JP6449120B2 - Aerial image display device and aerial image display method - Google Patents

Description

The present invention relates to an aerial image display device and an aerial image display method for displaying an aerial image.

  Conventionally, an aerial image display device that displays an aerial image by reflecting light emitted from a display that displays an image using an optical element is known (for example, see Non-Patent Document 1). Non-Patent Document 1 proposes a method of mechanically moving a display for displaying an image up and down in order to express the depth of a displayed aerial image.

"Alignment of aerial image and real object for mixed reality system", IEICE, June 2014

  However, the method described in Non-Patent Document 1 requires an actuator for mechanically moving the display, and thus it is difficult to reduce the size of the device.

An object of the present invention made in view of such circumstances is to provide a small aerial image display device and aerial image display method capable of displaying an aerial image having a plurality of depths.

In order to solve the above-described problems, a first aspect of the aerial image display device according to the present invention is a device that projects an aerial image into a space, and is disposed outside a housing and from the projector. One or more transmittance variable plates for projecting projection light, the transmittance of which can be variably controlled, and the light that is disposed inside the housing and projected on the transmittance variable plate is incident on the housing. An optical element that forms an aerial image inside the body, and the position of the aerial image is controlled by controlling the transmittance of the transmittance variable plate, and is the back surface of the transmittance variable plate, An entity is disposed outside the housing . A second aspect of the aerial image display device according to the present invention is a device that displays an aerial image in space, and is arranged outside the housing and the video input from the video output device. One or more transmittance variable plates capable of variably controlling the transmittance, and the light emitted from the transmittance variable plate is incident on the interior of the housing. An optical element that forms the above aerial image, and the position of the aerial image is determined by a distance between the transmittance variable plate and the housing, and is a rear surface of the transmittance variable plate and the housing. It is characterized in that the entity is arranged outside the.

Further, the aerial image display method according to the present invention is an aerial image display method for displaying an aerial image in a space in a housing, on the back surface of one or more transmittance variable plates arranged outside the housing. A step of arranging an entity; a step of projecting projection light by a projector; a step of projecting the projection light by the transmittance variable plate; and an optical element disposed inside the casing. Incident light projected onto the variable rate plate to form an aerial image inside the housing; and controlling the transmittance of the variable transmittance plate to control the position of the aerial image. It is characterized by including .

  According to the present invention, it is possible to realize the depth expression of an aerial image without increasing the size of the apparatus.

1 is a side view showing a configuration example of an aerial image display system that includes a spatial image display device according to a first embodiment of the present invention and uses a rear projector. 1 is a side view showing a configuration example of an aerial image display system including a spatial image display device according to a first embodiment of the present invention and using a front projector. It is a figure explaining the operation | movement which displays the same aerial image in a different position by the aerial image display apparatus which concerns on the 1st Embodiment of this invention. It is a figure explaining the operation | movement which displays a different aerial image in a different position by the aerial image display apparatus which concerns on the 1st Embodiment of this invention. It is a figure explaining the operation | movement which displays a three-dimensional image by the aerial image display apparatus which concerns on the 1st Embodiment of this invention. It is a side view which shows the modification of an aerial image display system provided with the aerial image display apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows operation | movement of the 2nd structural example of the aerial image display apparatus which concerns on the 1st Embodiment of this invention. It is a side view which shows the structural example of the aerial image display system provided with the aerial image display apparatus which concerns on the 2nd Embodiment of this invention. It is a figure explaining operation | movement of the aerial image display apparatus which concerns on the 2nd Embodiment of this invention. It is a side view which shows the structural example of the aerial image display system provided with the aerial image display apparatus which concerns on the 3rd Embodiment of this invention. It is a figure explaining operation | movement of the aerial image display apparatus which concerns on the 3rd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a side view showing a configuration example of an aerial image display system including an aerial image display device according to the first embodiment of the present invention. In the example illustrated in FIG. 1, the aerial image display system 1 includes the aerial image display device 10 a according to the first embodiment of the present invention, a projector 20, and a video output device 30. The aerial image display device 10 a includes a housing 11, an optical element 12, one or more screens 13 (transmittance variable plates), and a control unit 14.

  The aerial image display device 10 a is a device that allows the observer 100 to visually recognize the aerial image of the image displayed on the screen 13.

