JP7841378B2 - aerial display device - Google Patents

Description

This invention relates to an aerial display device.

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 might include a two-sided corner reflector array, where two-sided corner reflectors are arranged in an array. This reflects light emitted from the display surface of the display element, forming a real image in mid-air. The display method using a two-sided corner reflector array is aberration-free and allows for the display of a real image (aerial image) in a plane-symmetrical position.

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 numerous vertical, strip-shaped planar light reflecting sections at a constant pitch inside a transparent flat plate, and the first and second light control panels are arranged so that their planar light reflecting sections are orthogonal to each other. The optical elements in Patent Documents 1 and 2 generate an aerial image by reflecting light emitted from a display element twice using orthogonal reflective surfaces.

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; however, it is difficult to recognize a good aerial image by observing it from the direction normal to the optical element.

Japanese Patent Publication No. 2011-191404 Japanese Patent Publication No. 2011-175297

This invention provides an aerial display device capable of improving display quality.

According to a first aspect of the present invention, an aerial display device is provided, comprising: a display element for displaying an image; a light correction element positioned to receive light emitted from the display element and refracting the light emitted from the display element toward a normal vector perpendicular to the plane; and an optical element positioned to receive light emitted from the light correction element and reflecting the light emitted from the light correction element toward the opposite side of the light correction element, thereby forming an aerial image in the air.

According to a second aspect of the present invention, an aerial display device according to the first aspect is provided, wherein the optical element reflects the light component of the light emitted from the light correction element that spreads to a first plane perpendicular to the plane toward the normal direction perpendicular to the plane, and the light correction element refracts the light component of the light emitted from the display element that spreads to a second plane that is both within the plane and perpendicular to the first plane toward the normal direction.

According to a third aspect of the present invention, an aerial display device according to the first or second aspect is provided, wherein the light correcting element has a plurality of first lens surfaces provided on its bottom surface and a plurality of second lens surfaces provided on its top surface, the plurality of first lens surfaces constituting a convex lens, each extending in a first direction and aligned in a second direction perpendicular to the first direction, and the plurality of second lens surfaces constituting a convex lens, each extending in the first direction and aligned in the second direction.

According to a fourth aspect of the present invention, an aerial display device according to the third aspect is provided, wherein the optical element reflects light incident obliquely from the light correction element in the normal direction.

According to a fifth aspect of the present invention, an aerial display device according to the fourth aspect is provided, wherein the optical element includes a planar substrate and a plurality of optical elements provided beneath the substrate, each extending in the second direction and arranged in the first direction, and each of the plurality of optical elements is inclined with respect to the normal of the substrate and has an incident surface and a reflective surface that are in contact with each other.

According to a sixth aspect of the present invention, an aerial display device according to the first or second aspect is provided, wherein the display element, the light correction element, and the optical element are arranged parallel to each other.

According to a seventh aspect of the present invention, an aerial display device according to the first or second aspect is provided, further comprising an orientation control element disposed between the light correction element and the optical element, which transmits a portion of the light emitted from the display element.

According to an eighth aspect of the present invention, an aerial display device according to the seventh 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 of the orientation control element.

According to a ninth aspect of the present invention, an aerial display device according to the first or second aspect is provided, further comprising a light-emitting illumination element, wherein the display element is arranged to receive light from the illumination element and is composed of a liquid crystal display element.

According to the present invention, it is possible to provide an aerial display device capable of improving display quality.

