A method for preparing a piezoelectric sensor and a piezoelectric sensor

Abstract

The present application discloses a method for preparing a piezoelectric sensor and a piezoelectric sensor. The preparation method includes: providing a piezoelectric electret; disposing a signal array unit on one side surface of the piezoelectric electret; disposing an insulating layer on the area of the piezoelectric electret surface not covered by the signal array unit; making a signal conductor on the insulating layer and connecting the signal conductor to the signal array unit; and disposing a ground layer and a ground conductor on the side surface of the piezoelectric electret away from the signal array unit to obtain a piezoelectric sensor. Through the above-mentioned method, the present application can reduce the restrictions on the size of the piezoelectric sensor caused by the number and size of the sensing units, and reduce the impact of the number and size of the sensing units on the detection accuracy. By increasing the density of the array units in the sensor, the precision and accuracy of the sensing signal can be further improved.

Description

Technical Field

[0001] The present application relates to the technical field of functional materials, and in particular to a preparation method of a piezoelectric sensor and a piezoelectric sensor. Background Art

[0002] Piezoelectric electret is a new functional material with a high piezoelectric coefficient and good flexibility. Its high sensitivity to dynamic force detection holds great potential for applications in fields such as sensors. Sensors based on piezoelectric electrets are thin and flexible, and are suitable for applications in robotics, artificial skin, and other fields.

[0003] In practical applications, piezoelectric electret sensors are often used to detect forces such as touch, vibration, and friction. In existing technologies, if it is necessary to simultaneously detect changes in tactile, vibration, and frictional forces at multiple locations, or to improve the precision and accuracy of dynamic force detection, piezoelectric electret sensors are typically designed into an array structure. For example, multiple discrete piezoelectric electret sensing units are arranged and combined into a sensor array. While this method has a simple preparation process, if used to prepare sensors with high-density array structures, the size and detection accuracy of the resulting sensor will be limited and affected by the size of the discrete sensing units. Summary of the Invention

[0004] The main technical problem solved by the present application is to provide a method for preparing a piezoelectric sensor and a piezoelectric sensor, by preparing a signal array unit and a signal wire on a complete electret film, thereby avoiding the failure of the piezoelectric effect of the sensing unit.

[0005] In order to solve the above technical problems, a technical solution adopted in the present application is to provide a method for preparing a piezoelectric sensor, which includes: providing a piezoelectric electret; setting a signal array unit on one side surface of the piezoelectric electret; setting an insulating layer in the area of the piezoelectric electret surface not covered by the signal array unit; making a signal wire on the insulating layer and connecting the signal wire to the signal array unit; setting a ground layer and a ground wire on the side surface of the piezoelectric electret away from the signal array unit to obtain a piezoelectric sensor.

[0006] Among them, the step of setting a signal array unit on one side surface of the piezoelectric electret specifically includes: preparing a signal layer mask plate based on the set parameters of the signal array unit; placing the signal layer mask plate on one side surface of the piezoelectric electret, and controlling the deposition of metal particles onto the surface of the piezoelectric electret to form a signal array unit.

[0007] Among them, the step of setting an insulating layer in the area of the piezoelectric electret surface not covered by the signal array unit specifically includes: preparing a signal layer cover plate based on the set parameters of the signal array unit; after using the signal layer cover plate to cover the signal array unit, controlling the high molecular polymer particles to be deposited on the piezoelectric electret surface to form an insulating layer.

[0008] Among them, the steps of arranging signal wires on the insulating layer and connecting the signal wires to the signal array unit specifically include: preparing a signal wire mask plate connected to the signal array unit based on the signal array unit; placing the signal wire mask plate on the signal array unit and the insulating layer, and controlling the deposition of metal particles on the surfaces of the signal array unit and the insulating layer to form a signal wire connected to the signal array unit.

[0009] Among them, the steps of setting a ground layer and a ground wire on the side surface of the piezoelectric electret away from the signal array unit to obtain a piezoelectric sensor specifically include: controlling the deposition of metal particles on the side surface of the piezoelectric electret away from the signal array unit to form a ground layer; wherein the position of the ground layer corresponds to the position of the signal array unit so that the ground layer covers the signal array unit; preparing a ground wire mask plate based on the connection method between the ground wire and the ground layer; placing the ground wire mask plate on the surface of the piezoelectric electret where the ground layer is located, and controlling the deposition of metal particles on the surface of the piezoelectric electret to form a ground wire connected to the ground layer, so as to obtain a piezoelectric sensor.

[0010] The step of providing a piezoelectric electret specifically includes: preparing a polymer film, processing the polymer film so that the polymer film has a microporous structure; and polarizing the polymer film with the microporous structure so that two opposite walls of the microporous structure have space charges with opposite polarities.

[0011] The polymer film is a high molecular polymer with excellent dielectric properties.

[0012] The metal particles are metals with good electrical conductivity.

[0013] The high molecular polymer particles are high molecular polymers with insulating properties.

