Aerial image display apparatus

Abstract

To improve the display quality of an aerial image.SOLUTION: An aerial image display apparatus comprises: a display device 10 that displays an image; an optical control element 40 that is arranged so as to receive light from the display device 10 and transmits part of the light from the display device 10; and an optical element 50 that is arranged so as to receive the light from the optical control element 40, reflects the light from the optical control element 40 to a side opposite to the display device 10, and forms an aerial image in air. The optical control element 40 includes a plurality of transparent members 43 and a plurality of light-shielding members 44, which are alternately arranged, and the plurality of transparent members 43 and the plurality of light-shielding members 44 are inclined at a first angle with respect to the normal of the display device 10. The luminance of the display device 10 at the first angle is 60% or more of the front luminance of the display device 10.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Research is being conducted into aerial image display devices that can display images and videos as mid-air, and they are expected to serve as a new human-machine interface. Aerial image display devices use an imaging element to reflect light emitted from the display surface of a display device that displays the image, forming a real image in mid-air. The display device used is, for example, a liquid crystal display device.

[0003] In order to reduce power consumption, display devices have high brightness in the normal direction (front direction) of the display surface. Brightness in the front direction of a display device becomes unnecessary light that does not contribute to the formation of an aerial image. If there is a lot of unnecessary light that does not contribute to the formation of an aerial image, a ghost will appear near the aerial image. Therefore, it is desirable to reduce the light components that do not contribute to the formation of an aerial image. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-11501 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention provides an aerial image display device that can improve the display quality of an aerial image. [Means for solving the problem]

[0006] According to a first aspect of the present invention, there is provided a display device that displays an image, a light control element that is arranged to receive light from the display device and transmits a portion of the light from the display device, and an optical element that is arranged to receive light from the light control element and reflects the light from the light control element to an opposite side of the display device and forms an aerial image in the air, the light control element including a plurality of transparent members and a plurality of light blocking members that are alternately arranged, the plurality of transparent members and the plurality of light blocking members being inclined at a first angle with respect to a normal to the display device, the optical element including a planar base and a plurality of optical elements that are provided under the base and extend in a first direction and are perpendicular to the first direction. and a plurality of optical elements arranged in a second direction intersecting the first angle, each of the plurality of optical elements having an incident surface and a reflective surface that are inclined with respect to the normal direction of the substrate and are in contact with each other, the incident surface is arranged to receive light from the display device, the angle of the incident surface with respect to the normal direction of the substrate is set so that the incident angle of light from the light control element is smaller than the critical angle, and the angle of the reflective surface with respect to the normal direction of the substrate is set so that the incident angle of light from the incident surface is larger than the critical angle, and the brightness of the display device at the first angle is 60% or more of the front brightness of the display device.

[0007] According to a second aspect of the present invention, there is provided a display device that displays an image, a light control element that is arranged to receive light from the display device and transmits a portion of the light from the display device, and an optical element that is arranged to receive light from the light control element and reflects the light from the light control element to an opposite side of the display device and forms an aerial image in the air, wherein the light control element includes a plurality of transparent members and a plurality of light blocking members that are alternately arranged, the plurality of transparent members and the plurality of light blocking members being inclined at a first angle with respect to a normal to the display device, and the optical element includes a planar base and a plurality of optical elements that are provided under the base and extend in a first direction and are perpendicular to the first direction. and a plurality of optical elements arranged in a second direction intersecting the first direction, each of the plurality of optical elements having an incident surface and a reflecting surface that are inclined with respect to the normal direction of the substrate and are in contact with each other, the incident surface is arranged to receive light from the display device, the angle of the incident surface with respect to the normal direction of the substrate is set so that the incident angle of light from the light control element is smaller than the critical angle, the angle of the reflecting surface with respect to the normal direction of the substrate is set so that the incident angle of light from the incident surface is larger than the critical angle, and a third direction in which the plurality of transparent members and the shading member extend is set obliquely with respect to the first direction.

[0008] According to a third aspect of the present invention, there is provided an aerial image display device according to the first or second aspect, wherein the display device includes an illumination element that emits light, and a display panel that is arranged to receive light from the illumination element and displays the image.

[0009] According to a fourth aspect of the present invention, there is provided an aerial image display device according to the third aspect, wherein the lighting element includes only one prism sheet that concentrates light, and the prism sheet includes a plurality of prisms each extending in the second direction.

[0010] According to a fifth aspect of the present invention, there is provided the aerial image display device according to the fourth aspect, wherein the plurality of prisms are arranged to face upward.

[0011] According to a sixth aspect of the present invention, there is provided the aerial image display device according to the fourth aspect, wherein the plurality of prisms are arranged to face downward.

[0012] According to a seventh aspect of the present invention, there is provided the aerial image display according to the third aspect, wherein the lighting element does not have a prism sheet.

[0013] According to an eighth aspect of the present invention, there is provided an aerial image display device according to the third aspect, wherein the lighting element includes a light source unit and a light guide plate, and the light source unit is arranged on one side of the light guide plate in the second direction.

[0014] According to a ninth aspect of the present invention, there is provided the aerial image display device according to the first or second aspect, wherein the display device is configured as a self-luminous display device including an organic EL.

[0015] According to a tenth aspect of the present invention, there is provided the aerial image display device according to the first or second aspect, further comprising a diffusion layer disposed between the display device and the light control element, for diffusing light.

[0016] According to an eleventh aspect of the present invention, there is provided the aerial image display device according to the first or second aspect, wherein the display device and the light control element are arranged with a distance therebetween.

[0017] According to a twelfth aspect of the present invention, there is provided the aerial image display device according to the first or second aspect, further comprising an anti-reflection layer provided on the optical element side of the light control element.

[0018] According to a thirteenth aspect of the present invention, there is provided the aerial image display device according to the first or second aspect, further comprising an anti-reflection layer provided on the display device side of the light control element.

[0019] According to a fourteenth aspect of the present invention, there is provided the aerial image display device according to the first or second aspect, further comprising an anti-reflection layer provided on the light control element side of the display device.

