Aerial image display device

Abstract

According to an embodiment, this aerial image display device comprises a display that displays an object, a beam splitter, and a retroreflective material. The beam splitter is provided at a first angle with respect to a reference plane, reflects a part of emitted light from the display, and transmits a part of the emitted light. The retroreflective material retroreflects the transmitted or reflected emitted light to obtain retroreflected light. The retroreflected light reflected by or transmitted through the beam splitter is guided to a reflection plane, which is provided to be inclined with respect to the reference plane at a second angle in a direction facing a viewer, to form an aerial image derived from the object.

Description

Aerial image display device

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

[0002] An aerial image display technology has been proposed that displays an aerial image as if an object actually exists in empty space. For example, in an aerial image optical system using a recursive transmission element such as MMAP (micro mirror array plates) or a retroreflective element, a portable tabletop aerial image optical system can be realized by combining it with a reflective surface.

[0003] Hoshi Saisui, Makiguchi Takamune, Sano Ayaka, Chige Hiroshi, Mochizuki Takayoshi, "Optical System for Displaying Upright Aerial Image on Touch Panel and Initial Study on Its Interaction"

[0004] In this type of optical system, a technique capable of displaying an aerial image upright with respect to a reflection surface is known (Non-Patent Document 1). However, when the size of the aerial image is increased, the viewing range shifts upward in the vertical direction. For this reason, it has been impossible to adjust the viewing range according to the intended use.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a technique capable of adjusting the viewing range regardless of the size of an aerial image.

[0006] According to an embodiment, the aerial image display device includes a display that displays an object, a beam splitter having reflective polarization characteristics, and a retroreflective material including a wave plate. The beam splitter having reflective polarization characteristics is provided at a first angle with respect to a reference plane, and partially reflects and partially transmits the light emitted from the display. The retroreflective material including the wave plate changes the polarization state of one of the emitted light beams and retroreflectively reflects the light. Then, the retrotransmitted light is guided to a reflection surface provided inclined with respect to the reference plane at a second angle in a direction facing the observer, so that an aerial image derived from the object is formed.

[0007] According to an embodiment, in a tabletop aerial image display device, the object is to provide a technique capable of adjusting the viewing range regardless of the size of the aerial image.

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

[0009] Several embodiments will be described below with reference to the drawings. In the following description, components having the same function and configuration will be denoted by the same reference numerals.

[0010] [First Embodiment] Figure 1 is a block diagram showing the overall configuration of an aerial image display system according to the first embodiment. As shown in Figure 1, the aerial image display system 5 includes an aerial image display device 1, a reflective member 2, and a control device 9 according to the first embodiment. 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 above the reflective member 2. Details of the configurations of the aerial image display device 1 and the reflective member 2 will be described later.

[0011] The control device 9 controls the aerial image display device 1. The control device 9 includes a processor 90, ROM (Read Only Memory) 91, RAM (Random Access Memory) 92, storage 93, and interface 94.

[0012] 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). Multiple processors 90 may be provided within the control device 9.

[0013] ROM91 is a non-volatile semiconductor memory such as EEPROM®. ROM91 stores programs and control data for controlling the aerial image display device 1.

[0014] RAM 92 is a volatile semiconductor memory such as DRAM (Dynamic RAM) or SRAM (Static RAM). RAM 92 is used as a workspace for the processor 90.

[0015] The storage device 93 is a non-volatile storage device such as an HDD (Hard Disk Drive), SSD (Solid State), or memory card. The storage device 93 stores various types of information and data. Program and control data may also be stored in the storage device 93. For example, the storage device 93 stores video data that is projected onto the aerial image display device 1.

[0016] Interface 94 includes various connectors, various ports, signal processing circuits, and communication modules. Interface 94 connects the control device 9 to the aerial image display device 1. Interface 94 is responsible for input and output of information and data, various processing of information and data, and various controls for acquiring information and data. Interface 94 receives input from the user of the aerial image display device 1 via input devices (not shown) such as a touch panel, keyboard, mouse, operation buttons, and microphone. Interface 94 provides various information and data to the user of the aerial image display device 1 via output devices (not shown) such as a display and speaker. Interface 94 can transfer information and data between the aerial image display device 1 and the control device 9 via wireless or wired network communication. Interface 94 sends various control signals from the processor 90 to the aerial image display device 1. Interface 94 sends various control signals from the aerial image display device 1 to the processor 90.

