface, and further, eight pinholes 21 are formed at positions 25° from the center of the radius of curvature so as to surround the pinhole 21. The diameter of each pinhole 21 is 1 mm. The angle of 25° is an example of a numerical value determined by the optical characteristics of the collimating lens 31. That is, the pinhole 21 is formed at the focal position of the light beam by the collimating lens 31.

[0017] Note that the arrangement position, size, and number of the above-mentioned pinholes 21 are merely examples, and these may be determined in consideration of the movable range of the pupil. The pupil has different movable ranges in the horizontal direction (left - right direction) and the vertical direction (up - down direction). Taking the front view as 0°, it can move ±40 - 50° in the left - right direction and ±20 - 30° in the up - down direction. Therefore, appropriate numbers of pinholes 21 may be formed at appropriate positions within such a movable range of the pupil. Also, if the diameter of the pinhole 21 is too large, the incident light will increase and the resolution will decrease. On the contrary, if it is too small, the image will become dark or the influence of diffraction will occur. Therefore, it is preferably in the range of 0.1 - 2 mm.

[0018] Returning to FIG. 1, the convergence points of the images passing through each pinhole 21 will be described. Here, the pinhole 21 at the center of the spherical surface of the spherical surface portion 22 is the pinhole H2, the pinhole 21 at a position shifted upward in the figure from H2 is the pinhole H1, and the pinhole 21 at a position shifted downward in the figure from H2 is the pinhole H3. The image displayed on the display surface 11 of the display 10 and passing through H1 is represented by a dashed - dotted line, the image passing through H2 is represented by a broken line, and the image passing through H3 is represented by a double - dashed - dotted line.

[0019] The image displayed on the display surface 11 of the display 10 and passing through the pinhole H2 spreads radially with H2 as a point source. The light beam spreading radially from H2 is collimated in parallel by the collimating lens 31 and enters the condensing lens 32, and is condensed by the condensing lens 32 at the convergence point C2 on the optical axis L and on the eyeball 200. In the case of front view, all the light beams condensed at C2 pass through the pupil 201, and the user can visually recognize the image displayed on the display 10 without omission.

[0020] The image displayed on the display surface 11 of the display 10 and passing through the pinhole H1 spreads radially with H1 as a point light source. The light beam spreading radially from H1 is collimated in parallel by the collimating lens 31 and enters the condenser lens 32, and is converged by the condenser lens 32 to a convergence point C1 on the eyeball 200, which is below C2 in the drawing. When the eyeball 200 rotates counterclockwise in the drawing, the pupil 201 moves downward in the drawing accordingly. However, since C1 is located on the eyeball 200, all the light beams converged at C1 pass through the pupil 201, and the user can visually recognize the image displayed on the display 10 without omission.

[0021] Similarly, the image displayed on the display surface 11 of the display 10 and passing through the pinhole H3 converges to a convergence point C3 on the eyeball 200, which is above C2 in the drawing. When the eyeball 200 rotates clockwise in the drawing, the pupil 201 moves upward in the drawing accordingly. However, since C3 is located on the eyeball 200, all the light beams converged at C3 pass through the pupil 201, and the user can visually recognize the image displayed on the display 10 without omission.

[0022] (Second Embodiment) FIG. 3 is a schematic diagram of a retinal projection device according to a second embodiment of the present invention. Hereinafter, the retinal projection device 100B according to the present embodiment will be mainly described with respect to the differences from the retinal projection device 100A according to the first embodiment, and the description of the same points may be omitted to avoid duplication of description.

[0023] The retinal projection device 100B is an HMD type or glasses type VR device including a display 10, a spherical multi-pinhole plate 20, and an optical system 30. These components are arranged in a predetermined positional relationship within a housing not shown in the figure. Note that FIG. 3 shows a sagittal section or a horizontal section of these components, and also shows the user's eyeball 200 when the device is worn.

[0024] The display 10 and the spherical multi-pinhole plate 20 are the same as in the first embodiment, but the orientation of the spherical portion 22 of the spherical multi-pinhole plate 20 is different. The spherical multi-pinhole plate 20 is arranged so that the spherical portion 22 protrudes toward the optical system 30.

[0025] The optical system 30 includes a transmissive mirror device (TMD) 33. The TMD 33 is a device that utilizes mirrors and has the property of reflecting a light beam incident on one surface and emitting it from the other surface, thereby converging the image to a position symmetrical to the plane. Specifically, examples include CMA (crossed mirror array), AI (aerial imaging) plate, and DCRA (dihedral corner reflector array).