[0014] To solve the above-mentioned technical problems, another technical solution adopted by the present invention is to provide a piezoelectric sensor, which includes: a piezoelectric electret; a signal array unit, which is arranged on one side surface of the piezoelectric electret; an insulating layer, which is arranged in an area of the piezoelectric electret surface not covered by the signal array unit; a signal wire, which is arranged on the insulating layer and connected to the signal array unit; a ground layer and a ground wire, which are arranged on one side surface of the piezoelectric electret away from the signal array unit.

[0015] The beneficial effects of this application are as follows: Unlike existing technologies, the piezoelectric sensor preparation method provided in this application does not damage the integrity of the piezoelectric electret. The piezoelectric electret is a complete, non-discrete, integral thin film, and is therefore not limited by the size of the separate sensing units, nor is its structure damaged. Furthermore, the signal conductors are disposed on the insulating layer of the piezoelectric electret, which does not affect the installation of the piezoelectric sensor. Through this approach, this application can reduce the size restrictions imposed by the number and size of sensing units on the piezoelectric sensor, as well as the impact of the number and size of sensing units on detection accuracy. By increasing the density of the array units in the sensor, the precision and accuracy of the sensing signal can be further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a flow chart of an embodiment of a method for preparing a piezoelectric sensor of the present application;

[0017] Figure 2 yes Figure 1 Step S11 is a sub-flowchart of a preferred embodiment;

[0018] Figure 3 yes Figure 1 Sub-flowchart of step S12-preferred embodiment;

[0019] Figure 4a and Figure 4b It is a schematic diagram of the structure of the signal array unit of the present application at various preparation stages;

[0020] Figure 5 yes Figure 1 Sub-flow chart of step S13-preferred embodiment;

[0021] Figure 6a and Figure 6b It is a schematic diagram of the structure of the insulating layer of the present application at various preparation stages;

[0022] Figure 7 yes Figure 1 Sub-flow chart of step S14-preferred embodiment;

[0023] Figure 8a and Figure 8b is a schematic structural diagram of the signal conductor after the coating process is completed in step S72;

[0024] Figure 9 yes Figure 1 Step S15 is a sub-flowchart of a preferred embodiment;

[0025] Figure 10 1 is a schematic cross-sectional view of an embodiment of a piezoelectric sensor of the present application;

[0026] Figure 11is a top view of an embodiment of a piezoelectric sensor of the present application;

[0027] Figure 12 It is a bottom view of one embodiment of the piezoelectric sensor of the present application. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0029] The terms used in the examples of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The singular forms "a," "the," and "the" used in the examples of this application and the appended claims are also intended to include plural forms. Unless otherwise clearly indicated above, "a plurality" generally includes at least two, but does not exclude the inclusion of at least one.

[0030] It should be understood that the term "and / or" as used herein is merely a description of the relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0031] It should be understood that the terms "comprises," "comprising," or any other variations used herein are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0032] Piezoelectric electret is a new functional material that combines piezoelectric and electret properties. It typically uses a polymer matrix with metal electrodes plated on the surface. The piezoelectricity of this material stems from the unique closed pore structure within the polymer and the oppositely polarized space charges deposited on the opposite walls of these pores. Its structure lacks the inherent electric dipole found in traditional inorganic piezoelectric materials and organic piezoelectric polymers.

[0033] The working principle of the piezoelectric electret is that the microporous structure storing electric charges (dipoles) deforms under the action of external force, changing the electric dipole moment, causing the compensation charge in the metal electrode plated on the polymer film to change, thereby showing the corresponding charge or voltage signal to the outside, and transmitting the piezoelectric effect to the external processor.

[0034] This polymer-based piezoelectric electret exhibits an extremely high piezoelectric coefficient while sharing the common properties of polymer materials, such as light weight, thinness, high toughness, flexibility, adaptability to various environments, and acoustic impedance matching that of the human body and water. Therefore, due to these advantages, piezoelectric electrets have broad application prospects in high-end acoustics, artificial intelligence, biosensing, security, and medical fields.

[0035] While typical resistor and capacitor sensors have good sensitivity for detecting static forces, the signal characteristics of sensors based on piezoelectric electrets for dynamic force detection are as follows: as a finger presses the sensor, the force exerted by the finger on the sensor gradually increases, at which point the sensor outputs a spike-like signal; when the force exerted by the finger on the sensor stabilizes, the sensor output signal is zero; as the finger releases the sensor, the force exerted by the finger on the sensor gradually decreases to zero, at which point the sensor outputs a spike in the opposite direction of the spike output by the finger. Therefore, compared to resistor and capacitor sensors, and sensors based on traditional piezoelectric materials such as piezoelectric ceramics, piezoelectric electret sensors not only have high sensitivity for dynamic force detection, but also have a higher piezoelectric coefficient and good flexibility.

[0036] In practical applications, piezoelectric electret sensors are often used to detect forces such as touch, vibration, and friction. To simultaneously detect changes in tactile, vibration, and frictional forces at multiple locations, or to improve the precision and accuracy of dynamic force detection, piezoelectric electret sensors are typically designed as arrays. For example, multiple discrete piezoelectric electret sensing units are combined into a piezoelectric sensor array.

