CN116818152A - Pressure sensor, preparation method, data acquisition system and method - Google Patents

Abstract

The invention discloses a pressure sensor, a preparation method, a data acquisition system and a data acquisition method, wherein the cylindrical array type flexible pressure sensor comprises an ion gel dielectric layer, a plurality of columns of electrodes are arranged on the upper surface of the ion gel dielectric layer, a plurality of rows of electrodes are arranged on the lower surface of the ion gel dielectric layer, wherein a single sensor unit is formed at the crossing position of each row of electrodes and each column of electrodes.

Description

Pressure sensor, preparation method and data acquisition system and method

Technical field

The invention belongs to the field of sensor technology and relates to a pressure sensor, a preparation method, a data acquisition system and a method.

Background technique

In traditional medical diagnosis, doctors often perform medical diagnosis on patients by touching their tissues with their hands, which greatly improves the efficiency of diagnosis. However, during digestive endoscopy diagnosis and treatment, doctors cannot directly touch the patient's tissues, and the existing endoscopic visual feedback technology cannot accurately identify the location and size of the lesion area. When doctors use digestive endoscopes in the absence of force feedback, they may easily cause additional damage to the patient's digestive tract tissue.

Touch is an important function for humans to perceive and obtain external information through the skin, an important organ. Through tactile perception, humans can identify the shape, hardness, surface roughness, temperature and other information of the objects in contact, thereby obtaining a more detailed and rich sensory experience. In order to imitate the tactile sensing ability of human skin, various types of pressure sensors that can convert external stimuli into electronic signals to sense and quantify external stimuli have been proposed.

At present, according to different working principles, flexible pressure sensors can be divided into piezoresistive, piezoelectric, triboelectric, and capacitive types. Among these four types of sensors, capacitive flexible pressure sensors have been widely studied due to their advantages of simple structure, fast response speed, and low power consumption. Capacitive flexible pressure sensors can be divided into traditional capacitive pressure sensors and iono-electric capacitive pressure sensors according to different dielectric layers. For traditional capacitive pressure sensors, their sensitivity is often limited by the incompressibility and low dielectric constant of the elastomer; in addition, the capacitance change of traditional capacitive pressure sensors is easily affected by parasitic capacitance and environmental noise, which limits its Application in practical scenarios. The iono-electric pressure sensor uses ion gel as the dielectric layer of the sensor, forming a double electric layer capacitance at the interface between the electrode and the dielectric layer, which significantly improves the sensitivity of the sensor. Compared with other types of sensors, iono-electric pressure sensors have excellent sensing performance and can meet the needs for pressure sensing in a variety of application scenarios. In addition, studies have shown that the introduction of microstructures into iono-electric pressure sensors can further improve the sensor's sensing performance.

Digestive endoscopy is currently one of the most effective and reliable ways to treat digestive system diseases. It can observe abnormal lesions in the digestive tract through accurate and intuitive visual feedback, thereby providing doctors with more accurate diagnostic results. In traditional medical diagnosis, doctors often perform medical diagnosis on patients by touching their tissues with their hands, which greatly improves the efficiency of diagnosis. However, during digestive endoscopy diagnosis and treatment, doctors cannot directly touch the patient's tissues, and the existing endoscopic visual feedback technology cannot accurately identify the location and size of the lesion area. When doctors use digestive endoscopes in the absence of force feedback, they may easily cause additional damage to the patient's digestive tract tissue.

During the diagnosis and treatment of digestive endoscopy, the doctor extends the endoscope into the patient's body through the natural orifice, and performs diagnosis and surgical operations through the images fed back by the endoscope. This plays an important role in locating and treating the diseased areas in the body. However, the doctor Using a digestive endoscope in the absence of force feedback can easily cause damage to the patient's digestive tract tissue. At present, common flexible pressure sensors mainly include piezoresistive, piezoelectric, triboelectric, and capacitive types.

To sum up, the following problems still exist:

Lack of tactile information in digestive endoscopy. During the diagnosis and treatment of digestive endoscopy, doctors cannot directly touch the patient's tissues, and visual feedback cannot accurately identify the location and size of the diseased area. In addition, doctors performing surgery without force feedback may cause damage to normal tissues. , and even damage vital organs.

