Floating image display device

Abstract

To provide a suitable aerial floating video display device.SOLUTION: The aerial floating video display device comprises a video display unit that displays a video, a retroreflective plate which a light flux from the video display unit enters, an imaging unit, and a control unit, the light flux having been reflected at the retroreflective plate forming an aerial floating video in the air that is a real image. The control unit is capable of setting the virtual position of a 3D model against the aerial floating video that is a real image, and the video display unit displays a video that has resulted from the rendering process of 3D data of the 3D model based on a user's viewpoint position detected on the basis of the captured image having been captured by the imaging unit and the virtual position of the 3D model, with a video for binocular vision due to motion parallax being displayed in the aerial floating video. The virtual position of the 3D model is the position shifted, with respect to the position of the aerial floating video that is a real image formed in the air, in a direction that is reverse to the direction of travel of a main beam of light when the light flux having been reflected at the retroreflective plate forms the aerial floating video.SELECTED DRAWING: Figure 15A

Description

[Technical Field]

[0001] The present invention relates to a floating-in-the-air image display device. [Background technology]

[0002] The floating information display technology is disclosed in, for example, 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] However, the disclosure of Patent Document 1 does not sufficiently consider a configuration for obtaining practical brightness and quality for the floating image, or a configuration for allowing the user to view the floating image more enjoyably.

[0005] An object of the present invention is to provide a more suitable floating-in-the-air image display device. [Means for solving the problem]

[0006] To solve the above problem, for example, the configuration described in the claims is adopted. The present application includes multiple means for solving the above problem, but one example thereof may include a video display unit that displays an image, a retroreflector onto which a light beam from the video display unit is incident, an imaging unit, and a control unit, wherein the light beam reflected by the retroreflector forms a floating-in-the-air image that is a real image in the air, the control unit is capable of setting a virtual position of a 3D model relative to the floating-in-the-air image that is a real image, the video display unit displays an image that is the result of a rendering process of 3D data of the 3D model based on the user's viewpoint position detected based on the captured image captured by the imaging unit and the virtual position of the 3D model, and an image for stereoscopic viewing due to motion parallax of the 3D model is displayed in the floating-in-the-air image that is a real image, and the virtual position of the 3D model set by the control unit is shifted in a direction opposite to the traveling direction of a chief ray when the light beam reflected by the retroreflector forms the floating-in-the-air image with respect to the position of the floating-in-the-air image that is a real image formed in the air. [Effects of the Invention]

[0007] According to the present invention, a more suitable floating-in-the-air image display device can be realized. Other problems, configurations, and effects will become clear in the following description of the embodiments. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram showing an example of a usage form of a space floating image display device according to an embodiment of the present invention; [Figure 2A] 1 is a diagram showing an example of a main part configuration and a retroreflection part configuration of a space floating image display device according to an embodiment of the present invention; [Figure 2B] 1 is a diagram showing an example of a main part configuration and a retroreflection part configuration of a space floating image display device according to an embodiment of the present invention; [Figure 2C] 1 is a diagram showing an example of a main part configuration and a retroreflection part configuration of a space floating image display device according to an embodiment of the present invention; [Figure 3]1 is a diagram showing an example of the configuration of a space floating image display device according to an embodiment of the present invention; [Figure 4A] 1 is a diagram showing an example of the configuration of a space floating image display device according to an embodiment of the present invention; [Figure 4B] 1 is a diagram showing an example of the configuration of a space floating image display device according to an embodiment of the present invention; [Figure 4C] 1 is a diagram showing an example of the configuration of a space floating image display device according to an embodiment of the present invention; [Figure 4D] 1 is a diagram showing an example of the configuration of a space floating image display device according to an embodiment of the present invention; [Figure 4E] 1 is a diagram showing an example of the configuration of a space floating image display device according to an embodiment of the present invention; [Figure 4F] 1 is a diagram showing an example of the configuration of a space floating image display device according to an embodiment of the present invention; [Figure 4G] 1 is a diagram showing an example of the configuration of a space floating image display device according to an embodiment of the present invention; [Figure 4H] 1 is a diagram showing an example of the configuration of a space floating image display device according to an embodiment of the present invention; [Figure 4I] 1 is a diagram showing an example of the configuration of a space floating image display device according to an embodiment of the present invention; [Figure 4J] 1 is a diagram showing an example of the configuration of a space floating image display device according to an embodiment of the present invention; [Figure 4K] 1 is a diagram showing an example of the configuration of a space floating image display device according to an embodiment of the present invention; [Figure 4L] 1 is a diagram showing an example of the configuration of a space floating image display device according to an embodiment of the present invention; [Figure 4M] 1 is a diagram showing an example of the configuration of a space floating image display device according to an embodiment of the present invention; [Figure 5] 1 is a cross-sectional view showing an example of a specific configuration of a light source device according to an embodiment of the present invention. [Figure 6] 1 is a cross-sectional view showing an example of a specific configuration of a light source device according to an embodiment of the present invention. [Figure 7]1 is a cross-sectional view showing an example of a specific configuration of a light source device according to an embodiment of the present invention. [Figure 8] 1 is a layout diagram showing a main part of a space floating image display device according to an embodiment of the present invention; [Figure 9] 1 is a cross-sectional view showing a configuration of a display device according to an embodiment of the present invention. [Figure 10] 1 is a cross-sectional view showing a configuration of a display device according to an embodiment of the present invention. [Figure 11] 1 is an explanatory diagram for explaining the light source diffusion characteristics of an image display device according to an embodiment of the present invention. [Figure 12] 1 is an explanatory diagram for explaining the diffusion characteristics of a video display device according to an embodiment of the present invention; [Figure 13A] 1 is a diagram illustrating an example of a problem to be solved by image processing according to an embodiment of the present invention; [Figure 13B] FIG. 10 is an explanatory diagram of an example of image processing according to an embodiment of the present invention. [Figure 13C] FIG. 10 is an explanatory diagram of an example of a video display process according to an embodiment of the present invention. [Figure 13D] FIG. 10 is an explanatory diagram of an example of a video display process according to an embodiment of the present invention. [Figure 14A] 1 is a diagram showing an example of the configuration of a space floating image display device according to an embodiment of the present invention; [Figure 14B] 1 is a diagram showing an example of the configuration of a space floating image display device according to an embodiment of the present invention; [Figure 14C] 1 is a diagram showing an example of the configuration of a space floating image display device according to an embodiment of the present invention; [Figure 15A] 1 is a diagram showing an example of the configuration of a space floating image display device according to an embodiment of the present invention; [Figure 15B] 1 is a diagram showing an example of the configuration of a space floating image display device according to an embodiment of the present invention; [Figure 15C] 1 is a diagram showing an example of the configuration of a space floating image display device according to an embodiment of the present invention; [Figure 15D] 1 is a diagram showing an example of the configuration of a space floating image display device according to an embodiment of the present invention; [Figure 15E] 1 is an explanatory diagram comparing an example of the configuration of a space floating image display device according to an embodiment of the present invention with another comparative example; [Figure 15F] 1 is a diagram showing an example of the configuration of a space floating image display device according to an embodiment of the present invention; 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 description of the embodiments, and various changes and modifications can be made by those skilled in the art within the scope of the technical ideas disclosed in this specification. Furthermore, in all drawings used to explain the present invention, components having the same functions are given the same reference numerals, and repeated explanations thereof may be omitted.

[0010] The following examples relate to an image display device that can transmit an image generated by image light from an image light source through a transparent member that separates a space, such as glass, and display the image as a floating image outside the transparent member. In the following explanation of the examples, the image floating in space is expressed using the term "floating image in space." Instead of this term, it is also acceptable to express it as "aerial image," "spatial image," "floating image in space," "floating optical image of displayed image," "floating optical image of displayed image," etc. The term "floating image in space," which is mainly used in the explanation of the examples, is used as a representative example of these terms.

[0011] According to the following embodiments, an image display device suitable for, for example, bank ATMs, train station ticket machines, digital signage, and the like can be realized. For example, currently, bank ATMs, train station ticket machines, and the like typically use touch panels. However, by using a transparent glass surface or a light-transmitting plate, high-resolution image information can be displayed in a floating state on the glass surface or light-transmitting plate. In this case, by making the divergence angle of the emitted image light small, i.e., an acute angle, and further aligning it with a specific polarization, only the normal reflected light is efficiently reflected by the retroreflector. This improves light utilization efficiency and suppresses the ghost images that occur in addition to the main floating image, which is a problem with conventional retroreflection systems, thereby achieving a clear floating image. Furthermore, by using a device including the light source of this embodiment, a novel and highly usable floating image display device (floating image display system) can be provided that can significantly reduce power consumption. Furthermore, a floating image display device for a vehicle can be provided that can display a so-called unidirectional floating image that can be viewed inside and / or outside the vehicle. Example 1

[0012] <Example of how to use the space floating image display device> FIG. 1 is a diagram showing an example of a usage form of a space-floating image display device according to an embodiment of the present invention, and is a diagram showing the overall configuration of the space-floating image display device according to this embodiment. The specific configuration of the space-floating image display device will be described in detail using FIG. 2 and other figures. Light with a narrow-angle directional characteristic and specific polarization is emitted from image display device 1 as an image light beam, reflected by the optical system within the space-floating image display device, and then incident on retroreflector 2. It is then retroreflected and transmitted through transparent member 100 (glass, etc.), forming a real aerial image (space-floating image 3) on the outside of the glass surface. In the following embodiments, the retroreflector 2 (retroreflector) is used as an example of a retroreflector. However, the retroreflector 2 of the present invention is not limited to a planar plate, and is used as an example of a concept including a sheet-like retroreflector attached to a planar or non-planar member, or an entire assembly in which a sheet-like retroreflector is attached to a planar or non-planar member.

[0013] In addition, in a store or the like, a space is partitioned by a show window (also called "window glass") 105, which is a translucent member such as glass. According to the space floating image display device of this embodiment, it is possible to transmit such a transparent member and display a floating image in one direction to the outside and / or inside of the store (space).

[0014] 1, the inside of the window glass 105 (inside the store) is shown in the depth direction, and the outside (for example, the sidewalk) is shown in the foreground. On the other hand, by providing a means for reflecting specific polarized waves on the window glass 105, it is possible to reflect the waves and form an aerial image at a desired position inside the store.

[0015] <Configuration example of optical system for space floating image display device> 2A is a diagram showing an example of the configuration of an optical system of a space-floating image display device according to one embodiment of the present invention. The configuration of the space-floating image display device will be described in more detail using FIG. 2A. As shown in FIG. 2A(1), a display device 1 that diverges specific polarized image light at a narrow angle is provided in an oblique direction of a transparent member 100 such as glass. The display device 1 includes a liquid crystal display panel 11 and a light source device 13 that generates specific polarized light with narrow-angle diffusion characteristics.

[0016] Image light of a specific polarization from the display device 1 is reflected by a polarization separator 101 (in the figure, the polarization separator 101 is formed into a sheet and adhered to the transparent member 100) that has a film that selectively reflects image light of a specific polarization and is provided on a transparent member 100, and then enters the retroreflector 2. A λ / 4 plate 21 is provided on the image light incident surface of the retroreflector 2. The image light passes through the λ / 4 plate 21 twice, once when it enters the retroreflector 2 and once when it exits, thereby undergoing polarization conversion from the specific polarization to the other polarization. Here, the polarization separator 101 that selectively reflects image light of a specific polarization has the property of transmitting the polarized light of the other polarization that has been polarization-converted, so the image light of the specific polarization after polarization conversion passes through the polarization separator 101. The image light that has passed through the polarization separator 101 forms a space-floating image 3, which is a real image, outside the transparent member 100.

[0017] Here, a first example of polarization design for the optical system of FIG. 2A will be described. For example, S-polarized image light may be emitted from display device 1 to polarization separator 101, which may have the property of reflecting S-polarized light and transmitting P-polarized light. In this case, the S-polarized image light reaching polarization separator 101 from display device 1 is reflected by polarization separator 101 and travels toward retroreflector 2. When the image light is reflected by retroreflector 2, it passes twice through λ / 4 plate 21 provided on the incident surface of retroreflector 2, converting the image light from S-polarized light to P-polarized light. The P-polarized image light then travels back toward polarization separator 101. Here, polarization separator 101 has the property of reflecting S-polarized light and transmitting P-polarized light, so the P-polarized image light passes through polarization separator 101 and then through transparent member 100. The image light transmitted through the transparent member 100 is light generated by the retroreflector 2, and therefore forms a floating image 3, which is an optical image of the image displayed on the display device 1, at a position that is in a mirror relationship with the image displayed on the display device 1 relative to the polarization separation member 101. This polarization design allows the floating image 3 to be formed optimally.

[0018] Next, a second example of polarization design for the optical system of FIG. 2A will be described. For example, a configuration may be adopted in which P-polarized image light is emitted from display device 1 to polarization separator 101, and polarization separator 101 has the property of reflecting P-polarized light and transmitting S-polarized light. In this case, the P-polarized image light that reaches polarization separator 101 from display device 1 is reflected by polarization separator 101 and travels toward retroreflector 2. When the image light is reflected by retroreflector 2, it passes twice through λ / 4 plate 21 provided on the incident surface of retroreflector 2, thereby converting the P-polarized image light to S-polarized light. The S-polarized image light then travels back toward polarization separator 101. Here, polarization separator 101 has the property of reflecting P-polarized light and transmitting S-polarized light, so the S-polarized image light passes through polarization separator 101 and then through transparent member 100. The image light transmitted through the transparent member 100 is light generated by the retroreflector 2, and therefore forms a floating image 3, which is an optical image of the image displayed on the display device 1, at a position that is in a mirror relationship with the image displayed on the display device 1 relative to the polarization separation member 101. This polarization design allows the floating image 3 to be formed optimally.

[0019] The light that forms the floating image 3 is a collection of light rays that converge from the retroreflector 2 to the optical image of the floating image 3, and these light rays continue to travel in a straight line even after passing through the optical image of the floating image 3. Therefore, the floating image 3 is a highly directional image, unlike the diffused image light formed on a screen by a general projector or the like. Therefore, in the configuration of FIG. 2A, when a user views the floating image 3 from the direction of arrow A, the floating image 3 is perceived as a bright image. However, when another person views the floating image 3 from the direction of arrow B, the floating image 3 cannot be perceived as an image at all. This characteristic is very suitable for use in a system that displays images that require high security or highly confidential images that should be kept secret from people directly facing the user.

[0020] Depending on the performance of the retroreflector 2, the polarization axis of the reflected image light may become irregular. The reflection angle may also become irregular. Such irregular light may not maintain the polarization state and propagation angle assumed in the design. For example, light with an unintended polarization state and propagation angle may re-enter the image display surface of the liquid crystal display panel 11 directly from the position of the retroreflector 2 without passing through a polarization separation member. Such light with an unintended polarization state and propagation angle may re-enter the image display surface of the liquid crystal display panel 11 after being reflected by components within the space-floating image display device. Such light re-entering the image display surface of the liquid crystal display panel 11 may be re-reflected by the image display surface of the liquid crystal display panel 11 constituting the display device 1, potentially generating ghost images and degrading the image quality of the space-floating image. Therefore, in this embodiment, an absorbing polarizer 12 may be provided on the image display surface of the display device 1. The image light emitted from the display device 1 is transmitted through the absorptive polarizer 12, and the reflected light returning from the polarization separation member 101 is absorbed by the absorptive polarizer 12, thereby suppressing the re-reflection. This makes it possible to prevent degradation of image quality due to ghost images of spatially floating images. Specifically, if the display device 1 is configured to emit S-polarized image light to the polarization separation member 101, the absorptive polarizer 12 may be a polarizer that absorbs P-polarized light. Furthermore, if the display device 1 is configured to emit P-polarized image light to the polarization separation member 101, the absorptive polarizer 12 may be a polarizer that absorbs S-polarized light.

[0021] The polarization separation member 101 may be formed of, for example, a reflective polarizing plate or a metal multilayer film that reflects specific polarized waves.

[0022] Next, Figure 2A(2) shows the surface shape of a retroreflector manufactured by Nippon Carbide Industries Co., Ltd., which was used in this study as a representative retroreflector 2. Light rays incident on the regularly arranged hexagonal prisms are reflected by the walls and bottoms of the hexagonal prisms and emitted as retroreflected light in a direction corresponding to the incident light, and a real floating image is displayed based on the image displayed on the display device 1.

[0023] The resolution of this floating image in space depends not only on the resolution of the liquid crystal display panel 11, but also on the outer diameter D and pitch P of the retroreflective portion of the retroreflector 2 shown in Figure 2A(2). For example, when using a 7-inch WUXGA (1920 x 1200 pixels) liquid crystal display panel, even if one pixel (one triplet) is approximately 80 μm, if the diameter D of the retroreflective portion is 240 μm and the pitch is 300 μm, one pixel of the floating image in space will be equivalent to 300 μm. As a result, the effective resolution of the floating image in space will be reduced to about one-third.

[0024] Therefore, in order to make the resolution of the spatial floating image equivalent to that of the display device 1, it is desirable to make the diameter and pitch of the retroreflective portion close to one pixel of the liquid crystal display panel. On the other hand, to suppress the occurrence of moire caused by the retroreflective plate and the pixels of the liquid crystal display panel, it is advisable to design the pitch ratio of each to be a different integer multiple of one pixel. Also, it is advisable to arrange the shape so that none of the sides of the retroreflective portion overlaps with any of the sides of one pixel of the liquid crystal display panel.

[0025] The surface shape of the retroreflector according to this embodiment is not limited to the above example. Various surface shapes that achieve retroreflection may be used. Specifically, the surface of the retroreflector according to this embodiment may be provided with retroreflection elements in which triangular pyramidal prisms, hexagonal pyramidal prisms, other polygonal prisms, or a combination of these are periodically arranged. Alternatively, the surface of the retroreflector according to this embodiment may be provided with retroreflection elements in which these prisms are periodically arranged to form cube corners. Alternatively, the surface of the retroreflector according to this embodiment may be provided with capsule lens-type retroreflection elements in which glass beads are periodically arranged. The detailed configuration of these retroreflection elements can be achieved using existing technology, so a detailed description will be omitted. Specifically, the techniques disclosed in Japanese Patent Laid-Open Nos. 2001-33609, 2001-264525, 2005-181555, 2008-70898, and 2009-229942 may be used.

