Aerial display device

Abstract

To provide an aerial display device in which the appearance of an aerial image is improved.SOLUTION: An aerial display device according to an embodiment includes a substrate and a retroreflective sheet. The plurality of light sources are two dimensionally arranged on the substrate. The retroreflective sheet is disposed on an emission side of the plurality of light sources and has a plurality of through holes corresponding to the plurality of light sources. A center position of each of the plurality of light sources is offset with respect to the through hole corresponding to each of the plurality of light sources according to a viewpoint position.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an aerial display device. [Background technology]

[0002] Conventionally, aerial display devices have been proposed that use retroreflective sheets and half mirrors to form images in the air (see, for example, Patent Documents 1 and 2). For example, a technology is known in which a retroreflective sheet having a plurality of through-holes arranged in a grid pattern and a light source corresponding to each through-hole are provided, and an aerial image of a desired shape is formed by locally emitting light according to the figure (characters, symbols, etc.) to be displayed in the air. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-81138 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-107165 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with conventional aerial display devices, it is difficult to obtain sufficient brightness, and there is room for improvement in the appearance of the aerial image.

[0005] The present invention has been made in consideration of the above, and aims to provide an aerial display device that improves the appearance of aerial images. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, an aerial display device according to one embodiment of the present invention comprises a substrate and a retroreflective sheet. A plurality of light sources are arranged two-dimensionally on the substrate. The retroreflective sheet is disposed on the output side of the plurality of light sources, and has a plurality of through-holes corresponding to the plurality of light sources. The center position of each of the plurality of light sources is offset from the through-hole corresponding to each of the plurality of light sources depending on the viewpoint position.

[0007] An aerial display device according to one aspect of the present invention can improve the appearance of an aerial image. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of an aerial display device according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line XX in FIG. [Figure 3] FIG. 3 is a diagram for explaining the positional relationship between the light source and the through-hole according to the embodiment. [Figure 4] FIG. 4 is a diagram for explaining the positional relationship between the light source and the through-hole according to the comparative example. [Figure 5A] FIG. 5A is a diagram for explaining color separation. [Figure 5B] FIG. 5B is a diagram for explaining color separation. [Figure 6] FIG. 6 is a diagram showing the position of the eyepoint (EP) relative to the aerial display device. [Figure 7] FIG. 7 is a diagram showing the change in luminance at different evaluation angles. [Figure 8A] FIG. 8A is a diagram showing changes in chromaticity at different evaluation angles. [Figure 8B] FIG. 8B is a diagram showing the change in chromaticity at different evaluation angles. [Figure 8C] FIG. 8C is a diagram showing the change in chromaticity at different evaluation angles. [Figure 9A] FIG. 9A is a diagram showing the change in chromaticity at different evaluation angles. [Figure 9B] FIG. 9B is a diagram showing the change in chromaticity at different evaluation angles. [Figure 9C] FIG. 9C is a diagram showing the change in chromaticity at different evaluation angles. [Figure 10] FIG. 10 is a diagram showing an example of the configuration of an aerial display device according to the first modification. [Figure 11] FIG. 11 is a diagram showing the change in luminance at different evaluation angles. [Figure 12A] FIG. 12A is a diagram showing changes in chromaticity at different evaluation angles. [Figure 12B] FIG. 12B is a diagram showing the change in chromaticity at different evaluation angles. [Figure 12C] FIG. 12C is a diagram showing the change in chromaticity at different evaluation angles. [Figure 13A] FIG. 13A is a diagram showing changes in chromaticity at different evaluation angles. [Figure 13B] FIG. 13B is a diagram showing the change in chromaticity at different evaluation angles. [Figure 13C] FIG. 13C is a diagram showing the change in chromaticity at different evaluation angles. [Figure 14] FIG. 14 is a diagram showing an example of the configuration of an aerial display device according to the second modification. [Figure 15] FIG. 15 is a diagram showing a configuration example of an aerial display device according to the third modification. [Figure 16] FIG. 16 is a diagram for explaining a method for determining the offset amount. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an aerial display device according to an embodiment will be described with reference to the drawings. Note that this embodiment does not limit the present invention. Furthermore, the dimensional relationships and ratios of each element in the drawings may differ from reality. Even between drawings, there may be parts in which the dimensional relationships and ratios differ. Furthermore, the content described in one embodiment or variant applies, in principle, to other embodiments or variants as well.

