Aerial video display device

Abstract

To provide a more suitable aerial image display device, which contributes to the Sustainable Development Goals (SDGs) of "3 Good health and well-being", "9 Industry, innovation and infrastructure" and "11 Sustainable cities and communities".SOLUTION: An aerial video display device includes: a display unit; a lenticular lens arranged on a video light emitting surface of the display unit; and an optical system. An angle of field θL of the lenticular lens and a diffusion angle θV of video light emitted from the display unit satisfy θL≥θV, thereby preventing pseudoscopic viewing in a multi-view aerial image.SELECTED DRAWING: Figure 15

Description

Technical Field

[0001] The present invention relates to an airborne floating image display device.

Background Art

[0002] Regarding airborne floating information display technology, for example, it is disclosed in Patent Document 1.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, Patent Document 1 does not fully consider a specific technique for displaying a floating image in space as a three-dimensional shape.

[0005] Therefore, an object of the present invention is to provide an airborne floating image display device that can generate a multi-viewpoint image by a simpler method and display a floating image in space that can be stereoscopically viewed based on the parallax between the user's right eye and left eye. In particular, when displaying a three-dimensional shape based on the above parallax, it is to provide a technique for preventing a phenomenon in which the right-eye image is incident on the user's left eye and the left-eye image is incident on the user's right eye, so-called reverse viewing.

Means for Solving the Problems

[0006] In order to solve the above problems, for example, the configuration described in the claims is adopted. The present invention includes a plurality of means for solving the above problems. If an example is given, it is as follows. An airborne floating image display device that forms an airborne floating image in the air includes a display unit that displays an image of an object, a lenticular lens disposed on the image light emission side of the display unit, and an optical system that generates an airborne floating image based on the image displayed by the display unit. The display unit displays a multi-viewpoint image obtained by photographing or rendering from a plurality of viewpoints as an object. In particular, when displaying the multi-viewpoint image, in order to prevent a phenomenon in which the right-eye image is incident on the user's left eye and the left-eye image is incident on the user's right eye, that is, so-called reverse viewing, the relationship between the viewing angle θL of the lenticular lens and the diffusion angle θV of the image light from the display unit is θL≧θV.

Effect of the Invention

[0007] According to the present invention, a more suitable airborne floating image display device can be realized. Other problems, configurations, and effects will be clarified in the description of the following embodiments.

Brief Description of the Drawings

[0008]

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Mode for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the description of the embodiments, and various changes and modifications can be made by those skilled in the art within the scope of the technical idea disclosed in this specification. Also, in all the drawings for explaining the present invention, those having the same function may be given the same reference numerals, and the repeated description thereof may be omitted.

[0010] The following embodiments relate to a video display device capable of transmitting a video by video light from a video light source through a transparent member that partitions a space such as glass and displaying it as a space-floating video outside the transparent member. In the description of the following embodiments, a video floating in space is expressed by the term "space-floating video". Instead of this term, it may be expressed as "aerial image", "space image", "aerial floating video", "space-floating optical image of the display video", "aerial-floating optical image of the display video", etc. The term "space-floating video" mainly used in the description of the embodiments is used as a representative example of these terms.

[0011] According to the following embodiments, for example, a video display device suitable for use in bank ATMs, station ticket vending machines, digital signage, etc. can be realized. For example, currently, touch panels are usually used in bank ATMs, station ticket vending machines, etc. However, by using a transparent glass surface or a light-transmissive plate material, high-resolution video information can be displayed in a state of being spatially floating on this glass surface or light-transmissive plate material. At this time, by making the divergence angle of the emitted video light small, that is, an acute angle, and further aligning it with a specific polarization, only the regular reflected light is efficiently reflected to the retroreflective plate, so the light utilization efficiency is high, and it is possible to suppress the ghost images that occur in addition to the main spatially floating image, which has been a problem in the conventional retroreflective method, and a clear spatially floating video can be obtained. In addition, with the device including the light source of this embodiment, it is possible to provide a novel and highly usable spatially floating video display device (spatially floating video display system) capable of significantly reducing power consumption. Also, for example, it is possible to provide a vehicle-use spatially floating video display device capable of so-called one-directional spatially floating video display that is visible inside and / or outside the vehicle in a vehicle. <Example 1>

[0012] <An example of the usage form of the spatially floating video display device> FIG. 1 is a diagram showing an example of a usage form of a spatial floating image display device according to an embodiment of the present invention, and is a diagram showing the overall configuration of the spatial floating image display device according to the present embodiment. Regarding the specific configuration of the spatial floating image display device, it will be described in detail with reference to FIG. 2 and the like. Light of a specific polarization with a sandwiching angle directivity characteristic is emitted as an image light beam from the image display device 1, once enters the retroreflective plate 2 after being reflected by the optical system in the spatial floating image display device, is retroreflected, and passes through a transparent member 100 (such as glass), and an aerial image (spatial floating image 3) which is a real image is formed outside the glass surface. In the following embodiments, the retroreflective plate 2 (retroreflective plate) will be described as an example of the retroreflective member. However, the retroreflective plate 2 of the present invention is not limited to a planar plate, and is used as an example of a concept including a sheet-like retroreflective member attached to a planar or non-planar member, or the entire assembly with a sheet-like retroreflective member attached to a planar or non-planar member. Further, since the light beam after reflection by the retroreflective plate 2 has an optical characteristic of forming an image, the retroreflective plate 2 may be expressed as an imaging optical member or an imaging optical plate.

[0013] Also, in a store or the like, a space is partitioned by a show window (also referred to as “window glass”) 105 which is a translucent member such as glass. According to the spatial floating image display device of the present embodiment, it is possible to display a floating image in one direction with respect to the outside and / or the inside of the store (space) through such a transparent member.

[0014] In FIG. 1, the inside (inside the store) of the window glass 105 is shown in the depth direction, and the outside (for example, the sidewalk) is in the foreground. On the other hand, by providing means for reflecting a specific polarization wave on the window glass 105, it is also possible to form an aerial image at a desired position inside the store.

[0015] <Configuration example of the optical system of the spatial floating image display device> FIG. 2A is a diagram showing an example of the configuration of an optical system of a spatial floating image display device according to an embodiment of the present invention. The configuration of the spatial floating image display device will be described more specifically with reference to FIG. 2A. As shown in FIG. 2A(1), a display device 1 that diverges image light of a specific polarization at a sandwiching angle is provided in an oblique direction of a transparent member 100 such as glass. The display device 1 includes a liquid crystal display panel 11 and a light source device 13 that generates light of a specific polarization having a sandwiching angle diffusion characteristic.

[0016] The image light of the specific polarization from the display device 1 is reflected by a polarization separation member 101 having a film that selectively reflects the image light of the specific polarization provided on the transparent member 100 (in the figure, the polarization separation member 101 is formed in a sheet shape and adhered to the transparent member 100), and enters the retroreflector 2. A λ / 4 plate 21 is provided on the image light incident surface of the retroreflector 2. The image light is polarization-converted from a specific polarization to the other polarization by passing through the λ / 4 plate 21 twice, when entering and exiting the retroreflector 2. Here, since the polarization separation member 101 that selectively reflects the image light of the specific polarization has the property of transmitting the polarization of the other polarization that has been polarization-converted, the image light of the specific polarization after polarization conversion passes through the polarization separation member 101. The image light that has passed through the polarization separation member 101 forms a spatial floating image 3, which is a real image, outside the transparent member 100. Note that FIG. 2A shows an example in which the principal ray of the image light incident on the retroreflector 2 is incident on the retroreflector 2 at 90°. However, the incident angle of the principal ray of the image light with respect to the retroreflector 2 is not limited to 90°, and for example, an angle of 90° ± 15° can also be used.

[0017] Here, a first example of the polarization design in the optical system of FIG. 2A will be described. For example, the configuration may be such that S-polarized video light is emitted from the display device 1 to the polarization separation member 101, and the polarization separation member 101 has the property of reflecting S-polarized light and transmitting P-polarized light. In this case, the S-polarized video light that has reached the polarization separation member 101 from the display device 1 is reflected by the polarization separation member 101 and travels toward the retroreflector 2. When the video light is reflected by the retroreflector 2, since it passes through the λ / 4 plate 21 provided on the incident surface of the retroreflector 2 twice, the video light is converted from S-polarized light to P-polarized light. The video light converted to P-polarized light travels toward the polarization separation member 101 again. Here, since the polarization separation member 101 has the property of reflecting S-polarized light and transmitting P-polarized light, the P-polarized video light passes through the polarization separation member 101 and then through the transparent member 100. Since the video light that has passed through the transparent member 100 is the light generated by the retroreflector 2, a spatial floating image 3, which is an optical image of the display image of the display device 1, is formed at a position that has a mirror image relationship with the display image of the display device 1 with respect to the polarization separation member 101. Such a polarization design can preferably form the spatial floating image 3.

[0018] Next, a second example of the polarization design in the optical system of FIG. 2A will be described. For example, the configuration may be such that P-polarized video light is emitted from the display device 1 to the polarization separation member 101, and the polarization separation member 101 has the property of reflecting P-polarization and transmitting S-polarization. In this case, the P-polarized video light that has reached the polarization separation member 101 from the display device 1 is reflected by the polarization separation member 101 and travels toward the retroreflector 2. When the video light is reflected by the retroreflector 2, since it passes through the λ / 4 plate 21 provided on the incident surface of the retroreflector 2 twice, the video light is converted from P-polarization to S-polarization. The video light converted to S-polarization travels toward the polarization separation member 101 again. Here, since the polarization separation member 101 has the property of reflecting P-polarization and transmitting S-polarization, the S-polarized video light passes through the polarization separation member 101 and then through the transparent member 100. Since the video light that has passed through the transparent member 100 is the light generated by the retroreflector 2, a spatial floating image 3, which is an optical image of the display image of the display device 1, is formed at a position that has a mirror relationship with the display image of the display device 1 with respect to the polarization separation member 101. Such a polarization design can preferably form the spatial floating image 3.

[0019] Note that the light forming the spatial floating image 3 is a collection of light rays that converge from the retroreflector 2 to the optical image of the spatial floating image 3, and these light rays continue to travel straight even after passing through the optical image of the spatial floating image 3. Therefore, unlike the diffused video light formed on a screen by a general projector or the like, the spatial floating image 3 is an image with high directivity. Thus, in the configuration of FIG. 2A, when viewed by the user from the direction of arrow A, the spatial floating image 3 is viewed as a bright image. However, when viewed by another person from the direction of arrow B, the spatial floating image 3 cannot be viewed as an image at all. This characteristic is very suitable for use in a system that displays an image that requires high security or an image with high confidentiality that needs to be concealed from a person facing the user.

[0020] Depending on the performance of the retroreflector 2, the polarization axes of the image light after reflection may be misaligned. Also, the reflection angles may be misaligned. Such non-uniform light may not maintain the polarization state and propagation angle assumed in the design. For example, light with a polarization state and propagation angle outside the design assumption may directly re-enter the image display surface side of the liquid crystal display panel 11 from the position of the retroreflector 2 without passing through the polarization separation member. Light with a polarization state and propagation angle outside the design assumption may also re-enter the image display surface side of the liquid crystal display panel 11 after being reflected by components within the spatial floating image display device. The light that re-enters the image display surface side of such a liquid crystal display panel 11 may be re-reflected by the image display surface of the liquid crystal display panel 11 constituting the display device 1, generating a ghost image and potentially degrading the image quality of the spatial floating image. Therefore, in this embodiment, an absorption-type polarizing plate 12 may be provided on the image display surface of the display device 1. The image light emitted from the display device 1 is transmitted through the absorption-type polarizing plate 12, and the reflected light returning from the polarization separation member 101 is absorbed by the absorption-type polarizing plate 12, thereby suppressing the above-mentioned re-reflection. As a result, it is possible to prevent degradation of the image quality due to the ghost image of the spatial floating image. Specifically, if the configuration is such that S-polarized image light is emitted from the display device 1 to the polarization separation member 101, the absorption-type polarizing plate 12 may be a polarizing plate that absorbs P-polarization. Also, if the configuration is such that P-polarized image light is emitted from the display device 1 to the polarization separation member 101, the absorption-type polarizing plate 12 may be a polarizing plate that absorbs S-polarization.

[0021] The above-described polarization separation member 101 may be formed, for example, of a reflective polarizing plate or a metal multilayer film that reflects a specific polarization wave.

[0022] Next, FIG. 2A(2) shows an example of the surface shape of a representative retroreflector 2 as the retroreflector. Light rays incident inside regularly arranged hexagonal prisms are reflected by the wall surfaces and bottom surfaces of the hexagonal prisms and are emitted as retroreflected light in a direction corresponding to the incident light, displaying a spatial floating image that is a real image based on the image displayed on the display device 1.

[0023] The resolution of this floating image in space depends greatly on the outer shape D and pitch P of the retroreflective portion of the retroreflector 2 shown in Fig. 2A(2), in addition to the resolution of the liquid crystal display panel 11. For example, when using a 7-inch WUXGA (1920×1200 pixels) liquid crystal display panel, even if one pixel (one triplet) is about 80 μm, if the diameter D of the retroreflective portion is 240 μm and the pitch is 300 μm, for example, one pixel of the floating image in space is equivalent to 300 μm. Therefore, the effective resolution of the floating video is reduced to about one-third.

[0024] Therefore, in order to make the resolution of the floating video in space equivalent to the resolution of the display device 1, it is desirable to make the diameter and pitch of the retroreflective portion closer to one pixel of the liquid crystal display panel. On the other hand, in order to suppress the occurrence of moiré due to the pixels of the retroreflector and the liquid crystal display panel, it is advisable to design by deviating the respective pitch ratios from an integer multiple of one pixel. Also, the shape should be arranged so that none of the sides of the retroreflective portion overlap any of the sides of one pixel of the liquid crystal display panel.

[0025] Note that the surface shape of the retroreflector according to this embodiment is not limited to the above example. It may have various surface shapes that realize retroreflectivity. Specifically, a retroreflective element in which triangular pyramid prisms, hexagonal pyramid prisms, other polygonal prisms, or combinations thereof are periodically arranged may be provided on the surface of the retroreflector of this embodiment. Or, a retroreflective element that forms a cube corner by periodically arranging these prisms may be provided on the surface of the retroreflector of this embodiment. These can also be expressed as a corner reflector array or a polyhedral reflector array. Or, a capsule lens type retroreflective element in which glass beads are periodically arranged may be provided on the surface of the retroreflector of this embodiment. Since the detailed configuration of these retroreflective elements may use existing technologies, detailed description is omitted. Specifically, the technologies disclosed in Japanese Patent Application Laid-Open No. 2001-33609, Japanese Patent Application Laid-Open No. 2001-264525, Japanese Patent Application Laid-Open No. 2005-181555, Japanese Patent Application Laid-Open No. 2008-70898, Japanese Patent Application Laid-Open No. 2009-229942, etc. may be used.

[0026] <Another Configuration Example 1 of the Optical System of the Spatial Floating Image Display Device> Another configuration example of the optical system of the spatial floating image display device will be described with reference to Fig. 2B. In Fig. 2B, components labeled with the same reference numerals as in Fig. 2A have the same functions and configurations as those in Fig. 2A. For such components, repetitive descriptions will be omitted for the sake of simplicity.

[0027] In the optical system of Fig. 2B, similar to Fig. 2A, image light of a specific polarization is output from the display device 1. The image light of the specific polarization output from the display device 1 is input to the polarization separation member 101B. The polarization separation member 101B is a member that selectively transmits the image light of the specific polarization. Different from the polarization separation member 101 in Fig. 2A, the polarization separation member 101B is not integrated with the transparent member 100 and has an independent plate-like shape. Therefore, the polarization separation member 101B may be referred to as a polarization separation plate. The polarization separation member 101B may be configured, for example, as a reflective polarizing plate formed by attaching a polarization separation sheet to a transparent member. Alternatively, it may be formed of a metal multilayer film or the like that selectively transmits a specific polarization of the transparent member and reflects the polarization of other specific polarizations. In Fig. 2B, the polarization separation member 101B is configured to transmit the image light of the specific polarization output from the display device 1.

[0028] The image light that has passed through the polarization separation member 101B is incident on the retroreflective plate 2. A λ / 4 plate 21 is provided on the image light incident surface of the retroreflective plate. The image light is polarization-converted from a specific polarization to the other polarization by passing through the λ / 4 plate 21 twice, once when entering the retroreflective plate and once when exiting. Here, since the polarization separation member 101B has the property of reflecting the polarization of the other polarization that has been polarization-converted by the λ / 4 plate 21, the image light after polarization conversion is reflected by the polarization separation member 101B. The image light reflected by the polarization separation member 101B passes through the transparent member 100 and forms a spatial floating image 3, which is a real image, outside the transparent member 100.

[0029] Here, a first example of the polarization design in the optical system of FIG. 2B will be described. For example, it may be configured such that P-polarized video light is emitted from the display device 1 to the polarization separation member 101B, and the polarization separation member 101B has the property of reflecting S-polarized light and transmitting P-polarized light. In this case, the P-polarized video light that has reached the polarization separation member 101B from the display device 1 passes through the polarization separation member 101B and travels toward the retroreflector 2. When the video light is reflected by the retroreflector 2, since it passes through the λ / 4 plate 21 provided on the incident surface of the retroreflector 2 twice, the video light is converted from P-polarized light to S-polarized light. The video light converted to S-polarized light travels toward the polarization separation member 101B again. Here, since the polarization separation member 101B has the property of reflecting S-polarized light and transmitting P-polarized light, the S-polarized video light is reflected by the polarization separation member 101 and passes through the transparent member 100. Since the video light that has passed through the transparent member 100 is the light generated by the retroreflector 2, a spatial floating image 3, which is an optical image of the display image of the display device 1, is formed at a position that has a mirror relationship with the display image of the display device 1 with respect to the polarization separation member 101B. Such a polarization design can preferably form the spatial floating image 3.

[0030] Next, a second example of the polarization design in the optical system of FIG. 2B will be described. For example, the configuration may be such that the S-polarized video light is emitted from the display device 1 to the polarization separation member 101B, and the polarization separation member 101B has the property of reflecting P-polarized light and transmitting S-polarized light. In this case, the S-polarized video light that has reached the polarization separation member 101B from the display device 1 passes through the polarization separation member 101B and travels toward the retroreflector 2. When the video light is reflected by the retroreflector 2, since it passes through the λ / 4 plate 21 provided on the incident surface of the retroreflector 2 twice, the video light is converted from S-polarized light to P-polarized light. The video light converted to P-polarized light travels again toward the polarization separation member 101B. Here, since the polarization separation member 101B has the property of reflecting P-polarized light and transmitting S-polarized light, the P-polarized video light is reflected by the polarization separation member 101 and passes through the transparent member 100. Since the video light that has passed through the transparent member 100 is the light generated by the retroreflector 2, a spatial floating image 3, which is an optical image of the display image of the display device 1, is formed at a position that is in a mirror image relationship with the display image of the display device 1 with respect to the polarization separation member 101B. With such a polarization design, the spatial floating image 3 can be preferably formed.

[0031] In FIG. 2B, the video display surface of the display device 1 and the surface of the retroreflective plate 2 are arranged in parallel. The polarization separation member 101B is arranged at an angle α (for example, 30°) with respect to the video display surface of the display device 1 and the surface of the retroreflective plate 2. Then, in the reflection of the polarization separation member 101B, the traveling direction of the video light reflected by the polarization separation member 101B (the direction of the principal ray of the video light) is different from the traveling direction of the video light incident from the retroreflective plate 2 (the direction of the principal ray of the video light) by an angle β (for example, 60°). By configuring in this way, in the optical system of FIG. 2B, the video light is output at a predetermined angle shown toward the outside of the transparent member 100, and the spatial floating image 3 which is a real image is formed. In the configuration of FIG. 2B, when the user views from the direction of arrow A, the spatial floating image 3 is viewed as a bright image. However, when another person views from the direction of arrow B, the spatial floating image 3 cannot be viewed as an image at all. This characteristic is very suitable when adopted in a system for displaying an image that requires high security or an image with high confidentiality that needs to be concealed from a person facing the user.

[0032] As described above, in the optical system of FIG. 2B, although it is an optical system with a configuration different from that of the optical system of FIG. 2A, it is possible to form a suitable spatial floating image in the same manner as the optical system of FIG. 2A.

[0033] Note that an absorption type polarizing plate may be provided on the surface of the transparent member 100 on the side of the polarization separation member 101B. The absorption type polarizing plate may be an absorption type polarizing plate that transmits the polarization wave of the video light from the polarization separation member 101B and absorbs the polarization wave whose phase is different by 90° from the polarization wave of the video light from the polarization separation member 101B. In this way, while allowing sufficient transmission of the video light for forming the spatial floating image 3, it is possible to reduce the external light incident from the side of the spatial floating image 3 of the transparent member 100 by about 50%. Thereby, it is possible to reduce the stray light in the optical system of FIG. 2B based on the external light incident from the side of the spatial floating image 3 of the transparent member 100.

[0034] <Another configuration example 2 of the optical system of the spatial floating image display device> Another configuration example of the optical system of the spatial floating image display device will be described with reference to FIG. 2C. In FIG. 2C, components denoted by the same reference numerals as in FIG. 2B have the same functions and configurations as those in FIG. 2B. For such components, repeated descriptions will be omitted for the sake of simplicity.

[0035] The difference between the optical system of FIG. 2C and the optical system of FIG. 2B is only the arrangement angle of the polarization separation member 101B with respect to the image display surface of the display device 1 and the surface of the retroreflector 2. Since all other configurations are the same as those of the optical system of FIG. 2B, repeated descriptions will be omitted. Since the polarization design of the optical system of FIG. 2C is the same as that of the optical system of FIG. 2B, repeated descriptions will be omitted.

[0036] In the optical system of FIG. 2C, the polarization separation member 101B is arranged at an angle α with respect to the image display surface of the display device 1 and the surface of the retroreflector 2. In FIG. 2C, the angle α is 45°. With such a configuration, in the reflection of the polarization separation member 101B, the angle β formed by the traveling direction of the image light reflected by the polarization separation member 101B (the direction of the principal ray of the image light) with respect to the traveling direction of the image light incident from the retroreflector 2 (the direction of the principal ray of the image light) is 90°. With such a configuration, the image display surface of the display device 1 and the surface of the retroreflector 2 and the traveling direction of the image light reflected by the polarization separation member 101B are in a right-angle relationship, and the angular relationship of the surfaces constituting the optical system can be simplified. If the surface of the transparent member 100 is arranged to be orthogonal to the traveling direction of the image light reflected by the polarization separation member 101B, the angular relationship of the surfaces constituting the optical system can be further simplified. In the configuration of FIG. 2C, when viewed by the user from the direction of arrow A, the spatial floating image 3 is viewed as a bright image. However, when viewed by another person from the direction of arrow B, the spatial floating image 3 cannot be viewed as an image at all. This characteristic is very suitable for use in a system that displays images that require high security or highly confidential images that need to be concealed from people facing the user.

[0037] As described above, in the optical system of FIG. 2C, although it is an optical system with a configuration different from the optical systems of FIGS. 2A and 2B, it is possible to form a suitable aerial image in the same manner as the optical systems of FIGS. 2A and 2B. Further, the angles of the surfaces constituting the optical system can be made simpler.

