Display device and aerial image display device

Abstract

A display device according to the present disclosure comprises a display unit and when an image displayed by the display unit contains a high-temperature image section showing a high-temperature object having a temperature higher than a predetermined temperature, the display device displays the high-temperature image section using light including infrared light. Moreover, an aerial image display device according to the present disclosure includes: a display unit which includes a display surface; and a reflective optical system that reflects image light of an image displayed on the display surface to form an image as an aerial image of the real image. When an image contains a high-temperature image section showing a high-temperature object having a temperature higher than the predetermined temperature, the aerial image display device displays the high-temperature image section on the display surface using light including the infrared light. The aerial image display device is capable of displaying the high-temperature image section as a moving image.

Description

[Technical Field]

[0001] This disclosure relates to a display device and an aerial image display device. [Background technology]

[0002] Conventionally, an aerial image display device, such as the one described in Patent Document 1, is known. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-67707 [Overview of the project]

[0004] The display device of this disclosure comprises a display unit, If the image displayed by the display unit includes a high-temperature image section that shows a high-temperature object at a temperature higher than a predetermined temperature, the high-temperature image section is displayed using light including infrared light.

[0005] The aerial image display device disclosed herein includes a display unit having a display surface, The system includes a reflective optical system that reflects the image light of the image displayed on the display surface and forms an aerial image of the real image, If the image includes a high-temperature image portion that shows a high-temperature object at a temperature higher than a predetermined temperature, the high-temperature image portion is displayed on the display surface using light including infrared light. [Brief explanation of the drawing]

[0006] The purpose, features, and advantages of this disclosure will become clearer from the detailed description and drawings below. [Figure 1A] This figure shows the configuration of an aerial image display device according to one embodiment of the present disclosure, and is a side view and block view of the main part. [Figure 1B] This figure shows the configuration of an aerial image display device of another embodiment of the present disclosure, and is a side view and block view of the main part. [Figure 2A]Figure 1A is a cross-sectional view showing an example of the display unit of an aerial image display device. [Figure 2B] This is a plan view showing an example of the arrangement of multiple visible light emitting units and multiple infrared light emitting units in the display unit of Figure 2A. [Figure 3] This is a diagram showing an example of an image to be displayed on the display unit, and is a front view of the image. [Figure 4A] This is a cross-sectional view showing another example of the display unit of the aerial image display device in Figure 1A. [Figure 4B] This is a plan view showing an example of the arrangement of multiple visible light emitting units and multiple infrared light emitting units in the display unit of Figure 4A. [Figure 4C] This is a plan view showing another example of the arrangement of multiple visible light emitting units and multiple infrared light emitting units in the display unit of Figure 4A. [Figure 5] Figure 1A is a diagram illustrating the definition of the curvature of the first concave mirror in the reflective optical system of the aerial image display device, and is a cross-sectional view of the first concave mirror. [Figure 6] This is a plan view showing another example of the arrangement of multiple visible light emitting units and multiple infrared light emitting units in the display unit of Figure 2A. [Figure 7] This is a plan view showing another example of the arrangement of multiple visible light emitting units and multiple infrared light emitting units in the display unit of Figure 4A. [Figure 8] This figure shows the configuration of an aerial image display device of another embodiment of the present disclosure, and is a side view and block view of the main part. [Figure 9] This figure shows the configuration of an aerial image display device of another embodiment of the present disclosure, and is a side view and block view of the main part. [Figure 10] Figure 9 is a diagram illustrating the operation and effects of the aerial image display device, and is a side view of the user's hand and its surroundings. [Figure 11] This figure shows the configuration of an aerial image display device of another embodiment of the present disclosure, and is a side view and block view of the main part. [Modes for carrying out the invention]

[0007] Conventionally, various aerial image display devices have been proposed that form an aerial image by imaging image light emitted from a display device. Patent Document 1 discloses an aerial image display device that includes a display device that emits infrared light.

[0008] There is a need to provide users with a new visual experience. The conventional display device and aerial image display device described in Patent Document 1 did not provide users with a new visual experience using infrared light.

[0009] Embodiments of this disclosure will be described below with reference to the drawings. The following drawings show the main components of the aerial image display device according to the embodiment. The aerial image display device according to the embodiment may include well-known components such as drive circuits, circuit boards, wiring conductors, and cases, which are not shown. The following drawings are schematic, and the dimensional ratios shown in the drawings do not necessarily correspond to those in reality. Also, in some drawings, a Cartesian coordinate system XYZ is defined for convenience.

[0010] Figs. 1A and 1B are diagrams showing the configurations of the aerial image display devices according to two embodiments of the present disclosure. Fig. 2A is a cross-sectional view showing an example of the display unit of the aerial image display device of Fig. 1A. Fig. 2B is a plan view showing an example of the arrangement of a plurality of visible light emitting units and a plurality of infrared light emitting units in the display unit of Fig. 2A. Fig. 3 is a front view showing an example of an image displayed on the display unit. Fig. 4A is a cross-sectional view showing another example of the display unit of the aerial image display device of Fig. 1A. Fig. 4B is a plan view showing an example of the arrangement of a plurality of visible light emitting units and a plurality of infrared light emitting units in the display unit of Fig. 4A. Fig. 4C is a plan view showing another example of the arrangement of a plurality of visible light emitting units and a plurality of infrared light emitting units in the display unit of Fig. 4A. Fig. 5 is a cross-sectional view of the first concave mirror explaining the definition of the curvature of the first concave mirror in the reflection optical system of the aerial image display device of Fig. 1A. Fig. 6 is a plan view showing another example of the arrangement of a plurality of visible light emitting units and a plurality of infrared light emitting units in the display unit of Fig. 2A. Fig. 7 is a plan view showing another example of the arrangement of a plurality of visible light emitting units and a plurality of infrared light emitting units in the display unit of Fig. 4A. In Figs. 1A and 1B, the aerial image is shown with hatching. Fig. 2A shows a cross-section cut along the cutting plane line IIA-IIA of Fig. 2B. Fig. 4A shows a cross-section cut along the cutting plane line IVA-IVA of Fig. 4B. In Figs. 2B, 4B, 4C, 6, and 7, the infrared light emitting units (infrared light emitting elements) are shown with hatching. Also, in Figs. 2B, 4B, 4C, 6, and 7, only the visible light emitting units and the infrared light emitting units arranged on the substrate are shown.

[0011] The display device of the present disclosure includes a display unit, and when the image displayed by the display unit includes a high-temperature image portion that reflects a high-temperature object at a temperature higher than a predetermined temperature, it is configured to display the high-temperature image portion using light including infrared light. For example, as shown in FIG. 3, when the display device has a display surface 2a and the image 4 displayed by the display surface 2a includes a high-temperature image portion 43 that reflects a high-temperature object at a temperature higher than a predetermined temperature, the high-temperature image portion 43 is displayed using light including infrared light. With the above configuration, the following effects are achieved. When the image 4 includes the high-temperature image portion 43, since the high-temperature image portion 43 of the image 4 is displayed by light (visible light) including infrared light, the user (also referred to as the viewer) can perceive the high-temperature image portion 43 of the visible light through vision and temperature sensation (for example, skin sensation, hereinafter also referred to as "thermal sensation"). As a result, a new video experience with thermal sensation can be provided to the user.

[0012] The display device may include a display unit 2, a housing that houses the display unit 2, a support member such as a pedestal that supports the housing, and the like. The display unit 2 may be a transmissive display unit, and in that case, it may be a liquid crystal display unit including a backlight and a liquid crystal panel. The backlight may be a direct-lit backlight having a plurality of light-emitting units two-dimensionally arranged on the back side of the liquid crystal panel. For example, the plurality of light-emitting units may include a plurality of visible light-emitting units and a plurality of infrared light-emitting units. The backlight has a substrate, and the plurality of visible light-emitting units and the plurality of infrared light-emitting units may be alternately arranged in a matrix on one surface (also referred to as the light-emitting surface) of the substrate. The visible light-emitting unit and the infrared light-emitting unit may be composed of self-luminous elements such as, for example, light-emitting diodes (LEDs) and organic light-emitting diodes (OLEDs).

[0013] The display unit 2 of the display device is not limited to a transmissive display unit 2, but may be a self-emissive display unit 2 including a plurality of self-emissive elements. The self-emissive elements may be LEDs, OLEDs, etc. The self-emissive display unit 2 includes a plurality of pixels. Each of the plurality of pixels may include a visible light emitting unit and an infrared light emitting unit. The self-emissive display unit 2 has a substrate, and the plurality of visible light emitting units and the plurality of infrared light emitting units may be arranged alternately in a matrix on the light-emitting surface of the substrate.