Sensor Disadvantages. Piezoresistive pressure sensors are susceptible to external influences, and signal drift may occur after long-term use; piezoelectric pressure sensors cannot measure static pressure; triboelectric pressure sensors are susceptible to external influences, and cannot measure static pressure; traditional capacitive sensors are dielectric The layer is incompressible, has the problem of low sensitivity, is susceptible to the influence of parasitic capacitance and the environment, and has poor measurement accuracy.

Contents of the invention

The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a pressure sensor, a preparation method and a data acquisition system and method. The sensor and method can solve the problem of lack of tactile information in the current digestive endoscopy diagnosis and treatment process, and have Features of high sensitivity and accurate measurement.

In order to achieve the above object, in the first aspect, the present invention discloses a cylindrical array type flexible pressure sensor, which includes an ion gel dielectric layer. The upper surface of the ion gel dielectric layer is provided with several rows of electrodes. The ion gel dielectric layer A number of row electrodes are provided on the lower surface of the glue dielectric layer, wherein the intersection positions of each row electrode and each column electrode form a single sensor unit.

The surface of the ion gel dielectric layer is provided with several pyramidal microstructures.

In a second aspect, the invention discloses a method for preparing a cylindrical array flexible pressure sensor, which includes the following steps:

1) Using polydimethylsiloxane film as the base material, apply stretched silver paste on the PDMS film to prepare row electrodes and column electrodes;

2) Prepare an ion gel dielectric layer with microstructure;

3) Use the ion gel dielectric layer, each row electrode and each column electrode to make a cylindrical array type flexible pressure sensor.

The specific operations of step 1) are:

11) Mix the PDMS prepolymer and the curing agent, stir and remove bubbles to obtain a PDMS mixture, spin-coat the PDMS mixture on a substrate sprayed with a release agent, and form a PDMS film after curing;

12) Place the mask with the electrode pattern on the PDMS film prepared in step 11) so that the PDMS film and the mask fit together, and then apply the stretched silver paste evenly on the PDMS film with the mask and solidify. Then take out the mask and cut it to obtain row electrodes and column electrodes.

In step 11), the mass ratio of PDMS prepolymer to curing agent is (10-12):1.

In step 2), a solution spin coating method is used to prepare an ion gel dielectric layer with a microstructure.

In a third aspect, the invention discloses a method for preparing a cylindrical array flexible pressure sensor, which includes the following steps:

The column electrodes, the ion gel dielectric layer and the row electrodes are wound and fixed on the digestive endoscope in sequence, so that the cylindrical array flexible pressure sensor is integrated on the digestive endoscope.

In a fourth aspect, the present invention discloses a data acquisition system, including a microcontroller module, a capacitance measurement module, a row and column scanning module, and a cylindrical array flexible pressure sensor. The cylindrical array flexible pressure sensor is integrated in a digestive endoscope. On the top, the cylindrical array flexible pressure sensor is grounded through the row and column scanning module, the cylindrical array flexible pressure sensor is connected to the capacitance measurement module, and the microcontroller module is connected to the output end of the capacitance measurement module and the control end of the row and column scanning module.

The microcontroller module is connected to a host computer, and the host computer can display the sensor data output by the microcontroller module.

In a fifth aspect, the present invention discloses a data collection method, which includes the following steps:

Obtain the capacitance information of each row of sensor units in the cylindrical array flexible pressure sensor detected by the capacitance measurement module;

The obtained capacitance information of each row of sensor units in the cylindrical array flexible pressure sensor is graphically displayed.

The obtained capacitance information of each sensor unit in the cylindrical array flexible pressure sensor is graphically displayed.

The invention has the following beneficial effects:

In specific operations, the pressure sensor, preparation method, data acquisition system and method of the present invention use PDMS as a flexible substrate, and at the same time, several columns of electrodes are provided on the upper surface of the ion gel dielectric layer. Several row electrodes are provided on the lower surface of the sensor, thereby forming a single sensor unit at the intersection of each row electrode and each column electrode. During measurement, each sensor unit arranged in an array is used for detection. The measurement accuracy is high, the sensitivity is high, and it can It allows doctors to obtain richer and more detailed tactile information during the operation, thereby improving the efficiency and safety of disease diagnosis and surgical treatment. It is also equipped with a corresponding data acquisition system, and uses the capacitance measurement module and the row and column scanning module to cooperate with each other. Acquire the capacitance information of the sensor unit to improve the accuracy and reliability of data collection.

