WO2021031107A1 - 压电式 mems 麦克风 - Google Patents

压电式 mems 麦克风 Download PDF

Info

Publication number
WO2021031107A1
WO2021031107A1 PCT/CN2019/101518 CN2019101518W WO2021031107A1 WO 2021031107 A1 WO2021031107 A1 WO 2021031107A1 CN 2019101518 W CN2019101518 W CN 2019101518W WO 2021031107 A1 WO2021031107 A1 WO 2021031107A1
Authority
WO
WIPO (PCT)
Prior art keywords
diaphragm
piezoelectric
mems microphone
base
arm
Prior art date
Legal status (The legal status 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 status listed.)
Ceased
Application number
PCT/CN2019/101518
Other languages
English (en)
French (fr)
Inventor
段炼
张睿
陈志远
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
AAC Technologies Holdings Shenzhen Co Ltd
Original Assignee
AAC Acoustic Technologies Shenzhen Co Ltd
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 AAC Acoustic Technologies Shenzhen Co Ltd filed Critical AAC Acoustic Technologies Shenzhen Co Ltd
Publication of WO2021031107A1 publication Critical patent/WO2021031107A1/zh
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R19/00—Electrostatic transducers
    • H04R19/04—Microphones
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R7/00—Diaphragms for electromechanical transducers; Cones
    • H04R7/16—Mounting or tensioning of diaphragms or cones
    • H04R7/24—Tensioning by means acting directly on free portions of diaphragm or cone
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R17/00—Piezoelectric transducers; Electrostrictive transducers
    • H04R17/02—Microphones
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B3/00—Devices comprising flexible or deformable elements, e.g. comprising elastic tongues or membranes
    • B81B3/0064—Constitution or structural means for improving or controlling the physical properties of a device
    • B81B3/0067—Mechanical properties
    • B81B3/007—For controlling stiffness, e.g. ribs
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R7/00—Diaphragms for electromechanical transducers; Cones
    • H04R7/02—Diaphragms for electromechanical transducers; Cones characterised by the construction
    • H04R7/04—Plane diaphragms
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B2201/00—Specific applications of microelectromechanical systems
    • B81B2201/02—Sensors
    • B81B2201/0257—Microphones or microspeakers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B2203/00—Basic microelectromechanical structures
    • B81B2203/01—Suspended structures, i.e. structures allowing a movement
    • B81B2203/0127—Diaphragms, i.e. structures separating two media that can control the passage from one medium to another; Membranes, i.e. diaphragms with filtering function
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B2203/00—Basic microelectromechanical structures
    • B81B2203/03—Static structures
    • B81B2203/0315—Cavities
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R2201/00—Details of transducers, loudspeakers or microphones covered by H04R1/00 but not provided for in any of its subgroups
    • H04R2201/003—Mems transducers or their use