Figure 1 is a perspective view of an aerial display device according to an embodiment of the present invention. Figure 2 is a side view of the aerial display device shown in Figure 1 in the XZ plane. Figure 3 is a side view in the YZ plane of the aerial display device shown in Figure 1. Figure 4 is a perspective view of the light correction element shown in Figure 1. Figure 5 is a side view in the YZ plane illustrating the configuration of the optical correction element. Figure 6A is a plan view of the orientation control element shown in Figure 1. Figure 6B is a cross-sectional view of the orientation control element along the line A-A' in Figure 6A. Figure 7 is a perspective view of the optical element shown in Figure 1. Figure 8 is a block diagram of the aerial display device. Figure 9 is a perspective view illustrating the reflection of light in an optical element. Figure 10 is a side view of the XZ plane illustrating the reflection of light in an optical element. Figure 11 is a side view of the YZ plane illustrating the reflection of light in an optical element. Figure 12 illustrates the angular conditions of the incident and reflective surfaces in an optical element. Figure 13 is a perspective view illustrating an example of an aerial image generated by an aerial display device. Figure 14 is a side view of the YZ plane illustrating the operation of the optical correction element. Figure 15 is a schematic diagram illustrating how an observer views an aerial image. Figure 16 is a schematic diagram illustrating how an observer views an aerial image. Figure 17 is a perspective view illustrating the operation of the aerial display device corresponding to Figure 16. Figure 18 is a schematic diagram illustrating how an observer views an aerial image. Figure 19 is a perspective view illustrating the operation of the aerial display device corresponding to Figure 18. Figure 20 is a perspective view illustrating the operation of an aerial display device according to a comparative example. Figure 21 is a side view in the XZ plane of an aerial display device according to a modified example.

The embodiments will be described below with reference to the drawings. However, the drawings are schematic or conceptual, and the dimensions and proportions shown in each drawing are not necessarily identical to those of actual objects. Furthermore, even when the same part is represented between different drawings, the relationships between dimensions and proportions may differ. 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 defined 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.

[1] Configuration of the aerial display device 1 Figure 1 is a perspective view of the aerial display device 1 according to an 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 side view of the aerial display device 1 shown in Figure 1 in the XZ plane. Figure 3 is a side view of the aerial display device 1 shown in Figure 1 in the YZ plane.

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 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 constituting the aerial display device 1. An aerial image is a real image formed in the air.

The aerial display device 1 comprises an illumination element (also called a backlight) 10, a display element 20, a light correction element 30, an orientation control element 40, and an optical element 50. The illumination element 10, display element 20, light correction element 30, orientation control element 40, and optical element 50 are arranged in this order along the Z-direction and are parallel to each other. The illumination element 10, display element 20, light correction element 30, orientation control element 40, and optical element 50 are fixed at desired positions by fixing members (not shown) with a desired spacing between them.

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.

The light source unit 11 is positioned facing the side surface of the light guide plate 12. The light source unit 11 emits light toward the side surface of the light guide plate 12. The light source unit 11 includes multiple 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 include a member (including a prism sheet and a diffusion sheet) on the upper surface of the light guide plate 12 to improve its optical properties.

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; 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 the desired image on its display surface.

The light correction element 30 receives light emitted from the display element 20. The light correction element 30 has the function of refracting light in the Y direction. Furthermore, the light correction element 30 refracts the light component of the light emitted from the display element 20 that spreads in the YZ plane toward the normal direction perpendicular to the element surface of the light correction element 30. The element surface refers to a virtual plane that extends in the in-plane direction of the light correction element 30. The term "element surface" has the same meaning as "in-plane." The same meaning applies to the element surfaces of other elements. The light correction element 30 has multiple convex lens surfaces provided on its bottom surface and multiple convex lens surfaces provided on its top surface. The detailed configuration of the light correction element 30 will be described later.

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 with an angle θ ₁ with respect to the normal direction in the XZ plane, and to block light components outside of the above angular range. The detailed configuration of the orientation control element 40 will be described later.

The optical element 50 reflects light incident obliquely from the bottom side to the top side. Furthermore, the optical element 50 reflects the light component of the light emitted from the orientation control element 40 that spreads in the XZ plane towards the normal plane perpendicular to the element surface of the optical element 50. The optical element 50 forms an aerial image 2 in the air in front of the aerial display device 1. The detailed configuration of the optical element 50 will be described later. The aerial image 2 is parallel to the element surface of the optical element 50 and is a two-dimensional image. An observer 3 standing in front of the optical element 50 can see the aerial image 2.

[1-1] Configuration of the light correction element 30 Figure 4 is a perspective view of the light correction element 30 shown in Figure 1. Figure 4 also shows an enlarged view of a part of the light correction element 30. The enlarged view in Figure 4 is a side view in the YZ plane.

