Aerial image display device

Abstract

An aerial image display device disposed on a first reflection surface of a reflection member comprises a display, a set of a reflective polarizing film and a beam splitter provided at an angle at which first emission light can be received from the display, a reflector provided at an angle at which first reflected light can be received from the set of the reflective polarizing film and the beam splitter, and a wavelength plate provided between the reflector and the beam splitter. The display emits the first emission light, which is first linearly polarized light. The set of the reflective polarizing film and the beam splitter receives the first emission light and reflects the first emission light as the first reflected light. A set of the reflector and the wavelength plate receives the first reflected light, which is first linearly polarized light, and retroreflects the first reflected light as first retroreflected light that is second linearly polarized light orthogonal to the first linearly polarized light. The set of the reflective polarizing film and the beam splitter transmits the first retroreflected light as first transmitted light. The first reflection surface receives the first transmitted light, reflects the first transmitted light as first imaging light, and displays a first aerial image.

Description

Aerial image display device

[0001] The embodiment relates to an aerial image display device.

[0002] Aerial image display technology has been proposed that displays aerial images of objects in empty space as if they were actually present. For example, aerial image optical systems using retrotransmissive or retroreflective elements such as micro mirror array plates (MMAPs) can be combined with a reflective surface to create a portable tabletop aerial image optical system (PortOn).

[0003] Hirotsugu Yamamoto, "Aerial display using aerial imaging by retroreflection (AIRR)," Journal of the Imaging Society of Japan, 2017, Vol. 56, No. 4, pp. 341-351; Hiroki Yamamoto, Hajime Kajita, Naoya Koizumi, Ken Naemura, "EnchanTable: Upright aerial image display using table surface reflection," Transactions of the Virtual Reality Society of Japan, 2016, Vol. 21, No. 3, pp. 401-410; Kota Murofushi, Naoki Hashimoto, "Expanding the viewing zone of stereoscopic aerial images by combining multiple stereoscopic displays," Transactions of the Virtual Reality Society of Japan, 2020, Vol. 25, No. 4, pp. 432-438

[0004] However, in a tabletop aerial imaging optical system using MMAP, a view-control film is used to remove transmitted light, which is unnecessary light other than the aerial image. The use of a view-control film raises concerns that the brightness and image quality of the aerial image may be reduced.

[0005] The present invention has been made in light of the above-mentioned circumstances, and its purpose is to provide a means for removing transmitted light in a tabletop aerial image display device while maintaining a high brightness of the aerial image.

[0006] An aerial image display device of one embodiment is disposed on a first reflecting surface of a reflecting member and includes a display, a reflective polarizing film, a beam splitter, a reflector, and a wave plate. The pair of the reflective polarizing film and the beam splitter is disposed at an angle that allows it to receive a first emitted light from the display. The reflector is disposed at an angle that allows it to receive the first reflected light from the pair of the reflective polarizing film and the beam splitter. The wave plate is disposed between the reflector and the beam splitter. The display emits the first emitted light, which is a first linearly polarized light. The pair of the reflective polarizing film and the beam splitter receives the first emitted light and reflects it as a first reflected light. The pair of the reflector and the wave plate receives the first reflected light, which is the first linearly polarized light, and retroreflects it as a first retroreflected light, which is a second linearly polarized light orthogonal to the first linearly polarized light. The pair of the reflective polarizing film and the beam splitter transmits the first retroreflected light as a first transmitted light. The first reflecting surface receives the first transmitted light and reflects it as first imaging light, thereby displaying a first aerial image.

[0007] According to the embodiment, it is possible to provide a means for removing transmitted light while maintaining high brightness of the aerial image in a tabletop aerial image display device.

[0008] FIG. 1 is a block diagram showing the overall configuration of an aerial image display system according to a first embodiment. FIG. 2 is a plan view showing an example of an aerial image display device according to the first embodiment. FIG. 3 is a plan view showing an example of an imaging optical path of an aerial image displayed by the aerial image display device according to the first embodiment. FIG. 4 is a plan view showing an example of an aerial image display device according to a second embodiment. FIG. 5 is a plan view showing an example of an imaging optical path of an aerial image displayed by the aerial image display device according to the second embodiment. FIG. 6 is a plan view showing an example of an aerial image display device according to a third embodiment. FIG. 7 is a plan view showing an example of an imaging optical path of an aerial image displayed by the aerial image display device according to the third embodiment. FIG. 8 is a plan view showing an example of an aerial image display device according to a fourth embodiment. FIG. 9 is a plan view showing an example of an imaging optical path of an aerial image displayed by the aerial image display device according to the fourth embodiment.

[0009] Hereinafter, several embodiments will be described with reference to the drawings. In the following description, components having the same functions and configurations will be given the same reference numerals.

[0010] 1. First Embodiment An aerial image display device according to a first embodiment will be described.

[0011] 1.1 Configuration of the Aerial Image Display System Fig. 1 is a block diagram showing the overall configuration of an aerial image display system according to the first embodiment. As shown in Fig. 1, an aerial image display system 5 includes an aerial image display device 1 of the first embodiment, a reflecting member 2, and a control device 9. The aerial image display device 1 displays an aerial image. For example, the aerial image display device 1 can display an image in the air on the reflecting member 2. Details of the configurations of the aerial image display device 1 and the reflecting member 2 will be described later.

[0012] The control device 9 controls the aerial image display device 1. The control device 9 includes a processor 90, a read only memory (ROM) 91, a random access memory (RAM) 92, a storage 93, and an interface 94.

[0013] The processor 90 is a processing circuit capable of executing various programs. The processor 90 controls the overall operation of the system including the aerial image display device 1. The processor 90 includes a CPU (Central Processing Unit) and / or a GPU (Graphics Processing Unit). Note that multiple processors 90 may be provided within the control device 9.

[0014] The ROM 91 is a non-volatile semiconductor memory such as an EEPROM (registered trademark), and stores programs, control data, and the like for controlling the aerial image display device 1.

[0015] The RAM 92 is a volatile semiconductor memory such as a dynamic RAM (DRAM) or a static RAM (SRAM). The RAM 92 is used as a working area for the processor 90.

