WO2024190160A1 - Aerial image display apparatus having expanded viewing angle - Google Patents

Abstract

Provided is an aerial image display apparatus with which a viewing angle can be expanded.　This aerial image display apparatus comprises: a pair of optical plates that are provided to be close to each other at a predetermined angle; a pair of display devices that are supported to face the pair of optical plates at predetermined positions; and a control device that transmits image signals to the pair of display devices. The aerial image display device generates a pair of real images close to each other by images on the pair of display devices being retroreflectively transmitted through the pair of optical plates respectively corresponding thereto. Consequently, a viewing angle indicating a range in which a user can see an aerial image is greatly expanded, thereby making it possible to achieve a large-screen aerial image.

Description

Aerial image display device with expanded viewing angle

The present invention relates to an aerial image display device, and in particular to an aerial image display device with an expanded viewing angle.

In recent years, interest in aerial image display devices has been growing. One of the reasons for this is the need for contactless solutions amid the COVID-19 pandemic. In other words, they can be used in combination with sensors to replace touch panels. For example, at bank ATMs, supermarket self-checkouts, corporate reception desks, hotel check-ins, and other locations, an unspecified number of users operate the same touch panels. Such touch panels can become potential routes of infection. To avoid this risk, it is necessary to disinfect the touch panel every time a user changes, but such a procedure is quite time-consuming and difficult to carry out adequately.

A non-contact interface using an aerial image display device can be used just as easily as a conventional touch panel, and can avoid the risk of infection without the hassle. For example, in Patent Document 1, since it is unhygienic for the surgeon to touch a pointing device such as a computer mouse during surgery, the surgeon operates a mouse on a non-contact remote pointer control device displayed using aerial imaging technology. An example of a special optical element that can be used with such aerial imaging technology is the optical imaging device described in Patent Document 2.

The way images float in empty space using aerial imaging technology is impactful in itself and helps create a futuristic atmosphere. For this reason, many applications beyond infection prevention measures are conceivable. For example, if applied to digital signage, it can attract more attention. The technology disclosed in Patent Document 3 shows an example of using it to replace barriers at ticket gates in stations. Furthermore, when displayed as an aerial image, it gives a sense of three-dimensionality as it floats above the surroundings, making it highly entertaining, and it is expected that it will be applicable to games and the like.

JP 2018-147054 A International Publication No. 2009/131128

Optical plates used in aerial imaging technology are of two types: retrotransmissive and retroreflective. Figure 9 is a perspective view showing a conventional aerial image display device that uses a retrotransmissive optical plate, and Figure 10 is a cross-sectional view explaining the principle of the aerial image display device shown in Figure 9. Note that a retrotransmissive optical plate is an optical element that has in-plane reflectivity and normal transparency for light rays incident on the plate surface.

As shown in these figures, the aerial image display device 101 is equipped with a box-shaped housing 110, an LCD display 120 installed inside the housing at an angle of approximately 45 degrees to the horizontal plane, an optical plate 130 placed horizontally on the top surface of the housing 110, a pair of infrared LEDs 132 and a pair of infrared cameras 134 for detecting operations provided in front of the optical plate 130, a speaker 139, and a control device 140 that processes the input and output signals of each of these elements.

The optical plate 130 has an entrance surface 131 facing downwards, facing the display surface 124 of the liquid crystal display 120, and an exit surface 133 facing directly upwards. The image on the display surface 124 of the liquid crystal display 120 is then focused again as an aerial image 104 via the optical plate 130 at the same distance on the opposite side, forming the same image as the original.

The infrared LEDs 132 and infrared camera 134 for operation detection capture an image of the user's hand near the aerial image 104 to detect the position and movement of the hand. Therefore, the image capture device consisting of the infrared LEDs 132 and infrared camera 134 constitutes an operation detection unit that detects operations performed by the user on the aerial image 104. That is, the pair of infrared cameras 134 capture images of the user's hand from the left and right separately, and the control device 140 processes the obtained infrared images to detect the movement of the user's hand. For example, when controls I such as buttons, checkboxes, and drop-down menus are displayed on the aerial image 104 and the user performs a gesture action to operate one of them with his or her finger, the control device 140 detects the action via the operation detection unit and performs various processes accordingly, such as changing the display of the aerial image 104.

However, in such an optical system, the scattered light that does not pass through the optical plate 130 cannot be seen, so there is a limit to the range in which a user can properly view the aerial image.

