JP2025037731A - Floating-air image display device - Google Patents

Abstract

To provide a technique that can display an air floating image more suitably, and contributes to "3 Good Health and Well-Being", "9 Industry, Innovation and Infrastructure" and "11 Sustainable Cities and Communities" of the Sustainable Development Goals.SOLUTION: An air floating image display apparatus includes: a display panel which displays an image; a polarization separation member which reflects a portion of image light emitted from the display panel; and a retroreflective member which is disposed so as to be opposite to the display panel, and retroreflects the reflected light from the polarization separation member. The reflected light retroreflected by the retroreflective member forms an air floating image via the polarization separation member. By forming the polarization separation member in a non-planar shape, the air floating image is formed in a non-planar shape.SELECTED DRAWING: Figure 15A

Description

This disclosure relates to technology for a floating image display device.

As an example of a space-floating image display device, an image display device and a display method that directly displays an image as a spatial image toward the outside are already known. In addition, a detection system that reduces false detections of operations on the operation surface of the displayed spatial image is also described, for example, in JP 2019-128722 A (Patent Document 1).

JP 2019-128722 A

However, the floating-in-space image display device of Patent Document 1 does not fully consider technology for displaying floating-in-space images more optimally under various usage conditions.

The objective of the present invention is to provide technology that can more effectively display floating images.

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 to give one example, a floating image display device that displays a floating image includes a display panel that displays an image, a polarization separation member that reflects a portion of the image light emitted from the display panel, and a retroreflective member that is arranged opposite the display panel and retroreflects the reflected light from the polarization separation member, and the reflected light reflected by the retroreflective member forms a floating image via the polarization separation member, and the polarization separation member is made to have a non-planar shape to form the floating image in a non-planar shape.

According to a representative embodiment of the present invention, a more suitable floating image display device can be realized. The above and other problems, as well as the configurations and effects for solving these problems, will be made clear through the explanation of the embodiment below.

1 is a diagram showing an example of a usage form of a space floating image display device according to an embodiment; FIG. 1 is a diagram showing a V-shaped configuration as an example of a main part configuration of a space floating image display device according to an embodiment. FIG. 1 is a diagram showing a Z-shaped configuration as an example of a main part configuration of a space floating image display device according to an embodiment. 4A to 4C are diagrams illustrating an example of a detailed structure of a retroreflective member. 1 is a characteristic diagram showing the relationship between the surface roughness of a retroreflective member and the amount of blur of a retroreflected image (a spatially floating image). 1 is a diagram showing an example of the configuration of a video display device according to an embodiment; FIG. 1 is a diagram showing an example of a V-type configuration of a space floating image display device according to an embodiment (first embodiment). FIG. 13 is a diagram showing another example of a V-type configuration of the space floating image display device according to the embodiment (second embodiment). FIG. 13 is a diagram showing another example of a V-type configuration of the space floating image display device according to an embodiment (third embodiment). FIG. 13 is a block diagram showing an example of an internal configuration of a space floating image display device according to an embodiment (fourth embodiment). FIG. 13 is a diagram showing an example of a Z-type configuration of a space floating image display device according to an embodiment (fifth embodiment). FIG. 23 is a diagram showing another example of a Z-type configuration of the space floating image display device according to an embodiment (sixth embodiment). FIG. 13 is a diagram showing another example of a Z-type configuration of the space floating image display device according to an embodiment (seventh embodiment). 13A and 13B are diagrams showing examples of the shape of a polarization separation member in the space floating image display device according to an embodiment (eighth embodiment); FIG. 23 is a diagram showing another example of a Z-type configuration of the space floating image display device according to an embodiment (eighth embodiment). FIG. 23 is a diagram showing another example of a Z-type configuration of the space floating image display device according to an embodiment (eighth embodiment). FIG. 23 is a diagram showing another example of a Z-type configuration of the space floating image display device according to an embodiment (eighth embodiment). FIG. 23 is a diagram showing another example of a Z-type configuration of the space floating image display device according to an embodiment (eighth embodiment). FIG. 23 is a diagram showing another example of a Z-type configuration of the space floating image display device according to an embodiment (eighth embodiment). FIG. 23 is a diagram showing another example of a Z-type configuration of the space floating image display device according to an embodiment (eighth embodiment).

The following describes the embodiments of the present disclosure in detail with reference to the drawings. In the drawings, the same parts are generally given the same reference numerals, and repeated explanations are omitted. In the drawings, the representation of each component may not show the actual position, size, shape, range, etc., in order to facilitate understanding of the invention. For the purpose of explanation, when describing processing by a program, the program, functions, processing units, etc. may be described as the main body, but the main body of hardware for these is a processor, or a controller, device, computer, system, etc., configured with the processor, etc. The computer executes processing according to the program read into the memory by the processor, using resources such as memory and communication interfaces as appropriate. This realizes a specified function, processing unit, etc. The processor is configured with semiconductor devices such as a CPU/MPU or GPU, for example. The processor is configured with a device or circuit capable of performing a specified calculation. The processing is not limited to software program processing, and can also be implemented with a dedicated circuit. The dedicated circuit can be an FPGA, ASIC, CPLD, etc. The program may be installed as data in advance on the target computer, or may be distributed as data from a program source to the target computer and installed. The program source may be a program distribution server on a communication network, or a non-transient computer-readable storage medium, such as a memory card or a disk. The program may be composed of multiple modules. The computer system may be composed of multiple devices. The computer system may be composed of a client-server system, a cloud computing system, or the like. The various data and information are composed of structures such as tables and lists, for example, but are not limited to these. Expressions such as identification information, identifiers, IDs, names, and numbers are mutually interchangeable.

<Embodiment>
The space-floating image display device of the embodiment is configured to include an image display device, a beam splitter which is a polarization separation member, and a retroreflective member having a λ/4 plate (phase difference plate, quarter-wave plate) on the retroreflective surface. The image display device is configured to include a light source device, and a display panel or liquid crystal display panel which emits image light of a specific polarization (e.g., P-polarized light) as an image source (image display element). The light source device generates and supplies light as a backlight to the liquid crystal display panel. A polarization separation member is disposed in a space connecting the liquid crystal display panel of the image display device and the retroreflective member. The polarization separation member has a property of transmitting the image light of a specific polarization from the liquid crystal display panel toward the retroreflective member, and reflecting the image light of the other polarization (e.g., S-polarized light) after polarization conversion by the retroreflective member and the λ/4 plate. The image light of the other polarization after reflection generates and displays a space-floating image which is a real image at a predetermined position in a direction different from the image display device.

The image display device may be provided with a polarization conversion section that aligns the light source light from the light source device to a specific direction of polarization in order to improve the contrast performance of the spatial floating image. For example, the light source device includes a point or planar light source, an optical element section that reduces the divergence angle of the light from the light source, a polarization conversion section (such as a polarization conversion element) that aligns the light from the light source to a specific direction of polarization, and a light guide having a reflective surface that propagates the light from the light source to the liquid crystal display panel, and controls the image luminous flux of the image light from the liquid crystal display panel by the shape and surface roughness of the reflective surface of the light guide.

The floating-in-space image display device of the embodiment is configured with an image display device unit having a housing that can be placed on a desk, and a floating-in-space image display unit having a frame structure, taking into consideration use particularly indoors, although this is not limited thereto.

The image display unit mainly consists of a liquid crystal display panel and a light source (backlight).

The floating-in-space image display unit is configured with an optical system that includes a polarized light separation member and a retroreflective member. The optical system in this embodiment has a structure that is supported by a frame that includes grooves, metal, resin, etc.

[Space-floating image display device]
The following embodiment relates to a space-floating image display device that can display an image generated by image light from a large-area image emission source as a space-floating image inside or outside the store space by transmitting the image generated by image light from a large-area image emission source through a transparent member that divides the space, such as the glass of a show window. In addition to the above embodiment, the present invention relates to a space-floating image display device that is mainly used for displaying space-floating images indoors, using an optical system composed of a polarization separation member (in other words, a polarizing beam splitter, or simply a beam splitter) and a retroreflector, and the like, which is generated by image light from a smaller-area image emission source (for example, about 2 to 5 inches).

In the following description of the embodiments, the image floating in space is expressed by the term "floating image in space." Instead of this term, it is also possible to express it as "aerial image," "floating image in space," "floating optical image of a displayed image," "floating optical image of a displayed image," etc. The term "floating image in space" used in the description of the embodiments is used as a representative example of these terms.

According to the following embodiment, for example, it is possible to display high-resolution image information floating in space on the glass surface of a shop window or on a light-transmitting plate. Furthermore, the floating-in-space image display device of the embodiment can be installed in a relatively small space, such as on a desk in a study, on a table in a living room, or on a kitchen counter.

In the conventional floating image display device, an organic EL panel or liquid crystal display panel is used as a high-resolution color display image source in combination with a retroreflective material. In the conventional floating image display device, the image light is diffused over a wide angle, which causes the following problems:

As shown in Figure 4, in the retroreflective member 2, the retroreflective member 2a is a hexahedron, so in addition to the normally reflected light, ghost images are generated by the image light that is obliquely incident on the retroreflective member 2, which causes a problem of impairing the image quality of the floating image in space. The retroreflective member 2 is also called a retroreflective plate or a retroreflective sheet.

As shown in Figure 5, the floating image obtained by reflecting the image light from the image display device (image source) by the retroreflective member 2 has the problem that, in addition to the ghost image mentioned above, blurring occurs in each pixel of the liquid crystal display panel.

1 shows an example of the use form and configuration of a space-floating image display device according to an embodiment. (A) of FIG. 1 shows the overall configuration of the space-floating image display device according to this embodiment. For example, in a store or the like, a show window (window glass) 105, which is a light-transmitting member (also described as a transparent member) such as glass, divides the space. According to the space-floating information display device of this embodiment, it is possible to display the space-floating image 3 in one direction to the outside of the store space through such a transparent member 100. Specifically, light with a narrow-angle directional characteristic and a specific polarization is emitted as an image light beam from the image display device 1 in the space-floating information display device, once enters the retroreflective member 2, is retroreflected, and passes through the window glass 105 to form the space-floating image 3, which is a real image, outside the store space. (A) of FIG. 1 shows a case where the back side of the window glass 105 in the depth direction is the store space and the front side is the outside store space (for example, the sidewalk). On the other hand, by providing the window glass 105 with a means for reflecting a specific polarized wave (such as an optical component), the image light beam can be reflected to form a floating image 3 at a desired location within the store.

(B) of FIG. 1 shows a block diagram of the image display device 1 described above. The image display device 1 includes an image display unit 1a that displays the original image of the floating image 3, an image control unit 1b that converts the input image to match the resolution of the panel of the image display unit 1a, an image signal receiving unit 1c that receives an image signal, and a receiving antenna 1d. The image signal receiving unit 1c supports wired input signals such as USB (Universal Serial Bus: registered trademark) input and HDMI (High-Definition Multimedia Interface: registered trademark) input, and wireless input signals such as Wi-Fi (Wireless Fidelity: registered trademark). The image display device 1 functions independently as an image receiving and display device, and can also display image information from an external PC, tablet, smartphone, etc. Furthermore, the image display device 1 can be equipped with capabilities such as calculation processing and image analysis processing by connecting a stick PC, etc.

[V-type space floating image display device]
FIG. 2 shows an example of the configuration of the main part of a space floating image display device according to an embodiment. The embodiment of FIG. 2 shows a configuration in which an image display device 1 and a retroreflective member (in other words, a retroreflective plate) 2 are arranged in a substantially V-shape (hereinafter, referred to as a V-shape). As shown in FIG. 2, in the V-shape configuration, an image display device 1 that generates image light of a specific polarization is provided in an oblique direction (a direction corresponding to an optical axis A1) relative to a transparent member 100 such as a flat glass (arranged horizontally in this example). In addition, a retroreflective member 2 is provided in another oblique direction (a direction corresponding to an optical axis A2) relative to the transparent member 100 such as a flat glass. The image display device 1 is composed of a light source device 13, a liquid crystal display panel 11 which is a liquid crystal display element, an absorbing polarizing plate 12, and the like.

In FIG. 2, image light of a specific polarization emitted from the liquid crystal display panel 11 of the image display device 1 travels in the direction of optical axis A1, is reflected by a beam splitter 101 (polarization separation member) having a film that selectively reflects image light of a specific polarization provided on a transparent member 100, travels in the direction of optical axis A2, and enters the retroreflective member 2. In this example, the beam splitter 101 is formed in a sheet shape and adhered to the underside of the transparent member 100 such as flat glass. Alternatively, the beam splitter 101 may be formed by evaporating an optical thin film directly onto the flat glass.

A λ/4 plate 21 is provided on the image light incidence surface (in other words, the retroreflective surface) of the retroreflective member 2. In other words, the λ/4 plate 21 is a polarization conversion element, a phase difference plate, and a quarter-wave plate.

The image light on the optical axis A2 from the beam splitter 101 is polarized and converted from a specific polarization (one polarized wave) to the other polarized wave by passing through the λ/4 plate 21 twice, once when entering the retroreflective member 2 and once when exiting from the retroreflective member 2. Here, the beam splitter 101, which selectively reflects the image light of a specific polarization, has the property of transmitting the image light of the other polarized wave after the polarization conversion. Therefore, the image light of the other polarized wave after the polarization conversion passes through the beam splitter 101. The image light that passes through the beam splitter 101 forms and displays a real image, a floating image 3, at a predetermined position outside the transparent member 100 in the direction of the optical axis A3 corresponding to the optical axis A2.

The light that forms the floating image 3 is a collection of light rays that converge from the retroreflective member 2 to the optical image of the floating image 3, and these light rays continue to travel straight even after passing through the optical image of the floating image 3. Therefore, in the configuration of FIG. 2, when a user views the floating image 3 from direction A indicated by the arrow, which corresponds to the optical axis A3, the floating image 3 is seen as a bright image. However, when viewed by another person from direction B indicated by the arrow, for example, the floating image 3 cannot be seen as an image at all. Such characteristics are very suitable for use in systems that display images that require high security or highly confidential images that should be concealed from people directly facing the user.

