Controlling polarization for liquid crystal displays

• US 7,633,583 B2
• Filed: 05/23/2005
• Issued: 12/15/2009
• 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
• Primary Examiner(s): Duong; Thoi V
• Application Number:
  US11/135,609
• Publication Number:
  US 20060262258A1
• Time in Patent Office: 1,667 Days
• Field of Search: 349/117, 349/119, 349/96, 349/12, 349/59, 349/16, 349/161, 349/114, 349/137, 349/64, 349/21, 349/72, 349/105, 359/86, 345/173
• US Class Current: 349/117
• 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 and 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 functional part integrated display having a display front surface through which modulated light exits, said display comprising:

a TFT liquid crystal display cell configured to modulate light, said liquid crystal display cell defining vertical and horizontal axes, said liquid crystal cell comprising a liquid crystal layer sandwiched between two sheets of transparent electrodes;

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

/4, where n is zero or a positive integer and λ

is between about 400 nm to 700 nm;

an anti-reflection treatment forward said front surface of said first retarder layer;

a functional element forward of said first retarder layer and said anti-reflection treatment, said functional element comprising at least one of an EMI shield, an infrared filter, a touch panel or an LCD heater;

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

/4, where m is zero or a positive integer and λ

is between about 400 nm to 700 nm; and

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

₂ with respect to said second slow axis,

wherein said display front surface comprises an anti-reflection treatment.

2. The display of claim 1, wherein said second linear polarization axis is oriented at about 90°

with respect to said horizontal axis of said liquid crystal cell.

3. The display of claim 1, further comprising at least one of a diffusing element, a reflective polarizer, or a brightness enhancement film rearward of said liquid crystal layer, said diffusing element comprising a diffusing adhesive layer, diffusing particles, or a corrugated diffusing surface, said diffusing element having a haze in the range between about 10% to 85%.

4. The display of claim 3, wherein said second linear polarization axis is set at about 90°

with respect to said horizontal axis of said liquid crystal cell.

5. The display of claim 3, further comprising a third retarder layer forward of said second linear polarizer, said third retarder layer comprising one or more retarders such that said modulated light exits said display front surface as elliptical or circular polarized light.

6. The display of claim 1, further comprising a third retarder layer forward of said second linear polarizer, said third retarder layer comprising one or more retarders such that said modulated light exits said display front surface as elliptical or circular polarized light.

7. The display of claim 1, further comprising a first linear polarizer forward said liquid crystal cell, said first linear polarizer having a front surface and a first linear polarization axis which forms an angle θ

₁ with respect to said first slow axis of said first retarder layer.

8. The display of claim 7, wherein said 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

₂is about −

45°

when said functional element is isotropic and (m+n) is 0 or an even integer.

9. The display of claim 7, wherein said 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 said functional element is isotropic and (m+n) is an odd integer.

10. The display of claim 7, wherein the first retarder layer is configured such that the first slow axis is oriented at an angle of approximately 0 degrees or approximately 90 degrees with respect to said horizontal axis of said liquid crystal cell.

11. The display of claim 7, further comprising at least one of a diffusing element, a reflective polarizer, or a brightness enhancement film rearward of said liquid crystal cell, said diffusing element comprising a diffusing adhesive layer, diffusing particles, or a corrugated diffusing surface, and said diffusing element having a haze in the range between about 10% to 85%.

12. The display of claim 11, further comprising a third retarder layer forward of said second linear polarizer, said third retarder layer comprising one or more retarders such that said modulated light exits said display front surface as elliptical or circular polarized light.

13. The display of claim 11, comprising a diffusing element and a reflective polarizer, wherein said reflective polarizer is positioned rearward of said diffusing element.

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

15. The display of claim 7, wherein at least one of said first retarder layer or said second retarder layer includes an optically transmissive conductive film thereon thereby forming at least a part of said functional element.

16. The display of claim 15, wherein said rear surface of said first retarder layer is adhered to said front surface of first linear polanzer.

