Space-floating image display device

Abstract

To provide a technique which achieves thinning of a system or a space floating picture display device and reduction of influence of heat on a light source device.SOLUTION: A space floating picture display device includes: a light source device; a display panel for emitting light from the light source device as picture light; and a retroreflective member for reflecting the picture light from the display panel and forming a space floating picture as a real image in the air by the reflected light. The light source device includes a light source, a reflector for reflecting light from the light source, and a light guiding member for guiding light from the reflector to the display panel. The light guiding member has the nearest part with a recessed part.SELECTED DRAWING: Figure 26A

Description

[Technical Field]

[0001] The present invention relates to a technology for a space floating image display device. [Background technology]

[0002] As a space-floating image display system, an image display device that displays an image directly to the outside and a display method that displays it as a spatial screen are already known. Also, a detection system that detects operations on the operation surface of the displayed spatial image is already known.

[0003] A conventional example of a spatially floating image display system is a configuration example that combines an image display device including an image display element such as a liquid crystal panel with a retroreflective member that generates a spatially floating image. The retroreflective member is sometimes referred to as a retroreflector or retroreflective sheet. In this configuration example, the image light from the image display device is retroreflected by the retroreflective member, and a spatially floating image is formed at a position symmetrical to the image display device using the retroreflective member as a reference. Such a retroreflective optical system is disclosed, for example, in Patent Document 1. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-142577 Summary of the Invention [Problem to be solved by the invention]

[0005] In the case of the above-described example of a space-floating image display device having a retroreflective optical system, conventionally, insufficient consideration has been given to making the space-floating image display system thin, i.e., minimizing the depth dimension during implementation. Depending on the system implementation, the space-floating image display device needs to arrange components such as a light source device, a liquid crystal panel, and a retroreflector within the system housing, as well as a flexible printed circuit board for driving the liquid crystal panel, in other words, a flexible cable, and electronic circuit boards such as a relay board. It is required to arrange the components compactly within the system housing.

[0006] Furthermore, in the case of the above configuration example, conventionally, a light source device serving as a backlight source for a liquid crystal panel is required to have a sufficiently high brightness (luminance) of the liquid crystal panel and to have uniform luminance throughout the screen (uniformity of luminance). However, there has been insufficient consideration given to achieving both a slim system and the uniformity of luminance.

[0007] Conventional floating image display devices have room for improvement in terms of system optimization in order to achieve both a thinner system and uniform brightness on the liquid crystal panel screen.

[0008] An object of the present disclosure is to provide a technology relating to a space-floating image display device that achieves both a thin system and a space-floating image display device and uniform brightness on a liquid crystal panel screen. [Means for solving the problem]

[0009] To solve the above problems, for example, the configuration described in the claims is adopted. The present application includes multiple means for solving the above problems, but the following provides an example of a space-floating image display device. The space-floating image display device displays a space-floating image, and includes a light source device, a display panel that emits light from the light source device as image light, and a retroreflective member that reflects the image light from the display panel and forms a space-floating image that is a real image in the air with the reflected light. The light source device includes a light source, a reflector that reflects the light from the light source, and a light guide that guides the light from the reflector toward the display panel, and the light guide includes a nearest portion having a recess. [Effects of the Invention]

[0010] According to a representative embodiment of the present disclosure, in relation to the technology related to the space-floating image display device, it is possible to realize a thin system and a space-floating image display device, and to improve the uniformity of the brightness on the liquid crystal panel screen. Problems, configurations, effects, etc. other than those described above will be described in the description of the embodiment of the invention. [Brief explanation of the drawings]

[0011] [Figure 1A] 1A and 1B are diagrams illustrating an example of the configuration of a retroreflective member according to an embodiment. [Figure 1B] 10A and 10B are diagrams illustrating positions where a floating image is generated in a retroreflective optical system including a retroreflective member according to an embodiment. [Figure 2A] 1 is a perspective view of a retroreflective member according to an embodiment of the present invention, illustrating the mechanism by which specular reflected light and extraordinary reflected light are generated. FIG. [Figure 2B] FIG. 2 is a plan view of a retroreflective member according to an embodiment of the present invention, illustrating the mechanism by which specular reflection light and extraordinary reflection light are generated. [Figure 3A] 1 is an explanatory diagram of a mechanism for eliminating extraordinary light rays that occur when external light is incident on a retroreflective member according to an embodiment. FIG. [Figure 3B]1 is an explanatory diagram of a mechanism for eliminating extraordinary light rays that occur when external light is incident on a retroreflective member according to an embodiment. FIG. [Figure 4A] 1 is a diagram illustrating an example of the configuration of a video display device according to an embodiment; [Figure 4B] 1A and 1B are diagrams illustrating an example of the configuration of a retroreflective member according to an embodiment. [Figure 5A] 1 is a diagram illustrating a design example of a system including a space floating image display device according to an embodiment. [Figure 5B] 1 is a diagram illustrating a design example of a system including a space floating image display device according to an embodiment. [Figure 6] FIG. 1 is a diagram illustrating an example of the configuration of an aerial sensor that constitutes a space floating image display device according to an embodiment. [Figure 7A] 1 is a schematic cross-sectional view showing an example of the configuration of a liquid crystal panel, a flexible cable, a substrate, etc. that constitute a space floating image display device according to one embodiment. [Figure 7B] 1 is a schematic plan view showing an example of the configuration of a liquid crystal panel, a flexible cable, a substrate, and the like that constitute a space floating image display device according to an embodiment. FIG. [Figure 8] 10A and 10B are diagrams illustrating an example of a configuration for routing a flexible cable or the like of a video display device as a comparative example. [Figure 9] 1 is a diagram showing an example of the configuration of the flexible cable and the like of the image display device in a space floating image display device according to an embodiment; [Figure 10] 1 is a perspective view showing an outline of the configuration of a space floating image display device according to a first embodiment. [Figure 11] 1 is a vertical cross-sectional view showing an outline of the configuration of a space floating image display device according to a first embodiment. [Figure 12] FIG. 1 is a perspective view showing a configuration of the space floating image display device of the first embodiment with a cover. [Figure 13] FIG. 1 is a perspective view showing the configuration of the space floating image display device of the first embodiment without a cover. [Figure 14] 1 is a plan view showing a configuration of the space floating image display device of the first embodiment with a cover. FIG. [Figure 15]1 is a plan view showing the configuration of the space floating image display device of the first embodiment without a cover. [Figure 16] 1 is a side view showing the configuration of the space floating image display device of the first embodiment with a cover. FIG. [Figure 17] 1 is a vertical cross-sectional view showing a configuration of a space floating image display device according to a first embodiment. [Figure 18] 1 is a perspective view showing a configuration of a light source unit and the like on the lower side of the image display device in the space floating image display device according to the first embodiment. FIG. [Figure 19] 1 is a perspective view showing a configuration of a light source unit and the like on the upper side of the image display device in the space floating image display device according to the first embodiment. FIG. [Figure 20] FIG. 1 is a perspective view showing an example of the configuration of a conventional kiosk terminal. [Figure 21] 1 is a perspective view showing a first configuration example of a kiosk terminal as a space-floating image display system including the space-floating image display device of the first embodiment. FIG. [Figure 22] 1 is a longitudinal sectional view of a first configuration example of a kiosk terminal. [Figure 23] FIG. 10 is a perspective view showing a second configuration example of a kiosk terminal as a space-floating image display system including the space-floating image display device of the first embodiment. [Figure 24] FIG. 10 is a longitudinal sectional view of a second configuration example of a kiosk terminal. [Figure 25A] 1 is a structural diagram showing a specific example of the configuration of a light source device according to an embodiment; [Figure 25B] 1 is a perspective view showing an example of the configuration of a light source unit in a specific example of the configuration of a light source device according to an embodiment; [Figure 25C] 3 is a cross-sectional view of a part of a light source section and a light guide section in a specific configuration example of a light source device according to an embodiment. FIG. [Figure 25D] 10A and 10B are diagrams illustrating a reflective surface of a light guide of a light guide portion in a specific configuration example of a light source device according to an embodiment. [Figure 25E] 3 is a cross-sectional view of a part of a light source section and a light guide section in a specific configuration example of a light source device according to an embodiment. FIG. [Figure 25F]3 is a cross-sectional view of an LED, a reflector, a light-shielding plate, and the like in a specific configuration example of a light source device according to an embodiment. [Figure 25G] 3 is a cross-sectional view of an LED, a light-shielding plate, and the like in a specific configuration example of a light source device according to an embodiment. [Figure 26A] 3 is a cross-sectional view of a part of a light source section and a light guide section in a specific configuration example of a light source device according to an embodiment. FIG. [Figure 26B] 3 is a cross-sectional view of a part of a light source section and a light guide section in a specific configuration example of a light source device according to an embodiment. FIG. [Figure 26C] 10A and 10B are diagrams illustrating non-uniformity of screen luminance caused by a light source device according to an embodiment. [Figure 26D] 3 is a cross-sectional view of a part of a light source section and a light guide section in a specific configuration example of a light source device according to an embodiment. FIG. [Figure 26E] 3 is a cross-sectional view of a part of a light source section and a light guide section in a specific configuration example of a light source device according to an embodiment. FIG. [Figure 26F] 1 is a perspective view of a part of a light source unit and a light guide unit in a specific configuration example of a light source device according to an embodiment. [Figure 26G] 3 is a cross-sectional view of a part of a light source section and a light guide section in a specific configuration example of a light source device according to an embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] 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 contents of the embodiments (also referred to as "the present disclosure" or "examples") described below. The present invention also extends to the spirit of the invention and the scope of the technical ideas described in the claims, or equivalents thereof. Furthermore, the configurations of the embodiments described below are merely examples, and various changes and modifications are possible by those skilled in the art within the scope of the technical ideas disclosed in this specification.

[0013] Furthermore, in the drawings for explaining the present invention, components having the same or similar functions are given the same reference numerals, and different names are used as appropriate, while repeated explanations of functions, etc. may be omitted. In the following description of the embodiments, an image floating in space is expressed using the term "space-floating image." Instead of this term, it is also acceptable to express it as "aerial image," "spatial image," "floating image," "space-floating optical image of displayed image," "floating optical image of displayed image," etc. The term "space-floating image," which is mainly used in the description of the embodiments, is used as a representative example of these terms.

[0014] The present disclosure relates to a display system that can display an image generated by image light from a large-area image light source as a floating image inside or outside a store space by transmitting the image through a transparent member that divides the space, such as the glass of a shop window. The present disclosure also relates to a large-scale digital signage system that is configured using multiple such display systems.

[0015] According to the following embodiment, for example, it is possible to display a high-resolution image floating in space on the glass surface of a shop window or a light-transmitting plate. In this case, by making the divergence angle of the emitted image light small, i.e., an acute angle, and further aligning it with a specific polarization, it is possible to efficiently reflect only the normal reflected light from the retroreflective material. This results in high light utilization efficiency, and it is possible to suppress the ghost image that occurs in addition to the main floating image in space, which was a problem with conventional retroreflective methods, and to obtain a clear floating image in space.

[0016] Furthermore, a device including the light source of the present disclosure can provide a novel and highly usable floating image display system that can significantly reduce power consumption. Furthermore, the technology of the present disclosure can provide a floating image display system for a vehicle that can display a so-called unidirectional floating image that can be seen from outside the vehicle through shield glass such as the vehicle's windshield, rear glass, or side glass.

[0017] As shown in FIG. 1A, the retroreflective member 5 used in the space-floating image display device is configured with a first light control panel 221 (also referred to as the first light control member) and a second light control panel 222 (also referred to as the second light control member). The first light control panel 221 and the second light control panel 222 are each formed by arranging optical members 20, each having a large number of strip-shaped planar light-reflecting portions, at a constant pitch, perpendicularly on one side of transparent flat plates 18 and 17 with a constant thickness. The optical members 20 are light-reflecting members. Here, the light-reflecting portions of the optical members 20 constituting the first light control panel 221 and the second light control panel 222 intersect in a planar view of the main surface of the retroreflective member 5, and are arranged orthogonal in this embodiment.

[0018] Next, the function of the retroreflective member 5 used in the space-floating image display device and specific examples of the space-floating image display device will be described. As shown in FIG. 1B, the retroreflective member 5 is generally disposed at an angle θ2 of 40 to 50 degrees relative to the image display device 1. The space-floating image 3 is emitted from the retroreflective member 5 at the same angle (90 degrees - θ2) as the angle at which the image light enters the retroreflective member 5. The space-floating image 3 is disposed at an angle θ1 relative to the retroreflective member 5. The space-floating image 3 is formed symmetrically with respect to the retroreflective member 5, a distance equal to the distance L1 from the image display device 1 to the retroreflective member 5.

