Imbedded wire grid polarizer for the visible spectrum

• US 6,288,840 B1
• Filed: 01/11/2000
• Issued: 09/11/2001
• Est. Priority Date: 06/22/1999
• Status: Expired due to Term

• Current Assignee: Moxtek (Polatechno Co.,Ltd.)
• Original Assignee: Moxtek (Polatechno Co.,Ltd.)
• Inventors: Gardner, Eric W., Hansen, Douglas P., Perkins, Raymond T.
• Primary Examiner(s): SCHUBERG, DARREN E
• Application Number:
  US09/480,393
• Time in Patent Office: 609 Days
• Field of Search: 359/485, 359/486
• US Class Current: 359/485.03
• CPC Class Codes: G02B 5/1809 with pitch less than or comparable to the wavelength
• CPC Class Codes: G02B 5/3058 comprising electrically conductive elements, e.g. wire grids, conductive particles

Abstract

An embedded wire grid polarizer for the visible spectrum includes an array of parallel, elongated, spaced-apart elements sandwiched between first and second layers. The elements form a plurality of gaps between the elements which provide a refractive index less than the refractive index of the first layer. Regions may be formed between the elements and the first and/or second layers which also provide a refractive index which is less than the refractive index of the layers. The regions may be formed by film layers or ribs/grooves formed in the layers.

Claims

1. An embedded wire grid polarizer for the visible spectrum, the polarizer comprising:

a first layer having a refractive index;

a second layer, separate from the first layer, having a refractive index; and

an array of parallel, elongated, spaced-apart elements, sandwiched between the first and second layers, and forming a plurality of gaps between the elements, the gaps providing a refractive index less than the refractive index of the first layer.

2. The polarizer of claim 1, wherein the gaps between the elements include air.

3. The polarizer of claim 1, wherein the gaps between the elements have a vacuum.

4. The polarizer of claim 1, wherein gaps between the elements include a material different from materials of the first and second layers.

5. The polarizer of claim 1, wherein the gaps between the elements includes a material the same as a material of one of the first and second layers.

6. The polarizer of claim 1, wherein the gaps between the elements include water.

7. The polarizer of claim 1, wherein the gaps between the elements include magnesium fluoride.

8. The polarizer of claim 1, wherein the gaps between the elements include oil.

9. The polarizer of claim 1, wherein the gaps between the elements include hydrocarbon.

10. The polarizer of claim 1, wherein the first and second layers each have a thickness greater than 1 micron;

and wherein the elements have a thickness between 0.04 to 1 microns.

11. The polarizer of claim 1, wherein the elements have a period less than 0.3 microns;

wherein the elements have widths less than 0.15 microns; and

wherein the gaps have widths less than 0.15 microns.

12. The polarizer of claim 1, wherein the first layer further has a first surface facing the elements, and the elements further have first surfaces facing the first layer and defining an imaginary plane extending across the first surfaces of the elements;

and further comprising;

a region, between the imaginary plane and the first surface of the first layer, providing a refractive index which is less than the refractive index of the first layer.

13. The polarizer of claim 1, wherein the first layer has a first surface, and wherein the elements are disposed on the first surface of the first layer;

and further comprising;

a plurality of grooves formed in the first surface of the first layer between the elements.

14. The polarizer of claim 13, wherein the grooves have a depth between approximately 0.001 to 3 microns.

15. The polarizer of claim 1, wherein the first and second layers have respective first and second surfaces between which the elements are disposed;

and further comprising;

a first plurality of grooves formed in the first surface of the first layer between the elements; and

a second plurality of grooves formed in the second surface of the second layer between the elements.

16. The polarizer of claim 1, further comprising:

a film, disposed between the first layer and the elements, having a refractive index which is less than the refractive index of the first layer.

17. The polarizer of claim 16, wherein the refractive index of the film is between approximately 1 and 1.7.

18. The polarizer of claim 16, wherein the film has a thickness between approximately 0.01 and 5 microns.

19. The polarizer of claim 16, wherein the film includes a dielectric material.

20. The polarizer of claim 19, wherein the dielectric material of the film includes magnesium fluoride.

21. The polarizer of claim 1, further comprising:

a first film, disposed between the first layer and the elements, having a refractive index which is less than the refractive index of the first layer; and

a second film, disposed between the second layer and the elements, having a refractive index which is less than the refractive index of the second layer.

