Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Patent
1997-11-14
2000-03-21
Sikes, William L.
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
349156, 349 5, G02F 11339, G02F 11335
Patent
active
06040888&
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to a liquid crystal display device and a method for the manufacture thereof, and more specifically, to a projection-type liquid crystal display device using liquid crystal light valves, and a method for the manufacture thereof.
2. Description of the Prior Art
In recent years, a projection type liquid crystal display device has assumed a new prominence as a potential ultra-high definition display device which replaces CRTs. The projection type liquid crystal display device has already been used in HDTV or OEP displays.
The projection optical system of the projection type liquid crystal display device consists of a light source, light valves, a screen, optical filters, and projection lenses. Liquid crystal panels are used as the light valves. Light valves are classified into a transmission type liquid crystal light valve, which transmits light from the light source and projects images on the screen, and a reflection type liquid crystal light valve, which reflects light from the light source and projects images on the screen. Since liquid crystal light valves generally reflect/transmit the lights of three primary colors, red (R). green (G). and blue (B), three light valves are used in a projection type liquid crystal display device.
A liquid crystal display device of the active matrix type consists generally of an array substrate on which there are interconnected switching elements and display electrodes and a counter substrate on which there are a counter electrode facing to the array substrate at a predetermined distance (cell gap) from the array substrate. Liquid crystal material is enclosed between the array substrate and the counter substrate.
In order to achieve desired electro-optical properties of the liquid crystal, the predetermined cell gap must be maintained evenly throughout the entire display surface of the panel. To accomplish this, some display devices use a large number of glass or plastic beads having a diameter of several microns dispersed on the panel as spacers to make the cell gap even. However, this method with using spacers has problems of the uniformity of beads diameters and difficulty in the even dispersion of spacer beads on the panel, as well as the loss of light due to spacers on pixels.
Instead of the above spacer bead dispersion method, a method has been proposed of forming columns consisting of an insulation film and the like in the cell gap as spacers. In this method, columns of a silicon oxide film are formed in the cell gap as spacers (pillar-shape spacers). by using photolithography commonly used in the manufacturing process of semiconductor devices. This method is advantageous compared with the conventional method of using spacer beads in that a cell gap is formed with a high accuracy.
For example, in some reflection type liquid crystal light valves where a silicon substrate is used as the array substrate, an MOS transistor as the switching element and an aluminum (Al) reflecting film connected to said MOS transistor are provided on the array substrate for each element, and a plurality of pillar-shape spacers are formed in the shaded on black matrix region between reflecting films.
In a projection type liquid crystal display device which displays high-definition images on a large screen, the improvement of display brightness is important.
In order to improve display brightness an increase in the numerical aperture of subpixels is considered. In a reflection type liquid crystal light valve, pillar-shape spacers are formed between two reflecting films, and the ends of the spacers override the reflecting films to decrease the reflection area of the reflecting films, causing the numerical aperture of subpixels to lower.
Also in the cell gap forming system using such pillar-shape spacers, even if the overriding of spacers on the reflecting films as described above could be prevented not to affect the numerical aperture, other factors lowering display qualities still remain.
First, where there are pil
REFERENCES:
patent: 4775225 (1988-10-01), Tsuboyama et al.
patent: 4999619 (1991-03-01), Te Velde
patent: 5379139 (1995-01-01), Sato et al.
patent: 5499128 (1996-03-01), Hasegawa et al.
patent: 5552913 (1996-09-01), Shimizu et al.
patent: 5680189 (1997-10-01), Shimizu et al.
patent: 5739882 (1998-04-01), Shimizu et al.
patent: 5739890 (1998-04-01), Uda et al.
patent: 5777713 (1998-07-01), Kimura
patent: 5828434 (1998-10-01), Koden et al.
Enami Kunio
Masami Shinohara
Uda Mitsuru
Chowdhury Tarifur R.
International Business Machines - Corporation
Sbrollini J. P.
Sikes William L.
LandOfFree
Positioning of posts in liquid crystal valves for a projection d does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Positioning of posts in liquid crystal valves for a projection d, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Positioning of posts in liquid crystal valves for a projection d will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-734712