[0026] The TMD33 can be positioned at any angle relative to the spherical multi-pinhole plate 20. For example, as shown in the figure, if the display 10 and the spherical multi-pinhole plate 20 are positioned such that the normal direction of the display surface 11 of the display 10 (up and down direction in the figure) is perpendicular to the line of sight direction (left direction in the figure) when viewed from the front, the TMD33 is positioned at a 45° angle relative to the spherical multi-pinhole plate 20, exactly halfway between the spherical portion 22 of the spherical multi-pinhole plate 20 and the eyeball 200, so that the image converges towards the eyeball 200.

[0027] The convergence points of the images passing through each pinhole 21 will now be explained. Here, the pinhole 21 at the center of the spherical surface of the spherical part 22 is denoted as pinhole H2, the pinhole 21 located to the left of H2 in the figure is denoted as pinhole H1, and the pinhole 21 located to the right in the figure is denoted as pinhole H3. The image displayed on the display surface 11 of the display 10 that passes through H1 is represented by a dashed line, the image that passes through H2 is represented by a dashed line, and the image that passes through H3 is represented by a double-dashed line.

[0028] The image displayed on the display surface 11 of the display 10 and passing through the pinhole H2 spreads out radially with H2 as the point light source. The light beam spreading radially from H2 enters the TMD 33 and is converged by the TMD 33 to a convergence point C2 on the eyeball 200, which is in a plane-symmetric position. In a frontal view, all of the light beam converged at C2 passes through the pupil 201, and the user can see the image displayed on the display 10 without any loss of detail.

[0029] The image displayed on the display surface of the display 10 and passing through the pinhole H1 spreads out radially with H1 as the point light source. The light beam spreading radially from H1 is incident on the TMD 33 and converges on the eyeball 200 at a point C1, which is symmetrical to C2 in the diagram and is located below C2. As the eyeball 200 rotates counterclockwise in the diagram, the pupil 201 also moves downward in the diagram. However, since C1 is located on the eyeball 200, all of the light beam that converges to C1 passes through the pupil 201, and the user can view the image displayed on the display 10 without any loss of detail.

[0030] Similarly, the image displayed on the display surface 11 of the display 10 and passing through the pinhole H3 converges to a convergence point C3 on the eyeball 200, which is located above C2 in the diagram. As the eyeball 200 rotates clockwise in the diagram, the pupil 201 also moves upward in the diagram. However, since C3 is located on the eyeball 200, all the light beam that converges to C3 passes through the pupil 201, and the user can view the image displayed on the display 10 without any loss of detail.

[0031] (Third embodiment) Figure 4 is a schematic diagram of a retinal projection device according to a third embodiment of the present invention. Hereinafter, the differences between the retinal projection device 100C according to this embodiment and the retinal projection device 100A according to the first embodiment will be mainly described, and similar points may be omitted from the explanation to avoid repetition.

[0032] The retinal projection device 100C is an HMD-type or glasses-type VR device equipped with a display 10, a spherical multi-pinhole plate 20, and an optical system 30. These components are arranged in a predetermined positional relationship within a housing (not shown). Figure 4 shows a sagittal or horizontal cross-section of these components, along with the user's eyeball 200 when the device is worn. In addition, for the purpose of illustrating the light beam, two retinal projection devices 100C are shown vertically in Figure 4.

[0033] The spherical multi-pinhole plate 20 is positioned so that its spherical portion 22 protrudes toward the optical system 30. The optical system 30 includes a half-mirror 34. The half-mirror 34 is positioned parallel to the spherical multi-pinhole plate 20 at a location exactly midway between the spherical portion 22 of the spherical multi-pinhole plate 20 and the eyeball 200.

[0034] The surfaces of the spherical multi-pinhole plate 20, specifically the spherical portion 22 and the planar edge portion 23, that face the half-mirror 34 are designed to retroreflect the light reflected from the half-mirror 34. For example, the surfaces of the half-mirror 34 can be made retroreflective by coating them with glass beads or by attaching a prism-type reflective sheet with a fine prism structure on its surface.

[0035] The convergence points of the images passing through each pinhole 21 will now be explained. Here, the pinhole 21 at the center of the spherical surface of the spherical part 22 is denoted as pinhole H2, the pinhole 21 located above H2 in the figure is denoted as pinhole H1, and the pinhole 21 located below H2 in the figure is denoted as pinhole H3. The light beam displayed on the display surface 11 of the display 10, passing through H1, is represented by a dashed line, the light beam passing through H2 is represented by a dashed line, and the light beam passing through H3 is represented by a double-dashed line.