[0016] The storage 93 is a non-volatile storage device such as a hard disc drive (HDD), a solid state drive (SSD), or a memory card. The storage 93 stores various types of information and various types of data. Programs and control data may be stored in the storage 93. The storage 93 stores, for example, image data to be projected onto the aerial image display device 1.

[0017] The interface 94 includes various connectors, various ports, a signal processing circuit, a communication module, etc. The interface 94 connects the control device 9 to the aerial image display device 1. The interface 94 is responsible for inputting and outputting information and data, various processes on information and data, and various controls for acquiring information and data. The interface 94 accepts input from a user of the aerial image display device 1 via input devices (not shown) such as a touch panel, a keyboard, a mouse, operation buttons, and a microphone. The interface 94 provides various information and data to a user of the aerial image display device 1 via output devices (not shown) such as a display and a speaker. The interface 94 can transfer information and data between the aerial image display device 1 and the control device 9 via communication via a wireless or wired network. The interface 94 sends various control signals from the processor 90 to the aerial image display device 1. The interface 94 sends various control signals from the aerial image display device 1 to the processor 90.

[0018] The aerial image display device 1 described below is a device equipped with a real image optical system configured to display a real aerial image on a reflecting member 2 based on a display image displayed on the display surface of a display. The real aerial image displayed by the aerial image display device 1 is displayed in a direction approximately perpendicular to the reflecting surface of the reflecting member 2. For convenience of explanation, the plane parallel to the reflecting surface of the reflecting member 2 provided in the aerial image display system 5 is referred to as the XY plane. The plane parallel to the display surface of the real aerial image is referred to as the YZ plane. The direction where the XY plane and the YZ plane intersect is referred to as the Y direction. The direction perpendicular to the Y direction in the XY plane is referred to as the X direction. The direction perpendicular to the Y direction in the YZ plane is referred to as the Z direction. The user's line of sight LOS is assumed to coincide with the direction obtained by combining the +X direction and the -Z direction. The opposite direction of the user's line of sight LOS (i.e., the direction approaching the user) is assumed to coincide with the direction obtained by combining the -X direction and the +Z direction.

[0019] Fig. 2 is a plan view showing an example of the aerial image display device according to the first embodiment. Fig. 1 shows the planar positional relationship between the reflecting member 2 and the aerial image display device 1 when viewed in the Y direction (in the ZX plan view as viewed from the -Y side).

[0020] The aerial image display device 1 is disposed on a reflecting member 2 .

[0021] The reflecting member 2 has a reflecting surface configured to reflect incident light. The reflecting surface of the reflecting member 2 includes a mirror, a glossy table surface, etc. The reflecting member 2 also includes, for example, a half mirror or a glossy film provided on a non-glossy surface. The reflecting member 2 also includes, for example, a non-glossy surface to which a glossing agent is applied.

[0022] The reflecting member 2 may have a reflective polarizing film attached to its reflective surface. By attaching a reflective polarizing film to the reflecting member 2, for example, it is possible to improve the reflection efficiency of the reflective surface. The reflecting member 2 may also be included in the aerial image display device 1. That is, the aerial image display device 1 may be equipped with a reflective member 2 such as a half mirror.

[0023] The aerial image display device 1 includes a display 10, a reflective polarizing film 11, a beam splitter 12, a wave plate 13, and a reflector 14.

[0024] The beam splitter 12 is, for example, a polarizing beam splitter. The beam splitter 12 transmits and reflects light of the same polarization state. Hereinafter, the polarization state of the light that transmits through the beam splitter 12 will be referred to as S-polarized light, and the polarization state of the light that is reflected by the beam splitter 12 will be referred to as P-polarized light.

[0025] The beam splitter 12 is disposed inside the aerial image display device 1 at an arbitrary angle α in the negative direction (clockwise) with respect to the reflecting surface of the reflecting member 2 when viewed in the Y direction (in the ZX plane viewed from the -Y side). When viewed in the Y direction, one end of the beam splitter 12 intersects with one end of the reflecting member 2 or an extension thereof toward the inside of the aerial image display device 1. The intersection point between the beam splitter 12 and the reflecting member 2 is sometimes referred to as the starting point A1. The reflecting surface of the beam splitter 12 is disposed so as to face the inside of the aerial image display device 1. The angle α will be described later.

[0026] The reflective polarizing film 11 reflects, for example, P-polarized light and transmits S-polarized light. The reflective polarizing film 11 is attached to the reflective surface of the beam splitter 12. The reflective surface of the reflective polarizing film 11 is positioned so that it faces the inside of the aerial image display device 1.

[0027] The reflector 14 has a reflective surface configured to retroreflect incident light. The reflective surface of the reflector 14 is positioned so as to face the inside of the aerial image display device 1. The reflector 14 is positioned inside the aerial image display device 1 at an arbitrary angle β in the positive direction (counterclockwise) with respect to the reflective surface of the reflective polarizing film 11 when viewed in the Y direction. When viewed in the Y direction, one end of the reflector 14 intersects with the other end of the beam splitter 12 (the end opposite the starting point A1) or its extension. The intersection point between the reflector 14 and the beam splitter 12 is sometimes referred to as the starting point B1. The angle β will be described later.

[0028] The wave plate 13 is, for example, a λ / 4 wave plate. The wave plate 13 is configured to output incident light with a phase shift of π / 2 between P-polarized light and S-polarized light. The wave plate 13 is attached to the reflective surface of the reflector 14. In other words, the wave plate 13 is disposed so as to face the reflective surface of the reflective polarizing film 11.

[0029] The display 10 is, for example, a polarized display, and emits, for example, P-polarized light.

[0030] The display 10 is disposed so that its display surface faces the inside of the aerial image display device 1. When viewed in the Y direction, one end of the display 10 is disposed so as to intersect with the other end of the reflector 14 (the end opposite the starting point B1). In the first embodiment, the intersection of the display 10 and the reflector 14 may be referred to as starting point C1. The position of the other end of the display 10 (the end opposite the starting point C1) may be referred to as starting point D1.

[0031] The distance between the starting point A1 and the starting point C1 has a length H (H is a positive real number). For example, when viewed in the Y direction, the display 10 is disposed tilted in the positive direction (counterclockwise) with respect to the line segment connecting the starting point A1 and the starting point C1. When viewed in the Y direction, the angle that the display 10 forms with respect to the wave plate 13 in the positive direction (counterclockwise) may be referred to as an arbitrary angle γ.

