Method and apparatus for correcting a visible light beam using a wire-grid polarizer

• US 7,375,887 B2
• Filed: 11/24/2004
• Issued: 05/20/2008
• Est. Priority Date: 03/27/2001
• Status: Expired due to Fees

• Current Assignee: Moxtek (Polatechno Co.,Ltd.)
• Original Assignee: Moxtek (Polatechno Co.,Ltd.)
• Inventors: Thorne, Jim, Gardner, Eric, Hansen, Douglas P., Perkins, Raymond
• Primary Examiner(s): LAVARIAS, ARNEL C
• Application Number:
  US10/997,077
• Publication Number:
  US 20050146720A1
• Time in Patent Office: 1,273 Days
• Field of Search: 359/486, 359/489
• US Class Current: 359/485.05
• CPC Class Codes: G02B 27/288 Filters employing polarising elements, e.g. Lyot or Solc filters G02B5/3016 takes precedence
• CPC Class Codes: G02B 5/3058 comprising electrically conductive elements, e.g. wire grids, conductive particles

Abstract

An optical system and method for providing a visible light beam with a desired characteristic includes a visible light source producing a visible light beam defining an optical train. An optical element is disposed in the optical train to create a modified beam, and that is capable of introducing an undesired characteristic that continuously transitions across at least a portion of the modified beam. A wire-grid polarizer is disposed in the optical train, and has a plurality of elongated elements with at least a portion that continuously transitions to a different characteristic. The wire-grid polarizer is positioned and oriented in the optical train with the different characteristic corresponding to the undesired characteristic of the modified beam to obtain a visible light beam with a desired characteristic substantially across the visible light beam.

Claims

1. A method for obtaining a visible light beam with a desired characteristic, comprising the steps of:

a) providing a visible light beam;

b) modifying the visible light beam with an optical element to obtain a modified beam, the optical element being capable of introducing an undesired characteristic that continuously transitions across at least a portion of the modified beam; and

c) compensating for the undesired characteristic of the modified beam with a wire-grid polarizer having a plurality of elongated elements with at least a portion that continuously transitions to a different characteristic corresponding to the undesired characteristic of the modified beam to obtain a visible light beam with a desired characteristic substantially across the visible light beam.

2. A method in accordance with claim 1, wherein the step of modifying further includes modifying the visible light beam with an optical element having an undesirable characteristic;

and wherein the step of compensating further includes compensating for the undesirable characteristic of the optical element.

3. A method in accordance with claim 1, wherein the undesired characteristic of the modified beam includes an undesirable, continuous transition in polarization state;

and wherein the plurality of elongated elements have at least a portion that continuously transitions to a different characteristic corresponding to the undesirable, continuous transition in polarization state of the modified beam to obtain a visible light beam with a substantially uniform polarization state.

4. A method in accordance with claim 1, wherein the step of compensating further comprises the step of disposing a wire-grid polarizer with a plurality of elongated elements that continuously transition to a different characteristic selected from the group consisting of:

a different angular orientation;

a different period;

a different width;

a different thickness;

a different shape; and

a curvature.

5. A method in accordance with claim 1, wherein the step of modifying further comprises the step of disposing an optical element in the visible light beam, the optical element being selected from the group consisting of:

a lens;

a transmissive liquid crystal array;

a reflective liquid crystal array;

an optical retarder;

a waveplate;

a prism;

a substrate;

a mirror;

a concave mirror;

a convex mirror; and

a polarizer.

6. A method in accordance with claim 1, wherein the step of compensating further comprises the step of disposing the wire-grid polarizer in the visible light beam prior to the optical element.

7. A method in accordance with claim 1, wherein the step of compensating further comprises the step of disposing the wire-grid polarizer in the modified light beam subsequent to the optical element.

8. A method in accordance with claim 1, wherein the visible light beam is transmitted through the optical element.

9. A method in accordance with claim 1, wherein the visible light beam is reflected from the optical element.

10. A method in accordance with claim 1, wherein a compensating beam is transmitted through the wire-grid polarizer.

11. A method in accordance with claim 1, wherein a compensating beam is reflected from the wire-grid polarizer.

12. A method in accordance with claim 1, wherein the plurality of elongated elements of the wire-grid polarizer have a period less than a wavelength of visible light and a length greater than the wavelength of visible light.

13. A method for obtaining a visible light beam with a desired polarization state, comprising the steps of:

a) providing a visible light beam;

b) modifying the visible light beam with an optical element to obtain a modified beam, the optical element having an undesirable characteristic capable of introducing an undesirable, continuous transition in polarization state into at least a portion of the modified beam; and

c) compensating for the undesirable characteristic of the optical element and the undesirable, continuous transition in polarization state of the modified beam with a wire-grid polarizer having a plurality of elongated elements with a period less than a wavelength of visible light and a length greater than the wavelength of visible light, the plurality of elongated elements having at least a portion that continuously transitions to a different characteristic corresponding to the undesirable characteristic of the optical element and the undesirable, continuous transition in polarization state of the modified beam to obtain a visible light beam with a substantially uniform polarization state.

14. A method for obtaining a visible light beam with a desired polarization state, comprising the steps of:

a) providing a visible light beam;

b) modifying the visible light beam with an optical element to obtain a modified beam, the optical element having an undesirable characteristic capable of introducing an undesirable polarization into at least a portion of the modified beam; and

c) compensating for the undesirable characteristic of the optical element and the undesirable polarization of the modified beam with a wire-grid polarizer having a plurality of elongated elements with at least a portion that continuously transitions to a different characteristic corresponding to the undesirable characteristic of the optical element and the undesirable polarization of the modified beam to obtain a visible light beam with a substantially uniform polarization state.