[0036] The image displayed on the display surface 11 of the display 10 and passing through the pinhole H2 spreads radially from H2 as a point light source. A portion of the light beam spreading radially from H2 is specularly reflected by the half mirror 34 and heads toward the spherical multi-pinhole plate 20. The reflected light from the half mirror 34 is retroreflective from the surface of the spherical multi-pinhole plate 20 and heads toward the half mirror 34, and a portion of it passes through the half mirror 34 and converges at the convergence point C2 on the eyeball 200. When viewed from the front, all of the light beam that converges at C2 passes through the pupil 201, and the user can see the image displayed on the display 10 without any loss of detail.

[0037] The image displayed on the display surface 11 of the display 10 and passing through the pinhole H1 spreads out radially with H1 as the point light source. A portion of the light beam spreading radially from H1 is specularly reflected by the half mirror 34 and heads toward the spherical multi-pinhole plate 20. The reflected light from the half mirror 34 is retroreflective from the surface of the spherical multi-pinhole plate 20 and heads toward the half mirror 34, and a portion of it passes through the half mirror 34 and converges at a convergence point C1 on the eyeball 200, which is above C2 in the figure. As the eyeball 200 rotates clockwise in the figure, the pupil 201 also moves upward in the figure, but since C1 is located above the eyeball 200, all of the light beam that converges at C1 passes through the pupil 201, and the user can see the image displayed on the display 10 without any loss of image.

[0038] Similarly, the image displayed on the display surface 11 of the display 10 and passing through the pinhole H3 converges to a convergence point C3 on the eyeball 200, which is located below C2 in the diagram. As the eyeball 200 rotates counterclockwise in the diagram, the pupil 201 also moves downward in the diagram. However, since C3 is located above the eyeball 200, all the light beam that converges to C3 passes through the pupil 201, and the user can view the image displayed on the display 10 without any loss of detail.

[0039] ≪Effects≫ As described above, the retinal projection devices 100A, 100B, and 100C can focus the image displayed on the display 10 and passed through the pinhole 21 to various points on the eyeball. Therefore, no matter where the line of sight is directed, one of the convergence points on the eyeball 200 will be located at the center of the pupil, allowing the user to view the image displayed on the display 10 without any loss of detail. This enables good Maxwellian vision even when not looking straight ahead.

[0040] ≪Variations≫ In the retinal projection devices according to each of the above embodiments, by providing a prism, a half-mirror, or the like between the optical system 30 and the eyeball 200, a device can be configured that realizes AR (Augmented Reality) by superimposing an image displayed on the display 10 onto the real image.

[0041] The radius of curvature of the spherical portion 22 of the spherical multi-pinhole plate 20 does not need to be 12 mm, which is the average radius of curvature of the human eyeball; it may be larger or smaller. If the radius of curvature of the spherical portion 22 is large or small, an appropriate optical element can be added to the optical system 30 so that the image passing through each pinhole 21 converges to the desired position on the eyeball 200.

[0042] The spherical portion 22 does not need to be approximately hemispherical; it may be a smaller, coronal shape, taking into account the range of motion of the pupil.

[0043] In the retinal projection devices according to the first and second embodiments, the planar edge portion 23 of the spherical multi-pinhole plate 20 can be omitted.

[0044] A rotational drive unit may be added to each of the above embodiments of the retinal projection device to continuously rotate the spherical multi-pinhole plate 20. Figure 5 is a diagram of the configuration of a spherical multi-pinhole plate according to a modified example. The rotational drive unit 40 is composed of a small electric motor or the like, and continuously rotates the spherical multi-pinhole plate 20 at an appropriate speed with the rotation axis being the line connecting the center of the spherical surface of the spherical part 22 and the center of the radius of curvature, which in the example of the first embodiment shown in Figure 1 is the optical axis L. The direction of rotation can be either left or right.

[0045] In a rotationally driven spherical multi-pinhole plate 20, it is sufficient to have one pinhole 21 on a circle centered on the axis of rotation in the spherical portion 22. In the example shown in Figure 5, two pinholes 21 are formed on the same circle, separated by 180°, but there may be only one pinhole 21 on the same circle.

