Aerial image display device

Abstract

The aerial image display device includes: a display unit; an optical system for imaging the image light emitted from the display unit as a real aerial image; a translucent screen between the aerial image and the optical system; and an image projection device that emits projected image light toward the translucent screen from a direction different from an optical axis direction of the image light between the aerial image and the optical system. The translucent screen displays a projected image by transmitting image light and diffusing projected image light.

Description

Technical Field

[0001] The present disclosure relates to an aerial image display device that simultaneously displays an aerial image and a projection image. Background Art

[0002] For example, Patent Document 1 describes an aerial image display device of the prior art. The aerial image display device of the prior art comprises: a display panel, wherein a display area for displaying a two-dimensional image is alternately switched between a transparent state in which the two-dimensional image is not displayed and a non-transparent state in which the two-dimensional image is displayed; and a stereoscopic projection device, which is arranged on the back side of the display panel and projects a stereoscopic projection image at a position overlapping with the display area of ​​the display panel when viewed from the front side. The aerial image display device is configured to display the stereoscopic projection image by making at least the area of ​​the display panel overlapping with the stereoscopic projection image transparent, and alternately switching between the non-transparent state in which the two-dimensional image is displayed and the transparent state in which the stereoscopic projection image is displayed in a short time, so that the two-dimensional image and the stereoscopic projection image can be visually recognized at the same time.

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-45424 Summary of the invention

[0006] The aerial image display device disclosed in the present invention is configured as follows, comprising: a first light emitting unit; an optical system for imaging the first light emitted from the first light emitting unit into a real aerial image; an optical component located between the aerial image and the optical system; and a second light emitting unit for emitting second light toward the optical component from a direction between the aerial image and the optical system that is different from the direction of the optical axis of the first light, wherein the transmittance of the first light of the optical component is higher than the transmittance of the second light. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The objects, features and advantages of the present disclosure will become more apparent from the following detailed description and the accompanying drawings.

[0008] Figure 1 It is a cross-sectional view showing the structure of an aerial image display device according to one embodiment of the present disclosure.

[0009] Figure 2A This is a flowchart for explaining the operation of the control unit of the aerial image display device according to one embodiment of the present disclosure.

[0010] Figure 2B This is a flowchart for explaining the operation of the control unit of the aerial image display device according to another embodiment of the present disclosure.

[0011] Figure 3It is a perspective view showing an example of a display state of the aerial image display device according to one embodiment of the present disclosure.

[0012] Figure 4 This is a partially enlarged cross-sectional view for explaining the function of the light-transmitting screen in the aerial image display device according to one embodiment of the present disclosure. DETAILED DESCRIPTION

[0013] In the prior art described in the above-mentioned patent document 1, when displaying a stereoscopic projection image, the display area at least overlaps the area of ​​the stereoscopic projection image and is set to a transparent state, so when the stereoscopic projection image is displayed, internal structures such as a reflector behind the display area can sometimes be seen from the transparent area. If the internal structure is seen from the outside, the internal structure enters the visual field of the observer's eyes, making it difficult to visually recognize the stereoscopic projection image. In addition, sometimes the focus of the observer's eyes deviates from the stereoscopic projection image, resulting in a decrease in the display quality of the stereoscopic projection image.

[0014] In addition, in the prior art of Patent Document 1, when the display device displaying the two-dimensional image is a liquid crystal display device with a backlight, for example, in the two-dimensional projection image displayed in black, a gray backlight image (also called a postcard image) with reduced blackness is likely to appear, and a visible postcard effect is generated. In this case, the postcard image enters the field of vision of the observer's eyes, making it difficult to visually recognize the three-dimensional projection image. In addition, sometimes the contrast between the two-dimensional projection image and the three-dimensional projection image is reduced, and then the three-dimensional projection image becomes difficult to visually recognize, resulting in a reduction in the display quality of the three-dimensional projection image.

[0015] Therefore, conventionally, there has been a demand for an aerial image display device that can display an aerial image with excellent display quality while making internal structures invisible from the outside and reducing the influence of the postcard effect.

[0016] Hereinafter, embodiments of the aerial image display device disclosed herein will be described with reference to the drawings.

[0017] Figure 1 1 is a cross-sectional view showing the structure of an aerial image display device according to an embodiment of the present disclosure. The aerial image display device 1 according to the present embodiment includes a display unit 2 as a first light emitting unit. The first light emitting unit may be a single light source or a structure including a plurality of light sources. The first light emitting unit may be a display unit 2 that displays a full-color moving image or the like. In addition, it may be an indication device that indicates a direction or the like, an indication device that displays symbols, traffic signs or the like, a signal device that displays a traffic signal or the like, a warning device that displays a warning light, or the like.

[0018] The aerial image display device 1 includes an optical system 3 that images the image light B1, B2, B3, and B4 emitted from the display unit 2 as the first light into a real aerial image R. The first light may be monochromatic light (light of a single wavelength) or light including multiple colors (for example, red light, green light, and blue light as three primary colors). The optical system may be a reflective optical system including a reflector or a structure including a reflector and a focusing member (for example, a focusing lens such as a Fresnel lens). The optical system may also be a structure including a reflector and a holographic element.

[0019] The aerial image display device 1 includes: a translucent screen 4 as an optical member, located between the aerial image R and the optical system 3; and an image projection device 5, which emits a projection image light B5 toward the translucent screen 4 from a direction different from the optical axis direction of the image light B4 between the aerial image R and the optical system 3. The optical member may also include a light diffusion member, and the projection image light B5 as the second light is diffused by the light diffusion member to reflect the projection image on the translucent screen 4. In addition, "~" means "to", and the same applies to the following.

