Method for manufacturing a diffraction sheet

Abstract

A three-dimensional display device includes a diffraction sheet (1) having a diffraction layer including a first diffraction pattern arranged in a first arrangement pattern on a transparent substrate and a second diffraction pattern arranged in a second arrangement pattern, a liquid crystal device having a plurality of pixels, and a light source. In a normal line direction of the diffraction sheet, the first diffraction pattern and the second diffraction pattern are arranged so as to overlap the pixels, and a misalignment amount is 1 / 10 or less of a pitch of the pixels.

Description

Technical Field

[0001] This invention relates to diffraction sheets and methods for manufacturing the same. It also relates to three-dimensional display devices, light reproduction devices, three-dimensional spatial display systems, light reproduction methods, and procedures incorporating the diffraction sheet.

[0002] This application claims priority to and is based on Japanese Patent Application No. 2020-139079 filed in Japan on August 20, 2020 and Japanese Patent Application No. 2020-163317 filed in Japan on September 29, 2020, the contents of which are incorporated herein by reference. Background Technology

[0003] Various techniques are known to utilize the diffraction phenomenon of light to control the direction of light and display three-dimensional images (stereoscopic images).

[0004] Patent document 1 describes a method of displaying a three-dimensional image that moves naturally without image skipping by overlaying a light-shielding mechanism such as a liquid crystal panel with a diffraction pattern.

[0005] Patent documents 2 and 3 describe a display body that displays a stereoscopic image with natural colors by arranging multiple diffraction elements such as diffraction gratings and holograms, and combining a light source, a diffraction grating unit, and a color filter.

[0006] Thus, by aligning and combining a diffraction pattern with multiple diffraction elements with a pattern arranged like a liquid crystal or color filter, it is possible to make a three-dimensional image move or to display it in full color.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 7-287192

[0010] Patent Document 2: Japanese Patent Application Publication No. 8-211821

[0011] Patent Document 3: Japanese Patent Application Publication No. 2017-219824

[0012] Patent Document 4: Japanese Patent Application Publication No. 2003-316241 Summary of the Invention

[0013] The problem that the invention aims to solve

[0014] There is a demand to use the aforementioned techniques to display larger 3D structures. However, the diffraction patterns formed by diffraction of visible light are tiny structures at the submicron level, created using electronic line drawing devices, laser drawing devices, etc. Therefore, under current conditions, the maximum size that can be formed at one time is less than 10 inches (the diagonal of a rectangle).

[0015] As a method for producing large-area diffraction patterns, Patent Document 4 describes a method for producing them using a multifaceted master plate composed of multiple unit master plates.

[0016] In multi-sided printing, there are limits to the precision required when arranging multiple unit originals; misalignment of tens to hundreds of micrometers will inevitably occur regardless. Even when repeatedly transferring unit originals while changing their positions, the same misalignment cannot be avoided.

[0017] If only a three-dimensional image is being displayed, this misalignment is permissible. However, to enable movement of the three-dimensional image or to display in full color, the diffraction pattern needs to be aligned with the arrangement patterns of the color filter and liquid crystal pixels. From the viewpoint of achieving a good display, the misalignment needs to be reduced to less than 1 / 10 of the spacing between the pixels. However, due to the aforementioned situation, the method described in Patent Document 4 is extremely difficult and almost impossible to achieve.

[0018] Furthermore, in existing technologies, in 3D display devices capable of displaying moving 3D images and color 3D images, when displaying a space with depth that allows for appropriate interpersonal distance (personal space), there is a problem that sometimes significant blurring occurs due to the effects of diffraction.

[0019] In view of the above, the object of the present invention is to provide a diffraction sheet that can achieve a high-precision diffraction pattern even over a large area.

[0020] Other objects of the present invention are to provide a large-area three-dimensional display device capable of displaying moving three-dimensional images and colored three-dimensional images, as well as a light reproduction device, a three-dimensional space display system, a light reproduction method, and a program capable of displaying a three-dimensional space with a natural sense of distance and less blur when displaying a space with depth.

[0021] Methods for solving problems

[0022] The three-dimensional display device according to a first aspect of the present invention comprises: a diffraction sheet with a diagonal of 10 inches or more, having a transparent substrate, and a diffraction layer including a first diffraction pattern arranged in a first arrangement pattern and a second diffraction pattern arranged in a second arrangement pattern on the substrate; a liquid crystal device having a plurality of pixels; and any one of a color filter having two or more color filters.

[0023] In this three-dimensional display device, in the normal direction of the diffraction sheet, the first diffraction pattern and the second diffraction pattern are arranged to overlap with the pixels or color filters, and their misalignment is less than 1 / 10 of the spacing between the pixels or color filters.

[0024] The second aspect of the present invention provides a method for manufacturing a diffraction sheet comprising: step A, forming a first uncured resin layer on a transparent substrate with a diagonal width of 10 inches or more; step B, contacting a first diffraction pattern formed over a rectangular area of ​​10 inches or more diagonally across one side of a first plate with the first uncured resin layer; step C, placing a first mask having a plurality of first openings formed based on a first arrangement pattern on the first plate, and curing portions of the first uncured resin layer overlapping with the first openings by irradiation with light; step D, forming a second uncured resin layer on one side of the substrate on which the first uncured resin layer is formed; step E, contacting a second diffraction pattern, different from the first diffraction pattern, formed over a rectangular area of ​​10 inches or more diagonally across one side of a second plate with the second uncured resin layer; and step F, placing a second mask having a plurality of second openings formed based on a second arrangement pattern different from the first arrangement pattern on the second plate, and curing portions of the second uncured resin layer overlapping with the second openings by irradiation with light.

[0025] The third-order diffraction sheet of the present invention comprises: a transparent substrate; and a diffraction layer including a first diffraction pattern arranged in a first arrangement pattern on the substrate, and a second diffraction pattern arranged in a second arrangement pattern different from the first arrangement pattern on the same side of the substrate as the first diffraction pattern, the second diffraction pattern being thicker than the first diffraction pattern.

[0026] The fourth aspect of the light reproduction apparatus of the present invention reproduces light virtually emitted from a stereoscopic image when the stereoscopic image is displayed in a reproduction space. It includes a stereoscopic image display unit that displays the stereoscopic image as either a virtual image or a real image by light emitted from each element unit included in an element unit set consisting of multiple element units arranged in two dimensions corresponding to the reproduced image. The stereoscopic image display unit displays the stereoscopic image in a region in the reproduction space at a depth direction equivalent to a social distance. The size of each element in the element unit set, i.e., the element unit, and the spacing between the element units when they are arranged in two dimensions, are values ​​determined based on the degree to which the stereoscopic image displayed in the reproduction space is observed by an observer. Furthermore, the degree to which the observer observes the stereoscopic image refers to the position and range of the displayed stereoscopic image, the degree of blur permissible by the observer, etc.

[0027] According to the aforementioned light reproduction device, social distancing spaces can be displayed as three-dimensional spaces that provide a natural sense of distance and have less blurriness.

[0028] The effects of the invention

[0029] According to the above-described method of the present invention, high-precision diffraction patterns can be achieved even over large areas.

[0030] Therefore, it is possible to realize a large-area three-dimensional display device that can display moving three-dimensional images and colored three-dimensional images, as well as a light reproduction device, three-dimensional space display system, light reproduction method and program that can display a three-dimensional space with natural distance and less blur when displaying a space with depth. Attached Figure Description

[0031] Figure 1 This is a diagram illustrating a process of manufacturing a diffraction plate according to a first embodiment of the present invention.

[0032] Figure 2 It is a diagram representing one process of this manufacturing method.

[0033] Figure 3 It is a diagram representing one process of this manufacturing method.

[0034] Figure 4 It is a diagram representing one process of this manufacturing method.

[0035] Figure 5 It is a diagram representing one process of this manufacturing method.

[0036] Figure 6 It is a diagram representing one process of this manufacturing method.

[0037] Figure 7 It is a diagram representing one process of this manufacturing method.

[0038] Figure 8 It is a diagram representing one process of this manufacturing method.

[0039] Figure 9 It is a diagram representing one process of this manufacturing method.

[0040] Figure 10 It is a diagram representing one process of this manufacturing method.

[0041] Figure 11 It is a diagram representing one process of this manufacturing method.

[0042] Figure 12 This is a diagram showing the completed diffraction pattern.

[0043] Figure 13 This is a diagram showing a modified example of the diffraction plate.

[0044] Figure 14 This is a diagram showing a modified example of a diffraction plate.

[0045] Figure 15 This is a schematic diagram illustrating a diffraction plate according to a second embodiment of the present invention.

[0046] Figure 16 This is a schematic diagram illustrating the three-dimensional display device of the present invention.

[0047] Figure 17 This is a schematic diagram illustrating other examples of the three-dimensional display device of the present invention.

[0048] Figure 18 This is a block diagram illustrating the configuration of the three-dimensional spatial display system according to the third embodiment.

[0049] Figure 19 This is a diagram illustrating an example of a three-dimensional spatial display system using the third embodiment.

[0050] Figure 20 This is a block diagram illustrating the configuration of the three-dimensional spatial display system according to the fourth embodiment.

[0051] Figure 21 This is a diagram illustrating an example of a three-dimensional spatial display system using the fourth embodiment.

[0052] Figure 22 It is a characteristic graph that shows the relationship between the distance from the 3D display to the object being observed and the magnitude of the blur produced when the object is reproduced.

[0053] Figure 23 It is a characteristic graph that shows the relationship between the distance from the 3D display to the object being observed and the resolution (circle of confusion diameter) on the retina of the observer viewing the reproduced object.

[0054] Figure 24 This is a diagram illustrating an example of the relationship between the dimension d and the spacing p in a feature cell.

[0055] Figure 25 This is a diagram illustrating an example of reproducing a point object as object point A'.

[0056] Figure 26 This is a diagram showing an example of the brightness distribution of light rays (reproduced light) reproduced from element units.

[0057] Figure 27 This is a diagram illustrating an example of reproducing a point object as object point A''.

[0058] Figure 28 It means through Figure 27 The diagram shows an example of a method that reproduces multiple objects.

[0059] Figure 29 This diagram illustrates the method of calculating data for reconstructing a hologram using ray tracing.

[0060] Figure 30This is a schematic diagram illustrating the shape of the reproduced point as observed by an observer through the screen.

[0061] Figure 31 It is a schematic diagram showing that the light reproduced from the display becomes an expanded light and a blurred shape that becomes the reproduction point.

[0062] Figure 32 This is a schematic diagram used in the instruction manual to illustrate the expansion angle and size of Fraunhofer diffraction based on a circular opening.

