JPH09329763A - Stereoscopic image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simultaneously produce images having a plurality of viewpoints by disposing an optical element for changing the advancing direction of a light in the full surface or the back surface of each pixel constituting a spatial optical modulation element. SOLUTION: Fresnel lens 14 is disposed in front of light sources 12A to 12C and the image of a light emitted from each of the light is formed in the vicinity of the viewpoint position of an observer positioned in the front side. A light emission controller 13 causes the first to the third light sources 12A to 12C to emit lights in sequence. An image selector 18 selects, each time a light source number 17 currently emitting a light is inputted, two from six parallax images supplied from a six lens camera 11 based on this light source number 17. A LCD 15 displays a parallax image corresponding to a lighting light source among a plurality of light sources. Further, the light of the first light source 12A is divided by a prism 16 and two real images 21A and 21B are formed in the left and right sides of the real image positions of the first light source 12A having no prism 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stereoscopic image display device capable of stereoscopic viewing without special stereoscopic glasses.

SUMMARY OF THE INVENTION According to the present invention, two images (for right eye and left eye) out of a large number of parallax images are observed by an observer without special glasses (hereinafter referred to as stereoscopic glasses). The present invention relates to a multi-eye stereoscopic image display device that is incident on the left and right eyes, and by arranging an optical element such as a prism that changes the traveling direction of light on the front surface or the back surface of each pixel that constitutes the spatial light modulation element, The present invention realizes a time-division multi-view stereoscopic image display device capable of generating multi-viewpoint images even when a plurality of real images of a light source are present and a spatial light modulator having a slow response speed is used. .

[0003]

2. Description of the Related Art As a conventional example of a multi-view stereoscopic image display device that enables stereoscopic viewing without the need for stereoscopic glasses, for example, the device shown in FIG. 7 is known.

As shown in FIG. 7, this stereoscopic image display apparatus is composed of a first camera 101A, a second camera 101B, a third camera 101C, and a fourth camera 101D, and shoots a subject from four different directions. A four-lens camera 101 that generates one parallax image, a spatial multiplexing device 103 that multiplexes four parallax images 102 obtained from the four-lens camera 101 in a vertical stripe shape, and the spatial multiplexing device 1
03 liquid crystal display (LC
D) 104 and a lenticular lens 105 having a width slightly narrower than the four pixels of the LCD 104. The LCD 104 is illuminated with diffused light from the back. Note that in FIG. 7, the number of lenses forming the lenticular lens 105 is illustrated as two in order to facilitate understanding, but in reality, the cameras 101A to 101 are used.
A sufficient number (hundreds to thousands) to display each image of D is required.

In the above structure, the first camera 101A
The image captured by the
The images are displayed at D and 104H, and are imaged at the position of point P _A by the individual lenses 105A and 105B that form the lenticular lens 105. Similarly, the image captured by the second camera 101B is the pixel 104 of the LCD 104.
C, 104G and the lenses 105A, 1
The image is formed at the position of the point P _B by 05B. Further, the image captured by the third camera 101C has pixels 104B, 1
It is imaged on the point P _C is displayed on the 04F, image fourth camera 101D have taken is imaged point P _D with the display pixel 104A, the 104E. Where point P _B
When observed in the vicinity of, as shown in FIG. 7, only the light emitted from the pixels 104C and 104G having an image forming relationship with the point P _B can be seen.
Since the image taken at is displayed, as a result, the point P
_In the vicinity of _B , the image taken by the second camera 101B can be seen as it is. Similarly, in the vicinity of the points P _A , P _C , and P _D , the first camera 104A and the third camera 1 respectively.
Images captured by 04C and the fourth camera 104D are directly visible. If the distance between the points P _A and P _D is less than about 65 mm between the human eyes, the left and right eyes see images taken by different cameras, and this is observed as a stereoscopic effect. .

