Space suspension image display device

Abstract

The invention provides a technology capable of displaying a spatial floating image which is suitable for indoor use and has high visibility. According to the invention, it is beneficial to sustainable development of targets' 3. Health and welfare for all humans' and '9. Construction of a basis for industrial and technical innovation'. The spatial floating image display device is provided with a housing (106) which can be suitably arranged on the surface of a table or the like in a room and accommodates an image display device (1). A retro-reflection member (2) provided with a lambda / 4 plate (21) and a polarization separation member (101) (beam splitter) disposed at a predetermined angle are provided outside a housing (106). Image light of P-polarized light from an image display device (1) is converted into S-polarized light via a polarization separation member (101), a retro-reflection member (2) or the like, and a spatial floating image (3) is displayed at a predetermined position on the basis of the image light of the S-polarized light.

Description

Technical Field

[0001] The present disclosure relates to the technology of a spatial floating image display device. Background Art

[0002] As an example of a spatial floating image display device, Japanese Patent Publication No. 2019-128722 (Patent Document 1) can be cited. Patent Document 1 states that "the CPU of the information processing device has: an approach direction detection unit that detects the approach direction of the user to the image formed in the air; an input coordinate detection unit that detects the coordinates of the detected input; an operation acceptance unit that processes the acceptance of the operation; and an operation screen update unit that updates the operation screen according to the accepted operation. When the user approaches the image from a predetermined direction, the CPU accepts the user's action as an operation and performs processing corresponding to the operation."

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-128722 Summary of the invention

[0006] Problems to be solved by the invention

[0007] Although the spatial floating image display device such as Patent Document 1 can improve the operability of the spatial floating image, it does not consider improving the resolution and contrast of the appearance of the spatial floating image. There is a real situation that the spatial floating image is required to further improve the image quality.

[0008] The spatial floating image display device has a wide range of uses. If used as a signboard (advertising billboard), it can attract the attention of many people due to the novelty of "images floating in space" that was not available in previous flat-panel displays. In addition, as described in Patent Document 1, if the spatial floating image is used as a human-machine interface for performing certain operations, the non-contact feature can prevent virus infection through contact parts such as buttons. Moreover, if the spatial floating image display device can be simply set up in one's own study, living room, or workplace, the text, graphics, or dynamic images that were previously only displayed on a liquid crystal screen can be displayed as a spatial floating image, which is also pleasant in appearance and is also preferred as interior decoration.

[0009] On the other hand, when the spatial floating image display device is used indoors, especially in a living room where a family gathers, an office where at least a plurality of people exist in the workplace, etc., the spatial floating image is preferably visible only to a specific individual (hereinafter referred to as a user) to be used. However, as described later, there is a problem that the image light emitted from the image source as the source of the spatial floating image can also be seen by a person opposite to the position of the user's eyes. In order to solve this problem, it is desired that the image light cannot be visually recognized by a person other than the user who is located on the opposite side of the user's eyes.

[0010] The purpose of the present disclosure is to provide a technology for preventing a person on the opposite side of the user's eyes from visually recognizing the image light when the user visually recognizes the spatial floating image. In addition, the purpose of the present disclosure is to provide a technology for displaying a spatial floating image that is suitable for indoor use and has high visual recognition.

[0011] Means for solving problems

[0012] In order to solve the above-mentioned problems, for example, a structure described in the scope of the patent protection requested is adopted. The present application includes multiple means for solving the above-mentioned problems. If an example is cited, it is as follows. A spatial suspended image display device of one embodiment is a spatial suspended image display device for displaying a spatial suspended image, which is provided with: a retroreflective component, which is arranged opposite to the image display device, and a λ / 4 plate (phase difference plate, quarter wavelength plate) is arranged on the retroreflective surface; and a polarized light separation component, which is arranged at a predetermined angle relative to the image display device and the retroreflective component in the space connecting the above-mentioned image display device and the above-mentioned retroreflective component. The above-mentioned image display device has a light source device and a liquid crystal display panel as an image source, and the image light of a specific polarized wave emitted from the above-mentioned liquid crystal display panel, specifically, the image light of P polarized light, is transmitted from the above-mentioned polarized light separation component (also called a beam splitter), reflected by the above-mentioned retroreflective component, and passes through the above-mentioned λ / 4 plate twice, thereby polarization conversion into the image light of S polarized light. As a result, the image light of S polarized light reflected by the retroreflective component is reflected by the above-mentioned polarized light separation component, and based on the reflected image light, a spatial suspended image as a real image is displayed at a predetermined position.

[0013] Here, when the image light of the P polarized light is transmitted through the beam splitter, a part of the image light of the P polarized light is not transmitted through the beam splitter but is reflected. This causes a problem that a part of the reflected image light reflected by the beam splitter can be visually recognized by a person located at the back side of the spatial floating image display device, more specifically, at the side opposite to the position of the eyes of the user who visually recognizes the spatial floating image.

[0014] The spatial floating image display device of this embodiment is configured to not generate the above-mentioned reflected image light reflected by the above-mentioned beam splitter, or to sufficiently reduce the light amount of the above-mentioned reflected image light. More specifically, the spatial floating image display device of this embodiment is configured to not generate the above-mentioned reflected image light by setting the incident angle of the above-mentioned image light (P-polarized light image light) to the beam splitter to a predetermined angle (Brewster's angle: θB).

[0015] Effects of the Invention

[0016] According to a representative embodiment of the present disclosure, regarding the display of a spatial floating image, when a user visually recognizes the spatial floating image, it is possible to prevent a person located on the side opposite to the position of the user's eyes from visually recognizing the image light. In addition, according to a representative embodiment, a spatial floating image suitable for indoor use and with high visual recognizability can be displayed. According to a representative embodiment, it is configured to display a bright and highly visually recognizable spatial floating image, and does not generate reflected image light generated by the image light that becomes the source of forming the spatial floating image being reflected by a beam splitter, or the amount of light of the reflected image light is sufficiently reduced. Thus, it is possible to provide a spatial floating image display device that has the effect that a person located on the opposite side of the position of the user's eyes cannot visually recognize the above-mentioned reflected image light. The above-mentioned issues and issues other than the above-mentioned issues, as well as the structures and effects for solving these issues, etc., will be clarified through the description of the following embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a diagram showing an example of how to use the spatial floating image display device according to one embodiment.

[0018] Figure 2 FIG. 1 is a diagram showing a V-shaped structure as an example of the main structure of a spatial floating image display device according to an embodiment.

[0019] Figure 3 FIG. 1 is a diagram showing a Z-type structure as an example of the main structure of a spatial floating image display device according to an embodiment.

[0020] Figure 4 It is a diagram showing an example of a detailed structure of a retroreflective member.

[0021] Figure 5 This is a characteristic diagram showing the relationship between the surface roughness of the retroreflective member and the blur amount of the retroreflected image (space floating image).

[0022] Figure 6 This is a diagram showing a structural example of an image display device according to an embodiment.

[0023] Figure 7FIG. 1 is a diagram showing an example of the external configuration of a spatial floating image display device according to an embodiment (first embodiment).

[0024] Figure 8 It is a diagram showing a structural example of a cross section viewed from a horizontal direction in a spatial floating image display device according to an embodiment (first embodiment).

[0025] Fig. 9 It is a diagram showing an example of the external structure of a spatial floating image display device according to an embodiment (second embodiment).

[0026] Fig.10 It is a diagram showing a structural example of a cross section viewed from a horizontal direction in a spatial floating image display device according to an embodiment (second embodiment).

[0027] Fig.11 It is a graph showing the relationship between the incident angle and the reflectivity, and the Brewster angle.

[0028] Fig.12 It is a diagram showing an example of the external structure of a spatial floating image display device according to an embodiment (third embodiment).

[0029] Fig.13 It is a diagram showing a structural example of a cross section viewed from a horizontal direction in a spatial floating image display device according to an embodiment (third embodiment).

