Radiation imagery chemistry: process – composition – or product th – Holographic process – composition – or product – Composition or product or process of making the same
Patent
1997-02-28
1998-12-22
Berman, Susan W.
Radiation imagery chemistry: process, composition, or product th
Holographic process, composition, or product
Composition or product or process of making the same
430 1, 430 6, 430 7, 430 20, 522 96, 522 97, 522182, 359599, 359504, G03H 104, C09K 1900, G02B 502
Patent
active
058517006
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a filter for a liquid crystal display device, which will widen an angle of view and suppress the decrease in picture quality caused by opaque parts of the device, when the filter is fitted to the liquid crystal display device.
DESCRIPTION OF CONVENTIONAL ART
In these times, a liquid crystal display device is expected to be a display device which can compete with a cathode ray tube (CRT), because of its characteristics such as its thinness, light weight and high picture quality. The modes of the liquid crystal display device which, have been developed include twisted nematic (TN) a type, a super twisted nematic (STN) type, a ferroelectric type and a polymer dispersion type. Liquid crystal display devices with multicolor and high definition are commercially sold.
With the demand for a large area display and development of a high-vision technique, an enlarging projection type display device is becoming desired. In addition, with the increase of processing speed in computers, a virtual reality display device has been developed which displays an image as if it were actually present, using a liquid crystal display device as a display device which is worn on a head like a goggles.
Most of the liquid crystal display devices mainly use the TN or STN addressing mode. Such an addressing mode has a drawback in that the angle of view in which the image has satisfactory quality is narrow since, when a displayed image is seen from an upper or lower angle and/or a right or left side angle, brightness and contrast of the image are considerably deteriorated. This characteristic of the angle of view has been studied for a long time to improve it.
As one of the methods for the improvement of the above drawback, a method for correcting a pretilt angle of the liquid crystal molecule using an orientation separating technique has been studied. However, since this method makes the production step complicated, a large increase of production cost is unavoidable.
As a simple method, there is known a method for diffusing light in a wide angle range by providing a diffusing sheet on the liquid crystal display panel. Since the transmission of the diffusing sheet is usually 80% or less, the brightness of the liquid crystal display face plane is decreased. The effect of enlarging the angle of view becomes larger as the angular distribution of light to be diffused by the diffusing sheet becomes wider. However, a currently used diffusing sheet has a narrow light diffusing angle, and a sheet having a wide diffusing angle is sought.
A liquid crystal display device based on another addressing mode is under development, and does not exhibit commercially sufficient performance.
In the liquid crystal display device, opaque parts such as a bus electrode or a thin film electrode (TFT) are provided around pixels. In the case of a display device which enlarges the image of the liquid crystal display device such as the liquid crystal projector or the virtual reality display device, since the opaque parts form shadows on a displayed picture which is enlarged and projected, the image quality is considerably deteriorated.
To cope with this problem, Japanese Patent KOKAI Publication Nos. 232460/1993 and 273540/1993 propose the provision of a phase lattice on a substrate of a transmission type liquid crystal display device, which is on the light emitting side. This proposal suppresses the decrease of image quality by bending a light beam which passes through a pixel of the liquid crystal display device by a light diffraction effect of the phase lattice to shift the light beam to the shadow formed by the opaque part. As the phase lattice, there are exemplified a shape modulation type phase lattice which can be produced by a photolithography method and a refractive index modulation type phase lattice which is prepared by distributing a monomer having a different refractive index in the resin and polymerizing. Since the phase lattice easily generates Moire fringes due to its regular structure, the ac
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Electronic Technology (Denshi Gijutsu), 1992-6, pp. 49-52 "Polymer Dispersed LCD Begins . . . " (partial translation).
Nikkei Materials & Technology, 93/12 (No. 136), pp. 43-45 (partial translation).
Multi Domain Pixel Structures and Their Improvement for Angular Dependency, Ken Sumiyoshi, Dec. 15, 1993 (translation).
Honda Masaru
Hozumi Shigeo
Kitayama Shinichiro
Berman Susan W.
Sumitomo Chemical Company Limited
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