CN117599876A - Liquid selective driving method based on optical virtual electrowetting channel - Google Patents
Liquid selective driving method based on optical virtual electrowetting channel Download PDFInfo
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
- B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
- B01L3/50—Containers for the purpose of retaining a material to be analysed, e.g. test tubes
- B01L3/502—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures
- B01L3/5027—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip
- B01L3/502769—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip characterised by multiphase flow arrangements
- B01L3/502784—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip characterised by multiphase flow arrangements specially adapted for droplet or plug flow, e.g. digital microfluidics
- B01L3/502792—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip characterised by multiphase flow arrangements specially adapted for droplet or plug flow, e.g. digital microfluidics for moving individual droplets on a plate, e.g. by locally altering surface tension
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
- B01L2400/00—Moving or stopping fluids
- B01L2400/04—Moving fluids with specific forces or mechanical means
- B01L2400/0403—Moving fluids with specific forces or mechanical means specific forces
- B01L2400/0415—Moving fluids with specific forces or mechanical means specific forces electrical forces, e.g. electrokinetic
- B01L2400/0427—Electrowetting
Abstract
The invention relates to a liquid selective driving method based on an optical virtual electrowetting channel, which comprises the following steps: acquiring a corresponding projection pattern according to the position and the size of the liquid drop to be driven and a preset moving path, and projecting the projection pattern on a single-plane photoelectric wetting chip; the projection pattern comprises bright stripes, driving dark stripes with the same color and background dark stripes, the bright stripes between adjacent background dark stripes form an optical virtual electrowetting channel matched with the shape of liquid drops to be driven, the liquid drops to be driven are positioned in the optical virtual electrowetting channel, and two ends of the optical virtual electrowetting channel are respectively connected with electrodes at two ends of the single-plane photoelectric electrowetting chip; the driving dark stripes cover the liquid drops to be driven, and the driving dark stripes move along the optical virtual electrowetting channel. Compared with the prior art, the method has the advantages that the positions of the liquid drops are obtained, the real-time optical virtual electrowetting channel is generated to cooperate with the driving dark stripes, the selective control of the liquid drops is realized, and the risk of cross contamination among the liquid drops is avoided.
Description
Technical Field
The invention relates to the technical field of light-operated electrowetting, in particular to a liquid selective driving method based on an optical virtual electrowetting channel.
Background
The droplet microfluidic technology is focused by researchers because of its excellent application prospect in the fields of biochemical reaction, environmental monitoring, medical detection and the like. The traditional microfluidic device generates liquid drops in a T-shaped or Y-shaped channel under the pressure action of a micropump or capillary force, and drives the liquid drops to flow and mix in the micro channel so as to realize the functions of reaction, detection and the like. However, manipulating the size, throughput and function of droplets is limited by the size of the micro-channels, and micro-channel chips that cannot be reconstructed are not only complex to fabricate, but also lack the flexibility of droplet manipulation. Digital microfluidic technologies, represented by electrowetting on dielectric (EWOD), are regarded as important ways to realize lab-on-a-chip by virtue of their flexibility, programmability, small sample usage, and no cross contamination. However, the EWOD technique requires the operation of droplets by means of pixelated electrodes, and as the volume of droplets is reduced and the number of droplets is increased, the technique faces a wiring bottleneck, and the volume, position and number of droplets are limited by fixed electrodes. In recent years, the optical control electrowetting technology (OEW) proposed by Chiou et al well solves this problem, and the OEW technology forms a reconfigurable virtual photoelectrode on a photoconductive film by using a projected light pattern, thereby realizing droplet optical driving.
Droplet microfluidic chips based on microchannels manipulate droplet size, throughput and flexibility are limited by the microchannels; the traditional micro-channel chip manufacturing process is complex, and the micro-channel cannot be reconstructed; manipulation of droplets by physical electrode-based EWOD techniques relies on programmable electrode arrays, requiring a large number of control signal sequences to achieve the relevant function.
