Preparation process and system of flexible electronic sensor based on liquid metal material

Abstract

The invention provides a preparation process and system of a flexible electronic sensor based on a liquid metal material, and relates to the technical field of electronics and sensors, and the preparation process of the flexible electronic sensor based on the liquid metal material comprises line drawing, line preparation, substrate treatment, line cutting and hot-pressing packaging. The system comprises a conversion device, a coating device, a circuit preparation device, a base material processing device, a circuit cutting device and a hot-pressing packaging device.

Description

Technical Field

[0001] The present invention relates to the fields of electronic technology and sensor technology, and in particular to a preparation process and system of a flexible electronic sensor based on liquid metal material. Background Art

[0002] With the rapid development of science and technology, flexible electronic sensors have shown great application potential in consumer electronics, medical health, smart home and other fields due to their unique flexibility and wearability. Among them, liquid metal materials have become an ideal choice for the preparation of high-performance flexible electronic sensors due to their excellent conductivity and deformability. This paper aims to review the latest research progress of flexible electronic sensors based on liquid metal materials, and explore their preparation process, technical challenges, market demand and future application prospects. Liquid metals, such as gallium-based alloys, have unique physical and chemical properties, such as high conductivity, low melting point and good fluidity. These properties give liquid metals unique advantages in the field of flexible electronics and enable the preparation of flexible sensors with excellent performance. However, the high surface tension and easy oxidation of liquid metals also bring challenges to their processing and application. The high surface tension of liquid metals makes it difficult to achieve precise patterning through traditional printing technology. In recent years, researchers have developed a variety of methods, such as microfluidics, laser etching and electrochemical deposition, to achieve precise patterning of liquid metals. However, these methods still have problems such as high cost and complex process. With the popularity of smart devices, flexible sensors are increasingly used in touch screens, wearable devices, and smart textiles. Liquid metal sensors have huge market potential in these fields due to their high sensitivity and good flexibility. In the field of medical health, flexible sensors are used to monitor physiological parameters such as heart rate, blood pressure, and body temperature, as well as to achieve remote medical care and health management. Liquid metal sensors have unique advantages in medical monitoring and health management due to their good fit with human skin and long-term stability. Smart home devices require sensors to have the characteristics of low power consumption, high sensitivity, and easy integration. Liquid metal sensors can meet these requirements and provide strong support for the intelligence and automation of smart homes. Therefore, it is of great significance to develop an efficient, safe, and economical preparation process and system of flexible electronic sensors based on liquid metal materials, and to bring more convenience and comfort to people's lives, improve the quality of life, and reduce medical costs by continuously optimizing the preparation process, reducing costs, and improving performance. Summary of the invention

[0003] The present invention provides a preparation process and system of a flexible electronic sensor based on liquid metal material, which is used to solve the problems raised in the above background technology.

[0004] In order to solve the above technical problems, the first aspect of the present invention discloses a preparation process of a flexible electronic sensor based on liquid metal material, comprising:

[0005] Step 1. Circuit preparation: laser processing is performed on the flexible substrate to form a laser-induced microstructure area and an area not processed by the laser, liquid metal is pumped into the microstructure area to form a liquid metal microchannel, a stretchable conductive wire is connected to both ends of the liquid metal microchannel, and the circuit substrate is obtained by drying and curing;

[0006] Step 2. Substrate treatment: cleaning and surface activation treatment of the circuit substrate, coating with a wetting agent to obtain a wet modified substrate.

[0007] Furthermore, it also includes:

[0008] Step 3. Circuit cutting: using a laser cutting machine to cut the wet modified substrate to obtain a cut piece;

[0009] Step 4. Hot-press packaging: hot-press packaging the cut parts with the adaptive elastic material.

[0010] Furthermore, the method further includes laminating the circuit after cutting, laminating a protective film material on the cut piece to obtain the cut piece after laminating, and performing hot pressing packaging.

