Patent ID: 6385328
Filing Date: 2002-05-07
Classification: H04R

Abstract:
An electro-acoustic micro-transducer comprising:a yoke formed of an internal groove and a vertical incision portion for removing a predetermined vertical wall at at least one side surface; a permanent magnet installed in the groove of the yoke, for generating a non-alternating magnetic field; a plate mounted on the upper surface of the permanent magnet, for forming a magnetic gap between the outer circumferential surface and the upper end of the yoke; a coil wound on a bobbin, which generates an alternating magnetic field when an electric drive signal is externally applied via first and second lead wires and is disposed in the magnetic gap to be displaced up and down according to an interaction with a non-alternating magnetic field generated from the permanent magnet; a cylindrical frame in which the outer circumferential portion surrounds the yoke at the state where the yoke is set to be positioned in the center, the outer circumferential portion is perpendicularly extensively formed in such a manner that a groove is formed therein and an externally communicating throughhole is formed in the groove corresponding to the incision portion of the yoke; and a vibration diaphragm in which the bobbin is supported and the outer circumferential portion is supported in the upper end of the frame, for generating an acoustic sound in correspondence to the drive signal when the bobbin is displaced up and down, wherein spaces in the incision portion of the yoke and the frame are formed of a magnitude of preventing a connection portion between the coil and lead wire from contacting the yoke during vertical vibration, to thereby extend an up-and-down vibration width of the bobbin.