[0010] (Embodiment) FIG. 1 is a diagram showing an example of the configuration of an aerial display device 1 according to an embodiment. FIG. 1 illustrates a view from the display surface side. FIG. 2 is a cross-sectional view taken along line XX in FIG. 1. The aerial display device 1 is intended for use in an operation panel installed on a wall or the like in a private toilet, with the display surface facing horizontally (the display surface is installed in a vertical plane), and the eyepoint (viewpoint position) set in a direction tilted, for example, by 25 degrees in the negative Y-axis direction from the normal direction of the display surface (see FIG. 6 described below). Note that the use of the aerial display device 1 is not limited to operation panels for private toilets, etc.

[0011] 1 and 2, the aerial display device 1 includes a frame 2, a substrate 3, a light source 4, a polarized reflective sheet 5, a retroreflective sheet 6, a retardation film 7, a polarized reflective sheet 8, and a top cover 9.

[0012] The frame 2 is a substantially box-shaped member with a bottom, and accommodates a substrate 3 (described later) and the like in a substantially rectangular recess 2a. The substrate 3 is provided on the bottom surface of the recess 2a and is a member that includes electronic components such as a light source 4 (described later).

[0013] The light sources 4 are configured with LEDs (Light Emitting Diodes) or the like, and include, for example, three types (RGB) of LED chips. A plurality of light sources 4 are provided on the substrate 3 in a two-dimensional (for example, lattice) pattern, and are arranged at positions corresponding to a plurality of through-holes 6a formed in the retroreflective sheet 6, which will be described later. Each light source 4 is driven individually. Note that the light sources 4 are not limited to RGB-LEDs, and any light source can be used.

[0014] The polarizing reflective sheet 5 is disposed on the output side of the multiple light sources 4, that is, between the multiple light sources 4 and a retroreflective sheet 6 described below. The polarizing reflective sheet 5 is sufficient if it is large enough to cover the through holes 6a of the retroreflective sheet 6, but it may also be large enough to cover the entire surface of the retroreflective sheet 6.

[0015] The retroreflective sheet 6 is an optical component placed on the output side of the polarized reflective sheet 5, and has the property of reflecting incident light in the opposite direction along approximately the same path. The retroreflective sheet 6 can be a corner cube, which is made up of three light-reflecting surfaces joined at right angles to each other, forming the inner surfaces of the vertices of a cube. While this is slightly more expensive, it offers the advantages of high light utilization efficiency and reduced blurring of the aerial display (aerial image). Alternatively, a retroreflective sheet 5 made of tiny transparent glass beads tightly arranged on the surface can also be used. This is less expensive, but has inferior performance.

[0016] The retroreflective sheet 6 is provided with a plurality of through holes 6a arranged in a grid pattern. Each through hole 6a corresponds to a light source 4, and typically, one through hole 6a is provided on the emission side of each light source 4. With this configuration, a desired aerial image can be formed by locally illuminating the plurality of light sources 4 according to the graphic (characters, symbols, etc.) to be displayed in the air. Note that the number of through holes 6a for each light source 4 is not limited to one, and there may be multiple. The positional relationship between the light sources 4 and the through holes 6 will be described in detail later.

