Display device, display method, and program

Abstract

To improve how a three-dimensional image displayed by a volume display looks like.SOLUTION: A display device 10 includes: a display body 12 on which a plurality of screens 22 are laminated, the screen being capable of switching a light transmissive state and a light diffusing state; an irradiation unit 14 for irradiating the display body 12 with image display light 24; a sensor 16 for detecting the position of an observer 26 with respect to the display body 12; and a control unit 18 for simultaneously controlling switch between the transmissive state and the diffusion state of each screen 22 and switch of the display content of the image display light 24 emitted from the irradiation unit 14 according to the position of the observer 26 detected by the sensor 16, in synchronization with each other.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a display device, a display method, and a program. [Background technology]

[0002] A volumetric display, which displays a three-dimensional image in space, is known. For example, a volumetric display has been proposed that outputs projector light toward a reciprocating projection screen. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6716565 Summary of the Invention [Problem to be solved by the invention]

[0004] Volumetric displays generally display the interior of a volume so that the viewer can change their viewpoint. However, when observing a real, non-transparent object, the interior cannot be seen through the volumetric display, resulting in a discrepancy between the actual appearance and the actual object.

[0005] The present invention has been made in view of the above circumstances, and aims to provide a technique for improving the visibility of a stereoscopic image displayed by a volumetric display. [Means for solving the problem]

[0006] A display device according to one embodiment of the present invention comprises a display body formed by stacking a plurality of screens that can be switched between a transmission state that transmits light and a diffusion state that diffuses light, an irradiation unit that irradiates image display light toward the display body, a sensor that detects the position of an observer relative to the display body, and a control unit that synchronously controls the switching between the transmission state and the diffusion state of each of the plurality of screens and the switching of the display content of the image display light irradiated from the irradiation unit in accordance with the position of the observer detected by the sensor.

[0007] Another aspect of the display device of the present invention includes a display body formed by stacking a plurality of screens, each of the plurality of screens including a plurality of pixels arranged in an in-plane direction, each of the plurality of pixels being switchable between a transmission state and a diffusion state; an irradiation unit that irradiates image display light toward the display body; a sensor that detects the position of an observer relative to the display body; and a control unit that synchronously controls the switching between the transmission state and the diffusion state of each of the plurality of pixels of the plurality of screens and the switching of the display content of the image display light irradiated from the irradiation unit, depending on the position of the observer detected by the sensor.

[0008] A display method according to one aspect of the present invention includes the steps of: using a sensor to detect the position of an observer relative to a display body that includes a stack of multiple screens that can be switched between a transmission state that transmits light and a diffusion state that diffuses light; and synchronously controlling the switching between the transmission state and the diffusion state of each of the multiple screens and the switching of the display content of the image display light that is irradiated from an irradiation unit toward the display body, depending on the position of the observer detected by the sensor.

[0009] Another aspect of the display method of the present invention includes the steps of: detecting, using a sensor, the position of an observer relative to a display body having a plurality of stacked screens, each of the plurality of screens including a plurality of pixels arranged in an in-plane direction, each of the plurality of pixels being switchable between a transmission state and a diffusion state; and synchronously controlling, according to the position of the observer detected by the sensor, the switching between the transmission state and the diffusion state of each of the plurality of pixels of the plurality of screens and the switching of the display content of the image display light irradiated from an irradiation unit toward the display body.

[0010] A program according to one embodiment of the present invention is configured to cause a computer to execute the following functions: a function of using a sensor to detect the position of an observer relative to a display body that is made up of a plurality of stacked screens that can be switched between a transmission state that transmits light and a diffusion state that diffuses light; and a function of synchronously controlling the switching between the transmission state and the diffusion state of each of the plurality of screens and the switching of the display content of the image display light that is irradiated from an irradiation unit toward the display body, depending on the position of the observer detected by the sensor.

[0011] Another aspect of the present invention provides a program that causes a computer to execute the following functions: a function of detecting, using a sensor, the position of an observer relative to a display device formed by stacking a plurality of screens, each of the plurality of screens including a plurality of pixels arranged in an in-plane direction, each of the plurality of pixels being switchable between a transmission state and a diffusion state; and a function of synchronously controlling, according to the position of the observer detected by the sensor, the switching between the transmission state and the diffusion state of each of the plurality of pixels of the plurality of screens and the switching of the display content of the image display light that is irradiated from an irradiation unit toward the display device.

[0012] Any combination of the above components or mutual substitution of the components or expressions of the present invention between methods, devices, systems, etc. are also valid aspects of the present invention. [Effects of the Invention]

[0013] According to the present invention, it is possible to improve the visibility of a stereoscopic image displayed by a volumetric display. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram schematically illustrating a configuration of a display device according to a first embodiment. [Figure 2] FIG. 2 is a diagram schematically illustrating an example of the configuration of a screen. [Figure 3] FIG. 2 is a block diagram illustrating an example of a functional configuration of a control unit. [Figure 4] FIG. 2 is a diagram schematically illustrating an example of three-dimensional data. [Figure 5] 5(a) and 5(b) are diagrams showing an example of a display portion and a non-display portion. [Figure 6] FIG. 2 is a diagram illustrating a method for generating cross-sectional image data. [Figure 7] 7(a) to 7(f) are diagrams schematically showing examples of cross-sectional images. [Figure 8] 4 is a flowchart showing an example of a display method according to the first embodiment. [Figure 9] FIG. 9(a) is a diagram showing an example of a stereoscopic image displayed as seen by an observer according to a comparative example, and FIG. 9(b) is a diagram showing an example of a stereoscopic image displayed as seen by an observer according to an example. [Figure 10] FIG. 10 is a diagram schematically illustrating the configuration of a display device according to a second embodiment. [Figure 11] 11(a) to 11(c) are diagrams schematically showing a display method according to the second embodiment. [Figure 12] 10 is a flowchart showing an example of a display method according to the second embodiment. [Figure 13] FIG. 10 is a diagram schematically illustrating the configuration of a display device according to a third embodiment. [Figure 14] FIG. 10 is a cross-sectional view schematically showing a display method according to a third embodiment. [Figure 15] 10 is a flowchart showing an example of a display method according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Specific numerical values ​​and the like shown in the embodiments are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. Elements not directly related to the present invention are omitted from the drawings. To facilitate understanding of the description, the dimensional ratios of the components in the drawings do not necessarily correspond to the actual dimensional ratios.