[0038] Note that an absorption type polarizing plate may be provided on the surface of the transparent member 100 on the side of the polarization separation member 101B. The absorption type polarizing plate may be an absorption type polarizing plate that transmits the polarization wave of the video light from the polarization separation member 101B and absorbs the polarization wave having a phase difference of 90° from the polarization wave of the video light from the polarization separation member 101B. In this way, while allowing sufficient transmission of the video light for forming the aerial image 3, it is possible to reduce the external light incident from the side of the aerial image 3 of the transparent member 100 by about 50%. Thereby, it is possible to reduce stray light in the optical system of FIG. 2C based on the external light incident from the side of the aerial image 3 of the transparent member 100.

[0039] <Another Configuration Example 3 of the Optical System of the Aerial Image Display Device> Another configuration example of the optical system of the aerial image display device will be described with reference to FIG. 2D. The optical system of FIG. 2D is an optical system using a retroreflector 5, which is different from the retroreflector 2 used in FIGS. 2A to 2C. Hereinafter, with reference to FIGS. 2D to 2I, another configuration example 3 of the optical system will be described more specifically. In FIG. 2D, the components denoted by the same reference numerals as in FIGS. 2A to 2C have the same functions and configurations as in FIGS. 2A to 2C. For such components, repeated description will not be given in order to simplify the explanation.

[0040] FIG. 2D is a diagram showing an example of the main configuration and the retroreflective portion configuration of an aerial image display device according to an embodiment of the present invention. In an oblique direction of a transparent member 100 such as glass, a display device 10 that emits video light is provided. The display device 10 includes a liquid crystal display panel 11 and a light source device 13 that generates light.

[0041] The chief ray 9020, which represents the light beam emitted from the display device 10, travels toward the retroreflector 5 and is incident on the retroreflector 5 at an incident angle α. The incident angle α may be, for example, 45°. However, the incident angle α is not limited to 45°, and it can also be used, for example, at 45° ± 15°.

[0042] The retroreflector 5 is an optical member having the optical property of retroreflecting at least part of the light rays in some directions. Also, since the reflected light rays have the optical property of forming an image, the retroreflector 5 may be referred to as an imaging optical member or an imaging optical plate.

[0043] Regarding the specific configuration of the retroreflector 5, it will be described in detail using FIGS. 2E, 2F, etc. By the retroreflector 5, the chief ray 9020 is retroreflectively reflected in the x and y directions while traveling in the z direction. As a result, the reflected ray 9021 travels in a direction away from the retroreflector 5 along an optical path that is mirror-symmetrical with respect to the chief ray 9020 with respect to the retroreflector 5, passes through the transparent member 100, and forms a spatial floating image 3 as a real image on the imaging surface.

[0044] The light beam forming the spatial floating image 3 is a set of light rays converging from the retroreflector 5 to the optical image of the spatial floating image 3, and these light rays continue to travel straight even after passing through the optical image of the spatial floating image 3. Therefore, the spatial floating image 3 is an image with high directivity, different from the diffused image formed on a screen by a general projector or the like. Thus, in the configuration of FIG. 2, when viewed by the user from the direction of arrow A, the spatial floating image 3 is viewed as a bright image. However, when viewed by another person from the direction of arrow B, the spatial floating image 3 cannot be viewed as an image at all. This characteristic is suitable for use in a system that displays an image requiring high security or an image with high secrecy that needs to be concealed from a person facing the user.

[0045] An example of the configuration of the retroreflector 5 will be described with reference to FIGS. 2E and 2F. The retroreflector 5 has a configuration in which a plurality of corner reflectors 9040 are arranged in an array on the surface of a transparent member 50. This may be referred to as a corner reflector array or a polyhedral reflector array. The specific configuration of the corner reflector 9040 will be described in detail with reference to FIGS. 2G, 2H, and 2I. The light rays 9111, 9112, 9113, and 9114 emitted from the light source 9110 are reflected twice by two mirror surfaces 9041 and 9042 of the corner reflector 9040 to become reflected light rays 9121, 9122, 9123, and 9124. This double reflection results in a retroreflective reflection that folds back in the same direction as the incident direction (advances in the direction rotated by 180°) with respect to the x and y directions, and a specular reflection in which the incident angle and the reflection angle coincide due to total reflection with respect to the z direction.

[0046] That is, the light rays 9111 to 9114 generate the reflected light rays 9121 to 9124 on a straight line symmetric with respect to the z direction with respect to the corner reflector 9040, and form a virtual image 9120 in the air. The light rays 9111 to 9114 emitted from the light source 9110 are four light rays representing the diffused light from the light source 9110. Depending on the diffusion characteristics of the light source 9110, the light rays incident on the retroreflector 5 are not limited to these, but any incident light ray causes a similar reflection and forms a virtual image 9120 in the air. For ease of viewing the drawing, the positions of the light source 9110 and the virtual image 9120 in the x direction are shifted in the drawing, but actually, the positions of the light source 9110 and the virtual image 9120 in the x direction are the same, and they overlap when viewed from the z direction.

[0047] Next, the configuration and effect of the corner reflector 9040 that constitutes the retroreflector 5 will be described with reference to FIGS. 2G, 2H, and 2I. The corner reflector 9040 is a rectangular parallelepiped in which only two specific surfaces are mirror surfaces 9041 and 9042, and the other four surfaces are formed of a transparent member. The retroreflector 5 has a configuration in which the corner reflectors 9040 are arranged in an array such that their corresponding mirror surfaces face the same direction.

[0048] When viewed from above (+z direction), the light ray 9111 emitted from the light source 9110 is incident on the mirror surface 9041 (or mirror surface 9042) at a specific incident angle, and after total reflection at the reflection point 9130, it is totally reflected again at the reflection point 9132 on the mirror surface 9042 (or mirror surface 9041).

[0049] If the incident angle of the light ray 9111 with respect to the mirror surface 9041 (or mirror surface 9042) is θ, the incident angle of the first reflected light ray 9131 reflected by the mirror surface 9041 (or mirror surface 9042) with respect to the mirror surface 9042 (or mirror surface 9041) can be expressed as 90° - θ. Therefore, with respect to the light ray 9111, the second reflected light ray 9121 obtains a rotation of 2θ by the first reflection and 2×(90° - θ) by the second reflection, resulting in a total reverse optical path of 180°. On the other hand, when viewed from the side (the intermediate direction between -x and -y), total reflection with respect to the z direction occurs only once. Therefore, if the incident angle with respect to the mirror surface 9041 or mirror surface 9042 is φ, with respect to the light ray 9111, the reflected light ray 9121 obtains a rotation of 2×φ by one reflection.

[0050] From the above, the light rays incident on the corner reflector 9040 produce a recursive reflection with a reverse optical path in the x and y directions, and a regular reflection by total reflection in the z direction. Considering the recursive reflection plate 5, similar reflections are caused in each optical path, so that in the x and y directions, an inverted optical path with convergence forms an image at a point symmetric with respect to the z-axis direction.

[0051] Here, in the optical systems of FIGS. 2A to 2C, the recursive reflection plate 2 has recursive reflection characteristics in three axial directions. Thereby, when a diffusive incident light beam is incident on the recursive reflection plate 2, a convergent reflected light beam travels toward the side where the light source of the incident light ray exists with respect to the recursive reflection plate 2. The main light ray of the convergent reflected light beam reflected from the recursive reflection plate 2 is in the reverse direction of the main light ray of the diffusive incident light beam incident on the recursive reflection plate 2.

[0052] In contrast, in the optical system of Fig. 2D, the retroreflector 5 has retroreflective characteristics in the biaxial direction and specularly reflects in the other uniaxial direction. Thus, when a diffusive incident light beam is incident on the retroreflector 5, the convergent reflected light beam reflected by the corner reflector array travels toward the side opposite to the side where the light source of the incident light ray exists with respect to the retroreflector 5. The convergent reflected light beam forms a spatial floating image 3 by imaging in the air.

[0053] The traveling direction of the principal ray of the convergent reflected light beam reflected by the corner reflector array of the retroreflector 5 does not become the reverse direction of the traveling direction of the principal ray of the diffusive incident light beam incident on the retroreflector 5. The normal direction component of the plate-shaped surface of the retroreflector 5 with respect to the traveling direction of the principal ray of the diffusive incident light beam incident on the retroreflector 5 and the normal direction component of the plate-shaped surface of the retroreflector 5 with respect to the traveling direction of the principal ray after the reflected light beam becomes convergent after being reflected by the retroreflector 5 travel straight without changing before and after reflection by the corner reflector array.

[0054] That is, due to the reflection in the retroreflector 5, the diffusive incident light beam is converted into a convergent reflected light beam, but in the normal direction of the plate-shaped surface of the retroreflector 5, the light beam travels through the retroreflector 5. Here, the diffusive incident light beam incident on the retroreflector 5 and the convergent reflected light beam emitted from the retroreflector 5 are geometrically plane-symmetric with respect to the plate-shaped surface of the retroreflector 5.

[0055] The resolution of the spatial floating image formed by the light rays from the video output unit 10 depends greatly on the diameter D and pitch P (not shown) of the retroreflective portion of the retroreflector 5 shown in Figs. 2E and 2F in addition to the resolution of the liquid crystal display panel 11. For example, when using a 7-inch WUXGA (1920×1200 pixels) liquid crystal display panel, even if one pixel (one triplet) is about 80 μm, if the diameter D of the retroreflective portion is 240 μm and the pitch P is 300 μm, for example, one pixel of the spatial floating image corresponds to 300 μm. Therefore, the effective resolution of the spatial floating video is reduced to about 1 / 3.

[0056] Therefore, in order to make the resolution of the floating image in space equivalent to that of the display device 10, it is desirable to make the diameter D and the pitch P of the retroreflective portion approach one pixel of the liquid crystal display panel. On the other hand, in order to suppress the occurrence of moiré due to the retroreflective plate and the pixels of the liquid crystal display panel, it is advisable to design by deviating the respective pitch ratios from an integral multiple of one pixel. Also, the shape should be arranged so that none of the sides of the retroreflective portion overlap any of the sides of one pixel of the liquid crystal display panel.

[0057] Note that the shape of the retroreflective plate (imaging optical plate) according to this embodiment is not limited to the above example. It may have various shapes that realize retroreflective properties. Specifically, various cubic corner bodies, corner reflector arrays may be used, or a slit mirror array, a two-sided corner reflector array, a multi-sided reflector array, or a shape in which combinations of its reflective surfaces are periodically arranged may be used. Alternatively, a capsule lens type retroreflective element in which glass beads are periodically arranged may be provided on the surface of the retroreflective plate of this embodiment. Since the detailed configuration of these retroreflective elements may use existing technologies, detailed description is omitted. Specifically, the technologies disclosed in JP-A-2017-33005, JP-A-2019-133110, JP-A-2017-67933, WO2009 / 131128, etc. may be used.

[0058] Note that in the optical system of Fig. 2D, the video light emitted from the display device 10 may be in any polarization state. There is no problem whether it is S-polarized light or P-polarized light.

[0059] As described above, in the optical system of Fig. 2D, although it is an optical system using a retroreflective plate different from the optical systems of Figs. 2A to 2C, a more suitable floating image in space can be formed in the same manner as the optical systems of Figs. 2A to 2C.

[0060] According to the optical systems of Figs. 2A, 2B, 2C, and 2D described above, a brighter and higher-quality floating image in space can be provided.

[0061] <<Block Diagram of the Internal Configuration of the Spatial Floating Image Display Device>>

[0062] Next, a block diagram of the internal configuration of the spatial floating image display device 1000 will be described. FIG. 3 is a block diagram showing an example of the internal configuration of the spatial floating image display device 1000.

[0063] The spatial floating image display device 1000 includes a retroreflective portion 1101, an image display portion 1102, a light guide 1104, a light source 1105, a power supply 1106, an external power input interface 1111, an operation input portion 1107, a nonvolatile memory 1108, a memory 1109, a control portion 1110, an image signal input portion 1131, an audio signal input portion 1133, a communication portion 1132, an air operation detection sensor 1351, an air operation detection portion 1350, an audio output portion 1140, a microphone 1139, an image control portion 1160, a storage portion 1170, an imaging portion 1180, etc. Note that a removable media interface 1134, an attitude sensor 1113, a transmissive self-luminous image display device 1650, a second display device 1680, or a secondary battery 1112, etc. may be provided.

[0064] Each component of the spatial floating image display device 1000 is arranged in a housing 1190. Note that the imaging portion 1180 and the air operation detection sensor 1351 shown in FIG. 3 may be provided outside the housing 1190.

[0065] The retroreflective portion 1101 in FIG. 3 corresponds to the retroreflective plate 2 in FIGS. 2A, 2B, and 2C. The retroreflective portion 1101 retroreflects the light modulated by the image display portion 1102. Among the reflected light from the retroreflective portion 1101, the spatial floating image 3 is formed by the light output to the outside of the spatial floating image display device 1000.

[0066] The image display portion 1102 in FIG. 3 corresponds to the liquid crystal display panel 11 in FIGS. 2A, 2B, and 2C. The light source 1105 in FIG. 3 corresponds to the light source device 13 in FIGS. 2A, 2B, and 2C. And the image display portion 1102, the light guide 1104, and the light source 1105 in FIG. 3 correspond to the display device 1 in FIGS. 2A, 2B, and 2C.

[0067] The video display unit 1102 is a display unit that modulates the transmitted light to generate a video based on the input video signal under the control of the video control unit 1160 described later. The video display unit 1102 corresponds to the liquid crystal display panel 11 in FIGS. 2A, 2B, and 2C. As the video display unit 1102, for example, a transmissive liquid crystal panel is used. Also, as the video display unit 1102, for example, a reflective liquid crystal panel or a DMD (Digital Micromirror Device: registered trademark) panel that modulates reflected light may be used.

[0068] The light source 1105 generates light for the video display unit 1102 and is a solid light source such as an LED light source or a laser light source. The power supply 1106 converts the AC current input from the outside through the external power supply input interface 1111 into a DC current and supplies power to the light source 1105. Also, the power supply 1106 supplies the necessary DC current to each part within the spatial floating video display device 1000. The secondary battery 1112 stores the power supplied from the power supply 1106. Also, when no power is supplied from the outside through the external power supply input interface 1111, the secondary battery 1112 supplies power to the light source 1105 and other components that require power. That is, when the spatial floating video display device 1000 is equipped with the secondary battery 1112, the user can use the spatial floating video display device 1000 even when no power is supplied from the outside.

[0069] The light guide 1104 guides the light generated by the light source 1105 and irradiates the video display unit 1102. The combination of the light guide 1104 and the light source 1105 can also be referred to as the backlight of the video display unit 1102. The light guide 1104 may mainly be configured using glass. The light guide 1104 may mainly be configured using plastic. The light guide 1104 may be configured using a mirror. Various methods are conceivable for the combination of the light guide 1104 and the light source 1105. Specific configuration examples of the combination of the light guide 1104 and the light source 1105 will be described in detail later.

[0070] The air operation detection sensor 1351 is a sensor that detects the operation of the spatially floating image 3 by the finger of the user 230. The air operation detection sensor 1351 senses, for example, a range that overlaps with the entire display range of the spatially floating image 3. Note that the air operation detection sensor 1351 may sense only a range that overlaps with at least a part of the display range of the spatially floating image 3.

[0071] Specific examples of the air operation detection sensor 1351 include distance sensors using non-visible light such as infrared rays, non-visible light lasers, ultrasonic waves, etc. Further, the air operation detection sensor 1351 may be configured by combining a plurality of sensors in a plurality of ways so as to be able to detect two-dimensional plane coordinates. Further, the air operation detection sensor 1351 may be configured by a ToF (Time of Flight) type LiDAR (Light Detection and Ranging) or an image sensor.

[0072] The air operation detection sensor 1351 only needs to be able to sense, for example, a touch operation by the user's finger on the object displayed as the spatially floating image 3. Such sensing can be performed using existing technologies.

[0073] The air operation detection unit 1350 acquires a sensing signal from the air operation detection sensor 1351, and based on the sensing signal, determines the presence or absence of contact of the object of the spatially floating image 3 by the finger of the user 230, and calculates the position (contact position) where the finger of the user 230 contacts the object, etc. The air operation detection unit 1350 is configured by a circuit such as an FPGA (Field Programmable Gate Array), for example. Further, some functions of the air operation detection unit 1350 may be realized by software by a space operation detection program executed by the control unit 1110, for example.

[0074] The air operation detection sensor 1351 and the air operation detection unit 1350 may be incorporated into the spatial floating image display device 1000, or may be provided externally as a separate unit from the spatial floating image display device 1000. When provided as a separate unit from the spatial floating image display device 1000, the air operation detection sensor 1351 and the air operation detection unit 1350 are configured to be able to transmit information and signals to the spatial floating image display device 1000 via a wired or wireless communication connection path or a video signal transmission path.

[0075] Also, the air operation detection sensor 1351 and the air operation detection unit 1350 may be provided as separate units. Thereby, it is possible to construct a system in which a spatial floating image display device 1000 without an air operation detection function is used as the main body and only the air operation detection function can be added as an option. Further, only the air operation detection sensor 1351 may be a separate unit, and the air operation detection unit 1350 may be incorporated into the spatial floating image display device 1000. When it is desired to arrange the air operation detection sensor 1351 more freely with respect to the installation position of the spatial floating image display device 1000, etc., there is an advantage in a configuration in which only the air operation detection sensor 1351 is a separate unit.

[0076] The imaging unit 1180 is a camera having an image sensor, and images the space near the spatial floating image 3 and / or the face, arm, finger, etc. of the user 230. A plurality of imaging units 1180 may be provided. By using a plurality of imaging units 1180 or by using an imaging unit with a depth sensor, the air operation detection unit 1350 can be assisted during the detection process of the touch operation of the spatial floating image 3 by the user 230. The imaging unit 1180 may be provided as a separate unit from the spatial floating image display device 1000. When the imaging unit 1180 is provided as a separate unit from the spatial floating image display device 1000, it may be configured to be able to transmit an imaging signal to the spatial floating image display device 1000 via a wired or wireless communication connection path or the like.

[0077] For example, when the air operation detection sensor 1351 is configured as an object intrusion sensor that detects the presence or absence of an object entering a plane (intrusion detection plane) including the display surface of the floating image 3 in space, the air operation detection sensor 1351 may not be able to detect information such as how far an object (e.g., a user's finger) that has not entered the intrusion detection plane is from the intrusion detection plane, or how close the object is to the intrusion detection plane.

[0078] In such a case, by using information such as the depth calculation information of the object based on the captured images of the plurality of imaging units 1180 and the depth information of the object by the depth sensor, the distance between the object and the intrusion detection plane can be calculated. Then, these information and various information such as the distance between the object and the intrusion detection plane are used for various display controls for the floating image 3 in space.

[0079] Alternatively, without using the air operation detection sensor 1351, the air operation detection unit 1350 may detect a touch operation of the floating image 3 in space by the user 230 based on the captured image of the imaging unit 1180.

[0080] Further, the imaging unit 1180 may image the face of the user 230 who operates the floating image 3 in space, and the control unit 1110 may perform identification processing of the user 230. In addition, in order to determine whether there is someone standing around or behind the user 230 who operates the floating image 3 in space and whether the person is peeping at the operation of the user 230 on the floating image 3, the imaging unit 1180 may image a range including the user 230 who operates the floating image 3 in space and the peripheral area of the user 230.

[0081] The operation input unit 1107 is, for example, an operation button, a signal reception unit such as a remote controller, or an infrared light receiving unit, and inputs a signal for an operation different from the air operation (touch operation) by the user 230. Separately from the above-mentioned user 230 who performs a touch operation on the floating image 3 in space, the operation input unit 1107 may be used, for example, by an administrator to operate the floating image display device 1000.

[0082] The video signal input unit 1131 connects to an external video output device and inputs video data. Various digital video input interfaces can be considered for the video signal input unit 1131. For example, it may be configured with a video input interface compliant with the HDMI (Registered Trademark) (High-Definition Multimedia Interface) standard, a video input interface compliant with the DVI (Digital Visual Interface) standard, or a video input interface compliant with the DisplayPort standard.

[0083] Alternatively, an analog video input interface such as analog RGB or composite video may be provided. The audio signal input unit 1133 connects to an external audio output device and inputs audio data. The audio signal input unit 1133 may be configured with an audio input interface compliant with the HDMI standard, an optical digital terminal interface, or a coaxial digital terminal interface, etc. In the case of an interface compliant with the HDMI standard, the video signal input unit 1131 and the audio signal input unit 1133 may be configured as an integrated interface with integrated terminals and cables. The audio output unit 1140 is capable of outputting audio based on the audio data input to the audio signal input unit 1133. The audio output unit 1140 may be composed of speakers.

[0084] Also, the audio output unit 1140 may output built-in operation sounds or error warning sounds. Alternatively, the audio output unit 1140 may be configured to output digital signals to external devices, such as the Audio Return Channel function defined in the HDMI standard. The microphone 1139 is a microphone that picks up sounds around the spatial floating video display device 1000, converts them into signals, and generates audio signals. It may be configured such that the microphone records the voice of a person, such as the user's voice, and the control unit 1110, which will be described later, performs speech recognition processing on the generated audio signal to obtain character information from the audio signal.

[0085] The non-volatile memory 1108 stores various data used in the spatial floating image display device 1000. The data stored in the non-volatile memory 1108 includes, for example, data for various operations to be displayed in the spatial floating image 3, display icons, data of objects to be operated by the user's operations, layout information, and the like. The memory 1109 stores video data to be displayed as the spatial floating image 3, control data of the device, and the like.

[0086] The control unit 1110 controls the operations of each connected unit. Further, the control unit 1110 may perform arithmetic processing based on information acquired from each unit within the spatial floating image display device 1000 in cooperation with a program stored in the memory 1109.

[0087] The communication unit 1132 communicates with external devices, external servers, etc. via a wired or wireless communication interface. When the communication unit 1132 has a wired communication interface, the wired communication interface may be configured, for example, as a LAN interface conforming to the Ethernet standard. When the communication unit 1132 has a wireless communication interface, it may be configured, for example, as a communication interface of the Wi-Fi method, a communication interface of the Bluetooth method, a mobile communication interface such as 4G or 5G. Through the communication via the communication unit 1132, various data such as video data, image data, and audio data are transmitted and received.

[0088] Also, the removable media interface 1134 is an interface for connecting a removable recording medium (removable media). The removable recording medium (removable media) may be composed of a semiconductor element memory such as a solid state drive (SSD), a magnetic recording medium recording device such as a hard disk drive (HDD), or an optical recording medium such as an optical disk. The removable media interface 1134 can read various information such as various data including video data, image data, and audio data recorded on the removable recording medium. The video data, image data, etc. recorded on the removable recording medium are output as the spatial floating image 3 via the video display unit 1102 and the retroreflective unit 1101.

[0089] The storage unit 1170 is a storage device for recording various information such as various data including video data, image data, and audio data. The storage unit 1170 may be composed of a magnetic recording medium recording device such as a hard disk drive (HDD) or a semiconductor element memory such as a solid state drive (SSD). For example, various information such as various data including video data, image data, and audio data may be recorded in the storage unit 1170 in advance when the product is shipped. Also, the storage unit 1170 may record various information such as various data including video data, image data, and audio data acquired from an external device or an external server via the communication unit 1132.

