Image display device

Abstract

This image display device according to one embodiment is equipped with an image-forming element and a light source. The image-forming element includes: a base material having a first surface; and a reflector array provided on the base material. The reflector array includes a plurality of reflector rows having a plurality of two-surface orthogonal reflectors provided along a first direction. The plurality of two-surface orthogonal reflectors each include: a first reflective surface to reflect light from the first surface side; and a second reflective surface which is orthogonal to the first reflective surface and reflects reflected light from the first reflective surface to the first surface side. With the base material serving as a reference, the tilt of the two-surface orthogonal reflectors is set such that an image is formed on the first surface side.

Description

【Technical Field】 【0001】 Embodiments of the present invention relate to an image display device. 【Background Art】 【0002】 A reflective imaging optical element that displays a real image of an observed object in the air and an image display device applying the same have been proposed (see, for example, Patent Document 1). 【0003】 Such an image display device can display an image when needed by a user and make the image non-displayed in other cases. Moreover, since the image is displayed in the air, there is no need for a device for the display portion, and there are advantages such as being able to more effectively utilize a limited space such as inside an automobile. 【0004】 In addition, by applying a technology capable of displaying an image in the air, a non-contact operation panel considering infectious diseases can be realized, and thus it is expected that the application fields will expand not only to use inside an automobile but also to other fields. 【0005】 As such a reflective imaging optical element, those using a two-sided orthogonal reflector and those using an optical element having a retroreflective function called a corner cube reflector have been put into practical use (see, for example, Patent Document 2, etc.). Problem points have been pointed out according to their respective operating principles. For example, in an image display device using an imaging element using a two-sided orthogonal reflector, it is considered difficult to avoid a virtual image being displayed at an unintended location by a user. 【0006】 In an image display device using a corner cube reflector, by using an optical element, the formation position of an image can be set relatively freely. On the other hand, the configuration of the optical element for that purpose becomes complicated. 【0007】 Therefore, an image display device that can display an image in the air with a simple structure is desired. 【Prior Art Documents】 [Patent Documents] 【0008】 [Patent Document 1] Japanese Patent Publication No. 2015-146009 [Patent Document 2] International Publication No. 2016-199902 [Overview of the Initiative] [Problems that the invention aims to solve] 【0009】 One embodiment of the present invention provides an image display device that can display images in the air with a simple structure. [Means for solving the problem] 【0010】 An image display device according to one embodiment of the present invention comprises an imaging element and a light source for irradiating the imaging element with light. The imaging element includes a substrate having a first surface and a second surface located opposite the first surface, and a reflector array provided on the substrate. The reflector array includes a plurality of reflector rows, each including a plurality of two-plane orthogonal reflectors provided along a first direction. Each of the plurality of two-plane orthogonal reflectors includes a first reflective surface provided to reflect light from the side of the first surface, and a second reflective surface provided perpendicular to the first reflective surface and provided to reflect reflected light from the first reflective surface back to the side of the first surface. In each of the plurality of reflector rows, the angle between the line where the first reflective surface and the second reflective surface intersect and a virtual plane including the first direction and the second direction intersecting the first direction is set to a value greater than 0° and less than 90°. The angle between the first reflective surface and the virtual plane is set to a value greater than 45° and less than 90°. The plurality of reflector rows include a first reflector row in which the angle between the straight line and the virtual plane is set to the smallest value. Of the plurality of reflector rows, the angle between the straight line and the virtual plane of the remaining reflector rows is set to a value that increases as it moves away from the first reflector row in the second direction. The light source is provided on the first surface side. Each of the plurality of two-plane orthogonal reflectors is provided so that a portion of the light emitted from the light source that is reflected once by the first reflecting surface travels toward the second reflecting surface. [Effects of the Invention] 【0011】 According to one embodiment of the present invention, an image display device capable of displaying images in mid-air with a simple structure is realized. [Brief explanation of the drawing] 【0012】 [Figure 1] This is a schematic plan view illustrating an imaging element according to the first embodiment. [Figure 2] This is a schematic perspective view illustrating a part of the imaging element of the first embodiment. [Figure 3A] It is a schematic enlarged view of part III of FIG. 1. [Figure 3B] It is a schematic enlarged view of another example of part III of FIG. 1. [Figure 3C] It is a schematic enlarged view of another example of part III of FIG. 1. [Figure 4A] It is a schematic plan view illustrating a part of the pixel element of the first embodiment. [Figure 4B] It is an example of a schematic cross-sectional view taken along line IVB-IVB’ of FIG. 4A. [Figure 4C] It is a schematic perspective view for explaining the operation of the pixel element of the first embodiment. [Figure 4D] It is a schematic perspective view for explaining the operation of the pixel element of the first embodiment. [Figure 5] It is a schematic side view illustrating the pixel element of the first embodiment. [Figure 6] It is a schematic side view illustrating the pixel element of the first embodiment. [Figure 7] It is a schematic side view illustrating the pixel element according to the first modification of the first embodiment. [Figure 8A] It is a schematic side view illustrating the pixel element according to the second modification of the first embodiment. [Figure 8B] It is a schematic side view illustrating the pixel element according to the second modification of the first embodiment. [Figure 9A] It is a schematic side view illustrating the pixel element according to the third modification of the first embodiment. [Figure 9B] It is a schematic side view illustrating the pixel element according to the third modification of the first embodiment. [Figure 10A] It is a schematic plan view illustrating a part of the pixel element according to the fourth modification of the first embodiment. [Figure 10B] It is a schematic plan view illustrating a part of the pixel element according to the fourth modification of the first embodiment. [Figure 10C] It is a schematic side view illustrating a part of the pixel element according to the fourth modification of the first embodiment. [Figure 11] This is a schematic enlarged plan view illustrating a part of the imaging element according to a fifth modification of the first embodiment. [Figure 12A] This is a schematic plan view illustrating the operation of the imaging element in the comparative example. [Figure 12B] This is an example of a schematic plan view illustrating the operation of the imaging element in the first embodiment. [Figure 13] This is a schematic side view illustrating an imaging element of another comparative example, in order to explain the operation of the imaging element of this embodiment. [Figure 14] This is an example of a schematic side view illustrating the operation of the imaging element in this embodiment. [Figure 15] This is an example of a schematic side view illustrating the operation of the imaging element in the first embodiment. [Figure 16] This is an example of a schematic side view illustrating the operation of the imaging element in the first embodiment. [Figure 17] This is an example of a schematic side view illustrating the operation of the imaging element in the first embodiment. [Figure 18] This is a schematic diagram illustrating a calculation example related to the imaging element of the first embodiment. [Figure 19] This is a schematic diagram illustrating a calculation example related to the imaging element of the first embodiment. [Figure 20A] This is a schematic diagram illustrating a calculation example related to the imaging element of the first embodiment. [Figure 20B] This is a schematic diagram illustrating a calculation example related to the imaging element of the first embodiment. [Figure 21A] This is a schematic diagram illustrating a calculation example related to the imaging element of the first embodiment. [Figure 21B] This is a schematic diagram illustrating a calculation example related to the imaging element of the first embodiment. [Figure 21C] This is a schematic diagram illustrating a calculation example related to the imaging element of the first embodiment. [Figure 22] This is a schematic side view illustrating an image display device according to the second embodiment. [Figure 23]This is a schematic plan view illustrating a part of an image display device according to a modified example of the second embodiment. [Figure 24A] This is a schematic plan view illustrating the operation of the image display device according to the second embodiment. [Figure 24B] This is a schematic side view illustrating the operation of the image display device according to the second embodiment. [Figure 25] This is a schematic side view illustrating an image display device according to the third embodiment. [Figure 26] This is a schematic side view illustrating an image display device according to the fourth embodiment. [Modes for carrying out the invention] 【0013】 Embodiments of the present invention will be described below with reference to the drawings. Please note that the drawings are schematic or conceptual, and the relationships between the thickness and width of each part, as well as the ratios of the sizes of the parts, are not necessarily identical to those of reality. Furthermore, even when representing the same part, the dimensions and ratios may differ between drawings. In this specification and in each figure, elements similar to those described above in previously mentioned figures are denoted by the same reference numerals, and detailed explanations are omitted as appropriate. 【0014】 (First embodiment) Figure 1 is a schematic plan view illustrating an imaging element according to this embodiment. As shown in Figure 1, the imaging element 10 according to this embodiment comprises a substrate 12 and a reflector array 20. The substrate 12 has a first surface 11a, and the reflector array 20 is provided on the first surface 11a. In this example, the reflector array 20 is provided within a reflector forming region 14 of the first surface 11a. The reflector array 20 includes a plurality of reflector rows 22. 【0015】 First, let's describe the composition of the base material 12. Figure 2 is a schematic perspective view illustrating a part of the imaging element of this embodiment. As shown in Figure 2, the substrate 12 has a first surface 11a and a second surface 11b. The second surface 11b is located on the opposite side of the first surface 11a. 【0016】 In this specification, the configuration of imaging elements and image display devices may be described using a right-handed three-dimensional coordinate system of XYZ. The XY plane is defined as a plane parallel to the virtual plane P0. The first plane 11a is located on the positive Z-axis side than the second plane 11b. The first plane 11a includes a portion of a circular arc that is convex towards the negative Z-axis side in a YZ plane view. In the specific example described below, the virtual plane P0 is a virtual plane parallel to the tangent plane that touches the point on the most negative Z-axis side of this circular arc. 【0017】 The first surface 11a is a curved surface, and the reflector array 20 is mounted on this curved surface. The virtual plane P0 serves as the reference plane when setting the inclination of the reflector row 22 in the Y-axis direction. In other words, the reflector row 22 is mounted on the first surface 11a at an angle set with respect to the virtual plane P0. 【0018】 The base material 12 is made of a light-transmitting material, for example, a transparent resin. 【0019】 In the imaging element 10 of this embodiment, when the light source is placed on the first surface 11a side with respect to the substrate 12, an image is formed on the first surface 11a side where the light source is placed, rather than on the second surface 11b side. The position where the image is formed can be a position sufficiently far from the position where the light source is provided, and can be a position different from the position where the light source is provided. 