Portable spatial suspension image display system

Abstract

The purpose of the present invention is to appropriately display an image to the outside of a space. According to the invention, it is possible to contribute to the sustainable development goals' 3 good health and welfare ',' 9 industry, innovation and infrastructure ', and' 11 sustainable cities and communities'. The spatial floating image display system includes a housing for holding a display panel and a light source device, and a power source, and includes a power source unit connected to the housing via a first connection portion, and a frame structure connected to the housing via a second connection portion and holding a retro-reflective member.

Description

Technical Field

[0001] The invention relates to a portable space suspended image display system and an optical system used therein. Background Art

[0002] Regarding the spatial floating image display system, an image display device that directly displays an image to the outside and a display method that displays an image as a spatial screen (spatial screen) are already known. In addition, regarding a retro-reflective component for displaying a spatial image, for example, Patent Document 1 has disclosed it. In addition, for example, Patent Document 2 has also disclosed it.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2017-067933

[0006] Patent Document 2: Japanese Patent Application Publication No. 2019-133109 Summary of the invention

[0007] Technical problem to be solved by the invention

[0008] Regarding the spatial floating image display system, an image display device that directly displays an image to the outside and a display method that displays the image as a spatial screen are already known. However, in the above-mentioned prior art spatial floating image device, although the structure and configuration of the retro-reflective component for generating the spatial floating image and the method of irradiating the image light from the image light source are recorded, the structure and design method of the implementation technology of the portable spatial floating image display system are not considered.

[0009] The object of the present invention is to provide a technology for realizing a portable spatial floating image display system or a spatial floating image display device.

[0010] Technical solutions to the problem

[0011] In order to solve the above problem, for example, the structure described in the technical solution claimed for protection is adopted. The present application includes a variety of solutions to the above problem, and a spatial floating image display device is cited as one example. The spatial floating image display system as an example of the present application includes a housing for holding a display panel and a light source device, and a power supply, and includes a power supply unit connected to the housing via a first connection portion, and a frame structure body movably connected to the housing via a second connection portion and holding a retro-reflective component.

[0012] Effects of the Invention

[0013] According to the present invention, a portable system can be realized for a spatial floating image display system or a spatial floating image display device. Other problems, features and effects than those described above will become clear through the description of the following embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1A It is a diagram showing the structure of a transmission-type retroreflective member and the position at which a spatially suspended image is generated according to one embodiment of the present invention.

[0015] Figure 1B It is an explanatory diagram for explaining the characteristics of an optical member constituting a transmission type retroreflective member according to an embodiment of the present invention.

[0016] Figure 2 It is a diagram showing the structure of a reflection type retroreflective member and the generation position of a spatial floating image according to one embodiment of the present invention.

[0017] Figure 3 This is a structural diagram showing an example of a specific structure of a liquid crystal panel according to an embodiment of the present invention.

[0018] Figure 4 It is a structural diagram showing the arrangement of a light source device and a liquid crystal panel according to one embodiment of the present invention.

[0019] Figure 5 It is a side view showing the structure of a spatial floating image display system according to an embodiment of the present invention.

[0020] Figure 6 1 is a top view showing the structure of a spatial floating image display system according to an embodiment of the present invention.

[0021] Figure 7 It is a second side view showing the structure of the spatial floating image display system according to one embodiment of the present invention.

[0022] Figure 8 3 is a third side view showing the structure of the spatial floating image display system according to one embodiment of the present invention.

[0023] Fig. 9 4 is a side view showing the structure of the spatial floating image display system according to one embodiment of the present invention.

[0024] Fig.10 It is a first front view showing the structure of a spatial floating image display system according to an embodiment of the present invention.

[0025] Fig.11 3 is a fifth side view showing the structure of the spatial floating image display system according to one embodiment of the present invention.

[0026] Fig.12It is a second front view showing the structure of the spatial floating image display system according to one embodiment of the present invention.

[0027] Fig.13A It is a diagram showing the structure of a spatial floating image display system according to an embodiment of the present invention.

[0028] Fig. 13B It is a three-dimensional diagram showing the structure of a spatial floating image display system according to an embodiment of the present invention.

[0029] Fig. 13C It is a front view showing the structure of a spatial floating image display system according to an embodiment of the present invention.

[0030] Fig.13D It is a top view showing the structure of a spatial floating image display system according to an embodiment of the present invention, and is a structural diagram of a part of a shell viewed through perspective.

[0031] Fig.13E It is a side view showing the structure of a spatial floating image display system according to an embodiment of the present invention.

[0032] Fig.13F It is a diagram showing the structure of a spatial floating image display system according to an embodiment of the present invention.

[0033] Fig.14 The diagrams are perspective, plan, and cross-sectional views showing examples of specific structures of the light source device.

[0034] Fig.15A It is a structural diagram showing another example of the specific structure of a light source device of another form.

[0035] Fig. 15B This is a diagram showing a part of another example of a specific structure of a light source device in another form.

[0036] Fig. 15C This is a diagram showing a part of another example of a specific structure of a light source device in another form.

[0037] Fig.15D This is a diagram showing a part of another example of a specific structure of a light source device in another form.

[0038] Fig.16A It is a structural diagram showing another example of the specific structure of a light source device of another form.

[0039] Fig. 16B It is a diagram showing another example of a specific structure of a light source device of another form.

[0040] Fig.17 This is a cross-sectional view showing an example of a specific structure of a diffusion plate provided in the light source device.

[0041] Fig.18 This is an explanatory diagram for explaining the diffusion characteristics of the image display device.

[0042] Fig.19 This is an explanatory diagram for explaining the diffusion characteristics of the image display device.

[0043] Fig. 20 This is a diagram showing a coordinate system for measuring visual characteristics of a liquid crystal panel.

[0044] Fig.21 This is a diagram showing the luminance angle characteristics (long side direction) of a general liquid crystal panel.

[0045] Fig. 22 This is a diagram showing the luminance angle characteristics (short side direction) of a general liquid crystal panel.

[0046] Fig.23 This is a diagram showing the angular characteristics (long side direction) of the contrast of a general liquid crystal panel.

[0047] Fig.24 This is a diagram showing the angular characteristics (in the short-side direction) of the contrast of a general liquid crystal panel. DETAILED DESCRIPTION

[0048] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. In addition, the present invention is not limited to the contents of the embodiments described below (hereinafter also referred to as "the present disclosure"). The present invention also covers the scope of the technical ideas recorded in the spirit of the invention or the technical scheme for protection or its equivalent scope. In addition, the structures of the embodiments (examples) described below are only examples, and various changes and modifications can be made by technical personnel in the field within the scope of the technical ideas disclosed in this specification.

[0049] In addition, in the drawings used to illustrate the present invention, the same mark is marked on parts with the same or similar functions, different names are used as appropriate, and repeated descriptions of functions, etc. are sometimes omitted. In addition, in the description of the following embodiments, the term "spatial floating image" is used to express an image suspended in space. This term can also be replaced by "aerial image", "spatial image", "aerial floating image", "spatial floating optical image of displayed image", "aerial floating optical image of displayed image", etc. The term "spatial floating image" mainly used in the description of the embodiments is used as a representative example of these terms.

[0050] The present disclosure relates to a portable information terminal and the like, which can display an image formed by image light emitted by a small image light source as a space floating image by using a retro-reflective component.

[0051] According to the following embodiments, for example, a high-resolution image can be displayed in a spatially suspended state on a glass surface of a display window or a light-transmitting plate. At this time, by reducing the divergence angle of the emitted image light to an acute angle and then unifying it into a specific polarization, the retro-reflective component can only reflect the normal reflected light efficiently. Therefore, the light utilization efficiency is improved, and a portable, small, and low-power spatially suspended image display device that cannot be achieved by using the existing retro-reflective method can be obtained.

[0052] In addition, the use of a device and an optical system including the light source disclosed in the present invention can significantly reduce power consumption, and if combined with a novel and small image display device (liquid crystal panel), a low-power and portable spatial floating image display system can be provided. In addition, according to the technology disclosed in the present invention, for example, a spatial floating image information display system for a vehicle can be provided, which can realize the display of a so-called one-way spatial floating image that can be viewed from the outside of the vehicle through the windshield including the front window glass, rear window glass and side window glass of the vehicle.

[0053] Next, the function of the transmissive retro-reflective component used in the spatial floating image display device of the embodiment disclosed in the present invention and a specific embodiment of the spatial floating image display device are described. Figure 1A As shown in (2), generally, the transmissive retroreflective component 2 is tilted at an angle of 40 to 50 degrees relative to the image display device 1. At this time, the spatial floating image 3 is emitted from the transmissive retroreflective component 2 at the same angle as the angle at which the image light is incident on the transmissive retroreflective component 2. At this time, the spatial floating image 3 is formed at a symmetrical position at the same distance as the distance L1 from the image display device 1 to the transmissive retroreflective component 2.

[0054] The following is for the use of Figure 1A and Figure 1B The imaging mechanism of the spatial suspended image of the optical system of the transmission type retro-reflective component 2 shown in FIG. Figure 1A and Figure 1B Detailed description. The image display device 1 is arranged on one side of the transmissive retroreflective component 2, and the image light emitted from the image display device 1 is reflected on the plane light reflection part C (the reflection surface of the light reflection component 20) of the second light control component 22, and then reflected on the plane light reflection part C' (the reflection surface of the light reflection component 20) of the first light control component 21, thereby forming a spatially suspended image 3 (real image) at the outer position of the transmissive retroreflective component 2 (the space on the other side). That is, by using the transmissive retroreflective component 2, a spatially suspended image display device can be realized, and the image of the image display device 1 can be displayed as a spatially suspended image in space.

[0055] The above-mentioned transmission type retro-reflective component 2 has two reflection surfaces as described above, so Figure 1B As shown in (1) and (2), in addition to the spatial floating image 3, two ghost images 3a and 3b corresponding to the number of reflection surfaces are generated.

[0056] In addition, when the intensity of external light is high, when it is incident from the upper surface of the transmissive retroreflective component 2, light interference occurs due to the short interval between the reflection surfaces (less than 300 μm), and rainbow-colored reflected light can be observed, which has the adverse effect of making the observer aware of the presence of the retroreflective component. Therefore, in order to prevent the interference light generated by the interval between the reflection surfaces of the retroreflective component 5 due to the incidence of external light from returning to the observer, the area of ​​the interference light generation was obtained through experiments using the incident angle of the external light as a parameter. As a result, it was found that when the interval between the reflection surfaces was 300 μm and the height of the reflection surface was 300 μm, if the transmissive retroreflective component was tilted at an angle θ of more than 35 degrees relative to the vertical plane, the interference light would not return to the observer.

[0057] It can also be known that under the ratio (H / P) of the spacing P of the above-mentioned light reflecting component 20 to the height H of the reflecting surface, a retro-reflected spatial suspended image is formed by about 60% of the reflecting surface, and the remaining 40% is abnormal reflected light that produces ghost images. In the future, in order to improve the resolution of the spatial suspended image, it is necessary to shorten the spacing of the reflecting surfaces. In addition, in order to suppress the generation of ghost images, it is necessary to increase the height of the reflecting surface compared to the current situation. However, due to the manufacturing limitations of the second retro-reflective component 2, the ratio (H / P) of the spacing P of the reflecting surface to the height H is preferably selected in the range of 0.8 to 1.2 relative to the current 1.0.

