| abstract |
A compound having ferroelectric liquid crystal properties of the formula:n wherein A is the residue of a liquid crystal material or a liquid crystal compatible material;n X is 0 or S; n is 0 or 1; Y is any inert group which does not cause the melting point of the compound of Formula I to exceed 200°C; R 1 is selected from H, C 1-4 -alkyl and halogen; and R 2 is C 1-4 -alkyl or halogen; nprovided that R 1 and R 2 are different. In a suitable environment the compound is capable of alignment in two metastable states and is therefore suitable for use in multiplex-addressed, liquid crystal devices, such as flat bed large area screens and displays. |