[0063] Figure 33 This is a flowchart illustrating the processing flow performed by the three-dimensional display of the implementation method.

[0064] Figure 34 This is a block diagram illustrating the configuration of a three-dimensional spatial display system as a variation of the implementation method.

[0065] Figure 35 This is a diagram illustrating an example of a three-dimensional spatial display system that applies a variation of the implementation method.

[0066] Figure 36 This is a cross-sectional view illustrating the configuration of a conventional light field display using a microlens array.

[0067] Figure 37 This is a schematic cross-sectional view showing the configuration of a conventional static display type light field display made by overlapping liquid crystal panels. Detailed Implementation

[0068] <Diffraction Plate>

[0069] The following is for reference Figures 1 to 14 The diffraction plate of the first embodiment of the present invention will be described.

[0070] First, the manufacturing method of the diffraction plate 1 in this embodiment will be described.

[0071] As step A, such as Figure 1 As shown, an uncured resin layer (first uncured resin layer) 20 is formed on a transparent substrate 10 by layering photocurable resin. Glass and various resins can be used as the substrate 10. A typical example of a photocurable resin is an ultraviolet-curable resin, but other materials can also be used.

[0072] As step B, such as Figure 2 As shown, the first plate 100 is brought close to the uncured resin layer 20, so that the first diffraction pattern 100a formed on the first plate 100 comes into contact with the uncured resin layer 20.

[0073] The first plate 100 is a large-area transparent plate exceeding 10 inches diagonally, which can be manufactured using the technology described in Patent Document 4. For example, when the 10-inch diagonally original plates are arranged in a 3×3 pattern or transferred into a two-dimensional matrix, a first plate 100 of approximately 30 inches diagonally can be produced. The first diffraction pattern 100a is formed in a rectangular area exceeding 10 inches diagonally on one side of the first plate 100. The area formed by the first diffraction pattern 100a has approximately the same size as the diffraction sheet to be produced. The first diffraction pattern 100a has a surface shape corresponding to the intended diffraction pattern. The surface of the first diffraction pattern 100a may also have an uneven shape, for example, having multiple protrusions protruding from the substrate of the first plate 100.

[0074] In the next step C, as Figure 3 As shown, the first mask 110 is placed on the first plate 100 and irradiated with light that cures the uncured resin layer 20.

[0075] The first mask 110 has a plurality of openings (first openings) 110a formed based on a first arrangement pattern. The first arrangement pattern is, for example, an arrangement of the red filters of an RGB color filter. The first mask 110 is substantially the same as the mask used to form the color filter, and even large-area masks can be fabricated relatively easily using known methods.

[0076] In step C, the portion of the uncured resin layer 20 that overlaps with the opening 110a only when viewed from above and is exposed into the opening 110a is cured. Hereinafter, the partially cured uncured resin layer will be simply referred to as the "resin layer".

[0077] When the first version 100 and the first mask 110 are moved, and the uncured resin in the resin layer 20 is removed by cleaning or the like, as... Figure 4 As shown, a first diffraction pattern 21, which is drawn as a first arrangement pattern, is formed on the substrate 10. The first diffraction pattern 21 is formed of cured resin and, when viewed from above, forms the same pattern as the opening 110a. In addition, a protrusion (surface unevenness) based on the first diffraction pattern 100a is formed on the upper surface side (the side opposite to the substrate 10) of the first diffraction pattern 21. In the first diffraction pattern 21, the portion in contact with the substrate 10 and the protrusion formed on the upper surface side may also be integrally formed of the same type of resin.

[0078] Furthermore, the openings mentioned in this specification refer to the portions through which light is transmitted. Therefore, it is not necessary for the mask to have holes (spaces).

[0079] In the next step D, a photocurable resin is disposed on the side of the substrate 10 where the first diffraction pattern 21 is formed, and as shown in the figure. Figure 5An uncured resin layer (second uncured resin layer) 20A is formed as shown. The photocurable resin constituting this uncured resin layer 20A may be the same as or different from the resin used in step A. The uncured resin layer 20A may also cover part or all of the first diffraction pattern 21.

[0080] In the next step E, as Figure 6 As shown, the second version 200 is brought close to the uncured resin layer 20A, so that the second diffraction pattern 200a formed on the second version 200 comes into contact with the uncured resin layer 20A.

[0081] The second version 200 is a transparent plate of the same size as the first version 100. The second diffraction pattern 200a is a different diffraction pattern from the first diffraction pattern 100a, and is formed in a rectangular area of ​​more than 10 inches diagonally on one side of the second version 200.

[0082] In the next step F, as Figure 7 As shown, the second mask 210 is placed on the second version 200 and irradiated with light that cures the uncured resin layer 20A.

[0083] The second mask 210 has a plurality of openings (second openings) 210a formed based on a second arrangement pattern that is different from the first arrangement pattern. The second arrangement pattern is, for example, an arrangement of green filters of an RGB color filter.

[0084] In step F, the portion of the uncured resin layer 20A that overlaps with the opening 210a only when viewed from above and is exposed into the opening 210a is cured. When the second plate 200 and the second mask 210 are moved, and the uncured resin in the resin layer 20A is removed by cleaning or the like, as... Figure 8 As shown, a second diffraction pattern 22, which is drawn as a second arrangement pattern, is formed on the substrate 10. At this time, part or all of the uncured resin covering the first diffraction pattern 21 is also removed. The second diffraction pattern 22 is formed by cured resin and forms the same pattern as the opening 210a when viewed from above. In addition, a protrusion based on the second diffraction pattern 200a is formed on the upper surface side of the second diffraction pattern 22. In the second diffraction pattern 22, the portion in contact with the substrate 10 and the protrusion formed on the upper surface side can also be integrally formed from the same type of resin.

[0085] In the next step G, a photocurable resin is disposed on the side of the substrate 10 where the second diffraction pattern 22 is formed, and as shown in the figure. Figure 9As shown, an uncured resin layer (third uncured resin layer) 20B is formed. The photocurable resin constituting the uncured resin layer 20B can be the same as or different from the resin used in steps A and D. The uncured resin layer 20B can also cover part or all of the first diffraction pattern 21 and the second diffraction pattern 22.

[0086] As for the next step H, such as Figure 10 As shown, the third version 300 is brought close to the uncured resin layer 20B, so that the third diffraction pattern 300a formed on the third version 300 comes into contact with the uncured resin layer 20B.

[0087] The third version 300 is a transparent plate of the same size as the first version 100 and the second version 200. The third diffraction pattern 300a is a diffraction pattern that is different from either the first diffraction pattern 100a or the second diffraction pattern 200a, and is formed in a rectangular area of ​​more than 10 inches diagonally on one side of the third version 300.

[0088] In the next step I, as Figure 11 As shown, the third mask 310 is placed on the third version 300 and irradiated with light that cures the uncured resin layer 20B.

[0089] The third mask 310 has multiple openings (third openings) 310a formed based on a third arrangement pattern that is different from both the first and second arrangement patterns. The third arrangement pattern is, for example, the arrangement of the blue filter of an RGB color filter.

[0090] In step I, the portion of the uncured resin layer 20B that overlaps with the opening 310a only when viewed from above and is exposed into the opening 310a is cured. When the third version 300 and the third mask 310 are moved, and the uncured resin in the resin layer 20B is removed by cleaning or the like, as... Figure 12 As shown, a third diffraction pattern 23, which is drawn as a third arrangement pattern, is formed on the substrate 10. The third diffraction pattern 23 is formed by cured resin and forms the same pattern as the opening 310a when viewed from above. In addition, a protrusion based on the third diffraction pattern 300a is formed on the upper surface side of the third diffraction pattern 23. In the third diffraction pattern 23, the portion in contact with the substrate 10 and the protrusion formed on the upper surface side can also be integrally formed from the same type of resin.

[0091] Through the above processes, the diffraction plate 1 of this embodiment is manufactured. For example... Figure 12 As shown, the diffraction sheet 1 is configured to have a diffraction layer 30 on the substrate 10, including a first diffraction pattern 21, a second diffraction pattern 22, and a third diffraction pattern 23.

[0092] The first diffraction pattern 21, the second diffraction pattern 22, and the third diffraction pattern 23 are configured with high precision based on the first, second, and third arrangement patterns, respectively, when viewed from above the diffraction sheet 1. Therefore, by aligning and mounting these patterns simultaneously in a color filter with color filters arranged based on the first, second, and third arrangement patterns, or in a liquid crystal device having a liquid crystal layer and a driving substrate with pixels of the same size as openings 110a, 210a, and 310a, it is possible to make each diffraction pattern 21, 22, and 23 coincide with the color filters and pixels in the normal direction of the diffraction sheet 1, and suppress their misalignment to less than 1 / 10 of the spacing between the color filters and pixels.

[0093] According to the diffraction plate manufacturing method of this embodiment, in each of the plates (first plate 100, second plate 200, and third plate 300) used in steps B, E, and H, an undrawn full-surface diffraction pattern is used, and light is irradiated using the masks (first mask 110, second mask 210, and third mask 310) in steps C, F, and I, thereby drawing on each side. Figure 1 The uncured resin layers 20, 20A, and 20B are cured. Furthermore, by partially curing the resin while each plate is in contact with the uncured resin layer, it is possible to obtain multiple diffraction patterns 21, 22, and 23 on the upper surface side by transferring the concave and convex shapes of the diffraction patterns 100a, 200a, and 300a formed on the surface of each plate (first plate 100, second plate 200, and third plate 300).

[0094] Thus, even large areas with a diagonal diameter of 10 inches or more can form a diffraction layer 30 containing multiple diffraction patterns while achieving high drawing accuracy.

[0095] In this embodiment, an example of forming a diffraction pattern using three sets of plates and masks is described, but this is only one example. The number of times the diffraction pattern is formed can be set to two or more as desired. That is, the diffraction sheet 1 may also have only two types of diffraction patterns 21 and 22. The diffraction sheet 1 may also be overlapped with either a liquid crystal device having multiple pixels or a color filter having two or more color filters. In this case, when the first diffraction pattern 21 and the second diffraction pattern 22 are arranged to overlap with the aforementioned pixels or color filters in the normal direction of the diffraction sheet 1, the misalignment amount can be suppressed to less than 1 / 10 of the spacing between the color filters and pixels.

[0096] Thus, for example, by forming multiple slightly different patterns of the reproduced three-dimensional image each time and mounting them on a liquid crystal device, a display device is constructed, thereby enabling the display of a moving three-dimensional image.

