liquid crystal, liquid whose component particles, atoms or molecules, tend to arrange themselves with a degree of order far exceeding that found in ordinary liquids and approaching that of solid crystals. As a result, liquid crystals have many of the optical properties of solid crystals. Moreover, since the order is not as firmly fixed as that of a solid crystal, it can be easily modified with corresponding changes in the optical properties; typically, a small electrical impulse darkens the crystal so that it is clearly visible against the lighter background of neutral crystals. An array of seven lozenges, each of which can be darkened by a separate impulse, can yield any digit. Thus, liquid crystal displays (LCDs) have become the most common means of producing visual readouts on such devices as digital clocks and electronic calculators. Some liquid crystals vary the color of the light that they reflect as their temperature changes. Since the colors reflected at any given temperature are quite specific, temperature can be measured by this means to an accuracy of 0.1°C;.

Optoelectronic device used in displays for watches, calculators, notebook computers, and other electronic devices. Current passed through specific portions of the liquid crystal solution causes the crystals to align, blocking the passage of light. Doing so in a controlled and organized manner produces visual images on the display screen. The advantage of LCDs is that they are much lighter and consume less power than other display technologies (e.g., cathode-ray tubes). These characteristics make them an ideal choice for flat-panel displays, as in portable laptop and notebook computers.

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Substance that flows like a liquid but maintains some of the ordered structure characteristic of a crystal. Some organic substances do not melt directly when heated but instead turn from a crystalline solid to a liquid crystalline state. When heated further, a true liquid is formed. Liquid crystals have unique properties. The structures are easily affected by changes in mechanical stress, electromagnetic fields, temperature, and chemical environment. Seealso liquid crystal display.

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