[0030] Fig.14 This is a diagram showing an example of installing a λ / 2 plate in an image display device section in a spatial floating image display device according to an embodiment (a modified example of the second embodiment). DETAILED DESCRIPTION

[0031] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the accompanying drawings, in principle, the same symbols are marked for the same parts, and repeated descriptions are omitted. In the accompanying drawings, in order to facilitate the understanding of the invention, the performance of each component sometimes does not represent the actual position, size, shape, range, etc. In the description, when describing the processing based on the program, sometimes the program, function, processing unit, etc. are described as the main body, but the main body of their hardware is a processor, or a controller, device, computer, system, etc. composed of the processor, etc. The computer uses resources such as memory and communication interface appropriately through the processor, while executing the processing according to the program read out to the memory. Thus, the predetermined function, processing unit, etc. are realized. The processor is composed of semiconductor devices such as CPU / MPU and GPU, etc. The processor is composed of a device and circuit that can perform predetermined operations. The processing is not limited to software program processing, and can also be realized by a dedicated circuit. The dedicated circuit can apply FPGA, ASIC, CPLD, etc. The program can be pre-installed on the target computer as data, or it can be distributed from the program source as data and installed on the target computer. The program source may be a program distribution server on a communication network, or a non-temporary computer-readable storage medium, such as a memory card, a disk, etc. The program may also be composed of multiple modules. The computer system may also be composed of multiple devices. The computer system may also be composed of a client / server system, a cloud computing system, etc. Various data and information may be composed of structures such as tables and lists, but are not limited to these. Expressions such as identification information, identifiers, IDs, names, and numbers may be interchangeable.

[0032] <Implementation Method>

[0033] The spatial floating image display device of the embodiment is configured to have an image display device, a beam splitter as a polarization separation component, and a retroreflective component having a λ / 4 plate (phase difference plate, quarter wavelength plate) arranged on the retroreflective surface. The image display device is configured to have a light source device and a display panel or a liquid crystal display panel that emits image light of a specific polarization wave (for example, P polarization light) as an image source (image display element). The light source device generates light as a backlight source and supplies it to the liquid crystal display panel. A polarization separation component is arranged in a space connecting the liquid crystal display panel and the retroreflective component of the image display device. The polarization separation component has the property of transmitting image light of a specific polarization wave from the liquid crystal display panel toward the retroreflective component, and reflecting image light of another polarization wave (for example, S polarization light) after polarization conversion by the retroreflective component and the λ / 4 plate. The image light of the other polarization wave after reflection generates and displays a spatial floating image as a real image at a predetermined position in a direction different from that of the image display device.

[0034] In order to improve the contrast performance of the spatial floating image, the image display device may also be provided with a polarization conversion unit that makes the light from the light source device consistent with the polarization light in a specific direction. For example, the light source device includes: a point-shaped or planar light source; an optical element unit that reduces the divergence angle of the light from the light source; a polarization conversion unit (polarization conversion element, etc.) that makes the light from the light source consistent with the polarization light in a specific direction; and a light guide having a reflective surface that transmits the light from the light source to the liquid crystal display panel, and the image beam of the image light from the liquid crystal display panel is controlled according to the shape and surface roughness of the reflective surface of the light guide.

[0035] Although not limited, considering indoor use, the spatial floating image display device of the embodiment is configured to include: an image display device unit having a housing that can be installed on a desk; and a spatial floating image display unit formed of a frame structure.

[0036] The image display device section mainly includes a liquid crystal display panel and a light source (backlight).

[0037] The spatial floating image display unit is configured to have an optical system composed of a polarized light separation component and a retro-reflective component, etc. The optical system of this embodiment has a structure supported by a frame made of metal or resin.

[0038] [Space Suspended Image Display Device]

[0039] The following embodiments relate to a spatial floating image display device that can, for example, transmit an image based on image light from an image light source having a large area through a transparent member that divides a space, such as glass of a shop window, and display it as a spatial floating image inside or outside the space of a store. In addition, unlike the above-mentioned embodiments, it relates to a spatial floating image display device that uses an image based on image light from an image light source having a smaller area (for example, about 2 to 5 inches) for displaying a spatial floating image mainly indoors, using an optical system composed of a polarized light separation member (in other words, a polarization beam splitter or only a beam splitter) and a retroreflective plate, etc., which will be described later.

[0040] In the following description of the embodiments, the term "space floating image" is used to express an image floating in space. This term may be replaced by "aerial image", "air floating image", "space floating optical image of a display image", "air floating optical image of a display image", etc. The term "space floating image" used in the description of the embodiments is used as a representative example of these terms.

[0041] According to the following embodiments, for example, it is possible to display high-resolution image information in a spatially suspended state on the glass surface of a display window or a light-transmitting plate. In addition, the spatially suspended image display device of the embodiments can also be set on a desk in a study, on a table in a living room, or in a relatively small space such as a counter kitchen. In addition, according to the embodiments, it is possible to provide a spatially suspended image display device, in particular, a person who is on the opposite side of the spatially suspended image display device to a user who can visually recognize the spatially suspended image cannot visually recognize the reflected image light (details will be described later). According to the embodiments, in particular, it is possible to provide a spatially suspended image display device that is suitable as a display device for small internal objects or information equipment in the room.

[0042] In the prior art example of space floating image display device, an organic EL panel and a liquid crystal display panel as a high-resolution color display image source are used in combination with a retroreflective component. In the prior art example of space floating image display device, image light is diffused at a wide angle, so there are the following problems.

[0043] like Figure 4 As shown, in the retro-reflective component 2, since the retro-reflective portion 2a is a hexahedron, in addition to the reflected light of the regular reflection, there is also a problem of double images due to the image light incident from an oblique direction to the retro-reflective component 2, which damages the image quality of the spatial floating image. The retro-reflective component 2 is also called a retro-reflective plate or a retro-reflective sheet.

[0044] In addition, if Figure 5 As shown, the spatial floating image obtained by reflecting the image light from the image display device as the image source by the retroreflective member 2 has the problem of blurring of each pixel of the liquid crystal display panel in addition to the above-mentioned double image.

[0045] Figure 1 An example of usage and a configuration example of a spatial floating image display device according to an embodiment are shown. Figure 1 (A) represents the overall structure of the spatial floating image display device of the present embodiment. For example, in a store, etc., the space is divided by a display window (window glass) 105 which is a light-transmitting component such as glass (also recorded as a transparent component). According to the spatial floating information display device of the present embodiment, it is possible to transmit through the transparent component and display a spatial floating image in one direction relative to the outside of the store space. Specifically, light with a narrow-angle directional characteristic and a specific polarization wave is emitted from the image display device 1 in the spatial floating information display device as an image beam, temporarily incident on the retro-reflective component 2, retro-reflected, transmitted from the window glass 105, and formed as a real image on the outside of the store space. Figure 1In (A), the situation in which the inner side of the window glass 105 in the depth direction is the space inside the store and the front side is the space outside the store (for example, the sidewalk) is shown. On the other hand, by providing a unit (optical component, etc.) that reflects a specific polarized wave on the window glass 105, it is also possible to reflect the image beam and form a spatial floating image 3 at a desired position in the store.

[0046] Figure 1 (B) shows the module structure of the above-mentioned image display device 1. The image display device 1 includes: an image display unit 1a, which displays the original image of the spatial floating image 3; an image control unit 1b, which converts the input image according to the resolution of the panel of the image display unit 1a; an image signal receiving unit 1c, which receives the image signal; and a receiving antenna 1d. The image signal receiving unit 1c handles wired input signals such as USB (Universal Serial Bus: registered trademark) input and HDMI (High-Definition Multimedia Interface: registered trademark) input, and handles wireless input signals such as Wi-Fi (Wireless Fidelity: registered trademark). The image display device 1 can function as an image receiving / display device alone, and can also display image information from an external PC, tablet computer, smartphone, etc. Moreover, if the image display device 1 is connected to a stick PC, etc., it can also have the capabilities of calculation processing, image analysis processing, etc.

[0047] [V-type space floating image display device]

[0048] Figure 2 A configuration example of the main parts of a spatial floating image display device according to an embodiment is shown. Figure 2 The embodiment of the present invention shows that the image display device 1 and the retroreflective member (in other words, the retroreflective plate) 2 are arranged in a substantially V-shaped structure (hereinafter referred to as V-shaped). Figure 2 As shown in FIG. 1 , in a V-shaped structure, an image display device 1 for generating image light of a specific polarized wave is provided in an inclined direction (direction corresponding to the optical axis A1) relative to a transparent member 100 such as a flat glass (arranged in the horizontal direction in this example). In addition, a retro-reflective member 2 is provided in another inclined direction (direction corresponding to the 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 as a liquid crystal display element, an absorptive polarizing plate 12, and the like.

[0049] exist Figure 2In the embodiment, the image light of a specific polarized wave emitted from the liquid crystal display panel 11 of the image display device 1 travels along the direction of the optical axis A1, is reflected by the beam splitter 101 (polarized light separation component) provided on the transparent component 100 and having a film that selectively reflects the image light of a specific polarized wave, travels along the direction of the optical axis A2, and enters the retro-reflective component 2. In this example, the beam splitter 101 is formed in a sheet shape and bonded to the lower surface of the transparent component 100 such as a flat glass. Alternatively, the beam splitter 101 may be formed by directly evaporating an optical thin film on the flat glass.

