Polarization recapture system for liquid crystal-based data projectors

• US 6,739,723 B1
• Filed: 12/07/2001
• Issued: 05/25/2004
• Est. Priority Date: 12/07/2001
• Status: Active Grant

• Current Assignee: Delta Electronics Incorporated
• Original Assignee: Delta Electronics Incorporated
• Inventors: Haven, Thomas J., Munson, Kurt R.
• Primary Examiner(s): Adams, Russell
• Assistant Examiner(s): Koval, Melissa J
• Application Number:
  US10/014,029
• Time in Patent Office: 900 Days
• Field of Search: 353/20, 353/33, 353/34, 353/37, 353/84, 353/121, 353/31, 353/97, 353/98, 353/102, 349/5, 349/7, 349/8, 349/9, 348/744, 348/758, 348/761, 348/790
• US Class Current: 353/20
• 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 9/315 Modulator illumination systems general applications of lighting devices F21V; general optical systems G02B; lamp houses for projectors not peculiar to the presence of an electronic spatial light modulator G03B21/20

Abstract

A projection display system includes a light source emitting a randomly polarized light and a polarization recapture system including a tunnel integrator and a transmitting/reflecting polarizer coupled to the output end of the tunnel integrator. The input end of the tunnel integrator includes an input aperture and a reflective inside surface coated with a quarter wave retarder. In operation, the randomly polarized light enters the tunnel integrator through the input aperture. The polarization recapture system transmits light having a first polarization as polarized light output and recycles light having a second polarization orthogonal to the first polarization. The light having the second polarization is reflected by the transmitting/reflecting polarizer back into the tunnel integrator. The polarization recapture system recycles the light having the second polarization by reflecting and reorienting the light having the second polarization to light of the first polarization.

Claims

1. A projection display system, comprising:

a light source emitting a randomly polarized light;

a tunnel integrator having an input end and an output end, the input end comprising and input aperture and a reflective inside surface coated with a quarter wave retarder, the randomly polarized light from the light source arriving at the input end of the tunnel integrator, entering the tunnel integrator through the input aperture, and outputting the tunnel integrator at the output end as uniform beam of light;

a plurality of dichroic filters coupled to the output end of the tunnel integrator, each of the plurality of dichroic filter disposed to transmit light of one of at least three primary color components; and

a four-sided prism coupled in the optical path of the tunnel integrator and the plurality of dichroic filter;

wherein the four-sided prism is rotated for scrolling colored light of in each of the at least three primary color components generated by the plurality of dichroic filters.

2. The projection display system of claim 1, further comprising:

a transmitting/reflecting polarizer coupled between the output end of the tunnel integrator and the plurality of dichroic filters, the transmitting/reflecting polarizer transmitting light having a first polarization as polarized light output and reflecting light having a second polarization orthogonal to the first polarization back into the tunnel integrator; and

an LCD panel for modulating the polarized and colored light output form the four-sided prism to form modulated light output indicative of an image to be displayed;

wherein the tunnel integrator recycles the light of the second polarization by reflecting and reorienting the light of the second polarization to light of the first polarization.

3. The projection display system of claim 1, wherein the plurality of dichroic filters are arranged as rectangular bands across the output end of the tunnel integrator.

4. A projection display system, comprising:

a light source emitting randomly polarized light;

a polarization recapture system comprising;

a tunnel integrator having an input end and an output end, the input end comprising an input aperture and a reflective inside surface coated with a quarter wave retarder; and

a transmitting/reflecting polarizer coupled to the output end of the tunnel integrator;

a relay lens assembly arranged in the optical path between the polarization recapture system and an LCD panel, the relay lens assembly collimating and focusing the polarized light output onto the LCD panel, wherein the relay lens assembly comprises a first positive relay lens of a strong curvature and a second positive relay lens of a weaker curvature;

the LCD panel modulating the polarized light output to form modulated light output indicative of an image to be displayed; and

a projection lens assembly arranged in the optical path of the LCD panel for projecting the modulated light output from the LCD panel,

wherein the randomly polarized light from the light source arrives as the input end of the tunnel integrator and enters the tunnel integrator through the input aperture, and the polarization recapture system transmits light having a first polarization as polarized light output and recycles light having a second polarization orthogonal to the first polarization.

