Wire grid polarizer with dual absorptive regions

Patent metadata

Field	Value
Publication number	US-2016357064-A1
Application number	US-201514731948-A
Country	US
Kind code	A1
Filing date	Jun 5, 2015
Priority date	Jun 25, 2014
Publication date	Dec 8, 2016
Grant date	—

Abstract

A selectively-absorptive wire grid polarizer comprising an array of parallel, elongated rods disposed over a surface of a transparent substrate with gaps between adjacent rods, each of the rods including a reflective wire sandwiched between two absorptive ribs. A method of making this wire grid polarizer. A use of this wire grid polarizer in an image projection system.

First claim

What is claimed is:

1 . An image projection system comprising:
a. an incoming wire grid polarizer disposed between a light source and a liquid crystal display (LCD); b. the incoming wire grid polarizer including an array of parallel, elongated rods disposed over a surface of a transparent substrate with gaps between adjacent rods, each of the rods including a reflective wire sandwiched between two absorptive ribs; c. the incoming wire grid polarizer disposed in a location to receive light from the light source and capable of substantially transmitting one polarization and substantially absorbing an opposite polarization of the light from the light source; and d. the incoming wire grid polarizer disposed in a location to receive reflected light from the LCD and capable of substantially absorbing the reflected light from the LCD.

2 . The image projection system of claim 1 , further comprising:
a. an analyzer wire grid polarizer:
i. comprising an array of parallel, elongated rods disposed over a surface of a transparent substrate with gaps between adjacent rods, each of the rods including a reflective wire sandwiched between two absorptive ribs; and
ii. disposed on an opposite side of the LCD from the incoming wire grid polarizer; and
b. an X-Cube disposed on an opposite side of the analyzer wire grid polarizer from the LCD.

3 . The image projection system of claim 1 , wherein the polarizer, in the light wavelength range of 450 nanometers through 700 nanometers, is capable of:
a. absorbing at least 80% of one polarization of light from both sides of the polarizer; and b. transmitting at least 80% of an opposite polarization of light.

4 . The image projection system of claim 1 , wherein:
a. the ribs are capable of absorbing greater than 40% and reflecting less than 60% of one polarization of light in the wavelength range of 450 nanometers through 700 nanometers; b. the wires are capable of reflecting greater than 80% and absorbing less than 20% of one polarization of light in the wavelength range of 450 nanometers through 700 nanometers.

5 . The image projection system of claim 1 , wherein the ribs comprise a mass percent of at least 80% silicon, at least 80% titanium, or at least 80% tantalum.

6 . The image projection system of claim 1 , wherein at least one of the ribs adjoins the wire in each rod.

7 . A selectively-absorptive wire grid polarizer comprising an array of parallel, elongated rods disposed over a surface of a transparent substrate with gaps between adjacent rods, each of the rods including a reflective wire sandwiched between two absorptive ribs.

8 . The wire grid polarizer of claim 7 , wherein the polarizer, in the light wavelength range of 450 nanometers through 700 nanometers, is capable of:
a. absorbing at least 80% of one polarization of light from both sides of the polarizer; and b. transmitting at least 80% of an opposite polarization of light.

9 . The wire grid polarizer of claim 7 , wherein:
a. the ribs are capable of absorbing greater than 40% and reflecting less than 60% of one polarization of light in the wavelength range of 450 nanometers through 700 nanometers; b. the wires are capable of reflecting greater than 80% and absorbing less than 20% of one polarization of light in the wavelength range of 450 nanometers through 700 nanometers.

10 . The wire grid polarizer of claim 7 , wherein the rods are formed by etching to form the ribs and the wires.

11 . The wire grid polarizer of claim 7 , wherein the ribs comprise silicon, titanium, tantalum, or combinations thereof.

12 . The wire grid polarizer of claim 7 , wherein the ribs comprise a mass percent of at least 80% silicon, at least 80% titanium, or at least 80% tantalum.

13 . The wire grid polarizer of claim 7 , wherein the wires are metallic.

14 . The wire grid polarizer of claim 7 , wherein at least one of the ribs adjoins the wire in each rod.

15 . The wire grid polarizer of claim 7 , wherein both ribs adjoin the wire on opposite sides thereof in each rod.

16 . A method of making a selectively-absorptive wire grid polarizer, the method comprising:
a. depositing a layer of absorptive material (first layer) over a surface of a transparent substrate; b. depositing a layer of reflective material (second layer) over a surface of the first layer; c. depositing a layer of absorptive material (third layer) over a surface of a the second layer; and d. etching the three layers to form separate rods, the rods capable of:
i. substantially transmitting one polarization of light; and
ii. substantially absorbing an opposite polarization of light incident on the polarizer from either of two opposite directions.

17 . The method of claim 16 , wherein the polarizer, in the light wavelength range of 450 nanometers through 700 nanometers, is capable of:
a. absorbing at least 80% of one polarization of light from both sides of the polarizer; and b. transmitting at least 80% of an opposite polarization of light.

18 . The method of claim 16 , wherein:
a. the ribs are capable of absorbing greater than 40% and reflecting less than 60% of one polarization of light in the wavelength range of 450 nanometers through 700 nanometers; b. the wires are capable of reflecting greater than 80% and absorbing less than 20% of one polarization of light in the wavelength range of 450 nanometers through 700 nanometers.

19 . The method of claim 16 , wherein at least one of the ribs adjoins the wire in each rod.

20 . The method of claim 16 , wherein both ribs adjoin the wire on opposite sides thereof in each rod.

Assignees

• Moxtek Inc

Inventors

• Nielson R Stewart
• Williams Bradley R
• Downard Benjamin
• Willamson D Brent

Classifications

• G02F1/133536 Primary

  Reflective polarizers (G02F1/13362 takes precedence) · CPC title

• G02B5/3058 Primary

  comprising electrically conductive elements, e.g. wire grids, conductive particles · CPC title

• G02F2001/133548

  Physics · mapped topic

• G02B27/149

  using crossed beamsplitting surfaces, e.g. cross-dichroic cubes or X-cubes · CPC title

• G03B21/006

  using LCD's · CPC title