[0058] Figure 2 The structure of a reflective retro-reflective component according to an embodiment of the present invention and the basic structure of a spatial floating image display device using the reflective retro-reflective component are shown. Figure 2 As shown, an image display device 1 for narrow-angle diffusion of specific polarized image light is provided on an inclined direction of a transparent member or transmissive plate 100 such as glass. The image display device 1 includes a liquid crystal display panel 11 and a light source device 13 for generating specific polarized light with narrow-angle diffusion characteristics.

[0059] The image light of specific polarization from the image display device 1 is reflected by the polarization separation component 101 (in the figure, the polarization separation component 101 is formed into a sheet and attached to the transparent component 100) provided on the transparent component 100 and has a film that selectively reflects the image light of specific polarization, and enters the retro-reflective component 5. A λ / 4 plate 21 is provided on the image light incident surface of the retro-reflective component 5. The image light passes through the λ / 4 plate 21 twice when it is incident on the retro-reflective component 2 and when it is emitted, thereby undergoing polarization conversion from a specific polarization to another polarization. Here, the polarization separation component 101 that selectively reflects the image light of specific polarization has the property of transmitting polarized light of another polarization after polarization conversion, so the image light of specific polarization after polarization conversion can pass through the polarization separation component 101. The image light that passes through the polarization separation component 101 forms a real image of a space suspended image 3 outside the transparent component 100. The above-mentioned polarization separation component 101 is formed, for example, by a reflective polarizer or a metal multilayer film that reflects a specific polarization.

[0060] Figure 2 In the structure, when the user views from the direction of arrow A, the image 3 suspended in the air appears as a bright image, but when other people view from the direction of arrow B, for example, the image 3 suspended in the air cannot be seen as an image at all. This feature is very suitable for use in a system that displays images requiring high security and displays highly confidential images that are to be kept secret from people facing the user.

[0061] In this embodiment, a structure in which an absorption type polarizing plate 12 is provided on the image display surface of the image display device 1 is described. The absorption type polarizing plate 12 allows the image light emitted from the image display device 1 to pass through the absorption type polarizing plate 12, and absorbs the reflected light returning from the polarization separation component 101 by the absorption type polarizing plate 12, thereby suppressing re-reflection. Therefore, according to this embodiment using the absorption type polarizing plate 12, in a spatial floating image device using a reflective retro-reflective component, it is possible to prevent or suppress image quality degradation caused by ghost images of a spatial floating image.

[0062] Based on the above research results, the inventor has conducted research on the retro-reflective optical system, and in the spatial suspended image display system using the transmissive retro-reflective component or the reflective retro-reflective component, the spatial suspended image can be made high-quality, and at the same time, in combination with the small image display device 1, a portable spatial suspended image display device with low power consumption and battery-driven can be realized, thereby completing the present invention. The present invention is described in detail below using the accompanying drawings.

[0063] <Layout to achieve compactness>

[0064] Figure 32 shows a structure in which a liquid crystal panel 11, a FPC (Flexible printed circuits) 249 and a circuit board 251 are provided. The liquid crystal panel 11 and the circuit board 251 are connected by the FPC 249. Figure 4 As shown, the LED chips as the surface light source are arranged in a row in a direction parallel to the short side of the liquid crystal panel 11. The light from the LED chips is converted into approximately parallel light by the reflector 300, and becomes light of a specific polarization after polarization conversion by the PBS (Polarizing Beam Splitter) 21, and enters the reflective light guide 311, and is reflected on its reflection surface 307 and enters the desired position of the liquid crystal panel 11 at a desired angle. Figure 4 The light source module 312 shown has an inclined gradient, and the FPC 249 of the liquid crystal panel 11 is bent at the lower part of the reflective light guide 311 to configure the circuit board 251. The circuit board 251 is configured along the back side of the reflective light guide 311 to achieve a thinner structure. This structure reduces useless space, so that the light source device 13 and the liquid crystal panel 11 can be compactly stored in the housing.

[0065] use Figure 4 The layout in which the light source module 312 is arranged in the short side direction of the liquid crystal panel 11 is described, but the layout in which the light source module is arranged in the long side direction of the liquid crystal panel 11 is also the same, and in the case where the light source module 312 is arranged oppositely on both sides of the short side or long side of the liquid crystal panel 11, the liquid crystal panel 11, FPC 249 and circuit board 251 can also be arranged in the same manner as described above. By realizing this structure, useless space is reduced, so the light source device 13 and the liquid crystal panel 11 can be compactly stored in the housing.

[0066] <Example 1 of Small Space Suspended Image Display Device>

[0067] Figure 5In the embodiment, the liquid crystal panel 11 and the light source device 13 are built into a compact housing 253, and the housing 253 is connected or linked to a power supply unit 256 by a hinge 255 to form a movable structure. The power supply unit 256 has, for example, a wireless power supply type battery pack. The transmissive retro-reflective component 2 is held by a frame structure 252. With the housing 253 as a reference, the frame structure 252 is movably connected to one side of the housing 253 via a second connecting portion, and the power supply unit 256 is movably connected to the other side of the housing 253 via a first connecting portion. That is, with the housing 253 as a reference, the frame structure 252 is movably connected to one side of the housing 253 via a hinge 254, and the power supply unit 256 is movably connected to the other side of the housing 253 via a hinge 255. The end of the housing 253 connected to the frame structure 252 and the end of the housing 253 connected to the power supply unit 256 are opposite. In addition, one end of the power supply unit 256 is connected to the housing 253 via a hinge 255, and the other side of the power supply unit 256 opposite to the end is not connected to the frame structure 252, but can contact one end of the frame structure 252 when it moves toward the frame structure 252 via the hinge 255. As a result, the transmissive retro-reflective component 2 can be fixed at any angle relative to the housing 253 in which the light source device 13 and the liquid crystal display panel 11 are built, and the transmissive retro-reflective component 2 can be moved arbitrarily.

[0068] When the spatial floating image 3 is displayed, the other side of the frame structure 252 opposite to the end connected to the hinge 254 can be rotated toward the light emitting side of the liquid crystal display panel 11 built in the housing 253 with the hinge 254 as the axis. In addition, the other side of the end of the power supply unit 256 opposite to the hinge 255 can be rotated toward the spatial floating image 3 with the hinge 255 as the axis. As a result, the spatial floating image 3 can be displayed facing the viewer's line of sight. Figure 5 The imaging position of the space suspended image 3 is adjusted to the optimal position and direction by an angle of θ1 relative to the vertical line. In addition, the hinge 255 can also be called a first connecting part, and the hinge 254 can be called a second connecting part. The first and second connecting parts can include a connecting part and a movable part.

[0069] Figure 6 Yes means Figure 5 1 is a top view of the structure of a spatial suspended image display system according to an embodiment of the present invention. Since the upper end of the spatial suspended image 3 will not be imaged above the line segment connecting the viewpoint of the observer and the upper end of the transmissive retro-reflective component 2, in order to increase the sense of suspension, a mark may be added so that the viewpoint can be easily moved to the end of the frame structure 252 facing the observer, especially the upper part, that is, the end that is not connected or linked to the housing 253 by the hinge 254. Furthermore, by providing a black display portion on the upper part of the spatial suspended image 3, the sense of suspension can be increased. Figure 5 and Figure 6 In order to dissipate the heat generated by the LED to the outside, the metal heat sink 104 can be exposed outside the shell, or can be set inside the shell.

[0070] Fig.13A The space suspended image display device shown in the figure has a shell that is roughly cylindrical, especially cylindrical. The space suspended image display device with the cylindrical shell is a relatively small (compact) and movable (portable) space suspended image display device of the bottle holder (also called a drink holder) type that can be stored. For example, such a space suspended image display device can be appropriately configured on a bottle holder (also called a drink holder) or a dashboard in a vehicle. The cylindrical shape is a shape in which the cylinder axis extends in the height direction (corresponding to the vertical direction) and the diameter of the cylinder extends in a direction orthogonal to it (corresponding to the horizontal direction). The cylindrical shell roughly has an upper shell and a lower shell, which are connected to each other. In addition, the upper shell and the lower shell can be connected as a whole or not. The optical system and the control circuit board are stored inside the shell, and a rechargeable battery is stored as needed.

[0071] Fig.13A The structure of a beverage holder type space floating image display system using a transmissive retroreflective member 2 is shown. Fig.13A (1) is a perspective view of a beverage holder type space floating image display system using a transmissive retroreflective component 2, Fig.13A (2) shows a front view of a beverage holder type space floating image display system using a transmissive retro-reflective component 2, Fig.13A (3) shows a side view of a beverage holder type space floating image display system using a transmissive retro-reflective component 2. The space floating image display device of this embodiment includes a power supply unit 256, a frame structure 252, and a housing 253 with an image display device built in. In order to maintain balance, such a beverage holder type space floating image device arranges the retro-reflective component 2 and the image display device on the upper part of the housing, and arranges the power supply unit 256 on the lower part of the housing. The housing 253 has a light source device 13 and a liquid crystal panel 11 built in. The frame structure 252 holds the transmissive retro-reflective component 5. The image display device includes a light source device and a liquid crystal display panel.

[0072] In addition, if Fig.13AAs shown, the housing 253 is disposed obliquely with respect to the power supply unit 256. One end of the housing 253 is fixed to the support portion 258, and the other end of the housing 253 opposite thereto is movably connected to the frame structure 252 via a hinge 260. In addition, the end of the housing 253 connected to the support portion 258 in the present embodiment is referred to as the lower portion, i.e., the side of the power supply unit 256, and the end of the housing 253 connected to the frame structure 252 is referred to as the upper portion. In the vertical direction or the height direction, a recess is formed in the support portion 258, and the housing 253 is fixed to the recess. As Fig.13A shown in (3) of, the support portion 258 has a U-shaped configuration, but is not limited to this shape, and other shapes may be adopted according to the design. The height of the end of the housing 253 movably connected to the frame structure 252 via the hinge is the same as the upper portion of the support portion 258. That is, the height of the opposite end of the end of the housing 253 fixed to the recess is the same as the upper portion of the support portion 258. In Fig.13A (1) of, the image light from the image display device built in the housing 253 is transmitted through the transmissive retroreflective member 2, and a spatial floating image (not shown) is formed in the air on the opposite side of the support portion 258 with respect to the frame structure 252. Corresponding to the user's line of sight, the opposite end of the end of the frame structure 252 connected to the hinge 260 contacts the support portion 258, and can rotate around the hinge 260 toward the spatial floating image side. In addition, the support portion 258 may be referred to as the first connecting portion or the first connection portion, and the hinge 260 may be referred to as the second connecting portion or the first connection portion.

[0073] On the other hand, as Fig.13A another configuration example of the beverage rack type spatial floating image device other than the above configuration, the image display device built in the housing 253 may also be disposed in the height direction of the support portion 258. In this case, since the end of the frame structure 252 is movably fixed to the upper portion of the support portion 258 via the hinge 260, the movable area of the retroreflective member 2 held on the frame structure 252 is larger, and the display position of the spatial floating image can be adjusted corresponding to the user's line of sight. In addition, in order to prevent external light, by providing side walls on the sides of the housing 253 other than the side connected to the hinge 260 and the side connected to the support portion 258, the recognizability of the spatial floating image can be improved. The side walls may also be disposed on both sides of the space surrounded by the housing 253, the support portion 258, and the frame structure 252. The side walls may be detachable, foldable, or retractable. For example, the side walls may be disposed at both ends of the housing 253 without hinges.

