CN113720503A - Large-area-array high-sensitivity flexible elastic pressure sensor and preparation method thereof - Google Patents
Large-area-array high-sensitivity flexible elastic pressure sensor and preparation method thereof Download PDFInfo
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- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
- G01L9/02—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of variations in ohmic resistance, e.g. of potentiometers, electric circuits therefor, e.g. bridges, amplifiers or signal conditioning
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Abstract
The invention discloses a large-area array high-sensitivity flexible elastic pressure sensor and a preparation method thereof, wherein the pressure sensor comprises a composite layer, and the composite layer comprises a substrate, a transition layer, a spacing layer, an electrode layer and a force-sensitive layer; the force-sensitive layer comprises a conformal graphene film and a micro-nano multi-level coating; the conformal graphene film is formed by spraying graphene microchip slurry on the substrate and the electrode layer for the first time; the micro-nano multi-level coating is formed by spraying low-conductivity composite slurry on the conformal graphene film for the second time. The preparation method comprises the steps of firstly printing a transition layer on a substrate, then printing an electrode layer on the transition layer, preparing a spacing layer, then spraying graphene microchip slurry on the substrate and the electrode layer to obtain a conformal graphene film, and finally spraying low-conductivity composite slurry on the film to form the micro-nano multi-level coating. The invention has the advantages of improving the sensitivity of the sensor, increasing the area of the array, being beneficial to the micro integration of array devices and leading the sensor to have good flexibility and stretchability.
Description
Technical Field
The invention relates to the technical field of flexible pressure sensing, in particular to a large-area array high-sensitivity flexible elastic pressure sensor and a preparation method thereof.
Background
The flexible pressure sensor is widely applied to the fields of intelligent manufacturing, intelligent medical treatment, education service and the like. The rapid development in the related art has made an urgent need for sensing technology of a high-performance flexible pressure sensor. High-precision flexible mechanical sensing technology represented by robot touch sensing, robot safety protection, wearable human health detection and automobile intelligent sensing is developed vigorously, has huge market prospect and becomes an important mark for measuring national comprehensive strength and international competitiveness. However, the high-end flexible pressure sensing array device in China seriously depends on import and is listed as one of neck clamping technologies which restrict industrial development in China.
In the technical field of flexible pressure sensing, parameters such as sensitivity, large-area array, flexible and elastic modularization and the like of a sensor are used as key indexes to form consensus. However, compared to mechanical receptors distributed in large numbers on human skin, electronic skin has far failed to achieve human tactile perception levels in terms of high sensitivity, large-area tactile perception, and flexible and elastic modularization. The root cause of the method is as follows: due to materials and manufacturing processes, the high sensitivity of the unit device is generally difficult to transfer to the large-area array device; the micro integration of the array device on the flexible elastic substrate is limited, and indexes such as array scale, area and the like need to be improved.
Patent CN201910128787.2 discloses a preparation method for lifting a flexible conductive composite film for a sensor and a flexible sensor, wherein the preparation method comprises the steps of respectively coating graphene dispersion liquid and carbon nanotube dispersion liquid on an organic silica gel mold with a salient point array to obtain conductive silica gel molds, and oppositely pressing one sides of the two conductive silica gel molds with the salient point array to enable the coated graphene dispersion liquid and the coated carbon nanotube dispersion liquid to be located between the two organic silica gel molds, so as to obtain the flexible conductive composite film. The sensor of the invention has high sensitivity and is easy to prepare, but has the defects of insufficient array area and insufficient stretchability and flexibility.
Disclosure of Invention
Aiming at the technical problems that a large area array, high sensitivity and flexibility are difficult to obtain in the flexible pressure sensor at the present stage, the invention provides a large area array high sensitivity flexible pressure sensor and a preparation method thereof.