Description of the drawings

Figure 1 is a structural diagram of the sensor according to the present invention;

Figure 2a is a structural diagram of a row electrode;

Figure 2b is a structural diagram of the column electrode;

Figure 3 is a structural diagram of the ion gel dielectric layer;

Figure 4 is a structural diagram of the data acquisition system according to the present invention;

Figure 5 is a physical diagram of the electrode prepared in Example 1;

Figure 6a is a structural diagram of the electrode in a planar state under a microscope;

Figure 6b is a structural diagram of the electrode in the cylindrical state under a microscope;

Figure 7 is a physical diagram of the ion-coagulated dielectric layer of the pyramid microstructure in Embodiment 1;

Figure 8 is a scanning electron microscope image of the pyramid microstructure ion gel dielectric layer in Example 1;

Figure 9 is a sensitivity test chart of the sensor described in Embodiment 1;

Figure 10 is a response time test chart of the sensor described in Embodiment 1;

Figure 11 is a cycle stability test chart of the sensor described in Embodiment 1;

Figure 12a is a test result diagram of the application of the sensor described in Embodiment 1 in tactile sensing of the digestive tract;

Figure 12b is another test result diagram of the application of the sensor described in Embodiment 1 in tactile sensing of the digestive tract;

Figure 12c is another test result diagram of the application of the sensor described in Embodiment 1 in tactile sensing of the digestive tract.

Among them, 1 is the column electrode, 2 is the ion gel dielectric layer, 3 is the row electrode, and 4 is the sensor unit.

Detailed ways

In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only These are part of the embodiments of the present invention, not all of them, and are not intended to limit the scope of the disclosure of the present invention. Furthermore, in the following description, descriptions of well-known structures and techniques are omitted to avoid unnecessarily obscuring the concepts disclosed in the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts should fall within the scope of protection of the present invention.

A schematic structural diagram according to a disclosed embodiment of the present invention is shown in the accompanying drawings. The drawings are not drawn to scale, with certain details exaggerated and may have been omitted for purposes of clarity. The shapes of the various regions and layers shown in the figures and the relative sizes and positional relationships between them are only exemplary. In practice, there may be deviations due to manufacturing tolerances or technical limitations, and those skilled in the art will base their judgment on actual situations. Additional regions/layers with different shapes, sizes, and relative positions can be designed as needed.

Embodiment 1

Referring to Figure 1, the cylindrical array flexible pressure sensor of the present invention is used in the process of endoscopic diagnosis and treatment and is installed on the digestive endoscope. The cylindrical array flexible pressure sensor includes an ion gel dielectric layer 2, The upper surface of the ion gel dielectric layer 2 is provided with a plurality of column electrodes 1, and the lower surface of the ion gel dielectric layer 2 is provided with a plurality of row electrodes 3, wherein the intersection positions of each row electrode 3 and each column electrode 1 form a Single sensor unit 4.

During operation, when pressure acts on the cylindrical array flexible pressure sensor of the present invention, the capacitance of the sensor unit 4 changes, thereby achieving pressure measurement.

Specifically, the cylindrical array flexible pressure sensor described in this embodiment includes three rows of electrodes 3 and eight columns of electrodes 1 to form 24 sensor units 4.

Referring to Figure 2a and Figure 2b, in actual application, the diameter of the colonoscope is 11-14mm, the circumference of the colonoscope is 34.6-44mm, the area range of the single sensor unit 4 is 2.25-4m ² , and the sensors in the same row The units 4 are evenly distributed in the circumferential direction of the digestive endoscope, and the distance between adjacent sensor units 4 in the same column is 1 mm.

It should be noted that in the present invention, the sensor units 4 in the same row share the row electrode 3, and the sensor units 4 in the same column share the column electrode 1, so as to reduce the number of sensor connections and facilitate application.

