System and method for aligning RGB light in a single modulator projector

• US 7,891,818 B2
• Filed: 12/12/2007
• Issued: 02/22/2011
• Est. Priority Date: 12/12/2006
• Status: Expired due to Fees

• Current Assignee: Evans & Sutherland Computer Corp. (Elevate Entertainment, Inc.)
• Original Assignee: Evans & Sutherland Computer Corp. (Elevate Entertainment, Inc.)
• Inventors: Elkins, Dennis, Tanner, Allen H., Christensen, Robert R., Winkler, Bret D.
• Primary Examiner(s): Epps; Georgia Y
• Assistant Examiner(s): CHOWDHURY, SULTAN U.
• Application Number:
  US12/001,771
• Publication Number:
  US 20080212035A1
• Time in Patent Office: 1,168 Days
• Field of Search: 353/31, 353/94, 353/84, 353/76, 353/122, 372/25, 372/28, 372/29.02, 372/6, 372/30, 348/742, 348/743, 348/771, 348/754, 348/769, 348/E5.139, 348/311, 359/290, 359/291, 359/238, 359/276, 359/278
• US Class Current: 353/31
• CPC Class Codes: G03B 21/005 Projectors using an electronic spatial light modulator but not peculiar thereto
• CPC Class Codes: G03B 21/20 Lamp housings
• CPC Class Codes: G03B 27/547 colour mixing heads
• CPC Class Codes: G03B 33/06 by additive-colour projection apparatus
• CPC Class Codes: G03B 33/08 Sequential recording or projection G03B33/02, G03B33/04, G03B33/06 take precedence
• 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 9/3164 using multiple light sources

Abstract

A projection system that includes a singe light modulation device and a plurality of light sources of different wavelengths. Each wavelength of light is incident on the light modulation device at a spatially distinct location and a temporally distinct time. The use of a scanning mirror allows the projection system to sequentially form, in full-color, each of the columns or rows of an image. The projection system is characterized by the reduction of color separation or the rainbow effect due to the rendering of each column or row in full color.

Claims

1. A projection system for generating an image on a surface, the projection system comprising:

a light modulation device;

a plurality of light sources, each of the plurality of light sources emitting a different wavelength of light that is imaged on the light modulation device as a column of light having a height, a width, and a centerline bisecting the column of light along its height;

an input optical assembly interposed between said light modulation device and the plurality of light sources; and

wherein each of centerlines of the columns of light is centered on the light modulation device at a spatially distinct location with respect to the centerlines of the other columns of light;

wherein a spacing between adjacent centerlines of columns of light on the light modulation device is at least 1.5 microns;

wherein each column of light has a substantially uniform distribution along its height and a non-uniform distribution along its width.

2. The projection system of claim 1, wherein said light modulation device is operable between a first configuration and a second configuration, wherein said first configuration acts to reflect incident light as a plane mirror and said second configuration acts to diffract incident light.

3. The projection system of claim 1, wherein the light modulation device comprises a plurality of elongated ribbons, each of the plurality of elongated ribbons having a light reflective surface.

4. The projection system of claim 1, wherein said plurality of light sources comprises a red light source, a green light source and a blue light source.

5. The projection system of claim 1, wherein each of the plurality of light sources is a laser.

6. The projection system of claim 1, further comprising a scanning mirror for scanning modulated light.

7. The projection system of claim 1, further comprising a projection lens.

8. The projection system of claim 1, wherein the image comprises a plurality of linear elements, and wherein the light modulation device modulates the different wavelengths of light to thereby sequentially form, in full color, each of the linear elements of the image on a reflective surface.

9. The projection system of claim 8, wherein said linear elements comprise at least one of columns and rows of the image.

10. The projection system of claim 1, wherein the plurality of light sources pulses each of the different wavelengths of light at a temporally distinct time.

11. The projection system of claim 1, further comprising a filter for separating a diffracted portion of light from a non-diffracted portion of light.

12. The projection system of claim 1, wherein the plurality of light sources emits each of the wavelengths of light in pulses having a pulse duration.

13. The projection system of claim 12, wherein the pulse duration of each of the wavelengths of light is variable.

14. The projection system of claim 12, wherein the pulse duration is determined as a function of a resolution of a projector.

