Display device

Abstract

To provide a display device which makes it easy for a viewer to feel as if an aerial image is displayed in a space between a light splitting unit and the viewer (at an aerial display position, in particular) rather than on a retroreflective unit even in the presence of a non-retroreflective section in the retroreflective unit constituted of multiple retroreflectors.SOLUTION: A display device 100 comprises: a light source 10; a retroreflective unit 20; and a light splitting unit 30 designed to reflect or transmit emitted light L1 emitted from the light source 10 toward the retroreflective unit 20 and transmit or reflect retroreflected light L2 reflected from the retroreflective unit 20. The display device is configured to display an aerial image AI in a space. The retroreflective unit 20 consists of multiple retroreflectors 21 to 21. The display device is configured to move the retroreflective unit 20 within a range that maintains retroreflectivity of the retroreflective unit 20 when displaying the aerial image AI.SELECTED DRAWING: Figure 4A

Description

[Technical field]

[0001] The present invention relates to a display device that displays an aerial image in space by utilizing retroreflection. [Background technology]

[0002] 2. Description of the Related Art Display devices that perform aerial imaging by retro-reflection (AIRR), which displays an aerial image in space by utilizing retro-reflection, have been known for some time (see, for example, Patent Document 1).

[0003] In other words, a display device using retroreflection comprises a light source, a retroreflecting section, and a light branching section that reflects or transmits light emitted from the light source toward the retroreflecting section, and transmits or reflects the retroreflected light reflected from the retroreflecting section, and displays an aerial image in space.

[0004] In recent years, display devices that perform this type of aerial display have been attracting attention in fields such as communications and broadcasting, entertainment, art, and medicine as display devices that can utilize the environment and space to display images in the air that can be seen without the need for special glasses.

[0005] Furthermore, in a display device that performs an aerial display, it is desirable to increase the display size of the aerial display so that it can be viewed from a distance. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-47440 Summary of the Invention [Problem to be solved by the invention]

[0007] An example of a large display device may be a display device that is installed outdoors (e.g., on a road) and provides public information (e.g., information about the road) (e.g., a traffic information display device that displays traffic information such as no entry signs and warnings).

[0008] A large display device requires a large size retroreflector (retroreflector plate) that acts as a retroreflector, but this has the following disadvantages.

[0009] That is, although it is theoretically possible to produce a retroreflector that is large enough to have no non-retroreflective portions, this is not practical when costs and other factors are taken into consideration.

[0010] 11A and 11B are plan views showing an example and another example of the non-retroreflective portion 40 of the retroreflector 21, respectively.

[0011] As shown in FIG. 11A, polygonal retroreflectors 21 can only be manufactured in small sizes (for example, about 50 cm) due to manufacturing reasons (such as the inability to enlarge the mold). For this reason, in a large display device, it is considered to use a large-sized (for example, 3 m to 4 m) retroreflector 20 composed of a plurality of small-sized retroreflectors 21-21 (formed by joining them together). Also, as shown in FIG. 11B, sheet-shaped retroreflectors 21 can only be manufactured in small widths due to manufacturing problems. For this reason, in a large display device, it is considered to use a large-sized (for example, 3 m to 4 m) retroreflector 20 composed of a plurality of small-sized retroreflectors 21-21 (formed by joining them together).

[0012] Incidentally, in the large-sized retroreflective section 20 constituted by a plurality of small polygonal retroreflectors 21 as shown in Fig. 11A, there are inevitably non-retroreflective sections 40 that do not have a retroreflective function. Similarly, in the large-sized retroreflective section 20 constituted by a plurality of small sheet-like retroreflectors 21 as shown in Fig. 11B, there are also non-retroreflective sections 40.

[0013] In detail, the peripheral parts of the retroreflectors 21 and the joint parts 41 between adjacent retroreflectors 21, 21 do not have a retroreflective function (are not retroreflective), and are visually recognized by the viewer as non-image parts (e.g., black lines) corresponding to the non-retroreflecting parts 40 in the retroreflecting part 20. In this case, the viewer should feel that the aerial image is displayed between the light branching part and the viewer (particularly at the aerial display position) (as if the aerial image is floating), but due to the influence of the non-image parts (e.g., black lines) corresponding to the non-retroreflecting parts 40 in the retroreflecting part 20, the viewer feels that the aerial image is displayed on the retroreflecting part 20 (as if the aerial image is floating) rather than between the light branching part and the viewer (particularly at the aerial display position).

[0014] Therefore, the present invention aims to provide a display device that can easily make the viewer feel as if the aerial image is being displayed between the optical branching section and the viewer (particularly at the aerial display position) rather than in the retroreflective section, even if a non-retroreflective section is present in a retroreflective section composed of multiple retroreflectors. [Means for solving the problem]

[0015] In order to solve the above problems, the display device of the present invention is a display device that displays an aerial image at an aerial display position in space, comprising a light source, a retroreflective unit, and a light branching unit that reflects or transmits light emitted from the light source toward the retroreflective unit, and transmits or reflects the retroreflective light reflected from the retroreflective unit, wherein the retroreflective unit is composed of a plurality of retroreflectors, and is configured to move the retroreflective unit within a range that maintains the retroreflective performance of the retroreflective unit when displaying the aerial image. Effect of the Invention

[0016] According to the present invention, even if a non-retroreflective portion is present in a retroreflective portion composed of multiple retroreflectors, it is possible to make the viewer easily perceive the aerial image as being displayed between the optical branching portion and the viewer (particularly at the aerial display position) rather than at the retroreflective portion. [Brief description of the drawings]

