WO2023199685A1 - Spatial floating video display system and spatial floating video processing system - Google Patents

Abstract

The purpose of the present invention is to provide, with respect to a spatial floating video display system or a spatial floating video display device, a feature by which a suitable video can be displayed with high visibility (visual resolution and contrast).　The spatial floating video display system of the present invention comprises: a display panel (11) that displays a video; a light source device (13) for the display panel; and a retroreflective member (5) that reflects video light from the display panel (11) and displays a spatial floating video of a real image in the air by using the reflected light. The retroreflective member (5) comprises a first reflecting portion and a second reflecting portion, and an angle formed between a spatial floating video (3) floating in the center and a spatial floating video (3C, 3d) formed at a specific angle and separated by a specific distance on the basis of the spatial floating video floating in the center is adjusted by an intersection angle between the first reflecting portion and the second reflecting portion.

Description

Space floating video display system and space floating video processing system

The present invention relates to a space floating video display system and a space floating video processing system.

As spatial floating image display systems, image display devices that display images directly to the outside and display methods that display images as a spatial screen are already known. Further, a detection system that reduces false detections caused by operations on the operation surface of the displayed spatial image is also disclosed in Patent Document 1, for example.

JP2019-128722A

As spatial floating image display systems, image display devices that display images directly to the outside and display methods that display images as a spatial screen are already known. However, in the above-mentioned prior art floating image display system, no consideration is given to optimization techniques for the design including the light source of the image display device that is the image source of the floating image in order to display the floating image.

An object of the present invention is to provide a technology capable of displaying a suitable image with high visibility (visual resolution and contrast) in a space floating image display system or a space floating image display device.

In order to solve the above problem, for example, the configuration described in the claims is adopted. The present application includes a plurality of means for solving the above-mentioned problems, and a spatial floating video display device as an example thereof will be listed below. A space floating video display system as an example of the present application includes a display panel for displaying a video, a light source device for the display panel, a space floating video that reflects video light from the display panel, and creates a real space floating video in the air using the reflected light. The retroreflective member has a first reflecting part and a second reflecting part, and has a space floating image floating in the center and a specific angle based on the space floating image floating in the center. The angle formed by the space-floating image formed at a distance is adjusted by the intersection angle of the first reflecting section and the second reflecting section.

According to the present invention, a spatial floating image can be suitably displayed. Problems, configurations, and effects other than those described above will be made clear by the description of the embodiments below.

FIG. 2 is a diagram showing the configuration of a retroreflective member and the generation position of a spatially floating image according to an embodiment of the present invention. FIG. 3 is an explanatory diagram for explaining the mechanism of generation of ghost images due to extraordinary rays generated by retroreflection according to an embodiment of the present invention. FIG. 7 is an explanatory diagram for explaining the generation mechanism of abnormal rays generated in a retroreflective member used in another spatially floating image display system. FIG. 3 is an explanatory diagram for explaining a mechanism for erasing abnormal rays generated when external light is incident on a retroreflective member according to an embodiment of the present invention. FIG. 2 is a characteristic diagram showing optimal usage conditions of a retroreflective member in a floating image display system according to an embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram illustrating an example of a main part configuration and a retroreflection part configuration of a spatially floating video display system according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a second embodiment of the configuration of main parts and the configuration of a retroreflection part of a floating image display system in space according to an embodiment of the present invention. FIG. 3 is a diagram illustrating a third embodiment of the configuration of main parts and the configuration of a retroreflection part of a floating image display system according to an embodiment of the present invention. FIG. 4 is a diagram illustrating a fourth embodiment of the configuration of main parts and the configuration of a retroreflection part of a floating image display system in accordance with an embodiment of the present invention. FIG. 2 is an explanatory diagram for explaining the operating principle of an optical member that refracts image light used in the spatially floating image display system of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram showing the structure of a floating image display system using an optical member that refracts image light according to the present invention, and for explaining the principle thereof. FIG. 3 is an explanatory diagram for explaining the structure of an optical member that refracts image light used in the spatially floating image display system of the present invention. FIG. 2 is an explanatory diagram for explaining the arrangement of an optical member and a video source that prevents a viewer from directly viewing a displayed video of the video source used in the spatially floating video display system of the present invention. FIG. 2 is a cross-sectional view showing the arrangement of members that block extraordinary rays generated in a retroreflection section according to an embodiment of the present invention. 1 is a diagram showing the configuration of main parts of a first embodiment of a floating video display system according to an embodiment of the present invention; FIG. FIG. 2 is a diagram illustrating the appearance and main configuration of a second embodiment of a floating video display system according to an embodiment of the present invention. FIG. 6 is a diagram illustrating the external appearance and main configuration of a second embodiment of another spatially floating video display system according to an embodiment of the present invention. FIG. 2 is an explanatory diagram for explaining sensing means provided in the floating image display system according to the embodiment of the present invention. FIG. 7 is a diagram illustrating another example of a specific configuration of a light source device of another type. FIG. 7 is a structural diagram showing another example of a specific configuration of a light source device of another type. FIG. 7 is a diagram illustrating a part of another example of a specific configuration of a light source device of another type. FIG. 7 is a diagram illustrating a part of another example of a specific configuration of a light source device of another type. FIG. 7 is a diagram illustrating a part of another example of a specific configuration of a light source device of another type. FIG. 7 is a structural diagram showing another example of a specific configuration of a light source device of another type. FIG. 7 is a diagram illustrating another example of a specific configuration of a light source device of another type. It is an enlarged view which shows the surface shape of the light guide diffuser part of another example of the specific structure of a light source device. FIG. 2 is a cross-sectional view showing an example of a specific configuration of a light source device. FIG. 2 is a structural diagram showing an example of a specific configuration of a light source device. FIG. 3 is a perspective view, a top view, and a cross-sectional view showing an example of a specific configuration of a light source device. FIG. 2 is a perspective view and a top view showing an example of a specific configuration of a light source device. FIG. 3 is an explanatory diagram for explaining light source diffusion characteristics of a video display device. FIG. 3 is an explanatory diagram for explaining light source diffusion characteristics of a video display device. FIG. 3 is an explanatory diagram for explaining the diffusion characteristics of the video display device. FIG. 3 is an explanatory diagram for explaining the diffusion characteristics of the video display device. FIG. 3 is a diagram showing a coordinate system for measuring visual characteristics of a liquid crystal panel. FIG. 3 is a diagram showing brightness angle characteristics (longitudinal direction) of a general liquid crystal panel. FIG. 3 is a diagram showing the brightness angle characteristics (lateral direction) of a general liquid crystal panel. FIG. 3 is a diagram showing the contrast angle characteristics (longitudinal direction) of a general liquid crystal panel. FIG. 3 is a diagram showing the contrast angle characteristics (lateral direction) of a general liquid crystal panel. FIG. 3 is an explanatory diagram for explaining the mechanism of generation of a plurality of spatially floating images generated by retroreflection according to an embodiment of the present invention. FIG. 1 is an explanatory diagram for explaining the main configuration of a spatially floating image display system using a plurality of spatially floating images generated by retroreflection according to an embodiment of the present invention.

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 "this disclosure") described below. The present invention extends to the spirit of the invention and the scope of the technical ideas described in the claims, or to equivalents thereof. Further, the configuration of the embodiment (example) described below is merely an example, 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. be.

In addition, in the drawings for explaining the present invention, parts having the same or similar functions are given the same reference numerals, different names are used as appropriate, and repeated explanations of functions, etc. are omitted. There is. In the following description of the embodiment, an image floating in space is expressed using the term "space floating image." Instead of this terminology, expressions such as "aerial image", "aerial image", "aerial floating image", "aerial floating optical image of a display image", "aerial floating optical image of a display image", etc. may be used. The term "space floating image" mainly used in the description of the embodiments is used as a representative example of these terms.

The present disclosure, for example, transmits an image of 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 floats the image inside or outside of a store (space). The present invention relates to a display system that can display images. The present disclosure also relates to a large-scale digital signage system configured using a plurality of such display systems.

According to the following embodiments, it is possible to display high-resolution images floating in space, for example, on the glass surface of a show window or on a light-transmitting board. At this time, by making the divergence angle of the emitted image light small, that is, an acute angle, and aligning it with a specific polarization, it is possible to efficiently reflect only the regular reflected light to the retroreflection member. Therefore, the light utilization efficiency is high, and ghost images generated in addition to the main space floating image, which were a problem with conventional retroreflection methods, can be suppressed, and a clear space floating image can be obtained.

Further, by using a device including the light source of the present disclosure, it is possible to provide a novel and highly usable spatial floating video display system that can significantly reduce power consumption. Further, according to the technology of the present disclosure, it is possible to display a so-called unidirectional spatial floating image that is visible from outside the vehicle, for example, through the shield glass including the windshield, rear glass, and side glass of the vehicle. A floating video display system for a vehicle can be provided.

On the other hand, in conventional spatial floating image display systems, 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 image source. In the first retroreflective member 2 used in the conventional space-floating image display device, since the image light is diffused over a wide angle, the first retroreflective member 2, which is the first embodiment composed of polyhedrons shown in FIG. As shown in FIG. 3, in addition to the reflected light that is reflected on the surface, since the shape used for the retroreflective member 2a is a hexahedron, ghost images shown as 3a and 3f are included due to the image light incident obliquely. Six ghost images were generated, impairing the quality of the floating images. Additionally, the ghost images floating in the same space could be viewed by people other than the viewers, which posed a major problem from a security perspective.

Furthermore, in the second retroreflective member 5 used in the space floating image display device, as shown in FIG. 1(A), the first light control panel 221 and the second light control panel 222 each have a thickness. Optical members 20 having a large number of band-shaped planar light reflecting portions arranged at a constant pitch are arranged perpendicularly to one side surface of constant transparent flat plates 18 and 17. Here, the light reflecting parts of the optical members 20 constituting the first light control panel 221 and the second light control panel 222 are arranged to intersect with each other (orthogonally in this embodiment) in plan view. .

Next, the function of the second retroreflective member used in the space floating video display device and a specific example of the space floating video display device will be described. As shown in FIG. 1(B), the second retroreflective member 5 is generally arranged at an angle of 40 to 50 degrees with respect to the image display device 1. At this time, the spatially floating image 3 is emitted from the second retroreflective member 5 at the same angle as the angle at which the image light is incident on the second retroreflective member 5. At this time, the spatially floating image is formed at a symmetrical position separated by the same distance L1 between the image display device 1 and the second retroreflective member 5.

Hereinafter, the mechanism of forming a spatially floating image will be explained in detail using 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 reflecting section C (reflecting surface of the light reflecting member 20) of the second light control panel 222. , Next, the space floating image 3 (real image) is reflected by the planar light reflecting portion C' (reflecting surface of the light reflecting member 20) of the first light control panel 221, and the space floating image 3 (real image) is reflected at the outer position of the second retroreflective member 5. (the space on the other side). That is, by using this second retroreflective member 5, a spatially floating video device is established, and the image of the video display device 1 can be displayed in space as a spatially floating image.

In the second retroreflective member 5 described above, since there are two reflective surfaces as described above, in addition to the spatial floating image 3, as shown in FIGS. Two ghost images 3a and 3b are generated.

Furthermore, if the intensity of external light is high and it enters from the top surface of the second retroreflective member 5, the interval between the reflective surfaces (300 μm or less) will shorten, causing optical interference, and rainbow-colored reflected light will be observed, which will be visible to the viewer. It has been found that there is a problem in that the presence of the retroreflective member is recognized. Therefore, in order to prevent the interference light generated by the pitch of the reflective surface of the retroreflective member 5 due to the incidence of external light from returning to the viewer, the area where the interference light is generated is determined by using the incident angle of external light as a parameter in the measurement environment shown in Fig. 4. Obtained experimentally. The obtained results are shown in FIG. It has been found that when the pitch of the reflective surfaces is 300 μm and the height of the reflective surfaces is 300 μm, if the inclination angle θYZ of the retroreflective member is 35 degrees or more, the interference light does not return to the viewer side.

On the other hand, at the ratio (H/P) between the pitch P of the light reflecting member 20 and the height H of the reflecting surface, about 60% of the reflecting surface forms a spatially floating image due to retroreflection, and the remaining 40% forms a ghost image. It was found that the abnormal reflected light caused . In order to improve the resolution of floating images in the future, it will be essential to shorten the pitch of the reflective surfaces. In addition, in order to suppress the generation of ghost images, it is necessary to make the height of the reflecting surface higher than the current height, but due to manufacturing constraints of the second retroreflective member 5, the ratio of the pitch P and height H of the reflecting surface (H/P) should be selected in the range of 0.8 to 1.2 compared to the current 1.0.

