Liquid selective driving method based on optical virtual electric wetting channel

Abstract

The present application relates to a kind of liquid selective driving method based on optical virtual electric wetting channel, comprising the following steps: according to the position of the droplet to be driven, size and preset moving path, corresponding projection pattern is acquired, and projection pattern is projected on single plane photoelectric wetting chip;Projection pattern includes bright stripe, color same drive dark stripe and background dark stripe, the bright stripe between adjacent background dark stripe constitutes the optical virtual electric wetting channel matched with the shape of the droplet to be driven, the droplet to be driven is located in optical virtual electric wetting channel, and the electrode of the both ends of single plane photoelectric wetting chip is connected respectively at the both ends of optical virtual electric wetting channel;Drive dark stripe covers the droplet to be driven, and drive dark stripe moves along optical virtual electric wetting channel.Compared with prior art, the present application generates real-time optical virtual electric wetting channel by acquiring droplet position, and drive dark stripe is matched, to realize the selective control of droplet, avoid the risk of cross contamination between droplets.

Description

Technical Field

[0001] This invention relates to the field of optically controlled electrowetting technology, and in particular to a liquid selective driving method based on an optical virtual electrowetting channel. Background Technology

[0002] Droplet microfluidics has attracted significant research attention due to its promising applications in biochemical reactions, environmental monitoring, and medical detection. Traditional microfluidic devices generate droplets in T- or Y-shaped channels through micropumps or capillary pressure, driving the droplets to flow and mix within the microchannels to achieve functions such as reaction and detection. However, the size, flux, and functionality of the manipulated droplets are limited by the microchannel size, and the non-reconfigurable microchannel chips not only have complex fabrication processes but also lack the flexibility for droplet manipulation. Digital microfluidics, represented by electrowetting on dielectrics (EWOD), are considered an important pathway to realizing lab-on-a-chip technology due to their advantages such as flexibility, programmability, small sample volume, and no cross-contamination. However, EWOD technology relies on pixelated electrodes for droplet manipulation. As the volume and number of manipulated droplets decrease and increase, this technology faces wiring bottlenecks, and the droplet volume, position, and number are limited by fixed electrodes. In recent years, the optically controlled electrowetting (OEW) technique proposed by Chiou et al. has solved this problem well. OEW technology uses projected light patterns to form reconfigurable virtual photoelectrodes on photoconductive films, thereby realizing droplet optical actuation.

[0003] Microchannel-based droplet microfluidic chips control droplet size, throughput, and flexibility, but these are limited by the microchannels themselves. Traditional microchannel chip fabrication processes are complex, and the microchannels are not reconfigurable. EWOD technology based on physical electrodes relies on programmable electrode arrays to manipulate droplets, requiring a large number of control signal sequences to achieve the desired functions.

[0004] Single-plane continuous photoelectrowetting (SCOEW) devices can achieve two-dimensional actuation of droplets on open surfaces and are easy to integrate with other functional units, such as droplet optical detection and sample addition. Chinese patent CN114870915B discloses that when a SCOEW chip drives a droplet to move, a dark stripe perpendicular to the current direction needs to be projected onto the chip surface and moved along the electric field direction to drive the droplet movement.

[0005] However, since the lateral electric field applied to the chip needs to be penetrated by the dark stripes (virtual electrodes), any droplet swept across the area by the dark stripes will be affected or moved, making it impossible to selectively control the droplets. This also increases the risk of droplet cross-contamination. Furthermore, the traditional SCOEW droplet drive system has a low degree of automation and intelligence. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art, which requires the lateral electric field applied to the chip to be penetrated by dark stripes, so that any droplets in the area swept by the dark stripes will be affected or moved, making it impossible to achieve selective control of droplets and increasing the risk of droplet cross-contamination. This invention provides a liquid selective driving method based on an optical virtual electrowetting channel.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] A liquid-selective driving method based on an optical virtual electrowetting channel includes the following steps:

[0009] To obtain the position and size of droplets on a single-plane photoelectrowetting chip;

[0010] The corresponding projection pattern is obtained based on the position, size and preset movement path of the droplet to be driven, and the projection pattern is projected onto the single-plane photoelectric wetting chip;

[0011] The projection pattern includes driving dark stripes, multiple bright stripes, and background dark stripes. The background dark stripes are the same color as the driving dark stripes. The bright stripes between two adjacent background dark stripes form an optical virtual electrowetting channel that matches the shape of the droplet to be driven. The droplet to be driven is located in the optical virtual electrowetting channel. The two ends of the optical virtual electrowetting channel are respectively connected to the electrodes at both ends of the single-plane photoelectric wetting chip.

