Controlling polarization for liquid crystal displays

• US 20060262255A1
• Filed: 12/09/2005
• Published: 11/23/2006
• Est. Priority Date: 05/23/2005
• Status: Active Grant

• Current Assignee: Min-Shine Chow Wang, Ran-Hong Raymond Wang
• Original Assignee: Min-Shine Chow Wang, Ran-Hong Raymond Wang
• Inventors: Wang, Min-Shine Chow, Wang, Ran-Hong Raymond
• Granted Patent: US 8,274,631 B2
• Time in Patent Office: Days
• US Class Current: 349/114
• CPC Class Codes: G02F 1/133555 Transflectors
• CPC Class Codes: G02F 1/133638 Waveplates, i.e. plates with a retardation value of lambda/n

Abstract

Certain embodiments of liquid crystal displays and liquid crystal display functional parts have low reflection for outdoor applications. Various embodiments also have the advantage of being able to provide increased contrast and brightness for certain convenient viewing directions for outdoor viewers wearing polarized sunglasses.

Claims

1. A reflective functional part integrated transflective display comprising:

a transflective liquid crystal display module having a module front surface that selectively outputs linearly polarized light oriented along a first linear polarization axis, said liquid crystal display module comprising a liquid crystal cell, a partial reflector, and a backlight module;

a first retarder layer forward said liquid crystal display module, said first retarder layer having a front surface, a rear surface, a retardance of about (2n+1)λ

/4, and a first slow axis, which forms an angle θ

₁ to said first linear polarization axis, where n is an integer and λ

is between about 400 nm to 700 nm;

a reflective functional part forward said first retarder layer, said reflective functional part having a rear surface and comprising at least one of a resistive touch panel, an EMI shield, an infrared filter, and an LCD heater;

a second retarder layer forward said reflective functional part, said second retarder layer having a second slow axis and a retardance of about (2m+1)λ

/4, where m is an integer and λ

is between about 400 nm to 700 nm;

a second linear polarizer forward said second retarder layer, said second linear polarizer having a second polarization axis, which forms an angle θ

₂ to said second slow axis of said second retarder layer; and

a display front surface through which light from said backlight module exits.

2. The display of claim 1, wherein said partial reflector comprises reflective electrodes or a reflective sheet member positioned at the rear side of said liquid crystal cell.

3. The display of claim 1, wherein said display module front surface includes an anti-reflection treatment or is laminated to said rear surface of said first retarder layer.

4. The display of claim 3, wherein at least one of said first retarder layer front surface and said reflective functional part rear surface includes at least one of an anti-reflection treatment and a diffusing structure, said anti-reflection treatment comprising an AR coating or a laminated sheet member with an AR coating.

5. The display of claim 1, further comprising a third retarder layer forward said second linear polarizer, said third retarder layer comprising one or more retarders oriented such that light from said back light module exits as elliptical or circular polarized light.

6. The display of claim 1, wherein said display front surface comprises an anti-reflection treatment.

7. A reflective functional part integrated transflective display comprising:

a liquid crystal display module having a module front surface, said liquid crystal display module comprising, from front to rear, a liquid crystal cell, a partial reflector comprising a reflective polarizer having a first linear polarization axis, and a light module;

a first retarder layer forward said liquid crystal display module, said first retarder layer having a front surface, a rear surface, a retardance of about (2n+1)λ

/4, and a first slow axis, which forms an angle θ

₁ to said first linear polarization axis, where n is an integer and λ

is between about 400 nm to 700 nm;

a reflective functional part forward said first retarder layer, said reflective functional part having a rear surface and comprising at least one of a resistive touch panel, an EMI shield, an infrared filter, and an LCD heater;

a second retarder layer forward said reflective functional part, said second retarder layer having a second slow axis and a retardance of about (2m+1)λ

/4, where m is an integer and λ

is between about 400 nm to 700 nm;

a second linear polarizer forward said second retarder layer, said second linear polarizer having a second polarization axis, which forms an angle θ

₂ to said second slow axis of said second retarder layer; and

a display front surface through which light from the light module exits.