[0006]

However, according to the above conventional example, when the number of viewpoints is increased, the LCD 10
It is necessary to reduce the pitch of one pixel displayed on the screen 4 in inverse proportion to the number of viewpoints. Since the pitch of the LCD 104 cannot be made smaller than a certain amount due to the manufacturing limit, it is difficult to realize a multi-view stereoscopic display device having tens of viewpoints. Moreover, in this case, since the resolution of the lenticular lens 105 arranged on the front surface of the LCD also needs to correspond to the pixel pitch of the LCD, the number of viewpoints cannot be increased from this aspect.

The present invention has been made in view of the above circumstances, and an object thereof is a stereoscopic image display which enables stereoscopic viewing by a plurality of observers with a simple device configuration without wearing stereoscopic glasses. To provide a device.

[0008]

In order to achieve the above-mentioned object, the invention of claim 1 is directed to a plurality of light sources which are sequentially blinking, and an imaging lens for forming the light of these light sources in the vicinity of the viewpoint of the observer. And a spatial light modulator which is disposed on the opposite side of the light source with the imaging lens interposed therebetween and displays a parallax image according to the light source that is turned on among the plurality of light sources, and the spatial light modulator. And an optical element which is arranged close to the front surface or the back surface of each pixel forming the element and which changes the traveling direction of light.

According to the above arrangement, since the optical element for changing the traveling direction of light is arranged on the front surface or the back surface of each pixel constituting the spatial light modulation element, the optical element is turned on at the moment when one light source is turned on. When there is no element, there is only one real image due to the lens of the light source, but when there is this optical element, there can be multiple real images due to the lens of the light source because the traveling direction of light can be changed by the optical element. You can Thereby, an image having a plurality of viewpoints can be generated at one time, and an image of a larger number of viewpoints can be generated by time division by sequentially changing the position of the light source that emits light.

According to a second aspect of the present invention, in the stereoscopic image display apparatus according to the first aspect, the optical element that changes the traveling direction of the light is a prism.

According to a third aspect of the invention, in the stereoscopic image display apparatus according to the first aspect, the optical element that changes the traveling direction of the light is a diffraction grating.

When an optical element according to claim 1 is used, which does not have an image forming action and has a property of simply changing the traveling direction of light, the size of the real image of the generated light source is all the light source. Can be set to a constant multiple of the size of. A prism or a diffraction grating is suitable as an element for this purpose.

According to a fourth aspect of the present invention, in the stereoscopic image display apparatus according to the first aspect, the optical element that changes the traveling direction of the light is a part of a single lens.

According to the above arrangement, when the size of the light source is small, there is no practical problem even if an optical element having an image forming function, that is, a lens such as a concave lens is used. When this lens is used, the real image of the light source is blurred and spreads,
If the spread real images are arranged in the vicinity of the observer without a gap, the observer can freely move the viewpoint and observe the stereoscopic image.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

<First Embodiment> FIG. 1 is a block diagram showing a first embodiment of a stereoscopic image display apparatus according to the present invention.

The stereoscopic image display apparatus shown in FIG. 1 is a stereoscopic body without 6-eye glasses in which parallax images of 6 eyes are 3 multiplexed on the time axis and 2 in the horizontal direction of the space for a total of 6 multiplexed (3 × 2 multiplexed). The image display device includes a first camera 11A and a second camera 11
B, a third camera 11C, a fourth camera 11D, a fifth camera 11E, and a sixth camera 11F, and a six-eye camera 11 that captures a subject from six different directions to generate six parallax images, and three light sources. , That is, the first light source 12A,
The second light source 12B, the third light source 12C, a light emission control device 13 that controls the first light source 12A to the third light source 12C to sequentially blink, and the light sources 12A to 12C arranged in front of the light sources 12A to 12C. A Fresnel lens 14 for focusing the light emitted from the image near the viewpoint of an observer located in front, and a liquid crystal display (LCD) as a spatial light modulator arranged between the Fresnel lens 14 and the observer. 15 and a prism 16 (prisms 16A to 1) that is arranged close to the front side of the LCD 15 and that changes the traveling direction of light for each pixel 15A to 15H of the LCD 15.
6H).

