Digital micro-fluidic chip temperature control system based on photothermal effect
By integrating a photothermal nanomaterial layer and a CMOS photoelectric sensor onto a digital microfluidic chip, and combining this with a PID algorithm, high-precision, customized temperature control is achieved, solving the problems of low accuracy and complex integration in traditional temperature control and reducing maintenance costs.
Patent Information
- Application Number
- CN202511610821.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-05
- Publication Date
- 2026-01-27
AI Technical Summary
Traditional digital microfluidic chips suffer from low temperature control accuracy, uncustomizable heating areas, complex integration solutions, and high maintenance costs.
The digital microfluidic chip temperature control system, which utilizes photothermal effects, integrates a photothermal nanomaterial layer and an array of CMOS photoelectric sensors, combined with a PID algorithm and a dynamic calibration module, to achieve direct conversion of light energy into heat energy and real-time temperature control.
It achieves high-precision, customized temperature control, simplifies the system integration process, reduces maintenance costs, and improves the applicability and accuracy of temperature control.
Smart Images
Figure CN121402167A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of digital microfluidics technology, and more specifically, provides a temperature control system for a digital microfluidic chip based on photothermal effects. Background Technology
[0002] The integration of functional modules into digital microfluidic systems is fundamental to achieving complex droplet manipulation and functionality, with the temperature control system being a crucial integrated module. Many biochemical reactions require specific temperatures to occur. Traditional digital microfluidic heating systems primarily rely on electrothermal methods, achieved through heating elements or the fabrication of micro-heating circuits on microfluidic chips. These systems are complex to integrate or require intricate micro / nano fabrication processes. Furthermore, the heating area of an integrated heating system is typically fixed, failing to meet the customized heating and temperature control requirements of different chips for various functional objectives.
[0003] Photothermal conversion materials are a class of materials capable of converting light energy into heat energy, typically at the nanoscale. In recent years, the photothermal conversion effect based on nanomaterials has been extensively studied. Due to their simple processing flow and non-contact heating, they have been widely applied in fields such as micro / nano actuators, soft robots, and microheaters. This invention leverages this advantage of photothermal nanomaterials, integrating them into a digital microfluidic system for heating and temperature control, aiming to solve problems such as the complexity, low temperature control accuracy, fixed heating area, and high maintenance costs of traditional integration schemes. Summary of the Invention
[0004] In response to the aforementioned technical problems, this paper presents a temperature control system for digital microfluidic chips based on photothermal effects to overcome the problems of low temperature control accuracy, uncustomizable heating areas, and lack of real-time feedback in the current use of digital microfluidic chips.
[0005] The technical means employed in this invention are as follows: A temperature control system based on a digital microfluidic chip for photothermal effect includes, from bottom to top, a system control module, a temperature sensing module, a digital microfluidic chip, and an infrared light source module. The system control module is used to manipulate the movement of droplets on the digital microfluidic chip and to perform constant-value control on the temperature of the digital microfluidic chip and the sample on it. The temperature sensing module consists of an array of CMOS photoelectric sensors, distributed in a matrix with a layout density of ≥10×10 / cm². 2 It is used to receive the intensity of transmitted light from the infrared light source module after it has been absorbed by the digital microfluidic chip module, and to convert it into the temperature on the digital microfluidic chip through the processor of the system control module; The digital microfluidic chip includes, from bottom to top, an electrode array substrate, a dielectric layer, a first hydrophobic layer, a filling dielectric layer, a second hydrophobic layer, an upper electrode plate, and a photothermal material layer. The electrode array substrate is made of ITO glass, and a driving electrode array is obtained by laser etching on it. The upper electrode plate is also made of ITO glass. The infrared light source module consists of an infrared LED array with a wavelength of 800-1000nm, and the array area covers the entire area of the digital microfluidic chip.
