Liquid quantity detection system based on capacitive sensing array

Abstract

The invention provides a liquid quantity detection system based on a capacitive sensing array, and relates to the technical field of liquid quantity detection. According to the system, a capacitive sensor array is arranged in a supporting shell; the supporting shell is used for supporting the capacitive sensor array, so that the capacitive sensor array clings to the outer surface of the tubular container; a solution with the liquid amount to be detected is contained in the tubular container; the control module is connected with the capacitive sensor array; the control module is used for controlling each excitation electrode in a plurality of excitation electrodes included in the capacitive sensor array based on a mutual capacitance measurement method, and sending excitation signals to a plurality of detection electrodes included in the capacitive sensor array; the capacitive sensor array is used for outputting capacitance values between the excitation electrodes and the corresponding detection electrodes under the action of excitation signals to obtain a plurality of capacitance values; the data calculation module is used for calculating the height of the liquid with the liquid amount to be detected in the tubular container according to the capacitance values. The accuracy of liquid amount detection is improved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of liquid volume detection, and more particularly, to a liquid volume detection system based on a capacitive sensing array. Background Art

[0002] In the field of medical testing, in order to achieve the detection of multiple blood indicators, samples need to be centrifuged, and then the content of serum or plasma after centrifugation in a blood collection tube is detected. When an anticoagulant is added to the blood in the blood collection tube, the upper layer of the centrifuged blood is plasma and the lower layer is red blood cells; if no anticoagulant is added to the blood in the blood collection tube, the upper layer of the centrifuged blood is serum and the lower layer is a blood clot.

[0003] With the automation of medical testing, routine blood tests are usually completed by machines, and a key step is to detect the serum volume or plasma volume in a blood collection tube. Traditional methods for detecting serum volume and plasma volume mainly rely on optical imaging technology. Although it has the advantages of high speed and quickness, it is easily affected by the occlusion of multiple label papers, resulting in poor detection effects. Summary of the Invention

[0004] In view of this, the present disclosure provides a liquid volume detection system based on a capacitive sensing array.

[0005] One aspect of the present disclosure provides a liquid volume detection system based on a capacitive sensing array. The liquid volume detection system includes: a capacitive sensor array, a support housing, a control module, and a data calculation module; the capacitive sensor array is disposed inside the support housing; the support housing is used to support the capacitive sensor array so that the capacitive sensor array is in close contact with the outer surface of a tubular container; a solution with a liquid volume to be detected is contained in the tubular container; the control module is connected to the capacitive sensor array; the control module is used to control each of a plurality of excitation electrodes included in the capacitive sensor array to send an excitation signal to a plurality of detection electrodes included in the capacitive sensor array based on a mutual capacitance measurement method; the capacitive sensor array is used to output capacitance values between the excitation electrodes and the corresponding detection electrodes under the action of the excitation signal to obtain a plurality of capacitance values; the data calculation module is used to calculate the height of the liquid with the liquid volume to be detected in the tubular container according to the plurality of capacitance values.

[0006] According to an embodiment of the present disclosure, the capacitive sensor array includes two sensor array units with the same structure; the two sensor array units are disposed opposite to each other; each of the sensor array units includes a plurality of electrode units; when the capacitive sensor array is in close contact with the outer surface of the tubular container, the plurality of electrode units are uniformly distributed along the axial direction of the tubular container.

[0007] According to an embodiment of the present disclosure, each of the above electrode units includes a capacitive sensing electrode and a lead electrode; a wire arranged in a serpentine shape is included between the capacitive sensing electrode and the lead electrode; the capacitive sensing electrode is supported by the support housing and closely adheres to the inner surface of the support housing; the lead electrodes are respectively connected to the control module and the data calculation module; the lead electrode is used to be connected to a DC excitation voltage source or the data calculation module under the control of the control module; wherein, when the lead electrode is connected to the DC excitation voltage source, the capacitive sensing electrode connected to the lead electrode is an excitation electrode; when the lead electrode is connected to the data calculation module, the capacitive sensing electrode connected to the lead electrode is a detection electrode.

[0008] According to an embodiment of the present disclosure, the liquid volume detection system further includes a wire fixator; one end of the wire fixator is fixed on the outer surface of the support housing; a wire fixing groove is provided at the other end of the wire fixator; the connection wires between the lead electrode and the control module and between the lead electrode and the data calculation module are fixed in the wire fixing groove.