[0020] The transmittance of the image lights B1, B2, B3, and B4 of the optical component is higher than the transmittance of the projected image light B5. The transmittance of the optical component (total light transmittance: visible light transmittance) can also be about 10% to 95%, about 30% to 95%, or about 50% to 90%, but it is not limited to these ranges. The total light transmittance is expressed by the ratio (%) of the total transmitted light transmitted to the other side of the optical component relative to the incident light incident from one side of the optical component at an incident angle of 0°. The total light transmittance is measured, for example, by the method described in JIS K7361: 1997 (ISO1346-1: 1996). That is, an entrance opening and an exit opening are provided in a spherical integrating sphere with a hollow interior, an optical component is arranged at the entrance opening, and a light sensor is arranged at the exit opening, and the transmitted light of the transmitted optical component is measured using the light sensor. The entrance opening and the exit opening are located at mutually opposing positions of the integrating sphere.

[0021] The optical component may also be a liquid crystal shutter (LCW: LC window) using a polymer liquid crystal. In this case, by controlling the voltage applied to the liquid crystal shutter to an intermediate voltage other than the cutoff voltage (voltage for shielding light), the light transmittance and light diffusivity of the optical component can be controlled. As a result, an aerial image and a projected image projected on the optical component by the projection image light B5 can be displayed, and the brightness of the aerial image and the projected image can be controlled. The transmittance (total light transmittance: visible light transmittance) of the liquid crystal shutter may also be about 10% to 95%, about 30% to 95%, or about 50% to 90%, but is not limited to these ranges. The total light transmittance is expressed by the ratio (%) of the total transmitted light transmitted to the other side of the liquid crystal shutter to the incident light incident from one side of the liquid crystal shutter at an incident angle of 0°. The total light transmittance is measured, for example, by the method described in JIS K7361:1997 (ISO1346-1:1996). That is, a method of providing an entrance opening and an exit opening in a spherical integrating sphere with a hollow interior, disposing a liquid crystal shutter at the entrance opening and a light sensor at the exit opening, and measuring the transmitted light through the liquid crystal shutter using the light sensor. The entrance opening and the exit opening are located at mutually opposing positions of the integrating sphere.

[0022] The image projection device 5 as the second light emitting unit may be a single light source or a structure having multiple light sources. The projection image light B5 as the second light may be monochromatic light (light of a single wavelength) or light including multiple colors (for example, red light, green light, and blue light as three primary colors). The second light emitting unit may also be a display unit that displays full-color moving images, etc., and may also be an indicating device that indicates directions, etc., an identification device that displays marks, traffic signs, etc., a signal device that displays traffic signals, etc., a warning device that displays warning lights, etc.

[0023] The transmittance of the image lights B1, B2, B3, and B4 of the light-transmitting screen 4 is higher than the transmittance of the projection image light B5. The light-transmitting screen 4 transmits most of the image lights B1, B2, B3, and B4, and diffuses most of the projection image light B5 without transmitting it. As a result, the images of the image lights B1, B2, B3, and B4 are hardly displayed on the light-transmitting screen 4, but the projection image of the projection image light B5 is projected.

[0024] The translucent screen 4 may also be a structure having a translucent member (translucent film) including a light diffusion member such as light diffusion particles. In addition, the translucent screen 4 may also be a structure in which a translucent film is laminated on a translucent substrate (glass substrate, plastic substrate, etc.). The translucent film is rectangular in shape with a length of about 1000 mm to 1500 mm on one side when viewed from above, and has a thickness of about 10 μm to 1 mm (for example, about 100 μm). The transmittance (total light transmittance: visible light transmittance) of the translucent film (optical member) may also be about 10% to 95%, or about 30% to 95%, or about 50% to 90%, but is not limited to these ranges. The total light transmittance is expressed by the ratio (%) of the total transmitted light transmitted to the other side of the translucent film relative to the incident light incident from one side of the translucent film at an incident angle of 0°. The total light transmittance is measured, for example, by the method described in JIS K7361: 1997 (ISO1346-1: 1996). That is, an entrance opening and an exit opening are provided in a spherical integrating sphere that is hollow inside, a translucent film is arranged at the entrance opening, and a light sensor is arranged at the exit opening, and the light transmitted through the translucent film is measured using the light sensor. The entrance opening and the exit opening are located at mutually opposing positions of the integrating sphere. The total light transmittance of the translucent screen 4 can also be measured with the translucent film alone, or it can be measured in a state where the translucent film is bonded to a glass substrate (visible light transmittance is about 90%) or a plastic substrate (visible light transmittance is about 87% to 93%) and stacked. In addition, the transmittance of the translucent screen 4 can be adjusted by changing the number of stacking layers of the translucent film.

[0025] The haze (turbidity) of the optical component can also be about 3% to 98%, about 3% to 50%, or about 4% to 30%, but it is not limited to these ranges. The haze is expressed by the proportion (%) of the transmitted light that is incident from one surface side of the optical component and transmitted to the other surface side and deviates from the optical axis of the incident light by more than 0.044 rad (2.5°) due to forward scattering. The haze is measured, for example, by the method described in JIS K 7136: 2000 (ISO 14782: 1999). That is, an optical component is arranged at the entrance opening of the above-mentioned integrating sphere, and a light sensor is arranged around the exit opening, and the light sensor is used to measure the transmitted light that is transmitted through the optical component and transmitted from the optical axis of the incident light. In the case where the optical component is a translucent screen or a liquid crystal shutter, the haze can also be measured by the same method as the above method.