[0006] Furthermore, the dielectric layer is made of SU-8 3000 series photoresist, processed by spin coating exposure, with a spin coating thickness of 5~8 μm. The first hydrophobic layer and the second hydrophobic layer are obtained by spin coating hydrophobic materials onto the dielectric layer and the upper electrode plate and then heating and curing them. The thickness of the first hydrophobic layer and the second hydrophobic layer is 200~400 nm. The filling medium is silicone oil or fluorinated oil to prevent droplet evaporation during heating.
[0007] Furthermore, the photothermal material layer has a customizable pattern, and different customized structures can be achieved by designing the mask shape. Subsequently, the photothermal material is deposited on one side of the PDMS film and cured by mask-assisted spin coating or ultrasonic spraying. The photothermal material layer is encapsulated by bonding the PDMS to the upper electrode plate of the digital microfluidic chip through plasma cleaning.
[0008] Furthermore, the photothermal material is a material that can convert light energy into heat energy, selected from one or more of gold nanoparticles, graphene, and carbon nanotubes. The deposition spin-coating parameters of the photothermal material are: rotation speed 2000-6000 rpm, time 30-60 seconds, solution concentration 5-20 wt%, and thickness 50-500 nm. Furthermore, the photothermal material layer can be processed into multiple layers as needed to achieve differentiated temperature control in different regions. After each layer is processed, the photothermal material is deposited again under a microscope after realigning the mask.
[0009] Furthermore, the system control module integrates a PID algorithm and a dynamic calibration module, pre-stores the light intensity-temperature calibration curve of the photothermal material, realizes closed-loop temperature control, and achieves a control accuracy of ±0.3 ℃; the dynamic calibration module pre-stores the light intensity-temperature curve of different photothermal materials, and automatically loads the corresponding parameters when using thin films of different materials or thicknesses, with a calibration cycle of ≤1 second.
[0010] Furthermore, the processor of the system control module can receive the transmitted light signal from the temperature sensing module, calculate the light absorption of the photothermal material by the difference between the transmittance of the photothermal material region and the transmittance of the transparent region, obtain the heat absorption by integrating the irradiation time, and finally obtain the temperature data by converting the specific heat capacity of the digital microfluidic chip.
[0011] Furthermore, the system control module adopts I 2 The system communicates with the computer via C or SPI bus protocol. Before temperature control, the computer issues commands to set the temperature of different areas. During the control process, the test data is transmitted to the computer interface in real time and a temperature heat map is plotted. At the same time, the PID tuning parameters of the control system are set through the UI interface.
[0012] This invention also discloses a temperature control method for a digital microfluidic chip based on photothermal effect, implemented using any of the above-mentioned devices, comprising the following steps: S1. Light Absorbency Correction: Before heating, the system control module performs baseline calibration, turns off the infrared light source module, records the background light intensity, and deducts background noise in real time during the heating process; S2. Temperature setting: The temperature of different temperature zones is set through the computer UI interface, and the set temperature is transmitted to the system control module; S3. Temperature Control and Parameter Tuning: The array-type CMOS photoelectric sensor continuously detects transmitted light data and transmits it to the system control module. When the detected temperature is lower than the set temperature, the system control module controls the infrared light source module to start. When the temperature reaches the set temperature, the system control module controls the infrared light source module to turn off. At the same time, PID parameters can be set by computer to optimize the control effect.
[0013] Compared with the prior art, the present invention has the following advantages: 1) This invention addresses the problems of complex integration and high maintenance costs in existing digital microfluidic heating systems by employing the photothermal effect of a photothermal material layer to achieve direct conversion of light energy into heat energy, replacing the traditional complex electrothermal heating structure. The photothermal material layer is prepared using simple processes such as mask-assisted spin coating, and its packaging with the chip is simple, eliminating the need for complex micro-nano fabrication processes and significantly simplifying the system integration process. Furthermore, the customizable photothermal material layer facilitates replacement and maintenance, effectively reducing maintenance costs during subsequent use.
