89 results about "Ferroelectret" patented technology

The disclosed preparation method for a porous polymer piezoelectric electret film comprises: for the porous polymer film, overlaying polymer films with different melting points into a composite film with grid on one or two surfaces; forcing with pressure as 1-10MPa at some temperature for 2-120min; then charging the composite film by means of corona charge, contact charge or electron beam charge. This invention can obtain product with high thermal stability and voltage activity.

This invention relates to a preparation method for controllable micro-hole structure piezoelectric function films including the preparation of the controllable micro-hole structure polymer compound film and charging to the film, which overlaps the polymer densified films with high stable heat and polymer mesh films of different smelt temperatures alternately then processes them for a period of time to get the polymer compound film to be charged by a corona method, contact method or electronic beam method to get the piezoelectric function film.

The invention relates to an intelligent artificial hand system which comprises an artificial hand body, a drive motor, a piezoelectric electret, a control terminal and a signal interaction module. The artificial hand body comprises a plurality of finger knuckles controlled by the drive motor. The control terminal controls the artificial hand body to grasp according to a first myoelectric signal. The piezoelectric electret collects a tactile signal and a slip sense signal, the control terminal controls whether the artificial hand body continues grasping or not according to the signals, and the signal interaction module feeds back stimulation to a stump. The signal interaction module also obtains a third myoelectric signal, and the control terminal controls the artificial hand body to grasp further according to the third myoelectric signal. The control terminal also controls the artificial hand body to open according to a second myoelectric signal. The intelligent artificial hand system overcomes the defect that a traditional artificial hand can not feel motion states or motion trends of an object relative to the artificial hand and can not control and adjust grasping strength, and is high in reliability and safety, low in cost and easy to popularize.

The invention discloses a preparation method of a piezoelectric electret film. The preparation method comprises the following steps: coating a polymer coating on a template with nano wires, and drying; subsequently removing the template so as to obtain a first polymer film with nano wire holes; combining at least one first dried polymer film and a second polymer film so as to form a cavity; polarizing so as to distribute opposite charges on the upper and lower surfaces inside the cavity and form the piezoelectric electret film. The invention further discloses the piezoelectric electret film prepared by using the preparation method. The invention further provides the piezoelectric electret film which comprises a first polymer film layer with the nano wire holes, a second polymer film layer combined on the surface of the first polymer film layer with the nano wire holes, a cavity formed between the first polymer film layer and the second polymer film layer, and opposite charges distributed on the upper and lower surfaces through polarization, wherein the formation of the nano wire holes is achieved by coating the polymer solution on the nano wire template. The invention also provides a piezoelectric element formed by the electret film.

The invention discloses a method for raising a signal to noise ratio of a piezoelectric electret film sensor. A lamination method is employed to carry out series connection or parallel connection lamination on piezoelectric electret films, charge and voltage output quantity of the piezoelectric electret film sensor are raised by times so as to raise the sensitivity of the sensor. Simultaneously, the invention also discloses a screen printing method, and a flexible shielding layer is added to the piezoelectric electret film sensor so as to raise the anti-interference capability of the sensor. According to the invention, operation is simple, energy consumption is low, work efficiency is substantially raised, and under the premise of flexibility, being ultrathin, free bending, random cutting, durability, and a low price, the sensitivity and the anti-interference capability of the sensor are raised. Thus the application of the piezoelectric electret film sensor at a high sensitivity demand occasion and in a strong electromagnetic interference environment is developed, and the sensor caters to a market demand more.

The present invention relates to a method for producing two- or multi-layer ferroelectrets with defined voids, with the exception of three-layer ferroelectrets with a perforated middle layer made of PTFE between two FEP layers, involving, introducing one or more clearances into at least one surface side of a polymer film element by means of a method of removal, applying a first covering to the surface side of the polymer film element comprising clearances formed in step A), and joining the polymer film element and the covering to form a polymer film composite, the clearances being closed while voids are formed, and to a two- or multi-layer ferroelectret, with the exception of three-layer ferroelectrets with a perforated middle layer made of PTFE between two FFP layers, in particular produced by this method. The invention also relates to a piezoelectric element containing a ferroelectret multi-layer composite according to the invention.