Definitions

  • the invention relates to the technical field of acoustic-electric conversion devices, in particular to a piezoelectric MEMS microphone.
  • MEMS microphone is an electro-acoustic transducer made by micro-machining technology, which has the characteristics of small size, good frequency response characteristics, and low noise. With the development of electronic devices toward compactness and thinness, MEMS microphones are increasingly used in these devices.
  • MEMS microphones are mainly divided into capacitive MEMS microphones and piezoelectric MEMS microphones.
  • Piezoelectric MEMS microphones have many advantages over traditional capacitive MEMS microphones, including dust resistance, water resistance, and higher maximum output sound pressure (AOP).
  • AOP maximum output sound pressure
  • the piezoelectric diaphragm of the piezoelectric MEMS microphone is composed of multiple diaphragms. One end of each diaphragm is connected to the substrate, and the other end adopts a cantilever beam structure.
  • the object of the present invention is to provide a piezoelectric MEMS microphone with a high resonance frequency.
  • the present invention provides a piezoelectric MEMS microphone, including a substrate with a cavity, a piezoelectric diaphragm mounted on the substrate, and a constraint connecting the substrate and the piezoelectric diaphragm
  • the base includes a ring-shaped base enclosing the cavity, a support column arranged in the cavity and spaced apart from the ring-shaped base, the piezoelectric diaphragm includes a plurality of diaphragms, each The diaphragm includes a fixed end connected to the support column and a free end suspended above the cavity. One end of the restricting member is fixedly connected to the free end, and the other end is not connected to the base. The part of the fixed end is connected.
  • one end of the restriction member is fixedly connected to the free end, and the other end is connected to the annular base.
  • the base further includes a plurality of support beams, one end of the support beam is connected to the support column, and the other end is connected to the annular base, thereby dividing the cavity into a plurality of sub-cavities.
  • one end of the restriction member is fixedly connected to the free end, and the other end is connected to the support beam.
  • the restraint is a rigid restraint.
  • the restraint is an elastic restraint
  • the restraint includes an elastic arm, a protruding part connected with the diaphragm, and a fixed post connected with the base. One end is connected with the protruding part, and the other end is connected with the fixing post.
  • the elastic arm includes an arc-shaped connecting arm, a first arm connected to the protruding portion, and a second arm connected to the fixed column, one end of the arc-shaped connecting arm is connected to The first arm is connected, and the other end is connected with the second arm.
  • each of the diaphragms is connected to two of the restraining members, and one of the restraining members is provided at each end of the diaphragm facing the annular base.
  • the projection profile of the free end in the direction perpendicular to the diaphragm is located within the projection profile of the subcavity in the direction perpendicular to the diaphragm.
  • the projection profile of the free end in the direction perpendicular to the diaphragm is the same as the projection profile of the corresponding subcavity in the direction perpendicular to the diaphragm.
  • the piezoelectric vibrating membrane near the fixed end can generate a voltage signal, and a restraining member is arranged between the substrate and the piezoelectric vibrating membrane.
  • the deformation of the diaphragm can be restricted, thereby improving the resonance frequency of the piezoelectric diaphragm and reducing the noise of the entire piezoelectric MEMS microphone.
  • FIG. 1 is a perspective view of a piezoelectric MEMS microphone provided by an embodiment of the present invention
  • Figure 2 is a partial enlarged schematic diagram of A in Figure 1;
  • FIG. 3 is an exploded view of a piezoelectric MEMS microphone provided by an embodiment of the present invention.
  • Fig. 4 is a perspective view of the restricting member provided on the diaphragm according to the embodiment of the present invention.
  • Fig. 5 is a partial enlarged schematic diagram of B in Fig. 4;
  • Figure 6 is a top view of a piezoelectric MEMS microphone provided by an embodiment of the present invention.
  • Figure 7 is a cross-sectional view at C-C in Figure 6;
  • Fig. 8 is a perspective view of a substrate provided by an embodiment of the present invention.
  • an element when an element is referred to as being “fixed on” or “disposed on” another element, the element may be directly on the other element or there may be a centering element at the same time.
  • an element When an element is referred to as being “connected” to another element, it can be directly connected to the other element or an intermediate element may also exist.
  • the embodiment of the present invention provides a piezoelectric MEMS microphone.
  • the piezoelectric MEMS microphone includes a substrate 10 with a cavity 11 and a piezoelectric diaphragm 20 mounted on the substrate 10, The electric diaphragm 20 is located above the cavity 11, and external sound signals are introduced from the sound hole, and the sound pressure causes the piezoelectric diaphragm 20 to deform and generate voltage changes, thereby perceiving acoustic signals.
  • the base 10 includes an annular base 12 surrounded by a cavity 11, a supporting column 13 arranged in the cavity 11 and spaced apart from the annular base 12, and a plurality of supporting columns 13 in the circumferential direction Support beams 14 are arranged at intervals. One end of the support beam 14 is connected to the support column 13, and the other end of the support beam 14 is connected to the annular base 12 to divide the cavity 11 into a plurality of sub-cavities 15.
  • the annular base 12 in this embodiment It can be a 360-degree closed ring or not a complete ring.
  • the piezoelectric MEMS microphone also includes a constraining member 30 connecting the substrate 10 and the piezoelectric diaphragm 20.
  • the piezoelectric diaphragm 20 includes a plurality of diaphragms 21 arranged at intervals.
  • the constraining member 30 and the diaphragm The sheets 21 are connected and erected above the annular base 12.
  • Each diaphragm 21 includes a fixed end 211 connected to the supporting column 13 and a free end 212 connected to the fixed end 211 and suspended above the sub-cavity 15, a restraining member One end of 30 is fixedly connected to the free end 212, and the other end of the restraining member 30 is connected to the part of the base 10 that is not connected to the fixed end 211, that is, the other end of the restraining member 30 can be connected to the annular base 12, or the other end of the restraining member 30 Connected to the support beam 14.
  • the restraining member 30 can prevent the residual stress in the diaphragm 21 from causing different degrees of edge warping, inward curling and other deformations of the diaphragm 21, and prevent the diaphragm 21 from having differences in low frequency attenuation.
  • each diaphragm 21 is connected to the two restraining members 30, and the two ends of the diaphragm 21 facing the annular base 12 are each provided with a restraining member 30, so that the diaphragm 21 can be changed when the diaphragm 21 vibrates. smooth.
