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CN215918086U - Piezoelectric ultrasonic transducer - Google Patents

Piezoelectric ultrasonic transducer Download PDF

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Publication number
CN215918086U
CN215918086U CN202021362563.2U CN202021362563U CN215918086U CN 215918086 U CN215918086 U CN 215918086U CN 202021362563 U CN202021362563 U CN 202021362563U CN 215918086 U CN215918086 U CN 215918086U
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CN
China
Prior art keywords
piezoelectric
electrode
structural layer
piezoelectric unit
ultrasonic transducer
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.)
Expired - Fee Related
Application number
CN202021362563.2U
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Chinese (zh)
Inventor
石正雨
童贝
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 Nanjing Co Ltd
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AAC Technologies Holdings Nanjing Co Ltd
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Priority to CN202021362563.2U priority Critical patent/CN215918086U/en
Priority to PCT/CN2020/105088 priority patent/WO2022007043A1/en
Application granted granted Critical
Publication of CN215918086U publication Critical patent/CN215918086U/en
Expired - Fee Related legal-status Critical Current
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    • HELECTRICITY
    • H10SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10NELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00Piezoelectric or electrostrictive devices
    • H10N30/01Manufacture or treatment
    • H10N30/05Manufacture of multilayered piezoelectric or electrostrictive devices, or parts thereof, e.g. by stacking piezoelectric bodies and electrodes

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Transducers For Ultrasonic Waves (AREA)

Abstract

The utility model provides a piezoelectric ultrasonic transducer, which comprises a substrate and a vibrating diaphragm, wherein a cavity is arranged in the center of the substrate, the vibrating diaphragm comprises a structural layer, a first piezoelectric unit and a second piezoelectric unit, the structural layer is fixedly connected with the substrate and covers the cavity, the first piezoelectric unit is connected with the upper surface of the structural layer, which is far away from the cavity, and the second piezoelectric unit is connected with the lower surface of the structural layer, which is far towards the cavity; the first piezoelectric unit comprises a first electrode close to the structural layer, a second electrode far away from the structural layer and a first piezoelectric layer clamped between the first electrode and the second electrode; the second piezoelectric unit comprises a third electrode close to the structural layer, a fourth electrode far away from the structural layer and a second piezoelectric layer clamped between the third electrode and the fourth electrode. The utility model can reduce the thickness of the structural layer, improve the electromechanical conversion efficiency and simultaneously improve the sound pressure.