The technical scheme of the invention is as follows:
the utility model provides a high sensitive gentle elasticity pressure sensor of large array, its includes two composite beds, and two composite bed structures are the same and counterpoint the laminating, wherein:
the composite layer comprises a substrate, a transition layer, a spacing layer, an electrode layer and a force sensitive layer; the electrode layer is a metal electrode, preferably a silver electrode; the force-sensitive layer comprises a conformal graphene film and a micro-nano multi-level coating; the conformal graphene film is formed by spraying graphene microchip slurry on the substrate and the electrode layer for the first time; the micro-nano multi-level coating is formed by spraying low-conductivity composite slurry on the conformal graphene film for the second time; the transition layer and the spacing layer are arranged on the substrate, the electrode layer is arranged on the transition layer, and the force-sensitive layer is arranged on the substrate and the electrode layer.
Further, the graphene nanoplatelets are wrapped on the electrode layer and the substrate in a conformal mode through first spraying of graphene nanoplatelet slurry to form a conformal graphene film, and are wrapped on the conformal graphene film through second spraying of low-conductivity composite slurry to induce rheological forming of micro-nano-scale conductive particles on the surface of the conformal graphene film, so that a three-dimensional conductive network on the surface of the fiber and a force-electricity coupling self-compensation structure are constructed. The self-compensation structure is deformed in a self-compensation mode when being pressed, the contact area and compressibility of the force sensitive layer can be effectively improved through the multi-stage self-compensation structure, and the device has the characteristics of wide range and high sensitivity, so that the micro-nano multi-stage self-compensation structure is constructed and further assembled into an upper micro-nano interlocking force sensitive interface and a lower micro-nano interlocking force sensitive interface, and the range and sensitivity of the sensor can be effectively improved.
Furthermore, the solid content of the graphene nanoplatelets in the graphene nanoplatelet slurry is 0.1-12 wt%, and the thickness of the conformal graphene film is 0.5-5 μm. The particle diameter of the graphene nanoplatelets is 1-20 mu m, and the number of the graphene nanoplatelets is 1-10，The surface resistance of the conformal graphene film is 100-200 k omega.
Further, the composite paste with low conductivity includes a carbon nanotube composite paste or a carbon black paste. The solid content of the carbon nano tube in the carbon nano tube composite slurry is 0.5-5 wt%, the carbon nano tube composite slurry comprises carbon nano tube slurry or carbon nano tube and carbon black composite slurry or carbon nano tube, carbon black and graphene composite slurry, the thickness of the micro-nano multi-stage coating is 30-100 mu m，The surface resistance of the micro-nano multi-level coating is 200k omega-1M omega. .
Further, the spraying process is one or more of air spraying, ultrasonic spraying and electrostatic spraying.
Furthermore, in order to improve the measuring range and the sensitivity of the sensor and avoid the short circuit of the upper electrode and the lower electrode under the action of pressure, the force sensitive layer also comprises a high-resistance coating, and the high-resistance coating is formed by spraying high-resistance composite slurry on the micro-nano multi-level coating for the third time. The high-resistance composite slurry comprises carbon nano tubes and/or carbon black, the thickness of the high-resistance coating is 1-5 mu M, and the surface resistance is 500k omega-2M omega; the force-sensitive conductive coatings formed by the first spraying, the second spraying and the third spraying constitute a resistance gradient force-sensitive layer.
Further, the substrate material is a flexible elastic material, preferably artificial leather fabric or natural leather or silicone rubber or polyurethane. The transition layer is a snakelike polyurethane transition layer formed by printing. The electrode layer is a stretchable array metal electrode with a snake-shaped or fractal structure, the thickness of the electrode layer is 5-8 mu m, and a snake-shaped silver paste electrode layer is preferred. The serpentine configuration enables the sensor to have better stretchability in use.
The force sensitive layer is an arrayed gradient force sensitive layer, and comprises force sensitive units. In the area of the force sensitive unit, the area of the electrode accounts for 2-10%.
