Display devices, head-up display devices, and digital signage

Abstract

To provide a technique capable of achieving a reduction in thickness of a system or a spatial floating image display apparatus and reducing influence caused by heat from a light source device or the like.SOLUTION: A display apparatus includes a light source device, an image display element that emits image light on the basis of light from the light source device, and a power supply board that supplies power to the light source device. A flexible cable or a board connected to the image display element is arranged so as to bypass a light source unit of the light source device to provide a space between the light source unit and itself, and to extend around to a rear side of the light source device. The power supply board is arranged on the rear side of the light source device and is disposed above the flexible cable and the board in a vertical direction.SELECTED DRAWING: Figure 17

Description

Technical Field

[0001] The present invention relates to the technology of a spatial floating image display device.

Background Art

[0002] As a spatial floating image display system, a display method in which an image display device directly displays an image toward the outside and a spatial screen is already known. Also, a detection system for detecting an operation on the operation surface of the displayed spatial image is already known.

[0003] As a spatial floating image display device constituting a spatial floating image display system of a prior art example, there is a configuration example in which an image display device including an image display element such as a liquid crystal panel is combined with a retroreflective member that generates a spatial floating image. The retroreflective member may also be described as a retroreflective plate, a retroreflective sheet, etc. In this configuration example, the image light from the image display device is retroreflected by the retroreflective member, and a spatial floating image is formed at a spatial position symmetric to the image display device with respect to the retroreflective member. Such a retroreflective optical system is disclosed in, for example, Patent Document 1.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the example configuration of the floating image display device having the retroreflective optical system described above, conventionally, insufficient consideration has been given to making the floating image display system thinner, that is, minimizing the depth dimension during implementation. Depending on the system implementation, the floating image display device requires that components such as the light source device, liquid crystal panel, and retroreflective plate be placed within the system housing, along with flexible printed circuit boards for driving the liquid crystal panel, in other words, flexible cables and electronic circuit boards such as relay boards. Compact arrangement of components within the system housing is required.

[0006] Furthermore, in the above configuration example, conventionally, the heat generated by the light source device, which serves as the backlight source for the LCD panel, affects heat-sensitive components such as flexible cables. Conventionally, the effects of heat from this light source device, such as component degradation, have not been adequately considered. The thinner the system, the greater the impact of the heat.

[0007] Conventional floating image display devices have room for improvement in optimizing the system, taking into account the thinning of the system, the thinning of the floating image display device including the cover, and the reduction of the effects of heat from the light source device, etc.

[0008] The purpose of this disclosure is to provide a technology related to a floating image display device that enables the miniaturization of the system and the floating image display device, as well as the reduction of the effects of heat on light sources and other components. [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 one example is as follows. One embodiment is a display device comprising a light source device, an image display element that emits image light based on light from the light source device, and a power supply board that supplies power to the light source device, wherein a flexible cable or board connected to the image display element is arranged to bypass the light source part of the light source device and wrap around to the back side of the light source device so as to create a space between the cable and the light source part of the light source device, and the power supply board is arranged on the back side of the light source device, above the flexible cable and the board in a vertical direction. [Effects of the Invention]

[0010] According to a representative embodiment of this disclosure, regarding the technology related to a floating image display device, it is possible to achieve a thinner system and floating image display device, as well as a reduction in the effects of heat from light source devices, etc. Other issues, configurations, and effects will be shown in the embodiments for carrying out the invention. [Brief explanation of the drawing]

[0011] [Figure 1A] This figure shows an example of the configuration of a retroreflective member according to one embodiment. [Figure 1B] This figure shows the location where a floating image in space is generated in a retroreflective optical system including a retroreflective member according to one embodiment. [Figure 2A] This is an explanatory diagram illustrating the generation mechanism of normal reflected light and abnormal reflected light in a perspective view of a retroreflective member according to one embodiment. [Figure 2B] This is an explanatory diagram illustrating the generation mechanism of normal reflected light and abnormal reflected light in a plan view of a retroreflective member according to one embodiment. [Figure 3A] This is an explanatory diagram of a mechanism for eliminating abnormal light rays generated when ambient light is incident on a retroreflective member according to one embodiment. [Figure 3B]It is an explanatory diagram of a mechanism for eliminating abnormal light rays generated when external light is incident on a retroreflective member according to an embodiment. [Figure 4A] It is a diagram showing a configuration example of a video display device according to an embodiment. [Figure 4B] It is a diagram showing a configuration example of a retroreflective member according to an embodiment. [Figure 5A] It is a diagram showing a design example of a system including a spatial floating video display device according to an embodiment. [Figure 5B] It is a diagram showing a design example of a system including a spatial floating video display device according to an embodiment. [Figure 6] It is a diagram showing a configuration example of an air sensor constituting a spatial floating video display device according to an embodiment. [Figure 7A] It is a schematic cross-sectional view showing a configuration example of a liquid crystal panel, a flexible cable, a substrate, etc. constituting a spatial floating video display device according to an embodiment. [Figure 7B] It is a schematic plan view showing a configuration example of a liquid crystal panel, a flexible cable, a substrate, etc. constituting a spatial floating video display device according to an embodiment. [Figure 8] As a comparative example, it is a diagram showing a configuration example of the routing of a flexible cable, etc. of a video display device. [Figure 9] It is a diagram showing a configuration example of the routing of a flexible cable, etc. of a video display device in a spatial floating video display device according to an embodiment. [Figure 10] It is a perspective view showing a schematic configuration of the spatial floating video display device of Embodiment 1. [Figure 11] It is a longitudinal cross-sectional view showing a schematic configuration of the spatial floating video display device of Embodiment 1. [Figure 12] It is a perspective view showing the configuration with a cover of the spatial floating video display device of Embodiment 1. [Figure 13] It is a perspective view showing the configuration without a cover of the spatial floating video display device of Embodiment 1. [Figure 14] It is a plan view showing the configuration with a cover of the spatial floating video display device of Embodiment 1. [Figure 15]It is a plan view showing the configuration of the space floating image display device of Embodiment 1 without a cover. [Figure 16] It is a side view showing the configuration of the space floating image display device of Embodiment 1 with a cover. [Figure 17] It is a longitudinal sectional view showing the configuration of the space floating image display device of Embodiment 1. [Figure 18] It is a perspective view showing the 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 of Embodiment 1. [Figure 19] It is a perspective view showing the 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 of Embodiment 1. [Figure 20] It is a perspective view showing a configuration example of a conventional general kiosk terminal. [Figure 21] It 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 Embodiment 1. [Figure 22] It is a longitudinal sectional view in the first configuration example of the kiosk terminal. [Figure 23] It 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 Embodiment 1. [Figure 24] It is a longitudinal sectional view in the second configuration example of the kiosk terminal. [Figure 25A] It is a structural view showing a specific configuration example of a light source device according to an embodiment. [Figure 25B] It is a perspective view showing a configuration example of a light source unit in a specific configuration example of a light source device according to an embodiment. [Figure 25C] It is a sectional 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 25D] It is a view showing a reflecting surface of a light guide of a light guide unit in a specific configuration example of a light source device according to an embodiment. [Figure 25E] It is a sectional 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 25F]This is a cross-sectional view of an LED, reflector, light shield, etc., in a specific configuration example of a light source device according to one embodiment. [Figure 25G] This is a cross-sectional view of an LED, light shield, etc., in a specific configuration example of a light source device according to one embodiment. [Modes for carrying out the invention]

[0012] Embodiments of the present invention will be described in detail below with reference to the drawings. However, the present invention is not limited to the embodiments described below (also referred to as "this disclosure" or "examples"). The present invention extends to the spirit of the invention or the scope of the technical ideas described in the claims, or their equivalents. Furthermore, the configurations of the embodiments described below are merely illustrative, and various changes and modifications are possible within the scope of the technical ideas disclosed herein by those skilled in the art.

[0013] Furthermore, in the drawings used to illustrate the present invention, components having the same or similar functions are assigned 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 embodiments, images floating in space are referred to as "floating images." Instead of this term, you may also use terms such as "aerial image," "spatial image," "floating image," "floating optical image of a displayed image," or "floating optical image of a displayed image." The term "floating image" primarily used in the description of embodiments is used as a representative example of these terms.

[0014] This disclosure relates to a display system capable of displaying images as floating images inside or outside a store space by transmitting images from a large-area image light source through a transparent partitioning material such as the glass of a shop window. This disclosure also relates to a large-scale digital signage system composed of multiple such display systems.

[0015] According to the following embodiment, for example, a high-resolution image can be displayed in a floating state on the glass surface of a shop window or on a light-transmitting plate. In this case, by making the divergence angle of the emitted image light small, i.e., acute, and further aligning it to a specific polarization, only the normal reflected light can be efficiently reflected by the retroreflective material. As a result, the light utilization efficiency is high, and ghost images that occur in addition to the main floating image, which was a problem in conventional retroreflection methods, can be suppressed, and a clear floating image can be obtained.

[0016] Furthermore, the device including the light source of this disclosure can provide a novel and highly usable floating image display system that can significantly reduce power consumption. In addition, the technology of this disclosure can provide a floating image display system for vehicles that can display so-called one-way floating images that are visible from outside the vehicle, for example, through shield glass including the windshield, rear window, and side windows of the vehicle.

[0017] As shown in Figure 1A, the retroreflective member 5 used in the floating image display device comprises a first optical control panel 221 (also referred to as the first optical control member) and a second optical control panel 222 (also referred to as the second optical control member). The first optical control panel 221 and the second optical control panel 222 are each formed by arranging numerous strip-shaped planar light-reflecting members 20 at a constant pitch perpendicular to one side surface of a transparent flat plate 18, 17 of constant thickness. The optical members 20 are light-reflecting members. Here, the light-reflecting members 20 constituting the first optical control panel 221 and the second optical control panel 222 intersect in a plan view of the main surface of the retroreflective member 5, and are arranged orthogonally in this embodiment.

