WO2023123129A1 - 一种压电感应单元、压电麦克风和终端 - Google Patents

一种压电感应单元、压电麦克风和终端 Download PDF

Info

Publication number
WO2023123129A1
WO2023123129A1 PCT/CN2021/142707 CN2021142707W WO2023123129A1 WO 2023123129 A1 WO2023123129 A1 WO 2023123129A1 CN 2021142707 W CN2021142707 W CN 2021142707W WO 2023123129 A1 WO2023123129 A1 WO 2023123129A1
Authority
WO
WIPO (PCT)
Prior art keywords
cantilever
piezoelectric
sensing unit
piezoelectric sensing
unit according
Prior art date
Application number
PCT/CN2021/142707
Other languages
English (en)
French (fr)
Inventor
邢增平
阮盛杰
Original Assignee
华为技术有限公司
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 华为技术有限公司 filed Critical 华为技术有限公司
Priority to PCT/CN2021/142707 priority Critical patent/WO2023123129A1/zh
Publication of WO2023123129A1 publication Critical patent/WO2023123129A1/zh

Links

Images

Classifications

    • 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
    • H04R17/02—Microphones

Definitions

  • the present application relates to the technical field of microphone structures, and in particular to a piezoelectric induction unit, a piezoelectric microphone and a terminal.
  • a microphone is a common sound capture device used to convert sound signals into electrical signals.
  • microphones include moving coil, aluminum ribbon, electret microphone (ECM), micro-electromechanical systems (MEMS) capacitive and MEMS piezoelectric, etc.
  • ECM electret microphone
  • MEMS micro-electromechanical systems
  • Modern microphones are more electret and MEMS condenser; however, electret microphones are far inferior to MEMS condenser microphones in terms of production consistency and temperature stability due to technological reasons.
  • MEMS condenser microphones need to use charge pumps to improve sensitivity, resulting in high power consumption.
  • the MEMS piezoelectric microphone has sound pressure, it can use the positive piezoelectric effect of the piezoelectric material to convert it into a charge output, and the power consumption is small.
  • the piezoelectric microphone in the prior art includes a base with a cavity, a cantilever is prepared on the region of the base with the cavity, and a piezoelectric material layer is prepared on the cantilever to form a piezoelectric sensing unit of the piezoelectric microphone.
  • the cantilever in the piezoelectric microphone in the prior art usually extends from the edge of the cavity to the center, or extends from the center of the cavity to the edge of the cavity, resulting in a relatively short length of the cantilever.
  • the relationship between the charge output of the microphone and the pressure on the cantilever has a strong correlation with the length of the cantilever. Therefore, the cantilever length of the piezoelectric microphone in the prior art is relatively short, resulting in a poor charge output effect of the microphone.
  • the present application provides a piezoelectric induction unit, a piezoelectric microphone and a terminal, so as to improve the signal-to-noise ratio of the piezoelectric microphone and improve the performance of the piezoelectric microphone.
  • the present application provides a piezoelectric sensing unit.
  • the piezoelectric sensing unit includes a base, an auxiliary layer, a central film, a piezoelectric film and a plurality of cantilevers.
  • the base has a cavity extending along the first direction, the cavity forms a polygonal opening on the first surface of the base, and the polygonal opening has adjacent first sides and second sides.
  • the auxiliary layer is formed on the first surface of the base, the auxiliary layer includes a first auxiliary portion, and the first auxiliary portion is located in a region of the first surface adjacent to the first side.
  • the cantilever is connected to the sides of the polygonal opening in one-to-one correspondence.
  • the cantilever includes a first end and a second end, the first end is connected to the first auxiliary part, and the first end is connected to the first auxiliary part.
  • the connection point is located on the side of the first auxiliary part close to the second side.
  • the above-mentioned cantilever extends along the extension direction of the second side, so in this solution, the length of the cantilever is longer, which is beneficial to improve the signal-to-noise ratio of the piezoelectric microphone.
  • the central membrane is connected to the second end of each cantilever, and the orthographic projection of the polygonal opening on the first plane completely covers the orthographic projection of the central membrane on the first plane, and the first plane is perpendicular to the first direction.
  • the above-mentioned central membrane is opposite to the cavity of the base, and after the sound wave enters the cavity, it can drive the central membrane to vibrate, and then drive the cantilever to swing.
  • the piezoelectric film is arranged on the surface of the cantilever. Specifically, the piezoelectric film includes a piezoelectric material layer, a first electrode layer, and a second electrode layer, and the piezoelectric material layer connects the first electrode layer and the second electrode layer. Then, the piezoelectric film The swing of the cantilever can be converted into an electrical signal.
  • the cantilever includes a first edge and a second edge, and the first edge and the second edge are connected between the first end and the second end. At least one of the first edge and the second edge is parallel to the second side of the polygon.
  • the central membrane and the cantilever can be integrally formed. This solution facilitates the simplification of the manufacturing process of the piezoelectric sensing unit, and also improves the reliability of the connection between the central membrane and the cantilever.
  • the above-mentioned central membrane may be provided with openings.
  • the number and shape of the openings are not limited.
  • the above-mentioned openings in the central membrane can release part of the sound pressure, thereby increasing the acoustic overload point of the piezoelectric induction unit.
  • the central membrane and the cantilever can be located on the same plane, or the central membrane and the cantilever can be located on different planes.
  • the central membrane and the cantilever can be located on the side of the cantilever facing the base, and the central membrane is connected to the cantilever through the connecting portion.
  • the above-mentioned central membrane and the cantilever are arranged on different planes, at least part of the structure of the above-mentioned central membrane can be overlapped with the cantilever, and the area of the central membrane can be made larger to increase the effective input sound pressure and improve the piezoelectric microphone. performance.
  • the above connecting part may specifically include a first connecting part and a second connecting part, the first connecting part may be integrally formed with the cantilever, and the second connecting part connects the first connecting part and the central membrane.
  • the first connection part may have a plurality of first connection holes, and the second connection part is connected to the above-mentioned first connection holes. Therefore, the connection reliability between the first connection part and the second connection part is improved.
  • the above-mentioned second connecting portion may also be connected to the cantilever, so that the central membrane is connected to the cantilever.
  • the cantilever can include at least one second connection hole, and the second connection part is connected to the second connection hole. This solution can improve the strength of the connection between the central membrane and the cantilever, and is also conducive to keeping the central membrane in an unfolded state.
  • the width of the cantilever along the direction perpendicular to the second edge can be the first width.
  • the above-mentioned first width gradually decreases from the first end to the second end.
  • the width of the connection between the cantilever and the first auxiliary part is relatively large, so that the stress near the first end of the cantilever is relatively large, which is conducive to converting vibration generated by sound waves into electrical signals and improving signal conversion efficiency.
  • the area of the central membrane can be designed larger, which can increase the effective input sound pressure and improve the performance of the piezoelectric microphone.
  • the first edge and/or the second edge of the cantilever is perpendicular to the first side connected to the cantilever. That is to say, at least one of the first edge and the second edge is perpendicular to the first side, so the solution can make the cantilever perpendicular to the first side, so as to reduce the torque at the root of the cantilever.
  • the first side of the inner cavity of the above-mentioned base may have a groove or a protrusion corresponding to the cantilever. It is worth noting that the above-mentioned first side may have a groove, which is beneficial to increase the length of the cantilever.
  • the effective area of the piezoelectric film is located on the side of the cantilever close to the first auxiliary part connected to the cantilever. Since the stress in the area where the cantilever is connected to the first connecting part is relatively large, the signal conversion efficiency can be improved and the performance of the piezoelectric microphone can be improved.
  • the above-mentioned central membrane can also have an additional mass block, which can make the central membrane swing larger when it is subjected to sound pressure, so as to improve the sensitivity of the piezoelectric sensing unit.
