High power lamp cooling

Abstract

Light sources include an electrodeless bulb having an interior, a fill contained within the interior of the bulb, an excitation structure that transmits electromagnetic energy to the fill in the bulb, and cooling fins extending radically outward from the bulb. The fill is excited by the electromagnetic energy to a plasma state that causes light emission and generates heat energy. The cooling fins, when rotated, draw air toward the bulb to cool the bulb. Alternatively, cooling may be provided by a rotatable squirrel cage about an electrodeless bulb. The light sources can be used in display systems, such as field sequential color systems.

What is claimed is: 
     
       1. A light source comprising: a bulb having an interior;   a fill contained within the interior; and   a fin extending from the bulb to draw air past the bulb when rotated.   
     
     
       2. The light source of claim 1, further comprising additional fins. 
     
     
       3. The light source of claim 2, wherein the fill, upon excitation, emits light. 
     
     
       4. The light source of claim 2, wherein the fins are integral with the bulb. 
     
     
       5. The light source of claim 2, wherein the bulb comprises quartz. 
     
     
       6. The light source of claim 2, wherein the bulb comprises a quartz envelope. 
     
     
       7. The light source of claim 2, wherein the bulb comprises a quartz sphere. 
     
     
       8. The light source of claim 2, further comprising a reflector adjacent the bulb to direct light from the bulb. 
     
     
       9. The light source of claim 2, wherein the fins extend radically outward from the bulb. 
     
     
       10. The light source of claim 2, wherein the fins cause the bulb to be cooled when rotated. 
     
     
       11. The light source of claim 2, wherein the fins are shaped to draw air when rotated. 
     
     
       12. The light source of claim 2, further comprising a rotator to rotate the bulb. 
     
     
       13. The light source of claim 2, wherein the fill achieves a plasma state upon excitation with electromagnetic energy. 
     
     
       14. The light source of claim 13, wherein the electromagnetic energy comprises microwave energy. 
     
     
       15. The light source of claim 13, wherein the electromagnetic energy comprises radio frequency energy. 
     
     
       16. The light source of claim 2, further comprising a cavity, wherein the bulb is disposed in a cavity. 
     
     
       17. The light source of claim 16, further comprising an electromagnetic source and a waveguide coupled between the electromagnetic source and the cavity to provide excitation energy to the fill. 
     
     
       18. The light source of claim 17, wherein the waveguide is arranged to transmit electromagnetic energy to excite the fill to a plasma state. 
     
     
       19. The light source of claim 18, wherein the electromagnetic energy comprises microwave energy. 
     
     
       20. The light source of claim 17, wherein the electromagnetic source comprises a microwave source. 
     
     
       21. The light source of claim 17, wherein the electromagnetic source comprises a radio frequency source. 
     
     
       22. A light source comprising: a bulb having an interior;   a fill contained within the interior; and   a cage disposed about the bulb comprising fins extending from the cage to draw air past the bulb when rotated.   
     
     
       23. The light source of claim 22, wherein the cage comprises a squirrel cage. 
     
     
       24. A light source of claim 22, wherein the cage comprises spokes that couple between the cage and the bulb. 
     
     
       25. The light source of claim 22, wherein the cage comprises an end and the bulb comprises a shaft, and wherein the end and the shaft are coupled to be driven together to rotate the cage. 
     
     
       26. The light source of claim 22, wherein the cage further comprises spokes coupling the cage to the light bulb, and wherein rotation of the bulb causes rotation of the cage by virtue of the spokes coupling the cage to the bulb. 
     
     
       27. The light source of claim 22, wherein the fins are curved. 
     
     
       28. The light source of claim 22, wherein rotation of the cage causes air to move generally readily from the cage. 
     
     
       29. The light source of claim 22, wherein rotation of the cage cools the bulb. 
     
     
       30. The light source of claim 22, wherein the cage comprises openings that allow air to pass through. 
     
     
       31. A method of cooling a light source, the method comprising: rotating a bulb having fins extending from the bulb; and   drawing air past the bulb by action of the fins.   
     
     
       32. The method of claim 31, further comprising angling the fins on the bulb so as to draw the air. 
     
     
       33. The method of claim 31, wherein rotating the bulb comprises rotating a shaft attached to the bulb. 
     
     
       34. The method of claim 31, further comprising generating heat in the bulb to dissipate by rotation of the fins. 
     
     
       35. The method of claim 31, further comprising determining a number of the filters to be attached to the bulb based on a color change frequency associated with the colored light being a multiple of a frequency of rotation of the bulb.