Airborne display device

Abstract

To provide an aerial display device which has an increasable display quality.SOLUTION: The aerial display device includes: a display element 20 for displaying an image; an optical element 50 arranged to receive light from the display element 20, the optical element reflecting light from the display element 20 to the opposite side to the side where the display element 20 is located and forming an aerial image in the sky; and a housing 60 surrounding the optical element 50 to fix the optical element 50. An element is arranged to face the optical element 50 and is larger than the optical element 50.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Aerial display devices capable of displaying images and videos as aerial images are being researched and are expected to be a new human-machine interface. For example, an aerial display device may include a two-sided corner reflector array in which two-sided corner reflectors are arranged in an array, reflecting light emitted from the display surface of a display element and forming a real image in the air. The display method using a two-sided corner reflector array is aberration-free and can display a real image (aerial image) in a plane-symmetrical position.

[0003] Patent Document 1 discloses an optical element in which a transparent rectangular prism protruding from the surface of a transparent flat plate is used as a two-sided corner reflector, and multiple rectangular prisms are arranged in an array on a plane. Patent Document 2 discloses an optical element in which each of the first and second light control panels is formed by arranging multiple planar light reflecting parts perpendicularly inside a transparent flat plate, and the first and second light control panels are arranged so that their planar light reflecting parts are orthogonal to each other. The optical elements of Patent Documents 1 and 2 generate an aerial image by reflecting light emitted from a display element twice on orthogonal reflective surfaces.

[0004] The display devices using optical elements described in Patent Documents 1 and 2 can recognize an aerial image by observing the optical element from an oblique direction, but it is difficult to recognize a good aerial image by observing it from the direction normal to the optical element. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2011-191404 [Patent Document 2] Japanese Patent Publication No. 2011-175297 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The present invention provides an aerial display device capable of improving display quality. [Means for solving the problem]

[0007] According to a first aspect of the present invention, an aerial display device is provided, comprising: a display element for displaying an image; an optical element arranged to receive light from the display element and reflecting the light from the display element to the opposite side of the display element to form an aerial image in the air; and a housing configured to surround the optical element and fix the optical element, wherein the area of ​​an element arranged opposite the optical element is larger than the area of ​​the optical element.

[0008] According to a second aspect of the present invention, an aerial display device according to the first aspect is provided, further comprising an orientation control element disposed between the display element and the optical element, which transmits the oblique light component of the light from the display element, wherein the area of ​​the orientation control element is larger than the area of ​​the optical element.

[0009] According to a third aspect of the present invention, an aerial display device according to the second aspect is provided, wherein the outer circumference of the orientation control element extends to the housing.

[0010] According to a fourth aspect of the present invention, an aerial display device according to the second aspect is provided, further comprising a light-absorbing layer provided on the bottom surface of the orientation control element, having an opening through which light from the display element passes, and absorbing light.

[0011] According to a fifth aspect of the present invention, an aerial display device according to the fourth aspect is provided, wherein the outer periphery of the light-absorbing layer extends to the outer periphery of the orientation control element.

[0012] According to a sixth aspect of the present invention, an aerial display device according to a second aspect is provided, wherein the orientation control element includes a plurality of alternately arranged transparent members and a plurality of light-shielding members, and the plurality of light-shielding members are inclined with respect to the normal direction of the orientation control element.

[0013] According to a seventh aspect of the present invention, there is provided an aerial display device according to the second aspect, further comprising an antireflection layer provided on an upper surface of the orientation control element.

[0014] According to an eighth aspect of the present invention, there is provided an aerial display device according to the first aspect, further comprising a transparent support member disposed between the display element and the optical element, wherein an area of the support member is larger than an area of the optical element.

[0015] According to a ninth aspect of the present invention, there is provided an aerial display device according to the eighth aspect, wherein an outer periphery of the support member extends to the housing.

[0016] According to a tenth aspect of the present invention, there is provided an aerial display device according to the eighth aspect, further comprising a light absorption layer provided on a bottom surface of the support member, having an opening that allows light from the display element to pass through, and absorbing light.

[0017] According to an eleventh aspect of the present invention, there is provided an aerial display device according to the tenth aspect, wherein an outer periphery of the light absorption layer extends to an outer periphery of the support member.

[0018] According to a twelfth aspect of the present invention, there is provided an aerial display device according to the eighth aspect, further comprising an antireflection layer provided on an upper surface of the support member.

[0019] According to a thirteenth aspect of the present invention, there is provided an aerial display device according to the first aspect, wherein the optical element includes a planar base material and a plurality of optical elements provided below the base material, each extending in a first direction and arranged side by side in a second direction orthogonal to the first direction, and each of the plurality of optical elements is inclined with respect to a normal direction of the base material and has an incident surface and a reflecting surface that are in contact with each other.

[0020] According to a fourteenth aspect of the present invention, there is provided an aerial display device according to the first aspect, wherein the display element and the optical element are arranged parallel to each other. Effects of the Invention