The spacing layer is an annular insulating spacing layer, and the shape and the size of the annular spacing layer are consistent with the size of the hollow mask used in the first, second and third spraying, namely the outside of the force sensitive unit area is exposed. The spacing layer is made of polyurethane or epoxy resin or silicon rubber, the thickness of the spacing layer is 10-20 mu m, and the spacing layer is higher than the electrode layer and lower than the force sensitive layer.
Further, the graphene microchip composite slurry is dispersed by means of ultrasonic oscillation and the like before spraying, the ratio of the cross-sectional area of the opening of the thimble of the spray gun to be 0.2-0.5 is regulated and controlled during spraying of the graphene microchip composite slurry, the spraying air pressure is regulated to be 0.45-0.6MPa, so that large fog cones and highly uniform atomized liquid drops are obtained, a conformal graphene film is obtained on an electrode layer, and agglomeration of graphene microchips is avoided.
When the low-conductivity composite slurry and the high-resistance composite slurry are sprayed, the ratio of the cross-sectional area of the opening of the thimble of the spray gun to the cross-sectional area is regulated to be less than or equal to 0.15, the spraying air pressure is regulated to be less than or equal to 0.5MPa, so that convoluted liquid drops are formed, and a micro-nano multilevel stacking structure is formed on the surface of the conformal graphene.
Furthermore, the leather is artificial leather fabric or natural leather, and the leather substrate can enable the prepared sensor to have good flexibility and stretchability and simultaneously can not cause injuries such as infection and the like to the skin of a human body wearing the sensor.
Furthermore, electrodes on the silver paste electrode layer are arranged in parallel, and the parallel arrangement enables the electrodes not to be easily broken when in use and has good stretchability.
Furthermore, the force-sensitive units on the sensor form an array, and the array can be arranged periodically or in any non-periodic multi-unit arrangement, and has designability and cuttability. The array size was m × n, where m is 1,2,3 … 128, n is 1,2,3 … 128, and m × n > 4.
The invention also provides a preparation method of the large-area array high-sensitivity flexible elastic pressure sensor, which comprises the following steps:
respectively processing two pieces of leather;
preparing a transition layer on two pieces of leather, preferably preparing a snake-shaped polyurethane transition layer by a screen printing technology;
preparing an electrode layer on the transition layer, preferably preparing a serpentine metal array reading electrode layer on the serpentine polyurethane transition layer through screen printing;
preparing an annular insulating spacer layer on a substrate;
preparing graphene microchip slurry, low-conductivity composite slurry and high-resistance composite slurry;
firstly spraying graphene microchip slurry on the substrate and the array reading electrode layer to obtain a conformal graphene film, then drying, preferably processing a large-area precise mask for arrayed spraying by using a laser cutting machine before the first spraying, and then spraying the graphene microchip slurry in a mask alignment manner;
spraying the low-conductivity composite slurry on the conformal graphene film for the second time to form a micro-nano multistage coating, drying, processing a large-area array spraying precision mask by using a laser cutting machine before the optimized second spraying, and spraying the low-conductivity composite slurry on the mask in an aligned mode to obtain two micro-nano multistage force sensitive layers with the same structure;
and aligning, laminating and packaging the two micro-nano multistage force sensitive layers with the same structure by a flexible film aligning and laminating technology to prepare the interlocking type large area array sensor.
Wherein, the nitrogen low-temperature plasma is used for processing the two pieces of leather, so that the film forming uniformity of the water-based force-sensitive slurry and the silver paste can be improved.
The sensor can keep good stretchability in the using process due to the serpentine structure, and meanwhile compared with a PVC (polyvinyl chloride) foaming material, the polyurethane has better stability, chemical resistance, rebound resilience and mechanical property and smaller compression deformability, and is suitable for being used as a material of a transition layer in the sensor.