Further, this stereoscopic image display device selects any two parallax images from the six parallax images of the six-lens camera 11 based on the light source number 17 emitted from the light emission control device 13. The image selector 18 and the selected parallax images 19A and 19B are pixel-interleaved multiplexed,
That is, a spatial multiplexing device 20 is provided, which generates a spatially multiplexed image on the screen by alternately switching the input two parallax images 19A and 19B for each pixel and supplies the image to the LCD 15.

Each of the light sources 12A to 12 in this embodiment.
The 2Cs are each formed in a vertically long stripe shape and are arranged side by side on a plane perpendicular to the optical axis of the Fresnel lens 14 with appropriate intervals. The LCD 15 is arranged close to the front surface of the Fresnel lens 14. 21A to 21F in the figure indicate the positions of the real images of the light sources 12A to 12C.

Next, referring to FIG. 2, light sources 12A to 12A
The operation of this embodiment will be described focusing on the blinking of C and the operation of the image selector 18.

First, the light emission control device 13 has three light sources 1.
Of the 2A to 12C, only the rightmost first light source 12A is caused to emit light, and the second light source 12B and the third light source 12C are put into the extinguished state (FIG. 2A). At the next time, the second central light source 12
Only B is emitted, the first light source 12A is extinguished, and the third light source 12C is kept extinguished (FIG. 2 (b)). At the next time point, only the leftmost third light source 12C is caused to emit light, and the first light source 12A and the second light source 12B are turned off (FIG. 2 (c)). Similarly, from the first light source 12A to the third
After sequentially emitting light up to the light source 12C, the first light source 1
The process of sequentially emitting light from 2A to the third light source 12C is repeated. At this time, the light source number 17 currently emitting light is sequentially supplied to the image selector 18.

When the light source number 17 is sequentially inputted, the image selector 18 receives the light source number 17 and then the six-lens camera 11
2 are selected from the 6 parallax images supplied from That is, as shown in FIG. 2D, the first light source 12
When A is emitting light, the images of the first camera 11A and the second camera 11B are selected, and when the second light source 12B is emitting light, the images of the third camera 11C and the fourth camera 11D are selected. Similarly, the images of the fifth camera 11E and the sixth camera 11F are selected while the third light source 12C is emitting light. The parallax images 19A and 19B selected by the image selector 18 are supplied to the spatial multiplexing device 20.

As described above, the two parallax images 19A and 19B input to the spatial multiplexing device 20 are the first camera 11 and the parallax images 19A and 19B.
The combination of A and the second camera 11B, the third camera 11
There are three types: a combination of C and the fourth camera 11D, and a combination of the fifth camera 11E and the sixth camera 11F. This is equal to the number of states 3, which of the three light sources 12A to 12C is emitting light. In the spatial multiplexing device 20, the parallax image captured from the left side of the two input parallax images 19A and 19B is displayed on the LCD 15.
The other parallax image (parallax image captured from the right position) displayed on the upper pixels 15A, 15C, 15E, and 15G is simultaneously displayed on the pixels 15B, 15D, and 1 on the LCD 15.
The two parallax images are pixel interleaved and multiplexed so as to be displayed on 5F and 15H. That is, as shown in FIG. 3, when the first light source 12A is emitting light, the LCD 15
The image a of the first camera 11A is displayed on the pixels 15A, 15C, 15E, and 15G of
The image b of the second camera 11B is displayed on 15D, 15F, and 15H. When the second light source 12B is emitting light, the pixels 15A, 15C, 15E,
The image c of the third camera 11C is displayed on 15G, and the pixels 15B, 15D, 15F, and 15H are
The image d of the fourth camera 11D is displayed. In addition, the third
When the light source 12C is emitting light, the pixel 1 of the LCD 15
The fifth camera 11 is provided on the 5A, 15C, 15E, and 15G.
While the image e of E is displayed, the pixels 15B, 15D,
An image f of the sixth camera 11F is displayed on 15F and 15H. As described above, the parallax image 19 corresponding to the light emission of the light sources 12A to 12C is displayed on each adjacent pixel of the LCD 15.
A and the parallax image 19B are displayed alternately, and this is repeated.

