Patent ID: 8542861
Filing Date: 2013-09-24
Classification: H04R

Abstract:
1. A loudspeaker comprising: a diaphragm; a magnetic circuit that is provided on a rear side of the diaphragm, the magnetic circuit comprising a yoke shaped as a container opening towards the diaphragm and including a bottom wall having an inner surface that faces the diaphragm, a plate that cooperates with the yoke to form a magnetic gap therebetween, and a magnet having a first surface fixed to the plate and a second surface, opposite to the first surface, fixed to the inner surface of the bottom wall of the yoke; a voice coil that is directly or indirectly joined to the diaphragm along an outer shape of the diaphragm and extends into the magnetic gap to create a first passage within the magnetic gap that communicates between a space between the rear side of the diaphragm and an upper surface of the plate and a space outside of the loudspeaker; a magnetic fluid that is disposed within the magnetic gap; and a plurality of first edge pieces that are provided at different positions at an outer portion of the diaphragm for vibratably supporting the diaphragm, each of the first edge pieces having a curved cross-sectional shape when viewed in a longitudinal cross-section taken along a central axis of the loudspeaker, wherein an entirety of the outer edge of the diaphragm is not supported and the plurality of first edge pieces only support a portion of the diaphragm at the outer portion, wherein the magnetic fluid wherein the bottom wall of the yoke, the magnet and the plate have a first hole that passes therethrough and forms a second passage that communicates between the space between the rear side of the diaphragm and the upper surface of the plate and the space outside of the loudspeaker.