[0019] The imaging mechanism of the spatial floating image 3 will be described in detail below with reference to FIGS. 1A to 2B. FIG. 2A is a perspective view of the retroreflective member 5 of FIG. 1A. FIG. 2B shows the configuration of the main surface of the retroreflective member 5 in a plan view. FIG. 2A shows how image light from the image display device 1 enters the retroreflective member 5 from the transparent flat plate 18 as one side, is reflected by the light reflecting portions of the optical members 20 of the first light control panel 221 and the second light control panel 222, and exits the transparent flat plate 17 as the other side. In the plan view of FIG. 2B, the intersections of the optical members 20 of the first light control panel 221 and the second light control panel 222 form a lattice-like light reflecting portion.

[0020] Image light emitted from the image display device 1 provided on one side of the retroreflective member 5 in FIG. 1B is reflected by the planar light reflecting portion C of the second light control member 222 in FIG. 2A, and then reflected by the planar light reflecting portion C' of the first light control member 221. As a result, as shown in FIG. 1B, a real image, which is a space-floating image 3, is formed in the space on the other side of the space on the image display device 1 side, at a position outside the retroreflective member 5. The planar light reflecting portion C and the planar light reflecting portion C' are reflective surfaces of the light reflecting member 20. By using this retroreflective member 5, a space-floating image display device is established, and the image of the image display device 1 can be displayed in space as a space-floating image 3.

[0021] As described above, the retroreflective member 5 has two reflecting surfaces, and therefore, in addition to the space-floating image 3 generated by the regular reflected light, two ghost images 3a and 3b are generated according to the number of reflecting surfaces, as shown in Figures 2A and 2B. The reflected light emitted from the retroreflective member 5 includes regular reflected light that forms the regular image of the space-floating image 3, and abnormal reflected light that forms the ghost images 3a and 3b.

[0022] Furthermore, when the intensity of external light is high and it enters from the top surface of the retroreflective member 5, the spacing between the reflective surfaces becomes short (for example, 300 μm or less), which can cause optical interference, resulting in the observation of rainbow-colored reflected light and the viewer's awareness of the presence of the retroreflective member 5. Therefore, to prevent the interference light generated by the pitch of the reflective surfaces of the retroreflective member 5 due to the incidence of external light from returning to the viewer's eyes, we experimentally determined the area where interference light occurs using the angle of incidence of external light as a parameter in the measurement environment shown in FIG. 3A. The results obtained are shown in FIG. 3B. It was found that when the pitch of the reflective surfaces is 300 μm and the height of the reflective surfaces is 300 μm, the interference light does not return to the viewer's side when the retroreflective member 5 is tilted at an inclination angle θYZ of 35 degrees or more.

[0023] On the other hand, it was found that when the ratio H / P of the pitch P of the light-reflecting member 20 to the height H of the reflective surface is set as described above, approximately 60% of the reflective surface forms a floating image due to retroreflection, while the remaining 40% becomes abnormally reflected light that generates ghost images. To improve the resolution of floating images in the future, it will be necessary to shorten the pitch of the reflective surface. Additionally, to suppress the generation of ghost images, the height of the reflective surface must be increased. Due to manufacturing constraints on the retroreflective member 5, it is recommended that the ratio H / P of the pitch P of the reflective surface to the height H be set in the range of 0.8 to 1.2, compared to the current value of 1.0.

[0024] As a result of the above-mentioned investigation, the inventor has investigated a retroreflective optical system that realizes high quality of the space floating image obtained in a space floating image display system using a retroreflective member that theoretically generates a small amount of ghost images. The details will be explained below with reference to the drawings.

[0025] <Configuration example of first retroreflective optical system> 4A and 4B show an example of the configuration of the image display device 1 and the retroreflective member 5 that constitute the first retroreflective optical system used to realize the space floating image display system. In the following description of the embodiment, the liquid crystal panel 11 is referred to as the "liquid crystal panel," but it may also be referred to as the "liquid crystal display panel," "display panel," "image display element," etc. instead of this term.

[0026] 1B, the space-floating image 3 is formed at a symmetrical position to the image display device 1 with respect to the retroreflective member 5. Therefore, the angles θ1 and θ2 formed by each arrangement are approximately equal. Therefore, when the angle at which the viewer's eyes look into the space-floating image 3 of the space-floating image display system is determined, it is advisable to set the angle θ2 between the image display device 1 and the retroreflective member 5 in the retroreflective optical system to, for example, 1 / 2 of the angle at which the viewer's eyes look into the space-floating image 3.

[0027] Furthermore, a certain distance L1 or more is required between the image display device 1 and the retroreflective member 5 in order to improve the cooling efficiency of the image display device 1. Furthermore, in order to structurally obtain the angle θ2, it is necessary to determine the distance L2 relative to the distance L1.

[0028] The space-floating image display device of the embodiment includes an image display device 1 that diverges image light of a specific polarization at a narrow angle, and a retroreflective member 5 that retroreflects the image light diverging at a narrow angle from the image display device 1. A space-floating image 3 having directionality in a specific direction is formed by the retroreflected light from the retroreflective member 5. As shown in FIG. 4A etc., the image display device 1 includes a liquid crystal panel 11 and a light source device 13 that generates light of a specific polarization with narrow-angle diffusion characteristics as a backlight for the liquid crystal panel 11.

[0029] Furthermore, an absorptive polarizing sheet with an anti-reflection film may be provided on the outer surface of the retroreflective member 5 facing the space floating image 3. The absorptive polarizing sheet selectively transmits image light of a specific polarized wave for forming the space floating image 3, while absorbing the other polarized wave contained in external light. This prevents the influence of light reflected by the surface of the retroreflective member 5 on the space floating image 3.

[0030] The light that forms 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 in a straight line even after passing through the optical image of the floating image 3. Therefore, the floating image 3 is an image with high directionality, unlike the diffused image light formed on a screen by a general projector or the like.

[0031] 1B, when viewed from the viewer's eyes, the floating image 3 is perceived as a bright image, but when viewed from another direction, for example, the opposite direction from the viewer's eyes, the floating image 3 cannot be seen at all. This characteristic is very suitable for use in systems that display images that require high security or highly confidential images that should be kept secret from people facing the user.

[0032] Depending on the performance of the retroreflective member 5, the polarization axis of the image light after retroreflection may become misaligned. In this case, some of the image light with misaligned polarization axes is absorbed by the absorptive polarizing sheet described above. This prevents unnecessary reflected light from being generated in the retroreflective optical system, and prevents or suppresses degradation of the image quality of the floating image 3.

[0033] Furthermore, in the embodiment of the space-floating image display device, when a viewer looks into the space-floating image 3, the display screen of the image display device 1 itself is shaded by the reflective surface of the retroreflective member 5, so the image on the display screen of the image display device 1 itself is difficult to see, and the view of the space-floating image 3 is not obstructed.

[0034] The liquid crystal panel 11 in FIG. 4A can be applied to a small screen size of about 5 inches to a large screen size of over 80 inches, and is selected depending on the system implementation.

[0035] 2A and other figures, to obtain a high-quality space-floating image 3 by eliminating ghost images corresponding to abnormal reflected light, an image light control sheet may be provided on the exit surface side of the liquid crystal panel 11 to control the diffusion characteristics in unnecessary directions. Also, an image light control sheet may be provided on the image exit surface of the retroreflective member 5 to eliminate ghost images that appear on both sides of the normal image of the space-floating image 3.

[0036] For example, applying S-polarized light as the specific polarization to the image light from the liquid crystal panel 11 is preferable because, in principle, the reflectance at the retroreflective member 5 can be increased. S-polarized light is polarized perpendicular to the plane of incidence, while P-polarized light is polarized parallel to the plane of incidence. If the viewer wears polarized sunglasses, the light that forms the space-floating image 3 will be reflected or absorbed by the polarized sunglasses. To address this issue, a depolarizing element may be provided, which optically converts part of the specific polarized image light from the liquid crystal panel 11 into the other polarized light, thereby converting it into pseudo-natural light. In this case, the viewer can view a good space-floating image 3 even when wearing polarized sunglasses.

[0037] When an absorptive polarizing sheet is provided on the retroreflective member 5, or when an image light control sheet is provided on the liquid crystal panel 11 or the retroreflective member 5, if they are optically bonded using an adhesive, no light reflecting surface is generated and the image quality of the floating image 3 is not impaired.

[0038] <Technical means to reduce ghost images> Using FIG. 4A and other figures, we will explain technical means for realizing a high-quality spatial image display device with reduced ghost images. FIGS. 4A and 4B show specific technical means for applying an image light control sheet to a spatial image display device. As shown in FIG. 4A, in order to control the divergence angle of image light from a liquid crystal panel 11 serving as an image display element in a desired direction, an image light control sheet 334A may be provided on the exit surface of the liquid crystal panel 11. Furthermore, as shown in FIG. 4B, an image light control sheet 334B may be provided on the light exit surface or light entrance surface or both of the retroreflective member 5 to absorb abnormal light that generates ghost images.

[0039] 4A is a vertical cross-sectional view of a configuration example in which an image light control sheet 334A is arranged on the image light output surface of a liquid crystal panel 11 of an image display device 1. The image light control sheet 334A is configured by alternately arranging light-transmitting portions 336 and light-absorbing portions 337, and is adhesively fixed to the image light output surface of the liquid crystal panel 11 by an adhesive layer 338.

[0040] 4B is a vertical cross-sectional view of an example configuration in which an image light control sheet 334B is arranged on the image light exit surface of the retroreflective member 5. The image light control sheet 334B is configured by arranging light transmitting portions 336 and light absorbing portions 337 alternately.

[0041] In FIG. 4A, the following two methods are effective for reducing moire generated by interference according to the pitch between the pixels of the liquid crystal panel 11 and the transmissive portions 336 and light absorbing portions 337 of the image light control sheet 334A.

[0042] In the first method, the vertical stripes formed by the light transmitting portions 336 and the light absorbing portions 337 of the image light control sheet 334A are arranged so as to be tilted at a predetermined angle with respect to the arrangement of the pixels of the liquid crystal panel 11.

[0043] In the second method, when the pixel size of the liquid crystal panel 11 is A and the pitch of the vertical stripes of the image light control sheet 334A is B, the ratio B / A is selected as a value that is not an integer multiple.

[0044] Each pixel of the liquid crystal panel 11 is made up of three sub-pixels of RGB arranged in parallel, and is generally square, so it is not possible to suppress the occurrence of the above-mentioned moire across the entire screen. For this reason, as a result of experimental results, the tilt angle shown in the first method should be optimized within a range of, for example, 5 to 25 degrees so that the position where the moire occurs can be intentionally shifted to a location where the floating image 3 is not displayed.

[0045] While the reduction of moiré has been discussed using the liquid crystal panel 11 as an example, the moiré occurring between the retroreflective member 5 and the image light control sheet 334B in FIG. 4B can be reduced as follows. Because both the retroreflective member 5 and the image light control sheet 334B are linear structures, the image light control sheet 334B is optimally tilted with respect to the X-axis. In FIG. 4B, the vertical stripes of the transmissive portions 336 and the light-absorbing portions 337 of the image light control sheet 334B are tilted at an angle θX relative to the surface normal to align with the direction of retroreflected light emission. This reduces large moiré patterns with long wavelengths and low frequencies that are visible to the naked eye. This also absorbs the extraordinary light generated by the retroreflection described above while transmitting regular reflected light without loss.

[0046] Furthermore, when a 7-inch WUXGA (1920 × 1200 pixel) liquid crystal panel, for example, is used as the liquid crystal panel 11 serving as the image display element, the following transmission characteristics can be achieved. In this case, even if the pitch A of one pixel (one triplet) is approximately 80 μm, sufficient transmission characteristics can be achieved if, for example, the width d2 of the transmissive portion 336 of the image light control sheet 334A in FIG. 4A is 300 μm, the width d1 of the light-absorbing portion 337 is 40 μm, and the pitch B is 340 μm. In this case, the diffusion characteristics of the image light from the image display device 1, which causes abnormal light, can be controlled, and ghost images that appear on both sides of the normal image of the spatial floating image 3 can be reduced. In this case, if the thickness of the image light control sheet 334A is at least two-thirds of the pitch B, the ghost reduction effect is significantly improved.

[0047] On the other hand, the image light control sheets 334A and 334B described above also prevent external light from entering the interior of the spatial floating image display device, thereby improving the reliability of the components. For example, a viewing angle control film (VCF) from Shin-Etsu Polymer Co., Ltd. is suitable as an image light control sheet. The VCF has a sandwich structure in which transparent silicon and black silicon are alternately arranged, with synthetic resin placed on the light entrance and exit surfaces. Therefore, VCF as an image light control sheet can be expected to have the same effect as an external light control film.

[0048] <System design> 5A and 5B are schematic explanatory diagrams of design considerations regarding the angles of arrangement of the space-floating image 3, retroreflective member 5, image display device 1, etc., in a space-floating image display system configured to include as an element the space-floating image display device employing the above-mentioned retroreflective optical system. FIG. 5A shows an example of arrangement assuming that the components of the space-floating image display device are housed or installed within the housing 501 of the space-floating image display system. Depending on the implementation example of the space-floating image display system, a suitable angle α that makes it easy to view the space-floating image 3 from the user's eye UE, the viewer, is assumed.

