Memory light valve : smectic-A liquid crystal associated to a photoconductor

The memory light valve described consists of an amorphous selenium photoconductor and a planar oriented smectic-A liquid crystal sandwiched between two transparent electrodes. The operation of the device is governed by a novel photo-electro-optic effect. Namely the role of the photoconductor is not only to transfer the voltage to the liquid crystal (few µs) but also to store it for a sufficient time so as to generate the defects in the smectic-A (typically 10 ms). The performances of the light valve are the following: