Space-floating video information display system

Abstract

To display videos with respect to the outside of a space, and to contribute to [3 Wellness and welfare to every persons], [9 Let's build a base of industry and technological innovation] and [11 Construct towns capable of keeping on living] of a sustainable development target according to the present invention.SOLUTION: A spatial floating video information display system comprises: a display panel that displays videos; a light source device for the display panel; a retroreflection member that reflects video light from the display panel, and displays a spatial floating video of an actual image in air by the reflected light; and a transmissivity plate that has a reflection type polarizer converting an optical path of the video light provided in a surface. The transmissivity plate is arranged between the retroreflection member and the display panel. For adjusting a position where the spatial floating video is formed, an attachment angle of an optical member and a position of the display panel are adjusted.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a space floating image information display system and an optical system used therein. [Background technology]

[0002] As a space-floating information display system, an image display device that displays an image directly to the outside and a display method that displays it as a spatial screen are already known. In addition, a detection system that reduces false detections of operations on the operation surface of a displayed spatial image is also disclosed, for example, in Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-128722 Summary of the Invention [Problem to be solved by the invention]

[0004] As a space floating information display system, a video display device that displays an image directly to the outside and a display method that displays an image as a spatial screen are already known. However, in the above-mentioned conventional floating image information display system, no consideration is given to means for preventing malfunctions that occur when external light is incident on the retroreflective member that generates the floating image in space, or to design optimization technology including a light source for the image display device that serves as the image source for the floating image in space, as a floating image information display system, a spatial image information display unit that can set the display position of the floating image in space according to customer requests, and a detection system that operates the displayed image in space.

[0005] The object of the present invention is to provide a space-floating information display system or space-floating image display device that has a unit structure that allows for high visibility (apparent resolution and contrast), displays space-floating images with reduced influence of external light, and allows the display position of the space-floating image to be changed according to customer requests, and to provide a method for highly accurately manipulating the displayed image and a technology that can display suitable images. [Means for solving the problem]

[0006] In order to solve the above problems, for example, the configurations described in the claims are adopted. The present application includes a plurality of means for solving the above problems, and the following is an example of a space-floating image display device. The space-floating image information display system as an example of the present application is as follows: a polarizing beam splitter disposed between the display panel and the retroreflective member that transmits the image light of the specific polarization and reflects the image light converted to the other polarization after being reflected by the retroreflective member; and a second transmissive plate disposed at an opening of a housing of the space-floating image information display system and provided with a polarizing plate sheet. The image light converted to the other polarization after being reflected by the retroreflective member is reflected in a direction substantially perpendicular to the optical axis connecting the display panel and the retroreflective member disposed opposite the display panel, and the reflected image light passes through the second transmissive plate provided with the polarizing plate sheet to display a real image floating in space. [Effects of the Invention]

[0007] According to the present invention, even if external light is incident, the quality of the floating image in space does not deteriorate, and the floating image information in space is displayed appropriately. In addition, the display position of the floating image in space can be set arbitrarily. Furthermore, the floating image display device in space allows operation input without directly touching the display screen. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a principle diagram for explaining the principle and problems of forming a space-floating image in the space-floating image information display system of the present invention; [Figure 2] 1A and 1B are diagrams showing the appearance and main part configuration of an embodiment of a space-floating image information display unit according to an embodiment of the present invention, and the position where a space-floating image is generated. [Figure 3] 1 is an explanatory diagram illustrating the appearance of a space floating image information system according to an embodiment of the present invention, the position where a space floating image is generated, and the horizontal and vertical viewing ranges. [Figure 4] 10 is a diagram showing the appearance and main components of a second embodiment of another space floating image information display system according to an embodiment of the present invention; FIG. [Figure 5]1 is an explanatory diagram for explaining a sensing means provided in a space floating image information display system according to an embodiment of the present invention; [Figure 6] FIG. 10 is a diagram showing another example of a specific configuration of the light source device according to the embodiment of the present invention. [Figure 7A] FIG. 10 is a structural diagram showing another example of a specific configuration of a light source device of another type. [Figure 7B] FIG. 10 is a diagram illustrating a portion of another example of a specific configuration of a light source device of another type. [Figure 7C] FIG. 10 is a diagram illustrating a portion of another example of a specific configuration of a light source device of another type. [Figure 7D] FIG. 10 is a diagram illustrating a portion of another example of a specific configuration of a light source device of another type. [Figure 8A] FIG. 10 is a structural diagram showing another example of a specific configuration of a light source device of another type. [Figure 8B] FIG. 10 is a diagram showing another example of a specific configuration of a light source device of another type. [Figure 9] 10 is an enlarged view showing the surface shape of a light guide diffusion portion of another example of a specific configuration of a light source device. FIG. [Figure 10] FIG. 2 is a cross-sectional view showing an example of a specific configuration of a light source device. [Figure 11] 3A and 3B are structural diagrams showing examples of specific configurations of the light source device. [Figure 12] 1A to 1C are a perspective view, a top view, and a cross-sectional view showing an example of a specific configuration of a light source device. [Figure 13] 1A and 1B are perspective and top views showing an example of a specific configuration of a light source device. [Figure 14] 10A and 10B are explanatory diagrams for explaining the light source diffusion characteristics of the image display device. [Figure 15] 10A and 10B are explanatory diagrams for explaining the light source diffusion characteristics of the image display device. [Figure 16] FIG. 10 is an explanatory diagram for explaining the diffusion characteristics of a video display device. [Figure 17] FIG. 10 is an explanatory diagram for explaining the diffusion characteristics of a video display device. [Figure 18] FIG. 1 is a diagram showing a coordinate system for measuring visual characteristics of a liquid crystal panel. [Figure 19] FIG. 1 is a diagram showing the luminance angle characteristics (longitudinal direction) of a typical liquid crystal panel. [Figure 20] FIG. 1 is a diagram showing the luminance angle characteristics (short side direction) of a typical liquid crystal panel. [Figure 21] FIG. 1 is a diagram showing the angle characteristics (longitudinal direction) of contrast of a typical liquid crystal panel. [Figure 22] FIG. 1 is a diagram showing the angle characteristics (short side direction) of contrast of a typical liquid crystal panel. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the contents of the embodiments described below (hereinafter also referred to as "the present disclosure"). The present invention also extends to the spirit of the invention and the scope of the technical ideas described in the claims, or equivalents thereof. Furthermore, the configurations of the embodiments (examples) described below are merely examples, and various changes and modifications are possible by those skilled in the art within the scope of the technical ideas disclosed in this specification.

[0010] Furthermore, in the drawings for explaining the present invention, components having the same or similar functions are given the same reference numerals, and different names are used as appropriate, while repeated explanations of functions, etc. may be omitted. In the following description of the embodiments, an image floating in space is expressed using the term "space-floating image." Instead of this term, it is also acceptable to express it as "aerial image," "spatial image," "floating image," "space-floating optical image of displayed image," "floating optical image of displayed image," etc. The term "space-floating image," which is mainly used in the description of the embodiments, is used as a representative example of these terms.

[0011] The present disclosure relates to an information display system that can display an image generated by image light from a large-area image light source as a floating image inside or outside a store (space) by transmitting the image through a transparent member that divides the space, such as the glass of a shop window. The present disclosure also relates to a large-scale digital signage system configured using multiple such information display systems.

[0012] According to the following embodiment, for example, high-resolution video information can be displayed in a floating state on the glass surface of a shop window or a light-transmitting plate. In this case, by making the divergence angle of the emitted video light small, i.e., acute, and further aligning it with a specific polarization, it is possible to efficiently reflect only the normal reflected light from the retroreflective member. This results in high light utilization efficiency, and it is possible to suppress the ghost images that occur in addition to the main floating image in space and the colored reflected light caused by external light incident on the retroreflective member, which were issues with conventional retroreflective methods, thereby obtaining a clear floating image in space.

[0013] Furthermore, a device including the light source of the present disclosure can provide a novel and highly usable floating image information display system that can significantly reduce power consumption. Furthermore, the technology of the present disclosure can provide a floating image information display system for a vehicle that can display a so-called unidirectional floating image that can be viewed from outside the vehicle through shield glass such as the vehicle's windshield, rear window, or side window.

[0014] On the other hand, conventional floating-image information display systems combine an organic electroluminescence (EL) panel or liquid crystal display panel (LCD panel or display panel) as a high-resolution color display image source with a retroreflective member. The first retroreflective member 2 used in conventional floating-image display devices diffuses image light over a wide angle. Therefore, in addition to the light reflected normally by the first embodiment of the retroreflective member, which is composed of a polyhedron as shown in FIG. 1(B), the shape used for the retroreflective portion 2a is hexahedral, as shown in FIG. 1(B), and the image light incident from an oblique angle generates multiple ghost images, impairing the image quality of the floating image. Furthermore, the ghost images of the same floating image can be seen by people other than the viewer, posing a major security issue.

[0015] Next, the function of the retroreflective member used in the space-floating image display device and a specific example of the space-floating image display device will be described. As shown in Figure 1(A), a reflective polarizer 101 that reflects light of a specific polarization and is provided on a second transmissive plate 100 arranged at an angle of approximately 45 degrees relative to the image display device 1 is used to reflect the light, and a space-floating image is obtained by a retroreflective member 2 that is arranged at an angle of approximately 45 degrees relative to the second transmissive plate 100 or the reflective polarizer 101. A λ / 4 plate 21 is provided on the surface of the retroreflective member 2, and the image light is converted to the other polarization by a retardation plate before being incident on and reflected from the retroreflective member 2, and then passes through the reflective polarizer 101 and the absorbing polarizer 102 provided on the second transmissive plate 100 to obtain a space-floating image in the space separated by the second transmissive plate 100.

