Polarizer with wire pair over rib

• US 9,354,374 B2
• Filed: 08/27/2014
• Issued: 05/31/2016
• Est. Priority Date: 10/24/2013
• Status: Active Grant

• Current Assignee: Moxtek (Polatechno Co.,Ltd.)
• Original Assignee: Moxtek (Polatechno Co.,Ltd.)
• Inventors: Wang, Bin, Wangensteen, Ted, Petrova, Rumyana, Black, Mike, Marks, Steven, Probst, Dean, Davis, Mark Alan
• Primary Examiner(s): Shafer, Ricky D
• Application Number:
  US14/470,498
• Publication Number:
  US 20150116824A1
• Time in Patent Office: 643 Days
• Field of Search: 359/485.05, 359/487.03, 359/900
• US Class Current: 1/1
• CPC Class Codes: C23F 17/00 Multi-step processes for surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by subclass C21D or C22F or class C25 coating for obtaining at least two superposed coatings either by methods not provided for in a single one of main groups C23C2/00 - C23C26/00, or by combinations of methods providedfor in subclasses C23C and C25D, C23C28/00
• CPC Class Codes: G02B 1/08 made of polarising materials
• CPC Class Codes: G02B 1/12 by surface treatment, e.g. by irradiation
• CPC Class Codes: G02B 5/3058 comprising electrically conductive elements, e.g. wire grids, conductive particles

Abstract

Wire grid polarizers, and methods of making wire grid polarizers, including an array of parallel, elongated nano-structures disposed over a surface of a substrate. Each of the nano-structures can include a first rib disposed over a surface of a substrate and a pair of parallel, elongated wires, each laterally oriented with respect to one another, and disposed over the first rib. The wire grid polarizers can be durable with high transmission of one polarization of light, high contrast, and/or small pitch. The wire grid polarizers can also have high absorption or high reflection of an opposite polarization of light.

Claims

1. A wire grid polarizer comprising:

an array of parallel, elongated nano-structures disposed over a surface of a substrate, each of the nano-structures including;

a first rib disposed over the surface of the substrate;

a pair of parallel, elongated wires, each laterally oriented with respect to one another, and disposed over the first rib;

a first gap between the pair of wires; and

each wire of the pair of wires has two opposite sides substantially orthogonal to the surface of the substrate;

a plurality of second gaps including a second gap disposed between adjacent first ribs; and

the substrate being transmissive.

2. The wire grid polarizer of claim 1, further comprising a pair of parallel, elongated side bars, each laterally oriented with respect to one another, including a side bar disposed along and adjoining each side of each wire.

3. The wire grid polarizer of claim 2, wherein:

at least one of the first rib, the pair of wires, or the pair of side bars is absorptive; and

at least one of the first rib, the pair of wires, or the pair of side bars is reflective.

4. The wire grid polarizer of claim 1, further comprising a support rib disposed above the first rib between the pair of wires and extending partially into the first gap.

5. The wire grid polarizer of claim 4, wherein a support rib thickness is between 5% and 35% of a wire thickness.

6. The wire grid polarizer of claim 1, further comprising a pair of parallel, elongated second ribs disposed over the first rib at outer edges of the first rib, wherein each wire of the pair of wires is disposed over a different second rib and the first gap extends from between the pair of wires down between the pair of second ribs.

7. The wire grid polarizer of claim 6, further comprising a pair of parallel, elongated side bars, each laterally oriented with respect to one another, including a side bar disposed along and adjoining each side of each wire and disposed along and adjoining each of two opposite sides of each second rib.

8. The wire grid polarizer of claim 7, wherein:

at least one of the pair of second ribs, the first rib, the pair of wires, or the pair of side bars is absorptive; and

at least one of the pair of second ribs, the first rib, the pair of wires, or the pair of side bars is reflective.

9. The wire grid polarizer of claim 1, wherein the first gaps and the second gaps are solid-material-free gaps.

10. The wire grid polarizer of claim 1, further comprising a fill material disposed in the first gaps and in the second gaps.

11. The wire grid polarizer of claim 10, wherein fill material in a gap is separate from fill material in an adjacent gap.

12. The wire grid polarizer of claim 11, wherein the fill material is absorptive.

13. The wire grid polarizer of claim 1, wherein a first gap width is substantially equal to a second gap width.

14. The wire grid polarizer of claim 1, wherein a larger of a first gap width or a second gap width divided by a smaller of the first gap width or the second gap width is greater than 1.0 and less than or equal to 1.1.

15. The wire grid polarizer of claim 1, wherein a larger of a first gap width or a second gap width divided by a smaller of the first gap width or the second gap width is greater than or equal to 1.1 and less than or equal to 1.5.

16. A method of making a wire grid polarizer, the method comprising the following steps in order:

providing a substrate having an array of parallel, elongated support ribs disposed over the substrate with solid-material-free support-rib gaps between the support ribs, the substrate being substantially transmissive to incoming light;

conformal coating the substrate and the support ribs with a layer of material while maintaining the support-rib gaps between the support ribs;

etching the layer of material to remove horizontal segments and leaving an array of parallel, elongated wires along sides of the support ribs, including a pair of wires for each support rib with a wire disposed along each side of the support rib; and

using the wires as a mask and etching the support ribs between two wires of the pair of wires and etching the substrate between adjacent pairs of wires forming;

an array of parallel elongated first ribs, with each pair of wires disposed over a single first rib;

a first gap between the pair of wires; and

a plurality of second gaps including a second gap disposed between adjacent first ribs.

17. The method of claim 16, wherein etching the support ribs includes etching only part of the support ribs such that a portion of the support ribs remains in the first gaps between the wires.

18. The method of claim 16, wherein etching the support ribs includes etching away the entire support ribs and stopping the etch between the pair of wires substantially at a base of the wires and at a top of the first ribs.

19. The method of claim 16, wherein etching the support ribs includes substantially etching away the entire support ribs and then etching into the first ribs between two wires of each pair of wires forming a pair of parallel, elongated second ribs disposed over and at outer edges of each of the first ribs with a wire disposed over each second rib.

20. The method of claim 16, further comprising:

conformal coating the wires, the first ribs, and exposed portions of the substrate with a second layer of material while maintaining the first gap between the pair of wires and the second gaps between adjacent first ribs;

etching the second layer of material to remove horizontal segments and leaving an array of parallel, elongated side bars.