[0049] In the examples of Figures 5A and 5B, the angle α corresponds to the case where the floating image 3 is viewed from directly facing the plane perpendicular to the surface, and is angle α of about 45 degrees diagonally downward with respect to the Y direction corresponding to the horizontal line. Similarly, a suitable angle when operating the floating image 3 by touching it with the user's finger UH is assumed, and here this angle is also the same as angle α. An example of an implementation of the floating image display system in space will be described later, but one example is a so-called kiosk terminal. The kiosk terminal has a housing 501 of a predetermined shape.

[0050] The placement of the space-floating image 3 is determined according to the selection of the viewing angle α. In this case, the placement of the retroreflective member 5, image display device 1, and other components of the space-floating image display device are determined according to the placement of the space-floating image 3.

[0051] The example of FIG. 5A shows an example in which the retroreflective member 5 is positioned in line with the front surface 501a of the housing 501 so that the plane of the floating image 3 projects forward, or in other words, floats, relative to the front surface 501a of the housing 501, which is shown as a slope in the figure. The example of FIG. 5A also shows a case in which the upper and lower edges of the floating image 3 are positioned at an angle θ1, as shown, relative to the front surface 501a of the housing 501 and the retroreflective member 5, so that the protruding distance LA is greater on the upper edge side than on the lower edge side. The floating image 3 is positioned at an angle θ1 relative to the retroreflective member 5 and the front surface 501a of the housing 501. The liquid crystal panel 11 of the image display device 1 is positioned at an angle θ2 relative to the retroreflective member 5 and the front surface 501a of the housing 501.

[0052] On the other hand, the example of FIG. 5B shows a case where the upper and lower edges of the floating image 3 are arranged at the angle θ1 shown in the figure, so that the protruding distance LB is greater at the bottom edge than at the top edge relative to the front surface of the housing 501 and the retroreflective member 5. Distance LB is approximately the same as distance LA. The floating image 3 is arranged at an angle θ1 relative to the retroreflective member 5 and the front surface 501a of the housing 501. The liquid crystal panel 11 of the image display device 1 is arranged at an angle θ2 relative to the retroreflective member 5 and the front surface 501a of the housing 501. The angles θ1 and θ2 here are approximately the same or identical, and are smaller than the angles θ1 and θ2 of FIG. 1B described above, being less than 40 degrees.

[0053] 5A and 5B, the angles θ1 and θ2 are almost the same or identical, and both are smaller than the angles θ1 and θ2 in FIG. 1B, for example, smaller than 45 degrees. Also, in FIG. 5B, the distance between the bottom edge of the retroreflective member 5 and the bottom edge of the image display device 1 is approximately the same as the distance LB between the bottom edge of the retroreflective member 5 and the bottom edge of the floating image 3. The floating image 3 in FIG. 5B, which includes the angle α, is a suitable method when the height position of the viewer's eyes UE, which are assumed as a reference, is relatively high.

[0054] The space-floating image display device has a cover 502 that houses the components such as the image display device 1 and the retroreflective member 5, and is illustrated in a dashed frame in Figures 5A and 5B. The space-floating image display device including the cover 502 is preferably housed in a system housing 501. The image display device 1 and the retroreflective member 5 are fixed in a predetermined positional relationship within the cover 502, as illustrated.

[0055] The image display device 1 is configured to have a liquid crystal panel 11 and a light source assembly 30 which is a light source device 13. The light source assembly 30 is configured to have an LED which is a light source described below, a reflector, a polarization conversion element, a light guide, a diffusion plate, etc. The liquid crystal panel 11 is fixed to the light source assembly 30.

[0056] The space-floating image display device also has an aerial sensor 50 that can detect operations by an object such as the user's finger UH on the surface of the space-floating image 3. In the example of Fig. 5A, the aerial sensor 50 is provided at the bottom of the front surface 501a of the housing 501, corresponding to the bottom side of the space-floating image 3. In the example of Fig. 5B, the aerial sensor 50 is provided at the top of the front surface 501a of the housing 501, corresponding to the top side of the space-floating image 3. The aerial sensor 50 is not limited to being provided inside the cover 502, and may also be provided separately.

[0057] The aerial sensor 50 can also be positioned so that it protrudes forward from the front surface 501a of the housing 501, but in that case the cover 502, including the support member for the aerial sensor 50, would become large, so it is positioned at the front surface 501a as shown in the example.

[0058] Here, in the above-mentioned problem, making the system thinner means, for example, reducing the dimension of the housing 501 in the Y direction, which is the depth direction. Making the space-floating image display device thinner means, for example, reducing the dimension of the cover 502 in the Y direction, which is the depth direction. In response to the reduction in the thickness of the system, a compact configuration is required, including a small dimension of the cover 502 in the Y direction, so that the cover 502 of the space-floating image display device can be housed within the housing 501.

[0059] Furthermore, a flexible cable for driving, a relay board, a video signal processing board, etc. are connected to the liquid crystal panel 11. A power supply board is also required to supply power to the light source assembly 30, etc. These components are also desirably arranged so as to be housed within the cover 502 or the housing 501. This aspect will be discussed later.

[0060] For the sake of explanation, the method of the space-floating image 3 and the space-floating image display device shown in FIG. 5A will be referred to as the top-side protrusion method, and the method shown in FIG. 5B will also be referred to as the bottom-side protrusion method. In the embodiments described below, the method of FIG. 5B will be adopted for system optimization. When adopting the method of FIG. 5A, if a preferred angle α is prioritized, as shown in the figure, the depth dimension will be large due to the layout and shape of the housing 501 and cover 502. Furthermore, in the method of FIG. 5A, if the angle of the front surface 501a of the housing 501, which is the slope, is desired to be closer to vertical as shown in FIG. 5B, the angle of the layout of the space-floating image 3 will also be closer to vertical. Therefore, in this case, it may be difficult to see or operate.

[0061] In contrast, in the case of the method of Fig. 5B, the dimensions in the depth direction can be made smaller in the arrangement and shape of the housing 501 and cover 502 than in the case of Fig. 5A. In the case of Fig. 5B, the advantages are obtained such as thinning of the system and device, optimization of the system taking into consideration the reduction of the thermal influence of the light source assembly 30, ease of viewing and operation of the floating image 3 in space, and ease of system implementation.

[0062] In one embodiment, a space-floating image display system is configured, for example, by incorporating a space-floating image display device such as that shown in FIG. 5B above, on top of a kiosk terminal. As described above, the positions and angles of the retroreflective member 5 of the space-floating image display device and the image display device 1 are optimally designed so that the space-floating image 3 can be optimally viewed in a direction corresponding to the desired angle α from the expected position of the viewer's eyes UE. The space-floating image 3 displayed by the space-floating image display device on top of this kiosk terminal displays an image such as an avatar guiding the user through services. In this case, the image light of the space-floating image 3 is directed toward the viewer's eyes at a suitable angle α, allowing the viewer to view the high-brightness space-floating image 3 at the suitable angle α. The viewer can also operate the space-floating image 3 at the suitable angle α.

[0063] <Airborne sensor> Aerial sensor 50 will be described as a sensing technology that allows a viewer to operate the space-floating image 3 produced by the space-floating image display device as an operator. For example, an example configuration of aerial sensor 50 that can be applied to the configuration of FIG. 5B will be described. On the plane on which the space-floating image 3 is arranged, aerial sensor 50 is placed at a position away from the top side of the space-floating image 3. More specifically, aerial sensor 50 may be placed so as to be hidden behind a member that constitutes front surface 501a of housing 501.

[0064] The aerial sensor 50 is configured with a sensor device and a detection circuit. The aerial sensor 50 can be implemented using, for example, a distance measuring device with an AirBar (registered trademark) built in. Figure 6 shows an example of the configuration of the aerial sensor 50, and shows the configuration in the xy plane as the plane on which the floating image 3 is arranged.

[0065] The aerial sensor 50 has, for example, a light-emitting unit 50a and a light-receiving unit 50b as sensor devices, arranged alternately along the x direction on a long, plate-shaped substrate 50A, for each row corresponding to the lines in the y direction of the floating image 3. The light-emitting unit 50a uses, for example, a near-infrared emitting LED as a light source. The light-emitting unit 50a emits near-infrared light downward in the y direction in synchronization with a system signal. An optical element (not shown) for controlling the divergence angle is arranged on the output side of the LED of the light-emitting unit 50a.

[0066] The light receiving unit 50b, which is paired with the light emitting unit 50a, receives light reflected upward in the y direction. The aerial sensor 50 can detect the position of a finger UH or an object such as a pen when an operation such as a touch is performed in the air on the surface of the floating image 3, based on the intensity of infrared light detected by the light receiving unit 50b when the light from the light emitting unit 50a is reflected by, for example, the fingertip of the finger UH.

[0067] When a finger UH is positioned at a certain pixel position GP on the xy plane of the floating image 3 by an operation such as touching, light from the light-emitting unit 50a is reflected at that pixel position GP, ​​and the reflected light is received by the light-receiving unit 50b. Based on the detection signals from these multiple sensor devices, the detection circuit of the aerial sensor 50 can detect the pixel position and movement when an operation such as a touch is performed in the air on the surface of the floating image 3 by the finger UH or an object such as a pen.

[0068] Furthermore, the aerial sensor 50 may also be provided in the z direction, which is the direction perpendicular to the xy plane of the floating image 3. In this case, it becomes possible to detect the position and movement of the fingers UH entering the plane of the floating image 3 in the z direction.

[0069] The sensor device of the aerial sensor 50 in FIG. 6 is placed at a predetermined distance from the upper side 3U of the floating image 3 on the xy plane.

[0070] 5B, the distance between the top side of the floating image 3 and the front surface 501a of the housing 501 is shorter than the protrusion distance LB on the bottom side, but this distance is still sufficiently secured. This prevents the user's fingers UH from coming into contact with the retroreflective member 5 during operation. Furthermore, the aerial sensor 50 is not limited to the above example, and a distance measuring device with a built-in TOF (Time Of Flight) system may also be used.

[0071] [LCD panel and light source assembly] 7A and 7B show configuration examples of the liquid crystal panel 11 and light source assembly 30 applied to the space-floating image display system and space-floating image display device, and are also schematic explanatory diagrams of the problem of the influence of heat from the light source assembly 30 on the flexible cable 703 of the liquid crystal panel 11. The problem will be explained using FIG. 7A and other figures. FIG. 7A illustrates a case where the liquid crystal panel 11 of the image display device 1 of the space-floating image display device is arranged in the horizontal direction in FIG. 7A. The horizontal direction in FIG. 7A is, for example, a horizontal plane, but is not limited thereto. FIG. 7B shows the flexible cable and each board connected to the main body of the liquid crystal panel 11 when the display screen 11a of the liquid crystal panel 11 is viewed in plan view.

[0072] Depending on the implementation of the space floating image display system, the size of the display screen 11a of the liquid crystal panel 11 is secured to a predetermined size. In this case, in the configuration example of FIG. 7A , in order to secure that size, the light source assembly 30 is composed of a light source assembly 30A and a light source assembly 30B. In the light source assembly 30, the light source assembly 30A and the light source assembly 30B are arranged as a pair symmetrically with respect to the center line C in the horizontal direction in FIG. 7A . The light source assembly 30A has a light source section 31A and a light guide section 32A. The light source section 31A includes a substrate, an LED, a reflector, a heat sink, etc., and the light guide section 32A includes a light guide, which will be described in detail below.

[0073] 7B, one end of a flexible cable 701 is connected to the main body of the liquid crystal panel 11, for example, on the side of the lower side 11D, and a relay board 702 is connected to the other end of the flexible cable 701. One end of a flexible cable 703 is connected to the other end of the relay board 702. A video signal processing board 704 is connected to the other end of the flexible cable 703. The spatial region in which the light source units 31A and 31B are arranged is illustrated by a dashed line frame. For example, the light source units 31A and 31B are arranged in an area above the upper side 11U and an area below the lower side 11D with respect to the area of ​​the display screen 11a of the liquid crystal panel 11. Power is supplied to these light source units 31A and 31B from a power supply board (not shown).

[0074] Such light source assembly 30, flexible cable 703, each board, etc. are housed in cover 502 as shown in Fig. 5B. In Fig. 5B, upper space 5001 in housing 501 is narrower than lower space 5002, so it is disadvantageous to place flexible cables, etc. in upper space 5001. Therefore, in this embodiment, it is considered to place and house flexible cable 703, etc., drawn out from the lower side 11D of liquid crystal panel 11, in lower space 5002 in housing 501 in Fig. 5B.

[0075] In lower space 5002 within housing 501, the space available for storage, including the depth dimension, is also limited, and it is necessary to keep the volume of cover 502 as small as possible. If flexible cable 703 and the like are arranged with a large margin within lower space 5002, cover 502 becomes large and it becomes difficult to store it within housing 501. For this reason, flexible cable 703, relay board 702, and the like are stored compactly within cover 502, the volume of which is kept to a minimum in accordance with the dimensions of housing 501, including the depth dimension.

