Small-Pitch Wire Grid Polarizer

Patent metadata

Field	Value
Publication number	US-2017059758-A1
Application number	US-201615195602-A
Country	US
Kind code	A1
Filing date	Jun 28, 2016
Priority date	Aug 24, 2015
Publication date	Mar 2, 2017
Grant date	—

Abstract

The wire grid polarizer (WGP) comprises an array of parallel, elongated nanostructures located over a surface of a transparent substrate and a plurality of spaces, including a space between adjacent nanostructures. Each of the nanostructures can include (1) a plurality of parallel, elongated wires located on the substrate, including an inner-pair located between an outer-pair; (2) lateral-gaps between each wire of the outer-pair and an adjacent wire of the inner-pair; (3) and a center-gap between the two wires of the inner-pair.

First claim

What is claimed is:

1 . A wire grid polarizer (WGP) comprising:
a. an array of parallel, elongated nanostructures located over a surface of a transparent substrate, each of the nanostructures including:
i. an elongated base-rib located over the substrate and having a distal-surface located away from the substrate;
ii. a plurality of parallel, elongated wires located on the distal-surface of the base-rib, including an inner-pair located between an outer-pair, wherein the wires are laterally oriented and spaced apart with respect to one another and each wire has a proximal-end closer to the substrate and a distal-end farther from the substrate and a thickness defined as a distance from the proximal-end to the distal-end;
iii. lateral-gaps between each wire of the outer-pair and an adjacent wire of the inner-pair, wherein each lateral-gap includes a lateral-solid-material-free-region extending from the distal-end towards the proximal-end for a distance of at least 25% of the thickness of a wire of the inner-pair, adjacent to the lateral-gap; and
iv. a center-gap between the wires of the inner-pair, wherein the center-gap includes a center-solid-material-free-region extending from the distal-end towards the proximal-end for a distance of at least 25% of the thickness of one of the wires of the inner-pair; and
b. a plurality of spaces, including a space between adjacent nanostructures, wherein each space includes an inter-nanostructure solid-material-free-region extending from the distal-end to the proximal-end, and beyond the proximal-end for a distance of at least 25% of the thickness of at least one of the wires of the outer-pair that adjoins the space.

2 . The WGP of claim 1 , wherein:
a. each of the nanostructures further includes an array of parallel, elongated rods, including a rod associated with each wire; b. each rod is located between the substrate and the wire it is associated with; and c. the rods are separated from each other by the lateral-solid-material-free-regions, the center-solid-material-free-regions, and the inter-nanostructure solid-material-free-regions.

3 . The WGP of claim 1 , wherein:
a. the lateral-solid-material-free-region extends from the distal-end towards the proximal-end for a distance of between 70% and 98% of the thickness of a wire of the inner-pair, adjacent to the lateral-gap; and b. the center-solid-material-free-region extends from the distal-end towards the proximal-end for a distance of between 70% and 98% of the thickness of at least one of the wires of the inner-pair.

4 . The WGP of claim 1 , wherein the center-solid-material-free-region extends from the distal-end to the proximal-end, and beyond the proximal-end for a distance of at least 10% of the thickness of at least one of the wires of the inner-pair.

5 . The WGP of claim 1 , further comprising a support-rib between the two wires of the inner-pair, wherein the support-rib extends between 5% and 75% of a distance from the proximal-end towards the distal-end of at least one of the wires of the inner-pair.

6 . The WGP of claim 1 , wherein:
a. the plurality of parallel, elongated wires also include a middle-pair; b. the wires of each middle-pair are laterally oriented with respect to one another, to the inner-pair, and to the outer-pair; c. each wire of the middle-pair
i. is located between a wire of the inner-pair and a wire of the outer-pair;
ii. is separated from the other wire of the middle-pair by wires of the inner-pair and by the center-gap; and
iii. extends between 5% and 75% of a distance from the proximal-end towards the distal-end of at least one of the wires of the inner-pair, adjacent to the middle-pair.

