LCD components obtained by patterning of chiral nematic polymer layers

An overview is given of the methods for preparation of birefringent films w ith patterned optical properties and their applications in liquid crystal d isplays. A versatile method of obtaining patterned films is based on manipu lation of the helical twisting power of chiral dopants by photoisomerizatio n reactions. Because of their transparency to visible light, high helical t wisting power and large changes of the helical twisting power during UV irr adiation, menthone derivatives are very suitable dopants for this process. A number of potential applications of the principles are discussed. Pattern ing of chiral nematic films with regions with different twisting angles is a suitable method for the preparation of patterned polarization rotators. P atterning of chiral nematic liquid crystal layers can also be used to contr ol the reflection color and state of polarization of the reflected light. S uch layers are useful for the preparation of reflective color filter arrays and broad band reflective polarizers.