Embodiment 2

In order to produce the cylindrical array flexible pressure sensor described in this embodiment, the present invention discloses a preparation method of the cylindrical array flexible pressure sensor, which includes:

1) Production of flexible electrodes;

Using polydimethylsiloxane (PDMS) film as the base material, the stretched silver paste is blade-coated on the PDMS film using the blade coating method to form a flexible electrode. The specific process is:

11) Mix the PDMS prepolymer and the curing agent at a mass ratio of (10-12):1, and then stir it with a mixer at a speed of 1500-2000 rpm for 1-3 minutes to mix evenly and remove bubbles to obtain a PDMS mixture; Spray a layer of silicone aerosol release agent on the glass piece, pour the PDMS mixture on the glass piece, and then spin-coat at 300-500rpm for 20-40s. Cure the glass piece at 80-90°C for 30min-1h to form PDMS film;

12) Use a laser cutting machine to cut a PET film with a thickness of 50um to form a mask of the required electrode pattern. Place the mask on the PDMS film prepared in step 11) so that the PDMS film and the mask fit together, and stretch the The silver paste is evenly spread on the PDMS film with a mask, cured at 90-100°C for 4-6 hours, the mask is removed, and then the PDMS film is cut to obtain row electrode 3 and column electrode 1;

13) Use copper wires, heat-curing silver paste or conductive silver glue to lead out the row electrode 3 and column electrode 1 of the cylindrical array flexible pressure sensor to facilitate subsequent testing. Among them, the high-temperature curing silver paste is cured at 90°C for 30min- 1h, cure the conductive silver glue at 60℃ for 1h-2h.

2) Preparing the ion gel dielectric layer 2;

The solution spin coating method is used to prepare the PVDF-HFP/IL ion gel dielectric layer 2 with a microstructure. The specific process is:

21) Mix PVDF-HFP and acetone at a mass ratio of 1:(7-9), and then stir at 60-70°C for 2-4 hours to fully melt PVDF-HFP to obtain a mixed solution;

22) Add ionic liquid to the mixed solution obtained in step 21), and continue stirring at room temperature for 1 hour, where the mass ratio of PVDF-HFP to ionic liquid is 1.5: (1-1.2);

23) Drop the solution obtained in step 22) onto the template with microstructure, spin-coat it at a speed of 300-500rpm for 15-30s, and then dry it in an oven at 60°C for 30min-1h. After peeling and cutting, you get Ion gel dielectric layer 2.

In this embodiment, the ionic liquid is 1-ethyl-3-methylimidazole-bistrifluoromethylsulfonimide salt ([EMIM][TFSI]).

In this embodiment, the microstructure template is a template with a pyramid microstructure formed using photolithography technology. The side length of the square of the pyramidal microstructure is 70 μm, the height is 50 μm, and the distance between the sides of the square is 40 μm. The observation results of the microstructure template under the microscope are shown in Figure 3.

Embodiment 3

The preparation method of the cylindrical array flexible pressure sensor of the present invention includes the following steps:

The column electrode 1, the ion gel dielectric layer 2 and the row electrode 3 are wound around the digestive endoscope in sequence and fixed with PI (polyimide) tape to form a cylindrical array flexible pressure sensor.

Embodiment 4

In order to realize the data collection of the cylindrical array type flexible pressure sensor, the present invention also discloses a data collection system. The data collection system includes a hardware collection circuit and a host computer.

In this embodiment, the hardware acquisition circuit includes a cylindrical array flexible pressure sensor, a microcontroller module, a capacitance measurement module and a row and column scanning module; the cylindrical array flexible pressure sensor is integrated on the digestive endoscope, and the cylindrical array flexible pressure sensor The array type flexible pressure sensor is grounded through the row and column scanning module, the cylindrical array type flexible pressure sensor is connected to the capacitance measurement module, and the microcontroller module is connected to the output end of the capacitance measurement module and the control end of the row and column scanning module.

In this embodiment, the microcontroller module uses an STM32 microcontroller. The STM32 microcontroller is a series of 32-bit microcontroller products launched by STMicroelectronics. It has high performance, low power consumption, multiple peripherals, and integrated Due to its high accuracy and ease of development, STM32F103C8T6 was chosen as the microcontroller for the hardware acquisition circuit.

In this embodiment, the capacitance measurement module uses the PCap01AD chip. The PCap01AD chip can be connected to the capacitance sensor through four connection methods: single sensor drift mode, single sensor grounding mode, differential sensor drift mode, and differential sensor grounding mode. In the case of a single sensor drift mode connection, the PCap01AD chip can connect up to 7 sensors. Since there are a large number of sensor units 4 in the present invention, two PCap01AD chips are selected and a single sensor grounding mode connection method is used for the cylindrical array. The capacitance of a flexible pressure sensor is measured. The PCap01AD chip communicates with the microcontroller module through SPI communication. High-speed data transmission can be achieved through SPI communication and supports full-duplex communication.

