Spatial image display system

Abstract

This spatial image display system for displaying an object as a spatial image by using integral photography (IP) technology includes: (a) an IP image converter that converts a captured image obtained by capturing the object from a plurality of viewpoints into an element image group in which a plurality of element images 15 required for displaying the spatial image constitute one set; and (b) a spatial image display 12 integrating: an IP image panel 17 that displays an IP image 21 composed of the plurality of element images 15 of the element image group on a display surface 20 in which a plurality of pixels are arranged in a matrix; and an IP filter 18 disposed in front of the display surface 20 of the IP image panel 17 and having light-transmissive parts 24 at positions corresponding to the respective center portions of the plurality of element images 15 on the IP image 21 as seen in a front view.

Description

Spatial image display system

[0001] The present invention relates to a spatial image display system that, by using integral photography (IP) technology, can display (reproduce) clear spatial images (three-dimensional (stereoscopic) images and two-dimensional images) that can be viewed by an observer with the same sense of perception as in everyday life, without the need for special glasses.

[0002] Conventionally, among various spatial image display methods, the IP method, which displays a spatial image using data (images) that record the optical spatial image of an object, is considered an ideal method for displaying spatial images. Here, the principle of the IP method will be explained. As shown in Figure 14, a light-shielding panel 51 is placed in front of a three-dimensional object (object) 50 at a predetermined interval. Multiple (in this case, three) pinholes 52a to 52c are formed in this light-shielding panel 51. Further in front of the light-shielding panel 51, a photosensitive film 53 is placed parallel to the light-shielding panel 51. There are countless object points on the surface of the three-dimensional object 50 that emit (reflect) light, but here we will focus on three object points 54 to 56. Of the countless rays of light emitted in various directions from each object point 54 to 56, one ray 54a, 55a, and 56a each passes through the pinhole 52a, forming an elemental image 60a consisting of minute images 57a, 58a, and 59a on the photosensitive film 53. Similarly, from the countless rays of light emitted in various directions from each object point 54-56, one ray 54b, 55b, and 56b each passes through the pinhole 52b, forming an elemental image 60b consisting of minute images 57b, 58b, and 59b on the photosensitive film 53, and one ray 54c, 55c, and 56c each passes through the pinhole 52c, forming an elemental image 60c consisting of minute images 57c, 58c, and 59c on the photosensitive film 53. In the IP-type spatial image display method and spatial image display device, an IP image 61 composed of elemental images 60a' to 60c' obtained by inverting these elemental images 60a to 60c by 180 degrees relative to the pinholes 52a to 52c is displayed on a display (image display panel). As a result, by observing the direction of arrow a, the observer will see the light emitted from each elemental image 60a' to 60c' through the pinholes 52a to 52c. In actual spatial image display devices, by increasing the number of pinholes (arranging them at a high density), observers can observe a three-dimensional image (real image) of a three-dimensional object 50 with its surface details accurately represented through countless pinholes.

[0003] As a spatial image (stereoscopic image) display device employing this IP method, for example, Patent Document 1 proposes a stereoscopic image display device having a display in which small images (element images) having multiple minute images in each divided section are displayed, a shutter panel arranged in front of the display having a first mechanical shutter arranged in order of minute image units and switched on and off in order of minute image units to time-divide each section for each small image, and an imaging panel arranged in order of imaging means (second mechanical shutter) that images the light from each small image that passes through when the first mechanical shutter is on, each small image has an imaging means, each small image consists of multiple minute images arranged in a distributed manner, and each imaging means is on an axis passing through the central region of the corresponding small image. Furthermore, Patent Document 1 describes how a first mechanical shutter is turned on and off (opened and closed) in units of minute images, and each section is time-divided into small images. This allows for the rapid and sequential selection and extraction of light emitted by multiple small images in each section, thereby sharpening the three-dimensional image and enabling video playback. In addition, Patent Document 1 describes how an imaging means is provided for each small image to allow the light emitted by each small image to pass through. Each imaging means is positioned on an axis passing through the central region of the corresponding small image. This allows for the extraction of light emitted by each small image, which is selected in time division and whose display range (position) changes within each section, from the central region of each small image, thereby reducing distortion of the three-dimensional image and suppressing a decrease in light intensity.

[0004] International Publication No. 2020 / 122053

[0005] However, Patent Document 1 has the problem that, in order to sequentially select one small image at a time from among multiple small images in each section at high speed, the first mechanical shutter and imaging means (second mechanical shutter) must be driven in a time-division manner, resulting in a complex structure and control, high cost, and difficulty in scaling up the device. In addition, there is the problem that it is time-consuming to create the image data that forms the basis of the multiple small images displayed in each section, and as the device becomes larger and the capacity of the image data increases, data processing takes time, making it difficult to display smooth video.

[0006] This invention has been made in view of the above circumstances, and aims to provide a spatial image display system that has a simple structure, does not require complicated control, can display a spatial image that can be viewed by the observer with the same sense as in everyday life without using special glasses, and is easy to scale up.

[0007] A spatial image display system according to the present invention that is in line with the above objective is a spatial image display system that displays an object as a spatial image using IP technology, and comprises: (a) an IP image converter that converts captured images obtained by photographing the object from multiple viewpoints into a group of element images, each consisting of multiple element images necessary for displaying the spatial image; and (b) an IP image panel that displays an IP image composed of multiple element images of the group of element images on a display surface configured by arranging multiple pixels vertically and horizontally; and an IP filter that is positioned in front of the display surface of the IP image panel and has one light-transmitting portion at a position corresponding to the center of each of the multiple element images on the IP image when viewed from the front, and integrates these two components.

[0008] Here, the object can be either a planar image (two-dimensional image) or a three-dimensional image. If the object is, for example, an image displayed on an image display device such as a display, then the planar image (two-dimensional image) is displayed as the spatial image. If the object is any kind of three-dimensional object, then the three-dimensional image is displayed as the spatial image. A liquid crystal panel (liquid crystal display) is preferably used as the IP image panel, but it is not limited to this. The shape of each pixel of the IP image panel may be square or rectangular when viewed from the front. If the shape of each pixel of the IP image panel is square when viewed from the front, then the length of one side of each pixel is the vertical pitch P of the multiple pixels arranged vertically and horizontally. ｐｙ and lateral pitch P ｐｘ (=P ｐｙ ) becomes equal to. An IP filter only needs to allow light to pass through in the light-transmitting portion, while the rest of the filter is light-shielding. An IP filter can be obtained, for example, by forming a light-transmitting portion in a light-shielding plate. Alternatively, a liquid crystal or PDLC (dimmable film) type light shutter that can switch (adjust) between a transparent state and an opaque state depending on whether or not voltage is applied may be used as an IP filter. A liquid crystal or PDLC type light shutter can make a desired position (region) transparent, thereby allowing that transparent region to function as a light-transmitting portion.

[0009] In the spatial image display system according to the present invention, the plurality of element images on the IP image are each configured in a rectangular shape with vertical dimension a and horizontal dimension b when viewed from the front, by the plurality of pixels of the IP image panel, and are arranged vertically and horizontally, and the light-transmitting portion is formed in the shape of a pinhole with a vertical pitch P ａ = a, lateral pitch P ｂ The elements are arranged vertically and horizontally at =b, and the distance g from the display surface of the IP image panel to the IP filter is the vertical pitch P of the light-transmitting portion. ａ and the lateral pitch P ｂ It is preferable that the value be in the range of 0.5 to 5 times (more preferably 1 to 2 times).

[0010] Here, when viewed from the front, each of the plurality of elemental images on the IP image may be square or rectangular. For example, in the case where each pixel of the IP image panel is square when viewed from the front, and each elemental image is configured by n (n is an integer of 1 or more) pixels vertically and n horizontally, the shape of each elemental image is such that when viewed from the front, the side length a (=b) is the vertical pitch P of the pixels of the IP image panel ｐｙ (= horizontal pitch P ｐｘ ) multiplied by n, and each light-transmitting part is arranged at equal intervals vertically and horizontally corresponding to the position of the center of each elemental image, and the vertical pitch P thereof ａ (= horizontal pitch P ｂ ) is equal to the side length a (=b) of each elemental image, and is n times the vertical pitch P of the pixels of the IP image panel ｐｙ (= horizontal pitch P ｐｘ ).

[0011] In the aerial image display system according to the present invention, the plurality of elemental images on the IP image each have a horizontal width W when viewed from the front by the plurality of pixels of the IP image panel, are configured in a rectangular shape whose vertical dimension is equal to the vertical dimension of the display surface, and are arranged side by side horizontally; the light-transmitting parts are formed in a vertically elongated slit shape and arranged side by side horizontally at a horizontal pitch P Ｗ =W, and the distance g from the display surface of the IP image panel to the IP filter is preferably in the range of 0.5 to 5 times (more preferably 1 to 2 times) the horizontal pitch P of the light-transmitting parts Ｗ .

[0012] In the aerial image display system according to the present invention, the object is a CG image, and it is preferable that the photographed image and the plurality of elemental images are generated through calculation by the IP image converter on the assumption that the object is virtually photographed by a camera. Here, the CG image may be an image such as a wireframe created using a computer from the beginning, or may be obtained by converting a actually photographed image into a CG image.

