Microfluidic devices and methods of using the same

Abstract

This invention discloses a microfluidic device and its usage method, belonging to the field of microfluidic technology. The microfluidic device includes a stacked microfluidic chip and a dimming device. The microfluidic chip includes a first substrate and a second substrate arranged opposite each other, with a cavity between the first and second substrates. The microfluidic chip includes a first electrode layer located on the side of the cavity away from the dimming device. The dimming device includes a third substrate and a fourth substrate arranged opposite each other, with a dimming medium layer between the third and fourth substrates. The dimming device also includes a second electrode layer located on the side of the dimming medium layer away from the microfluidic chip. The usage method is used for detecting the position of a droplet using the aforementioned microfluidic device. This invention can quickly and accurately monitor the position of droplet movement in real time, facilitating further manipulation or processing of the droplet and promoting the orderly conduct of subsequent experiments.

Description

Technical Field

[0001] This invention relates to the field of microfluidics, and more specifically, to a microfluidic device and its method of use. Background Technology

[0002] Microfluidics is a technology characterized by the manipulation of fluids at the micrometer scale. This technology has intersected with disciplines such as chemistry, biology, engineering, and physics, demonstrating broad application prospects. Droplet microfluidics, due to its advantages such as ease of fluid manipulation, high monodispersity, miniaturization, low cost, high sensitivity, and high throughput, has attracted widespread attention. The applications of microfluidic droplet technology mainly lie in the manipulation of droplets, such as achieving droplet splitting, fusion, mixing, and sorting. Therefore, microfluidics technology has extremely broad prospects in many fields, including biomedical research, drug synthesis and screening, environmental monitoring and protection, health quarantine, forensic identification, and the detection of biological reagents.

[0003] Digital microfluidics uses electrical signals to manipulate droplet movement on a substrate. By applying electricity to specific areas, the droplet's trajectory is altered, enabling operations such as droplet fusion and separation, and facilitating various biochemical reactions. Droplet movement is based on the electrowetting effect. When a droplet covers two adjacent electrodes, the contact angle on one of the activated electrodes decreases, causing the droplet to lose balance. To reduce its surface energy, the droplet moves from the unactivated electrode to the activated electrode. Current technologies require real-time monitoring of the droplet's position for further droplet manipulation or processing. Knowing the droplet's location is crucial for subsequent experiments; therefore, rapid and accurate detection of the droplet's real-time position is essential.

[0004] Therefore, providing a microfluidic device and its usage method that can quickly and accurately monitor the position of droplet movement in real time, so as to facilitate further manipulation or processing of the droplet and promote the orderly conduct of subsequent experiments, is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a microfluidic device and its method of use to solve the problem that the prior art cannot quickly and effectively monitor the position of droplets in real time.

[0006] This invention discloses a microfluidic device, comprising: a microfluidic chip and a dimming device stacked together; the microfluidic chip includes a first substrate and a second substrate disposed opposite to each other, with a cavity between the first substrate and the second substrate; the microfluidic chip includes a first electrode layer located on the side of the cavity away from the dimming device; the dimming device includes a third substrate and a fourth substrate disposed opposite to each other, with a dimming medium layer between the third substrate and the fourth substrate; the dimming device includes a second electrode layer located on the side of the dimming medium layer away from the microfluidic chip.

[0007] Based on the same inventive concept, the present invention also discloses a method of using a microfluidic device, which is at least used for detecting the position of a droplet in the microfluidic device. The method includes: placing a droplet in the cavity of the microfluidic chip, providing a first voltage signal to a first electrode layer, and providing a second voltage signal to a second electrode layer, so that an electric field is formed between the first electrode layer and the second electrode layer; under the electric field formed by the first electrode layer and the second electrode layer, the transmittance at the position of the droplet in the dimming device is different from the transmittance at other positions of the dimming device, thereby determining the position of the droplet.

[0008] Compared with the prior art, the microfluidic device and its method of use provided by the present invention achieve at least the following beneficial effects:

[0009] In the microfluidic device provided by the present invention, a microfluidic chip and a dimming device are stacked. The microfluidic chip is used as a carrier for droplet manipulation, and the droplets can perform a series of operations in the microfluidic chip, such as moving, separating, and mixing. The dimming device is used to monitor the position of the droplets in the microfluidic chip in real time. When a droplet moves within the containment cavity of a microfluidic chip, different voltage signals can be applied to the first and second electrode layers, creating a driving electric field between them. Due to water polarization at the droplet's location, the driving electric field of the dimming medium layer at the droplet's location differs from that at other locations. This results in a difference in transmittance between the dimming medium layer at the droplet's location and that at other locations. This difference in transmittance is visually reflected as a difference in color. By observing the color differences in different areas of the dimming device, the droplet's position within the microfluidic chip's containment cavity can be quickly determined. This allows for rapid and accurate real-time monitoring of the droplet's movement within the chip, facilitating further manipulation or processing and ensuring the orderly conduct of subsequent experiments.

[0010] Of course, any product implementing this invention need not necessarily achieve all of the technical effects described above at the same time.

[0011] Other features and advantages of the invention will become clear from the following detailed description of exemplary embodiments of the invention with reference to the accompanying drawings. Attached Figure Description

[0012] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the invention and, together with their description, serve to explain the principles of the invention.

[0013] Figure 1 This is a schematic diagram of the microfluidic device provided in an embodiment of the present invention;

[0014] Figure 2 yes Figure 1 A state structure diagram of the provided microfluidic device when monitoring droplet position;

[0015] Figure 3 This is another structural schematic diagram of the microfluidic device provided in the embodiments of the present invention;

[0016] Figure 4 This is another structural schematic diagram of the microfluidic device provided in the embodiments of the present invention;

[0017] Figure 5 This is another structural schematic diagram of the microfluidic device provided in the embodiments of the present invention;

[0018] Figure 6 yes Figure 1 A structural diagram of the microfluidic device in its initial state before droplet position monitoring;

[0019] Figure 7 yes Figure 6 A state structure diagram for droplet position monitoring;

[0020] Figure 8 This is another structural schematic diagram of the microfluidic device provided in the embodiments of the present invention;

[0021] Figure 9 yes Figure 1 Another structural diagram of the microfluidic device in its initial state before droplet position monitoring;

[0022] Figure 10 yes Figure 9 A state structure diagram for droplet position monitoring;

[0023] Figure 11 This is another structural schematic diagram of the microfluidic device provided in the embodiments of the present invention;

[0024] Figure 12 yes Figure 1 A structural diagram of the microfluidic device in its initial state before droplet position monitoring;

[0025] Figure 13 yes Figure 12 A state structure diagram for droplet position monitoring;

[0026] Figure 14 yes Figure 1 A structural diagram of the microfluidic device in its initial state before droplet position monitoring;

[0027] Figure 15 yes Figure 14 A state structure diagram for droplet position monitoring;

[0028] Figure 16 This is another structural schematic diagram of the microfluidic device provided in the embodiments of the present invention;

[0029] Figure 17 This is another structural schematic diagram of the microfluidic device provided in the embodiments of the present invention;

[0030] Figure 18 This is another structural schematic diagram of the microfluidic device provided in the embodiments of the present invention;

[0031] Figure 19 This is another structural schematic diagram of the microfluidic device provided in the embodiments of the present invention;

[0032] Figure 20 This is another structural schematic diagram of the microfluidic device provided in the embodiments of the present invention;

[0033] Figure 21 yes Figure 20 A state structure diagram of the provided microfluidic device when monitoring droplet position;

[0034] Figure 22 This is another structural schematic diagram of the microfluidic device provided in the embodiments of the present invention;

[0035] Figure 23 This is another structural schematic diagram of the microfluidic device provided in the embodiments of the present invention;

[0036] Figure 24 yes Figure 23 A state structure diagram of the provided microfluidic device when monitoring droplet position;

[0037] Figure 25 This is another structural schematic diagram of the microfluidic device provided in the embodiments of the present invention;

[0038] Figure 26 This is another structural schematic diagram of the microfluidic device provided in the embodiments of the present invention;

[0039] Figure 27This is another structural schematic diagram of the microfluidic device provided in the embodiments of the present invention;

[0040] Figure 28 yes Figure 25 A state structure diagram of the provided microfluidic device when monitoring droplet position;

[0041] Figure 29 This is another structural schematic diagram of the microfluidic device provided in the embodiments of the present invention;

[0042] Figure 30 This is another structural schematic diagram of the microfluidic device provided in the embodiments of the present invention;

[0043] Figure 31 This is another structural schematic diagram of the microfluidic device provided in the embodiments of the present invention;

[0044] Figure 32 This is another structural schematic diagram of the microfluidic device provided in the embodiments of the present invention;

[0045] Figure 33 yes Figure 32 A state structure diagram of the provided microfluidic device when monitoring droplet position;

[0046] Figure 34 This is another structural schematic diagram of the microfluidic device provided in the embodiments of the present invention;

[0047] Figure 35 This is another structural schematic diagram of the microfluidic device provided in the embodiments of the present invention;

[0048] Figure 36 yes Figure 35 A state structure diagram of the provided microfluidic device when monitoring droplet position;

[0049] Figure 37 This is a flowchart illustrating the method of using the microfluidic device provided in the embodiments of the present invention;

[0050] Figure 38 This is a flowchart illustrating another method of using the microfluidic device provided in this embodiment of the invention.

[0051] Figure 39 This is a flowchart illustrating another method of using the microfluidic device provided in this embodiment of the invention. Detailed Implementation

[0052] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention.

[0053] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0054] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0055] In all the 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.

[0056] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0057] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of the microfluidic device provided in an embodiment of the present invention. The microfluidic device 000 provided in this embodiment includes: a microfluidic chip 10 and a dimming device 20 stacked together.

[0058] The microfluidic chip 10 includes a first substrate 101 and a second substrate 102 disposed opposite to each other, with a receiving cavity 103 between the first substrate 101 and the second substrate 102; the microfluidic chip 10 includes a first electrode layer 104, which is located on the side of the receiving cavity 103 away from the dimming device 20.

[0059] The dimming device 20 includes a third substrate 201 and a fourth substrate 202 disposed opposite to each other, with a dimming medium layer 203 between the third substrate 201 and the fourth substrate 202; the dimming device 20 includes a second electrode layer 204, which is located on the side of the dimming medium layer 203 away from the microfluidic chip 10.

[0060] Specifically, the microfluidic device 000 provided in this embodiment includes a microfluidic chip 10 and a dimming device 20. The microfluidic chip 10 and the dimming device 20 are stacked. The microfluidic chip 10 is used as a carrier for droplet manipulation. The droplets can perform a series of operations in the microfluidic chip 10, such as moving, separating, and mixing. The dimming device 20 is used to monitor the position of the droplets in the microfluidic chip 10 in real time.

[0061] The microfluidic chip 10 of this embodiment includes a first substrate 101 and a second substrate 102 disposed opposite to each other. Optionally, in this embodiment, the first substrate 101 is located on the side of the second substrate 102 away from the dimming device 20 as an example. In specific implementation, the naming of the first substrate 101 and the second substrate 102 is only used to distinguish the two substrates of the microfluidic chip 10. The substrate closer to the dimming device 20 can also be named the first substrate 101. This embodiment does not make a specific limitation. The first substrate 101 and the second substrate 102 of this embodiment include a receiving cavity 103. The receiving cavity 103 is used as a cavity for droplet travel. Optionally, the receiving cavity 103 may include a space with a certain height in which the droplet can travel sufficiently. It is understood that the microfluidic device 000 of this embodiment does not include the droplet M. The droplet M can be placed in the receiving cavity 103 during the operation of the microfluidic device 000. Figure 2 As shown, Figure 2 yes Figure 1 This is a structural diagram of a microfluidic device performing droplet position monitoring. The microfluidic chip 10 includes a first electrode layer 104, which is located on the side of the receiving cavity 103 away from the dimming device 20. It is understood that this embodiment does not specifically limit the shape of the first electrode layer 104; the first electrode layer 104 can be a planar structure (e.g., a monolithic structure). Figure 1 As shown in the figure, the first electrode layer 104 can also be divided into multiple block-shaped or strip-shaped structures (not shown in the figure). This embodiment does not specifically limit the shape of the first electrode layer 104; in specific implementation, it can be selected and set according to actual needs. Optionally, the first electrode layer 104 can be disposed on the first substrate 101, in which case the first substrate 101 is located on the side of the second substrate 102 away from the dimming device 20 (e.g., ...). Figure 1 (As shown in the figure); the first electrode layer 104 can also be disposed on the second substrate 102, in which case the second substrate 102 is located on the side of the first substrate 101 away from the dimming device 20 (not shown in the figure). This embodiment does not make specific limitations, as long as the first electrode layer 104 is located on the side of the receiving cavity 103 away from the dimming device 20. This embodiment Figure 1 The illustration is based on the example of the first electrode layer 104 being located on the side of the first substrate 101 away from the second substrate 102. In a specific implementation, the first electrode layer 104 may also be located on the side of the first substrate 101 facing the second substrate 102. This embodiment will not be elaborated here.