Referring to FIG. 10, aerial image 104 is a real image created by concentrating light from optical plate 130, so the range that the user can see is limited to the viewing angle of optical plate 130 as seen from the viewpoint. For example, when viewed from viewpoint VP1, aerial image 104 (real image) falls within viewing angle PA1, so the entire aerial image 104 can be seen from viewpoint VP1.

However, when viewed from viewpoint VP2, which is lower, aerial image 104 does not fall within viewing angle PA2, and the upper RU of aerial image 104 is not visible from viewpoint VP2. Therefore, the user must find a position where the entire aerial image 104 can be seen. Also, it is possible that an adult can see the entire aerial image 104, but a child can only see the lower half.

The object of the present invention is to provide a large-screen aerial image display device with a wide viewing angle.

In order to solve the above problems, an aerial image display device according to one aspect of the present invention comprises a pair of optical plates arranged close to each other at a predetermined angle, a pair of display devices supported facing the pair of optical plates at predetermined positions, and a control device that transmits image signals to the pair of display devices, and is characterized in that the images of the pair of display devices are retrotransmitted through the pair of corresponding optical plates, thereby generating a pair of real images close to each other.

In one preferred embodiment, the real images are generated on the same plane, with parts of them overlapping, and the overlapping parts of the real images displaying the same image.

Furthermore, in one preferred embodiment, the pair of optical plates each have the same rectangular shape and are arranged so that one side of each of the optical plates is in contact with each other.

Furthermore, in one preferred embodiment, the angle between the pair of optical plates is in the range of 60 degrees to 105 degrees.

The aerial image display device of the present invention significantly expands the viewing angle, which indicates the range within which aerial images can be seen by the user, making it possible to realize aerial images on a large screen.

FIG. 1 is an explanatory diagram for explaining the principle by which the viewing angle is expanded by the aerial image display device of the present invention. FIG. 2 is a perspective view showing the aerial image display device 1 according to the first embodiment of the present invention. FIG. 3 is a diagram showing an example of a display screen of the liquid crystal display of the aerial image display device 1 according to the first embodiment of the present invention, and an example of an aerial image produced thereby. FIG. 4 is a perspective view showing an aerial image display device 2 according to a second embodiment of the present invention. FIG. 5 is a diagram showing an example of a display screen of a liquid crystal display of an aerial image display device 2 according to a second embodiment of the present invention, and an example of an aerial image produced thereby. FIG. 6 is a diagram showing an example of the arrangement of the display device and the optical plate in the aerial image display device of the present invention. FIG. 7 is a diagram showing another example of the arrangement of the display device and the optical plate in the aerial image display device of the present invention. FIG. 8 is a diagram showing still another example of the arrangement of the display device and the optical plate in the aerial image display device of the present invention. FIG. 9 is a perspective view showing a conventional aerial image display device. FIG. 10 is a cross-sectional view showing a conventional aerial image display device.

First, the principle of expanding the viewing angle of the aerial image display device according to the present invention will be explained with reference to Figure 1. Conventionally, as shown in Figure 10, this was composed of one retro-transmissive optical plate and one display device (such as a liquid crystal display), resulting in a narrow viewing angle. In the present invention, an additional pair of retro-transmissive optical plates and display devices is added, and the viewing angle is expanded by the corresponding pairs of optical plates and display devices.

In other words, like FIG. 10, FIG. 1 is a side view of the arrangement of an optical system, and is made up of a pair of optical plates PA, PB and a pair of display devices (such as liquid crystal displays) LA, LB. The pair of optical plates PA, PB each have the same rectangular shape, and are arranged with one of their sides joined at a fixed angle (here, 90 degrees). The display devices LA, LB are also arranged opposite the optical plates PA, PB at a specified angle (here, 45 degrees). Overall, the display devices LA, LB and the optical plates PA, PB are arranged symmetrically with respect to a plane that passes through the joint sides of the optical plates PA, PB and bisects the angle between the optical plates PA, PB.

The relative arrangement of the optical plate PA and the display device LA is the same as in the past, and the image on the display screen of the display device LA is formed as a real image RA at a position that is symmetrical across the optical plate PA. Similarly, the relative arrangement of the optical plate PB and the display device LB is the same as in the past, and the image on the display screen of the display device LB is formed as a real image RB at a position that is symmetrical across the optical plate PB.

