Light emitting diode projection display systems

• US 7,431,463 B2
• Filed: 10/05/2005
• Issued: 10/07/2008
• Est. Priority Date: 03/30/2004
• Status: Expired due to Fees

• Current Assignee: Goldeneye, Inc.
• Original Assignee: Goldeneye, Inc.
• Inventors: Beeson, Karl W., Zimmerman, Scott M.
• Primary Examiner(s): KOVAL, MELISSA J
• Application Number:
  US11/244,352
• Publication Number:
  US 20070206164A1
• Time in Patent Office: 1,098 Days
• Field of Search: 353/30, 353/31, 353/94, 353/98, 353/99, 353/121, 349/38, 313/113, 313/114, 359/853, 359/850, 362/308, 362/297, 362/347, 362/298, 348/742
• US Class Current: 353/94
• CPC Class Codes: G03B 21/2033 LED or laser light sources
• CPC Class Codes: G03B 21/2073 Polarisers in the lamp house peculiar to electronic spatial light modulators H04N9/3197
• CPC Class Codes: G03B 21/208 Homogenising, shaping of the illumination light
• CPC Class Codes: G03B 21/28 Reflectors in projection beam in illumination beam G03B21/2066
• CPC Class Codes: G03B 33/06 by additive-colour projection apparatus

Abstract

A projection display system has at least one light-recycling illumination system and at least one imaging light modulator. The light-recycling illumination system includes a light source that is enclosed within a light-recycling cavity. The light source is a plurality of light-emitting diode that emits light, and a fraction of that light will exit the light-recycling cavity through an aperture. The light-recycling cavity recycles a portion of the light emitted by the light source back to the light source in order to enhance the luminance of the light exiting the aperture. The fraction of the light that exits the aperture is partially collimated and is directed to the imaging light modulator. The imaging light modulator spatially modulates the partially collimated light to form an image.

Claims

1. A projection display system, comprising:

a light-recycling illumination system, wherein said light-recycling illumination system further comprises;

a plurality of light-emitting diodes, wherein each of said light-emitting diodes emits internally generated light, wherein each of said light-emitting diodes has a first reflecting electrode and a second reflecting electrode that reflect externally incident light, wherein each of said light-emitting diodes has a maximum intrinsic source luminance and wherein the total light-emitting area of said plurality of said light-emitting diodes is area A_LED;

a light-recycling cavity, wherein said plurality of said light-emitting diodes is disposed on the inside surfaces of said light-recycling cavity and wherein said light-recycling cavity and said first reflecting electrodes and said second reflecting electrodes of said light-emitting diodes reflect and recycle a portion of said internally generated light back to said light-emitting diodes as said externally incident light, thereby increasing the effective brightness of said light-emitting diodes; and

a light output aperture, wherein said light output aperture is located in a surface of said light-recycling cavity, wherein the area of said light output aperture is area A_O, wherein said area A_O is less than said area A_LED, wherein said light-emitting diodes and said light-recycling cavity direct at least a fraction of said internally generated light and said externally incident light out of said light-recycling cavity through said light output aperture and wherein said fraction of said internally generated light and said externally incident light exits said light output aperture as uncollimated light having a maximum exiting luminance;

a light-collimating means, wherein said light-collimating means has an input area that is adjacent to said light output aperture that accepts said uncollimated light, wherein said light-collimating means partially collimates

said uncollimated light and wherein said light-collimating means has an output

area through which the partially collimated light is transmitted; and

an imaging light modulator, wherein said imaging light modulator is located in the optical path of said partially collimated light, and wherein said imaging light modulator spatially modulates said partially collimated light to form an image.

2. A projection display system as in claim 1, further comprising a reflective polarizer, wherein said reflective polarizer is located in the optical path of said partially collimated light and is located adjacent to said output area of said light-collimating means, wherein said reflective polarizer reflects a first polarization state of said partially collimated light and wherein said reflective polarizer transmits a second polarization state of said partially collimated light.

3. A projection display system as in claim 1, wherein said maximum exiting luminance is greater than said maximum intrinsic source luminance.

4. A projection display system as in claim 3, further comprising a projection lens, wherein said projection lens is located in the optical path in a position after said imaging light modulator and wherein said projection lens magnifies said image formed by said imaging light modulator.

5. A projection display system as in claim 4, wherein said light-collimating means is chosen from the group consisting of a convex lens, a tapered light guide and a compound parabolic reflector.

6. A projection display system as in claim 5, wherein said imaging light modulator is chosen from the group consisting of a liquid crystal display device, a liquid-crystal-on-silicon device and a digital light processor device.

7. A projection display system as in claim 6, wherein said plurality of said light-emitting diodes emits red light, green light or blue light.

8. A projection display system as in claim 6, wherein said plurality of light-emitting diodes so emits white, yellow, cyan or magenta light.

9. A projection display system as in claim 6, wherein said plurality of light-emitting diodes emits ultraviolet light and wherein said light-recycling illumination system includes a wavelength conversion layer that converts said ultraviolet light into said red light or said green light or said blue light.

10. A projection display system as in claim 6, wherein said light-recycling cavity is filled or partially filled with a transparent material having an effective refractive index greater than 1.60.

