Display device drive circuit
First Claim
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1. A system for applying various voltage levels of a ramp voltage to the individual columns of pixels in a display device having a matrix of pixels arranged vertically in columns and horizontally in rows comprising:
- a plurality of voltage responsive signal transfer means individually actuating said columns of pixels, said signal transfer means simultaneously receiving said ramp voltage whereby pixel columns actuated by conductive signal transfer means are charged to voltage levels proportional to the level of said ramp voltage;
means for providing an analog information signal having brightness levels for controlling the brightness of said pixels;
means for receiving said analog information signal and providing digital brightness signals individually indicative of said brightness levels;
digital storage means for receiving and storing said digital brightness signals, said digital storage means including a plurality of digital storage sets, each of said digital storage sets having a plurality of serially loaded digital storage segments, each of said digital storage segments storing said grey scale codes for one of said columns of pixels to individually provide said brightness signals to said columns;
a plurality of counter means individually responsive to said digital storage segments for receiving said digital brightness signals as brightness counts for each of said columns, whereby said counter means are set to counts equal to said brightness levels and are set to count to zero, said counter means individually actuating said voltage reponsive signal transfer means whereby each of said signal transfer means is conductive when the associated counter is counting and nonconductive when the associated counter reaches zero whereby the pixels of individual columns are charged to various voltage levels of said ramp voltage in accordance with said brightness levels.
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Abstract
A drive circuit for a liquid crystal display includes a counter for each column of the display. The counters are set with brightness counts to establish the grey scales for the pixels. The counters turn transfer gates on when a count is present and off when the count is zero. An analog generator biases the columns through the transfer gates so that each column is biased to a level determined by the brightness count of the respective counter.
97 Citations
6 Claims
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1. A system for applying various voltage levels of a ramp voltage to the individual columns of pixels in a display device having a matrix of pixels arranged vertically in columns and horizontally in rows comprising:
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a plurality of voltage responsive signal transfer means individually actuating said columns of pixels, said signal transfer means simultaneously receiving said ramp voltage whereby pixel columns actuated by conductive signal transfer means are charged to voltage levels proportional to the level of said ramp voltage; means for providing an analog information signal having brightness levels for controlling the brightness of said pixels; means for receiving said analog information signal and providing digital brightness signals individually indicative of said brightness levels; digital storage means for receiving and storing said digital brightness signals, said digital storage means including a plurality of digital storage sets, each of said digital storage sets having a plurality of serially loaded digital storage segments, each of said digital storage segments storing said grey scale codes for one of said columns of pixels to individually provide said brightness signals to said columns; a plurality of counter means individually responsive to said digital storage segments for receiving said digital brightness signals as brightness counts for each of said columns, whereby said counter means are set to counts equal to said brightness levels and are set to count to zero, said counter means individually actuating said voltage reponsive signal transfer means whereby each of said signal transfer means is conductive when the associated counter is counting and nonconductive when the associated counter reaches zero whereby the pixels of individual columns are charged to various voltage levels of said ramp voltage in accordance with said brightness levels. - View Dependent Claims (2, 3)
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4. In a display device, having a matrix of picture elements arranged in m rows and n columns, for displaying a picture in response to a video signal including brightness information for each of said picture elements, a drive circuit comprising:
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analog-to-digital converter means for converting said video signal into digital grey scale codes for each of said picture elements; digital storage means for receiving said grey scale codes for the picture elements in the respective columns, said digital storage means including a plurality of digital storage sets, each of said digital storage sets having a plurality of digital storage segments, each of said digital storage segments storing said grey scale codes for one of said columns, whereby said digital storage means includes n of said digital storage segments; digital counter means, individually responsive to said digital storage segments, for receiving said grey scale codes whereby said counters are set to counts representative of selected grey scales; latch circuit means, individually responsive to said digital counter means, said latch circuit means having a first output when the respective counter contains at least one count, and having a second output when the respective counter is empty; transmission gate means, individually responsive to said latch circuit means, said transmission gate means being on when the output of said latch circuit means is said first output, and off when the output of said latch circuit means is said second ouput; means for simultaneously providing a ramp voltage to all of said transmission gate means whereby the picture elements in the respective columns are charged to levels in accordance with said grey scale codes in said counters; and means for sequentially scanning said rows to sequentially apply said ramp voltage to said rows of picture elements whereby said picture is generated in a plurality of lines times, and wherein said grey scale codes are transferred to said digital storage means during a first line time and said ramp voltage is provided during a second line time. - View Dependent Claims (5, 6)
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Specification