15. The projection system of claim 12, wherein the pulse duration is about 0.5 microseconds.

16. The projection system of claim 1, further comprising a lens having a focal point, said lens operable to focus the wavelengths of light, wherein a modulating surface of the light modulator is located disjunct from the focal point of the lens such that the wavelengths of light are slightly unfocused on the modulating surface.

17. The projection system of claim 1, wherein the image comprises a plurality of pixels, each of the pixels having a pixel height;

and wherein spacing between the centerlines of adjacent columns of light is determined as a function of the pixel height.

18. The projection system of claim 1, wherein the spacing between adjacent centerlines of columns of light on the light modulation device is at least 2.0 microns.

19. The projection system of claim 1, wherein the spacing between adjacent centerlines of columns of light on the light modulation device is between 2.3 microns and 2.7 microns.

20. A projection system for generating an image on a surface, the image comprising a plurality of linear elements, the projection system comprising:

a light modulation device;

a scan mirror;

a plurality of light sources, each of the plurality of light sources emitting a different wavelength, or range of wavelengths, of light that is incident on the light modulation device; and

wherein the light modulation device modulates the light incident thereon to thereby sequentially form, in full color, each of the plurality of linear elements of the image on the surface during a single sweep of the scan mirror.

21. The projection system of claim 20, wherein said light modulation device is operable between a first configuration and a second configuration, wherein said first configuration acts to reflect incident light as a plane mirror and said second configuration acts to diffract incident light.

22. The projection system of claim 20, wherein the light modulation device comprises a plurality of elongated ribbons, each of the plurality of ribbons having a light reflective surface.

23. The projection system of claim 20, wherein said plurality of light sources comprises a red light source, a green light source, and a blue light source.

24. The projection system of claim 20, wherein each of the plurality of light sources is a laser.

25. The projection system of claim 20, further comprising a projection lens.

26. The projection system of claim 20, wherein said plurality of linear elements comprise at least one of columns and rows of the image.

27. The projection system of claim 20, wherein the light from each of the plurality of light sources is centered on the light modulation device at a spatially distinct location.

28. The projection system of claim 20, wherein each of said plurality of light sources pulses light at a temporally distinct time.

29. The projection system of claim 20, further comprising a filter for separating a diffracted portion of light from a non-diffracted portion of light.

30. A projection system comprising:

a scanning mirror;

a plurality of light sources, each of the plurality of light sources emitting a different wavelength, or range of wavelengths, of light that is incident on the scanning mirror after being modulated; and

wherein each of the different wavelengths, or range of wavelengths, of light is centered on the scanning mirror at a location that is spatially distinct.

31. The projection system of claim 30, wherein each of the different wavelengths, or range of wavelengths, of light is incident on the scanning mirror at a temporally distinct time.

32. The projection system of claim 30, further comprising a light modulation device, said light modulation device disposed in an optical path between the plurality of light sources and the scanning mirror.

33. The projection system of claim 32, wherein said light modulation device is operable between a first configuration and a second configuration, wherein said first configuration acts to reflect incident light as a plane mirror and said second configuration acts to diffract incident light.

34. The optical device of claim 32, wherein the light modulation device comprises a plurality of ribbons, each of the plurality of ribbons having a light reflective surface.

35. The optical device of claim 30, wherein modulated light scanned by the scanning mirror sequentially forms, in full color, a plurality of linear elements of an image on a surface.

36. The optical device of claim 35, wherein said linear elements comprises at least one of columns and rows of the image.

37. A method for forming an image on a surface, the image comprising a plurality of linear elements, the method comprising the step of sequentially forming, in full color, each of the linear elements of the image on the surface using a single light modulation device during a single sweep of a scan mirror.

38. The method of claim 37, further comprising the step of pulsing each of a plurality of different wavelengths of light onto the single light modulation device at a temporally distinct time.

39. The method of claim 38, further comprising the step of centering the different wavelengths of light onto spatially distinct locations of the single light modulation device.

40. The method of claim 37, wherein said single light modulation device is operable between a first configuration and a second configuration, wherein said first configuration acts to reflect incident wavelengths of light as a plane mirror and said second configuration acts to diffract incident wavelengths of light.

41. The method of claim 37, wherein said linear elements comprises at least one of columns and rows of the image.

42. The method of claim 37, further comprising the step of scanning modulated wavelengths of light with a scanning mirror.

43. The method of claim 37, further comprising the step of separating a diffracted portion of light from a non-diffracted portion of light.