| 摘要 |
PURPOSE:To improve productivity and overall stiffness and to make easier to expand the regenerative band of the sound frequency characteristics, by adhering a surfacing material to both sides of a core material forming a film by means of heat press adhering or solvent based adhering, etc. CONSTITUTION:The peripheral of a rectangular flat board diaphragm 14 is supported by a frame 16 fitted with an edge part 15 to a yoke 12 which constitutes a magnetic circuit. A voice coil bobbin 17 is fitted to a position deviated in longitudinal direction from the central part of the diaphragm 14. A voice coil 19 is arranged between the bobbin 17 and a magnetic gap so that the voice coil can perform piston motion. The diaphragm 14 is made of thermoplastic resin so that projecting and recessing ribs 20', 20''... parallel in longitudinal direction by means of press molding, and a rib 21' to the opposite side to a voice coil driving part 14a alternately with the ribs 20', 20''... and coupled with the ribs 20', 20''... are provided. Both sides of a core material 22 of the rib 21' are adhered with a surfacing material 23 having high elasticity. As a result, the productivity and overall stiffness are improved, and the regenerative band of the sound pressure frequency characteristics is easily expanded. |
