Illumination Device Including a Color Selecting Panel for Recycling Unwanted Light

• US 20080158873A1
• Filed: 12/29/2006
• Published: 07/03/2008
• Est. Priority Date: 12/29/2006
• Status: Active Grant

• Current Assignee: Signify North America Corporation (Signify N.V.)
• Original Assignee: Philips Lumileds Lighting Company LLC (Apollo Global Management, Inc.)
• Inventors: Harbers, Gerard, Bierhuizen, Serge J.
• Granted Patent: US 7,845,822 B2
• Time in Patent Office: Days
• US Class Current: 362/230
• CPC Class Codes: G02B 27/102 for generating a colour image from monochromatic image signal sources
• CPC Class Codes: H04N 9/3108 by using a single electronic spatial light modulator
• CPC Class Codes: H04N 9/3111 for displaying the colours sequentially, e.g. by using sequentially activated light sources sequential projection in colour photography G03B33/08
• CPC Class Codes: H04N 9/3158 for controlling the spectrum

Abstract

An illumination source includes at least one light emitting diode, e.g., in array of LEDs that produce short wavelength light. One or more wavelength converting elements, such as phosphor elements, convert at least a portion of the short wavelength light from the LED(s) to longer wavelengths, such as Red and Green. A dichroic element positioned between the LED(s) and the wavelength converting element(s) transmits the light from the LED(s) and reflects the longer wavelengths from the wavelength converting element(s). A color selection panel selects the colors of light to be produced by the illumination device and to be recycled for another opportunity to be converted by the wavelength converting element(s) or to be reflected by the dichroic element. The color selection panel may operate in one or both of the spatial domain and the temporal domain.

Claims

1. An illumination device comprising:

at least one light emitting diode that produces light having a first range of wavelengths;

at least one wavelength converting element converting at least a portion of the light having the first range of wavelengths to light having a second range of wavelengths; and

a color selecting panel to select light within one or more color ranges to be produced by the illumination device and select light of other color ranges to be recycled, wherein the selection of the color ranges of light to be produced and to be recycled is in at least one of the spatial domain and the temporal domain.

2. The illumination device of claim 1, further comprising a dichroic element positioned between the array of light emitting diodes and the at least one wavelength converting element, the dichroic element transmitting light having the first range of wavelengths and reflecting light having the second range of wavelengths.

3. The illumination device of claim 1, wherein the at least one light emitting diode is an array of light emitting diodes.

4. The illumination device of claim 1, further comprising:

a collimator between the at least one wavelength converting element and the color selecting panel.

5. The illumination device of claim 1, further comprising:

a concentrator element between the at least one light emitting diode and the at least one wavelength converting element.

6. The illumination device of claim 2, further comprising:

a second at least one light emitting diode;

a second at least one wavelength converting element converting at least a portion of the light from the second at least one light emitting diode; and

a second dichroic element positioned to receive and combine the light converted by the at least one wavelength converting element and the light converted by the second at least one wavelength converting element;

wherein the color selecting panel is positioned to receive the light combined by the second dichroic element.

7. The illumination device of claim 1, wherein the at least one wavelength converting element comprises a wavelength converting ceramic.

8. The illumination device of claim 1, wherein the light having the first range of wavelengths is Blue light and the light having a second range of wavelengths includes Green light and Red light.

9. The illumination device of claim 8, wherein the at least one wavelength converting element comprises a first wavelength converting element that converts at least a portion of the light having the first range of wavelengths to Red light and a second wavelength converting element that converts at least a portion of the light having the first range of wavelengths to Green light.

10. The illumination device of claim 1, wherein a portion of the light to be recycled that has wavelengths within the first range or wavelengths is recycled by being received by the at least one wavelength converting element and being converted to light having the second range of wavelengths and another portion of the light to be recycled that has wavelengths within the second range of wavelengths is recycled by being reflected by the dichroic element.

11. The illumination device of claim 1, wherein the color selecting panel selects the color ranges to produce and the color ranges to recycle in a spatial domain so that different locations on the color selecting panel selects different color ranges to be produced and different color ranges to be recycled.

12. The illumination device of claim 1, wherein the color selecting panel selects the color ranges to produce and the color ranges to recycle in a temporal domain so that the same color range is selected to be produced and the same color range is selected to be recycled at all locations of the color selecting panel at one time and that the color range selected to be produced and the color range selected to be recycled change with time.

13. The illumination device of claim 1, wherein the color selecting panel selects the color ranges to produce and the color ranges to recycle in a spatial domain and a temporal domain so that different locations on the color selecting panel selects different color ranges to be produced and different color ranges to be recycled and that the color range selected to be produced and the color range selected to be recycled at the different locations changes with time.

14. A method of producing light from an illumination source, the method comprising:

generating Blue light from at least one light emitting diode;

converting at least a portion of the Blue light from the at least one light emitting diode to produce Red light and Green light; and

selecting the colors of light to produce, wherein the non-selected colors are recycled.

15. The method of claim 14, wherein the Blue light is generated from an array of light emitting diodes.

16. The method of claim 14, further comprising transmitting the Blue light through a filter prior to converting at least a portion of the Blue light from the at least one light emitting diode to produce Red light and Green light, wherein the filter reflects the Red light and the Green light.

17. The method of claim 16, wherein when the non-selected color is Blue, the Blue light is recycled by being converted to produce Red light and Green light, and wherein the non-selected color is Red or Green, the Red light or Green light is recycled by being reflected by the filter.

18. The method of claim 14, wherein selecting the color of light to produce is performed in at least one of the spatial domain and the temporal domain.

19. The method of claim 18, wherein selecting the color of light to produce is performed in the spatial domain so that the color of light produced by the illumination source varies over space.

20. The method of claim 18, wherein selecting the color of light to produce is performed in the temporal domain so that the color of light produced by the illumination source varies over time.

21. The method of claim 18, wherein selecting the color of light to produce is performed in the spatial domain and the temporal domain so that the color of light produced by the illumination source varies over space and time.

22. The method of claim 14, wherein converting at least a portion of the Blue light from the at least one light emitting diode further produces Yellow light, the method further comprising:

generating Blue light from a second at least one light emitting diode;

converting a portion of the Blue light from the second at least one light emitting diode to produce Cyan light; and

combining the Blue light, Cyan light, Red light, Yellow light and Green light prior to selecting the colors of light to produce from the illumination source.