Optical retarder stack pair for transforming input light into polarization states having saturated color spectra

• US 5,999,240 A
• Filed: 05/09/1997
• Issued: 12/07/1999
• Est. Priority Date: 05/23/1995
• Status: Expired due to Term

• Current Assignee: RealD Incorporated
• Original Assignee: ColorLink, Incorporated (RealD Incorporated)
• Inventors: Sharp, Gary D., Johnson, Kristina M.
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): Parker, Kenneth
• Application Number:
  US08/853,461
• Time in Patent Office: 942 Days
• Field of Search: 349/18, 349/119, 349/120, 349/106, 349/121, 356/351, 356/361, 356/362, 356/365, 356/368, 359/634, 359/494, 359/495, 359/497, 359/498, 359/491
• US Class Current: 349/119
• CPC Class Codes: G02B 27/288 Filters employing polarising elements, e.g. Lyot or Solc filters G02B5/3016 takes precedence
• CPC Class Codes: G02B 5/3083 Birefringent or phase retarding elements G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001
• CPC Class Codes: G02F 1/0136 for the control of polarisation, e.g. state of polarisation [SOP] control, polarisation scrambling, TE-TM mode conversion or separation G02F1/0353 takes precedence
• CPC Class Codes: G02F 1/0322 Arrangements comprising two or more independently controlled crystals
• CPC Class Codes: G02F 1/09 based on magneto-optical elements, e.g. exhibiting Faraday effect
• CPC Class Codes: G02F 1/133533 Colour selective polarisers G02F1/1347 takes precedence
• CPC Class Codes: G02F 1/133536 Reflective polarizers G02F1/13362 takes precedence
• CPC Class Codes: G02F 1/133543 Cholesteric polarisers
• CPC Class Codes: G02F 1/1336 Illuminating devices
• CPC Class Codes: G02F 1/13363 Birefringent elements, e.g. for optical compensation
• CPC Class Codes: G02F 1/133638 Waveplates, i.e. plates with a retardation value of lambda/n
• CPC Class Codes: G02F 1/13473 for wavelength filtering or for colour display without the use of colour mosaic filters
• CPC Class Codes: G02F 1/23 for the control of the colour G02F1/03 - G02F1/21 take precedence
• CPC Class Codes: G02F 2413/04 Number of plates greater than or equal to 4
• CPC Class Codes: G02F 2413/08 with a particular optical axis orientation
• CPC Class Codes: H04N 5/66 Transforming electric information into light information scanning details H04N3/00
• CPC Class Codes: H04N 5/7441 the modulator being an array of liquid crystal cells
• CPC Class Codes: H04N 9/3111 for displaying the colours sequentially, e.g. by using sequentially activated light sources sequential projection in colour photography G03B33/08
• CPC Class Codes: H04N 9/3126 for spatial light modulators in series
• CPC Class Codes: H04N 9/3167 for polarizing the light beam polarizing optical systems per se G02B27/28

Abstract

A retarder stack for transforming at least partially polarized light includes a first retarder and a second retarder. The first retarder has a first retardance and a first orientation and the second retarder has a second retardance and a second orientation both orientations with respect to the partially polarized light. The first retardance, first orientation, second retardance, and second orientation can be arranged to yield the desired polarization transformed light which includes a first spectrum and a second spectrum. The polarization of the first spectrum and the polarization of the second spectrum can be made orthogonal to each other. The polarizations can be linear or elliptical. If the polarization transformed light is linear, the directions of polarizations are different and in one case can be made perpendicular. If the polarization of the polarization transformed light is elliptical, then the polarizations are different and in on case can be made orthogonal in the general sense of orthogonality of polarization states.

Claims

1. An apparatus, comprising:

a first retarder stack for receiving at least partially polarized input light and providing a first transformation of said input light into transformed light; and

a second retarder stack for receiving at least a portion of said transformed light and providing a second transformation that transforms said transformed light into output light, wherein said first and second transformations polarize said output light into at least a first polarization state having a first saturated spectrum and a second polarization state having a second saturated spectrum, said first retarder stack and said second retarder stack positioned such that an at least partially transmissive material can be placed between said first and second retarder stacks.