The invention relates to a preparation method for a piezoelectric electret film. The method comprises the following steps: (1) spraying a polymer solution on a template with bulges for drying, and after drying, removing the template to obtain a first polymer film with concave pits; (2) combining the dried first polymer film with a second polymer film to form a cavity; (3) distributing opposite charges on the opposite surfaces in the cavity through polarization to form the piezoelectric electret film. The invention provides the piezoelectric electret film prepared through the method. The piezoelectric electret film comprises the first polymer film (1) with the concave pits, the second polymer film (3), the cavity (2) and the opposite charges, wherein the second polymer film (3) is combined with the surface with the concave pits of the first polymer film (1), and the cavity (2) is formed between the first polymer film (1) and the second polymer film (3); the opposite charges are distributed on the surfaces of the cavity through polarization. The concave pits are formed by coating the template with the bulges with the polymer solution.

The invention discloses a plantar pressure distribution detection system which comprises a detection layer and a processing sending module, wherein the detection layer is configured to detect plantar pressure signals and converts the detected plantar pressure signals into electric signals; the processing sending module is configured to receive the electric signals converted by the detection layer, process the received electric signals and send the processed electric signals to an external receiving device. The invention further discloses a manufacturing method of the plantar pressure distribution detection system. According to the plantar pressure distribution detection system and the manufacturing method of the plantar pressure distribution detection system, a piezoelectric electret used by the system and the method has the advantages of being light, thin and soft, the piezoelectric response is large, the linearity is high, influences of temperature changes within the work temperature range are small, influences of shearing force are small, no influence of bending exits, and thus the plantar pressure distribution detection system and the manufacturing method of the plantar pressure distribution detection system are suitable for real-time detection of plantar pressure distribution.

The invention belongs to the technical field of piezoelectric function materials, and particularly relates to a method for producing piezoelectric electret functional films with piezoelectric coefficient d31. The method comprises the steps that non-polar polymer materials form thin polymer films on the surface of a template having grooves through impressing, spray-coating, lifting or spin-coating, the shape of the thin films is the same with that of the template structure, and the thickness of the thin films is between 1mu m and 200mu m; porous structure composite films on which grooves and dense portions are arranged alternately are obtained through hot-pressing bonding of two polymer films having the same structure; and finally the composite films are polarized via a corona charging process or a contact charging process so as to obtain the piezoelectric electret functional films. The piezoelectric electret having grooves obtained through the method has the high piezoelectric coefficient d31 (or d32). The piezoelectric electret functional films can be applied in the fields such as energy collectors, acoustoelectric sensors, robot skins, intelligent structures, opto-acoustic sensors and the like.

The invention discloses a method of manufacturing a closed porous piezoelectret energy harvester based on nanoimprint. Manufacturing and processing of an imprint mold are firstly carried out; preparation of a piezoelectret thin film is then carried out; imprint and demolding are carried out to obtain a porous thin film of the piezoelectret; multiple porous thin films are bonded to form a multilayer closed porous film; corona electret is carried out; and finally, working electrode sputtering at two ends of the multilayer closed porous film is carried out. The closed porous cavity can greatly improve the charge storage intensity and the stability, the multilayer porous structure can improve the electro-mechanical conversion efficiency, and the output of the energy harvester is improved.

Thermally stable piezoelectric polymer foams (ferroelectrets) with high piezoelectric activity for sensing and actuation. The invention further includes a method of fabricating such foams in an environmentally friendly manner.

An embodiment of the invention discloses a pulse detection device and a manufacturing method thereof. The pulse detection device comprises: a piezoelectric sensing layer including a flexible piezoelectric electret film and two metal electrodes arranged on the upper and lower surfaces of the flexible piezoelectric electret film respectively, wherein the two metal electrodes are used for outputtingcharge quantity changes when the flexible piezoelectric electret film deforms; a data processing mechanism used for connecting the two metal electrodes to receive charge quantity changes output by thetwo metal electrodes, for determining a potential change according to the charge quantity changes, and for transmitting the potential change to a data receiving terminal. The technical problem that apulse detection device of the prior art has complex structure is solved; structural complexity of the pulse detection device is decreased.

The invention relates to a film speaker array, which comprises a piezoelectric electret film and a circuit board assembly, wherein the piezoelectric electret film is a porous polymer film, and electrode arrays are respectively and correspondingly arranged on two sides of the piezoelectric electret film; a speaker circuit, and a circuit board input end and a circuit board output end which are electrically connected with a speaker circuit are arranged on the circuit board assembly, and the circuit board output end is electrically connected with electrode arrays arranged on two sides of the piezoelectric electret film. The film speaker array made of porous polymer film is integrated with the advantage of high directivity of the speaker array and the advantages of lightness, thinness, softness, simple structure, high reliability and low cost of the polymer piezoelectric electret, and greatly expands the application range of the speaker array, thereby being an alternative replacing the traditional speaker array in the theater, the meeting place, the classroom, the museum, the gymnasium and other circumstances.

