A piezoelectric composite material, a driver and a preparation method thereof

Abstract

The present invention provides a piezoelectric composite material, a driver and a preparation method thereof, relating to the technical field of piezoelectric composite material drivers. The piezoelectric composite material includes: a top interdigitated electrode layer, a piezoelectric fiber composite layer and a bottom interdigitated electrode layer which are sequentially arranged from top to bottom; the top interdigitated electrode layer, the piezoelectric fiber composite layer and the bottom interdigitated electrode layer are all in a parallelogram structure; a piezoelectric ceramic fiber array is embedded in the piezoelectric fiber composite layer; the piezoelectric ceramic fiber array is in a parallelogram structure. By arranging the parallelogram piezoelectric ceramic fiber array, the effective area of the driver can be increased, thereby improving the driving effect of the driver.

Description

Technical Field

[0001] The present invention relates to the technical field of piezoelectric composite actuators, and particularly to piezoelectric composites, actuators and their preparation methods. Background Art

[0002] Piezoelectric composites are a kind of composite materials with piezoelectric effect obtained by combining piezoelectric ceramic phase materials and polymer phase materials in a certain connected manner; in addition to retaining the advantages of large driving deformation, fast response speed, wide frequency response range and good stability of traditional piezoelectric ceramics, they also overcome the disadvantages of large brittleness of ceramics and great difficulty in integrating with curved surface structures. The properties of piezoelectric composites are mainly determined by the connected manner of each phase. At present, the piezoelectric composite layers in common piezoelectric fiber composite actuators are composed of piezoelectric ceramic fibers with rectangular cross-sections and polymer matrices compounded in a 1-3 or 2-2 connection mode, and the upper and lower two-layer interdigital electrode layers are used to encapsulate the piezoelectric composite layer (note: in the connection mode, the first number represents the self-connection mode of the piezoelectric phase, and the second number represents the self-connection mode of the polymer phase: 2-2 means that the piezoelectric ceramic phase and the polymer phase are self-connected in a two-dimensional plane and extend in their respective planes; 1-3 means that the piezoelectric ceramic phase is one-dimensionally self-connected, while the polymer phase is self-connected in three-dimensional space). The use of fibrous ceramic phases increases the compatibility of the composite materials, making them applicable to large-plane or non-plane situations. At the same time, the use of interdigital electrodes introduces a polarization direction parallel to the fibers and an electric field direction, making full use of the advantage of high longitudinal piezoelectric constant d33 of piezoelectric ceramics, improving the output deformation ability of the actuator, and further strengthening the anisotropic characteristics of the driving device. Therefore, piezoelectric fiber composites have been widely used in the fields of driving deformation control, vibration and noise reduction, structural health monitoring and energy harvesting.

[0003] Currently, common piezoelectric fiber composites and actuators are in a rectangular configuration: when processing piezoelectric ceramic fibers, the mechanical cutting direction is parallel to the long side of the final formed actuator appearance, obtaining a rectangular configuration of piezoelectric ceramic fiber arrays; the positive and negative electrode buses of the interdigital electrode layers on the upper and lower surfaces of the actuator are arranged on both sides of the piezoelectric fiber array, and the positive and negative electrode branches extending from the buses are perpendicular to the piezoelectric fibers and are alternately arranged at equal intervals along the fiber length direction. When an external excitation voltage is applied, the driving device will be in its long side direction (d 33 mode) and width direction (d 31Output deformation in the (mode). Adhering it to the surface of the engineering structure can drive the telescopic or bending deformation of the structure, and the excitation voltage signal is used to achieve the purpose of active control of the engineering structure. However, in practical applications, the appearance configuration of traditional rectangular piezoelectric fiber composite actuators greatly limits the realization of device driving. Taking the torsional requirement of a common driving cantilever beam structure as an example: when using a rectangular piezoelectric fiber composite actuator to drive the structural deformation, if the laying direction of the actuator (i.e., the piezoelectric fiber direction) is parallel or perpendicular to the beam axis, the cantilever beam will undergo pure bending deformation; if the laying direction of the actuator forms an angle of ±45° with the beam axis, the cantilever beam will produce effective torsional deformation. However, in practical applications, the size of the engineering structure is fixed. When integrating the rectangular actuator with the structure, the effective area of the actuator is limited and cannot fully cover the structure, and the space utilization rate of the cantilever beam structure surface is low, greatly weakening the final torsional driving effect of the device. Summary of the Invention

[0004] The purpose of the present invention is to provide a piezoelectric composite material, an actuator and a preparation method thereof. The piezoelectric composite material is applied to the actuator. By setting a parallelogram piezoelectric ceramic fiber array, the effective area of the actuator can be increased, thereby improving the driving effect of the actuator.