Depending on the performance of the retroreflective member 2, the polarization axis of the reflected image light may become misaligned. In this case, some of the image light with the misaligned polarization axis is reflected by the beam splitter 101 described above and returns to the image display device 1. This returned light may be re-reflected on the image display surface of the liquid crystal display panel 11 constituting the image display device 1, generating a ghost image and possibly degrading the image quality of the floating image 3. Therefore, in this embodiment, an absorbing polarizing plate 12 is provided on the image display surface of the image display device 1. The image light emitted from the image display device 1 is transmitted through the absorbing polarizing plate 12, and the reflected light returning from the beam splitter 101 is absorbed by the absorbing polarizing plate 12. This makes it possible to suppress the re-reflection and prevent degradation of image quality due to ghost images of the floating image 3.

The beam splitter (polarization separation member) 101 described above is formed, for example, from a reflective polarizing plate or a metal multilayer film that reflects a specific polarized wave. More specifically, the beam splitter 101 can be formed by evaporating an optical thin film onto flat glass (for example, quartz glass).

[Z-type space floating image display device]
Fig. 3 shows an example of the configuration of the main parts of a space floating image display device according to an embodiment, which is different from the embodiment in Fig. 2. The embodiment in Fig. 3 shows a configuration in which an image display device 1 and a retroreflective member 2 (retroreflective plate) are arranged opposite each other, and a beam splitter 101 is arranged in the space connecting them at an angle of about 45 degrees to the image display device 1 and the retroreflective member 2, roughly in a Z shape (or an inverted Z shape) (hereinafter referred to as Z shape).

The Z-shaped configuration shown in FIG. 3 includes a transparent member 100 such as a glass plate and an absorbing polarizing plate 112 for the purpose of reducing the effect of external light incident from direction C on the retroreflective member 2 and image display device 1. As shown in FIG. 3, the image display device 1 and the retroreflective member 2 are arranged at an angle of about 90 degrees to the transparent member 100 and the absorbing polarizing plate 112, and at an angle of about 45 degrees to the beam splitter 101. In this embodiment, the beam splitter 101 is arranged horizontally, and the position of the image displayed on the image display device 1, more specifically the liquid crystal display panel 11, and the position where the floating image 3 is formed are in a plane-symmetrical relationship with the beam splitter 101.

[Retroreflective member]
4 shows an example of the surface shape of a retroreflector as a representative retroreflective member 2. A light ray incident on the interior of regularly arranged triangular pyramid prisms is reflected by three walls and a bottom surface of the triangular pyramid prism and is emitted as retroreflected light in a direction corresponding to the incident light, and a real image floating in space is displayed based on the image displayed on the display device 1.

The resolution of the floating image 3 depends largely on the outer diameter D and pitch P of the retroreflective area 2a (area surrounded by a hexagon) of the retroreflective member 2 shown in FIG. 4, 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 11, even if one pixel (one triplet) is about 80 μm, if the diameter D of the retroreflective area 2a is 240 μm and the pitch P is 300 μm, one pixel of the floating image 3 is equivalent to 300 μm. Therefore, the effective resolution of the floating image 3 is reduced to about 1/3. Therefore, in order to make the resolution of the floating image 3 equivalent to the resolution of the image display device 1, it is desirable to make the diameter D and pitch P of the retroreflective area 2a close to one pixel of the liquid crystal display panel 11. On the other hand, in order to suppress the occurrence of moire caused by the retroreflective member 2 and the pixels of the liquid crystal display panel 11, it is advisable to design the pitch ratio of each to be a different integer multiple of one pixel. Also, it is advisable to arrange the shape so that none of the sides of the retroreflective area 2a overlaps with any of the sides of one pixel of the liquid crystal display panel 11.

The surface shape of the retroreflector according to this embodiment is not limited to the above example. It may have various surface shapes that realize retroreflection. Specifically, a retroreflection element in which triangular pyramid prisms, hexagonal pyramid prisms, other polygonal prisms, or a combination of these are periodically arranged may be provided on the surface of the retroreflector of this embodiment. Alternatively, a retroreflection element in which these prisms are periodically arranged to form a cube corner may be provided on the surface of the retroreflector of this embodiment. These can also be expressed as a corner reflector array or a multifaceted reflector array. Alternatively, a capsule lens type retroreflection element in which glass beads are periodically arranged may be provided on the surface of the retroreflector 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, the techniques disclosed in JP 2001-33609 A, JP 2001-264525 A, JP 2005-181555 A, JP 2008-70898 A, JP 2009-229942 A, etc. may be used.

The inventors have experimentally determined the relationship between the amount of blur l (small L) and the pixel size L (large L) of the image of the floating image 3 that can be tolerated to improve visibility by creating an image display device 1 that combines a liquid crystal display panel 11 with a pixel pitch of 40 μm and a light source device 13 with a narrow divergence angle (divergence angle of 15°) of this embodiment. Figure 5 shows the experimental results. It was found that the amount of blur l that deteriorates visibility is preferably 40% or less of the pixel size, and is barely noticeable if it is 15% or less. It was found that the surface roughness of the reflective surface at which the amount of blur l is tolerable is an average roughness of 160 nm or less within a measurement distance of 40 μm, and that to make the amount of blur l less noticeable, the surface roughness of the reflective surface is preferably 120 nm or less. For this reason, it is desirable to reduce the surface roughness of the retroreflective member 2 described above, and to make the surface roughness of the reflective film and its protective film that form the reflective surface less than the above-mentioned value.

On the other hand, in order to manufacture the retroreflective member 2 at a low cost, it is advisable to use a roll press method for molding. Specifically, this method involves aligning the retroreflective members 2a and shaping them on a film. In this method, the inverse shape of the shape to be shaped is formed on the roll surface, an ultraviolet-curable resin is applied onto a base material for fixing, and the required shape is formed by passing it between the rolls, and then the resin is irradiated with ultraviolet light to harden it, resulting in the retroreflective member 2 of the desired shape.

The image display device 1 of this embodiment uses a liquid crystal display panel 11 and a light source device 13 (see FIG. 6 for details) as a light source that generates light of a specific polarization, which reduces the possibility of image light being incident obliquely on the retroreflective member 2 described above. As a result, the occurrence of ghost images is suppressed, and even if a ghost image does occur, the brightness of the ghost image is low, resulting in a structurally excellent system.

On the other hand, in the configuration of the Z-type floating image display device shown in FIG. 3, the image display device 1, which is configured with a liquid crystal display panel 11, an absorptive polarizer 12, and a light source device 13, is arranged at a predetermined angle (for example, an angle of about 45 degrees with respect to the beam splitter 101 in the horizontal plane). The image light from the image display device 1 passes through the beam splitter 101 in the direction of optical axis B1 (diagonal direction with respect to the beam splitter 101) and proceeds toward the retroreflective member 2 in the direction of optical axis B2 (corresponding to direction D) that corresponds to the optical axis B1.

Here, the image light from the image display device 1 is image light having the characteristics of, for example, P-polarized (parallel polarization) as light of a specific polarization. The beam splitter 101 is a polarization separation member such as a reflective polarizing plate, and has the property of transmitting P-polarized image light from the image display device 1 but reflecting S-polarized (vertical polarization) image light. This beam splitter 101 is formed from a reflective polarizing plate or a metal multilayer film that reflects specific polarization. This beam splitter 101 can generally be formed by evaporating an optical thin film on a flat glass substrate. Therefore, the refractive index of the beam splitter 101 has substantially the same value as the refractive index n (n ≒ 1.5) of flat glass.

On the other hand, a λ/4 plate 21 is provided on the light incidence surface (retroreflective surface) of the retroreflective member 2. The P-polarized image light transmitted through the beam splitter 101 from the image display device 1 is polarized and converted from P-polarized light to S-polarized light by passing through the λ/4 plate 21 twice in total when it enters and exits the retroreflective member 2. As a result, the S-polarized image light after polarization conversion from the retroreflective member 2 is reflected by the beam splitter 101 and travels toward the transparent member 100, etc. The S-polarized image light that travels in a direction corresponding to the optical axis B3 after reflection (diagonal direction with respect to the beam splitter 101) passes through the transparent member 100 made of a glass plate or the like and the absorbing polarizing plate 112, and generates and displays the real image 3 floating in space at a predetermined position outside the transparent member 100, etc.

To reduce image quality degradation caused by sunlight or illumination light entering an optical system composed of optical components such as the image display device 1, the retroreflective member 2, and the beam splitter 101, an absorptive polarizing plate 112 may be provided on the outer surface of the transparent member 100. Since the polarization axis may become misaligned due to light being retroreflective by the retroreflective member 2, some of the image light may be reflected by the beam splitter 101 and returned to the image display device 1. This returned light is reflected again by the image display surface of the liquid crystal display panel 11 constituting the image display device 1, generating a ghost image and significantly degrading the image quality of the floating image 3 in space.

Therefore, in both the embodiments shown in Figures 2 and 3, an absorptive polarizer 12 is provided on the image display surface of the image display device 1. Alternatively, an anti-reflection film (not shown) may be provided on the image output side of the absorptive polarizer 12 provided on the surface of the image display device 1. In this way, the light that causes ghost images to be generated is absorbed by the absorptive polarizer 12, thereby preventing degradation of image quality due to ghost images of the floating image 3 in space.

Furthermore, in the Z-shaped configuration of FIG. 3, when external light is directly incident on the retroreflective member 2, a strong ghost image is generated. Therefore, in order to suppress and prevent the generation of this ghost image, in this embodiment, the retroreflective member 2 is tilted downward with respect to the direction of incidence of the external light to prevent the incidence of the external light. Specifically, the main incident direction of the external light is set to a direction (diagonal direction like the optical axis B3) corresponding to the direction C indicated by the arrow (the direction in which the user views the floating image 3 from the front). In this case, the retroreflective member 2 is arranged so that the optical axis B2 is, for example, at about 90 degrees relative to the direction C (optical axis B3). In other words, the main surface of the retroreflective member 2 is arranged so that it is, for example, at about 90 degrees relative to the main surface of the transparent member 100, etc. As a result, when the external light is incident in the direction C, it does not directly enter the main surface (retroreflective surface) of the retroreflective member 2, thereby preventing the generation of a ghost image.

The image display device 1 is also arranged in a different direction from the incident direction of the external light (direction C). Specifically, the main surface (image light exit surface) of the image display device 1 is arranged in the same direction (in other words, parallel) as the main surface of the retroreflective member 2, and the optical axis B1 of the image display device 1 is arranged at an angle of about 90 degrees to the optical axis B3 corresponding to the incident direction of the external light (direction C). In addition, when considering the range of the light flux when external light is incident on the main surface of the transparent member 100 functioning as an opening in direction C, the image display device 1 is arranged at a position slightly outside that range. This reduces the occurrence of ghost images caused by re-reflection at the image display device 1.

[Image display device]
Fig. 6 shows a configuration example of an image display device 1 applicable to the embodiments of Fig. 2 and Fig. 3. This image display device 1 is configured to include a light source device 13, a liquid crystal display panel 11, a light direction conversion panel 54, etc. The image emission surface side of the liquid crystal display panel 11 may be provided with the above-mentioned absorptive polarizing plate 12. The light source device 13 is configured to include a plurality of LED elements 201 (LEDs: Light Emitting Diodes) which are semiconductor light sources (solid light sources) constituting the light source, a light guide 203, etc. Fig. 6 shows a developed perspective view of the liquid crystal display panel 11 and the light direction conversion panel 54 arranged on the light emission side of the light source device 13.

The light source device 13 is formed, for example, from a plastic case (not shown) and is configured to house the LED elements 201 and the light guide 203 inside. A light receiving end surface 203a is provided on the light incident side of the light guide 203 to convert the divergent light from each LED element 201 into a substantially parallel light beam. The light receiving end surface 203a has a shape in which the cross-sectional area gradually increases toward the opposite side to the light receiving portion, and is provided with a lens shape that has the effect of gradually decreasing the divergence angle by multiple total reflections as the light propagates inside.

Furthermore, the liquid crystal display panel 11 is attached to the upper surface of the light guide 203, and is disposed approximately parallel to the light guide 203. The upper surface of the light guide 203 serves as an emission surface that emits light reflected by the light guide 203. Furthermore, a plurality of LED elements 201 are attached to one side (the lower side in FIG. 6) of the case of the light source device 13. The light from the plurality of LED elements 201 is converted into approximately collimated light (approximately parallel light) by the shape of the light receiving end surface 203a of the light guide 203. For this reason, the light receiving portion of the light receiving end surface 203a and the LED elements 201 are attached while maintaining a predetermined positional relationship.

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 a light receiving section provided on the light incident side of the light guide 203. The divergent light beam from the LED elements 201 is made into approximately collimated light by the lens shape of the light receiving end surface 203a of the light guide 203. This approximately collimated light is guided inside the light guide 203 in the direction A indicated by the arrow. The direction A is approximately parallel to the liquid crystal display panel 11 (from bottom to top in the drawing). The light guided in the direction A has its light beam direction converted by the light beam direction conversion section 204 provided in the light guide 203, and is emitted in the direction B indicated by the arrow toward the liquid crystal display panel 11, which is approximately parallel to the light guide 203. The direction B is approximately perpendicular to the display surface of the liquid crystal display panel 11.

The light guide 203 has a configuration in which the distribution (in other words, density) of the light beam direction conversion section 204 is optimized depending on the shape inside or on the surface of the light guide 203. This makes it possible to control the uniformity of the light, which is the light beam emitted from the light source device 13 shown in direction B and incident on the liquid crystal display panel 11.

Furthermore, in the image display device 1 including the light source device 13 and the liquid crystal display panel 11, the directivity of the light from the light source device 13 in the direction B can be controlled to improve the utilization efficiency of the light flux emitted from the light source device 13 in the direction B and to significantly reduce power consumption. More specifically, a light source having a narrow divergence angle can be configured as the light source device 13. As a result, the image light from the image display device 1 can reach the observer efficiently with high directivity (in other words, linearity) like laser light, and a high-quality floating image can be displayed with high resolution. At the same time, the power consumption by the image display device 1 including the LED elements 201 of the light source device 13 can be significantly reduced.

The liquid crystal display panel 11 is attached to a frame (not shown) of the liquid crystal display panel 11, which is attached to the top surface of a case (not shown) of the light source device 13. The liquid crystal display panel 11 is attached to the frame, and a flexible printed circuit board (FPC: Flexible Printed Circuits) (not shown) electrically connected to the liquid crystal display panel 11 is attached to the frame. The liquid crystal display panel 11, which is a liquid crystal display element, generates a display image by modulating the intensity of transmitted light together with the LED elements 201 based on a control signal from a control circuit (not shown) that constitutes the electronic device.