[0032] The orientations of display 10 and beam splitter 12 are adjusted so that P-polarized light emitted from display 10 is incident on the reflective surface of reflective polarizing film 11. Similarly, the orientations of beam splitter 12 and reflector 14 are adjusted so that P-polarized light reflected by reflective polarizing film 11 is incident on the reflective surface of reflector 14. That is, angles α, β, and γ can be collectively adjusted so that the P-polarized light emitted from display 10 follows an optical path that ultimately forms a real aerial image. Furthermore, angles α, β, and γ can be collectively adjusted so that the P-polarized light emitted from display 10 follows an optical path that efficiently forms a real aerial image (with high brightness efficiency). In addition, the position of origin D1, which is the other end of display 10, can be adjusted so that it is located on the +Z side of the extension of the reflective surface of reflecting member 2.

[0033] 1.2 Optical Path of Aerial Image Fig. 3 is a plan view showing an example of an optical path of an aerial image displayed by the aerial image display device according to the first embodiment. As shown in Fig. 3, the aerial image display device 1 displays a display image DI1 on the display surface of the display 10, thereby displaying an aerial image AI1 in the line of sight direction LOS.

[0034] The display 10 emits P-polarized light (hereinafter referred to as emitted light Pa1) from the display image DI1. The emitted light Pa1 is totally reflected by the reflective surface of the reflective polarizing film 11. The totally reflected light is referred to as reflected light Pb1. The reflected light Pb1 is reflected toward the reflector 14.

[0035] The reflected light Pb1 is retroreflected by the reflector 14 via the wave plate 13. The reflected light Pb1 passes through the wave plate 13 twice during the retroreflection process. The reflected light Pb1 that has passed through the wave plate 13 twice is referred to as reflected light Sc1. The phase of the reflected light Sc1 is shifted by π by retroreflection via the wave plate 13, and the reflected light becomes S-polarized light.

[0036] The reflected light Sc1 is retroreflected toward the beam splitter 12. The reflected light Sc1 is transmitted through the reflective polarizing film 11 and the beam splitter 12. The transmitted reflected light Sc1 is referred to as transmitted light Sd1.

[0037] The transmitted light Sd1 is reflected by the reflecting surface of the reflecting member 2. The reflected transmitted light Sd1 is referred to as reflected light Se1. The reflected light Se1 forms an aerial image AI1 and displays it in the line of sight LOS.

[0038] Here, there is a length H between the aerial image AI1 and the starting point A1.

[0039] 1.3 Effects of First Embodiment According to the aerial image display device 1 according to the first embodiment described above, it is possible to remove transmitted light from the display 10 while maintaining luminance efficiency.

[0040] As described above, in the aerial image display device 1 according to the first embodiment, the display 10 is configured to emit P-polarized light, and the reflective polarizing film 11 and the beam splitter 12 are configured to transmit S-polarized light and reflect P-polarized light. In this configuration, theoretically, 100% of the emitted light Pa1 becomes reflected light Pb1. In other words, because the emitted light Pa1 does not contain any components (S-polarized light) that would otherwise be transmitted through the beam splitter 12 and the reflective polarizing film 11, theoretically, 100% of the emitted light Pa1 becomes reflected light Pb1.

[0041] Next, the aerial image display device 1 includes a wave plate 13 between the reflective polarizing film 11 and the reflector 14, and the wave plate 13 is a λ / 4 wave plate. Therefore, when the reflector 14 performs total reflection, theoretically, 100% of the reflected light Pb1 becomes reflected light Sc1. Theoretically, 100% of the reflected light Sc1, which has become S-polarized, becomes transmitted light Sd1 and passes through the reflective polarizing film 11 and the beam splitter 12. In other words, because the reflected light Sc1 does not contain the component (P-polarized light) that is intended to be reflected by the beam splitter 12 and the reflective polarizing film 11, theoretically, 100% becomes transmitted light Sd1.

[0042] Furthermore, if the reflectance of the reflecting surface of the reflecting member 2 is 100%, theoretically 100% of the transmitted light Sd1 becomes reflected light Se1.

[0043] In this way, in the aerial image display device 1 according to the first embodiment, if a material with a reflectivity of 100% is used for the reflective surface of the reflective member 2, the aerial image AI1 can theoretically be formed with a brightness of 100%.

[0044] In the aerial image display device 1 according to the first embodiment, a polarized display is used for the display 10, thereby removing from the output light Pa1 the component (S-polarized light) that would otherwise be transmitted through the beam splitter 12 and the reflective polarizing film 11. Because the output light Pa1 does not contain any component that would otherwise be transmitted through the beam splitter 12 and the reflective polarizing film 11, there is no need to place a field of view control film or the like on the optical path to remove the transmitted light. By not placing a field of view control film or the like on the optical path, the aerial image display device 1 can maintain the brightness and image quality of the aerial image. In other words, the aerial image display device 1 according to the first embodiment can remove the transmitted light from the display 10 while maintaining brightness efficiency. Therefore, the aerial image display device 1 according to the first embodiment can improve user visibility.

[0045] Furthermore, by adjusting the angle γ, the aerial image display device 1 can prevent the light emitted from the display 10 from directly entering the reflector 14. Therefore, the aerial image display device 1 can be designed so that, in theory, stray light from the display 10 is not generated.

[0046] As described above, the aerial image display device 1 according to the first embodiment uses a reflector and a beam splitter, but does not use retro-transmitting optical elements such as MMAPs (Micro-Mirror Array Plates), etc. This makes it relatively easy to increase the size of the device, and therefore makes it possible to increase the size of the aerial image.

[0047] Furthermore, in the aerial image display device 1 according to the first embodiment, the position of the origin D1, which is the other end of the display 10, can be adjusted to the +Z side of the extension of the reflective surface of the reflective member 2. Therefore, the aerial image display device 1 can be used simply by placing it on the reflective surface of an existing reflective member 2. In other words, the optical system of the aerial image display system 5 can be completed on a tabletop.

[0048] 2. Second Embodiment Next, an aerial image display device 1 according to a second embodiment will be described. Hereinafter, the aerial image display system 5 and the aerial image display device 1 according to the second embodiment may be referred to as an aerial image display system 5A and an aerial image display device 1A, respectively, to distinguish them from the aerial image display system 5 and the aerial image display device 1 according to the first embodiment. The following mainly describes configurations that differ from the first embodiment.