[0037] Specifically, metal electrodes are plated on corresponding locations on the upper and lower sides of a piezoelectric electret film to create a piezoelectric electret sensor unit. Multiple discrete piezoelectric electret sensor units are combined to form a piezoelectric electret sensor array. While this method for fabricating an array sensor is simple, if used to create a high-density array sensor, the resulting sensor's size and detection accuracy will be limited and affected by the size of the discrete sensor units.

[0038] For example, the required piezoelectric sensor has a high-density array structure. If the size of the discrete sensing units is large, the number of sensing units in the array will be small, and the dynamic force at each position cannot be accurately detected. If the size of the discrete sensing units is small, a large number of sensor units will be required to form the array. The piezoelectric electret film in the array sensor is composed of multiple fragmented films, which will affect the flexibility of the sensor array and, accordingly, reduce the precision and accuracy of its dynamic force detection. Therefore, when the size of the sensor array is limited, the number of discrete sensing units in the sensor array is limited by the size of the discrete sensing units, which further affects the precision and accuracy of multi-position dynamic force detection.

[0039] At the same time, since each sensor unit in the array sensor needs to be connected to a signal output wire, as the number of sensor units increases, the number of signal output wires of the array sensor also increases. Since the size of the sensor unit is small, in order not to affect the detection, the distance between the sensor units is also small. It is a more difficult operation to install and connect multiple wires in a smaller space, which is not conducive to the installation of the array sensor. It is also impossible to output the piezoelectric effect detected by the sensor unit to the outside through the wire, which has a relatively large impact on the sensor signal processing circuit.

[0040] Based on the above situation, the present application provides a method for preparing a piezoelectric sensor and a piezoelectric sensor, which avoids the failure of the piezoelectric effect of the sensing unit by preparing a signal array unit and a signal wire on a complete electret film.

[0041] The method for preparing a piezoelectric sensor provided in the present application includes: providing a piezoelectric electret; arranging a signal array unit on one side surface of the piezoelectric electret; arranging an insulating layer in an area of the piezoelectric electret surface not covered by the signal array unit; making a signal wire on the insulating layer and connecting the signal wire to the signal array unit; and arranging a ground layer and a ground wire on a side surface of the piezoelectric electret away from the signal array unit to obtain a piezoelectric sensor.

[0042] A piezoelectric sensor provided in the present application includes: a piezoelectric electret; a signal array unit, arranged on one side surface of the piezoelectric electret; an insulating layer, arranged in an area of the piezoelectric electret surface not covered by the signal array unit; a signal wire, arranged on the insulating layer, the signal wire being connected to the signal array unit; a ground layer and a ground wire, arranged on one side surface of the piezoelectric electret away from the signal array unit.

[0043] Through the above method, the present application can reduce the restrictions of the number and size of sensing units on the size of the piezoelectric sensor, and reduce the impact of the number and size of sensing units on the detection accuracy, and further improve the precision and accuracy of the sensing signal by increasing the density of the array units in the sensor.

[0044] The present application is described in detail below with reference to the accompanying drawings and implementation methods.

[0045] See also Figure 1 , Figure 1 FIG. 1 is a flow chart of an embodiment of a method for preparing a piezoelectric sensor of the present application. Figure 1 As shown, in this embodiment, the method includes:

[0046] S11: providing a piezoelectric electret.

[0047] In this embodiment, the piezoelectric electret is a complete and non-discrete integral film.

[0048] S12: Arrange a signal array unit on one side surface of the piezoelectric electret.

[0049] S13: providing an insulating layer in the area of the surface of the piezoelectric electret not covered by the signal array unit.

[0050] S14: fabricating signal conductors on the insulating layer and connecting the signal conductors to the signal array units.

[0051] In this embodiment, the signal wires are fabricated on the insulating layer, which can prevent the signal wires from being affected by the piezoelectric electret, so that the signal wires are only connected to the signal array unit, and the piezoelectric effect detected by the signal array unit is transmitted to the outside.

[0052] S15: Arrange a ground layer and a ground wire on a surface of the piezoelectric electret that is away from the signal array unit to obtain a piezoelectric sensor.

[0053] Different from the existing technology, in this embodiment, an array sensor is prepared on a complete and non-discrete piezoelectric electret film, which will not destroy the integrity of the piezoelectric electret and the flexibility of the sensor array will not be affected; at the same time, signal array units can also be prepared according to the size of the piezoelectric electret film, which will not be limited by the size of the sensing unit and can increase the density of the array units in the sensor; and since the signal wires are directly arranged on the insulating layer, the problems of installation and signal transmission between multiple wires are solved, which can improve the precision and accuracy of the sensing signal.

[0054] See further Figure 2 , Figure 2 yes Figure 1 Step S11 in the sub-flow chart of a preferred embodiment. Figure 2 As shown, in this embodiment, the method includes:

[0055] S21: preparing a polymer film and treating the polymer film so that the polymer film has a microporous structure.

