Photoalignment Agent for Liquid Crystal Displays

The patent replaces the mechanical rubbing method with a photoalignment method. Instead of mechanically rubbing a polymer layer to align liquid crystals, the invention uses light irradiation to induce anisotropy in the polymer layer, achieving alignment without mechanical contact. This eliminates the generation of minute particles and electrostatic discharge while maintaining liquid crystal alignment uniformity.

The patent changes the alignment mechanism from mechanical friction to optical parameter changes. By irradiating polarized light at specific wavelengths (e.g., 254 nm, 365 nm) onto the polymer layer, the light induces molecular anisotropy and orientational order in the polymer chains, which subsequently aligns the liquid crystals. This parameter change from mechanical to optical domain resolves the contradiction between alignment achievement and harmful factor generation.

The patent substitutes the mechanical rubbing process with a photochemical process. The polymer layer is irradiated with ultraviolet or visible light, causing photopolymerization and formation of anisotropic structures that provide both strong layer integrity and uniform liquid crystal alignment. This eliminates the mechanical stress and particle generation that compromise layer strength and cause afterimages.

The patent employs composite polymer materials designed for photoalignment. The polymer layer contains specific functional groups and molecular structures that respond to light irradiation by forming cross-linked or oriented networks. These composite materials provide both mechanical strength for layer stability and optical anisotropy for liquid crystal alignment, simultaneously improving layer strength and reducing afterimages.