Wire grid polarizer

• US 6,665,119 B1
• Filed: 10/15/2002
• Issued: 12/16/2003
• Est. Priority Date: 10/15/2002
• Status: Expired due to Term

• Current Assignee: Moxtek Inc (Nippon Kayaku Company Limited)
• Original Assignee: Eastman Kodak Company
• Inventors: Kurtz, Andrew F., Mi, Xiang-Dong, Ramanujan, Sujatha
• Primary Examiner(s): Sugarman, Scott J.
• Assistant Examiner(s): HASAN, MOHAMMED A
• Application Number:
  US10/271,197
• Time in Patent Office: 427 Days
• Field of Search: 359/484-489, 359/495, 359/558, 359/566, 353/20, 353/31, 353/34
• US Class Current: 359/484.08
• CPC Class Codes: G02B 27/28 for polarising used in stereoscopes G02B30/25
• CPC Class Codes: G02B 5/3058 comprising electrically conductive elements, e.g. wire grids, conductive particles
• CPC Class Codes: H01Q 15/24 Polarising devices; Polarisation filters H01Q15/12, H01Q15/22 take precedence

Abstract

A wire grid polarizer (300) for polarizing an incident light beam (130) comprises a substrate having a first surface. A grid or array of parallel, elongated, composite wires (310) is disposed on the first surface (307), and each of the adjacent wires are spaced apart on a grid period less than a wavelength of incident light. Each of the wires comprises an intra-wire substructure (315) of alternating elongated metal (330a-i) wires and elongated dielectric layers (350a-i).

Claims

1. An immersed wire grid polarizer for polarizing an incident light beam, comprising:

a substrate having a surface;

an array of parallel, elongated, composite wires with intervening grooves disposed on said surface, wherein each of said composite wires are spaced apart at a grid period less than a wavelength of said incident light;

wherein each of said grooves is filled with a dielectric optical material;

wherein each of said composite wires comprises an intra-wire substructure of alternating elongated metal wires and elongated dielectric layers; and

wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers comprises at least two of said elongated metal wires.

2. An immersed wire grid polarizer according to claim 1 wherein said wire grid polarizer is oriented at an angle relative to said incident light beam such that said wire grid polarizer functions as a polarization beamsplitter and separates a transmitted polarized beam and a reflected polarized beam from said angle of said incident light beam.

3. An immersed wire grid polarizer according to claim 1 wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers supports resonance enhanced tunneling through said elongated metal wires, thereby enhancing transmission of the light of the polarization state orthogonal to said array of composite wires.

4. An immersed wire grid polarizer according to claim 1 wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers comprises at least one of said dielectric layers.

5. An immersed wire grid polarizer according to claim 1 wherein said incident light is within the range of approximately 0.4 to 1.6 μ

m in the electromagnetic spectrum.

6. An imbedded wire grid polarizer for polarizing an incident light beam, comprising:

a first dielectric substrate having a surface;

a second dielectric substrate having a surface;

an array of parallel, elongated, composite wires with intervening grooves are disposed on said surface of said first dielectric substrate, wherein each of said composite wires are spaced apart at a grid period less than a wavelength of said incident light;

wherein said array of parallel, elongated composite wires comprise a polarizing layer located between said surface of said first dielectric substrate and said surface of said second dielectric substrate;

wherein each of said composite wires comprises an intra-wire substructure of alternating elongated metal wires and elongated dielectric layers; and

wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers comprises at least two of said elongated metal wires.

7. An imbedded wire grid polarizer according to claim 6 wherein a dielectric optical material fills said grooves and contacts said surface of said second dielectric substrate.

8. An imbedded wire grid polarizer according to claim 6 wherein said wire grid polarizer is oriented at an angle relative to said incident light beam such that said wire grid polarizer functions as a polarization beamsplitter and separates a transmitted polarized beam and a reflected polarized beam from said angle of said incident light beam.

9. An imbedded wire grid polarizer according to claim 6 wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers supports resonance enhanced tunneling through said elongated metal wires, thereby enhancing transmission of the light of the polarization state orthogonal to said array of composite wires.

10. An imbedded wire grid polarizer according to claim 6 wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers comprises at least one of said dielectric layers.

