POLARIZED HEAD-MOUNTED PROJECTION DISPLAY

• US 20100002154A1
• Filed: 01/18/2008
• Published: 01/07/2010
• Est. Priority Date: 01/18/2007
• Status: Active Grant

• Current Assignee: Arizona Board of Regents (University of Arizona)
• Original Assignee: AZ BD of Regents On Behalf of The University of AZ
• Inventors: Hua, Hong
• Granted Patent: US 8,259,239 B2
• Time in Patent Office: Days
• US Class Current: 349/11
• CPC Class Codes: G02B 13/00 Optical objectives specially designed for the purposes specified below with variable magnification in general G02B15/00
• CPC Class Codes: G02B 2027/0118 comprising devices for improving the contrast of the display / brillance control visibility
• CPC Class Codes: G02B 2027/0134 of stereoscopic type
• CPC Class Codes: G02B 2027/0138 comprising image capture systems, e.g. camera
• CPC Class Codes: G02B 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 5/30 Polarising elements light-modulating devices with active elements G02F1/00

Abstract

An image display system and associated method for image displaying The system includes an image source configured to generate image light, projection optics configured to project the image light, and a polarizing beam splitter optically coupled to the projection optics and configured to propagate into a first optical path first polarized light having a first polarization and to propagate into a second optical path second polarized light having a second polarization The system includes a quarter wave converter disposed in the first optical path and configured to rotate the first polarization by a quarter phase as the first polarized light first passes through the quarter wave converter, and includes a reflective screen disposed in the first optical path and configured to reflect rotated first polarized light from the quarter wave converter back through the quarter wave converter for further quarter phase rotation.

Claims

1. An image display system comprising:

an image source configured to generate image light;

projection optics configured to project and focus said image light;

a polarizing beam splitter optically coupled to the projection optics and configured to propagate into a first optical path first polarized light having a first polarization and to propagate into a second optical path second polarized light having a second polarization;

a quarter wave converter disposed in said first optical path and configured to rotate said first polarization by a quarter phase as said first polarized light first passes through said quarter wave converter;

a reflective screen disposed in said first optical path and configured to reflect rotated first polarized light from said quarter wave converter back through said quarter wave converter for further quarter phase rotation, whereby image light of the rotated first polarized light is converted to converted image light of the second polarization, said converted image light of the second polarization propagated in said first optical path back to the polarizing beam splitter for propagation by said polarizing beam splitter; and

an output port disposed in said first optical path and configured to receive the converted image light of the second polarization propagated by the beam splitter.

2. The system of claim 1, wherein the polarizing beam splitter is configured to reflect said first polarized light onto the first optical path and to transmit said second polarized light onto the second optical path.

3. The system of claim 1, wherein the polarizing beam splitter is configured to transmit said first polarized light onto the first optical path and to reflect said second polarized light onto the second optical path.

4. The system of claim 1, wherein:

the reflective screen is disposed at a position to receive light reflected from the beam splitter,

the first polarization is S-polarized light and the second polarization is P-polarized light, and

the quarter wave converter comprises a quarter wave retarder configured to rotate the S-polarized light to become said P-polarized light before transmission through the beam splitter to the exit pupil.

5. The system of claim 1, wherein:

the reflective screen is disposed at a position to receive light transmitted through the beam splitter,

the first polarization is S-polarized light and the second polarization is P-polarized light, and

the quarter wave converter comprises a quarter wave retarder configured to rotate the P-polarized light to become said S-polarized light before reflection by the beam splitter to the exit pupil.

6. The system of claim 1, wherein the image source comprises a polarized image source aligned with one of the first or second polarizations.

7. The system of claim 6, further comprising:

a shell integrally mounting the polarized image source in alignment with the polarizing beam splitter.

8. The system of claim 1, further comprising:

a half-wave retarder disposed in an optical path between the polarized image source and the beam splitter, and configured to rotate a polarization direction of the image light from the polarized image source into at least one of the first or second polarizations to be aligned with a polarization direction of the beam splitter.

9. The system of claim 1, wherein the reflective screen comprises a retroreflective screen.

10. The system of claim 1, wherein the beam splitter comprises at least one of a wire-grid polarizer, a dichroic cube polarizing beam splitter, and a multilayer birefringent cube polarizing beam splitter.

11. The system of claim 10, wherein the wire-grid polarizer has a wire direction defining a P-polarization direction and has an orthogonal direction to the wire direction defining for an S-polarization direction.