[0049] 2.1 Configuration of the Aerial Image Display System The second embodiment differs from the first embodiment in that an aerial image can also be displayed on the −Z direction side of the reflecting surface of the reflecting member 2.

[0050] Specifically, the aerial image display system 5A according to the second embodiment differs from the aerial image display system 5 according to the first embodiment mainly in the structure of the display 10. Hereinafter, the display 10 according to the second embodiment may be referred to as a display 10A to distinguish it from the display 10 according to the first embodiment. In other respects, the second embodiment is substantially similar in structure to the first embodiment. The following description will mainly focus on the display 10A according to the second embodiment.

[0051] Fig. 4 is a plan view showing an example of an aerial image display device according to the second embodiment. Fig. 4 corresponds to Fig. 2 in the first embodiment. The aerial image display device 1A according to the second embodiment includes a display 10A, a reflective polarizing film 11, a beam splitter 12, a wave plate 13, and a reflector 14.

[0052] The display 10A is, for example, a polarized display. For example, P-polarized light is emitted from the display 10. The display 10A is disposed so that the display surface faces the inside of the aerial image display device 1.

[0053] The display 10A has a structure in which the display 10 in the first embodiment is extended toward the reflector 14 when viewed in the Y direction. In the display 10A, the portion that is extended more than the display 10 is hereinafter referred to as a display extension portion 102. Hereinafter, the portion of the display 10A that is similar to the display 10 is referred to as a display portion 101 in the second embodiment. That is, the display 10A has the display portion 101 and the display extension portion 102.

[0054] Here, the coordinate positions of the starting points C1 and D1 are the same as those in the first embodiment. Therefore, when viewed in the Y direction, the starting point C1 corresponds to the boundary between the display portion 101 and the display extension portion 102. When viewed in the Y direction, the starting point D1 corresponds to the end of the display 10A on the display portion 101 side.

[0055] For example, when viewed in the Y direction, the display 10A is disposed tilted in the positive direction (counterclockwise) with respect to the line segment connecting the starting point A1 and the starting point C1. When viewed in the Y direction, the angle that the display 10A forms with the wave plate 13 in the positive direction (counterclockwise) is referred to as an arbitrary angle γ, as in the first embodiment.

[0056] The size of the reflector 14 may be adjusted to accommodate the expansion of the display 10A compared to the display 10.

[0057] 2.2 Optical Path of Aerial Image Fig. 5 is a plan view showing an example of an optical path of an aerial image displayed by the aerial image display device according to the second embodiment. Fig. 5 corresponds to Fig. 3 in the first embodiment. As shown in Fig. 5, the aerial image display device 1A can display an aerial image AI2 in the line of sight LOS by displaying a display image DI2 on the display surface of the display 10A.

[0058] The aerial image AI2 has, for example, an aerial image AI21 which is a portion displayed on the +Z direction side of the reflecting surface, and an aerial image AI22 which is a portion displayed on the -Z direction side of the reflecting surface of the reflecting member 2.

[0059] The display 10A emits output light Pa22 from the display surface of the display extension portion 102, and emits output light Pa21 from the display surface of the display portion 101. The output light Pa21 follows the same optical path as the output light Pa1 of the first embodiment and forms an image in the same manner. The output light Pa21 ultimately forms an image on the +Z direction side of the reflecting surface of the reflecting member 2. That is, an aerial image AI21 is formed from the output light Pa21, and the aerial image AI21 is an aerial image similar to the aerial image AI1.

[0060] The light Pa22 emitted from the display extension 102 is P-polarized light. The light Pa22 is totally reflected by the reflective surface of the reflective polarizing film 11. The totally reflected light is called reflected light Pb2. The reflected light Pb2 is reflected in the direction of the reflector 14.

[0061] The reflected light Pb2 is retroreflected by the reflector 14 via the wave plate 13. The reflected light Pb2 passes through the wave plate 13 twice during the retroreflection process. The reflected light Pb2 that has passed through the wave plate 13 twice is referred to as reflected light Sc2. The phase of the reflected light Sc2 is shifted by π by retroreflection via the wave plate 13, and it becomes S-polarized light.

[0062] The reflected light Sc2 is retroreflected toward the beam splitter 12. The reflected light Sc2 is transmitted through the reflective polarizing film 11 and the beam splitter 12. The transmitted reflected light Sc2 is referred to as transmitted light Sd2.

[0063] The transmitted light Sd2 is reflected by the reflecting surface of the reflecting member 2. The reflected transmitted light Sd2 is referred to as reflected light Se2.

[0064] The position in the X direction at which the reflected light Se2 is reflected by the reflecting surface is on the −X side (a direction away from the origin A1) of the position at which the aerial image AI21 is formed. Therefore, the reflected light Se2 forms an image on the −Z side of the reflecting surface of the reflecting member 2. In other words, the reflected light Se2 forms an aerial image AI22, which is displayed in the line of sight LOS.

[0065] Here, there is a length H between the aerial image AI1 and the starting point A1.

[0066] 2.3 Effects of the Second Embodiment According to the aerial image display device 1A according to the second embodiment described above, an aerial image can be displayed also on the −Z direction side of the reflective surface of the reflecting member 2. As described above, in the aerial image display device 1A according to the second embodiment, the display 10A has a display extension section 102. The display extension section 102 is located closer to the reflector 14 (in the direction away from the starting point D1) than the line segment connecting the starting points A1 and C1.

[0067] Therefore, output light Pa22 emitted from the display surface of display extension unit 102 ultimately forms an aerial image AI22 on the −Z direction side of the reflective surface of reflecting member 2. This is because the position at which reflected light Se2 is reflected on the reflective surface of reflecting member 2 is on the −X side (a direction away from origin A1) of the position at which aerial image AI21 is formed. In this way, with the aerial image display device 1A according to the second embodiment, in addition to the aerial image on the +Z direction side of the reflective surface of reflecting member 2, an aerial image can also be displayed on the −Z direction side.