Next, referring to FIG. 4, the rightmost first light source 12
The image formation of the real images 21A and 21B of the light source when A is emitting light and what kind of image is observed at the image formation positions of the real images 21A and 21B will be described. FIG. 4A shows prisms 16A and 16A of the light emitted from the first light source 12A.
C, 16E, 16G, FIG. 4B shows prisms 16B, 16 of the light emitted from the first light source 12A.
Focusing on those passing through D, 16F, and 16H, they are shown separately for the sake of clarity.

As shown in FIG. 4A, when the prism 16 is not provided at all, the real image by the Fresnel lens 14 of the first light source 12A can be located at the point P. However, since the traveling direction can be actually changed by the prisms 16A, 16C, 16E, and 16G, the first light source 12A forms an image at the position of the real image 21A. The light observed at the position of the real image 21A is the LCD
Since the light intensity is modulated by the 15 pixels 15A, 15C, 15E, and 15G, and the image input to these pixels is the image of the first camera 11A, the first camera is located at the position of the real image 21A. The image of 11A is observed.

Next, as shown in FIG. 4B, the first light source 12A is emitted and the prisms 16B, 16D, 16F, 1 are emitted.
The light passing through 6H is reflected by these prisms 16B, 16D, 1
The traveling direction is changed by 6F and 16H, and the real image 21B
Image at the position. The light observed at the position of the real image 21B is the pixels 15B, 15D, 15F, 15H of the LCD 15.
The intensity of light is modulated by
Since the images input to B, 15D, 15F, and 15H are images of the camera 11B, the image of the camera 11B is observed at the position of the real image 21B.

As described above, the light from the first light source 12A is distributed by the prism 16, and two real images 21 are provided on the left and right of the real image position P of the first light source 12A when the prism 16 is not provided.
A and 21B can be generated, and images of two different cameras 11A and 11B can be observed at this real image position.

Instead of the first light source 12A, the second light source 12
When B is made to emit light, as in the case described above, the second light source 12
The light of B is distributed by the prism 16 and the prism 1
2 to the left and right of the real image position Q of the second light source 12B when there is no 6
Two real images 21C and 21D can be generated. At this time, since the image selector 18 has selected the third camera 11C and the fourth camera 11D, the images of the two different cameras 11C and 11D can be observed at the position of this real image.

Similarly, when the third light source 12C is emitting light, the images of two different cameras 11E and 11F can be observed at the positions of the real images 21E and 21F.

Here, the real images 21A to 21A of these six light sources.
If the pitch of 21F is set to be less than about 65 mm between the human eyes, the left and right eyes of the human will see images taken from different directions, which can be viewed as a stereoscopic effect.

In order to realize an n-eye stereoscopic image display device without the prism 16 described above, the response speed of the LCD 15, which is a spatial light modulator, is required to be 60 × n hertz per second. For example, when trying to realize a 20-eye stereoscopic image display device, the response speed of the LCD 15 becomes 1200 Hz / sec, which cannot be realized by the current technology. Therefore, without the prism 16, it is not possible to construct a multi-view stereoscopic image display device having tens of viewpoints. In this respect, according to this embodiment,
As described above, since the prism 16 can change the traveling direction of light and allow a plurality of real images of the light source to exist, even a low-speed LCD 15 can generate a multi-viewpoint image.

<Second Embodiment> FIG. 5 shows a stereoscopic image display apparatus according to a second embodiment of the present invention. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

The second embodiment is characterized in that a diffraction grating 56 is arranged in place of the prism 16 used in the first embodiment. This diffraction grating 56 is
It is composed of a plurality of gratings 56A to 56H corresponding to the pixels 15A to 15H of the LCD 15, and can change the traveling direction of the light emitted from the LCD 15. The function and effect are similar to those of the prism 16 used in the first embodiment.

That is, the light emitted from the first light source 12A and passing through the diffraction gratings 56A, 56C, 56E, and 56G can be changed in traveling direction by these diffraction gratings 56A, 56C, 56E, and 56G. The image is formed at the position of the real image 21A. The light observed at the position of the real image 21A is the pixels 15A, 15C, 15 of the LCD 15.
Since the intensity of light is modulated by E and 15G and the image input to these pixels is the image of the first camera 11A, at the position of the real image 21A, the first camera 11
The image of A is observed.