[0062] The dimming device 20 in this embodiment includes a third substrate 201 and a fourth substrate 202 disposed opposite to each other. Optionally, this embodiment uses the example of the third substrate 201 being located on the side of the fourth substrate 202 closer to the microfluidic chip 10. In specific implementation, the naming of the third substrate 201 and the fourth substrate 202 is only used to distinguish the two substrates of the dimming device 20. The substrate closer to the microfluidic chip 10 can also be named the fourth substrate 202. This embodiment does not make a specific limitation. It can be understood that the microfluidic chip 10 and the dimming device 20 are stacked in this embodiment. The stacking can be achieved by bonding and fixing the substrate of the microfluidic chip 10 and the substrate of the dimming device 20 together (e.g., ...). Figure 1 As shown in the figure, the substrates of the two can also not be in direct contact. For example, other structures (not shown in the figure) can be included between the microfluidic chip 10 and the dimming device 20 to achieve bonding and fixing of the microfluidic chip 10 and the dimming device 20. This embodiment is not limited, as long as the microfluidic chip 10 and the dimming device 20 are stacked.

[0063] In this embodiment, a dimming dielectric layer 203 is included between the third substrate 201 and the fourth substrate 202. The dimming dielectric layer 203 can achieve different transmittances under different driving electric fields. The dimming device 20 includes a second electrode layer 204, which is located on the side of the dimming dielectric layer 203 away from the microfluidic chip 10. It is understood that this embodiment does not specifically limit the shape of the second electrode layer 204, and the second electrode layer 204 can be a planar structure (e.g., Figure 1 As shown in the figure, the second electrode layer 204 can also be divided into multiple block-shaped or strip-shaped structures (not shown in the figure). This embodiment does not specifically limit the shape of the second electrode layer 204; in specific implementation, it can be selected and set according to actual needs. Optionally, the second electrode layer 204 can be disposed on the third substrate 201, in which case the third substrate 201 is located on the side of the fourth substrate 202 away from the microfluidic chip 10 (not shown in the figure); the second electrode layer 204 can also be disposed on the fourth substrate 202, in which case the fourth substrate 202 is located on the side of the third substrate 201 away from the microfluidic chip 10 (e.g., as shown in the figure). Figure 1 As shown in the figure, this embodiment is not specifically limited, only requiring that the second electrode layer 204 is located on the side of the dimming medium layer 203 away from the microfluidic chip 10. This embodiment Figure 1 The illustration is based on the example of the second electrode layer 204 being located on the side of the fourth substrate 202 away from the third substrate 201. In a specific implementation, the second electrode layer 204 may also be located on the side of the fourth substrate 202 facing the third substrate 201. This embodiment will not be elaborated here.

[0064] In this embodiment, the first electrode layer 104 located on the side of the receiving cavity 103 away from the dimming device 20 and the second electrode layer 204 located on the side of the dimming medium layer 203 away from the microfluidic chip 10 are used to generate a driving electric field. When the droplet moves in the receiving cavity 103 of the microfluidic chip 10, different voltage signals can be applied to the first electrode layer 104 and the second electrode layer 204 respectively, so that a driving electric field is formed between the first electrode layer 104 and the second electrode layer 204. Due to the polarization of water at the location of the droplet, the partial voltage at the location of the droplet in the microfluidic chip 10 is small, and the partial voltage in the area outside the droplet (most of which is air) in the microfluidic chip 10 is large. Since the voltage U = Q / C, where Q refers to the charge and C refers to the capacitance, and the capacitance C = εS / d, that is, in this embodiment, the facing area S and the distance d of the first electrode layer 104 and the second electrode layer 204 are the same, and the capacitance C is proportional to the dielectric constant ε of the medium itself. If the dielectric constant of a droplet (water) is greater than that of air, then the capacitance C at the droplet location is larger. If the charge Q between the first electrode layer 104 and the second electrode layer 204 is equal, then the voltage at the droplet location is smaller, that is, the voltage drop at the droplet location is smaller. The driving electric field between the first electrode layer 104 and the second electrode layer 204 of the microfluidic device 000 is the same. Therefore, the electric field strength is high in some areas of the dimming device 20 corresponding to the droplet location, and low in some areas of the dimming device 20 corresponding to other locations. That is, the driving electric field of the dimming medium layer 203 at the droplet location is different from that at other locations. This results in a difference in transmittance between the dimming medium layer 203 at the droplet location and the dimming medium layer 203 at other locations. The difference in transmittance is generally reflected in the visual effect as a difference in color. Based on the different colors in different areas of the dimming device 20, the position of the droplet in the receiving cavity 103 of the microfluidic chip 10 can be quickly determined. This allows for rapid and accurate real-time monitoring of the droplet's movement within the microfluidic chip 10, facilitating further manipulation or processing of the droplet and promoting the orderly conduct of subsequent experiments.

[0065] It is understood that in this embodiment Figure 1 The diagram only illustrates the structure of the microfluidic chip 10 and the dimming device 20. In actual implementation, the structure of the microfluidic chip 10 and the dimming device 20 includes, but is not limited to, this. The microfluidic chip 10 may also include structures such as driving electrodes for driving droplet movement and hydrophobic layers. Figure 1 (The text is incomplete and appears to be missing information. A more accurate translation would require the full context.) Figure 1 This example only uses the dimming medium layer 203 as a liquid crystal layer. The specific implementation includes, but is not limited to, this. It is only necessary to ensure that the dimming medium layer 203 can achieve different transmittance under different electric field intensities. This embodiment does not limit the specific materials of the dimming medium layer 203.

[0066] It should be noted that the specific placement positions of the first substrate 101, the second substrate 102, the third substrate 201, and the fourth substrate 202 in this embodiment are not limited. It is only required that the first electrode layer 104 is disposed on one of the first substrate 101 and the second substrate 102, the second electrode layer 204 is disposed on one of the third substrate 201 and the fourth substrate 202, and the first electrode layer 104 is located on the side of the receiving cavity 103 away from the dimming device 20, the second electrode layer 204 is located on the side of the dimming medium layer 203 away from the microfluidic chip 10, and the first electrode layer 104 and the second electrode layer 204 can form different electric fields at the droplet-containing and droplet-free locations, thereby achieving different transmittance of the dimming medium layer 203. The microfluidic device 000 of this embodiment may also include other structures, such as a sealing frame adhesive, a driving circuit for driving the droplet to move, and a driving circuit for driving the light transmission of the dimming medium layer 203. These will not be described in detail here. For specific details, please refer to the structure of the microfluidic chip and dimming device in the related art for understanding and configuration.

[0067] Optionally, in this embodiment, the first substrate 101, the second substrate 102, the third substrate 201, and the fourth substrate 202 are arranged sequentially in the direction Z perpendicular to the plane where the first substrate 101 is located. The first electrode layer 104 can be located on the side of the first substrate 101 away from the second substrate 102, and the second electrode layer 204 can be located on the side of the fourth substrate 202 away from the third substrate 201 (e.g., ...). Figure 1 (as shown);

[0068] Alternatively, the first electrode layer 104 may be located on the side of the first substrate 101 facing the second substrate 102, and the second electrode layer 204 may be located on the side of the fourth substrate 202 facing the third substrate 201 (e.g., Figure 3 As shown, Figure 3 (This is another structural schematic diagram of the microfluidic device provided in the embodiment of the present invention). It is beneficial to protect the first electrode layer 104 and the second electrode layer 204. At this time, the first electrode layer 104 can also be patterned and reused as a driving electrode to drive the droplet. It can also reduce the distance between the first electrode layer 104 and the second electrode layer 204 in the direction Z perpendicular to the plane where the first substrate 101 is located, which is beneficial to enhance the electric field strength between the first electrode layer 104 and the second electrode layer 204. The following embodiments will provide specific descriptions, and this embodiment will not be repeated here.

[0069] Alternatively, the first electrode layer 104 may be located on the side of the first substrate 101 facing the second substrate 102, and the second electrode layer 204 may be located on the side of the fourth substrate 202 away from the third substrate 201 (e.g., Figure 4 As shown, Figure 4 (This is another structural schematic diagram of the microfluidic device provided in the embodiment of the present invention). Since the first electrode layer 104 is located on the side of the first substrate 101 facing the second substrate 102, that is, the first electrode layer 104 is located inside the receiving cavity 103 of the microfluidic chip 10, it can protect the first electrode layer 104 while also making the first electrode layer 104 closer to the second electrode layer 204. At this time, the first electrode layer 104 can also be patterned and reused as a driving electrode for driving droplet movement, which is beneficial to reducing the overall thickness of the microfluidic device 000. The following embodiments will provide specific descriptions, and this embodiment will not be repeated here.

[0070] Alternatively, the first electrode layer 104 may be located on the side of the first substrate 101 away from the second substrate 102, and the second electrode layer 204 may be located on the side of the fourth substrate 202 facing the third substrate 201 (e.g., Figure 5 As shown, Figure 5 (This is another structural schematic diagram of the microfluidic device provided in the embodiment of the present invention). Since the second electrode layer 204 is located in the box formed by the third substrate 201 and the fourth substrate 202, it can protect the second electrode layer 204 and make the second electrode layer 204 closer to the first electrode layer 104, which is beneficial to enhance the electric field and achieve better monitoring effect.

[0071] In some alternative embodiments, please refer to the references. Figure 1 , Figure 6 and Figure 7 , Figure 6 yes Figure 1 A structural diagram of the microfluidic device in its initial state before droplet position monitoring. Figure 7 yes Figure 6 A state structure diagram during droplet position monitoring. In this embodiment, the dimming medium layer 203 includes a plurality of positive liquid crystal molecules 2031 and a plurality of positive dichroic dye molecules 2032.

[0072] A first alignment film layer 205 is disposed on the surface of the third substrate 201 facing the dimming medium layer 203, and a second alignment film layer 206 is disposed on the surface of the fourth substrate 202 facing the dimming medium layer 203.

[0073] The alignment direction of the first alignment film layer 205 is the same as that of the second alignment film layer 206, and both are horizontally aligned.

[0074] This embodiment explains that the dimming medium layer 203 in the dimming device 20 can be a liquid crystal layer, wherein the liquid crystal layer includes a mixed structure of multiple positive liquid crystal molecules 2031 and multiple positive dichroic dye molecules 2032 (distinguished by different filling patterns in the figure). A first alignment film layer 205 is disposed on the surface of the third substrate 201 facing the dimming medium layer 203, and a second alignment film layer 206 is disposed on the surface of the fourth substrate 202 facing the dimming medium layer 203. The alignment direction of the first alignment film layer 205 is the same as the alignment direction of the second alignment film layer 206, and both are horizontally aligned (e.g., ...). Figure 6 As shown, the long axis direction of the positive liquid crystal molecule 2031 can be the same as the first direction X, or it can be perpendicular to the plane of the paper in the figure. That is, when the positive liquid crystal molecule 2031 in the dimming medium layer 203 is rotated 90 degrees in the horizontal direction, its long axis direction is perpendicular to the plane of the paper in the figure, but it is still horizontally aligned. This embodiment is only an example of the possible initial state of the positive liquid crystal molecule 2031 when horizontally aligned, and does not represent the actual initial setting state. It can also be other horizontal directions, but they are all horizontally aligned. Among them, the first direction X is the direction parallel to the plane where the first substrate 101 is located. It can be understood that this embodiment Figure 6 The example is given by taking the positive liquid crystal molecule 2031 whose long axis is the same as the first direction X.

[0075] In this embodiment, the dimming dielectric layer 203 includes a plurality of positive liquid crystal molecules 2031 and a plurality of positive dichroic dye molecules 2032. The dielectric constant of the positive liquid crystal molecules 2031 along its long axis is greater than that along its short axis, so that when it is controlled by an electric field, the long axis of the positive liquid crystal molecules 2031 can be deflected along a direction parallel to the electric field direction, while when it is not controlled by an electric field, the long axis of the positive liquid crystal molecules 2031 is the same as the alignment direction of its adjacent alignment film layer, such as... Figure 6 The orientation direction (first direction X) of the alignment film is the same. Since liquid crystal molecules exhibit dielectric and refractive index anisotropy, their arrangement can be altered by an electric field. Although the positive dichroic dye molecule 2032 lacks dielectric anisotropy (is not controlled by an electric field), when dissolved in the oriented positive liquid crystal molecules 2031, the positive dichroic dye molecule 2032 will deflect along with the deflection of the positive liquid crystal molecules 2031, ultimately aligning itself in the same direction as the positive liquid crystal molecules 2031. The positive dichroic dye molecule 2032 is used to absorb linearly polarized light or linearly polarized light components whose polarization direction is parallel to the long axis of the positive dichroic dye molecule 2032.

[0076] like Figure 6As shown, when no electric field is formed between the first electrode layer 104 and the second electrode layer 204, the positive liquid crystal molecules 2031 are in a basically flat state (affected by the horizontal alignment of the alignment direction of the first alignment film layer 205 and the alignment direction of the second alignment film layer 206), and the positive dichroic dye molecules 2032 are also in a basically flat state. When the dimming device 20 is subjected to external linearly polarized light, the polarization (vibration) direction is parallel to the long axis direction of the positive dichroic dye molecules 2032, and the light is absorbed by the positive dichroic dye molecules 2032. At this time, the dimming device 20 is in a normally black state. That is, the dimming device 000 of this embodiment is in a normally black mode when the droplet position is not monitored, so that when the droplet position is monitored (i.e., after the first electrode layer 104 and the second electrode layer 204 are energized), the position of the droplet M changes from black to white, making it easier to observe visually.