[0016] As shown in FIG. 1(B), the retroreflective member 2 has a structure in which the reflective surfaces of polyhedrons are aligned, and the image light is reflected twice by the polyhedrons 2a (hexahedrons in the figure), becoming retroreflected light and forming a floating image in the air. The resolution of the floating image is generally determined by the pitch per unit area of ​​the polyhedrons 2a on the retroreflective member 2. The aerial image 220 formed by the image light reflected by the retroreflective member 2 is formed in the space separated by the second transmissive plate 100, and the distance from the retroreflective member 2 to the aerial image 220 is the same as the optical distance from the image display device 1 to the retroreflective member 2. If the diffusion angle of the image light is large, abnormal light other than the image light normally reflected by the polyhedrons on the reflective surface of the retroreflective member 2 is generated, resulting in ghost images g1 and g2 (which occur depending on the number of reflective surfaces, but only two are shown in FIG. 1) around the normal aerial image 220. In order to reduce this ghost image, it is advisable to set the diffusion angle of the light source 13 provided in the image display device 1 to a narrow diffusion angle as will be described later.

[0017] <Configuration Example of the First Retroreflection Optical System or Retroreflection Optical Unit Forming the Space Floating Image Information Display System> Fig. 2(A) is a diagram showing an example of the configuration of a retro-optical system (hereinafter also referred to as a "unit") used to realize the space-floating image information display system of the present disclosure. Fig. 2(B) is a diagram explaining the overall configuration of the space-floating image information display system of this embodiment. A space-floating image display system or a space-floating image display device having a light source device 13, a display panel 11, a retro-reflective member 2, and a first transmissive plate 110 is incorporated into a housing, and a member for connecting to the space-floating image display system or the space-floating image display device is provided in a part of the housing.

[0018] Referring to FIG. 2(A), for example, according to the spatially floating information display system (hereinafter also referred to as "the present system") of the present disclosure, when the spatially floating image information display system is placed on a desk, a viewer of the spatially floating image will view the spatially floating image from above. In FIG. 2(A), the image display device 1 and the retroreflective member 2 are arranged substantially parallel or parallel to each other. Specifically, the image display surface or image light exit surface of the display panel 11 constituting the image display device 1 is arranged directly opposite the reflective surface of the retroreflective member 2. At this time, the imaging position of the spatially floating image (shown at 220A and 220B in FIG. 2(A)) moves up and down according to the amount of movement of the image display device 1 along the second transmissive plate 100 in the left-right direction in the figure. Here, the left-right movement of the image display device 1 refers to movement toward and away from the retroreflective member 2, as shown in FIG. 2(A). That is, even in the same system, by changing the position of the image display device 1, the imaging position of the space floating image can be changed arbitrarily.

[0019] The function of the optical members that make up the retroreflective optical system described above will be described below. The image display device 1 is composed of a light source device 13 with narrow-angle diffusion characteristics and a liquid crystal display panel 11. As a result, in the spatial information display system of the present invention, image light of a specific polarization with narrow-angle diffusion characteristics is obtained and directed toward the first transmissive plate 110. One side of the first transmissive plate 110 is provided with a reflective polarizing plate sheet 111 that functions as a polarizing beam splitter, but the specific polarized light from the image display device 1 is transmitted through it. In this case, the light incident surface of the first transmissive plate 110 may be provided with an anti-reflection film or a sheet 113 with a moth-eye structure on its surface, whose reflectance does not change with the angle of incidence or wavelength of the light ray.

[0020] The image light transmitted through the first transmissive plate 110 is retroreflected by the retroreflective member 2. The first transmissive plate 110 is arranged at an angle θ1 (approximately 45 degrees) with respect to the optical axis connecting the image display device 1 and the retroreflective member 2. If this tilt angle θ1 is made larger than 45 degrees, the imaging position of the floating image 220A shown in FIG. 2(A) can be moved to the left side of the drawing. Similarly, the imaging position of the floating image 220A shown in FIG. 2(A) can be moved to the right side of the drawing. As described above, with the unit configuration of the present invention, the imaging position of the floating image in space can be adjusted to a desired position by changing the arrangement of the optical members that make up the unit, so the basic configuration of the unit can be standardized and mass production efficiency can be improved.

[0021] The retroreflective member 2 not only forms retroreflected light, but also converts the image light of the specific polarization into the other polarization using a λ / 4 plate provided on the surface, so that the light is reflected by the reflective polarizer sheet 111 provided on one side of the first transmissive plate 110 and passes through the first transmissive plate 110 provided on the upper surface, forming a spatially floating image 220A. An anti-reflection film or a sheet 104 having a moth-eye structure on its surface, whose reflectance does not change depending on the angle of incidence or wavelength of light, may be provided on the air-side interface of the λ / 4 plate 21 provided on the surface of the retroreflective member 2.

[0022] By moving the installation position of the image display device 1 described above in the left-right direction of the drawing and setting it at any position, the generation position of the space-floating image 220A can be set to, for example, position 220B. As shown in FIG. 2(A), the image display device 1 and the retroreflective member 2 are arranged so that they are approximately parallel to each other. In this case, if you want to increase the floating amount of the space-floating image (the distance from the first transmissive plate 110), you can simply increase the distance from the image display device 1 to the retroreflective member 2, and in the embodiment shown in FIG. 2(A), this can be set by moving the image display device 1 to the right. The floating amount here is the distance from the first transmissive plate 110 to the space-floating image.

[0023] The space-floating image display system or space-floating image display device of this embodiment may have a structure for moving the image display device 1 or the display panel 11, specifically, the image display device 1 is fixed to the housing via an elastic member. Also, the space-floating image display system or space-floating image display device may have a structure for adjusting the arrangement angle of the first transmissive plate 110, specifically, the first transmissive plate 110 is fixed to the housing via an elastic member.

[0024] Therefore, the imaging position of the space-floating image changes depending on the distance between the image display device 1 (or the display panel 11) and the first transmissive plate 110. In other words, when the arrangement angle of the first transmissive plate 110 is constant, the imaging position of the space-floating image is a position determined depending on the distance between the image display device 1 or the display panel 11 and the first transmissive plate 110. Alternatively, the imaging position of the space-floating image changes depending on the arrangement angle of the first transmissive plate 110. In other words, when the distance between the image display device 1 and the first transmissive plate 110 is constant, the imaging position of the space-floating image is a position determined depending on the arrangement angle of the first transmissive plate 110.

[0025] In this unit, the distance connecting any point on the image display device 1 or the display panel 11 and the corresponding point on the first transmissive plate 110 and the distance connecting any point on the space-floating image 220A and the corresponding point on the first transmissive plate 110 are equal at all positions in the left and right direction of the space-floating image 220A, so the sense of focus of the formed space image can be equally good across the entire screen area, and a space-floating image can be obtained. Specifically, the distance connecting any point on the image light exit surface of the display panel 11 and the corresponding point on the first transmissive plate 110 and the distance connecting any point on the space-floating image 220A and the corresponding point on the first transmissive plate 110 are equal at all positions in the left and right direction of the space-floating image 220A.

[0026] Furthermore, external light that enters the unit from outside the housing through the second transmissive plate 100, which is an opening, is approximately perpendicular to the first transmissive plate 110 and does not directly enter the retroreflective member 2, which is located at a position away from the opening, or the surface of the image display device 1. Furthermore, of the external light that enters the housing, light of the same polarized wave as the image light of a specific polarized wave from the image display device 1 passes through the reflective polarizer sheet 111, which acts as a polarized beam splitter provided on one side of the first transmissive plate 110, and is absorbed by the light absorber 106, and does not affect the image quality of the spatially floating image.

[0027] Furthermore, in order to allow the viewer to interact with this floating image by touching it and use it as a key input device, for example, good performance can be obtained by placing the sensing system 203 (described later) at the edge of the floating image in space and making the detection area larger than the floating image in space.

[0028] <Configuration example of a space floating video information display system> 2(B) is a diagram showing the configuration of the space-floating image information display system of the present disclosure. The functions of the optical members that make up the unit shown in FIG. 2(A) have been described above, so they will not be explained here. The space-floating image display system or space-floating image display device, which has a light source device 13, a display panel 11, a retroreflective member 2, and a first transmissive plate 110, is incorporated into a housing, and a member that connects to the space-floating image display system or space-floating image display device is provided in part of the housing.

[0029] Specifically, by fixing this unit to the main body 107 and the rotating structure 108 that support it, referring to the space-floating image 204 (the image formation position is shown in A1 and A2), for example, according to the system of the present disclosure, when this system is placed facing the viewer of the space-floating image, the viewer will view the space-floating image diagonally downward. At this time, in order to optimally position the image formation position of the space-floating image 204 in the front-to-back direction relative to this system, if the position of the image display device 1 of the unit shown in the same figure is moved in the up-down direction in the figure, it will move forward and backward (left-to-right direction in the figure) according to this movement amount. In other words, even with the same type of system, by changing the position of the image display device 1, the image formation position of the space-floating image can be optimized as desired according to the customer's request.

[0030] 2(A), the retroreflective member 2 not only forms retroreflected light, but also converts the image light of the specific polarization into the other polarization using a λ / 4 plate provided on the surface, which causes the light to be reflected by a reflective polarizer sheet 111 provided on one side of the first transmissive plate 110 and pass through a second transmissive plate 100 provided on the upper surface, forming a spatially floating image 220A. An anti-reflection film or a sheet 113 having a moth-eye structure on its surface, whose reflectance does not change depending on the angle of incidence or wavelength of light, may be provided on the air-side interface of the λ / 4 plate 21 provided on the surface of the retroreflective member 2.

[0031] By moving and setting the installation position of the image display device 1 described above in the vertical direction of the drawing, the generation position of the floating-in-space image 204 can be arbitrarily set, for example, in the forward or backward direction toward the viewer. In this case, if it is desired to increase the floating amount of the floating-in-space image (distance from the second transmissive plate 100), it is sufficient to increase the distance from the image display device 1 to the retroreflective member 2, and in the embodiment shown in Figure 2(B), it is preferable to move the image display device 1 upward. As shown in Figure 2(B), moving the installation position of the image display device 1 in the vertical direction here means moving the image display device 1 in the vertical direction along the second transmissive plate 100, or moving the image display device 1 in the vertical direction relative to the second transmissive plate 100.