[0012] The driving dark stripe covers the droplet to be driven, and the driving dark stripe moves along the optical virtual electrowetting channel.

[0013] Preferably, the optical virtual electrowetting channel is updated and reconstructed in real time according to the position and size of the droplet to be driven.

[0014] Preferably, the width of the optical virtual electrowetting channel is 1.3-1.7 times the diameter of the droplet to be driven.

[0015] Preferably, the shape of the optical virtual electrowetting channel includes rectangular and Z-shaped, and the driving dark stripe is perpendicular to the optical virtual electrowetting channel.

[0016] Preferably, the electrodes of the single-plane photoelectric wetting chip are right-angled electrodes.

[0017] Preferably, the RGB value range of the bright stripe is: 245≤R≤255, 245≤G≤255, 245≤B≤255, and the RGB value range of the driving dark stripe and the background dark stripe is: 0≤R≤5, 0≤G≤5, 0≤B≤5.

[0018] Preferably, the color, position, and size of droplets on a single-plane photoelectric wetting chip are obtained through a trained droplet detection model, and the droplets are classified according to the droplet information for classification driving droplets.

[0019] Preferably, the droplet detection model acquires information about the droplet to be driven in real time through a deep learning-based target detection method or target feature extraction method.

[0020] Preferably, there are multiple optical virtual electrowetting channels, and each optical virtual electrowetting channel is parallel to the others.

[0021] Preferably, the width of the driving dark stripe is 40-60% of the diameter of the droplet to be driven.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] (1) In this scheme, the position and size of the droplet on the single-plane photoelectric wetting chip are combined to project the corresponding projection pattern onto the single-plane photoelectric wetting chip. The background dark stripe forms the corresponding optical virtual electrowetting channel for the droplet to be driven. The brightness difference between the driving dark stripe covering the droplet to be driven and the optical virtual electrowetting channel is used to form a virtual electrode that reduces the contact angle of the droplet to be driven. The background dark stripe and the driving dark stripe have the same brightness and will not generate a potential difference for the droplet inside the background dark stripe. Moving the driving dark stripe only moves the droplet in the optical virtual electrowetting channel.

[0024] By real-time detection and tracking of droplets, a corresponding optical virtual electrowetting channel is generated. Combined with the movement of driving dark stripes, selective control of droplet-driven droplets is achieved, enabling droplets to move independently along different paths and avoiding the risk of cross-contamination between droplets.

[0025] (2) In the prior art, the droplet microfluidic chip based on microchannels controls the size, throughput and flexibility of the droplets, which are limited by the microchannels; moreover, the chip fabrication process of microchannels is relatively complex and the microchannels are not reconfigurable. However, in this application, the width of the optical virtual electrowetting channel can be adjusted according to the size of the droplet to be driven, and can be reconfigured according to the position of the droplet to be driven and the preset movement path. The adjustment is flexible and accurate, and can be switched and reconfigured according to the requirements of the droplet to be driven, making it highly applicable.

[0026] (3) The EWOD technology based on physical electrodes relies on a programmable electrode array for droplet manipulation, requiring a large number of control signal sequences to realize the relevant functions. The traditional SCOEW droplet driving system drives the droplet by setting parallel bias electrodes, but the driving direction of such parallel bias electrodes is limited. In this application, a right-angled electrode is set on the single-plane photoelectric wetting chip, which can be used in conjunction with the real-time reconstruction of the direction and position of the optical virtual electrowetting channel to change the driving direction of the droplet, realize the optical control switching of the driving direction, and drive the droplet in various directions. Moreover, the switching of the driving direction of the droplet is convenient and fast.