[0017] The retardation film 7 is disposed on the exit side of the retroreflective sheet 6, and has through-holes 7a of the same shape and at the same positions as the through-holes 6a of the retroreflective sheet 6. For example, the through-holes 6a and 7a are formed simultaneously after the retardation film 7 is attached to the retroreflective sheet 6. The retardation of the retardation film 7 is λ / 4, and the delay axis in the XY plane is tilted 45° in the positive or negative direction with respect to the polarization axis of the incident light (the reflection axis or transmission axis of the polarized reflective sheet 8 described below; since the reflection axis and transmission axis are basically arranged horizontally or vertically, this results in the X axis or Y axis). The through-holes 6a and 7a are collectively referred to as "through-holes 6a, 7a."

[0018] The polarizing reflective sheet 8 functions as a beam splitter and is disposed on the exit side of the retardation film 7. The polarizing reflective sheet 8 is disposed so that its transmission axis (the direction of polarized light to be passed) is perpendicular to the polarizing reflective sheet 5.

[0019] The top cover 9 is made of a transparent material and is intended to protect the polarized reflective sheet 8 and the internal configuration of the frame 2. The outer surface (viewing side) of the top cover 9 is preferably hard coated to prevent scratches, stains, and provide antibacterial properties.

[0020] Note that the descriptions in FIGS. 1 and 2 are merely examples, and the embodiment is not limited thereto. For example, although FIGS. 1 and 2 illustrate a configuration using a polarizing reflective sheet 5, a retardation film 7, and a polarizing reflective sheet 8, the embodiment is not limited thereto. For example, a configuration using a half mirror instead of the polarizing reflective sheet 8 may be used. In this case, the half mirror functions as a beam splitter and is disposed at the position of the polarizing reflective sheet 8, making the polarizing reflective sheet 5 and the retardation film 7 unnecessary. Furthermore, in a configuration using a half mirror, a louver sheet may be disposed at a position corresponding to the polarizing reflective sheet 5. Furthermore, in a configuration using a half mirror, it is preferable to separately provide a structure for suppressing light that is emitted from the top cover 9 without passing through the retroreflective sheet 6.

[0021] FIG. 3 is a diagram for explaining the positional relationship between the light source 4 and the through-hole 6 according to the embodiment. The front view of FIG. 3 corresponds to a view of the retardation film 7 as seen from the emission surface side of the aerial display device 1, and the cross-sectional view corresponds to the cross-sectional view taken along line XX in the front view. In FIG. 3, the center position P1 corresponds to the center position of the light source 4 (the center of gravity of the multiple LED chips), and the center position P2 corresponds to the center position of the through-hole 6a. Note that for convenience of illustrating the center position P1, the three LED chips 4a, 4b, and 4c included in the light source 4 are partially omitted from the illustration. Furthermore, the illustrated dimensions are merely examples and are not limited thereto.

[0022] As shown in Fig. 3, the light source 4 has three LED chips 4a, 4b, and 4c, which are arranged in order along the Y-axis direction. The three LED chips 4a, 4b, and 4c have different wavelengths and correspond to, for example, blue (B), green (G), and red (R) LED chips, respectively. The length of the light source 4 along the Y-axis is 2.1 mm. As shown in Fig. 6, the eyepoint is set in a direction tilted 25 degrees in the negative direction of the Y-axis from the normal to the display surface (retroreflective sheet 6).

[0023] Each of the through holes 6a, 7a has a shape extending in substantially the same direction as the arrangement direction of the three LED chips 4a, 4b, and 4c. For example, each of the through holes 6a, 7a has an elliptical shape with a length in the Y-axis direction of 2.2 mm and a length in the X-axis direction of 2 mm in a front view (XY plane). This allows light from each of the three LED chips 4a, 4b, and 4c arranged in one direction to be emitted from the through holes 6a, 7a with as little leakage as possible, thereby improving brightness. Note that the shape of each of the through holes 6a, 7a is not limited to an ellipse, and may be a rectangle or a polygon.

