WO2025126632A1 - Aerial floating image display apparatus - Google Patents

Abstract

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

Description

Floating-air image display device

The present invention relates to a floating image display device.

　Airborne information display technology is disclosed, for example, in Patent Document 1.

JP 2019-128722 A

However, the disclosure in Patent Document 1 does not sufficiently consider configurations for achieving practical brightness and quality for the levitating image, or configurations for allowing users to enjoy viewing the levitating image more.

The object of the present invention is to provide a more suitable floating image display device.

In order to solve the above problem, for example, the configuration described in the claims is adopted. The present application includes multiple means for solving the above problem, but one example is a floating image display device that includes a light source device, a mask member that is arranged so that light emitted from the light source device is incident at an oblique angle and has a transparent portion of a predetermined shape that transmits the incident light, a retroreflective member that is arranged parallel to the mask member and reflects the light that has transmitted through the transparent portion and displays a floating image that is a real image in the air using the reflected light, and an operation detector that detects operation of the floating image by a user.

The present invention makes it possible to realize a more suitable floating image display device. Other issues, configurations, and advantages will be made clear in the description of the embodiments below.

1 is a diagram showing an example of a usage form of a space floating image display device according to an embodiment of the present invention; 1 is a diagram showing an example of a main part configuration and a retroreflection part configuration of a floating-in-the-air image display device according to an embodiment of the present invention; 1 is a projection diagram of a retroreflector constituting a floating-in-the-air image display device according to an embodiment of the present invention; FIG. 2 is a top view of a retroreflector constituting a floating-in-the-air image display device according to an embodiment of the present invention. FIG. 2 is a perspective view showing a corner reflector constituting a retroreflector constituting a floating-in-the-air image display device according to an embodiment of the present invention. FIG. 2 is a top view showing a corner reflector constituting a retroreflector constituting a floating-in-the-air image display device according to an embodiment of the present invention. 1 is a side view showing a corner reflector constituting a retroreflector constituting a floating-in-the-air image display device according to an embodiment of the present invention; FIG. 1 is a diagram showing an example of the configuration of a space floating image display device according to an embodiment of the present invention. FIG. 1 is a diagram showing an example of a configuration of a space floating image display device according to an embodiment of the present invention. FIG. 1 is a diagram showing an example of a configuration of a space floating image display device according to an embodiment of the present invention. FIG. 1 is a diagram showing an example of a configuration of a space floating image display device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing an example of a specific configuration of a light source device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing an example of a specific configuration of a light source device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing an example of a specific configuration of a light source device according to an embodiment of the present invention. 1 is a layout diagram showing a main part of a space floating image display device according to an embodiment of the present invention; 1 is a cross-sectional view showing a configuration of a display device according to an embodiment of the present invention. 1 is a cross-sectional view showing a configuration of a display device according to an embodiment of the present invention. 1 is an explanatory diagram for explaining a light source diffusion characteristic of an image display device according to an embodiment of the present invention. 1 is an explanatory diagram for explaining the diffusion characteristics of a video display device according to an embodiment of the present invention; 1 is a front view showing an example of a space floating image display device according to an embodiment of the present invention; 1 is a top view showing an example of the arrangement of a spatial image display device according to an embodiment of the present invention. 1 is a side view showing a schematic example of an internal configuration of a spatial image display device according to an embodiment of the present invention; 1A and 1B are diagrams illustrating an example of a mask member according to an embodiment of the present invention. FIG. 2 is a diagram illustrating an example of a floating image in space according to an embodiment of the present invention. 1 is a side view showing a schematic example of an internal configuration of a mask display unit according to an embodiment of the present invention; 1 is a diagram showing an example of an image light control sheet according to an embodiment of the present invention; 1 is a block diagram showing an example of the configuration of a space floating image display device according to an embodiment of the present invention; 11 is a top view showing another example of the arrangement of the spatial image display device according to an embodiment of the present invention. FIG. 11 is a top view showing another example of the arrangement of the spatial image display device according to an embodiment of the present invention. FIG. 11 is a front view showing another example of the arrangement of the space floating projection device according to an embodiment of the present invention. FIG. FIG. 11 is a top view diagrammatically illustrating another example of the aerial image display device according to an embodiment of the present invention. 11A and 11B are diagrams showing another example of a mask member according to an embodiment of the present invention. FIG. 11 is a top view diagrammatically illustrating another example of the aerial image display device according to an embodiment of the present invention. 11 is a side view showing a schematic diagram of another example of the internal configuration of the spatial image display device according to the embodiment of the present invention. FIG. 11 is a side view showing a schematic diagram of another example of the internal configuration of the spatial image display device according to the embodiment of the present invention. FIG. FIG. 11 is a front view illustrating another example of the space floating image display device according to an embodiment of the present invention.

Below, an embodiment 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 embodiment, and various changes and modifications can be made by those skilled in the art within the scope of the technical ideas disclosed in this specification. Furthermore, in all drawings used to explain the present invention, parts having the same function are given the same reference numerals, and repeated explanations of such parts may be omitted.

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

According to the following embodiment, for example, a suitable image display device can be realized in a bank ATM, a ticket vending machine at a station, a digital signage, etc. For example, currently, a touch panel is usually used in a bank ATM, a ticket vending machine at a station, etc., but a transparent glass surface or a light-transmitting plate material can be used to display high-resolution image information in a floating state on the glass surface or the light-transmitting plate material. At this time, by making the divergence angle of the emitted image light small, i.e., an acute angle, and further aligning it with a specific polarization, only the normal reflected light is efficiently reflected by the retroreflector, so that the light utilization efficiency is high, and ghost images that occur in addition to the main floating image, which was a problem in the conventional retroreflection method, can be suppressed, and a clear floating image can be obtained. In addition, a device including the light source of this embodiment can provide a new and highly usable floating image display device (floating image display system) that can significantly reduce power consumption. In addition, for example, a floating image display device for a vehicle that can display a floating image in a one-way manner, which is visible inside and/or outside the vehicle, can be provided.
Example 1