[0005] To achieve the above purpose, the present invention provides the following solutions:

[0006] A piezoelectric composite material, comprising: a top interdigitated electrode layer, a piezoelectric fiber composite layer and a bottom interdigitated electrode layer arranged in sequence from top to bottom;

[0007] The top interdigitated electrode layer, the piezoelectric fiber composite layer and the bottom interdigitated electrode layer are all of parallelogram structure;

[0008] A piezoelectric ceramic fiber array is embedded in the piezoelectric fiber composite layer; the piezoelectric ceramic fiber array is of parallelogram structure.

[0009] Optionally, a first polymer colloid layer is provided between the top interdigitated electrode layer and the piezoelectric fiber composite layer;

[0010] A second polymer colloid layer is provided between the piezoelectric fiber composite layer and the bottom interdigitated electrode layer.

[0011] Optionally, the piezoelectric ceramic fiber array includes a plurality of piezoelectric ceramic blocks;

[0012] The shapes and sizes of the plurality of piezoelectric ceramic blocks are the same; the plurality of piezoelectric ceramic blocks are all of parallelogram structure;

[0013] The bottom sides of the plurality of piezoelectric ceramic blocks are in the same pointing direction; and the distance between any two adjacent piezoelectric ceramic blocks is equal.

[0014] Optionally, the upper interleaved finger electrode layer includes: a substrate, a positive electrode, and a negative electrode;

[0015] The positive electrode and the negative electrode are arranged in an interleaved manner on the same side surface of the substrate;

[0016] The substrate has a parallelogram structure.

[0017] Optionally, the positive electrode includes a first main electrode line, a second main electrode line, and a plurality of first branch electrode lines;

[0018] The first main electrode line is arranged along the bottom edge of the substrate;

[0019] The second main electrode line is arranged along the first adjacent side of the bottom edge of the substrate; the first adjacent side is the adjacent side with an obtuse angle with the bottom edge of the substrate;

[0020] One end of the first main electrode line and one end of the second main electrode line intersect at the obtuse vertex on the bottom edge of the substrate;

[0021] The length of the first main electrode line is less than the length of the bottom edge of the substrate;

[0022] The length of the second main electrode line is less than the length of the first adjacent side;

[0023] A plurality of the first branch electrode lines are arranged in parallel on the substrate;

[0024] One ends of a plurality of the first branch electrode lines are all connected to the first main electrode line or the second main electrode line; a plurality of the first branch electrode lines are all perpendicular to the first adjacent side;

[0025] The distance between any two adjacent first branch electrode lines is equal.

[0026] Optionally, the negative electrode includes a third main electrode line, a fourth main electrode line, and a plurality of second branch electrode lines;

[0027] The third main electrode line is arranged along the opposite side of the bottom edge of the substrate;

[0028] The fourth main electrode line is arranged along the second adjacent side of the bottom edge of the substrate; the second adjacent side is the adjacent side with an acute angle with the bottom edge of the substrate;

[0029] One end of the third main electrode line and one end of the fourth main electrode line intersect at the obtuse vertex on the second adjacent side of the substrate;

[0030] The length of the third main electrode line is equal to the length of the first main electrode line;

[0031] The length of the fourth main electrode line is equal to the length of the second main electrode line;

[0032] Multiple second branch electrode lines are arranged in parallel on the substrate;

[0033] One ends of multiple second branch electrode lines are all connected to the third main electrode line or the fourth main electrode line; multiple second branch electrode lines are all perpendicular to the first adjacent side;

[0034] The distance between any two adjacent second branch electrode lines is equal.

[0035] Optionally, the first branch electrode lines and the second branch electrode lines are arranged at intervals;

[0036] The first branch electrode lines and the second branch electrode lines are only connected to one main electrode line; the main electrode lines include: the first main electrode line, the second main electrode line, the third main electrode line, and the fourth main electrode line.

[0037] A driver, the driver applying the piezoelectric composite material.