[0017] 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 reflective member 2 based on a display image shown on the display surface of a display. The real aerial image displayed by the aerial image display device 1 is displayed in a direction substantially perpendicular to the reflective surface of the reflective member 2. For the sake of explanation, the plane parallel to the reflective surface of the reflective member 2 equipped with the aerial image display system 5 will be referred to as the XY plane. The plane parallel to the display surface of the real aerial image will be referred to as the YZ plane. The direction in which the XY plane and the YZ plane intersect will be the Y direction. The direction perpendicular to the Y direction within the XY plane will be the X direction. The direction perpendicular to the Y direction within the YZ plane will be the Z direction. The user's line of sight direction LOS will be 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 direction LOS (i.e., the direction approaching the user) will be assumed to coincide with the direction obtained by combining the -X direction and the +Z direction.

[0018] Figure 2 is a plan view showing an example of an aerial image display device according to the first embodiment. Figure 2 shows the planar positional relationship between the reflective member 2 and the aerial image display device 1 when viewed in the Y direction (in a ZX plan view seen from the -Y side).

[0019] In Figure 2, a beam splitter 12 is provided at an angle α with respect to a reference plane shown by a dotted line. A retroreflective material 14 is provided so as to intersect the beam splitter 12 at the starting point B1. Here, the angle between the flat beam splitter 12 and the retroreflective material 14 is denoted as β. A quarter-wave plate 13 is provided on the surface of the retroreflective material 14 facing the beam splitter 12. In addition, a reflective polarizing film 11 is attached to the surface of the beam splitter 12 facing the quarter-wave plate 13.

[0020] A display 10 for displaying an object is provided at a second starting point C1, which is on the opposite side of the retroreflective material 14 from the starting point B1. The display 10 is positioned so that its display surface faces inward from the aerial image display device 1. Viewed in the Y direction, one end of the display 10 is positioned to intersect with the other end of the retroreflective material 14, that is, the starting point C1, which is the end opposite to the starting point B1. The other end of the display 10 (the end opposite to the starting point C1) is referred to as the third starting point D1. Let γ be the angle between the retroreflective material 14 and the display 10.

[0021] Furthermore, a reflective member 2 is provided at a position that forms an angle δ with respect to the reference plane. That is, the reflective member 2 is provided inclined at an angle δ with respect to the reference plane in a direction directly facing the observer. The reflective member 2 has a reflective surface configured to reflect incident light. The reflective surface of the reflective member 2 includes mirrors, glossy table surfaces, etc. The reflective member 2 also includes, for example, a half-mirror or glossy film placed on a non-glossy surface. The reflective member 2 also includes, for example, a glossy agent coated on a non-glossy surface. In the optical system with the above configuration, an aerial image AI1 originating from an object displayed on the display 10 is formed by guiding the light transmitted through the reflective polarizing film 11.

[0022] Let H be the length between starting point A1 and starting point C1. The display 10 is positioned, for example, at a positive (counterclockwise) angle with respect to the line segment connecting starting point A1 and starting point C1 when viewed in the Y direction. The angle γ is the angle that the display 10 makes with respect to the waveplate 13 in the positive (counterclockwise) direction when viewed in the Y direction.

[0023] The beam splitter 12 is, for example, a reflective polarizing film. The reflective polarizing film transmits light of the same polarization state and reflects light of the same polarization state. Hereinafter, the polarization state of light transmitted through the beam splitter 12 will be called S-polarization, and the polarization state of light reflected by the beam splitter 12 will be called P-polarization. The reflective polarizing film 11 reflects 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 to face inward towards the aerial image display device 1.

[0024] The retroreflective material 14 has a reflective surface configured to retroreflectively reflect incident light. The reflective surface of the retroreflective material 14 is positioned to face inward towards the aerial image display device 1. The retroreflective material 14 is positioned inside the aerial image display device 1 at an arbitrary angle β in the positive direction (counterclockwise) relative 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 retroreflective material 14 intersects at the starting point B1.