[0011] Furthermore, the main component of the liquid metal is 80wt.% of gallium, the flexible substrate is polyimide (PI), polyethylene terephthalate (PET) or Ecoflex silicone, and the surface activation treatment includes covering the metal part with a mask and performing plasma treatment on the surrounding flexible packaging part.

[0012] Furthermore, the protective film material is polyurethane (PU), polyvinyl chloride (PVC) or biocompatible silicone.

[0013] Furthermore, the material of the stretchable conductive wire is a conductive polymer or a carbon nanotube.

[0014] The second aspect of the present invention discloses a preparation system for a flexible electronic sensor based on liquid metal materials, including a circuit preparation device and a substrate processing device. The circuit preparation device is used to form a laser-induced microstructure area and an area not processed by laser on a flexible substrate, pump liquid metal into the microstructure area to form a liquid metal microchannel, connect a stretchable conductive wire to both ends of the liquid metal microchannel, and dry and solidify to obtain a circuit substrate; the substrate processing device includes a substrate cleaning device, a plasma processing device and a wetting agent coating device, the substrate cleaning device is used to remove grease and dust; the plasma processing device is used to perform plasma treatment on the flexible packaging part without a mask; the wetting agent coating device is used to coat a layer of wetting agent on the surface-modified substrate to obtain a wet modified substrate.

[0015] Furthermore, it also includes a cutting device, which is used to cut the wet modified substrate to obtain cut pieces.

[0016] Furthermore, it also includes a packaging device, which is used to perform hot-pressing packaging on the cut pieces using the adaptive elastic material.

[0017] Furthermore, it also includes a film sticking device, which is used to stick the protective film material on the cut piece to obtain the cut piece after film sticking, and perform hot pressing packaging.

[0018] Compared with the prior art, the present invention provides a preparation process and system for a flexible electronic sensor based on liquid metal material, which has the following beneficial effects:

[0019] 1. Improve precision: Use laser and ultrasonic processing to ensure the accuracy and clarity of the circuit pattern.

[0020] 2. Control substrate treatment parameters: According to the material and properties of the substrate, select the surface activation treatment method and parameters to improve adhesion and conductivity.

[0021] 3. Optimize cutting process: adopt advanced cutting technology and equipment to improve cutting efficiency and accuracy and reduce waste and loss.

[0022] 4. Select protective film material: Select the protective film material according to application requirements to ensure the durability and biocompatibility of the electronic skin.

[0023] 5. Control hot pressing packaging parameters: Set the temperature and pressure parameters according to the material and performance of the electronic skin to ensure that the encapsulated electronic skin has good flexibility and conductivity.

[0024] 6. The product prepared in this application can be better applied to the angle correction and position calibration method of the humanoid robot. By obtaining the actual angle value of each joint of the robot and the actual position of the end effector in real time and comparing them with the theoretical value, the corresponding deviation is obtained. Then, the drive motors of each joint of the robot are regulated according to these deviations to achieve high-precision operation of the robot. This method is simple, fast and accurate, which significantly improves the operating accuracy and efficiency of the robot and meets various high-precision operation requirements.

[0025] 7. A new algorithm is used to achieve uniform distribution of liquid metal in the sensor, improving the stability and sensitivity of the sensor.

[0026] 8. Use high-precision laser beams and ultrasonic drive to achieve precise patterning in the preparation process at the micro-nano scale, reduce the use of molds, avoid the use of traditional technologies such as screen printing, gravure printing or inkjet printing, achieve micro-nano scale processing, improve resolution, increase pattern complexity, reduce material waste and environmental pollution, and improve performance and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 This is a flow chart of a preparation process of a flexible electronic sensor based on liquid metal material according to Example 1;

[0029] Figure 2 This is a flow chart of a preparation process of a flexible electronic sensor based on liquid metal material according to Example 2;

