Indication device

Abstract

The present invention provides a display device that can prevent a decrease in the brightness and image quality of an aerial image depending on the angle from which the observer views it. [Solution] The display device 100 according to the present invention displays an aerial image P using retroreflection. The display device 100 includes a light source 120 and a plurality of retroreflective materials 130 arranged inside a housing 110, and a beam splitter 140 arranged on the surface of the housing 110. The retroreflective materials 130 include at least three retroreflective materials 130-1, 130-2, 130-3, 130-4, and 130-5 arranged within a range in which the aerial image P can be observed, and at least one side of the retroreflective material is in a positional relationship that overlaps with the side of an adjacent retroreflective material in front.

Description

Technical Field

[0001] The present invention relates to a display device that displays a virtual image by retroreflection, and particularly to an effective arrangement of a retroreflective material.

Background Art

[0002] Aerial Imaging by Retro - Reflection (AIRR) is known. For example, in the aerial imaging device of Patent Document 1, a decorative sheet 30 is disposed between an imaging element 20 and an imaging position P so that the imaging element 20 is not observed from the outside.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] FIG. 1 is a top view schematically showing the internal configuration of a conventional AIRR - type display device. The display device 10 includes a rectangular housing 20. Inside the housing 20, a light source 30 and a retroreflective material 40 are disposed, and a beam splitter (or a half - mirror) 50 is attached to the surface of the housing 20. The original image of the virtual image P output from the light source 30 is reflected by the beam splitter 50, the reflected light is retroreflected by the retroreflective material 40, the retroreflected light passes through the beam splitter 50, and the virtual image P is formed.

[0005] The aerial image P is formed at a position symmetrical to the light source 30 with respect to the surface of the beam splitter 50. The range in which observer U can see the aerial image P is limited to the range in which the retroreflective material 40 can be seen from observer U's viewpoint through the beam splitter 50. In the example shown in the figure, observer U1 can see the aerial image P within the field of view S1, observer U2 can see the aerial image P within the field of view S2, and observer U3 can see the aerial image P within the field of view S3. Furthermore, at positions outside of observer U1 and outside of observer U3, the retroreflective material 40 cannot be seen, and therefore the aerial image P cannot be observed.

[0006] In such conventional display devices 10, the retroreflective surface of the retroreflective material 40 is planar, which presents a problem in that the brightness and image quality of the aerial image P decrease significantly depending on the angle at which the observer U views the aerial image P. One reason for this is that the retroreflective properties (the ability to return incident light at the same angle) of the retroreflective material 40 decrease depending on the angle at which the aerial image P is viewed. The best brightness and image quality occur when the angle of the retroreflective material 40 in the line of sight of the observer U is perpendicular to the line of sight, but if the retroreflective material 40 is planar, the angle between the line of sight and the retroreflective material is not necessarily perpendicular.

[0007] The present invention aims to solve these conventional problems and provide a display device that can prevent a decrease in the brightness and image quality of an aerial image depending on the viewing angle of the observer. [Means for solving the problem]

[0008] The display device according to the present invention is capable of displaying an aerial image using retroreflection and comprises a light source, a beam splitter that reflects light output from the light source, and a plurality of retroreflective materials that reflect light from the beam splitter in the same direction as the incident light, wherein the plurality of retroreflective materials include at least three retroreflective materials arranged within a range in which the aerial image can be observed, and at least one side of the retroreflective materials is in a positional relationship that overlaps with the side of an adjacent retroreflective material. [Effects of the Invention]

[0009] According to the present invention, at least three retroreflective materials are arranged within the range in which the aerial image can be observed. This suppresses the reduction of retroreflective light from the retroreflective materials depending on the observer's viewing angle, thereby preventing a decrease in the brightness and image quality of the aerial image. [Brief explanation of the drawing]

