Display device

Abstract

To provide a display device which allows an aerial picture to be seen three-dimensionally.SOLUTION: A display device 100 of the present invention includes: a light source (an LED light) 110; a retroreflective member 120; an optical member 130 including one of a beam splitter and a half mirror; and a three-dimensional structure 140 having an optical performance of one of light guide and scattering. When the three-dimensional structure 140 is irradiated with light L from the light source 110, an aerial picture 140A of the three-dimensional structure 140 is displayed. The three-dimensional structure 140 includes an upper surface 142 and a side surface 144 and a taper is provided in the side surface 144.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a display device that displays an image in the air by utilizing retroreflection, and in particular to stereoscopic visualization of the aerial image. [Background technology]

[0002] Aerial imaging by retro-reflection (AIRR) is known. For example, Patent Document 1 discloses a display device using two retro-reflection members to enable an image formed in the air to be observed from a wider angle. Patent Document 2 discloses an aerial image display system having a half mirror and a reflecting member selected from the group consisting of a concave mirror, a Fresnel mirror, and a retro-reflection member, the reflecting member having a reflective polarizer, and the reflective polarizer forming the reflecting surface of the reflecting member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-107165 A [Patent Document 2] International Publication No. WO2022 / 138157 Summary of the Invention [Problem to be solved by the invention]

[0004] Most of the conventional aerial imaging technologies use a display as a light source, and even if an image on a display is projected into the air, the aerial image itself is viewed as a flat image. FIG. 1 is a diagram showing an example of the configuration of a conventional display device for aerial images using retroreflection. The display device 10 is configured to include a display 20 including a liquid crystal panel or the like, a retroreflection member 30, and a beam splitter (or half mirror) 40. When the display 20 displays an original image P1, the original image P1 emitted from the display 20 is reflected by the beam splitter 40 toward the retroreflection member 30, and the light reflected by the retroreflection member 30 passes through the beam splitter 40 to form an aerial image P2, which is then displayed in the line of sight of the user U.

[0005] There is a technology that uses an optical illusion to make flat images appear three-dimensional by detecting the camera's line of sight and changing the flat image according to the angle of the line of sight. However, if this technology does not detect the line of sight 100% perfectly, there will be a delay in tracking the image changes, creating a sense of discomfort. In addition, line of sight detection can basically only be performed by one person in front of the camera, which means that multiple people cannot view a three-dimensional image at the same time. In particular, when using aerial images as a user interface (UI), it is preferable for the target (aerial image) to have a physically three-dimensional structure rather than a flat surface.

[0006] An object of the present invention is to provide a display device that solves these conventional problems and realizes stereoscopic viewing of aerial images. [Means for solving the problem]

[0007] The display device of the present invention is capable of displaying an aerial image by utilizing retroreflection, and includes a light source, a three-dimensional structure having at least one of the optical properties of light guiding and scattering and illuminated by the light source, a retroreflective member that reflects the three-dimensional structure, and an optical member that transmits the reflected light of the retroreflective member to form an aerial image of the three-dimensional structure, and the three-dimensional structure includes at least an upper surface and a side surface connected to the upper surface, and at least some of the side surfaces are tapered.

[0008] In one embodiment, a space is formed behind the tapered side and top surface. In one embodiment, unevenness is formed in the height direction of the three-dimensional structure. In one embodiment, the three-dimensional structure further includes processing that causes a change in light transmission or diffusion at an edge where the top surface and the side surface intersect, or an edge where the side surfaces intersect. In one embodiment, the processing includes edge roughening processing. In one embodiment, the processing includes coating or addition of another material. Effect of the Invention

