| 摘要 |
PROBLEM TO BE SOLVED: To realize miniaturization, by installing a metal film having a locally narrowed part on an easily splitting board, and by making centralized heat generation occur on the locally narrowed part of the metal film by overcurrent carrying, and by braking the easily splitting board by thermal stress generated by the centralized heat generation. SOLUTION: A metal film 1 having a locally narrowed part 11 of this current fuse element is installed on an easily splitting board 2. A breaking mechanism of an overcurrent by using the current fuse element is composed of such serial steps that, first of all, Joule heat is generated on the locally narrowed part 11 of the metal film 1 by an overcurrent, and then the locally narrowed part 11 of the metal film 1 and a nearby easily splitting board part 20 are heated by the Joule heat, and furthermore the easily splitting board 2 is broken by thermal stress by the heating. In this case, by the centralized heating of the locally narrowed part 11 of the metal film 1, the locally narrowed part 11 itself is changed into an insulator by oxidation, and the overcurrent breaking is preferably executed both by breaking by the thermal stress of the locally narrowed part 11 of the metal film 1 and by the change thereof into the insulator.
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