Next, a tabletop type floating image display device according to one embodiment will be described with reference to FIG. 7 and subsequent figures. The basic configuration of the floating image display device according to each embodiment shown in FIG. 7 to FIG. 9 corresponds to the V-shaped configuration shown in FIG. 2.

[First embodiment]
FIG. 7 shows an example of the configuration of the main parts of a space floating image display device 400 suitable for installation on a desk, according to one embodiment (hereinafter referred to as a first embodiment).

Figure 7 shows a cross-sectional view of the space-floating image display device 400 as seen from the side. The front of the device here is the surface that corresponds to the direction in which the space-floating image 3 (3A, 3B) formed by the space-floating image display device 400 can be viewed from the front by the user (230A, 230B).

Directions AA and AB are the directions in which the user views the floating-in-space image 3 (3A, 3B) from the front, and correspond to the negative direction in the Y direction.

For the purpose of explanation, a coordinate system and directions such as (X, Y, Z) shown in the figure may be used. In this figure, the Z direction is the vertical direction, the up-down direction, the X direction and the Y direction are two horizontal directions that intersect at right angles, the X direction is the depth direction, the front-to-back direction (the front-to-back horizontal direction within the screen of the floating image 3), and the Y direction is the left-to-right direction (the left-to-right horizontal direction within the screen of the floating image 3).

The basic configuration of the V-shaped structure in FIG. 7 is the same as that of the V-shaped structure in FIG. 2 in terms of the positional relationship of the components (image display device 1, beam splitter 101A and transparent member 100A, and retroreflective member 2, etc.). In addition, the image display device 1 includes a liquid crystal display panel 11 and a light source device 13.

Note that, hereinafter, the beam splitter 101A and the transparent member 100A will be treated as one unit, and the transparent member will be abbreviated. Other similar components will also be abbreviated in the same way.

In order to form the floating-in-space image 3A, the components of the floating-in-space image display device 400 (image display device 1, beam splitter 101A, retroreflective member 2, etc.) are arranged with a predetermined positional relationship to each other. That is, the image display device 1, beam splitter 101A, retroreflective member 2, etc. in FIG. 7 are arranged with a predetermined positional relationship to form a V-shape, similar to the configuration in FIG. 2. The formed floating-in-space image 3A can be viewed from the front by the user 230A from the direction AA.

The floating image display device 400 of the first embodiment shown in FIG. 7 is provided with a hinge mechanism 330 that serves as a rotation fulcrum at one end of the beam splitter 101A. The hinge mechanism 330 is a mechanism that does not move up, down, left, or right, but is free to rotate. It is provided in the X direction at the left end of the beam splitter 101A, and the beam splitter 101A is structured to rotate up and down around the hinge mechanism 330 as a rotation fulcrum. In other words, the floating image display device shown in FIG. 7 is provided with a display panel that displays an image, a polarized light separation member that reflects a portion of the image light emitted from the display panel, and a retroreflective member that retroreflects the reflected light from the polarized light separation member, and the reflected light reflected by the retroreflective member passes through the polarized light separation member to form a floating image, and the angle of the polarized light separation member with respect to the display panel and the retroreflective member is variable.

In other words, the image display device 1 and the retroreflective member 2 are fixedly arranged, while the beam splitter 101A and the transparent member 100A can be arranged at different angles. Alternatively, the beam splitter 101A and the transparent member 100A can be rotated around the hinge mechanism 330 as a rotation fulcrum, and the distance between the beam splitter 101A and the image display device 1, and the beam splitter 101A and the retroreflective member 2 can be changed. Even if the arrangement angle of the beam splitter 101A and the transparent member 100A is different, they are arranged with a positional relationship so as to form a V shape, similar to the configuration in FIG. 2.

In the first embodiment of the floating-in-space image display device 400 shown in FIG. 7, the beam splitter 101A and the transparent member 100A are rotated upward by an angle γ with respect to the horizontal position (XY plane) using the hinge mechanism 330 as a rotation fulcrum, and placed at the position of the beam splitter 101B and the transparent member 100B. In this arrangement, the image light from the image display device 1 passes through the optical axis AB1, which is longer than the optical axis A1, is reflected by the beam splitter 101B, passes through the λ/4 plate 21 along the optical axis AB2, and enters the retroreflective member 2.

The image light that is retroreflected by the retroreflective member 2 and emitted passes through the λ/4 plate 21 again, where it is converted to the other polarized wave, and passes through the beam splitter 101B. The image light that passes through the beam splitter 101B forms and displays a real image, a floating-in-space image 3B, at a predetermined position outside the transparent member 100B in the direction of the optical axis AB3 corresponding to the optical axis AB2. The formed floating-in-space image 3B can be viewed as a bright image by the user 230B in a frontal position from the direction AB indicated by the arrow corresponding to the optical axis AB3.

Because beam splitter 101B is positioned above beam splitter 101A by angle γ, the length of optical axis AB1 from image display device 1 to beam splitter 101B is longer than optical axis A1 from image display device 1 to beam splitter 101A, and floating image 3B is formed at a higher position than floating image 3A. For this reason, when the height of the viewpoint position differs due to differences in height between users, it is possible to form floating image 3 at a position that is easy to see by changing the tilt angle of beam splitter 101.

In the embodiment of FIG. 7, the beam splitter 101A in the horizontal position forms a floating image 3A that is optimal for the user 230A, whereas the beam splitter 101B with an upward angle of γ with respect to the horizontal position (XY plane) forms a floating image 3B that is suitable for the user 230B who is taller than the user 230A.

[Second embodiment]
FIG. 8 shows a configuration example of a space floating image display device 400 suitable for installation on a desk, according to one embodiment (hereinafter referred to as a second embodiment).

Figure 8 shows a cross-sectional view of the space floating image display device 400 as seen from the side.

In this embodiment, the floating-in-space image display device 400 of the first embodiment in FIG. 7 is placed in a housing 4001, and the housing 4001 has an opening (opening hole) 4002 in the horizontal direction (parallel to the XY plane). The hinge mechanism 330 is provided at one end of the opening 4002, and rotatably holds the beam splitter 101A on one side of the beam splitter 101A opposite the user 230, and serves as a rotation fulcrum for the beam splitter 101A.

The floating-in-space image display device 400 also includes a control unit 500 having control functions, an imaging unit 510, and a piston mechanism 310 that moves the piston up and down or expands and contracts.

In FIG. 8, the positional relationship of the components (image display device 1, beam splitter 101A and transparent member 100A, retroreflective member 2, etc.) is the same as that of the V-shaped configuration in FIG. 7. Note that, hereinafter, beam splitter 101A and transparent member 100A may be treated as one unit, and the transparent member may be abbreviated. Other similar components may also be abbreviated in the same way.

In order to form the floating-in-space image 3A, the components of the floating-in-space image display device 400 (image display device 1, beam splitter 101A, retroreflective member 2, etc.) are arranged with a predetermined positional relationship to each other. That is, the image display device 1, beam splitter 101A, retroreflective member 2, etc. in FIG. 8 are arranged with a predetermined positional relationship to form a V-shape, similar to the configuration in FIG. 7. The formed floating-in-space image 3A can be viewed from the front by the user 230A from the direction AA.

This is an example of a structure in which the beam splitter 101A rotates or moves up and down around the hinge mechanism 330. In other words, the image display device 1 and the retroreflective member 2 are fixed in position, while the beam splitter 101A and the transparent member 100A can be positioned at different angles. Alternatively, the beam splitter 101A and the transparent member 100A can be rotated around the hinge mechanism 330, changing the separation distance between the beam splitter 101A and the image display device 1, and the separation distance between the beam splitter 101A and the retroreflective member 2. In other words, the floating image display device shown in FIG. 8 includes a display panel that displays an image, a polarization separation member that reflects a portion of the image light emitted from the display panel, and a retroreflective member that retroreflects the light reflected from the polarization separation member, and the light reflected by the retroreflective member passes through the polarization separation member to form a floating image, and the angle of the polarization separation member relative to the display panel and the retroreflective member is variable.

The piston mechanism 310 is disposed on the side of the beam splitter 101A and the transparent member 100A that faces the hinge mechanism 330. In the initial state, the piston of the piston mechanism 310 is in contact with one side of the beam splitter 101A and the transparent member 100A at the length of the piston 310A, and holds the beam splitter 101A and the transparent member 100A horizontally (parallel to the XY plane). When the piston 310A of the piston mechanism 310 extends and is in the state of piston 310B, the beam splitter 101A and the transparent member 100A rotate upward by an angle γ with respect to the horizontal position (XY plane) with the hinge mechanism 330 as the rotation fulcrum, and move to the position of the beam splitter 101B and the transparent member 100B. That is, the piston mechanism 310 rotates the beam splitter 101A around the hinge mechanism 330 of the rotation axis, allowing the angle relative to the image display device 1 and the retroreflective member 2 to be changed.

At the position of the beam splitter 101B and the transparent member 100B, the image light from the image display device 1 passes through the optical axis AB1, which is longer than the optical axis A1, is reflected by the beam splitter 101B, passes through the λ/4 plate 21 along the optical axis AB2, and enters the retroreflective member 2. The image light that is retroreflectively reflected by the retroreflective member 2 passes through the λ/4 plate 21 again, is converted to the other polarized wave, and transmits the beam splitter 101B. The image light that has transmitted through the beam splitter 101B forms and displays a real image, a floating image 3B, at a predetermined position outside the transparent member 100B, in the direction of the optical axis AB3 corresponding to the optical axis AB2. The formed floating image 3B can be viewed as a bright image by the user 230B in the direction AB indicated by the arrow corresponding to the optical axis AB3 when positioned in front of the user 230B.

The arrangement of the piston mechanism 310 is not limited to this embodiment, and similar effects can be obtained by arranging it on other sides of the beam splitter 101A and the transparent member 100A, or in multiple positions. Also, the method of rotating or driving the beam splitter 101A in the vertical direction with the hinge mechanism 330 as the rotation fulcrum is not limited to the piston mechanism 310.

(Regarding the imaging unit, control unit, etc.)
The imaging unit 510 captures images of the height, face, and facial components such as the eyes and mouth of the user 230, and information such as the height and face of the user 230 is input to the control unit 500. The imaging unit 510 detects, for example, the position of the eyes of the user 230 from the input information of the user 230, and obtains information on the height of the eyes of the user 230.

If the obtained eye height information of the user 230 differs from the pre-assumed viewing height, the control unit etc. 500 can drive the piston mechanism 310 to change the angle of the beam splitter 101A to a position optimal for viewing by the user 230.

For example, if user 230A is at a predetermined viewing height, image capture unit 510 and control unit 500 control piston mechanism 310 so that beam splitter 101A holds the horizontal position. In the case of user 230B who is taller than user 230A, image capture unit 510 and control unit 500 extend piston 310A of piston mechanism 310 to piston 310B, and change the position of beam splitter 101A to that of beam splitter 101B tilted by angle γ, so that user 230B can view a bright image from a frontal position.

[Third Example]
FIG. 9 shows a configuration example of a space floating image display device suitable for installation on a desk, according to one embodiment (hereinafter referred to as a third embodiment).

Figure 9 shows a cross-sectional view of the space floating image display device as seen from the side. In this embodiment, the space floating image display device 400 is placed inside the housing 4001.

In FIG. 9, the positional relationship of the components (image display device 1, beam splitter 101A and transparent member 100A, retroreflective member 2, etc.) is the same as that of the V-shaped configuration in FIG. 2. Note that, hereinafter, beam splitter 101A and transparent member 100A may be treated as one unit, and the transparent member may be abbreviated. Other similar components may also be abbreviated in the same way.

In order to form the floating-in-space image 3A, the components of the floating-in-space image display device (image display device 1, beam splitter 101A, retroreflective member 2, etc.) are arranged with a predetermined positional relationship to each other. That is, the image display device 1, beam splitter 101A, retroreflective member 2, etc. in FIG. 9 are arranged with a predetermined positional relationship to form a V-shape, similar to the configuration in FIG. 2. The formed floating-in-space image 3A can be viewed from the front by user 230A in direction AA.

In the third embodiment of the floating-in-space image display device shown in Fig. 9, the hinge mechanism 331 is provided near the center of the opening 4002, and rotatably holds both ends of the beam splitter 101A at or near the center line of the beam splitter 101A that is parallel to one side of the beam splitter 101A facing the user 230, and serves as a rotation fulcrum for the beam splitter 101A. The hinge mechanism 331 does not move up, down, left, or right, but is free to rotate, and the beam splitter 101A rotates up and down around the hinge mechanism 331 as a rotation fulcrum. In other words, the floating image display device shown in FIG. 9 includes a display panel that displays an image, a polarization separation member that reflects a portion of the image light emitted from the display panel, and a retroreflective member that retroreflects the light reflected from the polarization separation member, and the light reflected by the retroreflective member passes through the polarization separation member to form a floating image, and the angle of the polarization separation member relative to the display panel and the retroreflective member is variable.

In other words, the image display device 1 and the retroreflective member 2 are fixedly arranged, while the beam splitter 101A and the transparent member 100A can be arranged at different angles. Alternatively, the beam splitter 101A and the transparent member 100A can be rotated around the hinge mechanism 331 as a rotation fulcrum, and the distance between the beam splitter 101A and the image display device 1, and the beam splitter 101A and the retroreflective member 2 can be changed. Even if the arrangement angle of the beam splitter 101A and the transparent member 100A is different, they are arranged with a positional relationship so as to form a V shape, similar to the configuration in FIG. 2.

The piston mechanism 310 is disposed on the side of the beam splitter 101A and the transparent member 100A facing the user 230. In the initial state, the piston of the piston mechanism 310 is in contact with one side of the beam splitter 101A and the transparent member 100A at the length of the piston 310A, and holds the beam splitter 101A and the transparent member 100A horizontally (parallel to the XY plane). When the piston 310A of the piston mechanism 310 extends and is in the state of piston 310C, the beam splitter 101A and the transparent member 100A rotate upward by an angle γ with respect to the horizontal position (XY plane) with the hinge mechanism 331 as the rotation fulcrum, and move to the position of the beam splitter 101C and the transparent member 100C. That is, the piston mechanism 310 rotates the beam splitter 101A with the hinge mechanism 331 of the rotation axis as the rotation fulcrum, and the angle with respect to the image display device 1 and the retroreflective member 2 can be changed.

