Image projection system

• US 5,975,703 A
• Filed: 09/30/1996
• Issued: 11/02/1999
• Est. Priority Date: 09/30/1996
• Status: Expired due to Term

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Digital Optics International Corporation
• Inventors: Holman, Robert L., Cox, Arthur
• Primary Examiner(s): DOWLING, WILLIAM C
• Application Number:
  US08/724,734
• Time in Patent Office: 1,128 Days
• Field of Search: 353/20, 353/31, 353/7, 353/8, 349/9, 349/8, 359/464, 359/465, 359/472, 359/497, 359/501, 359/495, 359/494
• US Class Current: 353/20
• 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 21/62 Translucent screens

Abstract

An image projection device having a spatial light modulator and a polarized source system for illuminating the spatial light modulator such that light of a first polarization state illuminates one region of the spatial light modulator and light of a second polarization state illuminates another region of the spatial light modulator. Preferably, the image projection device includes a first set of polarization selective light processing elements, including a first conicoid element which passes light of the first polarization state and reflects light of the second polarization state and a second set of polarization selective light processing elements including a second conicoid element which passes light of the second polarization state and reflects light of the first polarization state.

Claims

1. An image projection system, comprising:

means for generating image information including a spatial light modulator;

a polarized light source system for illuminating said spatial light modulator such that light of a first polarization state from the light source system covers one region of said spatial light modulator and light of a second polarization state from the light source system covers another region of said spatial light modulator;

a screen for viewing the image information;

a projection lens for enlarging and projecting the image information as images onto said screen;

a first set of polarization selective light processing elements including a first conicoid element which passes light of the first polarization state and reflects light of the second polarization state and further including a first optical element for converting light of the first polarization state into the second polarization state, thereby enabling output of light of the second polarization state onto one portion of the screen for viewing; and

a second set of polarization selective light processing elements including a second conicoid element which passes light of said second polarization state and reflects light of said first polarization state and further including a second optical element for converting light of the second polarization state into the first polarization state, thereby enabling output of light of the first polarization state onto another portion of the screen for viewing.

2. The image projection system as defined in claim 1 wherein said first optical element and said second optical element comprise at least one of a curved mirror and a surface inclined from perpendicularity relative to said screen.

3. The image projection system as defined in claim 1 wherein said first and second conicoid elements include aspherized surfaces.

4. The image projection system as defined in claim 1 wherein said conicoid elements are modified by adjusting at least one of conicoid eccentricity, conicoid major axis and conicoid aspheric terms.

5. The image projection system as defined in claim 1 wherein said first conicoid element and said first optical element are disposed on one side of an optic axis of said image projection system.

6. The image projection system as defined in claim 1 wherein said first conicoid element and said second optical element are disposed on one side of an optic axis of said image projection system.

7. The image projection system are defined in claim 1 further including a polarization converting mirror disposed on an optic axis of said image projection system.

8. The image projection system as defined in claim 1 wherein the first optical element is disposed parallel to said screen.

9. The image projection system as defined in claim 1 wherein the first and second conicoid elements are disposed substantially parallel to said screen.

10. The image projection system as defined in claim 1 further including means for beam displacement for overlapping images of said one portion and said another portion of the screen.

11. The image projection system as defined in claim 1 wherein said first and second optical elements comprise conicoids.

12. An image projection system, comprising:

means for generating image information including a spatial light modulator having a characteristic input aperture shape;

a polarized light source for illuminating said spatial light modulator such that light of a first polarization state covers one region of said spatial light modulator and light of a second polarization state orthogonal to the first polarization state covers another region of said spatial light modulator;

a screen for viewing the image information;

a projection lens for enlarging and projecting the image information as images onto said screen;

a first set of polarization selective light reflecting elements including a first reflecting element which passes light of the first polarization state and reflects light of the second polarization state, and a second reflecting element which converts light of the first polarization state into light of the second polarization state with an image output beam from the second reflecting element being reflected from said first reflecting element and light of the second polarization state output for viewing on one portion of said screen; and

a second set of polarization selective light reflecting elements including a third reflecting element which passes light of the second polarization state and reflects light of the first polarization state, and a fourth reflecting element which converts light of the second polarization state into light of the first polarization state with the image output beam from the fourth reflecting element being reflected from said third reflecting element and light of the first polarization state output for viewing on a second portion of said screen.