[0020] According to a 15th aspect of the present invention, there is provided the aerial image display device according to the first or second aspect, wherein the optical element is configured to form the aerial image parallel to the display device. [Effects of the Invention]

[0021] According to the present invention, it is possible to provide an aerial image display device that can improve the display quality of an aerial image. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a perspective view of the main parts of an aerial image display device according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a side view of the aerial image display device according to the first embodiment. [Figure 3] FIG. 3 is a perspective view of a prism sheet included in the lighting device. [Figure 4A] FIG. 4A is a plan view of the light control element shown in FIG. [Figure 4B] FIG. 4B is a cross-sectional view of the light control element taken along line AA′ in FIG. 4A. [Figure 5] FIG. 5 is a perspective view of the optical element shown in FIG. [Figure 6] FIG. 6 is a perspective view illustrating how light is reflected in an optical element. [Figure 7] FIG. 7 is a side view of the XZ plane illustrating how light is reflected in the optical element. [Figure 8] FIG. 8 is a side view of the YZ plane illustrating how light is reflected in the optical element. [Figure 9] FIG. 9 is a diagram illustrating the angular conditions of the incident surface and the reflecting surface in the optical element. [Figure 10] FIG. 10 is a schematic plan view of the display device. [Figure 11] FIG. 11 is a diagram illustrating the luminance of the display device along the line BX-BX' in FIG. [Figure 12] FIG. 12 is a diagram illustrating the luminance of the display device along the line BY-BY′ in FIG. [Figure 13] FIG. 13 is a diagram illustrating the brightness of light emitted from the display device. [Figure 14] FIG. 14 is a diagram illustrating the light emission characteristics of the display device. [Figure 15] FIG. 15 is a diagram illustrating the brightness of an aerial image formed by the aerial image display device. [Figure 16] FIG. 16 is a diagram illustrating visual evaluation of an aerial image according to the distance between the display device and the light control element. [Figure 17] FIG. 17 is a schematic diagram illustrating the effect of reducing moire in an aerial image. [Figure 18] FIG. 18 is a side view of an aerial image display device according to a modified example. [Figure 19] FIG. 19 is a side view of an aerial image display device according to the second embodiment of the present invention. [Figure 20] FIG. 20 is a perspective view of the main parts of an aerial image display device according to the third embodiment of the present invention. [Figure 21] FIG. 21 is a side view of the aerial image display device according to the third embodiment. [Figure 22] FIG. 22 is a side view of an aerial image display device according to a fourth embodiment of the present invention. [Figure 23] FIG. 23 is a diagram illustrating the luminance of the lighting element according to the fifth embodiment of the present invention. [Figure 24] FIG. 24 is a side view of an aerial image display device according to a sixth embodiment of the present invention. [Figure 25A] FIG. 25A is a plan view of the light control element shown in FIG. [Figure 25B] FIG. 25B is a cross-sectional view of the light control element taken along the line AA′ in FIG. 25A. [Figure 26] FIG. 26 is a schematic diagram illustrating the effect of reducing moire in an aerial image. [Figure 27] FIG. 27 is a side view of an aerial image display device according to a seventh embodiment of the present invention. [Figure 28] FIG. 28 is a diagram illustrating the luminance of the display device. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, embodiments will be described with reference to the drawings. However, the drawings are schematic or conceptual, and the dimensions and proportions of each drawing are not necessarily the same as those of the actual drawing. Furthermore, even when the same parts are shown in different drawings, the dimensional relationships and proportions may be different. In particular, the following embodiments are illustrative of devices and methods for embodying the technical concept of the present invention, and the shape, structure, arrangement, etc. of the components do not specify the technical concept of the present invention. In the following description, elements having the same function and configuration are designated by the same reference numerals, and redundant description will be omitted.

[0024] [1] First embodiment [1-1] Configuration of aerial image display device 1 FIG. 1 is a perspective view of the main parts of an aerial image display device 1 according to a first embodiment of the present invention. In FIG. 1, the X direction is the direction along one side of the aerial image display device 1, the Y direction is the direction perpendicular to the X direction in a horizontal plane, and the Z direction is the direction perpendicular to the XY plane (also called the normal direction). FIG. 1 shows selected main components of the aerial image display device 1. FIG. 2 is a side view of the aerial image display device 1 according to the first embodiment. The side view of FIG. 2 is a side view on the XZ plane. The arrows in FIG. 2 schematically indicate the traveling direction of light.

[0025] The aerial image display device 1 is a device that displays images (including videos). The aerial image display device 1 displays an aerial image in the air above its own light emitting surface. "Displaying an aerial image" has the same meaning as "forming an aerial image." The light emitting surface of the aerial image display device 1 refers to the upper surface of the component that is arranged in the uppermost layer among the multiple components that make up the aerial image display device 1 and are arranged on the optical path. An aerial image is a real image that is formed in the air.

[0026] The aerial image display device 1 includes a display device 10, a light control element 40, an optical element 50, and a sensing element 60. The display device 10, the light control element 40, the optical element 50, and the sensing element 60 are arranged in this order along the Z direction and parallel to one another. The display device 10, the light control element 40, the optical element 50, and the sensing element 60 are fixed at specific positions by fixing members (not shown) so as to leave specific intervals between them. The display device 10, the light control element 40, the optical element 50, and the sensing element 60 are housed in a housing (not shown).

[0027] The display device 10 is configured as, for example, a liquid crystal display device. The display device 10 includes an illumination element (also called a backlight) 20 and a display panel 30. The illumination element 20 and the display panel 30 are arranged parallel to each other.

[0028] The illumination element 20 emits illumination light and outputs the illumination light toward the display panel 30. The illumination element 20 is, for example, a side light type illumination element. The illumination element 20 constitutes a surface light source. The detailed configuration of the illumination element 20 will be described later.

[0029] The display panel 30 is a transmissive display panel. The display panel 30 is configured with a liquid crystal display panel. There are no particular limitations on the drive mode of the display panel 30, and TN (Twisted Nematic) mode, VA (Vertical Alignment) mode, homogeneous mode, or the like can be used. The display panel 30 receives illumination light emitted from the lighting element 20. The display panel 30 transmits the illumination light from the lighting element 20 and performs optical modulation. The display panel 30 then displays a specific image on its screen.

[0030] The light control element 40 has a function of reducing unnecessary light. Unwanted light is a light component that does not contribute to generating an aerial image, and includes a light component that passes through the optical element 50 in the normal direction. The light control element 40 is configured to transmit a portion of the light from the display device 10 so that the light intensity is highest in an oblique direction at an angle θ1 with respect to the normal direction. That is, the light control element 40 is configured to transmit light components within a predetermined angular range centered on an oblique direction at an angle θ1 with respect to the normal direction, and to block light components outside this angular range. The light control element 40 is disposed so as to be spaced a distance d from the display device 10. The area of the light control element 40 is set to be equal to or larger than the area of the display device 10. The detailed configuration of the light control element 40 will be described later.

[0031] An anti-reflection layer 45 is provided on the bottom surface of the light control element 40. An anti-reflection layer 46 is provided on the top surface of the light control element 40. The anti-reflection layers 45, 46 are also called AR (Anti-Reflection) films. The anti-reflection layers 45, 46 act to suppress reflection of light incident thereon. The anti-reflection layers 45, 46 are configured, for example, by forming a transparent film having a refractive index different from that of the base film on a transparent base film. The anti-reflection layers 45, 46 act to reduce reflection of light by utilizing interference of light reflected by the two films. The anti-reflection layers 45, 46 may be configured by laminating three or more layers having different refractive indexes.