In this configuration, the image light from the center position of the image display device 1 is reflected or passes along the optical axes A1, A2, and A3 on the rotation fulcrum axis (X-axis direction) of the hinge mechanism 331 of the beam splitter 101A. Even when the beam splitter 101A and the transparent member 100A rotate by an angle and the image light from the center position of the image display device 1 reaches the position of the beam splitter 101C and the transparent member 100C, the path and length of the optical path are almost unchanged, so the image light is reflected by the beam splitters 101A and 101C, passes through the λ/4 plate 21 along the optical axis A2, and enters the retroreflective member 2.

The image light that is retroreflected by the retroreflective member 2 passes through the λ/4 plate 21 again and is converted to the other polarized wave, and then passes through the beam splitters 101A and 101C. The image light that passes through the beam splitters 101A and 101C generates a real image, a floating image, at a predetermined position outside the transparent members 100A and 100C in the direction of the optical axis A3 that corresponds to the optical axis A2, and the floating images are generated at approximately the same position, so that the floating images 3A and 3C almost overlap.

In this configuration, consider image light from a position away from the center of the image display device 1. When image light with optical axis A11 at the bottom end (left end in FIG. 9) of the image display device 1 is reflected by the beam splitter 101A, it passes through the λ/4 plate 21 along the optical axis A12 and enters the retroreflective member 2. The image light that is retroreflected by the retroreflective member 2 passes through the λ/4 plate 21 again and is converted to the other polarized wave, and passes through the beam splitter 101A. The image light that passes through the beam splitter 101A generates a real image, a floating image 3A, at a predetermined position outside the transparent member 100A in the direction of the optical axis A13 corresponding to the optical axis A12.

Next, when the beam splitter 101A and the transparent member 100A rotate by an angle γ and reach the position of the beam splitter 101C and the transparent member 100C, the image light of the optical axis A11 at the lower end of the image display device 1 is reflected by the beam splitter 101C, passes through the λ/4 plate 21 along the optical axis C12, and enters the retroreflective member 2. The image light retroreflected by the retroreflective member 2 passes through the λ/4 plate 21 again, is converted to the other polarized wave, and transmits through the beam splitter 101C. The image light transmitted through the beam splitter 101C generates a real image, a floating image 3C, at a predetermined position outside the transparent member 100C in the direction of the optical axis C13 corresponding to the optical axis C12.

The distance between the bottom end of the image display device 1 and the beam splitter 101C becomes shorter than the distance between the image display device 1 and the beam splitter 101A due to the rotation of the angle γ, in other words, the optical path distance becomes shorter, so that the position of the top end (left end in FIG. 9) of the generated floating-in-space image 3C becomes lower than the position of the top end of the floating-in-space image 3A. When the image light of the optical axis A21 of the top end (right end in FIG. 9) of the image display device 1 is reflected by the beam splitter 101A, it passes through the λ/4 plate 21 along the optical axis A22 and enters the retroreflective member 2. The image light that is retroreflected by the retroreflective member 2 and emitted passes through the λ/4 plate 21 again, is converted into the other polarized wave, and transmits through the beam splitter 101A. The image light transmitted through the beam splitter 101A generates a real image, a floating image 3A, at a predetermined position outside the transparent member 100A in the direction of optical axis A23, which corresponds to optical axis A22.

Next, when the beam splitter 101A and the transparent member 100A rotate by an angle γ and come to the position of the beam splitter 101C and the transparent member 100C, the image light of the optical axis A21 at the upper end of the image display device 1 is reflected by the beam splitter 101C, passes through the λ/4 plate 21 along the optical axis C22, and enters the retroreflective member 2. The image light retroreflected by the retroreflective member 2 passes through the λ/4 plate 21 again, is converted to the other polarized wave, and transmits through the beam splitter 101C. The image light transmitted through the beam splitter 101C generates a real image, a floating image 3C, at a predetermined position outside the transparent member 100C in the direction of the optical axis C23 corresponding to the optical axis C22.

The distance between the top of the image display device 1 and the beam splitter 101C becomes longer than the distance between the image display device 1 and the beam splitter 101A due to the rotation of the angle γ, in other words, the optical path distance becomes longer, so that the bottom end (left end in FIG. 9) of the generated floating-in-space image 3C becomes higher than the top end of the floating-in-space image 3A.

In other words, the floating image in space 3C is tilted counterclockwise more than the floating image in space 3A, or the tilt angle of the floating image in space 3C occurs at a shallower angle closer to the horizontal plane than the floating image in space 3A. The floating image in space 3C can be seen as a bright floating image in front of the user 230C, who is taller or has a higher viewpoint than the user 230A, in the direction AC indicated by the arrow.

[Fourth embodiment]
Next, a block diagram of the internal configuration of the space floating image display device 400 will be described.

Figure 10 is a block diagram showing an example of the internal configuration of the space floating image display device 400. The space floating image display device 400 includes a retroreflective member 2, a liquid crystal display panel 11, a light guide 203, a light source device 13, 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, a video signal input unit 1131, an audio signal input unit 1133, a communication unit 1132, an aerial operation detection sensor 1351, an aerial operation detection unit 1350, an audio output unit 1140, a video control unit 1160, a storage unit 1170, an imaging unit 510, a beam splitter 101, a beam splitter angle adjustment unit 1010, and the like.

Here, the beam splitter angle adjustment unit 1010 includes the piston mechanism 310 shown in Figures 8 and 9, and adjusts the angle of the beam splitter 101 relative to the image display device 1 and the retroreflective member 2.

In addition, a removable media interface 1134, a position sensor 1113, a transmissive self-luminous image display device (not shown), a second display device (not shown), or a secondary battery 1112 may also be provided.

The components of the space floating image display device 400 are arranged in a housing 4001. Note that the imaging unit 510 and the aerial operation detection sensor 1351 may be provided on the outside of the housing 4001.

The retroreflective member 2 retroreflects the light modulated by the liquid crystal display panel 11. The light reflected from the retroreflective member 2 is output to the outside of the spatial floating image display device 400 to form the spatial floating image 3.

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

The light source device 13 supplies light to the liquid crystal display panel 11 and is a solid-state light source such as an LED light source or a laser light source. The power supply 1106 converts AC current input from the outside via the external power supply input interface 1111 into DC current and supplies power to the light source device 13. The power supply 1106 also supplies the necessary DC current to each part within the space floating image display device 400.

The secondary battery 1112 stores the power supplied from the power source 1106. Furthermore, when power is not supplied from the outside via the external power input interface 1111, the secondary battery 1112 supplies power to the light source device 13 and other components that require power. In other words, when the space floating image display device 400 is equipped with the secondary battery 1112, the user can use the space floating image display device 400 even when power is not supplied from the outside.

The light guide 203 guides the light generated by the light source device 13 and irradiates it onto the liquid crystal display panel 11. The combination of the light guide 203 and the light source device 13 can also be called the backlight of the liquid crystal display panel 11. The light guide 203 may be configured mainly using glass. The light guide 203 may be configured mainly using plastic. The light guide 203 may be configured using a mirror. There are various possible methods for combining the light guide 203 with the light source device 13.

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. The mid-air operation detection sensor 1351 senses, for example, the entire display range of the floating-in-space image 3 and the range that overlaps with it.

The aerial operation detection sensor 1351 may sense only a range that overlaps with at least a portion of the display range of the floating image 3. Specific examples of the aerial operation detection sensor 1351 include distance sensors that use invisible light such as infrared rays, invisible light lasers, 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., made by the user with his/her finger 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 the finger of the user 230 has touched an object in the floating-in-space image 3 and calculating the position (contact position) where 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 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 400, or may be provided separately from the space-floating image display device 400. When provided separately from the space-floating image display device 400, 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 400 via a wired or wireless communication connection path or image signal transmission path.

Also, 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 main body is the floating-in-space image display device 400, which does not have an aerial operation detection function, and only the aerial operation detection function can be added as an option.

Also, the aerial operation detection sensor 1351 alone may be a separate component, and the aerial operation detection unit 1350 may be built into the space-floating image display device 400. In cases where it is desired to more freely position the aerial operation detection sensor 1351 relative to the installation position of the space-floating image display device 400, there is an advantage to a configuration where only the aerial operation detection sensor 1351 alone is a separate component.

The imaging unit 510 is a camera with an image sensor, and captures the face, eyes, arms, fingers, and/or the space near the floating image 3 of the user 230.

For example, the information on the face and eyes of the user 230 captured by the imaging unit 510 is used to detect the position of the face and eyes of the user 230 by the beam splitter angle adjustment unit 1010, and height information is obtained. If the obtained height information differs from the pre-determined viewing height, the beam splitter angle adjustment unit 1010 can drive the piston mechanism 310 to change the angle of the beam splitter 101 to a position optimal for viewing by the user 230.

A plurality of imaging units 510 may be provided. By using a plurality of imaging units 510, or by using an imaging unit with a depth sensor, the aerial operation detection unit 1350 can be assisted in the detection process of the touch operation of the user 230 on the floating-in-space image 3. The imaging unit 510 may be provided separately from the floating-in-space image display device 400. When the imaging unit 510 is provided separately from the floating-in-space image display device 400, it is sufficient to configure it so that an imaging signal can be transmitted to the floating-in-space image display device 400 via a wired or wireless communication connection path or the like.

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 images captured by the multiple imaging units 510 and object depth information from a depth sensor. This information and various information such as the distance between the object and the intrusion detection plane are then used for various display controls for the floating-in-space image 3. Also, without using the mid-air operation detection sensor 1351, the mid-air operation detection unit 1350 may detect a touch operation on the floating-in-space image 3 by the user 230 based on the images captured by the imaging units 510.

The imaging unit 510 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. In addition, the imaging unit 510 may capture an image of 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 230'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 space floating image 3, the operation input unit 1107 may be used, for example, by an administrator to operate the space floating image display device 400.

The video signal input unit 1131 connects to an external video output device and inputs video data. The video signal input unit 1131 can be implemented using a variety of digital video input interfaces. For example, it can be implemented using 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 can be provided.

The audio signal input unit 1133 is connected to an external audio output device and inputs audio data. The audio signal input unit 1133 may be configured with 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 the terminals and cables are integrated.

The audio output unit 1140 can output 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 and error warning sounds. Alternatively, the audio output unit 1140 may be configured to output a digital signal to an external device, such as the Audio Return Channel function defined in the HDMI standard.

The non-volatile memory 1108 stores various data used by the space floating image display device 400. The data stored in the non-volatile memory 1108 includes, for example, data for various operations to be displayed on the space floating image 3, display icons, data for objects to be operated by the user, layout information, etc. The 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 400.

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 data such as video data, image data, and audio data are sent and received by communication via the communication unit 1132.

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 such as 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 liquid crystal display panel 11 and the retroreflective member 2.

The storage unit 1170 is a storage device that records various information such as various data such as video data, image data, and audio data. The storage unit 1170 may be configured with a magnetic recording medium recording device such as a hard disk drive (HDD) or a semiconductor element memory such as a solid state drive (SSD). For example, various information such as various data such as video data, image data, and audio data may be recorded in advance in the storage unit 1170 at the time of product shipment. In addition, the storage unit 1170 may record various information such as various data such as video data, image data, and audio data obtained 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 floating-in-space image 3 via the liquid crystal display panel 11 and the retroreflective member 2. The video data, image data, etc. of the display icons and objects for the user to operate, which are displayed as the floating-in-space image 3, are also recorded in the storage unit 1170.

Layout information of display icons and objects displayed as the floating-in-space image 3, various metadata information related to the objects, and the like 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 image control unit 1160 performs various controls related to the image signal input to the liquid crystal display panel 11. The image control unit 1160 may be called an image processing circuit, and may be configured with hardware such as an ASIC, an FPGA, or an image processor. The image control unit 1160 may also be called an image processing unit or an image processing unit. The image control unit 1160 performs image switching control, such as which image signal is input to the liquid crystal display panel 11 out of the image signal stored in the memory 1109 and the image signal (image data) input to the image signal input unit 1131. The image control unit 1160 may also generate a superimposed image signal by superimposing the image signal 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 liquid crystal display panel 11 to form a composite image as a floating 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 for enlarging, reducing, transforming, etc. an image, brightness adjustment processing for changing the brightness, contrast adjustment processing for changing the contrast curve of an image, and Retinex processing for decomposing an image into light components and changing the weighting of each component. The video control unit 1160 may also perform special effect video processing, etc. for assisting the aerial operation (touch operation) of the user 230 on the video signal input to the liquid crystal display panel 11. 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 and the captured image of the user 230 by the imaging unit 510.

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 400 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, when an undesirable attitude is detected as the user's usage state, the control unit 1110 may perform control to stop displaying the image displayed on the liquid crystal display panel 11 and display an error message to the user. Alternatively, when the attitude sensor 1113 detects that the installation attitude of the space floating image display device 400 has changed, the control unit 1110 may perform control to rotate the display direction of the image displayed on the liquid crystal display panel 11.

As explained above, the space-floating image display device 400 is equipped with various functions. However, the space-floating image display device 400 does not need to have all of these functions, and can have any configuration as long as it has the function of forming the space-floating image 3.

[Fifth Example]
The space floating image display devices of the embodiments shown in FIGS. 11 to 13 correspond, as a basic configuration, to the Z-type configuration shown in FIG.

Figure 11 shows an example of the configuration of a floating-in-space image display device suitable for installation on a desk, according to one embodiment (hereinafter referred to as the fifth embodiment).

Figure 11 shows a cross-sectional view (A) of the floating-in-space image display device as viewed from the side, and a top view (B) of the device as viewed from the front. The front of the device here is the surface corresponding to the direction in which the user can view the floating-in-space image 3D formed by the floating-in-space image display device 400 from the front. Direction D is the direction in which the user views the floating-in-space image 3D from the front, and corresponds to the negative direction in the Z direction. For the sake of explanation, a coordinate system or direction such as the illustrated (X, Y, Z) may be used. The Z direction is the vertical direction, the up-down direction, the X direction and the Y direction are two horizontal directions that are orthogonal to each other, the X direction is the depth direction, the front-back direction (the horizontal front-back direction within the screen of the floating-in-space image 3D), and the Y direction is the left-right direction (the horizontal left-right direction within the screen of the floating-in-space image 3D).