[0013] In the aerial image display system according to the present invention, the aerial image display device is composed of a plurality of aerial image display elements arranged vertically and horizontally, and each of the plurality of aerial image display elements comprises: a unit image display section obtained by dividing the IP image panel into units of the element images on the IP image; and a unit image light-transmitting section obtained by dividing the IP filter into units of the element images on the IP image, and is preferably partitioned from other adjacent aerial image display elements by a partition section. Here, each aerial image display element is formed independently, and an aerial image display device can be obtained by arranging and integrating a plurality of aerial image display elements vertically and horizontally on a plane.

[0014] In the aerial image display system according to the present invention, the unit image display section can be bent or curved to function as the partition section. Here, by bending or curving the unit image display section and causing part or all of the unit image display section to function as the partition section, there is no need to separately provide a partition section. Further, by bending or curving the unit image display section, the area of the display surface of the IP image panel can be increased.

[0015] In the aerial image display system according to the present invention, the aerial image display device is composed of a plurality of linear aerial image display elements arranged in a column direction or a row direction, and each of the plurality of linear aerial image display elements comprises: a linear image display section obtained by dividing the IP image panel in row units or column units of the IP image; and a linear image light-transmitting section obtained by dividing the IP filter in row units or column units of the IP image, and may be partitioned from other adjacent linear aerial image display elements by a partition section. Here, each linear aerial image display element is formed independently, and an aerial image display device can be obtained by arranging and integrating a plurality of linear aerial image display elements in the column direction or the row direction on a plane.

[0016] In the aerial image display system according to the present invention, the linear image display section can be bent or curved to function as the partition section.

[0017] Here, by bending or curving the linear image display section and causing a part or the whole thereof to function as the partition section, it is not necessary to separately provide a partition section. Further, by bending or curving the linear image display section, the area of the display surface of the IP image panel can be increased. In the aerial image display system according to the present invention, the system may comprise a plurality of said IP image converters, a plurality of said aerial image displays provided one for each of the plurality of IP image converters, and a control section that controls the plurality of IP image converters, wherein the plurality of aerial image displays are arranged vertically and horizontally and seamlessly joined together to form an aerial image display device. Here, the IP image that is the base of the aerial image is divided and displayed on the respective IP image panels of the plurality of aerial image displays. Accordingly, one IP image can be distributed and processed by the plurality of IP image converters, the amount of data processed by each IP image converter can be reduced to increase processing speed, and an increase in size of the aerial image display device and smooth moving image display can be realized.

[0018] In the spatial image display system according to the present invention, the IP image converter generates a first IP image and a second IP image composed of two different groups of element images, and the IP image panel displays the first IP image and the second IP image simultaneously such that the pixels constituting each of the plurality of element images included in the first IP image and the pixels constituting each of the plurality of element images included in the second IP image do not overlap, and the spatial image display device is (a) positioned between the IP image panel and the IP filter, and the light emitted from the first IP image is first The system may also include: (b) a polarization unit that linearly polarizes light emitted from the second IP image in a direction, and linearly polarizes the light emitted from the second IP image in a second direction perpendicular to the first direction; (c) a first linear polarization filter provided corresponding to the light-transmitting portion located at the center of each of the plurality of element images included in the first IP image when viewed from the front, and which allows only light linearly polarized in the first direction to pass through; and (d) a second linear polarization filter provided corresponding to the light-transmitting portion located at the center of each of the plurality of element images included in the second IP image when viewed from the front, and which allows only light linearly polarized in the second direction to pass through.

[0019] Here, the IP image panel only needs to display images (a first IP image and a second IP image) using light linearly polarized in one direction, and a conventionally known liquid crystal panel (liquid crystal display) can be used as such an IP image panel. Generally, the images displayed on the IP image panel are linearly polarized in one direction parallel to the vertical or horizontal direction of the display surface when viewed from the front. In this case, it is preferable to set the first direction or the second direction in the polarization unit parallel to the direction of linear polarization in the IP image panel. The polarization direction of the first linear polarization filter is set to match the first direction, and the polarization direction of the second linear polarization filter is set to match the second direction. As a result, the light-transmitting section covered with the first linear polarization filter can pass only the light emitted from the first IP image (light linearly polarized in the first direction by the polarization unit), and the light-transmitting section covered with the second linear polarization filter can pass only the light emitted from the second IP image (light linearly polarized in the second direction by the polarization unit). Therefore, when the first IP image and the second IP image are displayed simultaneously on a single IP image panel, the light emitted from the first IP image and the light emitted from the second IP image can each pass through different light-transmitting sections.

[0020] In the spatial image display system according to the present invention, the IP image converter generates a first IP image and a second IP image composed of two different groups of element images, and the IP image panel displays the first IP image and the second IP image simultaneously such that the pixels constituting each of the plurality of element images included in the first IP image and the pixels constituting each of the plurality of element images included in the second IP image do not overlap, and the spatial image display unit includes (a) a polarization unit disposed between the IP image panel and the IP filter which linearly polarizes the light emitted from the first IP image in a first direction and the light emitted from the second IP image in a second direction perpendicular to the first direction, and (b) a polarization unit disposed on the light-emitting surface side of the IP filter, The IP filter comprises a polarizer having a polarization axis parallel to direction 1, and the IP filter functions as a first light-transmitting area in a region that overlaps with one or more pixels located at the center of each of the multiple element images included in the first IP image when viewed from the front, allowing light linearly polarized in the first direction by the polarization unit and light linearly polarized in the second direction by the polarization unit to pass through as is; and functions as a second light-transmitting area in a region that overlaps with one or more pixels located at the center of each of the multiple element images included in the second IP image when viewed from the front, allowing light linearly polarized in the first direction by the polarization unit to pass through after being linearly polarized in the second direction, and light linearly polarized in the second direction by the polarization unit to pass through after being linearly polarized in the first direction.

[0021] Here, the polarization unit and IP filter may use a dynamic optical element that allows the user to select (switch) on a pixel-by-pixel basis of the IP image (first IP image and second IP image) which region allows the incident light to pass through without changing (rotating) its polarization direction, and which region allows the light to pass through after changing (rotating) its polarization direction by 90 degrees. Alternatively, the polarizing unit and IP filter may use a static optical element in which the region allowing the incident light to pass through without changing (rotating) its polarization direction, and which region allows the light to pass through after changing (rotating) its polarization direction by 90 degrees, are predetermined to be fixed on a pixel-by-pixel, row-by-row, or column-by-column basis of the IP image (first IP image and second IP image). Preferably, the dynamic optical element is one that can change the orientation direction of liquid crystal molecules by the presence or absence of voltage application, thereby allowing the user to select whether or not to change (rotate) the polarization direction of the light passing through it by 90 degrees. Preferably, the static optical element is one that utilizes the properties of a λ / 2 wave plate to change (rotate) the polarization direction of only the light passing through a predetermined region selected in advance by 90 degrees, but is not limited to these.

[0022] In the spatial image display system according to the present invention, the polarization unit comprises a first polarization orientation film, a second polarization orientation film positioned opposite the first polarization orientation film, a polarizing liquid crystal layer made of liquid crystal filled between the first polarization orientation film and the second polarization orientation film, and a polarization drive unit capable of switching the orientation direction of the liquid crystal molecules in the polarizing liquid crystal layer on a pixel-by-pixel basis, wherein the orientation processing direction of the first polarization orientation film and the orientation processing direction of the second polarization orientation film are orthogonal to each other.

[0023] In the spatial image display system according to the present invention, the IP filter comprises a first alignment film for shutters, a second alignment film for shutters positioned opposite the first alignment film for shutters, a liquid crystal layer for shutters made of liquid crystal filled between the first alignment film for shutters and the second alignment film for shutters in areas that function as at least the first and second light-transmitting areas, a shutter drive unit capable of switching the orientation direction of the liquid crystal molecules in the liquid crystal layer for shutters on a pixel-by-pixel basis, and a shielding portion that shields areas other than the areas that function as the first and second light-transmitting areas of the liquid crystal layer for shutters, wherein the orientation processing direction of the first alignment film for shutters and the orientation processing direction of the second alignment film for shutters are orthogonal to each other.

[0024] In the spatial image display system according to the present invention, the structure of the spatial image display unit can be simplified, there is no need for complicated control, the device can be made larger and the display speed can be increased, and the observer can observe a clear spatial image by viewing the light emitted from the IP image displayed on the IP image panel through the light-transmitting part of the IP filter.