[0077] like Figure 7 As shown, when monitoring the position of droplet M is required, different voltage signals can be applied to the first electrode layer 104 and the second electrode layer 204 respectively (e.g., applying a 0V voltage signal to the first electrode layer 104 and a 200V voltage signal to the second electrode layer 204). This creates a sufficiently large electric field between the first electrode layer 104 and the second electrode layer 204, with the direction of this electric field perpendicular to the plane of the first substrate 101. The positive liquid crystal molecules 2031 are deflected by this perpendicular electric field, and their long axis direction is aligned with the direction of the electric field (e.g., ...). Figure 7 When the positive liquid crystal molecule 2031 drives the positive dichroic dye molecule 2032 to deflect together, the polarization (vibration) direction of the linearly polarized light received by the dimming device 20 is not parallel to the long axis direction of the positive dichroic dye molecule 2032. Therefore, the linearly polarized light entering the dimming device 20 will not be absorbed by the positive dichroic dye molecule 2032 and will all be emitted normally.

[0078] Due to water polarization at the droplet location within the microfluidic chip 10, the partial pressure at the droplet location is low, while the partial pressure in the area outside the droplet (mostly air) is high. Since the intensity of the vertical electric field formed between the first electrode layer 104 and the second electrode layer 204 of the microfluidic device 000 is the same, the electric field intensity is high in some areas of the dimming device 20 corresponding to the droplet location, and low in some areas of the dimming device 20 corresponding to locations outside the droplet location. This means the dimming dielectric layer 203 at the droplet location... The magnitude of the driving electric field is different from that of the dimming medium layer 203 outside the droplet. This causes the angle at which the positive liquid crystal molecules 2031 and positive dichroic dye molecules 2032 of the dimming device 20 at the droplet location deflect together to be different from the angle at which the positive liquid crystal molecules 2031 and positive dichroic dye molecules 2032 of the dimming device 20 at the location outside the droplet deflect together. Since the deflection angles of the positive liquid crystal molecules 2031 and positive dichroic dye molecules 2032 are different in different regions, the visual color of the dimming device 20 is also different in different regions. Specifically, when no electric field is formed between the first electrode layer 104 and the second electrode layer 204, the dimming device 20 is in a normally black mode. After a vertical electric field is formed between the first electrode layer 104 and the second electrode layer 204, the electric field intensity is high in a certain area of ​​the dimming device 20 corresponding to the droplet location, and the positive liquid crystal molecules 2031 and positive dichroic dye molecules 2032 deflect together at a large angle, making the dimming device 20 corresponding to the droplet location appear whiter and have higher light transmittance. Conversely, the electric field intensity is low in a certain area of ​​the dimming device 20 outside the droplet location, and the positive liquid crystal molecules 2031 and positive dichroic dye molecules 2032 deflect together at a large angle, resulting in a whiter visual effect and higher light transmittance for the dimming device 20 corresponding to the droplet location. The liquid crystal molecule 2031 and the positive dichroic dye molecule 2032 deflect together at a small angle (they may not yet be fully upright). The dimming device 20 at the position outside the droplet is not as white as the droplet position (it is likely to be gray or blackish) and has low light transmittance. This allows for the rapid determination of the droplet's position within the containment cavity 103 of the microfluidic chip 10. Consequently, the movement of the droplet within the microfluidic chip 10 can be monitored in real time quickly and accurately, facilitating further manipulation or processing of the droplet and promoting the orderly conduct of subsequent experiments.

[0079] It is understood that in this embodiment Figure 6 and Figure 7 The diagram only illustrates the initial state and deflection angle of the positive liquid crystal molecules 2031 and the positive dichroic dye molecules 2032, and does not represent the actual deflection angle under the driving electric field. In specific implementations, the magnitude of the deflection angle of the positive liquid crystal molecules 2031 and the positive dichroic dye molecules 2032 is related to the electric field strength. The quantity and mixing ratio of the positive liquid crystal molecules 2031 and the positive dichroic dye molecules 2032 in the diagram of this embodiment are only examples and do not represent the actual quantity. In specific implementations, they can be set according to actual needs.

[0080] It should be noted that the first electrode layer 104 and the second electrode layer 204 in this embodiment can be a transparent conductive film of indium tin oxide (ITO) with high transmittance and high conductivity deposited on the surface of the first substrate 101 and the fourth substrate 202 (such as a transparent glass substrate), or it can be fabricated by other methods. In this embodiment, the long axis direction of the positive dichroic dye molecule 2032 changes with the long axis direction of the positive liquid crystal molecule 2031, and always remains consistent with the long axis direction of the positive liquid crystal molecule 2031. In this embodiment, the mixing ratio of positive liquid crystal molecule 2031 and positive dichroic dye molecule 2032 in the dimming medium layer 203 is not specifically limited, as long as the two are uniformly mixed and all positive dichroic dye molecules 2032 can be deflected with the positive liquid crystal molecule 2031, this embodiment does not make specific limitations. The first alignment film layer 205 and the second alignment film layer 206 in this embodiment can generally be formed by printing a polymer film (e.g., polyimide) on a glass substrate (the third substrate 201 and the fourth substrate 202 in this embodiment), but it is not limited to this and can also be formed by other methods, which will not be described in detail in this embodiment.

[0081] In some alternative embodiments, please refer to the references. Figure 7 and Figure 8 , Figure 8 This is another structural schematic diagram of the microfluidic device provided in this embodiment of the invention. In this embodiment, the dimming medium layer 203 includes a plurality of positive liquid crystal molecules 2031 and a plurality of positive dichroic dye molecules 2032; a first alignment film layer 205 is disposed on the surface of the third substrate 201 facing the dimming medium layer 203, and a second alignment film layer 206 is disposed on the surface of the fourth substrate 202 facing the dimming medium layer 203; the alignment direction of the first alignment film layer 205 is the same as the alignment direction of the second alignment film layer 206 and both are horizontally aligned, wherein the initial pretilt angle α1 of the positive liquid crystal molecules 2031 is in the range of 3°-10°.

[0082] This embodiment explains that the initial pretilt angle α1 of the positive liquid crystal molecule 2031 ranges from 3° to 10°. That is, in the initial state where the first electrode layer 104 and the second electrode layer 204 are not energized, the angle between the long axis of the positive liquid crystal molecule 2031 and the plane (e.g., the first direction X) where the first substrate 101 is located is 3° to 10°. Therefore, when monitoring the droplet position, after applying a voltage to the first electrode layer 104 and the second electrode layer 204 to form a perpendicular electric field, the positive liquid crystal molecule 2031 can more quickly deflect according to the direction of the electric field until its long axis is parallel to the direction of the electric field (e.g., the direction X). Figure 7(It deflects faster toward the standing direction), which helps to shorten the reaction time of positive liquid crystal molecules 2031 under the drive of an electric field.

[0083] In some alternative embodiments, please refer to the references. Figure 1 , Figure 9 and Figure 10 , Figure 9 yes Figure 1 Another structural diagram of the provided microfluidic device in its initial state before droplet position monitoring. Figure 10 yes Figure 9 A state structure diagram during droplet position monitoring. In this embodiment, the dimming medium layer 203 includes multiple negative liquid crystal molecules 2033 and multiple positive dichroic dye molecules 2032.

[0084] A third alignment film layer 207 is provided on the surface of the third substrate 201 facing the dimming medium layer 203, and a fourth alignment film layer 208 is provided on the surface of the fourth substrate 202 facing the dimming medium layer 203.

[0085] The alignment direction of the third alignment film layer 207 is the same as that of the fourth alignment film layer 208, and both are perpendicular alignments.

[0086] This embodiment explains that the dimming medium layer 203 in the dimming device 20 can be a liquid crystal layer, wherein the liquid crystal layer includes a mixed structure of multiple negative liquid crystal molecules 2033 and multiple positive dichroic dye molecules 2032 (distinguished by different filling patterns in the figure). A third alignment film layer 207 is disposed on the surface of the third substrate 201 facing the dimming medium layer 203, and a fourth alignment film layer 208 is disposed on the surface of the fourth substrate 202 facing the dimming medium layer 203. The alignment direction of the third alignment film layer 207 is the same as the alignment direction of the fourth alignment film layer 208, and both are perpendicular alignment (e.g., ...). Figure 9 As shown, the long axis direction of the negative liquid crystal molecule 2033 can be the same as the direction Z perpendicular to the plane where the first substrate 101 is located, so that its initial state is an upright state. It can be understood that in this embodiment... Figure 6 The example is given by taking the case where the long axis of the negative liquid crystal molecule 2033 is the same as the direction Z perpendicular to the plane of the first substrate 101.

[0087] The dimming dielectric layer 203 of this embodiment includes a plurality of negative liquid crystal molecules 2033 and a plurality of positive dichroic dye molecules 2032. The dielectric constant of the negative liquid crystal molecules 2033 in the long axis direction is smaller than that in the short axis direction, so that when they are controlled by an electric field, the long axis direction of the negative liquid crystal molecules 2033 can be deflected along the direction perpendicular to the electric field direction (from a standing state to a lying state, where the standing state in this embodiment means that the long axis direction of the liquid crystal is the same as the direction perpendicular to the plane of the first substrate 101, and the lying state in this embodiment means that the long axis direction of the liquid crystal is the same as the direction parallel to the plane of the first substrate 101). When they are not controlled by an electric field, the long axis direction of the negative liquid crystal molecules 2033 is the same as the alignment direction of their adjacent alignment film layer, such as... Figure 9 The alignment direction of the liquid crystal molecules is the same as that of the alignment film (direction Z perpendicular to the plane of the first substrate 101). Since liquid crystal molecules exhibit dielectric and refractive index anisotropy, their arrangement can be altered by an electric field. Although the positive dichroic dye molecule 2032 lacks dielectric anisotropy (is not controlled by an electric field), when dissolved in the oriented negative liquid crystal molecules 2033, the positive dichroic dye molecule 2032 will deflect along with the negative liquid crystal molecules 2033, ultimately aligning with them in the same direction. The positive dichroic dye molecule 2032 is used to absorb linearly polarized light or linearly polarized light components whose polarization direction is parallel to the long axis of the positive dichroic dye molecule 2032.

[0088] like Figure 9 As shown, when no electric field is formed between the first electrode layer 104 and the second electrode layer 204, the negative liquid crystal molecules 2033 are in a basically upright state (affected by the perpendicular alignment of the alignment direction of the third alignment film layer 207 and the alignment direction of the fourth alignment film layer 208), and the positive dichroic dye molecules 2032 are also in a basically upright state. The polarization (vibration) direction of the linearly polarized light received by the dimming device 20 is perpendicular to the long axis direction of the positive dichroic dye molecules 2032, and the light is not absorbed by the positive dichroic dye molecules 2032, and all of it is emitted normally. At this time, the dimming device 20 is in a normally white state. That is, the dimming device 000 of this embodiment is in a normally white mode when the droplet position is not monitored, so that when the droplet position is monitored (i.e., after the first electrode layer 104 and the second electrode layer 204 are energized), the position of the droplet M changes from white to black.

[0089] like Figure 10As shown, when monitoring the position of droplet M is required, different voltage signals can be applied to the first electrode layer 104 and the second electrode layer 204 respectively (e.g., applying a 0V voltage signal to the first electrode layer 104 and a 200V voltage signal to the second electrode layer 204). This creates a sufficiently large electric field between the first electrode layer 104 and the second electrode layer 204, with the direction of this electric field perpendicular to the plane of the first substrate 101. The negative liquid crystal molecules 2033 are deflected by this perpendicular electric field, and their long axis direction becomes perpendicular to the direction of the electric field (e.g., ...). Figure 10 In the deflection state, the negative liquid crystal molecules 2033 will deflect in the direction of lying flat. The negative liquid crystal molecules 2033 will drive the positive dichroic dye molecules 2032 to deflect together. At this time, the polarization (vibration) direction of the linearly polarized light received by the dimming device 20 from the outside is basically parallel or close to the long axis direction of the positive dichroic dye molecules 2032. Then, the linearly polarized light entering the dimming device 20 will be absorbed by the positive dichroic dye molecules 2032 and will not be emitted. The color of the dimming device 20 changes from white to black (or gray).