[0090] The video data, image data, etc. recorded in the storage unit 1170 are output as the spatial floating image 3 via the video display unit 1102 and the retroreflective unit 1101. The video data, image data, etc. such as display icons and objects for the user to operate, which are displayed as the spatial floating image 3, are also recorded in the storage unit 1170.

[0091] The layout information of display icons, objects, etc. and various metadata information related to the objects, which are displayed as the spatial floating image 3, are also recorded in the storage unit 1170. The audio data recorded in the storage unit 1170 is output as audio from, for example, the audio output unit 1140.

[0092] The video control unit 1160 performs various controls on the video signal input to the video display unit 1102. The video control unit 1160 may be referred to as a video processing circuit and may be composed of hardware such as an ASIC, an FPGA, or a video processor. Note that the video control unit 1160 may also be referred to as a video processing unit or an image processing unit. The video control unit 1160 performs controls such as video switching, for example, which video signal among the video signals stored in the memory 1109 and the video signals (video data) input to the video signal input unit 1131 is to be input to the video display unit 1102.

[0093] Also, the video control unit 1160 may generate a superimposed video signal by superimposing the video signal stored in the memory 1109 and the video signal input from the video signal input unit 1131, and perform control to form a composite video as the floating video 3 in space by inputting the superimposed video signal to the video display unit 1102.

[0094] Also, the video control unit 1160 may perform control to perform image processing on the video signal input from the video signal input unit 1131, the video signal stored in the memory 1109, etc. Examples of the image processing include scaling processing such as enlarging, reducing, and deforming an image, brightness adjustment processing for changing brightness, contrast adjustment processing for changing the contrast curve of an image, and Retinex processing for decomposing an image into light components and changing the weighting for each component.

[0095] Also, the video control unit 1160 may perform special effect video processing or the like to assist the in-air operation (touch operation) of the user 230 on the video signal input to the video display unit 1102. The special effect video processing is performed based on, for example, the detection result of the touch operation of the user 230 by the in-air operation detection unit 1350 or the captured image of the user 230 by the imaging unit 1180.

[0096] The posture sensor 1113 is a sensor composed of a gravity sensor, an acceleration sensor, or a combination thereof, and can detect the posture in which the spatial floating video display device 1000 is installed. Based on the posture detection result of the posture sensor 1113, the control unit 1110 may control the operations of the connected components. For example, when an unfavorable posture as the user's usage state is detected, the control may be performed to stop the display of the video being displayed on the video display unit 1102 and display an error message to the user. Alternatively, when the posture sensor 1113 detects that the installation posture of the spatial floating video display device 1000 has changed, the control may be performed to rotate the orientation of the video being displayed on the video display unit 1102.

[0097] As described so far, the spatial floating video display device 1000 is equipped with various functions. However, the spatial floating video display device 1000 does not necessarily need to have all of these functions, and any configuration may be used as long as it has the function of forming the spatial floating video 3.

[0098] <Configuration Example of Spatial Floating Video Display Device> Next, a configuration example of the spatial floating video display device will be described. The layout of the components of the spatial floating video display device according to this embodiment can have various layouts according to the usage form. Hereinafter, each layout of FIGS. 4A to 4M will be described. In any of the examples of FIGS. 4A to 4M, the thick line surrounding the spatial floating video display device 1000 shows an example of the housing structure of the spatial floating video display device 1000.

[0099] Figure 4A is a diagram showing an example of the configuration of a spatial floating image display device. The spatial floating image display device 1000 shown in Figure 4A is equipped with an optical system corresponding to the optical system of Figure 2A. In the spatial floating image display device 1000 shown in Figure 4A, it is installed horizontally so that the surface on which the spatial floating image 3 is formed faces upward. That is, in Figure 4A, a transparent member 100 is installed on the upper surface of the spatial floating image display device 1000. The spatial floating image 3 is formed above the surface of the transparent member 100 of the spatial floating image display device 1000. The light of the spatial floating image 3 travels in an obliquely upward direction. When the air operation detection sensor 1351 is provided as shown in the figure, the operation of the spatial floating image 3 by the finger of the user 230 can be detected. Here, the x-direction is the left-right direction as seen from the user, the y-direction is the front-back direction (depth direction) as seen from the user, and the z-direction is the up-down direction (vertical direction). Hereinafter, since the definitions of the x-direction, y-direction, and z-direction are the same in each figure of Figure 4, repeated explanations will be omitted.

[0100] Figure 4B is a diagram showing an example of the configuration of a spatial floating image display device. The spatial floating image display device 1000 shown in Figure 4B is equipped with an optical system corresponding to the optical system of Figure 2A. The spatial floating image display device 1000 shown in Figure 4B is installed vertically so that the surface on which the spatial floating image 3 is formed faces the front (the direction of the user 230) of the spatial floating image display device 1000. That is, in Figure 4B, a transparent member 100 is installed on the front (the direction of the user 230) of the spatial floating image display device. The spatial floating image 3 is formed on the user 230 side with respect to the surface of the transparent member 100 of the spatial floating image display device 1000. The light of the spatial floating image 3 travels in an obliquely upward direction. When the air operation detection sensor 1351 is provided as shown in the figure, the operation of the spatial floating image 3 by the finger of the user 230 can be detected. Here, as shown in Figure 4B, the air operation detection sensor 1351 can use the reflection of the sensing light by the user's nail for touch detection by sensing the finger of the user 230 from above. Generally, since the nail has a higher reflectivity than the finger pad, the accuracy of touch detection can be improved by configuring it in this way.

[0101] FIG. 4C is a diagram showing an example of the configuration of the airborne floating image display device. The airborne floating image display device 1000 shown in FIG. 4C is equipped with an optical system corresponding to the optical system of FIG. 2B. In the airborne floating image display device 1000 shown in FIG. 4C, it is installed horizontally so that the surface on which the airborne floating image 3 is formed faces upward. That is, in FIG. 4C, for the airborne floating image display device 1000, a transparent member 100 is installed on the upper surface of the device. The airborne floating image 3 is formed above the surface of the transparent member 100 of the airborne floating image display device 1000. The light of the airborne floating image 3 travels in an obliquely upward direction. When the airborne operation detection sensor 1351 is provided as shown in the figure, the operation of the airborne floating image 3 by the finger of the user 230 can be detected.

[0102] FIG. 4D is a diagram showing an example of the configuration of the airborne floating image display device. The airborne floating image display device 1000 shown in FIG. 4D is equipped with an optical system corresponding to the optical system of FIG. 2B. The airborne floating image display device 1000 shown in FIG. 4D is installed vertically so that the surface on which the airborne floating image 3 is formed faces the front (the direction of the user 230) of the airborne floating image display device 1000. That is, in FIG. 4D, for the airborne floating image display device 1000, a transparent member 100 is installed on the front (the direction of the user 230) of the device. The airborne floating image 3 is formed on the user 230 side with respect to the surface of the transparent member 100 of the airborne floating image display device 1000. The light of the airborne floating image 3 travels in an obliquely upward direction. When the airborne operation detection sensor 1351 is provided as shown in the figure, the operation of the airborne floating image 3 by the finger of the user 230 can be detected. Here, as shown in FIG. 4D, the airborne operation detection sensor 1351 can utilize the reflection of the sensing light by the user's nail for touch detection by sensing the finger of the user 230 from above. Generally, since the nail has a higher reflectivity than the finger pad, the accuracy of touch detection can be improved by configuring it in this way.

[0103] FIG. 4E is a diagram showing an example of the configuration of the spatial floating image display device. The spatial floating image display device 1000 shown in FIG. 4E is equipped with an optical system corresponding to the optical system of FIG. 2C. In the spatial floating image display device 1000 shown in FIG. 4E, it is installed horizontally so that the surface on which the spatial floating image 3 is formed faces upward. That is, in FIG. 4E, in the spatial floating image display device 1000, a transparent member 100 is installed on the upper surface of the device. The spatial floating image 3 is formed above the surface of the transparent member 100 of the spatial floating image display device 1000. The light of the spatial floating image 3 travels in the directly upward direction. When the air operation detection sensor 1351 is provided as shown in the figure, the operation of the spatial floating image 3 by the finger of the user 230 can be detected.

[0104] FIG. 4F is a diagram showing an example of the configuration of the spatial floating image display device. The spatial floating image display device 1000 shown in FIG. 4F is equipped with an optical system corresponding to the optical system of FIG. 2C. The spatial floating image display device 1000 shown in FIG. 4F is installed vertically so that the surface on which the spatial floating image 3 is formed faces the front (the direction of the user 230) of the spatial floating image display device 1000. That is, in FIG. 4F, in the spatial floating image display device 1000, a transparent member 100 is installed on the front (the direction of the user 230) of the device. The spatial floating image 3 is formed on the user 230 side with respect to the surface of the transparent member 100 of the spatial floating image display device 1000. The light of the spatial floating image 3 travels in the direction in front of the user's hand. When the air operation detection sensor 1351 is provided as shown in the figure, the operation of the spatial floating image 3 by the finger of the user 230 can be detected.

[0105] FIG. 4G is a diagram showing an example of the configuration of the spatial floating image display device. The spatial floating image display device 1000 shown in FIG. 4G is equipped with an optical system corresponding to the optical system of FIG. 2C. In the optical systems of the spatial floating image display devices from FIGS. 4A to 4F, the central optical path of the image light emitted from the display device 1 was on the yz plane. That is, in the optical systems of the spatial floating image display devices from FIGS. 4A to 4F, the image light traveled in the front-rear direction and the up-down direction as viewed by the user. On the other hand, in the optical system of the spatial floating image display device shown in FIG. 4G, the central optical path of the image light emitted from the display device 1 is on the xy plane. That is, in the optical system of the spatial floating image display device shown in FIG. 4G, the image light travels in the left-right direction and the front-rear direction as viewed by the user. In the spatial floating image display device 1000 shown in FIG. 4G, the surface on which the spatial floating image 3 is formed is installed so as to face the front of the device (the direction of the user 230). That is, in FIG. 4G, in the spatial floating image display device 1000, the transparent member 100 is installed on the front of the device (the direction of the user 230). The spatial floating image 3 is formed on the surface of the transparent member 100 of the spatial floating image display device 1000 on the user side. The light of the spatial floating image 3 travels in the direction in front of the user. When the air operation detection sensor 1351 is provided as shown in the figure, the operation of the spatial floating image 3 by the finger of the user 230 can be detected.

[0106] FIG. 4H is a diagram showing an example of the configuration of the spatial floating image display device. The spatial floating image display device 1000 in FIG. 4H is different from the spatial floating image display device in FIG. 4G in that it has a window with a transparent plate 100B such as glass or plastic on the back of the device (the side opposite to the position where the user 230 views the spatial floating image 3, that is, the side opposite to the traveling direction of the image light of the spatial floating image 3 toward the user 230). Regarding the other configurations, since they are the same as those of the spatial floating image display device in FIG. 4G, repeated descriptions are omitted. The spatial floating image display device 1000 in FIG. 4H is provided with a window having a transparent plate 100B at a position on the opposite side of the traveling direction of the image light of the spatial floating image 3 with respect to the spatial floating image 3. Therefore, when the user 230 views the spatial floating image 3, the scenery on the rear side of the spatial floating image display device 1000 can be recognized as the background of the spatial floating image 3. Therefore, the user 230 can recognize that the spatial floating image 3 is floating in the air in front of the scenery on the rear side of the spatial floating image display device 1000. Thereby, the floating feeling of the spatial floating image 3 in the air can be emphasized more.

[0107] Note that depending on the polarization distribution of the image light output from the display device 1 and the performance of the polarization separation member 101B, a part of the image light output from the display device 1 may be reflected by the polarization separation member 101B and may go toward the transparent plate 100B. Depending on the coating performance of the surface of the transparent plate 100B, this light may be reflected again on the surface of the transparent plate 100B and be visually recognized by the user as stray light. Therefore, in order to prevent the stray light, the window on the back of the spatial floating image display device 1000 may be configured not to be provided with the transparent plate 100B.

[0108] FIG. 4I is a diagram showing an example of the configuration of the spatial floating image display device. The spatial floating image display device 1000 in FIG. 4I is different from the spatial floating image display device in FIG. 4H in that an opening / closing door 1410 for light shielding is provided in the window of the transparent plate 100B arranged on the back of the device (the side opposite to the position where the user 230 views the spatial floating image 3). Regarding the other configurations, since they are the same as those of the spatial floating image display device in FIG. 4H, repeated descriptions are omitted.

[0109] The opening / closing door 1410 of the spatial floating image display device 1000 in FIG. 4I has, for example, a light-shielding plate, and is provided with a mechanism for moving (sliding), rotating, or attaching / detaching the light-shielding plate, so that the window (rear-side window) of the transparent plate 100B located on the back side of the spatial floating image display device 1000 can be switched between an open state and a light-shielded state. The movement (sliding) or rotation of the light-shielding plate by the opening / closing door 1410 may be an electric type driven by a motor (not shown). The motor may be controlled by the control unit 1110 in FIG. 3. In the example of FIG. 4I, an example of two light-shielding plates of the opening / closing door 1410 is disclosed. In contrast, the number of light-shielding plates of the opening / closing door 1410 may be one.

[0110] For example, when the scenery visible through the window of the transparent plate 100B of the spatial floating image display device 1000 is outdoors, the brightness of sunlight varies depending on the weather. When the outdoor sunlight is strong, the background of the spatial floating image 3 may become too bright, and the visibility of the spatial floating image 3 for the user 230 may decrease. In such a case, if the rear-side window is shielded from light by moving (sliding), rotating, or attaching the light-shielding plate of the opening / closing door 1410, the background of the spatial floating image 3 will become darker, so that the visibility of the spatial floating image 3 can be relatively increased. Such a shielding operation by the light-shielding plate of the opening / closing door 1410 may be directly performed by the force of the user 230's hand. The control unit 1110 may control a motor (not shown) according to an operation input via the operation input unit 1107 in FIG. 3 to perform a shielding operation by the light-shielding plate of the opening / closing door 1410.

[0111] In addition, an illuminance sensor may be provided on the back side (opposite side of the user 230) of the spatial floating image display device 1000, such as near the rear-side window, to measure the brightness of the space in front of the rear-side window. In this case, the control unit 1110 in FIG. 3 may control a motor (not shown) according to the detection result of the illuminance sensor to perform an opening / closing operation by the light-shielding plate of the opening / closing door 1410. By controlling the opening / closing operation by the light-shielding plate of the opening / closing door 1410 in this way, it is possible to more preferably maintain the visibility of the spatial floating image 3 without the user 230 manually performing the opening / closing operation of the light-shielding plate of the opening / closing door 1410.

[0112] Also, the light-shielding plate by the opening / closing door 1410 may be manually detachable. Depending on the usage and installation environment of the spatial floating image display device 1000, the user can select whether to keep the rear window in an open state or a light-shielded state. If it is planned to use the rear window in a light-shielded state for a long time, the detachable light-shielding plate can be fixed in the light-shielded state. Also, if it is planned to use the rear window in an open state for a long time, it can be used with the detachable light-shielding plate removed. For attaching and detaching the light-shielding plate, screws, a hook structure, or a fitting structure may be used.

[0113] In the example of the spatial floating image display device 1000 in FIG. 4I as well, depending on the polarization distribution of the image light output from the display device 1 and the performance of the polarization separation member 101B, a part of the image light output from the display device 1 may be reflected by the polarization separation member 101B and directed toward the transparent plate 100B. Depending on the coating performance of the surface of the transparent plate 100B, this light may be reflected again on the surface of the transparent plate 100B and visually recognized by the user as stray light. Therefore, in order to prevent such stray light, the window on the back of the spatial floating image display device 1000 may be configured not to be provided with the transparent plate 100B. The above-described opening / closing door 1410 may be provided on the window without the transparent plate 100B. In order to prevent the stray light, it is desirable that the inner surface of the housing of the light-shielding plate of the above-described opening / closing door 1410 has a low light reflectance coating or material.

[0114] FIG. 4J is a diagram showing an example of the configuration of a spatial floating image display device. The spatial floating image display device 1000 in FIG. 4J is different in that an electronically controlled variable transmittance device 1620 is arranged on the rear window of the spatial floating image display device in FIG. 4H instead of arranging a transparent plate 100B made of glass or plastic. Since the other configurations are the same as those of the spatial floating image display device in FIG. 4H, repeated description will be omitted. An example of the electronically controlled variable transmittance device 1620 is a liquid crystal shutter or the like.

[0115] That is, the liquid crystal shutter can control the transmitted light of light by voltage-controlling a liquid crystal element sandwiched between two polarizing plates. Therefore, if the liquid crystal shutter is controlled to increase the transmittance, the background of the spatial floating image 3 will be in a state where the scenery through the rear window can be seen through. Also, if the liquid crystal shutter is controlled to increase the transmittance, the scenery through the rear window as the background of the spatial floating image 3 can be made invisible. Also, since the liquid crystal shutter can control the intermediate length, it can also be set to a state such as a transmittance of 50%. For example, the control unit 1110 may control the transmittance of the electronically controlled variable transmittance device 1620 according to an operation input via the operation input unit 1107 in FIG. 3. With this configuration, when one wants to see the scenery through the rear window as the background of the spatial floating image 3, but the scenery through the rear window as the background is too bright and the visibility of the spatial floating image 3 decreases, the visibility of the spatial floating image 3 can be adjusted by adjusting the transmittance of the electronically controlled variable transmittance device 1620.

[0116] In addition, an illuminance sensor may be provided on the rear side (opposite side of the user 230) of the spatial floating image display device 1000, such as near the rear window, to measure the brightness of the space in front of the rear window. In this case, the control unit 1110 in FIG. 3 may control the transmittance of the electronically controlled variable transmittance device 1620 according to the detection result of the illuminance sensor. In this way, even if the user 230 does not perform an operation input via the operation input unit 1107 in FIG. 3, the transmittance of the electronically controlled variable transmittance device 1620 can be adjusted according to the brightness of the space in front of the rear window, so that the visibility of the spatial floating image 3 can be maintained more suitably.

[0117] Also, in the above example, an example of a liquid crystal shutter was described as the electronically controlled variable transmittance device 1620. In contrast, as another example of the electronically controlled variable transmittance device 1620, electronic paper may be used. Even when using electronic paper, the same effects as described above can be obtained. Moreover, the power consumption for maintaining the intermediate tone state of electronic paper is very small. Therefore, compared with the case of adopting a liquid crystal shutter, a spatial floating image display device with low power consumption can be realized.

[0118] Figure 4K is a diagram showing an example of the configuration of the floating image display device. The floating image display device 1000 in Figure 4K is different from the floating image display device in Figure 4G in that it has a transmissive self-emitting image display device 1650 instead of the transparent member 100. Since the other configurations are the same as those of the floating image display device in Figure 4G, repeated descriptions are omitted.

[0119] In the floating image display device 1000 of Figure 4K, after the image light beam passes through the display surface of the transmissive self-emitting image display device 1650, a floating image 3 is formed outside the floating image display device 1000. That is, when an image is being displayed on the transmissive self-emitting image display device 1650, which is a two-dimensional plane display, the floating image 3 can be displayed as an image that pops out further on the user side in front of the image of the transmissive self-emitting image display device 1650. At this time, the user 230 can simultaneously view two images with different depth positions. The transmissive self-emitting image display device 1650 may be configured using existing technologies such as transmissive organic EL panels disclosed in, for example, Japanese Patent Application Laid-Open No. 2014-216761. Although not shown in Figure 3, the transmissive self-emitting image display device 1650 may be configured to be connected to other processing units such as the control unit 1110 as a component of the floating image display device 1000 in Figure 3.

[0120] Here, if an effect such as moving only an object such as a character to the floating image 3 on the front side after displaying both an object such as a background and a character on the transmissive self-emitting image display device 1650 is performed, an effective surprise effect video experience can be provided to the user 230.

[0121] Also, if the inside of the airborne video display device 1000 is made light-shielded, the background of the transmissive self-luminous video display device 1650 will become sufficiently dark. Therefore, when no video is displayed on the display device 1 or the light source of the display device 1 is turned off and video is displayed only on the transmissive self-luminous video display device 1650, to the user 230, the transmissive self-luminous video display device 1650 appears to be a normal two-dimensional flat display rather than a transmissive display. (Since the airborne video 3 in the embodiment of the present invention is displayed as an optical image of a real image in a space without a screen, if the light source of the display device 1 is turned off, the planned display position of the airborne video 3 will be a space with nothing.) Therefore, when the transmissive self-luminous video display device 1650 is used to display video as if it were a general two-dimensional flat display, by suddenly displaying a character, an object, etc. as an airborne video 3 in the air, an effective surprise performance-based video experience can be provided to the user 230.

[0122] Incidentally, the darker the inside of the airborne video display device 1000 is made, the more the transmissive self-luminous video display device 1650 appears as a two-dimensional flat display. Therefore, an absorption-type polarizing plate (not shown) that transmits the polarization of the video light reflected by the polarization separation member 101B and absorbs a polarization having a phase difference of about 90° from the said polarization may be provided on the inner side surface of the transmissive self-luminous video display device 1650 with respect to the airborne video display device 1000 (the incident surface of the video light reflected by the polarization separation member 101B to the transmissive self-luminous video display device 1650, that is, the surface of the transmissive self-luminous video display device 1650 opposite to the airborne video 3). By doing so, the influence on the video light forming the airborne video 3 is not so great, but the light incident from the outside into the inside of the airborne video display device 1000 through the transmissive self-luminous video display device 1650 can be significantly reduced, the inside of the airborne video display device 1000 can be made darker, which is preferable.

[0123] Figure 4L is a diagram showing an example of the configuration of the spatial floating image display device. The spatial floating image display device 1000 in Figure 4L is a modified example of the spatial floating image display device in Figure 4K. The orientation of the configuration arrangement in the spatial floating image display device 1000 is different from that of the spatial floating image display device in Figure 4K, and is arranged close to the spatial floating image display device in Figure 4F. Regarding the functions, operations, etc. of each configuration, since it has the same configuration as the spatial floating image display device in Figure 4K, repeated explanations are omitted.

[0124] In the spatial floating image display device of Figure 4L as well, after the light beam of the video light passes through the transmissive self-emitting image display device 1650, the spatial floating image 3 is formed on the user 230 side rather than the transmissive self-emitting image display device 1650.

[0125] In both the example of the spatial floating image display device in Figure 4K and the example of the spatial floating image display device in Figure 4L, from the user 230, the spatial floating image 3 is displayed overlapping in front of the image of the transmissive self-emitting image display device 1650. Here, the position of the spatial floating image 3 and the position of the image of the transmissive self-emitting image display device 1650 are configured to have a difference in the depth direction. Therefore, when the user moves the head (the position of the viewpoint), the depth of the two images can be recognized due to parallax. Therefore, by displaying two images with different depth positions, a three-dimensional video experience can be more suitably provided to the user without the need for stereoscopic glasses or the like and with the naked eye.

