Liquid Crystal Displays: Fundamental Physics and Technology

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The Transistor and Integrated Circuit

Liquid crystal displays work because the liquid crystal can polarize light; the polarization changes the intensity of a source of light that passes through each individual picture element making up the whole image. The polarization depends on the voltage that turns the liquid crystal molecules, and that voltage depends on semiconductors and integrated circuits to control and deliver the appropriate voltage. The liquid crystal display and almost all the other now all-too-familiar electronic devices of the modern age owe their existence to the transistors and integrated circuits within. Giving life to those devices is the semiconductor, the very soul of the transistor and integrated circuit, but just exactly what is a semiconductor, and how do transistors and integrated circuits control the voltage to the picture elements?

The Bohr Atom

The transistor is the source of our modern electronics era, and the spirit of the transistor is found in its semiconductor soul. But just what is a “semiconductor”? Is it an electrical conductor, is it an insulator, or both; or is it half of each? But how can one be two, and just what does “half a conductor” mean? The seemingly mystical yin and yang of conductive-resistive duality in fact will be seen to owe its essence to foreign matter.

Any material thing can be described and distinguished by its resistivity (resistance to electrical conduction); for example, the aluminum wiring used in transistors has a ...