Each
key operated is an individual
switch. When you press down on a key,
hard contact is made between the two
poles of a switch. The connection conducts
electricity which, detected through a
matrix array, indicates which key is pressed.
The design is based on molded rubber sheets which provide the spring action needed to return the keys to their rest positions as well as holding one of the contacts required for switching. This rubber is carefully tailored into domes which collapse under pressure in a controlled manner that gives a positive over-center action and feel to each key.