The position and inclination of the real images RA and RB formed in the space between the optical plates PA and PB are determined by the joining angle of the optical plates PA and PB and the arrangement of the display devices LA and LB, but in this example, the real images RA and RB are formed on the same plane (a plane perpendicular to the planes of the display devices LA and LB) and partially overlap.

Generally, the viewing angle of an aerial image (real image) is limited by the viewing angle of the optical plate. In this invention, two optical plates are used, so the viewing angle is expanded to about twice that of conventional methods. In other words, whereas conventionally the viewing angle of an aerial image (real image) was limited to the viewing angle of one optical plate, in this invention it is expanded to the viewing angle of both optical plates combined.

For example, if we assume that the optical system consists only of the optical plate PA and the display device LA, the real image RA can be seen in its entirety from viewpoint PH looking in from above, but from viewpoint PL looking in from the side, only the lower part of the real image RA that falls within the range of the visual angle of the optical plate PA can be seen, and the upper part that falls outside of that cannot be seen.

Similarly, if we assume that the optical system consists only of the optical plate PB and the display device LB, the entire real image RB can be seen from viewpoint PL looking in from the side, but from viewpoint PH looking in from above, only the upper part of the real image RB that falls within the range of the visual angle of the optical plate PB can be seen, and the lower part that falls outside of that range cannot be seen.

Here, the display images of the display devices LA, LB are configured so that the partially overlapping real images RA and RB form a single aerial image. That is, the overlapping area of real images RA and RB is made to have the same image content. In other words, the image area consisting of partially overlapping real images RA and RB is made to be a single drawing area to form the image content. From the above, it can be seen that the aerial image display device of the present invention not only makes it possible to expand the viewing angle but also to display aerial images on a large screen.

Needless to say, for real images RA and RB to form a single continuous image area without gaps, the optical plates PA and PB must be in complete contact with one side.

As an example of such a retro-transmitting optical plate, the optical imaging element described in JP 2011-175297 A can be used. This optical imaging element is realized by arranging a large number of mutually orthogonal planar light reflecting sections at a fixed pitch. In addition, a structure such as a two-sided corner reflector in which reflective surfaces are formed on the side of a square hole as described in Japanese Patent No. 4900618 can also be used.

Below, an embodiment of the aerial image display device according to the present invention will be described with reference to the attached drawings. Figure 2 is a perspective view showing the aerial image display device 1 when performing biometric authentication according to an embodiment of the present invention.

As shown in Figure 2, the aerial image display device 1 comprises a chair-shaped housing 10, a pair of LCD displays 20a, 20b installed inside the housing at an angle of approximately 45 degrees to the horizontal plane, a pair of optical plates 25a, 25b placed horizontally and vertically on the seat and backrest of the chair-shaped housing 10, a motion sensor 30 for detecting operations installed in front of the above, a speaker 39, and a control device (not shown) that processes input and output signals from each of these elements. The motion sensor 30 consists of a pair of infrared LEDs 32 and a pair of infrared cameras 34.

The relative arrangement of the pair of liquid crystal displays 20a, 20b and the pair of optical plates 25a, 25b is the same as the display devices LA, LB and optical plates PA, PB shown in FIG. 1, and the arrangement of the liquid crystal displays 20a, 20b and optical plates 25a, 25b when the aerial image display device 1 shown in FIG. 2 is viewed from the right side corresponds to the display devices LA, LB and optical plates PA, PB in FIG. 1.

In other words, the optical plates 25a, 25b are each the same rectangular shape, and are arranged with one side in contact with the other at a fixed angle (here 90 degrees). The liquid crystal displays 20a, 20b are arranged facing the optical plates 25a, 25b at a specified angle (here 45 degrees). Overall, the liquid crystal displays 20a, 20b and the optical plates 25a, 25b are arranged symmetrically with respect to a plane that passes through the joint sides of the optical plates 25a, 25b and bisects the angle between the optical plates 25a, 25b.

Therefore, the image on the display screen of LCD display 20a is formed as a real image at a planar symmetrical position across optical plate 25a, and the image on the display screen of LCD display 20b is formed as a real image at a planar symmetrical position across optical plate 25b. And in the aerial image display device 1, the images on the display screens of LCD displays 20a and 20b are also formed as a single aerial image 4 on the same plane. Again, the overlapping parts of the two real images form the same image.