[0074] Through the above structure, a space suspended image display system that realizes a miniaturized, portable design and low power consumption can be provided. The space suspended image display system has a display panel for displaying an image and a light source device for the display panel built into the same housing, and a mobile battery and a holding component for holding a transmissive retro-reflective component are respectively connected by hinges, wherein the transmissive retro-reflective component reflects the image light from the display panel and uses the reflected light to display a space suspended image of a real image in the air. Thus, the system form is changed accordingly according to the usage mode to make it portable, and the power consumption can be greatly reduced by making the directional characteristics of the light source device a narrow-angle characteristic.

[0075] <How to fix the floating image in space>

[0076] Figure 7 The present invention is a spatial floating image display system in which the spatial floating image 3 is displayed according to the viewer's line of sight. Figure 7 A second side view of a structure fixed in a direction inclined θ2 relative to the vertical line. The housing 253 is rotatably connected to the power supply unit 256 by a hinge 255. The upper end of the frame structure 252, i.e., the end that is not connected or linked to the housing 253 by the hinge 254, is brought into contact with the end of the power supply unit 256 that is not connected to the housing 253 by the hinge 255, so that the angle between the housing 253 and the transmissive retro-reflective component 2 held in the frame structure 252 is fixed. In addition, the power supply unit 256 is, for example, a wireless power supply type battery pack. By providing hinges at both ends of the housing 253 in which the liquid crystal panel 11 and the light source device 13 are built, the spatial suspended image display system can be provided accordingly according to the usage mode. In addition, in order to prevent external light, by providing side walls on the side surfaces of the housing 253 connected to the hinge 260 and the side surfaces of the housing 253 other than the side surfaces of the housing 253 connected to the support portion 258, the recognizability of the spatial suspended image can be improved. The side walls can be detachable, foldable, or retractable. For example, the side walls may be disposed at both ends of the housing 253 that do not have hinges. Figure 7 As shown, by making the frame structure 252 holding the transmissive retro-reflective component 2 close to vertical relative to the housing 253, the angle of the spatial suspended image 3 can be adjusted in the direction perpendicular to the bottom surface, and the angle can also be adjusted according to the viewpoint direction of the observer. Figure 8 The position of the space suspended image 3 is adjusted accordingly by tilting the direction of θ3 relative to the vertical line. Figure 8 The settings shown are also consistent with Figure 7 Similarly, external light incident on the rear side (right side in the figure) of the transmissive retroreflective member 2, i.e., the light incident surface of the retroreflective member 2, can be shielded, so the image quality, especially the contrast performance, of the spatial suspended image 3 is greatly improved.

[0077] <Example 2 of Small Space Suspended Image Display Device>

[0078] Fig. 9 This is a side view showing a second embodiment of the spatial floating image display device. Similar to the first embodiment, the liquid crystal panel 11 and the light source device 13 are built into a compact housing 253, and the housing 253 and the power supply unit 256 are connected or linked by a hinge 255 to form a movable structure. The power supply unit 256 has, for example, a wirelessly powered battery pack. The transmissive retroreflective component 2 is held by the frame structure 252, and is connected to the housing 253 by a hinge 254 at the end of the housing 253 on the side that is not connected to the power supply unit 256 by the hinge 255. As a result, the transmissive retroreflective component 2 can be fixed at any angle relative to the housing 253 in which the liquid crystal panel 11 and the light source device 13 are built, and is movable. As a result, it can face the observer's line of sight, that is, Fig. 9 The imaging position of the spatial suspended image 3 is adjusted to the optimal position and direction by adjusting the angle θ1 relative to the vertical line. In addition, the hinge 255 can be called the first connecting part, the hinge 254 can be called the second connecting part, and the hinge can also be called the connecting part. In addition, in order to prevent external light, the recognition of the spatial suspended image can be improved by providing side walls on both sides of the triangular prism space surrounded by the shell 253, the power supply unit 256 and the frame structure 252. The side wall can be detachable, foldable, or retractable.

[0079] <The effect of expanding the amount of space caused by the illusion>

[0080] Fig.10 Yes means Fig. 9 The front view of the structure of the spatial suspended image display system of one embodiment of the present invention is shown. The upper end of the spatial suspended image 3, that is, the side where the shell 253 is not configured, will not be imaged above the line segment connecting the viewpoint of the observer and the upper end of the transmissive retro-reflective component 2, that is, the side where the shell 253 is not configured. Therefore, the inventor has studied specific technical means for making people feel the suspension of the spatial suspended image more. As a result, in order to make it easy to move the viewpoint to the end of the frame structure 252 facing the observer, especially the upper part, that is, the end that is not connected or connected to the shell 253 through the hinge 254, a mark 257-1 is added to the end of the frame structure 252 that is not connected to the shell 253 through the hinge 254. Furthermore, the same mark 257-2 and mark 257-3 are added to the side of the frame structure 252, that is, the side of the mark 257-1 that is not opposite to the retro-reflective component 2, so that the observer's attention is attracted to the mark. It was found that this has the effect of making people feel the suspension of the spatial suspended image 3 more than the actual situation. Fig. 9 and Fig.10Different from the first embodiment, the metal heat sink 104 (not shown) for dissipating the heat generated by the LED to the outside is arranged inside the housing and is not exposed. However, the metal heat sink 104 can also be arranged outside the housing.

[0081] <Non-display state of the spatial floating image display device>

[0082] Fig.11 2 is a side view showing a non-display state of the spatial floating image 3 of the spatial floating image display device. The liquid crystal panel 11 and the light source device 13 are built into a compact housing 253, and the housing 253 and the power supply unit 256 are connected or linked by a hinge 255, and arranged side by side in the horizontal direction. That is, the housing 253 and the power supply unit 256 are movable due to the hinge 255, but Fig.11 The angle between the housing 253 and the power supply unit 256 is configured to be about 180 degrees. On the upper part of the housing 253 and the power supply unit 256, the frame structure 252 holding the transmissive retro-reflective component 2 is connected to the housing 253 using a hinge 254. The hinge 254 is provided at the end of the housing 253 on the side not connected to the power supply unit 256 by the hinge 255, so that the frame structure 252 can be folded by the hinge 254. As a result, the transmissive retro-reflective component 2 is fixedly held to overlap with the housing 253 and the power supply unit 256 in which the liquid crystal panel 11 and the light source device 13 are built, and becomes the thinnest structure, achieving a portable thickness. In addition, when the spatial floating image 3 is in a non-display state, the other side of the end of the frame structure 252 connected to the hinge 254 can be rotated and folded toward the light emitting side of the liquid crystal display panel 11 built in the housing 253, or can be rotated and folded toward the opposite side of the light emitting side of the liquid crystal panel 11. When the other side of the end of the frame structure 252 connected to the hinge 254 is rotated and folded toward the light emitting side of the liquid crystal display panel 11, dust and the like can be prevented from adhering to the liquid crystal panel 11. On the other hand, when the other side of the end of the frame structure 252 connected to the hinge 254 is rotated and folded toward the opposite side of the light emitting side of the liquid crystal panel 11, the length of the device can be shortened in the long side direction, but the thickness is increased. In this way, the folding method can be adjusted accordingly according to the needs of the user. In addition, the power supply unit 256 has, for example, a wireless power supply type battery pack.

[0083] Fig.12 Observed from direction A Fig.11 As shown in the stereoscopic diagram A of the spatial floating image display system of an embodiment of the present invention, if the horizontal width, i.e., the vertical thickness and the vertical thickness of the shell 253 and the power supply unit 256 are unified, they can be formed into one body, thereby realizing a spatial floating image display system with better portability.

[0084] In addition, in the spatial floating image display device of the present embodiment, when the observer views the spatial floating image 3, the image display surface of the liquid crystal display panel 11 is also shielded by the reflective surface of the retroreflective component 2. Therefore, in the spatial floating image display device, the liquid crystal display panel and the retroreflective component are arranged at an angle, so it is not easy to directly see the display image of the liquid crystal display panel.

[0085] Furthermore, regarding the image light from the liquid crystal panel 11, since the reflectivity on the reflective components such as the retro-reflective component can be improved in principle, it is more appropriate to use S polarization. However, when the observer uses polarized sunglasses, the air suspension image will be reflected or absorbed on the polarized sunglasses, so as a countermeasure, a depolarizing element 103 can be set on the observer side of the transmission type retro-reflective component 2, that is, on the surface of the space suspension image 3 side, so that a part of the image light of the specific polarization is optically converted into another polarization so as to simulate the conversion into natural light. As a result, even if the observer uses polarized sunglasses, a good space suspension image can be observed. If an adhesive is used to optically join on the transparency plate 100, a reflection surface of light will not be generated, and the image quality of the space suspension image will not be damaged.

[0086] As commercially available products of depolarizing elements, COSMOSHINE SRF (manufactured by Toyobo Co., Ltd.) and depolarizing adhesive (manufactured by Nagase Sangyo Co., Ltd.) can be cited. When COSMOSHINE SRF (manufactured by Toyobo Co., Ltd.) is used, by bonding the adhesive to the image display device, the reflection of the interface can be reduced to improve the brightness. In addition, when the depolarizing adhesive is used, a colorless transparent plate is bonded to the image display device via the depolarizing adhesive and used. In the present embodiment, as described above, the image display device 1 includes a liquid crystal display panel 11 and a light source device 13 that generates light of a specific polarization having a narrow-angle diffusion characteristic.

[0087] <Example 3 of Small Space Suspended Image Display Device>

[0088] Fig. 13B , Fig. 13C , Fig.13D , Fig.13E The structure of a spatial floating image display system using a reflective retro-reflective component 5 is shown. Fig. 13B It is a three-dimensional diagram of a spatial floating image display system using a reflective retro-reflective component 5 . Fig. 13C is a front view of a spatial floating image display system using a reflective retro-reflective component 5, Fig.13D is a top view of a spatial floating image display system using a reflective retro-reflective component 5, Fig.13E It is a side view of a spatial floating image display system using a reflective retro-reflective component 5 . Fig.13DThis is a view showing the interior of the housing 253, and illustrates a portion of the light source device 13. The light source device 13 includes an LED 14, a reflector 300, and a light guide 306. The detailed description of the light source device 13 will be given later, and therefore will be omitted here.

[0089] Figure 13B to Figure 13E is with Figure 2 An embodiment of the present invention shown in the figure corresponds to an implementation manner. The light source device 13 and the liquid crystal display panel 11 are built into the shell 253, and the shell 253 is movable due to the hinge 255, and is connected or linked to the power supply unit 256. The reflective retro-reflective component 5 is arranged between the first connecting part and the second connecting part. The side where the spatial floating image of the power supply unit 256 is formed is called the upper part, and the reflective retro-reflective component 5 is provided on the upper part of the power supply unit 256. The reflective retro-reflective component 5 can be bonded to the power supply unit 256, or the reflective retro-reflective component 5 can be fixed by a frame structure and arranged on the upper part of the power supply unit 256. In addition, the power supply unit 256 has, for example, a wireless power supply type battery pack. The power supply unit 256 is connected to the transparent component 100 with a hinge 254. For example, as Fig. 13B As shown, the angle between the power supply unit 256 and the housing 253 is adjusted to about 90 degrees by the hinge 255, and the transparent member 100 is adjusted to contact the end of the housing 253 where the hinge 255 is not installed by the hinge 254. In this case, the light from the light source device 13 is incident on the liquid crystal display panel 11, and the light from the liquid crystal display panel 11 is reflected by the polarization separation member 101 (not shown) provided on the light incident surface of the transparent member 100, and the reflected light is reflected on the reflective retro-reflective member 5, and then transmitted from the transparent member 100 to form a spatial floating image in the air (not shown).