[0014] If the image 4 displayed by the display unit 2 includes a high-temperature image unit 43 that shows a high-temperature object at a temperature higher than a predetermined temperature (e.g., room temperature), then, if it is a liquid crystal display unit, the infrared light emission unit corresponding to the high-temperature image unit 43 in the backlight will be illuminated. If it is a self-emissive display unit 2, the infrared light emission unit corresponding to the high-temperature image unit 43 will be illuminated. The emission intensity of the infrared light emission unit may be controlled according to the assumed temperature of the high-temperature image unit 43. The emission intensity of the infrared light emission unit may be controlled, for example, by controlling the current input to the infrared light emission unit and the applied voltage by an emission control unit connected to the display unit 2 or an emission control unit provided in the display unit 2. If the high-temperature image unit 43 is a person, animal, character, etc., the emission intensity of the infrared light emission unit may be controlled so that the user perceives a warmth equivalent to their body temperature (approximately 35°C to 37°C). If the high-temperature image unit 43 is a heating element, for example, hot water (approximately 38°C to 42°C), the emission intensity of the infrared light emission unit may be controlled so that the user perceives a warmth equivalent to that of hot water. If the high-temperature image unit 43 is a heat source, for example a flame, the emission intensity of the infrared light emission unit may be controlled so that the user perceives a warmth (approximately 40°C to 50°C) similar to the warmth felt when holding a hand over a flame. If the high-temperature image unit 43 is a heat source, for example the sun, the emission intensity of the infrared light emission unit may be controlled so that the user perceives a warmth (approximately 30°C to 50°C) equivalent to solar heat.

[0015] The display device may distinguish between the high-temperature image section 43 and the non-high-temperature image section in the image 4 displayed on the display unit 2 as follows. The display device may be equipped with a light emission control unit and configured to store image data for each frame in the light emission control unit, and may be configured to store the image data of the high-temperature image section 43 (also called high-temperature image data) in a way that allows for distinction. For example, start flag data, start tag data, etc., indicating that it is the start section may be added to the beginning (start section) of the high-temperature image data, and end flag data, end tag data, etc., indicating that it is the end section may be added to the end (termination section) of the high-temperature image data. The process of adding start flag data, start tag data, etc., to the high-temperature image data, and the process of adding end flag data, end tag data, etc., may be performed manually. Alternatively, the process of adding start flag data, start tag data, etc., to the high-temperature image data, and the process of adding end flag data, end tag data, etc., may be based on capturing the image 4 displayed on the display unit 2 with an imaging device such as a camera, analyzing the captured image (captured image) with analysis program software, and identifying the high-temperature image section 43 in the captured image. The analysis program software may include artificial intelligence (AI) program software that performs image recognition by analyzing captured images and detecting and extracting specific patterns. The AI ​​program software may also perform image recognition by directly analyzing image data and detecting and extracting specific patterns.

[0016] Display devices can be applied to various electronic devices. These electronic devices include car navigation systems, ship navigation systems, aircraft navigation systems, instrument indicators and instrument panels for vehicles such as automobiles, smartphones, mobile phones, tablet devices, personal digital assistants (PDAs), video cameras, digital still cameras, electronic organizers, e-books, electronic dictionaries, personal computers, photocopiers, game terminals, televisions, product tags, price tags, industrial programmable display devices, car audio systems, digital audio players, fax machines, printers, automated teller machines (ATMs), vending machines, medical display devices, digital display watches, smartwatches, information display devices installed in stations and airports, digital signage for advertising, and head-mounted displays (HMDs).

[0017] As shown in Figure 1A, the aerial image display device 1 of this embodiment comprises a display unit (hereinafter also referred to as the display device) 2 and a reflective optical system 3.

[0018] The display device 2 has a display surface 2a and displays an image 4, which propagates as image light L towards the reflective optical system 3 (first concave mirror 31), on the display surface 2a. The display device 2 is capable of displaying an image 4 (an example is shown in Figure 3) composed of a visible light image including infrared light. The display device 2 emits image light L from the display surface 2a. The image light L may include at least one of visible light L1 and infrared light L2. Therefore, in some cases the image light L may consist only of visible light L1, and in other cases the image light L may consist only of infrared light L2.

[0019] The reflective optical system 3 reflects the image light L of the image 4 displayed on the display surface 2a and forms an image of the real image in the air R. As a result, the user 5 can perceive the air image R formed by the image of the image light L. If the image light L consists only of visible light L1, the user 5 can perceive the visible light air image R1 formed by the image of the visible light L1 visually. If the image light L includes both visible light L1 and infrared light L2, the user 5 can perceive the visible light air image R1 formed by the image of the visible light L1 visually and perceive the temperature of the infrared light air image R2 formed by the image of the infrared light L2 through senses (e.g., skin sensation). The reflective optical system 3 is composed of reflective optical elements such as a concave mirror and a convex mirror.

[0020] The display device 2 may be a transmissive display device 2 as shown in Figure 2A. The transmissive display device 2 may be a liquid crystal display device including a backlight 21 and a liquid crystal panel 22.

[0021] The backlight 21 may be a direct-lit backlight having a plurality of light-emitting units arranged two-dimensionally on the back side (i.e., the light incident surface) of the liquid crystal panel 22. The plurality of light-emitting units include a plurality of visible light-emitting units 21a and a plurality of infrared light-emitting units 21b. As shown in Figures 2A and 2B, the backlight 21 has a substrate 23, and the plurality of visible light-emitting units 21a and the plurality of infrared light-emitting units 21b may be arranged alternately in a matrix on the first surface 23a of the substrate 23. The visible light-emitting units 21a and infrared light-emitting units 21b may be composed of self-emissive elements such as light-emitting diodes (LEDs) and organic light-emitting diodes (OLEDs). The substrate 23 may be a glass substrate, a plastic substrate, a metal substrate, a ceramic substrate, etc., and may be a composite substrate formed by laminating a plurality of these types.

[0022] The visible light emitting section 21a may emit white light. In that case, the visible light emitting section 21a may include a red LED that emits red light, a green LED that emits green light, and a blue LED that emits blue light. The visible light emitting section 21a may also include a white LED that emits white light. The white LED may include an ultraviolet LED that emits ultraviolet light and a phosphor that converts the ultraviolet light emitted from the ultraviolet LED into white light. The white LED may include a blue LED that emits blue light and a phosphor that converts the blue light emitted from the blue LED into white light.

[0023] The infrared light emitting section 21b may be an infrared LED that emits infrared light. The infrared LED may be a near-infrared LED that emits near-infrared light or infrared light with a wavelength of approximately 0.78 μm to 2.5 μm. Note that "~" means "or," and the same applies hereinafter.

[0024] The liquid crystal panel 22 may be composed of a first polarizer, a color filter substrate, a liquid crystal layer, an array substrate, and a second polarizer, as is well known. The liquid crystal panel 22 includes a plurality of pixels. The pixels include sub-pixels for red emission, sub-pixels for green emission, and sub-pixels for blue emission. The pixels may also include sub-pixels for infrared emission. Since infrared light has a higher transmittance to the liquid crystal panel 22 than visible light, pixels do not need to include sub-pixels for infrared emission. The sub-pixels for red emission convert white light emitted from the visible light emission unit 21a into red light (red-colored light) by the red filter unit of the color filter substrate and control the amount of red light transmitted. The amount of red light transmitted may be controlled by controlling the light intensity of the white LED corresponding to the sub-pixel for red emission. Alternatively, the sub-pixels for red emission may utilize the red light emitted by the red LED in the visible light emission unit 21a corresponding to the sub-pixel. In this case, the amount of red light transmitted may be controlled by controlling the light intensity of the red LED. The above sub-pixel configuration can also be applied to sub-pixels for green emission and sub-pixels for blue emission. The sub-pixels for red emission, green emission, and blue emission may, to some extent, shield the infrared light emitted from the infrared light emission unit 21b.

[0025] If a pixel is equipped with a sub-pixel for infrared emission, the sub-pixel for infrared emission may utilize infrared light emitted by an infrared LED, which serves as an infrared light emission unit 21b, corresponding to the sub-pixel. The amount of infrared light transmitted through the sub-pixel for infrared emission may be controlled by controlling the light intensity of the infrared LED.

[0026] If a pixel does not have sub-pixels for infrared emission, the infrared light emitted by an infrared light LED or the like, which serves as the infrared light emission unit 21b, may be configured to transmit at least one of the sub-pixels for red emission, green emission, and blue emission. The amount of infrared light transmitted through the pixel may be controlled by controlling the light intensity of the infrared light LED or the like.