11. An imbedded wire grid polarizer according to claim 6 wherein said incident light is within the range of approximately 0.4 to 1.6 μ

m in the electro-magnetic spectrum.

12. An imbedded wire grid polarizer according to claim 6 wherein said first dielectric substrate and said second dielectric substrate are fabricated to form an integrated polarizing device that is either a plate polarizer or a cube prism polarizer.

13. A modulation optical system for providing high contrast modulation of an incident light beam, comprising:

(a) a wire grid polarization beamsplitter with a substrate having a surface;

(i) an array of parallel, elongated, composite wires disposed on said surface, wherein each of said composite wires are spaced apart at a grid period less than a wavelength of said incident light;

(ii) wherein each of said composite wires comprises an intra-wire substructure of alternating elongated metal wires and elongated dielectric layers;

(iii) wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers comprises at least two of said elongated metal wires; and

wherein said wire grid polarization beamsplitter transmits a first polarization state of said light beam and reflects a second polarization state of said light beam, wherein said second polarization state is orthogonal to said first polarization state;

(b) a reflective spatial light modulator having a plurality of individual elements which alter said first polarization state of said transmitted light beam to provide an image bearing beam; and

(c) wherein said image bearing beam reflects from said wire grid polarization beamsplitter.

14. A modulation optical system according claim 13 which includes a polarization analyzer which transmits said image bearing light beam and attenuates unwanted polarization components of said image bearing light beam.

15. A modulation optical system according to claim 13 which includes a pre-polarizer for pre-polarizing said beam of light.

16. A modulation optical system according to claim 13 wherein said spatial light modulator is a liquid crystal display device.

17. A modulation optical system according to claim 13 wherein said composite wires on said wire grid polarization beamsplitter face said reflective spatial light modulator.

18. A modulation optical system for providing high contrast modulation of an incident light beam, comprising:

(a) a wire grid polarization beamsplitter with a substrate having a surface;

(i) an array of parallel, elongated, composite wires disposed on said surface, wherein each of said composite wires are spaced apart at a grid period less than a wavelength of said incident light;

(ii) wherein each of said composite wires comprises an intra-wire substructure of alternating elongated metal wires and elongated dielectric layers;

(iii) wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers comprises at least two of said elongated metal wires;

wherein said wire grid polarization beamsplitter reflects a first polarization state of said light beam and transmits a second polarization state of said light beam, wherein said second polarization state is orthogonal to said first polarization state;

(b) a reflective spatial light modulator having a plurality of individual elements which alter said first polarization state of said reflected light beam to provide an image bearing beam; and

(c) wherein said image bearing beam is transmitted through said wire grid polarization beamsplitter.

19. A modulation optical system according claim 18 which includes a polarization analyzer which transmits said image bearing light beam and attenuates unwanted polarization components of said image bearing light beam.

20. A modulation optical system according to claim 18 which includes a pre-polarizer for pre-polarizing said beam of light.

21. A modulation optical system according to claim 18 wherein said spatial light modulator is a liquid crystal display device.

22. A modulation optical system according to claim 18 wherein said composite wires on said wire grid polarization beamsplitter face said reflective spatial light modulator.

23. A modulation optical system for providing high contrast modulation of an incident light beam, comprising:

(a) a wire grid polarization beamsplitter with a substrate having a surface;

(i) an array of parallel, elongated, composite wires disposed on said surface, wherein each of said composite wires are spaced apart at a grid period less than a wavelength of said incident light;

(ii) wherein each of said composite wires comprises an intra-wire substructure of alternating elongated metal wires and elongated dielectric layers;

(iii) wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers comprises at least two of said elongated metal wires;

wherein said wire grid polarization beamsplitter reflects a first polarization state of said light beam and transmits a second polarization state of said light beam, wherein said second polarization state is orthogonal to said first polarization state;

(b) a first reflective spatial light modulator having a plurality of individual elements which alter said first polarization state of said reflected light beam to provide an image bearing beam, where said image bearing beam is subsequently transmitted through said wire grid polarization beamsplitter; and

(c) a second reflective spatial light modulator having a plurality of individual elements which alter said second polarization state of said transmitted light beam to provide a second image bearing beam, where said second image bearing beam is subsequently reflected off said wire grid polarization beamsplitter.

