Aerial floating image display apparatus

Abstract

Provided is a more preferable aerial floating image display apparatus. The present invention contributes to "3. Ensure healthy lives and promote well-being for all at all ages", "9. Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation", and "11. Make cities and human settlements inclusive, safe, resilient and sustainable" of the Sustainable Development Goals (SDGs). This aerial floating image display apparatus comprises: a light source device; a mask member that is disposed such that light emitted from the light source device enters therein in an oblique direction and that has a transparent part which has a prescribed shape and through which the entering light transmit; a retroreflection member that reflects the light having transmitted through the mask member and displays, in the air and by using the reflected light, an aerial floating image which is a real image; and an operation detector which detects an operation performed on the aerial floating image by a user.

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 problems, for example, the configuration described in the claims is adopted. The present application includes a plurality of means for solving the above problems, and one example thereof may be a floating-in-the-air image display device, comprising: a light source device; a mask member arranged so that light emitted from the light source device is incident at an oblique angle and having a transparent portion of a predetermined shape that transmits the incident light; a retroreflective member arranged parallel to the mask member, reflecting the light that has transmitted through the transparent portion and displaying a floating-in-the-air image that is a real image in the air using the reflected light; and an operation detector that detects an operation of the floating-in-the-air image by a user.

[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] 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 main part configuration and a retroreflector configuration of a space-floating image display device according to an embodiment of the present invention. FIG. 3 is a projection diagram of a retroreflector constituting a space-floating image display device according to an embodiment of the present invention. FIG. 4 is a top view of a retroreflector constituting a space-floating image display device according to an embodiment of the present invention. FIG. 5 is a perspective view showing a corner reflector constituting a retroreflector constituting a space-floating image display device according to an embodiment of the present invention. FIG. 6 is a top view of a corner reflector constituting a space-floating image display device according to an embodiment of the present invention. FIG. 7 is a side view of a corner reflector constituting a space-floating image display device according to an embodiment of the present invention. FIG. 8 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. 9 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. 10 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. 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. 12 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. 13 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. 14 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. 1 is a layout diagram showing a main part of a space-floating image display device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing the configuration of a display device according to an embodiment of the present invention. FIG. 3 is a cross-sectional view showing the configuration of a display device according to an embodiment of the present invention. FIG. 4 is an explanatory diagram for explaining light source diffusion characteristics of an image display device according to an embodiment of the present invention. FIG. 5 is an explanatory diagram for explaining diffusion characteristics of an image display device according to an embodiment of the present invention. FIG. 6 is a front view showing an example of a space-floating image display device according to an embodiment of the present invention. FIG. 7 is a top view showing an example of the layout of a spatial image display device according to an embodiment of the present invention. FIG. 8 is a side view schematically showing an example of the internal configuration of a spatial image display device according to an embodiment of the present invention. FIG. 9 is a diagram showing an example of a mask member according to an embodiment of the present invention. FIG. 10 is a diagram explaining an example of a space-floating image according to an embodiment of the present invention. FIG. 11 is a side view schematically showing an example of the internal configuration of a mask display unit according to an embodiment of the present invention. FIG. 12 is a diagram showing an example of an image light control sheet according to an embodiment of the present invention.FIG. 1 is a block 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 top view showing another example of the arrangement of a spatial image display device according to an embodiment of the present invention. FIG. 3 is a top view showing another example of the arrangement of a spatial image display device according to an embodiment of the present invention. FIG. 4 is a front view showing another example of the arrangement of a spatial floating image device according to an embodiment of the present invention. FIG. 5 is a top view schematically showing another example of a spatial image display device according to an embodiment of the present invention. FIG. 6 is a diagram showing another example of a mask member according to an embodiment of the present invention. FIG. 7 is a top view schematically showing another example of a spatial image display device according to an embodiment of the present invention. FIG. 8 is a side view schematically showing another example of the internal configuration of a spatial image display device according to an embodiment of the present invention. FIG. 9 is a side view schematically showing another example of the internal configuration of a spatial image display device according to an embodiment of the present invention. FIG. 10 is a front view explaining another example of a space-floating image display device according to an embodiment of the present invention.

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

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

[0011] According to the following embodiments, 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. Example 1

[0012] <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.

[0013] In addition, in a store or the like, a space is partitioned by a show window (also called "window glass") 105, which is a 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).

[0014] 1, the inside of the window glass 105 (inside the store) is shown in the depth direction, and the outside (for example, the sidewalk) is shown in the foreground. On the other hand, by providing a means for reflecting specific polarized waves 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.

[0015] <Configuration example of optical system of space-floating image display device> A configuration example of an optical system of a space-floating image display device will be described with reference to Fig. 2A. The optical system of Fig. 2A is an optical system that uses a retroreflector 5. Below, the configuration example of the optical system will be described in more detail with reference to Figs. 2A to 2F.

[0016] 2A 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 for emitting 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 for generating light.

[0017] 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°.

[0018] 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.

[0019] 2B, 2C, 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.

[0020] 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. 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 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.

[0021] An example of the configuration of the retroreflector 5 will be described using Figures 2B and 2C. The retroreflector 5 has a configuration in which a plurality of corner reflectors 9040 are arranged in an array on the surface of a transparent member 50. 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 2D, 2E, and 2F. 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.

[0022] 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.

[0023] 2D, 2E, and 2F, 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.

[0024] 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).

[0025] 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.

[0026] 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.

[0027] 2A, the retroreflector 5 has retroreflection properties in two axes and specular reflection in the other axis. 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 toward the side of the retroreflector 5 opposite to the side 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.

[0028] 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.

[0029] 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.

[0030] The resolution of the spatially floating image formed by the light beams from the video output unit 10 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 2B and 2C. 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 spatially floating image will be equivalent to 300 μm. As a result, the effective resolution of the spatially floating image will be reduced to about one-third.

[0031] 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.

[0032] 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.

[0033] 2A, the image light emitted from the display device 1 may be in any polarization state, either S-polarized or P-polarized.

[0034] As described above, the optical system of FIG. 2A can form a more suitable floating image in space.

[0035] According to the optical system of FIG. 2A described above, it is possible to provide a brighter and higher quality floating image in space.

[0036] <<Block diagram of the internal configuration of the space floating image display device>>

[0037] Next, a description will be given of a block diagram of the internal configuration of the space-floating image display device 1000. Fig. 3 is a block diagram showing an example of the internal configuration of the space-floating image display device 1000.

[0038] 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.

[0039] 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.

[0040] The retroreflecting portion 1101 in Fig. 3 corresponds to the retroreflector 5 in Fig. 2A. The retroreflecting portion 1101 retroreflects light modulated by the image display portion 1102. Of the light reflected from the retroreflecting portion 1101, the light output to the outside of the space-floating image display device 1000 forms the space-floating image 3.

[0041] The image display unit 1102 in Fig. 3 corresponds to the liquid crystal display panel 11 in Fig. 2A. The light source 1105 in Fig. 3 corresponds to the light source device 13 in Fig. 2A. 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.

[0042] The video display unit 1102 is a display unit that generates a video by modulating transmitted light based on a video signal input under the control of a video control unit 1160 (described later). The video display unit 1102 corresponds to the liquid crystal display panel 11 in FIG. 2A. For example, a transmissive liquid crystal panel is used as the video display unit 1102. Alternatively, for example, a reflective liquid crystal panel that modulates reflected light or a DMD (Digital Micromirror Device: registered trademark) panel may be used as the video display unit 1102.

[0043] The light source 1105 generates light for the image display unit 1102 and is a solid-state light source such as an LED light source or a laser light source. The power source 1106 converts AC current input from the outside via the external power input interface 1111 into DC current and supplies power to the light source 1105. The power source 1106 also supplies the necessary DC current to each component within the space-floating image display device 1000. The secondary battery 1112 stores the power supplied from the power source 1106. The secondary battery 1112 also supplies power to the light source 1105 and other components requiring power via the external power input interface 1111 when power is not supplied from the outside. In other words, when the space-floating image display device 1000 is equipped with the secondary battery 1112, the user can use the space-floating image display device 1000 even when power is not supplied from the outside.

[0044] 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.