Further, the proportion of graphene nanoplatelets and the ultrasonic spraying process are regulated and controlled, so that uniform conformal film formation of graphene on the surface of the fiber is realized; the particle dispersibility of the slurry and the size of the ultrasonically atomized liquid drop are regulated and controlled, the rheological molding of the conformal graphene surface micro-nano conductive particles is induced, and a fiber surface three-dimensional conductive network and a force-electricity coupling self-compensation structure are constructed. The three-dimensional conductive network and the self-compensation structure on the surface of the fiber can generate self-compensation deformation when being pressed, and the measuring range and the sensitivity of the sensor can be effectively improved.
The preparation method of the multilevel structure is regulated and controlled, so that the adhesive force of the force-sensitive film is improved; the surface resistance range of the film is regulated and controlled, and the sensitivity and the measuring range of the interlocking device are improved.
The method comprises the following steps of dispersing graphene microchip composite slurry by means of ultrasonic oscillation and the like before first spraying, regulating and controlling the cross-sectional area ratio of an opening of a thimble of a spray gun to be 0.2-0.5 during first spraying, and regulating the spraying air pressure to be 0.45-0.6MPa so as to obtain a large fog cone and highly uniform atomized liquid drops, so that a conformal graphene film is obtained on an electrode layer, and agglomeration of graphene microchips is avoided. When the low-conductivity composite slurry and the high-resistance composite slurry are sprayed, the ratio of the cross-sectional area of the opening of the thimble of the spray gun to the cross-sectional area is regulated to be less than or equal to 0.15, the spraying air pressure is regulated to be less than or equal to 0.5MPa, so that convoluted liquid drops are formed, and a micro-nano multilevel stacking structure is formed on the surface of the conformal graphene.
Further, the spraying process is one or more of air spraying, ultrasonic spraying and electrostatic spraying.
Further, high-resistance composite slurry is sprayed on the micro-nano multi-coating layer for the third time to form a high-resistance coating layer, then drying is carried out, preferably, a laser cutting machine is used for processing a large-area array spraying precision mask before the third spraying, and then the high-resistance composite slurry is sprayed on the mask in an opposite position.
Furthermore, the hollowed mask contraposition spraying technology is adopted when the first, second and third spraying are carried out. When the hollowed-out mask is prepared, a laser cutting machine or a punching cutting machine is used for preparing arrayed hollowed-out holes on the PET film with the single-sided adhesive or the double-sided adhesive or the silica gel adhesive, and the size and the interval of the hollowed-out holes are consistent with the size and the interval of the designed force sensitive units.
The pressure imaging system prepared by the large-area array flexible elastic pressure sensor comprises a sensor, a row selector, a flexible adapter plate, a microprocessor, a wireless transmission module and a user interface, wherein the wireless transmission module is preferably a Bluetooth transmission module.
The interlocking piezoresistive sensor array adopts a row and column acquisition circuit, and adjacent unit devices have the problem of signal crosstalk, so that a zero potential scanning method is adopted, the voltage is sequentially applied to each row through a row selector, and the voltages of the rest rows are zero, so that the row and column signal crosstalk is greatly reduced, and the data reading speed is improved.
The flexible adapter plate is connected with the sensor and the microprocessor and is responsible for communication between the sensor and the microprocessor, control signals of the microprocessor are transmitted to the sensor, information collected by the sensor is transmitted to the microprocessor, and the flexible adapter plate can also ensure that the system keeps good flexibility when in use, and the problems of breakage and the like cannot occur.
The microprocessor controls the whole system and can perform A/D conversion and noise reduction on the signals output by the sensor.
The microprocessor processes signals transmitted by the sensor and transmits the signals to the user interface through the wireless transmission module, and the user interface can display the distribution imaging of the tactile pressure in real time according to different application scenes.
The invention has the advantages that:
the flexible elastic substrate such as artificial leather fabric substrate or natural leather substrate or silicon rubber or polyurethane can keep certain flexibility and stretchability when the sensor is used, and meanwhile, the damage such as infection and the like cannot be caused in the contact process with the skin of a human body. The secondary or multiple spraying technology is favorable for micro integration of array devices on the flexible elastic substrate, the area of the sensor array can be enlarged, a self-compensation structure is constructed, self-compensation deformation occurs when the self-compensation structure is pressed, and the measuring range and the sensitivity of the sensor can be effectively improved. The sensor prepared by the preparation process disclosed by the invention has the advantages of high sensitivity, tiny and convenient integration of array devices, large array area and good flexible and elastic tensile properties.
