Patent ID: 7952784
Filing Date: 2011-05-31
Classification: H05B

Abstract:
1. Method for periodically emitting light of a predefined mixed color locus, comprising: mixing light constituted of at least two primary colors by energizing at least two different respective primary color light sources; said light sources being energized in a cyclic pulse-width modulated mode; and implementing said cyclic pulse-width within a cycle period in which said at least two different primary light sources are energized temporally offset relative to each other; wherein the light sources for initially two said primary colors and thereafter for the third of the primary colors and for a further light color, such as white light, are, in each instance, energized in pairs, both periodically in a temporally alternating mode and in a temporally overlapping mode; a cyclic pulse-width-modulated switching-on of the constant current pulses for the primary colors being implemented over the entire duration of the respective period successively in a phase-offset mode with respect to one another; and in each case at the period beginning with varying trailing edge, in the period centre with leading and trailing edges which are variable synchronously in opposition and at the period end with a varying leading edge of the current pulses; and wherein the overall brightness of a resulting mixed color locus is variable by changing the period length while maintaining a ratio of the switch-on time of a current pulse to the period duration.