| 摘要 |
An electricity-to-sound transducer has a diaphragm having an asymmetric shape which is flat when viewed from a direction of vibration, with major and minor axes, having continuous curvatures of concavity and convexity in a direction of sound irradiation, provided with a slot formed almost at a center of the diaphragm in a direction perpendicular to a longitudinal direction of the diaphragm. An edge portion is formed as surrounding an outer periphery of the diaphragm, an inner section of the edge portion being connected to the outer periphery, the edge portion sustaining the diaphragm so that it can vibrate. A voice coil bobbin has a winding portion around which a voice coil is wound split into two portions in the longitudinal direction of the diaphragm, the bobbin being attached to a rear surface of the diaphragm while the two portions are joined to each other, the joined portions forming a reinforcing beam that reaches a rear surface of a bottom of the slot of the diaphragm. The voice coil is applied flux by a magnetic circuit for vibration. The outer periphery of the edge portion and the magnetic circuit are sustained by a frame. Another type of transducer also has a diaphragm and a voice coil bobbin. A slot of the diaphragm has walls on a bottom of slot, on both ends of the slot in a direction of the major axis and on both ends of the slot in a direction of the minor axis, the slot protruding in a direction of a rear surface of the diaphragm to form a protrusion. The voice coil bobbin is attached to the rear surface of the diaphragm, an inner size of the bobbin almost at the center in the longitudinal direction being larger than an outer size of the protrusion in the direction of the minor axis, the protrusion being inserted into the bobbin, a gap between an inner wall of the bobbin and the protrusion being filled with an adhesive so that the protrusion and the bobbin are bonded to each other.
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