  • the lengths of the plurality of cantilevers of the piezoelectric sensing unit may be the same or different, which is not limited in this application.
  • the plurality of cantilevers have different lengths.
  • the piezoelectric microphone can have different low-frequency resonance points, and the low-frequency sensitivity is high, thereby improving the recognition ability of the voiceprint.
  • the material of the above-mentioned cantilever is not limited.
  • the material of the above-mentioned cantilever can be different from the piezoelectric material layer, and only serves as a structural layer, and only includes one piezoelectric material layer.
  • the piezoelectric sensing unit is a piezoelectric sensing unit in a single piezoelectric layer cantilever beam (Unimorph) mode.
  • the material of the above-mentioned cantilever can also be the same as that of the piezoelectric material layer, that is to say, the cantilever itself also works as a piezoelectric material layer.
  • the piezoelectric sensing unit is a piezoelectric sensing unit in a double piezoelectric layer cantilever beam (Bimorph) mode.
  • the auxiliary layer and the cantilever can be integrally formed. On the one hand, it facilitates the preparation of the auxiliary layer and the cantilever, and simplifies the preparation process. On the other hand, it is beneficial to improve the reliability of the connection between the auxiliary layer and the cantilever.
  • the present application also provides a piezoelectric microphone, which includes a circuit board, a chip, and the piezoelectric sensing unit in the first aspect.
  • the above-mentioned chip is arranged on the circuit board, and the first electrode and the second electrode are connected to the chip, so that the electrical signal converted from the sound wave by the piezoelectric induction unit can be processed.
  • the piezoelectric microphone further includes a housing, and the circuit board, the chip and the piezoelectric sensing unit are arranged inside the housing.
  • the shell can protect the internal circuit board, chip and piezoelectric induction unit, and can also shield interference.
  • the present application further provides a terminal, which includes the piezoelectric microphone of the second aspect above.
  • the radio effect of this terminal is better.
  • the specific types of the above-mentioned terminals are not limited.
  • the above-mentioned terminals can be mobile phones, earphones, smart devices, recording pens, hearing aids, microphones, voice-activated devices, or vehicle-mounted voice interaction devices that need to record sound.
  • FIG. 1 is a schematic structural diagram of a piezoelectric microphone in an embodiment of the present application
  • FIG. 2 is another structural schematic diagram of a piezoelectric microphone in an embodiment of the present application
  • Fig. 3 is a schematic top view structure of the piezoelectric sensing unit in the embodiment of the present application.
  • FIG. 4 is a schematic diagram of a lateral cross-sectional structure of a piezoelectric sensing unit in an embodiment of the present application
  • FIG. 5 is a schematic diagram of another top view structure of the piezoelectric sensing unit in the embodiment of the present application.
  • Fig. 6 is a schematic diagram of another top view structure of the piezoelectric sensing unit in the embodiment of the present application.
  • Fig. 7 is a schematic diagram of another top view structure of the piezoelectric sensing unit in the embodiment of the present application.
  • Fig. 8 is a schematic diagram of another lateral cross-sectional structure of the piezoelectric sensing unit in the embodiment of the present application.
  • FIG. 9 is a schematic diagram of another lateral cross-sectional structure of the piezoelectric sensing unit in the embodiment of the present application.
  • FIG. 10 is another schematic top view of the piezoelectric sensing unit in the embodiment of the present application.
  • Fig. 11 is a schematic diagram of another lateral cross-sectional structure of the piezoelectric sensing unit in the embodiment of the present application.
  • Fig. 12 is another top view structural schematic diagram of the piezoelectric sensing unit in the embodiment of the present application.
  • Fig. 13 is a schematic diagram of another lateral cross-sectional structure of the piezoelectric sensing unit in the embodiment of the present application.
  • Fig. 14 is a schematic diagram of another lateral cross-sectional structure of the piezoelectric sensing unit in the embodiment of the present application.
  • FIG. 15 is a schematic diagram of another lateral cross-sectional structure of the piezoelectric sensing unit in the embodiment of the present application.
  • the piezoelectric sensing unit, the piezoelectric microphone and the terminal are provided in the embodiments of the present application.
  • the following introduces its application scenarios.
  • the microphone is currently used in various terminals to realize functions such as calling or voice control of the terminal.
  • the types of microphones are also gradually changing, and MEMS piezoelectric microphones are an important research direction for those skilled in the art because of their low power consumption.
  • the cantilever of the existing piezoelectric microphone usually extends from the edge of the cavity to the center, or extends from the center of the cavity to the edge of the cavity, resulting in a relatively short length of the cantilever.
  • the relationship between the charge output of the microphone and the pressure on the cantilever has a strong correlation with the length of the cantilever. Therefore, the cantilever length of the piezoelectric microphone in the prior art is relatively short, resulting in a poor charge output effect of the microphone.
  • the present application provides a terminal, the terminal includes a piezoelectric microphone, and the piezoelectric microphone is used to record sound.
  • the specific types of the above-mentioned terminals are not limited.
  • the above-mentioned terminals can be mobile phones, earphones, smart devices, recording pens, hearing aids, microphones, voice-activated devices, or vehicle-mounted voice interaction devices that need to record sound.
  • FIG. 1 is a schematic structural diagram of a piezoelectric microphone in the embodiment of the present application.
  • the piezoelectric microphone in the embodiment of the present application includes a circuit board 1 , a chip 2 and a piezoelectric sensing unit 3 .
  • the aforementioned chip 2 is disposed on the circuit board 1 , specifically, the chip 2 may be electrically connected to the circuit board 1 .
  • the above-mentioned piezoelectric sensing unit 3 includes a base 31 and a cantilever 32 and a piezoelectric film (not shown) formed with the base 31, the above-mentioned base 31 has a cavity 311, the first end 321 of the cantilever 32 is connected to the The base 31 is connected to and suspended from the cavity 311 , and the piezoelectric film is disposed on the surface of the cantilever 32 .
  • the above-mentioned piezoelectric film can receive the vibration of the sound wave and convert it into an electric signal.
  • the piezoelectric film of the piezoelectric sensing unit 3 is electrically connected to the chip 2 , so that the chip 2 can process the electrical signal generated by the piezoelectric sensing unit 3 after receiving sound waves.
  • the chip 2 collects, amplifies, and filters the electrical signals, and then outputs analog signals or digital signals.
  • the positive piezoelectric characteristics of the piezoelectric material layer in the piezoelectric film can be used to convert the sound wave into an electrical signal without configuring other drivers, which is beneficial to reduce the volume of the piezoelectric microphone and reduce the pressure of the piezoelectric microphone.
  • the power consumption is beneficial to increase the service life of the piezoelectric microphone, thereby increasing the service life of the terminal with the piezoelectric microphone.
  • the above-mentioned piezoelectric microphone may further include a housing 4 .
  • the above-mentioned circuit board 1, chip 2 and piezoelectric sensing unit 3 are arranged inside the above-mentioned casing 4, and the above-mentioned casing 4 can shield interference signals, and can protect devices arranged inside the above-mentioned casing.
  • the piezoelectric microphone in the embodiment shown in FIG. 1 is a piezoelectric microphone packaged with a bottom opening, and the piezoelectric microphone packaged with a bottom opening is suitable for thin products.
  • the piezoelectric sensing unit 3 and the chip 2 are installed on the circuit board 1 respectively, and the area of the circuit board 1 opposite to the cavity 311 of the piezoelectric sensing unit 3 has an opening, which corresponds to the sound inlet. In this packaging method, it is not necessary to provide an opening in the case 4 .
  • FIG. 2 is another schematic structural diagram of a piezoelectric microphone in an embodiment of the present application.
  • the piezoelectric microphone in the embodiment shown in FIG. 2 is a top-open packaged piezoelectric microphone.
  • the piezoelectric sensing unit 3 and the chip 2 are installed on the circuit board 1 respectively, but the circuit board 1 has no opening, but the shell 4 has an opening, and the opening of the shell 4 serves as the sound inlet hole.
  • FIG. 3 is a top view structural diagram of the piezoelectric sensing unit in the embodiment of the present application
  • FIG. 4 is a side cross-sectional structural schematic diagram of the piezoelectric sensing unit in the embodiment of the present application.
  • the above-mentioned FIG. 4 is a schematic cross-sectional structural diagram at A-A in FIG. 3 .