In this embodiment, the sensor units 4 in the same row share the row electrode 3, and the sensor units 4 in the same column share the column electrode 1. Therefore, the 24 sensor units 4 have a total of 11 wires. The number of wires can be effectively reduced through electrode sharing. In addition, the present invention uses two PCap01AD chips to measure the capacitance of 8 columns simultaneously. At this time, an analog switch is used to realize the gating of three rows, so that the measurement of capacitance data of the 3×8 cylindrical array type flexible pressure sensor can be completed. The present invention selects the high-speed analog switch TS5A3357 chip to realize the line scan of the sensor array. The working voltage of the high-speed analog switch TS5A3357 chip is 1.65-5.5V. Under the control of the STM32 microcontroller, the line scan of the sensor array is realized, thereby realizing the cylindrical Collection of capacitance data from array-type flexible pressure sensors.

In addition, in this embodiment, the STM32 microcontroller sends the collected sensor data to the host computer through the serial port for digital display and storage. Among them, the present invention uses the CH343 chip to realize high-speed transmission of sensor array capacitance data.

Embodiment 5

Correspondingly, the present invention discloses a data collection method, which includes the following steps:

1) Obtain the capacitance information of each row of sensor units 4 in the cylindrical array flexible pressure sensor detected by the capacitance measurement module;

2) The microcontroller module receives the capacitance information of each row of sensor units 4 in the cylindrical array flexible pressure sensor output by the capacitance measurement module, and then uses the host computer to measure the capacitance information of each row of sensor units 4 in the cylindrical array flexible pressure sensor. Graphical display is performed, in which the capacitance data of the cylindrical array flexible pressure sensor is displayed in the form of a three-dimensional histogram in the host computer, so that the distribution of pressure can be observed more intuitively. The sensor digital acquisition scheme is shown in Figure 4 shown.

Embodiment 6

The preparation method of the cylindrical array flexible pressure sensor described in this embodiment includes:

1) Production of flexible electrodes;

Using polydimethylsiloxane (PDMS) film as the base material, the stretched silver paste is blade-coated on the PDMS film using the blade coating method to form a flexible electrode. The specific process is:

11) Mix the PDMS prepolymer and the curing agent at a mass ratio of 11:1, and then stir it with a mixer at 1800 rpm for 2 minutes to mix evenly and remove bubbles to obtain a PDMS mixture; spray a layer of silica gel aerosol on the glass piece. Release agent, pour the PDMS mixture onto the glass piece, then spin-coat at 400 rpm for 30 seconds, and cure the glass piece at 85°C for 45 minutes to form a PDMS film;

12) Use a laser cutting machine to cut a PET film with a thickness of 50um to form a mask of the required electrode pattern. Place the mask on the PDMS film prepared in step 11) so that the PDMS film and the mask fit together, and stretch the The silver paste is evenly spread on the PDMS film with a mask, cured at 95°C for 5 hours, the mask is removed, and then the PDMS film is cut to obtain row electrode 3 and column electrode 1;

13) Use copper wires, heat-curing silver paste or conductive silver glue to lead out the row electrode 3 and column electrode 1 of the cylindrical array flexible pressure sensor to facilitate subsequent testing. Among them, the high-temperature curing silver paste is cured at 90°C for 40 minutes. Cure the conductive silver glue at 60℃ for 1.5h.

2) Preparing the ion gel dielectric layer 2;

The solution spin coating method is used to prepare the PVDF-HFP/IL ion gel dielectric layer 2 with a microstructure. The specific process is:

21) Mix PVDF-HFP and acetone at a mass ratio of 1:8, and then stir at 65°C for 3 hours to fully melt PVDF-HFP to obtain a mixed solution;

22) Add ionic liquid to the mixed solution obtained in step 21), and continue stirring at room temperature for 1 hour, where the mass ratio of PVDF-HFP to ionic liquid is 1.5:1.2;

23) Drop the solution obtained in step 22) onto the template with a microstructure, spin-coat it at a speed of 400 rpm for 25 seconds, and then dry it in an oven at 60°C for 45 minutes. After peeling off and cutting, the ion gel dielectric layer is obtained. 2.

