Droplet moving device based on optical sensor vertical distance detection

Abstract

The application relates to a liquid drop moving device based on optical sensor vertical distance detection and relates to the microfluidic field. The liquid drop moving device based on optical sensor vertical distance detection comprises an optical sensor, a driving electrode set and a control assembly; the optical sensor is installed on a mechanical arm; the control assembly is used for controlling the movement of the optical sensor on a plane parallel to a contact plane by controlling the movement of the mechanical arm, wherein the contact plane is a surface contacted by the liquid drop and the driving electrode set; the position of the optical sensor is adjusted to a position closest to the liquid drop, the adjusted position of the optical sensor is obtained; in the movement process of the liquid drop, the distance of the movement of the optical sensor is determined through the adjusted position; the position information of the liquid drop in the driving electrode set is obtained according to the distance of the movement of the optical sensor; and each driving electrode in the driving electrode set is controlled to be opened or closed according to the position information, so that the liquid drop moves on the surface of the driving electrode set. The application is used to solve the problem of high positioning cost of microfluidic liquid drops.

Description

Technical Field

[0001] This application relates to the field of microfluidics, and more particularly to a droplet movement device based on vertical distance detection using an optical sensor. Background Technology

[0002] Digital microfluidics is a technology that precisely manipulates the generation, movement, and fusion of droplets based on the dielectric wetting effect. It offers advantages such as high throughput, automation, low reagent requirements, and rapid reactions, and has been widely applied in DNA preparation, molecular diagnostics, immunoassay, drug analysis, and chemical experiments. Digital microfluidics can now manipulate droplets as small as nanoliters. Simply put, the dielectric wetting effect changes the wettability of a droplet by applying a voltage. Without voltage, the droplet lies on a superhydrophobic material surface with a very small contact angle, exhibiting a near-spherical shape. Applying voltage increases the contact angle, creating a pressure difference within the droplet, which causes it to collapse, thus moving the droplet.

[0003] Currently, most research focuses on how to prepare better substrates, stronger driving capabilities, and achieve faster droplet movement, with relatively little research on droplet positioning. However, the biggest advantage of digital microfluidics over traditional microfluidics lies in automation, and the most important aspect of achieving automation is how to accurately and quickly locate the current position of the droplet.

[0004] Currently, commonly used positioning systems include the following: One method uses an imaging system to capture droplet images in real time to determine the droplet's position, but high-precision imaging systems are expensive. Another method utilizes the change in capacitance of the driving electrode caused by the droplet; circuitry integrated into the substrate sends this capacitance change back to the processor, which then determines the droplet's position. However, this method is highly dependent on the droplet's characteristics and is difficult to adapt to a wide variety of biochemical reagents. The polarity may also change after the droplet mixes and reacts, increasing the difficulty of positioning. Furthermore, with the continuous advancement of digital microfluidics technology, the size of droplets is decreasing, meaning the capacitance change caused by the droplet is also decreasing. This requires more sensitive capacitance detection chips, leading to higher costs and larger errors. Summary of the Invention

[0005] This application provides a droplet movement device based on vertical distance detection using an optical sensor to solve the problem of high cost in microfluidic droplet positioning.

[0006] In a first aspect, embodiments of this application provide a droplet moving device based on vertical distance detection using an optical sensor, comprising an optical sensor, a drive electrode assembly, and a control component; the optical sensor is mounted on a robotic arm.

[0007] The control component is used to control the movement of the robotic arm to move the photosensor on a plane parallel to the contact plane, wherein the contact plane is the surface in contact between the droplet and the drive electrode assembly; adjust the position of the photosensor to be closest to the droplet, thereby obtaining the adjusted position of the photosensor; determine the distance the photosensor has moved during the movement of the droplet based on the adjusted position; obtain the position information of the droplet in the drive electrode assembly based on the distance the photosensor has moved; and control each drive electrode in the drive electrode assembly to open or close based on the position information, so that the droplet moves on the surface of the drive electrode assembly.

[0008] Optionally, the driving electrode set includes a first driving electrode and a second driving electrode; the first driving electrode and the second driving electrode share a common driving electrode, which is used as a collecting electrode; the droplet includes a first droplet and a second droplet;

[0009] The control component is specifically configured to control the movement of the robotic arm to move the photosensor on a plane parallel to the first contact plane, wherein the first contact plane is the surface in contact between the first droplet and the first driving electrode; adjust the position of the photosensor to be closest to the first droplet, thereby obtaining an adjusted first position of the photosensor; determine a first distance the photosensor moves based on the adjusted first position during the movement of the first droplet; obtain first position information of the first droplet in the first driving electrode based on the first distance the photosensor moves; and control each driving electrode in the first driving electrode to open or close based on the first position information, so that the first droplet moves on the surface of the first driving electrode until the first droplet moves to the surface of the collecting electrode.