[0027] The display device 2, having the above configuration, can display a visible light image including infrared light on the display surface 2a in response to an image signal input from an external source. The display device 2 may also have a local dimming function. That is, the display device 2 may individually control the intensity of the white light emitted by each of the multiple visible light emitting units 21a, and individually control the intensity of the infrared light emitted by each of the multiple infrared light emitting units 21b, in response to an image signal input from an external source. In this case, the contrast and color tone of the image 4 can be improved, and as a result, the contrast and color tone of the aerial image R can be improved. In addition, the power consumption of the display device 2 can be reduced.

[0028] Figure 2B shows an example where the number of visible light emitting units 21a and the number of infrared light emitting units 21b are the same, but the number of infrared light emitting units 21b may be less than the number of visible light emitting units 21a. Since infrared light emitted from the infrared light emitting units 21b is more easily transmitted through the liquid crystal panel 22 than visible light (white light) emitted from the visible light emitting units 21a, a sufficient intensity of infrared light L2 can be maintained even if the number of infrared light emitting units 21b is less than the number of visible light emitting units 21a.

[0029] The display device 2 is not limited to a transmissive display device 2, but may be a self-emissive display device 2 including a plurality of self-emissive elements. The self-emissive display device 2 includes a plurality of pixels 24 (shown in Figure 4A). Each of the plurality of pixels 24 includes a visible light emitting part 24a and an infrared light emitting part 24b. As shown in Figures 4A and 4B, the self-emissive display device 2 has a substrate 23, and the plurality of visible light emitting parts 24a and the plurality of infrared light emitting parts 24b may be arranged alternately in a matrix on the first surface 23a of the substrate 23.

[0030] As shown in Figure 4B, each of the multiple visible light emitting units 24a has a red light-emitting element 24aR that emits red light, a green light-emitting element 24aG that emits green light, and a blue light-emitting element 24aB that emits blue light. Each of the multiple infrared light emitting units 24b has an infrared light-emitting element 24bI that emits infrared light. The red light-emitting element 24aR, green light-emitting element 24aG, blue light-emitting element 24aB, and infrared light-emitting element 24bI may be composed of, for example, LEDs, OLEDs, etc. The red light-emitting element 24aR, green light-emitting element 24aG, blue light-emitting element 24aB, and infrared light-emitting element 24bI may be composed of micro-LEDs. When arranged on the first surface 23a, the micro-LED may have a rectangular planar shape with a side length of approximately 1 μm to 100 μm or approximately 3 μm to 10 μm. The infrared light-emitting element 24bI may be a near-infrared LED, infrared LED, near-infrared OLED, or infrared OLED that emits near-infrared or infrared light with a wavelength of approximately 0.78 μm to 2.5 μm.

[0031] The self-emissive display device 2 individually controls the emission intensity of multiple visible light emission units 24a (i.e., red light-emitting element 24aR, green light-emitting element 24aG, and blue light-emitting element 24aB) and the emission intensity of multiple infrared light emission units 24b in response to an image signal input from an external source. As a result, the self-emissive display device 2 can display an image 4 composed of a visible light image and an infrared light image on the display surface 2a. Although the infrared light image cannot be directly perceived by human vision, the infrared light image portion and its surroundings in the aerial image R can be perceived by human touch. Therefore, the infrared light image can also be called an infrared light temperature-sensitive portion.

[0032] The red light-emitting element 24aR, green light-emitting element 24aG, blue light-emitting element 24aB, and infrared light-emitting element 24bI of each pixel of the self-emissive display device 2 may be arranged in the row direction (left-right direction in Figure 4B) of the display device 2, as shown in Figure 4B. The red light-emitting element 24aR, green light-emitting element 24aG, blue light-emitting element 24aB, and infrared light-emitting element 24bI of each pixel may be arranged in a 2x2 matrix, as shown in Figure 4C.

[0033] As shown in Figure 1A, the aerial image display device 1 includes a light emission control unit 6. The light emission control unit 6 controls the image 4 displayed on the display surface 2a based on an image signal input from an external source. The image signal includes a visible light image signal SV and an infrared light image signal SI. Based on the visible light image signal SV, the light emission control unit 6 displays a visible light image on the display surface 2a, and based on the infrared light image signal SI, it mixes infrared light into the display surface 2a. In other words, the light emission control unit 6 controls the display device 2 to mix infrared light into the visible light image.

[0034] The light emission control unit 6 may be configured to include one or more processors. The processors may include general-purpose processors configured to load specific programs and execute specific functions, and dedicated processors specialized for specific processing. The dedicated processors may include ASICs (Application Specific Integrated Circuits). The processors may include PLDs (Programmable Logic Devices). The PLDs may include FPGAs (Field-Programmable Gate Arrays). The light emission control unit 6 may also be a System-on-a-Chip (SoC) or System-in-a-Package (SiP) configured to have one or more processors working together.

[0035] The light emission control unit 6 may have functions to turn the display device 2 on and off, transmit image signals to the display device 2, and adjust the brightness, chromaticity, frame frequency, etc. of the image. Furthermore, if the display device 2 is equipped with a heat dissipation member or cooling member, the light emission control unit 6 may have a function to adjust the temperature of the heat dissipation member or cooling member.

[0036] If the image 4 displayed on the display surface 2a of the display device 2 includes a high-temperature image section 43 that shows a high-temperature object at a temperature higher than a predetermined temperature, the predetermined temperature may be defined as room temperature, as detailed below. In the following description of embodiments, the case in which the image 4 displayed on the display device 2 includes both a room-temperature image section 44 and a high-temperature image section 43 (an example is shown in Figure 3) will be mainly described. Note that the room-temperature image section 44 is a part that differs from the high-temperature image section 43 in the image 4.

[0037] The aerial image display device 1 may distinguish between the normal temperature image section 44 and the high temperature image section 43 in the image displayed on the display device 2 as follows. The light emission control unit 6 may be configured to store image data for each frame, and the image data of the high temperature image section 43 (also called high temperature image data) may be stored in a way that allows for distinction. For example, start flag data, start tag data, etc., indicating that it is the start of high temperature image data may be added to the beginning (start) of the high temperature image data, and end flag data, end tag data, etc., indicating that it is the end of high temperature image data may be added to the end (termination) of the high temperature image data. The process of adding start flag data, start tag data, etc., to the high temperature image data, and the process of adding end flag data, end tag data, etc., may be performed manually. Alternatively, the process of adding start flag data, start tag data, etc., to the high temperature image data, and the process of adding end flag data, end tag data, etc., may be performed based on capturing the image 4 displayed on the display device 2 with an imaging device such as a camera, analyzing the captured image (captured image) with analysis program software, and identifying the high temperature image section 43 in the captured image. The analysis program software may include artificial intelligence (AI) program software that performs image recognition by analyzing captured images and detecting and / or extracting specific patterns. The AI ​​program software may also perform image recognition by directly analyzing image data and detecting and / or extracting specific patterns.

[0038] Similarly, the image data of the ambient temperature image unit 44 (also called ambient temperature image data) may be made distinguishable and stored in the light emission control unit 6. For example, the beginning portion (start portion) of the ambient temperature image data may be added to indicate that it is the start portion of the ambient temperature image data, and the end portion (end portion) of the ambient temperature image data may be added to indicate that it is the end portion of the ambient temperature image data. The process of adding the start flag data, start tag data, etc. to the ambient temperature image data, and the process of adding the end flag data, end tag data, etc. may be performed in the same way as described above. The ambient temperature may be, for example, 15°C to 25°C, or 20°C. Alternatively, the aerial image display device 1 may include a temperature sensor 60 (shown in Figure 1B) that detects the ambient temperature, in which case the ambient temperature may be the ambient temperature detected by the temperature sensor 60. The ambient temperature may also be set by the user 5 to any temperature or any temperature range. This is because the temperature and temperature range that user 5 perceives as normal temperature tend to differ depending on their place of origin, place of residence, etc. In this case, user 5 may set normal temperature to any temperature or any temperature range within a range of approximately 0°C to 35°C, but is not limited to that range.

[0039] The aerial image display device 1 may have a storage unit 50 in the light emission control unit 6 that stores image data SD (shown in Figure 1B) and stores the high-temperature image data SDH (shown in Figure 1B) of the high-temperature image unit 43 in the image data SD in a way that distinguishes it from the normal-temperature image data SDL (shown in Figure 1B). The storage unit 50 may be composed of, for example, a line memory or a frame memory. The aerial image display device 1 may not have a storage unit 50 in the light emission control unit 6, but may have one separately. The storage unit 50 may output the image data SD, which includes the normal-temperature image data SDL and the high-temperature image data SDH, to the light emission control unit 6 as a visible light image signal SV. The storage unit 50 may also generate an infrared light image signal SI based on the high-temperature image data SDH and output the infrared light image signal SI to the light emission control unit 6.