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

[0019] The mechanism of image formation of the floating image 3 will be explained in detail below using Figures 1A to 2B. Figure 2A is a perspective view of the retroreflective member 5 shown in Figure 1A. Figure 2B shows the configuration of the main surface of the retroreflective member 5 in plan view. In Figure 2A, the image light from the image display device 1 is incident on the transparent plate 18 as one side of the retroreflective member 5, reflected through the light-reflecting portion of the optical member 20 of the first light control panel 221 and the light-reflecting portion of the optical member 20 of the second light control panel 222, and exits from the transparent plate 17 as the other side. In the plan view of Figure 2B, the light-reflecting portion is formed in a grid pattern by the intersection of the optical member 20 of the first light control panel 221 and the optical member 20 of the second light control panel 222.

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

[0021] As described above, the retroreflective member 5 has two reflective surfaces, and as shown in Figures 2A and 2B, in addition to the floating image 3 formed by normal reflected light, two ghost images 3a and 3b are generated depending on the number of reflective surfaces. The reflected light emitted from the retroreflective member 5 has normal reflected light that forms the normal image of the floating image 3 and abnormal reflected light that forms the ghost images 3a and 3b.

[0022] Furthermore, when ambient light intensity is high and incident from the upper surface of the retroreflective member 5, the spacing between the reflective surfaces (e.g., 300 μm or less) becomes shorter, causing optical interference. This results in the observation of rainbow-colored reflected light, which has the drawback of making the presence of the retroreflective member 5 apparent to the observer. Therefore, to prevent interference light generated by the pitch of the reflective surfaces of the retroreflective member 5 from returning to the observer's eye due to ambient light incidence, the area over which interference light is generated was experimentally determined using the measurement environment shown in Figure 3A, with the incident angle of ambient light as a parameter. The results obtained are shown in Figure 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, and the retroreflective member 5 is tilted to an inclination angle θYZ of 35 degrees or more, the interference light does not return to the observer.

[0023] On the other hand, it was found that with the ratio H / P of the pitch P of the light-reflecting member 20 to the height H of the reflective surface, approximately 60% of the reflective surface formed a floating image due to retroreflection, while the remaining 40% became anomalous reflected light that generated ghost images. In order to improve the resolution of floating images in the future, it is essential to shorten the pitch of the reflective surface. In addition, in order to suppress the generation of ghost images, the height of the reflective surface needs to be higher than it is currently. Due to manufacturing constraints of the retroreflective member 5, the ratio H / P of the pitch P to the height H of the reflective surface should be selected in the range of 0.8 to 1.2, compared to the current value of 1.0.

[0024] Based on the above considerations, the inventors have investigated a retroreflective optical system that can improve the image quality of floating images obtained in a floating image display system using a retroreflective material that inherently produces less ghosting. This will be explained in detail below with reference to the drawings.

[0025] <Example of the configuration of the first retroreflective optical system> Figures 4A and 4B show examples of configurations relating to the image display device 1 and retroreflective member 5 that constitute the first retroreflective optical system used to realize a floating image display system. In the following description of the embodiments, the liquid crystal panel 11 is referred to as "liquid crystal panel," but it may also be referred to as "liquid crystal display panel," "display panel," or "image display element."

[0026] In the retroreflective optical system shown in Figure 1B above, the floating image 3 is formed symmetrically with respect to the retroreflective member 5 and the image display device 1. Therefore, the angles θ1 and θ2 formed in each arrangement are approximately equal. For this reason, if the angle at which the viewer's eye looks at the floating image 3 of the floating image display system is determined, the angle θ2 between the image display device 1 and the retroreflective member 5 in the retroreflective optical system should be set to, for example, half the angle at which the floating image 3 is viewed.

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

[0028] The spatial levitation image display device of the embodiment comprises an image display device 1 that emits image light of a specific polarization at a narrow angle, and a retroreflective member 5 that retroreflects the image light emitted from the image display device 1 at a narrow angle. The retroreflected light from the retroreflective member 5 forms a spatial levitation image 3 that has directionality in a specific direction. As shown in Figure 4A, etc., the image display device 1 comprises 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, it is preferable that an absorbing polarizing sheet with an anti-reflective coating be provided on the outer surface of the retroreflective member 5 facing the floating image 3. The absorbing polarizing sheet selectively transmits image light of a specific polarization for forming the floating image 3, while absorbing other polarizations contained in the ambient light. This prevents the influence of reflected light from the surface of the retroreflective member 5 on the floating image 3.

[0030] Furthermore, 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, unlike the diffused image light formed on a screen by a typical projector, the floating image 3 is an image with high directivity.

[0031] Therefore, as shown in Figure 1B, when viewed from the direction of the viewer's eyes, the floating image 3 is visible as a bright image. However, when viewed from other directions, for example, by another person viewing from the opposite direction from the viewer's eyes, the floating image 3 is not visible at all. This characteristic is highly suitable for use in systems that display images requiring high security or highly confidential images that should be concealed from people directly facing the user.

[0032] Furthermore, depending on the performance of the retroreflective member 5, the polarization axes 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 absorption-type polarizing sheet described above. Therefore, unwanted reflected light is not generated in the retroreflective optical system, and a decrease in the image quality of the floating image 3 can be prevented or suppressed.

[0033] Furthermore, in the floating image display device of the embodiment, when a viewer looks into the floating image 3, the display screen of the image display device 1 itself is shielded from light by the reflective surface of the retroreflective member 5, making the image on the display screen of the image display device 1 difficult to see and not hindering the viewing of the floating image 3.

[0034] The liquid crystal panel 11 shown in Figure 4A can be applied to a range of screen sizes, from small ones of about 5 inches to large ones exceeding 80 inches, and can be selected according to the system implementation.

[0035] To eliminate ghost images corresponding to abnormally reflected light shown in Figure 2A, etc., and obtain a high-quality floating image 3, a video light control sheet may be provided on the output surface side of the liquid crystal panel 11 to control the diffusion characteristics in unwanted directions. Alternatively, a video light control sheet may also be provided on the video output surface of the retroreflective member 5 to eliminate ghost images that occur on both sides of the normal image of the floating image 3.

[0036] The image light from the liquid crystal panel 11 is preferably polarized as S-polarization, for example, because this allows for a higher reflectivity in the retroreflective member 5 in principle. S-polarization is polarization perpendicular to the incident plane, and P-polarization is polarization parallel to the incident plane. When the viewer uses polarized sunglasses, the light forming the floating image 3 is reflected or absorbed by the polarized sunglasses. As a countermeasure in this case, a depolarization element may be provided, which is an element that optically converts a portion of the image light of the specific polarization from the liquid crystal panel 11 to the other polarization, thereby simulating natural light. In this case, the viewer can still view a good floating image 3 even when using polarized sunglasses.

[0037] When an absorbing 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 the components 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 for reducing ghost images> Using Figure 4A and the like, technical means for realizing a high-quality spatial image display device that reduces the aforementioned ghost image will be explained. Figures 4A and 4B show specific technical means for applying an image light control sheet to a spatial image display device. As shown in Figure 4A, in order to control the divergence angle of image light from the liquid crystal panel 11, which is an image display element, an image light control sheet 334A may be provided on the emission surface of the liquid crystal panel 11. Furthermore, as shown in Figure 4B, by providing the light emission surface or the light incidence surface or both sides thereof of the retroreflective member 5, abnormal light that generates ghost images may be absorbed.

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

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

[0041] In Figure 4A, two methods are effective in reducing moiré patterns caused by interference between the pixels of the liquid crystal panel 11 and the light-transmitting portion 336 and light-absorbing portion 337 of the image light control sheet 334A, depending on the pitch.

[0042] In the first method, the vertical stripes generated by the light-transmitting portion 336 and the light-absorbing portion 337 of the image light control sheet 334A are positioned at a predetermined angle relative to the pixel arrangement of the liquid crystal panel 11.

[0043] The second method involves selecting a ratio B / A that is not an integer multiple, where A is the pixel dimension of the liquid crystal panel 11 and B is the pitch of the vertical stripes on the image light control sheet 334A.

[0044] Each pixel of the liquid crystal panel 11 is composed of three subpixels of RGB colors arranged in parallel, and is generally square; therefore, it is not possible to completely suppress the occurrence of moiré patterns across the entire screen. For this reason, experimental results have shown that 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 moiré patterns occur can be intentionally shifted to areas where the floating spatial image 3 is not displayed.

[0045] Regarding the reduction of moiré patterns, we have described it using the liquid crystal panel 11 as an example. In Figure 4B, the moiré patterns that occur between the retroreflective member 5 and the image light control sheet 334B can be reduced as follows. Since both the retroreflective member 5 and the image light control sheet 334B are linear structures, the image light control sheet 334B is tilted optimally with respect to the X-axis. In Figure 4B, the vertical stripes formed by the transmissive portion 336 and the light-absorbing portion 337 of the image light control sheet 334B are inclined at an angle θX with respect to the perpendicular direction of the surface, in line with the direction of emission of retroreflective light. This reduces large moiré patterns with long wavelengths and low frequencies that are visible to the naked eye. Furthermore, this absorbs the abnormal light generated by the retroreflection mentioned above, while transmitting normal reflected light without loss.

[0046] Furthermore, if, for example, a 7-inch WUXGA (1920 x 1200 pixels) liquid crystal panel is used as the liquid crystal panel 11, which is 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, if, for example, the width d2 of the transparent portion 336 of the image light control sheet 334A in Figure 4A is 300 μm and the width d1 of the light absorbing portion 337 is 40 μm, and the pitch B is 340 μm, sufficient transmission characteristics can be achieved. In this case, the diffusion characteristics of the image light from the image display device 1, which are the cause of abnormal light generation, can be controlled, and ghost images that occur on both sides of the normal image of the floating image 3 can be reduced. At this time, if the thickness of the image light control sheet 334A is 2 / 3 or more of the pitch B, the ghost reduction effect will be greatly improved.

[0047] On the other hand, the aforementioned video light control sheets 334A and 334B also prevent external light from entering the interior of the floating video display device, thus contributing to improved reliability of the components. For example, Shin-Etsu Polymer Co., Ltd.'s viewing angle control film (VCF) is suitable as this video light control sheet. The structure of the VCF consists of alternating transparent and black silicone layers with synthetic resin placed on the light input and output surfaces, creating a sandwich structure. Therefore, the VCF as a video light control sheet can be expected to have the same effect as an external light control film.