[0032] In this unit as well, the distance connecting the center point of the image display device 1 or the display panel 11 and the corresponding point on the first transmissive plate 110 and the distance connecting the center point of the space-floating image 204 and the corresponding point on the first transmissive plate 110 are equal at all positions in the up and down direction of the space-floating image, so that the sense of focus of the formed space image is equal across the entire screen area, resulting in a space-floating image with good focus. The center point of the image display device 1 or the display panel 11 here is the center point of the image light exit surface of the image display device 1 or the display panel 11.

[0033] Furthermore, external light that enters the unit from outside the housing through the second transmissive plate 100, which is the opening, is approximately perpendicular to the second transmissive plate 100 and does not directly enter the surface of the retroreflective member 2 or the image display device 1, which are located away from the opening, and therefore does not affect the image quality of the floating image.

[0034] Furthermore, by allowing the viewer to touch this floating image in space, interaction can be achieved, for example, to use it as a key input device, by placing the sensing system 203 described later inside the housing, a sensing system that is less affected by the usage environment can be realized. At this time, the near-infrared light used for sensing passes through the first transparent plate 110, so it does not affect the sensing performance. Furthermore, by making the detection area of ​​this sensing system larger than the floating image in space 204, good performance can be obtained.

[0035] <Example of a floating video information display system> FIG. 3(A) shows the exterior of the space-floating image information display system of the present disclosure. The system incorporates the unit shown in FIG. 2(B), and is fixed to a main body 107 and a rotating structure 108 (not shown) that support the unit, generating a space-floating image A1 at a desired position. The position of the space-floating image can be changed by adjusting the set angle θ3 of the unit installed inside the system. For example, if the reference set position is A1, the angle θ3 of the entire unit can be increased to position the space-floating image at the upper position A2. Alternatively, the mounting angle θ4 of the retroreflective member 2 can be set to an angle that is open relative to the image display device 1. Furthermore, a similar effect can be achieved by tilting the set angle θ5 of the second transmissive plate 100 equipped with the reflective polarizer sheet 101 more significantly relative to the opening of the housing. In this case, the detection area 205 of the sensing system described above should be determined to encompass all of the space-floating images, the positions of which change depending on the arrangement of the optical components that make up the unit.

[0036] <Technology for controlling diffusion characteristics of video display devices> In an embodiment of the present invention, the diffusion distribution of image light from the liquid crystal display panel 11, which is the image source of the image display device 1, is adjusted by adjusting the diffusion characteristics of the light source device 13 and the shape and surface roughness of the light guide surface. Furthermore, a lenticular lens is provided between the retroreflective member 2 and the liquid crystal display panel 11 or on the surface of the liquid crystal display panel 11, and the emission direction of the image light is controlled by optimizing the shape of the lens. In other words, by optimizing the shape of the lenticular lens, it is possible to adjust the emission characteristics of the image light (hereinafter also referred to as "image luminous flux") emitted in one direction from the liquid crystal display panel 11.

[0037] 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 may be adjusted. That is, by adjusting the arrangement of the microlens array, it is possible to adjust the emission characteristics in the X-axis and Y-axis directions of the image light beam emitted from the image display device 1, and as a result, it is possible to obtain an image display device with desired diffusion characteristics.

[0038] As a further configuration example, two lenticular lenses may be combined and arranged at a position where the image light emitted from the image display device 1 passes, or a sheet for adjusting the diffusion characteristics by arranging a microlens array in a matrix may be provided. By configuring the optical system in this way, the brightness (relative brightness) of the image light in the X-axis and Y-axis directions can be adjusted according to the reflection angle of the image light (reflection angle with the vertical reflection as the reference (0 degrees)).

[0039] In this embodiment, by using such a lenticular lens, different diffusion characteristics can be obtained in each plane, as shown in the graphs (plot curves) of "Example 1 (ZY direction)" in Figure 3(B) and "Example 2 (ZX direction)" in Figure 3(C). Specifically, as shown in the graphs of "Example 1 (ZY direction)" in Figure 3(B) and "Example 2 (ZX direction)" in Figure 3(C), the horizontal viewing angle characteristic of the space-floating image information device is set to characteristic O in the ZX plane, while the vertical diffusion characteristic is set to characteristic A shown in Figure 3(B), making it possible to individually control the diffusion characteristics. As a result, the optimal viewing angle characteristic can be obtained depending on the application of the space-floating image display device, and a space-floating image with higher brightness can be obtained compared to image display devices using conventional light source devices with diffusion characteristics.

[0040] <Second example of the configuration of the space floating image information display system> A second embodiment of the space-floating image information display system will be described with reference to Fig. 4. Fig. 4 shows the unit shown in Fig. 2(B) arranged inside the housing 121, with a sensing unit (not shown) provided inside the first transmissive plate 110 to ensure a sensing area 205 of sufficient size for the space-floating image A1. The sensing unit 203 shown in Fig. 5 is arranged inside the housing 121, and an O-ring or the like is provided on the housing side of the first transmissive plate 110 to prevent external moisture from entering. The sensing unit 203, which senses the sensing area (sensing region) 205 that covers the imaging area A1 of the space-floating image display device, is arranged inside the housing 121 and forms the sensing area by passing through the first transmissive plate 110.

[0041] In the second embodiment of the image information display system described above, the user can also perform spatial operation inputs to the displayed floating image A1. Furthermore, as a result of evaluating finger contact with a prototype using an actual device, it was found that by separating the imaging position of the floating image A1 from the first transparent plate 110 by 50 mm or more, the operator could perform spatial operation inputs to the image information display system without touching the screen.

[0042] As described above, the configuration described in FIG. 4 may be incorporated into various display devices such as ATMs, automatic ticket vending machines, kiosk terminals, and stationary display devices.

[0043] <Technical means for sensing spatial images> In order to allow the viewer (operator) to be connected to the information system bidirectionally via the space-floating image display device, sensing technology for pseudo-operating the space-floating image will be described below.

[0044] In the space-floating image information system, sensing information is read together with the space-floating image using a two-dimensional sensor (described later), enabling image manipulation of the displayed image.

[0045] The sensing technology used to virtually manipulate floating images in space, so that viewers (operators) can be connected to an information system two-way via a floating image display device, is described below. Figure 5 is a diagram illustrating the principle of the sensing technology. A distance measuring device 203 with a built-in TOF (Time of Flight) system compatible with floating images in space is installed. A near-infrared LED (Light Emitting Diode), which serves as the light source, emits light in synchronization with the system's signal. An optical element is installed on the light-emitting side of the LED to adjust the divergence angle, and a pair of highly sensitive avalanche diodes with picosecond time resolution are used as light-receiving elements, aligned horizontally to correspond to the area.

[0046] The LED light source emits light in synchronization with a signal from the system, and the phase Δt is shifted by the time it takes for the light to reflect off the object to be measured (the tip of the viewer's finger) and return to the light receiving unit. The distance to the object is calculated from this time difference Δt, and the position and movement of the operator's finger are sensed as 2D information in combination with the position information of multiple sensors arranged in parallel. As a result, a space-floating information display system or space-floating image display device can be realized with sensing functions that have few false detections for space-floating images.

[0047] <Ghost image reduction technology> When a 7-inch WUXGA (1920 x 1200 pixels) liquid crystal display panel is used as the liquid crystal panel 11 used in the image display device 1, even if one pixel (one triplet) is approximately 80 μm, if the pitch B is 420 μm, for example, consisting of a 400 μm transmissive portion d2 of the retroreflective part and a 20 μm light-absorbing portion d1, sufficient transmission characteristics are achieved, and the diffusion characteristics of the image light from the image display device, which is the cause of abnormal light in the retroreflective member, are controlled to reduce ghost images that appear on both sides of the spatially floating image.

[0048] An image light control sheet is provided on the surface of the liquid crystal panel 11. This image light control sheet prevents external light from the outside from penetrating into the spatial floating image display device and entering the liquid crystal panel 11, which also leads to improved reliability of the components. For example, a viewing angle control film (VCF) from Shin-Etsu Polymer Co., Ltd. is suitable as this image light control sheet, and its structure is a sandwich structure in which transparent silicon and black silicon are alternately arranged with synthetic resin placed on the light entrance and exit surfaces, making it possible to control external light.

[0049] <LCD panel performance> Incidentally, in a typical TFT (Thin Film Transistor) liquid crystal panel, the brightness and contrast performance differ depending on the light output direction due to the mutual characteristics of the liquid crystal and polarizer. In an evaluation in the measurement environment shown in Figure 18, the brightness and viewing angle characteristics in the short side (up and down) direction of the panel were superior at an angle slightly shifted (+5 degrees in this example) from the output angle perpendicular to the panel surface (output angle of 0 degrees), as shown in Figure 20. The reason for this is that in the short side (up and down) direction of the liquid crystal panel, the light twisting characteristic does not become 0 degrees when the applied voltage is at its maximum.

[0050] On the other hand, as shown in Figure 22, 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, and when combined with the brightness characteristics, the best characteristics are obtained when used in the range of ±10 degrees with 5 degrees as the center.

[0051] Furthermore, the brightness and viewing angle characteristics in the longitudinal (left-right) direction of the panel are superior at an output angle perpendicular to the panel surface (output angle of 0 degrees), as shown in Figure 19. The reason for this is that the light twisting characteristic in the longitudinal (left-right) direction of the liquid crystal panel becomes 0 degrees when the applied voltage is at its maximum.