  The casing 11 is formed in a rectangular tube shape, and an opening is provided in one end portion 11a so that the observer 100 can observe the inside. Further, the surface 11b of the housing 11 facing the screen 13 is provided with an opening so that light from the screen 13 can enter. The opening may be closed or covered with a transparent member.

  The screen 13 is a screen whose transmittance can be controlled. For example, a liquid crystal film having low transmittance when no voltage is applied and high transmittance when a voltage is applied can be used. Since the screen 13 is milky white when the transmittance is low, the projection light (projection image) from the projector 20 can be projected. One or more screens 13 are arranged outside the housing 11.

  The video output device 30 is a PC, for example, and outputs video to the projector 20.

  The projector 20 projects the video input from the video output device 30 onto the screen 13. As shown in FIG. 1, the projector 20 may be a rear projector disposed on the back surface of the screen 13, or may be a front projector disposed on the front surface of the screen 13.

  When the transmittance of the screen 13 is set low, the screen 13 is black when the transmittance is extremely low. In such a case, if the projector 20 is arranged on the back surface of the screen 13, light is blocked by the screen 13 having low transmittance (that is, non-transparent). It needs to be a projector. In the example shown in FIG. 2, the screen 13-2 is controlled to have low transmittance by the control unit 14-2, and the screens 13-1 and 13-3 are controlled to have high transmittance by the control units 14-1 and 14-3, respectively. It shows the state being done.

  The control unit 14 controls the transmittance of the screen 13 by turning on / off the voltage. Note that the control unit 14 may be included in the video output device 30. One control unit 14 may control the transmittance of the plurality of screens 13.

  The optical element 12 is, for example, a transparent plate or a half mirror, and is disposed inside the housing 11. The optical element 12 is provided with an inclination of approximately 45 degrees toward the viewer 100 side, and enters the light (video) projected on the screen 13 and reflects it in the direction toward the viewer 100, thereby forming a virtual image. Create an aerial image. When the optical element 12 is a real image mirror using a micromirror array, the optical element 12 is provided with an inclination of approximately 45 degrees in a direction away from the viewer 100 and is projected onto the screen 13. (Image) is incident and reflected in a direction toward the viewer 100 to form a real aerial image. By providing such an optical element 12, an aerial image can be displayed in the space inside the housing 11.

  Next, an operation of displaying the same aerial image on the aerial image display device 10a at different positions will be described with reference to FIG. Here, an example will be described in which two screens 13-1 and 13-2 are arranged in parallel in the lower part of the housing 11 when viewed from the observer 100. FIG. 3A is a side view showing a configuration example of the aerial image display system 1 when an aerial image is displayed on the front side of the observer 100, and FIG. 3B is a front side of the observer 100. It is a figure which shows the aerial image observed by the observer 100 in the case of displaying an aerial image on the side. FIG. 3C is a side view showing a configuration example of the aerial image display system 1 when an aerial image is displayed on the back side with respect to the observer 100, and FIG. It is a figure which shows the aerial image observed by the observer 100 in the case of displaying an aerial image on the side.

  When the aerial image is displayed on the near side with respect to the observer 100, as shown in FIG. 3A, the control unit 14-1 controls and controls the transmittance of the screen 13-1 to be low. The unit 14-2 performs control so that the transmittance of the screen 13-2 is increased. In FIG. 3A, the dotted line of the screen 13-2 means that the transmittance of the screen 13-2 is higher than the transmittance of the screen 13-1. By increasing the transmittance of the screen 13-2, the video (object A) projected from the projector 20 is transmitted through the screen 13-2 and projected onto the screen 13-1. The light projected on the screen 13-1 enters the optical element 12.

  The optical element 12 reflects the light projected on the screen 13-1 in a direction toward the viewer 100. When the screen 13-1 is arranged so as to be in contact with the casing 11 without providing a distance, as shown in FIGS. 3A and 3B, the aerial image A ′ corresponding to the object A is displayed in the casing. 11 is displayed on a space plane perpendicular to the facing surface 11b, including a contact point (base point) between the facing surface 11b and the optical element 12 with respect to the screen 13-1.

  On the other hand, when the aerial image is displayed on the back side with respect to the observer 100, the control unit 14-1 controls the transmittance of the screen 13-1 to be high as shown in FIG. The control unit 14-2 controls the transmittance of the screen 13-2 to be low. In FIG. 3C, the dotted line of the screen 13-1 means that the transmittance of the screen 13-1 is higher than the transmittance of the screen 13-2. By increasing the transmittance of the screen 13-1, the light projected onto the screen 13-2 by the projector 20 passes through the screen 13-1 and enters the optical element 12.