Description

Piezoelectric ultrasonic transducer
[ technical field ] A method for producing a semiconductor device
The utility model relates to the field of ultrasonic sensors, in particular to a piezoelectric ultrasonic transducer.
[ background of the utility model ]
The piezoelectric ultrasonic transducer is a device for converting electric energy and mechanical energy into each other, and utilizes the piezoelectric property of a piezoelectric diaphragm to generate vibration motion so as to generate sound.
Referring to fig. 1, a piezoelectric ultrasonic transducer in the prior art includes a substrate 110 having a cavity 111 at a center thereof, and a diaphragm 120 fixed on the substrate 110 and covering the cavity 111, where the diaphragm 120 includes a structural layer 121 connected to the substrate 110, and a piezoelectric unit 122 attached above the structural layer 121, the piezoelectric unit 122 includes a first electrode 1221 close to the structural layer, a second electrode 1222 far away from the structural layer 121, and a piezoelectric layer 1223 sandwiched between the first electrode 1221 and the second electrode 1222, and after the first electrode 1221 and the second electrode 1222 are connected to a power supply, the piezoelectric layer 1223 is excited by an alternating current electric field/magnetic field to generate a transverse expansion deformation, so as to drive the structural layer 121 to generate a deformation, and convert electrical energy into mechanical energy.
Since the piezoelectric unit 122 is only located on one side of the structural layer 121, in order to ensure that the neutral surface of the whole diaphragm 120 is not located on the piezoelectric layer 1223, the thickness of the structural layer 121 is increased in the prior art, generally, the thickness of the structural layer 121 is greater than that of the piezoelectric unit 122, however, the structural layer 121 is increased in thickness, which causes more mechanical energy to be stored in the structural layer 121, and also reduces the electromechanical conversion efficiency of the piezoelectric ultrasonic transducer.
[ summary of the utility model ]
The utility model aims to provide a piezoelectric ultrasonic transducer with higher electromechanical conversion efficiency.
The technical scheme of the utility model is as follows:
a piezoelectric ultrasonic transducer comprises a substrate and a vibrating diaphragm, wherein a cavity is arranged in the center of the substrate, the vibrating diaphragm comprises a structural layer, a first piezoelectric unit and a second piezoelectric unit, the structural layer is fixedly connected with the substrate and covers the cavity, the first piezoelectric unit is connected with the upper surface of the structural layer, which is far away from the cavity, and the second piezoelectric unit is connected with the lower surface of the structural layer, which is far towards the cavity; the first piezoelectric unit comprises a first electrode close to the structural layer, a second electrode far away from the structural layer and a first piezoelectric layer clamped between the first electrode and the second electrode; the piezoelectric unit comprises a third electrode close to the structural layer, a fourth electrode far away from the structural layer and a second piezoelectric layer clamped between the third electrode and the fourth electrode.
The utility model has the beneficial effects that:
the second piezoelectric unit is additionally arranged on the lower surface of the structural layer, so that the neutral surface of the whole vibrating diaphragm is far away from the first piezoelectric unit, the thickness of the structural layer can be reduced, the mechanical energy stored in the structural layer is reduced, and the electromechanical conversion efficiency of the piezoelectric ultrasonic transducer is improved. On the other hand, the first piezoelectric unit and the second piezoelectric unit can simultaneously provide transverse stretching deformation, and sound pressure is improved.
[ description of the drawings ]
Fig. 1 is a schematic cross-sectional structure diagram of a piezoelectric ultrasonic transducer in the prior art.
Fig. 2 is a schematic cross-sectional structure diagram of a piezoelectric ultrasonic transducer according to an embodiment of the present invention.
[ detailed description ] embodiments
The utility model is further described with reference to the following figures and embodiments.
Referring to fig. 2, the present invention discloses a piezoelectric ultrasonic transducer, including a substrate 210 and a diaphragm 220, a cavity 211 is disposed in the center of the substrate 210, the diaphragm 220 includes a structural layer 221, a first piezoelectric unit 224 and a second piezoelectric unit 223, the structural layer 221 is fixedly connected to the substrate 210 and covers the cavity 211, the first piezoelectric unit 224 is connected to an upper surface 1211 of the structural layer 221 facing away from the cavity 211, and the second piezoelectric unit 223 is connected to a lower surface 1212 of the structural layer 221 facing the cavity 211; the first piezoelectric unit 224 includes a first electrode 2241 close to the structural layer 221, a second electrode 2242 far from the structural layer 221, and a first piezoelectric layer 2243 interposed between the first electrode 2241 and the second electrode 2242; the second piezoelectric unit 223 includes a third electrode 2231 near the structural layer 221, a fourth electrode 2232 far from the structural layer 221, and a second piezoelectric layer 2233 interposed between the third electrode 2231 and the fourth electrode 2232. The addition of the second piezoelectric unit 223 makes the neutral surface of the whole diaphragm 220 away from the first piezoelectric unit 224, so that the thickness of the structural layer 221 can be reduced, the mechanical energy stored in the structural layer 221 can be reduced, and the electromechanical conversion efficiency of the piezoelectric ultrasonic transducer can be improved.
Preferably, the first electrode 2241 and the fourth electrode 2232 have the same potential and are set to a first potential, the second electrode 2242 and the third electrode 2231 have the same potential and are set to a second potential, and when the liquid crystal display device is used, one of the first potential and the second potential is grounded, and the other of the first potential and the second potential serves as an output terminal for receiving a signal. When the first piezoelectric unit 224 provides tensile deformation, the first piezoelectric unit 224 drives the structural layer 221 to arch in the direction of the first piezoelectric unit 224, the second piezoelectric unit 223 provides contraction deformation, the second piezoelectric unit 223 drives the structural layer 221 to continue to arch in the direction of the first piezoelectric unit 224, and the first piezoelectric unit 224 and the second piezoelectric unit 223 can simultaneously provide lateral expansion deformation of the structural layer 221, so that the deformation amplitude of the structural layer 221 is increased, and the sound pressure is increased.
The so-called neutral plane, i.e. an imaginary plane in which the lateral dimension does not change during deformation of the diaphragm 220, the tendency of the diaphragm 220 on both sides of the neutral plane to deform laterally is reversed. If the neutral plane is located in the first piezoelectric layer 2243 or the second piezoelectric layer 2233, the piezoelectric layer includes two deformations with opposite directions, so that the efficiency of converting electrical energy into mechanical energy is reduced, resulting in a decrease in the electromechanical coupling coefficient of the piezoelectric ultrasonic transducer. According to the utility model, the first piezoelectric unit 224 and the second piezoelectric unit 223 are respectively arranged on the two sides of the structural layer 221, so that the electromechanical coupling coefficient reduction caused by the opposite deformation of the piezoelectric layers is avoided, and meanwhile, the thickness of the structural layer 221 can be greatly reduced.
Preferably, neither the first piezoelectric unit 224 nor the second piezoelectric unit 223 is in contact with the substrate 210, so that the residual stress of the first piezoelectric unit 224 and the second piezoelectric unit 223 can be better released.
Preferably, the first piezoelectric unit 224 and the second piezoelectric unit 223 are both disposed at the center of the structural layer 221.
The shape of the first piezoelectric element 224 may be circular, square, circular, or the like; the second piezoelectric unit 223 may have a circular, square, or circular shape. The first piezoelectric element 224 and the second piezoelectric element 223 may have the same shape or different shapes, and when the first piezoelectric element 224 is a circular ring, the second piezoelectric element 223 may have a circular ring shape or may have a circular shape or a square shape embedded in a circular ring shape.
Preferably, the shape, size, structure and material of the first piezoelectric unit 224 and the second piezoelectric unit 223 are the same, so that the neutral surface of the whole diaphragm 220 is always located in the structural layer 221, and the thickness of the structural layer 221 can be arbitrarily set as required.
Preferably, the structural layer 221 is a uniform thickness plate, which is convenient for manufacturing.
The material of the substrate 210 may be silicon, sapphire, ceramic, glass, polymer, or the like, and preferably, in the present embodiment, the material of the substrate 210 is silicon.
The material of the structural layer 221 may be silicon dioxide, polysilicon, silicon nitride, or a polymer, and preferably, in this embodiment, the material of the structural layer 221 is silicon dioxide.
The material of the first piezoelectric layer 2243 can be aluminum nitride, zinc oxide, lead zirconate titanate, or the like; the material of the second piezoelectric layer 2233 may be aluminum nitride, zinc oxide, lead zirconate titanate, or the like. The material of the first piezoelectric layer 2243 and the material of the second piezoelectric layer 2233 may be the same or different. In this embodiment, the first piezoelectric layer 2243 and the second piezoelectric layer 2233 are made of the same material and are both lead zirconate titanate piezoelectric ceramics.
The material of each of the first electrode 2241, the second electrode 2242, the third electrode 2231, and the fourth electrode 2232 may be any one selected from molybdenum, platinum, and aluminum, and the material of each of the first electrode 2241, the second electrode 2242, the third electrode 2231, and the fourth electrode 2232 may be different from or the same as each other.
The above are only embodiments of the present invention, and it should be noted that, for those skilled in the art, modifications can be made without departing from the inventive concept of the present invention, but these are all within the scope of the present invention.

