Patent ID: 8094864

Claim:
A diaphragm unit for arranged to be used in a loudspeaker including a frame, said diaphragm comprising: a diaphragm extending in a longitudinal direction and having a first center line extends along the longitudinal direction; and an edge having an outer periphery and an inner periphery, the outer periphery being arranged to join to the frame, the inner periphery being joined to an outer periphery of the diaphragm, the edge having a convex surface having substantially a semi-circular cross section, wherein the convex surface of the edge have a plurality of grooves provided therein, the plurality of grooves extending from the inner periphery of the edge to the outer periphery of the edge, the plurality of grooves have cross sections each of which has a U-shape or a V-shape and has a center line extending along a bottom of each of the plurality of grooves, the plurality of grooves being arranged symmetrically about the first center line of the diaphragm, and a length of the center line of each of the grooves is greater than a circumferential length along the convex surface of the edge in a direction perpendicular to the inner periphery of the edge.