  The optical element 12 reflects the light projected on the screen 13-2 in a direction toward the observer 100. When the screen 13-2 is arranged in a direction away from the housing 11 by a distance D from the screen 13-1, as shown in FIGS. 3C and 3D, the screens 13A and 3B are used. Compared to the case, an aerial image A ′ corresponding to the object A is displayed on the space plane behind the distance D.

  In this way, the optical element 12 controls the position of the aerial image by reducing the transmittance of one of the plurality of screens 13 and increasing the transmittance of the remaining screens. Assuming that the screen 13-n is a screen whose transmittance is controlled to be low among the plurality of screens 13, the position of the aerial image is defined by the distance from the surface of the housing 11 facing the screen 13 to the screen 13-n. The

  Next, an operation of displaying different aerial images at different positions by the aerial image display device 10a will be described with reference to FIG. In this example, three screens 13 of screens 13-1, 13-2, and 13-3 are arranged in the order closer to the housing 11, and only one of these screens is controlled to have low transmittance.

  As shown in FIG. 4A, when the transmittance of the screen 13-1 is controlled to be low, the object A projected from the projector 20 is projected onto the screen 13-1. When the transmittance of the screen 13-2 is controlled to be low, the object B projected from the projector 20 is projected onto the screen 13-2. When the transmittance of the screen 13-3 is controlled to be low, the object C projected from the projector 20 is projected onto the screen 13-3. The projector 20 may project the objects A, B, and C at the same time, or may project only the object to be projected onto the screen 13 controlled to have low transmittance.

  The control unit 14 may switch (select) the screen 13 having a low transmittance continuously from a plurality of sheets. For example, the transmittance of only the screen 13-1 is lowered at time t, the transmittance of only the screen 13-2 is lowered at time t + 1, the transmittance of only the screen 13-3 is lowered at time t + 2, and the screen 13- is lowered at time t + 3. The screen 13 having a low transmittance is switched in an arbitrary order such that the transmittance of only the screen 2 is lowered and only the screen 13-1 is lowered at the time t + 4.

  Here, the control unit 14 continuously switches the screen 13 having a low transmittance at intervals shorter than the time resolution of the human eye, thereby causing the observer 100 to perceive an object having a plurality of layers overlapped by the afterimage effect, It can appear as if multiple layers are displayed at once. That is, when the transmittance of each screen 13 shown in FIG. 4A is controlled at a high speed, as shown in FIG. 4B, the aerial image A ′ of the object A is perceived in the layer in front of the observer 100. The middle layer can perceive the aerial image B ′ of the object B, and the inner layer can perceive the aerial image C ′ of the object C. Note that the temporal resolution of the human eye is about 50 ms to 100 ms.

  Next, an operation for displaying a three-dimensional space image (three-dimensional image) by the space image display device 10a will be described with reference to FIG. In this example, three screens 13 of screens 13-1, 13-2, and 13-3 are arranged in the order closer to the housing 11, and only one of these screens is controlled to have low transmittance.

  When the stereoscopic image shown in FIG. 5A is displayed, the stereoscopic image is divided in the depth direction according to the number of screens 13. That is, as shown in FIG. 5B, when the number of screens 13 is three, the stereoscopic image is divided into three in the depth direction to form stereoscopic images a, b, and c. As shown in FIG. 5C, when the transmittance of the screen 13-1 is controlled to be low, the video A corresponding to the stereoscopic image a projected from the projector 20 is projected onto the screen 13-1. To do. When the transmittance of the screen 13-2 is controlled to be low, the image B corresponding to the stereoscopic image b projected from the projector 20 is projected onto the screen 13-2. When the transmittance of the screen 13-3 is controlled to be low, the image C corresponding to the stereoscopic image c projected from the projector 20 is projected onto the screen 13-3.

  Here, the control unit 14 continuously switches the screen 13 having a low transmittance at intervals shorter than the time resolution of the human eye, thereby causing the observer 100 to perceive the cross-sectional view to be connected by the afterimage effect, as if the volume It is possible to make it appear as if a three-dimensional image is displayed. That is, when the transmittance of each screen 13 shown in FIG. 5C is controlled at a high speed, as shown in FIG. 5D, the aerial image A ′ of the video A is perceived in the layer in front of the observer 100. Thus, the middle layer can perceive the aerial image B ′ of the video B, and the inner layer can perceive the aerial image C ′ of the video C. In addition, when displaying a three-dimensional image, it is suitable to switch the screen 13 with low transmittance | permeability in the arrangement | positioning order of the screen 13. FIG.