[0009] According to the present invention, by providing a taper on the side of the three-dimensional structure, the brightness of the tapered part and the other parts changes depending on the viewing position and angle, and aerial images of the three-dimensional structure can be made to have a clearer stereoscopic view. Furthermore, by processing the edges of the three-dimensional structure to cause a change in transmission or diffusion, the edges of the aerial images can be made clearer, enhancing the three-dimensional effect of the aerial images. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing a configuration example of a conventional display device that uses retroreflection. [Diagram 2] 1A and 1B are diagrams illustrating the optical properties of a retroreflective member. [Diagram 3] FIG. 1 is a diagram showing a configuration of a display device according to an embodiment of the present invention. [Figure 4] 4A and 4B are diagrams showing a three-dimensional structure according to a first embodiment of the present invention, in which FIG. 4A is a perspective view seen from the front side, FIG. 4B is a perspective view seen from the back side, and FIG. 4C is an enlarged view of a cross section taken along line AA in FIG. 4A. [Diagram 5] FIG. 2 is a diagram illustrating an aerial image of a three-dimensional structure according to the first embodiment of the present invention. [Figure 6] 6A and 6B are diagrams showing a three-dimensional structure according to a second embodiment of the present invention, in which FIG. 6A is a perspective view seen from the front side, and FIGS. 6B and 6C are enlarged views of a cross section taken along line BB in FIG. 6A. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Next, an embodiment of the present invention will be described. The display device of the present invention displays a three-dimensional floating image using retroreflection without the need for special glasses or the like. The display device of the present invention can be applied to a user input interface using floating images. It should be noted that the drawings referred to in the following description of the embodiments include exaggerated representations to facilitate understanding of the invention, and do not directly represent the shape and scale of the actual product. EXAMPLES

[0012] Next, an embodiment of the present invention will be described in detail with reference to the drawings. In the technology for generating aerial images (AIRR method), the use of a retroreflector is essential. A retroreflector is an optical member that reflects light in the same direction as the incident light, and is composed of, for example, a triangular pyramid retroreflector, a full cube corner retroreflector, or a prism retroreflector, or a bead retroreflector.

[0013] FIG. 2 shows a cross section of a triangular pyramidal retroreflective element and a relationship between incident light and reflected light. The reflective surfaces S1 and S2 of the triangular pyramidal retroreflective element 50 are perpendicular to each other, and the incident light L1 incident on the reflective surface S1 at an incident angle (π / 2-θ) is reflected by the reflective surfaces S1 and S2, and the reflection angle of the reflected light L2 when reflected by the reflective surface S2 is equal to the incident angle (π / 2-θ). Therefore, the reflected light L2 is reflected in the same direction as the incident light L2. However, due to the structure of the retroreflective member, a shift occurs in the positions of the incident light L1 and the reflected light L2, and this shift deteriorates the clarity or resolution of the aerial image, thereby reducing the visibility of the aerial image.

[0014] When displaying an aerial image using retroreflection, it is possible to make the aerial image three-dimensional by making the original image three-dimensional. However, as described above, if the resolution of the aerial image deteriorates due to structural reasons of the retroreflective member, it is difficult to visually recognize a clear aerial image with a three-dimensional feel just by making the original image three-dimensional. In particular, if the edges of the aerial image become unclear, the edges become dull, or the aerial image lacks a sense of depth, the aerial image will not appear three-dimensional to the user. In view of these points, the display device of this embodiment makes it possible to display a clear aerial image with a three-dimensional feel.

[0015] 3 is a diagram showing an example of the configuration of a display device according to an embodiment of the present invention. As shown in the figure, the display device 100 of this embodiment includes a light source 110, a retroreflective member 120, an optical member 130 including a beam splitter or a half mirror, and a three-dimensional structure 140.

[0016] The light source 110 is not particularly limited in configuration as long as it can illuminate the three-dimensional structure 140, and may be, for example, an LED light in which a plurality of LEDs are arranged two-dimensionally. The light output from the light source 110 may have any wavelength, and may emit white light, for example. The light source 110 may also emit polarized light as necessary, and a light-emitting element or a polarizing filter may be used for this purpose.

[0017] The retroreflective member 120 is an optical member that reflects light in the same direction as the incident light, and its configuration is not particularly limited, but it may be composed of triangular pyramid retroreflective elements as shown in Fig. 2, or may be composed of prism-type retroreflective elements such as full cube corner-type retroreflective elements, or bead-type retroreflective elements. The retroreflective member 120 may also include a retardation film such as a λ / 4 plate on its reflective surface.

[0018] The optical member 130 is composed of a beam splitter or a half mirror, and has the function of transmitting a part of the incident light and reflecting a part of it. A part of the light of the three-dimensional structure 140 irradiated by the light source 110 is reflected by the optical member 130, and the reflected light is incident on the retroreflective member 120, and a part of the light reflected in the same direction as the incident light is transmitted through the optical member 130, and an aerial image 140A is formed. The aerial image 140A is formed at a position that is plane-symmetrical to the three-dimensional structure 140 with respect to the optical member 130.