[0052] Similarly, the contrast performance in the longitudinal (left-right) direction of the panel is excellent in the range of -5 degrees to -10 degrees, and when combined with the brightness characteristics, the best characteristics are obtained when used in the range of ±5 degrees with -5 degrees as the center. For this reason, the image quality and performance of the image display device 1 are improved by making the light emitted from the liquid crystal panel incident on the liquid crystal panel from a direction that provides the best characteristics using the light beam direction conversion means (reflecting surfaces 307, 314, etc.) provided on the light guide of the light source device 13 described above, and modulating the light with a video signal.

[0053] In order to make the most of the brightness and contrast characteristics of the liquid crystal panel as an image display element, the image quality of the floating image can be improved by setting the incident light from the light source to the liquid crystal panel within the above-mentioned range.

[0054] <Light source light control method> In this embodiment, as shown in Figure 6, in order to improve the utilization efficiency of the light beam emitted from the light source device 13 and significantly reduce power consumption, in an image display device 1 comprising a light source device 13 and a liquid crystal display panel 11, light from the light source device 13 is incident on the liquid crystal panel 11 at an incident angle that maximizes the characteristics of the liquid crystal panel 11, and then image light that has been brightness-modulated in accordance with the image signal is emitted toward the retroreflective member. At this time, in order to reduce the set volume of the spatial floating image information display system, it is desired to increase the degree of freedom in the arrangement of the liquid crystal panel 11 and the retroreflective member. Furthermore, in order to form the floating image at a desired position after retroreflection and ensure optimal directionality, the following technical means are used.

[0055] A transparent sheet made of optical components such as a linear Fresnel lens shown in front of the light direction conversion panel is provided on the image display surface of the liquid crystal panel 11, and the image position of the floating image in space is determined by controlling the output direction of the incident light beam to the retroreflective optical element while providing high directivity. With this configuration, the image light from the image display device 1 reaches the observer efficiently with high directivity (straightness) like laser light, resulting in the display of high-quality floating images with high resolution and a significant reduction in power consumption by the image display device 1 including the light source device 13.

[0056] <Example 1 of video display device> Fig. 11 shows another example of the specific configuration of the image display device 1. The light source device in Fig. 11 is similar to the light source device in Fig. 12 etc. This light source device 13 is configured by housing LEDs, a collimator, a composite diffusion block, a light guide, etc. in a case made of, for example, plastic, and has a liquid crystal display panel 11 attached to its upper surface. Also, an LED board on which LED (Light Emitting Diode) elements 14a and 14b, which are semiconductor light sources, and their control circuits are mounted are attached to one side of the case of light source device 13, and a heat sink (not shown), which is a member for cooling heat generated by the LED elements and the control circuit, is attached to the outer surface of the LED board.

[0057] The liquid crystal display panel frame attached to the top surface of the case is configured to have attached thereto a liquid crystal display panel 11 attached to the frame, and further to have attached thereto an FPC (Flexible Printed Circuits) (not shown) electrically connected to the liquid crystal display panel 11. That is, the liquid crystal display panel 11, which is a liquid crystal display element, generates a display image by modulating the intensity of transmitted light together with the LED elements 14a and 14b, which are solid-state light sources, based on a control signal from a control circuit (not shown here) that constitutes the electronic device.

[0058] <Example 1 of Light Source Device for Example 1 of Image Display Device> Next, the configuration of the optical system, such as the light source device housed in the case, will be described in detail with reference to Fig. 10 as well as Figs. 12(a) and (b). Figs. 10 and 11 show LEDs 14a and 14b constituting the light source, which are attached at predetermined positions relative to a collimator 15. Each collimator 15 is formed of a light-transmitting resin such as acrylic. As shown in Fig. 11(b), the collimator 15 has a conical convex outer circumferential surface 156 obtained by rotating a parabolic cross section, and a recess 153 with a convex portion (i.e., a convex lens surface) 157 formed in the center of its apex (the side in contact with the LED substrate).

[0059] Furthermore, the central part of the flat part (the side opposite to the apex) of the collimator 15 has a convex lens surface 154 that protrudes outward (or may be a concave lens surface that is recessed inward). The parabolic surface 156 that forms the outer peripheral surface of the cone shape of the collimator 15 is set within an angle range that allows the light emitted from the LEDs 14a and 14b in the peripheral direction to be totally reflected therein, or a reflective surface is formed thereon.

[0060] The LEDs 14a and 14b are arranged at predetermined positions on the surface of the circuit board, 102. The substrate 102 is arranged and fixed to the collimator 15 so that the LEDs 14a and 14b on the surface are located at the center of the recess 153.

[0061] According to this configuration, the collimator 15 described above condenses the light emitted from the LED 14a or 14b, particularly the light emitted upward from the central portion (toward the right in the figure), into parallel light by the two convex lens surfaces 157, 154 that form the outer shape of the collimator 15. Furthermore, the light emitted from other portions toward the periphery is reflected by the parabolic surface that forms the outer peripheral surface of the conical shape of the collimator 15, and is similarly condensed into parallel light. In other words, the collimator 15, which has a convex lens in its center and a parabolic surface formed on its periphery, makes it possible to extract almost all of the light generated by the LED 14a or 14b as parallel light, thereby improving the utilization efficiency of the generated light.

[0062] A polarization conversion element 21 is provided on the light exit side of the collimator 15. The polarization conversion element 21 may also be referred to as a polarization conversion member. As is clear from FIG. 11(a), this polarization conversion element 21 is configured by combining a columnar light-transmitting member having a parallelogram cross section (hereinafter referred to as a parallelogram prism) and a columnar light-transmitting member having a triangular cross section (hereinafter referred to as a triangular prism), and arranging a plurality of these in an array parallel to a plane perpendicular to the optical axis of the collimated light from the collimator 15. Furthermore, a polarization beam splitter (hereinafter referred to as a "PBS film") 211 and a reflective film 212 are alternately provided at the interface between adjacent light-transmitting members arranged in the array, and a λ / 2 plate 213 is provided on the exit surface from which light incident on the polarization conversion element 21 and transmitted through the PBS film 211 exits.

[0063] 11(a) is further provided on the exit surface of this polarization conversion element 21. That is, the light emitted from LED 14a or 14b is converted into parallel light by the action of collimator 15, enters synthesizing / diffusing block 16, is diffused by texture 161 on the exit side, and then reaches light guide 17.

[0064] The light guide 17 is a rod-shaped member made of a translucent resin such as acrylic and having an approximately triangular cross section (see Figure 11(b)). As can be seen from Figure 25, the light guide 17 has a light incident portion (surface) 171 that faces the exit surface of the synthetic diffusion block 16 via a first diffuser plate 18a, a light guide light reflecting portion (surface) 172 that forms an inclined surface, and a light guide light exit portion (surface) 173 that faces the liquid crystal display panel 11, which is a liquid crystal display element, via a second diffuser plate 18b.

[0065] 10, which is a partially enlarged view, a number of reflective surfaces 172a and connecting surfaces 172b are alternately formed in a sawtooth pattern on the light guide light reflecting portion (surface) 172 of the light guide 17. The reflective surfaces 172a (line segments sloping upward to the right in the figure) form angles αn (n: natural number, for example, 1 to 130 in this example) with respect to the horizontal plane indicated by the dashed dotted line in the figure, and as an example, αn is set to 43 degrees or less (but 0 degree or more).

[0066] Light guide entrance portion (surface) 171 is formed in a curved convex shape inclined toward the light source. Accordingly, the parallel light from the exit surface of synthetic diffusion block 16 is diffused and incident via first diffuser plate 18a, and as is clear from Fig. 10, the parallel light is bent (deflected) slightly upward by light guide entrance portion (surface) 171 before reaching light guide light reflecting portion (surface) 172, where it is reflected and reaches liquid crystal display panel 11 provided on the exit surface at the top of the figure.

[0067] According to the image display device 1 described above in detail, it is possible to further improve the light utilization efficiency and its uniform illumination characteristics, and at the same time, it is possible to manufacture a compact and low-cost device, including a modularized S-polarized light source device. In the above explanation, the polarization conversion element 21 is described as being attached after the collimator 15, but the present invention is not limited to this, and similar functions and effects can be obtained by providing it in the optical path leading to the liquid crystal display panel 11.

[0068] The light guide light reflecting portion (surface) 172 has a number of alternating reflective surfaces 172a and connecting surfaces 172b formed in a sawtooth pattern. The illumination light beam is totally reflected by each reflective surface 172a and directed upward. The light beam then enters the light redirecting panel 54, which adjusts the directional characteristics of the light beam by providing a narrow-angle diffuser plate on the light guide light exiting portion (surface) 173. The light exiting direction of the image display device 1 is adjusted by the light redirecting panel 54 provided on the upper surface of the light source device 13. As a result, the light exiting from the liquid crystal display panel 11 is also controlled, thereby controlling the light diffusion direction of the spatially floating image produced by the spatially floating image information system using the image display device 1. In this embodiment, the light redirecting panel 54 is provided between the light guide exiting surface 173 and the liquid crystal display panel 11. However, the same effect can be achieved by providing the light redirecting panel 54 on the exiting surface of the liquid crystal display panel 11.

[0069] In a typical TV device, the light emitted from the liquid crystal display panel 11 has similar diffusion characteristics in the horizontal direction of the screen (the display direction corresponding to the X-axis of the graph in FIG. 30(A)) and the vertical direction of the screen (the display direction corresponding to the Y-axis of the graph in FIG. 17(B)), as shown in the plot curves of "conventional characteristics (X direction)" in FIG. 17(A) and "conventional characteristics (Y direction)" in FIG. 17(B).

[0070] In contrast, the diffusion characteristics of the light beam emitted from the liquid crystal display panel of this embodiment are, for example, as shown in the plot curves of "Example 1 (X direction)" in FIG. 17(A) and "Example 1 (Y direction)" in FIG. 17(B).