<Example of usage of the space floating image display device>
FIG. 1 is a diagram showing an example of the use of a space-floating image display device according to an embodiment of the present invention, and is a diagram showing the overall configuration of the space-floating image display device according to this embodiment. The specific configuration of the space-floating image display device will be described in detail using FIG. 2 and the like, but light with a narrow-angle directional characteristic and specific polarization is emitted from the image display device 1 as an image light beam, and is once incident on the retroreflector 2 after reflection in the optical system in the space-floating image display device, and is retroreflected and transmitted through a transparent member 100 (glass, etc.), forming a real aerial image (space-floating image 3) on the outside of the glass surface. In the following embodiments, the retroreflector 2 (retroreflector) is used as an example of the retroreflector. However, the retroreflector 2 of the present invention is not limited to a flat plate, and is used as an example of a concept including a sheet-like retroreflector attached to a flat or non-flat member, and an entire assembly in which a sheet-like retroreflector is attached to a flat or non-flat member. Furthermore, since the light rays reflected by the retroreflector 2 have the optical property of forming an image, the retroreflector 2 may be expressed as an imaging optical member or an imaging optical plate.

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

In Figure 1, the inside of the window glass 105 (inside the store) is shown in the depth direction, with the outside (e.g., the sidewalk) in the foreground. On the other hand, by providing the window glass 105 with a means for reflecting a specific polarized wave, it is possible to reflect the wave and form an aerial image at a desired position inside the store.

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

FIG. 2A is a diagram showing an example of the main components and retroreflective components of a spatial floating image display device according to one embodiment of the present invention. A display device 1 that emits image light is provided in an oblique direction of a transparent member 100 such as glass. The display device 1 includes a liquid crystal display panel 11 and a light source device 13 that generates light.

The chief ray 9020, which represents the light beam emitted from the display device 1, travels toward the retroreflector 5 and is incident on the retroreflector 5 at an incident angle α. The incident angle α may be, for example, 45°. However, the incident angle α is not limited to 45°, and may be, for example, 45°±15°.

The retroreflector 5 is an optical element that has the optical property of retroreflecting light rays in at least some directions. In addition, since the reflected light rays have the optical property of forming an image, the retroreflector 5 may also be referred to as an imaging optical element or imaging optical plate.

The specific configuration of the retroreflector 5 will be described in detail using Figures 2B and 2C, etc., but the retroreflector 5 causes the main ray 9020 to travel in the z direction while being retroreflected in the x and y directions. As a result, the reflected ray 9021 travels along an optical path that is mirror-symmetrical to the main ray 9020 with the retroreflector 5 as the reference, in a direction away from the retroreflector 5, passes through the transparent member 100, and forms the floating-in-space image 3 as a real image on the imaging plane.

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

2B and 2C, an example of the configuration of the retroreflector 5 will be described. The retroreflector 5 has a configuration in which multiple corner reflectors 9040 are arranged in an array on the surface of a transparent member 50. This may be called a corner reflector array or a multi-surface reflector array. The specific configuration of the corner reflector 9040 will be described in detail using Figures 2D, 2E, and 2F. Light rays 9111, 9112, 9113, and 9114 emitted from a light source 9110 are reflected twice by two mirror surfaces 9041 and 9042 of the corner reflector 9040, becoming reflected light rays 9121, 9122, 9123, and 9124. This double reflection is a retroreflection that turns back in the same direction as the incident direction (travels in a direction rotated 180 degrees) in the x and y directions, and a regular reflection in which the incident angle and reflection angle match due to total reflection in the z direction.

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

Next, the configuration and effect of the corner reflector 9040 that constitutes the retroreflector 5 will be described with reference to Figures 2D, 2E, and 2F. The corner reflector 9040 is a rectangular parallelepiped with only two specific faces being mirror surfaces 9041 and 9042, and the other four faces being made of transparent materials. The retroreflector 5 has a configuration in which the corner reflectors 9040 are arrayed so that the corresponding mirror surfaces face in the same direction.

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

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

As a result of the above, the light rays incident on the corner reflector 9040 undergo retroreflection with inverted optical paths in the x and y directions, and undergo regular reflection due to total reflection in the z direction. Considering the retroreflector 5, similar reflections occur in each optical path, so that an image is formed at a point symmetrical with respect to the z-axis direction due to the inverted optical paths that are convergent in the x and y directions.

In the optical system of FIG. 2A, the retroreflector 5 has retroreflection properties in two axial directions, and is specularly reflective in the other axial direction. As a result, when a diffusive incident light beam is incident on the retroreflector 5, the convergent reflected light beam reflected by the corner reflector array travels toward the side of the retroreflector 5 opposite the side where the light source of the incident light is located. This convergent reflected light beam forms an image in the air, forming the floating image 3.

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

In other words, the diffusive incident light beam is converted into a convergent reflected light beam by reflection on the retroreflector 5, but in the normal direction to the plate-shaped surface of the retroreflector 5, this light beam travels as if passing through the retroreflector 5. Here, the diffusive incident light beam that enters the retroreflector 5 and the convergent reflected light beam that exits from the retroreflector 5 are geometrically symmetrical with respect to the plate-shaped surface of the retroreflector 5.

The resolution of the floating image formed by the light from the video output unit 10 depends heavily on the diameter D and pitch P (not shown) of the retroreflective portion of the retroreflector 5 shown in Figures 2B and 2C, in addition to the resolution of the liquid crystal display panel 11. For example, when using a 7-inch WUXGA (1920 x 1200 pixels) liquid crystal display panel, even if one pixel (one triplet) is about 80 μm, if the diameter D of the retroreflective portion is 240 μm and the pitch P is 300 μm, one pixel of the floating image in space will be equivalent to 300 μm. As a result, the effective resolution of the floating image in space will be reduced to about 1/3.