[0040] When the aerial image display device 1 includes a high-temperature image section 43 that shows a high-temperature object at a temperature higher than room temperature (an example is shown in Figure 3), it displays the high-temperature image section 43 on the display surface 2a using light including infrared light. The light including infrared light may be visible light emitted from visible light emitting sections 21a and 24a and infrared light emitted from infrared light emitting sections 21b and 24b. The aerial image display device 1 displays the room-temperature image section 44 on the display surface 2a using visible light emitted from visible light emitting sections 21a and 24a. The display device 2 emits image light L from the display surface 2a, which includes visible light L1 representing the room-temperature image section 44 and visible light L1 and infrared light L2 representing the high-temperature image section 43. The image light L is reflected by the reflective optical system 3 and formed as an aerial image R. User 5 can visually perceive the visible light aerial image R1 formed by the imaging of visible light L1, and can also perceive the temperature of the infrared light aerial image R2 formed by the imaging of infrared light L2 through tactile sensation. The aerial image display device 1 can provide user 5 with a new and realistic visual experience using infrared light.

[0041] The light emission control unit 6 or the storage unit 50 may pre-store data of a specific image that can become the high-temperature image unit 43 (for example, an image of a person, an image of a fireplace, etc.) (for example, corresponding to the high-temperature image data SDH in Figure 1B) and its temperature in association with it. When the display device 2 displays the image 4, if the image data of the image 4 includes specific image data, the temperature detected by the temperature sensor 60 may be compared with the temperature pre-stored in association with the data of the specific image to distinguish, for example, between normal temperature image data SDL and high-temperature image data SDH. The temperature sensor 60 may be connected to at least one of the light emission control unit 6 and the storage unit 50.

[0042] The aerial image display device 1 may be capable of displaying a video of the high-temperature image unit 43. In this case, the user 5 can perceive the movement of the high-temperature image unit 43 (i.e., the high-temperature object) not only visually but also through tactile sensation. As shown in Figure 3, if the high-temperature object is a bonfire, the user 5 can perceive the flickering of the flames both visually and tactilely. Therefore, the aerial image display device 1 can provide the user 5 with a new visual experience using infrared light. The light emission control unit 6 can control the emission and non-emission of multiple visible light emission units 21a, 24a and multiple infrared light emission units 21b, 24b. The video display of the high-temperature image unit 43 is made possible by the light emission control unit 6 controlling the emission and non-emission of multiple visible light emission units 21a, 24a and multiple infrared light emission units 21b, 24b.

[0043] The high-temperature image unit 43 is composed of a visible light image 43a and an infrared light image 43b. As shown in Figure 3, the light emission control unit 6 may make the infrared light image 43b on the display surface 2a of the display device 2 large enough to encompass the visible light image 43a. This makes it possible to make the infrared light aerial image R2 on the virtual imaging surface 8 of the aerial image R large enough to encompass the visible light aerial image R1. As a result, the user 5 can perceive not only the heat of the high-temperature object itself, but also the radiant heat radiated from the high-temperature object to the surroundings or the conductive heat transferred by heat conduction. Therefore, a more realistic visual experience can be provided to the user 5.

[0044] The light emission control unit 6 may display the high-temperature image unit 43 on the display surface 2a such that the infrared light image 43b has a temperature gradient 43ba around the visible light image 43a. The temperature gradient 43ba is the portion where the intensity of infrared light decreases as it moves away from the center (centrosome) or edge of the visible light image 43a. This allows an infrared light aerial image R2 having a temperature gradient around the visible light aerial image R1 to be imaged on the virtual imaging surface 8. The temperature gradient portion of the infrared light aerial image R2 is the portion where the intensity of infrared light L2 decreases as it moves away from the center (centrosome) or edge of the visible light aerial image R1 perceived by the user 5, similar to the temperature gradient 43ba. This allows the user 5 to perceive not only the heat of the high-temperature object itself, but also the radiant heat radiated from the high-temperature object to the surroundings or the conductive heat transferred by heat conduction. Therefore, a more realistic visual experience can be provided to the user 5.

[0045] The temperature gradient of the temperature gradient section 43ba may be approximately 0.1°C / mm to 10°C / mm, or approximately 0.1°C / mm to 3°C / mm, but is not limited to this range.

[0046] The aerial image display device 1 may include a time lag control unit 7. When the high-temperature image unit 43 is displayed as a video, the time lag control unit 7 is configured to delay the movement of the infrared light image 43b in time relative to the movement of the visible light image 43a. This allows the user 5 to perceive the movement of the high-temperature object visually, and then perceive its movement through tactile sensation. Since heat transfer includes convection and conduction components, it may lag behind the movement of an object in time. This embodiment can represent the delay in heat transfer relative to the movement of an object. The time delay Δt between the movement of the infrared light image 43b and the movement of the visible light image 43a may be, for example, around 0.1 seconds to 1.0 second, but is not limited to this range. Δt may be determined based on, for example, the size (number of pixels) of the visible light image 43a, the distance between the user 5 and the virtual imaging surface 8, the thermal conductivity of air, the assumed temperature of the high-temperature object, etc. By delaying the movement of the infrared light image 43b relative to the movement of the visible light image 43a, a more realistic video experience can be provided to the user 5.

[0047] Furthermore, the time lag control unit 7 may gradually increase the infrared light intensity of the infrared light image 43b when the user 5 touches the high-temperature image section 43, which is displayed as a still image or a moving image, with their finger or the like. That is, from the moment the user 5 touches the high-temperature image section 43 with their finger or the like, while the user 5 is touching the high-temperature image section 43, the temperature of the high-temperature object that the user 5 feels through their skin sensation is gradually increased. Heat transfer includes a component of heat conduction, and since objects have heat capacity, there may be a time delay in the transfer of heat from the high-temperature object to the user 5's finger or the like, and the rise in the temperature of the user 5's finger or the like. By representing the temperature rise considering heat conduction and heat capacity, it is possible to represent the skin sensation that the user 5's finger or the like would feel when actually touching an object. For example, when the user 5's finger touches the high-temperature image section 43 displaying an animal, the user 5's finger may gradually become warmer. The temperature rise rate of the infrared light image 43b may be around 0.1℃ / sec to 1℃ / sec, but is not limited to this range. Furthermore, the temperature increase may be between 3°C and 10°C, but is not limited to this range.

[0048] The high-temperature object may be at least one of the following: a person, an animal, a character, and a heat-generating element. The character may be a popular character from animation, movies, etc., or a character created by the manufacturer of the aerial image display device 1. Alternatively, the character may be selected by the user 5 of the aerial image display device 1 from a plurality of samples displayed on a part of the display surface 2a. The heat-generating element may be, for example, a flame, bathwater and hot spring water, heated food and beverages, the sun, etc. The heat-generating element may be either a self-heating element such as the sun, or a heated element such as water.

[0049] If the aerial image R includes a high-temperature image section 43 that displays a high-temperature object at a temperature higher than a predetermined temperature (e.g., room temperature), a liquid crystal display device will emit light from the infrared light-emitting section 21b corresponding to the high-temperature image section 43 in the backlight. If it is a self-emissive display device, the infrared light-emitting section 24b corresponding to the high-temperature image section 43 will emit light. The emission intensity of the infrared light-emitting sections 21b and 24b may be controlled according to the assumed temperature of the high-temperature image section. The emission intensity of the infrared light-emitting sections 21b and 24b may be controlled, for example, by controlling the current input to the infrared light-emitting sections 21b and 24b and the applied voltage by an emission control unit 6 connected to the display device 2 or an emission control unit 6 provided in the display device 2. If the high-temperature image section 43 is a person, animal, character, etc., the emission intensity of the infrared light-emitting sections 21b and 24b may be controlled so that the user 5 perceives a warmth equivalent to their body temperature (approximately 35°C to 37°C). If the high-temperature image unit 43 is a heating element, for example, hot water (around 38°C to 42°C), the emission intensity of the infrared light emission units 21b and 24b may be controlled so that the user 5 perceives a temperature equivalent to that of hot water. If the high-temperature image unit 43 is a heating element, for example, a flame, the emission intensity of the infrared light emission units 21b and 24b may be controlled so that the user 5 perceives a temperature equivalent to that felt when holding a hand over a flame (around 40°C to 50°C). If the high-temperature image unit 43 is a heating element, for example, the sun, the emission intensity of the infrared light emission units 21b and 24b may be controlled so that the user 5 perceives a temperature equivalent to that of solar heat (around 30°C to 50°C).

