Directed vertical alignment liquid crystal display with fast switching

We describe a directed vertical alignment (VA) display mode based on a nematic liquid crystal (LC) doped with a chiral dopant and confined between two substrates, one of which is pretreated, say, by unidirectional rubbing or photoalignment. The design allows one to eliminate umbilical defects that appear during switching of the conventional VA cells and thus to obtain better contrast. Switching is ∼30% faster than for VA cells when optimized concentration of a chiral dopant is added and LC molecules at one of the substrates are slightly tilted from the cell normal due to the unidirectional surface treatment.