JP2002196280A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device which can perform display without any incompatibility including focusing and change of convergence caused by distance. SOLUTION: The display device capable of observing a displayed image by using a viewer has display devices 3 and 4 which display an image, viewers 1 and 2 for generating a virtual or real image of the image and observing this image, and an image position change mechanism which can change the position of the image by changing the focal distance of the viewers 1 and 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device.

[0002]

2. Description of the Related Art Conventionally, as a method for displaying a stereoscopic image, a binocular stereoscopic method, a real space display method, a holographic method and the like have been proposed.

[0003] The binocular stereoscopic method is also called a stereo method,
This is a method of stereoscopically recognizing an image by giving images with parallax to the left and right eyes. This method includes a method using glasses and a method not using glasses. The left and right images are alternately displayed on a normal television screen, and the left and right images are projected on the left and right eyes by switching shutters provided on the left and right lenses of the glasses in synchronization with the left and right images, thereby providing stereoscopic vision. There is also a method of attaching a lenticular lens to a television screen and projecting the left and right images to the left and right eyes.

On the other hand, the real space display method is also called a volume scanning method, and is a method of moving a planar display physically at a high speed in the depth direction to make it appear as if a three-dimensional object exists there.

The holography method is a method of providing a stereoscopic view by reproducing the wavefront of light actually coming from an object by holography, as is well known.

Further, a device for changing the virtual image position by changing the focal length of a viewer of a head-mounted display has been disclosed for researching depth perception in stereo display. However, an image at one distance is used. . In other words, the display position of the display image is changed to examine the perception based on the relationship with the convergence (the direction in which the left and right eyes look), and it has not been developed to three-dimensional display. (Optical vo
l. 24, no1, p8 (1996)) Japanese Patent Application Laid-Open No. 7-167633 discloses a method for reducing the mismatch between convergence and focus adjustment, in which the convergence and focus adjustment fall within the fusion limit of binocular vision during display. As described above, there has been proposed a method of using a stereo image captured while changing the convergence angle of a stereo camera when capturing a stereo image in advance.

[0007]

In the binocular stereoscopic method, that is, the stereo method, a sense of distance is generated due to a change in convergence, but since the focus is constant irrespective of the distance, there is a disadvantage that the viewer tends to be tired when viewing an image for a long time. is there. Also, the view of nature is impaired. In the hologram method, since the wavefront actually coming from the three-dimensional structure is visually observed, ideally, the conditions are the same as those of the real thing. And the image becomes dirty. Also,
It is not practical because it has drawbacks such as the inability to display moving images of the hologram and difficulty in colorization. The real space display method is not practical because it requires moving the flat display device at high speed.

In Japanese Patent Application Laid-Open No. Hei 7-167633, it is necessary to perform photographing while calculating the fusion range when displayed at the time of photographing, and it is not possible to photograph all subjects under the condition that they are within the fusion range. However, there is a disadvantage that the range of the subject cannot be largely separated from the position of the actual display image of the display device.

The present invention has been made in view of such a problem, and an object of the present invention is to provide a display device capable of performing a display without a sense of incongruity including a focus adjustment according to a distance and a change in convergence. To provide.

[0010]

According to a first aspect of the present invention, there is provided a display device capable of observing a displayed image with a viewer, comprising: a display device for displaying an image; It has a viewer for generating a virtual image or a real image and observing the image, and an image position changing mechanism capable of changing the position of the image by changing the focal length of the viewer. Of course, the position of the viewer may be moved in the optical axis direction.

According to a second aspect of the present invention, there is provided a display device capable of observing a displayed image with a viewer. The display device displays an image, and generates a virtual image or a real image of the image and observes the image. And an image position changing mechanism that can change the position of the image by moving the position of the display device in the optical axis direction.

According to a third aspect of the present invention, in the display device according to the first or second aspect, the display device can switch and display a plurality of images, and the image position changing mechanism switches the images. , The image position is changed to a predetermined image position for each image.

According to a fourth aspect of the present invention, in the display device according to the third aspect, the switching of the images is performed at such a speed that an afterimage remains in the eyes, and the observer has the predetermined image position. Each image is configured to be superimposed and observed.