[0056] In this embodiment, the polymer film is a high molecular polymer with excellent dielectric properties.

[0057] The polymer material includes at least one of polypropylene (PP), fluorinated ethylene propylene copolymer (FEP), and polytetrafluoroethylene (PTFE).

[0058] In other embodiments, the polymer material is other high molecular polymers with excellent dielectric properties, such as polychlorotrifluoroethylene (PCTFE), polyethylene terephthalate (PET), and polyethylene (PE), etc., which is not limited in this application.

[0059] In this embodiment, the polymer film may be provided with a porous structure by a swelling method, a template method, and an etching method, which is not limited in this application.

[0060] S22: performing polarization treatment on the polymer film having the microporous structure so that two opposite walls of the microporous structure have space charges of opposite polarities.

[0061] In this embodiment, the polymer film having a microporous structure can be polarized by corona poling and / or electron beam irradiation polarization so that the two opposite walls of the microporous structure have space charges of opposite polarities to form a piezoelectric electret. This application does not limit the specific polarization treatment method.

[0062] In this embodiment, a piezoelectric electret that has undergone a period of rapid charge decay is selected for use in fabricating the sensor.

[0063] Specifically, the piezoelectric electret obtained by polarization treatment will have a period of rapid charge decay. During the period of rapid charge decay, the charge stored in the microporous structure in the piezoelectric electret will decrease sharply. After the period of rapid charge decay, the charge decay trend on the surface of the microporous structure gradually slows down, and the charge decay amount becomes smaller and smaller. Finally, the charge value on the surface of the piezoelectric electret stabilizes within a certain range.

[0064] Furthermore, the duration of the rapid charge decay period is related to the properties of the polymer material, polarization conditions, etc. The stable range of piezoelectric electrets made of different materials is different. By measuring the surface potential of the piezoelectric electret, a piezoelectric electret with a stable charge value can be obtained.

[0065] In an optional embodiment, the surface potential of the electret may be measured by an electrostatic induction method, a capacitance probe method, a dynamic capacitance method, and a compensation method, which is not limited in this application.

[0066] See also Figure 3 , Figure 3 yes Figure 1 Step S12 in the sub-flow chart of a preferred embodiment. Figure 3 As shown, in this embodiment, the method includes:

[0067] S31: preparing a signal layer mask based on the set parameters of the signal array unit.

[0068] In this embodiment, the setting parameters of the signal array unit include the number and size of the signal sensing units required by the piezoelectric sensor and the spacing between adjacent signal sensing units.

[0069] The parameters for the signal array units can be determined based on the actual application scenario. For example, when the piezoelectric electret film is small, the size of the signal sensing units in a high-density array sensor can be set to a few millimeters, and the spacing between adjacent signal sensing units can also be set to a few millimeters. When the piezoelectric electret film is large, the size of the signal sensing units in a high-density array sensor can be set to tens of centimeters, and the spacing between adjacent signal sensing units can be set to a few centimeters.

[0070] In this embodiment, the setting parameters of the signal array unit are first set according to the number of signal units required by the piezoelectric sensor array and the size of the piezoelectric electret, and then the signal layer mask is prepared based on the setting parameters of the signal array unit.

[0071] S32: placing a signal layer mask plate on one side surface of the piezoelectric electret, and controlling metal particles to be deposited on the surface of the piezoelectric electret to form a signal array unit.

[0072] Specifically, see Figure 4a and Figure 4b , Figure 4a and Figure 4b This is a schematic diagram of the structure of the signal array unit of this application at various stages of preparation. Figure 4a It is a cross-sectional view and a top view of the coating process in step S32. Figure 4b It is a cross-sectional view and a top view after the coating process is completed in step S32.

[0073] like Figure 4a as well as Figure 4bAs shown, in this embodiment, after determining the setting parameters such as the number and size of the signal sensing units required in the signal array unit 31 and the spacing between adjacent signal sensing units according to the size of the piezoelectric electret 1, the signal layer mask plate 2 is prepared based on the setting parameters of the signal array unit 31, and the signal layer mask plate 2 is placed on one side surface of the piezoelectric electret 1, and the metal particles 30 are controlled to be deposited on the surface of the piezoelectric electret 1 to form the signal array unit 31 in the area not covered by the signal layer mask plate 2.

[0074] In this embodiment, the signal array unit 31 is a plurality of metal electrodes, that is, each metal electrode is a signal sensing unit.

[0075] In this embodiment, the metal electrodes are spaced apart from each other and arranged in a regular pattern.

[0076] In this embodiment, the metal particles 30 are metals with good electrical conductivity, such as aluminum, gold, silver, and alloys, which are not limited in this application.

[0077] In this embodiment, the metal particles 30 may be controlled to be deposited on the piezoelectric electret 1 by a coating method such as magnetron sputtering and / or chemical vapor deposition, which is not limited in this application.