7 . The WGP of claim 6 , wherein at least one of the following is reflective and at least one of the following is absorptive: the inner-pair, the middle-pair, and the outer-pair.

8 . The WGP of claim 1 , wherein a chemical composition of the inner-pair is different from a chemical composition of the outer-pair,

9 . The WGP of claim 1 , wherein widths of the lateral-gaps, the center-gap, and the space all differ from one another

10 . The WGP of claim 1 , wherein:
a. the plurality of parallel, elongated wires also include a second-outer-pair; b. wires of the second-outer-pair are laterally oriented with respect to one another, to the inner-pair, and to the outer-pair; c. wires of the second-outer-pair are located to sandwich the inner-pair and the outer-pair; and d. each wire of the second-outer-pair is separated from the other wire of the second-outer-pair by wires of the outer-pair, wires of the inner-pair, and the center-gap.

11 . A wire grid polarizer (WGP) comprising:
a. an array of parallel, elongated nanostructures located over a surface of a transparent substrate, each of the nanostructures including:
i. a plurality of parallel, elongated wires located on the substrate, including an inner-pair located between an outer-pair, wherein the wires are laterally oriented and spaced apart with respect to one another and each wire has a proximal-end closer to the substrate and a distal-end farther from the substrate and a thickness defined as a distance from the proximal-end to the distal-end;
ii. lateral-gaps between each wire of the outer-pair and an adjacent wire of the inner-pair, wherein each lateral-gap includes a lateral-solid-material-free-region extending from the distal-end towards the proximal-end for a distance of at least 25% of the thickness of a wire of at least one of the inner-pair, adjacent to the lateral-gap; and
iii. a center-gap between the wires of the inner-pair, wherein the center-gap includes a center-solid-material-free-region extending from the distal-end towards the proximal-end for a distance of at least 25% of the thickness of at least one of the wires of the inner-pair;
b. a plurality of spaces, including a space between adjacent nanostructures, wherein each space includes an inter-nanostructure solid-material-free-region extending from the distal-end towards the proximal-end for a distance of at least at least 25% of the thickness of at least one of the wires of the outer-pair that adjoins the space; and c. widths of the lateral-gaps, the center-gap, and the space all being different from one another.

12 . The WGP of claim 11 , wherein widths of the lateral-gaps, the center-gap, and the space all differ from one another by at least 5 nanometers.

13 . The WGP of claim 11 , wherein a largest width of the lateral-gaps, the center-gap, and the space differ from a smallest width of the lateral-gaps, the center-gap, and the space by at least 50% of the smallest width.

14 . The WGP of claim 11 , wherein widths of the lateral-gaps are smaller than the width of the center-gap and smaller than the width of the space.

15 . A method of making a wire grid polarizer (VVGP), the method comprising the following steps in order:
a. providing an array of parallel, elongated support ribs located over a transparent substrate and spaces between the support ribs, the spaces being solid-material-free; b. conformal coating the substrate and the support ribs with a first-layer while maintaining solid-material-free at least a portion of the spaces between the support ribs, c. etching the first-layer to remove horizontal segments and leaving an array of inner-pairs of parallel, elongated wires along sides of the support ribs, each wire of each inner-pair being separate from the other wire of the inner-pair; d. conformal coating the substrate and the support ribs with a second-layer while maintaining solid-material-free at least a portion of the

Assignees

• Moxtek Inc

Inventors

• Wang Bin
• Li Hua
• Bowers Brian

Classifications

• G02B5/00

  Optical elements other than lenses (light guides G02B6/00; optical logic elements G02F3/00) · CPC title

• G02B17/00

  Systems with reflecting surfaces, with or without refracting elements · CPC title

• G02B26/00

  Optical devices or arrangements for the control of light using movable or deformable optical elements (control of light by modification of the optical properties of the media of the elements involved therein G02F1/00) · CPC title

• G02B6/136

  by etching · CPC title

• G02B5/1857

  using exposure or etching means, e.g. holography, photolithography, exposure to electron or ion beams · CPC title