[0016] (First embodiment) 1 is a diagram schematically illustrating the configuration of a display device 10 according to a first embodiment. The display device 10 includes a display body 12, an irradiation unit 14, a sensor 16, and a control unit 18. The display device 10 is a so-called volume display, and is configured to render a three-dimensional image S inside the display body 12 using three-dimensional data provided from an external device 20.

[0017] The display 12 includes a plurality of flat screens 22. The display 12 is configured by stacking the screens 22 in a direction (z direction) perpendicular to the in-plane directions (x direction and y direction) of each of the screens 22. The display 12 is configured to have a cylindrical, polygonal prism, or rectangular parallelepiped shape. The outer shape of each of the screens 22 is circular, polygonal, or rectangular. In the example shown in FIG. 1, the display 12 is rectangular parallelepiped, and the outer shape of each of the screens 22 is rectangular.

[0018] The number of the plurality of screens 22 is not particularly limited, but may be, for example, 10 or more, 100 or more, or 1000 or more. The number of the plurality of screens 22 determines the resolution in the z direction of the display body 12. On the other hand, the resolution in the x direction and y direction of the display body 12 is determined by the resolution of the image display light 24 irradiated from the irradiation unit 14.

[0019] The screen 22 is configured to be switchable between a transmissive state that transmits light and a diffusing state that diffuses light. The transmissive state refers to a state that is transparent to visible light, where incident visible light is transmitted as is and travels straight without being scattered. On the other hand, the diffusing state refers to a state that scatters incident visible light, where incident visible light is scattered in various directions. In the transmissive state, the screen 22 functions as a transparent plate with high transmittance for visible light. In the diffusing state, the screen 22 functions as a screen plate that scatters visible light.

[0020] FIG. 2 is a diagram schematically illustrating an example of the configuration of the screen 22. The screen 22 has a structure in which a first electrode layer 22a, a diffusion layer 22b, and a second electrode layer 22c are stacked. The first electrode layer 22a and the second electrode layer 22c are made of a material that is transparent to visible light, such as a transparent conductive material such as indium tin oxide (ITO). The diffusion layer 22b is configured to switch between a transmissive state and a diffusing state depending on whether or not a voltage is applied between the first electrode layer 22a and the second electrode layer 22c. The diffusion layer 22b is made of, for example, an electrochromic material or a liquid crystal material.

[0021] Returning to FIG. 1 , the irradiation unit 14 is configured to irradiate the display 12 with image display light 24. The irradiation unit 14 irradiates the image display light 24 in the stacking direction of the plurality of screens 22. The image display light 24 irradiated from the irradiation unit 14 is light that passes through the screen 22 in the transmissive state and is scattered by the screen 22 in the diffusing state. As a result, an image corresponding to the display content of the image display light 24 is displayed on the screen 22 in the diffusing state.

[0022] The irradiation unit 14 is, for example, a projector, and includes a light source that generates illumination light, an image display element that modulates the illumination light from the light source to generate image display light 24, and a projection optical system that projects the image display light 24. The image display element may be a transmissive display element such as a liquid crystal panel, or a reflective display element such as a DMD (Digital Mirror Device) or LCOS (Liquid Crystal on Silicon). The irradiation unit 14 may be a laser scanning projector that generates the image display light 24 by two-dimensionally scanning a laser beam. In this case, the image display element of the irradiation unit 14 may be a laser scanning module (LSM) such as a MEMS (Micro Electro Mechanical Systems) type.

[0023] The sensor 16 detects an observer 26 observing the display body 12. The sensor 16 is, for example, arranged at a position away from the display body 12 in the z direction, and detects the observer 26 present around the display body 12. The sensor 16 is, for example, an omnidirectional camera capable of capturing images of the display body 12 and a 360-degree area around the display body 12, and detects the position of the observer 26 relative to the display body 12 from the arrangement of the display body 12 and the observer 26 included in the image captured by the omnidirectional camera. The sensor 16 detects the position coordinates of the observer 26 in a coordinate system (e.g., x direction, y direction, and z direction) based on the center of the display body 12. The sensor 16 may be composed of multiple sensors arranged at multiple positions, or may be composed of multiple cameras with different positions and angles of view, for example.

[0024] The sensor 16 may be configured to further detect a viewpoint position 26a and a gaze direction 26b of the observer 26. The viewpoint position 26a of the observer 26 is the midpoint between the observer's 26 eyes when both eyes are detected, and is the position of the detected eye when only one eye of the observer 26 is detected. The gaze direction 26b of the observer 26 can be identified by detecting the direction of the observer's 26 eyes using a known technique. The direction of the observer's 26 eyes can be detected based on the difference in position between moving points such as the iris or pupil of the eye, which move when the eyeball is moved, and fixed points such as the inner corner or outer corner of the eye, which do not move even when the eyeball is moved.

