Aerial floating video display device

Abstract

To provide a more suitable aerial floating video display device, contributing to sustainable development goals: 3, Good Health and Well-Being; 9, Industry, Innovation and Infrastructure; 11, Sustainable Cities and Communities.SOLUTION: Provided is an aerial floating video display device, comprising: a light source device; a mask member having a transmission part of a prescribed shape for allowing incident light to pass through and disposed so that light emitted from the light source device enters in a diagonal direction; a retroreflective member for reflecting light having passed through the mask member and displaying an aerial floating video which is a real image in the air by reflected light; and an operation detector for detecting an operation performed on the aerial floating video by a user.SELECTED DRAWING: Figure 15

Description

Technical Field

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

Background Art

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

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

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

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

Means for Solving the Problems

[0006] In order to solve the above problems, for example, the configuration described in the claims is adopted. This application includes a plurality of means for solving the above problems. For example, an airborne video display device comprising a light source device, a mask member having a transmission portion of a predetermined shape arranged so that light emitted from the light source device is incident obliquely and transmitting the incident light, a retroreflective member arranged parallel to the mask member, reflecting the light transmitted through the transmission portion, and displaying a real image of an airborne video in the air by the reflected light, and an operation detector for detecting an operation of the airborne video by a user may be configured.

Effects of the Invention

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

Brief Description of the Drawings

[0008]

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Modes for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the description of the embodiments, and various changes and modifications can be made by those skilled in the art within the scope of the technical idea disclosed in this specification. Also, in all the drawings for explaining the present invention, those having the same function may be given the same reference numerals, and the repeated description thereof may be omitted.

[0010] The following embodiments relate to a video display device capable of transmitting a video by video light from a video light source through a transparent member that partitions a space such as glass and displaying it as a space-floating video outside the transparent member. In the description of the following embodiments, a video floating in space is expressed by the term "space-floating video". Instead of this term, it may be expressed as "aerial image", "space image", "aerial floating video", "space-floating optical image of a display video", "aerial floating optical image of a display video", etc. The term "space-floating video" mainly used in the description of the embodiments is used as a representative example of these terms.

[0011] According to the following embodiments, for example, a video display device suitable for use in bank ATMs, station ticket vending machines, digital signage, etc. can be realized. For example, currently, touch panels are usually used in bank ATMs, station ticket vending machines, etc., but by using a transparent glass surface or a light-transmissive plate material, high-resolution video information can be displayed in a state of floating in space on this glass surface or light-transmissive plate material. At this time, by reducing the divergence angle of the emitted video light, that is, making it an acute angle, and further aligning it with a specific polarization, only the regular reflected light can be efficiently reflected to the retroreflective plate, so the light utilization efficiency is high, and in addition to the main space-floating image that has been a problem in the conventional retroreflective method, the ghost image that occurs can be suppressed, and a clear space-floating video can be obtained. In addition, an apparatus including the light source of this embodiment can provide a novel and highly usable space-floating video display device (space-floating video display system) capable of significantly reducing power consumption. Also, for example, a vehicle-use space-floating video display device capable of so-called unidirectional space-floating video display that is visible inside and / or outside the vehicle can be provided. <Example 1>

[0012] <An example of the usage form of the space-floating video display device> FIG. 1 is a diagram showing an example of a usage form of a spatial floating image display device according to an embodiment of the present invention, and is a diagram showing the overall configuration of the spatial floating image display device according to this embodiment. The specific configuration of the spatial floating image display device will be described in detail with reference to FIG. 2 and the like. Light with a specific polarization and a sandwiching angle directivity characteristic is emitted as an image light beam from the image display device 1, once enters the retroreflective plate 2 after being reflected by the optical system in the spatial floating image display device, is retroreflected, passes through a transparent member 100 (such as glass), and forms a real image, an aerial image (spatial floating image 3), outside the glass surface. In the following embodiments, the retroreflective plate 2 (retroreflective plate) will be used as an example of the retroreflective member for explanation. However, the retroreflective plate 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 retroreflective member attached to a planar or non-planar member, or an entire assembly in which a sheet-like retroreflective member is attached to a planar or non-planar member. Further, since the light rays after reflection by the retroreflective plate 2 have imaging optical characteristics, the retroreflective plate 2 may be expressed as an imaging optical member or an imaging optical plate.

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

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

[0015] <Configuration Example of the Optical System of the Spatial Floating Image Display Device> A configuration example of the optical system of the spatial floating image display device will be described with reference to FIG. 2A. The optical system of FIG. 2A is an optical system using a retroreflective plate 5. Hereinafter, with reference to FIGS. 2A to 2F, the configuration example of the optical system will be described more specifically.

[0016] Figure 2A is a diagram showing an example of the main configuration and the retroreflective portion configuration of a spatial floating image display device according to an embodiment of the present invention. In an oblique direction of a transparent member 100 such as glass, a display device 1 that emits image light is provided. The display device 1 includes a liquid crystal display panel 11 and a light source device 13 that generates light.

[0017] The principal ray 9020 representing the light beam emitted from the display device 1 travels toward the retroreflective plate 5 and is incident on the retroreflective plate 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 for example, it can also be used at 45° ± 15°.

[0018] The retroreflective plate 5 is an optical member having an optical property of retroreflecting light at least in some directions. Further, since the reflected light has an optical property of forming an image, the retroreflective plate 5 may be expressed as an imaging optical member or an imaging optical plate.

[0019] The specific configuration of the retroreflective plate 5 will be described in detail with reference to FIG. 2B, FIG. 2C, etc. By the retroreflective plate 5, the principal ray 9020 is retroreflectively reflected in the x and y directions while traveling in the z direction. As a result, the reflected ray 9021 travels in a direction away from the retroreflective plate 5 along an optical path that is mirror-symmetric with respect to the principal ray 9020 with respect to the retroreflective plate 5, passes through the transparent member 100, and forms a spatial floating image 3 as a real image on the imaging surface.

[0020] The light beam that forms the spatial floating image 3 is a set of light rays converging from the retroreflector 5 to the optical image of the spatial floating image 3, and these light rays continue to travel straight even after passing through the optical image of the spatial floating image 3. Therefore, unlike the diffused image formed on a screen by a general projector or the like, the spatial floating image 3 is an image with high directivity. Thus, in the configuration of FIG. 2A, when viewed by the user from the direction of arrow A, the spatial floating image 3 is viewed as a bright image. However, when viewed by another person from the direction of arrow B, the spatial floating image 3 cannot be viewed as an image at all. This characteristic is suitable for use in a system that displays an image that requires high security or an image with high confidentiality that needs to be hidden from a person facing the user.

[0021] An example of the configuration of the retroreflector 5 will be described with reference to FIGS. 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 with reference to FIGS. 2D, 2E, and 2F. The light rays 9111, 9112, 9113, and 9114 emitted from the light source 9110 are reflected twice by the two mirror surfaces 9041 and 9042 of the corner reflector 9040 to become the reflected light rays 9121, 9122, 9123, and 9124. This double reflection is a retroreflective reflection that folds back in the same direction as the incident direction (travels in the direction rotated by 180°) with respect to the x and y directions, and is a normal reflection in which the incident angle and the reflection angle coincide due to total reflection with respect to the z direction.

[0022] That is, the light rays 9111 to 9114 generate reflected light rays 9121 to 9124 on a straight line symmetric with respect to the z direction with respect to the corner reflector 9040, and form an aerial 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. Depending on the diffusion characteristics of the light source 9110, the light rays incident on the retroreflective plate 5 are not limited to these, but any incident light ray causes a similar reflection and forms an aerial image 9120. Note that, for ease of viewing the drawing, the position of the light source 9110 and the x-direction position of the aerial image 9120 are shifted in the drawing, but actually the position of the light source 9110 and the x-direction position of the aerial image 9120 are the same position, and they overlap when viewed from the z direction.

[0023] Next, the configuration and effects of the corner reflector 9040 constituting the retroreflective plate 5 will be described with reference to FIGS. 2D, 2E, and 2F. The corner reflector 9040 is a rectangular parallelepiped in which only two specific surfaces are mirror surfaces 9041 and 9042, and the other four surfaces are formed of transparent members. The retroreflective plate 5 has a configuration in which the corner reflectors 9040 are arranged in an array such that their corresponding mirror surfaces face the same direction.

[0024] When viewed from the upper surface (+z direction), the light ray 9111 emitted from the light source 9110 enters the mirror surface 9041 (or mirror surface 9042) at a specific incident angle, 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 mirror surface 9041).

[0025] Assuming that the incident angle of the light ray 9111 with respect to the mirror surface 9041 (or mirror surface 9042) is θ, the incident angle of the first reflected light ray 9131 reflected by the mirror surface 9041 (or mirror surface 9042) with respect to the mirror surface 9042 (or mirror surface 9041) can be expressed as 90° - θ. Therefore, with respect to the light ray 9111, the second reflected light ray 9121 obtains a rotation of 2θ by the first reflection and 2×(90° - θ) by the second reflection, resulting in a total reverse optical path of 180°. On the other hand, when viewed from the side (the intermediate direction between -x and -y), total internal reflection with respect to the z direction occurs only once. Therefore, assuming that the incident angle with respect to the mirror surface 9041 or mirror surface 9042 is φ, the reflected light ray 9121 obtains a rotation of 2×φ by one reflection with respect to the light ray 9111.

[0026] From the above, the light rays incident on the corner reflector 9040 produce a recursive reflection with a reverse optical path in the x and y directions and a regular reflection by total internal reflection in the z direction. Considering the retroreflective plate 5, similar reflections are caused in each optical path. Therefore, due to the reverse optical path with convergence in the x and y directions, an image is formed at a point symmetric with respect to the z-axis direction.

[0027] In the optical system of Fig. 2A, the retroreflective plate 5 has a recursive reflection characteristic in two axial directions and a regular reflection in the other one axial direction. As a result, when a diffusive incident light beam is incident on the retroreflective plate 5, the convergent reflected light beam reflected by the corner reflector array travels toward the side opposite to the side where the light source of the incident light ray exists with respect to the retroreflective plate 5. The convergent reflected light beam forms an image in the air and forms a spatial floating image 3.

