Spatial floating image display device

Abstract

To suitably display a video to the outside of a space, and to contribute to the Sustainable Development Goals of "3 Good health and well-being", "9 Industry, innovation and infrastructure" and "11 Sustainable cities and communities".SOLUTION: A spatial-suspended video information display system includes: a first display panel for displaying a video; a light source device for the first display panel; a retroreflective member for reflecting video light from the first display panel and displays a spatial-suspended video of a real image in the air with the reflected light; and a second display panel for displaying a video on a surface.SELECTED DRAWING: Figure 14

Description

Technical Field

[0001] The present invention relates to a spatial floating video information display system and an optical system used therefor.

Background Art

[0002] As a spatial floating information display system, a video display device that directly displays a video toward the outside and a display method that is displayed as a spatial screen are already known. Also, a detection system for reducing false detection of operations on the operation surface of the displayed spatial image is disclosed, for example, 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] As a spatial floating information display system, a video display device that directly displays a video toward the outside and a display method that is displayed as a spatial screen are already known. However, in the above-described conventional spatial floating video information display system, there are no means for preventing problems that occur when external light enters the retroreflective member that generates the spatial floating video, and as a detection system for operating the video displayed on a video display system having a composite configuration in which a spatial floating video display device and a flat panel display are provided side by side on the same operation surface in space, there is no consideration for optimization technology of the design including the light source of the video display device that is the video source of the spatial floating video.

[0005] An object of the present invention is to provide a method for accurately operating a spatial image and a display image of a flat panel display in a system in which a spatial floating image display with high visibility (apparent resolution and contrast) and reduced influence of external light is possible and is installed side by side with a flat panel display in a spatial floating information display system or a spatial floating video display device, and a technology capable of displaying a suitable video.

Means for Solving the Problems

[0006] In order to solve the above problems, for example, the configuration described in the claims is adopted. This application includes a plurality of means for solving the above problems, and as an example thereof, a spatial floating video display device is listed below. As an example of this application Spatial floating image display device includes a first display panel for displaying a video, a light source device for the first display panel, a retroreflective member that reflects the video light from the first display panel and displays a real image of a spatial floating video in the air by the reflected light, and a second display panel for displaying a video on the surface. The device includes a first sensor for sensing a spatial region corresponding to the spatial floating image, and a second sensor for performing sensing corresponding to the image displayed on the second display panel, and the sensing region of the first sensor and the sensing region of the second sensor exist on the same plane.

Effects of the Invention

[0007] According to the present invention, even when external light is incident, there is no deterioration in the image quality of the spatial floating video, and the spatial floating video information can be preferably displayed. In addition, by providing a spatial floating video display device and a display, an operation input can be performed without directly touching the display screen. Problems, configurations, and effects other than the above will be clarified by the description of the following embodiments.

Brief Description of the Drawings

[0008]

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Embodiments 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 content of the embodiments (hereinafter also referred to as "the present disclosure") described below. The present invention also extends to the scope of the technical idea described in the spirit of the invention or the scope of the claims or equivalents thereof. Also, the configurations of the embodiments (examples) described below are merely illustrative, 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.

[0010] Also, in the drawings for explaining the present invention, those having the same or similar functions are given the same reference numerals, and while different names may be used as appropriate, repeated explanations of functions and the like may be omitted. In the following description of the 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", "spatial image", "aerial floating video", "spatial 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] The present disclosure relates to an information display system capable of, for example, transmitting an image formed by image light from a large-area image light source through a transparent member that partitions a space such as the glass of a show window and displaying it as a floating image in the interior or exterior of a store (space). The present disclosure also relates to a large-scale digital signage system configured by using a plurality of such information display systems.

[0012] According to the following embodiments, for example, high-resolution video information can be displayed in a floating state on the glass surface of a show window or on a light-transmissive plate material. At this time, by reducing the divergence angle of the emitted image light, that is, making it an acute angle, and further aligning it with a specific polarization, only the regular reflected light can be efficiently reflected to the retroreflective member. For this reason, the utilization efficiency of light is high, and it is possible to suppress ghost images that occur in addition to the main floating image in space, which has been a problem in the conventional retroreflective method, and a clear floating image in space can be obtained.

[0013] In addition, an apparatus including the light source of the present disclosure can provide a novel and highly usable floating image information display system capable of significantly reducing power consumption. Further, according to the technology of the present disclosure, for example, it is possible to provide a floating image information display system for a vehicle capable of displaying a so-called unidirectional floating image that is visible outside the vehicle through a shield glass including a front glass, a rear glass, or a side glass of the vehicle.

[0014] On the one hand, in the conventional spatial floating video information display system, an organic EL panel or a liquid crystal display panel (liquid crystal panel or display panel) is combined with a retroreflective member as a high-resolution color display video source. In the first retroreflective member 2 used in the spatial floating video display device according to the prior art, since the video light diffuses at a wide angle, in addition to the reflected light that is regularly reflected by the retroreflective member which is the first embodiment composed of a polyhedron shown in FIG. 3, as shown in FIG. 3, since the shape used for the retroreflective member 2a is a hexahedron, six ghost images including the ghost images indicated by reference numerals 3a and 3f are generated by the video light incident obliquely, deteriorating the image quality of the spatial floating video. In addition, the same spatial floating video which is a ghost image is viewed not only by the viewer but also by others, and there is a major problem from the security perspective.

[0015] Also, as shown in FIG. 1(A), the second retroreflective member 5 used in the spatial floating video display device is formed by arranging a number of optical members 20 with a certain pitch having a large number of strip-shaped planar light reflection portions perpendicular to one surface of the transparent flat plates 18 and 17 having a constant thickness for the first light control panel 221 and the second light control panel 222, respectively. Here, the light reflection portions of the optical members 20 constituting the first light control panel 221 and the second light control panel 222 are arranged to intersect (in a perpendicular state in this embodiment) in a plan view.

[0016] Subsequently, the operation of the second retroreflective member used in the spatial floating video display device and an embodiment of a specific spatial floating video display device will be described. As shown in FIG. 1(B), the second retroreflective member 5 is generally inclined with an angle of 40 to 50 degrees with respect to the video display device 1. At this time, the spatial floating video 3 exits from the second retroreflective member 5 at the same angle as the angle at which the video light enters the second retroreflective member 5. At this time, the spatial floating video is formed at a symmetric position separated by the same distance as the distance L1 between the video display device 1 and the second retroreflective member 5.

[0017] The imaging mechanism of the floating image in space will be described in detail below with reference to FIGS. 1 and 2. The image light emitted from the image display device 1 provided on one side of the second retroreflective member 5 is reflected by the planar light reflection portion C (the reflection surface of the light reflection member 20) of the second light control member 222, and then reflected by the planar light reflection portion C' (the reflection surface of the light reflection member 20) of the first light control member 221, thereby forming a floating image 3 (real image) at an outer position (the space on the other side) of the second retroreflective member 5. That is, by using this second retroreflective member 5, a floating image information device in space is established, and the image of the image display device 1 can be displayed as a floating image in space.

[0018] In the second retroreflective member 5 described above, since there are two reflection surfaces as described above, as shown in FIGS. 2(A) and 2(B), in addition to the floating image 3, two ghost images 3a and 3b corresponding to the number of reflection surfaces are generated.

[0019] Furthermore, when the intensity of external light is high, when it enters from the upper surface of the second retroreflective member 5, the interval between the reflection surfaces (300 μm or less) becomes short, resulting in light interference and the observation of rainbow-colored reflected light. It was found that there is a drawback that the presence of the retroreflective member is recognized by the observer. Therefore, with the incident angle of external light as a parameter, the area where interference light is generated was experimentally obtained in the measurement environment shown in FIG. 4 so that the interference light generated by the pitch of the reflection surfaces of the retroreflective member 5 due to external light incidence does not return to the observer. The obtained results are shown in FIG. 5. When the pitch of the reflection surfaces is 300 μm and the height of the reflection surfaces is 300 μm, it was found that when the inclination angle θYZ of the retroreflective member is inclined by 35 degrees or more, the interference light does not return to the observer side.

[0020] On the other hand, it was found that in the ratio (H / P) of the pitch P of the above-described light reflection member 20 and the height H of the reflection surface, about 60% of the reflection surface forms a spatially floating image by retroreflection, and the remaining 40% becomes abnormal reflected light that generates a ghost image. In order to improve the resolution of the spatially floating video in the future, it is essential to shorten the pitch of the reflection surface. In addition, in order to suppress the generation of ghost images, it is necessary to make the height of the reflection surface higher than the current level. However, due to manufacturing constraints of the second retroreflective member 5, it is advisable to select a range of 0.8 to 1.2 for the ratio (H / P) of the pitch P to the height H of the reflection surface with respect to the current 1.0.

[0021] As a result of the above-described investigations, the inventors have studied a retroreflective optical system that realizes high image quality of a spatially floating video obtained in a spatially floating video information display system using a second retroreflective member with a small amount of ghost image generation in principle, and have reached the present invention. This will be described in detail below with reference to the drawings.

[0022] <Configuration example of the first retroreflective optical system forming the spatially floating video information display system> FIG. 6 is a diagram showing an example of the form of a retro-optical system used to realize the spatially floating video information display system of the present disclosure. Further, FIG. 6 is a diagram for explaining the overall configuration of the spatially floating video information display system in the present embodiment. Referring to FIG. 6, for example, according to the spatially floating information display system of the present disclosure (hereinafter, also referred to as "the present system"), when the spatially floating video information display system is placed on the desk with respect to the viewer of the spatially floating video, the spatially floating video will be viewed at an angle θ6. At this time, it has been found that the imaging position (angle) of the spatially floating image is optimally arranged such that the sum (θ2 + θ1) of the angle θ2 formed by the display surface of the video display device 1 and the retroreflective member 5 and the angle θ1 formed by the retroreflective member 5 and the spatially floating image is substantially equal for monitoring the spatially floating video.

[0023] As described above, since the floating image is formed at a position symmetrical to the image display device 1 with respect to the second retroreflective member 5, the angles θ1 and θ2 formed by their respective arrangements are equal. Therefore, if the angle θ6 at which the viewer looks into the floating image display system is determined, it is advisable to arrange the image display device 1 and the second retroreflective member 5 in the retroreflective optical system with the angle θ2 = θ6 / 2. Furthermore, a predetermined interval L1 is required between the image display device 1 and the second retroreflective member 5 to enhance the cooling efficiency of the image display device 1. Additionally, it is necessary to define the interval L2 with respect to L1 in order to structurally obtain θ2 as described above.