[0078] See also Figure 5 , Figure 5 yes Figure 1 Step S13 in the sub-flow chart of a preferred embodiment. Figure 5 As shown, in this embodiment, the method includes:

[0079] S51: preparing a signal layer cover plate based on the set parameters of the signal array unit.

[0080] In this embodiment, the signal layer cover plate is used to cover the prepared signal array unit.

[0081] S52: After the signal array unit is covered by a signal layer cover plate, high molecular polymer particles are controlled to be deposited on the surface of the piezoelectric electret to form an insulating layer.

[0082] In this embodiment, before preparing the insulating layer, a signal layer cover plate of corresponding size is covered on the signal array unit to prevent polymer particles from being deposited on the surface of the signal array unit during the formation of the insulating layer, thereby affecting the conductive performance of the signal array unit.

[0083] Specifically, see Figure 6a and Figure 6b , Figure 6a and Figure 6b This is a schematic diagram of the structure of the insulating layer of the present application at various stages of preparation. Figure 6aIt is a cross-sectional view and a top view of the coating process in step S52. Figure 6b It is a cross-sectional view and a top view after the coating process is completed in step S52.

[0084] like Figure 6a as well as Figure 6b As shown, in this embodiment, a signal layer cover plate 4 is covered on the surface of the piezoelectric electret 1 where the signal array unit 31 is formed, so that the signal layer cover plate 4 just covers the signal array unit 31. Furthermore, high molecular polymer particles 50 are controlled to be deposited on the surface of the piezoelectric electret 1 to form an insulating layer 51 in the area not covered by the signal layer cover plate 4.

[0085] In this embodiment, the high molecular polymer particles 50 are polyparaxylene.

[0086] Parylene is highly resistant to almost all corrosive media and solvents. If the parylene layer is thin, its water permeability is also very low. Furthermore, parylene is very resistant to aging. Parylene, as the material for the insulating layer 51, can cover even the finest structures. Disposed on the surface of the piezoelectric electret 1, it ensures that the piezoelectric effect is transmitted only through the metal electrodes in the signal array unit 31.

[0087] In other embodiments, the high molecular polymer particles 50 may also be poly(monochloroparaxylene) and / or poly(dichloroparaxylene), etc., which is not limited in the present application.

[0088] In this embodiment, the high molecular polymer particles 50 may be controlled to be deposited on the piezoelectric electret 1 by a coating method such as magnetron sputtering and / or chemical vapor deposition.

[0089] See also Figure 7 , Figure 7 yes Figure 1 Step S14 in the sub-flow chart of a preferred embodiment. Figure 7 As shown, in this embodiment, the method includes:

[0090] S71: preparing a signal conductor mask plate connected to the signal array unit based on the signal array unit.

[0091] In this embodiment, the shape of the signal wire connected to each metal electrode in the signal array unit is first preset according to the signal array unit, and then a signal wire mask is prepared based on the shape of the signal wire and the connection method between the signal wire and the metal electrode.

[0092] In this embodiment, the output ports of the metal electrodes in the same row or column in the signal array unit are all set on the same side of the metal electrodes in the row or column, and the signal wires prepared subsequently are connected to the output ports of the metal electrodes through the output ports, so that the signal wires can be located on the same side of a row or column of metal electrodes.

[0093] S72: placing a signal conductor mask plate on the signal array unit and the insulating layer, and controlling metal particles to be deposited on the surfaces of the signal array unit and the insulating layer to form a signal conductor connected to the signal array unit.

[0094] In this embodiment, the metal particles deposited on the insulating layer are used to form signal wires, and the metal particles deposited on the signal array unit are used to form connections with the signal wires, so that the signal wires transmit the piezoelectric effect detected by the signal array unit to an external processor.

[0095] In this embodiment, the metal particles are metals with good electrical conductivity, such as aluminum, gold, silver, and alloys, etc., which are not limited in this application.

[0096] In this embodiment, the metal particles may be controlled to be deposited on the piezoelectric electret by a coating method such as magnetron sputtering and / or chemical vapor deposition, and this application does not limit this.

[0097] Specifically, see Figure 8a and Figure 8b , Figure 8a and Figure 8b This is a schematic diagram of the structure of the signal conductor after the coating process is completed in step S72. Figure 8a is a top view of the signal conductor after the coating process is completed in step S72. Figure 8b FIG. 5 is a cross-sectional view of the signal conductor after the plating process is completed in step S72 .

[0098] like Figure 8a and Figure 8b As shown, the metal particles 30 deposited on the insulating layer 51 are used to form the signal wires 32, and the metal particles 30 deposited on the signal array unit 31 are used to form connections with the signal wires 32. Since the signal wires 32 are formed on the insulating layer 51 and connected to the metal electrodes in the signal array unit 31, it can be ensured that the signal wires 32 are only used to transmit the electrical signals generated by the signal array unit 31.