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

[0049] In the examples in Figures 5A and 5B, angle α represents an angle of approximately 45 degrees diagonally downward with respect to the Y direction, which corresponds to viewing the floating image 3 directly from a direction perpendicular to the plane. Similarly, a suitable angle is assumed for when the floating image 3 is operated by the user's finger UH by touch, etc., and this angle is also assumed to be the same as angle α. An example of implementation of the floating image display system will be described later, but a so-called kiosk terminal is one example. The kiosk terminal has a housing 501 of a predetermined shape.

[0050] The arrangement of the floating image 3 is determined according to the selection of such viewing angle α. In that case, the arrangement of the components of the floating image display device, such as the retroreflective member 5 and the image display device 1, is determined in accordance with the arrangement of the floating image 3.

[0051] The example in Figure 5A shows an example in which the retroreflective member 5 is positioned to align with the front surface 501a of the system housing 501 so that the plane of the floating image 3 protrudes forward relative to the front surface 501a of the housing 501, in other words, floats. Furthermore, the example in Figure 5A shows the case in which the floating image 3 is positioned at the angle θ1 shown in the figure, such that the distance LA protruding from the upper side is greater than that from the lower side, relative to the front surface 501a of the housing 501 and the retroreflective member 5. The floating image 3 is positioned to form an angle θ1 with respect to the retroreflective member 5 and the front surface 501a of the housing 501. The liquid crystal panel 11 of the video display device 1 is positioned to form an angle θ2 with respect to the retroreflective member 5 and the front surface 501a of the housing 501.

[0052] On the other hand, the example in Figure 5B shows the case where the floating image 3 is positioned at the angle θ1 shown in the figure, such that the distance LB protrudes greater from the lower edge than from the upper 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 positioned at an angle θ1 with respect 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 with respect to the retroreflective member 5 and the front surface 501a of the housing 501. Here, angles θ1 and θ2 are approximately the same or identical, and are smaller angles than angles θ1 and θ2 in Figure 1B, being less than 40 degrees.

[0053] In Figures 5A and 5B, angles θ1 and θ2 are approximately the same or identical, and both are smaller angles than those in Figure 1B, for example, less than 45 degrees. Also, in Figure 5B, the distance between the lower end of the retroreflective member 5 and the lower end of the image display device 1 is about the same as the distance LB between the lower end of the retroreflective member 5 and the lower end of the floating image 3. The floating image 3 and other methods including angle α in Figure 5B are suitable when the height of the viewer's eye UE, which is assumed to be the reference point, is relatively high.

[0054] The floating video display device has a cover 502 that houses its components, such as the video display device 1 and the retroreflective member 5, and is shown with a dashed frame in Figures 5A and 5B. It is desirable that the floating video display device, including the cover 502, be housed within the system's housing 501. The video display device 1 and the retroreflective member 5 are fixed within the cover 502 in a predetermined positional relationship, as shown in the figures.

[0055] The image display device 1 comprises a liquid crystal panel 11 and a light source assembly 30, which is a light source device 13. The light source assembly 30 comprises an LED, a reflector, a polarization conversion element, a light guide, a diffuser, etc., which are light sources described later. The liquid crystal panel 11 is fixed to the light source assembly 30.

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

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

[0058] Here, the thinning of the system in the aforementioned problem means, for example, that the dimensions of the housing 501 are small in the Y direction, which is the depth direction. The thinning of the floating image display device means, for example, that the dimensions of the cover 502 are small in the Y direction, which is the depth direction. In order to accommodate the thinning of the system, the cover 502 of the floating image display device is also required to have a compact configuration, including small dimensions of the cover 502 in the Y direction, so that it can be housed inside the housing 501.

[0059] Furthermore, the LCD panel 11 is connected to flexible cables for driving, relay boards, and video signal processing boards. A power supply board is also required to supply power to the light source assembly 30 and other components. It is desirable that these components be arranged so as to be housed within the cover 502 or housing 501. This aspect will be discussed later.

[0060] For explanatory purposes, the method of the floating image 3 and floating image display device shown in Figure 5A will be referred to as the top-edge projection method, and the method shown in Figure 5B will also be referred to as the bottom-edge projection method. In the embodiments described later, the method shown in Figure 5B will be shown to optimize the system. When the method in Figure 5A is adopted, as shown in the figure, if a suitable angle α is prioritized, the dimensions in the depth direction become larger in terms of the arrangement and shape of the housing 501 and cover 502. Also, in the method in Figure 5A, if the angle of the front surface 501a, which is the slope of the housing 501, is to be tilted closer to vertical as in Figure 5B, the angle of the arrangement of the floating image 3 will also be tilted closer to vertical. Therefore, in that case, it may be difficult to see and operate.

[0061] In contrast, the method shown in Figure 5B allows for a smaller depth dimension in terms of the arrangement and shape of the housing 501 and cover 502 compared to the method shown in Figure 5A. In the case of Figure 5B, the system can be optimized considering the thinning of the system and device, the reduction of the thermal effects of the light source assembly 30, and also the ease of viewing and operating the floating image 3, as well as the ease of system implementation.

[0062] In one embodiment, the floating image display system is configured to incorporate a floating image display device, as shown in Figure 5B above, on top of a kiosk terminal, for example. As described above, the position and angle of the retroreflective member 5 and the image display device 1 of the floating image display device are optimally designed so that the floating image 3 can be viewed favorably from the position of the assumed viewer's eyes UE at a desired angle α. In the floating image 3 displayed by the floating image display device on top of this kiosk terminal, an image of an avatar guiding the user through the service is displayed. In this case, the image light of the floating image 3 is directed towards the viewer's eyes at a suitable angle α, and the viewer can view the high-brightness floating image 3 at the suitable angle α. Furthermore, the viewer can operate the floating image 3 at the suitable angle α.

[0063] <Airborne Sensor> This section describes an aerial sensor 50 as a sensing technology for controlling the floating image 3 displayed by the floating image display device, as an operator. For example, an example of the configuration of the aerial sensor 50 that can be applied in the configuration shown in Figure 5B is described. The aerial sensor 50 is positioned on the plane on which the floating image 3 is placed, at a distance from the top edge of the floating image 3. More specifically, the aerial sensor 50 may be positioned so as to be hidden behind the components that make up the front surface 501a of the housing 501.

[0064] The aerial sensor 50 is comprised of a sensor device and a detection circuit. The aerial sensor 50 can be implemented, for example, using a distance measuring device incorporating AirBar®. Figure 6 shows an example configuration of the aerial sensor 50, with the configuration shown in the xy plane as the plane on which the floating spatial image 3 is placed.

[0065] The aerial sensor 50 has, on a long plate-shaped substrate 50A, a light-emitting unit 50a and a light-receiving unit 50b as sensor devices in each row corresponding to the y-direction lines of the floating spatial image 3, and multiple such units are arranged alternately along the x-direction. 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 downwards in the y-direction in synchronization with the system signal. An optical element for controlling the divergence angle is arranged on the emission side of the LED of the light-emitting unit 50a, although it is not shown.

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

[0067] In the xy plane of the floating image 3, when a finger UH is positioned at a certain pixel position GP through 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 airborne sensor 50 can detect the pixel position and movement when an operation such as touching is performed in the air on the plane of the floating image 3 by a 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 perpendicular to the xy-plane of the floating spatial image 3. In this case, the position and movement of the finger UH, such as its entry into the plane of the floating spatial image 3 in the z-direction, can also be detected.

[0069] The sensor device of the aerial sensor 50 in Figure 6 is positioned in the xy plane at a predetermined distance from the upper edge 3U of the floating spatial image 3.

[0070] In Figure 5B, the distance between the upper edge of the floating image 3 and the front surface 501a of the housing 501 is shorter than the protrusion distance LB on the lower edge side, but this distance is also sufficiently maintained. 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; a ranging device with a built-in TOF (Time of Flight) system may also be used.

[0071] [Liquid crystal panel and light source assembly] Figures 7A and 7B show examples of configurations of a liquid crystal panel 11 and a light source assembly 30 applied to a floating image display system and a floating image display device, and also serve as schematic diagrams illustrating the issues related to the thermal effects of the light source assembly 30 on the flexible cable 703 of the liquid crystal panel 11. The issues will be explained using Figures 7A and 7B. Figure 7A illustrates the case where the liquid crystal panel 11 of the image display device 1 of the floating image display device is arranged in the horizontal direction in Figure 7A. The horizontal direction in Figure 7A is, for example, the horizontal plane, but is not limited to that here. Figure 7B shows the flexible cable and various substrates connected to the main body of the liquid crystal panel 11 when the display screen 11a of the liquid crystal panel 11 is viewed from above.

[0072] Depending on the implementation of the floating image display system, the size of the display screen 11a of the liquid crystal panel 11 is ensured to be a predetermined size. In this case, in the configuration example shown in Figure 7A, the light source assembly 30 is composed of a light source assembly 30A and a light source assembly 30B in order to ensure that size. In the horizontal direction of Figure 7A, the light source assembly 30 consists of two light source assemblies, 30A and 30B, arranged symmetrically with respect to the center line C. 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, LEDs, a reflector, a heat sink, etc., and the light guide section 32A includes a light guide, which will be described in more detail later.

[0073] In Figure 7B, one end of a flexible cable 701 is connected to the main body of the liquid crystal panel 11, for example, on the lower edge 11D side, and the other end of the flexible cable 701 is connected to a relay board 702. One end of a flexible cable 703 is connected to the other end of the relay board 702. The other end of the flexible cable 703 is connected to a video signal processing board 704. The spatial area where the light source units 31A and 31B are located is shown with a dashed frame. For example, the areas of the light source units 31A and 31B are located in the area above the upper edge 11U and the area below the lower edge 11D relative to the display screen 11a area 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] The light source assembly 30, flexible cable 703, and various circuit boards are housed in a cover 502, for example, as shown in Figure 5B. In Figure 5B, the upper space 5001 inside the housing 501 is narrower than the lower space 5002, making it unfavorable to place the flexible cable and the like in the upper space 5001. Therefore, in this embodiment, the flexible cable 703 and the like, which are pulled out from the lower edge 11D side of the liquid crystal panel 11, are considered to be placed and housed in the lower space 5002 inside the housing 501 in Figure 5B.