[0014] 2) This invention utilizes an integrated array-type CMOS photoelectric sensor to indirectly measure temperature signals by collecting transmitted light signals, resulting in higher detection accuracy and resolution. Furthermore, multi-point temperature detection of the heating area of the photothermal material layer enables real-time acquisition of temperature distribution information within the heating region.
[0015] 3) To address the issue of fixed heating areas in existing heating systems, the photothermal material layer in this invention employs a customizable design. By designing masks of different shapes, heating patterns that meet specific requirements can be fabricated. Simultaneously, by selecting photothermal materials with different light absorption properties or processing multilayer photothermal material layers, differentiated temperature control in different regions can be achieved, meeting the customized needs of various biochemical reactions for different heating areas and temperature ranges, thus significantly improving the system's applicability.
[0016] 4) To address the low temperature control accuracy of traditional technologies, this invention achieves high-precision temperature control through multiple design features. The system control module integrates a PID algorithm and a dynamic calibration module, pre-stores the light intensity-temperature calibration curve of the photothermal material, and can dynamically adjust the infrared light source output based on the difference between the real-time temperature and the set temperature to achieve closed-loop temperature control with high precision. The dynamic calibration module can automatically load parameters corresponding to different photothermal materials, with a short calibration cycle, further ensuring the accuracy of temperature control. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0018] Figure 1 This is a schematic diagram of the structure of the digital microfluidic chip of the present invention.
[0019] Figure 2 This is a schematic diagram of the overall structure of a digital microfluidic chip temperature control system based on photothermal effect according to the present invention.
[0020] Figure 3 This is a physical image of the customized photothermal material layer on the digital microfluidic chip of this invention.
[0021] Figure 4 Temperature cloud map of the customized photothermal material layer after illumination for the digital microfluidic chip of this invention.
[0022] Figure 5 A flowchart illustrating the operation of the digital microfluidic chip temperature control system based on photothermal effect provided by this invention.
[0023] Figure 6 A framework diagram of a digital microfluidic chip temperature control system based on photothermal effect provided by the present invention.
[0024] In the figure: 1. Lower electrode plate; 2. Electrode array substrate; 3. Dielectric layer; 4. Conductive tape; 5. First hydrophobic layer; 6. Second hydrophobic layer; 7. Upper electrode plate; 8. Photothermal material layer; 9. System control module; 10. CMOS photoelectric sensor; 11. Digital microfluidic chip slot; 12. Infrared light source module; 13. Top cover plate; 14. Digital microfluidic chip. Detailed Implementation
[0025] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.
[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0027] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.
[0028] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.
[0029] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.
[0030] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figures. For example, if the device in the figures is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.
[0031] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.
[0032] like Figure 1-2 As shown, this embodiment of the invention discloses a temperature control system for a digital microfluidic chip based on photothermal effect. The digital microfluidic chip includes a lower electrode plate 1 and an upper electrode plate, which are connected by a conductive tape 4. The lower electrode plate is composed of a multilayer structure, which includes, from bottom to top, an ITO glass substrate, an electrode array substrate 2, a dielectric layer 3, and a first hydrophobic layer 5. The upper electrode plate includes, from bottom to top, a second hydrophobic layer 6, an ITO glass substrate, and a photothermal material layer 8. Furthermore, the electrode array substrate 2 is fabricated on the ITO glass substrate using surface etching according to functional requirements. The dielectric layer 3 is fabricated on the electrode array substrate 2 by spin coating exposure method. The first hydrophobic layer 5 is obtained by spin coating on the dielectric layer 3 and then heating and curing. The second hydrophobic layer 6 of the upper electrode plate is obtained by spin coating and heating and curing in the same way. The medium between the upper electrode plate and the lower electrode plate is silicone oil or fluorinated oil to prevent droplet evaporation during the heating process. Furthermore, the photothermal material layer 8 is a material that can convert light energy into heat energy. Different customized