Liquid crystals, displays and devices for optical processing

The principal characteristics of displays are discussed with reference to various technologies. Commonalities and contrasts in the ways in which different devices achieve colour or can be addressed are emphasised. Factors limiting the resolution of devices are touched on. The main part of the paper gives a review of liquid-crystal technology. Basic aspects are covered under the headings of 'phases', 'textures' and 'anisotropy'. Applications to display are treated under 'effects' and 'addressing'; the latter topic including optical addressing which leads into direct 'imaging' into liquid-crystal devices using thermo-optic effects or separate light-sensitive sub-components. Devices capable of image-wise modulation by optical addressing are discussed under the heading 'spatial light modulators'.