[0028] The traveling direction of the principal ray of the converging reflected light beam reflected by the corner reflector array of the retroreflector 5 does not oppose the traveling direction of the principal ray of the diffused incident light beam incident on the retroreflector 5. The component in the normal direction of the plate-shaped surface of the retroreflector 5 with respect to the traveling direction of the principal ray of the diffused incident light beam incident on the retroreflector 5 and the component in the normal direction of the plate-shaped surface of the retroreflector 5 with respect to the traveling direction of the principal ray after the reflected light beam has become a converging reflected light beam by reflection on the retroreflector 5 travel straight without changing before and after reflection by the corner reflector array.

[0029] That is, by reflection in the retroreflector 5, the diffused incident light beam is converted into a converging reflected light beam, but in the normal direction of the plate-shaped surface of the retroreflector 5, the light beam travels through the retroreflector 5. Here, the diffused incident light beam incident on the retroreflector 5 and the converging reflected light beam emitted from the retroreflector 5 are geometrically symmetric with respect to the plate-shaped surface of the retroreflector 5.

[0030] The resolution of the spatially floating image formed by the light beam from the video output unit 10 greatly depends on the diameter D and pitch P (not shown) of the retroreflective portion of the retroreflector 5 shown in FIGS. 2B and 2C in addition to the resolution of the liquid crystal display panel 11. For example, when using a 7-inch WUXGA (1920×1200 pixels) liquid crystal display panel, even if 1 pixel (1 triplet) is about 80 μm, if the diameter D of the retroreflective portion is 240 μm and the pitch P is 300 μm, for example, 1 pixel of the spatially floating image corresponds to 300 μm. Therefore, the effective resolution of the spatially floating video is reduced to about 1 / 3.

[0031] Therefore, in order to make the resolution of the spatially floating video equivalent to the resolution of the display device 1, it is desirable to bring the diameter D and pitch P of the retroreflective portion closer to 1 pixel of the liquid crystal display panel. On the other hand, in order to suppress the occurrence of moiré due to the pixels of the retroreflector and the liquid crystal display panel, it is advisable to design with the respective pitch ratios outside an integer multiple of 1 pixel. Also, the shape should be arranged so that none of the sides of the retroreflective portion overlap any of the sides of 1 pixel of the liquid crystal display panel.

[0032] Note that the shape of the retroreflective plate (image-forming optical plate) according to this embodiment is not limited to the above example. It may have various shapes that realize retroreflection. Specifically, various cubic corner bodies, corner reflector arrays may be used, or a slit mirror array, a two-sided corner reflector array, a multi-sided reflector array, or a shape in which combinations of its reflecting surfaces are periodically arranged may be used. Alternatively, a capsule lens type retroreflective element in which glass beads are periodically arranged may be provided on the surface of the retroreflective plate of this embodiment. Since the detailed configuration of these retroreflective elements may use existing technologies, detailed description thereof is omitted. Specifically, the technologies disclosed in JP-A-2017-33005, JP-A-2019-133110, JP-A-2017-67933, WO2009 / 131128, etc. may be used.

[0033] Note that in the optical system of FIG. 2A, the video light emitted from the display device 1 may be in any polarization state. There is no problem whether it is S-polarized light or P-polarized light.

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

[0035] According to the optical system of FIG. 2A described above, a brighter and higher-quality floating image can be provided.

[0036] <<Block Diagram of the Internal Configuration of the Floating Image Display Device>>

[0037] Next, a block diagram of the internal configuration of the floating image display device 1000 will be described. FIG. 3 is a block diagram showing an example of the internal configuration of the floating image display device 1000.

[0038] The spatial floating image display device 1000 includes a retroreflective unit 1101, an image display unit 1102, a light guide 1104, a light source 1105, a power supply 1106, an external power input interface 1111, an operation input unit 1107, a non-volatile 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 air operation detection sensor 1351, an air operation detection unit 1350, an audio output unit 1140, a microphone 1139, a video control unit 1160, a storage unit 1170, an imaging unit 1180, etc. In addition, it may be provided with 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, etc.

[0039] Each component of the spatial floating image display device 1000 is arranged in a housing 1190. Note that the imaging unit 1180 and the air operation detection sensor 1351 shown in FIG. 3 may be provided outside the housing 1190.

[0040] The retroreflective unit 1101 in FIG. 3 corresponds to the retroreflective plate 5 in FIG. 2A. The retroreflective unit 1101 retroreflects the light modulated by the image display unit 1102. Among the reflected light from the retroreflective unit 1101, the spatial floating image 3 is formed by the light output to the outside of the spatial floating image display device 1000.

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

[0043] The light source 1105 generates light for the video display unit 1102 and is a solid light source such as an LED light source or a laser light source. The power supply 1106 converts the AC current input from the outside through the external power supply input interface 1111 into a DC current and supplies power to the light source 1105. Also, the power supply 1106 supplies the necessary DC current to each part within the spatial floating video display device 1000. The secondary battery 1112 stores the power supplied from the power supply 1106. Also, when no power is supplied from the outside through the external power supply input interface 1111, the secondary battery 1112 supplies power to the light source 1105 and other components that require power. That is, when the spatial floating video display device 1000 is equipped with the secondary battery 1112, the user can use the spatial floating video display device 1000 even when no power is supplied from the outside.

[0044] The light guide 1104 guides the light generated by the light source 1105 and irradiates the video display unit 1102. The combination of the light guide 1104 and the light source 1105 can also be referred to as the backlight of the video display unit 1102. The light guide 1104 may mainly be configured using glass. The light guide 1104 may mainly be configured using plastic. The light guide 1104 may be configured using a mirror. Various methods can be considered for the combination of the light guide 1104 and the light source 1105. Specific configuration examples of the combination of the light guide 1104 and the light source 1105 will be described in detail later.

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

[0046] Specific examples of the air operation detection sensor 1351 include distance sensors using invisible light such as infrared rays, invisible light lasers, ultrasonic waves, etc. Also, the air operation detection sensor 1351 may be configured by combining a plurality of sensors in a plurality of ways so as to be able to detect coordinates in a two-dimensional plane. Further, the air operation detection sensor 1351 may be composed of a ToF (Time of Flight) type LiDAR (Light Detection and Ranging) or an image sensor.

[0047] The air operation detection sensor 1351 only needs to be able to sense a touch operation or the like by the user 230 on the object displayed as the floating image 3 in space. Such sensing can be performed using existing technologies.

[0048] The air operation detection unit 1350 acquires a sensing signal from the air operation detection sensor 1351, and based on the sensing signal, determines the presence or absence of contact of the object of the floating image 3 in space by the finger of the user 230, calculates the position (contact position) where the finger of the user 230 and the object are in contact, and so on. The air operation detection unit 1350 is composed of a circuit such as an FPGA (Field Programmable Gate Array), for example. Also, some functions of the air operation detection unit 1350 may be realized by software by a space operation detection program executed by the control unit 1110, for example.

[0049] The air operation detection sensor 1351 and the air operation detection unit 1350 may be incorporated into the spatial floating video display device 1000, or may be provided externally as a separate unit from the spatial floating video display device 1000. When provided as a separate unit from the spatial floating video display device 1000, the air operation detection sensor 1351 and the air operation detection unit 1350 are configured to be able to transmit information and signals to the spatial floating video display device 1000 via a wired or wireless communication connection path or a video signal transmission path.

[0050] Also, the air operation detection sensor 1351 and the air operation detection unit 1350 may be provided as separate units. Thereby, it is possible to construct a system in which the spatial floating video display device 1000 without the air operation detection function is used as the main body, and only the air operation detection function can be added as an option. Further, only the air operation detection sensor 1351 may be a separate unit, and the air operation detection unit 1350 may be incorporated into the spatial floating video display device 1000. When it is desired to arrange the air operation detection sensor 1351 more freely with respect to the installation position of the spatial floating video display device 1000, etc., there is an advantage in a configuration in which only the air operation detection sensor 1351 is a separate unit.

[0051] The imaging unit 1180 is a camera having an image sensor, and images the space near the spatial floating video 3 and / or the face, arm, finger, 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 air operation detection unit 1350 can be assisted during the detection process of the touch operation of the spatial floating video 3 by the user 230. The imaging unit 1180 may be provided as a separate unit from the spatial floating video display device 1000. When the imaging unit 1180 is provided as a separate unit from the spatial floating video display device 1000, it may be configured to be able to transmit an imaging signal to the spatial floating video display device 1000 via a wired or wireless communication connection path or the like.

[0052] For example, when the air operation detection sensor 1351 is configured as an object intrusion sensor that detects the presence or absence of an object entering a plane (intrusion detection plane) including the display surface of the spatial floating image 3, the air operation detection sensor 1351 may not be able to detect information such as how far an object (e.g., a user's finger) that has not entered the intrusion detection plane is from the intrusion detection plane, or how close the object is to the intrusion detection plane.

[0053] In such a case, by using information such as the depth calculation information of the object based on the captured images of the plurality of imaging units 1180 and the depth information of the object by the depth sensor, the distance between the object and the intrusion detection plane can be calculated. And these information and various information such as the distance between the object and the intrusion detection plane are used for various display controls for the spatial floating image 3.

[0054] Further, the air operation detection unit 1350 may detect a touch operation of the spatial floating image 3 by the user 230 based on the captured image of the imaging unit 1180 without using the air operation detection sensor 1351.

[0055] Further, the imaging unit 1180 may capture the face of the user 230 who operates the spatial floating image 3, and the control unit 1110 may perform identification processing of the user 230. Also, in order to determine whether there is someone standing around or behind the user 230 who operates the spatial floating image 3 and whether the person is peeping at the operation of the user 230 on the spatial floating image 3, the imaging unit 1180 may capture a range including the user 230 who operates the spatial floating image 3 and the surrounding area of the user 230.

[0056] The operation input unit 1107 is, for example, an operation button, a signal reception unit such as a remote controller, or an infrared light receiving unit, and inputs a signal for an operation different from the air operation (touch operation) by the user 230. Separately from the aforementioned user 230 who performs a touch operation on the spatial floating image 3, the operation input unit 1107 may be used, for example, by an administrator to operate the spatial floating image display device 1000.

[0057] The video signal input unit 1131 connects to an external video output device and inputs video data. Various digital video input interfaces can be considered for the video signal input unit 1131. For example, it may be configured with a video input interface compliant with the HDMI (Registered Trademark) (High-Definition Multimedia Interface) standard, a video input interface compliant with the DVI (Digital Visual Interface) standard, or a video input interface compliant with 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 with an audio input interface compliant with the HDMI standard, an optical digital terminal interface, or a coaxial digital terminal interface, etc. In the case of an interface compliant with the HDMI standard, the video signal input unit 1131 and the audio signal input unit 1133 may be configured as an integrated interface with integrated terminals and cables. 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 composed of speakers.