[0026] The light-transmitting screen 4 of the aerial image display device 1 is a structure in which the transmittance of the first light (image light B1, B2, B3, B4) is higher than the transmittance of the second light (projection image light B5). As a result, the light-transmitting screen 4 transmits most of the first light and diffuses most of the second light to display the projected image. The aerial image display device 1 has the following effects through the above-mentioned structure. Since the aerial image display device 1 displays the aerial image R in a state where the projection image S has been displayed on the light-transmitting screen 4, it is difficult for the observer to visually recognize the internal structure such as the third reflector 33. As a result, it is possible to prevent the internal structure from entering the field of vision of the observer's eyes 13 and prevent the observer from visually recognizing the aerial image R. In addition, since the aerial image R is displayed in a state where the projection image S is displayed behind the aerial image R, the influence of the postcard effect can be reduced by the projection image S, and the postcard image can be prevented from being visually recognized by the observer. Therefore, the aerial image R can be displayed with excellent display quality.

[0027] The aerial image display device 1 may be a structure having the following components: an illuminance detection unit 6 that detects the illuminance of ambient light; and a control unit 7 that performs feedback control (hereinafter also referred to as "control") on the display unit 2 in a direction in which the brightness of the aerial image R increases according to an increase in the detection value of the illuminance detection unit 6, and performs feedback control on the display unit 2 in a direction in which the brightness of the aerial image R decreases according to a decrease in the detection value. That is, the control unit 7 performs positive feedback control on the brightness of the aerial image R with respect to the detection value of the illuminance detection unit 6. In the case of this structure, when the illuminance of the ambient light becomes higher, that is, when the environment becomes brighter, the brightness of the aerial image R is increased. In addition, when the illuminance of the ambient light becomes lower, that is, when the environment becomes darker, the brightness of the aerial image R is reduced. Thus, it is possible to suppress the difficulty of the observer in visually recognizing the aerial image R due to the influence of the ambient light. The illuminance detection unit 6 may also be a commercially available illuminometer for cameras, etc. In order to detect the illuminance of the ambient light, the illuminance detection unit 6 may be provided at a location that reflects the influence of solar radiation on the aerial image display device 1, for example, on a top plate 9e described later.

[0028] The aerial image display device 1 further includes, for example, a hollow rectangular parallelepiped housing 8. The housing 8 includes: four side walls 9a to 9d constituting a quadrangular prism; a top plate 9e connected vertically to the edges of the side walls 9a to 9d so as to block an opening on one side of the quadrangular prism formed by the side walls 9a to 9d; and a bottom plate 9f connected vertically to the edges of the side walls 9a to 9d so as to block an opening on the other side of the quadrangular prism formed by the side walls 9a to 9d.

[0029] A first through hole 10 is formed on the top plate 9e, and a transparent first light-transmitting plate 11 is embedded and fixed in the first through hole 10. The first light-transmitting plate 11 transmits the projection image light B5 projected from the image projection device 5 to the light-transmitting screen 4, and prevents foreign matter such as rainwater and dust from intruding into the housing 8. Such a housing 8 is made of a light-shielding and highly rigid material such as metal or synthetic resin. The display unit 2 and the optical system 3 are accommodated in the housing 8, and external light is cut off, and foreign matter is prevented from intruding into the light path of the display unit 2 and the optical system 3.

[0030] A second through hole 12 is formed in one side wall 9a disposed on the front side, i.e., the observer side, of the four side walls 9a to 9d, and the light-transmitting screen 4 is inserted and fixed in the second through hole 12. The light-transmitting screen 4 displays the projection image S from the image projection device 5 and blocks the infiltration of foreign matter such as dust into the frame 8.

[0031] As described above, the control unit 7 performs feedback control on the display unit 2 in a direction in which the brightness of the aerial image R increases according to the increase in the detection value of the ambient light detected by the illumination detection unit 6, and performs feedback control on the display unit 2 in a direction in which the brightness of the aerial image R decreases according to the decrease in the detection value. As a method for controlling the brightness of the aerial image R, for example, the brightness value of the image signal of the display unit 2 can be changed to a brightness value pre-set according to the detection value of the ambient light. Specifically, in a storage unit of a driving element such as an IC, LSI, etc. possessed by a driving unit such as a driving circuit of the display unit 2, or a storage unit such as a storage circuit (memory, register) possessed by the driving unit, the illumination data of the ambient light and the brightness data of the image signal corresponding to the illumination data are pre-stored. The illumination data of the ambient light can also be data obtained by converting a current value or a voltage value corresponding to the detection value of the illumination into a binary signal such as a digital signal. Similarly, the brightness data of the image signal can also be data obtained by converting a current value or a voltage value corresponding to the brightness value into a binary signal such as a digital signal. Then, when the illumination detection unit 6 detects the illumination of the ambient light, the control unit 7 refers to the illumination data and brightness data in the storage unit, and determines the illumination data and brightness data corresponding to the detection value based on the detected value of the illumination of the ambient light. The control unit 7 uses the determined brightness data to control the brightness value of the display unit 2. The control unit 7 may also be provided in the driving unit of the display unit 2, or may be provided as Figure 1 The display is shown outside the display unit 2.

