Fabrication of nano-scale alignment patterns for liquid crystals to create switchable optical components
A method for fabrication of a nano-scale mold to create a high precision alignment layer for liquid crystals is described. The method comprises forming a nano-scale mold with a negative of a liquid crystal alignment pattern and imprinting a resist material on the mold. The method further comprises performing a set operation on the resist material to cause the resist material to set, the resist material forming a liquid crystal alignment layer. The nano-scale mold is separated from the liquid crystal alignment layer. The method further comprises performing an infiltration operation to cause the liquid crystals to be deposited on the alignment layer, the alignment layer causing the liquid crystals to form the liquid crystal alignment pattern.
1. A device comprising:
a layer of liquid crystals, the layer of liquid crystals aligned according to a liquid crystal alignment pattern;
wherein the liquid crystal alignment pattern is formed by infiltrating liquid crystals into a liquid crystal alignment layer formed via an imprint from a nano-scale mold, and
wherein the nano-scale mold is formed using a double-pattern method to create, in at least one portion of the layer of liquid crystals, a pattern that is under a lithography limit of 10 nm, the double-pattern method comprising:
forming one or more mandrels on a substrate;
depositing a uniform coating on the mandrels and the substrate;
anisotropically etching the uniform coating; and
removing the mandrels from the substrate, the anisotropically etched uniform coating forming the nano-scale mold.
2. The device of claim 1 , further comprising:
a second layer of liquid crystals adhered to the layer of liquid crystals, the second layer of liquid crystals aligned according to a second liquid crystal alignment pattern, the second liquid crystal alignment pattern formed by a second liquid crystal alignment layer.
3. The device of claim 1 , further comprising:
a substrate layer, wherein the layer of liquid crystals is formed on the substrate layer, and
wherein the substrate layer receives input radiation in a direction parallel to the plane of the layer of liquid crystals, the input radiation reflected internally within the substrate layer to exit the substrate layer in a direction orthogonal to the plane of the layer of liquid crystals.
4. The device of claim 1 , further comprising:
a layer of transparent electrodes formed on the layer of liquid crystals, the layer of transparent electrodes, when activated, configured to modify an alignment of the layer of liquid crystals.
5. The device of claim 1 , wherein the formation of the layer of liquid crystals comprises:
forming the nano-scale mold with a negative of the liquid crystal alignment pattern;
imprinting a resist material on the nano-scale mold;
performing a set operation on the resist material to cause the resist material to set, the resist material forming the liquid crystal alignment layer;
separating the nano-scale mold from the liquid crystal alignment layer; and
performing an infiltration operation to cause liquid crystals to be deposited on the liquid crystal alignment layer to form the layer of liquid crystals, the liquid crystal alignment layer causing the liquid crystals to form the liquid crystal alignment pattern.
6. The device of claim 1 , wherein the nano-scale mold comprises a poly-methyl methacrylate material, wherein the nano-scale mold is formed on a silicon substrate, and wherein the nano-scale mold is formed according to an electron beam pattern.
7. The device of claim 1 , wherein the nano-scale mold is non-planar in shape.
8. The device of claim 1 , wherein the formation of the layer of liquid crystals further comprises:
applying anti-adhesion material on the nano-scale mold.
9. The device of claim 1 , wherein the nano-scale mold is a daughter mold formed from a master mold.
10. The device of claim 5 , wherein the resist material is formed on a substrate, the substrate comprising one or more alignment features matching alignment features on the nano-scale mold.
11. The device of claim 5 , wherein the imprinting the resist material causes the nano-scale mold to be applied to the resist material at a certain pressure, temperature, and duration to cause the resist material to fill all voids in the nano-scale mold.
12. The device of claim 5 , wherein the set operation causes the resist material to be exposed to ultraviolet radiation.
13. The device of claim 5 , wherein the resist material is transparent to a range of frequencies of electromagnetic radiation.
14. The device of claim 1 , wherein the liquid crystal alignment pattern includes features under 10 nanometers in length.
15. The device of claim 1 , wherein the liquid crystal alignment pattern causes individual adjacent pixels of a display to be polarized in an alternating pattern.
16. The device of claim 1 , wherein the liquid crystal alignment pattern causes the liquid crystal layer to form a diffraction grating.
17. The device of claim 5 , wherein the formation of the layer of liquid crystals further comprises:
imprinting an additional resist material on the nano-scale mold;
performing the set operation on the additional resist material, the additional resist material forming an additional liquid crystal alignment layer;
separating the nano-scale mold from the additional liquid crystal alignment layer; and
performing the infiltration operation to cause liquid crystals to be deposited on the additional liquid crystal alignment layer.
18. The device of claim 17 , wherein the liquid crystal alignment layer is adhered to the additional liquid crystal alignment layer to form a double alignment layer.
19. The device of claim 18 , wherein the infiltration operation causes the liquid crystals to be deposited via capillary action within the double alignment layer.