The light correction element 30 has a plurality of first lens surfaces 31 provided on its bottom surface and a plurality of second lens surfaces 32 provided on its top surface.

The multiple first lens surfaces 31 each extend in the X direction and are arranged in a line in the Y direction. Each first lens surface 31 is composed of a columnar convex lens. In other words, the multiple first lens surfaces 31 constitute a lenticular lens.

The multiple second lens surfaces 32 each extend in the X direction and are arranged in a line in the Y direction. Each second lens surface 32 is composed of a columnar convex lens. In other words, the multiple second lens surfaces 32 constitute a lenticular lens.

The first lens surface 31 and the second lens surface 32 have the same pitch. Here, "pitch" refers to the width in the Y direction of each of the first lens surface 31 and the second lens surface 32. The first lens surface 31 and the second lens surface 32 are positioned at the same location (completely overlapping) in a plan view.

The light correcting element 30 is made of glass or a transparent resin (including acrylic resin).

Figure 5 is a side view in the YZ plane illustrating the configuration of the optical correction element 30.
The first lens surface 31 has a radius of curvature R1, a principal point H1, and a focal length f1. The second lens surface 32 has a radius of curvature R2, a principal point H2, and a focal length f2. The thickness of the light correcting element 30 is T, and the pitch of the first lens surface 31 and the second lens surface 32 is P.

The optical axes of the first lens surface 31 and the second lens surface 32 coincide. The radii of curvature R1 and R2 are set to be the same. The focal lengths f1 and f2 are calculated from the radii of curvature R1 and R2, respectively. The thickness T of the optical correction element 30 is set based on the radii of curvature R1, R2, and the focal lengths f1 and f2. The pitch P can be set arbitrarily. The radii of curvature R1, R2, focal lengths f1 and f2, thickness T, pitch P, and refractive index of the optical correction element 30 are appropriately set according to the required characteristics of the optical correction element 30.

The light correction element 30 configured in this way refracts light incident from the bottom side through multiple first lens surfaces 31, and then further refracts it through multiple second lens surfaces 32. The light correction element 30 then refracts and focuses the light component radiating from a certain point on the display element 20 in the YZ plane toward the normal direction perpendicular to the element surface of the light correction element 30.

[1-2] Configuration of the orientation control element 40 Figure 6A is a plan view of the orientation control element 40 shown in Figure 1. Figure 6B is a cross-sectional view of the orientation control element 40 along the line A-A' in Figure 6A.

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

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.

Multiple transparent members 43 and multiple light-shielding members 44 are provided with 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.

The transparent member 43 extends in an oblique direction at an angle θ ₁ 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 at an angle θ ₁ in the XZ plane. The transparent member 43 transmits light.

The light-shielding member 44 extends in an oblique direction at an angle θ ₁ 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 θ ₁ 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.

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

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, for example, a resin mixed with black dye or pigment.

The orientation control element 40 configured in this way can transmit display light such that the light intensity peaks in the oblique direction at an angle θ ₁ with respect to the normal direction. 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.

As a modified example, the orientation control element 40 may be placed between the illumination element 10 and the display element 20. Alternatively, the orientation control element 40 may be omitted to configure the aerial display device 1.

[1-3] 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.

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 shape.

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 so 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.

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 light incident on the incident surface 53 from the outside within the optical element 52. The incident surface 53 and the reflecting surface 54 have an angle _θp .

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. As the transparent material constituting the base material 51 and the optical element 52, glass or a transparent resin (including acrylic resin) can be used.

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

[1-4] 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 60, a storage unit 61, an input/output interface (input/output IF) 62, a display unit 63, a sensing device 64, and an input unit 65. The control unit 60, the storage unit 61, and the input/output interface 62 are connected to each other via a bus 66.

The input/output interface 62 is connected to the display unit 63, the sensing device 64, and the input unit 65. The input/output interface 62 performs interface processing for each of the display unit 63, the sensing device 64, and the input unit 65 according to predetermined standards.

The display unit 63 comprises an illumination element 10 and a display element 20. The display unit 63 displays an image.