[0025] This is an explanatory diagram showing the configuration of a spatial image display system according to the first embodiment of the present invention. (A) is a front view of the main part of the spatial image display unit in the spatial image display system, and (B) is a cross-sectional view taken along the line A-A in (A). (A) is a front view of the main part of the IP image panel of the spatial image display unit in the spatial image display system, and (B) is a partially enlarged front view of the IP image panel of the spatial image display unit in the spatial image display system. (A) is a front view showing an example of a spatial image display element constituting the spatial image display unit in the spatial image display system, (B) is a side view showing an example of a spatial image display element constituting the spatial image display unit in the spatial image display system, and (C) is a cross-sectional view taken along the line B-B in (A). (A) is a front view showing an example of a linear spatial image display element constituting the spatial image display unit in the spatial image display system, (B) is a plan view showing an example of a linear spatial image display element constituting the spatial image display unit in the spatial image display system, and (C) is a cross-sectional view taken along the line C-C in (A). This is an explanatory diagram showing the operation of a spatial image display in a spatial image display system according to a second embodiment of the present invention. This is a schematic exploded perspective view of the main parts showing the configuration of the spatial image display in the spatial image display system. This is a front view of the main parts showing the spatial image display in the spatial image display system. This is a front view of the main parts of the spatial image display in a spatial image display system according to a third embodiment of the present invention. This is an explanatory diagram showing the operation of a spatial image display in a spatial image display system according to a fourth embodiment of the present invention. This is a front view of the main parts showing the spatial image display in the spatial image display system. This is a schematic exploded perspective view of the main parts showing the configuration of the spatial image display in a spatial image display system according to a fifth embodiment of the present invention. This is a schematic cross-sectional view of the main parts showing the operation of the spatial image display in the spatial image display system. This is an explanatory diagram showing the principle of the IP method (spatial image reproduction method).

[0026] Next, with reference to the attached drawings, an embodiment of the present invention will be described to facilitate understanding of the present invention. The spatial image display system 10 according to the first embodiment of the present invention shown in Figure 1 displays an object as a spatial image using IP technology. This spatial image display system 10 basically consists of an IP image converter 11 and a spatial image display unit 12. In this embodiment, the spatial image display system 10 has a plurality of (in this case, nine) IP image converters 11, a plurality of (in this case, nine) spatial image display units 12, one of which is provided corresponding to each of the plurality of IP image converters 11, and a control unit 13 that controls the plurality of IP image converters 11. The plurality of spatial image display units 12 are arranged vertically and horizontally and seamlessly connected to form a large spatial image display device 14.

[0027] The IP image converter 11 converts captured images obtained by photographing an object from multiple viewpoints into a group of elemental images, each consisting of multiple elemental images 15 (see Figures 3(A) and (B)) necessary for displaying a spatial image. The principle for generating multiple elemental images 15 from an object is explained in Figure 14, but a computer graphics (CG) image is preferably used as the object, and the IP image converter 11 can generate the captured image and the multiple elemental images 15 by calculation, assuming that the object is photographed by a virtual camera in the three-dimensional space of the CG image. In this case, the captured image can be considered as an image obtained by moving a monocular camera and photographing the object at each position (viewpoint), or as an image obtained by fixing a compound camera and photographing the object simultaneously with multiple lenses (multiple viewpoints).

[0028] As shown in Figures 2(A) and 2(B), the spatial image display unit 12 integrates an IP image panel 17 and an IP filter 18. The IP image panel 17 shown in Figure 3(A) has a display surface 20 composed of multiple pixels 19 arranged vertically and horizontally, as shown in Figure 3(B). The IP image panel 17 displays an IP image 21 on its display surface 20, in which multiple element images 15 of an element image group are arranged vertically and horizontally. Each of the multiple element images 15 on the IP image 21 is composed of multiple pixels 19 of the IP image panel 17 and is arranged vertically and horizontally without gaps. In this embodiment, as shown in Figure 3(B), the area in which one element image 15 is displayed contains 20 pixels 19 in both the vertical and horizontal directions, which are square when viewed from the front, and the vertical dimension a of the element image 15 is equal to the horizontal dimension b, and the vertical pitch P of the pixels of the IP image panel 17 ｐｙ (= lateral pitch P) ｐｘ This is 20 times the previous amount.

[0029] As shown in Figures 2(A) and (B), the IP filter 18 is a light-shielding plate 23 positioned in front of the display surface 20 of the IP image panel 17, with one pinhole-shaped light-transmitting portion 24 formed on each of the multiple element images 15 on the IP image 21, when viewed from the front. In this embodiment, since one element image 15 is a square composed of 20 pixels 19 vertically and horizontally, the vertical pitch P of the light-transmitting portion 24 ａ The transverse pitch P of the light-transmitting portion 24 ｂ Equal to the vertical dimension a and horizontal dimension b of the element image 15 (= vertical pitch and horizontal pitch of the element image 15), and equal to the vertical pitch P of the pixels of the IP image panel 17. ｐｙ (= lateral pitch P) ｐｘ This is 20 times the normal distance. The distance g from the display surface 20 of the IP image panel 17 to the IP filter 18 is equal to the vertical pitch P of the light-transmitting section 24. ａ (= lateral pitch P) ｂ It is preferable that the pore diameter D of the pinhole-shaped light-transmitting portion 24 is in the range of 0.5 to 5 times (more preferably 1 to 2 times). Ｈ P is the vertical pitch of the pixels. ｐｙ (= lateral pitch P) ｐｘIt is preferable that it be about 1 to 2 times the above, but it is not limited to this range. Note that the vertical dimension a (= horizontal dimension b) of the element image 15 and the vertical pitch P of the light-transmitting portion 24 ａ (= lateral pitch P) ｂ The vertical and horizontal dimensions of the pixels (= vertical pitch P) are selected as appropriate, and accordingly, the number of pixels 19 included in the element image 15 is also selected as appropriate. Furthermore, the pixels and element images only need to be configured in a rectangular shape (including squares and rectangles) when viewed from the front, and the vertical and horizontal dimensions of the pixels (= vertical pitch P) are also selected. ｐｙ and horizontal pitch P ｐｘ ) and the vertical dimension a and horizontal dimension b of the element image (= vertical pitch P of the light-transmitting part) ａ and horizontal pitch P ｂ ) will be selected as appropriate.

[0030] The IP image panel 17 and the IP filter 18 can be integrated by surrounding their outer periphery with a frame (not shown). In this case, it is preferable to divide the space formed between the IP image panel 17 and the IP filter 18 vertically and horizontally (in a grid pattern) with partitions 25 for each element image 15. This allows the outer periphery of the display area of ​​each element image 15 to be surrounded by partitions 25, preventing light emitted from other adjacent element images 15 from entering the inside of the display area of ​​each element image 15, thereby improving the quality of the spatial image.

[0031] With the spatial image display system 10 configured as described above, the light emitted from each of the multiple element images 15 on the IP image 21 displayed on the display surface 20 of the IP image panel 17 passes through the light-transmitting portion 24 of the IP filter 18, allowing the observer to observe a spatial image (three-dimensional image or two-dimensional image) of the object. In this embodiment, multiple spatial image display devices 12 are arranged vertically and horizontally and seamlessly connected to enlarge the spatial image display device 14, and one IP image converter 11 is provided for each of the multiple spatial image display devices 12. As a result, when a single IP image 21, which is the basis of the spatial image, is divided and displayed on each of the IP image panels 17 of the multiple spatial image display devices 12, the processing can be distributed among the multiple IP image converters 11. Therefore, the amount of data processed by each IP image converter 11 is reduced, the processing speed is increased, and even in a large spatial image display device 14, high-quality spatial images can be displayed, and spatial images can be switched in a short time (for example, 30 to 240 frames / second), making it possible to display smooth video.

[0032] A conventionally known computer is preferably used as the IP image converter 11. The control unit 13 that controls the multiple IP image converters 11 is a host computer, and the control unit 13 transmits segmented CG image data, obtained by dividing the CG image that forms the basis of the IP image 21 into segments for each spatial image display unit 12, to each IP image converter 11. As described above, each IP image converter 11 converts the received segmented CG image data into multiple element images 15 and generates segmented IP images to be displayed on each spatial image display unit 12. By displaying each segmented IP image on each spatial image display unit 12, a single IP image 21 can be displayed on the entire spatial image display device 14. The method of connecting the control unit 13 and the multiple IP image converters 11 is not particularly limited and may be wired or wireless (internet, etc.). The segmented CG image data transmitted from the control unit 13 to the IP image converters 11 may be still image data or video data.

[0033] In this embodiment, a 165-inch spatial image display device 14 was realized by using nine 55-inch spatial image displays 12. The 55-inch spatial image displays 12 in this case have a resolution of 2,160 pixels vertically and 3,840 pixels horizontally, with each pixel measuring 0.315 mm vertically and horizontally. Furthermore, the vertical pitch P of the light-transmitting section 24... ａ (= lateral pitch P) ｂ The width of the spatial image display unit 12 is 6.3 mm, and the number of light-transmitting sections 24 provided on one spatial image display unit 12 is 108 vertically x 192 horizontally. The size of the spatial image display unit 12, the number of pixels, the pixel size, the pitch of the light-transmitting sections 24, the number of spatial image display units 12 constituting the spatial image display device 14, and the size of the spatial image display device 14 are not limited to this embodiment and can be selected as appropriate.