structures are achieved by designing mask shapes. Subsequently, the photothermal material is deposited on one side of the PDMS film using a mask-assisted spin coating method or an ultrasonic spraying method and then cured. The photothermal material is bonded to the upper electrode plate of the digital microfluidic chip by plasma cleaning. The photothermal material layer can be processed into multiple layers according to different needs to achieve different temperature ranges in different areas. Furthermore, the array area of the infrared light source module 12 completely covers the area of the digital microfluidic chip 14, providing uniform and stable energy conversion for photothermal conversion; Furthermore, the temperature sensing module is composed of an array-type CMOS photoelectric sensor 10, which is positioned below the digital microfluidic chip 14 to receive the temperature change range of the digital microfluidic chip 14 in real time. Furthermore, such as Figure 5-6 As shown, the system control module 9 receives the transmitted light intensity signal from the array CMOS photoelectric sensor 10, and converts the light intensity data into temperature data through the light absorption-temperature calibration curves of different photothermal materials. This module integrates a PID control algorithm and a dynamic calibration module, and can control the output power of the infrared light source module 12 through closed-loop feedback based on the difference between the real-time temperature and the user-set temperature, thereby achieving high-precision temperature control of a specific area on the chip. At the same time, this module can be connected to an external computer via an SPI line to receive temperature setting commands from the computer UI interface, upload temperature data, and draw a temperature distribution heat map on the computer interface.
[0033] The following specific application examples will further illustrate the solution of the present invention.
[0034] Example 1 This embodiment provides the fabrication of a digital microfluidic chip based on photothermal materials, mainly including the following steps: S1. Electrode array substrate processing: Transparent ITO glass is selected as the base material of the electrode array substrate. The driving electrode array pattern is designed according to the requirements using CAD and other software. Then, the designed driving electrode array is processed on the ITO glass through laser etching process to form electrode array substrate 2.
[0035] S2. Dielectric layer processing: On the etched electrode array substrate 2, a layer of SU-8 3000 series photoresist is coated by spin coating, followed by exposure processing, and finally a dielectric layer 3 with a thickness of 5~8μm is formed.
[0036] S3. Hydrophobic layer processing: On the surface of dielectric layer 3, Teflon hydrophobic solution is added dropwise using a pipette and spin-coated in two steps: First, the spin-coating is performed at 100 r / s to 500 rpm for 20 s, and then at that speed for 60 s. Second, the spin-coating is performed at 300 r / s to 1500 rpm for 60 s to prepare the first hydrophobic layer 5.
[0037] S4. Photothermal material layer processing, such as Figure 3 The image shows a physical diagram of the customized photothermal material layer on the digital microfluidic chip 14. Masks for different heating regions are designed according to requirements. A photothermal material layer 8 with the designed pattern is deposited on one side of the PDMS film using a mask-assisted spin coating method. In this embodiment, gold nanoparticles are used, with a solution concentration of 10 wt%. The spin coating speed is controlled at 4000 rpm, the spin coating time is 45 seconds, and the deposition thickness is 200 nm. After curing, a customized photothermal material layer is formed.
[0038] S5. Select another clean ITO glass plate as the upper electrode plate. Clean the PDMS film and the ITO glass surface by plasma cleaning. Then bond the two together and use the same process as the lower electrode plate in S3 to prepare a second hydrophobic layer 6 on the inside of the ITO glass.
[0039] S6. Using double-sided conductive tape 4 as a connector, align and attach the upper and lower electrode plates to form a chip cavity structure. Inject silicone oil into the chip cavity as a filling medium to complete the fabrication of the digital microfluidic chip 14.
[0040] Example 2 This embodiment uses the digital microfluidic chip prepared in Example 1 to perform temperature control operations. The specific process is as follows: S1, such as Figure 2 As shown, the assembled digital microfluidic chip 14 is placed in the digital microfluidic chip slot 11, and its position is adjusted so that it is located between the infrared light source module 12 and the array CMOS photoelectric sensor 10, ensuring that the infrared light source can completely cover the chip area and that the sensor can effectively receive the transmitted light signal. A top cover plate 13 is installed on it. The temperature is set in a specific heating area of the chip through the computer UI interface, and the command is transmitted to the system control module 9 through the SPI line.
