Display device

Abstract

To provide a display device which can widen the angle of field of aerial pictures and reduce cost.SOLUTION: An aerial picture display device 100 according to the present invention includes: a display light source 110 with an emission surface for emitting pictures; a retroreflection material 120A arranged to be inclined to the outside at an inclination angle θA on one end part side of the display light source 110; a retroreflection material 120B arranged to be inclined to the outside at an inclination angle θB on another end part side; a beam splitter 130B arranged to face the retroreflection material 120A; and a beam splitter 130A facing the retroreflection material 120B. The display device displays aerial pictures PA and PB of the same content in two directions.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a display device having a function of displaying an image in the air using retroreflection.

Background Art

[0002] Aerial Imaging by Retro-Reflection (AIRR) is known. For example, the display device of Patent Document 1 includes a first retroreflective portion disposed at a position in the emission direction of light emitted from a light source, and reflects at least a part of the light transmitted through the first retroreflective portion as first reflected light, and allows at least a part of the first reflected light retroreflected by the first retroreflective portion to pass through, enabling observation of an aerial image from a wide angle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Due to reasons such as improved operability of non-contact devices and improved spatial design, AIRR-type display devices have attracted attention. In such cases, users do not necessarily view the aerial image from the front, and may view it from the side depending on the situation, and a display device with a wide viewing angle is required. FIGS. 1(A) and (B) are diagrams showing a schematic configuration of a conventional wide-viewing-angle display device. In the figures, solid lines indicate incident light, and broken lines indicate retroreflected light.

[0005] The display device 10 shown in Fig. 1(A) includes a display light source 20, a beam splitter 30, and a retroreflective material 40. By tilting the beam splitter 30 with respect to the retroreflective material 40, a wide viewing angle of the aerial image is realized. The incident light emitted from the display light source 20 is partially reflected by the beam splitter 30. The reflected light is reflected by the retroreflective material 40 in the same direction as the incident light. The retroreflected light passes through the beam splitter 30, and the aerial image P is displayed. The aerial image P is formed at a position symmetric to the display light source 20 with respect to the plane of the beam splitter 30. The users U1 and U2 can visually recognize the aerial image P within the range of the viewing angle θ at which they can observe the retroreflective material 40.

[0006] The display device 50 shown in Fig. 1(B) arranges two optical systems with reduced sizes of the optical system shown in Fig. 1(A). That is, it includes a pair of display light sources 60A and 60B, a pair of beam splitters 70A and 70B, and a pair of retroreflective materials 80A and 80B. By the display light sources 60A and 60B emitting images of the same content, the users U1 and U2 can simultaneously visually recognize the same aerial images PA and PB, and in fact, a wide viewing angle of the aerial image is realized.

[0007] However, the display device 10 shown in Fig. 1(A) can increase the viewing angle of the aerial image and can be viewed from the side. On the other hand, there are problems that the size of the optical system becomes large and it is difficult to view from the side depending on the video content. Also, the display device 50 shown in Fig. 1(B) has a problem that since it arranges a plurality of optical systems with a narrow viewing angle, the number of necessary components increases and the cost becomes high.

[0008] An object of the present invention is to provide a display device that can solve such conventional problems and widen the viewing angle of an aerial image while reducing the cost.

Means for Solving the Problems

[0009] The display device of the present invention can display a virtual image using retroreflection, and includes a light source that emits an image from an emission surface, a first retroreflective material disposed on one end side of the light source so as to be inclined outward at a first inclination angle with respect to the normal line of the emission surface, a second retroreflective material disposed on the other end side of the light source so as to be inclined outward at a second inclination angle with respect to the normal line of the emission surface, a first optical member that separates incident light into reflected light and transmitted light, the first optical member disposed so as to face the first retroreflective material, a second optical member that separates incident light into reflected light and transmitted light, and the second optical member disposed so as to face the second retroreflective material.