[0024] Here, the center position P1 of each light source 4 is offset with respect to the through-hole 6a corresponding to that light source 4 in accordance with the eyepoint. Specifically, the center position P1 of each light source 4 is offset in approximately the same direction as the eyepoint's inclination with respect to the normal to the retroreflective sheeting 6. In the example of FIG. 3, the eyepoint is set in a direction inclined 25 degrees in the negative Y-axis direction from the normal to the retroreflective sheeting 6. In this case, the center position P1 of each light source 4 is offset, for example, by 0.3 mm in the negative Y-axis direction with respect to the center position P2 of each through-hole 6a corresponding to that light source 4. This can reduce color separation, which will be described later, and improve the appearance of the aerial image.

[0025] Note that the content described in Fig. 3 is merely an example, and the embodiment is not limited thereto. For example, as shown in Fig. 3, the three LED chips 4a, 4b, and 4c are not necessarily arranged in a straight line, but when multiple LED chips are included, the arrangement direction can be generally determined. For example, the direction of the approximate straight line of the multiple LED chips in the XY plane can be set as the arrangement direction of the multiple LED chips.

[0026] Furthermore, "substantially the same direction" is not limited to the same direction without any difference, but is intended to allow for some deviation within a range that does not lose the effect.

[0027] FIG. 4 is a diagram illustrating the positional relationship between the light source 4 and the through-hole 6 in the comparative example. The front view of FIG. 4 corresponds to a view of the retardation film 7' viewed from the emission surface side of the aerial display device 1, and the cross-sectional view corresponds to the cross-sectional view taken along line XX in the front view. In FIG. 4, the center position P3 corresponds to the center position of the light source 4', and the center position P4 corresponds to the center position of the through-hole 6a'. Note that for convenience of illustrating the center position P3, the three LED chips 4a', 4b', and 4c' included in the light source 4' are partially omitted from the illustration. Furthermore, the illustrated dimensions are merely examples and are not limited thereto.

[0028] The configuration of the aerial display device according to the comparative example is basically the same as that shown in FIGS. 1 and 2, except for the content described in FIG. 4, and therefore description thereof will be omitted.

[0029] 4, the light source 4' has basically the same configuration as the light source 4, and includes three LED chips 4a', 4b', and 4c'. The three LED chips 4a', 4b', and 4c' correspond to, for example, blue (B), green (G), and red (R) LED chips, respectively.

[0030] Here, in the front view, each of the through holes 6a', 7a' is not elliptical but has a perfect circular shape with a diameter of 2 mm. Furthermore, the center position P3 of each light source 4 is not offset from the center position P4 of each through hole 6a corresponding to each light source 4, and is in the same position in the front view.

[0031] The "color separation" will be explained using the configuration of an aerial display device according to a comparative example. Figures 5A and 5B are diagrams for explaining the color separation. Figure 5A illustrates an example in which the eyepoint is located near the front of the light source 4', and Figure 5B illustrates an example in which the eyepoint is located in a diagonal direction (negative Y-axis direction).

[0032] For example, at the eyepoint in Figure 5A, all light from the three LED chips 4a', 4b', and 4c' reaches the eyepoint, so white light is seen. On the other hand, at the eyepoint in Figure 5B, only blue light from LED chip 4a' reaches the eyepoint, while light from LED chips 4b' and 4c' is blocked by the retroreflective sheet 6' and retardation film 7' and does not reach the eyepoint. As a result, blue light is seen at the eyepoint in Figure 5B. This phenomenon, in which light from some of the three LED chips 4a', 4b', and 4c' does not reach the eyepoint depending on the position of the eyepoint, is called "color separation."

[0033] Fig. 6 is a diagram showing the position of the eye point (EP) for the aerial display device 1. As shown in Fig. 6, the eye point is set in a direction tilted, for example, by 25 degrees in the negative Y-axis direction from the normal direction of the display surface.

[0034] 6 shows an example in which the aerial display device 1 is placed vertically, but the same applies when it is placed flat. That is, the relative relationship between the tilt direction and offset direction of the eyepoint, and the relative relationship between the arrangement direction of the LED chips and the extension direction of the through-holes do not change whether it is placed vertically or flat.