[0026] <Another configuration example 1 of the optical system of the space floating image display device> Another example of the configuration of the optical system of the space floating image display device will be explained using Fig. 2B. In Fig. 2B, components with the same reference numerals as Fig. 2A have the same functions and configurations as Fig. 2A. For the sake of simplicity, repeated explanations of such components will be omitted.

[0027] In the optical system of FIG. 2B, as in FIG. 2A, image light of a specific polarization is output from the display device 1. The image light of a specific polarization output from the display device 1 is input to a polarization separator 101B. The polarization separator 101B is a member that selectively transmits image light of a specific polarization. Unlike the polarization separator 101 of FIG. 2A, the polarization separator 101B is not integrated with the transparent member 100 but has an independent plate-like shape. Therefore, the polarization separator 101B may also be referred to as a polarization separator plate. The polarization separator 101B may be configured as a reflective polarizer configured by attaching a polarization separator sheet to a transparent member. Alternatively, the transparent member may be formed of a metal multilayer film that selectively transmits specific polarization and reflects polarization of other specific polarizations. In FIG. 2B, the polarization separator 101B is configured to transmit image light of a specific polarization output from the display device 1.

[0028] The image light that has passed through the polarization separation member 101B is incident on the retroreflector 2. A λ / 4 plate 21 is provided on the image light incident surface of the retroreflector. The image light is polarized and converted from a specific polarization to the other polarization by passing through the λ / 4 plate 21 twice, once when it enters the retroreflector and once when it leaves. Here, the polarization separation member 101B has the property of reflecting the polarized light of the other polarization that has been polarized and converted by the λ / 4 plate 21, so the image light after polarization conversion is reflected by the polarization separation member 101B. The image light reflected by the polarization separation member 101B passes through the transparent member 100 and forms a space-floating image 3, which is a real image, outside the transparent member 100.

[0029] Here, a first example of polarization design for the optical system of FIG. 2B will be described. For example, a configuration may be adopted in which P-polarized image light is emitted from display device 1 to polarization separator 101B, and polarization separator 101B has the property of reflecting S-polarized light and transmitting P-polarized light. In this case, the P-polarized image light that reaches polarization separator 101B from display device 1 passes through polarization separator 101B and proceeds to retroreflector 2. When the image light is reflected by retroreflector 2, it passes twice through λ / 4 plate 21 provided on the incident surface of retroreflector 2, thereby converting the P-polarized image light to S-polarized light. The S-polarized image light then proceeds again to polarization separator 101B. Here, polarization separator 101B has the property of reflecting S-polarized light and transmitting P-polarized light, so the S-polarized image light is reflected by polarization separator 101 and passes through transparent member 100. The image light transmitted through the transparent member 100 is light generated by the retroreflector 2, and therefore forms a space-floating image 3, which is an optical image of the image displayed on the display device 1, at a position that is in a mirror relationship with the image displayed on the display device 1 relative to the polarization separation member 101B. This polarization design allows the space-floating image 3 to be formed optimally.

[0030] Next, a second example of polarization design for the optical system of FIG. 2B will be described. For example, S-polarized image light may be emitted from display device 1 to polarization separator 101B, which may have the property of reflecting P-polarized light and transmitting S-polarized light. In this case, the S-polarized image light reaching polarization separator 101B from display device 1 passes through polarization separator 101B and proceeds to retroreflector 2. When the image light is reflected by retroreflector 2, it passes twice through λ / 4 plate 21 provided on the incident surface of retroreflector 2, converting the image light from S-polarized light to P-polarized light. The P-polarized image light then proceeds again to polarization separator 101B. Here, polarization separator 101B has the property of reflecting P-polarized light and transmitting S-polarized light, so the P-polarized image light is reflected by polarization separator 101 and passes through transparent member 100. The image light transmitted through the transparent member 100 is light generated by the retroreflector 2, and therefore forms a space-floating image 3, which is an optical image of the image displayed on the display device 1, at a position that is in a mirror relationship with the image displayed on the display device 1 relative to the polarization separation member 101B. This polarization design allows the space-floating image 3 to be formed optimally.

[0031] In FIG. 2B , the image display surface of the display device 1 and the surface of the retroreflector 2 are arranged parallel to each other. The polarization separator 101B is arranged tilted at an angle α (e.g., 30°) relative to the image display surface of the display device 1 and the surface of the retroreflector 2. When the polarization separator 101B reflects the image light, the direction of the image light reflected by the polarization separator 101B (the direction of the chief ray of the image light) differs by an angle β (e.g., 60°) from the direction of the image light incident from the retroreflector 2 (the direction of the chief ray of the image light). With this configuration, the optical system of FIG. 2B outputs the image light toward the outside of the transparent member 100 at a predetermined angle shown in the figure, forming the space-floating image 3, which is a real image. In the configuration of FIG. 2B , when a user views the space-floating image 3 from the direction of arrow A, the space-floating image 3 is perceived as a bright image. However, when another person views the space-floating image 3 from the direction of arrow B, the space-floating image 3 cannot be perceived as an image at all. This characteristic is extremely suitable for use in a system that displays images that require high security or highly confidential images that should be kept secret from people directly facing the user.

[0032] As described above, the optical system of FIG. 2B has a different configuration from the optical system of FIG. 2A, but can form a suitable floating image in space, similar to the optical system of FIG. 2A.

[0033] An absorptive polarizing plate may be provided on the surface of the transparent member 100 facing the polarization separation member 101B. This absorptive polarizing plate may transmit the polarized waves of the image light from the polarization separation member 101B and absorb the polarized waves that are 90° out of phase with the polarized waves of the image light from the polarization separation member 101B. In this way, the image light for forming the space-floating image 3 can be sufficiently transmitted while reducing the external light incident on the space-floating image 3 side of the transparent member 100 by approximately 50%. This makes it possible to reduce stray light in the optical system of FIG. 2B due to the external light incident on the space-floating image 3 side of the transparent member 100.

[0034] <Another configuration example 2 of the optical system of the space floating image display device> Another example of the configuration of the optical system of the space floating image display device will be explained using Fig. 2C. In Fig. 2C, components with the same reference numerals as Fig. 2B have the same functions and configurations as Fig. 2B. For the sake of simplicity, such components will not be described repeatedly.

[0035] The only difference between the optical system in Figure 2B and the optical system in Figure 2C is the angle at which the polarization separation member 101B is disposed relative to the image display surface of the display device 1 and the surface of the retroreflector 2. All other configurations are the same as those of the optical system in Figure 2B, so repeated explanations will be omitted. The polarization design of the optical system in Figure 2C is also the same as that of the optical system in Figure 2B, so repeated explanations will be omitted.

[0036] In the optical system of FIG. 2C , the polarization separator 101B is tilted at an angle α with respect to the image display surface of the display device 1 and the surface of the retroreflector 2. In FIG. 2C , the angle α is 45°. With this configuration, when the polarization separator 101B reflects, the angle β between the direction of propagation of the image light incident from the retroreflector 2 (the direction of the chief ray of the image light) and the direction of propagation of the image light reflected by the polarization separator 101B (the direction of the chief ray of the image light) is 90°. With this configuration, the image display surface of the display device 1 and the surface of the retroreflector 2 are perpendicular to the direction of propagation of the image light reflected by the polarization separator 101B, simplifying the angular relationships of the surfaces that make up the optical system. By arranging the surface of the transparent member 100 so that it is perpendicular to the direction of propagation of the image light reflected by the polarization separator 101B, the angular relationships of the surfaces that make up the optical system can be further simplified. In the configuration of Figure 2C, when a user views the floating image 3 from the direction of arrow A, the floating image 3 is perceived as a bright image. However, when another person views the floating image 3 from the direction of arrow B, the floating image 3 cannot be seen as an image at all. This characteristic is very suitable for use in a system that displays images that require high security or highly confidential images that should be kept secret from people directly facing the user.

[0037] As described above, the optical system of Fig. 2C has a different configuration from the optical systems of Fig. 2A and Fig. 2B, but can form a suitable floating image in space similar to the optical systems of Fig. 2A and Fig. 2B. In addition, the angles of the surfaces constituting the optical system can be made simpler.

[0038] An absorptive polarizer may be provided on the surface of the transparent member 100 facing the polarization separation member 101B. This absorptive polarizer may transmit the polarized waves of the image light from the polarization separation member 101B and absorb the polarized waves that are 90° out of phase with the polarized waves of the image light from the polarization separation member 101B. This allows the image light for forming the space-floating image 3 to be sufficiently transmitted while reducing the external light incident on the space-floating image 3 side of the transparent member 100 by approximately 50%. This allows the stray light in the optical system of FIG. 2C due to the external light incident on the space-floating image 3 side of the transparent member 100 to be reduced.

[0039] According to the optical system of FIGS. 2A, 2B, and 2C described above, it is possible to provide a brighter, higher quality floating image in space.

[0040] <<Block diagram of the internal configuration of the space floating image display device>>

[0041] Next, a description will be given of a block diagram of the internal configuration of the space-floating image display device 1000. Fig. 3 is a block diagram showing an example of the internal configuration of the space-floating image display device 1000.

[0042] The space-floating image display device 1000 includes a retroreflection unit 1101, an image display unit 1102, a light guide 1104, a light source 1105, a power supply 1106, an external power supply input interface 1111, an operation input unit 1107, a nonvolatile memory 1108, a memory 1109, a control unit 1110, a video signal input unit 1131, an audio signal input unit 1133, a communication unit 1132, an aerial operation detection sensor 1351, an aerial operation detection unit 1350, an audio output unit 1140, an image control unit 1160, a storage unit 1170, an imaging unit 1180, etc. In addition, the space-floating image display device 1000 may also include a removable media interface 1134, an attitude sensor 1113, a transmissive self-luminous image display device 1650, a second display device 1680, or a secondary battery 1112.

[0043] Each component of the space floating image display device 1000 is disposed in a housing 1190. The imaging unit 1180 and the mid-air operation detection sensor 1351 shown in FIG.

[0044] The retroreflecting portion 1101 in Fig. 3 corresponds to the retroreflector 2 in Fig. 2A, Fig. 2B, and Fig. 2C. The retroreflecting portion 1101 retroreflects light modulated by the image display portion 1102. Of the light reflected from the retroreflecting portion 1101, the light output to the outside of the space-floating image display device 1000 forms the space-floating image 3.

[0045] 3 corresponds to the liquid crystal display panel 11 in FIGS. 2A, 2B, and 2C. The light source 1105 in FIG. 3 corresponds to the light source device 13 in FIGS. 2A, 2B, and 2C. The image display unit 1102, the light guide 1104, and the light source 1105 in FIG. 3 correspond to the display device 1 in FIGS. 2A, 2B, and 2C.

[0046] The video display unit 1102 is a display unit that generates a video by modulating transmitted light based on a video signal input under the control of a video control unit 1160 (described later). The video display unit 1102 corresponds to the liquid crystal display panel 11 in FIGS. 2A, 2B, and 2C. For example, a transmissive liquid crystal panel is used as the video display unit 1102. Alternatively, for example, a reflective liquid crystal panel that modulates reflected light or a DMD (Digital Micromirror Device: registered trademark) panel may be used as the video display unit 1102.

[0047] The light source 1105 generates light for the image display unit 1102 and is a solid-state light source such as an LED light source or a laser light source. The power source 1106 converts AC current input from the outside via the external power input interface 1111 into DC current and supplies power to the light source 1105. The power source 1106 also supplies the necessary DC current to each unit within the space-floating image display device 1000. The secondary battery 1112 stores the power supplied from the power source 1106. The secondary battery 1112 also supplies power to the light source 1105 and other components that require power via the external power input interface 1111 when power is not supplied from the outside. In other words, when the space-floating image display device 1000 is equipped with the secondary battery 1112, the user can use the space-floating image display device 1000 even when power is not supplied from the outside.

[0048] The light guide 1104 guides light generated by the light source 1105 and irradiates it onto the video display unit 1102. The combination of the light guide 1104 and the light source 1105 can also be called a backlight for the video display unit 1102. The light guide 1104 may be configured mainly using glass. The light guide 1104 may be configured mainly using plastic. The light guide 1104 may be configured using a mirror. There are various possible combinations of the light guide 1104 and the light source 1105. Specific configuration examples of the combination of the light guide 1104 and the light source 1105 will be described in detail later.

[0049] The aerial operation detection sensor 1351 is a sensor that detects an operation on the floating in space image 3 by the finger of the user 230. The aerial operation detection sensor 1351 senses, for example, an area that overlaps with the entire display area of ​​the floating in space image 3. Note that the aerial operation detection sensor 1351 may only sense an area that overlaps with at least a portion of the display area of ​​the floating in space image 3.

[0050] Specific examples of the aerial operation detection sensor 1351 include a distance sensor that uses invisible light such as infrared light, an invisible laser, ultrasonic waves, etc. The aerial operation detection sensor 1351 may also be configured to detect coordinates on a two-dimensional plane by combining multiple sensors. The aerial operation detection sensor 1351 may also be configured with a ToF (Time of Flight) LiDAR (Light Detection and Ranging) or an image sensor.

[0051] The mid-air operation detection sensor 1351 only needs to be capable of sensing to detect touch operations, etc., made by the user with their finger on an object displayed as the floating-in-space image 3. Such sensing can be performed using existing technology.

[0052] The aerial operation detection unit 1350 acquires a sensing signal from the aerial operation detection sensor 1351, and based on the sensing signal, determines whether or not the finger of the user 230 has made contact with an object in the floating in space image 3, and calculates the position (contact position) where the finger of the user 230 has made contact with the object. The aerial operation detection unit 1350 is configured with a circuit such as an FPGA (Field Programmable Gate Array), for example. Furthermore, some of the functions of the aerial operation detection unit 1350 may be realized by software using a spatial operation detection program executed by the control unit 1110, for example.

[0053] The aerial operation detection sensor 1351 and the aerial operation detection unit 1350 may be configured to be built into the space-floating image display device 1000, or may be provided externally as a separate entity from the space-floating image display device 1000. When provided as a separate entity from the space-floating image display device 1000, the aerial operation detection sensor 1351 and the aerial operation detection unit 1350 are configured to be able to transmit information and signals to the space-floating image display device 1000 via a wired or wireless communication connection path or a video signal transmission path.

[0054] Also, the aerial operation detection sensor 1351 and the aerial operation detection unit 1350 may be provided separately. This makes it possible to build a system in which the space-floating image display device 1000 without the aerial operation detection function is used as the main body, and only the aerial operation detection function can be added as an option. Also, a configuration in which only the aerial operation detection sensor 1351 is provided separately, and the aerial operation detection unit 1350 is built into the space-floating image display device 1000 may be used. In cases such as when it is desired to more freely position the aerial operation detection sensor 1351 relative to the installation position of the space-floating image display device 1000, a configuration in which only the aerial operation detection sensor 1351 is provided separately is advantageous.

[0055] The imaging unit 1180 is a camera with an image sensor, and captures images of the space near the floating-in-space image 3 and / or the face, arms, fingers, etc. of the user 230. A plurality of imaging units 1180 may be provided. By using a plurality of imaging units 1180, or by using an imaging unit with a depth sensor, the mid-air operation detection unit 1350 can be assisted in detecting the touch operation of the floating-in-space image 3 by the user 230. The imaging unit 1180 may be provided separately from the floating-in-space image display device 1000. When the imaging unit 1180 is provided separately from the floating-in-space image display device 1000, it is sufficient to configure it so that an imaging signal can be transmitted to the floating-in-space image display device 1000 via a wired or wireless communication connection path or the like.

[0056] For example, if the aerial operation detection sensor 1351 is configured as an object intrusion sensor that targets a plane (intrusion detection plane) including the display surface of the spatial floating image 3 and detects whether or not an object has intruded into this intrusion detection plane, the aerial operation detection sensor 1351 may not be able to detect information such as how far an object (e.g., a user's finger) that has not intruded into the intrusion detection plane is from the intrusion detection plane, or how close the object is to the intrusion detection plane.

[0057] In such a case, the distance between the object and the intrusion detection plane can be calculated by using information such as object depth calculation information based on the captured images of the multiple imaging units 1180 and object depth information from the depth sensor. These pieces of information and various pieces of information such as the distance between the object and the intrusion detection plane are used for various display controls for the floating in space image 3.

[0058] Furthermore, without using the mid-air operation detection sensor 1351, the mid-air operation detection unit 1350 may detect a touch operation on the floating-in-space image 3 by the user 230 based on the captured image by the imaging unit 1180.

[0059] Furthermore, the imaging unit 1180 may capture an image of the face of the user 230 operating the space-floating image 3, and the control unit 1110 may perform an identification process for the user 230. Furthermore, in order to determine whether or not there is another person standing around or behind the user 230 operating the space-floating image 3 and peeking at the operation of the user 230 on the space-floating image 3, the imaging unit 1180 may capture an image of a range including the user 230 operating the space-floating image 3 and the surrounding area of ​​the user 230.

[0060] The operation input unit 1107 is, for example, an operation button, a signal receiving unit such as a remote controller, or an infrared light receiving unit, and inputs a signal for an operation different from the air operation (touch operation) by the user 230. Apart from the above-mentioned user 230 who touches the space floating image 3, the operation input unit 1107 may also be used by, for example, an administrator to operate the space floating image display device 1000.

[0061] The video signal input unit 1131 connects to an external video output device and inputs video data. The video signal input unit 1131 may be configured using various digital video input interfaces. For example, it may be configured using a video input interface conforming to the HDMI (registered trademark) (High-Definition Multimedia Interface) standard, a video input interface conforming to the DVI (Digital Visual Interface) standard, or a video input interface conforming to the DisplayPort standard. Alternatively, an analog video input interface such as analog RGB or composite video may be provided. The audio signal input unit 1133 connects to an external audio output device and inputs audio data. The audio signal input unit 1133 may be configured using an audio input interface conforming to the HDMI standard, an optical digital terminal interface, a coaxial digital terminal interface, or the like. In the case of an HDMI standard interface, the video signal input unit 1131 and the audio signal input unit 1133 may be configured as an interface in which a terminal and a cable are integrated. The audio output unit 1140 is capable of outputting audio based on the audio data input to the audio signal input unit 1133. The audio output unit 1140 may be configured using a speaker. The audio output unit 1140 may also output built-in operation sounds or error warning sounds. Alternatively, the audio output unit 1140 may be configured to output a digital signal to an external device, like the Audio Return Channel function defined in the HDMI standard.

