Transparent pressure sensor and manufacturing method thereof, and switch

Abstract

The present invention discloses a transparent pressure sensor and a manufacturing method and a switch thereof. The transparent pressure sensor includes: an electrode layer, the electrode layer includes a plurality of detection points arranged evenly, each detection point has a positive electrode and a negative electrode arranged opposite to each other and spaced from each other; a transparent pressure-sensitive film, which is arranged above the electrode layer, and when subjected to external pressure toward the electrode layer, at least one detection point of the electrode layer is turned on, and a change in the detection value of the corresponding electrical parameter is generated at each detection point. The transparent pressure sensor of the present invention has a simple structure, is easy to process, and is convenient for mass production.

Description

Technical Field

[0001] The present invention relates to the technical field of transparent pressure sensors, and in particular to a pressure sensor with a simple structure, convenient processing and high transparency, and a manufacturing method thereof. Background Art

[0002] Pressure sensors are commonly used in electronic products. Transparent pressure sensors are the key development direction of pressure sensors because of their wide application range. However, existing transparent pressure sensors have problems such as difficult processing and poor transparency.

[0003] Take the transparent pressure sensor disclosed in the publication number CN106648226A as an example. The structure of the transparent pressure sensor disclosed in the disclosure is two relatively arranged piezoresistive material layers, a conductive electrode located outside the piezoresistive material layer, and a substrate material located outside the conductive electrode. The pressure sensor adopts a double-electrode method. The upper and lower electrodes are connected when subjected to external pressure, so that the corresponding pressure can be detected. Therefore, the upper and lower electrodes of each detection point of the pressure sensor involve the problem of alignment during the processing, which is easy to produce alignment deviation. Moreover, the mutual alignment of the piezoresistive material layer and the conductive electrode will cause many existing processes to be unusable. For example, it cannot be simply made by roller coating. Even if a high-precision printing method is used to align the relatively arranged piezoresistive material layer and the conductive electrode as accurately as possible, the accuracy can only reach 0.1mm, and the difficulty of precise processing is relatively large. In addition, two layers of electrodes plus two layers of piezoresistive material layers will greatly reduce the transparency of the pressure sensor, and will also cause problems such as increased haze.

[0004] Therefore, how to provide a transparent pressure sensor with a simple structure and higher transparency and a manufacturing method thereof is a technical problem that needs to be solved urgently in the industry. Summary of the invention

[0005] In order to solve the technical problems of low transparency and complex structure of transparent pressure sensors in the prior art, the present invention provides a transparent pressure sensor and a manufacturing method thereof, and a switch.

[0006] The transparent pressure sensor proposed by the present invention comprises:

[0007] An electrode layer, wherein the electrode layer comprises a plurality of detection points arranged evenly, wherein the positive electrode and the negative electrode of each detection point are provided with a splicing portion which does not contact each other, and the splicing portions of the positive electrode and the negative electrode have the same shape and structure and are complementary and plugged;

[0008] The transparent pressure-sensitive film is arranged above the electrode layer. When the transparent pressure-sensitive film is subjected to external pressure toward the electrode layer, at least one detection point of the electrode layer is turned on and a change in the detection value of the corresponding electrical parameter is generated at each detection point.

[0009] Furthermore, the splicing portion is in a comb-teeth shape or a spiral shape.

[0010] Furthermore, when the splicing portion is in a comb-teeth shape, the comb teeth of the splicing portion are straight lines or curves.

[0011] Furthermore, the detection points are arranged in an array.

[0012] Furthermore, the electrical parameter includes one or a combination of resistance, voltage, and current between the positive electrode and the negative electrode at the detection point.

[0013] Furthermore, the electrode layer is formed by etching an ITO film or an ITO glass.