[0075] In the lower space 5002 within the enclosure 501, the available space for accommodation, including the depth dimension, is limited, and it is necessary to keep the volume of the cover 502 as small as possible. If the flexible cable 703 and other components are to be placed with ample space in the lower space 5002, the cover 502 will become larger, making it difficult to accommodate it inside the enclosure 501. Therefore, the flexible cable 703 and relay board 702 are compactly housed within a cover 502 that has a reduced volume to match the dimensions of the enclosure 501, including the depth dimension.

[0076] However, when housing the light source assembly 30, flexible cable 703, etc., within the cover 502, which has a reduced volume, it becomes necessary to position the flexible cable 703, relay board 702, etc., in close contact with or near the light source assembly 30.

[0077] Figure 8 shows a comparative example where a compact configuration prioritizing a reduced thickness of the cover 502 is prioritized, and the flexible cable 703 and substrate are arranged inside the cover 502 in close proximity to the light source unit 31 of the light source assembly 30. Figure 8 shows only the portion corresponding to one of the light source assemblies 30A. The space between the liquid crystal panel 11 and the retroreflective member 5 becomes the optical path for the image light, so the flexible cable and other components are not placed on that side. In this comparative example, the flexible cable 703 and other components are arranged to wrap around to the back of the light source assembly 30A via the side of the light source unit 31A. In this comparative example, in the direction shown in Figure 8, the flexible cable 701 and relay substrate 702 are arranged above the light source unit 31A, the flexible cable 702 is arranged in close proximity to the left side of the light source unit 31A, and the video signal processing substrate 704 is arranged in close proximity to the bottom of the light source unit 31A. The cover 502 is configured to accommodate these components.

[0078] However, in such comparative examples, heat-sensitive components such as the flexible cable 703 are placed in close proximity to the light source unit 31A, making them susceptible to the heat generated from the light source, reflector, and heat sink of the light source unit 31A. This may lead to deterioration or damage to the flexible cable 703 and other components.

[0079] Furthermore, as shown in Figure 8, if the liquid crystal panel 11 and the light source assembly 30A are arranged on a horizontal plane, thermodynamically, heat from the light source 31A flows vertically from bottom to top, making the flexible cable 703 and the relay board 702 susceptible to the effects of that heat.

[0080] Therefore, in this embodiment, the light source assembly 30, flexible cable 703, relay board 702, etc., are housed within a cover 502 with reduced volume, and a configuration has been devised that takes into account both a compact structure and the reduction of the effects of heat on the light source. Details are described below.

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

[0082] The flexible cable 703 is arranged in a curved manner so as to wrap around from the relay board 702, which is located on the front side of the light source unit 31A in the Y-axis direction, through the lower part of the Z-axis direction, to the video signal processing board 704, which is located on the rear side of the Y-axis direction. In this wrapping motion, the flexible cable 703 is arranged at a predetermined distance 1001 in the Z-direction so as not to come into close proximity with the light source unit 31A. The flexible cable 703 is arranged with a distance of 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 of 1001 is secured by utilizing the space 5001 at the bottom of the housing 501. The distance 1001 is designed according to the implementation of the system and device, but is at least 1 cm. The distance 1001 is shown as the distance from the end face of the light source unit 31A, but as will be described later, it may be the distance from the light source LED, or from the substrate, heat sink, or reflector.

[0084] In this embodiment, heat-sensitive components such as the flexible cable 703 are positioned sufficiently far from the light source unit 31A, so these components are less affected by the heat emitted from the light source, reflector, and heat sink of the light source unit 31A. Therefore, deterioration and damage to the flexible cable 703 and other components can be prevented.

[0085] Furthermore, as shown in Figure 9, when the liquid crystal panel 11 and the light source assembly 30A are arranged vertically, thermodynamically, heat from the light source 31A flows vertically from bottom to top. Therefore, the flexible cable 703, which is positioned below the light source 31A, is less affected by that heat.

[0086] Furthermore, Figure 9 also shows an example of the arrangement of the power supply board 705 that supplies power to the light source unit 31A, etc. The power supply board 705 is located on the back side of the light source assembly 30 in the Y-axis direction. The power supply board 705 also generates heat, but this heat flows upward in the vertical direction. The flexible cable 703, which is located below the power supply board 705, is less affected by this heat.

[0087] The flexible cable 701 and the relay board 702 are positioned on the front side in the Y-axis direction relative to the light source unit 31A, but the light sources and other components within the light source unit 31A are positioned towards the rear and back sides in the Y-axis direction, so heat from the light sources and other components flows upward. Therefore, the flexible cable 701 and the relay board 702 are less affected by the heat from the light sources and other components within the light source unit 31A.

[0088] The video signal processing board 704 is positioned on the rear side in the Y-axis direction relative to the light source unit 31A. Although the processor and other components on the video signal processing board 704 also generate heat, a heat sink is provided for these components, allowing the heat to flow upwards. Therefore, the video signal processing board 704 is less affected by heat from the light source and other components within the light source unit 31A.

[0089] <Spatial floating image display device of Embodiment 1> Using Figures 10 onward, the details of the floating image display device of Embodiment 1 and the floating image display system comprising the floating image display device will be described. Below, as an example of implementation of the floating image display system, we will describe its application to kiosk terminals installed in train stations, convenience stores, etc. However, it is not limited to this, and the floating image display system can be applied to various systems, such as ATMs (automated teller machines) and automatic ticket vending machines. 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 floating image 3. An example of an angle is angle α in Figure 5B mentioned above. The floating image display device is implemented in the system according to these requirements.

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

[0091] Figure 11 shows a cross-sectional view of the YZ plane of the floating image display device of Embodiment 1, and the cover 502 and light source assembly 30 are only schematically shown in outline. The area around the light source unit 31A and the flexible cable 703 in Figure 11 has the same configuration as in Figure 9.

[0092] The video signal processing board 704 receives control signals from the system's control device and video signals from the video source via a predetermined communication interface through a connector, and performs video signal processing for displaying images on the liquid crystal panel 11, which is an image display device. The video signal processing board 704 then transmits the display signals generated as a result of this processing to the relay board 702 via the flexible cable 703 through the connector.

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

[0094] The power supply board 705 is located on the back 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 section 31 (31A, 31B) of the light source assembly 30, as shown in Figure 7A. The power supply circuit of the power supply board 705 is connected to the board of the light source section 31 via a power cable from a connector, although this is not shown.

[0095] Figure 12 is a perspective view of the floating video display device shown in Figure 10 with the cover 502 attached, omitting the video display device 1 and other components. An example of the detailed configuration of the cover 502 is the presence of cover 502a, cover 502b, cover 502c, etc. Cover 502a houses and secures the liquid crystal panel 11, light source assembly 30, flexible cable 703, etc., of the video display device 1. Cover 502b secures the retroreflective member 5, for example, on all four sides. Cover 502c is a support member extending from cover 502a, supporting and securing the aerial sensor 50.

[0096] Figure 13 shows a perspective view of the spatially floating image display device shown in Figure 12 without the cover 502, and shows the light source assembly 30, relay board 702, etc. of the image display device 1.

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

[0098] Figure 15 shows an XY plan view of the spatial levitation image display device shown in Figure 12, without the cover 502, viewed from the rear side in the Z-axis direction. On the rear side of the light source assembly 30, the video signal processing board 704 is located on the lower side in the Z-axis direction. The video signal processing board 704 includes a processor, a connector 704b for the flexible cable 703, and a heat sink 704c, etc. A power supply board 705 is located near the center of the light source assembly 30 in the Z-axis direction. In this example, there are three power supply boards 705, arranged in the X-axis direction.

[0099] Figure 16 shows a YZ plan view of the spatially floating image display device shown in Figure 12 with the cover 502 attached, viewed from the side in the X-axis direction. In addition to the parts described above, the cover 502 also has a cover 502e and a cover 502g. The cover 502e covers the part of the image display device 1 that includes the liquid crystal panel 11 and the light source assembly 30 from both sides in the X-axis direction. The part of the cover 502e that is located below in the Z-axis direction, the cover 502f, covers the aforementioned flexible cable 703, etc., in the Z-axis and X-axis directions.

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

[0101] Cover 502g extends from cover 502e towards the front in the Y-axis direction and supports and fixes the retroreflective member 5.

[0102] Figure 17 shows a YZ cross-sectional view of the spatially floating image display device of Figure 12 without the cover 502, viewed from the side in the X-axis direction, and shows a detailed structural example corresponding to Figure 11. The image display device 1 has a light source assembly 30, which consists of two sets of lower light source assemblies 30A and upper light source assemblies 30B, arranged vertically symmetrically in the Z-axis direction with respect to the center line C, similar to Figure 7A. For example, the lower light source assembly 30A has a light source section 31A positioned below in the Z-axis direction, and a light guide section 32A positioned above the light source section 31A and below the center line C. The light source assembly 30A emits light upward in the Z-axis direction from the light source section 31A, and reflects that light forward in the Y-axis direction by the light guide section 32A. The light source assembly 30B emits light downward in the Z-axis direction from the light source section 31B, and reflects that light forward in the Y-axis direction by the light guide section 32B. A diffuser plate 204 is positioned between the light guide units 32A and 32B and the liquid crystal panel 11.

[0103] The light source units 31A and 31B extend long in the X-axis direction, and multiple light sources and reflectors 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, and a heat sink 330 is positioned on the back side in the Y-axis direction relative to the substrate on which the LED is mounted. The heat sink 330 is a heat sink for the LED. The light source unit 31A reflects the divergent light from the LED upwards along the Z-axis as nearly parallel light using a reflector. This parallel light upwards along the Z-axis is polarized through a polarization conversion element (described later) and then incident on the light guide unit 32A. This 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 plate 204, and incident on the back side of the liquid crystal panel 11. The same action is observed in the light source assembly 30B, but with the action reversed vertically.

