| 摘要 |
PROBLEM TO BE SOLVED: To prevent a piezoelectric diaphragm from coming off a support member and to prevent a short-circuit failure due to vibration of the piezoelectric diaphragm by coating a circumferential edge of the piezoelectric diaphragm whose center is fitted to an acoustic diaphragm via the support member by means of an insulating material. SOLUTION: This loudspeaker 10 is provided with a piezoelectric diaphragm 12 fitted to an acoustic diaphragm 14 via a plastic-made support member 16. The piezoelectric diaphragm 12 has a ceramic or piezoelectric element layer 12b made of a ceramic formed on both side faces of a circular metallic plate 12a, and a through-hole is formed in the center of the piezoelectric diaphragm 12, an insulation material 18 is placed to a circumferential part of the piezoelectric diaphragm 12, the insulation material 18 covers parts of the metallic plate 12a exposed along its circumferential part so as to insulate electrically the parts from other components. The insulation material is a plastic such as a vinyl chloride or an insulating rubber.
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