[0024] The configuration of the floating image information display system of the present disclosure will be described more specifically. As shown in FIG. 6, it includes an image display device 1 that diverges image light of a specific polarization at a sandwiching angle and a second retroreflective member 5. The image display device 1 includes a liquid crystal display panel (hereinafter, may be simply referred to as a liquid crystal panel) 11 and a light source device 13 that generates light of a specific polarization having a sandwiching angle diffusion characteristic.

[0025] For the image light of a specific polarization from the image display device 1, an absorption type polarizing sheet 101 with an antireflection film provided on the surface is provided on the surface of the second retroreflective member 5 in contact with the outside of the device (not shown) to selectively transmit the image light of the specific polarization and absorb the other polarization included in the external light, thereby preventing the influence of the reflected light reflected on the surface of the second retroreflective member 5 on the floating image obtained.

[0026] Here, since the absorption type polarizing sheet 101 that selectively transmits the image light of a specific polarization has the property of transmitting the image light of the specific polarization, the image light of the specific polarization passes through the absorption type polarizing sheet 101. The transmitted image light forms a floating image 3 at a position symmetrical to the retroreflective member 5.

[0027] Note that the light forming the floating image 3 in the air is a set of light rays converging from the retroreflective member 5 to the optical image of the floating image 3, and these light rays continue to travel straight even after passing through the optical image of the floating image 3. Therefore, the floating image 3 is an image with high directivity, different from the diffused image light formed on a screen by a general projector or the like.

[0028] Therefore, in the configuration shown in FIG. 6, when viewed by the user from the direction shown in the figure, the floating image 3 in the air is viewed as a bright image, but when viewed by other people from the vertical and front-rear directions of the paper surface, the floating image 3 in the air cannot be viewed as an image at all. This characteristic is very suitable when adopted in a system for displaying images that require high security or highly confidential images that need to be concealed from the person facing the user.

[0029] Depending on the performance of the retroreflective member 5, the polarization axes of the image light after reflection may be uneven. In this case, some of the image light with uneven polarization axes is absorbed by the absorption-type polarizing sheet 101 described above. For this reason, unnecessary reflected light is not generated in the retroreflective optical system, and the degradation of the image quality of the floating image in space can be prevented or suppressed.

[0030] Also, in the floating image display device using the retroreflective optical system of the present disclosure, even when a monitor peeks into the floating image, the display screen of the image display device 1 is blocked by the reflecting surface of the retroreflective member 5. Therefore, compared with the case where the image display device 1 and the retroreflective member face each other directly, it is more difficult to view the display image of the image display device 1 directly.

[0031] <Configuration example of the second retroreflective optical system forming the floating image information display system> FIG. 7 is a diagram showing a main configuration of another example of a retro-optical system for realizing a floating image information display system according to an embodiment of the present invention. This floating image information display system is suitable for a monitor to observe the floating image from an obliquely upper direction. The image display device 1 includes a liquid crystal display panel 11 as an image 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 is composed of a small one with a screen size of about 5 inches to a large liquid crystal display panel exceeding 80 inches. The image light from the liquid crystal display panel 11 is emitted toward the retroreflective member (retroreflective portion or retroreflective plate) 5.

[0032] The liquid crystal panel 11 is made to receive light from a light source device 13 with a narrow divergence angle, which will be described later, to generate a video light beam with a narrow divergence angle and make it incident on the retroreflective member 5, thereby obtaining a spatial floating image 3. The spatial floating video 3 is formed at a symmetric position of the video display device 1 with the retroreflective member 5 as the symmetry plane. In order to eliminate the ghost image generated at this time and obtain a high-quality spatial floating video 3, it is advisable to provide a video light control sheet 334 with the structure shown in Fig. 12(A) on the emission side of the liquid crystal panel 11 to control the diffusion characteristics in unnecessary directions. Furthermore, since the reflectance of the reflective member such as the retroreflective member for the video light from the liquid crystal panel 11 can be increased in principle, it is advisable to use S-polarized light. However, when the viewer uses polarized sunglasses, the floating image in the air is reflected or absorbed by the polarized sunglasses. Therefore, as a countermeasure, a depolarizing element 339 is provided to optically convert a part of the video light of a specific polarization into the other polarization and pseudo-convert it into natural light, so that the viewer can monitor a good spatial floating video even when using polarized sunglasses. These are optically joined by an adhesive 338 so that no light reflection surface is generated and the image quality of the spatial floating image is not impaired.

[0033] Examples of commercially available depolarizing elements include Cosmo Shine SRF (manufactured by Toyobo Co., Ltd.) and depolarizing adhesive (manufactured by Nagase Sangyo Co., Ltd.). In the case of Cosmo Shine SRF (manufactured by Toyobo Co., Ltd.), by attaching an adhesive on the image display device, the reflection at the interface can be reduced and the luminance can be improved. Also, in the case of the depolarizing adhesive, it is used by bonding a colorless transparent plate and an image display device via the depolarizing adhesive. A video light control sheet 338 is also provided on the video emission surface of the retroreflective member 5 to eliminate the ghost images generated on both sides of the normal image of the spatial floating video 3 by unnecessary light. In this embodiment, the retroreflective member 5 is arranged parallel to the horizontal plane in space, and the spatial floating video 3 is configured to be displayed tilted by θ1 with respect to the horizontal plane. For this purpose, the display surface of the video display device 1 is configured to be tilted by θ1 on the side opposite to the spatial floating video 3 with respect to the horizontal plane. Furthermore, in this embodiment, the video display device 1 includes a light source device 13 that generates light of a specific polarization having diffusion characteristics with a sandwiching angle with the liquid crystal display panel 11.

[0034] <Configuration Example of the Third Retroreflective Optical System Forming the Spatial Floating Video Information Display System> FIG. 8 is a diagram showing another example of the configuration of the main part of the recursive optical system for realizing the spatial floating video information display system. This spatial video information display system is suitable for an observer to observe the spatial floating video from the front diagonally upward. 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 sandwiching angle diffusion characteristic. The liquid crystal display panel 11 is composed of a small one with a screen size of about 5 inches to a large liquid crystal display panel exceeding 80 inches.

[0035] The video light from the liquid crystal display panel 11 is emitted toward the retroreflective member 5. The liquid crystal panel 11 receives light from the light source device 13 having a narrow divergence angle described later, generates a video light beam with a narrow divergence angle, and makes it incident on the retroreflective member 5 to obtain the spatial floating image 3. The spatial floating video 3 is formed at the symmetric position of the video display device 1 with the retroreflective member 5 as the symmetric plane.

[0036] In order to eliminate the ghost image generated in the spatial floating image 3 and obtain a high-quality spatial floating video 3, a video light control sheet 334 may be provided on the emission side of the liquid crystal display panel 11 shown in FIG. 12(A) to control the diffusion characteristics in unnecessary directions. On the other hand, as shown in FIG. 12(B), a video light control sheet 338 may also be provided on the video emission surface of the retroreflective member 5 to eliminate the ghost images generated on both sides of the normal image of the spatial floating video 3 by unnecessary light. The retroreflective sheet 5 can generate the spatial floating image 3 at an angle of θ1 with respect to the horizontal plane by tilting (θ2) with respect to the horizontal plane. Therefore, for example, when the configuration of FIG. 8 is incorporated into the upper part of a KIOSK terminal and a spatial floating video is displayed as an avatar at the upper end portion of the terminal, the video light is directed toward the observer's eyes, so a high-brightness spatial floating video can be monitored.

[0037] In order to obtain the spatial floating video 3 at a desired elevation angle and position, similar to the first and second embodiments, the tilt angle θ2 of the retroreflective member 5, the tilt angle θ3 of the video display device 1, and their respective positions may be optimally designed.

[0038] <Configuration Example of the Fourth Retroreflective System Forming the Spatial Floating Video Information Display System> FIG. 9 is a diagram showing the main configuration of a recursive optical system of another example for realizing a spatial floating video information display system. This spatial video information display system is suitable for a viewer to observe a spatial floating video from an obliquely upper direction. 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 is composed of a small one with a screen size of about 5 inches to a large liquid crystal display panel exceeding 80 inches.

[0039] In order to obliquely incident the video light from the liquid crystal display panel 11 on the retroreflective member 5 arranged at a position facing the video light directly, it is preferable to arrange a linear Fresnel sheet 105 as shown in FIG. 10 as a video light control sheet 334 close to the video display surface of the liquid crystal panel 11 of the video display device 1 to refract the video light in a desired direction. At this time, a light shielding layer can be provided on the vertical surface of the linear Fresnel to suppress the generation of unnecessary light by blocking the incidence of video light from other than the Fresnel lens. Furthermore, by providing an antireflection film on the video light incident surface and the exit surface of the linear Fresnel sheet, the generation of unnecessary light can be suppressed and good characteristics can be obtained.

[0040] The video light control sheet 334 provided with the linear Fresnel sheet 105 described above emits light toward the retroreflective member 5. The liquid crystal panel 11 receives light from a light source device 13 having a narrow divergence angle described later to generate a video light beam with a narrow divergence angle and incident it on the retroreflective member 5 to obtain a spatial floating image 3. The spatial floating image 3 is formed at a symmetric position of the display surface of the video display device 1 with the retroreflective member 2 as the symmetric plane. In this embodiment, since the retroreflective member 2 and the video display device 1 are arranged at positions facing each other, when the viewer peeks into the retroreflective member 5 of the spatial floating video information display device, the video displayed on the liquid crystal panel 11 overlaps the spatial floating video, significantly degrading the image quality of the spatial floating video.

[0041] In order to prevent the above-described video light from overlapping with the floating image in space, a video light control sheet is provided on the video light emitting surface of the liquid crystal panel 11. As this video light control sheet, for example, the viewing angle control film (VCF) of Shin-Etsu Polymer Co., Ltd. is suitable. Since its structure is a sandwich structure in which transparent silicon and black silicon are alternately arranged and a synthetic resin is arranged on the light incident / emitting surface, the same effect as the external light control film of this embodiment can be expected. At this time, since the transparent silicon and black silicon extending in a predetermined direction are alternately arranged in the viewing angle control film (VFC), as shown in FIG. 11, the transparent silicon and black silicon of the video light control sheet 334 are inclined with respect to the vertical direction in the pixel arrangement direction of the liquid crystal panel 11 (θ10 in the figure), so that it is preferable to arrange it so as to reduce moire generated at the pitch between the pixels and the external light control film.

