A particular form of video technology in portable devices, clocks, watches, and computing devices. An acronym for Liquid Crystal Display. LCD displays utilize two sheets of polarizing material with a liquid crystal solution between them. An electric current passed through the liquid causes the crystals to align so that light cannot pass through them. Each crystal, therefore, is like a shutter, either allowing light to pass through or blocking the light. In clocks and counters that use LCDs, the pattern often emulates LEDs, though LCDs are NOT diodes. Monochrome LCD images usually appear as blue or dark gray images on top of a grayish-white background. Color LCD displays use two basic techniques for producing color, passive matrix is the less expensive of the two technologies. The other technology, called thin film transistor (TFT) or active matrix, produces color images that are as sharp as traditional CRT displays, but the technology is expensive. Recent passive matrix displays using new CSTN and DSTN technologies produce sharp colors rivaling active matrix displays. Most LCD screens used in notebook computers are backlit to make them easier to read.