【0020】 Returning to Figure 1, we continue the explanation. The reflector rows 22 are arranged along the X-axis. Multiple reflector rows 22 are arranged along the Y-axis so as to be approximately parallel to each other. Multiple reflector rows 22 are arranged at approximately equal intervals, with a gap 23 in the Y-axis direction between adjacent reflector rows 22. The length of the gap 23 in the Y-axis direction of the reflector rows 22 can be any length, for example, it can be approximately the length of the Y-axis direction of the reflector row 22. Light rays that are not reflected by the reflector rows 22 or reflected light that is reflected only once by the reflector rows 22 are incident on the region forming the gap 23 of the reflector rows 22 when the light source is placed on the first surface 11a side. Since these light rays do not contribute to imaging, if this gap 23 is made wider, the proportion of light rays incident on the imaging element 10 that contribute to imaging will decrease. For this reason, the length of the gap 23 in the Y-axis direction is set to an appropriate length depending on the dimensions of the two-plane orthogonal reflector and the efficiency of the reflective surface, which will be described later in relation to Figure 3A. Each of the reflector rows 22 contains numerous two-plane orthogonal reflectors connected in the X-axis direction, and is therefore shown as a filled-in area in Figure 1 to avoid complexity. 【0021】 Figure 3A is a schematic enlarged view of part III of Figure 1. As shown in Figure 3A, the reflector row 22 includes a plurality of two-plane orthogonal reflectors 30. The plurality of two-plane orthogonal reflectors 30 are connected to each other and arranged in a continuous manner along the X-axis. The two-plane orthogonal reflectors 30 include a first reflective surface 31 and a second reflective surface 32. The two-plane orthogonal reflectors 30 are mounted on a base 36 formed on the first surface 11a shown in Figure 1. The first reflective surface 31 and the second reflective surface 32 are approximately square in front view and are connected approximately orthogonally along one side of the square. 【0022】 Hereinafter, in the two-plane orthogonal reflector 30, the connection line between the first reflective surface 31 and the second reflective surface 32 will be referred to as the valley-side connection line 33. The edge of the first reflective surface 31 on the opposite side of the valley-side connection line 33, and the edge of the second reflective surface 32 on the opposite side of the valley-side connection line 33 will be referred to as the mountain-side connection line 34. 【0023】 The first reflective surface 31 of a two-plane orthogonal reflector 30 is connected by a mountain-side connecting line 34 to the second reflective surface 32 of an adjacent two-plane orthogonal reflector 30 on the negative side of the X-axis. The second reflective surface 32 of a two-plane orthogonal reflector 30 is connected by a mountain-side connecting line 34 to the first reflective surface 31 of the other two-plane orthogonal reflector 30 adjacent on the positive side of the X-axis. In this way, multiple two-plane orthogonal reflectors 30 are interconnected and continuously arranged along the X-axis direction. 【0024】 In the imaging element 10 of this embodiment, the dimensions of the first reflective surface 31 and the second reflective surface 32 can be, for example, several micrometers to several hundred micrometers. For example, the number of integrated two-plane orthogonal reflectors 30 is set according to the size and resolution of the aerial image to be displayed. For example, several tens to several thousand two-plane orthogonal reflectors 30 are integrated in one imaging element 10. For example, 1000 two-plane orthogonal reflectors, each having a 100 micrometer square reflective surface, can be arranged over a distance of about 14 cm in the Y-axis direction. 【0025】 The reflector row 22 of the imaging element 10 is arranged so that the X-axis positions of the valley-side connecting line 33 and the mountain-side connecting line 34 are the same, as shown in the enlarged view in Figure 3A. However, the X-axis positions of the valley-side connecting line 33 and the mountain-side connecting line 34 may be shifted for each reflector row 22. 【0026】 Figure 3B is a schematic enlarged view of another example from Part III of Figure 1. As shown in Figure 3B, the positions of the valley-side connecting line 33 and the mountain-side connecting line 34 in the X-axis direction are shifted for each adjacent reflector row 22. The amount of shift for each reflector row 22 may be any value or a constant value. 【0027】 In the example shown in Figure 3B, the amount of X-axis displacement of the valley-side connecting line 33 and the mountain-side connecting line 34 is constant for each reflector row 22. In this example, the X-axis position of the valley-side connecting line 33 of a two-plane orthogonal reflector 30 in one reflector row 22 coincides with the X-axis position of the mountain-side connecting line 34 of a two-plane orthogonal reflector 30 in the reflector row 22 adjacent to that reflector row 22. The X-axis position of the mountain-side connecting line 34 of a two-plane orthogonal reflector 30 in one reflector row 22 coincides with the X-axis position of the valley-side connecting line 33 of a two-plane orthogonal reflector 30 in the reflector row 22 adjacent to that reflector row 22. In other words, if we define one period as the distance between the valley-side connecting lines 33 or the mountain-side connecting lines 34 of two adjacent orthogonal reflectors 30, then the orthogonal reflectors 30 in adjacent reflector rows 22 are arranged with a phase shift of 1 / 2 period each. 【0028】 In this example, the spacing 23 shown in Figure 3A is not provided. The spacing 23 is zero. In this case, the base 36 may function as a spacing. As will be described later in the operation of the imaging element 10, there are cases where the light rays incident on the two-plane orthogonal reflector 30 do not undergo a second reflection, and the light reflected once needs to pass through the spacing 23 of the adjacent reflector row 22 to the second plane side. For this reason, in the example shown in Figure 3B, the base 36 is formed to either transmit or absorb light. 【0029】 Figure 3C is a schematic enlarged view of another example from Part III of Figure 1. As shown in Figure 3C, between the rows of reflectors 22 aligned in the Y-axis direction, a base portion 36 inclined with respect to the XY plane may be provided, rather than being limited to the flat, strip-shaped spacing 23 shown in Figure 3A. As mentioned above, the phase of the valley-side connecting line 33 and mountain-side connecting line 34 between adjacent rows of reflectors 22 may be arbitrary. 【0030】 When the imaging elements shown in Figures 3B and 3C are used in the image display devices 1000, 1100, and 1200, which will be described later in relation to Figures 22 to 26, as described above, by giving the base portion 36 light transmittance or light absorption, it becomes difficult to observe a virtual image on the first surface side. 【0031】 Figure 4A is a schematic plan view illustrating a part of the imaging element of this embodiment. Figure 4B is an example of a schematic cross-sectional view taken along the line IVB-IVB' in Figure 4A. Figures 4A and 4B show the configuration of the two-plane orthogonal reflector 30. As shown in Figures 4A and 4B, the two-plane orthogonal reflector 30 includes a first reflective surface 31 and a second reflective surface 32, which are provided on a base 36. The base 36 is provided such that the first reflective surface 31 and the second reflective surface 32 are at a desired angle with respect to the tangent plane P of the first surface 11a. The base 36 is a translucent member molded in a V shape, and is made of, for example, transparent resin and molded integrally with the substrate 12. The first reflective surface 31 and the second reflective surface 32 are formed by forming a thin film of a light-reflective metal material or the like on the V-shaped portion of the substrate 12. The present invention is not limited to this example, but the first reflective surface 31, the second reflective surface 32, the base 36, and the substrate 12 may each or part of them be formed separately and assembled together to form the imaging element 10. Furthermore, if the surface of the transparent resin is, for example, mirror-finished and the surface reflectivity of the transparent resin is sufficiently high, the first reflective surface 31 and the second reflective surface 32 can be left as the surface of the transparent resin. The base 36, which was described in relation to the spacing 23 and Figure 3B, is preferably made to have light transmittance or light absorption properties in order to prevent virtual image observation, etc. 【0032】 The first reflective surface 31 and the second reflective surface 32 are connected by a valley-side connecting line 33 so as to be approximately perpendicular. On the first reflective surface 31, there is a mountain-side connecting line 34 on the opposite side of the valley-side connecting line 33, and on the second reflective surface 32, there is a mountain-side connecting line 34 on the opposite side of the valley-side connecting line 33. 【0033】 The ends of the valley-side connecting line 33 are called vertices 33a and 33b. The position of vertex 33a is on the positive Z-axis side than the position of vertex 33b. In other words, vertex 33a is located further from the base material 12 than vertex 33b. The ends of the mountain-side connecting line 34 are called vertices 34a and 34b. The position of vertex 34a is on the positive Z-axis side than the position of vertex 34b. In other words, vertex 34a is located further from the base material 12 than vertex 34b. Therefore, vertex 34a is the position furthest from the base material 12, and vertex 33b is located closest to the base material 12. 【0034】 Figure 4B shows the relationship between the two-plane orthogonal reflector 30, the first surface 11a, and the tangent plane P. The two-plane orthogonal reflector 30 is tangent to the first surface 11a at the lower vertex 33b of the valley-side connecting line 33. The tangent plane P is a plane tangent to the first surface 11a at the position of vertex 33b and is parallel to the virtual plane P0. The two-plane orthogonal reflector 30 is provided on the first surface 11a such that the valley-side connecting line 33 makes an angle θ with the tangent plane P. 【0035】 Figure 4C is a schematic perspective view illustrating the operation of the imaging element in this embodiment. As shown in Figure 4C, when a light ray LL is incident on the first reflecting surface 31, the light ray LL is reflected by the first reflecting surface 31. The light LR1 reflected once by the first reflecting surface 31 is reflected again by the second reflecting surface 32. The light LR2 reflected twice by the second reflecting surface 32 is emitted on the same side as the light source of the incident light. In this way, the two-plane orthogonal reflector 30 emits the incident light from the first surface 11a side toward a position on the first surface 11a side that is different from the position of the light source. In this manner, the two-plane orthogonal reflector 30 reflects the light twice by its two reflecting surfaces and reflects the light LR2 twice toward the side from which the incident light ray LL has traveled. 【0036】 Figure 4D is a schematic perspective view illustrating the operation of the imaging element in this embodiment. The reflection operation of the two-plane orthogonal reflector 30 is reversible. When a light ray incident on the two-plane orthogonal reflector 30 is incident from the opposite direction along the twice-reflected light LR2 in Figure 4C, it is reflected in the opposite direction along the incident light ray LL. Specifically, as shown in Figure 4D, the light ray LL incident on the two-plane orthogonal reflector 30 is reflected by the second reflective surface 32 and incident on the first reflective surface 31 as once-reflected light LR1. The once-reflected light LR1 is reflected by the first reflective surface 31 and emitted as twice-reflected light LR2. 【0037】 As shown in Figures 3 and 4A, the two-plane orthogonal reflector 30 is symmetrical with respect to the valley-side connecting line 33, and the angle of the first reflecting surface 31 with respect to the tangent plane P is approximately equal to the angle of the second reflecting surface 32 with respect to the tangent plane P. Therefore, the two-plane orthogonal reflector 30 operates similarly and emits reflected light whether the light ray first incident on the first reflecting surface 31 or first incident on the second reflecting surface 32. For example, in Figure 4C, the light ray LL is assumed to first incident on the first reflecting surface 31 and be reflected, but as shown in Figure 4D, even if the light ray first incident on the second reflecting surface 32 and is reflected, the operation of the two-plane orthogonal reflector 30 can be explained in the same way as above. Also, in Figure 4D, the light ray LL may first incident on the first reflecting surface 31, and the light reflected once by the first reflecting surface 31 may be reflected by the second reflecting surface 32 and emitted as second reflected light. In the following, when describing the operation of the imaging element, unless otherwise specified, the first case will be described when reflection occurs at the first reflective surface 31. 【0038】 Figure 5 is a schematic side view illustrating the imaging element of this embodiment. In Figure 5, the reflector array 20 is shown by the envelope connecting the vertices 33a of the two-plane orthogonal reflector 30 shown in Figures 4A and 4B. Hereafter, in side views, unless it is necessary to show and explain the configuration of the two-plane orthogonal reflector 30, the reflector array 20 will be represented by the envelope of the vertices 33a of the two-plane orthogonal reflector 30 as a dashed line, as shown in Figure 5. 【0039】 As shown in Figure 5, in the imaging element 10 of this embodiment, the first surface 11a is a curved surface, so the reflector array 20 is provided in a curved shape. The first surface 11a includes a part of an arc that is convex to the negative direction of the Z axis in a YZ plane view, and the reflector array 20 is also provided in this arc shape, and the envelope of the vertices is also an arc. The radius of the arc is set based on the distance between the imaging element 10 and the light source provided on the first surface 11a side of the imaging element 10. For example, the radius of the arc of the reflector array 20 is set to about twice the distance between the imaging element 10 and the light source. 