[0050] The λ / 4 plate 21 is provided on the image light incident 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, or a quarter wavelength plate.

[0051] The image light on the optical axis A2 from the beam splitter 101 passes through the λ / 4 plate 21 twice in total when incident on the retro-reflective component 2 and when emitted from the retro-reflective component 2, thereby undergoing polarization conversion from a specific polarized wave (one polarized wave) to another polarized wave. Here, the beam splitter 101 that selectively reflects the image light of a specific polarized wave has the property of transmitting the image light of another polarized wave after polarization conversion. Therefore, the image light of another polarized wave after polarization conversion is transmitted from the beam splitter 101. The image light transmitted from the beam splitter 101 forms and displays a spatial suspended image 3 as a real image at a predetermined position outside the transparent component 100 in the direction of the optical axis A3 corresponding to the optical axis A2.

[0052] In addition, the light forming the space suspended image 3 is a collection of light rays that converge from the retro-reflective component 2 to the optical image of the space suspended image 3, and these light rays also go straight after passing through the optical image of the space suspended image 3. Figure 2 In the structure, when the user visually recognizes from the direction A indicated by the arrow corresponding to the optical axis A3, the space floating image 3 is visually recognized as a bright image. However, when other people visually recognize from the direction B indicated by the arrow, for example, the space floating image 3 is completely invisible as an image. Such a characteristic is very preferable in the case of a system that displays an image requiring high security or a highly confidential image that is to be kept secret from a person facing the user.

[0053] In addition, depending on the performance of the retro-reflective component 2, the polarization axis of the image light after reflection may become inconsistent. In this case, a portion of the image light with inconsistent polarization axis is reflected by the beam splitter 101 and returned to the image display device 1. The returned light is reflected again on the image display surface of the liquid crystal display panel 11 constituting the image display device 1, thereby generating a ghost image, which may reduce the image quality of the spatial suspended image 3. Therefore, in this embodiment, an absorptive 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 absorptive polarizing plate 12, and the reflected light returned from the beam splitter 101 is absorbed by the absorptive polarizing plate 12. As a result, the above-mentioned re-reflection can be suppressed, and the image quality reduction caused by the ghost image of the spatial suspended image 3 can be prevented.

[0054] The beam splitter (polarization separation means) 101 is formed of, for example, a reflective polarizing plate or a metal multilayer film that reflects a specific polarization wave, etc. More specifically, the beam splitter 101 can be formed by depositing an optical thin film on a flat glass (for example, quartz glass).

[0055] [Space Suspended Image Display Device Z Type]

[0056] Figure 3 Representation and Figure 2 An example of the structure of the main parts of a spatial floating image display device according to an embodiment that is different from the embodiments. Figure 3 The embodiment shows the following structure (hereinafter referred to as Z-type): the image display device 1 and the retroreflective component 2 (retroreflective plate) are arranged relative to each other, and in the space connecting them, the beam splitter 101 is at an angle of about 45 degrees relative to the image display device 1 and the retroreflective component 2, and is roughly arranged in a Z shape (or an inverted Z shape).

[0057] exist Figure 3 In the Z-type structure shown, a transparent member 100 such as a glass plate and an absorptive polarizing plate 112 are provided for the purpose of reducing the influence of external light incident from direction C on the retroreflective member 2 and the image display device 1. Figure 3 As shown, the image display device 1 and the retro-reflective component 2 are arranged at an angle of about 90 degrees with the transparent component 100 and the absorptive polarizer 112, and are arranged at an angle of about 45 degrees with the beam splitter 101. In this embodiment, the beam splitter 101 is arranged in the horizontal direction, 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 spatial floating image 3 is formed are in a plane-symmetrical positional relationship with the beam splitter 101.

[0058] [Retro-reflective components]

[0059] exist Figure 4In (A), as a representative retroreflective member 2, the surface shape of the retroreflective member 2 (retroreflective plate) manufactured by Nippon Carbide Industries Co., Ltd. used in this study is shown. Figure 4 (A) represents the top view, Figure 4 (B) shows a side view. The surface of the retro-reflective component 2 has a retro-reflective portion 2a composed of regularly arranged hexagonal prisms. Light incident on the interior of the retro-reflective portion 2a is reflected by the wall and bottom of the hexagonal prisms and emitted as retro-reflected light in a direction corresponding to the incident light. The emitted light is, for example, Figure 2 , Figure 3 In the structure shown in FIG. 1 , a spatial suspended image 3 is formed as a regular reflected image (regular image). Figure 4 As shown in (B), due to the image light obliquely incident on the retroreflective member 2 among the image light from the image display device 1, a ghost image (not shown) is formed at a position different from the regular image. The ghost image reduces the visibility of the spatial floating image 3.

[0060] Therefore, in this embodiment ( Figure 3 ), based on the image displayed on the image display device 1, a spatial floating image 3 is displayed as a real image without forming a double image. The resolution of the spatial floating image 3 mainly depends on the resolution of the liquid crystal display panel 11 and Figure 4 The outer diameter D and the pitch P of the retroreflective portion 2a of the retroreflective member 2 shown in (A). For example, in the case of a 7-inch WUXGA (1920×1200 pixels) liquid crystal display panel 11, even if one pixel (one triplet) is about 80 μm, for example, if the diameter D of the retroreflective portion 2a is 240 μm and the pitch P is 300 μm, one pixel of the spatial suspended image 3 is equivalent to 300 μm. Therefore, the effective resolution of the spatial suspended image 3 is reduced to about 1 / 3. Therefore, in order to make the resolution of the spatial suspended image 3 equal to the resolution of the image display device 1, it is desirable to make the diameter D and the pitch P of the retroreflective portion 2a close to one pixel of the liquid crystal display panel. On the other hand, in order to suppress the generation of moire fringes caused by the pixels of the retroreflective member 2 and the liquid crystal display panel 11, the pitch ratio of each can be designed to be not an integer multiple of one pixel. In addition, the shape can be a shape configured in a manner that neither side of the retroreflective portion 2a overlaps with any side of one pixel of the liquid crystal display panel 11.

[0061] The inventors of the present invention produced 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 the present embodiment, and experimentally determined the relationship between the image blur amount l (small L) of the spatial floating image 3 that can be allowed in order to improve visual recognizability and the pixel size L (large L). Figure 5 The experimental results are shown. It is known that the blur amount l that deteriorates the visual recognition is preferably less than 40% of the pixel size, and it is almost inconspicuous if it is less than 15%. It is known that the surface roughness of the reflective surface for which the blur amount l becomes an allowable amount is an average roughness of less than 160nm within the range of a measurement distance of 40μm. In order to make the blur amount l less noticeable, the surface roughness of the reflective surface is preferably less than 120nm. Therefore, it is desired to reduce the surface roughness of the above-mentioned retroreflective component 2, and set the surface roughness of the reflective film forming the reflective surface and the protective film including the same to less than the above-mentioned value.

[0062] On the other hand, in order to manufacture the retroreflective component 2 at a low price, a rolling method can be used to form it. Specifically, it is a method of shaping the retroreflective portion 2a by arranging it. In this method, the opposite shape of the shape to be shaped is formed on the roller surface, and an ultraviolet curing resin is applied to the base material for fixing, and it is passed between rollers to shape the necessary shape, and ultraviolet rays are irradiated to cure it, so as to obtain the retroreflective component 2 of the desired shape.

[0063] The image display device 1 of the present embodiment includes a liquid crystal display panel 11 and a light source device 13 (specifically, Figure 6 ), the possibility of the image light being incident obliquely with respect to the retroreflective member 2 becomes smaller. As a result, a system having an excellent structure is formed: the generation of ghost images is suppressed, and even if ghost images are generated, the brightness of the ghost images is low.

[0064] On the other hand, Figure 3 In the structure of the Z-type space floating image display device shown, the image display device 1, which is composed of a liquid crystal display panel 11, an absorption type polarizing plate 12 and a light source device 13, is arranged at a predetermined angle (for example, an angle of about 45 degrees relative 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 the optical axis B1 (the tilt direction relative to the beam splitter 101), and travels toward the retro-reflective component 2 in the direction of the optical axis B2 corresponding to the optical axis B1 (corresponding to the direction D).

[0065] Here, the image light from the image display device 1 is light of a specific polarization, for example, image light having the characteristics of P polarized light (parallel polarized light: Parallel Polarization). In addition, the beam splitter 101 is a polarized light separation component such as a reflective polarizing plate, which has the property of transmitting the image light of P polarized light from the image display device 1 but reflecting the image light of S polarized light (vertical polarized light: Senkrecht Polarization). The beam splitter 101 is formed by a reflective polarizing plate or a metal multilayer film that reflects a specific polarized wave. The beam splitter 101 can generally be formed by vapor-depositing an optical thin film on a flat glass substrate. Therefore, the refractive index of the beam splitter 101 is substantially the same as the refractive index n (n = about 1.5) of the flat glass.