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

The shape of the retroreflector (imaging optical plate) according to this embodiment is not limited to the above example. It may have various shapes that realize retroreflection. Specifically, it may be various cubic corner bodies, corner reflector arrays, slit mirror arrays, two-sided corner reflector arrays, polyhedral reflector arrays, or shapes in which a combination of their reflective surfaces is periodically arranged. Alternatively, a capsule lens type retroreflection element in which glass beads are periodically arranged may be provided on the surface of the retroreflection plate of this embodiment. The detailed configuration of these retroreflection elements can be achieved by using existing technology, so a detailed description will be omitted. Specifically, it is possible to use the technology disclosed in JP2017-33005A, JP2019-133110A, JP2017-67933A, WO2009/131128A, etc.

In the optical system of FIG. 2A, the image light emitted from the display device 1 can be in any polarization state. It does not matter whether it is S-polarized or P-polarized.

As explained above, the optical system of FIG. 2A can produce a more suitable floating image in space.

The optical system of FIG. 2A described above can provide brighter, higher quality floating images.

<<Block diagram of the internal structure of the floating image display device>>

Next, we will explain the block diagram of the internal configuration of the space floating image display device 1000. Figure 3 is a block diagram showing an example of the internal configuration of the space floating image display device 1000.

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

The components of the space floating image display device 1000 are arranged in a housing 1190. Note that the imaging unit 1180 and the aerial operation detection sensor 1351 shown in FIG. 3 may be provided on the outside of the housing 1190.

The retroreflective portion 1101 in FIG. 3 corresponds to the retroreflective plate 5 in FIG. 2A. The retroreflective portion 1101 retroreflects the light modulated by the image display portion 1102. The light reflected from the retroreflective portion 1101 is output to the outside of the space-floating image display device 1000 to form the space-floating image 3.

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

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

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

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

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

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

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

The aerial operation detection unit 1350 acquires a sensing signal from the aerial operation detection sensor 1351, and performs operations such as determining whether or not the finger of the user 230 has touched an object in the floating-in-space image 3 and calculating the position (contact position) at which the finger of the user 230 has touched the object based on the sensing signal. The aerial operation detection unit 1350 is configured with a circuit such as an FPGA (Field Programmable Gate Array). Some of the functions of the aerial operation detection unit 1350 may also be realized by software, for example, by a spatial operation detection program executed by the control unit 1110.

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

Furthermore, the aerial operation detection sensor 1351 and the aerial operation detection unit 1350 may be provided separately. This makes it possible to build a system in which the air-floating image display device 1000, which does not have an aerial operation detection function, is the main body, and only the aerial operation detection function can be added as an option. Also, a configuration in which only the aerial operation detection sensor 1351 is a separate unit, and the aerial operation detection unit 1350 is built into the air-floating image display device 1000, may be used. In cases where it is desired to more freely position the aerial operation detection sensor 1351 relative to the installation position of the air-floating image display device 1000, a configuration in which only the aerial operation detection sensor 1351 is a separate unit is advantageous.

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

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

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

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

The imaging unit 1180 may also capture an image of the face of the user 230 operating the floating image 3, and the control unit 1110 may perform an identification process for the user 230. The imaging unit 1180 may also capture an image of the user 230 operating the floating image 3 and a range including the user 230 operating the floating image 3 and the surrounding area of the user 230, in order to determine whether or not another person is standing around or behind the user 230 operating the floating image 3 and peeking at the user's operation of the floating image 3.

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

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

Alternatively, an analog video input interface such as analog RGB or composite video may be provided. The audio signal input unit 1133 connects an external audio output device and inputs audio data. The audio signal input unit 1133 may be configured as an HDMI standard audio input interface, an optical digital terminal interface, a coaxial digital terminal interface, or the like. In the case of an HDMI standard interface, the video signal input unit 1131 and the audio signal input unit 1133 may be configured as an interface in which a terminal and a cable are integrated. The audio output unit 1140 is capable of outputting audio based on the audio data input to the audio signal input unit 1133. The audio output unit 1140 may be configured as a speaker.

The audio output unit 1140 may also output built-in operation sounds or error warning sounds. Alternatively, the audio output unit 1140 may be configured to output a digital signal to an external device, like the Audio Return Channel function defined in the HDMI standard. The microphone 1139 is a microphone that picks up sounds around the space floating image display device 1000, converts them into a signal, and generates an audio signal. The microphone may be configured to record a person's voice, such as a user's voice, and the control unit 1110, described later, may perform voice recognition processing on the generated audio signal to obtain text information from the audio signal.

Non-volatile memory 1108 stores various data used by the space floating image display device 1000. Data stored in non-volatile memory 1108 includes, for example, data for various operations to be displayed on the space floating image 3, display icons, data for objects to be operated by user operations, layout information, etc. Memory 1109 stores image data to be displayed as the space floating image 3, data for controlling the device, etc.

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

The communication unit 1132 communicates with external devices, external servers, etc., via a wired or wireless communication interface. If the communication unit 1132 has a wired communication interface, the wired communication interface may be configured, for example, as an Ethernet standard LAN interface. If the communication unit 1132 has a wireless communication interface, the interface may be configured, for example, as a Wi-Fi communication interface, a Bluetooth communication interface, or a mobile communication interface such as 4G or 5G. Various types of data, such as video data, image data, and audio data, are sent and received by communication via the communication unit 1132.

Furthermore, the removable media interface 1134 is an interface for connecting a removable recording medium (removable media). The removable recording medium (removable media) may be composed of a semiconductor 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 is capable of reading out 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, and the like recorded on the removable recording medium are output as a floating image 3 via the image display unit 1102 and the retroreflection unit 1101.

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

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

Layout information such as display icons and objects displayed as the floating-in-space image 3, and various metadata information related to the objects are also recorded in the storage unit 1170. The audio data recorded in the storage unit 1170 is output as audio from the audio output unit 1140, for example.

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

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

The video control unit 1160 may also control image processing of the video signal input from the video signal input unit 1131 and the video signal to be stored in the memory 1109. Examples of image processing include scaling processing to enlarge, reduce, or deform an image, brightness adjustment processing to change the brightness, contrast adjustment processing to change the contrast curve of an image, and Retinex processing to break down an image into light components and change the weighting of each component.