[0126] Figure 4M is a diagram showing an example of the configuration of the spatial floating image display device. The spatial floating image display device 1000 in Figure 4M is provided with a second display device 1680 on the back side as viewed from the user with respect to the polarization separation member 101B of the spatial floating image display device in Figure 4G. Regarding other configurations, since it has the same configuration as the spatial floating image display device in Figure 4G, repeated explanations are omitted.

[0127] In the configuration example shown in FIG. 4M, the second display device 1680 is provided on the back side of the display position of the spatial floating image 3, and the image display surface is directed toward the spatial floating image 3. With such a configuration, from the perspective of the user 230, the images displayed at two positions with different depths, namely, the image of the second display device 1680 and the spatial floating image 3, can be visually recognized in an overlapping manner. That is, it can be said that the second display device 1680 is arranged in such a direction as to display an image in the direction of the user 230 who views the spatial floating image 3. Although the second display device 1680 is not shown in FIG. 3, it may be configured to be connected to other processing units such as the control unit 1110 as a component of the spatial floating image display device 1000 in FIG. 3.

[0128] Note that the image light of the second display device 1680 of the spatial floating image display device 1000 in FIG. 4M is visually recognized by the user 230 after passing through the polarization separation member 101B. Therefore, in order for the image light of the second display device 1680 to more preferably pass through the polarization separation member 101B, it is desirable that the image light output from the second display device 1680 be polarized light with a polarization direction in which the polarization separation member 101B more preferably passes. That is, it is desirable that the polarization direction be the same as the polarization direction of the image light output from the display device 1. For example, when the image light output from the display device 1 is S-polarized light, it is desirable that the image light output from the second display device 1680 is also S-polarized light. Also, when the image light output from the display device 1 is P-polarized light, it is desirable that the image light output from the second display device 1680 is also P-polarized light.

[0129] The example of the spatial floating image display device in FIG. 4M also has the same effect as the example of the spatial floating image display device in FIG. 4K and the example of the spatial floating image display device in FIG. 4L in that a second image is displayed behind the spatial floating image 3. However, different from the example of the spatial floating image display device in FIG. 4K and the example of the spatial floating image display device in FIG. 4L, in the example of the spatial floating image display device in FIG. 4M, the light beam of the image light for forming the spatial floating image 3 does not pass through the second display device 1680. Therefore, the second display device 1680 does not need to be a transmissive self-luminous image display device, and a liquid crystal display which is a two-dimensional plane display may be sufficient. The second display device 1680 may also be an organic EL display. Therefore, in the example of the spatial floating image display device in FIG. 4M, it is possible to realize the spatial floating image display device 1000 at a lower cost than the example of the spatial floating image display device in FIG. 4K and the example of the spatial floating image display device in FIG. 4L.

[0130] Here, depending on the polarization distribution of the image light output from the display device 1 and the performance of the polarization separation member 101B, a part of the image light output from the display device 1 may be reflected by the polarization separation member 101B and may be directed toward the second display device 1680. This light (a part of the image light) may be reflected again on the surface of the second display device 1680 and may be visually recognized by the user as stray light.

[0131] Therefore, in order to prevent such stray light, an absorption type polarizing plate may be provided on the surface of the second display device 1680. In this case, the absorption type polarizing plate may be an absorption type polarizing plate that transmits the polarization wave of the image light output from the second display device 1680 and absorbs a polarization wave whose phase is 90° different from the polarization wave of the image light output from the second display device 1680. When the second display device 1680 is a liquid crystal display, an absorption type polarizing plate also exists on the image emission side inside the liquid crystal display. However, when there is a cover glass (cover glass on the image display surface side) on the further emission surface of the absorption type polarizing plate on the image emission side inside the liquid crystal display, stray light generated by the reflection of the cover glass by light from outside the liquid crystal display cannot be prevented. Therefore, it is necessary to separately provide the above-described absorption type polarizing plate on the surface of the cover glass.

[0132] When displaying an image on the second display device 1680 which is a two-dimensional plane display, a spatial floating image 3 can be displayed as an image further on the user side in front of the image of the second display device 1680. At this time, the user 230 can simultaneously view two images with different depth positions. By displaying a character on the spatial floating image 3 and displaying a background on the second display device 1680, an effect can be provided such that the user 230 visually recognizes a space where the character exists in a three-dimensional manner.

[0133] In addition, after displaying both an object such as a background and a character on the second display device 1680, if an effect such as moving only an object such as a character to the spatial floating image 3 on the front side is performed, a video experience with an effective surprise effect can be provided to the user 230.

[0134] Next, FIG. 4N is a diagram showing an example of the configuration of a spatial floating image display device. The spatial floating image display device 1000 in FIG. 4N is a spatial floating image display device that employs the optical system of FIG. 2D. Similar to the example of the spatial floating image display device that employs the optical systems of FIGS. 2A to 2C, an image light that has passed through the transparent member 100 forms an image in the air as the spatial floating image 3. Further, using the sensing light of the air operation detection sensor 1351 disposed on the back side of the transparent member 100 as viewed from the user, the operation of the spatial floating image 3 by the user's finger 9004 can be detected.

[0135] In the example of the spatial floating image display device that employs the optical systems of FIGS. 2A to 2C and in the example of the spatial floating image display device that employs the optical system of FIG. 2D, the spatial floating image 3 forms an image in front of the transparent member 100, and using the sensing light of the air operation detection sensor 1351 disposed on the back side of the transparent member 100 as viewed from the user, the operation of the spatial floating image 3 by the user's finger can be detected. Therefore, the spatial floating image display device that employs the optical system of FIG. 2D has a different optical system from the spatial floating image display device in which the optical systems of FIGS. 2A to 2C are disposed on the back side of the transparent member 100 as viewed from the user.

[0136] However, the usability of the spatial floating image display device employing the optical system of FIG. 2D as seen by the user is almost the same as that of the spatial floating image display device employing the optical systems of FIGS. 2A to 2C.

[0137] Next, FIG. 4O is a diagram showing an example of the configuration of the spatial floating image display device. FIG. 4O is a diagram showing the configuration of the internal optical system of the spatial floating image display device 1000 in FIG. 4N as well. The spatial floating image display device 1000 shown in FIG. 4O is equipped with an optical system corresponding to the optical system of FIG. 2D. The spatial floating image display device 1000 shown in FIG. 4O is installed horizontally so that the surface on the side where the spatial floating image 3 is formed faces upward.

[0138] That is, in FIG. 4O, for the spatial floating image display device 1000, the transparent member 100 is installed on the upper surface of the device. The spatial floating image 3 is formed above the surface of the transparent member 100 of the spatial floating image display device 1000. The light of the spatial floating image 3 travels in an obliquely upward direction. When the air operation detection sensor 1351 is provided as shown in the figure, the operation of the spatial floating image 3 by the finger of the user 230 can be detected.

[0139] Here, the configuration of FIG. 4O is compared with the configuration of FIG. 4A to confirm the differences. In FIG. 4A, the display device 1 and the spatial floating image 3 are in a plane-symmetrical relationship with respect to the surface of the polarization separation member 101. In contrast, in FIG. 4O, the display device 1 and the spatial floating image 3 are in a plane-symmetrical relationship with respect to the surface of the retroreflective plate 5. Also, in the configuration of FIG. 4A, there are the retroreflective plate 2 and the λ / 4 plate 21, but these do not exist in FIG. 4O. Further, in FIG. 4A, it is more preferable to have the absorption type polarizing plate 12, but in FIG. 4O, the absorption type polarizing plate 12 is not particularly necessary.

[0140] That is, in order to replace the optical system of FIG. 2A in the configuration of FIG. 4A with the optical system of FIG. 2D and replace it with the configuration of FIG. 4O, the following steps can be taken. That is, the polarization separation member 101 in the configuration of FIG. 4A can be replaced with the retroreflector 5, and the retroreflector 2 and the λ / 4 plate 21 can be removed from the configuration of FIG. 4A. The absorption type polarizing plate 12 may or may not be present. By performing the replacement based on this idea, the optical systems of FIGS. 2A to 2C mounted in the configuration of the spatial floating image display device of FIGS. 4A to 4G can be replaced with the optical system of FIG. 2D, and the spatial floating image display device equipped with the optical system of FIG. 2D can be replaced. At this time, in FIGS. 4A and 4B, the polarization separation member 101 may be replaced with the retroreflector 5, and in FIGS. 4C to 4G, the polarization separation member 101B may be replaced with the retroreflector 5.

[0141] By doing so, a spatial floating image display device in which the optical system in the configuration of the spatial floating image display device of FIGS. 4A to 4G is replaced with the optical system of FIG. 2D can be realized. Even in these spatial floating image display devices replaced with the optical system of FIG. 2D, a spatial floating image display device with almost the same usability as the spatial floating image display device of FIGS. 4A to 4G can be realized.

[0142] <Display device> Next, the display device 1 of this embodiment will be described with reference to the drawings. The display device 1 of this embodiment includes a light source device 13 that constitutes its light source together with an image display element 11 (liquid crystal display panel). In FIG. 5, the light source device 13 is shown as an exploded perspective view together with the liquid crystal display panel.

[0143] This liquid crystal display panel (image display element 11) receives, as shown by the arrow 30 in FIG. 5, an illumination light beam from the light source device 13, which is a backlight device, and has a diffusion characteristic with a sandwiching angle, that is, a characteristic similar to that of a laser beam with strong directivity (linear propagation) and the polarization plane aligned in one direction. The liquid crystal display panel (image display element 11) modulates the received illumination light beam according to the input video signal. The modulated video light is reflected by the retroreflector 2, transmitted through the transparent member 100, and forms a spatial floating image that is a real image (see FIG. 1).

[0144] In addition, in FIG. 5, the liquid crystal display panel 11 constituting the display device 1, further includes a light direction conversion panel 54 that controls the directivity characteristics of the emitted light beam from the light source device 13, and an included angle diffuser plate (not shown) as needed. That is, polarizing plates are provided on both sides of the liquid crystal display panel 11, and video light of a specific polarization modulates the intensity of light according to the video signal and emits it (refer to arrow 30 in FIG. 5). As a result, a desired video is projected as light of a specific polarization with high directivity (linear propagation property) through the light direction conversion panel 54 toward the retroreflective plate 2. After being reflected by the retroreflective plate 2, it passes through and forms a spatial floating video 3 toward the eyes of a monitor outside the store (space). A protective cover 50 (refer to FIGS. 6 and 7) may be provided on the surface of the above-described light direction conversion panel 54.

[0145] <Example 1 of Display Device> FIG. 6 shows an example of the specific configuration of the display device 1. In FIG. 6, the liquid crystal display panel 11 and the light direction conversion panel 54 are arranged on the light source device 13 of FIG. 5. This light source device 13 is formed of, for example, plastic on the case shown in FIG. 5, and houses an LED element 201 and a light guide 203 inside. On the end face of the light guide 203, as also shown in FIG. 5 and the like, in order to convert the divergent light emitted from each LED element 201 into a substantially parallel light beam, it has a shape in which the cross-sectional area gradually increases toward the opposite side of the light receiving part, and has a lens shape that has an effect of gradually reducing the divergence angle by total internal reflection a plurality of times when propagating inside. The liquid crystal display panel 11 constituting such a display device 1 is attached to the upper surface of the display device 1. In addition, on one side surface (the left end surface in this example) of the case of the light source device 13, an LED (Light Emitting Diode) element 201, which is a semiconductor light source, and an LED substrate 202 on which its control circuit is mounted are attached. A heat sink, which is a member for cooling the heat generated by the LED element and the control circuit, may be attached to the outer surface of the LED substrate 202.

[0146] In addition, on the frame (not shown) of the liquid crystal display panel attached to the upper surface of the case of the light source device 13, there are attached a liquid crystal display panel 11 attached to the frame, and further, an FPC (Flexible Printed Circuits) (not shown) electrically connected to the liquid crystal display panel 11, etc. That is, the liquid crystal display panel 11, which is an image display element, together with the LED element 201, which is a solid light source, modulates the intensity of transmitted light based on a control signal from a control circuit (image control unit 1160 in FIG. 3) that constitutes the electronic device, thereby generating a display image. At this time, since the generated image light has a narrow diffusion angle and only a specific polarization component, a novel image display device that is similar to a surface-emitting laser image source driven by an image signal can be obtained. Currently, it is impossible technically and from a safety perspective to obtain a laser light beam of the same size as the image obtained by the above-described display device 1 using a laser device. Therefore, in this embodiment, for example, light similar to the above-described surface-emitting laser image light is obtained from the light beam from a general light source equipped with LED elements.

[0147] Subsequently, the configuration of the optical system housed in the case of the light source device 13 will be described in detail with reference to FIG. 7 together with FIG. 6.

[0148] Since FIGS. 6 and 7 are cross-sectional views, only one of the plurality of LED elements 201 that constitute the light source is shown, and these are converted into substantially collimated light by the shape of the light-receiving end face 203a of the light guide 203. For this reason, the light-receiving part of the light guide end face and the LED element are attached while maintaining a predetermined positional relationship.

[0149] Note that each of these light guides 203 is formed of a light-transmissive resin such as acrylic. The LED light-receiving surface at the end of this light guide 203 has, for example, an outer peripheral surface in the shape of a conical convex obtained by rotating a parabolic cross-section. At its top, it has a concave portion with a convex portion (i.e., a convex lens surface) formed at its central portion, and at the central portion of its flat portion, it has a convex lens surface protruding outward (or it may be a concave lens surface recessed inward) (not shown). Note that the outer shape of the light-receiving portion of the light guide to which the LED element 201 is attached has a parabolic surface shape that forms a conical outer peripheral surface, and is set within an angle range that allows the light emitted from the LED element in the peripheral direction to be totally reflected inside it, or a reflecting surface is formed.

[0150] On the other hand, the LED elements 201 are respectively arranged at predetermined positions on the surface of the LED substrate 202, which is their circuit board. This LED substrate 202 is arranged and fixed with respect to the LED collimator (light-receiving end face 203a) such that the LED elements 201 on its surface are respectively located at the central portions of the aforementioned concave portions.

[0151] According to such a configuration, due to the shape of the light-receiving end face 203a of the light guide 203, the light emitted from the LED element 201 can be taken out as substantially parallel light, and the utilization efficiency of the generated light can be improved.

[0152] As described above, the light source device 13 is configured by attaching a light source unit in which a plurality of LED elements 201, which are light sources, are arranged to the light-receiving end face 203a, which is the light-receiving portion provided at the end face of the light guide 203. The divergent light beam from the LED element 201 is made into substantially parallel light by the lens shape of the light-receiving end face 203a of the light guide end face, and is guided through the inside of the light guide 203 (in a direction parallel to the drawing) as shown by the arrow, and is emitted toward the liquid crystal display panel 11 arranged substantially parallel to the light guide 203 (in a direction perpendicular to the front from the drawing) by the light beam direction conversion means 204. By optimizing the distribution (density) of this light beam direction conversion means 204 according to the shape inside or on the surface of the light guide, the uniformity of the light beam incident on the liquid crystal display panel 11 can be controlled.

[0153] The above-described light beam direction conversion means 204 emits the light beam propagating in the light guide body toward the liquid crystal display panel 11 arranged substantially parallel to the light guide body 203 (in the direction perpendicular to the front from the drawing plane) by the shape of the surface of the light guide body or by providing, for example, portions with different refractive indices inside the light guide body. At this time, if the relative luminance ratio when comparing the luminance of the center and the peripheral portion of the screen in a state where the liquid crystal display panel 11 faces the center of the screen and the viewpoint is placed at the same position as the diagonal dimension of the screen is 20% or more, there is no practical problem, and if it exceeds 30%, it has more excellent characteristics.

[0154] Note that FIG. 6 is a cross-sectional layout view for explaining the configuration and operation of the light source of the present embodiment for converting polarization in the light source device 13 including the above-described light guide body 203 and the LED element 201. In FIG. 6, the light source device 13 includes, for example, a light guide body 203 provided with light beam direction conversion means 204 on its surface or inside formed of plastic or the like, an LED element 201 as a light source, a reflection sheet 205, a retardation plate 206, a lenticular lens, etc. A liquid crystal display panel 11 provided with polarizing plates on its upper surface at the light source light incident surface and the video light output surface is attached.

[0155] In addition, a film or sheet-shaped reflective polarizing plate 49 is provided on the light source light incident surface (the lower surface in the figure) of the liquid crystal display panel 11 corresponding to the light source device 13, and selectively reflects one-sided polarized wave (for example, P wave) 212 of the natural light beam 210 emitted from the LED element 210. The reflected light is reflected again by the reflection sheet 205 provided on one surface (the lower side in the figure) of the light guide body 203 so as to go toward the liquid crystal display panel 11. Therefore, a retardation plate (λ / 4 plate) is provided between the reflection sheet 205 and the light guide body 203 or between the light guide body 203 and the reflective polarizing plate 49, and the reflected light is reflected by the reflection sheet 205 and passed twice to convert the reflected light beam from P polarization to S polarization, thereby improving the utilization efficiency of the light source light as video light. The video light beam whose light intensity is modulated by the video signal in the liquid crystal display panel 11 (arrow 213 in FIG. 6) enters the retroreflective plate 2. After being reflected by the retroreflective plate 2, a spatial floating image that is a real image can be obtained.

[0156] FIG. 7 is a cross-sectional layout view for explaining the configuration and operation of the light source of this embodiment that performs polarization conversion in the light source device 13 including the light guide 203 and the LED element 201, similar to FIG. 6. Similarly, the light source device 13 is also composed of, for example, a light guide 203 provided with a light beam direction conversion means 204 on the surface or inside formed of plastic or the like, an LED element 201 as a light source, a reflection sheet 205, a retardation plate 206, a lenticular lens, and the like. On the upper surface of the light source device 13, a liquid crystal display panel 11 having polarizing plates on the light source light incident surface and the video light emitting surface is attached as a video display element.

[0157] Also, on the light source light incident surface (the lower surface in the figure) of the liquid crystal display panel 11 corresponding to the light source device 13, a film or sheet-like reflective polarizing plate 49 is provided to selectively reflect one-sided polarized waves (for example, S waves) 211 among the natural light beams 210 emitted from the LED element 201. That is, in the example of FIG. 7, the selective reflection characteristics of the reflective polarizing plate 49 are different from those in FIG. 7. The reflected light is reflected by the reflection sheet 205 provided on one (lower side in the figure) surface of the light guide 203 and then travels back toward the liquid crystal display panel 11. A retardation plate (λ / 4 plate) is provided between the reflection sheet 205 and the light guide 203 or between the light guide 203 and the reflective polarizing plate 49, and the reflected light is reflected by the reflection sheet 205 and passed through twice to convert the reflected light beam from S polarization to P polarization, thereby improving the utilization efficiency of the light source light as video light. The video light beam whose light intensity is modulated by the video signal in the liquid crystal display panel 11 (arrow 214 in FIG. 7) enters the retroreflective plate 2. After being reflected by the retroreflective plate 2, a spatial floating image that is a real image can be obtained.

[0158] In the light source devices shown in FIGS. 6 and 7, in addition to the action of the polarizing plate provided on the light incident surface of the corresponding liquid crystal display panel 11, since one-sided polarization components are reflected by the reflective polarizing plate, the theoretically obtainable contrast ratio is the reciprocal of the cross transmittance of the reflective polarizing plate multiplied by the reciprocal of the cross transmittance obtained by the two polarizing plates attached to the liquid crystal display panel. As a result, high contrast performance can be obtained. Actually, it was experimentally confirmed that the contrast performance of the displayed image was improved by more than 10 times. As a result, a high-quality video comparable to that of self-emitting organic EL was obtained.

[0159] <Example 2 of the display device> FIG. 8 shows another example of the specific configuration of the display device 1. This light source device 13 is configured by housing an LED, a collimator, a composite diffuser block, a light guide, etc. in a case made of, for example, plastic, and a liquid crystal display panel 11 is attached to the upper surface thereof. Also, on one side surface of the case of the light source device 13, LED (Light Emitting Diode) elements 14a and 14b which are semiconductor light sources and an LED substrate on which its control circuit is mounted are attached, and on the outer surface of the LED substrate, a heat sink 103 which is a member for cooling the heat generated by the LED elements and the control circuit is attached.

[0160] Also, on the liquid crystal display panel frame attached to the upper surface of the case, the liquid crystal display panel 11 attached to the frame and, further, an FPC (Flexible Printed Circuits) 403 electrically connected to the liquid crystal display panel 11 are attached and configured. That is, the liquid crystal display panel 11 which is a liquid crystal display element, together with the LED elements 14a and 14b which are solid light sources, modulates the intensity of transmitted light based on a control signal from a control circuit (not shown here) which constitutes the electronic device, thereby generating a display image.

[0161] <Example 3 of the display device> Subsequently, with reference to FIG. 9, another example (Example 3 of the display device) of the specific configuration of the display device 1 will be described. The light source device of this display device 1 converts the diverging light beam (in which P-polarized light and S-polarized light are mixed) from the LED into a substantially parallel light beam by the collimator 18 and reflects it toward the liquid crystal display panel 11 by the reflecting surface of the reflection type light guide 304. The reflected light enters the reflection type polarizing plate 49 disposed between the liquid crystal display panel 11 and the reflection type light guide 304. The reflection type polarizing plate 49 transmits light of a specific polarization (for example, P-polarized light) and makes the transmitted polarized light enter the liquid crystal display panel 11. Here, light of other polarizations (for example, S-polarized light) other than the specific polarization is reflected by the reflection type polarizing plate 49 and heads again toward the reflection type light guide 304.

[0162] The reflective polarizing plate 49 is installed at an angle with respect to the liquid crystal display panel 11 so as not to be perpendicular to the principal ray of the light from the reflecting surface of the reflective light guide 304. Then, the principal ray of the light reflected by the reflective polarizing plate 49 enters the transmissive surface of the reflective light guide 304. The light that has entered the transmissive surface of the reflective light guide 304 passes through the back surface of the reflective light guide 304, passes through the λ / 4 plate 270 which is a retardation plate, and is reflected by the reflector 271. The light reflected by the reflector 271 passes through the λ / 4 plate 270 again and passes through the transmissive surface of the reflective light guide 304. The light that has passed through the transmissive surface of the reflective light guide 304 enters the reflective polarizing plate 49 again.

[0163] At this time, since the light that enters the reflective polarizing plate 49 again has passed through the λ / 4 plate 270 twice, the polarization is converted into a polarization (for example, P-polarization) that passes through the reflective polarizing plate 49. Therefore, the light whose polarization has been converted passes through the reflective polarizing plate 49 and enters the liquid crystal display panel 11. Regarding the polarization design related to polarization conversion, the polarization directions (reversing S-polarization and P-polarization) may be configured in the reverse manner from the above description.

[0164] As a result, the light from the LED is aligned to a specific polarization (for example, P-polarization), enters the liquid crystal display panel 11, is luminance-modulated according to the video signal, and a video is displayed on the panel surface. As in the above example, a plurality of LEDs constituting the light source are shown (however, only one is shown in FIG. 9 due to the longitudinal section), and these are attached to the collimator 18 at predetermined positions.

