Aerial floating image display device

Abstract

To provide a more suitable aerial floating image display device. According to the present invention, it will contribute to Sustainable Development Goals (SDGs) "3 Good Health and Well-being," "9 Industry, Innovation and Infrastructure," and "11 Sustainable Cities and Communities." [Solution] The floating image display device comprises a display device, a polarization separation member, and a retroreflective member provided with a λ / 4 plate, and has a prism sheet positioned on the emission surface of the display device. The display device is positioned below the polarization separation member at a first inclination angle, and the floating image is positioned above the polarization separation member at the same inclination angle as the first inclination angle. The image light emitted from the display device is refracted by the prism sheet and incident on the polarization separation member at the first angle. The floating image is formed at a position that is mirror-symmetric with respect to the display device, with the polarization separation member as the boundary.

Description

Technical Field

[0001] The present invention relates to an airborne video display device.

Background Art

[0002] Regarding airborne information display technology, for example, it is disclosed in Patent Document 1.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the disclosure of Patent Document 1, considerations regarding configurations for obtaining practical brightness and quality of airborne video, and configurations for allowing users to view airborne video more enjoyably, etc. were not sufficient.

[0005] An object of the present invention is to provide a more suitable airborne video display device.

Means for Solving the Problems

[0006] To solve the above problems, for example, the configuration described in the claims may be adopted. The present application includes multiple means for solving the above problems, but one example is the following configuration: A floating image display device comprising: an image processing unit for performing image processing; a display unit for displaying the image processed by the image processing unit; and an optical system for generating a floating image based on the image displayed by the display unit, wherein the optical system comprises a polarization separation member and a retroreflective member with a λ / 4 plate on its incident surface, and the display unit comprises a display device for displaying an image and a prism sheet disposed on the image light output surface of the display device, wherein image light having a first polarization from the display unit is incident on the polarization separation member at a first angle, reflected by the polarization separation member, and the reflected image light is retroreflective by the retroreflective member and passes through the λ / 4 plate. The image light, which is converted to a second polarization by the polarizer and retroreflected, passes through the polarization separation member and is emitted at the same angle as the first, forming a floating image in the air at a position that is mirror-symmetric with respect to the display device with respect to the polarization separation member. The floating image is positioned at a first inclination angle with respect to the polarization separation member on the side of the user's viewpoint, and the display device is positioned at the same inclination angle as the first inclination angle with respect to the polarization separation member on the opposite side from the floating image. The image light emitted perpendicular to the surface from the image light emission surface of the display device is refracted by the prism sheet at a first refraction angle and incident on the polarization separation member at a first angle. [Effects of the Invention]

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

[0008] [Figure 1] This figure shows an example of how to use a spatially floating image display device according to one embodiment of the present invention. [Figure 2A] This figure shows an example of the main component configuration and retroreflective component configuration of a spatial floating image display device according to one embodiment of the present invention. [Figure 2B]This figure shows an example of the main component configuration and retroreflective component configuration of a spatial floating image display device according to one embodiment of the present invention. [Figure 2C] This figure shows an example of the main component configuration and retroreflective component configuration of a spatial floating image display device according to one embodiment of the present invention. [Figure 2D] This figure shows an example of the main components and retroreflective components of an aerial levitation image display device according to one embodiment of the present invention. [Figure 2E] This is a projection view of a retroreflective plate that constitutes an aerial levitation image display device according to one embodiment of the present invention. [Figure 2F] This is a top view of a retroreflective plate that constitutes an aerial levitation image display device according to one embodiment of the present invention. [Figure 2G] This is a perspective view showing a corner reflector that constitutes a retroreflective plate, which is part of an aerial floating image display device according to one embodiment of the present invention. [Figure 2H] This is a top view showing a corner reflector, which constitutes a retroreflective plate, as part of an aerial floating image display device according to one embodiment of the present invention. [Figure 2I] This is a side view showing a corner reflector, which constitutes a retroreflective plate, as part of an aerial floating image display device according to one embodiment of the present invention. [Figure 3] This figure shows an example of the configuration of a spatially floating image display device according to one embodiment of the present invention. [Figure 4A] This figure shows an example of the configuration of a spatially floating image display device according to one embodiment of the present invention. [Figure 4B] This figure shows an example of the configuration of a spatially floating image display device according to one embodiment of the present invention. [Figure 4C] This figure shows an example of the configuration of a spatially floating image display device according to one embodiment of the present invention. [Figure 4D] This figure shows an example of the configuration of a spatially floating image display device according to one embodiment of the present invention. [Figure 4E] This figure shows an example of the configuration of a spatially floating image display device according to one embodiment of the present invention. [Figure 4F]It is a diagram showing an example of the configuration of a spatial floating image display device according to an embodiment of the present invention. [Figure 4G] It is a diagram showing an example of the configuration of a spatial floating image display device according to an embodiment of the present invention. [Figure 4H] It is a diagram showing an example of the configuration of a spatial floating image display device according to an embodiment of the present invention. [Figure 4I] It is a diagram showing an example of the configuration of a spatial floating image display device according to an embodiment of the present invention. [Figure 4J] It is a diagram showing an example of the configuration of a spatial floating image display device according to an embodiment of the present invention. [Figure 4K] It is a diagram showing an example of the configuration of a spatial floating image display device according to an embodiment of the present invention. [Figure 4L] It is a diagram showing an example of the configuration of a spatial floating image display device according to an embodiment of the present invention. [Figure 4M] It is a diagram showing an example of the configuration of a spatial floating image display device according to an embodiment of the present invention. [Figure 4N] It is a diagram showing an example of the configuration of a spatial floating image display device according to an embodiment of the present invention. [Figure 4O] It is a diagram showing an example of the configuration of a spatial floating image display device according to an embodiment of the present invention. [Figure 4P] It is a diagram showing an example of the configuration of a spatial floating image display device according to an embodiment of the present invention. [Figure 5] It is a cross-sectional view showing an example of the specific configuration of a light source device according to an embodiment of the present invention. [Figure 6] It is a cross-sectional view showing an example of the specific configuration of a light source device according to an embodiment of the present invention. [Figure 7] It is a cross-sectional view showing an example of the specific configuration of a light source device according to an embodiment of the present invention. [Figure 8] It is an arrangement diagram showing the main part of a spatial floating image display device according to an embodiment of the present invention. [Figure 9] It is a cross-sectional view showing the configuration of a display device according to an embodiment of the present invention. [Figure 10] It is a cross-sectional view showing the configuration of a display device according to an embodiment of the present invention. [Figure 11] This is an explanatory diagram illustrating the light source diffusion characteristics of an image display device according to one embodiment of the present invention. [Figure 12] This is an explanatory diagram illustrating the diffusion characteristics of an image display device according to one embodiment of the present invention. [Figure 13A] This is an explanatory diagram illustrating an example of a problem that the image processing according to one embodiment of the present invention solves. [Figure 13B] This is an explanatory diagram of an example of image processing according to one embodiment of the present invention. [Figure 13C] This is an explanatory diagram illustrating an example of video display processing according to one embodiment of the present invention. [Figure 13D] This is an explanatory diagram illustrating an example of video display processing according to one embodiment of the present invention. [Figure 14] This figure shows an example of the main component configuration and retroreflective component configuration of a spatial floating image display device according to one embodiment of the present invention. [Figure 15] This figure shows an example of the optical system configuration of a comparative example spatial floating image display device according to one embodiment. [Figure 16] This figure shows an example of the optical system configuration of a comparative example spatial floating image display device according to one embodiment. [Figure 17] This figure shows an example of the optical system configuration for a spatially floating image display device according to one embodiment. [Figure 18] This figure shows an example of the configuration of a prism sheet according to one embodiment. [Figure 19] This figure shows an example configuration of a spatially floating image display device according to one embodiment. [Figure 20] This figure shows an example of the configuration of the housing of a spatially floating image display device according to one embodiment. [Figure 21] This figure shows an example configuration of a control unit and other components of a spatially floating image display device according to one embodiment. [Figure 22] This figure shows an example of the configuration of a spatially floating image in a comparative example spatially floating image display device according to one embodiment. [Figure 23] This figure shows an example of the configuration of a floating image in a floating image display device according to one embodiment. [Figure 24]This figure shows an example of setting up a virtual camera in a virtual 3D space according to one embodiment. [Figure 25] This figure shows an example of an image with a changed display angle according to one embodiment. [Figure 26] This is an explanatory diagram relating to the display depression angle according to one embodiment. [Figure 27] This figure shows an example of switching images using a switch button according to one embodiment. [Figure 28] This figure shows an example of a user settings screen according to one embodiment. [Figure 29] This figure shows an external device and a spatially floating image display device according to one embodiment. [Figure 30] This figure shows an example of a display showing the idling status, etc., according to one embodiment. [Figure 31] This is an explanatory diagram relating to the elevation angle of a face display according to one embodiment. [Figure 32] This figure shows an example of a video in which the elevation angle of the face display has been changed, according to one embodiment. [Figure 33] This figure shows an example of how a floating image in space appears according to one embodiment. [Figure 34] This figure shows an example configuration of a comparative example of a spatially floating image display device according to one embodiment. [Figure 35] This figure shows an example of the optical system configuration for a spatially floating image display device according to one embodiment. [Figure 36] This figure shows an example of the optical system configuration of a modified spatial floating image display device according to one embodiment. [Figure 37] This figure shows the first state of the angle adjustment mechanism in a spatially floating image display device according to one embodiment. [Figure 38] This figure shows a second state of the angle adjustment mechanism in a spatially floating image display device according to one embodiment. [Figure 39] This figure shows the third state of the angle adjustment mechanism in a spatially floating image display device according to one embodiment. [Figure 40] This figure shows an example of installation on a bottle holder according to one embodiment. [Figure 41]This figure shows one state of the angle adjustment mechanism in a spatially floating image display device according to one embodiment. [Figure 42] This figure shows an example of display control according to the state of the angle adjustment mechanism, according to one embodiment. [Figure 43] This figure shows an example of display control according to the state of the angle adjustment mechanism, according to one embodiment. [Figure 44] This figure shows an example of an image with adjusted display position and size according to one embodiment. [Figure 45] This figure shows an example of display control according to the state of the angle adjustment mechanism, according to one embodiment. [Figure 46] This figure shows an example of the configuration of the lower housing according to one embodiment. [Figure 47] This figure shows an example of the configuration of the lower housing according to one embodiment. [Figure 48] This figure shows the relationship between the number of selectable swivel angles and the number of selectable constant posture angles according to one embodiment. [Figure 49] This figure shows an example of the optical system configuration of a comparative example (first comparative example) of a spatially floating image display device according to one embodiment. [Figure 50] This figure shows an example of the optical system configuration of a spatial floating image display device according to one embodiment, specifically a comparative example (second comparative example). [Figure 51A] This figure shows an example of the optical system configuration of a spatially floating image display device according to one embodiment (when the angle of the retroreflector is 45 degrees). [Figure 51B] This figure shows an example of the optical system configuration of a spatially floating image display device according to one embodiment (when the angle of the retroreflector is set to 35 degrees). [Figure 51C] This figure shows an example of the optical system configuration of a spatially floating image display device according to one embodiment (when the angle of the retroreflector is set to 55 degrees). [Figure 52A] This figure shows an example of the cross-sectional configuration of a display device according to one embodiment. [Figure 52B] This figure shows an example of the cross-sectional configuration of a display device according to one embodiment (a modified example of a VCF). [Figure 53A]This figure shows an example of the configuration of a spatially floating image display device according to one embodiment (when the angle of the retroreflector is set to 45 degrees). [Figure 53B] This figure shows an example configuration of a spatially floating image display device according to one embodiment (when the angle of the retroreflector is set to 35 degrees). [Figure 53C] This figure shows an example of the configuration of a spatially floating image display device according to one embodiment (when the angle of the retroreflector is set to 55 degrees). [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described in detail below with reference to the drawings. However, the present invention is not limited to the examples described herein, and various modifications and alterations are possible by those skilled in the art within the scope of the technical ideas disclosed herein. Furthermore, in all the figures used to illustrate the present invention, components having the same function are given the same reference numerals, and repeated descriptions may be omitted.

[0010] The following embodiments relate to an image display device capable of transmitting an image generated by image light from an image light source through a transparent component that partitions a space, such as glass, and displaying it as a floating image in space outside the transparent component. In the following description of embodiments, the image floating in space is referred to as a "floating image in space." Instead of this term, other terms such as "aerial image," "spatial image," "floating image in space," "floating optical image of a displayed image," or "floating optical image of a displayed image in space" may be used. The term "floating image in space," which is mainly used in the description of embodiments, is used as a representative example of these terms.

[0011] According to the following embodiment, a suitable video display device can be realized for applications such as bank ATMs, train station ticket machines, and digital signage. For example, currently, bank ATMs and train station ticket machines typically use touch panels, but by using a transparent glass surface or a light-transmitting plate material, high-resolution video information can be displayed on this glass surface or light-transmitting plate material in a state of floating in space. At this time, by making the divergence angle of the emitted video light small, i.e., acute, and further aligning it to a specific polarization, only the normal reflected light is efficiently reflected by the retroreflector, resulting in high light utilization efficiency. This suppresses ghost images that occur in addition to the main floating image, which was a problem in conventional retroreflection methods, and allows for the acquisition of a clear floating image. Furthermore, the device including the light source of this embodiment can provide a novel and highly usable floating image display device (floating image display system) that can significantly reduce power consumption. In addition, for example, a floating image display device for vehicles can be provided that enables so-called unidirectional floating image display, which is visible inside and / or outside a vehicle.

[0012] <Example 1> Below, an example configuration of a spatially floating image display device will be described as Embodiment 1 of the present invention.

[0013] <An example of how a spatially floating image display device can be used> Figure 1 is a diagram showing an example of how to use a spatially floating image display device according to one embodiment of the present invention, and is a diagram showing the overall configuration of the spatially floating image display device according to this embodiment. The specific configuration of the spatially floating image display device will be described in detail using Figure 2, etc., but light with narrow-angle directivity and specific polarization is emitted from the image display device 1 as an image light beam, and after reflection in the optical system inside the spatially floating image display device, it enters the retroreflector plate 2, is retroreflected and passes through a transparent member 100 (glass, etc.), and forms an aerial image (spatially floating image 3), which is a real image, on the outside of the glass surface. In the following embodiments, the retroreflector plate 2 (retroreflective plate) will be used as an example of a retroreflective member. However, the retroreflector plate 2 of the present invention is not limited to a planar plate, but is used as an example of a concept that includes a sheet-like retroreflector attached to a planar or non-planar member, or the entire assembly in which a sheet-like retroreflector is attached to a planar or non-planar member. Furthermore, since the light rays reflected by the retroreflector 2 have imaging optical properties, the retroreflector 2 may also be described as an imaging optical member or imaging optical plate.

[0014] Furthermore, in stores and other similar establishments, the space is partitioned by a translucent material such as glass, called a "show window" (also known as "window glass") 105. According to the spatial floating image display device of this embodiment, it is possible to transmit such a transparent material and display the floating image in one direction to the outside and / or inside of the store (space).

[0015] In Figure 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 means for reflecting specific polarizations in the window glass 105, it is also possible to reflect the light and form an aerial image at a desired location inside the store.

[0016] <Example of optical system configuration for a floating image display device> Figure 2A is a diagram showing an example of the configuration of the optical system of a spatially floating image display device according to one embodiment of the present invention. The configuration of the spatially floating image display device will be explained in more detail using Figure 2A. As shown in Figure 2A(1), a display device 1 is provided that emits image light of a specific polarization at a narrow angle in the oblique direction of a transparent member 100 such as glass. The display device 1 comprises a liquid crystal display panel 11 and a light source device 13 that generates light of a specific polarization having narrow-angle diffusion characteristics.

[0017] The image light of a specific polarization from the display device 1 is reflected by a polarization separation member 101 (in the figure, the polarization separation member 101 is formed in a sheet shape and adhered to the transparent member 100) which has a film that selectively reflects the image light of the specific polarization, and is incident on the retroreflector 2. A λ / 4 plate 21 is provided on the image light incident surface of the retroreflector 2. The image light is polarized from the specific polarization to the other polarization by passing through the λ / 4 plate 21 twice, once when it is incident on the retroreflector 2 and once when it is emitted. Here, the polarization separation member 101, which selectively reflects the image light of the specific polarization, has the property of transmitting the polarization of the other polarization after polarization conversion, so the image light of the specific polarization after polarization conversion is transmitted through the polarization separation member 101. The image light that has been transmitted through the polarization separation member 101 forms a spatially floating image 3, which is a real image, on the outside of the transparent member 100. Note that in Figure 2A, the principal ray of the image light incident on the retroreflector 2 is shown as being incident at a 90° angle to the retroreflector 2. However, the incident angle of the principal ray of the image light on the retroreflector 2 is not limited to 90°; for example, 90°±15° can also be used.

[0018] Here, we will describe a first example of polarization design in the optical system shown in Figure 2A. For example, the display device 1 may be configured to emit S-polarized (S stands for senkrecht; polarization in which the electric field oscillates perpendicular to the incident plane) image light to the polarization separation member 101, and the polarization separation member 101 may be configured to reflect S-polarized light and transmit P-polarized (P stands for parallel; polarization in which the electric field oscillates within the incident plane) light. In this case, the S-polarized image light that reaches the polarization separation member 101 from the display device 1 is reflected by the polarization separation member 101 and heads towards the retroreflector 2. When the image light is reflected by the retroreflector 2, it passes through the λ / 4 plate 21 provided on the incident surface of the retroreflector 2 twice, so the image light is converted from S-polarized to P-polarized. The image light converted to P-polarized light heads towards the polarization separation member 101 again. Here, since the polarization separation member 101 has the characteristic of reflecting S-polarized light and transmitting P-polarized light, the P-polarized image light passes through the polarization separation member 101 and then through the transparent member 100. Since the image light that has passed through the transparent member 100 is light generated by the retroreflector 2, a floating image 3, which is the optical image of the display image of the display device 1, is formed at a position that is mirror-image to the display image of the display device 1 with respect to the polarization separation member 101. With such a polarization design, the floating image 3 can be suitably formed.

[0019] Next, a second example of polarization design in the optical system shown in Figure 2A will be described. For example, the display device 1 may emit P-polarized image light to the polarization separation member 101, and the polarization separation member 101 may be configured to reflect P-polarized light and transmit S-polarized light. In this case, the P-polarized image light that reaches the polarization separation member 101 from the display device 1 is reflected by the polarization separation member 101 and heads towards the retroreflector 2. When the image light is reflected by the retroreflector 2, it passes through the λ / 4 plate 21 provided on the incident surface of the retroreflector 2 twice, so the image light is converted from P-polarized to S-polarized light. The image light converted to S-polarized light heads towards the polarization separation member 101 again. Here, since the polarization separation member 101 has the characteristic of reflecting P-polarized light and transmitting S-polarized light, the S-polarized image light passes through the polarization separation member 101 and then through the transparent member 100. Since the image light transmitted through the transparent member 100 is light generated by the retroreflector 2, a floating image 3, which is an optical image of the display image of the display device 1, is formed at a position that is mirror-like to the display image of the display device 1 with respect to the polarization separation member 101. With such a polarization design, a floating image 3 can be suitably formed.

[0020] The light that forms the floating image 3 is a collection of light rays converging 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, unlike the diffused image light formed on a screen by a typical projector, the floating image 3 is an image with high directivity. Thus, in the configuration of Figure 2A, when a user views from the direction of arrow A, the floating image 3 is visible as a bright image. However, when another person views 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 systems that display images requiring high security or highly confidential images that should be hidden from people directly facing the user.

[0021] Furthermore, depending on the performance of the retroreflector 2, the polarization axis of the reflected image light may become uneven. The reflection angle may also become uneven. Such uneven light may not maintain the polarization state and propagation angle assumed in the design. For example, light with such an unintended polarization state and propagation angle may re-enter the image display side of the liquid crystal display panel 11 directly from the position of the retroreflector 2 without passing through the polarization separation member. Light with such an unintended polarization state and propagation angle may also be reflected by components within the floating image display device and then re-enter the image display side of the liquid crystal display panel 11. This re-entered light on the image display side of the liquid crystal display panel 11 may be re-reflected by the image display surface of the liquid crystal display panel 11 that constitutes the display device 1, potentially generating ghost images and degrading the image quality of the 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 absorbing polarizer 12, and the reflected light returning from the polarization separation member 101 is absorbed by the absorbing polarizer 12, thereby suppressing the above-mentioned re-reflection. This prevents image quality degradation due to ghost images of floating images in space. Specifically, if the display device 1 emits S-polarized image light to the polarization separation member 101, the absorbing polarizer 12 should be a polarizer that absorbs P-polarized light. Alternatively, if the display device 1 emits P-polarized image light to the polarization separation member 101, the absorbing polarizer 12 should be a polarizer that absorbs S-polarized light.

[0022] The polarization separation member 101 described above may be formed, for example, from a reflective polarizer or a multilayer metal film that reflects specific polarizations.

[0023] Next, Figure 2A(2) shows an example of the surface shape of a typical retroreflector 2. The retroreflector 2 has a prism body in which regularly arranged triangular pyramidal recesses serve as reflective surfaces. Light rays incident on the arranged triangular pyramidal recesses are reflected by multiple reflective surfaces of the triangular pyramidal recesses and emitted as retroreflected light in the direction corresponding to the incident light, and a floating image, which is a real image, is displayed on the display device 1.

[0024] The surface shape of the retroreflector in this embodiment is not limited to the examples described above. It may have various surface shapes that realize retroreflection. Specifically, retroreflective elements formed by periodically arranging triangular pyramidal prisms, hexagonal pyramidal prisms, other polygonal prisms, multi-vertex prisms, or combinations thereof may be provided on the surface of the retroreflector in this embodiment. Alternatively, retroreflective elements forming cube corners by periodically arranging these prisms may be provided on the surface of the retroreflector in this embodiment. These can also be expressed as corner reflector arrays or polyhedron reflector arrays. Alternatively, capsule lens type retroreflective elements formed by periodically arranging glass beads may be provided on the surface of the retroreflector in this embodiment. Since the detailed configuration of these retroreflective elements can be described using existing technology, a detailed explanation is omitted. Specifically, the technology disclosed in Japanese Patent Publication No. 2001-33609, Japanese Patent Publication No. 2001-264525, Japanese Patent Publication No. 2005-181555, Japanese Patent Publication No. 2008-70898, Japanese Patent Publication No. 2009-229942, etc., can be used.

[0025] <Another example of the optical system configuration for a spatially floating image display device 1> Another example of the optical system configuration for the floating image display device will be explained using Figure 2B. In Figure 2B, components with the same reference numerals as those in Figure 2A have the same function and configuration as those in Figure 2A. For simplicity, repeated explanations of such components will be omitted.

[0026] In the optical system shown in Figure 2B, as in Figure 2A, image light with a specific polarization is output from the display device 1. The image light with a specific polarization output from the display device 1 is input to the polarization separation member 101B. The polarization separation member 101B is a member that selectively transmits image light with a specific polarization. Unlike the polarization separation member 101 in Figure 2A, the polarization separation member 101B is not integrated with the transparent member 100, but has an independent plate-like shape. Therefore, the polarization separation member 101B may also be described as a polarization separation plate. The polarization separation member 101B may be configured as a reflective polarizer, for example, by attaching a polarization separation sheet to a transparent member. Alternatively, it may be formed by a metal multilayer film that selectively transmits the specific polarization and reflects the polarization of other specific polarizations to the transparent member. In Figure 2B, the polarization separation member 101B is configured to transmit image light with a specific polarization output from the display device 1.

[0027] 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 from one polarization to the other by passing through the λ / 4 plate 21 twice, once when it is incident on the retroreflector and once when it is emitted. Here, the polarization separation member 101B has the property of reflecting the polarization of the other polarization that has been polarized 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, forming a spatially floating image 3, which is a real image, on the outside of the transparent member 100.

[0028] Here, we will describe a first example of polarization design in the optical system shown in Figure 2B. For example, the display device 1 may emit P-polarized video light to the polarization separation member 101B, and the polarization separation member 101B may have the characteristic of reflecting S-polarized light and transmitting P-polarized light. In this case, the P-polarized video light that reaches the polarization separation member 101B from the display device 1 passes through the polarization separation member 101B and heads towards the retroreflector 2. When the video light is reflected by the retroreflector 2, it passes through the λ / 4 plate 21 provided on the incident surface of the retroreflector 2 twice, so the video light is converted from P-polarized to S-polarized light. The video light converted to S-polarized light heads towards the polarization separation member 101B again. Here, since the polarization separation member 101B has the characteristic of reflecting S-polarized light and transmitting P-polarized light, the S-polarized video light is reflected by the polarization separation member 101 and transmitted through the transparent member 100. Since the image light transmitted through the transparent member 100 is light generated by the retroreflector 2, a floating image 3, which is an optical image of the display image of the display device 1, is formed at a position that is mirror-like to the display image of the display device 1 with respect to the polarization separation member 101B. With such a polarization design, a floating image 3 can be suitably formed.

[0029] Next, a second example of polarization design in the optical system shown in Figure 2B will be described. For example, the display device 1 may be configured to emit S-polarized video light to the polarization separation member 101B, and the polarization separation member 101B may be configured to reflect P-polarized light and transmit S-polarized light. In this case, the S-polarized video light that reaches the polarization separation member 101B from the display device 1 passes through the polarization separation member 101B and heads towards the retroreflector 2. When the video light is reflected by the retroreflector 2, it passes through the λ / 4 plate 21 provided on the incident surface of the retroreflector 2 twice, so the video light is converted from S-polarized to P-polarized light. The video light converted to P-polarized light heads towards the polarization separation member 101B again. Here, since the polarization separation member 101B has the characteristic of reflecting P-polarized light and transmitting S-polarized light, the P-polarized video light is reflected by the polarization separation member 101 and transmitted through the transparent member 100. Since the image light transmitted through the transparent member 100 is light generated by the retroreflector 2, a floating image 3, which is an optical image of the display image of the display device 1, is formed at a position that is mirror-like to the display image of the display device 1 with respect to the polarization separation member 101B. With such a polarization design, the floating image 3 can be suitably formed.

[0030] In Figure 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 separation member 101B is positioned 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. As a result, in the reflection by the polarization separation member 101B, the direction of propagation of the image light reflected by the polarization separation member 101B (the direction of the principal ray of the image light) differs from the direction of propagation of the image light incident from the retroreflector 2 (the direction of the principal ray of the image light) by an angle β (e.g., 60°). With this configuration, in the optical system of Figure 2B, image light is output at a predetermined angle shown toward the outside of the transparent member 100, forming a real image of a floating image in space 3. In the configuration of Figure 2B, when a user views from the direction of arrow A, the floating image in space 3 is visible as a bright image. However, when another person views from the direction of arrow B, the floating image in space 3 cannot be seen as an image at all. This characteristic makes it ideal for systems that display video requiring high security, or highly confidential video that should be kept hidden from the user.

[0031] As explained above, the optical system in Figure 2B, although having a different configuration from the optical system in Figure 2A, can form suitable floating images in space, just like the optical system in Figure 2A.