[0009] According to an embodiment of the present disclosure, when the lead electrode is not connected to the DC excitation voltage source and is not connected to the data calculation module, the lead electrode is connected to the ground under the control of the control module.

[0010] According to an embodiment of the present disclosure, the support housing sequentially includes an elastic support body and a metal shielding shell from the inside to the outside; a first groove is provided in the metal shielding shell; the first groove is a cylindrical structure; the elastic support body is arranged in the first groove; the outer surface of the elastic support body is closely attached to the surface of the first groove; the capacitive sensor array is arranged inside the elastic support body; the capacitive sensor array is supported by the elastic support body and closely adheres to the outer surface of the tubular container; the axial direction of the first groove is the same as the axial direction of the tubular container.

[0011] According to an embodiment of the present disclosure, a second groove is provided inside the elastic support body; the second groove is a cylindrical structure; the curvature of the second groove is the same as the curvature of the outer surface of the tubular container; when the tubular container is placed in the second groove, the axial direction of the tubular container is the same as the axial direction of the second groove, and the length of the tubular container is less than the length of the second groove.

[0012] According to an embodiment of the present disclosure, the data calculation module includes a data acquisition unit and a calculation unit; the data acquisition unit is used to acquire a plurality of capacitance values output by the capacitive sensor array; the calculation unit is used to calculate the height of the liquid to be detected in the tubular container according to the plurality of capacitance values.

[0013] According to an embodiment of the present disclosure, the above-mentioned sensor array unit includes: a flexible substrate layer; a metal thin film layer including a plurality of electrode units formed on the flexible substrate layer; and a packaging layer on the flexible substrate layer covering the metal thin film layer.

[0014] According to an embodiment of the present disclosure, the above-mentioned control module includes a channel switching unit and a controller;

[0015] One end of the above-mentioned channel switching unit is connected to the above-mentioned lead electrode, and the other end is connected to the above-mentioned DC excitation voltage source or the above-mentioned data calculation module;

[0016] The above-mentioned controller is used to control the above-mentioned channel switching unit so that the above-mentioned lead electrode is connected to the above-mentioned DC excitation voltage source or the above-mentioned data calculation module.

[0017] According to an embodiment of the present disclosure, when performing liquid volume detection, the capacitive sensor array is supported by the support housing so that the capacitive sensor array is closely attached to the outer surface of the tubular container, realizing non-contact measurement of the liquid to be detected in the tubular container; based on the mutual capacitance measurement method, by using the liquid to be detected in the tubular container as a dielectric material, a plurality of capacitance values between the excitation electrode and the corresponding detection electrode at different positions of the tubular container are measured, and the height of the liquid to be detected in the tubular container is calculated by calculating the plurality of capacitance values, realizing the measurement of the liquid volume of the liquid to be detected in the tubular container by the capacitive sensor array; because the electromagnetic characteristics of the capacitive sensing array are utilized and the mutual capacitance detection method is adopted, at least partially, the technical problem of low measurement accuracy of the liquid level height under the occlusion of multiple layers of label paper is overcome, and thus the technical effect of improving the accuracy of liquid volume detection is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Through the following description of the embodiments of the present disclosure with reference to the drawings, the above and other objects, features and advantages of the present disclosure will become clearer. In the drawings:

[0019] Figure 1 Schematically shows a structural diagram of a liquid volume detection system based on a capacitive sensing array according to an embodiment of the present disclosure;

[0020] Figure 2 Schematically shows an external view of the positional relationship between a capacitive sensor array and a support housing according to an embodiment of the present disclosure;

[0021] Figure 3 Schematically shows an internal view of the positional relationship between a capacitive sensor array and a support housing according to an embodiment of the present disclosure;

[0022] Figure 4 Schematically shows a structural diagram of a capacitive sensing array according to an embodiment of the present disclosure;

[0023] Figure 5 Schematically shows a schematic diagram of the detection principle of a liquid volume detection system based on a capacitive sensing array according to an embodiment of the present disclosure;

[0024] Figure 6 Schematically shows a schematic diagram of the test process of a liquid volume detection system based on a capacitive sensing array according to an embodiment of the present disclosure; and

[0025] Figure 7 Schematically shows a schematic diagram of the predicted result of the liquid level height of a liquid volume detection system based on a capacitive sensing array according to an embodiment of the present disclosure. Detailed implementation manners

[0026] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present disclosure. In the following detailed description, for the sake of explanation, many specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure. However, it is obvious that one or more embodiments can be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily obscuring the concepts of the present disclosure.