【0040】 As explained in relation to Figures 4C and 4D, the imaging element 10 is reversible with respect to the direction of incidence and reflection of light rays. When the direction of incidence and reflection is reversed in the imaging element 10, the radius of the arc is set based on the distance between the imaging element 10 and the image formed on the first surface 11a side. Similarly, the radius of the arc of the reflector array 20 is set to approximately twice the distance between the imaging element 10 and the image. 【0041】 In this embodiment, among the tangent planes that contact the first surface 11a, the tangent plane that contacts the lowest position on the negative side in the Z-axis direction is a virtual plane P0 parallel to the XY plane. 【0042】 Figure 6 is a schematic side view illustrating the imaging element of this embodiment. Figure 6 shows one of the two-plane orthogonal reflectors that make up the reflector row 22 shown in Figures 1 and 3. As explained in relation to Figures 1 and 3, each of the multiple reflector rows 22 is provided along the X-axis direction and arranged at approximately equal intervals in the Y-axis direction. The angles of the multiple two-plane orthogonal reflectors that make up one reflector row 22 with respect to the virtual plane P0 are assumed to be approximately the same. Therefore, the angle of a two-plane orthogonal reflector 30 with respect to the virtual plane P0 represents the angle of the reflector row 22 to which the two-plane orthogonal reflector 30 belongs with respect to the virtual plane P0. In Figure 6, five of the numerous two-plane orthogonal reflectors arranged in the Y-axis direction are schematically shown in an enlarged view, specifically two-plane orthogonal reflectors 30-1 to 30-5. Although the symbols are changed to distinguish their positions along the Y-axis, the configuration of two-plane orthogonal reflectors 30-1 to 30-5 is the same as that of two-plane orthogonal reflector 30 described in relation to Figures 4A and 4B. The notation for the base portion 36 shown in Figure 4B has been omitted from the illustration to avoid complexity. 【0043】 As shown in Figure 6, the two-plane orthogonal reflectors 30-1 to 30-5 have different angles Θ1 to Θ5 with respect to the virtual plane P0, depending on the position of the first surface 11a on the Y axis. The angles Θ1 to Θ5 of the two-plane orthogonal reflectors 30-1 to 30-5 are represented by the angles of the valley-side connecting lines (straight lines) 33-1 to 33-5 with respect to the virtual plane P0. 【0044】 In this example, the two-plane orthogonal reflectors 30-1 to 30-5 are arranged in this order in the positive direction of the Y-axis. The angles Θ1 to Θ5 of the two-plane orthogonal reflectors 30-1 to 30-5 are set to increasing values ​​in this order, i.e., Θ1 < Θ2 < Θ3 < Θ4 < Θ5. 【0045】 More generally, the angles Θ1 to Θ5 of the two-plane orthogonal reflectors 30-1 to 30-5 are defined as follows: relative to the reflector row (first reflector row) 22 of the two-plane orthogonal reflector set to the smallest angle, the angles increase as the angle moves away in one direction along the Y-axis. Conversely, the angles Θ1 to Θ5 are defined as the angle moves away in other directions along the Y-axis from the reference reflector row 22. In the example in Figure 6, relative to the position of the two-plane orthogonal reflector 30-1 set to the smallest angle, the angles are Θ1 < Θ2 < Θ3 < Θ4 < Θ5 in the positive direction along the Y-axis. 【0046】 The angles Θ1 to Θ5 of the two orthogonal reflectors can be set to 0° < Θ1 to Θ5 < 90°. The angle between the first reflective surface 31 and the virtual plane P0 is determined in conjunction with the angles Θ1 to Θ5, but can be set to 45° < (angle between the first reflective surface 31 and the virtual plane P0) < 90°. The angle between the second reflective surface 32 and the virtual plane P0 is equal to the angle between the first reflective surface 31 and the virtual plane P0. Therefore, 45° < (angle between the second reflective surface 32 and the virtual plane P0) < 90°. 【0047】 The inclination of each of the two-plane orthogonal reflectors 30-1 to 30-5 is also determined by the angle with respect to the tangent planes P1 to P5 on the first surface 11a where the two-plane orthogonal reflectors 30-1 to 30-5 are arranged. The angle of the two-plane orthogonal reflectors 30-1 to 30-5 with respect to the tangent planes P1 to P5 is a constant angle θ, regardless of the position of the two-plane orthogonal reflectors 30-1 to 30-5 on the Y-axis. For example, the angle θ is based on the angle that each reflective surface of the corner cube reflector makes with the horizontal plane, and is set to approximately 30°, or more specifically, 35.3°. 【0048】 In the imaging element 10 of this embodiment, the angles Θ1 to Θ5 of the two orthogonal reflectors 30-1 to 30-5 are appropriately set so that, with respect to the substrate 12, the light rays incident from the light source provided on the first surface 11a side are imaged on the first surface 11a side. The imaging position is in the air, different from the position of the light source. The angles of the two orthogonal reflectors with respect to the virtual plane P0 are determined, for example, by experimentation or simulation. 【0049】 The angle of the two-plane orthogonal reflector with respect to the virtual plane P0 only needs to be set to increase or decrease depending on the position on the Y-axis, so the first plane 11a does not have to be part of a circular arc. For example, the first plane 11a may be part of an elliptical arc, or part of a polygon corresponding to the number of rows of reflector. Also, since the angle of the two-plane orthogonal reflector only needs to be set according to the position of the two-plane orthogonal reflector on the Y-axis, the reference may not be the virtual plane P0, but another plane that makes an arbitrary angle with respect to the virtual plane P0. 【0050】 (First variation) Figure 7 is a schematic side view illustrating an imaging element according to this modified example. In this modified example, the configuration of the base material 112 differs from that of the first embodiment described above. The configurations other than the base material 112 are the same as in the first embodiment, and the same reference numerals are used for the same components, and detailed descriptions are omitted as appropriate. As shown in Figure 7, the imaging element 110 of this modified example comprises a reflector array 20 and a substrate 112. The substrate 112 has a first surface 11a and a second surface 111b. The reflector array 20 is provided on the first surface 11a. The second surface 111b is provided on the opposite side of the first surface 11a. In this modified example, the second surface 111b has the same shape as the first surface 11a, and both the first surface 11a and the second surface 111b include a portion of a circular arc with the same radius in a YZ plan view. In this example, the shape of the second surface 111b in a YZ plan view is not limited to being the same as the shape of the first surface 11a in a YZ plan view, but may be any different shape. 【0051】 The base material 112 is formed of a light-transmitting material, similar to the first embodiment, and is formed of, for example, a transparent resin. 【0052】 The reflector array 20 only needs to have the angles of the two orthogonal reflectors with respect to the virtual plane P0 and the angles of the two orthogonal reflectors with respect to the tangent plane of the first surface 11a set in the same way as in the first embodiment. Therefore, the shape of the second surface 111b of the substrate 112 can be arbitrary. For example, by making it a shape suitable for the location where the imaging element 110 is housed, it becomes possible to reduce the storage space. 【0053】 (Second variation) Figures 8A and 8B are schematic side views illustrating the imaging element according to this modified example. In this modified example, the configuration of the base material 212 differs from that of the first embodiment and the first modified example described above. In this modified example, the location where the reflector array 20 is provided differs from that of the first embodiment and the first modified example. The other configurations are the same as in the first embodiment, and the same reference numerals are used for the same components, and detailed descriptions are omitted. 【0054】 As shown in Figure 8A, the imaging element 210 comprises a reflector array 20 and a substrate 212. The substrate 212 has a first surface 211a and a second surface 211b. The substrate 212 is made of a light-transmitting material, for example, a transparent resin. The reflector array 20 is provided on the second surface 211b. In this example, the second surface 211b is the inner surface of the substrate 212, and the reflector array 20 is provided inside the substrate 212. The reflector array 20 is provided to reflect light rays from the first surface 211a side and to image them towards the first surface 211a side. If the two reflective surfaces of the two-plane orthogonal reflector 30 are oriented toward the first surface 211a side, the outer surface of the substrate 212 may be the second surface 211b, and the reflector array 20 may be formed on the second surface 211b, outside the substrate 212. 【0055】 The second surface 211b includes a portion of a circular arc that is convex towards the negative Z-axis in a YZ-plane view. In this example, the virtual plane P0 is a virtual plane parallel to the tangent plane that touches the portion of this circular arc at the most negative Z-axis position. The second surface 211b is such a curved surface, and the reflector array 20 is mounted on this curved surface. 【0056】 In the modified example described in relation to Figure 8A, the substrate 212 has a thicker structure, with a certain distance between the first surface 211a and the second surface 211b at both ends in the Y-axis direction. Since the light rays incident on the imaging element 210 reach the reflector array 20 via the substrate 212, it is preferable to reduce the thickness of the substrate 212. 【0057】 As shown in Figure 8B, the imaging element 210a comprises a reflector array 20 and a substrate 212a. The substrate 212a has a first surface 211a and a second surface 211b, and the distance between the first surface 211a and the second surface 211b is approximately zero at both ends in the Y-axis direction. 【0058】 Thus, the shape of the substrate can be arbitrarily selected to suit the size of the imaging element, the material of the substrate, the application, etc. 【0059】 (Third variation) Figures 9A and 9B are schematic side views illustrating the imaging element according to this modified example. If the angle of the two orthogonal reflectors with respect to the virtual plane P0 can be set in the same manner as in the first embodiment described above, the reflector array 20 does not need to be formed on a curved surface, and may be provided on a single plane. In Figures 9A and 9B, the five two-plane orthogonal reflectors 30-1 to 30-5 are shown in an enlarged and schematic manner, similar to the explanation given in relation to Figure 6. The inclination of each of the five two-plane orthogonal reflectors 30-1 to 30-5, corresponding to their respective positions, is also shown. 【0060】 As shown in Figure 9A, the imaging element 310 of this modified example comprises a reflector array 20 and a substrate 312. The substrate 312 has a first surface 311a and a second surface 311b. The second surface 311b is located on the opposite side of the first surface 311a. The first surface 311a is a plane substantially parallel to the XY plane. The first surface 311a may be a virtual plane P0. The substrate 312 can be formed of a translucent material, as in the first embodiment and other modifications. 【0061】 The angles of the two-plane orthogonal reflectors 30-1 to 30-5 with respect to the virtual plane P0 are Θ1 to Θ5, respectively, and the magnitudes of Θ1 to Θ5 are Θ1 < Θ2 < Θ3 < Θ4 < Θ5. The positions of the two-plane orthogonal reflectors 30-1 to 30-5 on the Y-axis are the same as the positions of the two-plane orthogonal reflectors 30-1 to 30-5 on the Y-axis shown in Figure 6. Therefore, when the tangent planes P1 to P5 of the arc correspond to the positions on the Y-axis in the case of Figure 6, the angles between the two-plane orthogonal reflectors 30-1 to 30-5 and the tangent planes P1 to P5 are all the same value of angle θ. 【0062】 As shown in Figure 9B, the imaging element 310a of this modified example comprises a reflector array 20, a substrate 312, and further comprises a protective layer 314. The configuration of the reflector array 20 and the substrate 312 is the same as that of the imaging element 310 described in relation to Figure 9A. The protective layer 314 is provided to cover the reflector array 20 and the first surface 311a. 【0063】 The protective layer 314 is made of a highly light-transmitting material such that the amount of light transmitted is approximately constant when light rays are incident on the imaging element 310a through the protective layer 314. It is also preferable that the surface 313a of the protective layer 314 has sufficient flatness so that the refraction angle of the incident light rays is approximately constant. 【0064】 In this modified example, the base material 312 can be made flat, which reduces the thickness of the base material that would otherwise be required to make the first and second surfaces curved. This makes it possible to make the imaging elements 310 and 310a thinner. The imaging element 310 shown in Figure 9A has a reflector array 20 formed on its surface and a flat surface on the other side. Therefore, it is suitable for production using a press machine with a resin base material. Furthermore, the imaging element 310 has advantages in terms of production, such as being easy to produce using the roll-to-roll method. The roll-to-roll method is a production method in which the material of a base material wound in a roll is continuously supplied to the process for processing and treatment. The roll-to-roll method is commonly used for the production of plate-shaped and film-shaped resin molded products. 