As a result of the above-mentioned studies, the inventors have found that a retroreflective device that realizes high quality images of spatially floating images obtained in a spatially floating image display system using a second retroreflective member that generates fewer ghost images in principle. After studying the optical system, we arrived at the present invention. Hereinafter, the present invention will be explained in detail using the drawings.

<Example of configuration of first retroreflective optical system forming spatial floating image display system>
FIG. 6 is a diagram illustrating an example of the form of a reflexive optical system used to realize the spatially floating image display system of the present disclosure.

Furthermore, FIG. 6 is a diagram illustrating the overall configuration of the spatial floating video display system in this embodiment. Referring to FIG. 6, for example, according to the spatial floating display system of the present disclosure (hereinafter also referred to as "this system"), when the spatial floating video display system is placed on a desk for the viewer of the spatial floating video. In this case, the floating image will be viewed at an angle of θ6. At this time, the image formation position (angle) of the spatially floating image is the sum of the angle θ2 between the display surface of the video display device 1 and the retroreflective member 5, and the angle θ1 between the retroreflective member 5 and the spatially floating image ( We have found that arranging so that θ2 + θ1) is approximately equal is the optimal arrangement for viewing spatially floating images.

As described above, since the spatially 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 each arrangement are equal. Therefore, once the angle θ6 at which the viewer looks into the spatially floating image display system is determined, it is preferable to arrange the image display device 1 and the second retroreflective member 5 at an angle of θ2 = θ6/2 in the retroreflective optical system. . Furthermore, a predetermined distance L1 is required between the video display device 1 and the second retroreflective member 5 in order to improve the cooling efficiency of the video display device 1. Furthermore, in order to structurally obtain the above-mentioned angle θ2, it is necessary to determine the distance L2 with respect to L1.

The configuration of the spatial floating video display system of the present disclosure will be explained in more detail. As shown in FIG. 6, it includes an image display device 1 that diverges image light of a specific polarization into a narrow angle, and a second retroreflective member 5. The video display device 1 includes a liquid crystal display panel (hereinafter sometimes simply referred to as a liquid crystal panel) 11 and a light source device 13 that generates light of a specific polarization having narrow-angle diffusion characteristics.

Image light of a specific polarization from the image display device 1 is transmitted to the device (not shown) of the second retroreflection member 5. An absorption type polarizing sheet 101 having an anti-reflection film provided on the surface is provided on the surface in contact with the outside of the device (not shown). The reflected light reflected on the surface of the second retroreflective member 5 is generated by selectively transmitting the image light of a specific polarization and absorbing the other polarization included in the external light. Prevent effects.

Here, since the absorption type polarizing sheet 101 that selectively transmits image light of a specific polarization has a property of transmitting image light of a specific polarization, the image light of a specific polarization passes through the absorption type polarization sheet 101. To Penetrate. A spatially floating image 3 is formed at a symmetrical position with respect to the retroreflective member 5 by the transmitted image light.

Note that the light forming the floating image 3 is a collection of light rays that converge 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. do. Therefore, the floating image 3 is a highly directional image, unlike the diffused image light formed on a screen by a general projector or the like.

Therefore, in the configuration shown in FIG. 6, when the user views the floating image 3 from the direction shown in the figure, the floating image 3 is viewed as a bright image, but when viewed by another person from the vertical direction and front/back direction of the page, the floating image 3 is viewed as a bright image. , the floating image 3 cannot be viewed as an image at all. This characteristic is very suitable for use in a system that displays images that require high security or highly confidential images that should be kept secret from the person directly facing the user.

Note that depending on the performance of the retroreflection member 5, the polarization axes of the reflected image light may become uneven. In this case, some of the image light whose polarization axes are not aligned is absorbed by the above-mentioned absorptive polarizing sheet 101. Therefore, unnecessary reflected light is not generated in the retroreflective optical system, and deterioration in the image quality of the spatially floating image can be prevented or suppressed.

Furthermore, in the spatially floating image display device using the retroreflective optical system of the present disclosure, even when the viewer looks into the spatially floating image, the display screen of the image display device 1 is shielded from light by the reflective surface of the retroreflective member 5. be done. Therefore, in this space-floating video display device, the displayed image of the video display device 1 is more difficult to view directly than when the video display device 1 and the retroreflective member face each other directly.

<Example of configuration of second retroreflective optical system forming spatial floating image display system>
FIG. 7 is a diagram showing the main part configuration of another example of a retroreflective optical system for realizing a floating image display system according to an embodiment of the present invention. This spatial floating image display system is suitable for viewers to observe spatial floating images from diagonally above. 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 narrow-angle diffusion characteristics. The liquid crystal display panel 11 is comprised of a small liquid crystal display panel with a screen size of about 5 inches to a large liquid crystal display panel with a screen size of over 80 inches. Image light from the liquid crystal display panel 11 is emitted toward a retroreflective member (retroreflector or retroreflector plate) 5 .

Light from a light source device 13 with a narrow divergence angle, which will be described later, is incident on the liquid crystal panel 11 to generate an image light beam with a narrow divergence angle, which is incident on the retroreflective member 5 to obtain a spatial floating image 3. The spatially floating image 3 is formed at a symmetrical position of the image display device 1 with the retroreflective member 5 as a plane of symmetry. In order to eliminate the ghost image that occurs at this time and obtain a high quality floating image 3, an image light control sheet 334 whose structure is shown in FIG. 12(A) is provided on the output side of the liquid crystal panel 11 to prevent diffusion in unnecessary directions. It is better to control the characteristics.

Furthermore, it is better to use S-polarized waves because the image light from the liquid crystal panel 11 can theoretically increase the reflectance on reflective members such as retroreflective members, but if the viewer wears polarized sunglasses, Since the image is reflected or absorbed by polarized sunglasses, as a countermeasure to this problem, a depolarization element 339 is provided that optically converts a part of the image light of a specific polarization into the other polarization and converts it into pseudo natural light. This allows viewers to see a good spatial floating image even if they are wearing polarized sunglasses. When these are optically bonded using the adhesive 338, no light reflecting surface is generated and the quality of the spatial floating image is not impaired.

Commercially available depolarization elements include Cosmoshine SRF (manufactured by Toyobo Co., Ltd.) and depolarization adhesive (manufactured by Nagase Sangyo Co., Ltd.). In the case of Cosmoshine SRF (manufactured by Toyobo Co., Ltd.), by laminating an adhesive onto the image display device, reflection at the interface can be reduced and brightness can be improved.

In the case of a depolarizing adhesive, it is used by bonding a colorless transparent plate and an image display device via the depolarizing adhesive. An image light control sheet 338 is also provided on the image exit surface of the retroreflective member 5 to eliminate ghost images generated on both sides of the regular image of the space floating image 3 by unnecessary light. In this embodiment, the retroreflective member 5 is arranged parallel to a horizontal plane in space, and the interspace floating image 3 can be displayed at an angle of θ1 with respect to the horizontal plane. For this purpose, the display surface of the image display device 1 is tilted by θ1 to the side opposite to the space floating image 3 with respect to the horizontal plane. Further, in this embodiment, the video display device 1 includes a light source device 13 that generates light of a specific polarization having a diffusion characteristic that is narrow to the liquid crystal display panel 11.

<Example of configuration of third retroreflective optical system forming spatial floating image display system>
FIG. 8 is a diagram illustrating the configuration of another example showing the configuration of the main parts of a reflexive optical system for realizing a spatially floating image display system. This spatial floating image display system is suitable for viewers to observe the spatial floating image from diagonally above the front. 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 narrow-angle diffusion characteristics. The liquid crystal display panel 11 is comprised of a small liquid crystal display panel with a screen size of about 5 inches to a large liquid crystal display panel with a screen size of over 80 inches.

Image light from the liquid crystal display panel 11 is emitted toward the retroreflective member 5. Light from a light source device 13 with a narrow divergence angle, which will be described later, is incident on the liquid crystal panel 11 to generate an image light beam with a narrow divergence angle, which is incident on the retroreflective member 5 to obtain a spatial floating image 3. The spatially floating image 3 is formed at a symmetrical position of the image display device 1 with the retroreflective member 5 as a plane of symmetry.

In order to eliminate ghost images generated in the spatial floating image 3 and obtain a high-quality spatial floating image 3, an image light control sheet 334 is provided on the output side of the liquid crystal panel 11 shown in FIG. 14(A) to control unnecessary directions. It is also possible to control the diffusion characteristics of On the other hand, as shown in FIG. 14(B), by providing an image light control sheet 338 on the image exit surface of the retroreflective member 5, ghost images generated on both sides of the regular image of the spatially floating image 3 due to unnecessary light can be erased. It's okay. By tilting (θ2) the retroreflective sheet 5 with respect to the horizontal plane, the spatial floating image 3 can be generated at an angle of θ1 with respect to the horizontal plane. For this reason, for example, when the configuration shown in FIG. 8 is incorporated into the upper part of a KIOSK terminal to display a floating image in space as an avatar at the upper end of the terminal, the image light is directed toward the viewer's eyes, so high brightness is required. You can view images floating in space.

In order to obtain the spatially floating image 3 at a desired elevation angle and position, as in the first and second embodiments, the inclination angle θ2 of the retroreflective member 5, the inclination angle θ3 of the image display device 1, and their respective positions are optimally designed. Just do it.

<Example of configuration of the fourth retroreflective system forming a spatially floating video display system>
FIG. 9 is a diagram showing the main part configuration of another example of a retroreflective optical system for realizing a spatially floating image display system. This spatial floating image display system is suitable for a viewer to observe a spatial floating image from diagonally above. 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 narrow-angle diffusion characteristics. The liquid crystal display panel 11 is comprised of a small liquid crystal display panel with a screen size of about 5 inches to a large liquid crystal display panel with a screen size of over 80 inches.

In order to cause the image light from the liquid crystal display panel 11 to obliquely enter the retroreflective member 5 disposed at a position facing directly, a linear Fresnel sheet 105 as shown in FIG. 10 is used as the image light control sheet 334 in the image display device 1. It is preferable to arrange it close to the image display surface of the liquid crystal panel 11 and refract the image light in a desired direction. At this time, generation of unnecessary light can be suppressed by providing a light shielding layer on the vertical surface of the linear Fresnel to block the incidence of image light from sources other than the Fresnel lens. Furthermore, by providing an anti-reflection film on the image light incident surface and output surface of the linear Fresnel sheet, it is possible to suppress the generation of unnecessary light and obtain good characteristics.

The image light control sheet 334 equipped with the above-mentioned linear Fresnel sheet 105 emits the light toward the retroreflective member 5. Light from a light source device 13 with a narrow divergence angle, which will be described later, is incident on the liquid crystal panel 11 to generate an image light beam with a narrow divergence angle, which is incident on the retroreflective member 5 to obtain a spatial floating image 3. The spatial floating image 3 is formed at a symmetrical position on the display surface of the video display device 1 with the retroreflective member 2 as the symmetrical surface. In this embodiment, since the retroreflective member 2 and the video display device 1 are disposed in positions directly facing each other, when a viewer looks into the retroreflective member 5 of the spatially floating video display device, the liquid crystal panel 11 The displayed image overlaps with the floating image, significantly reducing the quality of the floating image.

In order to prevent the above-mentioned image light from overlapping with the spatially floating image, an image light control sheet is provided on the image light output surface of the liquid crystal panel 11. For example, a viewing angle control film (VCF) manufactured by Shin-Etsu Polymer Co., Ltd. is suitable as this image light control sheet, and its structure consists of alternating transparent silicon and black silicon, and a synthetic resin on the light input/output surface. Since it has a sandwich structure, the same effects as the external light control film of this example can be expected. At this time, the viewing angle control film (VFC) has transparent silicon and black silicon stretched in a predetermined direction arranged alternately. By tilting the stretching direction of the transparent silicon and black silicon of the image light control sheet 334 (θ10 in the figure) with respect to the image light control sheet 334, it is preferable to arrange the film so as to reduce moiré that occurs at the pitch between the pixels and the external light control film.