[0071] In one specific example, when the viewing angle at which the brightness is 50% (brightness reduced to about half) of the brightness when viewed from the front (angle of 0 degrees) is set to 13 degrees, this angle is about 1 / 5 of the diffusion characteristics of a typical home TV (angle of 62 degrees). Similarly, in one example where the vertical viewing angles are set unevenly between the upper and lower sides, the reflection angle of the reflective light guide and the area of ​​the reflective surface are optimized so that the upper viewing angle is held down (narrowed) to about 1 / 3 of the lower viewing angle.

[0072] By setting the viewing angle and other settings as described above, the amount of light in the image directed toward the user's viewing direction increases dramatically (significantly improving image brightness) compared to conventional LCD TVs, and the brightness of the image becomes more than 50 times greater.

[0073] Furthermore, in the case of the viewing angle characteristics shown in "Example 2" in Fig. 17, if the viewing angle at which the brightness of the image obtained when viewed from the front (angle of 0 degrees) is 50% (brightness reduced to about half) is set to 5 degrees, the angle (narrow viewing angle) will be about 1 / 12 of the diffusion characteristics (angle of 62 degrees) of a typical home TV device. Similarly, in an example where the vertical viewing angle is set equally on the top and bottom sides, the reflection angle and the area of ​​the reflective surface of the reflective light guide are optimized so that the vertical viewing angle is reduced (narrowed) to about 1 / 12 of the conventional value.

[0074] By making these settings, the brightness (amount of light) of the image in the viewing direction (the direction of the user's line of sight) is significantly improved compared to conventional LCD TVs, and the brightness of the image is more than 100 times higher.

[0075] As described above, by setting the viewing angle to a narrow angle, the amount of luminous flux directed in the viewing direction can be concentrated, significantly improving light utilization efficiency. As a result, even when using a liquid crystal display panel for general TV applications, by adjusting the light diffusion characteristics of the light source device, it is possible to achieve a significant improvement in brightness with similar power consumption, making it possible to create a video display device that is suitable for information display systems facing bright outdoor environments.

[0076] When using a large LCD panel, the brightness of the screen can be improved by directing the light from the periphery of the screen inward so that it is directed toward the viewer when the viewer is facing the center of the screen. Figure 14 shows the convergence angle between the long and short sides of the LCD panel when the distance L from the LCD panel to the viewer and the panel size of the image display device (screen ratio 16:10) are used as parameters. The upper diagram assumes that the image is viewed with the LCD panel screen in portrait orientation (hereinafter also referred to as "portrait viewing"). In this case, the convergence angle can be set to match the short side of the LCD panel (see the direction of arrow V in Figure 14 as appropriate).

[0077] As a more specific example, as shown in the plot graph in FIG. 14, when a 22-inch panel is used vertically and the viewing distance is 0.8 m, by setting the convergence angle to 10 degrees, the image light from each corner (four corners) of the screen can be effectively projected or output toward the viewer.

[0078] Similarly, when viewing a 15" panel in portrait orientation, a convergence angle of 7 degrees will allow image light from the four corners of the screen to be effectively directed toward the viewer at a viewing distance of 0.8 m. As described above, the overall brightness of the screen can be improved by directing image light from the periphery of the screen toward the viewer who is in the optimum position to view the center of the screen, depending on the size of the LCD panel and whether it is used portrait or landscape.

[0079] As shown in Figure 17 above, the basic configuration involves a light source device directing a light beam with a narrow angle of directionality to the liquid crystal display panel 11, which is then luminance-modulated according to the video signal. The video information displayed on the screen of the liquid crystal display panel 11 is then reflected by the retroreflective member, and the resulting floating image is displayed indoors or outdoors via the transparent member 100.

[0080] A number of other examples of the light source device will be described below, and any of these other examples of the light source device may be used in place of the light source device in the example of the image display device described above.

[0081] As mentioned above, when a large LCD panel is used, the light from the periphery of the screen can be directed inward toward the viewer when the viewer is facing the center of the screen, improving the overall brightness of the screen, but on the other hand, binocular parallax occurs depending on whether the viewer uses their left or right eye to view the image. Figure 15 shows the convergence angle between the long and short sides of the LCD panel, calculated based on the positions of the left and right eyes, when the distance L from the LCD panel to the viewer and the panel size of the image display device (screen ratio 16:10) are used as parameters.

[0082] The smaller the panel size and the closer the viewing distance, the larger the convergence angle in binocular vision by the left and right eyes. When using a small panel of 7 inches or less, the convergence angle due to binocular parallax is an important requirement. For example, when using a panel of 7 inches or less, the light diffusion characteristics of the light source shown in Figure 17 should be expanded or given directional characteristics so that the image light is directed toward the optimal viewing range of the system.

[0083] Furthermore, depending on the required specifications of the system, it may be necessary to optimally design the shape, surface roughness, inclination, etc. of the reflective surface of the light guide of the light source device 13 described above in order to obtain horizontal and vertical directional characteristics and diffusion characteristics.

[0084] <Light source device example 1> Next, another example of the light source device will be described with reference to Fig. 6. Fig. 6(a) and Fig. 6(b) are diagrams in which the liquid crystal display panel 11 and the diffusion plate 206 are partially omitted in order to explain the light guide 311.

[0085] 6 shows a state in which the LEDs 14 constituting the light source are mounted on a substrate 102. The LEDs 14 and the substrate 102 are attached to a reflector 300 at predetermined positions.

[0086] 6(a), the LEDs 14 are arranged in a row in a direction parallel to the side (short side in this example) of the liquid crystal display panel 11 on which the reflector 300 is arranged. In the example shown in the figure, the reflector 300 is arranged corresponding to the arrangement of the LEDs. Note that a plurality of reflectors 300 may be arranged.

[0087] In one embodiment, the reflectors 300 are each made of a plastic material. Alternatively, the reflectors 300 may be made of a metal material or a glass material, but plastic materials are easier to mold, so in this embodiment, plastic materials are used.

[0088] 6(b), the inner surface (right side in the figure) of the reflector 300 has a reflecting surface (hereinafter sometimes referred to as a "paraboloid") 305 shaped like a paraboloid cut at its meridian plane. The reflector 300 converts the divergent light emitted from the LED 14 into approximately parallel light by reflecting it off the reflecting surface 305 (paraboloid), and directs the converted light to be incident on an end face of the light guide 311. In one specific example, the light guide 311 is a transmissive light guide.

[0089] The reflecting surface of reflector 300 has a shape asymmetric with respect to the optical axis of the light emitted from LED 14. Furthermore, reflecting surface 305 of reflector 300 is a parabolic surface as described above, and by placing the LED at the focus of this parabolic surface, the light flux after reflection is converted into approximately parallel light.

[0090] Because the LED 14 is a surface light source, even if it is placed at the focus of a parabolic surface, 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. The LED 14 and reflector 300 form a pair. Furthermore, to ensure the specified performance when the LED 14 is attached to the substrate 102 with an accuracy of ±40 μm, the number of LEDs attached to the substrate should be limited to a maximum of 10 or less, and considering mass production, it is best to limit it to around 5.

[0091] Although the LED 14 and reflector 300 are partly close to each other, heat can be dissipated into the space on the opening side of the reflector 300, reducing the temperature rise of the LED. This makes it possible to use a plastic molded reflector 300. As a result, with this reflector 300, the shape precision of the reflective surface can be improved by 10 times or more compared to a reflector made of glass material, thereby improving light utilization efficiency.

[0092] On the other hand, a reflective surface is provided on the bottom surface 303 of the light guide 311, and the light from the LED 14 is converted into a parallel beam by the reflector 300, reflected by the reflective surface, and emitted toward the liquid crystal display panel 11 disposed opposite the light guide 311. As shown in Fig. 6(a), the reflective surface provided on the bottom surface 303 may have a plurality of surfaces with different inclinations in the traveling direction of the parallel beam from the reflector 300. Each of the plurality of surfaces with different inclinations may have a shape extending in a direction perpendicular to the traveling direction of the parallel beam from the reflector 300.

[0093] Furthermore, the shape of the reflective surface provided on bottom surface 303 may be flat. In this case, the light reflected by the reflective surface provided on bottom surface 303 of light guide 311 is refracted by refractive surface 314 provided on the surface of light guide 311 facing liquid crystal display panel 11, making it possible to adjust with high precision the amount of light and the emission direction of the light beam heading toward liquid crystal display panel 11. As a result, the amount of light and the emission direction of light incident on liquid crystal display panel 11 and the emission direction of light emitted from liquid crystal display panel 11 can also be controlled with high precision, so that in a spatial image information display system that uses an image display device that employs this light source, the diffusion direction and diffusion angle of the image light of the spatially floating image can be set to desired values.

[0094] 6(a) and 6(b), the refractive surface 314 may have a plurality of surfaces with different inclinations in the traveling direction of the collimated light beam from the reflector 300. Each of the plurality of surfaces with different inclinations may have a shape extending in a direction perpendicular to the traveling direction of the collimated light beam from the reflector 300. The inclinations of the plurality of surfaces refract the light reflected by the reflective surface provided on the bottom surface 303 of the light guide 311 toward the liquid crystal display panel 11. Alternatively, the refractive surface 314 may be a transmitting surface.

[0095] If a diffuser plate 206 is provided in front of the liquid crystal display panel 11, the light reflected by the reflective surface is refracted toward the diffuser plate 206 due to the multiple inclinations of the refracting surface 314. That is, the extension direction of the multiple surfaces with different inclinations of the refracting surface 314 is parallel to the extension direction of the multiple surfaces with different inclinations of the reflective surface provided on the bottom surface 303. By making the extension directions of both surfaces parallel, the angle of the light can be adjusted more appropriately. On the other hand, the LEDs 14 are soldered to the metallic substrate 102. This allows heat generated by the LEDs to be dissipated into the air via the substrate.