[0059] Also, the audio output unit 1140 may output built-in operation sounds or error warning sounds. Alternatively, the audio output unit 1140 may be configured to output digital signals to external devices, such as the Audio Return Channel function defined in the HDMI standard. The microphone 1139 is a microphone that picks up sounds around the spatial floating video display device 1000, converts them into signals, and generates audio signals. The microphone may record the voice of a person, such as the user's voice, and the generated audio signal may be configured such that the control unit 1110, described later, performs speech recognition processing to obtain character information from the audio signal.

[0060] The non-volatile memory 1108 stores various data used in the spatial floating image display device 1000. The data stored in the non-volatile memory 1108 includes, for example, data for various operations to be displayed in the spatial floating image 3, display icons, data of objects to be operated by the user's operations, layout information, and the like. The memory 1109 stores video data to be displayed as the spatial floating image 3, control data of the device, and the like.

[0061] The control unit 1110 controls the operations of each connected unit. Further, the control unit 1110 may perform arithmetic processing based on the information acquired from each unit within the spatial floating image display device 1000 in cooperation with the program stored in the memory 1109.

[0062] The communication unit 1132 communicates with external devices, external servers, etc. via a wired or wireless communication interface. When the communication unit 1132 has a wired communication interface, the wired communication interface may be configured by, for example, a LAN interface conforming to the Ethernet standard. When the communication unit 1132 has a wireless communication interface, it may be configured by, for example, a communication interface of the Wi-Fi system, a communication interface of the Bluetooth system, a mobile communication interface such as 4G or 5G. Through the communication via the communication unit 1132, various data such as video data, image data, and audio data are transmitted and received.

[0063] Also, 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 element 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 various data including 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 spatial floating image 3 via the video display unit 1102 and the retroreflective unit 1101.

[0064] The storage unit 1170 is a storage device for recording various information such as various data including video data, image data, and audio data. The storage unit 1170 may be composed of 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 information such as various data including video data, image data, and audio data may be recorded in the storage unit 1170 in advance when the product is shipped. Also, the storage unit 1170 may record various information such as various data including video data, image data, and audio data acquired from an external device or an external server via the communication unit 1132.

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

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

[0067] The video control unit 1160 performs various controls on the video signal input to the video display unit 1102. The video control unit 1160 may also be referred to as a video processing circuit and may be composed of hardware such as an ASIC, an FPGA, or a video processor, for example. Note that 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 performs controls such as video switching, for example, which video signal among the video signals stored in the memory 1109 and the video signals (video data) input to the video signal input unit 1131 is to be input to the video display unit 1102.

[0068] Also, the video control unit 1160 may generate a superimposed video signal by superimposing the video signal stored in the memory 1109 and the video signal input from the video signal input unit 1131, and perform control to form a composite video as the floating video 3 in space by inputting the superimposed video signal to the video display unit 1102.

[0069] Also, the video control unit 1160 may perform control to perform image processing on the video signal input from the video signal input unit 1131, the video signal stored in the memory 1109, etc. Examples of the image processing include scaling processing such as enlarging, reducing, and deforming an image, brightness adjustment processing for changing the brightness, contrast adjustment processing for changing the contrast curve of the image, and retinex processing for decomposing an image into light components and changing the weighting for each component.

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

[0071] The posture sensor 1113 is a sensor composed of a gravity sensor, an acceleration sensor, or a combination thereof, and can detect the posture in which the spatial floating video display device 1000 is installed. Based on the posture detection result of the posture sensor 1113, the control unit 1110 may control the operations of the connected components. For example, when an unfavorable posture as the user's usage state is detected, the control may be performed to stop the display of the video being displayed on the video display unit 1102 and display an error message to the user. Alternatively, when the posture sensor 1113 detects that the installation posture of the spatial floating video display device 1000 has changed, the control may be performed to rotate the display direction of the video being displayed on the video display unit 1102.

[0072] As described so far, the spatial floating video display device 1000 is equipped with various functions. However, the spatial floating video display device 1000 does not necessarily need to have all of these functions, and any configuration may be used as long as it has the function of forming the spatial floating video 3.

[0073] <Configuration Example of Spatial Floating Video Display Device> Next, a configuration example of the spatial floating video display device will be described. The layout of the components of the spatial floating video display device according to this embodiment can have various layouts depending on the usage form. Hereinafter, each layout of FIGS. 4A to 4C will be described. In any of the examples of FIGS. 4A to 4C, the thick line surrounding the spatial floating video display device 1000 shows an example of the housing structure of the spatial floating video display device 1000.

[0074] FIG. 4A is a diagram showing an example of the configuration of a spatial floating image display device. The spatial floating image display device 1000 in FIG. 4A is a spatial floating image display device that employs the optical system of FIG. 2A. An image light that has passed through the transparent member 100 forms an image in the air as the spatial floating image 3. Also, using the sensing light of the air operation detection sensor 1351 disposed on the back side of the transparent member 100 as viewed by the user, it is possible to detect an operation on the spatial floating image 3 by the finger 9004 of the user. Note that the x direction is the left-right direction as viewed by the user, the y direction is the front-rear direction (depth direction) as viewed by the user, and the z direction is the up-down direction (vertical direction). Since the definitions of the x direction, y direction, and z direction are the same in each figure after FIG. 4A, repeated explanations are omitted.

[0075] Even in the example of the spatial floating image display device that employs the optical system of FIG. 2A, the spatial floating image 3 forms an image in front of the transparent member 100, and using the sensing light of the air operation detection sensor 1351 disposed on the back side of the transparent member 100 as viewed by the user, it is possible to detect an operation on the spatial floating image 3 by the finger of the user.

[0076] Next, FIG. 4B is a diagram showing an example of the configuration of a spatial floating image display device. FIG. 4B is a diagram showing the internal optical system configuration of the spatial floating image display device 1000 in FIG. 4A. The spatial floating image display device 1000 shown in FIG. 4B is equipped with an optical system corresponding to the optical system of FIG. 2A. In the spatial floating image display device 1000 shown in FIG. 4B, it is installed horizontally so that the surface on which the spatial floating image 3 is formed faces upward.

[0077] That is, in FIG. 4B, in the spatial floating image display device 1000, the transparent member 100 is installed on the upper surface of the device. The spatial floating image 3 is formed above the surface of the transparent member 100 of the spatial floating image display device 1000. The light of the spatial floating image 3 travels in an obliquely upward direction. When the air operation detection sensor 1351 is provided as shown in the figure, it is possible to detect an operation on the spatial floating image 3 by the finger of the user 230.

[0078] Also, in FIG. 4B, the display device 1 and the floating image 3 are in a plane-symmetric relationship with respect to the plane of the retroreflective plate 5.

[0079] FIG. 4C is a diagram showing an example of the configuration of the floating image display device. The floating image display device 1000 shown in FIG. 4C is equipped with an optical system corresponding to the optical system of FIG. 2A. The floating image display device 1000 shown in FIG. 4C is installed vertically so that the surface on which the floating image 3 is formed faces the front (the direction of the user 230) of the floating image display device 1000. That is, in FIG. 4C, the transparent member 100 of the floating image display device 1000 is installed on the front (the direction of the user 230) of the device. The floating image 3 is formed on the surface of the transparent member 100 of the floating image display device 1000 on the user 230 side. The light of the floating image 3 travels in an obliquely upward direction. When the air operation detection sensor 1351 is provided as shown in FIG. 4C, the operation of the floating image 3 by the finger of the user 230 can be detected. Here, as shown in FIG. 4C, the air operation detection sensor 1351 can use the reflection of the sensing light by the nail of the user 230 for touch detection by sensing the finger of the user 230 from above. Generally, since the nail has a higher reflectivity than the fingertip, the accuracy of touch detection can be improved by configuring the air operation detection sensor 1351 in this way.

[0080] According to the configuration of the floating image display device in FIGS. 4A to 4C, a user-friendly floating image display device using the optical system of FIG. 2A can be realized.

[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 a light source device 13 that constitutes its light source together with the video display element 11 (liquid crystal display panel). In FIG. 5, the light source device 13 is shown as a developed perspective view together with the liquid crystal display panel.

[0082] As shown by arrow 30 in FIG. 5, this liquid crystal display panel (image display element 11) receives an illumination light beam having diffusion characteristics with a sandwiching angle, that is, characteristics similar to a laser beam having strong directivity (linear propagation) and with the polarization planes aligned in one direction, from a light source device 13 which is a backlight device. The liquid crystal display panel (image display element 11) modulates the received illumination light beam according to the input video signal. The modulated video light is reflected by the retroreflective plate 2, passes through the transparent member 100, and forms a spatial floating image which is a real image (see FIG. 1).

[0083] Also, in FIG. 5, the liquid crystal display panel 11 constituting the display device 1, further includes a light direction conversion panel 54 for controlling the directivity characteristics of the emitted light beam from the light source device 13, and an optional sandwiching angle diffuser plate (not shown). That is, polarizing plates are provided on both sides of the liquid crystal display panel 11, and the video light of a specific polarization modulates the light intensity according to the video signal and is emitted (see arrow 30 in FIG. 5). Thus, a desired video is projected as light of a specific polarization with high directivity (linear propagation) through the light direction conversion panel 54 toward the retroreflective plate 2. After being reflected by the retroreflective plate 2, it passes through toward the eyes of a monitor outside the store (space) to form a spatial floating video 3. Note that a protective cover 50 (see FIGS. 6 and 7) may be provided on the surface of the above-described light direction conversion panel 54.

[0084] <Example 1 of Display Device> FIG. 6 shows an example of the specific configuration of the display device 1. In FIG. 6, a liquid crystal display panel 11 and a light direction conversion panel 54 are arranged on the light source device 13 of FIG. 5. This light source device 13 is formed of, for example, plastic on the case shown in FIG. 5, and houses an LED element 201 and a light guide 203 inside. On the end face of the light guide 203, as shown in FIG. 5 and the like, in order to convert the divergent light from each LED element 201 into a substantially parallel light beam, it has a shape in which the cross-sectional area gradually increases toward the light receiving part, and has an action such that the divergence angle gradually decreases by total internal reflection multiple times when propagating inside. A lens shape is provided. On the upper surface of the display device 1, a liquid crystal display panel 11 constituting such a display device 1 is attached. Further, on one side surface (the left end face in this example) of the case of the light source device 13, an LED (Light Emitting Diode) element 201 which is a semiconductor light source and an LED substrate 202 on which its control circuit is mounted are attached. A heat sink, which is a member for cooling the heat generated by the LED element and the control circuit, may be attached to the outer surface of the LED substrate 202.

