Aerial image display device

Abstract

The aerial image display device includes: a display device having a display surface; a first concave mirror that reflects the image light emitted from the display surface in a direction different from a direction toward the display device; a second concave mirror that reflects the image light reflected by the first concave mirror in a direction different from a direction toward the first concave mirror and forms a real aerial image; and a light shielding member located between the display device and the second concave mirror and not located in an optical path of image light reaching the aerial image from the display surface via the first concave mirror and the second concave mirror.

Description

Technical Field

[0001] The present disclosure relates to an aerial image display device. Background Art

[0002] Conventionally, an aerial image display device such as that described in Patent Document 1 is known.

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2018 / 043673 Summary of the invention

[0006] The aerial image display device disclosed herein comprises:

[0007] A display device having a display surface;

[0008] a first concave mirror, which reflects the image light emitted from the display surface in a direction different from the direction toward the display device;

[0009] a second concave mirror, which reflects the image light reflected by the first concave mirror in a direction different from the direction toward the first concave mirror, and forms an image as a real aerial image; and

[0010] The light shielding member is located between the display device and the second concave mirror and is not located in an optical path of the image light that reaches the aerial image from the display surface via the first concave mirror and the second concave mirror.

[0011] In addition, the aerial image display device of the present disclosure includes:

[0012] A display device having a display surface;

[0013] a first concave mirror, which reflects the image light emitted from the display surface in a direction different from the direction toward the display device;

[0014] a convex mirror, which reflects the image light reflected by the first concave mirror in a direction different from a direction toward the first concave mirror;

[0015] a second concave mirror, which reflects the image light reflected by the convex mirror in a direction different from the direction toward the convex mirror, and forms an image as a real aerial image; and

[0016] a light shielding member located between the display device and the second concave mirror and not located in an optical path of the image light that reaches the aerial image from the display surface via the first concave mirror, the convex mirror, and the second concave mirror,

[0017] The convex mirror is located between the light shielding member and the second concave mirror.

[0018] In addition, the aerial image display device of the present disclosure includes:

[0019] A display device having a display surface;

[0020] a first concave mirror, which reflects the image light emitted from the display surface in a direction different from the direction toward the display device;

[0021] a second concave mirror, which reflects the image light reflected by the first concave mirror in a direction different from the direction toward the first concave mirror, and forms an image as a real aerial image; and

[0022] A light-collecting member is located between the display device and the first concave mirror, and collimates the image light emitted from the display surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The objects, features and advantages of the present disclosure will become more apparent from the following detailed description and the accompanying drawings.

[0024] Figure 1 It is a cross-sectional view showing the main part structure of the aerial image display device involved in one embodiment of the present disclosure.

[0025] Figure 2 It is used to illustrate Figure 1 A cross-sectional view of the first concave mirror of the aerial image display device showing the curvature of the first concave mirror.

[0026] Figure 3 It is a cross-sectional view showing the main structure of an aerial image display device according to another embodiment of the present disclosure.

[0027] Figure 4 This is a cross-sectional view showing a main part structure of an aerial image display device according to still another embodiment of the present disclosure. DETAILED DESCRIPTION

[0028] The conventional aerial image display device described in Patent Document 1 uses optical elements such as a beam splitter and a reflector to form an aerial image of image light emitted from a display device as a real image.

[0029] In existing aerial image display devices, optical elements direct part of the image light toward an unexpected direction or location, thereby generating a double image that is visually recognized by the user's eyes or a virtual image that is visually recognized by the user's eyes. As a result, the visibility of the aerial image is sometimes reduced.

[0030] Hereinafter, the embodiments of the present disclosure will be described with reference to the accompanying drawings. The figures referred to below represent the main structural elements of the aerial image display device involved in the embodiments. The display device involved in the embodiments may also have well-known structural elements such as a housing and an optical system support member that are not shown in the figure. The figures referred to below are schematic, and the dimensional ratios on the figures are not necessarily consistent with the actual ones.

[0031] Figure 1 is a cross-sectional view showing a main structure of an aerial image display device according to an embodiment of the present disclosure. Figure 2 It is used to illustrate Figure 1 A cross-sectional view of the first concave mirror of the aerial image display device showing the curvature of the first concave mirror.

[0032] like Figure 1 As shown, the aerial image display device 1 of this embodiment includes a display device 2, a first concave mirror 3, a second concave mirror 5 and a light shielding member 6.

[0033] The display device 2 has a display surface 2a, and displays, on the display surface 2a, an image propagated as image light L. That is, the display device 2 emits the image light L from the display surface 2a.

[0034] The display device 2 may be a transmissive display device. The transmissive display device may be, for example, a liquid crystal display device configured to include a backlight and a liquid crystal panel. The backlight may be a direct-under type backlight having a plurality of light sources arranged in two dimensions on the back side of the liquid crystal panel. The backlight may be a side-light type backlight having a plurality of light sources arranged on the periphery of the liquid crystal panel. The side-light type backlight may have a lens array, a light guide plate, a diffusion plate, etc. for uniformly illuminating the liquid crystal panel. The light source of the backlight may be, for example, a light emitting diode (LED) element, a cold cathode fluorescent lamp, a halogen lamp, a xenon lamp, etc. The liquid crystal panel may be a well-known liquid crystal panel. Well-known liquid crystal panels may be, for example, liquid crystal panels of the IPS (In-Plane Switching) method, the FFS (Fringe Field Switching) method, the VA (Vertical Alignment) method, the ECB (Electrically Controlled Birefringence) method, etc.

[0035] The transmissive display device is not limited to the liquid crystal display device. The transmissive display device may be, for example, a MEMS (Micro Electro Mechanical Systems) shutter display device including a backlight and a MEMS shutter.

[0036] The display device 2 is not limited to a transmissive display device, and may be a self-luminous display device including a light-emitting element such as an LED element, an organic electroluminescence (OEL) element, an organic light-emitting diode (OLED) element, or a semiconductor laser (LD) element.