According to a fifth aspect of the present invention, in the display device according to the third or fourth aspect, an image displayed on the display device is divided from an original image according to a distance to each subject in the image. Multiple distance-based images created by
The predetermined image position for each image is an image position based on the distance to the subject in the image for each distance.

[0015] In a sixth aspect of the present invention, the first, second, third,
In the fourth or fifth invention, there is a pair of the viewers corresponding to the left and right eyes of the observer, and the image corresponding to the right viewer and the image corresponding to the left viewer correspond to convergence. The left and right images are shifted from each other by a distance.

According to a seventh aspect, in the display device according to the first to fifth or sixth aspects, display is performed by changing a display distance according to a display magnification of the display device.

According to an eighth aspect, in the display device according to the first to sixth or seventh aspects, the viewer includes a variable focus mirror.

According to a ninth aspect, in the display device according to the first to seventh or eighth aspects, the viewer includes a variable focus lens.

According to a tenth aspect, in the display device according to the first to eighth or ninth aspects, the display device comprises:
Can be worn on the head or face.

According to an eleventh aspect of the present invention, in the display device according to the first aspect, there is a pair of viewers corresponding to the left and right eyes of the observer, and one display device corresponding to the left and right eyes. The images are displayed alternately at different distances.

According to a twelfth aspect, in the display device according to the first aspect, the viewer is provided in a pair corresponding to the left and right eyes of the observer, and the display device is provided as a single unit corresponding to the left and right eyes. The stereoscopic images are alternately displayed, and the image position of the viewer is adjusted to a distance corresponding to the distance of the observed object determined by the parallax of the stereo images.

[0022]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(First Embodiment) FIG. 1 is a view showing a configuration of a display device according to a first embodiment of the present invention. A pair of display devices 3 and 4 for displaying an image and the pair of display devices 3 are shown. And a pair of viewers 1 and 2 that are arranged corresponding to the display devices 3 and 4, respectively, and that observe images displayed by the display devices 3 and 4. The observer can observe the left and right stereo images 5 and 6 by looking through the display devices 3 and 4 through the viewers 1 and 2 with the left and right eyes 50-1 and 50-2, and use these as stereoscopic images. I can recognize.

In the present embodiment, the display devices 3 and 4 can be moved in the optical axis direction by an image position changing mechanism (not shown). Can be changed from short distance to infinity. Further, the focal lengths of the viewers 1 and 2 may be changed instead of moving the display devices 3 and 4.

As described above, according to the present embodiment, when the observer observes the virtual image or the real image generated by the viewer 1, the image position is changed by the image position changing mechanism (between the viewers 1 and 2 and the stereo images 5 and 6). Since the distance can be changed, the image can be observed at a desired image position of the observer. For example, it is possible to present an image reflecting the sense of distance in the real world, such as moving the image position far in the case of a mountain image and moving the image position close in the case of a human image.

Next, a plurality of subjects 52, 53, 54 existing at different distances as shown in FIG. 2 are photographed by known stereo cameras 7, 8, and left and right images 9, 1 are taken as original images.
When 0 is obtained, this is decomposed (divided) into images for each distance based on distance information to the subject, and FIG.
3 (d). FIG. 3A shows left and right images taken by the stereo cameras 7 and 8, and FIG.
(C) and (d) are images for each distance decomposed for each distance based on the distance information. The image for each distance is displayed in synchronization with the image position of the display device corresponding to the distance. As a result, it is possible to provide a three-dimensional display without a sense of incongruity that includes changes in focus adjustment and convergence depending on the distance. The distance information may be obtained from a stereo image, or other information may be used.

The display devices 3 and 4 are shown in FIG.
The plurality of images shown in (c) and (d) can be switched and displayed, and the image position changing mechanism changes the image position for each image for each distance in synchronization with the switching of the image. Change to a distance corresponding to the distance to. As a result, the subject of the original image can be presented at a distance corresponding to the distance to the subject. That is, the images can be presented to the observer with a suitable perspective for each image.

Further, if the switching of the images is performed at such a speed that an afterimage remains in the eyes of the observer, the observer observes the images having the image positions in a superimposed manner. As a result, the image at the near image position and the image at the far image position are superimposed and displayed.