[0104] In Figure 17, the cover 502 is shown with a dashed line; further details are shown in Figures 12, 14, and 16. 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, which are drawn out from the lower edge of the liquid crystal panel 11, are arranged to wrap around to the back side of the light source assembly 30A, taking a detour through a space 1002 that includes a distance 1001 from the light source unit 31A, as explained in Figure 9.

[0106] Figure 18 is a perspective view of the light source unit 31A and flexible cable 703 of the video display device 1 of the floating video display device shown in Figure 12, viewed from the lower side of the liquid crystal panel 11 and the back side of the light source assembly 30. Similarly, Figure 19 is a perspective view of the light source unit 31B and other components of the video display device 1, viewed from the upper side of the liquid crystal panel 11 and the back side of the light source assembly 30. The light source units 31A and 31B extend in the X-axis direction corresponding to the lower and upper sides of the liquid crystal panel 11, and a heat sink 330 is located on the back side in the Y-axis direction. In this example, the heat sink 330 is provided not only in the part that is in contact with the back of the LED substrate, but also in the part that is facing outward in the Z-axis direction. As shown in Figures 7A and 10, the flexible cable 701 etc. is pulled out from the lower side of the liquid crystal panel 11, for example near the center in the X-axis direction, and as shown in Figure 18, the flexible cable 703 is arranged to wrap around one side of the light source unit 31A on the lower Z-axis side.

[0107] In addition, the basic configuration assumes that nothing other than air is provided in the space 1002 between the light source unit 31A and the flexible cable 703, etc., as shown in Figure 17. As a variation, components for fixing the flexible cable 703, etc., to a predetermined suitable position may be provided within this space 1002. In this case, the component may be a part of the cover 502, for example, a component that protrudes inward from the cover 502f in Figure 16.

[0108] According to the floating image display device of Embodiment 1 described above, it is possible to make the floating image display system and the floating image display device thinner and more compact, reduce the effects of heat on the light source assembly 30 and other components, and minimize the effects of degradation on heat-sensitive components such as the flexible cable 703.

[0109] As described above, the floating image display device of Embodiment 1 shown in Figures 10 to 19 achieves a compact configuration with the depth dimension minimized, and reduces the thermal impact of the light source unit 31A and power supply board 705 on heat-sensitive flexible cables 703, etc. Furthermore, this floating image display device is easily mounted on a housing 501 of a floating image display system as shown in Figure 5B, enabling user-friendly viewing and operation of the floating image 3.

[0110] In the first embodiment described above, the spatially floating image display device is configured to provide a space 1002 as shown in the figure for routing flexible cables 703 and the like from the liquid crystal panel 11 to the video signal processing board 704, thereby reducing the impact of heat from the LEDs and heat sink of the light source device 13 on the flexible cables 703 and the like. These flexible cables 703 and the like can be made of components with specified dimensions such as length, and are supported or covered by a cover 502, in other words, a case or support member.

[0111] Furthermore, in the spatial floating image display device of Embodiment 1 described above, as shown in Figures 5B and 11, the image display device 1 is roughly positioned vertically in accordance with the lower edge protrusion method as a retroreflective optical system design. Then, space for routing the flexible cable 703, etc., is provided on the lower side of the liquid crystal panel 11, where the gap between the retroreflective member 5 and the image display device 1 (a distance similar to the distance LB in Figure 5B) is larger. The space on the upper side of the liquid crystal panel 11 is narrower than the space on the lower side and is disadvantageous in terms of routing and heat, so space for routing is provided on the lower side. In the space on the lower side, the flexible cable 703 is positioned at the very bottom, excluding the cover 502f. With this arrangement, the heat from the light source part 31A of the light source assembly escapes vertically from bottom to top, so the flexible cable 703, etc., is less affected by that heat.

[0112] Furthermore, in the spatial floating image display device of Embodiment 1 described above, as shown in Figure 17, the video signal processing board 704 and the power supply board 705 are arranged such that the video signal processing board 704 is on the lower side and the power supply board 705 is on the upper side in the vertical direction. The video signal processing board 704, which can be connected to the flexible cable 703 located in the space on the lower side, is placed near the flexible cable 703 and on the back side of the light source assembly. Since the flexible cable 703 and the video signal processing board 704 are positioned below the power supply board 705, they are less affected by the heat generated by the power supply board 705.

[0113] Furthermore, the floating image display device of Embodiment 1 described above, as shown in Figure 5B and other figures, is arranged in a lower-side projection manner, taking into consideration the implementation of the system. The aerial sensor 50 is positioned on the upper side relative to the liquid crystal panel 11, where the distance between the retroreflective member 5 and the image display device 1, in other words, the projection distance of the floating 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 cover 502 containing the aerial sensor 50 and support member, can be made compact and thin.

[0114] <Example of a kiosk terminal configuration> Next, using Figures 20 and onward, an example of a kiosk terminal configuration will be described as an implementation example of a spatial floating image display system that includes the spatial floating image display device of Embodiment 1 described above.

[0115] A kiosk terminal is an information terminal that has traditionally allowed a large number of people to access necessary information and use various services through a human-machine interface or user interface, such as a touch panel. Kiosks are installed in public facilities, transportation facilities, entertainment facilities such as amusement parks, and in recent years, also in convenience stores. Kiosks are used for selling various types of tickets and for administrative services, such as issuing resident registration certificates.

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

[0117] First, Figure 20 shows a perspective view of a typical kiosk terminal 2000 configuration for comparison. This kiosk terminal 2000 is equipped with a metal casing 501, for example, with a height of 120-150 cm. The height of the casing 501 is determined considering the user's height. On the front surface 501a of the casing 501, which is the slanted surface facing the user, a liquid crystal display screen 2001 and input buttons 2002 are provided. The liquid crystal display screen 2001 is part of a liquid crystal display device and is a touch panel screen that displays various information and accepts touch operations from the user. The input buttons 2002 are physical buttons for entering a unique PIN or the like, or touch buttons on a screen configured as a touch panel. In addition, a dispensing opening 2003 is provided in a part of the area near the front surface 501a of the casing 501. The dispensing opening 2003 is for dispensing items such as issued tickets or administrative documents as a result of operations on the kiosk terminal 2000.

[0118] Figure 21 shows a perspective view from the upper right as an example of the external configuration of a kiosk terminal 2100 equipped with the spatial floating image display device of Embodiment 1 as shown in Figures 10 to 19. Figure 21 shows a first configuration example of the kiosk terminal. The housing 501 in Figure 21 has a substantially similar configuration to the housing 501 in Figure 5B, with dimensions in the depth direction being specified. The housing 501 has an outlet 2003 and the like in the lower part, which was omitted from the illustration in Figure 5B, and also has a human presence sensor 2106, for example, located near the ground. The control device, communication device, power supply device, etc. that constitute the kiosk terminal 2100 are housed inside the lower part of the housing 501.

[0119] The kiosk terminal 2100 in Figure 21 differs from the kiosk terminal 2000 in Figure 20 in the following ways. The kiosk terminal 2100 in Figure 21 has a liquid crystal display screen 2101 at the top of the front surface 501a of the housing 501, similar to Figure 20, and in addition, a floating-space image display unit 2102 at the bottom for displaying floating-space images 3. This floating-space image display unit 2102 is composed of the floating-space image display device of Embodiment 1. In other words, the kiosk terminal 2100 has two screens with two types of images, the liquid crystal display screen 2101 and the floating-space image display unit 2102, and has a configuration in which the front surface 501a is divided into two display units, the liquid crystal display screen 2101 and the floating-space image display unit 2102.

[0120] In the configuration example shown in Figure 21, of the two screens, the screen of the floating spatial image display unit 2102 is used as the primary screen. This screen will also be referred to as the first screen. On this first screen, images from the floating spatial image 3 are displayed as the user interface. Examples of images include avatars and operation menus. Figure 21 shows an example where the floating spatial image 3 displays an avatar 2105 (in other words, a person, a concierge) that guides users through services, etc., on the first screen.

[0121] The first screen of the floating image display unit 2102 is based on an area of ​​predetermined size in both vertical and horizontal dimensions. In this example, the first screen has a slightly wider horizontal 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, similar to a typical kiosk terminal. The liquid crystal display screen 2101 will also be 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 in conjunction with the first screen of the floating image display unit 2102 as a user interface such as an operation menu.

[0124] Furthermore, as a variation, a configuration is also possible in which the second screen, which is the liquid crystal display screen 2101, is not provided.

[0125] As another variation, the first screen of the floating-space image display unit 2102 in Figure 21 may display both the avatar and the operation menu as a single floating-space image 3. However, since the size of the first screen is limited, displaying both on the first screen may result in small, detailed content that is difficult to see. Therefore, in the example in Figure 21, the display switching is controlled so that either the avatar or 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 floating image display unit 2102, is not limited to the configuration example shown in Figure 21. For example, the vertical arrangement of these two screens may be reversed. Also, the two screens may be arranged side by side on the front surface 501a. However, in a configuration where the kiosk terminal 2100 includes both the liquid crystal display screen 2101 and the floating image display unit 2102, it is more preferable to arrange the components within the housing 501 with the liquid crystal display screen 2101 on the upper side and the floating image display unit 2102 on the lower side, as shown in Figure 21.

[0127] Furthermore, in the case of a configuration having two screens as shown in Figure 21, in order to make it clear to the user that the two screens are the liquid crystal display screen 2101 and the floating image display unit 2102, a display indicating this may be placed on each screen, for example, "This is a liquid crystal display screen" or "This is a floating image display screen." This improves usability for the user. Alternatively, instead of displaying it on the screen, the labels "Liquid crystal display screen" and "Floating image display screen" may be physically placed in the vicinity of the frame of each screen beforehand.

