US 7,577,269 B2
Acoustic transducer
Roger A. Adelman, Villa Hills, Ky. (US)
Assigned to Technology Properties Limited, Cupertino, Calif. (US)
Filed on Aug. 28, 2006, as Appl. No. 11/511,170.
Prior Publication US 2008/0049967 A1, Feb. 28, 2008
Int. Cl. H04R 1/00 (2006.01)
U.S. Cl. 381—417  [381/424] 22 Claims
OG exemplary drawing
 
1. An electro-magnetic transducer, comprising:
(a) a housing, the housing including a magnetic structure with at least a pair of magnetic poles of opposite polarity, the pair of magnetic poles creating a first area of magnetic flux concentration;
(b) a vibratable sound-producing member at least partially formed of magnetically permeable material, the sound-producing member having a first end rigidly affixed within the housing and a second vibratable end disposed in the first area of magnetic flux concentration;
(d) a coil positioned to induce a second magnetic field in the sound-producing member, the second end of the sound-producing member being vibratable toward and away from the magnetic poles to produce acoustic waves in the area of magnetic flux in response to electrical current passing through the coil; and
(e) an acoustic conduit for receiving sound waves generated by the sound-producing member and directing such waves from the area of magnetic flux concentration through at least one of the magnetic poles to a location outside the housing.