12. The system of claim 1, wherein the image source comprises at least one of a liquid crystal display, a light emitting diode display, an organic light emitting diode display, liquid crystal on silicon display, and a ferroelectric liquid crystal on silicon display.

13. The system of claim 1, wherein the image source comprises a non-polarized image source and a polarizing element having a polarization axis aligned with one of the first and second polarizations of the beam splitter.

14. The system of claim 1, wherein:

the image source generates S-polarization image light; and

the beam splitter reflects the S-polarization image light and transmits the converted image light of the second polarization as P-polarization image light.

15. The system of claim 1, wherein:

the image source generates P-polarization image light; and

the beam splitter reflects the P-polarization image light and transmits the converted image light of the second polarization as S-polarization image light.

16. The system of claim 1, wherein the image source includes a folded mirror configured to reflect the image light to the projection optics.

17. The system of claim 1, further comprising:

a processor configured to provide video signals to said image source.

18. The system of claim 1, wherein the projection optics, the polarizing beam splitter, the reflective screen, the quarter wave converter, and the exit pupil comprise a head mounted display.

19. The system of claim 1, further comprising:

a processor configured to provide video signals to said image source, and

the projection optics, the polarizing beam splitter, the reflective screen, the quarter wave converter, and the exit pupil comprise a head mounted display.

20. The system of claim 19, wherein the head mounted display comprises:

a shell integrally mounting the projection optics, the polarizing beam splitter, the reflective screen, the quarter wave converter, and the exit pupil, and

the shell includes video feeds from the processor to said image source.

21. A method for image displaying, comprising:

generating image light from an image source;

projecting and focusing said image light from the image source;

splitting at a beam splitter first polarized light of said image light having a first polarization into a first optical path and second polarized light of said image light having a second polarization into a second optical path;

reflecting the first polarized light in the first optical path as a virtual image of the image light being focused;

converting said first polarized light into said second polarized light; and

propagating the second polarized light by the beam splitter for viewing of the virtual image.

22. The method of claim 21, wherein splitting comprises reflecting and transmitting orthogonally polarized components of the image light respectively onto the first and second paths.

23. The method of claim 21, further comprising:

converting the first polarization to a quarter wave circular polarization state prior to reflection at the reflective screen.

24. The method of claim 23, further comprising:

converting the quarter wave circular polarization state to the second polarization prior to transmission through the beam splitter to the exit pupil.

25. The method of claim 23, further comprising:

converting the quarter wave circular polarization state to the second polarization prior to reflection by the beam splitter to the exit pupil.

26. The method of claim 21, wherein generating image light comprises generating polarized image light having a polarization aligned with one of the first or second polarizations.

27. The method of claim 21, wherein generating image light comprises:

generating polarized image light; and

converting the polarized image light into at least one of the first or second polarizations.

28. The method of claim 21, wherein reflecting at a reflective screen comprises reflecting at a retroreflective screen.

29. The method of claim 21, wherein reflecting at a beam splitter comprises reflecting at least one of a wire-grid polarizer, a dichroic cube polarizing beam splitter, and a multilayer birefringent cube polarizing beam splitter.

30. The method of claim 21, wherein generating image light comprises:

generating the image light from at least one of a liquid crystal display, a light emitting diode display, an organic light emitting diode display, liquid crystal on silicon display, and a ferroelectric liquid crystal on silicon display.

31. The method of claim 21, wherein generating image light comprises:

generating a non-polarized image light and filtering the a non-polarized image light by a polarizing element having a polarization axis aligned with one of the first and second polarizations.

32. The method of claim 21, wherein generating image light comprises:

generating the image light and reflecting said image light to said beam splitter.

33. The method of claim 21, further comprising:

providing video signals to said image source.

34. The method of claim 21, wherein projecting said image light comprises:

projecting said image light into a head mounted display.

35. The method of claim 21, further comprising:

providing video signals to said image source, and

projecting said image light into a head mounted display.

36. An image display system comprising:

an image generator configured to generate image light from an image source;

a projector configured to project and focus the image light;

means for splitting first polarized light of said image light having a first polarization into a first optical path and second polarized light of said image light having a second polarization into a second optical path;

a reflective screen on the first optical paths, configured to reflect the first polarized light from the means for splitting as a virtual image of image light focused by the projection optics; and

means for converting said first polarized light into said second polarized light; and

means for propagating the second polarized light for propagation by the means for splitting for viewing of the virtual image.