[0128] In the example shown in Figure 21, a user of the kiosk terminal 2100 can use the services of the kiosk terminal 2100 while viewing not only the video displayed on the LCD screen 2101, but also the video displayed on the floating video display unit 2102 using floating video 3. For example, the user can operate operation menus and other functions displayed on the floating video display unit 2102 as floating video 3, following the operation guidance provided by the avatar 2105 using floating video 3. The avatar 2105 provides operation guidance to the user through video and audio.

[0129] Therefore, users can get the feeling that 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. As a result, even users who are using the kiosk terminal 2100 for the first time can operate it more easily without confusion and receive the desired service.

[0130] In addition, the kiosk terminal 2100 may normally keep at least one of its two screens, the LCD display screen 2101 and the floating image display unit 2102, in a sleep state. When a person approaches the front 501a of the housing 501, detected by a human presence sensor 2106 or the like, the display on at least one of the two screens, the LCD display screen 2101 and the floating image display unit 2102, may be activated. For example, when the kiosk terminal 2100 detects that a person is approaching using the human presence sensor 2106, it may first display the avatar 2105 as the floating image 3 on the floating image display unit 2102 and start providing operation guidance, etc.

[0131] The method for forming the floating image 3 in the floating image display unit 2102 is a lower-edge projection method as shown in Figure 5B, using the retroreflective optical system described above. The user operates buttons and other controls on the operation menu displayed on the floating image 3 with their fingers or other body parts. At that time, the surface of the floating image 3 is floating and protruding forward from the retroreflective member 5 on the front surface 501a of the housing 501, making it difficult for fingers or other body parts to come into contact with the retroreflective member 5 on the front surface 501a. In particular, the lower edge of the floating image 3 protrudes further forward than the upper edge. Therefore, when buttons and other controls for the operation menu are located at the bottom of the floating image 3, it is preferable that the user does not physically come into contact with the back of the image when pressing those buttons or controls.

[0132] Furthermore, in the configuration example shown in Figure 21, the aforementioned aerial sensor 50 is positioned on the back of the frame portion between the two screens on the front surface 501a of the housing 501.

[0133] As a variation, 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 the images from the cameras to detect when a person approaches the front 501a of the housing 501. The kiosk terminal 2100 may also use the images from the cameras to identify and authenticate the user.

[0134] Furthermore, the kiosk terminal 2100 may be equipped with a speaker or the like at any location on the housing 501. The kiosk terminal 2100 may use its speaker or the like to output voice messages to the user, such as operation sounds or operation guidance.

[0135] Figure 22 is an explanatory diagram of the internal structure of the kiosk terminal 2100 shown in Figure 21. Figure 22 shows an internal YZ cross-sectional view of the upper part of the housing 501 in Figure 21, 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 a right-angled triangle in shape. Within the space inside the housing 501, the upper space 2210 contains a liquid crystal display device including the liquid crystal display screen 2101. The lower space 2220 contains the floating image display device of Embodiment 1. Specifically, a retroreflective member 5 is positioned in line with the front surface 501a, and the image display device 1 is positioned in space 2220 so as to stand in the vertical Z-axis direction, similar to Figure 17.

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

[0137] The user can operate the operation menu, etc., displayed as a floating spatial image 3 using their fingers UH or the like. The aerial sensor 50 detects the position of the operation. The control device, which is connected to the aerial sensor 50 by communication, detects the user's operation based on the detection signal from the aerial sensor 50 and performs control according to the detected operation. For example, the control device changes the content of the floating spatial image 3, i.e., the content of the video signal to the video display device 1, according to the operation.

[0138] The inclined surface 501a of the housing 501 and the retroreflective member 5 are arranged, for example, at a predetermined angle β with respect to the horizontal plane. This angle β is larger than the similar angle in the system shown in Figure 5A, allowing the inclined surface 501a to be a surface closer to the vertical. Consequently, the depth dimensions of the housing 501, such as the upper dimension 2231 and the lower dimension 2232, can be made smaller than the similar dimensions in the system shown in Figure 5A. Furthermore, the spatial floating image display device of Embodiment 1 can be compactly housed within the housing 501, which thus has limited depth space.

[0139] In addition, as mentioned above, the impact of heat from the light source unit 31A on the flexible cable 703 and other components can be reduced. In the space 2230 inside the housing 501, the heat generated by the light source unit 31A and the power supply board 705 flows from bottom to top in the Z-axis direction corresponding to the vertical direction. The flexible cable 703 and other components located at the bottom of the space 2230 are less affected by the heat. If the housing 501 is provided with a ventilation or cooling mechanism, for example, ventilation holes on the back of the housing 501, the heat from the light source unit 31A and other components will flow to the outside through the ventilation holes.

[0140] As an alternative, the sensing system using the aerial sensor 50 may be used to detect whether a person is approaching the front surface 501a of the kiosk terminal 2100. The light emitted from the position of the aerial sensor 50 shown in the figure is emitted along the plane of the floating image 3 and extends to the area beyond. Therefore, if there is a person's torso or the like in the area beyond, it can be detected as reflected light.

[0141] <Second example of kiosk terminal configuration> Figure 23 shows a perspective view from the upper right as an example of the external configuration of a kiosk terminal 2300 equipped with the spatial floating image display device of Embodiment 1. Figure 23 shows a second configuration example of the kiosk terminal. The differences between the kiosk terminal 2300 in Figure 23 and the kiosk terminal 2100 in Figure 21 are as follows.

[0142] The housing 501 in Figure 23 does not have a liquid crystal display screen 2101 on its front surface 501a, but instead has a floating image display unit 2301 covering almost the entire surface. This floating image display unit 2301 is composed of the floating image display device of Embodiment 1. In other words, the kiosk terminal 2300 has one screen consisting of a floating image 3 displayed on the floating image display unit 2301.

[0143] In the configuration example shown in Figure 23, the floating-space video display unit 2301 displays a video created using the floating-space video 3 as a user interface. The video may include, for example, an avatar or an operation menu. Figure 23 shows an example where the floating-space video 3 displays an avatar 2305 that guides users through services, and an operation menu 2306 side-by-side, one above the other. The floating-space video display unit 2301 may also display either the avatar 2305 or the operation menu 2306, switching between them as needed.

[0144] The screen of the floating image display unit 2301 is based on an area of ​​predetermined size in both length and width. In this example, the screen has a vertical orientation. A floating image display device equipped with a light source assembly 30 as shown in Figure 17 can secure this screen size. The screen size of the floating image display unit 2301 is, for example, 10 to 20 inches.

[0145] In the example shown in Figure 23, a user of the kiosk terminal 2300 can use the services of the kiosk terminal 2300 while viewing the floating video 3 displayed on the relatively large floating video display unit 2301. For example, the user can operate the operation menu 2306 and other functions displayed as the floating video 3 by following the operation guidance provided by the avatar 2305 of the floating video 3.

[0146] Furthermore, in the configuration example shown in Figure 23, the aforementioned aerial sensor 50 is positioned on the back of the upper frame portion of the screen of the floating video display unit 2301 on the front surface 501a of the housing 501.

[0147] Figure 24 shows an explanatory diagram of the internal structure of the kiosk terminal 2300 shown in Figure 23. Figure 24 shows an internal YZ cross-sectional view of the upper part of the housing 501 in Figure 23, viewed from the X-axis direction corresponding to the right side. The upper part of the housing 501 has a sloping front surface 501a in the YZ cross-section and is roughly trapezoidal in shape. In the configuration example in Figure 24, the height dimension of the housing 501 can be shortened by not providing the liquid crystal display screen 2101 shown in Figure 22. Alternatively, if the height dimension of the housing 501 is to be the same as in Figure 22, the screen size of the floating image display unit 2301 may be increased by using a larger floating image display device overall.

[0148] Within the space 2430 inside the housing 501, the floating video display device of Embodiment 1 is arranged. Specifically, the retroreflective member 5 is positioned to cover almost the entire surface of the front surface 501a, and the video display device 1 is positioned within the space 2430 so as to stand in the vertical direction, the Z-axis direction, as shown in Figure 17.

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

[0150] The inclined surface 501a of the housing 501 and the retroreflective member 5 are arranged, for example, at a predetermined angle β with respect to the horizontal plane. This angle β is larger than a similar angle in the system shown in Figure 5A, allowing the inclined surface 501a to be a surface closer to the vertical. Consequently, the depth dimensions of the housing 501, such as the upper dimension 2431 and the lower dimension 2432, can be made smaller than the similar dimensions in the system shown in Figure 5A. Furthermore, the spatial floating image display device of Embodiment 1 can be compactly housed within the housing 501, which thus has limited depth space.

[0151] In addition, as mentioned above, the impact of heat from the light source unit 31A on the flexible cable 703 and other components can be reduced. In the space 2430 inside the housing 501, the heat generated by the light source unit 31A and the power supply board 705 flows from bottom to top in the Z-axis direction corresponding to the vertical direction. The flexible cable 703 and other components located at the bottom of the space 2430 are less affected by the heat. If the housing 501 is provided with a ventilation or cooling mechanism, for example, ventilation holes on the back of the housing 501, the heat from the light source unit 31A and other components will flow to the outside through the ventilation holes.

[0152] As described above, the floating video display device of Embodiment 1 can be compactly housed and mounted in the housing of a floating video display system such as a kiosk terminal, and is easy to mount even when the depth dimension of the housing of the floating video display system is limited. As shown in Figures 5B, 22 and 24, the floating video 3 is a bottom-side projection type, and the video display device 1 can be arranged vertically within the system housing 501, and the retroreflective member 5 can be arranged to match the sloping front surface 501a, so the floating video display device of Embodiment 1 is easy to mount in a system.

[0153] Furthermore, as mentioned above, since the flexible cable 703 and the like are routed in the lower space within the housing 501 of the kiosk terminal or other spatial floating image display system, deterioration of the heat-sensitive flexible cable 703 and the like can be prevented. In addition, in conventional systems such as kiosk terminals, if there is a housing 501 with limited depth dimensions as shown in Figure 5B, the spatial floating image display device of Embodiment 1 can be easily housed by reusing that housing 501.

[0154] <Example of a light source device configuration> Using Figures 25A to 25G, an example configuration of a light source assembly 30 applicable as the light source device 13 of the spatial floating image display device of Embodiment 1 described above will be explained. This example configuration shows the optical system configuration for a light source device that improves light utilization efficiency by 1.8 times using polarization conversion.

