CN114018447B - Flexible capacitive pressure sensor based on origami structure - Google Patents

Abstract

The application provides a flexible capacitive pressure sensor based on paper folding structure, it includes: the paper folding device comprises a paper folding part body, wherein the surface of the paper folding part body is provided with a plurality of paper folding surfaces which are mutually bent and connected, and when the paper folding part body is pressed along the height direction of the paper folding part body, the sizes of the paper folding part body along the length direction and the width direction of the paper folding part body are increased; the first electrode is arranged on the paper folding surface on one side of the paper folding part body; a second electrode provided on the other side surface of the paper folding portion body. The flexible capacitive pressure sensor based on the paper folding structure can deform when being loaded, so that the relative position relation of the first electrode and the second electrode is adjusted, the capacitance has obvious variation, and the sensitivity of the capacitive pressure sensor is improved.

Description

Flexible capacitive pressure sensor based on origami structure

technical field

The present application relates to the technical field of capacitive pressure sensors, and in particular, to a flexible capacitive pressure sensor based on an origami structure.

Background technique

The capacitive pressure sensor can convert the external pressure signal into the change of capacitance, and convert the change of capacitance into the electrical signal output through the measuring circuit. Compared with resistive pressure sensors, capacitive pressure sensors have the advantages of high sensitivity, low power consumption, compact layout, and high resistance to temperature fluctuations and thermal noise.

SUMMARY OF THE INVENTION

In order to further improve the sensitivity of the capacitive pressure sensor, the present application provides a flexible capacitive pressure sensor based on an origami structure.

The origami-based flexible capacitive pressure sensor includes:

The origami part body, the surface of the origami part body is a plurality of origami surfaces that are bent and connected to each other, when the origami part body is subjected to pressure along its height direction, the origami part body along its length direction and width direction increase in size;

a first electrode, which is arranged on the origami surface of one side of the origami body;

The second electrode is provided on the other side surface of the origami body.

In at least one embodiment, on one side surface and the other side surface of the origami body, a cutting plane is provided at the connection between the adjacent origami surfaces.

In at least one embodiment, a bearing film is further provided between the folding part body and the second electrode.

In at least one embodiment, the carrier film is made of the same material as the origami body, and both are elastic materials.

In at least one embodiment, the elastic material comprises polydimethylsiloxane and/or copolyester.

In at least one embodiment, the first electrode and the second electrode are made of the same material, and are one of liquid metal, silver nanowires, carbon black, graphite, and conductive rubber.

In at least one embodiment, the flexible capacitive pressure sensor based on the origami structure further includes a lead-out part, and the lead-out part is used for outputting the information of the first electrode and the second electrode.

In at least one embodiment, in an unstressed state, the origami surface and the other side surface of the origami part body have an included angle, and the origami part body is subjected to a force along the height direction. Under the state of pressure, the angle between the folding surface and the other side surface becomes smaller, so that the dimensions of the folding body body along the length direction and the width direction increase.

In at least one embodiment, the first electrode includes a plurality of sub-electrodes spaced apart along the width direction and extending along the length direction.

In at least one embodiment, the lead-out part includes a lead-out block and a plurality of lead-out bars, each lead-out bar is connected to one of the sub-electrodes, and the lead-out block gathers the signals of the first electrode and the second electrode lead out.

The flexible capacitive pressure sensor based on the origami structure can deform when subjected to load, thereby adjusting the relative positional relationship between the first electrode and the second electrode, and the capacitance has a significant change, which increases the sensitivity of the capacitive pressure sensor.

Description of drawings

FIG. 1 shows a schematic structural diagram of a flexible capacitive sensor based on an origami structure according to an embodiment of the present application.

FIG. 2 shows a schematic structural diagram of the origami body in FIG. 1 .

FIG. 3 shows a schematic structural diagram of the first electrode in FIG. 1 .

FIG. 4 shows a schematic structural diagram of the second electrode in FIG. 2 .

FIG. 5 shows a schematic structural diagram of the single-piece first electrode in FIG. 3 .

FIG. 6 is a diagram showing the positional relationship between the first electrode and the second electrode of the flexible capacitive sensor based on the origami structure according to an embodiment of the present application.

Description of reference numerals

1 origami part; 11 origami part body; 111 origami surface; 112 cutting plane; 12 first electrode; 121, 122, 123, 124, 125 sub-electrodes; 13 second electrode; 14 carrier film; 2 lead-out part; 21 lead-out strip ;22 lead out block.