[0090] Due to water polarization at the droplet location within the microfluidic chip 10, the partial pressure at the droplet location is low, while the partial pressure in the area outside the droplet (mostly air) is high. Since the intensity of the vertical electric field formed between the first electrode layer 104 and the second electrode layer 204 of the microfluidic device 000 is the same, the electric field intensity is high in some areas of the dimming device 20 corresponding to the droplet location, and low in some areas of the dimming device 20 corresponding to locations outside the droplet location. This means the dimming dielectric layer 203 at the droplet location... The magnitude of the driving electric field is different from that of the dimming medium layer 203 outside the droplet. This causes the negative liquid crystal molecules 2033 and positive dichroic dye molecules 2032 in the dimming device 20 corresponding to the droplet to deflect at a different angle than the angle of deflection of the negative liquid crystal molecules 2033 and positive dichroic dye molecules 2032 in the dimming device 20 corresponding to the droplet. Since the deflection angles of the negative liquid crystal molecules 2033 and positive dichroic dye molecules 2032 are different in different regions, the visual color of the dimming device 20 is also different in different regions. Specifically, when no electric field is formed between the first electrode layer 104 and the second electrode layer 204, the dimming device 20 is in a normal white mode. After a vertical electric field is formed between the first electrode layer 104 and the second electrode layer 204, the electric field intensity is high in some areas of the dimming device 20 corresponding to the droplet location. The negative liquid crystal molecules 2033 and the positive dichroic dye molecules 2032 are deflected at a large angle and are basically in a flat state. The dimming device 20 corresponding to the droplet location appears darker and has low light transmittance. Meanwhile, the electric field intensity is high in some areas of the dimming device 20 outside the droplet location. The small size of the negative liquid crystal molecule 2033 and the positive dichroic dye molecule 2032 results in a small deflection angle (they may not yet be fully flat). The dimming device 20 at the location outside the droplet is not as dark as the droplet location (it is likely gray or still white), and the light transmittance is high. This allows for the rapid determination of the droplet's position within the containment cavity 103 of the microfluidic chip 10. Consequently, the movement of the droplet within the microfluidic chip 10 can be monitored quickly and accurately in real time, facilitating further manipulation or processing of the droplet and promoting the orderly conduct of subsequent experiments.

[0091] It is understood that in this embodiment Figure 9 and Figure 10The diagram only illustrates the initial state and deflection angle of the negative liquid crystal molecules 2033 and the positive dichroic dye molecules 2032, and does not represent the actual deflection angle under the driving electric field. In specific implementations, the magnitude of the deflection angle of the negative liquid crystal molecules 2033 and the positive dichroic dye molecules 2032 is related to the electric field strength. The quantity and mixing ratio of the negative liquid crystal molecules 2033 and the positive dichroic dye molecules 2032 in the diagram of this embodiment are only examples and do not represent the actual quantity set. In specific implementations, they can be set according to actual needs.

[0092] It should be noted that the first electrode layer 104 and the second electrode layer 204 in this embodiment can be formed by depositing a transparent conductive film, such as indium tin oxide (ITO) with high transmittance and high conductivity, on the surface of the first substrate 101 and the fourth substrate 202 (e.g., a transparent glass substrate), or by other fabrication methods. In this embodiment, the long axis direction of the positive dichroic dye molecules 2032 changes with the long axis direction of the negative liquid crystal molecules 2033, and always remains consistent with the long axis direction of the negative liquid crystal molecules 2033. This embodiment does not specifically limit the mixing ratio of the negative liquid crystal molecules 2033 and the positive dichroic dye molecules 2032 within the dimming medium layer 203, as long as they are uniformly mixed and all positive dichroic dye molecules 2032 can be deflected along with the negative liquid crystal molecules 2033. This embodiment does not impose specific limitations on this ratio. The third alignment film layer 207 and the fourth alignment film layer 208 in this embodiment can generally be formed by printing a polymer film (e.g., polyimide) on a glass substrate (the third substrate 201 and the fourth substrate 202 in this embodiment), but are not limited to this and can also be fabricated by other methods, which will not be described in detail in this embodiment.

[0093] In some alternative embodiments, please refer to the references. Figure 10 and Figure 11 , Figure 11 This is another structural schematic diagram of the microfluidic device provided in this embodiment of the invention. In this embodiment, the dimming medium layer 203 includes a plurality of negative liquid crystal molecules 2033 and a plurality of positive dichroic dye molecules 2032; a third alignment film layer 207 is disposed on the surface of the third substrate 201 facing the dimming medium layer 203, and a fourth alignment film layer 208 is disposed on the surface of the fourth substrate 202 facing the dimming medium layer 203; the alignment direction of the third alignment film layer 207 is the same as the alignment direction of the fourth alignment film layer 208 and both are perpendicularly aligned, wherein the initial pretilt angle α2 of the negative liquid crystal molecules 2033 is in the range of 80°-87°.

[0094] This embodiment explains that the initial pretilt angle α2 of the negative liquid crystal molecule 2033 is in the range of 80°-87°. That is, in the initial state without power, the angle α2 between the long axis of the negative liquid crystal molecule 2033 and the plane (first direction X) where the first substrate 101 is located is 80°-87°. Therefore, when monitoring the droplet position, after applying a voltage to the first electrode layer 104 and the second electrode layer 204 to form a perpendicular electric field, the negative liquid crystal molecule 2033 can deflect more quickly according to the direction of the electric field until the long axis of the negative liquid crystal molecule 2033 is perpendicular to the direction of the electric field (e.g., ...). Figure 10 (It deflects faster towards the lying position), which helps to shorten the reaction time of negative liquid crystal molecules 2033 under the drive of an electric field.

[0095] In some alternative embodiments, please refer to the references. Figure 1 , Figure 12 and Figure 13 , Figure 12 yes Figure 1 A structural diagram of the microfluidic device in its initial state before droplet position monitoring. Figure 13 yes Figure 12 A state structure diagram for droplet position monitoring is shown. In this embodiment, the dimming medium layer 203 includes polymer-dispersed liquid crystal 2034. Optionally, the dimming medium layer 203 as a whole can be a dimming glass including polymer-dispersed liquid crystal 2034 disposed between the third substrate 201 and the fourth substrate 202.

[0096] This embodiment explains that the dimming medium layer 203 of the dimming device 20 includes polymer-dispersed liquid crystal. The dimming medium layer 203 as a whole can be a dimming glass including polymer-dispersed liquid crystal 2034 disposed between the third substrate 201 and the fourth substrate 202. The polymer-dispersed liquid crystal 2034 refers to liquid crystal droplets dispersed in a polymer matrix. When no power is applied, there is a refractive index difference between the liquid crystal and the polymer, resulting in refraction in different directions at the interface, forming a hazy state. When power is applied, the liquid crystal aligns in an orderly manner along the electric field. In the design, the refractive index of the polymer is the same as that of the liquid crystal, so there is no refractive index difference between the liquid crystal and the polymer, and light does not refract, thus exhibiting a transparent state.

[0097] like Figure 12 As shown, when no electric field is formed between the first electrode layer 104 and the second electrode layer 204, the dimming medium layer 203 cannot form a regular electric field, the optical axis orientation of the liquid crystal particles in the polymer-dispersed liquid crystal 2034 is random, and it presents a disordered state. There is a refractive index difference between the liquid crystal and the polymer, which generates refraction in different directions at the interface. The dimming medium layer 203 is an opaque or semi-transparent hazy state.

[0098] like Figure 13As shown, when monitoring the position of droplet M is required, different voltage signals can be applied to the first electrode layer 104 and the second electrode layer 204 respectively (e.g., applying a 0V voltage signal to the first electrode layer 104 and a 200V voltage signal to the second electrode layer 204). This creates a sufficiently large electric field between the first electrode layer 104 and the second electrode layer 204, causing the optical axes of the liquid crystal particles in the polymer-dispersed liquid crystal 2034 to align perpendicularly to the plane of the first substrate 101 in the Z direction, i.e., consistent with the direction of the electric field. Since there is no refractive index difference between the liquid crystal and the polymer, a basically homogeneous medium is formed, light does not refract, and the dimming medium layer 203 is transparent.

[0099] Due to water polarization at the droplet location within the microfluidic chip 10, the partial pressure at the droplet location is low, while the partial pressure in the area outside the droplet (mostly air) is high. Since the intensity of the vertical electric field formed between the first electrode layer 104 and the second electrode layer 204 of the microfluidic device 000 is the same, the electric field intensity is high in some areas of the dimming device 20 corresponding to the droplet location, and low in some areas outside the droplet location. Specifically, the driving electric field of the dimming medium layer 203 at the droplet location is different from that at other locations. Specifically, when no electric field is formed between the first electrode layer 104 and the second electrode layer 204, the dimming device 20 is in an opaque or semi-transparent fog state. After a vertical electric field is formed between the electrode layers 204, the electric field strength is high in some areas of the dimming device 20 corresponding to the droplet location, and the dimming medium layer 203 of the polymer-dispersed liquid crystal 2034 exhibits stronger transparency, meaning that the light transmittance is higher at the droplet M location. In contrast, the electric field strength is low in some areas of the dimming device 20 corresponding to locations other than the droplet, and the transparency of the dimming medium layer 203 of the polymer-dispersed liquid crystal 2034 is not as obvious as at the droplet location (it may still be opaque or semi-transparent foggy), resulting in low light transmittance. Therefore, based on the difference in transmittance, the position of the droplet within the containment cavity 103 of the microfluidic chip 10 can be quickly and accurately determined. This allows for real-time monitoring of the droplet's movement within the microfluidic chip 10, facilitating further manipulation or processing of the droplet and promoting the orderly conduct of subsequent experiments.

[0100] It should be noted that in this embodiment... Figure 12 and Figure 13 The diagram only illustrates the structure of the dimming medium layer 203 including the polymer-dispersed liquid crystal 2034. In specific implementations, the structure may include, but is not limited to, the above structure, and other implementation structures may also be used. This embodiment is not limited here.

[0101] In some alternative embodiments, please refer to the references. Figure 1 , Figure 14 and Figure 15 , Figure 14 yes Figure 1 A structural diagram of the microfluidic device in its initial state before droplet position monitoring. Figure 15 yes Figure 14 This is a state structure diagram for droplet position monitoring. In this embodiment, the dimming dielectric layer 203 includes an electrochromic layer 2035. Optionally, the electrochromic layer 2035 may include a stacked electrochromic material layer 20351, an ion conductor layer 20352, and an ion storage layer 20353. The material of the electrochromic material layer 20351 may include tungsten trioxide (WO3).

[0102] This embodiment explains that the dimming medium layer 203 in the dimming device 20 can be an electrochromic layer 2035, meaning that its color can change according to different applied electric fields. In both the applied and unapplied electric states, charged ions dope and dedope the electrochromic material, causing a redox reaction that leads to a reversible change in the optical properties of the electrochromic material. This is macroscopically manifested as changes in color and transparency.

[0103] For example, the electrochromic material layer 20351 may be made of tungsten trioxide. Under the influence of an applied electric field and without an applied electric field, ions are continuously injected into and extracted from the tungsten trioxide electrochromic material layer 20351, resulting in a redox reaction, which in turn causes a reversible change in the optical properties of the tungsten trioxide layer.

[0104] like Figure 14 As shown, when no electric field is formed between the first electrode layer 104 and the second electrode layer 204, charged ions are extracted from the electrochromic material layer 20351 of tungsten trioxide and returned to the ion storage layer 20353. At this time, the dimming medium layer 203 including the electrochromic layer 2035 is transparent, that is, the light transmittance is high.

[0105] like Figure 15 As shown, when it is necessary to monitor the position of droplet M, different voltage signals can be applied to the first electrode layer 104 and the second electrode layer 204 respectively (such as applying a 0V voltage signal to the first electrode layer 104 and a 200V voltage signal to the second electrode layer 204). After a sufficiently large electric field is formed between the first electrode layer 104 and the second electrode layer 204, the charged ions in the ion storage layer 20353 are continuously injected into the electrochromic material layer 20351 of tungsten trioxide. At this time, the color of the dimming medium layer 203, including the electrochromic layer 2035, changes, possibly becoming black or dark blue, instead of the transparent state when uncharged, and the light transmittance becomes lower.

[0106] Due to water polarization at the droplet location within the microfluidic chip 10, the partial pressure at the droplet location is low, while the partial pressure in the area outside the droplet (mostly air) is high. Since the intensity of the vertical electric field formed between the first electrode layer 104 and the second electrode layer 204 of the microfluidic device 000 is the same, the electric field intensity is high in some areas of the dimming device 20 corresponding to the droplet location, and low in some areas of the dimming device 20 corresponding to locations outside the droplet. Specifically, the driving electric field of the dimming medium layer 203 at the droplet location is different from the driving electric field of the dimming medium layer 203 outside the droplet location. 4. When no electric field is formed between the first electrode layer 104 and the second electrode layer 204, the dimming device 20 is transparent. After a vertical electric field is formed between the first electrode layer 104 and the second electrode layer 204, the electric field intensity is high in some areas of the dimming device 20 corresponding to the droplet location, and the color of the dimming medium layer 203, including the electrochromic layer 2035, changes more, exhibiting a stronger opacity, that is, the light transmittance is lower at the droplet M location; while the electric field intensity is low in some areas of the dimming device 20 corresponding to locations other than the droplet, and the opacity of the dimming medium layer 203, including the electrochromic layer 2035, is not as obvious as at the droplet location (it may still be transparent or semi-transparent), and the light transmittance is slightly higher than at the droplet location. Figure 15 (Different filling patterns are used to distinguish them), so that the position of the droplet in the receiving cavity 103 of the microfluidic chip 10 can be quickly determined according to the different transmittance. This enables rapid and accurate real-time monitoring of the movement position of the droplet in the microfluidic chip 10, so as to facilitate further manipulation or processing of the droplet and facilitate the orderly conduct of subsequent experiments.