  • the piezoelectric sensing unit 3 includes a base 31 , an auxiliary layer 36 , a plurality of cantilevers 32 , a central film 37 and a piezoelectric film 33 .
  • the base 31 is an integral support of the piezoelectric induction unit 3 , and the base 31 is formed with a cavity 311 extending along the first direction X, and the cavity 311 can form a cavity for sound transmission.
  • the above-mentioned cavity 311 is a tubular structure, has sidewalls that are hermetically connected around the periphery, and is formed with opposite first openings and second openings. The direction from the first opening to the second opening can be regarded as the first direction X.
  • the cavity 311 forms a polygonal opening 313 on the first surface 312 of the base 31 , or it can also be said that the base 31 has a polygonal opening 313 on the first surface 312 , and the polygonal opening 313 is the opening of the cavity 311 .
  • the auxiliary layer 36 is formed on the first surface 312 of the base 31 and can be used to connect the plurality of cantilevers 32 mentioned above. Specifically, it can be considered that the above-mentioned polygonal opening 313 includes adjacent first sides 3131 and second sides 3132 , and the auxiliary layer 36 includes a first auxiliary portion 361 located between the first surface 312 of the base 31 and the second side.
  • the area adjacent to one side 3131 that is to say, the first surface 312 of the base 31 corresponding to the first side 3131 is provided with the first auxiliary portion 361 .
  • the plurality of cantilever arms 32 are in one-to-one correspondence with the sides of the polygonal opening 313 .
  • the cantilever 32 includes opposite first end portion 321 and second end portion 322, wherein the first end portion 321 is connected to the side of the first auxiliary portion 361 close to the second side 3132, and the cantilever 32 extends along the second side 3132 direction extension.
  • the above-mentioned central membrane 37 is connected to the second end 322 of each cantilever 32 , then the central membrane 37 vibrates when receiving sound waves, and can drive the cantilever 32 to vibrate.
  • the orthographic projection of the polygonal opening 313 on the first plane completely covers the orthographic projection of the central membrane 37 on the first plane, and the first plane is perpendicular to the first direction X.
  • the central membrane 37 can move freely in the cavity 311 of the base 31 so as to vibrate under the drive of sound waves.
  • the above-mentioned piezoelectric film 33 is arranged on the surface of the cantilever 32, and the piezoelectric film 33 includes a piezoelectric material layer 331, a first electrode layer 332 and a second electrode layer 333, and the piezoelectric material layer 331 connects the first electrode layer 332 and the second electrode layer 333. Two electrode layers 333 .
  • the piezoelectric material layer 331 has piezoelectric properties.
  • the piezoelectric material layer 331 When physical deformation occurs, charges will be generated, and the strength of the charges is related to the strength of the deformation. Therefore, as the cantilever 32 vibrates, the piezoelectric material layer 331 generates charges, which can be transmitted through the first electrode layer 332 and the second electrode layer 333 to convert the acoustic signal into an electrical signal.
  • the first end 321 of the cantilever 32 is connected to the first auxiliary part 361 adjacent to the first side 3131, and the specific connection point between the cantilever 32 and the first auxiliary part 361 is close to the direction of the second side 3132, And the cantilever 32 extends along the extending direction of the second side 3132 , so the length of the cantilever 32 can reach a maximum length close to the length of the second side 3132 .
  • This solution can make full use of the opening space of the cavity 311 , so that the length of the cantilever 32 is longer.
  • the piezoelectric sensing unit 3 in the embodiment of the present application may be a piezoelectric sensing unit in a single piezoelectric layer cantilever beam (Unimorph) mode, or a piezoelectric sensing unit in a double piezoelectric layer cantilever beam (Bimorph) mode.
  • OPT SNR ⁇ 10 Log(OPT)
  • SNR cantilever beam signal-to-noise ratio
  • ⁇ is the dielectric constant
  • tan( ⁇ ) is the dielectric loss
  • d 31 is the piezoelectric constant
  • w is the width of the cantilever 32
  • L is the length of the cantilever 32
  • t is the thickness of the cantilever 32
  • q uni is the ratio of structural parameters .
  • the plurality of cantilevers 32 correspond to the sides of the polygonal opening 313 one by one, and each side of the polygonal opening 313 can be understood as the first side 3131 under different benchmarks.
  • each side of the auxiliary layer 36 and the polygonal The area adjacent to the side is also formed as the first auxiliary part 361 along with the understanding of the first side 3131 . That is, based on which cantilever 32 , the auxiliary layer 36 connected to the cantilever 32 is the first auxiliary portion 361 , and the side of the polygon adjacent to the first auxiliary portion 361 is the first side 3131 .
  • each side of the polygonal opening 313 may be formed as the first side 3131 , and the portion of the auxiliary layer 36 opposite to the polygonal opening 313 may be the first auxiliary portion 361 .
  • the above-mentioned piezoelectric sensing unit 3 can also include a first electrode 34 and a second electrode 35, the first electrode layer 332 of the piezoelectric film 33 of each cantilever 32 is connected with the first electrode 34, each cantilever 32
  • the second electrode layer 333 of the piezoelectric film 33 is connected to the second electrode 35 . It is worth noting that the first electrode layers 332 can be connected in series or in parallel, and the second electrode layers 333 can be connected in series or in parallel. design.
  • the piezoelectric sensing unit 3 in the embodiment of the present application can be a piezoelectric sensing unit in a single piezoelectric layer cantilever beam (Unimorph) mode, or can be a piezoelectric sensing unit in a double piezoelectric layer cantilever beam (Bimorph) mode Piezoelectric sensing unit.
  • the piezoelectric sensing unit 3 is a Unimorph mode piezoelectric sensing unit
  • the cantilever 32 is the base material, and the material of the cantilever 32 is different from that of the piezoelectric material layer, for example, it can be made of silicon-containing material.
  • the material of the cantilever 32 is the same as that of the piezoelectric material layer, that is, the cantilever itself is also used as the piezoelectric material layer.
  • the cantilever 32 can also be used as the base material, and two piezoelectric material layers are arranged on the surface of the cantilever to form a piezoelectric sensing unit in Bimorph mode.
  • the cantilever 32 includes a first edge 323 and a second edge 324 opposite to each other, and the first edge 323 and the second edge 324 are respectively connected between the first end portion 321 and the second end portion 322 . At least one of the first edge 323 and the second edge 324 is parallel to the second side 3132 of the polygonal opening 313 .
  • This embodiment can make the length of the cantilever 32 close to the length of the second side 3132, that is to say, the length of the cantilever 32 can be made longer, and the area in the middle area of the polygonal opening 313 is less occupied, so that the area of the central membrane 37 Larger, it is beneficial to increase the effective input sound pressure. This solution can make full use of the area of the polygonal opening 313 to improve the performance of the piezoelectric microphone.
  • the first edge 323 and the second edge 324 can be made parallel, and then the first edge 323 and the second edge 324 are both parallel to the second edge 3132 .
  • FIG. 5 and FIG. 6 two other top view structural diagrams of the piezoelectric sensing unit are shown.
  • the first edge 323 and the second edge 324 can also be made non-parallel, and only the The first edge 323 is parallel to the second side 3132 , while the second edge 324 is not parallel to the second side 3132 .
  • the width of the cantilever 32 along the direction perpendicular to the second edge 3132 is the first width d
  • the above-mentioned first width d can be changed from the cantilever 32 gradually increases from the first end 321 to the second end 322.
  • the width of the connection between the cantilever 32 and the first auxiliary part 361 is small, more space can be reserved for the adjacent cantilever 32, which is beneficial to increase the length of the cantilever 32, thereby improving OPT and SNR.
  • the width of the cantilever 32 along the direction perpendicular to the second side 3132 is the first width d
  • the above-mentioned first width d can be obtained from the cantilever 32 gradually decreases from the first end 321 to the second end 322.
  • the width of the connection between the cantilever 32 and the first auxiliary portion 361 is relatively large, because the stress near the first end 321 of the cantilever 32 is relatively large. Therefore, this embodiment can increase the area of the cantilever 32 where the stress is greater, which is beneficial to convert the vibration generated by the sound wave into an electrical signal and improve the signal conversion efficiency.
  • the area of the central membrane 37 can be designed to be large, which can increase the effective input sound pressure and improve the performance of the piezoelectric microphone.