[0034] The spatial image display unit 12 may be composed of spatial image display elements 26 as shown in Figures 4(A) to (C). The spatial image display element 26 has a unit image display unit 27 obtained by dividing the IP image panel 17 into units of element images 15, and a unit image light-transmitting unit 28 obtained by dividing the IP filter 18 into units of element images 15. The spatial image display unit 12 can be obtained by arranging a plurality of spatial image display elements 26 vertically and horizontally on a plane and integrating them. In the spatial image display element 26, as shown in Figure 4(C), the area of ​​the image display surface 29 is enlarged by bending the unit image display unit 27 into a V-shape when viewed from above. The element images 15 displayed on the unit image display unit 27 are generated taking into consideration that the image display surface 29 of the unit image display unit 27 is bent into a V-shape.

[0035] The spatial image display element 26 can function not only as part of the IP image panel 17 that displays each element image 15, with the unit image display section 27 bent in a V-shape, but also as a partition between adjacent spatial image display elements 26. The unit image display section 27 can also be rotated 90 degrees around the light-transmitting section 24 when viewed from the front, and used with its vertical and horizontal orientations reversed. In addition, Figures 4(A) to (C) illustrate a spatial image display element 26 in which the unit image display section 27 is bent in a V-shape when viewed from above as an example, but the shape of the unit image display section 27 is not limited to this, and it may be planar, bent into a pyramidal shape, curved into a U-shape or semi-circular arc when viewed from above, or curved into a hemisphere.

[0036] Next, the spatial image display unit 12 may be composed of linear spatial image display elements 26A as shown in Figures 5(A) to (C). The linear spatial image display element 26A has a linear image display section 27A obtained by dividing the IP image panel 17 into row units or column units of the IP image 21, and a linear image light-transmitting section 28A obtained by dividing the IP filter 18 into row units or column units of the IP image 21. The spatial image display unit 12 can be obtained by arranging a plurality of linear spatial image display elements 26A in a row direction or row direction on a plane and integrating them. In the linear spatial image display element 26A, as shown in Figure 5(C), the area of ​​the image display surface 29A is increased by curving the linear image display section 27A in a U-shape or semi-circular arc shape when viewed from the side. The element images 15 displayed on the linear image display section 27A are generated taking into consideration that the image display surface 29A of the linear image display section 27A is curved in a U-shape or semi-circular arc shape.

[0037] The linear spatial image display element 26A can function not only as part of the IP image panel 17 that displays element images 15 in row units or column units using a U-shaped or semi-circular curved linear image display unit 27A, but also as a partition between adjacent linear image display units 27A. In Figures 5(A) to (C), a linear spatial image display element 26A is shown as an example, with the linear image display unit 27A curved in a U-shape or semi-circular curve when viewed from the side. However, the shape of the linear image display unit 27A is not limited to this; it may be planar, or, for example, bent into a V-shape when viewed from the side.

[0038] Next, with reference to Figures 6 to 8, the spatial image display unit 12A of the spatial image display system according to the second embodiment of the present invention will be described. Note that components similar to those in the first embodiment are denoted by the same reference numerals and their descriptions are omitted. The differences between the spatial image display unit 12A and the spatial image display unit 12A are that, as shown in Figure 6, the IP image panel 17A simultaneously displays a first IP image 21A (right-diagonal hatching area) and a second IP image 21B (left-diagonal hatching area); as shown in Figure 7, it includes a polarization unit 30 that linearly polarizes light emitted from the first IP image 21A in a first direction and linearly polarizes light emitted from the second IP image 21B in a second direction perpendicular to the first direction; and as shown in Figures 7 and 8, it includes a first linear polarization filter 31a that allows only light emitted from the first IP image 21A to pass through, and a second linear polarization filter 31b that allows only light emitted from the second IP image 21B to pass through. Furthermore, the IP image panel 17A and the polarizing unit 30 are arranged in close contact with each other.

[0039] The first IP image 21A and the second IP image 21B are generated by the IP image converter 11 and consist of two different sets of element images. As shown in Figure 6, the IP image panel 17A is arranged so that the pixels 19 constituting each of the multiple element images 15A included in the first IP image 21A and the pixels 19 constituting each of the multiple element images 15B included in the second IP image 21B do not overlap with each other, thereby enabling the simultaneous display of the first IP image 21A (right diagonal hatching area) and the second IP image 21B (left diagonal hatching area). At this time, the first IP image 21A and the second IP image 21B emit light linearly polarized in a first direction. Here, light emitted from images displayed on conventionally known liquid crystal panels (liquid crystal displays) is generally linearly polarized in one direction parallel to the vertical or horizontal direction of the display surface when viewed from the front. Therefore, by using an existing liquid crystal panel as the IP image panel 17A, the first IP image 21A and the second IP image 21B can be displayed using linearly polarized light such that the direction parallel to the vertical or horizontal direction of the display surface 20 is the first direction.

[0040] In this embodiment, as shown in Figure 6, each area where element image 15A and element image 15B are displayed contains four pixels 19 vertically and horizontally, and element image 15A and element image 15B are displayed offset by two pixels vertically and horizontally. In this embodiment, the pixels 19 that make up element image 15A and element image 15B are arranged in a checkerboard pattern (alternating) with an offset of one pixel vertically and horizontally so that they do not overlap with each other, but these arrangements are not limited to this embodiment and can be selected as appropriate.

[0041] Here, the IP filter 18A causes the light-transmitting portion located at the center of each of the multiple element images 15A included in the first IP image 21A to function as the first light-transmitting portion 24A, and the light-transmitting portion located at the center of each of the multiple element images 15B included in the second IP image 21B to function as the second light-transmitting portion 24B. Since the element images 15A are square when viewed from the front, the vertical pitch P of the first light-transmitting portion 24A ａ The lateral pitch P of the first light-transmitting section 24A is ｂEqual to the vertical dimension a and horizontal dimension b of the element image 15A (= vertical pitch and horizontal pitch of the element image 15A), and equal to the vertical pitch P of the pixels 19 of the IP image panel 17A. ｐｙ (= lateral pitch P) ｐｘ ) is four times larger. Similarly, since the element image 15B is square when viewed from the front, the vertical pitch P of the second light-transmitting part 24B ａ The lateral pitch P of the second light-transmitting section 24B is ｂ Equal to the vertical dimension a and horizontal dimension b of element image 15B (= vertical pitch and horizontal pitch of element image 15A), and equal to the vertical pitch P of the pixels 19 of IP image panel 17A. ｐｙ (= lateral pitch P) ｐｘ ) is four times larger. The first light-transmitting section 24A and the second light-transmitting section 24B of the IP filter 18A correspond to the center positions of the element images 15A and 15B respectively, and the vertical pitch P of the first light-transmitting section 24A and the second light-transmitting section 24B is such that they are aligned vertically and horizontally. ａ (= lateral pitch P) ｂ The elements are positioned offset by half a pixel each (two pixels each). Note that the vertical dimension a (= horizontal dimension b) of the element images 15A and 15B and the vertical pitch P of the first translucent section 24A and the second translucent section 24B are as follows. ａ (= lateral pitch P) ｂ The vertical and horizontal dimensions of the pixels (= vertical pitch P) are selected as appropriate, and accordingly, the number of pixels 19 included in element images 15A and 15B is also selected as appropriate. Furthermore, each pixel and element image only needs to be configured as a rectangular shape (including squares and rectangles) when viewed from the front, and the vertical and horizontal dimensions of the pixels (= vertical pitch P) are also selected. ｐｙ and horizontal pitch P ｐｘ ) and the vertical dimension a and horizontal dimension b of the element image (= vertical pitch P of the light-transmitting part) ａ and horizontal pitch P ｂ ) will be selected as appropriate.

[0042] As shown in Figure 7, the polarization unit 30 is positioned between the IP image panel 17A and the IP filter 18A and includes a first polarization alignment film 32a, a second polarization alignment film 32b positioned opposite the first polarization alignment film 32a, and a polarization liquid crystal layer 33 made of liquid crystal (not shown) filled between the first polarization alignment film 32a and the second polarization alignment film 32b. The polarization unit 30 also includes a polarization drive unit 34 that can switch the orientation direction of the liquid crystal molecules in the polarization liquid crystal layer 33 on a pixel-by-pixel basis. The polarization drive unit 34 includes an upper electrode 34a positioned on the light-receiving side (IP image panel 17A side) of the first polarization alignment film 32a and a lower electrode 34b positioned on the light-emitting side (light-shielding plate 23 side) of the second polarization alignment film 32b.

[0043] The upper electrode 34a and the lower electrode 34b are formed by creating transparent electrodes 35a and 35b on a transparent substrate, respectively. The transparent electrode 35a of the upper electrode 34a and the transparent electrode 35b of the lower electrode 34b are arranged orthogonally. This allows for selective switching of the voltage on and off (presence or absence of voltage application) for the liquid crystal molecules of the polarizing liquid crystal layer 33 at a pixel-by-pixel level of 19 units. Furthermore, the orientation processing direction of the first polarizing alignment film 32a and the orientation processing direction of the second polarizing alignment film 32b are orthogonal to each other. Specifically, the orientation grooves 36a formed in the first polarizing alignment film 32a and the orientation grooves 36b of the second polarizing alignment film 32b are arranged orthogonally.