In the fourth embodiment, the retroreflective member 5 is arranged parallel to the bottom surface of the casing. As a result, external light enters the retroreflective member 5 and enters the inside of the casing, resulting in a deterioration in the image quality of the generated spatially floating image 3. In order to eliminate the ghost image generated in the spatial floating image 3 and obtain a high-quality spatial floating image 3, as shown in FIGS. 14(A) and (B), as in the second and third embodiments, An image light control sheet 334 may be provided on the output side of the liquid crystal panel 11 to control the diffusion characteristics in unnecessary directions. On the other hand, by providing an image light control sheet 338 also on the image exit surface of the retroreflective member 5, ghost images generated on both sides of the regular image of the spatially floating image 3 due to unnecessary light may be erased. By arranging the above-described structure inside the casing, external light is prevented from entering the retroreflective member 5, thereby preventing the generation of ghost images.

If the Fresnel angle of the linear Fresnel sheet 105 shown in FIG. 10 is 20 degrees and the base material of the linear Fresnel sheet 105 is acrylic, the refractive index is 1.49, and the output angle θ9 of the linear Fresnel sheet is 30 degrees. Become. When the emitted light flux from the video display device 1 is emitted perpendicularly to the display surface, if the divergence angle of the light flux is ±20 degrees, the incident angle to the output surface is +40 degrees at maximum. As a result, the angle of the light beam emitted from the linear Fresnel sheet 105 becomes +70 degrees at the maximum, which is 1.75 times as large. On the other hand, when the divergence angle is -20 degrees, the angle of incidence on the exit surface is 10 degrees, and the diffusion angle can be increased by 1.5 times from 20 degrees to 30 degrees.

Furthermore, it is possible to reduce the intensity of ghost images 3a and 3b that occur in addition to the spatially floating images 3 as shown in FIGS. It has also been found that since the ghost images 3a and 3b become larger, the brightness of the ghost images 3a and 3b can be reduced. The configuration and effects of the optical system in which the linear Fresnel sheet 105 shown in FIG. 10 is arranged between the retroreflective member 5 and the image display device 1 for the purpose of expanding the diffusion angle and reducing ghost images have been described above.

Next, an example of a casing using an optical system using a linear Fresnel sheet 105 in a spatially floating image display device will be described with reference to FIG. As described above, the action of the linear Fresnel sheet 105 refracts the image light flux. At this time, the direction of emission of the luminous flux from the image display device 1 is controlled so that the principal ray (the ray with the highest brightness) of the luminous flux forms a desired angle θ9 with respect to the spatially floating image plane 3. At this time, as shown in FIG. 10, the angle θ8 after refraction is calculated from the incident angle to the linear Fresnel sheet 105, the Fresnel angle, and the refractive index of the base material of the linear Fresnel sheet 105, and the output after refraction at the air interface The angle θ9 can also be found uniquely.

As a result, the principal ray B1 of the image light vertically emitted from the liquid crystal display panel 11 constituting the image display device 1 is refracted in an oblique direction, enters the retroreflective member 5, and is reflected by two reflective surfaces. , a spatially floating image 3 is formed at a position symmetrical to the liquid crystal display panel 11. At this time, the image light beam has a narrow divergence angle due to the light source device 13 of the present invention (included in the image display device 1 shown in FIG. 11) having narrow-angle diffusion characteristics as shown in FIG. 30, but the Fresnel lens Due to the action of the sheet 105, the diffusion angle θ11 of one light beam B11 with respect to the chief ray B1 is greatly expanded. Further, the other light B12 is diffused at a diffusion angle θ12 that is approximately equal to the original diffusion angle.

Therefore, when observing the spatial floating image 3, the brightness is highest when the image is viewed from the principal ray direction. For this reason, in a floating image display system having an optical system equipped with the linear Fresnel sheet 105, in order to direct the floating image with maximum brightness in the viewing direction of the viewer, the housing is attached to the housing base 516, which serves as the base. A hinge 513 is provided as a mechanism for holding the housing 511 and rotating it relative to the housing base 516 (see angle θ13 in FIG. 11), and the housing 511 is connected to the support arm 512 and one end thereof is connected to the hinge 513. do. As a result, the casing 511 can be rotated and held with respect to the casing base 516, so that the viewer can view the spatial floating image 3 at maximum brightness.

Furthermore, by providing the above-mentioned mechanism, when the space floating video display system is not in use, the housing 511 can be stored in the space provided by the housing cover 515 provided on the housing base 516 and the housing base 516. A compact storage format can be realized. Inside the housing 511, a video display device 1 including a liquid crystal panel (not shown) and a light source (not shown) and a retroreflective member 5 are built-in. Further, the back cover 514 has a structure in which an inclined surface is provided in a portion near the hinge to prevent the back cover 514 of the casing 511 from coming into contact with the casing base 516 during storage.

In contrast to the general form of a linear Fresnel sheet in which a Fresnel lens is formed in a direction parallel to one side of the outer shape, in the first embodiment of the present invention, as shown in FIG. 12(A), The Fresnel lens shape has at least one boundary surface. In FIG. 12(A), the boundary surface between the inclined linear Fresnel sheet 517 and the inclined linear Fresnel sheet 518 is shown. As a result, the image light flux from the image displayed on the flat display provided in the image display device 1 disposed on the lower side in FIG. 13 is refracted in the direction shown by the arrow in FIG. 12(A). As a result, it becomes possible to emit light in two directions for the obtained spatially floating image 3. Furthermore, it goes without saying that if the linear Fresnel sheet is configured such that there are two interfaces, it is possible to emit light from the floating image 3 in three directions.

Furthermore, as a second embodiment of the present invention, an eccentric Fresnel sheet 519 as shown in FIG. is emitted in a direction perpendicular to the Fresnel lens surface. As a result, the image light flux from the image displayed on the flat display provided in the image display device 1 disposed on the lower side in FIG. 13 is refracted in the direction shown by the arrow in FIG. 12(B). Here, in order to control the light emitted from the spatial floating image 3, optimal design is performed using the eccentricity of the circular Fresnel sheet and the Fresnel angle as parameters. Further, by making the Fresnel angles of the above-mentioned linear Fresnel sheet and circular Fresnel sheet constant, it is possible to simultaneously control the emitted light and reduce the thickness of the optical system set.

Above, we have described the technical means for controlling the exit direction of the image light flux from the image display device 1 through the action of the Fresnel lens. It goes without saying that the same effect can be obtained by controlling the direction and diffusion angle of light from the image. Further, as will be described later, the same effect can be obtained by controlling the emission direction of the light source beam that enters the liquid crystal panel 11 from the light source device 13.

<First configuration example of spatial floating video display system>
A first embodiment of a floating image display system using the four retroreflective optical systems described above is shown in FIG. The retroreflective member 5 is fixed to the transparent sheet 100 with adhesive or adhesive. By adopting a structure in which the distance between the image display device 1 and the retroreflective member 5 can be varied and the imaging position of the spatially floating image 3 can be varied, it is possible to give motion to the spatially floating image, creating a pseudo three-dimensional image. It is possible to realize a video display device that can display floating images in space.

<Second configuration example of spatial floating video display system>
A second embodiment of the spatial floating video display system will be described using FIG. 16. FIG. 16 shows a first embodiment in which a floating image display device 202 is incorporated into a tablet terminal. The floating image display device 202 and the flat display 200 are provided in the same housing 201.

Furthermore, the sensing unit 203 that covers all of the display image 204 of the flat display 200 and the spatially floating display 202 is placed on the same plane as the floating image 204 in a case in which both the flat display 200 and the spatially floating image display device 202 are located. It is provided at the end of the body 201. The sensing unit 203 can sense both the sensing area of the flat display 200 and the sensing area of the spatially floating display 202 on the same plane, shown as a sensing area 226 in FIG. 16 .

Note that when two or more sensing areas are provided, such as the sensing area of the flat display 200 and the sensing area of the spatially floating display 202, they may exist in parallel on a plane, or may exist above and below each other. It may exist either before or after. Moreover, they may exist on the same plane. In this case, the sensing unit 203 may be provided separately for each sensing area. The floating image display device 202 and the flat display 200 may be installed in the same housing 201.

Although the present embodiment is described using the flat display 200, it is not limited to a flat display, and any display may be used. In the second configuration example, this sensing area is located at a higher position toward the rear from the front of the device and has a slope. This allows for an easy-to-enter layout. The sensing unit will be described in detail later.

In this image display system, if the wavelength of the light source light of the TOF system, which is the ranging system of the sensing unit 203 used, is set to a long wavelength of 900 (nm) or more, it is less susceptible to the influence of external light. At this time, the user creates an illusion that the spatial operation input performed on the displayed spatial floating image 204 can also be performed on the image display surface of the flat display 200. Therefore, spatial operation input can be performed without directly touching the display screen of the flat display 200.

Furthermore, the inventors determined that the distance between the flat display 200 and the sensing area 226 should be such that even if the operator performs spatial operations based on the screen displayed on the flat display 200, the finger will not touch the surface of the flat display 200. was determined by experiment. As a result of this experiment, it was found that by separating the image formation position of the spatially floating image 204 from the flat display 200 by 40 mm or more, the probability that the operator directly touches the screen of the flat display 200 can be reduced to 50% or less. Furthermore, by setting the distance of 50 mm or more, the operation does not directly touch the flat display 200.

Note that the configuration described in FIG. 16 is not limited to the tablet terminal as described above, and may be incorporated into various display devices such as ATMs, automatic ticket vending machines, kiosk terminals, and stationary display devices.

<Third configuration example of spatial floating video display system>
A third embodiment of the spatial floating video display system will be described using FIG. 17. FIG. 17 shows a second embodiment in which a floating image display device 202 is incorporated into a tablet terminal.

The spatially floating image display device 202 and the flat display 200 are provided in the same housing 201, and a first sensing area (sensing region) 226a that covers the imaging area of the spatially floating image 204 of the spatially floating image display device 202 is sensed. There are a first sensing unit 203a and a second sensing unit 203b that senses a second sensing area 226b that covers the image display area of the flat display 200. The first sensing area 226a and the second sensing area 226b are provided at the starting points of the floating image display device 202 and the flat display 200, respectively.

Furthermore, the first sensing area 226a and the second sensing area 226b are arranged close to each other. The first sensing area and the second sensing area exist in parallel or in front of each other on a plane. As shown in FIG. 15, the first sensing area and the second sensing area may be arranged on the same plane. The floating image display device 202 and the flat display 200 may be installed in the same housing 201. Although the present embodiment is described using the flat display 200, the present invention is not limited to a flat display, and any display may be used. In this embodiment, they are arranged substantially parallel to the image display surface of the flat display 200. The sensing unit used here will also be described in detail later.

In the third embodiment of the image display system described above, the spatial operation input performed by the user on the displayed spatial floating image 204 can be similarly performed on the image display surface of the flat display 200. create an illusion. Therefore, spatial operation input can be performed without directly touching the display screen of the flat display 200.

Regarding this, as a result of evaluating the finger contact with the flat display 200 using a prototype using an actual device, it was found that by setting the imaging position of the spatially floating image 204 at least 50 mm away from the flat display 200, the operator can directly touch the flat display 200. It was possible to input spatial operations to the video display system without touching the screen of the display 200.

Note that, similarly to the above, the configuration described in FIG. 17 is not limited to tablet terminals, and may be incorporated into various display devices such as ATMs, automatic ticket vending machines, kiosk terminals, and stationary display devices.

<Technical means for sensing spatial images>
Sensing technology for pseudo-manipulating a space-floating image so that a viewer (operator) is bidirectionally connected to an information system via a space-floating image display device will be described below.

In a spatially floating image display system, image operations on the displayed image are made possible by reading sensing information together with the spatially floating image using a two-dimensional sensor, which will be described later.

Sensing technology for pseudo-manipulating a space-floating image will be described below, since the viewer (operator) is bidirectionally connected to the information system via the space-floating image display device. FIG. 18 is a principle diagram for explaining the sensing technology. A distance measuring device 203 having a built-in TOF (Time of Flight) system compatible with spatial floating images is provided. A near-infrared light emitting LED (Light Emitting Diode), which is a light source, is made to emit light in synchronization with the system signal.

An optical element for controlling the divergence angle is provided on the light emitting side of the LED, and a pair of highly sensitive avalanche diodes with picosecond time resolution are arranged as light receiving elements in the horizontal direction so as to correspond to the area. The LED that is the light source emits light in synchronization with the signal from the system, and the phase Δt is shifted by the time it takes for the light to reflect on the object to be measured (the tip of the viewer's finger) and return to the light receiving unit. . The distance to the object is calculated from this time difference Δt, and the position and movement of the operator's finger is sensed as two-dimensional information by combining it with position information from a plurality of sensors arranged in parallel.