[0017] [Figure 1A] 1 is a schematic diagram showing an example of a display device having a basic configuration according to an embodiment of the present invention; [Figure 1B] FIG. 11 is a schematic diagram showing another example of a display device having a basic configuration according to an embodiment of the present invention. [Figure 1C] FIG. 13 is a schematic diagram showing still another example of a display device having a basic configuration according to an embodiment of the present invention. [Figure 2A] 4 is a cross-sectional view showing an example of a retroreflective structure at a joint between adjacent retroreflectors in a retroreflective section. FIG. [Figure 2B] 10 is a cross-sectional view showing another example of a retroreflective structure at a joint portion between adjacent retroreflectors in a retroreflective section. FIG. [Figure 2C] FIG. 2 is a plan view showing a schematic configuration of an example of a retroreflective portion. [Figure 2D] FIG. 2 is a front view illustrating a schematic view of an aerial image viewed by a viewer. [Figure 3A] FIG. 2 is a schematic front view showing a first mode of the moving device for the display device according to the first embodiment. [Figure 3B] FIG. 4 is a schematic front view showing a second mode of the moving device for the display device according to the first embodiment. [Figure 3C] FIG. 11 is a schematic front view showing a third mode of the moving device for the display device according to the first embodiment. [Figure 3D] FIG. 11 is a schematic front view showing a fourth mode of the moving device for the display device according to the first embodiment. [Figure 3E] FIG. 2 is a side view illustrating an example of a vibration driver in the movement device of the display device according to the first embodiment. [Figure 3F] 10 is a side view illustrating a schematic diagram of another example of a vibration driver in the movement device of the display device according to the first embodiment. FIG. [Figure 4A] FIG. 11 is a perspective view showing a schematic diagram of a first mode of a moving device for a display device according to a second embodiment. [Figure 4B] FIG. 11 is a front view showing a schematic diagram of a first mode of a moving device for a display device according to a second embodiment. [Figure 4C] FIG. 13 is a perspective view illustrating a second mode of the moving device for the display device according to the second embodiment. [Figure 4D] FIG. 11 is a front view showing a schematic diagram of a second mode of the moving device for the display device according to the second embodiment. [Figure 4E] FIG. 13 is a front view showing a schematic diagram of a third mode of the moving device for the display device according to the second embodiment. [Figure 4F] FIG. 11 is a side view diagrammatically illustrating a third mode of the moving device for the display device according to the second embodiment. [Figure 4G] FIG. 13 is a front view showing a schematic modification of the third mode of the moving device of the display device according to the second embodiment. [Figure 4H] FIG. 1 is a side view showing a schematic diagram of an example of a combination of a rotating device and a vibrating device. [Figure 4I] FIG. 1 is a front view showing a schematic example of a combination of a rotating device and a vibrating device. [Diagram 5] FIG. 1 is a system block diagram showing a schematic configuration of a display system including display devices according to a first embodiment and a second embodiment. [Figure 6A] 13 is a graph showing an example of the relationship between the rotation speed of a DC motor used as a rotation drive unit and energy supplied to the DC motor in the display device according to the second embodiment. [Figure 6B] FIG. 2 is a circuit diagram showing a basic configuration of a drive circuit for driving a DC motor. [Figure 7A] FIG. 11 is a side view illustrating an example in which a plurality of retroreflectors are individually provided in a display device according to a third embodiment. [Figure 7B] FIG. 11 is a side view diagrammatically illustrating another example in which a plurality of retroreflectors are individually provided in the display device according to the third embodiment. [Figure 7C] FIG. 13 is a side view diagrammatically illustrating still another example in which a plurality of retroreflectors are individually provided in the display device according to the third embodiment. [Figure 8] 1 is a diagram showing rotation speed, movement speed and frequency. [Figure 9A] 1 is a chart showing evaluation results 1-1 (magnification / second) in an experimental example. [Figure 9B] 13 is a graph showing evaluation results 1-1 (magnification / second) in an experimental example. [Figure 9C] 13 is a diagram and a graph showing evaluation results 1-2 (movement speed) in an experimental example. [Figure 9D] 13 is a diagram and a graph showing evaluation results 1-2 (movement speed) in an experimental example. [Figure 10A] 13 is a chart showing evaluation results 2-1 (magnification / second) in a reference example. [Figure 10B] 13 is a graph showing evaluation results 2-1 (magnification / second) in a reference example. [Figure 10C] 13 is a table showing evaluation results 2-2 (movement speed) in a reference example. [Figure 10D] 13 is a graph showing evaluation results 2-2 (movement speed) in a reference example. [Figure 11A] FIG. 2 is a plan view showing a non-retroreflective portion of an example of a retroreflector. [Figure 11B] 13 is a plan view showing a non-retroreflective portion of another example of a retroreflector. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, the same components are denoted by the same reference numerals. The names and functions of the components are also the same. Therefore, detailed description thereof will not be repeated.

[0019] 1A, 1B, and 1C are schematic diagrams showing an example, another example, and yet another example of a display device 100 having a basic configuration according to an embodiment of the present invention, respectively. Note that in the drawings, the same reference numerals are used to designate members having substantially the same configuration.

[0020] As shown in Fig. 1A to Fig. 1C, the display device 100 includes one or more (multiple in this example) light sources 10, a retroreflector 20 (reflector), and a light branching unit 30 (beam splitter in this example). In the display device 100 shown in Fig. 1A and Fig. 1C, the light branching unit 30 reflects the outgoing light L1 to L1 emitted from the light sources 10 toward the retroreflector 20 and transmits the retroreflected light L2 to L2 reflected from the retroreflector 20. In the display device 100 shown in Fig. 1B, the light branching unit 30 transmits the outgoing light L1 to L1 emitted from the light sources 10 toward the retroreflector 20 and reflects the retroreflected light L2 to L2 reflected from the retroreflector 20 toward the aerial display position P.

[0021] 1A to 1C displays an aerial image AI in space. That is, the display device 100 displays an aerial image AI at an aerial display position P symmetrical to the light sources 10 with respect to the optical branching unit 30.

[0022] 1A and 1C, outgoing light L1-L1 emitted from light sources 10-10 is reflected by light branching unit 30, and reflected light L3-L3 reflected by light branching unit 30 is made incident on retroreflection unit 20. Then, reflected light L3-L3 made incident on retroreflection unit 20 is reflected by retroreflection unit 20 in the same direction as the incident direction, and retroreflected light L2-L2 reflected by retroreflection unit 20 is transmitted through light branching unit 30, and an aerial image AI is displayed at aerial display position P symmetrical to light sources 10-10 with respect to light branching unit 30.

[0023] 1B, outgoing light L1-L1 emitted from light sources 10-10 is transmitted through light branching unit 30, and transmitted light L4-L4 transmitted through light branching unit 30 is made incident on retroreflection unit 20. The retroreflected light L2-L2 reflected by retroreflection unit 20 is reflected by light branching unit 30 in the same direction as the incident direction, and an aerial image AI is displayed at aerial display position P symmetrical to light sources 10-10 with respect to light branching unit 30.

[0024] The light sources 10 constitute a display unit 110 having a display surface 111, and a plurality of light sources 10 are arranged in parallel along the display surface 111 in the display unit 110. The display unit 110 displays a display image IM. The number and relative arrangement of the light sources 10 are not particularly limited. In this example, the light sources 10 are light-emitting elements (specifically, light-emitting diodes: LEDs), but are not particularly limited thereto.

[0025] The display device 100 is arranged such that the display unit 110 and the retroreflective unit 20 are arranged so that the light-emitting side of the display unit 110 and the light-reflecting side of the retroreflective unit 20 face each other and are at a predetermined acute angle (see Figures 1A and 1C) or parallel (see Figure 1B).