[0010] The control component is specifically used to control the movement of the robotic arm to move the photosensor on a plane parallel to the second contact plane, wherein the second contact plane is the surface in contact with the second droplet and the second driving electrode; adjust the position of the photosensor to the position closest to the second droplet to obtain the adjusted second position of the photosensor; determine the second distance the photosensor moves by the adjusted second position during the movement of the second droplet; obtain the second position information of the second droplet in the second driving electrode based on the second distance the photosensor moves; and control each driving electrode in the second driving electrode to open or close according to the second position information, so that the second droplet moves on the surface of the second driving electrode until the second droplet moves to the surface of the collecting electrode.

[0011] The control component is specifically used to mix the first droplet and the second droplet on the surface of the collecting electrode to obtain a mixed droplet.

[0012] Optionally, the control component is specifically configured to: when the first droplet is in its initial position, acquire a third distance between the current position of the first droplet and the current position of the optical sensor; control the optical sensor to move at a preset interval on a plane parallel to the first contact plane, centered on the current position of the optical sensor; and reacquire the third distance between the positions of the first droplet and the optical sensor after the movement; take the position of the optical sensor corresponding to the minimum third distance as the center, reduce the preset interval according to a preset rule, and then return to execute the step of controlling the optical sensor to move at a preset interval on a plane parallel to the first contact plane, until the number of executions equals the preset number of times, and then take the position of the optical sensor as the adjusted first position of the optical sensor.

[0013] Optionally, the control component is specifically used to, during the movement of the first droplet, use the distance between two adjacent adjusted first positions as the electrode spacing between two adjacent driving electrodes in the first driving electrode path.

[0014] Optionally, the control component is specifically used to calculate the quotient obtained by dividing the first distance moved by the optical sensor by the electrode spacing, and to obtain the first position information of the first droplet in the first driving electrode based on the quotient.

[0015] Optionally, the control component is further configured to: use the distance between the adjusted first position of the light sensor and the first droplet as a fourth distance; after obtaining the mixed droplet, adjust the position of the light sensor to the position closest to the mixed droplet to obtain the adjusted third position of the light sensor; use the distance between the adjusted third position of the light sensor and the mixed droplet as a fifth distance; obtain the first height of the first droplet; obtain the second height of the mixed droplet; subtract the first height from the second height as the increased height after droplet mixing; adjust the height of the light sensor according to the fourth distance, the fifth distance, and the increased height; after adjusting the height of the light sensor, obtain the adjusted fourth distance and the adjusted fifth distance; and determine whether the first droplet and the second droplet have been successfully mixed according to the adjusted fourth distance, the adjusted fifth distance, and the increased height.

[0016] Optionally, the control component is specifically configured to: when the increased height is greater than or equal to a preset value, set the first ratio value obtained by dividing the fourth distance by the fifth distance as a first preset ratio value; calculate the fourth distance based on the increased height and the first preset ratio value; use the sum of the fourth distance and the first height as the adjusted height of the light sensor; adjust the height of the light sensor based on the adjusted height of the light sensor; calculate the adjusted fourth distance divided by the adjusted fifth distance to obtain a second ratio value; calculate the second ratio value divided by the first preset ratio value to obtain a third ratio value; determine whether the third ratio value is within a first preset range; if the third ratio value is within the first preset range, determine that the first droplet and the second droplet have successfully mixed; if the third ratio value is not within the first preset range, determine that the first droplet and the second droplet have not successfully mixed.

[0017] Optionally, the control component is specifically configured to: when the increased height is less than a preset value, set a fourth ratio value obtained by dividing the increased height by the fourth distance as a second preset ratio value; calculate the fourth distance based on the increased height and the second preset ratio value; use the sum of the fourth distance and the first height as the adjusted height of the light sensor; adjust the height of the light sensor based on the adjusted height of the light sensor; calculate the increased height divided by the adjusted fourth distance to obtain a fifth ratio value; determine whether the fifth ratio value is within a second preset range; if the fifth ratio value is within the second preset range, determine that the first droplet and the second droplet have successfully mixed; if the fifth ratio value is not within the second preset range, determine that the first droplet and the second droplet have not successfully mixed.

[0018] Optionally, the optical sensor is configured to, within a preset time period, if it receives at least two successively decaying reflection intensity values, retain only the largest reflection intensity value; and obtain a third distance between the first droplet and the current position of the optical sensor based on the largest reflection intensity value.

[0019] Optionally, the control component is further configured to, after determining that the first droplet and the second droplet have successfully mixed, control each driving electrode in the first driving electrode to open or close, so that the mixed droplet moves on the surface of the first driving electrode to the mixed solution detection position and moves to the waste liquid tank after a preset time period; or, control each driving electrode in the second driving electrode to open or close, so that the mixed droplet moves on the surface of the second driving electrode to the mixed solution detection position and moves to the waste liquid tank after a preset time period.