[0032] The optical element 50 reflects light incident from the bottom side toward the top side. The optical element 50 also reflects light incident obliquely from the bottom side toward, for example, the front direction (normal direction). The area of the optical element 50 is set to be equal to or greater than the area of the display device 10. The optical element 50 forms an aerial image 2 in the air. The aerial image 2 is parallel to the element surface of the optical element 50 and is a two-dimensional image. The element surface refers to a virtual plane on which the optical element 50 extends in the in-plane direction. The element surface has the same meaning as the in-plane. The same applies to the element surfaces of other elements. An observer standing in front of the optical element 50 can view the aerial image 2. The viewing direction of the aerial image 2 is the X direction. The viewing direction is the direction in which the observer can view the aerial image. That is, the observer views the aerial image 2 with both eyes parallel to the X direction. A detailed configuration of the optical element 50 will be described later.

[0033] The sensing element 60 is composed of a non-contact sensor (also called a hover sensor) that can detect an object without contact. The sensing element 60 forms a detection area in a two-dimensional spatial region that includes part or all of the aerial image 2 generated by the aerial image display device 1. The sensing element 60 detects an object (body) present in the detection area and detects the position of the object. The sensing element 60 is composed of, for example, a capacitance-type sensing element. The sensing element 60 is made of a transparent material. The area of the sensing element 60 is set to be equal to or larger than the area of the optical element 50. The sensing element 60 is also used as a cover member for the top surface of the aerial image display device 1. The sensing element 60 is not an essential requirement of the present invention and may be omitted.

[0034] [1-1-1] Configuration of lighting element 20 As shown in FIG. 2, the lighting element 20 includes a light source unit 21, a light guide plate 22, a reflective sheet 23, a diffusion sheet 24, and a prism sheet 25.

[0035] The light source unit 21 is arranged to face a side surface of the light guide plate 22. In this embodiment, the light source unit 21 is arranged on one side surface of the light guide plate 22 in the Y direction, and emits light toward the side surface of the light guide plate 22. The light source unit 21 may be arranged on the front side or the back side of the light guide plate 22 in the Y direction. In order to make the configuration easier to understand, FIG. 2 shows an example in which the light source unit 21 is arranged on the front side in the Y direction.

[0036] The light source unit 21 includes a plurality of light-emitting elements. The plurality of squares in the light source unit 21 in Fig. 2 are a simplified representation of the plurality of light-emitting elements. Each of the plurality of light-emitting elements is formed by a white LED (Light Emitting Diode). The plurality of light-emitting elements are arranged in a line in the X direction.

[0037] The light guide plate 22 guides the illumination light from the light source unit 21 and emits the illumination light from its upper surface.

[0038] The reflection sheet 23 is disposed on the bottom side of the light guide plate 22. The reflection sheet 23 reflects the illumination light emitted from the bottom surface of the light guide plate 22 back toward the light guide plate 22.

[0039] The diffusion sheet 24 is disposed on the upper surface side of the light guide plate 22. The diffusion sheet 24 diffuses the light from the light guide plate 22. The diffusion sheet 24 has a function of making the light emitted from the light guide plate 22 uniform within the plane.

[0040] The prism sheet 25 is disposed on the upper surface side of the diffusion sheet 24. The prism sheet 25 has a function of collecting light in the Y direction.

[0041] FIG. 3 is a perspective view of the prism sheet 25 included in the lighting element 20. The prism sheet 25 includes a plurality of prisms 25A, each extending in the X direction and aligned in the Y direction. Each of the plurality of prisms 25A is formed as a triangular prism. The prism sheet 25 in FIG. 3 functions to collect light in the Y direction. In other words, the prism sheet 25 functions to refract light along the Y direction. The prism sheet 25 in FIG. 3 does not have the function of collecting light in the X direction.

[0042] 1 indicates the extending direction of the prisms 25A. That is, the extending direction of the prisms 25A is the X direction.

[0043] [1-1-2] Configuration of the light control element 40 Fig. 4A is a plan view of the light control element 40 shown in Fig. 2. Fig. 4B is a cross-sectional view of the light control element 40 taken along line AA' in Fig. 4A. In the plane of Fig. 4A, a direction inclined at an angle θ2 with respect to the Y direction is referred to as an oblique direction D1.

[0044] The substrate 41 is configured to be flat in the XY plane and has a rectangular parallelepiped shape. The substrate 41 transmits light.

[0045] A plurality of transparent members 43 are provided on the substrate 41, each extending in the diagonal direction D1 and aligned in a direction perpendicular to the diagonal direction D1. A plurality of light-shielding members 44 are also provided on the substrate 41, each extending in the diagonal direction D1 and aligned in a direction perpendicular to the diagonal direction D1. The transparent members 43 and the light-shielding members 44 are alternately arranged so that adjacent members are in contact with each other. The diagonal direction D1 may be at an angle "-θ2" with respect to the Y direction. The three lines L2 shown in the light control element 40 in FIG. 1 indicate the extension directions of the transparent members 43 and the light-shielding members 44. The angle θ2 of the diagonal direction D1 with respect to the Y direction is called the bias angle of the light control element 40.

[0046] The base material 42 is provided on the plurality of transparent members 43 and the plurality of light blocking members 44. The base material 42 is configured to be planar in the XY plane and has a rectangular parallelepiped shape. The base material 42 transmits light.

[0047] The transparent member 43 extends in a diagonal direction at an angle θ1 with respect to the normal to the base material 41 in a cross-sectional shape viewed from the diagonal direction D1. The transparent member 43 has a parallelogram shape with its side surfaces tilted by the angle θ1 in a cross-sectional shape viewed from the diagonal direction D1. The transparent member 43 transmits light.

[0048] The light-shielding member 44 extends in a diagonal direction at an angle θ1 with respect to the normal direction of the base material 41 in a cross-sectional shape viewed from the diagonal direction D1. The light-shielding member 44 has a parallelogram shape with its side surfaces inclined by the angle θ1 in a cross-sectional shape viewed from the diagonal direction D1. The light-shielding member 44 blocks light. The thickness of the light-shielding member 44 is set to be thinner than the thickness of the transparent member 43.

[0049] Two adjacent light blocking members 44 are arranged so that their ends slightly overlap each other.

[0050] Glass or transparent resin (including acrylic resin) is used for the base materials 41 and 42 and the transparent member 43. For the light blocking member 44, for example, a resin mixed with black dye or pigment is used.