Furthermore, it is possible to realize a spatial floating image display system or a spatial floating image display device that has a sensing function with fewer false detections for the display screen of a flat display and spatially floating images.

<Technical means to reduce ghost images>
Technical means for realizing a high-quality spatial video display device with reduced ghost images as a spatial floating video display device will be described with reference to FIG. In order to control the divergence angle of the image light from the liquid crystal panel 13 as an image display element in a desired direction, an image light control sheet 334 is provided on the output surface of the liquid crystal panel 13, as shown in FIG. 14(A). It is good to set up Further, an image light control sheet 334 is provided on the light exit surface, the light entrance surface, or both surfaces of the retroreflective member to absorb abnormal light that causes ghost images.

FIGS. 14(A) and 14(B) show a specific method of applying the image light control sheet 334 to a spatial image display device. An image light control sheet 334 is provided on the output surface of a liquid crystal panel 335, which is an image display element. At this time, in order to reduce moiré caused by interference due to the pitch between the pixels of the liquid crystal panel 13 and the transmitting section 336 and light absorbing section 337 of the image light control sheet 334, the following steps (1) and (2) must be taken. Two methods are effective.

(1) With respect to the vertical stripes caused by the transmitting part and the light absorbing part of the image light control sheet 334 and the pixel arrangement of the liquid crystal panel 335 (indicated by liquid crystal panel 11 in FIG. 15), as shown in FIG. Place it at an angle.

(2) The pixel size of the liquid crystal panel 335 is A (see double arrow A in FIG. 14(A)), and the pitch of the vertical stripes on the image light control sheet 334 is B (see double arrow B in FIG. 14(A)). (see), select this ratio (B/A) by excluding it from integral multiples.

One pixel 339 of the liquid crystal panel is made up of pixels of three colors RGB arranged in parallel, and is generally square, so it is not possible to suppress the above-mentioned moiré over the entire screen. Therefore, the slope θ10 shown in (1) should be optimized within the range of 5 degrees to 25 degrees so that the moire generation position can be intentionally shifted to a place where the spatial floating image is not displayed. was determined experimentally. Although we have described how to reduce moire using a liquid crystal panel, the moire that occurs between the retroreflective member 5 and the image light control sheet 334 is caused by the fact that both are striated structures, as shown in FIG. By optimally tilting the image light control sheet with attention to the X-axis, it is possible to reduce large moiré patterns with low frequencies that are visible even with long-wavelength visual inspection.

FIG. 14(A) is a vertical sectional view of the video display device 1 of the present invention in which the video light control sheet 334 is arranged on the video light exit surface of the liquid crystal panel 335. The image light control sheet 334 is configured by alternately arranging light transmitting portions 336 and light absorbing portions 337, and is adhesively fixed to the image light emitting surface of the liquid crystal panel 335 by an adhesive layer 338.

In addition, as described above, when a 7-inch WUXGA (1920 x 1200 pixels) liquid crystal display panel is used as the video display device 1, one pixel (one triplet) (as indicated by the double arrow A in FIG. 14(A)) Even if the length (length) is approximately 80 μm, it is sufficient if the pitch B, where the transmitting portion d2 of the image light control sheet 334 is 300 μm and the light absorbing portion d1 is 40 μm, is 340 μm. This configuration ensures sufficient transmission characteristics, controls the diffusion characteristics of the image light from the image display device that causes abnormal light, and eliminates ghost images that occur on both sides of the spatially floating image. can be reduced. Furthermore, in this case, if the thickness of the image control sheet is set to ⅔ or more of the pitch B, the ghost reduction effect will be greatly improved.

FIG. 14(B) is a vertical cross-sectional view of the retroreflective member of the present invention in which an image light control sheet 334 is arranged on the image light output surface of the retroreflective member 5. The image light control sheet 334 is constructed by alternately arranging light transmitting portions 336 and light absorbing portions 337, and is arranged to be inclined at 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-mentioned retroreflection can be absorbed, while the normal reflected light can be transmitted without loss.

When using a 7-inch WUXGA (1920 x 1200 pixels) liquid crystal display panel, even if one pixel (one triplet) (the length of double arrow A in Fig. 14(A)) is approximately 80 μm, for example, recursive If the pitch B is 420 μm, where the transmitting portion d2 of the reflecting portion is 400 μm and the light absorbing portion d1 is 20 μm, sufficient transmission characteristics and diffusion of image light from the image display device, which causes abnormal light in the retroreflective member, can be achieved. The characteristics are controlled to reduce ghost images that occur on both sides of the spatial floating image.

On the other hand, the above-mentioned image light control sheet 334 also prevents external light from entering the space floating image display device, leading to improved reliability of the component parts. For example, a viewing angle control film (VCF) manufactured by Shin-Etsu Polymer Co., Ltd. is suitable as this image light control sheet, and its structure is such that transparent silicon and black silicon are arranged alternately, and a synthetic resin is arranged on the light input/output surface. Since it has a sandwich structure, the same effects as the external light control film of this example can be expected.

<LCD panel performance>
Incidentally, in a typical TFT (Thin Film Transister) liquid crystal panel, the brightness and contrast performance differ depending on the mutual characteristics of the liquid crystal and the polarizing plate depending on the direction in which light is emitted. In the evaluation in the measurement environment shown in Figure 31, the characteristics of brightness and viewing angle in the transverse (up and down) direction of the panel were slightly different from the emission angle perpendicular to the panel surface (output angle 0 degrees), as shown in Figure 33. The characteristics at a different angle (+5 degrees in this example) are excellent. The reason for this is that in the transverse (vertical) direction of the liquid crystal panel, the characteristic of twisting light does not become 0 degrees when the applied voltage is maximum.

On the other hand, the contrast performance in the transverse (up and down) direction of the panel is excellent in the range of -15 degrees to +15 degrees, as shown in Figure 35, and when combined with the brightness characteristics, the contrast performance in the panel width direction (up and down) is excellent in the range of -15 degrees to +15 degrees. The best properties will be obtained if used within this range.

Furthermore, as shown in FIG. 32, the characteristics of brightness and viewing angle in the longitudinal (left and right) direction of the panel are excellent at the emission angle perpendicular to the panel surface (emission angle of 0 degrees). The reason for this is that in the longitudinal direction (left and right direction) of the liquid crystal panel, the characteristic of twisting light becomes 0 degrees when the applied voltage is maximum.

Similarly, the contrast performance in the longitudinal (left and right) direction of the panel is excellent in the range of -5 degrees to -10 degrees, as shown in Figure 34, and when combined with the brightness characteristics, the contrast performance in the longitudinal (left and right) direction of the panel is excellent in the range of -5 degrees to -10 degrees. The best properties will be obtained if used within this range. Therefore, the emission angle of the image light emitted from the liquid crystal panel is changed from the direction in which the best characteristics can be obtained by the light flux direction conversion means (reflection surfaces 307, 314, etc.) provided on the light guide of the light source device 13 described above. Making light incident on the panel and modulating the light with a video signal improves the image quality and performance of the video display device 1.

In order to make the most of the brightness and contrast characteristics of the liquid crystal panel as a video display element, it is necessary to set the incident light from the light source to the liquid crystal panel within the above-mentioned range to improve the image quality of the floating image. I can do it.

<How to control light source light>
In this embodiment, in order to improve the utilization efficiency of the luminous flux emitted from the light source device 13 and significantly reduce power consumption, the light source After being incident on the liquid crystal panel 11 at an incident angle that maximizes the characteristics of the liquid crystal panel 11, the device 13 emits an image beam whose brightness is modulated in accordance with the image signal toward the retroreflective member. At this time, in order to reduce the set volume of the spatially floating video display system, it is desired to increase the degree of freedom in the arrangement of the liquid crystal panel 11 and the retroreflective member. Furthermore, in order to form a floating image at a desired position after retroreflection and ensure optimal directivity, the following technical means are used.

A transparent sheet made of optical components such as a linear Fresnel lens shown in FIGS. 10 and 12 is provided as a light direction conversion panel on the image display surface of the liquid crystal panel 11, and a transparent sheet made of optical components such as a linear Fresnel lens shown in FIGS. The imaging position of the spatially floating image is determined by controlling the exit direction of the incident light flux. According to this configuration, the image light from the image display device 1 efficiently reaches the viewer with high directivity (straightness) like laser light, and as a result, high-quality floating images can be displayed with high quality. It is possible to display images with high resolution and to significantly reduce power consumption by the video display device 1 including the light source device 13.

<Example 1 of video display device>
FIG. 24 shows another example of a specific configuration of the video display device 1. The light source device 13 in FIG. 24 is similar to the light source device in FIG. 25 and the like. The light source device 13 is configured by housing an LED, a collimator, a synthetic diffusion block, a light guide, etc. in a case made of plastic, for example, and has a liquid crystal display panel 11 attached to its upper surface. Further, on one side 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 board on which their control circuits are mounted are attached, and on the outer side of the LED board, 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 addition, the liquid crystal display panel frame attached to the top surface of the case has a liquid crystal display panel 11 attached to the frame and an FPC (Flexible Printed Circuits) electrically connected to the liquid crystal display panel 11. ) (not shown), etc. are attached. That is, the liquid crystal display panel 11, which is a liquid crystal display element, together with the LED elements 14a and 14b, which are solid-state light sources, adjusts the intensity of transmitted light based on a control signal from a control circuit (not shown here) that constitutes an electronic device. A display image is generated by modulating the .

<Example 1 of light source device of Example 1 of video display device>
Next, 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. 25(a) and 25(b) as well as FIG. 23. 23 and 24 show LEDs 14a and 14b constituting the light source, which are attached to predetermined positions relative to the collimator 15. Note that each of the collimators 15 is made of a translucent resin such as acrylic. As shown in FIG. 22(b), this collimator 15 has an outer circumferential surface 156 with a conical convex shape obtained by rotating a parabolic cross section, and its center at the top (side in contact with the LED board). It has a concave portion 153 in which a convex portion (that is, a convex lens surface) 157 is formed.

Further, the central part of the flat part (the side opposite to the above-mentioned top part) of the collimator 15 has a convex lens surface (or a concave lens surface concave inward) 154 that projects outward. Note that the paraboloid 156 forming the conical outer circumferential surface of the collimator 15 is set within an angle range that allows total reflection of the light emitted from the LEDs 14a and 14b in the peripheral direction, or, A reflective surface is formed.

Further, the LEDs 14a and 14b are each placed at a predetermined position on the surface of the board 102, which is the circuit board. This substrate 102 is arranged and fixed to the collimator 15 such that the LEDs 14a or 14b on the surface thereof are located at the center of the recess 153, respectively.

According to this configuration, among the light emitted from the LED 14a or 14b by the collimator 15 described above, especially the light emitted upward (to the right in the figure) from the central portion thereof, the outer shape of the collimator 15 is The two convex lens surfaces 157 and 154 converge the light into parallel light. Further, light emitted from other parts toward the periphery is reflected by the paraboloid that forms the conical outer peripheral surface of the collimator 15, and is similarly condensed into parallel light. In other words, with the collimator 15 having a convex lens in the center and a paraboloid in the periphery, it is possible to extract almost all of the light generated by the LED 14a or 14b as parallel light. , it becomes possible to improve the utilization efficiency of the generated light.

Note that a polarization conversion element 21 is provided on the light output 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. 24(a), this polarization conversion element 21 consists of a columnar (hereinafter referred to as a parallelogram column) translucent member having a parallelogram cross section and a columnar member (hereinafter referred to as a parallelogram column) having a triangular cross section. , triangular prism), and are arranged in a plurality in an array parallel to a plane orthogonal to the optical axis of the parallel light from the collimator 15. Further, polarizing beam splitters (hereinafter abbreviated as "PBS films") 211 and reflective films 212 are alternately provided at the interfaces between adjacent light-transmitting members arranged in an array. Further, a λ/2 phase plate 213 is provided on the exit surface from which the light that has entered the polarization conversion element 21 and passed through the PBS film 211 exits.

The output surface of this polarization conversion element 21 is further provided with a rectangular synthetic diffusion block 16 as shown in FIG. 24(a). That is, the light emitted from the LED 14a or 14b becomes parallel light due to the action of the collimator 15, enters the composite diffusion block 16, is diffused by the texture 161 on the exit side, and then reaches the light guide 17.

The light guide 17 is a rod-shaped member with a substantially triangular cross section (see FIG. 24(b)) made of a translucent resin such as acrylic, and as is clear from FIG. A light guide light incident part (surface) 171 facing the output surface of the diffusion block 16 via the first diffuser plate 18a, a light guide light reflection part (surface) 172 forming a slope, and a second diffuser. A light guide light emitting portion (surface) 173 is provided, which faces the liquid crystal display panel 11, which is a liquid crystal display element, through the plate 18b.

