Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Reexamination Certificate
1997-10-31
2003-04-22
Hjerpe, Richard (Department: 2674)
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
C345S099000
Reexamination Certificate
active
06552704
ABSTRACT:
BACKGROUND OF THE INVENTION
Flat-panel displays are being developed which utilize liquid crystals or electroluminescent materials to produce high quality images. These displays are expected to supplant cathode ray tube (CRT) technology and provide a more highly defined television picture or computer monitor image. The most promising route to large scale high quality liquid crystal displays (LCDs), for example, is the active-matrix approach in which thin-film transistors (TFTs) are co-located with LCD pixels. The primary advantage of the active matrix approach using TFTs is the elimination of cross-talk between pixels, and the excellent grey scale that can be attained with TFT-compatible LCDs.
Color liquid crystal flat panel displays can be made in several different ways including with color filters or sequentially flashing lights. Both style displays are found in transmissive or reflective models.
Transmissive color filter liquid crystal flat panel displays generally include five different layers: a white light source, a first polarizing filter that is mounted on one side of a circuit panel on which the TFTs are arrayed to form pixels, a filter plate containing at least three primary colors arranged into pixels, and finally a second polarizing filter. A volume between the circuit panel and the filter plate is filled with a liquid crystal material. This material will allow transmission of light in the material when an electric field is applied across the material between the circuit panel and a ground affixed to the filter plate. Thus, when a particular pixel of the display is turned on by the TFTs, the liquid crystal material rotates polarized light being transmitted through the material so that the light will pass through the second polarizing filter.
In sequential color displays, the display panel is triple scanned, once for each primary color. For example, to produce color frames at 20 Hz, the active matrix must be driven at a frequency of 60 Hz. In order to reduce flicker, it is desirable to drive the active matrix at 180 Hz to produce a 60 Hz color image. At over 60 Hz, visible flicker is reduced.
Owing to the limitations of amorphous silicon, other alternative materials include polycrystalline silicon, or laser recrystallized silicon. These materials are limited as they use silicon that is already on glass, which generally restricts further circuit processing to low temperatures.
Integrated circuits for displays, such as, the above referred color sequential display, are becoming more and more complex. For example, the color sequential display is designed for displaying High Definition Television (HDTV) formats requiring a 1280-by-1024 pixel array with a pixel pitch, or the distance between lines connecting adjacent columns or rows of pixel electrodes, being in the range of 15-55 microns, and fabricated on a single five-inch wafer.
SUMMARY OF THE INVENTION
In accordance with the invention, the cost and complexity of high resolution displays are significantly reduced by fabricating multiple integrated displays of reduced size on a single wafer and then dicing the wafer to produce a plurality of display devices.
The displays are then assembled with appropriate magnifying optics to form a portable display system of low cost and reduced size. Included in the optics is a magnification system which compensates for the small image size by magnifying and projecting the image at an appropriate distance for viewing.
In preferred embodiments, an active matrix color sequential liquid crystal display has an active matrix circuit, a counterelectrode, panel and an interposed layer of liquid crystal. The active matrix circuit has an array of transistor circuits formed in a first plane. Each transistor circuit is connected to a pixel electrode in an array of pixel electrodes having an area of 200 mm
2
or less and preferably under 100 mm
2
. The counterelectrode panel extends in a second plane that is parallel to the first plane, such that the counterelectrode panel receives an applied voltage. The liquid crystal layer is interposed in a cavity between the two planes. The cavity has a depth along an axis perpendicular to the first and second planes of less than 3 microns.
In a preferred embodiment, an oxide layer extends between the pixel electrode array and a layer of liquid crystal material. The oxide has a first thickness in a peripheral region around the array of pixel electrodes and a thinner second thickness in a pixel electrode region extending over the array of pixel electrodes. The thick peripheral region (about 0.5 microns in a preferred embodiment) serves to better isolate the driver electrodes integrated into the display circuit. The thinner oxide region (about 0.3 microns) serves to reduce the voltage drop across the oxide during display operations. This serves to increase the applied voltage on the liquid crystal without the need to draw more power from the power source such as a battery.
In a preferred embodiment, the liquid crystal is a superfluoriated material. This material has the desired combination of characteristics that improves color sequential operation. A preferred method of controlling the liquid crystal in the display includes switching the applied voltage to the counterelectrode panel after every subframe.
