Photo-aligning by azo-dyes: Physics and applications 

Liquid crystal photo-alignment using azo-dyes is reviewed. This alignment method is very different from previously reported ones, such as photo-crosslinking, photo degradation and photo-isomerization. It will be shown that this photo-aligning method can provide a controllable pretilt angle and strong anchoring energy of the liquid crystal cell, as well as high thermal and UV stability. The application of this method to the alignment and fabrication of various types of liquid crystal displays is also discussed.