membrane keyboard - Computer Definition
(1) Most QWERTY computer keyboards use a single rubber-like membrane underneath the keys that makes contact with a circuit board when the key is fully depressed. Also called a "dome switch keyboard," this style is also found on many types of keypads. There is less tactile sensation from membrane keyboards than there is when individual key switches are used (see mechanical keyboard).
(2) A keyboard that tolerates dirt and spillage that would otherwise cause a regular keyboard to fail. Membrane keyboards use a flexible plastic sheet printed with the key pattern on top and electrically conductive ink on the underside. When a key is pressed, it pushes the top layer down through a spacer layer of holes and makes contact with the circuit at the bottom. Widely used in self-service applications, there may be little movement in the keys, and a beep or LED is often used for feedback.