Head-mounted displays and light field displays

Abstract

A light field display of the flat panel type comprising a flat panel display, a lens array, and an aperture array arranged in one direction, wherein the flat panel display has a plurality of pixels arranged in two dimensions, the lens array has a plurality of lenses arranged in two dimensions, each of which images light rays emitted from a group of pixels consisting of a plurality of pixels arranged adjacent to each other in the flat panel display, and the aperture array is arranged adjacent to the lens array and has a plurality of apertures arranged in two dimensions so as to correspond one-to-one with the plurality of lenses, and each of the plurality of apertures includes at least one aperture of any shape that is a circle, an ellipse, or a polygon, having an area smaller than the area of ​​the corresponding lens among the plurality of lenses in a planar view.

Description

[Technical Field]

[0001] This invention relates to a head-mounted display and a light field display. [Background technology]

[0002] Patent Document 1 states, "In order to make the width of the magnified image of one pixel 1a smaller than the lens pitch p, and to make the magnified images of multiple pixels 1a visible through one lens 2a, and to eliminate crosstalk between light rays and enable blur-free stereoscopic display, an aperture array 3 is introduced and the width of the aperture 3a is made to match the width of the magnified image of pixel 1a, so that one pixel 1a is visible through one lens 2a" (0038). [Prior art document] [Patent] [Patent Document 1] Japanese Patent Publication No. 2021-165790 [Overview of the project]

[0003] In a first embodiment of the present invention, a flat-panel light field display is provided, comprising a flat panel display, a lens array, and an aperture array arranged in one direction. In the light field display, the flat panel display has a plurality of pixels arranged in two dimensions, the lens array has a plurality of lenses arranged in two dimensions, each of which images a light ray emitted from a group of pixels consisting of a plurality of pixels arranged adjacent to each other in the flat panel display, and the aperture array is arranged adjacent to the lens array and has a plurality of apertures arranged in two dimensions to correspond one-to-one with the plurality of lenses, each of which apertures includes at least one aperture of any shape that is a circle, an ellipse, or a polygon, having an area smaller than the area of ​​the corresponding lens among the plurality of lenses in a plan view.

[0004] In the light field display described above, the aperture array may be a transmissive display in which the shape of at least one of the apertures can be electronically controlled.

[0005] In any of the above light field displays, the transmissive display may change the shape of at least one of the openings in each of the openings over time.

[0006] In any of the above light field displays, the transmissive display may alternately display, at each of the apertures, a circular annular aperture whose center coincides with the optical axis of the corresponding lens and whose center is shielded from light, and a circular small-diameter aperture whose center coincides with the optical axis of the corresponding lens and whose area in a plan view is less than or equal to half the area of ​​the corresponding lens.

[0007] In any of the above light field displays, the transmissive display may vary the shape of at least one of the apertures in each of the apertures according to their position in the two-dimensional plane in which the plurality of apertures are arranged.

[0008] In any of the above light field displays, the transmissive display may display, depending on the position of each opening in the plane, a circular annular opening whose center coincides with the optical axis of the corresponding lens and whose center is shielded from light, or a circular small-diameter opening whose center coincides with the optical axis of the corresponding lens and whose area in a plan view is less than or equal to half the area of ​​the corresponding lens.

[0009] In any of the above light field displays, the plurality of pixels of the flat panel display are arranged in one direction closer to the lens array than the focal plane of the lens array, thereby a virtual three-dimensional image may be displayed in the air.

[0010] A second embodiment of the present invention provides a head-mounted display comprising any of the above-described light field displays.

[0011] A third aspect of the present invention provides a head-mounted display. The head-mounted display comprises any of the above-described light field displays and a lens that further forms a virtual image of the virtual image thereof.

[0012] In any of the above light field displays, in a plan view, the area of ​​at least one of the apertures may be 80% or less of the area of ​​the corresponding lens.

[0013] In any of the above light field displays, each of the apertures may include a circular annular aperture whose center coincides with the optical axis of the corresponding lens and whose center is shielded from light.

[0014] In any of the above light field displays, each aperture may include four small circular apertures that are equally spaced apart from each other around the optical axis of the corresponding lens in a plan view, and each has a radius of no more than 1 / (1+√2) times the radius of the corresponding lens.

[0015] In any of the above light field displays, each of the apertures may include a single circular small-diameter aperture whose center coincides with the optical axis of the corresponding lens and which has an area of ​​no more than half the area of ​​the corresponding lens in a plan view.

[0016] In any of the above-described light field displays, the flat panel display, the aperture array, and the lens array may be arranged in this order in the aforementioned one direction.

[0017] In any of the above light field displays, the flat panel display, the lens array, and the aperture array may be arranged in this order in the one direction.

[0018] In any of the above light field displays, the plurality of lenses of the lens array and the plurality of apertures of the aperture array may be two-dimensionally orthogonally arranged.

[0019] In any of the above light field displays, the plurality of lenses of the lens array and the plurality of apertures of the aperture array may be two-dimensionally arranged in a honeycomb shape.

[0020] Note that the above summary of the invention does not enumerate all the features of the present invention. Also, sub-combinations of these feature groups can also be inventions.