[0035] Figure 7 shows the change in brightness at different evaluation angles. As shown in Figure 7, at an evaluation angle of 15 degrees, which is close to the front direction, the comparative example is slightly brighter than the embodiment (aerial display device 1), but the brightness of the embodiment becomes higher as the evaluation angle increases. As a result, it was found that the aerial display device 1 according to the embodiment has high brightness at the main evaluation angle, improving the appearance of the aerial image.

[0036] Figures 8A, 8B, 8C, 9A, 9B, and 9C show changes in chromaticity at different evaluation angles. Figures 8A, 8B, and 8C show the values ​​of chromaticity x, chromaticity y, and chromaticity z (=1-xy), respectively. Figures 9A, 9B, and 9C show the chromaticity ratios for each evaluation angle, assuming that the chromaticity at an evaluation angle of 25 degrees is 1. As shown in Figures 8A to 9C, the embodiment exhibited smaller changes in chromaticity depending on the evaluation angle than the comparative example. As a result, it was found that the aerial display device 1 according to the embodiment reduced color separation and improved the appearance of the aerial image.

[0037] (Variation 1) For example, the aerial display device 1 may include a diffuser plate between the substrate 3 and the retroreflective sheet 6 to further reduce color separation.

[0038] Fig. 10 is a diagram showing an example of the configuration of an aerial display device 1 according to Modification 1. The front view of Fig. 10 corresponds to a view of the retardation film 7 seen from the emission surface side of the aerial display device 1, and the cross-sectional view corresponds to the XX cross-sectional view in the front view. Note that the configuration of the aerial display device 1 according to Modification 1 is basically the same as that shown in Figs. 1 to 3, except that it is provided with a diffusion plate 10, and therefore, explanation will be omitted where appropriate.

[0039] As shown in Fig. 10, the aerial display device 1 according to the first modification includes a diffuser plate 10 between the substrate 3 and the retroreflective sheet 6. The diffuser plate 10 diffuses the light from the light source 4 to make the light uniform. For example, ML-3500ZA (manufactured by Teijin Ltd.) is used as the diffuser plate 10.

[0040] Fig. 11 is a diagram showing the change in luminance at different evaluation angles. As shown in Fig. 11, although the luminance of Modification 1 is lower than that of the configuration of the embodiment, the change in chromaticity is reduced. As a result, it was found that the aerial display device 1 according to Modification 1 improves the appearance of the aerial image.

[0041] Figures 12A, 12B, 12C, 13A, 13B, and 13C show changes in chromaticity at different evaluation angles. Figures 12A, 12B, and 12C show the values ​​of chromaticity x, chromaticity y, and chromaticity z, respectively. Figures 13A, 13B, and 13C show the chromaticity ratios for each evaluation angle, with the chromaticity at an evaluation angle of 25 degrees set to 1. As shown in Figures 12A to 13C, the change in chromaticity according to the evaluation angle was smaller in Variation 1 than in the embodiment. As a result, it was found that the aerial display device 1 according to Variation 1 reduces color separation and improves the appearance of the aerial image.

[0042] (Variation 2) Furthermore, for example, the aerial display device 1 may be provided with a plurality of through holes for one light source 4 in order to improve the appearance of the aerial image when viewed from the front.

[0043] For example, it is known that as the size of the through holes in the retroreflective sheet 6 increases, the amount of missing information in the aerial image increases when viewed from the front. Therefore, the aerial display device 1 according to variant 2 reduces the size of the through holes in the retroreflective sheet 6 and provides a predetermined number of through holes for each light source 4, thereby reducing the amount of missing information in the aerial image even when viewed from the front without reducing resolution.

