Optical: systems and elements – Stereoscopic – Having record with lenticular surface
Reexamination Certificate
1999-03-24
2004-03-23
Chang, Audrey (Department: 2872)
Optical: systems and elements
Stereoscopic
Having record with lenticular surface
C359S462000, C359S464000, C353S007000
Reexamination Certificate
active
06710920
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a stereoscopic display by which a stereoscopic image can be observed without using special eye-glasses.
2. Description of the Prior Art
A stereoscopic display of double-lenticular type which uses two liquid crystal projectors and a double lenticular screen as a screen to realize stereoscopic image display without using special eye-glasses has been proposed. In the stereoscopic display of this type as shown in
FIG. 15
, one liquid crystal projector
100
a
displays an image for a left eye, and another liquid crystal projector
100
b
displays an image for a right eye. The images from the projectors are projected on a double lenticular screen
200
which is arranged in front of the projectors. The double lenticular screen
200
is constructed so that a diffusing plate
200
b
, which forms an image, is sandwiched by lenticular screens
200
a
and
200
c
. Images for left and right eyes become vertical stripe-shaped images
200
b
L and
200
b
R respectively by passing through the lenticular screen
200
a
, which is positioned on a light incident side (on the side of liquid crystal projectors
100
a
and
100
b
). And the vertical stripe-shaped images
200
b
L and
200
b
R are formed on the diffusing plate
200
b
. After that, these images are separated into the stripe-shaped image for a right eye and a left eye by passing through the lenticular screen
200
c
which is positioned on a light emitting side of the diffusing plate
200
b
(on the side of a viewer), then the image for a right eye is guided to a right eye (
3
R) of a viewer
300
and the image for a left eye is guided to a left eye (
3
L) of the viewer
300
. The viewer, who observes these vertical stripe-shaped images for left and right eyes by the respective eyes, can observe a stereoscopic image without using special eye-glasses, due to the binocular parallax effect.
The stereoscopic display of this type provides a region in which an image for a right eye is visible and a region in which an image for a left eye is visible alternately at the optimum viewing distance from a screen
200
(“D” in the figure) as shown in FIG.
16
. The “R” region indicated by an arrow is a region where an image for a right eye can be observed and the “L” region is a region where an image for a left eye where an image for a left eye can be observed. Accordingly, a viewer can observe a stereoscopic image when the right eye
3
R of the viewer is in the “R” region and the left eye
3
L is in the “L” region (the viewer is at the “A” position in the figure). When the right eye of the viewer is in the “L” region and the left eye is in the “R” region (the viewer is at the “B” position in the figure), a viewer observes a pseudo-stereoscopic image and can not observe a stereoscopic image.
The conventional methods which can prevent a pseudo-stereoscopic image caused by a shift of the viewer's head include the following one. As illustrated in
FIGS. 17 and 18
, a sensor
210
which detects a head position of a viewer
300
detects a head position of the viewer
300
. When the sensor determines the viewer is at a pseudo-stereoscopic viewing position, images from the two projectors
100
a
and
100
b
(not shown in
FIGS. 17 and 18
) are replaced from one another. In such a construction, when the viewer
300
moves from the stereoscopic viewing position of image to the pseudo-stereoscopic viewing position (FIG.
17
), the images are replaced from one another as shown in FIG.
18
. As a result, an image viewing region “R” of diamond shape can be placed at a position corresponding to the viewer's right eye, and an image viewing region “L” of diamond shape can be placed at a position corresponding to the viewer's left eye.
SUMMARY OF THE INVENTION
The conventional method as above mentioned requires, however, a means to switch images for left and right eyes. When a large sized display is used, the number of viewer is sometimes plural. In this case, one of the viewer moves and thus images for a left eye and for a right eye are switched. This causes a problem that the other viewers who are in stereoscopic position can not observe stereoscopic images.
The present invention is made in consideration of the above circumstances and it is an object of the invention to provide a stereoscopic display without using special eye-glasses which enable each viewer to observe a stereoscopic image without using a means to switch images for left and right eyes even when images are observed by a plurality of viewers.
To solve the problem, a stereoscopic display without using eye-glasses of the present invention comprises a first projector which projects an image for a left eye, a second projector which projects an image for a right eye, an image forming means which forms images for left and right eyes projected from the projectors onto a diffusing plate, a shutter means which includes a plurality of shutter regions disposed laterally which can switch between light transmission and light shading, and forms a narrow-width image light reaching region, of which width is less than that of the image forming region, in each image forming region on the diffusing plate, a light guide means which guides an image in a narrow-width image light reaching region for a left eye in the image forming region for a left eye to the left eye of the viewer and guides an image in a narrow-width image light reaching region for a right eye in the image forming region for a right eye to the right eye of the viewer, a shutter control means which controls light transmission and light shading of the shutter region on the basis of output results from a sensor which detects a viewer's position.
In the above construction, each image is fractionized in the image forming region for a left eye and the image forming region for a right eye on the diffusing plate due to the placement of shutter means . That is, an image light region of narrow-width (a light emitting point) is formed in the narrow-width image light reaching region. The images in each narrow-width image light reaching region which are fractionized move respectively in response to the viewer's position when being controlled light transmission and light shading of each shutter region by the shutter control means, resulting in realization of head tracking against the viewer. The more images in the narrow-width image light reaching region formed in each image forming region exist, the more viewers can observe a stereoscopic image.
A stereoscopic display without using eye-glasses of this invention comprises a left-eye system, a right-eye system, and a half mirror which guides an image for a left eye from the left-eye system and an image for a right eye from the right-eye system by transmitting an image light from either of the systems and reflecting an image light from the other system, further, the left-eye system is composed by a first projector which projects an image for a left eye, an image forming means which forms an image for the left eye projected from the projector onto the diffusing plate in predetermined width, a shutter means which includes a plurality of shutter regions disposed laterally which can switch between light transmission and light shading, and forms a narrow-width image light reaching region, of which width is less than that of the image forming region, in each image forming region on the diffusing plate, a light guide means which guides an image in a narrow-width image light reaching region in the image forming region to a left eye of a viewer, a shutter control means which controls light transmission and light shading of the shutter region on the basis of output results from a sensor which detects a viewer's position, and the right-eye system is composed by a second projector which projects an image for a right eye, an image forming means which forms an image for the right eye projected from the projector onto the diffusing plate, a shutter means which includes a plurality of shutter regions disposed laterally which ca
Hamagishi Goro
Inoue Masutaka
Kanayama Hideyuki
Mashitani Ken
Arent Fox Kintner & Plotkin & Kahn, PLLC
Chang Audrey
Sanyo Electric Co., LTD
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