[0044] When the voltage between the upper electrode 34a and the lower electrode 34b is off (no voltage applied), the liquid crystal molecules of the polarizing liquid crystal layer 33 sandwiched between the first polarizing alignment film 32a and the second polarizing alignment film 32b align along the alignment groove 36a on the side of the first polarizing alignment film 32a and align along the alignment groove 36b on the side of the second polarizing alignment film 32b. As a result, when the voltage between the upper electrode 34a and the lower electrode 34b is off (no voltage applied), the alignment direction of the liquid crystal molecules of the polarizing liquid crystal layer 33 sandwiched between the first polarizing alignment film 32a and the second polarizing alignment film 32b is gradually twisted from the first polarizing alignment film 32a toward the second polarizing alignment film 32b, and is finally twisted by 90 degrees. In this way, light passing through the polarizing liquid crystal layer 33, in which the alignment direction of the liquid crystal molecules is twisted by 90 degrees, is twisted by 90 degrees along the alignment direction of the liquid crystal molecules. As a result, the direction of linear polarization changes (rotates) by 90 degrees before and after passing through the polarizing liquid crystal layer 33.

[0045] In contrast, when the voltage between the upper electrode 34a and the lower electrode 34b is ON (voltage applied), the liquid crystal molecules sandwiched between the first polarizing alignment film 32a and the second polarizing alignment film 32b align in an upright position (along the electric field) perpendicular to the first polarizing alignment film 32a and the second polarizing alignment film 32b. Thus, light passing through the polarizing liquid crystal layer 33, where the alignment direction of the liquid crystal molecules is perpendicular to the first polarizing alignment film 32a and the second polarizing alignment film 32b, travels in a straight line along the alignment direction of the liquid crystal molecules, and therefore the direction of linear polarization does not change before and after passing through the polarizing liquid crystal layer 33.

[0046] The structure of the polarization drive unit 34 in the polarization unit 30 can be appropriately selected and used from structures similar to those of conventionally known drive units in liquid crystal displays. In this embodiment, the transparent electrodes 35a are arranged along the column direction (vertically) and the transparent electrodes 35b are arranged along the row direction (horizontally), but the arrangement of transparent electrodes 35a and 35b may be reversed. In this embodiment, a simple matrix drive method is used as the drive method for the polarization drive unit 34, but an active matrix drive method (TFT) may also be used. In this embodiment, the alignment groove 36a of the first polarization alignment film 32a is horizontal and the alignment groove 36b of the second polarization alignment film 32b is vertical, but the arrangement direction of the alignment grooves 36a and 36b is not limited to this, and it is sufficient if the alignment grooves 36a and 36b are orthogonal.

[0047] As explained earlier, when the voltage between the upper electrode 34a and the lower electrode 34b is off (no voltage applied), the direction of linear polarization changes by 90 degrees before and after passing through the polarizing liquid crystal layer 33. When the voltage between the upper electrode 34a and the lower electrode 34b is on (voltage applied), the direction of linear polarization does not change before and after passing through the polarizing liquid crystal layer 33. In this embodiment, since linearly polarized light is emitted from the first IP image 21A and the second IP image 21B, the polarization unit 30 can turn on (apply voltage) the voltage between the upper electrode 34a and the lower electrode 34b corresponding to the pixels 19 used to display the first IP image 21A, and turn off (do not apply voltage) the voltage between the upper electrode 34a and the lower electrode 34b corresponding to the pixels 19 used to display the second IP image 21B. This will cause the light emitted from the first IP image 21A to be linearly polarized in the first direction (more precisely, the light linearly polarized in the first direction to pass through as is), and the light emitted from the second IP image 21B to be linearly polarized in a second direction perpendicular to the first direction.

[0048] As shown in Figure 8, the first linear polarizing filter 31a is provided corresponding to the first light-transmitting portion 24A located at the center of each of the multiple element images 15A (see Figure 6) included in the first IP image 21A, and the second linear polarizing filter 31b is provided corresponding to the second light-transmitting portion 24B located at the center of each of the multiple element images 15B (see Figure 6) included in the second IP image 21B. The first linear polarizing filter 31a has a polarization axis (not shown) parallel to the first direction, and the second linear polarizing filter 31b has a polarization axis (not shown) parallel to the second direction. Light emitted from the first IP image 21A (linearly polarized light in the first direction) and light emitted from the second IP image 21B (linearly polarized light in the second direction) enter both the first light-transmitting section 24A and the second light-transmitting section 24B. However, the first linear polarization filter 31a and the second linear polarization filter 31b only allow light that is linearly polarized in a direction parallel to their respective polarization axes to pass through. Therefore, ultimately, only light emitted from the first IP image 21A is emitted from the first light-transmitting section 24A, and only light emitted from the second IP image 21B is emitted from the second light-transmitting section 24B. As a result, the observer can observe a bright, high-definition spatial image formed by combining the first IP image 21A and the second IP image 21B.

[0049] In this embodiment, the first linear polarizing filter 31a and the second linear polarizing filter 31b are arranged alternately in horizontal stripes. However, the first linear polarizing filter 31a and the second linear polarizing filter 31b only need to be provided corresponding to the first light-transmitting section 24A and the second light-transmitting section 24B, respectively. The shape, size, and arrangement of the first linear polarizing filter 31a and the second linear polarizing filter 31b can be selected as appropriate. For example, the first linear polarizing filter 31a and the second linear polarizing filter 31b may be arranged alternately in vertical stripes, or they may be divided into units smaller than rows or columns. In this embodiment, both the first linear polarizing filter 31a and the second linear polarizing filter 31b are placed on the light-emitting side (front side) of the IP filter 18A (light-shielding plate 23). However, they may also be placed on the light-receiving side (back side = polarizing unit 30 side) of the IP filter 18A, or one of them may be placed on the light-emitting side of the IP filter 18A and the other on the light-receiving side.

[0050] Next, with reference to Figure 9, the spatial image display unit 12B of the spatial image display system according to the third embodiment of the present invention will be described. Note that components similar to those in the first and second embodiments are denoted by the same reference numerals and their descriptions are omitted. The difference between the spatial image display unit 12B and the spatial image display unit 12 is, as shown in Figure 9, that the light-transmitting portion 24C is formed in the shape of a vertically elongated slit, and that the multiple element images 15C are arranged horizontally in a rectangular shape, with a horizontal dimension W equal to the vertical dimension of the display surface 20 when viewed from the front. Each light-transmitting portion 24C is positioned at a location corresponding to the center (widthwise center) of each of the multiple element images 15C on the IP image 21C when viewed from the front. Therefore, the horizontal pitch P of the light-transmitting portions 24C Ｗ This is equal to the horizontal dimension W of the element image 15C. The width D of the slit-shaped light-transmitting portion 24C. Ｗ The horizontal pitch P of pixel 19 is ｐｘ It is preferable that it be about 1 to 2 times, but it is not limited to this range. Also, the vertical dimension of the light-transmitting portion 24C is equal to the vertical dimension of the display surface 20, similar to the vertical dimension of the element image 15C.

[0051] The above-mentioned multiple element images 15C can be generated, for example, by placing a virtual camera facing (directly facing) the CG image of the object at the center of the CG image in the height direction, moving it horizontally from one side to the other in the width direction of the CG image (for example, from the left end to the right end), capturing vertically elongated images (slit images) from multiple viewpoints, and converting the obtained captured images into a set of element images by the IP image converter 11. The horizontal dimension W of the element image 15C and the horizontal pitch P of the light-transmitting portion 24C are specified. Ｗ The appropriate number of pixels is selected accordingly, and the number of pixels 19 included in the element image 15C is also selected accordingly.

[0052] As explained above, in the spatial image display 12, the rectangular element images 15 and the pinhole-shaped light-transmitting sections 24 are arranged two-dimensionally, vertically and horizontally, respectively. In contrast, in the spatial image display 12B, the vertically elongated rectangular element images 15C and the slit-shaped light-transmitting sections 24C, which are formed in a vertical shape equal to the vertical dimension of the display surface 20 of the IP image panel 17, are arranged one-dimensionally, horizontally. Therefore, the spatial image display 12B has a wider vertical viewing angle and a higher brightness of the spatial image compared to the spatial image display 12. Furthermore, in the spatial image display 12B, the configuration of the IP image 21C is simplified compared to the spatial image display 12, and the number of element images 15C is reduced, thereby reducing the load on the IP image converter 11, improving processing speed, and improving display speed. Moreover, the IP filter 18B having the slit-shaped light-transmitting sections 24C is easier to manufacture and has superior mass-producibility compared to the IP filter 18 having the pinhole-shaped light-transmitting sections 24. From the above, an inexpensive spatial image display system can be realized by using spatial image display unit 12B instead of spatial image display unit 12. In this embodiment, the element image 15C is formed in a vertically elongated rectangular shape and the light-transmitting portion 24C is formed in a vertically elongated slit shape, but the element image may be formed in a horizontally elongated rectangular shape and the light-transmitting portion may be formed in a horizontally elongated slit shape. In addition, the spatial image display unit 12B can be rotated 90 degrees to swap its vertical and horizontal orientation for use.