[0068] Furthermore, as in the first embodiment, the aerial image display device 1A according to the second embodiment uses a polarized display for the display 10A, eliminating the need to place a field of view control film or the like in the optical path to remove transmitted light from the display 10A. Because a field of view control film or the like is not placed in the optical path, the aerial image display device 1A can maintain the brightness and image quality of the aerial image. That is, the aerial image display device 1A can remove transmitted light from the display 10A while maintaining brightness efficiency. In the aerial image display device 1A, similar to the aerial image display device 1, if a material with a reflectivity of 100% is used for the reflective surface of the reflective member 2, the aerial image AI2 can theoretically be formed with 100% brightness. Therefore, the aerial image display device 1A according to the second embodiment can improve user visibility.

[0069] Furthermore, similarly to the first embodiment, the aerial image display device 1A can adjust the angle γ so that the light emitted from the display 10A does not directly enter the reflector 14. Therefore, the aerial image display device 1A can be designed so that, in theory, no stray light is generated from the display 10A.

[0070] Furthermore, similar to the first embodiment, the aerial image display device 1A uses a reflector and a beam splitter, but does not use a retro-transmitting optical element such as an MMAP, etc. Therefore, it is relatively easy to increase the size of the device, and it is possible to increase the size of the aerial image.

[0071] Furthermore, similar to the first embodiment, the aerial image display device 1A can adjust the position of the origin D1, which is the other end of the display 10A, to the +Z side of the extension of the reflective surface of the reflecting member 2. Therefore, the aerial image display device 1A can be used simply by placing it on the reflective surface of an existing reflecting member 2. In other words, the optical system of the aerial image display system 5A can be completed on a tabletop.

[0072] 3. Third Embodiment Next, an aerial image display device 1 according to a third embodiment will be described. Hereinafter, the aerial image display system 5 and the aerial image display device 1 according to the third embodiment may be referred to as an aerial image display system 5B and an aerial image display device 1B, respectively, to distinguish them from the aerial image display system 5 and the aerial image display device 1 according to the first embodiment. The following mainly describes configurations that differ from the first embodiment.

[0073] 3.1 Configuration of the Aerial Image Display System The third embodiment differs from the first embodiment in that a medium capable of displaying an image from a tablet terminal or the like is used as the reflective member 2 .

[0074] Specifically, the aerial image display system 5B according to the third embodiment differs from the aerial image display system 5 according to the first embodiment mainly in that a reflective member 2 is included in the aerial image display device 1B. Hereinafter, the reflective member 2 according to the third embodiment may be referred to as a reflective member 2B to distinguish it from the reflective member 2 according to the first embodiment. In other respects, the second embodiment is substantially similar in structure to the first embodiment. The following mainly describes the reflective member 2B according to the second embodiment.

[0075] Fig. 6 is a plan view showing an example of an aerial image display device according to the third embodiment. Fig. 6 corresponds to Fig. 2 in the first embodiment. The aerial image display device 1B according to the third embodiment includes a display 10, a reflective polarizing film 11, a beam splitter 12, a wave plate 13, a reflector 14, and a reflecting member 2B.

[0076] The reflective member 2B is a medium capable of displaying images on, for example, a tablet terminal, a smartphone, etc. The reflective member 2B has a display surface 2B1 configured to reflect incident light and display images.

[0077] The aerial image display device 1B can display a display image DI31 on the display surface 2B1 of the reflecting member 2B. That is, the aerial image display device 1B can display the display image DI31 in the line of sight LOS in addition to the aerial image formed by light from the display 10.

[0078] 3.2 Optical Path of Aerial Image Figure 7 is a plan view showing an example of an optical path of an aerial image displayed by the aerial image display device according to the third embodiment. Figure 7 corresponds to Figure 3 in the first embodiment. As shown in Figure 7, the aerial image display device 1B can display an aerial image AI3 in the line of sight LOS by displaying a display image DI3 on ​​the display surface of the display 10.

[0079] The imaging of the output light Pa1 emitted from the display surface of the display 10 is similar to that in the first embodiment. That is, an aerial image AI3 is formed from the output light Pa1, and the aerial image AI3 is an aerial image similar to the aerial image AI1.

[0080] The reflecting member 2B can display a display image DI31 on the display surface 2B1.

[0081] Therefore, the aerial image display device 1B can display the display image DI31 in the line of sight direction LOS in addition to the aerial image AI3.

[0082] 3.3 Effects of the Third Embodiment According to the aerial image display device 1B of the third embodiment described above, it is possible to produce an image representation that combines a vertical image representation with a horizontal image representation.

[0083] As described above, in the aerial image display device 1B according to the third embodiment, the reflecting member 2B is a medium capable of displaying an image of a tablet terminal or the like. The reflecting member 2B can display a display image DI31 on the display surface 2B1. That is, the aerial image display device 1B can display the display image DI31 in the line of sight LOS in addition to the aerial image AI3 formed by light from the display 10. In this way, the aerial image display device 1B can express a wider range of images by combining the aerial image AI3, which is an image in the vertical direction (YZ directions), with the display image DI31, which is an image in the horizontal direction (XY directions).

[0084] Furthermore, a glossy film or the like may be attached to display surface 2B1 of reflective member 2B to improve gloss and reduce roughness. By improving gloss and reducing roughness, reflective member 2B can display aerial image AI3 with higher brightness and better image quality.

[0085] Furthermore, as in the first embodiment, the aerial image display device 1B according to the third embodiment uses a polarized display for the display 10, thereby eliminating the need to place a field of view control film or the like on the optical path to remove transmitted light from the display 10. By not placing a field of view control film or the like on the optical path, the aerial image display device 1B can maintain the brightness and image quality of the aerial image. In other words, the aerial image display device 1B can remove transmitted light from the display 10 while maintaining brightness efficiency. Therefore, the aerial image display device 1B according to the third embodiment can improve visibility for the user.

[0086] Furthermore, similarly to the first embodiment, the aerial image display device 1B can adjust the angle γ so that the light emitted from the display 10 does not directly enter the reflector 14. Therefore, the aerial image display device 1B can be designed so that, in theory, stray light from the display 10 is not generated.

[0087] Furthermore, similar to the first embodiment, the aerial image display device 1B uses a reflector and a beam splitter, but does not use a retrotransmissive optical element such as an MMAP, etc. Therefore, it is relatively easy to increase the size of the device, and it is possible to increase the size of the aerial image.

