Why is LCD (Liquid Crystal Display) device so named?
The LCD device is built around a material, which is a liquid as far as its flow properties are concerned. However, the large, rod like organic molecules constituting the material can be aligned in an orderly manner, more like a crystal. Hence the name Liquid Crystal Display (LCD). Such alignment is achieved in the devices by application of a localized electric field between an opaque and another transparent electrode. The aligned molecules form a pattern in the shape and size of the transparent electrode and the pattern is observed in polarised light. The device consists of a pair of polariser films on either side of the assembly of the two electrodes sandwiching the liquid crystal layer, oriented at perpendicular directions. Further the special design of the electrodes twists the crystal to different extents, which controls the opacity or visibility of the desired pattern. Different innovative combinations of liquid crystal materials, pattern and strengths of the electric field and orientations of the polarising filters produce many special visual effects of the liquid crystal displays.