[0038] A preparation method, the preparation method being used to prepare the driver, the method including:

[0039] Paste the rectangular piezoelectric ceramic thin sheet to be cut on the cutting tape;

[0040] Set the direction of the bottom edge of the rectangular piezoelectric ceramic thin sheet as the cutting step direction, set the direction at a preset angle to the cutting step direction as the cutting direction, and use a cutting machine to cut the rectangular piezoelectric ceramic thin sheet to obtain a plurality of piezoelectric ceramic blocks as a piezoelectric ceramic fiber array;

[0041] Pour the melted polymer colloid into the gaps between the plurality of piezoelectric ceramic blocks and cure and form it using a hot press, and tear off the cutting tape to obtain a piezoelectric fiber composite layer;

[0042] Use printed circuit technology to etch a positive electrode and a negative electrode on two parallelogram substrates respectively to obtain an upper interdigitated electrode layer and a lower interdigitated electrode layer;

[0043] Bond the upper interdigitated electrode layer to the upper surface of the piezoelectric fiber composite layer using polymer colloid, bond the lower interdigitated electrode layer to the lower surface of the piezoelectric fiber composite layer using polymer colloid, and then perform a curing treatment to obtain a piezoelectric composite material;

[0044] Weld wires on the upper interdigitated electrode layer and the lower interdigitated electrode layer respectively, and apply a DC voltage to the piezoelectric composite material through the wires for polarization treatment to obtain a driver.

[0045] Optionally, the range of the preset included angle is 30°-60°.

[0046] According to the specific embodiments provided by the present invention, the following technical effects are disclosed by the present invention:

[0047] The present invention provides a piezoelectric composite material, a driver and a preparation method thereof. The piezoelectric composite material includes: a top interdigitated electrode layer, a piezoelectric fiber composite layer and a bottom interdigitated electrode layer which are sequentially arranged from top to bottom; the top interdigitated electrode layer, the piezoelectric fiber composite layer and the bottom interdigitated electrode layer are all parallelogram structures; a piezoelectric ceramic fiber array is embedded in the piezoelectric fiber composite layer; the piezoelectric ceramic fiber array is a parallelogram structure. By providing the parallelogram piezoelectric ceramic fiber array, the effective area of the driver can be increased, and thus the driving effect of the driver can be improved. Description of the Drawings

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0049] Figure 1 It is a schematic diagram of the structure of a piezoelectric composite material in Embodiment 1 of the present invention;

[0050] Figure 2 It is a schematic diagram of the structure of the bottom interdigitated electrode layer in Embodiment 1 of the present invention;

[0051] Figure 3 It is a flowchart of the preparation method in Embodiment 3 of the present invention;

[0052] Label description: 1 - interdigitated electrode layer, 2 - polymer colloid layer, 3 - piezoelectric fiber composite layer, 4 - main electrode wire, 5 - substrate, 6 - rectangular piezoelectric ceramic sheet, 7 - cutting tape, 8 - piezoelectric ceramic fiber array, 9 - polymer colloid in the gap of the piezoelectric ceramic block. Detailed Embodiments

[0053] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the protection scope of the present invention.

[0054] The object of the present invention is to provide a piezoelectric composite material, a driver and a preparation method thereof. The piezoelectric composite material is applied to the driver. By arranging a parallelogram piezoelectric ceramic fiber array, the effective area of the driver can be increased, and thus the driving effect of the driver can be improved.

[0055] In order to make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0056] Embodiment 1

[0057] As Figure 1 shown, this embodiment provides a piezoelectric composite material, including: an interdigital electrode layer 1 (including an upper interdigital electrode layer and a lower interdigital electrode layer) and a piezoelectric fiber composite layer 3 arranged in sequence from top to bottom; the upper interdigital electrode layer, the piezoelectric fiber composite layer and the lower interdigital electrode layer are all in a parallelogram structure; a piezoelectric ceramic fiber array 8 is embedded in the piezoelectric fiber composite layer; the piezoelectric ceramic fiber array is in a parallelogram structure. A first polymer colloid layer is arranged between the upper interdigital electrode layer and the piezoelectric fiber composite layer; a second polymer colloid layer is arranged between the piezoelectric fiber composite layer and the lower interdigital electrode layer. The polymer colloid layer 2 includes the first polymer colloid layer and the second polymer colloid layer.

