UV modification of surface pretilt of alignment layers for multidomain liquid crystal displays

Two types of ultraviolet (UV) light induced modification of the surface pretilt of alignment layers are reported. The UV modification allows the liquid crystal (LC) surface pretilt angle of a polyimide film to be selectively altered in a small area. Two device structures for fabricating two-domain liquid crystal displays based on this selective alteration of the LC surface pretilt angle of polyimides are proposed. Results from 3D simulation show that each pixel splits into two domains for the proposed structures. Experimentally, two-domain twisted nematic (TN) test panels and thin-film-transistor (TFT) addressed two-domain TN panels were fabricated using this method. The UV modification described in this letter does not require conventional photoresist technology as do other methods of fabricating two domain liquid crystal displays (LCDs). This process is simple as it requires only one polyimide coating and one rubbing step for each substrate. © 1995 American Institute of Physics.