[0096] The reflector 300 may be in contact with the substrate 102, or a space may be left between them. If a space is left between them, the reflector 300 is attached to the housing. By leaving a space between them, heat generated by the LED can be dissipated into the air, improving the cooling effect. As a result, the operating temperature of the LED can be reduced, allowing for the maintenance of luminous efficiency and a longer lifespan.

[0097] <Another example of light source device 2> Next, the configuration of an optical system relating to a light source device that uses polarization conversion to improve light utilization efficiency by 1.8 times compared to the light source device shown in Fig. 6 will be described in detail with reference to Fig. 7A, Fig. 7B, Fig. 7C, and Fig. 7D. Note that sub-reflector 308 is not shown in Fig. 7A.

[0098] 7A, 7B, and 7C show the state in which the LEDs 14 constituting the light source are mounted on the substrate 102, and these are configured as a unit 312 having a plurality of blocks, with the reflector 300 and the LEDs 14 forming a pair of blocks.

[0099] 7A(2) is the base material of the substrate 102. Generally, the metallic substrate 102 generates heat, so it is preferable to use a plastic material or the like for the substrate 320 in order to insulate (heat-insulate) the heat of the substrate 102. The material and shape of the reflecting surface of the reflector 300 may be the same as those of the example of the light source device in FIG.

[0100] The reflecting surface of the reflector 300 may also have an asymmetric shape with respect to the optical axis of the light emitted from the LED 14. The reason for this will be explained with reference to Fig. 7A(2). In this embodiment, the reflecting surface of the reflector 300 is a parabolic surface, as in the example of Fig. 6, and the center of the light emitting surface of the LED, which is a surface light source, is located at the focal position of the parabolic surface.

[0101] Furthermore, due to the characteristics of the parabolic surface, the light emitted from the four corners of the light-emitting surface also becomes approximately parallel light beams, and the only difference is the direction of emission. Therefore, even if the light-emitting part has an area, the amount of light incident on the polarization conversion element 21 and the conversion efficiency are hardly affected as long as the distance between the polarization conversion element 21 and the reflector 300 arranged in the subsequent stage is short.

[0102] Furthermore, even if the mounting position of the LED 14 is shifted in the XY plane with respect to the focal point of the corresponding reflector 300, an optical system can be realized that can reduce the decrease in light conversion efficiency for the reasons described above. Furthermore, even if the mounting position of the LED 14 varies in the Z-axis direction, the converted parallel light beam simply moves in the ZX plane, and the mounting precision of the LED, which is a surface light source, can be significantly reduced. In this embodiment, the reflector 300 having a reflective surface formed by meridionally cutting out a portion of a paraboloid has been described, but the LED may also be placed in a portion of the cutout with the entire paraboloid as the reflective surface.

[0103] 7B(1) and 7C, the present embodiment is characterized in that the divergent light from the LED 14 is reflected by the parabolic surface 321 and converted into approximately parallel light, and then the parallel light is incident on the end face of the polarization conversion element 21 at the subsequent stage, and aligned into a specific polarization by the polarization conversion element 21. With this characteristic configuration, the present embodiment achieves a light utilization efficiency 1.8 times that of the example shown in FIG. 6, thereby realizing a highly efficient light source.

[0104] At this time, the substantially parallel light resulting from the reflection of the divergent light from the LED 14 by the parabolic surface 321 is not all uniform. Therefore, by adjusting the angular distribution of the reflected light by the reflecting surface 307 having multiple inclinations, the light can be made to enter the liquid crystal display panel 11 in a direction perpendicular to the liquid crystal display panel 11.

[0105] In the example shown in this figure, the direction of the light (principal ray) entering the reflector from the LED is approximately parallel to the direction of the light entering the LCD panel. This arrangement is easy to design, and placing the heat source below the light source device is preferable because it allows air to escape upwards, reducing the temperature rise of the LED.

[0106] 70B(1), in order to improve the capture rate of divergent light from LED 14, the light beam that cannot be captured by reflector 300 is reflected by sub-reflector 308 provided on light shielding plate 309 arranged above the reflector, and is reflected by the slope of sub-reflector 310 below to enter the effective area of ​​polarization conversion element 21 in the subsequent stage, thereby further improving the light utilization efficiency. That is, in this embodiment, a part of the light reflected by reflector 300 is reflected by sub-reflector 308, and the light reflected by sub-reflector 308 is reflected by sub-reflector 310 in a direction toward light guide 306.

[0107] The substantially parallel light beam, which has been aligned to a specific polarization by the polarization conversion element 21, is reflected by a reflection shape provided on the surface of the reflective light guide 306 toward the liquid crystal display panel 11 disposed opposite the light guide 306. At this time, the light quantity distribution of the light beam incident on the liquid crystal display panel 11 is optimally designed by the shape and arrangement of the reflector 300 described above, and the shape (cross-sectional shape) of the reflective surface of the reflective light guide, as well as the inclination and surface roughness of the reflective surface.

[0108] The shape of the reflective surface provided on the surface of the light guide 306 is such that multiple reflective surfaces are arranged opposite the exit surface of the polarization conversion element 21, and the inclination, area, height, and pitch of the reflective surfaces are optimized according to the distance from the polarization conversion element 21, thereby making the light intensity distribution of the light beam incident on the liquid crystal display panel 11 a desired value, as described above.

[0109] As shown in FIG. 7B(2), the reflective surface 307 of the reflective light guide can be configured with multiple inclinations on one surface, thereby enabling more precise adjustment of reflected light. Note that the reflective surface can be configured with multiple inclinations on one surface by using a multi-surface, polyhedral, or curved surface. Furthermore, the diffusing effect of the diffuser 206 achieves a more uniform light intensity distribution. Light incident on the diffuser plate closer to the LED can be uniformly distributed by changing the inclination of the reflective surface. As a result, the amount and direction of light beams directed toward the liquid crystal display panel 11 can be precisely adjusted. Therefore, the amount and direction of light incident on and emitted from the liquid crystal display panel 11 can be precisely adjusted. Therefore, in a spatial image information display system using an image display device with this light source, the diffusion direction and diffusion angle of the image light of a floating image can be set to desired values.

[0110] In this embodiment, a plastic material such as heat-resistant polycarbonate is used for the base material of the reflecting surface 307. The angle of the reflecting surface 307 immediately after emission from the λ / 2 plate 213 varies depending on the distance between the λ / 2 plate and the reflecting surface.

[0111] In this embodiment, the LED 14 and the reflector 300 are also partially adjacent to each other, but the temperature rise of the LED can be reduced by dissipating heat into the space on the opening side of the reflector 300. Furthermore, the substrate 102 and the reflector 300 may be arranged upside down compared to those in Figures 7A, 7B, and 7C.

[0112] However, if the substrate 102 is placed on top, the substrate 102 will be close to the liquid crystal display panel 11, which may make the layout difficult. Therefore, as shown in the figure, placing the substrate 102 below the reflector 300 (on the side farther from the liquid crystal display panel 11) will simplify the internal configuration of the device.

[0113] As shown in Figure 7C, a light-shielding plate 410 may be provided on the light-incident surface of the polarization conversion element 21 to prevent unnecessary light from entering the downstream optical system. This configuration achieves a light source device with reduced temperature rise. The polarizer provided on the light-incident surface of the liquid crystal display panel 11 reduces temperature rise by absorbing the uniformly polarized light beam of the present invention. However, when the light is reflected by the reflective light guide, the polarization direction rotates, and some of the light is absorbed by the incident-side polarizer. Furthermore, the temperature of the liquid crystal display panel 11 also rises due to absorption by the liquid crystal itself and light incident on the electrode pattern. However, there is sufficient space between the reflective surface of the reflective light guide 306 and the liquid crystal display panel 11, allowing for natural cooling.

[0114] Fig. 7D is a modified example of the light source device of Fig. 7B(1) and Fig. 7C. Fig. 7D(1) illustrates a modified example of a portion of the light source device of Fig. 7B(1). The other configurations are the same as those of the light source device described above in Fig. 7B(1), so illustrations and repeated explanations will be omitted.

[0115] 7D(1), the height of recess 319 of sub-reflector 310 is adjusted to be lower than phosphor 114 so that the chief ray of fluorescence output laterally (in the X-axis direction) from phosphor 114 (see the straight line extending in a direction parallel to the X-axis in FIG. 7D(1)) can exit from recess 319 of sub-reflector 310. Furthermore, the height of light-shielding plate 410 is adjusted to be lower in the Z-axis direction relative to the position of phosphor 114 so that the chief ray of fluorescence output laterally from phosphor 114 can enter the effective area of ​​polarization conversion element 21 without being blocked by light-shielding plate 410.

[0116] Furthermore, the reflective surface of the convex portion of the uneven top of the sub-reflector 310 reflects the light reflected by the sub-reflector 308 in order to guide the light reflected by the sub-reflector 308 to the light guide 306. Therefore, the height of the convex portion 318 of the sub-reflector 310 is adjusted so that the light reflected by the sub-reflector 308 is reflected and incident on the effective area of ​​the polarization conversion element 21 in the subsequent stage, thereby further improving the light utilization efficiency.

[0117] 7A(2), the sub-reflector 310 is arranged to extend in one direction and has an uneven shape. Furthermore, the top of the sub-reflector 310 has unevenness with one or more recesses periodically arranged in one direction. By using such an uneven shape, it is possible to configure the sub-reflector 310 so that the chief ray of the fluorescence output laterally from the phosphor 114 enters the effective area of ​​the polarization conversion element 21.

[0118] Furthermore, the concave and convex shapes of sub-reflector 310 are periodically arranged at a pitch such that concave portions 319 are located at positions where LEDs 14 are present. That is, each of phosphors 114 is periodically arranged along one direction corresponding to the pitch of the arrangement of concave portions of the concave and convex shapes of sub-reflector 310. Note that when phosphor 114 is provided in LED 14, phosphor 114 may be expressed as a light-emitting portion of the light source.