[0107] It should be noted that in this embodiment... Figure 14 and Figure 15 The diagram only illustrates the structure of the dimming medium layer 203 including the electrochromic layer 2035. In specific implementations, the structure may include, but is not limited to, the above structure, and other implementation structures may also be used. This embodiment does not limit the implementation.

[0108] In some alternative embodiments, please refer to Figure 16 , Figure 16 This is another structural schematic diagram of the microfluidic device provided in the embodiment of the present invention. In this embodiment, the first electrode layer 104 is located on the side of the first substrate 101 facing the second substrate 102, and the second electrode layer 204 is located on the side of the fourth substrate 202 facing the third substrate 203.

[0109] The second substrate 102 is attached to the side of the first substrate 101 that is away from the first substrate 101 and the third substrate 201 is attached to the side of the fourth substrate 202 that is away from the third substrate 202.

[0110] This embodiment illustrates that, taking the first substrate 101, the second substrate 102, the third substrate 201, and the fourth substrate 202 as an example arranged sequentially in the direction Z perpendicular to the plane where the first substrate 101 is located, the first electrode layer 104 can be located on the side of the first substrate 101 facing the second substrate 102, and the second electrode layer 204 can be located on the side of the fourth substrate 202 facing the third substrate 201. This allows the first electrode layer 104 to be located on the back of the microfluidic chip 10, with the first substrate 101 protecting the first electrode layer 104. The second electrode layer 204 is located inside the dimming device 20, with the fourth substrate 202 protecting the second electrode layer 204. This also reduces the distance between the first electrode layer 104 and the second electrode layer 204, preventing the thickness of the first substrate 101 and the fourth substrate 204 from affecting the electric field strength formed between the first electrode layer 104 and the second electrode layer 204, thereby helping to reduce power consumption.

[0111] In this embodiment, the microfluidic chip 10 and the dimming device 20 are stacked. The second substrate 102, facing away from the first substrate 101, and the third substrate 201, facing away from the fourth substrate 202, can be bonded together. It is understood that in this embodiment... Figure 16 Taking the example of the second substrate 102 and the third substrate 201 without any other structures between them, the microfluidic chip 10 and the dimming device 20 are stacked and fixed by bonding the side of the second substrate 102 away from the first substrate 101 and the side of the third substrate 201 away from the fourth substrate 202. In specific implementation, other structures may also be included between the second substrate 102 and the third substrate 201, such as other conductive structures, driving electrodes, etc. In this case, the side of the second substrate 102 away from the first substrate 101 and the side of the third substrate 201 away from the fourth substrate 202 do not need to be directly bonded, but can be bonded and fixed by the structure included between them. This embodiment will not be described in detail here.

[0112] It should be noted that the structure of the microfluidic device 000 in this embodiment includes, but is not limited to, those described above. Figure 16 The illustrated structure may also include structures such as the hydrophobic layer in the microfluidic chip 10 and the driving electrode that drives the droplet to move. These will not be described in detail in this embodiment. For a more detailed understanding, please refer to the structure of the microfluidic chip in the related art.

[0113] Optional, such as Figure 17 As shown, Figure 17 This is another structural schematic diagram of the microfluidic device provided in the embodiment of the present invention. In this embodiment, the sum of the thicknesses D of the second substrate 102 and the third substrate 201 is less than or equal to 0.3 mm.

[0114] This embodiment explains that the microfluidic chip 10 and the dimming device 20 are stacked together. When the second substrate 102 is attached to the side opposite to the first substrate 101 and the third substrate 201 is attached to the side opposite to the fourth substrate 202, the sum of the thicknesses D of the second substrate 102 and the third substrate 201 is less than or equal to 0.3 mm. Further optionally, the sum of the thicknesses D of the second substrate 102 and the third substrate 201 can be equal to the thickness of one first substrate 101, or the sum of the thicknesses D of the second substrate 102 and the third substrate 201 can be equal to the thickness of one fourth substrate 202. That is, by thinning the second substrate 102 and the third substrate 201 respectively, the sum of the thicknesses of the two substrates is equal to the original thickness of one substrate (such as equal to the thickness of one fourth substrate 202, or equal to the thickness of one first substrate 101). This can further reduce the distance between the first electrode layer 104 and the second electrode layer 204, which helps to minimize the loss of electric field on the glass substrate and improve the effect of droplet monitoring.

[0115] In some alternative embodiments, please refer to Figure 18 , Figure 18 This is another structural schematic diagram of the microfluidic device provided in the embodiment of the present invention. In this embodiment, the second substrate 102 is reused as the third substrate 201, the first electrode layer 104 is located on the side of the first substrate 101 facing the second substrate 102, and the second electrode layer 204 is located on the side of the fourth substrate 202 facing the second substrate 102.

[0116] This embodiment explains that when the microfluidic chip 10 and the dimming device 20 are stacked, a substrate close to each other can be reused. That is, the microfluidic device 000 in this embodiment may include only three substrates: a first substrate 101 located on the side of the receiving cavity 103 away from the dimming device 20, a fourth substrate 202 located on the side of the dimming medium layer 203 away from the microfluidic chip 10, and a second substrate 102 separating the receiving cavity 103 and the dimming medium layer 203. At this time, the first electrode layer 104 is located on the side of the first substrate 101 facing the second substrate 102, and the second electrode layer 204 is located on the side of the fourth substrate 202 facing the second substrate 102. This embodiment can monitor the position of droplets in the cavity 103 through the first electrode layer 104 and the second electrode layer 204. At the same time, the second substrate 102 can be reused as the third substrate 201, reducing the number of substrates included in the microfluidic device 000. This can further reduce the distance between the first electrode layer 104 and the second electrode layer 204, which is beneficial to further enhance the electric field strength between them and also reduce the overall thickness of the microfluidic device 000.

[0117] In some alternative embodiments, please refer to the references. Figure 19 and Figure 20 , Figure 21, Figure 19 This is another structural schematic diagram of the microfluidic device provided in the embodiments of the present invention. Figure 20 This is another structural schematic diagram of the microfluidic device provided in the embodiments of the present invention. Figure 21 yes Figure 20 A state structure diagram of the provided microfluidic device when monitoring droplet position. In this embodiment, the first electrode layer 104 is located on the side of the first substrate 101 facing the second substrate 102, and the first electrode layer 104 includes a plurality of first electrodes 1041.

[0118] This embodiment explains that when the first electrode layer 104 is located inside the microfluidic chip 10, the first electrode layer 104 can be patterned so that the first electrode layer 104 includes a plurality of first electrodes 1041. Optionally, the first electrodes 1041 can be strip-shaped or block-shaped structures, and the plurality of first electrodes 1041 can be arranged sequentially along the first direction X. In this embodiment, the first electrodes 1041 of the first electrode layer 104 can not only be used as driving electrodes to drive the movement of droplets in the receiving cavity 103, but also as electrodes that generate a monitoring electric field with the second electrode layer 204 when monitoring the position of the droplets. Specifically, when the microfluidic device 000 provided in this embodiment performs droplet movement, a driving voltage can be applied to a portion of the first electrodes 1041 in the first electrode layer 104. The movement of the droplet is based on the electrowetting effect. When the droplet covers two adjacent first electrodes 1041, the contact angle of the droplet on one of the first electrodes 1041 to which the driving voltage has been applied decreases, thereby causing the droplet to lose its balance. In order to reduce its surface energy, the droplet will move from the first electrode 1041 to which the driving voltage has been applied, thereby realizing the movement of the droplet.

[0119] When the microfluidic device 000 provided in this embodiment monitors the position of a droplet, the same driving voltage, such as a 0V voltage signal, can be applied to all the first electrodes 1041 of the first electrode layer 104, while a different voltage signal, such as a 200V voltage signal, can be applied to the second electrode layer 204. At this time, a vertical electric field is formed between all the first electrodes 1041 of the first electrode layer 104 and the second electrode layer 204. As described in the above embodiment, based on the difference in transmittance of the dimming device 20 at the location with and without droplets, the position of the droplet M can be quickly and accurately determined (e.g., ...). Figure 21 As shown, droplet M is currently located at... Figure 21 (At the location of the first electrode 1041A in the middle).

[0120] Optionally, after determining the location of the droplet M, the microfluidic device 000 provided in this embodiment can continue to monitor the location in real time during the subsequent movement of the droplet M.

[0121] like Figure 21 As shown, it is determined that droplet M is currently located at... Figure 21 At position 1041A of the first electrode, a driving voltage signal can be provided to the adjacent first electrode 1041B. The driving voltage signal is removed from the other first electrodes 1041. If the droplet M moves normally, the transmittance of the corresponding position of the dimming device 20 will inevitably change after reaching position 1041B. Therefore, by observing whether the transmittance of the dimming device 20 at position 1041B changes, it can be determined whether the droplet M has moved smoothly from position 1041A to position 1041B. If the transmittance of the dimming device 20 at position 1041B changes, it indicates that the droplet M is moving normally. If the transmittance of the dimming device 20 at position 1041B does not change, it indicates that the droplet M has not moved smoothly. In this case, the microfluidic device 000 needs to be debugged and tested. Therefore, the microfluidic device provided in this embodiment can not only quickly and accurately determine the position of the droplet by observing the change in transmittance of the dimming device 20 during the droplet's movement, but also realize real-time monitoring of the droplet's position to ensure the normal and orderly operation of the droplet in the microfluidic device 000.

[0122] Optional, such as Figure 19 and Figure 20 As shown, the microfluidic chip 10 in this embodiment may further include a first hydrophobic layer 105 and a second hydrophobic layer 106 (not filled in the figure). The first hydrophobic layer 105 may be located on the side of the first electrode layer 104 facing the second substrate 102, and the second hydrophobic layer 106 may be located on the side of the second substrate 102 facing the first substrate 101. The first hydrophobic layer 105 and the second hydrophobic layer 106 can play an insulating and protective role, while also improving the droplet travel effect.

[0123] It is understood that the structure of the microfluidic device 000 in this embodiment includes, but is not limited to, those described above. Figure 19 and Figure 20 The illustrated structure may also include other structures, which will not be elaborated in this embodiment. For details, please refer to the structure of microfluidic devices in related technologies for understanding.

[0124] In some alternative embodiments, please refer to the references. Figure 22 and Figure 23 , Figure 24 , Figure 22 This is another structural schematic diagram of the microfluidic device provided in the embodiments of the present invention. Figure 23 This is another structural schematic diagram of the microfluidic device provided in the embodiments of the present invention. Figure 24 yes Figure 23A state structure diagram of the provided microfluidic device when monitoring droplet position. In this embodiment, the microfluidic chip 10 further includes a third electrode layer 107, which is located on the side of the second substrate 102 facing the first substrate 101, and a first electrode layer 104 is located on the side of the first substrate 101 facing the second substrate 102;

[0125] The third electrode layer 107 includes a plurality of third electrodes 1071.

[0126] This embodiment explains that when the first electrode layer 104 is located on the side of the first substrate 101 facing the second substrate 102, a third electrode layer 107 for driving droplet movement can be disposed on the side of the second substrate 102 facing the first substrate 101. The third electrode layer 107 may include multiple third electrodes 1071. Optionally, the third electrodes 1071 may be strip-shaped or block-shaped, and multiple third electrodes 1071 may be arranged sequentially along the first direction X. In this embodiment, the third electrodes 1071 of the third electrode layer 107 can serve as a driving receiving cavity. The driving electrode for the movement of the droplet within 103 is used in this embodiment. Specifically, when monitoring the position of the droplet, the first electrode layer 104, which generates a monitoring electric field with the second electrode layer 204, and the third electrode layer 107, which drives the movement of the droplet, are set separately. When it is not necessary to monitor the position of the droplet, only the third electrode 1071 of the third electrode layer 107 is applied, and the droplet can move within the receiving cavity 103. When it is necessary to monitor the position of the droplet, the voltage on the third electrode layer 107 is removed, and only the voltage is applied to the first electrode layer 104 and the second electrode layer 204 to form an electric field to monitor the position of the droplet.

[0127] When the microfluidic device 000 provided in this embodiment performs droplet movement, a driving voltage can be applied to a portion of the third electrode 1071 in the third electrode layer 107. The movement of the droplet is based on the electrowetting effect. When the droplet covers two adjacent third electrodes 1071, the contact angle of the droplet on one of the third electrodes 1071 to which the driving voltage has been applied decreases, thereby causing the droplet to lose its balance. In order to reduce its surface energy, the droplet will move from the third electrode 1071 to which the voltage has not been applied to the third electrode 1071 to which the driving voltage has been applied, thereby realizing the movement of the droplet.

