Patent ID: 8159150

Claim:
An illumination device for generating output light having a desired luminous flux and chromaticity, the illumination device comprising: (a) at least one first array of one or more light-emitting elements adapted to generate first light having a first spectral power distribution, and at least one second array of one or more light-emitting elements adapted to generate second light having a second spectral power distribution different than the first spectral power distribution, the output light being a combination of the first light and the second light; (b) a first current driver operatively coupled to the first array for selectively supplying electrical drive current to the first array based on a first control signal, and a second current driver operatively coupled to the second array for selectively supplying electrical drive current to the second array based on a second control signal; (c) an optical sensor for sensing a portion of the output light, the optical sensor configured to generate an optical signal representative of the mixed radiant flux of the output light; and (d) a controller operatively coupled to the first current driver, second current driver, and the optical sensor and configured to generate the first control signal and second control signal based at least on the characteristics of the first light and second light, respectively, and the desired luminous flux and chromaticity of the output light, wherein the first control signal at least in part configured using a first modification signal and the second control signal at least in part configured using a second modification signal, the controller being configured to electronically filter the optical signal based on the first modification signal and second modification signal thereby determining optical characteristics of the first light and second light, wherein the first control signal is a pulse width modulated signal or a pulse code modulated signal and the second control signal is a pulse width modulated signal or a pulse code modulated signal.