[0032] As a specific method for the control unit 7 to control the brightness of the aerial image R based on the detection value of the illuminance of the ambient light detected by the illuminance detection unit 6, there are the following methods. As a first method, a method of controlling the contrast between the brightness of the aerial image and the brightness of the ambient light, the so-called ambient contrast (also referred to as environmental contrast) ACR, is within a given range in consideration of the illuminance (brightness) of the ambient light. ACR is represented by the formula (ADSon+ABL) / (ADSoff+ABL). ADSon is the brightness of the aerial image R when the display unit 2 (for example, a liquid crystal display device) is displayed in full screen white, and ADSoff is the brightness of the aerial image R when the liquid crystal display device as the display unit 2 is displayed in full screen black. ABL is represented by (Ab×R1)+(Ab×T2×R2), where Ab is the brightness of the ambient light, R1 is the reflectivity of the translucent screen 4, and (Ab×R1) represents the intensity of the ambient light reflected by the translucent screen 4 and entering the observer's eye 13. T is the transmittance of the translucent screen 4, R2 is the reflectance of the third reflector 33, and (Ab×T2×R2) represents the intensity of ambient light that transmits the translucent screen 4, is reflected by the third reflector 33, transmits the translucent screen 4 again and enters the observer's eye 13.

[0033] When ACR is 3, the aerial image R can be recognized, when ACR is 5, the aerial image R can be appropriately visually recognized, and when ACR is 10 or more, the aerial image R can be easily visually recognized. Therefore, ADSon can be controlled so that ACR is 3 or more. For example, if it is a liquid crystal display device, the brightness of the backlight (input power value or input current value) can also be controlled. In addition, ADSon can be controlled so that ACR is 5 or more, and ADSon can be controlled so that ACR is 10 or more. The upper limit of ACR can be 20 or 15. In addition, it is not limited to these ACR values.

[0034] As a second method, there is a method of detecting the brightness of the aerial image R using a light sensor or the like, and changing the brightness value of the backlight 2a of the liquid crystal display device as the display unit 2 according to the detected value of the illumination of the ambient light. The illumination of the ambient light in the room is about 100 to 1200 lux, and the brightness of the aerial image R is about 200 to 500 lux. The brightness of the displayed image of the liquid crystal display device is about 400 to 1200 lux, and the light transmittance of the liquid crystal panel is about 5%. The light transmittance of the optical system 3 is about 80%. The brightness of the backlight 2a is about 8000 to 24000 lux. For example, when the illumination of the ambient light increases by 100 lux and the brightness of the aerial image R increases by 100 lux accordingly, the brightness of the backlight 2a increases by about 2500 lux (100×(1 / 0.8)×(1 / 0.05)). The light transmittance of the optical system 3 (about 80%) includes the transmittance of the translucent screen 4, and may be 80%×(transmittance of the translucent screen 4). The transmittance of the translucent screen 4 may be about 10% to 95%, but is not limited to this range. When the increase in the illumination of the ambient light is set to ΔL1 and the corresponding increase in the brightness of the aerial image R is set to ΔL2, it may be set to ΔL2 / ΔL1=0.1 to 5, ΔL2 / ΔL1=0.3 to 3, or ΔL2 / ΔL1=0.5 to 1.5, but is not limited to these ranges.

[0035] The illumination detection unit 6 detects the illumination of the ambient light and the control unit 7 controls the brightness value of the display unit 2 at a period of 30 Hz or more, or at a period of 60 Hz or more. This can suppress changes in the brightness value of the display unit 2 that the observer visually recognizes, such as flickering of the aerial image R.

[0036] The display unit 2 includes a backlight 2a and a transmissive display device 2b. The transmissive display device 2b may be a transmissive liquid crystal display device (LCD) that transmits light from the backlight 2a and displays an image based on the alignment state of liquid crystals included in each of a plurality of pixels.

[0037] The liquid crystal display device may include a known liquid crystal panel. As a known liquid crystal panel, various liquid crystal panels such as IPS (In-Plane Switching), FFS (Fringe Field Switching), VA (Vertical Alignment), and ECB (Electrically Controlled Birefringence) may be used. The liquid crystal panel may be configured to include a first polarizing plate, a color filter substrate, a liquid crystal layer, an array substrate, and a second polarizing plate. The first polarizing plate may be located on the display surface side of the display device.

[0038] The control unit 7 may be configured to increase the brightness of the projected image S in accordance with an increase in the brightness of the aerial image R, and to decrease the brightness of the projected image S in accordance with a decrease in the brightness of the aerial image R, and to perform feedback control on the image projection device 5 so that the intensity (brightness) of the postcard image light of the backlight 2a becomes less than a given value relative to the intensity (brightness) of the projected image light B5. The postcard image light is generated, for example, by a gray backlight image whose blackness is reduced in the projected image S displayed in black, a so-called postcard effect in which a postcard image appears visible.

[0039] The given value of the intensity of the postcard image light relative to the intensity (in candela or lux) of the projection image light B5 (wherein the intensity of the projection image light B5 may also be the average intensity of the entire image) may be, in terms of the SN ratio, less than -20 dB (1 / 10), or further less than -30 dB (1 / 31.6), less than -35 dB (1 / 56.2), or less than -40 dB (1 / 100). For example, the intensity of the projection image light B5 may be controlled by comparing the detection value (also referred to as the first detection value) obtained by the optical sensor detecting the intensity of the projection image light B5 with the detection value (also referred to as the second detection value) obtained by the optical sensor detecting the intensity of the postcard image light, or the intensity of the backlight 2a may be controlled so that (the second detection value) / (the first detection value) is, for example, less than -20 dB (1 / 10). In order to control the intensity of the projection image light B5, the input power value of the image projection device 5 may also be controlled. In order to control the intensity of the backlight 2a, the input power value of the backlight 2a may also be controlled.