22. The polarizer of claim 1, further comprising:

an array of parallel, elongated, spaced-apart ribs, extending from the first layer towards the elements and oriented parallel with the elements with one rib extending towards each element.

23. The polarizer of claim 22, wherein the array of ribs provides a refractive index less than the refractive index of the first layer.

24. The polarizer of claim 22, wherein the ribs include magnesium fluoride.

25. The polarizer of claim 22, wherein the ribs include silicon dioxide.

26. The polarizer of claim 1, further comprising:

a film, disposed between the first layer and the elements; and

a plurality of grooves, formed in the film between the elements.

27. The polarizer of claim 26, wherein the film has a refractive index less than the refractive index of the first layer.

28. The polarizer of claim 26, wherein the film has a refractive index between approximately 1 and 1.7.

29. The polarizer of claim 26, wherein the film has a thickness between approximately 0.01 and 5 microns.

30. The polarizer of claim 1, wherein the elements are disposed in a cube, and oriented diagonal to at least one cube surface.

31. The polarizer of claim 1, wherein the elements are disposed between and oriented parallel with respect to a pair of transparent plates.

32. The polarizer of claim 1, wherein the array has a configuration and the elements have a size which would normally create a resonance effect in combination with one of the layers within the visible spectrum;

and wherein the gaps with a lower refractive index than the refractive index of one of the layers causes a shift of the normally occurring resonance effect to a lower wavelength, thereby broadening a band of visible wavelengths in which no resonance effect occurs.

33. The polarizer of claim 1, wherein the array of elements is configured to interact with electromagnetic waves of light in the visible spectrum to generally reflect most the light of a first polarization and transmit most the light of a second polarization.

34. An imbedded wire grid polarizer for the visible spectrum, the polarizer comprising:

first and second separate layers having respective first and second surfaces facing towards one another, and respective first and second refractive indices;

an array of parallel, elongated, spaced-apart elements, sandwiched between the first and second surfaces of the first and second layers, the elements having first surfaces facing towards the first surface of the first layer and defining an imaginary plane extending across the first surfaces of the elements; and

a region, between the imaginary plane extending across the first surfaces of the elements and the first surface of the first layer, having a refractive index which is less than the refractive index of the first layer.

35. The polarizer of claim 34, wherein the region includes a plurality of grooves formed in the first surface of the first layer between the elements.

36. The polarizer of claim 35, wherein the grooves have a depth between approximately 0.001 to 3 microns.

37. The polarizer of claim 34, wherein the elements further have second surfaces facing the second surface of the second layer and defining a second imaginary plane extending across the second surfaces of the elements;

and further comprising;

a second region, between the second imaginary plane extending across the second surfaces of the elements and the second surface of the second layer, having a refractive index which is less than the refractive index of the second layer.

38. The polarizer of claim 37, wherein the regions include:

a first plurality of grooves formed in the first surface of the first layer between the elements; and

a second plurality of grooves formed in the second surface of the second layer between the elements.

39. The polarizer of claim 34, wherein the region includes:

a film, disposed between the first layer and the elements, having a refractive index which is less than the refractive index of the first layer.

40. The polarizer of claim 39, wherein the refractive index of the film is between approximately 1 and 1.7.

41. The polarizer of claim 39, wherein the film has a thickness between approximately 0.01 and 5 microns.

42. The polarizer of claim 39, wherein the film includes a dielectric material.

43. The polarizer of claim 42, wherein the film includes magnesium fluoride.

44. The polarizer of claim 37, wherein the regions include:

a first film, disposed between the first layer and the elements, having a refractive index which is less than the refractive index of the first layer; and

a second film, disposed between the second layer and the elements, having a refractive index which is less than the refractive index of the second layer.

45. The polarizer of claim 34, wherein the region includes:

an array of parallel, elongated, spaced-apart ribs, extending from the first layer towards the elements.