2. The apparatus as claimed in claim 1, wherein a spectrum of said input light comprises a white light spectrum.

3. The apparatus as claimed in claim 1, wherein at least one of said first and second saturated spectrums comprises a color spectrum.

4. The apparatus as claimed in claim 3, wherein the at least one of said first and second saturated spectrums comprises a saturated color spectrum.

5. The apparatus as claimed in claim 1, wherein said input light has an initial spectrum which is not a white light spectrum, and at least one of said first and second saturated spectrums is within said initial spectrum.

6. The apparatus as claimed in claim 5, wherein at least one of said first and second saturated spectrums comprises a color spectrum.

7. The apparatus of claim 6, wherein said color spectrum comprises a saturated color spectrum.

8. The apparatus as claimed in claim 1, wherein said first retarder stack comprises:

a first retarder having a first retardance and a first orientation with respect to said input light for receiving said input light and outputting initially transformed light; and

a second retarder having a second retardance and a second orientation with respect to said input light for receiving said initially transformed light and outputting said transformed light, said first and second orientations being different.

9. The apparatus as claimed in claim 1, wherein said second retarder stack comprises:

a first retarder having a first retardance and a first orientation with respect to said input light; and

a second retarder having a second retardance and a second orientation with respect to said input light for receiving light from the first retarder and outputting said output light, said first and second orientations being different.

10. The apparatus as claim in claim 1, wherein:

said first retarder stack comprises a first plurality of N retarders, wherein N≧

2, having a respective first plurality of retardances Γ

_N and a respective first plurality of orientations α

_N with respect to said input light; and

said second retarder stack comprises a second plurality of N retarders, wherein N≧

2, having a respective second plurality of retardances Γ

'"'"'_N and a respective second plurality of orientations α

'"'"'_N with respect to said input light.

11. The apparatus as claimed in claim 10, wherein each of said first plurality of orientations α

_N is unique within said first plurality of N retarders.

12. The apparatus as claimed in claim 10, wherein each of said first plurality of retardances Γ

_N is unique within said first plurality of N retarders.

13. The apparatus as claimed in claim 10, wherein each of said second plurality of orientations α

'"'"'_N is unique within said plurality of N retarders.

14. The apparatus as claimed in claim 10, wherein each of said second plurality of retardances Γ

'"'"'_N is unique within said second plurality of N retarders.

15. The apparatus as claimed in claim 10, wherein each of said orientations α

'"'"'_N is equal to α

_N ±

90.

16. The apparatus as claimed in claim 10, wherein the retardances and orientations of said first retarder stack and said second retarder stack correspond to a Fan olc design.

17. The apparatus as claimed in claim 10, wherein the retardances and orientations of said first retarder stack and said second retarder stack correspond to a quasi-folded olc design.

18. The apparatus as claimed in claim 10, wherein the retardances and orientations of said first retarder stack and said second retarder stack correspond to a split-element design.

19. The apparatus as claimed in claim 1, wherein

said first retarder stack comprises a first plurality of N retarders, wherein N≧

2, having a respective plurality of retardances Γ

₁, Γ

₂. . . Γ

_N and a respective plurality of orientations α

₁, α

₂. . . α

_N ; and

said second retarder stack comprises a second plurality of N retarders, wherein N≧

2, having a respective plurality of retardances Γ

_N. . . Γ

₂, Γ

₁ and having a respective plurality of orientations 90±

α

_N. . . 90±

α

₂, 90±

α

₁.

20. The apparatus as claimed in claim 1, wherein a spectrum of said input light comprises a non-visible spectrum.

21. The apparatus as claimed in claim 1, wherein at least one of said first and second saturated spectrums comprises at least one band of wavelengths of moderate resolution.

22. The apparatus as claimed in claim 21, wherein said at least one band of wavelengths has a full-width-half-maximum value of at least 70 nm.

23. The apparatus as claimed in claim 21, wherein said at least one band of wavelengths has a full-width-half-maximum value of at least 97 nm.

