Optical: systems and elements – Optical modulator – Light wave temporal modulation
Reexamination Certificate
1999-10-29
2001-02-27
Ben, Loha (Department: 2873)
Optical: systems and elements
Optical modulator
Light wave temporal modulation
C359S291000, C359S619000, C359S254000, C359S230000, C359S245000, C362S035000, C349S064000, C385S146000
Reexamination Certificate
active
06195196
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an array-type light modulator incorporating flexible thin films to change transmittance of light, an array-type exposing device for use in a UV sensitive material, a visible light sensitive material or an IR sensitive material and a flat-type display unit incorporating the array-type light modulator to cause a phosphor to emit light to perform display.
Hitherto, digital exposing methods for use in a variety of image forming processes include a method using a laser beams, a method using a UV light source and an LCD shutter and a method using a UV light source and an electrooptic crystal shutter.
The method using a laser beam, for example, raster is a scan for relatively moving an image forming member and a laser beam so that successive exposing operations are performed. The foregoing method is able to form a fine image by an image generating function thereof.
The method using a UV light source and an LCD shutter uses change in the optical characteristic occurring when changes in the arrangement of molecules by dint of an electric field of the LCD shutter so as to selectively shield UV rays so that exposure is controlled.
The method using a UV light source and an electrooptic crystal shutter, such as Pockels cell, uses a linear electrooptic effect of electrooptic crystal, the refractive index of which is changed in proportion to the first power of an applied electric field. The Pockels cell is obtained by cutting a parallel and flat plate of electrooptic crystal vertically to an optical axis thereof. An electric field is applied in a direction of the optical axis. Then, birefringence which occurs when a UV ray is allowed to pass in the foregoing direction is used to control the exposure.
A variety of thin and flat display units have been disclosed which are represented by, for example, a liquid crystal display unit, a plasma display unit and a field emission display (FED).
The liquid crystal display unit has a structure that oriented liquid crystal is enclosed and sealed between a pair of substrates each having a conductive transparent film. Moreover, the foregoing structure is held between perpendicular deflection plates. The liquid crystal display unit performs display such that voltage is applied to the conductive transparent film so that liquid crystal is oriented perpendicular to the substrates so as to change transmittance of light emitted from a backlight. To perform full color display or to display a dynamic image, an active matrix liquid crystal panel incorporating TFT (a thin film transistor) is employed.
The plasma display unit has a structure that a multiplicity of electrodes corresponding to an anode and a cathode and arranged regularly are disposed between two glass plates between which a rare gas, such as neon, has been enclosed. Moreover, intersections of opposing electrodes serve as unit pixels. The plasma display unit performs display in accordance with image information to selectively apply voltage to opposing electrodes with which an intersection is specified. Thus, the intersection is caused to perform discharge and emit light so as to excite phosphor with a generated UV ray.
The FED has a structure formed into a flat display tube which covers a pair of panels disposed apart from each other for a short distance to be opposite to each other. A fluorescent film is formed on the inner surface of the displaying panel. Electric field emission cathodes for corresponding unit light emitting regions are disposed on the rear panel. The electric field emission cathode incorporates pointed electric field emission type micro-cathode called an emitter tip having a small size. Display performed by the FED is performed by causing the emitter tip to emit electrons which are then accelerated so that the phosphor is irradiated. As a result, the phosphor is excited.
However, the above-mentioned light modulator, the exposing device and the flat-type display unit have a variety of the following problems.
That is, the structure using a laser beam cannot reduce the size of the apparatus. What is worse, the cost of the apparatus is raised excessively. Since the laser beam is used to perform scanning so as to perform the exposure, exposure of the overall image forming member cannot be performed. Therefore, a multichannel structure cannot easily be constituted and high speed exposure cannot easily be performed.
The structure using the UV light source and the LCD shutter involves transmission of the UV ray to pass through a plurality of transmissive elements which constitute the LCD shutter. Therefore, the efficiency in using light deteriorates. Another problem arises in that the durability of the LCD shutter against the UV ray is unsatisfactory.
The structure using the UV light source and the electrooptic crystal shutter must be applied with a very high operating voltage. What is worse, a two-dimensional array structure cannot easily be constituted because the electrooptic crystal shutter is manufactured by cutting crystal, such as ADP (NH
4
H
2
PO
4
) or KDP (KH
2
PO
4
).
SUMMARY OF THE INVENTION
In view of the foregoing, a first object of the present invention is to provide an array-type exposing device which does not use a laser beam which raises the cost of the apparatus, which is able to perform exposure at high speed, with which a satisfactory freedom can be permitted when a light modulating mechanism is designed, which permits bright exposure and which is able to lower the operation voltage.
A second object is to provide a flat display unit which does not require high vacuum, which is able to realize a large area structure with a low cost, which exhibits an excellent efficiency of using light and which does not require high voltage when the unit is operated.
A third object of the present invention is to provide an operating method for the above which permits multiplicity gradation levels to be controlled in each pixel unit even if each of the light modulating portions is in a binary mode.
A fourth aspect of the present invention is to provide an operating method for the above with which a stable operation can be performed even if the above device has a hysteresis characteristic in the light modulating.
In order to achieve the above object, there is provided an array-type exposing device for exposing an image forming body incorporated in an image forming apparatus, comprising: a flat light source for emitting a UV ray; and a light modulator unit disposed above the flat light source so as to be associated with at least one unit area derived by dividing each of pixels on the image, the light modulator unit modulating the UV ray by electro-mechanical operation to expose the image forming body.
The foregoing exposing device has the light modulator section which are electro-mechanically operated. Thus, for example, a Fabry-Perot effect is used to control the intensities of light beams emitted from the light modulator section so that modulation of light is permitted.
The light modulator unit includes: a first electrode disposed above the flat light source; a second electrode disposed opposite to the first electrode such that at least a gap is interposed; a flexible thin film, which is transparent with respect to UV rays, interposed between the first and second electrodes and to be elastically deflected by Coulomb force generated when an electric field is applied therebetween.
As a result, an exposing device having a laminated structure can be constituted. Since a light beam emitted from the light guide plate is allowed to pass through only the pair of the transparent electrodes interposing a gap, the efficiency of using light can be improved.
It may be constituted that: the first electrode includes a plurality of band-like electrodes arranged in parallel with each other, the second electrode includes a plurality of band-like electrodes arranged in parallel with each other so as to be perpendicular to the first electrode; and at least one of intersections of the first and second electrodes is associated with one pixel of th
Kimura Koichi
Sawano Mitsuru
Ben Loha
Fuji Photo Film Co. , Ltd.
Sughrue Mion Zinn Macpeak & Seas, PLLC
LandOfFree
Array-type exposing device and flat type display... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Array-type exposing device and flat type display..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Array-type exposing device and flat type display... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2602027