[0025] The orientation of the display 10 and the beam splitter 12 is adjusted so that the P-polarized light emitted from the display 10 is incident on the reflective surface of the reflective polarizing film 11. Similarly, the orientation of the beam splitter 12 and the retroreflective material 14 is adjusted so that the P-polarized light reflected by the reflective polarizing film 11 is incident on the reflective surface of the retroreflective material 14. In other words, angles α, β, and γ can be comprehensively adjusted so that the P-polarized light emitted from the display 10 follows an optical path that ultimately allows it to form a real aerial image. Furthermore, angles α, β, and γ can be comprehensively adjusted so that the P-polarized light emitted from the display 10 follows an optical path that allows it to efficiently (with high brightness efficiency) form a real aerial image. In addition, the position of the starting point D1, which is the other end of the display 10, can be adjusted so that it is located +Z side of the lower end of the reflective surface of the reflective member 2.

[0026] The waveplate 13 is, for example, a λ / 4 waveplate. The waveplate 13 is configured to emit light with a phase shift of π / 4 between the P-polarized and S-polarized light in the incident light. The waveplate 13 is attached to the reflective surface of the retroreflective material 14. That is, the waveplate 13 is positioned to face the reflective surface of the reflective polarizing film 11.

[0027] The display 10 is, for example, a polarizing display having specific polarization characteristics. Light that is, for example, P-polarized is emitted from the display 10. The display 10 is positioned so that its display surface faces inward towards the aerial image display device 1. Viewed in the Y direction, one end of the display 10 is positioned to intersect with the starting point C1 of the retroreflective material 14. Alternatively, instead of a polarizing display, an optical system may be used by combining a display that emits normal light with a polarizer that absorbs and polarizes the light emitted from the display.

[0028] Figure 3 is a plan view showing an example of the imaging optical path of an aerial image displayed by the aerial image display device according to the first embodiment. As shown in Figure 3, the aerial image display device 1 can display the aerial image AI1 in the line of sight LOS by displaying the display image DI1 on the display surface of the display 10.

[0029] 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 in the direction of the retroreflective material 14.

[0030] The reflected light Pb1 is retroreflective by the retroreflective material 14 via the waveplate 13. The reflected light Pb1 passes through the waveplate 13 twice during the retroreflection process. The reflected light Pb1 that has passed through the waveplate 13 twice is called reflected light Sc1. The phase of the reflected light Sc1 is shifted by π due to retroreflection via the waveplate 13, and it becomes S-polarized light.

[0031] The reflected light Sc1 is retroreflected in the direction of the beam splitter 12. The reflected light Sc1 passes through the reflective polarizing film 11 and the beam splitter 12. The transmitted reflected light Sc1 is referred to as transmitted light Sd1.

[0032] The transmitted light Sd1 is reflected by the reflective surface of the reflective member 2. The reflected transmitted light Sd1 is called reflected light Se1. The reflected light Se1 forms an aerial image AI1 and displays it in the line of sight LOS.

[0033] Figures 4 and 5 are diagrams illustrating the optical path in the aerial image display device of the embodiment. Let r be the inclination of the reflective surface 2, b be the inclination of the beam splitter, B be the size of the beam splitter, D be the size of the display, L be the projection distance of the aerial image AI1, and C be the horizontal distance from the aerial image to the viewpoint. The calculation formulas that hold between each parameter are shown below.

[0034]

[0035] Furthermore, the aerial image display device 1 according to the first embodiment uses retroreflective material and a beam splitter, and does not use retrotransmitting optical elements such as MMAP (Micro-Mirror Array Plates). For this reason, it is relatively easy to enlarge the device, and it is possible to enlarge the aerial image.

[0036] As described above, in the first embodiment, the reflective surface 2 that displays the aerial image is tilted, and the position angle of the beam splitter 12 and the display 10 is adjusted. By tilting the reflective surface 2 in a direction that faces the observer side of the aerial image, the range of adjustment for each parameter can be increased. Therefore, by optimally setting the parameters related to the optical system, the field of view shift when magnifying the aerial image can be suppressed. Accordingly, according to the first embodiment, an aerial image display device that can adjust the field of view regardless of the size of the aerial image can be provided, thereby making it possible to adjust the field of view according to the application.

[0037] [Second Embodiment] Figure 6 is a plan view showing an example of an aerial image display device according to the second embodiment. Figure 2 corresponds to Figure 2 in the first embodiment. The aerial image display device 1A according to the second embodiment comprises a display 10A, a reflective polarizing film 11, a beam splitter 12, a waveplate 13, and a retroreflective material 14.