  • this embodiment can make the cantilever 32 perpendicular to the first side 3131, then during the vibration process of the cantilever 32, the connection between the first end 321 and the first auxiliary part 361 is less prone to torque, which is conducive to the formation of effective charges output.
  • FIG. 7 is another top view structural diagram of the piezoelectric sensing unit in the embodiment of the present application. It is worth noting that, in order to facilitate the expression of features, FIG. 7 simplifies some of the features of the drawing, and only shows the two-layer structure of the auxiliary layer 36 and the cantilever 32 . As shown in Figure 7, since the first side 3131 and the second side 3132 are not necessarily perpendicular, in other words, the polygonal opening is not necessarily a square opening, and may also be other polygonal openings such as triangular openings or pentagonal openings, as shown in Figure 7 The shown polygonal opening of the piezoelectric sensing unit is a triangular opening.
  • the first side 3131 can have a protrusion or a groove 3133 corresponding to the cantilever 32 . That is to say, the cantilever 32 is connected with the first auxiliary part 361 corresponding to the position of the protrusion and the groove 3133, and at least one of the first edge 323 and the second edge 324 is guaranteed to be perpendicular to the first side connected to the cantilever 32. 3131.
  • the first side 3131 can have a groove 3133 , so as to facilitate the lengthening of the cantilever 32 .
  • FIG. 8 is a schematic diagram of another lateral cross-sectional structure of the piezoelectric sensing unit in the embodiment of the present application.
  • the effective working area 334 of the piezoelectric film 33 can be located on the side of the cantilever 32 close to the first auxiliary part 361 connected to the cantilever 32 . That is to say, the effective working area 334 of the piezoelectric film 33 is located near the root of the cantilever 32 .
  • the effective working area 334 of the piezoelectric film 33 is located here, which can improve the signal conversion efficiency and improve the performance of the piezoelectric microphone. performance.
  • the aforementioned effective working area 334 refers to the area where the piezoelectric film 33 can convert the deformation of the piezoelectric material layer 331 into electrical signals.
  • the piezoelectric film 33 may have regions of the first electrode layer 332 , the piezoelectric material layer 331 and the second electrode layer 333 at the same time.
  • the entire piezoelectric film 33 may be located on a side of the cantilever 32 close to the first auxiliary part 361 connected to the cantilever 32 , as shown in FIGS. 6 and 8 .
  • FIG. 9 is a schematic diagram of another lateral cross-sectional structure of the piezoelectric sensing unit in the embodiment of the present application.
  • only at least one of the first electrode layer 332 and the second electrode layer 333 can be arranged on a side of the cantilever 32 close to the first auxiliary part 361 connected to the cantilever 32 .
  • the piezoelectric material layer 331 covers the entire cantilever 32 , this solution can simplify the manufacturing process of the piezoelectric film 33 .
  • the piezoelectric film 33 may also completely cover the entire cantilever 32 , which is not limited in the present application.
  • the specific preparation methods of the first electrode layer 332 and the second electrode layer 333 are not limited.
  • the first electrode layer 332 and the second electrode layer 333 can be arranged on The two side surfaces of the piezoelectric material layer 331 , that is, the first electrode layer 332 , the piezoelectric material layer 331 and the second electrode layer 333 are stacked in sequence.
  • the above-mentioned first electrode layer 332 and second electrode layer 333 are formed as interdigital electrodes.
  • the first electrode layer 332 and the second electrode layer 333 can be located on the piezoelectric material layer 331 on the same side surface.
  • first electrode layer 332, piezoelectric material layer 331 and second electrode layer 333 may also be stacked in sequence, indicating that the first electrode layer 332 is an interdigitated structure, and the second electrode layer 333 It is an interdigitated structure, which is not limited in the present application.
  • the auxiliary layer 36 and the cantilever 32 can be integrated.
  • this solution facilitates the preparation of the above-mentioned auxiliary layer 36 and the cantilever 32 , and the auxiliary layer 36 and the cantilever 32 can be formed in one process, thereby simplifying the preparation process.
  • the connection between the cantilever 32 and the auxiliary layer 36 can be made more reliable, thereby improving the structural reliability of the piezoelectric sensing unit 3 .
  • the above-mentioned central membrane 37 and the cantilever 32 can also be integrally formed.
  • this solution facilitates the preparation of the central membrane 37 and the cantilever 32 , and the central membrane 37 and the cantilever 32 can be formed in one process, thereby simplifying the manufacturing process.
  • the connection between the cantilever 32 and the central membrane 37 can be made more reliable, thereby improving the structural reliability of the piezoelectric sensing unit 3 .
  • the central membrane 37, the cantilever 32 and the auxiliary layer 36 can be integrally formed, so that the central membrane 37, the cantilever 32 and the auxiliary layer 36 can be formed in one process, thereby simplifying the process to a large extent.
  • the central membrane 37 may have openings 371 .
  • the specific number of openings 371 is not limited.
  • the central membrane 37 has an opening 371 .
  • the central membrane 37 may also have two or more openings 371 .
  • the shape of the above-mentioned opening is not limited, and may be a round hole or a square hole. The openings in this solution can release part of the sound pressure, thereby increasing the acoustic overload point (AOP) of the piezoelectric sensing unit.
  • AOP acoustic overload point
  • FIG. 10 is another schematic top view structural diagram of the piezoelectric sensing unit in the embodiment of the present application
  • FIG. 11 is a schematic cross-sectional structural schematic diagram of another lateral view of the piezoelectric sensing unit in the embodiment of the present application.
  • FIG. 11 is a cross-sectional view of B-B in FIG. 10 .
  • the above-mentioned central membrane 37 is located on the side of the cantilever 32 facing the base 31 , and the central membrane 37 is connected to the cantilever 32 through a connecting portion 38 .
  • the central membrane 37 and the cantilever 32 are located on different planes, the sensitivity of the piezoelectric sensing unit 3 is higher, and the performance of the piezoelectric microphone with the piezoelectric sensing unit 3 is also better.
  • the above-mentioned central membrane 37 and the cantilever 32 are arranged on different planes, at least part of the structure of the above-mentioned central membrane 37 can be overlapped with the cantilever 32, and the area of the central membrane 37 can be made larger to increase the effective input sound pressure. Improves the performance of piezoelectric microphones.
  • FIG. 12 is another schematic top view structural diagram of the piezoelectric sensing unit in the embodiment of the present application
  • FIG. 13 is a schematic lateral cross-sectional structural schematic diagram of the piezoelectric sensing unit in the embodiment of the present application. Please refer to Fig. 12 and Fig.
  • the above-mentioned connecting part 38 may also include a first connecting part 381 and a second connecting part 382, the above-mentioned first connecting part 381 and the cantilever 32 are integrally formed, and the second connecting part 382 is connected to the first The connection part 381 and the central membrane 37.
  • This solution is beneficial to improving the connection strength between the central membrane 37 and the cantilever 32 and improving the service life of the piezoelectric sensing unit 3 .
  • the first connecting portion 381 includes a plurality of first connecting holes 3811, and the second connecting portion 382 is connected to the first connecting holes 3811, which is conducive to improving the connection between the second connecting portion 382 and the first connecting portion 381. strength.
  • FIG. 14 is a schematic side view of the piezoelectric sensing unit in the embodiment of the present application. Please refer to FIG. 12 and FIG. It is connected with the second connection hole 325 .
  • This solution can improve the strength of the connection between the central membrane 37 and the cantilever 32 .
  • the central membrane 37 is connected with the cantilever 32 through the second connecting portion 382, which is beneficial to keep the central membrane 37 in an unfolded state.
  • FIG. 15 is a schematic diagram of a lateral cross-sectional structure of the piezoelectric sensing unit in the embodiment of the present application. Please refer to FIG. 15 .
  • the central membrane 37 can also have an additional mass 372 . This solution can make the central membrane 37 swing larger when subjected to sound pressure, so as to improve the sensitivity of the piezoelectric sensing unit 3 .
  • the lengths of the plurality of cantilevers 32 of the piezoelectric sensing unit 3 may be the same or different, which is not limited in this application.
  • the piezoelectric microphones can have different low-frequency resonance points, and the low-frequency sensitivity is high, thereby improving the recognition ability of the voiceprint.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Piezo-Electric Transducers For Audible Bands (AREA)
  • Details Of Audible-Bandwidth Transducers (AREA)