Further, the light emitted from the first light source 12A and passing through the diffraction gratings 56B, 56D, 56F and 56H is changed in traveling direction by these diffraction gratings 56B, 56D, 56F and 56H, and is located at the position of the real image 21B. Form an image. Real image 2
The light observed at the position of 1B is the pixel 15 of the LCD 15.
The intensity of light is modulated by B, 15D, 15F, 15H, and these pixels 15B, 15D, 15F, 15
Since the image input to H is the image of the camera 11B, the image of the camera 11B is observed at the position of the real image 21B.

In this way, the light from the first light source 12A is distributed by the diffraction grating 56, and the two real images 21A and 21B are distributed.
Can be generated, and images of two different cameras 11A and 11B can be observed at this real image position.

Instead of the first light source 12A, the second light source 12
Similarly, when B is emitted, the light of the second light source 12B is distributed by the diffraction grating 56, and the two real images 21C and 2C are generated.
1D can be generated. At this time, the image selector 1
Since 8 has selected the third camera 11C and the fourth camera 11D, two different cameras 11 are selected at the position of this real image.
Images of C and 11D can be observed.

Similarly, when the third light source 12C is emitting light, images of two different cameras 11E and 11F can be observed at the positions of the real images 21E and 21F.

Therefore, the real images 21 of these six light sources are
If the pitch between A and 21F is set to be about 65 mm or less between the human eyes, the left and right eyes of the human will see images taken from different directions, which is the same as the first embodiment. Similarly, it can be observed as a stereoscopic effect.

<< Third Embodiment >> FIG. 5 shows a third embodiment of the stereoscopic image display apparatus according to the present invention. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the third embodiment, instead of the prism 16 used in the first embodiment, four concave lenses 66 (first concave lens 66A, second concave lens 66B, third concave lens 66A, third concave lens 66B, and third concave lens 66B) are used.
It is characterized in that a concave lens 66C and a fourth concave lens 66D) are arranged. The first concave lens 66A is the prisms 16A and 16B, and the second concave lens 66B is the prism 16A.
C and 16D, the third concave lens 66C to the prism 16E,
It corresponds to 16F respectively.

Focusing on the first concave lens 66A, it is clear that if the outer shape of the concave lens 66A is approximated by a straight line, it will have the same shape as the prisms 16A and 16B used in the first embodiment. However, at this time, due to an error in approximation, the real images of the light sources 12A to 12C are not formed as clearly as in the first embodiment. For example, at the position of the real image 21C, not only the image of the third camera but also the images of the adjacent second camera 16B and the fourth camera 16D cause a crosstalk problem. Absent. Moreover, crosstalk can be improved by reducing the size of the light sources 12A to 12C.

According to each of the embodiments described above, it is not necessary to multiplex all multi-view information in the spatial direction as in the conventional example. Therefore, an ultra-high-definition spatial light modulator or a highly accurate lenticular lens is used. It is possible to provide a stereoscopic image display device without multi-eye glasses without needing. Also, with a lenticular lens, there is a physical limit to the resolution, and although a multi-view stereoscopic image display device with a certain number of viewpoints cannot be realized,
According to each of the above-described embodiments, it is possible to multiplex in the spatial direction up to the above-mentioned physical limit and further in the time direction, so that the number of viewpoints is larger than in the conventional example. An eye stereoscopic image display device can be realized. It is possible to multiplex all multi-view information on the time axis, but this requires an expensive spatial light modulator having an extremely fast response speed. In this regard, in each of the above-described embodiments, a multi-view stereoscopic image display device can be realized even if a spatial light modulator that is low in speed and relatively inexpensive is used.

<Other Embodiments> In each of the above embodiments, the images of the six-lens camera 11 are multiplexed on the time axis and in the horizontal direction of the space, but it is also possible to multiplex the space in the vertical direction. . In addition, in each of the above-described embodiments, 3 multiples on the time axis and 2 multiples in the horizontal direction of the space are set as a total of 3 × 2 = 6 multiplex. It is optional whether or not to multiplex.