[0038] Display 10A is, for example, a polarizing display. Display 10 emits, for example, P-polarized light. Display 10A is positioned so that its display surface faces inward towards the aerial image display device 1.

[0039] In the Y-direction, the display 10A has a structure in which the display 10 in the first embodiment is extended toward the retroreflective material 14. In the display 10A, the portion that is extended beyond the display 10 will be referred to as the display extension portion 102 below. Here, in the display 10A, the portion that is the same as the display 10 will be referred to as the display portion 101 in the second embodiment. That is, the display 10A has a display portion 101 and a display extension portion 102.

[0040] Here, the coordinate positions of starting point C1 and starting point D1 are the same as in the first embodiment. Therefore, looking in the Y direction, starting point C1 corresponds to the boundary between the display portion 101 and the display extension portion 102. Looking in the Y direction, starting point D1 corresponds to the end of the display 10A on the display portion 101 side.

[0041] The display 10A is positioned, for example, at a positive (counterclockwise) angle with respect to the line segment connecting the starting point A1 and the starting point C1 when viewed in the Y direction. Let γ be the angle that the display 10A makes with respect to the waveplate 13 in the positive (counterclockwise) direction when viewed in the Y direction.

[0042] Since the display 10A is larger than the display 10, the size of the retroreflective material 14 may be adjusted.

[0043] Figure 5 is a plan view showing an example of the imaging optical path of an aerial image displayed by the aerial image display device according to the second embodiment. As shown in Figure 5, the aerial image display device 1A can display the aerial image AI2 in the line of sight LOS by displaying the display image DI2 on the display surface of the display 10A.

[0044] The aerial image AI2 includes, for example, an aerial image AI21 which is the portion displayed on the +Z direction side of the reflective surface, and an aerial image AI22 which is the portion displayed on the -Z direction side of the reflective surface of the reflective member 2.

[0045] 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 finally forms an image on the +Z direction side relative to the reflective surface of the reflective member 2. That is, an aerial image AI21 is formed from the output light Pa21, and the aerial image AI21 is the same type of aerial image as the aerial image AI1.

[0046] The output light Pa22 output from the display extension portion 102 is P-polarized light. The output light Pa22 is totally reflected by the reflective surface of the reflective polarizing film 11. The totally reflected light is referred to as reflected light Pb2. The reflected light Pb2 is reflected toward the retroreflector 14.

[0047] The reflected light Pb2 is retroreflected by the retroreflector 14 via the wave plate 13. The reflected light Pb2 transmits through the wave plate 13 twice during the retroreflection process. The reflected light Pb2 that has transmitted through the wave plate 13 twice is referred to as reflected light Sc2. The reflected light Sc2 becomes S-polarized light through retroreflection via the wave plate 13.

[0048] The reflected light Sc2 is retroreflected toward the beam splitter 12. The reflected light Sc2 transmits through the reflective polarizing film 11 and the beam splitter 12. The transmitted reflected light Sc2 is referred to as transmitted light Sd2.

[0049] The transmitted light Sd2 is reflected by the reflective surface of the reflective member 2. The reflected transmitted light Sd2 is referred to as reflected light Se2.

[0050] The position in the X direction where the reflected light Se2 reflects on the reflective surface is on the -X side (the direction away from the starting point A1) relative to the position where the aerial image AI21 is formed. For this reason, the reflected light Se2 forms an image on the -Z direction side relative to the reflective surface of the reflective member 2. That is, the reflected light Se2 forms an aerial image AI22 and displays it in the line-of-sight direction LOS.

[0051] According to the second embodiment, an aerial image can be displayed on the -Z direction side of the reflective surface of the reflective member 2. In the aerial image display device 1A according to the second embodiment, by using a polarizing display for the display 10A, it is not necessary to place a field of view control film or the like on the optical path to remove transmitted light from the display 10A.

[0052] Furthermore, similar to the first embodiment, the aerial image display device 1A can adjust the position of the starting point D1, which is the other end of the display 10A, to the +Z side of the lower end of the reflective surface of the reflective member 2. For this reason, the aerial image display device 1A can be used simply by placing it on the reflective surface of the existing reflective member 2. In other words, the optical system of the aerial image display system 5A can be completed on a tabletop.