[0032] Alternatively, an absorbing polarizer may be provided on the side of the transparent member 100 facing the polarization separation member 101B. This absorbing polarizer should transmit the polarization of the image light from the polarization separation member 101B and absorb the polarization that is 90° out of phase with the polarization of the image light from the polarization separation member 101B. In this way, the image light for forming the floating image 3 can be sufficiently transmitted, while the ambient light incident on the floating image 3 side of the transparent member 100 can be reduced by approximately 50%. This reduces stray light in the optical system shown in Figure 2B, which is caused by ambient light incident on the floating image 3 side of the transparent member 100.

[0033] <Another example of the optical system configuration for a floating image display device (2)> Another example of the optical system configuration for the floating image display device will be explained using Figure 2C. In Figure 2C, components with the same reference numerals as those in Figure 2B have the same function and configuration as those in Figure 2B. Such configurations will not be explained again for the sake of simplicity.

[0034] The only difference between the optical system in Figure 2C and the optical system in Figure 2B is the positioning angle of the polarization separation member 101B with respect 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 are 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 are omitted.

[0035] In the optical system shown in Figure 2C, the polarization separation member 101B is positioned at an angle α with respect to the image display surface of the display device 1 and the surface of the retroreflector 2. In Figure 2C, this angle α is 45°. With this configuration, in the reflection by the polarization separation member 101B, the angle β between the direction of propagation of the image light reflected by the polarization separation member 101B (the direction of the principal ray of the image light) and the direction of propagation of the image light incident from the retroreflector 2 (the direction of the principal 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 separation member 101B, thus simplifying the angular relationships of the surfaces constituting the optical system. If the surface of the transparent member 100 is positioned perpendicular to the direction of propagation of the image light reflected by the polarization separation member 101B, the angular relationships of the surfaces constituting the optical system can be further simplified. In the configuration shown in Figure 2C, when a user views the image from the direction of arrow A, the floating image 3 is visible as a bright image. However, when another person views the image from the direction of arrow B, the floating image 3 is not visible at all. This characteristic makes it ideal for systems that display highly secure images or highly confidential images that should be concealed from people directly facing the user.

[0036] As explained above, the optical system in Figure 2C, while having a different configuration from the optical systems in Figures 2A and 2B, can form suitable floating images in space, just like the optical systems in Figures 2A and 2B. Furthermore, the angles of the surfaces constituting the optical system can be made simpler.

[0037] Alternatively, an absorbing polarizer may be provided on the side of the transparent member 100 facing the polarization separation member 101B. This absorbing polarizer should transmit the polarization of the image light from the polarization separation member 101B and absorb the polarization that is 90° out of phase with the polarization of the image light from the polarization separation member 101B. In this way, the image light for forming the floating image 3 can be sufficiently transmitted, while the ambient light incident on the floating image 3 side of the transparent member 100 can be reduced by approximately 50%. This reduces stray light in the optical system of Figure 2C caused by ambient light incident on the floating image 3 side of the transparent member 100.

[0038] <Another example of the optical system configuration for a floating image display device 3> Another example of the optical system configuration for the floating image display device will be explained using Figure 2D. The optical system in Figure 2D is an optical system that uses a retroreflector 5, which is different from the retroreflector 2 used in Figures 2A to 2C. Below, another example of the optical system configuration 3 will be explained in more detail using Figures 2D to 2I. In Figure 2D, components that are denoted by the same reference numerals as in Figures 2A to 2C have the same function and configuration as those in Figures 2A to 2C. Such components will not be explained again in order to simplify the explanation.

[0039] Figure 2D shows an example of the main components and retroreflective components of a spatially floating image display device according to one embodiment of the present invention. A display device 1 that emits image light is provided obliquely to a transparent member 100 such as glass. The display device 1 comprises a liquid crystal display panel 11 and a light source device 13 that generates light.

[0040] The principal ray 9020, which represents the light beam emitted from the display device 1, travels toward the retroreflector 5 and is incident on the retroreflector 5 at an incident angle α. The incident angle α can be, for example, 45°. However, the incident angle α is not limited to 45°; for example, 45°±15° can also be used.

[0041] The retroreflector 5 is an optical component having optical properties that retroreflect light rays in at least some directions. Furthermore, since the reflected light rays have optical properties that form an image, the retroreflector 5 may also be described as an imaging optical component or imaging optical plate.

[0042] The specific configuration of the retroreflector 5 will be described in detail using Figures 2E and 2F, but the retroreflector 5 causes the principal ray 9020 to propagate in the z direction while being retroreflected in the x and y directions. As a result, the reflected ray 9021 travels away from the retroreflector 5 in an optical path that is mirror-symmetric with respect to the principal ray 9020 with respect to the retroreflector 5, passes through the transparent member 100, and forms a floating image 3 as a real image at the imaging plane.

[0043] The light beam forming the floating image 3 is a collection of light rays converging from the retroreflector 5 to the optical image of the floating image 3, and these light rays continue to travel in a straight line even after passing through the optical image of the floating image 3. Therefore, unlike diffuse images formed on a screen by general projectors, the floating image 3 is an image with high directivity. Thus, in the configuration of Figure 2, when a user views from the direction of arrow A, the floating image 3 is perceived as a bright image. However, when another person views from the direction of arrow B, the floating image 3 cannot be seen as an image at all. This characteristic is suitable for use in systems that display images requiring high security or highly confidential images that should be hidden from people directly facing the user.

[0044] An example of the configuration of the retroreflector 5 will be explained using Figures 2E and 2F. The retroreflector 5 has a configuration in which multiple corner reflectors 9040 are arranged in an array on the surface of a transparent material. This may also be called a corner reflector array or a polyhedron reflector array. The specific configuration of the corner reflectors 9040 will be described in detail using Figures 2G, 2H, and 2I, but the light rays 9111, 9112, 9113, and 9114 emitted from the light source 9110 are reflected twice by the two mirror surfaces 9041 and 9042 of the corner reflectors 9040, becoming reflected light rays 9121, 9122, 9123, and 9124. This double reflection is retroreflection in the x and y directions, where the light is reflected back in the same direction as the incident direction (moving in a direction rotated 180°), and in the z direction, it is specular reflection in which the angle of incidence and the angle of reflection coincide due to total internal reflection.

[0045] In other words, the light rays 9111 to 9114 produce reflected light rays 9121 to 9124 on a straight line symmetrical in the z direction with respect to the corner reflector 9040, forming the aerial real image 9120. The light rays 9111 to 9114 emitted from the light source 9110 are four representative rays of diffused light from the light source 9110, and depending on the diffusion characteristics of the light source 9110, the light rays incident on the retroreflector 5 are not limited to these, but any incident light ray will cause similar reflection and form the aerial real image 9120. For the sake of clarity in the diagram, the position of the light source 9110 and the position of the aerial real image 9120 in the x direction are shown offset, but in reality, the position of the light source 9110 and the position of the aerial real image 9120 in the x direction are at the same position, and when viewed from the z direction, they are in overlapping positions.

[0046] Next, the configuration and effects of the corner reflectors 9040 that constitute the retroreflector 5 will be explained in Figures 2G, 2H, and 2I. The corner reflector 9040 is a rectangular parallelepiped in which only two specific faces, 9041 and 9042, are mirrored surfaces, while the other four faces are made of a transparent material. The retroreflector 5 has a configuration in which these corner reflectors 9040 are arranged in an array such that their corresponding mirrored surfaces face the same direction.

[0047] When viewed from above (+z direction), the light ray 9111 emitted from the light source 9110 is incident on the mirror surface 9041 (or mirror surface 9042) at a specific angle of incidence, undergoes total internal reflection at the reflection point 9130, and then undergoes total internal reflection again at the reflection point 9132 on the mirror surface 9042 (or mirror surface 9041).

[0048] If the angle of incidence of ray 9111 to mirror surface 9041 (or mirror surface 9042) is θ, then the angle of incidence of the first reflected ray 9131, reflected by mirror surface 9041 (or mirror surface 9042), to mirror surface 9042 (or mirror surface 9041) can be expressed as 90°-θ. Therefore, with respect to ray 9111, the second reflected ray 9121 gains a rotation of 2θ from the first reflection and 2×(90°-θ) from the second reflection, resulting in a total reversed optical path of 180°. On the other hand, when viewed from the side (the direction midway between -x and -y), total internal reflection in the z direction occurs only once. Therefore, if the angle of incidence to mirror surface 9041 or mirror surface 9042 is φ, then with respect to ray 9111, the reflected ray 9121 gains a rotation of 2×φ from one reflection.

[0049] From the above, the light rays incident on the corner reflector 9040 undergo retroreflection with reversed optical paths in the x and y directions, and specular reflection due to total internal reflection in the z direction. Considering the retroreflector 5, similar reflections occur in each optical path, so in the x and y directions, the image is formed at a point symmetrical with respect to the z axis due to the reversing optical path with convergence properties.

[0050] In the optical system shown in Figures 2A to 2C, the retroreflector 2 has retroreflective properties in three axes. As a result, when a diffusive incident light beam is incident on the retroreflector 2, a convergent reflected light beam travels toward the side of the incident light beam where the light source is located. This convergent reflected light beam forms an image in the air, creating a floating image 3. The direction of propagation of the principal ray of the convergent reflected light beam reflected from the retroreflector 2 is opposite to the direction of propagation of the principal ray of the diffusive incident light beam incident on the retroreflector 2.

[0051] In contrast, in the optical system shown in Figure 2D, the retroreflector 5 has retroreflective properties in two axes and specular reflection in the other axis. As a result, when a diffuse incident light beam is incident on the retroreflector 5, the convergent reflected light beam reflected by the corner reflector array travels toward the retroreflector 5 toward the side of the incident light beam away from the light source. This convergent reflected light beam forms an image in the air, creating a floating image 3.

[0052] The direction of propagation of the principal ray of the convergent reflected light beam reflected by the corner reflector array of the retroreflector 5 is not in the opposite direction to the direction of propagation of the principal ray of the diffuse incident light beam incident on the retroreflector 5. The component of the direction of propagation of the principal ray of the diffuse incident light beam incident on the retroreflector 5 in the direction of the plate-shaped surface of the retroreflector 5, and the component of the direction of propagation of the principal ray after it has been reflected by the retroreflector 5 and become a convergent reflected light beam, remain in a straight line before and after reflection by the corner reflector array.

[0053] In other words, the diffusive incident light beam is converted into a convergent reflected light beam by reflection at the retroreflector 5, but in the direction normal to the plate-shaped surface of the retroreflector 5, the light beam will travel through the retroreflector 5. Here, the diffusive incident light beam that enters the retroreflector 5 and the convergent reflected light beam that exits the retroreflector 5 are geometrically symmetrical with respect to the plate-shaped surface of the retroreflector 5.

[0054] The resolution of the floating image formed by light rays from the display device 1 depends not only on the resolution of the liquid crystal display panel 11, but also largely on the diameter D and pitch P (not shown) of the retroreflective portion of the retroreflective plate 5, as shown in Figures 2E and 2F. 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 P is 300 μm, then one pixel of the floating image will be equivalent to 300 μm. As a result, the effective resolution of the floating image is reduced to about one-third.

[0055] Therefore, in order to make the resolution of the floating image in space equivalent to the resolution of the display device 1, it is desirable to bring the diameter D and pitch P of the retroreflective portion close to that of one pixel of the liquid crystal display panel. On the other hand, in order to suppress the occurrence of moiré patterns caused by the retroreflective plate and the pixels of the liquid crystal display panel, it is advisable to design the respective pitch ratios to be outside of integer multiples of one pixel. Furthermore, the shape should be arranged so that none of the sides of the retroreflective portion overlap with any of the sides of one pixel of the liquid crystal display panel.

[0056] The shape of the retroreflector (imaging optical plate) in this embodiment is not limited to the example described above. It may have various shapes that realize retroreflection. Specifically, it may be various cubic corner bodies, corner reflector arrays, slit mirror arrays, two-sided corner reflector arrays, multi-sided reflector arrays, or a shape in which combinations of their reflective surfaces are arranged periodically. Alternatively, a capsule lens type retroreflector element with glass beads arranged periodically may be provided on the surface of the retroreflector in this embodiment. The detailed configuration of these retroreflector elements can be described using existing technology, so a detailed explanation is omitted. Specifically, the technology disclosed in Japanese Patent Publication No. 2017-33005, Japanese Patent Publication No. 2019-133110, Japanese Patent Publication No. 2017-67933, WO2009 / 131128, etc., can be used.

[0057] In the optical system shown in Figure 2D, the image light emitted from the display device 1 can be in any polarization state. Both S-polarization and P-polarization are acceptable.

[0058] As explained above, the optical system in Figure 2D, while using a different retroreflective plate than the optical systems in Figures 2A to 2C, can form a more suitable floating image in space, similar to the optical systems in Figures 2A to 2C.

[0059] As described above, the optical systems shown in Figures 2A, 2B, 2C, and 2D can provide brighter, higher-quality floating images in space.

[0060] <<Block diagram of the internal structure of the floating image display device>> Next, a block diagram of the internal configuration of the floating image display device 1000 will be described. Figure 3 is a block diagram showing an example of the internal configuration of the floating image display device 1000.

[0061] The floating video display device 1000 includes a retroreflective section 1101, a video display section 1102, a light guide 1104, a light source 1105, a power supply 1106, an external power input interface 1111, an operation input section 1107, a non-volatile memory 1108, a memory 1109, a control section 1110, a video signal input section 1131, an audio signal input section 1133, a communication section 1132, an aerial operation detection sensor 1351, an aerial operation detection section 1350, an audio output section 1140, a microphone 1139, a video control section 1160, a storage section 1170, an imaging section 1180, and the like. It may also include a removable media interface 1134, an attitude sensor 1113, a transmissive self-emissive video display device 1650, a second display device 1680, or a secondary battery 1112.

[0062] Each component of the floating video display device 1000 is arranged in the housing 1190. Note that the imaging unit 1180 and the aerial operation detection sensor 1351 shown in Figure 3 may be provided on the outside of the housing 1190.

[0063] The retroreflective section 1101 in Figure 3 corresponds to the retroreflective plate 2 in Figures 2A, 2B, and 2C. The retroreflective section 1101 retroreflectively reflects light modulated by the image display section 1102. The floating image 3 is formed by the light from the reflected light from the retroreflective section 1101 that is output to the outside of the floating image display device 1000. When the optical system in Figure 2D is applied, the retroreflective section 1101 corresponds to the retroreflective plate 5 in Figure 2D.

[0064] The image display unit 1102 in Figure 3 corresponds to the liquid crystal display panel 11 in Figures 2A, 2B, and 2C. The light source 1105 in Figure 3 corresponds to the light source device 13 in Figures 2A, 2B, and 2C. The image display unit 1102, light guide 1104, and light source 1105 in Figure 3 correspond to the display device 1 in Figures 2A, 2B, and 2C.

[0065] The video display unit 1102 is a display unit that generates an image by modulating transmitted light based on a video signal input under control by the video control unit 1160, which will be described later. For example, a transmissive liquid crystal panel is used as the video display unit 1102 (the liquid crystal display panel 11 described above), but it is not limited to this. 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.

[0066] The light source 1105 generates light for the image display unit 1102 and is a solid-state light source such as an LED (Light Emitting Diode) or a laser light source. The power supply 1106 converts the AC current input from an external source via the external power input interface 1111 into DC current and supplies power to the light source 1105. The power supply 1106 also supplies the necessary DC current to each part of the floating image display device 1000. The secondary battery 1112 stores the power supplied from the power supply 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 an external source. In other words, if the floating image display device 1000 is equipped with a secondary battery 1112, the user can use the floating image display device 1000 even when power is not supplied from an external source.

[0067] The light guide 1104 guides the light generated by the light source 1105 and illuminates the image display unit 1102. The combination of the light guide 1104 and the light source 1105 can also be called the backlight of the image display unit 1102. The light guide 1104 may be mainly made of glass. The light guide 1104 may be mainly made of plastic. The light guide 1104 may be made of mirrors. Various combinations of the light guide 1104 and the light source 1105 are possible. Specific examples of combinations of the light guide 1104 and the light source 1105 will be explained in detail later.

[0068] The aerial operation detection sensor 1351 is a sensor that detects manipulation of the floating image 3 by an object such as a user's finger. The aerial operation detection sensor 1351 senses, for example, the area that overlaps with the entire display range of the floating image 3. Alternatively, the aerial operation detection sensor 1351 may sense only the area that overlaps with at least a portion of the display range of the floating image 3.

[0069] Specific examples of the aerial operation detection sensor 1351 include distance sensors using invisible light such as infrared, invisible light lasers, and ultrasonic waves. The aerial operation detection sensor 1351 may also be configured by combining multiple sensors to detect coordinates on a two-dimensional plane. Furthermore, the aerial operation detection sensor 1351 may consist of a Time of Flight (ToF) LiDAR (Light Detection and Ranging) or an image sensor.

[0070] The aerial operation detection sensor 1351 only needs to be capable of sensing touch operations by a user's finger on an object displayed as a floating spatial image 3. Such sensing can be performed using existing technologies.

[0071] The aerial operation detection unit 1350 acquires a sensing signal from the aerial operation detection sensor 1351 and, based on the sensing signal, calculates whether or not the user's finger has made contact with an object in the floating spatial image 3, and the position where the user's finger and the object made contact (contact position). The aerial operation detection unit 1350 is composed of circuits such as an FPGA (Field Programmable Gate Array). In addition, some functions of the aerial operation detection unit 1350 may be implemented in software, for example, by a spatial operation detection program executed in the control unit 1110 or the video control unit 1160. The aerial operation detection sensor 1351 and the aerial operation detection unit 1350 may be configured as an integrated unit. The aerial operation detection unit 1350 and the control unit 1110 or the video control unit 1160 may be configured as an integrated unit.

[0072] The aerial operation detection sensor 1351 and the aerial operation detection unit 1350 may be built into the floating video display device 1000, or they may be provided separately from the floating video display device 1000. When provided separately from the floating video display device 1000, the aerial operation detection sensor 1351 and the aerial operation detection unit 1350 are configured to transmit information and signals to the floating video display device 1000 via wired or wireless communication lines or video signal transmission lines. This makes it possible to construct a system in which the floating video display device 1000 without the aerial operation detection function is used as the main unit, and only the aerial operation detection function can be added as an option.

[0073] Alternatively, the aerial operation detection sensor 1351 may be a separate unit, with the aerial operation detection unit 1350 built into the floating image display device 1000. A separate unit configuration offers advantages, such as when it is desirable to have more freedom in positioning the aerial operation detection sensor 1351 relative to the installation location of the floating image display device 1000.

[0074] The imaging unit 1180 is a camera with an image sensor that captures images of the space near the floating image 3 and / or the user's face, arms, fingers, etc. Multiple imaging units 1180 may be provided. For example, the imaging units 1180 may be provided as a stereo camera. By using multiple imaging units 1180, or by using an imaging unit with a depth sensor, the aerial operation detection unit 1350 can be assisted when detecting touch operations on the floating image 3 by the user 230. The imaging unit 1180 may be provided separately from the floating image display device 1000. If the imaging unit 1180 is provided separately from the floating image display device 1000, it should be configured to transmit imaging signals to the floating image display device 1000 via a wired or wireless communication connection path.

[0075] For example, if the aerial operation detection sensor 1351 is configured as an object intrusion sensor that detects whether or not an object has entered a plane (intrusion detection plane) that includes the display surface (display range) of the floating spatial image 3, the aerial operation detection sensor 1351 may not be able to detect information such as how far away an object that has not entered the intrusion detection plane (for example, a user's finger) is from the intrusion detection plane, or how close an object is to the intrusion detection plane.

[0076] In such cases, the distance between the object and the intrusion detection plane (floating spatial image 3) can be calculated by using information such as depth calculation information based on images captured by multiple imaging units 1180 and depth information of the object from a depth sensor. This various information, including depth calculation information, depth information, and the distance between the object and the intrusion detection plane, is then used for various display controls on the floating spatial image 3.

[0077] Alternatively, instead of using the aerial operation detection sensor 1351, the aerial operation detection unit 1350 may detect touch operations on the floating video 3 by the user 230 based on the image captured by the imaging unit 1180. In this case, the imaging unit 1180 may be referred to as the aerial operation detection sensor.

[0078] Alternatively, the imaging unit 1180 may capture an image of the user operating the floating video 3, and the control unit 1110 or the like may perform user identification processing. Furthermore, in order to determine whether other people are standing around or behind the user operating the floating video 3 and whether they are peeking at the user's operation of the floating video 3, the imaging unit 1180 may capture an area that includes the user operating the floating video 3 and the area surrounding the user.

[0079] 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 signals for operations other than aerial operations (touch operations) performed by the user. Separately from the aforementioned user who touches the floating spatial image 3, the operation input unit 1107 may also be used, for example, by an administrator to operate the floating spatial image display device 1000.

[0080] The video signal input unit 1131 receives video data (video signals) by connecting an external video output device. Various digital video input interfaces can be considered for the video signal input unit 1131. For example, it can be configured with a video input interface conforming to the HDMI (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.

[0081] The audio signal input unit 1133 receives audio data (audio signals) by connecting an external audio output device. The audio signal input unit 1133 can be configured as an HDMI standard audio input interface, an optical digital terminal interface, or a coaxial digital terminal interface, etc. 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 with integrated terminals and cables.

[0082] The audio output unit 1140 is capable of outputting audio based on audio data input to the audio signal input unit 1133. The audio output unit 1140 may be configured as a speaker 1140. The audio output unit 1140 may also include a section for audio synthesis processing, etc. 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 as a digital signal to an external device, such as the Audio Return Channel function specified in the HDMI standard.

[0083] The audio input unit 1139 may be composed of a microphone 1139. The microphone 1139 is a microphone that picks up sounds from the vicinity of the floating image display device 1000, converts them into signals, and generates an audio signal. The microphone may record a person's voice, such as the user's voice, and the control unit 1110 or the like may perform speech recognition processing on the generated audio signal to obtain text information from the audio signal. The audio input unit 1139 may also be equipped with a part that performs speech recognition processing, etc. Note that the audio output unit 1140 and the audio input unit 1139, etc. may be connected as external devices to the floating image display device 1000.

[0084] The non-volatile memory 1108 stores various data used by the floating image display device 1000. The data stored in the non-volatile memory 1108 includes, for example, data for various operations displayed on the floating image 3, display icons, data and layout information for objects that the user can operate. Memory 1109 stores video data to be displayed as the floating image 3, control data for the device, and the like.

[0085] The control unit 1110 includes a processor and controls the operation of each connected part. The control unit 1110 may also work in cooperation with a program stored in the memory 1109 to perform calculation processing based on information acquired from each part of the floating image display device 1000.

[0086] 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 as, for example, an Ethernet standard LAN interface. If the communication unit 1132 has a wireless communication interface, it may be configured as, for example, 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.

[0087] Furthermore, the removable media interface 1134 is an interface for connecting removable recording media. Removable recording media may consist of semiconductor memory such as solid-state drives (SSDs), magnetic recording media recording devices such as hard disk drives (HDDs), or optical recording media such as optical discs. The removable media interface 1134 can read various types of information, such as video data, image data, and audio data, recorded on the removable recording media. Video data, image data, etc., recorded on the removable recording media are output as floating-in-space images 3 via the video display unit 1102 and the retroreflective unit 1101.

[0088] The storage unit 1170 is a storage device that records various types of information, such as video data, image data, and audio data. The storage unit 1170 may be composed of a magnetic recording medium such as a hard disk drive (HDD) or a semiconductor memory such as a solid-state drive (SSD). The storage unit 1170 may have various types of information, such as video data, image data, and audio data, pre-recorded in it at the time of product shipment. The storage unit 1170 may also record various types of information, such as video data, image data, and audio data, acquired from external devices or external servers via the communication unit 1132.

[0089] The video data, image data, etc., recorded in the storage unit 1170 are output as floating-in-space video 3 via the video display unit 1102 and the retroreflection unit 1101, based on processing by the video control unit 1160. The video data, image data, etc., of display icons and user-operable objects, etc., that are displayed as floating-in-space video 3 are also recorded in the storage unit 1170. Layout information of display icons and objects, etc., that are displayed as floating-in-space video 3, as well as various metadata information related to the objects, etc., are also recorded in the storage unit 1170.

[0090] The audio data recorded in the storage unit 1170 is output as audio from, for example, the audio output unit 1140.

[0091] The video control unit 1160 performs various controls related to the video signal input to the video display unit 1102. Based on the video signal (video data), the video control unit 1160 creates a video signal (display data) for displaying an image on the video display unit 1102 (for example, the liquid crystal display panel 11 of the aforementioned display device 1) and supplies it to the video display unit 1102. The video control unit 1160 may also be called a video processing circuit and may be composed of hardware such as an ASIC, FPGA, or video processor. The video control unit 1160 may also be called a video processing unit or image processing unit. For example, the video control unit 1160 performs video switching control, such as determining which video signal to input to the video display unit 1102 from among the video signals to be stored in the memory 1109 and the video signals (video data) input to the video signal input unit 1131.

[0092] Furthermore, the control unit 1110 may perform the same processing as the video control unit 1160, in which case the control unit 1110 may be referred to as the video processing unit, etc. At least one of the control unit 1110, the video control unit 1160, the aerial operation detection unit 1360, etc. may perform specific control processing, in which case the control unit 1110, the video control unit 1160, the aerial operation detection unit 1360, etc. may be referred to as the video processing unit.

[0093] Alternatively, 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 then input the superimposed video signal to the video display unit 1102 to form the composite image as a floating image 3.

[0094] Furthermore, the video control unit 1160 may perform image processing on video signals input from the video signal input unit 1131 and video signals stored in the memory 1109. Examples of image processing include scaling, which enlarges, reduces, and transforms images; brightness adjustment, which changes the brightness; contrast adjustment, which changes the contrast curve of an image; and retinex processing, which decomposes an image into its light components and changes the weighting of each component.

[0095] Furthermore, the video control unit 1160 may perform special effects video processing on the video signal input to the video display unit 1102 to assist the user's aerial operation (touch operation). Special effects video processing is performed, for example, based on the detection result of the user's touch operation by the aerial operation detection unit 1350 or the user's image captured by the imaging unit 1180. The video control unit 1160 may also perform audio control processing when audio is output from the audio output unit 1140 simultaneously with the floating video 3. An audio control unit for this audio control processing may be provided separately from the video control unit 1160.

[0096] The attitude sensor 1113 is a sensor composed of a gravity sensor, an acceleration sensor, or a combination thereof, and can detect the orientation in which the floating video 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 part. For example, if an undesirable orientation for the user is detected, the control unit 1110 may stop displaying the video that the video display unit 1102 was showing and display an error message to the user. Alternatively, if the attitude sensor 1113 detects that the installation orientation of the floating video display device 1000 has changed, the control unit 1110 may rotate the orientation of the video that the video display unit 1102 was showing.

[0097] As explained above, the floating image display device 1000 is equipped with various functions. However, the floating image display device 1000 does not need to have all of these functions; any configuration is acceptable as long as it has the function of forming the floating image 3.

[0098] <Example configuration of a floating image display device> Next, we will describe an example configuration of the floating image display device. The layout of the components of the floating image display device according to this embodiment can vary depending on the usage. Below, we will describe each of the layouts shown in Figures 4A to 4P. In all of the examples in Figures 4A to 4P, the thick lines surrounding the components of the floating image display device 1000 (display device 1, etc.) indicate an example of the housing structure of the floating image display device 1000 (housing 1190 in Figure 3).