Detailed ways

Exemplary embodiments of the present application are described below with reference to the accompanying drawings. It should be understood that these specific descriptions are only used to teach those skilled in the art how to implement the present application, and are not used to exhaust all possible ways of the present application, nor to limit the scope of the present application.

As shown in FIG. 1 , the capacitive pressure sensor based on an origami structure (hereinafter, sometimes referred to as “pressure sensor”) provided by the present application includes an origami part 1 and a lead-out part 2 . The origami part 1 is used as the probe of the pressure sensor to convert the pressure signal into the change of capacitance. The lead-out part 2 is used for outputting the capacitance change detected by the folding part 1 to an external device.

The folding section 1 includes a folding section body 11 , a first electrode 12 and a second electrode 13 .

As shown in FIG. 2 , the origami body 11 is a structure with in-plane negative Poisson’s ratio and out-of-plane positive Poisson’s ratio (described later) designed based on the Miura origami structure. The origami body 11 includes a plurality of origami surfaces 111 in the shape of a parallelogram. Similar to origami, the origami surfaces 111 are connected to each other.

On one side surface of the origami part body 11 (the surface where the folds on one side of the origami part body 11 are located) and the other side surface (the surface where the other side creases of the origami part body 11 are located), adjacent origami surfaces A cutting plane 112 is provided at the connection of 111 . Compared with the original Miura origami structure, when the origami body 11 is folded, the thickness at the crease is reduced, which makes it easier to achieve large-area folding displacement of the origami portion 11 .

The origami body 11 can be made by mixing one or more of polydimethylsiloxane (PDMS), copolyester (ecoflex) or other elastic materials. The origami body 11 can be prepared by mold casting or 3D printing. Elastic materials have higher compressibility, lower Young's modulus, and can obtain greater deformation under stress, which ultimately leads to greater capacitance changes.

A first electrode 12 is provided on the folding surface 111 on the top surface of the folding body 11 . The material of the first electrode may be stretchable conductive materials such as liquid metal, silver nanowires, carbon black, graphite, conductive rubber, and the like. Exemplarily, when the origami body 11 is in a semi-cured state, the first electrode may be directly coated on the origami surface 111 .

As shown in FIG. 3 , the first electrode 12 coated on the origami surface 111 can also be divided into a plurality of sub-electrodes 121 , 122 , 123 , 124 , 125 , etc., and each sub-electrode can be opposed to the single second electrode 13 Independent capacitance changes. Under the action of the external load, the capacitance of each sub-electrode changes. Combined with the capacitance calculation formula (described later), the load distribution can be obtained inversely according to the change value of each capacitance.

As shown in FIG. 4 , a carrier film 14 is provided on the bottom surface of the origami body 11 , for example, the carrier film 14 can be connected to the cutting plane 112 . The material of the carrier film 14 may be the same as that of the origami body 11 . Exemplarily, the thickness of the film 2 may be 0.05mm-5mm, preferably 2mm.

The second electrode 13 may be provided on the side of the carrier film 14 away from the folding part 11 . Likewise, the second electrode 13 can be made of the same material as the first electrode 12 . The second electrode 13 can be coated on the carrier film 14 first, and the carrier film 14 and the second electrode 13 can be directly pasted to the bottom surface of the origami portion 11 when the origami body 11 is in a semi-cured state.

As shown in FIGS. 5 and 6 , taking an origami surface 111 as an example, the first electrode 12 thereon is also a parallelogram. When no force is applied, the acute angle in the first electrode 12 is α, the length of the side of the first electrode 12 parallel to the other side surface is a, and the side length of the other side is b. The first electrode 12 has an included angle θ with the other side surface, and the distance between the lowest point of the first electrode 12 and the second electrode 13 is d. According to the formula, it can be obtained that the deformation relationship between the capacitance C and the first electrode 12 is:

Among them, ε ₀ is the dielectric constant of the first electrode 12 and the second electrode 13 .

面外泊松比

For the convenience of introduction, the present application introduces coordinate systems in the length direction X, the width direction Y, and the height direction Z. The length of the origami body 11 is L, the width is W, and the height is H. In-plane Poisson's ratio of the origami body 11

Out-of-plane Poisson's ratio

When the origami body 11 is pressed down in the height direction Z, ΔW (change in width) and ΔL (change in length) are positive values, and ΔH (change in height) is a negative value, that is, the surface of the origami body 11 The inner Poisson's ratio is negative and the out-of-plane Poisson's ratio is positive.

The position of the first electrode 12 can be changed with the deformation of the origami body 11 , and then the capacitance between the first electrode 12 and the second electrode 13 is changed. The in-plane negative Poisson's ratio and the out-of-plane positive Poisson's ratio of the origami body 11 multiply the capacitance change, making the capacitance sensor more sensitive.