Claims (7)

1. A piezoelectric ultrasonic transducer is characterized by comprising a substrate and a vibrating diaphragm,
the vibrating diaphragm comprises a structural layer, a first piezoelectric unit and a second piezoelectric unit, the structural layer is fixedly connected with the substrate and covers the cavity, the first piezoelectric unit is connected with the upper surface of the structural layer, which is far away from the cavity, and the second piezoelectric unit is connected with the lower surface of the structural layer, which is far towards the cavity;
the first piezoelectric unit comprises a first electrode close to the structural layer, a second electrode far away from the structural layer and a first piezoelectric layer clamped between the first electrode and the second electrode;
the second piezoelectric unit comprises a third electrode close to the structural layer, a fourth electrode far away from the structural layer and a second piezoelectric layer clamped between the third electrode and the fourth electrode.
2. The piezoelectric ultrasonic transducer according to claim 1, wherein the first electrode and the fourth electrode are at the same potential, and the second electrode and the third electrode are at the same potential.
3. The piezoelectric ultrasonic transducer of claim 2, wherein neither the first piezoelectric element nor the second piezoelectric element is in contact with the substrate.
4. The piezoelectric ultrasonic transducer of claim 3, wherein the first piezoelectric element and the second piezoelectric element are both disposed in the center of the structural layer.
5. The piezoelectric ultrasonic transducer according to claim 4, wherein the first piezoelectric unit has a circular, square or circular shape; the second piezoelectric unit is circular, square or circular.
6. The piezoelectric ultrasonic transducer according to claim 5, wherein the first piezoelectric element and the second piezoelectric element are identical in shape, size, structure, and material.
7. The piezoelectric ultrasonic transducer of claim 6, wherein the structural layer is an equal thickness plate.
CN202021362563.2U 2020-07-10 2020-07-10 Piezoelectric ultrasonic transducer Expired - Fee Related CN215918086U (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN202021362563.2U CN215918086U (en) 2020-07-10 2020-07-10 Piezoelectric ultrasonic transducer
PCT/CN2020/105088 WO2022007043A1 (en) 2020-07-10 2020-07-28 Piezoelectric ultrasonic transducer

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202021362563.2U CN215918086U (en) 2020-07-10 2020-07-10 Piezoelectric ultrasonic transducer

Publications (1)

Publication Number Publication Date
CN215918086U true CN215918086U (en) 2022-03-01

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WO (1) WO2022007043A1 (en)

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0947048A (en) * 1995-08-01 1997-02-14 Toyota Central Res & Dev Lab Inc Transducer for ultrasonic actuator
WO2010131540A1 (en) * 2009-05-11 2010-11-18 日本電気株式会社 Piezoelectric actuator and audio components
CN102255042A (en) * 2011-07-08 2011-11-23 南京邮电大学 Double-piezoelectric ceramic substrate energy harvester and preparation method thereof
JP5836755B2 (en) * 2011-10-04 2015-12-24 富士フイルム株式会社 Piezoelectric element and liquid discharge head
CN110350079A (en) * 2019-07-15 2019-10-18 京东方科技集团股份有限公司 A kind of piezoelectric element and preparation method thereof and ultrasonic sensor
CN111146327A (en) * 2019-12-25 2020-05-12 诺思(天津)微系统有限责任公司 Single crystal piezoelectric structure, method for manufacturing same, and electronic device having single crystal piezoelectric laminated structure

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