As shown in FIG. 23, which is a partially enlarged view, the light guide light reflecting portion (surface) 172 of the light guide 17 has a large number of reflecting surfaces 172a and connecting surfaces 172b arranged in an alternating sawtooth shape. It is formed. The reflective surface 172a (line segment sloping upward to the right in the figure) forms αn (n: a natural number, for example, 1 to 130) with respect to the horizontal plane indicated by the dashed line in the figure. As an example, here αn is set to 43 degrees or less (however, 0 degrees or more).

The light guide entrance portion (surface) 171 is formed in a curved convex shape inclined toward the light source side. According to this, the parallel light from the output surface of the composite diffusion block 16 is diffused and incident through the first diffusion plate 18a, and as is clear from the figure, the light guide entrance part (surface) 171 As a result, the light is slightly bent (deflected) upward and reaches the light guide light reflecting portion (surface) 172, where it is reflected and reaches the liquid crystal display panel 11 provided on the emission surface in the upper part of the figure.

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 can be manufactured in a small size and at low cost, including a modular S-polarized light source device. It becomes possible. In the above explanation, the polarization conversion element 21 was explained as being attached after the collimator 15, but the present invention is not limited thereto, and the same effect can be obtained by providing it in the optical path leading to the liquid crystal display panel 11.・Effects can be obtained.

Note that the light guide light reflecting portion (surface) 172 has a large number of reflecting surfaces 172a and connecting surfaces 172b alternately formed in a sawtooth shape, and the illumination light flux is totally reflected on each reflecting surface 172a. Furthermore, a narrow-angle diffuser plate is provided on the light guide light emitting part (surface) 173, and the light enters the light direction conversion panel 54 that adjusts the directivity characteristics as a substantially parallel diffused light flux, and from an oblique direction. The light enters the liquid crystal display panel 11. The direction of the light emitted from the video display device 1 is controlled by a light direction conversion panel 54 provided on the top surface of the light source device 13. As a result, the light emitted from the liquid crystal display panel 11 is also controlled, and the direction of light diffusion of the spatially floating image obtained by the spatially floating image system using this image display device 1 is controlled. In this embodiment, the light direction conversion panel 54 is provided between the light guide output surface 173 and the liquid crystal display panel 11, but the same effect can be obtained even if it is provided on the output surface of the liquid crystal display panel 11.

In a typical TV device, the light emitted from the liquid crystal display panel 11 has, for example, the "conventional characteristic (X direction)" in FIG. 30(A) and the "conventional characteristic (Y direction)" in FIG. 30(B). '', the screen horizontal direction (display direction corresponding to the X-axis of the graph in FIG. 30(A)) and the screen vertical direction (display direction corresponding to the Y-axis of the graph in FIG. 30(B)) and have similar diffusion characteristics.

On the other hand, the diffusion characteristics of the emitted light flux from the liquid crystal display panel of this example are, for example, "Example 1 (X direction)" in FIG. 30(A) and "Example 1 (Y direction)" in FIG. 30(B). The diffusion characteristics will be as shown in the plot curve of ``direction)''.

In one specific example, if the viewing angle is set to 13 degrees at which the brightness is 50% of the brightness when viewed from the front (angle of 0 degrees) (brightness reduced by about half), The angle is approximately 1/5 of the diffusion characteristic (angle of 62 degrees) of a device for TV use. Similarly, in an example where the vertical viewing angle is set unevenly between the upper and lower sides, the upper viewing angle may be suppressed (narrowed) to about 1/3 of the lower viewing angle. , optimize the reflection angle of the reflective light guide, the area of the reflective surface, etc.

By setting the viewing angle, etc. as described above, compared to conventional LCD TVs, the amount of light in the image directed toward the user's viewing direction is significantly increased (significantly improved in terms of image brightness). The brightness of such an image is 50 times or more.

Furthermore, in the case of the viewing angle characteristics shown in "Example 2" in FIG. 30, the viewing angle is such that the brightness is 50% of the brightness of the image obtained when viewed from the front (angle of 0 degrees) (brightness reduced to approximately half). If it is set to be 5 degrees, the angle will be about 1/12 (narrow viewing angle) of the diffusion characteristic (angle of 62 degrees) of a typical home TV device. Similarly, in an example where the vertical viewing angle is set equally on the upper and lower sides, reflective type Optimize the reflection angle of the light guide and the area of the reflection surface.

By making these settings, the brightness (amount of light) of images directed toward the viewing direction (the direction of the user's line of sight) is significantly improved compared to conventional LCD TVs, and the brightness of such images is more than 100 times higher. .

As described above, by making the viewing angle a narrow angle, the amount of light directed toward the viewing direction can be concentrated, so the efficiency of light utilization is greatly improved. As a result, even if a liquid crystal display panel for general TV use is used, by adjusting the light diffusion characteristics of the light source device, it is possible to achieve a significant increase in brightness with the same power consumption, making it possible to achieve brightness for bright outdoor displays. It can be a video display device compatible with the system.

When using a large LCD panel, the light around the screen is directed inward toward the viewer when the center of the screen is directly facing the viewer, thereby increasing the overall brightness of the screen. will improve. FIG. 27 shows the long side of the liquid crystal display panel and the short side of the liquid crystal display panel when 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) are used as parameters. The diagram shown at the top, which shows the convergence angle of , is based on the assumption that the image is viewed with the screen of the liquid crystal display panel set vertically (hereinafter also referred to as "portrait"). In this case, the convergence angle may be set in accordance with the short side of the liquid crystal display panel (as appropriate, refer to the direction of arrow V in FIG. 27).

As a more specific example, as shown in the plot graph in FIG. 27, for example, when a 22" panel is used vertically and the viewing distance is 0.8 m, the convergence angle is set to 10 degrees. As a result, image light from each corner (four corners) of the screen can be effectively projected or output toward the viewer.

Similarly, when viewing a 15" panel vertically and the viewing distance is 0.8m, setting the convergence angle to 7 degrees will effectively direct the image light from the four corners of the screen toward the viewer. As mentioned above, depending on the size of the LCD panel and whether it is used vertically or horizontally, the image light around the screen can be directed to the viewer who is in the optimal position to view the center of the screen. , the overall screen brightness can be improved.

As shown in FIG. 30, the basic configuration is such that a light source device causes a light beam with a narrow directional characteristic to enter the liquid crystal display panel 11, and the brightness is modulated in accordance with the video signal. An image displayed on a screen is reflected by a retroreflective member, and a floating image obtained in space is displayed outdoors or indoors via a transparent member 100.

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

When using a large LCD panel, as mentioned above, the brightness of the screen can be increased by directing the light around the screen inward toward the viewer when the center of the screen is directly facing the viewer. However, on the other hand, binocular parallax occurs depending on whether the viewer uses the left or right eye to view the image. FIG. 28 shows the convergence of the long side of the liquid crystal display panel and the short side of the liquid crystal display panel when 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) are used as parameters. The angle is determined based on the positions of the left and right eyes.

The smaller the panel size and the closer the viewing distance, the larger the convergence angle in binocular vision between the left and right eyes. Especially when using a small panel of 7 inches or less, the convergence angle due to binocular parallax is an important requirement. It is designed so that the image light is directed to the optimum viewing range of the system.

Furthermore, depending on the required specifications of the system, it is necessary to optimally design the shape, surface roughness, inclination, etc. of the reflective surface of the light guide of the light source device 13 in order to obtain horizontal and vertical directivity characteristics and diffusion characteristics. be.

<Example 1 of light source device>
Next, another example of the light source device will be described with reference to FIG. 19. 19(a) and (b) are diagrams in which a portion of the liquid crystal display panel 11 and the diffusion plate 206 are omitted in order to explain the light guide 311. FIG.

FIG. 19 shows a state in which the LED 14 constituting the light source is attached to the substrate 102. These LEDs 14 and substrate 102 are attached to the reflector 15 at predetermined positions.

As shown in FIG. 19(a), the LEDs 14 are arranged in a line in a direction parallel to the side (short side in this example) of the liquid crystal display panel 11 on which the reflector 300 is arranged. In the illustrated example, a reflector 300 is arranged corresponding to the arrangement of the LEDs. Note that a plurality of reflectors 300 may be arranged.

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

As shown in FIG. 19(b), the inner surface of the reflector 300 (on the right side in the figure) is a reflecting surface in the shape of a paraboloid cut along the meridian plane (hereinafter sometimes referred to as a "paraboloid"). ) 305. The reflector 300 converts the diverging light emitted from the LED 14 into substantially parallel light by reflecting it on the reflecting surface 305 (paraboloid), and the converted light enters the end surface of the light guide 311. let In one specific example, light guide 311 is a transmissive light guide.

The reflective surface of the reflector 300 has an asymmetric shape with respect to the optical axis of the light emitted from the LED 14. Further, the reflective surface 305 of the reflector 300 is a paraboloid as described above, and by arranging the LED at the focal point of the paraboloid, the reflected light beam is converted into substantially parallel light.

Since the LED 14 is a surface light source, the diverging light from the LED cannot be converted into completely parallel light even if it is placed at the focal point of a paraboloid, 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. In addition, in order to ensure the specified performance with the mounting accuracy of the LED 14 on the board 102 of ±40 μm, the number of LEDs mounted on the board should be no more than 10 at most, and if mass production is considered, it should be kept to about 5. Good.

Although the LED 14 and the reflector 300 are partially located close to each other, heat can be radiated to the space on the opening side of the reflector 300, so the temperature rise of the LED can be reduced. Therefore, the reflector 300 made of plastic molding can be used. As a result, according to this reflector 300, the shape precision of the reflecting surface can be improved by more than 10 times compared to a reflector made of glass material, so that the light utilization efficiency can be improved.

On the other hand, a reflective surface is provided on the bottom surface 303 of the light guide 311, and the light from the LED 14 is converted into a parallel beam by the reflector 300, then reflected by the reflective surface, and is placed opposite the light guide 311. The light is emitted toward the liquid crystal display panel 11. The reflective surface provided on the bottom surface 303 may have a plurality of surfaces having different inclinations in the traveling direction of the parallel light beam from the reflector 300, as shown in FIG. Each of the plurality of surfaces having different inclinations may have a shape extending in a direction perpendicular to the traveling direction of the parallel light beam from the reflector 300.

Further, the shape of the reflective 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 reflective surface provided on the bottom surface 303 of the light guide 311, so that the liquid crystal display panel 11 It is possible to adjust the amount of light and the direction of emission of the light beam toward the target with high precision. As a result, the amount and direction of light incident on the liquid crystal display panel 11 and light emitted from the liquid crystal display panel 11 can be controlled with high precision, so that a floating image can be displayed using a video display device using this light source. In the system, the direction and angle of diffusion of the image light of the spatially floating image can be set to desired values.

As shown in FIGS. 19(a) and 19(b), the refractive surface 314 may have a plurality of surfaces having different inclinations in the traveling direction of the parallel light beam from the reflector 300. Each of the plurality of surfaces having 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 inclinations of the plurality of surfaces cause the light reflected by the reflective surface provided on the bottom surface 303 of the light guide 311 to be refracted toward the liquid crystal display panel 11 . Further, the refraction surface 314 may be a transmission surface.

Note that when the diffuser plate 206 is provided in front of the liquid crystal display panel 11, the light reflected by the reflective surface is refracted toward the diffuser plate 206 by the plurality of inclinations of the refracting surface 314. That is, the extending direction of the plurality of surfaces having different inclinations of the refractive surface 314 and the extending direction of the plurality of surfaces having different inclinations of the reflective surface provided on the bottom surface 303 are parallel. By making both stretching directions parallel, the angle of light can be adjusted more suitably. On the other hand, the LED 14 is soldered to the metallic substrate 102. Therefore, the heat generated by the LED can be radiated into the air through the substrate.

Further, the reflector 300 may be in contact with the substrate 102, but a space may be left open. When opening a space, the reflector 300 is placed in a state where it is adhered to the casing. By leaving the space open, the heat generated by the LED can be dissipated into the air, increasing the cooling effect. As a result, the operating temperature of the LED can be reduced, making it possible to maintain luminous efficiency and extend the lifespan.

