Membrane switch device and keyboard device

A membrane switch device, comprising:

• a first membrane layer comprising a first surface, a first side edge, and a plurality of first conductive wires, wherein the first surface has a first outlet area, the first outlet area has a first no-wire area and a first wire area, the first conductive wires are on the first surface and extending to the first wire area to form a plurality of first contact pads;
• a second membrane layer comprising a second surface, a second side edge, and a plurality of second conductive wires, wherein the second surface has a second outlet area, the second outlet area has a second no-wire area and a second wire area, the second conductive wires are on the second surface and extending to the second wire area to form a plurality of second contact pads;
• a spacing layer between the first membrane layer and the second membrane layer;
• and
• a flexible printed circuit board comprising a wire-connecting end, a plurality of first electrical lines, a plurality of second electrical lines, a first protection layer, a second protection layer, a first connection surface, and a second connection surface opposite to the first connection surface, wherein the first electrical lines are on the first connection surface and extending to the wire-connecting end to form a plurality of first connecting terminals, the first protection layer covers the first electrical lines to expose the first connecting terminals, the second electrical lines are on the second connection surface and extending to the wire-connecting end to form a plurality of second connecting terminals, the second protection layer covers the second electrical lines to expose the second connecting terminals;
• wherein the wire-connecting end of the flexible printed circuit board is between the first outlet area of the first membrane layer and the second outlet area of the second membrane layer, the first connecting terminals are electrically connected to the first contact pads, correspondingly, the second connecting terminals are electrically connected to the second contact pads, correspondingly;
• wherein the first protection layer and the first contact pads are not overlapped with each other, and the second protection layer and the second contact pads are not overlapped with each other.