[0026] The light branching unit 30 is a plate-like member, and in this example, is a beam splitter. However, the light branching unit 30 is not limited to this, and may be, for example, an optical element such as a half mirror.

[0027] FIG. 2A is a cross-sectional view showing an example (20a) of a retroreflective structure at a joint 41 between adjacent retroreflectors 21, 21 in a retroreflective section 20. As shown in FIG.

[0028] As shown in Fig. 2A, the retroreflective section 20 has a conventionally known retroreflective structure 20a. In this example, the retroreflective structure 20a has a plurality of prism elements 201-201. A reflective film 201a is formed on the inclined surfaces (21a1, 21a2)-(21a1, 21a2) of the plurality of prism elements 201-201. The plurality of prism elements 201-201 are connected together along the surface direction F, and the inclined surfaces (21a1, 21a2)-(21a1, 21a2) of the plurality of prism elements 201-201 form the retroreflective surface 21a. A resin layer 202 (top film) is formed on the retroreflective surface 21a.

[0029] In the retroreflective structure 20a shown in Figure 2A, incident light La that has passed through the resin layer 202 is reflected by the reflective film 201a on one inclined surface 21a1, and then is reflected by the reflective film 201a on the other inclined surface 21a2 opposite the one inclined surface 21a1, and the reflected reflected light Lb is emitted in a direction parallel to the incident light La.

[0030] The structure of the retroreflective section 20 is not particularly limited as long as it can reflect light incident on the retroreflective section 20 in the same direction as the incident direction.

[0031] FIG. 2B is a cross-sectional view showing another example ( 20 b ) of the retroreflective structure at joint 41 between adjacent retroreflectors 21 , 21 in retroreflective section 20 .

[0032] As shown in Fig. 2B, the retroreflective section 20 includes a conventionally known retroreflective structure 20b. In this example, the retroreflective structure 20b includes a plurality of solid spherical glass beads 203-203. A reflective film 203a is formed on the lower curved surfaces 21b1-21b1 of the glass beads 203-203. The glass beads 203-203 are connected together along the surface direction F, and the curved surfaces 21b1-21b1 form the retroreflective surface 21b.

[0033] In retroreflective structure 20b shown in FIG. 2B, incident light La is reflected by reflective film 203a on curved surface 21b1 of one glass bead 203, and reflected light Lb is emitted in a direction parallel to the incident light La.

[0034] Materials that can be used for the retroreflective portion 20 are not particularly limited as long as they are retroreflective, and examples thereof include optical glass, polycarbonate (PC) resin, and polymethylmethacrylate resin (PMMA).

[0035] The display device 100 of this embodiment is a large display device (e.g., a traffic information display device that displays traffic information such as no entry signs and caution notices) that is installed outdoors (e.g., on a road) and provides public information (e.g., information related to the road).

[0036] Fig. 2C is a plan view showing a schematic configuration of an example of the retroreflection section 20. Fig. 2D is a front view showing a schematic view of an aerial image AI visually recognized by a viewer S.

[0037] The retroreflective section 20 shown in Fig. 2C is a plate-like large-sized (e.g., 3m to 4m) retroreflective member 21-21 that is made up of a plurality of small-sized (about 50cm in this example) polygonal (hexagonal) retroreflective members 21-21. In this example, the retroreflective member 20 is formed by connecting a plurality of retroreflective members 21-21. Specifically, the retroreflective member 20 is formed by arranging a plurality of retroreflective members 21-21 side by side on a base material 22 (e.g., an acrylic plate) (see Fig. 2C).

[0038] However, in a large-sized retroreflective section 20 composed of a plurality of small-sized retroreflectors 21-21, there are inevitably non-retroreflective sections 40 that do not have a retroreflective function. In detail, the peripheral parts of the retroreflectors 21-21 and the joints 41 between adjacent retroreflectors 21, 21 do not have a retroreflective function (are not retroreflective), and as shown in Fig. 2D, they are visually recognized by a viewer S (see Figs. 1A to 1C) in the aerial image AI as non-image sections AN (e.g., black lines) that correspond to the non-retroreflective sections 40 in the retroreflective section 20. In this case, the viewer S should perceive the aerial image AI as being displayed between the optical branching unit 30 and the viewer S (particularly at aerial display position P (see Figures 1A to 1C)) (as if the aerial image AI is floating), but due to the influence of the non-image area AN (e.g., a black line) (see Figure 2D) corresponding to the non-retroreflective area 40 in the retroreflective unit 20, the viewer S will perceive the aerial image AI as being displayed on the retroreflective unit 20 (see Figures 1A to 1C) (as if the aerial image AI is floating) rather than between the optical branching unit 30 and the viewer S (particularly at aerial display position P).

[0039] In this regard, the display device 100 according to the present embodiment is configured to move the retroreflector 20 within a range that maintains the retroreflectivity of the retroreflector 20 when displaying the aerial image AI. Here, from the viewpoint of maintaining the reflection direction of the retroreflected light L2-L2, the posture of the moving retroreflector 20 is maintained.

[0040] In this embodiment, since the retroreflective section 20 composed of a plurality of retroreflectors 21-21 is moved, the non-retroreflective sections 40 (41) of the retroreflectors 21-21 can also be moved, making it difficult for the viewer S to notice the non-retroreflective sections 40 (41) in the retroreflective section 20. Here, the non-retroreflective sections 40 refer to the joint sections 41 between adjacent retroreflectors 21, 21 when the retroreflective section 20 is formed by joining a plurality of retroreflectors 21-21 as in this embodiment, or to the peripheral sections 21c (see FIGS. 7A and 7B) of the individual retroreflectors 21-21 when the plurality of retroreflectors 21-21 are provided individually as described below.

[0041] Therefore, it is possible to make the viewer S easily perceive the aerial image AI as being displayed between the light branching unit 30 and the viewer S (particularly at the aerial display position P) rather than on the retroreflection unit 20.

[0042] 3A to 3D are schematic front views each showing a first to fourth mode of the moving device 50 of the display device 100 according to the first embodiment. FIG. 3E and FIG. 3F are side views each showing an example (501a) and another example (501b) of the vibration drive unit in the moving device 50 of the display device 100 according to the first embodiment. Note that FIG. 3E shows the first mode as a representative of the first to fourth modes of the moving device 50.