The displayed image is not always displayed at the same magnification as the real world. For example, FIG. 4A shows a case where the image is displayed at the same magnification as the real world, but a natural stereoscopic effect (focus adjustment and convergence are the same as the real image) is obtained. However, FIG.
For example, when the display position is displayed at the same distance as the real image, for example, when the display magnification is displayed at a half of the real world as in (b), the display position is recognized as a solid having a depth larger than the actual one, giving an unnatural feeling. (Focus adjustment and convergence are different from the actual image).

In this case, as shown in FIG. 5B, if the display distance is also reduced to one half, the state becomes the same as simply looking at the miniature of FIG. You can get it. However, at this time, the congestion also changes about twice,
The display position of the image for each distance to be displayed must be slightly shifted left and right and displayed (FIGS. 6A and 6A).
(B)). At this time, since a lack portion occurs in the stereo image taken in advance, the lack is compensated by using information of both the left and right images.

By the effect of the convergence and the effect of the image position according to the subject distance, it is possible to present an image closer to the real sense of distance.
The images corresponding to the left and right viewers are preferably based on images captured in stereo, but are not limited thereto. CG may be used. Alternatively, one display device may be viewed by two viewers, a shutter may be provided for each viewer, and left and right images may be displayed alternately in synchronization with opening and closing of each shutter.

(Second Embodiment) Hereinafter, a second embodiment of the present invention will be described.

FIG. 7 is a diagram showing a configuration of a display device according to a second embodiment of the present invention, and shows a part of an optical system and an electric system of the display device that can be worn on the head or face. The observer 50 displays the image displayed on the flat panel display (FPD) 21 with the free-form surface prism 22 and the varifocal mirror 2.
3 is a display device that allows an image displayed on the FPD 21 to be viewed as an enlarged aerial image (virtual image) when viewed through a viewer configured with the viewer 3.

A conventional head mounted display (HMD) or face mounted display (FM)
The display device D) does not have a variable focus mirror. Usually, one set of these optical systems is provided for each of the left and right eyes. We usually look at the three-dimensional world with both the left and right eyes. We adjust the focus of the eyes (without consciousness) according to the distance to the object (subject in the image), and also according to the distance of the object. This changes the viewing direction (convergence) of the left and right eyes (without being conscious). As described in the related art, there is a stereo display as a typical three-dimensional display method. This allows the left and right eyes to feel a stereoscopic effect by independently giving left and right images taken by a stereo camera.

In the conventional HMD / FMD, the left and right images can be given independently to the left and right eyes, but the focus adjustment and the convergence change cannot be given according to the distance of the object. Looking at the images, he was tired and uncomfortable. In this embodiment, the position of the object can be displayed from infinity to a short distance by the variable focus mirror.

FIG. 8 illustrates this principle. If the focal length of the viewer 31 is f and the FPD 32 is placed at a position away from the viewer 31 by f, the FPD 32 is enlarged by the viewer 31 and the position of the enlarged image becomes infinity. Assuming that the distance between the viewer 31 and the FPD 32 is D and the position of the virtual image 33 formed by the viewer, that is, the distance from the viewer 31 is L, f = DL / (LD). When the focal length of the viewer 31 is 30 mm and the FPD 32 is placed at a position 30 mm away from the viewer 31, an image displayed on the FPD 31 is generated at infinity. When displaying an object at a distance of 300 mm, L = 300 to f = 33.3.
It can be understood that the focal length of the viewer 31 should be adjusted to 33.3 mm by adjusting the varifocal mirror. That is, by changing the focal length of the viewer 31 from 30 mm to 33.3 mm by the varifocal mirror, the distance from infinity to 3
The position of the virtual image 33 can be changed to a short distance of 00 mm. Therefore, the observer will need to adjust the focus of the eye accordingly, and will perform the focus adjustment (without consciousness).

The displayed image will be described in more detail. In this embodiment, an image for display uses an image obtained in a stereo system. A stereo image is placed at a certain distance B away from the camera and is composed of two cameras that photograph the same direction (the distance corresponding to the interpupillary distance is B). At this time, the distance L
The convergence φ when looking at the object (subject) is tan (φ /
2) = B / (2L). It is independent of the focal length of the imaging lens. At this time, assuming that the display magnification in the viewer is the same, the interval between the left and right eyes (interpupillary distance) is E, and an unnatural image is obtained unless the convergence is corrected to E / B times. Of course, if the display magnification is 1 / C, the convergence is further increased by C times.
If the display distance is not reduced to 1 / C, an unnatural three-dimensional image will be obtained. In order to display a three-dimensional image with a natural sensation, the above-described adjustment of the display magnification, the adjustment of the display distance, and the adjustment of the image for each distance in the left and right direction due to the change in convergence are performed.