[0099] Furthermore, since the output ports of the metal electrodes in the same row or column in the signal array unit 31 are all arranged on the same side of the metal electrodes in the row or column, and the signal wires 32 are connected to the output ports of the metal electrodes through the output ports, the signal wires 32 are all located on the same side of a row or column of metal electrodes. This arrangement is conducive to the connection of the signal wires 32 with the external flexible wires, and there will be no problem of a chaotic layout of the signal wires 32 affecting the transmission of electrical signals.

[0100] See also Figure 9 , Figure 9 yes Figure 1 Step S15 in the sub-flow chart of a preferred embodiment. Figure 9 As shown, in this embodiment, the method includes:

[0101] S91: Controlling metal particles to be deposited onto a surface of the piezoelectric electret that is away from the signal array unit to form a ground layer.

[0102] Since the grounding terminals of the signal array units can be connected to a common ground, the surface of the piezoelectric electret on one side away from the signal array units can be coated to form a ground layer.

[0103] In this embodiment, the position of the ground layer corresponds to the position of the signal array unit, so that the ground layer can cover all the metal electrodes, thereby improving the sensitivity and accuracy of the signal array unit detection.

[0104] In this embodiment, the metal particles are metals with good electrical conductivity, such as aluminum, gold, silver, and alloys, etc., which are not limited in this application.

[0105] In this embodiment, the metal particles may be controlled to be deposited onto the surface of the piezoelectric electret away from the signal array unit by a coating method such as magnetron sputtering and / or chemical vapor deposition, which is not limited in this application.

[0106] S92: Prepare a ground wire mask plate based on the connection method between the ground wire and the ground layer.

[0107] S93: placing a ground wire mask plate on the surface of the piezoelectric electret where the ground layer is located, controlling the metal particles to be deposited on the surface of the piezoelectric electret to form a ground wire connected to the ground layer, so as to obtain a piezoelectric sensor.

[0108] In this embodiment, by controlling the thicknesses of the piezoelectric electret 1 , the signal array unit 31 , the signal conductor 32 , the insulating layer 51 , and the ground layer 61 , the thickness of the piezoelectric sensor 60 can be controlled to be between 10 μm and 1000 μm.

[0109] Different from the prior art, the preparation method of the piezoelectric sensor provided by the present application will not destroy the integrity of the piezoelectric electret. The piezoelectric electret is a complete and non-discrete integral thin film, which will not be restricted by the size of the separated sensing unit, and its structure will not be destroyed. The signal wires are arranged on the insulating layer of the piezoelectric electret, which will not affect the installation of the piezoelectric sensor. At the same time, the signal wires are all arranged on the same side of the metal electrodes in the same column or row, which is conducive to the connection of the signal wires with the external flexible wires, and there will be no problem of chaotic signal wire layout affecting the transmission of electrical signals. Through the above methods, the present application can reduce the restrictions on the size of the piezoelectric sensor caused by the number and size of the sensing units, and reduce the impact of the number and size of the sensing units on the detection accuracy. By increasing the density of the array units in the sensor and cleverly setting the connection method of the signal wires, the precision and accuracy of the sensing signal can be further improved.

[0110] Correspondingly, the present application provides a piezoelectric sensor.

[0111] Specifically, see Figure 10 、 Figure 11 as well as Figure 12 , Figure 10 1 is a schematic cross-sectional view of an embodiment of a piezoelectric sensor of the present application; Figure 11 is a top view of an embodiment of a piezoelectric sensor of the present application; Figure 12 It is a bottom view of one embodiment of the piezoelectric sensor of the present application.

[0112] In this embodiment, the piezoelectric sensor 10 includes a piezoelectric electret 1 , a signal array unit 31 , an insulating layer 51 , a signal wire 32 , a ground layer 61 , and a ground wire 62 .

[0113] In this embodiment, the signal array unit 31 is disposed on one side of the piezoelectric electret 1; the insulating layer 51 is disposed on the surface of the piezoelectric electret 1 in an area not covered by the signal array unit 31; the signal conductor 32 is disposed on the insulating layer 51 and connected to the signal array unit 31. The ground layer 61 and the ground conductor 62 are disposed on the side of the piezoelectric electret 1 away from the signal array unit 31.

[0114] In this embodiment, the piezoelectric electret 1 is a complete, non-discrete polymer film having a microporous structure.

[0115] The polymer film is a high molecular polymer with excellent dielectric properties.

[0116] Specifically, the polymer material includes at least one of polypropylene (PP), fluorinated ethylene propylene copolymer (FEP), and polytetrafluoroethylene (PTFE).

[0117] In other embodiments, the polymer material is other high molecular polymers with excellent dielectric properties, such as polychlorotrifluoroethylene (PCTFE), polyethylene terephthalate (PET), and polyethylene (PE), etc., which is not limited in this application.

[0118] In this embodiment, the signal array unit 31 is located on the complete and non-discrete piezoelectric electret 1, so the integrity of the piezoelectric electret 1 will not be destroyed, the flexibility of the piezoelectric sensor 10 will not be affected, and the sensing signal generated by the signal array unit 31 has high precision and accuracy.

[0119] In this embodiment, the signal array unit 31 is a plurality of metal electrodes, which are spaced apart from each other and arranged in a regular pattern.

