Fabrication of an electro-optical cell comprising first and second plates of optically transparent material, comprises processing first and second alignment layers according to the first and second alignment directions respectively

摘要

The process for fabrication of an electro-optical cell comprising a first plate (302) and a second plate (303) of optically transparent material, comprises processing a first alignment layer (304) and a second alignment layer (305) according to the first and second alignment directions respectively, where torsion angle alpha is formed between the first and second directions such that 5[deg] less than alpha less than theta , and theta is an angle associated with liquid crystal molecules (306). The electro-optical cell has a thickness based on liquid crystal molecules between the plates. The process for fabrication of an electro-optical cell comprising a first plate (302) and a second plate (303) of optically transparent material, comprises processing a first alignment layer (304) and a second alignment layer (305) according to the first and second alignment directions respectively, where torsion angle alpha is formed between the first and second directions such that 5[deg] less than alpha less than theta , and theta is an angle associated with liquid crystal molecules (306). The electro-optical cell has a thickness based on liquid crystal molecules between the plates. The first and second alignment layers have anchor energy greater than or equal to a predetermined threshold such that the liquid crystal molecules are located in a common interface between the first and second alignment layer respectively. The material based on the liquid crystal molecules includes ferroelectric liquid crystal material, anti-ferroelectric liquid crystal material, polymer stabilized ferroelectric liquid crystal material, and polymer stabilized anti-ferroelectric liquid crystal material. Each of the first and second alignment layers comprises a photopolymerizable material. The processing of the first and second alignment layers comprises exposing the first alignment layer to UV radiation in a first direction of polarization to form the first direction of alignment, and exposing the second alignment layer to UV radiation in a second direction of polarization to form the second direction of alignment, where the radiation energy is more than 500x 10 -3Jm -2. The processing step is performed by a surface treatment technique with the anchoring energy of greater than 0.33x 10 -3Jm -2. The process further comprises depositing a liquid crystal pre-polymer on one of the first and second alignment layers, radiating the liquid crystal pre-polymer by UV radiation under nitrogen atmosphere, injecting a material based of liquid crystal molecules in the electro-optical cell, and progressively cooling the injected liquid crystal molecules for 2 hours under an electric field of 1 V/mu m at a frequency of 1 kHz. The first and second alignment layers are made of polyimide, and silicon oxide deposited by evaporation to form an angle of 20-25[deg] with the plate along a direction of orientation of liquid crystal molecules. An independent claim is included for an electro-optical cell.