[0020] Compared with the prior art, the technical solution provided in this application has the following advantages: In this application, the control component controls the optical sensor to move on a plane parallel to the contact plane, wherein the contact plane is the surface where the droplet and the driving electrode assembly contact. The position of the optical sensor is adjusted to be closest to the droplet. During the movement of the droplet, the position information of the droplet in the driving electrode assembly is obtained by measuring the distance moved by the optical sensor, thereby locating the droplet. This allows for intuitive, fast, accurate, and low-cost droplet positioning, without considering the influence of droplet polarity, size, or other factors, thus having a wider range of applications. Moreover, the driving electrode assembly includes various driving electrodes, which are microfluidic chips. The area of ​​microfluidic chips is usually very small, which means that the optical sensor can obtain results faster. The speed of light propagation is extremely fast, and the data processing speed is also very fast. The integrated optical sensor detection can achieve very fast results. In addition, most microfluidic droplets are visible to the naked eye, and the diameter of the LED beam is much smaller than this scale, and the distance is very short, greatly reducing the beam divergence, which ensures the accuracy of detection. This solves the problem of high cost in microfluidic droplet positioning. Attached Figure Description

[0021] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of a droplet moving device based on vertical distance detection using an optical sensor, as described in an embodiment of this application.

[0024] Figure 2 This is a schematic diagram of a droplet moving device based on vertical distance detection using an optical sensor, according to a specific embodiment of this application.

[0025] Figure 3 This is a schematic diagram of the driving electrode driving the droplet movement in a specific embodiment of this application;

[0026] Figure 4 This is a schematic diagram of optical sensor calibration in a specific embodiment of this application;

[0027] Figure 5 This is a schematic diagram of electrode spacing measurement in a specific embodiment of this application;

[0028] Figure 6This is a schematic diagram illustrating the determination of whether the first droplet and the second droplet have successfully mixed in a specific embodiment of this application;

[0029] Figure 7 This is a schematic diagram of a droplet moving device based on vertical distance detection using an optical sensor, according to a specific embodiment of this application. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0031] In this embodiment of the application, a droplet movement device based on vertical distance detection using an optical sensor is provided, such as... Figure 1 As shown, a droplet moving device based on vertical distance detection using an optical sensor includes an optical sensor 100, a drive electrode assembly 200, and a control component 300; the optical sensor 100 is mounted on a robotic arm.

[0032] The control component 300 is used to control the movement of the robotic arm to move the light sensor 100 on a plane parallel to the contact plane, wherein the contact plane is the surface where the droplet and the drive electrode assembly 200 contact; adjust the position of the light sensor 100 to the position closest to the droplet to obtain the adjusted position of the light sensor 100; determine the distance moved by the light sensor 100 during the movement of the droplet based on the adjusted position; obtain the position information of the droplet in the drive electrode assembly 200 based on the distance moved by the light sensor 100; and control each drive electrode in the drive electrode assembly 200 to open or close based on the position information to make the droplet move on the surface of the drive electrode assembly 200.

[0033] Among them, the optical sensor is a distance detection optical sensor. Distance detection optical sensors are already mature in the market, offering high sensitivity, fast response, macro detection, high accuracy, and low price. There are two detection principles: one is based on light propagation time. A light source emits light, and upon contact with an object, a portion of the light is reflected back. The distance between the object and the optical sensor can be calculated by multiplying the time difference between emission and reception by the speed of light and dividing by 2. The other principle is based on light attenuation. A light source emits light, and upon contact with an object, a portion of the light is reflected back. The closer the object, the stronger the reflected light, and the less attenuation; conversely, the farther away the object, the greater the attenuation. Based on the relationship between distance and attenuation, the distance between the object and the optical sensor can be calculated.

[0034] In terms of precision, droplet diameters and movement steps in microfluidic systems are typically on the millimeter level. Commercially available high-precision micro-sensors can support this level of precision at their minimum detection distance (vertical detection, sensor positioned above the droplet; closer proximity increases accuracy), achieving a minimum detection precision of 10 micrometers (far smaller than the droplet size). Commercially available robotic arms can move in steps as small as ten micrometers (far smaller than the distance a droplet moves in a single movement), with precision below one micrometer. The LED beam diameter is much smaller than this scale, and the distance is very short, significantly reducing beam divergence, which ensures high detection accuracy.

[0035] Based on position information, the control component controls the opening or closing of each driving electrode in the driving electrode set, causing the droplet to move on the surface of the driving electrode set. This is a commonly used microfluidic control method for droplet movement. For example, the control component controls the next driving electrode corresponding to the position information to open, and controls the other driving electrodes in the driving electrode set to close, so that the droplet moves to the surface of the next driving electrode corresponding to the position information.