[0027] The terms used herein are merely for describing specific embodiments and are not intended to limit the present disclosure. The terms "including", "comprising" and the like used herein indicate the presence of the described features, steps, operations and / or components, but do not exclude the presence or addition of one or more other features, steps, operations or components.

[0028] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0029] In the case of using expressions such as "at least one of A, B, and C", generally, it should be interpreted according to the meaning commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.).

[0030] In the embodiments of the present disclosure, in aspects such as the collection, update, analysis, processing, use, transmission, provision, disclosure, storage, etc. of the involved data (for example, including but not limited to user personal information), they all comply with the provisions of relevant laws and regulations, are used for legal purposes, and do not violate public order and good customs. In particular, necessary measures are taken for user personal information to prevent illegal access to user personal information data and to safeguard user personal information security and network security.

[0031] In the embodiments of the present disclosure, before obtaining or collecting user personal information, the authorization or consent of the user is obtained.

[0032] Due to advantages such as low cost and high sensitivity, capacitive sensors show good application prospects in non-contact liquid level detection. The basic principle of a capacitive sensor for measuring liquid level is to detect the liquid level height by measuring the change in capacitance value caused by the change in the liquid level of the liquid (as a dielectric material), and convert this capacitance change into an electrical signal output. Currently, capacitive sensors used for liquid level measurement are mainly divided into two types: contact type and non-contact type. Contact capacitive sensors need to be immersed in the liquid for measurement, which is easy to contaminate the sample and is not suitable especially for medical applications. In contrast, non-contact capacitive sensors effectively avoid this problem and provide a safer and more reliable solution for liquid volume detection through a non-invasive measurement method.

[0033] However, non-contact capacitive sensors still face many challenges in practical applications. For example, by measuring the change in liquid level in a liquid storage device through capacitance change and combining components such as a capacitance-driven sampling circuit and an LC resonance circuit, precise measurement of the liquid level is achieved. Although this method is of great significance in liquid level detection such as sample diluent in a blood analyzer, it does not propose an effective solution to the problem of dealing with the coexistence of multiple liquids in serum volume or plasma volume detection.

[0034] In practical applications, the detection of serum volume and plasma volume not only requires high-precision liquid level measurement, but also needs to be able to accurately distinguish the interfaces between serum and plasma and other liquids, provide accurate liquid volume information, and meet the requirements of automated collection and processing. However, existing non-contact capacitive sensors still have many deficiencies in the detection of serum volume and plasma volume. They often can only identify the height of a single liquid and cannot accurately identify the interfaces between serum or plasma and other liquids when serum or plasma coexists with other liquids, thus unable to obtain the liquid level height of serum or plasma. In addition, some non-contact capacitive sensors also have obvious shortcomings in measurement accuracy and anti-interference ability, which further limits their application in the detection of serum volume and plasma volume.

[0035] In view of the various limitations of existing liquid level detection methods in the detection of serum volume and plasma volume, there is an urgent need for a liquid volume detection system suitable for high-precision, high-reliability, and non-contact detection of serum and plasma volumes in the scenario of medical test automation.

[0036] Embodiments of the present disclosure provide a liquid volume detection system based on a capacitive sensing array, including: a capacitive sensor array, a support housing, a control module, and a data calculation module; the capacitive sensor array is disposed inside the support housing; the support housing is used to support the capacitive sensor array so that the capacitive sensor array is closely attached to the outer surface of the tubular container; a solution with a liquid volume to be detected is contained in the tubular container; the control module is connected to the capacitive sensor array; the control module is configured to control each of the multiple excitation electrodes included in the capacitive sensor array to send an excitation signal to the multiple detection electrodes included in the capacitive sensor array based on the mutual capacitance measurement method; the capacitive sensor array is configured to output the capacitance value between the excitation electrode and the corresponding detection electrode under the action of the excitation signal to obtain multiple capacitance values; the data calculation module is configured to calculate the height of the liquid with the liquid volume to be detected in the tubular container according to the multiple capacitance values.