The Z-shaped configuration in FIG. 11 has the same positional relationship of the components (image display device 1, beam splitter 101D, retroreflective member 2A, etc.) as the Z-shaped configuration in FIG. 3. In order to form the floating-in-space image 3D, the components of the floating-in-space image display device (image display device 1, beam splitter 101D, retroreflective member 2, etc.) are arranged with a predetermined positional relationship. That is, the image display device 1, beam splitter 101D, retroreflective member 2A, etc. of the image display device unit 300 in FIG. 11 are arranged with a predetermined positional relationship so as to form a Z shape, similar to the configuration in FIG. 3.

The fifth embodiment of the floating image display device shown in FIG. 11 is roughly divided into an image display device unit 300, a housing 106 corresponding to the image display device unit 300, a floating image display device 400, a housing 4001 having an opening 4002 corresponding to the floating image display device 400, and a hinge mechanism 332 that serves as a rotation fulcrum at one end of the beam splitter 101D.

The hinge mechanism 332 is provided on the housing 4001, and rotatably holds the beam splitter 101D at one side of the beam splitter 101D opposite the user 230, and serves as a rotation fulcrum for the beam splitter 101D.

The image display device 1 is mounted and stored in a storage section of the housing 106. In FIG. 11, if the X-Y plane shown in the figure is the desk surface (the horizontal plane in this example), the housing 106 is placed along the X-Z plane perpendicular to the desk surface.

The housing 106 is roughly rectangular and flat with a given height (a given thickness in the Y direction). Inside the housing 106, the image display device 1 is placed along the X-Z plane on the desk surface. The floating-in-space image display device 400 is placed opposite the housing 106 in the Y direction.

The space-floating image display device 400 is mounted and housed in a housing 4001. The space-floating image display device 400 is composed of a retroreflective member 2A, a λ/4 plate 21A, a beam splitter 101D, and the like.

In this embodiment, a transparent member 100 such as a glass plate and an absorbing polarizing plate 112 are provided to reduce the effect of external light entering through the opening 4002 on the retroreflective member 2A and the image display device 1. In this embodiment, the direction D is from top to bottom in the Z direction, which is the vertical direction, and is perpendicular to the opening 4002.

In this embodiment, the beam splitter 101D is disposed at an angle to the desk surface inside the housing 4001. "At an angle" refers to the angle that the direction of one side of the main surface of the beam splitter 101D makes with the Y direction of the desk surface (X-Y plane). For example, in FIG. 11, the angle α, which is the angle of the angle, is about 45 degrees (≒45°).

The retroreflective member 2A and the λ/4 plate 21A are arranged on the opposite side of the beam splitter 101D in the Y direction from the image display device 1 (FIG. 11). The λ/4 plate 21A is arranged on the side of the main surface of the retroreflective member 2A where the beam splitter 101D is arranged. In other words, the λ/4 plate 21A is arranged on the light incident side of the retroreflective member 2A. The floating image 3D (shown in a dashed frame) is arranged in the horizontal direction (X-Y plane) between the housing 106 and the retroreflective member 2A, emerging from the beam splitter 101D in the Z direction upward. The floating image 3D is an aerial image formed in response to the beam splitter 101D.

In this embodiment, the components of the image display device 1, i.e., the light source device 13, the liquid crystal display panel 11, and the absorptive polarizer 12, etc., are housed and fixed in the housing 106.

An opening 1061 is provided on the left side surface in the Y direction of the housing 106 and on the right side surface in the Y direction of the housing 4001. The opening 1061 is a portion through which the image light from the image display device 1 passes or is transmitted. A transparent member or the like may be provided in the opening 1061. The image light corresponding to the image displayed on the image display device 1, more specifically the liquid crystal display panel 11, passes through this opening 1061 and travels toward the beam splitter 101D located to the left (negative direction) in the Y direction.

As with the configuration described above (Figure 3), the beam splitter 101D has the property of transmitting P-polarized light and reflecting S-polarized light, and can be formed, for example, by evaporating an optical thin film onto a flat glass substrate. In this case, the angle of incidence of the polarized light on the beam splitter 101D is approximately 45 degrees ±15 degrees, and a 3D floating-in-space image is generated that is positioned in the horizontal direction (X-Y plane).

In FIG. 11, the image light emitted from the image display device 1 through the opening 1061 in the negative direction in the Y direction on the optical axis D1 is shown by a dashed arrow. This is shown as a representative example of four dashed arrows for the beam splitter 101D. The image light emitted from the liquid crystal display panel 11 is light having a predetermined polarization characteristic, for example, P polarization (parallel polarization: P is an abbreviation for Parallel). This P-polarized image light passes through the beam splitter 101D on the optical axis D1 in the negative direction (left) in the Y direction as it is, and proceeds toward the retroreflective member 2A on the optical axis D2 corresponding to the optical axis D1. The beam splitter 101D has the property of passing P-polarized light and reflecting S-polarized light (vertical polarization: S is an abbreviation for Senkrecht). The beam splitter 101D is arranged so as to form an angle of, for example, about 45 degrees with this P-polarized image light (optical axis D2, Y direction). In other words, the beam splitter 101D is positioned so that its principal surface forms an angle of approximately 45 degrees with respect to the Z direction that forms the principal surfaces of the liquid crystal display panel 11 and the retroreflective member 2A.

A λ/4 plate 21A is provided on the light incidence surface of the retroreflective member 2A. The P-polarized image light with optical axis D1 emitted from the image display device 1 and transmitted through the beam splitter 101D passes through the λ/4 plate 21A twice, once before and once after being reflected by the retroreflective member 2A, and is polarized and converted from P-polarized to S-polarized light. As a result, the S-polarized image light traveling on the optical axis D2 after being reflected by the retroreflective member 2 is reflected by the beam splitter 101D and travels on the optical axis D3 in the Z direction. As shown in the figure, this S-polarized image light generates and displays a real image, a floating image 3D, at a predetermined position in the Z direction after passing through the outside of the opening 4002, the transparent member 100, and the absorbing polarizing plate 112.

The predetermined position where the floating image 3D is formed is determined according to the optical distance of the optical path of the optical system including the image display device 1, the beam splitter 101D, and the retroreflective member 2A. The distance between the floating image 3D and the beam splitter 101D is approximately equal to the distance between the image display device 1 and the beam splitter 101D.

The hinge mechanism 332 shown in FIG. 11 is a mechanism that does not move up, down, left, or right, but is free to rotate. It is provided in the X direction at the left end of the beam splitter 101D, and the beam splitter 101D rotates up and down around the hinge mechanism 332 as a rotation fulcrum. In other words, the image display device 1 and the retroreflective member 2 are fixed in position, while the beam splitter 101D can be positioned at a different angle. Alternatively, the beam splitter 101D can be rotated around the hinge mechanism 330 as a rotation fulcrum, changing the separation distance between the beam splitter 101D and the image display device 1, and between the beam splitter 101D and the retroreflective member 2A. Even if the angle of the beam splitter 101D is different, it is positioned with a positional relationship to form a Z-shape, similar to the configuration in FIG. 3.

In the fifth embodiment of the floating-in-space image display device shown in FIG. 11, consider the case where the beam splitter 101D is rotated upward by an angle γ with respect to the horizontal position (XY plane) with the hinge mechanism 332 as a rotation fulcrum, and moved to the position of the beam splitter 101E. In this arrangement, the P-polarized image light from the image display device 1 travels along the optical axis D1, passes through the beam splitter 101E, and passes through the λ/4 plate 21A twice in total, before and after being reflected by the retroreflective member 2A, thereby being polarized and converted from P-polarized light to S-polarized light. As a result, the S-polarized image light that traveled along the optical axis D2 after being reflected by the retroreflective member 2 is reflected by the beam splitter 101E and travels along the optical axis E3 in the Z direction. As shown in the figure, this S-polarized image light generates and displays a floating-in-space image 3E, which is a real image, at a predetermined position in the Z direction after passing through the outside of the opening 4002, the transparent member 100, and the absorbing polarizing plate 112.

The predetermined position where the floating image 3E is formed is determined according to the optical distance of the optical path of the optical system including the image display device 1, the beam splitter 101E, and the retroreflective member 2A. The distance between the floating image 3E and the beam splitter 101E is approximately equal to the distance between the image display device 1 and the beam splitter 101E.

By rotating the beam splitter 101E upward by an angle γ with respect to the horizontal position (XY plane) around the hinge mechanism 332, the distance between the image display device 1 and the beam splitter 101E becomes farther on the surface of the beam splitter 101E that is farther from the hinge mechanism 332 than on the surface of the beam splitter 101D. Therefore, the floating-in-space image 3E of the beam splitter 101E is generated and displayed at a position rotated upward by an angle γ with respect to the floating-in-space image 3D of the beam splitter 101D, which is in a nearly horizontal position. The formed floating-in-space image 3E can be viewed as a bright image by the user 230E in a frontal position from the direction E indicated by the arrow. In other words, by changing the tilt angle γ of the beam splitter 101D with the hinge mechanism 332 as the rotation fulcrum, the floating-in-space image 3D can be generated and displayed at a position tilted from the horizontal position.

The imaging unit 510 is a camera with an image sensor, and captures the faces, eyes, arms, fingers, and/or the space of the floating in space image 3D and the floating in space image 3E of the users 230D and 230E. For example, the beam splitter angle adjustment unit 1010 (FIG. 10) detects the positions of the faces and eyes of the users 230D and 230E from the information of the faces and eyes of the users 230D and 230E captured by the imaging unit 510, and drives the hinge mechanism 332 to adjust the angle of the beam splitter 101D from the angle optimal for the visibility of the user 230D to the angle optimal for the visibility of the beam splitter 101E of the user 230E.

[Sixth Example]
FIG. 12 shows an example of the configuration of a space floating image display device suitable for installation on a desk, according to one embodiment (hereinafter referred to as a sixth embodiment).

The embodiment of FIG. 12 is an arrangement in which the space floating image display device of the embodiment of FIG. 11 is rotated 90° to the left around the X axis. In this embodiment, the coordinate system has a Y direction that is the vertical direction, the up-down direction, a Z direction and a Y direction that are two horizontal directions that are orthogonal to each other, a X direction that is the depth direction, the front-back direction, and a Z direction that is the left-right direction. In other words, the coordinate relationship seen from the space floating image display device is the same in the embodiment of FIG. 11 and the embodiment of FIG. 12. The front of the device here is the plane (Y-X plane) that corresponds to the direction in which the user can view the space floating image 3D formed by the space floating image display device 400 from the front. Direction D is the direction in which the user views the space floating image 3D from the front, and corresponds to the negative direction in the Z direction.

The components of the space-floating image display device 400 in the embodiment of FIG. 12 are the same as those in the embodiment of FIG. 11, and the same reference numerals are used. The generation and display of the space-floating image 3D and the space-floating image 3E are performed by the same means. The viewpoint positions of the user 230D and the user 230E in the embodiment of FIG. 12 are in the same positional relationship as in the embodiment of FIG. 11, but the illustration assumes that the user 230D is taller than the user 230E. The space-floating image 3D facing forward is optimal for the user 230D. Because the user 230E is shorter than the user 230D, he or she will look up slightly at the space-floating image display device 400, and the space-floating image 3E will be facing forward, making it the optimal viewing position.

The imaging unit 510 is a camera with an image sensor, and captures the height, face, and eyes of the users 230D and 230E, and/or the floating-in-space image 3D and the space near the floating-in-space image 3E. For example, for user 230D, the beam splitter angle adjustment unit 1010 (FIG. 10) detects the eye position of user 230D from the height and face and eye position information of user 230D captured by the imaging unit 510, and adjusts the angle of the beam splitter 101 to the position of beam splitter 101D using the hinge mechanism 332. This allows user 230D to view the floating-in-space image 3D in the optimal position in the forward direction.

For short user 230E, the beam splitter angle adjustment unit 1010 (Fig. 10) detects the eye position of user 230E from the height of user 230E captured by imaging unit 510 and the position information of the face and eyes, and adjusts and places the angle of beam splitter 101D at the position of beam splitter 101E by rotating the angle of beam splitter 101D clockwise by rotation angle γ using hinge mechanism 332. This allows user 230E to view floating image 3E in the optimal position, looking slightly up and directly ahead.

This embodiment is not limited to cases where the user is shorter than user 230D, but is also effective for users taller than user 230D. By adjusting the angle of beam splitter 101D in a clockwise rotation based on, for example, eye position information of a user taller than user 230D captured by imaging unit 510, the tilt angle of the generated floating-in-space image can be adjusted to optimize visibility for users taller than user 230D. This improves visibility for the user (observer), and is ideal for improving operability.

[Seventh Example]
FIG. 13 shows a configuration example of a space floating image display device suitable for installation on a desk, according to one embodiment (hereinafter referred to as a seventh embodiment).

Figure 13 (A) shows a cross-sectional view of the appearance of a space-floating image display device according to one embodiment (seventh embodiment) when viewed from the side, and Figure 13 (B) shows a cross-sectional view of the appearance of a space-floating image display device according to one embodiment (seventh embodiment) when viewed from above. In Figure 13 (B), the retroreflective member 2B is arranged to face the liquid crystal display panel 11 at a predetermined angle. The front of the device here corresponds to the direction in which the user can view the space-floating image 3F formed by the space-floating image display device 400 from the front. Direction F is the direction in which the user 230F views the space-floating image 3F from the front, and corresponds to the negative direction in the Z direction.

The Z-shaped configuration in FIG. 13 has the same relative positions of the components (image display device 1, beam splitter 101F, retroreflective member 2B, etc.) as the Z-shaped configuration in FIG. 3.

In order to form the floating-in-space image 3F, the components of the floating-in-space image display device (image display device 1, beam splitter 101F, retroreflective member 2B, etc.) are arranged with a predetermined positional relationship. That is, the image display device 1, beam splitter 101F, retroreflective member 2B, etc. of the image display device unit 300 in FIG. 13 are arranged with a predetermined positional relationship so as to form a Z-shape, similar to the configuration in FIG. 3.

