Aerial floating image display apparatus

Abstract

Provided is a more suitable aerial floating image display apparatus. The present invention contributes to the Sustainable Development Goals (SDGs) of "3. Good health and well-being", "9. Industry, innovation, and infrastructure", and "11. Sustainable cities and communities". This aerial floating image display apparatus comprises a display apparatus and an optical plate including a retroreflective member, and further comprises a prism sheet disposed on an image light emission surface of the display apparatus. The display apparatus is disposed on the lower side and at a first inclination angle with respect to the optical plate, and the aerial floating image is disposed on the upper side and at an inclination angle the same as the first inclination angle with respect to the optical plate. Image light emitted from the display apparatus is refracted by the prism sheet, and is thereby incident on the optical plate at a first angle. An aerial floating image is formed at a position which is mirror-symmetrical with respect to the display device, with the optical plate as a boundary.

Description

Floating image display device

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

[0002] The floating information display technology is disclosed in, for example, Patent Document 1.

[0003] Japanese Patent Application Laid-Open No. 2019-128722

[0004] However, the disclosure of Patent Document 1 does not sufficiently consider configurations for obtaining practical brightness and quality for the floating image, or configurations for allowing users to view the floating image more enjoyably.

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

[0006] In order to solve the above problem, for example, the configuration described in the claims is adopted. The present application includes a plurality of means for solving the above problem, and an example thereof may be configured as follows: A floating-in-the-air image display device, comprising: an image processing unit that performs image processing; a display unit that displays an image processed by the image processing unit; and an optical system that generates a floating-in-the-air image based on the image displayed by the display unit, wherein the optical system has an optical plate including a retroreflective member, and the display unit has a display device that displays an image and a prism sheet arranged on an image light exit surface of the display device, and the image light from the display unit is incident on a polarization separation member at a first angle and reflected by the polarization separation member, and the reflected image light is reflected by the optical plate at a first angle. The image light is incident at an angle and retroreflected by the retroreflective member, and is emitted at the same angle as the first angle, forming a floating image at a position that is mirror-symmetrical to the display device with the optical plate as the boundary, the display device is positioned below the optical plate at the first tilt angle, and the floating image is positioned above the optical plate at the same tilt angle as the first tilt angle, and the image light emitted from the image light emission surface of the display device in a direction perpendicular to the surface is refracted by the prism sheet at the first refraction angle, and is incident on the optical plate at the first angle.

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

[0008] FIG. 1 is a diagram showing an example of a usage form of a space-floating image display device according to an embodiment of the present invention. FIG. 2 is a diagram showing an example of a configuration of a main part and a retroreflector of a space-floating image display device according to an embodiment of the present invention. FIG. 3 is a diagram showing an example of a configuration of a main part and a retroreflector of a space-floating image display device according to an embodiment of the present invention. FIG. 4 is a diagram showing an example of a configuration of a main part and a retroreflector of a space-floating image display device according to an embodiment of the present invention. FIG. 5 is a diagram showing an example of a configuration of a main part and a retroreflector of a space-floating image display device according to an embodiment of the present invention. FIG. 6 is a projection diagram of a retroreflector constituting a space-floating image display device according to an embodiment of the present invention. FIG. 7 is a top view of a retroreflector constituting a space-floating image display device according to an embodiment of the present invention. FIG. 8 is a perspective view of a corner reflector constituting a retroreflector constituting a space-floating image display device according to an embodiment of the present invention. FIG. 9 is a top view of a corner reflector constituting a retroreflector constituting a space-floating image display device according to an embodiment of the present invention. FIG. 10 is a side view of a corner reflector constituting a retroreflector constituting a space-floating image display device according to an embodiment of the present invention. FIG. 11 is a diagram showing an example of a configuration of a space-floating image display device according to an embodiment of the present invention. FIG. 1 is a diagram showing an example of the configuration of a space-floating image display device according to an embodiment of the present invention. FIG. 2 is a diagram showing an example of the configuration of a space-floating image display device according to an embodiment of the present invention. FIG. 3 is a diagram showing an example of the configuration of a space-floating image display device according to an embodiment of the present invention. FIG. 4 is a diagram showing an example of the configuration of a space-floating image display device according to an embodiment of the present invention. FIG. 5 is a diagram showing an example of the configuration of a space-floating image display device according to an embodiment of the present invention. FIG. 6 is a diagram showing an example of the configuration of a space-floating image display device according to an embodiment of the present invention. FIG. 7 is a diagram showing an example of the configuration of a space-floating image display device according to an embodiment of the present invention. FIG. 8 is a diagram showing an example of the configuration of a space-floating image display device according to an embodiment of the present invention.FIG. 1 is a diagram showing an example of the configuration of a space-floating image display device according to an embodiment of the present invention. FIG. 2 is a diagram showing an example of the configuration of a space-floating image display device according to an embodiment of the present invention. FIG. 3 is a cross-sectional view showing an example of a specific configuration of a light source device according to an embodiment of the present invention. FIG. 4 is a cross-sectional view showing an example of a specific configuration of a light source device according to an embodiment of the present invention. FIG. 5 is a cross-sectional view showing an example of a specific configuration of a light source device according to an embodiment of the present invention. FIG. 6 is a layout diagram showing main parts of a space-floating image display device according to an embodiment of the present invention. FIG. 7 is a cross-sectional view showing the configuration of a display device according to an embodiment of the present invention. FIG. 8 is a cross-sectional view showing the configuration of a display device according to an embodiment of the present invention. FIG. 9 is an explanatory diagram for explaining light source diffusion characteristics of an image display device according to an embodiment of the present invention. FIG. 10 is an explanatory diagram for explaining diffusion characteristics of an image display device according to an embodiment of the present invention. FIG. 11 is an explanatory diagram for explaining an example of a problem solved by image processing according to an embodiment of the present invention. FIG. 12 is an explanatory diagram for explaining an example of image processing according to an embodiment of the present invention. FIG. 13 is an explanatory diagram for explaining an example of image display processing according to an embodiment of the present invention. FIG. 14 is a diagram showing an example of the configuration of a main part and a retroreflection part of a space-floating image display device according to an embodiment of the present invention. FIG. 15 is a diagram showing an example of the configuration of an optical system of a space-floating image display device as a comparative example according to an embodiment. FIG. 16 is a diagram showing an example of the configuration of an optical system of a space-floating image display device as a comparative example according to an embodiment. 1 is a diagram showing an example of the configuration of a prism sheet according to an embodiment; FIG. 2 is a diagram showing an example of the configuration of a space-floating image display device according to an embodiment; FIG. 3 is a diagram showing an example of the configuration of a housing of a space-floating image display device according to an embodiment; FIG. 4 is a diagram showing an example of the configuration of a control unit etc. of a space-floating image display device according to an embodiment; FIG. 5 is a diagram showing an example of the configuration of a space-floating image of a space-floating image display device of a comparative example according to an embodiment; FIG. 6 is a diagram showing an example of the configuration of a space-floating image of a space-floating image display device according to an embodiment; FIG. 7 is a diagram showing an example of the setting of a virtual camera in a virtual 3D space according to an embodiment; FIG. 8 is a diagram showing an example of an image with a changed display depression angle according to an embodiment; FIG. 9 is an explanatory diagram regarding the display depression angle according to an embodiment; FIG. 10 is a diagram showing an example of switching images using a switch button according to an embodiment; FIG. 11 is a diagram showing an example of a user setting screen according to an embodiment; FIG. 12 is a diagram showing an external device and a space-floating image display device according to an embodiment;1 is a diagram showing an example of a display such as an idling state according to one embodiment; FIG. 2 is an explanatory diagram related to the display elevation angle of a face according to one embodiment; FIG. 3 is a diagram showing an example of an image when the display elevation angle of the face is changed according to one embodiment; FIG. 4 is a diagram showing an example of how a space-floating image appears according to one embodiment; FIG. 5 is a diagram showing an example of a configuration of a space-floating image display device of a comparative example according to one embodiment; FIG. 6 is a diagram showing an example of a configuration of an optical system of a space-floating image display device according to one embodiment; FIG. 7 is a diagram showing an example of a configuration of an optical system of a space-floating image display device of a modified example according to one embodiment; FIG. 8 is a diagram showing a first state of an angle adjustment mechanism in a space-floating image display device according to one embodiment; FIG. 9 is a diagram showing a second state of an angle adjustment mechanism in a space-floating image display device according to one embodiment; FIG. 10 is a diagram showing a third state of an angle adjustment mechanism in a space-floating image display device according to one embodiment; FIG. 11 is a diagram showing an example of installation to a bottle holder according to one embodiment; FIG. 12 is a diagram showing one state of the angle adjustment mechanism in a space-floating image display device according to one embodiment; FIG. 13 is a diagram showing an example of display control according to the state of the angle adjustment mechanism according to one embodiment; FIG. 14 is a diagram showing an example of display control according to the state of the angle adjustment mechanism according to one embodiment; FIG. 15 is a diagram showing an example of an image whose display position and size have been adjusted according to one embodiment; FIG. 16 is a diagram showing an example of display control according to the state of the angle adjustment mechanism according to one embodiment; 1 is a diagram showing an example of the configuration of a lower housing according to an embodiment; FIG. 2 is a diagram showing an example of the configuration of a lower housing according to an embodiment; FIG. 3 is a diagram showing the relationship between the number of swing angle selections and the number of constant attitude angle selections according to an embodiment; FIG. 4 is a diagram showing an example of the configuration of an optical system of a space-floating image display device of a comparative example (first comparative example) according to an embodiment; FIG. 5 is a diagram showing an example of the configuration of an optical system of a space-floating image display device of a comparative example (second comparative example) according to an embodiment; FIG. 6 is a diagram showing an example of the configuration of an optical system of a space-floating image display device (when the angle of the retroreflector is 45 degrees) according to an embodiment; FIG. 7 is a diagram showing an example of the configuration of an optical system of a space-floating image display device (when the angle of the retroreflector is 35 degrees) according to an embodiment; FIG. 8 is a diagram showing an example of the configuration of an optical system of a space-floating image display device (when the angle of the retroreflector is 55 degrees) according to an embodiment; FIG. 9 is a diagram showing an example of the configuration of a cross section of a display device according to an embodiment; FIG. 10 is a diagram showing an example of the configuration of a cross section of a display device (modified VCF) according to an embodiment.1 is a diagram showing a configuration example of a space-floating image display device according to an embodiment (when the angle of the retroreflector is 45 degrees); 2 is a diagram showing a configuration example of a space-floating image display device according to an embodiment (when the angle of the retroreflector is 35 degrees); 3 is a diagram showing a configuration example of a space-floating image display device according to an embodiment (when the angle of the retroreflector is 55 degrees).

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the description of the embodiments, and various changes and modifications can be made by those skilled in the art within the scope of the technical ideas disclosed in this specification. Furthermore, in all drawings used to explain the present invention, components having the same functions are given the same reference numerals, and repeated explanations thereof may be omitted.

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

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

[0012] First Embodiment An example of the configuration of a space floating image display device will be described below as a first embodiment of the present invention.

[0013] <Example of Usage of the Space-Floating Image Display Device> Figure 1 is a diagram showing an example of usage of a space-floating image display device according to an embodiment of the present invention, and is a diagram showing the overall configuration of the space-floating image display device according to this embodiment. The specific configuration of the space-floating image display device will be described in detail using Figure 2 and other figures. Light with a narrow-angle directional characteristic and specific polarization is emitted from the image display device 1 as an image light beam, reflected by the optical system within the space-floating image display device, and then incident on the retroreflector 2, retroreflected and transmitted through a transparent member 100 (glass, etc.), forming a real aerial image (space-floating image 3) on the outside of the glass surface. In the following examples, the retroreflector 2 (retroreflector) will be used as an example of the retroreflector. However, the retroreflector 2 of the present invention is not limited to a planar plate, and is used as an example of a concept including a sheet-like retroreflector attached to a planar or non-planar member, or an entire assembly in which a sheet-like retroreflector is attached to a planar or non-planar member. Furthermore, since the light rays reflected by the retroreflector 2 have the optical property of forming an image, the retroreflector 2 may also be expressed as an imaging optical member or an imaging optical plate.

[0014] In addition, in a store or the like, a space is partitioned by a show window (also called "window glass") 105, which is a transparent member such as glass. According to the space floating image display device of this embodiment, it is possible to transmit such a transparent member and display a floating image in one direction to the outside and / or inside of the store (space).

[0015] 1, the inside of the window glass 105 (inside the store) is shown in the depth direction, and the outside (for example, the sidewalk) is shown in the foreground. On the other hand, by providing a means for reflecting specific polarized waves in the window glass 105, it is possible to form an aerial image at a desired position inside the store by reflecting the specific polarized waves.

[0016] <Configuration Example of Optical System of Space-Floating Image Display Device> Figure 2A is a diagram showing an example of the configuration of an optical system of a space-floating image display device according to one embodiment of the present invention. The configuration of the space-floating image display device will be described in more detail using Figure 2A. As shown in Figure 2A (1), a display device 1 that diverges specific polarized image light at a narrow angle is provided in an oblique direction of a transparent member 100 such as glass. The display device 1 includes a liquid crystal display panel 11 and a light source device 13 that generates specific polarized light with narrow-angle diffusion characteristics.

[0017] 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) provided on a transparent member 100 and has a film that selectively reflects image light of a specific polarization, and then enters the retroreflector 2. A λ / 4 plate 21 is provided on the image light incident surface of the retroreflector 2. The image light is polarized and converted from the specific polarization to the other polarization by passing through the λ / 4 plate 21 twice, once when entering the retroreflector 2 and once when exiting. Here, the polarization separation member 101, which selectively reflects image light of a specific polarization, has the property of transmitting the polarized light of the other polarization that has been polarization-converted, so the image light of the specific polarization after polarization conversion passes through the polarization separation member 101. The image light that has passed through the polarization separation member 101 forms a spatially floating image 3, which is a real image, outside the transparent member 100. 2A shows an example in which the chief ray of the image light incident on the retroreflector 2 is incident at an angle of 90° to the retroreflector 2. However, the incident angle of the chief ray of the image light on the retroreflector 2 is not limited to 90°, and an angle of, for example, 90°±15° can also be used.

[0018] Here, a first example of polarization design for the optical system of FIG. 2A will be described. For example, a configuration may be adopted in which S-polarized (S stands for Senkrecht; polarized light whose electric field oscillates perpendicular to the plane of incidence) image light is emitted from the display device 1 to the polarization separation member 101, and the polarization separation member 101 has the property of reflecting S-polarized light and transmitting P-polarized (P stands for parallel; polarized light whose electric field oscillates within the plane of incidence) 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 proceeds toward the retroreflector 2. When the image light is reflected by the retroreflector 2, it passes twice through the λ / 4 plate 21 provided on the incident surface of the retroreflector 2, and the image light is converted from S-polarized to P-polarized light. The P-polarized image light then proceeds toward the polarization separation member 101 again. Here, the polarization separation member 101 has the property of reflecting S-polarized light and transmitting P-polarized light, so the P-polarized image light passes through the polarization separation member 101 and then through the transparent member 100. The image light that passes through the transparent member 100 is light generated by the retroreflector 2, and therefore forms a space-floating image 3, which is an optical image of the image displayed on the display device 1, at a position that is in a mirror relationship with the image displayed on the display device 1 relative to the polarization separation member 101. This polarization design makes it possible to appropriately form the space-floating image 3.

[0019] Next, a second example of polarization design for the optical system of FIG. 2A will be described. For example, a configuration may be adopted in which P-polarized image light is emitted from the display device 1 to the polarization separation member 101, and the polarization separation member 101 has the property of reflecting P-polarized light and transmitting 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 proceeds toward the retroreflector 2. When the image light is reflected by the retroreflector 2, it passes twice through the λ / 4 plate 21 provided on the incident surface of the retroreflector 2, thereby converting the image light from P-polarized light to S-polarized light. The image light converted to S-polarized light proceeds again toward the polarization separation member 101. Here, the polarization separation member 101 has the property of reflecting P-polarized light and transmitting S-polarized light, so the S-polarized image light passes through the polarization separation member 101 and then through the transparent member 100. The image light transmitted through the transparent member 100 is light generated by the retroreflector 2, and therefore forms a floating image 3, which is an optical image of the image displayed on the display device 1, at a position that is in a mirror relationship with the image displayed on the display device 1 relative to the polarization separation member 101. This polarization design allows the floating image 3 to be formed optimally.

[0020] The light forming the space-floating image 3 is a collection of light rays that converge from the retroreflector 2 to the optical image of the space-floating image 3, and these light rays continue to travel in a straight line even after passing through the optical image of the space-floating image 3. Therefore, the space-floating image 3 is an image with high directionality, unlike the diffuse image light formed on a screen by a general projector or the like. Therefore, in the configuration of FIG. 2A, when a user views the space-floating image 3 from the direction of arrow A, the space-floating image 3 is perceived as a bright image. However, when another person views the space-floating image 3 from the direction of arrow B, the space-floating image 3 cannot be seen as an image at all. This characteristic is very suitable for use in systems that display images that require high security or highly confidential images that should be kept secret from people directly facing the user.

[0021] Depending on the performance of the retroreflector 2, the polarization axis of the reflected image light may become irregular. The reflection angle may also become irregular. Such irregular light may not maintain the polarization state and propagation angle assumed in the design. For example, light with an unintended polarization state and propagation angle may re-enter the image display surface of the liquid crystal display panel 11 directly from the position of the retroreflector 2 without passing through the polarization separation member. Such light with an unintended polarization state and propagation angle may be reflected by components within the space-floating image display device and then re-enter the image display surface of the liquid crystal display panel 11. Such light re-entering the image display surface of the liquid crystal display panel 11 may be re-reflected by the image display surface of the liquid crystal display panel 11 constituting the display device 1, potentially generating ghost images and degrading the image quality of the space-floating image. Therefore, in this embodiment, an absorbing polarizer 12 may be provided on the image display surface of the display device 1. The image light emitted from the display device 1 is transmitted through the absorbing polarizer 12, and the reflected light returning from the polarization separation member 101 is absorbed by the absorbing polarizer 12, thereby suppressing the re-reflection. This makes it possible to prevent degradation of image quality due to ghost images of spatially floating images. Specifically, if the display device 1 is configured to emit S-polarized image light to the polarization separation member 101, the absorbing polarizer 12 may be a polarizer that absorbs P-polarized light. Furthermore, if the display device 1 is configured to emit P-polarized image light to the polarization separation member 101, the absorbing polarizer 12 may be a polarizer that absorbs S-polarized light.

[0022] The polarization separation member 101 may be formed of, for example, a reflective polarizing plate or a metal multilayer film that reflects specific polarized waves.

[0023] 2A(2) shows an example of the surface shape of a typical retroreflector 2. A prism body with a regularly arranged array of triangular pyramidal recessed reflective surfaces is arranged on the retroreflector 2. Light rays incident on the array of triangular pyramidal recessed surfaces are reflected by the multiple reflective surfaces of the triangular pyramidal recessed surfaces and are emitted as retroreflected light in a direction corresponding to the incident light, thereby displaying a real image floating in space based on the image displayed on the display device 1.

[0024] The surface shape of the retroreflector according to this embodiment is not limited to the above example. Various surface shapes that achieve retroreflection may be used. Specifically, the surface of the retroreflector according to this embodiment may be provided with retroreflection elements in which triangular pyramidal prisms, hexagonal pyramidal prisms, other polygonal prisms, multi-vertex prisms, or combinations thereof are periodically arranged. Alternatively, the surface of the retroreflector according to this embodiment may be provided with retroreflection elements in which these prisms are periodically arranged to form cube corners. These may also be referred to as corner reflector arrays or polyhedral reflector arrays. Alternatively, the surface of the retroreflector according to this embodiment may be provided with capsule lens-type retroreflection elements in which glass beads are periodically arranged. The detailed configuration of these retroreflection elements can be achieved using existing technology, so a detailed description will be omitted. Specifically, the techniques disclosed in Japanese Patent Laid-Open Nos. 2001-33609, 2001-264525, 2005-181555, 2008-70898, and 2009-229942 may be used.

[0025] <Another configuration example 1 of the optical system of the space-floating image display device> Another configuration example of the optical system of the space-floating image display device will be described using Fig. 2B. In Fig. 2B, components with the same reference numerals as Fig. 2A have the same functions and configurations as Fig. 2A. For such components, repeated explanations will be omitted to simplify the explanation.

[0026] In the optical system of FIG. 2B , similar to FIG. 2A , image light of a specific polarization is output from the display device 1. The image light of a specific polarization output from the display device 1 is input to a polarization separation member 101B. The polarization separation member 101B is a member that selectively transmits image light of a specific polarization. Unlike the polarization separation member 101 of FIG. 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 referred to as a polarization separation plate. The polarization separation member 101B may be configured as a reflective polarizing plate configured by attaching a polarization separation sheet to a transparent member. Alternatively, the transparent member may be formed of a metal multilayer film that selectively transmits specific polarization and reflects polarization of other specific polarizations. In FIG. 2B , the polarization separation member 101B is configured to transmit image light of 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 and converted from a specific polarization to the other polarization by passing through the λ / 4 plate 21 twice, once when it enters the retroreflector and once when it leaves. Here, the polarization separation member 101B has the property of reflecting the polarized light of the other polarization that has been polarized and converted by the λ / 4 plate 21, so the image light after polarization conversion is reflected by the polarization separation member 101B. The image light reflected by the polarization separation member 101B passes through the transparent member 100 and forms a space-floating image 3, which is a real image, outside the transparent member 100.

[0028] Here, a first example of polarization design for the optical system of FIG. 2B will be described. For example, a configuration may be adopted in which P-polarized image light is emitted from the display device 1 to the polarization separation member 101B, and the polarization separation member 101B has the property of reflecting S-polarized light and transmitting P-polarized light. In this case, the P-polarized image light that reaches the polarization separation member 101B from the display device 1 passes through the polarization separation member 101B and proceeds to the retroreflector 2. When the image light is reflected by the retroreflector 2, it passes twice through the λ / 4 plate 21 provided on the incident surface of the retroreflector 2, and the image light is converted from P-polarized light to S-polarized light. The image light converted to S-polarized light proceeds again to the polarization separation member 101B. Here, the polarization separation member 101B has the property of reflecting S-polarized light and transmitting P-polarized light, so the S-polarized image light is reflected by the polarization separation member 101 and passes through the transparent member 100. The image light transmitted through the transparent member 100 is light generated by the retroreflector 2, and therefore forms a floating image 3, which is an optical image of the image displayed on the display device 1, at a position that is in a mirror relationship with the image displayed on the display device 1 relative to the polarization separation member 101B. This polarization design allows the floating image 3 to be formed optimally.

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

[0030] In FIG. 2B , the image display surface of the display device 1 and the surface of the retroreflector 2 are arranged parallel to each other. The polarization separation member 101B is arranged at an angle α (e.g., 30°) with respect to the image display surface of the display device 1 and the surface of the retroreflector 2. Then, upon reflection by the polarization separation member 101B, the direction of travel of the image light reflected by the polarization separation member 101B (the direction of the chief ray of the image light) differs by an angle β (e.g., 60°) from the direction of travel of the image light incident from the retroreflector 2 (the direction of the chief ray of the image light). With this configuration, in the optical system of FIG. 2B , the image light is output at a predetermined angle shown toward the outside of the transparent member 100, forming a real image, the floating-in-space image 3. In the configuration of FIG. 2B , when viewed by a user from the direction of arrow A, the floating-in-space image 3 is perceived as a bright image. However, when viewed by another person from the direction of arrow B, the floating-in-space image 3 cannot be perceived as an image at all. This characteristic is extremely suitable for use in a system that displays images that require high security or highly confidential images that should be concealed from people directly facing the user.

[0031] As described above, the optical system of FIG. 2B has a different configuration from the optical system of FIG. 2A, but can form a suitable floating image in space, similar to the optical system of FIG. 2A.

[0032] An absorptive polarizing plate may be provided on the surface of the transparent member 100 facing the polarization separation member 101B. This absorptive polarizing plate may transmit the polarized light of the image light from the polarization separation member 101B and absorb the polarized light that is 90° out of phase with the polarized light of the image light from the polarization separation member 101B. In this way, the image light for forming the space-floating image 3 can be sufficiently transmitted while reducing the external light incident on the space-floating image 3 side of the transparent member 100 by approximately 50%. This makes it possible to reduce stray light in the optical system of FIG. 2B due to the external light incident on the space-floating image 3 side of the transparent member 100.

[0033] <Another configuration example 2 of the optical system of the space-floating image display device> Another configuration example of the optical system of the space-floating image display device will be described using Fig. 2C. Note that in Fig. 2C, components with the same reference numerals as Fig. 2B have the same functions and configurations as Fig. 2B. For the sake of simplicity, such components will not be described repeatedly.

