Full-color projection display system using two light modulators

• US 5,612,753 A
• Filed: 01/27/1995
• Issued: 03/18/1997
• Est. Priority Date: 01/27/1995
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Florence, James M., Poradish, Frank
• Primary Examiner(s): Lee, Michael
• Application Number:
  US08/379,391
• Time in Patent Office: 781 Days
• Field of Search: 348/744, 348/750, 348/771, 348/770, 348/756, 348/779, 348/781, 348/766, 348/755, 348/761, 348/782, 348/52, 348/51, 348/54, 348/60, 348/743, 348/742, 359/443, 359/448, 345/85, 345/32
• US Class Current: 348/743
• CPC Class Codes: G03B 21/2013 Plural light sources
• 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 9/3108 by using a single electronic spatial light modulator

Abstract

A full color projection system is disclosed herein. The projection system includes a means for generating a first light beam and also a means for generating a second light beam. These means may include either separate light sources 10a and 10b or a single light source 10 and a means for dividing the light source into the first and second light beams. In two examples, the means for dividing may include either a dichroic color wheel 40 or a color splitting prism 52. The first light beam will be modulated by a first spatial light modulator 30a and the second light beam will be modulated by a second spatial light modulator 30b. These spatial light modulators 30a and 30b are preferably, but not in necessarily digital micromirror devices.

Claims

1. A full-color projection system comprising:

a first light source for generating a first light beam;

a second light source for generating a second light beam;

a first spatial light modulator for receiving said first light beam and redirecting a modulated version of said first light beam to a screen;

a color wheel disposed between said first light source and said first spatial light modulator; and

a second spatial light modulator for receiving said second light beam and redirecting a modulated version of said second light beam to said screen.

2. The system of claim 1 wherein:

said means for generating a first light beam comprises a first lamp; and

said means for generating a second light beam comprises a second lamp.

3. The system of claim 1 wherein said first light source for generating a first light beam and said second light source for generating a second light beam comprise:

a single light source which generates a single beam of light; and

a light divider for dividing said single beam of light into said first and second light beams.

4. The system of claim 3 wherein said light divider comprises said color wheel.

5. The system of claim 3 wherein said light divider comprises a color splitting prism.

6. The system of claim 4 wherein said color wheel comprises a dichroic color wheel.

7. The system of claim 1 wherein said first and second spatial light modulators each comprise an array of individually controlled pixels.

8. The system of claim 7 wherein said first and second spatial light modulators comprise digital micro-mirror devices.

9. The system of claim 6 wherein each of said spatial light modulator comprises:

a plurality of pixels, each of said pixels including a deflectable beam, an address electrode adjacent said beam, and a landing electrode adjacent said beam;

wherein a voltage applied between said beam and said address electrode deflects said beam toward said address electrode, and said landing electrode is located to contact said beam deflected toward said address electrode and prevent said deflected beam from contacting said address electrode.

10. The system of claim 8 wherein each of said spatial light modulator comprises:

a plurality of pixels formed in a layered structure;

said layered structure including an insulated substrate, a spacer layer on said substrate, a conductive reflecting layer on said spacer layer, and a plurality of addressing and landing electrodes;

each of said pixels including

a deflectable element formed in said reflecting layer and connected to the remainder of said reflecting layer by at least one hinge formed from said reflecting layer,

a well formed in said spacer layer and extending from said deflectable element to said substrate,

a first addressing electrode on said substrate at the bottom of said well and located to deflect said deflectable element by electrostatic attraction, and

a first landing electrode on said substrate at the bottom of said well,

said first landing electrode located both to contact said deflectable element when said deflectable element is deflected by attraction by said first addressing electrode to said substrate and to prevent said deflectable element from contacting said addressing electrode.

11. A full-color projection system comprising:

a first light source for generating a first beam of light;

a first color wheel for receiving said first beam of light and transmitting a filtered version of said first beam of light;

a first spatial light modulator for receiving said filtered version of said first beam of light and directing a modulated version of said first beam of light to a screen;

a second light source for generating a second beam of light;

a second color wheel for receiving said second beam of light and transmitting a filtered version of said second beam of light; and

a second spatial light modulator for receiving said filtered version of said second beam of light and directing a modulated version of said second beam of light to said screen.

