Patent ID: 8411882

Claim:
An electronic device, comprising: a housing having an inner surface, an outer surface and a plurality of openings penetrating between the inner surface and the outer surface; a first electrical terminal and a second electrical terminal disposed on the inner surface of the housing; a circuit board having a third electrical terminal and a fourth electrical terminal disposed thereon; and an electro-acoustic transducer disposed on the inner surface of the housing and electrically connected to the circuit board, the electro-acoustic transducer comprising: a first electret diaphragm configured to vibrate and make sounds in accordance with a first electrical signal, the first electret diaphragm being positioned on the inner surface of the housing and having a first film body and a first electrode layer, wherein the first film body includes opposing upper and lower surfaces and has static charges, and the first electrode layer is formed on the lower surface of the first film body; a first conductive plate stacked on the upper surface of the first film body and having a plurality of openings, wherein the first electrode layer of the first electret diaphragm and the first conductive plate are electrically connected to receive the first electrical signal; and at least one first spacer disposed between the first electret diaphragm and the first conductive plate to keep a predetermined distance between the first electret diaphragm and the first conductive plate; wherein the third and fourth electrical terminals of circuit board are electrically connected to the first and second electrical terminals, respectively, for applying the first electrical signal to the first electrode layer of the first electret diaphragm and the first conductive plate, respectively.