[0165] Each of the collimators 18 is formed of, for example, a translucent resin such as acrylic or glass. The collimator 18 may have an outer peripheral surface in a conical convex shape obtained by rotating a parabolic cross-section. Further, a concave portion having a convex portion (i.e., a convex lens surface) may be formed at the central portion of the top of the collimator 18 (the side facing the LED substrate 102). Further, a convex lens surface protruding outward (or a concave lens surface recessed inward may also be acceptable) is provided at the central portion of the flat surface portion of the collimator 18 (the side opposite to the above-mentioned top). The parabolic surface forming the conical outer peripheral surface of the collimator 18 is set within an angle range capable of total reflection of the light emitted from the LED in the peripheral direction inside the collimator 18, or a reflecting surface is formed.

[0166] Note that the LEDs are respectively arranged at predetermined positions on the surface of the LED substrate 102 which is their circuit board. The LED substrate 102 is arranged and fixed with respect to the collimator 18 such that the LEDs on its surface are respectively positioned at the central portion of the top of the conical convex shape (the concave portion if there is a concave portion at the top).

[0167] According to such a configuration, among the light emitted from the LED, particularly the light emitted from the central portion thereof is condensed by the convex lens surface forming the outer shape of the collimator 18 and becomes parallel light. Further, the light emitted from other portions in the peripheral direction is reflected by the parabolic surface forming the conical outer peripheral surface of the collimator 18 and is similarly condensed to become parallel light. In other words, according to the collimator 18 having a convex lens formed at its central portion and a parabolic surface formed at its peripheral portion, almost all of the light generated by the LED can be taken out as parallel light, and the utilization efficiency of the generated light can be improved.

[0168] Furthermore, the light converted into substantially parallel light by the collimator 18 shown in FIG. 9 is reflected by the reflective light guide 304. Among this light, the light of a specific polarization passes through the reflective polarizing plate 49 due to the action of the reflective polarizing plate 49, and the light of the other polarization reflected by the action of the reflective polarizing plate 49 passes through the light guide 304 again. This light is reflected by a reflector 271 located at a position opposite to the liquid crystal display panel 11 with respect to the reflective light guide 304. At this time, the light is polarization-converted by passing through the λ / 4 plate 270, which is a retardation plate, twice. The light reflected by the reflector 271 passes through the light guide 304 again and enters the reflective polarizing plate 49 provided on the opposite surface. Since the incident light has been polarization-converted, it passes through the reflective polarizing plate 49 and is incident on the liquid crystal display panel 11 with the polarization directions aligned. As a result, all the light from the light source can be utilized, so the geometric optical utilization efficiency of the light is doubled. Also, since the polarization degree (extinction ratio) of the reflective polarizing plate is also multiplied by the extinction ratio of the entire system, the contrast ratio of the entire display device is significantly improved by using the light source device of this embodiment. Note that by adjusting the surface roughness of the reflective surface of the reflective light guide 304 and the surface roughness of the reflector 271, the light reflection diffusion angle at each reflective surface can be adjusted. The surface roughness of the reflective surface of the reflective light guide 304 and the surface roughness of the reflector 271 may be adjusted for each design so that the uniformity of the light incident on the liquid crystal display panel 11 becomes more suitable.

[0169] Note that the λ / 4 plate 270, which is the retardation plate in FIG. 9, does not necessarily need to have a retardation of λ / 4 with respect to the polarization incident perpendicular to the λ / 4 plate 270. In the configuration of FIG. 9, any retardation plate that changes the phase by 90° (λ / 2) when the polarization passes through it twice is acceptable. The thickness of the retardation plate may be adjusted according to the incident angle distribution of the polarization.

[0170] <Example 4 of the display device> Furthermore, another example (Example 4 of the display device) of the configuration of the optical system such as the light source device of the display device will be described with reference to FIG. 10. This is a configuration example in the case where a diffusion sheet is used instead of the reflective light guide 304 in the light source device of Example 3 of the display device. Specifically, two optical sheets (optical sheet 207A and optical sheet 207B) for converting the diffusion characteristics in the vertical and horizontal directions (not shown in the front-rear direction of the figure) of the drawing are used on the light-emitting side of the light from the collimator 18, and the light from the collimator 18 is made to enter between the two optical sheets (diffusion sheets).

[0171] Note that the above optical sheet may be a single sheet instead of two sheets. In the case of a single-sheet configuration, the vertical and horizontal diffusion characteristics are adjusted by the fine shapes of the front and back surfaces of the single optical sheet. Also, a plurality of diffusion sheets may be used to share the functions. Here, in the example of FIG. 10, regarding the reflection and diffusion characteristics due to the front and back surface shapes of the optical sheet 207A and the optical sheet 207B, it is advisable to perform an optimal design using the number of LEDs, the divergence angle from the LED substrate (optical element) 102, and the optical specifications of the collimator 18 as design parameters so that the surface density of the light beam emitted from the liquid crystal display panel 11 becomes uniform. That is, the diffusion characteristics are adjusted by the surface shapes of a plurality of diffusion sheets instead of the light guide.

[0172] In the example of FIG. 10, the polarization conversion is performed in the same manner as in Example 3 of the display device described above. That is, in the example of FIG. 10, the reflective polarizing plate 49 may be configured to have the characteristic of reflecting S-polarized light (transmitting P-polarized light). In that case, among the light emitted from the LED which is the light source, the P-polarized light is transmitted, and the transmitted light enters the liquid crystal display panel 11. Among the light emitted from the LED which is the light source, the S-polarized light is reflected, and the reflected light passes through the retardation plate 270 shown in FIG. 10. The light that has passed through the retardation plate 270 is reflected by the reflector 271. The light reflected by the reflector 271 is converted into P-polarized light by passing through the retardation plate 270 again. The polarization-converted light passes through the reflective polarizing plate 49 and enters the liquid crystal display panel 11.

[0173] Note that the quarter-wave plate 270, which is the phase difference plate in Fig. 10, does not necessarily need to have a phase difference of λ / 4 with respect to the polarized light incident perpendicularly to the quarter-wave plate 270. In the configuration of Fig. 10, any phase difference plate that changes the phase by 90° (λ / 2) when the polarized light passes through it twice is acceptable. The thickness of the phase difference plate may be adjusted according to the incident angle distribution of the polarized light. Also, in Fig. 10, regarding the polarization design related to polarization conversion, the polarization state may be configured in the reverse manner (reversing the S-polarization and P-polarization) from the above description.

[0174] The light emitted from the liquid crystal display panel 11 has similar diffusion characteristics in both the horizontal direction of the screen (displayed on the X-axis in Fig. 12(a)) and the vertical direction of the screen (displayed on the Y-axis in Fig. 12(b)) in a general TV application device. In contrast, for the diffusion characteristics of the light beam emitted from the liquid crystal display panel of this embodiment, for example, as shown in Example 1 of Fig. 12, when the viewing angle at which the luminance becomes 50% of the front view (angle 0 degrees) is set to 13 degrees, it becomes 1 / 5 compared to 62 degrees of a general TV application device. Similarly, for the viewing angle in the vertical direction, the reflection angle of the reflective light guide and the area of the reflection surface, etc. are optimized so that the upper viewing angle is suppressed to about 1 / 3 of the lower viewing angle with upper and lower non-uniformity. As a result, compared with a conventional liquid crystal TV, the amount of video light directed toward the monitoring direction is significantly improved, and the luminance becomes 50 times or more.

[0175] Furthermore, considering the viewing angle characteristics shown in Example 2 of Fig. 12, when the viewing angle at which the luminance becomes 50% of the front view (angle 0 degrees) is set to 5 degrees, it becomes 1 / 12 compared to 62 degrees of a general TV application device. Similarly, for the viewing angle in the vertical direction, the reflection angle of the reflective light guide and the area of the reflection surface, etc. are optimized so that the viewing angle is suppressed to about 1 / 12 of a general TV application device with upper and lower uniformity. As a result, compared with a conventional liquid crystal TV, the amount of video light directed toward the monitoring direction is significantly improved, and the luminance becomes 100 times or more.

[0176] As described above, by using the viewing angle as the included angle, the amount of light beam directed toward the monitoring direction can be concentrated, so that the light utilization efficiency is greatly improved. As a result, even when using a liquid crystal display panel for general TV applications, by controlling the light diffusion characteristics of the light source device, it is possible to achieve a significant increase in brightness with the same power consumption, and it can be made into a video display device corresponding to an information display system for bright outdoors.

[0177] When using a large liquid crystal display panel, the light around the screen is directed inward so that it heads toward the viewer when the viewer is facing the center of the screen, thereby improving the overall uniformity of the screen brightness. FIG. 11 shows the convergence angles of the long side and the short side of the panel when the distance L from the viewer to the panel and the panel size (screen ratio 16:10) are used as parameters. When monitoring with the screen in portrait orientation, the convergence angle can be set according to the short side. For example, when using a 22-inch panel in portrait orientation and the monitoring distance is 0.8 m, if the convergence angle is set to 10 degrees, the video light from the four corners of the screen can be effectively directed toward the viewer.

[0178] Similarly, when monitoring with a 15-inch panel in portrait orientation and the monitoring distance is 0.8 m, if the convergence angle is set to 7 degrees, the video light from the four corners of the screen can be effectively directed toward the viewer. As described above, by directing the video light around the screen to the viewer who is in the optimal position for monitoring the center of the screen according to the size of the liquid crystal display panel and whether it is used in portrait or landscape orientation, the overall uniformity of the screen brightness can be improved.

[0179] As a basic configuration, as shown in FIG. 9, a light beam with an included angle directivity characteristic is incident on the liquid crystal display panel 11 by a light source device, and the luminance is modulated according to the video signal, so that the video information displayed on the screen of the liquid crystal display panel 11 and the spatial floating image obtained by reflecting with the retroreflective sheet are displayed outdoors or indoors through the transparent member 100.

[0180] By using the display device and the light source device according to an embodiment of the present invention described above, it is possible to realize a spatial floating image display device with higher light utilization efficiency.

[0181] <Example of Video Display Processing in Spatial Floating Image Display Device> Next, an example of a problem solved by the image processing of this embodiment will be described with reference to FIG. 13A. In the spatial floating image display device 1000, when the back side of the spatial floating image 3 as viewed by the user is inside the housing of the spatial floating image display device 1000 and is sufficiently dark, the user visually recognizes that the background of the spatial floating image 3 is black.

[0182] Here, an example of displaying the character "Panda" 1525 in the spatial floating image 3 will be described with reference to FIG. 13A. First, the video control unit 1160 in FIG. 3 distinguishes and recognizes the pixel region for drawing the image of the character "Panda" 1525 and the image including the transparent information region 1520 which is the background image, as shown in FIG. 13A(1).

[0183] A method of distinguishing and recognizing the character image and the background image is, for example, in the image processing of the video control unit 1160, configuring the background image layer and the layer of the character image in front of the background image layer to be processed as separate layers, and distinguishing and recognizing the character image and the background image according to the superimposition relationship when these layers are synthesized.

[0184] Here, the video control unit 1160 recognizes, as information different from the black and transparent information pixels, the pixels for drawing objects such as character images. However, it is assumed that both the black and transparent information pixels of the pixels for drawing objects have a luminance of 0. In this case, when displaying the spatial floating video 3, there is no difference in luminance between the pixels for drawing black in the image of the character "panda" 1525 and the pixels in the transparent information area 1520 which is the background image. Therefore, in the spatial floating video 3, as shown in FIG. 13A(2), neither the pixels for drawing black in the image of the character "panda" 1525 nor the pixels in the transparent information area 1520 have luminance, and it is visually recognized by the user as an optically identical black space. That is, the portion for drawing black in the image of the object, the character "panda" 1525, melts into the background, and only the portion that is not black in the character "panda" 1525 is recognized as a video floating in the display area of the spatial floating video 3.

[0185] An example of the image processing in this embodiment will be described with reference to FIG. 13B. FIG. 13B is a diagram for explaining an example of image processing that more preferably solves the problem that the black image area of the object melts into the background, which was described with reference to FIG. 13A. In FIGS. 13B(1) and (2), the display state of the spatial floating video 3 is shown on the upper side, and the input / output characteristics of the image processing of the image of the object are shown on the lower side. Note that the image of the object (character "panda" 1525) and the corresponding data may be read from the storage unit 1170 or the memory 1109 in FIG. 3. Alternatively, it may be input from the video signal input unit 1131. Alternatively, it may be acquired via the communication unit 1132.

[0186] Here, in the state of FIG. 13B(1), the input / output characteristics of the image processing of the image of the object are in a linear state without being particularly adjusted. In this case, it is the same display state as in FIG. 13A(2), and the black image area of the object melts into the background. On the other hand, in FIG. 13B(2), the video control unit 1160 in this embodiment adjusts the input / output characteristics of the image processing for the image of the object (character "panda" 1525) to be as shown in the input / output characteristics in the lower part.

[0187] That is, the video control unit 1160 performs image processing with input-output characteristics that have the property of converting the pixels of the input image into output pixels with increased luminance values for the pixels in the low-luminance region of the image of the object (character "Panda" 1525). After the image of the object (character "Panda" 1525) has undergone the image processing with the said input-output characteristics, the video including the image of the object (character "Panda" 1525) is input to the display device 1 and displayed. Then, as shown in the upper part of FIG. 13B(2), the display state of the floating-in-air video 3 is such that the luminance of the pixel region that draws black in the image of the character "Panda" 1525 increases. As a result, among the regions that draw the image of the character "Panda" 1525, the regions that draw black can also be distinguished from the black of the background without blending in and recognized by the user, making it possible to more suitably display the object.

[0188] That is, by using the image processing of FIG. 13B(2), the region where the image of the character "Panda" 1525, which is the object, is displayed can be recognized separately from the black of the background inside the housing of the floating-in-air video display device 1000 through the window, improving the visibility of the object. Therefore, for example, before the said image processing (that is, when the image of the object and the corresponding data are read from the storage unit 1170 or the memory 1109 in FIG. 3, or when the image of the object is input from the video signal input unit 1131, or when the data of the object is acquired via the communication unit 1132, etc.), even if the object includes pixels with a luminance value of 0 among the pixels that make up the object, after being converted into an object with increased luminance values of the pixels in the low-luminance region by the image processing with the said input-output characteristics by the video control unit 1160, it is displayed on the display device 1 and converted into the floating-in-air video 3 by the optical system of the floating-in-air video display device 1000.

[0189] That is, the pixels constituting the object after the image processing of the input / output characteristics are converted to a state where pixels with a luminance value of 0 are not included, and then displayed on the display device 1, and are converted into the spatial floating image 3 by the optical system of the spatial floating image display device 1000.

[0190] In the image processing of FIG. 13B(2), for example, in the image processing of the video control unit 1160, as a method of performing the image processing of the input / output characteristics of FIG. 13B(2) only on the area of the image of the object (character "panda" 1525), the background image layer and the layer of the character image in front of the background image layer are configured to be processed as separate layers so that the image processing of the input / output characteristics of FIG. 13B(2) can be performed on the layer of the character image, and the image processing is not performed on the background image layer.

[0191] After that, if these layers are combined, as shown in FIG. 13B(2), only the character image will be subjected to the image processing with the characteristic of lifting the low-luminance area of the input image. As another method, it may be configured to perform the image processing of the input / output characteristics of FIG. 13B(2) only on the area of the character image after the layer of the character image and the background image layer are combined.

[0192] Also, the input / output video characteristics used in the video processing for lifting the low-luminance area of the input / output characteristics with respect to the input video are not limited to the example of FIG. 13B(2). Any video processing that lifts the low luminance may be used, such as so-called brightness adjustment. Or, video processing for improving visibility may be performed by controlling the gain that changes the weighting of the retinex processing as disclosed in International Publication No. 2014 / 162533.

[0193] According to the image processing of FIG. 13B(2) described above, regarding the area where black is drawn among the areas for drawing images such as characters and objects, it is possible to make the user recognize it without melting into the black of the background, and a more suitable display can be realized.

[0194] In the examples of FIGS. 13A and 13B, the problem and more suitable image processing are described by taking as an example a spatial floating image display device in which the background appears black (for example, the spatial floating image display device 1000 in FIGS. 4A to 4G, or the spatial floating image display device 1000 in the state where the rear window is shielded from light in FIGS. 4I and 4J). However, the said image processing is also effective in devices other than these spatial floating image display devices.

[0195] Specifically, in the spatial floating image display device 1000 of FIG. 4H or the spatial floating image display device 1000 in the state where the rear window is not shielded from light in FIGS. 4I and 4J, the background of the spatial floating image 3 is not black, but is the scenery behind the spatial floating image display device 1000 through the window. Also in this case, the problems described in FIGS. 13A and 13B exist in the same way.

[0196] That is, the portion of the image of the character "panda" 1525 that is drawn in black will blend into the scenery behind the spatial floating image display device 1000 through the window. Also in this case, by using the image processing of FIG. 13B(2), the portion of the image of the character "panda" 1525 that is drawn in black can be recognized separately from the scenery behind the spatial floating image display device 1000 through the window, and the visibility of the object is improved.

[0197] That is, by using the image processing of FIG. 13B(2), the area for displaying the image of the character "panda" 1525 that is the object can be recognized separately from the scenery behind the spatial floating image display device 1000 through the window, and it becomes possible to more preferably recognize that the character "panda" that is the object is in front of the said scenery, and the visibility of the object is improved.

[0198] Also, in the spatial floating image display device 1000 of FIGS. 4K, 4L, and 4M, as described above, when another image (such as the image of the transmissive self-luminous image display device 1650 or the image of the second display device 1680) is displayed at a position with a different depth from the spatial floating image 3, the background of the spatial floating image 3 is not black but becomes the other image. Also in this case, the problems described with reference to FIGS. 13A and 13B similarly exist.

[0199] That is, the portions of the image of the character "panda" 1525 that are drawn in black, which is the object, will blend into the other image displayed at a position with a different depth from the spatial floating image 3. Also in this case, by using the image processing of FIG. 13B(2), the portions of the image of the character "panda" 1525 that are drawn in black can be recognized separately from the other image, and the visibility of the object is improved.

[0200] That is, by using the image processing of FIG. 13B(2), the area where the image of the character "panda" 1525, which is the object, is displayed can be recognized separately from the other image, and it becomes possible to more preferably recognize that the character "panda" 1525, which is the object, is in front of the other image, and the visibility of the object is improved.

[0201] An example of the video display process of this embodiment will be described with reference to FIG. 13C. FIG. 13C is an example of video display in which the spatial floating image 3 and a second image 2050, which is another image, are simultaneously displayed among the examples of video display of this embodiment. The second image 2050 may correspond to the display image of the transmissive self-luminous image display device 1650 of FIG. 4K or FIG. 4L. Also, the second image 2050 may correspond to the display image of the second display device 1680 of FIG. 4M.

[0202] That is, an example of the video display in FIG. 13C shows a specific example of the video display example of the spatial floating video display device 1000 in FIGS. 4K, 4L, and 4M. In the example of this figure, a bear character is displayed in the spatial floating video 3. The area other than the bear character in the spatial floating video 3 is displayed in black and becomes transparent as the spatial floating video. Also, the second image 2050 is a background image depicting a plain, mountains, and the sun.

[0203] Here, in FIG. 13C, the spatial floating video 3 and the second image 2050 are displayed at different depths. By the user 230 visually recognizing the two videos of the spatial floating video 3 and the second image 2050 in the line-of-sight direction of the arrow 2040, the user 230 can visually recognize the videos in a state where the two videos overlap. Specifically, the bear character of the spatial floating video 3 will appear superimposed in front of the background of the plain, mountains, and sun drawn in the second image 2050.

[0204] Here, since the spatial floating video 3 forms a real image in the air, when the user 230 slightly moves the viewing point, the user 230 can recognize the depths of the spatial floating video 3 and the second image 2050 due to the parallax. Therefore, the user 230 can obtain a stronger sense of spatial floating for the spatial floating video 3 while visually recognizing the two videos in an overlapping state.

[0205] An example of the video display process of this embodiment will be described with reference to FIG. 13D. FIG. 13D(1) is a view of the spatial floating video 3 in the example of the video display of this embodiment in FIG. 13C as seen from the line-of-sight direction of the user 230. Here, a bear character is displayed in the spatial floating video 3. The area other than the bear character in the spatial floating video 3 is displayed in black and becomes transparent as the spatial floating video.

[0206] FIG. 13D(2) is a view of the second image 2050 in the example of the video display of this embodiment in FIG. 13C as seen from the line-of-sight direction of the user 230. In the example of this figure, the second image 2050 is a background image depicting a plain, mountains, and the sun.

[0207] FIG. 13D(3) is a diagram showing a state in which, among the examples of video display in the present embodiment of FIG. 13C, the second image 2050 and the spatially floating video 3 appear to overlap in the line-of-sight direction of the user 230. Specifically, in front of the background of the plain, mountains, and sun drawn in the second image 2050, the bear character of the spatially floating video 3 appears to overlap.

[0208] Here, when the spatially floating video 3 and the second image 2050 are displayed simultaneously, in order to more preferably ensure the visibility of the spatially floating video 3, it is desirable to pay attention to the balance of the brightness of the two videos. If the second image 2050 is too bright compared to the brightness of the spatially floating video 3, the displayed video of the spatially floating video 3 will become transparent, and the second image 2050 as the background will be strongly visible through it.

[0209] Therefore, at least, the brightness per unit area of the spatially floating video 3 at the display position of the spatially floating video 3 should be greater than the brightness per unit area of the video light reaching the display position of the spatially floating video 3 from the second image 2050. The output of the light source of the spatially floating video 3, the display video brightness of the display device 1, the output of the light source of the display device for displaying the second image 2050, and the display video brightness of the said display device may be set.

[0210] Note that since this condition only needs to be satisfied when the spatially floating video 3 and the second image 2050 are displayed simultaneously, when switching from the first display mode in which only the second image 2050 is displayed without displaying the spatially floating video 3 to the second display mode in which the spatially floating video 3 and the second image 2050 are displayed simultaneously, the output of the light source of the display device for displaying the second image 2050 and / or the display video brightness of the said display device may be lowered to reduce the brightness of the second image 2050. These controls may be realized by the control unit 1110 in FIG. 3 controlling the display device 1 and the display device for displaying the second image 2050 (the transmissive self-emitting video display device 1650 in FIG. 4K or FIG. 4L or the second display device 1680 in FIG. 4M).

[0211] In addition, when performing control to reduce the brightness of the second image 2050 in the switching from the above-described first display mode to the above-described second display mode, the brightness may be uniformly reduced for the entire screen of the second image 2050. Or, without uniformly reducing the brightness for the entire screen of the second image 2050, the portion where the object is displayed in the spatial floating image 3 is set to the state with the highest brightness reduction effect, and the periphery thereof may gradually reduce the brightness reduction effect step by step. That is, as long as the brightness reduction of the second image 2050 is realized only for the portion where the spatial floating image 3 is superimposed on and visually recognized by the second image 2050, ensuring the visibility of the spatial floating image 3 is sufficient.

[0212] Here, since the spatial floating image 3 and the second image 2050 are displayed at positions with different depths, when the user 230 slightly changes the viewing point, due to the parallax, the superimposition position of the spatial floating image 3 with respect to the second image 2050 changes. Therefore, in the switching from the above-described first display mode to the above-described second display mode, when reducing the brightness non-uniformly for the entire screen of the second image 2050, it is not desirable to sharply reduce the brightness based on the outline of the object displayed in the spatial floating image 3. It is desirable to perform gradation processing of the brightness reduction effect, where the brightness reduction effect gradually changes according to the position as described above.

