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Fergason noticed other interesting properties of the materials as his experiments progressed. "When I started looking at liquid crystals, their optical activity caught my eye. They were intriguing as I got more and more into them. I found all kinds of things people hadn't thought about. They were the opposite of a mirror in terms of polarized light. It was great fun."
He was issued his first patent in December 1963 for his use of cholesteric liquid crystals in temperature sensing applications. This technique is still used today in products ranging from forehead thermometers to mood rings.
A Twist on Liquid Crystals
A few years later, in 1966, Fergason was recruited to join the Liquid Crystal Institute at Kent State University. There he discovered the twisted nematic field effect of liquid crystals - the key discovery that led to the creation of today's liquid crystal displays (LCDs).
Fergason observed that liquid crystals are naturally twisted, but could be untwisted with an electric current. Without a charge, light can pass through the liquid crystal cell. When varying amounts of voltage are applied, the liquid crystals can twist up to 90 degrees like a Venetian blind to block the light's path.
Earlier attempts to develop LCDs required lots of power that degraded the liquid crystal materials quickly. "Nobody thought you could switch polarized light efficiently enough to make a display out of it," he said. He proved that shuttering a liquid crystal requires very little energy, making nematic LCDs a highly efficient way to control light.