Embodiment 7

The preparation method of the cylindrical array flexible pressure sensor described in this embodiment includes:

1) Production of flexible electrodes;

Using polydimethylsiloxane (PDMS) film as the base material, the stretched silver paste is blade-coated on the PDMS film using the blade coating method to form a flexible electrode. The specific process is:

11) Mix the PDMS prepolymer and the curing agent at a mass ratio of 10:1, and then stir it with a mixer at a speed of 1500 rpm for 1 minute to mix evenly and remove bubbles to obtain a PDMS mixture; spray a layer of silica gel aerosol on the glass piece. Release agent, pour the PDMS mixture onto the glass piece, then spin-coat at 300 rpm for 20 seconds, and cure the glass piece at 90°C for 30 minutes to form a PDMS film;

12) Use a laser cutting machine to cut a PET film with a thickness of 50um to form a mask of the required electrode pattern. Place the mask on the PDMS film prepared in step 11) so that the PDMS film and the mask fit together, and stretch the The silver paste is evenly spread on the PDMS film with a mask, cured at 90°C for 4 hours, the mask is removed, and then the PDMS film is cut to obtain row electrode 3 and column electrode 1;

13) Use copper wires, heat-curing silver paste or conductive silver glue to lead out the row electrode 3 and column electrode 1 of the cylindrical array flexible pressure sensor to facilitate subsequent testing. Among them, the high-temperature curing silver paste is cured at 90°C for 30 minutes. Cure the conductive silver glue at 60°C for 1 hour.

2) Preparing the ion gel dielectric layer 2;

The solution spin coating method is used to prepare the PVDF-HFP/IL ion gel dielectric layer 2 with a microstructure. The specific process is:

21) Mix PVDF-HFP and acetone at a mass ratio of 1:7, and then stir at 60°C for 2 hours to fully melt PVDF-HFP to obtain a mixed solution;

22) Add ionic liquid to the mixed solution obtained in step 21), and continue stirring at room temperature for 1 hour, where the mass ratio of PVDF-HFP to ionic liquid is 1.5:1.1;

23) Drop the solution obtained in step 22) onto the template with a microstructure, spin-coat it at a speed of 300 rpm for 15 seconds, and then dry it in an oven at 60°C for 30 minutes. After peeling off and cutting, the ion gel dielectric layer is obtained. 2.

Embodiment 8

The preparation method of the cylindrical array flexible pressure sensor described in this embodiment includes:

1) Production of flexible electrodes;

Using polydimethylsiloxane (PDMS) film as the base material, the stretched silver paste is blade-coated on the PDMS film using the blade coating method to form a flexible electrode. The specific process is:

11) Mix the PDMS prepolymer and the curing agent at a mass ratio of 12:1, and then stir it with a mixer at 2000 rpm for 3 minutes to mix evenly and remove bubbles to obtain a PDMS mixture; spray a layer of silica gel aerosol on the glass piece. Release agent, pour the PDMS mixture onto the glass piece, then spin-coat at 500 rpm for 40 seconds, and cure the glass piece at 90°C for 1 hour to form a PDMS film;

12) Use a laser cutting machine to cut a PET film with a thickness of 50um to form a mask of the required electrode pattern. Place the mask on the PDMS film prepared in step 11) so that the PDMS film and the mask fit together, and stretch the The silver paste is evenly spread on the PDMS film with a mask, cured at 100°C for 6 hours, the mask is removed, and then the PDMS film is cut to obtain row electrode 3 and column electrode 1;

13) Use copper wires, heat-curing silver paste or conductive silver glue to lead out the row electrode 3 and column electrode 1 of the cylindrical array flexible pressure sensor to facilitate subsequent testing. Among them, the high-temperature curing silver paste is cured at 90°C for 1 hour. Cure the conductive silver glue at 60°C for 2 hours.

2) Preparing the ion gel dielectric layer 2;

The solution spin coating method is used to prepare the PVDF-HFP/IL ion gel dielectric layer 2 with a microstructure. The specific process is:

21) Mix PVDF-HFP and acetone at a mass ratio of 1:9, and then stir at 70°C for 4 hours to fully melt PVDF-HFP to obtain a mixed solution;

22) Add ionic liquid to the mixed solution obtained in step 21), and continue stirring at room temperature for 1 hour, where the mass ratio of PVDF-HFP to ionic liquid is 1.5:1;

23) Drop the solution obtained in step 22) onto the template with a microstructure, then spin-coat at a speed of 500 rpm for 30 seconds, then dry in an oven at 60°C for 1 hour, peel and cut, and obtain the ion gel dielectric layer 2.