[0088] Furthermore, similar to the first embodiment, the aerial image display device 1B can adjust the position of the origin D1, which is the other end of the display 10, to the +Z side of the extension of the display surface 2B1 of the reflecting member 2B. Therefore, the aerial image display device 1B can be used simply by placing it on the display surface 2B1 of an existing reflecting member 2B. In other words, the optical system of the aerial image display system 5B can be completed on a tabletop (on a tablet terminal or a smartphone).

[0089] 4. Fourth Embodiment Next, an aerial image display device 1 according to a fourth embodiment will be described. Hereinafter, the aerial image display system 5 and the aerial image display device 1 according to the fourth embodiment may be referred to as an aerial image display system 5C and an aerial image display device 1C, respectively, to distinguish them from the aerial image display system 5 and the aerial image display device 1 according to the first embodiment. The following mainly describes configurations that differ from the first embodiment.

[0090] 4.1 Configuration of Aerial Image Display System The fourth embodiment differs from the first embodiment in that the viewing area of ​​the aerial image can be expanded in the horizontal direction.

[0091] Specifically, the aerial image display device 1C according to the fourth embodiment differs from the aerial image display device 1 according to the first embodiment mainly in that it further includes mirrors 16C and 17C. In other respects, the fourth embodiment is substantially similar to the first embodiment. The following mainly describes the structures of mirrors 16C and 17C.

[0092] Fig. 8 is a plan view showing an example of an aerial image display device according to a fourth embodiment. Fig. 8 corresponds to Fig. 2 of the first embodiment as viewed in the -Z direction (XY plan view as viewed from the +Z side). The aerial image display device 1C according to the fourth embodiment includes a display 10, a reflective polarizing film 11, a beam splitter 12, a wave plate 13, a reflector 14, a mirror 16C, and a mirror 17C.

[0093] The mirror 16C is provided, for example, in the shape of a plate extending along the ZX plane. The mirror 16C contacts one end of the beam splitter 12 and one end of the reflector 14 when viewed in the −Z direction (when viewed in the XY plane from the +Z side).

[0094] The mirror 17C is provided, for example, in the shape of a plate extending along the ZX plane. When viewed in the −Z direction, the mirror 17C contacts the other ends of the beam splitter 12 and the reflector 14 (ends opposite to the side where the mirror 16C is provided).

[0095] 4.2 Optical Path of Aerial Image Figure 9 is a plan view showing an example of an optical path of an aerial image displayed by the aerial image display device according to the fourth embodiment. Figure 5 corresponds to the state of Figure 3 in the first embodiment when viewed in the -Z direction. As shown in Figure 9, the aerial image display device 1C can display an aerial image AI4 in the line of sight direction LOS by displaying a display image DI4 on the display surface of the display 10.

[0096] Of the light emitted from display 10, light that forms an image by following an optical path that does not pass through mirror 16C or mirror 17C is called emitted light Pa41. Of the light emitted from display 10, light that forms an image by following an optical path that passes through mirror 16C or mirror 17C is called emitted light Pa42. Emitted light Pa41 follows the same optical path as emitted light Pa1 in the first embodiment and forms an image in the same way. Emitted light Pa41 viewed in the -Z direction follows the following optical path.

[0097] The output light Pa41 emitted from the display 10 is P-polarized light. The output light Pa41 is totally reflected by the reflective surface of the reflective polarizing film 11 on the beam splitter 12. The point at which the output light Pa41 is totally reflected is called the reflection-transmission point 12C1. The totally reflected light is called reflected light Pb41. The reflected light Pb41 is reflected in the direction of the reflector 14.

[0098] The reflected light Pb41 is retroreflected by the reflector 14 via the wave plate 13. The point at which the reflected light Pb41 is retroreflected on the reflector 14 is referred to as the reflector reflection point 14C1. The reflected light Pb41 passes through the wave plate 13 twice during the retroreflection process. The reflected light Pb41 that has passed through the wave plate 13 twice is referred to as the reflected light Sc41. The phase of the reflected light Sc41 is shifted by π by retroreflection via the wave plate 13, and it becomes S-polarized light.

[0099] The reflected light Sc41 is retroreflected toward the beam splitter 12. The reflected light Sc41 passes through the reflective polarizing film 11 and the beam splitter 12. The reflected light Sc41 passes through the reflection-transmission point 12C1. The transmitted reflected light Sc41 is referred to as transmitted light Sd41.

[0100] The transmitted light Sd41 is reflected by the reflecting surface of the reflecting member 2. The point at which the transmitted light Sd41 is reflected on the reflecting member 2 is referred to as the reflecting member reflection point 2C1. The reflected transmitted light Sd41 is referred to as the reflected light Se41. The reflected light Se41 forms an aerial image AI4 and displays it in the line of sight. The viewing zone of the aerial image AI4 formed by the reflected light Se41 is restricted by the width in the Y direction of, for example, the beam splitter 12.

[0101] Next, the emitted light Pa42 seen in the −Z direction follows the following optical path.

[0102] The outgoing light Pa42 emitted from the display 10 is P-polarized light. The outgoing light Pa42 is totally reflected, for example, by the reflecting surface of mirror 16C. The totally reflected outgoing light Pa42 is then totally reflected by the reflecting surface of the reflective polarizing film 11 on the beam splitter 12. The point at which the outgoing light Pa42 is totally reflected is called the reflection-transmission point 12C2. The totally reflected light is called reflected light Pb42. The reflected light Pb42 is reflected in the direction of the reflector 14.

[0103] The reflected light Pb42 is retroreflected by the reflector 14 via the wave plate 13. The point at which the reflected light Pb42 is retroreflected on the reflector 14 is referred to as the reflector reflection point 14C2. The reflected light Pb42 passes through the wave plate 13 twice during the retroreflection process. The reflected light Pb42 that has passed through the wave plate 13 twice is referred to as the reflected light Sc42. The phase of the reflected light Sc42 is shifted by π by retroreflection via the wave plate 13, and it becomes S-polarized light.

[0104] The reflected light Sc42 is retroreflected toward the beam splitter 12. The reflected light Sc42 passes through the reflective polarizing film 11 and the beam splitter 12. The reflected light Sc42 passes through the reflection-transmission point 12C2. The transmitted reflected light Sc42 is referred to as transmitted light Sd42.