Wherein a single planar continuous electro-optical wetting (SCOEW) device can achieve two-dimensional driving of droplets on an open surface while facilitating integration of other functional units such as droplet optical detection, sample addition, etc. Chinese patent CN114870915B discloses that while the SCOEW chip drives the droplet movement, 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.
However, since the lateral electric field applied to the chip needs to be penetrated by the dark stripes (virtual electrodes), the droplets in the area swept by any dark stripes are affected or moved, so that the selective manipulation of the droplets cannot be realized, the risk of cross contamination of the droplets is increased, and the conventional SCOEW droplet driving system has low automation and intelligence.
Disclosure of Invention
The invention aims to overcome the defect that in the prior art, a transverse electric field applied to a chip needs to be penetrated by dark stripes, so that liquid drops in a scanning area of any dark stripes can be influenced or moved, selective control of the liquid drops can not be realized, and meanwhile, the risk of cross contamination of the liquid drops can be increased.
The aim of the invention can be achieved by the following technical scheme:
a liquid selective driving method based on an optical virtual electrowetting channel, comprising the following steps:
acquiring the position and the size of liquid drops on a single-plane photoelectric wetting chip;
acquiring a corresponding projection pattern according to the position and the size of the liquid drop to be driven and a preset moving path, and projecting the projection pattern on a single-plane photoelectric wetting chip;
the projection pattern comprises a driving dark stripe, a plurality of bright stripes and background dark stripes, wherein the color of the background dark stripe is the same as that of the driving dark stripe, the bright stripes between two adjacent background dark stripes form an optical virtual electrowetting channel matched with the shape of liquid drops to be driven, the liquid drops to be driven are positioned in the optical virtual electrowetting channel, and two ends of the optical virtual electrowetting channel are respectively connected with electrodes at two ends of a single-plane photoelectric electrowetting chip;
the driving dark stripes cover the liquid drops to be driven, and the driving dark stripes move along the optical virtual electrowetting channel.
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.
Preferably, the width of the optical virtual electrowetting channel is 1.3-1.7 times of the diameter of the liquid drop to be driven.
Preferably, the shape of the optical virtual electrowetting channel comprises a rectangle and a Z shape, and the driving dark stripe is perpendicular to the optical virtual electrowetting channel.
Preferably, the electrode of the single-plane electro-wetting chip is a right-angle electrode.
Preferably, the bright stripes have RGB value ranges of: r is more than or equal to 245 and less than or equal to 255, G is more than or equal to 245 and less than or equal to 255, B is more than or equal to 245 and less than or equal to 255, and the RGB value ranges of the driving dark stripes and the background dark stripes are as follows: r is more than or equal to 0 and less than or equal to 5, G is more than or equal to 0 and less than or equal to 5, and B is more than or equal to 0 and less than or equal to 5.
Preferably, the color, the position and the size of the liquid drop on the single plane electro-wetting chip are obtained through a trained liquid drop detection model, and the liquid drop is classified according to the information of the liquid drop, so that the liquid drop is classified and driven.
Preferably, the droplet detection model acquires information of the droplet to be driven in real time through a target detection method or a target feature extraction method based on deep learning.
Preferably, the number of the optical virtual electrowetting channels is a plurality, and each optical virtual electrowetting channel is parallel to each other.
Preferably, the width of the driving dark stripe is 40-60% of the diameter of the droplet to be driven.
Compared with the prior art, the invention has the following advantages:
(1) According to the scheme, the positions and the sizes of liquid drops on the single-plane photoelectric wetting chip are combined, the corresponding projection patterns are projected onto the single-plane photoelectric wetting chip, the corresponding optical virtual electrowetting channel is formed for the liquid drops to be driven through the background dark stripes, the virtual electrode for reducing the contact angle of the liquid drops to be driven is formed by utilizing the brightness difference between the driving dark stripes covered on the liquid drops to be driven and the optical virtual electrowetting channel, the brightness of the background dark stripes is consistent with that of the driving dark stripes, potential difference is not generated for the liquid drops in the background dark stripes, the driving dark stripes are moved, and only the liquid drops in the optical virtual electrowetting channel are moved.
