Patent ID: 6072558
Filing Date: 2000-06-06
Classification: G02F,G09G

Abstract:
A liquid crystal electrooptical element, comprising:first and second opposing substrates;a group of substantially parallel electrodes disposed on an interior major surface of each of said first and second substrates, wherein said electrodes define a plurality of pixel areas and at least one non-pixel area between adjacent pixel areas;first and second alignment films formed respectively on said electrode groups of said first and second substrates having first and second alignment directions;first and second polarizers disposed relative to an exterior major surface of each of said first and second substrates; anda liquid crystal medium interposing said electrode groups of said first and second substrates having a helical pitch p.sub.o, a difference (.DELTA.n) in refractive indices of said liquid crystal medium and exhibiting a twisted structure in an initial state with an initial twist angle of approximately .phi..sub.r, said liquid crystal medium relaxable to a first metastable state having a twist angle of approximately .phi..sub.r +180.degree. and a second metastable state having a twist angle of approximately .phi..sub.r -180.degree.;wherein a ratio of a layer thickness d of said liquid crystal medium in said pixel areas to the helical pitch of said liquid crystal medium is within the range 0.8(.phi..sub.r)/360.degree..ltoreq.d/p.sub.o .ltoreq.1.4 (.phi..sub.r)/360.degree.;wherein polarization axes angles P, A of said first and second polarizers relative to one of the first and second alignment directions are set based on the layer thickness d, the difference (.DELTA.n) in refractive indices of said liquid crystal medium, the initial twist angle, the twist angle of said first metastable state, and the twist angle of said second metastable state, so that one of said first and second metastable states comprises an ON display state and the other of said first and second metastable states comprises an OFF display state; andwherein a layer thickness d.sub.o of said liquid crystal medium in said at least one non-pixel area is greater than said thickness d.