[0021] According to the present invention, an aerial display device capable of improving display quality can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] [Figure 1] FIG. 1 is an exploded view of an aerial display device according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a plan view of the aerial display device shown in FIG. 1. [Figure 3] FIG. 3 is a cross-sectional view of the aerial display device taken along line A-A' in FIG. 2. [Figure 4] FIG. 4 is a schematic side view for explaining an optical path of the aerial display device. [Figure 5A] FIG. 5A is a plan view of the alignment control element shown in FIG. 1. [Figure 5B] FIG. 5B is a cross-sectional view of the alignment control element taken along line B-B' in FIG. 5A. [Figure 6] FIG. 6 is a schematic cross-sectional view for explaining the area of the alignment control element. [Figure 7] FIG. 7 is a perspective view of the optical element shown in FIG. 1. [Figure 8] FIG. 8 is a block diagram of the aerial display device. [Figure 9] FIG. 9 is a perspective view for explaining how light is reflected by the optical element. [Figure 10] FIG. 10 is a side view on the XZ plane for explaining how light is reflected by the optical element. [Figure 11] FIG. 11 is a side view on the YZ plane for explaining how light is reflected by the optical element. [Figure 12] FIG. 12 is a diagram for explaining the angular conditions of the incident surface and the reflecting surface in the optical element. [Figure 13] FIG. 13 is a diagram for explaining the state of external light incident on the aerial display device. [Figure 14] FIG. 14 is a cross-sectional view of an aerial display device according to a modified example. [Figure 15]Figure 15 is an exploded view of an aerial display device according to a comparative example. [Figure 16] Figure 16 is a partial cross-sectional view along the X direction of an aerial display device according to a comparative example. [Figure 17] Figure 17 illustrates the behavior of ambient light entering an aerial display device. [Figure 18] Figure 18 is a diagram illustrating the display element image and the optical element image. [Figure 19] Figure 19 is a cross-sectional view along the X direction of an aerial display device according to a second embodiment of the present invention. [Figure 20] Figure 20 illustrates how light is reflected inside an aerial display device. [Figure 21] Figure 21 is an exploded view of an aerial display device according to a third embodiment of the present invention. [Figure 22] Figure 22 is a cross-sectional view of the aerial display device shown in Figure 21, along the X direction. [Figure 23] Figure 23 illustrates how ambient light enters an aerial display device. [Figure 24] Figure 24 is a cross-sectional view of an aerial display device according to a modified example. [Modes for carrying out the invention]

[0023] The embodiments will be described below with reference to the drawings. However, the drawings are schematic or conceptual, and the dimensions and proportions in each drawing are not necessarily the same as those in reality. Furthermore, even when the same part is represented between drawings, the relationship between dimensions and proportions may be represented differently. In particular, the embodiments shown below are illustrative examples of devices and methods for realizing the technical concept of the present invention, and the technical concept of the present invention is not determined by the shape, structure, arrangement, etc. of the components. In the following description, elements having the same function and configuration are denoted by the same reference numerals, and redundant descriptions are omitted.

[0024] [1] First Embodiment [1-1] Configuration of the aerial display device 1 Figure 1 is an exploded view of an aerial display device 1 according to the first embodiment of the present invention. In Figure 1, the X direction is the direction along one side of the aerial display device 1, the Y direction is the direction perpendicular to the X direction in the horizontal plane, and the Z direction is the direction perpendicular to the XY plane (also called the normal direction). Figure 2 is a plan view of the aerial display device 1 shown in Figure 1. Figure 3 is a cross-sectional view of the aerial display device 1 along line AA' in Figure 2. Figure 4 is a schematic side view illustrating the optical path of the aerial display device 1.

[0025] The aerial display device 1 is a device that displays images (including videos). The aerial display device 1 displays an aerial image in the air above its own light-emitting surface. The light-emitting surface of the aerial display device 1 refers to the upper surface of the uppermost component among the multiple components that make up the aerial display device 1. An aerial image is a real image formed in the air.

[0026] The aerial display device 1 comprises an illumination element (also called a backlight) 10, a display element 20, a light-absorbing layer 30, an alignment control element 40, an optical element 50, and a housing 60. The illumination element 10, the display element 20, the light-absorbing layer 30, the alignment control element 40, and the optical element 50 are arranged in this order along the Z direction and are arranged parallel to each other. The illumination element 10, the display element 20, and the alignment control element 40 are fixed in desired positions by fixing members (not shown) so as to maintain a desired distance from each other.

[0027] The illumination element 10 emits illumination light and directs this illumination light toward the display element 20. The illumination element 10 comprises a light source unit 11, a light guide plate 12, and a reflective sheet 13. The illumination element 10 is, for example, a side-light type illumination element. The illumination element 10 constitutes a surface light source. The illumination element 10 may be configured so that the light intensity peaks in an oblique direction at an angle θ1, as described later.

[0028] The light source unit 11 is positioned to face the side of the light guide plate 12. The light source unit 11 emits light toward the side of the light guide plate 12. The light source unit 11 includes a plurality of light-emitting elements, such as white LEDs (Light Emitting Diodes). The light guide plate 12 guides the illumination light from the light source unit 11 and emits the illumination light from its upper surface. The reflective sheet 13 reflects the illumination light emitted from the bottom surface of the light guide plate 12 back toward the light guide plate 12. The illumination element 10 may have members (including a prism sheet and a diffusion sheet) on the upper surface of the light guide plate 12 to improve optical properties.

[0029] The display element 20 is a transmissive display element. The display element 20 is composed of, for example, a liquid crystal display element. The driving mode of the display element 20 is not particularly limited, and TN (Twisted Nematic) mode, VA (Vertical Alignment) mode, or homogeneous mode can be used. The display element 20 receives illumination light emitted from the illumination element 10. The display element 20 transmits the illumination light from the illumination element 10 and performs light modulation. Then, the display element 20 displays a desired image on its display surface.

[0030] The light-absorbing layer 30 has the function of absorbing light and blocking light. The light-absorbing layer 30 has a rectangular opening 31. The opening 31 has an area approximately the same as the display surface of the display element 20 and exposes the display surface of the display element 20. The outer periphery of the light-absorbing layer 30 extends to the outer periphery of the orientation control element 40. The light-absorbing layer 30 is made of a resin mixed with, for example, black dye or pigment. The light-absorbing layer 30 is formed in a film shape and bonded to the bottom surface of the orientation control element 40 using a transparent adhesive. The light-absorbing layer 30 is bonded to the outer periphery of the display element 20 using a transparent adhesive. The light-absorbing layer 30 may also be made of black paint and formed by applying this black paint to the bottom surface of the orientation control element 40.

[0031] The orientation control element 40 has the function of reducing unwanted light. Unwanted light is light components that do not contribute to the generation of an aerial image and includes light components that are transmitted through the optical element 50 in the normal direction. The orientation 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, while blocking light components outside of the above angular range. The detailed configuration of the orientation control element 40 will be described later.

