CN117395581A - Piezoelectric electret electroacoustic device - Google Patents
Piezoelectric electret electroacoustic device Download PDFInfo
- Publication number
- CN117395581A CN117395581A CN202311175544.7A CN202311175544A CN117395581A CN 117395581 A CN117395581 A CN 117395581A CN 202311175544 A CN202311175544 A CN 202311175544A CN 117395581 A CN117395581 A CN 117395581A
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- Prior art keywords
- piezoelectric electret
- piezoelectric
- electroacoustic device
- film
- flexible
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- 239000000463 material Substances 0.000 claims abstract description 28
- 239000004743 Polypropylene Substances 0.000 claims description 6
- 239000000853 adhesive Substances 0.000 claims description 6
- 230000001070 adhesive effect Effects 0.000 claims description 6
- 229920001155 polypropylene Polymers 0.000 claims description 6
- -1 polypropylene Polymers 0.000 claims description 4
- 230000000694 effects Effects 0.000 abstract description 19
- 230000035945 sensitivity Effects 0.000 abstract description 6
- 238000004519 manufacturing process Methods 0.000 abstract description 4
- 229920000642 polymer Polymers 0.000 description 9
- 238000006243 chemical reaction Methods 0.000 description 7
- 238000000034 method Methods 0.000 description 5
- 238000013459 approach Methods 0.000 description 3
- 229920001577 copolymer Polymers 0.000 description 3
- 238000013461 design Methods 0.000 description 3
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 3
- 239000004810 polytetrafluoroethylene Substances 0.000 description 3
- 239000002033 PVDF binder Substances 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000005284 excitation Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
- 239000004812 Fluorinated ethylene propylene Substances 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 238000004377 microelectronic Methods 0.000 description 1
- 229920009441 perflouroethylene propylene Polymers 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 229920006254 polymer film Polymers 0.000 description 1
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
Abstract
The application provides a piezoelectric electret electroacoustic device manufactured by utilizing the inverse piezoelectric effect of a piezoelectric electret material. The piezoelectric electret electroacoustic device comprises a vibrating unit formed by a flexible lower electrode, a plurality of layers of piezoelectric electret films and a flexible upper electrode, wherein the flexible lower electrode and the plurality of layers of piezoelectric electret films are arranged in a stacked mode, the plurality of layers of piezoelectric electret films are adhered between the flexible lower electrode and the flexible upper electrode, and the plurality of layers of piezoelectric electret films are connected in series. Compared with the traditional capacitive/moving coil structure, the piezoelectric electret electroacoustic device reduces the volume and the number of parts, ensures the reliability and is convenient for the requirement of mass production; moreover, the piezoelectric electret electroacoustic device can achieve a very high piezoelectric coefficient and achieve higher sensitivity.
Description
Technical Field
The application relates to the technical field of electroacoustic devices, in particular to a piezoelectric electret electroacoustic device manufactured by utilizing the inverse piezoelectric effect of a piezoelectric electret material.
Background
The traditional loudspeaker is mostly of a capacitive/moving coil type structure, the capacitive/moving coil type structure is complex, and parts with extremely high precision requirements are needed to be matched.
Disclosure of Invention
The technical problem that this application mainly solves is to provide a piezoelectret electroacoustic device that utilizes piezoelectret material's contrary piezoelectricity effect preparation.
The utility model provides a piezoelectret electroacoustic device, include by the flexible bottom electrode and the multilayer piezoelectret film and the flexible vibration unit that constitutes of going up the electrode of range upon range of setting, the multilayer piezoelectret film bond in flexible bottom electrode with between the flexible top electrode, the multilayer piezoelectret film concatenates.
In some alternative embodiments, the piezoelectric electret electroacoustic device further comprises: and the annular connecting piece is connected to the periphery of the vibration unit.
In some alternative embodiments, the annular connector is a stickable adhesive material.
In some alternative embodiments, the piezoelectric electret electroacoustic device further comprises: an insulating ring separating the multilayer piezoelectric electret film and the ring member.
In some alternative embodiments, the lower end face and the upper end face of the insulating ring are bonded to the flexible lower electrode and the flexible upper electrode, respectively.
In some alternative embodiments, the upper surface of the flexible upper electrode and the upper end surface of the annular connector are coplanar, and the lower surface of the flexible lower electrode and the lower end surface of the annular connector are coplanar.
In some alternative embodiments, the piezoelectric electret film is a porous polymeric piezoelectric electret film.
In some alternative embodiments, the porous polymeric piezoelectric electret film is a polypropylene film.
In some alternative embodiments, the porous polymeric piezoelectric electret film comprises internally honeycomb-shaped lenticular pores.