[0034] The only difference between the optical system of Fig. 2B and the optical system of Fig. 2C is the arrangement 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 of Fig. 2B, so repeated explanations will be omitted. The polarization design of the optical system of Fig. 2C is also the same as that of the optical system of Fig. 2B, so repeated explanations will be omitted.

[0035] In the optical system of FIG. 2C , the polarization separation member 101B is tilted at an angle α with respect to the image display surface of the display device 1 and the surface of the retroreflector 2. In FIG. 2C , the angle α is 45°. With this configuration, when the polarization separation member 101B reflects, the angle β between the direction of propagation of the image light incident from the retroreflector 2 (the direction of the chief ray of the image light) and the direction of propagation of the image light reflected by the polarization separation member 101B (the direction of the chief ray of the image light) is 90°. With this configuration, the image display surface of the display device 1 and the surface of the retroreflector 2 are perpendicular to the direction of propagation of the image light reflected by the polarization separation member 101B, thereby simplifying the angular relationship between the surfaces that make up 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 relationship between the surfaces that make up the optical system can be further simplified. In the configuration of Figure 2C, when a user views the floating image 3 from the direction of arrow A, the floating image 3 is perceived as a bright image. However, when another person views the floating image 3 from the direction of arrow B, the floating image 3 cannot be seen as an image at all. This characteristic is very suitable for use in a system that displays images that require high security or highly confidential images that should be kept secret from people directly facing the user.

[0036] As described above, the optical system of Fig. 2C has a different configuration from the optical systems of Fig. 2A and Fig. 2B, but can form a suitable floating image in space similar to the optical systems of Fig. 2A and Fig. 2B. In addition, the angles of the surfaces constituting the optical system can be made simpler.

[0037] An absorptive polarizing plate may be provided on the surface of the transparent member 100 facing the polarization separation member 101B. This absorptive polarizing plate may transmit the polarized light of the image light from the polarization separation member 101B and absorb the polarized light that is 90° out of phase with the polarized light of the image light from the polarization separation member 101B. In this way, the image light for forming the space-floating image 3 can be sufficiently transmitted while reducing the external light incident on the space-floating image 3 side of the transparent member 100 by approximately 50%. This makes it possible to reduce stray light in the optical system of FIG. 2C due to the external light incident on the space-floating image 3 side of the transparent member 100.

[0038] <Another Configuration Example 3 of the Optical System of the Space-Floating Image Display Device> Another configuration example of the optical system of the space-floating image display device will be described using FIG. 2D. The optical system of FIG. 2D is an optical system that uses a retroreflector 5 that is different from the retroreflector 2 used in FIGS. 2A to 2C. Hereinafter, Another Configuration Example 3 of the optical system will be described in more detail using FIGS. 2D to 2I. In FIG. 2D, components that are assigned the same reference numerals as those in FIGS. 2A to 2C have the same functions and configurations as those in FIGS. 2A to 2C. Such components will not be described repeatedly in order to simplify the explanation.

[0039] 2D is a diagram showing an example of the main components and retroreflection components of a space-floating image display device according to an embodiment of the present invention. A display device 1 that emits image light is provided obliquely on a transparent member 100 such as glass. The display device 1 includes a liquid crystal display panel 11 and a light source device 13 that generates light.

[0040] A chief ray 9020 representing 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 may be, for example, 45°. However, the incident angle α is not limited to 45°, and may also be, for example, 45°±15°.

[0041] The retroreflector 5 is an optical element having the optical property of retroreflecting light rays in at least some directions. Furthermore, since the reflected light rays have the optical property of forming an image, the retroreflector 5 may also be referred to as an imaging optical element or an imaging optical plate.

[0042] 2E, 2F, etc., the principal ray 9020 travels in the z direction and is retroreflected in the x and y directions by the retroreflector 5. As a result, the reflected light ray 9021 travels in a direction away from the retroreflector 5 along an optical path that is mirror-symmetrical with respect to the principal ray 9020 with the retroreflector 5 as the reference, passes through the transparent member 100, and forms the floating image 3 in space as a real image on the imaging plane.

[0043] The light beam forming the space-floating image 3 is a collection of light rays that converge from the retroreflector 5 to the optical image of the space-floating image 3, and these light rays continue to travel in a straight line even after passing through the optical image of the space-floating image 3. Therefore, the space-floating image 3 is an image with high directionality, unlike a diffuse image formed on a screen by a general projector or the like. Therefore, in the configuration of FIG. 2, when a user views the space-floating image 3 from the direction of arrow A, the space-floating image 3 is perceived as a bright image. However, when another person views the space-floating image 3 from the direction of arrow B, the space-floating image 3 cannot be perceived as an image at all. This characteristic is suitable for use in a system that displays images that require high security or highly confidential images that should be kept secret from people directly facing the user.

[0044] An example of the configuration of the retroreflector 5 will be described 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 member. This may also be called a corner reflector array or a polyhedral reflector array. The specific configuration of the corner reflector 9040 will be described in detail using Figures 2G, 2H, and 2I. Light rays 9111, 9112, 9113, and 9114 emitted from a light source 9110 are reflected twice by two mirror surfaces 9041 and 9042 of the corner reflector 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 (traveling in a direction rotated 180 degrees), and in the z direction, where the angle of incidence and the angle of reflection match due to total reflection.

[0045] That is, the light rays 9111 to 9114 generate reflected light rays 9121 to 9124 on straight lines symmetrical in the z direction with respect to the corner reflector 9040, forming an aerial real image 9120. Note that the light rays 9111 to 9114 emitted from the light source 9110 are four light rays representing the diffused light from the light source 9110, and although the light rays incident on the retroreflector 5 are not limited to these, depending on the diffusion characteristics of the light source 9110, all incident light rays cause similar reflections and form an aerial real image 9120. Note that to make the drawing easier to see, the position of the light source 9110 and the position of the aerial real image 9120 are shown shifted in the x direction, but in reality, the position of the light source 9110 and the position of the aerial real image 9120 in the x direction are the same, and are overlapping when viewed from the z direction.

[0046] 2G, 2H, and 2I, the configuration and effects of the corner reflector 9040 that constitutes the retroreflector 5 will be described. The corner reflector 9040 is a rectangular parallelepiped with only two specific surfaces being mirror surfaces 9041 and 9042, and the other four surfaces being made of transparent materials. The retroreflector 5 has a configuration in which these corner reflectors 9040 are arrayed so that the corresponding mirror surfaces face in the same direction.

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

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

[0049] As described above, the light rays incident on the corner reflector 9040 undergo retroreflection, which results in an inverted optical path in the x and y directions, and specular reflection due to total reflection in the z direction. Considering the retroreflector 5, similar reflection occurs in each optical path, so that an image is formed at a point symmetrical with respect to the z axis direction by an inverted optical path that is convergent in the x and y directions.

[0050] 2A to 2C, the retroreflector 2 has retroreflection 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 retroreflector 2 where the light source of the incident light is located. The convergent reflected light beam forms an image in the air, forming a floating image 3. The traveling direction of the chief ray of the convergent reflected light beam reflected from the retroreflector 2 is opposite to the traveling direction of the chief ray of the diffusive incident light beam that is incident on the retroreflector 2.

[0051] 2D, the retroreflector 5 has retroreflection properties in two axial directions and specular reflection in the other axial direction. As a result, when a diffusive incident light beam is incident on the retroreflector 5, the convergent reflected light beam is reflected by the corner reflector array and travels in the direction opposite to the side of the retroreflector 5 where the light source of the incident light is located. The convergent reflected light beam forms an image in the air and forms the space floating image 3.

[0052] The traveling direction of the chief ray of the convergent reflected light beam reflected by the corner reflector array of the retroreflector 5 is not the opposite direction to the traveling direction of the chief ray of the diffusive incident light beam that is incident on the retroreflector 5. The normal direction component of the plate-shaped surface of the retroreflector 5 in the traveling direction of the chief ray of the diffusive incident light beam that is incident on the retroreflector 5 and the normal direction component of the plate-shaped surface of the retroreflector 5 in the traveling direction of the chief ray after being reflected by the retroreflector 5 and becoming a convergent reflected light beam, travel in a straight line, unchanged before and after reflection by the corner reflector array.

[0053] That is, the diffusive incident light beam is converted into a convergent reflected light beam by reflection on the retroreflector 5, but in the normal direction to the plate-shaped surface of the retroreflector 5, the light beam travels as if passing through the retroreflector 5. Here, the diffusive incident light beam incident on the retroreflector 5 and the convergent reflected light beam emerging from the retroreflector 5 are in a geometrically symmetrical relationship with respect to the plate-shaped surface of the retroreflector 5.

[0054] The resolution of the space-floating image formed by the light beams from the display device 1 depends not only on the resolution of the liquid crystal display panel 11, but also on the diameter D and pitch P (not shown) of the retroreflective portion of the retroreflector 5 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, one pixel of the space-floating image will be equivalent to 300 μm. As a result, the effective resolution of the space-floating image will be reduced to about one-third.

[0055] Therefore, in order to make the resolution of the spatial floating image equivalent to that of the display device 1, it is desirable to make the diameter D and pitch P of the retroreflective portion close to one pixel of the liquid crystal display panel. On the other hand, in order to suppress the occurrence of moire due to the retroreflective plate and the pixels of the liquid crystal display panel, it is advisable to design the pitch ratio of each to be a different integer multiple of one pixel. Furthermore, it is advisable to arrange the shape so that none of the sides of the retroreflective portion overlaps any of the sides of one pixel of the liquid crystal display panel.

[0056] The shape of the retroreflector (imaging optical plate) according to this embodiment is not limited to the above example. It may have various shapes that achieve retroreflection. Specifically, it may be a variety of cubic corner bodies, corner reflector arrays, slit mirror arrays, dihedral corner reflector arrays, polyhedral reflector arrays, or shapes in which a combination of these reflective surfaces is periodically arranged. Alternatively, capsule lens-type retroreflecting elements in which glass beads are periodically arranged may be provided on the surface of the retroreflector according to this embodiment. Since existing technology can be used for the detailed configuration of these retroreflecting elements, a detailed description will be omitted. Specifically, the technology disclosed in JP 2017-33005 A, JP 2019-133110 A, JP 2017-67933 A, WO 2009 / 131128 A, etc. may be used.

[0057] 2D, the image light emitted from the display device 1 may be in any polarization state, either S-polarized or P-polarized.

[0058] As described above, the optical system of FIG. 2D is an optical system that uses a retroreflector different from the optical systems of FIGS. 2A to 2C, but it can form a more suitable floating image in space, similar to the optical systems of FIGS. 2A to 2C.

[0059] According to the optical systems of FIGS. 2A, 2B, 2C, and 2D described above, it is possible to provide brighter and higher quality floating images in space.

[0060] <<Block Diagram of Internal Configuration of Space-Floating Image Display Device>> Next, a block diagram of the internal configuration of the space-floating image display device 1000 will be described. Fig. 3 is a block diagram showing an example of the internal configuration of the space-floating image display device 1000.

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

[0062] Each component of the space floating image display device 1000 is disposed in a housing 1190. Note that the imaging unit 1180 and the mid-air operation detection sensor 1351 shown in FIG.

[0063] The retroreflector 1101 in Figure 3 corresponds to the retroreflector 2 in Figures 2A, 2B, and 2C. The retroreflector 1101 retroreflects light modulated by the image display unit 1102. Of the light reflected from the retroreflector 1101, the light output to the outside of the space-floating image display device 1000 forms the space-floating image 3. When the optical system in Figure 2D is applied, the retroreflector 1101 corresponds to the retroreflector 5 in Figure 2D.

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

[0065] The video display unit 1102 is a display unit that generates a video by modulating transmitted light based on a video signal input under the control of a video control unit 1160 (described later). The video display unit 1102 (the aforementioned liquid crystal display panel 11) may be, for example, a transmissive liquid crystal panel, but is not limited to this. Alternatively, the video display unit 1102 may be, for example, a reflective liquid crystal panel that modulates reflected light, a DMD (Digital Micromirror Device: registered trademark) panel, or the like.

[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 source (LED: Light Emitting Diode) or a laser light source. The power supply 1106 converts AC current input from the outside via the external power supply 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 component within the space-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 requiring power via the external power supply input interface 1111 when power is not supplied from the outside. In other words, when the space-floating image display device 1000 is equipped with the secondary battery 1112, the user can use the space-floating image display device 1000 even when power is not supplied from the outside.

[0067] The light guide 1104 guides light generated by the light source 1105 and irradiates it onto the video display unit 1102. The combination of the light guide 1104 and the light source 1105 can also be called a backlight for the video display unit 1102. The light guide 1104 may be configured mainly using glass. The light guide 1104 may be configured mainly using plastic. The light guide 1104 may be configured using a mirror. Various methods are possible for combining the light guide 1104 and the light source 1105. Specific configuration examples of the combination of the light guide 1104 and the light source 1105 will be described in detail later.

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

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

[0070] The mid-air operation detection sensor 1351 only needs to be capable of sensing to detect touch operations with the user's finger on objects displayed as the floating-in-space image 3. Such sensing can be performed using existing technology.

[0071] The aerial operation detection unit 1350 acquires a sensing signal from the aerial operation detection sensor 1351 and, based on the sensing signal, determines whether or not the user's finger has touched an object in the floating-in-space image 3, and calculates the position (contact position) where the user's finger has touched the object. The aerial operation detection unit 1350 is configured, for example, by a circuit such as an FPGA (Field Programmable Gate Array). Some of the functions of the aerial operation detection unit 1350 may be realized by software, for example, by a spatial operation detection program executed by the control unit 1110 or the image 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 image 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 configured to be built into the space-floating image display device 1000, or may be provided externally as separate entities from the space-floating image display device 1000. When provided as separate entities from the space-floating image display device 1000, the aerial operation detection sensor 1351 and the aerial operation detection unit 1350 are configured to be able to transmit information and signals to the space-floating image display device 1000 via a wired or wireless communication connection path or a video signal transmission path. This makes it possible to build a system in which the space-floating image display device 1000, which does not have aerial operation detection function, is used as the main body, and only the aerial operation detection function can be added as an option.

[0073] Also, the aerial operation detection sensor 1351 may be a separate unit, and the aerial operation detection unit 1350 may be built into the space-floating image display device 1000. In cases where it is desired to more freely position the aerial operation detection sensor 1351 relative to the installation position of the space-floating image display device 1000, there is an advantage to a configuration in which only the aerial operation detection sensor 1351 is a separate unit.

[0074] The imaging unit 1180 is a camera with an image sensor, and captures images of the space near the floating-in-space image 3 and / or the face, arms, fingers, etc. of the user 230. A plurality of imaging units 1180 may be provided. For example, the imaging unit 1180 may be provided as a stereo camera. By using a plurality of imaging units 1180, or by using an imaging unit with a depth sensor, the mid-air operation detection unit 1350 can be assisted in detecting the touch operation of the floating-in-space image 3 by the user 230. The imaging unit 1180 may be provided separately from the floating-in-space image display device 1000. When the imaging unit 1180 is provided separately from the floating-in-space image display device 1000, it is sufficient to configure it so that an imaging signal can be transmitted to the floating-in-space image display device 1000 via a wired or wireless communication connection path, etc.

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

[0076] In such a case, the distance between the object and the intrusion detection plane (Floating in Space Image 3) can be calculated by using information such as object depth calculation information based on the captured images of the multiple imaging units 1180 and object depth information from the depth sensor. Then, various information such as the depth calculation information, depth information, and distance between the object and the intrusion detection plane is used for various display controls for the Floating in Space Image 3.

[0077] Furthermore, without using the aerial operation detection sensor 1351, the aerial operation detection unit 1350 may detect a touch operation of the floating-in-space image 3 by the user 230 based on the captured image of the imaging unit 1180. In this case, the imaging unit 1180 may be referred to as an aerial operation detection sensor.

[0078] Furthermore, the imaging unit 1180 may capture an image of the face of the user operating the space-floating image 3, and the control unit 1110 or the like may perform a process to identify the user. Furthermore, in order to determine whether or not there is another person standing around or behind the user operating the space-floating image 3 and peeking at the user's operation of the space-floating image 3, the imaging unit 1180 may capture an image of the user operating the space-floating image 3 and a range including the user's surrounding area.

[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 different from the user's aerial operations (touch operations). Apart from the above-mentioned user touching the space-floating image 3, the operation input unit 1107 may also be used by, for example, an administrator to operate the space-floating image display device 1000.

[0080] The video signal input unit 1131 connects to an external video output device and inputs video data (video signals). The video signal input unit 1131 can be implemented using various digital video input interfaces. For example, the video signal input unit 1131 may be configured with a video input interface conforming to the HDMI (registered trademark) (High-Definition Multimedia Interface) standard, a video input interface conforming to the DVI (Digital Visual Interface) standard, or a video input interface conforming to the DisplayPort standard. Alternatively, an analog video input interface such as analog RGB or composite video may be provided.

[0081] The audio signal input unit 1133 is connected to an external audio output device and inputs audio data (audio signals). The audio signal input unit 1133 may be configured as an HDMI-standard audio input interface, an optical digital terminal interface, a coaxial digital terminal interface, or the like. In the case of an HDMI-standard interface, the video signal input unit 1131 and the audio signal input unit 1133 may be configured as an interface in which a terminal and a cable are integrated.

[0082] The audio output unit 1140 can output audio based on audio data input to the audio signal input unit 1133. The audio output unit 1140 may be configured with a speaker 1140. The audio output unit 1140 may be provided with a section that performs voice synthesis processing, etc. The audio output unit 1140 may also output built-in operation sounds and error warning sounds. Alternatively, the audio output unit 1140 may be configured to output audio as a digital signal to an external device, like the Audio Return Channel function defined in the HDMI standard.

[0083] The audio input unit 1139 may be configured with a microphone 1139. The microphone 1139 is a microphone that collects sounds around the space-floating image display device 1000, converts them into signals, and generates audio signals. The microphone may record a person's voice, such as a user's voice, and the control unit 1110 or the like performs voice recognition processing on the generated audio signal to obtain text information from the audio signal. The audio input unit 1139 may be provided with a part that performs voice recognition processing or the like. Note that the audio output unit 1140, the audio input unit 1139, etc. may be connected as external devices to the space-floating image display device 1000.

[0084] The non-volatile memory 1108 stores various data used by the space floating image display device 1000. The data stored in the non-volatile memory 1108 includes, for example, data for various operations to be displayed on the space floating image 3, display icons, data of objects for the user to operate, layout information, etc. The memory 1109 stores image data to be displayed as the space floating image 3, data for controlling the device, etc.

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

[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, for example, by an Ethernet-standard LAN interface. If the communication unit 1132 has a wireless communication interface, the interface may be configured, for example, by 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] The removable media interface 1134 is an interface for connecting a removable recording medium (removable media). The removable recording medium (removable media) may be composed of a semiconductor device memory such as a solid state drive (SSD), a magnetic recording medium recording device such as a hard disk drive (HDD), or an optical recording medium such as an optical disk. The removable media interface 1134 is capable of reading various information, such as video data, image data, and audio data, recorded on the removable recording medium. The video data, image data, etc. recorded on the removable recording medium are output as the floating image 3 via the video display unit 1102 and the retroreflection unit 1101.

[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 configured with a magnetic recording medium recording device, such as a hard disk drive (HDD), or a semiconductor element memory, such as a solid state drive (SSD). For example, various types of information, such as video data, image data, and audio data, may be recorded in advance in the storage unit 1170 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 an external device, an external server, or the like via the communication unit 1132.

[0089] The video data, image data, etc. recorded in the storage unit 1170 are output as the space floating image 3 via the video display unit 1102 and the retroreflection unit 1101 based on processing by the video control unit 1160. Video data, image data, etc. of display icons, objects for user operation, etc. displayed as the space floating image 3 are also recorded in the storage unit 1170. Layout information of the display icons, objects, etc. displayed as the space floating image 3, and 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 the audio output unit 1140, for example.

[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 a video on the video display unit 1102 (e.g., the liquid crystal display panel 11 of the display device 1 described above), and supplies the video signal to the video display unit 1102. The video control unit 1160 may also be referred to as a video processing circuit, and may be configured with hardware such as an ASIC, FPGA, or video processor. The video control unit 1160 may also be referred to as a video processing unit or image processing unit. The video control unit 1160 performs video switching control, such as determining which video signal to input to the video display unit 1102, between the video signal to be stored in the memory 1109 and the video signal (video data) input to the video signal input unit 1131.

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

[0093] In addition, the image control unit 1160 may generate a superimposed image signal by superimposing the image signal to be stored in the memory 1109 and the image signal input from the image signal input unit 1131, and input the superimposed image signal to the image display unit 1102, thereby controlling the formation of a composite image as a floating image in space 3.

[0094] Furthermore, the video control unit 1160 may control image processing of the video signal input from the video signal input unit 1131, the video signal to be stored in the memory 1109, etc. Examples of image processing include scaling processing that enlarges, reduces, or deforms the image, brightness adjustment processing that changes the brightness, contrast adjustment processing that changes the contrast curve of the image, and Retinex processing that decomposes the image into light components and changes the weighting of each component.

[0095] Furthermore, the video control unit 1160 may perform special effect video processing or the like to assist the user's aerial operation (touch operation) on the video signal input to the video display unit 1102. The special effect 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 on an image of the user captured by the imaging unit 1180. Furthermore, the video control unit 1160 or the like may perform audio control processing when audio is output from the audio output unit 1140 simultaneously with the floating-in-space image 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 configured with a gravity sensor, an acceleration sensor, or a combination of these, and can detect the attitude in which the space-floating image display device 1000 is installed. Based on the attitude detection result of the attitude sensor 1113, the control unit 1110 may control the operation of each connected unit. For example, if an undesirable attitude is detected as the user's usage state, the control unit 1110 may perform control such that the image displayed on the image display unit 1102 is stopped and an error message is displayed to the user. Alternatively, if the attitude sensor 1113 detects a change in the installation attitude of the space-floating image display device 1000, the control unit 1110 may perform control such that the display orientation of the image displayed on the image display unit 1102 is rotated.

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

[0098] <Configuration Example of Space-Floating Image Display Device> Next, a configuration example of the space-floating image display device will be described. The layout of the components of the space-floating image display device according to this embodiment can be various depending on the usage form. Below, the layouts of each of Figs. 4A to 4P will be described. Note that in each of the examples of Figs. 4A to 4P, the thick lines surrounding the components (display device 1, etc.) of the space-floating image display device 1000 indicate an example of the housing structure (housing 1190 in Fig. 3) of the space-floating image display device 1000.

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

[0100] FIG. 4B is a diagram showing an example of the configuration of a space-floating image display device. The space-floating image display device 1000 shown in FIG. 4B is equipped with an optical system corresponding to the optical system of FIG. 2A. The space-floating image display device 1000 shown in FIG. 4B is installed vertically so that the surface on which the space-floating image 3 is formed faces the front of the space-floating image display device 1000 (toward the user 230). That is, in FIG. 4B, the space-floating image display device is installed with the transparent member 100 facing the front of the device (toward the user 230). The space-floating image 3 is formed on the user 230 side of the surface of the transparent member 100 of the space-floating image display device 1000. The light of the space-floating image 3 travels diagonally upward. When the mid-air operation detection sensor 1351 is installed as shown in the figure, it is possible to detect the operation of the space-floating image 3 by the user 230's finger. 4B , the aerial operation detection sensor 1351 can use the reflection of sensing light by the user's nail for touch detection by sensing the finger of the user 230 from above. Generally, the reflectivity of the nail is higher than that of the finger pad, so that this configuration can improve the accuracy of touch detection.

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

[0102] FIG. 4D is a diagram showing an example of the configuration of a space-floating image display device. The space-floating image display device 1000 shown in FIG. 4D is equipped with an optical system corresponding to the optical system of FIG. 2B. The space-floating image display device 1000 shown in FIG. 4D is installed vertically so that the surface on which the space-floating image 3 is formed faces the front of the space-floating image display device 1000 (toward the user 230). That is, in FIG. 4D, the space-floating image display device 1000 is installed with the transparent member 100 facing the front of the device (toward the user 230). The space-floating image 3 is formed on the user 230 side of the surface of the transparent member 100 of the space-floating image display device 1000. The light of the space-floating image 3 travels diagonally upward. If the mid-air operation detection sensor 1351 is installed as shown in the figure, it can detect the operation of the space-floating image 3 by the user 230's finger. 4D , the aerial operation detection sensor 1351 can use the reflection of sensing light by the user's nail for touch detection by sensing the finger of the user 230 from above. Generally, the reflectivity of the nail is higher than that of the finger pad, so that this configuration can improve the accuracy of touch detection.