By detecting and tracking the liquid drops in real time, a corresponding optical virtual electrowetting channel is generated, and the movement of dark stripes is driven in a matched manner, so that the selective control of liquid drop driving is realized, the liquid drops can independently move along different paths, and the risk of cross contamination among the liquid drops is avoided.
(2) In the prior art, a droplet microfluidic chip based on a micro channel is used for controlling the size of droplets, and the flux and flexibility are limited by the micro channel; and the manufacturing process of the chip of the micro-channel is complex, and the micro-channel cannot be reconstructed. But in this application, the width of the virtual electrowetting channel of light can be adjusted according to the size of waiting to drive the liquid drop, and can be according to waiting to drive the position of liquid drop and predetermine the removal route and reconstruct, adjust nimble accuracy height, and can be according to waiting to drive the requirement switching reconstruction of liquid drop, the suitability is strong.
(3) Manipulation of droplets by physical electrode-based EWOD techniques relies on programmable electrode arrays, requiring a large number of control signal sequences to achieve the relevant function, conventional SCOEW droplet drive systems drive droplets by providing parallel bias electrodes, but such parallel bias electrodes have limited drive direction for droplets. The right-angle type electrode is arranged on the single-plane electro-wetting chip, real-time reconstruction of the direction position of the optical virtual electro-wetting channel can be matched, the driving direction of the liquid drop is changed, optical control switching of the driving direction is realized, driving of all directions can be carried out on the liquid drop, and the driving direction of the liquid drop is switched conveniently and rapidly.
(4) The traditional SCOEW liquid drop driving system is low in automation and intelligent degree, real-time detection and classification of liquid drops are realized through a target detection algorithm, real-time parameters are provided for reconstruction and update of an optical virtual channel, further the optical virtual channel corresponding to the liquid drops is generated, the liquid drops of a specific type are driven, and identifiable and intelligent control of the liquid drops is realized.
Drawings
FIG. 1 is a schematic diagram of a single planar electrowetting chip and projection provided by the present invention;
fig. 2 is a schematic structural diagram of an optical virtual electrowetting channel in the X direction according to the present invention;
FIG. 3 is a schematic diagram of a structure of a Z-shaped optical virtual channel according to the present invention;
fig. 4 is a schematic structural diagram of a Y-direction optical virtual electrowetting channel under a right-angle electrode according to the present invention;
in the figure: 1. drop, 2, projector, 3, projection pattern, 4, hydrophobic layer, 5, insulating layer, 6, electrode, 7, amorphous silicon photoconductive film, 8, glass substrate, 9, driven drop, 10, fixed drop, 11, driven dark stripe, 12, background dark stripe, 13, X-direction optical virtual electrowetting channel, 14, Z-shaped optical virtual electrowetting channel, 15, right angle electrode, 16, Y-direction optical virtual electrowetting channel.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.
In the description of the present invention, it should be noted that, directions or positional relationships indicated by terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., are directions or positional relationships based on those shown in the drawings, or are directions or positional relationships conventionally put in use of the inventive product, are merely for convenience of describing the present invention and simplifying the description, and are not indicative or implying that the apparatus or element to be referred to must have a specific direction, be constructed and operated in a specific direction, and thus should not be construed as limiting the present invention.
It should be noted that the terms "first," "second," and "second" are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implying a number of technical features being indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.
Furthermore, the terms "horizontal," "vertical," and the like do not denote a requirement that the component be absolutely horizontal or overhang, but rather may be slightly inclined. As "horizontal" merely means that its direction is more horizontal than "vertical", and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.