[0053] Furthermore, according to the second embodiment, by extending the display position toward the retroreflective material, it becomes possible to represent aerial images that span across the reflective surface. Therefore, it becomes possible to broaden the range of video expression.

[0054] [Third Embodiment] Next, an aerial image display device 1 according to a third embodiment will be described. The aerial image display device 1C according to the third embodiment differs from the aerial image display device 1 according to the first embodiment in that it further includes mirrors 16C and 17C. The other structures of the third embodiment are substantially the same as those of the first embodiment. The structures of mirrors 16C and 17C will be mainly described below.

[0055] Figure 8 is a plan view showing an example of an aerial image display device according to the third embodiment. Figure 8 corresponds to the view of Figure 2 in the first embodiment in the -Z direction (XY plan view from the +Z side). The aerial image display device 1C according to the fourth embodiment includes a display 10, a beam splitter 12, a retroreflective material 14, a mirror 16C, and a mirror 17C.

[0056] The mirror 16C is provided, for example, in the shape of a plate extending along the ZX plane. When viewed in the -Z direction (in an XY plane view seen from the +Z side), the mirror 16C is in contact with one end of the beam splitter 12 and the retroreflective material 14.

[0057] 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 is in contact with the beam splitter 12 and the other end of the retroreflective material 14 (the end opposite to the side on which the mirror 16C is provided).

[0058] Figure 9 is a plan view showing an example of the imaging optical path of an aerial image displayed by the aerial image display device according to the fourth embodiment. As shown in Figure 9, the aerial image display device 1C can display the aerial image AI4 in the line of sight LOS by displaying the display image DI4 on the display surface of the display 10.

[0059] Of the light emitted from the display 10, the light that is imaged 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 the display 10, the light that is imaged by following an optical path that passes through mirror 16C or mirror 17C is called emitted light Pa42.

[0060] The emitted light Pa42 from the display 10 is P-polarized light. The emitted light Pa42 is totally reflected by the reflective surface of, for example, the mirror 16C. The totally reflected emitted light Pa42 is then totally reflected by the reflective surface of the reflective polarizing film 11 on the beam splitter 12. The point at which the emitted 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 retroreflective material 14.

[0061] The reflected light Pb42 is retroreflective by the retroreflective material 14 via the waveplate 13. The point at which the reflected light Pb42 is retroreflective by the retroreflective material 14 is called the retroreflective material reflection point 14C2. The reflected light Pb42 passes through the waveplate 13 twice during the retroreflection process. The reflected light Pb42 that has passed through the waveplate 13 twice is called the reflected light Sc42. The reflected light Sc42 becomes S-polarized by retroreflection via the waveplate 13.

[0062] The reflected light Sc42 is retroreflected in the direction of 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 called transmitted light Sd42.

[0063] The transmitted light Sd42 is totally reflected by the reflective surface of the mirror 16C. The totally reflected transmitted light Sd42 is reflected by the reflective surface of the reflecting member 2. The point at which the transmitted light Sd42 is reflected by the reflecting member 2 is called the reflecting point 2C2. The reflected transmitted light Sd42 is called the reflected light Se42. The reflected light Se42 forms an image of the aerial image AI4 and displays it in the line of sight. The field of view of the aerial image AI4 formed by the reflected light Se42 is expanded by the mirror 16C. As described above, the emitted light Pa42 that is emitted from the display 10 in the Y direction and extends beyond the beam splitter 12 can also be used to form the image of the aerial image AI4, thereby expanding the field of view of the aerial image AI4.

[0064] The case described above concerns the case where the emitted light Pa42 is totally reflected by mirror 16C, but the same applies when the emitted light Pa42 is totally reflected by mirror 17C. The field of view of the aerial image AI4 is expanded because the reflected light Se42 can be imaged after passing through mirrors 16C and 17C.

[0065] According to the aerial image display device 1C of the third embodiment described above, the viewing range of the aerial image in the horizontal direction can be expanded.

[0066] If the aerial image display device 1C does not have mirrors 16C and 17C, the horizontal (XY direction) viewing range in which the aerial image can be observed without any loss of detail is limited by the width of the retroreflective material, 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 range may be narrowed.