[0042] In the fourth embodiment, the retroreflective member 5 is arranged parallel to the bottom surface of the housing. As a result, external light enters the retroreflective member 5 and enters the inside of the housing, which causes a deterioration in the image quality of the floating image in space 3 generated. In order to eliminate the ghost image generated in the floating image 3 and obtain a high-quality floating image in space 3, similar to the second and third embodiments, as shown in FIGS. 12(A) and (B), a video light control sheet 334 may be provided on the emission side of the liquid crystal panel 11 to control the diffusion characteristics in unnecessary directions. On the other hand, a video light control sheet 338 may also be provided on the video emission surface of the retroreflective member 5 to eliminate ghost images generated on both sides of the normal image of the floating image in space 3 by unnecessary light. The structures described above are arranged inside the housing to prevent external light from entering the retroreflective member 5 and prevent the generation of ghost images.

[0043] <First Configuration Example of Floating Image Information Display System> FIG. 13 shows a first embodiment of a floating image information system using the four above-described retroreflective optical systems. The retroreflective member 5 is adhesively fixed or bonded to the transparent sheet 100. By making the structure such that the distance between the video display device 1 and the retroreflective member 5 can be variable and the imaging position of the floating image in space 3 can be variable, it is possible to give movement to the floating image in space, and a video information display device that can pseudo-display a three-dimensional floating image in space can be realized.

[0044] <Second Configuration Example of Spatial Floating Video Information Display System> A second embodiment of the spatial floating video information display system will be described with reference to FIG. 14. FIG. 14 shows an example in which the spatial floating video display device 202 is incorporated into a tablet terminal. The spatial floating video display device 202 and the flat panel display 200 are provided in the same housing 201, and a sensing unit 203 that covers all of the display images 204 of the flat panel display 200 and the spatial floating display 202 in the same plane as the airborne floating video 204 is provided at the starting point of the flat panel display 200 and the spatial floating video 204, and is provided in the same plane such as the sensing area 226. Further, when there are two or more of the sensing areas, they may exist parallel or front and back on the plane, or may exist on the same plane. The spatial floating video display device 202 and the flat panel display 200 may be provided side by side in the same housing 201. In this embodiment, the flat panel display 200 is used for explanation, but it is not limited to the flat panel display and any display may be used. In the second configuration example, this sensing area is at a higher position from the front of the device toward the rear and has a gradient. This realizes an arrangement that is easy to input. The sensing unit will be described in detail later.

[0045] In this video information display system, when the wavelength of the light source light of the TOF system, which is the ranging system of the sensing unit 203 used, is a long wavelength of 900 (nm) or more, it is less affected by external light. At this time, the user has an illusion that the spatial operation input performed on the displayed spatial floating video 204 can be similarly performed on the video display surface of the flat panel display 200. Therefore, the spatial operation input can be performed without directly touching the display screen of the flat panel display 200.

[0046] Furthermore, the inventors experimentally determined how far the planar display 200 and the sensing area 226 should be separated so that even if the operator performs a spatial operation based on the screen displayed on the planar display 200, the finger does not touch the surface of the planar display 200. As a result, it was experimentally found that by separating the imaging position of the spatial floating image 204 by 40 mm or more from the planar display 200, the probability that the operator directly touches the screen of the planar display 200 can be reduced to 50% or less. Furthermore, by separating it by 50 mm or more, the operation no longer directly touches the planar display 200.

[0047] Note that the configuration of FIG. 14 is not limited to the tablet terminal, and may be incorporated into various display devices such as ATMs, ticket vending machines, kiosk terminals, and stationary display devices.

[0048] <Third Configuration Example of Spatial Floating Image Information Display System> A third embodiment of the spatial floating video information display system will be described with reference to FIG. 15. FIG. 15 shows an example in which the spatial floating video display device 202 is incorporated into a tablet terminal. The spatial floating video display device 202 and the flat panel display 200 are provided in the same housing 201, and a first sensing unit 203a that senses a first sensing area (sensing region) 226a that covers the imaging area of the spatial floating video 204 of the spatial floating video display device 202, and a second sensing unit 203b that senses a second sensing area 226b that covers the image display area of the flat panel display 200. The first sensing area 226a and the second sensing area 226b are respectively provided at the starting points of the spatial floating video display device 202 and the flat panel display 200. Also, the first sensing area 226a and the second sensing area 226b are arranged in proximity. The first sensing area and the second sensing area exist parallel or front and back on a plane. As shown in FIG. 15, the first sensing area and the second sensing area may be configured to exist on the same plane. The spatial floating video display device 202 and the flat panel display 200 may be provided side by side in the same housing 201. In this embodiment, the flat panel display 200 is used for explanation, but it is not limited to the flat panel display, and any display may be used. In this example, it is arranged substantially parallel to the image display surface of the flat panel display 200. The sensing unit used here will also be described in detail later.

[0049] Also in the third embodiment of the video information display system described above, the user is made to have the illusion that the spatial operation input performed on the displayed spatial floating video 204 can be similarly performed on the video display surface of the flat panel display 200. For this reason, it is possible to perform a spatial operation input without directly touching the display screen of the flat panel display 200.

[0050] At this time, as a result of evaluating the contact of a finger with the flat display 200 using a prototype, the operator was able to perform a spatial operation input on the video information display system without directly touching the screen of the flat display 200 by separating the imaging position of the floating video 204 by 50 mm or more from the flat display 200.

[0051] Note that the configuration of FIG. 15 is not limited to a tablet terminal, and may be incorporated into various display devices such as an ATM, a ticket vending machine, a kiosk terminal, and a stationary display device.

[0052] <Technical means for sensing a spatial video> Since the monitor (operator) is connected bidirectionally to the information system via the floating video display device, the following description will be given of the sensing technology for pseudo-operating the floating video.

[0053] In the floating video information system, by reading the sensing information together with the floating video by a two-dimensional sensor described later, an image operation on the display video can be enabled.

[0054] In order for a monitor (operator) to be bidirectionally connected to an information system via a spatial floating image display device, the sensing technology for pseudo-operating a spatial floating image will be described below. FIG. 16 is a principle diagram for explaining the sensing technology. A distance measuring device 203 incorporating a TOF (Time of Flight) system corresponding to the spatial floating image is provided. An LED (Light Emitting Diode) that emits near-infrared light as a light source is caused to emit light in synchronization with the signal of the system. An optical element for controlling the divergence angle is provided on the light emission side of the light beam of the LED, and a pair of highly sensitive avalanche diodes having a picosecond time resolution is used as light receiving elements, and they are arranged in alignment in the horizontal direction so as to correspond to the area. The phase Δt is shifted by the time from when the LED, which is the light source, emits light in synchronization with the signal from the system until it is reflected by the object to be distance-measured (the tip of the operator's finger) and returns to the light receiving part. The distance of the object is calculated from this time difference Δt, and the position and movement of the operator's finger are sensed as two-dimensional information in combination with the position information of a plurality of sensors arranged in parallel. Further, a spatial floating information display system or a spatial floating image display device having a sensing function with less false detection for the display screen of a flat panel display and the spatial floating image can be realized.

[0055] <Technical means for reducing ghost images> The technical means for realizing a high-quality spatial image display device with reduced ghost images as a spatial floating image display device will be described with reference to FIG. 12. In order to control the divergence angle of the video light from the liquid crystal panel 13 as a video display element to a desired direction, it is preferable to provide a video light control sheet 334 on the emission surface of the liquid crystal panel 13. Further, the video light control sheet 334 is provided on the light emission surface or the light incident surface or both surfaces of the retroreflective member to absorb abnormal light that generates ghost images.

[0056] FIG. 12 shows a specific method of applying the video light control sheet 334 to a spatial image display device. The video light control sheet 334 is provided on the emission surface of the liquid crystal panel 335 which is a video display element. At this time, in order to reduce moire generated by the interference due to the pitch of the pixels of the liquid crystal panel 13, the transmission part 336 and the light absorption part 337 of the video light control sheet 334, the following two methods are effective.

[0057] (1) The transmission part and the longitudinal stripes generated by the light absorption part of the image light control sheet 334 are arranged with an inclination of θ10 as shown in FIG. 11 with respect to the pixel arrangement of the liquid crystal panel 335 (denoted as the liquid crystal panel 11 in FIG. 11).

[0058] (2) When the pixel size of the liquid crystal panel 335 is A and the pitch of the longitudinal stripes of the image light control sheet 334 is B, this ratio (B / A) is selected so as to deviate from an integral multiple.

[0059] One pixel 339 of the liquid crystal panel is composed of three pixels of RGB arranged in parallel and is generally square. Therefore, it is impossible to suppress the occurrence of moiré over the entire screen. For this reason, it was experimentally determined that the inclination θ10 shown in (1) should be optimized within the range of 5 degrees to 25 degrees so that the occurrence position of moiré can be intentionally shifted to a place where no floating image is displayed. Although the liquid crystal panel was described as a material for reducing moiré, the moiré generated between the retroreflective member 5 and the image light control sheet 334 can be reduced by optimally inclining the image light control sheet with respect to the X-axis as shown in FIG. 4 because both are linear structures, and large-scale moiré with a low frequency that can be visually recognized even with a long wavelength can be reduced.

[0060] FIG. 12(A) is a vertical cross-sectional view of the image display device 1 of the present invention in which the image light control sheet 334 is arranged on the image light emitting surface of the liquid crystal panel 335. The image light control sheet 334 is configured by alternately arranging a light transmission part 336 and a light absorption part 337 and is adhesively fixed to the image light emitting surface of the liquid crystal panel 335 by an adhesive layer 338.

[0061] Also, as described above, when using a 7-inch WUXGA (1920×1200 pixels) liquid crystal display panel as the video display device 1, even if one pixel (one triplet) (A in the figure) is about 80 μm, for example, if the pitch B consisting of a transmission part d2 of 300 μm and a light absorption part d1 of 40 μm of the video light control sheet 334 is 340 μm, sufficient transmission characteristics can be achieved, and the diffusion characteristics of the video light from the video display device that causes abnormal light can be controlled to reduce the ghost images generated on both sides of the spatial floating image. At this time, if the thickness of the video control sheet is 2 / 3 or more of the pitch B, the ghost reduction effect is significantly improved.

