The twisted-and supertwisted-nematic liquid crystals

The twisted nematic (TN) and supertwisted nematic (STN) liquid crystals are widely used in liquid crystal displays. The former is used in wrist watches and calculators while the latter is used in notebook computers. 

Vc is typically of order of one volt. Now, polarizers are mounted on the top and bottom glass plates such that their polarization directions are along or normal to the neighboring liquid crystal molecules on both plates. When 

STN has a twist angle greater than 180 degrees and its electric-optical response is much steeper so that they can be driven in the multiplexing displays such as those found in the SVGA format color notebook computers. 

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