5. The projection display system of claim 4, wherein the light having the second polarization is reflected by the transmitting/reflecting polarizer back into the tunnel integrator, and the polarization recapture system recycles the light having the second polarization by reflecting the light from the reflective inside surface and reorienting the light having the second polarization to light of the first polarization.

6. The projection display system of claim 4, wherein the reflective inside surface is a mirrored inside surface except at the input aperture.

7. The projection display system of claim 6, wherein the mirrored inside surface is an aluminum coated mirrored inside surface.

8. The projection display system of claim 4, wherein the input aperture is a circular transport area.

9. The projection display system of claim 4, wherein the input aperture has an area approximately equal to a one-third of the cross-sectional area of the input end of the tunnel integrator.

10. The projection display system of claim 4, wherein the quarter wave retarder comprises a quarter wave plate attached to the reflective inside surface at the input end of the tunnel integrator.

11. The projection display system of claim 10, wherein the quarter wave plate comprises a plastic, transparent laminate with an adhesive coating.

12. The projection display system of claim 10, wherein the quarter wave plate comprises a quartz wave plate.

13. The projection display system of claim 4, wherein the tunnel integrator is a rod-type solid glass light integrator.

14. The projection display system of claim 4, wherein the tunnel integrator is a rod-type high-reflectance light tunnel.

15. The projection display system of claim 14, wherein the tunnel integrator has a cross-sectional area of about 5 mm by 5 mm.

16. The projection display system of claim 14, wherein a cross-sectional area of the tunnel integrator has a width:

height ratio of 4;

3 or 16;

9.

17. The projection display system of claim 14, wherein the tunnel integrator has a length of approximately 25 to 30 mm.

18. The projection display system of claim 14, wherein the tunnel integrator has a length to height or width ratio of 5:

1.

19. The projection display system of claim 4, wherein the light source comprises a lamp emitting the randomly polarized light and an elliptical reflector directing the randomly polarized light at the input aperture of the tunnel integrator.

20. The projection display system of claim 4, wherein the light source comprises a lamp emitting the randomly polarized light, a parabolic reflector and a condenser lens directing the randomly polarized light at the input aperture of the tunnel integrator.

21. The projection display system of claim 4, wherein the transmitting/reflecting polarizer is a thin film reflective polarizer.

22. The projection display system of claim 4, wherein the transmitting/reflecting polarizer is a crystal-based reflective polarizer.

23. The projection display system of claim 4, wherein the transmitting/reflecting polarizer is a wire grid polarizer.

24. The projection display system of claim 23, wherein the wire grid polarizer is adhered to the output end of the tunnel integrator.

25. The projection display system of claim 23, wherein the wire grid polarizer comprises a transparent glass substrate and parallel metal lines formed thereon.

26. The projection display system of claim 25, wherein the wire grid polarizer transmits polarized light that is normal to the long axis of the metal lines and reflects polarized light that is parallel to the long axis of the metal lines.

27. The projection display system of claim 25, wherein the parallel metal lines are separated by a pitch that is less than one-half of the shortest wavelength of light to be polarized.

28. The projection display system of claim 4, wherein the transmitting/reflecting polarizer has an area equal to the cross-sectional area to the tunnel integrator.

29. The projection display system of claim 4, wherein the LCD panel comprises a liquid crystal module and control electrodes sandwiched between transparent glass plates, and an output polarizer.

30. The projection display system of claim 29, wherein the LCD panel further comprises a pattern of color filters superimposed and in registration with each pixel on the LCD module.

31. The projection display system of claim 30, wherein the pattern of color filters comprises color stripes in each of three primary colors.

32. The projection display system of claim 4, wherein the LCD panel further comprises an input polarizer.

33. The projection display system of claim 4, wherein the relay lens assembly is one of a plurality of relay lens assemblies and the LCD panel is one of a plurality of LCD panels, and the projection display system further comprises:

a plurality of color dichroic mirrors disposed in the optical path between the transmitting/reflecting polarizer and a respective one of the relay lens assemblies, each of the relay lens assemblies directing one color component of the polarizer light output to a respective one of the plurality of LCD panels; and

a color recombining prism in the optical path between the plurality of LCD panels and the project lens assembly for recombining modulated light output from each of the plurality of LCD panels to from a full color display image.

