Piezoelectric sensor based on superlattice structure and manufacturing method

Abstract

The invention relates to a piezoelectric sensor based on a superlattice structure and a manufacturing method, the piezoelectric sensor comprises a plurality of piezoelectric fibers, the piezoelectric fibers are bent into a periodic shape, and the periodic shape comprises an arrow shape or a semi-honeycomb shape; the bent piezoelectric fibers are sequentially connected to form a piezoelectric fiber net, and the piezoelectric fiber net is attached to the complex curved surface; the manufacturing method adopts the structure. Compared with the prior art, the bent piezoelectric fibers are sequentially connected to form the piezoelectric fiber net, the piezoelectric fiber net can be attached to a complex curved surface, and data collection is more accurate; a plurality of piezoelectric fibers are applied, a shielding electrode and a core electrode are led out of the two sides of each piezoelectric fiber respectively and serve as a grounding electrode and signal electricity, and multi-channel pressure sensing is provided; the preparation method is low in cost and can realize large-scale production; the expandability is high, and the number of the piezoelectric fibers can be increased or decreased according to the attaching area.

Description

Technical Field

[0001] The present invention relates to the field of sensor technology, and in particular to a piezoelectric sensor based on a superlattice structure and a manufacturing method thereof. Background Art

[0002] With the booming development of the Internet of Things and consumer electronic products, flexible sensors, as key devices for the development of both, are attracting widespread attention in various fields. The development of new flexible piezoelectric sensors with excellent performance and meeting the needs of specific scenarios has important application value in the fields of health care, human-computer interaction, robot sensing, smart home, ergonomic design, etc.

[0003] Flexible piezoelectric sensors can convert mechanical signals into electrical signals that are easy to transmit and analyze. They can be integrated into electronic products that are in close contact with the human body, such as watches, mice, and clothing, to realize intelligent detection functions. They can also be attached to the surface of the robot shell to realize robot electronic skin. This is an indispensable technology for future consumer electronic products.

[0004] The invention patent with publication number WO2016175321A1 discloses a cord-shaped piezoelectric element, which has a core formed by conductive fibers and a sheath formed by cord-shaped piezoelectric fibers in a manner of covering the core, wherein the piezoelectric fibers contain polylactic acid as a main component, and the winding angle of the piezoelectric fibers relative to the conductive fibers is greater than 15° and less than 75°. This patent lacks adaptability to complex curved surfaces, cannot overcome device wrinkles during the attachment process, and lacks multi-channel pressure sensing.

[0005] Therefore, providing a piezoelectric sensor that can adapt to complex surfaces and multi-channel pressure perception is an urgent problem to be solved. Summary of the invention

[0006] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide a piezoelectric sensor based on a superlattice structure and a manufacturing method thereof.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] According to a first aspect of the present invention, a piezoelectric sensor based on a superlattice structure is provided, comprising a plurality of piezoelectric fibers, wherein the piezoelectric fibers are bent into a periodic shape, wherein the periodic shape includes an arrow shape or a semi-honeycomb shape; the bent piezoelectric fibers are connected in sequence to form a piezoelectric fiber mesh, and the piezoelectric fiber mesh fits a complex curved surface.

[0009] As a preferred technical solution, the arrow type includes long arrows and short arrows; the multiple piezoelectric fibers are equally divided into two parts, one part of the piezoelectric fibers is bent into a periodic shape as a long arrow, and the other part of the piezoelectric fibers is bent into a periodic shape as a short arrow.

[0010] As a preferred technical solution, the long arrow is bent with a side length of 3 cm and an angle of 60°; the short arrow is bent with a side length of 1 cm and an angle of 120°.

[0011] As a preferred technical solution, the two ends of the long arrow and the short arrow are connected to form an adhesion portion; the long arrow of one piezoelectric fiber and the short arrow of another piezoelectric fiber form a group of piezoelectric fibers.

[0012] As a preferred technical solution, the vertices of the long arrows of the group of piezoelectric fibers are connected to the vertices of the short arrows of the other group of piezoelectric fibers to form an adhesion portion.

[0013] As a preferred technical solution, the semi-honeycomb type is bent with side lengths of 3 cm and 1 cm respectively, the long side is parallel to the horizontal plane, and the angle between the short side and the horizontal plane is 60°.

