ELECTROSTATIC BREAKDOWN PREVENTING STRUCTURE

PROBLEM TO BE SOLVED: To provide a structure for preventing a malfunction caused by the static electricity at a switch operation part or an electrostatic breakdown, for the structure having an electrically conductive operation part like a plating, or a metallic film or an ornament. SOLUTION: One or a plurality of protrusions of pins or ribs electrically connected with an operation surface are formed on a part for operation having conductivity like a plating, or a metallic film or an ornament, and a through-hole is formed on a printed wiring board forming a circuit. The inner surface of the through-hole is made conductive by a foil or the like and the conductive part is connected to a safe circuit not generating malfunction or breakdown. One or a plurality of protrusions of pins or ribs formed on the operation part is fitted into the through-hole with such a minimum gap that the switch can move without being blocked when operated, so that the distance becomes shorter than the distance between the other conductive part of an operation knob and the circuit. COPYRIGHT: (C)2004,JPO