For example, if the display screen of LCD display 20a is displayed as shown in Figure 3(A) and the display screen of LCD display 20b is displayed as shown in Figure 3(B), the aerial image seen by the user will be as shown in Figure 3(C). The display screen is adjusted so that the two real images of the star-shaped part in the middle are in the same position, but the user will only see one of the real images depending on the position of their eyes.

The infrared LEDs 32 and infrared camera 34 of the motion sensor 30 capture images of the user's hands near the aerial image 4 to detect the position and movement of the user's hands. That is, the pair of infrared cameras 34 capture images of the left and right sides of the user's hand separately, and the control device processes the resulting infrared images to detect the movement of the user's hands. For example, when controls such as buttons, checkboxes, and drop-down menus are displayed on the aerial image 4 and the user makes a gesture to operate one of them with his or her finger, the control device detects the action via the operation detection unit and performs various processes accordingly, such as changing the display of the aerial image 4. Therefore, the aerial image 4 functions as a non-contact interface. The detection range of the operation detection unit is determined by the emission angle of the infrared LEDs 32 and the angle of view of the infrared camera 34.

The control device that controls the LCD displays 20a, 20b and the motion sensor 30 is essentially a small computer and is composed of a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), a storage device that stores various programs and data, an input/output interface, etc. As the input/output interface, for example, a USB port or a wireless LAN such as WIFI is implemented.

The aerial image display device 1 configured as described above has two optical plates 25a, 25b, which greatly expands the viewing angle, allowing both short and tall people to see the entire aerial image 4. In addition, the size of the aerial image 4 can be increased, allowing for a greater variety of expressions.

Next, a second embodiment of the aerial image display device according to the present invention will be described with reference to Figure 4. This aerial image display device 2 is similar to the aerial image display device 51 in Figure 2, except that the relative positions of the pair of liquid crystal displays 70a, 70b and the pair of optical plates 75a, 75b are kept the same, but tilted 90 degrees to the side.

In other words, as shown in the figure, the aerial image display device 2 comprises a housing 50 with an M-shaped cross section, a pair of left and right LCD displays 70a, 70b installed parallel to each other on the inside of both left and right sides of the housing 50, a pair of left and right optical plates 75a, 75b installed facing each of the pair of left and right LCD displays 70a, 70b at a 45 degree angle, a motion sensor 90 for detecting operations installed on the outside of the optical plates 75a, 75b, a speaker 89, and a control device (not shown) that processes the input and output signals of each of these elements. Here again, the motion sensor 90 consists of an infrared LED and an infrared camera.

Therefore, the relative arrangement of the pair of liquid crystal displays 70a, 70b and the pair of optical plates 75a, 75b is the same as that of the display devices LA, LB and optical plates PA, PB shown in FIG. 1, and the optical plates 75a, 75b each have the same rectangular shape and are arranged with one side in contact at a certain angle (here, 90 degrees). However, the pair of liquid crystal displays 70a, 70b and the pair of optical plates 75a, 75b stand upright on the left and right, respectively. Overall, the liquid crystal displays 70a, 70b and the optical plates 75a, 75b are arranged symmetrically with respect to a plane that passes through the joint sides of the optical plates 75a, 75b and bisects the angle between the optical plates 75a, 75b.

As explained in the principle diagram of Figure 1, the image on the display screen of LCD display 70a is formed as a real image at a position symmetrical with respect to the optical plate 75a, and the image on the display screen of LCD display 70b is formed as a real image at a position symmetrical with respect to the optical plate 75b. These two real images overlap on the same plane and are formed as a single aerial image 54. Again, the overlapping parts of the two real images form the same image.

For example, if the display screen of LCD display 70a is displayed as shown in Fig. 5(A) and the display screen of LCD display 70b is displayed as shown in Fig. 5(B), the aerial image seen by the user will be as shown in Fig. 5(C). The display screen is adjusted so that the two real images of the star-shaped part in the middle are in the same position, but the user will only see one of the real images depending on the position of their eyes.

It is assumed that the aerial image display device 51 will be viewed by the user while standing. As the vertical viewing angle of the aerial image display device 51 is small, it is preferable to view it from directly to the side, and the housing 50 is supported by legs 60 so that the aerial image 54 is positioned at about eye height.

The control device is essentially a small computer and is composed of a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), a storage device for storing various programs and data, an input/output interface, etc. Examples of input/output interfaces include a USB port and a wireless LAN such as WIFI.