[0058] Specifically, the piezoelectric ceramic fiber array includes a plurality of piezoelectric ceramic blocks; the shapes and sizes of the plurality of piezoelectric ceramic blocks are the same; the plurality of piezoelectric ceramic blocks are all in a parallelogram structure; the bottom edges of the plurality of piezoelectric ceramic blocks point in the same direction; and the distance between any two adjacent piezoelectric ceramic blocks is equal.

[0059] In addition, the upper interdigital electrode layer includes: a substrate 5, a positive electrode and a negative electrode; the positive electrode and the negative electrode are arranged in an interdigital shape on the same side surface of the substrate; the substrate is in a parallelogram structure. The structures of the upper interdigital electrode layer and the lower interdigital electrode layer are the same; as Figure 2 shown, the structures of the lower interdigital electrode layer and the upper interdigital electrode layer also include: a substrate 5, a positive electrode and a negative electrode; the positive electrode and the negative electrode are arranged in an interdigital shape on the same side surface of the substrate; the substrate is in a parallelogram structure; the difference is that in the upper interdigital electrode layer, the positive electrode and the negative electrode are arranged in an interdigital shape on the lower surface of the substrate; in the lower interdigital electrode layer, the positive electrode and the negative electrode are arranged in an interdigital shape on the upper surface of the substrate.

[0060] Among them, the positive electrode includes a first main electrode line, a second main electrode line, and a plurality of first branch electrode lines; the first main electrode line is disposed along the bottom edge of the substrate; the second main electrode line is disposed along a first adjacent edge of the bottom edge of the substrate; the first adjacent edge is an adjacent edge with an obtuse angle with respect to the bottom edge of the substrate; one end of the first main electrode line and one end of the second main electrode line intersect at an obtuse vertex on the bottom edge of the substrate; the length of the first main electrode line is less than the length of the bottom edge of the substrate; the length of the second main electrode line is less than the length of the first adjacent edge; the plurality of first branch electrode lines are arranged in parallel on the substrate; one end of each of the plurality of first branch electrode lines is connected to the first main electrode line or the second main electrode line; the plurality of first branch electrode lines are all perpendicular to the first adjacent edge; the distance between any two adjacent first branch electrode lines is equal.

[0061] The negative electrode includes a third main electrode line, a fourth main electrode line, and a plurality of second branch electrode lines; the third main electrode line is disposed along the opposite side of the bottom edge of the substrate; the fourth main electrode line is disposed along a second adjacent edge of the bottom edge of the substrate; the second adjacent edge is an adjacent edge with an acute angle with respect to the bottom edge of the substrate; one end of the third main electrode line and one end of the fourth main electrode line intersect at an obtuse vertex on the second adjacent edge of the substrate; the length of the third main electrode line is equal to the length of the first main electrode line; the length of the fourth main electrode line is equal to the length of the second main electrode line; the plurality of second branch electrode lines are arranged in parallel on the substrate; one end of each of the plurality of second branch electrode lines is connected to the third main electrode line or the fourth main electrode line; the plurality of second branch electrode lines are all perpendicular to the first adjacent edge; the distance between any two adjacent second branch electrode lines is equal.

[0062] Among them, the first branch electrode lines and the second branch electrode lines are arranged at intervals; the first branch electrode lines and the second branch electrode lines are only connected to one main electrode line; the main electrode lines include: a first main electrode line, a second main electrode line, a third main electrode line, and a fourth main electrode line.

[0063] Embodiment 2

[0064] This embodiment provides a driver, and the driver applies a piezoelectric composite material as described in Embodiment 1.

[0065] Embodiment 3

[0066] As Figure 3 shown, this embodiment provides a preparation method, and the preparation method is used to prepare the driver described in Embodiment 2. The method includes:

[0067] Step 1: Paste the rectangular piezoelectric ceramic thin sheet 6 to be cut onto the cutting tape 7; wipe the rectangular piezoelectric ceramic thin sheet to be cut with anhydrous ethanol before pasting; paste the rectangular piezoelectric ceramic thin sheet at the center of the cutting tape, tighten the cutting tape and fix it to the cutting machine, and mark the long side direction of the piezoelectric thin sheet as the first direction. The piezoelectric ceramic thin sheet material is PZT, PMN-PT, KNN or BT series piezoelectric ceramics, and the thickness of the thin sheet can be selected in the range of 0.1 mm - 0.5 mm. The cutting tape is a UV cutting protective film.