[0032] The area of ​​the orientation control element 40 is larger than the area of ​​the display element 20. The length of the orientation control element 40 in the X direction is longer than the length of the display element 20 in the X direction. In Figure 3, the right end of the orientation control element 40 is located to the right of the right end of the display element 20, and the left end of the orientation control element 40 is located to the left of the left end of the display element 20. The length of the orientation control element 40 in the Y direction is longer than the length of the display element 20 in the Y direction.

[0033] The optical element 50 reflects light incident from the bottom side to the top side. It also reflects incident light that enters obliquely from the bottom side, for example, in the forward direction (normal direction). The detailed configuration of the optical element 50 will be described later.

[0034] The area of ​​the optical element 50 is larger than the area of ​​the display element 20 and smaller than the area of ​​the alignment control element 40. The length of the optical element 50 in the X direction is longer than the length of the display element 20 in the X direction and shorter than the length of the alignment control element 40 in the X direction. In Figure 3, the right end of the optical element 50 is located between the right end of the display element 20 and the right end of the alignment control element 40, and the left end of the optical element 50 is located between the left end of the display element 20 and the left end of the alignment control element 40. The length of the optical element 50 in the Y direction is longer than the length of the display element 20 in the Y direction and shorter than the length of the alignment control element 40 in the Y direction.

[0035] The optical element 50 forms an aerial image 2 in the air. The aerial image 2 is parallel to the element plane of the optical element 50 and is a two-dimensional image. The element plane refers to a virtual plane that extends in the in-plane direction of the optical element 50. The element plane has the same meaning as in-plane. The same meaning applies to the element planes of other elements. An observer 3 standing in front of the optical element 50 can see the aerial image 2.

[0036] The housing 60 has a rectangular frame shape and is equipped with four side panels. The side panels of the housing 60 have an inverted L-shaped cross-section. A rectangular opening 61 is provided at the top of the housing 60, and a step is provided around the opening 61. The optical element 50 is placed on the step at the top of the housing 60 and fitted into the opening 61. The housing 60 and the optical element 50 are bonded together with a transparent adhesive.

[0037] The area of ​​the opening at the bottom of the housing 60 is set to be the same as the area of ​​the orientation control element 40. The orientation control element 40 is fitted into the opening at the bottom of the housing 60. The housing 60 and the orientation control element 40 are bonded together with a transparent adhesive.

[0038] The housing 60 is preferably made of a material capable of reducing light reflection. For example, the housing 60 is made of black resin. For example, the inner surface of the housing 60 is roughened. A roughened surface can reduce light reflection.

[0039] Furthermore, any configuration can be used for the bottom of the housing 60. The housing 60 may be configured as a box shape capable of housing the illumination element 10, display element 20, light absorption layer 30, orientation control element 40, and optical element 50, that is, it may be configured as a box having a bottom plate positioned below the illumination element 10.

[0040] [1-1-1] Configuration of the orientation control element 40 Figure 5A is a plan view of the orientation control element 40 shown in Figure 1. Figure 5B is a cross-sectional view of the orientation control element 40 along the line BB' in Figure 5A.

[0041] The substrate 41 is planar in the XY plane and has a rectangular parallelepiped. The substrate 41 transmits light.

[0042] Multiple transparent members 43 are provided on the base material 41, each extending in the Y direction and aligned in the X direction. Additionally, multiple light-shielding members 44 are provided on the base material 41, each extending in the Y direction and aligned in the X direction. The multiple transparent members 43 and the multiple light-shielding members 44 are arranged alternately so that adjacent members are in contact with each other.

[0043] Multiple transparent members 43 and multiple light-shielding members 44 are provided on a base material 42. The base material 42 is planar in the XY plane and has a rectangular parallelepiped shape. The base material 42 transmits light.

[0044] The transparent member 43 extends in an oblique direction at an angle θ1 with respect to the normal direction of the base material 41 in the XZ plane. The transparent member 43 is a parallelogram with its side surface inclined by an angle θ1 in the XZ plane. The transparent member 43 transmits light.

[0045] The light-shielding member 44 extends in an oblique direction at an angle θ1 with respect to the normal direction of the base material 41 in the XZ plane. The light-shielding member 44 is a parallelogram with its side surface inclined by an angle θ1 in the XZ plane. 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.

[0046] The two adjacent light-shielding members 44 are arranged so that their ends slightly overlap in the Z direction.

[0047] The base materials 41, 42 and the transparent member 43 are made of glass or a transparent resin (including acrylic resin). The light-shielding member 44 is made of, for example, a resin mixed with black dye or pigment.

[0048] The orientation control element 40 may be constructed by omitting one or both of the base materials 41 and 42. The function of the orientation control element 40 can be realized if a plurality of transparent members 43 and a plurality of light-shielding members 44 are arranged alternately.

[0049] The orientation control element 40 configured in this way can transmit display light such that the light intensity in the oblique direction at an angle θ1 with respect to the normal direction is at its peak. For example, the orientation control element 40 is configured to block light components outside the range of 30°±30° with respect to the normal direction. Preferably, the orientation control element 40 is configured to block light components outside the range of 30°±20° with respect to the normal direction.

[0050] Figure 6 is a schematic cross-sectional view illustrating the area of ​​the orientation control element 40. In this embodiment, the orientation control element 40, which is the element facing the optical element 50, is set to have a length in the X direction that is longer than the length of the optical element 50 in the X direction.

[0051] In Figure 6, point "o'" represents an arbitrary position of light emitted from the orientation control element 40. Point "o''" in Figure 6 represents the position where light emitted from the optical element 50 forms an image, and where the aerial image 2 is formed. The arrows extending from point "o'" represent the principal rays. The principal rays are rays that pass through the center of the radially spreading light components.

