Autostereoscopic display with a passive cycloidal diffractive waveplate

• US 9,237,337 B2
• Filed: 08/24/2012
• Issued: 01/12/2016
• Est. Priority Date: 08/24/2011
• Status: Active Grant

• Current Assignee: Reald Spark, LLC
• Original Assignee: RealD Incorporated
• Inventors: Ramsey, Robert A., Robinson, Michael G.
• Primary Examiner(s): Kostak, Victor
• Application Number:
  US13/593,625
• Publication Number:
  US 20130050452A1
• Time in Patent Office: 1,236 Days
• Field of Search: 348/51, 348/54, 348/58, 345/6, 349/15
• US Class Current: 1/1
• CPC Class Codes: G09G 3/003 to produce spatial visual effects
• CPC Class Codes: H04N 13/305 using lenticular lenses, e.g. arrangements of cylindrical lenses
• CPC Class Codes: H04N 13/307 using fly-eye lenses, e.g. arrangements of circular lenses
• CPC Class Codes: H04N 13/366 using viewer tracking

Abstract

A new beam deflection approach is provided for displaying images in autostereoscopic format. Conceptually, polarized light from a display is directed into specific viewing regions using a polarization-sensitive beam deflection sub-system that comprises, in exemplary embodiments, an active liquid crystal quarter-wave plate modulator and a passive cycloidal grating element, such as a diffractive waveplate. Specific embodiments may comprise an illumination system that both floods an LCD panel and creates a defined eye pupil region, from within which the display is viewable. Deflecting the pupil region between left and right eye positions in synchronization with displayed frame sequential stereo image data creates desirable autostereoscopic 3D viewing. Other embodiments employ a similar beam deflection sub-system in conjunction with a means of viewing subsets of pixels from different viewing positions, such as a parallax barrier or lenslet array, allowing freedom of head movement while maintaining stereo viewing.

Claims

1. An autostereoscopic display, comprising:

a display panel providing stereoscopic imagery;

a polarization modulator configured to modify polarization of light received from the display panel, wherein the polarization modulator is configured to impart right-handed or left-handed circular polarization on light received from the display panel; and

a polarization-sensitive beam deflector configured to direct light received from the polarization modulator based on the modified polarization.

2. The autostereoscopic display according to claim 1, wherein the handedness of the left-handed and right-handed circular polarized light corresponds to either left eye or right eye images of the stereoscopic imagery.

3. The autostereoscopic display according to claim 1, wherein the polarization modulator imparts the right-handed or left-handed circular polarization based on corresponding first and second voltages applied to the polarization modulator.

4. The autostereoscopic display according to claim 1, wherein the polarization modulator imparts the right-handed or left-handed circular polarization by imparting a positive or negative approximately quarter-wave phase retardance on linearly polarized light received from the display panel.

5. The autostereoscopic display according to claim 4, wherein the polarization modulator comprises an in-plane switching device that reorients a quarter-wave phase retardance through a right angle substantially symmetrically about the input linear polarization direction.

6. The autostereoscopic display according to claim 4, wherein the polarization modulator comprises two approximately orthogonally oriented quarter-wave modulators.

7. The autostereoscopic display according to claim 4, wherein the polarization modulator comprises an approximately 45°

oriented half-wave retarder and an approximately orthogonally oriented passive quarter-wave retarder.

8. The autostereoscopic display according to claim 1, wherein polarization modulator is a liquid crystal modulator.

9. The autostereoscopic display according to claim 1, wherein the polarization-sensitive beam deflector is configured to respectively direct the left-handed and right-handed circular polarized light into either left or right eye viewing regions based on the handedness of the circular polarized light.

10. The autostereoscopic display according to claim 9, wherein the polarization-sensitive beam deflector comprises at least one static cycloidal diffractive waveplate, each comprising diffraction angles determined as a function of wavelength of the left-handed and right-handed circular polarized light.

11. The autostereoscopic display according to claim 9, further comprising a parallax barrier configured to direct alternating left eye and right eye imagery to corresponding left eye and right eye viewing regions.

12. The autostereoscopic display according to claim 9, further comprising a lenslet array configured to direct alternating left eye and right eye imagery to corresponding left eye and right eye viewing regions.