As shown in FIG. 1 , the lead-out portion 2 may be a lead-out structure for connecting the origami portion 1 . Exemplarily, the lead-out portion 2 may include a plurality of lead-out bars 21 and lead-out blocks 22 . Each lead-out bar 21 corresponds to one sub-electrode of the first electrode 12 extending along the length direction X. As shown in FIG. Then, the signals of the first electrode 12 and the second electrode 13 are gathered together through the lead-out block 22 and led out uniformly.

The constituent material of the capacitive sensor is an elastic material, which has a very large deformation under the action of the normal load (the direction of the normal load is parallel to the height direction Z), which makes the pressure measurement range of the pressure sensor very wide and the sensitivity is high.

Further, the optimal design of the pressure sensor can be carried out. When the pressure sensor is subjected to a tangential load (for example, the direction of the tangential load is parallel to the width direction Y), the two groups of sub-electrodes of the first electrode 12 have different deformation degrees, and can pass through the space between the two groups of sub-electrodes and the second electrode 13 The capacitance difference calculates the force. The pressure sensor can detect both normal load and tangential load.

The above are the preferred embodiments of the present application. It should be pointed out that for those skilled in the art, some improvements and modifications can be made without departing from the principles of the present application, and these improvements and modifications should also be regarded as the present invention. The scope of protection applied for.

Claims (8)

1. A flexible capacitive pressure sensor based on an origami structure, wherein the flexible capacitive pressure sensor based on an origami structure comprises: The origami part body (11), the surface of the origami part body (11) is a plurality of origami surfaces (111) which are bent and connected to each other, and the origami part body (11) is subjected to pressure along the height direction (Z) of the origami part body (11). When pressed, the dimensions of the origami body (11) along its length direction (X) and width direction (Y) increase; A first electrode (12), the first electrode (12) is disposed on the origami surface (111) on one side of the origami body (11), and the first electrode (12) includes an area along the width a plurality of sub-electrodes (121, 122, 123, 124, 125) spaced in direction (Y) and extending along said length direction (X); a second electrode (13), the second electrode (13) is provided on the other side surface of the origami body (11), On one side surface and the other side surface of the origami body (11), a cutting plane (112) is provided at the connection between the adjacent origami surfaces (111), and the plurality of sub-electrodes are at the width of Separated by the cutting plane (112) in the direction (Y), each of the sub-electrodes can form a relatively independent capacitance change with the second electrode (13) of the single block, When the origami body (11) receives a load parallel to the width direction (Y), the angle between the origami surface (111) and the second electrode (13) changes, and the plane is cut by the cutting plane. (112) The two separated sub-electrodes have different deformation degrees. 2 . The flexible capacitive pressure sensor based on the origami structure according to claim 1 , wherein a bearing film ( 14 ) is further provided between the origami body ( 11 ) and the second electrode ( 13 ). 3 . . 3 . The flexible capacitive pressure sensor based on the origami structure according to claim 2 , wherein the carrier film ( 14 ) is made of the same material as the origami body ( 11 ), and both are elastic materials. 4 . 4. The flexible capacitive pressure sensor based on an origami structure according to claim 3, wherein the elastic material comprises polydimethylsiloxane and/or copolyester. 5. The flexible capacitive pressure sensor based on an origami structure according to claim 1, wherein the first electrode (12) and the second electrode (13) are made of the same material, and are liquid metal, silver One of nanowires, carbon black, graphite, conductive rubber. 6 . The flexible capacitive pressure sensor based on the origami structure according to claim 1 , wherein the flexible capacitive pressure sensor based on the origami structure further comprises a lead-out portion ( 2 ), and the lead-out portion ( 2 ) uses for outputting the information of the first electrode (12) and the second electrode (13). 7 . The flexible capacitive pressure sensor based on the origami structure according to claim 1 , characterized in that, in an unstressed state, the origami surface ( 111 ) and the origami body ( 11 ) of the The other side surface has an included angle, and the included angle between the origami surface (111) and the other side surface when the origami body (11) is subjected to pressure along the height direction (Z) The size of the origami body (11) along the length direction (X) and the width direction (Y) increases. 8. The flexible capacitive pressure sensor based on an origami structure according to claim 6, wherein the lead-out portion (2) comprises a lead-out block (22) and a plurality of lead-out bars (21), each lead-out The strip (21) is connected to one of the sub-electrodes, and the lead-out block (22) gathers and leads out the signals of the first electrode (12) and the second electrode (13).

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