【0065】 (Fourth variation) Figures 10A to 10C are schematic plan and side views illustrating a part of the imaging element according to this modified example. Figures 10A to 10C show the configuration of the substrate of the imaging element. In the first embodiment described above and the other modifications described above, there are rays of light that do not enter either the first reflective surface 31 or the second reflective surface 32, and such rays pass through in the negative direction of the Z axis. For example, a portion of the rays emitted from the same point light source is reflected by the first reflective surface 31 and heads toward the second reflective surface 32, while another portion of the rays passes through in the negative direction of the Z axis without heading toward the second reflective surface 32. The remaining rays are not reflected by any reflective surface and continue straight ahead. The rays and reflected light that pass through to the second surface may be transmitted through the substrate or absorbed. In this modification, a component that absorbs the rays and reflected light that pass through to the second surface is added to the substrate. 【0066】 As shown in Figure 10A, the substrate 12 has a light absorber (light absorbing member) 414 formed on the first surface 11a. The light absorber 414 is provided in the region between the reflector rows 22 shown in Figure 1. The light absorber 414 is formed, for example, by applying black paint to the region between the reflector rows 22. The reflector rows 22 are formed in areas where the light absorber 414 is not applied, but the exposed portion of the base 36 shown in Figures 3, 4A, and 4B may also be coated with black paint. 【0067】 As shown in Figure 10B, the substrate 12 has a light-absorbing member 514. The light-absorbing member 514 is provided across the reflector-forming region 14 on the first surface 11a. When the pitch of the reflector rows is narrow, there is an advantage in that the formation of the light-absorbing member 514 becomes easier. The light-absorbing member 514 may also be provided across the second surface 11b. 【0068】 As explained in relation to Figures 8A and 8B, when a reflector array is provided on the second surface side, the light absorber 414 and the light absorbing member 514 may be formed on the second surface 211b of the substrate. 【0069】 When a reflector array is formed on the first surface, the entire substrate may be made of a light-absorbing material. As shown in Figure 10C, the substrate 612 is made of a light-absorbing material, for example, black resin. By making the entire substrate light-absorbing, it is possible to prevent light rays that pass through the reflector array and travel to the second surface side from being reflected by the second surface 611b and returning to the first surface 611a side. 【0070】 (Fifth variation) Figure 11 is a schematic enlarged plan view illustrating a part of the imaging element according to this modified example. Figure 11 shows an enlarged plan view of the modified example, specifically the area corresponding to part III in Figure 1. As explained in relation to Figure 3, the first reflective surface 31 and the second reflective surface 32 of the two-plane orthogonal reflector 30 are approximately square when viewed from the front, but they are not limited to this and may be rectangular. As shown in Figure 11, each of the multiple reflector rows 722 contains multiple two-plane orthogonal reflectors 730. The two-plane orthogonal reflector 730 has a first reflective surface 731 and a second reflective surface 732. Both the first reflective surface 731 and the second reflective surface 732 have a rectangular shape with the longer side in the Y-axis direction when viewed from the front. For example, the spacing between adjacent reflector rows 722 is the same as the spacing between reflector rows 22 described in relation to Figure 3. 【0071】 The first reflective surface 731 and the second reflective surface 732 are connected by a valley-side connecting line 733, and adjacent two-plane orthogonal reflectors 730 are connected to each other by a mountain-side connecting line 734. As explained in relation to Figures 3A and 3B, the phase of the arrangement of two-plane orthogonal reflectors 730 in adjacent reflector rows 722 may be arbitrary or shifted by half a period. Alternatively, the spacing between adjacent reflector rows 722 may be set to zero, and the base 36 may be used as the spacing. 【0072】 By making the sides of the first reflective surface 731 and the second reflective surface 732 along the Y-axis direction the longer sides, the area for reflecting light rays is increased. The imaging element of this modified example can achieve a higher brightness of display during imaging than that of a square reflective surface. In this modified example, the first and second reflective surfaces are rectangles with the sides along the Y-axis direction as the longer sides, but they may also be rectangles with the sides along the Y-axis direction as the shorter sides. By doing so, the length of the two-plane orthogonal reflector in the Y-axis direction can be reduced, and the imaging element can be miniaturized. When the length of the two-plane orthogonal reflector in the Y-axis direction is reduced, the area of ​​each reflective surface becomes smaller. Therefore, the number of two-plane orthogonal reflectors formed per unit area can be increased, making it possible to form a higher-resolution image. 【0073】 Each of the above-described modifications can be applied in appropriate combinations. For example, a two-sided orthogonal reflector having a rectangular first reflective surface and a second reflective surface can be applied to the substrates 212 and 212a described in relation to Figures 8A and 8B. The combination of modifications is not limited to two types, but can be three or more types. For example, a two-sided orthogonal reflector having a rectangular first reflective surface and a second reflective surface can be applied to the substrate 312 and protective layer 314 described in relation to Figures 9A and 9B, and the substrate can be formed from a light-absorbing material as described in relation to Figure 10C. 【0074】 Next, the operation of the imaging element in this embodiment and its modified examples will be described, including its operating principle. In the following, unless otherwise specified, the imaging element 10 in the first embodiment described in relation to Figures 1 to 6 will be described. The operation of the modified examples can be understood in the same way as in the first embodiment. The imaging element of this embodiment utilizes part of the operating principle of a corner cube reflector to form an image on the side of the incident light. Therefore, we will first explain the operating principle of the corner cube reflector, and then explain the operation of the imaging element of this embodiment. 【0075】 Figure 12A is a schematic plan view illustrating the operation of the imaging element of the comparative example. Figure 12A shows the configuration of the corner cube reflector and how the incident light is reflected. As shown in Figure 12A, the corner cube reflector has a first reflecting surface 31, a second reflecting surface 32, and a third reflecting surface 35. The first reflecting surface 31, the second reflecting surface 32, and the third reflecting surface 35 are connected to each other at approximately orthogonal angles. The first reflecting surface 31, the second reflecting surface 32, and the third reflecting surface 35 are positioned such that the vertex 33b to which the first reflecting surface 31, the second reflecting surface 32, and the third reflecting surface 35 are connected is at the lowest position in the Z-axis direction. 【0076】 The light ray LL incident on the first reflecting surface 31 is reflected by the first reflecting surface 31. The light LR1 reflected once by the first reflecting surface 31 is reflected by the second reflecting surface 32. The light LR2 reflected twice by the second reflecting surface 32 is reflected by the third reflecting surface 35. The light LR3 reflected three times by the third reflecting surface 35 is emitted from the corner cube reflector. Since the law of reflection holds at each reflecting surface, the light LR3 emitted from the corner cube reflector is parallel to the light ray LL incident on the corner cube reflector. In the above description, it was assumed that the light ray LL was incident on the first reflecting surface 31, but even if it were incident on the second reflecting surface 32 or the third reflecting surface, the emitted light would be parallel to the incident light. This operation is called retroreflection. 【0077】 Figure 12B is a schematic plan view illustrating the operation of the imaging element in this embodiment. As shown in Figure 12B, the first reflective surface 31 and the second reflective surface 32 are arranged almost orthogonally and connected by a valley-side connecting line 33. The vertex 33b is positioned to be the minimum value in the Z-axis direction. Comparing the corner cube reflector in Figure 12A with the two-face orthogonal reflector 30, the two-face orthogonal reflector 30 differs from the corner cube reflector in that it does not have a third reflective surface 35. 【0078】 Because the two-plane orthogonal reflector 30 does not have the third reflective surface 35 shown in Figure 12A, the twice-reflected light LR2 reflected by the second reflective surface 32 continues to travel in a straight line. Here, since the valley-side connecting line 33 is provided at a predetermined angle from the XY plane, the twice-reflected light LR2 emitted from the two-plane orthogonal reflector 30 is emitted on the same side as the incident light ray LL. 【0079】 Figure 13 is a schematic side view illustrating an imaging element of another comparative example in order to explain the operation of the imaging element of this embodiment. In Figure 13, the multiple reflector rows 22 shown in Figures 1 and 3 are arranged along the X-axis, and the multiple reflector rows 22 are arranged at regular intervals along the Y-axis. Figure 13 shows three two-plane orthogonal reflectors 30-1 to 30-3. The two-plane orthogonal reflectors 30-1 to 30-3 are shown one by one from the three reflector rows 22. The two-plane orthogonal reflectors 30-1 to 30-3 are shown slightly rotated on the XY plane to show how light rays are reflected. The signs are changed to distinguish the position on the Y-axis, but the configuration of the two-plane orthogonal reflectors 30-1 to 30-3 is the same as the two-plane orthogonal reflector 30 described in relation to Figures 4A and 4B. 【0080】 The two-plane orthogonal reflectors 30-1 to 30-3 are arranged on a virtual plane P0 and are linearly aligned along the Y-axis. The light source S is located directly above the two-plane orthogonal reflector 30. More specifically, the light source S is located above the two-plane orthogonal reflectors 30-1 to 30-3 such that a ray parallel to the Z-axis is incident on one of the two-plane orthogonal reflectors 30-1 to 30-3. The light source S has a two- or three-dimensional spread, and Figure 13 shows the case where a ray emitted from one of its points is incident on each of the two-plane orthogonal reflectors 30-1 to 30-3. The configuration of the light source S and the two-plane orthogonal reflectors 30-1 to 30-3 is the same as that of Figures 14 and 15, which will be described later. 【0081】 As shown in Figure 13, a light ray LL emitted from a light source S and incident on the first reflective surface 31 of the two-plane orthogonal reflectors 30-1 to 30-3 is reflected by the first reflective surface 31 of the two-plane orthogonal reflectors 30-1 to 30-3 to the second reflective surface 32. The three second reflective surfaces 32 each emit twice-reflected light LR2. Here, the three two-plane orthogonal reflectors 30-1 to 30-3 are arranged at the same angle θ with respect to the virtual plane P0. The angle θ is assumed to be greater than 0° and less than 90°. For example, the angle θ is assumed to be 35.3°. According to the law of reflection at each reflective surface, the twice-reflected light LR2 emitted by the two-plane orthogonal reflectors 30-1 to 30-3, which are aligned along the Y axis, spread out without forming an image. When θ is set to 0°, the image is formed on the side of the light source S (see Patent Document 1, etc.), and when θ is set to 90°, the image is formed on the opposite side of the light source S, with the image forming element as the reference, via a two-plane orthogonal reflector, resulting in the operation of a transmissive imaging element. 【0082】 The angle θ is equal to the angle of the corner cube reflector with respect to the mounting surface, as explained in relation to Figure 12A. In other words, angle θ is the angle of the retroreflective imaging element using the corner cube reflector with respect to the mounting surface. This angle is the angle of the connection line between the first reflective surface 31 and the second reflective surface 32 with respect to the mounting surface. The mounting surface of the corner cube reflector corresponds to the virtual plane P0 in Figure 13. 【0083】 In the imaging element of this embodiment, the two-plane orthogonal reflector 30 is positioned at an angle with respect to the virtual plane P0 that changes depending on its position along the Y axis, so that the reflected light, which has been reflected twice by the two-plane orthogonal reflector 30, is reflected back to the same side as the light source S to form an image. 