[0025] The control unit 18 controls the overall operation of the display device 10. The various functions provided by the control unit 18 can be realized, for example, by a combination of hardware and software. The hardware of the control unit 18 is realized by elements and mechanical devices such as a processor and memory provided in a computer. The software of the control unit 18 is realized by a program executed by a processor, etc.

[0026] The external device 20 is an information processing device capable of generating three-dimensional data. Similar to the control unit 18, the external device 20 can be realized by a combination of hardware and software. The hardware of the external device 20 can be realized by elements or mechanical devices such as a processor or memory provided in a computer, and the software of the external device 20 can be realized by a program executed by a processor, etc.

[0027] 3 is a block diagram showing a schematic example of the functional configuration of the control unit 18. The control unit 18 includes a three-dimensional data acquisition unit 30, an observer position identification unit 32, a display data generation unit 34, a screen control unit 36, and an illumination control unit 38.

[0028] The three-dimensional data acquisition unit 30 acquires three-dimensional data from the external device 20. The three-dimensional data acquired from the external device 20 is data for specifying the three-dimensional shape of the three-dimensional image S to be displayed on the display body 12. The three-dimensional data may be three-dimensional contour image data that specifies the three-dimensional position and display color of the contour of the three-dimensional image S. The three-dimensional data may be video data, and may include frame data for drawing each frame of the three-dimensional image S that will become the video.

[0029] 4 is a diagram schematically illustrating an example of three-dimensional data, showing a case where the three-dimensional image S to be displayed on the display device 12 is a cone 40. The three-dimensional data includes data for specifying the three-dimensional positions and display colors of the cone surface (or side surface) 42 and bottom surface 44 that form the outline of the cone 40. The three-dimensional data is defined, for example, using a coordinate system (e.g., x direction, y direction, and z direction) based on the center of the display device 12.

[0030] Returning to FIG. 3 , the observer position identifying section 32 identifies the position of the observer 26 using information acquired from the sensor 16. For example, if the sensor 16 is a camera, the observer position identifying section 32 acquires an image captured by the sensor 16 and identifies the position of the observer 26 from the acquired captured image. The observer position identifying section 32 may acquire, from the sensor 16, the position coordinates of the observer 26 detected by the sensor 16. The observer position identifying section 32 may identify the viewpoint position 26a of the observer 26 or the line of sight direction 26b of the observer 26.

[0031] The display data generation unit 34 generates display data for displaying the stereoscopic image S, using the three-dimensional data acquired by the three-dimensional data acquisition unit 30 and the position of the observer 26 identified by the observer position identification unit 32. The display data generated by the display data generation unit 34 is used to control the operations of the display body 12 and the irradiation unit 14.

[0032] The display data generation unit 34 maps the three-dimensional shape of the stereoscopic image S based on the three-dimensional data and the position of the observer 26 in a coordinate system based on the center of the display body 12, and identifies the contour portions of the stereoscopic image S that are visible from the position of the observer 26. In other words, the display data generation unit 34 identifies the contour portions of the stereoscopic image S that are not visible from the position of the observer 26. Here, the visible contour portions are the portions of the contour of the stereoscopic image S that are directed toward the observer 26, and are the display portions that should be displayed as the stereoscopic image S. On the other hand, the invisible contour portions are the portions that are blocked by the display portions when viewed from the observer 26, and are the non-display portions that should not be displayed as the stereoscopic image S.

[0033] 5(a) and 5(b) are diagrams schematically illustrating an example of a display portion 46 and a non-display portion 48, in which the stereoscopic image S is the cone 40 shown in FIG. 4. FIG. 5(a) is a perspective view corresponding to FIG. 1, and FIG. 5(b) is a top view corresponding to the view from the sensor 16 of FIG. 1. In the example of FIGS. 5(a) and 5(b), the observer 26 is positioned on the −x-direction side of the cone 40, and the line of sight 26b of the observer 26 is directed in the +x-direction toward the cone 40. In this case, the cone surface 42a, which is the half of the cone 40 on the −x-direction side, is the display portion 46 visible from the viewpoint 26a of the observer 26. On the other hand, the cone surface 42b, which is the half of the cone 40 on the +x-direction side, and the bottom surface 44 of the cone 40 are the non-display portion 48 invisible from the viewpoint 26a of the observer 26. The non-display portion 48 is a portion that is blocked by the display portion 46 and cannot be seen when viewed from the viewpoint position 26a of the observer 26.

[0034] For example, the display data generation unit 34 sets a line segment 52 between a coordinate point 50 indicating the three-dimensional position of the outline of the cone 40 and the viewpoint position 26a, and determines whether the outline of the cone 40 exists on the line segment 52. If the outline of the cone 40 does not exist on the line segment 52, the coordinate point 50 is designated as the displayed portion 46. If the outline of the cone 40 exists on the line segment 52, the coordinate point 50 is designated as the hidden portion 48. The display data generation unit 34 determines whether all coordinate points indicating the three-dimensional position of the outline of the cone 40 belong to the displayed portion 46 or the hidden portion 48. In the example shown in FIGS. 5(a) and (b), another coordinate point 54 that is designated as the displayed portion 46 exists on the line segment 52, so the coordinate point 50 being determined is designated as the hidden portion 48.

[0035] The display data generation unit 34 may determine whether an area is a displayed area 46 or a hidden area 48, taking into consideration the range of the field of view of the observer 26. For example, the display data generation unit 34 may determine only coordinate points on a line segment 52 extending in a specific direction from the viewpoint position 26a as candidates for the displayed area 46, and may determine all coordinate points on a line segment 52 extending in a direction different from the specific direction as candidates for the hidden area 48. Here, the specific direction refers to a direction that falls within a predetermined angular range in each of the vertical and horizontal directions centered on the line of sight 26b of the observer 26. For example, based on the general range of human vision, a range that falls within a predetermined angular range in each of the vertical and horizontal directions centered on the line of sight 26b can be determined as the specific direction.