[0051] The light control element 40 may be configured without one or both of the base materials 41 and 42. The function of the light control element 40 can be realized if a plurality of transparent members 43 and a plurality of light blocking members 44 are arranged alternately.

[0052] The light control element 40 configured in this manner can transmit display light so that the light intensity in an oblique direction at an angle θ1 relative to the normal direction reaches a peak. The angle θ1 is set, for example, between 20 degrees and 40 degrees. The light control element 40 is configured to block light components outside the range of 30°±20° relative to the normal direction, for example.

[0053] [1-1-3] Configuration of optical element 50 Fig. 5 is a perspective view of the optical element 50 shown in Fig. 2. Fig. 5 also shows an enlarged view of a part of the optical element 50. The enlarged view in Fig. 5 is a side view in the XZ plane.

[0054] The optical device 50 includes a base material 51 and a plurality of optical elements 52. The base material 51 is configured to be planar in the XY plane and has a rectangular parallelepiped shape.

[0055] A plurality of optical elements 52 are provided on the bottom surface of the base material 51. Each of the plurality of optical elements 52 is formed as a triangular prism. The optical element 52 is arranged so that three side surfaces of the triangular prism are parallel to the XY plane, and one side surface is in contact with the base material 51. The plurality of optical elements 52 each extend in the Y direction and are arranged side by side in the X direction. In other words, the plurality of optical elements 52 have a sawtooth shape in the XZ plane. Three lines L1 shown in the optical element 50 in FIG. 1 indicate the extension directions of the optical elements 52.

[0056] Each of the optical elements 52 has an incident surface 53 and a reflecting surface 54. When viewed from the Y direction, the left side surface is the incident surface 53, and the right side surface is the reflecting surface 54. The incident surface 53 is a surface onto which light from the display device 10 is incident. The reflecting surface 54 is a surface that reflects light that has entered the incident surface 53 from the outside within the optical element 52. The incident surface 53 and the reflecting surface 54 are arranged at an angle θ p It has.

[0057] The substrate 51 and the optical elements 52 are made of a transparent material. The optical elements 52 are, for example, formed integrally with the substrate 51 using the same transparent material as the substrate 51. Alternatively, the substrate 51 and the optical elements 52 may be formed separately, and the optical elements 52 may be bonded to the substrate 51 using a transparent adhesive. The transparent material forming the substrate 51 and the optical elements 52 may be glass or a transparent resin (including an acrylic resin).

[0058] The optical element 50 thus configured internally reflects incident light to form a real image in the air. The optical element 50 also forms an aerial image 2 at a position in front of the element surface.

[0059] [1-2] Operation Next, the operation of the aerial image display device 1 configured as above will be described.

[0060] [1-2-1] Basic operation of the aerial image display device 1 First, the basic operation of the aerial image display device 1 will be described.

[0061] As shown in FIG. 2, illumination light emitted from the illumination element 20 passes through the display panel 30. Display light emitted from the display panel 30 is incident on the light control element 40. Of the light emitted from the display panel 30, a light component having an angle θ1 (including a light component within a predetermined angle range centered on the angle θ1) passes through the light control element 40. The light that has passed through the light control element 40 is incident on the optical element 50. The optical element 50 reflects the incident light in the direction opposite to the light control element 40, and forms an aerial image 2 in the air.

[0062] Fig. 6 is a perspective view illustrating how light is reflected by the optical element 50. Fig. 7 is a side view of the XZ plane illustrating how light is reflected by the optical element 50. Fig. 7 is a diagram illustrating the optical element 50 viewed from a state where both eyes of the observer 3 (i.e., the line connecting both eyes) are parallel to the X direction. Fig. 8 is a side view of the YZ plane illustrating how light is reflected by the optical element 50. Fig. 8 is a diagram illustrating the optical element 50 viewed from a state where both eyes of the observer 3 are parallel to the Y direction.

[0063] Light emitted from an arbitrary point "o" on the display device 10 is incident on the incident surface 53 of the optical element 50 and reaches the reflective surface 54. Light that reaches the reflective surface 54 at an angle greater than the critical angle relative to the normal to the reflective surface 54 is totally reflected by the reflective surface 54 and exits from the flat surface opposite the side of the optical element 50 on which the optical elements 52 are formed. The critical angle is the smallest incident angle above which total reflection occurs. The critical angle is the angle relative to the normal to the incident surface.

[0064] In the XZ plane of Figure 7, the light components emitted from point "o" that contribute to imaging are totally reflected by the reflecting surface 54 of the optical element 52, and the light is imaged in the air to generate an aerial image.

[0065] In the YZ plane of Figure 8, the light components emitted from point "o" that do not contribute to imaging are not reflected by the reflecting surface 54 of the optical element 52, and since that light does not form an image in the air, it does not contribute to the generation of an aerial image.

[0066] That is, the condition under which the observer 3 can view the aerial image is that both eyes of the observer 3 are parallel to the X direction or nearly so (for example, ±10 degrees with respect to the X direction). Furthermore, if the viewpoint of the observer 3 moves along the Y direction with both eyes parallel to the X direction or nearly so, the observer 3 can always recognize the aerial image.

[0067] FIG. 9 is a diagram illustrating the angular conditions of the incident surface 53 and the reflecting surface 54 of the optical element 50. As shown in FIG.

[0068] The angle of the incident surface 53 with respect to the Z direction (the direction perpendicular to the element surface) is θ3, the angle of the reflecting surface 54 with respect to the Z direction is θ4, and the angle between the incident surface 53 and the reflecting surface 54 is θ p Let the angle be θ p is expressed by the following equation (1). θ p =θ3+θ4 (1)

[0069] The light emitted from the light control element 40 at an angle θ1 is incident on the incident surface 53. If the refractive index of the material of the optical element 50 is n p The refractive index of air is 1. The angle of incidence at the incident surface 53 is θ5, and the angle of refraction is θ6. The angle of incidence at the reflecting surface 54 is θ7, and the angle of reflection is θ8 (=θ7). The angle of incidence at the top surface of the optical element 50 is θ9, and the angle of refraction is θ 10 The refraction angle θ 10 is the exit angle. Exit angle θ 10 is expressed by the following equation (2). θ 10 =sin -1 (n p *sin(sin -1 ((1 / n p )*sin(90°-(θ1+θ3)))+θ3+2θ4-90°)) ···(2)

[0070] The critical angle at the reflecting surface 54 is expressed by the following formula (3). Critical angle<θ7(=θ8) Critical angle=sin -1 (1 / n p ) ···(3)

[0071] That is, the incident angle θ7 on the reflecting surface 54 is set to be larger than the critical angle on the reflecting surface 54. In other words, the angle θ4 of the reflecting surface 54 is set so that the incident angle of light incident on the reflecting surface 54 is larger than the critical angle.