Brief Description of the Drawings

[0021] [Figure 1] It is a schematic side view showing an outline of a head-mounted display 10 according to the first embodiment. [Figure 2] It is a diagram for explaining the imaging of light rays in an infinite conjugate imaging type light field display. [Figure 3] It is a diagram for explaining the imaging of light rays in a real image imaging type light field display. [Figure 4] It is a diagram for explaining the imaging of light rays in a virtual image imaging type light field display. [Figure 5] It is a diagram for explaining the spread of light rays in infinite conjugate imaging. [Figure 6] It is a diagram for explaining the spread of light rays in real image imaging. [Figure 7] It is a diagram showing an example of an imaging system. [Figure 8] It is a diagram showing an example of the pupil function of a circular aperture in the XY plane. [Figure 9]This shows the amplitude distribution in the X-axis direction of the Fourier transform image of the pupil function of a circular aperture. [Figure 10] This shows the intensity distribution in the X-axis direction of the Fourier transform image of the pupil function of a circular aperture. [Figure 11] This shows the intensity distribution in the XY plane of the Fourier transform image of the pupil function of a circular aperture. [Figure 12] This figure shows an example of the pupil function of an annular aperture in the XY plane. [Figure 13] This shows the amplitude distribution in the X-axis direction of the Fourier transform image of the pupil function of the annular aperture. [Figure 14] This shows the intensity distribution in the X-axis direction of the Fourier transform image of the pupil function of the annular aperture. [Figure 15] This shows the intensity distribution of the pupil function of the annular aperture in the XY plane of the Fourier transform image. [Figure 16] The point image response functions in the XY plane at 0.1 mm intervals within a distance range of 19.6 to 20.4 mm from the lens in the Z-axis direction are shown for each case where (a) a circular aperture and (b) an annular aperture are used as the pupil function. [Figure 17] The following shows the change in intensity of the point image response function in the Y-axis direction with respect to distance in the Z-axis direction when a circular aperture is used as the pupil function. [Figure 18] The intensity change of the point image response function in the Y-axis direction with respect to distance in the Z-axis direction is shown for the case where the annular aperture is used as the pupil function. [Figure 19] (a) When a circular aperture and (b) annular aperture are used as pupil functions, the images in the XY plane at 0.1 mm intervals within a distance range of 19.6 to 20.4 mm from the lens in the Z-axis direction are shown. [Figure 20] This figure illustrates a virtual image-forming type light field display 100 according to the first embodiment of this model, in which at least one aperture 135 included in each aperture 131 of the transmissive display 130 is a single annular aperture. [Figure 21]This figure illustrates a virtual image-forming type light field display 100 according to a second embodiment of this present invention, in which at least one aperture 135 included in each aperture 131 of the transmissive display 130 is four small-diameter circular apertures arranged vertically and horizontally. [Figure 22] This figure illustrates a virtual image-forming type light field display 100 according to a third embodiment of this model, in which at least one aperture 135 included in each aperture 131 of the transmissive display 130 is a single small-diameter circular aperture smaller in diameter than the lens 121 of the lens array 120. [Figure 23] This is a diagram illustrating a virtual image-forming type light field display using a comparative example. [Figure 24] The intensity change of the point image response function in the Y-axis direction with respect to distance in the Z-axis direction in the comparative example is shown. [Figure 25] This shows the change in intensity of the point image response function in the Y-axis direction with respect to distance in the Z-axis direction in the first embodiment of this model. [Figure 26] This shows the change in intensity of the point image response function in the Y-axis direction with respect to distance in the Z-axis direction in the second embodiment of this model. [Figure 27] This shows the change in intensity of the point image response function in the Y-axis direction with respect to distance in the Z-axis direction in the third embodiment of this model. [Figure 28] The images in the XY plane at 40 mm intervals within a distance range of -520 to -320 mm from the lens in the Z-axis direction are shown for each of the following cases: (a) circular aperture of the comparative example, (b) annular aperture of the first embodiment, (c) deformed aperture of the second embodiment, and (d) small-diameter circular aperture of the third embodiment, each used as the pupil function. [Figure 29] For the comparative example light field display, enlarged images of the image at a Z coordinate position of -440 mm and the image at a Z coordinate position of -480 mm are shown. [Figure 30] In the first embodiment of this light field display 100, the image at a Z coordinate position of -440 mm and the image at a Z coordinate position of -480 mm are shown enlarged. [Figure 31]In the light field display 100 of the second embodiment of this present invention, the image at a Z coordinate position of -440 mm and the image at a Z coordinate position of -480 mm are shown enlarged. [Figure 32] In the third embodiment of this light field display 100, the images at a Z coordinate position of -440 mm and the images at a Z coordinate position of -480 mm are shown enlarged. [Figure 33] For the comparative example light field display, enlarged images of the image at a Z coordinate position of -360 mm and the image at a Z coordinate position of -320 mm are shown. [Figure 34] In the first embodiment of this light field display 100, the image at a Z coordinate position of -360 mm and the image at a Z coordinate position of -320 mm are shown enlarged. [Figure 35] In the light field display 100 of the second embodiment of this model, the image at a Z coordinate position of -360 mm and the image at a Z coordinate position of -320 mm are shown enlarged. [Figure 36] In the third embodiment of this light field display 100, the image at a Z coordinate position of -360 mm and the image at a Z coordinate position of -320 mm are shown enlarged. [Figure 37] (a) An image of the Z coordinate position at -480 mm using a circular aperture of the comparative example, and (b) an image of the Z coordinate position at -480 mm using an annular aperture of the first embodiment are shown side by side and enlarged. [Figure 38] (a) An image of the Z coordinate position at -480 mm using a circular aperture of the comparative example, and (c) an image of the Z coordinate position at -480 mm using a deformed aperture of the second embodiment are shown side by side and enlarged. [Figure 39] (a) An image of the comparative example at a Z coordinate position of -480 mm using a circular aperture, and (c) an image of the third embodiment at a Z coordinate position of -480 mm using a small-diameter circular aperture are shown side by side and enlarged. [Figure 40] (a) An image of the Z coordinate position at -320 mm using a circular aperture of the comparative example, and (b) an image of the Z coordinate position at -320 mm using an annular aperture of the first embodiment are shown side by side and enlarged. [Figure 41](a) An image of the Z coordinate position at -320 mm using a circular aperture of the comparative example, and (c) an image of the Z coordinate position at -320 mm using a deformed aperture of the second embodiment are shown side by side and enlarged. [Figure 42] (a) An image of the comparative example at a Z coordinate position of -320 mm using a circular aperture, and (c) an image of the third embodiment at a Z coordinate position of -320 mm using a small-diameter circular aperture are shown side by side and enlarged. [Figure 43] The intensity distribution in the X-axis direction of the point image response function at the observation position described above is shown for the comparative example light field display. [Figure 44] The intensity distribution in the X-axis direction at the observation position described above is shown for the light field display 100 of the first embodiment of this present invention. [Figure 45] The intensity distribution in the X-axis direction at the observation position described above is shown for the light field display 100 of the second embodiment of this present invention. [Figure 46] The intensity distribution in the X-axis direction at the observation position described above is shown for the light field display 100 of the third embodiment of this present invention. [Figure 47] This is a schematic side view showing an outline of the head-mounted display 11 according to the second embodiment. [Figure 48] This is a schematic side view showing an outline of the head-mounted display 12 according to the third embodiment. [Figure 49] This is a schematic plan view showing a lens array 220 and a transmissive display 230, which are modified versions of the lens array 120 and transmissive display 130 in the first embodiment. [Figure 50] This is a schematic side view showing an outline of the head-mounted display 13 according to the fourth embodiment. [Modes for carrying out the invention]

[0022] The present invention will be described below through embodiments, but these embodiments are not intended to limit the scope of the claims. Furthermore, not all combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0023] Figure 1 is a schematic side view showing the outline of a head-mounted display 10 according to the first embodiment. Figure 1 shows mutually orthogonal XYZ axes. In Figure 1, the Z-axis direction is left-right with respect to the plane of the paper, with the right direction being the positive Z-axis direction. The X-axis direction is front-back with respect to the plane of the paper, with the front direction being the positive X-axis direction. The Y-axis direction is up-down with respect to the plane of the paper, with the up direction being the positive Y-axis direction. In subsequent figures, the three axes corresponding to the XYZ axes are shown, and redundant explanations are omitted.

