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United States Patent  [ii] Patent Number: 5,497,172
Doherty et al.  Date of Patent: Mar. 5, 1996
 PULSE WIDTH MODULATION FOR
SPATIAL LIGHT MODULATOR WITH SPLIT
 Inventors: Donald B. Doherty, Richardson;
Robert J. Gove, Piano; Mark L.
Burton, Dallas; Rodney D. Miller,
Frisco, all of Tex.
 Assignee: Texas Instruments Incorporated,
 Appl. No.: 259,402
 Filed: Jun. 13, 1994
 Int. CI.6 G09G 3/34
 U.S. CI 345/85; 345/108
 Field of Search 345/89, 108, 85,
 References Cited
U.S. PATENT DOCUMENTS 5,079,544 1/1992 Demond et al. .
5,185,602 2/1993 Bassetti, Jr. et al 345/89
5,245,328 9/1993 Garrett 345/89
5,280,277 1/1994 Hornbeck 345/108
5,313,224 5/1994 Singhal et al 345/89
Primary Examiner—Ulysses Weldon Attorney, Agent, or Firm—Julie L. Reed; Richard L. Donaldson; William E. Hiller
A method of implementing pulse-width modulated image display systems (10, 20) with a spatial light modulator (SLM) (15) configured for split-reset addressing. Display frame periods are divided into time slices. Each frame of data is divided into bit-planes, each bit-plane having one bit of data for each pixel element and representing a bit weight of the intensity value to be displayed by that pixel element. Each bit-plane has a display time corresponding to a number of time slices, with bit-planes of higher bit weights being displayed for more time slices. The bit-planes are further formatted into reset groups, each reset group corresponding to a reset group of the SLM (15). The display times for reset groups of more significant bits are segmented so that the data can be displayed in segments rather than for a continuous time. During loading, segments of corresponding bit-planes are temporally aligned from one reset group to the next. The display times for less significant bits are not segmented but are temporally aligned to the extent possible without loading conflicts.
13 Claims, 3 Drawing Sheets