12. A full-color projection display system comprising:

a light source for generating a light beam;

a color wheel for receiving said light beam, said color wheel transmitting a first light beam and reflecting a second light beam;

a first spatial light modulator for receiving said first light beam and directing a modulated version of said first beam of light to a screen;

a reflector for receiving and redirecting said second light beam; and

a second spatial light modulator for receiving said second light beam and directing a modulated version of said second beam of light to said screen.

13. The system of claim 12 wherein said reflector is positioned so as to direct said second light beam through said color wheel before said second light beam reaches said spatial light modulator.

14. The system of claim 12 wherein said color wheel transmits a first light beam comprising of a primary color and reflects a second light beam comprising of a complimentary color.

15. The system of claim 12 wherein said first and second spatial light modulators comprise digital micro-mirror devices.

16. A full color projection system comprising:

a light source for generating a beam of light;

a color wheel for receiving said beam of light and passing a filtered light beam;

a color splitting prism for directing a first portion of said filtered light beam to a first spatial light modulator and a second portion of said filtered light beam to a second spatial light modulator; and

a screen for receiving modulated light from both said first and second spatial light modulators.

17. The system of claim 16 wherein said color wheel passes light of one of the primary colors all the time and light of the other primary colors half of the time, wherein the primary colors consist of red, green and blue.

18. The system of claim 17 wherein said color wheel comprises first and second segments, said first segment for passing magenta colored light and said second segment for passing yellow colored light.

19. The system of claim 16 and further comprising a total internal reflection prism positioned between said color splitting prism and said screen.

20. A method of illuminating a region, said method comprising the steps of:

generating a first light beam;

modulating said first light beam;

generating a second light beam;

filtering said second light beam such that said second light beam is a first color during a first time period and a second color during a second time period;

modulating said filtered second light beam;

directing said first light beam to said region; and

directing light from said filtered second light beam to said region.

21. The method of claim 20 wherein said steps of generating first and second light beams comprise generating a first light beam which includes red, blue and green components and generating a second light beam which also includes red, blue and green components.

22. The method of claim 20 wherein said step of generating a first light beam comprises the step of generating a light beam which includes components of some but not all of said primary colors.

23. The method of claim 20 wherein said step of directing said first light beam comprises directing a light beam of a first color and said step of directing said second light beam comprises directing a light beam of a second color, wherein said first color is different than said second color.

24. The method of claim 22 wherein said first light beam and said second light beam have offset color fields.

25. The method of claim 23 wherein said first light beam comprises light comprised primarily of only one of the primary colors.

26. The method of claim 25 wherein said second light beam comprises light comprised primarily of the other primary colors.

27. A full color projection system comprising:

a first light beam generating apparatus;

a first spatial light modulator for receiving a first light beam from said first light beam generating apparatus and directing a modulated version of said first light beam to a region to be illuminated;

a second light beam generating apparatus;

a light color filter disposed to receive a second beam of light from said second light beam generator, said light color filter filtering said second light beam such that the second light beam is a first color during a first time period and a second color during a second time period; and

a second spatial light modulator for receiving said filtered second light beam from said second light beam generating apparatus and redirecting a modulated version of said filtered second light beam to a region to be illuminated.

28. The system of claim 27 wherein said first light beam generating apparatus comprises a first lamp and said second light beam generating apparatus comprises a second lamp.

29. The system of claim 27 wherein said first and second light beam generating apparatus each utilize a single light source.

30. The system of claim 29 wherein said first and second light beam generating apparatus further comprise a light splitting apparatus to divide light from said single light source into said first and second light beams.

31. The system of claim 29 wherein said light splitting apparatus comprises a dichroic color wheel.

32. The system of claim 30 wherein said light splitting apparatus comprises a prism.