[0046] As the spherical multi-pinhole plate 20 rotates, the point of image convergence on the eyeball 200 also rotates in a circle. Therefore, if the pupil 201 is on this circle in any view other than a direct frontal view, the user can view the image displayed on the display 10 without any loss of image due to the afterimage effect. By continuously rotating the spherical multi-pinhole plate 20 in this way, the number of pinholes 21 can be reduced, making it easier to arrange multiple pinholes 21 in a narrow area of ​​the spherical portion 22.

[0047] In a rotating spherical multi-pinhole plate 20, the pinholes 21 farther from the axis of rotation move faster than the pinholes 21 closer to the axis of rotation, resulting in the same effect as a high-speed shutter and reduced light intensity. Therefore, to equalize the light intensity between the pinholes 21 farther from the axis of rotation and those closer to the axis of rotation, the diameter of the pinholes 21 farther from the axis of rotation may be increased, their number may be increased, or a combination of these may be used. Alternatively, an ND filter may be provided for the pinholes 21, with the filter density increasing for pinholes 21 closer to the axis of rotation.

[0048] As described above, embodiments have been explained as examples of the technology in the present invention. For this purpose, accompanying drawings and a detailed description have been provided. Therefore, among the components described in the accompanying drawings and detailed description, there may be not only components that are essential for solving the problem, but also components that are not essential for solving the problem, in order to illustrate the above technology. For this reason, the mere fact that these non-essential components are described in the accompanying drawings and detailed description should not be immediately assumed to be essential. Furthermore, since the above embodiments are for the purpose of illustrating the technology in the present invention, various changes, substitutions, additions, omissions, etc., can be made within the scope of the claims or equivalents. [Explanation of Symbols]

[0049] 100A, 100B, 100C Retinal Projection Devices 10 displays 11 Display surface 20 Spherical Multi-Pinhole Plate 21 Pinholes 22 Spherical part 23 Flat edge 30 Optical system 31. Collimating lens (relay lens optical system) 32. Focusing lens (relay lens optical system) 33 Transparent Mirror Devices 34 Half Mirror 40 Rotary drive unit 200 Eyeball

Claims

1. A device that projects an image directly onto the retina, A display that shows any image, A spherical multi-pinhole plate having a spherical portion in which multiple pinholes are formed, The optical system comprises an optical system that focuses the image displayed on the display and passing through the plurality of pinholes onto each point on the eyeball. A retinal projection device characterized by the following features.

2. The optical system has a relay lens optical system, The spherical multi-pinhole plate is arranged such that the spherical portion protrudes toward the display surface side of the display. The retinal projection device according to claim 1.

3. The optical system has a transmissive mirror device that focuses the incident light beam to a plane-symmetric position, The spherical multi-pinhole plate is arranged such that the spherical portion protrudes toward the optical system. The retinal projection device according to claim 1.

4. The spherical multi-pinhole plate has a planar edge that is in contact with the periphery of the spherical portion, and the spherical portion is arranged in a direction that protrudes toward the optical system side. The optical system has a half mirror, The half-mirror is arranged parallel to the spherical multi-pinhole plate, The spherical portion and the planar edge portion of the spherical multi-pinhole plate are configured to retroreflect the light reflected from the half-mirror on the opposing surfaces of the half-mirror. The retinal projection device according to claim 1.

5. The radius of curvature of the spherical portion is approximately the same as that of the human eyeball. A retinal projection device according to any one of claims 1 to 4.

6. The spherical multi-pinhole plate is equipped with a rotational drive unit that continuously rotates the spherical multi-pinhole plate using the line connecting the center of the spherical portion on the surface and the center of the radius of curvature as the axis of rotation. A retinal projection device according to any one of claims 1 to 4.

7. A pinhole is formed on the spherical portion on a circle centered on the axis of rotation. The retinal projection device according to claim 6.

8. In the spherical portion, a filter is provided in which the diameter and / or number of pinholes closer to the axis of rotation differ from those further away from the axis of rotation, or in which the pinholes closer to the axis of rotation produce a greater amount of light reduction. The retinal projection device according to claim 6.

9. The spherical multi-pinhole plate is equipped with a rotational drive unit that continuously rotates the spherical multi-pinhole plate using the line connecting the center of the spherical portion on the surface and the center of the radius of curvature as the axis of rotation. The retinal projection device according to claim 5.

10. A pinhole is formed on the spherical portion on a circle centered on the axis of rotation. The retinal projection device according to claim 9.

11. In the spherical portion, a filter is provided in which the diameter and / or number of pinholes closer to the axis of rotation differ from those further away from the axis of rotation, or in which the pinholes closer to the axis of rotation produce a greater amount of light reduction. The retinal projection device according to claim 9.

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