Patent ID: 8779685

Claim:
A white light emitting device comprising: at least one blue solid state light emitter operable to generate blue light with a dominant wavelength in a range 400 nm to 480 nm; at least one phosphor material operable to absorb a portion of the blue light and to emit light with a dominant wavelength in a range 490 nm to 590 nm; and at least one red solid state light emitter operable to generate red light with a dominant wavelength in a range 600 nm to 700 nm, wherein an emission product of the white light emitting device comprises combined light generated by the blue and red light emitters and light generated by the at least one phosphor material and appears white in color; and a drive circuit operable to compensate for variation in a ratio of red to blue light in the emission product such that over an operating temperature range of at least 25° C., said variation is less than 20%.