[0052] The length I of the orientation control element 40 in the X direction is expressed by the following equation (1). I ≤ x + 2x' = x + 2y' tanθ e ...(1) x'=y'*tanθ e x: Length of the opening 61 of the housing 60 in the X direction y: Distance from optical element 50 to aerial image 2 x': Distance from the optical element 50 to the end of the housing 60 in the X direction y': Distance from optical element 50 to alignment control element 40 θ e : Principal ray emission angle (angle between the perpendicular line of the orientation control element 40 and the principal ray)

[0053] The length x of the aperture 61 in the X direction is a design value designed based on the specifications required for the aerial display device 1. The distance y from the optical element 50 to the aerial image 2 is a design value designed based on the specifications required for the aerial display device 1. The distance y' from the optical element 50 to the orientation control element 40 is a design value optimally designed based on distance y.

[0054] The longer the length I of the orientation control element 40 in the X direction, the larger the size of the housing 60 becomes. Therefore, from the perspective of reducing the size of the housing 60, "I = x + 2 * x'" is the most desirable.

[0055] Furthermore, the orientation control element 40 is set to have a length in the Y direction that is longer than the length of the optical element 50 in the Y direction.

[0056] [1-1-2] Configuration of the optical element 50 Figure 7 is a perspective view of the optical element 50 shown in Figure 1. Figure 7 also shows an enlarged view of a part of the optical element 50. The enlarged view in Figure 7 is a side view in the XZ plane.

[0057] The optical element 50 comprises a substrate 51 and a plurality of optical elements 52. The substrate 51 is planar in the XY plane and has a rectangular parallelepiped.

[0058] Multiple optical elements 52 are provided on the bottom surface of the base material 51. Each of the multiple optical elements 52 is composed of a triangular prism. The optical elements 52 are arranged such that three sides of the triangular prism are parallel to the XY plane, and one side is in contact with the base material 51. Each of the multiple optical elements 52 extends in the Y direction and is arranged in a line in the X direction. In other words, the multiple optical elements 52 have a sawtooth shape in the XZ plane.

[0059] Each of the multiple optical elements 52 has an incident surface 53 and a reflecting surface 54. When viewed from the Y direction, the left side is the incident surface 53 and the right side is the reflecting surface 54. The incident surface 53 is the surface to which light from the display element 20 is incident. The reflecting surface 54 is the surface that reflects the light incident on the incident surface 53 from the outside within the optical element 52. The angle between the incident surface 53 and the reflecting surface 54 is θ p It holds.

[0060] The base material 51 and the optical element 52 are made of a transparent material. The optical element 52 is formed integrally with the base material 51, for example, using the same transparent material as the base material 51. Alternatively, the base material 51 and the optical element 52 may be formed separately, and the optical element 52 may be bonded to the base material 51 using a transparent adhesive. Glass or a transparent resin (including acrylic resin) can be used as the transparent material constituting the base material 51 and the optical element 52.

[0061] The optical element 50 configured in this way reflects incident light internally to form a real image in the air. The optical element 50 also forms an aerial image at a position directly in front of the element surface.

[0062] [1-1-3] Block configuration of the aerial display device 1 Figure 8 is a block diagram of the aerial display device 1. The aerial display device 1 comprises a control unit 70, a storage unit 71, an input / output interface (input / output IF) 72, a display unit 73, and an input unit 74. The control unit 70, the storage unit 71, and the input / output interface 72 are connected to each other via a bus 75.

[0063] The input / output interface 72 is connected to the display unit 73 and the input unit 74. The input / output interface 72 performs interface processing for each of the display unit 73 and the input unit 74 according to a predetermined standard.

[0064] The display unit 73 includes an illumination element 10 and a display element 20. The display unit 73 displays an image.

[0065] The control unit 70 is composed of one or more processors, such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The control unit 70 implements various functions by executing programs stored in the memory unit 71. The control unit 70 includes a display processing unit 70A and an information processing unit 70B.

[0066] The display processing unit 70A controls the operation of the display unit 73 (specifically, the illumination element 10 and the display element 20). The display processing unit 70A controls the on and off of the illumination element 10. The display processing unit 70A transmits an image signal to the display element 20 and causes the display element 20 to display an image.

[0067] The information processing unit 70B generates the image to be displayed by the aerial display device 1. The information processing unit 70B can use image data stored in the storage unit 71. The information processing unit 70B may also acquire image data from an external source using a communication function (not shown).

[0068] The storage unit 71 includes non-volatile storage devices such as ROM (Read Only Memory), HDD (Hard Disk Drive), and SSD (Solid State Drive), and volatile storage devices such as RAM (Random Access Memory) and registers. The storage unit 71 stores the program executed by the control unit 70. The storage unit 71 stores various data necessary for controlling the control unit 70. Furthermore, the storage unit 71 stores the image data displayed by the aerial display device 1.

[0069] The input unit 74 includes, for example, a touch panel or buttons, and receives information entered by the user. The information processing unit 70B can select an image to display on the display unit 73 based on the information received by the input unit 74.

[0070] [1-2] Operation of the aerial display device 1 Next, the operation of the aerial display device 1 configured as described above will be explained.

[0071] [1-2-1] Display operation The arrows in Figure 4 indicate the optical path. As shown in Figure 4, light emitted from any point "o" on the display element 20 enters the orientation control element 40. Of the light emitted from the display element 20, the optical component at angle θ1 (including the optical component within a predetermined angular range centered on angle θ1) passes through the orientation control element 40. The light that has passed through the orientation control element 40 enters the optical element 50. The optical element 50 images the incident light into the air on the opposite side of the orientation control element 40, displaying an aerial image 2 in the air.

[0072] Figure 9 is a perspective view illustrating the reflection of light in the optical element 50. Figure 10 is a side view of the XZ plane illustrating the reflection of light in the optical element 50. Figure 10 shows the optical element 50 as seen by observer 3 with both eyes (i.e., the line connecting both eyes) parallel to the X direction. Figure 11 is a side view of the YZ plane illustrating the reflection of light in the optical element 50. Figure 11 shows the optical element 50 as seen by observer 3 with both eyes parallel to the Y direction.