[0024] The head-mounted display 10 includes a flat-panel type light field display 100. In Figure 1, the light field display 100 is shown with a dashed frame. The head-mounted display 10 of this embodiment further includes a housing 20 that houses the light field display 100. The housing 20 may have a structure that can be attached to the user's head, but such a structure is not shown in Figure 1 and subsequent figures, and is schematically shown with just a rectangular frame. The head-mounted display 10 may further include a power supply and the like to supply power to the light field display 100, but in this application, for the sole purpose of clarifying the explanation, the illustration and explanation of the power supply and other electrical systems are omitted.

[0025] The head-mounted display 10 of this embodiment utilizes a virtual image-forming type light field display by a light field display 100 to reduce blurring that occurs in the stereoscopic image.

[0026] The light field display 100 comprises a flat panel display 110, a lens array 120, and a transmissive display 130 arranged in one direction. In the light field display 100 of this embodiment, the flat panel display 110, the lens array 120, and the transmissive display 130 are arranged in this order in the Z-axis direction, as shown in Figure 1. The light field display 100 may further include a controller for controlling the driving of the flat panel display 110 and the transmissive display 130, but in this application, for the sole purpose of clarifying the explanation, the illustration and description of the electrical system such as the controller are omitted.

[0027] The flat panel display 110 has a plurality of pixels 111 arranged in two dimensions. In this embodiment, the plurality of pixels 111 are arranged in two dimensions in the XY plane. In Figure 1, for the purpose of clarifying the explanation, only the arrangement of some pixels 111 in the Y-axis direction is schematically shown, and the arrangement in the X-axis direction is omitted. In the following figures, for the purpose of clarifying the explanation, the illustration of pixels 111 is omitted.

[0028] The lens array 120 has a plurality of lenses 121 arranged in two dimensions. In this embodiment, the plurality of lenses 121 are arranged orthogonally in two dimensions in the XY plane. In Figure 1, for the purpose of clarifying the explanation, only the arrangement of some lenses 121 in the Y-axis direction is schematically shown, and the arrangement in the X-axis direction is omitted. Each of the plurality of lenses 121 images light rays emitted from a group of pixels consisting of a plurality of pixels 111 arranged adjacent to each other in the flat panel display 110, as indicated by the linear arrows in Figure 1. Details of how the lenses 121 image these light rays will be described later with reference to Figures 2 to 4.

[0029] The transmissive display 130 is positioned adjacent to the lens array 120. The transmissive display 130 has a plurality of apertures 131 arranged in two dimensions so as to correspond one-to-one with the plurality of lenses 121 of the lens array 120. More specifically, the transmissive display 130 forms a plurality of apertures 131 on the screen, arranged in two dimensions so as to correspond one-to-one with the plurality of lenses 121 of the lens array 120.

[0030] In this embodiment, the multiple openings 131 are arranged orthogonally in two dimensions within the XY plane. More specifically, the transparent display 130 comprises multiple orthogonally arranged openings 131 on the screen within the XY plane. Each opening 131 includes at least one opening 135. Each opening 131 may include, for example, one opening 135 or four openings 135.

[0031] The transmissive display 130 can electronically control the shape of at least one aperture 135 in each aperture 131. More specifically, the transmissive display 130 can electronically control the shape of at least one aperture 135 included in each aperture 131 that makes up the screen. That is, the transmissive display 130 can electronically control the shape of the pupil function of each lens 121 that makes up the lens array 120. As an example, the transmissive display 130 may electronically form a light-shielding portion in each aperture 131 that makes up the screen, which blocks a portion of the light rays emitted from the corresponding plurality of pixels 111 of the flat panel display 110 via the corresponding lens 121, and define the contour of an aperture 135 that transmits the rest of the light rays with the light-shielding portion. In this way, the transmissive display 130 displays the aperture shape used as the pupil function, and various two-dimensional shapes that can be displayed by the transmissive display 130 can be used as the aperture shape. Furthermore, the transmissive display 130 may change the shape of the aperture over time or change the shape of the aperture according to the position of the lens 121.

[0032] In Figure 1, for the sole purpose of clarifying the explanation, the light-shielding areas defining the apertures 135 of each aperture 131 displayed on the transmissive display 130 are schematically shown as black-filled regions, and only one aperture 135 contained within one aperture 131 is indicated by an arrow. Details such as the configuration in which multiple apertures 131 are arranged orthogonally in two dimensions and the shape of the apertures 135 will be described later. Note that the transmissive display 130 is an example of an aperture array.

[0033] In the light field display 100 of this embodiment, the multiple pixels 111 of the flat panel display 110 are positioned closer to the lens array 120 than the focal plane of the lens array 120, in the direction in which the flat panel display 110, lens array 120, and transmissive display 130 are aligned, i.e., in the Z-axis direction. As a result, the light field display 100 of this embodiment displays a three-dimensional image as a virtual image in the air.

[0034] More specifically, the light field display 100 uses a lens array 120 to project light rays from the pixels 111 of the flat panel display 110 into a virtual image in the space opposite to the eyes of the observer of the stereoscopic image, i.e., the wearer of the head-mounted display 10. In this embodiment, the light field display 100 combines a transmissive display 130, which will be described in detail below, with the lens array 120 to expand the depth of focus of the virtual stereoscopic image displayed in the air and reduce blurring of the stereoscopic image.

[0035] Here, the principle of light field display by the light field display 100 of this embodiment will be explained in detail using Figures 2 to 19. As shown in Figure 1, if the focal length of the lens array 120 is f, the distance between the lens array 120 and the flat panel display 110 is g, and the distance at which light rays from the pixels 111 of the flat panel display 110 are imaged by the lens 121 of the lens array 120 is s, then the imaging relationship 1 / g + 1 / s = 1 / f holds. Similarly, in the explanatory diagrams shown in Figures 2 to 6, the focal length of the lens array is f, the distance between the lens array and the flat panel display is g, and the distance at which light rays from the pixels of the flat panel display are imaged by the lens is s.

[0036] In flat-panel light field displays, there are three types of imaging methods for the lens array used in the flat-panel display: infinity imaging, real image imaging, and virtual image imaging, as shown in Figures 2 to 4. Figure 2 is a diagram illustrating the imaging of light rays in an infinity imaging type light field display. Figure 3 is a diagram illustrating the imaging of light rays in a real image imaging type light field display. Figure 4 is a diagram illustrating the imaging of light rays in a virtual image imaging type light field display.

[0037] Infinity imaging occurs when g=f. In this case, s=∞, and the pixels of the flat panel display are imaged at infinity, resulting in an infinite magnification. Therefore, the pixels are magnified infinitely, and as shown in Figure 2, the image of one pixel is observed through one lens of the lens array. Consequently, the number of resolution points of the stereoscopic image is equal to the number of lenses in the lens array.