[0066] On the other hand, the λ / 4 plate 21 is provided on the light incident surface (retroreflective surface) of the retroreflective component 2. The image light of the P polarized light transmitted from the beam splitter 101 from the image display device 1 passes through the λ / 4 plate 21 twice at the time of incidence and emission relative to the retroreflective component 2, thereby undergoing polarization conversion from the P polarized light to the S polarized light. As a result, the image light of the S polarized light after polarization conversion from the retroreflective component 2 is reflected by the beam splitter 101 and travels toward the transparent component 100 etc. The image light of the S polarized light traveling in the direction corresponding to the optical axis B3 after reflection (the tilted direction relative to the beam splitter 101) is transmitted from the transparent component 100 composed of a glass plate etc. and the absorptive polarizing plate 112, and a spatial floating image 3 as a real image is generated and displayed at a predetermined position outside the transparent component 100 etc.

[0067] Here, for the optical system composed of optical components such as the image display device 1, the retroreflective component 2, and the beam splitter 101, in order to reduce the image quality degradation caused by the incident sunlight and illumination light, an absorption type polarizing plate 112 can be provided on the outer surface of the transparent component 100. The light is retroreflected by the retroreflective component 2, and thus there is a case where the polarization axis is inconsistent, so there is a case where a part of the image light is reflected by the beam splitter 101 and returns to the image display device 1. The returned light is reflected again on the image display surface of the liquid crystal display panel 11 constituting the image display device 1, thereby generating a double image, which significantly reduces the image quality of the spatial floating image 3.

[0068] Therefore, in Figure 2 as well as Figure 3 In any of the embodiments shown, the image display surface of the image display device 1 is provided with an absorption type polarizing plate 12. Alternatively, an anti-reflection film (not shown) may be provided on the image emitting side surface of the absorption type polarizing plate 12 provided on the surface of the image display device 1. Thus, by absorbing the light that causes the generation of ghost images by the absorption type polarizing plate 12, the image quality degradation caused by the ghost images of the spatial floating images 3 can be prevented.

[0069] In addition, Figure 3 In the Z-type structure, when external light directly impinges on the retro-reflective component 2, a strong ghost image is generated. Therefore, in order to suppress and prevent the generation of the ghost image, in this embodiment, the retro-reflective component 2 is tilted downward relative to the incident direction of the external light, so as to become a structure that hinders the incidence of the external light. Specifically, the main incident direction of the external light is set to a direction (an inclined direction such as the optical axis B3) corresponding to the direction C shown by the arrow (the direction in which the user visually recognizes the spatial suspended image 3 from the front). In this case, the retro-reflective component 2 is configured so that the optical axis B2 has a relationship of, for example, about 90 degrees relative to the direction C (optical axis B3). In other words, the main surface of the retro-reflective component 2 is configured to have a relationship of, for example, about 90 degrees with the main surface of the transparent component 100, etc. As a result, the external light incident in the direction C will not directly impinge on the main surface (retro-reflective surface) of the retro-reflective component 2, so the generation of the ghost image can be prevented.

[0070] In addition, the image display device 1 is also arranged in a direction different from the incident direction (direction C) of the external light. Specifically, the main surface (image light exit surface) of the image display device 1 is arranged in the same direction as the main surface of the retroreflective component 2 (in other words, parallel), and the optical axis B1 of the image display device 1 is arranged at a relationship of about 90 degrees with respect to the optical axis B3 corresponding to the incident direction (direction C) of the external light. In addition, considering the range of the light beam when the external light is incident on the main surface of the transparent component 100 functioning as the opening portion in the direction C, the image display device 1 is arranged at a position slightly away from the outside of the range. Thereby, the generation of ghosting caused by re-reflection in the image display device 1 can be reduced.

[0071] [Image display device]

[0072] Figure 6 Indicates that it can be applied to Figure 2 , Figure 3 An example of the structure of an image display device 1 of an embodiment. The image display device 1 is configured to include a light source device 13, a liquid crystal display panel 11, a light direction changing panel 54, etc. The above-mentioned absorption-type polarizing plate 12 may also be provided on the image emitting surface side of the liquid crystal display panel 11. The light source device 13 is configured to include a plurality of LED elements 201 (LED: Light Emitting Diode) as semiconductor light sources (solid light sources) constituting the light source, and a light guide 203, etc. Figure 6 In FIG. 1 , a state in which the liquid crystal display panel 11 and the light direction changing panel 54 are arranged on the light emitting side of the light source device 13 is shown as a developed stereoscopic view.

[0073] The light source device 13 is formed of a housing (not shown) made of plastic or the like, and is constituted by accommodating the LED elements 201 and the light guide 203 inside. In order to convert the divergent light from each LED element 201 into a substantially parallel light beam, a light receiving end surface 203a is provided on the light incident side of the light guide 203. The light receiving end surface 203a has a shape in which the cross-sectional area gradually increases toward the opposite side relative to the light receiving part, and is provided with a lens shape that has the effect of gradually reducing the divergence angle by performing multiple total reflections during propagation inside.

[0074] Furthermore, a liquid crystal display panel 11 is mounted on the upper surface of the light guide 203 and arranged substantially parallel to the light guide 203. The upper surface of the light guide 203 is an exit surface from which light reflected by the light guide 203 is emitted. Figure 6 A plurality of LED elements 201 are mounted on the light guide 203 (the side surface being the lower side in the figure). Light from the plurality of LED elements 201 is converted into substantially collimated light (substantially parallel light) by the shape of the light receiving end surface 203a of the light guide 203. Therefore, the light receiving portion of the light receiving end surface 203a is mounted to maintain a predetermined positional relationship with the LED element 201.

[0075] The light source device 13 is composed of a light source unit in which a plurality of LED elements 201 as light sources are arranged on a light receiving portion, i.e., a light receiving end surface 203a, which is disposed on the light incident side of a light guide 203. The divergent light beam from the LED element 201 becomes approximately collimated light due to the lens shape of the light receiving end surface 203a of the light guide 203. The approximately collimated light is guided in the direction A indicated by the arrow inside the light guide 203. The direction A is a direction approximately parallel to the liquid crystal display panel 11 (a direction from bottom to top in the accompanying drawings). The light beam direction of the light guided in the direction A is changed by a light beam direction changing portion 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 a direction approximately perpendicular to the display surface of the liquid crystal display panel 11.

[0076] The light guide 203 has a structure that optimizes the distribution (in other words, density) of the light beam direction changing portion 204 by the shape of the interior or surface of the light guide 203. Thus, the uniformity of the light of the outgoing light beam from the light source device 13 shown in the direction B and the incident light beam to the liquid crystal display panel 11 can be controlled.

[0077] Moreover, in the image display device 1 including the light source device 13 and the liquid crystal display panel 11, in order to improve the utilization efficiency of the outgoing light beam from the light source device 13 shown in the direction B and significantly reduce the power consumption, the directivity of the light from the direction B of the light source device 13 can also be controlled. More specifically, as the light source device 13, a light source with a narrow divergence angle can be configured. As a result, the image light from the image display device 1 efficiently reaches the observer with high directivity (in other words, straightness) like a laser, and a high-quality spatial floating image can be displayed with high resolution. At the same time, the power consumption of the image display device 1 including the LED element 201 of the light source device 13 can be significantly reduced.

[0078] In addition, the liquid crystal display panel 11 mounted on the frame and the flexible printed circuits (FPC: Flexible Printed Circuits) electrically connected to the liquid crystal display panel 11 are mounted on the frame not shown of the liquid crystal display panel 11. The liquid crystal display panel 11 as a liquid crystal display element modulates the intensity of the transmitted light together with the LED element 201 based on a control signal from a control circuit not shown constituting the electronic device, thereby generating a display image.

[0079] <Desktop-mounted (Z-type) spatial floating image display device>

[0080] Next, use Figure 7 The following drawings illustrate a table-mounted spatial floating image display device according to an embodiment. The basic structure of the spatial floating image display device of each embodiment shown below is equivalent to Figure 3 In order to form the function of the space floating image 3, the components of the space floating image display device (image display device 1, beam splitter 101, retro-reflective component 2, etc.) are fixed to each other in a predetermined positional relationship.