[0099] Figure 4A shows an example of the configuration of a floating image display device. The floating image display device 1000 shown in Figure 4A is equipped with an optical system corresponding to the optical system in Figure 2A. In the floating image display device 1000 shown in Figure 4A, it is installed horizontally so that the side on which the floating image 3 is formed faces upward. That is, in Figure 4A, the floating image display device 1000 has a transparent member 100 installed on the top surface of the device. The floating image 3 is formed above the surface of the transparent member 100 of the floating image display device 1000. The light of the floating image 3 travels diagonally upward. If the air operation detection sensor 1351 is installed as shown in the figure, it is possible to detect operation of the floating image 3 by the user 230's finger. Note that the x direction is the left-right direction from the user's perspective, the y direction is the front-back direction (depth direction) from the user's perspective, and the z direction is the up-down direction (vertical direction). In the following diagrams in Figure 4, the definitions of the x, y, and z directions are the same, so repeated explanations will be omitted.

[0100] Figure 4B shows an example of the configuration of a floating image display device. The floating image display device 1000 shown in Figure 4B is equipped with an optical system corresponding to the optical system in Figure 2A. The floating image display device 1000 shown in Figure 4B is installed vertically so that the side on which the floating image 3 is formed faces the front of the floating image display device 1000 (towards the user 230). That is, in Figure 4B, the floating image display device has a transparent member 100 installed on the front of the device (towards the user 230). The floating image 3 is formed on the user 230 side relative to the surface of the transparent member 100 of the floating image display device 1000. The light of the floating image 3 travels diagonally upward. If the aerial operation detection sensor 1351 is provided as shown in the figure, it is possible to detect operation of the floating image 3 by the user 230's finger. As shown in Figure 4B, the airborne operation detection sensor 1351 senses the user's finger from above, allowing it to utilize the reflection of sensing light from the user's fingernail for touch detection. Generally, fingernails have a higher reflectivity than the pads of the fingers, so this configuration can improve the accuracy of touch detection.

[0101] Figure 4C shows an example of the configuration of a floating image display device. The floating image display device 1000 shown in Figure 4C is equipped with an optical system corresponding to the optical system in Figure 2B. In the floating image display device 1000 shown in Figure 4C, it is installed horizontally so that the side on which the floating image 3 is formed faces upward. That is, in Figure 4C, the floating image display device 1000 has a transparent member 100 installed on the top surface of the device. The floating image 3 is formed above the surface of the transparent member 100 of the floating image display device 1000. The light of the floating image 3 travels diagonally upward. If the aerial operation detection sensor 1351 is provided as shown in the figure, it is possible to detect operation of the floating image 3 by the user 230's finger.

[0102] Figure 4D shows an example of the configuration of a floating image display device. The floating image display device 1000 shown in Figure 4D is equipped with an optical system corresponding to the optical system in Figure 2B. The floating image display device 1000 shown in Figure 4D is installed vertically so that the side on which the floating image 3 is formed faces the front of the floating image display device 1000 (towards the user 230). That is, in Figure 4D, the floating image display device 1000 has a transparent member 100 installed on the front of the device (towards the user 230). The floating image 3 is formed on the user 230 side of the transparent member 100 of the floating image display device 1000. The light of the floating image 3 travels diagonally upward. If the aerial operation detection sensor 1351 is provided as shown in the figure, it is possible to detect operation of the floating image 3 by the user 230's finger. Here, as shown in Figure 4D, the airborne operation detection sensor 1351 senses the user's finger from above, and the reflection of the sensing light from the user's fingernail can be used for touch detection. Generally, fingernails have a higher reflectivity than the pads of the fingers, so this configuration can improve the accuracy of touch detection.

[0103] Figure 4E shows an example of the configuration of a floating image display device. The floating image display device 1000 shown in Figure 4E is equipped with an optical system corresponding to the optical system in Figure 2C. In the floating image display device 1000 shown in Figure 4E, it is installed horizontally so that the side on which the floating image 3 is formed faces upward. That is, in Figure 4E, the floating image display device 1000 has a transparent member 100 installed on the top surface of the device. The floating image 3 is formed above the surface of the transparent member 100 of the floating image display device 1000. The light of the floating image 3 travels in a direction directly upward. If the air operation detection sensor 1351 is provided as shown in the figure, it is possible to detect operation of the floating image 3 by the user 230's finger.

[0104] Figure 4F shows an example of the configuration of a floating image display device. The floating image display device 1000 shown in Figure 4F is equipped with an optical system corresponding to the optical system in Figure 2C. The floating image display device 1000 shown in Figure 4F is installed vertically so that the side on which the floating image 3 is formed faces the front of the floating image display device 1000 (towards the user 230). That is, in Figure 4F, the floating image display device 1000 has a transparent member 100 installed on the front of the device (towards the user 230). The floating image 3 is formed on the user 230 side relative to the surface of the transparent member 100 of the floating image display device 1000. The light of the floating image 3 travels in the direction toward the user. If the aerial operation detection sensor 1351 is provided as shown in the figure, it is possible to detect operation of the floating image 3 by the user 230's finger.

[0105] Figure 4G shows an example of the configuration of a floating image display device. The floating image display device 1000 shown in Figure 4G is equipped with an optical system corresponding to the optical system in Figure 2C. In the optical systems of the floating image display devices shown in Figures 4A to 4F, the optical path of the center of the image light emitted from the display device 1 was on the yz plane. That is, within the optical systems of the floating image display devices shown in Figures 4A to 4F, the image light traveled in the front-to-back and up-and-down directions as viewed from the user. In contrast, in the optical system of the floating image display device shown in Figure 4G, the optical path of the center of the image light emitted from the display device 1 is on the xy plane. That is, within the optical system of the floating image display device shown in Figure 4G, the image light travels in the left-to-right and front-to-back directions as viewed from the user. In the floating image display device 1000 shown in Figure 4G, the side on which the floating image 3 is formed is installed so that it faces the front of the device (towards the user 230). In other words, in Figure 4G, the floating image display device 1000 has a transparent member 100 installed on the front of the device (towards the user 230). The floating image 3 is formed on the user side relative to the surface of the transparent member 100 of the floating image display device 1000. The light of the floating image 3 travels toward the user. If the aerial operation detection sensor 1351 is provided as shown in the figure, it is possible to detect operation of the floating image 3 by the user 230's finger.

[0106] Figure 4H shows an example of the configuration of a floating image display device. The floating image display device 1000 in Figure 4H differs from the floating image display device in Figure 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 from which the user 230 views the floating image 3, i.e., opposite the direction of propagation of the image light of the floating image 3 directed toward the user 230). The other configurations are the same as those of the floating image display device in Figure 4G, so repeated explanations are omitted. The floating image display device 1000 in Figure 4H has a window with a transparent plate 100B at a position opposite to the direction of propagation of the image light of the floating image 3. Therefore, when the user 230 views the floating image 3, they can recognize the scenery behind the floating image display device 1000 as the background of the floating image 3. Therefore, the user 230 can perceive the floating image 3 as floating in the air in front of the scenery behind the floating image display device 1000. This further enhances the sense of floating in the air of the floating image 3.

[0107] Depending on the polarization distribution of the video light output from the display device 1 and the performance of the polarization separation member 101B, some of the video light output from the display device 1 may be reflected by the polarization separation member 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 seen by the user 230 as stray light. Therefore, in order to prevent such stray light, the transparent plate 100B may not be provided in the window on the back of the floating video display device 1000.

[0108] Figure 4I shows an example of the configuration of a floating image display device. The floating image display device 1000 in Figure 4I differs from the floating image display device in Figure 4H in that it has an opening / closing door 1410 for light shielding on the window of the transparent plate 100B located on the back of the device (opposite the position from which the user 230 views the floating image 3). The other configurations are the same as those of the floating image display device in Figure 4H, so repeated explanations are omitted.

[0109] The opening and closing door 1410 of the floating spatial image display device 1000 in Figure 4I has, for example, a light-shielding plate and is equipped with a mechanism for moving (sliding), rotating, or attaching / detaching the light-shielding plate, thereby enabling switching between an open state and a light-shielding state for the window (rear window) of the transparent plate 100B located at the back of the floating spatial image display device 1000. The movement (sliding) and rotation of the light-shielding plate by the opening and closing door 1410 may be electrically driven by a motor (not shown). This motor may be controlled by the control unit 1110 in Figure 3. Note that in the example in Figure 4I, an example is disclosed in which the opening and closing door 1410 has two light-shielding plates. However, the opening and closing door 1410 may have only one light-shielding plate.

[0110] For example, if the view beyond the window of the transparent panel 100B of the floating image display device 1000 is outdoors, the brightness of sunlight will vary depending on the weather. If the sunlight outdoors is strong, the background of the floating image 3 may become too bright, reducing the visibility of the floating image 3 for the user 230. In such cases, by moving (sliding), rotating, or attaching the light-shielding plate of the opening / closing door 1410 to block the light on the rear window, the background of the floating image 3 will become darker, thereby relatively improving the visibility of the floating image 3. This shielding operation by the light-shielding plate of the opening / closing door 1410 may be performed directly by the force of the user 230's hand. Alternatively, the control unit 1110 may control a motor (not shown) in response to an operation input via the operation input unit 1107 in Figure 3 to perform the shielding operation by the light-shielding plate of the opening / closing door 1410.

[0111] Furthermore, an illuminance sensor may be installed on the rear side of the floating spatial image display device 1000 (opposite side of the user 230), 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 Figure 3 may control a motor (not shown) to open and close the light-shielding plate of the opening / closing door 1410 according to the detection result of the illuminance sensor. By controlling the opening and closing operation of the light-shielding plate of the opening / closing door 1410 in this way, the visibility of the floating spatial image 3 can be more favorably maintained without the user 230 having to manually open or close the light-shielding plate of the opening / closing door 1410.

[0112] Furthermore, the light-shielding plate provided by the opening / closing door 1410 may be manually detachable. Depending on the intended use and installation environment of the spatial floating image display device 1000, the user can choose whether to leave the rear window open or detached. If the rear window is to be used in a detached state for a long period of time, the detachable light-shielding plate can be fixed in the detached state. If the rear window is to be used in an open state for a long period of time, the detachable light-shielding plate can be removed. The light-shielding plate may be attached and detached using screws, a hook structure, or a snap-in structure.

[0113] In the example of the floating video display device 1000 shown in Figure 4I, depending on the polarization distribution of the video light output from the display device 1 and the performance of the polarization separation member 101B, some of the video light output from the display device 1 may be reflected by the polarization separation member 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 seen by the user 230 as stray light. Therefore, in order to prevent such stray light, the window on the back of the floating video display device 1000 may be configured without the transparent plate 100B. The window without the transparent plate 100B may be provided with the above-mentioned opening and closing door 1410. In order to prevent such stray light, it is desirable that the inner surface of the housing of the light-shielding plate of the above-mentioned opening and closing door 1410 has a coating or material with low light reflectivity.

[0114] Figure 4J shows an example of the configuration of a floating image display device. The floating image display device 1000 in Figure 4J differs from the floating image display device 1000 in Figure 4H in that instead of placing a transparent plate 100B made of glass or plastic in the rear window, an electronically controlled variable transmittance device 1620 is placed therein. The other configurations are the same as those of the floating image display device in Figure 4H, so repeated explanations are omitted. An example of the electronically controlled variable transmittance device 1620 is a liquid crystal shutter. Although the electronically controlled variable transmittance device 1620 is not shown in Figure 3, if it is to be provided, it should be configured as a component of the floating image display device 1000 in Figure 3 and connected to other processing units such as the control unit 1110.

[0115] A liquid crystal shutter can control the light transmittance 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 floating image 3 will be the scenery visible through the rear window. Conversely, by controlling the liquid crystal shutter to decrease the transmittance, the scenery visible through the rear window will not be visible as the background of the floating image 3.

[0116] Furthermore, since the liquid crystal shutter allows for control of intermediate tones, it can be set to a state such as 50% transmittance. For example, the control unit 1110 can control the transmittance of the electronically controlled variable transmittance device 1620 in response to an operation input via the operation input unit 1107 in Figure 3. With this configuration, if the view through the rear window is desired as the background for the floating image 3, but the view through the rear window is too bright, reducing the visibility of the floating image 3, the visibility of the floating image 3 can be adjusted by adjusting the transmittance of the electronically controlled variable transmittance device 1620.

[0117] Alternatively, an illuminance sensor may be installed on the rear side of the floating image display device 1000 (opposite the user 230), 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 Figure 3 can control the transmittance of the electronically controlled variable transmittance device 1620 according to the detection result of the illuminance sensor. In this way, the transmittance of the electronically controlled variable transmittance device 1620 can be adjusted according to the brightness of the space beyond the rear window without the user 230 having to perform an operation input via the operation input unit 1107 in Figure 3, thereby making it possible to maintain the visibility of the floating image 3 more favorably.

[0118] Furthermore, in the above example, a liquid crystal shutter was described as an example of the electronically controlled variable transmittance device 1620. In contrast, electronic paper may be used as another example of the electronically controlled variable transmittance device 1620. The same effects as described above can be obtained even when electronic paper is used. Moreover, electronic paper consumes very little power to maintain the halftone state. Therefore, a spatial levitation image display device with lower power consumption can be realized compared to the case in which a liquid crystal shutter is used.

[0119] Figure 4K shows an example of the configuration of a floating image display device. The floating image display device 1000 in Figure 4K differs from the floating image display device in Figure 4G in that it has a transmissive self-emissive image display device 1650 instead of a transparent member 100. The other configurations are the same as those of the floating image display device in Figure 4G, so repeated explanations are omitted.

[0120] In the spatial levitation image display device 1000 shown in Figure 4K, the spatial levitation image 3 is formed outside the spatial levitation image display device 1000 after the image light beam passes through the display surface of the transmissive self-emissive image display device 1650. That is, when an image is displayed on the transmissive self-emissive image display device 1650, which is a two-dimensional planar display, the spatial levitation image 3 can be displayed as a projecting image further in front of the user than the image on the transmissive self-emissive image display device 1650. At this time, the user 230 can simultaneously view two images at different depth positions. The transmissive self-emissive image display device 1650 can be constructed using existing technologies such as transmissive organic EL panels, as disclosed in, for example, Japanese Patent Application Publication No. 2014-216761. When the transmissive self-emissive image display device 1650 is provided, it can be configured to be connected to other processing units such as the control unit 1110 as one component of the spatial levitation image display device 1000 shown in Figure 3.

[0121] Here, if the transparent self-emissive video display device 1650 displays both the background and objects such as characters, and then displays only the objects such as characters moving to the floating video 3 in the foreground, the user 230 can be provided with a more effective surprise video experience.

[0122] Furthermore, if the inside of the floating image display device 1000 (housing 1190) is kept in a light-shielding state, the background of the transmissive self-emissive image display device 1650 becomes sufficiently dark. Therefore, when no image is displayed on the display device 1, or when the light source of the display device 1 is turned off and an image is displayed only on the transmissive self-emissive image display device 1650, the user 230 will perceive the transmissive self-emissive image display device 1650 as a normal two-dimensional planar display rather than a transmissive display. In this embodiment of the present invention, the floating image 3 is displayed as a real optical image in space without a screen, so if the light source of the display device 1 is turned off, the planned display location for the floating image 3 becomes empty space. Therefore, when the transmissive self-emissive image display device 1650 is being used as if it were a general two-dimensional planar display to show an image, characters or objects can be suddenly displayed in mid-air as the floating image 3, providing the user 230 with a more effective surprise visual experience.

[0123] Furthermore, the darker the interior of the floating image display device 1000 is made, the more the transmissive self-emissive image display device 1650 appears like a two-dimensional planar display. Therefore, an absorbing polarizing plate (not shown) that transmits the polarization of the image light reflected by the polarization separation member 101B and absorbs polarization that is 90° out of phase with that polarization may be provided on the interior side of the transmissive self-emissive image display device 1650 (the incident surface for the image light reflected by the polarization separation member 101B into the transmissive self-emissive image display device 1650, i.e., the side of the transmissive self-emissive image display device 1650 opposite to the floating image 3). In this way, the impact on the image light forming the floating image 3 is not so great, but the amount of light incident on the interior of the floating image display device 1000 from the outside via the transmissive self-emissive image display device 1650 can be significantly reduced, making the interior of the floating image display device 1000 darker, which is preferable.

[0124] Figure 4L shows an example of the configuration of a floating image display device. The floating image display device 1000 in Figure 4L is a modified version of the floating image display device in Figure 4K. The orientation of the components in the floating image display device 1000 differs from that of the floating image display device in Figure 4K, and is closer to that of the floating image display device in Figure 4F. The functions and operations of each component are the same as those of the floating image display device in Figure 4K, so repeated explanations are omitted.

[0125] In the floating image display device shown in Figure 4L, after the light beam of the image passes through the transmissive self-emissive image display device 1650, the floating image 3 is formed on the user 230 side of the transmissive self-emissive image display device 1650.

[0126] In both the example of the floating image display device in Figure 4K and the example of the floating image display device in Figure 4L, the floating image 3 is displayed superimposed in front of the image on the transmissive self-emissive image display device 1650 to the user 230. Here, the position of the floating image 3 and the position of the image on the transmissive self-emissive image display device 1650 are configured to have a difference in the depth direction. Therefore, when the user 230 moves their head (viewpoint position), they can perceive the depth of the two images due to parallax. Thus, by displaying two images with different depth positions, a three-dimensional image experience can be more favorably provided to the user with the naked eye, without the need for stereoscopic glasses or other such devices.

[0127] Figure 4M shows an example of the configuration of a floating image display device. In the floating image display device 1000 of Figure 4M, a second display device 1680 is provided on the rear side (for example, the back panel of the housing 1190) from the user 230's perspective, relative to the polarization separation member 101B of the floating image display device in Figure 4G. The other configurations are the same as those of the floating image display device in Figure 4G, so repeated explanations are omitted.

[0128] In the configuration example shown in Figure 4M, the second display device 1680 is located behind the display position of the floating image 3, with its display surface facing the floating image 3. With this configuration, the user 230 can view the image from the second display device 1680 and the floating image 3, which are displayed at two different depths, superimposed on each other. In other words, the second display device 1680 is positioned to display the image in the direction of the user 230 who is viewing the floating image 3. When providing the second display device 1680, it can be configured as a component of the floating image display device 1000 in Figure 3, and connected to other processing units such as the control unit 1110.

[0129] In Figure 4M, the video light from the second display device 1680 of the floating video display device 1000 is seen by the user 230 after passing through the polarization separation member 101B. Therefore, in order for the video light from the second display device 1680 to pass through the polarization separation member 101B more favorably, it is desirable that the video light output from the second display device 1680 has polarization in the direction of vibration that the polarization separation member 101B passes through more favorably. That is, it is desirable that the polarization is in the same direction of vibration as the video light output from the display device 1. For example, if the video light output from the display device 1 is S-polarized, it is desirable that the video light output from the second display device 1680 is also S-polarized. Also, if the video light output from the display device 1 is P-polarized, it is desirable that the video light output from the second display device 1680 is also P-polarized.

[0130] The example of the floating image display device in Figure 4M has the same effect as the examples of the floating image display devices in Figure 4K and Figure 4L, in that it displays a second image behind the floating image 3. However, unlike the examples of the floating image display devices in Figure 4K and Figure 4L, in the example of the floating image display device in Figure 4M, the light beam of the image light that forms the 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-emissive image display device, and can be a liquid crystal display, which is a two-dimensional planar display. The second display device 1680 can also be an organic EL display. Therefore, in the example of the floating image display device in Figure 4M, it is possible to realize the floating image display device 1000 at a lower cost than in the examples of the floating image display devices in Figure 4K and Figure 4L.

[0131] Here, depending on the polarization distribution of the video light output from the display device 1 and the performance of the polarization separation member 101B, a portion of the video light output from the display device 1 may be reflected by the polarization separation member 101B and directed toward the second display device 1680. This light (a portion of the video light) may be reflected again by the surface of the second display device 1680 and may be visible to the user as stray light.

[0132] Therefore, in order to prevent stray light, an absorbing polarizer may be provided on the surface of the second display device 1680. In this case, the absorbing polarizer should be one that transmits the polarization of the image light output from the second display device 1680 and absorbs polarization that is 90° out of phase with the polarization of the image light output from the second display device 1680. If the second display device 1680 is a liquid crystal display, an absorbing polarizer also exists on the image output side inside 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 absorbing polarizer on the image output side inside the liquid crystal display, it is not possible to prevent stray light caused by reflection from the cover glass due to light from outside the liquid crystal display. Therefore, it is necessary to separately provide the above-mentioned absorbing polarizer on the surface of the cover glass.

[0133] Furthermore, when displaying an image on the second display device 1680, which is a two-dimensional planar display, the floating spatial image 3 can be displayed as an image further in front of the user than the image on the second display device 1680. In this case, the user 230 can simultaneously view two images with different depth positions. By displaying a character on the floating spatial image 3 and a background on the second display device 1680, it is possible to provide the user 230 with the effect of viewing the space in which the character exists in three dimensions.

[0134] Furthermore, by displaying both the background and objects such as characters on the second display device 1680, and then displaying the objects such as characters moving to the foreground floating image 3, it is possible to provide the user 230 with a more effective surprise-style video experience.

[0135] Next, Figure 4N shows an example of the configuration of a floating image display device. The floating image display device 1000 in Figure 4N is a floating image display device that employs the optical system shown in Figure 2D. Similar to the examples of floating image display devices employing the optical systems in Figures 2A to 2C, the floating image display device 1000 in Figure 4N projects the image light that has passed through the transparent member 100 into the air as a floating image 3. Furthermore, the sensing light from the air operation detection sensor 1351, which is positioned behind the transparent member 100 as seen from the user's perspective, can be used to detect the user's finger 9004 operating the floating image 3.

[0136] In both the example of a floating image display device employing the optical system shown in Figures 2A to 2C, and the example of a floating image display device employing the optical system shown in Figure 2D, the floating image 3 is projected in front of the transparent member 100, and the user's finger movements of the floating image 3 can be detected using the sensing light of the aerial operation detection sensor 1351, which is positioned behind the transparent member 100 from the user's perspective.

[0137] The floating image display device employing the optical system shown in Figure 2D has a different optical system from the floating image display devices employing the optical systems shown in Figures 2A to 2C, which are located behind the transparent component 100 as seen from the user's perspective. However, the usability of the floating image display device employing the optical system shown in Figure 2D as seen from the user's perspective is almost the same as that of the floating image display devices employing the optical systems shown in Figures 2A to 2C.

[0138] Next, Figure 4O is a diagram showing an example of the configuration of a floating image display device. Figure 4O is a diagram that shows the configuration of the internal optical system in the floating image display device 1000 of Figure 4N. The floating image display device 1000 shown in Figure 4O is equipped with an optical system corresponding to the optical system in Figure 2D. In the floating image display device 1000 shown in Figure 4O, it is installed horizontally so that the side on which the floating image 3 is formed faces upward.

[0139] In other words, in Figure 4O, the floating image display device 1000 has a transparent member 100 installed on its upper surface. The floating image 3 is formed above the surface of the transparent member 100 of the floating image display device 1000. The light of the floating image 3 travels diagonally upward. If the aerial operation detection sensor 1351 is provided as shown in the figure, it is possible to detect operation of the floating image 3 by the user 230's finger.

[0140] Here, we compare the configuration of Figure 4O with the configuration of Figure 4A and confirm the differences. In Figure 4A, the display device 1 and the floating image 3 are symmetrical with respect to the plane of the polarization separation member 101. In contrast, in Figure 4O, the display device 1 and the floating image 3 are symmetrical with respect to the plane of the retroreflector 5. Also, the configuration of Figure 4A includes a retroreflector 2 and a λ / 4 plate 21, but these are not present in Figure 4O. Furthermore, in Figure 4A, it is preferable to have an absorptive polarizer 12, but in Figure 4O, an absorptive polarizer 12 is not particularly necessary.

[0141] To replace the optical system of Figure 2A in the configuration of Figure 4A with the optical system of Figure 2D and to replace it with the configuration of Figure 4O, the following should be done. That is, the polarization separation member 101 in the configuration of Figure 4A should be replaced with the retroreflector 5, and the retroreflector 2 and λ / 4 plate 21 should be removed from the configuration of Figure 4A. The absorbing polarizer 12 may or may not be included. By performing substitutions based on this idea, the optical systems of Figures 2A to 2C mounted on the spatial floating image display device configurations of Figures 4A to 4G can be replaced with the optical system of Figure 2D, and the spatial floating image display device can be replaced with the optical system of Figure 2D. In this case, in Figures 4A and 4B, the polarization separation member 101 should be replaced with the retroreflector 5, and in Figures 4C to 4G, the polarization separation member 101B should be replaced with the retroreflector 5.

[0142] For example, Figure 4P is a diagram showing an example of the configuration of a floating image display device. The floating image display device 1000 shown in Figure 4P is equipped with an optical system corresponding to the optical system in Figure 2D. Figure 4P is a configuration of the floating image display device in Figure 4B in which the optical system in Figure 2A is replaced with the optical system in Figure 2D. The floating image display device 1000 shown in Figure 4P is installed vertically so that the side on which the floating image 3 is formed faces the front of the floating image display device 1000 (towards the user 230). That is, in Figure 4P, the floating image display device has a transparent member 100 installed on the front of the device (towards the user 230). The floating image 3 is formed on the user 230 side relative to the surface of the transparent member 100 of the floating image display device 1000. The light of the floating image 3 travels diagonally upward. If the air operation detection sensor 1351 is provided as shown in the figure, it is possible to detect operation of the floating image 3 by the user 230's finger. As shown in Figure 4P, the airborne operation detection sensor 1351 senses the user's finger from above, allowing it to utilize the reflection of sensing light from the user's fingernail for touch detection. Generally, fingernails have a higher reflectivity than the pads of the fingers, so this configuration can improve the accuracy of touch detection.

[0143] According to the configuration of the floating image display device shown in Figures 4N to 4P, a user-friendly floating image display device can be realized using the optical system shown in Figure 2D.

[0144] <Display device> Next, the display device 1 of this embodiment will be described with reference to the figures. The display device 1 of this embodiment includes a liquid crystal display panel 11, which is an image display element 11, and a light source device 13 that constitutes the light source of the liquid crystal display panel 11. In Figure 5, the light source device 13 is shown together with the liquid crystal display panel 11 in an unfolded perspective view.

[0145] The liquid crystal display panel 11, which is the image display element 11, receives an illumination beam from the light source device 13, which is the backlight device, as shown by the arrow 30 in Figure 5. The illumination beam has narrow-angle diffusion characteristics, that is, it has strong directionality (in other words, straight-line propagation) and characteristics similar to laser light with the polarization plane aligned in one direction. The liquid crystal display panel 11, which is the image display element 11, modulates the received illumination beam according to the input video signal. The modulated video light is reflected by the retroreflector 2 and transmitted through the transparent member 100 to form a floating image in space, which is a real image (see Figure 1).

[0146] Furthermore, in Figure 5, the display device 1 is configured to include a light source device 13 and a liquid crystal display panel 11, as well as an optical direction conversion 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. That is, polarizing plates are provided on both sides of the liquid crystal display panel 11, and as shown by the arrow 30 in Figure 5, the configuration is such that image light of a specific polarization is emitted after the intensity of the light is modulated by the image signal. As a result, the desired image is projected as light of a specific polarization with high directionality (straight-line propagation) via the optical direction conversion panel 54 toward the retroreflector 2, reflected by the retroreflector 2, and then transmitted toward the eyes of a monitor outside the store (space) in Figure 1 to form a floating image 3 in space. Note that a protective cover 50 (see Figures 6 and 7) may be provided on the surface of the optical direction conversion panel 54 described above.