[0085] In addition, on the frame (not shown) of the liquid crystal display panel attached to the upper surface of the case of the light source device 13, there are attached a liquid crystal display panel 11 attached to the frame, and further, an FPC (Flexible Printed Circuits) (not shown) electrically connected to the liquid crystal display panel 11, etc., and it is configured. That is, the liquid crystal display panel 11, which is an image display element, together with the LED element 201, which is a solid light source, modulates the intensity of transmitted light based on a control signal from a control circuit (image control unit 1160 in FIG. 3) that constitutes an electronic device, thereby generating a display image. At this time, since the generated image light has a narrow diffusion angle and only a specific polarization component, a novel image display device that is close to a surface-emitting laser image source driven by an image signal can be obtained. At present, it is technically and safety-wise impossible to obtain a laser light beam of the same size as the image obtained by the above-described display device 1 using a laser device. Therefore, in this embodiment, for example, light close to the above-described surface-emitting laser image light is obtained from the light beam from a general light source equipped with an LED element.

[0086] Subsequently, 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 together with FIG. 6.

[0087] Since FIGS. 6 and 7 are cross-sectional views, only one of the plurality of LED elements 201 that constitute the light source is shown, and these are converted into substantially collimated light by the shape of the light-receiving end face 203a of the light guide 203. For this reason, the light-receiving part of the light guide end face and the LED element are attached while maintaining a predetermined positional relationship.

[0088] Note that each of these light guides 203 is formed of a light-transmissive resin such as acrylic. The LED light-receiving surface at the end of the light guide 203 has, for example, an outer peripheral surface in a conical convex shape obtained by rotating a parabolic cross-section. At the top, it has a concave portion with a convex portion (i.e., a convex lens surface) formed at its central portion, and at the central portion of its flat portion, it has a convex lens surface protruding outward (alternatively, it may be a concave lens surface recessed inward) (not shown). Note that the outer shape of the light-receiving portion of the light guide to which the LED element 201 is attached forms a parabolic surface shape that forms a conical outer peripheral surface, and is set within an angle range that enables total internal reflection of the light emitted from the LED element in the peripheral direction inside it, or a reflecting surface is formed.

[0089] On the other hand, the LED elements 201 are respectively arranged at predetermined positions on the surface of the LED substrate 202, which is their circuit board. The LED substrate 202 is arranged and fixed with respect to the LED collimator (light-receiving end face 203a) such that the LED elements 201 on its surface are respectively positioned at the central portions of the aforementioned concave portions.

[0090] According to such a configuration, due to the shape of the light-receiving end face 203a of the light guide 203, the light emitted from the LED element 201 can be taken out as substantially parallel light, and the utilization efficiency of the generated light can be improved.

[0091] As described above, the light source device 13 is configured by attaching a light source unit in which a plurality of LED elements 201, which are light sources, are arranged to the light-receiving end face 203a, which is the light-receiving portion provided at the end face of the light guide 203. The divergent light beam from the LED element 201 is made into substantially parallel light by the lens shape of the light-receiving end face 203a of the light guide end face, and as shown by the arrow, is guided inside the light guide 203 (in a direction parallel to the drawing), and is emitted toward the liquid crystal display panel 11 arranged substantially parallel to the light guide 203 (in a direction perpendicular to the front from the drawing) by the light beam direction conversion means 204. By optimizing the distribution (density) of the light beam direction conversion means 204 according to the shape inside or on the surface of the light guide, the uniformity of the light beam incident on the liquid crystal display panel 11 can be controlled.

[0092] The above-described light beam direction conversion means 204 emits the light beam propagating within the light guide body toward the liquid crystal display panel 11 arranged substantially parallel to the light guide body 203 (in the direction perpendicular to the front from the drawing surface), depending on the shape of the surface of the light guide body or by providing, for example, portions with different refractive indices inside the light guide body. At this time, if the relative luminance ratio when comparing the luminance of the center of the screen and the peripheral portion of the screen in a state where the liquid crystal display panel 11 is facing the center of the screen and the viewpoint is placed at the same position as the diagonal dimension of the screen is 20% or more, there is no practical problem, and if it exceeds 30%, it has even better characteristics.

[0093] Note that FIG. 6 is a cross-sectional layout view for explaining the configuration and operation of the light source of the present embodiment that performs polarization conversion in the light source device 13 including the above-described light guide body 203 and the LED element 201. In FIG. 6, the light source device 13 includes, for example, a light guide body 203 provided with light beam direction conversion means 204 on its surface or inside formed of plastic or the like, an LED element 201 as a light source, a reflection sheet 205, a retardation plate 206, a lenticular lens, etc. A liquid crystal display panel 11 provided with polarizing plates on its upper surface at the light source light incident surface and the video light output surface is attached.

[0094] Also, a film or sheet-shaped reflective polarizing plate 49 is provided on the light source light incident surface (the lower surface in the figure) of the liquid crystal display panel 11 corresponding to the light source device 13, and selectively reflects one-sided polarization wave (for example, P wave) 212 of the natural light beam 210 emitted from the LED element 201. The reflected light is reflected again by the reflection sheet 205 provided on one (lower side in the figure) surface of the light guide body 203 so as to be directed toward the liquid crystal display panel 11. Therefore, a retardation plate (λ / 4 plate) is provided between the reflection sheet 205 and the light guide body 203 or between the light guide body 203 and the reflective polarizing plate 49, and the light is reflected by the reflection sheet 205 and passed twice to convert the reflected light beam from P polarization to S polarization, thereby improving the utilization efficiency of the light source light as video light. The video light beam whose light intensity is modulated by the video signal in the liquid crystal display panel 11 (arrow 213 in FIG. 6) enters the retroreflective plate 2. After being reflected by the retroreflective plate 2, a spatial floating image that is a real image can be obtained.

[0095] FIG. 7 is a cross-sectional layout view for explaining the configuration and operation of the light source of this embodiment that performs polarization conversion in the light source device 13 including the light guide 203 and the LED element 201, similar to FIG. 6. Similarly, the light source device 13 is also composed of, for example, a light guide 203 provided with a light beam direction conversion means 204 on the surface or inside formed of plastic or the like, an LED element 201 as a light source, a reflection sheet 205, a retardation plate 206, a lenticular lens, and the like. On the upper surface of the light source device 13, a liquid crystal display panel 11 having polarizing plates on the light source light incident surface and the video light emitting surface is attached as a video display element.

[0096] Also, on the light source light incident surface (the lower surface in the figure) of the liquid crystal display panel 11 corresponding to the light source device 13, a film or sheet-like reflective polarizing plate 49 is provided to selectively reflect one-sided polarized waves (for example, S waves) 211 of the natural light beam 210 emitted from the LED element 201. That is, in the example of FIG. 7, the selective reflection characteristics of the reflective polarizing plate 49 are different from those in FIG. 7. The reflected light is reflected by the reflection sheet 205 provided on one side (the lower side in the figure) of the light guide 203 and then travels again toward the liquid crystal display panel 11. A retardation plate (λ / 4 plate) is provided between the reflection sheet 205 and the light guide 203 or between the light guide 203 and the reflective polarizing plate 49 and reflected by the reflection sheet 205 and passed twice to convert the reflected light beam from S polarization to P polarization, thereby improving the utilization efficiency of the light source light as video light. The video light beam whose light intensity is modulated by the video signal in the liquid crystal display panel 11 (arrow 214 in FIG. 7) enters the retroreflective plate 2. After being reflected by the retroreflective plate 2, a spatial floating image that is a real image can be obtained.

[0097] In the light source devices shown in FIGS. 6 and 7, in addition to the action of the polarizing plate provided on the light incident surface of the corresponding liquid crystal display panel 11, since one-sided polarization components are reflected by the reflective polarizing plate, the theoretically obtained contrast ratio is the reciprocal of the cross transmittance of the reflective polarizing plate multiplied by the reciprocal of the cross transmittance obtained by the two polarizing plates attached to the liquid crystal display panel. As a result, high contrast performance can be obtained. Actually, it was experimentally confirmed that the contrast performance of the displayed image was improved by more than 10 times. As a result, a high-quality video comparable to that of self-emitting organic EL was obtained.

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

[0099] Further, on the liquid crystal display panel frame attached to the upper surface of the case, the liquid crystal display panel 11 attached to the frame and, further, an FPC (Flexible Printed Circuits) 403 electrically connected to the liquid crystal display panel 11 are attached and configured. That is, the liquid crystal display panel 11 which is a liquid crystal display element, together with the LED elements 14a and 14b which are solid light sources, modulates the intensity of transmitted light based on a control signal from a control circuit (not shown here) constituting the electronic device, thereby generating a display image.

[0100] <Example 3 of the display device> Subsequently, with reference to FIG. 9, another example (Example 3 of the display device) of the specific configuration of the display device 1 will be described. The light source device of this display device 1 converts the diverging light beam (in which P-polarized light and S-polarized light are mixed) from the LED into a substantially parallel light beam by the collimator 18 and reflects it toward the liquid crystal display panel 11 by the reflecting surface of the reflection type light guide 304. The reflected light enters the reflection type polarizing plate 49 disposed between the liquid crystal display panel 11 and the reflection type light guide 304. The reflection type polarizing plate 49 transmits light of a specific polarization (for example, P-polarized light) and makes the transmitted polarized light enter the liquid crystal display panel 11. Here, light of other polarizations (for example, S-polarized light) other than the specific polarization is reflected by the reflection type polarizing plate 49 and heads back to the reflection type light guide 304 again.

[0101] The reflective polarizing plate 49 is installed at an inclination with respect to the liquid crystal display panel 11 so as not to be perpendicular to the principal ray of light from the reflecting surface of the reflective light guide 304. Then, the principal ray of the light reflected by the reflective polarizing plate 49 enters the transmissive surface of the reflective light guide 304. The light that has entered the transmissive 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 transmissive surface of the reflective light guide 304. The light that has passed through the transmissive surface of the reflective light guide 304 enters the reflective polarizing plate 49 again.