[0097] Figure 13 The diffraction sheet 1A shown in the modified example has a color filter 40 including multiple color filters between the substrate 10 and the diffraction layer 30. The diffraction sheet 1A is manufactured by forming the color filter 40 including multiple color filters on the substrate 10 using a first mask 110, a second mask 210, and a third mask 310, and then forming the diffraction layer 30 on the color filter 40.

[0098] During the manufacturing of diffraction plate 1A, the masks used to form each color filter of color filter 40 can be directly used as the first mask 110, the second mask 210, and the third mask 310. Therefore, the misalignment between each diffraction pattern and the corresponding color filter can be suppressed to less than 1 / 10 of the spacing between the color filters, and manufacturing can be simplified.

[0099] Figure 14 In the modified example of the diffracting sheet 1B shown, a diffracting layer 40A is provided instead of diffracting layer 30. Diffracting layer 40A has a first diffracting pattern 41 containing red pigment, a second diffracting pattern 42 containing green pigment, and a third diffracting pattern 43 containing blue pigment. That is, diffracting layer 40A also functions as a color filter.

[0100] Diffracting sheet 1B can be manufactured in the same order as described above simply by mixing the corresponding colorant into the material of the uncured resin layer. Diffracting sheet 1B has the advantage of completely eliminating misalignment between the color filter and the diffraction pattern.

[0101] As described above, the manufacturing method of diffraction sheets 1, 1A, and 1B in this embodiment includes: step A, forming a first uncured resin layer 20 on a transparent substrate 10 with a diagonal of 10 inches or more; step B, bringing a first diffraction pattern 100a formed over a rectangular area with a diagonal of 10 inches or more on one side of a first plate 100 into contact with the first uncured resin layer 20; and step C, placing a first mask 110 having a plurality of first openings 110a formed based on a first arrangement pattern on the first plate 100, and irradiating it with light to cure the portion of the first uncured resin layer 20 that overlaps with the first openings 110a. Step D: Forming a second uncured resin layer 20A on one side of the substrate 10 where the first uncured resin layer 20 is formed; Step E: Contacting the second uncured resin layer 20A with a second diffraction pattern 200a, which is different from the first diffraction pattern 100a, formed over a rectangular area of ​​more than 10 inches diagonally across one surface of the second plate 200; and Step F: Placing a second mask 210 having a plurality of second openings 210a formed based on a second arrangement pattern different from the first arrangement pattern on the second plate 200, and curing the portion of the second uncured resin layer 20A that overlaps with the second openings 210a by irradiating it with light.

[0102] Thus, even large areas with a diagonal diameter of 10 inches or more can achieve high drawing accuracy and form diffraction layers 30 and 40A containing multiple diffraction patterns.

[0103] Furthermore, the diffraction sheet 1A of this embodiment includes: a transparent substrate 10; and a diffraction layer 30, including a first diffraction pattern 21 arranged in a first arrangement pattern on the substrate 10, and a second diffraction pattern 22 arranged in a second arrangement pattern different from the first arrangement pattern on the same side of the substrate 10 as the first diffraction pattern 21. It also includes a color filter 40 disposed between the first diffraction pattern 21 and the second diffraction pattern 22 and the substrate 10 and including a plurality of color filters. When viewed from above, the misalignment between the first diffraction pattern 21 and the second diffraction pattern 22 and the color filters can be less than 1 / 10 of the spacing between the color filters.

[0104] In this configuration, the misalignment between each diffraction pattern 21, 22 and the corresponding color filter can be suppressed. In addition, the mask used to form each color filter of the color filter 40 can be directly used as the mask for fabricating the diffraction patterns 21, 22, thus enabling simple manufacturing.

[0105] Alternatively, the first diffraction pattern 41 and the second diffraction pattern 42 may contain a color material, and the diffraction layer 40A may function as a color filter. This configuration has the advantage of completely preventing misalignment between the color filter and the diffraction pattern.

[0106] Alternatively, diffraction plates 1, 1A, and 1B can also be rectangles with a diagonal shape of 10 inches or more when viewed from above. In this embodiment, as described above, even with a large area of ​​10 inches or more diagonally, high drawing accuracy can be achieved in the diffraction layers 30 and 40A, which include multiple diffraction patterns.

[0107] Reference Figures 15 to 17 The diffraction plate according to the second embodiment of the present invention will be described. In the following description, the same reference numerals as those used for elements already described will be omitted.

[0108] Figure 15 This is a schematic diagram showing the diffraction sheet 2 of this embodiment. The diffraction sheet 2 has a diffraction layer 30A instead of a diffraction layer 30.

[0109] The first diffraction pattern 21 of the three diffraction patterns constituting the diffraction layer 30A is the same as in the first embodiment. The second diffraction pattern 22A is the same as the second diffraction pattern 22, but is formed to be thicker than the second diffraction pattern 22. The third diffraction pattern 23A is the same as the third diffraction pattern 23, and is formed to be thicker than the second diffraction pattern 22A.

[0110] The diffraction plate 2 can be manufactured in a manner largely the same as in the first embodiment. The changes from the first embodiment are described below.

[0111] • In step E, the uncured resin layer 20A is formed to be thicker than the uncured resin layer 20.

[0112] • In step F, the second version 200 stops at a position higher than the first version 100.

[0113] • In step G, the uncured resin layer 20B is formed to be thicker than the uncured resin layer 20A.

[0114] • In step H, the third version 300 stops at a position higher than the second version 200.

[0115] The number of times the diffraction pattern is formed can also be 2 or more, as desired. When the variety of diffraction patterns in the diffraction layer 30A increases, the newly formed uncured resin layer can be formed to be thicker than the previously formed uncured resin layer.

[0116] The diffraction plate 2 and its manufacturing method in this embodiment achieve the same effect as in the first embodiment.

[0117] Furthermore, the later-formed diffraction pattern is thicker, making it difficult for the plate in contact with the uncured resin layer to come into contact with the already formed diffraction pattern. As a result, deformation and damage to the already formed diffraction pattern can be appropriately suppressed.

[0118] In this embodiment, the size of the step difference between diffraction patterns (the height difference between different types of diffraction patterns) h can be appropriately set, for example, it can be set to 100 nm or more and 10 μm or less. Figure 15 In the example, the size h of the step difference between the diffraction patterns is the height difference between the first diffraction pattern 21 and the second diffraction pattern 22A, the height difference between the second diffraction pattern 22A and the third diffraction pattern 23A, and the height difference between the first diffraction pattern 21 and the third diffraction pattern 23A.

[0119] When the step difference becomes too large, the leakage of light, which is incident on adjacent color filters and pixels as stray light, may increase.

[0120] When the average spacing of the diffraction pattern is set as d, the wavelength of light is set as λ, and the diffraction angle is set as θ, the following equation 1 holds true.

[0121] Sin(θ)=λ / d……(1)

[0122] At this point, the width w of the light leakage of diffractor 2 when viewed from above can be calculated according to Equation 2 below. By suppressing the value of w to less than 1 / 10 of the spacing between the color filter and the pixel, the influence of stray light can be reduced to a problem-free level.

[0123] w=h×tan(θ)……(2)

[0124] As another perspective, the size h of the step difference is preferably greater than or equal to the depth of the surface irregularities formed on the upper surface side of the subsequently formed diffraction pattern. Furthermore, the size h of the step difference is preferably at least 1.5 times the depth of the surface irregularities. That is, the size h of the step difference is preferably greater than or equal to the protrusion height of diffraction patterns 100a, 200a, and 300a, and is preferably at least 1.5 times the protrusion height of diffraction patterns 100a, 200a, and 300a. In this way, when the plate comes into contact with a thicker uncured resin layer, it is difficult for the plate to come into contact with the already formed diffraction pattern, thus properly preserving the already formed diffraction pattern.

[0125] As explained above, the method for manufacturing the diffraction sheet 2 in this embodiment is such that, in step D, the second uncured resin layer 20A is formed to be thicker than the first uncured resin layer 20.

[0126] In addition, the thickness difference between the second uncured resin layer 20A and the first uncured resin layer 20 can also be greater than the height of the second diffraction pattern 200a.

[0127] The diffraction sheet 2 of this embodiment includes: a transparent substrate 10; and a diffraction layer 30A, including a first diffraction pattern 21 arranged in a first arrangement pattern on the substrate 10, and a second diffraction pattern 22A arranged in a second arrangement pattern different from the first arrangement pattern on the substrate 10 and on the same side as the first diffraction pattern 21, wherein the second diffraction pattern 22A is thicker than the first diffraction pattern 21.

[0128] According to this configuration, deformation and damage of the diffraction pattern 21 during the manufacturing of the diffraction pattern 22A can be appropriately suppressed.

[0129] Furthermore, the thickness difference between the second diffraction pattern 22A and the first diffraction pattern 21 can also be greater than the depth of the surface unevenness of the second diffraction pattern 22A. According to this configuration, when the plate comes into contact with a thicker uncured resin layer, it is difficult for the plate to come into contact with the already formed diffraction pattern, thus properly maintaining the already formed diffraction pattern.

[0130] Furthermore, the thickness difference between the second diffraction pattern 22A and the first diffraction pattern 21 can be between 100 nm and 10 μm. Based on this configuration, the influence of stray light can be reduced to a negligible level.

[0131] <3D Display Device>

[0132] A three-dimensional display device using the diffraction plate of the present invention will be described. Figure 16 This is a schematic diagram of a three-dimensional display device 51 in which a diffraction sheet 1 is disposed on the incident side of a liquid crystal device LC. That is, the diffraction sheet 1 is disposed between the light source and the liquid crystal device LC. The light emitted from the diffraction layer 30 has an angle that is closer to perpendicular to the diffraction sheet 1 than the light incident on the diffraction sheet 1 from the light source (not shown). Therefore, by properly aligning the diffraction pattern of the diffraction sheet 1 with the pixels of the liquid crystal device LC, light can be guided to the liquid crystal device LC and the color filter mounted on the liquid crystal device LC with high precision.

[0133] Figure 17 This is a schematic diagram of a three-dimensional display device 52 in which a diffraction plate 1 is arranged on the emission side of the liquid crystal device LC. That is, the liquid crystal device LC is positioned between the light source and the diffraction plate 1. The light incident on the liquid crystal device LC becomes highly directional light after passing through the diffraction plate 1, thus enabling high contrast and excellent color rendering.

[0134] In either of the three-dimensional display devices 51 or 52, when the distance between the diffraction plate 1 and the liquid crystal device LC and the color filter is 500 μm or less, the misalignment of light generated between them can be suppressed, which is therefore preferred. The diffraction plate 1 and the liquid crystal device LC are preferably arranged in close contact (i.e., at zero distance). In this case, from the viewpoint of fully utilizing the diffraction effect, a slight air layer or vacuum layer may also exist between the diffraction pattern and the liquid crystal device LC.