[0037] The first concave mirror 3 and the second concave mirror 5 constitute a reflection optical system that forms an image of the image light L emitted from the display device 2 as an aerial image R. Hereinafter, the first concave mirror 3 and the second concave mirror 5 may be collectively described as a reflection optical system 8 .

[0038] The first concave mirror 3 is located on the optical path of the image light L emitted from the display device 2. The first concave mirror 3 is configured to reflect the image light L emitted from the display device 2 in a direction different from the direction toward the display device 2. An adjustment member for adjusting the relative spatial configuration (the distance from the display surface 2a, the inclination angle relative to the display surface 2a, etc.) relative to the display device 2 may also be provided on the first concave mirror 3. The adjustment member may, for example, also include a supporting member such as a rod provided on the back side of the first concave mirror 3, an axial member provided on the supporting member for rotating the supporting member and the first concave mirror 3, a sliding mechanism for parallel movement of the supporting member and the first concave mirror 3, etc. The adjustment member may also be adjusted manually, or may be electrically adjusted by a stepping motor, etc.

[0039] The second concave mirror 5 is located on the optical path of the image light L reflected by the first concave mirror 3. The second concave mirror 5 is configured to reflect the image light L reflected by the first concave mirror 3 in a direction different from the direction toward the first concave mirror 3, and to form an image as a real image in the air R. An adjustment member for adjusting the relative spatial configuration (the distance from the first concave mirror 3, the tilt angle relative to the first concave mirror 3, etc.) with respect to the first concave mirror 3 may also be provided on the second concave mirror 5. The adjustment member may also be the same structure as the adjustment member provided on the first concave mirror 3.

[0040] The first concave mirror 3 and the second concave mirror 5 have a reflecting surface 3a and a reflecting surface 5a, respectively. The first concave mirror 3 and the second concave mirror 5 may be free-form mirrors in which the shapes of the reflecting surfaces 3a and 5a are free-form surfaces. When the first concave mirror 3 and the second concave mirror 5 are free-form mirrors, the distortion of the aerial image R can be reduced by appropriately designing the shapes of the reflecting surfaces 3a and 5a.

[0041] The free-form surface defining the reflection surfaces 3a and 5a may also be an XY polynomial surface (also referred to as an SPS XYP surface) defined by the following equations (1) and (2). The XY polynomial surface is expanded into a polynomial of the highest order of 10 added to the reference conical surface. Therefore, in equations (1) and (2), the sum of m and n is less than 10. In equation (1), z is the verticality of the surface parallel to the z-axis (also referred to as the optical axis), c is the vertex curvature, k is the cone constant, and r satisfies r 2 =x 2 +y 2 , Cj is the monomial x m y n The coefficient of .

[0042] [Number 1]

[0043]

[0044] [Number 2]

[0045]

[0046] The shading member 6 is located between the display device 2 and the second concave mirror 5. The shading member 6 is not located on the optical path of the image light L that reaches the aerial image R from the display surface 2a via the first concave mirror 3 and the second concave mirror 5. The shading member 6 can block the image light L' that directly goes from the display surface 2a to the second concave mirror 5. Therefore, the aerial image display device 1 can effectively prevent the image light L emitted from the display surface 2a from reaching the second concave mirror 5 without passing through the first concave mirror 3 and being reflected by the second concave mirror 5 in an undesired direction and position. As a result, it is possible to prevent the generation of double images that are visually recognized by the eyes of the user 10, or the visual recognition of virtual images by the eyes of the user 10, and reduce the reduction in the visual recognizability of the aerial image R.

[0047] In recent years, the viewing angle of the image light L in the display device 2 is close to ±180°, so it is easy to generate image light L' directly from the display surface 2a toward the second concave mirror 5. As a result, double images and virtual images are easy to occur, but the aerial image display device disclosed in the present invention can reduce or eliminate the influence of such problems.

[0048] The light shielding member 6 may be located between the display device 2 and the second concave mirror 5, at a position close to the display device 2. In this case, the light shielding member 6 can be prevented from being enlarged, and the image light L' directly directed from the display surface 2a to the second concave mirror 5 can be shielded. The light shielding member 6 may also be in contact with the display device 2.

[0049] The light shielding member 6 may also be located along at least a portion of the periphery of the display surface 2a, for example, a portion of the display surface 2a close to the second concave mirror 5. When the display surface 2a is rectangular, the light shielding member 6 may also be located along one or both end edges of the display surface 2a close to the second concave mirror 5. In addition, the light shielding member 6 may extend from an imaginary plane including the display surface 2a along the emission direction of the image light L from the display surface 2a. The light shielding member 6 may also extend in a direction perpendicular to the display surface 2a. In this case, it is possible to suppress the enlargement of the light shielding member 6 and effectively shield the image light L' that directly goes from the display surface 2a to the second concave mirror 5.

[0050] The shading member 6 can be made of, for example, metal materials such as aluminum, magnesium, copper, zinc, and alloy materials such as stainless steel, copper-zinc alloy, and aluminum-copper alloy. The surface of the shading member 6 facing the display surface 2a (also referred to as the shading surface) 6a can also be roughened, and the shading surface 6a can also have a fine concave-convex structure, and a light absorption layer can be formed on the shading surface 6a. In this case, the image light L reaching the shading surface 6a is difficult to be reflected by the shading surface 6a, and the generation of stray light can be more effectively suppressed. As a result, the reduction in the visual recognition of the aerial image R can be more effectively suppressed. The arithmetic mean roughness of the above-mentioned fine concave-convex structure can also be about 1nm to 100nm, or about 10nm to 55nm (about 1 / 10 of the central visible light wavelength of 555nm), but is not limited to these ranges.