11. A projection display system as in claim 7, further comprising a control unit, wherein said control unit manages the timing sequence for the emission of said red light, said green light or said blue light by a color sequential means.

12. A projection display system as in claim 11, wherein said light-recycling illumination system emits red light and wherein said projection display system further comprises a second light-recycling illumination system that emits green light and a third light-recycling illumination system that emits blue light.

13. A projection display system as in claim 12, further comprising a control unit, wherein said control unit manages the timing sequence for the emission of said red light, said green light or said blue light by a color sequential means.

14. A projection display system as in claim 13, wherein said projection display system further comprises a color combining means.

15. A projection display system as in claim 14, wherein said color combining means is chosen from the group of a trichroic prism and an x-cube prism.

16. A projection display system as in claim 15, wherein said control unit dynamically regulates the output brightness of said projection display system.

17. A projection display system as in claim 15, wherein said control unit regulates the output color temperature of said projection display system.

18. A projection display system as in claim 15, wherein said projection display system further comprises a second imaging light modulator and a third imaging light modulator.

19. A color sequential method of forming a full-color projection display image comprising the steps of:

dividing the time period for each frame of said full-color projection display image into at least a first sub-frame, a second sub-frame after said first sub-frame, and a third sub-frame after said second sub-frame;

during said first sub-frame, addressing all pixels of an imaging light modulator to set the transmission of said imaging light modulator for light of a first color, emitting said light of said first color from a first plurality of light-emitting diodes that each have a first reflecting electrode and a second reflecting electrode, recycling a portion of said light of said first color back to said first reflecting electrodes and said second reflecting electrodes to increase the effective brightness of said first plurality of said light-emitting diodes, partially collimating a fraction of said light of a first color, directing the partially collimated said light of said first color to said imaging light modulator and spatially modulating said partially collimated said light of said first color to form a first image;

during said second sub-frame, addressing all said pixels of said imaging light modulator to set said transmission of said imaging light modulator for light of a second color, emitting said light of a second color from a second plurality of said light-emitting diodes that each have said first reflecting electrodes and said second reflecting electrodes, recycling a portion of said light of said second color back to said first reflecting electrodes and said second reflecting electrodes to increase the effective brightness of said second plurality of said light-emitting diodes, partially collimating a fraction of said light of said second color, directing the partially collimated said light of said second color to said imaging light modulator and spatially modulating said partially collimated said light of said second color to form a second image; and

during said third sub-frame, addressing all said pixels of said imaging light modulator to set said transmission of said imaging light modulator for light of a third color, emitting said light of said third color from a third plurality of said light-emitting diodes that each have said first reflecting electrodes and said second reflecting electrodes, recycling a portion of said light of said third color back to said first reflecting electrodes and said second reflecting electrodes increase the effective brightness of said third plurality of light-emitting diodes, partially collimating a fraction of said light of said third color, directing the partially collimated said light of said third color to said imaging light modulator and spatially modulating said partially collimated said light of a third color to form a third image.

20. A projection display system as in claim 19, wherein said light of said first color is red light, said light of said second color is green light and said light of said third color is blue light.

21. A projection display system as in claim 20, further comprising a control unit, wherein said control unit manages the timing sequence for the emission of said red light, said green light or said blue light by a color sequential means.

22. A projection display system as in claim 21, wherein said control unit dynamically regulates the output brightness of said projection display system.

23. A method as in claim 22, further comprising:

regulating the output brightness of said projection display system by changing each of said red light output from said first plurality of light-emitting diodes, said green light output from said second plurality of light-emitting diodes and said blue light output from said third plurality of said light-emitting diodes by the same numerical factor.

24. A method as in claim 22, further comprising:

regulating the output brightness of said projection display system by changing each of the red light emitting time, the green light emitting time and the blue light emitting time by the same numerical factor.

25. A projection display system as in claim 21, wherein said control unit regulates the output color temperature of said projection display system.

26. A method as in claim 25, further comprising:

modifying the color temperature of said projection display system by changing the ratio of the red light output to the green light output to the blue light output.

27. A method as in claim 25, further comprising:

modifying the color temperature of said projection display system by changing the ratio of the red light emitting time to the green light emitting time to said blue light emitting time.

28. A method as in claim 21, further comprising:

emitting said red light, said green light and said blue light in random order in said first sub-frame, said second sub-frame and said third sub-frame.

29. A method as in claim 21, further comprising:

dividing the time period for each said frame into a fourth sub-frame after said third sub-frame and, during said fourth sub-frame, addressing all said pixels of said imaging light modulator to set said transmission of said imaging light modulator for light of a fourth color, emitting said light of said fourth color from a fourth plurality of said light-emitting diodes that each have said first reflecting electrodes and said second reflecting electrodes, recycling a portion of said light of said fourth color back to said first reflecting electrodes and said second reflecting electrodes to increase said effective brightness of said fourth plurality of said light-emitting diodes, partially collimating said light of said fourth color, directing the partially collimated said light of said fourth color to said imaging light modulator and spatially modulating said partially collimated said light of said fourth color to form a fourth image.