The seventh embodiment of the floating image display device shown in FIG. 13 is roughly divided into an image display device unit 300, a housing 106 corresponding to the image display device unit 300, a floating image display device 400, a housing 4001 having an opening 4002 corresponding to the floating image display device 400, and a hinge mechanism 333 that rotatably holds the beam splitter 101F.

The hinge mechanism 333 rotatably holds both ends of the beam splitter 101F at or near the center line of the beam splitter 101F, which is parallel to one side of the beam splitter 101F facing the user 230, and serves as a rotation fulcrum for the beam splitter 101F. The hinge mechanism 333 does not move up, down, left, or right, but is free to rotate, and the beam splitter 101F rotates up and down around the hinge mechanism 333. In other words, the beam splitter 101F can be positioned at a different angle relative to the fixed position of the image display device 1 and the retroreflective member 2B. Alternatively, the beam splitter 101F can be rotated around the hinge mechanism 333, changing the separation distance between the beam splitter 101F and the image display device 1, and between the beam splitter 101F and the retroreflective member 2B. Even if the angle at which the beam splitter 101F is positioned is different, it is positioned in a positional relationship to form a Z-shape, similar to the configuration in Figure 3.

The P-polarized image light emitted from the image display device 1 passes through the beam splitter 101F and reaches the λ/4 plate 21B. After passing through the λ/4 plate 21B, the image light is reflected by the retroreflective member 2B and passes through the λ/4 plate 21B a total of two times, resulting in the polarization conversion from P-polarized to S-polarized light. The image light is reflected by the beam splitter 101F and generates a floating image 3F in the Z-axis direction, i.e., the vertical direction.

In this embodiment, the unwanted light 600 is shown diagrammatically by a white arrow in FIG. 13(B). Of the P-polarized image light that becomes the unwanted light 600, a portion of the P-polarized image light that reaches the λ/4 plate 21B is specularly reflected by the surface of the λ/4 plate 21B and proceeds to the beam splitter 101F as P-polarized light. Furthermore, a portion of the P-polarized image light is also specularly reflected by the surface of the beam splitter 101F.

In this embodiment, the retroreflective member 2B and the λ/4 plate 21B are arranged at an angle on the X-Y plane, not parallel to the X-Z plane. Therefore, the P-polarized image light, which becomes the unnecessary light 600, is mirror-reflected on the surface of the λ/4 plate 21B in a direction parallel to the incident light on the Y-Z plane, but since the λ/4 plate 21B has an angle with respect to the X-Y plane, it is mirror-reflected at an angle corresponding to the incident angle and is incident on the surface of the beam splitter 101F at an angle on the X-Y plane. Therefore, the unnecessary light 600 is mirror-reflected on the surface of the beam splitter 101F at an angle corresponding to the incident angle, but it deviates from the Z direction, which is directly above, and travels in a direction outside the screen of the floating image 3F. As a result, when a user looks at the floating image 3F from the direction F, the unnecessary light 600 is outside the screen of the floating image 3F and is not visible, so that it is possible to avoid the unnecessary light 600 interfering with the visibility of the floating image in space.

In the first embodiment of the floating-in-space image display device shown in FIG. 13, the beam splitter 101F is rotated counterclockwise or upward by an angle γ with respect to the horizontal position (XY plane) around the hinge mechanism 333 provided at or near the center line of the beam splitter 101F as the rotation fulcrum, and is positioned at the position of the beam splitter 101J.

In this configuration, consider image light from a position away from the center of the image display device 1. When image light with optical axis F1 at the lower end of the image display device 1 is transmitted by the beam splitter 101F, it passes through the λ/4 plate 21B along the optical axis F1 and enters the retroreflective member 2B. The image light that is retroreflected by the retroreflective member 2 and emitted passes through the λ/4 plate 21B again and is converted to the other polarized wave, and the image light reflected by the beam splitter 101F generates a real image, a floating image 3F, at a specified position outside the transparent member 100 in the direction of optical axis F3 corresponding to optical axis F2.

Next, when the beam splitter 101F rotates by angle γ and reaches the position of the beam splitter 101J, the image light of the optical axis F1 of the image display device 1 passes through the beam splitter 101J, passes through the λ/4 plate 21B along the optical axis F2, and enters the retroreflective member 2B. The image light that is retroreflected by the retroreflective member 2B passes through the λ/4 plate 21B again and is converted to the other polarized wave, and is reflected by the beam splitter 101J, generating a real image, a floating image 3J, at a predetermined position outside the transparent member 100 in the direction of the optical axis J3.

The distance between the bottom end of the image display device 1 and the beam splitter 101J is shorter than that of the beam splitter 101F due to the rotation of the angle γ. In other words, the optical path distance is shorter, so the left end position of the generated floating-in-space image 3J is lower than the left end position of the floating-in-space image 3F.

Conversely, due to the rotation of angle γ, the distance between the top of image display device 1 and beam splitter 101J becomes farther than that of beam splitter 101F, in other words the optical path distance becomes longer, so the right end position of the generated floating-in-space image 3J becomes higher than the right end position of floating-in-space image 3F. In other words, floating-in-space image 3J is tilted counterclockwise more than floating-in-space image 3F. In other words, by changing the tilt angle γ of beam splitter 101F with hinge mechanism 333 as the rotation fulcrum, floating-in-space image 3F can be generated and displayed at a position tilted from the horizontal position.

The imaging unit 510 is a camera with an image sensor, and captures the faces, eyes, arms, and fingers of the users 230F and 230J, and/or the space of the floating image 3F and the floating image 3J. For example, the information on the faces and eyes of the users 230F and 230J captured by the imaging unit 510 can be used by the beam splitter angle adjustment unit 1010 (FIG. 10) to detect the positions of the faces and eyes of the users 230F and 230J, and drive the hinge mechanism 333 to adjust the angle of the beam splitter 101F, for example, from the optimal viewing position for the user 230F to an angle of the beam splitter 101J suitable for the viewing of the user 230J.

As described above, the floating image display device shown in Figures 7 to 9 includes a display panel that displays an image, a polarizing separator that reflects a portion of the image light emitted from the display panel, and a retroreflective member that retroreflects the light reflected from the polarizing separator. The light reflected by the retroreflective member passes through the polarizing separator to form a floating image, and the angle of the polarizing separator relative to the display panel and the retroreflective member is variable.

As described above, the floating image display device shown in Figures 11 to 13 also includes a display panel that displays an image, a polarization separation member that transmits a portion of the image light emitted from the display panel, and a retroreflective member that retroreflects the light that has transmitted through the polarization separation member, and the light that is retroreflected by the retroreflective member is reflected by the polarization separation member to form a floating image, and the angle of the polarization separation member relative to the display panel and the retroreflective member is variable.

As described above, the space-floating image display device of each embodiment and modification is suitable for use mainly indoors, and can display space-floating images with high visibility. Furthermore, the space-floating image display device of this embodiment is configured to display the spatial images at different heights and inclinations, improving visibility and operability. More specifically, a function is provided to adjust the angle of the beam splitter relative to the bottom surface, etc., and space-floating images with different heights and inclinations are displayed from each beam splitter.

This has the effect of improving the visibility and operability of the floating-in-space image for users with different viewing positions and heights. When the generated floating-in-space image is used as a non-contact user interface, it provides better usability for users, higher visibility and operability, and prevents or reduces operational errors and input errors.

This embodiment may be installed on a desk, for example. The λ/4 plate 21B may be positioned anywhere between the beam splitter 101 and the opening 4002, as long as it is located before the image of the floating image is formed. The retroreflective member 2 may be positioned so that it faces the liquid crystal display panel 11 at a predetermined angle.

As a result of the above effects, the floating-in-space image display device of each embodiment and modification can display bright, highly visible floating-in-space images without emitting unnecessary image light to people other than the user, even when used in a relatively small room, and is small and lightweight, making it ideal for easy installation on a desk, table, shelf, etc. indoors.

Although the embodiments of the present disclosure have been specifically described above, the present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the gist of the present disclosure. Unless otherwise specified, each component may be singular or plural. The components of each embodiment may be added, deleted, or replaced, with the exception of essential components. Also, combinations of each embodiment are possible.

For example, the beam splitter may be curved rather than flat. In the above embodiment, the user mainly views the floating image in the vertical direction, but the present invention is of course not limited to this. If the arrangement of the floating image display device in each embodiment is rotated overall, it is possible to display the floating image in a direction different from the above-mentioned example. The image display device 1 may also be called a display panel, liquid crystal display panel, liquid crystal panel, etc.

[Eighth Example]
The space floating image display devices of the embodiments shown in FIG. 14 and FIG. 15A to FIG. 15F correspond to the Z-type configuration shown in FIG. 3 as a basic configuration.

Figure 14 is a perspective view showing an example shape of a beam splitter (polarization separation member) that transmits a portion of the image light emitted from a display panel of a floating-in-the-air image display device suitable for installation on a desk, according to one embodiment (hereinafter referred to as the eighth embodiment). (A) is a flat beam splitter, and corresponds to 101D, 101J, etc. of the floating-in-the-air image display device shown in Figures 11 to 13. In contrast, (B), (C), and (D) show examples of beam splitter shapes that are curved rather than flat, with the height of the inside of the beam splitter differing from the surrounding edges of the beam splitter. Beam splitter 101K in (B) is a semi-cylindrical plate material surrounded by a pair of straight edges A1, A1' and a pair of curved edges B1, B1'. Beam splitter 101L in (C) is a semi-cylindrical plate material rotated 90 degrees from beam splitter 101K in (B), and is surrounded by a pair of straight sides A2, A2' and a pair of curved sides B2, B2'. Note that curved sides B1, B1', B2, B2' of beam splitters 101K and 101L are not limited to parts of a circle or ellipse, and may be approximate curves of curves or polygons with any curvature. Beam splitter 101P in (D) is a cone-shaped or lens-shaped plate material, with bottom peripheral portion B3 surrounded by a circle or curve, and the side faces rise obliquely toward the apex of the plate material. Bottom peripheral portion B3 is not limited to parts of a circle or ellipse, and may be approximate curves of curves or polygons with any curvature.

Figure 15A shows an example of the configuration of a space-floating image display device suitable for installation on a desk, according to one embodiment (referred to as the eighth embodiment). Figure 15A shows a Y-Z cross-sectional view (A) of the space-floating image display device when viewed from the side, an X-Y top view (B) and an X-Z cross-sectional view (C) when viewed from the front of the device. The front of the device here corresponds to the direction in which the user can view the space-floating image 3K formed by the space-floating image display device 400 from the front. Direction K is the direction in which the user 230K views the space-floating image 3K from the front, and corresponds to the negative direction in the Z direction. For the sake of explanation, a coordinate system or direction such as the illustrated (X, Y, Z) may be used. The Z direction is the vertical direction, the up-down direction, the X direction and the Y direction are two horizontal directions that intersect at right angles, the X direction is the depth direction, the front-to-back direction (the front-to-back horizontal direction on the screen of the floating-in-space image K), and the Y direction is the left-to-right direction (the left-to-right horizontal direction on the screen of the floating-in-space image 3K).

The Z-shaped configuration of FIG. 15A has the same positional relationship of the components (image display device 1, beam splitter 101K, retroreflective member 2A, etc.) as the Z-shaped configuration of FIG. 3. In order to form the function of the floating-in-space image 3K, the components of the floating-in-space image display device 400 (image display device 1, beam splitter 101K, retroreflective member 2A, etc.) are mutually arranged with a predetermined positional relationship. That is, the image display device 1, beam splitter 101K, retroreflective member 2A, etc. of the image display device unit 300 of FIG. 15A are arranged with a predetermined positional relationship so as to form a Z shape, similar to the configuration of FIG. 3.

The space-floating image display device 400 is mounted and stored in a housing 4001. The space-floating image display device 400 is composed of a retroreflective member 2A, a λ/4 plate 21A, a beam splitter 101K, etc.

In this embodiment, a transparent member 100 such as a glass plate and an absorbing polarizing plate 112 are provided to reduce the effect of external light entering through the opening 4002 on the retroreflective member 2A and the image display device 1. The direction K is the Z direction, which is the vertical direction in this embodiment, from top to bottom, and is perpendicular to the opening 4002.

In this embodiment, the beam splitter 101K is a semi-cylindrical plate material as shown in FIG. 14B, and is surrounded by a pair of straight sides and a pair of curved sides. Inside the housing 4001, the beam splitter 101K is disposed at an angle to the desk surface. The angle means that one straight side (e.g., A1) of the beam splitter 101K is disposed near the image display device 1, and the other straight side (e.g., A1') of the beam splitter 101K is disposed near the retroreflective member 2A. The angle formed by the direction of the line segment connecting both ends of the arc of the curved side surface of the beam splitter 101K corresponds to the Y direction of the desk surface (X-Y plane), and for example, in FIG. 15A, the angle α, which is the angle of the angle, is about 45 degrees (≒45°).

The retroreflective member 2A and the λ/4 plate 21A are arranged on the opposite side of the image display device 1 in the Y direction across the beam splitter 101K. The λ/4 plate 21A is arranged on the side of the main surface of the retroreflective member 2A where the beam splitter 101K is arranged. In other words, the λ/4 plate 21A is arranged on the light incident side of the retroreflective member 2A. The floating image 3K (shown in a dashed frame) is arranged in the horizontal direction (X-Y plane) between the housing 106 and the retroreflective member 2A, emerging from the beam splitter 101K in the Z direction upward. The floating image 3K is an aerial image formed in response to the beam splitter 101K. The floating image 3K is also an aerial image having a curved surface in response to the shape of the beam splitter 101K.

An opening 1061 is provided on the left side surface of the housing 106 in the Y direction and on the right side surface of the housing 4001 in the Y direction. The opening 1061 is a portion through which the image light from the image display device 1 passes or is transmitted. A transparent member or the like may be provided in the opening 1061. The image light corresponding to the image displayed on the image display device 1, more specifically the liquid crystal display panel 11, passes through this opening 1061 and travels toward the beam splitter 101K located to the left (negative direction) in the Y direction.

As with the configuration described above (Figure 3), the beam splitter 101K has the property of transmitting P-polarized light and reflecting S-polarized light. For example, it can be formed by evaporating an optical thin film onto a curved glass substrate or resin substrate. In this case, the angle of incidence of the polarized light on the beam splitter 101K changes depending on the angle of the curved surface, centered around approximately 45 degrees, and a floating image 3K is generated that is positioned almost horizontally (X-Y plane).

