System and eyewear for viewing stereoscopic imagery

• US 20090066863A1
• Filed: 09/08/2008
• Published: 03/12/2009
• Est. Priority Date: 09/07/2007
• Status: Active Grant

• Current Assignee: RealD Incorporated
• Original Assignee: Real D
• Inventors: Chen, Jianmin
• Granted Patent: US 8,279,395 B2
• Time in Patent Office: Days
• US Class Current: 349/13
• CPC Class Codes: G02F 1/13363 Birefringent elements, e.g. for optical compensation
• CPC Class Codes: G02F 1/1397 the twist being substantially higher than 90°, e.g. STN-, SBE-, OMI-LC cells
• CPC Class Codes: H04N 13/341 using temporal multiplexing
• CPC Class Codes: H04N 2213/008 Aspects relating to glasses for viewing stereoscopic images

Abstract

A super-twist nematic (STN) liquid crystal (LC) light shutter with improved contrast performance, lower power requirements and enhanced off-axis performance. Compensator components may be disposed in front of and, in some cases, behind the liquid crystal cell. In some embodiments, a STN LC cell with a twist angle of 270 degrees may be used. In other embodiments, a STN LC cell with a twist angle ranging between just greater than 270 degrees and 285 degrees may be used. Also disclosed is a system incorporating the various disclosed STN LC shutters.

Claims

1. A liquid crystal shutter lens, comprising:

a first polarizer having an absorption axis oriented in a first direction;

a second polarizer having an absorption axis oriented in a second direction and substantially orthogonal to the first direction;

a super-twisted nematic (STN) liquid crystal (LC) cell positioned between the first polarizer and the second polarizer, wherein the STN LC cell has a first buffing direction, and wherein the STN LC cell has a second buffing direction substantially 270 degrees from the first direction; and

a first compensator element between the first polarizer and the second polarizer.

2. The liquid crystal shutter lens of claim 1, wherein the first buffing direction is orientated in substantially the same direction as the first direction.

3. The liquid crystal shutter lens of claim 1, wherein the first buffing direction is oriented substantially perpendicular to the first direction.

4. The liquid crystal shutter lens of claim 1, wherein the first compensator element is a biaxial compensator.

5. The liquid crystal shutter lens of claim 4, further comprising a second biaxial compensator element between the second polarizer and the STN LC, wherein the first biaxial compensator element is between the first polarizer and the STN LC.

6. The liquid crystal shutter lens of claim 5, wherein the second biaxial compensator has a slow axis oriented at an angular range of zero to ten degrees relative to the absorption axis of the second polarizer.

7. The liquid crystal shutter lens of claim 5, wherein the first biaxial compensator has a slow axis oriented at an angular range of zero to ten degrees relative to the absorption axis of the first polarizer.

8. The liquid crystal shutter lens of claim 6, wherein the first biaxial compensator has a slow axis parallel to the absorption axis of the first polarizer.

9. The liquid crystal shutter lens of claim 1, wherein the first compensator element is an A-plate.

10. The liquid crystal shutter lens of claim 9, wherein the A-plate has a retardance in the range of 5 and 100 nm.

11. The liquid crystal shutter lens of claim 1, wherein the first compensator element is a negative c-plate.

12. The liquid crystal shutter lens of claim 11, wherein the negative c-plate has a retardance in the range between 200 and 500 nm.

13. Eyewear for viewing stereoscopic content, comprising:

a first shutter lens comprising;

a first polarizer having an absorption axis oriented in a first direction;

a second polarizer having an absorption axis oriented in a second direction and substantially orthogonal to the first direction;

a first super-twisted nematic (STN) liquid crystal (LC) cell positioned between the first polarizer and the second polarizer, wherein the first STN LC cell has a first buffing direction, and wherein the first STN LC cell has a second buffing direction substantially 270 degrees from the first direction;

a first biaxial compensator element between the first polarizer and the first STN LC cell;

a second biaxial compensator element between the second polarizer and the first STN LC cell;

a second shutter lens comprising;

a third polarizer having an absorption axis oriented in a third direction;

a fourth polarizer having an absorption axis oriented in a fourth direction and substantially orthogonal to the third direction;

a second super-twisted nematic (STN) liquid crystal (LC) cell positioned between the third polarizer and the fourth polarizer, wherein the second STN LC cell has a third buffing direction, and wherein the second STN LC cell has a fourth buffing direction substantially 270 degrees from the third direction;

a third biaxial compensator element between the third polarizer and the second STN LC cell; and

a fourth biaxial compensator element between the fourth polarizer and the second STN LC cell.

