US 4,378,556 AGranted

Gray shade operation of sequentially addressed AC plasma panel

AssigneeUnited Technologies Corporation

InventorRobert E. Wisnieff

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Abstract

A circuit configuration for use with a small plasma panel to allow independent variation of the brightness level on a raster in addition to the information displayed by the raster. The gray scale level of all or part of the displayed information can be changed in response to a change in a sensed condition. The desired gray shade level or levels for a particular raster of digital information is stored in a simple memory. The data out of the memory is used by an E/W pulse gate to clock write pulses and erase pulses to the addressing circuitry of the plasma panel. The write or erase pulses then combine with the sustainer voltage waveform at each site to either strike, entinguish, or not change discharge state of each site as the plasma panel as the individual site locations are sequentially addressed.

Claims6

Dependent claims

A gray scale circuit for causing apparent intensity variations on a plasma panel which has a number of row electrodes and a number of column electrodes, the intersection of which defines a discharge site, comprising:

video means for generating a digital video signal that has been quantized into a predetermined number of levels in a raster format for presentation on said plasma panel;
pulse means for generating a plurality of erase pulses, and a plurality of write pulses;
decoder means for addressing said plurality of column electrodes and said plurality of row electrodes in a synchronous manner;
storage means connected to said video means including one recirculating means for every two of said two levels of said predetermined number of levels, each of which is sized for storing at least one raster of video information;
gate means including a pair of AND gates connected to each recirculating shift register in said storage means for gating selected ones of said erase pulses and write pulses to each of said discharge sites in said plasma panel at the same time each discharge site is being addressed by said decoder means;
and
whereby each of said discharge sites is written and erased for a predetermined interval during a flicker period so as to display gray scale variation.

4 more elements

Dependencies are inferred from the claim text.