Communications: electrical – Land vehicle alarms or indicators – Internal alarm or indicator responsive to a condition of the...
Patent
1987-10-08
1989-09-26
Brigance, Gerald L.
Communications: electrical
Land vehicle alarms or indicators
Internal alarm or indicator responsive to a condition of the...
340802, 340805, 350332, 350333, G09G 336
Patent
active
048703982
ABSTRACT:
A ferroelectric liquid crystal matrix display drive waveform scheme and circuit are disclosed which produce a resultant waveform at each pixel defined by the intersections of row and column electrodes that varies among three levels during each strobe interval. In a matrix of N rows and M columns, the rows are serially strobed with a strobe waveform that varies through three levels to provide select and non-select strobe signals. During each strobe interval, the column driver circuitry generates three-level and three-phase, time-variant drive waveforms. The circuit can provide up (write) and down (erase) pulses selectively to each pixel of the display using standard twisted-nematic type liquid crystal display drivers. A complex waveform generator provides three-level, three-phase control signals to the supply voltage inputs of the drivers. Timing and synchronizing signals are extracted from the graphics data and timing source outputs to enable the multilevel, multiphase signals to produce the three-phase resultant waveforms at each pixel in a sequence that correctly switches the display state of each pixel in accordance with the data without flicker and with uniform high contrast.
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Shimoda et al, "Optimum Bias Condition for Multiplex Driving of the Chiral Smectic C LCD," Japan Display (1986), pp. 460-462.
Brigance Gerald L.
Hjerpe Richard
McCollom Alan T.
Tektronix Inc.
Winkelman John D.
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