15A, an example of image light emitted from the image display device 1 through the opening 1061 in the negative direction in the Y direction is shown by a dashed arrow, and the dashed arrow of the optical axis K1 is used as a representative example. The image light emitted from the liquid crystal display panel 11 is light having a predetermined polarization characteristic, for example, P polarization (parallel polarization: P is an abbreviation for Parallel). This P-polarized image light passes through the beam splitter 101K on the optical axis K1 in the negative direction (left) in the Y direction, and proceeds toward the retroreflective member 2A on the optical axis K2 corresponding to the optical axis K1. The beam splitter 101K has the property of passing P-polarized light and reflecting S-polarized light (vertical polarization: S is an abbreviation for Senkrecht). The curved surface of the beam splitter 101K that transmits P-polarized light on this optical axis K1 forms an angle greater than the previously mentioned angle α ≒ approximately 45 degrees as shown in the figure.

A λ/4 plate 21A is provided on the light incidence surface of the retroreflective member 2A. The P-polarized image light of optical axis K1 emitted from the image display device 1 and transmitted through the beam splitter 101K passes through the λ/4 plate 21A twice, once before and once after being reflected by the retroreflective member 2A, and is converted from P-polarized to S-polarized light. As a result, the S-polarized image light traveling on optical axis K2 after reflection by the retroreflective member 2A is reflected by the beam splitter 101K and travels on optical axis K3 in the Z direction. Since the angle of incidence of the optical axis K2 with respect to the curved reflecting surface of the beam splitter 101K is smaller than the aforementioned angle of approximately 45 degrees, this S-polarized image light advances in a direction slightly tilted in the -Y direction from the Z direction straight up (approximately 90 degrees) as shown in the figure, and passes through the outside of the opening 4002, the transparent member 100, and the absorptive polarizing plate 112 to generate and display a real image, a floating image in space 3K, at a predetermined position in the Z direction. The other image light of the dashed arrows emitted in the negative direction in the Y direction also behaves in the same way as the aforementioned optical axes K1 and K2, but the angle of incidence of the S-polarized image light reflection corresponding to the optical axis K2 with respect to the curved reflecting surface of the beam splitter 101K differs depending on the reflection position on the surface of the beam splitter 101K. For this reason, the S-polarized reflected image light travels in the Z direction, but as in the example shown in Figure 15A (A), depending on the reflection position on the surface of the beam splitter 101K, it travels in a direction tilted from the -Y direction to +Y rather than the Z direction straight up (approximately 90 degrees), generating and displaying a real image, a floating-in-space image 3K, at a specified position in the Z direction.

The predetermined position where the floating image 3K is formed is determined according to the optical distance of the optical path of the optical system including the image display device 1, the beam splitter 101K, and the retroreflective member 2A. The distance between the floating image 3K and the beam splitter 101K is approximately equal to the distance between the image display device 1 and the beam splitter 101K. Since the beam splitter 101K has the semi-cylindrical shape described in FIG. 14(B) above, the shape of the floating image 3K is also approximately semi-cylindrical. In other words, it is a shape that extends the circular curve of the Y-Z cross section in the -X direction. Therefore, when viewed from the direction K, the user 230K can see the floating image 3K with the center part along the X-axis rising convexly in the traveling direction of the light that forms the floating image.

Figure 15B is a diagram showing an example of the configuration of a space-floating image display device suitable for installation on a desk, according to one embodiment (Eighth embodiment). Figure 15B shows a configuration in which beam splitter 101M replaces beam splitter 101K in space-floating image display device 400 of the embodiment of Figure 15A. Figure 15B (A) shows a Y-Z cross-sectional view, and Figure 15B (B) shows the configuration of beam splitter 101M. In this embodiment, differences from the embodiment of Figure 15A are explained, and repeated explanations of the same configuration as in Figure 15A are omitted.

Beam splitter 101M is a semi-cylindrical plate material of beam splitter 101K in FIG. 14(B) that is surrounded by the pair of straight sides A1, A1' and a pair of curved sides B1, B1', and the curved sides B1, B1' are configured with polygonal approximate curves BM1 and BM1'. In this embodiment, multiple rectangular beam splitter pieces are arranged in a staircase pattern to configure the staircase approximate curves BM1 and BM1' parallel to the bottom surface of beam splitter 101M and the corresponding approximate curved surfaces.

In this embodiment, the beam splitter 101M is disposed in the housing 4001 at an angle to the desk surface. One straight side (e.g., A1) of the beam splitter 101M is disposed near the image display device 1, and the other straight side (e.g., A1') of the beam splitter 101M is disposed near the retroreflective member 2A. The angle formed by the direction of the line segment connecting both ends of the arc of the approximate curved side surface of the beam splitter 101M corresponds to the Y direction of the desk surface (X-Y plane), and for example, in FIG. 15B, the angle α, which is the angle, is about 45 degrees (≒45°). Since the stepped beam splitter pieces in this embodiment are disposed parallel to the bottom surface of the beam splitter 101M, the angle of each beam splitter piece is the same as the angle α, which is about 45 degrees (≒45°).

In FIG. 15B (A), an example of image light emitted from the image display device 1 in the negative direction in the Y direction is shown by a dashed arrow, and the dashed arrow of the optical axis M1 is used as a representative example for explanation. The image light emitted from the liquid crystal display panel 11 is light having a predetermined polarization characteristic, for example, P polarization. This P-polarized image light passes through the beam splitter 101M on the optical axis M1 in the negative direction (left) in the Y direction as it is, and proceeds toward the retroreflective member 2A on the optical axis M2 corresponding to the optical axis M1. The beam splitter 101M has the property of passing P-polarized light and reflecting S-polarized light. The rectangular beam splitter piece of the beam splitter 101M that transmits P-polarized light on this optical axis M1 has the aforementioned angle α ≒ approximately 45 degrees.

The P-polarized image light of optical axis M1 that has passed through beam splitter 101M is converted from P-polarized to S-polarized light by passing through retroreflective member 2A and λ/4 plate 21A. As a result, the S-polarized image light that has traveled along optical axis M2 after reflection by retroreflective member 2 is reflected by beam splitter 101M and travels along optical axis M3 in the Z direction. Since the angle of incidence of optical axis M2 with respect to the reflecting surface of beam splitter 101M is approximately 45 degrees as described above, this S-polarized image light travels in the Z direction directly above (approximately 90 degrees) as shown in the figure, passes through the outside of opening 4002, transparent member 100, and absorptive polarizing plate 112, and generates and displays a real image floating in space 3M at a predetermined position in the Z direction. The S-polarized reflected image light from the other image light indicated by the dashed arrows that is emitted in the negative direction in the Y direction also travels in the Z direction, and a real image, a floating-in-space image 3M, is generated and displayed at a predetermined position in the Z direction, as in the example shown in Figure 15B (A).

The predetermined position where the floating image 3M is formed is determined according to the optical distance of the optical path of the optical system including the image display device 1, the beam splitter 101M, and the retroreflective member 2A. The distance between the floating image 3M and the beam splitter 101M is approximately equal to the distance between the image display device 1 and the beam splitter 101M. Since the beam splitter 101M has an approximate shape of a semi-cylinder as described above in FIG. 15B(B), the shape of the floating image 3M is also approximately a semi-cylinder. In other words, it is a shape that extends the stepped circular curve of the Y-Z cross section in the -X direction. Therefore, when viewed from the direction M, the user 230M can visually recognize the floating image 3M with a convex central part along the X-axis in the traveling direction of the light that forms the floating image.

Figure 15C is a diagram showing an example of the configuration of a space floating image display device suitable for installation on a desk according to one embodiment (Eighth embodiment). Figure 15C is configured by replacing the beam splitter 101K in the space floating image display device 400 of the embodiment of Figure 15A with a beam splitter 101L. Figure 15C (A) shows a Y-Z cross-sectional view, Figure 15C (B) shows an X-Y top view, and Figure 15C (C) shows an X-Z cross-sectional view. As described above in Figure 14 (C), the beam splitter 101L is a semi-cylindrical plate material obtained by rotating the beam splitter 101K of Figure 14 (B) by 90 degrees, and is surrounded by a pair of straight sides A2, A2' and a pair of curved sides B2, B2'. In this embodiment, differences from the embodiment of Figure 15A are explained, and repeated explanations of the same configuration as in Figure 15A are omitted.

In this embodiment, the beam splitter 101L is a semi-cylindrical plate material as shown in FIG. 14C, and is surrounded by a pair of straight sides and a pair of curved sides. In the housing 4001, the beam splitter 101L is disposed at an angle to the desk surface. The angle means that one curved side (e.g., B2) of the beam splitter 101L is disposed near the image display device 1, and the other curved side (e.g., B2') of the beam splitter 101L is disposed near the retroreflective member 2A. The angle formed by the straight sides A2 and A2' of the beam splitter 101L corresponds to the Y direction of the desk surface (X-Y plane), and for example, in FIG. 15C, the angle α, which is the angle of the angle, is about 45 degrees (≒45°). In this embodiment, the cylindrical surface between the pair of curved sides B2 and B2' is parallel to the straight sides A2 and A2', so the angle at which it is inclined is also about 45 degrees (≒45°).

The P-polarized image light on optical axis L1 that was transmitted through beam splitter 101L is converted from P-polarized to S-polarized light by passing through retroreflective member 2A and λ/4 plate 21A. As a result, the S-polarized image light that traveled on optical axis L2 after being reflected by retroreflective member 2 is reflected by beam splitter 101L and travels on optical axis L3 in the Z direction.

Since the angle of incidence of optical axis L2 with respect to the reflecting surface of beam splitter 101L is approximately 45 degrees as mentioned above, this S-polarized image light travels in the Z direction directly upward (approximately 90 degrees) as shown, passes through the outside of opening 4002, transparent member 100, and absorptive polarizing plate 112, and generates and displays a real image floating in space 3L at a predetermined position in the Z direction. The other S-polarized reflected image light from the image light of the dashed arrows emitted in the negative direction in the Y direction also travels in the Z direction, and generates and displays a real image floating in space 3L at a predetermined position in the Z direction, as in the example shown in Figure 15C (A).

The predetermined position where the floating image 3L is formed is determined according to the optical distance of the optical path of the optical system including the image display device 1, the beam splitter 101L, and the retroreflective member 2A. The distance between the floating image 3L and the beam splitter 101L is approximately equal to the distance between the image display device 1 and the beam splitter 101L. Since the beam splitter 101L has a semi-cylindrical shape as described above in FIG. 14(C), the shape of the floating image 3L is also approximately semi-cylindrical. In other words, it is a shape that extends the circular curve of the X-Z cross section in the Y direction. Therefore, when viewed from the direction L, the user 230L can visually recognize the floating image 3L with the center part along the Y axis rising convexly in the traveling direction of the light that forms the floating image.

Figure 15D is a diagram showing an example of the configuration of a space floating image display device suitable for installation on a desk according to one embodiment (Eighth embodiment). Figure 15D is configured by replacing the beam splitter 101K in the space floating image display device 400 of the embodiment of Figure 15A with a beam splitter 101N. The beam splitter 101N is arranged so that one straight side of the beam splitter 101N is near the display panel 11 and the other straight side of the beam splitter 101N is near the retroreflective member 2A. Figure 15D (A) shows a Y-Z cross-sectional view, Figure 15D (B) shows an X-Y top view, Figure 15D (C) shows an X-Z cross-sectional view, and Figure 15D (E) shows the configuration of the beam splitter 101N. In this embodiment, differences from the embodiment of Figure 15A are explained, and repeated explanations of the same configuration as in Figure 15A are omitted.

Beam splitter 101N is a semi-cylindrical plate material with a shorter distance between straight sides A1 and A1' of beam splitter 101K in FIG. 14B and a larger curvature, and is surrounded by a pair of straight sides AN1, AN1' and a pair of curved sides BN1, BN1'. Inside housing 4001, beam splitter 101N is disposed at an angle to the desk surface. "Diagonally" means that one straight side (e.g. AN1) of beam splitter 101N is disposed near the image display device 1, and the other straight side (e.g. AN1') of beam splitter 101N is disposed near the retroreflective member 2A. The angle formed by the direction of the line segment connecting both ends of the arc of the curved edge surface of beam splitter 101N corresponds to the Y direction of the desk surface (X-Y plane); for example, in FIG. 15D, the oblique angle α is about 45 degrees (≒45°).

As with the configuration described above (Figure 3), the beam splitter 101N has the property of transmitting P-polarized light and reflecting S-polarized light. For example, it can be formed by evaporating an optical thin film onto a curved glass substrate or resin substrate. At this time, the angle of incidence of the polarized light on the beam splitter 101N changes depending on the angle of the curved surface, centered around approximately 45 degrees, and a floating image 3N in space is generated that is positioned almost horizontally (X-Y plane).

The P-polarized image light on optical axis N1 that was transmitted through beam splitter 101N is converted from P-polarized to S-polarized light by passing through retroreflective member 2A and λ/4 plate 21A. As a result, the S-polarized image light that traveled on optical axis N2 after being reflected by retroreflective member 2 is reflected by beam splitter 101N and travels on optical axis N3 in the Z direction.

When the incidence angle of the optical axis N2 with respect to the reflective curved surface of the beam splitter 101N is approximately 45 degrees as mentioned above, this S-polarized image light travels in the Z direction directly upward (approximately 90 degrees) as shown in the figure, passes through the outside of the opening 4002, the transparent member 100, and the absorptive polarizing plate 112, and generates and displays a real image, a floating-in-space image 3N, at a predetermined position in the Z direction.

The other image light beams N12 and N13 indicated by dashed arrows that are emitted in the negative Y direction also behave in a similar manner to the optical axes N1 and N2 described above, but the S-polarized image light reflected by the curved reflecting surface of the beam splitter 101N, which corresponds to the optical axis N2, has a different angle of incidence depending on the reflection position on the surface of the beam splitter 101N.