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

The attitude sensor 1113 is a sensor consisting of a gravity sensor or an acceleration sensor, or a combination of these, and can detect the attitude in which the space-floating image display device 1000 is installed. Based on the attitude detection result of the attitude sensor 1113, the control unit 1110 may control the operation of each connected unit. For example, if an undesirable attitude is detected as the user's usage state, control may be performed to stop the display of the image being displayed on the image display unit 1102 and display an error message to the user. Alternatively, if the attitude sensor 1113 detects that the installation attitude of the space-floating image display device 1000 has changed, control may be performed to rotate the display direction of the image being displayed on the image display unit 1102.

As explained so far, the space-floating image display device 1000 is equipped with various functions. However, the space-floating image display device 1000 does not need to have all of these functions, and any configuration is acceptable as long as it has the function of forming the space-floating image 3.

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

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

Even in the example of a floating-in-space image display device that employs the optical system of FIG. 2A, the floating-in-space image 3 is imaged in front of the transparent member 100, and the operation of the floating-in-space image 3 by the user's finger can be detected using the sensing light of the mid-air operation detection sensor 1351 that is positioned behind the transparent member 100 as seen by the user.

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

In other words, in FIG. 4B, the floating-in-space image display device 1000 has a transparent member 100 placed on the top surface of the device. The floating-in-space image 3 is formed above the surface of the transparent member 100 of the floating-in-space image display device 1000. The light of the floating-in-space image 3 travels diagonally upward. If the mid-air operation detection sensor 1351 is provided as shown in the figure, it can detect the operation of the floating-in-space image 3 by the finger of the user 230.

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

4C is a diagram showing an example of the configuration of a space-floating image display device. The space-floating image display device 1000 shown in FIG. 4C is equipped with an optical system corresponding to the optical system of FIG. 2A. The space-floating image display device 1000 shown in FIG. 4C is installed vertically so that the surface on which the space-floating image 3 is formed faces the front of the space-floating image display device 1000 (toward the user 230). That is, in FIG. 4C, the space-floating image display device 1000 is installed with the transparent member 100 on the front side of the device (toward the user 230). The space-floating image 3 is formed on the user 230 side with respect to the surface of the transparent member 100 of the space-floating image display device 1000. The light of the space-floating image 3 travels diagonally upward. When the midair operation detection sensor 1351 is provided as shown in FIG. 4C, it is possible to detect the operation of the space-floating image 3 by the finger of the user 230. Here, as shown in FIG. 4C , the aerial operation detection sensor 1351 senses the finger of the user 230 from above, and can utilize the reflection of sensing light by the nail of the user 230 for touch detection. Generally, a nail has a higher reflectivity than the pad of a finger, so by configuring the aerial operation detection sensor 1351 in this way, the accuracy of touch detection can be improved.

The configuration of the space floating image display device shown in Figures 4A to 4C makes it possible to realize a user-friendly space floating image display device using the optical system shown in Figure 2A.

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

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

In addition, in FIG. 5, the display device 1 is configured to include a liquid crystal display panel 11, a light direction conversion panel 54 that controls the directional characteristics of the light beam emitted from the light source device 13, and a narrow-angle diffuser plate (not shown) as necessary. That is, polarizing plates are provided on both sides of the liquid crystal display panel 11, and image light of a specific polarization is emitted with the light intensity modulated by the image signal (see arrow 30 in FIG. 5). As a result, the desired image is projected as light of a specific polarization with high directivity (linearity) through the light direction conversion panel 54 toward the retroreflector 2, and after reflection by the retroreflector 2, it is transmitted toward the eyes of a monitor outside the store (space) to form a floating image 3. In addition, a protective cover 50 (see FIG. 6 and FIG. 7) may be provided on the surface of the above-mentioned light direction conversion panel 54.

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

Furthermore, the frame (not shown) of the liquid crystal display panel attached to the upper surface of the case of the light source device 13 is configured by attaching the liquid crystal display panel 11 attached to the frame, and further by attaching FPC (Flexible Printed Circuits) (not shown) electrically connected to the liquid crystal display panel 11. That is, the liquid crystal display panel 11, which is an image display element, generates a display image by modulating the intensity of transmitted light based on a control signal from a control circuit (image control unit 1160 in FIG. 3) constituting an electronic device together with the LED element 201, which is a solid light source. At this time, the generated image light has a narrow diffusion angle and contains only specific polarization components, so that a new image display device that is similar to a surface-emitting laser image source driven by an image signal is obtained. Note that, at present, it is technically and safety impossible to obtain a laser light beam of the same size as the image obtained by the above-mentioned display device 1 using a laser device. Therefore, in this embodiment, light similar to the above-mentioned surface-emitting laser image light is obtained from a light beam from a general light source equipped with an LED element, for example.

Next, the configuration of the optical system housed in the case of the light source device 13 will be described in detail with reference to Figure 6 and Figure 7.

Because Figures 6 and 7 are cross-sectional views, only one of the multiple LED elements 201 that make up the light source is shown, and this is converted into approximately collimated light by the shape of the light-receiving end surface 203a of the light guide 203. For this reason, the light-receiving part of the light guide end surface and the LED element are attached while maintaining a specified positional relationship.

The light guides 203 are each formed of a translucent resin such as acrylic. The LED light receiving surface at the end of the light guide 203 has a convex convex outer surface obtained by rotating a parabolic cross section, and at the top of the light guide 203, a concave portion is formed with a convex portion (i.e., a convex lens surface) in the center, and a convex lens surface protruding outward (or a concave lens surface recessed inward) is formed in the center of the flat surface (not shown). The outer shape of the light receiving part of the light guide to which the LED element 201 is attached is a parabolic shape that forms a conical outer surface, and is set within an angle range in which the light emitted from the LED element in the peripheral direction can be totally reflected inside, or a reflective surface is formed.