【0084】 Figures 14 and 15 are schematic side views illustrating the operation of the imaging element in this embodiment. As shown in Figure 14, in the imaging element of this embodiment, the first surface 11a is set as part of an arc so as to be convex to the negative Z-axis side in a YZ-plane view. The two-plane orthogonal reflectors 30-1 to 30-3 are arranged on the first surface 11a. The angles Θ1 to Θ3, which represent the inclination of the two-plane orthogonal reflectors 30-1 to 30-3 with respect to the virtual plane P0, are set to increase toward the positive Y-axis in this example. By setting the angles Θ1 to Θ3 in this way, the twice-reflected light LR2, which has been reflected twice by the two-plane orthogonal reflector 30, forms an image I on the first surface 11a side where the light source S is provided. 【0085】 Conceptually, the above can be understood as follows: If the two orthogonal reflectors 30-1 to 30-3 are formed on a flat surface at an angle greater than 0° and less than 90°, the twice-reflected light from the two orthogonal reflectors 30-1 to 30-3 will spread out without forming an image on the side where the light source is located. Therefore, by curving the surface on which the two orthogonal reflectors 30-1 to 30-3 are formed along the Y-axis towards the negative Z-axis, the twice-reflected light will be focused, and an image will be formed on the side where the light source is located. 【0086】 Figure 15 shows the case where a light ray LL incident from a light source S is reflected once by each of the two orthogonal reflectors 30-1 to 30-3, without being reflected twice, and does not exit on the same side as the light source S. As shown in Figure 15, if the light ray LL emitted from the light source S does not proceed to the second reflecting surface 32 after being incident on the first reflecting surface 31, the once reflected light LR1 reflected by the first reflecting surface 31 travels downwards to the two-plane orthogonal reflector 30. This is because the reflector rows 22 shown in Figures 1 and 3, which are arranged along the Y-axis, are spaced apart. Although not shown, the light rays LL emitted from the light source S that are not incident on either the first reflecting surface 31 or the second reflecting surface 32 travel downwards to the two-plane orthogonal reflectors 30-1 to 30-3. 【0087】 Thus, in the imaging element of this embodiment, by setting the angles Θ1 to Θ3 of the two-plane orthogonal reflectors 30-1 to 30-3 with respect to the virtual plane according to the positions of the two-plane orthogonal reflectors 30-1 to 30-3 on the Y axis, it is possible to form an image on the same side as the light source S. At the same time, by using two-plane orthogonal reflectors, light that has been reflected once or light rays that have not been reflected even once will not be imaged on the same side as the light source S. Therefore, no virtual image other than the real image is observed on the side of the light source S. Furthermore, it is possible to prevent the image from being spied on. 【0088】 The imaging element 10 in this embodiment will operate even if the position of the light source and the position of the image are swapped. Figures 16 and 17 are schematic side views illustrating the operation of the imaging element in this embodiment. In Figures 16 and 17, the configuration of the two-plane orthogonal reflectors 30-1 to 30-3, and the relationship between the two-plane orthogonal reflectors 30-1 to 30-3, the first surface 11a, and the virtual plane P0 are the same as those explained in relation to Figures 14 and 15. As shown in Figure 16, the light source S1 is positioned at the location of image I as described in relation to Figure 14, and in this case, image I1 is formed at the location of light source S as in Figure 14. The light ray LL emitted from the light source S1 is reflected twice by the two orthogonal reflectors 30-1 to 30-3, and the twice-reflected light LR2 is imaged at the location of image I1. 【0089】 As shown in Figure 17, when a light ray LL emitted from the light source S1 and incident on the two-plane orthogonal reflector 30 is reflected by the first reflective surface 31, the single reflected light LR1 may be emitted towards the first surface 11a instead of heading towards the second reflective surface 32. This single reflected light LR1 diverges and does not form an image, but it is observed as a virtual image of the light source at a different position from the light source S1. In other words, when the single reflected light reflected once by the two-plane orthogonal reflector 30 is reflected towards the first surface 11a without being reflected a second time, a real image may be formed on the side where the light source S1 is located, and a virtual image may be observed at a different position from the position where the real image is formed. In this case, the position where the real image is formed can be near the area directly above the two-plane orthogonal reflectors 30-1 to 30-3. 【0090】 The angle of the two-plane orthogonal reflector can be determined by setting the two-plane orthogonal reflector on a flat surface, then curving the flat surface along the Y-axis, and determining the angle corresponding to the curvature, as conceptually explained above, or it can be determined by other methods. The angle of the two-plane orthogonal reflector with respect to the virtual plane P0 can be set, for example, by setting the angle difference between adjacent two-plane orthogonal reflectors on the Y-axis to a predetermined value. For example, if the predetermined value is 1°, then Θ2 = Θ1 + 1° and Θ3 = Θ2 + 1° can be set. 【0091】 Regardless of the position of the light sources S and S1, the angle of the two-plane orthogonal reflector can be appropriately set using experiments or simulations to reflect the incident light ray twice and form an image at the desired position. For example, in the embodiment shown in Figure 14, the light source S is positioned almost directly above the reflector array, and in the embodiment shown in Figure 16, the position where the image I1 is formed is also positioned almost directly above the reflector array. By appropriately adjusting the angle of the two-plane orthogonal reflector with respect to the virtual plane P0, the positions of these light sources S and S1 and the images I and I1 can also be appropriately changed. When making such design changes, ray analysis tools such as ray tracing simulations can be effectively utilized. 【0092】 Figure 18 is a schematic diagram illustrating a calculation example related to the imaging element of this embodiment. The following describes how to determine the emission angle of the twice-reflected light, which is reflected twice by the two-plane orthogonal reflector of the imaging element 10 shown in Figure 1, using Figure 18. To determine the emission angle of the twice-reflected light, we utilize the fact that the corner cube reflector, as explained in relation to Figure 12A, retroreflects through its three reflective surfaces. In Figure 18, a third reflective surface of the corner cube reflector is tentatively placed and referred to as the temporary reflective surface 35a. The temporary reflective surface 35a corresponds to the third reflective surface 35, as explained in relation to Figure 12A. In the two-plane orthogonal reflector 30 shown in Figure 12B, the angle of the valley-side connecting line 33 with respect to the tangent plane is defined as the inclination of the two-plane orthogonal reflector 30. The angle of the valley-side connecting line 33 corresponds to the angle of the third reflective surface 35 of the corner cube reflector shown in Figure 12A with respect to the tangent plane. 【0093】 As shown in Figure 18, the first surface 11a is part of a circular arc with center C. Figure 18 shows the tangent plane P of the first surface 11a, and the pseudo-reflecting surface 35a is positioned at an angle φ with respect to the tangent plane P. The angle φ is approximately 60°, or more precisely, approximately 54.7°, as will be explained later in relation to Figure 19. 【0094】 The first surface 11a and the false reflection surface 35a intersect at point R2. The light ray emitted from the light source S contains the line segment SR2. The line segments SR2 and CR2 form an angle β. 【0095】 If the angle between the virtual plane P0 and the tangent plane P is angle α, then the angle between line segment CS and line segment CR2 is equal to angle α. 【0096】 If we let angle θ be the angle between line segment CR2 and the temporary reflection surface 35a, then, as will be explained later in relation to Figure 19, angle θ is approximately 30°, or more precisely, approximately 35.3°. 【0097】 Therefore, if we let the angle between the virtual plane P0 and the reflected light from the second reflection be the exit angle θ0, then this exit angle θ0 can be calculated as θ + (α - β). Here, if we set the position of the center C of the arc so that the length of line segment CS is equal to the length of line segment SR2, then α ≈ β, and the exit angle θ0 becomes approximately equal to θ, so the reflected light can be imaged. Making the length of line segment CS equal to the length of line segment SR2 is approximately equivalent to making the radius of the arc twice the length of line segment SR2. Therefore, it is preferable that the radius of the arc forming the first surface 11a be approximately twice the distance from the position of the light source S to the first surface 11a. 【0098】 Figures 19 to 21C are schematic diagrams illustrating calculation examples related to the imaging element of this embodiment. Figure 19 shows a diagram of a corner cube reflector CCR in order to calculate the angle θ of a two-plane orthogonal reflector with respect to the tangent plane P. Figures 20A and 20B show diagrams of a corner cube reflector CCR for calculating the emission angle γ with respect to the tangent plane P in a two-plane orthogonal reflector. Figures 21A to 21C show a diagram of a corner cube reflector (CCR) to illustrate that the two-plane orthogonal reflector in the imaging element of this embodiment differs from a well-known corner cube reflector. 【0099】 The left-hand diagram in Figure 19 shows a plan view of the corner cube reflector (CCR). As shown in the left diagram of Figure 19, the corner cube reflector CCR has three reflective surfaces A, B, and C. In the corner cube reflector described in relation to Figure 12A, reflective surface A corresponds to the second reflective surface 32, reflective surface B corresponds to the first reflective surface 31, and reflective surface C corresponds to the third reflective surface 35. The corner cube reflector CCR has points a to e, where points a and b are the ends of the connecting line between reflective surfaces A and B, points b and d are the ends of the connecting line between reflective surfaces A and C, and points b and e are the ends of the connecting line between reflective surfaces B and C. The corner cube reflector CCR is tangent to the tangent plane P at point b. This situation corresponds to the two-plane orthogonal reflector 30 described in relation to Figures 4A and 4B being tangent to the tangent plane P at vertex 33b. Point c is the midpoint of line segment de. In this example, reflective surfaces A, B, and C are assumed to be squares with side length 1. 【0100】 The right-hand diagram in Figure 19 shows a portion of the side view of the corner cube reflector CCR, along with the tangent plane P on which the corner cube reflector CCR is installed. Furthermore, the relationship between points a, b, c, and o is shown to correspond to the left-hand diagram in Figure 19. Points d and e coincide with point c. As shown in the right-hand figure of Figure 19, the hypothetical ade plane can be defined as a plane parallel to the tangent plane P. Therefore, the length of the line segment bc is 1 / √2. 【0101】 Let o be the point where the normal of the tangent plane P passing through point b intersects the plane ade. Since segment ac is the angle bisector of equilateral triangle ade with side length √2, the length of segment ac is √3 / √2, and therefore the length of segment co is 1 / √6. 【0102】 From the above, cosφ = co / bc = 1 / √3, so φ ≈ 54.7°. The angle θ that line segment ab makes with the tangent plane P is θ = 90° - φ ≈ 35.3°. 【0103】 In Figures 20A and 20B, the configuration of the corner cube reflector CCR is the same as in Figure 19. In the upper part of Figure 20A, for ease of explanation, the corner cube reflector CCR is shown rotated 90° clockwise from that in Figure 19. The lower part of Figure 20A shows a side view of the corner cube reflector CCR, corresponding to the positions of points a, b, and c in the upper part of Figure 20A. Looking from the direction of the arrow in Figure 20A, a reflective surface C with a side length of 1 is visible, and the diagonal length of reflective surface C is √2. In the lower part of Figure 20A, points d and e coincide with point c. Also, the ade plane is the same as the ade plane shown in Figure 19. 【0104】 As shown in Figure 20A, the plane ade is parallel to the tangent plane P. The angle between line segment bc and the tangent plane P is φ, and the angle between line segment ab and the tangent plane P is θ. 【0105】 Here, as shown in Figure 20B, if we assume that three reflected rays LR3 are emitted perpendicularly from the reflective surface C at point c, then the two reflected rays LR2 incident on the reflective surface C shown in Figure 20A will be incident at an angle β. The angle γ between the two reflected rays LR2 and the tangent plane P is γ + β = φ, where φ is approximately 54.7°, as explained in relation to Figure 19. Therefore, γ can be found as γ = 2 × φ - 90° ≈ 19.4°. Note that β = θ, and therefore β ≈ 35.3°. 【0106】 Figures 21A to 21C illustrate how the two-plane orthogonal reflector of the imaging element in this embodiment differs from a well-known corner cube reflector. Figures 21A to 21C show the shapes corresponding to the corner cube reflector CCR described in relation to Figures 19 and 20A. In Figures 21A to 21C, points a, b, d, and e correspond to points a, b, d, and e in the case of the corner cube reflector CCR related to Figures 19 and 20A. In Figures 21A to 21C, points f, g, and h are added in addition to points a, b, d, and e. The square with vertices a, h, d, and b corresponds to the second reflective surface 32 described in relation to Figures 4A and 4B. The square with vertices a, b, e, and g corresponds to the first reflective surface 31 described in relation to Figures 4A and 4B. In the two-face orthogonal reflector 30, the square with vertices b, e, f, and d corresponds to the removed reflective surface and corresponds to reflective surface C of the corner cube reflector CCR related to Figures 19 and 20A. 