[0027] (4) Traditional SCOEW droplet driving systems have low levels of automation and intelligence. This application achieves real-time detection and classification of droplets through target detection algorithms, providing real-time parameters for the reconstruction and updating of optical virtual channels, thereby generating optical virtual channels for the corresponding droplets, driving specific types of droplets, and realizing intelligent control of droplets that can be identified. Attached Figure Description

[0028] Figure 1 A schematic diagram of the single-plane photoelectric wetting chip and projection provided by the present invention;

[0029] Figure 2 This is a schematic diagram of the structure of the X-direction optical virtual electrowetting channel provided by the present invention;

[0030] Figure 3 This is a schematic diagram of the Z-shaped optical virtual channel provided by the present invention;

[0031] Figure 4 This is a schematic diagram of the structure of the virtual electrowetting channel in the Y direction under the right-angled electrode provided by the present invention;

[0032] In the figure: 1. Droplet, 2. Projector, 3. Projected pattern, 4. Hydrophobic layer, 5. Insulating layer, 6. Electrode, 7. Amorphous silicon photoconductive thin film, 8. Glass substrate, 9. Driven droplet, 10. Fixed droplet, 11. Driving dark stripe, 12. Background dark stripe, 13. X-direction optical virtual electrowetting channel, 14. Z-shaped optical virtual electrowetting channel, 15. Right-angled electrode, 16. Y-direction optical virtual electrowetting channel. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0034] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0035] 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 further defined and explained in subsequent figures.

[0036] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed during use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0037] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0038] Furthermore, terms such as "horizontal" and "vertical" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0039] Example 1

[0040] This embodiment provides a liquid selective driving method based on an optical virtual electrowetting channel, including the following steps:

[0041] The system acquires the position and size of a droplet on a single-plane photoelectric wetting chip; based on the position, size, and preset movement path of the droplet to be driven, it obtains a corresponding projection pattern and projects this pattern onto the single-plane photoelectric wetting chip; the projection pattern includes driving dark stripes, multiple bright stripes, and background dark stripes. The background dark stripes are the same color as the driving dark stripes. The bright stripes between two adjacent background dark stripes form an optical virtual electrowetting channel that matches the shape of the droplet to be driven. The droplet to be driven is located within the optical virtual electrowetting channel, and the two ends of the optical virtual electrowetting channel are connected to the electrodes at both ends of the single-plane photoelectric wetting chip; the driving dark stripes cover the droplet to be driven and move along the optical virtual electrowetting channel. The structure of the droplet driving device is as follows: Figure 1 As shown.

[0042] By designing the projected pattern on a single-plane photoelectric wetting chip, the potential distribution and current direction on the chip surface can be controlled, thereby forming an arbitrarily reconfigurable droplet-manipulated photovirtual electro-wetting channel. To achieve selective droplet manipulation, i.e., independent manipulation of multiple droplets at the same X-coordinate, the potential distribution on the chip surface is adjusted, such as... Figure 2 As shown. When the two electrodes are connected to the positive and negative terminals respectively, a transverse current is formed in the photoconductive layer of the chip. At this time, dark light and bright light are projected onto the chip surface through the projector 2, forming a background dark stripe in the high-resistivity region and a photo-virtual electrowetting channel in the low-resistivity region. Since both regions are uniform in the X direction, the potential gradient in the X direction decreases uniformly.

[0043] In the vertical direction of the optical virtual electrowetting channel, a driving dark stripe 11 is projected. In the background dark stripe region 12, the driving dark stripe 11 is the same color as the background and will not produce a sudden change in potential gradient in the X direction. Therefore, the contact angle of the droplet 1 in the background dark stripe region 12 will not change, i.e., it will not be driven. However, in the region of the optical virtual electrowetting channel 13 in the X direction, due to the large brightness difference between the driving dark stripe 11 and the background, a large potential gradient change will be formed at the driving dark stripe 11, thereby forming a virtual electrode that reduces the contact angle of the droplet. At this time, moving the driving dark stripe 11 will move the droplet in the region of the optical virtual electrowetting channel 13 in the X direction. Thus, a virtual optical channel for unobstructed movement of the droplet will be formed in the region of the optical virtual electrowetting channel 13 in the X direction, while the background dark stripe region 12 is a fixed area where the droplet cannot move.

