| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an inexpensive electromagnetic transducer that has high rigidity of a diaphragm and satisfactory performance. <P>SOLUTION: In a frame 15, a plurality of strip-shaped permanent magnets 13 having different polarities at obverse and reverse surfaces are fixed at predetermined intervals with the polarities alternated. Iron plates 16 are bonded to end surfaces of the permanent magnets 13 opposite to the surfaces fixed to the frame 15. A diaphragm 11 is mounted on the frame 15 so as to cover the permanent magnets 13 and the iron plates 16. The diaphragm 11 has an uneven shape corresponding to an uneven structure comprising the plurality of permanent magnets 13 fixed at the predetermined intervals, and diaphragm reference surfaces 11d defining concaving portions of the uneven shape are in the same height position as the iron plates 16, that is, in a high magnetic flux density position, and has a voice coil 11b formed thereon. Furthermore, a diaphragm surface material 17 is attached to a surface side of diaphragm protruding portions 11c to provide improved rigidity. <P>COPYRIGHT: (C)2012,JPO&INPIT |