Example 1
The embodiment provides a liquid selective driving method based on an optical virtual electrowetting channel, which comprises the following steps:
acquiring the position and the size of liquid drops on a single-plane photoelectric wetting chip; acquiring a corresponding projection pattern according to the position and the size of the liquid drop to be driven and a preset moving path, and projecting the projection pattern on a single-plane photoelectric wetting chip; the projection pattern comprises a driving dark stripe, a plurality of bright stripes and background dark stripes, the color of the background dark stripe is the same as that of the driving dark stripe, the bright stripes between two adjacent background dark stripes form an optical virtual electrowetting channel matched with the shape of liquid drops to be driven, the liquid drops to be driven are positioned in the optical virtual electrowetting channel, and two ends of the optical virtual electrowetting channel are respectively connected with electrodes at two ends of the single-plane photoelectric electrowetting chip; the driving dark stripes cover the liquid drops to be driven, and the driving dark stripes move along the optical virtual electrowetting channel. The configuration of the droplet drive apparatus is shown in figure 1.
Through the design of projection patterns on a single-plane electro-wetting chip, the regulation and control of the chip surface potential distribution and the current direction are realized, so that an arbitrary reconfigurable liquid drop control optical virtual electro-wetting channel is formed. To achieve selective manipulation of droplets, i.e. independent manipulation of multiple droplets at the same X-coordinate, the chip surface potential distribution is controlled as shown in fig. 2. When the electrodes at the two ends are respectively connected with the positive electrode and the negative electrode, transverse current is formed on the chip photoconductive layer, at the moment, dark light and bright light are projected on the surface of the chip through the projector 2, and a background dark stripe of a high-resistance area and a photo-virtual electrowetting channel of a low-resistance area are formed.
The driving dark stripes 11 are projected in the vertical direction of the optical virtual electrowetting channel, and the driving dark stripes 11 are consistent with the background color in the background dark stripe area 12, and no potential gradient mutation is generated in the X direction, so that the contact angle of the liquid drops 1 in the background dark stripe area 12 is not changed, namely the liquid drops are not driven; in the part of the region of the X-direction optical virtual electrowetting channel 13, because of the large brightness difference between the driving dark stripe 11 and the background, a large potential gradient change is formed at the driving dark stripe 11, so as to form a virtual electrode for reducing the contact angle of liquid drops, and at this time, the liquid drops in the region of the X-direction optical virtual electrowetting channel 13 are moved by moving the driving dark stripe 11. Thus, a virtual light channel for unobstructed movement of the droplet will be formed in the X-direction of the virtual electrowetting channel 13 area, while the background dark stripe 12 area is a fixed area for immobility of the droplet.
The method combines the positions and the sizes of liquid drops on a single-plane photoelectric wetting chip, projects a corresponding projection pattern onto the single-plane photoelectric wetting chip, forms a corresponding optical virtual electrowetting channel for the liquid drops to be driven through a background dark stripe, forms a virtual electrode for reducing the contact angle of the liquid drops to be driven by utilizing the brightness difference between a driving dark stripe 11 and the optical virtual electrowetting channel, and ensures that the brightness of the background dark stripe 12 is consistent with that of the driving dark stripe 11, does not generate potential difference for the liquid drops in the background dark stripe 12, and moves the driving dark stripe to move the liquid drops in the optical virtual electrowetting channel.
By detecting and tracking the liquid drops in real time, a corresponding optical virtual electrowetting channel is generated, and the movement of dark stripes is driven in a matched manner, so that the selective control of liquid drop driving is realized, the liquid drops can independently move along different paths, and the risk of cross contamination among the liquid drops is avoided.
As a preferred embodiment, 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 width of the optical virtual electrowetting channel is 1.3-1.7 times of the diameter of the liquid drop to be driven. The shape of the optical virtual electrowetting channel comprises a rectangle and a Z shape, and the dark stripes are driven to be perpendicular to the optical virtual electrowetting channel.