[0053] Next, with reference to Figures 10 and 11, the spatial image display unit 12C of the spatial image display system according to the fourth embodiment of the present invention will be described. Note that components similar to those in the first to third embodiments are denoted by the same reference numerals and their descriptions are omitted. The differences between the spatial image display unit 12C and the spatial image display unit 12A are, as shown in Figure 10, that each of the multiple element images 15D constituting the first IP image 21D and the multiple element images 15E constituting the second IP image 21E, which are simultaneously displayed by the IP image panel 17A, is formed in a vertically elongated rectangular shape when viewed from the front, and the IP filter 18C includes a plurality of first light-transmitting sections 24D formed in a vertically elongated slit shape corresponding to the plurality of element images 15D and a plurality of second light-transmitting sections 24E formed in a vertically elongated slit shape corresponding to the plurality of element images 15E.

[0054] Furthermore, the spatial image display unit 12C is equipped with the same polarization unit 30 (see Figure 7) as the spatial image display unit 12A, and can linearly polarize the light emitted from the first IP image 21D (each element image 15D) in a first direction (more precisely, it can pass light that is linearly polarized in the first direction as is), and linearly polarize the light emitted from the second IP image 21E (each element image 15E) in a second direction perpendicular to the first direction.

[0055] The first IP image 21D and the second IP image 21E are generated by the IP image converter 11 and consist of two different sets of elemental images. As shown in Figure 10, the IP image panel 17A can simultaneously display the first IP image 21D and the second IP image 21E by arranging the pixels 19 that make up each of the multiple elemental images 15D included in the first IP image 21D (right-diagonal hatching area) and the pixels 19 that make up each of the multiple elemental images 15E included in the second IP image 21E (left-diagonal hatching area) so that they do not overlap. At this time, the first IP image 21D and the second IP image 21E emit light that is linearly polarized in a first direction.

[0056] In this embodiment, each area where element image 15D and element image 15E are displayed contains four pixels 19 in the horizontal direction (width direction), and element image 15D and element image 15E are displayed with a horizontal (width direction) offset of two pixels each. In this embodiment, the pixels 19 that make up element image 15D and element image 15E are arranged alternately in a striped pattern (vertical stripes) with a horizontal offset of one pixel each so as not to overlap with each other, but these arrangements are not limited to this embodiment and can be selected as appropriate.

[0057] Here, the lateral pitch P of the first translucent portion 24D located at the center (widthwise center) of each of the multiple element images 15D contained in the first IP image 21D is Ｗ This is equal to the horizontal dimension W of the element image 15D (= horizontal pitch of the element image 15D), and the horizontal pitch P of the pixels 19 of the IP image panel 17A. ｐｘ It is four times that. Similarly, the lateral pitch P of the second translucent portion 24E located at the center (widthwise center) of each of the multiple element images 15E included in the second IP image 21E Ｗ This is equal to the horizontal dimension W of the element image 15E (= horizontal pitch of the element image 15E), and the horizontal pitch P of the pixels 19 of the IP image panel 17A. ｐｘ This is four times greater. The first light-transmitting section 24D and the second light-transmitting section 24E of the IP filter 18C correspond to the respective center positions (widthwise center) of the element image 15D and element image 15E, and the lateral pitch P of the first light-transmitting section 24D and the second light-transmitting section 24E Ｗ They are positioned with a horizontal shift of half a pixel each (two pixels each).

[0058] In this embodiment, the width D of the slit-shaped first light-transmitting portion 24D and the second light-transmitting portion 24E Ｗ However, the horizontal dimension of the pixel (= horizontal pitch P) ｐｘ ) is equal to but is not limited to this, and is appropriately selected according to the horizontal dimension W of the element images 15D and 15E. Also, the horizontal dimension W of the element images 15D and 15E and the horizontal pitch P of the first translucent portion 24D and the second translucent portion 24E. ＷThese are selected as appropriate, and accordingly, the number of pixels 19 included in the element images 15D and 15E is also selected as appropriate. The vertical dimensions of the first light-transmitting section 24D and the second light-transmitting section 24E are the same as the vertical dimensions of the element images 15D and 15E, and are equal to the vertical dimensions of the display surface 20 of the IP image panel 17A.

[0059] As shown in Figure 11, the first linear polarizing filter 31a is provided corresponding to the first light-transmitting portion 24D located at the center (widthwise center) of each of the multiple element images 15D (see Figure 9) included in the first IP image 21D, and the second linear polarizing filter 31b is provided corresponding to the second light-transmitting portion 24E located at the center (widthwise center) of each of the multiple element images 15E (see Figure 9) included in the second IP image 21E. The first linear polarizing filter 31a has a polarization axis (not shown) parallel to a first direction which is the same as the polarization direction of the first IP image 21D, and the second linear polarizing filter 31b has a polarization axis (not shown) parallel to a second direction which is the same as the polarization direction of the second IP image 21E.

[0060] With the above configuration, the first linear polarization filter 31a can allow only light linearly polarized in the first direction to pass through, and the second linear polarization filter 31b can allow only light linearly polarized in the second direction to pass through. Therefore, ultimately, only light emitted from the first IP image 21D is emitted from the first light-transmitting section 24D, and only light emitted from the second IP image 21E is emitted from the second light-transmitting section 24E. As a result, the spatial image display 12C has a simple configuration in which element images 15D and 15E are arranged one-dimensionally, and the first light-transmitting section 24D and the second light-transmitting section 24E are formed in a slit shape, yet it can form a bright, high-definition spatial image by combining the first IP image 21D and the second IP image 21E.

[0061] Next, with reference to Figures 12 and 13, the spatial image display unit 12D of the spatial image display system according to the fifth embodiment of the present invention will be described. Note that components similar to those in the first to fourth embodiments are denoted by the same reference numerals and their descriptions are omitted. The differences between the spatial image display unit 12D and the spatial image display unit 12A are, as shown in Figures 12 and 13, that instead of the IP filter 18A having a first light-transmitting portion 24A and a second light-transmitting portion 24B formed on the light-shielding plate 23, it is equipped with a liquid crystal shutter type IP filter 18D whose polarization direction can be selected (switched), and that instead of the first linear polarizing filter 31a and the second linear polarizing filter 31b, it is equipped with a polarizer 31c.

[0062] The IP filter 18D shown in Figure 13 functions as a first light-transmitting section 24F, where, when viewed from the front, the area overlapping with one or more pixels 19 located at the center of each of the multiple element images 15A included in the first IP image 21A allows light linearly polarized in a first direction by the polarization unit 30 and light linearly polarized in a second direction by the polarization unit 30 to pass through as is. The second light-transmitting section 24G functions as a second light-transmitting section 24G, where light linearly polarized in a first direction by the polarization unit 30 is linearly polarized in a second direction and passes through, and light linearly polarized in a second direction by the polarization unit 30 is linearly polarized in a first direction and passes through. In Figure 13, the direction of linear polarization in the first IP image 21A, the second IP image 21B, and the polarization unit 30 is represented by the direction of the hatching, with the first direction being the horizontal direction and the second direction being the vertical direction. Also, for illustrative purposes, in Figure 13, the IP image panel 17A and the polarization unit 30 are positioned apart, but in reality, they are positioned in close contact.

[0063] Next, the specific configuration of the IP filter 18D will be described. As shown in Figure 12, the IP filter 18D includes a first alignment film 38a for the shutter, a second alignment film 38b for the shutter positioned opposite the first alignment film 38a for the shutter, and a liquid crystal layer 39 for the shutter, which is filled between the first alignment film 38a and the second alignment film 38b for the shutter in a range that functions as at least a first light-transmitting portion 24F and a second light-transmitting portion 24G. The IP filter 18D also includes a shutter drive unit 40 that can switch the orientation direction of the liquid crystal molecules in the liquid crystal layer 39 on a pixel-by-pixel basis. The shutter drive unit 40 has an upper electrode 40a positioned on the light-receiving side (upper side = polarizing unit 30 side) of the first alignment film 38a for the shutter and a lower electrode 40b positioned on the light-emitting side (lower side) of the second alignment film 38b for the shutter.

[0064] The upper electrode 40a and the lower electrode 40b are formed by creating transparent electrodes 41a and 41b on a transparent substrate, respectively. The transparent electrode 41a of the upper electrode 40a and the transparent electrode 41b of the lower electrode 40b are arranged orthogonally. This allows for selective switching of the voltage on and off (presence or absence of voltage application) for the liquid crystal molecules of the shutter liquid crystal layer 39 at a pixel 19 unit level. Furthermore, the orientation processing direction of the first alignment film 38a for the shutter and the orientation processing direction of the second alignment film 38b for the shutter are orthogonal to each other. Specifically, the alignment groove 42a formed in the first alignment film 38a for the shutter and the alignment groove 42b of the second alignment film 38b for the shutter are arranged orthogonally. In this embodiment, the alignment groove 42a is oriented horizontally and the alignment groove 42b is oriented vertically, but the orientation of the alignment grooves 42a and 42b is not limited to this; it is sufficient that the alignment grooves 42a and 42b are orthogonal to each other.