[0043] 4A and 4B are respectively a perspective view and a front view showing a first mode of the moving device 50 of the display device 100 according to the second embodiment. FIG. 4C and FIG. 4D are respectively a perspective view and a front view showing a second mode of the moving device 50 of the display device 100 according to the second embodiment. FIG. 4E and FIG. 4F are respectively a front view and a side view showing a third mode of the moving device 50 of the display device 100 according to the second embodiment. FIG. 4G is a front view showing a modified example of the third mode of the moving device 50 of the display device 100 according to the second embodiment. FIG. 4H and FIG. 4I are respectively a side view and a front view showing an example of a combination of the rotating device 52 and the vibrating device 51.

[0044] In this embodiment, joints 41 between adjacent retroreflectors 21, 21 in retroreflective section 20 are non-retroreflective sections 40.

[0045] The display device 100 includes a moving device 50 that moves the retroreflection unit 20 in a cross direction (in this example, a perpendicular direction, in the first embodiment, a first linear direction X, a second linear direction Y, and diagonal directions T1 and T2, and in the second embodiment, a rotational direction E) that crosses the optical axis direction K of the retroreflected light L2. The moving device 50 includes one or more movement drivers 501 (501a, 501b, 501c) that drive the retroreflection unit 20 to move.

[0046] In this way, by moving the retroreflective portion 20 in the intersecting direction [(X, Y, T1, T2), E], it is possible to reliably make it difficult for the viewer S to perceive the non-retroreflective portion 40 in the retroreflective portion 20. Therefore, it is possible to reliably make the viewer S perceive the aerial image AI as being displayed not by the retroreflective portion 20 but between the light branching portion 30 and the viewer S (particularly at the aerial display position P).

[0047] (First embodiment) As shown in Figures 3A to 3F, in the display device 100 of the first embodiment, the moving device 50 includes a vibration device 51 (an example of the moving device 50) that vibrates the retroreflective portion 20 in a reciprocating movement direction [X (X1, X2), Y (Y1, Y2), T1, T2] along the intersecting direction.

[0048] That is, the vibration device 51 of the first embodiment shown in FIG. 3A vibrates the retroreflective portion 20 in a first linear direction X (in this example, vertical directions X1 and X2) along an orthogonal direction perpendicular to the optical axis direction K of the retroreflected light L2. The vibration device 51 of the second embodiment shown in FIG. 3B vibrates the retroreflective portion 20 in a second linear direction Y (in this example, horizontal directions Y1 and Y2) along an orthogonal direction perpendicular to the optical axis direction K of the retroreflected light L2. The vibration device 51 of the third embodiment shown in FIG. 3C vibrates the retroreflective portion 20 in the first linear direction X (in this example, vertical directions X1 and X2) and in the second linear direction Y (in this example, horizontal directions Y1 and Y2). The vibration device 51 of the fourth embodiment shown in FIG. 3D vibrates the retroreflective portion 20 in the diagonal directions T1 and T2.

[0049] In this way, it is possible to easily realize the moving device 50 that moves the retroreflective portion 20 in the intersecting directions (X, Y, T1, T2) using a simple configuration such as the vibration device 51.

[0050] Specifically, the vibration device 51 includes one or more pairs (two pairs in this example) of biasing members (51a-51h) and vibration drive units 501a, 501b. The biasing members (51a-51h) bias the retroreflective unit 20 so that it can move in the reciprocating movement directions [X (X1, X2), Y (Y1, Y2), T1, T2]. In the first and third embodiments shown in Figs. 3A and 3C, the biasing members (51a, 51b) bias the retroreflective unit 20 so that it can move in the up-down directions X1, X2, and in this example, are elastic springs that expand and contract in the up-down directions X1, X2. In the second and third embodiments shown in Figs. 3B and 3C, the biasing members (51c, 51d) bias the retroreflective unit 20 so that it can move in the left-right directions Y1, Y2, and in this example, are elastic springs that expand and contract in the left-right directions Y1, Y2. In addition, in the fourth embodiment shown in FIG. 3D, the biasing members (51e, 51f), (51g, 51h) bias the retroreflective portion 20 to move in the diagonal directions T1, T2, and in this example are elastic springs that expand and contract in the diagonal directions T1, T2.

[0051] Specifically, one end of each of the biasing members (51a to 51h) is connected to the retroreflection portion 20, and the other end is connected to the display device main body 101 (main body frame).

[0052] As shown in Fig. 3E and Fig. 3F, the vibration drivers 501a and 501b act as the movement driver 501 and drive the retroreflective unit 20 to vibrate in the reciprocating movement directions [X (X1, X2), Y (Y1, Y2), T1, T2]. In a first mode shown in Fig. 3A, the vibration drivers 501a and 501b drive the retroreflective unit 20 to vibrate in the vertical directions X1 and X2. In a second mode shown in Fig. 3B, the vibration drivers 501a and 501b drive the retroreflective unit 20 to vibrate in the horizontal directions Y1 and Y2. In a third mode shown in Fig. 3C, the vibration drivers 501a and 501b drive the retroreflective unit 20 to vibrate in both the vertical directions X1 and X2 and the horizontal directions Y1 and Y2. 3D, the vibration drivers 501a and 501b drive the retroreflection unit 20 to vibrate in the oblique directions T1 and T2. The vibration drivers 501a and 501b have a drive unit main body 50a fixed to the display device main body 101 (main body frame). The retroreflection unit 20 is fixed to movable parts 501a1 and 501b1 of the vibration drivers 501a and 501b.

[0053] The vibration driving unit 501a is a power unit that is driven by the supply of electric power. Examples of the power unit include a vibration motor and an air vibrator. The vibration driving unit 501b is a driving element that is deformed by the supply of electric power. Examples of the driving element include a piezoelectric bending actuator. The piezoelectric bending actuator displaces the end portion on the retroreflective unit 20 side in the reciprocating movement direction [X (X1, X2), Y (Y1, Y2), T1, T2] due to the bending moment generated by the driving and contraction of the piezoelectric element.

[0054] In this example, the retroreflective portion 20 is moved in a direction intersecting the optical axis direction K of the retroreflected light L2, but the retroreflective portion 20 may be moved in the optical axis direction K of the retroreflected light L2.

[0055] Second embodiment In the second embodiment, the configurations that are substantially the same as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0056] As shown in Figures 4A to 4I, when displaying an aerial image AI, the display device 100 according to the second embodiment constantly moves the retroreflective section 20 within a range that maintains the retroreflective performance of the retroreflective section 20.

[0057] By doing this, the retroreflective section 20, which is made up of a plurality of retroreflective bodies 21-21, is constantly moving, and the non-retroreflective sections 40 (41) of the retroreflective bodies 21-21 can also constantly be moved, thereby making the non-retroreflective sections 40 (41) in the retroreflective section 20 even less noticeable to the viewer S.

