A membrane switch is light touch keyboard by using a series of layers of polymer films and adhensives. It consist of 6 layers, called graphic overlay, overlay adhesive, upper circuit layer, circuit spacer, lower circuit layer and back adhesive. Membrane switch has a good waterproof, dustproof,prevent the erosion of harmful gas.Membrane Switches are widely used in various electronics fields such as Industrial controls, measurement instruments, fitness equipment, medical devices, chemistry and metallurgy, testing equipment, electronic scale, environmental protection equipment, appliances, building safety system and fire alarm system.