Abstract

本申请公开了一种压电感应单元、压电麦克风和终端。该压电感应单元包括基座、辅助层、中心膜、压电膜和多个悬臂。基座具有沿第一方向延伸的空腔，该空腔在基座的第一表面形成多边形开口，该多边形开口具有相邻的第一边和第二边。辅助层形成于基座的第一表面，该辅助层包括第一辅助部，上述第一辅助部位于第一表面与上述第一边相邻的区域。上述悬臂与多边形开口的边一一对应连接，悬臂包括第一端部和第二端部，上述第一端部与第一辅助部连接，且第一端部与第一辅助部的连接点位于第一辅助部靠近第二边的一侧。上述悬臂沿第二边的延伸方向延伸。中心膜与每个悬臂的第二端部连接。该方案中，悬臂的长度较长，有利于提升压电麦克风的信噪比。

Description

一种压电感应单元、压电麦克风和终端 技术领域
本申请涉及麦克风结构技术领域，特别涉及一种压电感应单元、压电麦克风和终端。
背景技术
麦克风是一种常见的声音捕捉设备，用于将声音信号转换为电信号。按种类来分，麦克风有动圈式、铝带式、驻极体式(electret microphone，ECM)、微机电系统(Micro-electromechanical systems，MEMS)电容式和MEMS压电式等。近代麦克风以驻极体式和MEMS电容式的较多；然而，驻极体麦克风由于工艺的原因，在生产的一致性、温度稳定性上远不如MEMS电容式麦克风。然而，MEMS电容式麦克风需要利用电荷泵来提升灵敏度，导致功耗较大。而MEMS压电式麦克风只要有声压，就可以利用压电材料的正压电效应转换为电荷输出，功耗较小。
现有技术中的压电麦克风包括具有空腔的基座，在上述基座具有空腔的区域制备悬臂，在悬臂上制备压电材料层，以形成压电麦克风的压电感应单元。现有技术中的压电麦克风中的悬臂，通常由空腔的边缘像中心伸展，或者由空腔的中心向空腔的边缘伸展，导致悬臂的长度较短。麦克风的电荷输出与悬臂受到的压力之间的关系，与悬臂的长度具有较强的相关性，因此，现有技术中压电麦克风的悬臂的长度较短，导致麦克风的电荷输出效果较差。
发明内容
本申请提供一种压电感应单元、压电麦克风和终端，以提升压电麦克风的信噪比，提升压电麦克风的性能。
第一方面，本申请提供了一种压电感应单元。该压电感应单元包括基座、辅助层、中心膜、压电膜和多个悬臂。上述基座具有沿第一方向延伸的空腔，该空腔在基座的第一表面形成多边形开口，该多边形开口具有相邻的第一边和第二边。上述辅助层形成于基座的第一表面，上述辅助层包括第一辅助部，上述第一辅助部位于第一表面与上述第一边相邻的区域。上述悬臂与多边形开口的边一一对应连接，具体的，上述悬臂包括第一端部和第二端部，上述第一端部与第一辅助部连接，且第一端部与第一辅助部的连接点位于第一辅助部靠近第二边的一侧。且上述悬臂沿第二边的延伸方向延伸，则该方案中，悬臂的长度较长，有利于提升压电麦克风的信噪比。上述中心膜与每个悬臂的第二端部连接，且多边形开口在第一平面的正投影完全覆盖中心膜在第一平面的正投影，上述第一平面垂直于第一方向。上述中心膜与基座的空腔相对，则声波进入到空腔之后，可以驱动中心膜振动，进而驱动悬臂摆动。压电膜设置于悬臂的表面，具体的，压电膜包括压电材料层、第一电极层和第二电极层，压电材料层连接第一电极层和第二电极层，则压电膜可以将悬臂的摆动转换成电信号。
上述悬臂包括第一边缘和第二边缘，且第一边缘和第二边缘连接在第一端部和第二端部之间。第一边缘和第二边缘中的至少一个与多边形的第二边平行。
具体制备上述压电感应单元时，可选的实现方式中，可以使中心膜与悬臂为一体成型 结构。该方案便于简化制备压电感应单元的工艺，此外，还可以提升中心膜与悬臂之间连接的可靠性。
上述中心膜可以设置有开孔。当然，该开孔的数量和形状都不做限制。上述中心膜的开孔可以释放部分声压，从而提升压电感应单元的声学过载点。
具体设置中心膜和悬臂时，可以使中心膜和悬臂位于同一平面，也可以使中心膜与悬臂位于不同的平面。当上述中心膜与悬臂位于不同的平面时，可以使中心膜位于悬臂朝向基座的一侧，中心膜通过连接部与悬臂连接。该方案中，压电感应单元的灵敏度较高，具有该压电感应单元的压电麦克风的性能也较好。
由于上述中心膜与悬臂设置于不同的平面，则可以使上述中心膜的至少部分结构与悬臂重叠，则可以使得中心膜的面积较大，以增大有效输入的声压，提升压电麦克风的性能。
上述连接部具体可以包括第一连接部和第二连接部，第一连接部可以与悬臂为一体成型结构，第二连接部连接第一连接部和中心膜。该方案可以提升中心膜与悬臂之间的连接强度，提升压电感应单元的使用寿命。
具体实现第一连接部与第二连接部之间的连接时，可以使第一连接部具有多个第一连接孔，第二连接部与上述第一连接孔连接。从而提升第一连接部与第二连接部之间的连接可靠性。
此外，上述第二连接部还可以与悬臂连接，从而使中心膜与悬臂实现连接。具体的，可以使悬臂包括至少一个第二连接孔，上述第二连接部与第二连接孔连接。该方案可以提升中心膜与悬臂连接的强度，还有利于使中心膜处于展开状态。
当悬臂的第一边缘与第二边缘不平行时，可以使悬臂沿垂直于第二边的方向的宽度为第一宽度。上述第一宽度从第一端部到第二端部逐渐减小。该方案中，悬臂与第一辅助部连接处的宽度较大，使得悬臂的第一端部附近的应力较大，有利于将声波产生的振动转化成电信号，提升信号转换效率。此外，第二端部的第一宽度较小，则中心膜的面积可以设计的较大，可以增大有效输入的声压，提升压电麦克风的性能。
上述悬臂的第一边缘和/或第二边缘垂直于与该悬臂连接的第一边。也就是说，第一边缘和第二边缘之中的至少一个，与第一边垂直，则该方案可以使悬臂垂直于第一边，以便于减少悬臂的根部的扭矩。
为了实现悬臂与第一边之间的垂直连接，可以使上述基座的内腔的第一边具有与悬臂对应的凹槽或者凸起。值得说明的是，上述第一边可以具有凹槽，从而有利于提升悬臂的长度。
上述压电膜的有效区域位于悬臂靠近与该悬臂连接的第一辅助部的一侧。由于悬臂与第一连接部连接的区域的应力较大，可以提升信号转换效率，提升压电麦克风的性能。
上述中心膜还可以具有附加质量块，该附加质量块可以使中心膜在受到声压时，中心膜的摆动幅度较大，以提升压电感应单元的灵敏度。
可选的技术方案中，上述压电感应单元的多个悬臂的长度可以相同，也可以不同，本申请不做限制。多个所述悬臂的长度不同。当多个悬臂的长度不同时，可以使压电麦克风具有不同的低频谐振点，低频灵敏度较高，从而可以提升声纹的识别能力。
可选的技术方案中，上述悬臂的材质不做限制，一种技术方案中，上述悬臂的材质可以与压电材料层不同，仅仅作为一个结构层，而只包括一层压电材料层。此时，压电感应单元为单压电层悬臂梁(Unimorph)模式的压电感应单元。另一种技术方案中，上述悬臂 的材质还可以与压电材料层相同，也就是说悬臂本身也作为压电材料层工作。此时，压电感应单元为双压电层悬臂梁(Bimorph)模式的压电感应单元。
具体制备上述压电麦克风时，可以使辅助层与悬臂为一体成型结构。一方面便于制备辅助层与悬臂，简化制备工艺。另一方面，有利于提升辅助层与悬臂之间连接的可靠性。
第二方面，本申请还提供了一种压电麦克风，该压电麦克风包括电路板、芯片和上述第一方面的压电感应单元。上述芯片设置于电路板，第一电极、第二电极和芯片连接，从而可以将压电感应单元将声波转换成的电信号进行处理。
可选的技术方案中，压电麦克风还包括外壳，电路板、芯片和压电感应单元设置于上述外壳内部。该外壳可以保护内部的电路板、芯片和压电感应单元，还可以屏蔽干扰。
第三方面，本申请还提供了一种终端，该终端包括上述第二方面的压电麦克风。该终端的收音效果较好。上述终端的具体类型不做限制，例如，上述终端可以为手机、耳机、智能设备、录音笔、助听器、话筒、声控设备或者车载语音交互设备等需要收录声音的终端。
附图说明
图1为本申请实施例中压电麦克风的一种结构示意图；
图2为本申请实施例中压电麦克风的另一种结构示意图；
图3为本申请实施例中压电感应单元的一种俯视结构示意；
图4为本申请实施例中压电感应单元的一种侧向剖视结构示意图；
图5为本申请实施例中压电感应单元的另一种俯视结构示意；
图6为本申请实施例中压电感应单元的另一种俯视结构示意；
图7为本申请实施例中压电感应单元的另一种俯视结构示意图；
图8为本申请实施例中压电感应单元的另一种侧向剖视结构示意图；
图9为本申请实施例中压电感应单元的另一种侧向剖视结构示意图；
图10为本申请实施例中压电感应单元的另一种俯视结构示意图；
图11为本申请实施例中压电感应单元的另一种侧向剖视结构示意图；
图12为本申请实施例中压电感应单元的另一种俯视结构示意图；
图13为本申请实施例中压电感应单元的另一种侧向剖视结构示意图；
图14为本申请实施例中压电感应单元的另一种侧向剖视结构示意图；
图15为本申请实施例中压电感应单元的另一种侧向剖视结构示意图。
附图标记：
1-电路板；                             2-芯片；
3-压电感应单元；                       31-基座；
311-空腔；                             312-第一表面；
313-多边形开口；                       3131-第一边；
3132-第二边；                          3133-凹槽；
32-悬臂；                              321-第一端部；
322-第二端部；                         323-第一边缘；