[0135] When the diffraction sheet 1 is tightly attached to a liquid crystal device (LC) via an adhesive or bonding agent, it is necessary to make the refractive index of the resin of the diffraction pattern different from the refractive index of the adhesive or bonding agent.

[0136] Furthermore, the diffraction plates in the three-dimensional display devices 51 and 52 are not limited to diffraction plate 1, but may also be diffraction plates 1A, 1B, and 2. Additionally, the three-dimensional display devices 51 and 52 may, instead of a liquid crystal device (LC), include color filters with two or more color filters.

[0137] As described above, the three-dimensional display devices 51 and 52 of this embodiment include: diffraction sheets 1, 1A, 1B, and 2 with a diagonal of 10 inches or more; a transparent substrate 10 and diffraction layers 30, 30A, and 40A including first diffraction patterns 21 and 41 arranged in a first arrangement pattern and second diffraction patterns 22, 22A, and 42 arranged in a second arrangement pattern on the substrate 10; a liquid crystal device LC having multiple pixels and a color filter having two or more color filters; and a light source, wherein the first diffraction patterns 21 and 41 and the second diffraction patterns 22, 22A, and 42 are arranged overlapping with the pixels or color filters in the normal direction of the diffraction sheets 1, 1A, 1B, and 2, and their misalignment is less than 1 / 10 of the spacing between the pixels or color filters.

[0138] Based on this configuration, a good display can be achieved in a large-area 3D display device capable of displaying moving 3D images and colored 3D images.

[0139] Alternatively, diffracting sheets 1, 1A, 1B, and 2 can also be positioned between the light source and the liquid crystal device (LC) or the color filter. Thus, by properly aligning the diffraction patterns of diffracting sheets 1, 1A, 1B, and 2 with the pixels of the liquid crystal device (LC) or the color filter of the color filter, light can be guided to the liquid crystal device (LC) or the color filter with high precision.

[0140] Alternatively, a liquid crystal device (LC) or a color filter can be configured between the light source and diffractors 1, 1A, 1B, and 2. Light incident on the liquid crystal device (LC) becomes highly directional after passing through diffractors 1, 1A, 1B, and 2, thus enabling high contrast and excellent color rendering.

[0141] The various embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the specific configuration is not limited to these embodiments, and includes changes and combinations of configurations that do not depart from the spirit of the present invention. Several modifications are given below, but these are not exhaustive, and other modifications are also possible. These modifications can also allow for appropriate combinations of two or more.

[0142] By appropriately setting the elastic modulus of the diffraction pattern, it is possible to eliminate the need for step differences between diffraction patterns. In this case, it is possible to suppress the damage of the formed diffraction pattern due to the plate and the poor transfer caused by uneven pressure in the newly formed diffraction pattern. From this perspective, the elastic modulus (hardness) of the formed (i.e., cured) diffraction pattern is preferably 0.5 MPa to 100 GPa at room temperature, and more preferably 2500 MPa to 13 GPa.

[0143] In the method for manufacturing diffraction sheets, a parting layer may also be provided on the surface of the diffraction patterns 100a, 200a, and 300a of the various plates 100, 200, and 300 used. In this way, in steps C, F, I, etc., the plates can be easily peeled off after the uncured resin layer has cured, and the diffraction pattern can be appropriately formed.

[0144] Examples of materials that can be used as parting layers include easily lubricated materials such as silicon, fluorine resins, alkyl polymers, and thermosetting resins that become brittle upon heating.

[0145] In the latter case, after the uncured resin layer is cured by light irradiation, the plate is heated to cure the parting layer. Then, when the plate is moved, the brittle parting layer peels off from the plate, leaving residue on the diffraction pattern, thereby facilitating the removal of the plate from the diffraction pattern. The peeled parting layer is then removed from the diffraction pattern by cleaning or the like. After the diffraction sheet is manufactured, a new parting layer is placed on the plate for the next manufacturing process. The thickness of the parting layer peeled off from the plate by heating can be set, for example, to be 10 nm or more and 1 μm or less.

[0146] Alternatively, a transparent material with a refractive index different from that of the resin forming the diffraction pattern can be disposed on the diffraction pattern, thereby making the surface of the diffraction layer flat. In addition, an adhesive resin material (adhesive material) can be used as the transparent material, thereby directly bonding the diffraction layers 30, 30A, 40A to liquid crystal devices (LC), color filters, etc.

[0147] Alternatively, a gas layer or vacuum layer such as air can be disposed on the diffraction layers 30, 30A, and 40A. By placing the diffraction pattern adjacent to the gas layer or vacuum layer such as air, the incident light can be diffracted appropriately.

[0148] The uncured resin layer can also be formed from a thermosetting resin. In this case, each diffraction pattern can be formed by heating only the area corresponding to the arrangement pattern. In this case, the plate can also be opaque, and by forming it from a metal such as nickel, durability can be improved.

[0149] In the diffraction sheets 1, 1A, 1B, and 2 of the present invention described above, multiple diffraction patterns can be arranged without gaps or with gaps (intervals) of a certain width. As long as the width of the gap is less than or equal to the width of the partition wall in the liquid crystal pixel or the black matrix formed in the color filter when viewed from above, the impact on display quality can be minimized. Given the general dimensions of the partition wall and the black matrix, the width of the gap is preferably 1 μm to 100 μm, more preferably 5 μm to 40 μm.

[0150] <Three-Dimensional Spatial Display System>

[0151] In existing technologies, in 3D display devices capable of displaying moving or colored 3D images, when displaying a space with depth that allows for appropriate interpersonal distance (personal space), there is a problem where significant blurring sometimes occurs due to diffraction. The inventors of this application have conducted in-depth research on 3D display devices that, for example, use the aforementioned diffraction sheets 1, 1A, 1B, and 2, can primarily display spaces with a depth of approximately 1.2m to 3.6m (social distancing space) or greater from the display surface as a 3D space with a natural sense of distance and minimal blurring. A detailed description follows.

[0152] Whether in family, intimate relationships, or the business world, understanding each other's feelings during communication is crucial. In the non-verbal aspects, it's important to convey the rhythm of the conversation and the sense of personal space seamlessly, and to glean nonverbal information such as facial expressions and gestures within that sense of distance.

[0153] Various technologies exist to facilitate smooth communication. For example, in the field of communication technology, 5G's low-latency technology reduces communication latency, allowing for a sense of rhythm in online conversations similar to those in real-life conversations. Additionally, three-dimensional measurement technologies such as Time of Flight (TOF) can accurately measure human distance. However, a technology that seamlessly displays a space with depth, providing appropriate interpersonal distance (personal space), does not yet exist.

[0154] In this application, "space with depth" refers to a space larger than the space primarily used for interpersonal communication between people, which allows for a distance of 1.2m to 3.6m. In the following description, this space with depth, allowing for an interpersonal distance of 1.2m to 3.6m, will be referred to as a "social distancing space".

[0155] Various technologies exist for displaying three-dimensional images with depth. These include wearable display devices such as head-mounted displays, polarized glasses, and liquid crystal shutter glasses, as well as non-wearable technologies like parallax barriers and perspective displays that display stereoscopic images by allowing each eye to perceive different parallaxes. These technologies rely solely on parallax to create a sense of depth. Therefore, they require focusing and converging of the gaze to a single point, which can sometimes cause eye strain and dizziness. Consequently, they are sometimes unsuitable as tools for displaying socially distant spaces with depth.

[0156] In contrast, Non-Patent Document 1 discloses a technology that can display three-dimensional images without convergence and focusing.

[0157] Non-Patent Document 1: [online], "Research Trends in Light Field Displays", March 2018, Takafumi Koike, [accessed August 3, 2020], Internet <URL:https: / / home.jeita.or.jp / device / lirec / symposium / fpd / pdf / 2018_2a.pdf>.

[0158] The following display is disclosed in Non-Patent Document 1 (see reference). Figure 36 ): A multi-eye display or microlens array is used to record the light field (the direction information and intensity distribution of light rays incident on the imaging surface of a digital camera) and reproduce (display) the recorded light field. Additionally, a light field display with a static display overlaid with a liquid crystal panel, etc., is proposed (see [reference]). Figure 37 ).

[0159] In addition, according to the stereoscopic image display device described in Patent Document 5, a (multi-eye) technology that makes the number of viewpoints sufficiently large is disclosed.

[0160] Patent Document 5: Japanese Patent Application No. 2007-17634

[0161] According to the technology in Patent Document 5, for human stereoscopic perception, it can satisfy four important factors: binocular parallax, focus accommodation, convergence, and motion parallax. In the display of three-dimensional images by such a multi-eye display and light field display, light is reproduced at a size smaller than the pupil, thereby achieving natural focusing and convergence.

[0162] However, multi-eye displays such as those described in Patent Document 5 reproduce light in a size smaller than the pupil, thereby achieving natural focusing and convergence. Because light is controlled over a tiny area, the blurriness increases with distance from the display surface due to diffraction. Therefore, it can only reproduce objects near the display, making it difficult to reproduce social distance spaces when the display surface is close to the observer. On the other hand, when the display surface is placed away from the observer near a social distance space, the display needs to be larger than the desired display area, resulting in higher costs and a larger installation space.

[0163] As mentioned above, in order to reproduce social distancing spaces, conventional light field displays suffer from significant blurring due to diffraction.

[0164] In view of the above problems, the inventors have studied a light reproduction device, a three-dimensional space display system, a light reproduction method and program, which can display a space (social distance space) with a depth of 1.2m to 3.6m or more from the display surface as a three-dimensional space with a natural sense of distance and less blur.

[0165] Hereinafter, a three-dimensional spatial display system according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. The three-dimensional spatial display system 1S is, for example, mounted using optical devices and circuitry. Furthermore, the present invention is not limited to the embodiments described below, and can be embodied through appropriate combinations and modifications without departing from the spirit of the invention.

[0166] Figure 18 This is a block diagram illustrating the configuration of a three-dimensional spatial display system 1S according to a third embodiment. The three-dimensional spatial display system 1S includes, for example, a communication unit CM, a stereo camera SC, and a three-dimensional display 3D. The communication unit CM communicates with the outside world via a digital communication network NW.

[0167] A stereo camera (SC) is a camera that captures images of the subject, i.e., the object being observed, in three dimensions; for example, it is a stereo camera. The stereo camera (SC) transmits the three-dimensional information of the object being observed to a 3D display (3D) via a communication unit (CM). This three-dimensional information includes at least the incident direction and intensity of light rays from the object onto the shooting surface. It can be information obtained from two or more parallax image sequences, a combination of two-dimensional and distance images, etc., as long as it represents the spatial information including the object being observed.