[0014] As a preferred technical solution, the semi-honeycomb piezoelectric fibers are connected alternately in forward and reverse directions to form an adhesion portion.

[0015] As a preferred technical solution, the connection method of the adhesive portion includes hot melting or gluing.

[0016] As a preferred technical solution, a shielding electrode and a core electrode are respectively led out from both sides of the piezoelectric fiber to serve as a ground electrode and a signal electrode.

[0017] According to another aspect of the present invention, a method for manufacturing a piezoelectric sensor based on a superlattice structure as described above is provided, wherein the manufacturing process of the piezoelectric sensor comprises the following steps:

[0018] S1, bending the piezoelectric fiber into an arrow shape or a semi-honeycomb shape;

[0019] S2, connecting the bent piezoelectric fibers in sequence to form a piezoelectric fiber network;

[0020] S3. Fit the piezoelectric fiber mesh to the complex curved surface.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The present invention connects the bent piezoelectric fibers in sequence to form a piezoelectric fiber mesh, and the piezoelectric fiber mesh can fit complex curved surfaces, and collect data more accurately.

[0023] 2. The present invention uses multiple piezoelectric fibers, and shielding electrodes and core electrodes are respectively led out on both sides of the piezoelectric fibers as ground electrodes and signal electrodes, providing multi-channel pressure sensing.

[0024] 3. The present invention has low cost and can be produced on a large scale.

[0025] 4. The present invention has strong scalability and can increase or decrease the number of decompression and pressure relief fibers according to the bonding area. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the structure of the piezoelectric sensor with a negative Poisson's ratio double arrow of the present invention;

[0027] Figure 2 This is a schematic diagram of the disassembled structure of the long arrow of the negative Poisson's ratio double arrow of the present invention;

[0028] Figure 3 It is a schematic diagram of the disassembled structure of the short arrow of the negative Poisson's ratio double arrow of the present invention;

[0029] Figure 4 It is a schematic diagram of the structure of a piezoelectric sensor with a negative Poisson's ratio honeycomb structure of the present invention;

[0030] Figure 5 It is a schematic diagram of the split structure of the piezoelectric sensor of the negative Poisson's ratio honeycomb structure of the present invention;

[0031] Figure 6 This is a schematic diagram of the structure of an electrical sensor with a positive Poisson's ratio honeycomb structure of the present invention;

[0032] Figure 7 This is a schematic diagram of the disassembled structure of the electrical sensor of the positive Poisson's ratio honeycomb structure of the present invention;

[0033] Figure 8 It is a schematic diagram of the structure of a zero Poisson's ratio honeycomb structure piezoelectric sensor of the present invention;

[0034] Fig. 9 This is a schematic diagram of the disassembled structure of the zero Poisson's ratio honeycomb structure piezoelectric sensor of the present invention;

[0035] Fig.10 The present invention is a flow chart of the sensor manufacturing method.

[0036] 1. Long arrow; 2. Short arrow; 3. Semi-honeycomb type; 4. Adhesion part. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0038] Certain special scenarios have put forward higher-level requirements for flexible piezoelectric sensors, such as high sensitivity, excellent mechanical properties, and the ability to conform to complex surfaces. Among them, conforming to complex surfaces is very difficult for general thin-film piezoelectric sensors. Piezoelectric fiber mesh sensors with superlattice structures (negative Poisson's ratio structure, positive Poisson's ratio structure, zero Poisson's ratio structure) have very excellent mechanical properties. For example, the negative Poisson's ratio structure has the property of bending out of the plane to form a unidirectional curved surface rather than the saddle-shaped curved surface of the traditional structure. The special function of this structure helps the sensor itself to conform to complex surfaces more easily, such as the joints of the human body, the outer surface of robots, and the outer surface of precision instruments, etc., to achieve deformation of complex surfaces and realize accurate real-time monitoring.

[0039] The present invention forms a superlattice structure by bending piezoelectric fibers into a periodic shape and connecting them in sequence. The superlattice structure can better fit complex curved surfaces, have better mechanical properties, and achieve accurate real-time monitoring of deformation on complex curved surfaces.