[0050] When only the multiple visible light emitting units 24a are illuminated, only the visible light image can be displayed. When the multiple infrared light emitting units 24b are illuminated, only the infrared light image (heat-sensing unit) can be displayed, and the heat-sensing unit can be used as a heater during cold periods such as winter. By illuminating both the multiple visible light emitting units 24a and the multiple infrared light emitting units 24b, a portion of image 4 may be made into a visible light image, and the other portion of image 4 may be made into a heat-sensing unit. In this case, the visible light image may be made into a bright image with high brightness, such as the sun, to provide the user with a visual sense of warmth.

[0051] The reflective optical system 3 may include a first concave mirror 31, a convex mirror 32, and a second concave mirror 33, as shown in Figures 1A and 1B.

[0052] The first concave mirror 31 is located on the optical path of the image light L emitted from the display device 2. The first concave mirror 31 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. The convex mirror 32 is located on the optical path of the image light L reflected by the first concave mirror 31. The convex mirror 32 is configured to reflect the image light L reflected by the first concave mirror 31 in a direction different from the direction toward the first concave mirror 31. The second concave mirror 33 is located on the optical path of the image light L reflected by the convex mirror 32. The second concave mirror 33 is configured to reflect the image light L reflected by the convex mirror 32 in a direction different from the direction toward the convex mirror 32, and to form an aerial image R of a real image. By including multiple reflective optical elements in the reflective optical system 3, an aerial image R with reduced distortion can be formed.

[0053] The first concave mirror 31 has a reflective surface 31a with a curvature of Sa1. The convex mirror 32 has a reflective surface 32a with a curvature of Sb. The second concave mirror 33 has a reflective surface 33a with a curvature of Sa2. The curvature Sa1 is calculated by taking a cross section along the optical axis of the image light L incident on the first concave mirror 31, where the length of the line segment LS connecting the two ends of the reflective surface 31a is 2 × H, and D is the maximum length of the line segment LS along the optical axis OA between a point on the reflective surface 31a and the line segment LS. MAX In that case, D MAX Defined by / H (see Figure 5). D MAX If / H changes depending on how the cross-section is taken, what is D when the position of the cross-section is changed? MAX The maximum value of / H may be defined as the curvature Sa1. The curvature Sb and curvature Sa2 are defined in the same way as curvature Sa1.

[0054] The aerial image display device 1 may be configured such that the curvature Sa1 of the first concave mirror 31 is greater than the curvature Sa2 of the second concave mirror 33, and the curvature Sa2 of the second concave mirror 33 is greater than the curvature Sb of the convex mirror 32. In this case, the first concave mirror 31, which reflects the image light L emitted from the display device 2 toward the convex mirror 32, can be placed close to the display device 2. As a result, the space occupied by the display device 2 and the reflective optical system 3 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 reflective surface 33a of the second concave mirror 33 can be shortened, thereby suppressing the loss of image light L due to unwanted scattering, interference, etc. As a result, the display quality of the aerial image display device 1 can be improved.

[0055] The aerial image display device 1 is configured to display an aerial image R using a reflective optical system 3 that includes a first concave mirror 31, a convex mirror 32, and a second concave mirror 33. Therefore, by appropriately designing the shapes of the reflective surfaces 31a, 32a, and 33a of the first concave mirror 31, the convex mirror 32, and the second concave mirror 33, it is possible to reduce the distortion of the aerial image R. Furthermore, since the aerial image display device 1 does not include optical elements (e.g., beam splitters, polarizing filters, etc.) that transmit or separate a portion of the incident image light L from the reflective optical system 3, it is possible to suppress a decrease in the brightness of the aerial image R. Alternatively, the aerial image display device 1 can reduce the brightness of the image 4 displayed on the display surface 2a while maintaining sufficient brightness of the aerial image R, thereby reducing the power consumption of the aerial image display device 1.

[0056] The aerial image display device 1 has a relatively small curvature Sb of the convex mirror 32, which suppresses the spreading of the image light L reflected by the convex mirror 32. As a result, it is possible to suppress the enlargement of the second concave mirror 33 that reflects the image light L reflected by the convex mirror 32. Furthermore, the convex mirror 32 is the optical component that contributes most to the enlargement of the aerial image R, and therefore is also the optical component that has the greatest influence on the distortion of the aerial image R. Because the curvature Sb of the convex mirror 32 is relatively small, the distortion of the aerial image R can be reduced.

[0057] The first concave mirror 31 may be equipped with an adjustment member to adjust its spatial position relative to the display device 2, such as its distance from the display device 2 and its inclination angle. The adjustment member may include, for example, a support member such as a rod installed on the back side of the first concave mirror 31, an axis member provided on the support member for rotating the support member and the first concave mirror 31, or a sliding mechanism for translating the support member and the first concave mirror 31. The adjustment member may be adjusted manually or electrically by a stepping motor or the like. Such adjustment members may also be provided on the convex mirror 32 and the second concave mirror 33.

[0058] The aerial image display device 1 may have a configuration in which the size (e.g., diameter, etc.) of the second concave mirror 33 is larger than the size (e.g., diameter, etc.) of the first concave mirror 31. This configuration makes it easier to display the magnified aerial image R. That is, the image light L propagates spatially with images that have been sequentially magnified by the first concave mirror 31 and the convex mirror 32, and the second concave mirror 33 makes it easy to reflect the image that has been most magnified at the end toward the virtual imaging surface 8 of the aerial image R. Also, if the second concave mirror 33 is relatively large, it becomes easy to make the shape of its reflection surface 33a a shape that corresponds to each of the multiple partial light beams contained in the image light L. As a result, it becomes possible to effectively reduce the distortion of the aerial image R.

[0059] The size of the first concave mirror 31 may be defined by the length of the maximum diameter of the reflective surface 31a of the first concave mirror 31 (which can also be called the length of the maximum diameter in a front view). The size of the second concave mirror 33 may be defined by the length of the maximum diameter of the reflective surface 33a of the second concave mirror 33 (which can also be called the length of the maximum diameter in a front view). For example, if the first concave mirror 31 is partially spherical, the front view shape of the reflective surface 31a of the first concave mirror 31 will be circular. In this case, the size, or dimension, of the first concave mirror 31 may be 2H (shown in Figure 5), which is the length of the line segment LS that passes over the center of the reflective surface 31a and connects both ends. The center of the reflective surface 31a is defined by the lowest point (maximum protrusion) of the curved reflective surface 31a. If the first concave mirror 31 is partially ellipsoidal, the front view shape of the reflective surface 31a of the first concave mirror 31 will be elliptical. In this case, the size of the first concave mirror 31 may be the length of the major axis of the line segment passing over the center of the reflective surface 31a and connecting its two ends. If the front view shape of the reflective surface 31a of the first concave mirror 31 is rectangular or the like, the size of the first concave mirror 31 may be the length of the maximum diameter (e.g., diagonal diameter) of the line segment passing over the center of the reflective surface 31a and connecting its two ends. The sizes of the second concave mirror 33 and the convex mirror 32 may be defined similarly.

[0060] The maximum diameter length of the first concave mirror 31 may be, for example, about 150 mm to 200 mm. The maximum diameter length of the second concave mirror 33 may be, for example, about 200 mm to 350 mm. The maximum diameter length of the convex mirror 32 may be, for example, about 100 mm to 150 mm.

[0061] The size of the first concave mirror 31 may be defined by the area of ​​the reflective surface 31a of the first concave mirror 31, or by the area of ​​the reflective surface 31a of the first concave mirror 31 in a front view. The size of the second concave mirror 33 may be defined by the area of ​​the reflective surface 33a of the second concave mirror 33, or by the area of ​​the reflective surface 33a of the second concave mirror 33 in a front view.

[0062] The first concave mirror 31 and the second concave mirror 33 may be free-form concave mirrors in which the shapes of the reflecting surfaces 31a and 33a are free-form surfaces. The convex mirror 32 may be a free-form convex mirror in which the shape of the reflecting surface 32a is a free-form surface. When the shapes of the reflecting surfaces 31a, 32a, and 33a of the first concave mirror 31, the convex mirror 32, and the second concave mirror 33 are free-form surfaces, it becomes easy to make the shapes of the reflecting surfaces 31a, 32a, and 33a into shapes that effectively reduce the distortion of the virtual image R. As a result, it becomes possible to effectively reduce the distortion of the virtual image R.