[0090] In addition, based on the power supply unit 256, the transparent member 100 is movably connected to one side of the power supply unit 256 via the second connection unit, and the housing 253 is movably connected to the other side of the power supply unit 256 via the first connection unit. That is, based on the power supply unit 256, the transparent member 100 is movably connected to one side of the power supply unit 256 via the hinge 254, and the housing 253 is movably connected to the other side of the power supply unit 256 via the hinge 255. The end of the power supply unit 256 connected to the transparent member 100 and the end of the power supply unit 256 connected to the housing 253 are opposed. In addition, one end of the housing 253 is connected to the power supply unit 256 via the hinge 255, and the other side of the housing 253 opposite to the end is not connected to the transparent member 100, but when the housing 253 moves to the transparent member 100 side via the hinge 255, it can contact one end side of the transparent member 100. As a result, the transparent component 100 can be fixed at any angle relative to the power supply unit 256, and the transparent component 100 can be moved arbitrarily. When displaying the spatial floating image 3, the other side of the transparent component 100 opposite to the end connected to the hinge 254 can be rotated toward the light emitting side of the retroreflective component 5 with the hinge 254 as the axis. In addition, the other side of the end of the shell 253 connected to the hinge 255 can be rotated toward the side of the spatial floating image with the hinge 255 as the axis. As a result, the imaging position of the spatial floating image can be adjusted to the optimal position and direction facing the observer's line of sight. In addition, the hinge 255 can also be referred to as the first connecting part, and the hinge 254 can be referred to as the second connecting part. The first and second connecting parts may include connecting parts and movable parts.

[0091] In addition, in order to prevent external light, the recognition of the spatial suspended image can be improved by providing side walls on both sides of the space of the triangular prism surrounded by the housing 253, the power supply unit 256 and the transparent member 100. The side walls can be detachable, foldable, or retractable. For example, the side walls can be appropriately arranged at the end of the power supply unit 256 or the housing 253 without a hinge.

[0092] Fig.13D , Fig.13E is with Figure 2 The light source device 13 and the liquid crystal display panel 11 are built into the housing 253, and the housing 253 is movably connected or linked to the power supply unit 256 via a hinge 255. The reflective retro-reflective component 5 is connected to the transparent component 100 via a hinge 254 and is held at a predetermined position by the restraining force of the hinge 254. Fig.13D yes Fig.13E The embodiment shown is a top view, but it is the position of the housing 253 and Fig.13EExample of reverse configuration: In addition, the light source section provided in the housing 253 is drawn as a perspective view, and the configuration of the liquid crystal panel 11, the reflective light guide 306, and the drive circuit 251 is shown.

[0093] Figure 13B to Figure 13E In order to make it easier to move the viewpoint to the end of the transparent component 100 facing the observer, especially the upper part, that is, the end that is not connected or linked to the power supply unit 256 through the hinge 254, a mark is added to the end of the transparent component 100 that is not connected to the power supply unit 256 through the hinge 254. Furthermore, the same mark is added to the side of the transparent component 100, that is, the side of the mark that is not opposite to the retro-reflective component 5, so that the observer's attention is drawn to the mark. It was found that this has the effect of making people feel the suspension amount of the spatially suspended image greater than the actual situation. The metal heat sink (not shown) used to dissipate the heat generated by the LED to the outside is arranged inside the shell and is not exposed. However, the metal heat sink can also be arranged outside the shell.

[0094] When the space floating image is in a non-display state, the angle formed by the housing 253 and the power supply unit 256 is configured to be about 180 degrees, and the transparent component 100 can be folded toward the light emitting side of the liquid crystal display panel 11 built into the housing 253 through the hinge 254. As a result, it becomes the thinnest structure, achieving a portable thickness. In addition, when the space floating image is in a non-display state, the transparent component 100 and the housing 253 that accommodates the image display device can be freely folded toward the opposite side through the hinges 254 and 255. On the other hand, when the other side (i.e., the other opposite end) of the end of the transparent component 100 connected to the hinge 254 is rotated and folded toward the opposite side of the light emitting side of the liquid crystal panel 11, the length of the device can be shortened in the long side direction, but the thickness is increased. In this way, the folding method can be adjusted accordingly according to the needs of the user.

[0095] Fig.13FThe space suspended image display device shown in the figure has a shell that is roughly cylindrical, especially cylindrical. The space suspended image display device with the cylindrical shell is a relatively small (compact) and movable (portable) space suspended image display device of the type of a bottle holder (also called a beverage holder) that can be stored. For example, such a space suspended image display device can be appropriately configured in a bottle holder (also called a beverage holder) or on a dashboard in a vehicle. The cylindrical shape is a shape in which the cylinder axis extends in the height direction (corresponding to the vertical direction) and the diameter of the cylinder extends in a direction orthogonal to it (corresponding to the horizontal direction). The cylindrical shell roughly has an upper shell and a lower shell, which are connected to each other. In addition, the upper shell and the lower shell can be connected as a whole or not. The optical system and the control circuit board are stored inside the shell, and a rechargeable battery is stored as needed.

[0096] Fig.13F Indicates that it is used Figure 2 The structure of the spatial floating image display system of the reflective retro-reflective component 5 shown in other embodiments of the present invention is shown. Fig.13F (1) is a perspective view of a beverage holder type space floating image display system using a reflective retro-reflective component 5, Fig.13F (2) shows a side view of a beverage holder type space floating image display system using a reflective retro-reflective component 5, Fig.13F (3) Fig.13F (4) is a side view showing another example of a beverage holder type space floating image display system using the reflective retroreflective member 5 . Fig.13F (3) Fig.13F The power supply unit is omitted in (4). The spatial suspended image display device of this embodiment includes a power supply unit 256, a reflective retro-reflective component 5, and a housing 253 with an image display device built in. In order to maintain balance, such a beverage holder-type spatial suspended image device arranges the reflective retro-reflective component 5 and the image display device on the upper part of the housing, and arranges the power supply unit 256 on the lower part of the housing. The housing 253 has a light source device 13 and a liquid crystal panel 11 built in. In addition, the spatial suspended image device also includes a transparent component 100.

[0097] In addition, if Fig.13FAs shown, the retroreflective member 5 is disposed obliquely on the support portion 258 with respect to the power supply unit 256. The housing 253 is disposed obliquely with respect to the power supply unit 256. One end portion of the housing 253 is connected to the support portion 258, and the other end portion is movably connected to the transparent member 100 via a hinge 260. In addition, the end portion of the housing 253 connected to the support portion 258 in the present embodiment is referred to as the lower portion, that is, the side of the power supply unit 256, and the end portion of the housing 253 connected to the transparent member 100 via the hinge 260 is referred to as the upper portion. In the vertical direction or the height direction, a recess is formed in the support portion 258, and one end portion of the housing 253 and one end portion of the retroreflective member 5 are fixed to the recess. As Fig.13F shown in (2) of Fig.13F , the support portion 258 has a U-shaped configuration, but is not limited to this shape and may have other shapes according to the design. For example, as Fig.13F shown in (3) of Fig.13F , the support portion may not be U-shaped, but may be separately disposed like the support portion 259a of the housing 253 and the support portion 259b of the retroreflective member 5. The connecting portion between the housing 253 and the retroreflective member 5 may be tightly connected to the housing of the housing 253, or only partially connected. In Fig.13F (1) to (4) of Fig.13F , the angle formed by the housing 253 and the retroreflective member 5 is arranged to be 90 degrees. The display position of the spatial floating image can be adjusted by the position of the transparent member 100, and the transparent member 100 can rotate around the hinge 260 toward the side of the spatial floating image (not shown). In addition, it is also possible to make

[0098] (3) of Fig.13FIn (1), the image light from the image display device built into the housing 253 is reflected by the polarization separation component (not shown) disposed on the light incident surface of the transparent component 100, and the reflected light is reflected on the reflective retro-reflective component 5, and then transmitted from the transparent component 100, forming a spatial suspended image (not shown) in the air on the opposite side of the support portion 258 with the transparent component 100 as a reference. In addition, the support portion 258 can be referred to as a first connecting portion or a first connecting portion, and the hinge 260 can be referred to as a second connecting portion or a first connecting portion. In addition, in order to prevent external light, by providing side walls on both sides of the space of the triangular prism surrounded by the housing 253, the power supply unit 256 and the transparent component 100, the recognizability of the spatial suspended image can be improved. The side wall can be detachable, foldable, or retractable. For example, the side wall can be appropriately arranged at the end of the power supply unit 256 or the housing 253 without a hinge.

[0099] Through the above structure, a space suspended image display system that realizes a miniaturized, portable design and low power consumption can be provided. The space suspended image display system has a display panel for displaying an image and a light source device for the display panel built into the same housing, and a mobile battery and a holding component for holding a reflective retro-reflective component are respectively connected by hinges, wherein the reflective retro-reflective component reflects the image light from the display panel and uses the reflected light to display a space suspended image of a real image in the air. Thus, the system form is changed accordingly according to the usage mode to make it portable, and the power consumption can be greatly reduced by making the directional characteristics of the light source device a narrow-angle characteristic.

[0100] <Image light control sheet>

[0101] In order to make the diffusion characteristics of the vertical direction of the screen and the horizontal direction of the screen different in the above-mentioned image display device 1, an image light control sheet is provided on the image light exit surface of the liquid crystal panel 11. As the image light control sheet, for example, a view angle control film (VCF: View Control Film) of Shin-Etsu Polymer Co., Ltd. is suitable, and its structure is to alternately arrange transparent silicon and black silicon and arrange synthetic resin on the light input and output surfaces to form a sandwich structure, so it is expected to achieve the same effect as the external light control film of this embodiment. At this time, in the view angle control film (VCF), the transparent silicon and black silicon extending in a prescribed direction are arranged alternately, so it can be arranged so that the extending direction of the transparent silicon and black silicon of the image light control sheet 21 is inclined in the up-down direction relative to the arrangement direction of the pixels of the liquid crystal panel 11, thereby reducing the moiré caused by the spacing between the pixels and the external light control film.

[0102] (1) In order to reduce the vertical stripes generated by the transmission part and the light absorption part of the image light control sheet and the moiré generated by the arrangement of the pixels of the liquid crystal panel 11, the vertical stripes and the pixel arrangement can be arranged obliquely. Furthermore, (2) when the pixel size of the liquid crystal panel 11 is A and the pitch of the vertical stripes of the image light control sheet 12 is B, the ratio (B / A) is selected to be a non-integer multiple, which has the effect of further reducing the moiré.

