Gamma correction of the viewing angle of liquid crystal display
AssigneesUniversal Avionics Systems Corporation, Instrument Division and L-3 Communications
InventorsJoseph W. Goode, III, James D. Cleland, James M. Brannen
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Abstract
The present invention is directed to a method and apparatus for adjusting the viewing angle of a liquid crystal display. In a preferred embodiment of the present invention, a plurality of digital-to-analog converters are arranged in pairs which have a fixed relationship. By determining appropriate values for the digital-to-analog converters, a desired viewing angle may be obtained for a liquid crystal display.
Claims1
A method for determining values of digital-to-analog converters for steering of the viewing angle of a liquid crystal display, said method comprising:
- providing a first set of digital-to-analog converters that are in electrical communication with at least one light source;
- providing a second set of digital-to-analog converters that are in electrical communication with said at least one light source;
- arranging said digital-to-analog converters in pairs, each of said pairs comprising a respective one of said digital-to-analog converters of said first set and a respective one of said digital-to-analog converters of said second set;
- driving said at least one light source with said first set of digital-to-analog converters to produce a first light output;
- driving said at least one light source with said second set of digital-to-analog converters to produce a second light output;
- determining a relationship of said pairs of said digital-to-analog converters such that said first light output and said second light output are balanced;
- driving said at least one light source with said first set and said second set of digital-to-analog converters to produce a third light output;
- determining an equation approximating said third light output;
- providing a desired viewing angle and a desired input gamma correction;
- determining a gamma correction of said relationship of said pairs of said digital-to-analog converters, said gamma correction being a function of said desired input gamma correction;
- determining an offset caused by said desired viewing angle, said offset being a level of light output as a function of said desired viewing angle;
- determining a center number, said center number being a percentage of said third light output at a predetermined point of said equation taking into account said offset;
- determining a first value of a first one of said digital-to-analog converters in each of said pairs, said first value being a function of said gamma correction, said offset, and said center number;
- and
- determining a second value of a second one of said digital-to-analog converters in each of said pairs, said second value being a function of said first value in each of said pairs.
Dependencies are inferred from the claim text.