Liquid crystal mixture

The liquid crystal in a TV isn't one substance. It's a blend of typically 10 to 20 compounds, mixed so the result behaves well through everything a TV meets, from a cold delivery truck to a warm living room.

Each ingredient is a liquid crystal molecule, a stiff rod a couple of nanometers long. No single compound has every property a display needs. One may stay liquid-crystalline over a wide temperature range, another may turn quickly, another may respond strongly to voltage or bend light by just the right amount. Chemists blend them in measured proportions, partly because a mixture can melt at a lower temperature than any of its parts. The blend is then purified to remove ions and moisture, which would let charge leak away and cause flicker or ghost images.

In the LCD panel, the mixture fills a gap a few micrometers wide, so a whole 65-inch panel needs only about a teaspoon. The molecules line up with the alignment layers on the glass and turn when voltage is applied, changing how light passes through. Liquid crystals were first described in 1888 by the Austrian botanist Friedrich Reinitzer, who noticed a compound from carrots seemed to melt twice.