[0213] In the spatial floating image display device 1000 where the position of the object displayed in the spatial floating image 3 is approximately at the center of the spatial floating image 3, the position with the highest brightness reduction effect in the gradation processing of the brightness reduction effect may be set to the center position of the spatial floating image 3.

[0214] According to the video display processing of the present embodiment described above, the user 230 can more suitably visually recognize the spatial floating image 3 and the second image 2050.

[0215] In addition, when displaying the floating image 3 in space, it may be controlled so as not to display the second image 2050. Since the visibility of the floating image 3 in space is enhanced when the second image 2050 is not displayed, it is suitable for a floating image display device 1000 in space for applications where the user must surely visually recognize the floating image 3 in space when the floating image 3 in space is displayed.

[0216] <Example 2> As a second embodiment of the present invention, an example of another configuration example of the floating image display device in space will be described. Note that the floating image display device according to the present embodiment is obtained by changing the optical system stored in the floating image display device described in the first embodiment to the optical system shown in Fig. 14(1) or Fig. 14(2). In this embodiment, the differences from the first embodiment will be described, and repeated descriptions of the same configurations as in the first embodiment will be omitted. Note that in the following description of this embodiment, a predetermined polarization and the other polarization are polarizations of polarization waves having a phase difference of 90° from each other.

[0217] Fig. 14(1) is an example of the optical system and the optical path according to the present embodiment. The optical system shown in Fig. 14(1) is configured such that in the optical system of Fig. 2C, the display device 1 is brought closer by the polarization separation member 101B, making the entire optical system more compact. In Fig. 14(1), repeated detailed descriptions of the configurations denoted by the same reference numerals as in Fig. 2C are omitted.

[0218] In Fig. 14(1), similar to Fig. 2C, the video light of a predetermined polarization (P polarization in the figure) emitted from the display device 1 travels in the vertical direction from the video display surface of the display device 1. Here, similar to Fig. 2C, the polarization separation member 101B selectively transmits a predetermined polarization (P polarization in the figure) emitted from the display device 1 and reflects the other polarization (S polarization in the figure).

[0219] Therefore, the video light of a predetermined polarization (P-polarization in the figure) that travels vertically from the video display surface of the display device 1 passes through the polarization separation member 101B and reaches the retroreflective plate 2 to which the λ / 4 plate 21 is attached. The video light that is retroreflectively reflected by the retroreflective plate 2 and travels again toward the polarization separation member 101B has passed through the λ / 4 plate 21 twice, and thus is converted from the predetermined polarization (P-polarization in the figure) at the time of emission from the display device 1 to the other polarization (S-polarization in the figure). Since the video light that travels again toward the polarization separation member 101B is the other polarization (S-polarization in the figure), it is reflected by the polarization separation member 101B toward the position where the user should be. The traveling direction of the video reflected by the polarization separation member 101B is determined based on the angle at which the polarization separation member 101B is arranged.

[0220] In the example of FIG. 14(1), the video light that travels toward the polarization separation member 101B is reflected at a right angle by the polarization separation member 101B and travels as shown in the figure. The video light reflected by the polarization separation member 101B forms a spatial floating image 3A. The spatial floating image 3A can be suitably viewed by the user from the direction of arrow A.

[0221] Here, due to the characteristics of the retroreflective reflection by the retroreflective plate 2, the optical path length from when the video light emitted from the display device 1 reaches the retroreflective plate 2 and the optical path length from when the video light emitted from the retroreflective plate 2 reaches the formation position of the spatial floating image 3A are in an equal relationship. Due to this relationship, the formation position of the spatial floating image 3A in the traveling direction of the video light reflected by the polarization separation member 101B is determined.

[0222] In the example of FIG. 14(1), the display device 1, the polarization separation member 101B, and the retroreflective plate 2 are arranged so as to be closer than in the example of FIG. 2C. Thereby, it is realized that the entire optical system is configured more compactly. However, the amount by which the spatial floating image 3A protrudes from the optical system of FIG. 14(1) is not so large. For example, as one index of the amount by which the spatial floating image 3A protrudes from the optical system, the distance from the position where the light ray at the center portion of the video light is reflected by the polarization separation member 101B to the position where the video light forms the spatial floating image 3A is shown in the figure (L1 in the example of FIG. 14(1)).

[0223] Regarding the polarization design in the optical system of FIG. 14(1), the characteristics of P-polarized light and S-polarized light may be interchanged. Specifically, a predetermined polarization of the video light emitted from the display device 1 may be set as S-polarized light, and regarding the reflection characteristics of the polarization separation member 101B, the characteristics of P-polarized light and S-polarized light may be interchanged. In this case, although both the P-polarized light and S-polarized light shown in the figure are reversed, the optical design such as the optical path can be realized in exactly the same way.

[0224] Next, FIG. 14(2) shows another example of the optical system and the optical path according to this embodiment. The optical system of FIG. 14(2) modifies the configuration in the optical system of FIG. 14(1) in order to make the amount of the spatial floating image jumping out from the optical system larger while realizing the same compactness as the optical system of FIG. 14(1). In FIG. 14(2), for the configurations denoted by the same reference numerals as in FIG. 14(1), repeated detailed descriptions are omitted.

[0225] In FIG. 14(2), similar to FIG. 14(1), the video light of a predetermined polarization (P-polarized light in the figure) emitted from the display device 1 travels in the vertical direction from the video display surface of the display device 1. Here, the polarization characteristics of the polarization separation member 101B are arranged 90 degrees differently from those in FIG. 14(1). The video light of a predetermined polarization (P-polarized light in the figure) that has traveled in the vertical direction from the video display surface of the display device 1 passes through the polarization separation member 101B.

[0226] Here, different from FIG. 14(1), instead of the retroreflector 2 with the λ / 4 plate 21 attached thereto, a specular reflector 4 with the λ / 4 plate 21B attached thereto is arranged at the position where the video light passes through the polarization separation member 101B. Here, the reflection in the specular reflector 4 is specular reflection (also called regular reflection), not retroreflection.

[0227] Therefore, the video light that has passed through the polarization separation member 101B is specularly reflected by the specular reflection plate 4 to which the λ / 4 plate 21B is attached. The video light that is specularly reflected by the specular reflection plate 4 and travels again toward the polarization separation member 101B has been converted from a predetermined polarization (P polarization in the figure) at the time of emission from the display device 1 to the other polarization (S polarization in the figure) by passing through the λ / 4 plate 21 twice. Since the video light that has traveled again toward the polarization separation member 101B is the other polarization (S polarization in the figure), it is reflected by the polarization separation member 101B.

[0228] Here, since the orientation of the polarization separation member 101B in Fig. 14(2) is different from that in Fig. 14(1), the video light reflected by the polarization separation member 101B travels in the direction opposite to the position where the user should be. At the destination where the video light reflected by the polarization separation member 101B travels, the retroreflective plate 2 to which the λ / 4 plate 21C is attached is arranged. The video light is retroreflectively reflected by the retroreflective plate 2. The video light that is retroreflectively reflected by the retroreflective plate 2 and travels again toward the polarization separation member 101B has been converted from the other polarization (S polarization in the figure) to the predetermined polarization (P polarization in the figure) again by passing through the λ / 4 plate 21C twice.

[0229] Since the video light that has traveled again toward the polarization separation member 101B is the predetermined polarization (P polarization in the figure), it passes through the polarization separation member 101B and travels directly toward the position where the user should be. The video light that has passed through the polarization separation member 101B forms the spatial floating image 3B. The spatial floating image 3B can be preferably visually recognized by the user from the direction of arrow A.

[0230] Here, also in Fig. 14(2), similar to Fig. 14(1), due to the characteristics of the retroreflective reflection by the retroreflective plate 2, the optical path length from the display device 1 to the arrival of the video light at the retroreflective plate 2 and the optical path length from the emission of the video light from the retroreflective plate 2 to the arrival at the formation position of the spatial floating image 3B are in an equal relationship. Based on this relationship, the formation position of the spatial floating image 3B in the traveling direction of the video light that has passed through the polarization separation member 101B is determined.

[0231] In FIG. 14(2), the optical path length from the display device 1 to the point where the video light emitted from the display device 1 reaches the retroreflector 2 is longer than the optical path length from the display device 1 to the point where the video light emitted from the display device 1 reaches the retroreflector 2 in FIG. 14(1). This is because in the optical system of FIG. 14(2), an optical path that travels back and forth between the polarization separation member 101B and the specular reflector 4, which does not exist in the optical system of FIG. 14(1), is added to the optical path length from the display device 1 to the point where the video light reaches the retroreflector 2.

[0232] As a result, in the optical system of FIG. 14(2), the distance (L2 in the example of FIG. 14(2)) from the position where the light rays of the central portion of the video light pass through the polarization separation member 101B to the position where the video light forms the spatial floating image 3B is significantly longer than the distance (L1 in the example of FIG. 14(1)) from the position where the light rays of the central portion of the video light are reflected by the polarization separation member 101B to the position where the video light forms the spatial floating image 3A in the optical system of FIG. 14(1).

[0233] Regarding the polarization design in the optical system of FIG. 14(2), the characteristics of P-polarized light and S-polarized light may be interchanged. Specifically, a predetermined polarization of the video light emitted from the display device 1 may be set as S-polarized light, and the reflection characteristics of the polarization separation member 101B may have the characteristics of P-polarized light and S-polarized light interchanged. In this case, although both the illustrated P-polarized light and S-polarized light are reversed, the optical design such as the optical path can be realized in exactly the same way.

[0234] According to the optical systems of FIGS. 14(1) and 14(2) in the second embodiment of the present invention described above, a more compact optical system can be realized. In particular, according to the optical system of FIG. 14(2), it is possible to make the amount by which the spatial floating image protrudes from the optical system larger while having a more compact optical system.

[0235] When incorporating the optical system of Fig. 14(1) or Fig. 14(2) into the spatial floating image display device, it can be realized by replacing the optical system in the spatial floating image display device described in Example 1 with the optical system of Fig. 14(1) or Fig. 14(2). Specifically, the optical system of Fig. 14(1) may be replaced with the optical system of the spatial floating image display device in Figs. 4E, 4F, 4G, 4H, 4I, 4J, 4K, 4L, or 4M. In this case, since the optical system becomes more compact, it is possible to make the housing of the spatial floating image display device in each figure smaller.

[0236] Specifically, the optical system of Fig. 14(2) may also be replaced with the optical system of the spatial floating image display device in Figs. 4E, 4F, 4G, 4K, or 4L. In this case, it is possible to make the amount by which the spatial floating image protrudes from the optical system larger. Also, since the optical system becomes more compact, it is possible to make the housing of the spatial floating image display device in each figure smaller.

[0237] <Example 3>[Technology for Displaying Multi-Viewpoint Video as a Floating Image in the Air] Fig. 15(A) shows the main configuration of a spatial floating image display device 1000 according to an embodiment capable of displaying a multi-viewpoint video as a floating image in the air. The spatial floating image display device 1000 shown in Fig. 15(A) is composed of an optical system using the video display device 1, the retroreflective plate 2, and the polarization separation member 101 shown in Fig. 4D. Furthermore, it is different in configuration from the spatial floating image display device 1000 shown in Fig. 4D in that a lenticular lens 1103 is provided on the video light emission side of the video display device 1.

[0238] As shown in Fig. 15(A), as shown in Fig. 15(B), the lenticular lens 1103 is arranged parallel or substantially parallel to the light-emitting surface of the liquid crystal display panel 11 and is arranged on the video light side emitted from the surface of the liquid crystal display panel 11. At this time, the lenticular lens 1103 is arranged at a position a predetermined distance away from the surface of the liquid crystal display panel 11. Further, the plurality of semi-cylinders (semi-cylindrical lenses) of the lenticular lens 1103 extend in the vertical direction, that is, the Y-axis direction, and are arranged side by side in the horizontal direction, that is, the X-axis direction. Note that the above coordinate system (X, Y, Z) is common in Figs. 15(A) and 15(B).

[0239] Also, as shown in Fig. 15(A), an absorption type polarizing plate 12 may be provided above the lenticular lens 1103. The video light emitted from the display device 1 passes through the lenticular lens 1103 and the absorption type polarizing plate 12 and goes toward the retroreflective plate 2, but a part of it is reflected by the polarization separation member 101 (retroreflected light), and this retroreflected light may be visually recognized as a ghost image. Therefore, by absorbing this retroreflected light with the absorption type polarizing plate 12, the above retroreflected light can be suppressed. Thereby, it is possible to prevent the image quality from deteriorating due to the ghost image of the spatially floating image.

[0240] Note that in the third embodiment, as an example of the spatial floating video display device 1000 capable of displaying a multi-viewpoint video as a spatially floating image, the configuration shown in Fig. 4D will be described as a basis. However, as long as the lenticular lens 1103 is provided on the video light emission side of the video display device 1, any of the configurations shown in Figs. 4A to 4O may be used as a basis. Further, in the configurations shown in Figs. 4A to 4O, the retroreflective plate 2 is more widely referred to as a retroreflective member.

[0241] FIG. 15(B) is an enlarged view of the lenticular lens 1103 disposed on the video light emission side of the video display device 1 shown in FIG. 15(A), that is, on the video light emission side of the liquid crystal display panel 11. Further, the spatial floating video display device 1 shown in FIG. 15(A) is a system suitable for a user (viewer) 203 to observe the spatial floating video 3 from an obliquely upper direction. In the coordinate system (X, Y, Z) in FIG. 15(A), the housing 1190 of the spatial floating video display device 1000 is disposed on the horizontal plane (X-Y plane), and the spatial floating video 3 is formed to be slightly inclined in the front-rear direction (Y direction) with respect to the vertical direction (Z direction). When visually recognizing the surface of the spatial floating video 3 directly from the viewpoint E of the user, the user can preferably visually recognize the spatial floating video 3 with a line of sight slightly obliquely downward in the Y direction along the optical axis J2 with respect to the surface of the spatial floating video 3 as shown in the drawing. Hereinafter, the user (viewer) may also be referred to as an observer.

[0242] Next, as shown in FIG. 15(B), the lenticular lens 1103 is disposed parallel or substantially parallel to the light emission surface of the liquid crystal display panel 11 and on the video light side emitted from the surface of the liquid crystal display panel 11. At this time, the lenticular lens 1103 is disposed at a position separated from the surface of the liquid crystal display panel 11 by a predetermined distance. Further, a plurality of semi-cylinders (semi-cylindrical lenses) of the lenticular lens 1103 extend in the vertical direction, that is, the Y-axis direction, and are arranged side by side in the horizontal direction, that is, the X-axis direction. Note that the above coordinate system (X, Y, Z) is common to FIGS. 15(A) and 15(B).

[0243] In the housing 1190, the video display device 1, the retroreflective plate 2, etc. are arranged in a predetermined positional relationship. Above the housing 1190 (X-Z plane), there is an opening, and a transparent member 100 is attached to this opening so that dust, dirt, etc. do not enter the inside of the housing. Further, the optical axis J1 of the video display device 1 faces the Z-axis direction, and the polarization separation member 101 is disposed at a predetermined angle with respect to the optical axis J1. Note that the polarization separation member is generally also known by the name of a polarization beam splitter and is formed of a reflective polarizing plate, a metal multilayer film that reflects a specific polarization wave, or the like.

[0244] On the one hand, the video display device 1 includes a liquid crystal display panel 11 as a video display element and a light source device 13 that generates light of a specific polarization having a diffusion characteristic with a sandwiching angle. The liquid crystal display panel 11 can be applied to small ones with a screen size of about 5 inches to large ones exceeding 80 inches, and a panel of a size selected from these is used according to the application.

[0245] The video light from the liquid crystal display panel 11 is emitted toward the retroreflector 2 (which may also be described as a retroreflective portion or a retroreflective member) on the optical axis J1. Light from the light source device 13 with a narrow divergence angle is incident on the liquid crystal display panel 11. The video light with the narrow divergence angle is incident on the retroreflector 2 from below in the Z direction along the optical axis J1. At this time, the video light from the liquid crystal display panel 11 passes through the polarization separation member 101 and heads toward the retroreflector 2. Next, the video light that has passed through the polarization separation member 101 is retroreflected by the retroreflector 2, and the video light travels downward in the Z direction. Here, as is well known, the video light from the liquid crystal display panel 11 is of a specific polarization such as S polarization (an electromagnetic wave whose electric field component is perpendicular to the incident plane, S is an abbreviation for Senkrecht) or P polarization (an electromagnetic wave whose electric field component is parallel to the incident plane, P is an abbreviation for Parallel).

[0246] As shown in FIG. 15(A), a λ / 4 plate 21 is disposed on the surface of the retroreflector 2. Therefore, the video light (optical axis J1) retroreflected by the retroreflector 2 passes through the λ / 4 plate 21 twice, so the polarization changes. Specifically, when the video light incident on the retroreflector 2 is S polarization, it changes to P polarization, and conversely, when the video light incident on the retroreflector 2 is P polarization, it changes to S polarization. Therefore, the video light (optical axis J1) retroreflected by the retroreflector 2 is reflected by the polarization separation member 101 without passing through the polarization separation member 101. As a result, video light with a narrow divergence angle is generated in the direction of the optical axis J2, and a spatial floating image 3, which is a real image, is formed at a predetermined position outside the housing 1190 through the opening by the video light (optical axis J2).

[0247] Furthermore, in this configuration, a video light control sheet 334 (not shown in FIG. 15) may be provided on the emission side of the liquid crystal display panel 11 (directly below the lenticular lens 1103). In combination with the light source device 13 having a narrow divergence angle, the video light control sheet 334 can generate video light with an even narrower divergence angle and suppress the diffusion of the video light in unnecessary directions. Here, although the angle at which the video light spreads is expressed as the divergence angle, the divergence angle may also be referred to as the diffusion angle. The video light control sheet 334 will be described in detail later.

[0248] Also, in this embodiment, the air operation detection sensor 1351 described with reference to FIG. 2 is mounted at a predetermined position of the housing 1190. Thereby, a system can be configured such that a user can access and interact with the spatial floating image 3. The air operation detection sensor 1351 detects the state of an operation (air operation) on the spatial floating image 3 by a user's finger or the like.

[0249] In the above-described configuration shown in FIG. 15(A), a lenticular lens 1103 is disposed on the video light emission side (the position indicated by the diagonal lines) of the liquid crystal display panel 11. More specifically, the lenticular lens 1103 is disposed on the video light emission side of the liquid crystal display panel 11 so as to have the orientation shown in FIG. 15(B). On the surface of the lenticular lens 1103 (here, the x-y plane), semi-cylindrical lenses extending in the y direction (vertical direction) are arranged side by side as a plurality of semi-cylindrical lenses in the x direction (horizontal direction). The x direction corresponds to the horizontal direction within the screen of the display panel 11, and the y direction corresponds to the vertical direction within the screen of the display panel 11. With this configuration, as will be described later, when the user moves in the direction (x direction, X direction) in which the semi-cylindrical lenses forming the lenticular lens 1103 are arranged, the user can view different images (or videos) from their respective positions. That is, by displaying a parallax image as an image or a video, a motion parallax is generated, and the image or video displayed on the liquid crystal display panel 11 can be recognized as a stereoscopic image. The multi-viewpoint video and the motion parallax will be described later.

[0250] In FIG. 15(A), since the floating image 3 in space is a real image formed at a symmetric position of the liquid crystal display panel 11 with the polarization separation member 101 as the symmetry plane, the user can visually recognize the floating image 3 in space as a stereoscopic image with motion parallax. That is, according to the above configuration in which the lenticular lens 1103 is arranged, the floating image 3 in space can be displayed not simply as a two-dimensional image displayed on the liquid crystal display panel 11 but as a stereoscopic image with motion parallax. By visually recognizing the floating image in space as a stereoscopic image, that is, a three-dimensional image, the user can visually recognize a subject such as a human face as an image closer to the real thing compared to the case of a two-dimensional image. For this reason, compared with the conventional floating image display device, it is possible to visually recognize a more immersive floating image in space, which is suitable for various applications.

[0251] FIG. 16(A) is a diagram (schematic diagram) showing the principle for generating a multi-viewpoint image using the lenticular lens 1103 in this example (FIGS. 15(A) and (B)). Further, FIG. 16(B) is a schematic diagram of the lenticular lens 1103 viewed from obliquely above to more clearly show the configuration of the lenticular lens 1103. Here, the case of 9 viewpoints will be described as an example of the multi-viewpoint image, but the number of viewpoints is not limited to 9 viewpoints. As long as the number of viewpoints is 3 or more, the observer can recognize the multi-viewpoint image, that is, a stereoscopic image with motion parallax.

[0252] In FIG. 16(A), the pixels of the liquid crystal display panel 11 form a multi-viewpoint image of 9 viewpoints with 9 pixels indicated by numbers 1 to 9 as one group. In FIG. 16(A), the numbers of the pixels that can be visually recognized by the observer as an image or video are shown as 1 to 9. Hereinafter, the number of the pixels may sometimes be simply described as pixel 1 to pixel 9. In FIG. 16(B), the lenticular lens 1103 has a plurality of lenses (semicylindrical lenses) 1103a repeatedly arranged in the X direction. As shown in FIG. 16(A), one group consisting of 9 pixels is in a paired relationship with one semicylindrical lens 1103a existing directly above (vertically upper part) the pixel group constituting the one group.

[0253] Here, it is known that the distance between human eyes, that is, the interpupillary distance, is approximately constant. For example, the average interpupillary distance PD of Japanese people is about 64 mm. By setting the positions of the pixels reaching the observer's right eye (ER) and left eye (EL) via the lenticular lens 1103 to half of the distance between human eyes, that is, about 32 mm, light from different pixels reaches the observer's (user's) right eye and left eye as shown in Fig. 16(A). When the observer is present at the position shown in Fig. 16(A), light from the image displayed on pixel 6 reaches the observer's right eye, and light from the image (or video) displayed on pixel 4 reaches the observer's left eye.

[0254] Therefore, the observer will see images displayed on different pixels 1 to pixel 9 with the right eye and the left eye respectively. If images of the same subject, specifically a three-dimensional object or a person's face, etc., taken from different viewpoints are displayed on each pixel, a parallax will occur in both eyes of the observer. As a result, the observer can recognize the captured images as three-dimensional. As shown in Fig. 16(A), with the configuration of arranging the lenticular lens 1103 at a predetermined distance L1 from the light-emitting side of the liquid crystal display panel 11, light from different pixels (pixels 1 to pixel 9) reaches the observer's right eye and left eye, so the observer can recognize a three-dimensional image.

[0255] In the example of Fig. 16(A), light from the image displayed on pixel 6 reaches the observer's right eye, and light from the image displayed on pixel 4 reaches the observer's left eye. Here, the optical paths of the video light from pixel 4 to the observer's left eye EL are indicated by L1, L2, and L3, and the optical paths of the video light from pixel 6 to the observer's right eye ER are indicated by R1, R2, and R3. Also, as will be described later, the two pixels 6 and 4 correspond to video light obtained by photographing the same object (subject or object) from different angles. Therefore, the observer can recognize the subject as a three-dimensional image (or video).