[0010] [Figure 1] This is a top view showing a schematic configuration of a conventional AIRR-type display device. [Figure 2] Figure 2(A) is a schematic top view showing the configuration of a display device according to the first embodiment of the present invention, and Figure 2(B) is a diagram illustrating a preferred arrangement example of a plurality of retroreflective materials. [Figure 3] Figure 3(A) shows an example of an aerial image when the side (edge) of the retroreflective material is exposed, and Figure 3(B) shows an example of an aerial image when the side (edge) of the retroreflective material according to this embodiment is covered by an adjacent retroreflective material. [Figure 4] Figure 4(A) is a front view of a single retroreflective material, Figure 4(B) is a side view of a single retroreflective material, and Figure 4(C) is a perspective view showing a pseudo-three-dimensional curved retroreflective surface composed of multiple retroreflective materials. [Figure 5] The configuration of the base for supporting the retroreflective material in this embodiment is shown in Figure 5(A), Figure 5(B), Figure 5(C), and Figure 5(A). Figure 5(A) is a top view of the base, Figure 5(B) is a front view thereof, and Figure 5(C) is a side view thereof. [Figure 6] This figure shows another example of the arrangement of the retroreflective material in this embodiment. [Figure 7] This is a top view showing a schematic configuration of a display device according to a second embodiment of the present invention. [Modes for carrying out the invention]

[0011] Next, embodiments of the present invention will be described. In one embodiment of the present invention, the display device disassembles a retroreflective material that was originally on the same plane into small parts (for example, strips) and arranges them so that the angle of the retroreflective material is perpendicular to the observer's line of sight. Furthermore, the sides (edges) of the cuts are not visible from the intended viewing direction so that the joints of each part are not noticeable. This suppresses a decrease in the brightness and image quality of the aerial image. It should be noted that the drawings referenced in the following description of embodiments include exaggerations to facilitate understanding of the invention and do not represent the shape or scale of the actual product. [Examples]

[0012] Next, embodiments of the present invention will be described in detail. Figure 2(A) is a top view showing the schematic configuration of a display device according to the first embodiment of the present invention, and the figure schematically represents each part so that the internal configuration of the housing can be seen.

[0013] The display device 100 of this embodiment comprises a housing 110, a light source 120 arranged inside the housing 110, a plurality of retroreflective materials 130-1, 130-2, 130-3, 130-4, 130-5 (collectively referred to as retroreflective material 130), and a beam splitter 140. The shape and size of the housing 110 are not limited, but in the example shown in the figure, the housing 110 is generally rectangular in shape and houses the light source 120 and the retroreflective material 130 in its internal space. A beam splitter 140 is also arranged on one side of the housing 110, and an aerial image P is displayed at a position symmetrical to the light source 120 with respect to the surface of the beam splitter 140.

[0014] The light source 120 generates the original image of the aerial image P, and its configuration is not particularly limited, but examples include an LED or organic EL display, a projector, or an LED unit with multiple LEDs arranged in two dimensions. In the example shown in the figure, the light source 120 is a display placed inside the beam splitter 140, and this display outputs the original image of the aerial image P toward the beam splitter 140.

[0015] The beam splitter 140 is attached to the surface of the housing 110 so as to receive light from the light source 120. The beam splitter 140 is configured by forming a dielectric multilayer film, an antireflection film, etc. on the front or back surface of a substrate such as a flat glass or plastic. The beam splitter 140 may be a half mirror in which the amount of reflected light and the amount of transmitted light are substantially equal, or a beam splitter in which the ratio of the amount of reflected light to the amount of transmitted light is different, or a polarizing beam splitter.

[0016] The retroreflective material 130 is an optical member that reflects light in the same direction as the incident light, and its configuration is not particularly limited. For example, it is configured by a triangular pyramid type retroreflective element, a full cube corner type retroreflective element, etc. Further, the retroreflective material 130 may have a retardation film such as a λ / 4 plate attached to its surface.