The shape of the optical virtual electrowetting channel is not limited to a long rectangle, and can be changed according to the real-time size of the droplet to be driven. The channel direction can be changed, i.e. the bright area can be adjusted as required. As shown in fig. 3, a zigzag optical virtual electrowetting channel 14 is formed on the chip surface, and the rest is a dark area. Since the bright areas have low resistance, the current through the area is large, creating a potential gradient along the channel at the sloped bright areas. At this time, a dark stripe perpendicular to the channel is projected, i.e. a virtual electrode for driving the droplet is formed at the stripe, and moving the stripe along the channel can drive the droplet to move in the channel.
In the prior art, a droplet microfluidic chip based on a micro channel is used for controlling the size of droplets, and the flux and flexibility are limited by the micro channel; and the manufacturing process of the chip of the micro-channel is complex, and the micro-channel cannot be reconstructed. But in this application, the width of the virtual electrowetting channel of light can be adjusted according to the size of waiting to drive the liquid drop, and can be according to waiting to drive the position of liquid drop and predetermine the removal route and reconstruct, adjust nimble accuracy height, and can be according to waiting to drive the requirement switching reconstruction of liquid drop, the suitability is strong.
As a preferred embodiment, the electrodes of the uniplanar electrowetting chip are rectangular electrodes 15. In the manner in which the lateral electrodes are disposed in the X-direction, the driving force for moving the droplet along the Y-direction channel is relatively small, and thus a right angle electrode is disposed, as shown in fig. 4, while creating a potential gradient in both the X-direction and the Y-direction (the total potential gradient along the diagonal direction of the chip, the current becomes small at the high resistance of the plurality of wide dark regions in the X-direction, so that no significant droplet driving force exists in that direction, whereas in the Y-direction, the photo-virtual electrowetting channel 16 has a small resistance in the region, the current and the potential gradient are large, so that after a dark stripe perpendicular to the Y-direction is applied, there is a large abrupt change in the potential gradient at the dark stripe in the channel, which position forms a large virtual electrode, and the droplet can move along the Y-direction following the dark stripe.
Manipulation of droplets by physical electrode-based EWOD techniques relies on programmable electrode arrays, requiring a large number of control signal sequences to achieve the relevant function, conventional SCOEW droplet drive systems drive droplets by providing parallel bias electrodes, but such parallel bias electrodes have limited drive direction for droplets. The right-angle type electrode is arranged on the single-plane electro-wetting chip, real-time reconstruction of the direction position of the optical virtual electro-wetting channel can be matched, the driving direction of the liquid drop is changed, optical control switching of the driving direction is realized, driving of all directions can be carried out on the liquid drop, and the driving direction of the liquid drop is switched conveniently and rapidly.
Optionally, the RGB value range of the bright stripe is: r is more than or equal to 245 and less than or equal to 255, G is more than or equal to 245 and less than or equal to 255, B is more than or equal to 245 and less than or equal to 255, and the RGB value ranges of the driving dark stripes and the background dark stripes are as follows: r is more than or equal to 0 and less than or equal to 5, G is more than or equal to 0 and less than or equal to 5, and B is more than or equal to 0 and less than or equal to 5. In this embodiment, for the maximization of the droplet driving force, RGB values of the bright area are set to (255, 255, 255), and RGB values of the dark area and the dark stripe are set to (0, 0).
And acquiring the color, the position and the size of the liquid drops on the single-plane photoelectric wetting chip through the trained liquid drop detection model, classifying the liquid drops according to the information of the liquid drops, and driving the liquid drops in a classified manner.
The method comprises the steps of utilizing a machine learning method and the like to learn and detect a liquid drop target, acquiring the position and the size of the liquid drop in real time, inputting the information as parameters into a graphical interactive tool module, and generating corresponding light/dark areas in real time to form a liquid drop driving light channel. Meanwhile, the liquid drops can be classified, and corresponding optical channels are generated according to the types of the liquid drops as required, so that the selective control of the liquid drops is realized.
The traditional SCOEW liquid drop driving system is low in automation and intelligent degree, real-time detection and classification of liquid drops are realized through a target detection algorithm, real-time parameters are provided for reconstruction and update of an optical virtual channel, further the optical virtual channel corresponding to the liquid drops is generated, the liquid drops of a specific type are driven, and identifiable and intelligent control of the liquid drops is realized.