[0155] Figures 25A, 25B, 25C, 25D, and 25E show examples of the configuration of a light source assembly 30, which is a light source device 13. Figures 25A and 25E show an embodiment without a sub-reflector, while Figures 25B and 25C show a modified example with sub-reflectors 310 and 308. Figure 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 Figure 17 and other figures mentioned above. Figure 25E corresponds to a longitudinal cross-sectional view of a part of Figure 25A. Figure 25B is an enlarged perspective view of a part of the unit 312 corresponding to the light source in the modified example. Figure 25C is a longitudinal cross-sectional view of the part of the unit 312 in Figure 25B that includes the subsequent polarization conversion element 21, etc. Figure 25D is an enlarged view of a part of the reflective surface 307 of the light guide 306 in the embodiment.

[0156] In Figures 25A and 25E, the light ray assembly 30 includes a unit 312 containing an LED 12, which is a light source, and a reflector 300, a polarization conversion element 21, and a light guide 306, which is a reflective light guide, in the Z-axis direction. The polarization conversion element 21 is positioned at a predetermined distance from the unit 312 in the Z-axis direction, and the light guide 306 is positioned behind the polarization conversion element 21. A diffuser plate 206 is positioned in the Y-axis direction relative to the light guide 306. The liquid crystal panel 11 is positioned on the upper surface side of the diffuser plate 206.

[0157] Figures 25A to 25E show the LEDs 14 that constitute the light source mounted on the substrate 102. These are configured as a unit 312 having multiple blocks, with the reflector 300 and the LED 14 forming a pair of blocks. The multiple blocks are arranged in the X-axis direction. The multiple reflectors 300 may be formed as a single unit, as shown in the figure.

[0158] In Figures 25A, 25F, and 25G, the heatsink 330 is not shown. In the embodiment shown in Figure 25E, an example configuration of the heatsink 330 is illustrated. In the modified example shown in Figure 25C, another example configuration of the heatsink 330 is illustrated. In Figure 25E, the heatsink 330 has a portion that contacts the substrate 102 on the back side along the Y-axis and a portion that contacts the reflector 300 on the lower Z-axis side. In Figure 25B, the heatsink 330 is provided in contact with the back side of the substrate 102 along the Y-axis. Generally, metallic substrates 102 generate heat. In particular, the substrate 102 generates heat from the LED 14, which is a light source provided on the surface side. Therefore, a heatsink 330 is provided to cool the heat of the substrate 102.

[0159] A reflector 300 is positioned above the LED 14 on the surface of the substrate 102, along the Y-axis. The reflector 300 converts the divergent light emitted from the LED 14, with the Y-axis as the optical axis, into a nearly parallel luminous beam by reflecting it in the direction of the Z-axis. This nearly parallel luminous beam is shown as luminous beam φ5 in Figures 25E and 25C.

[0160] The reflective surface of the reflector 300 may have an asymmetric shape with respect to the optical axis of the light emitted from the LED 14. The reason for this will be explained using Figure 25B. In this embodiment, the reflective surface of the reflector 300 is a parabolic surface, and the center of the light-emitting surface of the LED 14, which is a surface light source, is positioned at the focal point of the parabolic surface. Furthermore, due to the characteristics of the parabolic surface, the light emitted from the four corners of the light-emitting surface of the LED 14 is also approximately parallel, with only the direction of emission differing. Therefore, even if the light-emitting part has an area, if the distance between the polarization conversion element 21, which is located downstream, and the reflector 300 is short, the amount of light incident on the polarization conversion element 21 and the conversion efficiency will be hardly affected.

[0161] Furthermore, even if the mounting position of the LED 14 is shifted in the XZ plane relative to the focal point of the corresponding reflector 300, an optical system that can mitigate the decrease in light conversion efficiency can be realized for the reasons mentioned above. Moreover, even if the mounting position of the LED 14 is scattered in the Y-axis direction, only the converted parallel light beam moves in the YZ plane, significantly reducing the mounting precision required for the LED 14, which is a surface light source.

[0162] In this embodiment, a reflector 300 having a reflective surface formed by cutting out a portion of a parabolic surface along the meridian (north-south line) is described, but LEDs 14 may be placed in a portion of the cut-out portion of the entire parabolic surface to serve as a reflective surface.

[0163] On the other hand, in this embodiment, as shown in Figures 25E and 25C, the divergent light from the LED 14 is reflected by the parabolic surface 321 to convert it into approximately parallel light, which is then incident on the end face of the subsequent polarization conversion element 21, where the polarization conversion element 21 adjusts it to a specific polarization. The polarization conversion element 21 is composed of, for example, a combination of a polarization conversion prism and a waveplate 213. This distinctive configuration increases the light utilization efficiency by 1.8 times compared to the conventional example, enabling the realization of a highly efficient light source.

[0164] However, at this time, the approximately parallel light reflected by the parabolic surface 321 from the divergent light emitted from the LED 14 is not all uniform. Therefore, in this embodiment, the light beam φ6, which is the approximately parallel light that has passed through the polarization conversion element 21, is made incident toward the liquid crystal panel 11 perpendicular to the liquid crystal panel 11 by adjusting the angular distribution of the reflected light using the multiple inclined reflective surfaces 307 in the light guide 306.

[0165] In this example, the direction of the principal ray in the light entering the reflector 300 from the LED 14 and the direction of the light entering the liquid crystal panel 11 are arranged to be approximately parallel. In examples such as Figure 25A, they are arranged to be approximately parallel along the Y-axis. This arrangement is easy to implement in terms of design, and it is preferable to place the heat source below the light source device 13 because air can escape from bottom to top, thereby reducing the temperature rise of the LED 14.

[0166] Furthermore, as shown in the modified example in Figure 25C, in order to improve the capture rate of divergent light from the LED 14, the following configuration is provided for capturing the light beam that cannot be captured by the reflector 300. In this modified example, 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 in the direction 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, which is positioned diagonally above the exit side of the reflector 300. Furthermore, the reflected light beam is reflected by the inclined surface of the sub-reflector 310 provided below the reflector 300 on the substrate 102. The reflected light beam is incident on the effective region of the subsequent polarization conversion element 21 in the Z-axis direction. This further improves the efficiency of light utilization.

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

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

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

[0170] The light guide 306 has an overall shape in which the inclination increases in the X-axis direction from the side closer to the unit 312 to the side further away from it. The reflective surface 307 has a large Y-axis aperture distance between it and the diffuser plate 206 on the side closer to the unit 312, and a small distance on the side further away from the unit 312. In addition, a side wall 400 is provided on the outer side of the light guide 306 in the X-axis direction to prevent light incident on the reflective surface 307 and reflected from escaping to the outside.

[0171] The reflective surface 307 provided on the light guide 306 is configured to have multiple inclinations on a single surface, as shown in Figure 25D. This enables more precise adjustment of reflected light. Figure 25D shows how, for example, light rays R7 to R10 in the light beam φ6 from the polarization conversion element 21 are reflected at the respective inclination points P7 to P10 on the reflective surface 307. In addition, the configuration of the reflective surface 307 to have multiple inclinations on a single surface means that the area used as the reflective surface 307 may be multiple surfaces, multifaceted, or curved. Furthermore, the diffuser effect of the diffuser plate 206 in Figure 25A enables a more uniform light intensity distribution for the reflected light from the reflective surface 307. Light incident on the diffuser plate 206 on the side closer to the LED 14 in the Z-axis direction achieves a uniform light intensity distribution by changing the inclination of the reflective surface 307.

[0172] In this embodiment, the base material of the reflective surface 307 is a plastic material such as heat-resistant polycarbonate. Furthermore, the angle of the reflective surface 307 corresponding to the moment immediately after the emission of light 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 reflective surface 307.

[0173] In this embodiment, the LED 14 and the reflector 300 are arranged in close proximity in some areas, but heat can be dissipated into the space on the opening side of the reflector 300, thereby reducing the temperature rise of the LED 14 and also reducing the impact on the aforementioned relay board 702 and flexible cables 701 and 703. Another modification is to arrange the board 102 and the reflector 300 in the Y-axis direction in the inverted orientation from the arrangement shown in Figures 25A to 25E.

[0174] However, if the substrate 102 is placed on the upper side of the reflector 300, the substrate 102 will be closer to the liquid crystal panel 11, which may make the layout difficult. Therefore, as shown in the figure, placing the substrate 102 on the lower side of the reflector 300, on the side further from the liquid crystal panel 11, results in a simpler configuration within the device.

[0175] In Figures 25E and 25C, a light-shielding plate 410 is provided on the light incident surface of the polarization conversion element 21 to prevent unwanted light from entering the subsequent optical system. The light-shielding plate 410 shown is positioned in the upper and lower regions of the incident surface, excluding the effective region, in the Y-axis direction. This configuration enables the realization of a light source device 13 with suppressed temperature rise.

[0176] The polarizing plate provided on the light incident surface of the liquid crystal panel 11 reduces the temperature rise by absorbing the light beam with aligned polarization in this embodiment. When the polarization direction of the light beam with aligned polarization in this embodiment is reflected by the light guide 306, some of the light is absorbed by the polarizing plate 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 and the temperature rise caused by the light incident on the electrode pattern. However, since sufficient space is secured between the reflective surface 307 of the light guide 306 and the liquid crystal panel 11, natural cooling is possible.

[0177] In the configuration shown in Figure 25E, the sub-reflectors 308 and 310 shown in Figure 25C are not provided, and the diffuser plate 206 and the upper end of the reflector 300 are connected by a light-shielding plate 401. At the incident surface between the light guide 306 and the diffuser plate 206, the polarization conversion element 21 and the light-shielding plate 410 are positioned at the bottom, and the top is open. The light-shielding plate 401 in Figure 25E and the light-shielding plates 309 and 402 in Figure 25C can also reduce the impact on the relay substrate 702 and flexible cables 701 and 703.