[0081] [First embodiment]

[0082] Figure 7 An example of the external structure of a spatial floating image display device suitable for desktop setting according to an embodiment (first embodiment) is shown. Figure 7 The spatial floating image display device of the first embodiment shown generally comprises an image display device section 300 (a housing 106 corresponding thereto) and a spatial floating image display section 400. The image display device section 300 is mounted / stored in the housing 106 (in other words, a storage section of the image display device 1). The spatial floating image display section 400 includes a retro-reflective component 2, a λ / 4 plate 21, a beam splitter 101, a frame 108 supporting them, and the like.

[0083] exist Figure 7 In the figure, when the XY plane is set as a desktop (a horizontal plane in this example), a shell 106 is arranged on the desktop. The shell 106 is roughly a rectangular parallelepiped shape and a flat plate shape of a predetermined height. An image display device 1 is arranged along the desktop in the shell 106. A spatial floating image display unit 400 is arranged on the shell 106. The beam splitter 101 is arranged at an angle relative to the desktop. The retro-reflective component 2 and the λ / 4 plate 21 are arranged on the beam splitter 101 along the desktop. The λ / 4 plate 21 is arranged toward the lower side relative to the retro-reflective component 2 located on the upper side. That is, the λ / 4 plate 21 is arranged on the light incident side of the retro-reflective component 2. The spatial floating image 3 is formed to protrude forward (Y direction) from the beam splitter 101 between the shell 106 and the retro-reflective component 2 and stand upright in the vertical direction (XZ plane).

[0084] The spatial suspended image 3 is formed to protrude from the beam splitter 101 to the front side (Y direction) between the shell 106 and the retro-reflective component 2 and stand upright in the vertical direction (XZ plane). The shell 106 of the spatial suspended image display device is not limited to being configured at the bottom. Depending on the situation, the positional relationship between the shell 106 and the retro-reflective component 2 can be opposite, or can be configured left and right instead of up and down. That is, the beam splitter 101 is configured between the light exit side of the shell 106 and the retro-reflective component 2, the light exit side of the shell 106 and the light incident exit side of the retro-reflective component 2 are configured oppositely, and the beam splitter 101 is configured obliquely relative to the light incident exit surface of the retro-reflective component 2.

[0085] The frame 108 is a component that supports the beam splitter 101, the retroreflective component 2, and the λ / 4 plate 21. The frame 108 protrudes upward from two corners of the upper surface of the housing 106, extends obliquely upward along the two oblique sides of the beam splitter 101, bends in the horizontal direction (Y direction), extends along the two sides of the retroreflective component 2, etc., and then their ends extend along the X direction and are closed.

[0086] In this embodiment, the housing 106 contains and fixes Figure 6 The components of the image display device 1 are the light source device 13, the liquid crystal display panel 11 as a liquid crystal display element, the absorption type polarizing plate 12, etc. An opening 1061 is provided at the upper part of the housing 106. The opening 1061 is a portion through which the image light is transmitted. A transparent member or the like may be provided at the opening 1061. The image light corresponding to the image displayed on the image display device 1, more specifically, on the liquid crystal display panel 11, travels toward the beam splitter 101 above through the opening 1061.

[0087] Figure 7This is a perspective view of the appearance of the spatial floating image display device when viewed from the upper side (diagonally above). The front of the device here is a surface corresponding to the direction in which the user can visually recognize the spatial floating image 3 (indicated by a dotted frame) formed by the spatial floating image display unit 400 from the front. Direction F is the direction in which the user visually recognizes the spatial floating image 3 from the front, and corresponds to the negative direction of the Y direction.

[0088] For the purpose of explanation, a coordinate system and direction such as (X, Y, Z) as shown in the figure are sometimes used. The Z direction is the vertical direction and the up-down direction (the vertical direction in the screen of the spatial floating image 3), the X direction and the Y direction are two horizontal directions, the X direction is the left-right direction (the horizontal direction in the screen of the spatial floating image 3), and the Y direction is the depth direction and the front-back direction (the direction in which the user observes the spatial floating image 3).

[0089] In the present embodiment, as shown in the figure, the spatial floating image display unit 400 is configured so that the beam splitter 101, the retroreflective component 2, etc. are exposed and not covered by the shell. In addition, the shell 106 becomes relatively small (compact) and the thickness in the Z direction is suppressed to be thin. In the present embodiment, the spatial floating image display unit 400 is configured and fixed on the upper side of the shell 106 via the frame 108 as a pillar to support the beam splitter 101, the retroreflective component 2, etc. Therefore, when the spatial floating image display unit 400 (especially the spatial floating image 3) is observed from the user's viewpoint in the Y direction and the front (direction F), the shell that enters the user's field of view is only the thin shell 106. Therefore, this embodiment has few objects that block the user's field of view, and can improve the floating feeling of the spatial floating image 3 in the air, which is suitable for use.

[0090] The beam splitter 101 and the retro-reflective component 2 are sufficiently thin. The main surface of the retro-reflective component 2 made of a resin material is arranged along the X direction and the Y direction (for example, the horizontal direction). Therefore, when the spatial floating image 3 is visually recognized from the user's viewpoint in the Y direction and the front (direction F), the retro-reflective component 2 is not very obvious. In addition, when the spatial floating image 3 is not displayed and the spatial floating image display device is not used, when the spatial floating image display unit 400 is observed from the user's viewpoint along the Y direction (direction F), the beam splitter 101 appears as a translucent plate, and the back side of the beam splitter 101 can be visually recognized to some extent.

[0091] As described above, the beam splitter 101 has the property of transmitting P polarized light and reflecting S polarized light, and can be formed, for example, by vapor-depositing an optical film on a flat glass substrate. At this time, as the incident angle of the polarized light with respect to the beam splitter 101, an incident angle of about 45 degrees ± 15 degrees is generally used. In addition, the image display device unit 300, the beam splitter 101, and the retro-reflective component 2 are Figure 3The Z-shaped structure is similarly arranged and fixed with a predetermined positional relationship.

[0092] like Figure 7 As shown, the beam splitter 101 is arranged on the housing 106, that is, the upper side of the image display device section 300 or the light emitting side of the image display device section 300, via the frame 108 as a support, so as to form an inclined surface relative to the XY plane. In addition, the retro-reflective component 2 and the λ / 4 plate 21 are arranged on the XY plane relative to the beam splitter 101 via the frame 108 as a support. Here, two or three sides of the rectangular main surface of each of the beam splitter 101 and the retro-reflective component 2 are bonded and fixed to the frame 108 as the corresponding support. Then, as shown in the figure, a spatial floating image 3 is formed at a predetermined position near the front side in the Y direction relative to the beam splitter 101.

[0093] Figure 8 Indicates from the side, X direction ( Figure 7 E) Observe Figure 7 The internal structure of the cross-sectional view of the image display device unit 300 and the space floating image display unit 400. As shown in the figure, the image display device unit 300 and the space floating image display unit 400 have Figure 3 The Z-shaped structure. Figure 3 The structure is rotated in the figure so that Figure 3 When the direction D in the vertical direction (Z direction) is the vertical direction, in addition to the transparent member 100 and the absorbing polarizing plate 112, Figure 3 The structure and Figure 8 The structure becomes the same structure.

[0094] exist Figure 8 In the image display device section 300, that is, the housing 106 and the image display device 1 accommodated in the housing 106, the image light from the liquid crystal display panel 11 is arranged in a direction that is emitted upward in the Z direction. That is, the image display surface of the liquid crystal display panel 11 is arranged in the XY plane (horizontal plane). In addition, in the housing 106, the light source device 13, the liquid crystal display panel 11, and the absorption type polarizing plate 12 are arranged in order from the bottom. Figure 8 In FIG. 1 , the image light emitted upward from the image display device 1 through the opening 1061 to the optical axis C1 is shown by the dotted arrows. The center of the three dotted arrows indicates the optical axis, and the left and right sides indicate the range of the light beam.

[0095] The image light emitted from the liquid crystal display panel 11 is a light having a predetermined polarization characteristic, for example, P polarized light (parallel polarized light: P is the abbreviation of Parallel). The image light of the P polarized light directly passes through the beam splitter 101 upwards and travels toward the retro-reflective component 2 on the optical axis C2 corresponding to the optical axis C1. The beam splitter 101 has the property of allowing the P polarized light to pass through and reflecting the S polarized light (vertical polarized light: S is the abbreviation of Senkrecht). The beam splitter 101 is configured to form an angle of, for example, about 45 degrees with the image light of the P polarized light (optical axis C1, Z direction). That is, the beam splitter 101 is configured so that the main surface forms an angle of about 45 degrees with respect to the Y direction of the main surface of the liquid crystal display panel 11 and the retro-reflective component 2.