[0119] 7D(2) illustrates a modified example of a portion of the light source device of FIG. 7C. Other configurations are the same as those of the light source device of FIG. 7C, and therefore illustrations and repeated explanations are omitted. As shown in FIG. 7D(2), the sub-reflector 310 is not necessary, but as in FIG. 7D(1), the height of the light-shielding plate 410 is adjusted to be lower in the Z-axis direction relative to the position of the phosphor 114 so that the chief ray of the fluorescence output laterally from the phosphor 114 is not blocked by the light-shielding plate 410 and enters the effective area of ​​the polarization conversion element 21.

[0120] 7A, 7B, 7C, and 7D, a side wall 400 may be provided as shown in Fig. 7A(1) to prevent dust 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 outside the light source device, and to prevent stray light from entering from outside the light source device. When the side wall 400 is provided, it is arranged so as to sandwich the space between the light guide 306 and the diffuser plate 206.

[0121] The light exit surface of the polarization conversion element 21, which emits light that has been polarization-converted by the polarization conversion element 21, faces the space surrounded by the side wall 400, the light guide 306, the diffuser plate 206, and the polarization conversion element 21. Furthermore, a reflective surface having a reflective film or the like is used for the inner surface of the side wall 400, which partly covers the space into which light is output from the exit surface of the polarization conversion element 21 (the space to the right of the exit surface of the polarization conversion element 21 in FIG. 7B(1)). In other words, the surface of the side wall 400 facing the space has a reflective area having a reflective film. By making this part of the inner surface of the side wall 400 a reflective surface, the light reflected by the reflective surface can be reused as light source light, thereby improving the brightness of the light source device.

[0122] Of the inner surfaces of the side wall 400, the surface that covers the side of the polarization conversion element 21 is made to have low light reflectivity (such as a black surface without a reflective film). This is because if light is reflected from the side surface of the polarization conversion element 21, light with an unexpected polarization state will be generated, causing stray light. In other words, by making the above surface a surface with low light reflectivity, it is possible to prevent or suppress the occurrence of stray light in the image and light with an unexpected polarization state. Furthermore, the side wall 400 may be configured to have holes in parts to allow air to pass through, thereby improving the cooling effect.

[0123] 7A, 7B, 7C, and 7D have been described assuming a configuration using the polarization conversion element 21. However, these light source devices may be configured without the polarization conversion element 21. In this case, a light source device can be provided at a lower cost.

[0124] <Another example of light source device 3> Next, the configuration of the optical system for 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 will be described in detail with reference to Figures 8A(1), (2), (3) and 8B.

[0125] 8A shows a state in which the LEDs 14 constituting the light source are mounted on the substrate 102, and these are configured as a pair of blocks, each consisting of a collimator 18 and an LED 14, and a unit 328 having multiple blocks. Since the collimator 18 in this embodiment is located close to the LED 14, a glass material is used for the collimator 18 in consideration of heat resistance. The shape of the collimator 18 is the same as that described for the collimator 15 in FIG. 7. In addition, by providing a light shielding plate 317 in the stage before the light enters the polarization conversion element 21, it is possible to prevent or suppress unwanted light from entering the optical system in the subsequent stage, thereby reducing the temperature rise caused by the unwanted light.

[0126] Other configurations and effects of the light source shown in Fig. 8A are the same as those in Fig. 7A, Fig. 7B, Fig. 7C, and Fig. 7D, and therefore a repeated explanation will be omitted. The light source device in Fig. 8A may be provided with a side wall, as explained in Fig. 7A, Fig. 7B, and Fig. 7C. The configurations and effects of the side walls have already been explained, and therefore a repeated explanation will be omitted.

[0127] Fig. 8B is a cross-sectional view of Fig. 8A(2). The configuration of the light source shown in Fig. 8B is common to part of the structure of the light source in Fig. 7, and has already been explained in Fig. 18, so repeated explanation will be omitted.

[0128] <Another example of light source device 4> 12 is configured with a unit 328 having a plurality of blocks, each of which is a pair of the collimator 18 and the LED 14 used in the light source device shown in Fig. 8. The configuration of the optical system relating to the light source device using the LEDs and the reflective light guide 504 arranged at both ends of the back surface of the liquid crystal display panel 11 will be described in detail with reference to Figs. 12(a), (b) and (c).

[0129] 12 shows a state in which LEDs 14 constituting a light source are mounted on a substrate 505, and these are configured as units 503 having a plurality of blocks, each of which has a pair of a collimator 18 and an LED 14. The units 503 are arranged at both ends of the rear surface of the liquid crystal display panel 11 (in this embodiment, three units are arranged side by side in the short side direction). Light output from the units 503 is reflected by a reflective light guide 504 arranged opposite to the units 503, and is configured to enter the liquid crystal display panel 11 (shown in FIG. 12(c)).

[0130] As shown in Fig. 12(c), the reflective light guide 504 is divided into two blocks corresponding to the units arranged at each end, and is arranged so that the central part is the highest. Because the collimator 18 is located close to the LED 14, a glass material is used for the collimator 18 in consideration of its heat resistance to the heat emitted from the LED 14. The shape of the collimator 18 is the same as that described for the collimator 15 in Fig. 10.

[0131] Light from LED 14 enters polarization conversion element 501 via collimator 18. The distribution of light entering reflective light guide 504 at the subsequent stage is adjusted by the shape of optical element 81. That is, the light intensity distribution of the light beam entering liquid crystal display panel 11 is optimally designed by adjusting the shape and arrangement of collimator 18 described above, the shape and diffusion characteristics of optical element 81, and the shape (cross-sectional shape) of the reflective surface of the reflective light guide, as well as the inclination of the reflective surface and the surface roughness of the reflective surface.

[0132] As shown in FIG. 12(b), the shape of the reflective surface provided on the surface of the reflective light guide 504 is such that multiple reflective surfaces are arranged opposite the exit surface of the polarization conversion element, and the inclination, area, height, and pitch of the reflective surfaces are optimized according to the distance from the polarization conversion element 21. Furthermore, by dividing the area of ​​the same reflective surface (i.e., the surface facing the polarization conversion element) into a polyhedron, the light intensity distribution of the light beam incident on the liquid crystal display panel 11 can be adjusted (optimized) to a desired value, as described above. This allows the light intensity and exit direction of the light beam toward the liquid crystal display panel 11 to be adjusted with high precision. As a result, the light intensity and exit direction of the light incident on the liquid crystal display panel 11 and the light exiting from the liquid crystal display panel 11 can also be adjusted with high precision. Therefore, in a spatial image information display system using an image display device that employs this light source, the diffusion direction and diffusion angle of the image light of the spatially floating image can be set to desired values.

[0133] 7B, the reflective surface provided on the reflective light guide can adjust the reflected light with higher precision by configuring one surface (the area where light is reflected) to have a shape with multiple inclinations (in the example of FIG. 12, the XY plane is divided into 14 sections with different inclinations), thereby preventing the reflected light from leaking from the side of light source device 13. Also, by providing light-shielding wall 507, it is possible to prevent light from leaking in any direction other than the desired direction (towards liquid crystal display panel 11).

[0134] Furthermore, the units 503 arranged on the left and right sides of the reflective light guide 504 in Fig. 12 may be replaced with the light source device in Fig. 7. That is, a configuration may be adopted in which a plurality of light source devices (substrate 102, reflector 300, LED 14, etc.) in Fig. 7 are prepared and these plurality of light source devices are arranged in positions facing each other, as shown in Figs. 12(a), (b), and (c).

[0135] FIG. 13(B) shows a light source device configured by arranging six units 503 shown in FIG. 13(A) on the top and six units on the bottom. The light source device shown in FIG. 13(B) is configured with units 503, each with five LEDs arranged horizontally, arranged as described above, and the desired brightness is obtained by controlling the current using a single power supply. Therefore, as a light source device for illuminating a liquid crystal panel, the light source brightness can be controlled for each area illuminated by each unit 503. The configuration shown in FIG. 13 includes a reflective surface 222 and a reflective surface 502 different from the reflective surface 222. Of these, the reflective surface 222 has a horizontal lattice-like shape or a strip-like shape with a predetermined width.

[0136] On the other hand, the reflecting surface 502 has a shape resembling a vertical and horizontal grid. By optimally designing the shape of these fine grids and the inclination of the dividing surfaces, a desired distribution of emitted light (emission direction and diffusion characteristics of emitted light) can be obtained. This makes it possible to adjust the amount of light and emission direction of the light beam heading toward the liquid crystal display panel 11 with high precision. As a result, similar to the two embodiments described above, the amount of light and emission direction of the light incident on the liquid crystal display panel 11 and the light emitted from the liquid crystal display panel 11 can be controlled with high precision in the same way. Therefore, in a spatial image information display system using an image display device that employs this light source, the diffusion direction and diffusion angle of the image light of the spatially floating image can be set to desired values.

[0137] 9 is a cross-sectional view showing an example of the shape of the diffuser plate 206. As described above, the divergent light output from the LED is converted into approximately parallel light by the reflector 300 or the collimator 18, converted into specific polarization by the polarization conversion element 21, and then reflected by the light guide. The light beam reflected by the light guide then passes through the flat portion of the incident surface of the diffuser plate 206 and enters the liquid crystal display panel 11 (see the two solid arrows indicating "reflected light from the light guide" in FIG. 9).

[0138] Furthermore, of the light emitted from the polarization conversion element 21, the divergent light beam is totally reflected by the inclined surfaces of the protrusions having inclined surfaces provided on the incident surface of the diffuser plate 206, and then enters the liquid crystal display panel 11. In order to totally reflect the light emitted from the polarization conversion element 21 by the inclined surfaces of the protrusions of the diffuser plate 206, the angle of the inclined surfaces of the protrusions is changed based on the distance from the polarization conversion element 21. If the angle of the inclined surface of the protrusions on the side farther from the polarization conversion element 21 or farther from the LEDs is α, and the angle of the inclined surface of the protrusions on the side closer to the polarization conversion element 21 or closer to the LEDs is α', then α is smaller than α' (α<α'). By setting in this way, it becomes possible to effectively utilize the polarization-converted light beam.

