Light modulator assembly

• US 7,126,741 B2
• Filed: 08/12/2004
• Issued: 10/24/2006
• Est. Priority Date: 08/12/2004
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Childers, Winthrop D., Wagner, William R.
• Primary Examiner(s): Lester, Evelyn A.
• Application Number:
  US10/917,128
• Publication Number:
  US 20060033980A1
• Time in Patent Office: 803 Days
• Field of Search: 359290-295, 359/298, 359/302, 359/303, 359/318, 359/223, 359/224, 359/279, 359/245, 359/247, 359/726, 359/727, 250/370.15, 257/431, 257/443, 349/161, 62/37
• US Class Current: 359/290
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 7/008 with means for compensating for changes in temperature or for controlling the temperature; thermal stabilisation
• CPC Class Codes: G02B 7/181 with means for compensating for changes in temperature or for controlling the temperature; thermal stabilisation

Abstract

A light modulator assembly includes a substrate, a micro-electro mechanical semiconductor device (MEMS device) formed on the substrate, and a temperature control device coupled to the substrate and configured to maintain the MEMS device at or above an elevated threshold temperature.

Claims

1. A light modulator assembly, comprising:

a micro-electro mechanical semiconductor device (MEMS device) formed an a substrate;

a light engine for illuminating said MEMS device; and

a temperature control device thermally coupled to said substrate and configured to heat said MEMS device during operation of said MEMS device and to maintain said MEMS device at or above an elevated threshold temperature, said temperature control device being separate from said light engine.

2. The light modulator assembly of claim 1, wherein said MEMS device comprises a diffractive light device (DLD).

3. The light modulator assembly of claim 2, wherein said DLD is an interferometric DLD.

4. The light modulator assembly of claim 1, wherein said temperature control device includes a resistive heater.

5. The light modulator assembly of claim 4, wherein said resistive heater comprises a thin-film resistive heater.

6. The light modulator assembly of claim 4, wherein said resistive heater is configured to provide information about a temperature of said assembly.

7. The light modulator assembly of claim 1, wherein said temperature control device includes a resistive heater and a heat sink.

8. The light modulator assembly of claim 7, wherein said heat sink includes cooling fins.

9. The light modulator assembly of claim 1, wherein said MEMS devices is specifically calibrated for operation at or above said elevated threshold temperature rather than at a lesser ambient temperature.

10. The light modulator assembly of claim 1, further comprising a controller for determining a temperature of said MEMS device and controlling said temperature control device to selectively heat said MEMS device to maintain said MEMS device at or above said elevated threshold temperature.

11. The light modulator assembly of claim 10, wherein said controller uses information about a duty cycle of said light modulator assembly to determine how much heat should be applied to heat said light modulator assembly.

12. The light modulator assembly of claim 1, wherein said elevated threshold temperature corresponds to a black state temperature of said MEMS device.

13. The light modulator assembly of claim 12, further comprising a device coupled to said MEMS device that lowers said black state temperature of said MEMS device.

14. The light modulator assembly of claim 13, wherein said device that lowers said black state temperature comprises cooling fins.

15. The light modulator assembly of claim 1, wherein a separate temperature control device is provided for each element of said MEMS device corresponding to a pixel in a display.

16. A light modulator assembly, comprising:

a substrate;

a micro-electro mechanical semiconductor device (MEMS device) formed on said substrate; and

a temperature control device coupled to said substrate and configured to both selectively heat or cool said MEMS device during operation of said MEMS device to maintain said operating MEMS device above an elevated threshold temperature and below an upper threshold temperature.

17. The light modulator assembly of claim 16, wherein said temperature control device includes a thermoelectric heat transfer device.

18. The light modulator assembly of claim 16, wherein said temperature control device includes a Peltier junction.

19. The light modulator assembly of claim 16, wherein said MEMS device is specifically calibrated for operation at or above said elevated threshold temperature rather than at a lesser ambient temperature.

20. The light modulator assembly of claim 16, further comprising a controller for determining a temperature of said MEMS device and controlling said temperature control device to selectively heat or cool said MEMS device to maintain said MEMS device above said elevated threshold temperature and below said upper threshold temperature.

21. The light modulator assembly of claim 20, wherein said controller uses information about a duty cycle of said light modulator assembly to determine how much heat should be applied to heat said light modulator assembly.