[0062] The nonvolatile memory 1108 stores various data used by the space floating image display device 1000. The data stored in the nonvolatile memory 1108 includes, for example, data for various operations to be displayed on the space floating image 3, display icons, data and layout information for objects to be operated by user operations, etc. The memory 1109 stores image data to be displayed as the space floating image 3, data for controlling the device, etc.

[0063] The control unit 1110 controls the operation of each connected unit. In addition, the control unit 1110 may cooperate with a program stored in the memory 1109 to perform calculations based on information acquired from each unit in the space floating image display device 1000.

[0064] The communication unit 1132 communicates with external devices, external servers, etc. via a wired or wireless communication interface. If the communication unit 1132 has a wired communication interface, the wired communication interface may be configured, for example, as an Ethernet LAN interface. If the communication unit 1132 has a wireless communication interface, the interface may be configured, for example, as a Wi-Fi communication interface, a Bluetooth communication interface, or a mobile communication interface such as 4G or 5G. Various types of data, such as video data, image data, and audio data, are transmitted and received through communication via the communication unit 1132. Furthermore, the removable media interface 1134 is an interface for connecting a removable recording medium (removable media). The removable recording medium (removable media) may be composed of a semiconductor device memory such as a solid state drive (SSD), a magnetic recording medium recording device such as a hard disk drive (HDD), or an optical recording medium such as an optical disk. The removable media interface 1134 can read various information such as video data, image data, and audio data recorded on the removable recording medium. The video data, image data, etc. recorded on the removable recording medium are output as the floating image 3 via the video display unit 1102 and the retroreflection unit 1101.

[0065] The storage unit 1170 is a storage device that records various types of information such as video data, image data, audio data, etc. The storage unit 1170 may be configured with a magnetic recording medium recording device such as a hard disk drive (HDD), or a semiconductor element memory such as a solid state drive (SSD). For example, various types of information such as video data, image data, audio data, etc. may be recorded in advance in the storage unit 1170 at the time of product shipment. Furthermore, the storage unit 1170 may record various types of information such as video data, image data, audio data, etc. acquired from an external device, an external server, etc. via the communication unit 1132.

[0066] The video data, image data, etc. recorded in the storage unit 1170 are output as the space floating image 3 via the video display unit 1102 and the retroreflection unit 1101. The video data, image data, etc. of the display icons and objects for the user to operate, etc., displayed as the space floating image 3, are also recorded in the storage unit 1170.

[0067] Layout information of display icons, objects, etc. displayed as the spatial floating image 3, and various metadata information related to the objects, etc. are also recorded in the storage unit 1170. The audio data recorded in the storage unit 1170 is output as audio from the audio output unit 1140, for example.

[0068] The video control unit 1160 performs various controls related to the video signal input to the video display unit 1102. The video control unit 1160 may be called a video processing circuit, and may be configured with hardware such as an ASIC, FPGA, or video processor. The video control unit 1160 may also be called a video processing unit or an image processing unit. The video control unit 1160 controls video switching, such as which video signal to input to the video display unit 1102, between the video signal to be stored in the memory 1109 and the video signal (video data) input to the video signal input unit 1131, for example.

[0069] In addition, the video control unit 1160 may generate a superimposed video signal by superimposing the video signal to be stored in the memory 1109 and the video signal input from the video signal input unit 1131, and input the superimposed video signal to the video display unit 1102, thereby performing control to form the composite video as the floating-in-space video 3.

[0070] Furthermore, the video control unit 1160 may control image processing of the video signal input from the video signal input unit 1131, the video signal to be stored in the memory 1109, etc. Examples of image processing include scaling processing to enlarge, reduce, deform, etc. the image, brightness adjustment processing to change the brightness, contrast adjustment processing to change the contrast curve of the image, and Retinex processing to decompose the image into light components and change the weighting of each component.

[0071] Furthermore, the video control unit 1160 may perform special effect video processing or the like to assist the aerial operation (touch operation) of the user 230 on the video signal input to the video display unit 1102. The special effect video processing is performed based on, for example, the detection result of the touch operation of the user 230 by the aerial operation detection unit 1350 and the image of the user 230 captured by the imaging unit 1180. The attitude sensor 1113 is a sensor configured by a gravity sensor or an acceleration sensor, or a combination of these, and can detect the attitude in which the space-floating image display device 1000 is installed. Based on the attitude detection result of the attitude sensor 1113, the control unit 1110 may control the operation of each connected unit. For example, when an undesirable attitude in the user's usage state is detected, the control unit 1110 may perform control such that the image being displayed on the image display unit 1102 is stopped and an error message is displayed to the user. Alternatively, when the attitude sensor 1113 detects a change in the installation attitude of the space-floating image display device 1000, the control unit 1110 may perform control such that the display direction of the image being displayed on the image display unit 1102 is rotated.

[0072] As explained above, various functions are installed in the space-floating image display device 1000. However, the space-floating image display device 1000 does not need to have all of these functions, and any configuration is acceptable as long as it has the function of forming the space-floating image 3.

[0073] <Configuration example of a space floating image display device> Next, a configuration example of the space-floating image display device will be explained. The layout of the components of the space-floating image display device according to this embodiment can be various depending on the usage form. Below, the layouts of each of Figs. 4A to 4M will be explained. In addition, in each example of Figs. 4A to 4M, the thick line surrounding the space-floating image display device 1000 indicates an example of the housing structure of the space-floating image display device 1000.

[0074] FIG. 4A is a diagram showing an example of the configuration of a space-floating image display device. The space-floating image display device 1000 shown in FIG. 4A is equipped with an optical system corresponding to the optical system of FIG. 2A. The space-floating image display device 1000 shown in FIG. 4A is installed horizontally so that the surface on which the space-floating image 3 is formed faces upward. That is, in FIG. 4A, the space-floating image display device 1000 has a transparent member 100 installed on the top surface of the device. The space-floating image 3 is formed above the surface of the transparent member 100 of the space-floating image display device 1000. The light of the space-floating image 3 travels diagonally upward. When the mid-air operation detection sensor 1351 is installed as shown in the figure, it can detect the operation of the space-floating image 3 by the finger of the user 230. Note that the x direction is the left-right direction as seen from the user, the y direction is the front-back direction (depth direction) as seen from the user, and the z direction is the up-down direction (vertical direction). Hereinafter, the definitions of the x direction, y direction, and z direction are the same in each drawing of FIG. 4, so repeated explanations will be omitted.

[0075] FIG. 4B is a diagram showing an example of the configuration of a space-floating image display device. The space-floating image display device 1000 shown in FIG. 4B is equipped with an optical system corresponding to the optical system of FIG. 2A. The space-floating image display device 1000 shown in FIG. 4B is installed vertically so that the surface on which the space-floating image 3 is formed faces the front of the space-floating image display device 1000 (toward the user 230). That is, in FIG. 4B, the space-floating image display device is installed with the transparent member 100 facing the front of the device (toward the user 230). The space-floating image 3 is formed on the user 230 side of the surface of the transparent member 100 of the space-floating image display device 1000. The light of the space-floating image 3 travels diagonally upward. If the mid-air operation detection sensor 1351 is provided as shown in the figure, it can detect the operation of the space-floating image 3 by the finger of the user 230. 4B, the mid-air operation detection sensor 1351 can use the reflection of sensing light by the user's nail for touch detection by sensing the finger of the user 230 from above. Generally, the reflectivity of the nail is higher than that of the finger pad, so this configuration can improve the accuracy of touch detection.

[0076] FIG. 4C is a diagram showing an example of the configuration of a space-floating image display device. The space-floating image display device 1000 shown in FIG. 4C is equipped with an optical system corresponding to the optical system of FIG. 2B. The space-floating image display device 1000 shown in FIG. 4C is installed horizontally so that the surface on which the space-floating image 3 is formed faces upward. That is, in FIG. 4C, the space-floating image display device 1000 has a transparent member 100 installed on the top surface of the device. The space-floating image 3 is formed above the surface of the transparent member 100 of the space-floating image display device 1000. The light of the space-floating image 3 travels diagonally upward. If the mid-air operation detection sensor 1351 is provided as shown in the figure, it can detect the operation of the space-floating image 3 by the user's 230 finger.

[0077] FIG. 4D is a diagram showing an example of the configuration of a space-floating image display device. The space-floating image display device 1000 shown in FIG. 4D is equipped with an optical system corresponding to the optical system of FIG. 2B. The space-floating image display device 1000 shown in FIG. 4D is installed vertically so that the surface on which the space-floating image 3 is formed faces the front of the space-floating image display device 1000 (toward the user 230). That is, in FIG. 4D, the space-floating image display device 1000 is installed with the transparent member 100 facing the front of the device (toward the user 230). The space-floating image 3 is formed on the user 230 side of the surface of the transparent member 100 of the space-floating image display device 1000. The light of the space-floating image 3 travels diagonally upward. If the mid-air operation detection sensor 1351 is provided as shown in the figure, it can detect the operation of the space-floating image 3 by the user 230's finger. 4D, the mid-air operation detection sensor 1351 can use the reflection of sensing light by the user's nail for touch detection by sensing the finger of the user 230 from above. Generally, the reflectivity of the nail is higher than that of the finger pad, so this configuration can improve the accuracy of touch detection.

[0078] FIG. 4E is a diagram showing an example of the configuration of a space-floating image display device. The space-floating image display device 1000 shown in FIG. 4E is equipped with an optical system corresponding to the optical system of FIG. 2C. The space-floating image display device 1000 shown in FIG. 4E is installed horizontally so that the surface on which the space-floating image 3 is formed faces upward. That is, in FIG. 4E, the space-floating image display device 1000 has a transparent member 100 installed on the top surface of the device. The space-floating image 3 is formed above the surface of the transparent member 100 of the space-floating image display device 1000. The light of the space-floating image 3 travels directly upward. If the mid-air operation detection sensor 1351 is provided as shown in the figure, it can detect the operation of the space-floating image 3 by the finger of the user 230.

[0079] FIG. 4F is a diagram showing an example of the configuration of a space-floating image display device. The space-floating image display device 1000 shown in FIG. 4F is equipped with an optical system corresponding to the optical system of FIG. 2C. The space-floating image display device 1000 shown in FIG. 4F is installed vertically so that the surface on which the space-floating image 3 is formed faces the front of the space-floating image display device 1000 (toward the user 230). That is, in FIG. 4F, the space-floating image display device 1000 is installed with the transparent member 100 facing the front of the device (toward the user 230). The space-floating image 3 is formed on the user 230 side of the surface of the transparent member 100 of the space-floating image display device 1000. The light of the space-floating image 3 travels toward the user. If the mid-air operation detection sensor 1351 is provided as shown in the figure, it can detect the operation of the space-floating image 3 by the user 230's finger.

[0080] FIG. 4G is a diagram showing an example of the configuration of a space-floating image display device. The space-floating image display device 1000 shown in FIG. 4G is equipped with an optical system corresponding to the optical system shown in FIG. 2C. In the optical systems of the space-floating image display devices shown in FIGS. 4A to 4F, the central optical path of the image light emitted from the display device 1 was on the yz plane. That is, in the optical systems of the space-floating image display devices shown in FIGS. 4A to 4F, the image light traveled in the front-to-back and up-to-down directions as seen from the user. In contrast, in the optical system of the space-floating image display device shown in FIG. 4G, the central optical path of the image light emitted from the display device 1 is on the xy plane. That is, in the optical system of the space-floating image display device shown in FIG. 4G, the image light travels in the left-to-right and front-to-back directions as seen from the user. The space-floating image display device 1000 shown in FIG. 4G is installed so that the surface on which the space-floating image 3 is formed faces the front of the device (toward the user 230). That is, in Fig. 4G, the space-floating image display device 1000 has the transparent member 100 installed on the front side of the device (toward the user 230). The space-floating image 3 is formed on the user side of the surface of the transparent member 100 of the space-floating image display device 1000. The light of the space-floating image 3 travels towards the user. If the mid-air operation detection sensor 1351 is installed as shown in the figure, it can detect the operation of the space-floating image 3 by the finger of the user 230.

[0081] FIG. 4H is a diagram showing an example of the configuration of a space-floating image display device. The space-floating image display device 1000 of FIG. 4H differs from the space-floating image display device of FIG. 4G in that it has a window with a transparent plate 100B made of glass or plastic on the back of the device (opposite the position where the user 230 views the space-floating image 3, i.e., opposite the traveling direction of the image light of the space-floating image 3 toward the user 230). The rest of the configuration is the same as that of the space-floating image display device of FIG. 4G, so repeated explanations will be omitted. The space-floating image display device 1000 of FIG. 4H has a window with a transparent plate 100B on the opposite side of the traveling direction of the image light of the space-floating image 3 from the space-floating image 3. Therefore, when the user 230 views the space-floating image 3, they can recognize the scenery behind the space-floating image display device 1000 as the background of the space-floating image 3. Therefore, the user 230 can perceive the space floating image 3 as floating in the air in front of the scenery behind the space floating image display device 1000. This can further emphasize the floating feeling of the space floating image 3.

[0082] Depending on the polarization distribution of the image light output from the display device 1 and the performance of the polarization separator 101B, a portion of the image light output from the display device 1 may be reflected by the polarization separator 101B and head toward the transparent plate 100B. Depending on the coating performance of the surface of the transparent plate 100B, this light may be reflected again by the surface of the transparent plate 100B and be visible to the user as stray light. Therefore, in order to prevent this stray light, the transparent plate 100B may not be provided in the window on the back of the space-floating image display device 1000.

[0083] FIG. 4I is a diagram showing an example of the configuration of a space-floating image display device. The space-floating image display device 1000 of FIG. 4I differs from the space-floating image display device of FIG. 4H in that a light-blocking door 1410 is provided at the window of a transparent plate 100B located on the back of the device (the opposite side from where the user 230 views the space-floating image 3). Other configurations are the same as those of the space-floating image display device of FIG. 4H , so repeated explanations will be omitted. The door 1410 of the space-floating image display device 1000 of FIG. 4I has, for example, a light-blocking plate and a mechanism for moving (sliding), rotating, or attaching / detaching the light-blocking plate, thereby switching between an open state and a light-blocking state for the window of the transparent plate 100B located at the back of the space-floating image display device 1000 (the rear window). The movement (sliding) and rotation of the light-blocking plate by the door 1410 may be electrically driven by a motor (not shown). The motor may be controlled by the control unit 1110 of FIG. 3. 4I shows an example in which the number of light-shielding plates in the opening and closing door 1410 is two. However, the number of light-shielding plates in the opening and closing door 1410 may be one.

[0084] For example, when the view seen through the window of the transparent plate 100B of the space-floating image display device 1000 is outdoors, the brightness of sunlight varies depending on the weather. When the outdoor sunlight is strong, the background of the space-floating image 3 may become too bright, reducing the user 230's visibility of the space-floating image 3. In such a case, by moving (sliding), rotating, or attaching the light blocking plate of the opening / closing door 1410 to block the light from the rear window, the background of the space-floating image 3 becomes dark, thereby relatively increasing the visibility of the space-floating image 3. Such a blocking operation by the light blocking plate of the opening / closing door 1410 may be performed directly by the force of the user 230's hand. In response to an operation input via the operation input unit 1107 of FIG. 3, the control unit 1110 may control a motor (not shown) to perform the blocking operation by the light blocking plate of the opening / closing door 1410.

[0085] An illuminance sensor may be provided on the rear side (opposite the user 230) of the space-floating image display device 1000, such as near the rear window, to measure the brightness of the space beyond the rear window. In this case, the control unit 1110 of Fig. 3 may control a motor (not shown) to perform the opening and closing operation of the light blocking plate of the opening and closing door 1410 according to the detection result of the illuminance sensor. By controlling the opening and closing operation of the light blocking plate of the opening and closing door 1410 in this way, it becomes possible to more suitably maintain the visibility of the space-floating image 3, even if the user 230 does not manually open and close the light blocking plate of the opening and closing door 1410.

[0086] Furthermore, the light blocking plate by the opening and closing door 1410 may be manually detachable. Depending on the intended use and installation environment of the space floating image display device 1000, the user can select whether to leave the rear window open or in a light blocking state. If it is planned to use the rear window in a light blocking state for a long period of time, the detachable light blocking plate can be fixed in the light blocking state. Also, if it is planned to use the rear window in an open state for a long period of time, it can be used with the detachable light blocking plate removed. The light blocking plate may be attached and detached using screws, a hook structure, or a fitting structure.

[0087] Even in the example of the space-floating image display device 1000 shown in FIG. 4I, depending on the polarization distribution of the image light output from the display device 1 and the performance of the polarization separator 101B, a portion of the image light output from the display device 1 may be reflected by the polarization separator 101B and directed toward the transparent plate 100B. Depending on the coating performance of the surface of the transparent plate 100B, this light may be reflected again by the surface of the transparent plate 100B and be perceived by the user as stray light. Therefore, to prevent this stray light, the window on the back of the space-floating image display device 1000 may be configured without the transparent plate 100B. The above-described opening / closing door 1410 may be provided in a window that does not have the transparent plate 100B. To prevent this stray light, it is desirable that the inner surface of the housing of the light-shielding plate of the above-described opening / closing door 1410 have a coating or material with low light reflectance.

[0088] FIG. 4J is a diagram showing an example of the configuration of a space-floating image display device. The space-floating image display device 1000 of FIG. 4J differs from the space-floating image display device of FIG. 4H in that instead of the transparent plate 100B made of glass or plastic, an electronically controlled transmittance variable device 1620 is provided on the rear window. The other components are the same as those of the space-floating image display device of FIG. 4H, and therefore will not be described again. An example of the electronically controlled transmittance variable device 1620 is a liquid crystal shutter. That is, a liquid crystal shutter can control the transmitted light by controlling the voltage of a liquid crystal element sandwiched between two polarizing plates. Therefore, by controlling the liquid crystal shutter to increase the transmittance, the background of the space-floating image 3 can be seen through the scenery through the rear window. Furthermore, by controlling the liquid crystal shutter to increase the transmittance, the scenery through the rear window can be hidden as the background of the space-floating image 3. Furthermore, since the liquid crystal shutter can be controlled to an intermediate length, it can also be set to a transmittance of 50%, for example. For example, the control unit 1110 may control the transmittance of the electronically controlled transmittance varying device 1620 in response to an operation input via the operation input unit 1107 in Fig. 3. With this configuration, in cases where a viewer wants to see the scenery through the rear window as the background of the Space Floating Image 3, but the scenery through the rear window as the background is too bright and reduces the visibility of the Space Floating Image 3, the visibility of the Space Floating Image 3 can be adjusted by adjusting the transmittance of the electronically controlled transmittance varying device 1620.