  • the diaphragm 21 extends from the fixed end 211 toward the free end 212 in a form that the width dimension (that is, the size of the diaphragm 21 along the circumferential direction of the supporting column 13) gradually increases. In this way, under the action of sound pressure, the free end 212 drives the film The sheet 21 vibrates, and the part of the diaphragm 21 close to the fixed end 211 undergoes greater deformation under the action of the force and generates more electric charges. Therefore, its sensitivity can be further improved. In specific experiments, this structural design can increase the sensitivity value to more than -35dB without changing the MEMS chip and membrane structure of the same area, which is a significant improvement compared to the traditional structure's -43dB sensitivity.
  • a constraining member 30 is provided on the side of the free end 212 away from the fixed end 211.
  • the constraining member 30 can constrain the deformation of the diaphragm 21, thereby improving the resonance frequency of the piezoelectric diaphragm 20 and reducing the entire piezoelectric Noise from MEMS microphones.
  • the resonance frequency can generally reach 35kHz or more, but the sensitivity is significantly reduced ( ⁇ -44dB).
  • the restraint 30 here can be replaced with a rigid restraint according to actual needs.
  • the restraining member 30 is an elastic restraining member.
  • the restraining member 30 is connected with the annular base 12.
  • the restraining member 30 includes a protrusion 31, a fixed post 32 and an elastic arm 33.
  • the protrusion 31 is connected with the diaphragm 21,
  • the fixed post 32 is connected with the base 10, specifically, the fixed post 32 is connected with the annular base 12, one end of the elastic arm 33 is connected with the protrusion 31, the other end of the elastic arm 33 is connected with the fixed post 32, and the elastic arm 33 It includes a first arm 331, a second arm 332, and an arc-shaped connecting arm 333.
  • the first arm 331 is connected to the protrusion 31, the second arm 332 is connected to the fixed column 32, and one end of the arc-shaped connecting arm 333 is connected to The first arm 331 is connected, the other end of the arc-shaped connecting arm 333 is connected with the second arm 332, the first arm 331 and the second arm 332 are arranged in parallel, and the fixed post 32 passes through the elastic arm 33 and the protrusion 31 Connected to the free end 212, the elastic arm 33 and the protruding portion 31 are all suspended above the sub-cavity 15.
  • the deformation of the diaphragm 21 can be restrained by the restraining member 30.
  • the elastic coefficient of the constraining member 30 can be adjusted through the design of the piezoelectric diaphragm 20, thereby affecting the resonance frequency, sensitivity, and noise floor of the piezoelectric MEMS microphone.
  • the elastic coefficient of the restraining member 30 increases, the restraining effect becomes stronger, the resonance frequency will be significantly increased, the noise will be reduced, but the sensitivity will decrease; on the contrary, the elastic coefficient will decrease, the restraining effect will become weaker, and the resonance frequency will decrease, but the sensitivity will increase significantly.
  • the design should be based on the required sensitivity, signal-to-noise ratio and resonance frequency of the product.
  • a free end 212 is suspended above each sub-cavity 15.
  • the projection profile of the inner side wall of the ring base 12 in the direction perpendicular to the diaphragm 21 can be circular or polygonal.
  • the number of support beams 14 can be based on actual conditions. It needs to be set, and the specific number is not limited.
  • the number of the support beams 14 can be less than, equal to, or greater than the number of vertices of the polygon.
  • two or more free ends 212 may also be suspended above each sub-cavity 15, which may be specifically determined according to actual design requirements.
  • the number of sub-cavities 15 corresponds to the number of diaphragms 21, and the projection contour of the free end 212 in the direction perpendicular to the diaphragm 21 is located in the projection contour of the sub-cavity 15 in the direction perpendicular to the diaphragm 21 Inside, each sub-cavity 15 corresponds to a free end 212.
  • the projection profile of the free end 212 in the direction perpendicular to the diaphragm 21 is the same as the projection profile of the corresponding subcavity 15 in the direction perpendicular to the diaphragm 21, so that the piezoelectric diaphragm 20 can cover the cavity 11. Avoid excessively large spacing between the piezoelectric diaphragm 20 and the substrate 10, thereby affecting the sound effect.
  • the projection contours of the inner side wall of the annular base 12 and the outer side wall of the support column 13 in the direction perpendicular to the diaphragm 21 are both polygonal.
  • the diaphragm 21 is in the direction perpendicular to the diaphragm 21.
  • the projection profile on the top is trapezoidal, and the outer profile of the entire piezoelectric diaphragm 20 is a polygonal structure.
  • the shape of the base 10 is not limited to the above.
  • the projection contours of the inner side wall of the annular base 12 and the outer side wall of the support column 13 in the base 10 in the direction perpendicular to the diaphragm 21 can also be circular, and a single diaphragm
  • the projection profile of 21 in the direction perpendicular to the diaphragm 21 is fan-shaped.
  • one of the projection profile of the inner side wall of the annular base 12 in the direction perpendicular to the diaphragm 21 and the projection profile of the outer side wall of the support column 13 in the direction perpendicular to the diaphragm 21 is circular and the other is polygonal .
  • the restraint member 30 can effectively release the residual stress formed by the diaphragm 21 during the processing process, and the warpage deformation of the diaphragm 21 can be better controlled.
  • the maximum deformation is less than 50nm. The low-frequency attenuation effect of piezoelectric MEMS microphones can be ignored.
  • the specific design of the restraining member 30 is not limited, and any structure that can play the role of elastic connection and restraint is within the scope of this patent.
  • the number, position, and symmetry of the constraining member 30 are not limited, and can be determined jointly by the design of the cantilever diaphragm 21 and the parameter requirements of the piezoelectric MEMS microphone.
  • any design with one end connected to the base 10 and one end connected to the free vibration end of the diaphragm 21 is within the scope of this patent.
  • the free end 212 may be all other edges except the fixed end 211, including a side edge extending in the radial direction and an outer periphery extending in the circumferential direction.
  • the specific structure of the fixed end 211 and the diaphragm 21 is not limited, and the symmetry of the overall structure of the piezoelectric diaphragm 20 is also not limited.
  • the diaphragm 21 can be a symmetrical or asymmetrical polygon, and the side edges of the diaphragm 21 can be It can be a straight line or a curve, and the width of the free end 212 of the diaphragm 21 is greater than the width of the fixed end 211 of the diaphragm 21, which is within the scope of this patent.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Multimedia (AREA)
  • Mechanical Engineering (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Piezo-Electric Transducers For Audible Bands (AREA)
  • Electrostatic, Electromagnetic, Magneto- Strictive, And Variable-Resistance Transducers (AREA)
  • Micromachines (AREA)