[0044] This method combines the position and size of the droplets on the single-plane photoelectric wetting chip to project the corresponding projection pattern onto the single-plane photoelectric wetting chip. The background dark stripes form a corresponding optical virtual electrowetting channel for the droplets to be driven. By utilizing the brightness difference between the driving dark stripe 11 covering the droplets to be driven and the optical virtual electrowetting channel, a virtual electrode is formed to reduce the contact angle of the droplets to be driven. The background dark stripe 12 has the same brightness as the driving dark stripe 11 and will not generate a potential difference for the droplets inside the background dark stripe 12. Moving the driving dark stripe moves the droplets in the optical virtual electrowetting channel.

[0045] By real-time detection and tracking of droplets, a corresponding optical virtual electrowetting channel is generated. Combined with the movement of driving dark stripes, selective control of droplet-driven droplets is achieved, enabling droplets to move independently along different paths and avoiding the risk of cross-contamination between droplets.

[0046] In a preferred embodiment, the optical virtual electrowetting channel is updated and reconstructed in real time based on the position and size of the droplet to be driven. The width of the optical virtual electrowetting channel is 1.3-1.7 times the diameter of the droplet to be driven. The shape of the optical virtual electrowetting channel includes rectangular and Z-shaped, and the driving dark stripes are perpendicular to the optical virtual electrowetting channel.

[0047] The shape of the optical virtual electrowetting channel is not limited to a long rectangle and can be varied according to the real-time size of the droplet to be driven. The channel orientation can also be changed, meaning the bright area can be adjusted as needed. For example... Figure 3 As shown, a Z-shaped optical virtual electrowetting channel 14 is formed on the chip surface, with the remaining area being a dark region. Due to the low resistance of the bright region, a large current flows through it, forming a potential gradient along the channel in the sloping bright region. By projecting a dark stripe perpendicular to the channel, a virtual electrode for driving the droplet can be formed at the stripe. Moving the stripe along the channel can drive the droplet to move within the channel.

[0048] In existing technologies, droplet microfluidic chips based on microchannels control droplet size, throughput, and flexibility, which are limited by the microchannels themselves. Furthermore, the fabrication process for microchannel chips is complex, and the microchannels are not reconfigurable. However, in this application, the width of the photo-virtual electrowetting channel can be adjusted according to the size of the droplet to be driven, and it can be reconfigured according to the position of the droplet and a preset movement path. This allows for flexible and precise adjustment, and the reconfiguration can be switched according to the requirements of the droplet, making it highly adaptable.

[0049] In a preferred embodiment, the electrodes of the single-plane photoelectric wetting chip are right-angled electrodes 15. With a transverse electrode in the X direction, the driving force for the droplet moving along the Y-direction channel is relatively small; therefore, a right-angled electrode is used, such as... Figure 4As shown, potential gradients are generated simultaneously in the X and Y directions (the total potential gradient is along the diagonal of the chip). The current decreases along the X direction due to the high resistance in multiple wide dark regions, therefore there is no significant droplet driving force in this direction. However, in the Y direction, the resistance of the Y-direction optical virtual electrowetting channel 16 region is low, resulting in a larger current and potential gradient. Therefore, after applying dark stripes perpendicular to the Y direction, a large potential gradient abrupt change occurs at the dark stripes within the channel, forming a large virtual electrode at this location, allowing the droplet to move along the Y direction following the dark stripes.

[0050] The EWOD technology based on physical electrodes relies on programmable electrode arrays for droplet manipulation, requiring a large number of control signal sequences to achieve the relevant functions. Traditional SCOEW droplet driving systems drive droplets by setting parallel bias electrodes, but these parallel bias electrodes have limited driving directions for droplets. In this application, a right-angled electrode is set on a single-planar photoelectric wetting chip, which can be used in conjunction with the real-time reconstruction of the direction and position of the optical virtual electrowetting channel to change the driving direction of the droplet, realizing optical control switching of the driving direction. This allows for driving the droplet in various directions, and the switching of the droplet driving direction is convenient and quick.