The sensing device 64 detects objects (target objects) present in the detection area. The sensing device 64 emits infrared light into a spatial area (detection area) that includes part or all of the aerial image 2 generated by the aerial display device 1, and detects the infrared light reflected by the target object. The sensing device 64 includes a light-emitting unit that emits infrared light and a light-receiving unit (sensor) that detects infrared light.

The control unit 60 is composed of one or more processors, such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The control unit 60 implements various functions by executing programs stored in the storage unit 61. The control unit 60 includes a display processing unit 60A, a position calculation unit 60B, and an information processing unit 60C.

The display processing unit 60A controls the operation of the display unit 63 (specifically, the illumination element 10 and the display element 20). The display processing unit 60A controls the on/off state of the illumination element 10. The display processing unit 60A transmits an image signal to the display element 20, causing the display element 20 to display an image.

The position calculation unit 60B controls the operation of the sensing device 64. The position calculation unit 60B causes the sensing device 64 to form a detection area consisting of infrared light. Based on multiple detection signals sent from the sensing device 64, the position calculation unit 60B calculates the position of the object to be detected within the detection area. For example, based on multiple detection signals, the position calculation unit 60B calculates the position within the detection area where the user touched. A known method (such as the principle of triangulation) is used to calculate the position.

The information processing unit 60C generates the image to be displayed by the aerial display device 1. The information processing unit 60C can use image data stored in the storage unit 61. The information processing unit 60C may also acquire image data from an external source using a communication function (not shown).

The storage unit 61 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 61 stores the program executed by the control unit 60. The storage unit 61 stores various data necessary for controlling the control unit 60. The storage unit 61 also stores image data displayed by the aerial display device 1.

The input unit 65 includes a touch panel and buttons, and receives information entered by the user. The information processing unit 60C can select an image to display on the display unit 63 based on the information received by the input unit 65.

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

The arrows in Figures 2 and 3 indicate the optical path. As shown in Figures 2 and 3, light emitted from the display element 20 passes through the light correction element 30 and then enters the orientation control element 40. The operation of the light correction element 30 will be described later. Of the light emitted from the display element 20, the light component at angle _θ1 (including the light 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, and displays the aerial image 2 in the air.

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 viewed 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 viewed by observer 3 with both eyes parallel to the Y direction. Note that the refractive effect of the light correction element 30 is not considered in Figure 11.

Light emitted from an arbitrary point "o" on the display surface of the display element 20 enters the incident surface 53 of the optical element 50 and reaches the reflective surface 54. Light arriving at an angle greater than the critical angle with respect to the normal direction of the reflective surface 54 undergoes total internal reflection at the reflective surface 54 and is emitted from the plane opposite the side of the optical element 52 of the optical element 50. The critical angle is the smallest angle of incidence beyond which total internal reflection occurs. The critical angle is the angle with respect to the perpendicular to the incident surface.

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 this light is imaged in the air to generate an aerial image.

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.

In other words, the condition for observer 3 to perceive the aerial image is that both of observer 3's eyes are parallel to or nearly parallel to the X direction (for example, ±10 degrees relative to the X direction). Furthermore, if observer 3 moves their viewpoint along the Y direction while both of their eyes are parallel to or nearly parallel to the X direction, they can always perceive the aerial image.

Figure 12 illustrates the angular conditions of the incident surface 53 and the reflective surface 54 in the optical element 50.

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 reflecting surface 54 with respect to the Z direction, and _θp be the angle between the incident surface 53 and the reflecting surface 54. The angle _θp is expressed by the following equation (1).
θ _p = θ ₂ + θ ₃ ...(1)

Light emitted from the display element 20 at an angle θ ₁ enters the incident surface 53. Assume the refractive index of the optical element 50 material is _np and the refractive index of air is 1. The angle of incidence at the incident surface 53 is θ ₄ and the angle of refraction is θ _5. The angle of incidence at the reflective surface 54 is θ ₆ and the angle of reflection is θ ₇ (= θ ₆ ). The angle of incidence at the upper surface of the optical element 50 is θ ₈ and the angle of refraction is θ _9. The angle of refraction θ ₉ is the exit angle. The exit angle θ ₉ is expressed by the following equation (2).
θ ₉ = sin ^-1 (n _p *sin (sin ^-1 ((1/n _p ) * sin (90° - (θ ₁ + θ ₂ ))) + θ ₂ +2θ ₃ -90°)) ... (2)