  Next, a modification of the aerial image display system 1 will be described. FIG. 6 is a side view showing an aerial image display system 1 ′ that is a modification of the aerial image display system 1. The aerial image display system 1 ′ includes an aerial image display device 10 a ′, a projector 20, and a video output device 30, a single screen 13, a real object 40 disposed on the back of the screen 13, The projector 20 is disposed on the front surface.

  FIG. 7 is a diagram for explaining the operation of the aerial image display device 10a '. As shown in FIG. 7A, when the control unit 14 controls the transmittance of the screen 13 to be low, the light projected from the projector 20 is reflected and enters the optical element 12. Accordingly, as shown in FIG. 7A, the aerial image A ′ corresponding to the video (object A) projected from the projector 20 is displayed. The display position of the aerial image A ′ is the same as that of the aerial image display device 10 a described above.

  On the other hand, as shown in FIG. 7B, when the projector 20 stops the projection and the control unit 14 controls the screen 13 to have high transmittance, the light reflected by the real object 40 is transmitted through the screen 13. The light enters the optical element 12. Accordingly, as shown in FIG. 7B, the aerial image 40 'corresponding to the real object 40 is displayed behind the aerial image A' by the distance D.

  As described above, the aerial image display devices 10a and 10a ′ according to the first embodiment are disposed outside the housing 11 and the housing 11, and project the projection light from the projector 20, and have variable transmittance. One or more controllable screens (variable transmittance plates) 13 and the light projected on the screen 13 are incident on the screen 11 to form an aerial image inside the housing 11. The position of the aerial image is controlled by controlling the transmittance of the screen 13. Therefore, the aerial image display devices 10a and 10a 'can display aerial images having a plurality of depths. Further, since the movement of the screen 13 can be realized in a pseudo manner only by electrical characteristic control, an actuator for moving the screen 13 mechanically (physically) becomes unnecessary, and the apparatus can be downsized. it can.

  Also, the position of the aerial image can be controlled by arranging a plurality of screens 13 in parallel, lowering the transmittance of one of the plurality of screens 13 and increasing the remaining transmittance. . That is, since the screen can be moved in a pseudo manner by switching the transmittance of the screen 13, the aerial image displayed in the housing 11 can be quickly and discontinuously viewed from the observer 100. Can be moved to. Note that by increasing the number of screens 13, the aerial image can be smoothly moved back and forth.

  Furthermore, an afterimage effect can be obtained by switching the screen 13 having a low transmittance from a plurality of screens at intervals shorter than the time resolution of the human eye. Therefore, it is possible for the observer 100 to perceive an object in which a plurality of layers are overlapped or to perceive a stereoscopic image.

(Second Embodiment)
Next, an aerial image display apparatus according to the second embodiment of the present invention will be described. FIG. 8 is a side view showing a configuration example of an aerial image display system including an aerial image display device according to the second embodiment of the present invention. In the example illustrated in FIG. 8, the aerial image display system 2 includes the aerial image display device 10 b according to the second embodiment of the present invention and a video output device 30. The aerial image display device 10 b includes a housing 11, an optical element 12, and a plurality of displays (transmittance variable plates) 15. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  The video output device 30 is a PC, for example, and controls the display 15 to display video on the display 15.

  The display 15 is a see-through display (see-through display) whose color and transmittance can be controlled in units of pixels or rectangles based on the control of the video output device 30. A plurality of displays 15 are arranged outside the housing 11. Here, an example will be described in which the two displays 15-1 and 15-2 are arranged below the housing 11 when viewed from the observer 100.

  The optical element 12 is a half mirror, for example, and is provided inside the housing 11. The optical element 12 is provided with an inclination of approximately 45 degrees toward the viewer 100, and receives light emitted from the display 15 and reflects the light toward the viewer 100.

  Next, the operation of the aerial image display device 10b will be described with reference to FIG. FIG. 9A is a side view showing a configuration example of the aerial image display system 2 when the aerial image is displayed to the observer 100, and FIG. 9B is a display displayed by the displays 15-1 and 15-2. FIG. 9C is a diagram illustrating an aerial image observed by the observer 100. FIG.