[0040] Example 1

[0041] like Figure 1-Figure 3 As shown, a method for manufacturing a piezoelectric sensor based on a superlattice structure includes a plurality of piezoelectric fibers, wherein the piezoelectric fibers are bent into a periodic shape, wherein the periodic shape includes an arrow shape or a semi-honeycomb shape 4; the bent piezoelectric fibers are connected in sequence to form a piezoelectric fiber mesh, wherein the piezoelectric fiber mesh fits a complex curved surface.

[0042] The arrow shape includes a long arrow 1 and a short arrow 2; the multiple piezoelectric fibers are equally divided into two parts, one part of the piezoelectric fibers is bent into a periodic shape as the long arrow 1, and the other part of the piezoelectric fibers is bent into a periodic shape as the short arrow 2.

[0043] The long arrow 1 is bent with a side length of 3 cm and an angle of 60°; the short arrow 2 is bent with a side length of 1 cm and an angle of 120°.

[0044] The two ends of the long arrow 1 and the short arrow 2 are connected to form an adhesion portion 3; the long arrow 1 of one piezoelectric fiber and the short arrow 2 of another piezoelectric fiber form a group of piezoelectric fibers.

[0045] The vertices of the long arrows 1 of the group of piezoelectric fibers are connected to the vertices of the short arrows 2 of the other group of piezoelectric fibers to form adhesion portions 3 .

[0046] In this embodiment, the preparation process of the double-arrow piezoelectric fiber net includes: selecting 5 30cm long IXPP piezoelectric fibers and 5 10cm long IXPP piezoelectric fibers; bending 30cm of the piezoelectric fiber material into a long arrow 1, with an angle of 60° and a side length of 3cm, and bending the remaining 10cm of the piezoelectric fiber into a short arrow 2, with an angle of 30° and a side length of 1cm; connecting the bent piezoelectric fibers in sequence to form a piezoelectric fiber net, forming a negative Poisson's ratio double-arrow structure. The number of piezoelectric fibers can be increased or decreased according to the size of the area to be bonded.

[0047] The semi-honeycomb type 4 is bent with side lengths of 3 cm and 1 cm respectively, the long side is parallel to the horizontal plane, and the angle between the short side and the horizontal plane is 60°.

[0048] The piezoelectric fibers of the semi-honeycomb type 4 are connected alternately in positive and negative directions to form an adhesion portion 3 .

[0049] In this embodiment, 10 40 cm long PVDF piezoelectric fibers are selected; all piezoelectric fiber materials are bent into a semi-honeycomb type 4, which is bent with side lengths of 3 cm and 1 cm, and is bent into five units, with the long side parallel to the horizontal plane and the short side having an angle of 60° with the horizontal plane; the bent piezoelectric fibers are connected in sequence to form a piezoelectric fiber network, forming a honeycomb structure.

[0050] In this embodiment, the superlattice structure includes a negative Poisson's ratio structure, a positive Poisson's ratio structure and a zero Poisson's ratio structure. The piezoelectric sensor structure of the negative Poisson's ratio honeycomb structure is as follows: Figure 4 , Figure 5 shown.

[0051] The electrical sensor structure of the positive Poisson's ratio honeycomb structure is as follows Figure 6 , Figure 7 shown.

[0052] Zero Poisson's ratio honeycomb piezoelectric sensor structure Figure 8 , Fig. 9 shown.

[0053] The connection method of the bonding part 3 includes hot melting or gluing.

[0054] In the negative Poisson's ratio structure, the structure with a smaller inner angle is easier to deform to adapt to the curved surface. In this embodiment, the piezoelectric fiber mesh prepared by combining different Poisson's ratio structures can fit well with various special-shaped curved surfaces, so the surface of the special-shaped structure can be wrapped by adjusting the angle, and the state monitoring of the complex external surface object can be realized.

[0055] In this embodiment, the bonding part includes point bonding and line bonding, which are connected by hot melting or gluing.

[0056] A shielding electrode and a core electrode are respectively led out from both sides of the piezoelectric fiber to serve as a ground electrode and a signal electrode; the multiple piezoelectric fibers form a multi-channel detection to improve the detection accuracy.