[0041] S2, the heating process of a specific area of the digital microfluidic chip 14, as shown in... Figure 5 and Figure 6 As shown, before heating, the system control module 9 performs baseline calibration, turns off the infrared light source module 12, and records the background light intensity data under the current environment. This data will be used to deduct background noise in real time during the heating process to avoid interference from ambient light on temperature detection. Upon system startup, the array-type CMOS photoelectric sensor 10 continuously monitors the transmitted light intensity data of each region of the chip and transmits the data to the system control module 9. Using a pre-stored light intensity-temperature calibration curve of the photothermal material, the transmitted light data is converted into a real-time temperature value. A PID algorithm is then used to compare the real-time temperature with the set temperature, performing light absorbance baseline calibration to turn the infrared light source module 12 on and off, achieving precise temperature control. Specifically, a customized photothermal material layer on the digital microfluidic chip 14 converts light energy into heat energy through a photothermal effect. The array-type CMOS photoelectric sensor 10 monitors the transmitted light intensity of the corresponding region in real time and transmits the data to the system control module 9. The system control module 9 converts the light intensity data into a real-time temperature using the pre-stored light intensity-temperature calibration curve of the photothermal material. A PID algorithm is then used to compare the temperature with the set temperature, dynamically adjusting the power of the infrared light source module 12 based on the temperature difference. When any temperature is lower than the set temperature, the system control module 9 controls the infrared light source module 12 to start; when the temperature reaches the set temperature, the infrared light source module 12 is turned off. Simultaneously, the computer UI displays a real-time temperature thermal map of the digital microfluidic chip 14 in pseudo-color encoded form, such as... Figure 4 As shown, this provides users with an intuitive view of temperature changes.
[0042] During temperature control, the system control module 9 transmits real-time temperature data from each region to the computer. The computer interface displays a temperature heatmap in pseudo-color encoding, visually showing the temperature distribution. Temperature fluctuations are observed through the UI, and PID tuning parameters are fine-tuned to stabilize the temperature in each region within ±0.3℃ of the set value, ensuring that the temperature requirements for biochemical reactions are met.
[0043] In summary, the digital microfluidic chip temperature control system based on photothermal effect provided by this method achieves complete customization of the heating area by using a customizable and replaceable photothermal material layer, and realizes rapid temperature control response through photothermal conversion. Combined with real-time, multi-point temperature feedback provided by an array-type CMOS photoelectric array sensor, it ensures the stability and accuracy of temperature control, and solves the problems of complex traditional integrated solutions, low temperature control accuracy, fixed heating area, and high maintenance costs.
[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A temperature control system for a digital microfluidic chip based on photothermal effect, characterized in that, From bottom to top, it includes: system control module (9), temperature sensing module, digital microfluidic chip (14) and infrared light source module (12). The system control module (9) is used to control the movement of droplets on the digital microfluidic chip (14) and to control the temperature of the digital microfluidic chip (14) and the sample on it. The temperature sensing module is composed of an array of CMOS photoelectric sensors (10), distributed in a matrix form with a layout density of ≥10×10 / cm². It is used to receive the intensity of transmitted light from the infrared light source module (12) after absorption by the digital microfluidic chip (14) module, and convert it into the temperature on the digital microfluidic chip (14) by the processor of the system control module (9). The digital microfluidic chip (14) includes, from bottom to top, an electrode array substrate (2), a dielectric layer (3), a first hydrophobic layer (5), a filling dielectric layer, a second hydrophobic layer (6), an upper electrode plate (7), and a photothermal material layer (8). The electrode array substrate (2) is made of ITO glass, and a driving electrode array is obtained by laser etching on it. The upper electrode plate (7) is also made of ITO glass. The infrared light source module (12) is composed of an infrared LED array with a wavelength of 800-1000 nm, and the array area covers the entire area of the digital microfluidic chip (14).