Abstract

本发明提供一种压电式MEMS麦克风，包括具有腔体的基底、安装在基底上的压电振膜、以及连接基底和压电振膜的约束件，基底包括围设成腔体的环形底座、设于腔体内并与环形底座间隔设置的支撑柱，压电振膜包括多个膜片，每一膜片包括与支撑柱连接的固定端以及悬置于腔体上方的自由端，约束件的一端与自由端固定连接、另一端与基底上未连接固定端的部分连接。本发明的压电式MEMS麦克风，在声压的作用下，自由端发生振动，靠近固定端的压电振膜能产生电压信号，在基底和压电振膜之间设有约束件，该约束件可以对膜片的形变进行约束，进而改善压电振膜的谐振频率，降低整个压电式MEMS麦克风的噪音。

Description

压电式MEMS麦克风 技术领域
本发明涉及声电转换装置技术领域,具体涉及一种压电式MEMS麦克风。
 背景技术
MEMS麦克风是一种用微机械加工技术制作出来的电声换能器，其具有 体积小、频响特性好、噪声低等特点。随着电子设备朝向小巧化、薄型化发展，MEMS麦克风被越来越广泛地运用到这些设备上。
目前，MEMS麦克风主要分为电容式MEMS麦克风和压电式MEMS麦克风。压电式MEMS麦克风相比于传统的电容式MEMS麦克风具有很多优势，包括防尘性、防水性以及较高的最大输出声压（AOP）等。不同于电容式麦克风的压电振膜结构，压电式MEMS麦克风的压电振膜由多个膜片组成，每个膜片一端与基底相连，另一端采用了悬臂梁结构。
但是，由于压电式MEMS麦克风在工艺中存在残余应力，膜片会发生不同程度的边缘翘曲、内卷等形变，造成整个膜片在低频衰减存在差异，从而使得其谐振频率显著降低(<10kHz), 整个压电MEMS的噪声增大，不能满足用户需求。
因此，为了提升压电式MEMS麦克风的谐振频率，有必要提供一种新的压电式MEMS麦克风，对整体的结构进行改进，以解决上述问题。
 技术问题
本发明的目的在于提供一种具有高谐振频率的压电式MEMS麦克风。
 技术解决方案
本发明的技术方案如下：
为实现上述目的，本发明提供了一种压电式MEMS麦克风，包括具有腔体的基底、安装在所述基底上的压电振膜、以及连接所述基底和所述压电振膜的约束件，所述基底包括围设成所述腔体的环形底座、设于所述腔体内并与所述环形底座间隔设置的支撑柱，所述压电振膜包括多个膜片，每一所述膜片包括与所述支撑柱连接的固定端以及悬置于所述腔体上方的自由端，所述约束件的一端与所述自由端固定连接、另一端与所述基底上未连接所述固定端的部分连接。
作为一种改进方式，所述约束件的一端与所述自由端固定连接，另一端与所述环形底座连接。
作为一种改进方式，所述基底还包括若干个支撑梁，所述支撑梁的一端与所述支撑柱连接、另一端与所述环形底座连接从而将所述腔体分隔成若干个子腔体。
作为一种改进方式，所述约束件的一端与所述自由端固定连接、另一端与所述支撑梁连接。
作为一种改进方式，所述约束件为刚性约束件。
作为一种改进方式，所述约束件为弹性约束件，所述约束件包括弹性臂、与所述膜片相连接的凸出部以及与所述基底相连接的固定柱，所述弹性臂的一端与所述凸出部连接、另一端与所述固定柱连接。
作为一种改进方式，所述弹性臂包括弧形连接臂、与所述凸出部连接的第一支臂以及与所述固定柱连接的第二支臂，所述弧形连接臂的一端与所述第一支臂连接、另一端与所述第二支臂连接。
作为一种改进方式，每一所述膜片连接两所述约束件，所述膜片朝向所述环形底座一侧的两端各设置一个所述约束件。
作为一种改进方式，所述自由端在垂直于所述膜片方向上的投影轮廓位于所述子腔体在垂直于所述膜片方向上的投影轮廓以内。
作为一种改进方式，所述自由端在垂直于所述膜片方向上的投影轮廓与对应的所述子腔体在垂直于所述膜片方向上的投影轮廓形状相同。
 有益效果
本发明的有益效果在于：
本发明的压电式MEMS麦克风，在声压的作用下，自由端发生振动，靠近固定端的压电振膜能产生电压信号，在基底和压电振膜之间设有约束件，该约束件可以对膜片的形变进行约束，进而改善压电振膜的谐振频率，降低整个压电式MEMS麦克风的噪音。