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

[0104] FIG. 4F is a diagram showing an example of the configuration of a space-floating image display device. The space-floating image display device 1000 shown in FIG. 4F is equipped with an optical system corresponding to the optical system of FIG. 2C. The space-floating image display device 1000 shown in FIG. 4F is installed vertically so that the surface on which the space-floating image 3 is formed faces the front of the space-floating image display device 1000 (toward the user 230). That is, in FIG. 4F, the space-floating image display device 1000 is installed with the transparent member 100 facing the front of the device (toward the user 230). The space-floating image 3 is formed on the user 230 side of the surface of the transparent member 100 of the space-floating image display device 1000. The light of the space-floating image 3 travels toward the user. If the mid-air operation detection sensor 1351 is installed as shown in the figure, it can detect the operation of the space-floating image 3 by the user 230's finger.

[0105] FIG. 4G is a diagram showing an example of the configuration of a space-floating image display device. The space-floating image display device 1000 shown in FIG. 4G is equipped with an optical system corresponding to the optical system shown in FIG. 2C. In the optical systems of the space-floating image display devices shown in FIGS. 4A to 4F, the central optical path of the image light emitted from the display device 1 was on the yz plane. That is, in the optical systems of the space-floating image display devices shown in FIGS. 4A to 4F, the image light traveled in the front-to-back and up-to-down directions as seen from the user. In contrast, in the optical system of the space-floating image display device shown in FIG. 4G, the central optical path of the image light emitted from the display device 1 is on the xy plane. That is, in the optical system of the space-floating image display device shown in FIG. 4G, the image light travels in the left-to-right and front-to-back directions as seen from the user. In the space-floating image display device 1000 shown in FIG. 4G, the surface on which the space-floating image 3 is formed is installed so that it faces the front of the device (toward the user 230). 4G, the space-floating image display device 1000 has the transparent member 100 installed on the front side of the device (toward the user 230). The space-floating image 3 is formed on the user side of the surface of the transparent member 100 of the space-floating image display device 1000. The light of the space-floating image 3 travels towards the user. If the mid-air operation detection sensor 1351 is installed as shown in the figure, it can detect the operation of the space-floating image 3 by the finger of the user 230.

[0106] 4H is a diagram showing an example of the configuration of a space-floating image display device. The space-floating image display device 1000 of FIG. 4H differs from the space-floating image display device of FIG. 4G in that it has a window with a transparent plate 100B made of glass or plastic on the back of the device (opposite the position where the user 230 views the space-floating image 3, i.e., opposite the traveling direction of the image light of the space-floating image 3 toward the user 230). The rest of the configuration is the same as the space-floating image display device of FIG. 4G , so repeated explanations will be omitted. The space-floating image display device 1000 of FIG. 4H has a window with a transparent plate 100B on the opposite side of the traveling direction of the image light of the space-floating image 3 from the space-floating image 3. Therefore, when the user 230 views the space-floating image 3, they can recognize the scenery behind the space-floating image display device 1000 as the background of the space-floating image 3. Therefore, the user 230 can perceive the space floating image 3 as floating in the air in front of the scenery behind the space floating image display device 1000. This can further emphasize the floating feeling of the space floating image 3.

[0107] Depending on the polarization distribution of the image light output from the display device 1 and the performance of the polarization separation member 101B, a portion of the image light output from the display device 1 may be reflected by the polarization separation member 101B and head toward the transparent plate 100B. Depending on the coating performance of the surface of the transparent plate 100B, this light may be reflected again by the surface of the transparent plate 100B and may be visually recognized by the user 230 as stray light. Therefore, in order to prevent this stray light, the transparent plate 100B may not be provided in the window on the back of the space-floating image display device 1000.

[0108] Fig. 4I is a diagram showing an example of the configuration of a space-floating image display device. The space-floating image display device 1000 of Fig. 4I differs from the space-floating image display device of Fig. 4H in that a light-blocking door 1410 is provided in the window of the transparent plate 100B located on the back of the device (opposite the position where the user 230 views the space-floating image 3). The rest of the configuration is the same as that of the space-floating image display device of Fig. 4H, so repeated explanations will be omitted.

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

[0110] For example, if the view seen through the window of the transparent plate 100B of the space-floating image display device 1000 is outdoors, the brightness of sunlight varies depending on the weather. When the outdoor sunlight is strong, the background of the space-floating image 3 may become too bright, reducing the user 230's visibility of the space-floating image 3. In such a case, by moving (sliding), rotating, or attaching the light-shielding plate of the opening / closing door 1410 to block the light from the rear window, the background of the space-floating image 3 becomes dark, thereby relatively increasing the visibility of the space-floating image 3. Such a blocking operation by the light-shielding plate of the opening / closing door 1410 may be performed directly by the force of the user 230's hand. In response to an operation input via the operation input unit 1107 of FIG. 3 , the control unit 1110 may control a motor (not shown) to perform the blocking operation by the light-shielding plate of the opening / closing door 1410.

[0111] An illuminance sensor may be provided on the rear side (opposite the user 230) of the space-floating image display device 1000, such as near the rear window, to measure the brightness of the space beyond the rear window. In this case, the control unit 1110 of Fig. 3 may control a motor (not shown) to perform the opening and closing operation of the light blocking plate of the opening and closing door 1410 according to the detection result of the illuminance sensor. By controlling the opening and closing operation of the light blocking plate of the opening and closing door 1410 in this way, it is possible to more suitably maintain the visibility of the space-floating image 3, even if the user 230 does not manually open or close the light blocking plate of the opening and closing door 1410.

[0112] Furthermore, the light blocking plate provided by the opening and closing door 1410 may be manually detachable. Depending on the intended use and installation environment of the space floating image display device 1000, the user can select whether to leave the rear window open or in a light blocking state. If it is planned to use the rear window in a light blocking state for a long period of time, the detachable light blocking plate can be fixed in the light blocking state. Furthermore, if it is planned to use the rear window in an open state for a long period of time, the detachable light blocking plate can be left detached. The light blocking plate may be attached and detached using screws, a hook structure, or a fitting structure.

[0113] 4I, depending on the polarization distribution of the image light output from the display device 1 and the performance of the polarization separation member 101B, a portion of the image light output from the display device 1 may be reflected by the polarization separation member 101B and directed toward the transparent plate 100B. Depending on the coating performance of the surface of the transparent plate 100B, this light may be reflected again by the surface of the transparent plate 100B and be visible to the user 230 as stray light. Therefore, in order to prevent this stray light, the window on the back of the space-floating image display device 1000 may not be provided with the transparent plate 100B. The above-described opening / closing door 1410 may be provided in a window that does not have the transparent plate 100B. To prevent this stray light, it is desirable that the inner surface of the housing of the light-shielding plate of the above-described opening / closing door 1410 have a coating or material with low light reflectance.

[0114] FIG. 4J is a diagram showing an example of the configuration of a space-floating image display device. The space-floating image display device 1000 of FIG. 4J differs from the space-floating image display device of FIG. 4H in that an electronically controlled transmittance variable device 1620 is disposed on the rear side window instead of the transparent plate 100B made of glass or plastic. The other components are the same as those of the space-floating image display device of FIG. 4H , so repeated explanations will be omitted. An example of the electronically controlled transmittance variable device 1620 is a liquid crystal shutter. Although the electronically controlled transmittance variable device 1620 is not shown in FIG. 3 , if it is provided, it may be configured as one component of the space-floating image display device 1000 of FIG. 3 , and be connected to other processing units such as the control unit 1110.

[0115] The liquid crystal shutter can control the light transmittance by controlling the voltage of the liquid crystal element sandwiched between two polarizing plates. Therefore, if the liquid crystal shutter is controlled to increase the transmittance, the scenery through the rear window can be seen through the background of the floating image 3. On the other hand, if the liquid crystal shutter is controlled to decrease the transmittance, the scenery through the rear window can be hidden as the background of the floating image 3.

[0116] Furthermore, since the liquid crystal shutter can control halftones, it can also be set to a state of transmittance of 50% or the like. For example, the control unit 1110 can control the transmittance of the electronically controlled transmittance variable device 1620 in response to an operation input via the operation input unit 1107 in Fig. 3. With this configuration, in cases where a viewer wants to see the scenery through the rear window as the background of the Space Floating Image 3, but the scenery through the rear window as the background is too bright and reduces the visibility of the Space Floating Image 3, it is possible to adjust the transmittance of the electronically controlled transmittance variable device 1620 and thereby adjust the visibility of the Space Floating Image 3.

[0117] In addition, an illuminance sensor may be provided on the rear side (opposite the user 230) of the space-floating image display device 1000, such as near the rear window, to measure the brightness of the space beyond the rear window. In this case, the control unit 1110 of Fig. 3 controls the transmittance of the electronically controlled transmittance variable device 1620 according to the detection result of the illuminance sensor. In this way, even if the user 230 does not perform an operation input via the operation input unit 1107 of Fig. 3, the transmittance of the electronically controlled transmittance variable device 1620 can be adjusted according to the brightness of the space beyond the rear window, making it possible to more suitably maintain the visibility of the space-floating image 3.

[0118] In the above example, a liquid crystal shutter has been described as an example of the electronically controlled transmittance varying device 1620. However, electronic paper may be used as another example of the electronically controlled transmittance varying device 1620. The same effect as described above can be obtained when electronic paper is used. Furthermore, electronic paper consumes very little power to maintain a halftone state. Therefore, a space floating image display device with lower power consumption can be realized compared to when a liquid crystal shutter is used.

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

[0120] In the space-floating image display device 1000 of FIG. 4K, an image luminous flux passes through the display surface of the transmissive self-luminous image display device 1650, and then a space-floating image 3 is formed outside the space-floating image display device 1000. That is, when an image is displayed on the transmissive self-luminous image display device 1650, which is a two-dimensional flat display, the space-floating image 3 can be displayed as a pop-up image further in front of the image displayed on the transmissive self-luminous image display device 1650. In this case, the user 230 can simultaneously view two images at different depth positions. The transmissive self-luminous image display device 1650 may be configured using existing technology, such as a transmissive organic EL panel, as disclosed in, for example, Japanese Patent Application Laid-Open No. 2014-216761. Incidentally, when the transmissive self-luminous image display device 1650 is provided, it may be configured to be connected to other processing units, such as the control unit 1110, as a component of the space-floating image display device 1000 of FIG. 3.

[0121] Here, if the transmissive self-luminous image display device 1650 displays both the background and an object such as a character, and then displays only the object such as the character moving into the floating image 3 in front, it is possible to provide the user 230 with a more effective surprise-like image experience.

[0122] Furthermore, if the interior of the space-floating image display device 1000 (housing 1190) is kept light-shielded, the background of the transmissive self-luminous image display device 1650 will be sufficiently dark. Therefore, when no image is displayed on the display device 1 or the light source of the display device 1 is turned off and an image is displayed only on the transmissive self-luminous image display device 1650, the transmissive self-luminous image display device 1650 appears to the user 230 as a normal two-dimensional flat display, rather than a transmissive display. Note that, since the space-floating image 3 in the embodiment of the present invention is displayed as a real optical image in a space without a screen, if the light source of the display device 1 is turned off, the intended display position of the space-floating image 3 becomes empty space. Therefore, when the transmissive self-luminous image display device 1650 is used to display an image as if it were a normal two-dimensional flat display, characters, objects, etc., can be suddenly displayed in the air as the space-floating image 3, providing the user 230 with a more effective and surprising video experience.

[0123] Note that the darker the interior of the space-floating image display device 1000, the more the transmissive self-luminous image display device 1650 appears like a two-dimensional flat display. Therefore, an absorptive polarizer (not shown) that transmits the polarized light of the image light reflected by the polarization separation member 101B and absorbs polarized light that is 90° out of phase with the polarized light may be provided on the interior surface of the transmissive self-luminous image display device 1650 (the surface on which the image light reflected by the polarization separation member 101B enters the transmissive self-luminous image display device 1650, i.e., the surface of the transmissive self-luminous image display device 1650 opposite the space-floating image 3). While this does not have a significant effect on the image light that forms the space-floating image 3, it can significantly reduce the light that enters the space-floating image display device 1000 from the outside through the transmissive self-luminous image display device 1650, making the interior of the space-floating image display device 1000 darker, which is preferable.

[0124] 4L is a diagram showing an example of the configuration of a space-floating image display device. The space-floating image display device 1000 of FIG. 4L is a modified example of the space-floating image display device of FIG. 4K. The orientation of the components in the space-floating image display device 1000 is different from that of the space-floating image display device of FIG. 4K, and is closer to the arrangement of the space-floating image display device of FIG. 4F. The functions and operations of each component are the same as those of the space-floating image display device of FIG. 4K, so repeated explanations will be omitted.

[0125] In the space-floating image display device of FIG. 4L, after the luminous flux of image light passes through the transmissive self-luminous image display device 1650, a space-floating image 3 is formed on the user 230 side of the transmissive self-luminous image display device 1650.

[0126] In both the example of the space-floating image display device of FIG. 4K and the example of the space-floating image display device of FIG. 4L, the space-floating image 3 is displayed superimposed on the image of the transmissive self-luminous image display device 1650 as seen by the user 230. Here, the position of the space-floating image 3 and the position of the image of the transmissive self-luminous image display device 1650 are configured to have a difference in the depth direction. Therefore, when the user 230 moves his / her head (position of viewpoint), the depth of the two images can be recognized by parallax. Therefore, by displaying two images at different depth positions, it is possible to provide the user with a more suitable three-dimensional image experience with the naked eye without the need for stereoscopic glasses or the like.

[0127] Fig. 4M is a diagram showing an example of the configuration of a space-floating image display device. The space-floating image display device 1000 of Fig. 4M has a second display device 1680 provided on the far side (for example, the back panel of the housing 1190) as seen from the user 230 relative to the polarization separation member 101B of the space-floating image display device of Fig. 4G. The other configurations are the same as those of the space-floating image display device of Fig. 4G, so repeated explanations will be omitted.

[0128] In the configuration example shown in Fig. 4M, the second display device 1680 is provided behind the display position of the space-floating image 3, and the image display surface is directed toward the space-floating image 3. With this configuration, from the user 230's perspective, the image of the second display device 1680 and the image of the space-floating image 3, which are displayed at two different depth positions, can be viewed superimposed on each other. In other words, the second display device 1680 can be said to be arranged so as to display an image toward the user 230 who views the space-floating image 3. When the second display device 1680 is provided, it may be configured to be connected to other processing units such as the control unit 1110 as one component of the space-floating image display device 1000 of Fig. 3.

[0129] Note that the image light of the second display device 1680 of the space-floating image display device 1000 of FIG. 4M is viewed by the user 230 after passing through the polarization separation member 101B. Therefore, in order for the image light of the second display device 1680 to more suitably pass through the polarization separation member 101B, it is desirable that the image light output from the second display device 1680 be polarized with a polarization in a vibration direction that the polarization separation member 101B more suitably transmits. In other words, it is desirable that the image light be polarized with a polarization in the same vibration direction as the polarization of the image light output from the display device 1. For example, if the image light output from the display device 1 is S-polarized, it is desirable that the image light output from the second display device 1680 is also S-polarized. Furthermore, if the image light output from the display device 1 is P-polarized, it is desirable that the image light output from the second display device 1680 is also P-polarized.

[0130] The example of the space-floating image display device of FIG. 4M also has the same effect as the example of the space-floating image display device of FIG. 4K and the example of the space-floating image display device of FIG. 4L in that a second image is displayed behind the space-floating image 3. However, unlike the example of the space-floating image display device of FIG. 4K and the example of the space-floating image display device of FIG. 4L, in the example of the space-floating image display device of FIG. 4M, the luminous flux of image light for forming the space-floating image 3 does not pass through the second display device 1680. Therefore, the second display device 1680 does not need to be a transmissive self-luminous image display device, but may be a liquid crystal display, which is a two-dimensional flat display. The second display device 1680 may also be an organic EL display. Therefore, in the example of the space-floating image display device of FIG. 4M, it is possible to realize the space-floating image display device 1000 at a lower cost than the example of the space-floating image display device of FIG. 4K and the example of the space-floating image display device of FIG. 4L.

[0131] Here, depending on the polarization distribution of the image light output from the display device 1 and the performance of the polarization separation member 101B, there is a possibility that part of the image light output from the display device 1 will be reflected by the polarization separation member 101B and head toward the second display device 1680. This light (part of the image light) may be reflected again by the surface of the second display device 1680 and may be visually recognized by the user as stray light.

[0132] Therefore, to prevent this stray light, an absorptive polarizer may be provided on the surface of the second display device 1680. In this case, the absorptive polarizer may be an absorptive polarizer that transmits the polarized waves of the image light output from the second display device 1680 and absorbs polarized waves that are 90° out of phase with the polarized waves of the image light output from the second display device 1680. If the second display device 1680 is a liquid crystal display, an absorptive polarizer is also present on the image output side inside the liquid crystal display. However, if a cover glass (cover glass on the image display surface side) is further provided on the output surface of the absorptive polarizer on the image output side inside the liquid crystal display, it is not possible to prevent stray light caused by reflection of the cover glass by light from outside the liquid crystal display. Therefore, it is necessary to separately provide the above-mentioned absorptive polarizer on the surface of the cover glass.

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

[0134] Furthermore, if the second display device 1680 displays both the background and an object such as a character, and then displays only the object such as the character moving into the floating image 3 in front, it is possible to provide the user 230 with a more effective surprise visual experience.

[0135] Next, Fig. 4N is a diagram showing an example of the configuration of a space-floating image display device. The space-floating image display device 1000 of Fig. 4N is a space-floating image display device that employs the optical system of Fig. 2D. In the space-floating image display device 1000 of Fig. 4N, similar to the examples of the space-floating image display device that employ the optical systems of Figs. 2A to 2C, image light that has passed through a transparent member 100 is formed in the air as a space-floating image 3. In addition, using sensing light from an aerial operation detection sensor 1351 that is located on the back side of the transparent member 100 as seen from the user, it is possible to detect operation of the space-floating image 3 by the user's finger 9004.

[0136] In both the example of the space-floating image display device employing the optical systems of FIGS. 2A to 2C and the example of the space-floating image display device employing the optical system of FIG. 2D, the space-floating image 3 is formed in front of the transparent member 100, and the operation of the space-floating image 3 by the user's finger can be detected using the sensing light of the mid-air operation detection sensor 1351 located on the back side of the transparent member 100 as seen by the user.

[0137] The space-floating image display device employing the optical system of Fig. 2D has a different optical system from the space-floating image display device in which the optical system of Fig. 2A to Fig. 2C is arranged on the back side of the transparent member 100 as seen from the user. However, the usability of the space-floating image display device employing the optical system of Fig. 2D as seen from the user is almost the same as that of the space-floating image display device employing the optical system of Fig. 2A to Fig. 2C.

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

[0139] 4O, the space-floating image display device 1000 has a transparent member 100 installed on the top surface of the device. The space-floating image 3 is formed above the surface of the transparent member 100 of the space-floating image display device 1000. The light of the space-floating image 3 travels diagonally upward. When the mid-air operation detection sensor 1351 is provided as shown in the figure, it can detect the operation of the space-floating image 3 by the finger of the user 230.

[0140] Here, the configuration of Fig. 4O will be compared with the configuration of Fig. 4A to confirm the differences. In Fig. 4A, the display device 1 and the space-floating image 3 are in a plane-symmetrical relationship with respect to the plane of the polarization separation member 101. In contrast, in Fig. 4O, the display device 1 and the space-floating image 3 are in a plane-symmetrical relationship with respect to the plane of the retroreflector 5. Furthermore, the configuration of Fig. 4A includes the retroreflector 2 and the λ / 4 plate 21, but these are not present in Fig. 4O. Furthermore, while the presence of the absorbing polarizer 12 is more preferable in Fig. 4A, the absorbing polarizer 12 is not particularly necessary in Fig. 4O.

[0141] To replace the optical system of FIG. 2A in the configuration of FIG. 4A with the optical system of FIG. 2D and convert it into the configuration of FIG. 4O, the following can be done. That is, the polarization separation member 101 in the configuration of FIG. 4A is replaced with the retroreflector 5, and the retroreflector 2 and the λ / 4 plate 21 are removed from the configuration of FIG. 4A. The absorptive polarizer 12 is optional. By making a substitution based on this idea, the optical system of FIGS. 2A to 2C installed in the configuration of the space-floating image display device of FIGS. 4A to 4G can be replaced with the optical system of FIG. 2D, and the space-floating image display device can be replaced with the optical system of FIG. 2D. In this case, the polarization separation member 101 in FIGS. 4A and 4B is replaced with the retroreflector 5, and the polarization separation member 101B in FIGS. 4C to 4G is replaced with the retroreflector 5.

[0142] For example, FIG. 4P is a diagram showing an example of the configuration of a space-floating image display device. The space-floating image display device 1000 shown in FIG. 4P is equipped with an optical system corresponding to the optical system shown in FIG. 2D. FIG. 4P shows the configuration of the space-floating image display device of FIG. 4B, with the optical system shown in FIG. 2A replaced with the optical system shown in FIG. 2D. The space-floating image display device 1000 shown in FIG. 4P is installed vertically so that the surface on which the space-floating image 3 is formed faces the front of the space-floating image display device 1000 (toward the user 230). That is, in FIG. 4P, the space-floating image display device is installed with the transparent member 100 facing the front of the device (toward the user 230). The space-floating image 3 is formed on the user 230 side of the surface of the transparent member 100 of the space-floating image display device 1000. The light of the space-floating image 3 travels diagonally upward. When the mid-air operation detection sensor 1351 is installed as shown in the figure, it is possible to detect the operation of the space-floating image 3 by the user 230's finger. 4P, the aerial operation detection sensor 1351 can use the reflection of sensing light by the user's nail for touch detection by sensing the finger of the user 230 from above. Generally, the reflectivity of the nail is higher than that of the finger pad, so that this configuration can improve the accuracy of touch detection.

[0143] According to the configuration of the space floating image display device of FIGS. 4N to 4P, it is possible to realize a user-friendly space floating image display device using the optical system of FIG. 2D.

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

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

[0146] 5, the display device 1 is configured with a light source device 13 and a liquid crystal display panel 11, a light redirection panel 54 that controls the directional characteristics of the light beam emitted from the light source device 13, and, if necessary, a narrow-angle diffuser (not shown). That is, polarizing plates are provided on both sides of the liquid crystal display panel 11, and as indicated by arrow 30 in FIG. 5, image light of a specific polarization is emitted with its intensity modulated by a video signal. This allows the desired image to be projected as highly directional (linear) light of a specific polarization via the light redirection panel 54 toward the retroreflector 2, which then reflects the light toward the eyes of a monitor outside the store (space) shown in FIG. 1, forming the floating image 3. A protective cover 50 (see FIGS. 6 and 7) may be provided on the surface of the light redirection panel 54.

[0147] <Display Device Example 1> FIG. 6 shows an example of a specific configuration of the display device 1. In FIG. 6, a liquid crystal display panel 11 and a light direction conversion panel 54 are arranged on the light source device 13 shown in FIG. 5. This light source device 13 is configured, for example, by housing LED elements 201 and a light guide 203 inside a plastic case or the like. As shown in FIG. 5 and other figures, the end surface of the light guide 203 has a lens-like shape whose cross-sectional area gradually increases toward the light receiving section in order to convert the divergent light from each LED element 201 into a substantially parallel beam. The lens-like shape gradually reduces the divergence angle through multiple total reflections as the light propagates through the light guide 203. The liquid crystal display panel 11 constituting the display device 1 is attached to the top surface of the display device 1. Furthermore, an LED substrate 202 mounting the LED elements 201, which are semiconductor light sources, and their associated control circuits is attached to one side surface of the light source device 13 (the left end surface in this example). A heat sink, a component for cooling the heat generated by the LED elements 201 and the control circuit, may be attached to the outer surface of the LED substrate 202.

[0148] Furthermore, a frame (not shown) for the liquid crystal display panel 11 is attached to the top surface of the case of the light source device 13. The frame (not shown) for the liquid crystal display panel 11 is also attached to the frame, and an FPC (Flexible Printed Circuit) (not shown) electrically connected to the liquid crystal display panel 11 is also attached. That is, the liquid crystal display panel 11, which is the image display element 11, generates a display image by modulating the intensity of transmitted light in conjunction with the LED elements 201, which are solid-state light sources, based on a control signal from a control circuit (image control unit 1160 in FIG. 3 ) constituting the electronic device. The generated image light has a narrow diffusion angle and contains only specific polarization components, resulting in a novel image display device similar to a surface-emitting laser image source driven by a video signal. Currently, it is technically and safety-wise impossible to obtain a laser beam of the same size as the image obtained by the display device 1 described above using a laser device. Therefore, in this embodiment, light similar to the surface-emitting laser image light described above is obtained from a beam of light from a general light source, for example, an LED element.