[0036] 6 is a diagram schematically illustrating a method for generating cross-sectional image data. The display data generation unit 34 generates multiple cross-sectional image data from three-dimensional data consisting only of the display portion 46. The display data generation unit 34 generates cross-sectional image data that indicate the shapes of cross-sectional portions 46a-46f of the display portion 46 in multiple xy planes 56a-56f that correspond to the z coordinate positions of the multiple screens 22. The multiple cross-sectional image data are display data for displaying images to be projected on each of the multiple screens 22.

[0037] Figures 7(a) to 7(f) are diagrams schematically illustrating examples of cross-sectional images, and show cross-sectional images corresponding to xy planes 56a to 56f, respectively, in Figure 6. As shown in Figures 7(a) to 7(f), cross-sectional portions 46a to 46f included in each of the multiple cross-sectional images have an arc shape corresponding to display portion 46, which corresponds to half of conical surface 42.

[0038] 3, the screen control unit 36 ​​controls the operation of the multiple screens 22 included in the display 12. The screen control unit 36 ​​sets one of the multiple screens 22 to a diffusion state and the remaining screens 22 to a transmission state. The screen control unit 36 ​​switches the screen 22 to be set to the diffusion state, and controls the multiple screens 22 so that each screen is set to the diffusion state in turn at different times.

[0039] The irradiation control unit 38 controls the operation of the irradiation unit 14. The irradiation control unit 38 controls the display content of the image display light 24 irradiated from the irradiation unit 14 using the display data generated by the display data generation unit 34. The irradiation control unit 38 switches the display content of the image display light 24 in synchronization with the operation of the screen control unit 36, so that the image display light 24 of the corresponding display content is irradiated onto each of the multiple screens 22. The irradiation control unit 38 switches the display content of the image display light 24 irradiated from the irradiation unit 14 using the multiple cross-sectional image data generated by the display data generation unit 34 in synchronization with the switching between the transmission state and the diffusion state of each of the multiple screens 22.

[0040] 8 is a flowchart showing an example of a display method according to the first embodiment. The three-dimensional data acquisition unit 30 acquires three-dimensional data from the external device 20 (S10). The observer position identification unit 32 detects the position of the observer 26 relative to the display body 12 using the sensor 16 (S12). The display data generation unit 34 identifies a display portion 46 and a non-display portion 48 of the three-dimensional data from the detected position of the observer 26 (S14), and generates multiple pieces of cross-sectional image data for displaying the identified display portion 46 (S16). The screen control unit 36 ​​switches between a transmission state and a diffusion state of the multiple screens 22 constituting the display body 12 (S18). The irradiation control unit 38 switches the display content of the image display light 24 irradiated from the irradiation unit 14 using the multiple pieces of cross-sectional image data generated by the display data generation unit 34 (S20).

[0041] The control unit 18 synchronizes and controls the switching of the states of the plurality of screens 22 by the screen control unit 36 ​​(S18) and the switching of the display content of the image display light 24 by the irradiation control unit 38 (S20). The cycle for switching the states of the plurality of screens 22 is, for example, on the order of several milliseconds, and the time required for switching all of the plurality of screens 22 is, for example, on the order of several tens to several hundreds of milliseconds. As a result, the display content displayed on each of the plurality of screens 22 in a time-division manner becomes an afterimage and is visually recognized by the observer 26 together, and a three-dimensional image S is generated on the display body 12. The irradiation control unit 38 controls the display content of the image display light 24 so that only a portion of the three-dimensional data acquired from the external device 20 that should be visible to the observer 26 is displayed as the three-dimensional image S. As a result, a three-dimensional image S can be displayed in such a way that the back side of the three-dimensional image S cannot be seen through when viewed by the observer 26.

[0042] FIG. 9(a) is a display example of a stereoscopic image S1 as seen by an observer 26 according to a comparative example, and FIG. 9(b) is a display example of a stereoscopic image S as seen by an observer 26 according to an example. In the comparative example of FIG. 9(a), the display portion 46 is not identified using the position of the observer 26, and the entire three-dimensional data acquired from the external device 20 is displayed as the stereoscopic image S1. In the comparative example of FIG. 9(a), the hidden portion 48 is also displayed as the stereoscopic image S1, so that the observer 26 can see through the non-displayed portion 48, which results in the portion 58 behind the cone 40. On the other hand, in the example of FIG. 9(b), display data for only the display portion 46 is used, so the back side of the cone 40 is hidden, and a display mode can be achieved in which the back side of the cone 40 is not visible to the observer 26.

[0043] The control unit 18 may acquire three-dimensional data corresponding to each frame of the video data from the external device 20 and display a different stereoscopic image S for each frame. This allows the display of a stereoscopic image S as a video. When the position of the observer 26 changes, the control unit 18 dynamically changes the portion of the three-dimensional data that is to be the display portion 46 and displays the stereoscopic image S. This makes it possible to achieve a display mode in which the back side of the stereoscopic image S is not visible when viewed from the observer 26, even when the position of the observer 26 changes.

[0044] (Second embodiment) 10 is a diagram schematically illustrating the configuration of a display device 60 according to a second embodiment. The second embodiment differs from the first embodiment in that each of the multiple screens 62 has a pixel structure. The following description of the second embodiment will focus on the differences with the first embodiment, and will omit a description of the commonalities as appropriate.