The procedure of the above-described image processing will be described with reference to FIGS. 9 (a) and 9 (b). FIG. 9A shows left and right images taken by a stereo camera. The distance from a stereo image taken by a camera having two imaging lenses corresponding to the left and right eyes to a subject (object) is obtained for each pixel. This is a known process that is usually performed using a correlation method or the like. Since a distance is obtained for each pixel, a distance image can be created.

The distance image shown in FIG. 9B is prepared according to the line of sight of the left eye. In the present embodiment, it is not always necessary to create this distance image. Since the distance of each pixel has been clarified, an image for each distance is generated next. The number of images for each distance is determined depending on how many images for each distance are displayed in the distance direction.

FIG. 10 is an explanatory diagram of how to determine the required number of images for each distance and the division of distance when it is assumed that the eye can distinguish a certain change in the convergence angle. Assuming that the parallax of θ is known, the convergence of n pieces is nθ / 2, and the position Xn of the image for each distance is Xn = (b / 2) / tan (n), where b is the width of the human eye.
θ / 2). If the interpupillary distance b = 80 mm and n = 50, X50 = 300 mm, X49 = 306 mm, X
48 = 313 mm,... X25 = 602 mm,.
5808 mm is obtained. (X0 = infinity) θ = 0.3
Degrees. In this way, the required number of images for each distance and the display distance can be obtained.

In FIG. 9C, for the sake of simplicity, three distance images of a short distance, a medium distance, and a long distance are used. An image for each distance is created at the closest distance from the distance information for each pixel. In this example, people are near-range images, houses are medium-range images,
Mountains apply to long-range images. For the left eye, an image for each distance for the left eye is created from the image for the left eye captured by the camera for the left eye, and similarly for the right eye, an image for each distance for the right eye is created from the image for the right eye. However, as described above, when the interpupillary distance of the imaging camera is different from that of a human (viewer), or when the display magnification is not equal, the convergence is different from the convergence of the state captured by the stereo camera. In addition, it is necessary to newly create a lateral shift of the image at each distance according to the convergence angle.

At this time, the farther the image of each distance is, the more the shadow of the subject in front increases. Therefore, the left and right stereo images are used to recover the image as much as possible. If the left and right images are used, an image that can be viewed almost from the viewing direction can be recovered. This is because the change in convergence depending on the distance is large, but the position of the viewing eye does not move. In other words, when viewing the image, it is assumed that the observation is performed from the position where the eyes are located, so that the shadow portion is not originally visible. Note that, in the case of the above-described composite image, it is necessary to remove a portion that is shaded by overlapping according to the convergence.

When the stereo camera has an eye width of m times the viewer, if the reduction ratio of the displayed image is 1 / m,
Since there is no change in convergence, complicated image processing required by the convergence change becomes unnecessary. At this time, if the display magnification is set to 1 / m, a three-dimensional image can be displayed without losing the view of nature.

FIG. 7 shows one of the left and right sets of the display device. The image data 27 for each left and right distance is displayed in synchronization with the change of the display distance by the varifocal mirrors 23 and 24 by the synchronization signal generation circuit 26. . The display circuit 25 simultaneously shifts the image data 27 for each distance according to a change in the display distance and displays the image data 27 on the FPD 21. In order to prevent flicker, it is necessary to display at least 30 Hz. In order to display the image data 27 for each distance at 30 Hz, in the case of this embodiment, since there are 51 distances, 30 × 50 = 1500 Hz
To display the image data 27 for each distance on the FPD 21.

By displaying the change of the convergence as described above, the convergence adjustment is required, and the observer adjusts the convergence (without consciousness), so that the three-dimensional image can be viewed more naturally. I can do it.

The focal length of the viewer can be changed,
Changing the position of the display device changes the size of the image observed through the viewer. In order to cancel or reduce this change, it is preferable to appropriately adjust the size of the image displayed on the display device.

The above-described embodiment is summarized as follows.