【0107】 In Figure 21A, the square bdfe is shown with horizontal hatching. The triangles adb and abe are shown with vertical hatching. In Figure 21B, the area corresponding to the square bdfe in Figure 21A is shown with a thick solid line. In other words, the square bdfe corresponds to the third reflective surface of the corner cube reflector. Figure 21C shows a portion of Figure 21B, along with a light ray and its reflected light. 【0108】 In the following, we consider the case where a third reflective surface exists in the square bdfe shown in Figures 21A and 21B. As shown in Figure 21C, when a light ray is incident on the square bdfe shown in Figures 21A and 21B from the positive Z-axis side, the incident light at point f is reflected at an angle β with respect to the square bdfe. As explained in relation to Figure 20B, β = θ ≈ 35.3°, and tanβ = 1 / √2. Therefore, when a reflective surface exists on the square bdfe, the reflected light is incident on either triangle adb or triangle abe, which are hatched vertically. Next, it is reflected again by either the reflective surface corresponding to square abeg or the reflective surface corresponding to square ahdb, and emitted on the positive Z-axis side. From the above, it can be said that the two-plane orthogonal reflector in the imaging element of this embodiment differs from the corner cube reflector. 【0109】 As described above, the imaging element of this embodiment can form an image on the first surface 11a by reflecting twice the light rays emitted from a light source provided on the first surface 11a side with respect to the substrate 12 using a two-plane orthogonal reflector. 【0110】 The effects of the imaging element 10 in this embodiment will be described. In the imaging element 10 of this embodiment, the angle of the two-plane orthogonal reflector 30 with respect to the virtual plane P0 is set to be greater than 0° and less than 90°. Furthermore, the angle of the two-plane orthogonal reflector 30 with respect to the virtual plane P0 is set differently depending on the position in which the two-plane orthogonal reflector 30 is positioned in the Y-axis direction. The angle is set to be larger as the distance from the two-plane orthogonal reflector 30 at the reference position is in one direction in the Y-axis direction, and smaller as the distance is in the other direction in the Y-axis direction. By setting it in this way, when the substrate 12 is used as a reference, the light rays from the first surface 11a side are reflected twice and an image is formed on the first surface 11a side. 【0111】 In the imaging element 10 of this embodiment, by appropriately setting the angle of the two-plane orthogonal reflector 30 with respect to the virtual plane P0, the light source can be placed at any position on the first surface 11a side with respect to the substrate 12, and an image can be formed at any desired position on the first surface 11a side that is different from the light source. 【0112】 As explained in the first to fourth modifications, if the angle of the two-plane orthogonal reflector 30 with respect to the virtual plane P0 can be appropriately set, an optimally shaped imaging element can be realized by forming a reflector array on a substrate of any shape. Therefore, a substrate of any shape can be appropriately selected and applied according to the size, location, and method of housing the imaging element, making it easier to achieve miniaturization and simplification of the device structure. 【0113】 As explained in the fifth modification, the shapes of the first and second reflective surfaces can also be rectangular, not just square, when viewed from the front, thereby realizing an imaging element with improved image brightness. Furthermore, by optimally setting the ratio between the spacing of the reflector rows 22 and the area of ​​the reflective surfaces, it becomes possible to obtain images with even higher brightness. 【0114】 (Second embodiment) The image display device described below uses an imaging element that utilizes the reversibility of reflection of a two-plane orthogonal reflector 30, as described in relation to Figure 4D. In the following specific example, for example, the image display device forms an image according to the operation of the imaging element described in relation to Figures 16 and 17. In the following specific example, the case in which the imaging element 310, a third modification of the first embodiment described in relation to Figure 9A, is applied will be described. Unless otherwise specified, the imaging element 10 of the first embodiment or other modified imaging elements 110, 210, 210a, and 310a may be applied to the image display device described below. 【0115】 Figure 22 is a schematic side view illustrating an image display device according to this embodiment. As shown in Figure 22, the image display device 1000 of this embodiment comprises an imaging element 310 and a display device 1001. In Figure 22, the imaging element 310 includes a substrate 312 and a reflector array 20. The reflector array 20 is provided on the first surface 311a of the substrate 312. The reflector array 20 is inclined with respect to the first surface 311a, and this inclination is set to gradually increase or decrease along the Y-axis, as shown in Figure 9A. In Figure 22 and the figures described later, the dashed line represents the envelope connecting the vertices 33a of the two-plane orthogonal reflector 30 shown in Figure 4B. In the reflector array 20 of Figure 22, three two-plane orthogonal reflectors 30 are shown in a simplified form from among many two-plane orthogonal reflectors, so that the reflection of light rays incident on the reflector array 20 can be seen. 【0116】 In this example, a display device (first display device) 1001 is provided as a light source. The display device 1001 displays an image (first image), including moving images and still images. The display device 1001 can be various output devices capable of displaying images. For example, the display device 1001 can be a display device with semiconductor light-emitting elements as pixels. The display device 1001 including semiconductor light-emitting elements includes a substrate 1002 and a plurality of semiconductor light-emitting elements 1004. The plurality of semiconductor light-emitting elements 1004 are provided on the substrate 1002. The plurality of semiconductor light-emitting elements 1004 are, for example, an array of micro-LEDs formed from ultra-small inorganic semiconductor light-emitting elements, or an array of micro-OLEDs formed from organic semiconductor light-emitting elements. The display device 1001 may also utilize a liquid crystal display panel or the like. A drive circuit and control circuit, etc., for lighting the semiconductor light-emitting elements 1004 and controlling the display of images are provided, for example, within the display device 1001. The drive circuit and control circuit, etc., for the display device 1001 may be housed in a control device separate from the display device 1001. The imaging element 310 is composed of an optical reflective system and does not include a lens, so it does not cause color separation due to chromatic aberration of the emission wavelength. Therefore, the display device 1001 can be a color image display device that displays a clear color image. 【0117】 The display device 1001 is located on the first surface 311a side. By using such a display device 1001 as the light source, the image display device 1000 can project images of videos, still images, etc., displayed on the display device 1001 into the air. An observer viewing the image on the image display device 1000 will observe the projected image I floating almost directly above the reflector array 20 from above the reflector array 20. 【0118】 If we consider each semiconductor light-emitting element 1004 constituting the display device 1001 as a point light source, then the light emitted from one semiconductor light-emitting element 1004 is thought to contain multiple rays. Figure 22 shows the rays emitted from one semiconductor light-emitting element 1004. 【0119】 The display device 1001 is positioned directly above the reflector array 20, offset to the negative side of the Y-axis. The solid line representing the light ray LL is a portion of the light emitted from the display device 1001. These light rays LL are reflected by the two reflective surfaces of the two-plane orthogonal reflector and emitted from the reflector array 20 as twice-reflected light LR2. 【0120】 The double-reflected light LR2 emitted from the reflector array forms an image I directly above the reflector array 20. Directly above the reflector array 20 is the position in the direction normal to the virtual plane P0 and in the positive direction of the Z axis. The ray LL' shown by the dashed line is another portion of the ray emitted from the display device 1001. These rays LL' are reflected by one of the reflecting surfaces of the two-plane orthogonal reflector 30 and emitted from the reflector array 20 as single-reflected light LR1. The single-reflected light LR1 emitted from the reflector array diverges without forming an image on the first surface 311a side. 【0121】 The virtual plane P0 is a plane that is substantially parallel to the first surface 311a. If the base material 312 is made of a translucent material, the reflector array 20 may be provided on the second surface 311b of the base material 312. In this case, the second surface 311b of the base material 312 is substantially parallel to the virtual plane P0. 【0122】 Regarding the definition of the virtual plane P0 when applying the imaging element of the first embodiment or other modified examples to the image display device of this embodiment, it has already been explained in relation to Figure 2. 【0123】 Although not shown in the figures, some light rays emitted from the display device 1001 are not reflected even once by the two-plane orthogonal reflector. If the substrate 312 is translucent, the light rays that are not reflected even once pass through the gaps 23 in the reflector rows 22 and the base 36 shown in Figure 1 to the second surface 311b. When the modified substrate described in relation to Figures 10A to 10C is applied to the imaging element, the light rays that are not reflected even once are absorbed by the light absorbers provided in the gaps 23 in the reflector rows 22. 【0124】 Thus, in the image display device 1000 of this embodiment, a virtual image may be formed at a location other than directly above the reflector array 20, and if this is visible to the user of the image display device 1000, it may appear as a ghost image. A virtual image caused by a single reflected light can be formed at a location sufficiently far from the image formation position by appropriately setting the arrangement of the display device 1001 and the angle of the two-plane orthogonal reflector 30 that constitute the reflector array 20. When the imaging element 310 is housed in a housing, the virtual image can be prevented from being observed by applying black paint or the like to the inner wall of the housing to give it light-absorbing properties. 【0125】 (modified version) Figure 23 is a schematic plan view illustrating a part of the image display device according to this modified example. Figure 23 shows a schematic plan view of the substrate 312a. The substrate 312a can be applied to replace the substrate 312 of the image display device 1000 shown in Figure 22. The imaging element to which the substrate 312a is applied may be applied to the second and third modifications of the second embodiment described later. 【0126】 The substrate 312a has a light-reflecting band 816 formed on the first surface 311a. The light-reflecting band 816 is located in the region between the reflector rows 22 shown in Figures 1 and 3. The light-reflecting band 816 can be, for example, a thin film of the same metallic material as the two reflective surfaces that make up the two-plane orthogonal reflector 30. 【0127】 In the image display device 1000 of the second embodiment shown in Figure 22, light rays that are not reflected even once by the two-plane orthogonal reflector 30 are incident on the region between the reflector rows 22. Even if light rays that are not reflected even once by the reflector array 20 are reflected by the light reflection band 816, the reflected light is emitted in a direction different from the position of image formation I according to the law of reflection and does not affect image formation I. It should be noted that regardless of the configuration of the reflector array 20 described in relation to Figures 3A to 3C, even if the spacing 23 or the base 36 is made of light reflector, light rays that are not reflected even once by the two-plane orthogonal reflector 30 do not affect image formation I. 【0128】 When the entire surface of the imaging element 310 is formed from a light-reflective material together with the two reflective surfaces of the two-plane orthogonal reflector to form the light-reflecting band 816, the manufacturing process of the imaging element 310 can be simplified, and productivity can be improved. 