[0014] The method for manufacturing the transparent pressure sensor proposed by the present invention comprises the following steps:

[0015] Adding nano silver powder to the polymer material solution to form a mixed slurry and stirring evenly;

[0016] The mixed slurry is made into a transparent pressure-sensitive film;

[0017] Etching the ITO film or ITO glass to form an electrode layer;

[0018] Bonding the transparent pressure-sensitive film and the electrode layer;

[0019] The electrode layer of the bonded transparent pressure-sensitive film is punched out to obtain a transparent pressure sensor.

[0020] Furthermore, making the mixed slurry into a transparent pressure-sensitive film includes: making the mixed slurry into a film on a base belt, and performing multi-stage drying, wherein the drying temperature of each stage is higher than the drying temperature of the previous stage, to form a transparent pressure-sensitive film.

[0021] Further, the mixed slurry is prepared by the following steps:

[0022] Adding nano silver powder into polyvinyl butyral (PVB) resin alcohol solution;

[0023] Add dispersant, defoamer, leveling agent, wetting agent, and nano hollow titanium dioxide with a particle size that meets the preset range;

[0024] Ultrasonic stirring is used to obtain a uniform mixed slurry. The weight percentage of raw materials used to prepare the mixed slurry is: 84-91% polyvinyl butyral (PVB) resin alcohol solution, 0.5-5% nano silver powder, 1-2% nano hollow titanium dioxide, 5% defoamer, 2-3% leveling agent, and 0.5-1% wetting agent.

[0025] Preferably, the weight percentage of raw materials used to prepare the mixed slurry is: 90% polyvinyl butyral (PVB) resin alcohol solution, 1.5% nano silver powder, 1% nano hollow titanium dioxide, 5% defoaming agent, 2% leveling agent, and 0.5% wetting agent.

[0026] The switch provided by the present invention comprises the transparent pressure sensor described in the above technical solution.

[0027] The structure of the transparent pressure sensor of the present invention is composed of a transparent pressure-sensitive film and a conductive electrode layer. The substrate material of the pressure-sensitive layer is eliminated, which can reduce the overall thickness of the sensor. At the same time, the light transmittance of the pressure-sensitive layer is improved and the deflection coefficient is reduced. In addition, since in the technical solution of the present invention, the current flows from the electrode layer to the transparent pressure-sensitive film and then returns from the transparent pressure-sensitive film to the electrode layer, there is no need to pattern the transparent pressure-sensitive film, which reduces the processing difficulty of the transparent pressure-sensitive film. The transparent pressure-sensitive film is non-patterned, so the transparent pressure-sensitive film and the electrode layer do not need to be aligned, which reduces the overall manufacturing difficulty of the sensor and is conducive to large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention is described in detail below with reference to the embodiments and accompanying drawings, wherein:

[0029] Figure 1 It is a structural schematic diagram of an embodiment of the present invention.

[0030] Figure 2 It is a partial arrangement structure diagram of the electrode layer of an embodiment of the present invention.

[0031] Figure 3 It is a partial arrangement structure diagram of the electrode layer of another embodiment of the present invention.

[0032] Figure 4 It is the pressure resistance test curve of different formulations of the present invention. DETAILED DESCRIPTION

[0033] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0034] Thus, a feature indicated in this specification will be used to illustrate one of the features of an embodiment of the present invention, rather than implying that each embodiment of the present invention must have the described feature. In addition, it should be noted that this specification describes many features. Although some features can be combined together to illustrate possible system designs, these features can also be used in other combinations that are not explicitly described. Thus, unless otherwise stated, the described combinations are not intended to be limiting.

[0035] The principle of the present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0036] like Figure 1 As shown, the structure of the transparent pressure sensor of the present invention is very simple, and the main structure has two layers, one layer is a transparent pressure-sensitive film 1, and the other layer is an electrode layer 2 under the transparent pressure-sensitive film. The main part of the electrode layer 2 is a plurality of evenly arranged detection points. Each detection point can be connected to the positive electrode 21 and the negative electrode 22 of the detection point by pressing the transparent pressure-sensitive film, so that the corresponding resistance change can be detected at the conductive detection point. From another perspective, the voltage or current change can be detected at the conductive detection point, that is, the change of the electrical parameters of the detection point. The electrical parameters include any one of the resistance, voltage, and current of the detection point or a combination thereof. By analyzing the changes in the electrical parameters of each detection point, the pressure on the current detection point can be obtained, so that the pressure distribution of the transparent pressure sensor can be detected.