Drawings
FIG. 1 is a composite layer structure diagram of an embodiment of a large-area array high-sensitivity elastic pressure sensor according to the present invention.
FIG. 2 is a diagram illustrating the effect of a composite layer of an embodiment of the large-area array high-sensitivity elastic-flexible pressure sensor according to the present invention.
Fig. 3 is a flow chart of a manufacturing process of the large-area array high-sensitivity flexible elastic pressure sensor of the invention.
Fig. 4 is a signal crosstalk analysis diagram of an array circuit.
FIG. 5 is a schematic diagram of a zero potential scanning method of the array circuit.
Fig. 6 is a working schematic diagram of a low noise array acquisition circuit and a pressure imaging system of the large-area array high-sensitivity flexible elastic pressure sensor according to an embodiment.
Detailed Description
The present invention will be described in detail below with reference to the accompanying drawings.
The examples are given for the purpose of better illustration of the invention, but the invention is not limited to the examples. Therefore, those skilled in the art should make insubstantial modifications and adaptations to the embodiments of the present invention in light of the above teachings and remain within the scope of the invention.
Example 1
Referring to fig. 1, it is a composite layer structure diagram of a large-area array high-sensitivity flexible elastic pressure sensor according to the present invention. Specifically, the large-area array high-sensitivity flexible elastic pressure sensor of the present embodiment includes a first force-sensitive composite layer and a second force-sensitive composite layer.
In this embodiment, the first force-sensitive composite layer and the second force-sensitive composite layer have the same structure and are bonded in an aligned manner, wherein the composite layer includes a substrate, a transition layer, a spacer layer, an electrode layer and a force-sensitive layer, and the electrode layer is a silver electrode.
The force-sensitive layer comprises a conformal graphene film, a micro-nano multi-level coating and a high-resistance coating. The conformal graphene film is formed by spraying graphene microchip slurry on the substrate and the electrode layer for the first time, and the micro-nano multilevel coating is formed by spraying low-conductivity composite slurry on the conformal graphene film for the second time. The transition layer and the spacing layer are arranged on the substrate, the electrode layer is arranged on the transition layer, and the force-sensitive layer is arranged on the substrate and the electrode layer.
Preferably, the solid content of the graphene nanoplatelets in the graphene nanoplatelet slurry is 12% wt, and the thickness of the conformal graphene thin film is 5 μm. The particle size of the graphene nanoplatelets is 20 microns, the number of graphene nanoplatelets is 10, and the surface resistance is 100k omega.
Preferably, the composite slurry with low conductivity is carbon nanotube slurry, the solid content of carbon nanotubes in the carbon nanotube slurry is 5 wt%, the thickness of the formed micro-nano multilevel coating is 100 μm, and the surface resistance is 500k Ω.
Preferably, the high-resistance coating is formed by spraying high-resistance composite slurry on the micro-nano multi-level coating for the third time. The high-resistance composite slurry comprises carbon nano tubes, the thickness of the high-resistance coating is 5 mu M, and the surface resistance is 2M omega.
Preferably, the substrate is made of artificial leather fabric, because the artificial leather fabric has low cost, good flexibility and stretchability, and no harm such as infection to human skin during the use of the sensor.
Preferably, the electrode layer and the transition layer are respectively a serpentine silver paste electrode and a serpentine polyurethane, the electrodes on the electrode layer are arranged in parallel, and the thickness of the electrode layer is 5 μm. The sensor has the advantages that the sensor has stronger tensile property due to the snake-shaped structure, and meanwhile, compared with a PVC (polyvinyl chloride) foaming material, the polyurethane has better stability, chemical resistance, resilience and mechanical property and smaller compression deformability, so that the polyurethane is very suitable to be used as a material of a sensor transition layer in the invention.