 附图说明
图1为本发明实施例提供的压电式MEMS麦克风的立体图；
图2为图1中A处的局部放大示意图；
图3为本发明实施例提供的压电式MEMS麦克风的爆炸图；
图4为本发明实施例提供的约束件设于膜片上的立体图；
图5为图4中B处的局部放大示意图；
图6为本发明实施例提供的压电式MEMS麦克风的俯视图；
图7为图6中C-C处的剖视图；
图8为本发明实施例提供的基底的立体图。
图中：10、基底；11、腔体；12、环形底座；13、支撑柱；14、支撑梁；15、子腔体；20、压电振膜；21、膜片；211、固定端；212、自由端；30、约束件；31、凸出部；32、固定柱；33、弹性臂；331、第一支臂；332、第二支臂；333、弧形连接臂。
 本发明的实施方式
下面结合附图和实施方式对本发明作进一步说明。
需要说明的是，本发明实施例中所有方向性指示（诸如上、下、内、外、顶部、底部……）仅用于解释在某一特定姿态（如附图所示）下各部件之间的相对位置关系等，如果该特定姿态发生改变时，则该方向性指示也相应地随之改变。
还需要说明的是，当元件被称为“固定于”或“设置于”另一个元件上时，该元件可以直接在另一个元件上或者可能同时存在居中元件。当一个元件被称为“连接”另一个元件，它可以是直接连接另一个元件或者可能同时存在居中元件。
请参阅图1至图8，本发明的实施例提供了一种压电式MEMS麦克风，压电式MEMS麦克风包括具有腔体11的基底10和安装在基底10上的压电振膜20，压电振膜20位于腔体11上方，外部的声音信号从声孔中传入，声压引起压电振膜20形变，产生电压变化，从而感知声学信号。
请参阅图1至图3，基底10包括围设成腔体11的环形底座12、设于腔体11内并与环形底座12间隔设置的支撑柱13、以及若干个沿支撑柱13的周向间隔设置的支撑梁14，支撑梁14的一端与支撑柱13连接，支撑梁14的另一端与环形底座12连接从而将腔体11分隔成若干个子腔体15，本实施例中的环形底座12可以是一个360度封闭的环形，也可以不是一个完整的环形。
请进一步参阅图4至图7，压电式MEMS麦克风还包括连接基底10和压电振膜20的约束件30，压电振膜20包括多个间隔设置的膜片21，约束件30与膜片21相连接并架设于环形底座12的上方，每一膜片21包括与支撑柱13连接的固定端211以及与固定端211连接并悬置于子腔体15上方的自由端212，约束件30的一端与自由端212固定连接，约束件30的另一端与基底10上未连接固定端211的部分连接，即约束件30的另一端可以与环形底座12连接，或者约束件30的另一端与支撑梁14连接。该约束件30可避免膜片21内残余应力对膜片21所造成的不同程度的边缘翘曲、内卷等形变，防止膜片21在低频衰减时存在差异。作为优选地实施方式，每一膜片21都与两所述约束件30相连接，膜片21朝向环形底座12一侧的两端各设置有一个约束件30，以便于膜片21振动时更平稳。
膜片21以宽度尺寸（即膜片21沿支撑柱13的周向尺寸）逐渐增大的形式从固定端211朝向自由端212延伸设置，这样，在声压的作用下，自由端212带动膜片21发生振动，靠近固定端211的膜片21部分在力的作用下发生更大的形变进而产生较多的电荷，因此，其灵敏度可以进一步提高。在具体实验中，对于同样面积的MEMS芯片和膜层结构不发生改变的情况下，这一结构设计能够将灵敏度数值提升到-35dB以上，相对于传统结构的-43dB的灵敏度有着显著提升。同时，在自由端212之远离固定端211的一侧设有约束件30，该约束件30可以对膜片21的形变进行约束，进而改善压电振膜20的谐振频率，降低整个压电式MEMS麦克风的噪音。
特别的，如果约束件30是刚性约束件，谐振频率一般可以达到35kHz以上，但是灵敏度显著降低（<-44dB）,可以根据实际使用的需要将此处的约束件30更换为刚性约束件。