2. The digital microfluidic chip temperature control system according to claim 1, characterized in that, The dielectric layer (3) is made of SU-8 3000 series photoresist and is processed by spin coating exposure. The spin coating thickness is 5~8μm. The first hydrophobic layer (5) and the second hydrophobic layer (6) are obtained by spin coating hydrophobic materials on the dielectric layer (3) and the upper electrode plate (7) and heating to cure. The thickness of the first hydrophobic layer and the second hydrophobic layer is 200~400nm. The filling medium is silicone oil or fluorinated oil to prevent droplet evaporation during heating.
3. The digital microfluidic chip temperature control system according to claim 1, characterized in that, The photothermal material layer (8) has a customizable pattern. Different customized structures can be achieved by designing the mask shape. Then, the photothermal material is deposited on one side of the PDMS film and cured by mask-assisted spin coating or ultrasonic spraying. The photothermal material layer (8) is encapsulated by bonding the PDMS to the upper electrode plate (7) of the digital microfluidic chip through plasma cleaning.
4. The digital microfluidic chip temperature control system according to claim 3, characterized in that, The photothermal material is a material that can convert light energy into heat energy, and is selected from one or more of gold nanoparticles, graphene, and carbon nanotubes; the deposition spin-coating parameters of the photothermal material are: rotation speed 2000-6000 rpm, time 30-60 seconds, solution concentration 5-20 wt%, and thickness 50-500 nm.
5. The digital microfluidic chip temperature control system according to claim 4, characterized in that, The photothermal material layer (8) can be processed in multiple layers as needed to achieve differentiated temperature control in different areas. After each layer is processed, the photothermal material is deposited again under a microscope after realigning the mask.
6. The digital microfluidic chip temperature control system according to claim 1, characterized in that, The system control module (9) integrates a PID algorithm and a dynamic calibration module, pre-stores the light intensity-temperature calibration curve of the photothermal material, realizes closed-loop temperature control, and has a control accuracy of ±0.3 ℃. The dynamic calibration module pre-stores the light intensity-temperature curve of different photothermal materials, and automatically loads the corresponding parameters when using films of different materials or thicknesses, with a calibration cycle of ≤1 second.
7. The digital microfluidic chip temperature control system according to claim 6, characterized in that, The processor of the system control module can receive the transmitted light signal from the temperature sensing module, calculate the light absorption of the photothermal material by the difference between the transmittance of the photothermal material region and the transmittance of the transparent region, obtain the heat absorption by integrating the irradiation time, and finally obtain the temperature data by converting the specific heat capacity of the digital microfluidic chip (14).
8. The digital microfluidic chip temperature control system according to claim 6, further characterized in that, The system control module (9) can adopt I 2 The system communicates with the computer via C or SPI bus protocol. Before temperature control, the computer issues commands to set the temperature of different areas. During the control process, the test data is transmitted to the computer interface in real time and a temperature heat map is plotted. At the same time, the PID tuning parameters of the control system are set through the UI interface.
9. A temperature control method for a digital microfluidic chip based on photothermal effect, implemented using the device described in any one of claims 1-8, characterized in that, Includes the following steps: S1, light absorption correction: Before heating, the system control module (9) performs baseline calibration, turns off the infrared light source module (12), records the background light intensity, and deducts background noise in real time during the heating process; S2. Set temperature: Set the temperature of different temperature zones through the computer UI interface and transmit the set temperature to the system control module (9). S3. Temperature control and parameter tuning: The array-type CMOS photoelectric sensor continuously detects transmitted light data and transmits it to the system control module (9). When the detected temperature is lower than the set temperature, the system control module (9) controls the infrared light source module (12) to start. When the temperature reaches the set temperature, the infrared light source module (12) is turned off. At the same time, PID parameters can be set by computer to optimize the control effect.