[0067] In contrast, the aerial image display device 1C according to the third embodiment further includes mirrors 16C and 17C. By having mirrors 16C and 17C, the aerial image display device 1C can also utilize light (emitted light Pa42) emitted from the display 10 in the Y direction that the reflective polarizing film 11 cannot directly receive for imaging the aerial image AI4.

[0068] In other words, the aerial image display device 1C can cause the reflective polarizing film 11 to receive the emitted light Pa 42 by totally reflecting it with the mirror 16C or mirror 17C. When the reflective polarizing film 11 receives the emitted light Pa 42, the emitted light Pa 42 can be used to form the aerial image AI 4, and as a result the field of view of the aerial image AI 4 is expanded. This has the same effect as expanding the reflective polarizing film 11 in the Y direction.

[0069] Thus, by having mirrors 16C and 17C, the aerial image display device 1C can expand the horizontal viewing range of the aerial image without changing the size of the beam splitter 12, etc.

[0070] Furthermore, similar to the first embodiment, in the aerial image display device 1C according to the third embodiment, by using a polarizing display for the display 10, it is not necessary 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. In other words, 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 100% reflectivity is used for the reflective surface of the reflective member 2, the aerial image AI 4 can theoretically be imaged with 100% brightness. For this reason, the aerial image display device 1C according to the third embodiment can improve user visibility.

[0071] Furthermore, similar to the first embodiment, the aerial image display device 1C can be configured so that light emitted from the display 10 does not directly enter the retroreflective material 14 by adjusting the angle γ. Therefore, the aerial image display device 1C can be designed so that, theoretically, no stray light from the display 10 is generated.

[0072] Furthermore, similar to the first embodiment, the aerial image display device 1C uses retroreflective material and a beam splitter, and does not use retrotransmitting optical elements such as MMAP. For this reason, it is relatively easy to enlarge the device, and it is possible to enlarge the aerial image.

[0073] Furthermore, similar to the first embodiment, the aerial image display device 1C can adjust the position of the starting point D1, which is the other end of the display 10, to the +Z side of the lower end of the reflective surface of the reflective member 2. For this reason, the aerial image display device 1C 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.

[0074] The horizontal field of view in which an aerial image can be observed without any loss of detail is determined by the width of the retroreflective material, beam splitter, and reflective surface, and is therefore limited. In the third embodiment, mirrors 16C and 17C are installed at both ends of the optical system, and the light emitted laterally from the display 10 is also used to form the aerial image. In this way, the widest field of view can be obtained by installing the mirrors perpendicular to the reflective surface. In other words, according to the third embodiment, the horizontal field of view can be expanded.

[0075] [Fourth Embodiment] In addition to the first to third embodiments described above, two-sided images can be combined. Rather than being limited to the representation of an aerial image on a single surface, further image expression can be added, for example, by using the operating surface of a tablet device as a reflective surface. Furthermore, by laminating a glossy film onto the tablet device to increase glossiness and reduce roughness, it is possible to display an aerial image with better brightness and image quality. In this way, it becomes possible to represent images using two surfaces.

[0076] Furthermore, a three-dimensional aerial image may be displayed using a stereoscopic display. Alternatively, the optical system may be made upright, with the reflective surface serving as a wall. Furthermore, the system may be inverted, with the reflective surface serving as a ceiling.

[0077] Furthermore, arranging the retroreflective material so that it is perpendicular to the line of sight improves brightness efficiency, so the angle of the retroreflective material can be changed to match the line of sight. Using a prism-type retroreflective material will increase the reflectivity when the angle of incidence is 0°.

[0078] In the case of bead-type retroreflective materials, the difference in reflectivity is small around an incident angle of 0°, but it is effective as a measure to reduce brightness when the line of sight is moved to its upper limit.

[0079] Furthermore, various modifications can be applied to the first, second, third, and fourth embodiments described above.

[0080] In the embodiment described above, the displays 10 and 10A may be positioned at an angle of approximately 90 degrees 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. Alternatively, they may be positioned at an angle greater or less than 90 degrees with respect to the line segment connecting the starting point A1 and the starting point C1. In this case, the display image shown on the display surface of the display will be tilted, thereby allowing the aerial image to be displayed at an angle. Furthermore, for example, the brightness efficiency can be increased by positioning the front surfaces of the display surfaces of the displays 10 and 10A to face the beam splitter 12.

