| 摘要 |
PROBLEM TO BE SOLVED: To provide an acoustic transducer for improving a conventional balanced version pendulum type fault. SOLUTION: The acoustic transducer includes, within a casing (300), a diaphragm (350) at least a portion of which is constituted of magnetically permeable material (358). The diaphragm is supported by upper and lower holding rings between pole pieces (380 and 320). A magnet (340) is arranged between the pole pieces. The diaphragm has a portion (356) of magnetically permeable material magnetically coupled to an electromagnetic coil (360). Acoustic cavities (326) are defined between the pole pieces and the diaphragm. Passages in the casing and in at least one of the pole pieces allow movement of air in and out of at least one of the cavities. COPYRIGHT: (C)2008,JPO&INPIT
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