LED illumination device with color converting surfaces

1. 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 primarily illuminates the first wavelength converting material, wherein a light emitted from the LED based illumination device based on the light emitted from the first LED has a first color temperature;

a second LED configured to receive a second current, wherein light emitted from the second LED primarily illuminates the second wavelength converting material, wherein a light emitted from the LED based illumination device based on light emission from the second LED has a second color temperature that is different than the first color temperature;

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.

2. The LED based illumination device of claim 1 , wherein the second LED and the second wavelength converting material are configured to produce a color point of the light emitted from the LED based illumination device that is within a degree of departure Δxy of 0.010 from a target color point in a CIE 1931 xy diagram when the second current is supplied to the second LED and the first current is substantially zero.

3. The LED based illumination device of claim 1 , wherein the first wavelength converting material and the second wavelength converting material are included as part of one or more transmissive layers disposed above the first LED and the second LED.

4. The LED based illumination device of claim 1 , wherein the first LED and the second LED each emit light with a peak emission wavelength within five nanometers of each other.

5. The LED based illumination device of claim 1 , wherein more than fifty percent of light emitted from the first LED is directed to the first surface area, and wherein more than fifty percent of light emitted from the second LED is directed to the second surface area.

6. The LED based illumination device of claim 1 , further comprising:

a third LED configured to receive a third current, wherein light emitted from the third LED primarily illuminates a third wavelength converting material, wherein a light emitted from the LED based illumination device based on the light emitted from the third LED has a third color temperature that is different than the first color temperature and the second color temperature.

7. The LED based illumination device of claim 6 , wherein the first, second, and third LEDs each emit light with a peak emission wavelength within five nanometers of each other.

8. The LED based illumination device of claim 6 , wherein the first LED and the first wavelength converting material are configured to produce light that is emitted from the LED based illumination device with a color point below a Planckian locus in CIE 1931 color space, and wherein the third LED and the third wavelength converting material are configured to produce light that is emitted from the LED based illumination device with a color point above the Planckian locus in the CIE 1931 color space.

9. 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 primarily illuminates the first wavelength converting material, wherein a light emitted from the LED based illumination device based on the light emitted from the first LED has a first color temperature;

a second LED configured to receive a second current, wherein light emitted from the second LED primarily illuminates the second wavelength converting material, wherein a light emitted from the LED based illumination device based on light emission from the second LED has a second color temperature that is different than the first color temperature, 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.

10. The LED based illumination device of claim 9 , wherein one or more transmissive elements includes the first surface area including the first wavelength converting material and the second surface area including the second wavelength converting material, wherein the one or more transmissive elements are disposed above the first LED and the second LED.

11. The LED based illumination device of claim 10 , wherein the one or more transmissive elements includes a third surface area including a third wavelength converting material disposed above a third LED configured to receive a third current, wherein light emitted from the third LED primarily illuminates the third wavelength converting material.

12. The LED based illumination device of claim 11 , wherein the first, second, and third LEDs each emit light with a peak emission wavelength within five nanometers of each other.

13. The LED based illumination device of claim 11 , wherein a light emitted from the LED based illumination device based on the light emitted from the first LED has a color point below a Planckian locus in CIE 1931 color space, and wherein the light emitted from the LED based illumination device based on the light emitted from the third LED has a color point above the Planckian locus in the CIE 1931 color space.

14. An LED based illumination device, 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 primarily illuminates the first wavelength converting material, wherein a light emitted from the LED based illumination device based on the light emitted from the first LED has a first color temperature;

a second LED configured to receive a second current, wherein light emitted from the second LED primarily illuminates the second wavelength converting material, wherein a light emitted from the LED based illumination device based on light emission from the second LED has a second color temperature that is different than the first color temperature, 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 the first and second surface areas comprising at least one of the first wavelength converting material and the second wavelength converting material, wherein a 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.

15. The LED based illumination device of claim 14 , wherein the second LED and the second wavelength converting material are configured to produce a color point of the light emitted from the LED based illumination device that is within a degree of departure Δxy of 0.010 from a target color point in a CIE 1931 xy diagram when the second current is supplied to the second LED and the first current is substantially zero.

16. The LED based illumination device of claim 14 , wherein the first wavelength converting material and the second wavelength converting material are included as part of one or more transmissive layers disposed above the first LED and the second LED.

17. The LED based illumination device of claim 14 , wherein the first LED and the second LED each emit light with a peak emission wavelength within five nanometers of each other.

18. The LED based illumination device of claim 14 , further comprising:

a third LED configured to receive a third current, wherein light emitted from the third LED primarily illuminates a third wavelength converting material, wherein a light emitted from the LED based illumination device based on the light emitted from the third LED has a third color temperature that is different than the first color temperature and the second color temperature.

19. The LED based illumination device of claim 18 , wherein the first, second, and third LEDs each emit light with a peak emission wavelength within five nanometers of each other.

20. The LED based illumination device of claim 18 , wherein the first LED and the first wavelength converting material are configured to produce light that is emitted from the LED based illumination device with a color point below a Planckian locus in CIE 1931 color space, and wherein the third LED and the third wavelength converting material are configured to produce light that is emitted from the LED based illumination device with a color point above the Planckian locus in the CIE 1931 color space.