Polarizer nanoimprint lithography
A method of making a polarizer can include applying a liquid with solid inorganic nanoparticles dispersed throughout a continuous phase, then forming this into a different phase including a solid, interconnecting network of the inorganic nanoparticles. This method can improve manufacturability and reducing manufacturing cost. This method can be used to provide an antireflective coating, to provide a protective coating on polarization structures, to provide thin films for optical properties, or to form the polarization structures themselves.
1. A method of making a polarizer, the method comprising:
providing polarization structures located on a substrate, the polarization structures arranged in a pattern for polarization of light;
applying an uncured fill layer on top of the polarization structures and extending into channels between the polarization structures, the uncured fill layer being a solution including molecules in a solvent, the solvent including water and an organic liquid, the molecules including metal atoms bonded to reactive groups, where each reactive-group is independently —Cl, —OR 1 , —OCOR 1 , or —N(R 1 ) 2 , and R 1 is an alkyl group;
chemistry of the uncured fill layer and chemistry of a surface of the polarization structures are attractive to each other; and
reacting the molecules to form a solid of the metal atoms interconnected with each other, defining a cured fill layer.
2. The method of claim 1 , wherein the substrate is a first substrate, the method further comprising placing a second substrate onto the uncured fill layer before forming the uncured fill layer into the cured fill layer.
3. The method of claim 1 , wherein the cured fill layer has an index of refraction of ≤1.3.
4. The method of claim 1 , wherein ≥99% of the solid inorganic nanoparticles in the uncured fill layer have a diameter of ≤2 nm.
5. A method of making a polarizer, the method comprising:
providing polarization structures located on a substrate, the polarization structures arranged in a pattern for polarization of light;
applying an uncured fill layer on top of the polarization structures and extending into channels between the polarization structures, the uncured fill layer being a colloidal suspension including a dispersed phase and a continuous phase;
surface energy of a surface of the polarization structures is greater than a surface tension of the uncured fill layer; and
curing the uncured fill layer by removing the continuous phase to form a solid, defining a cured fill layer.
6. The method of claim 5 , wherein the surface energy is five times greater than the surface tension of the uncured fill layer.
7. The method of claim 5 , wherein the substrate is a first substrate, the method further comprising placing a second substrate onto the uncured fill layer before forming the uncured fill layer into the cured fill layer.
8. The method of claim 5 , wherein the cured fill layer has an index of refraction of ≤1.3.
9. A method of making a polarizer, the method comprising:
providing polarization structures located on a substrate, the polarization structures arranged in a pattern for polarization of light;
applying an uncured fill layer on top of the polarization structures and extending into channels between the polarization structures, the uncured fill layer being a liquid with solid inorganic nanoparticles dispersed throughout a continuous phase; and
curing the uncured fill layer to form a cured fill layer, the cured fill layer including a solid, interconnecting network of the inorganic nanoparticles.
10. The method of claim 9 , wherein the substrate is a first substrate, the method further comprising placing a second substrate onto the uncured fill layer before forming the uncured fill layer into the cured fill layer.
11. The method of claim 9 , wherein applying the uncured fill layer and curing the uncured fill layer into the cured fill layer includes the following steps in the following order:
spin coating part of the uncured fill layer onto the polarization device, defining a first spin coat;
baking the polarizer, defining a first bake;
spin coating part of the uncured fill layer onto the polarization device, defining a second spin coat; then
baking the polarizer, defining a second bake.
12. The method of claim 11 , wherein the first spin coat is performed at a speed of ≥1000 rpm and ≤4000 rpm, the first bake is performed at a temperature of ≥50° C. and ≤300° C., the second spin coat is performed at a speed of ≥1000 rpm and ≤4000 rpm, and the second bake is performed at a temperature of ≥50° C. and ≤300° C.
13. The method of claim 9 , wherein the cured fill layer has an index of refraction of ≤1.3.
14. The method of claim 9 , wherein chemistry of the uncured fill layer and chemistry of a surface of the polarization structures are attractive to each other.
15. The method of claim 9 , wherein surface energy of a surface of the polarization structures is greater than a surface tension of the uncured fill layer.
16. The method of claim 9 , wherein the uncured fill layer fills ≥90% of the channels.
17. The method of claim 9 , wherein ≥99% of the solid inorganic nanoparticles in the uncured fill layer have a diameter of ≤2 nm.
18. The method of claim 9 , wherein forming the uncured fill layer into the cured fill layer occurs at a temperature of ≤250° C.
19. The method of claim 9 , wherein the inorganic nanoparticles comprise aluminum oxide.
20. The method of claim 9 , further comprising, before forming the uncured fill layer into the cured fill layer, imprinting a pattern of structures in the uncured fill layer, the structures sized and shaped to reduce reflection of incident light, to increase heat transfer away from the polarizer, or both.