  As shown in FIG. 9B, the video output device 30 displays the object A on the display 15-1 and displays the object B on the display 15-2. At this time, the transmittance of the display 15-1 is controlled so as to display only the object A, and all the pixels other than the pixel displaying the object A are controlled so as to have a high transmittance. In addition, the transmittance of the display 15-2 is controlled so as to display only the object B, and all the pixels other than the pixel displaying the object B are controlled so as to have a high transmittance.

  The optical element 12 receives light emitted from the display 15-1 and reflects the light toward the observer 100. When the display 15-1 is arranged so as to be in contact with the housing 11 without providing a distance, the aerial image A ′ corresponding to the object A is displayed on the housing 11 as shown in FIG. It includes a contact point (base point) between the facing surface of the display 15-1 and the optical element 12, and is displayed on a spatial plane perpendicular to the facing surface.

  The optical element 12 receives light emitted from the display 15-2 and reflects the light toward the observer 100. When the display 15-2 is arranged in a direction away from the housing 11 by the distance D from the display 15-1, as shown in FIGS. 9A and 9C, only the distance D from the aerial image of the object A is obtained. An aerial image of the object B is formed behind.

  As described above, the aerial image display device 10b according to the second embodiment is arranged outside the housing 11 and displays the video input from the video output device 30 with variable transmittance. One or more displays (transmittance variable plates) 15 that can be controlled to the light and the housing 11 are arranged so that light emitted from the display 15 is incident to form one or more aerial images inside the housing 11. The position of the aerial image is determined by the distance between the display 15 and the housing 11. For this reason, in the aerial image display devices 10a and 10a ′ according to the first embodiment, only one aerial image layer can be displayed at a time without using the afterimage effect. The aerial image display device 10b can display a plurality of layers of aerial images on one optical element 12. By increasing the number n of the displays 15, an aerial image having more depth information can be displayed simultaneously.

  Further, the aerial image display device 10b displays the object only on the display 15-1, and then displays the object only on the display 15-2, so that the aerial image display device 10b is similar to the aerial image display devices 10a and 10a ′. Can be moved back and forth as viewed from the observer 100 at high speed and discontinuously.

(Third embodiment)
Next, an aerial image display apparatus according to the third embodiment of the present invention will be described. FIG. 10 is a side view showing a configuration example of an aerial image display system including an aerial image display device according to the third embodiment of the present invention. In the example illustrated in FIG. 10, the aerial image display system 3 includes an aerial image display device 10 c, a projector 20, and a video output device 30. The aerial image display device 10 c includes a housing 11, an optical element 12, and a plurality of displays (transmittance variable plates) 15. The same components as those in the second embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  The video output device 30 is a PC, for example, and controls the display 15 to display video on the display 15. Further, the video output device 30 outputs a video to be displayed on the display 15 to the projector 20.

  In order to clearly display the aerial image, it is necessary to increase the amount of light of the image corresponding to the aerial image. However, when a plurality of displays 15 are arranged in parallel, the display 15 located farther from the housing 11 has a greater optical element. The light incident on 12 is attenuated. Therefore, in the present embodiment, the projector 20 is disposed on the back surface of the display 15 in order to increase the amount of light.

  The projector 20 projects white light or light of the same color as the object on the display 15 in accordance with the shape of the object displayed on the display 15. Thereby, the light quantity which the object displayed on the display 15 emits can be increased.

  The display 15 is a see-through type display (see-through display) in which color and transmittance can be controlled in units of pixels or rectangles. Alternatively, the display 15 can control the transmittance in units of pixels or rectangles, but may not be able to express the color. In this case, the projector 20 projects light of a color that matches the object.

  A plurality of projectors 20 may be provided, and in this case, the amount of light emitted from the display 15 can be further increased by projecting light to the same location. Further, the projector 20 may increase the amount of light projected onto the object of the display as the display is farther from the housing 11.

  Next, the operation of the aerial image display device 10c will be described with reference to FIG. FIG. 11A is a side view showing a configuration example of the aerial image display system 3 in the case where an aerial image is displayed to the observer 100, and FIG. FIG. 11C is a diagram showing an aerial image observed by the observer 100. FIG.