[0037] According to the embodiments of the present disclosure, when performing liquid volume detection, the capacitive sensor array is supported by the support housing so that the capacitive sensor array is closely attached to the outer surface of the tubular container, realizing non-contact measurement of the liquid to be detected in the tubular container; based on the mutual capacitance measurement method, by using the liquid to be detected in the tubular container as a dielectric material, multiple capacitance values between the excitation electrode and the corresponding detection electrode at different positions of the tubular container are measured, and by calculating the height of the liquid with the liquid volume to be detected in the tubular container from the multiple capacitance values, the capacitive sensor array realizes the measurement of the liquid volume of the liquid to be detected in the tubular container; because the electromagnetic characteristics of the capacitive sensing array are utilized and the mutual capacitance detection method is adopted, at least partially, the technical problem of low measurement accuracy of the liquid level height under the occlusion of multiple label papers is overcome, and thus the technical effect of improving the accuracy of liquid volume detection is achieved.

[0038] Figure 1 The structural schematic diagram of the liquid volume detection system based on the capacitive sensing array according to the embodiments of the present disclosure is schematically shown.

[0039] As Figure 1As shown in the figure, a liquid volume detection system based on a capacitive sensing array includes: a capacitive sensor array, a support housing 6, a control module 1, and a data calculation module 2. The capacitive sensor array is disposed inside the support housing 6; the support housing 6 is used to support the capacitive sensor array so that the capacitive sensor array is in close contact with the outer surface of the tubular container 5; a solution with a liquid volume to be detected is contained in the tubular container 5; the control module 1 is connected to the capacitive sensor array; the control module 1 is configured to control each of the multiple excitation electrodes included in the capacitive sensor array to send an excitation signal to the multiple detection electrodes included in the capacitive sensor array based on the mutual capacitance measurement method; the capacitive sensor array is configured to output the capacitance value between the excitation electrode and the corresponding detection electrode under the action of the excitation signal to obtain a plurality of capacitance values; the data calculation module 2 is configured to calculate the height of the liquid with the liquid volume to be detected in the tubular container 5 according to the plurality of capacitance values.

[0040] According to an embodiment of the present disclosure, the liquid volume detection system based on the capacitive sensing array further includes a mounting block 3. The mounting block 3 is fixed on the support housing 6. The mounting block 3 is used to assemble the support housing 6 to application scenarios such as a slide rail and a robotic arm. A clamp 4 for holding the tubular container 5 is provided at the top of the tubular container 5 for moving the tubular container 5. With such a setting method, it is convenient to realize the automatic measurement of the liquid height of the liquid with the liquid volume to be detected in the tubular container 5. The data calculation module analyzes the plurality of capacitance values based on a preset algorithm model to obtain the height of the liquid with the liquid volume to be detected in the tubular container 5.

[0041] Through the integration of the high-sensitivity measurement of the capacitive sensing array and the algorithm model, the present disclosure can accurately identify the liquid volume of serum and plasma, and its detection accuracy has been significantly improved compared with traditional optical and ultrasonic detection methods. Especially compared with the traditional optical detection method, the present system utilizes the electromagnetic characteristics of the capacitive sensing array, and even under complex conditions where there are multiple layers of label papers covering the surface of the blood collection tube, it can achieve high-precision and non-contact measurement of the liquid level height, effectively overcoming the defect that the traditional optical imaging technology has poor detection effect due to occlusion, and thus showing more excellent performance in various application scenarios.

[0042] Figure 2 An external schematic diagram schematically showing the positional relationship between the capacitive sensor array and the support housing according to an embodiment of the present disclosure is shown.

[0043] As Figure 2As shown in the figure, the support housing includes an elastic support body and a metal shielding case 10. The elastic support body is installed in the installation groove of the metal shielding case 10. Its inner surface is an arched structure with the same curvature as that of the tubular container, and the length of the installation groove is less than the length of the metal shielding case 10. The metal shielding case 10 is used to shield electromagnetic interference outside the measurement area. The internal installation groove thereof is cylindrical, and a wire fixer 8 for fixedly connecting a wire 7 is arranged on the outer surface. The metal shielding case 10 is made of aluminum alloy material and can be machined by a numerical control machine tool. The connecting wire 7 is connected to the capacitance sensing array and is used to transmit the data collected by the capacitance sensing array inside the support housing. Figure 2 The mounting block 3, the fixture 4 and the tubular container 5 in Figure 1 are the same as those described above and will not be elaborated here.