13. The autostereoscopic display according to claim 12, wherein the lenslet array comprises a plurality of vertical lenses configured to direct alternating left eye and right eye imagery to corresponding left eye and right eye viewing regions.

14. The autostereoscopic display according to claim 1, further comprising a linear polarizer configured to linearly polarize light output from the display system, and to provide the linearly polarized light to the polarization modulator.

15. The autostereoscopic display according to claim 1, wherein the display panel comprises an OLED light source.

16. An autostereoscopic display for providing stereoscopic imagery, comprising:

a display panel providing stereoscopic imagery;

a polarization modulator configured to impart right-handed or left-handed circular polarization, corresponding to either left eye or right eye images of the stereoscopic imagery, on linearly polarized light received from the display panel; and

a polarization-sensitive beam deflector configured to respectively direct the left-handed and right-handed circular polarized light into either left or right eye viewing regions based on the handedness of the circular polarized light.

17. The autostereoscopic display according to claim 16, wherein the polarization modulator imparts the right-handed or left-handed circular polarization based on corresponding first and second voltages applied to the polarization modulator.

18. The autostereoscopic display according to claim 16, wherein the polarization modulator imparts the right-handed or left-handed circular polarization by imparting a positive or negative approximately quarter-wave phase retardance on linearly polarized light received from the display panel.

19. The autostereoscopic display according to claim 18, wherein the polarization modulator comprises an in-plane switching device that reorients a quarter-wave phase retardance through a right angle substantially symmetrically about the input linear polarization direction.

20. The autostereoscopic display according to claim 18, wherein the polarization modulator comprises two approximately orthogonally oriented quarter-wave modulators.

21. The autostereoscopic display according to claim 18, wherein the polarization modulator comprises an approximately 45°

oriented half-wave retarder and an approximately orthogonally oriented passive quarter-wave retarder.

22. The autostereoscopic display according to claim 16, wherein polarization modulator is a liquid crystal modulator.

23. The autostereoscopic display according to claim 16, wherein the polarization-sensitive beam deflector comprises at least one static cycloidal diffractive waveplate, each comprising diffraction angles determined as a function of wavelength of the left-handed and right-handed circular polarized light.

24. The autostereoscopic display according to claim 16, further comprising a parallax barrier configured to direct alternating left eye and right eye imagery to corresponding left eye and right eye viewing regions.

25. The autostereoscopic display according to claim 16, further comprising a lenslet array configured to direct alternating left eye and right eye imagery to corresponding left eye and right eye viewing regions.

26. The autostereoscopic display according to claim 25, wherein the lenslet array comprises a plurality of vertical lenses configured to direct alternating left eye and right eye imagery to corresponding left eye and right eye viewing regions.

27. The autostereoscopic display according to claim 16, further comprising a linear polarizer configured to linearly polarize light output from the display system, and to provide the linearly polarized light to the polarization modulator.

28. The autostereoscopic display according to claim 16, wherein the display panel comprises an OLED light source.

29. A method of providing stereoscopic imagery, the method comprising:

receiving light from a display panel configured to provide stereoscopic imagery;

modulating the polarization of light received from the display panel, wherein modulating the polarization of light received from the display panel comprises imparting right-handed or left-handed circular polarization on light received from a display system providing stereoscopic imagery; and

directing the modulated light based on the modulated polarization.

30. The method according to claim 29, wherein the handedness of the left- and right-handed circular polarized light corresponds to either left eye or right eye images of the stereoscopic imagery.

31. The method according to claim 29, wherein imparting right-handed or left-handed circular polarization on the linearly polarized light comprises using corresponding positive or negative quarter-wave phase retardance.

32. The method according to claim 29, wherein directing the modulated light based on the modulated polarization comprises directing the left-handed and right-handed circular polarized light respectively into either left or right eye viewing regions based on the handedness of the circular polarized light.

33. The method according to claim 32, wherein directing the left-handed and right-handed circular polarization comprises employing at least one cycloidal diffractive waveplate, each comprising diffraction angles determined as a function of wavelength of the left-handed and right-handed circular polarized light.

34. The method according to claim 29, further comprising directing alternating left eye and right eye imagery to a plurality of corresponding left eye and right eye viewing regions.

35. The method according to claim 29, further comprising linearly polarizing light output from the display panel, and providing the linearly polarized light to the polarization modulator.