The invention relates to a producing method of a piezoelectric electret film, and the producing method is as follows: fluorinated ethylene propylene copolymer films and polytetrafluoroethylene films are alternately laminated together, and then placed on a substrate, after the alternate lamination, two outermost layers are the polytetrafluoroethylene films; a latticed pressing plate is arranged on an outermost layer t polytetrafluoroethylene film opposite the substrate, pressure is applied to the pressing plate, the alternately laminated structure of the fluorinated ethylene propylene copolymer films and the polytetrafluoroethylene films is heated, after cooling, the pressing plate and the substrate are removed to obtain the piezoelectric electret film provided with micropores in the middle. In the production process of the piezoelectric electret film, through selection of latticed pressing plates with different specifications, such as regulation of mesh net opening mesh number, wire diameter, shape and other parameters and thermal bonding process parameter of the pressing plates, the fine adjustment of microporous structure of the piezoelectric electret film can be realized, and the producing method is strong in practicability, and can be widely popularized and applied. In addition, the invention also relates to the piezoelectric electret film produced by the producing method.

The invention discloses a wrist type pulse wave monitoring device which is characterized in that the wrist type pulse wave monitoring device comprises a piezoelectric electret film sensor, a packaging component, shielding lines, a wrist belt and a processing circuit; the piezoelectric electret film sensor adheres to the packaging component; two electrodes of the piezoelectric electret film sensor are led out through the shielding lines and connected to an input end of the processing circuit, and an output end of the processing circuit is led out through one shielding line and connected to an external electronic device; the piezoelectric electret film sensor, the packaging component, the processing circuit and the shielding lines connecting the processing circuit and the piezoelectric electret film sensor are all sewn in the wrist belt. According to the wrist type pulse wave monitoring device, the sampling flexibility of pulse waves is high, extraction is easy and not prone to distortion, and the wrist type pulse wave monitoring device can be used for pulse-taking monitoring easily.

The invention discloses a signal detection sensing structure and a manufacturing method thereof, and a signal detection method. The signal detection sensing structure comprises a first piezoelectric electret layer, a second piezoelectric electret layer and a bonding layer located between the first piezoelectric electret layer and the second piezoelectric electret layer. One side surface of the first piezoelectric electret layer, which is far away from the second piezoelectric electret layer, comprises a plurality of embossment structures. One side surface of the second piezoelectric electret layer, which is close to the first piezoelectric electret layer, is a smooth surface. The first piezoelectric electret layer is used for detecting a contact signal and / or a slide signal of a touch object. The second piezoelectric electret layer is used for detecting a contact signal of the touch object. Through a lamination structure of the first piezoelectric electret layer and the second piezoelectric electret layer, a single sensing unit can simultaneously detect the contact signal and the slide signal. By using the signal detection sensing structure, the structure is simple; sensitivity is high; there is no pyroelectric effect; in a work temperature range, the structure is not influenced by temperature changes; and high precision detection of the contact signal and the slide signal can be realized.

The invention discloses a piezoelectret structure, which comprises a first electret film, a second electret film, a first adhesive layer and an electrode, wherein a plurality of first grooves distributed in arrays are formed in the surface of the first electret film; electric charges with opposite polarities are stored in the first and second electret films after the first and second electret films are polarized respectively; the surface, adjacent to groove openings of the first grooves, of the first electret film is coated with the first adhesive layer which is used for combining the first and second electret films; the first grooves form regular and ordered hole structures after the first and second electret films are combined. The piezoelectret structure is formed sequentially by polarization and combination, so that bulk charges of which the polarity is opposite to that of the electric charges on the surface close to the hole structures can be prevented from being generated on a surface layer of the piezoelectret structure; in addition, the first and second electret films of the piezoelectret structure are combined in an adhesion way, so that inner electric charge loss caused by the high temperature of heat fusion is avoided. In addition, the invention provides a method for preparing the piezoelectret structure.

The invention relates to double-purpose thin film equipment for sound transmission and extension, comprising a piezoelectric electret thin film and a circuit board assembly; the piezoelectric electret thin film includes a porous polymer thin film, electrodes symmetrically installed at the two sides of the porous polymer thin film, and a thin film connection end electrically connected with the electrodes; positive and negative charges are respectively deposited on the upper and lower surfaces of a hole on the porous polymer thin film; and a first connection end electrically connected with the thin film connection end and a second connection end connected with an external circuit are installed on the circuit board assembly. The positive and negative charges are deposited on the upper and lower surfaces of the hole on the porous polymer thin film so as to form an electric dipole; under the influence of the pressure of sound wave, the thickness of the hole on the piezoelectric film changes, such that the size of the electric dipole in the hole changes, and compensation charges in the electrodes also change; therefore, the voltage between the electrodes changes, namely acoustoelectric conversion is realized by using a piezoelectric effect; and vice versa, the thickness of the piezoelectric film vibrates according to a reciprocal piezoelectric effect, the sound wave is generated, and the electroacoustic conversion is realized.