[0038] Figure 5 is a diagram illustrating the ray divergence at infinity. As shown in Figure 5, a ray emitted from a single pixel diverges at an angle φ corresponding to the pixel width after passing through the lens. inf It has this characteristic. Therefore, the three-dimensional image will have blurring corresponding to the angle of light ray spread. The pixel width is w p Expressed as φ, the angle of ray divergence is φ inf = 2tan-1 (w p is given by (w / 2f). Since the spread of the light beam causes blurring of the stereoscopic image, the blurring of the stereoscopic image is minimized at the position of the lens array and increases as the distance from the lens array increases.

[0039] Next, the cases of real image formation and virtual image formation will be described. In this case, g≠f, and the image of the pixel is formed at a finite distance. Real image formation is the case where g>f. In real image formation, it is often done to make the width of the real image of the pixel less than or equal to half of the lens pitch. In this case, as shown in FIG. 3, real images of two or more pixels can be seen through the lens, and the resolution of the stereoscopic image can be made 2×2 times or more the number of lenses in the lens array. The spread of the light beam in this case is shown in FIG. 6. The spread of the light emitted from one pixel is minimized at the image formation position of the real image. Therefore, the blurring of the stereoscopic image is minimized at the image formation position. The spread angle φ of the light beam before and after the real image real is, φ real =2tan -1 {[p l / 2+(w p s / g) / 2] / s}. Using w p <p l and the imaging formula 1 / g + 1 / s = 1 / f, it can be shown that φ real >φ inf . Therefore, in real image formation, the blurring of the stereoscopic image is larger than that in infinite focus imaging. That is, when real image formation is used for stereoscopic display, the resolution of the stereoscopic image can be increased, but the blurring in the depth direction of the stereoscopic image increases. This can be similarly shown for the case of virtual image formation.

[0040] Real-image light field displays are used in stationary and portable stereoscopic displays. They are particularly effective for displaying aerial images because they can project a stereoscopic image at a distance from the display surface. Virtual-image light field displays are used in head-mounted displays and near-eye displays. They can project a virtual image at a distance of approximately 1 meter behind a lens array with a short focal length. Since the depth of the display device is approximately the focal length of the lens array, this is effective for miniaturization. Furthermore, in both cases, it is known that increasing the number of pixels corresponding to one lens in the lens array and thereby increasing the light density can reduce visual fatigue during stereoscopic image observation.

[0041] In semiconductor lithography equipment and microscopes, techniques are used to improve image resolution and expand depth of field by manipulating the shape of the pupil function using the transmittance distribution of optical elements attached to the imaging lens, or by controlling the light distribution at the imaging lens through modifications to the illumination optical system to effectively control the shape of the pupil function.

[0042] Figure 7 shows an example of an imaging system. In an incoherent imaging system, the intensity distribution of the Fourier transform of the lens pupil function gives the point image response function, and the convolution of the intensity distribution of the input image and the point image response function gives the intensity distribution of the output image. Figure 8 shows an example of the pupil function of a circular aperture in the XY plane. In the example of Figure 7, as shown in Figure 8, the circular aperture, which is the lens shape, becomes the pupil function.

[0043] Figure 9 shows the amplitude distribution in the X-axis direction of the Fourier transform image of the pupil function of a circular aperture. Figure 10 shows the intensity distribution in the X-axis direction of the Fourier transform image of the pupil function of a circular aperture. Figure 11 shows the intensity distribution in the XY plane of the Fourier transform image of the pupil function of a circular aperture. The intensity distribution of the Fourier transform image is the point image response function, and its cross-section is shown in Figure 10, while its two-dimensional distribution is shown in Figure 11. This is a distribution called the Airy image.

[0044] Figure 12 shows an example of the pupil function of an annular aperture in the XY plane. In semiconductor exposure equipment and microscopes, an annular aperture with the center shielded is used as the pupil function, as shown in Figure 12. The annular aperture can be represented as a distribution obtained by subtracting a small circular aperture from a large circular aperture.

[0045] Figure 13 shows the amplitude distribution in the X-axis direction of the Fourier transform image of the pupil function of an annular aperture. The Fourier transform of a large circular aperture has a small spread, and the Fourier transform of a small circular aperture has a large spread. Therefore, the Fourier transform of an annular aperture has a distribution obtained by subtracting the large spread from the small spread, as shown in Figure 13.

[0046] Figure 14 shows the intensity distribution in the X-axis direction of the Fourier transform image of the pupil function of an annular aperture. Figure 15 shows the intensity distribution in the XY plane of the Fourier transform image of the pupil function of an annular aperture. The intensity distribution of the Fourier transform image is the point image response function, and Figure 14 shows its cross-section, while Figure 15 shows its two-dimensional distribution. In this case, the point image response function given by the pupil function of an annular aperture has a smaller width than the point image response function given by the pupil distribution of a circular aperture. Therefore, using the pupil function of an annular aperture improves the resolution of the output image. However, in the case of an annular aperture, the side lobes around the main lobe of the point image response function are larger compared to the case of a circular aperture, so the image quality of the output image is reduced. The subtraction of the Fourier transforms of the two circular apertures results in zero points in the point image response function, but the occurrence of these zero points is maintained over a wide range before and after the imaging plane, thus having the effect of suppressing the spreading of the point image response function light in the optical axis direction. The range in front of and behind the image plane where blurring is minimal is called the depth of field, and the pupil function of the annular aperture has the effect of widening the depth of field.

[0047] To demonstrate the effect of the pupil function of an annular aperture, a computer simulation was performed for a real-image-forming light field display. In the simulation, the focal length f of the lens was set to 10 mm and the diameter of the lens to 2 mm. The image distance s between the lens and the real image was set to 20 mm, and the object distance g between the lens and the object was set to 20 mm, resulting in 1:1 magnification. A line pattern was used as the object, with a line width of 3 mm and a line pitch of 6 mm. The wavelength of light was set to 0.5 μm.

[0048] Figure 16 shows the point image response functions in the XY plane at 0.1 mm intervals within a distance range of 19.6 to 20.4 mm from the lens in the Z-axis direction, for the cases where (a) a circular aperture and (b) an annular aperture are used as the pupil function. Figure 17 shows the change in intensity of the point image response function in the Y-axis direction with respect to distance in the Z-axis direction when a circular aperture is used as the pupil function. Figure 18 shows the change in intensity of the point image response function in the Y-axis direction with respect to distance in the Z-axis direction when an annular aperture is used as the pupil function. The units of the numerical values ​​shown on the horizontal and vertical axes of Figures 17 and 18 are [mm].

[0049] Referring to Figures 16 to 18, it can be seen that when an annular aperture is used as the pupil function, the spread of the point image response function in the XY plane at the real image formation position (20.0 mm) is smaller compared to when a circular aperture is used as the pupil function, and the intensity of the point image response function in the XY plane is maintained over a wider range before and after the real image formation position in the Z axis direction. In the simulation, Fresnel diffraction was used for diffraction calculations as an incoherent imaging method.

