Spatial light modulators having photo-detectors for use in display systems

1. A spatial light modulator used in a display system for producing a color image by modulating a light beam having a multiplicity of sequential components of different frequencies, the spatial light modulator comprising:

a semiconductor substrate having a first photo-detector having a preferential spectral response to a first component of the multiplicity of components of the light beam and generating a timing signal according to which the spatial light modulator modulates the light beam.

2. The spatial light modulator of claim 1 , wherein the semiconductor substrate further comprises:

a second photo-detector having a preferential response to a second component of the multiplicity of components of the light beam and generating another timing signal.

3. The spatial light modulator of claim 2 , wherein the first and the second photo-detectors are positioned at different locations.

4. The spatial light modulator of claim 1 , wherein the first photo-detector comprises a color filtering film that passes the first component of the light beam and blocks the other components of the light beam.

5. The spatial light modulator of claim 3 , wherein the color filtering film comprises a polyimide or dye or polymer.

6. The spatial light modulator of claim 3 , wherein the color filtering film comprises a dichroic filter stack.

7. The spatial light modulator of claim 4 , wherein the color filtering film comprises a plurality of optical layers of different optical properties.

8. The spatial light modulator of claim 3 , wherein the semiconductor substrate further comprises:

a third photo-detector having a preferential spectral response to the light beam and generating a another timing signal; and

a differential amplifier in connection with the first and the third detectors for subtracting the timing signals from the first and third photo-detector and amplifying the difference between said timing signals.

9. The spatial light modulator of claim 4 , wherein the timing signals from the first and third photo-detector co-exist during a particular time period.

10. The spatial light modulator of claim 1 , wherein the semiconductor substrate further comprises:

an array of micromirrors for reflecting the light beam into different directions; and

an array of electrodes and circuitry for electrically deforming the micromirrors.

11. The spatial light modulator of claim 1 , further comprising:

a glass substrate having an array of micromirrors formed thereon for reflecting the light beam into different directions; and

wherein the semiconductor substrate further comprises:

an array of electrodes and circuitry for electrically deforming the micromirrors of the array on the glass substrate.

12. The spatial light modulator of claim 11 , wherein the semiconductor and glass substrates are bonded together.

13. A spatial light modulator, comprising:

an array of micromirrors for reflecting a light beam into different directions;

an array of electrodes and circuitry for deflecting the micromirrors; and

a photo-detector having a preferential spectral response to a component of the light beam with a particular frequency and generating a timing signal according to the detection for controlling the electrodes and circuitry.

14. The spatial light modulator of claim 13 , wherein the array of the micromirrors is disposed on a substrate that is transmissive to visible light, and the array of electrode and circuitry are disposed on another substrate on which the photo-detector is disposed.

15. The spatial light modulator of claim 13 , wherein the array of micromirrors, the array of electrode and circuitry and the photo-detector are disposed on the same substrate.

16. The spatial light modulator of claim 13 , further comprising:

a package substrate on which the micromirror array, electrode and circuitry array and the photo-detector are placed.

17. The spatial light modulator of claim 16 , further comprising: a package cover on the package substrate and hermetically sealed to the package substrate.

18. The spatial light modulator of claim 17 , wherein the package cover is glass that is transmissive to visible light.

19. The spatial light modulator of claim 13 , wherein the photo-detector further comprises: a color filtering film that passes the light component of the particular frequency and blocks other components of the incident light.

20. The spatial light modulator of claim 19 , wherein the color filtering film comprises polyimide or dye or polymer.

21. The spatial light modulator of claim 19 , wherein the color filtering film comprises a dichroic filter comprising multiple optical layers of different optical properties.

22. The spatial light modulator of claim 13 , further comprising:

another photo-detector having a preferential spectral response different from that of the first photo-detector; and

a differential amplifier in connection to the photo-detectors to subtract the outputs of the photo-detectors and amplify a difference between the outputs.

23. The spatial light modulator of claim 13 , further comprising:

another photo-detector;

wherein the incident light comprises a first and second component of different frequencies, the first and second components sequentially impinging the micromirror array;

wherein the photo-detector has a preferential spectral response to the first component of the incident light beam and generating a first timing signal corresponding to an arrival of the first component; and

wherein said another photo-detector has a preferential spectral response to the second component of the incident light generating a second timing signal corresponding to an arrival of the second component.

24. The spatial light modulator of claim 21 , wherein the first and second timing signals co-exist during a particular time period.