17. The display of claim 7, wherein said rear surface of said first retarder layer is adhered to said front surface of said first linear polarizer.

18. The display of claim 1, wherein at least one of said first retarder layer or said second retarder layer includes an optically transmissive conductive film thereon thereby forming at least a part of said functional element.

19. The display of claim 1, wherein said the second linear polarizer is formed on or laminated to the second retarder layer.

20. A functional part integrated display having a display front surface through which modulated light exits, said display comprising:

a TFT liquid crystal cell configured to modulate light, said liquid crystal cell defining vertical and horizontal axes, said TFT liquid crystal cell comprising a liquid crystal layer sandwiched between two sheets of substantially optically transmissive electrodes;

a diffusing element rearward said liquid crystal layer;

a first linear polarizer forward said TFT liquid crystal cell, said first linear polarizer having a first linear polarization axis and a front surface;

a first retarder layer forward said first linear polarizer, 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 zero or a positive integer and λ

is between about 400 nm to 700 nm, and said rear surface has an anti-reflection treatment or is attached to said front surface of said first linear polarizer;

a functional element forward of said first retarder layer, said functional element comprising at least one of an EMI shield, an infrared filter, a touch panel or an LCD heater;

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

/4, where m is zero or a positive integer and λ

is between about 400 nm to 700 nm; and

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

₂ to said second slow axis of said second retarder layer,

wherein m+n≠

0 and said display front surface includes an anti-reflective treatment.

21. The display of claim 20, wherein said θ

hd 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 even integer.

22. The display of claim 20, wherein said θ

₁ is between about +25°

to about +65° and

θ

₂ is about −

45°

, or θ

is between about −

25°

to about −

65° and

θ

₂ is about 45°

when (m +n) is an odd integer.

23. The display of claim 20, wherein said second linear polarization axis is oriented at about 90°

with respect to said horizontal axis of said liquid crystal cell.

24. The display of claim 20, further comprising a reflective polarizer or a brightness enhancement film rearward of said liquid crystal layer.

25. The display of claim 24, wherein said second linear polarization axis is oriented at about 90°

with respect to said horizontal axis of said liquid crystal cell.

26. The display of claim 24, further comprising a third retarder layer forward said second linear polarizer, said third retarder layer comprising one or more retarders such that said modulated light exits said display front surface as elliptical or circular polarized light.

27. The display of claim 20, wherein an optically transmissive conductive film is disposed on the front surface of said first retarder layer or on the rear surface of said second retarder layer thereby forming at least one of an EMI shield, an infrared filter, a touch panel, and an LCD heater functional element.

28. The display of claim 27, wherein said second linear polarization axis is oriented at about 90°

with respect to said horizontal axis of said liquid crystal cell.

29. The display of claim 27, further comprising a reflective polarizer or a brightness enhancement film rearward of said liquid crystal layer.

30. The display of claim 29, wherein said second linear polarization axis is oriented at about 90°

with respect to said horizontal axis of said liquid crystal cell.

31. The display of claim 29, further comprising a third retarder layer forward said second linear polarizer oriented such that said modulated light exits said display front surface as elliptical or circular polarized light.

32. The display of claim 27, further comprising a third retarder layer forward said second linear polarizer oriented such that said modulated light exits said display front surface as elliptical or circular polarized light.

33. The display of claim 20, further comprising a third retarder layer forward said second linear polarizer, said third retarder layer comprising one or more retarders such that said modulated light exits the display front surface as elliptical or circular polarized light.

34. The display of claim 20, wherein said the second linear polarizer is formed on or laminated to the second retarder layer.