[0017] A characteristic configuration in this embodiment is to arrange a plurality of retroreflective materials 130-1 to 130-5 within the range where the observer U inside the housing 110 can observe the aerial image P. In this embodiment, instead of using one planar retroreflective material 40 as shown in FIG. 1 described in the prior art, such a retroreflective material 40 is decomposed into at least three or more small retroreflective materials 130, and these are arranged inside the housing 110. Each of the retroreflective materials 130 has, for example, a strip shape, and as shown in FIG. 2(A), is arranged along the left and right inner walls centering on the corner portion of the housing 110.

[0018] In this example, the retroreflective material 130-3 is disposed at the corner of the housing 110, and two retroreflective materials 130-1, 130-2 and 130-4, 130-5 are disposed on both sides thereof, respectively. The retroreflective material 130-1 disposed at one end is positioned such that its retroreflective surface is at an angle perpendicular to the line-of-sight direction of the observer U3 (the center of the viewing angle S3), and the retroreflective material 130-5 disposed at the other end is positioned such that its retroreflective surface is at an angle perpendicular to the line-of-sight direction of the observer U1 (the center of the viewing angle S1). The retroreflective material 130-3 disposed in the center is positioned such that its retroreflective surface is at an angle perpendicular to the line-of-sight direction of the observer U2 (the center of the viewing angle S2).

[0019] The range within which the observer U can observe the aerial image P is limited to the range within which the observer U can see the retroreflective material 130 through the aerial image P. FIG. 2(A) shows the range within which the aerial image P can be observed from the position of the observer U1 to the position of the observer U3. That is, the position of the observer U1 is the boundary at which the retroreflective material 130-5 can be seen at the viewing angle S1, and the position of the observer U3 is the boundary at which the retroreflective material 130-1 can be seen at the viewing angle S3.

[0020] Thus, by disposing the retroreflective materials 130-1, 130-2, 130-4, 130-5 on both sides of the central retroreflective material 130-3 such that the angles of the retroreflective surfaces gradually differ, compared with the case of disposing one planar retroreflective material of the conventional structure, the angle of the retroreflective material with respect to the line-of-sight of the observer can be made closer to perpendicular. Thereby, the decrease in the retroreflective light from the retroreflective material due to the viewing angle of the observer is suppressed, and the degradation of the luminance and video quality of the aerial image P can be suppressed.

[0021] Also, as can be easily understood by those skilled in the art, by increasing the number of retroreflective materials and further subdividing the retroreflective materials, it is possible to make the angle changes of the plurality of retroreflective materials smaller. Thereby, within the range where the observer can observe the aerial image P, the angle of the retroreflective material with respect to the line-of-sight of the observer can be made closer to perpendicular.

[0022] Next, a preferred embodiment of this model will be described. Figure 2(B) is a diagram showing a preferred arrangement example of the retroreflective material shown in Figure 2(A). As shown in the figure, the retroreflective material 130 is arranged such that its side (edge) is covered by the adjacent retroreflective material. As shown in the figure, one side edge E2 of the central retroreflective material 130-3 is covered by one side of the adjacent retroreflective material 130-2 in front, and the other side edge E1 of the retroreflective material 130-2 is covered by one side of the adjacent retroreflective material 130-1 in front. Similarly, the other side edge E3 of the central retroreflective material 130-3 is covered by one side of the adjacent retroreflective material 130-4 in front, and the other side edge E4 of the retroreflective material 130-4 is covered by one side of the adjacent retroreflective material 130-5 in front.

[0023] Figure 3(A) shows an example of an aerial image when the side of a retroreflective material is not covered by the side of an adjacent retroreflective material and its edge is exposed, and Figure 3(B) shows an example of an aerial image when the side of the retroreflective material in this embodiment overlaps with the side of an adjacent retroreflective material.