[0072] Furthermore, the angle θ3 of the incident surface 53 is set so that the light incident on the incident surface 53 is not totally reflected by the incident surface 53. In other words, the angle θ3 of the incident surface 53 is set so that the angle of incidence of the light incident on the incident surface 53 is smaller than the critical angle.

[0073] The angle between the element surface of the optical element 50 and the surface of the aerial image 2, and the distance between the element surface of the optical element 50 and the surface of the aerial image 2 can be adjusted by optimally setting the angle θ1 of light incident on the optical element 50, the refractive index of the optical element 50, the angle θ3 of the incident surface 53 of the optical element 50, and the angle θ4 of the reflecting surface 54 of the optical element 50.

[0074] [1-2-2] About Ghosts Next, the reduction of ghosts will be described. Ghosts are virtual images that are undesirable as aerial images. The aerial image 2 is a real image. Ghosts are visible around the aerial image 2.

[0075] First, the operation of the display device 10 will be described. Fig. 10 is a schematic plan view of the display device 10. Fig. 10 also shows a schematic view of the light source unit 21 and the display panel 30 included in the display device 10. In Fig. 10, the light source unit 21 is disposed on the far side in the Y direction relative to the light guide plate 22.

[0076] FIG. 11 is a diagram illustrating the luminance of the display device 10 along the line BX-BX' in FIG. 10. FIG. 12 is a diagram illustrating the luminance of the display device 10 along the line BY-BY' in FIG. 10. The horizontal axis of FIGS. 11 and 12 represents angle (degrees), and the vertical axis represents relative luminance (%). The angles in FIGS. 11 and 12 are angles at which an observer views the display device 10, and are the viewing angles (measurement angles) relative to the normal direction of the display device 10. An angle of 0 degrees corresponds to the case where the display device 10 is viewed from the normal direction. In other words, the luminance at an angle of 0 degrees is the front luminance of the display device.

[0077] 11 and 12 show four waveforms: "one prism sheet," "no prism sheet," comparative example 1, and comparative example 2. "One prism sheet" is the display device 10 of this embodiment, which is a display device including a prism sheet 25 whose prisms extend in the X direction. "No prism sheet" is a display device from which the prism sheet 25 has been removed. Comparative example 1 is a display device including two prism sheets whose prisms extend in orthogonal directions (specifically, a first prism sheet including prisms extending in the X direction and a second prism sheet including prisms extending in the Y direction). That is, comparative example 1 is a display device that uses a general backlight. Comparative example 2 is a display device including a single prism sheet whose prisms extend in the Y direction. In comparative example 2, the prism sheet focuses light in the X direction.

[0078] The light control element 40 transmits light so that the light intensity is greatest at an angle θ1. The angle θ1 of the light control element 40 is called the transmission angle of the light control element 40. In this embodiment, the angle θ1 is set to 30°.

[0079] 11, it can be seen that the display device 10 of this embodiment has the highest brightness at an angle of around 30 degrees. The brightness at angle θ1 in the display device 10 of this embodiment is set to 60% or more of its own front brightness. Furthermore, the brightness at angle θ1 in the display device 10 of this embodiment is set to 60% or more of the front brightness of the display device of Comparative Example 1.

[0080] Increasing the luminance at angle θ1 in display device 10 makes it possible to increase the luminance of light passing through light control element 40. This makes it possible to increase the luminance of aerial image 2 and reduce ghosting.

[0081] FIG. 13 is a diagram illustrating the luminance of light emitted from display device 10. Direction D2 shown in FIG. 13 is the front luminance direction of display device 10, and direction D3 is the luminance direction at a first angle (=θ1) of display device 10. The light component at angle θ1 of the light emitted from display device 10 is transmitted through light control element 40. The luminance at angle θ1 of the light emitted from display device 10 contributes to the formation of aerial image 2. The front luminance of the light emitted from display device 10 does not contribute to the formation of aerial image 2, and is a cause of ghosting.

[0082] In fact, the state of the aerial image was observed using the aerial image display device 1 of the embodiment and the aerial image display device of Comparative Example 1. It was confirmed that the ghost was reduced in this embodiment compared to Comparative Example 1.

[0083] Fig. 14 is a diagram illustrating the light emission characteristics of display device 10. The solid lines in Fig. 14 indicate light rays that optical element 50 uses to form aerial image 2. The dashed lines in Fig. 14 indicate light rays emitted from display device 10. The three dashed light rays in the figure can be realized by changing the transmission angle of light control element 40.

[0084] 14, the dashed light ray (the middle ray of the three) that overlaps with the solid light ray is the light component that forms the aerial image 2. In this embodiment, by increasing the luminance at angle θ1 in the display device 10, the luminance of the light used to form the aerial image 2 can be increased.

[0085] FIG. 15 is a diagram illustrating the luminance of the aerial image 2 formed by the aerial image display device 1. FIG. 15 shows the measurement results of an aerial image display device 1 (the embodiment shown in the figure) using a display device 10 with one prism sheet, and an aerial image display device (Comparative Example 1) using a display device of Comparative Example 1. FIG. 15 shows the luminance of the display device, the luminance of light transmitted through the light control element, the luminance of light transmitted through the optical element, and the luminance of the aerial image. From FIG. 15, it can be seen that the luminance of the aerial image in Comparative Example 1 was 183.1 (cd / m 2 ), and the luminance of the aerial image in this embodiment is 259.1 (cd / m 2) In this way, in this embodiment, the brightness of the aerial image 2 can be improved.

[0086] Furthermore, an anti-reflection layer 45 is provided on the bottom surface of the light control element 40, and an anti-reflection layer 46 is provided on the top surface of the light control element 40. This makes it possible to reduce reflected light between the display device 10 and the light control element 40. Furthermore, it is possible to reduce reflected light between the light control element 40 and the optical element 50. This makes it possible to prevent ghost images from appearing due to unnecessary reflected light between components. Note that the anti-reflection layers 45 and 46 are not essential requirements for the present invention, and may be omitted.

[0087] [1-2-3] Distance d between the display device 10 and the light control element 40 Next, a description will be given of the condition of the distance d between the display device 10 and the light control element 40. Fig. 16 is a diagram illustrating visual evaluation of the aerial image according to the distance d between the display device 10 and the light control element 40.

[0088] Aerial image display devices were fabricated with the distance d between the display device 10 and the light control element 40 set to 1 mm, 5 mm, 10 mm, and 15 mm, and the aerial images were visually evaluated for each. In the visual evaluation, it was confirmed whether ghosts were visible and whether tailing occurred in the aerial image. Trailing is a phenomenon in which the aerial image is displayed with a trailing effect. In Figure 16, items that met the evaluation criteria are marked with "○", and items that did not meet the evaluation criteria are marked with "×".

