Patent ID: 8449129

Claim:
An LED based illumination device, comprising: a color conversion cavity comprising a first surface area including a first wavelength converting material and a second surface area including a second wavelength converting material; a first LED configured to receive a first current, wherein light emitted from the first LED enters the color conversion cavity and primarily illuminates the first wavelength converting material, the first wavelength converting material is physically separated from a light emitting surface of the first LED, wherein a light emitted from the LED based illumination device based on the light emitted from the first LED has a color temperature of less than 1,800 Kelvin; a second LED configured to receive a second current, wherein light emitted from the second LED enters the color conversion cavity and primarily illuminates the second wavelength converting material, the second wavelength converting material is physically separated from a light emitting surface of the second LED, wherein a light emitted from the LED based illumination device based on light emission from the second LED has a color temperature of less than 5,000 Kelvin; wherein the first current and the second current are selectable to achieve a range of correlated color temperature (CCT) of light output by the LED based illumination device; and an output window over an output port of the color conversion cavity, the output window comprising at least one of the first wavelength converting material and the second wavelength converting material, wherein the color conversion cavity is configured to mix a first light emitted from the first LED and converted by the first wavelength converting material with a second light emitted from the second LED and converted by the second wavelength converting material to produce a combined light that is emitted through the output window.