REFERENCES:
patent: 4010322 (1977-03-01), Nathanson
patent: 4159417 (1979-06-01), Rubincam
patent: 4258387 (1981-03-01), Lemelson et al.
patent: 4336524 (1982-06-01), Levine
patent: 4532506 (1985-07-01), Kitazima et al.
patent: 4573766 (1986-03-01), Bournay, Jr., et al.
patent: 4630895 (1986-12-01), Abdala, Jr. et al.
patent: 4636866 (1987-01-01), Hattori
patent: 4695129 (1987-09-01), Faessen et al.
patent: 4704740 (1987-11-01), McKee et al.
patent: 4714980 (1987-12-01), Hara
patent: 4814876 (1989-03-01), Horio et al.
patent: 4837817 (1989-06-01), Maemori
patent: 4856045 (1989-08-01), Hoshina
patent: 4856088 (1989-08-01), Oliwa et al.
patent: 4873576 (1989-10-01), Hattori et al.
patent: 4916441 (1990-04-01), Gombrich
patent: 4917469 (1990-04-01), Ross
patent: 4928300 (1990-05-01), Ogawa et al.
patent: 4934773 (1990-06-01), Becker
patent: 4958915 (1990-09-01), Okada et al.
patent: 4959642 (1990-09-01), Sharples
patent: 4977456 (1990-12-01), Furuya
patent: 4985697 (1991-01-01), Boulton
patent: 5003300 (1991-03-01), Wells
patent: 5008658 (1991-04-01), Russay et al.
patent: 5008788 (1991-04-01), Palinkas
patent: 5012274 (1991-04-01), Dolgoff
patent: 5023931 (1991-06-01), Streck et al.
patent: 5042918 (1991-08-01), Suzuki
patent: 5048077 (1991-09-01), Wells et al.
patent: 5077784 (1991-12-01), Fujita et al.
patent: 5079627 (1992-01-01), Filo
patent: 5087113 (1992-02-01), Sakono et al.
patent: 5106179 (1992-04-01), Kamaya et al.
patent: 5111498 (1992-05-01), Guichard et al.
patent: 5122880 (1992-06-01), Nagano
patent: 5132825 (1992-07-01), Miyadera
patent: 5138312 (1992-08-01), Tsukamoto et al.
patent: 5162828 (1992-11-01), Furness et al.
patent: 5164833 (1992-11-01), Aoki
patent: 5164980 (1992-11-01), Bush et al.
patent: 5177405 (1993-01-01), Kusuda et al.
patent: 5185712 (1993-02-01), Sato et al.
patent: 5189632 (1993-02-01), Paajanen et al.
patent: 5199104 (1993-03-01), Hirayama
patent: 5206749 (1993-04-01), Zavracky et al.
patent: 5220366 (1993-06-01), King
patent: 5224198 (1993-06-01), Jachimowicz et al.
patent: 5239665 (1993-08-01), Tsuchiya
patent: 5256562 (1993-10-01), Vu et al.
patent: 5258325 (1993-11-01), Spitzer et al.
patent: 5260625 (1993-11-01), Holden et al.
patent: 5280372 (1994-01-01), Horiuchi
patent: 5281957 (1994-01-01), Schoolman
patent: 5300788 (1994-04-01), Fan et al.
patent: 5300976 (1994-04-01), Lim et al.
patent: 5305244 (1994-04-01), Newman et al.
patent: 5311206 (1994-05-01), Nelson
patent: 5317236 (1994-05-01), Zavracky et al.
patent: 5321416 (1994-06-01), Bassett et al.
patent: 5322989 (1994-06-01), Long et al.
patent: 5325429 (1994-06-01), Kurgan
patent: 5331333 (1994-07-01), Tagawa et al.
patent: 5335276 (1994-08-01), Thompson et al.
patent: 5337068 (1994-08-01), Stewart et al.
patent: 5347378 (1994-09-01), Handschy et al.
paten
Chern Wen-Foo
Fan John C. C.
Ong Hiap L.
Richard Alan
Tsaur Bor-Yeu
Hamilton Brook Smith & Reynolds P.C.
Hjerpe Richard
Kopin Corporation
Laneau Ronald
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