The invention relates to a flexible tactile sensor. The sensor comprises a piezoelectric electret cable sensing unit and a piezoelectric film sensing unit which are conductively connected with each other, the piezoelectric electret cable sensing unit comprises a core electrode, a piezoelectric electret layer, a shielding layer and a sheath protection layer which are coaxially connected in sequencefrom inside to outside; wherein the piezoelectric film sensing unit comprises a first electrode layer, a piezoelectric material layer and a second electrode layer which are longitudinally distributedand sequentially connected, the shielding layer is connected with a piezoelectric cable grounding lead, the first electrode layer is connected with a first electrode lead of a piezoelectric film, andthe second electrode layer is connected with a second electrode lead of the piezoelectric film. Compared with the prior art, normal stress and shear stress can be measured at the same time.

The present invention discloses a passive highly-sensitive impact sensor based on piezoelectrets and a testing method thereof. Electret layers are arranged on a back electrode and a spring electrode, a cavity is formed between a spring electrode electret layer and a back electrode electret layer, and a pair of piezoelectrets is formed. The surfaces of the piezoelectrets have opposite polarization charges, and a macroscopic dipole is between the spring electrode electret layer and the back electrode electret layer. Under an external force, a macroscopic dipole distance is changed, an impact type voltage spike signal is formed, and the external force is obtained through measuring voltage. According to the sensor and the method, a special impact force structure mode is used to provide impact voltage, the sensitivity can reach 80V / 1MPa, and the sensor has the characteristics of high impact, high load, high sensitivity and the like. An external power supply is not needed, the sensor is self-powered and without paranoid voltage, the passive operation is achieved, and the sensor has the characteristics of low consumption and high efficiency and ultra high sensitivity in the current impact sensor power generation technology.

The invention belongs to the technical field of a piezoelectric functional material, and particularly relates to a preparation method of a functional film of a flexible cross-linked polypropylene piezoelectric electret, which comprises the specific steps of: using a cross-linked polypropylene porous material, adjusting a micro structure and physical properties of a thin film by a hot drawing or / and hot pressing process, polarizing the thin film by a corona charging or contact charging process, thereby obtaining the required functional film of the piezoelectric electret. The prepared piezoelectric electret not only has strong piezoelectric effects but also has flexible characteristics. The functional film of the piezoelectric electret can be applied to such fields as robot skin, artificial muscles, intelligent clothing, intelligent structures, energy collectors and acoustical-electrical sensors.

The invention discloses an MEMS technology preparation method of a piezoelectret matrix. According to the preparation method, a standard MEMS micromachining process is used, and a first photoetching plate is used to form a groove with a high aspect ratio, and the groove is filled with functional piezoelectret matrix material; a second photoetching plate is used to form an opening window, and the piezoelectret matrix under the opening window is finally released so as to achieve consistency and controllability of the shape of the hole on the piezoelectret, wherein the minimum controllable size is in 1 microns magnitude. The preparation method of the invention can efficiently prepare the multilayer piezoelectret matrix in a film thickness direction, and the number of layers is not less than 50. The preparation method of the invention achieves the goal of freely and flexibly adjusting the geometric dimension of the hole and the number of layers and the geometric dimension of the piezoelectret matrix by designing the photoetching plate.

A piezoelectric electret film comprises an input layer, a base material layer and a grounding layer, wherein the input layer is made of metal materials and used for feeding electrodes; the base material layer is made of porous polymer materials and treated in the electret mode, and charges are arranged in the base material layer; the grounding layer is made of metal materials and used for grounding; and the input layer, the base material layer and the grounding layer are laminated sequentially. When the piezoelectric electret film is applied to a microphone, the base material layer containing charges is not arranged on the surface of the piezoelectric electret film, so that even when the surface of the piezoelectric electret film is wet, the base material layer cannot be contacted with water directly, and the charges on the piezoelectric electret film can be effectively prevented from being lost. Simultaneously even when the surface of the base material layer is wet, the charges are stored in the base material layer, so that the charges cannot be directly contacted with the water, and further the charges can be prevented from being lost. The invention further provides a piezoelectric electret microphone using the piezoelectric electret film.