[0051] Optionally, the RGB value range of the bright stripes is: 245≤R≤255, 245≤G≤255, 245≤B≤255, and the RGB value range of the driving dark stripes and the background dark stripes is: 0≤R≤5, 0≤G≤5, 0≤B≤5. In this embodiment, to maximize the droplet driving force, the RGB value of the bright area is set to (255, 255, 255), while the RGB value of the dark area and the dark stripes is set to (0, 0, 0).

[0052] The color, position, and size of droplets on a single-plane photoelectric wetting chip are obtained through a trained droplet detection model, and the droplets are classified based on the droplet information for classification driving droplets.

[0053] By using machine learning and other methods to learn and detect droplet targets, the position and size of the droplets can be acquired in real time. This information is then input as parameters into a graphical interactive tool module to generate corresponding light / dark areas in real time, forming droplet-driven optical channels. Simultaneously, droplets can be classified, and corresponding optical channels can be generated according to the droplet category as needed, thereby achieving selective manipulation of droplets.

[0054] Traditional SCOEW droplet driving systems have low levels of automation and intelligence. This application achieves real-time droplet detection and classification through a target detection algorithm, providing real-time parameters for the reconstruction and updating of optical virtual channels, thereby generating optical virtual channels for the corresponding droplets, driving specific types of droplets, and realizing intelligent droplet identification and control.

[0055] Specifically, the droplet detection model acquires information about the droplet to be driven in real time using a deep learning-based target detection method or target feature extraction method. Multiple optical virtual electrowetting channels are used, and these channels are parallel to each other. The width of the driving dark stripe is 40-60% of the diameter of the droplet to be driven.

[0056] The following is a specific example of the present invention, such as Figure 1 and Figure 2 As shown, its specific implementation process is as follows:

[0057] 1. An amorphous silicon photoconductive film 7 with a thickness of 500-1000 nm is deposited on a glass substrate 8. Subsequently, a Cr / Au electrode 6 with a thickness of 5 / 100 nm is deposited on the amorphous silicon using physical vapor deposition (PVD). Bias electrodes are formed at both ends using photolithography. Subsequently, a 0.5-2 μm thick SU8 layer and a 0.5-2 μm thick Teflon layer are spin-coated on the chip surface to serve as an insulating layer 5 and a hydrophobic layer 4, respectively.

[0058] 2. Four droplets L1, L2, L3, and L4 are added to the chip surface using a micro-injection pump, with droplet L1 positioned on the same horizontal axis. The droplet coordinates and diameters are (x1, y1, d1), (x2, y2, d2), (x3, y3, d3), and (x4, y4, d4), respectively, where x1 = x2 = x3 = x4.

[0059] 3. Use a computer program to generate virtual channel patterns Channel-1 and Channel-2 in the X direction. The center Y coordinates and widths of Channel-1 and Channel-2 are (y1, 1.5×d1) and (y3, 1.5×d3), respectively, and the rest are dark light.

[0060] 4. Project the generated virtual channel pattern onto the chip surface through projector 2, align the pattern with the chip, so that L1 and L3 are located in the center of Channel-1 and Channel-2, while L2 and L4 fall in the dark light area.

[0061] 5. Keeping the virtual light channel pattern unchanged, another driving dark stripe 11 perpendicular to the X direction is projected so that the dark stripe covers the four droplets 1.

[0062] 6. Turn on the power (signal generator and preamplifier) ​​and apply a DC voltage of 100-200V.

[0063] 7. Move the driving dark stripe so that the two driven droplets 9, L1 and L3, in the channel move with the driving dark stripe 11, while the two fixed droplets 10, L2 and L4, in the dark area are unaffected, thereby achieving selective control of droplets.