Again, the infrared LEDs and infrared cameras of the motion sensors 90 installed on both sides of the optical plates 75a and 75b capture images of the user's hands near the aerial image 54 to detect the position and movement of the user's hands.

The aerial image display device 2 configured as described above has two optical plates 75a, 75b arranged horizontally, which allows for a large-screen aerial image 54 to be displayed, enabling a wider variety of expressions.

It is also possible to double the screen size by stacking another pair of liquid crystal displays 70a, 70b and a pair of optical plates 75a, 75b one on top of the other. However, in this case, the vertical viewing angle is narrow, so the viewpoints from which the entire aerial image can be viewed are limited, and the user cannot move from the viewing position from which that viewpoint can be obtained.

The aerial image display device of the present invention significantly expands the viewing angle, which indicates the range within which aerial images can be seen by the user, making it possible to realize aerial images on a large screen.

The above describes the aerial image display device according to the present invention based on an embodiment, but the present invention is not limited to this, and modifications may be made without departing from the spirit of the present invention, and if possible, the techniques described in each embodiment may be combined, or known techniques may be combined, etc.

For example, in the above embodiment, the pair of optical plates are arranged with one side in contact with each other at an angle of 90 degrees. The corresponding optical plate and the display device are arranged at an angle of 45 degrees. However, the present invention is not limited to this. In other words, the angle formed by the pair of optical plates may be slightly smaller or larger than 90 degrees. Specifically, an angle between approximately 60 degrees and 105 degrees will have a certain degree of practicality.

Furthermore, the corresponding optical plate and display device may be arranged at an angle other than 45 degrees. Specifically, an angle between approximately 30 degrees and 60 degrees will provide a certain degree of practicality. Furthermore, a pair of optical plates may be arranged with one side slightly spaced apart, without touching each other.

For example, as shown in FIG. 6, a pair of optical plates PA, PB may be arranged with one side of each plate at an angle of less than 90 degrees, and display devices LA, LB may be arranged at angles of less than 45 degrees relative to the optical plates PA, PB. In this case, the real images RA, RB are displayed side by side at an angle that is easy to see, not on the same plane, but on the inside.

Also, as shown in Figure 7, the pair of optical plates PA and PB may be arranged with one side slightly apart rather than in close contact with each other. In this case, a gap will be created between the real images RA and RB. Therefore, it will not be a continuous screen.

Furthermore, as shown in FIG. 8, a pair of optical plates PA and PB may be arranged such that one side of each plate is at an angle greater than 90 degrees. In this case, the real images RA and RB are not formed on the same plane but are formed at an angle to the outside.

In addition, in the above embodiment, a liquid crystal display is used as the display for projecting the aerial image 4, but the present invention is not limited to this, and an organic EL display, electronic paper, liquid crystal projector, etc. may also be used. In the case of a liquid crystal projector, a screen is installed at the position of the display device.

1, 2 Aerial image display device 10, 50 Housing 20a, 20b Liquid crystal display 25a, 25b Optical plate 25b Optical plate 30 Motion sensor 32 LED infrared 34 Infrared camera 39 Speaker 4, 54 Aerial image 60 Leg 70a, 70b Liquid crystal display 75a, 75b Optical plate 89 Speaker 90 Motion sensor 101 Aerial image display device 104 Aerial image 110 Housing 120 Liquid crystal display 124 Display surface 130 Optical plate 131 Incident surface 132 Infrared LED
133: Emission surface 134: Infrared camera 139: Speaker 140: Control device LA, LB: Display device PA, PB: Optical plate PA1, PA2: Viewing angle PH, PL: Viewpoint RA, RB: Real image RU: Upper portion VP1, VP2: Viewpoint

Claims (4)

A pair of optical plates provided close to each other at a predetermined angle;
a pair of display devices supported at predetermined positions facing each other on the pair of optical plates;
a control device for transmitting a video signal to the pair of display devices;
An aerial image display device characterized in that a pair of real images close to each other are generated by the images of the pair of display devices being retrotransmitted through the pair of corresponding optical plates. The aerial image display device according to claim 1, characterized in that the real images are generated on the same plane, parts of which overlap, and the overlapping parts of the real images display the same image. The aerial image display device according to claim 1, characterized in that the pair of optical plates each have the same rectangular shape and are arranged so that one side of each plate is in contact with the other. The aerial image display device according to claim 3, characterized in that the angle between the pair of optical plates is in the range of 60 degrees to 105 degrees.

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