<Another example 2 of light source device>
Next, FIGS. 20A, 20B, 20C, and 20D show the configuration of an optical system for a light source device that uses polarization conversion to improve light utilization efficiency by 1.8 times compared to the light source device shown in FIG. 19. This will be explained in detail with reference to the following. Note that the illustration of the sub-reflector 308 is omitted in FIG. 20A.

20A, FIG. 20B, and FIG. 20C show a state in which the LED 14 constituting the light source is attached to the substrate 102, and these are configured by a unit 312 having a plurality of blocks, including a reflector 300 and the LED 14 as a pair of blocks. .

Among these, the base material 320 shown in FIG. 20A(2) is the base material of the substrate 102. Generally, the metallic substrate 102 has heat, so in order to insulate (insulate) the heat of the substrate 102, the base material 320 is preferably made of a plastic material or the like. The material of the reflector 300 and the shape of the reflecting surface may be the same as those of the example of the light source device in FIG. 28 .

Furthermore, the reflective surface of the reflector 300 may have an asymmetric shape with respect to the optical axis of the light emitted from the LED 14. The reason for this will be explained with reference to FIG. 20A(2). In this embodiment, the reflective surface of the reflector 300 is a paraboloid, as in the example of FIG. 19, and the center of the light emitting surface of the LED, which is a surface light source, is placed at the focal point of the paraboloid.

Further, 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 the only difference is the emission direction. Therefore, even if the light emitting section has a large area, the amount of light incident on the polarization conversion element 21 and the conversion efficiency are hardly affected as long as the distance between the polarization conversion element disposed at the subsequent stage and the reflector 300 is short.

Moreover, even if the mounting position of the LED 14 is shifted in 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 above-mentioned reasons. Furthermore, even if 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, a reflector 300 having a reflecting surface formed by cutting out a part of a paraboloid in a meridian direction has been described, but an LED may be placed in a part of the entire paraboloid which is cut out as a reflecting surface.

On the other hand, in this embodiment, as shown in FIGS. 20B(1) and 20C, after the diverging light from the LED 14 is reflected by the paraboloid 321 and converted into substantially parallel light, the polarization conversion element 21 in the subsequent stage is The characteristic configuration is that the light is made incident on the end face and aligned to a specific polarization by the polarization conversion element 21. Due to this characteristic configuration, in this example, the light utilization efficiency is 1.8 times that of the example shown in FIG. 26 described above, and a highly efficient light source can be realized.

Note that at this time, the substantially parallel light obtained by reflecting the diverging light from the LED 14 on the paraboloid 321 is not all uniform. Therefore, by adjusting the angular distribution of the reflected light using the reflective surfaces 307 having a plurality of inclinations, the reflected light can be directed toward the liquid crystal display panel 11 in a direction perpendicular to the liquid crystal display panel 11 .

In the example shown in this figure, the arrangement is such that the direction of light (principal ray) entering the reflector from the LED and the direction of light entering the liquid crystal display panel are approximately 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 escapes upward and the temperature rise of the LED can be reduced.

In addition, as shown in FIG. 20B (1), in order to improve the capture rate of the diverging light from the LED 14, the light flux that cannot be captured by the reflector 300 is reflected by the sub-reflector 308 provided on the light shielding plate 309 disposed above the reflector. The light is reflected by the slope of the lower sub-reflector 310 and enters the effective area of the polarization conversion element 21 in the subsequent stage, further improving 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.

A substantially parallel light beam aligned to a specific polarization by the polarization conversion element 21 is reflected by a reflection shape provided on the surface of the reflective light guide 306 toward the liquid crystal display panel 11 disposed opposite the light guide 306. Ru. At this time, the light intensity distribution of the light beam incident on the liquid crystal display panel 11 is optimally designed based on the shape and arrangement of the reflector 300 described above, the shape of the reflective surface (cross-sectional shape) of the reflective light guide, the inclination of the reflective surface, and the surface roughness. be done.

As for the shape of the reflective surface provided on the surface of the light guide 306, a plurality of reflective surfaces are arranged facing the output surface of the polarization conversion element, and the inclination and area of the reflection surface are adjusted depending on the distance from the polarization conversion element 21. , height, and pitch, the light intensity distribution of the light flux incident on the liquid crystal display panel 11 can be set to a desired value, as described above.

By configuring the reflective surface 307 provided on the reflective light guide so that one surface has multiple inclinations, as shown in FIG. 20B (2), it is possible to adjust the reflected light with higher precision. . In addition, in a structure in which the reflective surface has a plurality of inclinations on one surface, the area used as the reflective surface may be a plurality of surfaces, a polysurface, or a curved surface. Furthermore, the diffusion effect of the diffusion plate 206 realizes a more uniform light amount distribution. The light incident on the diffuser plate on the side closer to the LED achieves a uniform light intensity distribution by changing the inclination of the reflecting surface. As a result, the amount of light and the direction of emission of the light beam directed toward the liquid crystal display panel 11 can be adjusted with high precision. As a result, the amount and direction of light incident on the liquid crystal display panel 11 and light emitted from the liquid crystal display panel 11 can be controlled with high precision, so that a floating image can be displayed using a video display device using this light source. In the system, the direction and angle of diffusion of the image light of the spatially floating image can be set to desired values.

In this embodiment, the base material of the reflective surface 307 is made of a plastic material such as heat-resistant polycarbonate. Further, the angle of the reflecting surface 307 immediately after the light is emitted from the λ/2 plate 213 changes depending on the distance between the λ/2 plate and the reflecting surface.

In this embodiment as well, although the LED 14 and the reflector 300 are partially located close to each other, heat can be radiated to the space on the opening side of the reflector 300, thereby reducing the temperature rise of the LED. Further, the substrate 102 and the reflector 300 may be arranged upside down as shown in FIGS. 20A, 20B, and 20C.

However, if the substrate 102 is placed on top, the substrate 102 will be close to the liquid crystal display panel 11, which may make layout difficult. Therefore, as shown in the figure, if the substrate 102 is placed below the reflector 300 (on the side far from the liquid crystal display panel 11), the internal configuration of the device will be simpler.

A light shielding plate 410 may be provided on the light incidence surface of the polarization conversion element 21 to prevent unnecessary light from entering the subsequent optical system. With such a configuration, a light source device that suppresses temperature rise can be realized. The polarizing plate provided on the light incident surface of the liquid crystal display panel 11 reduces the temperature rise by absorbing the uniformly polarized light beam of the present invention, but when it is reflected by the reflective light guide, the polarization direction rotates and some The light is absorbed by the polarizing plate on the incident side. Furthermore, the temperature of the liquid crystal display panel 11 also rises due to absorption by the liquid crystal itself and temperature rise due to light incident on the electrode pattern, but if there is sufficient space between the reflective surface of the reflective light guide 306 and the liquid crystal display panel 11. Yes, natural cooling is possible.

FIG. 20D is a modification of the light source device in FIGS. 20B(1) and 20C. FIG. 20D(1) shows a modified example of a part of the light source device of FIG. 20B(1). The other configurations are the same as the light source device described above in FIG. 20B(1), so illustration and repeated description will be omitted.

First, in the example shown in FIG. 20D(1), the height of the recess 319 of the sub-reflector 310 is such that the principal ray of fluorescence outputted laterally (X-axis direction) from the phosphor 114 (X in FIG. 20D(1)) (see a straight line extending in a direction parallel to the axis) is adjusted to be at a position lower than the phosphor 114 so that it passes through the recess 319 of the sub-reflector 310. Furthermore, in the Z-axis direction with respect to the position of the phosphor 114, so that the principal ray of fluorescence outputted laterally from the phosphor 114 enters the effective area of the polarization conversion element 21 without being blocked by the light shielding plate 410. The height of the light shielding plate 410 is adjusted to be low.

Further, the reflective surface of the uneven convex portion on 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 that the light reflected by the sub-reflector 308 is reflected and enters the effective area of the polarization conversion element 21 in the subsequent stage, thereby further improving the light utilization efficiency. can be improved.

Note that, as shown in FIG. 20A(2), the sub-reflector 310 is arranged to extend in one direction, and has an uneven shape. Further, on the top of the sub-reflector 310, irregularities having one or more recesses are periodically arranged in one direction. By forming such an uneven shape, it is possible to configure such that the chief ray of fluorescence outputted laterally from the phosphor 114 enters the effective area of the polarization conversion element 21.

Further, the uneven shape of the sub-reflector 310 is arranged periodically at a pitch such that the recesses 319 are located at the positions where the LEDs 14 are located. That is, each of the phosphors 114 is arranged periodically along one direction corresponding to the arrangement pitch of the concave and convex portions of the sub-reflector 310. In addition, when the phosphor 114 is included in the LED 14, the phosphor 114 may be expressed as a light emitting part of a light source.

Further, FIG. 20D(2) shows a modified example of a part of the light source device of FIG. 20C. The other configurations are the same as those of the light source device in FIG. 20C, so illustration and repeated description will be omitted. As shown in FIG. 20D(2), the sub-reflector 310 may not be provided, but as in FIG. 20D(1), the principal ray of fluorescence outputted laterally from the phosphor 114 is not blocked by the light shielding body 410. 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 light enters the effective area of the polarization conversion element 21.

Regarding the light source devices in FIGS. 20A, 20B, 20C, and 20D, as shown in FIG. A side wall 400 may be provided to prevent stray light from entering, to prevent stray light from occurring 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.

The light exit 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 diffuser plate 206, and the polarization conversion element 21. In addition, a portion of the inner surface of the side wall 400 that covers from the side the space where light is output from the output surface of the polarization conversion element 21 (the space on the right side from the output surface of the polarization conversion element 21 in FIG. 20B(1)) A reflective surface having a reflective film or the like is used as the surface. That is, the surface of the side wall 400 facing the space includes a reflective region having a reflective film. By making the part of the inner surface of the side wall 400 a reflective surface, the light reflected by the reflective surface can be reused as light source light, and the brightness of the light source device can be improved.

Of the inner surfaces of the side wall 400, the surface that covers the polarization conversion element 21 from the side is a surface with low light reflectance (such as a black surface without a reflective film). This is because when reflected light occurs on the side surface of the polarization conversion element 21, light with an unexpected polarization state is generated, causing stray light. In other words, by making the above-mentioned surface a surface with low light reflectance, it is possible to prevent or suppress the generation of stray light in an image and light with an unexpected polarization state. Further, the cooling effect may be improved by providing a hole in a part of the side wall 400 through which air passes.

Note that the light source devices in FIGS. 20A, 20B, 20C, and 20D have been described on the assumption that the polarization conversion element 21 is used. 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.

<Another example 3 of light source device>
Next, the configuration of an optical system related to a light source device using a reflective light guide 304 based on the light source device shown in Example 1 of the light source device is shown in FIGS. 21A(1), (2), (3), and FIG. This will be explained in detail with reference to 21B.

FIG. 21A shows a state in which the LED 14 constituting the light source is mounted on the substrate 102, and the collimator 18 and the LED 14 form a pair of blocks, and the unit 328 has a plurality of blocks. Since the collimator 18 of this embodiment is close to the LED 14, a glass material is used in consideration of heat resistance. The shape of the collimator 18 is similar to the shape described for the collimator 15 in FIG. 20. Furthermore, by providing a light shielding plate 317 before entering the polarization conversion element 21, unnecessary light is prevented or suppressed from entering the optical system at the subsequent stage, and temperature rise due to the unnecessary light is reduced. .

The other configurations and effects of the light source shown in FIG. 21A are the same as those in FIGS. 20A, 20B, 20C, and 20D, so repeated explanations will be omitted. The light source device in FIG. 21A may be provided with a side wall, similar to those described in FIGS. 20A, 20B, and 20C. The configuration and effects of the side walls have already been explained, so repeated explanations will be omitted.

FIG. 21B is a cross-sectional view of FIG. 21A(2). The structure of the light source shown in FIG. 21B is common to a part of the structure of the light source shown in FIG. 20, and has already been explained in FIG. 18, so repeated explanation will be omitted.

<Another example 4 of light source device>
Next, the light source device of FIG. 25 is constituted by a unit 328 having a plurality of blocks in which the collimator 18 and the LED 14 used in the light source device shown in FIG. 21 form a pair of blocks. The configuration of the optical system related to the light source device using the LEDs and the reflective light guide 504 arranged at both ends of the back surface of the liquid crystal display panel 11 will be explained in detail with reference to FIGS. 25(a), (b) and (c). explain.

FIG. 25 shows a state in which the LEDs 14 constituting the light source are mounted on a substrate 505, and these are constituted by a unit 503 having a plurality of blocks each including a collimator 18 and an LED 14 as a pair of blocks. The units 503 are 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 incident on the liquid crystal display panel 11 (shown in FIG. 25(c)) arranged opposite to each other.