[0089] In addition, an illuminance sensor may be provided on the back side (opposite the user 230) of the space-floating image display device 1000, such as near the rear window, to measure the brightness of the space beyond the rear window. In this case, the control unit 1110 in Fig. 3 controls the transmittance of the electronically controlled transmittance variable device 1620 according to the detection result of the illuminance sensor. In this way, even if the user 230 does not perform an operation input via the operation input unit 1107 in Fig. 3, the transmittance of the electronically controlled transmittance variable device 1620 can be adjusted according to the brightness of the space beyond the rear window, making it possible to more suitably maintain the visibility of the space-floating image 3.

[0090] In the above example, a liquid crystal shutter has been described as an example of the electronically controlled variable transmittance device 1620. However, electronic paper may be used as another example of the electronically controlled variable transmittance device 1620. The same effects as those described above can be obtained when electronic paper is used. Furthermore, electronic paper consumes very little power to maintain a halftone state. Therefore, a space floating image display device with lower power consumption can be realized compared to when a liquid crystal shutter is used.

[0091] Fig. 4K is a diagram showing an example of the configuration of a space-floating image display device. The space-floating image display device 1000 of Fig. 4K differs from the space-floating image display device of Fig. 4G in that it has a transmissive self-luminous image display device 1650 instead of the transparent member 100. The other configurations are the same as those of the space-floating image display device of Fig. 4G, so repeated explanations will be omitted.

[0092] In the space-floating image display device 1000 of FIG. 4K, a light beam of an image passes through the display surface of the transmissive self-luminous image display device 1650, and then a space-floating image 3 is formed outside the space-floating image display device 1000. That is, when an image is displayed on the transmissive self-luminous image display device 1650, which is a two-dimensional flat display, the space-floating image 3 can be displayed as a pop-up image further in front of the image displayed on the transmissive self-luminous image display device 1650. In this case, the user 230 can simultaneously view two images at different depth positions. The transmissive self-luminous image display device 1650 may be configured using existing technology such as a transmissive organic EL panel disclosed in, for example, Japanese Patent Application Laid-Open No. 2014-216761. Although not shown in FIG. 3, the transmissive self-luminous image display device 1650 may be configured as a component of the space-floating image display device 1000 of FIG. 3 and connected to other processing units such as the control unit 1110.

[0093] Here, if the transmissive self-luminous video display device 1650 displays both the background and an object such as a character, and then the object such as the character moves to the foreground, the floating video image 3, a more effective surprise video experience can be provided to the user 230.

[0094] Furthermore, if the inside of the space-floating image display device 1000 is kept in a light-blocking state, the background of the transmissive self-luminous image display device 1650 becomes sufficiently dark. Therefore, when no image is displayed on the display device 1 or the light source of the display device 1 is turned off and an image is displayed only on the transmissive self-luminous image display device 1650, the transmissive self-luminous image display device 1650 appears to the user 230 as a normal two-dimensional flat display rather than a transmissive display (since the space-floating image 3 in the embodiment of the present invention is displayed as a real optical image in a space without a screen, if the light source of the display device 1 is turned off, the intended display position of the space-floating image 3 becomes empty space). Therefore, when the transmissive self-luminous image display device 1650 is used to display an image as if it were a normal two-dimensional flat display, characters, objects, etc. can be suddenly displayed in the air as the space-floating image 3, thereby providing the user 230 with a more effective surprise video experience.

[0095] Note that the darker the interior of the space-floating image display device 1000, the more the transmissive self-luminous image display device 1650 appears like a two-dimensional flat display. Therefore, an absorptive polarizer (not shown) that transmits the polarized waves of the image light reflected by the polarization separation member 101B and absorbs polarized waves that are 90° out of phase with the polarized waves may be provided on the surface of the transmissive self-luminous image display device 1650 facing the interior of the space-floating image display device 1000 (the surface where the image light reflected by the polarization separation member 101B enters the transmissive self-luminous image display device 1650, i.e., the surface of the transmissive self-luminous image display device 1650 opposite the space-floating image 3). This does not have a significant effect on the image light that forms the space-floating image 3, but it can significantly reduce the light that enters the interior of the space-floating image display device 1000 from the outside through the transmissive self-luminous image display device 1650, making the interior of the space-floating image display device 1000 darker, which is preferable.

[0096] 4L is a diagram showing an example of the configuration of a space-floating image display device. The space-floating image display device 1000 of FIG. 4L is a modified example of the space-floating image display device of FIG. 4K. The orientation of the components in the space-floating image display device 1000 is different from that of the space-floating image display device of FIG. 4K, and is closer to the arrangement of the space-floating image display device of FIG. 4F. The functions and operations of each component are the same as those of the space-floating image display device of FIG. 4K, so repeated explanations will be omitted.

[0097] In the space-floating image display device of FIG. 4L, after the luminous flux of image light passes through the transmissive self-luminous image display device 1650, a space-floating image 3 is formed on the user 230 side of the transmissive self-luminous image display device 1650.

[0098] In both the example of the space-floating image display device of FIG. 4K and the example of the space-floating image display device of FIG. 4L, the space-floating image 3 is displayed superimposed on the image of the transmissive self-luminous image display device 1650 as seen by the user 230. Here, the position of the space-floating image 3 and the position of the image of the transmissive self-luminous image display device 1650 are configured to have a difference in the depth direction. Therefore, when the user moves their head (the position of the viewpoint), they can recognize the depth of the two images due to parallax. Therefore, by displaying two images at different depth positions, it is possible to provide the user with a more suitable three-dimensional image experience with the naked eye without the need for stereoscopic glasses or the like.

[0099] Fig. 4M is a diagram showing an example of the configuration of a space-floating image display device. The space-floating image display device 1000 of Fig. 4M is provided with a second display device 1680 on the rear side as seen from the user relative to the polarization separation member 101B of the space-floating image display device of Fig. 4G. The other configurations are the same as those of the space-floating image display device of Fig. 4G, so repeated explanations will be omitted.

[0100] In the configuration example shown in FIG. 4M, the second display device 1680 is provided behind the display position of the space-floating image 3, and its image display surface faces the space-floating image 3. With this configuration, from the user 230's perspective, the image of the second display device 1680 and the space-floating image 3, which are displayed at two different depth positions, can be viewed superimposed on each other. In other words, the second display device 1680 is positioned so as to display an image in the direction of the user 230 viewing the space-floating image 3. Although the second display device 1680 is not shown in FIG. 3, it may be configured to be connected to other processing units such as the control unit 1110 as one component of the space-floating image display device 1000 of FIG. 3.

[0101] Note that the image light of the second display device 1680 of the space-floating image display device 1000 of FIG. 4M is viewed by the user 230 after passing through the polarization separator 101B. Therefore, in order for the image light of the second display device 1680 to more suitably pass through the polarization separator 101B, it is desirable that the image light output from the second display device 1680 be polarized in a vibration direction that the polarization separator 101B more suitably transmits. That is, it is desirable that the image light be polarized in the same vibration direction as the polarization of the image light output from the display device 1. For example, if the image light output from the display device 1 is S-polarized, it is desirable that the image light output from the second display device 1680 is also S-polarized. Furthermore, if the image light output from the display device 1 is P-polarized, it is desirable that the image light output from the second display device 1680 is also P-polarized.

[0102] The example of the space-floating image display device of FIG. 4M also has the same effect as the example of the space-floating image display device of FIG. 4K and the example of the space-floating image display device of FIG. 4L in that a second image is displayed behind the space-floating image 3. However, unlike the example of the space-floating image display device of FIG. 4K and the example of the space-floating image display device of FIG. 4L, in the example of the space-floating image display device of FIG. 4M, the luminous flux of image light for forming the space-floating image 3 does not pass through the second display device 1680. Therefore, the second display device 1680 does not need to be a transmissive self-luminous image display device, but may be a liquid crystal display, which is a two-dimensional flat display. The second display device 1680 may also be an organic EL display. Therefore, the example of the space-floating image display device of FIG. 4M can realize the space-floating image display device 1000 at a lower cost than the example of the space-floating image display device of FIG. 4K and the example of the space-floating image display device of FIG. 4L.

[0103] Here, depending on the polarization distribution of the image light output from the display device 1 and the performance of the polarization separation member 101B, a portion of the image light output from the display device 1 may be reflected by the polarization separation member 101B and travel toward the second display device 1680. This light (a portion of the image light) may be reflected again by the surface of the second display device 1680 and may be visually recognized by the user as stray light.

[0104] Therefore, to prevent this stray light, an absorptive polarizer may be provided on the surface of the second display device 1680. In this case, the absorptive polarizer may be an absorptive polarizer that transmits the polarized waves of the image light output from the second display device 1680 and absorbs polarized waves that are 90° out of phase with the polarized waves of the image light output from the second display device 1680. If the second display device 1680 is a liquid crystal display, an absorptive polarizer is also provided on the image output side of the liquid crystal display. However, if there is a cover glass (cover glass on the image display surface side) on the output surface of the absorptive polarizer on the image output side of the liquid crystal display, it is not possible to prevent stray light caused by reflection of the cover glass by light from outside the liquid crystal display. Therefore, it is necessary to separately provide the above-mentioned absorptive polarizer on the surface of the cover glass.

[0105] When an image is displayed on the second display device 1680, which is a two-dimensional flat display, the floating-in-space image 3 can be displayed as an image further in front of the image on the second display device 1680. In this case, the user 230 can simultaneously view two images at different depth positions. By displaying a character on the floating-in-space image 3 and a background on the second display device 1680, it is possible to provide the effect that the user 230 is viewing the space in which the character exists in a three-dimensional manner.

[0106] Furthermore, if the second display device 1680 displays both the background and an object such as a character, and then the object such as the character moves to the foreground in the floating image 3, it is possible to provide the user 230 with a more effective surprise visual experience.

[0107] <Display device> Next, the display device 1 of this embodiment will be described with reference to the drawings. The display device 1 of this embodiment includes an image display element 11 (liquid crystal display panel) and a light source device 13 that constitutes its light source. In Fig. 5, the light source device 13 is shown together with the liquid crystal display panel as an exploded perspective view.

[0108] As shown by arrow 30 in Figure 5, this liquid crystal display panel (image display element 11) receives an illumination light beam from light source device 13, which is a backlight device, that has narrow-angle diffusion characteristics, i.e., has strong directivity (straightness) and characteristics similar to laser light with a polarization plane aligned in one direction. The liquid crystal display panel (image display element 11) modulates the received illumination light beam in accordance with an input video signal. The modulated image light is reflected by retroreflector 2 and passes through transparent member 100 to form a real image, a floating image in space (see Figure 1).

[0109] 5 also shows a configuration including a liquid crystal display panel 11 constituting the display device 1, a light redirection panel 54 that controls the directional characteristics of the light beam emitted from the light source device 13, and a narrow-angle diffuser (not shown) as needed. Specifically, polarizing plates are provided on both sides of the liquid crystal display panel 11, and image light of a specific polarization is emitted with its intensity modulated by a video signal (see arrow 30 in FIG. 5). This allows a desired image to be projected as highly directional (linearly propagating) light of a specific polarization via the light redirection panel 54 toward the retroreflector 2. After being reflected by the retroreflector 2, the light is transmitted toward the eyes of an observer outside the store (space), forming a floating image 3. A protective cover 50 (see FIGS. 6 and 7) may be provided on the surface of the light redirection panel 54.

[0110] <Display device example 1> FIG. 6 shows an example of a specific configuration of the display device 1. In FIG. 6, a liquid crystal display panel 11 and a light direction conversion panel 54 are disposed on the light source device 13 shown in FIG. 5. The light source device 13 is configured on a case shown in FIG. 5, which is formed of, for example, plastic and contains LED elements 201 and a light guide 203. As shown in FIG. 5 and other figures, the end surface of the light guide 203 is provided with a lens shape whose cross-sectional area gradually increases toward the light receiving section in order to convert the divergent light from each LED element 201 into a substantially parallel beam. The lens shape has an effect of gradually reducing the divergence angle by multiple total reflections during propagation inside. The liquid crystal display panel 11 constituting the display device 1 is attached to the top surface of the display device 1. In addition, LED (Light Emitting Diode) elements 201, which are semiconductor light sources, and an LED board 202 on which their control circuits are mounted are attached to one side surface of the case of the light source device 13 (the left end surface in this example). A heat sink, which is a member for cooling the heat generated by the LED elements and the control circuit, may be attached to the outer surface of the LED substrate 202.

[0111] The liquid crystal display panel frame (not shown) is attached to the top surface of the case of the light source device 13. The liquid crystal display panel 11 is attached to the frame, and an FPC (Flexible Printed Circuits) (not shown) electrically connected to the liquid crystal display panel 11 is also attached to the frame. That is, the liquid crystal display panel 11, which is the image display element, generates a display image by modulating the intensity of transmitted light in conjunction with the LED elements 201, which are solid-state light sources, based on a control signal from a control circuit (image control unit 1160 in FIG. 3) constituting the electronic device. The generated image light has a narrow diffusion angle and contains only specific polarization components, resulting in a novel image display device similar to a surface-emitting laser image source driven by a video signal. Currently, it is technically and safety-wise impossible to obtain a laser beam of the same size as the image obtained by the display device 1 described above using a laser device. Therefore, in this embodiment, light similar to the surface-emitting laser image light described above is obtained from a beam of light from a general light source, such as an LED element.

[0112] Next, the configuration of the optical system housed in the case of the light source device 13 will be described in detail with reference to FIG. 7 as well as FIG.

[0113] 6 and 7 are cross-sectional views, and only one of the multiple LED elements 201 constituting the light source is shown, and this is converted into approximately collimated light by the shape of the light-receiving end surface 203a of the light guide 203. For this reason, the light-receiving section on the end surface of the light guide and the LED element are attached while maintaining a predetermined positional relationship.

[0114] Each light guide 203 is formed of a translucent resin such as acrylic. The LED light receiving surface at the end of light guide 203 has a cone-shaped outer periphery obtained by rotating a parabolic cross section, and at the top of the light guide 203, a concave portion with a convex portion (i.e., a convex lens surface) formed in the center is formed, and at the center of the flat portion, a convex lens surface (or a concave lens surface) that protrudes outward (not shown). The outer shape of the light receiving portion of the light guide to which LED element 201 is attached is a parabolic shape that forms a cone-shaped outer periphery, and is set within an angle range that allows total reflection within the light that is emitted from the LED element toward the periphery, or a reflective surface is formed.

[0115] On the other hand, the LED elements 201 are arranged at predetermined positions on the surface of the circuit board, that is, the LED substrate 202. The LED substrate 202 is arranged and fixed to the LED collimator (light-receiving end surface 203a) so that the LED elements 201 on the surface are positioned in the center of the recessed portion described above.

[0116] According to this configuration, the shape of the light-receiving end surface 203a of the light guide 203 makes it possible to extract the light emitted from the LED element 201 as approximately parallel light, thereby improving the efficiency of use of the generated light.

[0117] As described above, the light source device 13 is configured by attaching a light source unit in which a plurality of LED elements 201 serving as light sources are arranged to the light-receiving end surface 203a, which is a light-receiving section provided on the end surface of the light guide 203, and the divergent light beams from the LED elements 201 are converted into approximately parallel light by the lens shape of the light-receiving end surface 203a of the light guide end surface, which is then guided inside the light guide 203 (in a direction parallel to the drawing) as shown by the arrow, and emitted by the light beam direction conversion means 204 toward the liquid crystal display panel 11, which is disposed approximately parallel to the light guide 203 (in a direction perpendicular to the front of the drawing). The uniformity of the light beam incident on the liquid crystal display panel 11 can be controlled by optimizing the distribution (density) of the light beam direction conversion means 204 depending on the shape inside or on the surface of the light guide.

[0118] The light beam direction conversion means 204 described above emits the light beam propagated inside the light guide toward the liquid crystal display panel 11 (in a direction perpendicular to the front of the drawing) which is disposed substantially parallel to the light guide 203, by changing the shape of the surface of the light guide or by providing a portion with a different refractive index inside the light guide. In this case, when the liquid crystal display panel 11 is faced directly at the center of the screen and the viewpoint is positioned at the same position as the diagonal dimension of the screen, if the relative brightness ratio between the center of the screen and the periphery of the screen is 20% or more, there is no practical problem, and if it exceeds 30%, it will be an even better characteristic.

[0119] 6 is a cross-sectional layout diagram illustrating the configuration and operation of a light source of this embodiment that performs polarization conversion in light source device 13 including light guide 203 and LED element 201. In Fig. 6, light source device 13 is composed of light guide 203 formed of, for example, plastic or the like and having light beam direction conversion means 204 on its surface or inside, LED element 201 as a light source, reflective sheet 205, retardation plate 206, lenticular lens, etc., and on the upper surface of light source device 13 is attached liquid crystal display panel 11 that has polarizing plates on the light source light entrance surface and the image light exit surface.

[0120] In addition, a film- or sheet-like reflective polarizing plate 49 is provided on the light source light incident surface (bottom surface in the figure) of the liquid crystal display panel 11 corresponding to the light source device 13, selectively reflecting one polarization (e.g., P-wave) 212 of the natural light beam 210 emitted from the LED element 201. The reflected light is reflected again by a reflective sheet 205 provided on one surface (bottom surface in the figure) of the light guide 203 and directed toward the liquid crystal display panel 11. Therefore, a retardation plate (λ / 4 plate) is provided between the reflective sheet 205 and the light guide 203 or between the light guide 203 and the reflective polarizing plate 49. The reflected light beam is reflected by the reflective sheet 205 and passes through it twice, converting the reflected light beam from P-polarized to S-polarized, thereby improving the utilization efficiency of the light source light as image light. The image light beam, the light intensity of which is modulated by a video signal in the liquid crystal display panel 11 (arrow 213 in Figure 6), enters the retroreflector 2. After reflection by the retroreflector 2, a real, floating image can be obtained.

