Patent ID: 6069598
Filing Date: 2000-05-30
Classification: G09G

Abstract:
A field emission display device comprising:a light sensor generating an output signal proportional to sensed light, said output signal being variable;a converter circuit for generating a brightness signal responsive to said output signal, said brightness signal being variable;a plurality of column drivers each coupled to a respective column line, said column drivers for driving amplitude modulated voltage signals over column lines to provide a gray-scale level;a plurality of row drivers each coupled to a respective row line, said plurality of row drivers for driving a first voltage signal over one row line and at least three column lines;a horizontal synchronization clock signal for synchronizing the refresh of individual row lines; anda brightness control circuit for regulating the brightness of said field emission display device, said brightness control circuit coupled to receive said variable brightness signal and coupled to enable said plurality of row drivers, said brightness control circuit for generating said first voltage signal with a row on-time pulse width that is modulated in proportion to said variable brightness signal and generated in synchronization with said horizontal synchronization clock signal, said row on-time pulse width adapted to prevent degradation of said gray-scale level for said amplitude modulated voltage signals over said column lines.