[0089] In this embodiment, the distance d is set to 0 to 15 mm. Preferably, the distance d is set to 5 to 10 mm. By setting the distance d to 5 to 10 mm, ghosting and trailing can be reduced. Therefore, a better aerial image can be displayed.

[0090] [1-2-4] Moiré in aerial images Next, we will explain how to reduce moire in an aerial image. Moire is a phenomenon in which stripes appear visually in an image, and is also called interference fringes.

[0091] Fig. 17 is a schematic diagram illustrating the effect of reducing moiré in an aerial image. Fig. 17 shows a display device 10, a light control element 40, and an optical element 50. Fig. 17 also shows a schematic planar arrangement of the display device 10, the light control element 40, and the optical element 50.

[0092] The display device 10 includes a plurality of pixels arranged in a matrix along the X and Y directions. The grid lines shown on the display device 10 in Fig. 17 schematically represent the plurality of pixels arranged in a matrix along the X and Y directions.

[0093] The plurality of transparent members 43 and the plurality of light-shielding members 44 of the light control element 40 extend in the oblique direction D1. As described above, the oblique direction D1 is inclined with respect to the Y direction. That is, the light control element 40 has a bias angle θ2.

[0094] The optical elements 52 of the optical device 50 extend in the Y direction.

[0095] Since the arrangement directions of the display device 10 and the light control element 40 are not aligned, it is possible to reduce the occurrence of moire in the aerial image due to the arrangement of the display device 10 and the light control element 40. Furthermore, since the arrangement directions of the light control element 40 and the optical element 50 are not aligned, it is possible to reduce the occurrence of moire in the aerial image due to the arrangement of the light control element 40 and the optical element 50.

[0096] The bias angle θ2 of the light control element 40 is set to be equal to or greater than 1 degree and equal to or less than 45 degrees. Preferably, the bias angle θ2 is set to be equal to or greater than 10 degrees and equal to or less than 30 degrees. In this embodiment, the bias angle θ2 is set to 20 degrees for evaluation.

[0097] If the bias angle θ2 is smaller than 10 degrees, the arrangement directions of the light control element 40 and the optical element 50 become aligned, which reduces the effect of reducing moire. Also, if the bias angle θ2 is smaller than 10 degrees, leakage of light in the front direction through the light control element 40 increases, making ghosts more visible.

[0098] If the bias angle θ2 is greater than 30 degrees, the arrangement directions of the light control element 40 and the display device 10 become aligned, reducing the effect of reducing moire. Also, if the bias angle θ2 is greater than 30 degrees, the amount of light leaking in the front direction through the light control element 40 increases, making ghosts more visible.

[0099] [1-3] Modified examples 18 is a side view of a modified aerial image display device 1. An anti-reflection layer 31 is provided on the upper surface of the display panel 30.

[0100] According to this modification, it is possible to further reduce the reflected light between the display device 10 and the light control element 40. This makes it possible to reduce ghosts caused by unnecessary reflected light between members.

[0101] [1-4] Effects of the first embodiment According to the first embodiment, the luminance at the angle θ1 in the display device 10 can be increased. Therefore, the luminance of light transmitted through the light control element 40 can be increased. This makes it possible to reduce ghosting, thereby improving the display quality of the aerial image 2. Furthermore, the front luminance of the aerial image 2 can be improved. This makes it possible to improve the display quality of the aerial image 2.

[0102] Furthermore, the distance d between the display device 10 and the light control element 40 is set to a predetermined distance, which reduces ghosting and tailing, thereby improving the display quality of the aerial image 2.

[0103] In addition, the light control element 40 is provided with a bias angle θ2, which makes it possible to reduce moire in the aerial image 2.

[0104] Additionally, anti-reflection layers 45 and 46 are provided on the top and bottom surfaces, respectively, of the light control element 40. Furthermore, an anti-reflection layer 31 is provided on the top surface of the display panel 30. This makes it possible to reduce ghosting.

[0105] The aerial image display device 1 can display an aerial image 2 in the air by reflecting light emitted from the display device 10 by the optical element 50. The aerial image display device 1 can also display the aerial image 2 in a direction parallel to the element surface of the optical element 50 in the front direction.

[0106] Furthermore, when the observer views the optical element 50 with both eyes parallel to or nearly parallel to the X direction (i.e., the direction in which the multiple optical elements 52 are arranged), the observer can view the aerial image 2. Furthermore, when the observer moves the viewpoint along the Y direction with both eyes parallel to or nearly parallel to the X direction, the observer can always view the aerial image 2. Furthermore, when the observer's eyes are parallel to or nearly parallel to the X direction, a wider viewing angle can be achieved.

[0107] Furthermore, it is possible to arrange multiple elements constituting the aerial image display device 1 in parallel, thereby realizing an aerial image display device 1 that can be made smaller in size in the Z direction.

[0108] Note that the embodiment optimizing the light-emitting characteristics of the display device 10 and the embodiment providing the bias angle θ2 to the light control element 40 may be implemented separately. That is, the present invention also includes an embodiment in which the light-emitting characteristics of the display device 10 are optimized while the light control element 40 is not provided with the bias angle θ2. This embodiment provides the effect of reducing ghosting. The present invention also includes an embodiment in which a general lighting element is used while the light control element 40 is provided with the bias angle θ2. This embodiment provides the effect of reducing moire in the aerial image.

[0109] [2] Second embodiment In the second embodiment, the display device 10 does not have a prism sheet.

[0110] FIG. 19 is a side view of the aerial image display device 1 according to the second embodiment of the present invention.

[0111] The lighting element 20 includes a light source unit 21, a light guide plate 22, a reflective sheet 23, and a diffusion sheet 24. The lighting element 20 does not include a prism sheet. The other configurations are the same as those in the first embodiment.

[0112] In this embodiment, the luminance distribution in the X direction of the display device 10 is the same as the waveform of "without prism sheet" in FIG.

[0113] It can be seen from FIG. 11 that the display device 10 without a prism sheet has higher brightness at an angle of around 30 degrees compared to the display device of Comparative Example 1. The brightness at angle θ1 of the display device 10 without a prism sheet is set to 60% or more of its own front brightness. Furthermore, the brightness at angle θ1 of the display device 10 without a prism sheet is set to 50% or more of the front brightness of the display device of Comparative Example 1. Therefore, ghosting can be reduced even in the display device 10 without a prism sheet.

[0114] 11, display device 10 without a prism sheet has low front luminance (luminance at an angle of 0 degrees). The front luminance of display device 10 is essentially unnecessary light for forming aerial image 2. Therefore, ghosting can be reduced from this perspective as well.

