Corrosion resistant wire-grid polarizer and method of fabrication

• US 6,785,050 B2
• Filed: 05/09/2002
• Issued: 08/31/2004
• Est. Priority Date: 05/09/2002
• Status: Active Grant

• Current Assignee: Moxtek (Polatechno Co.,Ltd.)
• Original Assignee: Moxtek (Polatechno Co.,Ltd.)
• Inventors: Perkins, Raymond T., Lines, Michael
• Primary Examiner(s): Robinson, Mark A.
• Assistant Examiner(s): FINEMAN, LEE A
• Application Number:
  US10/143,501
• Publication Number:
  US 20030227678A1
• Time in Patent Office: 845 Days
• Field of Search: 359/486, 359/485, 359/489, 359/352
• US Class Current: 359/485.03
• CPC Class Codes: G02B 5/3058 comprising electrically conductive elements, e.g. wire grids, conductive particles

Abstract

A polarizing device, such as a wire-grid polarizer, includes a substantial mono-layer of a corrosion inhibitor without adversely affecting the optical properties of the polarizing device. The polarizing device can include an optical element and a nano-structure, such as an array of a plurality of spaced-apart, elongated elements disposed on a substrate. The corrosion inhibitor is chemically bonded to surfaces of the elements to form the mono-layer. The mono-layer can have a thickness less than 100 Angstroms. A method of forming the substantial mono-layer can include treating the polarizing device with an amino phosphonate, such as a nitrilotris (methylene) triphosphonic acid.

Claims

1. A corrosion resistant wire grid polarizer device, comprising:

a) a transparent substrate having an optical property of transmitting electromagnetic waves having a wavelength within the range of ultraviolet, visible and infra-red;

b) an array of spaced-apart, elongated elements, disposed on the substrate, sized to interact with electromagnetic waves having a wavelength within the range of ultraviolet, visible and infra-red to generally transmit electromagnetic waves of one polarization, and generally reflect electromagnetic waves of another polarization; and

c) a substantial mono-layer, chemically bonded to the elongated elements without substantially adversely affecting the optical property of the transparent substrate to transmit the electromagnetic waves, and without substantially adversely altering the electromagnetic waves transmitted through the array of spaced-apart, elongated elements and the transparent substrate, the mono-layer being formed from a corrosion inhibitor and having a thickness less than approximately 100 Angstroms.

d) the substantial mono-layer including an amino phosphonate applied to the elongated elements.

2. A device in accordance with claim 1, wherein the elements have a thickness less than approximately 400 nm, a width less than approximately 300 nm, a length greater than approximately 700 nm, and a pitch of less than approximately 400 nm.

3. A device in accordance with claim 1, wherein the amino phosphonate includes a nitrilotris (methylene) triphosphonic acid.

4. A device in accordance with claim 1, wherein the amino phosphonate and the wire grid polarizer device have been heated together to a temperature greater than approximately 150 degrees Celsius.

5. A corrosion resistant wire grid polarizer device for generally decoupling two orthogonal polarizations of electromagnetic waves, the device comprising:

a) an optical element formed from a transparent material to transmit electromagnetic waves having a wavelength within the range of ultraviolet, visible and infra-red;

b) a nano-structure, associated with the optical element, including an array of spaced-apart, elongated elements with a thickness on the order of 10<sup>−

8</sup> m, to interact with the electromagnetic waves having a wavelength within the range of ultraviolet, visible and infra-red to generally transmit electromagnetic waves of one polarization, and generally reflect electromagnetic waves of another polarization; and

c) a corrosion resistant layer, chemically bonded to the nano-structure, having a thickness less than approximately 100 Angstroms, the layer resisting corrosion of the nano-structure without substantially adversely effecting an optical property of the optical element to transmit the electromagnetic waves, and without substantially adversely altering the electromagnetic waves transmitted through the nano-structure and the optical element; and

d) the corrosion resistant layer including an amino phosphonate applied to the elongated elements.

6. A device in accordance with claim 5, wherein the elements have a thickness less than approximately 400 nm, a width less than approximately 300 nm, a length greater than approximately 700 nm, and a pitch of less than approximately 400 nm.

7. A device in accordance with claim 5, wherein the amino phosphonate includes a nitrilotris (methylene) triphosphonic acid.

