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Liquid Crystal Display - LCD

LCD Inventors James Fergason, George Heilmeier

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Simple LCD Screen

Simple LCD Screen

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An LCD or liquid crystal display is a type of flat panel display commonly used in digital devices, for example: digital clocks, appliance displays, and portable computers.

How an LCD Works

According to a PC world article, liquid crystals are liquid chemicals whose molecules can be aligned precisely when subjected to electrical fields, much in the way metal shavings line up in the field of a magnet. When properly aligned, the liquid crystals allow light to pass through.

A simple monochrome LCD display has two sheets of polarizing material with a liquid crystal solution sandwiched between them. Electricity is applied to the solution and causes the crystals to align in patterns. Each crystal, therefore is either opaque or transparent, forming the numbers or text that we can read.

History of Liquid Crystal Displays - LCD

In 1888, liquid crystals were first discovered in cholesterol extracted from carrots by Austrian botanist and chemist, Friedrich Reinitzer.

In 1962, RCA researcher Richard Williams generated stripe-patterns in a thin layer of liquid crystal material by the application of a voltage. This effect is based on an electro-hydrodynamic instability forming what is now called “Williams domains” inside the liquid crystal.

According to the IEEE, "Between 1964 and 1968, at the RCA David Sarnoff Research Center in Princeton, New Jersey, a team of engineers and scientists led by George Heilmeier with Louis Zanoni and Lucian Barton, devised a method for electronic control of light reflected from liquid crystals and demonstrated the first liquid crystal display. Their work launched a global industry that now produces millions of LCDs."

Heilmeier's liquid crystal displays used what he called DSM or dynamic scattering method, wherein an electrical charge is applied which rearranges the molecules so that they scatter light.

The DSM design worked poorly and proved to be too power hungry and was replaced by an improved version, which used the twisted nematic field effect of liquid crystals invented by James Fergason in 1969.

James Fergason

Inventor, James Fergason holds some of the fundamental patents in liquid crystal displays filed in the early 1970's, including key US patent number 3,731,986 for "Display Devices Utilizing Liquid Crystal Light Modulation"

In 1972, the International Liquid Crystal Company (ILIXCO) owned by James Fergason produced the first modern LCD watch based on James Fergason's patent.

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