[0076] However, when the light source assembly 30, flexible cable 703, etc. are housed inside the cover 502 with a reduced volume, the flexible cable 703, relay board 702, etc. must be arranged in close contact with or close to the light source assembly 30.

[0077] FIG. 8 shows a comparative example in which a flexible cable 703, a board, and the like are arranged inside the cover 502 adjacent to the light source unit 31 of the light source assembly 30, prioritizing a compact configuration that minimizes the thickness of the cover 502. FIG. 8 illustrates a portion corresponding to only one light source assembly 30A. Because the space between the liquid crystal panel 11 and the retroreflective member 5 forms the optical path of the image light, a flexible cable and the like are not arranged on that side. In this comparative example, the flexible cable 703 and the like are arranged so as to wrap around the back side of the light source assembly 30A via the side of the light source unit 31A. In this comparative example, in the direction shown in FIG. 8, the flexible cable 701 and the relay board 702 are arranged above the light source unit 31A, the flexible cable 702 is arranged adjacent to the left side of the light source unit 31A, and the video signal processing board 704 is arranged adjacent to the lower side of the light source unit 31A. The cover 502 is configured to accommodate these components.

[0078] However, in the case of such a comparative example, components such as flexible cable 703, which are vulnerable to heat, are arranged close to light source unit 31A, and therefore these components are susceptible to the effects of heat emitted from the light source, reflector, and heat sink of light source unit 31A, which may result in deterioration or damage to flexible cable 703, etc.

[0079] Furthermore, as shown in FIG. 8, when the liquid crystal panel 11 and the light source assembly 30A are arranged on a horizontal plane, for example, the heat from the light source unit 31A flows vertically from bottom to top, thermodynamically, and therefore the flexible cable 703 and the relay board 702 are easily affected by the heat.

[0080] Therefore, in this embodiment, the light source assembly 30, flexible cable 703, relay board 702, etc. are housed in cover 502 with reduced volume, and a configuration is devised that takes into consideration both a compact configuration and a reduction in the influence of heat from the light source unit. Details are described below.

[0081] <Space-floating image display device according to the first embodiment> Fig. 9 shows an outline of the configuration of the space-floating image display device of the first embodiment. In the space of housing 501 in the system of Fig. 5B, image display device 1 is arranged along the Z-axis direction corresponding to the vertical direction. In lower space 5002, flexible cable 701 drawn out from the lower side of liquid crystal panel 11, relay board 702, flexible cable 703, video signal processing board 704, etc. are arranged. In this embodiment, flexible cable 703 is arranged at a predetermined distance 1001 from light source unit 31A of light source assembly 30A. The components in Fig. 9 are fixed in cover 502 in a predetermined positional relationship.

[0082] Flexible cable 703 is curved and arranged so as to wrap around from the relay board 702 side, which is arranged on the front side of light source unit 31A along the Y axis, via a lower part on the Z axis, to video signal processing board 704, which is arranged on the back side of light source unit 31A along the Y axis. Flexible cable 703 is arranged at a predetermined distance 1001 in the Z direction so as not to come close to light source unit 31A as it wraps around. Flexible cable 703 is arranged at a distance 1003 in the Y direction. Space 1002 is an enclosed space corresponding to distances 1001 and 1003.

[0083] This allows the dimensions of the system housing 501 and the device cover 502 to be kept small in the Y-axis direction, which is the depth direction. In the Z-axis direction, a distance 1001 is ensured by utilizing a space 5001 below the housing 501. The distance 1001 is designed depending on the implementation of the system or device, but is at least 1 cm or more. The distance 1001 is illustrated as the distance from the end face of the light source unit 31A, but in more detail, as will be described later, it may be the distance from the LED, which is the light source, or from any of the substrate, heat sink, and reflector.

[0084] In this embodiment, flexible cable 703 and other components that are susceptible to heat are positioned sufficiently far from light source unit 31A, so these components are less susceptible to the heat generated by the light source, reflector, and heat sink of light source unit 31A, and therefore deterioration and damage to flexible cable 703 and other components can be prevented.

[0085] Furthermore, when the liquid crystal panel 11 and the light source assembly 30A are arranged vertically as shown in FIG. 9, the heat from the light source unit 31A flows vertically from bottom to top thermodynamically, and therefore the flexible cable 703 arranged below the light source unit 31A is less susceptible to the effects of that heat.

[0086] 9 also shows an example of the placement of a power supply board 705 that supplies power to the light source unit 31A and the like. The power supply board 705 is placed on the rear side in the Y-axis direction relative to the light source assembly 30. The power supply board 705 also generates heat, but this heat flows upward in the vertical direction. The flexible cable 703, which is placed below the power supply board 705, is less affected by this heat.

[0087] Flexible cable 701 and relay board 702 are arranged on the front side in the Y-axis direction relative to light source unit 31A, but the light sources and other components in light source unit 31A are arranged closer to the rear side and the back in the Y-axis direction, and heat from the light sources and other components flows upward. Therefore, flexible cable 701 and relay board 702 are less susceptible to the heat from the light sources and other components in light source unit 31A.

[0088] The video signal processing board 704 is disposed on the rear side in the Y-axis direction relative to the light source unit 31A. The processors and other components on the video signal processing board 704 also generate heat, but heat sinks are also disposed on these processors, and the heat flows upward. Therefore, the video signal processing board 704 is less susceptible to the effects of heat from the light sources and other components in the light source unit 31A.

[0089] <Space-floating image display device according to the first embodiment> The details of the space-floating image display device of the first embodiment and the space-floating image display system including the space-floating image display device will be described below with reference to FIG. 10 and subsequent figures. Hereinafter, as an example of implementation of the space-floating image display system, a case where it is applied to a kiosk terminal installed in a station, a convenience store, etc. will be described. Note that the implementation example of the space-floating image display system is not limited to this, and it can be applied to various systems, for example, ATMs (automated teller machines), automatic ticket vending machines, etc. Depending on the system to which it is applied, there are requirements such as the shape of the housing 501, in other words, constraints, and a suitable viewing angle for the space-floating image 3. An example of an angle is the angle α in FIG. 5B described above. The space-floating image display device is implemented in the system according to these requirements.

[0090] 10 is a perspective view of the space floating image display device of the first embodiment, showing the portion excluding the above-mentioned cover 502 and light source assembly 30. The arrangement of the components in FIG. 10 is such that the liquid crystal panel 11 of the image display device 1 and the like are arranged along the Z-axis direction corresponding to the vertical direction, which corresponds to the arrangement of the system implementation as shown in FIG. 5B above.

[0091] 11 shows a cross-sectional view of the space floating image display device of the first embodiment in the YZ plane, and only shows a schematic outline of the aforementioned cover 502 and light source assembly 30. The vicinity of light source unit 31A and flexible cable 703 in FIG. 11 has the same configuration as FIG.

[0092] Video signal processing board 704 receives control signals from the system control device and video signals from the video source via a connector using a predetermined communication interface, and processes the video signals for displaying video on liquid crystal panel 11, which is a video display device. Video signal processing board 704 transmits display signals generated as a result of this processing from the connector to relay board 702 via flexible cable 703.

[0093] The relay board 702 receives a display signal from the video signal processing board 704, generates a drive signal for display driving of the liquid crystal panel 11 based on the display signal, and transmits the drive signal from the connector to the main body of the liquid crystal panel 11 via the flexible cable 701. The liquid crystal panel 11 is driven based on the drive signal to display an image on the display screen 11a.

[0094] The power supply board 705 is disposed on the rear side of the light source assembly 30, for example, near the center line C. The power supply board 705 supplies power to the light source unit 31 (31A, 31B) of the light source assembly 30 as shown in Fig. 7A. The power supply circuit of the power supply board 705 is connected to the board of the light source unit 31 via a power cable from a connector (not shown).

[0095] 12 is a perspective view of the floating-in-space image display device of FIG. 10 with cover 502, omitting the image display device 1 and other components. Examples of detailed configurations of cover 502 include covers 502a, 502b, and 502c. Cover 502a houses and secures the liquid crystal panel 11, light source assembly 30, flexible cable 703, and other components of image display device 1. Cover 502b secures retroreflective member 5, for example, at four sides. Cover 502c is a support member extending from cover 502a, and supports and secures airborne sensor 50.

[0096] FIG. 13 is a perspective view of the space floating image display device of FIG. 12 without the cover 502, showing the light source assembly 30, relay board 702, etc. of the image display device 1.

[0097] Fig. 14 shows an XY plan view of the space floating image display device of Fig. 12 with cover 502, viewed from the rear side in the Z-axis direction. Cover 502 has cover 502d that covers the rear side of light source assembly 30. Cover 502d also has a protrusion that serves as a portion for fixing video signal processing board 704.

[0098] 15 shows an XY plan view of the space floating image display device of FIG. 12 without cover 502, viewed from the rear side in the Z axis direction. On the rear side of light source assembly 30, below in the Z axis direction, is arranged video signal processing board 704. Video signal processing board 704 has a processor, a connector 704b for flexible cable 703, a heat sink 704c, etc. A power supply board 705 is arranged near the center of light source assembly 30 in the Z axis direction. In this example, three power supply boards 705 are provided, and are arranged in the X axis direction.

[0099] 16 shows a YZ plane view of the space floating image display device of FIG. 12 with cover 502, as seen from the X-axis direction, which is the side direction. In addition to the aforementioned parts, cover 502 has covers 502e and 502g. Cover 502e covers the part of image display device 1, including liquid crystal panel 11 and light source assembly 30, from both sides in the X-axis direction. Of cover 502e, cover 502f, which is the part located below in the Z-axis direction, covers the aforementioned flexible cable 703 and the like in the Z-axis direction and the X-axis direction.

[0100] In this embodiment, the cover 502 is configured so as not to cover the video signal processing board 704 and the power supply board 705. As a modified example, the cover 502 may be configured so as to cover the video signal processing board 704 and the power supply board 705 as well.

[0101] The cover 502g stands on the front side in the Y-axis direction from the cover 502e, and supports and fixes the retroreflective member 5.

[0102] FIG. 17 shows a YZ cross-sectional view of the space-floating image display device of FIG. 12 without cover 502, as viewed from the X-axis direction (side), and illustrates a detailed structural example corresponding to FIG. 11. Similar to FIG. 7A, the image display device 1 includes a pair of light source assemblies 30, a lower light source assembly 30A and an upper light source assembly 30B, which are arranged symmetrically in the Z-axis direction with respect to the center line C. For example, the lower light source assembly 30A includes a light source unit 31A arranged below the Z-axis and a light guide unit 32A arranged below the center line C and above the light source unit 31A. The light source assembly 30A emits light from the light source unit 31A upward along the Z-axis and reflects the light emitted by the light guide unit 32A forward along the Y-axis. The light source assembly 30B emits light from the light source unit 31B downward along the Z-axis and reflects the light emitted by the light guide unit 32B forward along the Y-axis. A diffusion plate 204 is disposed between the light guide portions 32A and 32B and the liquid crystal panel 11.

[0103] The light source unit 31A and the light source unit 31B extend longitudinally in the X-axis direction, and multiple light sources, reflectors, and the like are arranged in the X-axis direction. The light source unit 31A, which will be described in detail later, includes an LED as a light source in this example. A heat sink 330 is disposed behind the substrate on which the LED is mounted in the Y-axis direction. The heat sink 330 is an LED heat sink. The light source unit 31A reflects divergent light from the LED as nearly parallel light upward in the Z-axis direction using a reflector. The parallel light upward in the Z-axis direction is polarized and converted by a polarization conversion element (described later) before entering the light guide unit 32A. The incident light is reflected forward in the Y-axis direction by the reflective surface of the reflective light guide of the light guide unit 32A, diffused via the diffuser 204, and incident on the rear side of the liquid crystal panel 11. This same function is also observed in the light source assembly 30B, but in the opposite direction.

[0104] 17, the cover 502 is shown by a broken line, and details are as shown in Figures 12, 14, 16, etc. The cover 502 is made of a material such as metal.

[0105] As shown in Figure 17, the flexible cable 701, relay board 702, flexible cable 703, and video signal processing board 704 pulled out from the lower edge side of the liquid crystal panel 11 are arranged so as to detour around the light source unit 31A at a space 1002 including a distance 1001, and wrap around to the back side of the light source assembly 30A, as explained in Figure 9.

[0106] FIG. 18 is a perspective view of the light source unit 31A and flexible cable 703, etc., as viewed from the bottom side of the liquid crystal panel 11 and the back side of the light source assembly 30 of the image display device 1 of the space-floating image display device of FIG. 12. FIG. 19 is a perspective view of the light source unit 31B, etc., as viewed from the top side of the liquid crystal panel 11 and the back side of the light source assembly 30 of the image display device 1. The light source unit 31A and the light source unit 31B extend in the X-axis direction corresponding to the bottom and top sides of the liquid crystal panel 11, and a heat sink 330 is disposed at the back side along the Y-axis. In this example, the heat sink 330 is provided not only in a portion that contacts the back side of the LED substrate, but also in a portion facing outward along the Z-axis. As shown in FIGS. 7A and 10, the flexible cable 701, etc., is drawn out from the bottom side of the liquid crystal panel 11, for example, near the center in the X-axis direction. As shown in FIG. 18, the flexible cable 703 is disposed so as to wrap around one side of the light source unit 31A below the Z-axis.