[0128] When the microfluidic device 000 provided in this embodiment monitors the position of a droplet, the voltage of all the third electrodes 1071 of the third electrode layer 107 can be removed, and a voltage signal, such as a 0V voltage signal, can be applied to all the first electrodes 1041 of the first electrode layer 104. Meanwhile, a different voltage signal, such as a 200V voltage signal, is applied to the second electrode layer 204. At this time, a vertical electric field is formed between all the first electrodes 1041 of the first electrode layer 104 and the second electrode layer 204. Based on the description in the above embodiment, according to the difference in transmittance of the dimming device 20 at the location with and without droplets, the position of the droplet M can be quickly and accurately determined (e.g., ...). Figure 24 As shown, droplet M is currently located at... Figure 24 (At the location of the third electrode 1071A in the middle).

[0129] Optionally, after determining the location of the droplet M, the microfluidic device 000 provided in this embodiment can continue to monitor the location in real time during the subsequent movement of the droplet M.

[0130] like Figure 24 As shown, it is determined that droplet M is currently located at... Figure 24 At position 1071A of the third electrode, a driving voltage signal can be provided to the adjacent third electrode 1071B. The driving voltage signal is removed from the other third electrodes 1071. If the droplet M moves normally, the transmittance of the dimming device 20 at the corresponding position will inevitably change after reaching position 1071B. Therefore, by observing whether the transmittance of the dimming device 20 at the corresponding position of the third electrode 1071B changes, it can be determined whether the droplet M has moved smoothly from position 1071A to position 1071B. If the transmittance of the dimming device 20 at the corresponding position of the third electrode 1071B changes, it indicates that the droplet M is moving normally. If the transmittance of the dimming device 20 at the corresponding position of the third electrode 1071B does not change, it indicates that the droplet M has not moved smoothly. In this case, the microfluidic device 000 needs to be debugged and tested. Therefore, the microfluidic device provided in this embodiment can not only quickly and accurately determine the position of the droplet by observing the change in transmittance of the dimming device 20 during the droplet's movement, but also realize real-time monitoring of the droplet's position to ensure the normal and orderly operation of the droplet in the microfluidic device 000.

[0131] Optional, such as Figure 22 and Figure 23As shown, the microfluidic chip 10 in this embodiment may further include a first hydrophobic layer 105 and a second hydrophobic layer 106 (not filled in the figure). The first hydrophobic layer 105 may be located on the side of the first electrode layer 104 facing the second substrate 102, and the second hydrophobic layer 106 may be located on the side of the second substrate 102 facing the first substrate 101. The first hydrophobic layer 105 and the second hydrophobic layer 106 can play an insulating and protective role, while also improving the droplet travel effect.

[0132] It is understood that the structure of the microfluidic device 000 in this embodiment includes, but is not limited to, those described above. Figure 22 and Figure 23 The illustrated structure may also include other structures, which will not be elaborated in this embodiment. For details, please refer to the structure of microfluidic devices in related technologies for understanding.

[0133] In some alternative embodiments, please continue to refer to Figure 22 In this embodiment, the third electrode 1071 can be a strip electrode, and multiple third electrodes 1071 are arranged along the first direction X; along the first direction X, the distance L between two adjacent third electrodes 1071 is greater than or equal to 5 μm. This embodiment explains that when the microfluidic chip 10 includes a third electrode layer 107 for driving droplet movement, the third electrode layer 107 can be patterned so that the third electrode layer 107 includes multiple strip-shaped third electrodes 1071 arranged along the droplet movement direction (first direction X). In this embodiment, setting the distance L between two adjacent third electrodes 1071 along the first direction X to be greater than or equal to 5 μm can avoid the spacing between the third electrodes 1071 being too small, which is beneficial to reducing the difficulty of the process. Furthermore, since driving droplet movement generally requires a high driving voltage, setting the distance L between two adjacent third electrodes 1071 to be greater than or equal to 5 μm avoids the possibility of high voltage breakdown caused by the spacing between adjacent third electrodes 1071 being too close, thereby helping to ensure product yield.

[0134] It is understood that, in this embodiment, the distance L between two adjacent third electrodes 1071 can be understood as the distance between the edge 1071A0 of one third electrode 1071A closest to another third electrode 1071B and the edge 1071B0 of another third electrode 1071B closest to the third electrode 1071A in the first direction X. Therefore, in this embodiment, the distance L between two adjacent third electrodes 1071 can be understood as the length of the gap between two adjacent third electrodes 1071.

[0135] In some alternative embodiments, please refer to the references. Figure 25 , Figure 26 and Figure 27 , Figure 28 , Figure 25This is another structural schematic diagram of the microfluidic device provided in the embodiments of the present invention. Figure 26 This is another structural schematic diagram of the microfluidic device provided in the embodiments of the present invention. Figure 27 This is another structural schematic diagram of the microfluidic device provided in the embodiments of the present invention. Figure 28 yes Figure 25 A state structure diagram of the provided microfluidic device during droplet position monitoring. In this embodiment, the dimming device 20 further includes a fourth electrode layer 209, which is located on the side of the dimming dielectric layer 203 away from the second electrode layer 204. Optionally, this embodiment takes the fourth electrode layer 209 located on the side of the third substrate 201 facing the fourth substrate 202 as an example. In specific implementation, the fourth electrode layer 209 can also be located in other positions, and the fourth electrode layer 209 includes a plurality of fourth electrodes 2091.

[0136] In the direction Z perpendicular to the plane of the first substrate 101, a third electrode 1071 and a fourth electrode 2091 completely overlap; a third electrode 1071 and a fourth electrode 2091 at the same position are electrically connected.

[0137] This embodiment explains that the dimming device 20 may further include a fourth electrode layer 209 located on the third substrate 201. It is understood that this embodiment uses the second substrate 102 and the third substrate 201 as examples for illustration; in specific implementations, the second substrate 102 and the third substrate 201 may be reused. In this embodiment, the fourth electrode layer 209 is disposed on the side of the dimming dielectric layer 203 away from the second electrode layer 204; optionally, such as... Figures 25-27 As shown, the fourth electrode layer 209 can be located on the side of the third substrate 201 facing the fourth substrate 202. In specific implementations, the fourth electrode layer 209 can also be located in other positions. This embodiment is not limited, as long as the fourth electrode layer 209 is disposed on the side of the dimming medium layer 203 away from the second electrode layer 204. The fourth electrode layer 209 in this embodiment includes a plurality of fourth electrodes 2091. The fourth electrodes 2091 can be strip-shaped or block-shaped structures, and the plurality of fourth electrodes 2091 can be arranged sequentially along the first direction X. In the direction Z perpendicular to the plane where the first substrate 101 is located, a third electrode 1071 and a fourth electrode 2091 completely overlap. Optionally, the complete overlap of a third electrode 1071 and a fourth electrode 2091 can be in the direction Z perpendicular to the plane where the first substrate 101 is located, where a third electrode 1071 and a fourth electrode 2091 have the same shape and equal area (e.g., ...). Figure 25 (As shown), or in the direction Z perpendicular to the plane of the first substrate 101, a third electrode 1071 covers a fourth electrode 2091 (as shown). Figure 26(As shown), or in a direction Z perpendicular to the plane of the first substrate 101, a fourth electrode 2091 covers a third electrode 1071 (as shown). Figure 27 As shown in the figure, it is only necessary to satisfy that, in the direction Z perpendicular to the plane where the first substrate 101 is located, one third electrode 1071 and one fourth electrode 2091 completely overlap, rather than one third electrode 1071 and two fourth electrodes 2091 overlapping, or two third electrodes 1071 and one fourth electrode 2091 overlapping. In this embodiment, one third electrode 1071 and one fourth electrode 2091 at the same position are electrically connected (not shown in the figure; the electrical connection can be achieved through an external signal line or by drilling holes in the glass substrate; this embodiment is not limited to this). That is, the same voltage signal is applied to one third electrode 1071 and one fourth electrode 2091 at the same position. In this embodiment, the electric field driving the liquid crystal deflection in the dimming medium layer 203 is the electric field generated between the fourth electrode layer 209 and the second electrode layer 204. Since the fourth electrode layer 209 is closer to the second electrode layer 204 than the first electrode layer 104, it can provide better driving capability for liquid crystal deflection, which is beneficial to improving the sensitivity of the dimming device 20 to changes in transmittance.

[0138] like Figure 28 As shown, when the microfluidic device 000 provided in this embodiment performs droplet movement, a driving voltage can be applied to a portion of the third electrode 1071 in the third electrode layer 107. The movement of the droplet is based on the electrowetting effect. When the droplet covers two adjacent third electrodes 1071, the contact angle of the droplet on one of the third electrodes 1071 to which the driving voltage has been applied decreases, thereby causing the droplet to lose its balance. In order to reduce its surface energy, the droplet will move from the third electrode 1071 to which the voltage has not been applied to the third electrode 1071 to which the driving voltage has been applied, thereby realizing the movement of the droplet.

[0139] When the microfluidic device 000 provided in this embodiment monitors the position of a droplet, the voltage of all the third electrodes 1071 of the third electrode layer 107 can be removed, and a voltage signal, such as a 0V voltage signal, can be applied to all the first electrodes 1041 of the first electrode layer 104. Meanwhile, a different voltage signal, such as a 200V voltage signal, is applied to the second electrode layer 204. At this time, a vertical electric field is formed between all the first electrodes 1041 of the first electrode layer 104 and the second electrode layer 204. Based on the description in the above embodiment, according to the difference in transmittance of the dimming device 20 at the location with and without droplets, the position of the droplet M can be quickly and accurately determined (e.g., ...). Figure 28 As shown, droplet M is currently located at... Figure 28 (At the location of the third electrode 1071A in the middle).

[0140] Optionally, after determining the location of the droplet M, the microfluidic device 000 provided in this embodiment can continue to monitor the location in real time during the subsequent movement of the droplet M.

[0141] like Figure 28 As shown, it is determined that droplet M is currently located at... Figure 28 The transmittance at position 1071A (i.e., position 2091A) differs from that at other positions. Therefore, a driving voltage signal can be provided to the adjacent third electrode 1071B, while the driving voltage signals to the other third electrodes 1071 are removed. Since one third electrode 1071 at the same position is electrically connected to one fourth electrode 2091, meaning the same voltage signal is applied to both, if the droplet M travels normally, upon reaching position 1071B, the corresponding position of the dimming device 20 will... The transmittance at the fourth electrode 2091B will inevitably change. Therefore, by observing whether the transmittance of the dimming device 20 at the corresponding position of the fourth electrode 2091B changes, it can be determined whether the droplet M has successfully moved from the position of the third electrode 1071A to the position of the third electrode 1071B. If the transmittance of the dimming device 20 at the corresponding position of the fourth electrode 2091B changes, it indicates that the droplet M is moving normally. If the transmittance of the dimming device 20 at the corresponding position of the fourth electrode 2091B does not change, it indicates that the droplet M has not moved smoothly, and the microfluidic device 000 needs to be debugged and tested. Therefore, this embodiment provides a microfluidic device that can not only quickly and accurately determine the position of the droplet by observing the change in the transmittance of the dimming device 20 during the droplet's movement, but also realize real-time monitoring of the droplet position to ensure the normal and orderly operation of the droplet in the microfluidic device 000.

[0142] Optional, such as Figure 29 As shown, Figure 29 This is another structural schematic diagram of the microfluidic device provided in the embodiment of the present invention. When the fourth electrode layer 209 is provided on the side of the third substrate 201 facing the fourth substrate 202 in this embodiment, the second substrate 102 can also be reused with the third substrate 201, which is beneficial to reduce the thickness of the device.

[0143] Optional, such as Figure 30 As shown, Figure 30This is another structural schematic diagram of the microfluidic device provided in this embodiment of the invention. In this embodiment, the fourth electrode layer 209 can also be located on the side of the third substrate 201 away from the fourth substrate 202. In this case, the stacked arrangement of the microfluidic chip 10 and the dimming device 20 can be achieved by fixing the lower surface of the fourth electrode layer 209 to the side of the third substrate 201 away from the fourth substrate 202, and fixing the upper surface of the fourth electrode layer 209 to the side of the second substrate 102 away from the first substrate 101.

[0144] Optional, such as Figure 31 As shown, Figure 31 This is another structural schematic diagram of the microfluidic device provided in the embodiment of the present invention. When the second substrate 102 and the third substrate 201 are reused in this embodiment, the third electrode layer 107 can also be reused as the fourth electrode layer 209. At this time, the fourth electrode layer 209 is located on the side of the third substrate 201 away from the fourth substrate 202, which helps to further reduce the number of electrode layers in the microfluidic device 000 and reduce the overall thickness of the microfluidic device.

[0145] In some alternative embodiments, please refer to the references. Figure 32 , Figure 33 , Figure 32 This is another structural schematic diagram of the microfluidic device provided in the embodiments of the present invention. Figure 33 yes Figure 32 A state structure diagram of the provided microfluidic device when monitoring droplet position. In this embodiment, the first electrode layer 104 is located on the side of the first substrate 101 facing the second substrate 102. The first electrode layer 104 includes a plurality of first electrodes 1041. That is, when the first electrode layer 104 in the microfluidic chip 10 is used as both a detection electrode for determining the droplet position and a driving electrode for driving the droplet to move, a fourth electrode layer 209 can be provided on the side of the third substrate 201 facing the fourth substrate 202. In the direction Z perpendicular to the plane where the first substrate 101 is located, a first electrode 1041 and a fourth electrode 2091 completely overlap; a first electrode 1041 and a fourth electrode 2091 at the same position are electrically connected.