[0064] The following is another specific example of the present invention, such as Figure 1 and Figure 4 As shown, its specific implementation process is as follows:

[0065] This embodiment uses a right-angle electrode to manipulate the droplet and utilizes changes in a virtual channel image to switch the droplet driving direction. The specific scheme is as follows:

[0066] 1. A 500-1000 nm amorphous silicon photoconductive film is deposited on a glass substrate. Subsequently, a 5 / 100 nm thick Cr / Au electrode is deposited on the amorphous silicon using physical vapor deposition (PVD). Right-angled electrodes are formed at the upper left and lower right corners of the chip using photolithography. Then, 0.5-2 μm thick SU8 and 0.5-2 μm thick Teflon are spin-coated onto the chip surface as insulating and hydrophobic layers, respectively.

[0067] 2. Two droplets L1 and L2 are added to the chip surface using a micro-injection pump, with the droplets positioned on the same horizontal axis. The droplet coordinates and diameters are (x1, y1, d1) and (x2, y2, d2), respectively, where x1 = x2.

[0068] 3. A virtual channel pattern, Channel-1, is generated using a computer program in the X direction. The center Y coordinate and width of Channel-1 are (y1, 1.5×d1), and the rest of the area is dark.

[0069] 4. Project the generated virtual channel pattern onto the chip surface through a mobile phone screen that is fixed relative to the chip, align the pattern with the chip, and position L1 and L2 at the center of Channel-1 and the center of the dark area, respectively.

[0070] 5. Keeping the virtual optical channel pattern unchanged, another droplet-driven dark stripe perpendicular to the X direction is projected so that the dark stripe covers L1 and L2.

[0071] 6. Turn on the power (signal generator and preamplifier) ​​and apply a DC voltage of 100-200V.

[0072] 7. Move the dark stripe to make droplet L1 in the channel follow the dark stripe and move a distance W1 along the X direction to (x1+W1, y1), while droplet L2 in the dark area is unaffected.

[0073] 8. Switch the optical virtual channel pattern and regenerate an optical virtual channel Channel-2 along the Y direction, where the center X coordinate and width of Channel-2 are (x1, 1.5×d2), used to move L2 in the Y direction and project the pattern onto the chip so that L2 and L1 fall on the center and dark area of ​​Channel-2, respectively.

[0074] 9. Generate a driving dark stripe perpendicular to the Y direction, covering L2, and drive L2 to move a distance W2 along the Y direction to (x1, y2+W2). During the movement, even if the dark stripe passes through y1 (i.e., contacts L1), it will not affect L1. Thus, multi-directional driving of the droplet can be realized.

[0075] The following provides another specific example of the present invention, such as... Figure 1 As shown, its specific implementation process is as follows:

[0076] This embodiment utilizes a target detection algorithm to identify droplets and classifies them according to user requirements. The specific scheme is as follows:

[0077] 1. A 500-1000 nm amorphous silicon photoconductive film is deposited on a glass substrate. Subsequently, a 5 / 100 nm thick Cr / Au electrode is deposited on the amorphous silicon using physical vapor deposition (PVD). Bias electrodes are formed at both ends using photolithography. Then, a 0.5-2 μm thick SU8 layer and a 0.5-2 μm thick Teflon layer are spin-coated onto the chip surface as an insulating layer and a hydrophobic layer, respectively.

[0078] 2. Two droplets, L1 and L2, are added to the chip surface using a micro-injection pump, with the droplets positioned on the same horizontal axis. L1 is red and L2 is green, respectively. The droplet coordinates and diameters are (x1, y1, d1) and (x2, y2, d2), respectively, where x1 = x2.

[0079] 3. Enable the target detection program. Based on the droplet detection model trained in the previous machine learning phase, identify the droplets on the chip and obtain the color information, coordinate position, and diameter of droplets L1 and L2. Ignore positional and dimensional deviations in the detection results.

[0080] 4. Input the target droplet to be driven, such as a red droplet, into the control terminal, and use a computer program to generate a virtual light channel pattern Channel-1 in the X direction. The center Y coordinate and width of Channel-1 are (y1, 1.5×d1), and the rest is dark light.

[0081] 5. Project the generated virtual channel pattern onto the chip surface using a projector, align the pattern with the chip, and ensure that L1 (red) and L2 (green) fall at the center of Channel-1 and the dark area, respectively.

