A new technique for creating vertical alignment among liquid crystal modules could allow development of less-costly flexible displays.
Manufacture of the panels is complex, requiring multiple steps that can introduce defects. Among the steps is the application of a polymer film – the so-called alignment layer – to the two pieces of glass between which the liquid crystals operate. The film, which must be rubbed after being coated on the glass, anchors the crystals with a fixed alignment. The process of rubbing to create the necessary alignment can damage some of the transistors and introduce dust, producing defects that can reduce the manufacturing yield of the panels.
By adding side chains to the polymer molecules, researchers at the Georgia Institute of Technology have found a way to eliminate the polymer rubbing step. Instead, they use the in-situ photopolymerization of alkyl acrylate monomers in the presence of nematic liquid crystals to provide a cellular matrix of liquid crystalline droplets in which the chemical structure of the encapsulating polymer controls the liquid crystal alignment..