[0107] 17, the space 1002 between the light source unit 31A and the flexible cable 703, etc., is basically configured so that nothing is provided other than air. As a modified example, a component for fixing the flexible cable 703, etc., at a predetermined suitable position may be provided in this space 1002. In this case, the component may be a part of the cover 502, for example, a component protruding from the cover 502f in FIG. 16.

[0108] According to the space-floating image display device of the first embodiment, it is possible to realize a thin and compact arrangement of the space-floating image display system and the space-floating image display device, and also to reduce the influence of heat on the light source assembly 30 and the like, thereby minimizing the influence of deterioration and the like on heat-sensitive parts such as the flexible cable 703.

[0109] 10 to 19 and the like, the space-floating image display device of the first embodiment can realize a compact configuration with the depth dimension minimized as described above, and can reduce the influence of heat from the light source unit 31A and the power supply board 705 on the heat-sensitive flexible cable 703 and the like. Furthermore, this space-floating image display device can be easily mounted on the housing 501 and the like of the space-floating image display system as shown in FIG. 5B, and realizes the user's preferable viewing and operation of the space-floating image 3.

[0110] In the above-described floating image display device of the first embodiment, flexible cables 703 and the like are routed from the liquid crystal panel 11 to the video signal processing board 704 by providing a space 1002 as shown in the figure, so that the flexible cables 703 and the like are less susceptible to the influence of heat from the LEDs and heat sink of the light source device 13. These flexible cables 703 and the like can use parts with dimensions such as a specified length, and are supported or covered by the cover 502, in other words, a case or support member.

[0111] Furthermore, as shown in FIGS. 5B and 11 , the space-floating image display device of the first embodiment is designed to accommodate the bottom-side projection retroreflective optical system, with the image display device 1 positioned roughly vertically. The distance between the retroreflective member 5 and the image display device 1 (approximately the same distance as the distance LB in FIG. 5B ) is larger on the bottom side of the liquid crystal panel 11, where the space for routing the flexible cable 703 and other components is greater. The space on the top side of the liquid crystal panel 11 is narrower than the space on the bottom side, which is disadvantageous in terms of routing and heat, so the routing space is provided on the bottom side. In the space on the bottom side, the flexible cable 703 is positioned at the lowest position, excluding the cover 502f. This arrangement allows heat from the light source unit 31A of the light source assembly to escape vertically from bottom to top, making the flexible cable 703 and other components less susceptible to the heat.

[0112] 17 and other figures, the space floating image display device of the first embodiment has the video signal processing board 704 and power supply board 705 arranged vertically such that the video signal processing board 704 is on the lower side and the power supply board 705 is on the upper side. The video signal processing board 704, which can be connected to the flexible cable 703 arranged in the space on the lower side, is arranged on the back side of the light source assembly, near the flexible cable 703. Because the flexible cable 703 and the video signal processing board 704 are arranged below the power supply board 705, they are less susceptible to the effects of heat from the power supply board 705.

[0113] 5B and other figures, the floating-in-space image display device of the first embodiment is arranged in a bottom-side protrusion manner in consideration of system implementation, and the aerial sensor 50 is arranged on the top side of the liquid crystal panel 11, where the distance between the retroreflective member 5 and the image display device 1, in other words the protrusion distance of the floating-in-space image 3, is smaller. This allows the support member for the aerial sensor 50 to be made smaller, and the overall configuration of the device, including the aerial sensor 50 and the cover 502 including the support member, can be made compact and thin.

[0114] <First example of kiosk terminal configuration> Next, with reference to FIG. 20 and subsequent figures, a configuration example of a kiosk terminal will be described as an implementation example of a space floating image display system configured to include the space floating image display device of the first embodiment.

[0115] Kiosk terminals are information terminals that allow an unspecified number of people to access necessary information and use various services through a man-machine interface or user interface such as a touch panel. Kiosk terminals are installed in public facilities, transportation facilities, entertainment facilities such as amusement parks, and more recently, inside convenience stores. Kiosk terminals are also used to sell various tickets and for government services such as issuing resident registration certificates.

[0116] In the following description of the embodiments, an information terminal having a specific configuration is referred to as a "kiosk terminal." Instead of the term "kiosk terminal," it may be referred to as an "information terminal," an "information display device," an "information processing terminal," a "ticket issuing terminal," a "document issuing terminal," an "administrative terminal," or a "service terminal." The term "kiosk terminal," which is primarily used in the description of the embodiments, is used as a representative example of these terms.

[0117] First, for comparison, FIG. 20 shows a perspective view of a configuration example of a conventional kiosk terminal 2000. This kiosk terminal 2000 includes a metal housing 501 having a height of, for example, 120 to 50 cm. The height of the housing 501 is determined taking into account the height of the user. A liquid crystal display screen 2001 and input buttons 2002 are provided on the inclined front surface 501a of the housing 501, which faces the user. The liquid crystal display screen 2001 is a part of a liquid crystal display device and is a screen with a touch panel that displays various information and accepts touch operations by the user. The input buttons 2002 are physical buttons for inputting a user's unique PIN number or the like, or touch buttons on a screen configured as a touch panel. In addition, a dispenser 2003 is provided in a portion near the front surface 501a of the housing 501. The dispenser 2003 is a dispenser for dispensing items, such as issued tickets or government documents, that are the result of operations on the kiosk terminal 2000.

[0118] FIG. 21 shows a perspective view seen from diagonally above right as an example of the external configuration of a kiosk terminal 2100 that implements the space-floating image display device of the first embodiment as shown in FIGS. 10 to 19. FIG. 21 shows a first configuration example of a kiosk terminal. Housing 501 in FIG. 21 has a configuration roughly similar to housing 501 in FIG. 5B, and the dimensions in the depth direction, etc. are specified. Housing 501 has an access port 2003 and the like in the lower part, which is not shown in FIG. 5B, and also has a human presence sensor 2106, for example, near the ground. Inside the lower part of housing 501, a control device, communication device, power supply device, etc. that constitute kiosk terminal 2100 are housed.

[0119] Kiosk terminal 2100 in Fig. 21 differs from kiosk terminal 2000 in Fig. 20 in the following respects. Kiosk terminal 2100 in Fig. 21 has, on front surface 501a of housing 501, liquid crystal display screen 2101, which is a liquid crystal display device, at the top, as in Fig. 20, and in addition, has, on the bottom, space-floating image display unit 2102 for displaying space-floating image 3. This space-floating image display unit 2102 is configured from the space-floating image display device of embodiment 1. In other words, kiosk terminal 2100 has two screens, liquid crystal display screen 2101 and space-floating image display unit 2102, which display two types of images, and is configured such that front surface 501a is divided into two display units, liquid crystal display screen 2101 and space-floating image display unit 2102.

[0120] In the configuration example of Fig. 21, of the two screens, the screen of the space-floating image display unit 2102 is used as the basis. This screen is also referred to as the first screen. On this first screen, an image by the space-floating image 3 is displayed as a user interface. Examples of images include an avatar and an operation menu. Fig. 21 shows an example in which an avatar 2105 (in other words, a human figure, a concierge) that guides users to services and the like is displayed by the space-floating image 3 on the first screen.

[0121] The first screen of the space floating image display unit 2102 is basically an area of ​​a predetermined size in both the vertical and horizontal directions. In this example, the first screen has a slightly horizontally long size.

[0122] On the other hand, the liquid crystal display screen 2101 is, for example, a liquid crystal touch panel screen equipped with a touch sensor, and can display any image, but is used for purposes such as displaying advertisements, for example, like a general kiosk terminal. The liquid crystal display screen 2101 is also referred to as the second screen.

[0123] In a modified example, the second screen, which is the liquid crystal display screen 2101, may be used as a user interface such as an operation menu in combination with the first screen of the space floating image display unit 2102.

[0124] As a modified example, it is also possible to configure the device without the second screen, which is the liquid crystal display screen 2101.

[0125] Also, as a modified example, both the avatar and the operation menu may be displayed as one Space Floating Image 3 on the first screen of the Space Floating Image Display Unit 2102 in Fig. 21. However, since the size of the first screen is limited, if both are displayed on the first screen, the displayed content may be small and detailed, making it difficult to see. Therefore, in the example of Fig. 21, the display switching etc. is controlled so that one of the avatar and the operation menu is displayed as large as possible on the first screen.

[0126] Of course, the positional relationship between the two screens, the liquid crystal display screen 2101 and the space-floating image display unit 2102, is not limited to the example configuration in FIG. 21 and is possible. For example, the top-bottom arrangement of these two screens may be reversed. Also, the two screens may be arranged side by side on the left and right on the front surface 501a. However, in a configuration in which the kiosk terminal 2100 is equipped with the space-floating image display unit 2102 in addition to the liquid crystal display screen 2101, it is more preferable in terms of the arrangement of the components within the housing 501 to arrange the liquid crystal display screen 2101 on the upper side and the space-floating image display unit 2102 on the lower side, as shown in FIG. 21.

[0127] Furthermore, in the case of a configuration having two screens as shown in FIG. 21, to make it easier for the user to understand that the two screens are the liquid crystal display screen 2101 and the space-floating image display unit 2102, a message to that effect, such as "This is a liquid crystal screen" or "This is a space-floating image," may be displayed on each screen. This improves usability for the user. Furthermore, the message may not be displayed on the screen itself, but may be physically displayed in advance in a position near the frame of each screen, such as "Liquid Crystal Screen" or "Space-floating Image."

[0128] In the example of Fig. 21, a user of kiosk terminal 2100 can use the services of kiosk terminal 2100 while viewing the image displayed on liquid crystal display screen 2101 as well as the image of space-floating image 3 displayed on space-floating image display unit 2102. For example, the user can operate the operation menu displayed as space-floating image 3 on space-floating image display unit 2102 by following the operation guidance provided by avatar 2105 based on space-floating image 3. Avatar 2105 provides operation guidance to the user using images and audio.

[0129] Therefore, the user feels as if a real person is present on the kiosk terminal 2100. Moreover, the avatar carefully explains to the user how to operate the kiosk terminal 2100. Therefore, even a user who is using the kiosk terminal 2100 for the first time can operate the kiosk terminal 2100 more easily and receive the desired service without any confusion.

[0130] Note that the kiosk terminal 2100 may normally keep the display on at least one of the two screens, the liquid crystal display screen 2101 and the space-floating image display unit 2102, in a sleep state, and when the motion sensor 2106 or the like detects that a person is approaching the front surface 501a of the housing 501, it may start the display on at least one of the two screens, the liquid crystal display screen 2101 and the space-floating image display unit 2102. For example, when the motion sensor 2106 detects that a person is approaching, the kiosk terminal 2100 may first display the avatar 2105 as the space-floating image 3 on the space-floating image display unit 2102, and start operation guidance or the like.

[0131] The method for forming the Space Floating Image 3 in the Space Floating Image Display Unit 2102 is a bottom-side protrusion method as shown in FIG. 5B, which uses the aforementioned retroreflective optical system. The user operates buttons on the operation menu of the Space Floating Image 3 with their fingers or the like. At that time, the surface of the Space Floating Image 3 protrudes and floats forward from the retroreflective member 5 on the front surface 501a of the housing 501, so it is difficult for the fingers or the like to come into contact with the retroreflective member 5 on the front surface 501a. In particular, the bottom side of the Space Floating Image 3 protrudes forward more than the top side. Therefore, when buttons on the operation menu are located at the bottom of the Space Floating Image 3, it is preferable because it is difficult for the user to physically come into contact with the back when pressing the buttons or the like.

[0132] In the configuration example of FIG. 21, the above-described airborne sensor 50 is disposed on the rear side of the frame portion between the two screens on the front surface 501a of the housing 501.

[0133] As a modified example, a camera may be provided at any position on the housing 501 of the kiosk terminal 2100. For example, stereo cameras may be provided on the left and right sides of the housing 501. The kiosk terminal 2100 may use images from the cameras to detect that a person has approached the front surface 501a of the housing 501. The kiosk terminal 2100 may use images from the cameras to identify and authenticate users.

[0134] The kiosk terminal 2100 may also be provided with a speaker or the like at any position on the housing 501. The kiosk terminal 2100 may use the speaker or the like to output operation sounds, operation guidance, and the like to the user.