Specifically, the droplet detection model acquires information of a droplet to be driven in real time by a target detection method or a target feature extraction method based on deep learning. The number of the optical virtual electrowetting channels is multiple, and the optical virtual electrowetting 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.
The following gives a specific example of the present invention, as shown in fig. 1 and 2, and the specific implementation process is:
1. a 500-1000nm amorphous silicon photoconductive film 7 is deposited on a glass substrate 8, followed by a Physical Vapor Deposition (PVD) of a 5/100nm thick Cr/Au electrode 6 on the amorphous silicon. Bias electrodes are formed at both ends through a photolithography process. SU8 with a thickness of 0.5-2 μm and Teflon with a thickness of 0.5-2 μm are then spin-coated on the chip surface as insulating layer 5 and hydrophobic layer 4, respectively.
2. Four liquid drops L are added on the surface of the chip through a micro-injection pump 1 ，L 2 ，L 3 ，L 4 And the droplets 1 are located on the same abscissa. The droplet coordinates and diameter are (x) 1 ，y 1 ，d 1 )，(x 2 ，y 2 ，d 2 )，(x 3 ，y 3 ，d 3 )，(x 4 ，y 4 ，d 4 ) Wherein x is 1 ＝x 2 ＝x 3 ＝x 4 。
3. The X-direction light virtual Channel patterns Channel-1 and Channel-2 are generated using a computer program. Wherein the center Y coordinates and widths of Channel-1 and Channel-2 are (Y) 1 ,1.5×d 1 ),(y 3 ，1.5×d 3 ) The rest is dark light.
4. Projecting the generated virtual channel pattern onto the chip surface by the projector 2, aligning the pattern with the chip, and making L 1 And L 3 At the centers of Channel-1 and Channel-2, and L 2 And L 4 Falls in the dark region.
5. The optical dummy channel pattern is kept unchanged and a driving dark stripe 11 perpendicular to the X-direction is projected so that the dark stripe covers the four drops 1.
6. The power supply (signal generator and pre-amplifier) is turned on and a DC voltage of 100-200V is applied.
7. Moving and driving dark stripes to make L in channel 1 And L 3 The two driven droplets 9 move following the driving dark stripe 11, while L in the dark area 2 And L 4 The two stationary droplets 10 are unaffected, thereby achieving droplet selective manipulation.
A further embodiment of the present invention is shown in fig. 1 and 4, and is specifically implemented as follows:
the embodiment uses the right-angle electrode to operate the liquid drop, and uses the virtual channel image change to realize the liquid drop driving direction switching, and the specific scheme is as follows:
1. a500-1000 nm amorphous silicon photoconductive film is deposited on a glass substrate, followed by Physical Vapor Deposition (PVD) of Cr/Au electrodes having a thickness of 5/100nm on the amorphous silicon. Right angle shaped electrodes are formed at the upper left and lower right corners of the chip by a photolithography process. Then spin-coating SU8 with the thickness of 0.5-2 mu m and Teflon with the thickness of 0.5-2 mu m are respectively used as an insulating layer and a hydrophobic layer on the surface of the chip.
2. Two liquid drops L are added on the surface of the chip through a micro-injection pump 1 ，L 2 And the droplets are located on the same abscissa. The droplet coordinates and diameter are (x) 1 ，y 1 ，d 1 )，(x 2 ，y 2 ，d 2 ) Wherein x is 1 ＝x 2 。
3. An X-ray virtual Channel pattern Channel-1 is generated using a computer program. Wherein the center Y coordinate and width of Channel-1 are (Y) 1 ,1.5×d 1 ) The rest is dark light.
4. Projecting the generated virtual channel pattern to the surface of the chip through a mobile phone screen relatively fixed with the chip, aligning the pattern and the chip, and enabling L to be the same as that of the chip 1 And L 2 Respectively at the center of Channel-1 and the center of the dark region.