[0065] Furthermore, as shown in Figure 13, the IP filter 18D has a shielding portion 43 that shields areas other than those that function as the first light-transmitting portion 24F and the second light-transmitting portion 24G of the liquid crystal layer 39 for the shutter. This shielding portion 43 only needs to be able to shield light. For example, through holes can be formed only in the areas that function as the first light-transmitting portion 24F and the second light-transmitting portion 24G of a non-transmitting plate material, and liquid crystal can be filled in these holes. A first alignment film 38a for the shutter and a second alignment film 38b for the shutter can be placed on both sides of the plate, so that areas other than those that function as the first light-transmitting portion 24F and the second light-transmitting portion 24G can function as the shielding portion 43. Alternatively, the entire space sandwiched between the first alignment film 38a and the second alignment film 38b for the shutter can be filled with liquid crystal, and the areas other than those functioning as the first light-transmitting portion 24F and the second light-transmitting portion 24G of the first alignment film 38a and the second alignment film 38b for the shutter can be colored, for example, black to function as a shielding portion 43.

[0066] As shown in Figures 12 and 13, the polarizer 31c is positioned on the light-emitting side of the IP filter 18D. As shown in Figure 12, the polarizer 31c has a polarization axis 44 parallel to the first direction. The polarizer 31c is a conventionally known type and can only allow linearly polarized light in the first direction parallel to the polarization axis 44 to pass through. The spatial image display unit 12D also includes a spacer 45 positioned between the polarization unit 30 and the IP filter 18D, as shown in Figures 12 and 13. The spacer 45 is transparent and light-transmitting, allowing light that has passed through the polarization unit 30 to pass through without reflection, and a synthetic resin with low birefringence is preferably used.

[0067] The operation of the spatial image display unit 12D configured as described above will now be explained. As explained in the second embodiment (see Figure 6), the IP image panel 17A simultaneously displays the first IP image 21A and the second IP image 21B. At this time, as shown in Figure 13, the pixels 19 (solid hatched area) that constitute the element image 15A included in the first IP image 21A and the pixels 19 (dashed hatched area) that constitute the element image 15B included in the second IP image 21B are arranged so as not to overlap each other. Linearly polarized light is emitted from the first IP image 21A and the second IP image 21B in a first direction. The operation of the polarization unit 30 is as explained in the second embodiment, and it can linearly polarize the light emitted from the first IP image 21A in a first direction (more precisely, allow the light linearly polarized in the first direction to pass through as is), and linearly polarize the light emitted from the second IP image 21B in a second direction perpendicular to the first direction.

[0068] Therefore, as shown in Figure 13, the light emitted from the first IP image 21A (solid line) passes through the polarizing unit 30, becomes linearly polarized in the first direction, passes through the spacer 45, and enters the IP filter 18D. The light emitted from the second IP image 21B (dashed line) passes through the polarizing unit 30, becomes linearly polarized in the second direction, passes through the spacer 45, and enters the IP filter 18D. In Figure 12, when the voltage between the upper electrode 40a and the lower electrode 40b of the IP filter 18D is ON (voltage applied), the liquid crystal molecules sandwiched between the first alignment film 38a and the second alignment film 38b for the shutter align upright (along the electric field) so as to be perpendicular to the first alignment film 38a and the second alignment film 38b for the shutter. Thus, light passing through the shutter liquid crystal layer 39, in which the alignment direction of the liquid crystal molecules is perpendicular to the first alignment film 38a and the second alignment film 38b for the shutter, travels in a straight line along the alignment direction of the liquid crystal molecules. Therefore, the direction of linear polarization does not change before and after passing through the shutter liquid crystal layer 39.

[0069] In contrast, when the voltage between the upper electrode 40a and the lower electrode 40b is off (no voltage applied), the liquid crystal molecules of the shutter liquid crystal layer 39 sandwiched between the first shutter alignment film 38a and the second shutter alignment film 38b align along the alignment groove 42a on the first shutter alignment film 38a side and along the alignment groove 42b on the second shutter alignment film 38b side. As a result, when the voltage between the upper electrode 40a and the lower electrode 40b is off (no voltage applied), the alignment direction of the liquid crystal molecules of the shutter liquid crystal layer 39 sandwiched between the first shutter alignment film 38a and the second shutter alignment film 38b is gradually twisted from the first shutter alignment film 38a toward the second shutter alignment film 38b, and is finally twisted by 90 degrees. In this way, light passing through the liquid crystal layer 39 for the shutter, in which the alignment direction of the liquid crystal molecules is twisted by 90 degrees, is twisted by 90 degrees along the alignment direction of the liquid crystal molecules. As a result, the direction of linear polarization changes (rotates) by 90 degrees before and after passing through the liquid crystal layer 39 for the shutter.

[0070] Therefore, in the IP filter 18D of Figure 12, by setting the voltage between the upper electrode 40a and the lower electrode 40b corresponding to the first light-transmitting section 24F to the ON state (voltage applied), the first light-transmitting section 24F can pass through the light emitted from the first IP image 21A and linearly polarized in the first direction by the polarization unit 30 (solid line) and the light emitted from the second IP image 21B and linearly polarized in the second direction by the polarization unit 30 (dashed line), as shown in Figure 13. Furthermore, in the IP filter 18D shown in Figure 12, by setting the voltage between the upper electrode 40a and the lower electrode 40b corresponding to the second light-transmitting section 24G to the OFF state (no voltage applied), the second light-transmitting section 24G can, as shown in Figure 13, allow light (solid line) emitted from the first IP image 21A and linearly polarized in the first direction by the polarizing unit 30 to pass through after being linearly polarized in the second direction, and light (dashed line) emitted from the second IP image 21B and linearly polarized in the second direction by the polarizing unit 30 to pass through after being linearly polarized in the first direction.

[0071] However, since a polarizer 31c is positioned on the light-emitting side of the IP filter 18D that allows only light linearly polarized in the first direction to pass through, of the light passing through the first light-transmitting section 24F, only the light emitted from the first IP image 21A and that has passed through the first light-transmitting section 24F (liquid crystal layer 39 for shutter) while being linearly polarized in the first direction by the polarization unit 30 (solid line) passes through the polarizer 31c and is emitted, while the light emitted from the second IP image 21B and that has passed through the first light-transmitting section 24F (liquid crystal layer 39 for shutter) while being linearly polarized in the second direction by the polarization unit 30 (dashed line) cannot pass through the polarizer 31c. Furthermore, of the light passing through the second light-transmitting section 24G, the light emitted from the first IP image 21A, linearly polarized in the first direction by the polarizing unit 30, and then linearly polarized in the second direction while passing through the second light-transmitting section 24G (solid line) cannot pass through the polarizer 31c. Only the light emitted from the second IP image 21B, linearly polarized in the second direction by the polarizing unit 30, and then linearly polarized in the first direction while passing through the second light-transmitting section 24G (dashed line) passes through the polarizer 31c and is emitted. Of the light that has passed through the polarizing unit 30, the light that irradiates areas other than the first light-transmitting section 24F and the second light-transmitting section 24G of the IP filter 18D and does not contribute to the imaging of a spatial image is shielded by the shielding section 43, and therefore does not leak out to the outside of the IP filter 18D.

[0072] As described above, in the spatial image display 12D, by combining a liquid crystal shutter type IP filter 18D and a polarizer 31c with a polarization direction selectable (switchable) in the polarization unit 30, ultimately, only light emitted from the first IP image 21A is emitted from the first light-transmitting section 24F, and only light emitted from the second IP image 21B is emitted from the second light-transmitting section 24G. Therefore, the spatial image display 12D has the same operation and effect as the spatial image display 12A and the spatial image display 12C. The structure of the shutter drive unit 40 in the IP filter 18D can be appropriately selected and used from a structure similar to that of a conventionally known drive unit in a liquid crystal display. In this embodiment, the transparent electrode 41a is arranged along the column direction (vertically) and the transparent electrode 41b is arranged along the row direction (horizontally), but the arrangement of the transparent electrode 41a and the transparent electrode 41b may be swapped. Furthermore, although a simple matrix drive system image display drive unit was used in this embodiment, an active matrix drive system (TFT) image display drive unit may also be used.

[0073] The present invention has been described above with reference to examples, but the present invention is not limited in any way to the configurations described in the above examples, and includes other embodiments and modifications that can be considered within the scope of the claims. The IP image panel only needs to be able to display the IP image by making each pixel constituting the IP image (element image) emit light. As the IP image panel, for example, a display using liquid crystal, LED or OLED is preferably used, but is not limited to these. The shape of the pixels is not limited to squares, but may also be rectangular. In addition, in the above embodiments 1 to 4, an IP filter with a light-transmitting portion formed on a light-shielding plate was used, but a liquid crystal shutter or PDLC (dimmable film) may be used as the IP filter.

[0074] According to the present invention, a spatial image display system is provided that has a simple structure, does not require complicated control, and can display a spatial image that can be viewed by the observer with the same sense as in everyday life without using special glasses, and is easily scaled up, thereby promoting the widespread adoption and expansion of applications of spatial image display systems.