[0120] The material of the metal electrode includes metals with good electrical conductivity, such as aluminum, gold, silver, and alloys, which are not limited in this application.

[0121] In this embodiment, the metal electrode has a square structure.

[0122] In other embodiments, the metal electrode may also be a circular structure, which is not limited in this application.

[0123] In this embodiment, the number and size of the metal electrodes, as well as the spacing between adjacent metal electrodes, are related to the size of the piezoelectric electret 1. For example, when the piezoelectric electret 1 is small, the size of the metal electrodes can be several millimeters, and the spacing between adjacent metal electrodes can be several millimeters. When the piezoelectric electret 1 is large, the size of the metal electrodes can be tens of centimeters, and the spacing between adjacent metal electrodes can be several centimeters.

[0124] In this embodiment, the signal array unit 31 in the piezoelectric sensor 10 is not limited by the size of the metal electrodes. The size and number of the metal electrodes can vary according to the size of the piezoelectric electret 1. Since the density of the signal array unit 31 is not affected by the size of the discrete sensing units, the detection accuracy of the signal array unit 31 will not be affected.

[0125] In this embodiment, the insulating layer 51 is disposed adjacent to the metal electrodes in the signal array unit 31 .

[0126] The material of the insulating layer 51 includes a high molecular polymer with insulating properties.

[0127] In this embodiment, the material of the insulating layer 51 is parylene.

[0128] Parylene is highly resistant to almost all corrosive media and solvents. If the parylene layer is thin, its water permeability is also very low. Furthermore, parylene is very resistant to aging. Parylene, as the material for the insulating layer 51, can cover even the finest structures. Disposed on the surface of the piezoelectric electret 1, it ensures that the piezoelectric effect is transmitted only through the metal electrodes in the signal array unit 31.

[0129] In other embodiments, the material of the insulating layer 51 may also be poly(monochloroparaxylene) and / or poly(dichloroparaxylene), etc., which is not limited in the present application.

[0130] In this embodiment, the signal wires 32 of the metal electrodes in the same row or column are disposed on the same side of the metal electrodes in the row or column.

[0131] Specifically, the output ports of the metal electrodes in the same row in the signal array unit 31 are all on the same side, and the signal wires 32 are connected to the output ports of the metal electrodes. Therefore, the signal wires 32 connected to the metal electrodes in the same row are all arranged on the same side of the metal electrodes in the row.

[0132] Alternatively, the output ports of the metal electrodes in the same column in the signal array unit 31 are all on the same side, and the signal wires 32 are connected to the output ports of the metal electrodes. Therefore, the signal wires 32 connected to the metal electrodes in the same column are all arranged on the same side of the metal electrodes in the column. This application does not limit this.

[0133] Since the piezoelectric electret 1 in this embodiment is a complete, non-discrete film, and the signal array unit 31 and the signal wire 32 are both directly disposed on the piezoelectric electret 1, it is convenient to connect the signal wire 32 with the external flexible wire, and there will be no problem of a chaotic layout of the signal wire 32 affecting the transmission of electrical signals.

[0134] In this embodiment, the sum of the thicknesses of the signal wire 32 and the insulating layer 51 is no greater than the thickness of the signal array unit 31 , so that the signal wire 32 can be well connected to the signal array unit 31 .

[0135] In this embodiment, the position of the ground layer 61 corresponds to the position of the signal array unit 31 .

[0136] The area of the ground layer 61 is not less than the total area of the signal array unit 31 , so that the ground layer 61 can cover all metal electrodes in the signal array unit 31 , thereby improving the sensitivity and accuracy of detection of the signal array unit 31 .

[0137] In this embodiment, a ground wire 62 is provided on one side of the ground layer 61 for providing a reference signal so that the electrical signal transmitted externally by the piezoelectric sensor 10 has higher precision and accuracy.

[0138] In this embodiment, the thickness of the piezoelectric sensor 10 is 10 μm to 1000 μm.

[0139] Specifically, the thickness of the piezoelectric sensor 10 is related to the thickness of the piezoelectric electret 1 , the signal array unit 31 , the signal wire 32 , the insulating layer 51 , and the ground layer 61 .

[0140] In an optional embodiment, when the thickness of the piezoelectric sensor 10 is 10 μm, it can be applied to artificial skin.

[0141] In another optional embodiment, when the thickness of the piezoelectric sensor 10 is 800 μm, it can be applied to smart wearable devices.

[0142] Different from the prior art, the piezoelectric sensor provided by the present application is a complete and non-discrete integral thin film, so the integrity of the piezoelectric electret will not be destroyed, nor will it be restricted by the size of the separated sensing unit, and its structure will not be destroyed; and the signal wires are directly arranged on the insulating layer on the surface of the piezoelectric electret, so it will not affect the installation of the piezoelectric sensor. At the same time, since the signal wires are all arranged on one side of the same column or row of metal electrodes, it is convenient to connect the signal wires with the external flexible wires, and there will be no problem of chaotic signal wire layout affecting the transmission of electrical signals. The piezoelectric sensor provided by the present application has good flexibility and is not restricted by the number and size of sensing units. It can accommodate higher density signal array units, has high sensitivity to the detection of dynamic forces, and the sensing signals it generates have higher precision and accuracy.