[0044] Fig. 14 is a diagram showing an example of the configuration of the aerial display device 1 according to Modification 2. The front view of Fig. 14 corresponds to a view of the retardation film 7 seen from the exit surface side of the aerial display device 1, and the cross-sectional view corresponds to the XX cross-sectional view in the front view. Note that the configuration of the aerial display device 1 according to Modification 2 is basically the same as that shown in Figs. 1, 2, and 10, except for the content explained in Fig. 14, and therefore the explanation will be omitted as appropriate.

[0045] As shown in Fig. 14, the aerial display device 1 according to the second modification includes a retroreflective sheet 11 and a retardation film 12 instead of the retroreflective sheet 6 and the retardation film 7. The retroreflective sheet 11 is basically the same as the retroreflective sheet 6 except that it has through-holes 11a that are smaller than the through-holes 6a. The retardation film 12 is basically the same as the retardation film 7 except that it has through-holes 12a that are smaller than the through-holes 7a.

[0046] Here, the four through-holes 11a, 12a included in region R are located on the emission side of one light source 4. The center position P1 of this light source 4 is offset, for example, by 0.3 mm in the negative Y-axis direction from the center position P5 of the four through-holes 11a, 12a included in region R. This makes it possible to reduce chipping of the aerial image even when viewed from the front, improving the appearance of the aerial image.

[0047] When a predetermined number of through holes 11a, 12a are arranged for one light source 4, the number of through holes 11a, 12a can be set arbitrarily. However, considering the size of a typical LED and the preferable size of through holes 11a, 12a (diameter of 1 mm or more), the number of holes 11a, 12a arranged for one light source 4 is preferably about 3 to 4.

[0048] 14, the diffuser plate 10 does not necessarily have to be provided. However, since light from one light source 4 is emitted from multiple through-holes 11a and 12a, it is preferable that color unevenness and brightness unevenness within the area illuminated by one light source 4 be small, and therefore it is preferable to provide the diffuser plate 10.

[0049] (Variation 3) Furthermore, for example, the aerial display device 1 may use micro LEDs as the light sources 4. By using micro LEDs, the size of the through holes formed in the retroreflective sheet and the retardation film becomes smaller, but the relative relationship between the tilt direction and offset direction of the eye point and the relative relationship between the arrangement direction of the LED chips and the extension direction of the through holes remain the same as in the above-described embodiment.

[0050] Fig. 15 is a diagram showing an example of the configuration of an aerial display device 1 according to Modification 3. The front view of Fig. 15 corresponds to a view of the retardation film 7 seen from the emission surface side of the aerial display device 1, and the cross-sectional view corresponds to the XX cross-sectional view in the front view. Note that the configuration of the aerial display device 1 according to Modification 3 is basically the same as that shown in Figs. 1 and 2 except for the content explained in Fig. 15, and therefore the explanation will be omitted as appropriate.

[0051] As shown in FIG. 15, the aerial display device 1 of the third modification includes a light source 13, a retroreflective sheet 14, and a retardation film 15 instead of the light source 4, the retroreflective sheet 6, and the retardation film 7.

[0052] The light source 13 is a tandem LED in which three LED chips 13a, 13b, and 13c are stacked in the thickness direction (Z-axis direction). The three LED chips 13a, 13b, and 13c have different wavelengths and correspond to red (R), blue (B), and green (G) LED chips, respectively. The length of the light source 4 in the Y-axis direction is 0.21 mm.

[0053] The retroreflective sheet 14 is basically the same as the retroreflective sheet 6, except that it has through-holes 14a that are smaller than the through-holes 6a. The retardation film 15 is basically the same as the retardation film 7, except that it has through-holes 15a that are smaller than the through-holes 7a.

[0054] Each of the through holes 14a, 15a has a shape extending in substantially the same direction as the arrangement direction of the three LED chips 13a, 13b, and 13c. For example, each of the through holes 14a, 15a has an elliptical shape with a length in the Y-axis direction of 1.5 mm and a length in the X-axis direction of 1.4 mm in a front view (XY plane). This allows light from each of the three LED chips 13a, 13b, and 13c arranged in one direction to be emitted from the through holes 14a, 15a with minimal leakage, thereby improving brightness. Note that the shape of each of the through holes 14a, 15a is not limited to an ellipse, and may be a rectangle or a polygon.