[0037] The positive electrode and negative electrode of each detection point are provided with a non-contacting joint part. The shape and structure of the joint parts of the positive electrode and the negative electrode are the same and complementary. The positive electrode and the negative electrode of each detection point are arranged relative to each other and have a certain interval between each other. When the transparent pressure-sensitive film is not subjected to external pressure, there is no conduction between the positive electrode and the negative electrode of the detection point. It can also be said that the resistance between them is also very large. When the transparent pressure-sensitive film is subjected to external pressure toward the electrode layer, the detection point subjected to pressure will be conducted through the transparent pressure-sensitive film, and the corresponding change in the detection value of the electrical parameter will be generated at each detection point. The current direction of the detection point is almost the horizontal current direction.

[0038] like Figure 2 , Figure 3 As shown, in a specific embodiment of the present invention, the positive electrode and the negative electrode of each detection point have electrode pins that are staggered with each other. The electrode pins can be parallel to each other, or they can be complementary in shape and not staggered with each other. The joints on the opposite sides of the positive electrode and the negative electrode of each detection point are in a comb-tooth shape, and the comb-tooth-shaped joints of the positive electrode and the negative electrode are plugged into each other and maintain a certain gap. Figure 2 Four detection points are shown. Figure 3 Twelve detection points are shown, and finally the lead wires of the positive electrodes and negative electrodes of the 12 detection points are routed parallel to each other and finally merge into a row at the bottom.

[0039] In other embodiments, the positive electrode and the negative electrode may also be in a spiral shape, such as a structure similar to that of a mosquito coil, and the positive electrode and the negative electrode may also be plugged into each other in a complementary manner.

[0040] In a specific embodiment, the detection points of the present invention are arranged in an array. When the transparent pressure sensor itself is a circle, the detection points can be evenly arranged around the center of the transparent pressure sensor, and the specific arrangement can be designed according to needs.

[0041] The transparent pressure-sensitive film of the present invention is made by mixing water-based resin, nano silver powder, nano hollow titanium dioxide, stabilizer, dispersant, defoamer and solvent. The electrode layer is made by etching ITO film or ITO glass.

[0042] The specific method for making the transparent pressure-sensitive film is introduced below.

[0043] First, nano silver powder is prepared. The nano silver powder can be purchased directly or prepared by the following method of the present invention.

[0044] Take the ratio of making nano silver powder in the laboratory as an example. Add 500 ml of silver nitrate alcohol aqueous solution into a beaker, and add 50 ml of concentrated ammonia water at a stirring speed of 100 rpm and a drop rate of 0.2 g / L·s to prepare a silver-ammine complex system.

[0045] Add ascorbic acid aqueous solution, polyvinyl pyrrolidone and methanol into a tripod flask to prepare a mixed solution. Add silver amino alcohol aqueous solution into the tripod flask at a rate of 0.5 g / L·s while stirring at a stirring speed of 500 rpm.

[0046] The tripod flask was placed in a 5°C chilled water solution.

[0047] After the reaction is completed, the silver-ammine complex system is centrifuged to collect the nano silver powder, and the nano silver powder is dried and solidified to obtain the nano silver powder.

[0048] Nano silver powder is added to a polyvinyl butyral (PVB) resin alcohol solution, and a dispersant, a defoamer, a leveling agent, a wetting agent, and hollow titanium dioxide with a particle size that meets a preset range (for example, hollow titanium dioxide with a particle size of 500 nanometers) are added, and an ultrasonic device is used for stirring to obtain a uniform mixed slurry. The weight percentage of raw materials used to prepare the mixed slurry is: 84-91% of the polyvinyl butyral (PVB) resin alcohol solution, 0.5-5% of the nano silver powder, 1-2% of the nano hollow titanium dioxide, 5% of the defoamer, 2-3% of the leveling agent, and 0.5-1% of the wetting agent.