[0040] The control unit 7 may also be configured to include more than one processor. The processor may include a general-purpose processor configured to read a specific program and execute a specific function, and a dedicated processor specifically used for a specific process for displaying the aerial image R together with the projection image S. As a dedicated processor, an IC (Application Specific Integrated Circuit: ASIC) for a specific purpose may also be included. The processor may include a programmable logic device (Programmable Logic Device: PLD). The PLD may include an FPGA (Field-Programmable Gate Array). The control unit 7 may be any of a SoC (System-on-a-Chip) and a SiP (System In a Package) configured to cooperate with one or more processors.

[0041] The optical system 3 includes: a first reflector 31 that reflects the image light B1 emitted from the display unit 2 and generates image light B2 as reflected light; a second reflector 32 that reflects the image light B2 reflected by the first reflector 31 and generates image light B3 as reflected light; and a third reflector 33 that reflects the image light B3 reflected by the second reflector 32 and generates image light B4 as reflected light. The first reflector 31 and the third reflector 33 may also be formed by concave mirrors, and the second reflector 32 may also be formed by convex mirrors. The reflecting surfaces of the concave mirror and the convex mirror are not limited to spherical surfaces, and may also be aspherical surfaces. These first reflector 31, the second reflector 32, and the third reflector 33 are not limited to the aforementioned convex mirrors and concave mirrors, and free-form mirrors may also be used.

[0042] The translucent screen 4 transmits the image light B4 forming the aerial image R and diffuses the projection image light B5 of the projection image S, thereby displaying the projection image S on the display surface of the translucent screen 4 and displaying the aerial image R of the real image in the space in front of the translucent screen 4 .

[0043] The light-transmitting screen 4 may also be a structure including a light-transmitting resin film or a light-transmitting resin layer with a thickness of 0.1 μm to 20 mm including a light-diffusing member. The resin material of the light-transmitting resin film or the light-transmitting resin layer may also be acrylic resin, silicone resin, polycarbonate resin, epoxy resin, polyethylene terephthalate (PET) resin, etc. The light-diffusing member may also be, for example, light-diffusing particles. The material of the light-diffusing member may also be titanium oxide, silicon oxide, aluminum oxide, glass, etc. In order to project the projection image light B5 from the image projection device 5 on the light-transmitting screen 4, it is necessary to scatter the projection image light B5 to form an image of the projection image S, but if scattering occurs, it is easy to lose transparency. In order to take into account these opposite characteristics, nano-dispersion technology is used to set the average particle size of the light-diffusing particles to the nanometer level and optimize the content and dispersibility. There are geometric scattering, Mie scattering, and Rayleigh scattering for light scattering, but the light-transmitting screen 4 uses Mie scattering with excellent color reproducibility. The average particle size of the light-diffusing particles is adjusted so that the intensity and light distribution balance of the scattered light are optimal. The average particle size of the light diffusion particles may also be about 10 nm to about 500 nm, but is not limited to this range. The content of the light diffusion particles may also be about 3 volume % to about 30 volume %, but is not limited to this range. As the light-transmitting resin film for the light-transmitting screen 4, for example, the trade name "KALEIDO SCREEN (registered trademark)" manufactured by ENEOS Corporation may also be used.

[0044] Figure 4It is a partially enlarged cross-sectional view for explaining the function of the translucent screen 4. The translucent screen 4 transmits the image light B4 and diffuses the projected image light B5, thereby displaying the projected image S. That is, the translucent screen 4 is located at a position where the thickness of the projected image light B5 in the optical axis direction is thicker than the thickness of the image light B4 in the optical axis direction. As a result, the probability of image light B4 being scattered by the light diffusion particles 4p becomes smaller, so most of it is transmitted through the translucent screen 4, and the probability of projected image light B5 being scattered by the light diffusion particles 4p becomes larger, so most of it is scattered by the translucent screen 4 to form the projected image S. Figure 4 In the case of , the image light B4 is incident on the surface of the light-transmitting screen 4 approximately perpendicularly, and passes through the thinnest portion. The projected image light B5 is incident on the surface of the light-transmitting screen 4 obliquely, and is incident on the thickened portion, and is mostly scattered.

[0045] The angle (intersection angle) formed by the optical axis direction of the image light B4 and the optical axis direction of the projection image light B5 may be approximately 10° to 60°, or approximately 20° to 45°, but is not limited to these ranges.

[0046] The light-transmitting screen 4 may also be a structure in which a light-transmitting member is stacked on a light-transmitting substrate. The light-transmitting substrate may also be a glass substrate, a plastic substrate, etc. The light-transmitting member may also be a light-transmitting resin film, a light-transmitting resin layer, etc. The resin material of the light-transmitting resin film and the light-transmitting resin layer may also be an acrylic resin, a silicone resin, a polycarbonate resin, an epoxy resin, a polyethylene terephthalate (PET) resin, etc. The light-transmitting resin layer may also be a coating layer formed by applying an uncured resin material to a light-transmitting substrate and curing it by heating and / or ultraviolet irradiation. In this case, the strength of the light-transmitting screen 4 increases. In addition, since it is easy to adjust the thickness of the light-transmitting member, it is easy to adjust the diffusion property of the light-transmitting screen 4, that is, it is easy to adjust the imaging property of the projected image S and the transmittance of the image light B4.

[0047] The light-transmitting member may also be a structure in which the light-diffusing member is uniformly dispersed throughout or partially throughout the light-transmitting member. When the light-diffusing member is uniformly dispersed throughout the light-transmitting member, the projection image S can be projected throughout the light-transmitting screen 4, and the internal structure and the postcard image can be effectively suppressed from being visually recognized from the outside. When the light-diffusing member is uniformly dispersed partially throughout the light-transmitting member, the projection image S can be projected at a portion of the light-transmitting screen 4 where the internal structure and the postcard image can be easily visually recognized from the outside.