[0045] The aerial operation detection sensor 1351 is a sensor for detecting an operation of the floating-in-space image 3 by the finger of the user 230. The aerial operation detection sensor 1351 senses, for example, an area that overlaps with the entire display area of ​​the floating-in-space image 3. Note that the aerial operation detection sensor 1351 may only sense an area that overlaps with at least a portion of the display area of ​​the floating-in-space image 3.

[0046] 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.

[0047] The mid-air operation detection sensor 1351 only needs to be capable of sensing to detect touch operations by the user 230 on objects displayed as the floating-in-space image 3. Such sensing can be performed using existing technology.

[0048] The aerial operation detection unit 1350 acquires a sensing signal from the aerial operation detection sensor 1351, and determines whether or not the finger of the user 230 has made contact with an object in the floating-in-space image 3 based on the sensing signal, and calculates the position (contact position) where the finger of the user 230 has made contact with the object. The aerial operation detection unit 1350 is configured with a circuit such as an FPGA (Field Programmable Gate Array), for example. Furthermore, some of the functions of the aerial operation detection unit 1350 may be realized by software using a spatial operation detection program executed by the control unit 1110, for example.

[0049] 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.

[0050] Furthermore, the aerial operation detection sensor 1351 and the aerial operation detection unit 1350 may be provided separately. This makes it possible to build a system in which the space-floating image display device 1000, which does not have an aerial operation detection function, is used as the main body, and only the aerial operation detection function can be added as an option. Furthermore, a configuration in which only the aerial operation detection sensor 1351 is provided separately, and the aerial operation detection unit 1350 is built into the space-floating image display device 1000 may be used. In cases 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, a configuration in which only the aerial operation detection sensor 1351 is provided separately is advantageous.

[0051] The imaging unit 1180 is a camera with an image sensor, and captures images of the space near the floating-in-space image 3 and / or the face, arms, fingers, etc. of the user 230. A plurality of imaging units 1180 may be provided. By using a plurality of imaging units 1180, or by using an imaging unit with a depth sensor, the mid-air operation detection unit 1350 can be assisted in detecting the touch operation of the floating-in-space image 3 by the user 230. The imaging unit 1180 may be provided separately from the floating-in-space image display device 1000. When the imaging unit 1180 is provided separately from the floating-in-space image display device 1000, it is sufficient to configure it so that an imaging signal can be transmitted to the floating-in-space image display device 1000 via a wired or wireless communication connection path, etc.

[0052] For example, if the aerial operation detection sensor 1351 is configured as an object intrusion sensor that targets a plane (intrusion detection plane) including the display surface of the spatial floating image 3 and detects whether or not an object has intruded into this intrusion detection plane, the aerial operation detection sensor 1351 may not be able to detect information such as how far an object 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.

[0053] In such a case, the distance between the object and the intrusion detection plane can be calculated by using information such as object depth calculation information based on the images captured by the multiple image capturing units 1180 and object depth information from the depth sensor. These pieces of information and various other information such as the distance between the object and the intrusion detection plane are then used for various display controls for the floating in space image 3.

[0054] Furthermore, without using the aerial operation detection sensor 1351 , the aerial operation detection unit 1350 may detect a touch operation on the floating-in-space image 3 by the user 230 based on the captured image by the imaging unit 1180 .

[0055] Furthermore, the imaging unit 1180 may capture an image of the face of the user 230 operating the space-floating image 3, and the control unit 1110 may perform an identification process for the user 230. Furthermore, in order to determine whether or not there is another person standing around or behind the user 230 operating the space-floating image 3 and peeking at the operation of the user 230 on the space-floating image 3, the imaging unit 1180 may capture an image of the user 230 operating the space-floating image 3 and a range including the area surrounding the user 230.

[0056] 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 aerial operation (touch operation) by the user 230. Apart from the above-mentioned user 230 who touches the space floating image 3, the operation input unit 1107 may also be used by, for example, an administrator to operate the space floating image display device 1000.

[0057] The video signal input unit 1131 is connected to an external video output device and inputs video data. Various digital video input interfaces are possible for the video signal input unit 1131. For example, the video signal input unit 1131 may be configured as a video input interface conforming to the HDMI (registered trademark) standard (High-Definition Multimedia Interface), a video input interface conforming to the DVI (Digital Visual Interface) standard, or a video input interface conforming to the DisplayPort standard.

[0058] Alternatively, an analog video input interface such as analog RGB or composite video may be provided. The audio signal input unit 1133 connects to an external audio output device and inputs audio data. The audio signal input unit 1133 may be configured 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. The audio output unit 1140 is capable of outputting audio based on the audio data input to the audio signal input unit 1133. The audio output unit 1140 may be configured as a speaker.

[0059] The audio output unit 1140 may also output built-in operation sounds or error warning sounds. Alternatively, the audio output unit 1140 may be configured to output a digital signal to an external device, like the Audio Return Channel function defined in the HDMI standard. 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, described later, may perform voice recognition processing on the generated audio signal to obtain text information from the audio signal.

[0060] 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 and layout information for objects to be operated by user operations, etc. The memory 1109 stores image data to be displayed as the space floating image 3, data for controlling the device, etc.

[0061] The control unit 1110 controls the operation of each connected unit. In addition, the control unit 1110 may cooperate with a program stored in the memory 1109 to perform calculations based on information acquired from each unit in the space floating image display device 1000.

[0062] 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.

[0063] The removable media interface 1134 is an interface for connecting a removable recording medium (removable media). The removable recording medium (removable media) may be composed of a semiconductor device memory such as a solid state drive (SSD), a magnetic recording medium recording device such as a hard disk drive (HDD), or an optical recording medium such as an optical disk. The removable media interface 1134 can read various information such as video data, image data, and audio data recorded on the removable recording medium. The video data, image data, etc. recorded on the removable recording medium are output as the floating image 3 via the video display unit 1102 and the retroreflection unit 1101.

[0064] 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.

[0065] The video data, image data, etc. recorded in the storage unit 1170 are output as the space floating image 3 via the video display unit 1102 and the retroreflection unit 1101. The video data, image data, etc. of display icons, objects for the user to operate, etc., displayed as the space floating image 3, are also recorded in the storage unit 1170.

[0066] Layout information of display icons, objects, etc. displayed as the spatial floating image 3, and various metadata information related to the objects, etc. are also recorded in the storage unit 1170. The audio data recorded in the storage unit 1170 is output as audio from the audio output unit 1140, for example.

[0067] The video control unit 1160 performs various controls related to the video signal input to the video display unit 1102. The video control unit 1160 may be 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 an image processing unit. The video control unit 1160 controls video switching, 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, for example.

[0068] 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.

[0069] 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.

[0070] Furthermore, the video control unit 1160 may perform special effect video processing or the like on the video signal input to the video display unit 1102 to assist the aerial operation (touch operation) of the user 230. The special effect video processing is performed based on, for example, the detection result of the touch operation of the user 230 by the aerial operation detection unit 1350 or the image of the user 230 captured by the imaging unit 1180.

[0071] 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.

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

[0073] <Configuration Example of 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 4C will be described. Note that in each of the examples of Figs. 4A to 4C, the thick line surrounding the space-floating image display device 1000 indicates an example of the housing structure of the space-floating image display device 1000.

[0074] FIG. 4A is a diagram showing an example of the configuration of a space-floating image display device. The space-floating image display device 1000 of FIG. 4A is a space-floating image display device that employs the optical system of FIG. 2A. An image is formed in the air as a space-floating image 3 by image light transmitted through a transparent member 100. Furthermore, the operation of the space-floating image 3 by the user's finger 9004 can be detected using sensing light from an aerial operation detection sensor 1351 disposed on the far side of the transparent member 100 as viewed from the user. The x-direction is the left-right direction as viewed from the user, the y-direction is the front-back direction (depth direction) as viewed from the user, and the z-direction is the up-down direction (vertical direction). The definitions of the x-direction, y-direction, and z-direction are the same in each of the figures following FIG. 4A , and therefore repeated explanations will be omitted.

[0075] In the example of the floating-in-space image display device that employs the optical system of FIG. 2A , the floating-in-space image 3 is formed in front of the transparent member 100, and the operation of the floating-in-space image 3 by the user's finger can be detected using the sensing light of the mid-air operation detection sensor 1351 that is located on the back side of the transparent member 100 as seen from the user.