[0058] This makes it easier for the viewer S to sense that the aerial image AI is being displayed between the light branching unit 30 and the viewer S (particularly at the aerial display position P) rather than on the retroreflecting unit 20 .

[0059] In the display device 100 of the second embodiment, the moving device 50 includes a rotation device 52 (another example of the moving device 50) that rotates the retroreflective portion 20 in a rotation direction E (in this example, a first rotation direction E1 and / or a second rotation direction E2) along the intersecting direction.

[0060] In this way, it is possible to easily realize the moving device 50 that moves the retroreflective portion 20 in the cross direction (E) using a simple configuration such as the rotation device 52.

[0061] More specifically, the rotation device 52 includes a rotation drive unit 501c (a drive motor in this example). The rotation drive unit 501c acts as a movement drive unit 501, and drives the retroreflection unit 20 to rotate in a rotation direction E, as shown in Figs. 4A to 4I. The rotation drive unit 501c has a drive unit main body 50a fixed to the display device main body 101 (main body frame).

[0062] In the rotating device 52 shown in Figures 4A to 4D, the retroreflective portion 20 is in the form of a sheet, and is formed in the form of an endless belt. The rotating device 52 shown in Figures 4A and 4B rotates the retroreflective portion 20 so that the belt-like retroreflective portion 20 moves in a circular motion. In this way, the retroreflective portion 20 can be rotated stably and reliably.

[0063] 4A and 4B, the retroreflective section 20 has joints 41 (40) between adjacent retroreflectors 21, 21 extending along the rotation axis direction N. In the rotation device 52 shown in FIGS. 4C and 4D, the retroreflective section 20 is composed of multiple (three in this example) retroreflectors 21-21 arranged side by side in the rotation axis direction N.

[0064] 4A to 4D includes a drive roller 521 and a driven roller 522. The drive roller 521 and the driven roller 522 are rotatably provided on the display device main body 101 (main body frame).

[0065] 4A and 4B, the retroreflection unit 20 is suspended between a drive roller 521 and a driven roller 522. The rotation drive unit 501c has a rotation shaft 501c1 fixed to the drive roller 521, and drives the drive roller 521 to rotate in a first rotation direction E1 (E). This allows the retroreflection unit 20 to rotate (move in a circle) in the first rotation direction E1 (E).

[0066] 4C and 4D, a plurality of retroreflectors 21-21 constituting the retroreflection section 20 are provided individually (independently). The display device 100 moves each of the plurality of retroreflectors 21-21.

[0067] In the rotating device 52 shown in Fig. 4C and Fig. 4D, the driving roller 521 and the driven roller 522 are each composed of a plurality of (three in this example) driving roller parts 521a to 521c and driven roller parts 522a to 522c arranged in parallel in the rotation axis direction N. In the rotation axis direction N, the retroreflector 21 at one end is suspended on the driving roller part 521a and the driven roller part 522a at one end, the retroreflector 21 at the center is suspended on the driving roller part 521b and the driven roller part 522b at the center, and the retroreflector 21 at the other end is suspended on the driving roller part 521c and the driven roller part 522c at the other end. Between the adjacent driving roller parts (521a, 521b), (521b, 521c), there are provided drive transmission mechanisms 521d, 521e (mechanisms including gears) that transmit rotational driving force so that the driving roller parts rotate in the opposite directions to each other. The rotation drive unit 501c has a rotation shaft 501c1 fixed to the drive roller unit 521a at one end in the rotation axis direction N, and drives the drive roller unit 521a at one end to rotate in a first rotation direction E1. In this way, when the drive roller unit 521a at one end is driven to rotate in the first rotation direction E1 in the rotation axis direction N, the drive roller unit 521b at the center can be rotated in the second rotation direction E2 by the drive transmission mechanism 521d, and the drive roller unit 521c at the other end can be rotated in the first rotation direction E1 by the drive transmission mechanism 521e. As a result, in the rotation axis direction N, the retroreflector 21 at one end can be rotated (moved around) in the first rotation direction E1, the retroreflector 21 at the center can be rotated in the second rotation direction E2, and the retroreflector 21 at the other end can be rotated in the first rotation direction E1.

[0068] In the rotation device 52 shown in Figures 4E to 4G, the retroreflective unit 20 is formed in a plate shape. The rotation device 52 shown in Figures 4E to 4G rotates the retroreflective unit 20 around a rotation axis α (rotation center) that passes through the plate-shaped retroreflective unit 20. In this way, the retroreflective unit 20 can be rotated stably and reliably.

[0069] 4E to 4G, a rotational drive unit 501c rotates the retroreflective unit 20 in a rotational direction E about a rotational axis α. The retroreflective unit 20 is fixed to a rotational axis 501c1 such that the rotational axis α is perpendicular or substantially perpendicular to the rotational axis 501c1 of the rotational drive unit 501c.

[0070] The display device 100 shown in Figures 4H and 4I is a combination of a rotation device 52 and a vibration device 51. More specifically, in the display device 100 shown in Figures 4H and 4I, the retroreflective unit 20 is fixed to a rotation shaft 501c1 via a vibration drive unit 501b so that the rotation axis α is perpendicular or approximately perpendicular to the rotation shaft 501c1 of the rotation drive unit 501c. In this way, the retroreflective unit 20 can be rotated in one direction (E) in the intersecting directions while being oscillated in other directions (X, Y, T1, T2) in the intersecting directions, which makes it even more difficult for the viewer S to see the non-retroreflective unit 40 (41) in the retroreflective unit 20.

[0071] In the second embodiment, the display device 100 rotates the rotation drive unit 501c in a first rotation direction E1, but may be configured to rotate the rotation drive unit 501c by alternately switching between the first rotation direction E1 and a second rotation direction E2 opposite to the first rotation direction E1.

[0072] The rotation drive unit 501c may be a DC motor, an AC motor, or a servo motor. Examples of the DC motor include a brush motor and a brushless motor, examples of the AC motor include a single-phase induction motor, a three-phase induction motor, and a three-phase synchronous motor, and examples of the servo motor include a stepping motor, a DC servo motor, and an AC servo motor.

[0073] Incidentally, when the retroreflective unit 20 is rotated, the circumferential speed (moving speed) of the retroreflective unit 20 slows down toward the rotation axis α in the radial direction W (see FIG. 4E) centered on the rotation axis α. Therefore, when a predetermined central region β centered on the rotation axis α of the retroreflective unit 20 is a region that rotates at a circumferential speed (moving speed) lower than a predetermined specified speed, if a seam 41 is provided in the central region β (see FIG. 4E), the seam 41 in the central region β can be easily seen by the viewer S. This makes it easier for the viewer S to sense that the aerial image AI is displayed on the retroreflective unit 20 in the central region β.