25. A projector, comprising:

a light source;

a collection lens that collects light from the light source and focuses the collected light onto a spatial light modulator, wherein the spatial light modulator further comprises:

an array of micromirrors for reflecting light from the collection lens either away from or onto a projection lens;

an array of electrodes and circuitry for deflecting the micromirrors; and

a photo-detector having a preferential spectral response to a component of the incident light beam with a particular frequency and generating a timing signal according to the spectral response for controlling the electrodes and circuitry; and

a projection lens positioned to collect the reflected light from the micromirrors and project the collected light onto a display target.

26. The projector of claim 25 , wherein the array of the micromirrors is disposed on a substrate that is transmissive to visible light, and the array of electrode and circuitry are disposed on another substrate on which the photo-detector is disposed.

27. The projector of claim 25 , wherein the array of micromirrors, the array of electrode and circuitry and the photo-detector are disposed on the same substrate.

28. The projector of claim 25 , further comprising:

a package substrate on which the micromirror array, electrode and circuitry array and the photo-detector are placed.

29. The projector of claim 28 , further comprising: a package cover on the package substrate and hermetically sealed to the package substrate.

30. The projector of claim 29 , wherein the package cover is glass that is transmissive to visible light.

31. The projector of claim 30 , wherein the photo-detector further comprises: a color filtering film that passes the light component of the particular frequency and blocks other components of the incident light.

32. The projector of claim 31 , wherein the color filtering film comprises polyimide or dye or polymer.

33. The projector of claim 31 , wherein the color filtering film comprises a dichroic filter comprising multiple optical layers of different optical properties.

34. The projector of claim 25 , further comprising:

another photo-detector having a preferential spectral response to all components of the incident light beam; and

a differential amplifier in connection to the photo-detectors to differentiate the responses of the photo-detectors and amplifies a difference between the detections.

35. The projector of claim 25 , further comprising:

another photo-detector;

wherein the incident light comprises a first and second component of different frequencies, the first and second components sequentially impinging the micromirror array;

wherein the photo-detector has a preferential spectral response to the first component of the incident light beam and generating a first timing signal corresponding to an arrival of the first component; and

wherein said another photo-detector has a preferential spectral response to the second component of the incident light beam generating a second timing signal corresponding to an arrival of the second component.

36. The projector of claim 33 , wherein the first and second timing signals co-exist during a particular time period.

37. A method for operating a spatial light modulator, comprising:

projecting a light beam onto the spatial light modulator through a collection lens;

detecting a component of the light beam with a particular frequency exiting from the collection lens;

generating a timing signal according to the detection; and

controlling the spatial light modulator in modulating the light beam based on the timing signal.

38. The method of claim 37 , further comprising:

detecting another component of the light beam with another particular frequency; and

generating another timing signal.

39. The method of claim 38 , further comprising:

subtracting the timing signals; and

amplifying the subtraction.

40. A display system, comprising:

a light source;

a collection lens that collects a light beam from the light source and focusing the collected light beam onto a spatial light modulator;

the spatial light modulator that modulates the incident light beam;

a photo-detector having a preferential spectral response to a component of the light beam with a particular frequency and generating a timing signal according to the response for controlling the modulation of the spatial light modulator; and

a projection lens for collecting the modulated light beam and projecting the collected light beam onto a display target.

41. The projector of claim 40 , wherein the array of the micromirrors is disposed on a substrate that is transmissive to visible light, and the array of electrode and circuitry are disposed on another substrate on which the photo-detector is disposed.

42. The projector of claim 40 , wherein the array of micromirrors, the array of electrode and circuitry and the photo-detector are disposed on the same substrate.

43. The projector of claim 40 , further comprising:

a package substrate on which the micromirror array, electrode and circuitry array and the photo-detector are placed.

44. The projector of claim 40 , wherein the photo-detector further comprises: a color filtering film that passes the light component of the particular frequency and blocks other components of the incident light.

45. The projector of claim 44 , wherein the color filtering film comprises polyimide or dye or polymer.

46. The projector of claim 44 , wherein the color filtering film comprises a dichroic filter comprising multiple optical layers of different optical properties.

47. The projector of claim 40 , further comprising:

another photo-detector having a preferential spectral response to the incident light beam; and

a differential amplifier in connection to the photo-detectors to differentiate the detections of the photo-detectors and amplifies a difference between the detections.

48. The projector of claim 40 , further comprising:

another photo-detector;

wherein the incident light comprises a first and second component of different frequencies, the first and second components sequentially impinging the micromirror array;

wherein the photo-detector has a preferential spectral response to the first component of the incident light and generating a first timing signal corresponding to an arrival of the first component; and

wherein said another photo-detector has a preferential spectral response to the second component of the incident light generating a second timing signal corresponding to an arrival of the second component.

49. The projector of claim 48 , wherein the first timing signal and the second timing signal co-exist for a particular time period.