[0073] Light emitted from any point "o'" of the orientation control element 40 enters the incident surface 53 of the optical element 50 and reaches the reflection surface 54. Light that reaches the reflection surface 54 at an angle greater than the critical angle with respect to the normal direction of the reflection surface 54 is totally reflected by the reflection surface 54 and is emitted from the plane opposite to the side of the optical element 52 of the optical element 50. The critical angle is the smallest angle of incidence beyond which total reflection occurs. The critical angle is the angle with respect to the perpendicular to the incident surface.

[0074] In the XZ plane of Figure 10, light emitted from point "o'" is totally reflected by the reflective surface 54 of the optical element 52, and the light is imaged in the air to generate an aerial image.

[0075] In the YZ plane of Figure 11, the light emitted from point "o'" is not reflected by the reflective surface 54 of the optical element 52, and therefore does not form an image in the air, thus not contributing to the generation of an aerial image.

[0076] That is, the condition for the observer 3 to recognize the aerial image is that both eyes of the observer 3 are parallel to the X direction or close to this state (for example, ±10 degrees with respect to the X direction). In addition, when both eyes of the observer 3 are parallel to the X direction or close to this state and the viewpoint is moved along the Y direction, the aerial image can always be recognized.

[0077] FIG. 12 is a diagram for explaining the angular conditions of the incident surface 53 and the reflection surface 54 in the optical element 50.

[0078] let θ2 be the angle of the incident surface 53 with respect to the Z direction (the direction perpendicular to the element surface), θ3 be the angle of the reflection surface 54 with respect to the Z direction, and θ be the angle formed between the incident surface 53 and the reflection surface 54 p . angle θ p is represented by the following formula (2). θ p =θ2+θ3···(2)

[0079] Light emitted from the orientation control element 40 at an angle θ1 is incident on the incident surface 53. Let n p be the refractive index of the material of the optical element 50, and the refractive index of air is 1. Let θ4 be the incident angle on the incident surface 53, and θ5 be the refraction angle. Let θ6 be the incident angle on the reflection surface 54, and θ7 (=θ6) be the reflection angle. Let θ8 be the incident angle on the upper surface of the optical element 50, and θ9 be the refraction angle. The refraction angle θ9 is the emission angle. The emission angle θ9 is represented by the following formula (3). θ9=sin -1 (n p *sin(sin -1 ((1 / n p )*sin(90°-(θ1+θ2)))+θ2+2θ3-90°)) ···(3)

[0080] The critical angle at the reflection surface 54 is represented by the following formula (4). Critical angle < θ6(=θ7) Critical angle=sin -1 (1 / n p ) ···(4)

[0081] In other words, the angle of incidence θ6 at the reflective surface 54 is set to be greater than the critical angle at the reflective surface 54. To put it another way, the angle θ3 of the reflective surface 54 is set such that the angle of incidence of light incident on the reflective surface 54 is greater than the critical angle.

[0082] Furthermore, the light incident on the incident surface 53 is set so that it is not totally reflected at the incident surface 53. In other words, the angle θ2 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.

[0083] The angle between the element surface of the optical element 50 and the plane of the aerial image 2, and the distance between the element surface of the optical element 50 and the plane of the aerial image 2, can be adjusted by optimally setting the angle θ1 of the light incident on the optical element 50, the refractive index of the optical element 50, the angle θ2 of the incident surface 53 of the optical element 50, and the angle θ3 of the reflective surface 54 of the optical element 50.

[0084] [1-2-2] Regarding the effects of ambient light Next, the effect of ambient light incident on the aerial display device 1 will be explained. Ambient light is incident on the aerial display device 1. Ambient light is light that is incident on the aerial display device 1 from outside the aerial display device 1. Ambient light includes sunlight and light from indoor lighting fixtures. Ambient light is unpolarized natural light.

[0085] Figure 13 illustrates the behavior of ambient light incident on the aerial display device 1.

[0086] In a plan view, ambient light incident on the area occupied by the display element 20 of the aerial display device 1 (including the area of ​​point "A" in Figure 13 of the orientation control element 40) passes through the optical element 50 and is incident on the orientation control element 40. The ambient light incident on the orientation control element 40 is absorbed by the light-shielding member 44 included in the orientation control element 40. Therefore, it is possible to suppress the reflection of ambient light incident on the area occupied by the display element 20 of the aerial display device 1 from inside the aerial display device 1 and its emission from the upper surface of the aerial display device 1.

[0087] In a plan view, ambient light incident on the region of the aerial display device 1 other than the region occupied by the display element 20 (including the region of point "B" in Figure 13 of the orientation control element 40) passes through the optical element 50 and is incident on the orientation control element 40. The ambient light incident on the orientation control element 40 is absorbed by the light-shielding member 44 included in the orientation control element 40. Therefore, it is possible to suppress the reflection of ambient light incident on the region of the aerial display device 1 other than the region occupied by the display element 20 from the inside of the aerial display device 1 and its emission from the top surface of the aerial display device 1.

[0088] As a result, it is possible to suppress the deterioration of the quality of the aerial image 2 displayed by the aerial display device 1 due to ambient light incident on the aerial display device 1.

[0089] Furthermore, light incident on the aerial display device 1 from below is absorbed by the light absorption layer 30. Therefore, it is possible to suppress the deterioration of the quality of the aerial image 2 displayed by the aerial display device 1 due to light incident on the aerial display device 1 from below.

[0090] [1-3] Variant Figure 14 is a cross-sectional view of an aerial display device 1 according to a modified example. The display element 20 and the orientation control element 40 may be bonded together with a transparent adhesive 21.

[0091] [1-4] Comparative Examples Next, we will describe the aerial display device 1A related to the comparative example. Figure 15 is an exploded view of the aerial display device 1A according to the comparative example. Figure 16 is a partial cross-sectional view of the aerial display device 1A according to the comparative example, along the X direction.

[0092] The aerial display device 1A comprises an illumination element 10, a display element 20, an orientation control element 40, an optical element 50, and a housing 60. The illumination element 10, the display element 20, the orientation control element 40, and the optical element 50 are arranged in this order along the Z direction and are parallel to each other.