[0096] On the other hand, the λ / 4 plate 21 is disposed on the light incident surface of the retroreflective component 2. The image light of the P polarized light on the optical axis C2 emitted from the image display device 1 and transmitted from the beam splitter 101 passes through the λ / 4 plate 21 twice in total before and after being reflected by the retroreflective component 2, thereby being polarized and converted from the P polarized light to the S polarized light. As a result, the image light of the S polarized light traveling on the optical axis C2 after being reflected by the retroreflective component 2 is reflected by the beam splitter 101 and travels on the optical axis C3 in the Y direction. As shown in the figure, the image light of the S polarized light generates and displays a spatial floating image 3 as a real image at a predetermined position near the front side in the Y direction.

[0097] The predetermined position for forming the spatial suspended image 3 is determined based on the optical distance of the optical path of the optical system including the image display device 1, the beam splitter 101 and the polarized light separation component 2. In the present embodiment, the formation position of the spatial suspended image 3 is located near the near-front end of the area of ​​the main surface of the retro-reflective component 2 in the depth direction (Y direction). The predetermined position can be adjusted by design. As described above, in the present embodiment, the spatial suspended image 3 is generated by image light of linearly polarized light (S polarized light in the present embodiment). The user (the observer observing the spatial suspended image 3) can appropriately visually recognize the spatial suspended image 3 from the near-front side in the Y direction (i.e., the direction F indicated by the arrow).

[0098] In the above embodiment, the image display device 1, the beam splitter 101 and the retro-reflective component 2 can be maintained as follows: Figure 8 The Z-shaped positional relationship shown in the figure provides the user (observer) with a well-visible spatial floating image 3. The spatial floating image display device of the above-mentioned embodiment can be suitably used in a state of being arranged on a horizontal surface such as a desk, table, shelf, etc.

[0099] In addition, if Figure 8As shown, when the beam splitter 101 is arranged to form an angle of about 45 degrees with respect to the image light of the P polarized light (optical axis C1, Z direction), the image displayed on the image display device 1, that is, the liquid crystal display panel 11, is generated and displayed as a spatial floating image 3 while maintaining its aspect ratio. More specifically, when a perfect circle is displayed on the liquid crystal display panel 11, a perfect circle is also displayed as the spatial floating image 3.

[0100] [Second embodiment]

[0101] Here, when the spatial floating image display device of the first embodiment is used, when the spatial floating image display unit 400 is viewed from the user's (observer's) viewpoint in the Y direction (horizontal direction), that is, from Figure 8 In the direction F, the beam splitter 101 looks like a semi-transparent plate. Therefore, the user can visually recognize the situation on the inner side of the beam splitter 101 (the opposite side of the beam splitter 101 from the user's point of view) to a certain extent while observing the spatial suspended image 3. This means that, on the contrary, from the inner side of the beam splitter 101, that is, from the opposite side of the beam splitter 101 from the user's point of view, that is, Figure 8 The user can also visually recognize the situation on the user side to some extent through the beam splitter 101 in the direction G. However, the spatial floating image 3 itself as a real image cannot be visually recognized from the direction G.

[0102] As described above, the beam splitter 101 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 on a flat glass substrate. Therefore, when image light (here, P polarized image light emitted from the liquid crystal display panel 11 constituting the image display device 1) is irradiated onto the surface of the beam splitter 101, most of the light is transmitted through the beam splitter 101, while at least a portion of the light irradiated onto the beam splitter 101 is visually recognized as reflected light on the beam splitter 101.

[0103] That is, in Figure 8 In the embodiment, when the image light on the optical axis C1 emitted from the image display device 1 is irradiated to the beam splitter 101, most of the image light (approximately more than 90%) is transmitted through the beam splitter 101 and reaches the retroreflective sheet 2, while a part of the image light (approximately about 5% to 10%) is reflected by the beam splitter 101. The reflected light is represented as reflected image light R.

[0104] In other words, Figure 8 In the example, if the spatial floating image display unit 400 is observed from a direction G opposite to the original user's viewpoint F, the image light reflected on the beam splitter 101 may be seen ( Figure 8The reflected image light R can be more prominently visually recognized when the brightness around the spatial floating image display unit 400 is low, that is, when the room is dark.

[0105] The following describes the solution to this problem, namely Figure 8 A method for making the reflected image light R invisible in the direction G or reducing the brightness of the reflected image light R.

[0106] Fig. 9 , Fig.10 In order to solve the above problems, Figure 7 , Figure 8 The illustrated spatial floating image display unit 400 is deformed into a more vertically elongated embodiment, and is a three-dimensional view showing the appearance of the spatial floating image display device when viewed from the upper side (diagonally above). Fig. 9 The height ratio of the device in the Z direction is Figure 7 The overall height of the device in the Z direction is large. Fig.10 The angle B2 of the inclined surface of the beam splitter 101 is configured to be greater than Figure 8 The angle B1 (about 45 degrees) is large. Figure 7 Similarly, it is a surface corresponding to the direction F in which the user can visually recognize the space floating image 3 (indicated by a dotted frame) formed by the space floating image display unit 400 from the substantially front. Fig. 9 In the figure, the Z direction is the vertical direction, the X direction and the Y direction are two horizontal directions, the X direction is the left-right direction (the horizontal direction in the screen of the spatial floating image 3), and the Y direction is the depth direction and the front-back direction (the direction in which the user views the spatial floating image 3).

[0107] exist Fig. 9 In, with Figure 7 Similarly, on the upper side of the housing 106, i.e., the image display device section 300, the beam splitter 101 is arranged via the frame 108 as a support so as to form an inclined surface relative to the XY plane (horizontal plane). In addition, the retro-reflective component 2 and the λ / 4 plate 21 are arranged on the XY plane via the frame 108 as a support relative to the beam splitter 101. Here, two sides or three sides of the rectangle of each of the beam splitter 101 and the retro-reflective component 2 are adhered and fixed to the frame 108 as a corresponding support. Moreover, as shown in the figure, relative to a predetermined position of the near front side of the beam splitter 101 in the Y direction, the upper part of the space floating image 3 is formed to be slightly inclined toward the near front side of the user. That is, in the Z direction, the upper part of the space floating image 3 is formed to be inclined from the lower part of the space floating image 3 toward the user side. As shown in the figure, the two sides of the space floating image 3 extending in the Z direction are inclined at a predetermined angle γ relative to the Z direction (vertical direction).

[0108] Fig.10 From the side, i.e. the X-axis direction, Fig. 9 Observe the direction H Fig. 9 Schematic diagram of the space suspended image display device shown in FIG. Fig.10 In the figure, the above-mentioned direction F is also set as the negative direction of the Y direction, and the direction F' is shown as the inclined direction when the space floating image 3 formed slightly inclined is visually recognized from the front (vertical direction of the surface).

[0109] exist Fig.10 In the embodiment, the image light emitted from the liquid crystal display panel 11 is generally linearly polarized light (S polarized light or P polarized light). Fig.10 In the embodiment of the present invention, the image light emitted from the liquid crystal display panel 11 is P-polarized image light. In this embodiment, in order to allow the above-mentioned image light to pass through the beam splitter 101, when the image light emitted from the liquid crystal display panel 11 is P-polarized light, it can be directly emitted to the beam splitter 101. On the other hand, when the image light emitted from the liquid crystal display panel 11 is S-polarized light, in order to convert the S-polarized image light into P-polarized light, it is made to pass through the λ / 2 plate 14 ( Fig.14 ).

[0110] Fig.14 The following is an example of the configuration of the λ / 2 plate 14 in an embodiment (a variation of the second embodiment) in which the image light emitted from the liquid crystal display panel 11 is S-polarized light. The λ / 2 plate 14 is a different element from the λ / 4 plate 21 of the retroreflective component 2, and is a polarization conversion element, a phase difference plate, and a half-wave plate that converts S-polarized light into P-polarized light. Here, the liquid crystal display panel 11 and the λ / 2 plate 14 are configured together with the light source device 13 and the absorption-type polarizing plate 12 in the housing 106 at a position such as shown in the figure. Fig.14 In the figure, on the image light emitting surface of the liquid crystal display panel 11, a λ / 2 plate 14 is provided in contact with the upper side in the Z direction, and an absorbing polarizing plate 12 is provided in contact with the upper side thereof.

[0111] Not limited to Fig.14 As another structural example, a λ / 2 plate 14 may be provided on the lower surface of a transparent member in the opening 1061 of the housing 106 .