[0062] Figure 12(B) is a vertical cross-sectional view of the retroreflective member of the present invention in which the video light control sheet 334 is disposed on the video light emitting surface of the retroreflective member 5. The video light control sheet 334 is configured by alternately arranging a light transmission part 336 and a light absorption part 337, and is inclinedly arranged with an inclination angle θ1 in accordance with the emission direction of the retroreflected light. As a result, the abnormal light generated due to the above-described retroreflection can be absorbed, and on the other hand, the normal reflected light can be transmitted without loss.

[0063] When using a 7-inch WUXGA (1920×1200 pixels) liquid crystal display panel, even if one pixel (one triplet) (A in the figure) is about 80 μm, for example, if the pitch B consisting of a transmission part d2 of 400 μm and a light absorption part d1 of 20 μm of the retroreflective part is 420 μm, sufficient transmission characteristics can be achieved, and the diffusion characteristics of the video light from the video display device that causes abnormal light in the retroreflective member can be controlled to reduce the ghost images generated on both sides of the spatial floating image.

[0064] On the other hand, the above-described video light control sheet 334 also helps to improve the reliability of the components because it prevents external light from the outside from entering the spatial floating video display device. As this video light control sheet, for example, the viewing angle control film (VCF) of Shin-Etsu Polymer Co., Ltd. is suitable. Since its structure is a sandwich structure in which transparent silicon and black silicon are alternately arranged and a synthetic resin is arranged on the light input / output surface, the same effect as the external light control film of this embodiment can be expected.

[0065] <Performance of liquid crystal panel> Incidentally, in a general TFT (Thin Film Transister) liquid crystal panel, the luminance and contrast performance vary depending on the characteristics of the liquid crystal and polarizing plate according to the light emission direction. In the evaluation in the measurement environment shown in FIG. 29, the characteristics of luminance and viewing angle in the short side (vertical) direction of the panel are superior at an angle slightly deviated from the emission angle perpendicular to the panel surface (emission angle 0 degrees) as shown in FIG. 31 (in this embodiment, +5 degrees). This is because the light-twisting characteristic in the short side (vertical) direction of the liquid crystal panel does not become 0 degrees when the applied voltage is maximum.

[0066] On the other hand, as shown in FIG. 33, the contrast performance in the short side (vertical) direction of the panel is excellent in the range of -15 degrees to +15 degrees. When combined with the luminance characteristic, the best characteristics can be obtained in the range of ±10 degrees centered on 5 degrees.

[0067] Also, as shown in FIG. 30, the characteristics of luminance and viewing angle in the long side (horizontal) direction of the panel are excellent at the emission angle perpendicular to the panel surface (emission angle 0 degrees). This is because the light-twisting characteristic in the long side (horizontal direction) of the liquid crystal panel becomes 0 degrees when the applied voltage is maximum.

[0068] Similarly, as shown in FIG. 32, the contrast performance in the long side (horizontal) direction of the panel is excellent in the range of -5 degrees to -10 degrees. When combined with the luminance characteristic, the best characteristics can be obtained in the range of ±5 degrees centered on -5 degrees. Therefore, the emission angle of the video light emitted from the liquid crystal panel is made to be incident on the liquid crystal panel from the direction where the best characteristics can be obtained by the light beam direction conversion means (reflective surfaces 307, 314, etc.) provided in the light guide body of the light source device 13 described above, and the light is modulated by the video signal, which improves the image quality and performance of the video display device 1.

[0069] In order to maximize the luminance and contrast characteristics of the liquid crystal panel as a video display element, the video quality of the floating video can be improved by setting the incident light from the light source to the liquid crystal panel within the above-described range.

[0070] <Method for Controlling Light Source Light> In this embodiment, in order to improve the utilization efficiency of the emitted light beam from the light source device 13 and significantly reduce the power consumption, in the video display device 1 including the light source device 13 and the liquid crystal display panel 11, after the light beam from the light source device 13 is incident on the liquid crystal display panel 11 at an incident angle that maximizes the characteristics of the liquid crystal panel 11, a video light beam that is luminance-modulated according to the video signal is emitted toward the retroreflective member. At this time, in order to reduce the size of the set volume of the spatial floating video information display system, it is desired to increase the degree of freedom in arranging the liquid crystal display panel 11 and the retroreflective member. Further, in order to form a floating video at a desired position and ensure optimal directivity after retroreflection, the following technical means are used.

[0071] On the video display surface of the liquid crystal display panel 11, a transparent sheet made of an optical component such as a linear Fresnel lens shown in FIG. 10 is provided as a light direction conversion panel to control the emission direction of the incident light beam to the retroreflective optical member while imparting high directivity, thereby determining the imaging position of the spatial floating video. According to this, the video light from the video display device 1 can efficiently reach the observer with high directivity (straightness) like laser light. As a result, it is possible to display a high-quality floating video with high resolution and significantly reduce the power consumption of the video display device 1 including the light source device 13.

[0072] <Example 1 of video display device> FIG. 22 shows another example of the specific configuration of the video display device 1. The light source device 13 in FIG. 22 is the same as the light source device in FIGS. 23 and the like. This light source device 13 is configured by housing an LED, a collimator, a composite diffusion block, a light guide, etc. in a case made of, for example, plastic, and the liquid crystal display panel 11 is attached to its upper surface. In addition, 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, which is a member for cooling the heat generated by the LED elements and the control circuit, is attached (not shown in the figure).

[0073] In addition, on the liquid crystal display panel frame attached to the upper surface of the case, 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 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 that are solid light sources, modulates the intensity of transmitted light based on a control signal from a control circuit (not shown here) that constitutes the electronic device, thereby generating a display image.

[0074] <Example 1 of the light source device of Example 1 of the video display device> Subsequently, the configuration of the optical system such as the light source device housed in the case will be described in detail with reference to FIGS. 22(a) and (b) together with FIG. 21. FIGS. 21 and 22 show the LEDs 14a and 14b that constitute the light source, and these are attached to the collimator 15 at predetermined positions. The collimator 15 is formed of a light-transmissive resin such as acrylic, for example. As shown in FIG. 22(b), the collimator 15 has a conical convex outer peripheral surface 156 obtained by rotating a parabolic cross section, and has a concave portion 153 formed with a convex portion (i.e., a convex lens surface) 157 at the center of its top (the side in contact with the LED substrate).

[0075] In addition, at the center of the flat surface portion (the side opposite to the above-mentioned top) of the collimator 15, it has a convex lens surface (or it may be a concave lens surface recessed inward) 154 protruding outward. The parabolic surface 156 forming the conical outer peripheral surface of the collimator 15 is set within a range of angles that can totally reflect the light emitted from the LEDs 14a and 14b in the peripheral direction inside it, or a reflecting surface is formed.

[0076] Also, the LEDs 14a and 14b are respectively arranged at predetermined positions on the surface of the substrate 102, which is their circuit board. This substrate 102 is arranged and fixed with respect to the collimator 15 such that the LEDs 14a or 14b on its surface are respectively positioned at the central portions of the concave portions 153 thereof.

[0077] According to such a configuration, among the light emitted from the LED 14a or 14b, particularly the light emitted upward (rightward in the figure) from the central portion thereof, is condensed by the two convex lens surfaces 157 and 154 forming the outer shape of the collimator 15 to become parallel light. Also, 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 15 and is similarly condensed to become parallel light. In other words, according to the collimator 15 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 14a or 14b can be taken out as parallel light, and it becomes possible to improve the utilization efficiency of the generated light.

[0078] Note that a polarization conversion element 21 is provided on the light emission side of the collimator 15. The polarization conversion element 21 may also be referred to as a polarization conversion member. As is clear from FIG. 22(a), this polarization conversion element 21 is configured by combining a columnar (hereinafter, parallelogram column) light-transmissive member having a parallelogram cross section and a columnar (hereinafter, triangular column) light-transmissive member having a triangular cross section, and is arranged in an array of a plurality of them parallel to the plane orthogonal to the optical axis of the parallel light from the collimator 15. Further, a polarization beam splitter (hereinafter, abbreviated as "PBS film") 211 and a reflection film 212 are alternately provided at the interfaces between the adjacent light-transmissive members arranged in this array. Also, a λ / 2 phase plate 213 is provided on the emission surface from which the light that has entered the polarization conversion element 21 and passed through the PBS film 211 is emitted.

[0079] On the exit surface of this polarization conversion element 21, a rectangular composite diffusion block 16 shown in Fig. 22(a) is further provided. That is, the light emitted from the LED 14a or 14b becomes parallel light by the action of the collimator 15 and enters the composite diffusion block 16, and after being diffused by the texture 161 on the exit side, it reaches the light guide 17.

[0080] The light guide 17 is a member formed in a rod shape with a substantially triangular cross section (see Fig. 23(b)) by a light-transmissive resin such as acrylic. And as is also clear from Fig. 25, a light guide light incident portion (surface) 171 facing the exit surface of the composite diffusion block 16 via the first diffusion plate 18a, a light guide light reflection portion (surface) 172 forming an inclined surface, and a light guide light exit portion (surface) 173 facing the liquid crystal display panel 11, which is a liquid crystal display element, via the second diffusion plate 18b are provided.

[0081] On the light guide light reflection portion (surface) 172 of this light guide 17, as shown in Fig. 23 which is a partial enlarged view thereof, a large number of reflecting surfaces 172a and connecting surfaces 172b are alternately formed in a serrated shape. And the reflecting surface 172a (the line segment rising to the upper right in the figure) forms αn (n is a natural number, and in this example, for example, it is 1 to 130) with respect to the horizontal plane shown by the dashed-dotted line in the figure. As an example, here, αn is set to 43 degrees or less (however, 0 degrees or more).

[0082] The light guide incident portion (surface) 171 is formed in a curved convex shape inclined toward the light source side. According to this, the parallel light from the exit surface of the composite diffusion block 16 is diffused and incident via the first diffusion plate 18a, and as is clear from the figure, it reaches the light guide light reflection portion (surface) 172 while being slightly bent (deflected) upward by the light guide incident portion (surface) 171, and is reflected here and reaches the liquid crystal display panel 11 provided on the upper exit surface of the figure.

[0083] According to the video display device 1 described in detail above, it is possible to further improve the light utilization efficiency and its uniform illumination characteristics, and at the same time, it is possible to manufacture it in a small size and at low cost, including the modularized light source device of the S-polarized light wave. In the above description, the polarization conversion element 21 is described as being attached after the collimator 15. However, the present invention is not limited thereto, and the same operation and effect can be obtained by providing it in the optical path leading to the liquid crystal display panel 11.