[0093] The comparative example aerial display device 1A does not include the light-absorbing layer 30 shown in the first embodiment. The area of ​​the orientation control element 40 is approximately the same as the area of ​​the display element 20. The area of ​​the optical element 50 is larger than the area of ​​the orientation control element 40. The length of the optical element 50 in the X direction is longer than the length of the orientation control element 40 in the X direction.

[0094] The housing 60 has a rectangular shape and includes four side plates and a bottom plate. The housing 60 is made of, for example, black resin. A rectangular opening 62 is provided in the bottom plate of the housing 60. Light emitted from the display element 20 passes through the opening 62. The area of ​​the opening 62 is approximately the same as the area of ​​the orientation control element 40.

[0095] Figure 17 illustrates the behavior of ambient light incident on the aerial display device 1A.

[0096] In a plan view, ambient light incident on the area occupied by the display element 20 of the aerial display device 1A (including the area of ​​point "A" in Figure 17 of the orientation control element 40) passes through the optical element 50 and is incident on the orientation control element 40. The ambient light incident on the orientation control element 40 is absorbed by the light-shielding member 44 included in the orientation control element 40. Therefore, it is possible to suppress the reflection of ambient light incident on the area occupied by the display element 20 of the aerial display device 1A from inside the aerial display device 1A and its emission from the upper surface of the aerial display device 1A.

[0097] Of the ambient light incident on the aerial display device 1A, the light component that reaches the bottom plate of the housing 60 is diffusely reflected by the bottom plate of the housing 60. The light component diffusely reflected by the housing 60 is reflected towards the observer by the optical element 50 and is visible to the observer.

[0098] Figure 18 shows the display element image and Optical element This is a diagram illustrating the image. The display element image is the image displayed on the display surface of the display element 20. Optical element The image is a real image formed by the optical element 50. (Aerial image) That is the case.

[0099] In addition to the display element image, a double frame formed by ambient light is visible in the aerial image. The frame shifted to the right in Figure 18 is visible based on ambient light diffusely reflected to the right at point "B" in Figure 17. The frame shifted to the left in Figure 18 is visible based on ambient light diffusely reflected to the left at point "B" in Figure 17. Thus, when ambient light is diffusely reflected inside the aerial display device 1A, the quality of the aerial image generated by the aerial display device 1A deteriorates.

[0100] In contrast, in the first embodiment, the component surface (the upper surface of the orientation control element 40) that is positioned opposite the optical element 50 is expanded. This makes it possible to suppress the reflection of ambient light inside the aerial display device.

[0101] [1-5] Effects of the first embodiment In the first embodiment, the aerial display device 1 includes a display element 20 for displaying an image, an orientation control element 40 positioned to receive light from the display element 20 and transmitting the oblique light component of the light from the display element 20, an optical element 50 positioned to receive light from the orientation control element 40 and reflecting the light from the orientation control element 40 to the opposite side of the orientation control element 40 to form an aerial image in the air, and a housing 60 configured to surround the optical element 50 and fix the optical element 50. The area of ​​the element positioned opposite the optical element 50 (the orientation control element 40 in this embodiment) is set to be larger than the area of ​​the optical element 50. That is, an element with a uniform surface is positioned opposite the optical element 50.

[0102] The aerial display device 1 is exposed to ambient light depending on the operating environment. This ambient light is unnecessary for forming the aerial image 2. According to the first embodiment, it is possible to suppress the reflection of ambient light incident on the aerial display device 1 and its emission from the aerial display device 1. This suppresses the deterioration of the quality of the aerial image 2 generated by the aerial display device 1. As a result, an aerial display device 1 capable of improving display quality can be realized.

[0103] Furthermore, a light-absorbing layer 30 is provided on the bottom surface of the orientation control element 40, and the light-absorbing layer 30 has an opening 31 through which light from the display element 20 passes. This allows the light-absorbing layer 30 to absorb light components that are unnecessary for displaying the aerial image 2. Therefore, deterioration of the quality of the aerial image 2 can be suppressed.

[0104] Furthermore, the aerial display device 1 can display an aerial image in the air by reflecting the light emitted from the display element 20 with the optical element 50. In addition, the aerial display device 1 can display an aerial image in the direction directly in front of it.

[0105] Furthermore, when observer 3 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 aligned), observer 3 can perceive the aerial image. Also, when observer 3 moves their viewpoint along the Y direction with both eyes parallel to or nearly parallel to the X direction, they can always perceive the aerial image. In addition, a wider field of view can be achieved when observer 3's eyes are parallel to or nearly parallel to the X direction.

[0106] Furthermore, multiple elements constituting the aerial display device 1 can be arranged in parallel. This makes it possible to realize an aerial display device 1 that can be miniaturized in the Z direction.

[0107] In the first embodiment, the orientation control element 40 is positioned opposite the optical element 50. The area of ​​the orientation control element 40 is made larger than the area of ​​the optical element 50. In other configurations of the aerial display device 1, if the element opposite the optical element 50 is an element other than the orientation control element 40, the area of ​​the element positioned opposite the optical element is set to be larger than the area of ​​the optical element. This makes it possible to obtain the effects of this embodiment.

[0108] [2] Second embodiment In the second embodiment, an anti-reflective layer 80 is provided on the upper surface of the element facing the optical element 50.

[0109] Figure 19 is a cross-sectional view of the aerial display device 1 according to the second embodiment of the present invention, along the X direction. Figure 19 corresponds to a cross-sectional view at the position of line AA' in Figure 2. The aerial display device 1 according to the second embodiment includes an anti-reflective layer 80 in addition to the configuration of the first embodiment.

[0110] The anti-reflective layer 80 is provided on the orientation control element 40. The area of ​​the anti-reflective layer 80 is the same as the area of ​​the orientation control element 40. The anti-reflective layer 80 has the function of suppressing the reflection of light incident on itself. The anti-reflective layer 80 is made of a transparent material and is composed of, for example, multiple layers with different refractive indices stacked on top of each other. The anti-reflective layer 80 is also called a reflection suppression layer.