[0147] <Example of a display device 1> Figure 6 shows an example of the specific configuration of the display device 1. In Figure 6, a liquid crystal display panel 11 and a light direction conversion panel 54 are arranged on top of the light source device 13 shown in Figure 5. This light source device 13 is constructed by housing LED elements 201 and a light guide 203 inside, for example, a plastic case. As shown in Figure 5, the end face of the light guide 203 has a lens shape that gradually increases in cross-sectional area toward the light receiving part, and has the effect of gradually decreasing the divergence angle by undergoing multiple total internal reflections as the light propagates through the interior, in order to convert the divergent light emitted from each LED element 201 into a substantially parallel luminous beam. The liquid crystal display panel 11 that constitutes the display device 1 is mounted on the top surface of the display device 1. In addition, an LED substrate 202 on which semiconductor light sources, namely LED elements 201 and their control circuits are mounted is attached to one side of the light source device 13 (the left end face in this example). A heat sink, which is a component for cooling the heat generated by the LED elements 201 and the control circuits, may be attached to the outer surface of the LED substrate 202.

[0148] Furthermore, the frame (not shown) of the liquid crystal display panel 11, which is mounted on the top surface of the case of the light source device 13, is configured by mounting the liquid crystal display panel 11 attached to the frame, and also by mounting an FPC (Flexible Printed Circuits) (not shown) electrically connected to the liquid crystal display panel 11. In other words, the liquid crystal display panel 11, which is the image display element 11, generates a display image by modulating the intensity of transmitted light based on a control signal from a control circuit (image control unit 1160 in Figure 3) that constitutes the electronic device, together with the LED element 201, which is the solid light source. At this time, the generated image light has a narrow diffusion angle and consists only of specific polarization components, so a new and unprecedented image display device is obtained that is similar to a surface-emitting laser image source driven by an image signal. Currently, it is technically and safely impossible to obtain a laser beam of the same size as the image obtained by the above-described display device 1 using a laser device. Therefore, in this embodiment, for example, light similar to the surface-emitting laser image light described above is obtained from a light beam from a general light source equipped with an LED element.

[0149] Next, the configuration of the optical system housed within the case of the light source device 13 will be described in detail with reference to Figure 6 and Figure 7. Since Figures 6 and 7 are cross-sectional views, only one of the multiple LED elements 201 constituting the light source is shown, and these are converted into approximately parallel light (collimated light) by the shape of the light-receiving end face 203a of the light guide 203. For this reason, the light-receiving portion of the end face of the light guide and the LED element 201 are mounted while maintaining a predetermined positional relationship.

[0150] Each of these light guides 203 is formed from a translucent resin such as acrylic. The LED light-receiving surface at the end of the light guide 203 has, for example, a cone-shaped outer surface obtained by rotating a parabolic cross-section, with a recess at its apex that forms a convex portion (i.e., a convex lens surface) in its center, and a convex lens surface (or a concave lens surface that is recessed inward) in the center of its flat portion (not shown). The outer shape of the light-receiving portion of the light guide to which the LED element 201 is attached is a parabolic shape that forms a cone-shaped outer surface, and is set within an angle range that allows for total internal reflection of light emitted from the LED element in the peripheral direction, or a reflective surface is formed.

[0151] On the other hand, the LED elements 201 are each positioned at predetermined locations on the surface of the LED substrate 202, which is their circuit board. The LED substrate 202 is fixed to the light-receiving end face 203a, which is an LED collimator, with the LED elements 201 on its surface positioned in the center of the aforementioned recesses.

[0152] With this configuration, the shape of the light-receiving end face 203a of the light guide 203 makes it possible to extract the light emitted from the LED element 201 as substantially parallel light, thereby improving the utilization efficiency of the generated light.

[0153] As described above, the light source device 13 is configured by attaching a light source unit, which consists of multiple LED elements 201 arranged in a row, to a light-receiving end surface 203a, which is a light-receiving part provided on the end face of a light guide 203. The divergent light beam from the LED elements 201 is guided through the inside of the light guide 203 as substantially parallel light by the lens shape of the light-receiving end surface 203a of the light guide 203, as indicated by the arrows, and is emitted toward the liquid crystal display panel 11, which is arranged substantially parallel to the light guide 203, by the light beam direction conversion means 204. By optimizing the distribution (in other words, density) of this light beam direction conversion means 204 depending on the shape of the inside or surface of the light guide 203, the uniformity of the light beam incident on the liquid crystal display panel 11 can be controlled.

[0154] The aforementioned light beam direction conversion means 204, by the shape of the surface of the light guide 203, or by providing, for example, a portion with a different refractive index inside the light guide 203, emits the light beam propagating within the light guide 203 toward the liquid crystal display panel 11, which is arranged substantially parallel to the light guide 203. At this time, if the liquid crystal display panel 11 is facing the center of the screen and the viewpoint is placed at the same position as the screen diagonal, and the relative brightness ratio of the screen center and the screen periphery is 20% or more, there is no practical problem, and if it exceeds 30%, it is an even better characteristic.

[0155] Figure 6 is a cross-sectional diagram illustrating the configuration and operation of the light source in this embodiment, which performs polarization conversion in the light source device 13 including the light guide 203 and LED element 201 described above. In Figure 6, the light source device 13 consists of a light guide 203 with a light beam direction conversion means 204 provided on its surface or inside, which is formed of, for example, plastic; an LED element 201 as a light source; a reflective sheet 205; a phase difference plate 206; a lenticular lens, etc. A liquid crystal display panel 11 equipped with polarizing plates on the light source light incident surface and the image light output surface is mounted on the upper surface of the light source device 13.

[0156] Furthermore, a film or sheet-like reflective polarizer 49 is provided on the light source light incident surface (lower surface in the figure) of the liquid crystal display panel 11 corresponding to the light source device 13, selectively reflecting one side of the 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 side (lower surface in the figure) of the light guide 203 and directed towards the liquid crystal display panel 11. Therefore, a phase difference 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 polarizer 49. The reflected light (reflected light beam) is reflected by the reflective sheet 205 and passes through the phase difference plate (λ / 4 plate) a total of two times, converting it from P-polarized to S-polarized. This improves the efficiency of utilizing the light source as image light. The image light beam, whose light intensity has been modulated by the video signal on the liquid crystal display panel 11, is emitted as shown by arrow 213 in Figure 6 and incident on the retroreflector 2. After reflection by the retroreflector 2, a real image, a floating image in space, can be obtained.

[0157] Figure 7, similar to Figure 6, is a cross-sectional arrangement diagram illustrating the configuration and operation of the light source in this embodiment, which performs polarization conversion in a light source device 13 including a light guide 203 and an LED element 201. The light source device 13 is similarly composed of a light guide 203 with a light beam direction conversion means 204 provided on its surface or inside, for example, made of plastic, an LED element 201 as a light source, a reflective sheet 205, a phase difference plate 206, a lenticular lens, and the like. A liquid crystal display panel 11, equipped with polarizing plates on the light source light incident surface and the image light output surface, is mounted on the upper surface of the light source device 13.

[0158] Furthermore, a film or sheet-like reflective polarizer 49 is provided on the light source light incident surface (lower surface in the figure) of the liquid crystal display panel 11 corresponding to the light source device 13, selectively reflecting one side of the polarization (e.g., S-wave) 211 of the natural light beam 210 emitted from the LED element 201. That is, in the example of Figure 7, the selective reflection characteristics of the reflective polarizer 49 are different from those in Figure 7. The reflected light is reflected by a reflective sheet 205 provided on one side (lower surface in the figure) of the light guide 203 and returns to the liquid crystal display panel 11. A phase difference 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 polarizer 49. The reflected light (reflected light beam) is reflected by the reflective sheet 205 and passes through the phase difference plate (λ / 4 plate) a total of two times, converting it from S-polarized to P-polarized. This improves the efficiency of utilizing the light source as image light. The image light beam, whose light intensity is modulated by the video signal on the liquid crystal display panel 11, is emitted as shown by arrow 214 in Figure 7 and incident on the retroreflector 2. After reflection by the retroreflector 2, a real image, a floating image in space, can be obtained.

[0159] In the light source device 13 shown in Figures 6 and 7, in addition to the action of the polarizer provided on the light incident surface of the corresponding liquid crystal display panel 11, a reflective polarizer reflects one side of the polarization component. Therefore, the theoretically obtainable contrast ratio is the product of the reciprocal of the cross transmittance of the reflective polarizer and the reciprocal of the cross transmittance obtained by the two polarizers attached to the liquid crystal display panel 11. This results in high contrast performance. In actual experiments, it was confirmed that the contrast performance of the displayed image improved by more than 10 times. As a result, high-quality images comparable to those of self-emissive organic EL displays were obtained.

[0160] <Example of display device 2> Figure 8 shows another example of the specific configuration of the display device 1. The light source device 13 of this display device 1 is constructed by housing LEDs, collimators, composite diffusion blocks, light guides, etc., in a case made of, for example, plastic, and a liquid crystal display panel 11 is mounted on the top surface of the light source device 13. In addition, an LED substrate 202 on which semiconductor light sources, namely LED elements 201 and the control circuit for the LED elements 201 are mounted is attached to one side of the case of the light source device 13, and a heat sink 103, which is a component for cooling the heat generated by the LED elements 201 and the control circuit, is attached to the outer surface of the LED substrate 202.

[0161] Furthermore, the liquid crystal display panel frame attached to the top surface of the case of the light source device 13 is configured with a liquid crystal display panel 11 attached to the frame, and an FPC 403 electrically connected to the liquid crystal display panel 11. In other words, the liquid crystal display panel 11, which is the image display element 11, generates a display image by modulating the intensity of transmitted light based on control signals from a control circuit (not shown) that constitutes the electronic device, together with the LED element 201, which is the solid light source.

[0162] <Example of a display device 3> Next, using Figure 9, another example of the specific configuration of the display device 1 (Example 3 of the display device) will be explained. In this display device 1, the light source device converts the divergent luminous flux of light (a mixture of P-polarized and S-polarized light) from the LED 201 into a nearly parallel luminous flux by a collimator (LED collimator) 18, and reflects it toward the liquid crystal display panel 11 by the reflective surface of the reflective light guide 304. The reflected light is incident on a reflective polarizer 49 placed 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, other polarizations other than the specific polarization (e.g., S-polarized light) are reflected by the reflective polarizer 49 and return to the reflective light guide 304.

[0163] The reflective polarizer 49 is installed at an angle to the liquid crystal display panel 11 so as not to be perpendicular to the principal ray of light from the reflective surface of the reflective light guide 304. The principal ray of light reflected by the reflective polarizer 49 is incident on the transmissive surface of the reflective light guide 304. The light incident on the transmissive surface of the reflective light guide 304 passes through the back of the reflective light guide 304, passes through the λ / 4 plate 270 which is a phase difference 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 transmissive surface of the reflective light guide 304. The light that has passed through the transmissive surface of the reflective light guide 304 is incident on the reflective polarizer 49 again.

[0164] At this time, the light that again enters the reflective polarizer 49 has passed through the λ / 4 plate 270 twice, so its polarization has been converted to a polarization that can be transmitted through the reflective polarizer 49 (for example, P-polarization). Therefore, the light whose polarization has been converted passes through the reflective polarizer 49 and enters the liquid crystal display panel 11. Regarding the polarization design related to polarization conversion, it is also acceptable to configure the polarization in reverse from the above explanation (reversing S-polarization and P-polarization).

[0165] As a result, the light from LED201 is aligned to a specific polarization (e.g., P-polarization), incident on the liquid crystal display panel 11, and is luminance-modulated in accordance with the video signal to display an image on the panel surface. Similar to the example described above, there are multiple LED201 that constitute the light source, and these are mounted at predetermined positions for each corresponding collimator 18 of the multiple collimators 18. However, in Figure 9, only one LED201 and one collimator 18 are shown because it is a vertical cross-section.

[0166] Each collimator 18 is formed from a translucent resin such as acrylic or glass. The collimator 18 may have a cone-shaped outer surface obtained by rotating a parabolic cross-section. The collimator 18 may also have a recess with a convex portion (i.e., a convex lens surface) in the center of the top portion (the side facing the LED substrate 202). Furthermore, the central part of the planar portion of the collimator 18 (the side opposite to the top portion) has a convex lens surface that protrudes outward (or a concave lens surface that is recessed inward). The parabolic surface forming the cone-shaped outer surface of the collimator 18 is set within an angle range that allows for total internal reflection of light emitted from the LED 201 in the peripheral direction, or a reflective surface is formed thereon.

[0167] The LEDs 201 are each positioned at predetermined locations on the surface of the LED board 202, which is the circuit board for the LEDs. The LED board 202 is fixed to the collimator 18 such that the LEDs 201 on its surface are each positioned at the center of the apex of the cone-shaped convex form (or in the recess if there is a recess at the apex).

[0168] With this configuration, the collimator 18 focuses the light emitted from the LED 201, particularly the light emitted from its central portion, into parallel light due to the convex lens surface that forms the outer shape of the collimator 18. Similarly, the light emitted from other parts toward the periphery is reflected by the parabolic surface that forms the conical outer surface of the collimator 18, and is also focused into parallel light. In other words, a collimator 18 with a convex lens in its center and a parabolic surface around its periphery makes it possible to extract almost all of the light generated by the LED 201 as parallel light, thereby improving the utilization efficiency of the generated light.

[0169] Furthermore, the light converted to nearly parallel light by the collimator 18 shown in Figure 9 is reflected by the reflective light guide 304. Of this light, light of a specific polarization is transmitted through the reflective polarizer 49 due to the action of the reflective polarizer 49, and the light of the other polarization reflected by the reflective polarizer 49 is transmitted again through the light guide 304. This light is reflected by the reflector 271 located opposite the liquid crystal display panel 11 to the reflective light guide 304. At this time, the light undergoes polarization conversion by passing through the λ / 4 plate 270, which is a phase difference plate, twice. The light reflected by the reflector 271 is transmitted again through the light guide 304 and incident on the reflective polarizer 49 located on the opposite side. Since the polarization conversion has been performed on this incident light, it is transmitted through the reflective polarizer 49, and the polarization direction is aligned before it is incident on the liquid crystal display panel 11. As a result, all of the light from the light source can be utilized, so the geometrical optical utilization efficiency of the light is doubled. Furthermore, since the polarization degree (extinction ratio) of the reflective polarizer 49 is also included in the extinction ratio of the entire system, the contrast ratio of the entire display device is significantly improved by using the light source device of this embodiment. The reflection and diffusion angles of light at each reflective surface can be adjusted by adjusting the surface roughness of the reflective surface of the reflective light guide 304 and the surface roughness of the reflector 271. The surface roughness of the reflective surface of the reflective light guide 304 and the surface roughness of the reflector 271 should be adjusted for each design to further optimize the uniformity of the light incident on the liquid crystal display panel 11.

[0170] Note that the λ / 4 plate 270, which is the phase difference plate in Figure 9, does not necessarily need to have a phase difference of λ / 4 with respect to polarization incident perpendicularly to the λ / 4 plate 270. In the configuration of Figure 9, any phase difference plate that changes its phase by 90° (λ / 2) after the polarization passes through it twice is sufficient. The thickness of the phase difference plate should be adjusted according to the incident angle distribution of the polarization.

[0171] <Example of a display device 4> Furthermore, another example of the optical system configuration of the light source device of the display device 1 (Example 4 of the display device) will be explained using Figure 10. Example 4 of the display device is a configuration example in which a diffusion sheet is used instead of the reflective light guide 304 in the light source device of Example 3 of the display device. Specifically, two optical sheets (in other words, diffusion sheets) that convert the diffusion characteristics in the vertical and horizontal directions (front and back directions not shown in the figure) are used on the light output side of the collimator 18. The two optical sheets are shown as optical sheet 207A and optical sheet 207B. Light from the collimator 18 is incident between the two optical sheets.

[0172] Note that the optical sheet described above may be a single sheet instead of two. If a single sheet is used, the vertical and horizontal diffusion characteristics are adjusted by the fine shape of the front and back surfaces of the single optical sheet. Alternatively, multiple diffusion sheets may be used to share the function. In the example shown in Figure 10, the reflection and diffusion characteristics due to the surface and back surface shapes of optical sheets 207A and 207B should be optimally designed using the number of LEDs 201, the divergence angle from the LED substrate 202, and the optical specifications of the collimator 18 as design parameters so that the surface density of the light beam emitted from the liquid crystal display panel 11 is uniform. In other words, in the example shown in Figure 10, the diffusion characteristics are adjusted by the surface shapes of multiple diffusion sheets instead of a light guide.

[0173] In the example shown in Figure 10, polarization conversion is performed in the same manner as in Example 3 of the display device described above. That is, in the example shown in Figure 10, the reflective polarizer 49 should be configured to have the characteristic of reflecting S-polarized light (and transmitting P-polarized light). In that case, the P-polarized light emitted from the light source LED 201 is transmitted, and the transmitted light is incident on the liquid crystal display panel 11. The S-polarized light emitted from the light source LED 201 is reflected, and the reflected light passes through the phase difference plate 270 shown in Figure 10. The light that has passed through the phase difference plate 270 is reflected by the reflector 271. The light reflected by the reflector 271 is converted to P-polarized light by passing through the phase difference plate 270 again. The polarized light passes through the reflective polarizer 49 and is incident on the liquid crystal display panel 11.

[0174] Note that the λ / 4 plate 270, which is the phase difference plate in Figure 10, does not necessarily need to have a phase difference of λ / 4 with respect to polarization incident perpendicularly to the λ / 4 plate 270. In the configuration of Figure 10, any phase difference plate that changes its phase by 90° (λ / 2) after the polarization passes through it twice is sufficient. The thickness of the phase difference plate should be adjusted according to the incident angle distribution of the polarization. Also, in Figure 10, regarding the polarization design related to polarization conversion, the polarization can be reversed from the explanation above (S-polarization and P-polarization are reversed).

[0175] In typical TV applications, the light emitted from the liquid crystal display panel 11 has similar diffusion characteristics in both the horizontal direction (shown on the X-axis in Figure 12(a)) and the vertical direction (shown on the Y-axis in Figure 12(b)). In contrast, the diffusion characteristics of the light beam emitted from the liquid crystal display panel 11 in this embodiment are such that, for example, as shown in Example 1 in Figure 12, the viewing angle at which the brightness is 50% of that of a front view (0-degree angle) is 13 degrees, which is 1 / 5 of the 62 degrees of a typical TV application. Similarly, the vertical viewing angle is made uneven, with the upper viewing angle being reduced to about 1 / 3 of the lower viewing angle by optimizing the reflection angle of the reflective light guide and the area of ​​the reflective surface. As a result, the amount of image light directed towards the monitoring direction is significantly improved compared to conventional LCD TVs, and the brightness is more than 50 times higher.

[0176] Furthermore, with the viewing angle characteristics shown in Example 2 of Figure 12, the viewing angle at which the brightness is 50% of that of a front view (0-degree angle) is set to 5 degrees, which is 1 / 12 of the 62 degrees of a typical TV device. Similarly, the vertical viewing angle is made uniform both vertically and horizontally, and the reflection angle of the reflective light guide and the area of ​​the reflective surface are optimized to reduce the viewing angle to about 1 / 12 of that of a typical TV device. As a result, the amount of image light directed towards the monitoring direction is significantly improved compared to conventional LCD TVs, and the brightness becomes more than 100 times higher.

[0177] As described above, by narrowing the viewing angle, the amount of light flux directed towards 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, a significant increase in brightness can be achieved with similar power consumption, making it possible to create a video display device that is suitable for information display systems for bright outdoor environments.

[0178] When using a large LCD display panel, the overall brightness of the screen can be improved by directing the light from the edges of the screen inward so that it is directed towards the monitor when the monitor is facing the center of the screen. Figure 11 shows the convergence angles of the long and short sides of the panel, with the monitor's distance L from the panel and the panel size (screen aspect ratio 16:10) as parameters. When monitoring with the screen in portrait orientation, the convergence angle should be set to match the short side. For example, with a 22-inch panel used vertically and a monitoring distance of 0.8m, setting the convergence angle to 10 degrees will effectively direct the image light from the four corners of the screen towards the monitor.

[0179] Similarly, when monitoring with a 15-inch panel in portrait orientation, if the monitoring distance is 0.8m, a convergence angle of 7 degrees will effectively direct the image light from the four corners of the screen towards the monitor. As described above, depending on the size of the LCD display panel and whether it is used vertically or horizontally, 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 optimal position to monitor the center of the screen.

[0180] In its basic configuration, as shown in Figure 9, a light source device emits a light beam with narrow-angle directional characteristics onto the liquid crystal display panel 11. By modulating the brightness in accordance with the video signal, the video information displayed on the screen of the liquid crystal display panel 11 is reflected by a retroreflector, and the resulting floating image is displayed outdoors or indoors via a transparent member 100.

[0181] By using the display device and light source device according to one embodiment of the present invention described above, it becomes possible to realize a spatial floating image display device with higher light utilization efficiency.

[0182] <Example of video display processing in a spatially floating video display device> Next, an example of a problem that the image processing of this embodiment solves will be explained using Figure 13A. In the floating spatial image display device 1000 (Figures 3, 4A to 4P), when viewed from the user, the area behind the floating spatial image 3 is inside the housing of the floating spatial image display device 1000, and if it is sufficiently dark, the user will perceive the background of the floating spatial image 3 as black.

[0183] Here, using Figure 13A, we will explain an example of displaying the character "Panda" 1525 in the floating spatial image 3. First, the image control unit 1160 in Figure 3 distinguishes and recognizes the pixel area for drawing the image of the character "Panda" 1525 and the transparent information area 1520, which is the background image, in an image that includes both the pixel area for drawing the image of the character "Panda" 1525 and the transparent information area 1520, which is the background image, as shown in Figure 13A(1).

[0184] One method for distinguishing and recognizing character images and background images is 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 images and background images can be distinguished and recognized based on the superposition relationship when these layers are combined.

[0185] Here, the video control unit 1160 recognizes the black pixels that render objects such as character images and the transparent information pixels as different information. However, it is assumed that both the black pixels that render objects and the transparent information pixels have a brightness of 0. In this case, when displaying the floating spatial image 3, there is no difference in brightness between the pixels that render black in the image of the character "panda" 1525 and the pixels of the transparent information area 1520, which is the background image. Therefore, in the floating spatial image 3, as shown in Figure 13A(2), neither the pixels that render black in the image of the character "panda" 1525 nor the pixels of the transparent information area 1520 have brightness, and are optically perceived by the user as the same black space. In other words, the parts of the image of the character "panda" 1525 that are rendered in black blend into the background, and only the non-black parts of the character "panda" 1525 are perceived as floating images in the display area of ​​the floating spatial image 3.

[0186] An example of image processing in this embodiment will be explained using Figure 13B. Figure 13B illustrates an example of image processing that more effectively resolves the problem described in Figure 13A, where the black image area of ​​an object blends into the background. In Figures 13B(1) and (2), the display state of the floating spatial image 3 is shown on the upper side, and the input / output characteristics of the image processing of the object's image are shown on the lower side. The image of the object (character "Panda" 1525) and its corresponding data may be read from the storage unit 1170 or memory 1109 in Figure 3. Alternatively, it may be input from the video signal input unit 1131. Alternatively, it may be acquired via the communication unit 1132.

[0187] In the state shown in Figure 13B(1), the input / output characteristics of the image processing of the object's image are in a linear state with no special adjustments. In this case, the display state is the same as 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 object (character "Panda" 1525) to the input / output characteristics shown in the lower section.

[0188] In other words, the video control unit 1160 performs input-output characteristic image processing on the image of the object (character "Panda" 1525), which has the characteristic of converting the pixels of the input image into output pixels with increased brightness values ​​for pixels in the low-brightness region. After the image of the object (character "Panda" 1525) is subjected to this input-output characteristic image processing, the video including the image of the object (character "Panda" 1525) is input to the display device 1 and displayed. As a result, the display state of the floating video 3 is as shown in the upper part of Figure 13B(2), where the brightness of the pixel regions that draw black in the image of the character "Panda" 1525 increases. This makes it possible to distinguish the regions that draw black within the area where the image of the character "Panda" 1525 is drawn from the black background and allow the user to recognize it, making it possible to display the object more favorably.

[0189] In other words, by using the image processing shown in Figure 13B(2), the area displaying the image of the object character "Panda" 1525 can be distinguished from the black background inside the housing of the floating image display device 1000 via the window, thereby improving the visibility of the object. Therefore, for example, even if an object contains pixels with a brightness value of 0 before the image processing (i.e., when the image of the object and its corresponding data are read from the storage unit 1170 or memory 1109 in Figure 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 acquired via the communication unit 1132, etc.), the image processing of the input / output characteristics by the video control unit 1160 converts it into an object with increased brightness values ​​in the low-brightness region, which is then displayed on the display device 1 and converted into a floating image 3 by the optical system of the floating image display device 1000.

[0190] In other words, the pixels constituting the object after image processing of the input / output characteristics are converted to a state in which pixels with a brightness value of 0 are not included, and then displayed on the display device 1, and converted into a floating image 3 by the optical system of the floating image display device 1000.

[0191] Furthermore, in the image processing shown in Figure 13B(2), one method for applying the input / output characteristics image processing shown in Figure 13B(2) only to the area of ​​the object (character "Panda" 1525) image is 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 input / output characteristics image processing shown in Figure 13B(2) is applied to the character image layer, while the background image layer is not subjected to the same image processing.

[0192] Subsequently, when these layers are combined, as shown in Figure 13B(2), only the character image will be subjected to image processing that enhances the low-luminance areas of the input image. Alternatively, the character image layer and the background image layer may be combined first, and then the image processing with the input / output characteristics shown in Figure 13B(2) may be applied only to the character image area.

[0193] Furthermore, the input / output video characteristics used in video processing to enhance the low-luminance region of the input / output characteristics for the input video are not limited to the example shown in Figure 13B(2). Any video processing that enhances low luminance is acceptable, including so-called bright adjustment. Alternatively, video processing that improves visibility may be performed by controlling the gain that changes the weighting of the retinex processing, as disclosed in International Publication No. 2014 / 162533.

[0194] As explained above, the image processing shown in Figure 13B(2) allows for the rendering of black areas within the image rendering area, such as characters and objects, to be recognized by the user without blending into the black background, thereby achieving a more suitable display.

[0195] In the examples shown in Figures 13A and 13B, the challenges and more suitable image processing methods were explained using spatial levitation image display devices where the background appears black (for example, the spatial levitation image display device 1000 in Figures 4A to 4G, or the spatial levitation image display device 1000 in Figures 4I and 4J with the rear window shading). However, this image processing method is also effective for devices other than these spatial levitation image display devices.

[0196] Specifically, in the floating image display device 1000 shown in Figure 4H, and in the floating image display device 1000 shown in Figures 4I and 4J with the rear window not shading, the background of the floating image 3 is not black, but rather the scenery behind the floating image display device 1000 through the window. In this case as well, the problems described in Figures 13A and 13B still exist.

[0197] In other words, the parts of the image of the character "Panda" 1525 that are rendered in black blend into the scenery behind the floating video display device 1000 through the window. In this case as well, by using the image processing shown in Figure 13B(2), the parts of the image of the character "Panda" 1525 that are rendered in black can be distinguished and recognized from the scenery behind the floating video display device 1000 through the window, thereby improving the visibility of the object.