[0112] exist Fig.10 The original image light of the P polarized light from the liquid crystal display panel 11, or Fig.14 The image light (P polarized light image light) converted into P polarized light by the λ / 2 plate 14 is Fig.10The image light incident on the retroreflective component 2 passes through the λ / 4 plate 21 and is incident on the retroreflective component 2. At this time, the image light incident on the retroreflective component 2 passes through the λ / 4 plate 21 twice when incident on the retroreflective component 2 and when reflected, so it is converted into S-polarized image light. The image light reflected by the retroreflective component 2 is converted into S-polarized image light as described above, so it is reflected by the beam splitter 101. As a result, Fig.10 The position shown generates a spatial suspended image 3.

[0113] At this time, Fig.10 In the figure, when the original image light of P polarized light from the liquid crystal display panel 11 or the image light converted into P polarized light by the above-mentioned λ / 2 plate 14 is incident on the beam splitter 101, the proportion (reflectivity) of reflection on the beam splitter 101 is different depending on the incident angle α to the beam splitter 101.

[0114] Fig.11 The graph shown is a graph showing the incident angle and the reflectance (%R) of the glass surface when S-polarized light and P-polarized light are incident from air on glass having a refractive index of n=1.5. Fig.11 In FIG. 1 , the dotted curve represents the change in reflectivity with respect to the change in the incident angle of the image light of the S polarized light, and the solid curve represents the change in reflectivity with respect to the change in the incident angle of the image light of the P polarized light. Fig.11 As shown in FIG. 1 , in the image light of S polarized light, the reflectivity increases monotonically as the incident angle increases. In contrast, in the image light of P polarized light, the reflectivity approaches 0 as the incident angle increases, and the reflectivity becomes 0 at a certain angle. When the incident angle increases further, the reflectivity increases again. In addition, if the incident angle is the same, the reflectivity of the image light of S polarized light is always greater than the reflectivity of the image light of P polarized light.

[0115] like Fig.11 As shown in FIG. 1 , the incident angle at which the reflectance is 0 in the P-polarized image light is called the Brewster angle (denoted as θB). The Brewster angle θB is determined by the following formula 1 based on the refractive indexes of two materials (here, air and glass).

[0116] θB=arctan(n2 / n1)( 式1 )

[0117] In Formula 1, n1 is the refractive index of the incident side (ie, air), and n2 is the refractive index of the transmission side (ie, glass). For example, the Brewster angle θB of light incident from air with a refractive index of 1 to glass with a refractive index of 1.5 is 56.3 degrees.

[0118] from Fig.11It can be seen that in the image light of S polarized light, reflection continues to occur even if the incident angle changes, and in the image light of P polarized light, when the incident angle becomes Brewster angle θB, it enters the material (glass) without being reflected. That is, it has the property that the reflectivity (%R) is 0 at Brewster angle θB. On the other hand, according to formula 1, it can be seen that the Brewster angle changes according to the refractive index of the incident material, and the larger the refractive index of the transmission side relative to the incident side, the larger the Brewster angle.

[0119] As described above, when the image light of P polarized light is incident on the beam splitter 101 at the Brewster angle calculated by Formula 1 based on the refractive index (n2) on the transmission side corresponding to the material of the beam splitter 101, it is not reflected on the beam splitter 101. In addition, as described above, the beam splitter 101 is formed as an optical thin film on a flat glass, for example, and therefore the Brewster angle θB of the beam splitter 101 becomes the same value (56.3 degrees) as the Brewster angle θB of glass (more specifically, quartz glass).

[0120] As a result, Fig.10 In the embodiment, if the image light of P polarized light emitted from the image display device 1 based on the image light from the liquid crystal display panel 11 is incident on the beam splitter 101 at the Brewster angle θB, the reflected image light R reflected on the beam splitter 101 is substantially 0. It is not possible to reflect the image light from the direction opposite to the direction in which the spatial floating image 3 is formed, specifically, from Fig.10 The reflected image light R is visually recognized in the direction L. Thus, the image light that may be troublesome to others other than the user of the spatial floating image display device can be difficult to be seen by others, and on the other hand, the image light that the user does not want to be seen by others can be prevented from being seen by others.

[0121] In addition, according to Fig.11 As shown in the graph, even if the incident angle α of the image light to the beam splitter 101 is only set to the Brewster angle θB (56.3 degrees), or a slightly smaller angle close to the Brewster angle θB (for example, an angle in the range from 50 degrees to less than 56.3 degrees) (50 degrees ≤ α < θB), even if the reflected image light R cannot be completely reduced to 0, the reflectivity of the image light in the beam splitter 101 is less than 2%, and the reflected image light R can be reduced to a level that is almost unrecognizable. In addition, even if the incident angle α to the beam splitter 101 is an angle far from the Brewster angle θB (for example, α < 50 degrees), according to Fig.11 As shown in the graph, the brightness of the reflected image light R can be reduced simply by converting the image light incident on the beam splitter 101 from S-polarized light to P-polarized light using, for example, the λ / 2 plate 14 .

[0122] As described above, the image light emitted from the image display device 1 is configured so that the incident angle α when it is incident on the optical axis C1 to the beam splitter 101 is Brewster angle θB (specifically, 56.3 degrees) or an angle within a range close to Brewster angle θB (50 degrees ≤ α < θB). Fig.10 As shown in FIG. 1 , the angle of arrangement of each component is specified. Fig.10 This is an example of α=θB. In particular, the configuration angle of the inclined surface of the beam splitter 101 is angle β (β=90 degrees - θB=33.7 degrees) with respect to the Z direction (vertical direction) and angle B2 (B2=θB=56.3 degrees) with respect to the horizontal plane (Y direction).

[0123] Thus, the reflected image light R of the image light in the beam splitter 101 can be reduced to zero or close to zero, to a level that does not pose a problem in practical use. That is, when the beam splitter 101 is viewed from the opposite side (direction L) to the side where the spatial floating image 3 can be visually recognized, the reflected image light R can be reduced to a level that cannot be visually recognized.

[0124] The specific incident angle α when incident on the beam splitter 101 is not limited to the Brewster angle θB described above, and effects similar to those of the above-described embodiment can be obtained as long as the angle is set within a range of 45 to 60 degrees.

[0125] [Modification (Third Embodiment)]

[0126] Here, when the incident angle with respect to the beam splitter 101 is set to the Brewster angle, a new problem described below also arises. Figure 8 As shown, in the case of a structure in which the beam splitter 101 is configured at approximately 45 degrees relative to the image light of the P polarized light (optical axis C1, Z direction), the image displayed on the image display device 1, i.e., the liquid crystal display panel 11, maintains its aspect ratio, and a spatial floating image 3 is generated and displayed in the direction F corresponding to the horizontal direction (Y direction), which is the direction of the user's assumed line of sight.

[0127] On the other hand, Fig.10 As shown, in a structure where the incident angle α of the P-polarized image light to the beam splitter 101 is the Brewster angle θB, i.e., 56.3 degrees, when viewed from the user (direction F), a spatial floating image 3 is generated in a direction obliquely downward (a direction corresponding to direction F'). Fig.10 As shown in the figure, the image light of S polarized light from the beam splitter 101 is reflected on the optical axis C3 having an angle corresponding to (θB×2) with respect to the vertical direction (Z direction). Therefore, the surface of the spatial floating image 3 is configured as a plane perpendicular to the direction of the optical axis C3, and is configured as an inclined surface with a predetermined angle γ (an angle determined in relation to θB and β) with respect to the XZ plane, and the upper side is inclined downward.

[0128] In the case of this configuration, when the user views the spatial floating image 3 from the direction F, not only does visibility deteriorate, but a new problem also arises in that the spatial floating image 3 cannot be visually recognized depending on the position of the user's eyes.

[0129] therefore, Fig.12 , Fig.13 The following is an embodiment of a method for solving the above-mentioned problem of deterioration of visibility. Fig.12 In FIG. 1 , a three-dimensional diagram of the spatial floating image display device of this embodiment is also shown. Fig.12 In the embodiment, the housing 106 is deformed so that the spatial floating image 3 is aligned with the XZ plane. Specifically, the height of the front surface 106s1 in the housing 106 corresponding to the side where the spatial floating image 3 is formed is made smaller than Fig. 9 In the case of high, the height of the rear surface 106s2 corresponding to the opposite side of the side where the spatial floating image 3 is formed is made low. Fig. 9 In the example, the height of the housing 106 in the Z direction is 10 mm, the width in the X direction is 80 mm, and the depth in the Y direction is 30 mm. Fig.12 In FIG. 1 , the height of surface 106s1 is 26 mm, and the height of surface 106s2 is 6 mm. As a result, Fig.12 In the example, the height difference between the front and rear sides is 20 mm. On the other hand, the depth between the front and rear sides is also 30 mm. Fig.12 The spatial floating image display unit 400 is tilted backward as a whole at an angle of arctan (20 / 30), that is, 33.7 degrees. The 33.7 degrees is equivalent to the angle β of the difference between 90 degrees and 56.3 degrees, which is the Brewster angle θB. Alternatively, the angle formed by the light emitting surface of the liquid crystal display panel and the light incident surface of the retroreflective component 2 is equivalent to the angle of the difference between 90 degrees and the Brewster angle θB.