[0146] This embodiment explains that the dimming device 20 may further include a fourth electrode layer 209 located on the third substrate 201. It is understood that this embodiment uses the second substrate 102 and the third substrate 201 as examples for illustration; in specific implementations, the second substrate 102 and the third substrate 201 may be reused. In this embodiment, the fourth electrode layer 209 is disposed on the side of the dimming dielectric layer 203 away from the second electrode layer 204; optionally, such as... Figure 32As shown, the fourth electrode layer 209 can be located on the side of the third substrate 201 facing the fourth substrate 202. In specific implementations, the fourth electrode layer 209 can also be located in other positions. This embodiment is not limited, as long as the fourth electrode layer 209 is disposed on the side of the dimming medium layer 203 away from the second electrode layer 204. The fourth electrode layer 209 in this embodiment includes a plurality of fourth electrodes 2091. The fourth electrodes 2091 can be strip-shaped or block-shaped structures, and the plurality of fourth electrodes 2091 can be arranged sequentially along the first direction X. In the direction Z perpendicular to the plane where the first substrate 101 is located, a first electrode 1041 and a fourth electrode 2091 completely overlap. Optionally, the complete overlap of a first electrode 1041 and a fourth electrode 2091 can be in the direction Z perpendicular to the plane where the first substrate 101 is located, where a first electrode 1041 and a fourth electrode 2091 have the same shape and equal area (e.g., ...). Figure 32 As shown in the figure, in the direction Z perpendicular to the plane of the first substrate 101, one first electrode 1041 covers one fourth electrode 2091 (not shown in the figure), or in the direction Z perpendicular to the plane of the first substrate 101, one fourth electrode 2091 covers one first electrode 1041 (not shown in the figure). It is only necessary that in the direction Z perpendicular to the plane of the first substrate 101, one first electrode 1041 and one fourth electrode 2091 completely overlap, rather than one first electrode 1041 overlapping with two fourth electrodes 2091, or two first electrodes 1041 overlapping with one fourth electrode 2091. In this embodiment, one first electrode 1041 and one fourth electrode 2091 at the same location are electrically connected (not shown in the figure; electrical connection can be achieved through an external signal line or other methods, which are not limited in this embodiment). That is, the same voltage signal is applied to one first electrode 1041 and one fourth electrode 2091 at the same location. In this embodiment, the electric field that drives the liquid crystal deflection in the dimming medium layer 203 is the electric field generated between the fourth electrode layer 209 and the second electrode layer 204. Since the fourth electrode layer 209 is closer to the second electrode layer 204 than the first electrode layer 104, it can provide better driving capability for liquid crystal deflection, which is beneficial to improving the sensitivity of the dimming device 20 to changes in transmittance.

[0147] like Figure 33As shown, when the microfluidic device 000 provided in this embodiment performs droplet movement, a driving voltage can be applied to a portion of the first electrodes 1041 in the first electrode layer 104. The movement of the droplet is based on the electrowetting effect. When the droplet covers two adjacent first electrodes 1041, the contact angle of the droplet on one of the first electrodes 1041 to which the driving voltage has been applied decreases, thereby causing the droplet to lose its balance. In order to reduce its surface energy, the droplet will move from the first electrode 1041 to which the driving voltage has been applied, thereby realizing the movement of the droplet.

[0148] When the microfluidic device 000 provided in this embodiment monitors the position of a droplet, a voltage signal, such as a 0V voltage signal, can be applied to all the first electrodes 1041 of the first electrode layer 104, while a different voltage signal, such as a 200V voltage signal, can be applied to the second electrode layer 204. At this time, a perpendicular electric field is formed between all the first electrodes 1041 of the first electrode layer 104 and the second electrode layer 204. As described in the above embodiment, based on the difference in transmittance of the dimming device 20 at the location with and without droplets, the position of the droplet M can be quickly and accurately determined (e.g., ...). Figure 33 As shown, droplet M is currently located at... Figure 33 (At the location of the first electrode 1041A in the middle).

[0149] Optionally, after determining the location of the droplet M, the microfluidic device 000 provided in this embodiment can continue to monitor the location in real time during the subsequent movement of the droplet M.

[0150] like Figure 33 As shown, it is determined that droplet M is currently located at... Figure 33The transmittance at position 1041A (i.e., position 2091A) differs from that at other positions. Therefore, a driving voltage signal can be provided to the adjacent first electrode 1041B, while the driving voltage signals to the other first electrodes 1041 are removed. Since one first electrode 1041 at the same position is electrically connected to one fourth electrode 2091, meaning the same voltage signal is applied to both, if the droplet M travels normally, upon reaching position 1041B, the corresponding position of the dimming device 20 will... The transmittance at the fourth electrode 2091B will inevitably change. Therefore, by observing whether the transmittance of the dimming device 20 at the corresponding position of the fourth electrode 2091B changes, it can be determined whether the droplet M has moved smoothly from the position of the first electrode 1041A to the position of the first electrode 1041B. If the transmittance of the dimming device 20 at the corresponding position of the fourth electrode 2091B changes, it indicates that the droplet M is moving normally. If the transmittance of the dimming device 20 at the corresponding position of the fourth electrode 2091B does not change, it indicates that the droplet M has not moved smoothly, and the microfluidic device 000 needs to be debugged and tested. Therefore, this embodiment provides a microfluidic device that can not only quickly and accurately determine the position of the droplet by observing the change in the transmittance of the dimming device 20 during the droplet's movement, but also realize real-time monitoring of the droplet position to ensure the normal and orderly operation of the droplet in the microfluidic device 000.

[0151] Optional, such as Figure 34 As shown, Figure 34 This is another structural schematic diagram of the microfluidic device provided in the embodiment of the present invention. In this embodiment, the first electrode layer 104 is located on the side of the first substrate 101 facing the second substrate 102. The first electrode layer 104 includes a plurality of first electrodes 1041. When the fourth electrode layer 209 is provided on the side of the third substrate 201 facing the fourth substrate 202, the second substrate 102 can also be reused with the third substrate 201, which is beneficial to reduce the thickness of the device.

[0152] In some alternative embodiments, please refer to the references. Figure 35 and Figure 36 , Figure 35 This is another structural schematic diagram of the microfluidic device provided in the embodiments of the present invention. Figure 36 yes Figure 35 A state structure diagram of the provided microfluidic device when monitoring droplet position. In this embodiment, a plurality of barrier members 200 are disposed between the third substrate 201 and the fourth substrate 202, and the orthogonal projection of the barrier member 200 onto the third substrate 201 is located between the orthogonal projections of two adjacent fourth electrodes 2091 onto the third substrate 201.

[0153] This embodiment explains that the dimming dielectric layer 203 may include multiple barrier elements 200. Optionally, the material used to make the barrier elements 200 can be any material with light-shielding properties, such as the same material as the black matrix in the display panel. In this embodiment, the orthographic projection of the barrier element 200 onto the third substrate 201 is located between the orthographic projections of two adjacent fourth electrodes 2091 onto the third substrate 201. This avoids mutual interference between the dimming dielectric layer 203 at the droplet location and the dimming dielectric layer 203 at other locations. Consequently, there is a more significant difference in transmittance between the dimming device 20 at the droplet location and the dimming device 20 at other locations, making the results easier to obtain through visual observation. Furthermore, when the dimming device 20 of this embodiment includes a fourth electrode layer 209, and the fourth electrode layer 209 includes a plurality of fourth electrodes 2091, the barrier 200 located between the orthogonal projections of two adjacent fourth electrodes 2091 onto the third substrate 201 can also prevent the energized fourth electrodes 2091 from interfering with the unenergized fourth electrodes 2091, thereby improving the effect of the dimming device 20 in real-time monitoring of droplet position based on the droplet's movement process in the microfluidic chip 10.

[0154] In some alternative embodiments, please refer to the references. Figures 1-36 , Figure 37 , Figure 37 This is a flowchart of a method for using a microfluidic device provided in an embodiment of the present invention. The method provided in this embodiment is at least used by the microfluidic device 000 in the above embodiment to detect the position of droplet M.

[0155] The usage method of this embodiment includes:

[0156] S10: A droplet M is placed in the cavity 103 of the microfluidic chip 10 to provide a first voltage signal V1 to the first electrode layer 104 and a second voltage signal V2 to the second electrode layer 204, so that an electric field is formed between the first electrode layer 104 and the second electrode layer 204. Optionally, the first voltage signal V1 can be a 0V voltage signal, and the second voltage signal V2 can be a positive voltage signal, such as 200V, 100V, 150V, etc., or the first voltage signal V1 and the second voltage signal V2 can be other voltage values. This embodiment does not make specific limitations, as long as the first voltage signal V1 and the second voltage signal V2 are different and a vertical electric field can be formed between the first electrode layer 104 and the second electrode layer 204.

[0157] S11: Under the electric field formed by the first electrode layer 104 and the second electrode layer 204, the transmittance at the location of the droplet M in the dimming device 20 is different from the transmittance at other locations in the dimming device 20, thus determining the location of the droplet M.

[0158] This embodiment explains the usage of the microfluidic device 000. The microfluidic device 000 provided in the above embodiment can detect and determine the specific position of the droplet M in the receiving cavity 103. When the droplet M is at a certain position in the receiving cavity 103 of the microfluidic chip 10, an electric field is formed between the first electrode layer 104 and the second electrode layer 204. Due to water polarization at the droplet's location, the partial pressure at the droplet's location in the microfluidic chip 10 is low, while the partial pressure in the area outside the droplet (mostly air) is high. Since the driving electric field strength between the first electrode layer 104 and the second electrode layer 204 of the microfluidic device 000 as a whole is the same, the electric field strength in some areas of the dimming device 20 corresponding to the position of the droplet M is high, while the electric field strength in some areas of the dimming device 20 corresponding to positions outside the droplet M is low. That is, the driving electric field strength of the dimming medium layer 203 at the position of the droplet M is low. The magnitude of the driving electric field is different from that of the dimming medium layer 203 at a location other than the droplet M. This results in a difference in the transmittance of the dimming medium layer 203 at the location of the droplet compared to the transmittance at a location other than the droplet. This difference in transmittance is generally reflected in the visual effect as a difference in the color. Based on the different colors in different areas of the dimming device 20, the position of the droplet within the containment cavity 103 of the microfluidic chip 10 can be quickly determined. This allows for rapid and accurate real-time monitoring of the droplet's movement within the microfluidic chip 10, facilitating further manipulation or processing of the droplet and promoting the orderly conduct of subsequent experiments.

[0159] In some alternative embodiments, please refer to the references. Figures 19-21 , Figures 32-34 , Figure 38 , Figure 38 This is a flowchart illustrating another method of using the microfluidic device provided in this embodiment of the invention. The method provided in this embodiment is at least used by the microfluidic device 000 in the above embodiments to perform real-time monitoring of the droplet M position. The method provided in this embodiment includes:

[0160] S20: A droplet M is disposed within the cavity 103 of the microfluidic chip 10, providing a first voltage signal V1 to the first electrode layer 104 and a second voltage signal V2 to the second electrode layer 204, thereby forming an electric field between the first electrode layer 104 and the second electrode layer 204. Optionally, the first voltage signal V1 can be a 0V voltage signal, and the second voltage signal V2 can be a positive voltage signal, such as 200V, 100V, 150V, etc., or the first voltage signal V1 and the second voltage signal V2 can be other voltage values. This embodiment does not impose specific limitations, as long as the first voltage signal V1 and the second voltage signal V2 are different, and a perpendicular electric field can be formed between the first electrode layer 104 and the second electrode layer 204. Optionally, in this embodiment, the first electrode layer 104 includes multiple first electrodes 1041, which are used as driving electrodes for the droplet M.

[0161] S21: Under the electric field formed by the first electrode layer 104 and the second electrode layer 204, the transmittance at the location of the droplet M in the dimming device 20 is different from the transmittance at other locations in the dimming device 20, thus determining the location of the droplet M. The first electrode 1041 corresponding to the location of the droplet M is the A-th first electrode 1041A; where A is a positive integer.

[0162] S22: Provide a driving voltage signal for the (A+1)th first electrode 1041B, and provide floating voltage signals for the remaining first electrodes 1041; it can be understood that the floating voltage signal can be understood as not providing any voltage signal, that is, the driving voltage signals of all first electrodes 1041 except for the (A+1)th first electrode 1041B are removed, wherein the (A+1)th first electrode 1041B is adjacent to the Ath first electrode 1041A, that is, there are no other first electrodes 1041 between the (A+1)th first electrode 1041B and the Ath first electrode 1041A;

[0163] S23: If the transmittance of the dimming device 20 at the position corresponding to the (A+1)th first electrode 1041B changes, the droplet M moves from the Ath first electrode 1041A to the (A+1)th first electrode 1041B.

[0164] S24: If the transmittance of the dimming device 20 at the position corresponding to the (A+1)th first electrode 1041B does not change, then the droplet M remains at the Ath first electrode 1041A.

