| 摘要 |
PROBLEM TO BE SOLVED: To provide a loudspeaker for use in a portable phone or the like capable of raising reproduction sound pressure by solving the problem that the reproduction sound pressure is suppressed because a flow passage of air on the rear surface of a diaphragm is prolonged to result in an increase in air resistance. SOLUTION: The loudspeaker comprises a frame 6 including a magnetic circuit 1 coupled thereto and having a magnetic gap 5, and a diaphragm 8 having a periphery coupled to the frame 6 and having a voice coil 7 that is coupled with the center of the diaphragm and is fitted in the magnetic gap 5. It further comprises a communication means for communicating a gap formed between the rear surface of the diaphragm 8 and the interior of the voice coil 7 with the outside. By this constitution, it is possible to reduce the flow resistance of air applied to the diaphragm 8 by shortening a flow passage of air on the rear surface of the diaphragm 8, so that it is possible to raise the reproduction sound pressure. COPYRIGHT: (C)2006,JPO&NCIPI
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