[0036] In this application, the control component controls the optical sensor to move on a plane parallel to the contact plane, where the contact plane is the surface where the droplet and the drive electrode assembly meet. The position of the optical sensor is adjusted to be closest to the droplet. During the droplet's movement, the distance the optical sensor moves is used to obtain the droplet's position information within the drive electrode assembly, thus enabling droplet localization. This method provides intuitive, fast, accurate, and low-cost droplet localization, without considering the influence of droplet polarity, size, or other factors, thus broadening its applicability. Furthermore, the drive electrode assembly includes individual drive electrodes, which are essentially microfluidic chips. Microfluidic chips typically have a very small area, meaning the optical sensor can obtain results much faster. Light propagation speed is extremely fast, and data processing speed is also very fast; integrating these optical sensors allows for very rapid detection. Additionally, most microfluidic droplets are visible to the naked eye, while the LED beam diameter is much smaller and the distance is very short, greatly reducing beam divergence and ensuring detection accuracy. This solves the problem of high cost in microfluidic droplet localization.

[0037] In one specific embodiment, such as Figure 2 As shown, the driving electrode set 200 includes a first driving electrode 210 and a second driving electrode 220; the first driving electrode 210 and the second driving electrode 220 have a common driving electrode 44, which is used as a collecting electrode 44; the droplet includes a first droplet and a second droplet.

[0038] The control component 300 is specifically used to control the movement of the robotic arm to move the light sensor 100 on a plane parallel to the first contact plane, wherein the first contact plane is the surface in contact between the first droplet and the first driving electrode 210; adjust the position of the light sensor 100 to the position closest to the first droplet to obtain the adjusted first position of the light sensor 100; determine the first distance the light sensor 100 moves by means of the adjusted first position during the movement of the first droplet; obtain the first position information of the first droplet in the first driving electrode 210 based on the first distance the light sensor 100 moves; and control each driving electrode in the first driving electrode 210 to open or close based on the first position information, so that the first droplet moves on the surface of the first driving electrode 210 until the first droplet moves to the surface of the collecting electrode 44.

[0039] The control component 300 is specifically used to control the movement of the robotic arm to move the light sensor 100 on a plane parallel to the second contact plane, wherein the second contact plane is the surface in contact with the second droplet and the second driving electrode 220; adjust the position of the light sensor 100 to the position closest to the second droplet to obtain the adjusted second position of the light sensor 100; determine the second distance the light sensor 100 moves by means of the adjusted second position during the movement of the second droplet; obtain the second position information of the second droplet in the second driving electrode 220 based on the second distance the light sensor 100 moves; and control each driving electrode in the second driving electrode 220 to open or close based on the second position information, so that the second droplet moves on the surface of the second driving electrode 220 until the second droplet moves to the surface of the collecting electrode 44.

[0040] The control component 300 is specifically used to mix the first droplet and the second droplet on the surface of the collecting electrode 44 to obtain a mixed droplet.

[0041] Figure 2 In the example, the first driving electrode 210 and the second driving electrode 220 are perpendicular, but this is only for illustration. As needed, the first driving electrode 210 and the second driving electrode 220 do not necessarily have to be perpendicular. They can intersect but not be perpendicular, as long as the first driving electrode 210 and the second driving electrode 220 have a common driving electrode 44.

[0042] Figure 2 In this configuration, the first droplet is initially positioned on the surface of the driving electrode 11, and its movement direction is from the driving electrode 11 to the driving electrode 44. The second droplet is initially positioned on the surface of the driving electrode 21, and its movement direction is from the driving electrode 21 to the driving electrode 44. Figure 2The electrode spacing between each driving electrode is also shown.

[0043] Figure 2 In the diagram, the dashed circle represents the light sensor 100. Initially, the first droplet is positioned on the surface of the driving electrode 11, and the light sensor 100 is located directly above the first droplet. During the movement of the first droplet, the second droplet remains stationary, and the light sensor 100 follows the first droplet until it reaches the surface of the collecting electrode 44. Then, the second droplet is initially positioned on the surface of the driving electrode 21, and the light sensor 100 moves directly above it. During the movement of the second droplet, the first droplet remains stationary, and the light sensor 100 follows the second droplet until it reaches the surface of the collecting electrode 44. Finally, the first and second droplets mix on the surface of the collecting electrode 44 to form a mixed droplet.

[0044] In one specific embodiment, such as Figure 3 The diagram illustrates the movement of a droplet driven by a driving electrode. The first droplet is on the surface of driving electrode 12. At this time, driving electrodes 11, 12, 13, and 14 are all in the off state. Then, driving electrode 13 is turned on. The control component 300 confirms that the first droplet's first position information in the first driving electrode 210 is indeed on the surface of driving electrode 13, indicating that the first droplet has successfully moved to the surface of driving electrode 13. At this point, driving electrode 13 is turned off. Next, driving electrode 14 is turned on, and so on, until the first droplet is located on the surface of driving electrode 44. Similarly, positioning feedback ensures that the second droplet moves to the surface of driving electrode 44.