324-第二边缘；                         325-第二连接孔；
33-压电膜；                            331-压电材料层；
332-第一电极层；                       333-第二电极层；
334-有效工作区域；                     34-第一电极；
35-第二电极；                          36-辅助层；
361-第一辅助部；                       37-中心膜；
371-开孔；                             372-附加质量块；
38-连接部；                            381-第一连接部；
3811-第一连接孔；                      382-第二连接部；
4-外壳。
具体实施方式
为了方便理解，本申请实施例提供的压电感应单元、压电麦克风和终端。下面介绍一下其应用场景，麦克风作为常用的声音捕捉设备，目前被应用在各种终端中，以实现终端的通话或者声音控制等功能。麦克风的类型也在逐渐变化，MEMS压电式麦克风因其功耗较小，是本领域技术人员研究的重要方向。现有的压电麦克风的悬臂，通常由空腔的边缘像中心伸展，或者由空腔的中心向空腔的边缘伸展，导致悬臂的长度较短。麦克风的电荷输出与悬臂受到的压力之间的关系，与悬臂的长度具有较强的相关性，因此，现有技术中压电麦克风的悬臂的长度较短，导致麦克风的电荷输出效果较差。
下面将结合附图，对本申请实施例进行详细描述。以下实施例中所使用的术语只是为了描述特定实施例的目的，而并非旨在作为对本申请的限制。如在本申请的说明书和所附权利要求书中所使用的那样，单数表达形式“一个”、“一种”、“所述”、“上述”、“该”和“这一”旨在也包括例如“一个或多个”这种表达形式，除非其上下文中明确地有相反指示。
在本说明书中描述的参考“一个实施例”或“具体的实施例”等意味着在本申请的一个或多个实施例中包括结合该实施例描述的特定特征、结构或特点。术语“包括”、“包含”、“具有”及它们的变形都意味着“包括但不限于”，除非是以其他方式另外特别强调。
本申请提供了一种终端，该终端包括压电麦克风，利用压电麦克风来收录声音。上述终端的具体类型不做限制，例如，上述终端可以为手机、耳机、智能设备、录音笔、助听器、话筒、声控设备或者车载语音交互设备等需要收录声音的终端。
图1为本申请实施例中压电麦克风的一种结构示意图，如图1所示，本申请实施例中的压电麦克风包括电路板1、芯片2和压电感应单元3。上述芯片2设置于电路板1，具体的，芯片2可以与电路板1电连接。上述压电感应单元3包括基座31和形成与该基座31的悬臂32和压电膜(图中未示出)，上述基座31具有空腔311，悬臂32的第一端部321与基座31连接且悬设于空腔311，压电膜设置于上述悬臂32的表面。上述压电膜能够接收声波的振动，并转换成电信号。压电感应单元3的压电膜与芯片2电连接，从而能够通过芯片2处理压电感应单元3接收声波后产生的电信号。例如，芯片2对上述电信号进行采集、放大、滤波等处理，之后还可以输出模拟信号或者数字信号。该方案中，利用压电膜中的压电材料层的正压电特性，可以将声波转换成电信号，而无需配置其它的驱动器，有利于减小压电麦克风的体积，降低压电麦克风的功耗，有利于提升压电麦克风的使用时长，进而提升具有该压电麦克风的终端的使用时长。
请继续参考图1，上述压电麦克风还可以包括外壳4。上述电路板1、芯片2和压电感 应单元3设置于上述外壳4的内部，上述外壳4可以屏蔽干扰信号，且可以保护设置于上述壳体内部的器件。
压电麦克风的封装方式包括两种，一种是底部开口封装，另一种是顶部开口封装。如图1所示的实施例中的压电麦克风为底部开口封装的压电麦克风，底部开口封装的压电麦克风适合于薄型产品。该实施例中，压电感应单元3和芯片2分别安装于电路板1上，且电路板1与压电感应单元3的空腔311相对的区域具有开口，该开口对应为入声口。该封装方式中，无需在外壳4设置开口。
图2为本申请实施例中压电麦克风的另一种结构示意图，如图2所示的实施例中的压电麦克风为顶部开口封装的压电麦克风。该实施例中，压电感应单元3和芯片2分别安装于电路板1上，但是电路板1不具有开口，而外壳4具有开口，外壳4的开孔作为入声孔。
图3为本申请实施例中压电感应单元的一种俯视结构示意，图4为本申请实施例中压电感应单元的一种侧向剖视结构示意图。具体的，上述图4为图3中A-A处的剖视结构示意图。如图3和图4所示，该压电感应单元3包括基座31、辅助层36、多个悬臂32、中心膜37和压电膜33。其中，基座31为压电感应单元3的整体支撑件，该基座31形成有沿第一方向X延伸的空腔311，该空腔311可以形成声音传输的腔体。可以认为上述空腔311为管状结构，具有周侧密闭连接的侧壁，且形成有相对的第一开口和第二开口。上述第一开口朝向第二开口的方向就可以认为是上述第一方向X。上述空腔311在基座31的第一表面312形成多边形开口313，或者，也可以说基座31在第一表面312具有多边形开口313，该多边形开口313就是空腔311的开口。辅助层36形成于基座31的第一表面312，可以用于连接上述多个悬臂32。具体的，可以认为上述多边形开口313包括相邻的第一边3131和第二边3132，辅助层36包括第一辅助部361，该第一辅助部361位于基座31的第一表面312与第一边3131相邻的区域，也就是说第一边3131对应的基座31的第一表面312设置有该第一辅助部361。上述多个悬臂32与多边形开口313的边一一对应。悬臂32包括相对的第一端部321和第二端部322，其中，第一端部321与第一辅助部361靠近第二边3132的一侧连接，且悬臂32沿第二边3132的延伸方向延伸。上述中心膜37与每个悬臂32的第二端部322连接，则中心膜37在接收到声波时振动，可以带动悬臂32振动。具体的，多边形开口313在第一平面的正投影完全覆盖中心膜37在第一平面的正投影，上述第一平面垂直于上述第一方向X。使得中心膜37可以在基座31的空腔311中自由活动，以便于在声波的驱动下振动。上述压电膜33设置于悬臂32的表面，该压电膜33包括压电材料层331、第一电极层332和第二电极层333，该压电材料层331连接第一电极层332和第二电极层333。压电材料层331具有压电特性，当发生物理变形时，会产生电荷，且电荷的强度与变形的强度相关。因此，随着悬臂32的振动，压电材料层331会产生电荷，并可以通过第一电极层332和第二电极层333传输，将声音信号转化成电信号。
本申请实施例中，悬臂32的第一端部321连接至与第一边3131相邻的第一辅助部361，悬臂32与第一辅助部361的具体连接点靠近第二边3132的方向，且悬臂32沿第二边3132的延伸方向延伸，则悬臂32的长度最大可以达到接近第二边3132的长度的程度。该方案可以充分利用空腔311的开口的空间，使得悬臂32的长度较长。本申请实施例中的压电感应单元3可以为单压电层悬臂梁(Unimorph)模式的压电感应单元，也可以为双压电层悬臂梁(Bimorph)模式的压电感应单元。两种模式的悬臂梁信噪比(Signal to noise ratio，SNR)优化的相关项OPT(SNR∝10 Log(OPT))为：
Figure PCTCN2021142707-appb-000001
Figure PCTCN2021142707-appb-000002
其中ε为介电常数，tan(θ)是介电损耗，d 31为压电常数，w为悬臂32的宽度，L为悬臂32的长度，t为悬臂32的厚度，q uni是结构参数比值。可见，上述相关项OPT与悬臂32的长度成五次方的关系，也就是说，悬臂32的长度对于信噪比的影响非常大。本申请实施例在空腔311的尺寸一定的情况下，可以使得悬臂32的长度较大，从而压电麦克风的信噪比也更大。
可以理解的，多个悬臂32与多边形开口313的边一一对应，则多边形开口313的各个边在不同的基准下都可以理解为第一边3131，同样的，辅助层36的与多边形的各个边相邻的区域，也随着第一边3131的理解形成为第一辅助部361。也就是以哪个悬臂32为基准，则与该悬臂32连接辅助层36就是第一辅助部361，与该第一辅助部361相邻的多边形的边即为第一边3131。也就是说，当以不同的悬臂32为基准时，多边形开口313的每个边都可能形成为第一边3131，辅助层36与多边形开口313相对的部分都可以是第一辅助部361。
如图3所示，上述压电感应单元3还可以包括第一电极34和第二电极35，各个悬臂32的压电膜33的第一电极层332与第一电极34连接，各个悬臂32的压电膜33的第二电极层333与第二电极35连接。值得说明的是，各个第一电极层332之间可以串联也可以并联，各个第二电极层333之间可以串联也可以并联，本申请对此不做限制，可以根据压电麦克风的实际需求进行设计。
可选的技术方案中，本申请实施例中的压电感应单元3可以为单压电层悬臂梁(Unimorph)模式的压电感应单元，也可以为双压电层悬臂梁(Bimorph)模式的压电感应单元。上述压电感应单元3为Unimorph模式的压电感应单元时，上述悬臂32为基材，悬臂32的材质与压电材料层的材质不同，例如可以为含硅的材料制成的。其它实施例中，上述压电感应单元4为Bimorph模式的压电感应单元时，上述悬臂32的材质与压电材料层相同，也就是说，悬臂本身也作为压电材料层。当然，在一些实施例中，也可以使悬臂32为基材，而悬臂表面设置两层压电材料层，以形成Bimorph模式的压电感应单元。