[0103] One pixel of a liquid crystal panel is composed of pixels of three colors, RGB, which are usually arranged in a square shape, so the generation of the above-mentioned moiré cannot be suppressed on the entire screen. Therefore, for the tilted configuration shown in (1), it is found through experiments that it can be optimized in the range of 5 degrees to 25 degrees, so that the position where the moiré is generated is deliberately offset and configured in a place where the spatial floating image is not displayed. In order to reduce the moiré, the liquid crystal panel is used as the basis for explanation, but the moiré generated between the retro-reflective component 2 and the image light control sheet 250 is generated because both are linear structures. Therefore, by optimally tilting the image light control sheet relative to the pixel arrangement of the liquid crystal panel, the coarse moiré with a low frequency that can also be seen by the naked eye can be reduced.

[0104] Image light control sheet 250 Figure 3 As shown, it is configured on the image light emitting surface of the liquid crystal panel 11 and is bonded and fixed to the image light emitting surface of the liquid crystal panel 11 by an adhesive material.

[0105] <Performance of LCD Panel>

[0106] However, in a conventional TFT (Thin Film Transistor) liquid crystal panel, the brightness and contrast performance differ depending on the direction of light emission due to the characteristics of the liquid crystal and the polarizing plate. Fig. 20 In the evaluation under the measurement environment shown in the figure, the characteristics of the brightness and viewing angle in the short side (up and down) direction of the panel are as follows Fig. 22 As shown in FIG. 1 , the characteristics at a slightly deviated angle (+5 degrees in this embodiment) are better than those at an emission angle perpendicular to the panel surface (emission angle 0 degrees). The reason for this is that the characteristics of light twisting in the short side (up and down) direction of the liquid crystal panel are not 0 degrees when the applied voltage is maximum.

[0107] On the other hand, Fig.24 As shown, the contrast performance in the short side (up and down) direction of the panel is excellent in the range of -15 degrees to +15 degrees. Combined with the brightness characteristics, the best characteristics can be obtained by using it in the range of ±10 degrees with 5 degrees as the center.

[0108] In addition, the characteristics of the brightness and viewing angle in the long side (left and right) direction of the panel are as follows Fig.21As shown, the characteristics at the emission angle perpendicular to the panel surface (emission angle 0 degrees) are excellent. The reason is that the characteristic of twisting light on the long side (left-right direction) of the liquid crystal panel is 0 degrees when the applied voltage is the maximum.

[0109] Likewise, Fig.23 As shown, the contrast performance in the long side (left and right) direction of the panel is relatively good in the range of -5 degrees to -10 degrees. In combination with the brightness characteristics, the best characteristics can be obtained by using it in the range of ±5 degrees with -5 degrees as the center. Therefore, regarding the emission angle of the image light emitted from the liquid crystal panel, the light beam direction conversion unit provided in the light guide of the light source device 13 is used to make the light incident on the liquid crystal panel from the direction in which the best characteristics can be obtained, and the light is modulated using the image signal, so that the image quality and performance of the image display device 1 can be improved.

[0110] In order to maximize the brightness and contrast characteristics of the liquid crystal panel as an image display element, the image quality of the spatial floating image can be improved by setting the light incident on the liquid crystal panel from the light source to the above range.

[0111] <Light source light control method>

[0112] In this embodiment, in order to improve the utilization efficiency of the outgoing light beam from the light source device 13 and significantly reduce power consumption, in the image display device 1 composed of the light source device 13 and the liquid crystal display panel 11, the light from the light source device 13 is incident on the liquid crystal panel 11 at the maximum incident angle of the characteristics of the liquid crystal panel 11, and then the image light after brightness modulation according to the image signal is emitted to the retro-reflective component. At this time, in order to miniaturize the device volume of the spatial suspended image display system, it is required to increase the configuration freedom of the liquid crystal panel 11 and the retro-reflective component. Furthermore, in order to form a suspended image at a desired position after retro-reflection and ensure the optimal directivity, the following technical means can be used.

[0113] On the image display surface of the liquid crystal panel 11, a transparent sheet composed of optical components such as a linear Fresnel lens is set as a light direction conversion panel, and the emission direction of the incident light beam incident on the retro-reflective optical component is controlled while giving high directivity, thereby determining the imaging position of the spatial suspended image. According to this structure, the image light from the image display device 1 reaches the observer efficiently with high directivity (straight line travel) like a laser, and as a result, a high-quality suspended image can be displayed with high resolution, and the power consumption of the image display device 1 including the light source device 13 is greatly reduced.

[0114] <Example 1 of video display device>

[0115] Fig.16AAnother example of the specific structure of the image display device 1 is shown. The light source device 13 is composed of, for example, a plastic housing that contains an LED, a collimator, a synthetic diffusion block, a light guide, etc., and a liquid crystal display panel 11 is mounted on its upper surface. In addition, an LED circuit board is mounted on one side of the housing of the light source device 13, and a heat sink (not shown) that is a component for cooling the heat generated by the LED element and the control circuit is mounted on the outer surface of the LED circuit board, wherein an LED (Light Emitting Diode) element 14b as a semiconductor light source and its control circuit are mounted on the LED circuit board.

[0116] In addition, a liquid crystal display panel frame mounted on the upper surface of the housing is provided with a liquid crystal display panel 11 mounted on the frame and an FPC (Flexible Printed Circuits) (not shown) electrically connected to the liquid crystal display panel 11. That is, the liquid crystal display element, i.e., the liquid crystal display panel 11, together with the LED element 14b as a solid light source, modulates the intensity of the transmitted light based on a control signal of a control circuit (not shown here) constituting the electronic device, thereby generating a display image.

[0117] <Example 1 of light source device of Example 1 of image display device>

[0118] Next, for the structure of the optical system such as the light source device housed in the box, refer to Fig.16A as well as Fig. 16B The details are explained below. Fig.16A and Fig. 16B 14b, which constitute the light source 13, are installed at predetermined positions relative to the collimator 18. The collimator 18 is formed of a light-transmitting material such as glass or a heat-resistant resin. Fig. 16B As shown, it has an outer peripheral surface 156 of a conical convex shape obtained by rotating a parabola section, and has a concave portion 153 in the center of the top (the side in contact with the LED circuit board), and a convex portion (ie, a convex lens surface) 157 is formed in the concave portion 153.

[0119] In addition, a convex lens surface (or a concave lens surface recessed inwardly) 154 is provided at the center of the flat surface (opposite to the top) of the collimator 18. In addition, the parabola 156 forming the outer peripheral surface of the conical shape of the collimator 15 is set within an angle range that allows the light emitted from the LED elements 14 and 14b in the peripheral direction to be totally reflected inside it, or forms a reflecting surface.

[0120] LEDs 14 and 14b are disposed at predetermined positions on the surface of substrate 102, which is a circuit board. Substrate 102 is disposed and fixed to collimator 18 so that LEDs 14 and 14b on the surface are located at the center of recess 153.

[0121] According to this structure, under the action of the above-mentioned collimator 18, the light emitted from the LED 14 or 14b, especially the light emitted from the central part thereof to the upper side (to the right in the figure), is converged by the two convex lens surfaces 157 and 154 forming the outer shape of the collimator 18 to become parallel light. In addition, the light emitted from other parts to the peripheral direction is reflected by the parabola forming the outer peripheral surface of the conical shape of the collimator 18, and is also converged to become parallel light. In other words, by using the collimator 18 having a convex lens in its central part and a parabola formed in its peripheral part, almost all of the light generated from the LED 14 or 14b can be output as parallel light, which can improve the utilization efficiency of the generated light.

[0122] In addition, a polarization conversion element 21 is provided on the light exit side of the collimator 18. The polarization conversion element 21 may also be referred to as a polarization conversion component. Fig. 16B It can be seen that the polarization conversion element 21 is composed of a combination of a light-transmitting member having a parallelogram-shaped column (hereinafter referred to as a parallelogram column) and a light-transmitting member having a triangular column (hereinafter referred to as a triangular column) in cross section, and a plurality of light-transmitting members are arranged in parallel in an array on a plane orthogonal to the optical axis of the parallel light from the collimator 18. Furthermore, polarization beam splitters (hereinafter referred to as "PBS films") and reflective films are alternately provided on the interface between adjacent light-transmitting members arranged in the array, and a λ / 2 phase plate is provided on the exit surface from which light incident on the polarization conversion element 21 and transmitted through the PBS film is emitted.

[0123] <Directional characteristics of light emitted from a liquid crystal panel>

[0124] Regarding the light emitted from the liquid crystal display panel 11, in a general TV-use device, for example Fig.19 (A) "Existing characteristics (X direction)" and Fig.19 As shown in the plotted curve of "Existing Characteristics (Y Direction)" in (B), in the horizontal direction of the screen (with Fig.19 The X-axis of the graph (A) corresponds to the display direction) and the vertical direction of the screen (with Fig.19 The Y-axis of the graph of (B) corresponds to the display direction) and has the same diffusion characteristics as each other.

[0125] In contrast, the diffusion characteristics of the outgoing light beam from the liquid crystal display panel of this embodiment are, for example, Fig.19 (A) in "Example 1 (X direction)" and Fig.19The diffusion characteristics of the plotted curve of "Example 1 (Y direction)" in (B) are shown.

[0126] In a specific example, when the viewing angle is set to 13 degrees when the brightness is reduced to 50% brightness (reduced to about half the brightness) relative to the front view (angle 0 degrees), this is about 1 / 5 of the diffusion characteristics of a device for general home TV use (angle 62 degrees). Similarly, in an example where the viewing angle in the vertical direction is set to be uneven on the upper and lower sides, the reflection angle of the reflective light guide, the area of ​​the reflection surface, etc. are optimized in such a way that the viewing angle on the upper side is suppressed (narrowed) to about 1 / 3 relative to the viewing angle on the lower side.

[0127] By setting the viewing angle and the like as described above, the amount of image light in the direction of viewing of the user is greatly increased (the brightness of the image is greatly improved) compared to conventional liquid crystal TVs, and the brightness of the image is more than 50 times.

[0128] Furthermore, in adopting Fig.19 In the case of the viewing angle characteristics shown in "Example 2", the viewing angle is 5 degrees when the brightness of the image obtained by front viewing (angle 0 degrees) drops to 50% brightness (reduced to about half the brightness), which is about 1 / 12 of the diffusion characteristics of the device for ordinary home TV use (angle 62 degrees) (narrower viewing angle). Similarly, in an example where the vertical viewing angle is set to be uniform on the upper and lower sides, the reflection angle of the reflective light guide, the area of ​​the reflection surface, etc. are optimized in such a way that the vertical viewing angle is suppressed (narrowed) to about 1 / 12 of the existing one.

[0129] By making such a setting, the brightness (amount of light) of the image in the viewing direction (the direction of the user's line of sight) is greatly improved compared to the existing LCD TV, and the brightness of the image is more than 100 times.

[0130] As described above, by making the viewing angle narrow, the amount of light beams going in the viewing direction can be concentrated, so the light utilization efficiency is greatly improved. As a result, even if a liquid crystal display panel for TV use is used, the brightness can be greatly improved with the same power consumption by adjusting the light diffusion characteristics of the light source device, and it can become an image display device that supports a display system that displays to bright outdoor areas.