24. The apparatus as claimed in claim 21, wherein said at least one band of wavelengths lies within a range of visible wavelengths.

25. The apparatus as claimed in claim 24, wherein said range of visible wavelengths define a color.

26. The apparatus as claimed in claim 25, wherein said color comprises an additive primary color.

27. The apparatus as claimed in claim 25, wherein said color comprises a subtractive primary color.

28. The apparatus as claimed in claim 21, wherein said at least one band of wavelengths lies within a range of non-visible wavelengths.

29. The apparatus as claimed in claim 21, wherein said at least one band of wavelengths approximately conforms to a band of wavelengths within a spectrum of said input light.

30. The apparatus as claimed in claim 1, wherein at least one of said first and second saturated spectrums comprises a periodic spectrum.

31. The apparatus as claimed in claim 1, wherein at least one of said first and second saturated spectrums comprises a multi-peak spectrum.

32. The apparatus as claimed in claim 31, wherein each peak in said multi-peak spectrum is separated by at least one null.

33. An apparatus, comprising:

a first retarder stack for receiving at least partially polarized input light and providing a first transformation of said input light into transformed light; and

a second retarder stack for receiving at least a portion of said transformed light and providing a second transformation that transforms said transformed light into output light, wherein said first and second transformations polarize said output light into at least a first polarization state having a first saturated spectrum and a second polarization state having a second saturated spectrum, said first retarder stack and said second retarder stack positioned such that an at least partially transmissive material, when placed between said first and second retarder stacks, modifies the polarization of said transformed light in a known fashion;

wherein, when the at least partially transmissive material is present between the first and second retarder stacks, the output light has a spectrum and polarization which is approximately the same as a spectrum and polarization of the input light.

34. The apparatus as claimed in claim 33, wherein the spectrum of said input light comprises a white light spectrum.

35. The apparatus as claimed in claim 33, wherein the spectrum of said input light is not a white light spectrum.

36. The apparatus as claimed in claim 33, wherein said first stack retarder comprises:

a first retarder having a first retardance and a first orientation with respect to said input light for receiving said at least partially polarized light and outputting initially transformed light; and

a second retarder having a second retardance and a second orientation with respect to said input light for receiving said initially transformed light and outputting said transformed light, said first and second orientations being different.

37. The apparatus as claimed in claim 33, wherein said second retarder stack comprises:

a first retarder having a first retardance and a first orientation with respect to said input light; and

a second retarder having a second retardance and a second orientation with respect to said input light for receiving said light from the first retarder and outputting said output light, said first and second orientations being different.

38. The apparatus as claimed in claim 33, wherein:

said first retarder stack comprises a first plurality of N retarders, wherein N≧

2, having a respective first plurality of retardances Γ

_N and a respective first plurality of orientations α

_N with respect to said input light; and

said second retarder stack comprises a second plurality of N retarders, wherein N≧

2, having a respective second plurality of retardances Γ

'"'"'_N and a respective second plurality of orientations α

'"'"'_N with respect to said input light.

39. The apparatus as claimed in claim 38, wherein each of said first plurality of orientations α

_N is unique within said first plurality of N retarders.

40. The apparatus as claimed in claim 38, wherein each of said first plurality of retardances Γ

_N is unique within said first plurality of N retarders.

41. The apparatus as claimed in claim 38, wherein each of said second plurality of orientations α

'"'"'_N retarders is unique within said second plurality of N retarders.

42. The apparatus as claimed in claim 38, wherein each of said second plurality retardances Γ

'"'"'_N is unique within said second plurality of N retarders.

43. The apparatus as claimed in claim 38, wherein each of said orientations α

'"'"'_N is equal to α

_N ±

90.

44. The apparatus as claimed in claim 38, wherein the retardances and orientations of said first retarder stack and said second retarder stack correspond to a Fan olc design.

45. The apparatus as claimed in claim 38, wherein the retardances and orientations of said first retarder stack and said second retarder stack correspond to a quasi-folded olc design.

46. The apparatus as claimed in claim 38, wherein the retardances and orientations of said first retarder stack and said second retarder stack correspond to a split-element design.