35. A functional part integrated liquid crystal display having a display front surface through which modulated light exits, said display comprising:

a liquid crystal cell configured to modulate light, said liquid crystal cell defining vertical and horizontal axes, said liquid crystal cell comprising a liquid crystal layer sandwiched between two sheets of transparent electrodes;

a first retarder forward said liquid crystal cell, said first retarder having a rear surface, a first slow axis, and a retardance of about (2n+1)λ

/4, where n is zero or a positive integer and λ

is between about 400 nm to 700 nm;

a functional element forward of said first retarder, said functional element comprising two or more of an EMI shield, an infrared filter, a touch panel or an LCD heater;

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

/4, where m is zero or a positive integer and λ

is between about 400 nm to 700 nm; and

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

₂ with respect to said second slow axis,

wherein said second slow axis of said second retarder is oriented at an angle other than about 0°

or 90°

with respect to said horizontal axis or said first slow axis of said first retarder is oriented at an angle of about 0°

or 90°

with respect to said horizontal axis, and

wherein said display front surface comprises an anti-reflection treatment.

36. The display of claim 35, wherein said second linear polarization axis is oriented at about 90°

with respect to said horizontal axis of said liquid crystal cell.

37. The display of claim 35, further comprising at least one of a diffusing element, a reflective polarizer, or a brightness enhancement film rearward of said liquid crystal layer, said diffusing element comprising an adhesive layer, diffusing particles, or a corrugated diffusing surface, and said diffusing element having a haze in the range of between about 10% to 85%.

38. The display of claim 37, wherein said second linear polarization axis is oriented at about 90°

with respect to said horizontal axis of said liquid crystal cell.

39. 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 modulated light exits said display front surface as elliptical or circular polarized light.

40. The display of claim 37, comprising a diffusing element and a reflective polarizer, wherein said reflective polarizer is positioned rearward of said diffusing element.

41. The display of claim 35, wherein at least one of said first retarder or said second retarder includes an optically transmissive conductive film thereon thereby forming at least a part of said functional element.

42. The display of claim 41, wherein said second linear polarization axis is oriented at about 90°

with respect to said horizontal axis of said liquid crystal cell.

43. The display of claim 41, further comprising at least one of a diffusing element, a reflective polarizer, or a brightness enhancement film rearward of said liquid crystal layer, said diffusing element comprising an adhesive layer, diffusing particles, or a corrugated diffusing surface, and said diffusing element having a haze in the range of between about 10% to 85%.

44. The display of claim 43, wherein said second linear polarization axis is oriented at about 90°

with respect to said horizontal axis of said liquid crystal cell.

45. The display of claim 43, further comprising a third retarder layer forward said second linear polarizer, said third retarder layer comprising one or more retarders oriented such that said modulated light exits said display front surface as elliptical or circular polarized light.

46. The display of claim 43, comprising a diffusing element and a reflective polarizer, wherein said reflective polarizer is positioned rearward of said diffusing element.

47. The display of claim 41, further comprising a third retarder layer forward said second linear polarizer, said third retarder layer comprising one or more retarders oriented such that said modulated light exits said display front surface as elliptical or circular polarized light.

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

49. The display of claim 35, further comprising a first linear polarizer forward said liquid crystal cell, said first linear polarizer having a front surface and a first linear polarization axis.

50. The display of claim 49, wherein said first slow axis is oriented at an angle of between about 2520 to 65°

or between about −

25°

to −

65°

relative to said first linear polarization axis.

51. The display of claim 49, wherein at least one of said first retarder or said second retarder includes an optically transmissive conductive film thereon thereby forming at least a part of said functional element.

52. The display of claim 51, further comprising at least one of a diffusing element, a reflective polarizer, or a brightness enhancement film rearward of said liquid crystal layer, said diffusing element comprising an adhesive layer, diffusing particles, or a corrugated diffusing surface, said diffusing element having a haze in the range of between about 10% to 85%.

53. The display of claim 51, wherein said rear surface of said first retarder has an anti-reflective treatment or is adhered to said front surface of said first linear polarizer.

54. The display of claim 49, further comprising at least one of a diffusing element, a reflective polarizer, or a brightness enhancement film rearward of said liquid crystal layer, said diffusing element comprising an adhesive layer, diffusing particles, or a corrugated diffusing surface, said diffusing element having a haze in the range of between about 10% to 85%.