[0051] The light absorbing layer formed on the light shielding surface 6a can be composed of a resin material containing a light absorbing material (such as epoxy resin, silicone resin, acrylic resin, etc.). The light absorbing material can also be an inorganic pigment, and the inorganic pigment can also be a carbon-based pigment such as carbon black, a nitride-based pigment such as titanium black, a metal oxide-based pigment such as Cr-Fe-Co, Cu-Co-Mn (manganese), Fe-Co-Mn, Fe-Co-Ni-Cr, etc. The surface of the light absorbing layer can also have a fine concave-convex structure, and the image light L reaching the light shielding surface 6a is more easily absorbed by the light absorbing layer located on the light shielding surface 6a. The fine concave-convex structure can also be a surface roughness including a surface roughness (arithmetic mean roughness) of about 1 / 10 (about 55nm) or less of about 550nm, which is the center frequency of visible light, or a surface roughness (arithmetic mean roughness) of about 55nm or less. For example, the arithmetic mean roughness of the fine concavo-convex structure may be approximately 1 nm to 100 nm, or approximately 10 nm to 55 nm, but is not limited to these ranges.

[0052] The light shielding member 6 may also be a structure capable of electrically adjusting the transmittance. For example, the light shielding member 6 may also be a liquid crystal shutter (also referred to as LCW (LC window)) using a polymer liquid crystal. In this case, by setting the voltage applied to the liquid crystal shutter to a cut-off voltage (voltage for light shielding), it is possible to function as the light shielding member 6. In addition, by setting the voltage applied to the liquid crystal shutter to an intermediate voltage between the cut-off voltage and the on-voltage, the transmittance (light shielding property) of the light shielding member 6 can be controlled. The transmittance of the light shielding member 6 may also be about 0% to about 90%, or about 5% to about 80%, but is not limited to these ranges.

[0053] In addition, the light shielding member 6 may also be an electrophoretic display device (EPD). EPD is also called electronic paper. EPD has the following advantages: it does not require a backlight and can maintain its state even if no current flows, so it has low power consumption and a wide operating temperature range of about 0°C to 50°C. In addition, the operating speed of EPD is about 250ms (milliseconds), which is slower than the liquid crystal shutter, but it is a problem-free operating speed for the light shielding member 6. That is, this is because once the light shielding member 6 is given the light shielding property, it basically needs to maintain this state.

[0054] like Figure 1 As shown, the height of the light shielding member 6 (the height from the display surface 2a) is set to a height that does not overlap with the optical path of the image light L that forms the aerial image R. In other words, the height of the light shielding member 6 can be said to be a height that does not affect the formation of the aerial image R or a height at which a part of the aerial image R is not lost. In addition, the height of the light shielding member 6 can also be said to be a height that does not enter the image light propagation space that connects the entire surface of the reflection surface 3a of the first concave mirror 3 and the entire surface of the reflection surface 5a of the second concave mirror 5. Figure 3 In the case of the structure of, the height of the light shielding member 6 can also be said to be the height that does not enter the image light propagation space connecting the entire surface of the reflection surface 3a of the first concave mirror 3, the entire surface of the reflection surface 4a of the convex mirror 4, and the entire surface of the reflection surface 5a of the second concave mirror 5. In addition, the height of the light shielding member 6 can also be about 0.1 mm to 30 mm, but is not limited to this range.

[0055] In addition, the light shielding member 6 may be a structure in which the shortest distance between the light shielding member 6 and the optical path of the image light L is longer than the wavelength of visible light (about 360nm to 830nm, that is, about 0.36μm to 0.83μm). In the case where the shortest distance between the light shielding member 6 and the optical path of the image light L is shorter than the wavelength of visible light, the light closest to the light shielding member 6 in the image light L is diffracted and expanded at the end of the light shielding member 6, so that it is easy to cause undesirable conditions such as deformation of the end of the aerial image R and reduction of brightness at the end of the aerial image R. On the other hand, in the case of the above-mentioned structure, it is possible to suppress the light closest to the light shielding member 6 in the image light L from diffracting and expanding at the end of the light shielding member 6, and it is possible to suppress undesirable conditions such as deformation of the end of the aerial image R and reduction of brightness at the end of the aerial image R. The shortest distance between the light shielding member 6 and the optical path of the image light L may be about 1μm or more, and may also be more than twice the maximum wavelength of the visible light wavelength (about 0.83μm). The upper limit of the shortest distance between the light shielding member 6 and the optical path of the image light L is not particularly limited, but in order to suppress the increase in size of the aerial image display device 1, it may be about 10 mm, about 3 mm, or about 1 mm.

[0056] In the aerial image display device 1, since the reflective optical system 8 does not include an optical element (e.g., a beam splitter, a polarization filter, etc.) that transmits a portion of the image light L, it is possible to suppress a reduction in the brightness of the aerial image R. Alternatively, according to the aerial image display device 1, since the brightness of the image displayed on the display surface 2a can be reduced while maintaining sufficient brightness of the aerial image R, the power consumption of the aerial image display device 1 can be reduced.

[0057] like Figure 1 As shown, the aerial image display device 1 includes a control device 9. The control device 9 is connected to each structural element of the aerial image display device 1 to control each structural element. The structural elements controlled by the control device 9 include the display device 2. The control device 9 may also have: the function of turning on and off the display device 2; the function of sending an image signal to the display device 2; the function of adjusting the brightness, chromaticity, frame rate, etc. of the image, etc. In addition, in the case where the display device 2 is provided with a heat dissipation component or a cooling component, the control device 9 may also have the function of adjusting the temperature of the heat dissipation component or the cooling component. The control device 9 may also control the adjustment components of the first concave mirror 3 and the second concave mirror 5.

[0058] The control device 9 may also be configured to include more than one processor. The processor may also include a general-purpose processor configured to read a specific program to execute a specific function, and a dedicated processor specifically used for a specific process. A dedicated processor may also include an ASIC (Application Specific Integrated Circuit). The processor may also include a PLD (Programmable Logic Device). The PLD may also include an FPGA (Field-Programmable Gate Array). The control device 9 may also be a SoC (System-on-a-Chip) or SiP (System In a Package) configured to cooperate with more than one processor.