[0048] For example, Figure 3As shown, it is also possible to configure that the display unit 2 as the first light emitting unit is a display device such as a liquid crystal display device, and the second light emitting unit is a projection device 5 that displays an image of a projection image S on a light-transmitting screen 4, and the size of the projection image S is larger than the size of the aerial image R. In this case, the projection image S is easily visually recognized as a background image of the aerial image R, and the aerial image R is easy to appear to protrude further toward the observer relative to the observer's eyes 13. As a result, the aerial image R is easily visually recognized as a stereoscopic image (three-dimensional image). The size (e.g., area) of the projection image S may also exceed 1 times the size (e.g., area) of the aerial image R and be less than or equal to about 10 times, but is not limited to this range.

[0049] In addition, the brightness of the aerial image R may be higher than that of the projected image S. In this case, the projected image S is easily visually recognized as a background image of the aerial image R, and the aerial image R is likely to appear to protrude further toward the observer relative to the observer's eye 13. The brightness of the aerial image R may be more than 1 times the brightness of the projected image S and may be less than or equal to about 10 times, but is not limited to this range.

[0050] In addition, the grayscale of the aerial image R may be higher than the grayscale of the projected image S, that is, the aerial image R is a high grayscale image and the projected image S is a low grayscale image. In this case, it is easy to see that the aerial image R protrudes further toward the observer relative to the observer's eye 13. The grayscale of the aerial image R may be more than 1 times and less than about 20 times the grayscale of the projected image S, but is not limited to this range.

[0051] In addition, the resolution of the aerial image R may be higher than the resolution of the projected image S. In this case, it is easy to see that the aerial image R protrudes further toward the observer relative to the observer's eye 13. The resolution of the image can be represented by the modulation transfer function (MTF). MTF can be used as a resolution index for comparing the resolution of an image. MTF is a function of the spatial frequency ν (1 / mm) and is maximum when ν=0. MTF can be normalized to a maximum value of 1. In this case, it can be said that the closer the value of MTF is to 1, the higher the resolution. In addition, by setting the area obtained by integrating the MTF on the spatial frequency axis as the performance index of the image, the resolution of the image can be evaluated with high precision. The resolution of the aerial image R may also exceed 1 times the resolution of the projected image S and be less than about 5 times, but is not limited to this range.

[0052] Furthermore, when the aerial image R and the projected image S are moving images, the aerial image R may move faster than the projected image S. In this case, it is easy to see that the aerial image R is closer to the observer than the projected image S with respect to the observer's eye 13. The moving speed of the aerial image R may exceed 1 times and be about 10 times or less than the moving speed of the projected image S, but is not limited to this range.

[0053] In addition, it is also possible to configure such that a detection device (e.g., an imaging device such as a camera) for detecting the sight direction of the observer's eye 13 is provided, and a control unit for controlling variables is provided, and when the sight line of the observer's eye 13 is directed toward the aerial image R by the detection device, the control unit for controlling variables further increases at least one of the brightness, grayscale, resolution, and moving speed of the aerial image R. In this case, when the observer is looking at the aerial image R, the aerial image R can be made more eye-catching than the projected image S. As a result, the observer can easily see that the aerial image R is more prominent. The control unit for controlling variables may be included in the control unit 7, or may be provided separately from the control unit 7.

[0054] Figure 2A This is a flowchart for explaining the operation of the control unit of the aerial image display device of one embodiment of the present disclosure. The processing operation of the control unit 7 of the aerial image display device 1 described above is explained. In step S0, the power of the aerial image display device 1 is turned on to start the control unit 7. Next, the process moves to step S1, and the illuminance detection unit 6 measures the illuminance of the ambient light around the aerial image display device 1 that displays the aerial image R and the projected image S, and outputs the resulting illuminance detection value to the control unit 7. Next, the process moves to step S2, and the control unit 7 receives the illuminance detection value of the ambient light detected by the illuminance detection unit 6, and determines the brightness value of the aerial image R corresponding to the illuminance of the ambient light.

[0055] Next, in step S3, the brightness value of the backlight 2a of the display unit 2 is changed by the above-mentioned first method or second method.

[0056] When the brightness of the aerial image R increases due to the change in brightness value (step S4) or when the brightness of the aerial image R decreases (step S5), the control unit 7 terminates the feedback control of the brightness of the aerial image R in the next step S6. That is, the control of changing the input power value (input current value) of the backlight 2a of the liquid crystal display device is terminated.

[0057] Figure 2B This is a flowchart for explaining the operation of the control unit of the aerial image display device according to another embodiment of the present disclosure. Steps S1 to S5 are Figure 2A, so their description is omitted. In step S6, when the brightness of the aerial image R increases, the brightness of the projected image S is increased. In addition, in step S7, when the brightness of the aerial image R decreases, the brightness of the projected image S is decreased. For example, when the brightness of the aerial image R is increased or decreased by 100 lux, the brightness of the projected image S (wherein the brightness of the projected image S may also be the average brightness) may also be increased or decreased by the same value (100 lux). Alternatively, the aerial image R and the projected image S may be controlled to have a given contrast, such as a given value (e.g., 3.2 (10dB)) within the range of 1 (0dB) ≤ (brightness of the aerial image R) / (brightness of the projected image S) ≤ 10 (20dB).

[0058] Next, in step S8, the intensity of the postcard image light and the intensity of the projection image light are compared. The comparison of the intensity of the postcard image light and the intensity of the projection image light can be implemented by detecting the postcard image light and the projection image light respectively using a light sensor or the like. Alternatively, data on the intensity of the postcard image light corresponding to the input power value (input current value) of the backlight 2a of the liquid crystal display device may be stored in advance as a data table in a storage unit (memory), and the intensity of the postcard image light may be determined by referring to the data table.