[0121] 7 is a cross-sectional layout diagram illustrating the configuration and operation of a light source of this embodiment that performs polarization conversion in light source device 13 including light guide 203 and LED elements 201, similar to Fig. 6. Light source device 13 is similarly composed of light guide 203 formed of, for example, plastic and having light beam direction conversion means 204 on its surface or inside, LED elements 201 as a light source, reflective sheet 205, retardation plate 206, lenticular lens, etc. On the top surface of light source device 13, a liquid crystal display panel 11 is attached as an image display element, which has polarizing plates on the light source light entrance surface and the image light exit surface.

[0122] A film or sheet-like reflective polarizing plate 49 is provided on the light source light incident surface (bottom surface in the figure) of the liquid crystal display panel 11 corresponding to the light source device 13, selectively reflecting one polarized wave (e.g., S wave) 211 of the natural light beam 210 emitted from the LED element 201. In other words, the selective reflection characteristics of the reflective polarizing plate 49 in the example of FIG. 7 differ from those in FIG. 7. The reflected light is reflected by a reflective sheet 205 provided on one surface (bottom surface in the figure) of the light guide 203 and returns to the liquid crystal display panel 11. A retardation plate (λ / 4 plate) is provided between the reflective sheet 205 and the light guide 203 or between the light guide 203 and the reflective polarizing plate 49, and the reflected light beam is reflected by the reflective sheet 205 and passes through it twice, converting it from S-polarized light to P-polarized light, thereby improving the utilization efficiency of the light source light as image light. The image light beam intensity-modulated by the image signal in the liquid crystal display panel 11 (arrow 214 in FIG. 7) enters the retroreflector 2. After reflection by the retroreflector 2, a real image, a floating image in space, can be obtained.

[0123] In the light source devices shown in Figures 6 and 7, in addition to the function of the polarizer provided on the light incident surface of the corresponding liquid crystal display panel 11, the reflective polarizer reflects the polarized light component on one side, so the theoretically obtainable contrast ratio is the reciprocal of the cross transmittance of the reflective polarizer multiplied by the reciprocal of the cross transmittance obtained by the two polarizers attached to the liquid crystal display panel. This results in high contrast performance. In fact, experiments have confirmed that the contrast performance of the displayed image is improved by more than 10 times. As a result, high-quality images comparable to those of self-luminous organic EL displays are obtained.

[0124] <Display device example 2> 8 shows another example of the specific configuration of the display device 1. 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 103, 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.

[0125] 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) 403 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.

[0126] <Display device example 3> Next, another example of the specific configuration of the display device 1 (Example 3 of the display device) will be described with reference to Fig. 9. The light source device of this display device 1 converts a divergent beam of light (a mixture of P-polarized and S-polarized light) from an LED into a substantially parallel beam by a collimator 18, and reflects the parallel beam toward the liquid crystal display panel 11 by the reflecting surface of a reflective light guide 304. The reflected light is incident on a reflective polarizer 49 disposed between the liquid crystal display panel 11 and the reflective light guide 304. The reflective polarizer 49 transmits light of a specific polarization (e.g., P-polarized light) and causes the transmitted polarized light to be incident on the liquid crystal display panel 11. Here, light of polarization other than the specific polarization (e.g., S-polarized light) is reflected by the reflective polarizer 49 and directed toward the reflective light guide 304 again.

[0127] The reflective polarizing plate 49 is installed at an angle with respect to the liquid crystal display panel 11 so that the reflective polarizing plate 49 is not perpendicular to the chief ray of light from the reflective surface of the reflective light guide 304. The chief ray of the light reflected by the reflective polarizing plate 49 is incident on the transmission surface of the reflective light guide 304. The light that has entered the transmission surface of the reflective light guide 304 passes through the back surface of the reflective light guide 304, passes through the λ / 4 plate 270 which is a retardation plate, and is reflected by the reflector 271. The light reflected by the reflector 271 passes through the λ / 4 plate 270 again, and passes through the transmission surface of the reflective light guide 304. The light that has passed through the transmission surface of the reflective light guide 304 is incident on the reflective polarizing plate 49 again.

[0128] At this time, the light that re-enters the reflective polarizer 49 has passed through the λ / 4 plate 270 twice, and therefore its polarization has been converted to a polarization (for example, P-polarized light) that is transmitted through the reflective polarizer 49. Therefore, the light whose polarization has been converted passes through the reflective polarizer 49 and enters the liquid crystal display panel 11. Note that with regard to the polarization design related to the polarization conversion, the polarization may be configured in reverse from the above explanation (S-polarized light and P-polarized light may be reversed).

[0129] As a result, the light from the LED is aligned to a specific polarization (for example, P polarization), enters the liquid crystal display panel 11, and is brightness-modulated in accordance with the video signal to display an image on the panel surface. As in the above example, multiple LEDs that make up the light source are shown (however, since this is a vertical cross section, only one is shown in Figure 9), and these are attached at predetermined positions relative to the collimator 18.

[0130] Each of the collimators 18 is formed of, for example, a translucent resin such as acrylic or glass. The collimator 18 may have a cone-shaped outer peripheral surface obtained by rotating a parabolic cross section. The collimator 18 may have a concave portion with a convex portion (i.e., a convex lens surface) formed in the center of the apex (the side facing the LED substrate 102). The collimator 18 may have a convex lens surface (or a concave lens surface) protruding outward in the center of the flat portion (the side opposite the apex). The parabolic surface forming the cone-shaped outer peripheral surface of the collimator 18 is set within an angle range that allows total reflection of the light emitted from the LED toward the periphery within the parabolic surface, or a reflective surface is formed therein.

[0131] The LEDs are arranged at predetermined positions on the surface of the circuit board, that is, the LED substrate 102. The LED substrate 102 is arranged and fixed to the collimator 18 so that the LEDs on the surface are positioned at the center of the apex of the convex cone shape (or in the recess if there is a recess at the apex).

[0132] With this configuration, the collimator 18 focuses the light emitted from the LED, particularly the light emitted from the central portion, into parallel light by the convex lens surface that forms the outer shape of the collimator 18. 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 18, and is similarly focused into parallel light. In other words, the collimator 18, 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 as parallel light, thereby improving the utilization efficiency of the generated light.

[0133] Furthermore, the light converted into approximately parallel light by the collimator 18 shown in FIG. 9 is reflected by the reflective light guide 304. Due to the action of the reflective polarizer 49, light of a specific polarization of the light is transmitted through the reflective polarizer 49, while light of the other polarization reflected by the reflective polarizer 49 is transmitted again through the light guide 304. The light is reflected by the reflector 271, which is located opposite the liquid crystal display panel 11 with respect to the reflective light guide 304. At this time, the light is polarized and converted twice by passing through the λ / 4 plate 270, which is a retardation plate. The light reflected by the reflector 271 is transmitted again through the light guide 304 and enters the reflective polarizer 49 provided on the opposite surface. Since the incident light has been polarization-converted, it passes through the reflective polarizer 49, aligns its polarization direction, and enters the liquid crystal display panel 11. As a result, all of the light from the light source can be utilized, thereby doubling the geometrical optical utilization efficiency of light. Furthermore, since the degree of polarization (extinction ratio) of the reflective polarizer is also included in the extinction ratio of the entire system, the use of the light source device of this embodiment significantly improves the contrast ratio of the entire display device. Adjusting the surface roughness of the reflective surface of the reflective light guide 304 and the surface roughness of the reflector 271 allows adjustment of the angle of light reflection and diffusion at each reflective surface. The surface roughness of the reflective surface of the reflective light guide 304 and the surface roughness of the reflector 271 can be adjusted for each design to optimize the uniformity of the light incident on the liquid crystal display panel 11.

[0134] It should be noted that the λ / 4 plate 270, which is the retardation plate in Fig. 9, does not necessarily have to have a phase difference of λ / 4 with respect to polarized light that is perpendicularly incident on the λ / 4 plate 270. In the configuration of Fig. 9, any retardation plate may be used as long as the phase changes by 90° (λ / 2) when polarized light passes through it twice. The thickness of the retardation plate may be adjusted according to the incident angle distribution of the polarized light.

[0135] <Display device example 4> Furthermore, another example (Example 4 of Display Device) of the configuration of an optical system such as a light source device of a display device will be described with reference to Fig. 10. This is an example of a configuration in which a diffusion sheet is used instead of reflective light guide 304 in the light source device of Example 3 of the display device. Specifically, two optical sheets (optical sheet 207A and optical sheet 207B) that convert the diffusion characteristics in the vertical and horizontal directions of the drawing (front-to-back directions not shown in the drawing) are used on the light emission side of collimator 18, and light from collimator 18 is made to enter between the two optical sheets (diffusion sheets).

[0136] The optical sheet may be a single sheet instead of a two-sheet configuration. In the case of a single sheet configuration, the vertical and horizontal diffusion characteristics are adjusted by the fine shapes on the front and back surfaces of the single optical sheet. Alternatively, multiple diffusion sheets may be used to share the functions. In the example of FIG. 10, the reflection and diffusion characteristics due to the front and back shapes of optical sheets 207A and 207B can be optimally designed using the number of LEDs, the divergence angle from LED substrate (optical element) 102, and the optical specifications of collimator 18 as design parameters so that the surface density of the light beam emitted from liquid crystal display panel 11 is uniform. In other words, the diffusion characteristics are adjusted by the surface shapes of multiple diffusion sheets instead of light guides.

[0137] In the example of FIG. 10, polarization conversion is performed in the same manner as in the display device example 3 described above. That is, in the example of FIG. 10, reflective polarizing plate 49 may be configured to have the property of reflecting S-polarized light (transmitting P-polarized light). In this case, the reflective polarizing plate 49 transmits P-polarized light out of the light emitted from the LED light source, and the transmitted light enters liquid crystal display panel 11. The reflective polarizing plate 49 reflects S-polarized light out of the light emitted from the LED light source, and the reflected light passes through retardation plate 270 shown in FIG. 10. The light that passes through retardation plate 270 is reflected by reflector 271. The light reflected by reflector 271 passes through retardation plate 270 again and is converted to P-polarized light. The polarization-converted light passes through reflective polarizing plate 49 and enters liquid crystal display panel 11.

[0138] It should be noted that the λ / 4 plate 270, which is the retarder in FIG. 10, does not necessarily have to have a phase difference of λ / 4 with respect to polarized light that is perpendicularly incident on the λ / 4 plate 270. In the configuration of FIG. 10, any retarder that changes the phase by 90° (λ / 2) when polarized light passes through it twice will suffice. The thickness of the retarder may be adjusted according to the distribution of incident angles of the polarized light. It should be noted that in FIG. 10 as well, the polarization design for polarization conversion may be configured in reverse (reversing the S-polarized light and P-polarized light) from the above explanation.

[0139] In a typical TV device, the light emitted from the LCD panel 11 has similar diffusion characteristics in both the horizontal direction of the screen (shown on the X-axis in FIG. 12(a)) and the vertical direction of the screen (shown on the Y-axis in FIG. 12(b)). In contrast, the diffusion characteristics of the light beam emitted from the LCD panel of this embodiment are 1 / 5 of the 62-degree viewing angle of a typical TV device, as shown in Example 1 of FIG. 12, when the viewing angle at which the luminance is 50% of that at a front view (angle of 0 degrees) is set to 13 degrees. Similarly, the vertical viewing angle is asymmetric between the top and bottom, and the reflection angle and the area of ​​the reflective surface of the reflective light guide are optimized to keep the upper viewing angle to about 1 / 3 of the lower viewing angle. As a result, the amount of image light directed toward the monitoring direction is significantly improved compared to conventional LCD TVs, with brightness more than 50 times higher.

[0140] Furthermore, assuming the viewing angle characteristics shown in Example 2 in Figure 12, if the viewing angle at which brightness is 50% of that when viewed from the front (angle of 0 degrees) is set to 5 degrees, this will be 1 / 12 of the 62 degrees of devices used for general TV applications. Similarly, the vertical viewing angle is optimized by optimizing the reflection angle and the area of ​​the reflective surface of the reflective light guide so that the viewing angle is approximately 1 / 12 of that of devices used for general TV applications, with equal viewing angle both above and below. As a result, the amount of image light directed in the monitoring direction is significantly improved compared to conventional LCD TVs, and brightness is more than 100 times greater.

[0141] As described above, by setting the viewing angle to a narrow angle, the amount of luminous flux directed in the monitoring direction can be concentrated, significantly improving the efficiency of light utilization. As a result, even when using a liquid crystal display panel for general TV applications, by controlling 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 compatible with information display systems facing bright outdoor environments.

[0142] When using a large LCD display panel, the overall 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 observer when the observer is facing the center of the screen. Figure 11 shows the convergence angle between the long and short sides of the panel when the observer's distance from the panel, L, and the panel size (screen ratio 16:10) are used as parameters. When monitoring with the screen in portrait orientation, the convergence angle can be set to match the short side. For example, when using a 22" panel in portrait orientation and the monitoring distance is 0.8m, a convergence angle of 10 degrees will allow the image light from the four corners of the screen to be effectively directed toward the observer.

[0143] Similarly, when monitoring with a 15" panel in portrait orientation and the monitoring distance is 0.8 m, a convergence angle of 7 degrees will allow the image light from the four corners of the screen to be effectively directed towards the monitor. As described above, depending on the size of the LCD panel and whether it is used portrait or landscape, the overall brightness of the screen can be improved by directing the image light from the periphery of the screen towards the monitor who is in the optimum position to monitor the centre of the screen.

[0144] As shown in Figure 9, the basic configuration involves a light source device directing a light beam with a narrow angle of directionality to a liquid crystal display panel 11, which is then luminance-modulated according to a video signal. The video information displayed on the screen of the liquid crystal display panel 11 is then reflected by a retroreflector, and the resulting floating image is displayed indoors or outdoors via a transparent member 100.

[0145] By using the display device and light source device according to the embodiment of the present invention described above, it is possible to realize a space floating image display device with higher light utilization efficiency.

[0146] <Example of image display processing in a space floating image display device> Next, an example of a problem solved by the image processing of this embodiment will be described with reference to Fig. 13A. In the space-floating image display device 1000, when the far side of the space-floating image 3 from the user's perspective is inside the housing of the space-floating image display device 1000 and it is sufficiently dark, the user will visually recognize that the background of the space-floating image 3 is black.

[0147] Here, an example of displaying a character "panda" 1525 in the space floating image 3 will be described using Fig. 13A. First, the image control unit 1160 in Fig. 3 distinguishes and recognizes the pixel area where the image of the character "panda" 1525 is drawn from the transparent information area 1520 which is the background image, for an image including the pixel area where the image of the character "panda" 1525 is drawn and the transparent information area 1520 which is the background image, as shown in Fig. 13A(1).

[0148] A method for distinguishing and recognizing the character image from the background image is, for example, to configure the image processing of the video control unit 1160 so that the background image layer and the character image layer in front of the background image layer can be processed as separate layers, and the character image and background image can be distinguished and recognized based on the superimposition relationship when these layers are combined.

[0149] Here, the image control unit 1160 recognizes black pixels that depict objects such as character images and transparent information pixels as different information. However, it is assumed that both the black pixels that depict objects and the transparent information pixels have a luminance of 0. In this case, when the space floating image 3 is displayed, there is no difference in luminance between the pixels that depict black in the image of the character "panda" 1525 and the pixels of the transparent information region 1520, which is the background image. Therefore, in the space floating image 3, as shown in FIG. 13A(2), neither the pixels that depict black in the image of the character "panda" 1525 nor the pixels of the transparent information region 1520 have luminance, and they are visually perceived by the user as the same optically black space. In other words, the black parts of the image of the character "panda" 1525, which is an object, blend into the background, and only the non-black parts of the character "panda" 1525 are perceived as floating in the display region of the space floating image 3.

[0150] An example of image processing according to this embodiment will be described with reference to FIG. 13B. FIG. 13B is a diagram illustrating an example of image processing that more suitably resolves the issue of the black image region of the object blending into the background, as described in FIG. 13A. In FIGS. 13B(1) and 13B(2), the upper side shows the display state of the floating image 3 in space, and the lower side shows the input / output characteristics of the image processing of the image of the object. Note that the image of the object (character "panda" 1525) and the corresponding data may be read from the storage unit 1170 or memory 1109 in FIG. 3, or may be input from the video signal input unit 1131, or may be acquired via the communication unit 1132.

[0151] In the state shown in Figure 13B(1), the input / output characteristics of the image processing of the object image are in a linear state with no particular adjustment. In this case, the display state is the same as that shown in Figure 13A(2), and the black image area of ​​the object blends into the background. In contrast, in Figure 13B(2), the video control unit 1160 of this embodiment adjusts the input / output characteristics of the image processing of the image of the object (character "panda" 1525) to the input / output characteristics shown in the lower part.

[0152] That is, the video control unit 1160 performs image processing with input / output characteristics on the image of the object (character "panda" 1525), which has a characteristic of converting pixels in low-brightness areas of the input image into output pixels with increased brightness values. After the image of the object (character "panda" 1525) has been subjected to image processing with the input / output characteristics, a video including the image of the object (character "panda" 1525) is input to the display device 1 and displayed. Then, as shown in the upper part of FIG. 13B(2), the display state of the floating in space image 3 is such that the brightness of pixel areas depicting black in the image of character "panda" 1525 increases. This allows the user to distinguish the areas depicting black among the areas depicting the image of character "panda" 1525 without them blending into the black background, making it possible to display the object more appropriately.

[0153] 13B(2), the area displaying the image of the character "panda" 1525, which is an object, can be distinguished from the black background inside the housing of the space-floating image display device 1000 through the window, improving the visibility of the object. Therefore, for example, even if the object includes pixels with a brightness value of 0 before the image processing (i.e., when the image of the object or the corresponding data is read from the storage unit 1170 or memory 1109 in FIG. 3, or when the image of the object is input from the video signal input unit 1131, or when the data of the object is obtained via the communication unit 1132, etc.), the image processing of the input / output characteristics by the video control unit 1160 converts the object into an object with a brightness value of 0 increased for the pixels in the low-brightness area, and then the object is displayed on the display device 1 and converted into a space-floating image 3 by the optical system of the space-floating image display device 1000.

[0154] That is, the pixels that make up the object after image processing of the input / output characteristics are converted to a state in which they do not include pixels with a brightness value of 0, and then they are displayed on the display device 1 and converted into a floating image 3 in space by the optical system of the floating image display device 1000.