[0168] Various methods can be considered for acquiring three-dimensional information. For example, when the stereo camera SC is a stereo camera, there are methods that measure depth information (hereinafter also referred to as depth information, depth distance, etc.) by using images captured separately by two cameras, thereby acquiring three-dimensional information. Alternatively, there are methods that analyze the pattern projected onto the object being photographed. Furthermore, there are methods such as Time-of-Flight (TOF) methods that measure the distance to the object being observed by measuring the time of flight of light. Any method can be used to acquire three-dimensional information as long as it can measure at least the required social distance range with the desired resolution. In particular, TOF methods that can measure depth distances of several centimeters to several meters with high precision are preferred.

[0169] The area captured by the stereo camera SC is preferably large enough to allow for the identification of social distancing. For example, a space extending to a depth of 3.6m at an angle of ±30 degrees is preferable as it offers a viewing angle of 60 degrees or more. For instance, based on 35mm film conversion, a viewing angle of 80 degrees or more, equivalent to a 25mm wide-angle lens, allows for capturing a more immersive experience. Furthermore, the minimum angular resolution Δα is preferably 0.033 degrees or less, equivalent to visual acuity of 0.5.

[0170] For example, when the stereo camera SC has a high resolution (1080×1920 pixels), the viewing angle is set to 73 degrees or less to ensure the minimum angular resolution Δα is below 0.033 degrees. Furthermore, when the stereo camera SC has a 4K resolution (2160×3840 pixels), the minimum angular resolution Δα is set to 146 degrees or less. Therefore, when shooting social distancing spaces with a viewing angle of 80 degrees or more, it is preferable to use a stereo camera SC with a resolution of 4K or higher.

[0171] The Communication Department (CM) uses a digital communication network (NW) capable of stably transmitting dynamic images with 3D information to exchange 3D information with external devices. To stably transmit dynamic images including 4K resolution images and depth information for each pixel, a communication speed of 25 Mbps or higher is preferred. When using a mobile communication network, for example, by using a standard of 5G or higher, information exchange with remote locations becomes easier.

[0172] A 3D display is a computer device such as a PC (Personal Computer), server, or cloud server that displays 3D images. A 3D display typically includes, for example, a processing unit 31, a control unit 32, a light source unit 33, a display unit 34, a light control unit 35, and a storage unit 36. Here, the 3D display is an example of a "light reproduction device." The processing unit 31 is an example of a "signal processing unit." The control unit 32 is an example of a "signal processing unit." The display unit 34 is an example of a "stereoscopic image display unit." The light control unit 35 is an example of a "stereoscopic image display unit."

[0173] The arithmetic unit 31 and the control unit 32 are functional units (signal processors) that perform signal processing. For example, they can be implemented by executing a program pre-stored in the storage unit 36 ​​through the CPU (Central Processing Unit) of a 3D display. Alternatively, these signal processing functional units can also be implemented as integrated circuits such as ASICs (Application Specific Integrated Circuits).

[0174] The arithmetic unit 31 calculates the composition (direction and intensity of light) of the light to be reproduced (displayed) based on the three-dimensional information obtained from the stereo camera SC, according to each element unit. The element unit here will be described in detail later.

[0175] The control unit 32 controls the light source unit 33, the display unit 34, and the light control unit 35, reflecting the direction and intensity of the light reproduced according to each element unit. This enables the display of a space with a natural sense of distance and without blurring. Furthermore, when the light source unit 33 and the light control unit 35 in a 3D display are passive and do not require control, it is unnecessary for the control unit 32 to control these functional units (light source unit 33, light control unit 35).

[0176] Furthermore, when displaying images using only 3D information obtained from the outside via the communication unit CM, without using 3D information obtained from the stereo camera SC, the stereo camera SC in the 3D spatial display system 1S can be omitted. On the other hand, when displaying images on the 3D display screen 3D using only 3D information from the stereo camera SC, the communication unit CM can be omitted in the 3D display screen 3D.

[0177] The light source unit 33 has the function of a light source including light-emitting elements such as lasers, LEDs (Light-Emitting Diodes), and EL (Electro-Luminescence), and is a functional unit that serves as the light source for the display unit 34. The light control unit 35 controls the direction and intensity of the light source irradiated by the light source unit 33 according to the control signal from the control unit 32.

[0178] The display unit 34 has a display function using display elements such as LCD (Liquid Crystal Display), OLED (Organic LED), and DMD (Digital Mirror Device). The display unit 34 displays images according to the control of the control unit 32.

[0179] The display unit 34 is generally a display device that displays two-dimensional images, such as LCD, LED, OLED, or DLP (Digital Light Processing). However, it is not limited to this. The display unit 34 can also be a light source unit 33 that scans using a laser light source, LED light source, or other similar source. In the case of self-emissive devices such as LEDs and OLEDs, the display unit 34 simultaneously functions as a light source and a display device. If the display unit 34 can control the direction of light using diffraction patterns such as holograms, then both display and light control functions can be achieved with a single device.

[0180] Additionally, in the following description, display panel 34a (refer to...) Figure 25 (etc.) refers to the surface on which the pattern is displayed by the display device of the display unit 34. When multiple display devices are used to display the image, it refers to the surface closest to the observer.

[0181] The storage unit 36 ​​is composed of a storage medium, such as an HDD (Hard Disk Drive), flash memory, EEPROM (Electrically Erasable Programmable Read Only Memory), RAM (Random Access Read / Write Memory), ROM (Read Only Memory), or any combination of these storage media. The storage unit 36 ​​stores programs for performing various processes on the 3D display screen, as well as temporary data used during these processes. For example, the storage unit 36 ​​stores 3D information acquired by the stereoscopic camera SC. The storage unit 36 ​​stores the calculation results of the arithmetic unit 31. The storage unit 36 ​​stores information representing the direction and intensity of light reproduced under the control of the control unit 32.

[0182] Figure 19 This is a diagram illustrating an example of a three-dimensional spatial display system 1S using the third embodiment. Figure 19 The XY directions represent planar directions, and the Z direction represents the vertical direction. The stereo camera SC is configured to capture images of the physical space JK, which becomes the object of observation. Multiple physical images IM (physical images IM1 to IM7) are arranged within the physical space JK. The 3D display monitor is configured so that the displayed images can be observed by the observer OB.

[0183] A stereo camera SC captures images of the physical space JK. A 3D display shows a reproduced space SK that recreates (displays) the physical space JK captured by the stereo camera SC. Additionally, in... Figure 19In the example, a stereo camera SC is shown overlapping with a 3D display, but they are in different positions in the Z-direction and do not overlap. Additionally, this example shows the stereo camera SC shooting along the X-axis, but it is not limited to this. The position of the stereo camera SC can be any position and direction from which the observer OB wants to observe the physical space JK that is the object of observation. Furthermore, the stereo camera SC is not limited to a single unit; multiple stereo cameras SC can be configured.

[0184] exist Figure 19 In the example, the 3D spatial display system 1S functions as a 3D image display communicator that enables communication between the recording (capturing) and reproduction (display) of 3D information with a time difference. That is, the 3D information of the physical space JK captured by the stereo camera SC is stored in the storage unit 36, and then, at any time desired by the observer OB, the desired 3D image is reproduced in the reproduction space SK. Thus, even if the observer OB is not present during the capture, the physical image IM of the physical space JK at the time of capture can be observed at any time after the capture.

[0185] Furthermore, while the examples of recording and reproducing with a time difference have been shown above, this is not a limitation. For instance, a stereoscopic camera SC and a 3D display can be positioned in separate locations such as a hallway and a living room, functioning as a 3D image communicator for communication in such isolated locations where direct visual observation is not possible. Thus, the observer OB can experience (observe) the physical space JK from a distance without moving there.

[0186] Here, we will describe in detail the social distance space that is the subject of this application. Social distance space is not the space displayed by a conventional three-dimensional display (stereoscopic image display device) where objects (subjects) exist near the display. Social distance space is the space within the space displayed by the display, where the subject exists at a position separated along the depth direction. Social distance space can be, for example, the space inside a room, the space in a park, etc., a space where an observer (subject) exists within that space. It can also be the space displayed when the display is used as a window to observe the space outside (such as the space inside a room) from that window.

[0187] American cultural anthropologist Edward Hall categorized interpersonal distance (personal space) between people into the following four distance zones.

[0188] 1) Close contact distance

[0189] 2) Individual distance

[0190] 3) Social distancing

[0191] 4) Public Distance

[0192] 1) such as Figure 19 As shown, close proximity ID refers to a distance of 0 to 0.45 meters from another person, such as a distance close enough to perceive their body temperature or scent. Close proximity is the distance between people in a very intimate relationship, primarily involving skin contact such as holding hands and communication based on scent.

[0193] 2) Individual distance (PD) refers to a distance of 0.45 to 1.2 meters between oneself and another person. It is the distance one maintains in order to maintain independence from others. It is the distance at which one or the other person can reach out and touch, and it is the interpersonal distance when communicating with close people such as friends.

[0194] 3) Social distance (SD) refers to a distance of 1.2 to 3.6 meters between people, which is a distance that makes it difficult to touch the other person. It is the interpersonal distance suitable for formal occasions such as conversations between colleagues in the workplace.

[0195] 4) Public distance refers to a distance of 3.6m or more between two people that is not suitable for communication, such as interpersonal distance in the context of giving speeches or lectures.

[0196] Figure 20 This is a block diagram illustrating the configuration of the three-dimensional spatial display system 100S according to the fourth embodiment. In the three-dimensional spatial display system 100S of this embodiment, multiple... Figure 18 The three-dimensional spatial display systems 1S (1S-2, 1S-2, etc.) shown are interconnected via a digital communication network NW. This constitutes multiple three-dimensional image display exchangers that can remotely communicate with each other naturally. Furthermore, the three-dimensional information acquired by the stereo cameras SC (SC-1, SC-2, etc.) is compressed and / or converted as needed through signal processing by the arithmetic unit 31, etc., and then transmitted to the communication destination via the communication unit CM (CM-1, CM-2, etc.).

[0197] In addition, there are no particular restrictions on the communication means of the Communication Department CM, but since it is necessary to send and receive three-dimensional information, it is preferable to have a communication means that can transmit large amounts of information at high speed, such as the 5G communication network listed above.