本实施例中约束件30为弹性约束件，约束件30与环形底座12相连接，约束件30包括凸出部31、固定柱32和弹性臂33，凸出部31与膜片21相连接，固定柱32与基底10相连接，具体地，固定柱32与环形底座12相连接，弹性臂33的一端与凸出部31连接，弹性臂33的另一端与固定柱32相连接，弹性臂33包括第一支臂331、第二支臂332和弧形连接臂333，第一支臂331与凸出部31连接，第二支臂332与固定柱32连接，弧形连接臂333的一端与第一支臂331连接，弧形连接臂333的另一端与第二支臂332连接，第一支臂331与第二支臂332为平行设置，固定柱32通过弹性臂33、凸出部31与自由端212连接，弹性臂33、凸出部31都悬置于子腔体15的上方，当膜片21发生振动或者应力形变时，可以通过约束件30对膜片21的形变进行约束。
约束件30的弹性系数可以通过压电振膜20结构的设计进行调节，进而影响压电式MEMS麦克风的谐振频率、灵敏度以及底噪。当约束件30的弹性系数提高，约束作用更强，谐振频率将显著提高，噪声降低，但是灵敏度会下降；反之，弹性系数降低，约束作用变弱，谐振频率减低，但是灵敏度有明显提升，实际设计中应该按照产品要求的灵敏度、信噪比和谐振频率等进行设计。
本实施例中每个子腔体15的上方悬置一个自由端212，环形底座12的内侧壁在垂直于膜片21方向上的投影轮廓可以为圆形或者多边形，支撑梁14的数量可根据实际需要进行设置，具体的数量不做限制，当环形底座12的内侧壁在垂直于膜片21方向上的投影轮廓为多边形时，支撑梁14的数量可以小于、等于或者大于多边形的顶点数。需要说明的是，每个子腔体15的上方也可以悬置两个或者两个以上的自由端212，具体根据实际设计需要而定。
作为优选地实施方式，子腔体15的数量与膜片21的数量对应，自由端212在垂直于膜片21方向上的投影轮廓位于子腔体15在垂直于膜片21方向上的投影轮廓以内，每个子腔体15内对应有一个自由端212。优选地，自由端212在垂直于膜片21方向上的投影轮廓与对应的子腔体15在垂直于膜片21方向上的投影轮廓形状相同，以便于压电振膜20能覆盖于腔体11，避免压电振膜20与基底10之间的间隔过大，从而影响发声效果。
请进一步参阅图8，具体地，环形底座12的内侧壁和支撑柱13的外侧壁在垂直于膜片21方向上的投影轮廓均为多边形，此时，膜片21在垂直于膜片21方向上的投影轮廓呈梯形，整个压电振膜20的外轮廓为多边形结构。
当然，基底10的形状并不仅限于上述所述，基底10中环形底座12的内侧壁和支撑柱13的外侧壁在垂直于膜片21方向上的投影轮廓也可均为圆形，单个膜片21在垂直于膜片21方向上的投影轮廓呈扇形。
或者，环形底座12的内侧壁在垂直于膜片21方向上的投影轮廓和支撑柱13的外侧壁在垂直于膜片21方向上的投影轮廓中的一者为圆形、另一者为多边形。
经过多次试验可知，约束件30可以有效地释放膜片21在加工工艺中形成的残余应力，膜片21的翘曲形变可以得到较好的控制，形变最大处<50nm，这一形变量对压电式MEMS麦克风的低频衰减影响可以忽略。
约束件30的具体设计不做限制，凡是能够起到弹性连接和约束作用的结构均在本专利范围之内。
约束件30的数量、位置和分布的对称性等均不做限制，可以由悬臂梁膜片21的设计和压电式MEMS麦克风的参数要求来共同决定。对于约束结构，凡是一端连接基底10，一端连接膜片21的自由振动端的设计均在本专利范围之内。自由端212可以是除去固定端211以外的其他所有边缘，包括沿径向延伸的侧边和沿周向延伸的外周边。
固定端211和膜片21的具体结构不做限制，且压电振膜20的整体结构的对称性也不做限制，膜片21可以是对称或者非对称的多边形，膜片21的侧边缘可以是直线也可以是曲线，而且膜片21的自由端212的宽度大于膜片21的固定端211的宽度均在本专利范围之内。
以上所述的仅是本发明的实施方式，在此应当指出，对于本领域的普通技术人员来说，在不脱离本发明创造构思的前提下，还可以做出改进，但这些均属于本发明的保护范围。