[0044] Figure 3 The internal schematic diagram schematically shows the positional relationship between the capacitance sensor array and the support housing according to an embodiment of the present disclosure.

[0045] As Figure 3 shown in the figure, the support housing 6 sequentially includes an elastic support body 9 and a metal shielding case 10 from the inside to the outside; a first groove is provided inside the metal shielding case 10; the first groove is a cylindrical structure; the elastic support body 9 is arranged in the first groove; the outer surface of the elastic support body 9 is closely attached to the surface of the first groove; the capacitance sensor array is arranged inside the elastic support body 9; the capacitance sensor array is supported by the elastic support body 9 and closely adheres to the outer surface of the tubular container; the axial direction of the first groove is the same as the axial direction of the tubular container. The first groove is the installation groove of the metal shielding case 10.

[0046] A second groove is provided inside the elastic support body 9; the second groove is a cylindrical structure; the curvature of the second groove is the same as the curvature of the outer surface of the tubular container; when the tubular container is placed in the second groove, the axial direction of the tubular container is the same as the axial direction of the second groove, and the length of the tubular container is less than the length of the second groove.

[0047] According to an embodiment of the present disclosure, the metal shielding case 10 can be divided into two parts, including a first metal shielding case and a second metal shielding case. The first metal shielding case and the second metal shielding case are oppositely arranged to form the metal shielding case 10. The structures of the first metal shielding case and the second metal shielding case can be the same. The grooves inside the first metal shielding case and the grooves inside the second metal shielding case form a first groove, serving as the installation groove for the elastic support 9. The structures of the grooves inside the first metal shielding case and the grooves inside the second metal shielding case can be the same. The elastic support 9 can include two parts, one part is a first elastic support and a second elastic support. The first elastic support and the second elastic support are oppositely arranged to form the elastic support 9; the structures of the first elastic support and the second elastic support can be the same. The grooves inside the first elastic support and the grooves inside the second elastic support form a second groove; the structures of the grooves inside the first elastic support and the grooves inside the second elastic support can be the same. For example, the inner surfaces of the grooves inside the first metal shielding case, the grooves inside the second metal shielding case, the grooves inside the first elastic support, and the grooves inside the second elastic support are all arched structures, and the curvature is the same as that of the tubular container.

[0048] According to an embodiment of the present disclosure, the wire fixator 8 can include a first wire fixator and a second wire fixator. The first wire fixator is fixed on the outer surface of the first metal shielding case, and the second wire fixator is fixed on the outer surface of the second metal shielding case.

[0049] The capacitance sensor array includes two sensor array units with the same structure; the two sensor array units are oppositely arranged; each sensor array unit includes a plurality of electrode units; when the capacitance sensor array is closely attached to the outer surface of the tubular container, the plurality of electrode units are uniformly distributed along the axial direction of the tubular container. Each electrode in the plurality of electrode units of one sensor array unit has a unique corresponding electrode unit in the plurality of electrode units of the other sensor array unit, so that the dielectric constant information intensity is uniform at each part of the measured area of the tubular container by the capacitance sensor array, thereby enabling the electrode units to obtain accurate capacitance value data.

[0050] According to an embodiment of the present disclosure, the first elastic support is installed in the groove inside the first support case; the second elastic support is installed in the groove inside the second support case; one of the sensor array units is installed in the groove inside the first elastic support, and the other sensor array unit is installed in the groove inside the second elastic support. The axes of the first groove, the second groove, and the tubular container coincide.

[0051] Each electrode unit includes a capacitive sensing electrode 11 and a lead electrode 13; between the capacitive sensing electrode 11 and the lead electrode 13, there is a wire arranged in a serpentine shape, called the serpentine wire 12; the capacitive sensing electrode 11 is supported by the support housing and closely adheres to the inner surface of the support housing; the lead electrodes 13 are respectively connected to the control module and the data calculation module; the lead electrode 13 is used to connect to the DC excitation voltage source or the data calculation module under the control of the control module; wherein, when the lead electrode 13 is connected to the DC excitation voltage source, the capacitive sensing electrode 11 connected to the lead electrode 13 is the excitation electrode; when the lead electrode 13 is connected to the data calculation module, the capacitive sensing electrode 11 connected to the lead electrode 13 is the detection electrode. When the lead electrode 13 is not connected to the DC excitation voltage source and is not connected to the data calculation module, the lead electrode 13 is connected to the ground under the control of the control module.