[0115] [3] Third embodiment In the third embodiment, the light source unit 21 is arranged on one side surface of the light guide plate 22 in the X direction.

[0116] Fig. 20 is a perspective view of the main part of an aerial image display device 1 according to a third embodiment of the present invention, and Fig. 21 is a side view of the aerial image display device 1 according to the third embodiment.

[0117] The lighting element 20 includes a light source unit 21 and a light guide plate 22. The light source unit 21 is disposed on one side surface of the light guide plate 22 in the X direction, and emits light toward the side surface of the light guide plate 22. The other configurations are the same as those in the first embodiment.

[0118] In this embodiment, the luminance distribution in the X direction of the display device 10 is the same as the waveform in Fig. 12. "One prism sheet" in Fig. 12 corresponds to the display device 10 of this embodiment.

[0119] The display device 10 is configured to have maximum brightness in an oblique direction (approximately 10 degrees in FIG. 12) relative to the front. This improves the light utilization efficiency of the light control element 40. This increases the brightness of light that passes through the light control element 40.

[0120] According to the third embodiment, the light emission direction of the light source unit 21 can be made the same as the viewing direction of the optical element 50. This can improve the front brightness of the aerial image 2. In addition, ghosting can be reduced.

[0121] [4] Fourth embodiment In the fourth embodiment, the light source unit 21 is disposed on one side surface of the light guide plate 22 in the X direction, and the display device 10 does not include a prism sheet.

[0122] FIG. 22 is a side view of the aerial image display device 1 according to the fourth embodiment of the present invention.

[0123] The lighting element 20 includes a light source unit 21, a light guide plate 22, a reflection sheet 23, and a diffusion sheet 24. The lighting element 20 does not include a prism sheet. The light source unit 21 is disposed on one side surface of the light guide plate 22 in the X direction, and emits light toward the side surface of the light guide plate 22.

[0124] In this embodiment, the luminance distribution in the X direction of the display device 10 is the same as the waveform in Fig. 12. "Without prism sheet" in Fig. 12 corresponds to the display device 10 of this embodiment.

[0125] 12, it can be seen that the display device 10 without a prism sheet has the highest brightness at an angle of about 30 degrees. That is, the display device 10 of this embodiment is configured to have the maximum brightness at an angle θ1.

[0126] According to the fourth embodiment, it is possible to improve the light utilization efficiency in the light control element 40. This makes it possible to increase the brightness of the light that passes through the light control element 40. In addition, it is possible to reduce ghosts.

[0127] [5] Fifth embodiment The fifth embodiment is another example of the prism sheet 25.

[0128] The prism sheet 25 of this embodiment is configured so that the prisms 25A face downward. That is, the prisms 25A of the prism sheet 25 face downward (toward the light guide plate 22). The prism sheet 25 of this embodiment is configured by turning the prism sheet of FIG. 3 upside down.

[0129] Fig. 23 is a diagram illustrating the luminance of the display device 10 according to the fifth embodiment of the present invention. Fig. 23 corresponds to the luminance of the display device 10 along the line BX-BX' in Fig. 10. The horizontal axis of Fig. 23 represents the angle (degrees), and the vertical axis represents the luminance (arbitrary unit).

[0130] 23, display device 10 has an extremely low front luminance. The front luminance of display device 10 is almost unnecessary light for forming aerial image 2. This improves the light utilization efficiency of display device 10. Furthermore, ghosting can be reduced.

[0131] Furthermore, the brightness at an angle of around 30 degrees (the brightness indicated by the dashed line in FIG. 23) is sufficiently high, so that the brightness of the aerial image 2 can be ensured sufficiently.

[0132] [6] Sixth embodiment In the sixth embodiment, a diffusion layer 70 is further provided between the display device 10 and the light control element 40.

[0133] 24 is a side view of an aerial image display device 1 according to a sixth embodiment of the present invention. The aerial image display device 1 further includes a diffusion layer 70. The diffusion layer 70 is disposed between the display device 10 and the light control element 40. The diffusion layer 70 has the function of diffusing light and making the light uniform within a plane.

[0134] Fig. 25A is a plan view of the light control element 40 shown in Fig. 24. Fig. 25B is a cross-sectional view of the light control element 40 taken along line AA' in Fig. 25A.

[0135] The light control element 40 includes base materials 41 and 42, a plurality of transparent members 43, and a plurality of light-shielding members 44. The plurality of transparent members 43 and the plurality of light-shielding members 44 each extend in the Y direction and are arranged side by side in the X direction. In other words, the bias angle of the light control element 40 is 0 degrees.

[0136] The transparent member 43 extends in an oblique direction at an angle θ1 with respect to the normal direction of the base material 41 on the XZ plane. The light blocking member 44 extends in an oblique direction at an angle θ1 with respect to the normal direction of the base material 41 on the XZ plane.

[0137] Fig. 26 is a schematic diagram illustrating the effect of reducing moiré in an aerial image. Fig. 26 shows a display device 10, a diffusion layer 70, a light control element 40, and an optical element 50. Fig. 26 also shows a schematic planar arrangement of the display device 10, the diffusion layer 70, the light control element 40, and the optical element 50.

[0138] The display device 10 includes a plurality of pixels arranged in a matrix along the X and Y directions. The grid lines shown on the display device 10 in Fig. 26 schematically represent the plurality of pixels arranged in a matrix along the X and Y directions.

[0139] The plurality of transparent members 43 and the plurality of light blocking members 44 of the light control element 40 extend in the Y direction. The plurality of optical elements 52 of the optical element 50 extend in the Y direction.

[0140] Moire may occur because the display device 10 and the light control element 40 are aligned in the same direction. The diffusion layer 70 diffuses the light from the display device 10. This reduces the occurrence of moire in the aerial image due to the alignment of the display device 10 and the light control element 40.

[0141] [7] Seventh embodiment In the seventh embodiment, an organic EL display device is used as the display device 10.

[0142] 27 is a side view of an aerial image display device 1 according to a seventh embodiment of the present invention. The aerial image display device 1 includes a display device 10, a light control element 40, an optical element 50, and a sensing element 60.

[0143] The display device 10 is a self-luminous display device, and is configured as an organic electroluminescence (EL) display device. In this embodiment, a backlight (illumination element) for the display device 10 is not required.

[0144] The configurations of the light control element 40, the optical element 50, and the sensing element 60 are the same as those in the first embodiment. The light control element 40 has a bias angle θ2. The transmission angle θ1 of the light control element 40 is set to 30 degrees.

