127. L. C. D.

The display on calculators, Television screens and computer monitors are fast becoming Liquid crystal Display, popularly known as LCD.

A unique group of natural substances give rise to LCD. These substances are neither quite solids nor quite liquids, at normal room temperatures. They are called Liquid Crystals.

Liquid crystals are complex organic chemicals which can flow like a liquid and can also form regular patterns like the solid crystals.

Liquid crystals were first observed and studied in detail by Friedrich Reinitzer in 1888. The full potential of the liquid crystals has been exploited only in the past few decades.

In LCD, the crystals are sandwiched between two transparent electrodes, which transmit electric current. Depending on the current sent through the electrodes, images are displayed.

For displaying numbers as in a watch or a clock, seven equal segments are used, to form the shape of two small squares, placed one on top of the other. By controlling the current sent to one or more of these segments, all the other numbers ranging from zero to nine are formed.

LCD screens are flat, thin and light in weight. This has made it possible, for the size of the home television, to grow from big to bigger, all the time.

In a few years’ time we may have an LCD screen big enough to cover the entire surface of a wall in our drawing room, giving us the pride and pleasure of having a theater our very own!.

Visalakshi Ramani