[0050] Figure 19 shows images in the XY plane at 0.1 mm intervals within a distance range of 19.6 to 20.4 mm from the lens in the Z-axis direction, for the cases where (a) a circular aperture and (b) an annular aperture are used as the pupil function. As shown in Figure 19, simulation results of the differences in images due to the pupil function show that with (a) a circular aperture, the contrast of the line pattern is low even at the real image formation position (20.0 mm), and the image becomes blurred as the distance from the real image formation position in the Z-axis direction increases.

[0051] In contrast, (b) with the annular aperture, the contrast of the line pattern at the real image formation position (20.0 mm) is improved, and the blurring at positions away from the real image formation position in the Z-axis direction is reduced. Thus, it can be seen that using the annular aperture as the pupil function increases the image resolution and expands the depth of field.

[0052] As described above, the head-mounted display 10 of this embodiment reduces blurring in the stereoscopic image by utilizing a virtual image-forming type light field display using a light field display 100. More specifically, as can be understood from the principle of the light field display explained using Figures 2 to 19, in the flat panel type light field display 100 of this embodiment, an aperture 135 with a predetermined pupil function corresponding to each lens 121 of the lens array 120 is displayed at each aperture 131 of the transmissive display 130 arranged adjacent to the lens array 120, thereby expanding the depth of focus of the image of the pixels 111 of the flat panel display 110 and reducing blurring in the stereoscopic image.

[0053] The aperture 135 of the predetermined pupil function described above, which expands the depth of focus of the image, will be described in detail below using computational simulations of several embodiments in a virtual image-forming type light field display 100. In this embodiment, as shown in Figure 1, g ≤ f.

[0054] In the simulation, considering the application of the light field display 100 to the head-mounted display 10, the focal length f of each lens 121 in the lens array 120 was set to 10 mm, and the diameter of each lens 121 was set to 2 mm. The image distance s between lens 121 and the virtual image was set to -400 mm, and the object distance g between lens 121 and the object, i.e., between lens 121 and the pixels 111 of the flat panel display 110, was set to 9.76 mm. The negative value of the image distance s means that the virtual image is formed behind lens 121, i.e., in the negative Z-axis direction relative to lens 121. Pixel 111 is a color pixel, and the shape of the color pixel is 12.5 × 4.3 μm 2 The rectangle was set. The wavelength of light was set to 0.5 μm. The eye observing the virtual stereoscopic image was assumed to be located 50 mm away from lens 121 in the Z-axis direction.

[0055] At least one aperture 135 in each aperture 131 of the transmissive display 130 has an area smaller than the area of ​​the corresponding lens 121 among the multiple lenses 121 of the lens array 120 in the XY plane, i.e., in a planar view. In a planar view, the area of ​​at least one aperture 135 in each aperture 131 is, for example, 80% or less of the area of ​​the corresponding lens 121.

[0056] At least one opening 135 in each opening 131 further has one of the shapes of a circle, an ellipse, or a polygon in plan view. In each embodiment of this specification, as an example, each opening 131 is described as including at least one circular opening 135 in plan view.

[0057] Figure 20 is a diagram illustrating a virtual image-forming type light field display 100 according to the first embodiment of this embodiment, in which at least one aperture 135 included in each aperture 131 of the transmissive display 130 is a single annular aperture. Figure 21 is a diagram illustrating a virtual image-forming type light field display 100 according to the second embodiment of this embodiment, in which at least one aperture 135 included in each aperture 131 of the transmissive display 130 is four small-diameter circular apertures arranged vertically and horizontally. Figure 22 is a diagram illustrating a virtual image-forming type light field display 100 according to the third embodiment of this embodiment, in which at least one aperture 135 included in each aperture 131 of the transmissive display 130 is a single small-diameter circular aperture smaller in diameter than the lens 121 of the lens array 120. In Figures 20 to 22, a dashed straight line extending horizontally is shown in the middle of the vertical direction in the figures. Figures 20 to 22 show a schematic side view of the light field display 100 above the line, and an enlarged schematic XY plan view of the lens array 120 and the transmissive display 130 in the light field display 100 below the line.

[0058] As in the light field display 100 of the first embodiment shown in Figure 20, each aperture 131 of the transmissive display 130 may include at least one circular annular aperture 135, the center of which coincides with the optical axis of the corresponding lens 121 of the lens array 120 and which is shielded from light.

[0059] As shown in the light field display 100 of the second embodiment in Figure 21, each aperture 131 of the transmissive display 130 may include, as at least one aperture 135, four circular small-diameter apertures that are equally spaced from each other around the optical axis of the corresponding lens 121 of the lens array 120 in a plan view, and each has a radius of 1 / (1+√2) times or less the radius of the corresponding lens 121. That is, if the radius of the corresponding lens 121 is r, the maximum radius of each of the four circular small-diameter apertures may be r / (1+√2). The above-mentioned 1 / (1+√2) times or less may correspond to 41.4% or less. In the following description, these four circular small-diameter apertures may be collectively referred to as deformed apertures.

[0060] As shown in the third embodiment of the light field display 100 in Figure 22, each aperture 131 of the transmissive display 130 may include at least one small-diameter circular aperture as an aperture 135, the center of which coincides with the optical axis of the corresponding lens 121 of the lens array 120, and which has an area of ​​less than half the area of ​​the corresponding lens 121 in a plan view. In this specification, the single small-diameter circular aperture in the third embodiment may be referred to as a small-diameter circular aperture.

[0061] Figure 23 is a diagram illustrating a virtual image-forming type light field display according to a comparative example. In Figure 23, as in Figure 20, a dashed line extending horizontally is shown in the middle of the vertical direction of the figure. Above this line is a schematic side view showing the outline of the light field display, and below this line is an enlarged schematic XY plan view of the lens array and the pupil function of the lens array in the light field display. Unlike the light field display 100 of this embodiment, the light field display of the comparative example does not have an aperture array like the transmissive display 130. Therefore, in the light field display of the comparative example, the lenses of the lens array themselves become the pupil function, and the pupil function is a circular aperture with the same diameter as the lens diameter.

[0062] The simulation results of the first to third embodiments of this embodiment shown in Figures 20 to 22 and the simulation results of the comparative example shown in Figure 23 will be compared and explained using Figures 24 to 46. In the first embodiment of this embodiment shown in Figure 20, the outer diameter of each ring opening was 1.7 mm and the inner diameter was 0.5 mm. In the second embodiment of this embodiment shown in Figure 21, the diameter of each deformed opening, i.e., the four small-diameter openings, was 0.6 mm. In the third embodiment of this embodiment shown in Figure 22, the diameter of each small-diameter opening was 1.0 mm. In the comparative example shown in Figure 23, the diameter of each circular opening is 2 mm, the same as the diameter of each lens 121 of the lens array 120.