[0165] This embodiment explains that when the first electrode 1041 of the first electrode layer 104 is used not only as a driving electrode for driving the movement of the droplet in the receiving cavity 103, but also as an electrode that generates a monitoring electric field with the second electrode layer 204 when monitoring the position of the droplet, it is possible to determine that the droplet M is currently located at... Figure 21After the Ath first electrode 1041A is positioned, a driving voltage signal is further provided to the (A+1)th first electrode 1041B adjacent to the Ath first electrode 1041A. The driving voltage signal is removed from the remaining first electrodes 1041. Since the droplet M will travel normally and reach the position of the (A+1)th first electrode 1041B, the transmittance of the dimming device 20 at the corresponding position will inevitably change. Therefore, at this time, it is only necessary to observe the transmittance of the dimming device 20 at the position corresponding to the (A+1)th first electrode 1041B. Whether the transmittance changes determines whether the droplet M has successfully moved from position A of the first electrode 1041A to position A+1 of the first electrode 1041B. If the transmittance of the dimming device 20 at position A+1 of the first electrode 1041B changes, it indicates that the droplet M is moving normally. If the transmittance of the dimming device 20 at position A+1 of the first electrode 1041B does not change, it indicates that the droplet M has not moved smoothly, and the microfluidic device 000 needs to be debugged and tested. Therefore, the method of using the microfluidic device provided in this embodiment can not only quickly and accurately determine the position of the droplet M by observing the change in the transmittance of the dimming device 20 during the movement of the droplet M, but also further realize real-time monitoring of the position of the droplet M to ensure the normal and orderly operation of the droplet in the microfluidic device 000.

[0166] In some alternative embodiments, please refer to the references. Figures 22-31 , Figure 39 , Figure 39 This is a flowchart illustrating another method of using the microfluidic device provided in this embodiment of the invention. The method provided in this embodiment is at least used by the microfluidic device 000 in the above embodiments to perform real-time monitoring of the droplet M position. The method provided in this embodiment includes:

[0167] S30: A droplet M is placed in the cavity 103 of the microfluidic chip 10 to provide a first voltage signal V1 to the first electrode layer 104 and a second voltage signal V2 to the second electrode layer 204, so that an electric field is formed between the first electrode layer 104 and the second electrode layer 204. Optionally, the first voltage signal V1 can be a 0V voltage signal, and the second voltage signal V2 can be a positive voltage signal, such as 200V, 100V, 150V, etc., or the first voltage signal V1 and the second voltage signal V2 can be other voltage values. This embodiment does not make specific limitations, as long as the first voltage signal V1 and the second voltage signal V2 are different and a vertical electric field can be formed between the first electrode layer 104 and the second electrode layer 204. Optionally, in this embodiment, the microfluidic chip 10 further includes a third electrode layer 107. The third electrode layer 107 is located on the side of the second substrate 102 facing the first substrate 101, and the first electrode layer 104 is located on the side of the first substrate 101 facing the second substrate 102. The third electrode layer 107 includes a plurality of third electrodes 1071, which are used as driving electrodes for the droplet M.

[0168] S31: Under the electric field formed by the first electrode layer 104 and the second electrode layer 204, the transmittance at the location of the droplet M in the dimming device 20 is different from the transmittance at other locations in the dimming device 20, thus determining the location of the droplet M. The third electrode 1071 corresponding to the location of the droplet M is the Bth third electrode 1071A; where B is a positive integer.

[0169] S32: Provide a driving voltage signal for the (B+1)th third electrode 1071B, and provide floating voltage signals for the remaining third electrodes 1071; it can be understood that the floating voltage signal can be understood as not providing any voltage signal, that is, all third electrodes 1071 except the (B+1)th third electrode 1071B are removed from the driving voltage signal, wherein the (B+1)th third electrode 1071B is adjacent to the Bth third electrode 1071A, that is, there are no other third electrodes 1071 between the (B+1)th third electrode 1071B and the Bth third electrode 1071A;

[0170] S33: If the transmittance of the dimming device 20 at the position corresponding to the (B+1)th third electrode 1071B changes, the droplet M moves from the Bth third electrode 1071A to the (B+1)th third electrode 1071B.

[0171] S34: If the transmittance of the dimming device 20 at the position corresponding to the (B+1)th third electrode 1071B does not change, then the droplet M remains at the Bth third electrode 1071A.

[0172] This embodiment explains that when the microfluidic chip 10 is additionally provided with a third electrode layer 107 as a driving electrode for the movement of droplets within the drive cavity 103, and the third electrode layer 107 includes multiple third electrodes 1071, it is possible to determine that the droplet M is located at this time... Figure 24 Position B of the third electrode 1071A can provide a driving voltage signal to the (B+1)th third electrode 1071B adjacent to it. The driving voltage signal is removed from the remaining third electrodes 1071. Since the droplet M will travel normally and reach the (B+1)th third electrode 1071B, the transmittance at the corresponding position of the dimming device 20 will inevitably change. Therefore, at this time, it is only necessary to observe the transmittance of the dimming device 20 at the position corresponding to the (B+1)th third electrode 1071B. By checking whether the transmittance changes, it can be determined whether the droplet M has successfully moved from the position of the Bth third electrode 1071A to the position of the (B+1)th third electrode 1071B. If the transmittance of the dimming device 20 at the position corresponding to the (B+1)th third electrode 1071B changes, it indicates that the droplet M is moving normally. If the transmittance of the dimming device 20 at the position corresponding to the (B+1)th third electrode 1071B does not change, it indicates that the droplet M has not moved smoothly, and the microfluidic device 000 needs to be debugged and tested. Therefore, the method of using the microfluidic device provided in this embodiment can not only quickly and accurately determine the position of the droplet by checking the change in the transmittance of the dimming device 20 during the droplet's movement, but also realize real-time monitoring of the droplet position to ensure the normal and orderly operation of the droplet in the microfluidic device 000.

[0173] As can be seen from the above embodiments, the microfluidic device and its usage method provided by the present invention achieve at least the following beneficial effects:

[0174] In the microfluidic device provided by the present invention, a microfluidic chip and a dimming device are stacked. The microfluidic chip is used as a carrier for droplet manipulation, and the droplets can perform a series of operations in the microfluidic chip, such as moving, separating, and mixing. The dimming device is used to monitor the position of the droplets in the microfluidic chip in real time. When a droplet moves within the containment cavity of a microfluidic chip, different voltage signals can be applied to the first and second electrode layers, creating a driving electric field between them. Due to water polarization at the droplet's location, the driving electric field of the dimming medium layer at the droplet's location differs from that at other locations. This results in a difference in transmittance between the dimming medium layer at the droplet's location and that at other locations. This difference in transmittance is visually reflected as a difference in color. By observing the color differences in different areas of the dimming device, the droplet's position within the microfluidic chip's containment cavity can be quickly determined. This allows for rapid and accurate real-time monitoring of the droplet's movement within the chip, facilitating further manipulation or processing and ensuring the orderly conduct of subsequent experiments.

[0175] While specific embodiments of the invention have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of the invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. A microfluidic device, characterized in that, The microfluidic chip and the light modulation device are stacked. The microfluidic chip comprises a first substrate and a second substrate arranged oppositely, and a containing cavity is arranged between the first substrate and the second substrate; the microfluidic chip comprises a first electrode layer, and the first electrode layer is located on a side of the containing cavity away from the light modulation device; The light modulation device comprises a third substrate and a fourth substrate arranged oppositely, and a light modulation medium layer is arranged between the third substrate and the fourth substrate; the light modulation device comprises a second electrode layer, and the second electrode layer is located on a side of the light modulation medium layer away from the microfluidic chip; The microfluidic chip further comprises a third electrode layer, and the third electrode layer is located on a side of the second substrate facing the first substrate; the first electrode layer is located on a side of the first substrate facing the second substrate; The third electrode layer comprises a plurality of third electrodes. The light modulation medium layer comprises a plurality of positive liquid crystal molecules and a plurality of positive dichroic dye molecules; 2. The microfluidic device of claim 1, wherein, A first alignment film layer is arranged on a surface of the third substrate facing the light modulation medium layer, and a second alignment film layer is arranged on a surface of the fourth substrate facing the light modulation medium layer; The alignment direction of the first alignment film layer is the same as the alignment direction of the second alignment film layer, and both are horizontal alignment. The initial pre-tilt angle of the positive liquid crystal molecules ranges from 3° to 10°.

3. The microfluidic device of claim 2, wherein, The light modulation medium layer comprises a plurality of negative liquid crystal molecules and a plurality of positive dichroic dye molecules; 4. The microfluidic device of claim 1, wherein, A third alignment film layer is arranged on a surface of the third substrate facing the light modulation medium layer, and a fourth alignment film layer is arranged on a surface of the fourth substrate facing the light modulation medium layer; The alignment direction of the third alignment film layer is the same as the alignment direction of the fourth alignment film layer, and both are vertical alignment. The initial pre-tilt angle of the negative liquid crystal molecules ranges from 80° to 87°.

5. The microfluidic device of claim 4, wherein, The light modulation medium layer comprises a polymer dispersed liquid crystal.

6. The microfluidic device of claim 1, wherein, The light modulation medium layer comprises an electrochromic layer.

7. The microfluidic device of claim 1, wherein, The first electrode layer is located on a side of the first substrate facing the second substrate, and the second electrode layer is located on a side of the fourth substrate facing the third substrate; 8. The microfluidic device of claim 1, wherein, A side of the second substrate away from the first substrate is arranged in abutment with a side of the third substrate away from the fourth substrate. The sum of the thicknesses of the second substrate and the third substrate is less than or equal to 0.3 mm.

9. The microfluidic device of claim 8, wherein, The second substrate is multiplexed as the third substrate, the first electrode layer is located on a side of the first substrate facing the second substrate, and the second electrode layer is located on a side of the fourth substrate facing the second substrate.

10. The microfluidic device of claim 1, wherein, The first electrode layer comprises a plurality of first electrodes.

11. The microfluidic device of claim 1, wherein, The light modulation device further comprises a fourth electrode layer, and the fourth electrode layer is located on a side of the light modulation medium layer away from the second electrode layer; the fourth electrode layer comprises a plurality of fourth electrodes; 12. The microfluidic device of claim 1, wherein, In a direction perpendicular to the plane in which the first substrate is located, one third electrode and one fourth electrode completely overlap; one third electrode and one fourth electrode at the same position are electrically connected.

13. The microfluidic device according to claim 12, wherein ​ The fourth electrode layer is located on a side of the third substrate facing the fourth substrate, or the fourth electrode layer is located on a side of the third substrate facing away from the fourth substrate.

14. The microfluidic device of claim 12, wherein, A plurality of barriers are arranged between the third substrate and the fourth substrate, and a projection of the barrier on the third substrate is located between projections of two adjacent fourth electrodes on the third substrate.

15. The microfluidic device of claim 1, wherein, The third electrode is a strip-shaped electrode, and a plurality of third electrodes are arranged along a first direction. The distance between two adjacent third electrodes along the first direction is greater than or equal to 5 μm.

16. A method of using a microfluidic device, the method comprising: The use method is used for detecting the position of a droplet in the microfluidic device of any one of claims 1-15. The use method comprises: A droplet is arranged in the accommodation cavity of the microfluidic chip, a first voltage signal is provided for the first electrode layer, a second voltage signal is provided for the second electrode layer, and an electric field is formed between the first electrode layer and the second electrode layer. Under the electric field formed by the first electrode layer and the second electrode layer, the transmittance of the position of the droplet of the light modulation device is different from the transmittance of other positions of the light modulation device, and the position of the droplet is determined.

17. The method of use of claim 16, wherein, The use method further comprises: The first electrode layer comprises a plurality of first electrodes, and the first electrodes are used as droplet driving electrodes; The first electrode corresponding to the position of the droplet is the A-th first electrode; wherein A is a positive integer; A driving voltage signal is provided for the A+1-th first electrode, and a floating voltage signal is provided for the remaining first electrodes; the A+1-th first electrode is adjacent to the A-th first electrode; At this time, if the transmittance of the light modulation device at the position corresponding to the A+1-th first electrode changes, the droplet moves from the A-th first electrode to the A+1-th first electrode; If the transmittance of the light modulation device at the position corresponding to the A+1-th first electrode does not change, the droplet remains at the A-th first electrode.

18. The method of use of claim 16, wherein, The use method further comprises: The microfluidic chip further comprises a third electrode layer, the third electrode layer is located on a side of the second substrate facing the first substrate, the first electrode layer is located on a side of the first substrate facing the second substrate, the third electrode layer comprises a plurality of third electrodes, and the third electrodes are used as droplet driving electrodes; The third electrode corresponding to the position of the droplet is the B-th third electrode; wherein B is a positive integer; A driving voltage signal is provided for the B+1-th third electrode, and a floating voltage signal is provided for the remaining third electrodes; the B+1-th third electrode is adjacent to the B-th third electrode; At this time, if the transmittance of the light modulation device at the position corresponding to the B+1-th third electrode changes, the droplet moves from the B-th third electrode to the B+1-th third electrode; If the transmittance of the light modulation device at the position corresponding to the B+1-th third electrode does not change, the droplet remains at the B-th third electrode.

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