[0256] Note that FIG. 16(A) is a diagram showing the principle for generating a multi-viewpoint image using the lenticular lens 1103, and is a schematic diagram. That is, although the inter-pupillary distance PD of the observer is about 64 mm, the relative relationships such as the distance from the position of the observer's eyes to the lenticular lens 1103, the width (pitch) of the lenticular lens 1103, the distance L1, and the size of the pixel 11 on the liquid crystal panel are not necessarily accurately drawn in FIG. 16(A). For example, as will be described later, the size (pitch) of one lenticular lens 1103 is about 430 μm as an example, the distance L1 is the focal length of the lenticular lens, and the focal length is about 700 μm as an example.

[0257] In the above configuration, when the observer (particularly, the positions of the right and left eyes) moves in the left-right direction (X direction), light from pixels (pixels 1 to 9) different from those before the movement reaches the right and left eyes of the observer. More specifically, in the case of FIG. 16(A), when the observer moves 1 pixel, that is, 32 mm to the right, light from the image displayed on pixel 7 reaches the right eye of the observer, and light from the image displayed on pixel 5 reaches the left eye of the observer. Therefore, as the observer moves (moves), light from pixels (pixels 1 to 9) different from those before the movement reaches the eyes of the observer. As a result, the observer can obtain an effect equivalent to seeing the same object (subject or object) from a different angle as the observer moves in the left-right direction, that is, motion parallax. In other words, with the configuration shown in FIG. 16(A), the observer can feel as if the angle of viewing the same object is changed as the observer moves in the left-right direction.

[0258] FIG. 17 is a schematic diagram showing an example of an apparatus for capturing an image that causes the above-described motion parallax, that is, a multi-viewpoint image. FIG. 17 shows a state in which a person as a subject 1500 (particularly, the face portion of the person) is captured from nine different viewpoints. More specifically, cameras No. 1 to No. 9 are used as nine cameras 1501, and as shown in FIG. 17, they are arranged at positions on a semi-circular circumference where the angles with respect to each other are shifted by a predetermined angle at a position at a predetermined distance from the subject 1500 and captured. In the present embodiment, cameras No. 1 to No. 9 are arranged at positions where the angles with respect to each other are shifted by 22.5 degrees at positions equidistant from the subject 1500, in other words, at nine positions where 180 degrees is divided into eight parts. When capturing a multi-viewpoint image, not limited to the example of FIG. 17, the number of cameras 1501 may be changed according to the number of viewpoints, and accordingly, the distance and angle from the subject 1500 may be changed.

[0259] At this time, when the subject 1500 is stationary, it is also possible to capture a multi-viewpoint image by moving one camera 1501 in order to the positions of cameras No. 1 to No. 9 and capturing. When the subject 1500 is moving, for example, the face of a person who is talking while moving their mouth while changing their expression, it is also possible to use nine cameras 1501, fix the camera 1501 at each position, and capture it as a video (in other words, a moving image).

[0260] The images 1502 (or videos) of each camera 1501 captured by the nine cameras 1501 as described above are assigned to and displayed on nine respective pixels 1401 of a video display unit, here, a liquid crystal display panel 11. As shown in FIG. 17, by displaying a video of one subject 1500 as images 1502 (or videos) captured from different angles, a multi-viewpoint image (or multi-viewpoint video) with motion parallax can be obtained. In the example shown in FIG. 17, the face portion of the person as the subject 1500 is captured at different angles by nine cameras No. 1 to No. 9, and the images 1502 captured by the nine cameras 1501 are assigned to and displayed on each pixel (pixel 1 to pixel 9) of the liquid crystal display panel 11.

[0261] As described above, by arranging the lenticular lens 1103 on the light-emitting side of the liquid crystal display panel 11 as shown in FIG. 16(A), a multi-viewpoint image (or video) with motion parallax can be obtained. As a method for obtaining a multi-viewpoint image (or video), it is not limited to the method using one or a plurality of cameras 1501 as described above, and a method of rendering a multi-viewpoint image (or video) by computer graphics (CG) may also be used. By generating CG by rendering, a large-scale imaging device using a plurality of cameras becomes unnecessary, and it is possible to obtain a multi-viewpoint image (or video) more simply, without the limitation of the number of viewpoints due to the number of cameras, and in a short time, which is preferable.

[0262] Next, FIGS. 18(A) and (B) are diagrams showing a multi-viewpoint video display device and an example of displaying a multi-viewpoint video. Here, the multi-viewpoint video display device refers to a display device having a configuration in which a lenticular lens 1103 is arranged on the video light-emitting side of a video display device 1 constituted by a liquid crystal display panel 11, a light source device 13, and the like. Specifically, the multi-viewpoint video display device includes a light source device 13, a liquid crystal display panel 11 which is a video display unit, and a lenticular lens 1103. The video display device 1 displays a video including at least three objects, and among the at least three objects, a plurality of videos obtained by fixing the position of an object or shifting it in the left-right direction (a predetermined direction) are displayed as multi-viewpoint images. That is, the video display device 1 displays a video including at least three objects, and among the at least three objects, the position of an arbitrary object (the first object) is fixed, and a plurality of images or videos obtained by shifting the positions of the objects other than the arbitrary object (the second object) in the left-right direction with respect to each other between different multi-viewpoint images are displayed as multi-viewpoint images.

[0263] Here, the left - right direction (predetermined direction) means the left - right direction (X - direction in Fig. 16(A)) with respect to the user's viewpoint, and corresponds to the direction in which a plurality of semi - cylindrical lenses 1103a in the lenticular lens 1103 are repeatedly arranged. In this case, the image - emitting surface of the liquid - crystal display panel 11, which is the image - display unit, and the incident surface of the lenticular lens 1103 are parallel. Also, the image - emitting surface of the liquid - crystal display panel 11, which is the image - display unit, and the incident surface of the lenticular lens 1103 are arranged with a predetermined distance L1 therebetween. In the present embodiment, based on the focal length unique to the lenticular lens 1103, the predetermined distance between the light - incident surface of the lenticular lens 1103 and the light - emitting surface of the liquid - crystal display panel 11 is adjusted and arranged. At this time, when the focal length of the lenticular lens 1103 is a relatively large value, the above - mentioned predetermined distance is increased, and conversely, when the focal length of the lenticular lens 1103 is a relatively small value, the above - mentioned predetermined distance is decreased. That is, the distance between the light - incident surface of the lenticular lens 1103 and the light - emitting surface of the liquid - crystal display panel 11, that is, the above - mentioned predetermined distance, is adjusted. Thereby, a suitable multi - viewpoint image without defocusing or the like can be displayed.

[0264] In Fig. 18, Fig. 18(A) shows a case where images 1502 taken by cameras 1501 (No. 1 to No. 9) are arranged in the shooting order with respect to the aforementioned pixels 1 to 9 of the liquid - crystal display panel 11. On the other hand, Fig. 19(B) shows a case where images 1502 taken by cameras 1501 (No. 9 to No. 1) are arranged in the order reverse to that of Fig. 18(A) with respect to pixels 1 to 9 of the liquid - crystal display panel 11. The differences in the effects of Figs. 18(A) and (B) are as follows. First, in Fig. 18(A), when a user moves from the left side to the right side with respect to the multi - viewpoint image display device, from the left side, an image of the subject (a person's face) seen from the left side can be observed, and from the right side, an image of the subject (a person's face) seen from the right side can be observed. That is, with the actual subject as the center, a subject similar to the case where the user observes from the left side or the right side of the subject can be observed.

[0265] On the contrary, in Fig. 18(B), which is the reverse of Fig. 18(A), when the user (observer) moves from the left side to the right side with respect to the multi-viewpoint video display device, from the left side, an image of the subject (a person's face) seen from the right side of Fig. 18(A) can be observed, and from the right side, an image of the subject (a person's face) seen from the left side of Fig. 18(A) can be observed. As a result, in Fig. 18(B), when looking at the subject (a person's face) from the user, no matter what position (relative angle) the user exists with respect to the subject, it can be felt that the person who is the subject is always looking at the user.

[0266] The viewing method of Fig. 18(B) described above, that is, the feature that the person who is the subject always seems to be looking at the user regardless of the position of the user, produces the effect that the person who is the subject always seems to be facing the user (himself / herself) and being talked to from the user's perspective. Such an effect is particularly suitable in a scene where the person who is the subject is a person who gives some guidance or explanation to the user (for example, a concierge) and the concierge gives some explanation or guidance to only one user.

[0267] <Example 4>[Occurrence of reverse view in multi-viewpoint video and its prevention technology] In a multi-viewpoint video display device using a lenticular lens, a so-called reverse view caused by the relative positional relationship between the position of the observer's eyes and the lenticular lens and the liquid crystal panel becomes a problem. As already shown in Fig. 16(A), for example, light from the image displayed on pixel 6 reaches the observer's right eye, and light from the image displayed on pixel 4 reaches the observer's left eye, and due to the parallax between the image by these pixels 6 and the image by pixel 4, the observer can recognize a stereoscopic image. On the contrary, reverse view refers to a phenomenon in which, due to the positional relationship between the observer's eyes and the lenticular lens, light from pixels with a parallax that is impossible in daily scenes reaches the observer's right eye and left eye, respectively.

[0268] When reverse vision occurs, the observer cannot correctly recognize an image that can originally be recognized as a three-dimensional image. Also, as explained in FIGS. 18(A) and (B), reverse vision occurs when the observer moves in the left-right direction (X direction) and the pixels reaching the observer's right eye and left eye deviate from the range from pixel 1 to pixel 9. In this case, the observer cannot recognize the object as having a three-dimensional shape, and moreover, a visual discomfort that is not experienced in daily scenes will occur. And in some cases, dizziness or a feeling of intoxication will occur, so some preventive measures are necessary. Hereinafter, the causes of reverse vision, which is the point of the present invention, and countermeasures therefor will be described.

[0269] FIG. 19 is a diagram for explaining the mechanism of reverse vision in a multi-viewpoint video display device using a lenticular lens. The position of the observer (user) in FIG. 19 is in a state where it has moved in the right direction (X direction) as seen from the observer himself / herself compared to the position of the observer in FIG. 16(A). As a result, in FIG. 19, light from the image displayed on pixel 2 reaches the observer's right eye, and light from the image displayed on pixel 9 reaches the observer's left eye.

[0270] When the observer's eyes are at the position shown in FIG. 19, as shown in FIG. 17, video light obtained by photographing a subject (the face of a person facing left) by camera No. 9 reaches the observer's left eye, and video light obtained by photographing a subject (the face of a person facing the right front) by camera No. 2 reaches the observer's right eye. That is, video light of the face of a person facing left as seen from the observer reaches the observer's left eye, and video light of the face of a person facing the right front as seen from the observer reaches the observer's right eye, and the observer simultaneously observes two images having a parallax that is impossible in reality with the right eye and the left eye. This state is a state in which reverse vision occurs in a multi-viewpoint image (video).

[0271] As described above, the occurrence of reverse viewing depending on the position of the observer is an issue that cannot be avoided in principle in a multi-viewpoint image (video) display device using a lenticular lens. Conventionally, for this issue, a technique has been proposed in which the position of the observer's eye is detected using a sensor such as a camera, and as a result, when it is specified that reverse viewing has occurred, the position of the pixels on the liquid crystal panel is changed to prevent reverse viewing.

[0272] However, according to this technique, first, it is necessary to accurately detect the position of the observer's eye, and further, according to the detection result, it is necessary to change the position of the pixels on the liquid crystal panel so that reverse viewing does not occur. This not only makes the system large-scale, but also causes a problem that the discomfort (discontinuity) felt by the observer when the position of the pixels is changed cannot be eliminated.

[0273] In order to solve the above problems, the inventors have examined the mechanism of reverse viewing and the cause of reverse viewing as described below, and compared with the prior art, they have devised a reverse viewing prevention method that prevents reverse viewing with a simpler configuration and further reduces the discomfort felt by the observer when the position of the pixels on the liquid crystal panel is changed in the prior art. Hereinafter, the factors causing reverse viewing, which are the main points of the present invention, and the method for eliminating these factors will be specifically described.

[0274] As already described, in the state where reverse viewing shown in FIG. 19 occurs, light from the image displayed on pixel 2 reaches the observer's right eye, and light from the image displayed on pixel 9 reaches the observer's left eye. Here, pay attention to the light paths through which the light from each pixel reaches the observer's right and left eyes. Here, as shown in FIG. 16(A), when nine pixels from pixel 1 to pixel 9 are grouped as one group, the light from each pixel reaches the observer's eye through the lenticular lens corresponding to the group, that is, the lenticular lens existing directly above (vertically above) pixels 1 to 9. In this case, reverse viewing does not occur.

[0275] In contrast, in the case of FIG. 19, for the light paths of the light reaching the left eye of the observer from pixel 9, that is, the light paths L1, L2, and L3 from pixel 9, the light emitted from pixel 9 reaches the left eye of the observer through the lenticular lens directly above (vertically above) another pixel group adjacent to the pixel 9, rather than through the lenticular lens directly above (vertically above) pixel 9 itself. That is, as shown in FIG. 19, when the light paths L1, L2, and L3 from the pixel (pixel 9 in FIG. 19) existing at the end of the pixel group reach the observer's eye through the lenticular lens directly above (vertically above) the pixel group adjacent to the pixel group of that pixel itself rather than through the lenticular lens of its own pixel group, reverse vision occurs. This is the mechanism of the occurrence of reverse vision.

[0276] In FIG. 19, the light from the image displayed on pixel 2 reaches the right eye of the observer, and for the light paths R1, R2, and R3 from pixel 2, they reach the right eye of the observer through the lenticular lens directly above (vertically above) pixel 2. As a result, the light paths R1, R2, and R3 from pixel 2 to the right eye of the observer do not cause reverse vision.

[0277] Next, when the observer further moves in the left - right direction (X - direction), the state shown in FIG. 20 is reached. In the state shown in FIG. 20, the light from the image displayed on pixel 1 reaches the right eye of the observer, and the light from the image displayed on pixel 8 reaches the left eye of the observer. Also in this case, the observer will again observe a parallax that is impossible in reality. That is, it is in a reverse - vision state. Also in the state of FIG. 20, the light paths R1, R2, and R3 from pixel 1, which exists at the end of one pixel group, to the right eye of the observer all pass through the lenticular lens directly above (vertically above) the adjacent pixel group.

[0278] As described with reference to FIGS. 19 and 20, in order to eliminate the visual discomfort caused by reverse viewing, among the nine pixels that make up one pixel group corresponding to one lenticular lens, the optical path from pixel 1 or pixel 9, which is located at the outermost end and makes up one pixel group, to the observer's eye should not pass through the adjacent lenticular lens. Next, the specific method will be described.

[0279] One possible method to prevent reverse viewing is to set the luminance of the light (video light) from the pixels located at the outermost ends of one pixel group, which are pixel 9 and pixel 1 in this embodiment, to 0. Then, the light from the images displayed on pixel 9 and pixel 1 will not reach the observer's eye, making it possible to prevent reverse viewing. However, in this method, although the visual discomfort based on reverse viewing is eliminated, the images displayed by the two pixels located at the outermost ends of one pixel group, that is, pixel 9 and pixel 1, will substantially disappear. As a result, the number of viewpoints that make up the multi-viewpoint image decreases. In the case of this embodiment, the number of viewpoints, which was originally nine, decreases to seven.

[0280] Next, while solving the above-described problem, that is, the problem that the number of viewpoints that make up the multi-viewpoint image decreases, a configuration that does not cause reverse viewing will be considered. In FIGS. 19 and 20, in any case, among the nine pixels that make up one pixel group corresponding to one lenticular lens, the video light from pixel 1 or pixel 9, which is located at the outermost end, reaches the observer's eye through the adjacent lenticular lens rather than the lenticular lens corresponding to one pixel group. It has been found that "the video light from the pixel located at the outermost end of the pixel group reaches the observer's eye through the adjacent lenticular lens" is the cause of reverse viewing and the mechanism of reverse viewing occurrence.

[0281] According to the mechanism of reverse vision occurrence described above, in FIG. 19, if the video light from pixel 9 and in FIG. 20, the video light from pixel 1 is prevented from reaching the observer's eye through the adjacent lenticular lens, it becomes possible to prevent the occurrence of reverse vision. Therefore, the inventors considered that reverse vision can be prevented not by setting the luminance of the video light emitted from pixel 9 and pixel 1 to 0, but by setting the diffusion angle of the video light emitted from these pixels to a predetermined angle or less. Hereinafter, the specific configuration will be described. In the following description, the diffusion angle of the video light may also be referred to as the divergence angle.

[0282] FIG. 21 is a diagram showing the viewing angle θL of the lenticular lens 1103 and the diffusion angle θV of the video light in Example 4 of the present invention. In FIG. 21, as an example, the viewing angle θL of the lenticular lens is 40 degrees, in other words, θL = ± 20 degrees, while the diffusion angle θV of the video light is 40 degrees. Also, in FIG. 21, as an example, the pitch in the X direction of the lenticular lens (the repetition length of one line when one semi-cylindrical lens is regarded as one line) is shown when it is 60 LPI (Line Per Inch). Since it is 60 LPI, the pitch in the X direction of the lenticular lens can be calculated as 432 μm (1 inch / 60). Furthermore, 9 viewpoints correspond to one pitch of the lenticular lens. Therefore, the X-direction length (width) of one pixel is 48 μm (= 432 / 9).

[0283] Furthermore, in FIG. 21, also as an example, the focal length of the lenticular lens is shown when it is 700 μm (0.7 mm). Therefore, if the distance from the bottom surface (plane) of the lenticular lens to the surface of the liquid crystal screen (the display surface on which the pixels are arranged) is 700 μm, the observer can observe a clear multi-viewpoint image without blurring. In commercially available lenticular lenses, the above-described pitch, viewing angle, and focal length are predetermined as fixed values and can be appropriately selected according to the use of the lenticular lens (2 viewpoints or multi-viewpoints) and the display size.

[0284] As is apparent from FIG. 21, the viewing angle θL of the lenticular lens 1103 and the focal length L1 determine the range within which the user can observe the pixels through the lenticular lens. Further, FIG. 21 shows both the viewing angle θL of the lenticular lens 1103 and the divergence angle θV of the light (video light) emitted from one pixel.

[0285] Now, assume that the viewing angle θL of the lenticular lens 1103 is equal to the divergence angle θV of the light (video light) emitted from one pixel, or that the viewing angle θL is larger than the divergence angle θV, that is, θL≧θV Let's assume this relationship holds. In FIG. 21, specifically, θL = θV = 40 degrees is shown.

[0286] Next, as described above, the trajectory of the video light from the pixel reaching the user's eye when the restriction of "θL = θV = 40 degrees" is imposed will be explained.

[0287] FIG. 22 is a diagram showing a state where the user's left eye is located at the leftmost side of the viewing angle θL of the lenticular lens 1103 as seen from the observer. At this time, referring to FIG. 19, the video light from pixel 9 reaches the user's left eye, and the video light from pixel 2 reaches the user's right eye. However, in the case of FIG. 22, since the divergence angle of the video light from pixel 9 is restricted to θV = 40 degrees, the video light (trajectory E9) from pixel 9 does not reach the user's left eye, and as a result, reverse vision does not occur.

[0288] On the other hand, as opposed to the case of FIG. 22, FIG. 23 shows a state where the user's right eye is positioned at the rightmost side of the viewing angle θL of the lenticular lens 1103 when viewed from the observer. At this time, referring to FIG. 21, the image light from pixel 1 reaches the user's right eye, and the image light from pixel 8 reaches the user's left eye. However, in the case of FIG. 23, since the divergence angle of the image light from pixel 1 may be limited to θV = 40 degrees, the image light (trajectory E1) from pixel 1 does not reach the user's right eye, and as a result, reverse viewing does not occur.

[0289] As described above, when the limitation of "θL = θV = 40 degrees" is applied, as shown in FIGS. 22 and 23, the user cannot observe the image light from pixel 1 and pixel 9, respectively. More generally, between the viewing angle θL of the lenticular lens 1103 and the divergence angle θV of the light (image light) emitted from one pixel, θL ≧ θV when the relationship holds, a reverse viewing state as described in FIGS. 19 and 20 does not occur.

[0290] Also, in the embodiment described with reference to FIGS. 21 to 23, for the viewing angle θL of the lenticular lens 1103, θL = 40 degrees, and for the divergence angle θV of the image light, the case of θV = 40 degrees was described as an example. However, as a practical viewing angle θL of the lenticular lens for displaying a multi-viewpoint image, θL = 20 degrees to 40 degrees, and generally, a lenticular lens with a relatively narrow viewing angle is used.

[0291] Also in the above embodiment, if θL = 20 degrees to 40 degrees, for example, it is possible to display a 9-viewpoint multi-viewpoint image. Therefore, in order to prevent the occurrence of reverse viewing, the divergence angle θV of the image light should be adjusted according to the viewing angle θL of the lenticular lens, θL ≧ θV and the divergence angle θV of the image light may be set so that the relationship holds. More specifically, by setting the value of θV to θV = 20 degrees to 40 degrees, it is possible to preferably prevent the occurrence of reverse viewing.

[0292] Next, a specific configuration for satisfying “θL ≧ θV” will be described. The light (video light) emitted from the liquid crystal display panel 11 used in this embodiment has very narrow-angle characteristics (narrow diffusion characteristics) in terms of its diffusion characteristics compared to liquid crystal display panels used for general TV applications, as shown in FIG. 12. For example, as shown in Example 1 of FIG. 12, the viewing angle at which the luminance becomes 50% of the front view (angle 0 degrees) is 13 degrees, and the viewing angle at which the luminance becomes 0% of the front view is less than 30 degrees. Further, in the case of the viewing angle characteristics shown in Example 2 of FIG. 12, the viewing angle at which the luminance becomes 50% of the front view (angle 0 degrees) is as narrow as about 5 degrees, and the viewing angle at which the luminance becomes 0% of the front view is less than 15 degrees.

[0293] Therefore, if the video display device 1 is configured by combining the liquid crystal display panel 11 and the light source device 13 having narrow diffusion characteristics as shown in FIGS. 5 to 10, the relationship between the viewing angle θL of the lenticular lens 1103 and the diffusion angle θV of the light (video light) emitted from one pixel can be set to “θL ≧ θV”. For example, when the viewing angle θL of the lenticular lens 1103 is about 40 degrees, it is possible to set the diffusion angle θV of the video light to 40 degrees or less, that is, a narrow angle of ±20 degrees or less, by using the light source device 13 having viewing angle characteristics (narrow diffusion characteristics) as shown in Example 2 of FIG. 12.

[0294] Also, by disposing the video light control sheet 334 on the video light emission side of the video display device 1 formed by combining the liquid crystal display panel 11 and the light source device 13 having narrow diffusion characteristics as described above, it is possible to further realize a video display device that emits video light having narrow-angle diffusion characteristics. Further, by disposing the video light control sheet 334 on the video light emission side of the video display device 1 formed by combining the liquid crystal display panel 11 and the light source device 13 having normal diffusion characteristics, it is also possible to realize a video display device that emits video light having narrow-angle diffusion characteristics.