The critical angle at the reflective surface 54 is expressed by the following equation (3).
Critical angle <θ ₆ (=θ ₇ )
Critical angle = sin ^-1 (1/n _p )...(3)
In other words, the angle of incidence θ ₆ 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 θ ₃ of the reflective surface 54 is set so that the angle of incidence of light incident on the reflective surface 54 is greater than the critical angle.

Furthermore, the light incident on the incident surface 53 is set so that it is not totally reflected at the incident surface 53. That is, 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.

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.

Figure 13 is a perspective view illustrating an example of an aerial image generated by the aerial display device 1. The aerial display device 1 comprises a rectangular housing, and multiple elements constituting the aerial display device 1 are housed within this housing. The aerial display device 1 has a light-emitting surface 1A on its uppermost surface, and emits light from this light-emitting surface 1A to generate the aerial image 2. In Figure 13, a button is shown as an example of the aerial image 2.

The sensing device 64 included in the aerial display device 1 forms a detection area 64A in the spatial region including the aerial image 2. The detection area 64A is formed using infrared light. When the observer 3's finger 3A touches the aerial image 2, the sensing device 64 detects the observer 3's finger 3A. The position calculation unit 60B calculates the position of the observer 3's finger 3A based on multiple detection signals sent from the sensing device 64. This allows the aerial display device 1 to display button 2 towards the observer 3 and detect that the observer 3 has pressed button 2.

Next, the operation of the light correction element 30 will be explained. Figure 14 is a side view of the YZ plane illustrating the operation of the light correction element 30. Figure 14 shows the display element 20 and the light correction element 30 separately. Figure 14 also shows the tracking of a light ray.

The orientation control element 40 controls the orientation of light in relation to the spread of light in the XZ plane. Since the light-shielding member 44 of the orientation control element 40 extends in the Y direction, the orientation control element 40 has almost no control over the orientation of light in the YZ plane. Because the orientation control element 40 has virtually no effect on the action of light in the YZ plane, it is omitted from the side view of the YZ plane in Figure 14. Similarly, the optical element 50 controls reflection in relation to the spread of light in the XZ plane. Since the optical element 52 of the optical element 50 extends in the Y direction, the optical element 50 has almost no control over reflection of light in the YZ plane. Because the optical element 50 has virtually no effect on the action of light in the YZ plane, it is omitted from the side view of the YZ plane in Figure 14.

The display element 20 emits light toward the light correction element 30. Figure 14 shows the light emitted from point "o" on the display element 20, and this light is emitted from the display element 20 with a predetermined spread. Light incident from the display element 20 to the light correction element 30 is refracted by multiple first lens surfaces 31, and the light refracted by the multiple first lens surfaces 31 is refracted by multiple second lens surfaces 32. The light refracted twice by the light correction element 30 forms an image at point "o'" in the air. Point "o'" is the position where the airborne image 2 is formed. For example, the distance from point "o" to the light correction element 30 is the same as the distance from the light correction element 30 to point "o'". The position of point "o'" is appropriately set by adjusting the distance between the display element 20 and the light correction element 30, and the optical characteristics of the light correction element 30 shown in Figure 5.

Furthermore, since the light correction element 30 does not function as a lens for the spread of light in the XZ plane, it hardly refracts light rays in the XZ plane. In other words, the light correction element 30 has almost no effect on light rays in the XZ plane.

Figure 15 is a schematic diagram illustrating how observer 3 views the aerial image 2. Figure 15 is a side view in the YZ plane and also shows the view from the front of the aerial display device 1 as seen by observer 3. The line connecting observer 3's eyes is parallel to the X direction.

The sensing device 64 included in the aerial display device 1 forms a detection area 64A in the spatial region containing the aerial image 2. The aerial image 2 is formed at the same position as the detection area 64A. The observer 3 views the aerial image 2 at the same position as the detection area 64A in a planar view. The operation in Figure 15 corresponds to the operation in Figure 13.