[0045] The display device 60 includes a display body 12, an irradiation unit 14, a sensor 16, and a control unit 18. The irradiation unit 14, the sensor 16, and the control unit 18 may be configured in the same manner as in the first embodiment.

[0046] The display 12 includes a plurality of screens 62 stacked in the z direction. The screens 62 include a plurality of pixels 64 arranged in the in-plane directions (x direction and y direction). The screens 62 are configured so that each pixel 64 can be switched between a transmissive state and a diffusing state. The screens 62 are configured so that some of the pixels 64 can be selectively switched to the diffusing state.

[0047] According to the second embodiment, since the screen 62 has a pixel structure, the display content of the image display light 24 can be displayed on the screen 62 by selectively setting some of the pixels 64 corresponding to the display content of the image display light 24 emitted from the irradiation unit 14 to a diffusion state. According to the second embodiment, the image display light 24 can be simultaneously irradiated onto two or more of the multiple screens 62, and the display content of the image display light 24 can be simultaneously displayed on the two or more screens 62. In each of the two or more screens 62, at least one pixel 64 that is located at a position that does not overlap in the irradiation direction of the image display light 24 is simultaneously set to a diffusion state.

[0048] 11(a) to 11(c) are diagrams schematically showing a display method according to the second embodiment, illustrating a case where pixels 66a and 66d of two or more screens 62a and 62d are simultaneously put into a diffusion state.

[0049] Figure 11(a) shows a control example of the first screen 62a corresponding to the first plane 56a in Figure 6. In the first screen 62a, pixels 66a overlapping with the first cross-sectional portion 46a are in a diffuse state, and pixels 68a not overlapping with the first cross-sectional portion 46a are in a transparent state. Figure 11(b) shows a control example of the fourth screen 62d corresponding to the fourth plane 56d in Figure 6. In the fourth screen 62d, pixels 66d overlapping with the fourth cross-sectional portion 46d are in a diffuse state, and pixels 68d not overlapping with the fourth cross-sectional portion 46d are in a transparent state.

[0050] In this case, the pixels 66a in the diffuse state on the first screen 62a do not overlap with the pixels 66d in the diffuse state on the fourth screen 62d in the stacking direction (z direction). In other words, the pixels 66a in the diffuse state on the first screen 62a overlap with the pixels 68d in the transmissive state on the fourth screen 62d in the stacking direction (z direction). Similarly, the pixels 66d in the diffuse state on the fourth screen 62d overlap with the pixels 68a in the transmissive state on the first screen 62a in the stacking direction (z direction).

[0051] 11(c) shows the display content of the image display light 24 irradiated onto the first screen 62a and the fourth screen 62d. The display content in FIG. 11(c) is an image in which the first cross-sectional portion 46a to be displayed on the first screen 62a and the fourth cross-sectional portion 46d to be displayed on the fourth screen 62d are superimposed. The first cross-sectional portion 46a is displayed on the diffused pixel 66a of the first screen 62a. The fourth cross-sectional portion 46d passes through the transparent pixel 68a of the first screen 62a and is displayed on the diffused pixel 66d of the fourth screen 62d.

[0052] 11(a) to 11(c) show the case where the first cross-sectional portion 46a and the fourth cross-sectional portion 46d of FIG. 6 are displayed simultaneously. By using similar control, the second cross-sectional portion 46b and the fifth cross-sectional portion 46e of FIG. 6 can be displayed simultaneously, and the third cross-sectional portion 46c and the sixth cross-sectional portion 46f of FIG. 6 can be displayed simultaneously. By displaying on two or more of the multiple screens 62 simultaneously in this manner, the time required for displaying on all of the multiple screens 62 can be shortened, and the frame rate at which the display of the three-dimensional image S is updated can be increased. For example, by displaying on two screens 62 simultaneously, the frame rate at which the display of the three-dimensional image S is updated can be doubled.

[0053] In the second embodiment, the display data generation unit 34 generates pixel pattern data for controlling the states of the plurality of pixels 64 of the screen 62. The pixel pattern data determines which of the plurality of pixels 64 are to be in a diffuse state and which are to be in a transparent state. For example, for the first screen 62a, pixel pattern data is generated that determines the pixel 66a in a diffuse state and the pixel 68a in a transparent state shown in FIG. 11(a). The pixel pattern data can be generated using the cross-sectional image data described in the first embodiment. For example, the pixel pattern data can be determined so that pixels in the cross-sectional image data where the display portion 46 is present are in a diffuse state and pixels in the cross-sectional image data where the display portion 46 is not present are in a diffuse state.

[0054] The display data generation unit 34 determines a combination of two or more pixel pattern data from among the plurality of pixel pattern data corresponding to the plurality of screens 62, such that the diffused pixels do not overlap each other. For example, the display data generation unit 34 determines a combination of pixel pattern data for the first screen 62a in FIG. 11(a) and pixel pattern data for the fourth screen 62d in FIG. 11(b). The display data generation unit 34 may determine combinations that minimize the number of pixel pattern data combinations. In this case, the time required to display all of the plurality of screens 62 can be further reduced. The display data generation unit 34 may include three or more pixel pattern data in one combination. Furthermore, for pixel pattern data for which no combination is found in which the diffused pixels do not overlap each other, the pixel pattern data may be left alone without being combined with other pixel pattern data.

