Color sequential illumination system for a liquid crystal light valve

• US 4,786,146 A
• Filed: 02/11/1987
• Issued: 11/22/1988
• Est. Priority Date: 02/11/1987
• Status: Expired due to Term

• Current Assignee: Victor Company of Japan Limited (JVC Kenwood Corporation)
• Original Assignee: Hughes Aircraft Company (Rtx Corporation)
• Inventors: Ledebuhr, Arno G.
• Primary Examiner(s): Miller, Stanley D.
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US07/013,307
• Time in Patent Office: 650 Days
• Field of Search: 350/337, 350/331 R, 350/342, 350/339 F, 350/401, 350/402, 350/404, 350/408, 350/387-389, 350/173, 350/174, 353/31, 353/33, 353/37, 353/20, 358/225, 358/226, 358/232, 358/237
• US Class Current: 349/9
• CPC Class Codes: G02B 27/1033 having a single light modulator for all colour channels
• CPC Class Codes: G02B 27/145 having sequential partially reflecting surfaces
• CPC Class Codes: G02F 1/133621 providing coloured light G02F1/133617, G02F1/133533 take precedence
• CPC Class Codes: G02F 1/133622 Colour sequential illumination
• CPC Class Codes: H04N 9/3114 by using a sequential colour filter producing one colour at a time
• CPC Class Codes: H04N 9/3167 for polarizing the light beam polarizing optical systems per se G02B27/28

Abstract

A color sequential illumination system for a liquid crystal light valve is disclosed. The invention operates with no moving parts and provides for the sequential illumination of a light valve with at least two beams of different colors. The rate is fast enough that the colors fuse together and the viewer sees a composite color image. The system includes a prepolarizer and dichroics for providing a first beam along a first optical path having a first color and a first polarization state and a second beam along a second optical path having a second color and said first polarization state. An optical switch is provided for selectively transmitting the first and second beams by sequentially changing the polarization state of each. Associated optical components are provided for directing the first and second beams onto the liquid crystal light valve.

Claims

1. A color sequential system for illuminating a liquid crystal light valve with a first beam having a first color and a first polarization state and second beam having a second color and said first polarization state, said system comprising:

first means for providing a first beam along a first optical path having a first color and said first polarization state;

second means for providing a second beam along a second optical path having a second color and said first polarization state;

optical switch means for selectively transmitting said first and second beams by changing the polarization state thereof;

third means for directing said first beam onto said liquid crystal light valve and

fourth means for directing said second beam onto said liquid crystal light valve.

2. The color sequential system of claim 1 wherein said optical switch means includes first and second polarization switches.

3. The color sequential system of claim 2 including control means for selectively and sequentially activating said first and second polarization switches.

4. The color sequential system of claim 3 wherein said first and second means includes a prepolarizer.

5. The color sequential system of claim 4 wherein said first means further includes a first color filter.

6. The color sequential system of claim 5 wherein said second means includes a second color filter.

7. The color sequential system of claim 5 wherein said second means includes a reflector.

8. The color sequential system of claim 3 wherein said third means includes a third color filter.

9. The color sequential system of claim 3 wherein said third means includes a reflector.

10. The color sequential system of claim 3 wherein said fourth means includes a fourth color filter.

11. A color sequential system for illuminating a full color liquid crystal light valve with a first beam having a first color and a first polarization state and second beam having a second color and said first polarization state, said system comprising:

first means for providing a first beam along a first optical path;

second means for providing a second beam along a second optical path;

first and second polarization switch means for selectively and sequentially transmitting said first and second beams respectively;

control means for selectively and sequentially activating said first and second polarization switch means;

third means for directing said first beam onto said liquid crystal light valve and

fourth means for directing said second beam onto said liquid crystal light valve.

12. The color sequential system of claim 11 wherein said first and second means includes a prepolarizer.

13. The color sequential system of claim 12 wherein said first means further includes a first color filter.

14. The color sequential system of claim 13 wherein said second means includes a second color filter.

15. The color sequential system of claim 13 wherein said second means includes a reflector.

16. The color sequential system of claim 11 wherein said third means includes a third color filter.

17. The color sequential system of claim 11 wherein said third means includes a reflector.

18. The color sequential system of claim 11 wherein said fourth means includes a fourth color filter.

19. The color sequential system of claim 11 wherein said polarization switches provide means for selectively changing the polarization state of said first and second beams.

20. A color sequential method for illuminating a full color liquid crystal light valve with a first beam having a first color and a first polarization state and second beam having a second color and said first polarization state, said method including the steps of:

(a) providing a first beam along a first optical path;

(b) providing a second beam along a second optical path;

(c) selectively and sequentially changing the polarization state of said first and second beams;

(d) directing said first beam onto said liquid crystal light valve and

(e) directing said second beam onto said liquid crystal light valve