[0084] Note that a large number of reflecting surfaces 172a and connecting surfaces 172b are alternately formed in a sawtooth shape on the light guide light reflecting portion (surface) 172. The illumination light beam is totally reflected on each reflecting surface 172a and goes upward. Further, a sandwiching angle diffusion plate is provided on the light guide light emitting portion (surface) 173, and the illumination light beam enters the light direction conversion panel 54 for adjusting the directivity characteristics as a substantially parallel diffused light beam, and enters the liquid crystal display panel 11 from an oblique direction. In this embodiment, the light direction conversion panel 54 is provided between the light guide light emitting surface 173 and the liquid crystal display panel 11. However, the same effect can be obtained even if it is provided on the light emitting surface of the liquid crystal display panel 11.

[0085] The light emitted from the liquid crystal display panel 11 has mutually similar diffusion characteristics in the horizontal direction of the screen (the display direction corresponding to the X axis of the graph in FIG. 28(A)) and the vertical direction of the screen (the display direction corresponding to the Y axis of the graph in FIG. 28(B)), as shown by the plot curves of "conventional characteristics (X direction)" in FIG. 28(A) and "conventional characteristics (Y direction)" in FIG. 28(B) in a general TV application device.

[0086] On the other hand, the diffusion characteristics of the light beam emitted from the liquid crystal display panel of this embodiment are diffusion characteristics as shown by the plot curves of "Example 1 (X direction)" in FIG. 28(A) and "Example 1 (Y direction)" in FIG. 28(B).

[0087] In one specific example, when the viewing angle at which the luminance becomes 50% of the luminance in the front view (angle 0 degrees) (luminance reduced to about half) is set to 13 degrees, it becomes an angle of about 1 / 5 with respect to the diffusion characteristics (angle 62 degrees) of a general household TV device. Similarly, in an example where the viewing angles in the vertical direction are unevenly set between the upper side and the lower side, the reflection angle of the reflective light guide, the area of the reflection surface, etc. are optimized so that the upper viewing angle is suppressed (narrowed) to about 1 / 3 with respect to the lower viewing angle.

[0088] By setting the viewing angle and the like as described above, compared with a conventional liquid crystal TV, the amount of light of the video heading toward the viewing direction of the user increases significantly (greatly improving in terms of the brightness of the video), and the luminance of such a video becomes 50 times or more.

[0089] Furthermore, when the viewing angle characteristics shown in "Example 2" of FIG. 28 are used, when the viewing angle at which the luminance becomes 50% of the luminance of the video obtained in the front view (angle 0 degrees) (luminance reduced to about half) is set to 5 degrees, it becomes an angle of about 1 / 12 (narrow viewing angle) with respect to the diffusion characteristics (angle 62 degrees) of a general household TV device. Similarly, in an example where the viewing angles in the vertical direction are evenly set between the upper side and the lower side, the reflection angle of the reflective light guide, the area of the reflection surface, etc. are optimized so that such a vertical viewing angle is suppressed (narrowed) to about 1 / 12 with respect to the conventional one.

[0090] By making such a setting, compared with a conventional liquid crystal TV, the luminance (amount of light) of the video heading toward the viewing direction (the line-of-sight direction of the user) is greatly improved, and the luminance of such a video becomes 100 times or more.

[0091] As described above, by using the viewing angle as the included angle, the amount of light flux heading toward the viewing direction can be concentrated, so the light utilization efficiency is greatly improved. As a result, even when using a liquid crystal display panel for general TV use, by adjusting the light diffusion characteristics of the light source device, it is possible to achieve a significant increase in luminance with the same power consumption, and it can be made into a video display device corresponding to an information display system for a bright outdoor environment.

[0092] When using a large liquid crystal display panel, the light around the screen is directed inward so that when the viewer faces the center of the screen, it heads in the direction of the viewer, thereby improving the overall uniformity of the screen brightness. FIG. 25 shows the convergence angles of the long side and the short side of the liquid crystal display panel with respect to the distance L from the liquid crystal display panel to the viewer and the panel size of the video display device (screen ratio 16:10) as parameters.

[0093] In the figure shown above FIG. 25, it is assumed that the screen of the liquid crystal display panel is vertically long (hereinafter also referred to as "vertical use") and the video is viewed. In this case, the convergence angle may be set according to the short side of the liquid crystal display panel (refer to the direction of arrow V in FIG. 25 as appropriate). As a more specific example, as can be seen from the plot graph in FIG. 15, for example, when viewing a 22" panel in vertical use at a viewing distance of 0.8 m, by setting the convergence angle to 10 degrees, the video light from each corner (4 corners) of the screen can be effectively projected or output toward the viewer.

[0094] Similarly, when viewing a 15" panel in vertical use at a viewing distance of 0.8 m, if the convergence angle is set to 7 degrees, the video light from the 4 corners of the screen can be effectively directed toward the viewer. As described above, by directing the video light around the screen according to the size of the liquid crystal display panel and whether it is vertical use or horizontal use toward the viewer who is at the optimal position for viewing the center of the screen, the overall uniformity of the screen brightness can be improved.

[0095] As a basic configuration, as shown in FIG. 26 etc. described above, a light beam with a sandwiching angle and directivity characteristics 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 reflected by the retroreflective member are displayed outdoors or indoors through the transparent member 100.

[0096] Hereinafter, a plurality of examples of another example of the light source device will be described. Any of these other examples of the light source device may be adopted in place of the light source device in the example of the video display device described above.

[0097] When using a large liquid crystal display panel, as described above, the light around the screen is directed inward so that it faces the viewer's direction when the viewer is facing the center of the screen, improving the overall screen brightness. On the other hand, binocular disparity occurs depending on which of the viewer's left and right eyes is used for viewing. FIG. 26 shows the convergence angles of the long side and the short side of the liquid crystal display panel with respect to the distance L from the liquid crystal display panel to the viewer and the panel size (screen ratio 16:10) of the video display device, with the positions of the left and right eyes as reference.

[0098] The smaller the panel size and the closer the monitoring distance, the larger the convergence angle due to binocular vision by the left and right eyes. Especially when using a small panel of 7 inches or less, the convergence angle due to binocular disparity becomes an important requirement. For example, for a panel of 7 inches or less, the light diffusion characteristics or the directivity characteristics of the light source shown in FIG. 28 are expanded or designed to have directivity characteristics so that the video light is directed to the optimal monitoring range of the system.

[0099] Furthermore, in order to obtain the horizontal and vertical directivity characteristics and diffusion characteristics according to the system requirements, it is necessary to optimally design the shape, surface roughness, inclination, etc. of the reflecting surface of the light guide body of the light source device 13 described above.

[0100] <Example 1 of Light Source Device> Next, with reference to FIG. 17, another example of the light source device will be described. FIGS. 17(a) and (b) are diagrams in which a part of the liquid crystal display panel 11 and the diffusion plate 206 are omitted for explaining the light guide body 311.

[0101] FIG. 17 shows a state in which the LEDs 14 constituting the light source are provided on the substrate 102. These LEDs 14 and the substrate 102 are attached to the reflector 15 at predetermined positions.

[0102] As shown in FIG. 17(a), the LEDs 14 are arranged in a row in a direction parallel to the side (the short side in this example) of the liquid crystal display panel 11 on the side where the reflector 300 is arranged. In the illustrated example, the reflector 300 is arranged corresponding to such an arrangement of the LEDs. Note that a plurality of reflectors 300 may be arranged.

[0103] In a specific example, each of the reflectors 300 is formed of a plastic material. As another example, the reflector 300 may be formed of a metal material or a glass material, but since the plastic material is easier to mold, the plastic material is used in this embodiment.

[0104] As shown in FIG. 17(b), the inner surface (the right side in the figure) of the reflector 300 includes a reflecting surface 305 having a shape obtained by cutting a paraboloid by a meridian plane (hereinafter may be referred to as a "paraboloid"). The reflector 300 reflects the divergent light emitted from the LED 14 by the above-described reflecting surface 305 (paraboloid) to convert it into substantially parallel light, and makes the converted light incident on the end surface of the light guide 311. In a specific example, the light guide 311 is a transmissive light guide.

[0105] The reflecting surface of the reflector 300 has a shape asymmetric with respect to the optical axis of the light emitted from the LED 14. Further, the reflecting surface 305 of the reflector 300 is a paraboloid as described above, and by arranging the LED at the focus of such a paraboloid, the light beam after reflection is converted into substantially parallel light.

[0106] Since the LED 14 is a surface light source, even if it is arranged at the focus of the paraboloid, the divergent light from the LED cannot be completely converted into parallel light, but this does not affect the performance of the light source of the present invention. The LED 14 and the reflector 300 are a pair, and in order to ensure a predetermined performance with an attachment accuracy of ±40 μm of the LED 14 to the substrate 102, the attachment of the LED substrate should be 10 or less at most, and it is preferable to suppress it to about 5 in consideration of mass productivity.

[0107] Although the LED 14 and the reflector 300 are in proximity in part, heat can be dissipated into the space on the opening side of the reflector 300, so that the temperature rise of the LED can be reduced. For this reason, the plastic molded reflector 300 can be used. As a result, the shape accuracy of the reflecting surface can be improved by more than 10 times compared with that of the reflector made of glass material, so that the light utilization efficiency can be improved.

[0108] On the other hand, a reflecting surface is provided on the bottom surface 303 of the light guide 311. The light from the LED 14 is converted into a parallel light beam by the reflector 300, then reflected by the reflecting surface, and emitted toward the liquid crystal display panel 11 arranged to face the light guide 311. As shown in FIG. 17, the reflecting surface provided on the bottom surface 303 may have a plurality of surfaces with different inclinations in the traveling direction of the parallel light beam from the reflector 300. Each of the plurality of surfaces with different inclinations may have a shape extending in a direction perpendicular to the traveling direction of the parallel light beam from the reflector 300.

[0109] Further, the shape of the reflecting surface provided on the bottom surface 303 may be a planar shape. At this time, the refracting surface 314 provided on the surface of the light guide 311 facing the liquid crystal display panel 11 refracts the light reflected by the reflecting surface provided on the bottom surface 303 of the light guide 311, and highly accurately adjusts the amount of light and the emission direction of the light beam toward the liquid crystal display panel 11.