55. The display of claim 49, wherein said rear surface of said first retarder has an anti-reflective treatment or is adhered to said front surface of said first linear polarizer.

56. A functional part integrated display having a display front surface through which modulated light exits, said display comprising:

TFT liquid crystal cell configured to modulate light, said liquid crystal cell defining vertical and horizontal axes, said liquid crystal cell comprising a liquid crystal layer sandwiched between two sheets of transparent electrodes;

a first retarder layer forward said liquid crystal cell, said first retarder layer having a slow axis, a front surface, a rear surface, and a retardance of about (2n+1)λ

/4, where n is zero or a positive integer and λ

is between about 400 nm to 700 nm;

an anti-reflection treatment forward said first retarder layer;

a functional element forward of said first retarder layer and said anti-reflection treatment, said functional element comprising at least one of an EMI shield, an infrared filter, a touch panel or an LCD heater; and

a circular polarizer forward said functional element, said circular polarizer having a rear surface and a second slow axis,

wherein said display front surface includes an anti-reflection treatment.

57. The display of claim 56, further comprising at least one of a diffusing element, a reflective polarizer, or a brightness enhancement film rearward of said liquid crystal layer, said diffusing element comprising an adhesive layer, diffusing particles, or a corrugated diffusing surface, said diffusing element having a haze in the range of between about 10% to 85%.

58. The display of claim 56, wherein at least one of said first retarder layer or said circular polarizer includes an optically transmissive conductive film thereon thereby forming at least a part of said functional element.

59. The display of claim 58, further comprising at least one of a diffusing element, a reflective polarizer, or a brightness enhancement film rearward of said liquid crystal layer, said diffusing element comprising an adhesive layer, diffusing particles, or a corrugated diffusing surface, said diffusing element having a haze in the range of between about 10% to 85%.

60. The display of claim 56, further comprising a first linear polarizer forward said liquid crystal cell, said first linear polarizer having a front surface and a first linear polarization axis.

61. The display of claim 60, wherein said rear surface of said first retarder layer is adhered to said front surface of said first linear polarizer.

62. The display of claim 60, wherein at least one of said first retarder layer or said circular polarizer includes an optically transmissive conductive film thereon thereby forming at least a part of said functional element.

63. The display of claim 62, further comprising at least one of a diffusing element, a reflective polarizer, or a brightness enhancement film rearward of said liquid crystal layer, said diffusing element comprising an adhesive layer, diffusing particles, or a corrugated diffusing surface, said diffusing element having a haze in the range of between about 10% to 85%.

64. A functional part integrated liquid crystal display having a display front surface through which modulated light exits, said display comprising:

a liquid crystal cell configured to modulate light, said liquid crystal cell defining vertical and horizontal axes, said liquid crystal cell comprising a liquid crystal layer sandwiched between two sheets of transparent electrodes;

a first retarder layer forward said liquid crystal cell, said retarder layer having a rear surface, a first slow axis, and a retardance of about (2n+1)λ

/4, where n is zero or a positive integer and λ

is between about 400 nm to 700 nm;

a functional element forward of said first retarder layer, said functional element comprising at least one of an EMI shield, an infrared filter or an LCD heater;

a circular polarizer forward said functional element, said circular polarizer having a rear surface and a second slow axis,

wherein said second slow axis of said circular polarizer is set at an angle other than about 0 or 90 degrees or said first slow axis of said first retarder layer is oriented at an angle of about 0°

or 90°

with respect to said horizontal axis, and

wherein said display front surface comprises an anti-reflection treatment.

65. The display of claim 64, further comprising at least one of a diffusing element, a reflective polarizer, or a brightness enhancement film rearward of said liquid crystal layer, said diffusing element comprising an adhesive layer, diffusing particles, or a corrugated diffusing surface, said diffusing element having a haze in the range of between about 10% to 85%.