[0030] Figure 3 This is a flow chart of the preparation process of a flexible electronic sensor based on liquid metal material in Example 3. DETAILED DESCRIPTION

[0031] The preferred embodiments of the present invention are described below. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0032] In addition, in the present invention, the descriptions of "first" and "second" are only used for descriptive purposes, and do not specifically refer to the order or sequence, nor are they used to limit the present invention. They are only used to distinguish components or operations described with the same technical terms, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions and technical features between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0033] The following is a detailed description of an application recommendation method and device according to an embodiment of the present invention in conjunction with the accompanying drawings. It should be clear that the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Those skilled in the art should know that the following specific embodiments or specific implementations are a series of optimized settings listed by the present invention to further explain the specific content of the invention, and these settings can be combined or used in association with each other, unless the present invention clearly states that some or a specific embodiment or implementation cannot be associated or used together with other embodiments or implementations. At the same time, the following specific embodiments or implementations are only used as the most optimized settings, and are not to be understood as limiting the scope of protection of the present invention.

[0035] Example 1

[0036] Circuit drawing, use professional circuit design software to design the circuit pattern according to the application requirements. The pattern should include fine lines, connection points and necessary electronic component layout. Convert the designed circuit pattern into a digital file that can be used for laser, such as CAD drawings or vector graphics files.

[0037] Step 1. Circuit preparation

[0038] Choose a flexible substrate such as polyimide (PI), polyethylene terephthalate (PET) or Ecoflex silicone.

[0039] Configure a laser system to ensure that the wavelength, power and focusing performance of the laser beam meet the requirements of micro-nanoscale processing. Connect the laser system to a computer control system to accurately control the movement path and speed position of the laser beam. Load the designed circuit pattern into the computer control system as a guide for the focus and movement of the laser beam.

[0040] Start the laser system and perform laser scanning processing on the flexible substrate under the guidance of the scanning galvanometer according to the pre-designed circuit pattern. In the laser processing area, the laser induces the generation of microstructures on the surface of the flexible substrate, forming a laser-induced microstructure area and an area not processed by the laser, and obtaining a laser-processed substrate. By precisely controlling the power and scanning speed of the laser beam, it can be ensured that the line width, spacing and shape of the circuit pattern meet the design requirements;

[0041] Select a liquid metal suitable for ultrasound. These metals are liquid at room temperature and have good conductivity and machinability. Use ultrasonic pumping to pump liquid metal into the microstructure area to form a liquid metal microchannel. The magnification is usually 1.16-1.18. The ultrasonic wave length is the ultrasonic wave length propagating in the liquid metal. Connect stretchable conductive wires (such as conductive polymers, carbon nanotubes, etc.) at both ends of the liquid metal microchannel and extend outward as lead-out electrodes for connecting to external circuits to obtain a liquid metal substrate.

[0042] The liquid metal substrate is dried and solidified to ensure that the liquid metal is firmly attached to the substrate, thereby obtaining a circuit substrate.

[0043] Step 2. Substrate preparation

[0044] The circuit substrate obtained in step 1 is cleaned to remove grease, dust and other impurities on the surface, and surface activation treatment is performed to improve the adhesion and conductivity of the circuit substrate surface. The metal part is covered with a mask, and the surrounding flexible packaging part is plasma treated. In the reaction chamber of a plasma multifunctional experimental table with a voltage of 500V, under a nitrogen atmosphere, the working pressure is set to 30Pa, and the surface-modified substrate is obtained by treatment for 60 minutes.

[0045] A layer of wetting agent is coated on the surface modified substrate to obtain a wet modified substrate to reduce surface tension, make the cutting surface smoother, reduce burrs generated during the cutting process, improve cutting accuracy, and absorb and disperse heat, thereby reducing the degree of thermal damage in laser cutting, and reducing the wear and corrosion of the laser cutting machine during operation, making the laser cutting machine work more smoothly, thereby extending its service life.