[0059] like Figure 1 As shown, the aerial image display device 1 may also be a structure in which the inclination angle θ2 of the imaginary plane P of the display surface 2a relative to the second concave mirror 5 is greater than the inclination angle θ1 of the imaginary plane P relative to the first concave mirror 3. The inclination angle θ2 refers to the angle formed by the imaginary plane P and the tangent plane T2 of the second concave mirror 5. The tangent plane T2 refers to the plane that is connected to the reflecting surface 5a of the second concave mirror 5 at the vertex O2 (also called the origin of the free-form surface) of the reflecting surface 5a. The inclination angle θ1 refers to the angle formed by the imaginary plane P and the tangent plane T1 of the first concave mirror 3. The tangent plane T1 refers to the plane that is connected to the reflecting surface 3a of the first concave mirror 3 at the vertex O1 of the reflecting surface 3a. In the aerial image display device 1, by making the inclination angle θ2 greater than the inclination angle θ1, most of the image light L emitted from the display surface 2a is directed toward the first concave mirror 3, so that the image light L is easily incident on the first concave mirror 3 and is difficult to be directly incident on the second concave mirror 5. As a result, double images and virtual images are less likely to occur, and the reduction in visibility of the aerial image R can be effectively reduced. Figure 1 In the case of a structure of , θ1 may be approximately 30° to 60°, and θ2 may be approximately 70° to 110°, but are not limited to these ranges.

[0060] The aerial image display device 1 may have a structure in which the curvature Sa1 is greater than the curvature Sa2 when the curvature of the reflection surface 3a of the first concave mirror 3 is set to Sa1 and the curvature of the reflection surface 5a of the second concave mirror 5 is set to Sa2. Since the curvature Sa1 is relatively large, the first concave mirror 3 that reflects the image light L emitted from the display device 2 in a direction different from the direction toward the display device 2 can be arranged close to the display device 2. As a result, the space occupied by the display device 2 and the reflection optical system 8 can be reduced, and the aerial image display device 1 can be miniaturized. Furthermore, by miniaturizing the aerial image display device 1, the optical path length of the image light L between the display surface 2a of the display device 2 and the reflection surface 5a of the second concave mirror 5 can be shortened, thereby suppressing the loss of the image light L caused by unexpected scattering, interference, etc. As a result, the display quality of the aerial image display device 1 can be improved.

[0061] In addition, if Figure 2 As shown, in the cross section along the optical axis of the image light L incident on the first concave mirror 3, the length of the line segment LS passing through the center of the reflecting surface 3a and connecting the two ends is set to 2×H, and the maximum value (also called the maximum depth) of the length of the point on the reflecting surface 3a and the line segment LS along the direction of the optical axis OA is set to D MAX When the curvature Sa1 of the first concave mirror 3 is D MAX / H definition. In D MAX When / H changes depending on the method of obtaining the cross section, D can also be changed when the position of the cross section is changed. MAX The maximum value of / H is defined as the curvature Sa1. The curvature Sa2 is also defined in the same manner as the curvature Sa1.

[0062] In the direction parallel to the imaginary imaging plane of the aerial image R ( Figure 1 In the up and down direction in the image display device 1), when the second concave mirror 5 is observed from the back side of the second concave mirror 5, the second concave mirror 5 may also overlap with the display device 2 and the first concave mirror 3. In this case, the space occupied by the display device 2 and the reflective optical system 8 can be reduced, so the aerial image display device 1 can be miniaturized. As a result, since the optical path length of the image light L inside the aerial image display device 1 can be shortened, the loss of the image light L caused by unexpected scattering, interference, etc. can be suppressed. Furthermore, the display quality of the aerial image display device 1 can be improved.

[0063] Next, an aerial image display device according to another embodiment of the present disclosure will be described. Figure 31 is a cross-sectional view showing the main structure of an aerial image display device according to another embodiment of the present disclosure. The aerial image display device 1A of this embodiment is different from the aerial image display device 1 of the above-mentioned embodiment in the configuration of the reflective optical system, and the other configurations are the same as those of the aerial image display device 1 of the above-mentioned embodiment, so the description of the same structure will be omitted.

[0064] The aerial image display device 1A of the present embodiment includes a display device 2 , a first concave mirror 3 , a convex mirror 4 , a second concave mirror 5 , and a light shielding member 6 .

[0065] The first concave mirror 3, the convex mirror 4, and the second concave mirror 5 constitute a reflection optical system that forms an image of the image light L emitted from the display device 2 as an aerial image R. Hereinafter, the first concave mirror 3, the convex mirror 4, and the second concave mirror 5 may be collectively described as a reflection optical system 8A.

[0066] The first concave mirror 3 is located on the optical path of the image light L emitted from the display device 2. The first concave mirror 3 is configured to reflect the image light L emitted from the display device 2 in a direction different from the direction toward the display device 2. An adjustment member for adjusting the relative spatial configuration (the distance from the display surface 2a, the inclination angle relative to the display surface 2a, etc.) relative to the display device 2 may also be provided on the first concave mirror 3. The adjustment member may, for example, include a supporting member such as a rod provided on the back side of the first concave mirror 3, an axial member provided on the supporting member for rotating the supporting member and the first concave mirror 3, a sliding mechanism for parallel movement of the supporting member and the first concave mirror 3, etc. The adjustment member may also be adjusted manually or electrically by a stepping motor or the like.

[0067] The convex mirror 4 is located on the optical path of the image light L reflected by the first concave mirror 3. The convex mirror 4 is located between the display device 2 and the second concave mirror 5. The convex mirror 4 is configured to reflect the image light L reflected by the first concave mirror 3 in a direction different from the direction toward the first concave mirror 3. An adjustment member for adjusting the relative spatial configuration (the distance from the first concave mirror 3, the inclination angle relative to the first concave mirror 3, etc.) relative to the first concave mirror 3 may also be provided on the convex mirror 4. The adjustment member may also be the same structure as the adjustment member provided on the first concave mirror 3.