[0131] When a large liquid crystal display panel is used, the light around the screen is directed inwards to the direction of the observer when the observer is facing the center of the screen, thereby improving the overall brightness of the screen. On the other hand, when the panel size (screen ratio 16:10) of the image display device is less than 5 inches and the vertical placement mentioned in this embodiment is adopted (the screen of the liquid crystal display panel is made longer vertically (hereinafter also referred to as "vertical use")), the horizontal directional characteristics can also be greatly narrowed to achieve a high-brightness or low-power spatial floating image display device.

[0132] A plurality of other examples of the light source device will be described below. These other examples of the light source device can be used instead of the light source device of the example of the image display device described above.

[0133] When a large liquid crystal display panel is used, as described above, the light around the screen is directed inward when the observer is facing the center of the screen so that it goes in the direction of the observer, thereby improving the comprehensiveness of the screen brightness. However, on the other hand, binocular parallax will occur depending on which eye the observer uses to watch. In addition, the smaller the panel size and the closer the viewing distance, the greater the convergence angle under the binocular vision of the left and right eyes. In particular, when a small panel of less than 7 inches is used, the convergence angle determined by binocular parallax is an important condition, so it can be designed to expand the light diffusion characteristics of the light source or make it have directional characteristics so that the image light goes to the optimal viewing range of the system.

[0134] Furthermore, depending on the required specifications of the system, in order to obtain horizontal and vertical directional characteristics and diffusion characteristics, the shape, surface roughness, inclination, etc. of the reflective surface of the light guide of the above-mentioned light source device 13 need to be optimized.

[0135] <Example 1 of light source device>

[0136] Next, refer to Fig.14 Another example of the light source device will be described. Fig.14 (a) and (b) are diagrams in which a portion of the liquid crystal display panel 11 and the diffusion plate 206 are omitted for the purpose of explaining the light guide 311 .

[0137] Fig.14 The LED 14 constituting the light source is shown in a state mounted on the substrate 102. The LED 14 and the substrate 102 are mounted at predetermined positions with respect to the reflector 300.

[0138] like Fig.14As shown, the LEDs 14 are arranged in a row in a direction parallel to the side (the short side in this example) of the liquid crystal display panel 11 on the side where the reflector 300 is arranged. In the example shown in the figure, the reflector 300 is arranged corresponding to the arrangement of the LEDs. In addition, a plurality of reflectors 300 may be arranged.

[0139] In a specific example, each of the reflectors 300 is formed of a plastic material. As another example, the reflectors 300 may also be formed of a metal material or a glass material, but plastic material is easier to shape, so plastic material is used in this embodiment.

[0140] like Fig.14 As shown in (b), the inner side (right side in the figure) of the reflector 300 has a reflecting surface (hereinafter sometimes referred to as a "parabola") 305 in a shape obtained by cutting a parabola with a meridian plane. The reflector 300 transforms the divergent light emitted from the LED 14 into approximately parallel light by reflecting it on the above-mentioned reflecting surface 305 (parabola), and causes the transformed light to be incident on the end face of the light guide 311. In addition to the aluminum reflective film, a multilayer of metal film such as Ti and SiO is formed on the reflective surface of the reflector 300 as a reflection enhancement film, forming a design that improves the reflectivity and reduces the incidence angle dependence. In a specific example, the light guide 311 is a reflective light guide.

[0141] The reflecting surface of the reflector 300 is asymmetrical with respect to the optical axis of the emitted light of the LED 14. The reflecting surface 321 of the reflector 300 is a parabola as described above, and by arranging the LED at the focus of the parabola, the reflected light beam is converted into substantially parallel light.

[0142] Since LED 14 is a surface light source, even if it is arranged at the focus of the parabola, the divergent light from the LED cannot be converted into completely parallel light, but this does not affect the performance of the light source of the present invention. LED 14 and reflector 300 form a pair, and in order to ensure the specified performance under the mounting accuracy of LED 14 on substrate 102 of ±40μm, the number of LEDs mounted on the substrate should be less than 10 at most, and can be suppressed to about 5 in consideration of mass production.

[0143] Although the LED 14 and the reflector 300 are very close to each other in a part, the temperature rise of the LED can be reduced because heat can be dissipated to the space on the opening side of the reflector 300. Therefore, a plastic molded reflector 300 can be used. As a result, the shape accuracy of the reflecting surface can be improved by more than 10 times compared with a reflector made of glass material by using the reflector 300, so the light utilization efficiency can be improved.

[0144] On the other hand, Fig.14As shown in FIG. 1 , a reflective surface is provided on the bottom surface 303 of the light guide 311. After the light from the LED 14 is converted into a parallel light beam by the reflector 300, it is reflected on the reflective surface and emitted toward the liquid crystal display panel 11 arranged opposite to the light guide 311. Fig.14 As shown, in the traveling direction of the parallel light beam from the reflector 300, reflection occurs on multiple surfaces with different inclinations and goes to the corresponding liquid crystal panel parts respectively. Each of the multiple surfaces with different inclinations can have a shape extending in a direction perpendicular to the traveling direction of the parallel light beam from the reflector 300.

[0145] In addition, if Fig.14 As shown, the shape of the reflective surface provided on the bottom surface 303 may also be a plane shape. Furthermore, in order to more accurately control the diffusion characteristics of the light reflected by the reflective surface provided on the bottom surface 303 of the light guide 311 opposite to the liquid crystal display panel 11, a diffuser 206 may also be provided. The diffuser can adjust the amount of light and the emission direction of the light beam that makes the above-mentioned reflected light refracted before going to the liquid crystal display panel 11 with high accuracy through the surface shape and surface roughness of both sides, so the amount of light and the emission direction of the incident light incident on the liquid crystal display panel 11 and the outgoing light emitted from the liquid crystal display panel 11 can be controlled with the same high accuracy. Therefore, in the spatial suspended image display system using the image display device 1 of the above structure, the diffusion direction and diffusion angle of the image light of the spatial suspended image can be set to the required value. At this time, for the reflective film provided on the reflective surface, a design with high reflectivity and reduced incidence angle dependence of the reflectivity can also be formed by adding a Ti or SiO anti-reflection film in addition to the aluminum reflective film. In the aluminum reflective film described above, the reflectivity of the blue-green band below 500nm is lower than that of the green-red band. Therefore, in the design of the anti-reflection film, in order to reduce the incident angle dependence of the reflectivity and improve color reproduction, it is also important to improve the purity of white.

[0146] like Fig.14 As shown, LED 14 is soldered on a metallic substrate 102. Therefore, the heat generated by the LED can be dissipated into the air through the substrate. In addition, the reflector 300 can be in contact with the substrate 102 or separated by a space. In the case of a space, the reflector 300 is bonded and arranged on the housing. By separating the space, the heat generated by the LED can be dissipated into the air, and the cooling effect is improved. As a result, the operating temperature of the LED can be reduced, so the luminous efficiency can be maintained and the life span can be extended.

[0147] In the light source device described above, the light utilization efficiency can be increased by 1.8 times by using the polarization conversion element 21. Fig.15A , Fig. 15B , Fig. 15C and Fig.15D The structure of the optical system of the light source device will be described in detail.

[0148] Fig.15A , Fig. 15B and Fig. 15C The LED 14 constituting the light source is shown mounted on the substrate 102 , and the reflector 300 and the LED 14 are regarded as a pair of modules, and the unit 312 includes a plurality of modules.

[0149] in, Fig.15A The base material 320 shown in (2) is the base material of the substrate 102. Generally, the metallic substrate 102 has heat, so in order to insulate the heat of the substrate 102 (heat insulation), a plastic material or the like may be used for the base material 320. A metal component may also be used to improve heat dissipation.

[0150] In addition, the reflective surface 321 of the reflector 300 may be in an asymmetric shape with respect to the optical axis of the emitted light of the LED 14. Fig.15A The reason is described in (2). In this embodiment, the reflecting surface of the reflector 300 is a parabola, and the center of the light emitting surface of the surface light source, ie, the LED, is arranged at the focal position of the parabola.

[0151] In addition, due to the characteristics of the parabola, the light from the four corners of the light-emitting surface also becomes a substantially parallel beam, and only the emission direction is different. Therefore, even if the light-emitting portion has an area, if the interval between the polarization conversion element and the reflector 300 arranged in the later stage is short, the amount of light incident on the polarization conversion element 21 and the conversion efficiency are almost not affected.

[0152] In addition, an optical system can be realized: even if the installation position of LED 14 is offset in the XY plane relative to the focus of the corresponding reflector 300, the reduction in light conversion efficiency can be reduced for the above reasons. Furthermore, even if the installation position of LED 14 deviates (fluctuates) in the Z-axis direction, the result in this case is only that the converted parallel light beam moves in the ZX plane, which can greatly relax the installation accuracy of the surface light source, i.e., LED. The reflector 300 described in this embodiment has a reflecting surface obtained by cutting off a part of the parabola along the meridian direction, but the entire parabola can also be used as a reflecting surface and the LED can be arranged on the cut part.

[0153] On the other hand, the characteristic structure of this embodiment is as follows Fig. 15B (1) Fig. 15C As shown, the divergent light from LED 14 is reflected on the parabola 321 and converted into approximately parallel light, which is then incident on the end face of the polarization conversion element 21 at the subsequent stage and is unified into a specific polarization by the polarization conversion element 21. With this characteristic structure, the light utilization efficiency of this embodiment is higher than that of the above-mentioned Fig.14In this example, the efficiency is increased by 1.8 times, which enables a highly efficient light source.

[0154] In addition, the substantially parallel light reflected from the parabola 321 by the divergent light from the LED 14 is not uniform. Therefore, by using the reflective surface 307 with various inclinations to adjust the angular distribution of the reflected light, the reflected light can be incident on the liquid crystal display panel 11 in a direction perpendicular to the liquid crystal display panel 11.

[0155] Here, in the example of this figure, the direction of light (main light) entering the reflector from the LED is roughly parallel to the direction of light entering the liquid crystal display panel. This configuration is easy to configure from a design point of view, and when the heat source is arranged under the light source device, air is exhausted upward, so the temperature rise of the LED can be reduced, so it is preferred.

[0156] In addition, if Fig. 15B As shown in (1), in order to improve the capture rate of the divergent light emitted from the LED 14, a sub-reflector 308 provided on a light shielding plate 309 disposed on the upper part of the reflector is used to reflect the light beam that has not been captured by the reflector 300, and reflect it on the inclined surface of the lower sub-reflector 310, and enter the effective area of ​​the subsequent polarization conversion element 21, thereby further improving the light utilization efficiency. That is, in this embodiment, a part of the light reflected by the reflector 300 is reflected on the sub-reflector 308, and the light reflected on the sub-reflector 308 is reflected by the sub-reflector 310 in the direction of the light guide 306.

[0157] By using the reflective shape provided on the surface of the reflective light guide 306, the substantially parallel light beams uniformly polarized by the polarization conversion element 21 are reflected toward the liquid crystal display panel 11 arranged opposite to the light guide 306. At this time, the light quantity distribution of the light beam incident on the liquid crystal display panel 11 can be optimally designed by the shape and arrangement of the reflector 300, the shape (cross-sectional shape) of the reflective surface of the reflective light guide, and the inclination and surface roughness of the reflective surface.