[0049] The preset range of the particle size of the hollow titanium dioxide is mainly considered from two aspects. First, the hollow titanium dioxide particles need to have a scattering rate that meets the requirements for light. Second, according to the different pressure-sensitive properties required by the product, the hollow titanium dioxide particles need to meet the corresponding pressure-sensitive properties. Those skilled in the art can consider or detect whether the particle size of the hollow titanium dioxide meets the preset range from these two aspects.

[0050] The mixed slurry flows from the material trough onto the base belt, and a green film is formed through the relative movement of the base belt and the scraper. The thickness of the green film is controlled by the scraper at 0.6-1.0 mm.

[0051] The blank film and the base tape are sent to the drying room for drying in three stages, with the first stage at 35°C, the second stage at 45°C, and the third stage at 65°C. After the solvent evaporates, a transparent film is formed on the base tape, and the transparent film and the base tape together form a transparent pressure-sensitive film.

[0052] According to the structural requirements of the positive and negative electrodes, the ITO film or ITO glass is etched with an acidic solution to obtain an electrode layer.

[0053] Finally, the transparent pressure-sensitive film and the etched electrode layer are bonded together.

[0054] The transparent pressure sensor is obtained by punching out the electrode with the transparent pressure-sensitive film attached thereto using a prefabricated die.

[0055] The present invention does not limit the manufacturing process of the transparent pressure-sensitive film. In addition to the casting method, other film-forming processes can be selected. When the present invention makes a uniform slurry, due to the addition of a wetting agent, the wetting effect of the nano silver powder and the resin is better. After the film is formed, when the light enters the transparent pressure-sensitive film, the light can propagate around the constituent particles of the transparent pressure-sensitive film, thereby improving the light transmittance.

[0056] The following table shows three groups of formulations of the homogeneous slurry of the present invention.

[0057]

[0058] Table 1 Three formulation examples

[0059] The transparent pressure sensor made of the mixed slurry configured with the above three recipes was tested for visible light transmittance and 1-30N pressure resistance.

[0060] The visible light transmittance of formula 1-3 is shown in Table 2 below.

[0061] Visible light transmittance Recipe 1 91.3％ Recipe 2 86.1％ Recipe 3 95.6％

[0062] Table 2 Transmittance of different formulations

[0063] The pressure resistance test results of formula 1-3 are shown in Table 3 below. Figure 4The resistance characteristic curves of the transparent pressure sensors made of formulas 1-3 at 1-30N are shown. By comparing formulas 1-3, it can be seen that the significant difference between them is that the weight ratio of the nano silver powder is quite different. It can be seen that the configuration of the nano silver powder and other components according to the weight ratio of formula 1 can achieve the best balance between visible light transmittance and pressure, while ensuring the transparent characteristics of the transparent pressure sensor, and better retaining the pressure sensing characteristics of the pressure sensor.

[0064] Pressure, N Recipe 1, resistance, kΩ Recipe 2, resistance, kΩ Recipe 3, resistance, kΩ 1 848.775 83.333 1377.768 2 491.294 57.810 931.573 3 363.731 42.557 739.587 4 290.857 36.868 598.199 5 236.155 33.314 531.516 10 121.331 24.054 340.942 15 93.215 16.089 263.956 20 72.745 14.138 225.717 25 61.805 11.629 191.580 30 50.814 10.649 163.836