[0076] Next, Fig. 4B is a diagram showing an example of the configuration of a space-floating image display device. Fig. 4B is a diagram showing the configuration of the internal optical system of the space-floating image display device 1000 of Fig. 4A. 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 horizontally so that the surface on which the space-floating image 3 is formed faces upward.

[0077] 4B, 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.

[0078] In addition, in FIG. 4B, the display device 1 and the spatial floating image 3 are in a plane-symmetrical relationship with respect to the surface of the retroreflector 5 .

[0079] 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. 2A. The space-floating image display device 1000 shown in FIG. 4C 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. 4C, 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. When the mid-air operation detection sensor 1351 is installed as shown in FIG. 4C, it is possible to detect the operation of the space-floating image 3 by the user 230's finger. 4C , the aerial operation detection sensor 1351 senses the finger of the user 230 from above, and can utilize the reflection of sensing light by the nail of the user 230 for touch detection. Generally, a nail has a higher reflectivity than the pad of a finger, and therefore, configuring the aerial operation detection sensor 1351 in this way can improve the accuracy of touch detection.

[0080] According to the configuration of the space floating image display device of FIGS. 4A to 4C, it is possible to realize a user-friendly space floating image display device using the optical system of FIG. 2A.

[0081] <Display Device> Next, the display device 1 of this embodiment will be described with reference to the drawings. The display device 1 of this embodiment includes an image display element 11 (liquid crystal display panel) and a light source device 13 that constitutes the light source of the image display element 11. Fig. 5 shows the light source device 13 together with the liquid crystal display panel as an exploded perspective view.

[0082] As shown by arrow 30 in Figure 5, this liquid crystal display panel (image display element 11) receives an illumination light beam from light source device 13, which is a backlight device, that has narrow-angle diffusion characteristics, i.e., has strong directivity (linearity) and characteristics similar to laser light with a polarization plane aligned in one direction. The liquid crystal display panel (image display element 11) modulates the received illumination light beam in accordance with an input video signal. The modulated image light is reflected by retroreflector 2 and passes through transparent member 100 to form a real image, a floating image in space (see Figure 1).

[0083] 5 also shows a configuration including a liquid crystal display panel 11 constituting the display device 1, a light redirection panel 54 for controlling the directional characteristics of the light beam emitted from the light source device 13, and, if necessary, a narrow-angle diffuser (not shown). Specifically, polarizing plates are provided on both sides of the liquid crystal display panel 11, and image light of a specific polarization is emitted with its intensity modulated by a video signal (see arrow 30 in FIG. 5). This allows 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, where it is reflected by the retroreflector 2 and transmitted to the eyes of a monitor outside the store (space), forming a floating image 3. A protective cover 50 (see FIGS. 6 and 7) may be provided on the surface of the light redirection panel 54.

[0084] <Display Device Example 1> FIG. 6 shows an example of a specific configuration of the display device 1. In FIG. 6, a liquid crystal display panel 11 and a light direction conversion panel 54 are disposed on the light source device 13 shown in FIG. 5. The light source device 13 is configured on a case shown in FIG. 5, formed of, for example, plastic, and contains LED elements 201 and a light guide 203 therein. 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 by multiple total reflections during propagation within 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, LED (Light Emitting Diode) elements 201, which are semiconductor light sources, and an LED board 202 on which their control circuits are mounted are attached to one side of the case of the light source device 13 (the left end surface in this example). A heat sink, which is a member for cooling the heat generated by the LED elements and the control circuit, may be attached to the outer surface of the LED board 202 .

[0085] Furthermore, a frame (not shown) for the liquid crystal display panel is attached to the top surface of the case of the light source device 13. The frame includes the liquid crystal display panel 11, which is attached to the frame, and a flexible printed circuit (FPC) (not shown) electrically connected to the liquid crystal display panel 11. That is, the liquid crystal display panel 11, which is an image display element, generates a display image by modulating the intensity of transmitted light in conjunction with the LED elements 201, which are solid-state light sources, based on a control signal from a control circuit (image control unit 1160 in FIG. 3 ) constituting the electronic device. The generated image light has a narrow diffusion angle and contains only specific polarization components, resulting in a novel image display device similar to a surface-emitting laser image source driven by a video signal. Currently, it is technically and safety-wise impossible to obtain a laser beam of the same size as the image obtained by the display device 1 described above using a laser device. Therefore, in this embodiment, light similar to the surface-emitting laser image light described above is obtained from a beam of light from a general light source, for example, an LED element.

[0086] Next, the configuration of the optical system housed in the case of the light source device 13 will be described in detail with reference to FIG. 7 as well as FIG.

[0087] 6 and 7 are cross-sectional views, and only one of the LED elements 201 constituting the light source is shown, and this light is converted into approximately collimated light by the shape of the light-receiving end surface 203a of the light guide 203. For this reason, the light-receiving portion on the end surface of the light guide and the LED element are attached while maintaining a predetermined positional relationship.

[0088] 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, and the top of the light guide 203 has a concave portion with a convex portion (i.e., a convex lens surface) formed in the center, and the center of the flat portion has a convex lens surface (or a concave lens surface) that protrudes outward (not shown). The outer shape of the light-receiving portion of the light guide to which the LED element 201 is attached is a parabolic shape that forms a cone-shaped outer periphery, and is set within an angle range that allows total reflection of the light emitted from the LED element toward the periphery within the parabolic shape, or a reflective surface is formed.

[0089] On the other hand, the LED elements 201 are arranged at predetermined positions on the surface of the circuit board, that is, the LED substrate 202. The LED substrate 202 is arranged and fixed to the LED collimator (light-receiving end surface 203 a) so that the LED elements 201 on the surface are positioned in the center of the recessed portion described above.

[0090] 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.

[0091] 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 end surface, which is then guided inside the light guide 203 as shown by the arrow (in a direction parallel to the drawing), and emitted by the light beam direction conversion means 204 toward the liquid crystal display panel 11, which is disposed approximately parallel to the light guide 203 (in a direction perpendicular to the front of the drawing). The uniformity of the light beam incident on the liquid crystal display panel 11 can be controlled by optimizing the distribution (density) of the light beam direction conversion means 204 depending on the shape inside or on the surface of the light guide.

[0092] The light beam direction conversion means 204 described above emits the light beam propagated inside the light guide toward the liquid crystal display panel 11 (in a direction perpendicular to the front of the drawing) that is disposed substantially parallel to the light guide 203, by changing the shape of the surface of the light guide or by providing a portion with a different refractive index inside the light guide. In this case, when the liquid crystal display panel 11 is faced directly at the center of the screen and the viewpoint is positioned at the same position as the diagonal dimension of the screen, if the relative brightness ratio between the center of the screen and the periphery of the screen is 20% or more, there is no practical problem, and if it exceeds 30%, it will be an even better characteristic.

[0093] 6 is a cross-sectional layout diagram illustrating the configuration and operation of the light source of this embodiment that performs polarization conversion in light source device 13 including the above-mentioned light guide 203 and LED element 201. In Fig. 6, light source device 13 is composed of light guide 203 formed of, for example, plastic or the like and having light beam direction conversion means 204 on its surface or inside, LED element 201 as a light source, reflective sheet 205, retardation plate 206, lenticular lens, etc., and on the upper surface thereof is attached liquid crystal display panel 11 that has polarizing plates on the light source light entrance surface and the image light exit surface.

[0094] In addition, a film or sheet-like reflective polarizing plate 49 is provided on the light source light incident surface (bottom surface in the figure) of the liquid crystal display panel 11 corresponding to the light source device 13, selectively reflecting one 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 (bottom surface in the figure) of the light guide 203 and directed toward the liquid crystal display panel 11. Therefore, a retardation plate (λ / 4 plate) is provided between the reflective sheet 205 and the light guide 203 or between the light guide 203 and the reflective polarizing plate 49, and the reflected light beam is reflected by the reflective sheet 205 and passes through it twice to convert the reflected light beam from P polarized light to S polarized light, thereby improving the utilization efficiency of the light source light as image light. The image light beam, the light intensity of which is modulated by a video signal in the liquid crystal display panel 11 (arrow 213 in Figure 6), enters the retroreflector 2. After reflection by the retroreflector 2, a real image, a floating image in space, can be obtained.