[0198] Figure 21 This is a diagram illustrating an example of a three-dimensional spatial display system 100S using the fourth embodiment. Figure 21 The XY directions represent the planar direction, and the Z direction represents the vertical direction. The position, orientation, and number of stereo cameras (SC) are determined by... Figure 19The same applies to 3D display monitors. In the example shown in the figure, the 3D spatial display system 100S functions as a 3D image display exchanger that enables natural communication between two remote locations connected via a digital communication network NW.

[0199] That is, the stereo camera SC-1 captures three-dimensional information of people existing in the physical space JK-1, and transmits it to the three-dimensional display screen 3D-2 via the digital communication network NW. As a result, the three-dimensional display screen 3D-2 displays a reproduced space SK-1, which is a reproduction of the space (physical space JK-1) captured by the stereo camera SC-1.

[0200] On the other hand, the stereo camera SC-2 captures three-dimensional information of a person (in this example, one person) existing in the physical space JK-2, and this information is transmitted to the three-dimensional display screen 3D-1 via the digital communication network NW. Thus, the three-dimensional display screen 3D-1 displays a reproduced space SK-2, which is a reconstruction of the space (physical space JK-2) captured by the stereo camera SC-2.

[0201] Here, use Figure 22 The elements and units of this embodiment will be described. Figure 22 It is a characteristic graph that shows the relationship between the distance from the 3D display to the object being observed and the magnitude of the blur produced when the object is reproduced. Figure 22 The horizontal axis represents the distance from the monitor. Figure 22 The vertical axis represents the size of the blur.

[0202] Generally speaking, in monitors capable of focusing, such as Figure 30 As shown, when an observer observes the space in front of and behind the display through the display surface 34a, and when a ray of light extending from the point object to be reproduced, i.e. the point of reproduction, is reproduced at a size smaller than the observer's pupil, the observer can observe it as if a point light source exists in the space.

[0203] However, strictly speaking, the light reproduced by the display is as follows: Figure 31 As shown, light becomes diffused due to various reasons, which is an important factor in the blurring of the reproduced image. In particular, when the display element unit that determines the direction of the light is small, the light is diffused around the outside of the opening due to the diffraction effect of the element unit as an opening, resulting in blurring.

[0204] The diffraction extension caused by the opening can be approximated as Fraunhofer diffraction at a position far from the display surface 34a. In the case of a circular opening, its extension angle can be determined based on the size of the Airy disk (the brighter region produced at the center of the diffraction pattern). That is, for the distance between the smallest dark ring formed in the far field of view away from the circular opening and the optical axis, when expressed using the extension angle θ of the light rays parallel to the optical axis and passing through the end face of the circular opening, it can be represented as follows (see...). Figure 32 Here, λ in (Equation 3) is the wavelength of light, and d is the diameter of the circular opening.

[0205] θ=1.22×λ / d ……(Equation 3)

[0206] The opening described above becomes a unit of area on the display that defines the direction of light. This unit is called a "feature unit". Hereinafter, the feature unit will be described using the reference numeral C. A collection of multiple feature units C is called a feature unit set. Feature unit C is, for example, a light field display using a microlens array (…). Figure 36 In a light field display (e.g., a lens corresponds to element unit C), a lens is equivalent to element unit C. Additionally, in a static display type light field display with superimposed liquid crystal panels, etc.,... Figure 37 In the case of ), the pixels of the display used become the element unit C.

[0207] In a light field display, the direction of light is controlled according to each element unit C. Therefore, in order to have a focusing function, the element unit C needs to be sufficiently smaller than the observer's pupil. Generally, the size of a human pupil is around 2 to 8 mm. Therefore, when the size of the element unit C is set to 0.3 mm and the wavelength of light is set to 500 nm, the spread angle of the light is represented by (Equation 3) as follows.

[0208] θ = 1.22 × 500 × 10 -6 / 0.3

[0209] ≈2.03×10 -3 (rad)

[0210] ≈0.12 (degree)

[0211] That is, in Figure 32 The blur produced by a ray of light passing through a 0.3mm element C located at a distance L = 3.6m from a surface with a circular opening is 3600 × tan(0.12°) × 2 ≈ 15 (mm), meaning it extends to a length of approximately 15mm. For example, when a 15mm blur is produced on the face of a person at a distance of 3.6m, although the person can be identified, their expression is difficult to read.

[0212] Generally, a person with 1.0 visual acuity has an angular resolution of 1 / 60 degree with the naked eye. The element unit C, whose size d is equivalent to the diffraction-induced expansion angle θ, can be represented as follows by (Equation 3) when the wavelength is set to 500 nm.

[0213] d = 1.22 × 500 × 10 -6 / tan(1 / 60°)×2

[0214] =4.2mm

[0215] Similarly, the element cell C, which has a resolution equivalent to 1 / 60 / 0.7 degrees of visual acuity (the condition for a driver's license), and produces blur, has a size of 2.9 mm. The minimum visual acuity without glasses is 0.3, and the size of the element cell C producing blur, calculated using the same method under this condition, is 1.2 mm. Under the condition of 0.2 visual acuity, the size of the element cell C producing blur is 0.8 mm. From this, it can be said that in order to suppress blur that is permissible during observation, a size d of element cell C of at least 0.8 mm is required.

[0216] Here, in Figure 22 In this context, the size d of feature cell C is used as a parameter to represent the relationship between the distance L from the display and the magnitude of blur caused by diffraction. The size d of feature cell C is equivalent to... Figure 32 The d in the figure refers to the dimension d of the element unit C calculated above, which is equivalent to a dimension calculated as d = 4.2 mm, 2.9 mm, 1.2 mm, or 0.8 mm depending on the conditions.

[0217] like Figure 22 As shown, if the distance (L) from the display is the same, the larger the size (d) of the element unit C, the smaller the blur. This is reflected in Equation 3 as the larger d is, the smaller the spread angle θ is.

[0218] Here, use Figure 23 The interval (spacing p) of the configuration element unit C is explained. Figure 23 It is a characteristic graph that shows the relationship between the distance from the 3D display to the object being observed (object distance) and the resolution (circle of confusion diameter) on the retina of the observer viewing the reproduced object. Figure 23 The horizontal axis represents the distance from the monitor. Figure 23 The vertical axis represents the diameter of the dispersion circle.

[0219] Generally, the size of a human pupil is between 2 and 8 mm, allowing multiple rays of light to pass through it for focusing. To achieve this focusing, the element units C need to be spaced (p) apart, such that light rays from at least two element units C enter the pupil. For a more natural focusing, the number of rays entering the pupil (the number of element units C) is preferably higher. That is, to increase the number of element units C, it is preferable to reduce the spacing (p) between the element units C.

[0220] like Figure 23 As shown, if the distance (L) from the observer to the object is the same, the smaller the spacing (p) of the element cells C, the smaller the diameter of the circle of confusion. The spacing between photoreceptor cells on the human retina is approximately 10 μm (0.01 mm). Therefore, to achieve good resolution (a smaller diameter of the circle of confusion), for objects farther than 1.2 m, a spacing p of element cells C of approximately 0.4 mm or less is required.

[0221] Furthermore, it is known that if the application allows for a resolution similar to that of a 24-inch XGA (Extended Graphics Array: a standard published by IBM in 1990) display at a distance of 0.5m (with a circle of confusion diameter of 30μm (0.03mm) on the retina), then for objects farther than 1.2m, the spacing p of the element units C can be configured to be less than 1.2mm.

[0222] In summary, if communication is conducted at a social distance SD (a distance of approximately 1.2m to 3.6m from the display), then as long as the size d of the element unit C is greater than 0.8mm and the spacing p of the element units C is less than 1.2mm, practically unimpeded communication can be achieved.

[0223] in addition, Figure 23 The horizontal axis represents the distance from the observer to the object, but the distance from which the observer observes the display surface 34a of the device is unknown during the design process. Therefore, during the design, it is assumed that the observer is closest to the display surface 34a, and the distance from the observer to the object is used as the distance from the display surface 34a to the object in the calculation.

[0224] Figure 24 This is a schematic diagram of the case where the spacing p of the element C is greater than the size d of the element C (p ≥ d). This is an example where the size d of the element C is 0.8 mm or more and the spacing p of the element C is 1.2 mm or less. In this case, since p ≥ d, the element Cs do not overlap. Therefore, the diffraction grating pattern (diffraction pattern) also does not overlap and is independent.

[0225] Figure 25 This is a conceptual diagram illustrating the case where a point object is reproduced as object point A' using the display of the present invention. Each element unit C reproduces the direction of light (virtual light L') emitted from object point A' in the display surface 34a. When viewed from various directions above the drawing (i.e., when viewing the display surface 34a from various directions from the observer OB side), the observer OB can observe it as if object point A' exists in all directions.

[0226] In this embodiment, as in Figure 23 As explained earlier, this assumes that the spacing p of the element units C is sufficiently small relative to the size of the pupil. Additionally, as in... Figure 22 As explained earlier, the size d of the element unit C is assumed to be a size with less blurring caused by diffraction. Therefore, the conditions required for stereoscopic display, such as convergence, focusing, and binocular parallax, are reproduced to the observer OB without contradiction. As a result, the observer OB will not experience eye fatigue. That is, even in a space far from the display surface 34a, a natural and seamless space can be reproduced.

[0227] On the other hand, such as Figure 25 As shown, the light rays emitted from each element unit C (reproduced light L) have the size (d) of element unit C plus the width of the spread (Δα) caused by diffraction. Therefore, there is no problem when observing a space far from the display surface 34a, but when observing an object close to the display surface 34a, the resolution of the object decreases.

[0228] Several methods can be considered as countermeasures. For example, such as Figure 26 As shown, it is possible to consider making the distribution of brightness of the light reproduced from element C a characteristic distribution. Figure 26 This is a diagram showing an example of the distribution of brightness of the light rays (reproduced light L) reproduced from element cell C. Figure 26 The upper part is a characteristic diagram showing the relationship between the position within element cell C and the brightness of the reproduced light L. Figure 26 The lower part is a schematic diagram of the image showing the distribution of the brightness of the reproduced light L emitted from element C.

[0229] like Figure 26 As shown, the brightness of the light reproduced from element cell C is distributed such that it is brighter at the center and darkens towards the periphery. This improves the resolution of the reproduced object. To produce such a brightness distribution, a variation in diffraction efficiency is created within element cell C such that the transmittance of the interference fringe pattern recorded in element cell C decreases from the center towards the periphery.

[0230] In addition, as a method to prevent resolution degradation, such as Figure 27 As shown, it is possible to consider adjusting the size of the object point A'' generated by the rays of the reproduced light L reproduced from each element unit C. That is, as element unit C, an element unit C is formed on the display surface 34a that records the interference fringes of the spherical wave generated by the virtual light L'' diffused from the object point A'', i.e., the wavefront from the object point, and the reference light. Thus, as Figure 27 As shown, the size of the object point A'' generated by the light reproduced from each element C can be reduced to the diffraction limit of the size d of the element C.