[0111] Figure 20 illustrates the reflection of light inside the aerial display device 1. In the configuration example shown in Figure 20, there is no anti-reflective layer 80, and the upper surface of the orientation control element 40 faces the optical element 50.

[0112] External light entering the aerial display device 1 passes through the optical element 50. A portion of the light that passes through the optical element 50 is reflected from the upper surface of the orientation control element 40. A portion of the light that has been repeatedly reflected between the optical element 50 and the orientation control element 40 (the reflected light in Figure 20) passes through the optical element 50 and is emitted towards the observer. Therefore, the quality of the aerial image 2 may deteriorate due to internal reflection of external light.

[0113] In contrast, in this embodiment, an anti-reflective layer 80 is provided on the surface facing the optical element 50. Therefore, it is possible to suppress internal reflection of ambient light that has passed through the optical element 50. This improves the quality of the aerial image 2.

[0114] [3] Third embodiment In the third embodiment, a transparent support member 32 is positioned opposite the entire surface of the optical element 50. Furthermore, a light-absorbing layer 30 is placed on the bottom surface of the support member 32. The support member 32 and the light-absorbing layer 30 are used to suppress the diffusion and reflection of ambient light inside the aerial display device 1 and its emission towards the observer.

[0115] [3-1] Configuration of the aerial display device 1 Figure 21 is an exploded view of the aerial display device 1 according to the third embodiment of the present invention. Figure 22 is a cross-sectional view of the aerial display device 1 shown in Figure 21 along the X direction. Figure 22 corresponds to the cross-sectional view at the position of line AA' in Figure 2.

[0116] The aerial display device 1 comprises an illumination element 10, a display element 20, an orientation control element 40, a light absorption layer 30, a support member 32, an optical element 50, and a housing 60. The illumination element 10, the display element 20, the orientation control element 40, the light absorption layer 30, the support member 32, and the optical element 50 are arranged in this order along the Z direction and are arranged parallel to each other. The illumination element 10, the display element 20, and the orientation control element 40 are fixed in desired positions by fixing members (not shown) so as to be spaced apart from each other.

[0117] The area of ​​the orientation control element 40 is approximately the same as the area of ​​the display element 20. The length of the orientation control element 40 in the X direction is approximately the same as the length of the display element 20 in the X direction. The length of the orientation control element 40 in the Y direction is approximately the same as the length of the display element 20 in the Y direction.

[0118] The light-absorbing layer 30 has a rectangular opening 31. The opening 31 has the same area as the orientation control element 40 and exposes the orientation control element 40. The light-absorbing layer 30 is provided on the bottom surface of the support member 32 and is attached to the bottom surface of the support member 32. The outer circumference of the light-absorbing layer 30 extends to the outer circumference of the support member 32.

[0119] The support member 32 is provided above the orientation control element 40 and is bonded to the orientation control element 40, for example, using a transparent adhesive. The support member 32 is made of a transparent material and transmits light. Glass or a transparent resin (including acrylic resin) can be used as the support member 32.

[0120] The area of ​​the support member 32 is larger than the area of ​​the orientation control element 40. The length of the support member 32 in the X direction is longer than the length of the orientation control element 40 in the X direction. In Figure 22, the right end of the support member 32 is located to the right of the right end of the orientation control element 40, and the left end of the support member 32 is located to the left of the left end of the orientation control element 40. The length of the support member 32 in the Y direction is longer than the length of the orientation control element 40 in the Y direction.

[0121] The optical element 50 is positioned opposite the support member 32. The area of ​​the optical element 50 is larger than the area of ​​the orientation control element 40 and smaller than the area of ​​the support member 32. The length of the optical element 50 in the X direction is longer than the length of the orientation control element 40 in the X direction and shorter than the length of the support member 32 in the X direction. In Figure 22, the right end of the optical element 50 is located between the right end of the orientation control element 40 and the right end of the support member 32, and the left end of the optical element 50 is located between the left end of the orientation control element 40 and the left end of the support member 32. The length of the optical element 50 in the Y direction is longer than the length of the orientation control element 40 in the Y direction and shorter than the length of the support member 32 in the Y direction.

[0122] The area of ​​the opening at the bottom of the housing 60 is set to be the same as the area of ​​the support member 32. The support member 32 is fitted into the opening at the bottom of the housing 60. The housing 60 and the support member 32 are bonded together with a transparent adhesive.

[0123] [3-2] Regarding the effects of ambient light Next, we will explain the effect of ambient light incident on the aerial display device 1. Figure 23 is a diagram illustrating the appearance of ambient light incident on the aerial display device 1.

[0124] In a plan view, ambient light incident on the area occupied by the display element 20 of the aerial display device 1 (including the area of ​​point "A" in Figure 23 of the orientation control element 40) passes through the optical element 50 and is incident on the orientation control element 40. The ambient light incident on the orientation control element 40 is absorbed by the light-shielding member 44 included in the orientation control element 40. Therefore, it is possible to suppress the reflection of ambient light incident on the area occupied by the display element 20 of the aerial display device 1 from inside the aerial display device 1 and its emission from the upper surface of the aerial display device 1.

[0125] In a plan view, ambient light incident on the area of ​​the aerial display device 1 other than the area occupied by the display element 20 (including the area of ​​point "B" in Figure 23 of the support member 32) passes through the optical element 50 and is incident on the support member 32. The light incident on the support member 32 is absorbed by the light absorption layer 30. Therefore, ambient light incident on the area of ​​the aerial display device 1 other than the area occupied by the display element 20 is prevented from being reflected inside the aerial display device 1 and emitted from the top surface of the aerial display device 1.

[0126] As a result, it is possible to suppress the deterioration of the quality of the aerial image 2 displayed by the aerial display device 1 due to ambient light incident on the aerial display device 1.

[0127] Furthermore, light incident on the aerial display device 1 from below is absorbed by the light absorption layer 30. Therefore, it is possible to suppress the deterioration of the quality of the aerial image 2 displayed by the aerial display device 1 due to light incident on the aerial display device 1 from below.