[0095] 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 an LED element 201, similar to Fig. 6. The light source device 13 is similarly configured with 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 is attached to the top surface of the light source device 13 as an image display element, and the panel has polarizing plates on the light source light entrance surface and the image light exit surface.

[0096] A film or sheet-like reflective polarizing plate 49 is provided on the light source light incidence surface (bottom surface in the figure) of the liquid crystal display panel 11 corresponding to the light source device 13, selectively reflecting one polarized wave (e.g., S wave) 211 of the natural light beam 210 emitted from the LED element 201. That is, in the example of FIG. 7 , the selective reflection characteristics of the reflective polarizing plate 49 differ from those in FIG. 7 . The reflected light is reflected by a reflective sheet 205 provided on one surface (bottom surface in the figure) of the light guide 203 and returns to the liquid crystal display panel 11. A retardation plate (λ / 4 plate) is provided between the reflective sheet 205 and the light guide 203 or between the light guide 203 and the reflective polarizing plate 49, and the reflected light beam is reflected by the reflective sheet 205 and passes through it twice, converting the reflected light beam from S-polarized light to P-polarized light, thereby improving the utilization efficiency of the light source light as image light. The image light beam intensity-modulated by the image signal in the liquid crystal display panel 11 (arrow 214 in FIG. 7 ) enters the retroreflector 2. After reflection by the retroreflector 2, a real image, a floating image in space, can be obtained.

[0097] In the light source devices shown in Figures 6 and 7, in addition to the function of the polarizer provided on the light incident surface of the corresponding liquid crystal display panel 11, the reflective polarizer reflects the polarized light component on one side. 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. 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.

[0098] <Display Device Example 2> Figure 8 shows another example of the specific configuration of the display device 1. This light source device 13 is configured by housing LEDs, a collimator, a composite diffusion block, a light guide, etc., in a case made of, for example, plastic, and has a liquid crystal display panel 11 attached to its upper surface. Also, an LED board on which LED (Light Emitting Diode) elements 14a and 14b, which are semiconductor light sources, and their control circuits are mounted are attached to one side of the case of the light source device 13, and a heat sink 103, which is a member for cooling heat generated by the LED elements and the control circuit, is attached to the outer surface of the LED board.

[0099] The liquid crystal display panel frame attached to the top surface of the case is configured to have attached thereto the liquid crystal display panel 11 attached to the frame, and further to have attached thereto an FPC (Flexible Printed Circuits) 403 electrically connected to the liquid crystal display panel 11. That is, the liquid crystal display panel 11, which is a liquid crystal display element, generates a display image by modulating the intensity of transmitted light together with the LED elements 14a and 14b, which are solid-state light sources, based on a control signal from a control circuit (not shown here) that constitutes the electronic device.

[0100] <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 an LED into a substantially parallel beam by a collimator 18, and reflects the parallel beam toward the liquid crystal display panel 11 by the reflective surface of a reflective light guide 304. The reflected light is incident on a reflective polarizer 49 disposed between the liquid crystal display panel 11 and the reflective light guide 304. The reflective polarizer 49 transmits light of a specific polarization (e.g., P-polarized light) and causes the transmitted polarized light to be incident on the liquid crystal display panel 11. Here, light 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.

[0101] 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.

[0102] 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).

[0103] As a result, the light from the LED is aligned to a specific polarization (for example, P polarization), enters the liquid crystal display panel 11, and is brightness-modulated in accordance with the video signal to display an image on the panel surface. As in the above example, multiple LEDs that make up the light source are shown (however, because this is a vertical cross section, only one is shown in Figure 9), and these are attached at predetermined positions relative to the collimator 18.

[0104] 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 102). The collimator 18 may have a convex lens surface (or a concave lens surface) protruding outward in the center of the flat surface (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 toward the periphery, or a reflective surface is formed therein.

[0105] The LEDs are arranged at predetermined positions on the surface of the circuit board, that is, the LED board 102. The LED board 102 is arranged and fixed to the collimator 18 so that the LEDs on the surface are positioned at the center of the apex of the convex cone shape (or in the recess if the apex has a recess).

[0106] With this configuration, the collimator 18 focuses light emitted from the LED, particularly light emitted from the central portion, into parallel light by the convex lens surface that forms the outer shape of the collimator 18. Light emitted from other portions toward the periphery is reflected by the parabolic surface that forms the outer peripheral surface of the conical shape of the collimator 18, and is similarly focused into parallel light. In other words, the collimator 18, which has a convex lens in its center and a parabolic surface formed on its periphery, makes it possible to extract almost all of the light generated by the LED as parallel light, thereby improving the utilization efficiency of the generated light.

[0107] 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 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. Adjusting the surface roughness of the reflective surface of the reflective light guide 304 and the surface roughness of the reflector 271 for each design can improve the uniformity of the light incident on the liquid crystal display panel 11.

[0108] 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.

[0109] <Display Device Example 4> Another example (Display Device Example 4) of the configuration of an optical system such as a light source device of a display device will be described with reference to Fig. 10. This is 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 (optical sheet 207A and optical sheet 207B) that convert diffusion characteristics in the vertical and horizontal directions of the drawing (front-to-back directions not shown in the drawing) are used on the light emission side of collimator 18, and light from collimator 18 is made to enter between the two optical sheets (diffusion sheets).

[0110] 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 on the front and back surfaces of the single optical sheet. Alternatively, multiple diffusion sheets may be used to share the functions. In the example of FIG. 10 , the reflection and diffusion characteristics due to the front and back shapes of optical sheets 207A and 207B can be optimally designed using the number of LEDs, the divergence angle from LED substrate (optical element) 102, and the optical specifications of collimator 18 as design parameters so that the surface density of the light beam emitted from the liquid crystal display panel 11 is uniform. In other words, the diffusion characteristics are adjusted by the surface shapes of multiple diffusion sheets instead of light guides.

[0111] 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, 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, 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.

[0112] 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.

[0113] 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 on the X-axis in FIG. 12(a)) and the vertical direction of the screen (shown on the Y-axis in FIG. 12(b)). In contrast, the diffusion characteristics of the light beam emitted from the liquid crystal display panel 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 (angle of 0 degrees) is set to 13 degrees, this is 1 / 5 of the 62 degrees 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 more than 50 times higher.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] <Example 2> Fig. 13 is a front view showing a schematic configuration of a space-floating image display device of Example 2, and Fig. 14 is a top view showing a schematic internal configuration of the space-floating image display device of Example 2. Fig. 15 is a diagram showing a schematic internal configuration of the space-floating image display device of Example 2. Fig. 16 is a diagram showing a mask member according to Example 2, and Fig. 17 is a diagram explaining a space-floating image according to Example 2. Fig. 18 is a diagram showing a schematic internal configuration of a mask display unit according to Example 2. Fig. 19 is a diagram showing a schematic image light control sheet according to Example 2.

[0121] As shown in FIGS. 13 to 15 , the space-floating image display device 1000A according to the second embodiment displays a space-floating image 3, which is a still image. As an example, the space-floating image display device 1000A displays three still images of push buttons, namely, an "A" button, a "B" button, and a "C" button, as the space-floating image 3. In other words, the space-floating image display device 1000A functions as an air button operation panel having a plurality of air buttons that are displayed as space-floating images 3 and operated by the user 230. The number of space-floating images 3 displayed by the space-floating image display device 1000A is not particularly limited, and may be four or more, or may be two or less. In other words, the space-floating image display device 1000A may include three or more aerial image display devices 1300 as shown in FIG. 13 , or may include only one aerial image display device 1300.

[0122] 4C, the space-floating image display device 1000A according to the second embodiment 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 1000A (facing the user 230). That is, the space-floating image display device 1000A is installed vertically so that the transparent member 100 faces the user 230.