[0057] In this embodiment, shielding electrodes and core electrodes are led out from both sides of all piezoelectric fibers, which are ground electrodes and signal electrodes respectively; multi-channel detection is formed to improve detection accuracy; the piezoelectric fibers include a series of similar linear piezoelectric fibers such as IXPP, PVDF, and PFA.

[0058] In this embodiment, the sensor is also flexible, and multi-channel pressure sensing can make the collected data present a surface distribution, providing users with a more detailed and accurate data set. The characteristics of the sensor can be replicated according to the use area and scene, making it more convenient to put it into use. Users can achieve complex and large-area sensing coverage by infinitely replicating the unit structure. For example, the double-arrow structure is a negative Poisson's ratio structure, which can provide better mechanical properties: fit complex surfaces and resist impact.

[0059] Example 2

[0060] like Fig.10 As shown, a method for manufacturing a piezoelectric sensor based on a superlattice structure, the manufacturing process of the piezoelectric sensor includes the following steps:

[0061] S1, bending the piezoelectric fiber into an arrow shape or a semi-honeycomb shape;

[0062] S2, connecting the bent piezoelectric fibers in sequence to form a piezoelectric fiber network;

[0063] S3. Fit the piezoelectric fiber mesh to the complex curved surface.

[0064] In this embodiment, a suitable number of piezoelectric fibers can be selected according to the size of the bonding area to form a piezoelectric fiber mesh of suitable size.

[0065] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A piezoelectric sensor based on a superlattice structure, comprising a plurality of piezoelectric fibers, characterized in that: The piezoelectric fibers are bent into a periodic shape, wherein the periodic shape includes an arrow shape or a semi-honeycomb shape (4); the bent piezoelectric fibers are connected in sequence to form a piezoelectric fiber mesh, and the piezoelectric fiber mesh fits a complex curved surface.

2. A piezoelectric sensor based on a superlattice structure according to claim 1, characterized in that: The arrow shape includes a long arrow (1) and a short arrow (2); the plurality of piezoelectric fibers are equally divided into two parts, one part of the piezoelectric fibers is bent into a periodic shape as the long arrow (1), and the other part of the piezoelectric fibers is bent into a periodic shape as the short arrow (2).

3. A piezoelectric sensor based on a superlattice structure according to claim 2, characterized in that: The long arrow (1) is bent with a side length of 3 cm and an angle of 60°; the short arrow (2) is bent with a side length of 1 cm and an angle of 120°.

4. A piezoelectric sensor based on a superlattice structure according to claim 3, characterized in that: The two ends of the long arrow (1) and the short arrow (2) are connected to form an adhesion portion (3); the long arrow (1) of one piezoelectric fiber and the short arrow (2) of another piezoelectric fiber form a group of piezoelectric fibers.

5. The piezoelectric sensor based on a superlattice structure according to claim 4, characterized in that: The vertices of the long arrows (1) of the group of piezoelectric fibers are connected to the vertices of the short arrows (2) of the other group of piezoelectric fibers to form an adhesion portion (3).

6. The piezoelectric sensor based on a superlattice structure according to claim 1, characterized in that: The semi-honeycomb type (4) is bent with side lengths of 3 cm and 1 cm respectively, the long side is parallel to the horizontal plane, and the angle between the short side and the horizontal plane is 60°.

7. The piezoelectric sensor based on a superlattice structure according to claim 6, characterized in that: The piezoelectric fibers of the semi-honeycomb type (4) are connected alternately in positive and negative directions in sequence to form an adhesion portion (3).

8. The piezoelectric sensor based on a superlattice structure according to claim 7, characterized in that: The connection method of the adhesive portion (3) includes hot melting or gluing.

9. The piezoelectric sensor based on a superlattice structure according to claim 8, characterized in that: A shielding electrode and a core electrode are respectively led out from two sides of the piezoelectric fiber to serve as a ground electrode and a signal electrode.

10. A method for manufacturing a piezoelectric sensor based on a superlattice structure according to any one of claims 1 to 9, characterized in that: The manufacturing process of the piezoelectric sensor comprises the following steps: S1, bending the piezoelectric fiber into an arrow shape or a semi-honeycomb shape; S2, connecting the bent piezoelectric fibers in sequence to form a piezoelectric fiber network; S3. Fit the piezoelectric fiber mesh to the complex curved surface.

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