15. A method for treating a beam to compensate for an undesired optical effect applied by an optical element, comprising the steps of:

a) providing an optical train defined by a beam;

b) providing an optical element in the optical train, the optical element including a modifying portion capable of undesirably modifying at least a portion of the beam to transition from a desired polarization to a different, undesired polarization;

c) providing a wire-grid polarizer in the optical train having a plurality of elongated elements with at least a portion that continuously transition to a different characteristic corresponding to the modifying portion of the optical element and the transition from the desired polarization to the different, undesired polarization; and

d) positioning the wire-grid polarizer so that the continuous transition to a different characteristic corresponds to the transition from the desired polarization to the different, undesired polarization.

16. An optical system configured to provide a visible light beam with a desired characteristic, comprising:

a) a visible light source producing a visible light beam defining an optical train;

b) an optical element, disposed in the optical train to create a modified beam, capable of introducing an undesired characteristic that continuously transitions across at least a portion of the modified beam; and

c) a wire-grid polarizer, disposed in the optical train, having a plurality of elongated elements with at least a portion that continuously transitions to a different characteristic, the wire-grid polarizer being positioned and oriented in the optical train with the different characteristic corresponding to the undesired characteristic of the modified beam to obtain a visible light beam with a desired characteristic substantially across the visible light beam.

17. A system in accordance with claim 16, wherein the optical element has an undesirable characteristic;

and wherein the wire-grid polarizer is positioned and oriented with respect to the optical element with the different characteristic corresponding to the undesirable characteristic of the optical element.

18. A system in accordance with claim 16, wherein the undesired characteristic of the modified beam includes an undesirable, continuous transition in polarization state;

and wherein the plurality of elongated elements have at least a portion that continuously transitions to a different characteristic corresponding to the undesirable, continuous transition in polarization state of the modified beam to obtain a visible light beam with a substantially uniform polarization state.

19. A system in accordance with claim 16, wherein the different characteristic is selected from the group consisting of:

a different angular orientation;

a different period;

a different width;

a different thickness;

a different shape; and

a curvature.

20. A system in accordance with claim 16, wherein the optical element is selected from the group consisting of:

a lens;

a transmissive liquid crystal array;

a reflective liquid crystal array;

an optical retarder;

a waveplate;

a prism;

a substrate;

a mirror;

a concave mirror;

a convex mirror; and

a polarizer.

21. A system in accordance with claim 16, wherein the wire-grid polarizer is positioned in the optical train prior to the optical element.

22. A system in accordance with claim 16, wherein the wire-grid polarizer is positioned in the optic train subsequent to the optical element.

23. A system in accordance with claim 16, wherein the optical element transmits the visible light beam through the optical element.

24. A system in accordance with claim 16, wherein the optical element reflects the visible light beam from the optical element.

25. A system in accordance with claim 16, wherein the wire-grid polarizer is positioned to transmit a compensating beam.

26. A system in accordance with claim 16, wherein the wire-grid polarizer is positioned to reflect a compensating beam.

27. A system in accordance with claim 16, wherein the plurality of elongated elements of the wire-grid polarizer have a period less than a wavelength of visible light and a length greater than the wavelength of visible light.

28. An optical system configured to provide a visible light beam with a desired polarization state, comprising:

a) a visible light source producing a visible light beam defining an optical train;

b) an optical element, disposed in the optical train to create a modified beam, having an undesirable characteristic capable of introducing an undesirable, continuous transition in polarization state into at least a portion of the modified beam; and

c) a wire-grid polarizer, disposed in the optical train, having a plurality of elongated elements with at least a portion that continuously transitions to a different characteristic, the wire-grid polarizer being positioned and oriented in the optical train with the different characteristic corresponding to the undesirable characteristic of the optical element and the undesirable, continuous transition in polarization state of the modified beam to obtain a visible light beam with a substantially uniform polarization state.

29. An optical system configured to provide a visible light beam with a desired polarization state, comprising:

a) a visible light source producing a visible light beam defining an optical train;

b) an optical element, disposed in the optical train to create a modified beam, having an undesirable characteristic capable of introducing an undesirable polarization into at least a portion of the modified beam; and

c) a wire-grid polarizer, disposed in the optical train, having a plurality of elongated elements with at least a portion that continuously transitions to a different characteristic, the wire-grid polarizer being positioned and oriented in the optical train with the different characteristic corresponding to the undesirable characteristic of the optical element and the undesirable polarization of the modified beam to obtain a visible light beam with a substantially uniform polarization state.

30. An optical system configured to compensate for an undesired optical effect applied by an optical element, comprising the steps of:

a) a light source producing a beam defining an optical train;

b) an optical element, disposed in the optical train to create a modified beam, having a modifying portion capable of undesirably modifying at least a portion of the beam to transition from a desired polarization to a different, undesired polarization; and

c) a wire-grid polarizer, disposed in the optical train, having a plurality of elongated elements with at least a portion that continuously transitions to a different characteristic, the wire-grid polarizer being positioned and oriented in the optical train with the different characteristic corresponding to the modifying portion of the optical element and the transition from the desired polarization to the different, undesired polarization; and

d) the wire-grid polarizer being positioned so that the continuous transition to a different characteristic corresponds to the transition from the desired polarization to the different, undesired polarization.