[0123] In the space-floating image display device 1000A, as in the example of FIG. 4C, the image light reflected by the retroreflector 5 travels diagonally upward, and a space-floating image 3 is formed on the user 230 side of the transparent member 100. However, in the space-floating image display device 1000A, the space-floating image 3 is formed along the vertical direction (z direction). In other words, the space-floating image 3 is formed to face the horizontal direction (y direction). Incidentally, in the space-floating image display device 1000 shown in FIG. 4C, the space-floating image 3 is formed to face in a direction intersecting the y direction (diagonally upward). Of course, in the space-floating image display device 1000A of Example 2, the space-floating image 3 may also face diagonally upward.

[0124] Furthermore, the space-floating image display device 1000A is installed so that the space-floating image 3 is formed at a position lower than the eye height of the user 230. In other words, the space-floating image display device 1000A is installed, for example, on the floor surface so that the line of sight 230E of the user 230 looking at the space-floating image 3 while standing is directed diagonally downward. As described above, the light that forms the space-floating image 3 travels diagonally upward, so by forming the space-floating image 3 at such a height, the user 230 can easily view the space-floating image 3 and can also easily operate it with their fingers.

[0125] The internal structure of the space-floating image display device 1000A will be described in more detail below. The space-floating image display device 1000A includes three space-image display devices (also referred to as space-image display units) 1300 that form the space-floating images 3. Each space-floating image display device 1300 forms one space-floating image 3. In this example, each space-floating image display device 1300 displays still images of buttons "A," "B," and "C" as the space-floating images 3. Note that the space-floating image display device 1300 may be configured to form multiple space-floating images 3.

[0126] Each spatial image display device 1300 is disposed opposite the transparent member 100, and forms a spatially floating image 3 outside the transparent member 100. These spatial image display devices 1300 are disposed in a row along the left-right direction (x direction) of the spatially floating image display device 1000A. Therefore, each spatially floating image 3 is formed in a row along the x direction. In other words, the chief ray L1 of the light (image light) forming each spatially floating image 3 travels parallel to the y-z plane.

[0127] The transparent member 100 is provided to cover the opening of the housing 1190, and functions as a protective plate that protects the devices disposed inside the housing 1190. In this example, the transparent member 100 is provided independently corresponding to each aerial image display device 1300. However, the transparent member 100 may be provided in common to the three aerial image display devices 1300.

[0128] 15 , each aerial image display device 1300 includes the above-mentioned retroreflector 5 and a mask display unit 1310. The mask display unit 1310 includes a mask member 1320 and a light source device 1330. Furthermore, each aerial image display device 1300 includes an image light control sheet 335, an aerial operation detection sensor 1351 as an aerial operation detector, and the like. The retroreflector 5 and the mask member 1320 are arranged substantially parallel to the transparent member 100 along the vertical direction (z direction). Therefore, the floating image 3 is formed near the outside of the transparent member 100 along the vertical direction (z direction).

[0129] The retroreflector 5 is disposed close to and parallel to the transparent member 100. In this embodiment, the retroreflector 5 is disposed with a gap between it and the transparent member 100, but it may also be in contact with the transparent member 100. Furthermore, the retroreflector 5 and the transparent member 100 do not necessarily have to be disposed parallel to each other. Note that the configuration of the retroreflector 5 itself is the same as in Example 1, and therefore a description thereof will be omitted here.

[0130] The mask display unit 1310 transmits light emitted by a light source device 1330 through a mask member 1320, thereby outputting it as image light of any shape. As shown in an example in FIG. 16 , the mask member 1320 includes a transmissive portion 1321 of a predetermined shape through which light incident from the light source device 1330 passes, and a low-transmissive portion 1322 that has a lower light transmittance than the transmissive portion 1321. In the example shown in FIG. 16 , the circular white portion is the transmissive portion 1321. The letter "A" is the low-transmissive portion 1322, which has a lower transmittance than the transmissive portion 1321 but transmits light. The black portion surrounding the transmissive portion 1321 is a non-transmissive portion 1323, which barely transmits light incident from the light source device 1330.

[0131] The non-transmitting portion 1323 is a portion that has a lower light transmittance than the transmitting portion 1321, and is included in the low-transmitting portion 1322. In this embodiment, the portion of the alphabet "A" is the low-transmitting portion 1322 that transmits light, but this portion may also be the non-transmitting portion 1323 that does not transmit light.

[0132] This mask member 1320 is formed by reducing the transmittance of a portion of a base substrate made of a transparent material. For example, the mask member 1320 is formed by reducing the transmittance of the base substrate except for an area that will become the transmissive portion 1321. The material of the base substrate is not particularly limited as long as it is a transparent material, but for example, glass, plastic, etc. are preferably used.

[0133] The method for reducing the transmittance of the base substrate, that is, the method for forming the mask member 1320, is not particularly limited, and examples thereof include the following methods. One example is a method of selectively applying a coating that absorbs or reflects visible light to the surface of the base substrate. In this method, the uncoated portions of the base substrate become the transmissive portions 1321, and the coated portions become the low-transmissive portions 1322. Alternatively, for example, the portions of the base substrate that will become the low-transmissive portions 1322 may be printed with a light-absorbing ink. Furthermore, the non-transmissive portions 1323 may be formed, for example, by adhering a thin plate that does not transmit light, such as a metal plate, to the surface of the base substrate.

[0134] The light (image light) that has passed through the mask member 1320 is incident on the retroreflector 5, and as shown in Fig. 17, a still image of a circular "A" button is displayed as a floating image 3. In the floating image 3 shown in Fig. 17, the first area A1, which is the white portion, is formed by light that has passed through the transmissive portion 1321 of the mask member 1320. The second area A2 corresponding to the alphabet "A" is formed by light that has passed through the low-transmissive portion 1322 of the mask member 1320, and is darker than the first area A1. The black third area A3 in the figure is an area where light is blocked by the non-transmissive portion 1323 of the mask member 1320, and in reality, the background is visible.

[0135] In this way, in the spatial image display device 1300 provided in the space-floating image display device 1000A, the image light emitted from the mask display unit 1310 is reflected by the retroreflector 5, and a still image of the push button operated by the finger of the user 230 is displayed on the outside of the transparent member 100 as the space-floating image 3. Also, as described above, the space-floating image display device 1000A has three spatial image display devices 1300, and three still images of the "A" button, "B" button, and "C" button are displayed as the space-floating image 3 (see FIG. 13).

[0136] As shown in FIG. 18, the light source device 1330 that emits light toward the mask member 1320 includes a light source 1331, a light guide 1332, and an optical element 1333 arranged between the light source 1331 and the light guide 1332.

[0137] The light source 1331 generates light to form the floating image 3, which is a still image, and may be, for example, a lamp, a monochromatic LED light source, a multicolor LED light source, a laser light source, or any other light source that emits visible light.

[0138] The light guide 1332 is formed, for example, by a reflecting mirror, and guides the light generated by the light source 1331 so that the light is incident on the mask member 1320 obliquely downward. In other words, the light guide 1332 guides the light generated by the light source 1331 so that the light is incident on the mask member 1320 obliquely downward. The light guide 1332 is disposed at an angle relative to the direction of incidence of light into the light guide 1332, which in this example is the vertical direction (z direction). Specifically, the light guide 1332 is disposed at an angle relative to the vertical direction (z direction) so that the angle of incidence of the light generated by the light source 1331 on the mask member 1320 is a predetermined angle θ1. Furthermore, the light guide 1332 is disposed at an angle relative to the vertical direction so that the angle of incidence of the image light emitted from the mask display unit 1310 on the retroreflector 5 is a predetermined angle θ1 (see FIG. 15 ). The exit angle of the image light emitted from the retroreflector 5 is a predetermined angle θ1, similar to the incident angle of the image light.

[0139] The optical element 1333 is configured by, for example, a collimator lens, and serves to reduce the diffusion angle of the light emitted by the light source 1331. In other words, the optical element 1333 converts the light emitted by the light source 1331 into approximately parallel light.

[0140] In this embodiment, the light source 1331 and the optical element 1333 are disposed above the light guide 1332. More specifically, the light source 1331 and the optical element 1333 are disposed above the light guide 1332 in the vertical direction (z direction) and facing the light guide 1332. Light emitted from the light source 1331 toward the vertically downward direction is reflected by the light guide 1332 via the optical element 1333 and is incident on the mask member 1320 obliquely downward.