[0139] <Technology for controlling diffusion characteristics of video display devices> One method for adjusting the diffusion distribution of the image light from the liquid crystal display panel 11 is to provide a lenticular lens 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 optimize the shape of the lens. That is, by optimizing the shape of the lenticular lens, it is possible to adjust the emission characteristics of the image light (hereinafter also referred to as "image luminous flux") emitted in one direction from the liquid crystal display panel 11.

[0140] 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 may be adjusted. That is, by adjusting the arrangement of the microlens array, it is possible to adjust the emission characteristics in the X-axis and Y-axis directions of the image light beam emitted from the image display device 1, and as a result, it is possible to obtain an image display device with desired diffusion characteristics.

[0141] As a further configuration example, two lenticular lenses may be combined and arranged at a position where the image light emitted from the image display device 1 passes, or a sheet for adjusting the diffusion characteristics by arranging a microlens array in a matrix may be provided. By configuring the optical system in this way, the brightness (relative brightness) of the image light in the X-axis and Y-axis directions can be adjusted according to the reflection angle of the image light (reflection angle with the vertical reflection as the reference (0 degrees)).

[0142] In this example, by using such a lenticular lens, it is possible to obtain excellent optical characteristics that are clearly different from the graphs (plot curves) of conventional characteristics, as shown in the graphs (plot curves) of "Example 1 (Y direction)" and "Example 2 (Y direction)" in Figure 16(b). Specifically, in the plot curves of Example 1 (Y direction) and Example 2 (Y direction), the brightness characteristic in the vertical direction is made steeper, and further, by changing the balance of the directional characteristics in the up and down direction (positive and negative directions of the Y axis), it is possible to increase the brightness (relative brightness) of light due to reflection and diffusion.

[0143] Therefore, according to this embodiment, the image light has a narrow diffusion angle (high straightness) and contains only specific polarization components, like the image light from a surface-emitting laser image source, and can be adjusted to suppress the ghost images that would occur in the retroreflective member when using an image display device using conventional technology, and to efficiently deliver the spatially floating image caused by retroreflection to the viewer's eyes.

[0144] Furthermore, the light source device described above can provide a directional characteristic with a significantly narrower angle in both the X-axis and Y-axis directions compared to the diffusion characteristic of light emitted from a general liquid crystal display panel shown in Figures 17(A) and 17(B) (indicated as "conventional characteristic" in the figures). In this embodiment, by providing such a narrow-angle directional characteristic, it is possible to realize an image display device that emits light of a specific polarization, emitting an image light beam that is nearly parallel in a specific direction.

[0145] FIG. 17 shows an example of the characteristics of the lenticular lens employed in this embodiment. This example particularly shows the characteristics in the X direction (vertical direction) relative to the Z axis. Characteristic O shows a luminance characteristic that is symmetrical vertically, with the peak of the light emission direction at an angle of approximately 30 degrees upward from the vertical direction (0 degrees). Furthermore, the plot curves of characteristic A and characteristic B shown in the graph of FIG. 17 show examples of characteristics in which the image light above the peak luminance is further concentrated at approximately 30 degrees, thereby increasing the luminance (relative luminance). Therefore, in characteristic A and characteristic B, as can be seen by comparing them with the plot curve of characteristic O, the luminance (relative luminance) of light drops sharply in the region where the inclination (angle θ) from the Z axis to the X direction exceeds 30 degrees (θ>30°).

[0146] That is, with the optical system including the lenticular lens described above, when the image light beam from the image display device 1 is incident on the retroreflective member, the emission angle and viewing angle of the image light aligned to a narrow angle by the light source device 13 can be adjusted, significantly improving the flexibility of retroreflective sheet installation. As a result, the flexibility of the image position relationship of the spatially floating image that is reflected or transmitted through the window glass and focused at the desired position can be significantly improved. As a result, it is possible to efficiently deliver light with a narrow diffusion angle (high linearity) and only specific polarization components to the eyes of viewers indoors or outdoors. As a result, even if the intensity (brightness) of the image light from the image display device 1 is reduced, viewers can accurately recognize the image light and obtain information. In other words, by reducing the output of the image display device 1, it is possible to realize an information display system with low power consumption.

[0147] Various embodiments or examples (i.e., specific examples) to which the present invention is applied have been described in detail above. However, the present invention is not limited to the above-described embodiments (specific examples) and includes various modifications. For example, the above-described embodiments are detailed descriptions of the entire system to clearly explain the present invention, and are not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0148] The light source device described above is not limited to the space floating image display device, but can also be applied to information display devices such as HUDs, tablets, digital signage, and the like.

[0149] The technology according to this embodiment displays high-resolution, high-brightness floating images in a floating state, allowing users to operate the system without worrying about contact infection. Using the technology according to this embodiment in a system used by an unspecified number of users reduces the risk of contact infection and provides a contactless user interface that can be used without anxiety. The present invention, which provides such technology, contributes to the "Good Health and Well-Being" goal, one of the Sustainable Development Goals (SDGs) advocated by the United Nations.

[0150] Furthermore, the technology according to the above-described embodiment reduces the divergence angle of the emitted image light and aligns it with a specific polarization, thereby efficiently reflecting only the normal reflected light from the retroreflective material, thereby achieving high light utilization efficiency and producing bright and clear floating images in space. The technology according to the present embodiment can provide a highly usable non-contact user interface that can significantly reduce power consumption. The present invention, which provides such technology, contributes to the achievement of the United Nations' Sustainable Development Goals (SDGs): "Build resilient infrastructure, promote inclusive and sustainable industrialization, and promote technological innovation and infrastructure" and "Make cities and human settlements sustainable."

[0151] Furthermore, the technology according to the above-described embodiment makes it possible to form a floating image in space using highly directional (linear) image light. The technology according to this embodiment makes it possible to provide a non-contact user interface with low risk of people other than the user peeking at the floating image, even when displaying images that require high security, such as those in bank ATMs or train station ticket machines, or highly confidential images that should be kept secret from people directly facing the user, by displaying highly directional image light. By providing the above-described technology, the present invention contributes to "Sustainable Cities and Communities," one of the Sustainable Development Goals (SDGs) advocated by the United Nations. [Explanation of symbols]

[0152] 1...image display device, 2...first retroreflective member, A1, A2, 3, 220A, 220B, 204...spatial image (space-floating image), 110...first transmissive plate, 111...reflective polarizing sheet, (reflective polarizing plate) 13...light source device, 54...light direction conversion panel, 105...linear Fresnel sheet, 107...rotation mechanism, 102...absorptive polarizing sheet (absorptive polarizing plate), 200...flat display, 201...casing, 203...sensing system, 226...sensing area, 102...substrate, 11, 335...liquid crystal display panel, 206...diffuser, 21...polarization conversion element, 300...reflector, 213...λ / 2 plate, 306...reflective light guide, 307...reflective surface, 308, 310...sub-reflector, 204...space floating image, 334...image light control sheet, 336...transmitting section, 337...light absorbing section, 81...optical element, 501...polarization conversion element, 503...unit, 507...light shielding wall, 401, 402...light shielding plate, 320...substrate, 511...casing, 512...support arm, 513...hinge, 514...back cover, 515...casing cover, 516...casing base, 517, 518...inclined linear Fresnel sheet, 519...eccentric Fresnel sheet

Claims

1. A space floating image information display system, a display panel that emits image light; a light source device that supplies light to the display panel; a retroreflective member that displays a real image floating in space in the air using image light of a specific polarization from the display panel; a polarization conversion member that converts image light of a specific polarization into another polarization is provided on the surface of the retroreflective member; a first transmissive plate provided between the display panel and the retroreflective member, the first transmissive plate having a polarizing beam splitter that transmits image light of a specific polarized wave and reflects image light that has been converted into another polarized wave after being reflected by the retroreflective member; a second transparent plate provided with a polarizing plate sheet and disposed at the opening of the housing of the space floating image information display system; The image light converted into the other polarized wave after being reflected by the retroreflective member is reflected in a direction substantially perpendicular to an optical axis connecting the display panel and the retroreflective member disposed opposite the display panel, The reflected image light passes through the second transmissive plate provided with the polarizing plate sheet, and then displays a real image floating in space. A floating visual information display system.

2. 2. The space floating image information display system according to claim 1, The display panel, the light source device, the retroreflective member, and the first transmissive plate are incorporated into the housing and connected by a member that couples with a part of the housing. A floating visual information display system.

3. 2. The space floating image information display system according to claim 1, a structure for changing the distance between the display panel and the first transmissive plate; A floating visual information display system.

4. 2. The space floating image information display system according to claim 1, the first transparent plate is fixed to the housing via an elastic member; A floating visual information display system.

5. 5. The space floating image information display system according to claim 4, A light-emitting unit and a light-receiving unit of a sensing system for manipulating and interacting with the floating image in space are provided inside the housing. A floating visual information display system.

6. 2. The space floating image information display system according to claim 1, The light source device is a point or surface light source; a reflector that reflects light from the light source; a light guide that guides the light from the reflector toward the display panel, The reflecting surface of the reflector has an asymmetric shape with respect to the optical axis of the light emitted from the light source. A floating visual information display system.

7. 7. The space floating image information display system according to claim 6, The light guide is a reflective light guide. A floating visual information display system.

8. 8. The space floating image information display system according to claim 6 or 7, a diffusion plate that diffuses light from the light guide; and side walls arranged to sandwich a space between the light guide and the diffusion plate. A floating visual information display system.

9. 7. The space floating image information display system according to claim 6, The reflector is made of a plastic material, a glass material, or a metal material. A floating visual information display system.

Images