[0063] The free-form surfaces that define the reflecting surfaces 31a, 32a, and 33 may be XY polynomial surfaces (also referred to as SPS XYP surfaces) defined by the following equations (1) and (2). The XY polynomial surface is expanded into a polynomial up to the 10th degree added to the reference conic surface. Therefore, in equations (1) and (2), the sum of m and n is 10 or less. In equation (1), z is the sag amount of a plane parallel to the z-axis (optical axis), c is the vertex curvature, r is the radial distance (i.e., r 2 = x 2 + y 2 ), k is the conic constant, and Cj is the coefficient of the monomial x m y n .

Equation

Equation

[0064] When viewing the second concave mirror 33 from the back side along a direction parallel to the virtual imaging plane 8 of the aerial image R (the Y direction in Figures 1A and 1B), the reflective surface 33a of the second concave mirror 33 may overlap with the display surface 2a of the display device 2, the reflective surface 31a of the first concave mirror 31, and the reflective surface 32a of the convex mirror 32. In this case, the space occupied by the display device 2 and the reflective optical system 3 can be reduced, allowing the aerial image display device 1 to be miniaturized. As a result, the optical path length of the image light L inside the aerial image display device 1 can be shortened, thereby suppressing the loss of image light L due to unwanted scattering, interference, etc. Ultimately, the display quality of the aerial image display device 1 can be improved.

[0065] When the second concave mirror 33 is viewed from the back side along a direction (Y direction) parallel to the virtual imaging plane 8 of the aerial image R, the reflective surface 33a of the second concave mirror 33 may encompass the display surface 2a of the display device 2, the reflective surface 31a of the first concave mirror 31, and the reflective surface 32a of the convex mirror 32. In this case, the space occupied by the display device 2 and the reflective optical system 3 can be further reduced, and the aerial image display device 1 can be made more compact.

[0066] Since user 5 views the aerial image R from a direction almost perpendicular to the virtual imaging plane 8, the direction of the aerial image R parallel to the virtual imaging plane 8 (the Y direction in Figures 1A and 1B) corresponds to the height direction of the aerial image display device 1. Also, the direction of the aerial image R perpendicular to the virtual imaging plane 8 corresponds to the thickness direction (depth direction) of the aerial image display device 1. When the second concave mirror 33 is viewed from the back side along the direction parallel to the virtual imaging plane 8 (the Y direction), the reflective surface 33a overlaps with the display surface 2a, the reflective surface 31a, and the reflective surface 32a, or encloses the display surface 2a, the reflective surface 31a, and the reflective surface 32a, thereby making the thickness (depth) of the aerial image display device 1 thinner.

[0067] Next, another example of the aerial image display device 1 will be described. The backlight 21 of the transmissive display device 2 may be configured such that, as shown in Figure 6, a plurality of visible light emitting units 21a are arranged in a first region 23a1 of the first surface 23a, and a plurality of infrared light emitting units 21b are arranged in a second region 23a2 of the first surface 23a. The second region 23a2 is a region that does not overlap with the first region 23a1 in a planar view. By arranging the plurality of visible light emitting units 21a and the plurality of infrared light emitting units 21b in different regions, it is possible to suppress the transmission of white light emitted from the visible light emitting units 21a through the sub-pixels for infrared emission. In addition, it is possible to suppress the transmission of infrared light emitted from the infrared light emitting units 21b through the sub-pixels for red emission, green emission, and blue emission. This makes it possible to improve the image quality of the visible light image and infrared light image displayed on the display surface 2a. Even when multiple visible light emitting units 21a and multiple infrared light emitting units 21b are arranged in different regions, by appropriately designing the reflective optical system 3, it is possible to form a visible light aerial image R1 and an infrared light aerial image R2 at any position on the virtual imaging plane 8.

[0068] By arranging multiple visible light emitting units 21a and multiple infrared light emitting units 21b in different regions, when only the multiple visible light emitting units 21a are illuminated, only a visible light image can be displayed. When only the multiple infrared light emitting units 21b are illuminated, only an infrared light image (thermal image) can be displayed, and the aerial image display device 1 can be used as a heater during cold periods such as winter. By illuminating both the multiple visible light emitting units 21a and the multiple infrared light emitting units 21b, a portion of the image 4 may be a visible light image, and the other portion of the image 4 may be a thermal image. In this case, the visible light image may be a bright image with high brightness, such as the sun, to provide the user with a visual sense of warmth.

[0069] The self-emissive display device 2 may have a configuration in which multiple visible light emitting units 24a are arranged in a first region 23a1 of the first surface 23a, and multiple infrared light emitting units 24b are arranged in a second region 23a2 of the first surface 23a, as shown in Figure 7. The second region 23a2 is a region that does not overlap with the first region 23a1 in a plan view. By arranging the multiple visible light emitting units 24a and the multiple infrared light emitting units 24b in different regions, the arrangement of the multiple visible light emitting units 24a and the arrangement of the multiple infrared light emitting units 24b can be optimized. This makes it possible to improve the image quality of the visible light image and infrared light image displayed on the display surface 2a. Even when the multiple visible light emitting units 24a and the multiple infrared light emitting units 24b are arranged in different regions, it is possible to form a visible light aerial image R1 and an infrared light aerial image R2 at any position on the virtual imaging surface 8 by appropriately designing the reflective optical system 3.

[0070] By arranging multiple visible light emitting units 24a and multiple infrared light emitting units 24b in different regions, when only the multiple visible light emitting units 24a are illuminated, only a visible light image can be displayed. When only the multiple infrared light emitting units 24b are illuminated, only an infrared light image (thermal image) can be displayed, and the aerial image display device 1 can be used as a heater during cold periods such as winter. By illuminating both the multiple visible light emitting units 24a and the multiple infrared light emitting units 24b, a portion of the image 4 may be a visible light image, and the other portion of the image 4 may be a thermal image. In this case, the visible light image may be a bright image with high brightness, such as the sun, to provide the user with a visual sense of warmth.

[0071] Next, an aerial image display device of another embodiment of the present disclosure will be described. Figure 8 is a diagram showing the configuration of an aerial image display device of another embodiment of the present disclosure. The aerial image display device 1A of this embodiment differs from the aerial image display device 1 in the configuration of the reflective optical system, but otherwise has the same configuration. Therefore, the same reference numerals are used for the same components as in the aerial image display device 1, and a detailed explanation is omitted.

[0072] The aerial image display device 1A of this embodiment comprises a display device 2 and a reflective optical system 3A. As shown in Figure 8, the reflective optical system 3A is composed of a first concave mirror 31 and a second concave mirror 33. The first concave mirror 31 is located on the optical path of the image light L emitted from the display device 2. The first concave mirror 31 reflects the image light L emitted from the display device 2 in a direction different from the direction toward the display device 2. The second concave mirror 33 is located on the optical path of the image light L reflected by the first concave mirror 31. The second concave mirror 33 reflects the image light L reflected by the first concave mirror 31 in a direction different from the direction toward the first concave mirror 31.

[0073] The first concave mirror 31 has a reflective surface 31a with a curvature of Sa1. The second concave mirror 33 has a reflective surface 33a with a curvature of Sa2. The curvature of the first concave mirror 31 (Sa1) may be greater than the curvature of the second concave mirror 33 (Sa2). This allows the first concave mirror 31, which reflects the image light L emitted from the display device 2 toward the second concave mirror 33, to be positioned close to the display device 2. As a result, the space occupied by the display device 2 and the reflective optical system 3 can be reduced, thus enabling miniaturization of the aerial image display device 1A. Furthermore, because the aerial image display device 1A can be miniaturized, the optical path length of the image light L between the display surface 2a of the display device 2 and the reflective surface 33a of the second concave mirror 33 can be shortened, thereby suppressing the loss of image light L due to unwanted scattering, interference, etc. As a result, the display quality of the aerial image display device 1A can be improved.

[0074] The first concave mirror 31 and the second concave mirror 33 may be free-form concave mirrors in which the shape of the reflective surfaces 31a and 33a is a free-form surface. When the shape of the reflective surfaces 31a and 33a of the first concave mirror 31 and the second concave mirror 33 is a free-form surface, it becomes easier to make the shape of the reflective surfaces 31a and 33a a shape that effectively reduces the distortion of the aerial image R. As a result, it becomes possible to effectively reduce the distortion of the aerial image R.

[0075] Similar to the aerial image display device 1, the aerial image display device 1A can provide users 5 with a new visual experience using infrared light.

[0076] The aerial image display device 1A, like the aerial image display device 1, may not display a visible light image on the display surface 2a, but may only display an infrared light image. In other words, the aerial image display device 1A, like the aerial image display device 1, may be used as a heater.