[0141] In other words, the light source 1331 is disposed facing the light guide 1332 in a range overlapping with the light guide 1332 when viewed in a direction along the surface of the mask member 1320. As an example, the light source 1331 is disposed above the light guide 1332 so as to face the light guide 1332 when viewed in the vertical direction (z direction).

[0142] The image light emitted from the light source device 1330 configured as described above and transmitted through the mask member 1320 is incident on the retroreflector 5 obliquely downward, is reflected by the retroreflector 5 and travels obliquely upward. Then, a floating image 3, which is a still image of the push button, is formed on the outside of the transparent member 100.

[0143] Furthermore, in this embodiment, as described above, an image light control sheet 335 is disposed between the mask member 1320 and the retroreflector 5. The image light control sheet 335 is disposed outside the mask display unit 1310. The image light control sheet 335 may constitute a part of the mask display unit 1310. The image light control sheet 335 adjusts the traveling direction of light that has passed through the mask member 1320, i.e., the image light that is emitted from the mask display unit 1310, and is disposed along the vertical direction (z direction) like the mask member 1320 and the retroreflector 5.

[0144] As shown in Figure 19, the image light control sheet 335 has a sandwich structure in which transparent sections 336 made of transparent silicone and light-shielding sections 337 made of black silicone of a predetermined thickness are arranged alternately at predetermined intervals, and a synthetic resin layer (not shown) is arranged on the light incident and exit surfaces where light enters and exits.

[0145] The image light control sheet 335 is arranged in such a direction that the transparent portions 336 and the light-shielding portions 337 are alternately arranged in the z direction. Each light-shielding portion 337 extends continuously in the left-right direction (x direction) as viewed from the user 230. In other words, the multiple light-shielding portions 337 constituting the image light control sheet 335 are arranged in a so-called louvered shape. Note that, for example, a view angle control film (VCF) can be used as the image light control sheet 335.

[0146] Here, the light-shielding portions 337 of the image light control sheet 335 are preferably provided at an angle with respect to the vertical direction (z direction). More specifically, the light-shielding portions 337 are preferably provided at an angle with respect to the traveling direction (optical axis) of the chief ray L1 of the light that has passed through the mask member 1320, i.e., the light (image light) that forms the spatial floating image 3. In this embodiment, as described above, the chief ray L1 of the image light that has passed through the mask member 1320 is incident on the mask member 1320 at a predetermined angle θ1 with respect to the vertical direction (z direction). For this reason, the light-shielding portions 337 are also preferably provided at an angle with respect to the vertical direction (z direction) at a predetermined angle θ1.

[0147] As a result, the image light transmitted through the mask member 1320 passes through the transparent portion 336 of the image light control sheet 335 without being blocked more than necessary by the light-shielding portion 337. In other words, it is preferable that the image light control sheet 335 is arranged so as to impede the progression of the image light transmitted through the mask member 1320 as little as possible.

[0148] Furthermore, it is preferable that the shading portions 337 of the image light control sheet 335 are arranged so as to block the line of sight 230E of the viewer, the user 230. It is preferable that the shading portions 337 are arranged at a predetermined interval so that the user 230 cannot directly see the light inside the image light control sheet 335, i.e., the light inside the mask display unit 1310. This prevents the light inside the mask display unit 1310 from appearing to overlap the space-floating image 3, improving the visibility of the space-floating image 3 for the user 230. It is to be noted that the image light control sheet 335 is not an essential component and may be provided as needed.

[0149] The aerial operation detection sensor 1351 is a sensor that detects the operation of the floating image 3 by the finger of the user 230, and has the same configuration as in Example 1. In the floating image display device 1000A, when the user 230 touches the floating image 3, which is a still image of a push button, the touch operation by the user 230 is detected by the aerial operation detection sensor 1351.

[0150] In this embodiment, the aerial operation detection sensor 1351 is disposed above the transparent member 100 so as to be able to sense the finger of the user 230 from above. More specifically, the aerial operation detection sensor 1351 is disposed above the retroreflector 5 so as to be able to sense the display range of the floating-in-space image through the transparent member 100 (see FIG. 15 , etc.). As described above, a nail has a higher reflectivity than the pad of a finger. Therefore, by disposing the aerial operation detection sensor 1351 in this manner, the reflection of sensing light by the nail of the user 230 can be used for touch detection, thereby improving the accuracy of touch detection.

[0151] The aerial operation detection sensor 1351 may include, for example, a camera having an image sensor. The aerial operation detection unit 1350 may detect a touch operation on the floating-in-the-air image 3 by the user 230 based on an image captured by the camera. Furthermore, each aerial image display device 1300 does not necessarily have to include the aerial operation detection sensor 1351. For example, the aerial operation detection unit 1350 may detect a touch operation on the floating-in-the-air image 3 by the user 230 based on an image captured by the imaging unit 1180.

[0152] Furthermore, when the aerial operation detection sensor 1351 detects a touch operation on the floating in space image 3 by the user 230, the color of the image light forming the floating in space image 3 may be changed. For example, the color of the light emitted from the light source 1331, which is a multicolor LED light source or the like, may be changed. As an example, when a touch operation by the user 230 is not detected, the display color of the floating in space image 3 may be green, and while a touch operation by the user 230 is detected, the display color of the floating in space image 3 may be changed from green to red.

[0153] <<Block Diagram of Internal Configuration of Space-Floating Image Display Device>> Fig. 20 is a block diagram showing an example of the internal configuration of the space-floating image display device 1000A. Next, the internal configuration of the space-floating image display device 1000A according to Example 2, in particular the internal configuration of the spatial image display device 1300, will be described using the block diagram of Fig. 20. Note that in Fig. 20, the same components as those of the space-floating image display device 1000 according to Example 1 shown in Fig. 3 are assigned the same reference numerals, and duplicated explanations will be omitted. Also, in Fig. 20, the optical element 1333 is not shown.

[0154] As shown in Fig. 20 , the space-floating image display device 1000A of the second embodiment has a spatial image display device 1300. Although one spatial image display device 1300 is shown in Fig. 20 , as described above, the space-floating image display device 1000A of the second embodiment has three spatial image display devices 1300.

[0155] The aerial image display device 1300 includes a retroreflector 1101 corresponding to the retroreflector 5, and a mask display unit 1310. The mask display unit 1310 includes a light source 1331 and a light guide 1332 that constitute a light source device 1330, and a mask member 1320. The aerial image display device 1300 further includes 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, an aerial operation detection sensor 1351, an aerial operation detection unit 1350, etc. The change in the display color of the above-mentioned floating in space image 3 is executed by the control unit 1110, for example, based on the detection result of the aerial operation detection sensor 1351.

[0156] Furthermore, the spatial floating image display device 1000A may include, in addition to the spatial image display device 1300, a video signal input unit 1131, an audio signal input unit 1133, a communication unit 1132, an audio output unit 1140, a microphone 1139, a storage unit 1170, an imaging unit 1180, a removable media interface 1134, an attitude sensor 1113, a secondary battery 1112, etc., and the control unit 1110 can change the display color of the spatial floating image 3 based on signals input from the video signal input unit 1131 or the communication unit 1132.

[0157] Each component of the space-floating image display device 1000A is mainly arranged in the housing 1190. When the space-floating image display device 1000A includes a plurality of aerial image display devices 1300, it includes a plurality of each component of the aerial image display device 1300. However, some components, such as the control unit 1110, the non-volatile memory 1108, the operation input unit 1107, etc., may be common to the plurality of aerial image display devices 1300.

[0158] As explained above, the configuration of the space-floating image display device 1000A according to the second embodiment allows the floating image 3, which is a still image of a push button or the like, to be displayed with a relatively simple structure. As a result, the space-floating image display device 1000A can be made smaller and the cost can be reduced.

[0159] In the second embodiment, an example has been described in which the chief ray L1 of the space-floating image 3 formed by each aerial image display device 1300 travels parallel to the y-z plane, but the direction of the chief ray L1 of the space-floating image 3 is not particularly limited. The direction of the chief ray L1 of the space-floating image 3 formed by the aerial image display device 1300 may be inclined with respect to the y direction.