[0055] The display data generation unit 34 generates display image data for controlling the display content of the image display light 24 emitted from the irradiation unit 14 based on a combination of pixel pattern data. The display data generation unit 34 generates display image data by superimposing multiple cross-sectional image data corresponding to the combination of pixel pattern data. For example, the display data generation unit 34 generates display image data corresponding to the display content of FIG. 11(c) based on a combination of pixel pattern data of the first screen 62a in FIG. 11(a) and pixel pattern data of the fourth screen 62d in FIG. 11(b). The display image data corresponding to FIG. 11(c) is generated by superimposing first cross-sectional image data corresponding to the display content of the first screen 62a and fourth cross-sectional image data corresponding to the display content of the fourth screen 62d.

[0056] The screen control unit 36 ​​controls switching between the transmissive state and the diffused state of the plurality of pixels 64 of the plurality of screens 62 based on the combination of pixel pattern data. When one combination includes two or more pixel pattern data, the screen control unit 36 ​​switches at least one pixel 64 included in each of the corresponding two or more screens 62 to the diffused state based on the pixel pattern data. The screen control unit 36 ​​controls the pixel patterns of each of the plurality of screens 62 in a time-division manner by switching between the combinations of pixel pattern data in order.

[0057] The illumination control unit 38 switches the display content of the image display light 24 in synchronization with the operation of the screen control unit 36. The illumination control unit 38 controls the display content of the image display light 24 emitted from the illumination unit 14 using display image data generated in accordance with a combination of pixel pattern data. The illumination control unit 38 controls the display content of each of the multiple screens 62 in a time-division manner by switching the display image data in sequence.

[0058] 12 is a flowchart showing an example of a display method according to the second embodiment. The three-dimensional data acquisition unit 30 acquires three-dimensional data from the external device 20 (S30). The observer position identification unit 32 detects the position of the observer 26 relative to the display body 12 using the sensor 16 (S32). The display data generation unit 34 identifies a display portion 46 and a non-display portion 48 of the three-dimensional data from the detected position of the observer 26 (S34), and generates a plurality of cross-sectional image data for displaying the identified display portion 46 (S36).

[0059] The display data generation unit 34 uses the multiple cross-sectional image data to generate multiple pixel pattern data that define the diffusion state and transmission state of multiple pixels 64 of the multiple screens 62 (S38). The display data generation unit 34 determines a combination of pixel pattern data from the multiple pixel pattern data such that pixels in the diffusion state do not overlap each other (S40). The display data generation unit 34 generates display image data by superimposing two or more cross-sectional image data corresponding to the combination of pixel pattern data (S42).

[0060] The screen control unit 36 ​​switches between the transmission state and the diffusion state of the plurality of pixels 64 of the plurality of screens 62 using the combination of image pattern data generated by the display data generation unit 34 (S44). The illumination control unit 38 switches the display content of the image display light 24 illuminated from the illumination unit 14 using the plurality of display image data generated by the display data generation unit 34 (S46).

[0061] The control unit 18 synchronizes and controls the screen control unit 36 ​​to switch the states of the plurality of pixels 64 of the plurality of screens 62 (S44) and the illumination control unit 38 to switch the display content of the image display light 24 (S46), thereby displaying a three-dimensional image S in such a way that the back side of the three-dimensional image S is not visible when viewed from the observer 26. In this case, by combining two or more pixel pattern data, the image display light 24 can be illuminated onto two or more screens 62 simultaneously, thereby reducing the time required to illuminate all of the plurality of screens 62 with the image display light 24 and display the three-dimensional image S.

[0062] (Third embodiment) 13 is a diagram schematically illustrating the configuration of a display device 70 according to a third embodiment. The following description of the third embodiment will focus on the differences from the second embodiment, and will omit a description of the commonalities as appropriate.

[0063] The display device 70 includes a display 12, an irradiation unit 14, a sensor 16, and a control unit 18. The display 12 includes a plurality of screens 62 having a pixel structure, similar to the second embodiment. The irradiation unit 14, the sensor 16, and the control unit 18 may be configured similarly to the first embodiment.

[0064] The sensor 16 detects the positions of multiple observers 26, 76. The sensor 16 is configured to detect, for example, a viewpoint position 26a and a line of sight direction 26b of a first observer 26, and also to detect a viewpoint position 76a and a line of sight direction 76b of a second observer 76. In the example shown in Fig. 13, two observers are detected simultaneously, but three or more observers may be detected simultaneously.

[0065] In the third embodiment, a display mode is realized in which the back side of the stereoscopic image S is difficult to see through for multiple observers 26, 76 present around the display body 12. In the third embodiment, if the portion corresponding to the back side of the stereoscopic image S as seen by the first observer 26 is hidden, the portion corresponding to the front side of the stereoscopic image S as seen by the second observer 76 will also be hidden, making it impossible to display an appropriate stereoscopic image S to the second observer 76. Therefore, in the third embodiment, it may be inappropriate to hide a portion of the stereoscopic image S in order to realize a display mode in which the back side of the stereoscopic image S is difficult to see through. In the third embodiment, diffused pixels of the screen 62 are used to block light from the portion corresponding to the back side of the stereoscopic image S as seen by the multiple observers 26, 76, thereby realizing a display mode in which the back side of the stereoscopic image S is difficult to see through.

[0066] Fig. 14 is a cross-sectional view schematically illustrating a display method according to the third embodiment. Fig. 14 illustrates a situation in which the first screen 62a is in a diffusion state and is irradiated with image display light 24. A first display portion 80 and a second display portion 82, which form the outline of the stereoscopic image S, are displayed on the first screen 62a. The first display portion 80 is the front side of the stereoscopic image S as viewed by the first observer 26, and the back side of the stereoscopic image S as viewed by the second observer 76. The second display portion 82 is the back side of the stereoscopic image S as viewed by the first observer 26, and the front side of the stereoscopic image S as viewed by the second observer 76.