[0198] In other words, by using the image processing shown in Figure 13B(2), the area displaying the image of the object character "Panda" 1525 can be distinguished from the scenery behind the spatially floating image display device 1000 through the window, making it more favorable to recognize that the object character "Panda" 1525 is in front of the scenery, thereby improving the visibility of the object.

[0199] Furthermore, in the floating image display device 1000 shown in Figures 4K, 4L, and 4M, as described above, if another image (such as the image from the transmissive self-emissive image display device 1650 or the image from the second display device 1680) is displayed at a different depth from the floating image 3, the background of the floating image 3 will not be black, but will be that other image. In this case as well, the problems described in Figures 13A and 13B still exist.

[0200] In other words, the parts of the image of the object character "Panda" 1525 that are rendered in black blend into the other image which is displayed at a different depth from the floating spatial image 3. In this case as well, by using the image processing shown in Figure 13B(2), the parts of the image of the object character "Panda" 1525 that are rendered in black can be distinguished and recognized from the other image, thereby improving the visibility of the object.

[0201] In other words, by using the image processing shown in Figure 13B(2), the area displaying the image of the object character "Panda" 1525 can be recognized separately from the other video, making it more favorable to recognize that the object character "Panda" 1525 is in front of the other video, thereby improving the visibility of the object.

[0202] An example of the video display processing in this embodiment will be explained using Figure 13C. Figure 13C is an example of video display in this embodiment in which the floating video 3 and a second image 2050, which is another video, are displayed simultaneously. The second image 2050 may correspond to the display video of the transmissive self-emissive video display device 1650 in Figure 4K or Figure 4L. Alternatively, the second image 2050 may correspond to the display video of the second display device 1680 in Figure 4M.

[0203] In other words, the example of video display in Figure 13C is a concrete example of the video display example of the spatial floating video display device 1000 shown in Figures 4K, 4L, and 4M. In this example, a bear character is displayed in spatial floating video 3. Areas other than the bear character in spatial floating video 3 are displayed in black and are transparent as spatial floating video. The second image 2050 is a background image depicting a plain, mountains, and the sun.

[0204] In Figure 13C, the floating image 3 and the second image 2050 are displayed at different depths. By viewing the two images, floating image 3 and the second image 2050, in the line of sight indicated by arrow 2040, user 230 can see the two images superimposed. Specifically, the bear character from floating image 3 appears superimposed in front of the background of plains, mountains, and the sun depicted in the second image 2050.

[0205] Here, since the floating image 3 is projected as a real image in the air, when user 230 slightly moves their viewpoint, they can perceive the depth of the floating image 3 and the second image 2050 due to parallax. Therefore, user 230 can view the two images superimposed and obtain a stronger sense of floating in the floating image 3.

[0206] An example of the video display processing in this embodiment will be explained using Figure 13D. Figure 13D(1) is a view of the floating-in-space video 3 from the user 230's line of sight, as seen in the example of video display in this embodiment shown in Figure 13C. Here, a bear character is displayed in the floating-in-space video 3. Areas other than the bear character in the floating-in-space video 3 are displayed in black and are transparent as a floating-in-space video.

[0207] Figure 13D(2) is a view of the second image 2050 from the user 230's line of sight, as seen in the example of video display of this embodiment in Figure 13C. In this example, the second image 2050 is a background image depicting a plain, mountains, and the sun.

[0208] Figure 13D(3) shows an example of the video display in this embodiment of Figure 13C, where the second image 2050 and the floating spatial image 3 appear superimposed in the user 230's line of sight. Specifically, the bear character from the floating spatial image 3 appears superimposed in front of the background of plains, mountains, and the sun depicted in the second image 2050.

[0209] Here, when displaying the floating image 3 and the second image 2050 simultaneously, it is desirable to pay attention to the balance of brightness between the two images in order to better ensure the visibility of the floating image 3. If the second image 2050 is too bright compared to the brightness of the floating image 3, the displayed image of the floating image 3 will become transparent, and the background, the second image 2050, will become transparent and strongly visible.

[0210] Therefore, the output of the light source for the floating image 3 and the display image brightness of the display device 1, as well as the output of the light source of the display device that displays the second image 2050 and the display image brightness of the display device, should be set such that the brightness per unit area of ​​the floating image 3 at the display position of the floating image 3 is greater than the brightness per unit area of ​​the image light reaching the display position of the floating image 3 from the second image 2050.

[0211] Furthermore, since this condition only needs to be met when the floating image 3 and the second image 2050 are displayed simultaneously, when switching from the first display mode, which displays only the second image 2050 without displaying the floating image 3, to the second display mode, which displays the floating image 3 and the second image 2050 simultaneously, 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 can be achieved by the control unit 1110 in Figure 3 controlling the display device 1 and the display device that displays the second image 2050 (the transmissive self-emissive image display device 1650 in Figure 4K or Figure 4L, or the second display device 1680 in Figure 4M).

[0212] Furthermore, when switching from the first display mode to the second display mode described above, 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 uniformly reducing the brightness across the entire screen of the second image 2050, the area where an object is displayed in the floating spatial image 3 may be set to the state with the highest brightness reduction effect, and the brightness reduction effect may be gradually reduced in the surrounding areas. In other words, if the brightness reduction of the second image 2050 is achieved only in the area where the floating spatial image 3 is superimposed on the second image 2050 and visible, the visibility of the floating spatial image 3 can be sufficiently ensured.

[0213] Here, since the floating image 3 and the second image 2050 are displayed at different depths, if the user 230 slightly changes their viewpoint, the superimposed position of the floating image 3 on the second image 2050 changes due to parallax. Therefore, when switching from the first display mode to the second display mode described above, if the brightness is to be reduced unevenly across the entire screen of the second image 2050, it is not desirable to sharply reduce the brightness based on the outlines of the objects displayed in the floating image 3. Rather, it is desirable to perform a gradient processing of the brightness reduction effect, which changes the brightness reduction effect stepwise depending on the position, as described above.

[0214] In the case of the floating image display device 1000, where the position of the object displayed in the floating image 3 is approximately in the center of the floating image 3, the position where the brightness reduction effect of the gradient processing is highest should be the center of the floating image 3.

[0215] According to the video display processing of this embodiment described above, the user 230 can more favorably view the floating video 3 and the second image 2050.

[0216] Furthermore, when displaying the floating image 3, the display of the second image 2050 may be controlled to be disabled. Disabling the display of the second image 2050 improves the visibility of the floating image 3, so this control is suitable for floating image display devices 1000 and the like in applications where the user must be able to clearly see the floating image 3 when it is displayed.

[0217] <Example 2> As Embodiment 2 of the present invention, an example of another configuration of the floating image display device will be described. In this embodiment, the floating image display device is modified from the one described in Embodiment 1 by changing the optical system stored in the floating image display device to the optical system shown in Figure 14(1) or Figure 14(2). In this embodiment, the differences from Embodiment 1 will be explained, and the same configuration as in Embodiment 1 will not be repeated. In the following description of this embodiment, the predetermined polarization and the other polarization are polarizations with a phase difference of 90° from each other.

[0218] Figure 14(1) shows an example of the optical system and optical path according to this embodiment. The optical system shown in Figure 14(1) is a more compact configuration of the optical system in Figure 2C, with the display device 1 closer to the polarization separation member 101B. Detailed explanations of components in Figure 14(1) that have the same reference numerals as in Figure 2C will be omitted.

[0219] In Figure 14(1), similar to Figure 2C, image light of a predetermined polarization (P-polarization in the figure) emitted from the display device 1 propagates perpendicularly from the image display surface of the display device 1. Here, the polarization separation member 101B, similar to Figure 2C, selectively transmits the predetermined polarization (P-polarization in the figure) emitted from the display device 1 and reflects the other polarization (S-polarization in the figure).

[0220] Therefore, the image light with a predetermined polarization (P polarization in the figure) that travels perpendicularly from the image display surface of the display device 1 passes through the polarization separation member 101B and reaches the retroreflector 2 to which the λ / 4 plate 21 is attached. The image light that is retroreflected by the retroreflector 2 and travels again toward the polarization separation member 101B has been converted from the predetermined polarization (P polarization in the figure) when emitted from the display device 1 to the other polarization (S polarization in the figure) by passing through the λ / 4 plate 21 twice. The image light that travels again toward the polarization separation member 101B is the other polarization (S polarization in the figure), and is therefore reflected by the polarization separation member 101B toward the position where the user should be. The direction of propagation of the image reflected by the polarization separation member 101B is determined based on the angle at which the polarization separation member 101B is positioned.

[0221] In the example shown in Figure 14(1), the image light traveling toward the polarization separation member 101B is reflected at a right angle by the polarization separation member 101B and travels as shown in the figure. The image light reflected by the polarization separation member 101B forms a floating image 3A. The floating image 3A can be preferably viewed by the user from the direction of arrow A.

[0222] Here, due to the retroreflective properties of the retroreflector 2, the optical path length from the image light emitted from the display device 1 to the retroreflector 2 is equal to the optical path length from the image light emitted from the retroreflector 2 to the position where the floating image 3A is formed. This relationship determines the position where the floating image 3A is formed in the direction of propagation of the image light reflected by the polarization separation member 101B.

[0223] In the example in Figure 14(1), the display device 1, the polarization separation member 101B, and the retroreflector 2 are arranged closer together than in the example in Figure 2C. This makes the entire optical system more compact. However, the amount of floating image 3A that flies out from the optical system in Figure 14(1) is not very large. For example, as one indicator of the amount of floating image 3A that flies out from the optical system, the distance (L1 in the example in Figure 14(1)) from the position where the light rays from the center of the image light are reflected by the polarization separation member 101B to the position where the image light forms the floating image 3A is shown in the figure.

[0224] Furthermore, regarding the polarization design in the optical system shown in Figure 14(1), the characteristics of P-polarization and S-polarization may be swapped. Specifically, a predetermined polarization of the image light emitted from the display device 1 may be defined as S-polarization, and the reflection characteristics of the polarization separation member 101B may be swapped between P-polarization and S-polarization. In this case, although the P-polarization and S-polarization shown will be reversed, the optical design, such as the optical path, can be realized in exactly the same way.

[0225] Next, Figure 14(2) shows another example of the optical system and optical path according to this embodiment. The optical system in Figure 14(2) is a modified version of the optical system in Figure 14(1) that achieves the same compactness as the optical system in Figure 14(1) while increasing the amount of spatially floating image projected from the optical system. Detailed explanations of components in Figure 14(2) that are given the same reference numerals as in Figure 14(1) will be omitted.

[0226] In Figure 14(2), similar to Figure 14(1), image light with a predetermined polarization (P-polarization in the figure) emitted from the display device 1 travels perpendicularly from the image display surface of the display device 1. Here, the polarization characteristics of the polarization separation member 101B are arranged 90 degrees differently from those in Figure 14(1). The image light with the predetermined polarization (P-polarization in the figure) traveling perpendicularly from the image display surface of the display device 1 passes through the polarization separation member 101B.

[0227] Here, unlike in Figure 14(1), the image light, after passing through the polarization separation member 101B, is positioned not on the retroreflector 2 to which the λ / 4 plate 21 is attached, but on the specular reflector 4 to which the λ / 4 plate 21B is attached. Here, the reflection at the specular reflector 4 is specular reflection (also called specular reflection), and not retroreflection.

[0228] Therefore, the video light transmitted through the polarization separation member 101B is specularly reflected by the specular reflection plate 4 to which the λ / 4 plate 21B is attached. The video light that is specularly reflected by the specular reflection plate 4 and travels again toward the polarization separation member 101B is converted from a predetermined polarization (P polarization in the figure) at the time of emission from the display device 1 to the other polarization (S polarization in the figure) by passing through the λ / 4 plate 21 twice. Since the video light that travels again toward the polarization separation member 101B is the other polarization (S polarization in the figure), it is reflected by the polarization separation member 101B.

[0229] Here, since the orientation of the polarization separation member 101B in Fig. 14(2) is different from that in Fig. 14(1), the video light reflected by the polarization separation member 101B travels in the opposite direction to the position where the user should be. A retroreflective plate 2 to which the λ / 4 plate 21C is attached is arranged at the destination where the video light reflected by the polarization separation member 101B travels. The video light is retroreflectively reflected by the retroreflective plate 2. The video light that is retroreflectively reflected by the retroreflective plate 2 and travels again toward the polarization separation member 101B is converted from the other polarization (S polarization in the figure) to the predetermined polarization (P polarization in the figure) again by passing through the λ / 4 plate 21C twice.

[0230] Since the video light that travels again toward the polarization separation member 101B is the predetermined polarization (P polarization in the figure), it passes through the polarization separation member 101B and travels directly toward the position where the user should be. The video light passing through the polarization separation member 101B forms a spatial floating image 3B. The spatial floating image 3B can be preferably visually recognized by the user from the direction of arrow A.

[0231] Here, also in Fig. 14(2), similar to Fig. 14(1), due to the characteristics of the retroreflective reflection by the retroreflective plate 2, the optical path length from the display device 1 to the point where the video light reaches the retroreflective plate 2 is equal to the optical path length from the retroreflective plate 2 to the point where the video light reaches the formation position of the spatial floating image 3B. Based on this relationship, the formation position of the spatial floating image 3B in the traveling direction of the video light passing through the polarization separation member 101B is determined.

[0232] In FIG. 14(2), the optical path length from the display device 1 to the retroreflector 2 where the video light emitted from the display device 1 reaches is longer than the optical path length from the display device 1 to the retroreflector 2 in FIG. 14(1). In the optical system of FIG. 14(2), an optical path that reciprocates between the polarization separation member 101B and the specular reflector 4, which does not exist in the optical system of FIG. 14(1), is added to the optical path length until the video light emitted from the display device 1 reaches the retroreflector 2.

[0233] As a result, in the optical system of FIG. 14(2), the distance (L2 in the example of FIG. 14(2)) from the position where the light rays of the central part of the video light pass through the polarization separation member 101B to the position where the video light forms the spatial floating image 3B is significantly longer than the distance (L1 in the example of FIG. 14(1)) from the position where the light rays of the central part of the video light are reflected by the polarization separation member 101B to the position where the video light forms the spatial floating image 3A in the optical system of FIG. 14(1).

[0234] Regarding the polarization design in the optical system of FIG. 14(2), the characteristics of P-polarized light and S-polarized light may be interchanged. Specifically, a predetermined polarization of the video light emitted from the display device 1 may be set as S-polarized light, and the reflection characteristics of the polarization separation member 101B may have the characteristics of P-polarized light and S-polarized light interchanged. In this case, although both the illustrated P-polarized light and S-polarized light are reversed, the optical design such as the optical path can be realized in exactly the same way.

[0235] According to the optical systems of FIGS. 14(1) and 14(2) in the second embodiment of the present invention described above, a more compact optical system can be realized. In particular, according to the optical system of FIG. 14(2), it is possible to make the amount by which the spatial floating image jumps out from the optical system larger while having a more compact optical system.

[0236] Furthermore, when incorporating the optical system shown in Figure 14(1) or Figure 14(2) into a floating image display device, this can be achieved by replacing the optical system in the floating image display device described in Example 1 with the optical system shown in Figure 14(1) or Figure 14(2). Specifically, the optical system in Figure 14(1) may be replaced with the optical system of the floating image display device shown in Figures 4E, 4F, 4G, 4H, 4I, 4J, 4K, 4L, or 4M. In this case, the optical system becomes more compact, making it possible to further reduce the size of the housing of the floating image display device shown in each figure.

[0237] Furthermore, the optical system in Figure 14(2) may be replaced with the optical system of the levitating image display device in Figures 4E, 4F, 4G, 4K, or 4L. In this case, it becomes possible to increase the amount of levitating image projected from the optical system. Also, since the optical system becomes more compact, it becomes possible to make the housing of the levitating image display device in each figure smaller.

[0238] <Example 3> As Embodiment 3 of the present invention, an example configuration of a floating image display device will be described. The floating image display device according to this embodiment can be configured in the same way as the configurations shown in the figures described in Embodiments 1 and 2. In this embodiment, the differences from Embodiments 1 and 2 will be mainly described, and the same configurations as in Embodiments 1 and 2 will not be repeated.

[0239] [Comparative Example 1] Figure 15 shows an example configuration of the optical system and other components of a comparative example to Example 3. This example configuration is based on the optical system configuration of Figure 2D described above. Here, the two orthogonal directions constituting the horizontal plane are defined as the X and Y directions, and the vertical direction is defined as the Z direction. This comparative example has an optical plate 150 and a display device 1. The display device 1 is, in other words, an image display unit and a display unit. The display device 1 has a light source device 13 that generates light and a liquid crystal display panel 11 which is a display element that displays an image based on that light. The optical plate 150 has a transparent member 100 such as glass and a retroreflective plate (in other words, a retroreflective member) 5 provided on the lower surface of the transparent member 100. The optical plate 150 is arranged on a horizontal plane. The display device 1 is positioned diagonally below the optical plate 150. The display device 1 is arranged so that the image light emitting surface (in other words, the display surface) of the liquid crystal display panel 11 is tilted diagonally. The principal ray 9020A of the video light a1 emitted from the video light output surface of the display device 1 is shown with a solid arrow, and the upper and lower ends of the video light beam are shown with dashed lines.

[0240] The principal ray 9020A, which represents the luminous flux of the image light a1 emitted from the image light emission surface of the display device 1, travels toward point P on the retroreflector 5 and is incident on the retroreflector 5 at a predetermined incident angle α. In this comparative example, the incident angle α is 65 degrees. Here, the incident angle α is the angle with respect to the normal direction of the plane of the retroreflector 5. The angle of incidence of the principal ray 9020A with respect to the plane of the retroreflector 5 is αA = 90 degrees - α = 25 degrees.

[0241] In Example 3 and subsequent examples, the angle of incidence and the angle of exit are defined and used as angles with respect to the normal direction of the incident plane, as shown by angle α. Since it depends on the definition, the main point remains the same even if the angle of incidence and the angle of exit are defined as angles with respect to the incident plane.

[0242] The principal ray 9020A, due to the action of the retroreflector 5, passes through the transparent member 100 and propagates in the Z direction while being retroreflected in the X and Y directions. As a result, the reflected ray 9021A, which represents the luminous flux of the retroreflected image light a2, after passing through the transparent member 100, propagates away from the retroreflector 5 in a mirror-symmetric optical path with respect to the principal ray 9020A, relative to the retroreflector 5, and forms a floating image 3 (in other words, a standing image 3A) as a real image at the imaging plane. The emission angle of the reflected ray 9021A is 65 degrees, the same as the incident angle α, and αA = 25 degrees with respect to the plane of the retroreflector 5.

[0243] Based on the method described in Figure 2D, we consider obtaining a spatially floating image 3 (upright image 3A) with a 65-degree inclination relative to, for example, the horizontal plane and the optical plate 150 including the retroreflective plate 5, as shown in Figure 15. Let B = 65 degrees be the inclination angle (in other words, the upright image angle) of the spatially floating image 3 (upright image 3A) with respect to the horizontal plane.

[0244] To achieve this, the display device 1 is tilted downwards from the optical plate 150, which includes the retroreflector 5, at an angle of 65 degrees, the same as the tilt angle B. As a result, the principal ray 9020A, which represents the light beam of the image light a1 emitted perpendicular to the surface at a 90-degree angle from the image light emission surface of the display device 1, has an incidence angle α of 65 degrees on the retroreflector 5. Correspondingly, the emission angle of the retroreflected light becomes 65 degrees. This forms an upright image 3A with a tilt angle B = 65 degrees.

[0245] In this comparative example, θA is defined as the observation angle corresponding to the observation direction AU (in other words, the line of sight direction) when observing the standing image 3A from the user's viewpoint (schematically shown as viewpoint position 232). This observation angle θA is set to a downward angle of 25 degrees, matching the angle αA of the emission of the image light a2. When observing the standing image 3A with an observation angle θA of a downward angle of 25 degrees, suitable visibility corresponding to the luminance peak A1 is possible.

[0246] As mentioned above, in the case of an optical system like the one shown in Figure 2D, the angle of incidence of the light beam emitted from the display device 1 to the retroreflector 5 (in Figure 2D, this is the angle with respect to the plane of the retroreflector 5, but the same can be considered if the angle is with respect to the normal direction of the retroreflector 5) is used to be around 45 degrees. This is because, based on the device characteristics and optical principles of the retroreflector 5, the reflection efficiency of the incident image light at the retroreflector 5 is highest when the angle of incidence is 45 degrees, resulting in the best peak brightness when observing the floating image 3. The peak brightness decreases as the angle of incidence moves away from 45 degrees.

[0247] However, in this comparative example, the incident angle α = 65 degrees and the corresponding angle αA = 25 degrees deviate from 45 degrees, which is the incident angle at which the reflection efficiency of the incident image light is highest. Specifically, there is a deviation of 65 degrees - 45 degrees = 20 degrees. Therefore, the luminance peak A1 of the standing image 3A generated in this comparative example is lower than that of the 45-degree case in Figure 2D.

[0248] Furthermore, in order to display the entire image emitted from the display device 1 on the screen of the floating image 3 at an incident angle α = 65 degrees and a corresponding angle αA = 25 degrees in this comparative example, an optical plate 150 including a retroreflector 5 that is longer than the length of the image light emission surface of the display device 1 is required, as shown in Figure 15. In Figure 15, the length of the optical plate 150 in the depth direction (Y direction) is 1591. As a result, in order to obtain a floating image 3 with a sufficiently large screen, the floating image display device will need to be enlarged. In particular, the length of the optical plate 150 in the depth direction will increase.

[0249] [Comparative Example 2] In contrast, to prevent the spatial levitation image display device from becoming too large, it is necessary to use an optical plate 150 that includes a relatively short retroreflective plate 5, as shown in the comparative example in Figure 16. The comparative example in Figure 16 shows the suppression and limitation of the length of the optical plate 150 in the depth direction (Y direction) and the reduction of the size of the spatial levitation image 3 in the vertical direction on the screen (in other words, the display range), while maintaining the same basic configuration as in Figure 15. In the comparative example in Figure 16, the optical plate 150 is given a length of 1592, as there is a limitation that the length in the depth direction (Y direction) cannot be made too long.

[0250] However, in the comparative example shown in Figure 16, the length 1592 of the optical plate 150 does not partially cover the range of the light beam of the image light from the display surface of the display device 1. Specifically, the light ray 9023A emitted from the lower end (point p1) of the image light emission surface of the display device 1 reaches point 9024A on the horizontal plane corresponding to the optical plate 150 where the retroreflector 5 does not exist, and therefore is not retroreflected, and no floating image corresponding to this light ray 9023A is generated. In this comparative example, the light ray 9024A emitted from approximately the center position (point p3) of the image light emission surface of the display device 1 travels to the edge (point Q) of the retroreflector 5 that is close to point P in the Y direction (depth direction, front-to-back direction). Therefore, the floating image generated by traveling a mirror-symmetric optical path away from the retroreflector 5 from this edge (point Q) becomes the upper end (point q2) of the upright image 3Ab.

[0251] Therefore, as shown in Figure 16, the image below the approximately central position (point p3) of the display device 1 cannot be seen by the user as the floating image 3, and the vertical viewing range becomes narrower. In other words, as shown in Figure 16, when the length of the optical plate 150 is reduced, the screen of the floating image 3 becomes about half the size in the vertical direction of the screen compared to Figure 15. When the standing image 3A is observed from the user's viewpoint position 232 at an observation angle θA, the floating image cannot be seen above point q2.

[0252] Even if one wishes to realize a standing image 3A with a tilt angle of 65 degrees as in the above comparative example, there are limitations to the length of the depth of the optical plate 150 depending on the use and implementation of the spatial floating image display device 1000. When suppressing the length of the optical plate 150 to achieve miniaturization, as in the comparative example of FIG. 16, the size of the screen of the standing image 3A becomes small.

[0253] [Optical System of the Spatial Floating Image Display Device of Example 3] FIG. 17 shows a configuration example of an optical system and the like, which is a main part in the spatial floating image display device 1000 of Example 3. In this Example 3, a spatial floating image 3 as a standing image 3A with high brightness and easy visibility is realized. This standing image 3A is formed as a floating image of a plane standing at an angle closer to vertical than horizontal by being arranged at an inclination of, for example, 65 degrees with respect to the optical plate 150 arranged on the horizontal plane. Corresponding to the tilt angle B = 65 degrees of the standing image 3A, the angle formed by the standing image 3A with respect to the vertical direction is 25 degrees (90 degrees - 65 degrees = 25 degrees).

[0254] The optical system shown in FIG. 17 is configured as an optical system suitable for a viewer, i.e., a user, to observe the standing image 3A, which is the spatial floating image 3, from diagonally above at a relatively high angle, that is, at an observation angle (depression angle) θB in FIG. 17 deeper than the observation angle (depression angle) θA of the comparative example. In the example of FIG. 17, θB = 45 degrees. In other words, in this Example 3, when observing a standing image 3A of 65 degrees at a depression angle of 45 degrees, the optical system and the like are configured so that a suitable spatial floating image 3 having a luminance peak B1 can be visually recognized. Specifically, with respect to the optical plate 150 arranged on the horizontal plane, while the display device 1 and the spatial floating image are arranged in a mirror symmetry at 65 degrees, a prism sheet 300 is provided on the surface of the display device 1 such that the incident angle α and the exit angle α of the image light with respect to the retroreflective plate 5 are 45 degrees.

[0255] As shown in Figure 17, in this embodiment 3, similar to the comparative example in Figure 15, the display device 1, including the liquid crystal display panel 11, is positioned at a 65-degree inclination angle relative to the optical plate 150, which includes the retroreflector 5. Then, the image light from the display surface of the liquid crystal display panel 11, which is the image light emission surface, is incident on the retroreflector 5 at an incident angle α = 45 degrees and a corresponding angle αB = 45 degrees. For this purpose, the refraction effect of the prism sheet 300 provided on the surface of the liquid crystal display panel 11 is used.

[0256] Figure 17 shows a major difference from the comparative example in Figure 15: the prism sheet 300, which achieves a predetermined refraction angle (let's call it C), is positioned close to the image light emission surface of the liquid crystal display panel 11 of the display device 1. The display device 1 equipped with the prism sheet 300 is referred to as display device 1B. The prism sheet 300 is positioned close to the display surface of the liquid crystal display panel 11. For example, the prism sheet 300 may be attached to the display surface of the liquid crystal display panel 11. The image light emitted from the liquid crystal display panel 11 in a direction perpendicular to the display surface is refracted by the prism sheet 300 from the direction of angle βA = 90 degrees in Figure 15 (the direction of the light ray 9020A in Figure 17) to the direction of βB = 70 degrees, which is a desired angle (the image light emission angle corresponding to the desired incident angle). In other words, in this example, the refraction angle C by the prism sheet 300 is 20 degrees. An example of the configuration of the prism sheet 300 will be described later.

[0257] In this embodiment 3, the principal ray 9020B, which represents the luminous flux of the image light b1 emitted perpendicular to the display surface of the liquid crystal display panel 11 of the display device 1, is refracted at C=20 degrees relative to the direction perpendicular to the display surface by the refraction action of the prism sheet 300 as it travels toward the retroreflector 5. As a result, it becomes a ray with an angle βB=70 degrees relative to the display surface and travels toward the retroreflector 5. The dashed ray corresponds to the ray 9020A that is emitted perpendicular to the display surface and travels toward the aforementioned point P when there is no refraction action. As a result, the principal ray 9020B of the image light b1 has an incident angle α of 45 degrees toward the retroreflector 5 (point Pb), and correspondingly the angle αB of the retroreflector 5 with respect to the plane is 45 degrees.