[0019] The three-dimensional structure 140 is made of a light-transmitting material, such as glass, acrylic plastic, polycarbonate resin, or cycloolefin resin, and has optical properties of guiding light, scattering light, or both. The three-dimensional shape and size of the three-dimensional structure 140 are not particularly limited, and the three-dimensional structure 140 has a three-dimensional shape to be displayed as an aerial image. For example, the three-dimensional structure 140 can have various three-dimensional shapes such as letters, figures, symbols, and figures. Here, the three-dimensional structure 140 has the three-dimensional shape of the alphabet "N."

[0020] The three-dimensional structure 140 is illuminated by light from the light source (LED unit) 110, and the illuminated light is guided into the transparent material of the three-dimensional structure 140 or scattered on the surface of the transparent material, so that the three-dimensional structure 140 exists as if it were a three-dimensional light source "N."

[0021] FIG. 4 is a diagram showing details of a three-dimensional structure according to a first embodiment, in which FIG. 4(A) is a perspective view of a three-dimensional structure 140 seen from the front side, FIG. 4(B) is a perspective view of the three-dimensional structure 140 seen from the back side, and FIG. 4(C) is an enlarged view of a cross section taken along line AA in FIG. 4(A). In one embodiment, the three-dimensional structure 140 is formed by processing a thin plate-like transparent member having a certain thickness into the shape of an "N". The upper surface 142 of the three-dimensional structure 140 represents the planar shape of an "N", and a side surface 144 extending from the upper surface 142 toward the bottom is tapered. In other words, the intersection angle between the upper surface 142 and the side surface 144 is an obtuse angle, and the three-dimensional structure 140 has a depth that expands from the upper surface 142 toward the bottom as shown in FIG. 4(C), and a trapezoidal cavity or space 146 is formed behind the upper surface 142 and the side surface 144. The taper angle is appropriately selected depending on the three-dimensional shape of the three-dimensional structure 140.

[0022] 5 is a diagram for explaining an aerial image of a three-dimensional structure, and shows a schematic representation of an aerial image of a portion of the three-dimensional structure. As described above, three-dimensional structure 140 includes upper surface 142, tapered side surface 144, and space 146, and when three-dimensional structure 140 is illuminated by light source (LED light) 110, aerial image 140A of three-dimensional structure 140 is displayed. The attachment position and attachment direction of three-dimensional structure 140 are arbitrary, but for example, three-dimensional structure 140 is positioned so that upper surface 142 of aerial image 140A is directed toward the line of sight of user U.

[0023] As shown in the figure, the appearance of the three-dimensional structure 140 changes depending on the viewing direction U1, U2 of the user U. In the viewing direction U1, the thickness L1 of the transparent member increases due to the taper of the side surface 144, making it difficult to guide light in that area, resulting in a dark appearance. On the other hand, in the viewing direction U2 where the side surface 144 does not exist, the thickness L2 of the transparent member decreases due to the space 146 on the back side, making it easier to guide light in that area, resulting in a bright appearance. In other words, the degree of light guiding changes depending on the user's viewing position and angle, so the appearance (brightness) changes and the aerial image of the three-dimensional structure can be viewed more three-dimensionally.

[0024] Thus, according to this embodiment, by providing a taper or unevenness in the height direction of the three-dimensional structure, the brightness changes depending on the degree of light guiding of the three-dimensional structure in the user's line of sight, and as a result, a clear aerial image with a three-dimensional feel can be viewed.

[0025] In the above embodiment, the top surface 142, the tapered side surface 144, and the space 146 on the back side of the three-dimensional structure 140 were formed by bending a thin transparent member, but this is just one example, and other methods may also be used, for example, to cut the side surface of a transparent member having a certain thickness to form a taper, and to form a recess or depression on the back side to form the space 146, or the three-dimensional structure may be molded into the vehicle model using an injection molding mold.

[0026] In the above embodiment, all the side surfaces 144 of the three-dimensional structure 140 are tapered, but this is merely an example and is not necessarily limited to this. For example, in the three-dimensional structure 140, a taper or space may be formed only on the side surfaces of the portion where the three-dimensional effect is to be emphasized.