[0046] Step 3. Line cutting

[0047] Use a laser cutting machine to cut the wet modified substrate into the required shape and size according to the design requirements to obtain the cut pieces, ensuring that the circuit pattern after cutting is complete and clear without breakage or short circuit.

[0048] Step 4. Heat compression packaging

[0049] The cut pieces are placed in a hot press packaging machine and packaged with adaptive elastic materials to ensure that they can maintain stable performance during deformation such as bending and stretching.

[0050] Set the temperature and pressure parameters for hot pressing packaging.

[0051] Ensure that the encapsulated electronic skin is flat, bubble-free, wrinkle-free, and has good flexibility and conductivity. Figure 1 .

[0052] Example 2

[0053] After the circuit is cut in Example 1, a film laminating step is performed: a protective film material is selected, such as polyurethane (PU), polyvinyl chloride (PVC) or biocompatible silicone, etc., and a laminating machine is used to evenly laminate the protective film on the cut piece to obtain the cut piece after laminating, ensuring that there are no bubbles or wrinkles between the protective film and the circuit pattern, and the laminating is firm, and the cut piece after laminating is hot-pressed and packaged. Other contents are consistent with Example 1, and the specific process contents are shown in Figure 2 .

[0054] Example 3

[0055] During the circuit preparation in step 1, in order to more accurately control the flow of liquid metal in the microfluidic channel and thus optimize the performance of the microfluidic system, the injection area of ​​the liquid metal, the height of the liquid metal in the channel, the total height of the microfluidic channel, and the radius of the microfluidic channel are collected through experimental measurement, sensor monitoring, or numerical simulation to calculate the proportional coefficient of the liquid metal in the microfluidic channel. The formula is as follows:

[0056]

[0057] Wherein, V represents the proportional coefficient; Q represents the volume of liquid metal to be injected; r represents the radius of the microfluidic channel; h represents the current height of the liquid metal in the channel; H represents the total height of the microfluidic channel; α represents the adjustment factor related to the fluidity of the liquid metal and the friction coefficient of the channel wall. Assuming that the channel is cylindrical, α is 2. When the value of V suddenly changes greatly at a certain height, it means that the filling state of the liquid metal at this height has changed significantly. By trying to adjust the injection speed or injection pressure to make the liquid metal more evenly distributed in the channel, the value of Q is changed, and the change in the value of V is observed; if the liquid metal is not well filled when it is close to the top of the channel, you can try to change the structure of the channel (for example, increase the height H of the channel) or adjust the properties of the liquid metal (for example, change its fluidity) to improve the filling state; this formula specifically quantifies the filling state of the liquid metal in the microfluidic channel, which helps to better understand the filling state of the liquid metal in the microfluidic channel; this formula can be used to optimize the injection process of the liquid metal to obtain a better filling effect. The other contents are consistent with Example 1, and the specific process contents are shown in Figure 3 .

[0058] Example 4

[0059] In step 1, in order to obtain the conductivity during printing in time to facilitate the adjustment of the impact on conductivity in subsequent steps, the following algorithm is used to calculate the channel resistance of the sensor. The formula is as follows:

[0060]

[0061] Where: R represents the channel resistance of the sensor; ρ LM represents the resistivity of liquid metal; L represents the length of liquid metal in the channel; A represents the contact area between liquid metal and the channel wall; ΔL represents the deformation length of liquid metal in the channel caused by external pressure; Indicates the relative length of liquid metal deformation. Other contents are consistent with Example 1.

[0062] This formula fully considers the deformation characteristics of liquid metal under external pressure, ensuring the accurate resistance measurement of the sensor under different stress states.

[0063] In the embodiment, the main component of the liquid metal is gallium 80 wt.%.

[0064] In the embodiment, a is 0.22.