[0258] As mentioned above, for an optical system like the one in Figure 2D, the reflection efficiency of the incident image light at the retroreflector 5 is highest when the incident angle is 45 degrees, and a luminance peak due to retroreflected light is obtained. In this embodiment 3 (Figure 17), since the incident angle α = 45 degrees and the corresponding angle αB = 45 degrees, retroreflected light is emitted at an exit angle α = 45 degrees and the corresponding angle αB = 45 degrees. The luminance peak B1 of the floating image 3A, which is generated by the principal ray 9021B of the retroreflected image light b2, is highest when observed at a downward angle of 45 degrees, where the observation angle θB corresponds to the observation direction BU from the user's viewpoint position 232. Therefore, in this embodiment 3 (Figure 17), the problem of the luminance peak A1 of the 65-degree standing image 3A decreasing, as in the comparative example in Figure 15, is improved, and the user, as the observer, can easily see the 65-degree standing image 3A, and it is particularly suitable for viewing when observed at a downward angle θB = 45 degrees.

[0259] Furthermore, in this embodiment 3 (Figure 17), the length 1593 of the retroreflector 5 can be made shorter than the length 1591 in Figure 15, allowing the entire image emitted from the display device 1 to be formed and displayed as a floating image 3. For comparison, points P and Pb are shown, and the point where the principal ray from the center of the image light emission surface of the display device 1 (point p0) enters the optical plate 150 changes from point P to point Pb. Therefore, the configuration in Figure 17, compared to Figure 15, allows for a shorter optical plate 150, resulting in a smaller floating image display device 1000, or in other words, preventing an increase in size. In addition, the configuration in Figure 17 allows for viewing at the luminance peak B1 when viewed from a user with a front view of the floating image 3, i.e., an observation direction BU with a downward angle of 45 degrees, and compared to Figure 16, the vertical viewing range is improved, allowing the entire screen of a sufficiently large size to be viewed.

[0260] [Angle range] In this embodiment 3, the tilt angle B of the floating image 3 will be explained using 65 degrees as the reference. This tilt angle B is, of course, not limited to 65 degrees. Any angle selected from the angle range of 65 degrees ± X is acceptable. If X is 10 degrees, this angle range is from 55 degrees to 75 degrees. More preferably, if X is 5 degrees, this angle range is from 60 degrees to 70 degrees. In principle, it is also possible to set this tilt angle B to an upper limit within the range of 75 degrees to 90 degrees. In this embodiment 3, based on experiments by the inventor, the tilt angle B that best displays the character image within the standing image 3A for multiple users was examined, and 65 degrees was selected as the tilt angle B. In this examination, a downward angle of 45 degrees was assumed as the reference observation direction and observation angle when observing the character image within the standing image 3A at tilt angle B from the user's viewpoint, and the display at various tilt angles B was compared. Then, when viewing the character image at that downward angle, we selected tilt angle B, which makes it easier to see / perceive the character as if it were standing on a horizontal plane.

[0261] Converting the above inclination angle B condition to the refraction angle C condition of the prism sheet 300, the range of refraction angle C can be any angle selected from the angle range of 20 degrees ± Y, with 20 degrees as the base. If Y is 10 degrees, this angle range is from 10 degrees to 30 degrees. More preferably, if Y is 5 degrees, this angle range is from 15 degrees to 25 degrees.

[0262] [Prism Sheet] Figure 18 shows an example configuration of the prism sheet 300 in Example 3 and also serves as an explanatory diagram of the operation and principle of the prism sheet 300. In Figure 18, a yz cross-sectional view is shown using (x,y,z) as the coordinate system based on the display device 1. In Figure 18, the display device 1 on which the prism sheet 300 is placed is referred to as display device 1B, and only a portion of the surface is schematically shown.

[0263] The prism sheet 300 is an optical component that refracts light. In other words, the prism sheet 300 may also be described as a linear prism sheet, prism plate, light guide, light guide component, light beam direction changing component, light beam direction changing sheet, or light beam direction conversion element. An example of a prism sheet implementation is the DTF series using a microprism array from Optical Solutions Co., Ltd. This product can be applied as the prism sheet 300 in this embodiment.

[0264] To cause the image light (ray 9020B1) emitted perpendicular to the display surface 1801 of the liquid crystal display panel 11 to be incident on the retroreflector 5 at an angle of α=45 degrees, as shown in Figure 17, a prism sheet 300, such as the one shown in Figure 18, is placed (for example, bonded) in close proximity to the display surface 1801, which is the image light emission surface of the liquid crystal display panel 11. The refraction angle C=20 degrees of the prism sheet 300 converts the image light (ray 9020B1) into image light (ray 9020B) refracted in a predetermined direction (direction of angle βB).

[0265] In the example configuration shown in Figure 18, the prism sheet 300 is placed on the outermost surface of the liquid crystal display panel 11. However, depending on the implementation, if another component exists on the outermost surface of the liquid crystal display panel 11, the prism sheet 300 may be placed on the surface of that other component.

[0266] As shown in Figure 18, the surface of the prism sheet 300 facing the display surface of the liquid crystal display panel 11 (the lower side in the z-axis direction, the side close to the display surface 1801) has a recessed portion 301 formed on it. The surface of the prism sheet 300 that has the recessed portion 301 is the surface facing the display surface 1801 of the liquid crystal display panel 11. In Example 3 (Figure 18), the recessed portion 301 consists of a zigzag-like or mountain-shaped groove 303 (in other words, a recess) having at least an inclined portion 302, which is repeated multiple times in the y-direction, which is the plane direction. The inclination of the inclined portion 302 is oblique with respect to the y-direction and z-direction. In other words, mountains 312 (in other words, convex portions) having an inclined portion 302 are formed multiple times in the y-direction. In other words, the shape of the recessed portion 301, in the illustrated example, is a shape in which convex portions or concave portions having a triangular wave shape with a right-angled triangular cross-section are repeated.

[0267] When light is transmitted through a prism sheet 300 of this shape, refraction of the light occurs, and when light (ray 9020B1) is incident on the inclined portion 302 of the groove 303 / ridge 312, light (ray 9020B) is emitted at a constant refraction angle C = 20 degrees. In the illustrated example, light emitted from the display surface 1801, for example, ray 9020B1, is incident on the ridge 312 from the side of the prism sheet 300 with the groove 303, is refraction at a refraction angle C (20 degrees) with respect to the normal of the display surface 1801, and is emitted as ray 9020B from the back surface (upper side in the z-axis direction) of the prism sheet 300 at an angle βB (70 degrees) with respect to the normal of the display surface 1801.

[0268] In Example 3, a light ray 9020B1 traveling perpendicularly from the display surface 1801 of the liquid crystal display panel 11 is refracted by the prism sheet 300 at a refraction angle C (20 degrees) and then emitted at an angle βB (70 degrees), thereby setting the incident angle α to the retroreflector 5 to 45 degrees. Therefore, the prism sheet 300 uses a device with a refractive index corresponding to a refraction angle C = 20 degrees. Note that in Figure 18, the focus is on the relationship between the incident and emitted light of the prism sheet 300, so the detailed behavior of light refraction and other phenomena inside the prism sheet 300 is omitted from the illustration.

[0269] [Spatial floating image display device of Example 3: Housing] Figure 19 shows a cross-sectional view (YZ plan view) of an example configuration of the spatial levitation image display device 1000 of Embodiment 3, which is composed of basic components such as the optical system shown in Figure 17. The display device 1B with a prism sheet 300 and the control board (in other words, the control device) 350 are housed and installed inside the housing 1190 of the spatial levitation image display device 1000. An optical plate 150 is installed on the top surface of the housing 1190 so as to be in the horizontal plane (XY plane). The three-dimensional shape of the housing 1190 is not limited; for example, it may be box-shaped or cylindrical as described later. The control board 350 has components such as the control unit 1110 shown in Figure 21, which will be described later, mounted on it as a system circuit. The display device 1B and the control board 350 are connected by a cable 360, which includes, for example, video signal transmission and power supply. Other components, such as a rechargeable battery, may be housed inside the housing 1190 as needed.

[0270] A housing 1190, as shown in Figure 19, is installed in the user's environment. The housing 1190 in Figure 19 is a horizontal housing 1190, with its top surface being a horizontal plane, and a standing image 3A is formed at an angle B = 65 degrees relative to this horizontal plane. The user observes and views the standing image 3A from the viewpoint position 232 at an oblique downward angle θB, for example, 45 degrees.

[0271] Furthermore, Figure 19 also illustrates an example configuration in which the imaging unit 1180 of Figure 3 is equipped with a camera 1180A, an aerial operation detection sensor 1351, a microphone 1139A for audio input, and a speaker 1140A for audio output. These components are also connected to the control board 350. The optical axis of the camera 1180A is directed, for example, towards the floating image 3 and the user, and can capture the state of aerial operations by the fingers 235 on the floating image 3, as well as the user's face. The optical axis of the aerial operation detection sensor 1351 is directed, for example, towards the plane of the floating image 3, and can detect the state of aerial operations by the fingers 235 on the floating image 3.

[0272] Although the prism sheet 300 was described as part of the display device 1B, it may also be considered as a component of the optical system. The prism sheet 300 may be placed in the optical path between the display device 1 and the retroreflector 5.

[0273] [Spatial floating image display device of Example 3: Cylindrical housing] Figure 20 shows an example of the external configuration when the shape of the housing 1190 is roughly cylindrical, based on Figure 19, in a perspective view taken from diagonally above. Housing 1190D shows a cylindrical housing. The cylindrical shape of this housing 1190D has a cylindrical axis that extends in the Z direction, which is the height direction, and a cylindrical diameter that extends in the X and Y directions, which are the directions of the horizontal plane perpendicular to the Z axis.

[0274] The top surface of the housing 1190D has an opening, or in other words, a transparent section, corresponding to the transparent member 100 of the optical plate 150. In this example, the shape of the opening / transparent section is circular, but it is not particularly limited and may be rectangular or other shapes. The top surface of the housing 1190D functions as a floor / stage for the standing image 3A, as the standing image 3A is positioned higher up.

[0275] The floating image 3, or standing image 3A, is formed with a predetermined inclination angle B of 65 degrees above the horizontal plane (XY plane) corresponding to the top surface of the housing 1190D. In this example, the display range 3R of the standing image 3A is a vertical screen, but it is not limited to this and could be a horizontal screen or other format.

[0276] The floating video display device 1000, having a cylindrical housing 1190D as shown in Figure 20, can be installed on any horizontal surface in the user's environment (e.g., a desk or table), and can also be stored in a bottle holder inside a vehicle, as described later. In other words, the housing 1190D can be stored inside an object having a cylindrical recess / hole. As this floating video display device 1000 can be realized using a retroreflective plate 5 with a reduced length as described above, it can be implemented and provided as a relatively small (compact) and portable floating video display device.

[0277] [Example 3 of the floating video display device: configuration of the control unit, etc.] Figure 21 shows an example configuration of the spatial floating image display device 1000 of Embodiment 3, including an example of the configuration of components such as the control unit 1110. Figure 21 is based on Figure 3, but the main difference is that a prism sheet 300 is provided behind the image display unit 1102 (liquid crystal display panel 11 in Figure 17) of the display device 1. Also, a real-time rendering unit 2160 is provided in accordance with one embodiment described later. Also, a switch button 2170 is provided in accordance with one embodiment described later. The switch button 2170 may be considered as part of the operation input unit 1107.

[0278] The real-time rendering unit 2160 generates video data to be displayed on the floating spatial image 3 by performing rendering processing in near real-time based on the source data and operation inputs related to the floating spatial image 3. The real-time rendering unit 2160 may be implemented as an integral part of the video control unit 1160 or the like. In one embodiment described later, if only pre-rendered preset video data is used, the real-time rendering unit 2160 can be omitted.

[0279] To explain the correspondence between the control board 350 in Figure 19 and Figure 21, the control board 350 is equipped with at least a control unit 1110, a video control unit 1160, an aerial operation detection unit 1350, or a real-time rendering unit 2160. Components such as the control unit 1110, video control unit 1160, aerial operation detection unit 1350, or real-time rendering unit 2160 may be referred to as the video processing unit. The display device 1 or the video display unit 1102 may be referred to as the display unit. The retroreflection unit 1101, etc., may be referred to as the optical system.

[0280] The example configuration shown in Figure 21 includes the components necessary to realize the features and functions described later. Here, we will explain some of the functions and operations, or just one example.

[0281] When the floating image display device 1000 displays a character image described later in the floating image 3, the image control unit 1160 generates display image data, or reads it from memory such as the storage unit 1170, and transfers it to the image display unit 1102. Based on the image data, the image display unit 1102 displays the image on the display surface of, for example, the liquid crystal display panel 11. Based on the image light of the image, the character image is displayed in the floating image 3A, which is the floating image 3, after passing through an optical system such as the retroreflection unit 1101.

[0282] Furthermore, the floating image display device 1000 of Embodiment 3 can change and switch the orientation (display depression angle, described later) of the character image when displaying the character image described later on the floating image 3, in response to the user's operation of the switch button 2170. The image control unit 1160, etc., selects and determines the orientation (display depression angle, described later) of the character image according to the operation status of the switch button 2170, generates or reads video data corresponding to that orientation from memory, and displays it on the floating image 3.

[0283] Regarding the posture of the character video described above (display angle of depression, as described later), in one embodiment described later, multiple video data of different postures with different display angles are prepared in advance by stereoscopic rendering processing on an external device (Figure 29). These video data are stored in advance as presets, for example, in the storage unit 1170. When in use, the video control unit 1160 reads the video data of the selected posture from the storage unit 1170 and transfers it to the video display unit 1102, thereby displaying the character video within the floating video 3.

[0284] Regarding the posture of the character video described above (display depression angle, as described later), in other embodiments described later, the real-time rendering unit 2160 generates video data of the selected posture by performing near real-time stereoscopic rendering processing on the original data and operation inputs. Then, the video control unit 1160 transfers this video data to the video display unit 1102, thereby displaying the character video within the floating spatial image 3.

[0285] Furthermore, in one embodiment described later, the angle adjustment mechanism 3700 (Figure 37) can adjust and change the arrangement angle of the housing 1190 (especially the retroreflective plate 5) and the floating image 3. In this case, the floating image display device 1000 detects the arrangement angle of the housing 1190 (especially the retroreflective plate 5) and the floating image 3 based on the angle sensor provided in the angle adjustment mechanism 3700 or the attitude sensor 1113 provided in the housing 1190. Then, according to the arrangement angle, the floating image display device 1000 can change the state of the character image in the floating image 3 (e.g., display depression angle) and display it using the image control unit 1160.

[0286] [Example of display from a comparative example spatial levitation image display device] Figure 22 shows an oblique view and a corresponding side view as an example of the display of the floating image 3 in the comparative example's floating image display device. This comparative example shows the display of the character image 2201 on the screen (display range 3R) of the floating image 3, which is formed with a tilt angle of 45 degrees to the horizontal plane and the optical plate 150 (stage surface 500), based on Figure 2D. This character image 2201 is an image of the character in an upright basic posture within the screen (display range 3R) of the floating image 3. When a user views such a character image 2201 of the floating image 3 from, for example, at a downward angle of 45 degrees, it may be difficult to see / perceive that the character is standing on the horizontal plane. It may also appear / perceive that the character is lying down relative to the horizontal plane.

[0287] As mentioned above, according to the specifications of the optical plate 150 including the retroreflector 5, the retroreflection efficiency is highest when the angle of incidence of the image light to the optical plate 150 is 45 degrees, based on the laws of physics. In other words, the luminance peak due to retroreflected light is highest when the angle of incidence is 45 degrees, and the luminance peak decreases as it moves away from 45 degrees. Therefore, it is necessary / desirable to set the angle of incidence of the image light to the optical plate 150 to around 45 degrees.

[0288] Furthermore, as mentioned above (Figures 15 and 16), when forming an upright image 3A with a tilt angle of 65 degrees, the incident angle deviates from 45 degrees, resulting in a lower brightness peak. When a user views this upright image 3A from the front, the downward angle becomes shallow at 25 degrees, and as a result, the floating image 3 appears dark. Also, in this case, as mentioned above, the retroreflector 5 becomes longer (Figure 15), or the size of the screen in the vertical direction becomes smaller (Figure 16).

[0289] [Example of display of the spatially floating image display device of Example 3] Therefore, in Embodiment 3, as shown in Figures 17 and 23, based on a predetermined hardware configuration, a standing image 3A, which is a floating image 3, is formed with a tilt angle B of 65 degrees relative to the horizontal surface of the housing 1190D and the upper surface (stage surface 500) of the optical plate 150. Furthermore, in Embodiment 3, a prism sheet 300 having a refraction angle C of 20 degrees is provided on the image light emission surface of the display device 1, so that the incidence angle and emission angle of the image light to the retroreflector 5 are set to α = 45 degrees. As a result, when the user observes the 65-degree standing image 3A (for example, display of character image 2301) at a downward angle of 45 degrees, an image with a luminance peak B1 can be provided, making it visible as a bright and suitable floating image 3. The downward angle of 25 degrees and the vertical field of view / viewing range relative to the luminance peak A1 as shown in Figure 16 can be changed to a downward angle of 45 degrees relative to the luminance peak B1 and a more expanded vertical field of view / viewing range relative to the luminance peak B1 as shown in Figure 17.

[0290] Figure 23 shows a perspective view and a corresponding side view as an example of the display of the floating image 3 in the floating image display device 1000 of Example 3. Figure 23 shows the case where the character image 2301 is displayed in the floating image 3, which is formed at a 65-degree angle to the stage surface 500 by the optical plate 150. The orientation of the character image 2301 within the screen of the floating image 3 is the same as the orientation of the character image 2201 in Figure 22. As a result, when the user views the character image 2301 at a downward angle of 45 degrees, the character appears / feels more likely to be standing on a horizontal plane (especially the stage surface 500) than in the comparative example.

[0291] Note that while Figures 22 and 23 illustrate the rectangular frame of the 3R display range for the floating spatial image 3 for illustrative purposes, this rectangle is not actually displayed. Furthermore, if you wish to present the 3R display range frame to the user in the floating spatial image 3, you can simply make the frame stand out using a specific color or other means.

[0292] [Rendering of character footage in a floating spatial image] Figure 24 is an explanatory diagram of rendering in a virtual 3D space when generating video data for displaying character images in the floating spatial image 3. When generating character images, a 3D object (in other words, a 3D model) of the character is placed in a computer's computational virtual 3D space, and a virtual camera is placed and set up. As part of the rendering process, the state / view of the 3D object captured by the virtual camera is generated as a character image / image on a 2D plane. In this embodiment 3, such rendering processing is performed in advance on the operator's computer, or by the real-time rendering unit 2160 (Figure 21) of the floating spatial image display device 1000. The floating spatial image display device 1000 drives and controls the display device 1 based on the rendered character image video data to display the character image on the display surface of the liquid crystal display panel 11. The video light corresponding to the displayed image forms the floating spatial image 3 through the optical system.

[0293] Figure 24 shows the yz-plane view in the coordinate system (x,y,z) of the virtual 3D space 2400. The horizontal axis (corresponding to the y-axis) in the virtual 3D space 2400 is shown as H. A 3D object (in other words, a 3D model) 2401 of a character is placed in the virtual 3D space 2400. The character's posture here is a basic upright standing posture. A virtual camera 2402 is set up for this 3D object 2401. The position, shooting direction (in other words, rendering display angle), and other parameter values ​​of the virtual camera 2402 are set. Figure 24 shows several examples of the settings for the virtual camera 2402.

[0294] Virtual camera C1 is set to capture the character's 3D object 2401 from the front, with the shooting direction being the y-direction and the elevation angle set to 0 degrees as the reference. This reference 0 degrees corresponds to the horizontal direction and the direction of the floor in the virtual 3D space 2400, and corresponds to the depth direction within the screen of the floating spatial image 3. Virtual camera C2 is set to capture the character's 3D object 2401 at a shallow angle downwards, with the shooting direction being a depression angle of 25 degrees. Virtual camera C3 is set to capture the character's 3D object 2401 at a shallow angle downwards, with the shooting direction being a depression angle of 45 degrees. Virtual camera C4 is set to capture the character's 3D object 2401 at a deep angle downwards, with the shooting direction being a depression angle of 65 degrees. These depression angles are just examples and can be set arbitrarily.

[0295] As shown in Figure 19, in this embodiment 3, from the user's viewpoint position corresponding to the reference observation position, a standing image 3A tilted at a 65-degree angle is observed with a downward-looking gaze and line of sight, at a downward-looking angle θB = 45 degrees, corresponding to the reference observation direction and reference observation angle. In this embodiment 3, the posture of the character image in the floating spatial image 3 is variably controlled based on this observation as the basis. The posture of the character image in the floating spatial image 3 (display downward angle described later, rendering display angle of the corresponding virtual camera 2402) can be changed according to the reference downward-looking angle θB. Specifically, as shown in Figure 24, by selecting the position and shooting direction (especially the downward angle) of the virtual camera 2402 during rendering, the standing posture at various display downward angles in the 2D image of the rendered character image can be variably set, as shown in Figure 25. To achieve a suitable viewing experience, the display angle of the character image (the rendering angle of the corresponding virtual camera 2402) should be selected to match the user's viewing angle θB to, for example, 45 degrees.

[0296] [Display angle of character video] Figure 25 shows examples of images displayed on the floating-space image 3, corresponding to the selection and change of the display angle of the character's standing posture. Figure 25 shows examples of character images obtained according to the shooting direction (angle of depression, rendering display angle) of the virtual camera 2402 in Figure 24. The top of Figure 25 shows the xz plan view when the 2D image of the character is viewed from the front, corresponding to when the floating-space image 3 screen is viewed from the front. Image 2501 is the character image / image corresponding to the virtual camera C1 at 0 degrees. Image 2502 is the character image / image corresponding to the virtual camera C2 at an angle of depression of 25 degrees. Image 2503 is the character image / image corresponding to the virtual camera C3 at an angle of depression of 45 degrees. Image 2504 is the character image / image corresponding to the virtual camera C4 at an angle of depression of 65 degrees. As shown in the examples in Figures 24 and 25, increasing the angle of depression of the virtual camera 2402 results in an image where the character is viewed from a higher, downward angle.

[0297] In this embodiment, as shown in Figure 25 and Figure 26 described later, the display depression angle of the object image (e.g., character image) is defined as the angle at which the object image tilts forward (in the -y direction in Figure 24) within the screen / image of the floating spatial image 3. This display depression angle is numerically the same as the depression angle (rendering display angle) of the shooting direction of the virtual camera 2402.

[0298] Figure 26 illustrates the concept of display depression angle in relation to Figure 25. In Figure 26, the coordinate system (x,y,z) of the floating spatial image 3 and the virtual 3D space 2400 are superimposed on the spatial coordinate system (X,Y,Z), and the tilt angle B of the standing image 3A is set to 65 degrees, illustrating the concept of the display depression angle of the character image 2601 within the standing image 3A. State A is a YZ plan view from the side, illustrating the concept of placing and displaying image 2501 with a depression angle of 0 degrees within the standing image 3A with a tilt angle B = 65 degrees in space. State B is a YZ plan view from the side, illustrating the concept of placing and displaying image 2502 with a depression angle of 25 degrees within the standing image 3A with a tilt angle B = 65 degrees in space. The display depression angle is D.

[0299] As in state A, image 2501, where the depression angle of virtual camera 2402 is 0 degrees, will have a display depression angle D of 0 degrees when the front direction of the character's standing posture (the horizontal plane in the virtual 3D space, the normal direction (y direction) of the screen of the floating spatial image 3) is set to 0 degrees. Similarly, the display depression angle D will be 0 degrees when the vertical direction (z direction) within the screen of the floating spatial image 3 is set to 0 degrees. As in state B, image 2502, where the depression angle of virtual camera 2402 is 25 degrees, will have a display depression angle D of 25 degrees when the front direction of the character's standing posture is set to 0 degrees. Similarly, the display depression angle D will be 25 degrees when the vertical direction within the screen of the floating spatial image 3 is set to 0 degrees. Within the screen of the floating spatial image 3, which corresponds to the image captured by the virtual camera, the standing posture of character image 2601 is tilted 25 degrees towards the viewer (-y) relative to the vertical direction (z-axis). This tilt corresponds to the display depression angle D of character image 2601. The same applies to image 2503, which has a depression angle of 45 degrees, and image 2504, which has a depression angle of 65 degrees.

[0300] The virtual floor surface 2610 shown in the diagram is a virtual floor surface on which the character image is assumed to be standing within the virtual three-dimensional space 2400, or in other words, within the floating spatial image 3.

[0301] In one embodiment, an image 2502 with a display depression angle D = 25 degrees is selected as the display depression angle for the character image displayed within a standing image 3A with an inclination angle B = 65 degrees. In this case, the result is as shown in state B. Due to the display depression angle D = 25 degrees, this character image appears to be standing on a virtual floor surface 2610 that coincides with the horizontal plane (horizontal axis H). In other words, this character image appears to have the front of the character's body facing horizontally.

[0302] As described above, one example is selecting and displaying image 2502 with a display depression angle D of 25 degrees, corresponding to a tilt angle B = 65 degrees and an observation angle θB = 45 degrees, but this is not the only option. The desired display depression angle D should be selected according to the design of the tilt angle B and observation angle θB. Alternatively, multiple display depression angles D may be provided as options, allowing the user to select their preferred display depression angle. In Figures 24 and 25, four values, including 0 degrees, are shown as examples for the angle and display depression angle of the virtual camera 2402, but this is not limited to these; multiple values ​​or continuous values ​​can be used.

[0303] As shown in the example above, in this embodiment 3, based on the hardware configuration of the floating image display device 1000 (Figure 17, etc.), the character image is displayed in a floating image 3 with a tilt angle B = 65 degrees relative to the horizontal axis. In addition, in this embodiment 3, the character image is displayed at a selected display depression angle D (in other words, a stereoscopic rendering display angle) of 25 degrees, for example, through the software configuration, particularly the stereoscopic rendering process. As a result, when the user views the character image in the standing image 3A, it is easier to see / perceive that the character is standing on a horizontal plane.

[0304] [Generating and displaying character images at the selected viewing angle] In this embodiment 3, one feature is that when displaying a character image on a screen of a standing image 3A with a tilt angle B of 65 degrees based on the hardware configuration shown in Figure 19, the following software processing is performed. That is, as shown up to Figure 26, the floating spatial image display device 1000 generates character image data so that the display depression angle D of the character image on the screen becomes a desired display depression angle (e.g., 25 degrees) selected in accordance with the tilt angle B and the reference observation angle θB, particularly based on rendering processing. Alternatively, the floating spatial image display device 1000 reads character image data at the selected desired display depression angle from preset image data. In this embodiment 3, character image data that has been rendered in advance to have a predetermined display depression angle is generated and stored in memory. When used by the user, it is only necessary to select and read the character image data from memory, and the rendering process can be omitted. In this case, the load on the computer's rendering process can be reduced, and a system using an inexpensive computer with low computing performance can be realized.