[0068] The second concave mirror 5 is located on the optical path of the image light L reflected by the convex mirror 4. The second concave mirror 5 is configured to reflect the image light L reflected by the convex mirror 4 in a direction different from the direction toward the convex mirror 4, and to form an image as a real image in the air R. The second concave mirror 5 may also include an adjustment member for adjusting the relative spatial configuration (the distance from the convex mirror 4, the tilt angle relative to the convex mirror 4, etc.) with respect to the convex mirror 4. The adjustment member may also be the same structure as the adjustment member provided on the first concave mirror 3.

[0069] The first concave mirror 3, the convex mirror 4, and the second concave mirror 5 have a reflecting surface 3a, a reflecting surface 4a, and a reflecting surface 5a, respectively. The first concave mirror 3, the convex mirror 4, and the second concave mirror 5 may be free-form mirrors whose shapes of the reflecting surfaces 3a, 4a, and 5a are represented by the above equations (1) and (2). In this case, by appropriately designing the shapes of the reflecting surfaces 3a, 4a, and 5a, the distortion of the aerial image R can be reduced.

[0070] The light shielding member 6 is located between the display device 2 and the second concave mirror 5. The light shielding member 6 is not located in the optical path of the image light L that reaches the aerial image R from the display surface 2a via the first concave mirror 3, the convex mirror 4, and the second concave mirror 5, that is, the optical path of the light that forms the aerial image R. Therefore, since the light shielding member 6 is not arranged at a position that hinders the imaging of the aerial image R, the light shielding member 6 itself does not deteriorate the visual recognition of the aerial image R. The light shielding member 6 can block the image light L' that directly goes from the display surface 2a to the second concave mirror 5. The light shielding member 6 of the aerial image display device 1A can have the same structure as the light shielding member 6 of the aerial image display device 1.

[0071] The light shielding member 6 can shield the image light L' that is directed directly from the display surface 2a to the second concave mirror 5. Therefore, the aerial image display device 1A can prevent the image light L emitted from the display surface 2a from reaching the second concave mirror 5 without passing through the first concave mirror 3 and the convex mirror 4 and being unexpectedly reflected by the second concave mirror 5. As a result, it is possible to prevent the occurrence of a double image that is visually recognized by the eyes of the user 10, or a virtual image that is visually recognized by the eyes of the user 10, and reduce the reduction in the visibility of the aerial image R.

[0072] Furthermore, even if the image light L' that is directed directly from the display surface 2a toward the second concave mirror 5 is not fully shielded by the light shielding member 6, the convex mirror 4 can shield at least a portion of the image light L'. Therefore, the aerial image display device 1A can more effectively prevent a portion of the image light L emitted from the display surface 2a from reaching the second concave mirror 5 without passing through the first concave mirror 3 and the convex mirror 4 and being reflected by the second concave mirror 5 in an undesired direction and location. As a result, the reduction in the visual recognizability of the aerial image R can be more effectively reduced. In addition, in Figure 3 In the case of a structure of , θ1 may be approximately 10° to 35°, and θ2 may be approximately 30° to 70°, but are not limited to these ranges.

[0073] In the aerial image display device 1A, since the reflective optical system 8A does not include an optical element (e.g., a beam splitter, a polarization filter, etc.) that transmits a portion of the image light L, it is possible to suppress a decrease in the brightness of the aerial image R. Alternatively, according to the aerial image display device 1A, since it is possible to reduce the brightness of the image displayed on the display surface 2a while maintaining sufficient brightness of the aerial image R, it is possible to reduce power consumption of the aerial image display device 1A.

[0074] The aerial image display device 1A may also be a structure in which the inclination angle θ2 of the imaginary plane P including the display surface 2a relative to the second concave mirror 5 is greater than the inclination angle θ1 of the imaginary plane P relative to the first concave mirror 3. The inclination angles θ1 and θ2 are defined in the same manner as above. The aerial image display device 1A makes the inclination angle θ2 greater than the inclination angle θ1, so that most of the image light L emitted from the display surface 2a is directed toward the first concave mirror 3, so that the image light L is easily incident on the first concave mirror 3 and is difficult to be directly incident on the second concave mirror 5. As a result, it is not easy to generate double images and virtual images, and the reduction in the visual recognition of the aerial image R can be effectively reduced.

[0075] In the aerial image display device 1A, the reflective optical system 8A is configured to include three mirrors, thereby increasing the degree of freedom of relative spatial arrangement of the display device 2 and the second concave mirror 5. As a result, the inclination angle θ2 of the virtual plane P relative to the second concave mirror 5 can be set to 90 degrees or an angle close to 90 degrees, and a portion of the image light L emitted from the display surface 2a can be suppressed from propagating directly toward the second concave mirror 5.

[0076] In the aerial image display device 1A, the following structure may be adopted: when the curvature of the reflection surface 3a of the first concave mirror 3 is set to Sa1, the curvature of the convex mirror 4 is set to Sb, and the curvature of the reflection surface 5a of the second concave mirror 5 is set to Sa2, the curvature Sa1 is greater than the curvature Sa2, and the curvature Sa2 is greater than the curvature Sb. The curvatures Sa1, Sb, and Sa2 are defined in the same manner as described above. By making the curvature Sa1 greater than the curvature Sa2 and the curvature Sb, the first concave mirror 3 that reflects the image light L emitted from the display device 2 in a direction different from the direction toward the display device 2 can be arranged close to the display device 2. As a result, the space occupied by the display device 2 and the reflective optical system 8A can be reduced, and the aerial image display device 1A can be miniaturized. In addition, by miniaturizing the aerial image display device 1A, the optical path length of the image light L between the display surface 2a of the display device 2 and the reflection surface 5a of the second concave mirror 5 can be shortened, thereby suppressing the loss of the image light L caused by undesired scattering, interference, etc. As a result, the display quality of the aerial image display device 1A can be improved.