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

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

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

The light beam direction conversion means 204 described above emits the light beam propagated within the light guide toward the liquid crystal display panel 11 arranged approximately parallel to the light guide 203 (in a direction perpendicular to the front of the drawing) by using the shape of the light guide surface or by providing a portion with a different refractive index inside the light guide. At this time, if the relative brightness ratio between the brightness at the center of the screen and the brightness at the periphery of the screen is compared while facing the liquid crystal display panel 11 directly at the center of the screen and placing the viewpoint at the same position as the diagonal dimension of the screen, there is no practical problem if the relative brightness ratio is 20% or more, and if it exceeds 30%, it will be an even better characteristic.

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

Also, a film or sheet-like reflective polarizing plate 49 is provided on the light source light incidence surface (lower surface in the figure) of the liquid crystal display panel 11 corresponding to the light source device 13, and selectively reflects one side of the polarized wave (e.g. P wave) 212 of the natural light beam 210 emitted from the LED element 201. The reflected light is reflected again by the reflective sheet 205 provided on one surface (lower surface in the figure) of the light guide 203, and directed toward the liquid crystal display panel 11. Therefore, a retardation plate (lambda/4 plate) is provided between the reflective sheet 205 and the light guide 203 or between the light guide 203 and the reflective polarizing plate 49, and the reflected light beam is reflected by the reflective sheet 205 and passes through it twice to convert the reflected light beam from P polarized light to S polarized light, improving the efficiency of use of the light source light as image light. The image light beam whose light intensity has been modulated by the image signal in the liquid crystal display panel 11 (arrow 213 in FIG. 6) enters the retroreflector 2. After reflection from the retroreflector 2, a real image, a floating image in space, can be obtained.

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

Also, a film or sheet-like reflective polarizing plate 49 is provided on the light source light incidence surface (lower surface in the figure) of the liquid crystal display panel 11 corresponding to the light source device 13, and selectively reflects one side of the polarized wave (e.g., S wave) 211 of the natural light beam 210 emitted from the LED element 201. That is, in the example of FIG. 7, the selective reflection characteristic of the reflective polarizing plate 49 is different from that of FIG. 7. The reflected light is reflected by the reflective sheet 205 provided on one surface (lower surface in the figure) of the light guide 203 and heads toward the liquid crystal display panel 11 again. A retardation plate (lambda/4 plate) is provided between the reflective sheet 205 and the light guide 203 or between the light guide 203 and the reflective polarizing plate 49, and the reflected light beam is reflected by the reflective sheet 205 and passes through it twice to convert the reflected light beam from S polarized light to P polarized light, improving the utilization efficiency of the light source light as image light. The image light beam intensity-modulated by the image signal in the liquid crystal display panel 11 (arrow 214 in FIG. 7) enters the retroreflector 2. After reflection from the retroreflector 2, a real image, a floating image in space, can be obtained.

In the light source devices shown in Figures 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, the polarized component on one side is reflected by the reflective polarizing plate, so the theoretically obtainable 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. This results in high contrast performance. In fact, it was confirmed through experiments that the contrast performance of the displayed image was improved by more than 10 times. As a result, a high-quality image was obtained that was comparable to that of a self-luminous organic EL.

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

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

<Display Device Example 3>
Next, another example of the specific configuration of the display device 1 (Example 3 of the display device) will be described with reference to FIG. 9. The light source device of this display device 1 converts the divergent light flux of the light (mixture of P-polarized light and S-polarized light) from the LED into a substantially parallel light flux by the collimator 18, and reflects it toward the liquid crystal display panel 11 by the reflecting surface of the reflective light guide 304. The reflected light is incident on the reflective polarizing plate 49 arranged between the liquid crystal display panel 11 and the reflective light guide 304. The reflective polarizing plate 49 transmits light of a specific polarized wave (e.g., P-polarized light) and causes the transmitted polarized light to be incident on the liquid crystal display panel 11. Here, polarized waves other than the specific polarized wave (e.g., S-polarized light) are reflected by the reflective polarizing plate 49 and head toward the reflective light guide 304 again.

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

At this time, the light that re-enters the reflective polarizing plate 49 has passed through the λ/4 plate 270 twice, and therefore its polarization has been converted to a polarized wave (e.g., P-polarized light) 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. Note that, with regard to the polarization design related to the polarization conversion, it is also possible to configure the polarization inversely from the above explanation (reversing the S-polarized light and the P-polarized light).

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

The collimators 18 are each formed of a translucent resin such as acrylic or glass. The collimators 18 may have a cone-shaped outer periphery obtained by rotating a parabolic cross section. The collimator 18 may have a concave portion with a convex portion (i.e., a convex lens surface) formed in the center of the apex (the side facing the LED board 102). The collimator 18 has a convex lens surface protruding outward (or a concave lens surface recessed inward) in the center of the flat surface (the side opposite the apex). The parabolic surface forming the cone-shaped outer periphery of the collimator 18 is set within an angle range that allows the light emitted from the LED in the peripheral direction to be totally reflected therein, or a reflective surface is formed.

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

With this configuration, the collimator 18 focuses the light emitted from the LED, particularly the light emitted from the center, into parallel light by the convex lens surface that forms the outer shape of the collimator 18. Light emitted from other parts toward the periphery is reflected by the parabolic surface that forms the outer peripheral surface of the cone shape of the collimator 18, and is similarly focused into parallel light. In other words, with a collimator 18 that has a convex lens in its center and a parabolic surface formed on its periphery, it is possible to extract almost all of the light generated by the LED as parallel light, improving the efficiency of use of the generated light.

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

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

<Display Device Example 4>
Further, another example (display example 4) 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 which a diffusion sheet is used instead of the reflective light guide 304 in the light source device of the display device example 3. Specifically, two optical sheets (optical sheet 207A and optical sheet 207B) that convert the diffusion characteristics in the vertical direction and horizontal direction (front and back directions not shown in the figure) of the drawing are used on the light emission side of the collimator 18, and the light from the collimator 18 is made to enter between the two optical sheets (diffusion sheets).