[0102] At this time, since the light that enters the reflective polarizing plate 49 again has passed through the λ / 4 plate 270 twice, the polarization is converted into a polarization (for example, P-polarization) that passes 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. Regarding the polarization design related to polarization conversion, the polarization can be configured in the reverse direction (reversing S-polarization and P-polarization) from the above description.

[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, is luminance-modulated according to the video signal, and a video is displayed on the panel surface. A plurality of LEDs constituting the light source are shown as in the above example (however, only one is shown in FIG. 9 due to the longitudinal section), and these are attached to the collimator 18 at predetermined positions.

[0104] Note that each of the collimators 18 is formed of, for example, a translucent resin such as acrylic or glass. The collimator 18 may have an outer peripheral surface in a conical convex shape obtained by rotating a parabolic cross section. Further, a recess having a convex portion (i.e., a convex lens surface) may be formed at the central portion of the top of the collimator 18 (the side facing the LED substrate 102). Further, a convex lens surface protruding outward (or a concave lens surface recessed inward may also be acceptable) is provided at the central portion of the flat surface portion of the collimator 18 (the side opposite to the above-mentioned top). Note that the parabolic surface forming the conical outer peripheral surface of the collimator 18 is set within a range of angles that enables total internal reflection of the light emitted from the LED in the peripheral direction inside the collimator 18, or a reflecting surface is formed.

[0105] Note that the LEDs are respectively arranged at predetermined positions on the surface of the LED substrate 102, which is the circuit board of the LEDs. The LED substrate 102 is arranged and fixed with respect to the collimator 18 such that the LEDs on its surface are respectively positioned at the central portion of the top of the conical convex shape (or the recess if there is a recess at the top).

[0106] According to such a configuration, among the light emitted from the LED, in particular, the light emitted from the central portion thereof is condensed by the convex lens surface forming the outer shape of the collimator 18 and becomes parallel light. Further, the light emitted from other portions in the peripheral direction is reflected by the parabolic surface forming the conical outer peripheral surface of the collimator 18 and is similarly condensed to become parallel light. In other words, according to the collimator 18 having a convex lens formed at its central portion and a parabolic surface formed at its peripheral portion, almost all of the light generated by the LED can be taken out as parallel light, and the utilization efficiency of the generated light can be improved.

[0107] Furthermore, the light converted into substantially parallel light by the collimator 18 shown in FIG. 9 is reflected by the reflective light guide 304. Among this light, the light of a specific polarization passes through the reflective polarizing plate 49 due to the action of the reflective polarizing plate 49, and the light of the other polarization reflected by the action of the reflective polarizing plate 49 passes through the light guide 304 again. The light is reflected by a reflector 271 that is located at a position opposite to the liquid crystal display panel 11 with respect to the reflective light guide 304. At this time, the light is converted in polarization by passing through the λ / 4 plate 270, which is a retardation plate, twice. The light reflected by the reflector 271 passes through the light guide 304 again and enters the reflective polarizing plate 49 provided on the opposite surface. Since the incident light has been subjected to polarization conversion, it passes through the reflective polarizing plate 49 and is incident on the liquid crystal display panel 11 with its polarization directions aligned. As a result, all the light from the light source can be utilized, so the geometric optical utilization efficiency of the light is doubled. Also, since the polarization degree (extinction ratio) of the reflective polarizing plate is also multiplied by the extinction ratio of the entire system, the contrast ratio of the entire display device is significantly improved by using the light source device of this embodiment. By adjusting the surface roughness of the reflecting surface of the reflective light guide 304 and the surface roughness of the reflector 271, the light reflection diffusion angle at each reflecting surface can be adjusted. The surface roughness of the reflecting surface of the reflective light guide 304 and the surface roughness of the reflector 271 may be adjusted for each design so that the uniformity of the light incident on the liquid crystal display panel 11 becomes more suitable.

[0108] Note that the λ / 4 plate 270, which is the retardation plate in FIG. 9, does not necessarily need to have a retardation of λ / 4 with respect to the polarization incident perpendicularly to the λ / 4 plate 270. In the configuration of FIG. 9, any retardation plate that changes the phase by 90° (λ / 2) when the polarization passes through it twice is acceptable. The thickness of the retardation plate may be adjusted according to the incident angle distribution of the polarization.

[0109] <Example 4 of the display device> Furthermore, another example (Example 4 of the display device) of the configuration of the optical system such as the light source device of the display device will be described with reference to FIG. 10. This is a configuration example in the case where a diffusion sheet is used instead of the reflective light guide 304 in the light source device of Example 3 of the display device. Specifically, two optical sheets (optical sheet 207A and optical sheet 207B) for converting the diffusion characteristics in the vertical and horizontal directions (not shown in the front-back direction of the drawing) of the drawing are used on the light-emitting side of the light from the collimator 18, and the light from the collimator 18 is made to enter between the two optical sheets (diffusion sheets).

[0110] Note that the above optical sheet may be a single sheet instead of two sheets. In the case of a single-sheet configuration, the vertical and horizontal diffusion characteristics are adjusted by the fine shapes of the front and back surfaces of the single optical sheet. Also, a plurality of diffusion sheets may be used to share the functions. Here, in the example of FIG. 10, regarding the reflection and diffusion characteristics due to the front and back surface shapes of the optical sheet 207A and the optical sheet 207B, it is advisable to perform optimal design with the number of LEDs, the divergence angle from the LED substrate (optical element) 102, and the optical specifications of the collimator 18 as design parameters so that the surface density of the light beam emitted from the liquid crystal display panel 11 becomes uniform. That is, the diffusion characteristics are adjusted by the surface shapes of a plurality of diffusion sheets instead of the light guide.

[0111] In the example of FIG. 10, the polarization conversion is performed in the same manner as in Example 3 of the display device described above. That is, in the example of FIG. 10, the reflective polarizing plate 49 may be configured to have the characteristic of reflecting S-polarized light (transmitting P-polarized light). In that case, among the light emitted from the LED which is the light source, the P-polarized light is transmitted and the transmitted light enters the liquid crystal display panel 11. Among the light emitted from the LED which is the light source, the S-polarized light is reflected, and the reflected light passes through the retardation plate 270 shown in FIG. 10. The light that has passed through the retardation plate 270 is reflected by the reflector 271. The light reflected by the reflector 271 is converted into P-polarized light by passing through the retardation plate 270 again. The polarization-converted light passes through the reflective polarizing plate 49 and enters the liquid crystal display panel 11.

[0112] Note that the quarter-wave plate 270, which is the phase difference plate in Fig. 10, does not necessarily need to have a phase difference of λ / 4 with respect to the polarized light incident perpendicularly to the quarter-wave plate 270. In the configuration of Fig. 10, any phase difference plate that changes the phase by 90° (λ / 2) when the polarized light passes through it twice is acceptable. The thickness of the phase difference plate may be adjusted according to the incident angle distribution of the polarized light. Also, in Fig. 10, regarding the polarization design related to polarization conversion, the polarization may be configured in the reverse way (reversing the S polarization and P polarization) from the above description.

[0113] The light emitted from the liquid crystal display panel 11 has similar diffusion characteristics in both the horizontal direction of the screen (displayed on the X-axis in Fig. 12(a)) and the vertical direction of the screen (displayed on the Y-axis in Fig. 12(b)) in a general TV application device. In contrast, for the diffusion characteristics of the light beam emitted from the liquid crystal display panel of this embodiment, for example, as shown in Example 1 of Fig. 12, when the viewing angle at which the luminance becomes 50% of the front view (angle 0 degrees) is set to 13 degrees, it becomes 1 / 5 compared to 62 degrees of a general TV application device. Similarly, for the viewing angle in the vertical direction, the reflection angle of the reflective light guide and the area of the reflection surface, etc. are optimized so that the upper viewing angle is suppressed to about 1 / 3 of the lower viewing angle with unevenness in the up and down directions. As a result, compared to a conventional liquid crystal TV, the amount of video light directed toward the monitoring direction is significantly improved, and the luminance becomes 50 times or more.

[0114] Furthermore, for the viewing angle characteristics shown in Example 2 of Fig. 12, when the viewing angle at which the luminance becomes 50% of the front view (angle 0 degrees) is set to 5 degrees, it becomes 1 / 12 compared to 62 degrees of a general TV application device. Similarly, for the viewing angle in the vertical direction, the reflection angle of the reflective light guide and the area of the reflection surface, etc. are optimized so that the viewing angle is suppressed to about 1 / 12 of a general TV application device with equality in the up and down directions. As a result, compared to a conventional liquid crystal TV, the amount of video light directed toward the monitoring direction is significantly improved, and the luminance becomes 100 times or more.

[0115] As described above, by using the viewing angle as the included angle, the amount of light flux directed toward the monitoring direction can be concentrated, so the light utilization efficiency is greatly improved. As a result, even when using a liquid crystal display panel for general TV use, by controlling the light diffusion characteristics of the light source device, it is possible to achieve a significant increase in brightness with the same power consumption, and it can be made into a video display device corresponding to an information display system for bright outdoors.

[0116] When using a large liquid crystal display panel, the light around the screen is directed inward so that it heads toward the viewer when the viewer is facing the center of the screen, thereby improving the overall uniformity of the screen brightness. FIG. 11 shows the convergence angles of the long side and the short side of the panel when the distance L from the viewer to the panel and the panel size (screen ratio 16:10) are used as parameters. When monitoring with the screen in a vertical orientation, the convergence angle can be set according to the short side. For example, when using a 22-inch panel vertically and the monitoring distance is 0.8 m, if the convergence angle is set to 10 degrees, the video light from the four corners of the screen can be effectively directed toward the viewer.

[0117] Similarly, when monitoring with a 15-inch panel vertically and the monitoring distance is 0.8 m, if the convergence angle is set to 7 degrees, the video light from the four corners of the screen can be effectively directed toward the viewer. As described above, by directing the video light around the screen to the viewer who is in the optimal position to monitor the center of the screen according to the size of the liquid crystal display panel and whether it is used vertically or horizontally, the overall uniformity of the screen brightness can be improved.

[0118] As a basic configuration, as shown in FIG. 9, a light flux with an included angle directivity characteristic is made incident on the liquid crystal display panel 11 by a light source device, and the video information displayed on the screen of the liquid crystal display panel 11 is modulated in brightness according to the video signal, and the spatially floating image obtained by reflecting with a retroreflective plate is displayed outdoors or indoors through a transparent member 100.