[0135] FIG. 22 is an explanatory diagram of the internal structure of the kiosk terminal 2100 of FIG. 21. FIG. 22 shows a YZ cross-sectional view of the interior when the upper part of the housing 501 of FIG. 21 is viewed from the X-axis direction corresponding to the right side. The upper part of the housing 501 has a sloped front surface 501a in the YZ cross-section, and is roughly trapezoidal or right-angled triangular in shape. Within the space inside the housing 501, an upper space 2210 is provided with a liquid crystal display device including an LCD screen 2101, etc. The lower space 2220 is provided with the space-floating image display device of the first embodiment. Specifically, a retroreflective member 5 is arranged in line with the front surface 501a, and the image display device 1 is arranged in the space 2220 so as to stand in the Z-axis direction, which is the vertical direction, as in FIG. 17.

[0136] Image light from the liquid crystal panel 11 of the image display device 1 is emitted forward in the Y axis and enters the retroreflective member 5. The incident image light is retroreflected by the retroreflective member 5 and exits in a direction corresponding to a predetermined angle α. The exiting image light forms a real image, a floating image 3, at a position a predetermined distance from the retroreflective member 5. This floating image 3 can be viewed favorably from the user's eye UE in the line of sight corresponding to the angle α.

[0137] The user can operate the operation menu, etc. displayed as the floating image 3 with his / her fingers UH, etc. The aerial sensor 50 detects the position of the operation, etc. The control device connected to the aerial sensor 50 by communication detects the user's operation based on the detection signal of the aerial sensor 50 and performs control according to the detected operation. For example, the control device changes the display content of the floating image 3 in accordance with the operation, i.e., the content of the video signal to the video display device 1.

[0138] The inclined surface that is the front surface 501a of the housing 501 and the retroreflective member 5 are arranged at a predetermined angle β with respect to the horizontal plane, for example. This angle β is larger than the similar angle in the case of the system shown in FIG. 5A, and the inclined surface that is the front surface 501a can be made to be a surface that is close to vertical. Accordingly, the dimensions in the depth direction of the housing 501, for example, the dimension 2231 at the top and the dimension 2232 at the bottom, can be made smaller than the similar dimensions in the case of the system shown in FIG. 5A. Furthermore, the space-floating image display device of the first embodiment can be compactly housed within the housing 501, which has limited space in the depth direction.

[0139] At the same time, as described above, the influence of heat from the light source unit 31A on the flexible cable 703 and the like can also be reduced. In the space 2230 inside the housing 501, heat generated by the light source unit 31A and the power supply board 705 flows from bottom to top in the Z-axis direction, which corresponds to the vertical direction. The flexible cable 703 and the like arranged at the bottom in the space 2230 are less affected by the heat. If the housing 501 is provided with a mechanism for ventilation or cooling, for example, ventilation holes on the back surface of the housing 501, the heat from the light source unit 31A and the like flows to the outside as ventilation passes through the ventilation holes.

[0140] As a modified example, the sensing system using the aerial sensor 50 may be used to detect whether a person has approached the front surface 501a of the kiosk terminal 2100. Light emitted from the position of the aerial sensor 50 shown in the figure is emitted along the surface of the floating image 3 to the end. Therefore, if there is a human torso or the like ahead, it can be detected as reflected light.

[0141] <Second example of kiosk terminal configuration> Fig. 23 shows a perspective view seen from diagonally above right as an example of the external configuration of a kiosk terminal 2300 equipped with the space floating image display device of embodiment 1. Fig. 23 shows a second configuration example of a kiosk terminal. The kiosk terminal 2300 in Fig. 23 differs from the kiosk terminal 2100 in Fig. 21 in the following ways.

[0142] 23 does not have a liquid crystal display screen 2101 made of a liquid crystal display device on its front surface 501a, but has a space-floating image display unit 2301 on almost the entire surface. This space-floating image display unit 2301 is configured by the space-floating image display device of embodiment 1. In other words, the kiosk terminal 2300 has one screen made of the space-floating image 3 displayed on the space-floating image display unit 2301.

[0143] In the configuration example of Fig. 23, an image by Space Floating Image 3 is displayed as a user interface on the screen of Space Floating Image Display Unit 2301. The image may be, for example, an avatar or an operation menu. Fig. 23 shows an example in which, on this screen, Space Floating Image 3 is used to display an avatar 2305 that guides users to services and an operation menu 2306 in parallel, one above the other. On the screen of Space Floating Image Display Unit 2301, the avatar 2305 and the operation menu 2306 may be displayed by switching between them.

[0144] The screen of the space-floating image display unit 2301 is basically an area of ​​a predetermined size in both the vertical and horizontal directions. In this example, this screen has a vertically long size. A space-floating image display device equipped with a light source assembly 30 as shown in FIG. 17 can ensure this screen size. The screen size of the space-floating image display unit 2301 is, for example, 10 to 20 inches.

[0145] 23, a user of the kiosk terminal 2300 can use the services of the kiosk terminal 2300 while watching the image of the space-floating image 3 displayed on the relatively large-sized space-floating image display unit 2301. For example, the user can operate the operation menu 2306 displayed as the space-floating image 3 by following the operation guidance of the avatar 2305 of the space-floating image 3.

[0146] 23, the above-mentioned aerial sensor 50 is disposed on the back side of the frame portion above the screen of the space floating image display unit 2301 on the front surface 501a of the housing 501.

[0147] FIG. 24 is an explanatory diagram of the internal structure of kiosk terminal 2300 of FIG. 23. FIG. 24 shows a YZ cross-sectional view of the interior when the upper part of housing 501 of FIG. 23 is viewed from the X-axis direction corresponding to the right side. In the YZ cross-section, the upper part of housing 501 has a generally trapezoidal shape with front surface 501a being a slope. In the configuration example of FIG. 24, the height dimension of housing 501 can be shortened by the amount corresponding to the omission of liquid crystal display screen 2101 of FIG. 22. Alternatively, when the height dimension of housing 501 is the same as that of FIG. 22, the screen size of space-floating image display unit 2301 may be increased by using a space-floating image display device of a larger size overall.

[0148] The spatial floating image display device of embodiment 1 is arranged in a space 2430 within the housing 501. Specifically, a retroreflective member 5 is arranged to cover almost the entire surface of the front surface 501a, and the image display device 1 is arranged in the space 2430 so as to stand in the Z-axis direction, which is the vertical direction, as in Figure 17.

[0149] Image light from the liquid crystal panel 11 of the image display device 1 is emitted forward in the Y axis and enters the retroreflective member 5. The incident image light is retroreflected by the retroreflective member 5 and exits in a direction corresponding to a predetermined angle α. The exiting image light forms a real image, a floating image 3, at a position a predetermined distance from the retroreflective member 5. This floating image 3 can be viewed favorably from the user's eye UE in the line of sight corresponding to the angle α.

[0150] The inclined surface that is the front surface 501a of the housing 501 and the retroreflective member 5 are arranged at a predetermined angle β with respect to the horizontal plane, for example. This angle β is larger than the similar angle in the case of the system shown in FIG. 5A, and the inclined surface that is the front surface 501a can be made to be a surface that is close to vertical. Accordingly, the dimensions in the depth direction of the housing 501, for example, the dimension 2431 at the top and the dimension 2432 at the bottom, can be made smaller than the similar dimensions in the case of the system shown in FIG. 5A. Furthermore, the space-floating image display device of the first embodiment can be compactly housed within the housing 501, which has limited space in the depth direction.

[0151] At the same time, as described above, the influence of heat from the light source unit 31A on the flexible cable 703 and the like can also be reduced. In the space 2430 inside the housing 501, heat generated by the light source unit 31A and the power supply board 705 flows from bottom to top in the Z-axis direction, which corresponds to the vertical direction. The flexible cable 703 and the like arranged at the bottom inside the space 2430 are less affected by the heat. If the housing 501 is provided with a mechanism for ventilation or cooling, for example, ventilation holes on the back surface of the housing 501, the heat from the light source unit 31A and the like flows to the outside as ventilation passes through the ventilation holes.

[0152] As described above, the space-floating image display device of the first embodiment can be compactly housed and mounted in the housing of a space-floating image display system such as a kiosk terminal, and is easy to mount even when the depth dimension of the housing of the space-floating image display system is limited. As shown in Figures 5B, 22, and 24, the space-floating image 3 is a bottom-side protrusion type, and the image display device 1 can be placed vertically within the system housing 501, and the retroreflective member 5 can be positioned to align with the front surface 501a, which is an inclined surface, so the space-floating image display device of the first embodiment is easy to mount in the system.

[0153] As described above, the flexible cable 703 and the like are routed in the lower space inside the housing 501 of the space-floating image display system such as a kiosk terminal, which prevents deterioration of the heat-sensitive flexible cable 703 and the like. Also, in the case where a conventional system such as a general kiosk terminal has a housing 501 with a limited depth dimension as shown in Fig. 5B, the space-floating image display device of the first embodiment can be easily accommodated by reusing the housing 501.

[0154] <Example of light source device configuration> 25A to 25G, a configuration example of light source assembly 30 applicable as light source device 13 of the space floating image display device according to the above-mentioned embodiment 1 will be described. In this configuration example, the configuration of an optical system related to a light source device that improves light utilization efficiency by 1.8 times by using polarization conversion is shown.

[0155] 25A, 25B, 25C, 25D, and 25E show a configuration example of a light source assembly 30, which is a light source device 13. FIGS. 25A and 25E show an embodiment in which a sub-reflector is not provided, while FIGS. 25B and 25C show a modified embodiment in which sub-reflectors 310 and 308 are provided. FIG. 25A is a perspective view of the light source assembly 30 in the embodiment. The X, Y, and Z axes shown correspond to the axes in FIG. 17 and other figures. FIG. 25E corresponds to a longitudinal cross-sectional view of a portion of FIG. 25A. FIG. 25B is an enlarged perspective view of a portion of a unit 312 corresponding to a light source section in the modified embodiment. FIG. 25C is a longitudinal cross-sectional view of a portion including the unit 312 in FIG. 25B and the subsequent polarization conversion element 21 and other components. FIG. 25D is an enlarged view of a portion of a reflective surface 307 of a light guide 306 in the embodiment.

[0156] 25A and 25E, the light beam assembly 30 has, in the Z-axis direction, a unit 312 including an LED 12 as a light source and a reflector 300, a polarization conversion element 21, and a light guide 306 as a reflective light guide. The polarization conversion element 21 is disposed a predetermined distance from the unit 312 in the Z-axis direction, and the light guide 306 is disposed after the polarization conversion element 21. A diffuser plate 206 is disposed in the Y-axis direction relative to the light guide 306. The liquid crystal panel 11 is disposed on the upper surface side of the diffuser plate 206.

[0157] 25A to 25E show a state in which the LEDs 14 constituting the light source are mounted on the substrate 102. These are configured as a unit 312 having a plurality of blocks, each consisting of a reflector 300 and an LED 14 as a pair. The plurality of blocks are arranged in the X-axis direction. The plurality of reflectors 300 may be formed as a single unit as shown in the drawings.

[0158] The heat sink 330 is not shown in Figures 25A, 25F, and 25G. The embodiment of Figure 25E illustrates an example configuration of the heat sink 330. The modified example of Figure 25C illustrates another example configuration of the heat sink 330. The heat sink 330 in Figure 25E has a portion that contacts the rear side of the substrate 102 along the Y axis and a portion that contacts the lower side of the Z axis so as to cover the reflector 300. The heat sink 330 in Figure 25B is provided in contact with the rear side of the substrate 102 along the Y axis. In general, the metallic substrate 102 generates heat. In particular, the substrate 102 generates heat from the LEDs 14, which are light sources provided on the surface side. Therefore, the heat sink 330 is provided to cool the substrate 102.

[0159] A reflector 300 is disposed on the surface of the substrate 102 above the LED 14 in the Y-axis direction. The reflector 300 reflects the divergent light emitted from the LED 14 with its optical axis along the Y-axis in the direction of the Z-axis, converting it into a substantially parallel beam of light. This substantially parallel beam of light is indicated by beam φ5 in Figures 25E and 25C.

[0160] The reflecting 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. 25B. In this embodiment, the reflecting surface of the reflector 300 is a paraboloid, and the center of the light-emitting surface of the LED 14, which is a surface light source, is located at the focal position of the paraboloid. Furthermore, due to the characteristics of the paraboloid, light emitted from the four corners of the light-emitting surface of the LED 14 also becomes approximately parallel light beams, and only the emission direction differs. Therefore, even if the light-emitting part has an 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 21 and the reflector 300, which is located downstream, is short.

[0161] Furthermore, for the reasons described above, an optical system can be realized that can reduce the decrease in light conversion efficiency even if the mounting position of the LED 14 is shifted in the XZ plane with respect to the focal point of the corresponding reflector 300. Furthermore, even if the mounting position of the LED 14 varies in the Y-axis direction, the converted parallel light beam simply moves in the YZ plane, which can significantly reduce the mounting accuracy of the LED 14, which is a surface light source.

[0162] In this embodiment, the reflector 300 has been described as having a reflective surface in which part of a paraboloid is cut out along the meridian (north-south line), but the LED 14 may be disposed in the cut-out part of the paraboloid as the reflective surface.