1. By providing a display device and means for changing the focal length of the viewer so as to display an image including distance information and a viewer looking into the display device at a position corresponding to the distance, the three-dimensional image information can be focused by distance. And a display device capable of performing display including a change in congestion.

2. Includes means for changing the focal length of the viewer so that the image is divided into a plurality of images for each distance and displayed at a position corresponding to the distance, so that the three-dimensional image information includes focus adjustment by distance and change in convergence. Provided is a display device capable of performing display on a display device.

3. Two viewers corresponding to the left and right eyes, and by providing a means for shifting the image displayed on the display device in the left and right opposite directions by a distance corresponding to the convergence, to focus the three-dimensional image information by distance and to adjust the convergence. Provided is a display device capable of displaying a change.

4. Provided is a display device which can easily display three-dimensional image information including a focus adjustment based on a distance and a change in convergence, since a means for changing a focal length of a viewer is a variable focus mirror.

5. Provided is a display device which can easily display three-dimensional image information including a focus adjustment according to a distance and a change in convergence, since a means for changing a focal length of a viewer is a variable focus lens.

6. Provided is a convenient display device that displays three-dimensional image information including focus adjustment by distance and changes in convergence by being attachable to the head or face.

7. Provided is a display device that displays a natural three-dimensional image by changing a display distance according to a magnification of a display image.

(Third Embodiment) FIGS. 11 and 12
A third embodiment of the present invention will be described with reference to FIG. FIG.
, An image is projected alternately on the left and right on the screen 100, and in synchronization therewith, the variable focus optical systems (for example, liquid crystal lenses) 101-1, 101-2 and the shutter 10
The shutters 102-1 and 102-2 of the stereoscopic glasses constituted by 2-1 and 102-2 are alternately opened and closed. At that time,
The focus of the variable focus optical systems 101-1 and 101-2 is adjusted in accordance with the distance of the image for each distance projected on the screen 100, and the virtual image position is adjusted to the distance of the image for each distance.

Assuming that the distance from the observation position (the position of the stereoscopic glasses) to the screen 100 is 10 m, and the change of the displayed distance is from 3 m to infinity from the observation position, the focal points of the variable focus optical systems 101-1 and 101-2. The distance needs to be changed from -4.3 m to infinity (no lens action) to 10 m. When the focal length is -4.3 m (concave lens action), the focal point is 3 m ahead.

As the focal length is increased in the negative direction, the focus becomes gradually longer. Focal length-
When the distance is 10 m, the focus is 5 m ahead.
Further, when the focal length becomes minus infinity (there is no lens effect), the image is naturally focused on the screen position of 10 m. When the focal length is 10 m, the camera focuses on infinity.

Thus, the screen position is 10 m
Although it is fixed earlier, the image for each distance can be displayed from 3 m ahead to infinity. In order to eliminate flickering during observation, an image display speed of usually about 30 Hz is required. If each of the left and right images is displayed at 30 Hz, a display speed of 30 × 5 × 2 = 300 Hz is required when the number of images per distance is five.

As shown in FIG. 12, when the left and right images are alternately displayed using the two projectors 201-1 and 201-2, the display speed can be reduced by half to 150 Hz. Here, a display device includes the projectors 201-1 and 201-2 and the screen 200. Therefore, a case where two projectors (here, 201-1 and 201-2) are used to display one screen (here, 200) is referred to as one display device. Note that a display device such as an LCD, a PDP, or a CRT may be used instead of the screen 200.

Further, when projecting a normal stereo image (not a distance image), the distance to an object which is considered to be seen by the observer, for example, the distance to the closest object (which can be calculated from the parallax of the stereo image). There is also a method of adjusting the focus of the variable focus optical system so that the virtual image position is adjusted. When a single observer system is configured, the focus adjustment of the varifocal optical system is performed by using the line-of-sight detection means, detecting the position on the image viewed by the observer, and calculating the parallax at that position. Thus, an image can be displayed at a distance from the place where the observer is looking.

[0061]

According to the present invention, it is possible to provide a display device capable of performing a display without a sense of incongruity including a focus adjustment according to a distance and a change in convergence.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a display device according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating how a plurality of subjects existing at different distances are photographed by a known stereo camera to obtain left and right images.