[0119] By using the display device and the light source device according to an embodiment of the present invention described above, it is possible to realize a spatially floating image display device with higher light utilization efficiency.

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

[0121] As shown in FIGS. 13 to 15, the spatial floating image display device 1000A according to Example 2 displays a spatial floating image 3 which is a still image. As an example, the spatial floating image display device 1000A displays three still images of a push button, namely, an "A" button, a "B" button, and a "C" button, as the spatial floating image 3. In other words, the spatial floating image display device 1000A functions as an air button operation panel having a plurality of air buttons that are displayed as the spatial floating image 3 and operated by the user 230. Note that the number of the spatial floating images 3 displayed by the spatial floating image display device 1000A is not particularly limited, and may be four or more, and of course, may be two or less. That is, the spatial floating image display device 1000A may include three spatial image display devices 1300 as shown in FIG. 13, or may include three or more spatial image display devices 1300, or may include only one spatial image display device 1300.

[0122] The spatial floating image display device 1000A according to Example 2 is installed vertically so that the surface on which the spatial floating image 3 is formed faces the front of the spatial floating image display device 1000A (faces the user 230 side), in the same manner as the example shown in FIG. 4C. That is, the spatial floating image display device 1000A is installed vertically so that the transparent member 100 faces the user 230 side.

[0123] In the spatial floating image display device 1000A, similar to the example in FIG. 4C, the image light reflected by the retroreflective plate 5 travels obliquely upward, and a spatial floating image 3 is formed on the user 230 side with respect to the transparent member 100. However, in the spatial floating image display device 1000A, the spatial floating image 3 is formed along the vertical direction (z direction). In other words, the spatial floating image 3 is formed so as to face the horizontal direction (y direction). Incidentally, in the spatial floating image display device 1000 shown in FIG. 4C, the spatial floating image 3 is formed so as to face a direction (diagonally upward direction) intersecting the y direction. Of course, also in the spatial floating image display device 1000A of the second embodiment, the spatial floating image 3 may be directed obliquely upward.

[0124] Further, the spatial floating image display device 1000A is installed so that the spatial floating image 3 is formed at a position lower than the eye level of the user 230. In other words, the spatial floating image display device 1000A is installed, for example, on the floor surface or the like so that the line of sight 230E when the user 230 views the spatial floating image 3 in a standing state is obliquely downward. As described above, since the light forming the spatial floating image 3 travels in an obliquely upward direction, by forming the spatial floating image 3 at such a height, the user 230 can easily visually recognize the spatial floating image 3 and can also easily perform operations with fingers.

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

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

[0127] Note that the transparent member 100 is provided to close the opening of the housing 1190 and functions as a protective plate for protecting the devices arranged inside the housing 1190. In this example, the transparent member 100 is provided independently corresponding to each spatial image display device 1300. However, the transparent member 100 may be provided commonly for the three spatial image display devices 1300.

[0128] As shown in FIG. 15, each spatial image display device 1300 includes the above - described retro - reflective plate 5 and a mask display unit 1310. The mask display unit 1310 includes a mask member 1320 and a light source device 1330. Further, each spatial image display device 1300 includes an image light control sheet 335, an air operation detection sensor 1351 as an air operation detector, etc. The retro - reflective plate 5 and the mask member 1320 are arranged substantially parallel to the transparent member 100 along the vertical direction (z - direction). For this reason, the spatial floating image 3 is formed along the vertical direction (z - direction) in the vicinity outside the transparent member 100.

[0129] The retro - reflective plate 5 is arranged close to and parallel to the transparent member 100. In this embodiment, the retro - reflective plate 5 is arranged with a gap from the transparent member 100, but it may be in contact with the transparent member 100. Also, the retro - reflective plate 5 and the transparent member 100 do not necessarily have to be arranged parallel. Since the configuration of the retro - reflective plate 5 itself is the same as that in the first embodiment, the description here is omitted.

[0130] The mask display unit 1310 emits light of an arbitrary shape as image light by transmitting the light emitted by the light source device 1330 through the mask member 1320. As shown in an example in FIG. 16, the mask member 1320 includes a predetermined-shaped transmission portion 1321 through which the light incident from the light source device 1330 passes, and a low-transmission portion 1322 having a lower light transmittance than the transmission portion 1321. In the example shown in FIG. 16, the circular white portion is the transmission portion 1321. The portion of the alphabet "A" is the low-transmission portion 1322, which has a lower transmittance than the transmission portion 1321 but allows light to pass through. The black-painted portion around the transmission portion 1321 is the non-transmission portion 1323, and the light incident from the light source device 1330 hardly passes through it.

[0131] Note that the non-transmission portion 1323 is a portion having a lower light transmittance than the transmission portion 1321 and is included in the low-transmission portion 1322. Also, in this embodiment, the portion of the alphabet "A" is set as the low-transmission portion 1322 through which light passes, but this portion may be set as the non-transmission portion 1323 through which light does not pass.

[0132] This mask member 1320 is formed by reducing the transmittance of a part 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 the region that becomes the transmission portion 1321. The material of the base substrate is not particularly limited as long as it is a transparent material, and for example, glass, plastic, etc. are preferably used.

[0133] The method of reducing the transmittance of the base substrate, that is, the method of forming the mask member 1320 is not particularly limited, and for example, the following methods can be mentioned. As an example, a method of selectively applying a coating that absorbs or reflects visible light to the surface of the base substrate can be mentioned. In this method, the portion of the base substrate where the coating is not applied becomes the transmission portion 1321, and the portion where the coating is applied becomes the low-transmission portion 1322. Also, for example, printing with ink that absorbs light may be performed on the portion of the base substrate that becomes the low-transmission portion 1322. Further, for the non-transmission portion 1323, for example, it may be formed by adhering a thin plate that does not transmit light, such as metal, to the surface of the base substrate.

[0134] The light (video light) that has passed through the mask member 1320 is incident on the retroreflective plate 5, and as shown in FIG. 17, a still image of a circular "A" button is displayed as the floating image 3 in the air. Among the floating images 3 in space shown in FIG. 17, a first region A1, which is a white portion, is a portion formed by the light that has passed through the transmissive portion 1321 of the mask member 1320. Also, a second region A2 corresponding to the alphabet "A" is a portion formed by the light that has passed through the low-transmissive portion 1322 of the mask member 1320 and is darker than the first region A1. A third region A3, which is black-painted in the figure, is a portion where the light is blocked by the non-transmissive portion 1323 of the mask member 1320, and actually, the background can be seen.

[0135] In this way, in the spatial image display device 1300 included in the spatial floating image display device 1000A, the video light emitted from the mask display unit 1310 is reflected by the retroreflective plate 5, and a still image of a push button operated by the finger of the user 230 is displayed as the floating image 3 in space outside the transparent member 100. Also, as described above, the spatial floating image display device 1000A includes three spatial image display devices 1300, and still images of three buttons, an "A" button, a "B" button, and a "C" button, are displayed as the 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 disposed between the light source 1331 and the light guide 1332.

[0137] The light source 1331 generates light for forming the floating image 3, which is a still image, and for example, it may be any device that emits visible light such as a lamp, a monochromatic LED light source, a multi-color LED light source, or a laser light source.

[0138] The light guide 1332 is composed of, for example, a reflective mirror, guides the light generated by the light source 1331, and makes it incident obliquely downward on the mask member 1320. That is, the light guide 1332 guides the light generated by the light source 1331 so that it is incident obliquely downward on the mask member 1320. The light guide 1332 is arranged to be inclined with respect to the incident direction of light to the light guide 1332, which is the vertical direction (z-direction) in this example. Specifically, the light guide 1332 is arranged to be inclined with respect to the vertical direction (z-direction) such that the incident angle at which the light generated by the light source 1331 is incident on the mask member 1320 is a predetermined angle θ1. More specifically, the light guide 1332 is arranged to be inclined with respect to the vertical direction such that the incident angle of the image light emitted from the mask display unit 1310 with respect to the retroreflector 5 is a predetermined angle θ1 (see FIG. 15). Note that the emission angle of the image light emitted from the retroreflector 5 is the same predetermined angle θ1 as the incident angle of the image light.

[0139] The optical element 1333 is for reducing the divergence angle of the light emitted by the light source 1331 and is composed of, for example, a collimator lens. In other words, the optical element 1333 converts the light emitted by the light source 1331 into substantially parallel light.

[0140] Here, in this embodiment, the light source 1331 and the optical element 1333 are arranged above the light guide 1332. More specifically, the light source 1331 and the optical element 1333 are arranged above the light guide 1332 in the vertical direction (z-direction) of the light guide 1332 and are directed toward the light guide 1332. The light emitted from the light source 1331 downward in the vertical direction is reflected by the light guide 1332 via the optical element 1333 and is incident obliquely downward on the mask member 1320.

[0141] In other words, the light source 1331 is arranged to be directed toward the light guide 1332 within a range overlapping the light guide 1332 when viewed in the direction along the surface of the mask member 1320. As an example, the light source 1331 is arranged 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 with such a configuration and transmitted through the mask member 1320 is incident obliquely downward on the retroreflective plate 5, reflected by the retroreflective plate 5, and travels obliquely upward. Then, a spatial floating image 3, which is a still image of a push button, is formed outside the transparent member 100.

[0143] Also, in this embodiment, as described above, an image light control sheet 335 is disposed between the mask member 1320 and the retroreflective plate 5. The image light control sheet 335 is disposed outside the mask display unit 1310. Note that the image light control sheet 335 may constitute a part of the mask display unit 1310. This image light control sheet 335 adjusts the traveling direction of the light transmitted through the mask member 1320, that is, the image light emitted from the mask display unit 1310, and is disposed along the vertical direction (z direction) in the same manner as the mask member 1320 and the retroreflective plate 5.

[0144] As shown in FIG. 19, the image light control sheet 335 has a transparent portion 336 made of transparent silicon and a light-shielding portion 337 made of black silicon with a predetermined thickness alternately arranged at a predetermined interval, and a synthetic resin layer (not shown) is disposed on the light incident / output surface where light enters or exits to form a sandwich structure.

[0145] The image light control sheet 335 is disposed such 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. That is, the plurality of light-shielding portions 337 constituting the image light control sheet 335 are provided in a so-called louver shape. Note that, for example, a viewing angle control film (VCF) can be used as the image light control sheet 335.