8. The display of claim 7, wherein said liquid crystal display module further comprises a third linear polarizer between said liquid crystal cell and said partial reflector, said third linear polarizer having a rear surface.

9. The display of claim 8, wherein said partial reflector further comprises a diffusing structure.

10. The display of claim 9, wherein said diffusing structure comprises a corrugated diffusing surface or an adhesive layer laminating said third linear polarizer to said reflective polarizer.

11. The display of claim 8, wherein said liquid crystal display module further comprises a fourth linear polarizer forward said liquid crystal cell, said fourth linear polarizer having a front surface.

12. The display of claim 11, wherein said partial reflector further comprises a diffusing structure.

13. The display of claim 12, wherein said diffusing structure comprises a corrugated diffusing surface or an adhesive layer laminating said third linear polarizer to said reflective polarizer.

14. The display of claim 7, wherein said module front surface includes an anti-reflection treatment or is laminated to said rear surface of said first retarder layer.

15. The display of claim 14, wherein at least one of said first retarder layer front surface and said reflective functional part rear surface includes at least one of an anti-reflection treatment and a diffusing structure, said anti-reflection treatment comprising a multi-layer AR coating or a laminated sheet member with AR coating.

16. The display of claim 7, further comprising a third retarder layer forward said second linear polarizer, said third retarder layer comprising one or more retarders oriented such that said light exits as elliptical or circular polarized light.

17. The display of claim 7, wherein said display front surface comprises an anti-reflection treatment.

18. A reflective functional part integrated display comprising:

a liquid crystal display module having a module front surface that selectively outputs linearly polarized light oriented along a first linear polarization axis, said liquid crystal display module comprising, from front to rear, a liquid crystal cell, and a light module;

a reflective functional part forward said liquid crystal display module, said reflective functional part having a rear surface and comprising at least one of a resistive touch panel, an EMI shield, an infrared filter and an LCD heater;

a second retarder layer forward said reflective functional part, said second retarder layer having a second slow axis and a retardance of about (2m+1)λ

/4, where m is an integer and λ

is between about 400 nm to 700 nm;

a second linear polarizer forward said second retarder layer, said second linear polarizer having a second polarization axis, which forms an angle θ

₂ to said second slow axis of said second retarder layer; and

a display front surface through which light from said light module exits,

wherein said liquid crystal display module front surface includes at least one of an anti-reflection treatment and a diffusing structure, said anti-reflection treatment comprising a multi-layer AR coating or a laminated sheet member with AR coating.

19. The display of claim 18, further comprising a first retarder layer between said reflective functional part and said liquid crystal display module, said first retarder layer having a rear surface, a retardance of about (2n+1)λ

/4, and a first slow axis which forms an angle θ

₁ to said first linear polarization axis, where n is an integer and λ

is between about 400 nm to 700 nm.

20. The display of claim 19, wherein θ

₁ is between about +25°

to about +65° and

θ

₂ is about +45°

, or θ

₁ is between about −

25°

to about −

65° and

θ

₂ is about −

45°

when (m+n) is zero or an even integer.

21. The display of claim 19, wherein θ

₁ is between about +25°

to about +65° and

θ

₂ is about −

45°

, or θ

₁ is between about −

25°

to about −

65° and

θ

₂ is about +45°

when (m+n) is an odd integer.

22. The display of claim 19, wherein said second linear polarization axis of said second linear polarizer is oriented at about 0°

with respect to said first linear polarization axis of said liquid crystal display module linearly polarized light.

23. The display of claim 19, wherein said liquid crystal display module further comprises a third linear polarizer between said liquid crystal cell and light module.

24. The display of claim 23, wherein said liquid crystal display module further comprises a partial reflector between said third linear polarizer and said light module.

25. The display of claim 24, wherein said partial reflector comprises a reflective polarizer.

26. The display of claim 25, wherein said partial reflector further comprises a diffusing structure.

27. The display of claim 26, wherein said diffusing structure comprises a corrugated diffusing surface or an adhesive layer laminating said third linear polarizer to said reflective polarizer.

