FPC & PCB MEMBRANE SWITCH
FPC (Flexible Printed Circuit board) or PCB (Rigid Printed Circuit Board) instead of silver flexible circuitry as bottom circuitry, we name that FPC membrane switch or PCB membrane switch.
1. FPC membrane switch:
FPC includes 1 mil up and bottom PI, 1 oz pressed copper foil and 1.5 mil immersion gold. Usual thickness is 0.135 mm.
FPC is better than silver circuitry. FPC can resist high temperature of 280 degrees and it’s resistance is low, only 20% of silver circuitry’s resistance; furthermore, LED on silver circuitry is more reliable than gluing LED on silver circuitry. Therefore, If there are many LEDs, environment’s temperature is high, or tail is very long, we can use FPC as below circuitry.
2. PCB membrane switch:
FR4 is from famous “Kingboard”, 1 oz pressed copper foil and 1.5 mil immersion gold. Usual thickness is 1.0 mm.