[0074] Therefore, in this embodiment, a predetermined central region β centered on the rotation axis α of the retroreflective portion 20 is a region that rotates at a circumferential speed (moving speed) that is lower than a predetermined specified speed, and it is preferable that no seam portion 41 is provided in the central region β.

[0075] 4G, the central region β does not have a joint portion 41. This makes it easier for the viewer S to feel that the aerial image AI is displayed between the light branching unit 30 and the viewer S (particularly at the aerial display position P) and not on the retroreflective unit 20 as a whole, including the central region β.

[0076] (Configuration essentially common to the first and second embodiments) FIG. 5 is a system block diagram showing a schematic configuration of a display system 200 including the display device 100 according to the first and second embodiments.

[0077] As shown in FIG. 5, the display system 200 includes a command unit 210 (command control device) and the display device 100.

[0078] The command unit 210 transmits command signals to the display device 100 and is provided in a command center. The command unit 210 transmits information related to the display contents to the display device 100 via communication means such as a wired and / or wireless communication network. The command unit 210 is capable of forcibly changing the display contents on the display device 100 in the event of an emergency such as a disaster, for example.

[0079] The display device 100 further includes a control unit 120 , a driver unit 130 , an environment sensor unit 140 , and an object sensor unit 150 .

[0080] The control unit 120 has a processing unit 120a consisting of a computer such as a CPU (Central Processing Unit), and a storage unit 120b including a non-volatile memory such as a ROM (Read Only Memory) and a volatile memory such as a RAM (Random Access Memory). The control unit 120 controls the operation of various components by the processing unit 120a loading a control program stored in advance in the ROM of the storage unit 120b onto the RAM of the storage unit 120b and executing it.

[0081] The display unit 110 includes a display device such as a liquid crystal display or an organic electroluminescence display. The display unit 110 is electrically connected to an output system of the control unit 120, and a display signal related to a display image IM is input from the control unit 120. This allows the display unit 110 to display the display image IM according to the display signal from the control unit 120.

[0082] The driver unit 130 is a drive control unit for driving the moving device 50 (51, 52). The driver unit 130 is electrically connected to an output system of the control unit 120, and receives an instruction signal from the control unit 120. This allows the driver unit 130 to drive the moving device 50 (51, 52) according to the instruction signal from the control unit 120.

[0083] The environment sensor unit 140 is electrically connected to an input system of the control unit 120, and transmits an environment signal indicating the environment, such as the brightness of the surroundings, to the control unit 120. This allows the control unit 120 to detect (recognize) the environment, such as the brightness of the surroundings, based on the environment signal from the environment sensor unit 140. However, if the surroundings are dark, it is not necessary to make the display unit 110 brighter than necessary. For this reason, for example, when the control unit 120 determines that the surroundings are darker than the reference brightness based on the environment signal from the environment sensor unit 140, it reduces the brightness (luminance) of the display unit 110.

[0084] The objective sensor unit 150 is electrically connected to an input system of the control unit 120, and transmits a detection signal to the control unit 120, which detects detection information such as the presence or absence of a viewer S or a moving body M such as a car carrying the viewer S. This allows the control unit 120 to detect (recognize) detection information such as the presence or absence of the moving body M from the detection signal from the objective sensor unit 150. However, if there is no viewer S, there is no need to display the display unit 110. For this reason, for example, when the control unit 120 determines that there is no moving body M (S) based on the detection signal from the objective sensor unit 150, it stops driving the display unit 110 and the moving device 50 (51, 52).

[0085] In addition, a function for detecting the speed of the moving object M may be added, and the movement of the retroreflective portion 20 may be changed according to the speed of the moving object M.

[0086] In the first and second embodiments, the moving device 50 may move the retroreflective portion 20 by a distance greater than the width d of the joint portion 41 (approximately 0.5 mm in this example) (see FIG. 2C).

[0087] This effectively makes it difficult for the viewer S to perceive the non-retroreflective portion 40 in the retroreflective portion 20. This makes it easier for the viewer S to perceive the aerial image AI as being displayed between the light branching portion 30 and the viewer S (particularly at the aerial display position P) rather than at the retroreflective portion 20.

[0088] In the first and second embodiments, the moving device 50 moves the retroreflection unit 20 at a moving speed equal to or higher than a predetermined specified speed via the driver unit 130 in response to an instruction signal from the control unit 120.

[0089] This effectively makes it difficult for the viewer S to perceive the non-retroreflective portion 40 in the retroreflective portion 20. This makes it easier for the viewer S to perceive the aerial image AI as being displayed between the light branching portion 30 and the viewer S (particularly at the aerial display position P) rather than at the retroreflective portion 20.

[0090] In the first and second embodiments, the specified speed is 780 times / sec the width d (e.g., 5 mm) of the joint 41 [e.g., (movement speed of the retroreflective section 20=3.9 m / sec) / (width d of the joint 41=5 mm)]. For example, when the speed of the moving body M is 0 km / h to 40 km / h, 780 times / sec the width d of the joint 41 can be exemplified, and when the speed of the moving body M is 60 km / h to 120 km / h, it can be faster (or slower) than this.

[0091] In this way, by having the moving device 50 move the retroreflective portion 20 at a moving speed of at least 780 times the width d (e.g., 5 mm) of the joint portion 41 per second [e.g., (3.9 m / sec) / (5 mm)], it is possible to more effectively make it difficult for the viewer S to perceive the non-retroreflective portion 40 in the retroreflective portion 20. This makes it possible to make the viewer S more easily perceive the aerial image AI as being displayed not on the retroreflective portion 20 but between the light branching portion 30 and the viewer S (particularly at the aerial display position P).

[0092] Here, in the moving device 50, the faster the moving speed of the retroreflection unit 20 is, the more the power consumption can be reduced, and the more energy saving can be realized. This will be described below by taking the display device 100 according to the second embodiment as an example.

[0093] Fig. 6A is a graph showing an example of the relationship between the rotation speed of a DC motor used as the rotary drive unit 501c in the display device 100 according to the second embodiment and the energy supplied to the DC motor. Fig. 6B is a circuit diagram showing the basic configuration of a drive circuit that drives the DC motor.

[0094] For example, when a DC motor is used as the rotary drive unit 501c that rotates the retroreflective unit 20, as shown in Fig. 6A, when the input voltage is constant, the input current of the DC motor decreases, that is, the power consumption decreases, as the number of rotations per unit time (the peripheral speed (movement speed) of the retroreflective unit 20) increases (the load torque decreases), as shown in Fig. 6B. Moreover, when the rated voltage is V, the electrical resistance is R, the moment of inertia is J, and the initial value of the angular velocity is ω, 0 Then, the relation between the angular velocity ω of the DC motor and the input current I is V×I=R×I 2 +〔J×(ω 2 -ω 0 2 ) / 2. From this formula, the energy (V × I) supplied to the DC motor can be reduced in power consumption as the angular velocity ω (the peripheral speed (moving speed) of the retroreflective portion 20) of the DC motor is increased.