[0010] In one aspect, the first optical member is disposed parallel to the first retroreflective material, and the second optical member is disposed parallel to the second retroreflective material. In one aspect, the first and second retroreflective materials are spherical or curved. In one aspect, the display device displays a first virtual image in the direction in which the retroreflective surface of the first retroreflective material faces, and displays a second virtual image in the direction in which the retroreflective surface of the second retroreflective material faces, and the first virtual image and the second virtual image are the same. In one aspect, the first and second optical members are a half mirror, a beam splitter, or a polarizing beam splitter. In one aspect, the display device is disposed in the vehicle interior space between the driver's seat and the passenger seat.

Advantages of the Invention

[0011] According to the present invention, the first and second retroreflective materials are disposed on both sides of the light source so as to be inclined outward, and the first and second optical members are disposed so as to face the first and second retroreflective materials, so that two virtual images with the same content can be displayed in different directions, and in fact, the viewing angle of the virtual image can be increased. In addition, since two virtual images are displayed using one light source, the number of components in the optical system can be reduced, and the cost of the display device can be reduced.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0013] The display device according to the present invention displays an aerial image or an aerial image using retroreflection in a three-dimensional space that can be visually recognized without wearing special glasses or the like. It should be noted that the drawings referred to in the following description of the embodiments include exaggerated displays for ease of understanding of the invention and do not represent the actual shape and scale of the product as it is.

Embodiment

[0014] Next, embodiments of the present invention will be described in detail. FIG. 2 is a diagram showing the configuration of a display device according to an embodiment of the present invention. FIG. 2(A) is a front view thereof, FIG. 2(B) is a perspective view thereof, and FIG. 2(C) is a top view thereof.

[0015] The display device 100 of this embodiment is configured to include a light source 110, a pair of retroreflective materials 120A and 120B, and a pair of beam splitters 130A and 130B. Although these members are not shown here, they can be attached to, for example, a housing or a casing.

[0016] The light source 110 is not particularly limited as long as it has a function of emitting an image or a picture. For example, it can be a display light source such as a liquid crystal display device, an organic EL display device, or a projection display device. The display light source has, for example, a rectangular emission surface and emits an image in the normal direction (optical axis direction) of the emission surface. Such a display light source is not particularly limited. For example, it may be the screen of a smartphone as shown in Fig. 2(A), or alternatively, it may be the screen of a mobile terminal, the screen of a personal computer, the screen of a projector, or the like.

[0017] The retroreflective materials 120A and 120B are optical members that reflect light in the same direction as the incident light. For example, they are composed of prism-type retroreflective elements such as triangular pyramid-type retroreflective elements and full cube corner-type retroreflective elements, or bead-type retroreflective elements. A set of the exemplified retroreflective materials 120A and 120B are each composed of a rectangular sheet or thin plate of equal size. However, the sizes of the retroreflective material 120A and the retroreflective material 120B may be different.

[0018] Specifically, one of the retroreflective materials 120A is arranged so that its end EA is close to and aligned with one end D1 of the light source 110 (or its emission surface), and the retroreflective surface of the retroreflective material 120A is inclined outward at an angle θA with respect to the normal (optical axis) of the emission surface (see Fig. 2(C)). The other retroreflective material 120B is arranged so that its end EB is close to and aligned with the other end D2 of the light source 110 (or its emission surface), and the retroreflective surface of the retroreflective material 120B is inclined outward at an angle θB with respect to the normal (optical axis) of the emission surface.

[0019] The tilt angles θA and θB are set so that most of the light emitted from the light source 110 does not directly enter the retroreflective materials 120A and 120B, and so as to correspond to the viewpoint positions of the users. Also, the sizes of the retroreflective surfaces of the retroreflective materials 120A and 120B are determined so that the light reflected by the beam splitters 130A and 130B can be sufficiently incident thereon. If the viewpoint positions of the left and right users are symmetric with respect to the display device 100, then θA = θB, and a set of retroreflective materials 120A and 120B can be arranged symmetrically with respect to the light source 110. Also, if the viewpoint positions of the left and right users are asymmetric or in different directions with respect to the display device 100, the tilt angle θA of the retroreflective material 120A and the tilt angle θB of the retroreflective material 120B can be set to different angles, respectively.