Figure 16 is a schematic diagram illustrating how observer 3 views the aerial image 2. Figure 16 is a side view in the YZ plane, and shows the view from observer 3 at a position offset in the Y direction from the front of the aerial display device 1.

In Figure 16, observer 3 perceives the light component of the left-hand region of Figure 16 from the light refracted by the light correction element 30. As a result, observer 3 perceives the aerial image 2 at the same position as the detection region 64A in a planar view.

Figure 17 is a perspective view illustrating the operation of the aerial display device 1, corresponding to Figure 16. The sensing device 64 forms a detection area 64A at a fixed position in space. An observer 3, observing the aerial display device 1 from a position offset in the Y direction from its front, views the aerial image 2 in front of the aerial display device 1. This allows the sensing device 64 to detect the observer's finger 3A more accurately.

Figure 18 is a schematic diagram illustrating how observer 3 views the aerial image 2. Figure 18 is a side view in the YZ plane, and also shows the view from observer 3 at a position offset in the opposite direction to the Y direction from the front of the aerial display device 1.

In Figure 18, observer 3 perceives the light component in the right-hand region of Figure 18 from the light refracted by the light correction element 30. As a result, observer 3 perceives the aerial image 2 at the same position as the detection region 64A in a planar view.

Figure 19 is a perspective view illustrating the operation of the aerial display device 1, corresponding to Figure 18. The sensing device 64 forms a detection area 64A at a fixed position in space. An observer 3, observing the aerial display device 1 from a position offset in the opposite direction to the front of the aerial display device 1, views the aerial image 2 in front of the aerial display device 1. This allows the sensing device 64 to detect the observer's finger 3A more accurately.

[3] Comparative Example Figure 20 is a perspective view illustrating the operation of the aerial display device 1 according to the comparative example.

The aerial display device 1 in the comparative example does not have a light correction element 30. In the absence of the light correction element 30, the light emitted from the display element 20 is hardly refracted in the YZ plane. That is, the light emitted from the display element 20 passes through the optical element 50 almost linearly in the YZ plane.

When observer 3 views the aerial display device 1 from a position shifted in the Y direction from the front of the device, the aerial image 2 moves in the Y direction along with observer 3's line of sight. Similarly, when observer 3 views the aerial display device 1 from a position shifted in the opposite direction to the Y direction from the front of the device, the aerial image 2 moves in the opposite direction to the Y direction along with observer 3's line of sight.

The sensing device 64 forms a detection area 64A at a fixed position in space. In this case, the two types of aerial images 2 described above do not overlap with the detection area 64A. Therefore, even if observer 3 touches the button (represented by the aerial image 2) with their finger 3A, the sensing device 64 may not be able to detect observer 3's finger 3A.

In contrast, the aerial display device 1 according to this embodiment includes an optical correction element 30 that refracts light in the YZ plane. The operation of the aerial display device 1 according to this embodiment is as described above. Thus, this embodiment can solve the problems of the comparative example.

[4] Modified Version Next, a modified version of the aerial display device 1 will be described. Figure 21 is a side view of the modified aerial display device 1 in the XZ plane. The light correction element 30 may be placed between the orientation control element 40 and the optical element 50. The modified aerial display device 1 can also achieve the same operation as the embodiment described above.

[5] Effects of the Embodiment According to the embodiment of the present invention, an aerial image 2 can be displayed in the air by reflecting the light emitted from the display element 20 with the optical element 50. Furthermore, the aerial image 2 can be displayed in the front direction of the aerial display device 1. In addition, an aerial display device capable of improving display quality can be realized.

Furthermore, the light correction element 30 refracts light in the YZ plane toward the normal side of the aerial display device 1. Therefore, even if the observer 3 moves their line of sight along the Y direction (the direction in which the optical element 52 of the optical element 50 extends), the aerial image 2 can be displayed in the same position as when viewed from the front of the aerial display device 1.