[0052] According to an embodiment of the present disclosure, the edges of the grooves inside the first elastic support and the grooves inside the second elastic support can be changed to rounded corners to increase the service life of the capacitive sensing electrodes.

[0053] The connecting wire 7 includes a first connecting wire and a second connecting wire; the first connecting wire is connected to the lead electrode of one of the sensor array units and fixed by the first wire fixer; the second connecting wire is connected to the lead electrode of the other sensor array unit and fixed by the second wire fixer.

[0054] One end of the wire fixer of the liquid volume detection system based on the capacitive sensing array is fixed on the outer surface of the support housing; the other end of the wire fixer is provided with a wire fixing groove; the connecting wires between the lead electrode and the control module and between the lead electrode and the data calculation module are fixed in the wire fixing groove.

[0055] For example, when the tubular container is a blood collection tube, it includes a rubber stopper 51 and a pipeline. Inside the pipeline, the collected blood with the liquid volume to be detected is placed. When no anticoagulant is added, the blood with the liquid volume to be detected in the pipeline is divided into two layers, namely serum 52 and blood clot 53. The liquid level height of the serum 52 is detected by applying the liquid volume detection system based on the capacitive sensing array, so that the blood collection tube is wrapped by two sensor array units, and the liquid volume information of the blood with the liquid volume to be detected in the blood collection tube is calculated according to multiple capacitance values.

[0056] Figure 4 Schematically shows a structural diagram of a capacitive sensing array according to an embodiment of the present disclosure.

[0057] As Figure 4 shown, each sensor array unit includes: a flexible base layer; a metal thin film layer including a plurality of electrode units formed on the flexible base layer; and a packaging layer covering the metal thin film layer on the flexible base layer.

[0058] The multiple electrode units included in each sensor array unit are fabricated in an integrally formed manner. For example, if a sensor array unit includes ten electrode units, the ten electrode units are fabricated simultaneously, and the surface of the sensor array unit is encapsulated with Parylene material.

[0059] According to an embodiment of the present disclosure, the preparation process of the sensor array unit may include operations S11 to S15.

[0060] In operation S11, the pattern of the electrode unit is designed. In Figure 4 , the electrode unit is composed of a capacitive sensing electrode 11 and a lead electrode 13. Since the capacitive sensing electrode 11 is used to wrap the tubular container, the capacitive sensing electrode 11 can be designed as a relatively large-area square structure or a structure of other shapes. To reduce the volume of the support housing, the lead electrode 13 can be designed as a relatively small-area square structure or a structure of other shapes. The capacitive sensing electrode 11 and the lead electrode 13 are connected by a serpentine wire 12. The serpentine wire 12 structure can effectively prevent the conductive layer from breaking during the stretching process, significantly improving the mechanical stability and durability of the device.

[0061] In operation S12, a polyimide (PI) polymer thin film is selected as the material of the flexible substrate layer. This material has excellent high mechanical strength, thermal stability, and chemical stability. The thickness of the flexible substrate layer can be optimized according to the specific application scenario requirements for flexibility of the capacitive sensing unit. For example, the thickness of the flexible substrate layer is less than 2 μm.

[0062] In operation S13, the PI film is cut to the required size. For example, if the capacitive sensing unit includes ten electrode units evenly distributed, the required size is the size required when the ten electrode units evenly distributed are integrated. The PI film is fixed flat on the glass substrate using a special tape for PI film. Subsequently, the pre-prepared mask is accurately aligned through the PI film tape and fixed on the surface of the PI film. The pattern on the mask is the shape of ten electrode units evenly distributed, and the shape of each electrode unit is the pattern of the electrode unit designed in (1). Accurate alignment means that each pair of facing electrode units should be aligned. Each pair of facing electrode units means that each electrode unit in one sensor array unit has a facing electrode unit in another sensor array unit.