46. The polarizer of claim 45, wherein the ribs include magnesium fluoride.

47. The polarizer of claim 45, wherein the ribs include silicon dioxide.

48. The polarizer of claim 34, wherein the region includes:

a film, disposed between the first layer and the elements; and

a plurality of grooves, formed in the film between the elements.

49. The polarizer of claim 48, wherein the film has a refractive index between approximately 1 and 1.7.

50. The polarizer of claim 48, wherein the film has a thickness between approximately 0.01 and 5 microns.

51. The polarizer of claim 34, wherein the array of elements forms a plurality of gaps between the elements, the gaps providing a refractive index less than the refractive index of one of the layers.

52. The polarizer of claim 51, wherein the gaps between the elements include air.

53. The polarizer of claim 51, wherein the gaps between the elements have a vacuum.

54. The polarizer of claim 51, wherein the gaps between the elements include a material different from materials of the first and second layers.

55. The polarizer of claim 51, wherein the gaps between the elements include a material the same as a material of one of the first and second layers.

56. The polarizer of claim 51, wherein the gaps between the elements include water.

57. The polarizer of claim 51, wherein the gaps between the elements include magnesium fluoride.

58. The polarizer of claim 51, wherein the gaps between the elements include oil.

59. The polarizer of claim 51, wherein the gaps between the elements include hydrocarbon.

60. The polarizer of claim 51, wherein the array has a configuration and the elements have a size which would normally create a resonance effect in combination with one of the layers within the visible spectrum;

and wherein the gaps with a lower refractive index than the refractive index of one of the layers causes a shift of the normally occurring resonance effect to a lower wavelength, thereby broadening a band of visible wavelengths in which no resonance effect occurs.

61. The polarizer of claim 34, wherein the first and second layers each have a thickness greater than 1 micron;

and wherein the elements have a thickness between 0.04 to 1 microns.

62. The polarizer of claim 34, wherein the elements have a period less than 0.3 microns;

wherein the elements have a width less than 0.15 microns; and

wherein the elements are separated by spaces with widths less than 0.15 microns.

63. The polarizer of claim 34, wherein the elements are disposed in a cube, and oriented diagonal to at least one cube surface.

64. The polarizer of claim 34, wherein the elements are disposed between and oriented parallel with respect to a pair of transparent plates.

65. The polarizer of claim 34, wherein the array of elements is configured to interact with electromagnetic waves of light in the visible spectrum to generally reflect most the light of a first polarization and transmit most the light of a second polarization.

66. An embedded wire grid polarizer for the visible spectrum, the polarizer comprising:

a substrate having a first surface and a first refractive index;

an array of parallel, elongated, spaced-apart elements, coupled to and oriented parallel to the substrate, configured to interact with electromagnetic waves of light in the visible spectrum to generally reflect most the light of a first polarization and transmit most the light of a second polarization, and forming a plurality of gaps between the elements, the gaps providing a refractive index less than the first refractive index of the substrate; and

a layer, coupled to and oriented parallel to the array of elements, having a second refractive index.

67. The device of claim 66, wherein the array has a configuration and the elements have a size which would normally create a resonance effect in combination with the substrate within the visible spectrum;

and wherein the gaps with a lower refractive index than the first refractive index of the substrate causes a shift of the normally occurring resonance effect to a lower wavelength, thereby broadening a band of visible wavelengths in which no resonance effect occurs.

68. The device of claim 66, wherein the elements further have first surfaces facing the first surface of the substrate and defining an imaginary plane extending across the first surfaces of the elements;

and further comprising;

a region, between the imaginary plane extending across the first surfaces of the elements and the first surface of the substrate, the region providing a refractive index which is less than the first refractive index of the substrate.

69. The device of claim 66, wherein the elements further have second surfaces facing the second surface of the second layer and defining a second imaginary plane extending across the second surfaces of the elements;

and further comprising;

a second region, between the second imaginary plane extending across the second surfaces of the elements and the second surface of the second layer, the region providing a refractive index which is less than the refractive index of the second layer.