[0146] Here, the light-shielding portion 337 of the video light control sheet 335 is preferably provided to be inclined with respect to the vertical direction (z direction). More specifically, it is preferably provided to be inclined along the traveling direction (optical axis) of the principal ray L1 of the light that has passed through the mask member 1320, that is, the light forming the spatial floating image 3 (video light). In the present embodiment, as described above, the principal ray L1 of the video 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). Therefore, it is preferable that the light-shielding portion 337 is also provided to be inclined at a predetermined angle θ1 with respect to the vertical direction (z direction).

[0147] Thereby, the video light that has passed through the mask member 1320 passes through the transparent portion 336 of the video light control sheet 335 without being blocked more than necessary by the light-shielding portion 337. That is, it is preferable that the video light control sheet 335 is arranged so as not to interfere with the traveling of the video light that has passed through the mask member 1320 as much as possible.

[0148] Also, the light-shielding portion 337 of the video light control sheet 335 is preferably arranged so as to block the line of sight 230E of the user 230 who is the viewer. The light-shielding portions 337 are preferably arranged at a predetermined interval so that the user 230 cannot directly visually recognize the light inside the video light control sheet 335, that is, the light inside the mask display unit 1310. Thereby, the light inside the mask display unit 1310 does not overlap and appear on the spatial floating image 3, and the visibility of the spatial floating image 3 by the user 230 is improved. Note that the video light control sheet 335 is not an essential component and may be provided as necessary.

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

[0150] In this embodiment, the air operation detection sensor 1351 is disposed on the upper part of the transparent member 100 so that the finger of the user 230 can be sensed from above. More specifically, the air operation detection sensor 1351 is disposed above the retroreflective plate 5 so that it can sense the display range of the spatially floating image through the transparent member 100 (see FIG. 15 etc.). As described above, the nail has a higher reflectivity than the fingertip. Therefore, by arranging the air operation detection sensor 1351 in such a manner, the reflection of the sensing light by the nail of the user 230 can be utilized for touch detection, thereby improving the accuracy of touch detection.

[0151] Note that the air operation detection sensor 1351 may include, for example, a camera having an image sensor. The air operation detection unit 1350 may detect a touch operation on the spatially floating image 3 by the user 230 based on the captured image by the camera. Further, each spatial image display device 1300 does not necessarily have to be provided with the air operation detection sensor 1351. For example, the air operation detection unit 1350 may detect a touch operation on the spatially floating image 3 by the user 230 based on the captured image of the imaging unit 1180.

[0152] Also, when a touch operation on the spatially floating image 3 by the user 230 is detected by the air operation detection sensor 1351, the color of the image light forming the spatially floating image 3 may be changed. For example, the color of the light emitted from the light source 1331 composed of a multicolor LED light source or the like may be changed. As an example, when no touch operation by the user 230 is detected, the display color of the spatially floating image 3 may be set to green, and while a touch operation by the user 230 is detected, the display color of the spatially floating image 3 may be changed from green to red.

[0153] <<Block diagram of the internal configuration of the spatially floating image display device>> FIG. 20 is a block diagram showing an example of the internal configuration of the spatial floating image display device 1000A. Next, the internal configuration of the spatial floating image display device 1000A according to the second embodiment, particularly the internal configuration of the spatial image display device 1300, will be described with reference to the block diagram of FIG. 20. In FIG. 20, the same components as those of the spatial floating image display device 1000 according to the first embodiment shown in FIG. 3 are denoted by the same reference numerals, and redundant descriptions are omitted. Also, in FIG. 20, the illustration of the optical element 1333 is omitted.

[0154] As shown in FIG. 20, the spatial floating image display device 1000A of the second embodiment includes a spatial image display device 1300. In FIG. 20, one spatial image display device 1300 is shown, but as described above, the spatial floating image display device 1000A of the second embodiment includes three spatial image display devices 1300.

[0155] The spatial image display device 1300 includes a retroreflective portion 1101 corresponding to the retroreflective plate 5 and a mask display unit 1310. The mask display unit 1310 includes a light source 1331 and a light guide 1332 that constitute the light source device 1330, and a mask member 1320. Further, the spatial image display device 1300 includes a power supply 1106, an external power input interface 1111, an operation input unit 1107, a nonvolatile memory 1108, a memory 1109, a control unit 1110, an air operation detection sensor 1351, an air operation detection unit 1350, and the like. Note that the change in the display color of the above-described spatial floating image 3 is executed by the control unit 1110 based on, for example, the detection result of the air operation detection sensor 1351.

[0156] In addition to the spatial image display device 1300, the spatial floating image display device 1000A may further include 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, and the like. The control unit 1110 can also change the display color of the spatial floating image 3 based on the signals input from the video signal input unit 1131 or the communication unit 1132.

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

[0158] As described above, according to the configuration of the spatial floating image display device 1000A according to the second embodiment, the aerial floating image 3 which is a still image such as a push button can be displayed with a relatively simple structure. Accordingly, the spatial floating image display device 1000A can be miniaturized, and the cost can also be reduced.

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

[0160] For example, as shown in FIG. 21, when the spatial floating image display device 1000A is arranged close to the wall W1, each spatial image display device 1300 may be arranged in the housing 1190 such that the emission direction of the image light, that is, the direction of the principal ray L1 of the image light (the direction of the optical axis) is inclined by a predetermined angle φ with respect to the wall surface of the wall W1. In other words, each spatial image display device 1300 may be arranged in the housing 1190 such that the direction of the principal ray L1 of the spatial floating image 3 is inclined by a predetermined angle φ with respect to the y direction.

[0161] In this example, the transparent member 100 is continuously provided along the x direction over the region facing the three spatial image display devices 1300. That is, the transparent member 100 is provided in common for the three spatial image display devices 1300. Of course, the transparent member 100 may be provided independently for each spatial image display device 1300.

[0162] Also, in the example shown in FIG. 21, each spatial image display device 1300 is arranged in a row along the x direction in a state inclined by a predetermined angle φ with respect to the y direction. That is, the plurality of spatial floating images 3 are inclined by a predetermined angle φ with respect to the y direction and arranged in a row along the x direction. Note that the spatial image display device 1300 is configured to be rotatable horizontally within the housing 1190. The predetermined angle φ by which the spatial floating image 3 is inclined can be appropriately adjusted by rotating the spatial image display device 1300.

[0163] Thereby, even when the spatial floating image display device 1000A is installed near the wall W1 and the user 230 has to view the spatial floating image 3 in an oblique direction with respect to the front surface 1190a of the housing 1190, the user 230 can easily view the spatial floating image 3. That is, even when the line of sight 230E of the user 230 has to intersect the y direction, the user 230 can easily view the spatial floating image 3.

[0164] Note that the spatial 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 plurality of spatial floating images 3 may be inclined by a predetermined angle φ with respect to the y direction and arranged in a row along the direction orthogonal to the direction of the principal ray L1 of the light forming the spatial floating image 3. In this case, it is preferable that the front surface 1190a of the housing 1190 is also formed along the direction orthogonal to the principal ray L1. The transparent member 100 is also preferably formed along the direction orthogonal to the principal ray L1. Thereby, the plurality of spatial floating images 3 can be favorably formed outside the transparent member 100.

[0165] In addition, in the second embodiment described above, as the spatial floating image display device 1000A, a configuration in which a plurality of spatial image display devices 1300 are arranged side by side in the horizontal direction is exemplified. However, the arrangement direction of the spatial image display devices 1300 is not particularly limited. For example, as shown in FIG. 23, a plurality of spatial image display devices 1300 may be arranged side by side in a row along the vertical direction (z direction). The plurality of spatial floating images 3 may be displayed along the vertical direction (z direction). Of course, the plurality of spatial floating images 3 may be arranged side by side in an oblique direction. For example, a plurality of spatial image display devices 1300 may be arranged side by side in an oblique direction intersecting the vertical direction (z direction) as an example.

[0166] <Modification Example 1 of Embodiment 2> FIG. 24 is a top view schematically showing the internal configuration of the spatial image display device according to Modification Example 1 of Embodiment 2. FIG. 25 is a plan view showing an example of the spatial floating image according to Modification Example 1 of Embodiment 2. FIG. 26 is a top view schematically showing another example of the internal configuration of the spatial image display device according to Modification Example 1 of Embodiment 2. In the drawings, the same members as those in the above-described Embodiment 2 are denoted by the same reference numerals, and redundant descriptions are omitted.

[0167] As shown in FIG. 24, each spatial image display device 1300 constituting the spatial floating image display device 1000A includes mirrors 1360A and 1360B as reflecting members on both side portions of the retroreflective plate 5. The mirrors 1360A and 1360B are collectively referred to as the mirror 1360. These mirrors 1360 are respectively provided outside both ends of the retroreflective plate 5 in the left-right direction (x direction) as viewed from the user 230. Thereby, the user 230 can more easily visually recognize the spatial floating image 3.

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

[0169] Therefore, when the mirror 1360 is not provided, the video light (light rays) emitted from near the end of the mask member 1320 in the x-direction is not incident on the retroreflective plate 5 as indicated by the dotted arrows in FIG. 24, and travels outside the retroreflective plate 5 in the D1 direction or the D2 direction. Thus, for example, when the user 230 tries to view both ends of the spatially floating image 3 in an oblique direction from near the center of the retroreflective plate 5 in the x-direction, it may be difficult to visually recognize the spatially floating image 3. In other words, when trying to view both ends of the spatially floating image 3 from near the center of the retroreflective plate 5 in the x-direction and the line of sight 230E of the user 230 intersects the y-direction as shown in FIG. 24, there is a risk that it will be difficult to visually recognize the spatially floating image 3.

[0170] On the other hand, when the mirror 1360 is provided, the video light emitted from near the end of the mask member 1320 in the x-direction is reflected by the mirror 1360 and incident on the retroreflective plate 5 as indicated by the solid arrows in FIG. 24. Further, the video light emitted from the retroreflective plate 5 is reflected again by the mirror 1360 to form the spatially floating image 3.

[0171] Therefore, even when the user 230 tries to view both ends of the spatially floating image 3 in an oblique direction from near the center of the retroreflective plate 5 in the x-direction, that is, even when the line of sight 230E of the user 230 intersects the y-direction, it becomes easier to visually recognize the spatially floating image 3. In other words, the viewing angle of the spatially floating image 3 can be expanded. For example, as shown in FIG. 25, it is particularly effective when light is emitted from near both ends in the x-direction of the mask member 1320, such as when the transmissive portion 1321 of the mask member 1320 is formed up to near both ends in the x-direction.