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

[0150] Each light guide 203 is formed of a translucent resin such as acrylic. The LED light-receiving surface at the end of the light guide 203 has a cone-shaped outer periphery obtained by rotating a parabolic cross section, with a centrally-convex concave portion (i.e., a convex lens surface) at the top, and a centrally-convex convex lens surface (or a concave lens surface) at the flat surface (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 forming a cone-shaped outer periphery, and is set within an angle range that allows total reflection of the light emitted from the LED element toward the periphery, or a reflective surface is formed.

[0151] On the other hand, the LED elements 201 are arranged at predetermined positions on the surface of the circuit board, that is, the LED substrate 202. The LED substrate 202 is arranged and fixed so that the LED elements 201 on the surface are positioned in the center of the recessed portion described above with respect to the light-receiving end surface 203a, that is, the LED collimator.

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

[0153] As described above, the light source device 13 is configured by attaching a light source unit having a plurality of LED elements 201 arranged as light sources to the light-receiving end surface 203a, which is a light-receiving section provided on the end surface of the light guide 203, and the divergent light beams from the LED elements 201 are converted into approximately parallel light by the lens shape of the light-receiving end surface 203a of the light guide 203, which is guided inside the light guide 203 as shown by the arrow, and is emitted by the light beam direction conversion means 204 toward the liquid crystal display panel 11, which is arranged approximately parallel to the light guide 203. By optimizing the distribution (in other words, density) of the light beam direction conversion means 204 depending on the shape of the inside or surface of the light guide 203, it is possible to control the uniformity of the light beam incident on the liquid crystal display panel 11.

[0154] The light beam direction conversion means 204 described above emits the light beam propagated inside the light guide 203 toward the liquid crystal display panel 11 disposed approximately parallel to the light guide 203, by using the shape of the surface of the light guide 203 or by providing a portion with a different refractive index inside the light guide 203. At this time, when the liquid crystal display panel 11 is faced directly at the center of the screen and the viewpoint is positioned at the same position as the diagonal dimension of the screen, and the brightness at the center of the screen and the brightness at the periphery of the screen are compared, if the relative brightness ratio is 20% or more, there is no practical problem, and if it exceeds 30%, it will be an even better characteristic.

[0155] 6 is a cross-sectional layout diagram illustrating the configuration and operation of a light source of this embodiment that performs polarization conversion in light source device 13 including light guide 203 and LED element 201 described above. In Fig. 6, light source device 13 is composed of light guide 203 formed of, for example, plastic or the like and having light beam direction conversion means 204 on its surface or inside, LED element 201 as a light source, reflective sheet 205, retardation plate 206, lenticular lens, etc. Attached to the top surface of light source device 13 is liquid crystal display panel 11 that has polarizing plates on the light source light entrance surface and the image light exit surface.

[0156] Furthermore, a film- or sheet-like reflective polarizing plate 49 is provided on the light source light incidence surface (the lower surface in the figure) of the liquid crystal display panel 11 corresponding to the light source device 13, selectively reflecting one polarized wave (e.g., P wave) 212 of the natural light beam 210 emitted from the LED element 201. The reflected light is reflected again by a reflective sheet 205 provided on one surface (the lower surface in the figure) of the light guide 203 and directed toward the liquid crystal display panel 11. Therefore, a retardation plate (λ / 4 plate) is provided between the reflective sheet 205 and the light guide 203 or between the light guide 203 and the reflective polarizing plate 49. The reflected light (reflected light beam) is reflected by the reflective sheet 205 and passes through the retardation plate (λ / 4 plate) a total of two times, thereby converting it from P-polarized light to S-polarized light. This improves the utilization efficiency of the light source light as image light. The image light beam, the light intensity of which has been modulated by the image signal in the liquid crystal display panel 11, is emitted as shown by the arrow 213 in Fig. 6 and enters the retroreflector 2. After being reflected by the retroreflector 2, a real image, a floating image in space, can be obtained.

[0157] 7 is a cross-sectional layout diagram illustrating the configuration and operation of a light source of this embodiment that performs polarization conversion in a light source device 13 including a light guide 203 and LED elements 201, similar to Fig. 6. The light source device 13 is similarly composed of a light guide 203 formed of, for example, plastic, on the surface of which or inside which a light beam direction conversion means 204 is provided, an LED element 201 as a light source, a reflective sheet 205, a retardation plate 206, a lenticular lens, etc. A liquid crystal display panel 11 having polarizing plates on the light source light entrance surface and the image light exit surface is attached to the upper surface of the light source device 13.

[0158] Furthermore, a film- or sheet-like reflective polarizing plate 49 is provided on the light source light incidence surface (the lower surface in the figure) of the liquid crystal display panel 11 corresponding to the light source device 13, selectively reflecting one polarized wave (e.g., S wave) 211 of the natural light beam 210 emitted from the LED element 201. That is, in the example of FIG. 7 , the selective reflection characteristics of the reflective polarizing plate 49 are different from those in FIG. 7 . The reflected light is reflected by a reflective sheet 205 provided on one surface (the lower surface in the figure) of the light guide 203 and returns to the liquid crystal display panel 11. A retardation plate (λ / 4 plate) is provided between the reflective sheet 205 and the light guide 203 or between the light guide 203 and the reflective polarizing plate 49. The reflected light (reflected light beam) is reflected by the reflective sheet 205 and passes through the retardation plate (λ / 4 plate) twice, converting it from S-polarized light to P-polarized light. This improves the utilization efficiency of the light source light as image light. The image light beam, whose light intensity has been modulated by the image signal in the liquid crystal display panel 11, is emitted as shown by the arrow 214 in Fig. 7 and enters the retroreflector 2. After being reflected by the retroreflector 2, a real image, that is, 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 function of the polarizer provided on the light incident surface of the corresponding liquid crystal display panel 11, a reflective polarizer reflects the polarized light component on one side. Therefore, the theoretically obtainable contrast ratio is the reciprocal of the cross transmittance of the reflective polarizer multiplied by the reciprocal of the cross transmittance obtained by the two polarizers attached to the liquid crystal display panel 11. This results in high contrast performance. In fact, experiments have confirmed that the contrast performance of the displayed image is improved by more than 10 times. As a result, high-quality images comparable to those of self-luminous organic EL displays are obtained.

[0160] <Example 2 of Display Device> 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 configured by housing LEDs, a collimator, a composite diffusion block, a light guide, etc. in a case made of, for example, plastic, and a liquid crystal display panel 11 is attached to the upper surface of the light source device 13. Also, LED elements 201, which are semiconductor light sources, and an LED board 202, on which a control circuit for the LED elements 201 is mounted, are attached to one side of the case of the light source device 13, and a heat sink 103, which is a member for cooling heat generated by the LED elements 201 and the control circuit, is attached to the outer surface of the LED board 202.

[0161] The liquid crystal display panel frame attached to the top surface of the case of the light source device 13 is configured to have attached thereto the liquid crystal display panel 11 attached to the frame, and further to have attached thereto an FPC 403 electrically connected to the liquid crystal display panel 11. That is, the liquid crystal display panel 11, which is the image display element 11, generates a display image together with the LED elements 201, which are solid-state light sources, by modulating the intensity of transmitted light based on a control signal from a control circuit (not shown) that constitutes the electronic device.

[0162] <Display Device Example 3> Next, another example of the specific configuration of the display device 1 (Display Device Example 3) will be described with reference to Fig. 9 . The light source device of this display device 1 converts a divergent beam of light (a mixture of P-polarized and S-polarized light) from the LED 201 into a substantially parallel beam by a collimator (LED collimator) 18, and reflects the parallel beam 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 disposed between the liquid crystal display panel 11 and the reflective light guide 304. The reflective polarizer 49 transmits light of a specific polarization (e.g., P-polarized light) and causes the transmitted polarized light to be incident on the liquid crystal display panel 11. Here, light polarized other than the specific polarization (e.g., S-polarized light) is reflected by the reflective polarizer 49 and directed again toward the reflective light guide 304.

[0163] The reflective polarizing plate 49 is installed at an angle with respect to the liquid crystal display panel 11 so that the reflective polarizing plate 49 is not perpendicular to the chief ray of light from the reflective surface of the reflective light guide 304. The chief ray of light reflected by the reflective polarizing plate 49 is incident on the transmission surface of the reflective light guide 304. The light that has entered the transmission surface of the reflective light guide 304 passes through the back surface of the reflective light guide 304, passes through the λ / 4 plate 270 which is a retardation plate, and is reflected by the reflector 271. The light reflected by the reflector 271 passes through the λ / 4 plate 270 again, and passes through the transmission surface of the reflective light guide 304. The light that has passed through the transmission surface of the reflective light guide 304 is incident on the reflective polarizing plate 49 again.

[0164] At this time, the light that re-enters the reflective polarizing plate 49 has passed through the λ / 4 plate 270 twice, and therefore its polarization has been converted to a polarization (for example, P-polarized light) that is transmitted through the reflective polarizing plate 49. Therefore, the light whose polarization has been converted passes through the reflective polarizing plate 49 and enters the liquid crystal display panel 11. Note that, with regard to the polarization design related to the polarization conversion, the polarization may be configured in reverse from the above explanation (S-polarized light and P-polarized light may be reversed).

[0165] As a result, the light from the LEDs 201 is aligned to a specific polarization (for example, P polarization), enters the liquid crystal display panel 11, and is brightness-modulated in accordance with the video signal to display an image on the panel surface. As in the above example, the light source has a plurality of LEDs 201, which are attached to predetermined positions relative to the corresponding collimators 18 of the plurality of collimators 18. However, since Figure 9 is a vertical cross section, only one LED 201 and one collimator 18 are shown.

[0166] Each collimator 18 is formed of a translucent resin such as acrylic or glass. The collimator 18 may have a cone-shaped outer circumferential surface obtained by rotating a parabolic cross section. The collimator 18 may have a concave portion with a convex portion (i.e., a convex lens surface) formed in the center of the apex (the side facing the LED substrate 202). The collimator 18 may have a convex lens surface (or a concave lens surface) protruding outward in the center of the flat portion (the side opposite the apex). The parabolic surface forming the cone-shaped outer circumferential surface of the collimator 18 is set within an angle range that allows total reflection of the light emitted from the LED 201 toward the periphery, or a reflective surface is formed therein.

[0167] The LEDs 201 are arranged at predetermined positions on the surface of the circuit board, that is, the LED board 202. The LED board 202 is arranged and fixed to the collimator 18 so that the LEDs 201 on the surface are positioned at the center of the apex of the conical convex shape (or in the concave portion if the apex has a concave portion).

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

[0169] Furthermore, the light converted into approximately parallel light by the collimator 18 shown in FIG. 9 is reflected by the reflective light guide 304. Of this light, light of a specific polarization passes through the reflective polarizer 49 due to the action of the reflective polarizer 49, while light of the other polarization reflected by the action of the reflective polarizer 49 passes through the light guide 304 again. The light is reflected by the reflector 271 located opposite the liquid crystal display panel 11 with respect to the reflective light guide 304. At this time, the light is polarized and converted by passing twice through the λ / 4 plate 270, which is a retardation plate. The light reflected by the reflector 271 passes through the light guide 304 again and enters the reflective polarizer 49 provided on the opposite surface. Since the incident light has been polarized and converted, it passes through the reflective polarizer 49 and enters the liquid crystal display panel 11 with its polarization direction aligned. As a result, all of the light from the light source can be used, doubling the geometrical optical utilization efficiency of light. Furthermore, since the degree of polarization (extinction ratio) of the reflective polarizer 49 is also included in the extinction ratio of the entire system, the use of the light source device of this embodiment significantly improves the contrast ratio of the entire display device. Adjusting the surface roughness of the reflective surface of the reflective light guide 304 and the surface roughness of the reflector 271 allows adjustment of the angle of light reflection and diffusion at each reflective surface. The surface roughness of the reflective surface of the reflective light guide 304 and the surface roughness of the reflector 271 can be adjusted for each design to optimize the uniformity of the light incident on the liquid crystal display panel 11.

[0170] It should be noted that the λ / 4 plate 270, which is the retardation plate in Fig. 9, does not necessarily have to have a phase difference of λ / 4 with respect to polarized light that is perpendicularly incident on the λ / 4 plate 270. In the configuration of Fig. 9, any retardation plate may be used as long as the phase changes by 90° (λ / 2) when polarized light passes through it twice. The thickness of the retardation plate may be adjusted according to the incident angle distribution of the polarized light.

[0171] <Display Device Example 4> Another example (Display Device Example 4) of the configuration of the optical system, such as the light source device of the display device 1, will be described with reference to Fig. 10 . Display Device Example 4 is a configuration example in which a diffusion sheet is used instead of the reflective light guide 304 in the light source device of Display Device Example 3. Specifically, two optical sheets (in other words, diffusion sheets) that convert the diffusion characteristics in the vertical and horizontal directions of the drawing (front-to-back directions, not shown) are used on the light emission 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] The optical sheet may be a single sheet instead of a two-sheet configuration. In a single-sheet configuration, the vertical and horizontal diffusion characteristics are adjusted by the fine shapes of the front and back surfaces of the single optical sheet. Alternatively, multiple diffusion sheets may be used to share the functions. In the example of FIG. 10 , the reflection and diffusion characteristics due to the front and back shapes of optical sheets 207A and 207B can be optimally designed using the number of LEDs 201, the divergence angle from LED substrate 202, and the optical specifications of 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 of FIG. 10 , the diffusion characteristics are adjusted by the surface shapes of multiple diffusion sheets instead of light guides.

[0173] In the example of FIG. 10 , polarization conversion is performed in the same manner as in the display device example 3 described above. That is, in the example of FIG. 10 , the reflective polarizing plate 49 may be configured to have the property of reflecting S-polarized light (transmitting P-polarized light). In this case, the reflective polarizing plate 49 transmits P-polarized light from the light source LED 201, and the transmitted light enters the liquid crystal display panel 11. The reflective polarizing plate 49 reflects S-polarized light from the light source LED 201, and the reflected light passes through the retardation plate 270 shown in FIG. 10 . The light that passes through the retardation plate 270 is reflected by the reflector 271. The light reflected by the reflector 271 passes through the retardation plate 270 again and is converted to P-polarized light. The polarization-converted light passes through the reflective polarizing plate 49 and enters the liquid crystal display panel 11.

[0174] It should be noted that the λ / 4 plate 270, which is the retarder in FIG. 10, does not necessarily have to have a phase difference of λ / 4 with respect to polarized light that is perpendicularly incident on the λ / 4 plate 270. In the configuration of FIG. 10, any retarder that changes the phase by 90° (λ / 2) when polarized light passes through it twice may be used. The thickness of the retarder may be adjusted according to the distribution of incident angles of the polarized light. It should be noted that, in FIG. 10 as well, the polarization design for polarization conversion may be configured in reverse (reversing the S-polarized light and P-polarized light) from the above explanation.

[0175] In a typical TV device, the light emitted from the liquid crystal display panel 11 has similar diffusion characteristics in both the horizontal direction of the screen (shown by the X-axis in FIG. 12( a)) and the vertical direction of the screen (shown by the Y-axis in FIG. 12( b)). In contrast, the diffusion characteristics of the light beam emitted from the liquid crystal display panel 11 of this embodiment are, for example, as shown in Example 1 of FIG. 12 , when the viewing angle at which the luminance is 50% of that at a front view (0-degree angle) is set to 13 degrees, this is 1 / 5 of the 62-degree viewing angle of a typical TV device. Similarly, the vertical viewing angle is set asymmetrically between the top and bottom, and the reflection angle and the area of ​​the reflective surface of the reflective light guide are optimized to keep the upper viewing angle to about 1 / 3 of the lower viewing angle. As a result, the amount of image light directed toward the monitoring direction is significantly improved compared to conventional LCD TVs, with brightness being 50 times higher or more.

[0176] Furthermore, assuming the viewing angle characteristics shown in Example 2 of Figure 12, if the viewing angle at which brightness is 50% of that at a front view (angle of 0 degrees) is set to 5 degrees, this is 1 / 12 of the 62 degrees of devices used for general TV applications. Similarly, the vertical viewing angle is set equal at the top and bottom, and the reflection angle and area of ​​the reflective surface of the reflective light guide are optimized to keep the viewing angle to about 1 / 12 of that of devices used for general TV applications. As a result, the amount of image light directed in the monitoring direction is significantly improved compared to conventional LCD TVs, and brightness is more than 100 times higher.

[0177] As described above, by setting the viewing angle to a narrow angle, the amount of luminous flux directed in the monitoring direction can be concentrated, significantly improving the efficiency of light utilization. As a result, even when using a liquid crystal display panel for general TV applications, by controlling the light diffusion characteristics of the light source device, it is possible to achieve a significant improvement in brightness with similar power consumption, making it possible to create a video display device that is compatible with information display systems aimed at bright outdoor areas.

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

[0179] Similarly, when monitoring with a 15-inch panel in portrait orientation and a monitoring distance of 0.8 m, a convergence angle of 7 degrees will allow the image light from the four corners of the screen to be effectively directed towards the monitor. As described above, depending on the size of the liquid crystal display panel and whether it is used portrait or landscape, the overall brightness of the screen can be improved by directing the image light from the periphery of the screen towards the monitor who is in the optimum position to monitor the centre of the screen.

[0180] As shown in Figure 9, the basic configuration involves a light source device directing a light beam with a narrow angle of directionality to a liquid crystal display panel 11, which is then luminance-modulated according to a video signal. The video information displayed on the screen of the liquid crystal display panel 11 is then reflected by a retroreflector, and the resulting spatially floating image is displayed indoors or outdoors via a transparent member 100.

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

[0182] <Example of Image Display Processing in Space-Floating Image Display Device> Next, an example of a problem solved by the image processing of this embodiment will be described with reference to Fig. 13A. In the space-floating image display device 1000 (Fig. 3, Fig. 4A to Fig. 4P), when the far side of the space-floating image 3 from the user's perspective is inside the housing of the space-floating image display device 1000 and it is sufficiently dark, the user will visually recognize that the background of the space-floating image 3 is black.

[0183] Here, an example of displaying a character "panda" 1525 in a floating-in-space image 3 will be described with reference to Fig. 13A. First, for an image including a pixel region for drawing the image of the character "panda" 1525 and a transparent information region 1520 that is a background image, as shown in Fig. 13A(1), the image control unit 1160 in Fig. 3 distinguishes and recognizes the pixel region for drawing the image of the character "panda" 1525 from the transparent information region 1520 that is a background image.

[0184] A method for distinguishing and recognizing the character image from the background image is, for example, to configure the image processing of the video control unit 1160 so that the background image layer and the layer of the character image in front of the background image layer can be processed as separate layers, and the character image and background image can be distinguished and recognized based on the superimposition relationship when these layers are combined.

[0185] Here, the image control unit 1160 recognizes black pixels that depict objects such as character images and transparent information pixels as different information. However, it is assumed that both the black pixels that depict objects and the transparent information pixels have a luminance of 0. In this case, when the Space Floating Image 3 is displayed, there is no difference in luminance between the pixels that depict black in the image of the character "panda" 1525 and the pixels of the transparent information region 1520, which is the background image. Therefore, in the Space Floating Image 3, as shown in FIG. 13A (2), neither the pixels that depict black in the image of the character "panda" 1525 nor the pixels of the transparent information region 1520 have luminance, and they are visually perceived by the user as the same optically black space. In other words, the black portions of the image of the character "panda" 1525, which is an object, blend into the background, and only the non-black portions of the character "panda" 1525 are perceived as floating in the display region of the Space Floating Image 3.

[0186] An example of image processing according to this embodiment will be described with reference to FIG. 13B. FIG. 13B is a diagram illustrating an example of image processing that more effectively resolves the issue of the black image region of the object blending into the background, as described in FIG. 13A. In FIGS. 13B(1) and 13B(2), the upper side shows the display state of the floating-in-space image 3, and the lower side shows the input / output characteristics of the image processing of the image of the object. Note that the image of the object (character "panda" 1525) and the corresponding data may be read from the storage unit 1170 or memory 1109 in FIG. 3, or may be input from the video signal input unit 1131, or may be acquired via the communication unit 1132.

[0187] In the state shown in Figure 13B(1), the input / output characteristics of the image processing of the object image are in a linear state with no particular adjustment. In this case, the display state is the same as in Figure 13A(2), and the black image area of ​​the object blends into the background. In contrast, in Figure 13B(2), the video control unit 1160 of this embodiment adjusts the input / output characteristics of the image processing of the image of the object (character "panda" 1525) to the input / output characteristics shown in the lower row.

[0188] That is, the video control unit 1160 performs image processing with input / output characteristics on the image of the object (character "panda" 1525), which has a characteristic of converting pixels in low-brightness areas of the input image into output pixels with increased brightness values. After the image of the object (character "panda" 1525) has been subjected to the image processing with input / output characteristics, a video including the image of the object (character "panda" 1525) is input to the display device 1 and displayed. Then, as shown in the upper part of FIG. 13B (2), the display state of the floating in space image 3 is such that the brightness of pixel areas depicting black in the image of the character "panda" 1525 increases. This allows the user to distinguish the areas depicting black among the areas depicting the image of the character "panda" 1525 without them blending into the black background, making it possible to display the object more appropriately.

[0189] 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 space-floating image display device 1000 through the window, improving the visibility of the object. Therefore, for example, even if the object includes pixels with a brightness value of 0 among the pixels constituting the object before the image processing (i.e., at the time when the image of the object and the corresponding data are read from the storage unit 1170 or memory 1109 in FIG. 3, or at the time when the image of the object is input from the video signal input unit 1131, or at the time 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 the object into an object with increased brightness values ​​of pixels in low-brightness areas, and then the object is displayed on the display device 1 and converted into a space-floating image 3 by the optical system of the space-floating image display device 1000.

[0190] That is, the pixels that make up the object after image processing of the input / output characteristics are converted to a state in which they do not include pixels with a brightness value of 0, and then they are displayed on the display device 1 and converted into a floating image 3 by the optical system of the floating image display device 1000.

[0191] In the image processing of Figure 13B(2), a method for applying image processing with the input / output characteristics of Figure 13B(2) only to the image area of ​​the object (character "panda" 1525) is, for example, to configure the image processing of the video control unit 1160 so that the background image layer and the layer of the character image in front of the background image layer can be processed as separate layers, and the image processing with the input / output characteristics of Figure 13B(2) is applied to the character image layer while not applying this image processing to the background image layer.

[0192] Then, by combining these layers, image processing with a characteristic of raising the low-brightness areas of the input image is performed only on the character image, as shown in Fig. 13B (2). Alternatively, after the character image layer and background image layer are combined, image processing with the input / output characteristics of Fig. 13B (2) may be performed only on the character image area.

[0193] Furthermore, the input / output image characteristics used in the image processing for enhancing low-luminance regions of the input / output characteristics for the input image are not limited to the example shown in FIG. 13B(2). Any image processing for enhancing low luminance may be used, including so-called brightness adjustment. Alternatively, image processing for improving visibility by controlling the gain that changes the weighting of Retinex processing, as disclosed in International Publication WO 2014 / 162533, may be performed.

[0194] According to the image processing of FIG. 13B(2) described above, it is possible to make the user aware of areas where black is drawn among areas where images of characters, objects, etc. are drawn without blending into the black background, thereby realizing a more suitable display.

[0195] 13A and 13B, the problems and more suitable image processing were explained using examples of a space-floating image display device in which the background appears black (for example, the space-floating image display device 1000 in FIGS. 4A to 4G, or the space-floating image display device 1000 in a state in which the rear side window is shaded in FIGS. 4I and 4J). However, this image processing is also effective for devices other than these space-floating image display devices.

[0196] Specifically, in the space-floating image display device 1000 of Fig. 4H and the space-floating image display device 1000 in Fig. 4I and Fig. 4J where the rear window is not shaded, the background of the space-floating image 3 is not black, but the scenery behind the space-floating image display device 1000 through the window. In this case, the problems explained in Fig. 13A and Fig. 13B also exist.

[0197] That is, the part of the image of the character "panda" 1525, which is an object, that is drawn in black will blend into the scenery behind the space-floating image display device 1000 through the window. In this case, by using the image processing of Fig. 13B (2), the part of the image of the character "panda" 1525, which is an object, that is drawn in black will be recognized as being distinct from the scenery behind the space-floating image display device 1000 through the window, improving the visibility of the object.