[0077] Next, an aerial image display device of another embodiment of the present disclosure will be described. Figure 9 shows the configuration of an aerial image display device 1B of another embodiment of the present disclosure. The aerial image display device 1B of this embodiment differs from the aerial image display device 1 in that it is equipped with a stimulus signal irradiation unit 66 that irradiates the user's body with a stimulus signal 66a. In addition, the aerial image display device 1B does not have a time lag control unit 7. As the aerial image display device 1B has the same configuration as the aerial image display device 1, similar components are given the same reference numerals as the aerial image display device 1 and detailed descriptions are omitted.

[0078] The aerial image display device 1B is configured to include a stimulus signal emitting unit 66 that, when a part of the user's body (for example, a part of the finger 5f of the hand 5h) comes into contact with the high-temperature image unit 43 in the aerial image R, emits a stimulus signal 66a to a part of the user's finger 5f that is offset from the part of the user's finger 5f. This configuration produces the following effects. For example, as shown in Figure 10, when a temperature stimulus is applied to a certain part f1 of the finger 5f using infrared light L2, and at the same time a tactile stimulus is applied to another part f2 of the finger 5f using a stimulus signal 66a, an illusion phenomenon (also called the cross-temperature reference effect) occurs in which the temperature stimulus at part f1 moves to the part f2 that received the tactile stimulus. This extends the temperature stimulus in the depth direction, giving depth to the sensation of warmth, and by combining this with a depth-based image, a new, more realistic visual experience can be provided to the user 5.

[0079] The part of user 5's body to which the stimulus signal 66a is irradiated may be a part of the fingers 5f of user 5h, a part of the palm of user 5h, a part of the back of user 5h, a part of user 5's arm, etc.

[0080] The stimulus signal 66a may be a tactile-inducing signal that induces a sense of touch in the user 5. The tactile-inducing signal may be a sound wave signal or ultrasonic signal, which are air vibrations, or wind (airflow), which are air pressure. Of these, ultrasonic signals have the advantage of not interfering with the aerial image R because they are not audible to the user 5. The frequency of the ultrasonic signal may be around 20 kHz or higher, and may be around 20 kHz to 20 MHz. In this case, the stimulus signal irradiation unit 66 may be an ultrasonic signal generator. The ultrasonic signal generator may be, for example, an aerial tactile presentation device (aerial haptics) that includes an electro-ultrasonic converter array (also called an ultrasonic transducer array) and generates a sense of touch in space by aggregating multiple ultrasonic signals emitted from the ultrasonic transducer array by phase control.

[0081] The stimulus signal 66a may be a thermoregulatory signal that induces a sensation of warmth. The thermoregulatory signal may be a near-infrared signal, an infrared signal, or a hot air (hot airflow). When the thermoregulatory signal is a near-infrared signal or an infrared signal, there is an advantage that the thermoregulatory signal can be precisely and accurately irradiated onto a part of the user's body. The thermoregulatory signal may provide a thermoregulatory (temperature) to a part of the user's body that is higher than the thermoregulatory (temperature) of the high-temperature image unit 43. In this case, a clearer cross-temperature reference can be provided to a part of the user's body. The thermoregulatory signal may provide a thermoregulatory (temperature) to a part of the user's body that is more than 1 times and about 2 times higher than the thermoregulatory (temperature) of the high-temperature image unit 43, but is not limited to this range.

[0082] The stimulation signal irradiation unit 66 irradiates a stimulation signal 66a to a part f2 of the user's finger 5f that is offset from part f1 of the user's finger 5f. The degree of offset (distance difference) between part f1 and part f2 may be approximately 10 mm to 80 mm. In other words, the distance difference at which the cross-temperature reference effect occurs may be approximately 10 mm to 80 mm. Below 10 mm, it tends to be difficult to impart depth to the warmth sensation. Above 80 mm, it tends to be difficult for cross-temperature reference to occur.

[0083] The aerial image display device 1B may include a detection unit 65 that detects when a part of the user's body (such as a finger 5f) comes into contact with the high-temperature image section 43 in the aerial image R. The detection unit 65 may be, for example, an imaging device such as a camera. The detection unit 65 may also be a light (electromagnetic wave) detection device that detects the reflection, passage, or non-passage of visible light, laser light, infrared light, electromagnetic waves, etc. The light (electromagnetic wave) detection device may have a light-emitting unit for visible light, etc., and a light-receiving unit for visible light, etc., and may be configured to detect when the light-receiving unit receives reflected light reflected by the finger 5f, etc. (when there is an output from the light-receiving unit), thereby detecting when the finger 5f, etc. has come into contact with the high-temperature image section 43 in the aerial image R. Alternatively, the light detection device may have a light-emitting unit for visible light, etc., and a light-receiving unit for visible light, etc., and may be configured to detect when the light reception at the light-receiving unit is blocked by the finger 5f, etc. (when there is no output from the light-receiving unit), thereby detecting when the finger 5f, etc., has come into contact with the high-temperature image section 43 in the aerial image R. Furthermore, the detection unit 65 may be a sound wave detection device that detects the reflection, passage, or non-passage of sound waves or ultrasonic waves. Its operating principle may be the same as that of a light detection device.

[0084] Figure 11 shows the configuration of an aerial image display device 1C of another embodiment of the present disclosure. The aerial image display device 1C of this embodiment differs from the aerial image display device 1A in that it includes a stimulus signal irradiation unit 66 that irradiates the user's body with a stimulus signal 66a. In addition, the aerial image display device 1C does not include a time lag control unit 7. As the aerial image display device 1C has the same configuration as the aerial image display device 1A, similar components are given the same reference numerals as the aerial image display device 1A and detailed descriptions are omitted.

[0085] The aerial image display device 1C is equipped with a reflective optical system 3A. The reflective optical system 3A consists of a first concave mirror 31 and a second concave mirror 33, and does not have a convex mirror 32. This allows for a miniaturized aerial image display device 1C, and by extending the temperature stimulus in the depth direction to give depth to the thermal sensation, and combining it with a depth-of-field image, it is possible to provide the user 5 with a new, more realistic visual experience.

[0086] The aerial image display devices 1, 1A, 1B, and 1C may be head-up displays installed in a vehicle. In this case, for example, a part of the vehicle's front windshield may be used as a reflective material, and this reflective material may be used in place of the second concave mirror 33. The configuration may be such that the user views the aerial image R through the reflective material. The reflective material may be of the semi-transmissive reflective type (transmitting about half of the light and reflecting about half of the light).

[0087] The aerial image display devices 1, 1A, 1B, and 1C may be configured such that, in the vertical cross-sections shown in Figures 1A, 1B, 9, and 11, the display device 2 (and convex mirror 32) is positioned between the first concave mirror 31 and the second concave mirror 33 when viewed from the side. In other words, the first concave mirror 31 may be at the lowest position and the second concave mirror 33 may be at the highest position. In this case, it becomes easier to reduce the height of the aerial image display devices 1, 1A, 1B, and 1C and to miniaturize them.

[0088] Although embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to the embodiments described above, and various modifications and improvements are possible without departing from the gist of the present disclosure. For example, the size of the infrared light emitting unit 21b may be smaller than the size of the visible light emitting unit 21a. This is because the transmittance of infrared light to the liquid crystal panel 22 is higher than the transmittance of visible light to the liquid crystal panel 22. By using a small infrared light emitting unit 21b with low light emission intensity, the power consumption of the infrared light emitting unit 21b can be reduced.

[0089] As described above, the display device and aerial image display device of this disclosure can provide users with a new video experience using infrared light.

[0090] This disclosure can be implemented in the following configurations (1) to (19). (1) Equipped with a display unit, A display device that, when the image displayed by the display unit includes a high-temperature image unit that shows a high-temperature object at a temperature higher than a predetermined temperature, displays the high-temperature image unit using light including infrared light.

[0091] (2) A display unit having a display surface, The system includes a reflective optical system that reflects the image light of the image displayed on the display surface and forms an aerial image of the real image, An aerial image display device that, when the aforementioned image includes a high-temperature image portion that shows a high-temperature object at a temperature higher than a predetermined temperature, displays the high-temperature image portion on the display surface using light including infrared light.

[0092] (3) The aerial image display device according to configuration (2), which is capable of displaying the high-temperature image section as a video.

[0093] (4) Equipped with a temperature detection unit that detects ambient temperature, The aerial image display device according to configuration (2) or (3), wherein the predetermined temperature is the temperature detected by the temperature detection unit.

[0094] (5) Further including a light emission control unit, The display unit has a plurality of visible light emitting units and a plurality of infrared light emitting units. The aerial image display device according to any one of configurations (2) to (4), wherein the light emission control unit enables the display of a high-temperature image by controlling the emission and non-emission of the plurality of visible light emission units and the plurality of infrared light emission units.

