Patent ID: 8253666

Claim:
An illumination control method for a plurality of light emitting diodes, the method comprising: monitoring an input control signal, wherein the input control signal designates a first intensity level for one or more first light emitting diodes having a first spectrum and a second intensity level for one or more second light emitting diodes having a second spectrum different from the first spectrum; determining a first temperature associated with the one or more first light emitting diodes; determining a second temperature associated with the one or more second light emitting diodes; retrieving a first plurality of parameters stored in a memory, wherein the first plurality of parameters designates a corresponding combination of a first electrical biasing and a second electrical biasing for the first temperature, wherein the first electrical biasing for the one or more first light emitting diodes is configured to produce a first wavelength shift, and wherein the second electrical biasing for the one or more first light emitting diodes is configured to produce a second wavelength shift that is opposed to the first wavelength shift; retrieving a second plurality of parameters stored in the memory, wherein the second plurality of parameters designates a corresponding combination of a third electrical biasing and a fourth electrical biasing for the second temperature, wherein the third electrical biasing for the one or more second light emitting diodes is configured to produce a third wavelength shift, and wherein the fourth electrical biasing for the one or more second light emitting diodes is configured to produce a fourth wavelength shift that is opposed to the third wavelength shift; processing the first plurality of parameters into a first input electrical biasing control signal for the one or more first light emitting diodes; processing the second plurality of parameters into a second input electrical biasing control signal for the one or more second light emitting diodes; operating the one or more first light emitting diodes with a first time-averaged modulation of forward current conforming to the first input electrical biasing control signal to provide a substantially constant first intensity level over a predetermined temperature range and having an emitted spectrum within a first predetermined variance of the first spectrum; and operating the one or more second light emitting diodes with a second time-averaged modulation of forward current conforming to the second input electrical biasing control signal to provide a substantially constant second intensity level over the predetermined temperature range having an emitted spectrum within a second predetermined variance of the second spectrum.