[0198] That is, by using the image processing of FIG. 13B(2), the area displaying the image of the character "panda" 1525, which is an object, can be recognized as distinct from the scenery behind the space floating image display device 1000 through the window, and it can be more easily recognized that the character "panda" 1525, which is the object, is in front of the scenery, improving the visibility of the object.

[0199] 4K, 4L, and 4M, as described above, when another image (such as an image from the transmissive self-luminous image display device 1650 or an image from the second display device 1680) is displayed at a position different in depth from the space-floating image 3, the background of the space-floating image 3 is not black, but the other image. In this case, the problems described in FIGS. 13A and 13B also exist.

[0200] That is, the part of the image of the character "panda" 1525, which is an object, that is drawn in black will blend into the other image that is displayed at a different depth from the floating image in space 3. In this case as well, by using the image processing of Fig. 13B(2), the part of the image of the character "panda" 1525, which is an object, that is drawn in black will be recognizable as being distinct from the other image, improving the visibility of the object.

[0201] In other words, by using the image processing of Figure 13B (2), the area displaying the image of the object character "panda" 1525 can be recognized as distinct from the other image, and it can be more easily recognized that the object character "panda" 1525 is in front of the other image, improving the visibility of the object.

[0202] An example of the image display process of this embodiment will be described with reference to Fig. 13C. Fig. 13C shows an example of the image display process of this embodiment, in which the space floating image 3 and a second image 2050, which is another image, are simultaneously displayed. The second image 2050 may correspond to the image displayed by the transmissive self-luminous image display device 1650 of Fig. 4K or 4L. The second image 2050 may also correspond to the image displayed by the second display device 1680 of Fig. 4M.

[0203] That is, the example of the image display in Fig. 13C shows a specific example of the image display examples of the space-floating image display device 1000 in Figs. 4K, 4L, and 4M. In the example of this figure, a bear character is displayed in space-floating image 3. Areas other than the bear character in space-floating image 3 are displayed in black, and become transparent as a space-floating image. In addition, the second image 2050 is a background image in which a plain, a mountain, and a sun are drawn.

[0204] 13C , the floating-in-space image 3 and the second image 2050 are displayed at different depth positions. When the user 230 views the two images, the floating-in-space image 3 and the second image 2050, in the line of sight of the arrow 2040, the user 230 can view the two images superimposed on each other. Specifically, the bear character of the floating-in-space 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 space floating image 3 is formed as a real image in the air, when the user 230 moves their viewpoint slightly, they can recognize the depth of the space floating image 3 and the second image 2050 due to parallax. Therefore, the user 230 can get a stronger sense of floating in space from the space floating image 3 while viewing the two images in an overlapping state.

[0206] An example of the image display process of this embodiment will be described with reference to Fig. 13D. Fig. 13D(1) is a diagram of the floating in space image 3, from the example of image display of this embodiment in Fig. 13C, as seen from the line of sight of the user 230. Here, a bear character is displayed in the floating in space image 3. The area other than the bear character in the floating in space image 3 is displayed in black, and the floating in space image is transparent.

[0207] 13D(2) is a diagram showing the second image 2050 in the example of the video display of this embodiment shown in FIG. 13C as viewed from the line of sight of the user 230. In the example shown in this figure, the second image 2050 is a background image in which a plain, a mountain, and a sun are depicted.

[0208] 13D(3) is a diagram showing the state in which the second image 2050 and the floating in space image 3 appear superimposed in the line of sight of the user 230, among the example of image display of this embodiment in Fig. 13C. Specifically, the bear character of the floating in space image 3 appears superimposed in front of the background of plains, mountains, and the sun depicted in the second image 2050.

[0209] Here, when the space-floating image 3 and the second image 2050 are displayed simultaneously, it is desirable to pay attention to the balance of brightness between the two images in order to more favorably ensure the visibility of the space-floating image 3. If the second image 2050 is too bright compared to the brightness of the space-floating image 3, the displayed image of the space-floating image 3 will be transparent, and the second image 2050, which is the background, will be strongly visible through it.

[0210] Therefore, the output of the light source of the spatially floating image 3 and the display image brightness of the display device 1, and the output of the light source of the display device displaying the second image 2050 and the display image brightness of the display device should be set so that at least the brightness per unit area of ​​the spatially floating image 3 at the display position of the spatially floating image 3 is greater than the brightness per unit area of ​​the image light that reaches the display position of the spatially floating image 3 from the second image 2050.

[0211] Note that, since this condition only needs to be satisfied when the space-floating image 3 and the second image 2050 are displayed simultaneously, when switching from the first display mode in which the space-floating image 3 is not displayed and only the second image 2050 is displayed to the second display mode in which the space-floating image 3 and the second image 2050 are displayed 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 may be realized by the control unit 1110 in Fig. 3 controlling the display device 1 and the display device that displays the second image 2050 (the transmissive self-luminous image display device 1650 in Fig. 4K or 4L or the second display device 1680 in Fig. 4M).

[0212] Note that when switching from the above-described first display mode to the above-described second display mode, if control is performed to reduce the brightness of second image 2050, the brightness may be reduced uniformly across the entire screen of second image 2050. Alternatively, instead of reducing the brightness uniformly across the entire screen of second image 2050, the brightness reduction effect may be greatest in the portion where an object is displayed in space-floating image 3, and the brightness reduction effect may be gradually weakened around that portion. In other words, the visibility of space-floating image 3 can be sufficiently ensured by reducing the brightness of second image 2050 only in the portion where space-floating image 3 is visually recognized as being superimposed on second image 2050.

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

[0214] In addition, in the space floating image display device 1000 where the position of the object displayed in the space floating image 3 is approximately at the center of the space floating image 3, the position where the brightness reduction effect of the gradation processing of the brightness reduction effect is greatest can be set to the center position of the space floating image 3.

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

[0216] Note that when displaying the space-floating image 3, control may be performed so as not to display the second image 2050. Since the visibility of the space-floating image 3 is improved when the second image 2050 is not displayed, this control is suitable for the space-floating image display device 1000 and the like, which are used in applications where the user must be able to reliably view the space-floating image 3 when the space-floating image 3 is displayed.

[0217] <Example 2> As Example 2 of the present invention, an example of another configuration example of a space-floating image display device will be described. Note that the space-floating image display device according to this example is obtained by changing the optical system stored in the space-floating image display device described in Example 1 to the optical system shown in Fig. 14(1) or Fig. 14(2). In this example, differences from Example 1 will be described, and repeated explanations of the same configuration as Example 1 will be omitted. Note that in the following description of this example, the predetermined polarized light and the other polarized light are polarized waves whose phases differ by 90° from each other.

[0218] Fig. 14(1) shows an example of an optical system and optical path according to this embodiment. The optical system shown in Fig. 14(1) is configured such that the display device 1 is closer to the polarization separation member 101B in the optical system of Fig. 2C, making the entire optical system more compact. In Fig. 14(1), components that are assigned the same reference numerals as those in Fig. 2C will not be described in detail again.

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

[0220] Therefore, image light of a predetermined polarization (P-polarized light in the figure) traveling in the vertical direction 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 passed through the λ / 4 plate 21 twice, and is converted from the predetermined polarization (P-polarized light in the figure) at the time of emission from the display device 1 to the other polarization (S-polarized light in the figure). The image light that travels again toward the polarization separation member 101B is the other polarization (S-polarized light in the figure), and is therefore reflected by the polarization separation member 101B toward the position where the user should be. The traveling direction of the image reflected by the polarization separation member 101B is determined based on the angle at which the polarization separation member 101B is disposed.

[0221] In the example of 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 in space. The floating image 3A can be viewed by the user from the direction of arrow A.

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

[0223] In the example of FIG. 14(1), the display device 1, the polarization separating member 101B, and the retroreflector 2 are arranged closer than in the example of FIG. 2C. This allows the entire optical system to be configured more compactly. However, the amount by which the space-floating image 3A protrudes from the optical system of FIG. 14(1) is not very large. For example, as an indicator of the amount by which the space-floating image 3A protrudes from the optical system, the distance (L1 in the example of FIG. 14(1)) from the position where the central light beam of the image light is reflected by the polarization separating member 101B to the position where the image light forms the space-floating image 3A is shown in the figure.

[0224] 14(1), the characteristics of P-polarized light and S-polarized light may be interchanged. Specifically, the predetermined polarization of the image light emitted from the display device 1 may be S-polarized light, and the characteristics of P-polarized light and S-polarized light may be interchanged with respect to the reflection characteristics of the polarization separation member 101B. In this case, the P-polarized light and S-polarized light shown in the figure are both reversed, but the optical design, such as the optical path, can be realized in exactly the same way.

[0225] Next, Fig. 14(2) shows another example of an optical system and an optical path according to this embodiment. The optical system of Fig. 14(2) is a modified version of the optical system of Fig. 14(1) in order to increase the amount of the floating image projecting from the optical system while realizing the same compactness as the optical system of Fig. 14(1). In Fig. 14(2), detailed descriptions of components with the same reference numerals as Fig. 14(1) will be omitted.

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

[0227] 14(1), the image light passing through the polarization separation member 101B is not faced with the retroreflector 2 having the λ / 4 plate 21 attached thereto, but with the specular reflector 4 having the λ / 4 plate 21B attached thereto. Here, the reflection at the specular reflector 4 is specular reflection (also called regular reflection), not retroreflection.

[0228] Therefore, the image light that has passed through polarization separation member 101B is specularly reflected by specular reflector 4 to which λ / 4 plate 21B is attached. The image light that has been specularly reflected by specular reflector 4 and travels again toward polarization separation member 101B has been converted from the predetermined polarization (P-polarized in the figure) at the time of emission from display device 1 to the other polarization (S-polarized in the figure) by having passed through λ / 4 plate 21 twice. The image light that has traveled again toward polarization separation member 101B is the other polarization (S-polarized in the figure), and is therefore reflected by polarization separation member 101B.

[0229] Here, because the orientation of the polarization separation member 101B in Figure 14(2) is different from that in Figure 14(1), the image light reflected by the polarization separation member 101B travels in the opposite direction from the position where the user should be. A retroreflector 2 with a λ / 4 plate 21C attached is disposed at the destination of the image light reflected by the polarization separation member 101B. The image light is retroreflected by the retroreflector 2. The image light that is retroreflected by the retroreflector 2 and travels again toward the polarization separation member 101B has been converted from the other polarized light (S-polarized light in the figure) to the specified polarized light (P-polarized light in the figure) by passing through the λ / 4 plate 21C twice.

[0230] The image light that travels back toward the polarization separation member 101B is of a predetermined polarization (P polarization in the figure), so it passes through the polarization separation member 101B and continues toward the location where the user should be. The image light that has passed through the polarization separation member 101B forms a floating image 3B in space. The floating image 3B can be easily viewed by the user from the direction of arrow A.

[0231] 14(2), as in Fig. 14(1), due to the characteristics of retroreflection by the retroreflector 2, the optical path length of the image light emitted from the display device 1 to reach the retroreflector 2 is equal to the optical path length of the image light emitted from the retroreflector 2 to reach the formation position of the space floating image 3B. This relationship determines the formation position of the space floating image 3B in the traveling direction of the image light transmitted through the polarization separation member 101B.

[0232] 14(2), the optical path length of the image light emitted from the display device 1 to reach the retroreflector 2 is longer than the optical path length of the image light emitted from the display device 1 to reach the retroreflector 2 in FIG. 14(1). This is because in the optical system of FIG. 14(2), an optical path going back and forth 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 of the image light emitted from the display device 1 to reach the retroreflector 2.

[0233] As a result, in the optical system of Figure 14(2), the distance from the position where the central ray of the image light passes through the polarization separation member 101B to the position where the image light forms the space-floating image 3B (L2 in the example of Figure 14(2)) is significantly longer than the distance from the position where the central ray of the image light is reflected by the polarization separation member 101B to the position where the image light forms the space-floating image 3A (L1 in the example of Figure 14(1)) in the optical system of Figure 14(1).

[0234] 14(2), the characteristics of P-polarized light and S-polarized light may be interchanged. Specifically, the predetermined polarization of the image light emitted from the display device 1 may be S-polarized light, and the characteristics of P-polarized light and S-polarized light may be interchanged with respect to the reflection characteristics of the polarization separation member 101B. In this case, the P-polarized light and S-polarized light shown in the figure are both reversed, but the optical design, such as the optical path, can be realized in exactly the same way.

[0235] As described above, according to the optical systems of Fig. 14(1) and Fig. 14(2) in the second embodiment of the present invention, a more compact optical system can be realized. In particular, according to the optical system of Fig. 14(2), it is possible to increase the amount of the floating image projecting from the optical system, despite the more compact optical system.

[0236] In addition, when the optical system of Fig. 14(1) or Fig. 14(2) is incorporated into a space-floating image display device, it can be realized by replacing the optical system in the space-floating image display device described in Example 1 with the optical system of Fig. 14(1) or Fig. 14(2). Specifically, the optical system of Fig. 14(1) may be replaced with the optical system of the space-floating image display device of Fig. 4E, Fig. 4F, Fig. 4G, Fig. 4H, Fig. 4I, Fig. 4J, Fig. 4K, Fig. 4L, or Fig. 4M. In this case, since the optical system becomes compact, it is possible to make the housing of the space-floating image display device of each figure smaller.

[0237] Specifically, the optical system of Fig. 14(2) may be replaced with the optical system of the space-floating image display device of Fig. 4E, Fig. 4F, Fig. 4G, Fig. 4K, or Fig. 4L. In this case, it is possible to increase the amount of the space-floating image projecting from the optical system. Also, since the optical system becomes compact, it is possible to make the housing of the space-floating image display device of each figure smaller.

[0238] <Embodiment 3> As embodiment 3 of the present invention, an example of the configuration of a space floating image display device will be described. The space floating image display device according to this embodiment can similarly apply the configurations of the respective drawings explained in embodiment 1 and embodiment 2 as a basic configuration. In this embodiment, differences from embodiments 1 and 2 will be mainly explained, and repeated explanations of the same configurations as embodiments 1 and 2 will be omitted.

[0239] Comparative Example 1 FIG. 15 shows an example of the configuration of an optical system and other components of a comparative example to Example 3. This configuration example is based on the configuration of the optical system shown in FIG. 2D described above. Here, the two orthogonal directions constituting a horizontal plane are the X and Y directions, and the vertical direction is the Z direction. This comparative example includes an optical plate 150 and a display device 1. In other words, the display device 1 is an image display unit. The display device 1 includes a light source device 13 that generates light and a liquid crystal display panel 11 that is a display element that displays an image based on the light. The optical plate 150 includes a transparent member 100 such as glass and a retroreflector (in other words, a retroreflective member) 5 provided on the underside of the transparent member 100. The optical plate 150 is disposed on a horizontal plane. The display device 1 is disposed diagonally below the optical plate 150. The display device 1 is disposed with the image light exit surface (in other words, the display surface) of the liquid crystal display panel 11 tilted obliquely. In the image light a1 emitted from the image light emission surface of the display device 1, the main ray 9020A is indicated by a solid arrow, and the upper and lower ends of the light flux of the image light are indicated by dashed lines.

[0240] A chief ray 9020A, which represents a light beam in 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. The incident angle α here is the angle with respect to the normal direction of the plane of the retroreflector 5. The angle of incidence of the chief ray 9020A with respect to the plane of the retroreflector 5 is αA = 90 degrees - α = 25 degrees.

[0241] In Example 3 and onward, the incident angle and the exit angle are defined as angles relative to the normal direction of the incident surface, such as the angle α. Since it depends on the definition, the gist remains the same even if the incident angle and the exit angle are defined as angles relative to the incident surface.

[0242] Due to the action of the retroreflector 5, the chief ray 9020A passes through the transparent member 100 and travels in the Z direction, while being retroreflected in the X and Y directions. As a result, a reflected light ray 9021A, which represents the light beam in the retroreflected image light a2, passes through the transparent member 100, and then travels along an optical path that is mirror-symmetrical with respect to the chief ray 9020A with respect to the retroreflector 5, in a direction away from the retroreflector 5, and forms a space-floating image 3 (in other words, a standing image 3A) as a real image on the imaging plane. The emission angle of the reflected light 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] 2D, as shown in Fig. 15, consider obtaining a floating image 3 (image 3A) having a tilt of 65 degrees with respect to a horizontal plane and an optical plate 150 including a retroreflector 5. The tilt angle (in other words, the image angle) of the floating image 3 (image 3A) with respect to the horizontal plane is set to B = 65 degrees.

[0244] To achieve this, the display device 1 is tilted downward relative to the optical plate 150 including the retroreflector 5, at an angle of 65 degrees, the same as the above-mentioned tilt angle B. As a result, the chief ray 9020A, which represents the light beam of the image light a1 emitted from the image light emission surface of the display device 1 in the direction perpendicular to the surface at an angle of 90 degrees, has an incident angle α of 65 degrees on the retroreflector 5. Correspondingly, the emission angle of the retroreflected light is 65 degrees. As a result, an image 3A having a tilt angle B = 65 degrees is formed.

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

[0246] As described above, in the case of an optical system such as that shown in FIG. 2D , the angle of incidence of the light beam emitted from the display device 1 onto the retroreflector 5 (in FIG. 2D , this is the angle relative to the plane of the retroreflector 5, but it can also be considered as the angle relative to the normal direction of the retroreflector 5) is used to be around 45 degrees. This is because, based on the device characteristics of the retroreflector 5 and optical principles, when the angle of incidence is 45 degrees, the reflection efficiency of the incident image light on the retroreflector 5 is the highest, and the peak brightness when observing the floating image 3 in space is the best. 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 incident image light is highest. Specifically, there is a deviation of 65 degrees - 45 degrees = 20 degrees. Therefore, the luminance peak A1 of the image 3A generated in this comparative example is lower than in the case of 45 degrees in FIG. 2D .

[0248] Furthermore, in this comparative example, with an incident angle α = 65 degrees and a corresponding angle αA = 25 degrees, in order to display the entire image emitted from the display device 1 on the screen of the space floating image 3, an optical plate 150 including a retroreflector 5 longer than the length of the image light exit 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 length 1591. As a result, in order to obtain a space floating image 3 with a sufficiently large screen, the space floating image display device must be large. In particular, the length of the optical plate 150 in the depth direction must be large.

[0249] [Comparative Example 2] In contrast, in order to prevent the size of the space floating image display device from increasing, it is necessary to use an optical plate 150 including a relatively short retroreflector 5, as shown in the comparative example of Figure 16. The comparative example of Figure 16 shows that while the basic configuration is the same as that of Figure 15, the length of the optical plate 150 in the depth direction (Y direction) is suppressed and limited, and the size of the screen (in other words, the display range) of the space floating image 3 is narrowed in the vertical direction. In the comparative example of Figure 16, the optical plate 150 has a length of 1592 when there is a restriction that the length in the depth direction (Y direction) cannot be made too long.

[0250] However, in the comparative example of FIG. 16 , the length 1592 of the optical plate 150 does not cover part of the range of the luminous flux of the image light from the display surface of the display device 1. Specifically, a light ray 9023A emitted from the lower end (point p1) of the image light emission surface of the display device 1 reaches a point 9024A in the horizontal plane corresponding to the optical plate 150 where no retroreflector 5 is present, and is not retroreflected, so no floating image corresponding to this light ray 9023A is generated. In this comparative example, a light ray 9024A emitted from approximately the center position (point p3) of the image light emission surface of the display device 1 travels to an end (point Q) of the retroreflector 5 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 from this end (point Q) away from the retroreflector 5 is the upper end (point q2) of the standing image 3Ab.

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

[0252] Even if one wants to realize a figurine 3A with an inclination angle of 65 degrees as in the above comparative example, there is a limit to the depth length of the optical plate 150 depending on the use and implementation of the space floating image display device 1000. When miniaturization is realized by suppressing the length of the optical plate 150, the screen size of the figurine 3A becomes small as in the comparative example of Fig. 16 .

[0253] [Optical System of the Space-Floating Image Display Device of Example 3] Fig. 17 shows an example of the configuration of the optical system, which is the main part of the space-floating image display device 1000 of Example 3. Example 3 realizes a space-floating image 3 as a figurine 3A that is highly bright and easy to see. This figurine 3A is formed as a planar floating image standing at an angle closer to vertical than horizontal by being tilted at an angle of, for example, 65 degrees with respect to the optical plate 150 that is placed on a horizontal plane. Corresponding to the tilt angle B of the figurine 3A = 65 degrees, the angle that the figurine 3A makes with respect to the vertical direction is 25 degrees (90 degrees - 65 degrees = 25 degrees).

[0254] The optical system shown in Figure 17 is configured as an optical system suitable for a viewer to observe the image 3A, which is a floating image 3, from a relatively high angle diagonally above, that is, at an observation angle (depression angle) θB in Figure 17, which is deeper than the observation angle (depression angle) θA of the comparative example. In the example of Figure 17, θB = 45 degrees. In other words, in this embodiment 3, the optical system is configured so that when a 65-degree floating image 3A is observed at a 45-degree depression angle, it can be viewed as a suitable floating image 3 in space with a luminance peak B1. Specifically, the display device 1 and the floating image 3 are arranged in mirror symmetry at 65 degrees with respect to the optical plate 150 arranged on a horizontal plane, and a prism sheet 300 is provided on the surface of the display device 1 so that the angle of incidence α and the angle of emergence α of the image light relative to the retroreflector 5 are 45 degrees.

[0255] 17, in Example 3, similar to the comparative example in Fig. 15, a display device 1 including a liquid crystal display panel 11 is disposed at an inclination angle of 65 degrees relative to an optical plate 150 including a retroreflector 5. Then, image light from the display surface of the liquid crystal display panel 11, which serves as the image light exit surface, is made 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 a prism sheet 300 provided on the surface of the liquid crystal display panel 11 is used.

[0256] FIG. 17 differs significantly from the comparative example of FIG. 15 in that a prism sheet 300 realizing a predetermined refraction angle (C) is disposed adjacent to the image light exit 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 disposed adjacent 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 prism sheet 300 refracts image light emitted from the liquid crystal display panel 11 in a direction perpendicular to the display surface from the angle βA=90 degrees in FIG. 15 (the direction of the light ray 9020A in FIG. 17 ) to a desired angle βB=70 degrees (the image light exit angle corresponding to the desired incident angle). That is, in this example, the refraction angle C of the prism sheet 300 is 20 degrees. An example configuration of the prism sheet 300 will be described later.

[0257] In this Example 3, a chief ray 9020B representing a light beam of image light b1 emitted in the surface-normal direction from the display surface of the liquid crystal display panel 11 of the display device 1 is refracted by the refraction action of the prism sheet 300 at an angle C=20 degrees with respect to the surface-normal direction of the display surface as it travels toward the retroreflector 5, and becomes a ray at an angle βB=70 degrees with respect to the display surface, traveling toward the retroreflector 5. The dashed ray corresponds to the ray 9020A that is emitted in the surface-normal direction and travels toward the aforementioned point P in the absence of refraction. As a result, the chief ray 9020B of image light b1 has an incident angle α of 45 degrees on the retroreflector 5 (point Pb), and correspondingly, an angle αB with respect to the plane of the retroreflector 5 is 45 degrees.

[0258] As described above, for an optical system such as that shown in FIG. 2D , the reflection efficiency of the incident image light at the retroreflector 5 is highest when the incident angle is 45 degrees, resulting in a luminance peak due to the retroreflected light. In this Example 3 ( FIG. 17 ), the incident angle α is 45 degrees, and the corresponding angle αB is 45 degrees, so the retroreflected light is emitted at an exit angle α = 45 degrees and a corresponding angle αB = 45 degrees. The luminance peak B1 of the image 3A, which is the space-floating image 3 generated by the chief ray 9021B of the retroreflected image light b2, is highest when observed at a depression angle of 45 degrees, which is the observation angle θB corresponding to the observation direction BU from the user's viewpoint position 232. Therefore, in this Example 3 ( FIG. 17 ), the problem of the reduction in luminance peak A1 of the 65-degree image 3A as seen in the comparative example of FIG. 15 is improved, and the user, who is the observer, can easily view the 65-degree image 3A, which is particularly well-viewed when observed at a depression angle θB = 45 degrees.

[0259] Furthermore, in this embodiment 3 (FIG. 17), the length 1593 of the retroreflector 5 can be made shorter than the length 1591 in FIG. 15, and the entire image emitted from the display device 1 can be formed and displayed as a space-floating image 3. For comparison, points P and Pb are shown, and the point at which the chief ray from the center (point p0) of the image light emission surface of the display device 1 is incident on the plane of the optical plate 150 has changed from point P to point Pb. Therefore, compared to FIG. 15, the configuration of FIG. 17 shortens the length of the optical plate 150, thereby realizing a smaller space-floating image display device 1000, in other words, preventing it from becoming too large. Furthermore, when viewed from the front of the space-floating image 3, that is, from a user with an observation direction BU at a depression angle of 45 degrees, the configuration of FIG. 17 allows viewing at the luminance peak B1, and the vertical viewing range is improved compared to FIG. 16, allowing the entire screen of a sufficiently large size to be viewed.