Embodiment 9

The sensor flexible electrode prepared in this experiment is a PDMS/silver paste flexible electrode, and the ion gel dielectric layer 2 is PVDF-HFP/1-ethyl-3-methylimidazole bistrifluoromethylsulfonimide with a pyramid microstructure. The dielectric layer of salt ([EMIM][TFSI]), the specific preparation process is:

1) Preparation of flexible electrodes;

11) Mix the prepolymer of polydimethylsiloxane (PDMS) and the curing agent at a mass ratio of 10:1, and then stir it in a mixer at a speed of 2000 rpm for 1 minute to stir evenly and remove bubbles to obtain The PDMS mixture was spin-coated on a glass sheet sprayed with a silicone release agent at a rotation speed of 500 rpm for 40 seconds, then placed in an oven at a temperature of 90°C and heated and cured for 30 minutes to obtain a PDMS film.

12) Electrode pattern mask preparation;

Use a laser cutting machine to cut the PET film and prepare a mask with the required electrode shape to obtain the mask.

13) Prepare flexible electrodes by scraping method;

Place the mask on the cured PDMS film, attach the mask to the PDMS film, drop the stretched silver paste on the mask, and then scrape it so that the silver paste is evenly coated on the PDMS film, and then Place it in an oven at 90°C, heat and cure for 4 hours, then remove the mask and use a knife to cut it to form the required electrode.

14) Wiring;

Connect the PDMS/silver paste flexible electrode to the conductive lead through conductive silver glue, then put it in an oven at 60°C, cure for 1 hour, then take it out, and then stick the polyimide tape on the conductive silver glue to prevent the wire from being damaged during use. It falls off to facilitate subsequent testing and application. Figure 5 shows the prepared electrode.

In the flat state, the resistance of a single row electrode 3 is 3Ω, and the resistance of a single column electrode 1 is 1.4Ω. In the bent state, the resistance of a single row electrode 3 is 4.4Ω, and the resistance of a single column electrode 1 is 2Ω.

Under a microscope, the electrodes in the planar state and the cylindrical state were observed respectively, and the observation results under the microscope were obtained as shown in Figure 6a and Figure 6b. Among them, Figure 6a shows the electrode in the planar state, and Figure 6b shows the columnar state. According to the observation results of the electrode in the surface state, the stretched silver paste is evenly and continuously spread on the PD MS film without breakage, ensuring the good conductivity of the electrode.

2) Preparation of pyramid microstructure dielectric layer;

21) Mix PVDF-HFP and acetone at a mass ratio of 1:7, stir at 65°C and 500 rpm for 2 hours to completely melt PVDF-HFP in acetone, and then add [EMIM][TFSI to the above mixed solution. ] Ionic liquid, PVDF-HFP: ionic liquid = 3:2, continue stirring at 500 rpm for 1 hour at room temperature to form a mixed solution of PVDF-HFP, acetone and ionic liquid;

22) Spin-coat the mixed solution obtained in step 21) on a silicon wafer with a pyramid microstructure at a rotation speed of 400 rpm for 20 seconds. After the solvent is completely evaporated, peel and cut it to form a 10 mm × 45 mm film. Figure 7 shows the prepared PVDF -HFP/IL ion gel dielectric layer 2. A scanning electron microscope was used to characterize the morphology of the ion gel dielectric layer 2 with pyramid microstructure, and the results are shown in Figure 8.

3) Sensor packaging;

The prepared electrode and the ion gel dielectric layer 2 are packaged on the digestive endoscope according to a sandwich structure to form a cylindrical array type flexible pressure sensor.

4) Performance test of cylindrical array flexible pressure sensor. The specific results are:

41) The sensitivity test results are shown in Figure 9. It can be seen from Figure 9 that the cylindrical array flexible pressure sensor exhibits a sensitivity of 0.39kPa ^-1 in the pressure range of 0-40kPa.

42) The response/time test results are shown in Figure 10. From Figure 10, it can be seen that the response/recovery time of the cylindrical array flexible pressure sensor is 46ms.

43) The cyclic stability test results are shown in Figure 11. It can be seen from Figure 11 that the capacitance signal of the cylindrical array flexible pressure sensor did not drift greatly under 1200 loading/unloading cycles, indicating that the cylindrical array flexible pressure sensor The pressure sensor has good stability.