8. A device in accordance with claim 5, wherein the amino phosphonate and the wire grid polarizer device have been heated together to a temperature greater than approximately 150 degrees Celsius.

9. A method for resisting corrosion of elements of a wire grid polarizer, comprising the steps of:

a) providing a wire grid polarizer having an array of spaced-apart, elongated elements, disposed on a substrate, sized to interact with electromagnetic waves having a wavelength with the range of ultraviolet, visible and infra-red to generally transmit electromagnetic waves of one polarization, and generally reflect electromagnetic waves of another polarization;

b) chemically bonding a corrosion inhibitor to the elongated elements including applying an amino phosphate to at least the elongated elements to form a layer having a thickness less than approximately 100 Angstroms.

10. A method in accordance with claim 9, wherein the step of chemically bonding a corrosion inhibitor to the elongated elements further includes chemically bonding the corrosion inhibitor to all exposed surfaces of the elongated elements.

11. A method in accordance with claim 9, wherein the step of applying the amino phosphonate further includes applying nitrilotris (methylene) triphosphonic acid to at least the elements.

12. A method in accordance with claim 9, further comprising the step of:

heating the wire grid polarizer at a temperature greater than approximately 150 degrees Celsius.

13. A method in accordance with claim 9, wherein the step of applying the amino phosphonate further includes applying a liquid with a solution of 0.0002 liters nitrilotris (methylene) triphosphonic acid per liter of distilled water.

14. A method in accordance with claim 9, wherein the step of applying the amino phosphonate corrosion inhibitor includes dipping the wire grid polarizer in the amino phosphonate corrosion inhibitor at a temperature greater than approximately 70 degree Celsius.

15. A method in accordance with claim 14, further comprising the step of:

rinsing the wire grid polarizer after the amino phosphonate corrosion inhibitor is applied and before drying.

16. A method in accordance with claim 9, wherein the step of chemically bonding a corrosion inhibitor to the elongated elements further including the step of:

altering a natural oxide layer formed on the elongated elements.

17. A corrosion resistant wire grid polarizer device, comprising:

a) a transparent substrate having an optical property of transmitting electromagnetic waves having a wavelength within the range of ultraviolet, visible and infra-red;

b) an array of spaced-apart, elongated elements, disposed on the substrate, sized to interact with electromagnetic waves having a wavelength within the range of ultraviolet, visible and infra-red to generally transmit electromagnetic waves of one polarization, and generally reflect electromagnetic waves of another polarization; and

c) a substantial mono-layer including an amino phosphonate, disposed over the elongated elements without substantially adversely affecting the optical property of the transparent substrate to transmit the electromagnetic waves, and without substantially adversely altering the electromagnetic waves transmitted through the array of spaced-apart, elongated elements and the transparent substrate.

18. A device in accordance with claim 17, wherein the mono-layer has a thickness less than approximately 100 Angstroms.

19. A device in accordance with claim 17, wherein the amino phosphonate includes a nitrilotris (methylene) triphosphonic acid.

20. A device in accordance with claim 17, wherein the amino phosphonate and the wire grid polarizer device have been heated together to a temperature greater than approximately 150 degrees Celsius.

21. A corrosion resistant wire grid polarizer device, comprising:

a) a transparent substrate having an optical property of transmitting electromagnetic waves having a wavelength within the range of ultraviolet, visible and infra-red;

b) an array of spaced-apart, elongated elements, disposed on the substrate, sized to interact with electromagnetic waves having a wavelength within the range of ultraviolet, visible and infra-red to generally transmit electromagnetic waves of one polarization, and generally reflect electromagnetic waves of another polarization;

c) a natural oxide layer, disposed on the elongated elements; and

d) a substantial mono-layer formed from an amino phosphonate, disposed over the natural oxide layer and the elongated elements without substantially adversely affecting the optical property of the transparent substrate to transmit the electromagnetic waves, and without substantially adversely altering the electromagnetic waves transmitted through the array of spaced-apart, elongated elements and the transparent substrate.

22. A device in accordance with claim 21, wherein the mono-layer has a thickness less than approximately 100 Angstroms.

23. A device in accordance with claim 21, wherein the amino phosphonate includes a nitrilotris (methylene) triphosphonic acid.

24. A device in accordance with claim 21, wherein the amino phosphonate and the wire grid polarizer device have been heated together to a temperature greater than approximately 150 degrees Celsius.