Microelectromechanical systems (MEMS) combine highly miniaturized electrical and mechanical components (parts) on a special type of computer chip. MEMS range from such simple machines as levers to complicated safety locks that prevent nuclear weapons from exploding accidentally. Some MEMS devices are no larger than a grain of sand. They are usually measured in micrometers. A micrometer is 0.001 millimeter or 1/25,400 of an inch.
The process used to create MEMS is similar to that used to make computer chips. Scientists and engineers create MEMS on a specially treated wafer, usually made of the element silicon, but sometimes made of layers of glass or plastic. In a common method of MEMS production, a process called etching is used to shape microscopic gears, beams, and other structures by dissolving parts of the wafer.
MEMS technology produces microscopic machines that can act as sensors, perform mechanical functions, and create visual effects. In an automobile, MEMS detect collisions and direct air bags to inflate, measure engine oil pressure and tire air pressure, and track the speed of rotation of each wheel to assist an antilock-braking system. In inkjet printers, MEMS pump ink and deposit it onto paper. In another MEMS application, rapidly moving microminiature mirrors project multicolored images onto a computer screen.
Researchers began working to develop MEMS in the late 1960’s. MEMS first appeared in consumer products in the 1980’s as sensors in automobiles.
