Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Patent
1994-04-13
1995-12-19
Hjerpe, Richard
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
345 98, 345211, G09G 336
Patent
active
054772346
ABSTRACT:
A drive circuit is disclosed for a liquid crystal display apparatus of the active matrix type having a large number of gray levels that can be displayed. The drive circuit comprises a plurality of sections each including a sample-and-hold circuit 22. The sample-and-hold circuit 22 has a plurality of switches Sw 1 through Sw 4. To these switches are separately supplied different ramp signals Vr 1 through Vr 4 from a ramp generator circuit 24 shared by all the sections. These ramp signals have waveforms which respectively assume a plurality of different voltage levels and are shifted from each other by a predetermined voltage level. The decoder 21 selects one of the switches Sw 1 through Sw 4 and a specific one of the voltage levels in the ramp signal applied to that selected switch depending on the gray scale data in the latch 20. The output of the sample-and-hold circuit is transmitted to the data line 7a via a buffer 23.
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Suzuki Hiroshi
Suzuki Midori
Drumheller Ronald L.
Hjerpe Richard
International Business Machines - Corporation
Saras Steven
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