WO2021134672A1 - Microphone mems piézoélectrique - Google Patents

Microphone mems piézoélectrique Download PDF

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Publication number
WO2021134672A1
WO2021134672A1 PCT/CN2019/130909 CN2019130909W WO2021134672A1 WO 2021134672 A1 WO2021134672 A1 WO 2021134672A1 CN 2019130909 W CN2019130909 W CN 2019130909W WO 2021134672 A1 WO2021134672 A1 WO 2021134672A1
Authority
WO
WIPO (PCT)
Prior art keywords
diaphragm
piezoelectric
mems microphone
elastic support
microphone according
Prior art date
Application number
PCT/CN2019/130909
Other languages
English (en)
Chinese (zh)
Inventor
童贝
石正雨
沈宇
李杨
Original Assignee
瑞声声学科技(深圳)有限公司
瑞声科技（南京）有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 瑞声声学科技(深圳)有限公司, 瑞声科技（南京）有限公司 filed Critical 瑞声声学科技(深圳)有限公司
Priority to PCT/CN2019/130909 priority Critical patent/WO2021134672A1/fr
Publication of WO2021134672A1 publication Critical patent/WO2021134672A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R1/00—Details of transducers, loudspeakers or microphones
    • H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
    • H04R1/22—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only 
    • H04R1/28—Transducer mountings or enclosures modified by provision of mechanical or acoustic impedances, e.g. resonator, damping means
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R17/00—Piezoelectric transducers; Electrostrictive transducers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R7/00—Diaphragms for electromechanical transducers; Cones
    • H04R7/16—Mounting or tensioning of diaphragms or cones