66. The display of claim 64, wherein at least one of said first retarder layer or said circular polarizer includes an optically transmissive conductive film thereon thereby forming at least a part of said functional element.

67. The display of claim 66, further comprising at least one of a diffusing element, a reflective polarizer, or a brightness enhancement film rearward of said liquid crystal layer, said diffusing element comprising an adhesive layer, diffusing particles, or a corrugated diffusing surface, said diffusing element having a haze in the range of between about 10% to 85%.

68. The display of claim 64, further comprising a first linear polarizer forward said liquid crystal cell, said first linear polarizer having a front surface and a first linear polarization axis.

69. The display of claim 68, wherein said rear surface of said first retarder layer has an anti-reflective treatment or is adhered to said front surface of said first linear polarizer.

70. The display of claim 68, wherein at least one of said first retarder layer or said circular polarizer includes an optically transmissive conductive film thereon thereby forming at least a part of said functional element.

71. The display of claim 70, further comprising at least one of a diffusing element, a reflective polarizer, or a brightness enhancement film rearward of said liquid crystal layer, said diffusing element comprising an adhesive layer, diffusing particles, or a corrugated diffusing surface, said diffusing element having a haze in the range of between about 10% to 85%.

72. A functional part integrated liquid crystal display having a display front surface through which modulated light exits, said display comprising:

a liquid crystal cell configured to modulate light, said liquid crystal cell defining vertical and horizontal axes, said liquid crystal cell comprising a liquid crystal layer sandwiched between two sheets of transparent electrodes;

a first retarder forward said liquid crystal cell;

a functional element forward of said first retarder, said functional element comprising at least one of an EMI shield, an infrared filter, a touch panel or an LCD heater;

a second retarder forward said functional element, said second retarder having a second slow axis; and

a second linear polarizer forward said second retarder, said second linear polarizer having a second linear polarization axis,

wherein said second linear polarization axis is set to an angle of about 90°

with respect to said horizontal axis or said second slow axis is set at an angle other than 0°

or 90°

with respect to said horizontal axis, and

wherein said display front surface comprises an anti-reflection treatment.

73. The display of claim 72, further comprising a first linear polarizer forward said liquid crystal cell.

74. The display of claim 73, wherein at least one of said first retarder or said second retarder includes an optically transmissive conductive film thereon thereby forming at least a part of said functional element.

75. The display of claim 72, wherein said the second linear polarizer is formed on or laminated to the second retarder.

76. A functional part integrated liquid crystal display having a display front surface through which modulated light exits, said display comprising:

a liquid crystal cell configured to modulate light, said liquid crystal cell defining vertical and horizontal axes, said liquid crystal cell comprising a liquid crystal layer sandwiched between two sheets of transparent electrodes;

a first retarder layer forward said liquid crystal cell, said first retarder layer having a rear surface, a first slow axis, and a retardance of about (2n+1)λ

/4, where n is zero or a positive integer and λ

is between about 400 nm to 700 nm;

a functional element forward of said first retarder layer, said functional element comprising at least one of an EMI shield, an infrared filter, a touch panel or an LCD heater;

a circular polarizer forward said functional element, said circular polarizer having a second linear polarization axis and a second slow axis, and said second linear polarization axis is set at an angle of about 90°

with respect to said horizontal axis or said second slow axis is set at an angle other than 0°

or 90°

with respect to said horizontal axis,

wherein said display front surface includes an anti-reflection treatment.

77. The display of claim 76, wherein at least one of said first retarder layer or a second retarder comprises an optically transmissive conductive film thereby forming at least a part of said functional element.

78. The display of claim 77, wherein at least one of said first retarder layer or a second retarder include an optically transmissive conductive film thereon thereby forming at least a part of said functional element.

79. The display of claim 76, further comprising a first linear polarizer forward said liquid crystal cell.

80. The display of claim 79, wherein at least one of said first retarder layer or a second retarder comprises an optically transmissive conductive film thereon thereby forming at least a part of said functional element.