[0059] Next, in step 9, the image projection device 5 is controlled so that (intensity of postcard image light) / (intensity of projection image light) is less than a given value. For example, as described above, the given value is controlled to be -20 dB (1 / 10), -30 dB (1 / 31.6), or -35 dB (1 / 56.2) in terms of SN ratio. After determining the brightness value of the projection image S, the control unit 7 feeds back the determined brightness value to the image projection device 5, and ends the brightness value rewriting process.

[0060] Finally, when the rewriting process of the brightness value of the projection image S is completed, if the aerial image R is continuously displayed, that is, the displayed image data is continuously displayed, the process returns to step S1 again. That is, based on the illumination detection value of the illumination detection unit 6, the brightness of the aerial image R and the brightness of the projection image S are repeatedly rewritten until the input of the display image data is completed. If the aerial image R is not continuously displayed, the process transfers to step S11, and the display of the aerial image R and the display of the projection image S are terminated.

[0061] Figure 3 1 is a stereoscopic diagram showing an example of a display state of an aerial image display device according to an embodiment of the present disclosure. In the aerial image display device 1 of this embodiment, a projection image S is displayed on a light-transmitting screen 4 by an image projection device 5, and an aerial image R is displayed on the near side of the light-transmitting screen 4, i.e., the observer side, by a display unit 2. Figure 3 In the example, the aerial image R is the earth, and the background projection image S is the universe. An image of the earth floating in the universe is displayed. By displaying the projection image S, it is possible to suppress the observer from seeing the internal structure of the housing 8 as in the above-mentioned prior art. In addition, since the aerial image R and the projection image S behind it are displayed at the same time, the depth of the projection image S relative to the aerial image R is emphasized by the motion parallax between the aerial image R and the projection image S when the line of sight moves. As a result, the stereoscopic effect and three-dimensional recognition as if the aerial image R is floating in the space on the observer's side are improved.

[0062] Then, if Figure 2A As shown, the brightness of the aerial image R can be controlled according to the illumination of the ambient light. This can prevent the aerial image R from being difficult to observe due to the ambient light.

[0063] Furthermore, when the brightness of the aerial image R increases, the brightness of the postcard image also increases, and when the brightness of the aerial image R decreases, the brightness of the postcard image also decreases. Figure 2B As shown, the brightness of the rear projection image S can also be feedback-controlled so that the postcard image is suppressed from being visually recognized by the observer in the outer space. In this case, the influence of the postcard image light is reduced, and the aerial image R is easily visually recognized by the observer's eyes 13. As a result, the display quality of the aerial image R is improved.

[0064] The aerial image display device of the present disclosure can use a self-luminous display device such as a liquid crystal display device (Light Emitting Diode: LED) and an organic EL display device as a display unit. In addition, the aerial image display device according to the present disclosure enables the aerial image to be operated without touching, and as a result, the aerial image display device can be used in the following various product fields, but the present disclosure is not limited thereto. For example, a communication device for conversation / communication accompanied by an aerial image, a medical consultation device for a doctor to consult a patient through an aerial image, a navigation device / operation control device for a vehicle such as a car, an order receiving device / cash register device for a store, an operation panel for a building / elevator, a learning device for teaching or receiving a lesson accompanied by an aerial image, an office device for business contact / instruction accompanied by an aerial image, a game machine for playing games accompanied by an aerial image, a projection device for projecting an image onto a ground / wall surface, etc. in an amusement park / game center, etc., a simulator device for conducting simulation experiments, etc. through an aerial image in a university / medical institution, etc., a large display for displaying prices, etc. in a market / stock exchange, etc., an image appreciation device for appreciating an image of an aerial image, etc.

[0065] According to the aerial image display device disclosed in the present invention, since the aerial image is displayed in a state where a projection image formed by a second light is displayed on an optical component, it is difficult for an observer to visually recognize the internal structure, and it is possible to suppress a situation where it is difficult for an observer to visually recognize the aerial image. As a result, it is possible to suppress a reduction in the display quality of the aerial image. In addition, since the aerial image is displayed in a state where a projection image is displayed behind the aerial image, it is possible to reduce the influence of the postcard effect through the projection image, and suppress the postcard image from being visually recognized by the observer. As a result, the aerial image can be displayed with excellent display quality.

[0066] The present disclosure can be implemented in the following configurations (1) to (14).

[0067] (1) An aerial image display device comprising:

[0068] a first light emitting portion;

[0069] an optical system for imaging the first light emitted from the first light emitting portion into a real aerial image;

[0070] an optical member located between the aerial image and the optical system; and

[0071] a second light emitting unit configured to emit second light toward the optical member from a direction different from a direction of an optical axis of the first light between the aerial image and the optical system;

[0072] The optical member has a higher transmittance of the first light than a transmittance of the second light.

[0073] (2) In the aerial image display device according to (1) above, the optical member includes a light-transmitting member including a light diffusion member.

[0074] (3) In the aerial image display device according to (2) above, the optical member is a structure in which the light-transmitting member is stacked on a light-transmitting base material.

[0075] (4) In the aerial image display device according to (3) above, the light diffusing member of the light-transmitting member is uniformly dispersed.

[0076] (5) In the aerial image display device according to (4) above, the light diffusing member of the light-transmitting member is locally evenly dispersed.

[0077] (6) In the aerial image display device according to any one of (2) to (5) above, the optical member is located at a position where a thickness of the second light in the optical axis direction is greater than a thickness of the first light in the optical axis direction.