5. Keeping the pattern of the optical virtual channel unchanged, projecting a droplet perpendicular to the X direction to drive dark stripes to cover L 1 And L 2 。
6. The power supply (signal generator and pre-amplifier) is turned on and a DC voltage of 100-200V is applied.
7. Moving to drive dark stripes to make liquid drop L in channel 1 Moves along the X direction by a distance W1 following the dark stripe to reach (X 1 +W 1 ，y 1 ) While droplets L in the dark region 2 Is not affected.
8. Switching the optical virtual Channel pattern to regenerate an optical virtual Channel-2 along the Y-direction, wherein the center X-coordinate and width of Channel-2 are (X 1 ,1.5×d 2 ) For moving L in Y direction 2 And projecting the pattern onto the chip to make L 2 And L 1 Respectively in the Channel-2 center and in the dark area.
9. Generating driving dark stripes perpendicular to the Y direction to cover L 2 And drive L 2 Move along Y direction by a distance W 2 Reach (x) 1 ，y 2 +W 2 ) During movement, even if dark stripes pass y 1 (i.e. contact with L 1 ) Nor is it directed to L 1 An influence is generated. Thus, multidirectional driving of the droplets can be achieved.
Another embodiment of the present invention is shown in fig. 1, and the implementation process is as follows:
the embodiment utilizes a target detection algorithm to identify liquid drops and classifies and drives the liquid drops according to user requirements, and the specific scheme is as follows:
1. a500-1000 nm amorphous silicon photoconductive film is deposited on a glass substrate, followed by Physical Vapor Deposition (PVD) of Cr/Au electrodes having a thickness of 5/100nm on the amorphous silicon. Bias electrodes are formed at both ends through a photolithography process. Then spin-coating SU8 with the thickness of 0.5-2 mu m and Teflon with the thickness of 0.5-2 mu m are respectively used as an insulating layer and a hydrophobic layer on the surface of the chip.
2. Two liquid drops L are added on the surface of the chip through a micro-injection pump 1 ，L 2 And positioning the droplets on the same abscissa, where L 1 And L 2 Red and green, respectively. The droplet coordinates and diameter are (x) 1 ，y 1 ，d 1 )，(x 2 ，y 2 ，d 2 ) Wherein x is 1 ＝x 2 。
3. Starting a target detection program, and identifying the liquid drops on the chip according to a liquid drop detection model obtained by earlier machine learning training to obtain liquid drops L 1 ，L 2 Color information, coordinate position and diameter. The position and size deviations in the detection result are ignored.
4. The target liquid drop to be driven, such as red liquid drop, is input at the control end, and the X-direction light virtual Channel pattern Channel-1 is generated by using a computer program. Wherein the center Y coordinate and width of Channel-1 are (Y) 1 ,1.5×d 1 ) The rest is dark light.
5. Projecting the generated virtual channel pattern to the chip surface by a projector, aligning the pattern with the chip to enable L 1 (Red) and L 2 The (green) color falls in the center of Channel-1 and the dark region, respectively.
6. Keeping the pattern of the optical virtual channel unchanged, projecting a droplet perpendicular to the X direction to drive dark stripes to cover L 1 And L 2 。
7. The power supply (signal generator and pre-amplifier) is turned on and a DC voltage of 100-200V is applied.
Moving to drive dark stripes to make liquid drop L in channel 1 Moves following the dark stripe, while the droplet L in the dark area 2 Is not affected, thereby realizing the identifiable and intelligent control of the liquid drops.
