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Liquid Crystals and LCDs: How Cell Phones Resemble Carrots
A smartphone's tiny screen relies on the strange properties of liquid crystals. Check out Groupon's study of LCDs to learn how they create the vivid pictures in your pocket.
The term liquid crystal seems a contradiction, but a liquid crystal is actually neither a liquid nor a solid—it's both, stuck in a sort of chemical limbo with its molecules somewhere between the liquid and solid phases. When an electrical current passes through a liquid crystal, its molecular orientation changes, and so does the direction of light that passes through it. By sandwiching these crystals between polarized glass and manipulating the current passing through them, your phone is able to control the light they channel, resulting in the high-contrast images that appear on screen. Although our brains only see each pixel as a single dot, each consists of red, blue, and green subpixels that, when lit at various intensities, can emit more than 16 million colors.
Despite their advanced applications, liquid crystals are not a recent discovery. They were first identified in the late 19th century by a scientist studying cholesterol extracted from carrots—a natural source of liquid crystals, as are human beings and most other living things, which tend to have them in their cell membranes. Liquid crystals and LCDs were the subject of research and patent applications throughout the early 20th century—including one filed by Marconi’s Wireless Telegraph Company in 1936—and finally hit consumer electronics in the early 1970s, when they were introduced in wristwatches.