[0020] The beam splitters 130A and 130B are optical members that separate incident light into transmitted light and reflected light. For example, a half mirror or, when polarized light is used, a polarizing beam splitter is used. The beam splitters 130A and 130B illustrated here are each composed of a rectangular sheet or thin plate of equal size. However, the sizes of the beam splitter 130A and the beam splitter 130B may be different.

[0021] Specifically, the beam splitter 130A is arranged to face the retroreflective material 120B, and the beam splitter 130B is arranged to face the retroreflective material 120A. The beam splitter 130A illustrated here is arranged spaced apart so as to be parallel to the retroreflective material 120B, and the beam splitter 130B is arranged spaced apart so as to be parallel to the retroreflective material 120A. However, they do not necessarily have to be parallel.

[0022] The end portion FA of the beam splitter 130A and the end portion FB of the beam splitter 130B may be arranged to be in contact with each other, or the end portion FA and the end portion FB may be arranged to be separated from each other. For example, the respective end portions of the two beam splitters may be joined by an adhesive material, or one beam splitter may be bent to form two beam splitters.

[0023] The angles θC formed by the respective main surfaces of the beam splitters 130A and 130B, the sizes of the main surfaces of the beam splitters 130A and 130B, and the distances from the light source 110 to the beam splitters 130A and 130B are set such that the light emitted from the light source 110 can be sufficiently incident, and the light retroreflected by the retroreflective materials 120A and 120B can be sufficiently incident. When the tilt angles θA = θB, the angle θC = 2θA = 2θB, and the optical system of the display device 100 is symmetric about the normal line (optical axis) passing through the center of the light source 110.

[0024] Next, the operation of the display device of this embodiment will be described. FIG. 3 is a ray diagram when an aerial image is displayed, and here, only the rays emitted from the center of the emission surface of the light source 110 are shown. Also, solid lines indicate incident light, and dashed lines indicate retroreflected light. As shown in the figure, the light (image) emitted from the emission surface of the light source 110 in the normal direction (optical axis) is incident on each of a pair of beam splitters 130A and 130B.

[0025] The light reflected by the beam splitter 130A is incident on the opposing retroreflective material 120B, where it is retroreflected. The retroreflected light is incident on the beam splitter 130A, and the light transmitted through it forms an image to generate an aerial image PA. Also, the light reflected by the beam splitter 130B is incident on the opposing retroreflective material 120A, where it is retroreflected. The retroreflected light is incident on the beam splitter 130B, and the light transmitted through it forms an image to generate an aerial image PB.

[0026] The aerial image PA is generated at a position symmetric to the light source 110 with respect to the surface of the beam splitter 130A, and the aerial image PB is generated at a position symmetric to the light source 110 with respect to the surface of the beam splitter 130B. Also, since the aerial images PA and PB share the image emitted from the light source 110, they are aerial images of the same content.

[0027] Figure 4 is a ray diagram when viewing the aerial image from the viewpoint positions in two directions, left and right. The left user U1 located in the direction of the tilt angle θB of the retroreflective material 120B can observe the retroreflective material 120B through the beam splitter 130A from the viewpoint, so the aerial image PA can be visually recognized in the line-of-sight direction. Also, the right user U2 located in the direction of the tilt angle θA of the retroreflective material 120A can observe the retroreflective material 120A through the beam splitter 130B from the viewpoint, so the aerial image PB can be visually recognized in the line-of-sight direction.

[0028] Thus, according to this embodiment, by arranging a pair of retroreflective materials 120A and 120B that are inclined outward on both sides of the light source 110, and arranging a pair of beam splitters 130A and 130B so as to face the pair of retroreflective materials 120A and 120B, aerial images of the same content can be displayed in two directions, and in fact, a wide viewing angle of the aerial image can be realized. Also, depending on the arrangement of the optical system, two users can both view the aerial image from more directly in front, so there is an advantage that the content is easier to view. Furthermore, by sharing the expensive display light source among the optical system members of the aerial image, it is not necessary to use two light sources as in the conventional case (Fig. 1(B)), and the cost of the display device can be reduced.