[0067] 14, the multiple screens 62a to 62f are controlled so that pixels on a first line 84 extending from the first display portion 80 to the first observer 26 are set to a transparent state, so that the first observer 26 can view the first display portion 80. For example, a pixel 94 located at the intersection of the first line 84 and the second screen 62b is controlled to a transparent state. Similarly, pixels on a second line 86 extending from the second display portion 82 to the second observer 76 are controlled to a transparent state, so that the second observer 76 can view the second display portion 82. For example, a pixel 96 located at the intersection of the second line 86 and the second screen 62b is controlled to a transparent state.

[0068] 14 , the screens 62a to 62f are controlled so that at least one pixel on a third line 88 extending from the second display portion 82 toward the first observer 26 is in a diffused state, making it difficult for the first observer 26 to view the second display portion 82. For example, a pixel 98 located at the intersection of the third line 88 and the third screen 62c is controlled to be in a diffused state. Similarly, at least one pixel on a fourth line 90 extending from the first display portion 80 toward the second observer 76 is controlled to be in a diffused state, making it difficult for the second observer 76 to view the first display portion 80. For example, a pixel 100 located at the intersection of the fourth line 90 and the third screen 62c is controlled to be in a diffused state. Note that a pixel 92 located at the intersection of the third line 88 and the fourth line 90 and the second screen 62b may also be controlled to be in a diffused state. To improve the shielding effect of the diffused pixels, a plurality of pixels 92, 98 on the third line 88 may be simultaneously put into the diffused state, and a plurality of pixels 92, 100 on the fourth line 90 may be simultaneously put into the diffused state.

[0069] In the third embodiment, the display data generation unit 34 identifies a plurality of display portions 80, 82 corresponding to a plurality of observers 26, 76. For example, the display data generation unit 34 identifies a portion that should be displayed as seen by the first observer 26 as the first display portion 80, and a portion that should be displayed as seen by the second observer 76 as the second display portion 82. The display data generation unit 34 identifies a portion of the plurality of display portions 80, 82 that should be shielded from the plurality of observers 26, 76. For example, the display data generation unit 34 identifies a display portion other than the first display portion 80 (e.g., the second display portion 82) as the first shielded portion that should be shielded from the first observer 26, and identifies a display portion other than the second display portion 82 (e.g., the first display portion 80) as the second shielded portion that should be shielded from the second observer 76.

[0070] The display data generation unit 34 generates cross-sectional image data for displaying the multiple display portions 80, 82 for each of the multiple screens 62. When image display light 24 based on the cross-sectional image data is irradiated onto one screen 62, the display data generation unit 34 generates pixel pattern data that determines the transmission state and diffusion state of the multiple pixels 64 of the remaining screens 62. For example, pixel pattern data for screens other than the first screen 62a (e.g., the second screen 62b and the third screen 62c) is generated as pixel pattern data used when image display light 24 based on the first cross-sectional image data is irradiated onto the first screen 62a. The pixel pattern data for the screens other than the first screen 62a is determined so that pixels on a straight line extending from the display portions 80, 82 toward the corresponding observers 26, 76 are in a transmission state, and at least one pixel on a straight line extending from the shielding portions 82, 80 toward the corresponding observers 26, 76 is in a diffusion state. For example, pixels on a line extending from the first display portion 80 toward the first observer 26 are in a transparent state, pixels on a line extending from the second display portion 82 toward the second observer 76 are in a transparent state, at least one pixel on a line extending from the first shielding portion 82 toward the first observer 26 is in a diffuse state, and at least one pixel on a line extending from the second shielding portion 80 toward the second observer 76 is in a diffuse state.

[0071] The screen control unit 36 ​​controls switching between the transmission state and the diffusion state of the plurality of pixels 64 of the plurality of screens 62 based on the pixel pattern data. For example, the screen control unit 36 ​​sets all pixels 64 of the screen 62 that is the target of irradiation with the image display light 24 to the diffusion state, and controls the transmission state and the diffusion state of the plurality of pixels 64 of the screens 62 other than the target of irradiation based on the pixel pattern data. For example, when the display content of the image display light 24 is displayed on the first screen 62a, at least some of the pixels 64 of the screens 62b to 62f other than the first screen 62a are controlled to the diffusion state based on the pixel pattern data. Furthermore, when the display content of the image display light 24 is displayed on the second screen 62b, at least some of the pixels 64 of the screens 62a, 62c to 62f other than the second screen 62b are controlled to the diffusion state based on the pixel pattern data.

[0072] The irradiation control unit 38 switches the display content of the image display light 24 in synchronization with the operation of the screen control unit 36. The irradiation control unit 38 uses the generated cross-sectional image data to control the display content of the image display light 24 irradiated from the irradiation unit 14. The irradiation control unit 38 controls the display content of each of the multiple screens 62 in a time-division manner by switching the cross-sectional image data in sequence.

[0073] According to the third embodiment, by using pixels in a diffused state to block or scatter light from the back side of the three-dimensional image S as seen by each of the multiple observers 26, 76, a display mode can be realized in which the back side of the three-dimensional image S is less visible through the pixels.