[0163] 25E and 25C, the present embodiment is characterized in that the divergent light from the LED 14 is reflected by a parabolic surface 321 to be converted into substantially parallel light, and then the parallel light is incident on the end face of the polarization conversion element 21 at the subsequent stage, where it is aligned into a specific polarization by the polarization conversion element 21. The polarization conversion element 21 is formed, for example, by combining a polarization conversion prism and a wave plate 213. This characteristic configuration increases the light utilization efficiency by 1.8 times compared to the prior art example, thereby realizing a highly efficient light source.

[0164] At this time, the substantially parallel light obtained by reflecting the divergent light from the LED 14 by the parabolic surface 321 is not all uniform. Therefore, in this embodiment, the luminous flux φ6 as the substantially parallel light that has passed through the polarization conversion element 21 is made incident on the liquid crystal panel 11 in a direction perpendicular to the liquid crystal panel 11 by adjusting the angular distribution of the reflected light by the reflecting surfaces 307 having a plurality of inclinations in the light guide 306.

[0165] In this example, the LEDs 14 are arranged so that the direction of the chief ray of the light entering the reflector 300 is approximately parallel to the direction of the light entering the liquid crystal panel 11. In the example of Fig. 25A etc., they are arranged approximately parallel along the Y axis. This arrangement is easy to implement in terms of design, and it is also preferable to arrange the heat source below the light source device 13, because air can escape from the bottom to the top, thereby reducing the temperature rise of the LEDs 14.

[0166] 25C, in order to improve the capture rate of divergent light from the LED 14, the following configuration is provided to capture the light beam that cannot be captured by the reflector 300. In this modification, a portion 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 toward the light guide 306. Specifically, the light beam that cannot be captured by the reflector 300 is reflected by the sub-reflector 308 provided on the light-shielding plate 309 disposed diagonally above the exit side of the reflector 300. The reflected light beam is further reflected by the slope of the sub-reflector 310 provided below the reflector 300 on the substrate 102. The reflected light beam is incident in the Z-axis direction on the effective area of ​​the polarization conversion element 21 at the subsequent stage. This further improves the light utilization efficiency.

[0167] In FIG. 25C, the light blocking plate 309 is connected to a light blocking plate 402 connected to one end of the diffusion plate 206 and a light blocking plate 410 provided on the incident surface side of the polarization conversion element 21, for example.

[0168] 25C, the substantially parallel light beams aligned in the Z-axis direction by the polarization conversion element 21 to a specific polarization are reflected by the reflective surface 307 of a reflective shape provided on the surface of the light guide 306 toward the liquid crystal panel 11 disposed opposite the light guide 306 in the Y-axis direction. At this time, the light amount distribution of the light beams incident on the liquid crystal panel 11 is optimally designed by the shape and arrangement of the reflector 300 described above, and the cross-sectional shape, inclination, and surface roughness of the reflective surface 307 of the light guide 306.

[0169] The shape of the reflecting surface 307 provided on the surface of the light guide 306 is such that a plurality of reflecting surfaces are arranged opposite the exit surface of the polarization conversion element 21, and the inclination, area, height, and pitch of the reflecting surface 307 are optimized according to the distance from the polarization conversion element 21, thereby achieving a desired light intensity distribution of the light beam incident on the liquid crystal panel 11, as described above. Note that only a portion of the reflecting surface 307 is shown in Figures 25E and 25C.

[0170] The overall shape of light guide 306 is such that the inclination in the X-axis direction increases from the side closer to unit 312 to the side farther from unit 312, and the distance between the opening in the Y-axis direction and diffuser plate 206 is large on the side closer to unit 312 of reflecting surface 307, and the distance between the opening and diffuser plate 206 is small on the side farther from unit 312. In addition, sidewall 400 is provided on the outer side of light guide 306 in the X-axis direction, so that light that is incident on and reflected by reflecting surface 307 does not escape to the outside.

[0171] As shown in FIG. 25D, the reflecting surface 307 of the light guide 306 has multiple inclinations on one surface. This allows for more accurate adjustment of the reflected light. FIG. 25D shows how, for example, light rays R7 to R10 in the light beam φ6 from the polarization conversion element 21 are reflected at respective inclination points P7 to P10 on the reflecting surface 307. Note that the reflecting surface 307 may have multiple inclinations on one surface, and the area used as the reflecting surface 307 may be a multi-surface, polyhedral, or curved surface. Furthermore, the diffusing effect of the diffuser 206 in FIG. 25A achieves a more uniform light intensity distribution for the reflected light from the reflecting surface 307. The light incident on the diffuser 206 on the side closer to the LED 14 in the Z-axis direction achieves a uniform light intensity distribution by varying the inclination of the reflecting surface 307.

[0172] In this embodiment, a plastic material such as heat-resistant polycarbonate is used as the base material of the reflecting surface 307. The angle of the reflecting surface 307 corresponding to the light immediately after emission from the λ / 2 plate (half-wave plate) 213, which is the wave plate 213, is designed to change depending on the distance between the λ / 2 plate 213 and the reflecting surface 307.

[0173] In this embodiment, the LED 14 and the reflector 300 are arranged close to each other in some areas, but heat can be dissipated into the space on the opening side of the reflector 300, reducing the temperature rise of the LED 14 and reducing the impact on the relay substrate 702 and flexible cables 701 and 703. As another modification, the arrangement of the substrate 102 and the reflector 300 in the Y-axis direction may be upside down compared to the arrangement shown in Figures 25A to 25E.

[0174] However, when the substrate 102 is disposed above the reflector 300, the substrate 102 is closer to the liquid crystal panel 11, which may make the layout difficult. Therefore, as shown in the figure, disposing the substrate 102 below the reflector 300, farther from the liquid crystal panel 11, simplifies the internal configuration of the device.

[0175] 25E and 25C, a light shielding plate 410 may be provided on the light incident surface of the polarization conversion element 21 to prevent unnecessary light from entering the optical system at a subsequent stage. The illustrated light shielding plate 410 is disposed in areas above and below the effective area of ​​the incident surface in the Y-axis direction. With this configuration, a light source device 13 that suppresses temperature rise can be realized.

[0176] The polarizer provided on the light incident surface of the liquid crystal panel 11 absorbs the light beam with uniform polarization in this embodiment, thereby reducing the temperature rise. If the polarization direction of the light beam with uniform polarization in this embodiment rotates when reflected by the light guide 306, some of the light is absorbed by the polarizer provided on the light incident surface of the liquid crystal panel 11. Furthermore, the temperature of the liquid crystal panel 11 also rises due to absorption by the liquid crystal itself in the liquid crystal panel 11 and a temperature rise caused by light incident on the electrode pattern. However, since there is sufficient space between the reflecting surface 307 of the light guide 306 and the liquid crystal panel 11, natural cooling is possible.

[0177] 25E does not include sub-reflectors 308 and 310 as in FIG. 25C, and light-shielding plate 401 connects diffuser plate 206 to the upper end of reflector 300. On the incident surface between light guide 306 and diffuser plate 206, polarization conversion element 21 and light-shielding plate 410 are disposed at the bottom, and the top is open. Light-shielding plate 401 in FIG. 25E and light-shielding plates 309 and 402 in FIG. 25C can also reduce the effects on relay substrate 702 and flexible cables 701 and 703.

[0178] Figures 25F and 25G show modified examples of light source device 13 of Figures 25E and 25C. Figures 25F and 25G illustrate modified examples of a portion of light source device 13. The rest of the configuration is the same as that of light source device 13 shown in Figures 25E and 25C, so illustrations and repeated explanations will be omitted. Figures 25F and 25G show YZ cross sections.

[0179] First, in the modified example shown in FIG. 25F, the sub-reflector 310 on the substrate 102 of FIG. 25C has a recess 319 and a protrusion 318. FIG. 25B also shows the recess and protrusion of the sub-reflector 310 extending in the Y-axis direction. The height of the recess 319 is adjusted to be lower than the phosphor 114 so that the chief ray f1 of the fluorescence output in the Z-axis direction (i.e., horizontal direction) from the phosphor 114 arranged above the LED 14 can pass through the recess 319. The chief ray f1 of the fluorescence is illustrated in FIG. 25F as a straight line extending in a direction parallel to the Z-axis. Furthermore, the height of the light-shielding plate 410 is adjusted to be lower in the Y-axis direction relative to the position of the phosphor 114 so that the chief ray f1 of the fluorescence output in the horizontal direction from the phosphor 114 can enter the effective area of ​​the polarization conversion element 21 without being blocked by the light-shielding plate 410.

[0180] Furthermore, the reflective surface of the convex portion 318 of the uneven top of the sub-reflector 310 reflects the light reflected by the sub-reflector 308 in FIG. 25C in order to guide the light reflected by the sub-reflector 308 to the light guide 306. The light reflected by the convex portion 318 is reflected by the reflective surface 321 of the reflector 300 and travels in the Z-axis direction toward the polarization conversion element 21. Therefore, the height of the convex portion 318 is adjusted so that the light reflected by the sub-reflector 308 can be reflected and incident on the effective area of ​​the polarization conversion element 21 in the subsequent stage. This can further improve the light utilization efficiency.

[0181] 25B, the sub-reflector 310 is arranged so as to extend in one direction corresponding to the X-axis, and has an uneven shape. Furthermore, the top of the sub-reflector 310 has unevenness with one or more recesses periodically arranged in one direction. By using such an uneven shape, it is possible to configure the sub-reflector 310 so that the chief ray f1 of the fluorescence output laterally from the phosphor 114 is incident on the effective area of ​​the polarization conversion element 21.

[0182] Furthermore, the concave and convex shapes of sub-reflector 310 are periodically arranged at a pitch such that recesses 319 are located at positions where LEDs 14 are located in the X-axis direction. That is, each of phosphors 114 is periodically arranged along one direction corresponding to the arrangement pitch of recesses 319 of the concave and convex shapes of sub-reflector 310. Note that when LEDs 14 are provided with phosphors 114, phosphors 114 may be expressed as light-emitting portions of the light source.

[0183] 25G, the sub-reflector 310 may be omitted. In the modification of Fig. 25G, similar to Fig. 25F, the height of the light-shielding plate 410 is adjusted to be lower in the Y-axis direction relative to the position of the phosphor 114 so that the chief ray f1 of the fluorescence output from the phosphor 114 in the Z-axis direction, which is horizontal, is incident on the effective area of ​​the polarization conversion element 21 without being blocked by the light-shielding plate 410.

[0184] 25A to 25G described above, side walls 400 may be provided to prevent dust from entering the space between the reflective surface 307 of the light guide 306 and the liquid crystal panel 11, to prevent stray light from being generated outside the light source device 13, and to prevent stray light from entering from outside the light source device 13, as shown in FIG. 25A. In FIG. 25A, the side walls 400 are schematically illustrated as transparent. When the side walls 400 are provided, the side walls 400 are arranged on both the front and back sides in the X-axis direction of the space between the polarization conversion element 21, the light guide 306, the diffuser plate 206, and the liquid crystal panel 11 so as to prevent openings from being formed on both sides in the X-axis direction. The side walls 400 may be part of the cover of the space-floating image display device.

[0185] As shown in Figures 25E and 25C, the light exit surface of the polarization conversion element 21, which emits the light beam φ6 that is polarization-converted light, faces a space 1801 surrounded by the light guide 306, the diffuser 206, the polarization conversion element 21, and the sidewall 400. Furthermore, among the inner surfaces of the sidewall 400 in the X-axis direction, a portion that covers the space to the right of the exit surface of the polarization conversion element 21 from the side in the X-axis direction, which serves as the space into which light is output from the exit surface of the polarization conversion element 21, may be a reflective surface having a reflective film or the like. That is, the surface of the sidewall 400 facing the space 1800 includes a reflective region having a reflective film. By using this portion of the inner surface of the sidewall 400 as the reflective surface, the light reflected by the reflective surface can be reused as light source light. This improves the brightness of the light source device 13.

[0186] Of the inner surfaces of the side wall 400, the surface covering the side of the polarization conversion element 21 is made to have low light reflectivity, in other words, a black surface without a reflective film. This is because if light is reflected from the side surface of the polarization conversion element 21, light with an unexpected polarization state will be generated, causing stray light. In other words, by making this surface a surface with low light reflectivity, it is possible to prevent or suppress the occurrence of stray light in the image and light with an unexpected polarization state. Furthermore, the side wall 400 may be configured to have holes through which air can pass in part to improve the cooling effect.

[0187] 25A to 25G have been described on the assumption that the light source devices 13 use the polarization conversion element 21. That is, these configurations can convert randomly polarized light from the LEDs 14 into light with a specific polarization. However, as a modified example, the polarization conversion element 21 may be omitted from these light source devices 13. In this case, the light source devices 13 can be provided at a lower cost.

