A matrix addressable bistable nematic liquid-crystal display with electric field writing and thermal erasure

We describe the fabrication and performance of a 20 × 40 element bistable liquid-crystal display using a dye guest in a nematic host. The bistable configuration ensures the long term memory of the written display. The electrical writing procedure together with the use of segmented subpels produces sharp, uniform switching thresholds resulting in clearly written displays with good contrast. Both 2:1 and 3:1 matrix addressing schemes are possible. The thermal erasure scheme is discussed in detail and the influence of the boundary aligning material and the resulting nematic director tilt angle is investigated both theoretically and experimentally. Results are presented for both reflection and transmission displays.