Photo-Aligned Liquid Crystal Display Alignment Layer

The patent replaces the mechanical rubbing process with a photo-alignment process. Instead of using a roller covered with cloth to mechanically rub the alignment layer, the invention uses UV irradiation to induce photo-isomerization of azo groups in the polyimide compound, which automatically orients the liquid crystal molecules in the desired direction without mechanical contact, thereby eliminating non-uniform rubbing force issues.

The patent changes the alignment mechanism from mechanical (rubbing) to optical (photo-isomerization). By incorporating azo groups into the polyimide compound and using UV light to trigger photo-isomerization, the alignment process transitions from a mechanical parameter-based approach to an optical parameter-based approach, achieving more uniform and reliable alignment.

The patent applies local quality by incorporating discotic liquid crystal compounds into the alignment layer, which have different optical properties compared to conventional nematic liquid crystals. The discotic liquid crystal molecules provide optical anisotropy that compensates for the refractive anisotropy of the liquid crystal layer, creating localized optical correction that improves image quality specifically in oblique viewing directions while maintaining frontal viewing quality.

The patent uses composite materials by combining polyimide compounds with azo groups and discotic liquid crystal compounds in the alignment layer. This composite structure integrates the mechanical stability of polyimide with the optical properties of azo groups and discotic liquid crystals, creating an alignment layer that provides both structural integrity and optical compensation for widened viewing angles.