[0081] Furthermore, although the above-described embodiment described the case in which flat displays are used for display 10 and display 10A, it is not limited to this. For example, a three-dimensional aerial image may be displayed by using stereoscopic displays for display 10 and display 10A.

[0082] Furthermore, the reflective surface of the reflective member 2 is not limited to the floor, desk, etc. For example, a wall or ceiling may be used as the reflective surface of the reflective member 2. The reflective surface of the reflective member 2 may be positioned in any orientation.

[0083] Furthermore, although the above-described embodiment described a case where the user's line of sight LOS is a combined direction of the +X direction and the -Z direction, it is not limited to this. For example, the user's line of sight LOS may be a direction perpendicular to the retroreflective material 14 when viewed in the Y direction. The arrangement and angle of the retroreflective material 14 may be adjusted so that the orientation of the user's line of sight LOS and the retroreflective material 14 are perpendicular. For example, when the orientation of the user's line of sight LOS and the retroreflective material 14 are perpendicular, the luminance efficiency can be increased. Also, when a prism-type retroreflective material is used for the retroreflective material 14, the reflectance is high when the incident angle is 0 degrees. Also, when a bead-type retroreflective material is used for the retroreflective material 14, it is effective as a measure to reduce luminance when the user's line of sight LOS is moved to the upper limit in the Z direction.

[0084] Furthermore, although the above-described embodiment described the case in which P-polarized light is emitted from the display, it is not limited to this. 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 are provided that reflect S-polarized light and transmit P-polarized light. When the light emitted from the display is unpolarized, for example, an absorbing polarizing plate is provided between the display and the beam splitter that selectively transmits light of the polarization axis (for example, P-polarized) reflected by the reflective polarizing film 11 and the beam splitter.

[0085] The first embodiment, the third embodiment, or the fourth embodiment can be combined with each other. Furthermore, the second embodiment, the third embodiment, or the fourth embodiment can be combined with each other.

[0086] Furthermore, the present invention is not limited to the embodiments described above, and can be modified in various ways during implementation without departing from its essence. Also, each embodiment may be combined as appropriate, and in that case, combined effects can be obtained. Moreover, the above embodiments include various inventions, and various inventions can be extracted by selecting combinations from the multiple disclosed constituent elements. For example, if the problem can be solved and effects obtained even if some constituent elements are deleted from all the constituent elements shown in the embodiment, then the configuration with these deleted constituent elements can be extracted as an invention.

[0087] 1...Aerial image display device 1A...Aerial image display device 1C...Aerial image display device 2...Reflective surface 5...Aerial image display system 5A...Aerial image display system 9...Control device 10...Display 10A...Display 11...Reflective polarizing film 12...Beam splitter 13...Quarter wave plate 14...Retroreflective material 14C2...Retroreflective material reflection point 16C...Mirror 17C...Mirror 90...Processor 91...ROM 92...RAM 93...Storage 94...Interface 101...Display section 102...Display extension section.

Claims

1. An aerial image display device comprising: a display unit for displaying an object; a beam splitter provided at a first angle with respect to a reference plane, which reflects a portion of the emitted light from the display unit and transmits a portion of it; and a retroreflective material that retroreflects the transmitted or reflected emitted light to obtain retroreflected light, wherein the retroreflected light reflected or transmitted by the beam splitter is guided to a reflective surface provided at a second angle inclined with respect to the reference plane in a direction directly facing the observer, thereby forming an aerial image originating from the object.

2. An aerial image display device comprising: a display unit for displaying an object; a beam splitter provided at a first angle with respect to a reference plane and having reflective polarization characteristics that reflect one polarization of the light emitted from the display unit and transmit the other polarization; and a retroreflective material having phase difference characteristics that retroreflects the transmitted or reflected light and obtains retroreflected light with a phase shift of π / 2 in the polarization direction; wherein the retroreflected light reflected or transmitted from the beam splitter is guided to a reflective surface provided at a second angle inclined with respect to the reference plane in a direction directly facing the observer, and retroreflected light is transmitted or reflected from the beam splitter, thereby forming an aerial image originating from the object.

3. The aerial image display device according to claim 2, wherein the reflective surface includes a reflective surface having polarization properties that reflect retroreflected light in one polarization direction.

4. The aerial image display device according to claim 1 or 2, wherein the display device is a polarizing display having specific polarization characteristics.

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