[0029] In one aspect of this embodiment, when the light emitted from the light source 110 is polarized light (for example, the image of a liquid crystal display device), a retardation film, for example, a λ / 4 film, may be provided on the surfaces of the retroreflective materials 120A and 120B, and polarizing beam splitters may be used for the beam splitters 130A and 130B. A polarizing beam splitter transmits a part of the light in a certain polarization state and reflects the rest. The polarization direction of the polarizing beam splitter is determined in relation to the polarization direction of the light emitted from the light source 110. For example, the polarization direction of the light source 110 is set to be substantially orthogonal to the polarization direction of the polarizing beam splitter.

[0030] In the above embodiment, a set of retroreflective materials 120A and 120B are respectively arranged on the left and right sides of the light source 110 to display two aerial images in the horizontal direction. However, when displaying two aerial images in the vertical direction, a set of retroreflective materials 120A and 120B and a set of beam splitters 130A and 130B may be arranged in a positional relationship such that the display device 100 shown in FIG. 2 is rotated by 90 degrees.

[0031] Next, a modified example of the display device of this embodiment will be described. FIG. 5 is a top view of the display device 100A of the modified example. In the previous embodiment, the retroreflective surfaces of the retroreflective materials 120A and 120B were flat, but in the display device 100A of the modified example, the retroreflective materials 140A and 140B have curved surfaces or spherical surfaces with curved retroreflective surfaces. The curvature or the center of curvature of the retroreflective materials 140A and 140B is appropriately determined according to the viewing positions of the left and right users U1 and U2. By using such a retroreflective material with a curved surface shape, two aerial images can be displayed more on the front side.

[0032] In addition, the display device 100 / 100A of this embodiment can be attached, for example, to the interior space (for example, the dashboard or the instrument panel part) between the driver's seat 200 and the passenger seat 210 as shown in FIG. 6. The driver sitting on the driver's seat 200 and the passenger sitting on the passenger seat 210 can visually recognize the aerial images displayed by the display device 100 / 100A from their respective line-of-sight directions.

[0033] Furthermore, the display device of this embodiment can be applied not only to the in-vehicle space but also to devices and systems used for viewing from the left and right. For example, it can be applied in front of the seats of two-seater attractions, or in front of the seats of trains, buses, airplanes, etc.

[0034] As described above, the preferred embodiments of the present invention have been described in detail. However, the present invention is not limited to specific embodiments, and various modifications and changes are possible within the scope of the gist of the invention described in the claims.

Explanation of Reference Numerals

[0035] 100, 100A: Display device 110: Light source 120A, 120B, 140A, 140B: Retroreflective material 130A, 130B: Beam splitter 200: Driver's seat 210: Passenger seat PA, PB: Aerial images

Claims

1. A display device capable of displaying an aerial image using retroreflection, comprising: a light source that emits an image from an emission surface; a first retroreflective material disposed on one end side of the light source so as to be inclined outward at a first inclination angle with respect to the normal of the emission surface; a second retroreflective material disposed on the other end side of the light source so as to be inclined outward at a second inclination angle with respect to the normal of the emission surface; a first optical member that separates incident light into reflected light and transmitted light, the first optical member being disposed so as to face the first retroreflective material; a second optical member that separates incident light into reflected light and transmitted light, the second optical member being disposed so as to face the second retroreflective material; and a display device including the above.

2. The display device according to claim 1, wherein the first optical member is disposed parallel to the first retroreflective material, and the second optical member is disposed parallel to the second retroreflective material.

3. The display device according to claim 1, wherein the first and second retroreflective materials are spherical or curved.

4. The display device according to claim 1, wherein the display device displays a first aerial image in the direction in which the retroreflective surface of the first retroreflective material faces, and displays a second aerial image in the direction in which the retroreflective surface of the second retroreflective material faces, and the first aerial image and the second aerial image are the same.

5. The display device according to claim 1, wherein the first and second optical members are a half mirror, a beam splitter, or a polarizing beam splitter.

6. The display device according to claim 1, wherein the display device is disposed in the vehicle interior space between the driver's seat and the passenger seat.

Images