| 摘要 |
PURPOSE:To obtain inexpensively a thin, small-sized speaker with light weight by opposing closely the magnetic poles of same polarity of a couple of cylindrical magnets magnetized axially, providing a voice coil interlinked with orthogonal magnetic flux axially generated from the opposed parts of the magnets and a flat diaphragm fitting said voice coil at the inner circumference. CONSTITUTION:A couple of magnets 1, 2 are made of rare-earth metal, the magnetic poles of same polarity are opposed via a spacer 3 made of a magnetic material such as soft iron core or the like and bonded by an adhesives. Further, the couple of the magnets 1, 2 are fixed to the center position of a frame 4 made of a circular nonmagnetic material having nearly the channel shape of cross section. The magnetic flux generated from the N pole of the magnets 1, 2 is concentrated all on the end and diverged. Thus, a strong magnetic field is formed at the surrounding of the opposed parts of the magnets 1, 2. When an electric signal is fed to the voice coil 7, the flat diaphragm 5 receives force in parallel with the axial direction of the magnets 1, 2, the diaphragm 5 is vibrated in response to the force and sound is irradiated. A large sized magnet and an accompanying pole, a plate and a yoke are not required, the constitution is made simple for the extent above and the speaker with small sized, light weight is obtained inexpensively. |