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

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

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

In a typical TV device, the light emitted from the liquid crystal display panel 11 has similar diffusion characteristics in both the horizontal direction of the screen (shown on the X-axis in FIG. 12(a)) and the vertical direction of the screen (shown on the Y-axis in FIG. 12(b)). In contrast, the diffusion characteristics of the light flux emitted from the liquid crystal display panel of this embodiment are 1/5 of the 62 degrees of a typical TV device, when the viewing angle at which the luminance is 50% of that when viewed from the front (angle 0 degrees) is set to 13 degrees, as shown in example 1 of FIG. 12. Similarly, the vertical viewing angle is optimized by optimizing the reflection angle of the reflective light guide and the area of the reflection surface so that the upper viewing angle is approximately 1/3 of the lower viewing angle, with the upper and lower viewing angles being unequal. As a result, the amount of image light directed in the monitoring direction is significantly improved compared to conventional LCD TVs, and the luminance is more than 50 times higher.

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

As described above, by making the viewing angle a narrow angle, the amount of light flux heading in the monitoring direction can be concentrated, greatly improving the efficiency of light utilization. As a result, even if a liquid crystal display panel for general TV applications is used, by controlling the light diffusion characteristics of the light source device, it is possible to achieve a significant improvement in brightness with similar power consumption, making it possible to create an image display device that is compatible with information display systems facing bright outdoors.

When using a large LCD display panel, the overall brightness of the screen can be improved by directing the light around the periphery of the screen inwards so that it faces the observer when he or she is facing the centre of the screen. Figure 11 shows the convergence angle of the long and short sides of the panel when the observer's distance from the panel L and the panel size (screen ratio 16:10) are used as parameters. When monitoring with the screen vertically long, the convergence angle can be set to match the short side; for example, when using a 22-inch panel vertically and the monitoring distance is 0.8 m, a convergence angle of 10 degrees will allow the image light from the four corners of the screen to be effectively directed towards the observer.

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

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

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

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

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

The floating-in-space image display device 1000A according to the second embodiment is installed vertically so that the surface on which the floating-in-space image 3 is formed is the front of the floating-in-space image display device 1000A (facing the user 230), similar to the example shown in FIG. 4C. In other words, the floating-in-space image display device 1000A is installed vertically so that the transparent member 100 faces the user 230.

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

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

The internal structure of the spatially floating image display device 1000A will be described in more detail below. The spatially floating image display device 1000A has three spatial image display devices (also called spatial image display units) 1300 that form the spatially floating images 3. Each spatial image display device 1300 forms one spatially floating image 3. In this example, each spatial image display device 1300 displays still images of the "A" button, the "B" button, and the "C" button as the spatially floating image 3. Note that the spatial image display device 1300 may be configured to form multiple spatially floating images 3.

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

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

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

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

The mask display unit 1310 transmits the light emitted by the light source device 1330 through the mask member 1320, and outputs it as image light of any shape. As shown in FIG. 16, the mask member 1320 has a transmissive portion 1321 of a predetermined shape through which the light incident from the light source device 1330 passes, and a low-transmissive portion 1322 that has a lower light transmittance than the transmissive portion 1321. In the example shown in FIG. 16, the circular white portion is the transmissive portion 1321. The alphabet "A" portion is the low-transmissive portion 1322, which has a lower transmittance than the transmissive portion 1321 but transmits light. The black portion around the transmissive portion 1321 is the non-transmissive portion 1323, and almost no light incident from the light source device 1330 passes through.

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

This mask member 1320 is formed by reducing the transmittance of a portion of a base substrate made of a transparent material. For example, the mask member 1320 is formed by reducing the transmittance of the base substrate except for the area that will become the transmissive portion 1321. There are no particular limitations on the material of the base substrate as long as it is a transparent material, but for example, glass, plastic, etc. are preferably used.

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

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

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

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, as shown in FIG. 18.

The light source 1331 generates light to form the floating image 3, which is a still image, and may be, for example, a lamp, a single-color LED light source, a multi-color LED light source, a laser light source, or any other light source that emits visible light.

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

Optical element 1333 is for reducing the diffusion angle of the light emitted by light source 1331, and is composed of, for example, a collimator lens. In other words, optical element 1333 converts the light emitted by light source 1331 into approximately parallel light.

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

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

The image light emitted from the light source device 1330 configured in this way and transmitted through the mask member 1320 is incident on the retroreflector 5 diagonally downward, is reflected by the retroreflector 5 and travels diagonally upward. Then, a floating image 3, which is a still image of the push button, is formed on the outside of the transparent member 100.

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

As shown in FIG. 19, the image light control sheet 335 has a sandwich structure in which transparent sections 336 made of transparent silicon and light-shielding sections 337 made of black silicon of a specified thickness are arranged alternately at a specified interval, and a synthetic resin layer (not shown) is arranged on the light entrance and exit surfaces where light enters and exits.

The image light control sheet 335 is oriented 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 seen by the user 230. In other words, the multiple light-shielding portions 337 constituting the image light control sheet 335 are arranged in a so-called louver shape. Note that, for example, a viewing angle control film (VCF) can be used as the image light control sheet 335.

Here, it is preferable that the light-shielding portion 337 of the image light control sheet 335 is inclined with respect to the vertical direction (z direction). More specifically, it is preferable that the light-shielding portion 337 is inclined so as to be aligned with the traveling direction (optical axis) of the main ray L1 of the light (image light) that has passed through the mask member 1320, that is, the light that forms the floating image 3 in space. In this embodiment, as described above, the main ray L1 of the image light that has passed through the mask member 1320 is incident on the mask member 1320 at a predetermined angle θ1 with respect to the vertical direction (z direction). For this reason, it is preferable that the light-shielding portion 337 is also inclined with respect to the vertical direction (z direction) at a predetermined angle θ1.

