Rod integrators for light recycling

• US 20010008470A1
• Filed: 12/28/2000
• Published: 07/19/2001
• Est. Priority Date: 12/30/1999
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Dewald, Duane Scott
• Granted Patent: US 7,052,150 B2
• Time in Patent Office: Days
• US Class Current: 359/850
• CPC Class Codes: G02B 26/008 in the form of devices for effecting sequential colour changes, e.g. colour wheels
• CPC Class Codes: G02B 27/0927 Systems for changing the beam intensity distribution, e.g. Gaussian to top-hat
• CPC Class Codes: G02B 27/0994 Fibers, light pipes optical fibers per se G02B6/02
• CPC Class Codes: G02B 27/283 used for beam splitting or combining
• CPC Class Codes: G02B 27/286 for controlling or changing the state of polarisation, e.g. transforming one polarisation state into another G02B5/3083 takes precedence; light guide coupling means utilising polarising elements G02B6/34
• CPC Class Codes: G02B 6/29361 Interference filters, e.g. multilayer coatings, thin film filters, dichroic splitters or mirrors based on multilayers, WDM filters
• CPC Class Codes: G02B 6/29395 configurable, e.g. tunable or reconfigurable switching G02B6/35
• CPC Class Codes: G02B 6/4298 coupling with non-coherent light sources and/or radiation detectors, e.g. lamps, incandescent bulbs, scintillation chambers
• CPC Class Codes: G02F 1/13362 providing polarized light, e.g. by converting a polarisation component into another one
• CPC Class Codes: G02F 1/133622 Colour sequential illumination
• CPC Class Codes: H04N 9/3117 by using a sequential colour filter producing two or more colours simultaneously, e.g. by creating scrolling colour bands
• CPC Class Codes: H04N 9/3152 for shaping the light beam beam shaping per se G02B27/09
• CPC Class Codes: H04N 9/3167 for polarizing the light beam polarizing optical systems per se G02B27/28
• CPC Class Codes: Y10S 385/901 Illuminating or display apparatus

Abstract

An integrating rod (200) for use with a multiple segment dynamic filter, such as a spiral dichroic color wheel having three or more narrow filters adjacent to the exit face (206) to enable the integrating rod to recapture light rejected by a given segment of the dynamic filter. The rejected light travels back through the integrating rod where a majority of the light strikes the mirrored entrance face (202). Light reflected by the mirrored entrance face, or light exiting through the entrance aperture (204) and returning to the integrating rod after being reflected by the lamp reflector, once again travels to the exit face (206) of the integrating rod (200). After exiting through the exit face (206) of the integrating rod (200) a second time, the recycled light has a good chance of striking a different filter segment of the dynamic filter and being used by the display system.

Claims

1. An integrating rod comprised of:

an elongated body, said elongated body operable to reflect light traveling through said elongated body;

an entrance face on a first end of said elongated body; and

a mirrored entrance aperture at said entrance face, said mirrored entrance aperture having a transmissive entrance aperture portion and a mirrored portion, said mirrored entrance aperture allowing light to pass through the aperture thereof to enter the elongated body of said integrating rod, said mirrored entrance aperture operable to reflect light traveling through said elongated body to said entrance face that strikes said mirrored entrance aperture outside said transmissive entrance aperture.

2. The integrating rod of

claim 1

, wherein said entrance aperture is circular.

3. The integrating rod of

claim 1

, wherein said entrance aperture is elliptical.

4. The integrating rod of

claim 1

, wherein said entrance aperture is rectangular.

5. The integrating rod of

claim 1

, wherein said entrance aperture is centered on said entrance face and surrounded by said mirrored portion of said mirrored entrance aperture.

6. The integrating rod of

claim 1

, wherein said mirrored entrance aperture is on said entrance face.

7. The integrating rod of

claim 1

, wherein said mirrored entrance aperture is a metal layer deposited on said entrance face.

8. The integrating rod of

claim 1

, wherein said mirrored entrance aperture is a mirror positioned next to said entrance face.

9. The integrating rod of

claim 1

, said elongated body having a circular cross section.

10. The integrating rod of

claim 1

, said elongated body having a rectangular cross section.

11. The integrating rod of

claim 1

, said elongated body having a triangular cross section.

12. The integrating rod of

claim 1

, said elongated body having a hexagonal cross section.

13. The integrating rod of

claim 1

, said elongated body having a square cross section.

14. The integrating rod of

claim 1

, wherein said elongated body is tapered.

15. The integrating rod of

claim 1

, wherein said elongated body is hollow.

16. The integrating rod of

claim 1

, wherein said elongated body is a solid transparent body.

17. The integrating rod of

claim 1

, wherein said elongated body is glass.

18. The integrating rod of

claim 1

, wherein said light traveling through said elongated body is reflected by mirrored surfaces along said elongated body.

19. The integrating rod of

claim 1

, wherein said light traveling through said elongated body is reflected by total internal reflection at an interface between said elongated body and a media surrounding said elongated body.

20. The integrating rod of

claim 19

, wherein said media surrounding said elongated body is air.

21. The integrating rod of

claim 1

, further comprising a mirrored exit aperture at an exit face of said elongated body, said mirrored exit aperture having a transmissive exit aperture portion and a mirrored exit portion, said mirrored exit aperture allowing light to pass through the aperture thereof after leaving said elongated body of said integrating rod, said mirrored exit aperture operable to reflect light traveling through said elongated body to said exit face that strikes said mirrored exit aperture outside said transmissive exit aperture.

22. The integrating rod of

claim 21

, wherein said exit face is opposite said entrance face.

23. The integrating rod of

claim 21

, wherein said exit aperture is circular.

24. The integrating rod of

claim 21

, wherein said exit aperture is elliptical.

25. The integrating rod of

claim 21

, wherein said exit aperture is rectangular.

26. The integrating rod of

claim 21

, wherein said exit aperture is centered on said exit face and surrounded by said mirrored portion of said mirrored exit aperture.

27. The integrating rod of

claim 21

, wherein said mirrored exit aperture is on said exit face.

28. The integrating rod of

claim 21

, wherein said mirrored exit aperture is a metal layer deposited on said exit face.

29. The integrating rod of

claim 21

, wherein said mirrored exit aperture is a mirror positioned next to said exit face.

30. A polarizing integrating rod comprised of:

an elongated body, said elongated body operable to reflect light traveling through said elongated body;

an entrance face on a first end of said elongated body;

a mirrored entrance aperture at said entrance face, said mirrored entrance aperture having a transmissive entrance aperture portion and a mirrored portion, said mirrored entrance aperture allowing light to pass through the aperture thereof to enter the elongated body of said integrating rod, said mirrored entrance aperture operable to reflect light traveling through said elongated body to said entrance face that strikes said mirrored entrance aperture outside said transmissive entrance aperture;

a polarizing coating, said polarizing coating transmitting light of a first polarization and reflection light of a second polarization;

a quarter wave plate for receiving light of said second polarization reflected by said polarizing coating and converting said light of a second polarization to said first polarization.