Twisted-untwisted bistable nematic LCDs

The parameters controlling the bistability are the angle (j) between the aUgning directions of the alignment layers and intrinsic pitch P of the liquid crystal. So far bistability has been observed for -nil p nil. The intrinsic pitch of the liquid crystal should be chosen heuris-tically in such a way that the (j) + n) twist state has the minimum free energy, that is ( + ji) is the intrinsic twist. Hence InQilP) = + n[16.  

When the liquid crystal is in the state with a twist angle of 360°, namely, = 2n, the transmittance is 

The angles of the polarizers as well as the twist angle (p can also be varied to achieve good performance. For example, consider a (-90°, 270°) bistable TN where (p = - 90°. The angles of 

When the hquid crystal is in the 270° twist state, d = 3 r/2. The transmittance is 

When r = 2V2 r, T(-90°) = 0 and T(270°) = 0.965 [26]. With the help of the simplified Mueller matrix method and the Poincare sphere, a general condition for optimized performance can be derived. The optimization considered here is only for one wavelength. In reality, the 

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There are several types of bistable nematic LCDs that have good performance characteristics. They are twisted-untwisted bistable nematic LCD [9-13], zenithal bistable nematic LCD [14,15], surface-induced bistable nematic LCD [16-19], mechanically bistable nematic LCD and bistable STN-LCD [20-24], A bistable nematic material has two bistable states with... 

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