[0160] 21 , when the space-floating image display device 1000A is placed close to a wall W1, each aerial image display device 1300 may be placed in the housing 1190 so that the emission direction of the image light, that is, the direction of the chief ray L1 of the image light (direction of the optical axis) is inclined at a predetermined angle φ with respect to the wall surface of the wall W1. In other words, each aerial image display device 1300 may be placed in the housing 1190 so that the direction of the chief ray L1 of the space-floating image 3 is inclined at a predetermined angle φ with respect to the y direction.

[0161] In this example, the transparent member 100 is provided continuously along the x direction across the area facing the three aerial image display devices 1300. In other words, the transparent member 100 is provided in common to the three aerial image display devices 1300. Of course, the transparent member 100 may be provided independently for each aerial image display device 1300.

[0162] 21 , the aerial image display devices 1300 are arranged in a row along the x direction, tilted at a predetermined angle φ with respect to the y direction. That is, the plurality of spatial floating images 3 are arranged in a row along the x direction, tilted at a predetermined angle φ with respect to the y direction. The aerial image display devices 1300 are configured to be rotatable horizontally within the housing 1190. The predetermined angle φ at which the spatial floating images 3 are tilted can be adjusted as appropriate by rotating the aerial image display devices 1300.

[0163] This makes it easier for the user 230 to view the floating-in-space image 3 even when the floating-in-space image display device 1000A is installed near the wall W1 and the user 230 has to look at the floating-in-space image 3 at an angle to the front surface 1190a of the housing 1190. In other words, even when the line of sight 230E of the user 230 has to be in a direction that intersects with the y direction, the user 230 can easily view the floating-in-space image 3.

[0164] The space-floating images 3 do not necessarily have to be arranged in a row along the x direction. For example, as shown in FIG. 22 , the multiple space-floating images 3 may be arranged in a row inclined at a predetermined angle φ with respect to the y direction and in a direction perpendicular to the direction of the chief ray L1 of the light forming the space-floating images 3. In this case, it is preferable that the front surface 1190a of the housing 1190 is also formed in a direction perpendicular to the chief ray L1. It is also preferable that the transparent member 100 is formed in a direction perpendicular to the chief ray L1. This allows the multiple space-floating images 3 to be well formed on the outside of the transparent member 100.

[0165] Furthermore, in the above-described second embodiment, a configuration in which a plurality of aerial image display devices 1300 are arranged side by side in the horizontal direction has been exemplified as the space-floating image display device 1000A, but the arrangement direction of the aerial image display devices 1300 is not particularly limited. For example, as shown in FIG. 23 , a plurality of aerial image display devices 1300 may be arranged side by side in a line along the vertical direction (z direction). A plurality of space-floating images 3 may be displayed along the vertical direction (z direction). Of course, a plurality of space-floating images 3 may also be arranged side by side in an oblique direction. For example, a plurality of aerial image display devices 1300 may be arranged side by side in an oblique direction intersecting the vertical direction (z direction).

[0166] <Variation 1 of Example 2> Fig. 24 is a top view schematically showing the internal configuration of a spatial image display device according to Variation 1 of Example 2. Fig. 25 is a plan view showing an example of a spatial floating image according to Variation 1 of Example 2. Fig. 26 is a top view schematically showing another example of the internal configuration of a spatial image display device according to Variation 1 of Example 2. In the drawings, the same members as those in Example 2 described above are given the same reference numerals, and duplicated explanations will be omitted.

[0167] As shown in Fig. 24, each spatial image display device 1300 constituting the space floating image display device 1000A is provided with mirrors 1360A and 1360B as reflective members on both sides of the retroreflector 5. The mirrors 1360A and 1360B are collectively referred to as mirrors 1360. These mirrors 1360 are respectively provided on the outside of both ends of the retroreflector 5 in the left-right direction (x direction) as seen from the user 230. This makes it easier for the user 230 to view the space floating image 3.

[0168] As described above, the light emitted by the light source 1331 has a reduced diffusion angle and is converted into substantially parallel light by the optical element 1333. However, the light converted into substantially parallel light by the optical element 1333 still retains diffusion characteristics, and the image light that passes through the image light control sheet 335 also has diffusion characteristics.

[0169] For this reason, if the mirror 1360 is not provided, the image light (light rays) emitted from near the end of the mask member 1320 in the x direction will not be incident on the retroreflector 5, but will travel outside the retroreflector 5 in the D1 or D2 direction, as shown by the dotted arrow in Fig. 24. Therefore, for example, if the user 230 attempts to view the vicinity of both ends of the space-floating image 3 in an oblique direction from near the center of the retroreflector 5 in the x direction, it may be difficult to view the space-floating image 3. In other words, if the user 230 attempts to view the vicinity of both ends of the space-floating image 3 from near the center of the retroreflector 5 in the x direction, and as shown in Fig. 24, the line of sight 230E of the user 230 intersects with the y direction, it may be difficult to view the space-floating image 3.

[0170] In contrast, when the mirror 1360 is provided, the image light emitted from near the end of the mask member 1320 in the x direction is reflected by the mirror 1360 and enters the retroreflector 5, as shown by the solid arrow in Fig. 24. Furthermore, the image light emitted from the retroreflector 5 is reflected again by the mirror 1360 to form the floating image 3.

[0171] Therefore, even when the user 230 tries to view both ends of the space floating image 3 in an oblique direction from near the center of the retroreflector 5 in the x direction, that is, even when the user's line of sight 230E intersects with the y direction, the space floating image 3 can be easily viewed. In other words, the viewing angle of the space floating image 3 can be expanded. For example, as shown in FIG. 25 , this is particularly effective when the transmission portions 1321 of the mask member 1320 are formed up to near both ends in the x direction, and light is emitted from near both ends of the mask member 1320 in the x direction.

[0172] It is preferable that these mirrors 1360 are arranged along the chief ray L1 of the image light emitted from the mask member 1320. In this example, the chief ray L1 of the image light is along the y direction. For this reason, it is preferable that the mirrors 1360 are also arranged along the y direction. This more reliably improves the visibility of the space-floating image 3 for the user 230. Incidentally, if there is a large deviation between the direction of the surface of the mirror 1360 and the direction of the chief ray L1 of the image light, there is a risk that the space-floating image 3 will become a double image near the end in the x direction, thereby deteriorating visibility.

[0173] Furthermore, it is preferable that these mirrors 1360 are provided so as to protrude to the outside of the transparent member 100 in the y direction. In particular, it is preferable that the mirrors 1360 are provided continuously in the y direction from the mask member 1320 to a position corresponding to the floating image 3. This allows the image light emitted from the vicinity of both ends of the mask member 1320 in the x direction to be more reliably reflected by the mirrors 1360. As a result, it becomes easier for the user 230 to view the floating image 3 in space.

[0174] In this example, the configuration in which the mirrors 1360 are provided on the outer sides of both ends of the retroreflector 5 in the x direction has been described, but the mirrors 1360 do not necessarily have to be provided on both sides of the retroreflector 5. The mirror 1360 may be provided only on one end side of the retroreflector 5 in the x direction. For example, as shown in FIG. 26 , when one end of the space floating image display device 1000A in the x direction is installed close to the wall W2, the mirror 1360 may be provided only on the wall W2 side of the retroreflector 5.

[0175] As in this example, when there is a wall W2 on the left side of the space-floating image display device 1000A, it is difficult to imagine a situation in which the user 230 sees the vicinity of the right edge of the space-floating image 3 from the left outside of the space-floating image display device 1000A. Therefore, by providing the mirror 1360 only on the outside of the left end of the retroreflector 5, the visibility of the space-floating image 3 for the user 230 can be improved as described above.

[0176] <Modification 2 of Example 2> Fig. 27 is a side view schematically showing the internal configuration of a spatial image display device according to Modification 2 of Example 2. Fig. 28 is a side view schematically showing another example of the internal configuration of a spatial image display device according to Modification 2 of Example 2. Fig. 29 is a front view for explaining another example of a space floating image display device according to Modification 2 of Example 2. In the drawings, the same members as those in the above-mentioned Example 2 are given the same reference numerals, and duplicated explanations will be omitted.

