Black-white liquid crystal display having an insulation layer for blocking the diffusion of sodium ions from the glass of the cell plate to the polyphenylene of the orientation layer

Claim 1

Black-white liquid crystal display (10) with a liquid crystal cell arranged between two crossed polarizers (13.o, 13.u) with an upper and lower cell plate (11.o, 11.u) and an upper and lower orientation layer (17) for providing an orientation direction (M.o, M.u) for adjacent liquid crystal molecules (18) of a layer (12) of a nematic liquid crystal between the cell plates, the molecules are twisted in relation to each other by the addition of a chiral compound, whereby the molecules adjoining the cell plates are oriented approximately parallel to the orientation direction of the adjacent orientation layer in each case, thereby producing a twist, characterized by the fact that the product of the distance between the plates and the anisotropy of the refractive index is not greater than about 0.6 μm the twist is at least 240°, the orientation layer (17) is formed of polyphenylene which causes a pretilt of at least 7° in the liquid crystal molecules (18) and orients the molecules, and between the orientation layer and the associated cell plate (11.o, 11.u) there is an insulation layer (16) for blocking the diffusion of sodium ions from the glass of the cell plate to the polyphenylene.