Furthermore, the aerial display device 1 includes a sensing device 64. The sensing device 64 forms a detection region 64A in the spatial area including the aerial image 2, and can detect objects present in this detection region 64A.

Furthermore, even if observer 3 moves their gaze along the Y-direction, the aerial display device 1 can overlay the aerial image 2 onto the detection area 64A. This allows for more accurate detection of observer 3's finger 3A when the observer touches the aerial image 2 with their finger 3A.

Furthermore, when observer 3's eyes are 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 while their eyes are parallel to or nearly parallel to the X direction, they can always perceive the aerial image. Additionally, a wider field of view can be achieved when observer 3's eyes are parallel to or nearly parallel to the X direction.

Furthermore, the 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.

In the above embodiment, the display element 20 and the optical element 50 are arranged parallel to each other. However, the invention is not limited to this configuration, and the display element 20 may be arranged diagonally to the optical element 50. The angle between the display element 20 and the optical element 50 is set within a range greater than 0 degrees and less than 45 degrees. In this modified example, the light correction element 30 is arranged parallel to the display element 20, and the orientation control element 40 is omitted.

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.

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, and various types of display elements can be used. For example, the display element 20 can be a self-emissive organic electroluminescent (EL) display element or a micro-LED (Light Emitting Diode) display element. A micro-LED display element is a display element that uses LEDs to emit light for the R (red), G (green), and B (blue) components that make up the pixels. When using a self-emissive display element 20, the illumination element 10 is not required.

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, combined effects can be obtained. Moreover, the above embodiments include various inventions, and various inventions can be extracted by selecting combinations from the multiple disclosed constituent elements. 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 embodiments, then the configuration with these deleted constituent elements can be extracted as an invention.

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, 30…Light correction element, 31…First lens surface, 32…Second lens surface, 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…Control unit, 60A…Display processing unit, 60B…Position calculation unit, 60C…Information processing unit, 61…Storage unit, 62…Input/output interface, 63…Display unit, 64…Sensing device, 64A…Detection area, 65…Input unit, 66…Bus.

Claims (8)

A display element that displays an image,
A light correction element is positioned to receive the light emitted from the display element and refracts the light emitted from the display element toward the normal vector perpendicular to the plane,
An optical element is positioned to receive light emitted from the aforementioned light correcting element, and reflects the light emitted from the aforementioned light correcting element to the opposite side of the light correcting element, thereby forming an aerial image in the air.
It is equipped with ,
The display element, the light correction element, and the optical element are arranged parallel to each other.
Aerial display device. The optical element reflects the light component of the light emitted from the light correction element that spreads to a first plane perpendicular to the plane toward the normal direction perpendicular to the plane.
The aerial display device according to claim 1, wherein the light correction element refracts the light component of the light emitted from the display element that spreads within the plane and to a second plane perpendicular to the first plane toward the normal side. The light correcting element has a plurality of first lens surfaces provided on its bottom surface and a plurality of second lens surfaces provided on its top surface.
The plurality of first lens surfaces constitute a convex lens, each extending in a first direction and aligned in a second direction perpendicular to the first direction.
The aerial display device according to claim 1 or 2, wherein the plurality of second lens surfaces constitute a convex lens, each extending in the first direction and aligned in the second direction. The aerial display device according to claim 3, wherein the optical element reflects light incident obliquely from the light correction element in the normal direction. The optical element includes a planar substrate and a plurality of optical elements provided beneath the substrate, each extending in the second direction and arranged in the first direction.
The aerial display device according to claim 4, wherein each of the plurality of optical elements is inclined with respect to the normal of the substrate and has an incident surface and a reflective surface that are in contact with each other. The aerial display device according to claim 1 or 2, further comprising an orientation control element disposed between the light correcting element and the optical element, which transmits a portion of the light emitted from the display element. The orientation control element includes a plurality of transparent members and a plurality of light-shielding members arranged alternately.
The aerial display device according to claim 6 , wherein the plurality of light-shielding members are inclined with respect to the normal of the orientation control element. It further comprises an illumination element that emits light,
The aerial display device according to claim 1 or 2, wherein the display element is arranged to receive light from the illumination element and is composed of a liquid crystal display element.