[0155] In the image processing of Figure 13B(2), a method for applying image processing with the input / output characteristics of Figure 13B(2) only to the image area of ​​the object (character "panda" 1525) is, for example, to configure the image processing of the video control unit 1160 so that the background image layer and the layer of the character image in front of the background image layer can be processed as separate layers, and the image processing with the input / output characteristics of Figure 13B(2) is applied to the character image layer, while not applying this image processing to the background image layer.

[0156] Then, by combining these layers, image processing with a characteristic of raising the low-brightness areas of the input image is performed only on the character image, as shown in Fig. 13B(2). Alternatively, after the character image layer and background image layer are combined, image processing with the input / output characteristics of Fig. 13B(2) may be performed only on the character image area.

[0157] Furthermore, the input / output image characteristics used in the image processing for boosting low-luminance regions of the input / output characteristics for the input image are not limited to the example shown in FIG. 13B(2). Any image processing for boosting low luminance may be used, including so-called brightness adjustment. Alternatively, image processing for improving visibility by controlling the gain that changes the weighting of Retinex processing, as disclosed in International Publication WO 2014 / 162533, may be performed.

[0158] According to the image processing of FIG. 13B(2) described above, it is possible to make the user aware of areas where black is drawn among areas where images of characters, objects, etc. are drawn without blending into the black background, thereby realizing a more suitable display.

[0159] 13A and 13B, the problems and more suitable image processing were explained using the space-floating image display device in which the background appears black (for example, the space-floating image display device 1000 in FIGS. 4A to 4G, or the space-floating image display device 1000 in the state where the rear window is shielded in FIGS. 4I and 4J). However, the image processing is also effective for devices other than these space-floating image display devices.

[0160] Specifically, in the space-floating image display device 1000 of Fig. 4H, or in Fig. 4I and Fig. 4J where the rear window is not shaded, the background of the space-floating image 3 is not black, but the scenery behind the space-floating image display device 1000 through the window. In this case, the same problems as those described in Fig. 13A and Fig. 13B exist.

[0161] That is, the part of the image of the character "panda" 1525, which is an object, that is drawn in black will blend into the scenery behind the space-floating image display device 1000 through the window. In this case too, by using the image processing of Fig. 13B(2), the part of the image of the character "panda" 1525, which is an object, that is drawn in black will be recognized as being distinct from the scenery behind the space-floating image display device 1000 through the window, improving the visibility of the object.

[0162] That is, by using the image processing of FIG. 13B(2), the area displaying the image of the object character "panda" 1525 can be recognized as distinct from the scenery behind the space floating image display device 1000 through the window, and it becomes possible to more easily recognize that the object character "panda" 1525 is in front of the scenery, improving the visibility of the object.

[0163] 4K, 4L, and 4M, as described above, when another image (such as an image from the transmissive self-luminous image display device 1650 or an image from the second display device 1680) is displayed at a position different in depth from the space-floating image 3, the background of the space-floating image 3 is not black, but the other image. In this case, the problems explained in FIGS. 13A and 13B also exist.

[0164] That is, the part of the image of the character "panda" 1525, which is an object, that is drawn in black will blend into the other image that is displayed at a different depth from the floating image in space 3. In this case as well, by using the image processing of Fig. 13B(2), the part of the image of the character "panda" 1525, which is an object, that is drawn in black will be able to be recognized as distinct from the other image, improving the visibility of the object.

[0165] In other words, by using the image processing of Figure 13B (2), the area displaying the image of the object character "panda" 1525 can be recognized as distinct from the other image, and it can be more easily recognized that the object character "panda" 1525 is in front of the other image, improving the visibility of the object.

[0166] An example of the image display process of this embodiment will be described with reference to Fig. 13C. Fig. 13C shows an example of the image display of this embodiment in which the space floating image 3 and a second image 2050, which is another image, are simultaneously displayed. The second image 2050 may correspond to the image displayed by the transmissive self-luminous image display device 1650 of Fig. 4K or Fig. 4L. The second image 2050 may also correspond to the image displayed by the second display device 1680 of Fig. 4M.

[0167] That is, the example of the image display in Fig. 13C shows a specific example of the image display examples of the space-floating image display device 1000 in Figs. 4K, 4L, and 4M. In the example of this figure, a bear character is displayed in the space-floating image 3. The area other than the bear character in the space-floating image 3 is displayed in black, and becomes transparent as a space-floating image. In addition, the second image 2050 is a background image in which a plain, a mountain, and a sun are drawn.

[0168] 13C, the floating in space image 3 and the second image 2050 are displayed at different depth positions. When the user 230 views the two images, the floating in space image 3 and the second image 2050, in the line of sight of the arrow 2040, the user 230 can view the two images in a superimposed state. Specifically, the bear character of the floating in space image 3 appears to be superimposed in front of the background of plains, mountains, and the sun depicted in the second image 2050.

[0169] Here, since the space floating image 3 is formed as a real image in the air, when the user 230 moves his / her viewpoint slightly, he / she can recognize the depth of the space floating image 3 and the second image 2050 due to parallax. Therefore, the user 230 can get a stronger sense of floating in space from the space floating image 3 while viewing the two images in an overlapping state.

[0170] An example of the video display process of this embodiment will be described with reference to Fig. 13D. Fig. 13D(1) is a diagram of the floating in space image 3, from the example of the video display of this embodiment in Fig. 13C, as seen from the line of sight of the user 230. Here, a bear character is displayed in the floating in space image 3. The area other than the bear character in the floating in space image 3 is displayed in black, and becomes transparent as a floating in space image.

[0171] 13D(2) is a diagram showing the second image 2050 in the example of the video display of this embodiment in FIG. 13C as viewed from the line of sight of the user 230. In the example of this figure, the second image 2050 is a background image in which a plain, a mountain, and a sun are drawn.

[0172] 13D(3) is a diagram showing the state in which the second image 2050 and the floating in space image 3 appear superimposed in the line of sight of the user 230, among the example of image display of this embodiment in Fig. 13C. Specifically, the bear character of the floating in space image 3 appears superimposed in front of the background of plains, mountains, and the sun drawn in the second image 2050.

[0173] Here, when simultaneously displaying the space-floating image 3 and the second image 2050, it is desirable to pay attention to the balance of brightness between the two images in order to ensure better visibility of the space-floating image 3. If the second image 2050 is too bright compared to the brightness of the space-floating image 3, the displayed image of the space-floating image 3 will be transparent, and the second image 2050, which is the background, will be strongly visible through it.

[0174] Therefore, the output of the light source of the spatially floating image 3 and the display image brightness of the display device 1, and the output of the light source of the display device displaying the second image 2050 and the display image brightness of the display device should be set so that at least the brightness per unit area of ​​the spatially floating image 3 at the display position of the spatially floating image 3 is greater than the brightness per unit area of ​​the image light that reaches the display position of the spatially floating image 3 from the second image 2050.

[0175] Note that this condition only needs to be satisfied when simultaneously displaying the space-floating image 3 and the second image 2050, and therefore when switching from the first display mode in which only the second image 2050 is displayed without displaying the space-floating image 3 to the second display mode in which the space-floating image 3 and the second image 2050 are simultaneously displayed, control may be performed to reduce the brightness of the second image 2050 by lowering the output of the light source of the display device that displays the second image 2050 and / or the display image brightness of the display device. These controls may be realized by the control unit 1110 in Fig. 3 controlling the display device 1 and the display device that displays the second image 2050 (the transmissive self-luminous image display device 1650 in Fig. 4K or Fig. 4L or the second display device 1680 in Fig. 4M).

[0176] Note that when switching from the above-described first display mode to the above-described second display mode, if control is performed to reduce the brightness of the second image 2050, the brightness may be reduced uniformly across the entire screen of the second image 2050. Alternatively, instead of reducing the brightness uniformly across the entire screen of the second image 2050, the brightness reduction effect may be greatest in the portion where an object is displayed in the space-floating image 3, and the brightness reduction effect may be gradually weakened around that portion. In other words, the visibility of the space-floating image 3 can be sufficiently ensured by reducing the brightness of the second image 2050 only in the portion where the space-floating image 3 is visually recognized as being superimposed on the second image 2050.

[0177] Here, since the space floating image 3 and the second image 2050 are displayed at positions with different depths, when the user 230 slightly changes his / her viewpoint, the parallax causes a change in the superimposed position of the space floating image 3 relative to the second image 2050. Therefore, when switching from the above-mentioned first display mode to the above-mentioned second display mode, if the brightness is to be reduced unevenly across the entire screen of the second image 2050, it is not desirable to reduce the brightness sharply based on the outline of the object displayed in the space floating image 3, but rather it is desirable to perform a gradation process of the brightness reduction effect, which changes the brightness reduction effect stepwise depending on the position as described above.

[0178] In addition, in the space floating image display device 1000 where the position of the object displayed in the space floating image 3 is approximately at the center of the space floating image 3, the position where the brightness reduction effect of the gradation processing of the brightness reduction effect is greatest can be the center position of the space floating image 3.

[0179] According to the image display process of this embodiment described above, the user 230 can visually recognize the space floating image 3 and the second image 2050 more favorably.

[0180] Note that when displaying the space-floating image 3, control may be performed so as not to display the second image 2050. Since not displaying the second image 2050 increases the visibility of the space-floating image 3, this is suitable for applications such as the space-floating image display device 1000 where the user must be able to reliably view the space-floating image 3 when the space-floating image 3 is displayed.

[0181] <Example 2> As Example 2 of the present invention, an example of a foldable configuration of a space-floating image display device will be described. Note that the space-floating image display device according to this example is a foldable configuration of the space-floating image display device described in Example 1. In this example, differences from Example 1 will be described, and repeated explanations of the same configuration and similarities as in Example 1 will be omitted. Note that in the following description of the example, the expression "store" does not only mean completely storing an element in a certain place. In other words, the expression "store" is used even when an element is partially stored in a certain place and partially exposed. Therefore, there is no problem in reading "store" as "hold." In this case, "store" can be read as "hold" and "stored" can be read as "held."

[0182] Fig. 14A shows an example of a foldable space-floating image display device 1000. The space-floating image display device 1000 of Fig. 14A has multiple housings, namely housing A1711 and housing B1712. Housing A1711 and housing B1712 are connected via a polarizing mirror holder 1750 that holds a polarization separating member 101B, which is a polarizing mirror. A rotation mechanism 1751 is provided at the connection between the polarization mirror holder 1750 and housing A1711, and the rotation function of the rotation mechanism 1751 is configured to change the relative angle between the polarization mirror holder 1750 (and the polarization separating member 101B) and housing A1711. A rotation mechanism 1752 is provided at the connection between the polarizing mirror holder 1750 and the housing B 1712, and the rotation function of the rotation mechanism 1752 is configured to change the relative angle between the polarizing mirror holder 1750 (and the polarization separation member 101B) and the housing B 1712.

[0183] Here, a state (usage state) will be described in which the housing A1711, housing B1712, and polarization separator 101B are arranged in front of the user 230 at an angle that forms the letter N shown in Fig. 14A(1). The arrangement of the housing A1711, housing B1712, and polarization separator 101B at this angle may also be referred to as an N-shaped arrangement.

[0184] In the following embodiments, various configurations, functions, and modifications of the foldable space-floating image display device 1000 will be described. In these descriptions, various configurations, functions, and modifications other than those limited to the folding function can also be various configurations, functions, and modifications of the space-floating image display device with an N-shaped arrangement. In other words, these various configurations, functions, and modifications are also effective for the space-floating image display device with an N-shaped arrangement that does not have a folding function.

[0185] Here, display device 1 having light source device (hereinafter also simply referred to as light source) 13 and liquid crystal display panel 11 displays an image, and image light from display device 1 is emitted to polarization separation member 101B. Of the image light from display device 1, light that passes through polarization separation member 101B passes through λ / 4 plate 21, is reflected by retroreflector 2, passes through λ / 4 plate 21 again, and is emitted to polarization separation member 101B. The light that is emitted from λ / 4 plate 21, enters polarization separation member 101B, and reflected by polarization separation member 101B forms a spatially floating image 3.

[0186] The details of the optical system in this embodiment for forming the floating image 3 in space have already been explained in Figures 2 and 4 of Example 1, and therefore a repeated explanation will be omitted. The details of the light source 13 of the display device 1 in this embodiment have already been explained in Figures 5 to 12 of Example 1, and therefore a repeated explanation will be omitted.

[0187] 2 and 4 in the first embodiment, an absorptive polarizing plate 12 may be provided on the image display surface of the liquid crystal display panel 11. The space floating image display device of this embodiment may be configured to have each element shown in the block diagram of the internal configuration shown in Fig. 3. In this case, each element shown in the housing 1190 in Fig. 3 may be configured to be stored or held in any of the housing A1711, housing B1712, and polarizing mirror holder 1750.

[0188] However, if elements that require wiring of power supply lines from power supply 1106 in Figure 3 (various circuit boards, various processing units, various interfaces, various sensors, etc.) or elements that require wired connection to control unit 1110 are placed separately in housing A1711 and housing B1712, it will be necessary to wire power supply lines and wired control signal lines through the internal structure of rotation mechanism 1751, rotation mechanism 1752, and polarizing mirror holder 1750, making the structure complex.

[0189] Therefore, components that require a power supply and components that require a wired signal line connection It is preferable to configure the product to be stored in the housing A1711 that stores the display device 1, which necessarily requires a power supply. In this case, there is no need to wire power supply lines or wired control signal lines through the internal structures of the rotation mechanism 1751, the rotation mechanism 1752, and the polarizing mirror holder 1750, and it is possible to provide the space floating image display device 1000 at a lower cost. Therefore, for the same reason, it is preferable to store the power supply 1106 and the secondary battery 1112 in the housing A1711 that stores the display device 1, which has a power supply that operates using these electric powers.

[0190] 14A(1), the optical path from the display device 1 to the retroreflector 2 through which the image light forms the space-floating image 3 requires a predetermined optical path length. Therefore, in the usage state, the space-floating image display device 1000 requires a space of a predetermined volume between the housing A1711 and the opposing housing B1712, which includes at least the range of the light beam in the optical path of the image light from the display device 1 to the retroreflector 2.

[0191] In the case of each of the space-floating image display devices 1000 of the first embodiment of the present invention, for example, in Fig. 4, even when the space-floating image display device 1000 is not in use, a space of a predetermined volume including the range of the light beam in the optical path of the image light reaching the retroreflector 2 from the display device 1 is maintained as it is in the housing of each of the space-floating image display devices 1000, even when the space-floating image display device 1000 is not in use. Therefore, the space-floating image display device 1000 of the first embodiment of the present invention, for example, in Fig. 4, is large in volume even when not in use, and there is room for improvement in terms of portability and storability.

[0192] 14A, in order to allow image light from the display device 1 to form the space-floating image 3 via the retroreflector 2, the relative angles of the housing A1711, housing B1712, and polarization separation member 101B are arranged at angles as shown in Fig. 14A(1). Specifically, a stopper is provided in the rotation mechanism 1751 to limit the adjustment range of the relative angle between the housing A1711 and the polarizing mirror holder 1750, and the upper limit of the angle at which the housing A1711 and the polarizing mirror holder 1750 open is set to the angle shown in Fig. 14A(1).

[0193] Furthermore, a stopper may be provided in rotation mechanism 1752 to limit the adjustment range of the relative angle between housing B 1712 and polarizing mirror holder 1750, so that the upper limit of the angle at which housing B 1712 and polarizing mirror holder 1750 open becomes the angle shown in Fig. 14A(1). Rotation mechanisms 1751, 1752, and the stopper may be configured using existing technology.

[0194] Furthermore, the space-floating image display device 1000 of Fig. 14A is configured so that the rotation mechanism 1751 rotates the housing A1711 in the direction of the thick arrow shown in Fig. 14A(1), thereby deforming the space-floating image display device 1000 so that the relative angle between the housing A1711 and the polarizing mirror holder 1750 becomes smaller. Furthermore, the rotation mechanism 1752 rotates the housing B1712 in the direction of the thick arrow shown in Fig. 14A(1), thereby deforming the space-floating image display device 1000 so that the relative angle between the housing B1712 and the polarizing mirror holder 1750 becomes smaller. The shape of the space-floating image display device 1000 after this deformation is shown in Fig. 14A(2). Hereinafter, the folded state of the space-floating image display device 1000 as shown in Fig. 14A(2) will be referred to as the folded state.

[0195] Here, the maximum volume of the outer shape of the space-floating image display device 1000 is defined as the volume obtained by multiplying the maximum width (x direction), maximum depth (y direction), and maximum height (z direction) of the outer shape of the space-floating image display device 1000. The maximum volume of the space-floating image display device 1000 in the folded state shown in Fig. 14A(2) is smaller than the maximum volume of the space-floating image display device 1000 in the used state shown in Fig. 14A(1). Therefore, in the example shown in Fig. 14A, when the user 230 uses the space-floating image display device 1000, he or she views the space-floating image 3 in the used state shown in Fig. 14A(1), and when not using the space-floating image display device 1000, he or she uses the space-floating image display device 1000 in the folded state shown in Fig. 14A(2), thereby reducing the maximum volume and making it easier to carry and store the device.

[0196] 14A(2), the floating image 3 cannot be formed. Therefore, in the folded state, it is not necessary to emit image light from the display device 1, and it is preferable to turn off the light source 13 of the display device 1. The control of turning off the light source 13 of the display device 1 when transitioning from the use state to the folded state may be performed by the control unit 1110 based on a user operation via the operation input unit 1107 of FIG.

[0197] 14A(1) and 14A(2), an open / close sensor 1741 may be provided to detect whether the space floating image display device 1000 is in a folded state, and the light source 13 of the display device 1 may be turned off based on the detection result of the open / close sensor. The open / close sensor 1741 may be configured, for example, as an approach detection sensor using infrared rays. The approach detection sensor may be configured as an active infrared sensor that emits sensing light such as infrared rays and detects the reflected light of the sensing light.

[0198] Here, in consideration of the efficiency of wired connection, it is preferable that the open / close sensor 1741, which requires a power supply, is stored in the housing A1711 that stores the display device 1, which necessarily requires a power supply. In this case, the open / close sensor 1741 may detect the distance between the housing A1711 and the polarizing mirror holder 1750, and detect that the space floating image display device 1000 has entered the folded state according to that distance.