[0105] The transmitted light Sd42 is totally reflected by the reflecting surface of mirror 16C. The totally reflected transmitted light Sd42 is reflected by the reflecting surface of reflecting member 2. The point at which the transmitted light Sd42 is reflected on reflecting member 2 is referred to as reflecting member reflection point 2C2. The reflected transmitted light Sd42 is referred to as reflected light Se42. The reflected light Se42 forms an aerial image AI4 and displays it in the line of sight. The viewing zone of the aerial image AI4 formed by the reflected light Se42 is expanded by mirror 16C. As described above, the emitted light Pa42 that is emitted from display 10 in the Y direction and extends beyond beam splitter 12 can also be used to form the aerial image AI4, thereby expanding the viewing zone of the aerial image AI4.

[0106] The case where the emitted light Pa42 is totally reflected by mirror 16C has been described above, but the same applies to the case where the emitted light Pa42 is totally reflected by mirror 17C. The viewing zone of the aerial image AI4 is expanded by the amount that the reflected light Se42 can be imaged via mirror 16C and mirror 17C.

[0107] 4.3 Effects of Fourth Embodiment According to the aerial image display device 1C according to the second embodiment described above, the viewing zone of the aerial image can be expanded in the horizontal direction.

[0108] If the aerial image display device 1C does not have mirrors 16C and 17C, the horizontal viewing area (X and Y directions) in which the aerial image can be observed without loss is limited by the widths of the reflector, beam splitter, and reflective member in the Y direction. For this reason, for example, in the case of a small aerial image display device, the viewing area may become narrow.

[0109] In contrast, the aerial image display device 1C according to the fourth embodiment further includes mirrors 16C and 17C. By including mirrors 16C and 17C, the aerial image display device 1C can utilize light (emitted light Pa42) that is emitted in the Y direction from the display 10 and cannot be directly received by the reflective polarizing film 11 to form the aerial image AI4.

[0110] That is, in the aerial image display device 1C, the emitted light Pa42 is totally reflected by mirror 16C or mirror 17C, allowing the emitted light Pa42 to be received by the reflective polarizing film 11. By receiving the emitted light Pa42, the reflective polarizing film 11 can use the emitted light Pa42 to form the aerial image AI4, thereby expanding the viewing zone of the aerial image AI4. This has the same effect as expanding the reflective polarizing film 11, etc. in the Y direction.

[0111] In this way, by having mirrors 16C and 17C, aerial image display device 1C can expand the viewing area of ​​the aerial image in the horizontal direction without changing the size of beam splitter 12 or the like.

[0112] Furthermore, as with the first embodiment, the aerial image display device 1C according to the fourth embodiment uses a polarized display for the display 10, eliminating the need to place a field of view control film or the like in the optical path to remove transmitted light from the display 10. Because a field of view control film or the like is not placed in the optical path, the aerial image display device 1C can maintain the brightness and image quality of the aerial image. That is, the aerial image display device 1C can remove transmitted light from the display 10 while maintaining brightness efficiency. In the aerial image display device 1C, similar to the aerial image display device 1, if a material with a reflectivity of 100% is used for the reflective surface of the reflective member 2, the aerial image AI4 can theoretically be formed with 100% brightness. Therefore, the aerial image display device 1C according to the fourth embodiment can improve user visibility.

[0113] Furthermore, similar to the first embodiment, the aerial image display device 1C can adjust the angle γ so that light emitted from the display 10 does not directly enter the reflector 14. Therefore, the aerial image display device 1C can be designed so that, in theory, stray light from the display 10 is not generated.

[0114] Furthermore, as in the first embodiment, the aerial image display device 1C uses a reflector and a beam splitter, but does not use a retro-transmitting optical element such as an MMAP, etc. Therefore, it is relatively easy to increase the size of the device, and it is possible to increase the size of the aerial image.

[0115] Furthermore, similar to the first embodiment, the aerial image display device 1C can adjust the position of the origin D1, which is the other end of the display 10, to the +Z side of the extension of the reflective surface of the reflecting member 2. Therefore, the aerial image display device 1C can be used simply by placing it on the reflective surface of an existing reflecting member 2. In other words, the optical system of the aerial image display system 5 can be completed on a tabletop.

[0116] 5. Modifications, etc. Various modifications can be applied to the first, second, third, and fourth embodiments described above.

[0117] In the above-described embodiment, the displays 10 and 10A may be tilted approximately 90 degrees in the positive direction (counterclockwise) with respect to the line segment connecting the origin A1 and the origin C1 when viewed in the Y direction. Furthermore, for example, the displays 10 and 10A may be tilted by more or less than 90 degrees with respect to the line segment connecting the origin A1 and the origin C1. In this case, the image displayed on the display surface of the display is tilted, thereby allowing the aerial image to be displayed at an angle. Furthermore, for example, the brightness efficiency can be increased by arranging the front of the display surface of the displays 10 and 10A so that it faces the beam splitter 12.

[0118] In the above-described embodiment, a case has been described in which flat displays are used for the displays 10 and 10A, but this is not limiting. For example, a stereoscopic aerial image may be displayed by using a stereoscopic display for the displays 10 and 10A.

[0119] Furthermore, in the above-described embodiment, the case where the plane parallel to the reflective surface of the reflective member 2 is the XY plane has been described, but this is not limited to this. That is, the reflective surface of the reflective member 2 is not limited to a floor, a desk, etc. For example, a wall or a ceiling may be used as the reflective surface of the reflective member 2. The reflective surface of the reflective member 2 may be disposed in any orientation.

[0120] Furthermore, in the above-described embodiment, the case where the user's line of sight LOS is a direction obtained by combining the +X direction and the −Z direction has been described, but this is not limited thereto. For example, the user's line of sight LOS may be a direction perpendicular to the reflector 14 when viewed in the Y direction. The position and angle of the reflector 14 may be adjusted so that the user's line of sight LOS and the orientation of the reflector 14 are perpendicular to each other. For example, when the user's line of sight LOS and the orientation of the reflector 14 are perpendicular to each other, the luminance efficiency can be increased. Furthermore, when a prism-type reflector is used for the reflector 14, the reflectance increases when the angle of incidence is 0 degrees. Furthermore, when a bead-type reflector is used for the reflector 14, this is an effective countermeasure against brightness reduction when the user's line of sight LOS is moved to the upper limit in the Z direction.

