Visual display technology which uses liquid crystals that change their alignment and become visible when electrical voltage is applied to them. Liquid crystals do not emit light directly. They reflect light from an external source, or can be illuminated from behind. LCDs may be made up of any number of segments, large as in the elements of a digital clock, or tiny, representing pixels on a computer or video monitor. They may be in color or monochrome, depending on the application.