[0063] Figure 24 shows the change in the point image response function in the Y-axis direction with respect to distance in the Z-axis direction in a comparative example. Figure 25 shows the change in intensity of the point image response function in the Y-axis direction with respect to distance in the Z-axis direction in the first embodiment of this model. Figure 26 shows the change in intensity of the point image response function in the Y-axis direction with respect to distance in the Z-axis direction in the second embodiment of this model. Figure 27 shows the change in intensity of the point image response function in the Y-axis direction with respect to distance in the Z-axis direction in the third embodiment of this model. The units of the numerical values ​​shown on the horizontal and vertical axes of Figures 24 to 27 are [mm].

[0064] In the comparative example light field display, as shown in Figure 24, a strong intensity distribution is obtained in the range of approximately -440 mm to -360 mm, centered around the virtual image formation position of -400 mm. In contrast, in the first embodiment of the light field display 100 of this embodiment, as shown in Figure 25, a strong intensity distribution is obtained in the range of approximately -470 mm to -320 mm, centered around the virtual image formation position of -400 mm. This shows that the range in which the point image response function has strong intensity is expanded compared to the comparative example.

[0065] According to the light field display 100 of the second embodiment of this present invention, as shown in Figure 26, a strong intensity distribution is obtained in the range of approximately -480 mm to -320 mm, centered around the virtual image formation position of -400 mm. Compared to the comparative example, it can be seen that the range in which the point image response function has strong intensity is expanded. However, in the second embodiment, the side lobes are larger compared to the comparative example.

[0066] According to the light field display 100 of the third embodiment of this model, as shown in Figure 27, a strong intensity distribution is obtained over a wider range than at least -520 mm to -320 mm, centered around the virtual image formation position of -400 mm. Compared to the comparative example, the range in which the point image response function has strong intensity is expanded.

[0067] Next, we calculated the virtual image when multiple pixels emitted light. We assumed that 3 × 6 color pixels emitted light in a checkerboard pattern. Figure 28 shows the images in the XY plane at 40 mm intervals within a distance range of -520 to -320 mm from the lens in the Z-axis direction, for each of the following cases: (a) circular aperture of the comparative example, (b) annular aperture of the first embodiment, (c) deformed aperture of the second embodiment, and (d) small-diameter circular aperture of the third embodiment, used as pupil functions.

[0068] In the comparative example light field display, as shown in Figure 28(a), a sharp image is obtained around -400 mm, which is the virtual image formation position, and the blurring of the image increases as the distance from this position increases. In contrast, in the first embodiment of this light field display 100, as shown in Figure 28(b), compared to the comparative example, the image is sharper and less blurred at positions far from the virtual image formation position, and the depth of focus of the stereoscopic image is expanded.

[0069] As shown in Figure 28(c), the light field display 100 of the second embodiment of this model also shows that, compared to the comparative example, the image is sharper and blurring is reduced at positions far from the virtual image formation position, and the depth of field of the stereoscopic image is expanded. However, in the second embodiment, the contrast is slightly reduced around -400 mm, which is the virtual image formation position, compared to the comparative example.

[0070] In the third embodiment of the light field display 100 of this embodiment, as shown in Figure 28(d), the change in blur depending on the distance from the virtual image formation position is smaller compared to the comparative example, and it can be seen that the depth of focus of the stereoscopic image is expanded. However, in the third embodiment, the resolution of the stereoscopic image is slightly lower compared to the comparative example.

[0071] Each image shown in Figure 28 is shown in enlarged view from Figures 29 to 42. Figure 29 shows enlarged views of the comparative example light field display at a Z coordinate position of -440 mm and at a Z coordinate position of -480 mm. In the comparative example, the image at a Z coordinate position of -480 mm is significantly more blurred than the image at a Z coordinate position of -440 mm, indicating that one boundary of the range in which the point image response function in the Z axis direction has a strong intensity is around -440 mm.

[0072] Figure 30 shows magnified images of the light field display 100 at a Z coordinate position of -440 mm and at a Z coordinate position of -480 mm for the first embodiment of this embodiment. Figure 31 shows magnified images of the light field display 100 at a Z coordinate position of -440 mm and at a Z coordinate position of -480 mm for the second embodiment of this embodiment. Figure 32 shows magnified images of the light field display 100 at a Z coordinate position of -440 mm and at a Z coordinate position of -480 mm for the third embodiment of this embodiment. In the first to third embodiments of this embodiment, the image at a Z coordinate position of -480 mm shows almost no change in blurring compared to the image at a Z coordinate position of -440 mm, and it can be seen that one boundary of the range in which the point image response function in the Z axis direction has a strong intensity is a position further from the virtual image formation position than the Z coordinate position of -480 mm. In other words, according to the first to third embodiments of this embodiment, it can be seen that the depth of focus of the stereoscopic image is expanded compared to the comparative example.

[0073] Figure 33 shows magnified images of the comparative example light field display at a Z coordinate position of -360 mm and at a Z coordinate position of -320 mm. In the comparative example, the image at a Z coordinate position of -320 mm is significantly more blurred than the image at a Z coordinate position of -360 mm, indicating that the other boundary of the range in which the point image response function in the Z axis direction has a strong intensity is around -360 mm.

[0074] Figure 34 shows magnified images of the light field display 100 at a Z coordinate position of -360 mm and at a Z coordinate position of -320 mm for the first embodiment of this embodiment. Figure 35 shows magnified images of the light field display 100 at a Z coordinate position of -360 mm and at a Z coordinate position of -320 mm for the second embodiment of this embodiment. Figure 36 shows magnified images of the light field display 100 at a Z coordinate position of -360 mm and at a Z coordinate position of -320 mm for the third embodiment of this embodiment. In the first to third embodiments of this embodiment, the image at a Z coordinate position of -320 mm shows almost no change in blurring compared to the image at a Z coordinate position of -360 mm, and it can be seen that the other boundary of the range in which the point image response function in the Z axis direction has a strong intensity is a position further from the virtual image formation position than the Z coordinate position of -360 mm. In other words, according to the first to third embodiments of this embodiment, it can be seen that the depth of focus of the stereoscopic image is expanded compared to the comparative example.

[0075] Figure 37 shows, side by side and enlarged, (a) an image of the Z coordinate position at -480 mm using a circular aperture of the comparative example and (b) an image of the Z coordinate position at -480 mm using an annular aperture of the first embodiment. It can be seen that, according to the first embodiment of this example, the image at the Z coordinate position at -480 mm has higher contrast compared to the comparative example.

[0076] Figure 38 shows, side by side and enlarged, (a) the image at the Z coordinate position of -480 mm using a circular aperture of the comparative example and (c) the image at the Z coordinate position of -480 mm using a deformed aperture of the second embodiment. It can be seen that, even with the second embodiment of this present invention, the image at the Z coordinate position of -480 mm is brighter compared to the comparative example.