[0305] This third embodiment provides a configuration in which the display angle of the character image is set and changed according to the user's assumed reference viewing angle (and the vertical field of view centered on that reference viewing angle). This configuration may be implemented by fixing one reference viewing angle as the basic setting and fixing one suitable display angle corresponding to that reference viewing angle. Alternatively, it may be implemented by assuming multiple reference viewing angles and allowing the user to select and set a suitable display angle corresponding to each reference viewing angle. For example, the user may be able to select the reference viewing angle to be used from multiple viewing angles through user input or user settings. Then, a suitable display angle to match the selected viewing angle may be selected from multiple display angles and applied. Alternatively, the user may be able to select the display angle to be used from multiple display angles through user input or user settings.

[0306] In particular, the basic configuration of Example 3 involves the operator pre-defining several reference observation angles and display depression angles, and preparing and storing in memory as preset / default video data of character images rendered at each display depression angle. The floating video display device 1000 applies the display depression angle specified by the user settings or the like.

[0307] As a modification of Example 3, the floating image display device 1000 uses a real-time rendering unit 2160 (Figure 21) to generate a character image with a display depression angle selected to match the reference observation angle.

[0308] [Switching the display angle using physical buttons] In this embodiment 3, the user can select and use their desired display depression angle from a set of multiple display depression angles provided as options, based on user input. This input can be voice input, air control, or a pre-configured user setting. In particular, in this embodiment 3, the user can switch to a character image with one desired display depression angle selected from multiple types of display depression angles by pressing a physical switch button 2170 (Figure 21) provided on the housing 1190.

[0309] Figure 27 shows an example configuration in which a physical switch button 2170 (Figure 21) is provided on the housing 1190D. Pressing the switch button 2170 by the user enables switching of the display angle, for example, in a toggle (cycle) manner. State A is when the display angle of the character image 2701 in the floating spatial image 3 is 0 degrees, corresponding to image 2501 in Figure 25. Suppose the user wants to change the character image's posture. When the user presses the switch button 2170 once with their finger 235, the system transitions to state B. State B is when the display angle of the character image 2702 in the floating spatial image 3 is 25 degrees, corresponding to image 2502. When the user presses the switch button 2170 again, the system transitions to state C. State C is when the display angle of the character image 2703 in the floating spatial image 3 is 45 degrees, corresponding to image 2503. When the user presses switch button 2170 again, the system transitions to state D. State D is the state in which the display depression angle of the character image 2704 in the floating spatial image 3 is 65 degrees, and corresponds to image 2504. When the user presses switch button 2170 again, the system transitions back to state A.

[0310] This example demonstrates how to switch between four different display depression angles with the operation of a single button, but this is not the only possible approach. For example, a separate button could be provided for each display depression angle. Alternatively, buttons such as forward rotation and backward rotation buttons could be provided to continuously rotate the display depression angle forward and backward.

[0311] In this embodiment, we have described the case where a character image is displayed on the floating spatial image 3, but the above control of the display angle and other parameters can be similarly applied to any object image, especially object images generated by rendering based on a 3D model.

[0312] [Change the display angle based on user settings] In this embodiment 3, the user can also select and set a character image with a desired display angle through user settings. As a user setting function, a user setting screen may be provided in the floating image 3, allowing the user to select the display angle through user input (e.g., aerial operation).

[0313] Figure 28 shows an example of a GUI screen 2800 using a floating spatial image 3, which allows user setting of the display angle. In the user setting on the GUI screen 2800, a guide such as "Please select the character image's posture" is displayed, and a display angle selection button 2801 is displayed. The user can set the display angle by pressing the desired display angle selection button 2801 with, for example, an aerial operation using their fingers 235. A preview image 2802 at the display angle corresponding to the pressed selection button 2801 is also displayed. The display angle can also be set using a continuous numerical value. Furthermore, if the display angle is to be selected by voice input, the user can simply input, for example, "25 degrees" into the microphone.

[0314] The example in Figure 28 shows the setting of the display angle for a particular user and for a particular character video. Such user settings may be possible for each user and each character video. If user-specific settings are possible, user recognition is necessary. This can be done, for example, by photographing the user with the camera 1180A of the imaging unit 1180 in Figure 19 and performing facial recognition. Furthermore, it may be possible to select from multiple character videos used by the user, and settings such as posture may be possible for each character video.

[0315] [Selection of video data for preset display angle] In this embodiment 3, multiple character images corresponding to each of the multiple display angles may be generated in advance by rendering and stored in memory (for example, the storage unit 1170 in Figure 21). The multiple display angles are, for example, four values ​​as shown in Figure 25. When used by a user or when setting up the system, the user can select and switch between the desired character images from the multiple display angles according to user input, etc.

[0316] Figure 29 shows an example configuration of the floating spatial image display device 1000, where one image is selected and switched from multiple character image data at different display angles for display. An external device 2000, such as a business operator's PC or server, already contains a dataset 2013, including a 3D model 2001 that serves as the basis for the character image. The dataset 2013 may also contain motion information 2003, virtual light source information 2004, virtual camera information 2005, audio data 2006, and the like.

[0317] Prior to this, the video processing unit 2011 of the external device 2000 generates video data 2002 for displaying a 2D character image on the floating spatial image 3 (corresponding display unit 1502) by rendering the 3D model 2001. Video data 2902 corresponding to the video data 2002 is installed as preset video data in the memory of the floating spatial image display device 1000, such as the storage unit 1170 (Figure 21). Alternatively, the floating spatial image display device 1000 may download and acquire the video data 2002 or dataset 2013 from the external device 2000 via network communication as appropriate.

[0318] The video processing unit 1501 of the floating image display device 1000 drives and controls the display unit 1502 based on the video data 2902 corresponding to the video data 2002, thereby displaying an image for displaying the floating image 3 on the display surface of the display unit 1502, for example, the liquid crystal display panel 11. The floating image 3 is formed based on the image light from this image, which is adjusted via the optical system 1503 (for example, the retroreflector 5). The user operation detection mechanism 1504 is a mechanism for detecting aerial operations on the floating image 3, and corresponds to the aerial operation detection sensor 1351 and the imaging unit 1180 in Figure 21.

[0319] The video processing unit 1501 receives instruction information regarding the display depression angle based on user operation input via the operation input unit 1107 (including the aforementioned switch button 2170), detection information from the user operation detection mechanism 1504, or pre-configured user setting information 2903, etc. Based on the instruction information, the video processing unit 1501 selects and reads video data 2902 from memory that corresponds to the instructed display depression angle.

[0320] Figure 29 also illustrates the case where the floating spatial image display device 1000 holds the original data of the character image, such as the 3D model 2901. The floating spatial image display device 1000 may acquire the original data, such as the 3D model 2001, from an external device 2000 and store it as the 3D model 2901. In this case, the image processing unit 1501 (particularly the real-time rendering unit 2160 in Figure 21) may generate the image data 2902 by performing rendering processing in near real-time based on the 3D model 2901.

[0321] [Real-time rendering of the display angle] As described above, character images with preset display angles may be used, but in other configuration examples, the display angle may be a continuous value within a predetermined range, and a character image at a selected display angle may be generated and displayed by near real-time rendering processing. There are various ways to determine the display angle, for example, the user may directly specify the numerical value of the display angle through user input or user settings. Alternatively, even without user specification, the floating image display device 1000 may detect / estimate a reference observation angle, etc., and automatically determine a suitable display angle based on the detected / estimated value. In the latter case, for example, the image processing unit 1501 estimates and calculates the user's actual viewpoint position (e.g., the center point of both eyes) from the captured image taken near the user's face by the camera of the imaging unit 1180. The image processing unit 1501 estimates and calculates the observation angle (angle of depression) corresponding to the calculated viewpoint position. The video processing unit 1501 then determines a suitable display depression angle to match the observation angle. For example, if the detected / estimated observation angle is 50 degrees, which is 5 degrees greater than the reference 45 degrees, the video processing unit 1501 may determine it as 30 degrees, which is 5 degrees greater than the reference display depression angle of 25 degrees. The video processing unit 1501 generates video data 2902 that matches the determined display depression angle from the 3D model 2901 through rendering processing by the real-time rendering unit 2160 (Figure 21).

[0322] [Elevation angle of the character's face in the video] In this embodiment 3, when displaying a character image on the floating spatial image 3, in addition to controlling the downward angle of the display, the upward angle of the character's face may also be controlled so that the character's face faces towards the user's viewpoint.

[0323] Figure 30 is an explanatory diagram illustrating an example of displaying a character image in the floating spatial image 3, where the display elevation angle of the character's face is controlled so that the character's face faces towards the user's viewpoint. This display elevation angle is such that the character's face looks upwards towards the user. Setting and changing this display elevation angle is achieved through software processing of the video data, particularly rendering.

[0324] First, as a prerequisite, there is control over the basic standing posture and display angle of the character image, as shown in Figure 25 above. Then, the video processing unit 1501 (Figure 29) controls the display elevation angle of the face portion within the floating spatial image 3 so that the face of the character image faces in a direction close to the observation angle θB, in accordance with the user's observation angle θB.

[0325] In this embodiment 3, first, an idling state for the character image is set as the first control state / display state. The idling state is the state when there is no predetermined action from the user towards the character image, and the state when the character image is not responding to the user. In the first display state, for example, the standing posture of the character image is set to a predetermined display downward angle posture in Figure 25. Here, for example, assuming an observation angle θB = 45 degrees, the standing posture is set to a display downward angle = 25 degrees, as shown in Image 2502. This standing posture appears to be standing at a 90-degree angle to the horizontal plane.

[0326] Figure 30 also shows examples related to the idling state, etc. State A is the idling state of the character image as the first control state / display state. The character image 3001 is displayed in a standing position with a display depression angle of 25 degrees, similar to image 2502 in Figure 25. In the idling state, the character image may be still, or it may be performing a predetermined movement. In the idling state, predetermined messages or sounds may be output. In the idling state, for example, the image may show the character sleeping.

[0327] The floating video display device 1000 accepts predetermined user actions (first actions) such as voice input, aerial operation, and physical button operation in an idling state. State B is the state of the user action. For example, when using aerial operation, the user may touch the screen of the floating video 3 with their finger 235. For example, the aerial operation detection sensor 1351 (which may be an electrostatic sensor, infrared sensor, distance sensor, camera, etc.) in Figure 21 detects this touch operation. Alternatively, detection of pressing a predetermined physical button may also be used. The video processing unit 1501 (Figure 29) inputs and receives such operation input information or detection information. In the case of voice input, detection of a predetermined wake-up keyword in voice may also be used.

[0328] The trigger for a predetermined action, in other words, for transitioning from the idling state to the next second control state, may be an action by the user, or it may be when a predetermined amount of time has elapsed or a predetermined time has arrived. Alternatively, this trigger may be when the imaging unit 1180 or other human presence sensors detect that the user has approached the floating image display device 1000 within a certain distance.

[0329] When the floating spatial image display device 1000 detects a predetermined action by the user, in other words, when a predetermined condition is met, it transitions the character image in the floating spatial image 3 to a second control state / display state. The second display state is a state in which the character's face reacts to the user and changes the character's face to a predetermined display elevation angle. At this time, it is assumed that the user is viewing the character image in a line of sight direction corresponding to a predetermined reference observation angle θB (for example, a downward angle of 45 degrees).

[0330] State C is a second control state / display state in which the character's face is looking up at the user at a predetermined display elevation angle (in other words, a reaction state) (this also corresponds to state B in Figure 31, described later). Here, for example, the character's body, such as the torso and legs, is drawn based on a display depression angle of 25 degrees, the same as in the idling state, while the display content of the part including the face is changed so that it faces the user's face / viewpoint at a depression angle of 45 degrees at the selected display elevation angle. The display elevation angle here is 45 degrees with respect to the horizontal plane, as shown in state B in Figure 31.

[0331] The video processing unit 1501 uses video data to display a character image in which the character's face is looking diagonally upward at the selected display elevation angle. Similar to the control of the display depression angle described above, this video data is prepared in advance as a preset, with multiple video data corresponding to multiple display elevation angles to be selected and read. Alternatively, as described above, the character image at the selected desired display elevation angle may be generated by rendering in near real-time when in use.

[0332] The user views the character image of the floating spatial image 3 with the above-mentioned elevation angle at a reference observation angle (e.g., a downward angle of 45 degrees). This makes the user feel as if the character is reacting to their actions and turning towards them. According to this embodiment, it is possible to provide a floating spatial image that is both three-dimensional and highly interactive.

[0333] Furthermore, in the second control state / display state of Figure 30, the character image may be displayed facing the user as described above, and a predetermined response may be displayed. The response may be, for example, a predetermined message (e.g., "Hello," "What would you like to do?", "What would you like to know?") or GUI displayed on the floating image 3, or audio output may be provided. During the response time in the second control state, the user may further input operations (e.g., selections or questions) to the character or GUI.

[0334] For example, screen 3003 of the floating spatial image 3 in state D shows an example of a response display. On this screen 3003, a message from the character image 3002 at the display elevation angle ("Please select," etc.) is displayed, and selection buttons are shown. The user can select the desired selection button. The floating spatial image display device 1000 then performs predetermined processing in response to the user's operation input. For example, if this floating spatial image 3 is used as the GUI for an in-vehicle system, guidance and instruction input regarding the functions of the in-vehicle system using the character image can be realized.

[0335] In another use case, if this floating video display device 1000 is installed at a facility's reception desk, the floating video 3 may display the GUI and guides of the reception desk along with the character video.

[0336] Furthermore, in the second control state, when a predetermined condition is met, such as when a predetermined response is completed, the floating spatial image display device 1000 controls the display of the character image of the floating spatial image 3 to return to the first control state, which is the idling state. The predetermined condition may be, for example, when a predetermined time has elapsed since the detection of the first action, or when a predetermined second action is detected.

[0337] Regarding the face display elevation angle function described above, for example, similar to Figure 28, the user may be able to set their desired display elevation angle on the user settings screen. Alternatively, similar to Figure 27, the face display elevation angle may be switched in response to the operation of a physical button.

[0338] Figure 31, in relation to Figure 30, is an explanatory diagram regarding the display elevation angle of the face, illustrating the state of the character in the virtual 3D space 2400 and providing examples of character images corresponding to a front view of the standing figure 3A. State A is the case where the display depression angle of the basic upright standing posture is 45 degrees, and the shooting direction (depression angle) by the virtual camera C3 is 45 degrees. The user's reference observation angle θB is a depression angle of 45 degrees. Image 2503 on the right is the character image corresponding to the display depression angle = 45 degrees as described above (Figure 25).

[0339] In character 3101, the face portion 3102 includes the face 3103, neck, chest, and shoulders. The face 3103 of character 3101 faces forward at 0 degrees relative to the horizontal axis H in the virtual 3D space 2400, and this is referred to as the direction 3104 of the face 3103. Based on this state, the display elevation angle E = 0 degrees.

[0340] State B shows the case where the display elevation angle E of the face portion 3102 of character 3106 is changed to display elevation angle E=45 degrees to match the reference observation angle of downward angle of 45 degrees. Image 2523 on the right is an image of the character with a display downward angle D=45 degrees and a display elevation angle E=45 degrees. The torso and other body parts of character 3106 are in roughly the same state as character 3101, but the face portion 3102 has changed to bend backward. The direction 3104 of face 3103 is facing 45 degrees diagonally upward with respect to the horizontal axis H, corresponding to the user's downward angle of 45 degrees and display elevation angle E=45 degrees.

[0341] Note that the displayed elevation angle E here is defined as the angle with respect to the horizontal axis H in the virtual 3D space 2400. However, similar to Figure 26, the displayed elevation angle E of the character's face in a standing figure 3A with an inclination angle B can be calculated as, for example, the angle at which the face portion 3102 is tilted relative to the direction of the basic standing posture (for example, axis 2620 in Figure 26).

[0342] Figure 32 shows several examples of face elevation angles E, with side views of characters in a virtual 3D space. Character 3201 has a face elevation angle E of 0 degrees relative to the horizontal plane (y-axis). Character 3202 has a face elevation angle E of 25 degrees relative to the horizontal plane. Character 3203 has a face elevation angle E of 45 degrees relative to the horizontal plane. Character 3204 has a face elevation angle E of 65 degrees relative to the horizontal plane. Character 3203 corresponds to image 2523 in Figure 31.

[0343] For example, the video processing unit 1501 (Figure 15) receives instruction information or selection signals regarding the display elevation angle E of the face and determines the display elevation angle E to be used. Alternatively, the video processing unit 1501 determines the display elevation angle E to be used based on a predetermined judgment. For example, when a selection signal is input to select one of the multiple display elevation angles shown in Figure 32, the video processing unit 1501 controls the display of the character image in the floating spatial image 3 so that the display elevation angle E corresponds to that selection signal. That is, the video processing unit 1501 generates a character image at the selected display elevation angle E using preset video data or real-time rendering.

[0344] For example, when using a preset, character 3201 with a display elevation angle E of 0 degrees is selected during the idling state (Figure 30) as described above. Also, when responding to an action, for example, character 3202 is selected for a 25-degree selection signal. For a 45-degree selection signal, character 3203 is selected. For a 65-degree selection signal, character 3204 is selected. Alternatively, as described above, when the display elevation angle is automatically determined by inferring the user's observation angle, for example, if the observation angle is a downward angle of 50 degrees, the display elevation angle of the face may be determined to be 50 degrees.

[0345] [How the character images look] Figure 33 shows an oblique view and a side view as explanatory diagrams regarding the subjective appearance when viewing a character image of a standing figure 3A with a downward angle of 45 degrees and an inclination angle B=65 degrees from the user's viewpoint, based on the configurations of Figures 20, 23, and 25. A standing figure 3A, which is a floating image 3, is formed at 65 degrees relative to the upper surface (stage surface 500) of the optical plate 150 of the floating image display device 1000, and a character image 3301 is displayed within the standing figure 3A with its display downward angle controlled to, for example, 25 degrees. The user observes this character image 3301 with an downward angle of 45 degrees as the observation angle θB. As a result, as shown in the oblique view, the character appears / feels like it is standing on a horizontal plane (especially the stage surface 500) from the user's perspective.

[0346] [Comparative example: Vertical field of view when the observation angle deviates from the standard] In the embodiments described so far, we have explained a configuration example in which the optical plate 150 including the retroreflector 5 is placed on a horizontal plane, the tilt of the upright image 3A is 65 degrees, and the user observes with a downward angle of 45 degrees as the reference observation angle. However, in actual usage environments and situations, as shown in Figure 34, the observation angle from the user's viewpoint may fall outside the suitable angle range of 45 degrees ± X.

[0347] Figure 34 shows the optical system of a comparative example of a floating image display device. Based on the embodiment in Figure 17, Figure 34 shows a specific example where the user's observation angle θB deviates from the reference observation angle of 45 degrees, specifically a shallower angle, θ1 = approximately 30 degrees. The observation angle θB (45 degrees) from viewpoint position 3400 changes to the observation angle θ1 from viewpoint position 3401, which is the angle θ1.

[0348] In this comparative example, similar to Figure 17, the optical plate 150 including the retroreflector 5 is arranged in the horizontal plane (horizontal axis H). The display device 1B is positioned at a 65-degree angle to the optical plate 150, and the upright image 3A is formed at a 65-degree angle to the optical plate 150. The length of the optical plate 150 in the depth direction (Y direction) is PL1.

[0349] The principal ray from the center (point Ct2) of the display surface of the liquid crystal display panel 11 of the display device 1B is refracted by the prism sheet 300 (refraction angle C=20 degrees as described above), incident on the optical plate 150 at an incident angle α=45 degrees to point P, and is imaged at the center (point Ct1) of the upright image 3A by retroreflected light from point P at an exit angle α=45 degrees. The ray emitted from the upper end (point Tp2) of the display surface is incident on point Q near the front end of the optical plate 150, and retroreflected light is imaged at the lower end (point Bt1) of the upright image 3A. The ray emitted from the lower end (point Bt2) of the display surface is incident on point R near the rear end of the optical plate 150, and retroreflected light is imaged at the upper end (point Tp1) of the upright image 3A. When a user observes the standing image 3A from a viewpoint position 3400 at a downward angle of 45 degrees, which is the reference observation angle θB, the entire upper and lower range of the image 3A can be viewed favorably.

[0350] In contrast, when a user observes the standing image 3A from viewpoint position 3401 at an observation angle θ1, which is approximately a 30-degree downward angle, the following occurs. We consider the line of sight direction 3402, which is the view from viewpoint position 3401 to the center of the standing image 3A (point Ct1), as the reference. In the direction from the center of the screen of the standing image 3A (point Ct1) toward the optical plate 150, and in the direction from the lower end (point Bt1) toward the optical plate 150, the corresponding points on the plane of the optical plate 150 are reached, and the corresponding images can be seen. However, in the direction 3403 from the upper end of the screen of the standing image 3A (point Tp1) toward the optical plate 150, the optical plate 150 is not reached, and a point S where the optical plate 150 is not present is reached. In the direction 3404 from a point T on the standing image 3A, the point R at the rear end of the optical plate 150 is reached.

[0351] Therefore, when viewed from viewpoint position 3401, in the range 3420 from point T to the bottom edge (point Bt1) on the screen of the upright image 3A, the image is visible, or an image with reduced brightness is visible compared to when viewed from viewpoint 3400. However, in the range 3410 from point T to the top edge (point Tp1) on the screen of the upright image 3A, the image is not visible, or only an image with reduced brightness is visible compared to when viewed from viewpoint 3400.

[0352] Range OR1 is a horizontal plane range corresponding to the range 3410 of the image 3A, and there is no corresponding plane on the optical plate 150. When observing the image 3A from viewpoint 3401 at a depression angle θ1, the portion of the image within range 3410 will be cut off from view; in other words, part of the image on the screen will not be displayed or visible. In other words, the field of view / viewing range in which the image can be viewed normally, corresponding to the vertical direction (z-axis) of the image 3A, is limited to the portion 3420 excluding range 3410.

[0353] As shown in the comparative example above, assuming a range of reference observation angles, if the actual user's viewpoint position and observation direction fall within these criteria, that is, if the downward angle is within the range of 45 degrees ± X degrees, the entire upper and lower range of the standing image 3A can be seen. However, if the actual user's viewpoint position and observation direction deviate from the criteria, that is, if it is outside the range of 45 degrees ± X degrees, then, as in the example above, a part of the standing image 3A cannot be seen, and the effective upper and lower field of view / viewing range is narrowed.

[0354] As described above, in cases where a portion of the image on the screen of the standing image 3A is not visible to the user (screen cropping), one embodiment may be configured as shown in Figure 35.

[0355] [Example of tilted optical plate arrangement] Figure 35 is a YZ plan view showing the optical system, etc., of a spatial levitation image display device 1000 according to one embodiment. In the embodiment shown in Figure 35, the observation angle from the user's viewpoint is assumed to be an observation angle θ1 that deviates from the reference observation angle (downward angle of 45 degrees), similar to Figure 34. In other words, in the embodiment shown in Figure 35, this observation angle θ1 can be considered as a new reference observation angle. This observation angle θ1 is the angle that is expected in the environment and situation in which the user actually uses the spatial levitation image display device 1000.

[0356] Furthermore, in this embodiment, the optical plate 150 is positioned at a predetermined angle (denoted as γ) from the horizontal plane (horizontal axis H). In this embodiment, the predetermined angle γ is 10 degrees. This inclination at angle γ means that, in the Y direction corresponding to the horizontal axis H shown in the figure, the rear (+Y) end of the optical plate 150 is raised upward (+Z) relative to the front (-Y) end; in other words, it is a downward rotation of the optical plate 150 around the X axis. The length PL1 of the optical plate 150 remains unchanged from that shown in Figure 34.

[0357] In this embodiment, the tilt angle B of the floating image 3 is maintained at 65 degrees with respect to the horizontal plane, the same as in the previous embodiment (Figure 17). To achieve this, the angle of the floating image 3 with respect to the optical plate 150 is (65 degrees - γ) = 55 degrees. Correspondingly, the display device 1B is positioned symmetrically with respect to the optical plate 150, so the angle with respect to the optical plate 150 is 55 degrees, and the angle with respect to the horizontal plane is (55 degrees - γ) = 45 degrees. The relationship between the display device 1B and the optical plate 150 is maintained in the same way as in Figure 17, using a prism sheet 300 to set the incident angle α to 45 degrees, resulting in an arrangement that is rotated by 10 degrees overall from Figure 17. Also, the refraction angle of the prism sheet 300 in Figure 35 should be C = 10 degrees in order to set the incident angle α to 45 degrees.

[0358] In Figure 35, when the user observes the floating image 3 at an observation angle θ1, the direction 3403 passing through the top edge of the screen (point Tp1) reaches point R at the rear end (left edge in the drawing) of the optical plate 150. This direction 3403 has corresponding incident and outgoing image light. As a result, when the user observes the floating image 3 at an observation angle θ1, the top of the floating image 3 is not cut off, and the entire upper and lower range of the screen is visible, expanding the effective vertical field of view / viewing range compared to the case in Figure 34.

[0359] The configuration example in Figure 35 assumes use at a depression angle θ1 and fixes the optical plate 150 at an inclination of γ = 10 degrees. The inclination angle γ of the optical plate 150 is not limited to 10 degrees. The angle γ may be within the range of 10 degrees ± Z, for example, within the range of 10 degrees ± 5 degrees. If this angle γ is increased to, for example, 15 degrees or 20 degrees, the vertical viewing range will increase accordingly. However, from the user's perspective, the optical plate 150 may appear / feel like the floor surface on which the character image in the standing image 3A is standing. Therefore, if the optical plate 150, which acts as the floor surface, is tilted too much from the horizontal, it will appear / feel like the character is standing on a slanted surface, which may cause discomfort to some users, and the effect of the character appearing to be standing on a horizontal surface will be reduced. Therefore, in this embodiment, a balance was struck between the user's observation angle θ1, the size of the vertical viewing range, and the effect of making the character image of the standing figure 3A appear to be standing, and the angle γ was designed to be 10 degrees ± 5 degrees.

[0360] [Modified example: Addition of a transparent plate] Figure 36 shows a modified configuration of Figure 35. The main difference between this modified configuration and Figure 35 is that the transparent member 100 of the optical plate 150 is removed, and a transparent plate 3600 is placed horizontally above the retroreflective plate 5. This transparent plate 3600 may be the same as the transparent member 100, or it may be a different material. The transparent plate 3600 may be placed above the optical plate 150, which consists of the transparent member 100 and the retroreflective plate 5. This transparent plate 3600 is a device that transmits image light. When a user views the standing image 3A, it is easy to perceive it as if the transparent plate 3600 placed on the horizontal plane is the floor, and the character image is standing on that horizontal floor.

[0361] Furthermore, based on the configuration shown in Figure 35, it is also possible to configure the optical plate 150 so that its tilt angle is variable rather than fixed, as shown below.

[0362] <Example 4> The floating image display device of Embodiment 4 will now be described. Figure 37 shows an example configuration of the floating image display device 1000 of Embodiment 4. Based on the configuration of Figure 35, Embodiment 4 has a configuration in which the tilt angle of the optical plate 150 can be set to be variable rather than fixed by the angle adjustment mechanism 3700. Furthermore, the floating image display device 1000 of Embodiment 4 has a housing structure that can be housed and mounted in a cylindrical structure such as a car-mounted bottle holder (in other words, a cup holder or drink holder).