[0095] Third embodiment 7A, 7B, and 7C are side views respectively showing an example in which a plurality of retroreflectors 21-21 are provided individually in a display device 100 according to the third embodiment, another example, and yet another example.

[0096] In the third embodiment, the configurations that are substantially the same as those in the first and second embodiments are denoted by the same reference numerals, and the description thereof will be omitted.

[0097] 7A to 7C, in a display device 100 according to the third embodiment, a plurality of retroreflectors 21-21 constituting a retroreflection section 20 are provided separately (individually independent). The display device 100 includes a plurality of moving devices 50-50. The plurality of moving devices 50-50 move the plurality of retroreflectors 21-21, respectively.

[0098] In this way, the individual retroreflectors 21, ..., 21 can be moved by the multiple moving devices 50-50, thereby making it difficult for the viewer S to notice the non-retroreflecting portions 40 in the retroreflecting portion 20. This makes it easier for the viewer S to sense that the aerial image AI is displayed between the light branching portion 30 and the viewer S (particularly at the aerial display position P) rather than at the retroreflecting portion 20.

[0099] In the display device 100 according to the third embodiment, for example, the moving devices 50-50 include a rotation device 52 as shown in Fig. 4F. In the moving devices 50-50, the drive unit main body 50a is fixed to the display device main body 101 (main body frame) via support members 50b-50b. Note that, although the moving devices 50-50 include the rotation device 52 in this example, they may include a vibration device 51 as shown in Fig. 3F instead of or in addition to the rotation device 52.

[0100] 7A, the retroreflective section 20 is configured such that adjacent retroreflectors 21, 21 overlap each other when viewed from a plane (optical axis direction K of retroreflected light L2) (in orthogonal directions (X, Y, T1, T2) perpendicular to the optical axis direction K) when the individual retroreflectors 21, 21 are moving. Note that when the individual retroreflectors 21, 21 are stationary, none of the multiple retroreflectors 21, 21 may overlap, or at least two retroreflectors 21, 21 may overlap.

[0101] In this way, by overlapping adjacent retroreflectors 21 while each retroreflector 21 is moving, it is possible to make the non-retroreflecting portion 40 (peripheral portion 21c) in the retroreflecting portion 20 even less noticeable to the viewer S. This makes it easier for the viewer to sense that the aerial image AI is displayed between the light branching portion 30 and the viewer (particularly at the aerial display position P) rather than at the retroreflecting portion 20.

[0102] Note that the present invention is not limited to the example shown in Figure 7A, and as in the examples shown in Figures 7B and 7C, the retroreflective section 20 may be configured so that adjacent retroreflectors 21, 21 do not overlap when viewed from a plane (in the optical axis direction K of the retroreflected light L2) when each individual retroreflector 21-21 is moving.

[0103] In the example shown in FIGS. 7A and 7B, the retroreflective portion 20 is configured such that a plurality of retroreflectors 21 are alternately arranged in the optical axis direction K of the retroreflected light L2.

[0104] In this way, the retroreflector 21 and the moving device 50 can be positioned alternately at the same positions in the optical axis direction K of the retroreflected light L2, thereby simplifying the configuration for arranging multiple moving devices 50-50 in the display device 100.

[0105] Note that the present invention is not limited to the examples shown in Figures 7A and 7B, and as in the example shown in Figure 7C, the retroreflective section 20 may be configured such that none of the multiple retroreflectors 21-21 are aligned in the optical axis direction K of the retroreflected light L2.

[0106] [Experimental Example] Next, an evaluation experiment was carried out on the display device 100 according to the second embodiment, and the details thereof will be described below.

[0107] That is, in this experimental example, seven subjects (viewers S) were investigated as to whether the aerial image AI appeared to be displayed at an aerial display position P between the optical branching unit 30 and the viewer S (appeared to be floating), or whether it appeared to be displayed on the retroreflective unit 20 (not appeared to be floating).

[0108] (Configuration of display device 100) The display device 100 shown in Figs. 4E and 4F was used, and the light branching section 30 was a beam splitter made of a glass material with a thickness of 5 mm, a size of 1800 mm x 900 mm, and a refractive index of 1.52.

[0109] As the retroreflective section 20, 28 retroreflectors (retroreflective elements) of 500 mm square were attached to an acrylic plate that was the base material 22. In the experimental examples and the reference example, the retroreflective section 20 configured as follows was used.

[0110] Experimental example: A retroreflective portion 20 with a width d of 5 mm at the joint 41 was used.

[0111] Reference Example: A retroreflective portion was used in which eight pieces of tape, each 15 mm wide, were attached radially from the rotation axis α to the surface of the retroreflective portion 20, the width d of the joints 41 of which was 0.5 mm.

[0112] (Experimental conditions) The subjects (S) were asked to view the aerial image AI from observation positions 10 m and 15 m away from the aerial display position P.

[0113] A DC motor was used as the rotary drive unit 501c, and the number of rotations per unit time of the rotary drive unit 501c was increased in increments of 50 rpm up to 300 rpm (revolutions per minute).

[0114] FIG. 8 is a chart showing the rotation speed "rpm", the moving speed (m / sec) and the frequency (Hz). In FIG. 8, the rotation speed "rpm" represents the number of rotations per minute of the rotation drive unit 501c. The moving speed (m / sec) represents the circumferential speed at a position that is a predetermined distance of 250 mm away from the rotation axis α of the retroreflective unit 20 in the radial direction. If the moving speed (m / sec) is B, the distance is r, and the rotation speed "rpm" is A, then the moving speed (m / sec) B can be expressed as B [m / sec] = 2 × π × r × A [rpm] ÷ 60. Furthermore, the frequency (Hz) represents the frequency (= 1 / A) of the drive signal to the rotation drive unit 501c.

[0115] (Evaluation Results) Figures 9A and 9B are diagrams and graphs showing evaluation results 1-1 (magnification / second) in the experimental example, and Figures 9C and 9D are diagrams and graphs showing evaluation results 1-2 (movement speed) in the experimental example. Also, Figures 10A and 10B are diagrams and graphs showing evaluation results 2-1 (magnification / second) in the reference example, and Figures 10C and 10D are diagrams and graphs showing evaluation results 2-2 (movement speed) in the reference example.