[0063] In operation S14, a Ti / Cu double-layer metal film is sequentially deposited on the surface of the PI film using an electron beam evaporation technique. The specific process parameters are: first, a 10-nm-thick Ti film is deposited as an adhesion layer, and then a 500-nm-thick Cu film is deposited thereon as a conductive layer.

[0064] In operation S15 , after the metal layer deposition is completed, the mask is removed, and the PI film prepared with the capacitive sensing electrodes, lead electrodes and serpentine wire structure is peeled off from the glass substrate to obtain a complete flexible sensor array unit device.

[0065] According to an embodiment of the present disclosure, the preparation process of the elastic support body may include operations S21 to S24.

[0066] In operation S21 , a reverse mold cavity of the elastic support body is machined using a CNC machine tool according to the desired three-dimensional structural characteristics of the elastic support body.

[0067] In operation S22, polydimethylsiloxane (PDMS) prepolymer and curing agent are accurately weighed in a mass ratio of 10:1. Stir until the mixture is homogeneous. The mixture is then placed in a vacuum drying oven at -0.1 MPa for 15-20 minutes to remove air bubbles.

[0068] In operation S23, the degassed PDMS mixture is slowly injected into the pre-prepared mold cavity. The filled mold is transferred to a constant temperature oven and cured at 80°C for 2 hours to ensure that the PDMS is completely cross-linked.

[0069] In operation S24, after the mold is cooled to room temperature, the solidified elastic support body is carefully removed from the mold, and the surface integrity of the product is checked to remove any flash or burrs that may exist, thereby obtaining a final usable elastic support body.

[0070] Figure 5 The following schematically shows a detection principle diagram of a liquid quantity detection system based on a capacitive sensing array according to an embodiment of the present disclosure.

[0071] like Figure 5 As shown, the data calculation module includes a data acquisition unit 503 and a calculation unit 504. The data acquisition unit 503 is used to collect multiple capacitance values output by the capacitive sensor array. The calculation unit 504 is used to calculate the height of the liquid to be detected within the tubular container based on the multiple capacitance values. The control module includes a channel switching unit 501 and a controller 502. One end of the channel switching unit 501 is connected to the lead electrode and the other end is connected to a DC excitation voltage source or the data calculation module. The controller 502 is used to control the channel switching unit 501 so that the lead electrode is connected to the DC excitation voltage source or the data calculation module. The DC excitation voltage source is used to provide an excitation signal for the capacitive sensor array.

[0072] According to an embodiment of the present disclosure, the channel switching unit 501 may be a multiplexer. The data acquisition unit 503 may be a capacitance acquisition chip and a microcontroller. For example, the capacitance acquisition chip is a high-precision digital capacitance sensing chip MDC02 / MDC04. The multiplexer selects different electrode pairs of the capacitance sensing array and transmits the capacitance signals output by the selected electrode pairs to the capacitance acquisition chip. The capacitance acquisition chip converts the acquired capacitance signals into voltage signals. The microcontroller may process the voltage signals and convert them into capacitance values. The calculation unit 504 may be a computer. The microcontroller transmits multiple capacitance values to the calculation unit 504 through methods such as USB or serial port. The calculation unit 504 performs normalization processing on the capacitance matrix to eliminate errors and background noise, and obtains high-precision liquid level height information by analyzing the eigenvalue changes of the capacitance matrix and combining with an algorithm model. The controller 502 may use a microcontroller to implement functions. That is to say, the controller can not only control the channel switching unit 501, but also process the voltage signals output by the capacitance acquisition chip and convert them into capacitance values.

[0073] Based on the mutual capacitance measurement technology, the channel switching unit 501 controls the lead electrodes of the capacitance sensing array to be connected to the DC excitation voltage source or to the data calculation module, so as to make the capacitance sensing electrode be the excitation electrode or the detection electrode. The channel switching unit 501 may control the lead electrodes to be connected to the DC excitation voltage source or to the data calculation module according to a preset order or rule. For example, when the capacitance sensing electrode of the electrode unit N in the sensor array unit M = 1 is the excitation electrode, the other electrode units in the sensor array unit M = 1 are grounded, and all the capacitance sensing electrodes in the sensor array unit M = 2 are detection electrodes, and the data of the lead electrodes connected to the detection electrodes are collected. Traverse all the electrode units in the sensor array unit M = 1 as the excitation electrodes to obtain multiple capacitance values, and the multiple capacitance values may form a capacitance matrix. Taking the case where the sensor array unit includes ten electrode units as an example, the following capacitance matrix C is obtained.