请参考图3，上述悬臂32包括相对的第一边缘323和第二边缘324，该第一边缘323和第二边缘324分别连接在第一端部321与第二端部322之间。上述第一边缘323和第二边缘324中至少一个与多边形开口313的第二边3132平行。该实施例可以使得悬臂32的长度接近达到第二边3132的长度，也就是说，可以使悬臂32的长度较长，且较少的占用多边形开口313中间区域的面积，使得中心膜37的面积较大，有利于增大有效输入的声压。该方案可以充分利用多边形开口313的面积，以提升压电麦克风的性能。
具体的实现方式中，如图3所示，可以使上述第一边缘323和第二边缘324平行，则第一边缘323和第二边缘324均与第二边3132平行。或者，如图5和图6所示，示出了压电感应单元的另外两种俯视结构示意图，其它的实施例中，还可以使第一边缘323和第二边缘324不平行，可以仅使第一边缘323与第二边3132平行，而第二边缘324与第二边3132不平行。
请继续参考图5，当第一边缘323与第二边缘324不平行时，以悬臂32沿垂直于第二 边3132的方向的宽度为第一宽度d，则可以使上述第一宽度d从悬臂32的第一端部321到第二端部322逐渐增大。该方案中，悬臂32与第一辅助部361连接处的宽度较小，则可以为相邻的悬臂32预留较多的空间，有利于提升悬臂32的长度，进而提升OPT和SNR。
请继续参考图6，当第一边缘323与第二边缘324不平行时，以悬臂32沿垂直于第二边3132的方向的宽度为第一宽度d，则可以使上述第一宽度d从悬臂32的第一端部321到第二端部322逐渐减小。该方案中，悬臂32与第一辅助部361连接处的宽度较大，由于悬臂32的第一端部321附近的应力较大。因此，该实施例可以使悬臂32应力较大的区域的面积较大，有利于将声波产生的振动转化成电信号，提升信号转换效率。此外，第二端部322的第一宽度较小，则中心膜37的面积可以设计的较大，可以增大有效输入的声压，提升压电麦克风的性能。
请继续参考图4至图6，具体设置上述悬臂32时，可以使悬臂32的第一边缘323和第二边缘324中的至少一个垂直于与该悬臂32连接的第一边3131。该方案中，该实施例可以使得悬臂32与第一边3131垂直，则在悬臂32振动的过程中，第一端部321与第一辅助部361连接处不易出现扭矩，有利于形成有效的电荷输出。
图7为本申请实施例中压电感应单元的另一种俯视结构示意图。值得说明的是，为了便于表达特征，图7简化了附图的部分特征，仅仅展示了辅助层36和悬臂32两层结构。如图7所示，由于第一边3131和第二边3132不一定垂直，换句话说，多边形开口不一定为方形开口，还可能为三角形开口或者五边形开口等其它多边形开口，图7中示出的压电感应单元的多边形开口就是三角形开口。因此，为了使第一边缘323和第二边缘324中的至少一个垂直于与该悬臂32连接的第一边3131，可以使第一边3131具有与悬臂32对应的凸起或者凹槽3133。也就是说，悬臂32与对应上述凸起和凹槽3133位置的第一辅助部361连接，且保证第一边缘323和第二边缘324中的至少一个垂直于与该悬臂32连接的第一边3131。优选的实施例中，可以使第一边3131具有凹槽3133，从而有利于提升悬臂32的长度。
图8为本申请实施例中压电感应单元的另一种侧向剖视结构示意图。如图8所示，具体在悬臂32表面制备压电膜33时，可以使压电膜33的有效工作区域334位于悬臂32靠近与该悬臂32连接的第一辅助部361的一侧。也就是说，上述压电膜33的有效工作区334位于悬臂32的根部附近。由于，悬臂32靠近与该悬臂32连接的第一辅助部361的一侧的应力较大，因此，压电膜33的有效工作区域334位于此处，可以提升信号转换效率，提升压电麦克风的性能。
上述有效工作区域334指的是压电膜33可以将压电材料层331的变形转换成电信号的区域。具体可以为压电膜33同时具有第一电极层332、压电材料层331和第二电极层333的区域。
具体实现方式中，可以使压电膜33的整体均位于悬臂32靠近与该悬臂32连接的第一辅助部361的一侧，如图6和图8所示。或者，图9为本申请实施例中压电感应单元的另一种侧向剖视结构示意图。如图9所示，另一种实施例中，还可以仅使第一电极层332和第二电极层333中的至少一个设置于悬臂32靠近与该悬臂32连接的第一辅助部361的一侧，而压电材料层331覆盖整个悬臂32，该方案可以简化压电膜33的制作工艺。
当然，在其他实施例中，如图3所示的实施例中，也可以是压电膜33完全覆盖整个悬臂32，本申请对此不做限制。
上述第一电极层332和第二电极层333的具体制备方式不做限制，一种实施例中，如图8和图9所示，可以使第一电极层332和第二电极层333设置于压电材料层331的两侧表面，也就是上述第一电极层332、压电材料层331和第二电极层333依次叠置。另一种实施例中，上述第一电极层332与第二电极层333形成为叉指电极，具体的一种实施例中，第一电极层332和第二电极层333可以位于压电材料层331的同一侧表面。当然，在其他实施例中，也可以是上述第一电极层332、压电材料层331和第二电极层333依次叠置，指示第一电极层332为叉指结构，且第二电极层333为叉指结构，本申请对此不做限制。
请继续参考图5至图7，在具体制备上述辅助层36和悬臂32时，可以使辅助层36与悬臂32为一体结构。该方案一方面，便于制备上述辅助层36和悬臂32，可以采用一次工艺形成辅助层36和悬臂32，从而简化制备工艺。另一方面，可以使得悬臂32与辅助层36之间的连接较为可靠，从而提高压电感应单元3的结构可靠性。
此外，还可以使上述中心膜37与悬臂32为一体成型结构。同样，该方案一方面，便于制备上述中心膜37和悬臂32，可以采用一次工艺形成中心膜37和悬臂32，从而简化制备工艺。另一方面，可以使得悬臂32与中心膜37之间的连接较为可靠，从而提高压电感应单元3的结构可靠性。
具体的实施例中，可以使中心膜37、悬臂32和辅助层36为一体成型结构，从而可以一次工艺形成中心膜37、悬臂32和辅助层36，从而较大程度上简化工艺。
如图5和图6所示，上述中心膜37可以具有开孔371。具体的开孔371的数量不做限制。例如，可以如图5和图6所示，中心膜37具有一个开孔371。或者，如图3所示，中心膜37也可以具有两个或者多个开孔371。此外，上述开孔的形状也不做限制，可以为圆孔或者方孔等。该方案中的开孔可以释放部分声压，从而提升压电感应单元的声学过载点(AOP)。
如图5至图9所示的实施例中，中心膜37所在的平面与悬臂32所在的平面为同一平面。图10为本申请实施例中压电感应单元的另一种俯视结构示意图，图11为本申请实施例中压电感应单元的另一种侧向剖视结构示意图。具体的，图11为图10的B-B的截面剖视图。值得说明的是，为了便于表达特征，图10简化了附图的部分特征，仅仅展示了本实施例与其它实施例不同的技术特征。请参考图10和图11，一种实施例中，上述中心膜37位于悬臂32朝向基座31的一侧，且该中心膜37通过连接部38与悬臂32连接。该方案中，中心膜37与悬臂32位于不同的平面，压电感应单元3的灵敏度较高，具有该压电感应单元3的压电麦克风的性能也较好。
由于上述中心膜37与悬臂32设置于不同的平面，则可以使上述中心膜37的至少部分结构与悬臂32重叠，则可以使得中心膜37的面积较大，以增大有效输入的声压，提升压电麦克风的性能。
为了实现中心膜37与悬臂32的第二端部322连接，可以利用连接部38直接连接中心膜37与悬臂32的第二端部322，如图10所示。或者，图12为本申请实施例中压电感应单元的另一种俯视结构示意图，图13为本申请实施例中压电感应单元的一种侧向剖视结构示意图。请参考图12和图13，还可以使上述连接部38包括第一连接部381和第二连接部382，上述第一连接部381与悬臂32为一体成型结构，第二连接部382连接第一连接部381和中心膜37。该方案有利于提升中心膜37与悬臂32之间的连接强度，提升压电感应单元3的使用寿命。
具体的，上述第一连接部381包括多个第一连接孔3811，第二连接部382与上述第一连接孔3811连接，有利于提升第二连接部382与第一连接部381之间的连接强度。
图14为本申请实施例中压电感应单元的一种侧向剖视结构示意图，请参考图12和图14，上述悬臂32还可以包括至少一个第二连接孔325，第二连接部38还与第二连接孔325连接。该方案可以提升中心膜37与悬臂32连接的强度。特别是中心膜37的面积较大，中心膜37的部分结构与悬臂32重叠时，中心膜37通过第二连接部382与悬臂32连接，有利于使中心膜37处于展开状态。
图15为本申请实施例中压电感应单元的一种侧向剖视结构示意图，请参考图15，在具体设置上述中心膜37时，还可以使中心膜37具有附加质量块372。该方案可以使中心膜37在受到声压时，中心膜37的摆动幅度较大，以提升压电感应单元3的灵敏度。
在具体实施例中，压电感应单元3的多个悬臂32的长度可以相同，也可以不同，本申请不做限制。当多个悬臂32的长度不同时，可以使压电麦克风具有不同的低频谐振点，低频灵敏度较高，从而可以提升声纹的识别能力。
显然，本领域的技术人员可以对本申请进行各种改动和变型而不脱离本申请的保护范围。这样，倘若本申请的这些修改和变型属于本申请权利要求及其等同技术的范围之内，则本申请也意图包含这些改动和变型在内。