[0045] In one specific embodiment, the control component is specifically configured to: acquire a third distance between the first droplet and the current position of the light sensor when the first droplet is in its initial position; control the light sensor to move at a preset interval on a plane parallel to the first contact plane, centered on the current position of the light sensor; and reacquire the third distance between the positions of the first droplet and the light sensor after the movement; take the position of the light sensor corresponding to the minimum third distance as the center, reduce the preset interval according to a preset rule, and then return to execute the step of controlling the light sensor to move at a preset interval on a plane parallel to the first contact plane, until the number of executions equals the preset number of times, and then take the position of the light sensor as the adjusted first position of the light sensor.

[0046] like Figure 4The diagram shows a schematic of the optical sensor calibration. The dashed rectangle represents the movement range for optical sensor calibration. Adjusting the position of the optical sensor on a plane parallel to the first contact plane is to ensure that the LED beam hits the droplet. To facilitate calibration and to ensure a stronger signal is captured by the attenuating sensor, the calibration point is set at the position closest to the optical sensor from the droplet.

[0047] For example: Ignoring the droplet generation process, assume the initial position of the first generated droplet is on the surface of the driving electrode 11. First, adjust the position of the photosensor to be near the first droplet. Using the current position of the photosensor as the center, the robotic arm moves the photosensor to 3*3 points on the plane. The distance between each point is relatively large to ensure coverage of the entire droplet, and each point is tested. The point with the smallest measured distance is the closest point to the photosensor. Continuing with this point as the center, the spacing is halved to define 8 surrounding points. This 3*3 matrix is ​​tested again, and the point with the smallest distance is taken as the new center. The spacing is then halved again, and a new center is obtained in the same way. Through this gradual approximation method, after 4-5 approximations, the photosensor position is calibrated. Figure 4 The solid line with arrows is shown between the optical sensor and the droplet.

[0048] Setting the calibration point at the position where the droplet is closest to the photosensor ensures that the initial adjusted position of the photosensor can be accurately determined each time, thereby accurately measuring the distance between the initial adjusted position of the photosensor and the first droplet. Figure 4 The length of the solid line with arrows between the optical sensor and the droplet facilitates later comparison with the mixed droplet. Furthermore, the calibration point is set at the position where the droplet is closest to the optical sensor, and the electrode spacing between two adjacent driving electrodes in the first driving electrode path can be measured based on the distance between two consecutive adjusted first positions.

[0049] In one specific embodiment, the control component is specifically used to, during the movement of the first droplet, use the distance between two adjacent adjusted first positions as the electrode spacing between two adjacent driving electrodes in the first driving electrode path.

[0050] like Figure 5 The diagram shown illustrates the electrode spacing measurement process. First, a superhydrophobic layer is coated on the driving electrode. Once a droplet is applied and stabilizes, it will be positioned in the center of the driving electrode (or, in other words, the driving electrode and the droplet will be coaxially aligned). This provides a foundation for the subsequent calculation of the electrode spacing D. The calculation process for the electrode spacing D is as follows: Figure 5As shown, the position of the solid line with arrows between the photosensor and the droplet is calculated through calibration (this position is actually the shortest distance between the sensor's light source and the droplet). Then, the droplet is moved to the next position, and the position of the photosensor is adjusted appropriately and a second calibration is performed to obtain the position of the dashed line with arrows between the photosensor and the droplet. In the above process, the final distance the photosensor moves is the electrode spacing D.

[0051] In one specific embodiment, the control component is specifically used to calculate the quotient obtained by dividing the first distance moved by the optical sensor by the electrode spacing, and based on the quotient, obtain the first position information of the first droplet in the first driving electrode.

[0052] For example, the initial position of the first droplet is on the surface of the driving electrode 11, and the photosensor is located directly above the first droplet. The first distance the photosensor moves is 4*D, then 4*D / D = 4. The first droplet has moved a distance of 4 electrode spacings. Therefore, the first position information of the first droplet in the first driving electrode is that the first droplet is on the surface of the driving electrode 15.

[0053] In one specific embodiment, the control component is further configured to: use the distance between the adjusted first position of the optical sensor and the first droplet as a fourth distance P1; after obtaining the mixed droplet, adjust the position of the optical sensor to the position closest to the mixed droplet to obtain an adjusted third position of the optical sensor; use the distance between the adjusted third position of the optical sensor and the mixed droplet as a fifth distance P2; obtain a first height H1 of the first droplet; obtain a second height H2 of the mixed droplet; subtract the first height H1 from the second height H2 as the increased height h after droplet mixing; adjust the height of the optical sensor according to the fourth distance P1, the fifth distance P2 and the increased height h; after adjusting the height of the optical sensor, obtain the adjusted fourth distance P1′ and the adjusted fifth distance P2′; and determine whether the first droplet and the second droplet have been successfully mixed according to the adjusted fourth distance P1′, the adjusted fifth distance P2′ and the increased height h.

[0054] like Figure 6 The diagram shown illustrates how to determine whether the first and second droplets have successfully mixed.