[0145] FIG. 28 is a diagram illustrating the luminance of the display device 10. The waveform in FIG. 28 is the luminance on a line along the X direction that passes through the center of the display device 10. The horizontal axis of FIG. 28 represents the angle (degrees), and the vertical axis represents the relative luminance (%). The angle in FIG. 28 is the angle at which the observer views the display device 10. The luminance at an angle of 0 degrees is the front luminance of the display device 10. FIG. 28 shows an organic EL display device as an embodiment, and a general liquid crystal display device as a comparative example.

[0146] 28, the luminance at the angle θ1 in the display device 10 is set to 60% or more of its front luminance. By relatively increasing the luminance at the angle θ1 in the self-luminous display device 10, it is possible to increase the luminance of the light passing through the light control element 40. This makes it possible to reduce ghosting.

[0147] Other effects of the seventh embodiment are the same as those of the first embodiment. As a modification, an anti-reflection layer 31 may be provided on the upper surface of the display device 10. Furthermore, the sixth embodiment may be applied to the seventh embodiment.

[0148] [8] Variations In the above embodiment, the left side surface of optical element 52 is defined as incident surface 53, and the right side surface is defined as reflecting surface 54. However, this is not limitative, and incident surface 53 and reflecting surface 54 may be configured in reverse. In this case, the functions of aerial image display device 1 described in the embodiment are also reversed.

[0149] In the above embodiments, the terms film, layer, plate, etc. are used to describe examples of the components, and are not limited to the structures described by these names. A layer may be formed of a plate, etc., and conversely, a plate may be formed of a layer, etc. Furthermore, if a film can be formed on a component, the film may be formed as a layer.

[0150] In the above embodiment, expressions such as "orthogonal" and "perpendicular" may refer to a perfect 90-degree angle or may include an error angle from 90 degrees. Furthermore, expressions such as "parallel" may refer to a perfect parallel angle or may include an error angle.

[0151] The present invention is not limited to the above-described embodiments, and various modifications can be made in the implementation stage without departing from the spirit of the invention. Furthermore, the embodiments may be implemented in appropriate combinations, in which case the combined effects can be obtained. Furthermore, the above-described embodiments include various inventions, and various inventions can be extracted by combining selected elements from the disclosed elements. For example, if the problem can be solved and the desired effect can be obtained even if some elements are deleted from all elements shown in the embodiments, the configuration from which these elements are deleted can be extracted as an invention. [Explanation of symbols]

[0152] 1...aerial image display device, 2...aerial image, 3...observer, 10...display device, 20...illumination element, 21...light source unit, 22...light guide plate, 23...reflective sheet, 24...diffusion sheet, 25...prism sheet, 30...display panel, 31...anti-reflection layer, 40...light control element, 41, 42...substrate, 43...transparent member, 44...light-shielding member, 45, 46...anti-reflection layer, 50...optical element, 51...substrate, 52...optical element, 53...incident surface, 54...reflective surface, 60...sensing element, 70...diffusion layer

Claims

1. a display device for displaying an image; a light control element disposed to receive light from the display device and transmitting a portion of the light from the display device; an optical element that is arranged to receive light from the light control element, reflects the light from the light control element to an opposite side to the display device, and forms an aerial image in the air; Equipped with the light control element includes a plurality of transparent members and a plurality of light blocking members arranged alternately; the plurality of transparent members and the plurality of light blocking members are inclined at a first angle with respect to a normal to the display device; The optical element includes a planar substrate and a plurality of optical elements provided below the substrate, each extending in a first direction and aligned in a second direction perpendicular to the first direction; each of the plurality of optical elements has an incident surface and a reflecting surface that are inclined with respect to a normal direction of the base material and are in contact with each other; the entrance surface is positioned to receive light from the display device; an angle of the incident surface with respect to a normal direction of the substrate is set so that an incident angle of light from the light control element is smaller than a critical angle; an angle of the reflecting surface with respect to a normal direction of the base material is set so that an incident angle of light from the incident surface is larger than a critical angle; The luminance of the display device at the first angle is 60% or more of the luminance at the front of the display device. Aerial image display device.

2. a display device for displaying an image; a light control element disposed to receive light from the display device and transmitting a portion of the light from the display device; an optical element that is arranged to receive light from the light control element, reflects the light from the light control element to an opposite side to the display device, and forms an aerial image in the air; Equipped with the light control element includes a plurality of transparent members and a plurality of light blocking members arranged alternately; the plurality of transparent members and the plurality of light blocking members are inclined at a first angle with respect to a normal to the display device; The optical element includes a planar substrate and a plurality of optical elements provided below the substrate, each extending in a first direction and aligned in a second direction perpendicular to the first direction; each of the plurality of optical elements has an incident surface and a reflecting surface that are inclined with respect to a normal direction of the base material and are in contact with each other; the entrance surface is positioned to receive light from the display device; an angle of the incident surface with respect to a normal direction of the substrate is set so that an incident angle of light from the light control element is smaller than a critical angle; an angle of the reflecting surface with respect to a normal direction of the base material is set so that an incident angle of light from the incident surface is larger than a critical angle; A third direction in which the transparent members and the light blocking member extend is set obliquely with respect to the first direction. Aerial image display device.

3. The display device includes an illumination element that emits light, and a display panel that is disposed to receive the light from the illumination element and displays the image.

3. The aerial image display device according to claim 1 or 2.

4. the lighting element includes only one prism sheet that condenses light; The prism sheet includes a plurality of prisms each extending in the second direction.

4. The aerial image display device according to claim 3.

5. The plurality of prisms are arranged to face upward.

5. The aerial image display device according to claim 4.

6. The plurality of prisms are arranged to face downward.

5. The aerial image display device according to claim 4.

7. The lighting element does not have a prism sheet.

4. The aerial image display device according to claim 3.

8. the lighting element includes a light source unit and a light guide plate; The light source unit is disposed on one side surface of the light guide plate in the second direction.

4. The aerial image display device according to claim 3.

9. The display device is a self-luminous display device including an organic EL.

3. The aerial image display device according to claim 1 or 2.

10. The display device further includes a diffusion layer disposed between the display device and the light control element, for diffusing light.

3. The aerial image display device according to claim 1 or 2.

11. The display device and the light control element are disposed at a distance from each other.

3. The aerial image display device according to claim 1 or 2.

12. The optical control element further includes an anti-reflection layer provided on the optical element side.

3. The aerial image display device according to claim 1 or 2.

13. The light control element further includes an anti-reflection layer provided on the display device side.

3. The aerial image display device according to claim 1 or 2.

14. The display device further includes an anti-reflection layer provided on the light control element side.

3. The aerial image display device according to claim 1 or 2.

15. The optical element is configured to form the aerial image parallel to the display device.

3. The aerial image display device according to claim 1 or 2.

Images