Patent ID: 7339332

Claim:
An electro-optical apparatus, comprising: a first group of LEDs configured to emit light of a first color, a second group of LEDs configured to emit light of a second color, and a third group of LEDs configured to emit light of a third color; one or more sensors optically coupled to the LEDs and configured to measure quantities S 1 , S 2 and S 3 proportional to the intensities of light emitted from the first, second, and third groups of LEDs respectively; electronic circuitry coupled to the one or more sensors and the groups of LEDs for receiving S 1 , S 2 and S 3 , K 1 , K 2 , and K 3 , and L C , and determining D 1 =L C −K 1 *S 1 , D 2 =L C −K 2 *S 2 , and D 3 =L C −K 3 *S 3 , where D 1 , D 2 , and D 3 determine current drive levels for the first, second, and third group of LEDs respectively, L C is a commanded luminance signal determining overall luminance produced by the LEDs and K 1 , K 2 , and K 3 are chrominance parameters for determining the relative light output from the first, second, and third group of LEDs respectively.