The invention discloses a piezoelectric electret film key. The piezoelectric electret film key is characterized in that a piezoelectric electret film is adopted as a force sensitive element of the key; a plurality of key areas are arranged on the piezoelectric electret film; the upper surface and the lower surface of the piezoelectric electret film are coated with upper surface electrodes and lower surface electrodes which are vertical to the key areas and are in one-to-one correspondence with the key areas; the outer layers of the upper surface electrodes are covered with one surface layer; the lower surface electrodes are bonded on a key base layer; an upper surface encapsulation layer is arranged between the surface layer and the upper surface electrodes; a lower surface encapsulation layer is arranged between the lower surface electrodes and the base layer; and a shielding layer is arranged between the lower surface encapsulation layer and the base layer. The piezoelectric electret film key is advantageous in high sensitivity and strong stability. The piezoelectric electret film key is flexible and can be bent freely, and can identify key pressing strength and has functions such as sliding control.

The invention belongs to the field of sensing technology, and to an electret transistor force sensor with a dynamic and static force monitoring function and a preparation method thereof. The electrettransistor force sensor is composed of an electret material and a semiconductor material. The electret deforms on the condition of an external force function, thereby causing a polarization state change, and furthermore causing change of source leakage current. Through detecting the source leakage current, monitoring to a static force and a dynamic force is realized. The electret transistor forcesensor and the preparation method thereof settle a problem of high difficulty in performing (quasi)static force monitoring on an electret capacitor. The electret transistor force sensor and the preparation method have advantages of simple preparation method, high sensitivity and high suitability for application in various fields with a force monitoring / detecting requirement.

The invention discloses an integrated panel piezoelectric keyboard, comprising a piezoelectric electret film, an upper conductive electrode layer and a lower conductive electrode layer tightly attached to the two opposite side surfaces of the piezoelectric electret film, and an integrated panel, wherein the integrated panel includes a key area and a non-key area, the key area is provided with a plurality of keys, the upper conductive electrode layer comprises a plurality of upper key conductive electrodes corresponding to the plurality of keys and an upper misoperation conductive electrode corresponding to the non-key area, and the lower conductive electrode layer comprises a plurality of lower key conductive electrodes corresponding to the plurality of keys and a lower misoperation conductive electrode corresponding to the non-area area. According to the integrated panel piezoelectric keyboard, the key electrodes and the misoperation electrodes all output charge through different lines, the keyboard judges whether there is misoperation through the line of the received charge; the integrated panel piezoelectric keyboard is accurate in judgment, simple in structure, low in cost, and convenient to use in occasions where the keys are easy to pollute.

The invention provides a piezoelectric electret material assembly. The assembly comprises a piezoelectric electret layer, a metal positive electrode layer and an insulating layer which are arranged sequentially; the metal positive electrode layer comprises a plurality of independent metal electrode units and a connection electrode, wherein the metal electrode units are repeatedly disposed, and theconnection electrode is in conductive connection with all the metal electrode units. The piezoelectric electret material assembly of the invention has electric fields with opposite directions. The piezoelectric electret material assembly is prepared at first, and the prepared piezoelectric electret material assembly is polarized, and therefore, the probability of dust accumulation on the surfaceof the material can be decreased. The piezoelectric electret material assembly has the advantages of simple structure, convenient preparation, simple process and high efficiency, and is suitable for mass production in factories.

The invention relates to a thin film type microphone array, comprising a piezoelectric electret thin film and a circuit board component, wherein the piezoelectric electret thin film is a porous thin polymer film; electrode arrays are correspondingly arranged at two sides of the piezoelectric electret thin film; a microphone circuit as well as a circuit board input end and a circuit board output end electrically connected with the microphone circuit are arranged on the circuit board component; and the circuit board input end is electrically connected with the electrode arrays at two sides of the piezoelectric electret thin film. In the thin film type microphone array, a piezoelectric electret made of the porous thin polymer film is adopted as a microphone unit, thereby combining the advantage of efficient reception of the microphone array with the advantages of lightness, thinness, softness, simple structure, strong reliability, low cost and the like of the polymer piezoelectric electret, therefore, the application range of the microphone array is greatly widened, and the microphone array becomes one of choices for replacing a traditional microphone array in the environment of video conferences, vehicle-mounted audio systems, large-scale meeting houses and the like.

The invention discloses a sensor and a method for preparing the same. The sensor comprises a piezoelectric electret sensor, a piezoresistive sensor, a protection member and a buffer layer, wherein thebuffer layer is disposed between the piezoelectric electret sensor and the piezoresistive sensor; and the piezoelectric electret sensor, the piezoresistive sensor and the buffer layer are embedded inthe protection member. Embodiments of the present invention improve the accuracy of a tactile sensor for detecting a tactile signal.