[0130] Fig.13 Representation and Fig.12 The corresponding cross-sectional view is viewed from direction H. Fig.12 , Fig.13 In the embodiment, the upper surface of the housing 106 having different heights at the front and rear sides is an inclined surface relative to the XY plane, and the upper side of the upper surface is inclined with respect to the XY plane. Fig. 9 , Fig.10The spatial floating image display unit 400 is arranged in the same positional relationship. When the light exit surface of the image display device 1 is arranged along the upper surface of the housing 106, the image display device 1 is arranged in a Z-shaped manner relative to the beam splitter 101 and the retro-reflective component 2 in the housing 106. That is, the light exit surface of the image display device 1 or the surface of the liquid crystal display panel is arranged in a tilted manner, or the distance between the light exit surface of the image display device 1 on the housing 106 side connected to the beam splitter 101 and the retro-reflective component 2 is shorter than the distance between the light exit surface of the image display device 1 on the housing 106 side not connected to the beam splitter 101 and the retro-reflective component 2. Alternatively, in the light exit surface of the image display device 1 or the light exit surface of the liquid crystal display panel, the distance between the side corresponding to the spatial floating image formed and the retro-reflective component 2 is shorter than the distance between the side opposite to the spatial floating image and the retro-reflective component 2.

[0131] Therefore, through Fig.12 The structure of the space floating image 3 is formed on the same plane as the XZ plane. Fig.12 When the direction M corresponds to the negative direction of the Y direction in the image, the spatial suspended image 3 becomes an image with better visual recognition when observed by the user, that is, high brightness, and the aspect ratio of the spatial suspended image 3 also has the original aspect ratio (the same aspect ratio as the image displayed on the liquid crystal display panel 11).

[0132] As described above, when the incident angle of the P-polarized image light displayed on the liquid crystal display panel 11 to the beam splitter 101 is the Brewster angle θB, that is, 56.3 degrees, Fig. 9 As shown in FIG. 1 , the space floating image 3 is generated diagonally downward, which deteriorates the visual recognition for the user. Fig.12 As shown, by making the front side of the housing 106 including the image display device 1 high and the rear side low, the plane forming the spatial floating image 3 can be made consistent with the XZ plane. This can optimize the visibility of the spatial floating image 3 and make it suitable for use.

[0133] [Effects, etc.]

[0134] As described above, according to the spatial floating image display device of each embodiment and modified example, it is possible to display a spatial floating image that is mainly suitable for indoor use and has high visual recognition. In addition, a spatial floating image display device can be provided, which makes the brightness of the reflected image light caused by the image light from the image display device 1 based on the image light from the liquid crystal display panel 11 reflected on the beam splitter 101 to be zero or the brightness is reduced. As a result, from the perspective of the user who is located at a position where the spatial floating image can be observed, the person on the opposite side of the spatial floating image display device cannot visually recognize the above-mentioned reflected image light. It brings about the effect that it is difficult for people other than the user to see unnecessary or troublesome image light in the room where the spatial floating image display device is installed.

[0135] In addition, in order to make the brightness of the above-mentioned reflected image light zero or reduce it, it is necessary to increase the incident angle of the image light relative to the beam splitter 101 from 45 degrees to the Brewster angle θB, that is, 56.3 degrees, which causes the problem that the spatial floating image is tilted downward from the user's point of view, thereby deteriorating the visual recognition. In response to this problem, by appropriately changing the height of the front side and the rear side of the housing 106 including the image display device 1, the surface forming the spatial floating image 3 can be set as a vertical surface, so that the visual recognition is optimized.

[0136] According to the above effects, the spatial floating image display device of each embodiment and modified example will not emit unnecessary image light for people other than the user even when used in a relatively narrow room, and can display a bright and visually recognisable spatial floating image. It is small and light, and is therefore suitable for being easily set up on a desk, table, shelf, etc. in the room.

[0137] In the technology involved in this embodiment, by displaying a spatially suspended image in a state where high-resolution and high-brightness image information is suspended in space, the spatially suspended image can also be used as a non-contact user interface, and the user can operate without feeling uneasy about contact infection of infectious diseases. This contributes to "3. Health and well-being for all individuals" of the Sustainable Development Goals (SDGs) advocated by the United Nations.

[0138] In addition, in the technology of this embodiment, by reducing the divergence angle of the emitted image light and then aligning it with a specific polarized wave (polarized light), only the regular reflected light is efficiently reflected relative to the retroreflective component, so the light utilization efficiency is high, and a bright and clear spatial floating image can be obtained. According to the technology of this embodiment, a non-contact user interface with excellent usability that can significantly reduce power consumption can be provided. This contributes to the "9. Building a foundation for industrial and technological innovation" of the Sustainable Development Goals (SDGs) advocated by the United Nations.

[0139] The embodiments of the present disclosure are described in detail above, but are not limited to the above embodiments, and various changes can be made without departing from the main purpose. In the absence of special limitations, each component can be single or multiple. Regarding the components of each embodiment, in addition to the necessary components, addition, deletion, replacement, etc. can be performed. It can also be a way to combine the embodiments.

[0140] Explanation of symbols

[0141] 1: image display device, 2: retro-reflective component, 3: spatially suspended image, 11: liquid crystal display panel, 12, 112: absorption-type polarizing plate, 13: light source device, 21: λ / 4 plate, 100: transparent component, 101: beam splitter (polarized light separation component), 106: shell, 108: frame, 300: image display device part, 400: spatially suspended image display part, 1061: opening part.

Claims

1. A spatial suspended image display device, which displays a spatial suspended image, characterized in that: The spatial floating image display device comprises: A housing containing an image display device; a retro-reflective component disposed outside the housing and facing the image display device, with a λ / 4 plate provided on the retro-reflective surface; and a polarized light separation component, which is disposed outside the housing in a space connecting the image display device and the retroreflective component at a predetermined angle relative to the image display device and the retroreflective component, The image display device comprises a light source device and a liquid crystal display panel as an image source. Image light of a specific polarized wave emitted from the liquid crystal display panel is incident on the polarized light separation component at a specific incident angle, passes through the polarized light separation component, is reflected by the retroreflective component, passes through the λ / 4 plate and is polarized to be transformed, thereby becoming image light of another polarized wave. The image light of the other polarized wave is reflected by the polarized light separation component, and based on the reflected image light, a spatially suspended image is displayed as a real image at a predetermined position.

2. The spatial floating image display device according to claim 1, characterized in that: The image light of specific polarization incident on the polarization separation component is P-polarized light.

3. The spatial floating image display device according to claim 1, characterized in that: The specific incident angle on the polarized light separation element is an angle within a range of not less than 45 degrees and not more than 60 degrees.

4. The spatial floating image display device according to claim 1, characterized in that: The specific incident angle to the polarized light separation component is a Brewster's angle corresponding to the material of the polarized light separation component, or an angle within a range from 50 degrees to less than the Brewster's angle.

5. The spatial floating image display device according to claim 4, characterized in that: The height of the front surface of the housing containing the image display device and corresponding to the side where the spatial floating image is formed is higher than the height of the rear surface, so that the surface displaying the formed spatial floating image becomes a vertical plane.

6. The spatial floating image display device according to claim 1, characterized in that: The polarized light separation member and the retroreflective member are supported by a frame on the housing in which the image display device is housed.

7. The spatial floating image display device according to claim 1, characterized in that: The reflective polarizing plate or the metal multilayer film reflecting a specific polarized wave of the polarized light separation member is formed on a glass substrate as an optical thin film.

8. The spatial floating image display device according to claim 1, characterized in that: The surface roughness of the retroreflective surface of the retroreflective member is set so that the ratio of the blur amount of the spatial floating image to the pixel size of the image display device is 40% or less. The light source device comprises: Point or surface light source; an optical element portion that reduces a divergence angle of light from the light source; a polarization conversion unit that makes the light from the light source consistent with polarization in a specific direction; as well as a light guide having a reflective surface for transmitting light from the light source to the liquid crystal display panel, An image beam of image light from the liquid crystal display panel is controlled according to the shape and surface roughness of the reflective surface.

9. The spatial floating image display device according to claim 2, characterized in that: The image light from the liquid crystal display panel is S polarized light. The spatial floating image display device includes a λ / 2 plate that converts the S-polarized image light from the liquid crystal display panel into the P-polarized light to be incident on the polarized light separation component.

Images