44) Application of cylindrical array flexible pressure sensor in tactile sensing of the digestive tract. The cylindrical array flexible pressure sensor is integrated on a digestive endoscope and allowed to move in the intestinal model. During the movement, the The cylindrical array flexible pressure sensor will be in contact with the intestines and will be subject to pressure. The capacitance change data of this process is collected through a digital acquisition system. Figures 12a-12c show the different states of the digestive endoscope moving in the digestive tract. The results show that the The cylindrical array flexible pressure sensor has good tactile sensing capability.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that the present invention can still be modified. Modifications or equivalent substitutions may be made to the specific embodiments, and any modifications or equivalent substitutions that do not depart from the spirit and scope of the invention shall be covered by the scope of the claims of the invention.

Claims (10)

1. The cylindrical array type flexible pressure sensor is characterized by comprising an ionic gel dielectric layer (2), wherein a plurality of columns of electrodes (1) are arranged on the upper surface of the ionic gel dielectric layer (2), a plurality of rows of electrodes (3) are arranged on the lower surface of the ionic gel dielectric layer (2), and a single sensor unit (4) is formed at the crossing position of each row of electrodes (3) and each column of electrodes (1).

2. A cylindrical array flexible pressure sensor according to claim 1, characterized in that the surface of the ionogel dielectric layer (2) is provided with a number of pyramid microstructures.

3. A method of manufacturing a cylindrical array flexible pressure sensor as claimed in claim 1, comprising the steps of:

1) The method comprises the steps of (1) taking a polydimethylsiloxane film as a base material, and scraping and coating stretched silver paste on a PDMS film to prepare a row electrode (3) and a column electrode (1);

2) Preparing an ionic gel dielectric layer (2) with a microstructure;

3) And manufacturing the cylindrical array type flexible pressure sensor by using the ionic gel dielectric layer (2), each row electrode (3) and each column electrode (1).

4. The method for manufacturing a cylindrical array type flexible pressure sensor according to claim 3, wherein the specific operation of the step 1) is as follows:

11 Mixing PDMS prepolymer with a curing agent, stirring and removing bubbles to obtain a PDMS mixture, spin-coating the PDMS mixture on a substrate sprayed with a release agent, and curing to form a PDMS film;

12 Placing the mask plate with the electrode pattern on the PDMS film prepared in the step 11), attaching the PDMS film to the mask plate, uniformly scraping and coating the stretched silver paste on the PDMS film with the mask plate, taking out the mask plate after solidification, and cutting to obtain the row electrode (3) and the column electrode (1).

5. The method for manufacturing a cylindrical surface array type flexible pressure sensor according to claim 4, wherein in the step 11), the mass ratio of PDMS prepolymer to curing agent is (10-12): 1.

6. a method of manufacturing a cylindrical array flexible pressure sensor according to claim 3, characterized in that in step 2) a solution spin coating method is used to manufacture the ion gel dielectric layer (2) with microstructure.

7. A method of manufacturing a cylindrical array flexible pressure sensor as claimed in claim 1, comprising the steps of:

the column electrode (1), the ionic gel dielectric layer (2) and the row electrode (3) are sequentially wound and fixed on the digestion endoscope, so that the cylindrical surface array type flexible pressure sensor is integrated on the digestion endoscope.

8. The data acquisition system is characterized by comprising a microcontroller module, a capacitance measuring module, a line-column scanning module and the cylindrical array type flexible pressure sensor as claimed in claim 1, wherein the cylindrical array type flexible pressure sensor is integrated on a digestive endoscope, the cylindrical array type flexible pressure sensor is grounded through the line-column scanning module, the cylindrical array type flexible pressure sensor is connected with the capacitance measuring module, and the microcontroller module is connected with the output end of the capacitance measuring module and the control end of the line-column scanning module.

9. The pressure data detection system of claim 8, wherein the microcontroller module is connected to a host computer, and the host computer is capable of displaying sensor data output by the microcontroller module.

10. The data acquisition method is characterized by comprising the following steps of:

acquiring capacitance information of each row of sensor units (4) in the cylindrical array type flexible pressure sensor of claim 1, which is detected by a capacitance measurement module;

and graphically displaying the acquired capacitance information of each row of sensor units (4) in the cylindrical array type flexible pressure sensor.