[0177] 27 is an example further including a contact detector that detects contact of the user's 230 fingers with the transparent member 100, which is a protective plate. Specifically, in the space-floating image display device 1000A, the transparent member 100 is configured to be movable by a predetermined amount in the y direction. For example, when the user 230 presses the transparent member 100 with their finger, the transparent member 100 moves by a predetermined amount in the y direction.

[0178] A movement detector that detects movement of the transparent member 100 is provided inside the transparent member 100, i.e., on the retroreflector 5 side. As an example, a push switch 1370 serving as a movement detector is provided inside the transparent member 100 at a position that comes into contact when the transparent member 100 is pushed and moved. When the transparent member 100 moves and pushes the push switch 1370, the movement of the transparent member 100 is detected.

[0179] More specifically, in the space floating image display device 1000A of this example, the push switch 1370 detects contact of the transparent member 100 with the push switch 1370, and when the transparent member 100 is contacted with the push switch 1370, it is determined that the finger of the user 230 has contacted the transparent member 100. In other words, in this example, the push switch 1370 as a movement detector corresponds to a contact detector.

[0180] In such a configuration, when the user 230 touches the floating image 3, even if the touch operation is not detected by the aerial operation detection sensor 1351, the transparent member 100 is pressed, so that the touch operation by the user 230 can be reliably detected.

[0181] The floating-in-space image display device 1000A shown in FIG. 28 is an example that includes a capacitance sensor 1380 provided on the transparent member 100 as a contact detector that detects contact of the fingers of the user 230 with the transparent member 100, which is a protective plate.

[0182] As an example, the capacitance sensor 1380 is provided over the entire surface of the transparent member 100 facing the user 230. The capacitance sensor 1380 is only required to detect contact of the user 230's fingers with the transparent member 100 when the user 230 touches the floating-in-space image 3, and its arrangement and formation area are not particularly limited. The capacitance sensor 1380 may be provided, for example, only in the area of ​​the transparent member 100 that corresponds to the floating-in-space image 3.

[0183] 28 further includes a vibration generator 1390 that generates vibrations when a capacitance sensor 1380, which is a contact detector, detects that the user 230 has made a finger contact with the transparent member 100. In this example, the vibration generator 1390 is provided inside the transparent member 100, that is, on the retroreflector 5 side. The vibration generator 1390 is provided in contact with the lower part of the transparent member 100.

[0184] When the capacitance sensor 1380 detects contact of the fingers of the user 230 with the transparent member 100, the vibration generator 1390 vibrates. In this example, the aerial operation detection sensor 1351 detects a touch operation on the floating-in-space image 3 by the user 230, and when the capacitance sensor 1380 detects contact of the fingers of the user 230 with the transparent member 100, the vibration generator 1390 vibrates. The vibration generated by the vibration generator 1390 is transmitted to the fingers of the user 230 via the transparent member 100.

[0185] This allows the user 230 to reliably recognize that a touch operation on the floating image 3 has been detected. Therefore, even if the user 230 is, for example, visually impaired, the user can reliably recognize that the floating image 3 has been touched.

[0186] Furthermore, for example, as shown in Fig. 29, Braille 1400 regarding the content of the space-floating image 3 may be provided below the area where the space-floating image 3 is displayed on the transparent member 100 functioning as a protective plate. This allows the visually impaired user 230 to correctly recognize the content of the space-floating image 3. Note that in this example, the Braille 1400 is provided below each space-floating image 3, but it goes without saying that the position where the Braille 1400 is provided is not particularly limited.

[0187] The technology according to this embodiment displays high-resolution, high-brightness video information in a floating state, allowing users to operate the device without worrying about contact infection. Applying the technology according to this embodiment to a system used by an unspecified number of users reduces the risk of contact infection and provides a contactless user interface that can be used without anxiety. This contributes to the United Nations' Sustainable Development Goals (SDGs), which aim to "ensure good health and well-being for all."

[0188] Furthermore, the technology according to this embodiment reduces the divergence angle of the emitted image light and aligns it with a specific polarization, thereby efficiently reflecting only the normal reflected light from the retroreflector, resulting in high light utilization efficiency and enabling the production of bright and clear floating images. The technology according to this embodiment can provide a highly usable non-contact user interface that can significantly reduce power consumption. This contributes to the achievement of the United Nations' Sustainable Development Goals (SDGs): "Build resilient infrastructure, promote inclusive and sustainable industrialization, and promote technological innovation and infrastructure" and "Make cities and towns sustainable."

[0189] Various embodiments have been described above in detail. However, the present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments are detailed descriptions of the entire system in order to clearly explain the present invention, and the present invention is not necessarily limited to a system including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0190] 1...display device, 2, 5...retroreflector (retroreflector), 3...spatial image (space-floating image), 105...window glass, 100...transparent member, 13...light source device, 54...light direction conversion panel, 102, 202...LED substrate, 203...light guide, 205, 271...reflector sheet, 206, 270...phase difference plate, 230...user, 335...image light control sheet, 1000, 1000A...space-floating image display device, 1110...control control section, 1160...image control section, 1180...imaging section, 1102...image display section, 1300...aerial image display device (aerial image display unit), 1310...mask display unit, 1320...mask member, 1321...transmissive section, 1322...low-transmissive section, 1323...non-transmissive section, 1330...light source device, 1331...light source, 1332...light guide, 1333...optical element, 1350...air operation detection section, 1351...air operation detection sensor

Claims

1. A floating-in-the-air image display device comprising: a light source device; a mask member arranged so that light emitted from the light source device is incident at an oblique angle and having a transparent portion of a predetermined shape that transmits the incident light; a retroreflective member that reflects the light that has transmitted through the mask member and displays a floating-in-the-air image, which is a real image, in the air using the reflected light; and an operation detector that detects operation of the floating-in-the-air image by a user.

2. A floating-in-the-air image display device as claimed in claim 1, comprising an image light control sheet disposed between said mask member and said retroreflective member, which transmits light that has passed through said mask member.

3. A floating-in-the-air image display device as claimed in claim 1, wherein the light source device comprises: a light source; and a light guide that guides the light emitted from the light source so that it is incident on the mask member at an oblique angle.

4. A floating-in-the-air image display device as claimed in claim 3, wherein the light source device further comprises an optical element disposed between the light source and the light guide for reducing the diffusion angle of the light emitted from the light source.

5. A floating-in-the-air image display device as described in claim 3, wherein the light source emits light directed diagonally downward, and the floating image is displayed by light directed diagonally upward by the retroreflective member, and the light source is positioned above the light guide, facing the light guide.

6. An air-floating image display device as described in claim 1, comprising a reflective member arranged on the outside of at least one end of the retroreflective member in the direction of the chief ray of light emitted from the light source device.

7. A floating-in-the-air image display device according to claim 6, wherein the reflective members are disposed on the outsides of both ends of the retroreflective member.

8. A floating-in-the-air image display device according to claim 6, wherein the reflective member is provided continuously from the mask member to the portion corresponding to the floating image.

9. A floating image display device as claimed in claim 1, further comprising a protective plate made of a transparent material and disposed between the retroreflective member and the floating image, wherein the floating image is displayed by light transmitted through the protective plate.

10. A floating-in-the-air image display device according to claim 9, further comprising a contact detector for detecting contact of the user's fingers with the protective plate.

11. A floating-in-the-air image display device as described in claim 10, wherein the contact detector detects contact of the protective plate with the contact detector, and when the protective plate comes into contact with the contact detector, determines that the user's fingers have come into contact with the protective plate.

12. A floating image display device according to claim 10, wherein the contact detector is a capacitance sensor provided on the protective plate.

13. A floating image display device according to claim 11, further comprising a vibration generator attached to the protective plate, which generates vibrations when the contact detector detects contact of the user's fingers with the protective plate.

14. A floating-in-the-air image display device according to claim 1, comprising a plurality of mask display units each including the light source device and the mask member.

15. A floating-in-the-air image display device as described in claim 1, wherein the light source device is configured to be able to emit light of a plurality of colors, and when the operation detector detects an operation of the floating-in-the-air image by the user, the color of the emitted light is changed.

16. A floating-in-the-air image display device according to claim 1, wherein the floating image is a still image of a push button.

Images