[0024] If the sides of retroreflective materials are not overlapped and their edges are exposed, the region of the joint between the edges of adjacent retroreflective materials will not be imaged as an aerial image. As a result, a line Q corresponding to the joint between the edges will appear in the aerial image P, and the image quality of the aerial image P will decrease. In contrast, as in this embodiment, when the sides of retroreflective materials overlap the sides of adjacent retroreflective materials, no non-imaged region due to the joint is created between the retroreflective materials. Therefore, no joint line appears in the aerial image P, and the image quality can be maintained.

[0025] In this way, by overlapping the side of one retroreflective material with the side of the adjacent retroreflective material in front, it is possible to prevent the formation of non-imaging regions at the joints between retroreflective materials, thereby preventing deterioration of the image quality of the aerial image P.

[0026] In the above embodiment, the retroreflective material 130 is shown as being in the shape of a strip, but this is just one example, and the retroreflective material 130 may be in other shapes. For example, the retroreflective material may be trapezoidal, fan-shaped, etc. Also, each of the retroreflective materials 130 may be the same size, or they may be of different sizes. For example, the shorter side of the central retroreflective material 130-3 may be larger than or smaller than the shorter sides of the adjacent retroreflective materials 130-2 and 130-4.

[0027] Next, other preferred embodiments of this model will be described. Figure 4(A) is a front view of the retroreflective material, Figure 4(B) is a side view of the retroreflective material, and Figure 4(C) is a perspective view of the retroreflective material forming a three-dimensional curved surface. As shown in Figures 4(A) and (B), one retroreflective material 130-i has a generally rectangular shape and is curved along its longitudinal direction to form a curved surface. As shown in Figure 4(C), retroreflective materials 130-1, 130-2, 130-3, and 130-4 are arranged so as to spread out in a fan shape on one side of retroreflective material 130-5, and retroreflective materials 130-6, 130-7, and 130-8 are arranged so as to spread out in a fan shape on the other side. In this way, by combining multiple strip-shaped retroreflective materials having curved surfaces, a retroreflective material having a pseudo-three-dimensional curved surface can be constructed. In this example as well, the side of one retroreflective material can be arranged so that it overlaps with the side of an adjacent retroreflective material.

[0028] Next, a method for attaching multiple retroreflective materials to the housing will be described. The method of attaching the retroreflective materials is not particularly limited, but for example, they can be attached and fixed to a support member such as a base. Figure 5 shows an example of a base for attaching retroreflective materials that constitute the three-dimensional curved surface shown in Figure 4(C), where Figure 5(A) is a top view of the base, Figure 5(B) is a front view thereof, and Figure 5(C) is a side view thereof.

[0029] The base 200 includes a side surface 230 between the top surface 210 and a bottom surface 220 that is somewhat larger than the top surface 210, on which eight curved mounting surfaces 230-1, 230-2, 230-3, 230-4, 230-5, 230-6, 230-7, 230-8 (collectively referred to as mounting surface 230) are formed. On one side of the central mounting surface 230-3, mounting surfaces 230-2 and 230-1 are formed via steps, and on the other side, mounting surfaces 230-4, 230-5, 230-6, 230-7, 230-8 are formed via steps, respectively.

[0030] Mounting surfaces 230-1, 230-2, 230-3, 230-4, 230-5, 230-6, 230-7, and 230-8 define the shape of the retroreflective surfaces of the retroreflective materials 130-1, 130-2, 130-3, 130-4, 130-5, 130-6, 130-7, and 130-8, and the retroreflective material 130 is fixed to the mounting surface 230, for example, by double-sided adhesive or by mechanical means. Even if it is difficult to shape the retroreflective material 130, or if the retroreflective material 130 is prone to elastic deformation, fixing the retroreflective material 130 to the mounting surface 230 allows the retroreflective surface of the retroreflective material 130 to conform to the shape of the mounting surface 230. Furthermore, steps are formed at each boundary of the mounting surface 230, and these steps allow the sides of the retroreflective material to overlap with the sides of adjacent retroreflective materials. In this way, the base 200 to which the retroreflective material 130 is fixed is placed inside the housing 110.