The photoconductive layer film can be amorphous silicon, polycrystalline silicon, gallium arsenide, indium phosphide, vanadium dioxide and other materials with photoconductive effect; the projection pattern generating tool can be a Python-based graphical interface development tool Pygame, a Tlater-like graphical interface window generating tool, or a cross-platform-realizable graphical interactive application development tool Cocos2d-X, and the like; the projection tool can be a commercial projector, an OLED display, an LCD display, a smart phone and other light sources; the direction of the optical virtual channel can be set in a personalized way according to actual requirements; besides the rectangular electrode, electrode pairs on two sides of the X direction and the Y direction can be independently arranged, the two pairs of electrodes are independently controlled, and a control signal and a virtual light channel are switched according to requirements, so that two-dimensional efficient driving of liquid drops is realized; in the liquid drop real-time information updating part, a target detection method based on deep learning, such as a YOLO series, an SSD algorithm, an R-CNN algorithm, a Fast R-CNN algorithm and the like, can be adopted; classical target feature extraction methods such as Viola Jones detector, HOG detector, etc. may also be employed.
The foregoing describes in detail preferred embodiments of the present invention. It should be understood that numerous modifications and variations can be made in accordance with the concepts of the invention by one of ordinary skill in the art without undue burden. Therefore, all technical solutions which can be obtained by logic analysis, reasoning or limited experiments based on the prior art by the person skilled in the art according to the inventive concept shall be within the scope of protection defined by the claims.
Claims (10)
1. The liquid selective driving method based on the optical virtual electrowetting channel is characterized by comprising the following steps of:
acquiring the position and the size of liquid drops on a single-plane photoelectric wetting chip;
acquiring a corresponding projection pattern according to the position and the size of the liquid drop to be driven and a preset moving path, and projecting the projection pattern on a single-plane photoelectric wetting chip;
the projection pattern comprises a driving dark stripe, a plurality of bright stripes and background dark stripes, wherein the color of the background dark stripe is the same as that of the driving dark stripe, the bright stripes between two adjacent background dark stripes form an optical virtual electrowetting channel matched with the shape of liquid drops to be driven, the liquid drops to be driven are positioned in the optical virtual electrowetting channel, and two ends of the optical virtual electrowetting channel are respectively connected with electrodes at two ends of a single-plane photoelectric electrowetting chip;
the driving dark stripes cover the liquid drops to be driven, and the driving dark stripes move along the optical virtual electrowetting channel.
2. The method of claim 1, wherein the optical virtual electrowetting channel is updated and reconfigured in real time according to the position and size of the droplet to be driven.
3. The method for selectively driving a liquid based on an optical virtual electrowetting channel according to claim 2, wherein the width of the optical virtual electrowetting channel is 1.3-1.7 times the diameter of the liquid drop to be driven.
4. The method of claim 2, wherein the optical virtual electrowetting channel comprises a rectangular shape and a zigzag shape, and the driving dark stripe is perpendicular to the optical virtual electrowetting channel.
5. The method for selectively driving a liquid based on an optical virtual electrowetting channel according to claim 1, wherein the electrode of the single-plane electrowetting chip is a right-angle electrode.
6. The method for selectively driving a liquid based on an optical virtual electrowetting channel according to claim 1, wherein the range of RGB values of the bright stripes is: r is more than or equal to 245 and less than or equal to 255, G is more than or equal to 245 and less than or equal to 255, B is more than or equal to 245 and less than or equal to 255, and the RGB value ranges of the driving dark stripes and the background dark stripes are as follows: r is more than or equal to 0 and less than or equal to 5, G is more than or equal to 0 and less than or equal to 5, and B is more than or equal to 0 and less than or equal to 5.
7. The method for selectively driving liquid based on an optical virtual electrowetting channel according to claim 1, wherein the color, position and size of the liquid drop on the single plane electrowetting chip are obtained by a trained liquid drop detection model, and the liquid drop is classified according to the information of the liquid drop, so as to be used for classifying and driving the liquid drop.
8. The method for selectively driving liquid based on the optical virtual electrowetting channel according to claim 7, wherein the liquid drop detection model acquires information of liquid drops to be driven in real time through a target detection method or a target feature extraction method based on deep learning.
9. The method according to claim 1, wherein the number of the optical virtual electrowetting channels is plural, and each optical virtual electrowetting channel is parallel to each other.
10. The method according to claim 1, wherein the width of the driving dark stripe is 40-60% of the diameter of the droplet to be driven.
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