[0027] Next, a second embodiment of the present invention will be described. In the second embodiment, a process is applied to the edge of a three-dimensional structure 140 to change the light transmission or diffusion. Figure 6 shows a three-dimensional structure according to the second embodiment, where Figure 6(A) is a perspective view of the three-dimensional structure seen from the front side, and Figures 6(B) and 6(C) are enlarged views of the cross section taken along line BB in Figure 6(A).

[0028] In the second embodiment, an edge 210 where the top surface 142 and the side surface 144 of the three-dimensional structure 200 intersect, or an edge 220 on the bottom side of the side surface 144, is processed to change the light transmission or diffusion. For example, as shown in FIG. 6B, the edges 210 and 220 are coated with a black material (PLA: polylactic acid). The black material is, for example, about 1 mm wide and 0.5 mm thick. By adding black paint, the edges 210 and 220 of the three-dimensional structure 200 have weaker light guide and the contrast with other parts is increased. This relatively emphasizes the edges 210 and 220, and the three-dimensional effect of the aerial image can be enhanced. The color of the material to be coated is not necessarily limited to black, and the width and thickness of the coating are not particularly limited. In short, the color and size of the material to be applied need only cause a change in the transmission or light guidance, and in addition to applying a material, a different material that causes a change in the transmission or light guidance may be attached.

[0029] As another embodiment, the edge processing may be performed by roughening the surfaces of the edges 210A, 220B, as shown in Fig. 6(C), for example. This causes light diffusion or scattering at the edges 210A, 220A, increasing the contrast between the edges 210A, 220A and other parts, and emphasizing the edges 210A, 220A in the aerial image. When performing the roughening process, for example, the edges 210A, 220B may be chamfered and the chamfered surfaces may be roughened.

[0030] Thus, according to this embodiment, by applying edge processing to the edges of the three-dimensional structure that creates a change in light transmission or diffusion, the edges of the three-dimensional structure are emphasized, thereby making it possible to display a clear aerial image with a three-dimensional feel.

[0031] In the above embodiment, the edges 210 and 220 of the three-dimensional structure 200 are processed, but the location and number of edges to be processed are arbitrary, and for example, the edges are processed on edges where it is desired to emphasize the three-dimensional effect. For example, in addition to the edges where the top surface and the side surface intersect, the edges where the side surfaces intersect may also be processed.

[0032] In the above embodiment, the letter "N" is displayed as the three-dimensional structure, but this is only an example, and the three-dimensional structure may be a three-dimensional representation of numbers, symbols, figures, characters, etc. other than letters. For example, the three-dimensional structure is determined according to an aerial image required in the user interface. In addition, the display device of this embodiment can be applied to user input, for example, computer devices, in-vehicle electronic devices, ATMs at banks, ticket purchasing machines at stations, elevator input buttons, etc.

[0033] Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and changes are possible within the scope of the gist of the invention described in the claims. [Explanation of symbols]

[0034] 100: Display device 110: Light source 120: Retroreflective member 130: Beam splitter 140: Three-dimensional structure 140A: Aerial image 142:Top 144:Side 146: Space 200: Three-dimensional structure 210, 220: Edge

Claims

1. A display device capable of displaying an aerial image using retroreflection, A light source; A three-dimensional structure having at least one optical property of light guiding and scattering and illuminated by the light source; A retroreflective member that reflects the three-dimensional structure; and an optical member that transmits the reflected light of the retroreflective member to form an aerial image of the three-dimensional structure, The three-dimensional structure includes at least an upper surface and a side surface connected to the upper surface, and at least a portion of the side surface is tapered.

2. The display device according to claim 1 , wherein a space is formed behind the side and top surface on which the tapered portion is provided.

3. The display device according to claim 1 , wherein the three-dimensional structure has projections and recesses formed in a height direction.

4. The display device according to claim 1 , wherein the three-dimensional structure further includes a treatment that causes a change in light transmission or diffusion at an edge where the top surface and the side surface intersect, or at an edge where the side surfaces intersect.

5. The display device of claim 4 , wherein the processing includes edge roughening.

6. The display device of claim 4 , wherein the processing includes applying or adding another material.

Images