[0078] (7) The aerial image display device according to any one of (1) to (6) above,

[0079] The first light emitting portion is a display device,

[0080] The second light emitting unit is an image projection device that displays a projection image on the optical member.

[0081] The size of the projected image is larger than the size of the aerial image.

[0082] (8) The aerial image display device according to (7) above, wherein the brightness of the aerial image is higher than the brightness of the projected image.

[0083] (9) The aerial image display device according to (7) above, wherein the grayscale of the aerial image is higher than the grayscale of the projected image.

[0084] (10) In the aerial image display device according to (7) above, a resolution of the aerial image is higher than a resolution of the projected image.

[0085] (11) The aerial image display device according to (7) above, wherein, when the aerial image and the projected image are moving images, a moving speed of the aerial image is faster than a moving speed of the projected image.

[0086] (12) The aerial image display device according to any one of (1) to (11) above,

[0087] have:

[0088] an illumination detection unit for detecting the illumination of ambient light; and

[0089] The control unit performs feedback control on the first light emitting unit in a direction to increase the brightness of the aerial image according to an increase in the detection value of the illuminance detecting unit, and performs feedback control on the first light emitting unit in a direction to decrease the brightness of the aerial image according to a decrease in the detection value.

[0090] (13) The aerial image display device according to (12) above,

[0091] The first light emitting unit is a transmissive display device having a backlight.

[0092] The second light emitting unit is an image projection device that displays a projection image on the optical member.

[0093] The control unit performs feedback control on the image projection device so that the brightness of the projected image increases according to the increase of the brightness of the aerial image, and the brightness of the projected image decreases according to the decrease of the brightness of the aerial image, and the intensity of the postcard image light of the backlight becomes less than a given value relative to the intensity of the projected image light.

[0094] (14) In the aerial image display device according to (13) above, the transmissive display device is a liquid crystal display device.

[0095] The embodiments of the present disclosure are described in detail above. In addition, the present disclosure is not limited to the above embodiments, and various changes and improvements can be made without departing from the scope of the present disclosure. Of course, all or part of the above embodiments can be appropriately combined within the scope of non-contradiction.

[0096] -Description of Reference Numerals-

[0097] 1 Aerial image display device

[0098] 2 Display

[0099] 2a Backlight

[0100] 2b Transmissive display device

[0101] 3 Optical system

[0102] 4 Translucent screen

[0103] 5 Image Projection Device

[0104] 6 Illumination detection unit

[0105] 7 Control Unit

[0106] 8 Housing

[0107] 9a~9d Side wall

[0108] 9e Top Plate

[0109] 9f Base Plate

[0110] 10 First through hole

[0111] 11. First light-transmitting plate

[0112] 12 Second through hole

[0113] 31 First Reflector

[0114] 32 Second reflector

[0115] 33 Third reflector

[0116] B1, B2, B3, B4 Image light

[0117] B5 Projection image light

[0118] R Aerial Image

[0119] S Projected image.

Claims

1. An aerial image display device, a first light emitting portion; an optical system for imaging the first light emitted from the first light emitting portion into a real aerial image; an optical member located between the aerial image and the optical system; and a second light emitting unit configured to emit second light toward the optical member from a direction different from a direction of an optical axis of the first light between the aerial image and the optical system; The optical member has a higher transmittance of the first light than a transmittance of the second light.

2. The aerial image display device according to claim 1, wherein: The optical member includes a light-transmitting member including a light diffusion member.

3. The aerial image display device according to claim 2, wherein: The optical member has a structure in which the light-transmitting member is stacked on a light-transmitting base material.

4. The aerial image display device according to claim 3, wherein: The light diffusing member of the light-transmitting member is uniformly dispersed.

5. The aerial image display device according to claim 4, wherein: The light diffusion member of the light-transmitting member is locally uniformly dispersed.

6. The aerial image display device according to any one of claims 2 to 5, wherein: The optical member is located at a position where a thickness of the second light in the optical axis direction is thicker than a thickness of the first light in the optical axis direction.

7. The aerial image display device according to claim 1, wherein: The first light emitting portion is a display device, The second light emitting unit is an image projection device that displays a projection image on the optical member. The size of the projected image is larger than the size of the aerial image.

8. The aerial image display device according to claim 7, wherein: The brightness of the aerial image is higher than the brightness of the projected image.

9. The aerial image display device according to claim 7, wherein: The grayscale of the aerial image is higher than the grayscale of the projected image.

10. The aerial image display device according to claim 7, wherein: The resolution of the aerial image is higher than the resolution of the projected image.

11. The aerial image display device according to claim 7, wherein: When the aerial image and the projected image are moving images, the moving speed of the aerial image is faster than the moving speed of the projected image.

12. The aerial image display device according to claim 1, wherein: have: an illumination detection unit for detecting the illumination of ambient light; and The control unit performs feedback control on the first light emitting unit in a direction to increase the brightness of the aerial image according to an increase in the detection value of the illuminance detecting unit, and performs feedback control on the first light emitting unit in a direction to decrease the brightness of the aerial image according to a decrease in the detection value.

13. The aerial image display device according to claim 12, wherein: The first light emitting unit is a transmissive display device having a backlight. The second light emitting unit is an image projection device that displays a projection image on the optical member. The control unit performs feedback control on the image projection device so that the brightness of the projected image increases according to the increase of the brightness of the aerial image, and the brightness of the projected image decreases according to the decrease of the brightness of the aerial image, and the intensity of the postcard image light of the backlight becomes less than a given value relative to the intensity of the projected image light.

14. The aerial image display device according to claim 13, wherein: The transmissive display device is a liquid crystal display device.

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