Claims (20)

  1. 一种压电感应单元，其特征在于，包括：
    基座，形成有沿第一方向延伸的空腔，所述空腔在所述基座的第一表面形成多边形开口，所述多边形开口包括相邻的第一边和第二边；
    辅助层，形成于所述基座的所述第一表面，所述辅助层包括第一辅助部，所述第一辅助部位于所述第一表面与所述第一边相邻的区域；
    多个悬臂，与所述多边形开口的边一一对应；所述悬臂包括相对的第一端部和第二端部，所述第一端部与所述第一辅助部靠近所述第二边的一侧连接；所述悬臂沿所述第二边的延伸方向延伸；
    中心膜，所述中心膜与每个所述悬臂的所述第二端部连接，所述多边形开口在第一平面的正投影完全覆盖所述中心膜在所述第一平面的正投影，所述第一平面垂直于所述第一方向；
    压电膜，设置于所述悬臂的表面；所述压电膜包括压电材料层、第一电极层和第二电极层，所述压电材料层连接所述第一电极层和所述第二电极层。
  2. 如权利要求1所述的压电感应单元，其特征在于，所述悬臂包括相对的第一边缘和第二边缘，所述第一边缘和/或所述第二边缘与所述多边形开口的所述第二边平行。
  3. 如权利要求1或2任一项所述的压电感应单元，其特征在于，所述中心膜与所述悬臂为一体成型结构。
  4. 如权利要求3所述的压电感应单元，其特征在于，所述中心膜具有开孔。
  5. 如权利要求1或2所述的压电感应单元，其特征在于，所述中心膜位于所述悬臂朝向所述基座的一侧，所述中心膜通过连接部与所述悬臂连接。
  6. 如权利要求5所述的压电感应单元，其特征在于，所述中心膜至少部分结构与所述悬臂重叠。
  7. 如权利要求5或6所述的压电感应单元，其特征在于，所述连接部包括第一连接部和第二连接部，所述第一连接部与所述悬臂为一体成型结构，所述第二连接部连接所述第一连接部和所述中心膜。
  8. 如权利要求7所述的压电感应单元，其特征在于，所述第一连接部包括多个第一连接孔，所述第二连接部与所述第一连接孔连接。
  9. 如权利要求8所述的压电感应单元，其特征在于，所述悬臂包括至少一个第二连接孔，所述第二连接部与所述第二连接孔连接。
  10. 如权利要求1～9任一项所述的压电感应单元，其特征在于，所述悬臂沿垂直于所述第二边的方向的宽度为第一宽度，所述第一宽度从所述第一端部到所述第二端部逐渐增加或减小。
  11. 如权利要求1～10任一项所述的压电感应单元，其特征在于，所述悬臂的所述第一边缘和/或所述第二边缘垂直于与所述悬臂连接的所述第一边。
  12. 如权利要求11所述的压电感应单元，其特征在于，所述内腔的所述第一边具有与所述悬臂对应的凹槽或者凸起。
  13. 如权利要求1～12任一项所述的压电感应单元，其特征在于，所述压电膜的有效工作区域位于悬臂靠近与该悬臂连接的第一辅助部的一侧。
  14. 如权利要求1～13任一项所述的压电感应单元，其特征在于，所述中心膜具有附加质量块。
  15. 如权利要求1～14任一项所述的压电感应单元，其特征在于，多个所述悬臂的长度不同。
  16. 如权利要求1～15任一项所述的压电感应单元，其特征在于，所述悬臂的材质与所述压电材料层的材质相同。
  17. 如权利要求1～16任一项所述的压电感应单元，其特征在于，所述辅助层与所述悬臂为一体成型结构。
  18. 一种压电麦克风，其特征在于，包括电路板、芯片和如权利要求1～17任一项所述的压电感应单元，其中，所述芯片设置于所述电路板，所述第一电极和第二电极与所述芯片连接。
  19. 如权利要求18所述的压电麦克风，其特征在于，还包括外壳，所述电路板、芯片和压电感应单元设置于所述外壳内部。
  20. 一种终端，其特征在于，包括如权利要求18或19所述的压电麦克风。
PCT/CN2021/142707 2021-12-29 2021-12-29 一种压电感应单元、压电麦克风和终端 WO2023123129A1 (zh)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/CN2021/142707 WO2023123129A1 (zh) 2021-12-29 2021-12-29 一种压电感应单元、压电麦克风和终端

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2021/142707 WO2023123129A1 (zh) 2021-12-29 2021-12-29 一种压电感应单元、压电麦克风和终端

Publications (1)

Publication Number Publication Date
WO2023123129A1 true WO2023123129A1 (zh) 2023-07-06

Family

ID=86996951

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2021/142707 WO2023123129A1 (zh) 2021-12-29 2021-12-29 一种压电感应单元、压电麦克风和终端

Country Status (1)

Country Link
WO (1) WO2023123129A1 (zh)

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018011048A1 (de) * 2016-07-13 2018-01-18 Robert Bosch Gmbh Detektionseinrichtung für piezoelektrisches mikrofon
US20180159021A1 (en) * 2015-04-24 2018-06-07 Vesper Technologies Inc. Mems process power
CN111050256A (zh) * 2019-12-17 2020-04-21 武汉大学 一种小型化的高灵敏度压电式麦克风
CN212572963U (zh) * 2020-07-06 2021-02-19 瑞声新能源发展(常州)有限公司科教城分公司 一种压电式mems麦克风
CN112492472A (zh) * 2020-11-25 2021-03-12 瑞声新能源发展(常州)有限公司科教城分公司 压电式麦克风及压电式麦克风装置
US20210193899A1 (en) * 2019-12-20 2021-06-24 Vanguard International Semiconductor Singapore Pte. Ltd. Microphone device and method of forming a microphone device
CN113507676A (zh) * 2021-08-13 2021-10-15 中北大学 硅基悬臂梁式mems压电麦克风的结构及装置
CN113526456A (zh) * 2021-06-30 2021-10-22 青岛芯笙微纳电子科技有限公司 一种mems压电芯片及mems器件

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20180159021A1 (en) * 2015-04-24 2018-06-07 Vesper Technologies Inc. Mems process power
WO2018011048A1 (de) * 2016-07-13 2018-01-18 Robert Bosch Gmbh Detektionseinrichtung für piezoelektrisches mikrofon
CN111050256A (zh) * 2019-12-17 2020-04-21 武汉大学 一种小型化的高灵敏度压电式麦克风
US20210193899A1 (en) * 2019-12-20 2021-06-24 Vanguard International Semiconductor Singapore Pte. Ltd. Microphone device and method of forming a microphone device
CN212572963U (zh) * 2020-07-06 2021-02-19 瑞声新能源发展(常州)有限公司科教城分公司 一种压电式mems麦克风
CN112492472A (zh) * 2020-11-25 2021-03-12 瑞声新能源发展(常州)有限公司科教城分公司 压电式麦克风及压电式麦克风装置
CN113526456A (zh) * 2021-06-30 2021-10-22 青岛芯笙微纳电子科技有限公司 一种mems压电芯片及mems器件
CN113507676A (zh) * 2021-08-13 2021-10-15 中北大学 硅基悬臂梁式mems压电麦克风的结构及装置

Similar Documents

Publication Publication Date Title
US10484798B2 (en) Acoustic transducer and microphone using the acoustic transducer
CN110052391B (zh) 双谐振模式耦合的微机械压电超声波换能器
CN109413554B (zh) 一种指向性mems麦克风
CN101854578B (zh) 一种基于硅硅键合工艺的微型麦克风制备方法
CN102918874B (zh) 音响转换器、及利用该音响转换器的传声器
CN111148000B (zh) 一种mems麦克风及阵列结构
CN110267184A (zh) Mems麦克风
US11905164B2 (en) Micro-electro-mechanical system acoustic sensor, micro-electro-mechanical system package structure and method for manufacturing the same
CN105492373A (zh) 具有高深厚比褶皱振膜的硅麦克风和有该硅麦克风的封装
CN217985406U (zh) 一种mems压电扬声器
US20230217163A1 (en) Bone conduction sound transmission devices
CN211792035U (zh) 一种mems芯片及包括其的mems麦克风
CN209072736U (zh) 一种指向性mems麦克风
KR101496192B1 (ko) 피에조 진동판이 구비된 멤스 마이크로폰
JP4811035B2 (ja) 音響センサ
WO2023123129A1 (zh) 一种压电感应单元、压电麦克风和终端
CN114222231B (zh) 基于固支梁结构的双晶压电式mems麦克风
CN208258074U (zh) 电容式mems麦克风
CN110868680A (zh) 一种改进基材的麦克风结构
CN113596690B (zh) 新型压电式mems麦克风的结构及装置
US20230011561A1 (en) Piezoelectric microphone with enhanced anchor
CN216649989U (zh) 梳状电容式麦克风
CN216649988U (zh) 一种mems麦克风
CN213094485U (zh) Mems麦克风
CN201699978U (zh) 一种电容式微型硅麦克风

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: 21969497

Country of ref document: EP

Kind code of ref document: A1