Liquid drop jetting speed and direction array type sensing system based on friction nanometer generator

Abstract

A liquid drop spraying speed and direction sensing system based on a friction nanometer generator comprises an electrode layer and a dielectric layer which are sequentially arranged on a substrate layer, and a measuring circuit connected with the electrode layer, and the electrode layer is of an array structure formed by combining at least two independent electrodes; according to the invention, the theory of a parallel plate capacitor in the friction nano-generator theory is adopted, the accurate liquid drop spraying speed and direction can be obtained in a short calculation time, and the device has the advantages of low cost, small size and easiness in integration.

Description

Technical Field

[0001] The invention relates to a droplet sensing technology, in particular to a droplet jetting speed and direction array sensor based on a friction nanogenerator. Background Art

[0002] As a droplet ejection technology, inkjet printing has always been an important topic in the fields of graphic printing, additive manufacturing, biomedicine, and flexible electronics. The ejection speed and direction of the droplets will affect the accuracy and reliability of printing and need to be identified quickly and accurately. Currently, the measurement of droplet status is usually achieved through imaging technology (such as high-speed cameras, stroboscopic technology, confocal microscopy, etc.). Many printing instruments on the market have integrated cameras to monitor printing quality, but imaging technology has disadvantages such as high cost, large size, target occlusion, and light interference. Summary of the invention

[0003] In view of the fact that the existing technology cannot solve the problem of identifying the injection speed and direction of droplets when they impact a solid surface, the present invention proposes a droplet injection speed and direction array sensing system based on a friction nanogenerator. By adopting the parallel plate capacitor theory in the friction nanogenerator mechanism, the accurate droplet injection speed and direction can be obtained in a short computing time, and the system has the advantages of low cost, small size and easy integration.

[0004] The present invention is achieved through the following technical solutions:

[0005] The present invention relates to a droplet injection speed and direction sensing system based on a friction nanogenerator, comprising: an electrode layer and a dielectric layer sequentially arranged on a substrate layer, and a measurement circuit respectively connected to the electrode layer, wherein: the electrode layer is an array structure composed of at least two independent electrodes.

[0006] The electrode layer is above the substrate layer, the dielectric layer is above the electrode layer, and the liquid droplets are sprayed on the upper surface of the dielectric layer.

[0007] The measuring circuit includes a measuring unit, a storage unit and a calculation unit, wherein: the measuring unit is respectively connected to the independent electrodes and the ground positions of the electrode layer, and detects the voltage change accumulated when the droplet hits the dielectric layer, the storage unit records the voltage change values ​​of all independent electrodes, and the calculation unit calculates the ejection speed and ejection direction of the droplet according to the sum and ratio of the voltage change values, that is, Where: f1 represents the calibrated characteristic curve of the injection velocity sensor, f2 represents the calibrated characteristic curve of the injection direction sensor, V ip , i=1, 2, 3, 4 are the voltage change values ​​measured on four independent electrodes below the droplet impact position.

[0008] The sensor characteristic curve is obtained by experimental calibration after preparing a droplet jetting sensor system having a dielectric layer, an electrode layer, a substrate layer and a measuring circuit, with the droplet material and volume fixed.

[0009] The dielectric layer is preferably made of polydimethylsiloxane, and the surface is treated to be super-hydrophobic.

[0010] The electrode layer is preferably made of copper foil and is divided into two groups of independent electrodes that are orthogonal to each other, and each group of independent electrodes is composed of a number of parallel strip electrodes.

[0011] The area of ​​the substrate layer is preferably larger than that of the dielectric layer. Technical Effects

[0012] The present invention is based on the theory of parallel plate capacitors in the solid-liquid friction nanogenerator mechanism, and realizes a self-sensing array for droplet ejection speed and direction through a single-electrode mode friction nanogenerator unit. When the droplet is ejected onto a dielectric layer with a conductive layer underneath, the charge is transferred and accumulated during the droplet spreading and retraction period, and finally the droplet and the electrode layer carry charges of opposite polarities. The droplet and the electrode layer are used as conductors, and the dielectric layer is used as a dielectric, forming a parallel plate capacitor as a whole. This parallel plate capacitor can be regarded as a parallel connection of parallel plate capacitors corresponding to each independent electrode, so there is a one-to-one correspondence between the sum of the open circuit voltages measured on each independent electrode and the droplet ejection speed, and there is a one-to-one correspondence between the ratio of the open circuit voltages measured on each independent electrode and the droplet ejection direction, so that accurate droplet ejection speed and direction can be obtained in a short computing time. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the structure of the present invention;

[0014] In the figure: 1 dielectric layer, 2 electrode layer, 3 substrate layer, 4 measurement circuit;