[0158] As the shape of the reflective surface set on the surface of the light guide 306, multiple reflective surfaces are arranged opposite to the output surface of the polarization conversion element. The inclination, area, height and spacing of the reflective surface are optimized accordingly according to the distance between the polarization conversion element 21, so that the light amount distribution of the light beam incident on the liquid crystal display panel 11 becomes the required value as described above.

[0159] The reflective surface 307 provided on the reflective light guide 306 is as follows: Fig. 15B As shown in (2) of FIG. 1 , by adopting a structure having multiple inclinations on one surface, the adjustment of the reflected light can be achieved with higher precision. Fig. 15B As shown in (2), the parallel light beam from the reflector 300 5 (R7 to R10) is reflected by multiple surfaces (P7 to P10) with different inclinations in its traveling direction and goes to the corresponding liquid crystal panel parts respectively. In addition, in a structure having multiple inclinations on one surface of the reflection surface, the area used as the reflection surface can be multiple surfaces or multiple surfaces or curved surfaces. Furthermore, a more uniform light quantity distribution can be achieved by the diffusion effect of the diffusion plate 206. For the light incident on the diffusion plate on the side close to the LED, a uniform light quantity distribution can be achieved by changing the inclination of the reflection surface. As a result, the light quantity and emission direction of the light beam going to the liquid crystal display panel 11 can be adjusted with high precision. As a result, the light quantity and emission direction of the incident light incident on the liquid crystal display panel 11 and the emission light emitted from the liquid crystal display panel 11 can be controlled with the same high precision, so in the space floating image display system using the image display device 1, the diffusion direction and diffusion angle of the image light of the space floating image can be set to the required value.

[0160] In this embodiment, a plastic material such as heat-resistant polycarbonate is used as the base material of the reflection surface 307. In addition, the angle of the reflection surface 307 immediately after the light exits the λ / 2 plate 213 changes depending on the distance between the λ / 2 plate and the reflection surface.

[0161] In this embodiment, the LED 14 and the reflector 300 are also partially close, but the heat can be dissipated to the space on the opening side of the reflector 300, which can reduce the temperature rise of the LED. Fig.15A , Fig. 15B , Fig. 15C The substrate 102 and the reflector 300 are arranged upside down.

[0162] However, when the substrate 102 is arranged at the top, the substrate 102 is close to the liquid crystal display panel 11, so it is difficult to lay out. Therefore, when the substrate 102 is arranged at the lower side of the reflector 300 (the side farther from the liquid crystal display panel 11) as shown in the figure, the structure in the device is simpler.

[0163] On the light incident surface of the polarization conversion element 21, a shading plate 410 can be provided to prevent useless light from entering the subsequent optical system. By adopting such a structure, a light source device that suppresses temperature rise can be realized. For the polarizer disposed on the light incident surface of the liquid crystal display panel 11, the uniformly polarized light beam of the present invention can reduce the temperature rise caused by absorption, but the polarization direction will rotate when reflected on the reflective light guide, and a part of the light will be absorbed by the incident side polarizer. Furthermore, the temperature of the liquid crystal display panel 11 will also rise due to the absorption of the liquid crystal itself and the temperature rise caused by the light incident on the electrode pattern, but there is sufficient space between the reflective surface of the reflective light guide 306 and the liquid crystal display panel 11, which can be cooled naturally.

[0164] Fig.15D yes Fig. 15B (1) and Fig. 15C A modified example of the light source device. Fig.15D (1) selected Fig. 15B The modified example is shown as a part of the light source device of (1). Fig. 15B The structure of the light source device in (1) is the same as that in the above-mentioned light source device, so illustration and repeated description are omitted.

[0165] First, in Fig.15D In the example shown in (1), the height of the concave portion 319 of the sub-reflector 310 is adjusted to be lower than the fluorescent body 114 so that the main light of the fluorescent light output from the fluorescent body 114 in the horizontal direction (X-axis direction) (refer to Fig.15D The straight line extending in the direction parallel to the X-axis in (1) can pass through the recessed portion 319 of the sub-reflector 310. Furthermore, the height of the light shielding plate 410 in the Z-axis direction is adjusted to be lower than the position of the fluorescent body 114 so that the main light of the fluorescent light output laterally from the fluorescent body 114 is not blocked by the light shielding plate 410 and enters the effective area of ​​the polarization conversion element 21.

[0166] In addition, the light reflected by the sub-reflector 308 is reflected by the reflective surface of the concavo-convex convex portion of the top of the sub-reflector 310, so that the light reflected by the sub-reflector 308 is guided to the light guide 306. Thus, by adjusting the height of the convex portion 318 of the sub-reflector 310 so that the light reflected by the sub-reflector 308 can be reflected and incident on the effective area of ​​the polarization conversion element 21 at the subsequent stage, the light utilization efficiency can be further improved.

[0167] In addition, the sub-reflector 310 is as follows Fig.15A As shown in (2), the sub-reflector 310 is configured to extend in one direction and have a concavo-convex shape. Furthermore, at the top of the sub-reflector 310, concavo-convex shapes are periodically arranged along one direction, wherein there are one or more concave portions 319 and convex portions 318. By adopting such a concavo-convex shape, it is possible to configure so that the main light of the fluorescence output laterally from the fluorescent body 114 is incident on the effective area of ​​the polarization conversion element 21.

[0168] In addition, the concavo-convex shape of the sub-reflector 310 satisfies that the concave portion 319 is located at the position where the LED 14 is located, and is periodically arranged at such a pitch. That is, the phosphor 114 is periodically arranged along one direction corresponding to the arrangement pitch of the concave portions in the concavo-convex shape of the sub-reflector 310. In addition, when the LED 14 has the phosphor 114, the phosphor 114 can also be described as the light-emitting portion of the light source.

[0169] in addition, Fig.15D (2) selected Fig. 15CAs for the other structures, since it is similar to Fig. 15C Since the structure is the same as the light source device of FIG. 1 , illustration and repeated description are omitted. Fig.15D As shown in (2), there may be no sub-reflector 310, but Fig.15D (1) Similarly, the height of the light shielding plate 410 in the Z-axis direction is adjusted to be lower than the position of the fluorescent body 114 so that the principal light of the fluorescent light output laterally from the fluorescent body 114 is not blocked by the light shielding plate 410 and enters the effective area of ​​the polarization conversion element 21.

[0170] In addition, about Fig.15A , Fig. 15B , Fig. 15C , Fig.15D Light source device, such as Fig.15A As shown in (1), in order to prevent foreign matter from entering the space between the reflective surface of the reflective light guide 306 and the liquid crystal display panel 11, to prevent stray light from being generated to the outside of the light source device, and to prevent stray light from invading from the outside of the light source device, a side wall 400 may also be provided. When the side wall 400 is provided, it is configured in a manner to sandwich the space between the light guide 306 and the diffuser 206.

[0171] The polarization-converted light is emitted from the polarization conversion element 21, and the light output surface of the polarization conversion element 21 that emits the light faces the space surrounded by the side wall 400, the light guide 306, the diffuser 206, and the polarization conversion element 21. In addition, the space ( Fig. 15B The surface of the portion covered by the space on the right side of the exit surface of the polarization conversion element 21 (1) is a reflective surface having a reflective film or the like. That is, the surface of the side wall 400 facing the above space includes a reflective area having a reflective film. By making this portion of the inner surface of the side wall 400 a reflective surface, the light reflected on the reflective surface can be reused as light source light, which can improve the brightness of the light source device.

[0172] The surface of the inner side of the side wall 400, which covers the polarization conversion element 21 from the side, adopts a surface with low light reflectivity (such as 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, which will cause stray light. In other words, by making the above-mentioned surface a surface with low light reflectivity, stray light that generates images and light with an unexpected polarization state can be prevented or suppressed. In addition, it can also be configured to improve the cooling effect by providing a hole for air circulation in a part of the side wall 400.

[0173] In addition, for Fig.15A , Fig. 15B , Fig. 15C , Fig.15D The light source devices of the present invention have been described on the premise of using the polarization conversion element 21. However, the polarization conversion element 21 may be omitted from these light source devices. In this case, the light source device can be provided at a lower cost.

[0174] <Other example 2 of light source device>

[0175] Next, refer to Fig.16A (1), (2), (3) and Fig. 16B , a detailed description is given of the optical system structure of a light source device using a reflective light guide 304 based on the light source device shown in Example 1 of the light source device.

[0176] Fig.16A The LED 14 constituting the light source is mounted on the substrate 102, and the collimator 18 and the LED 14 are regarded as a pair of modules, and are composed of a unit 328 having multiple modules. The collimator 18 of this embodiment is close to the LED 14, so a glass material is used in consideration of heat resistance. In addition, by providing a shading plate 317 at the front stage of the incident polarization conversion element 21, it is possible to prevent or suppress the incident of useless light to the optical system of the rear stage, and reduce the temperature rise caused by the useless light.

[0177] Fig.16A The other structures and effects of the light sources shown are due to Fig.15A , Fig. 15B , Fig. 15C , Fig.15D Likewise, repeated descriptions are omitted. Fig.15A The light source device and Fig.15A , Fig. 15B , Fig. 15C As described in the above, side walls may also be provided. The structure and effect of the side walls are the same as those already described, so repeated description is omitted.

[0178] Fig. 16B yes Fig.16A The cross-sectional view of (2). Fig. 16B The structure of the light source shown has been described in "Example 1 of light source device in Example 1 of image display device", and therefore repeated description is omitted.

[0179] <Diffuser Plate Structure>

[0180] Fig.17206 is a cross-sectional view showing an example of the shape of the diffuser 206. As described above, the divergent light output from the LED is converted into substantially parallel light by the reflector 300 or the collimator 18, and then converted into a specific polarization by the polarization conversion element 21 and reflected by the light guide. Then, the light beam reflected by the light guide passes through the flat portion of the incident surface of the diffuser 206 and enters the liquid crystal display panel 11 (see FIG. 20). Fig.17 ) The two solid arrows in the figure represent “reflected light from the light guide”.

[0181] In addition, the divergent light beam in the light emitted from the polarization conversion element 21 is totally reflected on the inclined surface of the protrusion having an inclined surface provided on the incident surface of the diffuser 206, and then enters the liquid crystal display panel 11. In order to make the light emitted from the polarization conversion element 21 totally reflected on the inclined surface of the protrusion of the diffuser 206, the angle of the inclined surface of the protrusion is changed based on the distance from the polarization conversion element 21. When the angle of the inclined surface of the protrusion farther from the polarization conversion element 21 or farther from the LED is α, and the angle of the inclined surface of the protrusion closer to the polarization conversion element 21 or closer to the LED is α', α is less than α' (α<α'). By adopting such a setting, the light beam after polarization conversion can be effectively used.

[0182] <Diffusion characteristics control technology for image display devices>

[0183] As a method for adjusting the diffusion distribution of the image light from the liquid crystal display panel 11, a cylindrical lens can be provided between the light source device 13 and the liquid crystal display panel 11 or on the surface of the liquid crystal display panel 11, and the shape of the lens can be optimized. That is, by optimizing the shape of the cylindrical lens, the emission characteristics of the image light (hereinafter also referred to as "image light beam") emitted in one direction from the liquid crystal display panel 11 can be adjusted.