[0077] The convex mirror 4 easily amplifies the expansion of the image light L and easily increases the distortion of the aerial image R. In the aerial image display device 1A, since the curvature Sa2 is smaller than the curvature Sa1 and the curvature Sa2, the increase of the distortion generated in the aerial image R by the convex mirror 4 can be suppressed. As a result, the display quality of the aerial image R is improved. In addition, the curvature Sb of the convex mirror 4 is relatively small, so that the expansion of the image light L reflected by the convex mirror 4 can be suppressed. As a result, the enlargement of the second concave mirror 5 that reflects the image light L reflected by the convex mirror 4 can be suppressed.

[0078] In the direction parallel to the imaginary imaging plane of the aerial image R ( Figure 3 When the second concave mirror 5 is observed from the back side of the second concave mirror 5 (in the up and down direction in the image), the second concave mirror 5 may overlap with the display device 2, the first concave mirror 3, and the convex mirror 4. In this case, the space occupied by the display device 2 and the reflective optical system 8A can be reduced, so the aerial image display device 1A can be miniaturized. As a result, the optical path length of the image light L inside the aerial image display device 1A can be shortened, so the loss of the image light L caused by unexpected scattering, interference, etc. can be suppressed. Furthermore, the display quality of the aerial image display device 1A can be improved.

[0079] exist Figure 3 In the aerial image display device 1A shown, the light shielding member 6 may have a structure capable of electrically adjusting light transmittance. For example, the light shielding member 6 may be a liquid crystal shutter or EPD using polymer liquid crystal as described above.

[0080] In addition, Figure 3 In the aerial image display device 1A shown, the light shielding member 6 may be configured such that the shortest distance between the light shielding member 6 and the optical path of the image light L is longer than the wavelength of visible light (about 360 nm to 830 nm, i.e., about 0.36 μm to 0.83 μm). When the shortest distance between the light shielding member 6 and the optical path of the image light L is shorter than the wavelength of visible light, the light closest to the light shielding member 6 in the image light L is diffracted and expanded at the end of the light shielding member 6, so that it is easy to cause the end of the aerial image R to be deformed, the brightness of the end of the aerial image R to be reduced, and other unfavorable conditions. On the other hand, in the case of the above-mentioned structure, the light closest to the light shielding member 6 in the image light L can be suppressed from being diffracted and expanded at the end of the light shielding member 6, and the deformation of the end of the aerial image R, the brightness of the end of the aerial image R, and other unfavorable conditions can be suppressed. The shortest distance between the light shielding member 6 and the optical path of the image light L may be about 1 μm or more, and may be more than twice the maximum wavelength of the visible light wavelength (about 0.83 μm). The upper limit of the shortest distance between the light shielding member 6 and the optical path of the image light L is not particularly limited, but in order to suppress the increase in size of the aerial image display device 1A, it may be about 10 mm, about 3 mm, or about 1 mm.

[0081] Next, an aerial image display device according to another embodiment of the present disclosure will be described. Figure 4 A sectional view showing the main structure of an aerial image display device according to another embodiment of the present disclosure. An aerial image display device 1B of this embodiment includes a focusing member as compared to the aerial image display device 1 of the above embodiment, and the other structures are the same, so the description of the same structures is omitted.

[0082] The aerial image display device 1B includes a display device 2, a first concave mirror 3, a second concave mirror 5, and a focusing member 7. The first concave mirror 3 and the second concave mirror 5 have the same structures as those of the aerial image display device 1, respectively.

[0083] The light focusing member 7 is located between the display device 2 and the first concave mirror 3. The light focusing member 7 may be located outside the display device 2 at a position close to the display surface 2a, or may be provided inside the display device 2. The light focusing member 7 substantially parallelizes the image light L emitted from the display surface 2a, and propagates the image light L toward the first concave mirror 3.

[0084] The focusing member 7 may be, for example, a plano-convex lens, a biconvex lens, a Fresnel lens, or the like. When the focusing member 7 is a Fresnel lens, the focusing member 7 can be made thinner, and as a result, the aerial image display device 1B can be miniaturized. In addition, in the case where the display device 2 is a liquid crystal display device including a backlight and a liquid crystal panel, the focusing member 7 may also be located between the backlight and the liquid crystal panel. An anti-reflection coating may also be formed on the surface of the focusing member 7 that is opposite to the display surface 2a (i.e., the incident surface of the image light L). In addition, the Fresnel lens is a lens that is thinned by dividing a conventional convex lens into concentric circular areas, and has a sawtooth-like cross-sectional shape. The greater the number of concentric circular areas, i.e., the number of divisions, the thinner it can be.

[0085] The focusing member 7 can suppress a portion of the image light L emitted from the display surface 2a from propagating directly toward the second concave mirror 5. Therefore, the aerial image display device 1 can suppress the image light L emitted from the display surface 2a from reaching the second concave mirror 5 without passing through the first concave mirror 3 and being reflected by the second concave mirror 5 in an undesired direction and position. As a result, it is possible to suppress the occurrence of double images that are visually recognized by the eyes of the user 10, or the visual recognition of virtual images by the eyes of the user 10, and the reduction in the visual recognizability of the aerial image R can be reduced. In addition, by not including the shading member 6, the aerial image display device 1B can increase the freedom of spatial configuration of the display device 2 relative to the reflective optical system 8 composed of the first concave mirror 3 and the second concave mirror 5. As a result, the aerial image display device 1B can be miniaturized.

[0086] The light focusing member 7 may also be a structure that can move in the optical axis direction of the image light L. In this case, the parallelism of the image light L of the light focusing member 7 can be adjusted. The moving device of the light focusing member 7 may also include a stepping motor, a linear motor, an ultrasonic motor, a guide rail, a slider, etc. The moving device of the light focusing member 7 may also be a structure that includes an adjustment member such as a knob or a screw, and the light focusing member 7 is moved by adjusting the adjustment member manually.