[0055] When the first and second droplets move independently, the distance from the first droplet to the photosensor is P1. The first and second droplets mix on the surface of the collecting electrode 44, resulting in a mixed droplet. This mixed droplet becomes larger, and its distance from the photosensor is now P2. At this point, the height of the vertical lifting rod needs to be adjusted, i.e., the height of the photosensor needs to be adjusted. One reason is that if the photosensor is too close to the droplet, the light intensity before and after mixing will be very strong, resulting in a very small difference in intensity. This places very high demands on the photosensor's accuracy and increases the risk of errors. Another reason is that if the photosensor is too far from the droplet, the light intensity before and after mixing will be very weak, again resulting in a very small difference in intensity. Even minor external interference can affect the judgment result. Therefore, adjusting the photosensor to a suitable height before determining whether the first and second droplets have successfully mixed is a crucial step in this design.

[0056] There are many ways to obtain the first height H1 of the first droplet and the second height H2 of the mixed droplet, including but not limited to the following:

[0057] Method 1

[0058] H1 and H2 are obtained using a rough calculation method.

[0059] Although the volume of the mixed liquids needs to be calculated precisely considering factors such as density, this method can roughly calculate it by considering the sum of the volumes of perfect spheres. Treating the droplets as spheres with their height as their diameter, the volume and height difference of the mixed droplets can also be roughly calculated. V=(4 / 3)ΠR 3 When the volume is doubled, R increases by 0.26 times, and the diameter also increases by 0.26 times. Droplet diameters are typically in the millimeter range. For example, assuming an average droplet size of 5mm, then H1 = 5mm, the diameter increases by the height by h = 1.3mm, and H2 = 6.3mm.

[0060] Method 2

[0061] H1 and H2 are obtained through simulation. Using COMSOL finite element simulation, the situation of droplets on a hydrophobic layer can be simulated based on the density, volume, and hydrophobic material of the liquid. This technology is an existing technology. With this technology, we can simulate the height H1 of a single droplet, as well as the height H2 of a mixed droplet.

[0062] In one specific embodiment, the control component is specifically configured to: set the first ratio value P1 / P2 obtained by dividing the fourth distance by the fifth distance as a first preset ratio value when the increased height h is greater than or equal to a preset value; calculate the fourth distance P1 based on the increased height h and the first preset ratio value; add the fourth distance P1 to the first height H1 as the adjusted height of the light sensor; adjust the height of the light sensor based on the adjusted height of the light sensor; calculate the adjusted fourth distance P1′ divided by the adjusted fifth distance P2′ to obtain a second ratio value; calculate the second ratio value divided by the first preset ratio value to obtain a third ratio value; determine whether the third ratio value is within a first preset range; if the third ratio value is within the first preset range, determine that the first droplet and the second droplet have successfully mixed; if the third ratio value is not within the first preset range, determine that the first droplet and the second droplet have not successfully mixed.

[0063] Since the inventive concept of this scheme is mainly based on the comparison of P1 and P2, we hope that P1 and P2 can present a multiple relationship; after the droplets are mixed, the volume increases and the height also increases. Let the increased height be h, then h + P2 = P1.

[0064] For example, given H1 = 5mm and h = 1.3mm, setting P1 / P2 to the first preset ratio of 2:1, and based on P1 / P2 = 2:1 and h + P2 = P1, we can calculate P2 = 1.3mm and P1 = 2.6mm. Therefore, the height of the lifting rod (actually referring to the sensor's transmission distance) is P1 + H1 = 2.6 + 5 = 7.6mm. Based on this height, preliminary adjustments to the lifting rod can be made. Of course, P1 / P2 can also be other ratios. For example, if P1 / P2 = 3, then we can calculate P2 = 0.65mm and P1 = 1.95mm.

[0065] The purpose of the above method is to roughly position the lifting rod, so that the data obtained based on this positioning is more intuitive. The main data obtained is P1 / P2. After adjusting the height of the optical sensor, the adjusted fourth distance P1′ and the adjusted fifth distance P2′ will change. The value of P1′ / P2′ will also fluctuate within a certain range compared with P1 / P2. If the fluctuation between P1′ / P2′ and P1 / P2 is between 10% and 20%, then it is determined that the first droplet and the second droplet have been successfully mixed.

[0066] However, the above method has certain problems. Regardless of whether P1 / P2 = 2:1 or P1 / P2 = 3:1, the calculated P2 value is relatively small. This requires relatively high accuracy from the sensor. Therefore, it is more reasonable to use this method when the P2 value is high. Since the values ​​of P1, P2 and h are related, a range can be set for the h value. When h is greater than or equal to the preset value (i.e., when the droplet size is large), the above method can be used directly to set the position of the lifting rod.