[0110] As shown in FIG. 17, the refracting surface 314 may have a plurality of surfaces with different inclinations in the traveling direction of the parallel light beam from the reflector 300. Each of the plurality of surfaces with different inclinations may have a shape extending in a direction perpendicular to the traveling direction of the parallel light beam from the reflector 300. The inclination of the plurality of surfaces refracts the light reflected by the reflecting surface provided on the bottom surface 303 of the light guide 311 toward the liquid crystal display panel 11. Further, the refracting surface 314 may be a transmissive surface.

[0111] In addition, when there is a diffusion plate 206 in front of the liquid crystal display panel 11, the light reflected by the reflection surface is refracted toward the diffusion plate 206 due to the plurality of inclinations of the refraction surface 314. That is, the extending directions of the plurality of surfaces having different inclinations of the refraction surface 314 and the extending directions of the plurality of surfaces having different inclinations of the reflection surface provided on the bottom surface 303 are parallel. By making the extending directions of both parallel, the light angle can be adjusted more preferably. On the other hand, the LED 14 is soldered to the metallic substrate 102. Therefore, the heat generated by the LED can be dissipated into the air through the substrate.

[0112] Also, the reflector 300 may be in contact with the substrate 102, or a space may be left. When leaving a space, the reflector 300 is adhesively disposed on the housing. By leaving a space, the heat generated by the LED can be dissipated into the air, and the cooling effect is improved. As a result, the operating temperature of the LED can be reduced, so that the maintenance of the luminous efficiency and the extension of the service life are realized.

[0113] <Another example 2 of the light source device> Subsequently, regarding the optical system configuration of a light source device in which the light utilization efficiency is improved 1.8 times using polarization conversion with respect to the light source device shown in FIG. 17, it will be described in detail with reference to FIGS. 18A, 18B, 18C7C, and 18D. Note that the illustration of the sub-reflector 308 is omitted in FIG. 18A.

[0114] FIGS. 18, 18B, and 18C show a state in which the LEDs 14 constituting the light source are provided on the substrate 102, and these are configured by a unit 312 having a reflector 300 and the LEDs 14 as a pair of blocks and having a plurality of blocks.

[0115] Among these, the base material 320 shown in FIG. 18A(2) is the base material of the substrate 102. Generally, since the metallic substrate 102 has heat, in order to insulate (heat-insulate) the heat of such a substrate 102, it is preferable to use a plastic material or the like for the base material 320. The material of the reflector 300 and the shape of the reflection surface may be the same material and shape as those in the example of the light source device in FIG. 26.

[0116] Further, the reflecting surface of the reflector 300 may have a shape asymmetric with respect to the optical axis of the light emitted from the LED 14. The reason for this will be described with reference to Fig. 18A(2). In this embodiment, similar to the example of Fig. 17, the reflecting surface of the reflector 300 is a paraboloid, and the center of the light emitting surface of the LED, which is a surface light source, is arranged at the focal position of the paraboloid.

[0117] Also, due to the characteristics of the paraboloid, the light emitted from the four corners of the light emitting surface also becomes a substantially parallel light beam, and only the emission direction is different. Therefore, even if the light emitting part has an area, if the distance between the polarization conversion element arranged in the subsequent stage and the reflector 300 is short, the amount of light incident on the polarization conversion element 21 and the conversion efficiency are hardly affected.

[0118] In addition, even if the mounting position of the LED 14 is displaced within the XY plane with respect to the focal point of the corresponding reflector 300, an optical system can be realized that can reduce the decrease in light conversion efficiency for the reasons described above. Furthermore, even when the mounting position of the LED 14 varies in the Z-axis direction, the converted parallel light beam only moves within the ZX plane, and the mounting accuracy of the LED, which is a surface light source, can be significantly reduced. In this embodiment as well, the reflector 300 having a reflecting surface obtained by meridionally notching a part of the paraboloid has been described, but an LED may be arranged on a part obtained by notching the entire paraboloid as the reflecting surface.

[0119] On the other hand, in this embodiment, as shown in Fig. 18B(1) and Fig. 18C, the divergent light from the LED 14 is reflected by the paraboloid 321 and converted into substantially parallel light, and then incident on the end face of the subsequent polarization conversion element 21, and the polarization conversion element 21 aligns it to a specific polarization state. With this characteristic configuration, in the present invention, the light utilization efficiency becomes 1.8 times that of the example of Fig. 26 described above, and a highly efficient light source can be realized.

[0120] At this time, the substantially parallel light obtained by reflecting the divergent light from the LED 14 by the paraboloid 321 is not all uniform. Therefore, by adjusting the angular distribution of the reflected light by the reflecting surface 307 having a plurality of inclinations, it is possible to make the light incident on the liquid crystal display panel 11 in a direction perpendicular to the liquid crystal display panel 11.

[0121] Here, in the example of this figure, the light (main light ray) entering the reflector from the LED and the light entering the liquid crystal display panel are arranged to be substantially parallel. This arrangement is easy to arrange in terms of design, and it is preferable to arrange the heat source under the light source device because air can escape upward, reducing the temperature rise of the LED.

[0122] Also, as shown in Fig. 18B(1), in order to improve the capture rate of the divergent light from the LED14, the light beam that cannot be captured by the reflector 300 is reflected by the sub-reflector 308 provided on the light-shielding plate 309 arranged above the reflector, and then reflected by the inclined surface of the lower sub-reflector 310 and incident on the effective area of the subsequent polarization conversion element 21 to further improve the light utilization efficiency. That is, in this embodiment, a part of the light reflected by the reflector 300 is reflected by the sub-reflector 308, and the light reflected by the sub-reflector 308 is reflected by the sub-reflector 310 in the direction toward the light guide 306.

[0123] The substantially parallel light beam aligned in a specific polarization by the polarization conversion element 21 is reflected toward the liquid crystal display panel 11 arranged to face the light guide 306 by the reflection shape provided on the surface of the reflection type light guide 306. At this time, the light quantity distribution of the light beam incident on the liquid crystal display panel 11 is optimally designed according to the shape and arrangement of the reflector 300, the reflection surface shape (cross-sectional shape) of the reflection type light guide, the inclination of the reflection surface, and the surface roughness described above.

[0124] As the reflection surface shape provided on the surface of the light guide 306, a plurality of reflection surfaces are arranged to face the light-emitting surface of the polarization conversion element, and the inclination, area, height, and pitch of the reflection surface are optimized according to the distance from the polarization conversion element 21, so that, as described above, the light quantity distribution of the light beam incident on the liquid crystal display panel 11 is set to a desired value.

[0125] As shown in Fig. 18B(2), the reflecting surface 307 provided on the reflective light guide can be configured to have a plurality of inclinations on one surface, so that the adjustment of the reflected light can be realized with higher precision. In the reflecting surface, as a configuration having a plurality of inclinations on one surface, the area used as the reflecting surface may be a plurality of surfaces, or a multi-surface, or a curved surface. Furthermore, due to the diffusion effect of the diffusion plate 206, a more uniform light quantity distribution is realized. The light incident on the diffusion plate closer to the LED realizes a uniform light quantity distribution by changing the inclination of the reflecting surface.

[0126] In this embodiment, the base material of the reflecting surface 307 uses a plastic material such as heat-resistant polycarbonate. Also, the angle of the reflecting surface 307 immediately after the emission of the λ / 2 plate 213 changes depending on the distance between the λ / 2 plate and the reflecting surface.

[0127] Also in this embodiment, although the LED 14 and the reflector 300 are close to each other in part, heat can be dissipated to the space on the opening side of the reflector 300, and the temperature rise of the LED can be reduced. Further, the substrate 102 and the reflector 300 may be arranged upside down as shown in Figs. 18A, 18B, and 18C.

[0128] However, if the substrate 102 is arranged upward, the substrate 102 will be close to the liquid crystal display panel 11, so the layout may become difficult. Therefore, as shown in the figure, it is better to arrange the substrate 102 below the reflector 300 (the side far from the liquid crystal display panel 11), so that the configuration inside the device becomes simpler.

[0129] A light shielding plate 410 may be provided on the light incident surface of the polarization conversion element 21 so that unnecessary light for the subsequent optical system does not enter. By adopting such a configuration, a light source device with suppressed temperature rise can be realized. In the polarizing plate provided on the light incident surface of the liquid crystal display panel 11, the temperature rise is reduced by absorption in the light beam with uniform polarization of the present invention. However, when reflected by the reflective light guide, the polarization direction rotates and part of the light is absorbed by the incident-side polarizing plate. Furthermore, although the temperature of the liquid crystal display panel 11 also rises due to the absorption in the liquid crystal itself and the temperature rise caused by the light incident on the electrode pattern, there is sufficient space between the reflecting surface of the reflective light guide 306 and the liquid crystal display panel 11, enabling natural cooling.

[0130] Figure 18D is a modified example of the light source device of FIGS. 18B(1) and 18C. FIG. 18D(1) illustrates a modified example by extracting a part of the light source device of FIG. 18B(1). Since the other configurations are the same as those of the light source device described above with reference to FIG. 18B(1), illustration and repeated description are omitted.

[0131] First, in the example shown in FIG. 18D(1), the height of the concave portion 319 of the sub-reflector 310 is adjusted so that the principal ray of the fluorescence output laterally (in the X-axis direction) from the phosphor 114 (refer to the straight line extending in the direction parallel to the X-axis in FIG. 18D(1)) is lower than the phosphor 114 so as to pass through the concave portion 319 of the sub-reflector 310. Further, the height of the light shielding plate 410 is adjusted to be lower in the Z-axis direction with respect to the position of the phosphor 114 so that the principal ray of the fluorescence output laterally from the phosphor 114 enters the effective region of the polarization conversion element 21 without being blocked by the light shielding plate 410.

[0132] In addition, the reflecting surface of the convex portion of the unevenness at the top of the sub-reflector 310 reflects the light reflected by the sub-reflector 308 in order to guide the light reflected by the sub-reflector 308 to the light guide 306. Therefore, the height of the convex portion 318 of the sub-reflector 310 is adjusted so as to reflect the light reflected by the sub-reflector 308 and make it enter the effective region of the subsequent polarization conversion element 21, whereby the light utilization efficiency can be further improved.

[0133] Note that the sub-reflector 310 is arranged to extend in one direction as shown in FIG. 18A(2) and has an uneven shape. Further, at the top of the sub-reflector 310, unevenness having one or more concave portions are arranged periodically along one direction. By adopting such an uneven shape, the principal ray of the fluorescence output laterally from the phosphor 114 can be configured to enter the effective region of the polarization conversion element 21.

