Nematic Materials for Active Matrix Addressing

The requirement of a very high and constant resistivity over time of nematic mixtures for TN-LCDs with active matrix addressing meant that new liquid crystals which met this and the other specifications, such as low viscosity and high positive dielectric anisotropy, were needed. The nitriles used in nematic mixtures for TN-LCDs with direct or multiplex addressing were soon found to be unsuitable for TN-LCDs with active matrix addressing. The polar nature of the cyano group leads to the solvation of ions from some of the layers on the 

Parentheses represent a monotropic transition temperature brackets represent an extrapolated virtual transition temperature Sma-N transition at 134 C. 

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Figure 5.5 Twisted nematic materials for active matrix addressing.

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