[0067] In one specific embodiment, the control component is specifically configured to: when the increased height h is less than a preset value, set the fourth proportional value obtained by dividing the increased height h by the fourth distance P1 as the second preset proportional value; calculate the fourth distance P1 based on the increased height h and the second preset proportional value; add the fourth distance P1 to the first height H1 as the adjusted height of the light sensor; adjust the height of the light sensor based on the adjusted height of the light sensor; calculate the increased height h divided by the adjusted fourth distance P1′ to obtain a fifth proportional value; determine whether the fifth proportional value is within the second preset range; if the fifth proportional value is within the second preset range, determine that the first droplet and the second droplet have successfully mixed; if the fifth proportional value is not within the second preset range, determine that the first droplet and the second droplet have not successfully mixed.

[0068] When the droplet size is small, the change in h value relative to P1′ is used as the criterion for judging whether the first and second droplets have been successfully mixed.

[0069] For example: H1 = 5mm, h = 1.3mm. First, preset h / P1 to the second preset ratio value of 30%, and calculate P1 = 4.4mm. Then, the height of the lifting rod (actually referring to the sensor's transmission distance) is P1 + H1 = 4.4 + 5 = 9.4mm. Based on this height, the height of the lifting rod can be adjusted. After adjusting the height of the optical sensor, the adjusted fourth distance P1′ will change. Calculate h / P1′. If h / P1′ is within the second preset range (between 0.3 and 0.5), then it is determined that the first and second droplets have successfully mixed.

[0070] In one specific embodiment, the optical sensor is configured to, within a preset time period, if it receives at least two successively decaying reflection intensity values, retain only the largest reflection intensity value; and based on the largest reflection intensity value, obtain a third distance between the first droplet and the current position of the optical sensor.

[0071] When a light sensor emits light vertically downwards, reflections occur at the liquid surface and on the electrode surface after passing through the liquid. The light sensor also receives multiple reflection results within a short period. This solution only requires the reflection intensity from the droplet surface, which is also the first result returned. This can be achieved through logic that if the sensor receives multiple progressively weakening reflections within a certain time window, only the strongest initial reflection will be retained.

[0072] In one specific embodiment, the control component is further configured to, after determining that the first droplet and the second droplet have successfully mixed, control each driving electrode in the first driving electrode to open or close, so that the mixed droplet moves to the mixed solution detection position on the surface of the first driving electrode and moves to the waste liquid tank after a preset time period; or, control each driving electrode in the second driving electrode to open or close, so that the mixed droplet moves to the mixed solution detection position on the surface of the second driving electrode and moves to the waste liquid tank after a preset time period.

[0073] In one specific embodiment, such as Figure 7 The diagram shown is a schematic of a droplet movement device based on vertical distance detection using an optical sensor. Figure 7 In the process, the mixed solution detection position is 55, and analytical equipment, such as a spectrometer, is located near position 55. The waste liquid tank is 66. After the droplets fuse, a reaction will occur. After a period of time to allow the reaction to be complete, the droplets are moved to position 55, where analytical instruments, such as a spectrometer, are located to analyze the reacted solution and record the data. Then, the droplets are moved to position 66, which is the waste liquid tank. The entire process is then complete.

[0074] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0075] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A droplet movement device based on vertical distance detection using an optical sensor, characterized in that, It includes a light sensor, a drive electrode assembly, and a control component; the light sensor is mounted on the robotic arm. The control component is used to control the movement of the robotic arm to move the photosensor on a plane parallel to the contact plane, wherein the contact plane is the surface in contact with the droplet and the drive electrode assembly; adjust the position of the photosensor to the position closest to the droplet to obtain the adjusted position of the photosensor; determine the distance the photosensor has moved during the movement of the droplet based on the adjusted position; obtain the position information of the droplet in the drive electrode assembly based on the distance the photosensor has moved; and control each drive electrode in the drive electrode assembly to open or close based on the position information to allow the droplet to move on the surface of the drive electrode assembly. The driving electrode set includes a first driving electrode and a second driving electrode; the first driving electrode and the second driving electrode share a common driving electrode, which is used as a collecting electrode; the droplet includes a first droplet and a second droplet; The control component is specifically configured to control the movement of the robotic arm to move the photosensor on a plane parallel to the first contact plane, wherein the first contact plane is the surface in contact between the first droplet and the first driving electrode; adjust the position of the photosensor to be closest to the first droplet, thereby obtaining an adjusted first position of the photosensor; determine a first distance the photosensor moves based on the adjusted first position during the movement of the first droplet; obtain first position information of the first droplet in the first driving electrode based on the first distance the photosensor moves; and control each driving electrode in the first driving electrode to open or close based on the first position information, so that the first droplet moves on the surface of the first driving electrode until the first droplet moves to the surface of the collecting electrode. The control component is specifically used to control the movement of the robotic arm to move the photosensor on a plane parallel to the second contact plane, wherein the second contact plane is the surface in contact with the second droplet and the second driving electrode; adjust the position of the photosensor to the position closest to the second droplet to obtain the adjusted second position of the photosensor; determine the second distance the photosensor moves by the adjusted second position during the movement of the second droplet; obtain the second position information of the second droplet in the second driving electrode based on the second distance the photosensor moves; and control each driving electrode in the second driving electrode to open or close according to the second position information, so that the second droplet moves on the surface of the second driving electrode until the second droplet moves to the surface of the collecting electrode. The control component is specifically configured to mix the first droplet and the second droplet on the surface of the collecting electrode to obtain a mixed droplet; specifically configured to, when the first droplet is in its initial position, acquire a third distance between the first droplet and the current position of the photosensitive sensor; control the photosensitive sensor to move at a preset interval on a plane parallel to the first contact plane, centered on the current position of the photosensitive sensor; and reacquire the third distance between the positions of the first droplet and the photosensitive sensor after the movement; using the position of the photosensitive sensor corresponding to the minimum third distance as the center, reduce the preset interval according to a preset rule, and then return to execute the step of controlling the photosensitive sensor to move at a preset interval on a plane parallel to the first contact plane, until the number of executions equals the preset number of executions, and then take the position of the photosensitive sensor as the adjusted first position of the photosensitive sensor.