[0065] Table 3 Pressure resistance test results of different formulations

[0066] After the transparent pressure sensor is manufactured by the method of the present invention, the transparent pressure sensor has a simple structure and fewer layers, so it is thinner and more transparent, and there are no processing difficulties such as positive and negative electrodes.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A transparent pressure sensor, characterized in that: include: An electrode layer, wherein the electrode layer comprises a plurality of detection points arranged evenly, wherein the positive electrode and the negative electrode of each detection point are provided with a splicing portion which does not contact each other, and the splicing portions of the positive electrode and the negative electrode have the same shape and structure and are complementary and plugged; A transparent pressure-sensitive film is arranged above the electrode layer. When the transparent pressure-sensitive film is not subjected to external pressure, there is no conduction between the positive electrode and the negative electrode of the detection point. When the transparent pressure-sensitive film is subjected to external pressure toward the electrode layer, at least one detection point of the electrode layer is connected, and the detection point subjected to pressure is connected through the transparent pressure-sensitive film, and a change in the detection value of the corresponding electrical parameter is generated at each detection point; the transparent pressure-sensitive film does not need to be patterned and is made by the following steps: The mixed slurry flows from the material tank to the base belt, and the base belt and the scraper form a green film through the relative movement. The thickness of the green film is controlled by the scraper at 0.6~1.0mm; The blank film and the base tape are sent to the drying room for drying. After the solvent evaporates, a transparent film is formed on the base tape. The transparent film and the base tape together form a transparent pressure-sensitive film. The mixed slurry is prepared by the following steps: adding nano silver powder into polyvinyl butyral resin alcohol solution; Add dispersant, defoamer, leveling agent, wetting agent and nano hollow titanium dioxide with a particle size that meets a preset range; Ultrasonic stirring is used to obtain a uniform mixed slurry. The weight percentage of raw materials used to prepare the mixed slurry is: 84-91% polyvinyl butyral resin alcohol solution, 0.5-5% nano silver powder, 1-2% nano hollow titanium dioxide, 5% defoamer, 2-3% leveling agent, and 0.5-1% wetting agent.

2. The transparent pressure sensor according to claim 1, characterized in that: The splicing portion is in a comb-teeth shape or a spiral shape.

3. The transparent pressure sensor according to claim 2, characterized in that: When the splicing portion is in a comb-teeth shape, the comb teeth of the splicing portion are straight lines or curves.

4. The transparent pressure sensor according to any one of claims 1 to 3, characterized in that: The detection points are arranged in an array.

5. The transparent pressure sensor according to any one of claims 1 to 3, characterized in that: The electrical parameter includes one or a combination of resistance, voltage, and current between the positive electrode and the negative electrode at the detection point.

6. The transparent pressure sensor according to any one of claims 1 to 3, characterized in that: The electrode layer is formed by etching an ITO film or an ITO glass.

7. A method for manufacturing a transparent pressure sensor according to any one of claims 1 to 6, characterized in that: Includes steps: Adding nano silver powder to the polymer material solution to form a mixed slurry and stirring evenly; The mixed slurry is made into a transparent pressure-sensitive film; Etching the ITO film or ITO glass to form an electrode layer; Bonding the transparent pressure-sensitive film and the electrode layer; The electrode layer of the bonded transparent pressure-sensitive film is punched out to obtain a transparent pressure sensor.

8. The method for manufacturing the transparent pressure sensor according to claim 7, characterized in that: The mixed slurry is made into a transparent pressure-sensitive film, including: forming the mixed slurry into a film on a base belt, and performing multi-stage drying, wherein the drying temperature of each stage is higher than the drying temperature of the previous stage, to form a transparent pressure-sensitive film.

9. The method for manufacturing a transparent pressure sensor according to claim 7, characterized in that: The weight percentage of raw materials used to prepare the mixed slurry is: 90% polyvinyl butyral resin alcohol solution, 1.5% nano silver powder, 1% nano hollow titanium dioxide, 5% defoamer, 2% leveling agent, and 0.5% wetting agent.

10. A switch, characterized in that: Comprising the transparent pressure sensor as claimed in any one of claims 1 to 6.

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