As shown in FIG. 25(c), the reflective light guide 504 is divided into two blocks corresponding to the units arranged at each end, and arranged so that the central part is the highest. Since the collimator 18 is close to the LED 14, a glass material is used in consideration of heat resistance to the heat emitted from the LED 14. The shape of the collimator 18 is the same as that described for the collimator 15 in FIG.

The light from the LED 14 enters the polarization conversion element 501 via the collimator 18. The configuration is such that the shape of the optical element 81 adjusts the distribution of light incident on the reflective light guide 504 at the subsequent stage. That is, the light intensity distribution of the luminous flux incident on the liquid crystal display panel 11 depends on the shape of the collimator 18, the arrangement, the shape of the optical element 81, the diffusion characteristics, and the shape of the reflective surface (cross-sectional shape) of the reflective light guide. Optimal design is achieved by adjusting the inclination of the reflective surface and the surface roughness of the reflective surface.

The shape of the reflective surface provided on the surface of the reflective light guide 504 is as shown in FIG. Optimize the tilt, area, height, and pitch of the reflective surface according to the distance.

In addition, by dividing the area serving as the same reflective surface (that is, the surface facing the polarization conversion element) into polyhedrons, the light intensity distribution of the light beam incident on the liquid crystal display panel 11 can be set to a desired value (optimal can be converted into Therefore, the amount of light and the direction of emission of the light beam toward the liquid crystal display panel 11 can be adjusted with high precision. As a result, the amount and direction of light incident on the liquid crystal display panel 11 and light emitted from the liquid crystal display panel 11 can be controlled with high precision, so that a floating image can be displayed using a video display device using this light source. In the system, the diffusion direction and diffusion angle of the image light of the spatially floating image can be set to desired values (see the four solid line arrows indicating "reflected light from the light guide" in FIG. 26).

Similar to the reflective light guide described in FIG. 20B, the reflective surface provided on the reflective light guide has a configuration in which one surface (the area where light is reflected) has a shape with multiple inclinations (see FIG. In the example of No. 25, the reflected light can be adjusted with higher precision by dividing the XY plane into 14 parts and configuring them with different inclined surfaces. In addition, 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 light from leaking in a direction other than the desired direction (direction toward the liquid crystal display panel 11). can be prevented from occurring.

Furthermore, the units 503 placed on the left and right sides of the reflective light guide 504 in FIG. 25 may be replaced with the light source device in FIG. 20. That is, a plurality of light source devices (substrate 102, reflector 300, LED 14, etc.) shown in FIG. 20 are prepared, and the plurality of light source devices are connected to each other as shown in FIGS. It is also possible to have a configuration in which they are placed at opposing positions.

FIG. 26(B) shows a light source device configured by arranging six units 503 shown in FIG. 26(A) in the upper part and six units in the lower part. The light source device shown in FIG. 26(B) has a configuration in which a unit 503 in which five LEDs are arranged horizontally is arranged as described above, and a desired brightness is obtained by controlling the current with a single power source. Therefore, as a light source device for illuminating a liquid crystal panel, the light source brightness can be controlled for each area illuminated by each unit 503.

The configuration shown in FIG. 26 includes a reflective surface 222 and a reflective surface 502 different from the reflective surface 222. Of these, the reflective surface 222 has a horizontal lattice-like shape or a band shape with a predetermined width. On the other hand, the reflective surface 502 has a shape like a vertical and horizontal lattice. By optimally designing the shape of these fine gratings and the inclination of the dividing plane, a desired output light distribution (the output direction and diffusion characteristics of the output light) can be obtained.

As a result, even if a single light source is used for the flat display and the spatially floating image display device shown in FIGS. 16 and 17, the amount and direction of the light beam directed toward the liquid crystal display panel 11 can be adjusted with high precision. As a result, similarly to the two embodiments described above, the amount and direction of light incident on the liquid crystal display panel 11 and the light emitted from the liquid crystal display panel 11 can be controlled with high precision. In a spatially floating video display system using a video display device, the diffusion direction and diffusion angle of image light of a spatially floating video can be set to desired values.

FIG. 22 is a cross-sectional view showing an example of the shape of the diffusion plate 206. As described above, the diverging light output from the LED is converted into substantially parallel light by the reflector 300 or the collimator 18, converted into a specific polarized light 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 part of the incident surface of the diffuser plate 206 and enters the liquid crystal display panel 11 (two lines indicating "reflected light from the light guide" in FIG. 22) (see solid arrow).

Further, among the light emitted from the polarization conversion element 21 , a diverging luminous flux is totally reflected on the slope of a protrusion having an inclined surface provided on the incident surface of the diffuser plate 206 and enters the liquid crystal display panel 11 . In order to cause the light emitted from the polarization conversion element 21 to be totally reflected on the slope of the projection of the diffuser plate 206, the angle of the slope of the projection is changed based on the distance from the polarization conversion element 21. When the angle of the slope 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 slope 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'). With such a setting, it becomes possible to effectively utilize the polarized light flux.

<Diffusion characteristic control technology for video display devices>
As a method of adjusting the diffusion distribution of image light from the liquid crystal display panel 11, a lenticular lens is 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 is optimized. One example is to become That is, by optimizing the shape of the lenticular lens, the emission characteristics of the image light (hereinafter also referred to as "image light flux") emitted from the liquid crystal display panel 11 in one direction can be adjusted.

Alternatively or additionally, the 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 mode of arrangement may be adjusted. That is, by adjusting the arrangement of the microlens array, it is possible to adjust the emission characteristics of the image light flux emitted from the image display device 1 in the X-axis and Y-axis directions, and as a result, desired diffusion characteristics can be obtained. It is possible to obtain a video display device having the following.

As a further configuration example, a combination of two lenticular lenses may be arranged at a position through which the image light emitted from the image display device 1 passes, or a microlens array may be arranged in a matrix to adjust the diffusion characteristics. A sheet may also be provided. By configuring the optical system like this, the brightness (relative brightness) of the image light in the X-axis and Y-axis directions can be adjusted to the reflection angle of the image light (with the case of reflection in the vertical direction as the standard (0 degrees)). reflection angle).

In this example, 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. 29(b), , it is possible to obtain excellent optical characteristics that are clearly different from conventional characteristic graphs (plot curves). Specifically, in the plot curves of Example 1 (Y direction) and Example 2 (Y direction), the brightness characteristics in the vertical direction are made steeper, and the balance of the directional characteristics in the vertical direction (positive and negative directions of the Y axis) is further changed. By doing so, the brightness (relative brightness) of light due to reflection and diffusion can be increased.

Therefore, according to this embodiment, the image light has a narrow diffusion angle (high straightness) and has only a specific polarization component, like image light from a surface-emitting laser image source, and the image display device according to the prior art It is possible to suppress the ghost image that would occur in the retroreflective member when using the retroreflection member, and to make adjustments so that the spatially floating image due to retroreflection can be efficiently delivered to the viewer's eyes.

In addition, the above-mentioned light source device allows the X-axis It is possible to provide a directional characteristic with a significantly narrow angle in both the direction and the Y-axis direction. In this embodiment, by providing such a narrow-angle directivity characteristic, it is possible to realize an image display device that emits a nearly parallel image light beam in a specific direction and emits light of a specific polarization. .

FIG. 30 shows an example of the characteristics of the lenticular lens employed in this example. This example particularly shows the characteristics in the X direction (vertical direction) with respect to the Z axis, and the characteristic O is that the peak of the light emission direction is at an angle of around 30 degrees upward from the vertical direction (0 degrees). , and exhibits vertically symmetrical brightness characteristics. Furthermore, the plot curves of characteristics A and B shown in the graph of FIG. 30 further show examples of characteristics in which the image light above the peak brightness is focused around 30 degrees to increase the brightness (relative brightness). There is. Therefore, in these characteristics A and B, as can be seen by comparing with the plot curve of characteristic O, the angle where the inclination (angle θ) from the Z axis to the X direction exceeds 30 degrees (θ > 30 degrees) In the region, the brightness (relative brightness) of light decreases rapidly.

That is, according to the optical system including the above-mentioned lenticular lens, when the image light flux from the image display device 1 is incident on the retroreflective member, the output angle and viewing angle of the image light aligned at an included angle by the light source device 13 are adjusted. can be adjusted, greatly increasing the degree of freedom in installing retroreflective sheets. As a result, the degree of freedom regarding the image formation position of the spatially floating image that is reflected or transmitted through the window glass and formed at a desired position can be greatly improved. As a result, it becomes possible to efficiently reach the eyes of a viewer outdoors or indoors as light with a narrow diffusion angle (high straightness) 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 video display device 1, it is possible to realize a display system with low power consumption.

<Another example of a floating video display device>
This embodiment is a system that can simultaneously display images from a plurality of specific directions, and can operate the display image with high precision in response to the plurality of displayed spatial images. In the spatial floating video display system or spatial floating video display device of this embodiment, a retroreflective member 5 having a reflective surface as shown in FIG. 36 is used. This retroreflective member 5 has a two-layer structure, upper and lower.

Furthermore, as the image display device, the above-mentioned light source device whose directional characteristics and diffusion characteristics can be controlled is used. At this time, a display panel (liquid crystal panel or liquid crystal display panel) from which image light of a specific polarization can be obtained is used as an image source capable of high-resolution color display as an image display device. Effects unique to this embodiment can be obtained by allowing the image light from the liquid crystal display panel 1 having narrow-angle diffusion characteristics to be incident on the retroreflection member 5 used in the spatially floating image display device of this embodiment. Further, the specific technical means for imparting narrow-angle diffusion characteristics to the light source, which is essential for realizing this embodiment, has been described above.

In this embodiment, as shown in FIGS. 37(A) and 37(B), image light from the display panel 11 of the image display device 1 is transferred to the planar light reflecting section 220 of the light control panel 221 of the retroreflection member 5 and the light control panel. The reflected light is reflected twice by the planar light reflecting section 220 of the light control panel 222, and the reflected light creates the first spatially floating image 3 as a normal real image in the air, and is reflected once by the planar light reflecting section 220 of the light control panel 222 on both sides. A second space-floating image 3c caused by the light control panel 221 and a third space-floating image 3d caused by one reflection from the plane light reflecting section 220 of the light control panel 221 are displayed.

The space floating image includes a first space floating image and a plurality of space floating images formed at specific angles and distances with respect to the first space floating image. In this embodiment, as shown in FIGS. 37(A) and 37(B), the spatial floating images include a spatial floating image 3 floating in the center, and a specific angle left and right with respect to the spatial floating image 3 floating in the center. There are spatially floating images 3c and 3d formed at a distance from the central spatially floating image 3, and the angle formed by the central spatially floating image 3 and the spatially floating images 3c formed on the left and right, and the central spatially floating image 3 formed on the left and right. The angle formed by the space floating image 3d is adjusted by the intersection angle between the light reflecting section 220 of the light control panel 221 of the retroreflection member 5 and the light reflecting section 220 of the light control panel 222. Further, the brightness of the spatially floating image floating in the center is about 50% of the brightness of the other spatially floating images.

The retroreflective member 5 used at this time consists of a first light control panel 221 and a second light control panel 222, as shown in FIG. , 17 are formed by arranging optical members 20 having a large number of band-shaped planar light reflecting portions 220 at a constant pitch perpendicularly to one side surface of the optical members 20 .

Here, the planar light reflecting section 220 of the optical member 20 constituting the first light control panel 221 and the planar light reflecting section 220 of the optical member 20 constituting the second light control panel 222 are arranged in a criss-cross manner. In this embodiment, the planar light reflecting portions 220 are arranged orthogonally. In this embodiment, the planar light reflection section 220 of the first light control panel 221 is referred to as a first reflection section, and the planar light reflection section 220 of the second light control panel 222 is referred to as a second reflection section. Further, an absorbing polarizing sheet 101 may be placed on the surface of the retroreflective member 5 on the side of the spatially floating image 3, or an absorbing polarizing sheet 101 may be placed between the retroreflective member 5 and the display panel 11 in order to adjust the emission direction of the image light. A polarizing sheet 101 may also be provided.

Next, the function of the retroreflective member 5 used in the space floating video display device of this embodiment and a specific example of the space floating video display device will be described. As shown in FIG. 36(B), the retroreflective member 5 is generally arranged at an angle of 40 to 50 degrees with respect to the image display device 1. At this time, the spatially floating image 3 is emitted from the retroreflective member 5 at the same angle as the angle at which the image light is incident on the retroreflective member 5. At this time, the spatially floating image is formed at a symmetrical position separated by the same distance L1 between the image display device 1 and the retroreflective member 5.

