| 摘要 |
PROBLEM TO BE SOLVED: To form a discharge gap with accurate dimension and construct small and at a low cost by applying a plating to the end face of a land exposed at the top and bottom surfaces of an insulative gap layer so that the resultant discharge gap is formed protrusively. SOLUTION: A copper foil is attached by hot press to each surface of an insulative film, and the area where no copper foil is required is removed by etching so that gap forming lands 202 and wiring parts 203 for a pair of electrostatic protection elements are formed. Therein a plurality of protection element wiring parts are arranged in series in the longitudinal direction in such an arrangement as pinching a terminal for end face connection and in the crosswise direction parallel lines are formed continuously. Holes 3 having a specified diameter are provided, and each hole is furnished with a protrusion owing to a thickened copper plating so that the shortest distance 5-150μm is produced at the end face of the gap forming land 202 exposed at the inner wall. This heightens the accuracy of the discharge gap, provide precise controllability for the discharge voltage, allows manufacturing simply at a low cost, and produces stable characteristics through electric discharging at the protruded part.
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