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

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

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

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

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

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

<<Block diagram of the internal configuration of the space floating image display device>>
Fig. 20 is a block diagram showing an example of the internal configuration of the space-floating image display device 1000A. Next, the internal configuration of the space-floating image display device 1000A according to the second embodiment, in particular the internal configuration of the space image display device 1300, will be described using the block diagram of Fig. 20. Note that in Fig. 20, the same components as those of the space-floating image display device 1000 according to the first embodiment shown in Fig. 3 are given the same reference numerals, and duplicated descriptions will be omitted. Also, in Fig. 20, the illustration of the optical element 1333 is omitted.

As shown in FIG. 20, the spatially floating image display device 1000A of the second embodiment has a spatial image display device 1300. Although one spatial image display device 1300 is shown in FIG. 20, as described above, the spatially floating image display device 1000A of the second embodiment has three spatial image display devices 1300.

The spatial image display device 1300 includes a retroreflector 1101 corresponding to the retroreflector 5, and a mask display unit 1310. The mask display unit 1310 includes a light source 1331 and a light guide 1332 constituting a light source device 1330, and a mask member 1320. The spatial image display device 1300 further includes a power source 1106, an external power input interface 1111, an operation input unit 1107, a non-volatile memory 1108, a memory 1109, a control unit 1110, an aerial operation detection sensor 1351, an aerial operation detection unit 1350, and the like. The display color of the above-mentioned floating in space image 3 is changed, for example, by the control unit 1110 based on the detection result of the aerial operation detection sensor 1351.

Furthermore, in addition to the spatial image display device 1300, the spatial floating image display device 1000A may also 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, etc., and the control unit 1110 can change the display color of the spatial floating image 3 based on signals input from the video signal input unit 1131 and the communication unit 1132.

The components of the spatial floating image display device 1000A are mainly arranged in the housing 1190. When the spatial floating image display device 1000A includes multiple spatial image display devices 1300, it includes multiple components of each of the spatial image display devices 1300. However, some components, such as the control unit 1110, non-volatile memory 1108, and operation input unit 1107, may be common to multiple spatial image display devices 1300.

As described above, the configuration of the space-floating image display device 1000A according to the second embodiment allows the floating image 3, which is a still image such as a push button, to be displayed with a relatively simple structure. As a result, the size of the space-floating image display device 1000A can be reduced, and costs can also be reduced.

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

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

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

In the example shown in FIG. 21, each aerial image display device 1300 is arranged in a row along the x direction, tilted at a specific angle φ with respect to the y direction. In other words, the multiple spatial floating images 3 are arranged in a row along the x direction, tilted at a specific angle φ with respect to the y direction. The aerial image display device 1300 is configured to be rotatable horizontally within the housing 1190. The specific angle φ at which the spatial floating images 3 are tilted can be appropriately adjusted by rotating the aerial image display device 1300.

As a result, even if the space-floating image display device 1000A is installed near the wall W1 and the user 230 must view the space-floating image 3 at an angle to the front surface 1190a of the housing 1190, the user 230 can easily view the space-floating image 3. In other words, even if the line of sight 230E of the user 230 is forced to intersect with the y direction, the user 230 can easily view the space-floating image 3.

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

In the above-described second embodiment, the spatial floating image display device 1000A is exemplified as a configuration in which multiple spatial image display devices 1300 are arranged side by side in the horizontal direction, but the arrangement direction of the spatial image display devices 1300 is not particularly limited. For example, as shown in FIG. 23, multiple spatial image display devices 1300 may be arranged side by side in a row along the vertical direction (z direction). Multiple spatial floating images 3 may be displayed along the vertical direction (z direction). Of course, multiple spatial floating images 3 may be arranged side by side in a diagonal direction. For example, multiple spatial image display devices 1300 may be arranged side by side in a diagonal direction intersecting the vertical direction (z direction).

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

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

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

For this reason, if the mirror 1360 is not provided, the image light (light ray) emitted from near the end of the mask member 1320 in the x direction does not enter the retroreflector 5, as shown by the dotted arrow in FIG. 24, but travels outside the retroreflector 5 in the D1 or D2 direction. Therefore, for example, if the user 230 tries to look at the vicinity of both ends of the floating image 3 in an oblique direction from near the center of the retroreflector 5 in the x direction, it may be difficult to view the floating image 3 in the space. In other words, if the user 230 tries to look at the vicinity of both ends of the floating image 3 from near the center of the retroreflector 5 in the x direction, and the line of sight 230E of the user 230 crosses the y direction as shown in FIG. 24, it may be difficult to view the floating image 3 in the space.

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

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

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

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

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

As in this example, when a wall W2 is present to the left of the space-floating image display device 1000A, it is difficult to imagine a situation in which the user 230 would see the vicinity of the right edge of the space-floating image 3 from the outside left of the space-floating image display device 1000A. For this reason, even by providing a mirror 1360 only on the outside left edge of the retroreflector 5, the visibility of the space-floating image 3 for the user 230 can be improved as described above.

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

The floating-in-space image display device 1000A shown in FIG. 27 is an example further including a contact detector that detects contact of the user's 230 fingers with the transparent member 100, which is a protective plate. Specifically, in the floating-in-space image display device 1000A, the transparent member 100 is configured to be movable a predetermined amount in the y direction. For example, when the user 230 presses the transparent member 100 with his or her finger, the transparent member 100 is configured to move a predetermined amount in the y direction.

A movement detector that detects the movement of the transparent member 100 is provided on the inside of the transparent member 100, that is, on the side of the retroreflective plate 5. As an example, a push switch 1370 serving as a movement detector is provided on the inside of the transparent member 100 at a position that comes into contact when the transparent member 100 is pushed and moved. When the transparent member 100 moves and the push switch 1370 is pushed by the transparent member 100, the movement of the transparent member 100 is detected.

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

In this configuration, when the user 230 touches the floating-in-space image 3, even if the touch operation is not detected by the mid-air operation detection sensor 1351, the transparent member 100 is pressed, so that the touch operation by the user 230 can be reliably detected.