[0116] In Figures 9A to 10D, among the seven subjects (S), the ratio (evaluation ratio) of those who answered that the aerial image AI appeared to be displayed at the aerial display position P between the optical branching unit 30 and the viewer S was 80% or more, which was rated as a good level "O", 30% or more but less than 80% was rated as an acceptable level "△", and 0% or more but less than 30% was rated as an unacceptable level "X".

[0117] 9A and 9B and 10A and 10B, the "magnification / sec relative to width d of seam 41" is calculated using the formula [movement speed (m / s) of retroreflective portion 20] / [width d (m) of seam 41].

[0118] In addition, in the graphs shown in FIGS. 10A and 10C, the shaded areas indicate changes with respect to the evaluations in the graphs shown in FIGS. 9A and 9C, respectively.

[0119] <Experimental Example> As shown in Figures 9A and 9B (Figures 9C and 9D), in the evaluation results 1-1 (1-2) of the experimental example, the viewer S began to feel that the aerial image AI appeared to be displayed at the aerial display position P when the magnification per unit second with respect to the width d of the seam 41 was 780 times (the width d of the seam 41 was 5 mm, and the moving speed of the retroreflective part 20 was 3.9 m / sec), and more than 80% of the viewers S felt that the aerial image AI appeared to be displayed at the aerial display position P when the magnification per unit second with respect to the width d of the seam 41 was 1300 times or more (the width d of the seam 41 was 5 mm, and the moving speed of the retroreflective part 20 was 6.5 m / sec) or more.

[0120] It was also found that the farther the observation position of the viewer S is from the aerial display position P, the more likely the viewer S is to feel that the aerial image AI is being displayed at the aerial display position P.

[0121] <Reference example> As shown in Figures 10B and 10B (Figures 10C and 10D), in the evaluation results 2-1 (2-2) of the reference example, it was found that as the width d of the seam 41 increases, the magnification ratio [(movement speed of the retroreflective portion 20) / (width d of the seam 41)] for the width d of the seam 41 per unit second needs to be increased.

[0122] The present invention is not limited to the above-described embodiment, but can be embodied in various other forms. Therefore, the embodiment is merely illustrative in all respects and should not be interpreted as being restrictive. The scope of the present invention is defined by the claims, and is not limited in any way by the text of the specification. Furthermore, all modifications and changes within the scope of the claims are within the scope of the present invention. [Explanation of symbols]

[0123] 10 light source 100 display device 101 Display device body 110 Display section 111 Display surface 120 Control section 120a Processing section 120b Storage section 130 Driver section 140 Environmental Sensor Section 150 Object sensor part 20 Retroreflective section 200 Display System 20a Retroreflective structure 20b Retroreflective structure 21 Retroreflector 210 Command Department 21a Retroreflective surface 21a1 Slope 21a2 Slope 21b Retroreflective surface 21b1 Curved surface 21c Periphery 22 Base material 30 Optical branching section 40 Non-retroreflective section 41 Joint 50 Mobile Device 501 Mobile drive unit 501a Vibration drive unit 501a1 Moving parts 501b Vibration drive unit 501b1 Moving parts 501c Rotation drive unit 501c1 Rotating shaft 50a Drive unit body 50b Support member 51 Vibration device 52 Rotating device 521 Drive roller 521a Drive roller section 521b Drive roller part 521c Drive roller part 521d Drive transmission mechanism 521e Drive transmission mechanism 522 Driven roller 522a Driven roller part 522b Driven roller part 522c Driven roller part AI aerial image AN Non-image section E Rotation direction E1 First rotation direction E2 Second rotation direction F plane direction I Current value IM Display Image K Optical axis direction L1 output light L2 Retroreflective light L3 reflected light L4 transmitted light La incident light Lb reflected light M Mobile object N Rotational axis direction P Aerial display position S. Viewer T1 Diagonal T2 Diagonal W Radiation direction X 1st linear direction (vertical direction) Y 2nd linear direction (left / right direction) α Rotation axis β central region ω angular velocity

Claims

1. A display device that displays an aerial image in a space, the display device comprising: a light source; a retroreflector; and a light branching unit that reflects or transmits light emitted from the light source toward the retroreflector and transmits or reflects retroreflected light reflected from the retroreflector, The retroreflective portion is composed of a plurality of retroreflectors, a display device configured to move the retroreflective portion within a range in which the retroreflective portion maintains its retroreflective performance when displaying the aerial image.

2. The display device according to claim 1 , a display device that, when displaying the aerial image, constantly moves the retroreflective portion within a range in which the retroreflective portion maintains its retroreflective performance.

3. The display device according to claim 1 or 2, The retroreflective portion is formed by connecting the plurality of retroreflectors, A joint portion between adjacent retroreflectors in the retroreflective portion is a non-retroreflective portion, The display device is characterized in that it includes a moving device that moves the retroreflective portion in a cross direction that crosses the optical axis direction of the retroreflected light.

4. The display device according to claim 3 , The display device, characterized in that the moving device includes a rotation device that rotates the retroreflective portion in a rotation direction along the intersecting direction.

5. The display device according to claim 3 , The retroreflective portion is formed in an endless belt shape, The display device, wherein the rotating device rotates the belt-shaped retroreflective portion so that the belt-shaped retroreflective portion moves in a circular motion.

6. The display device according to claim 3 , The retroreflective portion is formed in a plate shape, The display device, characterized in that the rotation device rotates the retroreflective portion around a rotation axis passing through the plate-shaped retroreflective portion.

7. The display device according to claim 6, A display device characterized in that a predetermined central region centered on the rotation axis of the retroreflective portion is a region that rotates at a peripheral speed lower than a predetermined specified speed, and the seam portion is not provided in the central region.

8. The display device according to claim 3 , The display device is characterized in that the moving device moves the retroreflective portion by a distance greater than the width of the joint portion.

9. The display device according to claim 3 , The display device is characterized in that the moving device moves the retroreflective portion at a moving speed equal to or higher than a predetermined specified speed.

10. The display device according to claim 9 , The display device according to claim 1, wherein the specified speed is 780 times the width of the seam per second.

11. The display device according to claim 1 or 2, The plurality of retroreflectors constituting the retroreflective portion are provided individually, A display device comprising: a display unit configured to move each of the plurality of retroreflectors.

12. The display device according to claim 11, The display device according to the present invention is characterized in that the retroreflective section is configured such that adjacent retroreflectors overlap in a plan view when each of the retroreflectors is moving.

13. The display device according to claim 12, The display device, characterized in that the retroreflective portion is configured such that the plurality of retroreflectors are alternately aligned in the optical axis direction of the retroreflected light.

Images