MEMS MICROPHONE

• Main Authors: HORIMOTO YASUHIRO, OBI MITSUAKI, UCHIDA YUKI, KANO HAJIME, YOSHIDA TAKUMA, ITOYAMA TOSHITAKE
• Format: Patent
• Language: English; Japanese
• Published: 05.10.2023
• Subjects: DEAF-AID SETS; ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKEACOUSTIC ELECTROMECHANICAL TRANSDUCERS; PUBLIC ADDRESS SYSTEMS

To generate a differential signal whose phase is inverted while suppressing increase of circuit scale of a MEMS microphone.SOLUTION: A MEMS microphone includes: a diaphragm having conductivity; a first variable capacitor having a first fixed electrode facing to the diaphragm, whose capacitance changes according to vibration of the diaphragm; a second variable capacitor having a second fixed electrode facing to the diaphragm, whose capacitance changes according to vibration of the diaphragm; a first voltage output part for outputting a first voltage changes according to the change of the capacitance of the first variable capacitor; and a second voltage output part for outputting a second voltage changes according to the change of the capacitance of the second variable capacitor, a first bias voltage is applied to the first fixed electrode, a reference voltage is applied to the second fixed electrode, and a second bias voltage whose difference from the reference voltage is half of the difference between the first bias voltage and the reference voltage is applied to the diaphragm.SELECTED DRAWING: Figure 1 【課題】ＭＥＭＳマイクロフォンの回路規模の増大を抑制しつつ、位相が反転された差動信号を生成する。【解決手段】ＭＥＭＳマイクロフォンは、導電性を有する振動膜と、振動膜に対向する第１固定電極を有し、振動膜の振動に応じて静電容量が変化する第１可変キャパシタと、振動膜に対向する第２固定電極を有し、振動膜の振動に応じて静電容量が変化する第２可変キャパシタと、第１可変キャパシタの静電容量の変化に応じて変化する第１電圧を出力する第１電圧出力部と、第２可変キャパシタの静電容量の変化に応じて変化する第２電圧を出力する第２電圧出力部と、を有し、第１固定電極には、第１バイアス電圧が印加され、第２固定電極には、基準電圧が印加され、振動膜には、基準電圧との差が、第１バイアス電圧と基準電圧との差の半分である第２バイアス電圧が印加される。【選択図】図１