Patent ID: 8345897
Filing Date: 2013-01-01
Classification: H04R

Abstract:
1. An electromagnetic conversion unit includes: at least two magnets each having both poles on the opposite faces thereof; a plurality of magnetic pole yokes that are each magnetized by one of the at least two magnets to establish a magnetic pole; and a vibrating membrane that is disposed between the at least two magnets and is electromagnetically coupled to the magnetic pole yokes by energizing a coil pattern formed on the surface of the membrane to vibrate in a predetermined direction, wherein the magnetic pole yokes each include an abutting section that abuts against one of the at least two magnets to be magnetized and a magnetic pole section for establishing the magnetic pole in a band shape, and wherein a plurality of magnetic pole sections of the plural magnetic pole yokes are disposed on the upper and lower sides of the vibrating membrane, and also the magnetic pole sections are disposed at a spacing such that the magnetic pole sections different from each other in magnetic polarity are positioned alternately in a lateral direction of the vibrating membrane to form magnetic pole faces on the upper and lower sides of the vibrating membrane.