[0055] Here, the center position P6 of each light source 13 is offset in approximately the same direction as the inclination of the eye point with respect to the normal direction of the retroreflective sheeting 14. In the example of FIG. 15, the eye point is set in a direction inclined 25 degrees in the negative Y-axis direction from the normal direction of the retroreflective sheeting 14. In this case, the center position P6 of each light source 13 is offset, for example, by 0.6 mm in the negative Y-axis direction from the center position P7 of each through-hole 14a corresponding to each light source 13. This can reduce color separation and improve appearance.

[0056] The three LED chips 13a, 13b, and 13c provided in the micro LED are positioned at the same position in the Y-axis direction, which makes the structure less susceptible to color separation compared to a structure in which the three LED chips 4a, 4b, and 4c are aligned in the Y-axis direction. However, by offsetting the light source 13 according to the tilt direction of the eyepoint, it is expected that brightness will be improved.

[0057] (Determining the offset amount) Next, a method for determining (calculating) the offset amount of the light source 4 will be described. For example, the offset amount is determined based on the width of the field of view, the size of the light source 4, the size of the through-holes 6a and 7a, and the distance between the light source 4 and the retroreflective sheet 6.

[0058] Fig. 16 is a diagram for explaining a method for determining the offset amount. In the example of Fig. 16, a case will be explained in which the field of view range is set to a range of 0 to 35 degrees in the negative Y-axis direction from the normal direction to the display surface.

[0059] 16, first, the upper ends p1 of the through holes 6a and 7a are set so as not to overlap the upper LED chip 4a so that the light from the three LED chips 4a, 4b, and 4c can reach the light source 4a even in the front direction. At this point, the position of the light source 4, i.e., the center position P1 of the light source 4, has already been determined.

[0060] Next, the lower ends p2 of the through holes 6a and 7a are determined so that the light from the lower LED chip 4c (arrow in FIG. 16) is included in the field of view. Here, if the size of the light source 4 (the distance from the upper LED chip 4a to the lower LED chip 4c) and the distance H between the upper end of the light source 4 and the incident surface of the retroreflective sheet 6 change, the angle of the light (arrow in FIG. 16) changes. In other words, the size of the light source 4 and the distance H are factors in determining the lower ends p2 of the through holes 6a and 7a.

[0061] Once the lower ends p2 of the through holes 6a, 7a are determined, the lengths (L) of the through holes 6a, 7a in the Y-axis direction are determined. Since the center position P2 is located midway between the determined upper and lower ends p1 and p2, the offset amount from the center position P1 is determined.

[0062] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present invention.

[0063] As described above, the aerial display device according to the embodiment includes a substrate on which a plurality of light sources are two-dimensionally arranged, and a retroreflective sheet disposed on the light-emitting side of the plurality of light sources and having a plurality of through-holes corresponding to the plurality of light sources, the center positions of the plurality of light sources being offset from the through-holes corresponding to the plurality of light sources depending on the viewpoint position. This allows the aerial display device 1 to improve the appearance of the aerial image.

[0064] The center positions of the light sources are offset in approximately the same direction as the inclination of the viewpoint relative to the normal direction of the retroreflective sheeting, thereby improving the brightness of the aerial display device 1 by reducing color separation and improving the appearance of the aerial image.

[0065] Furthermore, the central position of each of the plurality of light sources is offset from the central position of one of the through holes corresponding to each of the plurality of light sources, thereby reducing color separation and improving brightness of the aerial image, thereby improving the appearance of the aerial image.

