Layers of a Membrane Switch
For over 67 years Bovie Printing And Fabrication has been a leading manufacturer of Membrane Switches, a product widely used in appliance, medical, and the electronics industry. Membrane Switches offer an economical alternative to mechanical switches because they allow for graphic overlay design, and can facilitate brand marking. A typical Membrane Switch is constructed in the following layers:
- The graphic overlay layer is a polyester or polycarbonate film, printed on the second surface with a switch location, and copy required. The display of the buttons can be flat or embossed, with led windows, which add functionality.
- Top circuit layer contains shorting pads which close the electrical circuit when depressed through a spacer layer.
- Spacer layers act as a circular spring separating the two circuits. The function of the spacer is to allow room inside the switch for the tactile domes to rest without being subjected to partial compression by the layers around the domes.
- The bottom circuit layer has both poles, and the switch array, and the tail which connects to the printed circuit board.
- Adhesive layers allow the switch to be permanently mounted onto a smooth surface.