What’s the difference between LCD and plasma?
A?plasma?screen?looks?similar to an LCD, but works in a completely different way: each pixel is effectively a microscopic?fluorescent lamp?glowing with plasma. A plasma is a very hot form of gas in which the?atoms?have blown apart to make negatively charged electrons and positively charged ions (atoms minus their electrons). These move about freely, producing a fuzzy glow of light whenever they collide. Plasma screens can be made much bigger than ordinary cathode-ray tube televisions, but they are also much more expensive.
A brief history of LCDs
- 1888: Friedrich Reinitzer, an Austrian plant scientist, discovers liquid crystals while studying a chemical called cholesteryl benzoate. It seems to have two distinct crystal forms, one solid and one liquid, each with its own melting point.
- 1889: Building on Reinitzer’s work, German chemist and physicist Otto Lehmann coins the term “liquid crystals” (originally, “flowing crystals” or “fliessende Krystalle” in German) and carries out more detailed research using polarized light. Although his work is nominated for a Nobel Prize, he never actually wins one.
- 1962: RCA’s?Richard Williams?begins to research the optical properties of nematic liquid crystals. He files his groundbreaking LCD patent (US Patent 3,322,485) on November 9, 1962 and it’s finally granted almost five years later on May 30, 1967.
- 1960s: RCA engineers like?George Heilmeier?build on this theoretical research to produce the very first practical electronic displays, hoping to create LCD televisions.
- 1968: RCA publicly unveils LCD technology at a press conference, prompting?The New York Times?to anticipate products like “A thin television screen that can be hung on the living-room wall like a painting.”
- 1968: French scientist?Pierre-Gilles de Gennes?carries out groundbreaking research into phase transitions involving liquid crystals, for which he wins the?Nobel Prize in Physics?in 1991.
- 1969: RCA’s Wolfgang Helfrich develops twisted nematic LCDs based on polarized light, but the company is skeptical and shies away from developing them. At Kent State University, James Fergason develops and patents an alternative version of the same idea. Today, Helfrich, his collaborator Martin Schadt, and Fergason are jointly credited with inventing the modern LCD.
- 1970: Having?failed to commercialize the LCD, RCA sells its technology to Timex, which popularizes LCDs in the first digital wristwatches.
- 1973:?Sharp?unveils the world’s first LCD pocket calculator (the EL-805).
- 1980: STN (super twisted nematic) displays appear, with far more pixels offering higher resolution images.
- 1988: 100 years after the discovery of liquid crystals, Sharp sounds the death knell for cathode-ray tubes when it produces the first 14-inch color TV with a TFT (thin-film transistor) LCD display.