[0066] Furthermore, the central position of each of the plurality of light sources is offset from the central positions of a predetermined number of through holes corresponding to each of the plurality of light sources, thereby enabling the aerial display device 1 to reduce loss of the aerial image when viewed from the front and improve the appearance of the aerial image.

[0067] Each of the plurality of light sources includes a plurality of LED (Light Emitting Diode) chips with different wavelengths, and each of the plurality of through holes has a shape extending in approximately the same direction as the arrangement direction of the plurality of LED chips included in each light source. This allows the aerial display device 1 to improve brightness by reducing color separation and improve the appearance of the aerial image.

[0068] The aerial display device 1 further includes a diffusion plate disposed between the substrate and the retroreflective sheet, thereby reducing color separation in the aerial display device 1.

[0069] Each of the multiple light sources is a micro LED, in which multiple LED chips with different wavelengths are stacked in the emission direction. This allows the aerial display device 1 to produce a high-definition aerial image while improving the appearance of the aerial image.

[0070] The amount of offset is determined based on the width of the field of view, the size of the light source, the size of the through-hole, and the distance between the light source and the retroreflective sheet, allowing the aerial display device 1 to appropriately determine the amount of offset.

[0071] The aerial display device 1 further includes a first polarized reflective sheet disposed between the substrate and the retroreflective sheet, a retardation film disposed on the exit side of the retroreflective sheet and having through-holes at the same positions as the through-holes of the retroreflective sheet, and a second polarized reflective sheet disposed on the exit side of the retardation film, thereby improving the brightness of the aerial display device 1.

[0072] Furthermore, the present invention is not limited to the above-described embodiments. Configurations in which the above-described components are appropriately combined are also included in the present invention. Furthermore, further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspects of the present invention are not limited to the above-described embodiments, and various modifications are possible. [Explanation of symbols]

[0073] 1 aerial display device, 2 frame, 3 substrate, 4, 13 light source, 5 polarized reflective sheet, 6, 11, 14 retroreflective sheet, 7, 12, 15 phase difference film, 8 polarized reflective sheet, 9 top cover, 10 diffusion sheet

Claims

1. a substrate on which a plurality of light sources are two-dimensionally arranged; a retroreflective sheet disposed on the exit side of the plurality of light sources and having a plurality of through holes corresponding to the plurality of light sources; Equipped with a center position of each of the plurality of light sources is offset with respect to the through hole corresponding to each of the plurality of light sources according to a viewpoint position; Aerial display device.

2. The central positions of the plurality of light sources are offset in substantially the same direction as the direction in which the viewpoint position is inclined with respect to the normal direction of the retroreflective sheet. The aerial display device according to claim 1 .

3. a central position of each of the plurality of light sources is offset from a central position of one through hole corresponding to each of the plurality of light sources; The aerial display device according to claim 1 .

4. a central position of each of the plurality of light sources is offset from a central position of a predetermined number of through holes corresponding to each of the plurality of light sources; The aerial display device according to claim 1 .

5. each of the plurality of light sources includes a plurality of LED (Light Emitting Diode) chips having different wavelengths; Each of the plurality of through holes has a shape extending in substantially the same direction as the arrangement direction of the plurality of LED chips included in each light source. The aerial display device according to claim 1 .

6. Further, a diffusion plate is disposed between the substrate and the retroreflective sheet. The aerial display device according to claim 1 .

7. Each of the plurality of light sources is a micro LED in which a plurality of LED chips having different wavelengths are stacked in the emission direction. The aerial display device according to claim 1 .

8. The amount of the offset is determined based on the width of the field of view, the size of the light source, the size of the through-hole, and the distance between the light source and the retroreflective sheet. The aerial display device according to claim 1 .

9. a first polarized reflective sheet disposed between the substrate and the retroreflective sheet; a retardation film disposed on the exit side of the retroreflective sheet and having through holes at the same positions as the through holes of the retroreflective sheet; a second polarizing reflective sheet disposed on the exit side of the retardation film; Further comprising: The aerial display device according to claim 1 .

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