Optimization of single layer and double layer general twisted nematic liquid crystal displays

The author derives the Jones matrix representation for a general DTN (double-layer twisted nematic) display with an arbitrary uniform pretilt angle. This representation is used to obtain an analytic closed-form expression for the optical transmission for a DTN display. The optimum design criteria for both single-layer and double-layer TN displays are then obtained. For the single TN display, two design criteria have to be met: one is the optimum cell thickness; the other is optimum polarizer orientation. Design criteria for special cases of single layer TN displays are presented in tabular form. For the DTN display, at the field-off state, the author obtains a completely dark state (for crossed polarizer arrangement) or a completely bright state (for parallel polarizer arrangement). The optimum cell-thickness design criterion obtained for the single-layer TN display is applicable to both layers of the DTN display, and the optimum polarizer orientation criterion for the single TN displays is also applicable for the DTN display.<
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