In some alternative embodiments, the porous polymeric piezoelectric electret film has a thickness of between 30 microns and 80 microns.
From the above technical scheme, the technical effects achieved by the piezoelectric electret electroacoustic device of the application include:
(1) compared with the traditional capacitive/moving coil structure, the piezoelectric electret electroacoustic device can greatly reduce the volume of the electroacoustic device, meanwhile, the number of parts is greatly reduced, the reliability is also ensured, and the requirement of mass production is facilitated.
(2) The porous polymer piezoelectric electret film (such as PP material) can reach very high piezoelectric coefficient, which is 1 order of magnitude higher than the piezoelectric activity of PVDF (polyvinylidene fluoride) ferroelectric polymer and copolymer thereof; secondly, the thickness of the porous polymer piezoelectric electret film can be small, the minimum thickness can be 30 microns, and the requirements on geometric dimensions are easily met; in addition, the porous polymer piezoelectric electret film has wide raw material sources, and the material cost and the processing preparation are much easier than those of piezoelectric ceramics and ferroelectric single crystal materials.
(3) The multilayer piezoelectric electret films are connected in series to drive to perform electroacoustic conversion, so that the piezoelectric effect can be improved, and higher sensitivity can be realized.
(4) Furthermore, the piezoelectric electret electroacoustic device can be adhered to a certain surface of a preset device (object) by using an adhesive material of the piezoelectric electret electroacoustic device, and can drive the surface to vibrate and sound, so that the piezoelectric electret electroacoustic device has wide application scenes.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following description will briefly introduce the drawings needed in the embodiments and the description of the prior art, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic cross-sectional structure of a piezoelectric electret electroacoustic device proposed in the present application.
Detailed Description
In order to make the present application solution better understood by those skilled in the art, the following description will be made in detail and with reference to the accompanying drawings in the embodiments of the present application, it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments herein without making any inventive effort, shall fall within the scope of the present application.
The terms first, second, third and the like in the description and in the claims of the application and in the above-described figures, are used for distinguishing between different objects and not necessarily for describing a particular sequential or chronological order. Furthermore, the terms "comprise" and "have," as well as any variations thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those listed steps or elements but may include other steps or elements not listed or inherent to such process, method, article, or apparatus.
The following will each explain in detail by means of specific examples.
Referring to fig. 1, fig. 1 shows a piezoelectric electret electroacoustic device proposed in the present application.
The piezoelectric electret electroacoustic device is driven by adopting a piezoelectric electret in a film form. A piezoelectric electret is an electret having a piezoelectric effect. The polymer film containing the closed pore structure shows outstanding piezoelectric activity after proper electric polarization treatment, and is named as piezoelectric electret because of the characteristics of piezoelectric material and electret. The piezoelectric electret electroacoustic device is a device for performing electroacoustic/electroacoustic conversion by utilizing the piezoelectric effect or inverse piezoelectric effect of a piezoelectric electret material. The traditional capacitive/moving coil loudspeaker has a complex structure and requires extremely high-precision part matching design, and the piezoelectric electret electroacoustic device can greatly reduce the volume of the electroacoustic device, meanwhile, the number of parts is greatly reduced, the reliability is ensured, and the requirement of mass production is facilitated.
As shown in fig. 1, the piezoelectric electret electroacoustic device of the present application includes a vibration unit 10, the vibration unit 10 including a flexible lower electrode 11 and a multilayer piezoelectric electret film 12 and a flexible upper electrode 13 which are laminated, the multilayer piezoelectric electret film 12 being bonded between the flexible lower electrode 11 and the flexible upper electrode 13.
The piezoelectric electret electroacoustic device of the present application may be implemented as a loudspeaker, for example.
In some alternative embodiments, the piezoelectric electret electroacoustic device further comprises: and an annular connection member 14 connected to the periphery of the vibration unit 10. Here, the ring-shaped connection member 14 may be an adhesive material that is attachable and configured to attach the piezoelectric electret electroacoustic device to a preset location on a certain object or surface of the device.
In some alternative embodiments, the piezoelectric electret electroacoustic device further comprises: an insulating ring 15 separating the multilayer piezoelectric electret film 12 and the ring member 14. Here, the lower end face and the upper end face of the insulating ring 15 may be bonded to the flexible lower electrode 11 and the flexible upper electrode 13, respectively, and the inner side face and the outer side face contact the multilayer piezoelectric electret film 12 and the ring member 14, respectively.
In some alternative embodiments, the upper surface of the flexible upper electrode 13 is coplanar with the upper end surface of the annular connector 14, and the lower surface of the flexible lower electrode 11 is coplanar with the lower end surface of the annular connector 14.
