Wire grid polarizer with dual absorptive regions

Patent metadata

Field	Value
Publication number	US-9869898-B2
Application number	US-201715458715-A
Country	US
Kind code	B2
Filing date	Mar 14, 2017
Priority date	Jun 25, 2014
Publication date	Jan 16, 2018
Grant date	Jan 16, 2018

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 disposed on an opposite side of the LCD from the incoming wire grid polarizer, the analyzer wire grid polarizer comprising:
i) a transparent substrate which is different from the transparent substrate of the incoming wire grid polarizer;
ii) an array of parallel, elongated rods, which are different from the array of parallel, elongated rods of the incoming wire grid polarizer, disposed over a surface of a transparent substrate of the analyzer wire grid polarizer;
iii) gaps between adjacent rods of the analyzer wire grid polarizer, each of the rods of the analyzer wire grid polarizer including a reflective wire sandwiched between two absorptive ribs; 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 material of the reflective wire is capable of reflecting greater than 80% of light in the visible region of the electromagnetic spectrum.

4. The image projection system of claim 1 , wherein material of the two absorptive ribs are capable of absorbing more than 40% of light in the visible region of the electromagnetic spectrum.

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 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.

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

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

11. 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.

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

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

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

15. 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; and the wires having a thickness of between 140-220 nanometers, the ribs have a thickness of between 10-30 nanometers, or both.

16. The wire grid polarizer of claim 15 , wherein in each rod, the ribs adjoin the wire.

17. The wire grid polarizer of claim 15 , wherein the ribs comprise germanium.

18. The wire grid polarizer of claim 15 , wherein the rods have a pitch of between 40-160 nanometers.

19. The wire grid polarizer of claim 15 , wherein the gaps are filled with a dielectric material.

20. The wire grid polarizer of claim 15 , wherein: the two absorptive ribs include bottom rib closest to the substrate and a top rib farthest from the substrate; and the gaps extend from a base of the bottom rib to a top of the top rib.

Assignees

• Moxtek Inc

Inventors

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

Classifications

• G02F1/133555

  Transflectors · CPC title

• G02F1/13362 Primary

  providing polarized light, e.g. by converting a polarisation component into another one · CPC title

• G02B5/3058 Primary

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

• G02F2001/133548

  Physics · mapped topic

• G03B21/006

  using LCD's · CPC title