[0075] 10: Spatial image display system, 11: IP image converter, 12: Spatial image display unit, 12A: Spatial image display unit, 12B: Spatial image display unit, 12C: Spatial image display unit, 12D: Spatial image display unit, 13: Control unit, 14: Spatial image display device, 15: Elemental image, 15A: Elemental image, 15B: Elemental image, 15C: Elemental image, 15D: Elemental image, 15E: Elemental image, 17: IP image panel, 17A: IP image panel, 18: IP filter, 18A: IP filter, 18B: IP filter, 18C: IP filter, 18D: IP filter, 1 9: Pixel, 20: Display surface, 21: IP image, 21A: First IP image, 21B: Second IP image, 21C: IP image, 21D: First IP image, 21E: Second IP image, 23: Light shielding plate, 24: Light-transmitting section, 24A: First light-transmitting section, 24B: Second light-transmitting section, 24C: Light-transmitting section, 24D: First light-transmitting section, 24E: Second light-transmitting section, 24F: First light-transmitting section, 24G: Second light-transmitting section, 25: Partition section, 26: Spatial image display element, 26A: Linear spatial image display element, 27: Unit image display section, 27A: Linear image display section, 28: Unit image light-transmitting Section, 28A: Linear image light-transmitting section, 29: Image display surface, 29A: Image display surface, 30: Polarization unit, 31a: First linear polarizing filter, 31b: Second linear polarizing filter, 31c: Polarizer, 32a: First polarization alignment film, 32b: Second polarization alignment film, 33: Polarizing liquid crystal layer, 34: Polarizing drive section, 34a: Upper electrode, 34b: Lower electrode, 35a: Transparent electrode, 35b: Transparent electrode, 36a: Alignment groove, 36b: Alignment groove, 38a: First alignment film for shutter, 38b: Second alignment film for shutter, 39: Liquid crystal layer for shutter, 40 : Shutter drive unit, 40a: Upper electrode, 40b: Lower electrode, 41a: Transparent electrode, 41b: Transparent electrode, 42a: Alignment groove, 42b: Alignment groove, 43: Shielding part, 44: Polarization axis, 45: Spacer, 50: Three-dimensional object (object), 51: Light-shielding panel, 52a-52c: Pinhole, 53: Photosensitive film, 54-56: Object point, 54a-54c, 55a-55c, 56a-56c: Light ray, 57a-57c, 58a-58c, 59a-59c: Micro-image, 60a-60c: Element image, 60a'-60c': Element image, 61: IP image

Claims

1. A spatial image display system that uses IP technology to display an object as a spatial image, comprising: (a) an IP image converter that converts captured images obtained by photographing the object from multiple viewpoints into a group of elemental images, each consisting of multiple elemental images necessary for displaying the spatial image; and (b) a spatial image display unit that integrates an IP image panel, which displays an IP image composed of multiple elemental images of the group of elemental images on a display surface configured with multiple pixels arranged vertically and horizontally, and an IP filter, which is positioned in front of the display surface of the IP image panel and has one light-transmitting portion at a position corresponding to the center of each of the multiple elemental images on the IP image when viewed from the front.

2. The multiple element images on the IP image are each configured in a rectangular shape with vertical dimension a and horizontal dimension b when viewed from the front, using multiple pixels of the IP image panel, and are arranged vertically and horizontally, and the light-transmitting portion is formed in a pinhole shape with a vertical pitch P ａ = a, lateral pitch P ｂ The elements are arranged vertically and horizontally at =b, and the distance g from the display surface of the IP image panel to the IP filter is the vertical pitch P of the light-transmitting portion. ａ and the lateral pitch P ｂ The spatial image display system according to claim 1, characterized in that it is in the range of 0.5 to 5 times.

3. The multiple element images on the IP image are arranged horizontally, each configured by multiple pixels of the IP image panel to form a rectangle with a horizontal dimension W and a vertical dimension equal to the vertical dimension of the display surface when viewed from the front, and the light-transmitting portion is formed in a vertically elongated slit shape with a horizontal pitch P Ｗ Arranged horizontally in a W shape, the distance g from the display surface of the IP image panel to the IP filter is the horizontal pitch P of the light-transmitting portion. Ｗ The spatial image display system according to claim 1, characterized in that it is in the range of 0.5 to 5 times.

4. The spatial image display system according to claim 1, characterized in that the object is a computer-generated image, and the IP image converter generates the captured image and a plurality of element images by calculation, assuming that the object is virtually photographed by a camera.

5. The spatial image display system according to claim 1, characterized in that the spatial image display device is composed of a plurality of spatial image display elements arranged vertically and horizontally, and each of the plurality of spatial image display elements has a unit image display section obtained by dividing the IP image panel into the element image units on the IP image, and a unit image light transmission section obtained by dividing the IP filter into the element image units on the IP image, and is separated from other adjacent spatial image display elements by a partition section.

6. The spatial image display system according to claim 5, characterized in that the unit image display unit is bent or curved to function as the partition unit.

7. The spatial image display system according to claim 1, characterized in that the spatial image display device is composed of a plurality of linear spatial image display elements arranged in a row or column direction, and each of the plurality of linear spatial image display elements has a linear image display section obtained by dividing the IP image panel into row or column units of the IP image, and a linear image light-transmitting section obtained by dividing the IP filter into row or column units of the IP image, and is separated from other adjacent linear spatial image display elements by a partition.

8. The spatial image display system according to claim 7, characterized in that the line-shaped image display section is bent or curved to function as the partition section.

9. The spatial image display system according to claim 1, comprising a plurality of IP image converters, a plurality of spatial image displays provided one for each of the plurality of IP image converters, and a control unit for controlling the plurality of IP image converters, wherein the plurality of spatial image displays are arranged vertically and horizontally and seamlessly connected to form a spatial image display device.

10. The IP image converter generates a first IP image and a second IP image, each composed of two different sets of elemental images. The IP image panel displays the first IP image and the second IP image simultaneously, such that the pixels constituting each of the multiple elemental images in the first IP image and the pixels constituting each of the multiple elemental images in the second IP image do not overlap. The spatial image display unit (a) is positioned between the IP image panel and the IP filter, and linearly polarizes the light emitted from the first IP image in a first direction, and from the second IP image... The spatial image display system according to claim 1, comprising: (b) a polarization unit that linearly polarizes emitted light in a second direction perpendicular to the first direction; (c) a first linear polarization filter provided corresponding to the light-transmitting portion located at the center of each of the plurality of element images included in the first IP image when viewed from the front, and which allows only light linearly polarized in the first direction to pass through; and (d) a second linear polarization filter provided corresponding to the light-transmitting portion located at the center of each of the plurality of element images included in the second IP image when viewed from the front, and which allows only light linearly polarized in the second direction to pass through.

11. The IP image converter generates a first IP image and a second IP image, each composed of two different groups of elemental images, and the IP image panel displays the first IP image and the second IP image simultaneously such that the pixels constituting each of the multiple elemental images included in the first IP image and the pixels constituting each of the multiple elemental images included in the second IP image do not overlap, and the spatial image display unit comprises (a) a polarization unit disposed between the IP image panel and the IP filter, which linearly polarizes the light emitted from the first IP image in a first direction and the light emitted from the second IP image in a second direction perpendicular to the first direction, and (b) a polarizer disposed on the light-emitting surface side of the IP filter, which has a polarization axis parallel to the first direction. The spatial image display system according to claim 1, wherein the IP filter functions as a first light-transmitting area in a region that overlaps with one or more pixels located at the center of each of the multiple element images included in the first IP image when viewed from the front, allowing light linearly polarized in the first direction by the polarization unit and light linearly polarized in the second direction by the polarization unit to pass through as is; and functions as a second light-transmitting area in a region that overlaps with one or more pixels located at the center of each of the multiple element images included in the second IP image when viewed from the front, allowing light linearly polarized in the first direction by the polarization unit to pass through after being linearly polarized in the second direction, and light linearly polarized in the second direction by the polarization unit to pass through after being linearly polarized in the first direction.

12. The spatial image display system according to claim 10 or 11, characterized in that the polarizing unit comprises a first polarizing alignment film, a second polarizing alignment film disposed opposite to the first polarizing alignment film, a polarizing liquid crystal layer made of liquid crystal filled between the first polarizing alignment film and the second polarizing alignment film, and a polarizing drive unit capable of switching the orientation direction of the liquid crystal molecules in the polarizing liquid crystal layer on a pixel-by-pixel basis, wherein the orientation processing direction of the first polarizing alignment film and the orientation processing direction of the second polarizing alignment film are orthogonal to each other.

13. The spatial image display system according to claim 11, wherein the IP filter comprises a first alignment film for shutters, a second alignment film for shutters disposed opposite to the first alignment film for shutters, a liquid crystal layer for shutters made of liquid crystal filled between the first alignment film for shutters and the second alignment film for shutters in a range that functions as at least the first and second light-transmitting portions, a shutter drive unit capable of switching the orientation direction of the liquid crystal molecules in the liquid crystal layer for shutters on a pixel-by-pixel basis, and a shielding portion that shields areas other than the range that functions as the first and second light-transmitting portions of the liquid crystal layer for shutters, wherein the orientation processing direction of the first alignment film for shutters and the orientation processing direction of the second alignment film for shutters are orthogonal to each other.

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