Polarizer having metal grating, its manufacturing method and display device

1. A polarizer, comprising:

a substrate; and

a metal grating formed on the substrate and including a metal nano-wire array arranged in a predetermined direction,

wherein metal nano-wires in the metal nano-wire array are doped in a transparent medium film, and the transparent medium film is made of polyvinyl alcohol (PVA).

2. The polarizer according to claim 1 , wherein a transparent protective film is attached to at least one side of the metal grating, and the transparent protective film is made of triacetate cellulose (TAC) or polymethyl methacrylate (PMMA).

3. The polarizer according to claim 1 , wherein a transparent alignment film having an alignment pattern is coated on the substrate.

4. The polarizer according to claim 3 , wherein the transparent alignment film is made of polyvinyl pyrrolidone (PVP).

5. The polarizer according to claim 3 , wherein the metal nano-wire array is formed on the substrate in accordance with the alignment pattern.

6. The polarizer according to claim 1 , wherein the substrate is a base substrate, an array substrate or a color filter substrate.

7. The polarizer according to claim 1 , wherein the metal nano-wire is made of silver, copper, gold or aluminum nano particles.

8. A display device, comprising the polarizer according to claim 1 .

9. A method for manufacturing a polarizer, comprising steps of:

providing a substrate; and

forming on the substrate a metal grating including a metal nano-wire array arranged in a predetermined direction,

wherein the step of forming on the substrate the metal grating including the metal nano-wire array in the predetermined direction comprises:

coating a transparent medium film doped with metal nano-wires onto the substrate; and

aligning the metal nano-wires in the transparent medium film in the predetermined direction, thereby forming the metal grating including the metal nano-wire array;

wherein the transparent medium film is made of polyvinyl alcohol (PVA).

10. The method according to claim 9 , wherein the step of forming on the substrate the metal grating including the metal nano-wire array arranged in the predetermined direction comprises:

generating metal nano-wires through a chemical growth method;

forming the metal nano-wires on the substrate through spinning or printing; and

aligning on the substrate the metal nano-wires in the predetermined direction, thereby forming the metal grating including the metal nano-wire array arranged in the predetermined direction.

11. The method according to claim 10 , wherein the step of aligning on the substrate the metal nano-wires in the predetermined direction, thereby forming the grating metal including the metal nano-wire array comprises:

curing the metal nano-wires; and

drawing and aligning the cured metal nano-wires, thereby forming the metal grating including the metal nano-wire array.

12. The method according to claim 10 , wherein the step of aligning on the substrate the metal nano-wires in the predetermined direction, thereby forming the grating metal including the metal nano-wire array comprises:

enclosing the metal nano-wires with a polarized organic material;

subjecting the metal nano-wires to induced alignment under an effect of an electric field on the substrate; and

curing the aligned metal nano-wires, thereby forming the metal grating including the metal nano-wire array.

13. The method according to claim 10 , wherein the metal nano-wires are made of silver nano particles, and the step of generating the metal nano-wires through a chemical growth method comprises:

generating the silver nano particles from a silver nitrate solution, with ethylene glycol as a reducing agent; and

forming the metal nano-wires using the silver nano particles, with PVP as an aligning agent and a stabilizer.

14. The method according to claim 9 , wherein the step of forming on the substrate the metal grating including the metal nano-wire array in the predetermined direction comprises:

forming on the substrate a transparent alignment film having an alignment pattern;

generating metal nano-wires on the substrate in accordance with the alignment pattern through a chemical growth method; and

curing the metal nano-wires, thereby forming the metal grating including the metal nano-wire array.

15. The method according to claim 14 , wherein the transparent alignment film is made of polyvinyl pyrrolidone (PVP).

16. The method according to claim 9 , wherein a distance between metal nano-wires in the metal nano-wire array is controlled in accordance with a concentration of nano particles and an ink thickness during printing.