[0077] Figure 39 shows, side by side and enlarged, (a) an image of the Z coordinate position at -480 mm using a circular aperture of the comparative example and (c) an image of the Z coordinate position at -480 mm using a small-diameter circular aperture of the third embodiment. It can be seen that, even with the third embodiment of this present invention, the image at the Z coordinate position at -480 mm has higher contrast compared to the comparative example.

[0078] Figure 40 shows, side by side and enlarged, (a) an image of the Z coordinate position at -320 mm using a circular aperture of the comparative example and (b) an image of the Z coordinate position at -320 mm using an annular aperture of the first embodiment. It can be seen that, according to the first embodiment of this model, the image at the Z coordinate position at -320 mm is sharper and less blurred compared to the comparative example.

[0079] Figure 41 shows, side by side and enlarged, (a) the image at the Z coordinate position of -320 mm using a circular aperture of the comparative example and (c) the image at the Z coordinate position of -320 mm using a deformed aperture of the second embodiment. It can be seen that, even with the second embodiment of this present invention, the image at the Z coordinate position of -320 mm is sharper and less blurred compared to the comparative example.

[0080] Figure 42 shows, side by side and enlarged, (a) the image at the Z coordinate position of -320 mm using a circular aperture of the comparative example and (c) the image at the Z coordinate position of -320 mm using a small-diameter circular aperture of the third embodiment. It can be seen that, even with the third embodiment of this present invention, the image at the Z coordinate position of -320 mm is sharper and has less blur compared to the comparative example.

[0081] Figure 43 shows the intensity distribution in the X-axis direction of the point image response function at the observation position described above for the comparative example light field display. Figure 44 shows the intensity distribution in the X-axis direction at the observation position described above for the light field display 100 of the first embodiment of this embodiment. Figure 45 shows the intensity distribution in the X-axis direction at the observation position described above for the light field display 100 of the second embodiment of this embodiment. Figure 46 shows the intensity distribution in the X-axis direction at the observation position described above for the light field display 100 of the third embodiment of this embodiment. The units of the numerical values ​​shown on the horizontal axis in Figures 43 to 46 are [mm], and the units of the numerical values ​​shown on the vertical axis are arbitrary constants.

[0082] Within the intensity distributions shown in Figures 43 to 46, pixels corresponding to the point image response function will be observed. In a flat panel display, pixels are arranged periodically, so the pixel images are also arranged periodically at the observation position. The interval is given by (pixel pitch of the flat panel display) × (distance between the flat panel display and the observation position) / (distance between the flat panel display and the lens array), which is 64.0 μm in the horizontal direction under the simulation conditions. Except for the intensity distribution of the small-diameter circular aperture shown in Figure 46, the spread of the point image response function is 120 μm or more, corresponding to the image of two or more pixels, so two or more pixels are seen by the eye simultaneously. This corresponds to the fact that in virtual image formation, images of multiple pixels are observed through the lens, improving the resolution of the stereoscopic image. In contrast, in the small-diameter circular aperture of Figure 46, the spread of the point image response function is about 80.0 μm, corresponding to the image of about one pixel, so about one pixel is seen by the eye simultaneously through the lens. Therefore, when a small-diameter circular aperture is used as the pupil function, as in the third embodiment, the depth of focus of the stereoscopic image is expanded and blurring is reduced, but the effect of improving the resolution of the stereoscopic image due to virtual image formation may be reduced.

[0083] According to the light field display 100 of the first embodiment described above, the depth of focus of the image of the pixels 111 of the flat panel display 110 can be increased, thereby reducing blurring in the stereoscopic image.

[0084] In the light field display 100 according to the first embodiment, the transmissive display 130 may change the shape of at least one aperture 135 of each aperture 131 over time. For example, the transmissive display 130 may alternately display the aforementioned annular aperture and small-diameter circular aperture in each aperture 131. Such a transmissive display 130 would use a relatively high-speed display, but the display of the flat panel display 110 may be at a normal video rate. By operating the transmissive display 130 in this way, the light field display 100 can simultaneously achieve the effects of improving the resolution of the stereoscopic image and expanding the depth of field.

[0085] In the light field display 100 according to the first embodiment, the transmissive display 130 may vary the shape of at least one aperture 135 of each aperture 131 depending on its location, that is, depending on the position of the multiple apertures 131 in the XY plane. For example, the transmissive display 130 may display either the annular aperture or the small-diameter circular aperture in each aperture 131 depending on the position of each aperture 131 in the XY plane. By operating the transmissive display 130 in this manner, the light field display 100 may be able to simultaneously obtain locations where the resolution of the stereoscopic image is improved and locations where the depth of field is expanded.

[0086] Figure 47 is a schematic side view showing an outline of the head-mounted display 11 according to the second embodiment. The head-mounted display 11 according to the second embodiment differs from the head-mounted display 10 according to the first embodiment in that it additionally includes an eyepiece lens 30. Other components of the head-mounted display 11 according to the second embodiment are the same as the corresponding components of the head-mounted display 10 according to the first embodiment, so the same reference numerals as in the head-mounted display 10 according to the first embodiment are used, and redundant explanations are omitted.

[0087] The eyepiece 30 is located within the housing 20, on the side of the eye of the person observing the virtual three-dimensional image, and further forms a virtual image of the virtual three-dimensional image displayed by the head-mounted display 11 using a light field. The head-mounted display 11 according to the second embodiment has the same effects as the head-mounted display 10 according to the first embodiment. The head-mounted display 11 according to the second embodiment can further widen the field of view by additionally providing such an eyepiece 30. Furthermore, by using the configuration shown in Figure 47 for the left and right eyes, the lens diameter of the eyepiece 30 can be reduced, making it easier to manufacture the eyepiece 30. Note that in other embodiments of virtual image forming type head-mounted displays in this specification, the eyepiece 30 may also be applied in the same way as in this embodiment, and in this case, the same effects as in this embodiment will be achieved.

[0088] Figure 48 is a schematic side view showing an outline of the head-mounted display 12 according to the third embodiment. The head-mounted display 12 according to the third embodiment differs from the head-mounted display 10 according to the first embodiment in that, in the light field display 102, the flat panel display 110, the transmissive display 130, and the lens array 120 are arranged in this order in the Z-axis direction. Other components of the head-mounted display 12 according to the third embodiment are the same as the corresponding components of the head-mounted display 10 according to the first embodiment, so the same reference numbers as in the head-mounted display 10 according to the first embodiment are used and redundant explanations are omitted. The head-mounted display 12 according to the third embodiment, equipped with the light field display 102 configured in this way, also has the same effects as the head-mounted display 10 according to the first embodiment.