[0188] The light source assembly 30 shown in the first embodiment and the like can be configured based on the above-described exemplary configuration of the light source device 13. For example, the light source device 13 shown in FIG. 25A is configured assuming a predetermined size as the display screen size of the liquid crystal panel 11 to be applied, and the light guide 306 is designed with dimensions and a shape in the Z-axis direction that match the display screen size of the liquid crystal panel 11. The dimensions of this light guide 306 are adjustable to some extent. On the other hand, as in the above-described example, if the display screen size of the liquid crystal panel 11 required for the applied system is relatively large, the required display screen size can be accommodated by combining multiple light source devices 13 shown in FIG. 25A and the like in parallel. That is, as in the first embodiment, a light source assembly 30 may be configured in which two light source devices 13 shown in FIG. 25A and the like are symmetrically arranged in one direction, and one liquid crystal panel 11 or the like is arranged in the other direction relative to the pair of light guides 306.

[0189] <Example of the configuration of a light source device> Next, an example of the configuration of light source assembly 30 that can be applied as light source device 13 of the space floating image display device according to the first embodiment will be described with reference to FIGS. 26A to 26G.

[0190] FIG. 26A is an example of a YZ cross-sectional view of the space-floating image display device shown in FIG. 17 without the cover 502, as viewed from the X-axis direction (side), and an enlarged partial view of the vicinity of the center line C. In region A of FIG. 26A , the light guide 306 is closest to the diffuser 206. The portion of the light guide 306 closest to the diffuser 206 is referred to as the nearest portion. The nearest portion is the portion with the shortest distance between the reflecting surface 307 of the light guide 306 and the light incident surface of the diffuser 206. In other words, the nearest portion is the portion with the shortest distance from the reflecting surface 307 or the light exit surface of the light guide 306 to the light incident surface of the diffuser 206. As shown in FIG. 26A , in this embodiment, the light guide 306 includes a nearest portion. Furthermore, light sources 14 are arranged on both sides of the center line C, and the nearest portion is located in the center of the light guide 306 relative to the center line C. Note that the nearest portion does not have to be located in the center of the light guide 306 as in this embodiment. Light from the light source 14 is reflected by the reflector 300, and the light reflected by the reflector 300 is reflected by the reflecting surface 307 of the light guide 306 and enters the liquid crystal display panel 11 via the diffuser 206. Of this light, a portion of the light that enters the diffuser 206 is reflected by the diffuser 206, enters the nearest portion, is reflected twice, and enters the diffuser 206.

[0191] 17, the side where the aerial sensor 50 is located is depicted as the top (upper side on the Z axis), but in FIG. 26A, the nearest part is at the uppermost position in the drawing within the shape of the light guide 306. In FIG. 26A, the side where the aerial sensor 50 is located is depicted as the right side. The drawing shown at the bottom of FIG. 26A is an enlarged view of the vicinity of the nearest part of the light guide 306 (area A).

[0192] 26A shows an enlarged view of region A (near the nearest part), from the top, liquid crystal panel 11, diffuser plate 206, and light guide 306, that is, diffuser plate 206 is disposed between liquid crystal panel 11 and light guide 306. As already explained in FIGS. 25C and 25D, reflective surface 307 provided on light guide 306 has a shape with multiple inclinations on one surface.

[0193] To explain the above-mentioned microstructure in more detail, as shown in the enlarged view of region A in Fig. 26A, light guide 306 has a reflective surface 307, and reflective surface 307 has a nearest-neighbor portion. Light reflected by reflector 300 is reflected by reflective surface 307 of light guide 306 and enters diffuser plate 206, and a portion of the light incident on diffuser plate 206 is reflected by diffuser plate 206 and enters and is reflected at the nearest-neighbor portion. Note that the light guide is not limited to the above-mentioned configuration, and may have a reflective surface and a nearest-neighbor portion.

[0194] Next, Fig. 26B is a diagram showing how light from LED 14 enters light guide 306 shown in Fig. 26A in the Z-axis direction, is reflected by reflective surface 307 of light guide 306, and travels vertically (in the negative direction of the Y-axis) toward liquid crystal panel 11. As shown in Fig. 26B, multiple reflections occur between diffuser plate 206 and the closest part of light guide 306. Here, multiple reflections refer to a phenomenon in which light is repeatedly reflected between two opposing reflective surfaces.

[0195] FIG. 26C is a view of the liquid crystal panel 11 (screen) as viewed from above. This is a view of the liquid crystal panel 11 as viewed from the direction in which the screen is viewed, i.e., the Y direction, when multiple reflections as shown in FIG. 26B occur. FIG. 26C shows the entire liquid crystal panel, with an aspect ratio of 16:10. Due to the occurrence of multiple reflections, a bright line that is brighter than other areas appears at a position corresponding to the nearest part of the light guide 306. In the present invention, the position corresponding to the nearest part of the light guide 306 is the center of the liquid crystal panel 11. Furthermore, when a 100% white image with uniform brightness is displayed on the liquid crystal panel 11, the width of this bright line can be more clearly seen.

[0196] Furthermore, the width of the bright line varies depending on the width of the nearest part. For example, as shown in FIG. 26C, when the width of the nearest part is 0.1 mm, the bright line observed on the exit surface of the liquid crystal panel 11 (liquid crystal panel) is wider than the width of the nearest part of the light guide 306. Furthermore, the bright line shown in FIG. 26C is brighter than the surrounding area of ​​the liquid crystal panel. When the bright line shown in FIG. 26C has a width of approximately 1 mm, the bright line can also be observed as a spatially floating image 3, which ultimately causes degradation of the image quality of the spatially floating image and, in some cases, leads to a deterioration in visibility.

[0197] 26D is an enlarged view of the vicinity of the nearest portion of light guide 306 shown in FIGS. 26A and 26B, i.e., region B shown in FIG. 26A. As already mentioned, the bright line shown in FIG. 26C is caused by multiple reflections occurring between diffuser 206 and the nearest portion of light guide 306. The multiple reflections occur because the reflected light from diffuser 206 and light guide 306 returns to the vicinity of the original reflection position, resulting in repeated reflections along approximately the same optical path.

[0198] FIG. 26E is a diagram showing the configuration of the nearest portion of the light guide 306 in region B. More specifically, FIG. 26E shows a shape in which a recess is provided in the nearest portion of the light guide 306 in region B. That is, two protrusions are formed in the nearest portion of the light guide 306 in region B, or protrusions are arranged on both sides of the recess. The recess has a triangular prism shape elongated in the depth direction (X-axis direction), and FIG. 26F shows a perspective view of the periphery of the recess. The recess has a shape elongated perpendicular to the direction of light reflected by the reflector 300. In this embodiment, the depth direction of the recess or protrusion is the same as the direction in which the LEDs 14 are arranged. In addition, in the Z direction, the recess has a first surface and a second surface, and the angle between the first surface and the second surface is θop. One of the two convex portions is formed by the reflective surface of the light guide 306 and the first surface, and the other is formed by the reflective surface of the light guide 306 and the second surface. The angle between the reflective surface of the light guide 306 and the first surface and the angle between the reflective surface 307 of the light guide 306 and the second surface are θtp. In this embodiment, a concave portion is formed in the center of the nearest portion, so the two θtp angles are approximately equal or equal. However, depending on the design, the two θtp angles may be different.

[0199] In this example, as shown in Figures 26E and 26F, the angle (referred to as the opening angle θop) of the lower side of the triangular prism forming the recess (the vertex in the Y-axis direction in Figures 26E and 26F) is set to, for example, 95.24 degrees, and the angles (referred to as the vertex angle θtp) of the two vertices of the light guide 306 after the recess is formed are each set to 90 degrees. In this case, for example, the length in the Y-axis direction between the line drawn in the Z-axis direction from the vertex of the lower side of the triangular prism forming the recess and the line drawn in the Z-axis direction from the vertices of the two protrusions is set to 0.046 mm. As will be described in detail later, by forming the recess (opening angle θop, vertex angle θtp) at the closest portion of the light guide 306 as shown in Figures 26E and 26F, the occurrence of multiple reflections can be effectively suppressed.

[0200] Fig. 26G is a diagram showing an example of the path of reflected light between light guide 306 having the recesses shown in Fig. 26E and Fig. 26F formed therein and diffuser 206. As shown in Fig. 26G, light that reflects from diffuser 206 at an angle close to perpendicular and enters light guide 306 is reflected twice by the recesses and does not return to the vicinity of the original reflection position on diffuser 206. As a result, multiple reflections such as those shown in Fig. 26A can be suppressed.

[0201] Here, regarding the opening angle θop of the recess, which is the angle around the recess, and the two vertex angles θtp, if the vertex angle θtp is in the range of 90±10 degrees (80 to 100 degrees), a greater effect in suppressing multiple reflections can be obtained. That is, the angle θop of the recess and the angle of the two protrusions are defined as θtp. Furthermore, if θtp is an angle within the range of 90±20 degrees (70 to 110 degrees), there is at least an effect of reducing multiple reflections.

[0202] The above-mentioned configuration can prevent the occurrence of bright lines and suppress (prevent) multiple reflections. As shown in Figures 26E and 26F, according to this embodiment, by forming a recess in the nearest part of the light guide 206, i.e., by forming two protrusions, it is possible to suppress multiple reflections occurring between the light guide 206 and the diffuser plate 206, as shown in Figure 26D. As a result, it is possible to reduce the occurrence of bright lines (linear parts with higher brightness than other parts). Therefore, it is possible to obtain a new effect of suppressing deterioration in the image quality of the spatial floating image, and as a result, preventing deterioration in visibility.

[0203] [Note] Various specific examples have been described above as embodiments of the present disclosure. However, the present disclosure is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have described the entire system in detail for easy understanding, but the present disclosure is not limited to systems that include all of the described configurations. It is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with another configuration. It is also possible to combine the embodiments. Unless otherwise specified, each component may be singular or plural.

[0204] The light source device described above is not limited to the space floating image display device, but can also be applied to various display devices and systems such as head-up display devices, tablet terminals, digital signage, and the like.

[0205] The technology according to this embodiment displays high-resolution, high-brightness floating images in a floating state, allowing users to operate the device without worrying about contact infection. Applying the technology according to this embodiment to a system used by an unspecified number of users reduces the risk of contact infection and provides a contactless user interface that can be used without anxiety. The present invention, which provides such technology, contributes to the achievement of the United Nations' Sustainable Development Goals (SDGs), "Good Health and Well-Being."

[0206] Furthermore, the technology according to the above-described embodiment reduces the divergence angle of the emitted image light and aligns it with a specific polarization, thereby efficiently reflecting only the normal reflected light from the retroreflective material, resulting in high light utilization efficiency and bright, clear floating images in space. The technology according to this embodiment can provide a highly usable non-contact user interface that can significantly reduce power consumption. The present invention, which provides such technology, contributes to the achievement of the United Nations' Sustainable Development Goals (SDGs): "Build resilient infrastructure, promote inclusive and sustainable industrialization, and promote technological innovation and infrastructure" and "Make cities and human settlements sustainable."

[0207] Furthermore, the technology according to the above-described embodiment makes it possible to form a floating image using highly directional (in other words, linear) image light. The technology according to the present embodiment makes it possible to provide a non-contact user interface with low risk of people other than the user viewing the floating image, even when displaying images that require high security, such as those found in bank ATMs or train station ticket machines, or highly confidential images that should be kept secret from people directly facing the user, by displaying highly directional image light. By providing the above-described technology, the present invention contributes to "Sustainable Cities and Communities," one of the Sustainable Development Goals (SDGs) advocated by the United Nations. [Explanation of symbols]

[0208] 1...image display device, 3...space floating image, 5...retroreflective member, 11...liquid crystal panel, 13...light source device, 30, 30A, 30B...light source assembly, 31A, 31B...light source section, 32A, 32B...light guide section, 50...airborne sensor, 204, 206...diffuser plate, 306...light guide, 307...reflective surface, 330...heat sink, 502...cover, 701, 703...flexible cable, 702...relay board, 704...video signal processing board, 705...power supply board, 1001...distance, 1002...space

Claims

1. A space floating image display device that displays a space floating image, a light source device; A diffusion plate; a display panel that emits light from the light source device as image light; a retroreflective member that reflects image light from the display panel and forms the spatial floating image, which is a real image, in the air using the reflected light; The light source device includes a light source and a reflector that reflects light from the light source; a light guide that guides the light from the reflector toward the display panel, the diffusion plate is disposed between the light guide and the display panel, the light guide includes a nearest-neighbor portion having a recess; The nearest portion is a portion where the distance between the light incident surface of the diffuser plate and the reflection surface of the light guide is shortest. A floating image display device.

2. 2. The space floating image display device according to claim 1, The nearest portion further has a convex portion. A floating image display device.

3. In the spatial floating image display device according to claim 2, The protrusions are arranged on both sides of the recess in the nearest portion. A floating image display device.

4. In the spatial floating image display device according to claim 1, The recess is located in the middle of the nearest portion. A floating image display device.

5. 3. The space floating image display device according to claim 2, The angle of the convex portion is 70 degrees to 110 degrees. A floating image display device.

6. 3. The space floating image display device according to claim 2, The angle of the convex portion is 80 degrees to 100 degrees. A floating image display device.

Images