  As shown in FIG. 11B, the video output device 30 displays the object A on the display 15-1 and displays the object B on the display 15-2. At this time, the transmittance of the display 15-1 is controlled so as to display only the object A, and all the pixels other than the pixel displaying the object A are controlled so as to have a high transmittance. In addition, the transmittance of the display 15-2 is controlled so as to display only the object B, and all the pixels other than the pixel displaying the object B are controlled so as to have a high transmittance.

  Furthermore, the projector 20 projects the light on the display 15-1 so as to overlap the object A displayed on the display 15-1. In addition, the projector 20 projects the light on the display 15-2 so as to overlap the object B displayed on the display 15-2. By doing in this way, as shown in FIG.11 (c), the observer 100 can observe a clear aerial image.

  As described above, in the aerial image display device 10c according to the third embodiment, the display 15 displays the video input from the video output device 30, and projects the projection light from the projector 20. Therefore, in the aerial image display device 10c, the width of the dynamic range in which the aerial image can be expressed is widened, and the aerial image can be clearly displayed without being overexposed. In particular, the display 15 preferably projects the projection light of the projector 20 so as to overlap the object being displayed. Further, the light quantity of the aerial image can be easily increased by increasing the number of projectors. Of course, the number of displays 15 may be one, and a clear aerial image may be displayed at the same location.

  Although the above embodiment has been described as a representative example, it will be apparent to those skilled in the art that many changes and substitutions can be made within the spirit and scope of the invention. Therefore, the present invention should not be construed as being limited by the above-described embodiments, and various modifications and changes can be made without departing from the scope of the claims. For example, in the first embodiment, instead of the screen 13, a see-through display 15 capable of controlling the transmittance in units of pixels or rectangles may be used.

1, 1 ', 2, 3, 4 Aerial image display system 10a, 10a', 10b, 10c, 10d Aerial image display device 11 Housing 12 Optical element 13 Screen (variable transmittance plate)
14 Control unit 15 Display (variable transmittance plate)
20 Projector 30 Video Output Device 40 Real Object

Claims (10)

An apparatus for displaying an aerial image in space,
A housing,
One or more transmittance variable plates that are arranged outside the housing and project projection light from the projector, and the transmittance can be variably controlled;
An optical element that is disposed inside the casing and receives light projected on the transmittance variable plate to form an aerial image inside the casing.
The position of the aerial image is controlled by controlling the transmittance of the transmittance variable plate,
An aerial image display device, wherein an entity is disposed on the rear surface of the variable transmittance plate and outside the housing . The aerial image display device according to claim 1, wherein the projector is disposed in front of the transmittance variable plate and outside the casing . A plurality of the transmittance variable plates are arranged in parallel,
The position of the aerial image is controlled by lowering the transmittance of one transmittance variable plate of the plurality of transmittance variable plates and increasing the transmittance of the remaining transmittance variable plates. The aerial image display device according to claim 1, wherein:   The aerial image display device according to claim 3, wherein the transmittance variable plate having a low transmittance is switched among a plurality of plates at an interval shorter than the time resolution of human eyes.   The aerial image display device according to claim 4, wherein the transmittance variable plate having a low transmittance projects different objects.   The spatial image display device according to claim 4, wherein the transmittance variable plate having a low transmittance projects an image corresponding to a stereoscopic image obtained by dividing the stereoscopic image in the depth direction. An apparatus for displaying an aerial image in space,
A housing,
One or more transmittance variable plates that are arranged outside the housing and display the image input from the image output device, and the transmittance can be variably controlled;
An optical element that is disposed inside the casing and receives light emitted from the transmittance variable plate to form one or more aerial images inside the casing;
The position of the aerial image is determined by the distance between the transmittance variable plate and the housing,
An aerial image display device, wherein an entity is disposed on the rear surface of the variable transmittance plate and outside the housing .   The aerial image display device according to claim 7, wherein the transmittance variable plate displays an image input from the image output device and projects projection light from a projector.   The aerial image display device according to claim 8, wherein the transmittance variable plate projects the projection light of the projector so as to overlap an object being displayed. An aerial image display method for displaying an aerial image in a space inside a housing,
Arranging an entity on the back of one or more transmittance variable plates disposed outside the housing;
Projecting projection light by a projector;
Projecting the projection light by the transmittance variable plate;
Incident light projected on the transmittance variable plate by an optical element disposed inside the housing, and forming an aerial image inside the housing;
Controlling the position of the aerial image by controlling the transmittance of the transmittance variable plate;
A method for displaying an aerial image, comprising:

Images