[0134] In addition, the concavo-convex shape of the sub-reflector 310 is periodically arranged at a pitch where the concave portion 319 comes to the position where the LED 14 is located. That is, each of the phosphors 114 is periodically arranged along one direction corresponding to the pitch of the arrangement of the concave portions of the concavo-convex of the sub-reflector 310. When the phosphor 114 is provided in the LED 14, the phosphor 114 may be expressed as the light-emitting portion of the light source.

[0135] In addition, FIG. 18D(2) illustrates a modified example by extracting a part of the light source device of FIG. 18C. Since the other configurations are the same as those of the light source device of FIG. 18C, illustration and repeated description are omitted. As shown in FIG. 18D(2), the sub-reflector 310 may not be provided, but as in FIG. 18D(1), the height of the light-shielding plate 410 is adjusted to be lower in the Z-axis direction with respect to the position of the phosphor 114 so that the main light ray of the fluorescence output laterally from the phosphor 114 enters the effective region of the polarization conversion element 21 without being blocked by the light-shielding body 410.

[0136] Regarding the light source devices of FIGS. 18A, 18B, 18C, and 18D, as shown in FIG. 18A(1), a side wall 400 may be provided to prevent dust from entering the space between the reflection surface of the reflection type light guide 306 and the liquid crystal display panel 11, to prevent stray light from being generated outside the light source device, and to prevent stray light from entering from outside the light source device. When the side wall 400 is provided, it is arranged so as to sandwich the space between the light guide 306 and the diffusion plate 206.

[0137] The light emission surface of the polarization conversion element 21 that emits the light polarization-converted by the polarization conversion element 21 faces the space surrounded by the side wall 400, the light guide 306, the diffusion plate 206, and the polarization conversion element 21. Further, among the inner surfaces of the side wall 400, the surface of the portion that covers the space (the space on the right side from the light emission surface of the polarization conversion element 21 in FIG. 18B(1)) where light is output from the light emission surface of the polarization conversion element 21 from the side uses a reflection surface having a reflection film or the like. That is, the surface of the side wall 400 facing the above space includes a reflection region having a reflection film. By using the surface of the side wall 400 as the reflection surface, the light reflected by the reflection surface can be reused as the light source light, and the luminance of the light source device can be improved.

[0138] Of the inner surfaces of the side wall 400, the surface portion that covers the polarization conversion element 21 from the side is a surface with a low light reflectance (such as a black surface without a reflective film). This is because when reflected light is generated on the side surface of the polarization conversion element 21, light in an unexpected polarization state is generated, which causes stray light. In other words, by making the above surface a surface with a low light reflectance, the generation of stray light in the image and light in an unexpected polarization state can be prevented or suppressed. Further, a hole through which air passes may be formed in a part of the side wall 400 so as to improve the cooling effect.

[0139] Note that the light source devices in FIGS. 18A, 18B, 18C, and 18D have been described on the premise of a configuration using the polarization conversion element 21. However, the polarization conversion element 21 may be omitted from these light source devices. In this case, the light source device can be provided at a lower cost.

[0140] <Another Example 3 of the Light Source Device> Subsequently, the optical system configuration of a light source device using the reflective light guide 304 based on the light source device shown in Example 1 of the light source device will be described in detail with reference to FIGS. 19A(1), (2), (3), and 19B.

[0141] FIG. 19A shows a state in which the LEDs 14 constituting the light source are provided on the substrate 102. These are configured as a unit 328 having a plurality of blocks with the collimator 18 and the LED 14 as a pair of blocks. Since the collimator 18 of the present embodiment is close to the LED 14, a glass material is adopted in consideration of heat resistance. The shape of the collimator 18 is the same as the shape described for the collimator 15 in FIG. 18. Further, by providing a light shielding plate 317 in the previous stage before the light enters the polarization conversion element 21, unnecessary light is prevented or suppressed from entering the subsequent optical system, and the temperature rise due to the unnecessary light is reduced.

[0142] Regarding other configurations and effects of the light source shown in FIG. 19A, since they are the same as those in FIGS. 18A, 18B, 18C, and 18D, repeated explanations are omitted. Similar to the light source devices in FIGS. 18A, 18B, and 18C, the light source device in FIG. 19A may be provided with sidewalls. Regarding the configuration and effects of the sidewalls, since they have already been described, repeated explanations are omitted.

[0143] FIG. 19B is a cross-sectional view of FIG. 19A(2). Regarding the configuration of the light source shown in FIG. 19B, it is common to a part of the structure of the light source in FIG. 18 and has already been described in FIG. 18, so repeated explanations are omitted.

[0144] <Another Example 4 of the Light Source Device> Subsequently, the light source device in FIG. 23 is composed of a unit 328 having a plurality of blocks with a collimator 18 and an LED 14 as a pair of blocks used in the light source device shown in FIG. 19. Regarding the optical system configuration of the light source device using LEDs arranged at both ends of the back surface of the liquid crystal display panel 11 and a reflective light guide 504, it will be described in detail with reference to FIGS. 23(a), (b), and (c).

[0145] FIG. 23 shows a state in which the LEDs 14 constituting the light source are provided on a substrate 505, and these are composed of a unit 503 having a plurality of blocks with a collimator 18 and an LED 14 as a pair of blocks. The unit 503 is arranged at both ends of the back surface of the liquid crystal display panel 11 (in this embodiment, three units are arranged side by side in the short side direction). The light output from the unit 503 is reflected by the reflective light guide 504 and is configured to be incident on the oppositely arranged liquid crystal display panel 11 (shown in FIG. 23(c)).

[0146] As shown in FIG. 23(c), the reflective light guide 504 is divided into two blocks corresponding to the units arranged at its respective ends and is arranged such that the central part is the highest. Since the collimator 18 is close to the LED 14, a glass material is adopted in consideration of the heat resistance to the heat emitted from the LED 14. The shape of the collimator 18 is the same as the shape described for the collimator 15 in FIG. 18.

[0147] The light from LED 14 enters the polarization conversion element 501 through the collimator 18. The configuration is such that the distribution of the light incident on the subsequent reflective light guide 504 is adjusted according to the shape of the optical element 81. That is, the light quantity distribution of the light beam incident on the liquid crystal display panel 11 is optimally designed by adjusting the shape of the collimator 18 described above, the arrangement and shape of the optical element 81, the diffusion characteristics and the shape of the reflecting surface (cross-sectional shape) of the reflective light guide, the inclination of the reflecting surface, and the surface roughness of the reflecting surface.

[0148] As the shape of the reflecting surface provided on the surface of the reflective light guide 504, as shown in FIG. 23(b), a plurality of reflecting surfaces are arranged facing the light emitting surface of the polarization conversion element, and the inclination, area, height, and pitch of the reflecting surface are optimized according to the distance from the polarization conversion element 21. Further, by dividing the region that becomes the same reflecting surface (that is, the surface facing the polarization conversion element) into polyhedrons, the light quantity distribution of the light beam incident on the liquid crystal display panel 11 can be set to a desired value (optimized) as described above.

[0149] Similar to the reflective light guide described with reference to FIG. 18B, the reflecting surface provided on the reflective light guide is configured such that one surface (the region where light is reflected) has a shape with a plurality of inclinations (in the example of FIG. 23, it is divided into 14 parts in the XY plane and composed of different inclined surfaces), so that the reflected light can be adjusted with higher precision. Further, in order to prevent the reflected light from the reflective light guide from leaking from the side surface of the light source device 13, a light shielding wall 507 is provided to prevent the generation of leakage light in directions other than the desired direction (the direction toward the liquid crystal display panel 11).

[0150] Also, the unit 503 arranged on the left and right of the reflective light guide 504 in FIG. 23 may be replaced with the light source device in FIG. 18. That is, a plurality of light source devices in FIG. 18 (substrate 102, reflector 300, LED 14, etc.) may be prepared, and such a plurality of light source devices may be arranged at positions facing each other as referred to in FIGS. 23(a), (b), and (c).

[0151] Figure 24(B) shows a light source device configured by arranging six units 503 shown in Figure 24(A) at the upper part and six units at the lower part. As shown in the figure, the LEDs are configured in a unit structure with five arranged horizontally and are current-controlled by a single power source to obtain a desired luminance. Therefore, as a light source device for illuminating a liquid crystal panel, the light source luminance can be controlled for each region irradiated by each unit. In the configuration of Figure 24, there are a reflecting surface 502 different from the reflecting surface 222 and the reflecting surface 222. The reflecting surface 222 has a shape like a horizontal grid or a strip shape with a predetermined width. The reflecting surface 502 has a shape like a vertical and horizontal grid. From these shapes, the luminance and angle of the reflected light can be finely controlled. Therefore, even when a single light source is used in the flat panel display and the spatial floating video information device shown in Figures 14 and 15, the light source luminance can be controlled for each irradiation region.

[0152] Figure 20 is a cross-sectional view showing an example of the shape of the diffusion plate 206. As described above, the divergent light output from the LED is converted into substantially parallel light by the reflector 300 or the collimator 18, converted into a specific polarization wave by the polarization conversion element 21, and then reflected by the light guide. Then, the light beam reflected by the light guide passes through the flat portion of the incident surface of the diffusion plate 206 and enters the liquid crystal display panel 11 (see the two solid arrows indicating "reflected light from the light guide" in Figure 19).

[0153] Also, among the light emitted from the polarization conversion element 21, the divergent light beam is totally reflected by the inclined surface of the protrusion having an inclined surface provided on the incident surface of the diffusion plate 206 and enters the liquid crystal display panel 11. In order to totally reflect the light emitted from the polarization conversion element 21 by the inclined surface of the protrusion of the diffusion plate 206, the angle of the inclined surface of the protrusion is changed based on the distance from the polarization conversion element 21. When the angle of the inclined surface of the protrusion on the side far from the polarization conversion element 21 or the side far from the LED is α and the angle of the inclined surface of the protrusion on the side close to the polarization conversion element 21 or the side close to the LED is α', α is smaller than α' (α < α'). By setting it like this, it becomes possible to effectively use the polarization-converted light beam.

[0154] <Diffusion Characteristic Control Technology of Video Display Device> As a method for adjusting the diffusion distribution of the video light from the liquid crystal display panel 11, a lenticular lens may be provided between the light source device 13 and the liquid crystal display panel 11, or on the surface of the liquid crystal display panel 11, and the shape of the lens may be optimized. That is, by optimizing the shape of the lenticular lens, the emission characteristics of the video light (hereinafter also referred to as "video light beam") emitted from the liquid crystal display panel 11 in one direction can be adjusted.