2. The droplet movement device based on vertical distance detection using an optical sensor according to claim 1, characterized in that, The control component is specifically used to, during the movement of the first droplet, use the distance between two adjacent adjusted first positions as the electrode spacing between two adjacent driving electrodes in the first driving electrode path.

3. The droplet movement device based on vertical distance detection using an optical sensor according to claim 2, characterized in that, The control component is specifically used to calculate the quotient obtained by dividing the first distance moved by the optical sensor by the electrode spacing, and to obtain the first position information of the first droplet in the first driving electrode based on the quotient.

4. The droplet movement device based on vertical distance detection using an optical sensor according to claim 1, characterized in that, The control component is further configured to: use the distance between the adjusted first position of the optical sensor and the first droplet as a fourth distance; after obtaining the mixed droplet, adjust the position of the optical sensor to the position closest to the mixed droplet to obtain the adjusted third position of the optical sensor; use the distance between the adjusted third position of the optical sensor and the mixed droplet as a fifth distance; obtain the first height of the first droplet; obtain the second height of the mixed droplet; subtract the first height from the second height as the increased height after droplet mixing; adjust the height of the optical sensor according to the fourth distance, the fifth distance, and the increased height; after adjusting the height of the optical sensor, obtain the adjusted fourth distance and the adjusted fifth distance; and determine whether the first droplet and the second droplet have been successfully mixed according to the adjusted fourth distance, the adjusted fifth distance, and the increased height.

5. A droplet moving device based on vertical distance detection using an optical sensor according to claim 4, characterized in that, The control component is specifically configured to: when the increased height is greater than or equal to a preset value, set the first ratio value obtained by dividing the fourth distance by the fifth distance as a first preset ratio value; calculate the fourth distance based on the increased height and the first preset ratio value; use the sum of the fourth distance and the first height as the adjusted height of the light sensor; and adjust the height of the light sensor based on the adjusted height of the light sensor. Calculate the adjusted fourth distance divided by the adjusted fifth distance to obtain a second ratio value; calculate the second ratio value divided by the first preset ratio value to obtain a third ratio value; determine whether the third ratio value is within a first preset range; if the third ratio value is within the first preset range, determine that the first droplet and the second droplet have successfully mixed; if the third ratio value is not within the first preset range, determine that the first droplet and the second droplet have not successfully mixed.

6. The droplet moving device based on vertical distance detection using an optical sensor according to claim 4, characterized in that, The control component is specifically configured to: when the increased height is less than a preset value, set a fourth ratio value obtained by dividing the increased height by the fourth distance as a second preset ratio value; calculate the fourth distance based on the increased height and the second preset ratio value; add the fourth distance to the first height as the adjusted height of the light sensor; adjust the height of the light sensor based on the adjusted height; calculate the increased height divided by the adjusted fourth distance to obtain a fifth ratio value; determine whether the fifth ratio value is within a second preset range; if the fifth ratio value is within the second preset range, determine that the first droplet and the second droplet have successfully mixed; if the fifth ratio value is not within the second preset range, determine that the first droplet and the second droplet have not successfully mixed.

7. A droplet moving device based on vertical distance detection using an optical sensor according to claim 1, characterized in that, The optical sensor is configured to, within a preset time period, if it receives at least two successively decreasing reflection intensity values, retain only the largest reflection intensity value; and based on the largest reflection intensity value, obtain a third distance between the first droplet and the current position of the optical sensor.

8. A droplet movement device based on vertical distance detection using an optical sensor according to any one of claims 4 to 6, characterized in that, The control component is further configured to, after determining that the first droplet and the second droplet have successfully mixed, control each driving electrode in the first driving electrode to open or close, so that the mixed droplet moves on the surface of the first driving electrode to the mixed solution detection position and moves to the waste liquid tank after a preset time period; or, control each driving electrode in the second driving electrode to open or close, so that the mixed droplet moves on the surface of the second driving electrode to the mixed solution detection position and moves to the waste liquid tank after a preset time period.

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