[0260] [Angle Range] In this Example 3, the inclination angle B of the floating image 3 in space will be described based on 65 degrees. Of course, this inclination angle B is not limited to 65 degrees. It may be any angle selected within the angle range of 65 degrees ±X. This angle range is 55 degrees to 75 degrees when X is 10 degrees. More preferably, it is 60 degrees to 70 degrees when X is 5 degrees. In principle, this inclination angle B can also be set to an angle within the range of 75 degrees to 90 degrees as an upper limit. In this Example 3, the inventors conducted experiments to examine the inclination angle B that best suits the appearance of the character image in the statue 3A for multiple users, and selected 65 degrees as the inclination angle B. In this examination, a depression angle of 45 degrees was assumed as the standard observation direction and observation angle when observing the character image in the statue 3A at inclination angle B from the user's viewpoint, and the appearance at various inclination angles B was compared. Then, when viewing the character image at that depression angle, an inclination angle B was selected that makes it easy to see / feel the character standing on a horizontal plane.

[0261] When the above-mentioned condition for the tilt angle B is converted into the condition for the refraction angle C of the prism sheet 300, the range of the refraction angle C may be any angle selected from within an angle range of 20 degrees ±Y, with 20 degrees as the base. This angle range is from 10 degrees to 30 degrees, assuming Y is 10 degrees. More preferably, it is from 15 degrees to 25 degrees, assuming Y is 5 degrees.

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

[0263] The prism sheet 300 is an optical element that refracts light. In other words, the prism sheet 300 may be referred to as a linear prism sheet, a prism plate, a light guide, a light guide element, a light beam direction change element, a light beam direction change sheet, a light beam direction conversion element, or the like. A well-known example of a prism sheet implementation is the DTF series by Optical Solutions Co., Ltd., which uses a microprism array. This product can be used as the prism sheet 300 in this embodiment.

[0264] 17, in order to allow the image light (light ray 9020B1) emitted in the direction perpendicular to the display surface 1801 of the liquid crystal display panel 11 to be incident on the retroreflector 5 at an angle α=45 degrees, a prism sheet 300 as shown in Fig. 18 is disposed (for example, glued) close 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 (light ray 9020B1) into image light (light ray 9020B) refracted in a predetermined direction (the direction of angle βB).

[0265] In the configuration example of Figure 18, the prism sheet 300 is arranged on the top surface of the liquid crystal display panel 11, but depending on the implementation, if another component is present on the top surface of the liquid crystal display panel 11, the prism sheet 300 may be arranged on the surface of that other component.

[0266] As shown in FIG. 18 , a prism sheet 300 has a surface facing the display surface of the liquid crystal display panel 11 (the lower side in the z-axis direction, the side closest to the display surface 1801) with a concave-convex portion 301. The surface of the prism sheet 300 having the concave-convex portion 301 faces the display surface 1801 of the liquid crystal display panel 11. In Example 3 ( FIG. 18 ), the concave-convex portion 301 includes multiple zigzag-shaped or mountain-shaped grooves 303 (i.e., recesses) having at least inclined portions 302, which are repeatedly formed in the y direction, which is an in-plane direction. The inclination of the inclined portions 302 is oblique to the y direction and the z direction. In other words, multiple mountains 312 (i.e., convex portions) having inclined portions 302 are repeatedly formed in the y direction. In other words, the shape of the concave-convex 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 passes through prism sheet 300 having such a shape, refraction of the light occurs, and when light (ray 9020B1) is incident on inclined portions 302 of grooves 303 / peaks 312, light (ray 9020B) is refracted at a constant refraction angle C = 20 degrees and emitted. In the illustrated example, light emitted from display surface 1801, for example, ray 9020B1, enters peaks 312 from the side where grooves 303 are located in prism sheet 300, is refracted at refraction angle C (20 degrees) with respect to the normal to display surface 1801, and is emitted as ray 9020B from the back surface (upper side in the z-axis direction) of prism sheet 300 at an angle βB (70 degrees) with respect to the normal to display surface 1801.

[0268] In Example 3, a light ray 9020B1 that enters the liquid crystal display panel 11 in a direction perpendicular to the display surface 1801 is refracted by the prism sheet 300 at a refraction angle C (20 degrees) and then exits at an angle βB (70 degrees), thereby setting the angle of incidence α on the retroreflector 5 to 45 degrees. Therefore, the prism sheet 300 uses a device having a refractive index corresponding to a refraction angle C = 20 degrees. Note that, since FIG. 18 focuses on the relationship between the incident light and the exiting light of the prism sheet 300, detailed illustrations of the behavior of light refraction and other aspects within the prism sheet 300 are omitted.

[0269] [Space-Floating Image Display Device of Example 3: Housing] FIG. 19 shows a cross-sectional view (Y-Z plane view) of a configuration example of a space-floating image display device 1000 of Example 3, which is configured including basic components such as the optical system of FIG. 17 . A display device 1B with a prism sheet 300 and a control board (in other words, a control device) 350 are housed and installed within a housing 1190 of the space-floating image display device 1000. An optical plate 150 is installed on the top surface of the housing 1190 so that it forms a horizontal plane (X-Y plane). The three-dimensional shape of the housing 1190 is not limited, and may be, for example, box-shaped or cylindrical, as described below. The control board 350 is a system circuit on which components such as the control unit 1110 shown in FIG. 21 are mounted. 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 also be housed within the housing 1190 as needed.

[0270] A housing 1190 as shown in Fig. 19 is installed in a user's environment. The housing 1190 in Fig. 19 is a horizontally placed housing 1190 with a horizontal upper surface, and the figure 3A is formed at an angle B = 65 degrees with respect to the horizontal plane. The user observes and visually recognizes the figure 3A from a viewpoint position 232 at an observation angle θB, i.e., a downward diagonal depression angle of, for example, 45 degrees.

[0271] 19 also illustrates an example in which the camera 1180A of the imaging unit 1180 in FIG. 3, the aerial operation detection sensor 1351, the microphone 1139A for audio input, and the speaker 1140A for audio output are provided. These components are also connected to the control board 350. The optical axis of the camera 1180A faces, for example, the floating-in-space image 3 and the user, and can capture images of the state of the aerial operation performed by the fingers 235 on the floating-in-space image 3, as well as the user's face. The optical axis of the aerial operation detection sensor 1351 covers, for example, the plane of the floating-in-space image 3, and can detect the state of the aerial operation performed by the fingers 235 on the floating-in-space image 3.

[0272] Although the prism sheet 300 has been described as a part of the display device 1B, the prism sheet 300 may be regarded as a component of the optical system. The prism sheet 300 may be disposed on the optical path between the display device 1 and the retroreflector 5.

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

[0274] The top surface of the housing 1190D has an opening, in other words, a transmission portion, that corresponds to the transparent member 100 of the optical plate 150. The shape of the opening / transmission portion is circular in this example, but is not particularly limited and may be rectangular or the like. Since the figurine 3A is placed higher on the top surface of the housing 1190D, it functions as a floor / stage for the figurine 3A.

[0275] The figurine 3A, which is the floating image 3 in space, is formed at a predetermined inclination angle B of 65 degrees above the horizontal plane (X-Y plane) corresponding to the top surface of the housing 1190D. In this example, the screen that is the display range 3R of the figurine 3A is a portrait screen, but is not limited to this and may be a landscape screen, etc.

[0276] The space-floating image display device 1000 having the cylindrical housing 1190D of Fig. 20 can be installed on any horizontal surface in the user's environment (such as a desk or table), and can also be stored in a bottle holder in a vehicle, as described below. In other words, the housing 1190D can be stored in an object having a cylindrical recess / hole. This space-floating image display device 1000 can be realized using the retroreflector 5 with a reduced length as described above, so it can be implemented and provided as a relatively small (compact) and portable space-floating image display device.

[0277] [Space-Floating Image Display Device of Example 3: Configuration of Control Unit, etc.] Fig. 21 shows a configuration example of components such as a control unit 1110 as a configuration example of a space-floating image display device 1000 of Example 3. Fig. 21 is based on Fig. 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 Fig. 17) of the display device 1. Also, a real-time rendering unit 2160 is provided corresponding to an embodiment described later. Also, a switch button 2170 is provided corresponding to an 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 is a part that generates image data to be displayed on the space floating image 3 by performing rendering processing almost in real time based on the original data related to the space floating image 3 and operation inputs. The real-time rendering unit 2160 may be implemented as an integral part of the image control unit 1160, etc. As an example described below, when only rendered preset image data is used, the real-time rendering unit 2160 can be omitted.

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

[0280] The configuration example in Fig. 21 includes components for realizing the features and functions described below. Here, some of the functions and operations will be described as an example.

[0281] When the space-floating image display device 1000 displays a character image, which will be described later, on the space-floating image 3, the image control unit 1160 generates image data for display, or reads the image data from a 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 an image on the display surface of, for example, the liquid crystal display panel 11. Based on the image light of the image, after passing through an optical system such as the retroreflecting unit 1101, the character image is displayed inside the statue 3A, which is the space-floating image 3 described above.

[0282] Furthermore, when the space floating image display device 1000 of Example 3 displays a character image, which will be described later, on the space floating image 3, the posture of the character image (display depression angle, which will be described later) can be changed or switched according to the user's operation of the switch button 2170. The image control unit 1160 or the like selects and determines the posture of the character image (display depression angle, which will be described later) according to the operation state of the switch button 2170, and generates image data corresponding to the posture or reads it from memory and displays it on the space floating image 3.

[0283] Regarding the posture of the character image (display depression angle, described below), in one embodiment described below, video data for a plurality of postures with different display depression angles is prepared in advance by a 3D rendering process in an external device (FIG. 29). This video data is stored in advance as presets in, for example, storage unit 1170. When in use, the video control unit 1160 reads the video data for the selected posture from storage unit 1170 and transfers it to video display unit 1102, thereby displaying the character image within the floating-in-space image 3.

[0284] Regarding the posture of the character image (display depression angle, described later), in another embodiment described later, the real-time rendering unit 2160 generates image data of the selected posture by performing a three-dimensional rendering process in almost real time on the original data and operation input, etc. Then, the image control unit 1160 transfers the image data to the image display unit 1102, thereby displaying the character image within the floating image 3 in space.

[0285] Furthermore, in one embodiment described below, the angle adjustment mechanism 3700 (FIG. 37) can adjust and change the arrangement angle of the housing 1190 (particularly the retroreflector 5) and the space-floating image 3. At that time, the space-floating image display device 1000 detects the arrangement angle of the housing 1190 (particularly the retroreflector 5) and the space-floating image 3 based on an angle sensor provided in the angle adjustment mechanism 3700 or an attitude sensor 1113 provided in the housing 1190. Then, the space-floating image display device 1000 can change the state of the attitude (for example, display depression angle) of the character image in the space-floating image 3 by the image control unit 1160 according to the arrangement angle and display it.

[0286] [Display Example of a Space-Floating Image Display Device of a Comparative Example] Figure 22 shows a perspective view and corresponding side view as a display example of a space-floating image 3 on a space-floating image display device of a comparative example. This comparative example, based on Figure 2D, shows a case where a character image 2201 is displayed on the screen (display range 3R) of the space-floating image 3 formed at an inclination angle of 45 degrees with respect to the horizontal plane and the optical plate 150 (stage surface 500). This character image 2201 is an image of the character in an upright basic posture within the screen (display range 3R) of the space-floating image 3. When a user views the character image 2201 of such space-floating image 3 at a depression angle of 45 degrees, for example, it may be difficult for the user to see / feel as if the character is standing on a horizontal plane. In some cases, the character may appear / feel as if lying down on the horizontal plane.

[0287] As described above, the specifications of the optical plate 150 including the retroreflector 5 dictate that, based on the laws of physics, the retroreflection efficiency is highest when the incident angle of the image light on the optical plate 150 is 45 degrees. That is, the brightness peak due to the retroreflected light is highest when the incident angle is 45 degrees, and the brightness peak decreases as the angle deviates from 45 degrees. Therefore, it is necessary / desirable to set the incident angle of the image light on the optical plate 150 to around 45 degrees.

[0288] Furthermore, as described above (FIGS. 15 and 16), when forming a standing image 3A with an inclination angle of 65 degrees, the incident angle deviates from 45 degrees, resulting in a lower brightness peak. When the user views this standing image 3A from the front, the depression angle becomes shallow at 25 degrees, resulting in the floating image 3 appearing dark. In this case, as described above, either the retroreflector 5 becomes longer (FIG. 15) or the size of the screen in the vertical direction becomes smaller (FIG. 16).

[0289] 17 and 23 , based on a predetermined hardware configuration, a floating image 3A, which is a floating image 3 in space, is formed at an inclination angle B of 65 degrees with respect to the horizontal plane of the housing 1190D and the upper surface (stage surface 500) of the optical plate 150. In addition, in Example 3, a prism sheet 300 having a refraction angle C of 20 degrees is provided on the image light exit surface of the display device 1, so that the angle of incidence and exit angle of the image light to the retroreflector 5 are set to α=45 degrees. As a result, when a user observes the 65-degree floating image 3A (for example, a display of a character image 2301) at an observation angle of 45 degrees, an image with a brightness peak B1 can be provided, and the floating image 3 can be viewed as a bright and suitable floating image 3. The depression angle of 25 degrees and the vertical viewing angle / viewing zone range relative to the luminance peak A1 as shown in FIG. 16 can be changed to a depression angle of 45 degrees and a wider vertical viewing angle / viewing zone range relative to the luminance peak B1 as shown in FIG. 17.

[0290] Fig. 23 shows a perspective view and a corresponding side view as a display example of a space-floating image 3 on the space-floating image display device 1000 of Example 3. Fig. 23 shows a case where a character image 2301 is displayed on the space-floating image 3 formed by the optical plate 150 at an angle of 65 degrees with respect to the stage surface 500. The posture of the character image 2301 on the screen of the space-floating image 3 is the same as the posture of the character image 2201 in Fig. 22. As a result, when the user views this character image 2301 at a depression angle of 45 degrees, it is easier for the user to see / feel as if the character is standing on a horizontal plane (particularly the stage surface 500) than in the comparative example.

[0291] 22 and 23, for the purpose of explanation, a rectangle is shown as the frame of the display range 3R of the space floating image 3, but this rectangle is not actually displayed. Also, if you want to present the frame of the display range 3R in the space floating image 3 to the user, you can simply display the frame in a specific color or other way to make it stand out.

[0292] [Rendering of Character Image for Space-Floating Image] FIG. 24 is an explanatory diagram of rendering in a virtual three-dimensional space when generating image data for displaying a character image in the space-floating image 3. When generating a character image, a three-dimensional object (in other words, a three-dimensional model) of the character is placed in a virtual three-dimensional space calculated by a computer, and a virtual camera is positioned and set. As a rendering process, a state / view of the three-dimensional object captured by the virtual camera is generated as a character image / image on a two-dimensional plane. In this embodiment 3, this rendering process is performed in advance by a business operator's computer, or by the real-time rendering unit 2160 ( FIG. 21 ) of the space-floating image display device 1000. The space-floating image display device 1000 displays the character image on the display surface of the liquid crystal display panel 11 by driving and controlling the display device 1 based on the image data of the rendered character image. Image light corresponding to the displayed image forms the space-floating image 3 through an optical system.

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

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

[0295] As shown in Fig. 19 and other figures, in this embodiment 3, a standing figure 3A tilted at 65 degrees is observed from a user's viewpoint position corresponding to the reference observation position, with a state and line of sight looking diagonally downward at a depression angle θB = 45 degrees corresponding to the reference observation direction and reference observation angle. In this embodiment 3, assuming such an observation as a basis, the posture of the character image in the floating-in-space image 3 is variably controlled. The posture of the character image in the floating-in-space image 3 (the display depression angle, described below, and the corresponding rendering display angle of the virtual camera 2402) can be changed according to the reference depression angle θB. Specifically, by selecting the position and shooting direction (particularly the depression angle) of the virtual camera 2402 during rendering as shown in Fig. 24, it is possible to variably set the standing posture at various display depression angles in the two-dimensional image of the character image after rendering as shown in Fig. 25. The display depression angle of such a character image (the rendering display angle of the corresponding virtual camera 2402) can be selected to match the user's observation depression angle θB to, for example, 45 degrees, so as to provide a suitable view.

[0296] [Display Depression Angle of Character Image] FIG. 25 shows example images corresponding to selection and change of the display depression angle of the character image's standing posture when displaying the character image in the Floating in Space Image 3. FIG. 25 shows an example of a character image obtained according to the shooting direction (depression angle, rendering display angle) of virtual camera 2402 in FIG. 24. The upper part of FIG. 25 shows an x-z ​​plane view when viewing a two-dimensional image of the character image from the front, corresponding to when viewing the screen of Floating in Space Image 3 from the front. Image 2501 is a character image / image corresponding to virtual camera C1 with a depression angle of 0 degrees. Image 2502 is a character image / image corresponding to virtual camera C2 with a depression angle of 25 degrees. Image 2503 is a character image / image corresponding to virtual camera C3 with a depression angle of 45 degrees. Image 2504 is a character image / image corresponding to virtual camera C4 with a depression angle of 65 degrees. As in the examples of FIGS. 24 and 25, increasing the depression angle of the virtual camera 2402 results in an image in which the character is viewed from above.

[0297] 25 and 26 described later, the display depression angle of an object image (for example, a character image) is the angle at which the object image tilts forward (in the -y direction in FIG. 24) within the screen / image of the floating-in-space 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] FIG. 26 illustrates the concept of the display depression angle in relation to FIG. 25 . In FIG. 26 , the concept of the display depression angle of a character image 2601 within a statue 3A is shown with the inclination angle B of the statue 3A set to 65 degrees, with the coordinate system (x, y, z) of the floating image 3 in space and the virtual three-dimensional space 2400 superimposed within the spatial coordinate system (X, Y, Z). State A is a Y-Z plan view seen from the side, showing the concept of placing and displaying an image 2501 with a depression angle of 0 degrees within a statue 3A with an inclination angle B = 65 degrees in space. State B is a Y-Z plan view seen from the side, showing the concept of placing and displaying an image 2502 with a depression angle of 25 degrees within a statue 3A with an inclination angle B = 65 degrees in space. The display depression angle is D.

[0299] As in state A, image 2501 in which virtual camera 2402 has a depression angle of 0 degrees will have a display depression angle D of 0 degrees when the forward direction of the character's standing posture (the horizontal plane in the virtual three-dimensional space, the normal direction (y direction) of the screen of Floating in Space Image 3) is taken as 0 degrees as the reference. Similarly, when the vertical direction (z direction) within the screen of Floating in Space Image 3 is taken as 0 degrees as the reference, the display depression angle D will be 0 degrees. As in state B, image 2502 in which virtual camera 2402 has a depression angle of 25 degrees will have a display depression angle D of 25 degrees when the forward direction of the character's standing posture is taken as 0 degrees as the reference. Similarly, when the vertical direction within the screen of Floating in Space Image 3 is taken as 0 degrees as the reference, the display depression angle D will be 25 degrees. When considered in the vertical direction (z-axis) within the screen of the floating in space image 3 corresponding to the image captured by the virtual camera, the standing posture of the character image 2601 is tilted 25 degrees forward (-y) from the vertical direction (z-axis). This tilt corresponds to the display depression angle D of the character image 2601. The same is true for the image 2503 with a depression angle of 45 degrees and the image 2504 with a depression angle of 65 degrees.

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

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

[0302] As described above, an example is shown in which an image 2502 with a display depression angle D of 25 degrees is selected and displayed, corresponding to an inclination angle B of 65 degrees and an observation angle θB of 45 degrees. However, the present invention is not limited to this example. A desired display depression angle D may be selected depending on the design of the inclination angle B and the observation angle θB. Alternatively, multiple display depression angles D may be provided as options, allowing the user to select a display depression angle of their choice. While four values, including 0 degree, are shown as examples for the angle and display depression angle of the virtual camera 2402 in FIGS. 24 and 25 , the present invention is not limited to this example and may instead be set as multi-level values ​​or continuous values.

[0303] As in the above example, in this embodiment 3, based on the hardware configuration (FIG. 17, etc.) of the space floating image display device 1000, the character image is displayed in the space floating image 3 at an inclination angle B=65 degrees with respect to the horizontal axis. In addition, in this embodiment 3, the software configuration, particularly the stereoscopic rendering process, displays the character image at a selected display depression angle D (in other words, the stereoscopic rendering display angle) of, for example, 25 degrees in the space floating image 3. This makes it easier for the user to see / feel as if the character is standing on a horizontal plane when looking at the character image in the statue 3A.

[0304] [Generation and Display of Character Image at Selected Display Depression Angle] One feature of the third embodiment is that when displaying a character image on a screen of a statue 3A at a 65-degree tilt angle B based on the hardware configuration shown in FIG. 19 , the following software processing is performed. That is, as shown up to FIG. 26 , the space-floating image display device 1000 generates video data of the character image, particularly based on a rendering process, 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. Alternatively, the space-floating image display device 1000 reads video data of the character image at the selected desired display depression angle from preset video data. In the third embodiment, video data of the character image that has been previously rendered to a predetermined display depression angle is generated and stored in memory. When a user uses the system, they simply select and read the video data of the character image from memory, eliminating the need for rendering. In this case, the load on the rendering process on the computer can be reduced, and a system using an inexpensive computer with low computing performance can be realized.

[0305] In the third embodiment, the display depression angle of a character image is set or changed in accordance with the user's assumed reference observation angle (and the vertical viewing angles centered on the reference observation angle). This configuration may be implemented in such a way that a single reference observation angle is fixed as a basic setting, and a single preferred display depression angle corresponding to the reference observation angle is fixedly set. Alternatively, multiple reference observation angles may be assumed, and a preferred display depression angle corresponding to each reference observation angle may be selected or set. For example, the user may be able to select the reference observation angle to be used from multiple observation angles through user input or user settings. Then, a preferred display depression angle matching the selected observation angle may be selected from the multiple display depression angles and applied. Alternatively, the user may be able to select the display depression angle to be used from multiple display depression angles through user input or user settings.

[0306] In particular, as a basic configuration of Example 3, the operator predefines several reference observation angles and display depression angles, and prepares image data of character images rendered at each display depression angle as presets / defaults and stores them in memory. The space floating image display device 1000 applies the display depression angles specified by user settings, etc.

[0307] As a modification of the third embodiment, the space floating image display device 1000 uses the real-time rendering unit 2160 (FIG. 21) to generate a character image with a display depression angle selected in accordance with the reference observation angle.

[0308] [Switching Display Depression Angle Using a Physical Button] In this third embodiment, a user's desired display depression angle can be selected and used from a plurality of display depression angles provided as options based on a user's operational input. This operational input may be voice input, an operation in the air, or a user setting in advance. In particular, in this third embodiment, by pressing a switch button 2170 ( FIG. 21 ), which is a physical button provided on the housing 1190, it is possible to switch to a character image with a desired one of a plurality of display depression angles.

[0309] FIG. 27 shows a configuration example in which a physical switch button 2170 (FIG. 21) is provided on the housing 1190D. The user can toggle (cyclically) the display depression angle by pressing the switch button 2170. In state A, the display depression angle of the character image 2701 in the floating-in-space image 3 is 0 degrees, which corresponds to image 2501 in FIG. 25 . Suppose the user wants to change the posture of the character image. When the user presses the switch button 2170 once with their finger 235, the state transitions to state B. In state B, the display depression angle of the character image 2702 in the floating-in-space image 3 is 25 degrees, which corresponds to image 2502. When the user presses the switch button 2170 again, the state transitions to state C. In state C, the display depression angle of the character image 2703 in the floating-in-space image 3 is 45 degrees, which corresponds to image 2503. If the user presses switch button 2170 again, the state transitions to state D. State D is a state in which the display depression angle of character image 2704 in floating-in-space image 3 is 65 degrees, and corresponds to image 2504. If the user presses switch button 2170 again, the state transitions back to state A.

[0310] While this example shows how four different display depression angles can be switched by operating one button, other configurations are possible. For example, a button may be provided for each display depression angle. Alternatively, a forward rotation button and a backward rotation button may be provided for continuously rotating the display depression angle back and forth.

[0311] In this embodiment, the case where a character image is displayed on the floating image 3 in space has been described, but this is not limited to this, and the above-mentioned control of the display depression angle etc. can be similarly applied to any object image, especially to object images generated by rendering based on a three-dimensional model.