Preferably, the force-sensitive layer is an arrayed gradient force-sensitive layer, and the force-sensitive layer comprises force-sensitive units. In the area of the force sensitive unit, the area of the electrode accounts for 2-10%.
Preferably, the spacing layer is an annular insulating spacing layer, and the shape and the size of the annular insulating spacing layer are consistent with the size of the hollow mask used in the first, second and third spraying, namely the outside of the force sensitive unit area is exposed. The spacing layer is made of polyurethane or epoxy resin or silicon rubber, the thickness of the spacing layer is 10-20 mu m, and the spacing layer is higher than the electrode layer and lower than the force sensitive layer.
Preferably, the graphene microchip slurry is dispersed in an ultrasonic oscillation mode before the first spraying; the ratio of the cross-sectional area of the opening of the thimble of the spray gun to the cross-sectional area is regulated to be 0.5 during the first spraying, the spraying air pressure is regulated to be 0.6MPa, so that a large fog cone and high-uniformity atomized liquid drops are obtained, a conformal graphene film is obtained on an electrode layer, and the agglomeration of graphene micro-sheets is avoided. When the low-conductivity composite slurry and the high-resistance composite slurry are sprayed, the ratio of the cross-sectional area of the opening of the thimble of the spray gun to the cross-sectional area is regulated to be 0.15, the spraying air pressure is regulated to be 0.5MPa, so that convoluted liquid drops are formed, and a micro-nano multilevel stacking structure is formed on the surface of the conformal graphene.
Preferably, the force sensitive elements on the sensor form an array, the array being periodically arranged, the array having a size of 128 x 128.
The sensor in the embodiment has good flexibility, stretchability and high sensitivity, and is convenient for micro integration of the array device.
Example 2
In order to more clearly illustrate the structure and the manufacturing method of the large-area array high-sensitivity flexible elastic pressure sensor of the present invention, the following is described in detail with reference to fig. 2 and 3. Referring to fig. 3, it is a flow chart of a manufacturing process of a large-area array high-sensitivity flexible elastic sensor of the present invention, specifically, it includes the steps of:
and S11, respectively processing the two leathers. In the embodiment, the nitrogen low-temperature plasma is used for treating the two artificial leather fabrics, so that the film forming uniformity of the aqueous force sensitive slurry and the silver paste can be improved.
S12, preparing the transition layer and the electrode layer on two pieces of leather by screen printing technique. Transition layer is snakelike polyurethane in this embodiment, and the electrode layer is snakelike silver thick liquid electrode, and snakelike structure can make the sensor have good stretchability when using.
And S13, processing the large-area arrayed spraying precision mask by using a laser cutting machine. The mask in this embodiment is a porous structure, and each hole is above a serpentine electrode.
And S14, dispersing the graphene microchip slurry in an ultrasonic oscillation mode.
S15, spraying the graphene microchip slurry on the electrode layer through mask ultrasonic contraposition spraying, realizing a conformal graphene film with uniform fiber surface, regulating and controlling the cross-sectional area of the opening of the thimble of the spray gun to be 0.5 during spraying, and adjusting the spraying air pressure to be 0.6MPa so as to obtain a large spray cone and highly uniform atomized liquid drops and avoid agglomeration of graphene microchips.
S16, spraying the carbon nanotube slurry on the conformal graphene film through mask ultrasonic contraposition spraying, adjusting the cross-sectional area ratio of an opening of a thimble of a spray gun to be 0.15 during spraying, adjusting the spraying air pressure to be 0.5MPa to form convoluted liquid drops, and forming a micro-nano secondary stacking structure on the surface of the conformal graphene so as to obtain a first force-sensitive composite layer and a second force-sensitive composite layer which are identical in structure.