For this reason, the reflected S-polarized image light travels in the Z direction, but as in the example shown in Figure 15D (A), the reflection angle of the S-polarized light differs depending on the reflection position on the surface of the beam splitter 101N. Since the incident angle of N22, which is on the bottom side of the optical axis N2, is smaller than 45 degrees, it travels to N32, which is tilted in the -Y direction from the Z direction directly above (approximately 90 degrees), and since the incident angle of N23, which is on the top side of the optical axis N2, is larger than 45 degrees, it travels to N33, which is tilted in the +Y direction from the Z direction directly above (approximately 90 degrees), and a real image, a floating-in-space image 3N, is generated and displayed at a specified position in the Z direction.

The predetermined position where the floating image 3N is formed is determined according to the optical distance of the optical path of the optical system including the image display device 1, the beam splitter 101N, and the retroreflective member 2A. The distance between the floating image 3N and the beam splitter 101N is approximately equal to the distance between the image display device 1 and the beam splitter 101N. Since the beam splitter 101N has a semi-cylindrical shape as shown in FIG. 15D(E), the shape of the floating image is also approximately semi-cylindrical, but since the curvature is larger than that of the beam splitter 101K in FIG. 15A described above, the floating image in the space is greatly tilted in the +Y direction and the -Y direction, that is, the floating image in the space 3N is obtained which is more enlarged than the shape of the beam splitter 101N. Therefore, when viewed from the direction N, the user 230N can see the floating image 3N which is enlarged more than the display image of the image display device 1, with the center part along the X-axis rising in a convex shape.

Figure 15E is a diagram showing an example of the configuration of a space floating image display device suitable for installation on a desk according to one embodiment (Eighth embodiment). Figure 15E is configured by replacing the beam splitter 101N in the space floating image display device 400 of the embodiment of Figure 15D with a beam splitter 101P. Figure 15E (A) shows the Y-Z cross-sectional view, Figure 15E (B) shows the X-Y top view, and Figure 15E (C) shows the X-Z cross-sectional view. The beam splitter 101P is a cone-shaped or lens-shaped plate material as shown in Figure 14 (D), with the bottom peripheral portion B3 surrounded by a circle or curve, and the side surface rising obliquely toward the apex of the plate material. In addition, the beam splitter 101P is arranged at a predetermined angle so that the bottom surface of the beam splitter 101P faces the display panel 11 and the apex of the beam splitter 101P faces the retroreflective member 2A. In this embodiment, we will explain the differences from the embodiment in Figure 15D, and will not repeat the explanation of the configuration similar to that in Figure 15D.

The beam splitter 101P is disposed in the housing 4001 at an angle to the desk surface. "At an angle" means that one curved side AA of the beam splitter 101P is disposed near the image display device 1, and the other curved side BB opposite the curved side is disposed near the retroreflective member 2A. The angle formed by the direction of the line segment connecting one curved side AA and the other curved side BB of the beam splitter 101P described above corresponds to the Y direction of the desk surface (X-Y plane), and for example, in FIG. 14, the angle α, which is the angle of the angle, is about 45 degrees (≒45°).

As with the configuration described above (Figure 15D), beam splitter 101P has the property of transmitting P-polarized light and reflecting S-polarized light. For example, it can be formed by evaporating an optical thin film onto a curved glass substrate or resin substrate. In this case, unlike the cylindrical shape of beam splitter 101N described above, beam splitter 101P has a curved surface surrounded by curves in the shape of a lens, so that S-polarized light that is reflected by beam splitter 101P is not only reflected in the ±Z directions, but also in the ±X directions, generating a floating image 3P positioned approximately on the X-Y plane.

The P-polarized image light on optical axis P1 that was transmitted through beam splitter 101P is converted from P-polarized to S-polarized light by passing through retroreflective member 2A and λ/4 plate 21A. As a result, the S-polarized image light that traveled on optical axis P2 after being reflected by retroreflective member 2 is reflected by beam splitter 101P and travels on optical axis P3 in the Z direction.

When the angle of incidence of the optical axis P2 with respect to the reflective curved surface of the beam splitter 101P is approximately 45 degrees as mentioned above, this S-polarized image light travels in the Z direction directly upward (approximately 90 degrees) as shown in the figure, passes through the outside of the opening 4002, the transparent member 100, and the absorptive polarizing plate 112, and generates and displays a real image, a floating image 3P, at a predetermined position in the Z direction.

The other image lights P12 and P13, indicated by dashed arrows, emitted in the negative Y direction behave in the same way as in FIG. 15D, generating the floating images PA and PB. Also, the image lights P14 and P15 are reflected in the ±X directions to generate the floating images PC and PD.

The predetermined position where the floating image 3P is formed is determined according to the optical distance of the optical path of the optical system including the image display device 1, the beam splitter 101P, and the retroreflective member 2A. The distance between the floating image 3P and the beam splitter 101P is approximately equal to the distance between the image display device 1 and the beam splitter 101P. Since the beam splitter 101P has a curved surface surrounded by the curved lens shape described in FIG. 14(D), the shape of the floating image in the space is similar to a circle, and since the curvature in the ±X direction is larger than that of the beam splitter 101N in FIG. 15D described above, the floating image in the space is greatly tilted in the +Y direction and the -Y direction, and the +X direction and the -X direction, that is, a floating image in the space 3P that is greatly enlarged is obtained compared to the shape of the beam splitter 101P. Therefore, when viewed from direction P, user 230P can see a floating image 3P that is larger than the image displayed on the image display device 1, with the center part rising convexly on the X-Y plane in the direction of travel of the light that forms the floating image.

Figure 15F is a diagram showing an example of the configuration of a space-floating image display device suitable for installation on a desk, according to one embodiment (Eighth embodiment). Figure 15F has the same optical configuration as the embodiment of Figure 15A in which a beam splitter 101K is arranged inside the space-floating image display device 400, but has a function of correcting image distortion of the floating image generated by the reflected light reflected by the retroreflective member via the curved surface of the beam splitter 101K. In this embodiment, differences from the embodiment of Figure 15A are explained, and repeated explanation of the same configuration as Figure 15A is omitted.

Figure 15F (1) shows in more detail the behavior of the image light in an optical configuration having the curved beam splitter 101K of Figure 15A described above. As shown in the Y-Z cross-sectional view (A) of Figure 15F (1), the display device 1 displays P-polarized image light P1 to P7 traveling in the -Y direction at equal intervals. When an observer (not shown) views the space-floating image 3K from the front of the device, the S-polarized image light that generates and displays the space-floating image 3K has a wide interval between the image light S3 and the image light S4 near the central convex part as shown in the top view (B) of Figure 15F (1), and the interval becomes narrower as it approaches both ends (the display device 1 side or the retroreflective member 2A side), such as between the image light S1 and the image light S2, or between the image light S6 and the image light S7, etc. In other words, it is visually recognized as a space-floating image 3K with image distortion.

This phenomenon occurs because the beam splitter 101K has a curved surface, and the angle of incidence varies depending on the reflection position of the S-polarized image light on the surface of the beam splitter 101K. As a result, the reflected S-polarized image light travels in the Z direction, but depending on the reflection position on the surface of the beam splitter 101K, it travels in a direction tilted in the -Y direction or +Y direction from the Z direction straight up (approximately 90 degrees), and a real image floating in space 3K is generated and displayed at a specified position in the Z direction.

If such a floating-in-space image effect is not desired, for example, image light in which image distortion of the floating image has been corrected may be displayed from the display device 1. Image distortion correction of the floating image is performed by the image control unit 1160 in FIG. 10 described above, which controls image processing of the image signal input from the image signal input unit 1131 and the image signal to be stored in the memory 1109. Image processing is, for example, scaling processing that enlarges, reduces, transforms, etc. the image.

Figure 15F (2) shows an embodiment for correcting image distortion of a floating image. As shown in the (A) Y-Z cross-sectional view of Figure 15F (2), image processing is performed by the image control unit 1160 from the display device 1, and P-polarized image light that has been corrected so that the closer to the center, the narrower the interval is, like the interval between image light P3' and image light P4', and the closer to both ends (the Z direction side of the display device 1 and the -Z direction side of the display device 1), the wider the interval is, like the interval between image light P1' and image light P2', or between image light P6' and image light P7', etc., travels in the -Y direction. When an observer (not shown) looks at the generated and displayed floating image 3K' from the front of the device, as shown in the top view of FIG. 15F(2)(B), the image light S3' and image light S4' near the central convex part, the image light S1' and image light S2' at both ends, and the image light S6' and image light S7' are all equally spaced, and are visually recognized as floating image 3K' without image distortion.

This correction is realized by correcting the interval of the image light on the display device 1 in advance so that even if there is a difference in the angle of incidence depending on the reflection position of the S-polarized image light on the curved surface of the beam splitter 101K, the image will be equally spaced on the floating image 3K'. Therefore, depending on the reflection position on the surface of the beam splitter 101K, the reflected image light of S-polarized light travels in a direction tilted in the -Y direction or +Y direction from the Z direction directly above (about 90 degrees), but the floating image 3K', which is a real image with equal intervals at a predetermined position in the Z direction, is generated and displayed, and the observer can view it as the floating image 3K' without image distortion. This correction is not limited to the embodiment of FIG. 15A, and it is possible to generate and display a floating image without distortion for the embodiments of FIG. 15B to FIG. 15E.

As described above, the space-floating image display device of each embodiment and modification can display a space-floating image with high visibility, suitable for use indoors, for example. Furthermore, the space-floating image display device of this embodiment is configured so that the spatial image displayed is curved, improving the impressive display and operability. More specifically, the beam splitter is configured to have a curved surface, and is configured to display a space-floating image with a curved surface. In this way, by making the polarization separation member non-planar, it is possible to form a non-planar floating image.

This has the effect of improving the visibility and operability of the floating-in-space image for the user. When the generated floating-in-space image is used as a non-contact user interface, it provides users with more impressive visibility and operability, and prevents or reduces operational errors and input errors.

The technology in this embodiment displays the floating image in a floating state with high resolution and high brightness, making it possible to use the floating image as a contactless user interface, allowing users to operate it without worrying about contact infection. This contributes to the "3 Health and Well-being for All" 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 retroreflective material, making it possible to obtain a bright and clear floating image 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 "9th Sustainable Development Goal: Build resilient infrastructure and promote inclusive and sustainable development" of the Sustainable Development Goals (SDGs) proposed by the United Nations.

Furthermore, the technology according to the embodiment makes it possible to form a floating image using highly directional (linear) image light. The technology according to the present embodiment makes it possible to provide a non-contact user interface with less risk of people other than the user peering at the floating image, even when displaying images that require high security, such as images displayed on so-called kiosk terminals, or highly confidential images that should be kept secret from people directly facing the user, by displaying highly directional image light. By providing the above-mentioned technology, the present invention contributes to "Sustainable cities and towns" in the Sustainable Development Goals (SDGs) proposed by the United Nations.

1: Image display device, 2, 2A, 2B: Retroreflective member, 3, 3A, 3B, 3C, 3D, 3E, 3F, 3J: Space floating image, 11: Liquid crystal display panel, 12, 112: Absorption type polarizing plate, 13: Light source device, 21, 21A, 21B: λ/4 plate, 203: Light guide, 100, 100A, 100B, 100C: Transparent member, 101, 101A, 101B, 101C, 101D, 101E, 101F, 101J, 101G, 101K, 101L, 101M, 101N, 101P: Beam splitter (polarization separation member), 1010: Beam splitter angle adjustment unit, 106: Image display device Housing of the placement unit, 300: image display unit, 400: space floating image display unit, 1061: opening, 4001: housing, 4002: opening, 230A, 230B, 230C, 230D, 230E, 230F, 230J, 230K, 230M, 230L, 230N, 230P: user, 310: piston mechanism, 310A, 310B, 310C: piston, 330, 331, 332, 333: hinge mechanism, 500: control unit, etc., 510: imaging unit, 600: unwanted light, 1110: control unit, 1160: image control unit, 1350: mid-air operation detection unit, 1351: mid-air operation detection sensor

Claims (14)

A floating-in-the-air image display device,
A display panel for displaying an image;
a polarization separation member that reflects a portion of the image light emitted from the display panel;
a retroreflective member disposed opposite the display panel and configured to retroreflect light reflected by the polarization separation member;
The light reflected by the retroreflective member forms a floating image through the polarization separation member,
The polarization separation member is made to have a non-planar shape, thereby forming the floating image in a non-planar shape.
A floating image display device. 2. The airborne image display device according to claim 1,
The non-planar shape is a curved shape.
A floating image display device. 2. The airborne image display device according to claim 1,
The non-planar shape is a semi-cylindrical shape and is bounded by a pair of straight sides and a pair of curved sides.
A floating image display device. 2. The airborne image display device according to claim 1,
The non-planar shape is a cone shape or a lens shape.
A floating image display device. 2. The airborne image display device according to claim 1,
The non-planar shape is stepped.
A floating image display device. 4. The airborne image display device according to claim 3,
The polarization separation member is disposed such that one straight side of the polarization separation member is adjacent to the display panel and the other straight side of the polarization separation member is adjacent to the retroreflective member.
A floating image display device. 4. The airborne image display device according to claim 3,
In the traveling direction of the light forming the floating-in-the-air image, the center of the floating-in-the-air image is higher than the vicinity of the display panel of the floating-in-the-air image and the vicinity of the retroreflective member of the floating-in-the-air image;
A floating image display device. 4. The airborne image display device according to claim 3,
The floating image is larger than the size of the polarization separation member.
A floating image display device. 4. The airborne image display device according to claim 3,
The polarization separation member is disposed such that one curved side of the polarization separation member is adjacent to the display panel and the other curved side of the polarization separation member is adjacent to the retroreflective member.
A floating image display device. 4. The airborne image display device according to claim 3,
In the traveling direction of the light forming the floating-in-the-air image, the curved side of the polarization separation member near the display panel and the curved side of the polarization separation member near the retroreflective member have high central portions.
A floating image display device. 5. The airborne image display device according to claim 4,
The bottom surface of the polarization separation member faces the display panel, and the apex of the polarization separation member faces the retroreflective member at a predetermined angle.
A floating image display device. 5. The airborne image display device according to claim 4,
The floating image is larger than the size of the polarization separation member.
A floating image display device. 2. The airborne image display device according to claim 1,
A function of correcting image distortion of the floating image,
A floating image display device. The airborne image display device according to claim 13,
The image distortion correction of the floating-in-the-air image is performed by displaying an image on the display panel that cancels out the distortion of the non-planar floating-in-the-air image.
A floating image display device.