24. A modulation optical system according claim 23 which includes a polarization analyzer which transmits said first and second image bearing light beams and attenuates unwanted polarization components of said image bearing light beams.

25. A modulation optical system according to claim 23 which includes a pre-polarizer for pre-polarizing said beam of light.

26. A modulation optical system according to claim 23 wherein said first and second spatial light modulators are liquid crystal display devices.

27. A modulation optical system for providing high contrast modulation of an incident light beam, comprising:

(a) a wire grid polarizer with a substrate having a surface;

(i) an array of parallel, elongated, composite wires disposed on said surface, wherein each of said composite wires are spaced apart at a grid period less than a wavelength of said incident light;

(ii) wherein each of said composite wires comprises an intra-wire substructure of alternating elongated metal wires and elongated dielectric layers;

(iii) wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers comprises at least two of said elongated metal wires;

wherein said wire grid polarizer reflects a first polarization state of said light beam and transmits a second polarization state of said light beam, wherein said second polarization state is orthogonal to said first polarization state;

(b) a spatial light modulator having a plurality of individual elements which alters said second polarization state of said light beam to provide an image bearing beam;

(c) at least one additional polarizer to enhance the polarization contrast ratio of said image bearing beam; and

wherein said spatial light modulator is located in an optical path traversed by said light beam such that it is between said wire grid polarizer and said additional polarizer.

28. A wire grid polarizer for polarizing an incident light beam comprising:

a substrate having a surface;

an array of parallel, elongated, composite wires with intervening grooves disposed on said surface, wherein each of said composite wires are spaced apart at a grid period;

wherein each of said composite wires comprises an intra-wire substructure of alternating elongated metal wires and elongated dielectric layers; and

wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers comprises at least two of said elongated metal wires.

29. A wire grid polarizer as in claim 28 wherein each of said grooves are filled with a dielectric optical material.

30. A wire grid polarizer as in claim 29 wherein said dielectric optical material is selected from a group comprised of an optically clear liquid, adhesive, and gel.

31. A wire grid polarizer as in claim 29 wherein said dielectric optical material has an index of refraction which is the same as the index of refraction of said elongated dielectric layers.

32. A wire grid polarizer as in claim 28 wherein said wire grid polarizer is oriented at an angle relative to said incident light beam.

33. A wire grid polarizer as in claim 28 wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers provide resonance enhanced tunneling through said elongated metal wires.

34. A wire grid polarizer as in claim 33 wherein one of said dielectric layers is adjacent to said surface of said substrate.

35. A wire grid polarizer as in claim 33 wherein one of said dielectric layers forms a top layer of said intra-wire substructure.

36. A wire grid polarizer as in claim 33 wherein at least one of said dielectric layers has a thickness different from each of said other dielectric layers.

37. A wire grid polarizer as in claim 33 wherein at least one of said dielectric layers has a different refractive index than said other dielectric layers.

38. A wire grid polarizer as in claim 28 wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers comprises at least one of said dielectric layers.

39. A wire grid polarizer as in claim 28 wherein said intra-wire substructure of alternating elongated metal wires and elongated dielectric layers comprise a plurality of said dielectric layers.

40. A wire grid polarizer as in claim 28 wherein one of said elongated metal wires is adjacent to said surface of said substrate.

41. A wire grid polarizer as in claim 28 wherein one of said elongated metal wires forms a top surface of said intra-wire substructure.

42. A wire grid polarizer as in claim 28 wherein said elongated dielectric layers are thicker than said elongated metal wires.

43. A wire grid polarizer as in claim 28 wherein a thickness of said composite wire is between one-half to five wavelengths of said incident light.

44. A wire grid polarizer as in claim 28 wherein said elongated metal wires have a thickness between 1-4 skin depth thicknesses.

45. A wire grid polarizer as in claim 28 wherein said elongated metal wires are selected from a group comprising aluminum, gold, and silver.

46. A wire grid polarizer as in claim 28 wherein said elongated dielectric layers are selected from a group comprising MgF2, SiO2, and TiO2.

47. A wire grid polarizer as in claim 28 wherein a thickness of said composite wires varies across the surface of said substrate.