Optical: systems and elements – Holographic system or element – For producing or reconstructing images from multiple holograms
Reexamination Certificate
2001-04-17
2002-06-04
Schuberg, Darren (Department: 2872)
Optical: systems and elements
Holographic system or element
For producing or reconstructing images from multiple holograms
C359S022000, C359S035000
Reexamination Certificate
active
06400474
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to an image recording apparatus for creating a holographic stereogram recorded so that a photographed image or a computer-generated image can be observed three-dimensionally.
2. Description of Related Art
To create a holographic stereogram, for example, a subject is photographed from different observation points to generate many images as original pictures. These images are sequentially recorded as strip or dot element holograms on a single holographic recording medium.
For example,
FIG. 1
shows a holographic stereogram having parallax information in a cross direction only. A subject
90
is sequentially photographed crosswise from different observation points to generate a plurality of original pictures
91
a
to
91
e
. An image recording apparatus sequentially records these original pictures as element holograms in strips on a holographic recording medium
92
.
Image information is obtained by sequentially photographing from different observation points along a cross direction and is sequentially recorded crosswise as element holograms in strips. When an observer views this holographic stereogram with both eyes, right and left eyes accept slightly different 2-D images respectively. This causes the observer to feel parallax, reproducing a 3-D image.
FIG. 2
shows a configuration example of a printer for creating such a holographic stereogram (hereafter referred to as a holographic stereogram printer). FIG.
2
(A) is atop view of an entire optical system for a holographic stereogram printer
100
. FIG.
2
(B) is a side view of an object light portion of the optical system.
The holographic stereogram printer
100
captures many image data elements by crosswise photographing a real object from different observation points. Processed image data includes rendering images such as a plurality of CAD (Computer Aided Design) or CG (Computer Graphics) images created by sequentially providing parallaxes crosswise. Based on the processed image data, the holographic stereogram printer
100
drives an LCD (Liquid Crystal Display).
109
. Each image data is sequentially recorded as a hologram strip on a holographic recording medium
112
for creating a holographic stereogram.
Actually, in this holographic stereogram printer
100
, a separately provided system control section drives an LCD
108
based on one of a plurality of generated image data. The LCD
108
displays an image based on the image data. At this time, the system control section sends a control signal to a shutter
114
to open it. A laser beam L
10
generated from a laser light source
101
enters a spatial filter
104
via the shutter
114
, a half mirror
102
, and a mirror
103
, sequentially.
This laser beam L
11
is enlarged by the spatial filter
104
and a collimator lens
105
. The beam is transmitted through the LCD
108
and is converted to projection light corresponding to an image displayed on the LCD
108
. The beam then enters a cylindrical lens
107
via a condensing lens
106
. The beam is crosswise condensed by the cylindrical lens
107
and then enters a holographic recording medium
112
mounted on an electric stage
113
.
When the laser beam is applied to the holographic recording medium
112
, the laser beam L
12
reflected on the half mirror
102
is transmitted through the cylindrical lens
109
, the collimator lens
110
, and a mirror
111
in order. As reference light, the laser beam enters at a specified angle from the rear side of the holographic recording medium
112
. In this case, the optical path length of the reference light is specified so that it becomes approximately the same as the optical path length of a laser beam (hereafter referred to as an object light) which passes the half mirror
102
and then the mirror
103
and enters the holographic recording medium
112
.
The holographic stereogram printer
100
can let the object light (projection light) and the reference light interfere with each other on a recording surface of the holographic recording medium
112
. Consequently, an image displayed on the LCD
108
can be recorded as an interference pattern in strips on the holographic recording medium
112
.
When the image has been recorded in this holographic stereogram printer
100
thereafter, the system control section drives the shutter
114
to block the laser beam L
10
generated from the laser light source
101
. The LCD
108
is also stopped. Under control of the system control section, the electric stage
113
is driven to feed the holographic recording medium
112
for the width of one hologram strip in the direction of an arrow b.
Under control of the system control section thereafter, the LCD
108
is driven to display an image based on the succeeding image data: Then, the system control section opens the shutter
114
to record the image displayed on the LCD
108
onto the holographic recording medium
112
. After that, the operation is repeated successively.
Hence, the holographic stereogram printer
100
can successively record images in strips onto the holographic recording medium
112
based on image data in a supplied parallax image sequence. This can provide a desired holographic stereogram.
The above-mentioned holographic stereogram printer needs a means for holding and transferring a holographic recording medium. Such means must completely fix the holographic recording medium during exposure, cause no vibration as small as a wavelength, fast transfer the medium and leave no vibration after a stop. However, it takes approximately 2 seconds for the electric stage
113
of the holographic stereogram printer
100
until a vibration attenuates after the transfer. When this electric stage
103
is used to transfer the medium each time a hologram strip is formed, it will take a very long time until one holographic stereogram is completed.
An examination was conducted concerning the holding and transfer means capable of suppressing the vibration of the holographic recording medium. Instead of the above-mentioned electric stage
113
, a method has been devised to load a long holographic recording medium between two parallel rollers, use a torsion coil spring or the like to provide a given tension for support, and irradiate object light by pressing optical parts against a bridge between the two parallel rollers. This configuration can decrease the time for attenuating the vibration after the transfer to a quarter or less. However, there is a problem of complicating the mechanism for allowing the torsion coil spring to stably generate a given force.
As with a conventional printer or printing apparatus, it is possible to generate easily a given torque without using a torsion coil spring by always rotating a slip material reversely and transmitting a motor drive to one of the parallel rollers. Since the motor rotates even during exposure of the hologram, this rotation generates an unnecessary vibration, deteriorating the image quality.
Applying an excess tension to such a film material in the longer direction easily ripples the film surface and prevents the film from being parallelized. This caused an image to be distorted or to lose uniformity.
When a holding method is used to cause a large stress difference between the longer and shorter directions, double refraction occurs on a base filth or a cover film. This also could cause image deterioration. When the medium is pressed against a glass, a dust particle enters to lift the exposed portion. This also ripples the film and gives a disadvantageous effect on the image.
BRIEF SUMMARY OF THE INVENTION
It is an object of the present invention to provide an image recording apparatus which can simply and reliably prevent a holographic recording medium from vibrating. It also is an object of the present invention to provide a holographic recording medium cartridge which can protect the holographic recording medium against external dust and the like.
For solving the above problems, an image recording apparatus according to the present invention irradiates ob
Kananen, Esq. Ronald P.
Radar Fishman & Grauer PLLC
Schuberg Darren
Sony Corporation
LandOfFree
Image recording apparatus and holographic recording medium... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Image recording apparatus and holographic recording medium..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Image recording apparatus and holographic recording medium... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2965221