[0095] (6) The aerial image display device according to configuration (5), wherein the plurality of visible light emitting units and the plurality of infrared light emitting units are arranged alternately in a matrix.

[0096] (7) The high-temperature image unit is composed of a visible light image displayed by visible light and an infrared light image displayed by infrared light, The aerial image display device according to any one of configurations (2) to (6), wherein the infrared light image has a size that encloses the visible light image on the display surface.

[0097] (8) The aerial image display device according to configuration (7), wherein the infrared light image has a temperature gradient portion on the display surface around the visible light image, where the intensity of the infrared light decreases as it moves away from the center of the visible light image.

[0098] (9) Further including a time lag control unit, When the high-temperature image section is displayed as a video, the time lag control unit delays the movement of the infrared light image in time relative to the movement of the visible light image, as described in configuration (7) or (8).

[0099] (10) An aerial image display device according to any one of configurations (2) to (9), comprising a stimulus signal irradiation unit that irradiates a stimulus signal to a part of the user's body that is offset from the part of the user's body when a part of the user's body comes into contact with the high-temperature image part of the aerial image.

[0100] (11) The aerial image display device according to configuration (10), wherein the stimulus signal is a tactile-inducing signal that induces touch.

[0101] (12) The aerial image display device according to configuration (10), wherein the stimulus signal is a temperature-inducing signal that induces a temperature sensation.

[0102] (13) The aerial image display device according to any one of configurations (2) to (12), wherein the high-temperature object includes at least one of a person, an animal, a character, and a heating element.

[0103] (14) The reflective optical system is A first concave mirror that reflects the aforementioned image light in a direction different from the direction toward the display unit, A convex mirror that reflects the image light reflected by the first concave mirror in a direction different from the direction toward the first concave mirror, An aerial image display device according to any one of configurations (2) to (13), comprising: a second concave mirror that reflects the image light reflected by the convex mirror in a direction different from the direction toward the convex mirror, and forms an aerial image of a real image.

[0104] (15) The aerial image display device according to configuration (14), wherein when the curvature of the first concave mirror is Sa1, the curvature of the convex mirror is Sb, and the curvature of the second concave mirror is Sa2, Sa1 > Sa2 > Sb.

[0105] (16) The first concave mirror and the second concave mirror are free-form concave mirrors, The aerial image display device according to configuration (14) or (15), wherein the convex mirror is a free-form convex mirror.

[0106] (17) The reflective optical system includes a first concave mirror that reflects the image light in a direction different from the direction toward the display device, An aerial image display device according to any one of configurations (2) to (13), comprising: a second concave mirror that 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 aerial image of a real image.

[0107] (18) The aerial image display device according to configuration (17), wherein the curvature of the first concave mirror is greater than the curvature of the second concave mirror.

[0108] (19) The aerial image display device according to configuration (17) or (18), wherein the first concave mirror and the second concave mirror are free-form concave mirrors. Industrial application fields

[0109] The aerial image display device disclosed herein enables touchless operation of aerial images and can be used in a variety of product fields, including, but is not limited to, the following: for example, communication devices that conduct conversations and communications with aerial images; medical consultation devices in which doctors conduct interviews with patients through aerial images; navigation devices and driving control devices for vehicles such as automobiles; order placement and receiving devices and cash register devices for stores, etc.; operation panels for buildings, elevators, etc.; learning devices that conduct or receive lessons with aerial images; office equipment that conducts business communications and instructions with aerial images; amusement machines that play games with aerial images; projection devices that project images onto the ground, building walls, etc. in amusement parks, game centers, etc.; simulator devices that conduct simulated experiments using aerial images in universities, medical institutions, etc.; large displays that display prices, etc. in markets, stock exchanges, etc.; and video viewing devices for viewing aerial images. [Explanation of Symbols]

[0110] 1,1A,1B,1C Aerial image display device 2 Display section (display device) 2a Display surface 21 Backlight 21a Visible light emitting section 21b Infrared light emitting section 22 LCD panels 23 circuit boards 23a 1st page 23a1 1st area 23a2 2nd area 24 pixels 24a Visible light emitting section 24aR Red Light-Emitting Device 24aG Green Light-Emitting Device 24aB Blue Light-Emitting Device 24b Infrared light emitting section 24bI Infrared Light-Emitting Device 3,3A reflective optics 31 1st concave mirror 31a Reflective surface 32 Convex mirror 32a Reflective surface 33 Second concave mirror 33a Reflective surface 4th Grade 43 High-temperature image section 43a Visible light image 43b Infrared light image 43ba temperature gradient section 44 Room temperature image section 5 User 6. Light emission control unit 7. Time Lag Control Unit 8. Virtual imaging plane 50 Storage section 60 Temperature Sensors 65 Detection unit 66 Stimulus signal irradiation section 66a Stimulus signal

Claims

1. A display unit having a display surface and having a plurality of visible light emitting units and a plurality of infrared light emitting units, A reflective optical system that reflects the image light of the image displayed on the aforementioned display surface and forms an aerial image of the real image, A storage unit that stores high-temperature images of objects at temperatures higher than a predetermined temperature as distinguishable image data, The system includes a light emission control unit that controls the plurality of visible light emission units and the plurality of infrared light emission units based on the image data, An aerial image display device comprising: an emission control unit that controls the visible light emission unit and the infrared light emission unit to display the high-temperature image unit using light including infrared light emitted by the infrared light emission unit.

2. A temperature detection unit for detecting ambient temperature, The predetermined temperature is the ambient temperature. The aerial image display device according to claim 1, wherein the storage unit stores the image data and image temperature in association in advance, and distinguishes the high-temperature image portion in the image data based on a comparison of the ambient temperature and the image temperature.

3. The aerial image display device according to claim 1 or 2, which is capable of displaying the high-temperature image section as a video.

4. The aerial image display device according to claim 1 or 2, wherein the light emission control unit enables the display of a high-temperature image by controlling the emission and non-emission of the plurality of visible light emission units and the plurality of infrared light emission units.

5. The aerial image display device according to claim 4, wherein the plurality of visible light emitting units and the plurality of infrared light emitting units are arranged alternately in a matrix.

6. The high-temperature image unit is composed of a visible light image displayed by visible light and an infrared light image displayed by infrared light. The aerial image display device according to claim 1 or 2, wherein the infrared light image has a size that encloses the visible light image on the display surface.

7. The storage unit stores, around the visible light image, as image data that can distinguish temperature gradient areas where the intensity of infrared light decreases as it moves away from the center of the visible light image, The aerial image display device according to claim 6, wherein the light emission control unit controls the infrared light emission unit to display the temperature gradient using infrared light emitted by the infrared light emission unit.

8. Further including a time lag control unit, The aerial image display device according to claim 6, wherein, when the high-temperature image section is displayed as a video, the time lag control unit delays the movement of the infrared light image in time relative to the movement of the visible light image.

9. The aerial image display device according to claim 1 or 2, further comprising a stimulus signal irradiation unit that irradiates a stimulus signal at a position separated from the aerial image.

10. The aerial image display device according to claim 9, wherein the stimulus signal is a tactile-inducing signal that induces touch.

11. The aerial image display device according to claim 9, wherein the stimulus signal is a temperature-inducing signal that induces a sensation of warmth.

12. The aerial image display device according to claim 1 or 2, wherein the high-temperature object includes at least one of a person, an animal, a character, and a heating element.

13. The aforementioned reflective optical system is A first concave mirror that reflects the aforementioned image light in a direction different from the direction toward the display unit, A convex mirror that reflects the image light reflected by the first concave mirror in a direction different from the direction toward the first concave mirror, A second concave mirror reflects the image light reflected by the convex mirror in a direction different from the direction toward the convex mirror, and forms an aerial image of a real image. An aerial image display device according to claim 1 or 2, having the following features.

14. The aerial image display device according to claim 13, wherein when the curvature of the first concave mirror is Sa1, the curvature of the convex mirror is Sb, and the curvature of the second concave mirror is Sa2, Sa1 > Sa2 > Sb.

15. The first concave mirror and the second concave mirror are free-form concave mirrors. The aerial image display device according to claim 13, wherein the convex mirror is a free-form convex mirror.

16. The reflective optical system includes a first concave mirror that reflects the image light in a direction different from the direction toward the display unit, A second concave mirror 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 aerial image of a real image. An aerial image display device according to claim 1 or 2, having the following features.

17. The aerial image display device according to claim 16, wherein the curvature of the first concave mirror is greater than the curvature of the second concave mirror.

18. The aerial image display device according to claim 16, wherein the first concave mirror and the second concave mirror are free-form concave mirrors.

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