Importance

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Abstract

A system for color balancing within a liquid crystal flat panel display unit. The present invention includes a method and system for altering the brightness of two or more light sources, having differing color temperatures, thereby providing color balancing of a liquid crystal display (LCD) unit within a given color temperature range. The embodiments operate for both edge and backlighting systems. In an embodiment, two planar light pipes are positioned, a first over a second, with an air gap between. The first light pipe is optically coupled to receive light from a first light source having a color temperature above the predetermined range and the second light pipe is optically coupled to receive light from a second light source having a color temperature below the predetermined range. The color temperatures of the first and second light sources are selected such that the overall color temperature of the LCD can vary within the predetermined range by altering the driving voltages of the first and second light sources. In another embodiment, four light sources are used, two with each of the two light pipes. Another embodiment includes two light sources, of the same color temperature, associated with one light pipe and a third, variable intensity, light source with a second light pipe. Yet another embodiment includes a single light pipe associated with four light sources. A low profile embodiment includes two light sources and two wedge-shaped light pipes. Separate light extraction patterns can be used on the light pipes.

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First Claim