[0087] like Figure 4 As shown, the aerial image display device 1B may also be a structure in which the inclination angle θ2 of the imaginary plane P including the display surface 2a relative to the second concave mirror 5 is greater than the inclination angle θ1 of the imaginary plane P relative to the first concave mirror 3. The inclination angles θ1 and θ2 are defined in the same manner as above. In the aerial image display device 1B, by making the inclination angle θ2 greater than the inclination angle θ1, most of the image light L emitted from the display surface 2a is directed toward the first concave mirror 3, so that the image light L is easily incident on the first concave mirror 3 and is difficult to be directly incident on the second concave mirror 5. As a result, the generation of ghosting and virtual images can be suppressed, and the reduction in the visual recognizability of the aerial image R can be effectively reduced. In addition, in Figure 4 In the case of a structure of, θ1 may be approximately 25° to 55°, and θ2 may be approximately 70° to 110°, but are not limited to these ranges.

[0088] The aerial image display device 1B may include a light shielding member 6. In this case, it is possible to further suppress a portion of the image light L emitted from the display surface 2a from being directly propagated toward the second concave mirror 5. Therefore, it is possible to further suppress the occurrence of a double image that is visually recognized by the eyes of the user 10, or a virtual image that is visually recognized by the eyes of the user 10, and it is possible to further reduce the reduction in the visibility of the aerial image R.

[0089] The aerial image display device 1B may have a structure in which the curvature Sa1 is greater than the curvature Sa2 when the curvature of the reflection surface 3a of the first concave mirror 3 is set to Sa1 and the curvature of the reflection surface 5a of the second concave mirror 5 is set to Sa2. The curvatures Sa1 and Sa2 are defined in the same manner as described above. Since the curvature Sa1 is relatively large, the first concave mirror 3 that reflects the image light L emitted from the display device 2 in a direction different from the direction toward the display device 2 can be arranged close to the display device 2. As a result, the space occupied by the display device 2 and the reflection optical system 8 (the first concave mirror 3 and the second concave mirror 5) can be reduced, and the aerial image display device 1B can be miniaturized. Furthermore, by miniaturizing the aerial image display device 1B, the optical path length of the image light L between the display surface 2a of the display device 2 and the reflection surface 5a of the second concave mirror 5 can be shortened, so that the loss of the image light L caused by undesired scattering, interference, etc. can be suppressed. As a result, the display quality of the aerial image display device 1B can be improved.

[0090] In the direction parallel to the imaginary imaging plane of the aerial image R ( Figure 4 When the second concave mirror 5 is observed from the back side of the second concave mirror 5 (in the up and down direction in the image), the second concave mirror 5 may also overlap with the display device 2 and the first concave mirror 3. In this case, the space occupied by the display device 2 and the reflective optical system 8 can be reduced and reduced, so the aerial image display device 1B can be miniaturized. As a result, since the optical path length of the image light L inside the aerial image display device 1B can be shortened, the loss of the image light L caused by unexpected scattering, interference, etc. can be suppressed. Furthermore, the display quality of the aerial image display device 1B can be improved.

[0091] The aerial image display devices 1, 1A, 1B do not require touch operation of buttons, etc., so that the aerial image can be operated without touch, and thus, as a result, can be used in various product fields as follows. For example, a communication device for conversation / communication with aerial images, a medical consultation device for a doctor to consult a patient through aerial images, a navigation device / driving control device for a vehicle such as a car, an order receiving device / cash register device for a store, etc., an operation panel for a building / elevator, etc., a learning device for giving or receiving lessons with aerial images, an office device for business contact / instruction with aerial images, a game machine for playing games with aerial images, a projection device for projecting images onto the ground / wall surface, etc. in an amusement park / game center, etc., a simulator device for performing simulation experiments with aerial images in a university / medical institution, etc., a large display for displaying prices, etc. in a market / stock exchange, etc., an image viewing device for viewing images of aerial images, etc.

[0092] The present disclosure can be implemented by the following structures (1) to (13).

[0093] (1) An aerial image display device, comprising:

[0094] A display device having a display surface;

[0095] a first concave mirror, which reflects the image light emitted from the display surface in a direction different from the direction toward the display device;

[0096] a second concave mirror, which reflects the image light reflected by the first concave mirror in a direction different from the direction toward the first concave mirror, and forms an image as a real aerial image; and

[0097] The light shielding member is located between the display device and the second concave mirror and is not located in an optical path of the image light that reaches the aerial image from the display surface via the first concave mirror and the second concave mirror.

[0098] (2) The aerial image display device according to (1) above, wherein an inclination angle of the imaginary plane of the display surface relative to the second concave mirror is greater than an inclination angle of the imaginary plane relative to the first concave mirror.

[0099] (3) In the aerial image display device according to (1) or (2), the light shielding member can electrically adjust light transmittance.

[0100] (4) In the aerial image display device according to any one of (1) to (3), the shortest distance between the light shielding member and the optical path of the image light is longer than a wavelength of visible light.

[0101] (5) An aerial image display device comprising:

[0102] A display device having a display surface;

[0103] a first concave mirror, which reflects the image light emitted from the display surface in a direction different from the direction toward the display device;

[0104] a convex mirror, which reflects the image light reflected by the first concave mirror in a direction different from a direction toward the first concave mirror;

[0105] a second concave mirror, which reflects the image light reflected by the convex mirror in a direction different from the direction toward the convex mirror, and forms an image as a real aerial image; and

[0106] a light shielding member located between the display device and the second concave mirror and not located in an optical path of the image light that reaches the aerial image from the display surface via the first concave mirror, the convex mirror, and the second concave mirror,

[0107] The convex mirror is located between the light shielding member and the second concave mirror.