[0184] Alternatively or additionally, a microlens array may be arranged in a matrix on the surface of the liquid crystal display panel 11 (or between the light source device 13 and the liquid crystal display panel 11), and the arrangement pattern may be adjusted. That is, by adjusting the arrangement of the microlens array, the emission characteristics of the image light beam emitted from the image display device 1 in the X-axis and Y-axis directions can be adjusted, so that an image display device with a desired diffusion characteristic can be obtained.

[0185] As another structural example, two cylindrical lenses may be combined and arranged at the position where the image light emitted from the image display device 1 passes, or a microlens array may be arranged in a matrix to set a sheet for adjusting diffusion characteristics. By adopting such an optical system structure, the brightness (relative brightness) of the image light can be adjusted accordingly in the X-axis and Y-axis directions according to the reflection angle of the image light (the reflection angle based on the case of reflection in the vertical direction (0 degrees)).

[0186] In this embodiment, by using such a cylindrical lens, it is possible to Fig.18 As shown in the graphs (plotted curves) of "Example 1 (Y direction)" and "Example 2 (Y direction)" in (b), excellent optical characteristics that are significantly different from the graphs (plotted curves) of existing characteristics are obtained. Specifically, in the plotted curves of Example 1 (Y direction) and Example 2 (Y direction), by making the brightness characteristics in the vertical direction steeper and thereby changing the balance of the directional characteristics in the up and down directions (positive and negative directions of the Y axis), the brightness (relative brightness) of the reflected and diffused light can be increased.

[0187] Therefore, according to the present embodiment, it is possible to adjust the image light to have a narrow diffusion angle (high linear propagation) and only a specific polarization component, like the image light from a surface-emitting laser image source, thereby suppressing the ghost images generated in the retroreflective component when using the image display device of the prior art, and allowing the spatial suspended image formed by retroreflection to efficiently reach the observer's eyes.

[0188] In addition, using the above light source device, Fig.19 Compared with the outgoing light diffusion characteristics of the conventional liquid crystal display panel shown in (A) and (B) (referred to as "existing characteristics" in the figure), it is possible to have very narrow-angle directional characteristics in both the X-axis direction and the Y-axis direction. In this embodiment, by having such narrow-angle directional characteristics, it is possible to realize an image display device that emits nearly parallel image beams in a specific direction and emits light of a specific polarization.

[0189] Fig.18 An example of the characteristics of the cylindrical lens used in this embodiment is shown. In this example, the characteristics in the X direction (vertical direction) based on the Z axis are particularly shown, and the characteristic O represents the vertically symmetrical brightness characteristics with the peak of the light emission direction being approximately 30 degrees above the vertical direction (0 degrees). In addition, Fig.18 The plotted curves of characteristic A and characteristic B shown in the graph further show an example of a characteristic that converges the image light above the peak brightness near 30 degrees to increase the brightness (relative brightness). Therefore, compared with the plotted curve of characteristic O, it can be seen that in characteristic A and characteristic B, the brightness (relative brightness) of light drops sharply in the area where the inclination (angle θ) from the Z axis to the X direction exceeds 30 degrees (θ>30°).

[0190] That is, according to the optical system including the above-mentioned cylindrical lens, when the image light beam from the image display device 1 is incident on the retro-reflective component, the emission angle and the viewing angle of the image light that is unified into a narrow angle by the light source device 13 can be adjusted, and the freedom of setting the retro-reflective sheet can be greatly improved. As a result, the freedom of the relationship between the imaging position of the spatial suspended image that is reflected or transmitted on the window glass and imaged at the required position can be greatly improved. As a result, light with a narrow diffusion angle (high straight-line propagation) and only a specific polarization component can reach the eyes of the observer outdoors or indoors with good efficiency. Therefore, even if the intensity (brightness) of the image light from the image display device 1 is reduced, the observer can correctly identify the image light and obtain information. In other words, by reducing the output of the image display device 1, a display system with low power consumption can be realized.

[0191] Various embodiments or examples (i.e., specific examples) to which the present invention is applied are described in detail above. On the other hand, the present invention is not limited to the above-mentioned embodiments (specific examples), and includes various modified examples. For example, the above-mentioned embodiments describe the entire system in detail in order to explain the present invention in an easy-to-understand manner, but are not limited to all the structures described. In addition, a part of the structure of a certain embodiment can be replaced with the structure of another embodiment, and the structure of another embodiment can be added to the structure of a certain embodiment. In addition, for a part of the structure of each embodiment, other structures can be added, deleted, or replaced.

[0192] The light source device described above is not limited to the spatial floating image display device, but can also be applied to display devices such as HUD, tablet, digital signage, etc.

[0193] In the technology of this embodiment, by making a high-resolution and high-brightness image suspended in space as a space-suspended image, for example, a user can operate without feeling uneasy about the contact transmission of infectious diseases. If the technology of this embodiment is used in a system used by an uncertain number of users, the risk of contact transmission of infectious diseases can be reduced, and a contactless user interface that can be used without feeling uneasy is provided. The present invention that provides such a technology contributes to the "3 Good Health and Well-Being" of the Sustainable Development Goals (SDGs) advocated by the United Nations.

[0194] In addition, in the technology of the above-mentioned embodiment, by reducing the divergence angle of the emitted image light and unifying it into a specific polarization, only the normal reflected light is efficiently reflected to the retro-reflective component, so the light utilization efficiency is high, and a bright and clear spatial floating image can be obtained. According to the technology of this embodiment, a non-contact user interface with excellent usability that can significantly reduce power consumption can be provided. According to the present invention that provides such technology, it contributes to the "9 industries, innovations and infrastructure" and "11 sustainable cities and communities" of the Sustainable Development Goals (SDGs: Sustainable Development Goals) advocated by the United Nations.

[0195] Furthermore, the technology of the above-mentioned embodiment can form a spatial floating image formed by image light with high directivity (straight travel). The technology of this embodiment 5 can provide a non-contact user interface with low risk of spatial floating images being peeped by people other than the user by displaying image light with high directivity when displaying images requiring high security in bank ATMs or ticket machines at stations, or when displaying highly confidential images that are to be kept secret from people facing the user. The present invention contributes to the "11 Sustainable Cities and Communities" of the Sustainable Development Goals (SDGs) advocated by the United Nations by providing the above-mentioned technology.

[0196] Description of Reference Numerals

[0197] 1...image display device, 2...transmissive retro-reflective component, 3...spatial image (spatial suspended image), 3a, 3b...ghost image, 100...transmissive plate, 13...light source device, 250...light control sheet, 251...circuit board, 249...FPC, 252...frame structure, 256...power supply unit (mobile battery), 253...housing, 254...hinge (rotation mechanism), 102...substrate, 11...liquid crystal display panel, 206...diffuser plate, 21...polarization conversion element, 300...reflector, 213...λ / 2 plate, 306...reflective light guide, 308, 310...sub-reflectors.

Claims

1. A spatial suspended image display system, characterized in that: include: a housing that holds the display panel and the light source device; A power supply unit having a power supply and connected to the housing via a first connection portion; and The frame structure holds the retroreflective component and is movably connected to the housing via a second connection portion.

2. The spatial suspended image display system according to claim 1, wherein: The housing and the power supply unit are movably connected via the first connection portion.

3. The spatial suspended image display system according to claim 1, wherein: The retro-reflective component is a transmissive retro-reflective component.

4. A spatial suspended image display system, characterized in that: include: A housing that accommodates the display panel and the light source device; A power supply unit, comprising a power supply and connected to the housing via a first connection portion; a transparent component connected to the power supply unit via a second connecting portion; and The retro-reflective component is arranged on the upper part of the power supply unit.

5. The spatial suspended image display system according to claim 4, characterized in that: The housing and the power supply unit are movably connected via the first connection unit. The power supply unit and the transparent member are movably connected via the second connection portion.

6. The spatial suspended image display system according to claim 4, characterized in that: The retro-reflective component is a reflective retro-reflective component.

7. A spatial suspended image display system, characterized in that: The light source device and the display panel for displaying images are housed in the housing. A structure in which a retro-reflective component is held by a frame structure, wherein the retro-reflective component reflects image light from the display panel and uses the reflected light to display a real image in the air. The frame structure is connected to the shell by a connecting portion. Furthermore, the structure is such that a relative angle between the retroreflective component and the display panel built into the housing can be set arbitrarily.

8. The spatial suspended image display system according to claim 7, wherein: The housing is connected to a power supply unit by a connection portion, and driving power for the display panel and the light source device is supplied from the power supply unit.

9. The spatial suspended image display system according to claim 7, wherein: One end of the frame structure is connected to the shell by a connecting portion. The other end of the housing is connected to the power supply unit via a connecting portion.

10. The spatial suspended image display system according to claim 7, wherein: The imaging position of the spatial floating image can be changed by setting the frame structure to an arbitrary angle relative to the shell using the shell as a setting surface.

11. The spatial suspended image display system according to claim 7, wherein: An image light control sheet for controlling the diffusion characteristics of image light is provided on the image display surface of the display panel. The image light control sheet is arranged between the retro-reflective component and the display panel. The image light control sheet is a viewing angle control film of the display panel.

12. The spatial suspended image display system according to claim 1, wherein: The diffusion angle and diffusion direction of the image light beam diffused from the spatially suspended image can be adjusted by the diffusion characteristics of the image light control sheet and the light source device.

13. The spatial suspended image display system according to claim 7, wherein: The light source device comprises: Point or surface light source; a reflector that reflects light from the light source; and a light guide that guides the light from the reflector toward the display panel, Wherein, the reflective surface of the reflector is in an asymmetric shape with respect to the optical axis of the outgoing light of the light source.

14. The spatial suspended image display system according to claim 13, wherein: The light guide is a reflective light guide.

15. The spatial suspended image display system according to claim 13, wherein: The reflector uses a plastic material, a glass material or a metal material.

16. A spatial suspended image display system, characterized in that: A display panel for displaying an image and a light source device for the display panel are housed in a housing. The invention has a structure in which a transmissive retro-reflective component is held by a frame structure, wherein the transmissive retro-reflective component reflects image light from the display panel and uses the reflected light to display a spatial floating image of a real image in the air. The frame structure is connected to the shell by a connecting portion. The structure is such that the relative angle between the transmissive retroreflective component and the display panel built into the housing can be set arbitrarily. And has a housing structure capable of realizing the following configurations: The housing and the power supply unit are connected by a connection unit, and when the spatial floating image is displayed, the power supply unit is arranged substantially perpendicular to the housing to shield external light incident on the transmissive retroreflective member.

17. A spatial suspended image display system, characterized in that: A display panel for displaying an image and a light source device for the display panel are housed in a housing. A structure in which a retro-reflective component is held by a frame structure, wherein the retro-reflective component reflects image light from the display panel and uses the reflected light to display a spatial floating image of a real image in the air, The frame structure is connected to the shell by a connecting portion. The structure is such that the relative angle between the retro-reflective component and the display panel built into the housing can be set arbitrarily. The housing and the power supply unit are connected by a hinge, and the power supply unit and the housing are attached to the frame structure and folded, thereby forming a portable structure.

18. A spatial suspended image display system, characterized in that: include: Transparent parts; a housing that accommodates the display panel and the light source device and is movably connected to the transparent member via a second connecting portion; a retro-reflective component that reflects light emitted by the display panel housed in the housing toward the transparent component; and A power supply unit, comprising a power supply, Wherein, the retro-reflective component is arranged between the housing and the power supply unit.

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