rubber keypad / membrane
Membrane switches incorporate silicone-rubber keypads to improve the aesthetic look and feel of a switch. Designs have a large variety of effects from embossed and debossed features, printed text, painted icons, backlighting and even rocker/toggle actuators. Polyurethane, epoxy and UV coatings available can protect keypads from the environment and abuse.
The keypad utilizes a variety of contact systems ranging from carbon pills, to gold pills, to actuating tactile metal domes in a membrane-switch assembly. Mounting methods used to apply the rubber actuator to the switch may vary. One simple method of mounting rubber actuator is double-sided pressure-sensitive silicone-rubber adhesive. This is applied to a carrier on one side, and the applicable mounting adhesive is applied to the other. Another mounting method includes a simple pull-through molded into the rubber itself. The pull-through is then pulled through a printed circuit board substrate, where an interference fit secures the rubber component to the assembly.