[0199] Alternatively, the open / close sensor 1741 may detect the distance between the housing A1711 and the housing B1712, and detect that the space floating image display device 1000 has entered the folded state based on that distance. When detecting the distance between the housing A1711 and the housing B1712, the open / close sensor 1741, which is an active infrared sensor, may be configured to emit infrared sensing light that passes through the polarization separator 101B. The sensing light that passes through the polarization separator 101B may be reflected by the retroreflector 2, pass through the polarization separator 101B again, and return to the open / close sensor 1741.

[0200] In the description of the first embodiment, the image light forming the space-floating image 3 passes through the λ / 4 plate 21 twice, before and after reflection by the retroreflector 2, and is therefore reflected by the polarization separator 101B, which differs from the transmission characteristics and reflection characteristics of the sensing light emitted by the open / close sensor 1741. Therefore, in order to configure the infrared sensing light emitted by the open / close sensor 1741, which is an active infrared sensor, to pass through the polarization separator 101B again and return to the open / close sensor 1741, it is necessary to make the optical characteristics of the polarization separator 101B different for visible light, which is the image light forming the space-floating image 3, and infrared, which is the invisible sensing light emitted by the open / close sensor 1741, which is an active infrared sensor. For example, the infrared region may be configured to have a predetermined transmittance, such as approximately 50%, regardless of the polarization state.

[0201] As explained above, by providing the open / close sensor 1741, it is possible to more effectively detect that the space-floating image display device 1000 is in the folded state. Also, when the open / close sensor 1741 detects that the space-floating image display device 1000 is in the folded state, it is possible to more effectively control the turning off of the light source 13 of the display device 1.

[0202] Next, FIG. 14B shows a perspective view of an example of the space-floating image display device 1000 in use. FIG. 14B shows the space-floating image display device 1000 of FIG. 14A as an example. In use as shown in FIG. 14B, the housing A 1711, housing B 1712, and polarization separator 101B are arranged in front of the user 230 at an angle that forms the letter N, similar to FIG. 14A(1). The polarization separator 101B is held by a polarizing mirror holder 1750. The user can view the space-floating image 3 formed in front of the polarization separator 101B. In the example shown in this figure, a rabbit character is displayed on the space-floating image 3. As described above with reference to FIG. 14B, the space-floating image display device 1000 with the folding function of this embodiment allows the space-floating image 3 to be viewed favorably in use.

[0203] Next, using Fig. 14C, we will explain a foldable space floating image display device 1000, which is a modified example of Fig. 14A. In the explanation of Fig. 14C, we will explain the differences from Fig. 14A, and will omit repeated explanations of the same configuration and similarities as Fig. 14A.

[0204] The example of FIG. 14C is an example of a configuration example in which the foldable space-floating image display device 1000 is provided with an imaging unit 1180, an aerial operation detection unit 1350, etc. The housing A1717 of FIG. 14C extends closer to the user 230 than the housing A1711 of FIG. 14A. The front surface of the housing A1717 (the surface facing the user 230) extends to a position closer to the user 230 than the space-floating image 3. In the example of FIG. 14C, the aerial operation detection unit 1350 is provided in this extended portion of the housing A1717. This makes it possible to detect operations by the user 230 on the surface including the space-floating image 3 when the space-floating image display device 1000 is in use as shown in FIG. 14C(1). The configuration and function of the aerial operation detection unit 1350 are the same as those described in the first embodiment, and therefore repeated description will be omitted.

[0205] 14C, an imaging unit 1180 may be provided on the front surface (the surface on the user 230 side) of the housing A1717 at a portion extending closer to the user 230 than the housing A1711 of FIG. 14A. This allows the imaging unit 1180 to capture an image of the user 230 when the space-floating image display device 1000 is in use as shown in FIG. 14C(1). The control unit 1110 may perform an identification process to determine who the user 230 is based on the image captured by the imaging unit 1180. The imaging unit 1180 may capture an image of the user 230 operating the space-floating image 3 and the area around the user 230, and the control unit 1110 may perform an identification process to determine whether the user 230 is in front of the space-floating image display device 1000 based on the captured image. The control unit 1110 may also calculate the distance from the user 230 to the space-floating image display device 1000 based on the captured image.

[0206] Here, in the space floating image display device 1000, when the imaging unit 1180, the mid-air operation detection unit 1350, etc. are provided, it is preferable to provide them on the housing A1717 side as shown in Fig. 14C, not on the housing B1718 side. The reason for this is that, as explained in Fig. 14A, it is preferable to configure it so that components that require a power supply and components that require a wired signal line connection are stored on the housing A side where the display device 1 that necessarily requires a power supply is stored.

[0207] As shown in FIG. 14C, even if the imaging unit 1180 and the aerial operation detection unit 1350 are provided near the front of the housing A1717, the folding function can be maintained, as in the folded state shown in FIG. 14C(2).

[0208] As explained above, according to the space-floating image display device 1000 of Fig. 14C, it is possible to more suitably equip the foldable space-floating image display device with a function for detecting user's mid-air operation. Also, according to the space-floating image display device 1000 of Fig. 14C, it is possible to equip the foldable space-floating image display device with an imaging function for imaging the user.

[0209] Example 3 Next, as a third embodiment of the present invention, a space-floating image display device 1000 capable of three-dimensional display using motion parallax will be described. The space-floating image display device according to this embodiment is configured by incorporating an imaging device into the configuration of the space-floating image display device described in the first or second embodiment, and is configured to be able to detect the position of the user's viewpoint, etc.

[0210] Furthermore, the space-floating image display device according to this embodiment can display an image generated (rendered) based on 3D data on the space-floating image 3, and by varying the generation process (rendering process) of the image according to the position of the detected viewpoint, etc., it is possible to allow the user to see a pseudo-stereoscopic image of the 3D model of the 3D data. In this embodiment, differences from embodiment 1 and embodiment 2 will be explained, and repeated explanations of the same configurations and similarities as embodiment 1 and embodiment 2 will be omitted.

[0211] An example of a space-floating image display device capable of stereoscopic display using motion parallax will be described using the space-floating image display device 1000 in Fig. 15A. Note that in the description of the configuration in Fig. 15A, differences from Fig. 14C will be described, and repeated description of the same configuration as Fig. 14C will be omitted.

[0212] The space floating image display device 1000 acquires 3D data about 3D models such as 3D objects and 3D characters via the communication unit 1132 and removable media interface 1134 in Fig. 3 and stores it in the storage unit 1170. When in use, the data is expanded from the storage unit 1170 to the memory 1109 and used by the image control unit 1160 or a GPU (Graphic Processing Unit) different from the image control unit 1160.

[0213] 15A, the space floating image display device 1000 is equipped with an imaging unit 1180. Based on the captured image of the imaging unit 1180, the position of the face or eyes of the user 230, the position between the eyes, etc. are detected as position information of the viewpoint. These positions are detected not only in the direction parallel to the plane of the space floating image 3, but also in the direction corresponding to the depth direction of the space floating image 3.

[0214] That is, the position in any of the x, y, and z directions in FIG. 15A is detected. The control unit 1110 in FIG. 3 may control these detection processes. Furthermore, the detection processes may use existing face detection technology, eye position detection technology, or viewpoint detection technology. The number of image capture units 1180 is not limited to one, and if necessary for accuracy, image capture units may be provided in two or more different positions and these positions may be detected based on a plurality of captured images. In general, the more image capture units are provided in different positions, the more accurately face detection, eye position detection, or viewpoint detection can be performed.

[0215] In the space floating image display device 1000 of Fig. 15A, the position of the stereoscopic image of the 3D model of the 3D data is set to a position in real space under the control of the control unit 1110 of Fig. 3. In Fig. 15A, the control unit 1110 sets a virtual spatial area 2101 corresponding to a bounding box indicating the spatial area in which the 3D model exists in the 3D data, and a virtual reference point 2102 which serves as a reference point for motion parallax in the stereoscopic vision of the 3D model of the 3D data.

[0216] The position of the virtual reference point 2102 on the horizontal plane may be the geometric center or the geometric center of gravity of a main object of the 3D model in a horizontal cross section, or may be near one of these points. The position of the virtual reference point 2102 on the horizontal plane may also be the geometric center or the geometric center of gravity of a bounding box that indicates the spatial region in which the 3D model exists. Regarding the vertical position of the virtual reference point 2102, if a surface equivalent to the ground exists in the 3D data, setting the position of the surface equivalent to the ground will enable a more natural stereoscopic effect to be achieved.

[0217] 15A, a virtual spatial region 2101 in which a 3D model exists is set at a position on the far side as viewed from the user relative to the real image of the floating-in-space image 3. A virtual reference point 2102, which serves as a reference point for motion parallax in the stereoscopic vision of a 3D model, is also set at a position on the far side as viewed from the user relative to the real image of the floating-in-space image 3. Here, a position on the far side as viewed from the user relative to the real image of the floating-in-space image 3 means a position shifted by a predetermined distance in a second direction (positive y direction in this figure), which is opposite to the first direction, relative to the real image of the floating-in-space image 3, in the optical arrangement of the floating-in-space image display device 1000, when the traveling direction of the chief ray of light forming the real image of the floating-in-space image 3 is defined as a first direction (negative y direction in this figure).

[0218] In the space-floating image display device 1000 of FIG. 15A, the light beam that passes through the retroreflector 2 reaches the space-floating image 3, which is a real image, so the position shifted by a predetermined distance in the second direction (positive y direction in this figure) means a position shifted by a predetermined distance toward the retroreflector 2 with respect to the position of the space-floating image 3, on the optical path of the light beam from the retroreflector 2 to the space-floating image 3, which is a real image.

[0219] Note that information on the settings of the virtual spatial region 2101 and the settings of the virtual reference point 2102 may be stored in the storage unit 1170 or nonvolatile memory 1108 in Fig. 3 in association with the 3D data of the 3D model under the control of the control unit 1110 in Fig. 3. When in use, the information may be read from the storage unit 1170 or nonvolatile memory 1108 and expanded in the memory 1109 for use. Also, under the control of the control unit 1110, the information may be transmitted to the video control unit 1160 or a GPU (Graphic Processing Unit) different from the video control unit 1160, and controlled to be used by the control unit or processing unit.

[0220] The effects of setting the virtual space area 2101 and the virtual reference point 2102 as described above in the space floating image display device 1000 of FIG. 15A will be described later.

[0221] Next, the specific processing of the three-dimensional display by the motion parallax in the space-floating image display device 1000 of Fig. 15A will be explained using Fig. 15B. Fig. 15B is a diagram showing the details of the positional relationship between the optical elements of the space-floating image display device 1000 of Fig. 15A, the virtual space area 2101, and the virtual reference point 2102. Also, in the space-floating image display device 1000 of Fig. 15A, as explained in Fig. 15A, the position of the face or eyes of the user 230, the position between both eyes, etc. are detected as the position information of the viewpoint based on the captured image of the imaging unit 1180.

[0222] 15B shows viewpoint position A, viewpoint position B, and viewpoint position C as examples of viewpoint positions of user 230. At each position, user 230 can visually recognize a 3D model existing in virtual space area 2101. In order for user 230 to pseudo-stereoscopically view the 3D model existing in space area 2101, it is necessary to display different rendering images in the space floating image 3 at viewpoint position A, viewpoint position B, and viewpoint position C of user 230, which have different viewing angles.

[0223] In FIG. 15B, the position of a virtual retroreflector 2' is shown at a position symmetrical to the retroreflector 2 with respect to the polarization separating member 101B as a reference.

[0224] Next, a visual recognition example of a 3D model on the space floating image display device 1000 of Fig. 15A will be described with reference to Fig. 15C. Fig. 15C describes an example in which a 3D model 2015 of a bear character is displayed.

[0225] Fig. 15C(1) shows a display example and a viewing example of the 3D model 2105 viewed from the user viewpoint position C in Fig. 15B. Fig. 15C(2) shows a display example and a viewing example of the 3D model 2105 viewed from the user viewpoint position B in Fig. 15B. Fig. 15C(3) shows a display example and a viewing example of the 3D model 2105 viewed from the user viewpoint position A in Fig. 15B.

[0226] That is, the 3D model 2015 of the bear character is rendered by varying the angle of the viewpoint in the rendering process of the 3D model so as to correspond to the viewpoint positions of multiple users at different angles. Since it is desirable to follow changes in the user viewpoint position, it is desirable that this rendering be a so-called real-time rendering process. The rendering process of the 3D model of such 3D data may be performed by the video control unit 1160 under the control of the control unit 1110 in FIG. 3.

[0227] Furthermore, a GPU (Graphics Processing Unit) different from the video control unit 1160 may be provided to perform real-time rendering. Note that these display and visual examples of the 3D model 2105 are illustrations of rendered images, and may be considered to show the state of the mesh or texture of the 3D model after rendering.

[0228] An example of the boundary of the virtual spatial region 2101 corresponding to the bounding box indicating the spatial region in which the 3D model exists in the 3D data is shown in Fig. 15C(2). In other words, the virtual spatial region 2101 is a rectangular parallelepiped spatial region.

[0229] Next, a visual recognition example of a 3D model on the space floating image display device 1000 of Fig. 15A will be described with reference to Fig. 15C. Fig. 15C describes an example in which a 3D model 2015 of a bear character is displayed.

[0230] Fig. 15C(1) shows a display example and a viewing example of the 3D model 2105 viewed from the user viewpoint position C in Fig. 15B. Fig. 15C(2) shows a display example and a viewing example of the 3D model 2105 viewed from the user viewpoint position B in Fig. 15B. Fig. 15C(3) shows a display example and a viewing example of the 3D model 2105 viewed from the user viewpoint position A in Fig. 15B.

[0231] That is, the 3D model 2015 of the bear character is rendered by varying the angle of the viewpoint in the rendering process of the 3D model so as to correspond to the viewpoint positions of multiple users at different angles. Since it is desirable to follow changes in the user viewpoint position, it is desirable that this rendering be a so-called real-time rendering process. The rendering process of the 3D model of such 3D data may be performed by the video control unit 1160 under the control of the control unit 1110 in FIG. 3.

[0232] Furthermore, a separate GPU (Graphics Processing Unit) from the video control unit 1160 may be provided and the GPU may perform the processing. Note that these display and visual examples of the 3D model 2105 are illustrations of rendered images, and may be considered to show the state of the mesh or texture of the 3D model after rendering. Note that an example of a virtual spatial region 2101 corresponding to a bounding box indicating the spatial region in which the 3D model exists in 3D data is shown in FIG. 15C(2). In other words, the virtual spatial region 2101 is a rectangular parallelepiped spatial region.

[0233] Next, in the space floating image display device 1000 of FIG. 15A, a drawing example of an image in space floating image 3 for realizing the display example and viewing example explained in FIG. 15C will be explained using FIG. 15D.

[0234] FIG. 15D(1) shows an example of how an image is drawn in the space floating image 3 when the viewpoint position of the user 230 is viewpoint position A.

[0235] FIG. 15D(2) shows an example of how the image in the space floating image 3 is rendered when the viewpoint position of the user 230 is viewpoint position B.

[0236] Fig. 15D(3) shows an example of how an image is drawn in the space floating image 3 when the viewpoint position of the user 230 is viewpoint position C. Note that the example of Fig. 15D shows an example in which the midpoint between the detected positions of both eyes of the user is used as the viewpoint position of the user at any viewpoint position.

[0237] Here, in order to realize the display example and viewing example described in FIG. 15C, the position of the space-floating image 3, which is a real image existing in the real space in the space-floating image display device 1000, the detected user's viewpoint position, and the position of the 3D data space containing the 3D model are associated with the virtual space area 2101 and the virtual reference point 2102, and then the following processing is performed.

[0238] Specifically, pixel values ​​(brightness and chromaticity) calculated by calculation based on the texture pixels on the surface of the 3D model or object in the 3D data space where the line connecting the position in the 3D data space containing the 3D model and the detected user's viewpoint position intersect with the Space Floating Image 3 are mapped. This calculation takes into account the light source settings and shader settings at the time of rendering. This can also be expressed as a projection of the 3D data space onto the Space Floating Image 3 according to the user's viewpoint position.

[0239] This process can be explained as follows from the perspective of 3D data rendering processing. That is, in the rendering processing of a 3D model in 3D data space, the position in the 3D data space corresponding to the user's viewpoint position detected by the Space-Floating Image Display Device 1000 is set as the position of the camera at the time of rendering, and the planar area in the 3D data space corresponding to the display area of ​​the Space-Floating Image 3 of the Space-Floating Image Display Device 1000 (assumed to be a planar rectangle in the example of FIG. 15) is set as the angle of view of the camera at the time of rendering, and rendering to a 2D image is performed.

[0240] If the two-dimensional image resulting from the rendering is displayed on the display device 1 and focused as a space-floating image 3, it becomes possible to render an image that realizes the display and visual example of the 3D model 2105 described in Fig. 15C. Due to the pseudo-stereoscopic vision caused by motion parallax, the user 230 can visually recognize the 3D model as if it really exists in the virtual spatial region 2101, near the virtual reference point 2102.

[0241] 15D(1), (2), and (3) illustrate, as an explanatory example, the projection of the vertices of a virtual space region 2101 and a virtual reference point 2102 onto the space floating image 3. In the example of FIG. 15D(1), the projection results of these points are shown as intersection 2106. In the example of FIG. 15D(2), the projection results of these points are shown as intersection 2107. In the example of FIG. 15D(3), the projection results of these points are shown as intersection 2108.

[0242] In the example of Figure 15D (1) (2) (3), an example is explained in which the user's viewpoint position changes on the XY plane, but the principle is the same when the user's viewpoint position changes in the vertical direction (z direction), and the processing is also the same because only the axial direction changes. Also, the principle is the same when the user's viewpoint position changes in the depth direction (y direction), and the processing is also the same because only the axial direction changes. Therefore, even when the user's viewpoint position changes in three dimensions, it is possible to handle it with the projection processing onto the Space Floating Image 3 of the 3D data space according to the user's viewpoint position described above, or the rendering processing described above.

[0243] Next, as explained in FIG. 15A, in the space-floating image display device 1000, the effect of setting the virtual spatial area 2101 corresponding to the bounding box indicating the spatial area where the 3D model exists at a position on the far side as seen from the user relative to the space-floating image 3 which is a real image, and the effect of setting the virtual reference point 2102 which is the reference point for motion parallax in the stereoscopic vision of the 3D model at a position on the far side as seen from the user relative to the space-floating image 3 which is also a real image, will be explained using FIG. 15E.