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

As an example, the capacitance sensor 1380 is provided over the entire surface of the transparent member 100 facing the user 230. The capacitance sensor 1380 only needs to be able to detect the contact of the user's 230 fingers with the transparent member 100 when the user 230 touches the floating-in-space image 3, and there are no particular limitations on its location or formation area. The capacitance sensor 1380 may be provided, for example, only in the area of the transparent member 100 that corresponds to the floating-in-space image 3.

Furthermore, the floating-in-space image display device 1000A shown in FIG. 28 includes a vibration generator 1390 that generates vibrations when a capacitance sensor 1380, which is a contact detector, detects contact of the user's 230 fingers with the transparent member 100. In this example, the vibration generator 1390 is provided on the inside of the transparent member 100, that is, on the retroreflector 5 side. The vibration generator 1390 is provided in contact with the lower part of the transparent member 100.

When the touch of the fingers of the user 230 on 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 in space image 3 by the user 230 is detected by the aerial operation detection sensor 1351, and the touch of the fingers of the user 230 on 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 fingers of the user 230 via the transparent member 100.

This allows the user 230 to reliably recognize that a touch operation on the floating-in-space image 3 has been detected. Therefore, even if the user 230 is, for example, visually impaired, the user can reliably recognize that the floating-in-space image 3 has been touch-operated.

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

The technology according to this embodiment displays high-resolution, high-brightness image information in a state where it floats in space, allowing users to operate the device without feeling anxious about contact infection. If the technology according to this embodiment is used in a system used by an unspecified number of users, it will be possible to provide a contactless user interface that can be used without anxiety, reducing the risk of contact infection. This will contribute to the achievement of "Good health and well-being for all," one of the Sustainable Development Goals (SDGs) advocated by the United Nations.

In addition, the technology according to this embodiment reduces the divergence angle of the emitted image light and aligns it to a specific polarization, so that only the normal reflected light is efficiently reflected by the retroreflector, making it possible to obtain bright and clear floating images with high light utilization efficiency. The technology according to this embodiment can provide a highly usable non-contact user interface that can significantly reduce power consumption. This contributes to the achievement of "9. Build resilient infrastructure, promote inclusive and sustainable industrialization and innovation" and "11. Make cities and towns inclusive and sustainable" of the Sustainable Development Goals (SDGs) advocated by the United Nations.

Various embodiments have been described above in detail, however, the present invention is not limited to the above-mentioned embodiments and includes various modified examples. For example, the above-mentioned embodiments are detailed descriptions of the entire system in order to clearly explain the present invention, and are not necessarily limited to those having all of the configurations described. It is also possible to replace 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. It is also possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

1...display device, 2, 5...retroreflector (retroreflector), 3...spatial image (floating image in space), 105...window glass, 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...phase difference plate, 230...user, 335...image light control sheet, 1000, 1000A...floating image display device, 1110...control control unit, 1160...image control unit, 1180...imaging unit, 1102...image display unit, 1300...spatial image display device (spatial image display unit), 1310...mask display unit, 1320...mask member, 1321...transmissive portion, 1322...low-transmissive portion, 1323...non-transmissive portion, 1330...light source device, 1331...light source, 1332...light guide, 1333...optical element, 1350...air operation detection unit, 1351...air operation detection sensor

Claims (16)

A floating-in-the-air image display device,
A light source device;
a mask member disposed so that the light emitted from the light source device is incident in an oblique direction, the mask member having a transmission portion of a predetermined shape that transmits the incident light;
A retroreflective member that reflects light transmitted through the mask member and displays a real image floating in the air by the reflected light;
and an operation detector for detecting an operation of the floating-in-the-air image by a user.
A floating image display device. The airborne image display device according to claim 1,
an image light control sheet disposed between the mask member and the retroreflective member and transmitting light transmitted through the mask member;
A floating image display device. The airborne image display device according to claim 1,
The light source device includes:
A light source;
a light guide that guides the light emitted from the light source so that the light is incident on the mask member in an oblique direction.
A floating image display device. The airborne image display device according to claim 3,
The light source device includes:
The light guide further includes an optical element disposed between the light source and the light guide, the optical element reducing a diffusion angle of the light emitted from the light source.
A floating image display device. The airborne image display device according to claim 3,
The light source emits light diagonally downward,
The airborne image is displayed by light directed obliquely upward by the retroreflective member,
The light source is disposed above the light guide and facing the light guide.
A floating image display device. The airborne image display device according to claim 1,
A reflective member is provided on at least one outer end of the retroreflective member, the reflective member being arranged along the direction of a principal ray of light emitted from the light source device.
A floating image display device. The airborne image display device according to claim 6,
The reflective members are disposed on the outer sides of both ends of the retroreflective member,
A floating image display device. The airborne image display device according to claim 6,
The reflecting member is provided continuously from the mask member to the portion corresponding to the floating image.
A floating image display device. The airborne image display device according to claim 1,
A protective plate is disposed between the retroreflective member and the floating image and is made of a transparent material;
The floating image is displayed by the light transmitted through the protective plate.
A floating image display device. The airborne image display device according to claim 9,
Further comprising a contact detector for detecting contact of the user's finger with the protective plate.
A floating image display device. The airborne image display device according to claim 10,
The contact detector includes:
Detecting contact of the protective plate with the contact detector;
When the protective plate is in contact with the contact detector, it is determined that the protective plate is in contact with a finger of the user.
A floating image display device. The airborne image display device according to claim 10,
The contact detector is a capacitance sensor provided on the protective plate.
A floating image display device. The airborne image display device according to claim 11,
a vibration generator attached to the protective plate and configured to generate vibrations when the contact detector detects contact of the user's finger with the protective plate;
A floating image display device. The airborne image display device according to claim 1,
A plurality of mask display units including the light source device and the mask member are provided.
A floating image display device. The airborne image display device according to claim 1,
The light source device includes:
A configuration capable of emitting light of multiple colors,
When the operation detector detects an operation of the floating-in-the-air image by the user, the color of the emitted light is changed.
A floating image display device. The airborne image display device according to claim 1,
the floating image being a still image of a push button;
A floating image display device.

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