[0068] Step 2: Set the direction of the bottom edge of the rectangular piezoelectric ceramic thin sheet as the cutting step direction, set the direction at a preset angle to the cutting step direction as the cutting direction, and use the cutting machine to cut the rectangular piezoelectric ceramic thin sheet to obtain multiple piezoelectric ceramic blocks as the piezoelectric ceramic fiber array;

[0069] Among them, the range of the preset angle is 30° - 60°. Mechanically cut the piezoelectric ceramic thin sheet, and the cutting direction forms a specific required angle with the first direction, denoted as the second direction of the piezoelectric thin sheet. Take the first direction as the cutting step direction, and the cutting step distance is fixed; after cutting, take out the residual waste of the ceramic sheet to obtain a parallelogram piezoelectric ceramic fiber array.

[0070] The width of the fibers (piezoelectric ceramic blocks) in the piezoelectric ceramic fiber array can be continuously adjusted in the range of 0.5 mm - 2 mm by changing the cutting step distance, and the fiber gap can be continuously adjusted in the range of 0.1 mm - 0.25 mm by using cutting blades of different thicknesses.

[0071] Step 3: Pour the melted polymer colloid into the gaps between multiple piezoelectric ceramic blocks and use a hot press to cure and form. After tearing off the cutting tape, a piezoelectric fiber composite layer is obtained; the polymer colloid 9 in the gaps between the piezoelectric ceramic blocks is as Figure 3 shown.

[0072] Pour the prepared polymer colloid into the fiber gaps of the parallelogram piezoelectric array, and place it horizontally at the center of the hot press workbench. Set the workbench pressure and temperature, keep warm and press for a period of time, and then the parallelogram piezoelectric fiber composite material is cured and formed. Take out the formed piezoelectric fiber composite material, tear off the cutting tape on the lower surface, and wipe the upper and lower surfaces of the material with anhydrous ethanol for standby.

[0073] Here, the polymer colloid is selected as thermosetting epoxy resin. The setting range of the curing pressure of the piezoelectric composite material is 0.1 MPa - 2 MPa, the setting range of the curing temperature is 80°C - 150°C, and the duration of heat preservation and pressure holding is 120 min - 240 min.

[0074] Step 4: Using printed circuit technology, positive and negative electrodes are etched on two parallelogram substrates to obtain an upper interdigitated electrode layer and a lower interdigitated electrode layer; using printed circuit technology, with polyimide as the base material, the interdigital circuit line patterns of the upper and lower surface electrodes printed on one side are etched with tinned copper: both the positive and negative electrode buses are composed of two electrode lines parallel to the first and second directions, and the buses enclose an electrode coverage area in a parallelogram configuration; the positive and negative branch electrode lines extending from the positive and negative buses are perpendicular to the second direction; the size of the electrode effective area formed by the interdigital electrode lines is the same as the size of the parallelogram piezoelectric fiber composite prepared above; the circuit patterns of the upper and lower surface electrodes are mirror-symmetrical. The width of the etched electrode line is continuously adjustable within the range of 0.1 - 1.0 mm, and the distance between adjacent opposite-sex electrode branches is continuously adjustable within the range of 0.5 mm - 2.0 mm or more.

[0075] Step 5: The upper interdigitated electrode layer is bonded to the upper surface of the piezoelectric fiber composite layer using a polymer colloid, and the lower interdigitated electrode layer is bonded to the lower surface of the piezoelectric fiber composite layer using a polymer colloid, and then curing treatment is carried out to obtain the piezoelectric composite material as described in Example 1.

[0076] Wipe the surfaces of the upper and lower interdigital electrode layers prepared above with anhydrous ethanol; evenly apply the polymer colloid on the upper and lower surfaces of the parallelogram piezoelectric fiber composite prepared above, and attach the upper and lower interdigital electrodes to the upper and lower surfaces of the material respectively; the electrode layer and the piezoelectric composite layer are closely fitted without bubbles; the effective area of the electrode layer coincides with the parallelogram piezoelectric composite layer, and the same-sex electrode lines in the upper and lower interdigital electrode layers are strictly aligned. Place the obtained laminated structure of lower interdigital electrode layer - piezoelectric fiber composite layer - upper interdigital electrode layer at the center of the hot press workbench, set the pressure and temperature of the workbench, and after maintaining the temperature and pressure for a period of time, the colloid between the electrode layer and the piezoelectric composite layer is completely cured; take it out and trim the edges.

