Capacitive microphone with integrated cavity

摘要

A capacitive microphone and method of fabricating the same are provided. One or more holes can be formed in a first printed circuit board (PCB). A diaphragm can be surface micro-machined onto an interior surface of the first PCB at a region having the one or more holes. Interface electronics can also be interconnected to the interior surface of the PCB. One or more spacer PCBs can be attached to a second PCB to the first PCB, such that appropriate interconnections between interconnect vias are made. The second PCB and first PCB with spacers in between can be attached so as to create a cavity in which the diaphragm and interface electronics are located.

主权项

1. A microphone, comprising:
a back plate fabricated on a portion of a printed circuit board; and a diaphragm positioned relative to the portion of the printed circuit board so as to form a first volume between the diaphragm and the back plate, wherein a front surface of the diaphragm is in contact with the first volume, wherein a back surface of the diaphragm is in contact with a second volume, wherein one of the first volume and the second volume is in low acoustic impedance contact with the ambient acoustic environment and the other of the first volume and the second volume is in high acoustical impedance contact with the ambient acoustic environment, wherein when the diaphragm flexes in response to acoustic pressure, an output signal related to the acoustic pressure on the diaphragm is produced; and an enclosure, wherein the first volume is within the enclosure; wherein the first volume is in high acoustic impedance contact with the ambient acoustic environment the second volume is in low acoustic impedance contact with the ambient acoustic environment; and wherein the enclosure comprises:
the printed circuit board;a bottom printed circuit board;one or more spacer printed circuit boards, wherein the printed circuit board, the one or more spacer printed circuit boards, and the bottom printed circuit board are attached to form the enclosure, wherein the diaphragm is within the enclosure.