[0244] 15E(1) shows, as a comparative example different from the present invention, an example of stereoscopic processing using motion parallax on a fixed pixel display 2110 having a display surface on the user 230 side. The size of the display area of ​​the display screen of the fixed pixel display 2110 is assumed to be the same as the size of the display area of ​​the floating-in-space image. The viewing position A of the user 230 is assumed to be the same position as the viewing position A in the other diagrams of FIG.

[0245] 15E(1), in order to ensure a wide viewing angle that allows the user 230 to view stereoscopically favorably, it is preferable to set the virtual spatial area 2101 corresponding to the bounding box indicating the spatial area in which the 3D model exists and the virtual reference point 2102 that serves as the reference point for motion parallax near the display surface of the fixed pixel display 2110. This is because by doing so, it is possible to minimize the projection area required when projecting the virtual spatial area 2101 corresponding to the bounding box indicating the spatial area in which the 3D model exists onto the surface of the fixed pixel display 2110.

[0246] In the example of FIG. 15E(1), at viewing position A of user 230, the user can view the 3D model displayed in virtual space area 2101 without vignetting.

[0247] In contrast to this, Fig. 15E(2) is an example assuming that an attempt is made to set a virtual space area 2101 and a virtual reference point 2102 in the space-floating image display device 1000, similar to the stereoscopic processing by suitable motion parallax on the fixed pixel display 2110 of Fig. 15E(1). The display area of ​​the space-floating image 3 of Fig. 15E(2) is the same size as the display area of ​​the fixed pixel display 2110 of Fig. 15E(1), and the viewing position A of the user 230 is also the same in Fig. 15E(2) and Fig. 15E(1).

[0248] Here, Figure 15E(2) shows the position of the virtual retroreflector 2' shown in Figure 15B. In other words, Figure 15E(2) shows a schematic diagram that shows a linear optical path from the retroreflector 2 to the floating image 3 by illustrating the virtual retroreflector 2', eliminating the geometrical reflection caused by the polarization separation mirror 101B. Here, we consider how a line of sight 2190 that is from a viewing position A of the user 230 and passes through a virtual spatial region 2101 corresponding to a bounding box that indicates the spatial region where the 3D model exists is viewed by the user 230.

[0249] In this case, the intersection of the line of sight 2190 from the viewing position A of the user 230 and the plane of the space-floating image 3 is included in the display area of ​​the space-floating image 3, and the geometric relationship is no different from the relationship between the viewing position A of the user 230 and the display area in Fig. 15E(1). However, there is no virtual retroreflector 2' on the extension line of the line of sight 2190 in Fig. 15E(2). This means that in the space-floating image display device 1000, the light beam that passes through the retroreflector 2 to form the space-floating image 3 does not include light that enters the viewing position A of the user 230 from the angle of the line of sight 2190.

[0250] That is, in the example of Figure 15E(2), a part of the virtual spatial area 2101 corresponding to the bounding box indicating the spatial area in which the 3D model exists is vignetted by the range of the virtual retroreflector 2', as in the line of sight 2190.

[0251] That is, in a space-floating image display device that forms the space-floating image 3 by a light beam that has passed through the retroreflective member 2, unlike the fixed pixel display 2110, it is not sufficient to simply consider vignetting of the 3D model due to the relationship between the display area of ​​the space-floating image 3 on the display surface and the setting of the virtual space area 2101. In a space-floating image display device that forms the space-floating image 3 by a light beam that has passed through the retroreflective member 2, it is necessary to set the position of the virtual space area 2101 that corresponds to the bounding box that indicates the space area where the 3D model exists, and the position of the virtual reference point 2102 that serves as the reference point for motion parallax in the stereoscopic vision of the 3D model, taking into consideration the geometric position and range of the area of ​​the retroreflective member 2 in addition to the display area of ​​the space-floating image 3 on the display surface with respect to the user's viewing position.

[0252] Therefore, Fig. 15E(3) shows an example of setting the position of a virtual spatial area 2101 corresponding to a bounding box indicating the spatial area where a 3D model exists, and setting the position of a virtual reference point 2102 serving as a reference point for motion parallax in the stereoscopic vision of the 3D model, which are adopted in the space-floating image display device 1000 according to this embodiment described in Fig. 15A. In the example of Fig. 15E(3), compared to Fig. 15E(2), the position of the virtual spatial area 2101 corresponding to a bounding box indicating the spatial area where a 3D model exists, and the position of the virtual reference point 2102 serving as a reference point for motion parallax in the stereoscopic vision of the 3D model are set by dy further back from the display surface of the space-floating image 3, which is a real image, as seen from the user (a position shifted in the opposite direction to the traveling direction of the chief ray of the light beam).

[0253] As illustrated in Fig. 15E(3), the virtual retroreflector 2' exists on the extension of all lines of sight that pass through a part of the virtual space area 2101 from the viewing position A of the user 230. That is, in the example of Fig. 15E(3), at the viewing position A of the user 230, the user can view the 3D model displayed in the virtual space area 2101 without vignetting.

[0254] As described above, in the space-floating image display device 1000 according to this embodiment, as shown in FIG. 15E(3), by shifting and setting the position of the virtual reference point 2102, which is the reference point for motion parallax in the stereoscopic vision of a 3D model, in the opposite direction to the traveling direction of the chief ray of the light beam that forms the space-floating image 3, it is possible to realize a display method for a space-floating image that realizes a more suitable stereoscopic vision of a 3D model with less vignetting.

[0255] It should be noted that the virtual spatial area 2101 corresponding to the bounding box indicating the spatial area in which the 3D model exists does not necessarily have to be set so that all of the space is on the far side of the display surface of the Floating in Space Image 3 as seen from the user, but according to the above-mentioned principle, it is preferable to set all of the space of the virtual spatial area 2101 so that all of the space is on the far side of the display surface of the Floating in Space Image 3 as seen from the user, as this can further reduce the occurrence of vignetting of the 3D model.

[0256] Next, using Figure 15F, an example of setting a virtual spatial area 2101 corresponding to a bounding box when the space floating image display device 1000 of this embodiment displays a 3D character model as a 3D model, and an example of setting a virtual reference point 2102 that serves as a reference point for motion parallax in the stereoscopic vision of the 3D model will be described.

[0257] Figure 15F shows the positional relationship between a 3D model 2105 and a bounding box 2120 in 3D data for a 3D character model. The 3D model 2105 is indicated by dotted lines, depicting the mesh surfaces or textures of the 3D model. The bounding box 2120 is set as a rectangular parallelepiped that contains the 3D model 2105. The octahedrons, consisting of two rectangular pyramids stacked one on top of the other, are called bones or armatures, and are elements that mimic the human skeleton. They are primarily located inside and along the 3D model 2105. These are required for animating the 3D model. Setting bones or armatures in a 3D model is sometimes referred to as rigging. Setting bones or armatures can also be done in a humanoid format.

[0258] The example in Figure 15F shows the configuration of a 3D model with bones set in humanoid format. To explain some of the types of bones in humanoid format, there are Hips 2111, Spine 2112, Chest 2113, Neck 2114, and Head 2115 near the center of the human skeleton, and these start at the bottom end of an octahedron and end at the top end. Near the feet of the human skeleton there are Foot 2116 (with L and R) and Toes 2117 (with L and R), and these end at the toe side of the octahedron and start at the opposite side. Bones corresponding to the shoulders, arms, and hands of the human skeleton are also shown, but their explanation will be omitted.

[0259] Here, when the space floating image display device 1000 of this embodiment displays a 3D character model with bones set as a 3D model and performs stereoscopic display using motion parallax, the following setting is preferable as an example of setting the virtual reference point 2102 that serves as the reference point for motion parallax. The following explanation is based on the premise that the 3D character is displayed facing the user as its default display posture. Specifically, the position of the virtual reference point 2102 that serves as the reference point for motion parallax in the stereoscopic vision of the 3D model in the left-right direction (x direction) as seen from the user is preferably set to the position 2125 of the start point or end point of Hips 2111, which is the buttocks bone, or in the vicinity of these.

[0260] In many cases, there is no difference in the left-right (x-direction) position of the start point and end point of any of the bones from the hip bone Hips 2111 to the head bone Head 2115. Therefore, it is desirable to set the left-right (x-direction) position of the virtual reference point 2102, which serves as the reference point for motion parallax in the stereoscopic vision of the 3D model, at or near the left-right (x-direction) position of any of the bones from the hip bone Hips 2111 to the head bone Head 2115.

[0261] Next, it is desirable to set the position in the depth direction (y direction) as seen from the user of virtual reference point 2102, which serves as the reference point for motion parallax in stereoscopic vision of a 3D model, at or near the position 2125 of the start point or end point of Hips 2111, the buttocks bone. Note that, if there is not a significant difference in the depth direction (y direction) positions of the start point and end point of any of the bones from Hips 2111, the buttocks bone, to Head 2115, the head bone, as seen from the user, the position in the depth direction (y direction) of virtual reference point 2102, which serves as the reference point for motion parallax in stereoscopic vision of a 3D model, may be set to the position in the depth direction (y direction) of any of the bones from Hips 2111, the buttocks bone, to Head 2115, or near the position.

[0262] Next, the ideal position in the vertical direction (z direction) of virtual reference point 2102, which serves as the reference point for motion parallax in the stereoscopic vision of a 3D model, varies depending on the type of 3D character. Specifically, if the 3D character stands on a reference plane such as the ground, it is estimated that the reference plane such as the ground is located immediately below Foot 2116, which is the foot bone, and Toes 2117, which is the toe bone, and therefore it is desirable to set the virtual reference point 2102 in a position vertically below or near the end point of Foot 2116, which is the foot bone, or the start or end point of Toes 2117, which is the toe bone.

[0263] In this way, even if the user moves the starting point up or down, the height in the vertical direction of the reference plane such as the ground does not change significantly, which further reduces the sense of incongruity.

[0264] As described above, when a 3D character model with bones set as a 3D model as explained in Fig. 15F is arranged as shown in Fig. 15E(3) in the space floating image display device 1000 according to this embodiment, it is more preferable to arrange it as follows. Specifically, in the xy plane, the position 2125 of the start or end point of Hips 2111, which is the buttocks bone, is arranged near the virtual reference point 2102, which is the reference point of motion parallax in the stereoscopic vision of the 3D model, so it is desirable that the position 2125 of the start or end point of Hips 2111, which is the buttocks bone of the 3D character model, is arranged at a position further back from the surface of the space floating image 3, which is a real image (a position shifted in the opposite direction to the traveling direction of the chief ray of the light beam) as seen from the user.

[0265] Furthermore, since it is desirable that the 3D model 2105 and bounding box 2120 be placed in a virtual spatial area 2101 that corresponds to the bounding box that indicates the spatial area in which the 3D model exists, it is desirable that all bones set in the 3D character model that are placed within the bounding box 2120 be placed at a position that is further back from the surface of the real image, the floating-in-space image 3, as seen from the user (a position shifted in the opposite direction to the traveling direction of the chief ray of the light beam).

[0266] According to the space floating image display device 1000 of this embodiment described above, the three-dimensional display using motion parallax can be performed more suitably.

[0267] The technology according to this embodiment displays high-resolution, high-brightness video information in a state where it floats in space, allowing users to operate the device without worrying about contact infection. Applying the technology according to this embodiment to a system used by an unspecified number of users reduces the risk of contact infection and makes it possible to provide a contactless user interface that can be used without anxiety. This contributes to the "Good Health and Well-Being" goal, one of the Sustainable Development Goals (SDGs) advocated by the United Nations.

[0268] Furthermore, the technology of this 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 retroreflector, thereby enabling high light utilization efficiency and producing bright and clear floating images in space.The technology of this embodiment can provide a highly usable non-contact user interface that can significantly reduce power consumption.This 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."

[0269] Various embodiments have been described above in detail. However, the present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments are detailed descriptions of the entire system to clearly explain the present invention, and the present invention is not necessarily limited to a system 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, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations. [Explanation of symbols]

[0270] 1...display device, 2...retroreflector (retroreflector), 3...spatial image (space-floating image), 105...window glass, 100...transparent member, 101...polarized light separation member, 101B...polarized light separation member, 12...absorptive polarizer, 13...light source device, 54...light direction conversion panel, 151...retroreflector, 102, 202...LED substrate, 203...light guide, 205, 271...reflective sheet, 206, 270...phase difference plate, 230...user, 1000...space-floating image display device, 1110...control unit, 1160...image control unit, 1180...imaging unit, 1102...image display unit, 1350...air operation detection unit, 1351...air operation detection sensor.

Claims

1. a video display unit that displays a video; a retroreflector onto which a light beam from the image display unit is incident; An imaging unit; A control unit; Equipped with The light beam reflected by the retroreflector forms a floating image in the air, which is a real image, the control unit is capable of setting a virtual position of a 3D model relative to the floating-in-the-air image, which is a real image; the video display unit displays a video resulting from a rendering process of 3D data of the 3D model based on the user's viewpoint position detected based on the captured image captured by the imaging unit and a virtual position of the 3D model, and in the floating-in-the-air video, which is a real image, a video for stereoscopic viewing due to motion parallax of the 3D model is displayed; The virtual position of the 3D model set by the control unit is a position shifted in the opposite direction to the traveling direction of the chief ray when the light beam reflected by the retroreflector forms the floating-in-the-air image, relative to the position of the floating-in-the-air image, which is a real image formed in the air. A floating video display device.

2. 2. The floating-in-the-air image display device according to claim 1, As the horizontal plane position of the virtual position of the 3D model set by the control unit, the position of the geometric center point in the horizontal cross section of a bounding box indicating the spatial region in which the 3D model exists is set to a position shifted in the opposite direction to the traveling direction of the chief ray when the light beam reflected by the retroreflector forms the floating-in-the-air image, relative to the position of the floating-in-the-air image, which is a real image formed in the air. A floating video display device.

3. 3. The airborne image display device according to claim 2, The entire range of the horizontal cross section of the bounding box indicating the spatial region in which the 3D model exists is set at a position shifted in the opposite direction to the traveling direction of the chief ray when the light beam reflected by the retroreflector forms the floating-in-the-air image, relative to the position of the floating-in-the-air image, which is a real image formed in the air. A floating video display device.

4. 2. The floating-in-the-air image display device according to claim 1, Furthermore, it is equipped with a GPU, The rendering process by the control unit is a real-time rendering process by a GPU. A floating video display device.

5. 2. The floating-in-the-air image display device according to claim 1, The Communications Department and A storage unit; Equipped with The 3D data of the 3D model is acquired via the communication unit, and the 3D data is stored in the storage unit; The rendering process is performed on the 3D data read from the storage unit. A floating video display device.

6. 2. The floating-in-the-air image display device according to claim 1, The Communications Department and A storage unit; a removable media interface; Equipped with acquiring the 3D data of the 3D model via the removable media interface and storing the 3D data in the storage unit; The rendering process is performed on the 3D data read from the storage unit. A floating video display device.

7. 2. The floating-in-the-air image display device according to claim 1, the control unit detects a midpoint between both eyes of the user as a viewpoint position of the user based on the captured image captured by the imaging unit; A floating video display device.

8. 2. The floating-in-the-air image display device according to claim 1, The display of the image for stereoscopic vision by motion parallax for the 3D model is performed by associating the position of the space floating image, which is a real image existing in real space, and the detected viewpoint position of the user with the spatial position of the 3D data including the 3D model, and mapping pixel values ​​calculated by calculation based on pixels of the texture of the surface of the 3D model that the straight line connecting the detected viewpoint position of the user and the position of the 3D model intersects with the space floating image. A floating video display device.

9. 9. The airborne image display device according to claim 8, The pixel-based calculation of the surface texture of the 3D model is performed based on the light source settings and shader settings at the time of rendering. A floating video display device.

10. a video display unit that displays a video; a retroreflector onto which a light beam from the image display unit is incident; An imaging unit; A control unit; Equipped with The light beam reflected by the retroreflector forms a real image, which is a floating image in the air. the control unit is capable of setting a virtual position of a 3D model relative to the floating-in-the-air image, which is a real image; the video display unit displays a video of a rendering process result of the 3D data of the 3D model based on the user's viewpoint position detected based on the captured image captured by the imaging unit and a virtual position of the 3D model, and in the floating-in-the-air video, which is a real image, a video for stereoscopic viewing due to motion parallax of the 3D model is displayed; the 3D model is a 3D model in which bones in a humanoid format are set, and in the virtual position of the 3D model set by the control unit, the starting point of the buttocks bone of the 3D model is arranged at a position shifted in a direction opposite to the traveling direction of a chief ray when a light beam reflected by the retroreflector forms the floating-in-the-air image, relative to the position of the floating-in-the-air image, which is a real image; A floating video display device.

11. The airborne image display device according to claim 10, At the virtual position of the 3D model set by the control unit, all bones set in the 3D model are arranged on the far side, as seen from the user, with respect to the position of the floating-in-the-air image, which is a real image. A floating video display device.

12. The airborne image display device according to claim 10, Furthermore, it is equipped with a GPU, The rendering process by the control unit is a real-time rendering process by a GPU. A floating video display device.

13. The airborne image display device according to claim 10, The Communications Department and A storage unit; Equipped with The 3D data of the 3D model is acquired via the communication unit, and the 3D data is stored in the storage unit; The rendering process is performed on the 3D data read from the storage unit. A floating video display device.

14. The airborne image display device according to claim 10, The Communications Department and A storage unit; a removable media interface; Equipped with acquiring the 3D data of the 3D model via the removable media interface and storing the 3D data in the storage unit; The rendering process is performed on the 3D data read from the storage unit. A floating video display device.

15. The airborne image display device according to claim 10, the control unit detects a midpoint between both eyes of the user as a viewpoint position of the user based on the captured image captured by the imaging unit; A floating video display device.

16. The airborne image display device according to claim 10, The display of the image for stereoscopic vision by motion parallax for the 3D model is performed by associating the position of the space floating image, which is a real image existing in real space, and the detected viewpoint position of the user with the spatial position of the 3D data including the 3D model, and mapping pixel values ​​calculated by calculation based on pixels of the texture of the surface of the 3D model that the straight line connecting the detected viewpoint position of the user and the position of the 3D model intersects with the space floating image. A floating video display device.

17. 17. The airborne image display device according to claim 16, The pixel-based calculation of the surface texture of the 3D model is performed based on the light source settings and shader settings at the time of rendering. A floating video display device.

Images