[0143] The piezoelectric sensor provided in this application can be used for tactile and vibration signal detection in prosthetic hands, robots, and artificial skin, and can also be used as a sensor for force signal detection in other fields.

[0144] In a specific implementation scenario, the piezoelectric sensor includes a high-density and small-sized signal array unit. When the piezoelectric sensor is applied to vibration detection, the high-density signal array unit can detect a more accurate vibration position.

[0145] In another specific implementation scenario, the piezoelectric sensor includes a high-density and small-sized signal array unit. When the piezoelectric sensor is applied to artificial skin, the high-density signal array unit can accurately sense the stress changes in the external environment in real time, thereby achieving the purpose of simulating, restoring or even replacing the body's skin, and can be used in the treatment of burn patients.

[0146] The above description is only an implementation method of the present application and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the description and drawings of this application, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for preparing a piezoelectric sensor, characterized in that: include: providing a piezoelectric electret; A signal array unit is provided on one side surface of the piezoelectric electret; Providing an insulating layer on the surface of the piezoelectric electret in an area not covered by the signal array unit, comprising: preparing a signal layer cover plate based on set parameters of the signal array unit; after covering the signal array unit with the signal layer cover plate, controlling the deposition of polymer particles onto the surface of the piezoelectric electret to form the insulating layer; Fabricating a signal wire on the insulating layer and connecting the signal wire to the signal array unit; wherein the sum of the thickness of the signal wire and the insulating layer is less than or equal to the thickness of the signal array unit; A ground layer and a ground wire are provided on a surface of the piezoelectric electret at a side away from the signal array unit to obtain the piezoelectric sensor.

2. The method for preparing a piezoelectric sensor according to claim 1, wherein: The step of providing a signal array unit on one side surface of the piezoelectric electret specifically includes: preparing a signal layer mask based on the set parameters of the signal array unit; The signal layer mask is placed on one side surface of the piezoelectric electret, and metal particles are controlled to be deposited on the surface of the piezoelectric electret to form the signal array unit.

3. The method for preparing a piezoelectric sensor according to claim 2, wherein: The step of providing a signal wire on the insulating layer and connecting the signal wire to the signal array unit specifically includes: Prepare a signal conductor mask plate connected to the signal array unit based on the signal array unit; The signal conductor mask is placed on the signal array unit and the insulating layer, and the metal particles are controlled to be deposited on the surfaces of the signal array unit and the insulating layer to form the signal conductor connected to the signal array unit.

4. The method for preparing a piezoelectric sensor according to claim 3, wherein: The step of providing a ground layer and a ground wire on a surface of the piezoelectric electret away from the signal array unit to obtain the piezoelectric sensor specifically includes: Controlling the metal particles to be deposited on a surface of the piezoelectric electret away from the signal array unit to form the ground layer; wherein the position of the ground layer corresponds to the position of the signal array unit so that the ground layer covers the signal array unit; preparing a ground wire mask plate based on the connection method between the ground wire and the ground layer; The ground wire mask plate is placed on the surface of the piezoelectric electret where the ground layer is located, and metal particles are controlled to be deposited on the surface of the piezoelectric electret to form the ground wire connected to the ground layer, so as to obtain the piezoelectric sensor.

5. The method for preparing a piezoelectric sensor according to claim 4, wherein: The step of providing a piezoelectric electret specifically includes: preparing a polymer film, and treating the polymer film so that the polymer film has a microporous structure; The polymer film having the microporous structure is subjected to a polarization treatment so that two opposite walls of the microporous structure have space charges with opposite polarities.

6. The method for preparing a piezoelectric sensor according to claim 5, wherein: The polymer film is a high molecular polymer with excellent dielectric properties.

7. The method for preparing a piezoelectric sensor according to claim 5, wherein: The metal particles are metals with good electrical conductivity.

8. The method for preparing a piezoelectric sensor according to claim 5, wherein: The high molecular polymer particles are high molecular polymers with insulating properties.

9. A piezoelectric sensor, characterized in that: The piezoelectric sensor is made by the preparation method of the piezoelectric sensor according to any one of claims 1 to 8; The piezoelectric sensor comprises: piezoelectric electret; A signal array unit is provided on one side surface of the piezoelectric electret; an insulating layer, the insulating layer being disposed on a region of the surface of the piezoelectric electret that is not covered by the signal array unit; wherein the insulating layer is formed by depositing high molecular polymer particles; a signal wire, the signal wire being disposed on the insulating layer and connected to the signal array unit; wherein the sum of the thickness of the signal wire and the insulating layer is less than or equal to the thickness of the signal array unit; A ground layer and a ground wire are provided on a surface of the piezoelectric electret that is away from the signal array unit.

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