[0031] In the above embodiment, the longitudinal directions of each retroreflective material 130 were arranged in the vertical direction of the drawing, but this is just one example, and other arrangements are also possible. For example, as shown in Figures 6(A) and (B), the longitudinal directions of each retroreflective material 130-1 to 130-5 may be arranged in the horizontal direction of the drawing, or they may be arranged diagonally. In this case as well, it is desirable that the sides of the retroreflective materials overlap with the sides of adjacent retroreflective materials.

[0032] Figure 7 is a schematic top view showing the configuration of a display device according to a second embodiment of the present invention. The display device 100A of this embodiment differs from the embodiment described above in that a plurality of retroreflective materials 200 are arranged along concentric circles C centered on the imaging position of the aerial image P. The shape, size, and number of retroreflective materials 200 are not particularly limited, but for example, the retroreflective materials 200 are in the shape of strips, and a plurality of strip-shaped retroreflective materials 200 are arranged along concentric circles C at approximately equal distances from the center of the imaging position of the aerial image P. Each of the plurality of retroreflective materials 200 is arranged to be in contact with or in close proximity to the side of an adjacent retroreflective material, so as not to create a gap at the joint of the retroreflective materials that would be a non-imaging region of the aerial image. However, as described in the previous embodiment, the side of a retroreflective material may overlap with the side of an adjacent retroreflective member.

[0033] In the figure, the position of observer U1 is one boundary from which one end of the retroreflective material 200 can be seen via the aerial image P, and the position of observer U7 is the other boundary from which the other end of the retroreflective material can be seen via the aerial image P. In other words, the range from observer U1 to observer U7 is the range from which the aerial image P can be observed.

[0034] According to this embodiment, by arranging multiple retroreflective materials concentrically so that the distance from the aerial image P to the retroreflective material 200 remains constant, partial image degradation can be prevented, and the image quality of the aerial image can be maintained even when the observer changes the viewing angle.

[0035] Although preferred embodiments of the present invention have been described in detail above, the present invention is not limited to any particular embodiment, and various modifications and changes are possible within the scope of the gist of the invention as described in the claims. [Explanation of symbols]

[0036] 100, 100A: Display device; 110: Enclosure 120: Light source 130: Retroreflective material 140: Beam splitter 200: Base 210:Top 220:Bottom 230: Side (mounting surface) P: Aerial image U: Observer

Claims

1. A display device capable of displaying an aerial image using retroreflection, Light source and A beam splitter that reflects the light output from the aforementioned light source, The beam splitter has a plurality of retroreflective materials that reflect light from the beam splitter in the same direction as the incident light, A display device in which the plurality of retroreflective materials include at least three retroreflective materials arranged within a range from which the aerial image can be observed, and at least one side of the retroreflective material is in a positional relationship with the side of an adjacent retroreflective material.

2. The display device according to claim 1, wherein each of the plurality of retroreflective materials is arranged at an angle perpendicular to the observer's line of sight when the retroreflective material is observed from above.

3. The display device according to claim 2, wherein each of the plurality of retroreflective materials is arranged on both sides of the central retroreflective material such that the angles of the retroreflective surfaces gradually differ.

4. The display device according to claim 1, wherein each of the plurality of retroreflective materials is arranged concentrically with respect to the aerial image when the retroreflective material is observed from above.

5. The display device according to claim 1, wherein each of the plurality of retroreflective materials has a strip-shaped form with a curved surface formed in the longitudinal direction, and a pseudo three-dimensional curved surface is formed by the plurality of strip-shaped retroreflective materials.

6. The display device according to claim 1, further comprising a base having a plurality of mounting surfaces for attaching each of the plurality of retroreflective materials, each of the mounting surfaces defining the shape of the retroreflective surface of each of the plurality of retroreflective materials.

Images