【0129】 The operation of the image display device 1000 of this embodiment will now be described. Figure 24A is a schematic plan view illustrating the operation of the image display device of this embodiment. Figure 24B is a schematic side view illustrating the operation of the image display device of this embodiment. In the image display device 1000 of this embodiment, the imaging element 10 of the first embodiment is used, so the imaging element 310 operates as described in relation to Figures 16 and 17. In this embodiment, a portion of the light rays incident on the imaging element 310 from the display device 1001 provided on the first surface 311a side is reflected twice by the two-plane orthogonal reflector and emitted back to the first surface 311a side to form an image. The other portion of the light rays incident on the imaging element 310 is emitted as light reflected once by the two-plane orthogonal reflector, and a virtual image may be formed on the first surface 311a side at a position different from the imaging position. 【0130】 As shown in Figures 24A and 24B, a light ray incident on the imaging element 310 from a display device 1001 located on the first surface 311a side, offset in the Y-axis direction from directly above the reflector array 20, is reflected twice by the two-plane orthogonal reflector and is imaged in region R1 on the first surface 311a side, directly above the reflector array 20. The Z-axis and Y-axis lengths of region R1 are determined by the angle of the two-plane orthogonal reflector with respect to the virtual plane P0 and by the adjustment or setting of the position of the display device 1001. The position of the display device 1001 can be set to a Y-axis position sufficiently farther away from the Y-axis position of the imaging position. The imaging region R1 can be set to a high position sufficiently farther away from the reflector array 20 in the positive Z-axis direction, or to a closer position. 【0131】 In this example, the virtual plane P0 is approximately parallel to the first surface 311a. However, as in the first embodiment, if the first surface is a curved surface, the virtual plane P0 is the tangent plane at the lowest position in the Z-axis direction of the arc of the first surface and part of the arc of the reflector array 20. In this case, the lengths in the Z-axis direction of both ends of the imaging element in the Y-axis direction are also approximately equal, as in the first embodiment. In this case, if the incident light ray is reflected twice by the two orthogonal reflectors and emitted towards the first surface, the position of the virtual plane P0 is not limited to the above and may be arbitrary. 【0132】 The reflected light emitted from the display device 1001 and reflected once by the reflector array 20 may form a virtual image in region R2, which is on the first surface 311a side and shifted in the Y-axis direction from the image-forming region R1. In this example, the region R2 where the virtual image due to the once-reflected light can be observed is located on the positive Y-axis side of both the display device 1001 and the reflector array 20. Region R2 is determined by the angle of the two-plane orthogonal reflector with respect to the virtual plane P0, and by the adjustment and setting of the position of the display device 1001. For example, region R2 may be on the first surface 311a side and on the display device 1001 side of the reflector array 20. 【0133】 The effects of the image display device 1000 of this embodiment will be described. In reflective image display devices using an imaging element with a two-plane orthogonal reflector, it is difficult to form an image directly above the imaging element (see, for example, Patent Document 1). Therefore, it is difficult to superimpose the image formation position and the position of the imaging element in an XY plane view. 【0134】 In image display devices using corner cube reflectors as imaging elements, as explained in relation to Figure 12A, the corner cube reflector is a retroreflective element (see, for example, Patent Document 2). Therefore, in order to make the position of imaging and the position of the light source different, it is necessary to use optical elements such as half mirrors to separate the optical path, which complicates the structure of the device and tends to make the device larger. 【0135】 In the image display device 1000 of this embodiment, the two-plane orthogonal reflector is configured such that a portion of the light emitted from the light source, which is reflected once by one reflective surface, is reflected by the other reflective surface and emitted as double-reflected light. Therefore, as in this example, when the light source is the display device 1001, the image display device 1000 of this embodiment can display videos and still images output by the display device 1001 in the air with a simple structure. 【0136】 In the image display device 1000 of this embodiment, by appropriately setting the angle of the two-plane orthogonal reflector with respect to the virtual plane P0, the two-plane orthogonal reflector emits twice reflected light directly above the imaging element 310. Directly above the imaging element 310 is in the direction normal to the virtual plane P0 and in the positive direction of the Z axis. 【0137】 For example, the display device 1001, which is a light source, is positioned offset in the Y direction from directly above the imaging element 310, where the reflector rows are arranged. By appropriately setting the angle of the two-plane orthogonal reflector 30, the image display device 1000 can form an image I directly above the imaging element 310. 【0138】 Thus, the image display device 1000 of this embodiment can form an image I directly above the reflector array 20. Therefore, as will be explained in the third and fourth embodiments described later, it becomes possible to easily configure an image display device with high decorative and design qualities. 【0139】 The display device 1001, which serves as a light source, uses a semiconductor light-emitting element 1004, for example, In X Al Y Ga 1-X-Y The gallium nitride-based compound semiconductor element can include a light-emitting layer such as N(0≦X, 0≦Y, X+Y<1). By processing such a gallium nitride-based compound semiconductor element into a micro-LED element and forming it on the substrate 1002, it becomes possible to display images with high contrast. Therefore, the image display device 1000 of this embodiment can display clearer images in the air. 【0140】 In this embodiment, as a specific example, a flat substrate 312 is used as the imaging element 310, making it possible to create a thin imaging element 310 and thus a compact image display device 1000. By applying the imaging elements of the first embodiment and its modified forms described above to an image display device, an image display device can be created that is tailored to the characteristics of each imaging element. 【0141】 (Third embodiment) Figure 25 is a schematic side view illustrating an image display device according to this embodiment. In this embodiment, the image display device 1100 differs from the second embodiment described above in that it includes a decorative panel 1102. In other respects, it is the same as the second embodiment, and the same reference numerals are used for the same components, and detailed descriptions are omitted. As shown in Figure 25, the image display device 1100 comprises a display device 1001, an imaging element 310, and a decorative panel 1102. The configuration of the display device 1001 and the imaging element 310 is the same as in the second embodiment, and a detailed description is omitted. As in the second embodiment, the imaging element of the first embodiment or a modified version thereof can be used. 【0142】 The decorative panel 1102 is provided on the first surface 311a side. The decorative panel 1102 is provided at a predetermined distance from the imaging element 310 and covers the imaging element 310. 【0143】 Light rays emitted from the display device 1001 are reflected twice by the two-plane orthogonal reflectors 30 that constitute the reflector array 20, and are emitted from the reflector array 20 as double-reflected light LR2. The double-reflected light LR2 emitted from the reflector array 20 forms an image I directly above the two-plane orthogonal reflectors 30 via the decorative panel 1102. The decorative panel 1102 is provided between the reflector array 20 and the image I. In this example, the decorative panel 1102 is provided between the reflector array 20 and the display device 1001, but the display device 1001 only needs to be able to irradiate the reflector array 20 with light, and may be positioned closer to the reflector array 20 than the decorative panel 1102 in the Z-axis direction. Alternatively, the decorative panel 1102 may not be provided between the reflector array 20 and the display device 1001. 【0144】 The decorative panel 1102 is a frame-shaped panel member, and its frame portion is decorated. The area surrounded by the frame portion has a low haze value and light transmittance, and transmits the twice reflected light from the reflector array 20. A low haze value is desirable, for example, 20% or less, and more preferably 5% or less. For example, the frame portion of the decorative panel 1102 is decorated with a wood grain pattern on the surface where the car's speedometer is installed. When the display device 1001 displays an image representing the speedometer, the image is formed through the decorative panel 1102, and to the user, it appears as if the speedometer is installed on a wood grain instrument panel. 【0145】 The decorative panel 1102 is formed from a material with sufficient light transmittance so that the area enclosed by the frame portion of the decorative panel 1102 can transmit reflected light twice. 【0146】 Regarding the decorative panel 1102, a pattern may be applied to the translucent area surrounded by the frame. For example, a fixed display pattern can be applied to the area surrounded by the frame. A fixed display pattern is, for example, the dial of a car's speedometer. An arbitrary pattern, such as a wood grain pattern, may be applied to the translucent area surrounded by the frame, and the image display device 1100 may display a video of a speedometer or the like. In such a case, when the image display device 1100 is not displaying an aerial image, it will appear as a wood grain panel, and when the image display device 1100 is displaying an aerial image, the speedometer can be displayed in front of this wood grain panel. By making an arbitrary pattern such as a speedometer dial or a wood grain pattern the fixed display pattern of the decorative panel 1102, the image display device 1100 can provide the user with a sufficient amount of information while keeping the data for the aerial image output by the image display device 1100 to a small size. 【0147】 In this way, by adding the decorative panel 1102, the amount of information displayed by the image display device 1100 as a whole can be increased. The decorative panel 1102 can be selected in various ways depending on the application of the image display device 1100, so that high decorative and design qualities can be expressed. In Figure 25, the light rays emitted from the display device 1001 are depicted as reaching the reflector array 20 via the decorative panel 1102. If the frame portion of the decorative panel 1102 is in the optical path of the light rays emitted from the display device 1001, the amount of light reaching the reflector array 20 will decrease, or the design of the corresponding part of the frame portion will be removed as necessary to suppress interference between the design of the frame portion and the emitted light. Alternatively, the brightness of the aerial display in the area blocked by the decorative panel 1102 may be partially increased. In that case, appropriate measures such as partially increasing the brightness of the light emitted from the display device 1001 will be taken according to the shape and pattern of the decorative panel 1102. 【0148】 The effects of the image display device 1100 of this embodiment will be described. In reflective image display devices using two-plane orthogonal reflectors as imaging elements, or in image display devices using corner cube reflectors as imaging elements, in order to give the image a decorative effect, it is necessary to additionally place decorative elements at positions different from the imaging elements. Therefore, an increase in the overall size of the device is unavoidable. 【0149】 In the image display device 1100 of this embodiment, the decorative panel 1102 is provided on the first surface 311a side. The imaging element 310 can form an image in the air directly above it, similar to the case of the second embodiment described above. Since the image formed in the air is formed by passing through the translucent region of the decorative panel 1102, an observer at the position where the image is formed will see the airborne image as being formed in the region on the decorative panel 1102. Therefore, an image display device with high decorative and design qualities can be easily realized without complicating the structure of the device or increasing its size. 【0150】 (Fourth embodiment) Figure 26 is a schematic side view illustrating an image display device according to this embodiment. In this embodiment, the image display device 1200 differs from that of the second embodiment described above in that it includes a display panel 1202. In other respects, it is the same as that of the second embodiment, and the same reference numerals are used for the same components, and detailed descriptions are omitted. As shown in Figure 26, the image display device 1200 comprises a display device 1001, an imaging element 310, and a display panel (second display device) 1202. The configuration of the display device 1001 and the imaging element 310 is the same as in the second embodiment, and a detailed explanation is omitted. As in the second embodiment, the imaging element of the first embodiment and modified imaging elements thereof can be used. 【0151】 The display panel 1202 is provided on the second surface 311b side. The imaging element 310 is provided on the display panel 1202. In this example, since the imaging element 310 uses a flat substrate 312, the flat display panel 1202 is provided in close contact with the second surface 311b. When the imaging element uses a substrate with a curved surface, as in the first embodiment, the display panel is pre-curved, for example, to form part of an arc that is convex in the negative direction of the Z axis in a YZ plan view. The display panel 1202 may be made of a flexible material, in which case the display panel is curved and brought into close contact with the mounting surface of the imaging element. 