Definitions

  • the utility model relates to the field of microphones.
  • piezoelectric MEMS microphones mainly adopt the method of diaphragm bending or cantilever bending, which generates a certain stress at the anchor point, which causes the piezoelectric diaphragm covering it to be compressed, thereby generating a certain charge output.
  • the overall noise level is relatively high, and the signal-to-noise ratio can not be significantly improved by changing the thickness and stress of the film and optimizing the design of slots and holes on the diaphragm.
  • the purpose of the utility model is to provide a piezoelectric MEMS microphone with a high signal-to-noise ratio.
  • a piezoelectric MEMS microphone has a substrate with a back cavity, a diaphragm suspended in the back cavity, and an elastic support connected between the diaphragm and the substrate.
  • the diaphragm extends along the diaphragm.
  • a first piezoelectric diaphragm and a second piezoelectric diaphragm are respectively provided on both sides of the vibration direction, and the second piezoelectric diaphragm is connected in parallel with the first piezoelectric diaphragm.
  • first piezoelectric diaphragm and the second piezoelectric diaphragm have the same structure.
  • first piezoelectric diaphragm and the second piezoelectric diaphragm are directly opposite and symmetrically arranged on both sides of the vibrating diaphragm.
  • the first piezoelectric diaphragm is circular, rectangular or square.
  • the first piezoelectric membrane structure includes two electrode layers and a piezoelectric layer sandwiched between the two electrode layers.
  • the elastic support member extends from the edge of the diaphragm toward the base, and the base recesses corresponding to the elastic support member to form an escape portion, and the elastic support member is accommodated in the escape portion.
  • the elastic support includes an extension arm extending from the edge of the diaphragm toward the base and spaced apart from the base, and an end of the extension arm that is bent and extended away from the diaphragm and connected to the base.
  • the connecting wall of the substrate connection is not limited to.
  • connecting arms are respectively formed on opposite sides of the extension arm.
  • each of the connecting arms includes at least one connecting bar parallel to the extension arm.
  • At least two of the elastic support members are symmetrically connected to the outer circumference of the diaphragm.
  • the beneficial effect of the utility model is that the design mainly prepares the second piezoelectric diaphragm corresponding to the first piezoelectric diaphragm under the diaphragm, and the second piezoelectric diaphragm is connected in parallel with the first piezoelectric diaphragm.
  • the design method will slightly reduce the sensitivity, but because the capacitance is doubled after the parallel connection, the noise will be greatly reduced, so the overall signal-to-noise ratio (SNR) will be considerably improved.
  • Figure 1 is a schematic diagram of the structure of the piezoelectric MEMS microphone provided by the utility model
  • Figure 2 is a cross-sectional view taken along line A-A of Figure 1;
  • Figure 3 is a partial enlarged view of B in Figure 1;
  • Fig. 4 is a partial enlarged view of C in Fig. 1;
  • Fig. 5 is another embodiment of the piezoelectric MEMS microphone provided by the present invention.
  • Piezoelectric MEMS microphone 1. substrate; 101, back cavity; 2. diaphragm; 3. first piezoelectric diaphragm; 4. second piezoelectric diaphragm; 31, electrode layer; 32, piezoelectric layer; 5. Elastic support; 51, extension arm; 52, connecting arm; 521, connecting strip.
  • a piezoelectric MEMS microphone 100 which has a substrate with a back cavity 101, a diaphragm 2 suspended in the back cavity 101, and is connected between the diaphragm 2 and the substrate
  • the elastic support 5 of the diaphragm 2 is provided with a first piezoelectric diaphragm 3 and a second piezoelectric diaphragm 4 on both sides of the diaphragm 2 along the vibration direction of the diaphragm 2, and the second piezoelectric diaphragm 4 is connected in parallel with the first piezoelectric diaphragm 3.
  • the second piezoelectric diaphragm 4 opposite to the first piezoelectric diaphragm 3 is mainly prepared under the diaphragm 2, and the second piezoelectric diaphragm 4 is connected in parallel with the first piezoelectric diaphragm 3.
  • This design method will The sensitivity is slightly reduced, but the noise will be greatly reduced due to the increase of the capacitance after the parallel connection, so the overall signal-to-noise ratio (SNR) will be considerably improved.
  • the distance between the diaphragm 2 and the substrate 1 will change, and the first piezoelectric diaphragm 3 and the second piezoelectric diaphragm 4 will then generate electric charge output, thereby transferring the sound wave
  • the signal is converted into an electrical signal to realize the corresponding function of the microphone.
  • the first piezoelectric diaphragm 3 and the second piezoelectric diaphragm 4 have the same structure. Due to the same structure of the two, the capacitance is doubled after parallel connection, and the noise will be greatly reduced, so the overall signal-to-noise ratio (SNR) will be considerably improved.
  • SNR signal-to-noise ratio
  • the first piezoelectric diaphragm 3 and the second piezoelectric diaphragm 4 are directly opposite and symmetrically arranged on both sides of the diaphragm 2. Further reduce noise and improve signal-to-noise ratio (SNR).
  • SNR signal-to-noise ratio
  • the first piezoelectric diaphragm 3 is circular, rectangular or square. Please refer to FIG. 1, the first piezoelectric diaphragm 3 is in the shape of a strip and is arranged in two, and the two first piezoelectric diaphragms 3 are center-symmetrical and enclose a rectangle.
  • the structure of the first piezoelectric film 3 preferably includes two electrode layers 31 and a piezoelectric layer 32 sandwiched between the two electrode layers 31.
  • the two electrode layers 31 are one positive and one negative, so as to be connected to the piezoelectric layer 32.
  • the elastic support member 5 extends from the edge of the diaphragm 2 toward the direction of the base, the base 1 corresponds to the elastic support member 5 recessed to form an escape portion, the elastic support member 5 is accommodated in In the avoidance part, in this way, the compactness and consistency of the structure are good.
  • the elastic support member 5 includes an extension arm 51 extending from the edge of the diaphragm 2 toward the base and spaced apart from the base, and an end bent and extended from the extension arm 51 away from the diaphragm 2. And a connecting wall connected to the substrate.
  • the connecting arm 52 has elasticity, so that the diaphragm 2 can vibrate relative to the base.
  • the connecting arms 52 are formed on opposite sides of the extension arm 51, and the connecting arms 52 are symmetrically located on both sides of the end of the extension arm 51. In this way, the structure is compact and consistent. It is preferable that the two connecting arms 52 are in one. In a straight line.
  • each of the connecting arms 52 includes at least one connecting bar 521 parallel to the extension arm 51.
  • the connecting strips 521 are formed in an arcuate shape or a plurality of arcuate shapes, and the displacement between adjacent connecting strips 521 provides flexibility.
  • At least two of the elastic support members 5 are symmetrically connected to the outer periphery of the diaphragm 2 so that the diaphragm 2 is balanced in force.
  • the diaphragm 2 has a rectangular shape, and each of the four corners of the diaphragm 2 is provided with an elastic support member. 5.
  • the piezoelectric MENS microphone is not limited to a single model, and can also be made into an array structure of 2x2, 3x3, 4x4 or more.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Health & Medical Sciences (AREA)
  • Otolaryngology (AREA)
  • Multimedia (AREA)
  • Piezo-Electric Transducers For Audible Bands (AREA)