[0077] The polymer colloid selected is a thermosetting epoxy resin, the setting range of the colloid curing pressure is 0.5 MPa - 5 MPa, the setting range of the curing temperature is 80 °C - 150 °C, and the setting range of the holding time for maintaining the temperature and pressure is 120 min - 240 min.

[0078] Step 6: Wires are welded to the upper interdigitated electrode layer and the lower interdigitated electrode layer respectively, and a DC voltage is applied to the piezoelectric composite material through the wires for polarization treatment to obtain the actuator as described in Example 2.

[0079] At room temperature, after applying a DC voltage to the electrodes for polarization treatment for a period of time, the preparation of the device is completed. The DC polarization voltage is set in the range of 1.5 kV - 6.0 kV according to the distance between adjacent opposite-sex electrode branches, and the polarization time is 20 min - 60 min.

[0080] The present invention will be specifically described below by taking the preparation of a parallelogram piezoelectric fiber composite material and a driver with an effective area length of 50 mm, a height of 30 mm, a thickness of 0.25 mm, and a vertex angle of 45° as an example:

[0081] Step 1: Wipe the unpolarized PZT-5H rectangular piezoelectric ceramic sheet with a length of 80 mm, a width of 30 mm, and a thickness of 0.25 mm using anhydrous ethanol; paste the piezoelectric ceramic sheet on a cutting tape with a length of 200 mm, a width of 150 mm, and a thickness of 0.1 mm; the rectangular piezoelectric sheet should be as close as possible to the center of the cutting tape, and ensure that the piezoelectric sheet is closely attached to the cutting tape without air bubbles.

[0082] Step 2: Tighten the cutting tape with the piezoelectric sheet attached and assemble it onto a dicing saw. Take the direction parallel to the long side of the piezoelectric ceramic sheet as the first direction, and set the direction at an angle of 45° to the first direction as the second direction of the sheet. Set the cutting parameters, use a cutting blade with a thickness of 0.1 mm, take the first direction as the cutting step direction, the second direction as the cutting direction, the cutting step spacing is fixed at 0.4 mm, the cutting remaining thickness is 0.08 mm, and the total number of cutting blades is 101. After 101 cuts, remove the residual parts on both sides of the piezoelectric ceramic sheet to obtain a parallelogram piezoelectric array composed of 100 piezoelectric ceramic fibers parallel to the second direction. Wipe the surface of the ceramic fiber array with anhydrous ethanol and set it aside for later use.

[0083] Step 3: Weigh 50 g of E-44 epoxy resin, 10 g of low molecular weight 650 polyamide resin curing agent, and 10 g of dibutyl phthalate toughening agent respectively using a balance. Stir well with a glass rod and then evacuate the air bubbles to complete the preparation of the polymer matrix. Use the polymer matrix to pour and fill the gaps of the above parallelogram piezoelectric ceramic fiber array, and place it at the center of the hot press workbench. Set the workbench pressure to 0.5 MPa and the temperature to 100 °C. After heat preservation and pressure holding for 180 min, the polymer matrix is completely cured. Take out the shaped parallelogram piezoelectric fiber composite material, tear off the cutting tape on the lower surface, wipe the upper and lower surfaces of the piezoelectric composite layer with anhydrous ethanol, and set it aside for later use.

[0084] Step 4: Using printed circuit board technology, etch electrode lines on the surface of the polyimide insulating layer with tinned copper to prepare a parallelogram flexible interdigital electrode on the upper surface. The electrode pattern is as shown in Figure 2As shown. The etched electrode line width is 0.2mm, the spacing between adjacent anisotropic electrode branches is 0.5mm, and the positive and negative branch electrodes are perpendicular to the second direction of the piezoelectric sheet, that is, perpendicular to the piezoelectric fibers in the piezoelectric composite layer. The interdigitated electrode pattern on the lower surface is mirror-symmetrical to the interdigitated electrode pattern on the upper surface, and the shape and size of the electrode effective area are consistent with the piezoelectric fiber composite material prepared above. Use anhydrous ethanol to wipe the prepared parallelogram upper and lower interdigitated electrode layers and set them aside for use.