22. The light modulator assembly of claim 16, wherein said elevated threshold temperature corresponds to a black state temperature of said MEMS device.

23. The light modulator assembly of claim 16, wherein a separate temperature control device is provided for each element of said MEMS device corresponding to a pixel in a display.

24. A light modulator assembly, comprising:

a substrate;

a micro-electro mechanical semiconductor device (MEMS device) formed on said substrate; and

a temperature control device coupled to said substrate and configured to both selectively heat or cool said MEMS device to maintain said MEMS device within a predetermined, elevated temperature range.

25. The light modulator assembly of claim 24, wherein said temperature control device includes a thermoelectric heat transfer device.

26. The light modulator assembly of claim 24, wherein said MEMS device is specifically calibrated for operation in said elevated temperature range rather than at a lesser ambient temperature.

27. The light modulator assembly of claim 24, further comprising a controller for determining a temperature of said MEMS device and controlling said temperature control device to selectively heat or cool said MEMS device to maintain said MEMS device within said predetermined, elevated temperature range.

28. The light modulator assembly of claim 27, wherein said controller uses information about a duty cycle of said light modulator assembly to determine how much beat should be applied to heat said light modulator assembly.

29. The light modulator assembly of claim 24, wherein said elevated temperature range corresponds to a black state temperature of said MEMS device.

30. The light modulator assembly of claim 29, further comprising a device coupled to said MEMS device that lowers said black state temperature of said MEMS device.

31. The light modulator assembly of claim 30, wherein said device that lowers said black state temperature comprises cooling fins.

32. The light modulator assembly of claim 24, wherein a separate temperature control device is provided for each clement of said MEMS device corresponding to a pixel in a display.

33. A method of forming a light modulator assembly, comprising:

forming a plurality of micro-electromechanical system (MEMS) devices configured to operate within an elevated temperature range;

coupling at least one temperature control device to at least one of said MEMS devices, wherein said temperature control device is configured to both selectively heat or coal said MEMS device to maintain said MEMS device within said elevated temperature range.

34. The method of claim 33, wherein said MEMS device is configured to output light in a controlled frequency in response to being exposed to broadband light.

35. The method of claim 34, wherein said MEMS device is a diffractive light device.

36. The light modulator assembly of claim 33, wherein said MEMS device is specifically calibrated for operation in said elevated temperature range rather than at a lesser ambient temperature.

37. The light modulator assembly of claim 33, further comprising a controller for determining a temperature of said MEMS device and controlling said temperature control device to selectively heat or cool said MEMS device to maintain said MEMS device within said elevated temperature range.

38. The light modulator assembly of claim 37, wherein said controller uses information about a duty cycle of said light modulator assembly to determine how much heat should be applied to heat said light modulator assembly.

39. The light modulator assembly of claim 33, wherein said elevated temperature range corresponds to a black state temperature of said MEMS device.

40. The light modulator assembly of claim 39, further comprising a device coupled to said MEMS device that lowers said black state temperature of said MEMS device.

41. The light modulator assembly of claim 40, wherein said device that lowers said black state temperature comprises cooling fins.

42. The light modulator assembly of claim 33, wherein a separate temperature control device is provided for each element of said MEMS device corresponding to a pixel in a display.

43. A light modulator assembly, comprising:

means for modulating light;

means for illuminating said means for modulating light; and

means, thermally coupled to said means for modulating light, for heating said means for modulating light and maintaining said means for modulating light above an elevated threshold temperature during operation of said means for modulating light, wherein said means for heating are separate from said means for illuminating.

44. The light modulator assembly of claim 43, and further comprising means for maintaining said means for modulating light below an upper control temperature.

45. The light modulator assembly of claim 43, wherein said means for modulating light are specifically calibrated for operation at or above said elevated threshold temperature rather than at a lesser ambient temperature.

46. The light modulator assembly of claim 43, further comprising means for determining a temperature of said means for modulating light and for controlling said means for heating to selectively heat said means for modulating light to said elevated threshold temperature.

47. The light modulator assembly of claim 46, wherein said means for determining a temperature of said means for modulating light also uses information about a duty cycle of said means for modulating light to determine how much heat should be applied to heat said moans for modulating light.

48. The light modulator assembly of claim 43, wherein said elevated threshold temperature corresponds to a black state temperature of said means for modulating light.

49. The light modulator assembly of claim 48, further comprising means for lowering said black state temperature of said means for modulating light.