Abstract

L'invention concerne un microphone MEMS piézoélectrique, comprenant un substrat pourvu d'une cavité arrière, une membrane vibrante suspendue dans la cavité arrière, et une pièce de support élastique reliée entre la membrane vibrante et le substrat ; la membrane vibrante est fixée sur le substrat, deux côtés de la surface latérale de la membrane vibrante à l'opposé de la cavité arrière le long de la direction de vibration de la membrane vibrante sont respectivement pourvus d'une première membrane piézoélectrique, la surface latérale de la membrane vibrante faisant face à la cavité arrière est pourvue d'une seconde membrane piézoélectrique, et la seconde membrane piézoélectrique est connectée en parallèle à la première membrane piézoélectrique. Dans la présente conception, une structure correspondant à la seconde membrane piézoélectrique correspondant à la première membrane piézoélectrique au-dessus de la membrane vibrante est principalement préparée sous la membrane vibrante, et la seconde membrane piézoélectrique est connectée en parallèle avec la première membrane piézoélectrique. La conception réduit légèrement la sensibilité mais réduit significativement le bruit, puisque la capacité est doublée après la connexion parallèle, de telle sorte que le rapport signal sur bruit total (SNR) est considérablement augmenté.
PCT/CN2019/130909 2019-12-31 2019-12-31 Microphone mems piézoélectrique WO2021134672A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/CN2019/130909 WO2021134672A1 (fr) 2019-12-31 2019-12-31 Microphone mems piézoélectrique

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2019/130909 WO2021134672A1 (fr) 2019-12-31 2019-12-31 Microphone mems piézoélectrique

Publications (1)

Publication Number Publication Date
WO2021134672A1 true WO2021134672A1 (fr) 2021-07-08

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101931850A (zh) * 2008-12-31 2010-12-29 财团法人工业技术研究院 微型扬声器及其制造方法
CN102065354A (zh) * 2010-04-19 2011-05-18 瑞声声学科技(深圳)有限公司 振膜和包括该振膜的硅电容麦克风
US20120308066A1 (en) * 2011-06-03 2012-12-06 Hung-Jen Chen Combined micro-electro-mechanical systems microphone and method for manufacturing the same
CN106911990A (zh) * 2017-03-09 2017-06-30 歌尔股份有限公司 Mems声换能器及其制造方法
CN110381428A (zh) * 2019-08-30 2019-10-25 湖南捷力泰科技有限公司 新型压电扬声器

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101931850A (zh) * 2008-12-31 2010-12-29 财团法人工业技术研究院 微型扬声器及其制造方法
CN102065354A (zh) * 2010-04-19 2011-05-18 瑞声声学科技(深圳)有限公司 振膜和包括该振膜的硅电容麦克风
US20120308066A1 (en) * 2011-06-03 2012-12-06 Hung-Jen Chen Combined micro-electro-mechanical systems microphone and method for manufacturing the same
CN106911990A (zh) * 2017-03-09 2017-06-30 歌尔股份有限公司 Mems声换能器及其制造方法
CN110381428A (zh) * 2019-08-30 2019-10-25 湖南捷力泰科技有限公司 新型压电扬声器

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