Rubber Keypads
Rubber keypads are alternatives to membrane switch graphics for user interface on electronics with membrane switches. They are made of a silicone elastomeric rubber and provide tactile feedback which tells the typer their keystroke has been registered, as well as graphics and color on the key. They exhibit a wide temperature resistance and color range, and generally last throughout the life of their product. Rubber keypads are either used strictly as a tactile element, or as a conductive element which has a conductor on the bottom of each key. They are used mostly in the electronics industry for remote controls, computer keyboards, phones (cellular and land line), calculators, adding machines, PDAs and certain applications in the automotive industry.
Silicone rubber keypads are compression molded and custom configured parts manufactured by thermosetting. During the molding process, silicone rubber is inserted into a molding machine. Heat and pressure are applied to the material in a mold, which forms it into the desired keypad shape. After the silicone rubber has cured, post process finishing is applied, like laser etching, silicone ink graphic printing and matte or glossy textures are added to the surface. Conductive keypads are made slightly differently than non-conductive. The silicone rubber is impregnated with carbon which is thermally bonded to the keypad during compression molding and placed over a circuit board or switch circuit.