47. The apparatus as claimed in claim 33, wherein

said first retarder stack comprises a first plurality of N retarders, wherein N≧

2, having a respective plurality of retardances Γ

₁, Γ

₂. . . Γ

_N and a respective plurality of orientations α

₁, α

₂. . . α

_N ; and

said second retarder stack comprises a second plurality of N retarders, wherein N≧

2, having a respective plurality of retardances Γ

_N. . . Γ

₂, Γ

₁ and having a respective plurality of orientations 90±

α

_N. . . 90±

α

₂, 90±

α

₁.

48. The apparatus as claimed in claim 33, wherein a spectrum of said input light comprises a non-visible spectrum.

49. The apparatus as claimed in claim 33, wherein at least one of said first and second saturated spectrums comprises a color spectrum.

50. The apparatus as claimed in claim 49, wherein said color spectrum comprises a saturated color spectrum.

51. An apparatus, comprising:

a first retarder stack for receiving at least partially polarized input light and providing a first transformation of said input light into transformed light having a spectrum and polarization that is different than the spectrum and polarization of said input light; and

a second stack for receiving at least a portion of said transformed light and providing a second transformation that transforms said transformed light into output light with a spectrum and polarization which is substantially the same as the spectrum and polarization of said input light, said first retarder stack and said second retarder stack positioned such that an at least partially transmissive material can be placed between said first and second retarder stacks.

52. The apparatus as claimed in claim 51, wherein a spectrum of said input light comprises a white light spectrum.

53. The apparatus of claim 51, wherein a spectrum of said input light is not a white light spectrum.

54. The apparatus as claimed in claim 51, wherein said first retarder stack comprises:

a first retarder having a first retardance and a first orientation with respect to said input light for receiving said input light and outputting initially transformed light; and

a second retarder having a second retardance and a second orientation with respect to said input light for receiving said initially transformed light and outputting said transformed light, said first and second orientations being different.

55. The apparatus as claimed in claim 51, wherein said second retarder stack comprises:

a first retarder having a first retardance and a first orientation with respect to said input light; and

a second retarder having a second retardance and a second orientation with respect to said input light for receiving light from the first retarder and outputting said output light, said first and second orientations being different.

56. The apparatus as claimed in claim 51, wherein:

said first retarder stack comprises a first plurality of N retarders, wherein N≧

2, having a respective first plurality of retardances Γ

_N and a respective first plurality of orientations α

_N with respect to said input light; and

said second retarder stack comprises a second plurality of N retarders, wherein N≧

2, having a respective second plurality of retardances Γ

'"'"'_N and a respective second plurality of orientations α

'"'"'_N with respect to said input light.

57. The apparatus as claimed in claim 56, wherein each of said first plurality of orientations α

_N is unique within said first plurality of N retarders.

58. The apparatus as claimed in claim 56, wherein each of said first plurality of retardances Γ

_N is unique within said first plurality of N retarders.

59. The apparatus as claimed in claim 56, wherein each of said second plurality of orientations α

'"'"'_N is unique within said second plurality of N retarders.

60. The apparatus as claimed in claim 56, wherein each of said second plurality of retardances Γ

'"'"'_N is unique within said second plurality of N retarders.

61. The apparatus as claimed in claim 56, wherein each of said orientations α

'"'"'_N is equal to α

_N ±

90.

62. The apparatus as claimed in claim 56, wherein the retardances and orientations of said first retarder stack and said second retarder stack correspond to a Fan olc design.

63. The apparatus as claimed in claim 56, wherein the retardances and orientations of said first retarder stack and said second retarder stack correspond to a quasi-folded olc design.

64. The apparatus as claimed in claim 56, wherein the retardances and orientations of said first retarder stack and said second retarder stack correspond to a split-element design.