Claims (10)

  1. 一种压电式MEMS麦克风，其特征在于，包括具有腔体的基底、安装在所述基底上的压电振膜、以及连接所述基底和所述压电振膜的约束件，所述基底包括围设成所述腔体的环形底座、设于所述腔体内并与所述环形底座间隔设置的支撑柱，所述压电振膜包括多个膜片，每一所述膜片包括与所述支撑柱连接的固定端以及悬置于所述腔体上方的自由端，所述约束件的一端与所述自由端固定连接、另一端与所述基底上未连接所述固定端的部分连接。
  2. 根据权利要求1所述的压电式MEMS麦克风，其特征在于，所述约束件的一端与所述自由端固定连接，另一端与所述环形底座连接。
  3. 根据权利要求1所述的压电式MEMS麦克风，其特征在于，所述基底还包括若干个支撑梁，所述支撑梁的一端与所述支撑柱连接、另一端与所述环形底座连接从而将所述腔体分隔成若干个子腔体。
  4. 根据权利要求3所述的压电式MEMS麦克风，其特征在于，所述约束件的一端与所述自由端固定连接、另一端与所述支撑梁连接。
  5. 根据权利要求1-4任一项所述的压电式MEMS麦克风，其特征在于，所述约束件为刚性约束件。
  6. 根据权利要求1-4任一项所述的压电式MEMS麦克风，其特征在于，所述约束件为弹性约束件，所述约束件包括弹性臂、与所述膜片相连接的凸出部以及与所述基底相连接的固定柱，所述弹性臂的一端与所述凸出部连接、另一端与所述固定柱连接。
  7. 根据权利要求6所述的压电式MEMS麦克风，其特征在于，所述弹性臂包括弧形连接臂、与所述凸出部连接的第一支臂以及与所述固定柱连接的第二支臂，所述弧形连接臂的一端与所述第一支臂连接、另一端与所述第二支臂连接。
  8. 根据权利要求1所述的压电式MEMS麦克风，其特征在于，每一所述膜片连接两所述约束件，所述膜片朝向所述环形底座一侧的两端各设置一个所述约束件。
  9. 根据权利要求3所述的压电式MEMS麦克风，其特征在于，所述自由端在垂直于所述膜片方向上的投影轮廓位于所述子腔体在垂直于所述膜片方向上的投影轮廓以内。
  10. 根据权利要求3所述的压电式MEMS麦克风，其特征在于，所述自由端在垂直于所述膜片方向上的投影轮廓与对应的所述子腔体在垂直于所述膜片方向上的投影轮廓形状相同。
PCT/CN2019/101518 2019-08-16 2019-08-20 压电式 mems 麦克风 Ceased WO2021031107A1 (zh)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN201910760708.XA CN110650420B (zh) 2019-08-16 2019-08-16 压电式mems麦克风
CN201910760708.X 2019-08-16

Publications (1)

Publication Number Publication Date
WO2021031107A1 true WO2021031107A1 (zh) 2021-02-25

Family

ID=68990174

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2019/101518 Ceased WO2021031107A1 (zh) 2019-08-16 2019-08-20 压电式 mems 麦克风

Country Status (3)

Country Link
US (1) US11212617B2 (zh)
CN (1) CN110650420B (zh)
WO (1) WO2021031107A1 (zh)

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111294715B (zh) * 2020-03-02 2021-05-04 瑞声声学科技(深圳)有限公司 压电mems麦克风
CN111453691B (zh) * 2020-04-21 2023-05-12 安徽奥飞声学科技有限公司 一种mems结构的制造方法
CN114302294B (zh) * 2020-10-08 2024-10-29 阿比特电子科技股份有限公司 微机电系统声学传感器、微机电系统封装结构及其制造方法
CN214154838U (zh) * 2020-11-30 2021-09-07 瑞声科技（南京）有限公司 压电mems麦克风
CN112584289B (zh) * 2020-11-30 2022-03-08 瑞声新能源发展(常州)有限公司科教城分公司 一种压电式麦克风及其制作方法
CN113115188B (zh) * 2021-03-29 2023-07-04 瑞声声学科技(深圳)有限公司 Mems压电麦克风
US12328559B2 (en) 2021-06-17 2025-06-10 Skyworks Solutions, Inc. Acoustic devices with improved sensitivity
CN217985406U (zh) * 2022-06-21 2022-12-06 瑞声开泰科技(武汉)有限公司 一种mems压电扬声器
CN115567855B (zh) * 2022-09-23 2026-03-27 华中科技大学 一种压电mems扬声器及其性能提升方法
CN115442725A (zh) * 2022-10-09 2022-12-06 中国兵器工业集团第二一四研究所苏州研发中心 一种压电式mems麦克风结构及电子设备