And S17, aligning and laminating the first force-sensitive composite layer and the second force-sensitive composite layer based on a flexible film alignment and lamination technology, so as to realize the packaging and lamination of the interlocking large-area array device, and realize the reliable binding of the reading circuit electrode by adopting a flexible adapter plate.
FIG. 2 is a diagram showing the effect of the composite layer of the large-area array high-sensitivity flexible elastic pressure sensor prepared by the preparation method of the embodiment, wherein the composite layer is provided with a plurality of force-sensitive units, and the structures are connected through the serpentine electrodes.
Example 3
In this embodiment, the pressure imaging system is formed by using the large-area array flexible elastic pressure sensor obtained by the preparation method of the present invention and matching with other modules, and in order to more clearly illustrate the working principle and the structure of the system, the following detailed description is made with reference to fig. 4, fig. 5, and fig. 6.
Fig. 4 is a signal crosstalk analysis diagram of an array circuit, and as shown in the figure, signal crosstalk problems exist in adjacent unit devices. FIG. 5 is a schematic diagram of a zero potential scanning method of the array circuit, in which a row selector sequentially applies voltages to each row, and the voltages of the remaining rows are zero, so that row-column signal crosstalk is greatly reduced and the data reading speed is increased.
Fig. 6 is a working schematic diagram of a low noise array acquisition circuit and a pressure imaging system of a large-area array high-sensitivity flexible elastic pressure sensor according to this embodiment, as shown in the figure, an interlocking piezoresistive sensor array employs a row-column acquisition circuit, and adjacent unit devices have a signal crosstalk problem. As shown in fig. 6, in this embodiment, an array sensor signal acquisition and conditioning circuit module is further developed, which includes a flexible adapter board, a microprocessor, a wireless transmission module, and a user interface.
The flexible adapter plate is responsible for the communication between sensor and the microprocessor, on transmitting microprocessor's control signal to the sensor, transmit the information that the sensor was gathered to microprocessor again in to the flexible adapter plate also can ensure that the system keeps good flexibility when using, can not take place fracture scheduling problem.
The microprocessor controls the whole system and can perform A/D conversion and noise reduction on the signals output by the sensor.
The microprocessor processes signals transmitted by the sensor and transmits the signals to the user interface through the wireless transmission module, and the user interface can display the distribution imaging of the tactile pressure in real time according to different application scenes.
Finally, the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all of them should be covered in the claims of the present invention.
Claims (10)
1. The utility model provides a big high sensitive gentle elasticity pressure sensor of area array which characterized in that, includes the composite bed:
the composite layer comprises a substrate, a transition layer, a spacing layer, an electrode layer and a force-sensitive layer; the force-sensitive layer comprises a conformal graphene film and a micro-nano multi-level coating; the conformal graphene film is formed by spraying graphene microchip slurry on the substrate and the electrode layer for the first time; the micro-nano multilevel coating is formed by spraying low-conductivity composite slurry on the conformal graphene film for the second time; the transition layer, the spacing layer are on the substrate, the electrode layer is on the transition layer, and the force sensitive layer is on the substrate and the electrode layer.
2. The large-area array high-sensitivity flexible-elastic pressure sensor according to claim 1, wherein: the solid content of the graphene nanoplatelets in the graphene nanoplatelet slurry is 0.1-12% wt, and the thickness of the conformal graphene film is 0.5-5 μm; the particle size of the graphene nanoplatelets is 1-20 μm, the number of the graphene nanoplatelets is 1-10, and the surface resistance of the conformal graphene film is 100-200 k omega.
3. The large-area array high-sensitivity flexible-elastic pressure sensor according to claim 1, wherein: the composite slurry with low conductivity comprises carbon nanotube composite slurry or carbon black slurry, wherein the solid content of carbon nanotubes in the carbon nanotube composite slurry is 0.5-5 wt%; the carbon nanotube composite slurry comprises carbon nanotube slurry, or carbon nanotube and carbon black composite slurry, or carbon nanotube, carbon black and graphene composite slurry; the structure thickness of the micro-nano multi-level coating is 30-100 mu M, and the surface resistance of the micro-nano multi-level coating is 200k omega-1M omega.