13. The image projection system as defined in claim 12 further including a polarization beam splitter for separating light of the first polarization state from light of the second polarization state, and light of the first polarization state processed by said first set of light reflecting elements and said light of the second polarization state processed by said second set of light reflecting elements.

14. The image projection system as defined in claim 13 wherein said polarization beam splitter comprises a prism having a first layer for transmitting light of wide band colors and of the first polarization state and reflecting light of the second polarization state, and a second layer for transmitting light of wide band colors and of the second polarization state and reflecting light of the first polarization state.

15. The image projection system as defined in claim 14 wherein said second layer for reflecting the separated light of first polarization state, and said first layer for reflecting the separated light of second polarization state cause the reflected light of both the first and second polarization states to have parallel beam paths of substantially opposite directions.

16. The image projection system as define in claim 13 wherein said beam splitter includes a wide band quarter wave retardation layer for changing polarization state of at least one of the light of first and second polarization state.

17. The image projection system as defined in claim 13 wherein said beam splitter comprises a 45°

prism and a parallelepiped.

18. The image projection system as defined in claim 13 wherein said beam splitter comprises four 45°

prisms and a beam-directing element.

19. An image projection system, comprising:

means for generating image information including a spatial light modulator;

a polarized light source system for illuminating said spatial light modulator with polarized light, said polarized light source system comprised of means for transmitting light of a first polarization state and a polarization selective reflector and a conicoid including a polarization converting layer and a reflecting layer for processing light of a second polarization into the first polarization state with the recycled light being transmitted through the means for transmitting light;

a beam shaping element disposed between said polarized light source system and said spatial light modulator;

a screen for viewing the image information; and

a projection lens for enlarging and projecting the image information as images onto said screen.

20. The image projection system as defined in claim 19 further including a composite refractive element for producing a diverging output beam of light.

21. The image projection system as defined in claim 20 further including a convergent output lens element to converge the diverging output beam of light.

22. The image projection system as defined in claim 21 wherein said polarized light source system further includes reciprocating mirror elements for recycling peripheral light and repositioning the peripheral light within the converged output beam of light.

23. The image projection system as defined in claim 19 further including means for performing a rectangular beam shape transformation.

24. The image projection system as defined in claim 19 wherein said polarization selective reflector is selected from the group consisting of a substantially planar layer and a conicoid.

25. The image projection system as defined in claim 19 further including means for correction of a hole in a light beam from said light source.

26. The image projection system as defined in claim 25 wherein means are provided to fill the hole with black rays having no image information by including means for providing a buffer zone.

27. The image projection system as defined in claim 26 further including means for beam displacement for collapsing the buffer zone to form a continuous image on said screen.

28. The image projection system as defined in claim 19 wherein said polarized light source system comprises a converging type light source system.

29. The image projection system as defined in claim 28 wherein said converging type light source system is selected from the group consisting of an ellipsoidal system, a paraboloidal system and a CURL-type system.

30. An image projection system, comprising:

means for generating image information including a spatial light modulator;

a polarized light source system for illuminating said spatial light modulator, said light source system comprised of a light source and a reflector for producing light of at least a first and second polarization state;

a screen for viewing the image information with the screen having a first and second portion;

a projection lens for enlarging and projecting the image information as images onto said screen; and

a set of light reflecting and polarization converting elements for receiving the light from said polarized light source system and from said projection lens, said set of elements converting polarization state of the light and reflecting the light of at least two polarization states onto said screen for viewing, and said set of light reflecting and polarization converting elements disposed for selectively reflecting light of the first and second polarization states and also for selectively converting light of the first polarization state to the second polarization state and likewise converting light of the second polarization state to the first polarization state with the light of first polarization state being applied to the first portion of the screen and the light of second polarization state being applied to the second portion of the screen.

31. The image projection system as defined in claim 30 wherein said set of light reflecting and polarization converting elements comprises a conicoid selected from the group consisting of an ellipsoid, a paraboloid and a hyperboloid.

32. The image projection system as defined in claim 31 wherein said conicoid shape is modified by an aspherizing function.

33. The image projection system as defined in claim 30 further including a beam shaping element comprised of a beam sizing element.