[0312] [Changing the display depression angle by user setting] In this embodiment 3, a character image with a desired display depression angle can be selected and set by the user. As a user setting function, a user setting screen may be provided in the floating image 3, and the display depression angle may be selected by the user's operation input (for example, operation in the air).

[0313] FIG. 28 shows a display example that allows the user to set the display depression angle on a GUI screen 2800 using floating-in-space images 3. In user settings on the GUI screen 2800, a guide such as "Please select the posture of the character image" is displayed, and a display depression angle selection button 2801 is displayed. The user can set the display depression angle by pressing the desired display depression angle selection button 2801, for example, by manipulating the finger 235 in the air. A preview image 2802 at the display depression angle corresponding to the pressed selection button 2801 is also displayed. Alternatively, the display depression angle may be set using a continuous numerical value. Furthermore, when using a method for selecting the display depression angle by voice input, the user can simply input, for example, "25 degrees" into the microphone.

[0314] The example of Figure 28 shows the setting of the display depression angle for a certain user and for a certain character image. Such user setting may be possible for each user and for each character image. When setting for each user is possible, recognition of each user is necessary. This may be achieved by, for example, photographing the user with camera 1180A of imaging unit 1180 in Figure 19 and performing facial recognition or the like to recognize the user. Furthermore, the character image itself used by the user may be selectable from multiple options, and the posture and the like may be set for each character image.

[0315] [Selection of Video Data for Preset Display Depression Angles] In the third embodiment, a plurality of character images corresponding to a plurality of display depression angles may be generated in advance by rendering and stored in memory (for example, storage unit 1170 in FIG. 21 ). The plurality of display depression angles may have, for example, four values ​​as shown in FIG. 25 . When used by a user or when setting the display depression angles, a desired one can be selected and switched from the character images for the plurality of display depression angles in accordance with user input or other operations.

[0316] 29 shows an example of the configuration of the space floating image display device 1000 in which one of video data of a character image with a plurality of display depression angles is selected and switched for display. An external device 2000, such as a business's PC or server, has a data set 2013 including a 3D model 2001 that is the source of the character image in advance. The data set 2013 may also include motion information 2003, virtual light source information 2004, virtual camera information 2005, audio data 2006, etc.

[0317] In advance, the image processing unit 2011 of the external device 2000 performs rendering processing on the three-dimensional model 2001 to generate image data 2002 for displaying a two-dimensional character image on the space-floating image 3 (corresponding display unit 1502). Image data 2902 corresponding to the image data 2002 is installed as preset image data in a memory such as the storage unit 1170 (FIG. 21) of the space-floating image display device 1000. Alternatively, the space-floating image display device 1000 may download and acquire the image data 2002 or the data set 2013 from the external device 2000 via network communication as appropriate.

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

[0319] Video processing unit 1501 receives instruction information regarding the display depression angle based on user operation input via operation input unit 1107 (including switch button 2170 described above), detection information by user operation detection mechanism 1504, or pre-set user information 2903. Based on the instruction information, video processing unit 1501 selects and reads out video data 2902 corresponding to the specified display depression angle from memory.

[0320] 29 also illustrates a case where the space-floating image display device 1000 holds a three-dimensional model 2901, which is the original data of the character image. The space-floating image display device 1000 may acquire the three-dimensional model 2001, etc. of the original data from the external device 2000, and store it as the three-dimensional model 2901. In this case, the image processing unit 1501 (particularly the real-time rendering unit 2160 in FIG. 21) may generate image data 2902 by performing rendering processing in almost real time based on the three-dimensional model 2901.

[0321] [Real-time Rendering of Images with Display Depression Angle] While a character image with a preset display depression angle may be used as described above, in another configuration example, the display depression angle may be a continuous value within a predetermined range, and a character image with that display depression angle may be generated and displayed by a rendering process in near real time according to a display depression angle selected from the range. The display depression angle can be determined in various ways. For example, the display depression angle may be directly specified by a user operation input or user setting. Alternatively, even without a user specification, the space-floating image display device 1000 may detect / estimate a reference observation angle, etc., and calculate and automatically determine a suitable display depression angle based on the detected / estimated value. In the latter case, for example, the image processing unit 1501 estimates / calculates the user's actual viewpoint position (e.g., the center point between the eyes) from a captured image of the user's face and its vicinity captured by the camera of the imaging unit 1180. The video processing unit 1501 estimates and calculates the observation angle (depression angle) corresponding to the calculated viewpoint position. The video processing unit 1501 then determines a suitable display depression angle that matches the observation angle. For example, if the detected / estimated observation angle is 50 degrees, which is 5 degrees larger than the reference 45 degrees, the video processing unit 1501 may determine the display depression angle to be 30 degrees, which is 5 degrees larger 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 three-dimensional model 2901 through rendering processing by the real-time rendering unit 2160 ( FIG. 21 ).

[0322] [Display elevation angle of character image face] In this embodiment 3, when displaying a character image in the floating image 3 in space, not only is the display depression angle controlled as described above, but the display elevation angle of the face may also be controlled so that the character's face faces toward the user's viewpoint.

[0323] 30 is an explanatory diagram of a display example in which the display elevation angle of the face is controlled so that the character's face faces the user's viewpoint when displaying a character image on the floating image 3. This display elevation angle is an angle at which the character's face looks up toward the user. Setting and changing this display elevation angle is achieved by software processing of the image data, particularly by rendering processing.

[0324] First, as a premise, there is control of the basic standing posture and display depression angle of the character image, as shown in the above-mentioned Figure 25 etc. Then, the image processing unit 1501 (Figure 29) controls to change the display elevation angle of the face part in the floating image in space 3, so that the face of the character image faces in a direction close to the observation angle θB of the user, in accordance with the observation angle θB of the user.

[0325] In this third embodiment, an idling state of the character image is first established as a first control state / display state. The idling state is a state in which there is no predetermined action from the user to the character image, and is a state in which 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 posture with a predetermined display depression angle in FIG. 25 . Here, for example, assuming an observation angle θB = 45 degrees, the standing posture is set to a display depression angle = 25 degrees, as in image 2502. This standing posture is a posture that appears to be standing at an angle of 90 degrees relative to the horizontal plane.

[0326] FIG. 30 also shows examples of an 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 FIG. 25. Note that in the idling state, the character image may be stationary, or may be moving in a predetermined manner. In the idling state, a predetermined message or sound may be output. In the idling state, for example, the image may show the character sleeping.

[0327] In the idle state, the floating-in-space image display device 1000 accepts a predetermined action (first action) by the user, such as voice input, mid-air operation, or physical button operation. State B is a state of a user action. For example, when using mid-air operation, the user may touch the screen of the floating-in-space image 3 with their finger 235. For example, the mid-air operation detection sensor 1351 in FIG. 21 (which may be an electrostatic sensor, an infrared sensor, a distance sensor, a camera, or the like) detects the touch operation. It may also be detection of pressing a predetermined physical button. The image processing unit 1501 (FIG. 29) inputs and receives such operation input information or detection information. In the case of voice input, it may also be detection of a predetermined wake-up keyword in the voice.

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

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

[0330] State C is a second control state / display state in which the face of the character image looks up at the user at a predetermined display elevation angle (in other words, a reaction state) (also corresponding to state B in FIG. 31 described below). Here, for example, the character image 3002 is drawn with the trunk, such as the torso and legs, based on a posture with a display depression angle of 25 degrees, the same as in the idling state, and the display content is changed so that the portion including the face faces toward 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 FIG. 31.

[0331] The video processing unit 1501 uses video data for displaying a character video in which the character's face looks diagonally upward at a selected display elevation angle. As with the control of the display depression angle described above, this video data is prepared in advance as a plurality of video data corresponding to a plurality of display elevation angles that have been rendered as presets, and then selected and read out. Alternatively, as described above, a character video at a selected desired display elevation angle may be generated by rendering in near real time at the time of use.

[0332] The user views the character image with the above display elevation angle of the floating image 3 at a standard observation angle (for example, a depression angle of 45 degrees). This gives the user the impression that the character is responding to the user's action and turning towards them. This embodiment can provide a floating image with a three-dimensional feel and high interactivity.

[0333] 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 do you want to do," "What do you want to know," etc.) or a GUI displayed on the floating image 3 in space, or may be audio output. During the response time in the second control state, the user may further input operations (e.g., selection or question input) to the character, GUI, etc.

[0334] For example, the screen 3003 of the floating-in-space image 3 in state D shows an example of a call display. On this screen 3003, a message (such as "Please select") from the character image 3002 at the display elevation angle is displayed, and option buttons are also displayed. The user can select the desired option button. The floating-in-space image display device 1000 then performs a predetermined process according to the user's input. For example, if this floating-in-space image 3 is used as a GUI for an in-car system, it is possible to realize guides and instruction inputs regarding the functions of the in-car system using the character image.

[0335] In another example of use, when this space floating image display device 1000 is installed at a reception desk of a facility, the space floating image 3 may display the GUI and guide of the reception desk together with the character image.

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

[0337] Regarding the function of the face display elevation angle, the user may be allowed to set a desired display elevation angle on a user setting screen, as in Fig. 28. Also, the face display elevation angle may be allowed to be switched in response to the operation of a physical button, as in Fig. 27.

[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 three-dimensional space 2400 and an image of the character video corresponding to a front view of the statue 3A. State A is a case where the display depression angle of the basic upright standing posture is 45 degrees, and the shooting direction (depression angle) of the virtual camera C3 is 45 degrees. The user's reference observation angle θB is a depression angle of 45 degrees. The image 2503 on the right is a character video corresponding to the display depression angle = 45 degrees described above (Figure 25).

[0339] In character 3101, face portion 3102 includes face 3103, neck, chest, and shoulders. Face 3103 of character 3101 faces directly forward, at an angle of 0 degrees, with respect to horizontal axis H in virtual three-dimensional space 2400, and this is defined as direction 3104 of face 3103. This state is taken as the basis, and display elevation angle E=0 degrees.

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

[0341] Note that the display elevation angle E here is the angle relative to the horizontal axis H in the virtual three-dimensional space 2400, but as in Figure 26, the display elevation angle E of the face of the character image within the standing figure 3A having the tilt 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, the axis 2620 in Figure 26).

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

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

[0344] For example, when using presets, character 3201 with a display elevation angle E of 0 degrees is selected in the aforementioned idling state ( FIG. 30 ). Furthermore, when an action is received and the vehicle is in a response state, for example, in the case of a selection signal of 25 degrees, character 3202 is selected. In the case of a selection signal of 45 degrees, character 3203 is selected. In the case of a selection signal of 65 degrees, character 3204 is selected. Alternatively, as described above, when the display elevation angle is automatically determined by estimating the user's observation angle, for example, the display elevation angle of the face may be determined to be 50 degrees when the observation angle is a depression angle of 50 degrees.

[0345] [Appearance of Character Image] Figure 33 shows a perspective view and a side view as an explanatory diagram of the subjective appearance when viewing a character image of a figurine 3A at a depression angle of 45 degrees and a tilt angle B = 65 degrees from a user's viewpoint, based on the configurations of Figures 20, 23, 25, etc. The figurine 3A, which is the space-floating image 3, is formed at 65 degrees relative to the upper surface (stage surface 500) of the optical plate 150 of the space-floating image display device 1000, and a character image 3301 is displayed within the figurine 3A by controlling the display depression angle to, for example, 25 degrees. The user observes this character image 3301 at a depression angle of 45 degrees as an observation angle θB. As shown in the perspective view, this makes it easy for the user to see / feel as if the character is standing on a horizontal plane (particularly the stage surface 500).

[0346] [Comparative Example: Vertical Viewing Angle When Observation Angle Deviates from Standard] In the examples described above, a configuration example has been described in which the optical plate 150 including the retroreflector 5 is placed on a horizontal plane, the inclination of the standing image 3A is 65 degrees, and the user observes the image at a depression angle of 45 degrees as the standard observation angle. However, in actual usage environments and situations, as shown in FIG. 34 , the observation angle from the user's viewpoint may deviate from the preferred angle range of 45 degrees ±X.

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

[0348] 17, in this comparative example, an optical plate 150 including a retroreflector 5 is disposed on a horizontal plane (horizontal axis H). The display device 1B is disposed at 65 degrees relative to the optical plate 150, and the image 3A is formed at 65 degrees relative to the optical plate 150. The length of the optical plate 150 in the depth direction (Y direction) is PL1.

[0349] A chief 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 (the aforementioned refraction angle C = 20 degrees) and enters the optical plate 150 at point P at an incident angle α = 45 degrees. The retroreflected light from point P is imaged at the center (point Ct1) of the image 3A. A light 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 the retroreflected light forms an image at the lower end (point Bt1) of the image 3A. A light 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 the retroreflected light forms an image at the upper end (point Tp1) of the image 3A. When the user observes this statue 3A from the viewpoint position 3400 at a depression angle of 45 degrees, which is the reference observation angle θB, the entire range above and below the screen of the statue 3A can be clearly seen.

[0350] In contrast, when a user observes this figurine 3A from viewpoint 3401 at a depression angle of approximately 30 degrees, which is the observation angle θ1, the following occurs. Consider a line of sight 3402, which looks from viewpoint 3401 at the center (point Ct1) of figurine 3A, as the reference point. In the direction from the center (point Ct1) of the screen of figurine 3A toward the optical plate 150 and the direction from the bottom 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 top end (point Tp1) of the screen of figurine 3A toward the optical plate 150, the optical plate 150 is not reached, but rather a point S where the optical plate 150 is not present. In the direction 3404 from point T where figurine 3A is located, a point R at the rear end of the optical plate 150 is reached.

[0351] Therefore, when viewed from viewpoint 3401, in a range 3420 from point T to the bottom end (point Bt1) on the screen of statue 3A, the image can be seen, or an image with lower brightness than when viewed from viewpoint 3400 can be seen. However, in a range 3410 from point T to the top end (point Tp1) on the screen of statue 3A, the image cannot be seen, or only an image with lower brightness than when viewed from viewpoint 3400 can be seen.

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

[0353] As in the above comparative example, assuming a range of reference observation angles, if the actual user's viewpoint position and observation direction fall within this standard, that is, if the depression angle is within a range of 45 degrees ± X degrees, the entire vertical range of the figure 3A is visible. However, if the actual user's viewpoint position and observation direction deviate from the standard, that is, if the depression angle is outside the range of 45 degrees ± X degrees, then as in the above example, part of the figure 3A cannot be seen, and the effective vertical viewing angle / viewing zone range is narrowed.

[0354] In order to deal with the situation where the image of the figurine 3A on the screen is partially invisible to the user (the screen is cut off), as described above, a configuration such as that shown in FIG. 35 may be used as one example.

[0355] [Example of tilted optical plate arrangement] Figure 35 is a Y-Z plane view showing the optical system of the space-floating image display device 1000 of one example. In the example of 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 (depression angle of 45 degrees), as in Figure 34. In other words, in the example of Figure 35, this observation angle θ1 can be considered as a new reference observation angle. This observation angle θ1 is an angle assumed in the environment and situation in which the user actually uses the space-floating image display device 1000.

[0356] Furthermore, in this embodiment, the optical plate 150 is tilted at a predetermined angle (γ) from the horizontal plane (horizontal axis H). In this embodiment, the predetermined angle γ is 10 degrees. This tilt at angle γ is such that the rear (+Y) end of the optical plate 150 is raised upward (+Z) relative to the front (-Y) end in the Y direction corresponding to the horizontal axis H shown in the figure; in other words, the optical plate 150 is rotated in the depression angle direction around the X axis. The length PL1 of the optical plate 150 remains unchanged from that shown in FIG. 34.

[0357] In this embodiment, the inclination angle B of the floating image 3 in space is maintained at 65 degrees relative to the horizontal plane, as in the previous embodiment ( FIG. 17 ). Therefore, the angle of the floating image 3 relative to the optical plate 150 is set to (65 degrees - γ) = 55 degrees. Correspondingly, the display device 1B is positioned symmetrically with the optical plate 150 as a mirror image, so the angle relative to the optical plate 150 is set to 55 degrees, and the angle relative to the horizontal plane is set to (55 degrees - γ) = 45 degrees. The relationship between the display device 1B and the optical plate 150 maintains the same configuration as in FIG. 17 , using the prism sheet 300 to set the incident angle α to 45 degrees, but the arrangement is rotated 10 degrees overall from FIG. 17 . Furthermore, the refraction angle of the prism sheet 300 in FIG. 35 is set to C = 10 degrees in order to set the incident angle α to 45 degrees.

[0358] In Fig. 35, when a user observes the space floating image 3 at an observation angle θ1, a direction 3403 passing through the top edge of the screen (point Tp1) reaches point R at the rear edge (left edge in the drawing) of the optical plate 150. This direction 3403 is the incident and exit direction of the corresponding image light. As a result, when a user observes the space floating image 3 at an observation angle θ1, the top of the screen of the space floating image 3 is not cut off, and the entire range of the top and bottom of the screen is visible, and the vertical viewing angle / viewing range in which the image can be effectively viewed can be expanded compared to the case of Fig. 34.

[0359] The configuration example of FIG. 35 assumes use at a depression angle θ1, and the optical plate 150 is fixed 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 a range of 10 degrees ± Z, for example, 10 degrees ± 5 degrees. Increasing the angle γ to, for example, 15 degrees or 20 degrees, increases the vertical viewing range accordingly. However, from the user's perspective, the optical plate 150 may appear / feel like the floor on which the character stands relative to the character image within the figurine 3A. Therefore, if the optical plate 150 as the floor is tilted too far from the horizontal, the character may appear / feel like it is standing on an oblique surface, which may cause discomfort to some users and reduce the effect of the character appearing to be standing on a horizontal surface. Therefore, in this embodiment, a balance is struck between the user's observation angle θ1, the size of the vertical viewing range, and the effect of the character image of statue 3A appearing to be standing, and the angle γ is designed to be 10 degrees ±5 degrees.

[0360] [Modification: Addition of Transparent Plate] Figure 36 shows a modification of the configuration of Figure 35. The main difference between this modification and Figure 35 is that the transparent member 100 of the optical plate 150 is removed, and a transparent plate 3600 is newly placed on a horizontal surface above the retroreflector 5. This transparent plate 3600 may be the same as the transparent member 100, or may be a different member. The transparent plate 3600 may be placed above the optical plate 150 consisting of the transparent member 100 and the retroreflector 5. This transparent plate 3600 is a device that transmits image light. When a user looks at the figurine 3A, the transparent plate 3600, placed on a horizontal surface, is used as a floor, and the character image is likely to appear as if it is standing on that horizontal floor.

[0361] Furthermore, based on the configuration of FIG. 35, it is also possible to configure the inclination angle of the optical plate 150 to be variable rather than fixed, as follows.

[0362] <Example 4> A space-floating image display device of Example 4 will be described. Fig. 37 shows a configuration example of a space-floating image display device 1000 of Example 4. Example 4 is configured based on the configuration of Fig. 35, and is configured such that the angle of inclination of the optical plate 150 can be set variably rather than fixedly by an angle adjustment mechanism 3700. In addition, the space-floating image display device 1000 of Example 4 has a housing structure that can be accommodated and mounted in a cylindrical structure such as an in-vehicle bottle holder (in other words, a cup holder or a drink holder).

[0363] The positional relationship between the user's viewpoint and the space-floating image 3 may vary depending on the environment and situation (e.g., inside a vehicle) in which the user uses the space-floating image display device 1000. For example, this positional relationship arises depending on the user's height and sitting height, the position and orientation of the head, and the position and orientation of the bottle holder in which the space-floating image display device 1000 is housed. Depending on this positional relationship, the observation angle and vertical viewing angles described above may vary. For example, there are various possible locations for the bottle holder inside a vehicle, such as near the air conditioner or near the shift lever.

[0364] Therefore, in Example 4, a mechanism is provided for adjusting the position of the figurine 3A and the display content of the character image using hardware and software configurations so as to accommodate observation angles that vary depending on the positional relationship. Specifically, in Example 4, an angle adjustment mechanism 3700 is provided in the housing 1190. In other words, the angle adjustment mechanism 3700 is a swing mechanism that can rotate back and forth in the depth direction (Y direction) around a predetermined axis 3731 (X axis). This angle adjustment mechanism 3700 can adjust the direction and position of the formation of the floating image 3 in space, which is the figurine 3A, to match the user's observation angle, etc. The angle adjustment mechanism 3700 can adjust the angle of the arrangement of the entire system including the display device 1B, the optical plate 150, and the floating image 3 in space.

[0365] In the fourth embodiment, the user can manually move the housing 1190 (particularly the upper housing 1190B) back and forth to adjust and set the angle of the angle adjustment mechanism 3700 (in other words, the swivel angle or rotation angle). This swivel angle may be variable continuously or in several stages. In the fourth embodiment, a plurality of predetermined stages of swivel angles are defined and prepared in advance. In addition, the above-mentioned preset image data is prepared for each angle in accordance with each swivel angle. Furthermore, the posture of the character image (such as the above-mentioned display depression angle) as the display content of the figurine 3A can be adjusted and set by user settings, etc. This allows for efficiency and low cost to be achieved.

[0366] The examples from Fig. 37 onwards show examples of configurations that can be mounted in a bottle holder in a vehicle. The examples before Fig. 37 are not limited to mounting in a bottle holder and can be used in various environments.

[0367] [Housing and Swing Mechanism Mountable on a Bottle Holder] In FIG. 37 , the housing 1190 in Example 4 is broadly divided into 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 portion that can be housed within a cylindrical bottle holder 3750 (only a portion of which is shown diagrammatically), has a predetermined holding mechanism, etc., and is held relative to the bottle holder. In other words, the lower housing 1190A is a bottle holder mounting mechanism. The upper housing 1190B can be rotated back and forth in the depth direction (Y direction) around a shaft 3731 relative to the lower housing 1190A by the angle adjustment mechanism 3700, thereby adjusting the placement angle (swing angle). The upper housing 1190B is held stationary at a selected placement angle (swing angle). The angle of placement (swivel angle) of upper housing 1190B can be changed in response to manual operation of angle adjustment mechanism 3700 and upper housing 1190B by the user.

[0368] The arrangement of the upper housing 1190B in Fig. 37 is based on Fig. 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 of Fig. 37 is set to 0 degrees as the basic angle R1. The arrangement of Fig. 37 is set to the first state, the basic state. The swivel angle set by the angle adjustment mechanism 3700 is set to R1 = 0 degrees, with the position indicated by the dashed line in the figure as the basic position.

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

[0370] In the configuration example of Fig. 37, in addition to the display device 1B, a control board 3710 is also housed within upper housing 1190B. Control board 3710 corresponds to control board 350 in Fig. 19 and is an implementation corresponding to control unit 1110 in Fig. 21 and video processing unit 1501 in Fig. 29. A system circuit included in control board 3710 performs processes such as controlling the idling and response display operations described above (Fig. 30) as a standalone operation of character image 3701 of statue 3A.

[0371] 37 , the character image 3701 in the statue 3A is displayed in a posture that makes it appear 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 regarded as the stage surface 500, the positioning angle of the standing posture of the character image 3701 is, with respect to the vertical direction 3702 as the reference, 90 degrees + γ to 100 degrees with respect to the front side of the stage surface 500 at an angle φ1, and 90 degrees - γ or 55 degrees + 25 degrees to 80 degrees with respect to the rear side of the stage surface 500.

[0372] The tilt angle γ of the optical plate 150 relative to the stage surface 500 is relatively small at 10 degrees. Because the optical plate 150 is optically transparent, this tilt is not particularly noticeable to the user, and the character is likely to appear as if it is standing on a generally horizontal plane. Therefore, when the user observes the character image 3701 of the figurine 3A at an observation angle θ1, the character is likely to appear / feel as if it is standing on a generally 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 this case, the basic posture angle relative to the stage surface 500 will be 90 degrees. If a 90-degree angle relative to the stage surface 500 is desired, such control can also be applied.

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

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

[0375] The angle adjustment mechanism 3700 is a mechanism that rotates the upper housing 1190B back and forth around the shaft 3731 and can stably maintain a stationary state at each of a plurality of predetermined angles within a predetermined angle range. By adjusting the swing angle of the angle adjustment mechanism 3700, the arrangement angle of the optical plate 150 and the figurine 3A can be adjusted to a desired angle selected by the user within a predetermined range. In this fourth embodiment, a case where three preset types and three preset angles can be selected is described ( FIGS. 37 to 39 ).