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009065606A (ja) * 2007-09-10 2009-03-26 Yamaha Corp 振動トランスデューサ
CN108367908A (zh) * 2015-12-18 2018-08-03 罗伯特·博世有限公司 中心固定的mems麦克风膜
CN109495829A (zh) * 2018-12-31 2019-03-19 瑞声声学科技(深圳)有限公司 压电式mems麦克风
CN109587613A (zh) * 2018-12-31 2019-04-05 瑞声声学科技(深圳)有限公司 压电式麦克风

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002052893A1 (en) * 2000-12-22 2002-07-04 Brüel & Kjær Sound & Vibration Measurement A/S A highly stable micromachined capacitive transducer
JP2009089095A (ja) * 2007-09-28 2009-04-23 Yamaha Corp 振動トランスデューサ
CN101841758A (zh) * 2010-03-08 2010-09-22 瑞声声学科技(深圳)有限公司 电容mems麦克风
CN103460721B (zh) * 2011-03-31 2017-05-24 韦斯伯技术公司 具有间隙控制几何形状的声换能器以及声换能器制造方法
US9029963B2 (en) * 2012-09-25 2015-05-12 Sand 9, Inc. MEMS microphone
DE102015213772A1 (de) * 2015-07-22 2017-01-26 Robert Bosch Gmbh MEMS-Bauelement mit Membranelement, das über eine Federstruktur an den Bauelementschichtaufbau angebunden ist
DE102016111909B4 (de) * 2016-06-29 2020-08-13 Infineon Technologies Ag Mikromechanische Struktur und Verfahren zu ihrer Herstellung
CN107690114B (zh) * 2016-08-04 2023-10-03 共达电声股份有限公司 Mems麦克风振膜及mems麦克风
JP6830527B2 (ja) * 2017-05-09 2021-02-17 富士フイルム株式会社 圧電マイクロフォンチップおよび圧電マイクロフォン

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009065606A (ja) * 2007-09-10 2009-03-26 Yamaha Corp 振動トランスデューサ
CN108367908A (zh) * 2015-12-18 2018-08-03 罗伯特·博世有限公司 中心固定的mems麦克风膜
CN109495829A (zh) * 2018-12-31 2019-03-19 瑞声声学科技(深圳)有限公司 压电式mems麦克风
CN109587613A (zh) * 2018-12-31 2019-04-05 瑞声声学科技(深圳)有限公司 压电式麦克风

Also Published As

Publication number Publication date
CN110650420A (zh) 2020-01-03
US20210051409A1 (en) 2021-02-18
US11212617B2 (en) 2021-12-28
CN110650420B (zh) 2021-01-08

Similar Documents

Publication Publication Date Title
WO2021031107A1 (zh) 压电式 mems 麦克风
WO2021031104A1 (zh) 压电式 mems 麦克风
CN110545514B (zh) 压电式mems麦克风
US10993040B2 (en) Piezoelectric microphone
CN210609708U (zh) Mems麦克风和电子设备
US11057715B2 (en) Piezoelectric microphone
CN111328005B (zh) 压电式mems麦克风
WO2020140569A1 (zh) 压电式麦克风
JP2010187099A (ja) 収音装置
CN216752098U (zh) Mems麦克风芯片
US10123129B2 (en) MEMS device and process
CN102106158A (zh) 嵌套式复合扬声器驱动单元
WO2022007002A1 (zh) 一种压电式mems麦克风
CN212572962U (zh) 一种压电式mems麦克风
CN216752082U (zh) Mems麦克风芯片
CN112911470A (zh) 一种扬声器模组
CN214315604U (zh) Mems麦克风
CN110710228A (zh) 扬声器结构
CN113873413B (zh) 一种电容式传感器及麦克风
CN112261561B (zh) 一种mems发声装置
JP6253101B2 (ja) 動電型電気音響変換器、及びその振動板、並びに動電型電気音響変換器の製造方法
WO2018103310A1 (zh) 锥盆式的扬声器膜片和扬声器
CN105393557B (zh) 用于麦克风隔膜的稳定器和麦克风换能器的换能器组合件
CN218352721U (zh) 一种自动矫正滚振的电声转换器
CN222655322U (zh) 压电扬声器

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 19942554

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 19942554

Country of ref document: EP

Kind code of ref document: A1