In some alternative embodiments, the multilayer piezoelectric electret films 12 are connected in series (tandem connection).
In some alternative embodiments, the multilayer piezoelectric electret film 12 includes n layers of piezoelectric electret films 12, where n is a positive integer not less than 3 or 4 or 5.
In some alternative embodiments, the piezoelectric electret electroacoustic device of the present application, the piezoelectric electret film 12 may be a porous polymer piezoelectric electret film. Further, the porous polymeric piezoelectric electret film includes, but is not limited to, a polypropylene (PP) film. Further, the porous polymeric piezoelectric electret film may contain honeycomb-shaped lenticular holes inside. Further, the thickness of the porous polymeric piezoelectric electret film may be between 30 microns and 80 microns.
In some alternative embodiments, other materials may be tried, such as PTFE (polytetrafluoroethylene), FEP (fluorinated ethylene propylene copolymer)/PTFE composite films, and the like.
The piezoelectric electret electroacoustic device is manufactured by utilizing the inverse piezoelectric effect of piezoelectric electret materials, and the working principle of the piezoelectric electret electroacoustic device is as follows.
Taking the acoustic-electric conversion as an example, the sensitivity M of the piezoelectric electret electroacoustic device is:
the piezoelectric electret film contains honeycomb convex lens type holes inside. In the formula (1), s 1 Sum s 2 The total thickness of all solid layers in the piezoelectric electret film and the total thickness of the air gap layer in the hole, epsilon and epsilon, respectively 0 The relative dielectric constant and the absolute dielectric constant are respectively, namely, the absolute dielectric constant is the dielectric constant of the piezoelectric electret material, and the relative dielectric constant is the comprehensive dielectric constant of the piezoelectric electret material and the air inside the piezoelectric electret material. d, d 33 Is the piezoelectric coefficient and refers to the ratio of the amount of charge that a material generates under pressure to the pressure applied to the material. d, d 33 The larger the value of (c), the stronger the piezoelectric effect of the material, which can yield a larger charge amount and higher sensitivity.
The sensitivity of piezoelectric electret electroacoustic devices can be improved by several approaches:
the first approach is to use a multilayer film process by increasing the number of layers of piezoelectric electret films, i.e. several layers of piezoelectric electret films are connected in series or in parallel, the series connection being aimed at increasing the thickness of the film and the parallel connection being aimed at increasing the amount of electricity, and finally the purpose of increasing d 33 Coefficients.
In the formula (2), epsilon is the relative dielectric constant of the piezoelectric electret film, s 1 Sum s 2 The total thickness of all solid layers in the piezoelectric electret film and the total thickness of the air gap layer in the hole, s is the total thickness of the piezoelectric electret film, s=s 1 +s 2 ，s 2i Is the thickness of the ith air gap layer (the ith honeycomb lenticular holes), Σs 2i ＝s 2 ，σ i Is the charge density of the i-th layer surface, and Y is the Young's modulus of the honeycomb film material.
The second approach is to increase the area of the membrane (piezoelectric electret film) by changing the structural design.
Above, the present application proposes a piezoelectric electret electroacoustic device. The piezoelectric electret electroacoustic device is different from the traditional design of piston motion, and is replaced by a vibrating film (a plurality of piezoelectric electret films 12) with almost random vibration instead of regular vibration on the whole surface.
The piezoelectric electret electroacoustic device may be applied or otherwise disposed with its adhesive material in a position on a surface of a predetermined object/device, after being excited by an electrical signal, the multilayer piezoelectric electret film 12 is excited by the electrical signal, and the piezoelectric electret film 12 is mechanically vibrated by the inverse piezoelectric effect, thereby having an electro-acoustic transformed vibration effect.
At this time, each of the area units on the honeycomb face of the piezoelectric electret film 12 is capable of random vibration independently of each other, so that the entire honeycomb panel can be considered as an array of micro-speakers. Each micro-speaker unit radiates an uncorrelated signal, but their signals are finally combined together to macroscopically form the desired output. Thus, the signal excitation drives the surface of the object/device contacted with the signal excitation to vibrate and have acoustic signal output, and the purpose of electro-acoustic conversion by using the inverse piezoelectric effect driving of the piezoelectric electret film material is achieved.
The piezoelectric electret electroacoustic device has the main characteristics that:
(1) the inverse piezoelectric effect of the piezoelectric electret film is used for driving to perform electro-acoustic conversion.
(2) Electroacoustic conversion is performed by using multi-layer piezoelectric electret films to drive in series.
(3) Further, the periphery of the piezoelectric electret electroacoustic device is provided with a sticky material, so that the piezoelectric electret electroacoustic device can be stuck to a position of a certain surface of a preset device (object) and can drive the surface to vibrate and sound.