[0178] Figures 25F and 25G show modified versions of the light source device 13 shown in Figures 25E and 25C. Figures 25F and 25G illustrate modified versions of a portion of the light source device 13. The other components are the same as those of the light source device 13 shown in Figures 25E and 25C, so their illustration and repeated explanations are omitted. Figures 25F and 25G show the YZ cross-section.

[0179] First, in the modified example shown in Figure 25F, the sub-reflector 310 on the substrate 102 in Figure 25C has a recess 319 and a protrusion 318. Figure 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 principal fluorescent ray f1, which is output laterally in the Z-axis direction from the phosphor 114 positioned above the LED 14, passes through the recess 319. In Figure 25F, the principal fluorescent ray f1 is shown 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 principal fluorescent ray f1, which is output laterally from the phosphor 114, is incident on the effective region of the polarization conversion element 21 without being obstructed by the light-shielding plate 410.

[0180] Furthermore, the reflective surface of the protrusion 318 of the uneven surface at the top of the sub-reflector 310 reflects the light reflected by the sub-reflector 308 in order to guide the light reflected by the sub-reflector 308 to the light guide 306 (Figure 25C). The light reflected by the protrusion 318 is reflected by the reflective surface 321 of the reflector 300 and directed toward the polarization conversion element 21 in the Z-axis direction. Therefore, the height of the protrusion 318 is adjusted so that the light reflected by the sub-reflector 308 is reflected and incident upon the effective region of the subsequent polarization conversion element 21. This further improves the efficiency of light utilization.

[0181] As shown in Figure 25B, the sub-reflector 310 is arranged to extend in one direction corresponding to the X-axis and has an uneven surface. Furthermore, the top of the sub-reflector 310 has one or more recesses arranged periodically along one direction. By having such an uneven surface, the principal fluorescence ray f1 emitted laterally from the phosphor 114 can be configured to be incident on the effective region of the polarization conversion element 21.

[0182] Furthermore, the uneven shape of the sub-reflector 310 is arranged periodically at a pitch such that the recesses 319 are located at the positions of the LEDs 14 in the X-axis direction. In other words, each of the phosphors 114 is periodically arranged along one direction corresponding to the pitch of the recesses 319 in the uneven shape of the sub-reflector 310. Note that if the LED 14 is equipped with phosphors 114, the phosphors 114 may be described as the light-emitting part of the light source.

[0183] Furthermore, as shown in the modified example in Figure 25G, the sub-reflector 310 may be omitted. In the modified example in Figure 25G, similar to Figure 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 principal fluorescence ray f1 emitted from the phosphor 114 in the Z-axis direction (horizontally) is incident on the effective region of the polarization conversion element 21 without being obstructed by the light-shielding plate 410.

[0184] Furthermore, regarding the light source device 13 shown in Figures 25A to 25G above, as shown in Figure 25A, a side wall 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. In Figure 25A, the side wall 400 is schematically shown as transparent. When a side wall 400 is provided, the side wall 400 is positioned on both the front and rear sides in the X-axis direction so as not to create an opening by sandwiching the space between the polarization conversion element 21, the light guide 306, the diffuser plate 206, and the liquid crystal panel 11 in the X-axis direction. The side wall 400 may also be part of the cover of the floating image display device.

[0185] As shown in Figures 25E and 25C, the light-emitting surface of the polarization conversion element 21, which emits a light beam φ6 that has been polarized, faces the space 1801 enclosed by the light guide 306, the diffuser plate 206, the polarization conversion element 21, and the side wall 400. Furthermore, of the inner surfaces of the side wall 400 in the X-axis direction, the surface that covers the space to the right of the emission surface of the polarization conversion element 21 from the side in the X-axis direction, as the space from which light is output from the emission 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 side wall 400 facing the above space 1800 has a reflective region having a reflective film. By making this part of the inner surface of the side wall 400 a reflective surface, the light reflected by this reflective surface can be reused as light source light. This makes it possible to improve the brightness of the light source device 13.

[0186] Of the inner surfaces of the side wall 400, the surface that covers the polarization conversion element 21 from the side is a surface with low light reflectivity, in other words, a black surface without a reflective film. This is because if reflected light is generated on the side of the polarization conversion element 21, light with an unexpected polarization state will be generated, causing stray light. In other words, by making the above surface a surface with low light reflectivity, the generation of stray light and light with an unexpected polarization state in the image can be prevented or suppressed. Furthermore, a hole for air to pass through may be provided in a part of the side wall 400 to improve the cooling effect.

[0187] The light source devices 13 shown in Figures 25A to 25G were described assuming a configuration using a polarization conversion element 21. That is, in these configurations, the randomly polarized light from the LED 14 can be aligned to light with a specific polarization. However, as a modification, these light source devices 13 may be configured without the polarization conversion element 21. In this case, the light source device 13 can be provided at a lower cost.

[0188] Based on the above-described example of the light source device 13 configuration, the light source assembly 30 shown in Embodiment 1 and other embodiments can be constructed. For example, the light source device 13 in Figure 25A is configured assuming a predetermined size for the display screen size of the liquid crystal panel 11 to be applied, and the light guide 306 is designed with dimensions and shape to match the display screen size of the liquid crystal panel 11 in the Z-axis direction. The dimensions of this light guide 306 can be adjusted to some extent. On the other hand, as in the above-described embodiment, if the display screen size of the liquid crystal panel 11 required by the system to be applied is relatively large, it is possible to accommodate the required display screen size by combining multiple light source devices 13 such as Figure 25A in parallel. That is, as in Embodiment 1 above, a light source assembly 30 can be constructed by symmetrically arranging two light source devices 13 such as Figure 25A as a pair in one direction, and arranging one liquid crystal panel 11 etc. in the other direction relative to one pair of light guides 306.

[0189] [Note] The above describes in detail various specific examples as embodiments of this disclosure. However, the invention is not limited to the embodiments described above, and various modifications are included. For example, although the embodiments described above describe the entire system in detail for clarity, the invention is not limited to having all the configurations described. It is possible to replace parts of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add configurations from other embodiments to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace parts of the configuration of each embodiment with other configurations. Combinations of each embodiment are also possible. Unless otherwise specified, each component can be singular or plural.

[0190] The light source device described above is not limited to spatial floating image display devices, but can also be applied to various display devices and systems such as head-up displays, tablet terminals, and digital signage.

[0191] In the technology according to this embodiment, by displaying high-resolution and high-brightness floating images in a floating state, users can, for example, operate the device without feeling anxious about contact transmission of infectious diseases. If the technology according to this embodiment is used in a system used by an unspecified number of users, it becomes possible to reduce the risk of contact transmission of infectious diseases and provide a contactless user interface that can be used without anxiety. The present invention, which provides such technology, contributes to the United Nations' Sustainable Development Goal (SDG) 3, "Good Health and Well-being."

[0192] Furthermore, in the technology according to the embodiment described above, by reducing the divergence angle of the emitted image light and aligning it to a specific polarization, only the normally reflected light is efficiently reflected by the retroreflective member, resulting in high light utilization efficiency and the ability to obtain bright and clear floating images in space. According to the technology according to this embodiment, it is possible to provide a highly usable non-contact user interface that can significantly reduce power consumption. The present invention, which provides such technology, contributes to the United Nations' Sustainable Development Goals (SDGs) "9. Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation" and "11. Make cities and human settlements inclusive, safe, and resilient and sustainable."

[0193] Furthermore, the technology according to the above embodiment makes it possible to form floating images in space using highly directional (in other words, straight-line) video light. With the technology according to this embodiment, even when displaying images that require high security, such as in bank ATMs or train station ticket machines, or highly confidential images that should be kept hidden from people facing the user, it is possible to provide a contactless user interface that reduces the risk of anyone other than the user looking at the floating images in space by displaying highly directional video light. By providing the above-described technology, the present invention contributes to "SDG 11: Make cities and human settlements inclusive, safe, resilient and sustainable," one of the Sustainable Development Goals (SDGs) advocated by the United Nations. [Explanation of Symbols]

[0194] 1...Image display device, 3...Floating image in space, 5...Retroreflective member, 11...Liquid crystal panel, 13...Light source device, 30, 30A, 30B...Light source assembly, 31A, 31B...Light source unit, 32A, 32B...Light guide unit, 50...Air sensor, 204...Diffuser plate, 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 display device, Light source device, A video display element that emits video light based on light from the aforementioned light source device, The light source device is equipped with a power supply board that supplies power to the aforementioned light source device, The flexible cable or circuit board connected to the image display element is arranged to bypass the light source unit of the light source device and wrap around to the back side of the light source device, so as to create a space between it and the light source unit of the light source device. The power supply board is positioned on the rear side of the light source device, perpendicular to and above the flexible cable and the board. Display device.

2. In the display device according to claim 1, The flexible cable or circuit board connected to the video display element includes a first flexible cable that extends from the bottom edge of the display screen of the video display element, A relay board connected to the first flexible cable, A second flexible cable connected to the relay board, The system includes a video signal processing board connected to the second flexible cable, The second flexible cable is arranged to bypass the light source unit and wrap around to the back side of the light source unit, so as to create a space between it and the light source unit of the light source unit. Display device.

3. In the display device according to claim 1, The system includes the aforementioned video display element, the flexible cable, and a cover that houses and secures the substrate. Display device.

4. In the display device according to claim 1, The aforementioned light source device is The light source unit comprises a light source and a reflector that reflects light from the light source. It has a light guide that guides light from the reflector toward the image display element, Display device.

5. In the display device according to claim 1, The light source device comprises a first light source assembly and a second light source assembly arranged symmetrically with respect to a center line. The first light source assembly comprises a first light source section and a first light guide section. The second light source assembly comprises a second light source section and a second light guide section. The flexible cable is arranged to bypass the first light source unit and wrap around to the back side of the light source device, so as to create a space between it and the first light source unit. Display device.

6. In the display device according to claim 4, The light guide is a reflective light guide having multiple inclined reflective surfaces. Display device.

7. The display device according to claim 1 is To display images in the air in a visible way. Display device.

8. A head-up display device comprising the display device described in claim 1.

9. Digital signage equipped with the display device described in claim 1.

Images