[0295] FIG. 24 shows a specific method and a configuration example of applying the above-described video light control sheet 334 to an airborne video display device. First, as shown in FIG. 24(A), the video light control sheet 334 is provided on the emission surface of the liquid crystal display panel 11. In FIG. 24(A), the emission surface of the liquid crystal display panel 11 is shown as a plane (X-Y plane) formed by the illustrated X-axis and Y-axis. The video light control sheet 334 has a light transmission part and a light absorption part on the emission surface (X-Y plane) side of the liquid crystal display panel 11, as will be described later.

[0296] FIG. 24(B) shows a vertical sectional view (X-Z plane) of a video display device 1 having a configuration in which the video light control sheet 334 is disposed on the video light emission surface 335 of the liquid crystal display panel 11. The video light control sheet 334 is configured such that the light transmission part 336 and the light absorption part 337 are alternately arranged on the emission surface (X-Y plane) side of the liquid crystal display panel 11, and is adhesively fixed to the video light emission surface 335 of the liquid crystal display panel 11 by an adhesive layer 338.

[0297] As specific dimensions of the video light control sheet 334, for example, the pitch B of the video light control sheet 334 in which the distance d2 of the transmission part 336 is 300 μm and the distance (thickness) d1 of the light absorption part 337 is 40 μm is set to 340 μm. A shown in the figure indicates the size (length in the X direction = width) of one pixel, which is, for example, about 50 μm. Further, by setting the thickness of the video control sheet 334 to be 2 / 3 or more of the pitch B, the effect of using the diffusion characteristic of the video light as a clamping angle is improved. With the video light control sheet 334 having the above-described configuration, sufficient transmission characteristics can be ensured for the video light, and the diffusion characteristic of the video light from the video display device 1 can be sufficiently used as a clamping angle.

[0298] Also, in the configuration shown in FIGS. 24(A) and (B), moire may occur due to interference caused by the pitch between the pixels of the liquid crystal display panel 11 and the transmissive portions and light absorption portions of the video light control sheet 334. To reduce such moire, the vertical stripes (diagonal lines in the figure) formed by the transmissive portions and light absorption portions of the video light control sheet 334 are arranged at a predetermined angle (tilt) θ0 with respect to the pixel arrangement (X-axis and Y-axis) of the liquid crystal display panel 11. At this time, as the angle (tilt) θ0, by setting it to 5 degrees to 15 degrees, moire can be preferably reduced.

[0299] Note that, as the above-described video light control sheet 334, for example, a view angle control film (VCF: View Control Film) of Shin-Etsu Polymer Co., Ltd. is suitable. The structure of the VCF is such that transparent silicon and black silicon are alternately arranged, and a synthetic resin is arranged on the light incident / output surface, resulting in a sandwich structure. With the above view angle control film, the diffusion angle of the video light can be set to an included angle of 20 degrees to 30 degrees, and it can be applied as the video light control sheet 334 of this embodiment.

[0300] As described above, in this embodiment, the occurrence of reverse viewing and its prevention technology in a multi-viewpoint video have been described. In this embodiment, as the video display device 1, a liquid crystal display device using a liquid crystal panel has been described as an example. However, the present invention is not limited to this, and even when an organic EL display device or a display device using micro LEDs is used, by using the above-described video light control sheet 334, a video display device that emits video light having narrow-angle diffusion characteristics can be realized. As a result, in a multi-viewpoint video display device equipped with a lenticular lens, even when an organic EL display device or a display device using micro LEDs is used as the video display device, the occurrence of reverse viewing can be prevented.

[0301] Next, FIGS. 25 and 26 schematically show a state in which multi-viewpoint floating images 3 are generated by passing image light emitted from a multi-viewpoint video display device composed of a video display device 1 and a lenticular lens 1103 through a retroreflective plate 2, a polarization separation member 101, etc., as shown in FIGS. 18(A) and (B). The embodiments shown in FIGS. 25 and 26 are both diagrams schematically showing a state in which multi-viewpoint floating images 3 are generated by the above multi-viewpoint video display device, the retroreflective plate 2, the polarization separation member 101, etc. Hereinafter, an optical system that generates multi-viewpoint floating images 3 by the multi-viewpoint video display device (composed of the video display device 1 and the lenticular lens 1103), the retroreflective plate 2, the polarization separation member 101, etc. is referred to as a multi-viewpoint airborne floating video system.

[0302] The difference between the two embodiments of FIGS. 25 and 26 lies in the fact that the left-right order of the multi-viewpoint floating images 3 generated by the multi-viewpoint video display device is different. That is, in FIG. 25, it is based on the multi-viewpoint video display device corresponding to FIG. 18(A). When viewed from the user, images by cameras No. 1 to No. 9 are assigned to the pixels 1 to 9 of the liquid crystal panel from left to right of the multi-viewpoint video display device. As a result, in the multi-viewpoint floating images 3 generated through the multi-viewpoint airborne floating video system, the order of the multi-viewpoint images is, conversely, images by cameras No. 1 to No. 9 are displayed from right to left when viewed from the user.

[0303] On the other hand, in FIG. 26, it is based on the multi-viewpoint video display device corresponding to FIG. 18(B). Images by cameras No. 1 to No. 9 are assigned to the pixels 1 to 9 of the liquid crystal panel from right to left of the multi-viewpoint video display device. As a result, in the multi-viewpoint floating images 3 generated through the multi-viewpoint airborne floating video system, when viewed from the user, the order of the multi-viewpoint images is, conversely, images by cameras No. 1 to No. 9 are displayed from left to right, contrary to FIG. 26.

[0304] As described above, in the multi-viewpoint spatial floating image 3 generated via the multi-viewpoint airborne floating video system, since the multi-viewpoint airborne floating video system is interposed, the order of the multi-viewpoint videos displayed on the video display device 1 and the order of the multi-viewpoint videos in the multi-viewpoint spatial floating image 3 are recognized by the user in the reverse order. That is, when providing the multi-viewpoint spatial floating image 3 having motion parallax to the user, depending on the purpose of what order of multi-viewpoint images is suitable to provide to the user, the order of the images by Camera No. 1 to No. 9 can be appropriately determined and arranged for the pixels on the liquid crystal panel 11.

[0305] Explaining this more specifically, in the embodiment of FIG. 25, when the multi-viewpoint spatial floating image 3 with the face of a person (e.g., a concierge) who gives some guidance or explanation to the user as the subject is viewed from the user, the order of the multi-viewpoint spatial floating image 3 is such that the images by Camera No. 1 to No. 9 are recognized from right to left. In this case, the concierge always directs their line of sight towards the user regardless of the user's position. On the other hand, in the embodiment of FIG. 26, when the multi-viewpoint spatial floating image 3 with the face of the concierge as the subject is viewed from the user, the order of the multi-viewpoint spatial floating image 3 is such that the images by Camera No. 1 to No. 9 are recognized from left to right. In this case, the concierge always directs their line of sight in a certain direction, that is, the front direction, regardless of the user's position.

[0306] As described above, in the embodiment of FIG. 25, when the user views the concierge as the multi-viewpoint spatial floating image 3, it is particularly suitable in a scene where the concierge always conveys information such as some guidance or explanation to the user together with voice, and the user can easily empathize with the concierge and can concentrate on the guidance and explanation by the concierge, bringing about such an effect.

[0307] On the one hand, as shown in FIG. 26, when a user views the concierge as the multi-viewpoint spatial floating image 3, the concierge always appears to be speaking while facing a certain direction, that is, the front. In this case, the user recognizes that the concierge is not speaking only to him / herself, and has the effect of feeling that, for example, some kind of presentation is being made to an unspecified number of people around the multi-viewpoint spatial floating image 3.

[0308] That is, when displaying the concierge as the multi-viewpoint spatial floating image 3, among the two embodiments described above, whether to adopt a display form in which the concierge always talks to the user as shown in FIG. 25 (referred to as "display form A"), or a display form in which the concierge always speaks while facing the front as shown in FIG. 26 (referred to as "display form B"), it is possible to appropriately select the above two display forms.

[0309] Also, in both cases of FIGS. 25 and 26 above, by setting the relationship between the viewing angle θL of the lenticular lens 1103 used and the diffusion angle θV of the light (video light) emitted from one pixel as "θL≧θV", the user will not experience reverse viewing regardless of the direction from which the concierge as the multi-viewpoint spatial floating image 3 is viewed, which is preferable.

[0310] <Embodiment related to a kiosk terminal> As described above, two forms of displaying the concierge as the multi-viewpoint spatial floating image 3, that is, "display form A" and "display form B", have been described with reference to FIGS. 25 and 26. Next, an embodiment in which the multi-viewpoint airborne floating video display device 1000 to which the present invention is applied is applied to a so-called kiosk terminal will be described below.

[0311] A kiosk terminal has conventionally been an information terminal for an unspecified number of people to access necessary information and utilize various services through a man-machine interface or user interface such as touch panel operations. Kiosk terminals are installed in public facilities, transportation facilities, entertainment facilities such as amusement parks, and in recent years, also inside so-called convenience stores. Kiosk terminals are used, for example, for selling various tickets and for administrative services (such as issuing resident cards). Kiosk terminals may also be used for route guidance and the like.

[0312] In the following description of the embodiments, an information terminal having a specific configuration is expressed using the term "kiosk terminal". Instead of this term "kiosk terminal", it may also be expressed as "information terminal", "information display device", "information processing terminal", "ticket issuing terminal", "document issuing terminal", "administrative terminal", "service terminal", etc. The term "kiosk terminal" mainly used in the description of the embodiments is used as a representative example of these terms.

[0313] Figure 27 shows an example of the appearance of a kiosk terminal to which the present invention is applied. This kiosk terminal 1400 includes, for example, a metal housing 1450 that is about 120 to 50 cm in height. An opening 1410 is provided on the surface of the housing 1450 (the side facing the user, particularly the inclined surface 1470). Through this opening 1410, a concierge as a multi-viewpoint spatial floating image 3 is displayed. The concierge as the multi-viewpoint spatial floating image 3 provides explanations and guidance for various services, for example, through interaction with the user. Also, the concierge may guide the user through operations. Further, a take-out port 1430 is provided on a part of the surface of the housing 1450. The take-out port 1430 is a take-out port for the user to take out, for example, tickets or administrative documents as the result of the service obtained by the user through interaction with the concierge. Note that, as an example of a service result output unit configured to output the result of a service, the document take-out port 1430 has been described. However, as the service result output unit, for example, an audio output device that outputs the result of a service (e.g., route guidance) by voice, a display that allows the user to visually recognize the result of a service (e.g., bank procedures), etc. may be used.

[0314] In this embodiment, since the concierge as the multi-viewpoint spatial floating image 3 is displayed as a multi-viewpoint video with motion parallax, compared to the case where a two-dimensional planar image is simply displayed as an aerial floating image, the user can obtain a feeling as if an actual person (concierge) exists on the kiosk terminal 1400. Further, the concierge carefully explains to the user about the operation method of the kiosk terminal 1400 and the like. Therefore, even a user who touches the kiosk terminal for the first time can more easily operate the kiosk terminal 1400 without confusion and receive the desired service.

[0315] FIG. 28 is a schematic diagram showing the internal structure of the kiosk terminal 1400 in FIG. 27. In FIG. 28, an internal perspective Y-Z cross section is shown when the housing 1450 in FIG. 27 is viewed from the left side. The upper part of the housing 1450 has an inclined surface 1470. Inside the housing 1450, a video display device 1 that constitutes the airborne floating video display device 1000 shown in FIG. 15, a lenticular lens 1103, a retroreflective plate 2, a polarization separation member 100, etc. are accommodated. With the configuration of FIG. 28, the point that the user can visually recognize the airborne floating video 3 as a multi-viewpoint video with motion parallax is the same as described with reference to FIG. 15.

[0316] Inside the lower part of the housing 1450, although not shown, other components such as a control device on which the control unit 1110 shown in FIG. 3 is implemented, a communication device on which the communication unit 1132 is implemented, an audio output unit 1140, an audio input / output device on which the audio signal input unit 1133 is implemented, and further a power supply device may be accommodated. Also, on the outer lower part of the housing 1450, as shown in FIGS. 27 and 28, a human presence sensor 1460 may be provided. The human presence sensor 1460 detects that a person has approached the kiosk terminal 1400, and sends the detection result to the control unit 1110, and the control unit 1110 controls the audio output unit 1140 to make the concierge utter words such as "Hello" and "Welcome".

[0317] Also, in FIG. 28, a sensor (corresponding to the airborne operation detection sensor 1351 in FIG. 15) that detects an operation such as the user touching a specific part of the airborne floating video 3 with a fingertip may be provided, and according to the operation by the above user, the airborne floating video 3 may be changed from the concierge screen to, for example, a menu screen or the like. The control device may execute a predetermined process (for example, a process of providing services such as document issuance and route guidance) based on the detected operation.

[0318] The inclined surface 1470 of the housing 1450 has a predetermined angle with respect to the horizontal plane (Y direction) and is provided with an opening 1410 on the inclined surface 1470. A transparent member 100 such as glass is fitted into this opening 1410, and a virtual floating image 3 that is a real image is formed at a predetermined position outside the inclined surface 1470. To the user, the concierge as the multi-viewpoint spatial floating image 3 appears to protrude forward and float with respect to the inclined surface 1470. Therefore, the user can suitably visually recognize the concierge as the multi-viewpoint spatial floating image 3 displayed on the virtual floating image display unit from an obliquely upward viewpoint E to an obliquely downward line of sight, similar to FIG. 15.

[0319] As described above, according to this embodiment, it is possible to display the concierge as a multi-viewpoint spatial floating image with motion parallax through the opening 1410 of the kiosk terminal 1400. Therefore, compared with the case of simply displaying it as a planar image, it is possible to provide a more suitable concierge image to the user. As a result, even for a user who is not used to operating the virtual floating image or an elderly user, etc., it is possible to provide operation guidance by the concierge as a human image that is close to an actual human image and easy to feel familiar with. Further, according to the present invention, the occurrence of reverse viewing, which is a problem in multi-viewpoint images, can also be prevented, so that the sense of discomfort associated with changes in the position of the user, etc., is eliminated.

[0320] <Usage scene of the kiosk terminal> The embodiments of the present invention related to the kiosk terminal have been described above. Next, a usage scene of the kiosk terminal by an actual user will be described. FIG. 29 is a diagram showing a scene where a single user uses a kiosk terminal as a virtual floating image display system. In FIG. 29, a concierge (female face) as the multi-viewpoint spatial floating image 3 is displayed on the kiosk terminal 1400.

[0321] Here, as for the concierge as the multi-viewpoint spatial floating image 3, as long as the user located near the kiosk terminal 1400 can view the concierge within the visible range, no matter where the user is located, the concierge can always be visually recognized as if it is always looking in the direction of the user himself / herself. More specifically, as shown in FIG. 29, when the user stands diagonally to the left of the kiosk terminal, the concierge can be visually recognized by the user as facing the direction where the user stands, that is, diagonally to the left. On the other hand, when the user stands diagonally to the right of the kiosk terminal, the concierge can be visually recognized by the user as facing the direction where the user stands, that is, diagonally to the right.

[0322] As described above, in order to display the concierge as the multi-viewpoint spatial floating image 3, the concierge as the multi-viewpoint image may be displayed in the "display format A" shown in FIG. 25. As a result, the kiosk terminal 1400 can display the video of the concierge by camera No. 1 to No. 9 as a multi-viewpoint (9 viewpoints) spatial floating image with motion parallax in order from the right as the user faces the multi-viewpoint spatial floating image displayed on the kiosk terminal 1400.

[0323] Also, when the user moves relative to the kiosk terminal 1400, for example, from the right side towards the left side, the user can recognize the motion parallax peculiar to the multi-viewpoint image as shown in FIG. 25, and moreover, the state of reverse viewing does not occur, and the concierge as the spatial floating image can be visually recognized as a stereoscopic image.

[0324] As a result, in the kiosk terminal according to this embodiment, compared with the case where the spatial floating image is simply displayed as a two-dimensional image, the user can visually recognize the concierge as a multi-viewpoint video with stereoscopic and motion parallax as if it were an actual person. Furthermore, even when the user moves left and right near the kiosk terminal 1400, the state of reverse viewing does not occur, and the user can always obtain a feeling as if the concierge is always looking in the direction of the user himself / herself and talking to him / her, thus obtaining a new and unprecedented effect.

[0325] As described above, according to the present invention, by using the image display device 1 including the liquid crystal display panel 11 as an image display element and the light source device 13 having the diffusion characteristics with a sandwiching angle, it is possible to effectively prevent the reverse view generated in the multi-viewpoint image display device. More specifically, the viewing angle of the lenticular lens for displaying a multi-viewpoint video is generally 40 degrees to 60 degrees (±20 to 30 degrees from the center), while by using the light source device 13 having the diffusion characteristics with a sandwiching angle of 30 degrees (±15 degrees from the center) as the light source of the image display device 1, the occurrence of the reverse view can be effectively prevented.

[0326] Also, even in an image display device in which the liquid crystal display panel 11 is combined with a normal light source device that does not have the diffusion characteristics with a sandwiching angle, by disposing the video light control sheet 334 on the video light emission side of the liquid crystal display panel 11, the relationship between the diffusion angle θV of the video light from the image display device and the viewing angle θL of the lenticular lens is set to θL≧θV, and the occurrence of the reverse view can be effectively prevented. The image display device may include a video light control sheet between the lenticular lens on the video light emission side, and the relationship between the viewing angle θL of the lenticular lens and the diffusion angle θV of the video light emitted from the image display device through the video light control sheet may be set to θL≧θV.

Explanation of Reference Numerals

[0327] 1... Image display device, 2... Retroreflective plate (retroreflective sheet), 3... Virtual image (floating virtual image), 105... Windshield, 100... Transparent member, 101... Polarization beam splitter, 101B... Polarization beam splitter, 12... Absorptive polarizing plate, 13... Light source device, 54... Light direction conversion panel, 151... Retroreflective plate, 102, 202... LED substrate, 203... Light guide, 205, 271... Reflective sheet, 206, 270... Phase difference plate, 230... User, 334... Video light control sheet, 1000... Floating virtual image display device, 1103... Lenticular lens, 1110... Control unit, 1160... Video control unit, 1180... Imaging unit, 1102... Video display unit, 1350... Air operation detection unit, 1351... Air operation detection sensor, 1400... Kiosk terminal

Claims

1. An airborne floating image display device that forms an airborne floating image in the air, a display unit that displays an image of an object, a lenticular lens disposed on the image light emission side of the display unit, an optical system that generates an airborne floating image based on the image displayed by the display unit, comprising: the display unit displays, as the object, a multi-viewpoint image obtained by photographing or rendering from a plurality of viewpoints, the relationship between the viewing angle θL of the lenticular lens and the divergence angle θV of the image light emitted from the display unit is θL ≧ θV is, an airborne floating image display device.

2. In the airborne floating image display device according to Claim 1, further comprising an image light control sheet disposed on the image light emission side of the display unit and between the lenticular lens and the display unit, the relationship between the viewing angle θL of the lenticular lens and the divergence angle θV of the image light emitted from the display unit through the image light control sheet is θL ≧ θV is, an airborne floating image display device.

3. In the airborne floating image display device according to Claim 1, the lenticular lens is disposed between the display unit and the optical system, an airborne floating image display device.

4. In the airborne floating image display device according to Claim 1, the lenticular lens is disposed at a predetermined distance from the emission surface of the display unit, an airborne floating image display device.

5. In the airborne floating image display device according to Claim 1, the distance between the lenticular lens and the display unit is adjusted by the focal length of the lenticular lens, an airborne floating image display device.

6. In the airborne floating image display device according to Claim 1, the emission surface of the display unit and the incident surface of the lenticular lens are parallel, an airborne floating image display device.

7. In the airborne floating image display device according to Claim 1, the viewing angle θL of the lenticular lens is a value between 20 degrees and 40 degrees, the divergence angle θV of the image light emitted from the display unit is a value between 20 degrees and 40 degrees, an airborne floating image display device.

8. In the airborne floating image display device according to Claim 2, the viewing angle θL of the lenticular lens is a value between 20 degrees and 40 degrees, the divergence angle θV of the image light emitted from the display unit through the image light control sheet is a value between 20 degrees and 40 degrees, an airborne floating image display device.

9. In the airborne floating image display device according to Claim 1, The object has a shape as a portrait, A floating image display device.

10. In the floating image display device according to claim 1, The lenticular lens is disposed between the display unit and the optical system, A housing that houses the display unit and the optical system, A control device that executes a predetermined process based on a predetermined operation, and is provided with, The object has a shape as a portrait, The portrait displayed as the multi-viewpoint image has a motion parallax as the user moves, A floating image display device.

11. In the floating image display device according to claim 9, The orientation of the face of the portrait displayed as the multi-viewpoint image changes so as to face the user according to the movement of the user, A floating image display device.

12. In the floating image display device according to claim 9, The portrait is a concierge, A floating image display device

13. In the floating image display device according to claim 1, A sensor for detecting an operation by a user on the floating image, A housing including the display unit and the optical system, A control device that executes a predetermined process based on the detected operation, and is provided with, The control device executes a process of providing a service based on the detected operation, The floating image display device further includes a service result output unit that outputs a result of the service. A floating image display device.

14. In the floating image display device according to claim 13, The control device executes a process of issuing a document in the process, A part of the housing is provided with a document outlet as the service result output unit, The floating image display device is a kiosk terminal having a function of issuing a ticket or an administrative certificate as the document. A floating image display device.

15. In the floating image display device according to claim 2, The lenticular lens is disposed between the display unit and the optical system, A floating image display device.

16. In the floating image display device according to claim 2, The lenticular lens is disposed at a predetermined distance from the emission surface of the display unit, A floating image display device.

17. In the floating image display device according to claim 16, The distance between the lenticular lens and the display unit is adjusted by the focal length of the lenticular lens, A floating image display device.

18. In the airborne floating image display device according to claim 2, the emission surface of the display unit and the incident surface of the lenticular lens are parallel, Airborne floating image display device.

19. In the airborne floating image display device according to claim 2, the object has a shape as a portrait, Airborne floating image display device.

20. In the airborne floating image display device according to claim 2, the lenticular lens is disposed between the display unit and the optical system, a housing that houses the display unit and the optical system, a control device that executes a predetermined process based on a predetermined operation, and includes: the object has a shape as a portrait, the portrait displayed as the multi-viewpoint image has a motion parallax as the user moves, Airborne floating image display device.

21. In the airborne floating image display device according to claim 19, the orientation of the face of the portrait displayed as the multi-viewpoint image changes so as to face the user according to the movement of the user, Airborne floating image display device.

22. In the airborne floating image display device according to claim 21, the portrait is a concierge, Airborne floating image display device

23. In the airborne floating image display device according to claim 2, a sensor for detecting an operation by the user on the airborne floating image, a housing including the display unit and the optical system, a control device that executes a predetermined process based on the detected operation, and includes: the control device executes a process of providing a service based on the detected operation, and further includes a service result output unit that outputs a result of the service, Airborne floating image display device.

24. In the airborne floating image display device according to claim 23, the control device executes a process of issuing a document in the process, a part of the housing includes a document outlet as the service result output unit, and it is a kiosk terminal having a function of issuing a ticket or an administrative certificate as the document, Airborne floating image display device.

Images