4. The large-area array high-sensitivity flexible-elastic pressure sensor according to claim 1, wherein: the force sensitive layer further comprises a high-resistance coating, the high-resistance coating is formed by spraying high-resistance composite slurry on the micro-nano multi-level coating for the third time, the high-resistance composite slurry comprises carbon nano tubes and/or carbon black, the thickness of the high-resistance coating is 1-5 mu M, and the surface resistance is 500k omega-2M omega.
5. The large-area array high-sensitivity flexible-elastic pressure sensor according to claim 1, wherein: the substrate is made of a flexible elastic material; and/or the spacing layer is an annular insulating spacing layer, the spacing layer is made of polyurethane or epoxy resin or silicon rubber, the thickness of the spacing layer is 10-20 μm, and the spacing layer is higher than the electrode layer and lower than the force-sensitive layer; and/or the force-sensitive layer is an arrayed gradient force-sensitive layer, and the force-sensitive layer comprises force-sensitive units; and/or the transition layer is serpentine polyurethane; and/or the electrode layer is a stretchable array metal electrode with a snake-shaped or fractal structure, and the thickness of the electrode layer is 5-8 μm.
6. The large-area array high-sensitivity flexible-elastic pressure sensor according to claim 1, wherein: the graphene nanoplatelets slurry is dispersed by means of ultrasonic oscillation and the like before spraying.
7. The large-area array high-sensitivity flexible-elastic pressure sensor according to claim 1, wherein: regulating the ratio of the cross-sectional area of the opening of the thimble of the spray gun to 0.2-0.5 when the graphene microchip slurry is sprayed, and regulating the pressure of the spraying air to 0.45-0.6 MPa; and when the low-conductivity composite slurry and the high-resistance composite slurry are sprayed, the ratio of the cross-sectional area of the opening of the thimble of the spray gun to the cross-sectional area is regulated to be less than or equal to 0.15, and the spraying air pressure is regulated to be less than or equal to 0.5 MPa.
8. The method for preparing a large-area array high-sensitivity flexible elastic pressure sensor as claimed in any one of claims 1 to 7, wherein the method comprises the steps of:
(1) preparing a transition layer on the substrate;
(2) preparing an array readout electrode layer on the transition layer;
(3) preparing an annular insulating spacer layer on the substrate;
(4) spraying graphene microchip slurry on the substrate and the array readout electrode layer for the first time to obtain a conformal graphene film, and then drying;
(5) spraying low-conductivity composite slurry on the conformal graphene film for the second time to form a micro-nano multi-level coating structure, and then drying to obtain an arrayed gradient force-sensitive composite layer;
(6) and flexibly packaging the arrayed gradient force-sensitive composite layer.
9. The method for preparing a large-area array high-sensitivity flexible elastic pressure sensor according to claim 8, wherein the method comprises the following steps: dispersing the graphene microchip slurry before the first spraying; thirdly spraying high-resistance composite slurry on the micro-nano multi-level coating structure to form a high-resistance coating, and then drying; the spraying process is respectively regulated and controlled during the first spraying, the second spraying and the third spraying; and carrying out the first, second and third spraying by using a hollow mask for contraposition.
10. A pressure imaging system prepared using the sensor of claims 1-7, comprising a sensor, a row selector, a flexible adapter plate, a microprocessor, a wireless transmission module, and a user interface, wherein:
the row selector applies the voltage to each row of the row-column acquisition circuit in sequence and the rest of the voltage is zero; the flexible adapter plate is connected with the sensor and the microprocessor; the microprocessor controls the whole system and converts and reduces noise of the signal output by the sensor; the wireless transmission module transmits signals between the microprocessor and the user interface; the user interface displays the pressure distribution imaging in real time.
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