| 摘要 |
PROBLEM TO BE SOLVED: To provide an electroacoustic transducer which allows piezoelectric acoustic components to be miniaturized furthermore and is capable of effectively generating sounds having frequencies lower than a resonance frequency of a front air chamber without attenuation. SOLUTION: In the electroacoustic transducer wherein a piezoelectric acoustic component including a piezoelectric diaphragm 30 is surface-mounted on a circuit board 10, a sound output hole of the piezoelectric acoustic component 20 is formed in a face of a case, which doesn't face the circuit board 10, and an open hole 29 is formed in a face of the case, which faces the circuit board, and a through hole 13 is formed in a part of the circuit board corresponding to the open hole 29. A higher sound pressure can be obtained in comparison with sounding at the resonance frequency of the front air chamber when the piezoelectric diaphragm is operated at a frequency or its neighboring frequencies, lower than the resonance frequency of the front air chamber, and sounds emitted from the sound output hole 28 can be prevented from being attenuated by sounds emitted from the open hole 29. COPYRIGHT: (C)2008,JPO&INPIT
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