[0085] Step 5: Use a balance to weigh 10g of E-44 epoxy resin, 2g of low molecular weight 650 polyamide resin curing agent, and 2g of dibutyl ester toughening agent, stir with a glass rod to mix thoroughly, and then evacuate the air bubbles to complete the preparation of the polymer colloid. Apply the colloid evenly to the upper and lower surfaces of the parallelogram piezoelectric fiber composite material prepared above. Apply the prepared upper and lower interdigitated electrodes to the upper and lower surfaces of the piezoelectric composite layer respectively. The pasting operation process ensures that the electrode layer and the piezoelectric composite layer are tightly attached without bubbles; the effective area of ​​the electrode layer overlaps with the parallelogram piezoelectric composite layer; and the same-sex electrode lines in the upper and lower interdigitated electrode layers are strictly aligned.

[0086] Step 6: Place the laminated structure of lower interdigital electrode layer-piezoelectric fiber composite layer-upper interdigital electrode layer obtained in step 5 in the middle of the hot press workbench, set the workbench pressure to 2.5MPa, the temperature to 100℃, and keep the temperature and pressure for 180min until the colloid between the electrode layer and the piezoelectric composite layer is completely solidified. Take out the formed parallelogram piezoelectric fiber composite actuator and trim it.

[0087] Step 7: Weld the positive and negative electrode wires for the finalized actuator in step 6, apply a DC polarization voltage of 1.5 kV at room temperature, and polarize for 30 minutes to complete the preparation of the parallelogram-shaped piezoelectric fiber composite actuator.

[0088] The present invention provides a piezoelectric composite material, a driver and a preparation method thereof, which are simple to operate, have low equipment requirements and are easy to implement. The obtained piezoelectric drive device has a novel configuration, which overcomes the problem of limited effective area when the traditional rectangular configuration piezoelectric fiber composite driver drives the structure torsional deformation, and can effectively meet the actual structural torsional deformation requirements. In addition, the driver size is precisely controllable, and the cutting direction of the piezoelectric ceramic sheet can be adjusted according to practical needs to obtain a piezoelectric fiber array arranged in a specific direction, and a special parallelogram configuration piezoelectric composite layer is obtained by casting a polymer matrix. At the same time, the volume fraction of the piezoelectric phase and the effective area in the obtained parallelogram piezoelectric composite layer can be effectively controlled by adjusting the cutting step and the size of the piezoelectric fiber array, which can adapt to different needs in actual application requirements.

[0089] In addition, in order to achieve effective polarization and actuation of piezoelectric fibers, a matching parallelogram interdigitated electrode layer is designed for the parallelogram configuration piezoelectric fiber composite. The positive and negative branch electrode lines in the upper and lower electrode layers are perpendicular to the direction of the piezoelectric fibers in the piezoelectric composite layer, ensuring the effectiveness of the internal electric field in the piezoelectric phase during the polarization and actuation processes, avoiding the adverse effects of non-ideal polarization and actuation electric fields on the device performance, and facilitating the systematic preparation of the structure and performance of the parallelogram configuration piezoelectric fiber composite.

[0090] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the various embodiments, reference can be made to each other. For the system disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple, and reference can be made to the description in the method part for the relevant parts.

[0091] Specific examples are used in this article to elaborate on the principles and implementation manners of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A piezoelectric composite material, characterized in that, it comprises: an upper interdigital electrode layer, a piezoelectric fiber composite layer, and a lower interdigital electrode layer, which are arranged in sequence from top to bottom; the upper interdigital electrode layer, the piezoelectric fiber composite layer, and the lower interdigital electrode layer are all in a parallelogram structure; a piezoelectric ceramic fiber array is embedded in the piezoelectric fiber composite layer; the piezoelectric ceramic fiber array is in a parallelogram structure; the range of the acute angle in the parallelogram structure is 30° - 60°.

2. The piezoelectric composite material according to claim 1, characterized in that, a first polymer colloid layer is provided between the upper interdigital electrode layer and the piezoelectric fiber composite layer; a second polymer colloid layer is provided between the piezoelectric fiber composite layer and the lower interdigital electrode layer.