[0065] In the embodiment, the adaptive elastic material is made of silicone, polyurethane thermoplastic elastomer (TPE-U) and thermoplastic polyurethane (TPU), specifically 45wt.% Dow HS-3663 medical grade silicone, 30wt.% KRAIBURG TPE-U 55D and 25wt.% BASF TPU 9370A.

[0066] The temperature of the sample was controlled by a cold water bath at 15°C while power ultrasound was applied to the device.

[0067] In the embodiment, the laser performs laser scanning under the guidance of a scanning galvanometer, with a central wavelength of 700 nm, a pulse width of 90 fs, a repetition frequency of 1.5 KHz, a scanning speed of 20 mm / s, a laser power of 250 mW, and a laser scanning interval of 50 to 350 μm.

[0068] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. If these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A preparation process of a flexible electronic sensor based on liquid metal material, comprising: Step 1. Circuit preparation: laser processing is performed on the flexible substrate to form a laser-induced microstructure area and an area not processed by the laser, liquid metal is pumped into the microstructure area to form a liquid metal microchannel, a stretchable conductive wire is connected to both ends of the liquid metal microchannel, and the circuit substrate is obtained by drying and curing; Step 2. Substrate treatment: cleaning and surface activation treatment of the circuit substrate, coating with a wetting agent to obtain a wet modified substrate.

2. The process for preparing a flexible electronic sensor based on liquid metal material according to claim 1, characterized in that: Also includes: Step 3. Circuit cutting: using a laser cutting machine to cut the wet modified substrate to obtain a cut piece; Step 4. Hot-press packaging: hot-press packaging the cut parts with the adaptive elastic material.

3. The preparation process of the flexible electronic sensor based on liquid metal material according to claim 2 is characterized in that: The method also includes laminating the circuit after cutting, laminating the protective film material on the cut piece to obtain the cut piece after laminating, and performing hot pressing packaging.

4. The process for preparing a flexible electronic sensor based on liquid metal material according to claim 1, characterized in that: The main component of the liquid metal is 80wt.% of gallium, the flexible substrate is polyimide, polyethylene terephthalate or Ecoflex silica gel, and the surface activation treatment includes covering the metal part with a mask and performing plasma treatment on the surrounding flexible packaging part.

5. The process for preparing a flexible electronic sensor based on liquid metal material according to claim 3, characterized in that: The protective film material is polyurethane, polyvinyl chloride or biocompatible silica gel.

6. The process for preparing a flexible electronic sensor based on liquid metal material according to claim 3, characterized in that: The material of the stretchable conductive wire is conductive polymer or carbon nanotube.

7. A preparation system for a flexible electronic sensor based on liquid metal material, characterized in that It comprises a circuit preparation device and a substrate processing device, wherein the circuit preparation device is used to form a laser-induced microstructure area and an area not processed by laser on a flexible substrate, liquid metal is pumped into the microstructure area to form a liquid metal microchannel, a stretchable conductive wire is connected to both ends of the liquid metal microchannel, and the circuit substrate is obtained by drying and curing; the substrate processing device comprises a substrate cleaning device, a plasma processing device and a wetting agent coating device, the substrate cleaning device is used to remove grease and dust; the plasma processing device is used to perform plasma treatment on the flexible packaging part without a mask; The wetting agent coating device is used for coating a layer of wetting agent on the surface-modified substrate to obtain a wet modified substrate.

8. The system for preparing a flexible electronic sensor based on liquid metal material according to claim 7, characterized in that: The invention also comprises a cutting device, which is used for cutting the wet modified substrate to obtain cut pieces.

9. The system for preparing a flexible electronic sensor based on liquid metal material according to claim 7, characterized in that: It also includes a packaging device, which is used to perform hot-pressing packaging on the cut pieces using the adaptive elastic material.

10. The system for preparing a flexible electronic sensor based on liquid metal material according to claim 7, characterized in that: It also includes a film sticking device, which is used to stick the protective film material on the cut piece to obtain the cut piece after film sticking, and perform hot pressing packaging.

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