[0082] 6. Keeping the virtual optical channel pattern unchanged, project another droplet-driven dark stripe perpendicular to the X direction, so that the dark stripe covers L1 and L2.

[0083] 7. Turn on the power (signal generator and preamplifier) ​​and apply a DC voltage of 100-200V.

[0084] The movement of the dark stripe causes droplet L1 in the channel to move along with the dark stripe, while droplet L2 in the dark area remains unaffected, thus achieving intelligent control of the droplet.

[0085] The photoconductive layer film can be made of materials with photoconductive effects, such as amorphous silicon, polycrystalline silicon, gallium arsenide, indium phosphide, and vanadium dioxide. The projection pattern generation tool can be Pygame, a Python-based graphical interface development tool, or Tkinter, a graphical interface window generation tool, or Cocos2d-X, a cross-platform graphical interactive application development tool. The projection tool can be a commercial projector, OLED display, LCD display, or a smartphone light source. The direction of the virtual light channel can be customized according to actual needs. In addition to the right-angled electrodes, electrode pairs on both sides of the X and Y directions can be set independently, with independent control of the two pairs of electrodes. The control signal and virtual light channel can be switched according to requirements to achieve efficient two-dimensional droplet actuation. For the real-time droplet information update, deep learning-based target detection methods can be used, such as the YOLO series, SSD algorithm, R-CNN, and Fast R-CNN algorithms; or classic target feature extraction methods can be used, such as the Viola Jones detector and HOG detector.

[0086] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A liquid-selective driving method based on an optical virtual electrowetting channel, characterized in that, Includes the following steps: To obtain the position and size of droplets on a single-plane photoelectrowetting chip; The corresponding projection pattern is obtained based on the position, size and preset movement path of the droplet to be driven, and the projection pattern is projected onto the single-plane photoelectric wetting chip; The projection pattern includes driving dark stripes, multiple bright stripes, and background dark stripes. The background dark stripes are the same color as the driving dark stripes. The bright stripes between two adjacent background dark stripes form an optical virtual electrowetting channel that matches the shape of the droplet to be driven. The droplet to be driven is located in the optical virtual electrowetting channel. The two ends of the optical virtual electrowetting channel are respectively connected to the electrodes at both ends of the single-plane photoelectric wetting chip. The driving dark stripe covers the droplet to be driven, and the driving dark stripe moves along the optical virtual electrowetting channel; The optical virtual electrowetting channel is updated and reconstructed in real time according to the position and size of the droplet to be driven; The shape of the optical virtual electrowetting channel includes rectangular and Z-shaped, and the driving dark stripe is perpendicular to the optical virtual electrowetting channel; The electrodes of the single-plane photoelectric wetting chip are right-angled electrodes.

2. The liquid selective driving method based on an optical virtual electrowetting channel according to claim 1, characterized in that, The width of the optical virtual electrowetting channel is 1.3-1.7 times the diameter of the droplet to be driven.

3. The liquid selective driving method based on an optical virtual electrowetting channel according to claim 1, characterized in that, The RGB value range of the bright stripe is: 245≤R≤255, 245≤G≤255, 245≤B≤255, and the RGB value range of the driving dark stripe and the background dark stripe is: 0≤R≤5, 0≤G≤5, 0≤B≤5.

4. The liquid selective driving method based on an optical virtual electrowetting channel according to claim 1, characterized in that, The color, position, and size of droplets on a single-plane photoelectric wetting chip are obtained through a trained droplet detection model, and the droplets are classified based on the droplet information for classification driving droplets.

5. A liquid selective driving method based on an optical virtual electrowetting channel according to claim 4, characterized in that, The droplet detection model acquires information about the droplet to be driven in real time through a deep learning-based target detection method or target feature extraction method.

6. The liquid selective driving method based on an optical virtual electrowetting channel according to claim 1, characterized in that, The optical virtual electrowetting channels are multiple, and each optical virtual electrowetting channel is parallel to the others.

7. The liquid selective driving method based on an optical virtual electrowetting channel according to claim 1, characterized in that, The width of the driving dark stripe is 40-60% of the diameter of the droplet to be driven.

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