[0155] Alternatively or additionally, a microlens array may be arranged in a matrix on the surface of the liquid crystal display panel 11 (or between the light source device 13 and the liquid crystal display panel 11), and the arrangement mode may be adjusted. That is, by adjusting the arrangement of the microlens array, the emission characteristics of the video light beam emitted from the video display device 1 in the X-axis and Y-axis directions can be adjusted, and as a result, a video display device having desired diffusion characteristics can be obtained.

[0156] As a further configuration example, two lenticular lenses may be arranged in combination at the position where the video light emitted from the video display device 1 passes, or a sheet for adjusting the diffusion characteristics by arranging a microlens array in a matrix may be provided. By adopting such an optical system configuration, in the X-axis and Y-axis directions, the luminance (relative luminance) of the video light can be adjusted according to the reflection angle of the video light (the reflection angle with respect to the case of reflecting in the vertical direction as a reference (0 degrees)).

[0157] In this embodiment, by using such a lenticular lens, as shown in the graphs (plot curves) of "Example 1 (Y direction)" and "Example 2 (Y direction)" in FIG. 27(b), excellent optical characteristics clearly different from the graph (plot curve) of the conventional characteristics can be obtained. Specifically, in the plot curves of Example 1 (Y direction) and Example 2 (Y direction), the luminance characteristics in the vertical direction are sharpened, and further, by changing the balance of the directivity characteristics in the up and down directions (positive and negative directions of the Y-axis), the luminance (relative luminance) of the light due to reflection and diffusion can be increased.

[0158] Therefore, according to this embodiment, image light from a surface-emitting laser image source, which has a narrow diffusion angle (high straightness) and is image light with only a specific polarization component, can be adjusted so as to suppress ghost images generated by a retroreflective member when using a conventional image display device and efficiently deliver a spatial floating image due to retroreflection to the viewer's eyes.

[0159] Further, with the light source device described above, with respect to the light emission diffusion characteristics (denoted as "conventional characteristics" in the figure) from a general liquid crystal display panel shown in FIGS. 28(A) and (B), it is possible to provide significantly angled directivity characteristics in both the X-axis direction and the Y-axis direction. In this embodiment, by providing such narrow-angle directivity characteristics, it is possible to realize an image display device that emits light of a specific polarization, emitting an image light beam that is nearly parallel in a specific direction.

[0160] FIG. 27 shows an example of the characteristics of the lenticular lens employed in this embodiment. In this example, in particular, the characteristics in the X direction (vertical direction) with respect to the Z axis are shown. For characteristic O, the peak in the light emission direction is at an angle of around 30 degrees upward from the vertical direction (0 degrees), showing a luminance characteristic that is symmetric about the vertical. Also, the plot curves of characteristics A and B shown in the graph of FIG. 27 are examples of characteristics in which the image light above the peak luminance is condensed at around 30 degrees to increase the luminance (relative luminance). Therefore, in these characteristics A and B, as can be seen by comparison with the plot curve of characteristic O, in the region where the inclination (angle θ) from the Z axis to the X direction exceeds 30 degrees (θ > 30°), the luminance (relative luminance) of the light rapidly decreases.

[0161] That is, according to the optical system including the above-described lenticular lens, when the image light beam from the image display device 1 is incident on the retroreflective member, the emission angle and the viewing angle of the image light aligned at the included angle by the light source device 13 can be adjusted, and the degree of freedom in installing the retroreflective sheet can be greatly improved. As a result, the degree of freedom in the relationship of the imaging position of the spatial floating image that is reflected or transmitted through the windshield and imaged at a desired position can be greatly improved. As a result, it is possible to efficiently reach the eyes of outdoor or indoor viewers as light with a narrow diffusion angle (high straight-ahead property) and only a specific polarization component. According to this, even if the intensity (luminance) of the image light from the image display device 1 is reduced, the viewer can accurately recognize the image light and obtain information. In other words, by reducing the output of the image display device 1, it is possible to realize an information display system with low power consumption.

[0162] As described above, various embodiments or examples (i.e., specific examples) to which the present invention is applied have been described in detail. On the other hand, the present invention is not limited to only the above-described embodiments (specific examples), and includes various modifications. For example, the above-described embodiments have described the entire system in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. Also, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Also, for a part of the configuration of each embodiment, addition, deletion, or replacement with other configurations is possible.

[0163] The light source device described above is not limited to the spatial floating image display device, and can also be applied to information display devices such as HUD, tablet, digital signage, etc.

[0164] In the technology according to this embodiment, by displaying high-resolution and high-brightness video information in a state of spatial floating, for example, it is possible for a user to operate without feeling anxiety about the contact infection of infectious diseases. If the technology according to this example is used in a system used by an unspecified number of users, it is possible to reduce the risk of contact infection of infectious diseases and provide a non-contact user interface that can be used without feeling anxiety. According to the present invention that provides such a technology, it contributes to "3 Ensure healthy lives and promote well-being for all" among the Sustainable Development Goals (SDGs) proposed by the United Nations.

[0165] Also, in the technology according to the above-described embodiment, by reducing the divergence angle of the emitted video light and further aligning it to a specific polarization, only regular reflected light can be efficiently reflected to the retroreflective member, so the light utilization efficiency is high, and it is possible to obtain a bright and clear spatial floating video. According to the technology according to this embodiment, it is possible to provide a non-contact user interface with excellent usability that can significantly reduce power consumption. According to the present invention that provides such a technology, it contributes to "9 Build the infrastructure for industry and innovation" and "11 Make cities and human settlements inclusive, safe, resilient and sustainable" among the Sustainable Development Goals (SDGs) proposed by the United Nations.

[0166] Furthermore, in the technology according to the above-described embodiment, it is possible to form a spatial floating video with highly directional (straight-forward) video light. In the technology according to this example, even when displaying videos that require high security in bank ATMs, ticket vending machines at stations, etc., or videos with high confidentiality that need to be concealed from people facing the user directly, by displaying highly directional video light, it is possible to provide a non-contact user interface with less risk of the spatial floating video being spied on by people other than the user. By providing the above-described technology, the present invention contributes to "11 Make cities and human settlements inclusive, safe, resilient and sustainable" among the Sustainable Development Goals (SDGs) proposed by the United Nations.

Description of Reference Numerals

[0167] 1… Image display device, 2… First retroreflective member, 5… Second retroreflective member, 3… Spatial image (spatial floating image), 100… Transparent plate, 13… Light source device, 54… Light direction conversion panel, 105… Linear Fresnel sheet, 101… Absorptive polarizing sheet (absorptive polarizing plate), 200… Flat panel display, 201… Housing, 203… Sensing system, 226… Sensing area, 102… Substrate, 11, 335… Liquid crystal display panel, 206… Diffusion plate, 21… Polarization conversion element, 300… Reflector, 213… λ / 2 plate, Reflective light guide… 306, Reflective surface… 307, 308, 310… Sub-reflector, 204… Spatial floating video, 334… Video light control sheet, 336… Transmission part, 337… Light absorption part, 81… Optical element, Polarization conversion element… 501, Unit… 503, Light shielding wall… 507, 401, 402… Light shielding plate, 320… Base material

Claims

1. A spatial floating image display device, a first display panel for displaying an image, a light source device for the first display panel, a retroreflective member that reflects image light from the first display panel and displays a real image spatial floating image in the air with the reflected light, a second display panel for displaying an image on a surface, and comprises a first sensor for sensing a spatial region corresponding to the spatial floating image, comprises a second sensor for sensing an image corresponding to the image displayed on the second display panel, wherein the sensing region of the first sensor and the sensing region of the second sensor exist on the same plane, a spatial floating image display device.

2. In the spatial floating image display device according to Claim 1, the first sensor is a TOF (Time of Flight) type sensor including a light source and a light receiving unit, a spatial floating image display device.

3. In the spatial floating image display device according to Claim 1, the second sensor is a TOF (Time of Flight) type sensor including a light source and a light receiving unit, a spatial floating image display device.

4. In the spatial floating image display device according to Claim 2, the wavelength of the light source light of the first sensor is a wavelength of 900 (nm) or more, a spatial floating image display device.

5. In the spatial floating image display device according to Claim 3, the wavelength of the light source light of the second sensor is a wavelength of 900 (nm) or more, a spatial floating image display device.

6. In the spatial floating image display device according to any one of Claims 1 to 5, the light source device comprises a dot-shaped or planar light source, a reflector for reflecting light from the light source, and a light guide for guiding light from the reflector toward the first display panel, wherein the reflecting surface of the reflector has a shape asymmetric with respect to the optical axis of the emitted light of the light source, a spatial floating image display device.

7. In the spatial floating image display device according to Claim 6, the light guide is a reflective light guide, a spatial floating image display device.

8. In the spatial floating image display device according to Claim 6 or Claim 7, a diffusion plate for diffusing light from the light guide, and side walls arranged so as to sandwich the space between the light guide and the diffusion plate, a spatial floating image display device.

9. In the spatial floating image display device according to any one of Claims 6 to 8, The reflector uses a plastic material, a glass material, or a metal material. Spatial floating image display device. **Claim 10**: In the spatial floating image display device according to Claim 1, it is provided with an image light control sheet disposed close to the image display surface of the first display panel, the image light beam whose light emission direction is controlled by the image light control sheet forms a spatial floating image after being reflected by the retroreflective member. The retroreflective member is disposed at an inclination of 35 degrees or more such that the end surface on the image viewer side of the retroreflective member is lower than the other end surface. Spatial floating image display device. **Claim 11** In the spatial floating image display device according to Claim 10, the spatial floating image display device is such that an image viewer looks down and monitors the spatial floating image, the first display panel and the retroreflective member are arranged in order from a position far from the image viewer, the image light from the first display panel is controlled by the image light control sheet disposed close to the image display surface of the first display panel, the retroreflective member reflects the light passing through the image light control sheet, and a real image spatial floating image is displayed in the air by the reflected light. Spatial floating image display device. **Claim 12**: In the spatial floating image display device according to Claim 1, the retroreflective member is disposed at an inclination such that the lower part is pulled forward with respect to the upper part of the spatial floating image display device, and the image light is disposed so as to be incident on the retroreflective member at an inclination. Spatial floating image display device.

Images