[0015] Figure 2 It is a schematic diagram of the explosion of the structure of the present invention;

[0016] Figure 3 It is a schematic diagram of the structure of an embodiment;

[0017] Figure 4 Schematic diagram of characteristic curve of droplet jetting velocity sensor in the embodiment;

[0018] Figure 5 Schematic diagram of characteristic curve of droplet ejection direction sensor in the embodiment;

[0019] Figure 6 It is a schematic diagram of the effect of the embodiment;

[0020] Figure 7Schematic diagram of the electrification principle of the embodiment. DETAILED DESCRIPTION

[0021] like Figure 3 As shown, this embodiment relates to a droplet injection speed and direction sensing system based on a friction nanogenerator, comprising: an electrode layer 2 and a dielectric layer 1 sequentially arranged on a substrate layer 3, and a measurement circuit 4 connected to the electrode layer 2, wherein: the electrode layer 2 is composed of four independent electrodes.

[0022] After specific practical experiments, when the dielectric layer is a 2cm×2cm polydimethylsiloxane film and a water droplet with a diameter of 4mm impacts the sensor, the calibration results are as follows: Figure 4 The droplet jet velocity sensor characteristic curve f1 is shown as V 1p +V 2p +V 3p +V 4p =-1036.1v 2 +194.7, as Figure 5 The droplet ejection direction sensor characteristic curve f2 is shown as From the symmetry we can get

[0023] like Figure 6 As shown in FIG. 1 , it is a comparison diagram of the actual droplet ejection direction of this embodiment and the droplet ejection direction measured by this embodiment. Figure 7 As shown, the actual injection direction is very close to the measured injection direction, and the maximum relative error in the range of ([-2mm, 2mm], [-2mm, 2mm]) is 4.1%.

[0024] Compared with the prior art, the present invention has the advantages of low cost, simple manufacture and easy integration.

[0025] The above-mentioned specific implementation can be partially adjusted in different ways by those skilled in the art without departing from the principle and purpose of the present invention. The protection scope of the present invention shall be based on the claims and shall not be limited by the above-mentioned specific implementation. Each implementation scheme within its scope shall be subject to the constraints of the present invention.

Claims

1. A droplet jetting velocity and direction sensing system, characterized in that: It includes a substrate layer, an electrode layer, a dielectric layer, and a measuring circuit connected to the electrode layer, wherein the electrode layer is an array structure composed of at least two independent electrodes.

2. The droplet jetting sensor system according to claim 1, characterized in that: The sensing principle is based on triboelectric charging and electrostatic induction, and the droplet, dielectric layer, and electrode layer constitute a parallel plate capacitor.

3. The droplet jetting sensor system according to claim 1, characterized in that: The electrode layer is above the substrate layer, the dielectric layer is above the electrode layer, and the liquid droplets are sprayed on the upper surface of the dielectric layer.

4. The droplet jetting sensor system according to claim 1, characterized in that: The substrate layer is an insulating material such as an acrylic plate or a glass plate.

5. The droplet jetting sensor system according to claim 1, characterized in that: The electrode layer comprises independent electrodes arranged in one direction, and the independent electrodes are insulated from each other; or the electrode layer comprises independent electrodes arranged in two directions, and the independent electrodes are insulated from each other and the independent electrodes in the two directions are insulated from each other; the independent electrodes are conductive materials.

6. The droplet jetting sensor system according to claim 1, characterized in that: The dielectric layer is made of dielectric materials such as polydimethylsiloxane or polytetrafluoroethylene.

7. The droplet jetting sensor system according to claim 1, characterized in that: The measuring circuit includes a measuring unit, a storage unit and a calculation unit, wherein: the measuring unit is respectively connected to the independent electrodes and the ground positions of the electrode layer, and detects the voltage change accumulated when the droplet hits the dielectric layer, the storage unit records the voltage change values ​​of all independent electrodes, and the calculation unit calculates the ejection speed and ejection direction of the droplet according to the sum and ratio of the voltage change values, that is, v=f1 -1 (V 1p +V 2p +V 3p +V 4p ), Where: f1 represents the calibrated characteristic curve of the injection velocity sensor, f2 represents the calibrated characteristic curve of the injection direction sensor, V ip , i=1, 2, 3, 4 are the voltage change values ​​measured on four independent electrodes below the droplet impact position.

8. The droplet jetting sensor system according to claim 1 or 7, characterized in that: The sensor characteristic curve is obtained by experimental calibration after preparing a droplet jetting sensor system having a dielectric layer, an electrode layer, a substrate layer and a measuring circuit, with the droplet material and volume fixed.

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