[0108] (6) The aerial image display device according to (5) above, wherein an inclination angle of the imaginary plane of the display surface relative to the second concave mirror is greater than an inclination angle of the imaginary plane relative to the first concave mirror.

[0109] (7) In the aerial image display device according to (5) or (6), the light shielding member can electrically adjust light transmittance.

[0110] (8) In the aerial image display device according to any one of (5) to (7), the shortest distance between the light shielding member and the optical path of the image light is longer than the wavelength of visible light.

[0111] (9) An aerial image display device comprising:

[0112] A display device having a display surface;

[0113] a first concave mirror, which reflects the image light emitted from the display surface in a direction different from the direction toward the display device;

[0114] a second concave mirror, which reflects the image light reflected by the first concave mirror in a direction different from the direction toward the first concave mirror, and forms an image as a real aerial image; and

[0115] A light-collecting member is located between the display device and the first concave mirror, and collimates the image light emitted from the display surface.

[0116] (10) The aerial image display device according to (9) above, wherein an inclination angle of the imaginary plane of the display surface relative to the second concave mirror is greater than an inclination angle of the imaginary plane relative to the first concave mirror.

[0117] (11) In the aerial image display device described in (9) or (10) above, the light focusing member is movable in the optical axis direction of the image light.

[0118] (12) In the aerial image display device according to any one of (9) to (11), the light focusing member is a Fresnel lens.

[0119] (13) The aerial image display device according to any one of (9) to (12), wherein the display device is a liquid crystal display device including a backlight and a liquid crystal panel.

[0120] The light focusing member is located between the backlight and the liquid crystal panel.

[0121] Since the aerial image display device of the present disclosure includes a light shielding member or a light focusing member, it is possible to suppress the occurrence of ghosting and virtual images due to a part of the image light being directed to an unintended direction or location. As a result, it is possible to reduce the reduction in visibility of the aerial image.

[0122] The embodiments of the present disclosure are described in detail above, but the present disclosure is not limited to the above embodiments, and various changes and improvements can be made without departing from the main purpose of the present disclosure. For example, the aerial image display device 1, 1A may also include a focusing member 7. In this case, the reduction in the visual recognition of the aerial image R can be more effectively reduced.

[0123] -Description of Reference Numerals-

[0124] 1.1A, 1B Aerial image display device

[0125] 2 Display device

[0126] 2a Display surface

[0127] 3 The first concave mirror

[0128] 3a Reflective surface

[0129] 4 Convex mirror

[0130] 4a Reflective surface

[0131] 5 Second concave mirror

[0132] 5a Reflective surface

[0133] 6 Shading member

[0134] 6a Shading surface

[0135] 7 Focusing components

[0136] 8.8A Reflective optical system

[0137] 9 Control device

[0138] 10 User

[0139] R Aerial image.

Claims

1. An aerial image display device, comprising: A display device having a display surface; a first concave mirror, which reflects the image light emitted from the display surface in a direction different from the direction toward the display device; a second concave mirror, reflecting the image light reflected by the first concave mirror in a direction different from the direction toward the first concave mirror, forming an image as a real aerial image; as well as The light shielding member is located between the display device and the second concave mirror and is not located in an optical path of the image light that reaches the aerial image from the display surface via the first concave mirror and the second concave mirror.

2. The aerial image display device according to claim 1, wherein: An inclination angle of an imaginary plane including the display surface relative to the second concave mirror is greater than an inclination angle of the imaginary plane relative to the first concave mirror.

3. The aerial image display device according to claim 1 or 2, wherein: The light shielding member can electrically adjust light transmittance.

4. The aerial image display device according to any one of claims 1 to 3, wherein: The shortest distance between the light shielding member and an optical path of the image light is longer than a wavelength of visible light.

5. An aerial image display device, comprising: A display device having a display surface; a first concave mirror, which reflects the image light emitted from the display surface in a direction different from the direction toward the display device; a convex mirror, which reflects the image light reflected by the first concave mirror in a direction different from a direction toward the first concave mirror; a second concave mirror, reflecting the image light reflected by the convex mirror in a direction different from the direction toward the convex mirror, forming an aerial image of a real image; as well as a light shielding member located between the display device and the second concave mirror and not located in an optical path of the image light that reaches the aerial image from the display surface via the first concave mirror, the convex mirror, and the second concave mirror, The convex mirror is located between the light shielding member and the second concave mirror.

6. The aerial image display device according to claim 5, wherein: An inclination angle of an imaginary plane including the display surface relative to the second concave mirror is greater than an inclination angle of the imaginary plane relative to the first concave mirror.

7. The aerial image display device according to claim 5 or 6, wherein: The light shielding member can electrically adjust light transmittance.

8. The aerial image display device according to any one of claims 5 to 7, wherein: The shortest distance between the light shielding member and an optical path of the image light is longer than a wavelength of visible light.

9. An aerial image display device, comprising: A display device having a display surface; a first concave mirror, which reflects the image light emitted from the display surface in a direction different from the direction toward the display device; a second concave mirror, reflecting the image light reflected by the first concave mirror in a direction different from the direction toward the first concave mirror, forming an image as a real aerial image; as well as A light-collecting member is located between the display device and the first concave mirror, and collimates the image light emitted from the display surface.

10. The aerial image display device according to claim 9, wherein: An inclination angle of an imaginary plane including the display surface relative to the second concave mirror is greater than an inclination angle of the imaginary plane relative to the first concave mirror.

11. The aerial image display device according to claim 9 or 10, wherein: The light focusing member is movable in the optical axis direction of the image light.

12. The aerial image display device according to any one of claims 9 to 11, wherein: The light focusing member is a Fresnel lens.

13. The aerial image display device according to any one of claims 9 to 12, wherein: The display device is a liquid crystal display device having a backlight and a liquid crystal panel. The Fresnel lens is located between the backlight and the liquid crystal panel.

Images