3. The piezoelectric composite material according to claim 1, characterized in that, the piezoelectric ceramic fiber array comprises a plurality of piezoelectric ceramic blocks; the shapes and sizes of the plurality of piezoelectric ceramic blocks are the same; the plurality of piezoelectric ceramic blocks are all in a parallelogram structure; the bottom sides of the plurality of piezoelectric ceramic blocks are in the same pointing direction; and the distance between any two adjacent piezoelectric ceramic blocks is equal.

4. The piezoelectric composite material according to claim 1, characterized in that, the upper interdigital electrode layer comprises: a substrate, a positive electrode, and a negative electrode; the positive electrode and the negative electrode are arranged in an interdigital manner on the same side surface of the substrate; the substrate is in a parallelogram structure.

5. The piezoelectric composite material according to claim 4, characterized in that, the positive electrode comprises a first main electrode line, a second main electrode line, and a plurality of first branch electrode lines; the first main electrode line is arranged along the bottom side of the substrate; the second main electrode line is arranged along the first adjacent side of the bottom side of the substrate; the first adjacent side is the adjacent side with an obtuse angle with the bottom side of the substrate; one end of the first main electrode line and one end of the second main electrode line intersect at the obtuse vertex on the bottom side of the substrate; the length of the first main electrode line is less than the length of the bottom side of the substrate; the length of the second main electrode line is less than the length of the first adjacent side; the plurality of first branch electrode lines are arranged in parallel on the substrate; one end of each of the plurality of first branch electrode lines is connected to the first main electrode line or the second main electrode line; the plurality of first branch electrode lines are all perpendicular to the first adjacent side; the distance between any two adjacent first branch electrode lines is equal.

6. The piezoelectric composite material according to claim 5, characterized in that, the negative electrode comprises a third main electrode line, a fourth main electrode line, and a plurality of second branch electrode lines; the third main electrode line is arranged along the opposite side of the bottom side of the substrate; the fourth main electrode line is arranged along the second adjacent side of the bottom side of the substrate; the second adjacent side is the adjacent side with an acute angle with the bottom side of the substrate; one end of the third main electrode line and one end of the fourth main electrode line intersect at the obtuse vertex on the second adjacent side of the substrate; the length of the third main electrode line is equal to the length of the first main electrode line; The length of the fourth main electrode line is equal to the length of the second main electrode line; A plurality of the second branch electrode lines are arranged in parallel on the substrate; One ends of a plurality of the second branch electrode lines are all connected to the third main electrode line or the fourth main electrode line; a plurality of the second branch electrode lines are all perpendicular to the first adjacent side; The distance between any two adjacent second branch electrode lines is equal.

7. A piezoelectric composite material according to claim 6, wherein, The first branch electrode line and the second branch electrode line are arranged at intervals; The first branch electrode line and the second branch electrode line are only connected to one main electrode line; the main electrode line includes: a first main electrode line, a second main electrode line, a third main electrode line and a fourth main electrode line.

8. A driver, wherein, The driver applies a piezoelectric composite material according to any one of claims 1-7.

9. A preparation method for preparing the driver according to claim 8, wherein, The preparation includes: Pasting a rectangular piezoelectric ceramic thin sheet to be cut on a cutting tape; Setting the direction of the bottom edge of the rectangular piezoelectric ceramic thin sheet as the cutting step direction, setting the direction at a preset angle to the cutting step direction as the cutting direction, and using a cutting machine to cut the rectangular piezoelectric ceramic thin sheet to obtain a plurality of piezoelectric ceramic blocks as a piezoelectric ceramic fiber array; Pouring the melted polymer colloid into the gaps between the plurality of piezoelectric ceramic blocks and curing and forming by using a hot press, and tearing off the cutting tape to obtain a piezoelectric fiber composite layer; Using printed circuit technology, etching a positive electrode and a negative electrode on two parallelogram substrates respectively to obtain an upper interdigital electrode layer and a lower interdigital electrode layer; Bonding the upper interdigital electrode layer to the upper surface of the piezoelectric fiber composite layer by using a polymer colloid, bonding the lower interdigital electrode layer to the lower surface of the piezoelectric fiber composite layer by using a polymer colloid, and then performing a curing treatment to obtain a piezoelectric composite material according to any one of claims 1-7; Welding wires on the upper interdigital electrode layer and the lower interdigital electrode layer respectively, and applying a DC voltage to the piezoelectric composite material through the wires for polarization treatment to obtain the driver.

10. A preparation method according to claim 9, wherein, The range of the preset angle is 30°-60°.

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