In order to make a space required for installing a loudspeaker system smaller, there has been a strong voice in the market requesting a flat loudspeaker. A number of new creations have so far been announced for meeting the request.
A conventional flat loudspeaker is described below referring to FIG. 9, which shows a cross sectional side view.
As shown in FIG. 9, a damper 9, which is provided at a place inner from a magnetic gap 5, is not coupled direct with a voice coil 8, but the outer circumferential edge is connected to a plate 4 while the central portion is connected to a protrusion of a diaphragm 15 coming downward from the central part of the diaphragm. Thus, a cavity made available within the inner circumference of a magnet 2 is utilized as a space 6 for damper amplification. A loudspeaker can be fabricated in a thinner configuration adopting the above-described structure.
A magnetic circuit 1 is consisted of a magnet 2, a yoke 3 and a plate 4. Between the yoke 3 and the plate 4 is a magnetic gap 5. A frame 7 is fixed to the yoke 3. Voice coil 8 is connected to the diaphragm 15 at one end, while the other end is adapted to the magnetic gap 5. An edge 10 is connected at the inner circumference with the outer circumferential portion of the diaphragm 15, and the outer circumference of edge is connected with the inner rim section of the frame 7.
In assembling the above described conventional loudspeaker, the voice coil 8 has to be inserted to a right position in the magnetic gap 5 in a state where the voice coil 8 was already integrated with the diaphragm 15. Therefore, there is a substantially high possibility that the voice coil 8 is disposed oblique and/or eccentric to the magnetic gap 5. This leads to a possibility for the coil of the voice coil 8 coming in touch with the plate 4 or the yoke 3, which generates abnormal sounds.
The present invention addresses the above problem, and aims to present a loudspeaker improving the trade-off between the flat contour and the low rejection rate.