Liquid crystal display (LCD) is a popular flat-panel display technology found in many TVs, computer monitors, smartphones, and tablets. The development of the LCD started with Friedrich Reinitzer experimenting with carrots in the 1880s and discovering that some chemicals can exhibit a “liquid crystal” state.
RCA produced the first LCD in 1967, but it didn’t become really usable until scientists in Switzerland figured out how to manipulate the twisted nematic (TN) structure of liquid crystal with electricity.
Today, LCDs rely on one of three different types of backlights: reflective, transmissive, and transflective. Most LCDs are transmissive, but reflective screens are still popular in things like calculators. Transflective screens have a backlight but can also be viewed in ambient light. They are, however, expensive and can lose some contrast.
SparkFun’s LCDs: https://www.sparkfun.com/categories/76