28. The display of claim 23, wherein said liquid crystal display module further comprises a fourth linear polarizer forward said liquid crystal cell.

29. The display of claim 28, wherein said liquid crystal display module further comprises a partial reflector between said third linear polarizer and said light source.

30. The display of claim 29, wherein said partial reflector comprises a reflective polarizer.

31. The display of claim 30, wherein said partial reflector further comprises a diffusing structure.

32. The display of claim 31, wherein said diffusing structure comprises a corrugated diffusing surface or an adhesive layer laminating said third linear polarizer to said reflective polarizer.

33. The display of claim 19, wherein said first retarder layer is laminated to said reflective functional part rear surface.

34. The display of claim 33, wherein said first retarder layer rear surface includes at least one of an anti-reflection treatment and a diffusing structure, said anti-reflection treatment comprising a multi-layer AR coating or a laminated sheet member with AR coating.

35. The display of claim 18, further comprising a third retarder layer forward said second linear polarizer, said third retarder layer comprising one or more retarders oriented such that said light exits as elliptical or circular polarized light.

36. The display of claim 18, wherein said display front surface comprises an anti-reflection treatment.

37. A reflective functional part integrated display comprising:

a liquid crystal display module having a module front surface that selectively outputs linearly polarized light oriented along a first linear polarization axis, said liquid crystal display module comprising, from front to rear, a liquid crystal cell and a light module;

a first retarder layer forward said liquid crystal display module, said first retarder layer having a front surface, a retardance of about (2n+1)λ

/4, and a first slow axis which forms an angle θ

₁ to said first linear polarization axis, where n is an integer and λ

is between about 400 nm to 700 nm;

a reflective functional part forward said first retarder layer, said reflective functional part having a rear surface and comprising at least one of a resistive touch panel, an EMI shield, an infrared filter and an LCD heater;

a second retarder layer forward of said reflective functional part, said second retarder layer having a second slow axis and a retardance of about (2m+1)λ

/4, where m is an integer and λ

is between about 400 nm to 700 nm;

a second linear polarizer forward said second retarder layer, said second linear polarizer having a second polarization axis, which forms an angle θ

₂ to said second slow axis of said second retarder layer; and

a display front surface through which light exits,

wherein at least one of said first retarder layer front surface and said reflective functional part rear surface includes at least one of an anti-reflection treatment and a diffusing structure, said anti-reflection treatment comprising a multi-layer AR coating or a laminated sheet member with AR coating.

38. The display of claim 37, wherein said liquid crystal display module further comprises a third linear polarizer between said liquid crystal cell and said light module.

39. The display of claim 38, wherein said liquid crystal display module further comprises a partial reflector between said third linear polarizer and said light module.

40. The display of claim 39, wherein said partial reflector comprises a reflective polarizer.

41. The display of claim 40, wherein said partial reflector further comprises a diffusing structure.

42. The display of claim 41, wherein said diffusing structure comprises a corrugated diffusing surface or an adhesive layer laminating said third linear polarizer to said reflective polarizer.

43. The display of claim 38, wherein said liquid crystal display module further comprises a fourth linear polarizer forward said liquid crystal cell.

44. The display of claim 43, wherein said liquid crystal display module further comprises a partial reflector between said third linear polarizer and said light module.

45. The display of claim 44, wherein said partial reflector comprises a reflective polarizer.

46. The display of claim 45, wherein said partial reflector further comprises a diffusing structure.

47. The display of claim 46, wherein said diffusing structure comprises a corrugated diffusing surface or an adhesive layer laminating said third linear polarizer to said reflective polarizer.

48. The display of claim 37, wherein said first retarder layer is laminated to said liquid crystal display module front surface.

49. The display of claim 37, further comprising a third retarder layer forward said second linear polarizer, said third retarder layer comprising one or more retarders oriented such that said light exits as elliptical or circular polarized light.

50. The display of claim 37, wherein said display front surface comprises an anti-reflection treatment.