[0231] One method to achieve this is to use a Computer-Generated Hologram (CGH) calculated for each element cell C. In this method, the wavefront and the hologram of the reference light are calculated when the light (virtual light L'') from the object reaches the position of element cell C. In this method, the calculation is performed for each element cell C. Therefore, a high-speed computation, which requires less computation than a typical CGH calculation and can be performed in parallel, is possible.

[0232] In this case, even a single element unit C is sufficient to achieve focusing. Therefore, even if the spacing p of the element units C is 1.2 mm or more, a natural stereoscopic display can be achieved. However, in order to ensure that the image changes smoothly as the viewpoint of the observer OB moves, the spacing p of the element units C is preferably less than the size of the pupil. Therefore, the spacing p of the element units C is at least 7 mm or less, and preferably less than 2 mm. That is, when the element unit C is used as a hologram that records spherical waves from an object, by setting the size d of the element unit C to 1.2 mm or more (equivalent to visual acuity of 0.5) and the spacing p of the element units C to 2 mm or less, a higher resolution stereoscopic image can be observed.

[0233] use Figure 28 For passing Figure 27 The method reproduces the morphology of multiple objects and is explained. In each element unit C of the display surface 34a, interference fringes of spherical waves diffused from points on the surface of the object and reference light are recorded. From object B', which is located relatively close to the display surface 34a, spherical waves diffused from closer light points are reproduced. On the other hand, from object C', which is located relatively far from the display surface 34a, spherical waves diffused from farther light points are reproduced. Thus, the wavefronts are recorded differently depending on the distance from the display surface 34a to the object.

[0234] In this embodiment, the interference fringes of spherical waves spreading from various points on the surface of an object and reference light are digitized using a stereo camera (SC). This is similar to conventional digital holograms, but the characteristic of this embodiment is that the object is sampled. That is, as... Figure 29 As shown, the sampling points for the object are set as points that have been decomposed from the positions of each element unit by an angle of Δα.

[0235] Therefore, in conventional digital holograms, wavefront calculations require sampling intervals at the μm level, while in the method of this embodiment, sampling intervals of several millimeters to several centimeters are sufficient. This significantly reduces the enormous computational load required in conventional methods.

[0236] Furthermore, in the method of this embodiment, the sampling interval (sampling distance) expands the further away from the display surface 34a. Therefore, the method of this embodiment is suitable for reproducing a large space far from the display surface 34a.

[0237] In holographic stereoscopic imaging, a stereoscopic image is created by reproducing the direction of light. Therefore, data for displaying three-dimensional images can be generated based on images of an object taken from multiple directions. Thus, using CG (computer graphics) methods studied through various approaches, not only the shape but also the texture of objects, such as glossy or transparent objects, can be reproduced. Furthermore, by photographing actual objects, stereoscopic images of real objects can be reproduced.

[0238] For example, using Figure 29 This section explains a method for calculating holographic patterns using ray tracing, a CG method. First, the center of each element unit C is taken as the starting point for the rays emitted by the ray tracing method. Next, ray tracing is performed with the center of each element unit C as the starting point to find the intersection points of the rays with the object that becomes the subject. Thus, a pattern of element units C with parallax in all directions (up, down, left, and right) can be created by having a set of point light sources from different viewpoints for each element unit C. Furthermore, the object (subject) here can be a 3D object created based on 3D information obtained from information captured by a stereo camera SC, or a hypothetical (virtual) object created using CAD (computer-aided design), etc. Additionally, when only the direction of the rays is considered in this calculation, the pattern becomes... Figure 25 The reproduction of the light rays shown. On the other hand, when both the direction of the light ray and its distance to the object point are considered in this calculation, it becomes... Figure 27 , Figure 28 The reproduction of light as shown.

[0239] Here, use Figure 33 The flowchart describes the process of processing performed by the 3D display in the embodiment. Figure 33 The flowchart illustrates the calculation process for the hologram pattern, taking into account the direction of the light rays and their distance from the object point.

[0240] First, the 3D display acquires the 3D information of the object to be displayed on the display (step S10). Next, the 3D display determines the position of the center of the element unit C to be calculated (step S11), and calculates the intersection points of each line emanating from the center of element unit C with an angle difference of Δα with the object (step S12). Then, the 3D display uses each intersection point with the object as an object point and calculates the sum of the complex amplitudes of the spherical waves spreading from each object point at the element unit position (step S13). Furthermore, the complex amplitude calculated here can be within the range of the size of element unit C.

[0241] The 3D display performs the above processes (steps S11 to S13) (steps S14 and S17) on all element units C.

[0242] Then, the 3D display calculates the sum of the complex amplitudes of all element units C, thereby calculating the complex amplitude on the display surface 34a (step S15). Next, the 3D display calculates the pattern of interference fringes between the wavefront of the reference light and the complex amplitude on the display surface 34a (step S16). Thus, the 3D display can calculate the pattern of the hologram displayed on the display.

[0243] In the process shown in the flowchart above, instead of calculating the sum of the interference patterns of each element unit C, the sum of the complex amplitudes is calculated (step S15). Then, the interference patterns of these sums with the reference light are calculated (step S16). Thus, the 3D display can record and reproduce the 3D image of an object as information including both the direction of the light rays and the distance to the object point.

[0244] Furthermore, in the process shown in the flowchart above, after calculating the sum of the complex amplitudes of element unit C, the interference pattern between it and the reference light is calculated, but it is not limited to this. The 3D display can also calculate the sum of each interference pattern after calculating the interference pattern with the reference light for each element unit C. In this case, the 3D display can perform the calculation for each element unit C. Therefore, parallel computing becomes easier, and the computation time can be reduced.

[0245] Furthermore, the recorded stereoscopic image (three-dimensional information of the object) can be a stereoscopic image that only considers the parallax in the horizontal direction, but to make the focusing effect more effective, it is preferable to have a stereoscopic image that has parallax in both the horizontal and vertical directions. In the above embodiment, a circular unit is used as an example and described as element unit C, but it is not limited to this. The shape of element unit C can also be a polygon such as a triangle, quadrilateral, pentagon, or hexagon, or it can be a star, ellipse, rectangle, or other shapes.

[0246] Furthermore, as the light source for reproducing the holographic stereoscopic image, a monochromatic light source such as a laser or LED, or a light source composed of a combination of a conventional light source and a filter, is preferred. This is to suppress blurring caused by differences in diffraction angles due to wavelength.

[0247] Furthermore, when using a laser source as the light source, it is preferable to focus on reducing inertia. This is to reduce noise caused by speckle. To reduce the inertia of the laser source, methods such as fiber transmission, vibration of the source, variation of the optical path length, insertion of movable diffusion elements into the optical path, and combination of multiple source sources can be considered.

[0248] In the above, the social distance SD refers to a distance of approximately 1.2m to 3.6m, but it is not necessary for all objects reproduced in space to exist within this distance range. The object that becomes the primary object of observation only needs to exist at least within the social distance SD range. Furthermore, the object being reproduced is not limited to people; it can also be animals, robots, etc. Additionally, the object being reproduced can be a two-dimensional image reproduced in space. Moreover, it can also reproduce buildings that suggest the presence of a communication partner, such as tables, chairs, or platforms placed in space. Furthermore, the reproduced object does not necessarily involve direct communication. For example, it could be a mountain or other terrain that exists within the social distance SD range when remotely operating heavy machinery. The same applies to remote surgery, the operation of robotic arms in space, and the operation of unmanned reconnaissance aircraft.

[0249] If used Figure 22 , Figure 23 As explained, even when the depth of a space exceeds 3.6m, this invention can reproduce large spaces with minimal blurring. For example, this invention can be used to represent large spaces such as landscapes, spaces containing buildings, large plants and animals, and spaces exceeding the social distancing limit (SD).

[0250] Furthermore, when observing the display via an optical system such as an eyepiece lens, the dimensions d of the element unit C and the spacing p of the element units can be corrected based on the magnification of the optical system. For example, in a social distance SD of approximately 1.2m to 3.6m from the display, without an eyepiece lens, the dimensions d of the element unit C can be set to 1.0mm and the spacing p of the element unit C to 1.2mm. In this case, when applying this embodiment to a head-mounted display, etc., with the magnification of the eyepiece lens installed in the head-mounted display, etc., being 2x, the 3D display corrects the dimensions d of the element unit C to 1.0 / 2 = 0.5mm and the spacing p of the element unit C to 1.2 / 2 = 0.6mm. Conversely, when using a reduced optical system and setting the magnification of the optical system to 0.5, the 3D display corrects the dimensions d of the element unit C to 1.0 / 0.5 = 2.0mm and the spacing p of the element unit C to 1.2 / 0.5 = 2.4mm.

[0251] That is, the corrected dimensions d# and p# are expressed by the following formula. In the following formula, d represents the dimension before correction, p represents the spacing before correction, and BR represents the magnification of the optical system such as the eyepiece lens.

[0252] d#=d / BR

[0253] p#=p / BR

[0254] Furthermore, when directly observing the display surface 34a without using an eyepiece or similar lens, it is preferable to be able to observe with both eyes simultaneously in order to achieve a converging effect. The average interocular distance is approximately 60 mm, therefore the size of the display surface 34a is preferably at least 60 mm or more in the long axis direction.

[0255] (Modifications of the implementation method)

[0256] Here, a variation of the implementation method will be described. In this variation, the difference from the above-described implementation method is that a virtual object (hereinafter referred to as a virtual object) is reproduced in the reproduction space. The virtual object is, for example, a virtual character.

[0257] Figure 34 This is a block diagram illustrating the configuration of a three-dimensional spatial display system 1SA, a modified example of the embodiment. The three-dimensional spatial display system 1SA includes, for example, a communication unit CM and a three-dimensional display screen 3D. That is, in this modified example, the stereoscopic camera SC can be omitted.

[0258] The Communication Unit (CM) acquires 3D information about virtual objects from external sources. Virtual objects include not only the objects being observed, but also 3D information about the space in which the object is reproduced, such as the background. The 3D display uses the 3D information about the virtual objects acquired via the CM to reproduce, for example, the space in which the virtual object exists at social distancing (SD).

[0259] Alternatively, the 3D display can also have a function unit for creating 3D information of virtual objects. Alternatively, the 3D display in this modified example can also use 3D information of virtual objects pre-stored in the storage unit 36. In this case, the communication unit CM can be omitted in the 3D spatial display system 1S.