Further, in the first embodiment, the prisms 16A and 16B may be replaced with the prisms 16C and 16D, and the prisms 16E and 16F may be replaced with each other. Further, in the second embodiment, the diffraction grating 56A and the diffraction grating 56B are
The diffraction grating 56C and the diffraction grating 56D may be replaced with the diffraction grating 56E and the diffraction grating 56F, respectively. Further, in the third embodiment, a convex lens may be used instead of the concave lens 66. In these cases, the spatial multiplexer 20
The parallax image taken from the position on the right is LC
It is displayed on the pixels 15A, 15C, 15E, and 15G on the D15, and at the same time, the other parallax image is the pixel 1 on the LCD 15.
The pixel interleave multiplexing method may be changed so that the images are displayed in 5B, 15D, 15F, and 15H.

[0045]

As described above, according to the first aspect of the invention, the optical element for changing the traveling direction of light is arranged on the front surface or the back surface of each pixel forming the spatial light modulator. Therefore, at the moment when one light source is turned on, there is only one real image due to the lens of the light source when this optical element is not present, but the real image due to the lens of the light source when this optical element is present is Since the direction can be changed by the optical element, a plurality of directions can exist. Thereby, an image having a plurality of viewpoints can be generated at one time, and an image of a larger number of viewpoints can be generated by time division by sequentially changing the position of the light source that emits light.

According to the invention of claim 2, a prism is used as the optical element for changing the traveling direction of light, and according to the invention of claim 3, a diffraction grating is used as the optical element for changing the traveling direction of light. did. Therefore, the same effect as that of the first aspect of the invention can be obtained, and the size of the generated real image of the light source can be made to be a constant multiple of the size of the light source.

According to the invention of claim 4, even if an optical element having an image forming function, that is, a lens such as a concave lens is used, if the size of the light source is small, there is practically no problem and stereoscopic vision is possible. To Then, by arranging the real images of the respective light sources in the vicinity of the observer without a gap, the observer can move the viewpoint freely and observe the stereoscopic image.

[Brief description of drawings]

FIG. 1 is a configuration explanatory view showing a first embodiment of a stereoscopic image display device according to the present invention.

FIG. 2 is an explanatory diagram showing an operation of the first embodiment shown in FIG.

FIG. 3 is an explanatory diagram showing the operation of the first embodiment shown in FIG.

FIG. 4 is an explanatory diagram showing an operation of the first embodiment shown in FIG.

FIG. 5 is a configuration explanatory view showing a second embodiment of a stereoscopic image display device according to the present invention.

FIG. 6 is a structural explanatory view showing a second embodiment of a stereoscopic image display device according to the present invention.

FIG. 7 is a configuration explanatory view showing a conventional example of a stereoscopic image display device.

[Explanation of symbols]

 11 6-eye camera 12A-12C Light source 13 Light emission control device 14 Fresnel lens 15 LCD (spatial light modulator) 15A-15H Pixel 16 Prism 18 Image selector 20 Spatial multiplexer 21A-21F Real image 56 Diffraction grating 66 Concave lens

Claims (4)

[Claims] 1. A plurality of light sources that sequentially flash, an image forming lens that forms an image of light from these light sources near the viewpoint of an observer, and a light source arranged opposite to the light source with the image forming lens interposed therebetween. Among the plurality of light sources, a spatial light modulation element that displays a parallax image according to the light source that is turned on, and a spatial light modulation element that is arranged close to the front surface or the back surface of each pixel that constitutes the spatial light modulation element. A stereoscopic image display device, comprising: an optical element that changes a traveling direction. 2. The stereoscopic image display device according to claim 1, wherein the optical element that changes the traveling direction of the light is a prism. 3. The stereoscopic image display device according to claim 1, wherein the optical element that changes the traveling direction of the light is a diffraction grating. 4. The stereoscopic image display device according to claim 1, wherein the optical element that changes the traveling direction of the light is a part of a single lens.