【0152】 The display panel 1202, although not shown in the diagram, includes not only a panel for displaying images, but also control circuits and drive circuits for controlling the display of videos and still images on the panel. The control circuits and drive circuits are, for example, located on the negative Z-axis side of the display panel 1202. The display panel 1202 displays videos and still images in the positive Z-axis direction according to the operation of the control circuits and drive circuits. The drive circuits and control circuits for the display panel 1202 may be housed in a control device in a separate enclosure from the display panel 1202. 【0153】 The videos and still images displayed on the display panel 1202 are displayed independently of the images displayed on the display device 1001. Alternatively, the videos and still images displayed on the display panel 1202 are displayed in conjunction with the images displayed on the display device 1001. For example, the videos and still images displayed on the display panel 1202 are displayed as the background for the image formed by the image displayed on the display device 1001. Specifically, the images displayed on the display panel 1202 are, for example, images of characters from games or anime. 【0154】 In this embodiment, each modification can be combined as appropriate. For example, the decorative panel 1102 in the third embodiment may be provided so as to display both the image displayed by the display panel 1202 in this embodiment and the image displayed in the air by the display device 1001. 【0155】 The effects of the image display device 1200 of this embodiment will be described. The image display device 1200 of this embodiment is equipped with a display panel 1202 on the back of the imaging element 310. By equipping the image display device 1200 with a display panel 1202 on the back of the imaging element 310, the image produced by the imaging element 310 can be displayed in mid-air, superimposed on the video or still image displayed by the display panel 1202. As a result, users can view a large amount of information, and the image display device 1200 can achieve high decorative and design qualities, as well as function as an advanced information processing terminal. 【0156】 According to the embodiments described above, an image display device capable of displaying images in mid-air with a simple structure can be realized. 【0157】 Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. Furthermore, the embodiments described above can be implemented in combination with each other. 【0158】 The embodiments include the following aspects: 【0159】 (Note 1) Image-forming element and, A light source that illuminates the imaging element with light, Equipped with, The aforementioned imaging element is A substrate having a first surface and a second surface located opposite the first surface, and a reflector array provided on the substrate, The reflector array includes a plurality of reflector rows, each containing a plurality of two-plane orthogonal reflectors arranged along a first direction. Each of the plurality of two-sided orthogonal reflectors includes a first reflective surface provided to reflect light from the side of the first surface, and a second reflective surface provided perpendicular to the first reflective surface and provided to reflect the light reflected from the first reflective surface back towards the first surface. In each of the plurality of reflector rows, the angle between the line where the first reflective surface and the second reflective surface intersect, and the virtual plane including the first direction and the second direction intersecting the first direction, is set to a value greater than 0° and less than 90°. The angle between the first reflective surface and the virtual plane is set to a value greater than 45° and less than 90°. The plurality of reflector rows include a first reflector row among the plurality of reflector rows in which the angle between the straight line and the virtual plane is set to the smallest value. Of the plurality of reflector rows, the angle between the line and the virtual plane of the remaining reflector row is set to a value that increases as it moves away from the first reflector row in the second direction. The light source is provided on the first surface side, Each of the plurality of two-plane orthogonal reflectors is provided in an image display device such that a portion of the light emitted from the light source and reflected once by the first reflecting surface travels toward the second reflecting surface. 【0160】 (Note 2) Each of the plurality of two-plane orthogonal reflectors is provided such that a portion of the once reflected light is reflected by the second reflecting surface and propagates in the third direction. The third direction is the image display device described in Appendix 1, which is orthogonal to the first and second directions. 【0161】 (Note 3) The system further comprises a translucent decorative panel covering the reflector array, The image display device according to Appendix 1 or 2, wherein the twice-reflected light reflected by the second reflective surface is emitted from the reflector array via the decorative panel. 【0162】 (Note 4) The light source is a first display device capable of displaying a first image, The first display device is an image display device according to any one of the appendices 1 to 3, comprising a substrate and a plurality of semiconductor light-emitting elements provided on the substrate. 【0163】 (Note 5) The image display device according to any one of the appendices 1 to 4, wherein the substrate is a light-transmitting material. 【0164】 (Note 6) In the substrate, the first surface is a plane parallel to the virtual plane. The reflector array is an image display device according to any one of appendices 1 to 5 provided on the first surface. 【0165】 (Note 7) The aforementioned substrate is light-transmitting, In the substrate, the second surface is a plane parallel to the virtual plane. The reflector array is an image display device according to any one of appendices 1 to 5 provided on the second surface. 【0166】 (Note 8) In the substrate, the first surface is provided such that, in a plan view including the second and third directions, it is convex toward the side of the second surface. The third direction is perpendicular to the first and second directions, The reflector array is provided on the first surface, The image display device described in any one of the appendices 1 to 5, wherein the angles of the angles between the straight lines and the first surface of the plurality of reflector rows are set to equal values. 【0167】 (Note 9) The aforementioned substrate is light-transmitting, The second surface is provided such that, in a plan view including the second and third directions, it is convex from the side of the first surface. The third direction is perpendicular to the first and second directions, The reflector array is provided on the second surface, The image display device described in any one of the appendices 1 to 5, wherein the angles of the angles between the straight lines and the second surface of the plurality of reflector rows are set to equal values. 【0168】 (Note 10) The image display device according to any one of appendices 1 to 9, further comprising a protective layer provided so as to cover the reflector array. 【0169】 (Note 11) The image display device according to any one of appendices 1 to 10, further comprising a light-reflective member between adjacent reflector rows among the plurality of reflector rows. 【0170】 (Note 12) The image display device according to any one of the appendices 1 to 10, further comprising a light-absorbing member between adjacent reflector rows among the plurality of reflector rows. 【0171】 (Note 13) The system further includes a second display device capable of displaying a second image, The aforementioned substrate is light-transmitting, The imaging element is an image display device according to any one of appendices 1 to 10, provided on the second display device. [Explanation of Symbols] 【0172】 10,110,210,210a,310,310a Imaging elements, 11a,211a,311a,611a First surface, 11b,111b,211b,311b,611b Second surface, 12,112,212,212a,312,612 Substrate, 20 Reflector array, 22,722 Reflector row, 30,730 Two-plane orthogonal reflector, 31,731 First reflective surface, 32,732 Second reflective surface, 33 Valley side connection line, 1000,1100,1200 Image display device, 1001 Display device, 1002 Substrate, 1004 Semiconductor light-emitting element, 1102 Decorative panel, 1202 Display panel, S,S1 Light source, P0 Virtual plane

Claims

[Claim 1] Image-forming element and, A light source that illuminates the imaging element with light, Equipped with, The imaging element is A substrate having a first surface and a second surface located opposite the first surface, and a reflector array provided on the substrate, The reflector array includes a plurality of reflector rows, each containing a plurality of two-plane orthogonal reflectors arranged along a first direction. Each of the plurality of two-sided orthogonal reflectors includes a first reflective surface provided to reflect light from the side of the first surface, and a second reflective surface provided perpendicular to the first reflective surface and provided to reflect the light reflected from the first reflective surface back towards the first surface. In each of the plurality of reflector rows, the angle between the line where the first reflective surface and the second reflective surface intersect, and the virtual plane including the first direction and the second direction intersecting the first direction, is set to a value greater than 0° and less than 90°. The angle between the first reflective surface and the virtual plane is set to a value greater than 45° and less than 90°. The plurality of reflector rows include a first reflector row among the plurality of reflector rows in which the angle between the straight line and the virtual plane is set to the smallest value. Of the plurality of reflector rows, the angle between the line and the virtual plane of the remaining reflector row is set to a value that increases as it moves away from the first reflector row in the second direction. The light source is provided on the first surface side, Each of the plurality of two-plane orthogonal reflectors is provided in an image display device such that a portion of the light emitted from the light source and reflected once by the first reflecting surface travels toward the second reflecting surface. [Claim 2] Each of the plurality of two-plane orthogonal reflectors is provided such that a portion of the once reflected light is reflected by the second reflecting surface and propagates in the third direction. The image display device according to claim 1, wherein the third direction is orthogonal to the first direction and the second direction. [Claim 3] The system further comprises a translucent decorative panel covering the reflector array, The image display device according to claim 1, wherein the twice-reflected light reflected by the second reflective surface is emitted from the reflector array via the decorative panel. [Claim 4] The light source is a first display device capable of displaying a first image, The image display device according to claim 1, wherein the first display device includes a substrate and a plurality of semiconductor light-emitting elements provided on the substrate. [Claim 5] The image display device according to claim 1, wherein the substrate is a light-transmitting material. [Claim 6] In the substrate, the first surface is a plane parallel to the virtual plane. The image display device according to claim 1, wherein the reflector array is provided on the first surface. [Claim 7] The aforementioned substrate is light-transmitting, In the substrate, the second surface is a plane parallel to the virtual plane. The image display device according to claim 1, wherein the reflector array is provided on the second surface. [Claim 8] In the substrate, the first surface is provided such that, in a plan view including the second and third directions, it is convex toward the side of the second surface. The third direction is perpendicular to the first and second directions, The reflector array is provided on the first surface, The image display device according to claim 1, wherein the angles of the angles between the straight lines and the first surface of the plurality of reflector rows are set to equal values. [Claim 9] The aforementioned substrate is light-transmitting, The second surface is provided such that, in a plan view including the second and third directions, it is convex from the side of the first surface. The third direction is perpendicular to the first and second directions, The reflector array is provided on the second surface, The image display device according to claim 1, wherein the angles of the angles between the straight line and the second surface of the plurality of reflector rows are set to equal values. [Claim 10] The image display device according to claim 1, further comprising a protective layer provided so as to cover the reflector array. [Claim 11] The image display device according to any one of claims 1, further comprising a light-reflective member between adjacent reflector rows among the plurality of reflector rows. [Claim 12] The image display device according to any one of claims 1, further comprising a light-absorbing member between adjacent reflector rows among the plurality of reflector rows. [Claim 13] The system further includes a second display device capable of displaying a second image, The aforementioned substrate is light-transmitting, The image display device according to claim 1, wherein the imaging element is provided on the second display device.

Images