[0260] Figure 35 This is a diagram illustrating an example of a three-dimensional spatial display system 1SA that utilizes a modified embodiment of the implementation method. Figure 35 In, for example, it can be passed through Figure 34 The three-dimensional images of the generated virtual objects shown are displayed on the monitor as reproduction images SIM (in this example, reproduction images SIM1 to SIM7) existing in a reproduction space SK. Thus, by using the 3D display monitor of this variant example, more natural communication can be conducted in a social distance space with depth, where social distance SD can be obtained between non-physical objects such as characters and roles created in the virtual space and avatars of communication objects sent from other systems.

[0261] The means of communication in this variation is not limited to a specific means. For example, a 3D spatial display system 1SA can also be used as a means of communication with a character. Here, the character is a virtual character displayed as a virtual object.

[0262] In this case, the 3D spatial display system 1S includes, for example, a live camera and a processor. The processor performs signal processing to display a 3D spatial image in which a character has taken a predetermined response. The live camera captures a video of the user. The processor recognizes the user's gestures from the image captured by the live camera, determines the response the character should take based on the gestures, and displays an image of the character who has taken the determined response. Thus, it is possible to communicate with the character using gestures.

[0263] Alternatively, the 3D spatial display system 1SA includes a microphone, a speaker, and a processor. The processor performs signal processing to display a 3D spatial image that elicits a predetermined response from a character. The user's voice is input into the microphone. The processor determines the appropriate response based on the user's voice input and outputs the determined response from the speaker. Furthermore, the processor determines the character's response based on the user's voice and displays an image of the character who has taken the determined response. Thus, communication with the character via voice is possible.

[0264] Furthermore, in this variation, the virtual object may not be CG (Computer Graphics), but rather a real-life animated image captured in advance using a stereoscopic camera or the like. In such a case, the animated image reproduced in response to user input such as gestures or voice can be switched, thereby enabling interaction (communication) with the virtual object.

[0265] Furthermore, when the virtual object reproduced (displayed) by the three-dimensional spatial display system 1SA is a static object, the display unit 34, which is a three-dimensional display display 3D, can also display unchanging (static) images such as printed materials.

[0266] Furthermore, the image displayed by the display unit 34 of the 3D display can also be an image of a holographic pattern drawn using a tiny drawing device such as an electronic line drawing device, and then a copy of the drawn holographic pattern. In this way, by using a fixed holographic pattern (still image) as the displayed image, a large space can be reproduced at low cost. In this case, the display unit 34 controls the direction of light through the holographic pattern. The display unit 34 displays the holographic pattern as at least one of a virtual image or a real image through the light emitted from each element unit C. Therefore, the display function and the light control function can be implemented by a single device. In this case, the virtual character displayed as a virtual object cannot react, but it is possible to communicate with the simulated virtual object through voice as described above. Alternatively, the light control unit 35 can display a fixed holographic pattern or other still image along with or in place of the display unit 34. The display unit 34 is an example of a "stereoscopic display unit." The light control unit 35 is an example of a "stereoscopic display unit." Furthermore, an image depicting a holographic pattern is an example of a "stereoscopic image." An image that replicates the depicted holographic pattern is also an example of a "stereoscopic image."

[0267] As explained above, the 3D display (light reproduction device) of the embodiment reproduces the light rays virtually emitted from the stereoscopic image when the stereoscopic image is reproduced in the reproduction space SK.

[0268] The 3D display of the embodiment includes a display unit 34 and / or a light control unit 35. The display unit 34 and / or the light control unit 35 is an example of a "stereoscopic image display unit." The display unit 34 and / or the light control unit 35 displays a stereoscopic image, at least as either a virtual image or a real image, by using light emitted from each element unit C included in a set of element units C arranged in two dimensions corresponding to the reproduced image. The display unit 34 and / or the light control unit 35 displays the stereoscopic image in a region within the reproduction space SK where the distance in the depth direction corresponds to the social distance SD. Furthermore, in the 3D display, the element unit size d and the element unit spacing p are values ​​determined based on the degree to which the observer OB observes the stereoscopic image reproduced in the reproduction space SK. The stereoscopic image is reproduced in a region within the reproduction space SK where the distance in the depth direction corresponds to the social distance SD.

[0269] Therefore, the 3D display of this embodiment can determine the size d of the element unit C and the spacing p of the element units C so that the stereoscopic image at the social distance SD in the reproduction space SK can be well observed by the observer OB. Thus, the social distance space can be reproduced as a 3D space with a natural sense of distance and less blur.

[0270] Furthermore, the 3D display in this embodiment includes a calculation unit 31 and / or a control unit 32. The calculation unit 31 and / or the control unit 32 is an example of a "signal processing unit". The calculation unit 31 and / or the control unit 32 calculates the direction of the light rays to be reproduced for each element (element unit C) of the element unit set. The element units C are arranged in two dimensions corresponding to the reproduced screen. Each element, obtained by dividing the set of multiple light rays emitted from the surface of the stereoscopic image according to the position of each light ray reaching the reproduced screen, is associated with the element unit C. As a result, the same effect as described above can be achieved.

[0271] Furthermore, in the 3D display of the embodiment, the size d of the element unit C is determined according to the magnitude of the blur generated in the reproduced stereoscopic image. Therefore, by determining the size d of the element unit C in a manner that allows for the suppression of an acceptable level of blur, it is possible to reproduce a stereoscopic image with less blur.

[0272] Furthermore, the spacing p of the element units C is determined based on the resolution on the retina of the observer OB observing the reproduced stereoscopic image. Thus, by determining the spacing p of the element units C in a way that allows for focusing, a stereoscopic image that can be focused on by the observer OB can be reproduced.

[0273] Furthermore, the size of element cell C can be determined by d in a manner smaller than the spacing p of element cells C. Additionally, the size d of element cell C can be 0.8 mm or more, and the spacing p of element cells C can be 1.2 mm or less. Therefore, practically barrier-free communication is possible in displays that show social distancing (SD).

[0274] Alternatively, element C can also be a hologram that records the wavefront from the stereo image.

[0275] All or part of the 3D spatial display system 1S (1SA, 100S) and the 3D display screen described in the above embodiments can also be implemented by a computer. In this case, the program for implementing the function can be recorded on a computer-readable recording medium, and the computer system can read and execute the program recorded on the recording medium. Furthermore, "computer system" here includes hardware such as an operating system and peripheral devices. "Computer-readable recording medium" refers to removable media such as floppy disks, optical disks, ROMs, and CD-ROMs, and storage devices such as hard disks built into the computer system. Moreover, "computer-readable recording medium" can also include: a medium that dynamically maintains the program for a short period of time, such as a communication line in the case of transmitting the program via a network such as the Internet or a communication line such as a telephone line; or a medium that maintains the program for a certain date and time, such as volatile memory inside a computer system that serves as a server or client in this case. Furthermore, the program described above can be a program for implementing a part of the above functions, or a program that can implement the above functions by combining with a program already recorded in the computer system, or a program implemented using a programmable logic device such as an FPGA.

[0276] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the specific configuration is not limited to these embodiments, and also includes designs that do not depart from the scope of the invention.

[0277] Explanation of reference numerals in the attached figures

[0278] 1, 1A, 1B, 2 diffraction plates

[0279] 10 substrates

[0280] 20 Uncured resin layers (first uncured resin layer)

[0281] 20A Uncured Resin Layer (Second Uncured Resin Layer)

[0282] 20B Uncured Resin Layer (Third Uncured Resin Layer)

[0283] 21, 41 First Diffraction Pattern

[0284] 22, 22A, 42 Second Diffraction Pattern

[0285] 30, 30A, 40A diffraction layers

[0286] 40 color filter

[0287] 51, 52 Three-dimensional display devices

[0288] 100 First Edition

[0289] 100a First Diffraction Pattern

[0290] 110 First Mask

[0291] 110a opening (first opening)

[0292] 200 Second Edition

[0293] 200a Second Diffraction Pattern

[0294] 210 Second Mask

[0295] 210a opening (second opening)

[0296] LC liquid crystal device

[0297] 1S, 1SA, 100S... 3D Spatial Display System

[0298] CM...Ministry of Communications

[0299] SC... Stereo Camera

[0300] 3D... Three-dimensional display (light reproduction device)

[0301] 31...Arithmetic Unit (Signal Processing Unit)

[0302] 32……Control Department (Signal Processing Department)

[0303] 33……Light Source Department

[0304] 34……Display Unit (Stereoscopic Display Unit)

[0305] 35……Light control unit (stereoscopic image display unit)

[0306] 36……Storage Department

[0307] C……Element Unit

[0308] OB...Observer

[0309] SD... Social distancing

[0310] d…… Dimensions of the element unit

[0311] p... Spacing of element units

Claims

1. A method for manufacturing a diffraction plate, comprising: Step A: Forming a first uncured resin layer on a transparent substrate with a diagonal width of 10 inches or more; Step B involves bringing a first diffraction pattern, formed over a rectangular area extending more than 10 inches diagonally across one surface of the first print, into contact with the aforementioned first uncured resin layer. Step C involves placing a first mask having a plurality of first openings formed based on a first arrangement pattern on the first plate and irradiating it with light to cure the portion of the first uncured resin layer that overlaps with the first openings. Step D: Forming a second uncured resin layer on the side of the substrate on which the first uncured resin layer is formed; Step E involves bringing a second diffraction pattern, different from the first diffraction pattern, formed over a rectangular area extending more than 10 inches diagonally across one surface of the second plate into contact with the second uncured resin layer; and... Step F involves placing a second mask with multiple second openings formed based on a second arrangement pattern different from the first arrangement pattern on the second plate, and irradiating it with light to cure the portions of the second uncured resin layer that overlap with the second openings.

2. The method for manufacturing a diffraction plate as described in claim 1, wherein, The hardness of the first uncured resin layer after curing is 0.5 MPa to 100 GPa at room temperature.

3. The method for manufacturing a diffraction plate as described in claim 1, wherein, In step D above, the second uncured resin layer is formed to be thicker than the first uncured resin layer.

4. The method for manufacturing a diffraction plate as described in claim 3, wherein, The thickness difference between the second uncured resin layer and the first uncured resin layer is greater than or equal to the height of the second diffraction pattern.

5. The method for manufacturing a diffraction plate as described in claim 1, wherein, At least one of the aforementioned first version and the aforementioned second version has a fractal layer on one of the aforementioned surfaces.

6. The method for manufacturing a diffraction plate as described in claim 5, wherein, The aforementioned parting layer is mainly composed of thermosetting resin, silicone, fluorine resin, or any one of alkyl-containing polymers.

Images