[0363] Depending on the environment and circumstances in which the user uses the floating image display device 1000 (e.g., inside a vehicle), the positional relationship between the user's viewpoint and the floating image 3 may differ. For example, this positional relationship arises depending on the user's height and sitting height, head position and orientation, and the position and orientation of the bottle holder in which the floating image display device 1000 is housed. Depending on this positional relationship, the aforementioned observation angle and vertical field of view may change. For example, the placement of bottle holders inside a vehicle can vary, such as being near the air conditioner or near the gear shift lever.

[0364] Therefore, in Embodiment 4, a mechanism is provided, through hardware and software configurations, to adjust the arrangement of the standing image 3A and the display content of the character image, so as to accommodate observation angles that vary depending on the positional relationship. Specifically, in Embodiment 4, an angle adjustment mechanism 3700 is provided on the housing 1190. In other words, the angle adjustment mechanism 3700 is a swivel mechanism, which is a mechanism that can rotate forward and backward in the depth direction (Y direction) around a predetermined axis 3731 (X-axis). This angle adjustment mechanism 3700 allows the orientation and position of the floating image 3, which is the standing image 3A, to be adjusted to match the user's observation angle. The angle adjustment mechanism 3700 allows the angle of the arrangement of the entire system, including the display device 1B, the optical plate 150, and the floating image 3, to be adjusted.

[0365] In this embodiment 4, the user can adjust and set the angle of the angle adjustment mechanism 3700 (in other words, the swivel angle, rotation angle) by manually moving the housing 1190 (especially the upper housing 1190B) back and forth. This swivel angle may be variable in a continuous range or in several steps. In this embodiment 4, a predetermined set of multiple swivel angles is defined and prepared in advance. Preset video data is also prepared for each angle to match the swivel angle. Furthermore, the user can adjust and set the orientation of the character image as the display content of the standing figure 3A (such as the display depression angle mentioned above). This enables increased efficiency and lower costs.

[0366] The embodiments shown from Figure 37 onward illustrate configurations that can be mounted in a vehicle's bottle holder. The embodiments shown before Figure 37 can be used in various environments, not limited to mounting in a bottle holder.

[0367] [A housing and swivel mechanism that can be mounted in a bottle holder] In Figure 37, the housing 1190 in Embodiment 4 is broadly composed of a lower housing 1190A and an upper housing 1190B, which are mechanically connected via an angle adjustment mechanism 3700. The lower housing 1190A is a part that can be housed within a cylindrical bottle holder 3750 (only a portion is schematically shown), and has a predetermined holding mechanism, etc., and is held in place by the bottle holder. In other words, the lower housing 1190A is a bottle holder mounting mechanism. The upper housing 1190B rotates back and forth in the depth direction (Y direction) around the shaft portion 3731 relative to the lower housing 1190A by the angle adjustment mechanism 3700, allowing the positioning angle (swivel angle) to be adjusted. The upper housing 1190B is held stationary in a selected positioning angle (swivel angle). The positioning angle (swivel angle) of the upper housing 1190B can be changed by the user's manual operation of the angle adjustment mechanism 3700 and the upper housing 1190B.

[0368] The arrangement of the upper housing 1190B in Figure 37 is based on Figure 35, with the optical plate 150 tilted at γ = 10 degrees with respect to the horizontal plane (horizontal axis H). The swivel angle in the arrangement shown in Figure 37 is set to 0 degrees, with the basic angle R1. The arrangement in Figure 37 is considered the first state, or basic state. The swivel angle by the angle adjustment mechanism 3700 is set to R1 = 0 degrees, with the position of the dashed line shown as the base.

[0369] In this basic state, the floating image 3, the standing image 3A, is positioned at an inclination angle B of 65 degrees with respect to the horizontal plane (horizontal axis H). The character image 3701 within the standing image 3A can similarly be controlled, for example, by the aforementioned control of the display depression angle and the display elevation angle of the face. Let θ1 be the user's observation angle assumed to correspond to the first state in Figure 37. The observation angle θ1 is the same as θ1 in Figure 35, for example, about 30 degrees. The floating image display device 1000 controls the display of the character image 3701 of the standing image 3A in accordance with this first state (R1=0 degrees). As an example of such display control, the character image 3701 is displayed at a selected display depression angle of 25 degrees (image 2502 in Figure 25).

[0370] In the configuration example shown in Figure 37, the upper housing 1190B also houses a control board 3710 in addition to the display device 1B. The control board 3710 corresponds to the control board 350 in Figure 19 and is the component corresponding to the control unit 1110 in Figure 21 and the video processing unit 1501 in Figure 29. The system circuit on the control board 3710 performs processing such as controlling the idling and response display operations described above (Figure 30) as standalone operation of the character image 3701 of the standing image 3A.

[0371] In the first state shown in Figure 37, the character image 3701 within the standing figure 3A is displayed in a posture that appears to be standing in the vertical direction 3702 (vertical axis, Z direction, basic posture angle, etc.) by controlling the display depression angle. When the upper surface of the optical plate 150 is considered as the stage surface 500, the positional angle of the standing posture of the character image 3701 is, with respect to this vertical direction 3702 as the reference, 90 degrees + γ to 100 degrees relative to the front side of the stage surface 500 (if the angle is φ1), and 90 degrees - γ, or 55 degrees + 25 degrees to 80 degrees relative to the rear side of the stage surface 500.

[0372] The tilt angle γ of the optical plate 150 on the stage surface 500 is relatively small at 10 degrees, and since the optical plate 150 is light-transmitting, this tilt is not very noticeable to the user, and it is generally perceived as a horizontal plane. Therefore, when the user observes the character image 3701 of the standing image 3A at an observation angle θ1, the character is generally perceived as standing on a horizontal plane. Note that the basic posture angle controlled by the display depression angle is not limited to 25 degrees and can be selected by the user. For example, if the display depression angle is set to 35 degrees, the basic posture angle will be tilted 10 degrees forward from the vertical direction 3702. In that case, the basic posture angle will be 90 degrees relative to the stage surface 500. If the user wishes to set the angle relative to the stage surface 500 to 90 degrees, such control can also be applied.

[0373] In Figure 37, the lower housing 1190A has a mounting portion 3730 that is housed in a cylindrical hole 3751 of the vehicle's bottle holder 3750. The mounting portion 3730 has a shaft portion 3731 (in other words, a hinge portion) that constitutes the angle adjustment mechanism 3700. The shaft portion 3731 extends in the X direction and is connected to a bearing which is part of the upper housing 1190B. The mounting portion 3730 may also be equipped with an angle sensor 3760 for detecting the rotation angle state of the angle adjustment mechanism 3700. Alternatively, the upper housing 1190B may be equipped with an attitude sensor 1113 (Figure 21).

[0374] The upper housing 1190B has a housing 3740 that widens towards the top in the Z-axis direction, as shown in the figure, so that it can be rotated and tilted forward and backward by the angle adjustment mechanism 3700. The detailed shape of housing 3740 is not particularly limited. An optical plate 150 with the aforementioned inclination is installed on the top surface of housing 3740, and the display device 1B and control board 3710 are mounted inside housing 3740. In the first state of Figure 37, the upper housing 1190B is positioned along the vertical direction (Z-axis direction) as indicated by the dashed line that shows the reference line (swing angle R1). Near this reference line is a point P where the principal ray of the center of the image light on the optical plate 150 enters and exits.

[0375] The angle adjustment mechanism 3700 is a mechanism in which the upper housing 1190B rotates back and forth around the shaft portion 3731 and can maintain a stable stationary state at each of several predetermined angles within a predetermined angle range. By adjusting the swivel angle of the angle adjustment mechanism 3700, the positioning angle of the optical plate 150 and the upright image 3A can be adjusted to the user's desired angle selected within a predetermined range. This embodiment 4 describes a case in which three preset angles and three stages of angles can be selected (Figures 37 to 39).

[0376] The part shown as bottle holder 3750 may be a receiving part of an actual bottle holder. Figure 40 shows an example of such a bottle holder as a modified example. The receiving part 3750b in Figure 40 is held inside the cylindrical side surface of the opening of bottle holder 3750c. The mounting part 3730 is housed and held in the hole 3751 of this receiving part 3750b. This receiving part 3750b may be part of the bottle holder, or it may be part of the floating image display device 1000 (especially the lower housing 1190A). As will be described later, there are various specifications such as the diameter of the bottle holder, so it is more preferable to provide a mechanism in the lower housing 1190A that can accommodate and mount the floating image display device 1000 according to various specifications.

[0377] In addition, in the configurations shown in Figures 19 and 37, it is also possible to provide terminals etc. as input / output interfaces on the housing 1190, and connect the control board 350 / control board 3710 and other input / output devices to the outside of the housing 1190.

[0378] Figure 38 shows an example of a different arrangement angle of the upper housing 1190B with a different swivel angle (let's call it R2) compared to Figure 37, specifically a state where it is tilted forward. For example, if a user manually tilts the upper housing 1190B forward in the Y-axis direction, the angle adjustment mechanism 3700 can bring it to the state shown in Figure 38. The state in Figure 38 is referred to as the second state, the forward-tilted state. In the second state, the angle R2 set by the angle adjustment mechanism 3700 is approximately 20 degrees forward compared to the first state. The arrangement of the display device 1B and other components inside the upper housing 1190B remains constant. In the second state, the tilt of the optical plate 150 is approximately γ+R2=30 degrees with respect to the horizontal axis H. Also, the tilt angle of the standing image 3A is approximately 65 degrees+R2, or γ+R2+55 degrees to 85 degrees with respect to the horizontal axis H, roughly close to vertical.

[0379] Let θ1B be the user's assumed observation angle corresponding to the second state in Figure 38. The observation angle θ1B may differ from the observation angle θ1 in Figure 37, but here we assume θ1B = θ1 = approximately 30 degrees. Let the user's viewpoint position be viewpoint position 3501B. The viewpoint position 3501B may differ from the viewpoint position 3501 in Figure 37. The floating spatial image display device 1000 controls the display of the standing character image 3801 in accordance with this second state. As an example of this display control, the character image 3801 is displayed at a selected display depression angle D. Here, the display depression angle D is, for example, approximately 5 degrees. In this case, as shown in the figure, the basic posture angle of the character becomes close to the vertical direction 3702. Also, the positioning angle of the standing posture of the character image 3801 is approximately 90 degrees + γ + R2 to 120 degrees relative to the front side of the stage surface 500, assuming an angle φ2.

[0380] Figure 39 shows an example of a different positioning angle for the upper housing 1190B with a different swivel angle (let's call it R3) compared to Figure 37, specifically a state where it is tilted backward. For example, if a user manually tilts the upper housing 1190B backward in the Y-axis direction, the angle adjustment mechanism 3700 can bring it to the state shown in Figure 39. This state in Figure 39 is referred to as the third state, the backward tilt state. In the third state, the angle R3 set by the angle adjustment mechanism 3700 is approximately 20 degrees backward compared to the first state. In the third state, the tilt of the optical plate 150 is approximately γ-R3 = -10 degrees with respect to the horizontal axis H. This tilt means that the rear end of the optical plate 150 is lower than the front end. The tilt angle of the standing image 3A is approximately 45 degrees, ranging from 65 degrees-R3 or γ-R3+55 degrees, with respect to the horizontal axis H.

[0381] Let θ1C be the user's assumed observation angle corresponding to the third state in Figure 39. The observation angle θ1C may differ from the observation angle θ1 in Figure 37, but here we assume θ1C = θ1. Let the user's viewpoint position be viewpoint position 3501C. The viewpoint position 3501C may differ from the viewpoint position 3501 in Figure 37. The floating spatial image display device 1000 controls the display of the standing character image 3901 in accordance with this third state. As an example of this display control, the character image 3901 is displayed at a selected display depression angle D. Here, the display depression angle D is set to approximately 45 degrees. In this case, as shown in the figure, the basic posture angle of the character becomes close to the vertical direction 3702. Also, the positioning angle of the standing posture of the character image 3901 relative to the front side of the stage surface 500 is approximately 80 degrees, from 90 degrees + γ - R3, assuming an angle φ3.

[0382] The above embodiment 4 (Figures 37 to 39) is configured such that the angle of the pivoting angle by the angle adjustment mechanism 3700 is predetermined as several angles to choose from. For example, as shown in Figures 37 to 39, the user can manually select from three different angles (e.g., 0 degrees, +20 degrees, -20 degrees). The angle adjustment mechanism 3700 stably maintains the selected angle state by a mechanism such as a torque hinge on the shaft portion 3731. For example, a user in a vehicle uses the floating image display device 1000 housed and installed in a bottle holder. In this case, the observation angle depends on the positional relationship between the bottle holder and the user's viewpoint, and the required vertical viewing range may change. In this case, as a solution, embodiment 4 allows for adjustment of the position of the floating image 3 by rotating it forward and backward using the angle adjustment mechanism 3700.

[0383] By adjusting this panning angle, the upright image 3A can be positioned at a desired tilt angle (e.g., 65 degrees, 85 degrees, 45 degrees) to match the user's viewing angle and required field of view. The floating spatial image display device 1000 then changes the display orientation of the character image based on software processing (the aforementioned preset or rendering) to match the position of the upright image 3A with this hardware configuration. For example, the display depression angle D for each state is 25 degrees, 5 degrees, and 45 degrees, and the appearance to the user remains constant, like an upright position relative to the horizontal plane. As a result, regardless of the panning angle of the angle adjustment mechanism 3700, the display of the character image and the vertical field of view can be adjusted appropriately for each angle.

[0384] The angle adjustment mechanism 3700 allows for adjustment of swivel angles, and the options are not limited to the three types of angles described above. The angle adjustment mechanism 3700 is configured to allow stepwise changes to a predetermined set of angles. For example, if only the three types of angles described above are used for three stages, it is possible to transition between the first state in Figure 37 and the second state in Figure 38, and between the first state in Figure 37 and the third state in Figure 39. Furthermore, if two additional angles are added between the three types of angles to create five stages, it is possible to transition from the first state in Figure 37 to the fourth state, which is an angle intermediate between the first and second states, and to the fifth state, which is an angle intermediate between the first and third states.

[0385] Furthermore, depending on the implementation, the angle adjustment mechanism 3700 may be configured to continuously change the swivel angle within a predetermined upper and lower angle range. For example, it may be configured to allow arbitrary selection from a continuous range of values ​​within an angle range where the forward tilt angle in Figure 38 and the backward tilt angle in Figure 39 are the upper and lower limits. In this case as well, the angle adjustment mechanism 3700 should be a mechanism that can stably maintain the selected angle.

[0386] The above embodiment 4 shows a configuration that can be housed in a bottle holder, where the tilt angle γ of the optical plate 150 is based on 10 degrees. However, it is not limited to this, and a configuration based on the one shown in Figure 19, where the tilt of the optical plate 150 is 0 degrees and the horizontal plane is the basic configuration (first state), is also possible.

[0387] Furthermore, within the angle range adjustable by the angle adjustment mechanism 3700, one of the user-selectable angles may include the angle in which the optical plate 150 is in a horizontal plane state, as shown in Figure 41. In the modified example of Figure 41, when the angle adjusted by the angle adjustment mechanism 3700 is RX, the optical plate 150 is positioned along the horizontal axis H. Such angles may be added in addition to, or instead of, the three stages of panning angles shown in Figures 37 to 39. Also, in the example of Figure 41, when displaying the character image 4101 of the standing figure 3A in the RX state, the basic posture angle is set to the vertical direction 3702 by setting a predetermined display depression angle D. In this case, the character image 4101 appears to be standing on the stage surface 500, which is a horizontal plane.

[0388] As a variation, the angle adjustment mechanism 3700 may be equipped with a drive mechanism such as a motor. The control board 3710 may automatically control the drive mechanism to change the swivel angle of the angle adjustment mechanism 3700.

[0389] [Variable control of display angle (downward tilt) according to the swivel angle] As already shown above, the floating image display device 1000 of Embodiment 4 may variably control the display content of the character image according to the arrangement angle state of the upper housing 1190B and the floating image 3 by the angle adjustment mechanism 3700. The floating image display device 1000 controls the display to select and display the character image's downward angle D from a preset according to the state of the head-turning angle. When the arrangement angle is changed in response to manual operation of the angle adjustment mechanism 3700, the floating image display device 1000 changes the display downward angle of the character image to match the changed arrangement angle and displays it accordingly.

[0390] Variable control of the display depression angle of the character image according to the head-turning angle and the placement angle of the floating image 3 is possible in various ways. Several examples are given below. One example of control is to keep the display depression angle constant for each head-turning angle. Another example of control is to select and adjust each display depression angle so that the angle of the character's standing posture remains unchanged and constant in appearance for each head-turning angle.

[0391] [Control to keep the character's posture constant in the video] Figure 42 shows an example of controlling the display depression angle according to the swivel angle. Any of the control examples may be adopted. This example assumes that it is possible to select from the three types of swivel angles (Figures 37 to 39) described above. In Figure 42, the standing figure 3A and other elements from Figures 37 to 39 are extracted to illustrate a conceptual image.

[0392] Control Example 1, as shown in Figures 37 to 39, sets the display depression angle D to 25 degrees in the first state (R1=0 degrees, B=65 degrees), to 5 degrees in the second state (R2=+20 degrees, B=85 degrees), and to 45 degrees in the third state (R2=-20 degrees, B=45 degrees). In the second state, the display depression angle D of the standing posture is reduced because the screen of the standing figure 3A is tilted forward and closer to vertical, and in the third state, the display depression angle D of the standing posture is increased because the screen is tilted backward and further away from vertical. As a result, no matter which angle is changed by the angle adjustment mechanism 3700, when the user views the standing figure 3A at each tilt angle B, the standing posture of the character image within the standing figure 3A appears unchanged and constant as a 90-degree (vertical) posture with respect to the horizontal axis H.

[0393] Furthermore, as in Control Example 1, the angle of the standing posture that remains constant regardless of the head rotation angle (referred to as the constant posture angle; for example, 90 degrees to the horizontal, 0 degrees to the vertical) can be specified, selected, or set by the user as their preferred angle.

[0394] Control Example 2 shows a case where the constant attitude angle is set to, for example, 65 degrees horizontally and -25 degrees vertically, based on user specifications. To achieve this constant attitude angle, the display depression angle is controlled to be 0 degrees in the first state, -20 degrees in the second state, and +20 degrees in the third state.

[0395] Control Example 3 shows a case where the constant attitude angle is set to, for example, 115 degrees horizontally and +25 degrees vertically, based on user specifications. To achieve this constant attitude angle, the display depression angle is controlled to be 50 degrees in the first state, 30 degrees in the second state, and 70 degrees in the third state.

[0396] Figure 43 shows another control example. Control example 4 is a case where the display depression angle D within the standing image 3A is kept constant at 25 degrees regardless of the head-turning angle. In this case, as shown in the figure, in the first state the character is upright (90 degrees) relative to the horizontal axis H, in the second state the character is tilted forward relative to the horizontal axis H, and in the third state the character is tilted backward relative to the horizontal axis H. Depending on the user's viewpoint position and observation angle, the user environment and circumstances may not feel unnatural even in these postures, and therefore this control example can be adopted.

[0397] Furthermore, the display depression angle D, which is kept constant regardless of the swivel angle as in control example 4, can also be specified, selected, and set by the user as their preferred angle.

[0398] As shown in the example above, when the panning angle is changed by the angle adjustment mechanism 3700, the positions of the standing image 3A and the character image in three-dimensional space will change (see also Figure 45 below). Users can select and use the desired panning angle and character image orientation that best suits their preferred viewpoint position, observation angle, and other usage conditions.

[0399] The control examples 1 to 4 above show the control of the display depression angle D, but the same can be applied to the control of the face display elevation angle E as described above. In other words, the display elevation angle E of the face should be controlled in accordance with the head rotation angle.

[0400] Control Example 5 is a variation of Control Example 1, adding a control to the constant standing posture control that sets the face display elevation angle E to 45 degrees. Assuming a downward angle of 45 degrees as the user's observation angle, the face display elevation angle E is set to 45 degrees in all three states: the first, second, and third states.

[0401] Furthermore, control example 6 is an example in which the face display elevation angle E is changed according to the state of the head swing angle. In the first state, the face display elevation angle E is set to 45 degrees, in the second state, the face display elevation angle E is set to 65 degrees, and in the third state, the face display elevation angle E is set to 25 degrees.

[0402] When the user sets the above-mentioned constant posture angle or a fixed display depression angle, for example, the user can select, specify, and set the angle on a user setting screen similar to Figure 28. When specifying the constant posture angle, the user can directly select from values ​​such as 90 degrees, 95 degrees, and 85 degrees relative to the horizontal, or they can specify it in terms of the display depression angle in the first state (angle R1 = 0 degrees).

[0403] Similarly, even in a configuration without the angle adjustment mechanism 3700 as shown in Figure 35, it is possible for the user to set their preferred standing posture angle (corresponding display depression angle, etc.).

[0404] [Controlling the display position and size of character images] In Embodiment 4, when displaying the character image of the floating image 3, in addition to controlling the display depression angle D and display elevation angle E according to the head-turning angle as described above, the display position and size of the character image within the floating image 3 may also be variably controlled as follows. The floating image display device 1000 adjusts the position and size of the character image, in other words, the layout, within the screen of the standing image 3A, according to the display depression angle D of the character image's standing posture. This ensures a uniform viewing angle / viewing range in the vertical direction, prevents the screen from being cut off, and achieves a display that is easier to see.

[0405] Figure 44 shows an example of variable control of the display position and size of the character image within the floating spatial image 3 according to the head-turning angle. Figure 44 shows a 2D image corresponding to the display range 3R of the floating spatial image 3. Example 1 is an example of the character image when the user views the floating spatial image 3 from the front (viewed in the direction of the screen normal). In this example, character image 4401 is in a basic upright standing posture, and in terms of the shooting direction (downward angle) of the virtual camera described above (Figure 24), it is set to 0 degrees, and the image captures the front of the character's body. Point A is an example of the display position of character image 4401, and is an example based on the feet.

[0406] The character image 4402 in Example 2 is an example of an image generated based on the basic standing character image 4401 in Example 1, with the aforementioned virtual camera's downward angle set to 65 degrees and the display downward angle D set to 65 degrees, and corresponds to image 2504 in Figure 25. In Example 2, within the screen corresponding to the display range 3R, the image area of ​​the character image 4402 is positioned towards the bottom. Here, the character's display position is based on the feet, and an example of the display position is shown by point B, etc. The space at the bottom of the screen 4402a is relatively small, and the space at the top of the screen 4402b is relatively large and empty. If the display downward angle D, etc. is changed while maintaining the size and proportion of the character's body, the size of the character image area on the screen (for example, the vertical width) changes.

[0407] When displaying character video 4402 as in Example 2, that is, when the character image area is positioned towards the bottom of the screen, as shown in Figure 34 above, depending on the user's viewing angle, there is a risk that part of the character video may be invisible or difficult to see. In character video 4402 of Example 2, depending on the user's downward viewing angle, the bottom of the screen may be cut off, making it appear as if the character's feet are missing and therefore invisible. As a countermeasure, the display position of the character video on the screen may be adjusted.

[0408] The character video 4403 in Example 3 is an example of an image after adjusting the position of the image area of ​​the character video on the screen, based on the character video 4402 in Example 2. Specifically, by centering the image area of ​​the character video to be near the center of the screen, point C of the display position of the character video 4403 has moved higher than point B. The same is true when considering the display position of the character video at the center of the image area (for example, points Bb and Cc), where point Cc is positioned near the center of the screen, higher than point Bb. This creates a lower space 4403a and an upper space 4403b on the screen. The lower space 4403a is larger than the lower space 4402a in Example 2 and is about the same size as the upper space 4403b.

[0409] In Example 3, the lower space 4403a on the screen is larger, so even if the top or bottom of the image is cropped depending on the user's viewing angle, if that cropped area is contained within the lower space 4403a, for example, the loss of part of the character image is prevented or reduced. When using the image in Example 3, the upper and lower viewing angles can be ensured equally. If prioritizing countermeasures against cropping at the top of the screen, one may choose to display an image with a larger upper space 4402b, as in Example 2.

[0410] Furthermore, the character video 4404 in...

Claims

1. A floating image display device, A video processing unit that performs video processing, The aforementioned video processing unit displays the video that has been processed by the video processing unit, An optical system that generates an aerial levitation image based on the image displayed by the display unit, Equipped with, The optical system comprises a polarization separation member and a retroreflective member having a λ / 4 plate on its incident surface. The display unit comprises a display device that displays the image and a prism sheet arranged on the image light emitting surface of the display device. Image light having a first polarization from the display unit is incident on the polarization separation member at a first angle, reflected by the polarization separation member, the reflected image light is retroreflected by the retroreflector, converted to a second polarization by passing through the λ / 4 plate, the retroreflected image light having the second polarization passes through the polarization separation member and is emitted at the same angle as the first angle, forming the floating image in the air at a position that is mirror-symmetric with respect to the display device with respect to the polarization separation member. The aerial levitation image is positioned relative to the polarization separation member at a first inclination angle toward the user's viewpoint, and the display device is positioned relative to the polarization separation member on the opposite side from the aerial levitation image at the same inclination angle as the first inclination angle. The image light emitted perpendicular to the surface from the image light emitting surface of the display device is refracted by the prism sheet at a first refraction angle, and is incident on the polarization separation member at the first angle. Aerial levitation display device.

2. In the aerial floating image display device according to claim 1, The floating image formed by the image light retroreflected by the retroreflective member has a brightness peak when observed at the observation angle corresponding to the first angle. Aerial levitation display device.

3. In the aerial floating image display device according to claim 1, The aforementioned first angle is an angle within the range of 45 degrees ± 10 degrees. Aerial levitation display device.

4. In the aerial floating image display device according to claim 1, The first inclination angle is within the range of 65 degrees ± 10 degrees. Aerial levitation display device.

5. In the aerial floating image display device according to claim 1, The first angle of refraction is within the range of 20 degrees ± 10 degrees. Aerial levitation display device.

6. In the aerial floating image display device according to claim 1, The prism sheet is provided with an image light control sheet on its emission surface to reduce the amount of refracted light rays from the prism sheet that do not reach the polarization separation member and the retroreflective member, except for the light rays in the direction of the first refraction angle. Aerial levitation display device.

7. In the aerial floating image display device according to claim 6, The aforementioned video light control sheet has a structure in which light-shielding portions and light-transmitting portions are repeatedly arranged. The direction in which the light-shielding portion stands relative to the emission surface of the prism sheet is set to an oblique angle corresponding to the direction of the first refraction angle. Aerial levitation display device.

8. In the aerial floating image display device according to claim 6, The output surface of the image light control sheet is provided with a parallel polarizer for correcting polarization disturbances caused by the prism sheet or the image light control sheet for the image light having the first polarization emitted from the display device. Aerial levitation display device.

9. In the aerial floating image display device according to claim 1, The retroreflective member is positioned relative to the polarization separation member on the side opposite to the floating image in the air, at a predetermined inclination angle corresponding to the first angle. The predetermined inclination angle is within the range of 45 degrees ± 10 degrees. Aerial levitation display device.

10. In the aerial floating image display device according to claim 1, The housing of the aerial levitation image display device is provided with a retroreflective member angle adjustment mechanism for adjusting the rotation angle of the retroreflective member. Aerial levitation display device.

11. In the aerial floating image display device according to claim 10, The retroreflective member angle adjustment mechanism rotates the retroreflective member to a predetermined inclination angle within a range of 45 degrees ± 10 degrees. Aerial levitation display device.

Images