65. The apparatus as claimed in claim 51, wherein a spectrum of said input light comprises a non-visible spectrum.

66. An apparatus, comprising:

a first polarizer for receiving input light and outputting at least partially polarized light;

a first retarder stack for receiving said at least partially polarized light and providing a first transformation of said at least partially polarized light into transformed light; and

a second retarder stack for receiving at least a portion of said transformed light and providing a second transformation that transforms said transformed light into output light, wherein said first and second transformations polarize said output light into at least a first polarization state having a first saturated spectrum and a second polarization state having a second saturated spectrum, said first retarder stack and said second retarder stack positioned such that an at least partially transmissive material can be placed between said first and second retarder stacks; and

a second polarizer for analyzing the polarization of said output light.

67. The apparatus as claimed in claim 66, wherein a spectrum of said input light comprises a white light spectrum.

68. The apparatus as claimed in claim 66, wherein at least one of said first and second saturated spectrums comprises a color spectrum.

69. The apparatus as claimed in claim 68, wherein said color spectrum comprises a saturated color spectrum.

70. The apparatus as claimed in claim 66, wherein said input light has an initial spectrum which is not a white light spectrum, and at least one of said first and second saturated spectrums is within said initial spectrum.

71. The apparatus as claimed in claim 70, wherein said at least one of said first and second saturated spectrums comprises a color spectrum.

72. The apparatus as claimed in claim 71, wherein the at least one of said first and second saturated spectrums comprises a saturated color spectrum.

73. The apparatus as claimed in claim 66, wherein said first retarder stack comprises:

a first retarder having a first retardance and a first orientation with respect to the at least partially polarized light for receiving the at least partially polarized light and outputting initially transformed light; and

a second retarder having a second retardance and a second orientation with respect to the at least partially polarized light for receiving said initially transformed light and outputting said transformed light, said first and second orientations being different.

74. The apparatus as claimed in claim 66, wherein said second retarder stack comprises:

a first retarder having a first retardance and a first orientation with respect to the at least partially polarized light; and

a second retarder having a second retardance and a second orientation with respect to the at least partially polarized light for receiving light from the first retarder and outputting said output light, said first and second orientations being different.

75. The apparatus as claimed in claim 66, wherein:

said first retarder stack comprises a first plurality of N retarders, wherein N≧

2, having a respective first plurality of retardances Γ

_N and a respective first plurality of orientations α

_N with respect to the at least partially polarized light; and

said second retarder stack comprises a second plurality of N retarders, wherein N≧

2, having a respective second plurality of retardances Γ

'"'"'_N and a respective second plurality of orientations α

'"'"'_N with respect to the at least partially polarized light.

76. The apparatus as claimed in claim 75, wherein each of said first plurality of orientations α

_N is unique within said first plurality of N retarders.

77. The apparatus as claimed in claim 75, wherein each of said first plurality of retardances Γ

_N is unique within said first plurality of N retarders.

78. The apparatus as claimed in claim 75, wherein each of said second plurality of orientations α

'"'"'_N is unique within said second plurality of N retarders.

79. The apparatus as claimed in claim 75, wherein each of said second plurality of retardances Γ

'"'"'_N is unique within said second plurality of N retarders.

80. The apparatus as claimed in claim 75, wherein each of said orientations α

'"'"'_N is equal to α

_N ±

90.

81. The apparatus as claimed in claim 75, wherein the retardances and orientations of said first retarder stack and said second retarder stack correspond to a Fan olc design.

82. The apparatus as claimed in claim 75, wherein the retardances and orientations of said first retarder stack and said second retarder stack correspond to a quasi-folded olc design.

83. The apparatus as claimed in claim 75, wherein the retardances and orientations of said first retarder stack and said second retarder stack correspond to a split-element design.

84. The apparatus as claimed in claim 66, wherein

said first retarder stack comprises a first plurality of N retarders, wherein N≧

2, having a respective plurality of retardances Γ

₁, Γ

₂. . . Γ

_N and a respective plurality of orientations α

₁, α

₂. . . α

_N ; and

said second retarder stack comprises a second plurality of N retarders, wherein N≧

2, having a respective plurality of retardances Γ

_N. . . Γ

₂, Γ

₁ and having a respective plurality of orientations 90±

α

_N. . . 90±

α

₂, 90±

α

₁.

85. The apparatus as claimed in claim 66, wherein a spectrum of the at least partially polarized light comprises a non-visible spectrum.