34. A projection display system, comprising:

a light source emitting randomly polarized light;

a polarization recapture system comprising;

a tunnel integrator having an input end and an output end, comprising an input aperture and a reflective inside surface coated with a quarter wave retarder; and

a transmitting/reflecting polarizer coupled to the output end of the tunnel integrator;

a relay lens assembly arranged in the optical path between the polarization recapture system and an LCD panel, the relay lens assembly collimating and focusing the polarized light output onto the LCD panel;

the LCD panel modulating the polarized light output to form modulated light output indicative of an image to be displayed;

a projection lens assembly arranged in the optical path of the LCD panel for projecting the modulated light output from the LCD panel; and

a color wheel in the optical path between the transmitting/reflecting polarizer and the relay lens assembly, the color wheel comprising at least three color components thereon representative of three primary colors,

wherein the randomly polarized light from the light source arrives as the input end of the tunnel integrator and enters the tunnel integrator through the input aperture, and the polarization recapture system transmits light having a first polarization as polarized light output and recycles light having a second polarization orthogonal to the first polarization.

35. The projection display system of claim 34, wherein the color wheel comprises color dichroic coating of the at least three color components arranged in a spiral pattern.

36. A projection display system, comprising:

a light source emitting randomly polarized light;

a polarization recapture system comprising;

a tunnel integrator having an input end and an output end and an output end, the input end comprising an input aperture and a reflective inside surface coated with a quarter wave retarder; and

a transmitting/reflecting polarizer coupled to the output end of the tunnel integrator;

a relay lens assembly arranged in the optical path between the polarization recapture system and an LCD panel, the relay lens assembly collimating and focusing the polarized light output onto the LCD panel;

the LCD panel modulating the polarized light output to form modulated light output indicative of an image to be displayed;

a projection lens assembly arranged in the optical path of the LCD panel for projecting the modulated light output from the LCD panel; and

a color wheel in the optical path between the relay lens assembly and the LCD panel, the color wheel comprising at least three color components thereon representative of three primary colors,

wherein the randomly polarized light from the light source arrives at the input end of the tunnel integrator and enters the tunnel integrator through the input aperture, and the polarization recapture system transmits light having a first polarization as polarized light output and recycles light having a second polarization orthogonal to the first polarization.

37. The projection display system of claim 36, wherein the color wheel comprises color dichroic coating of the at least three color components arranged in a spiral pattern.

38. A projection display system, comprising:

a light source emitting randomly polarized light;

a polarization recapture system comprising;

a tunnel integrator having an input end and an output end, the input end comprising an input aperture and a reflective inside surface coated with a quarter wave retarder; and

a transmitting/reflecting polarizer coupled to the output end of the tunnel integrator;

a relay lens assembly arranged in the optical path between the polarization recapture system and an LCD panel, the relay lens assembly collimating and focusing the polarized light output onto the LCD panel;

the LCD panel modulating the polarized light output to form modulated light output indicative of an image to be displayed;

a projection lens assembly arranged in the optical path of the LCD panel for projecting the modulated light output from the LCD panel;

a plurality of dichroic filters coupled to the transmitting/reflecting polarizer, each of the plurality of dichroic filters disposed to transmit light of one of at least three primary color components; and

a four-sided prism coupled between the relay lens assembly and the LCD panel, wherein the four-sided prism is rotated for scrolling light of each of the at least three primary color components across the LCD panel,

wherein the randomly polarized light from the light source arrives at the input end of the tunnel integrator and enters the tunnel integrator through the input aperture, and the polarization recapture system transmits light having a first polarization as polarized light output and recycles light having a second polarization orthogonal to the first polarization.

39. The projection display system of claim 38, wherein the plurality of dichroic filters are arranged as rectangular bands across an output end of the transmitting/reflecting polarizer.