[0074] 15 is a flowchart showing an example of a display method according to the third embodiment. The three-dimensional data acquisition unit 30 acquires three-dimensional data from the external device 20 (S50). The observer position identification unit 32 detects the positions of multiple observers 26, 76 relative to the display body 12 using the sensor 16 (S52). The display data generation unit 34 identifies display portions 80, 82 and shielded portions 82, 80 of the three-dimensional data from the detected positions of the multiple observers 26, 76 (S54), and generates multiple cross-sectional image data for displaying the identified display portions 80, 82 (S56). The display data generation unit 34 generates pixel pattern data for transmitting light from the identified display portions 80, 82 toward the corresponding observers 26, 76 and for shielding light from the identified shielded portions 82, 80 toward the corresponding observers 26, 76 (S58). The screen control unit 36 ​​switches between a transmission state and a diffusion state of the plurality of pixels 64 of the plurality of screens 62 using the pixel pattern data generated by the display data generation unit 34 (S60). The illumination control unit 38 switches the display content of the image display light 24 emitted from the illumination unit 14 using the display image data generated by the display data generation unit 34 (S62). The control unit 18 controls the switching of the states of the plurality of pixels 64 of the plurality of screens 62 by the screen control unit 36 ​​(S60) and the switching of the display content of the image display light 24 by the illumination control unit 38 (S62) in a synchronized manner. This makes it possible to display the three-dimensional image S in a manner that makes it difficult for the back side of the three-dimensional image S to be seen through when viewed by the plurality of observers 26, 76.

[0075] The present invention has been described above with reference to the above-mentioned embodiments, but the present invention is not limited to the above-mentioned embodiments, and appropriate combinations or substitutions of the configurations shown in each display example are also included in the present invention. [Explanation of symbols]

[0076] 10, 60, 70...display device, 12...display body, 14...illumination unit, 16...sensor, 18...control unit, 22, 62...screen, 24...image display light, 26...observer, 30...three-dimensional data acquisition unit, 32...observer position identification unit, 34...display data generation unit, 36...screen control unit, 38...illumination control unit, 46...display portion, 48...non-display portion, 64...pixels

Claims

1. a display body formed by stacking a plurality of screens that can be switched between a light transmitting state and a light diffusing state; an irradiation unit that irradiates image display light toward the display; a sensor for detecting the position of a viewer relative to the display; a control unit that, in accordance with the position of the observer detected by the sensor and three-dimensional data indicating the three-dimensional shape of the three-dimensional image to be displayed on the display body, identifies a portion of the three-dimensional image that is visible to the observer as a display portion included in the display content of the image display light, and identifies a portion of the three-dimensional image that is not visible to the observer as a non-display portion not included in the display content of the image display light, and synchronously controls the switching between the transmission state and the diffusion state of each of the multiple screens and the switching of the display content of the image display light irradiated from the irradiation unit.

2. a display body in which a plurality of screens are stacked, each of the plurality of screens including a plurality of pixels arranged in an in-plane direction, the plurality of pixels being switchable between a transmission state and a diffusion state for each pixel; an irradiation unit that irradiates image display light toward the display; a sensor for detecting the position of a viewer relative to the display; a control unit that synchronizes and controls switching between the transmission state and the diffusion state of each of the plurality of pixels of the plurality of screens and switching of the display content of the image display light irradiated from the irradiation unit, in accordance with the position of the observer detected by the sensor.

3. 3. The display device according to claim 2, wherein the control unit simultaneously causes at least one pixel included in each of two or more of the plurality of screens to be in a diffused state in accordance with at least one of the position of the viewer detected by the sensor and the display content of the image display light irradiated from the irradiation unit.

4. a step of detecting, using a sensor, the position of a viewer relative to a display body in which a plurality of screens that can be switched between a transmission state in which light is transmitted and a diffusion state in which light is diffused are stacked; a step of specifying a portion of the three-dimensional image that is visible to the observer as a display portion included in the display content of the image display light, and specifying a portion of the three-dimensional image that is not visible to the observer as a non-display portion not included in the display content of the image display light, in accordance with the position of the observer detected by the sensor and three-dimensional data that indicates the three-dimensional shape of the three-dimensional image to be displayed on the display body, and a step of synchronously controlling switching between the transmission state and the diffusion state of each of the plurality of screens and switching of the display content of the image display light that is irradiated from an irradiation unit toward the display body.

5. a step of detecting, using a sensor, the position of a viewer relative to a display body in which a plurality of screens are stacked, each of the plurality of screens including a plurality of pixels arranged in an in-plane direction, each of the plurality of pixels being switchable between a transmission state and a diffusion state; and controlling, in accordance with the position of the observer detected by the sensor, switching between the transmission state and the diffusion state of each of the plurality of pixels of the plurality of screens and switching of the display content of the image display light irradiated from an irradiation unit toward the display body, in a synchronized manner.

6. a function of detecting, using a sensor, the position of a viewer relative to a display body formed by stacking multiple screens that can be switched between a transmission state that transmits light and a diffusion state that diffuses light; a program configured to cause a computer to execute a function of specifying a portion of the three-dimensional image that is visible to the observer as a display portion included in the display content of the image display light, and specifying a portion of the three-dimensional image that is not visible to the observer as a non-display portion not included in the display content of the image display light, in accordance with the position of the observer detected by the sensor and three-dimensional data that indicates the three-dimensional shape of the three-dimensional image to be displayed on the display body; and a function of synchronously controlling the switching between the transmission state and the diffusion state of each of the plurality of screens and the switching of the display content of the image display light that is irradiated from an irradiation unit toward the display body.

7. a function of detecting, using a sensor, the position of a viewer relative to a display body in which a plurality of screens are stacked, each of the plurality of screens including a plurality of pixels arranged in an in-plane direction, each of the plurality of pixels being switchable between a transmission state and a diffusion state; and a function of synchronously controlling switching between the transmission state and the diffusion state of each of the plurality of pixels of the plurality of screens and switching of the display content of the image display light irradiated from the irradiation unit toward the display body, in accordance with the position of the observer detected by the sensor.

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