The piezoelectric electret electroacoustic device of the application has the technical effects that:
(1) the piezoelectric electret electroacoustic device is of a piezoelectric electret electroacoustic device, compared with a traditional capacitive/moving coil structure, the volume of the electroacoustic device can be greatly reduced, meanwhile, the number of parts is greatly reduced, reliability is guaranteed, and the requirement of mass production is facilitated.
(2) The porous polymer piezoelectric electret film (such as PP material) can reach very high piezoelectric coefficient, which is 1 order of magnitude higher than the piezoelectric activity of PVDF (polyvinylidene fluoride) ferroelectric polymer and copolymer thereof; secondly, the thickness of the porous polymer piezoelectric electret film can be small, the minimum thickness can be 30 microns, and the requirements on geometric dimensions are easily met; in addition, the porous polymer piezoelectric electret film has wide raw material sources, and the material cost and the processing preparation are much easier than those of piezoelectric ceramics and ferroelectric single crystal materials.
(3) The multilayer piezoelectric electret films are connected in series to drive to perform electroacoustic conversion, so that the piezoelectric effect can be improved, and higher sensitivity can be realized.
(4) Furthermore, the piezoelectric electret electroacoustic device can be adhered to a certain surface of a preset device (object) by using an adhesive material of the piezoelectric electret electroacoustic device, and can drive the surface to vibrate and sound, so that the piezoelectric electret electroacoustic device has wide application scenes.
In addition, it should be noted that the derivative products manufactured by using the principles of the present application, and the novel products and similar structures that can be designed by using the principles and integrating with the microelectronic device are also included in the protection scope of the present application.
The technical scheme of the application is described in detail through the specific embodiments. In the foregoing embodiments, the descriptions of the embodiments are each focused, and for those portions of one embodiment that are not described in detail, reference may be made to the related descriptions of other embodiments.
It should be understood that the above embodiments are merely illustrative of the technical solutions of the present application, and not limiting thereof. Modifications of the technical solutions described in the above embodiments or equivalent substitutions of some technical features thereof may be made by those skilled in the art; such modifications and substitutions do not depart from the spirit and scope of the corresponding technical solutions.
Claims (10)
1. The piezoelectric electret electroacoustic device is characterized by comprising a vibrating unit formed by a flexible lower electrode, a plurality of layers of piezoelectric electret films and a flexible upper electrode which are arranged in a stacked mode, wherein the plurality of layers of piezoelectric electret films are adhered between the flexible lower electrode and the flexible upper electrode, and the plurality of layers of piezoelectric electret films are connected in series.
2. The piezoelectric electret electroacoustic device of claim 1 further comprising: and the annular connecting piece is connected to the periphery of the vibration unit.
3. The piezoelectric electret electroacoustic device of claim 2 wherein the annular connector is a bondable adhesive material.
4. The piezoelectric electret electroacoustic device of claim 2 further comprising: an insulating ring separating the multilayer piezoelectric electret film and the ring member.
5. The piezoelectric electret electroacoustic device of claim 4 wherein the lower end face and the upper end face of the insulating ring are bonded to the flexible lower electrode and the flexible upper electrode, respectively.
6. The piezoelectric electret electroacoustic device of claim 2 wherein the upper surface of the flexible upper electrode and the upper end face of the annular connector are coplanar and the lower surface of the flexible lower electrode and the lower end face of the annular connector are coplanar.
7. The piezoelectric electret electroacoustic device of any of claims 1 to 6 wherein the piezoelectric electret film is a porous polymeric piezoelectric electret film.
8. The piezoelectric electret electroacoustic device of claim 8 wherein the porous polymeric piezoelectric electret film is a polypropylene film.
9. The piezoelectric electret electroacoustic device of claim 7 wherein the porous polymeric piezoelectric electret film comprises honeycomb lenticular holes therein.
10. The piezoelectric electret electroacoustic device of claim 7 wherein the thickness of the porous polymeric piezoelectric electret film is between 30 microns and 80 microns.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311175544.7A CN117395581A (en) | 2023-09-12 | 2023-09-12 | Piezoelectric electret electroacoustic device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311175544.7A CN117395581A (en) | 2023-09-12 | 2023-09-12 | Piezoelectric electret electroacoustic device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117395581A true CN117395581A (en) | 2024-01-12 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311175544.7A Pending CN117395581A (en) | 2023-09-12 | 2023-09-12 | Piezoelectric electret electroacoustic device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117395581A (en) |
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2023
- 2023-09-12 CN CN202311175544.7A patent/CN117395581A/en active Pending
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