FIG. 3 is a diagram showing a state where left and right images are decomposed into images for each distance.

4A is a diagram illustrating an example in which a subject is displayed at the same magnification as in the real world, and FIG. 4B is a diagram illustrating an example in which the subject is displayed at a display magnification of half that of the real world.

FIG. 5 is a diagram for explaining a method of obtaining a natural three-dimensional effect when a display image is not displayed at the same magnification as the real world.

FIG. 6 is a diagram showing a state in which the display position of each distance-based image to be displayed is slightly shifted left and right, and is displayed.

FIG. 7 is a diagram illustrating a configuration of a display device according to a second embodiment of the present invention.

FIG. 8 is a diagram for explaining the principle of displaying the position of an object from infinity to a short distance by using a variable focus mirror.

FIG. 9 is a diagram for explaining a method of displaying a three-dimensional image having a natural feeling.

FIG. 10 is an explanatory diagram of how to determine the required number of images for each distance and how to classify distances when it is assumed that the eye can distinguish a certain convergence angle change.

FIG. 11 is a diagram (part 1) for explaining a third embodiment of the present invention;

FIG. 12 is a diagram (part 2) for explaining the third embodiment of the present invention;

[Explanation of symbols]

 1, 2 Viewer 3, 4 Display Device 5, 6 Stereo Image 7, 8 Stereo Camera 9 Left Image 10 Right Image 21 FPD (Flat Panel Display) 22 Free-Form Surface Prism 23 Variable Focus Mirror 24 Variable Focus Mirror 25 Display Circuit 26 Synchronization Signal Generation circuit 27 Left and right image data for each distance 50 Observer 50-1, 50-2 Eyes of observer 52, 53, 54 Subject 100 Screen 101-1, 101-2 Variable focus optical system 102-1, 102-2 Shutter 200 screen 201-1, 201-2 Projector 203 3D glasses

Claims (12)

[Claims] 1. A display device capable of observing a displayed image with a viewer, a display device for displaying the image, a viewer for generating a virtual image or a real image of the image, and observing the image; An image position changing mechanism capable of changing the position of the image by changing the focal length of the display device. 2. A display device capable of observing a displayed image with a viewer, a display device for displaying the image, a viewer for generating a virtual image or a real image of the image, and observing the image; A display device, comprising: an image position changing mechanism that can change the position of the image by moving the position of the device in the optical axis direction. 3. The image display device according to claim 2, wherein the display device is capable of switching and displaying a plurality of images, and wherein the image position changing mechanism changes a predetermined image position for each image in synchronization with the switching of the images. The display device according to claim 1 or 2, wherein 4. The image switching is performed at such a speed that an afterimage remains in the eyes, and the observer observes each image having the predetermined image position in a superimposed manner. The display device according to claim 3, wherein: 5. An image displayed on the display device,
A plurality of distance-based images created by dividing the original image according to the distance to each subject in the image, and the predetermined image position of each image is based on the distance to the subject in each of the distance-based images. The display device according to claim 3, wherein the display device is an image position. 6. The viewer has a pair corresponding to the left and right eyes of the observer. The image corresponding to the right viewer and the image corresponding to the left viewer are mutually separated by a distance corresponding to convergence. 2. The image according to claim 1, wherein the image is shifted in the left-right direction.
The display device according to 2, 3, 4 or 5. 7. According to a display magnification of the display device,
The display according to claim 1, wherein the display distance is changed.
The display device according to 2, 3, 4, 5, or 6. 8. The display device according to claim 1, wherein the viewer includes a variable focus mirror. 9. The display device according to claim 1, wherein the viewer includes a variable focus lens. 10. The display device according to claim 1, wherein the display device can be mounted on a head or a face.
The display device according to 5, 6, 7, 8 or 9. 11. A viewer according to claim 1, wherein the viewer includes a pair of viewers corresponding to the left and right eyes of the observer, and the display device alternately displays an image for each distance corresponding to the left and right eyes. The display device according to 1. 12. The viewer includes a pair of viewers corresponding to the left and right eyes of the observer, and the display device is configured to alternately display stereo images corresponding to the left and right eyes by one.
The display device according to claim 1, wherein an image position of the viewer is adjusted to a distance corresponding to a distance of the object to be observed determined by the parallax of the stereo image.