14. The eyewear of claim 13, wherein the first buffing direction is orientated in substantially the same direction as the first direction, and wherein the third buffing direction is orientated in substantially the same direction as the third direction.

15. The eyewear of claim 13, wherein the first buffing direction is oriented substantially perpendicular to the first direction, and wherein the third buffing direction is oriented substantially perpendicular to the third direction.

16. The eyewear of claim 13, further comprising a controller communicatively coupled to the first and second shutter lenses.

17. A stereoscopic viewing system, comprising:

eyewear comprising;

left and right eye shutters, each shutter comprising a super-twisted nematic (STN) liquid crystal (LC) cell and at least one compensator element between first and second orthogonal polarizers; and

a receiver operable to receive synchronization information to alternately operate the left and right eye shutters between a light-transmitting state and a light-blocking state, the receiver being coupled to the left and right eye shutters.

18. The stereoscopic viewing system of claim 17, further comprising a transmitter operable to transmit the synchronization information.

19. A liquid crystal shutter lens, comprising:

a first polarizer having an absorption axis oriented in a first direction;

a second polarizer having an absorption axis oriented in a second direction and substantially orthogonal to the first direction;

a super-twisted nematic (STN) liquid crystal (LC) cell positioned between the first polarizer and the second polarizer, wherein the STN LC cell has a first buffing direction, and wherein the STN LC cell has a second buffing direction greater than 270 degrees from the first direction.

20. The liquid crystal shutter lens of claim 19, wherein the first buffing direction is orientated in substantially the same direction as the first direction.

21. The liquid crystal shutter lens of claim 19, wherein the first buffing direction is orientated substantially perpendicular to the first direction.

22. The liquid crystal shutter lens of claim 19, wherein the STN LC has a twist angle ranging between just greater than 270 degrees and 285 degrees.

23. The liquid crystal shutter lens of claim 19, wherein the STN LC has a twist angle of substantially 275 degrees.

24. The liquid crystal shutter lens of claim 19, further comprising a first compensator element located between the STN LC cell and the first polarizer, the first compensator element having a slow axis oriented in a third direction.

25. The liquid crystal shutter lens of claim 24, wherein the third direction is in a range of zero to ten degrees from the first direction.

26. The liquid crystal shutter lens of claim 24, wherein the first compensator element is an A-plate.

27. The liquid crystal shutter lens of claim 26, wherein the A-plate has a retardance in the range of 5 and 100 nm.

28. The liquid crystal shutter lens of claim 24, wherein the first compensator element is a negative c-plate.

29. The liquid crystal shutter lens of claim 24, wherein the first compensator element is a biaxial plate.

30. The liquid crystal shutter lens of claim 29, further comprising a second compensator element located between the STN LC cell and the second polarizer, the first compensator element having a slow axis oriented in a fourth direction.

31. A liquid crystal shutter lens, comprising:

a first polarizer having an absorption axis oriented in a first direction;

a second polarizer having an absorption axis oriented in a second direction and substantially orthogonal to the first direction;

a third polarizer having in absorption axis oriented substantially parallel to the first direction;

a first super-twisted nematic (STN) liquid crystal (LC) cell positioned between the first polarizer and the second polarizer, wherein the first STN LC cell has a twist angle of 270 degrees;

a second STN LC cell positioned between the first polarizer and the second polarizer, wherein the second STN LC cell has a twist angle of 270 degrees; and

at least one compensator element between the first and third polarizers.