[0128] [3-3] Variant Figure 24 is a cross-sectional view of an aerial display device 1 according to a modified example. The display element 20 and the orientation control element 40 may be bonded together with a transparent adhesive 21. The orientation control element 40 and the support member 32 may be bonded together with a transparent adhesive 22.

[0129] [3-4] Effects of the third embodiment According to the third embodiment, it is possible to suppress the deterioration of the quality of the aerial image 2 displayed by the aerial display device 1. Other effects are the same as in the first embodiment.

[0130] It is also possible to apply the second embodiment to the third embodiment. That is, an anti-reflective layer 80 may be further provided on the upper surface of the support member 32.

[0131] Furthermore, in the third embodiment, the aerial display device 1 may be configured without the orientation control element 40.

[0132] [4] Other examples In the above embodiment, the display element 20 and the optical element 50 are arranged in parallel. However, the embodiment is not limited to this, and the display element 20 may be arranged diagonally with respect to the optical element 50. The angle between the display element 20 and the optical element 50 is set to a range greater than 0 degrees and less than 45 degrees.

[0133] In the above embodiment, the left side of the optical element 52 is defined as the incident surface 53, and the right side is defined as the reflective surface 54. However, the embodiment is not limited to this, and the incident surface 53 and the reflective surface 54 may be configured in reverse. In this case, the operation of the aerial display device 1 described in the embodiment will also be reversed left and right.

[0134] In the above embodiment, a liquid crystal display element is used as an example for the display element 20, but it is not limited to this. The display element 20 can also be a self-emissive organic EL (electroluminescence) display element or a micro-LED (light-emitting diode) display element. A micro-LED display element is a display element that emits R (red), G (green), and B (blue) light, which constitute the pixels, using LEDs. When a self-emissive display element 20 is used, the illumination element 10 is not required.

[0135] The present invention is not limited to the embodiments described above, and can be modified in various ways during implementation without departing from its essence. Furthermore, each embodiment may be combined as appropriate, and in that case, the combined effects can be obtained. Moreover, the above embodiments include various inventions, and various inventions can be extracted by selecting combinations from the multiple constituent elements disclosed. For example, if the problem can be solved and effects obtained even if some constituent elements are deleted from all the constituent elements shown in the embodiment, then the configuration with these deleted constituent elements can be extracted as an invention. [Explanation of Symbols]

[0136] 1...Aerial display device, 2...Aerial image, 3...Observer, 10...Illumination element, 11...Light source unit, 12...Light guide plate, 13...Reflective sheet, 20...Display element, 21,22...Adhesive, 30...Light absorption layer, 31...Aperture, 32...Support member, 40...Orientation control element, 41,42...Substrate, 43...Transparent member, 44...Light shielding member, 50...Optical element, 51...Substrate, 52...Optical element, 53...Incident surface, 54...Reflective surface, 60...Housing, 61,62...Aperture, 70...Control unit, 70A...Display processing unit, 70B...Information processing unit, 71...Storage unit, 72...Input / output interface, 73...Display unit, 74...Input unit, 75...Bus, 80...Anti-reflective layer.

Claims

1. A display element that displays an image, An orientation control element is positioned to receive light from the display element and transmits the oblique light component of the light from the display element, An optical element is positioned to receive light from the orientation control element, and reflects the light from the orientation control element to the opposite side of the orientation control element, thereby forming an aerial image in the air. A housing is configured to surround the optical element and to fix the optical element, It is equipped with, The optical element includes a planar substrate and a plurality of optical elements provided beneath the substrate, each extending in a first direction and arranged in a second direction perpendicular to the first direction. Each of the plurality of optical elements is composed of a triangular prism, and each is inclined with respect to the normal direction of the substrate and has an incident surface and a reflective surface that are in contact with each other. The area of ​​the orientation control element is larger than the area of ​​the optical element. Aerial display device.

2. The outer circumference of the orientation control element extends to the housing. The aerial display device according to claim 1.

3. The orientation control element is provided on its bottom surface and further comprises a light-absorbing layer having an opening through which light from the display element passes and which absorbs light. The aerial display device according to claim 1.

4. The outer periphery of the light-absorbing layer extends to the outer periphery of the orientation control element. The aerial display device according to claim 3.

5. The device further comprises an anti-reflective layer provided on the upper surface of the orientation control element. The aerial display device according to claim 1.

6. A display element for displaying an image, An orientation control element is positioned to receive light from the display element and transmits the oblique light component of the light from the display element, A transparent support member that transmits light from the orientation control element, The support member is provided with a light-absorbing layer having an opening through which light from the orientation control element passes, and which absorbs light. An optical element is positioned to receive light from the orientation control element, and reflects the light from the orientation control element to the opposite side of the orientation control element, thereby forming an aerial image in the air. A housing is configured to surround the optical element and to fix the optical element, It is equipped with, The optical element includes a planar substrate and a plurality of optical elements provided beneath the substrate, each extending in a first direction and arranged in a second direction perpendicular to the first direction. Each of the plurality of optical elements is composed of a triangular prism, and each is inclined with respect to the normal direction of the substrate and has an incident surface and a reflective surface that are in contact with each other. The area of ​​the support member is larger than the area of ​​the optical element. Aerial display device.

7. The outer circumference of the support member extends to the housing. The aerial display device according to claim 6.

8. The outer periphery of the light-absorbing layer extends to the outer periphery of the support member. The aerial display device according to claim 6.

9. The support member further comprises an anti-reflective layer provided on its upper surface. The aerial display device according to claim 6.

10. The orientation control element includes a plurality of transparent members and a plurality of light-shielding members arranged alternately. The plurality of light-shielding members are inclined with respect to the direction normal to the orientation control element. The aerial display device according to claim 1 or 6.

11. The display element, the orientation control element, and the optical element are arranged parallel to each other. The aerial display device according to claim 1 or 6.

Images