[0376] The portion illustrated as bottle holder 3750 may be a receiving portion that is part of an actual bottle holder. FIG. 40 shows an example of such a bottle holder as a modified example. Receiving portion 3750b in FIG. 40 is held inside the cylindrical side surface of the opening of bottle holder 3750c. Mounting portion 3730 is accommodated and held in hole 3751 of receiving portion 3750b. Receiving portion 3750b may be part of the bottle holder, or may be part of the space-floating image display device 1000 (particularly, lower housing 1190A). As will be described later, since there are various specifications for bottle holders, such as diameter, it is more preferable to provide a mechanism in lower housing 1190A that allows the space-floating image display device 1000 to be accommodated and mounted in accordance with various specifications.

[0377] In the configurations of Figures 19 and 37, it is also possible to provide terminals or the like as input / output interfaces in 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] FIG. 38 shows a state in which the upper housing 1190B is tilted forward as an example of another arrangement angle using a different pivot angle (denoted as R2) compared to FIG. 37 . For example, if a user manually tilts the upper housing 1190B forward in the Y-axis direction, the angle adjustment mechanism 3700 can adjust the upper housing 1190B to the state shown in FIG. 38 . The state shown in FIG. 38 is the second state, or forward tilt 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 relative positions of the display device 1B and other components within the upper housing 1190B are 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. Furthermore, the tilt angle of the figurine 3A is approximately 65 degrees + R2 or γ + R2 + 55 degrees, or approximately 85 degrees, with respect to the horizontal axis H, which is roughly close to vertical.

[0379] The user's observation angle assumed corresponding to the second state of FIG. 38 is θ1B. Observation angle θ1B may be different from observation angle θ1 of FIG. 37, but here, θ1B = θ1 = approximately 30 degrees. The user's viewpoint position is viewpoint position 3501B. Viewpoint position 3501B may be different from viewpoint position 3501 of FIG. 37. Space-floating image display device 1000 controls the display of character image 3801 of statue 3A according to this second state. As an example of such display control, character image 3801 is displayed at a selected display depression angle D, for example. This display depression angle D is set to approximately 5 degrees here. In this case, as shown in the figure, the character's basic posture angle is closer to vertical direction 3702. Furthermore, the positioning angle of the standing posture of character image 3801 relative to the front side of stage surface 500 is set to angle φ2, which is 90 degrees + γ + R2, or approximately 120 degrees.

[0380] FIG. 39 shows a rearward tilted state as an example of another arrangement angle of the upper housing 1190B using a different pivot angle (denoted as R3) compared to FIG. 37 . For example, if a user manually tilts the upper housing 1190B toward the rear in the Y-axis direction, the angle adjustment mechanism 3700 can achieve the state shown in FIG. 39 . The state shown in FIG. 39 is the third state, a rearward tilted state. In the third state, the angle R3 set by the angle adjustment mechanism 3700 is approximately 20 degrees rearward relative 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. Furthermore, the tilt angle of the figurine 3A is approximately 45 degrees, from 65 degrees -R3 or γ-R3+55 degrees with respect to the horizontal axis H.

[0381] The user's observation angle assumed in accordance with the third state of FIG. 39 is designated as θ1C. Observation angle θ1C may be different from observation angle θ1 in FIG. 37, but here θ1C = θ1. The user's viewpoint position is designated as viewpoint position 3501C. Viewpoint position 3501C may be different from viewpoint position 3501 in FIG. 37. The space-floating image display device 1000 controls the display of character image 3901 of statue 3A in accordance with this third state. As an example of such display control, character image 3901 is displayed at a selected display depression angle D, for example. This display depression angle D is set to approximately 45 degrees here. In this case, as shown in the figure, the character's basic posture angle is closer to vertical direction 3702. Furthermore, the positioning angle of the standing posture of character image 3901 relative to the front side of stage surface 500 is set to angle φ3, which is 90 degrees + γ - R3, or approximately 80 degrees.

[0382] In the above-described fourth embodiment (FIGS. 37 to 39), several options for the angle of the swing angle of the angle adjustment mechanism 3700 are predefined. For example, as shown in FIGS. 37 to 39, a configuration is shown in which the user can manually select from three angles (e.g., 0 degrees, +20 degrees, and -20 degrees). The angle adjustment mechanism 3700 stably maintains the selected angle using a mechanism such as a torque hinge on the shaft 3731. For example, a user may use the space-floating image display device 1000 housed and installed in a bottle holder in a vehicle. In this case, the observation angle may vary depending on the positional relationship between the bottle holder and the user's viewpoint, and the required vertical viewing range may change. To address this, in this fourth embodiment, the angle adjustment mechanism 3700 can be used to adjust the position of the space-floating image 3 by rotating it back and forth.

[0383] By adjusting this swivel angle, the figurine 3A can be positioned at a desired tilt angle (e.g., 65 degrees, 85 degrees, or 45 degrees) to match the user's observation angle and required viewing range. The space-floating 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 figurine 3A achieved by this hardware configuration. For example, the display depression angle D for each state is 25 degrees, 5 degrees, or 45 degrees, and from the user's perspective, the image appears upright relative to the horizontal plane and remains unchanged. This allows the display of character images and vertical viewing ranges appropriate for each angle to be achieved, regardless of the swivel angle set by the angle adjustment mechanism 3700.

[0384] The options for the swing angle adjustable by the angle adjustment mechanism 3700 are not limited to the above three types of angles. The angle adjustment mechanism 3700 may be configured to allow for stepwise change of a plurality of predefined types of angles as options. For example, if only the above three types of angles are used, a transition between the first state in FIG. 37 and the second state in FIG. 38 is possible, and a transition between the first state in FIG. 37 and the third state in FIG. 39 is possible. Furthermore, if two types of angles are added between the above three types of angles to provide five levels, a transition from the first state in FIG. 37 to a fourth state, which is an intermediate angle between the first and second states, and a fifth state, which is an intermediate angle between the first and third states, is possible.

[0385] Depending on the implementation, the angle adjustment mechanism 3700 may be configured to continuously change the oscillating angle within a predetermined upper and lower limit angle range. For example, the angle may be arbitrarily selected from a continuous range of angles with the forward tilt angle in FIG. 38 and the backward tilt angle in FIG. 39 as the upper and lower limits. In this case, the angle adjustment mechanism 3700 is also configured to stably maintain the selected angle.

[0386] The above-described fourth embodiment shows a configuration of a type that can be accommodated in a bottle holder, in which the inclination angle γ of the optical plate 150 is basically 10 degrees. However, this is not limited to this, and a configuration in which the inclination of the optical plate 150 is 0 degrees and the horizontal plane is basically (first state) based on the configuration of Figure 19 is also possible.

[0387] As shown in FIG. 41 , one angle selectable by the user within the angle range adjustable by the angle adjustment mechanism 3700 may include an angle at which the optical plate 150 is in a horizontal plane. In the modified example shown in FIG. 41 , when the angle adjusted by the angle adjustment mechanism 3700 is set to RX, the optical plate 150 is positioned along the horizontal axis H. This angle may be added in addition to or instead of the three swing angles shown in FIGS. 37 to 39 . In the example shown in FIG. 41 , when the character image 4101 of the figurine 3A is displayed at angle RX, a predetermined display depression angle D is set, so that the basic posture angle is in the vertical direction 3702. In this case, the character image 4101 appears to be standing on the stage surface 500, which is a horizontal plane.

[0388] As a modified example, angle adjustment mechanism 3700 may be provided with a drive mechanism such as a motor. Control board 3710 may automatically control the drive mechanism to change the swing angle of angle adjustment mechanism 3700.

[0389] [Variable Control of Display Depression Angle According to Swivel Angle] Although one example has already been shown above, the space-floating image display device 1000 of Example 4 may variably control the display content of the character image according to the arrangement angle state of the upper housing 1190B and the space-floating image 3 by the angle adjustment mechanism 3700. The space-floating image display device 1000 controls the display so that the display depression angle D of the character image is selected from presets according to the state of the swing angle, for example. When the arrangement angle is changed according to manual operation of the angle adjustment mechanism 3700, the space-floating image display device 1000 changes the display depression angle of the character image to match the changed arrangement angle and displays it.

[0390] There are various possible ways to control the display depression angle of the character image according to the swivel angle and the positioning angle of the floating image 3. Some examples are given below. One control example is to control the display depression angle to be constant at each swivel angle. Another control example is to select and adjust each display depression angle so that the angle of the character's standing posture appears constant at each swivel angle.

[0391] [Control for maintaining the posture of the character image unchanged] Figure 42 shows an example of control of the display depression angle according to the head swing angle. Any of the control examples may be adopted. This example is based on the premise that the above-mentioned three types of head swing angle (Figures 37 to 39) can be selected. Figure 42 illustrates a conceptual image by extracting the standing statue 3A and the like from Figures 37 to 39.

[0392] 37 to 39 , in the first state (R1 = 0 degrees, B = 65 degrees), the display depression angle D is 25 degrees, in the second state (R2 = +20 degrees, B = 85 degrees), the display depression angle D is 5 degrees, and in the third state (R2 = -20 degrees, B = 45 degrees), the display depression angle D is 45 degrees. In the second state, the screen of figurine 3A is tilted forward and closer to vertical, so the display depression angle D for the standing posture is reduced. In the third state, the screen is tilted backward and farther from vertical, so the display depression angle D for the standing posture is increased. As a result, regardless of the angle changed by angle adjustment mechanism 3700, when a user views figurine 3A at each tilt angle B, the standing posture of the character image within figurine 3A appears unchanged and constant, at 90 degrees (vertical) with respect to the horizontal axis H.

[0393] In addition, as in control example 1, the angle of the standing posture that remains unchanged regardless of the swing angle (constant posture angle, for example, 90 degrees from the horizontal and 0 degrees from the vertical) can be specified, selected, and set as the user's preferred angle.

[0394] Control example 2 shows a case where the invariant attitude angle is set to, for example, 65 degrees relative to the horizontal and -25 degrees relative to the vertical based on a user specification. To achieve this invariant attitude angle, the display depression angle is controlled to 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 invariant attitude angle is set to, for example, 115 degrees from the horizontal and +25 degrees from the vertical based on a user specification. To achieve this invariant attitude angle, the display depression angle is controlled to 50 degrees in the first state, 30 degrees in the second state, and 70 degrees in the third state.

[0396] 43 shows other control examples. Control example 4 is a case in which the display depression angle D within the standing figure 3A is kept constant at 25 degrees regardless of the head swing angle. In this case, as shown in the figure, in the first state the character is in an upright position (90 degrees) relative to the horizontal axis H, in the second state the character is in a forward-leaning position relative to the horizontal axis H, and in the third state the character is in a backward-leaning position relative to the horizontal axis H. Depending on the usage environment and situation, such as the user's viewpoint position and observation angle, these positions do not cause discomfort, so this control example can be adopted.

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

[0398] Note that when the swivel angle is changed by the angle adjustment mechanism 3700 as in the above example, the positions of the statue 3A and the character image in three-dimensional space change (see also FIG. 45 described below). The user can select and use the desired swivel angle and character image posture that best suits their usage situation, such as their preferred viewpoint position and observation angle.

[0399] The above control examples 1 to 4 show the control of the display depression angle D, but they can also be similarly applied to the control of the face display elevation angle E. That is, a configuration may be adopted in which the face display elevation angle E is controlled in accordance with the head swing angle.

[0400] Control example 5 is a variation of control example 1, and adds control for setting the face display elevation angle E to 45 degrees to the standing posture invariant control. Assuming that the user's observation angle is a depression angle of 45 degrees, the face display elevation angle E is set to the same 45 degrees in all of the first, second, and third states.

[0401] Control example 6 is an example in which the face display elevation angle E is changed depending on the state of the head swing angle. In a first state, the face display elevation angle E is 45 degrees, in a second state, the face display elevation angle E is 65 degrees, and in a third state, the face display elevation angle E is 25 degrees.

[0402] When the user sets the above-mentioned constant attitude angle or constant display depression angle, the angle can be selected, specified, and set on a user setting screen similar to that shown in Fig. 28. When specifying the constant attitude angle, the user may be able to directly select from values ​​such as 90 degrees, 95 degrees, and 85 degrees relative to the horizontal, or may be able to specify the angle in the form of the display depression angle in the first state (angle R1 = 0 degrees).

[0403] Similarly, even in a configuration that does not include an angle adjustment mechanism 3700 as in FIG. 35, the user can set the preferred standing posture angle (corresponding display depression angle, etc.).

[0404] [Control of Display Position and Size of Character Image] In Example 4, when displaying the character image in the floating image 3, in addition to controlling the display depression angle D and display elevation angle E according to the tilt angle as described above, the display position and size of the character image in the floating image 3 may 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, according to the display depression angle D of the character image's standing posture within the screen of the statue 3A. This ensures an even viewing angle / viewing range in the vertical direction, prevents the screen from being cut off, and realizes a display that is easier to see.

[0405] Fig. 44 shows an example of variable control of the display position and size of a character image in the floating in space image 3 according to the head swing angle. Fig. 44 shows a two-dimensional image corresponding to the display range 3R of the floating in space image 3. Example 1 is an example of an image of a character image when the user views the floating in space image 3 from the front (when viewed in the normal direction of the screen). The character image 4401 in this example is in a basic upright standing posture, and in terms of the shooting direction (depression angle) of the virtual camera described above (Fig. 24), it is an image capturing the front of the character's body. Point A is an example of the display position of the character image 4401, and is an example based on the feet.

[0406] Character video 4402 of Example 2 is an example of an image generated based on character video 4401 in the basic standing posture of Example 1, with the aforementioned virtual camera depression angle set to 65 degrees and display depression angle D set to 65 degrees, and corresponds to image 2504 in FIG. 25 . In Example 2, the image area of ​​character video 4402 is positioned closer to the bottom within the screen corresponding to display range 3R. Here, the character's display position is based on the feet, and an example of the display position is indicated by point B, etc. Space 4402a at the bottom of the screen is relatively small, while space 4402b at the top of the screen is relatively large and open. If the display depression angle D, etc., is changed while maintaining the size and proportions of the character's body, the size (e.g., vertical width) of the image area of ​​the character video within the screen changes.

[0407] When character video 4402 is displayed as in Example 2, that is, when the character image area is positioned toward the bottom of the screen, there is a risk that, depending on the user's observation angle, part of the character video may be invisible or difficult to view, as was shown in the problem described above in Figure 34 and elsewhere. With character video 4402 in Example 2, depending on the user's observation angle, the bottom of the screen may be cut off, making it difficult to view the character's feet, as if they were missing. Therefore, as a countermeasure, the display position of the character video on the screen may be adjusted.

[0408] Character video 4403 of 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 character video 4402 of Example 2. Specifically, by centering the image area of ​​the character video to position it near the center of the screen, point C, the display position of character video 4403, has moved upward from point B. The same is true when considering the display position of the character video as the center position of the image area (e.g., point Bb or point Cc), with point Cc being positioned near the center of the screen, above 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 bottom space 4403a within the screen is larger, so even if the top and bottom are cut off depending on the user's observation angle, as long as the cut is contained within the bottom space 4403a, loss of part of the character image is prevented or reduced. When the image of Example 3 is used, it is possible to ensure equal top and bottom viewing angles. Note that if priority is given to measures to prevent cut-off at the top of the screen, it is also possible to display an image that ensures a large top space 4402b, as in Example 2.

[0410] Furthermore, character video 4404 in Example 4 is a case where the size of the image area of ​​the character video is proportionally enlarged based on character video 4403 in Example 3. In this way, not only the display position but also the display size may be adjusted. Specifically, character video 4404 is enlarged 1.5 times from character video 4403 while maintaining centering. Point D is the display position based on the feet, and point Dd is the center position of the image area. In this case, the effect of measures to prevent clipping is reduced because the space above and below the screen is reduced, but instead, the character video can be viewed larger and more easily by the user. Adjustments to the display position and display size as in the above examples can be applied depending on the user's observation angle, etc.

[0411] Figure 45 is an explanatory diagram in which the state of the optical plate 150 and the statue 3A in Figures 38 and 39 are superimposed on the state in Figure 37. The til...

Claims

1. A floating image display device comprising: an image processing unit that processes images; a display unit that displays images processed by the image processing unit; and an optical system that generates a floating image based on the image displayed by the display unit, wherein the optical system has an optical plate including a retroreflective member, and the display unit has a display device that displays the image and a prism sheet arranged on the image light exit surface of the display device, wherein the image light from the display unit is incident on the optical plate at a first angle, and the image light retroreflected by the retroreflective member is emitted at the same angle as the first angle, forming the floating image at a position that is mirror-symmetrical with respect to the display device across the optical plate, and the display device is arranged below the optical plate at a first tilt angle, and the floating image is arranged above the optical plate at the same tilt angle as the first tilt angle, the image light emitted from the image light emission surface of the display device in a direction perpendicular to the surface is refracted by the prism sheet at a first refraction angle, and is incident on the optical plate at the first angle.

2. A floating-in-the-air image display device according to claim 1, wherein the refraction caused by the prism sheet is a refraction that widens the angle between the image light exit surface of the display unit and the optical plate compared to when the prism sheet is not provided and the image light emitted from the image light exit surface of the display unit in a direction perpendicular to the surface is incident on the optical plate at the first angle.

3. A floating-in-the-air image display device according to claim 1, wherein the floating-in-the-air image formed by the image light retroreflected by the retroreflective member has a brightness peak when observed at an observation angle corresponding to the first angle, the first angle being within the range of 45 degrees ± 10 degrees, the first tilt angle being within the range of 65 degrees ± 10 degrees, and the first refraction angle being within the range of 20 degrees ± 10 degrees.

4. A floating-in-the-air image display device according to claim 1, wherein when an object image is displayed within the screen of the floating-in-the-air image, the object image is displayed with its orientation within the screen at a predetermined display depression angle, thereby displaying the object image in space with its orientation at a predetermined attitude angle relative to the horizontal plane.

5. A floating-in-the-air image display device according to claim 4, wherein a plurality of postures of the object image corresponding to a plurality of display depression angles are prepared as preset image data and stored in memory, and the posture of the object image selected from the preset image data is displayed.

6. A floating-in-the-air image display device according to claim 4, wherein a plurality of orientations corresponding to a plurality of display depression angles are prepared as the orientation of the object image, and the orientation of the object image is switched to an orientation selected from the plurality of orientations in response to the operation of a physical button as a user operation input.

7. A floating-in-the-air image display device according to claim 4, wherein when the object image is displayed on the floating-in-the-air image, rendering processing is performed from a three-dimensional model to generate image data in which the orientation of the object image on the screen is set at the predetermined display depression angle.

8. A floating-in-the-air image display device according to claim 1, wherein, when an object image is displayed within the floating-in-the-air image screen, in a first control state, the object image is displayed within the screen at a predetermined display depression angle, and when an action is received from the user or a predetermined condition is satisfied, the control state is transitioned to a second control state, and in the second control state, at least a part of the object image is displayed at a predetermined display elevation angle so that it is looking up in the direction of an observation angle corresponding to the first angle.

9. A floating-in-the-air image display device according to claim 8, wherein a character image is displayed as the object image, and in the second control state, the face of the character image is displayed at the specified display elevation angle so as to look up in the direction of the observation angle corresponding to the first angle.

10. A floating image display device according to claim 1, wherein the optical plate is disposed on a horizontal plane or at an inclination angle within a range of 10 degrees ±5 degrees relative to the horizontal plane.

11. A floating image display device according to claim 10, further comprising a transparent plate disposed on a horizontal surface above the optical plate.

12. A floating-in-the-air image display device according to claim 1, wherein the housing of the floating-in-the-air image display device is provided with an angle adjustment mechanism for adjusting the angle of rotation in the forward and backward directions relative to the floating image, and the angle adjustment mechanism is used to rotate the housing in the forward and backward directions, thereby adjusting the angle of placement of the floating image.

13. A floating-in-the-air image display device according to claim 12, wherein when an object image is displayed within the floating-in-the-air image screen, the object image is displayed within the screen with its orientation at a predetermined display depression angle, thereby displaying the object image in space with its orientation at a predetermined attitude angle relative to the horizontal plane, and the display depression angle is set according to the angle at which the floating-in-the-air image is positioned by the angle adjustment mechanism.

14. A floating-in-the-air image display device according to claim 13, wherein the display depression angle is changed according to the angle at which the floating-in-the-air image is positioned by the angle adjustment mechanism, thereby controlling the attitude angle of the object image relative to the horizontal plane to remain constant.

15. A floating-in-the-air image display device according to claim 14, wherein a plurality of attitude angles are prepared for the object image, and the attitude angle of the object image can be selected from the plurality of attitude angles in response to a user's operational input.

16. A floating-in-the-air image display device according to claim 14, wherein, when the number of attitude angles of the object image is N and the number of changes in the display depression angle is M, M is a number greater than N.

17. A floating image display device according to claim 4, wherein when the object image is displayed within the floating image screen, the display depression angle of the object image within the screen is controlled, and at least one of the position and size of the object image within the screen is adjusted, thereby adjusting the space in the vertical direction within the screen where the object image is not placed.

18. A floating image display device according to claim 1, wherein the housing of the floating image display device comprises an upper housing that houses the optical system and the display unit, and a lower housing that is housed in a bottle holder.

19. A floating-in-the-air image display device according to claim 18, wherein the housing is provided with an angle adjustment mechanism for adjusting the angle of rotation in the forward and backward directions relative to the floating image, and the angle of placement of the floating image is adjusted by rotating the upper housing relative to the lower housing using the angle adjustment mechanism.

20. A floating image display device according to claim 18, wherein the lower housing is provided with a locking mechanism for fixing the lower housing within the bottle holder even when the diameter of the lower housing is smaller than the diameter of the bottle holder.

21. A floating image display device according to claim 4, comprising an imaging unit, which estimates the observation angle at which the user will observe the floating image based on the image captured by said imaging unit, and sets the display depression angle to match the estimated observation angle.

22. A floating image display device according to claim 8, comprising an imaging unit, which estimates the observation angle at which a user will observe the floating image based on an image captured by said imaging unit, and sets the display elevation angle to match the estimated observation angle.

23. A floating image display device comprising: an image processing unit that performs image processing; a display unit that displays an image processed by the image processing unit; and an optical system that generates a floating image based on the image displayed by the display unit, wherein the optical system has a polarization separation member and a retroreflective member with a λ / 4 plate on its incident surface, and the display unit has a display device that displays the image and a prism sheet arranged on the image light exit 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 and reflected by the polarization separation member, the reflected image light is retroreflected by the retroreflective member and converted into 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 exits at the same angle as the first angle, and the floating image is formed at a position that is mirror-symmetrical to the display device across the polarization separation member, The floating image is positioned at a first tilt angle relative to the polarization separation member on the side of the user's viewpoint, and the display device is positioned at an inclination angle equal to the first tilt angle on the opposite side of the polarization separation member from the floating image, and image light emitted from the image light emission surface of the display device in a direction perpendicular to the surface is refracted by the prism sheet at a first refraction angle, so that it is incident on the polarization separation member at the first angle.

24. A floating-in-the-air image display device according to claim 23, wherein the floating-in-the-air image formed by the image light retroreflected by the retroreflecting member has a brightness peak when observed at an observation angle corresponding to the first angle.

25. A floating-in-the-air image display device according to claim 23, wherein the first angle is within a range of 45 degrees ± 10 degrees, the first tilt angle is within a range of 65 degrees ± 10 degrees, and the first refraction angle is within a range of 20 degrees ± 10 degrees.

26. A floating-in-the-air image display device according to claim 23, further comprising an image light control sheet on the exit surface of the prism sheet for reducing the amount of refracted light rays other than those emitted from the prism sheet in the direction of the first refraction angle from reaching the polarization separation member and the retroreflective member.

27. A floating image display device according to claim 26, wherein the image light control sheet has a structure in which light-shielding portions and light-transmitting portions are repeatedly arranged, and the direction in which the light-shielding portions stand relative to the light-emitting surface of the prism sheet is an oblique angle corresponding to the direction of the first refraction angle.

28. A floating image display device according to claim 26, further comprising a parallel polarizing plate on the exit surface of the image light control sheet for correcting polarization disturbance caused by the prism sheet or the image light control sheet for the image light having the first polarization emitted from the display device.

29. A floating-in-the-air image display device according to claim 23, wherein the retroreflective member is disposed on the opposite side of the floating-in-the-air image from the polarization separating member at a predetermined tilt angle corresponding to the first angle, and the predetermined tilt angle is within the range of 45 degrees ± 10 degrees.

30. A floating-in-the-air image display device according to claim 23, wherein the housing of the floating-in-the-air image display device is provided with a retroreflection member angle adjustment mechanism for adjusting the angle of rotation of the retroreflection member.

31. A floating image display device according to claim 30, wherein the retroreflective member angle adjustment mechanism rotates the retroreflective member to set it at a predetermined tilt angle within the range of 45 degrees ± 10 degrees.

Images