Hereinafter, the mechanism of forming a spatially floating image will be explained in detail using FIG. 36. The image light emitted from the image display device 1 provided on one side of the retroreflective member 5 is reflected by the planar light reflecting portion C of the second light control panel 222, and then reflected by the planar light reflecting portion C of the first light control panel 221. By being reflected by the light reflecting portion C', the space floating image 3 is imaged at a position outside the retroreflective member 5 (space on the other side). That is, by using this retroreflective member 5, the image of the video display device 1 can be displayed in space as a spatially floating image.

As shown in FIGS. 36(A) and 36(B), in the retroreflective member 5 described above, there are two reflecting parts as described above, so in addition to the space floating image 3, there are two space floating images due to one reflection. Images 3c and 3d are generated. The spatial floating image to be generated in addition to the spatial floating image 3 is determined according to the number of light control panels and the intersecting angle of the planar light reflector 220. The spatial floating images 3c and 3d obtained by this single reflection have twice the brightness compared to the spatial floating image 3 obtained after reflection from two reflective surfaces, and the floating images 3c and 3d obtained by the single reflection are twice as bright. Since the position of the image and the direction in which the image light diverges are different from those of the space floating image 3 described above, the viewing range in which the viewer can view the space floating image can be expanded.

The mechanism will be described in detail below. FIG. 37(B) shows the positions of the floating images 3c and 3d formed on both sides of the above-mentioned floating image 3. In FIG. 37(B), a space floating image 3, a space floating image 3c, and a space floating image 3d are displayed from the opening of the housing 800. A person viewing the spatial floating image 3 is positioned in front of the spatial floating image 3 and views the spatial floating image 3 by directing the line of sight P. At this time, the image light from the space floating image 3 is controlled by the narrow-angle diffusion characteristic of the light source device 13, and is set within a range of ±30° in the horizontal direction and ±15° in the vertical direction. Achieves high brightness.

On the other hand, the image light reflected into space after being reflected only once by the retroreflection member 5 forms a space floating image 3c and a space floating image 3d having twice the brightness of the space floating image 3. These two spatially floating images can only be viewed from specific directions. For example, the spatially floating image 3c can be viewed only from the viewing direction Q, while the spatially floating image 3d can only be viewed from the viewing direction R. Therefore, in addition to the regular floating image 3, the floating images 3c and 3d can be viewed from two sides.

As a result, the viewing range of spatially floating images can be greatly expanded. At this time, the diffusion angle of the three spatially floating images obtained can be controlled by the narrow-angle directivity characteristics and diffusion characteristics of the light source device included in the image display device described above.

Furthermore, the positions where the spatially floating images 3c and 3d formed by one-time reflection on both sides of the spatially floating image 3 are determined by the two light control panels 221 forming the retroreflective member 5 shown in FIG. 36(A). , 222 in a plan view shown in FIG. 36(B), the difference is made by changing the design using the intersecting angle and the distance between the two members as parameters. As shown in FIG. 37(B), the angle between the space floating image 3 and the space floating image 3c is θ10, and the angle between the space floating image 3 and the space floating image 3d is θ11, as shown in FIG. 36(A). The angle formed by the plane light reflection section 220 of the light control panel 221 and the plane light reflection section 220 of the light control panel 222 is defined as the intersection angle.

In order to increase the angles θ10 and θ11, the intersection angle is increased with respect to 90 degrees, and on the other hand, in order to decrease the angles θ10 and θ11, the above-mentioned intersection angle is made smaller with respect to the reference 90 degrees. However, if this intersection angle is shifted by ±10 degrees or more from 90 degrees, the light utilization efficiency will decrease and the brightness of the spatially floating image will be lowered, so it is preferable to set the angle optimally depending on the application. Furthermore, if the distance between the two light control panels is increased beyond a predetermined distance, the sense of focus and brightness of the floating image will decrease, so it is best to select an optimal value.

In addition, the display panel that generates the image displayed as a floating image has been added with brightness gradation processing from the center of the screen to the periphery to create a pseudo three-dimensional image. becomes possible. As the gradation process, the images displayed on the display panel are adjusted so that the brightness of the peripheral parts of the spatially floating images 3, 3c, and 3d is lower than that of the center. Further, the light source that supplies light to the display panel may be adjusted so that the brightness of the peripheral part of the spatially floating image is lower than that of the center part. In addition, a device may be provided to manipulate display images with high precision for the second spatially floating image 3c and the third spatially floating image 3d.

In order to make the above-mentioned three spatial floating images appear more three-dimensional, the inventors studied using an actual device and decided to adjust the brightness of the image displayed at the periphery of the screen to the image displayed at the center of the screen. We have found that by reducing the image displayed in the image, it is possible to emphasize the pop-up feeling of the image floating in space. By grading the brightness in the left and right directions from the center of the screen and darkening the periphery, you can emphasize the bulge in the center.If you set this brightness gradient so that the periphery is 10% or more darker than the center, a strong three-dimensional effect will be created. If it exceeds 35%, it will become too dark, so it is best to select within this range. Further, the slope of the brightness gradient can be understood as a function of the image display position with respect to the center of the screen, and changing it like a quadratic function gives a more three-dimensional effect than changing it like a linear function.

Furthermore, in order to emphasize the three-dimensional effect, it is recommended to apply a brightness gradient in the vertical direction as well, and in this case, as in the horizontal direction, it is good to reduce the brightness in the peripheral area relative to the center of the screen, and this brightness gradient is 10% relative to the center. If the peripheral area is made darker than above, the three-dimensional effect will be strong, and if it exceeds 35%, it will become too dark, so it is best to select within this range. Further, the slope of the brightness gradient can be understood as a function of the image display position with respect to the center of the screen, and changing it like a quadratic function gives a more three-dimensional effect than changing it like a linear function.

On the other hand, experiments have shown that it is most effective to have a brightness gradient that matches the displayed image, and that the three-dimensional effect can be further enhanced by emphasizing the brightness gradient according to the direction in which the light hits and the intensity of reflection on the light irradiation surface. It became clear.

As mentioned above, the second and third spatially floating images can be displayed with high brightness compared to the first spatially floating image using a spatial image display device that can provide sufficient brightness even when viewed from an oblique direction. realizable. Furthermore, it is possible to obtain a spatially floating image with a pseudo-stereoscopic viewing range expanded, and at the same time, it is possible to perform operation input without directly touching the display screen.

Various embodiments and examples (ie, specific examples) to which the present invention is applied have been described in detail above. On the other hand, the present invention is not limited only to the embodiment (specific example) described above, and includes various modifications. For example, in the embodiments described above, the entire system is explained in detail in order to explain the present invention in an easy-to-understand manner, and the system is not necessarily limited to having all the configurations described. Furthermore, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace some of the configurations of each embodiment with other configurations.

The light source device described above is not limited to a floating image display device, but can also be applied to display devices such as a HUD, a tablet, a digital signage, etc.

In the technology according to the present embodiment, by displaying a high-resolution and high-brightness video floating in space, the user can, for example, operate the video without feeling anxious about contact transmission of an infectious disease. enable. If the technology according to this embodiment is used in a system used by an unspecified number of users, it will be possible to reduce the risk of contact transmission of infectious diseases and provide a contactless user interface that can be used without anxiety. . According to the present invention, which provides such a technology, it contributes to "Health and well-being for all" of the Sustainable Development Goals (SDGs) proposed by the United Nations.

Further, in the technology according to the embodiment described above, by reducing the divergence angle of the emitted image light and aligning it with a specific polarization, only the regular reflected light can be efficiently reflected by the retroreflective member. , it is possible to obtain bright and clear spatial floating images with high light utilization efficiency. According to the technology according to the present embodiment, it is possible to provide a contactless user interface with excellent usability and which can significantly reduce power consumption. According to the present invention, which provides such technology, the Sustainable Development Goals (SDGs) advocated by the United Nations, ``9 Create a foundation for industry and technological innovation,'' and ``11 Create sustainable cities,'' can be achieved. Contribute to

Furthermore, the technology according to the embodiments described above makes it possible to form a spatially floating image using highly directional (straight-progressing) image light. With the technology according to this embodiment, even when displaying images that require high security such as at bank ATMs or ticket vending machines at stations, or when displaying highly confidential images that should be kept secret from the person directly facing the user, the technology can be used to display highly directional images. By displaying the image light, it is possible to provide a non-contact user interface in which there is little risk that the floating image will be looked into by anyone other than the user. By providing the above-mentioned technology, the present invention contributes to the Sustainable Development Goals (SDGs: Sustainable Development Goals 11) advocated by the United Nations.

DESCRIPTION OF SYMBOLS 1... Image display device, 2... First retroreflective member, 5... Second retroreflective member, 3... Spatial image (spatial floating image), 100... Transmissive plate, 13... Light source device, 54... Light direction conversion Panel, 105... Linear Fresnel sheet, 101... Absorption type polarizing sheet (absorption type polarizing plate), 200... Flat 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, 306... Reflective light guide, 307... Reflective surface, 308, 310... Sub-reflector, 204... Space floating image , 334... Image light control sheet, 336... Transmissive section, 337... Light absorbing section, 81... Optical element, 501... Polarization conversion element, 503... Unit, 507... Light blocking wall, 401, 402... Light blocking plate, 320... Base material , 511... Housing, 512... Support arm, 513... Hinge, 514... Back cover, 515... Housing cover, 516... Housing base, 517, 518... Inclined linear Fresnel sheet, 519... Eccentric Fresnel sheet.

Claims (12)

A spatial floating image display system,
a display panel that displays images;
a light source device that supplies light to the display panel;
a retroreflective member that reflects image light from the display panel and displays a real spatial floating image in the air using the reflected light;
The retroreflective member has a first reflective part and a second reflective part,
The angle formed by the spatial floating image floating in the center and the spatial floating image formed at a specific angle and distance based on the spatial floating image floating in the center is the angle formed by the first reflecting part and the second reflecting part. Adjusted by the intersection angle with the reflective part,
Space floating video display system. The spatial floating image display system according to claim 1,
The emission direction and divergence angle of the image light beam of each of the three spatially floating images obtained by the retroreflection member are adjusted by the diffusion characteristics of the display panel and the light source of the light source device.
Space floating video display system. The spatial floating image display system according to claim 1,
Three of the spatially floating images are displayed, and the image displayed on the display panel is adjusted so that the brightness of the peripheral areas of the three spatially floating images is lower than that of the center.
Space floating video display system. The spatial floating image display system according to claim 1,
The brightness of the spatial floating image floating in the center is the lowest compared to other spatial floating images.
Space floating video display system. The spatial floating image display system according to claim 1,
The brightness of the space floating image floating in the center is about 50% of the brightness of the other space floating images.
Space floating video display system. The spatial floating image display system according to claim 1,
The light source device includes:
A point or planar light source,
a reflector that reflects light from the light source;
a light guide that guides light from the reflector toward the display panel;
The reflective surface of the reflector has an asymmetric shape with respect to the optical axis of the light emitted from the light source.
Space floating video display system. The spatial floating image display system according to claim 6,
The light guide is a reflective light guide.
Space floating video display system. The spatial floating image display system according to claim 6,
a diffusion plate that diffuses light from the light guide;
side walls arranged to sandwich a space between the light guide and the diffuser plate;
Space floating video display system. The spatial floating image display system according to claim 6,
The reflector is made of plastic material, glass material or metal material,
Space floating video display system. The spatial floating image display system according to claim 1,
The first light control panel having the first reflective part and the second light control panel having the second reflective part are arranged one above the other,
Space floating video display system. The spatial floating image display system according to claim 1,
A first light control panel having the first reflective part and a second light control panel having the second reflective part are arranged one above the other,
The first reflecting section and the second reflecting section are arranged to intersect at right angles in a plan view,
Space floating video display system. a display panel that displays images;
a light source device for the display panel;
A spatial floating image processing system comprising: a retroreflective member that reflects image light from the display panel and displays a real spatial floating image in the air using the reflected light,
adjusting the emission direction and divergence angle of the image luminous flux of each of the three spatially floating images obtained by the retroreflective member according to the diffusion characteristics of the display panel and the light source of the light source device;
emphasizing a brightness gradient in accordance with the direction of light and the intensity of reflection on the light irradiation surface in accordance with the image displayed on the display panel;
Space floating image processing system.

Images