[0172] Note that these mirrors 1360 are preferably 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. Therefore, the mirrors 1360 are also preferably arranged along the y direction. Thereby, the visibility of the spatial floating image 3 by the user 230 is more reliably improved. Incidentally, if the deviation between the orientation of the surface of the mirror 1360 and the orientation of the chief ray L1 of the image light is large, there is a risk that the spatial floating image 3 becomes a double image and the visibility deteriorates in the vicinity of the end portions in the x direction.

[0173] Also, these mirrors 1360 are preferably provided so as to protrude to the outside of the member 100 that is transparent in the y direction. In particular, the mirrors 1360 are preferably continuously provided from the mask member 1320 to the position corresponding to the spatial floating image 3 in the y direction. Thereby, the image light emitted from the vicinity of both end portions in the x direction of the mask member 1320 is more reliably reflected by the mirrors 1360. As a result, the user 230 can more easily view the spatial floating image 3.

[0174] Note that in this example, the configuration in which the mirrors 1360 are provided outside both end portions 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 mirrors 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 portion of the spatial 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 the wall W2 exists on the left side of the spatial floating image display device 1000A, the situation where the user 230 views the vicinity of the right end portion of the spatial floating image 3 from the left outside of the spatial floating image display device 1000A is unlikely to occur. Therefore, by providing the mirror 1360 only outside the left end portion of the retroreflector 5, the visibility of the spatial floating image 3 by the user 230 can be improved as described above.

[0176] <Modification Example 2 of Example 2> FIG. 27 is a side view schematically showing the internal configuration of the spatial image display device according to Modification Example 2 of Example 2. FIG. 28 is a side view schematically showing another example of the internal configuration of the spatial image display device according to Modification Example 2 of Example 2. FIG. 29 is a front view for explaining another example of the spatial floating video display device according to Modification Example 2 of Example 2. In the figures, the same members as those in the above-described Example 2 are denoted by the same reference numerals, and redundant descriptions are omitted.

[0177] The spatial floating video display device 1000A shown in FIG. 27 is an example further including a contact detector that detects contact of the finger of the user 230 with the transparent member 100 which is a protective plate. Specifically, in the spatial floating video display device 1000A, the transparent member 100 is configured to be movable in the y direction by a predetermined amount. For example, when the user 230 presses the transparent member 100 with a finger, the transparent member 100 is configured to move by a predetermined amount in the y direction.

[0178] Inside this transparent member 100, that is, on the side of the retroreflective plate 5, a movement detector for detecting the movement of the transparent member 100 is provided. As an example, inside the transparent member 100, a push switch 1370 as a movement detector is provided at a position where it comes into contact when the transparent member 100 is pushed and moved. When the transparent member 100 moves and the push switch 1370 is pushed by the transparent member 100, the movement of the transparent member 100 is detected.

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

[0180] In such a configuration, when the user 230 touches the floating image 3 in space, even if the touch operation is not detected by the air operation detection sensor 1351, for example, when the transparent member 100 is pushed, the touch operation by the user 230 can be surely detected.

[0181] The spatial floating image display device 1000A shown in FIG. 28 is an example including a capacitance sensor 1380 provided on the transparent member 100 as a contact detector for detecting contact of the finger of the user 230 with respect to the transparent member 100 which is a protection plate.

[0182] As an example, the capacitance sensor 1380 is provided over the entire surface on the surface of the transparent member 100 on the user 230 side. The capacitance sensor 1380 only needs to be able to detect contact of the finger of the user 230 with respect to the transparent member 100 when the user 230 touches the floating image 3 in space, and its arrangement and formation range are not particularly limited. The capacitance sensor 1380 may be provided, for example, only in a region corresponding to the floating image 3 in space of the transparent member 100.

[0183] Furthermore, when the spatial floating image display device 1000A shown in FIG. 28 detects contact of the finger of the user 230 with respect to the transparent member 100 by the capacitance sensor 1380 which is a contact detector, it includes a vibration generator 1390 that generates vibration. In this example, the vibration generator 1390 is provided inside the transparent member 100, that is, on the side of the retroreflective plate 5. The vibration generator 1390 is provided in a state of being in contact with the lower part of the transparent member 100.

[0184] Then, when contact of the finger of the user 230 with respect to the transparent member 100 is detected by the capacitance sensor 1380, the vibration generator 1390 vibrates. In this example, when the touch operation of the floating image 3 in space by the user 230 is detected by the air operation detection sensor 1351 and contact of the finger of the user 230 with respect to the transparent member 100 is detected by the capacitance sensor 1380, the vibration generator 1390 vibrates. The vibration generated by the vibration generator 1390 is transmitted to the finger of the user 230 through the transparent member 100.

[0185] As a result, the user 230 can surely recognize that the touch operation on the spatial floating image 3 has been detected. Therefore, even if the user 230 is, for example, a visually impaired person or the like, the user 230 can surely recognize that the spatial floating image 3 has been touched and operated.

[0186] Furthermore, for example, as shown in FIG. 29, Braille 1400 regarding the content of the spatial floating image 3 may be provided below the area where the spatial floating image 3 of the transparent member 100 functioning as a protective plate is displayed. Thereby, the user 230 who is a visually impaired person can correctly recognize the content of the spatial floating image 3. In this example, the Braille 1400 is provided below each spatial floating image 3, but it goes without saying that the position where the Braille 1400 is provided is not particularly limited.

[0187] In the technology according to this embodiment, by displaying high-resolution and high-brightness video information in a spatially floating state, for example, it becomes possible for a user to operate without feeling anxiety about the contact infection of infectious diseases. If the technology according to this embodiment is used in a system used by an unspecified number of users, it is possible to reduce the risk of contact infection of infectious diseases and provide a non-contact user interface that can be used without feeling anxiety. Thereby, it contributes to "3 - Good health and well-being for all" of the Sustainable Development Goals (SDGs) advocated by the United Nations.

[0188] In addition, in the technology according to this embodiment, by reducing the divergence angle of the emitted video light and further aligning it with a specific polarization, only the regular reflected light is efficiently reflected from the retroreflective plate, resulting in high light utilization efficiency and enabling the acquisition of bright and clear floating images in space. According to the technology of this embodiment, it is possible to provide a non-contact user interface with excellent usability that can significantly reduce power consumption. This contributes to the United Nations' Sustainable Development Goals (SDGs): "Build the foundation for industry and technological innovation" and "Build sustainable cities."

[0189] As described in detail above for various embodiments, however, the present invention is not limited to only the above-described embodiments and includes various modifications. For example, the above-described embodiments have described the entire system in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Also, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is possible to add, delete, or replace other configurations for a part of the configuration of each embodiment.

Description of Reference Numerals

[0190] 1... represents a device, 2, 5... retroreflective plate (retroreflective sheet), 3... spatial image (spatial floating image), 105... windshield, 100... transparent member, 13... light source device, 54... light direction conversion panel, 102, 202... LED substrate, 203... light guide, 205, 271... reflective sheet, 206, 270... retardation plate, 230... user, 335... video light control sheet, 1000, 1000A... spatial floating image display device, 1110... control unit, 1160... video control unit, 1180... imaging unit, 1102... video display unit, 1300... spatial image display device (spatial image display unit), 1310... mask display unit, 1320... mask member, 1321... transmission part, 1322... low transmission part, 1323... non-transmission part, 1330... light source device, 1331... light source, 1332... light guide, 1333... optical element, 1350... air operation detection unit, 1351... air operation detection sensor

Claims

1. An airborne floating image display device, a light source device, a mask member disposed such that light emitted from the light source device is incident in an oblique direction and having a transmission portion of a predetermined shape that transmits the incident light, a retroreflective member that reflects the light transmitted through the mask member and displays an airborne floating image, which is a real image, in the air by the reflected light, and an operation detector that detects an operation of the airborne floating image by a user. An airborne floating image display device.

2. The airborne floating image display device according to claim 1, comprising an image light control sheet disposed between the mask member and the retroreflective member and transmitting the light transmitted through the mask member. An airborne floating image display device.

3. The airborne floating image display device according to claim 1, wherein the light source device comprises a light source and a light guide that guides the light emitted from the light source to be incident on the mask member in an oblique direction. An airborne floating image display device.

4. The airborne floating image display device according to claim 3, wherein the light source device further comprises an optical element disposed between the light source and the light guide and reducing the diffusion angle of the light emitted from the light source. An airborne floating image display device.

5. The airborne floating image display device according to claim 3, wherein light is emitted downward obliquely by the light source, the airborne floating image is displayed by light traveling upward obliquely by the retroreflective member, and the light source is disposed above the light guide and directed toward the light guide. An airborne floating image display device.

6. The airborne floating image display device according to claim 1, comprising a reflective member disposed along the direction of the principal ray of the light emitted from the light source device outside at least one end of the retroreflective member. An airborne floating image display device.

7. The airborne floating image display device according to claim 6, wherein the reflective members are respectively disposed outside both ends of the retroreflective member. An airborne floating image display device.

8. The airborne floating image display device according to claim 6, wherein the reflective member is continuously provided from the mask member to a portion corresponding to the airborne floating image. An airborne floating image display device.

9. The airborne floating image display device according to claim 1, comprising a protective plate disposed between the retroreflective member and the airborne floating image and formed of a transparent material, wherein the airborne floating image is displayed by the light transmitted through the protective plate. An airborne floating image display device.

10. An airborne floating image display device according to claim 9, further comprising a contact detector for detecting contact of the user's finger with the protection plate, airborne floating image display device.

11. An airborne floating image display device according to claim 10, wherein the contact detector detects contact of the protection plate with the contact detector, and when there is contact of the protection plate with the contact detector, determines that the user's finger has contacted the protection plate, airborne floating image display device.

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

13. An airborne floating image display device according to claim 11, comprising a vibration generator attached to the protection plate and generating vibration when contact of the user's finger with the protection plate is detected by the contact detector, airborne floating image display device.

14. An airborne floating image display device according to claim 1, comprising a plurality of mask display units including the light source device and the mask member, airborne floating image display device.

15. An airborne floating image display device according to claim 1, wherein the light source device is configured to emit light of a plurality of colors, and changes the color of the emitted light when an operation of the airborne floating image by the user is detected by the operation detector, airborne floating image display device.

16. An airborne floating image display device according to claim 1, wherein the airborne floating image is a still image of a push button, airborne floating image display device.

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