[0089] Figure 49 is a schematic plan view showing a lens array 220 and a transmissive display 230, which are modified versions of the lens array 120 and transmissive display 130 in the first embodiment. As shown in Figure 49, the multiple lenses 221 of the lens array 220 and the multiple apertures 231 of the transmissive display 230 may be arranged in a honeycomb pattern two-dimensionally. As an example, Figure 49 shows a configuration in which each aperture 231 includes at least one annular aperture as an aperture 235. The lens array 220 and transmissive display 230 shown in Figure 49 are applicable to the light field displays 100, 102, etc., according to the multiple embodiments described above. The transmissive display 230 is also an example of an aperture array.

[0090] Figure 50 is a schematic side view showing an outline of the head-mounted display 13 according to the fourth embodiment. The head-mounted display 13 according to the fourth embodiment differs from the head-mounted display 10 according to the first embodiment in that it includes a light field display 103 having a fixed mask pattern 330 instead of a light field display 100 having a transmissive display 130. Other components of the head-mounted display 13 according to the fourth embodiment are the same as the corresponding components of the head-mounted display 10 according to the first embodiment, so the same reference numerals as in the head-mounted display 10 according to the first embodiment are used, and redundant explanations are omitted.

[0091] The fixed mask pattern 330 is an example of the aperture array described above and, like the transmissive display 130, has a plurality of apertures 331, each containing at least one aperture 335. The pupil function of at least one aperture 335 contained in each aperture 331 is formed in the same way as the pupil function of at least one aperture 131 contained in each aperture 131 of the transmissive display 130. The fixed mask pattern 330 may be formed integrally with the lens array 120, as shown in Figure 50, or it may be formed separately from the lens array 120 and positioned adjacent to the lens array 120. The head-mounted display 13 of the fourth embodiment, which includes a light field display 103 configured in this way, also has the same effects as the head-mounted display 10 of the first embodiment.

[0092] In the multiple embodiments described above, virtual image-forming type light field displays were described. However, even if a real image-forming type light field display has the same configuration as the virtual image-forming type light field display, that is, if the arrangement is changed in the virtual image-forming type light field display so that g > f, and the aerial image is displayed as a light field on the observer's side, it will have the same effect as the light field display of the first embodiment and the like.

[0093] Although the present invention has been described above using embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications or improvements can be made to the above embodiments. It will be clear from the claims that such modified or improved forms may also be included in the technical scope of the present invention.

[0094] It should be noted that the execution order of operations, procedures, steps, and stages in the apparatus, systems, programs, and methods shown in the claims, specifications, and drawings is not explicitly stated as "before," "prior to," etc., and that these can be implemented in any order unless the output of a previous process is used in a later process. Even if the operation flow in the claims, specifications, and drawings is described using phrases such as "first," "next," etc. for convenience, it does not mean that it is essential to perform the operations in that order. [Explanation of Symbols]

[0095] 10 Head-mounted displays 20 cabinets 100 Light Field Displays 110 Flat Panel Display 111 pixels 120 lens array 121 Lens 130 Transparent Display 131 Opening 135 Aperture 11. Head-mounted display 30 eyepieces 12 Head-mounted displays 102 Light Field Display 220 lens array 221 Lens 230 Transparent Display 231 Opening 235 Aperture 13. Head-mounted display 103 Light Field Display 330 Fixed Mask Patterns 331 Opening 335 Aperture

Claims

1. A flat-panel type light field display comprising a flat panel display, a lens array, and an aperture array arranged in one direction, The flat panel display has a plurality of pixels arranged in two dimensions, The lens array has a plurality of lenses arranged in two dimensions, and each of the plurality of lenses images a light ray emitted from a group of pixels consisting of a plurality of pixels arranged adjacent to each other in the flat panel display. The aperture array is positioned adjacent to the lens array and has a plurality of apertures arranged two-dimensionally to correspond one-to-one with the plurality of lenses, and each of the plurality of apertures includes at least one aperture of a circular, elliptical, or polygonal shape having an area smaller than the area of ​​the corresponding lens among the plurality of lenses in a plan view. Light field display.

2. The aperture array is a transmissive display in which the shape of at least one of the apertures is electronically controllable. The light field display according to claim 1.

3. The transparent display changes the shape of at least one of the openings in each of the openings over time. The light field display according to claim 2.

4. The transmissive display alternately displays, in each of the apertures, a circular annular aperture whose center coincides with the optical axis of the corresponding lens and whose center is shielded from light, and a circular small-diameter aperture whose center coincides with the optical axis of the corresponding lens and whose area in a plan view is less than half the area of ​​the corresponding lens. The light field display according to claim 3.

5. The transparent display makes the shape of at least one of the openings of each opening different depending on its position in the two-dimensional plane in which the plurality of openings are arranged. The light field display according to claim 2.

6. The transmissive display displays, depending on the position of each opening in the plane, a circular annular opening whose center coincides with the optical axis of the corresponding lens and whose center is shielded from light, or a circular small-diameter opening whose center coincides with the optical axis of the corresponding lens and whose area in a plan view is less than or equal to half the area of ​​the corresponding lens. The light field display according to claim 5.

7. The plurality of pixels of the flat panel display are arranged in one direction closer to the lens array than the focal plane of the lens array, thereby displaying a virtual three-dimensional image in the air. The light field display according to claim 1.

8. A head-mounted display comprising the light field display described in claim 7.

9. A head-mounted display comprising a light field display as described in claim 7, and a lens that further forms a virtual image of the virtual image thereof.

10. In a plan view, the area of ​​at least one of the openings is 80% or less of the area of ​​the corresponding lens. The light field display according to claim 1.

11. Each of the aforementioned openings includes a circular annular opening whose center coincides with the optical axis of the corresponding lens and whose center is shielded from light. The light field display according to claim 1.

12. Each of the aforementioned openings includes four small circular apertures, which, in a plan view, are positioned at equal intervals from each other around the optical axis of the corresponding lens and each has a radius of no more than 1 / (1+√2) times the radius of the corresponding lens. The light field display according to claim 1.

13. Each of the aforementioned openings includes a single circular small-diameter opening whose center coincides with the optical axis of the corresponding lens and whose area in a plan view is less than or equal to half the area of ​​the corresponding lens. The light field display according to claim 1.

14. The flat panel display, the aperture array, and the lens array are arranged in this order in the aforementioned one direction. The light field display according to claim 1.

15. The flat panel display, the lens array, and the aperture array are arranged in this order in the aforementioned one direction. The light field display according to claim 1.

16. The plurality of lenses in the lens array and the plurality of apertures in the aperture array are arranged orthogonally in two dimensions. The light field display according to claim 1.

17. The plurality of lenses in the lens array and the plurality of apertures in the aperture array are arranged in a honeycomb pattern in two dimensions. The light field display according to claim 1.

Images