[0121] Furthermore, in the above-described embodiment, a case where P-polarized light is emitted from the display has been described, but this is not limiting. For example, the light emitted from the display may be S-polarized or unpolarized. When the light emitted from the display is S-polarized, for example, a reflective polarizing film 11 and a beam splitter 12 that reflect S-polarized light and transmit P-polarized light are provided. When the light emitted from the display is unpolarized, for example, an absorbing polarizing plate that selectively transmits light of the polarization axis (e.g., P-polarized light) reflected by the reflective polarizing film 11 and the beam splitter is provided between the display and the beam splitter.

[0122] Furthermore, in the fourth embodiment described above, the mirrors 16C and 17C extend along the ZX plane, but this is not limiting. For example, the mirrors 16C and 17C may be tilted in the Y direction at an angle sufficient to reflect the emitted light Pa42. The aerial image display device 1C can obtain the widest viewing zone by installing the mirrors 16C and 17C perpendicular to the reflective surface of the reflective member 2.

[0123] The present invention is not limited to the above-described embodiments, and various modifications can be made in the implementation stage without departing from the spirit of the invention. Furthermore, the embodiments may be implemented in appropriate combinations, in which case the combined effects can be obtained. Furthermore, the above-described embodiments include various inventions, and various inventions can be extracted by combining selected elements from the disclosed elements. For example, if the problem can be solved and the desired effect can be obtained even if some elements are deleted from all elements shown in the embodiments, the configuration from which these elements are deleted can be extracted as an invention.

[0124] DESCRIPTION OF SYMBOLS 1, 1A, 1B, 1C...Aerial image display device 2, 2B...Reflective member 2B1...Display surface 5, 5A, 5B, 5C...Aerial image display system 9...Control device 10, 10A...Display 11...Reflective polarizing film 12...Beam splitter 13...Wave plate 14...Reflector 16C, 17C...Mirror 90...Processor 91...ROM 92...RAM 93...Storage 94...Interface 101...Display portion 102...Display extension A1, B1, C1, D1...Origin AI...Aerial image DI...Display image Pa...Emitted light Pb, Sc, Se...Reflected light Sd...Transmitted light

Claims

1. An aerial image display device arranged on a first reflecting surface of a reflecting member, comprising: a display; a pair of a reflective polarizing film and a beam splitter arranged at an angle such that a first outgoing light can be received from the display; a reflector arranged at an angle such that the first reflected light can be received from the pair of the reflective polarizing film and the beam splitter; and a wave plate arranged between the reflector and the beam splitter, wherein the display emits the first outgoing light which is a first linearly polarized light; the pair of the reflective polarizing film and the beam splitter receives the first outgoing light and reflects it as the first reflected light; the pair of the reflector and the wave plate receives the first reflected light which is the first linearly polarized light and retroreflects it as a first retroreflected light which is a second linearly polarized light orthogonal to the first linearly polarized light; and the pair of the reflective polarizing film and the beam splitter transmits the first retroreflected light as a first transmitted light; the first reflecting surface receives the first transmitted light and reflects it as a first imaging light to display a first aerial image.

2. An aerial image display device as described in claim 1, wherein the beam splitter intersects with the first reflecting surface or an extension of the first reflecting surface at a first starting point on the display side, the reflector intersects with the beam splitter or an extension of the beam splitter at a second starting point opposite the first starting point, and the display intersects with the reflector or an extension of the reflector at a third starting point opposite the second starting point.

3. The aerial image display device according to claim 1, wherein each of the reflective polarizing film and the beam splitter is configured to reflect the first linearly polarized light and transmit the second linearly polarized light, and the wave plate is a λ / 4 wave plate.

4. An aerial image display device as described in claim 2, wherein the display further has a first display portion extended in the direction of the reflector, the first display portion emitting a second outgoing light which is the first linearly polarized light, the pair of the reflective polarizing film and the beam splitter receiving the second outgoing light and reflecting it as a second reflected light, the pair of the reflector and the wave plate receiving the second reflected light which is the first linearly polarized light and reflecting it back as a second retroreflected light which is the second linearly polarized light, the pair of the reflective polarizing film and the beam splitter transmitting the second retroreflected light as a second transmitted light, the first reflecting surface receiving the second transmitted light and reflecting it as a second imaging light to display a second aerial image, and the second aerial image being displayed on the opposite side of the first reflecting surface from the first aerial image.

5. An aerial image display device according to claim 1, wherein the reflective member is a medium capable of displaying a first image on the first reflective surface.

6. An aerial image display device as described in claim 1, further comprising a first mirror extending in a first direction from the display toward the beam splitter and facing a second direction intersecting the first direction, wherein the display emits a third outgoing light which is the first linearly polarized light, the third outgoing light being reflected by the first mirror, the set of the reflective polarizing film and the beam splitter receiving the third outgoing light reflected by the first mirror and reflecting it as a third reflected light, the set of the reflector and the wave plate receiving the third reflected light which is the first linearly polarized light and reflecting it back as a third retroreflected light which is the second linearly polarized light, the set of the reflective polarizing film and the beam splitter transmitting the third retroreflected light as a third transmitted light, the third transmitted light being reflected by the first mirror, and the first reflective surface receiving the third transmitted light reflected by the first mirror and reflecting it as a third imaging light to display a third aerial image.

7. An aerial image display device according to claim 6, wherein the third outgoing light is emitted at a greater angle in the second direction than the first outgoing light.

8. An aerial image display device as described in claim 6, further comprising: a second mirror which, together with the first mirror, sandwiches the beam splitter and the reflector; wherein the display emits a fourth outgoing light which is the first linearly polarized light, the fourth outgoing light being reflected by the second mirror; the set of the reflective polarizing film and the beam splitter receives the fourth outgoing light reflected by the second mirror and reflects it as a fourth reflected light; the set of the reflector and the wave plate receives the fourth reflected light which is the first linearly polarized light and reflects it back as a fourth retroreflected light which is the second linearly polarized light; the set of the reflective polarizing film and the beam splitter transmits the fourth retroreflected light as a fourth transmitted light, the fourth transmitted light being reflected by the second mirror; and the first reflective surface receives the fourth transmitted light reflected by the second mirror and reflects it as a fourth imaging light to display a fourth aerial image.

Images