[0074] 。

[0075] In the capacitance matrix C, C ij 's value may represent the capacitance value of the capacitance formed by the excitation electrode i and the detection electrode j. Among them, the value range of i is 1, 2,... 10; the value range of j is 1, 2,... 10; F = 10.

[0076] Based on the mutual capacitance measurement technology, each electrode unit in the capacitance sensing array can be used as an excitation electrode or a detection electrode, and the controller controls the channel switching unit to make the electrode unit be an excitation electrode or a detection electrode. High-precision measurement is achieved by rotating the excitation electrode and the detection electrode of the capacitance sensing array.

[0077] For example, a pair of electrode units from one of the sensor array units is randomly selected. The first electrode is used as the excitation electrode, and a DC excitation voltage with an amplitude of U is applied. The second electrode is used as the detection electrode to receive the signal. The remaining electrodes are grounded to eliminate external interference. The mutual capacitance value Cmn between the electrode pair is obtained through the data acquisition unit, where m represents the excitation electrode number and n represents the detection electrode number. Each electrode is used as the excitation electrode in a preset order, and the remaining nine electrodes are used as detection electrodes to perform capacitance measurements. Specifically, when the mth electrode is used as the excitation electrode, the mutual capacitance values Cmn between it and the 1st to 10th (m≠n) electrodes are measured respectively. A total of 10×9=90 independent capacitance measurements are obtained, and the capacitance values of the two opposing electrodes are distributed on the diagonal positions of the data matrix. After structured processing, the measurement data is placed at the diagonal position of the capacitance matrix (m=n) by placing the capacitance values of two diametrically opposed capacitance sensing electrode pairs. This forms a 10×10 capacitance matrix C=[Cmn]. In this symmetric matrix, the diagonal elements represent the self-capacitance characteristics, while the off-diagonal elements Cmn (m≠n) reflect the mutual capacitance parameters. The mathematical symmetry Cmn=Cnm significantly improves data reliability.

[0078] The computer acquires capacitance data from the data acquisition unit via serial communication. The computer can implement data processing using various programming languages and software platforms to meet the needs of different users and development environments. For example, a support vector machine regression (SVR) algorithm can be used for data processing. The normalized capacitance matrix is input into a trained model, which can accurately identify the capacitance characteristics corresponding to different media (such as serum, plasma, and blood cells). Based on the input capacitance matrix data, the model uses its built-in algorithm and trained parameters to accurately calculate the height of the serum or plasma volume in the blood collection tube.

[0079] Figure 6 The figure schematically shows a test flow diagram of a liquid quantity detection system based on a capacitive sensing array according to an embodiment of the present disclosure.

[0080] like Figure 6 As shown, taking the tubular container as a blood collection tube and blood as a solution to be tested as an example, the test process includes operations S601 to S604.

[0081] In operation S601 , a standard blood collection tube is placed in a detection area of a capacitive sensing array.

[0082] The standard blood collection tube is accurately placed in the detection area surrounded by the capacitive sensing array, ensuring that the axis of the blood collection tube coincides with the center axis of the array, and the deviation is controlled within ±0.5mm.

[0083] In operation S602, the parallel acquisition function of the capacitive sensing array is applied to synchronously obtain the capacitance values of the mutual capacitances formed by the excitation-detection electrodes.

[0084] The capacitive sensing array can achieve synchronous data acquisition of multiple signal acquisition channels.

[0085] In operation S603, signal amplification and filtering conditioning are performed, and the conditioned digital signal is transmitted to the computer.

[0086] The capacitance value measured between the excitation electrode and the detection electrode is converted into a voltage signal on the detection electrode through the data calculation module. At the same time, the collected voltage signal is amplified, filtered and other conditioned, and transmitted to the computer through the USB interface for functional testing and performance verification.

[0087] In operation S604, the SVR or deep learning algorithm is run to process the conditioned digital signal, and the height value of the plasma or serum liquid level is output.

[0088] Data is obtained from the data transmission and processing module through serial communication, and the computer can be implemented using different programming languages and software platforms. For example, the support vector machine regression algorithm (SVR) or deep learning algorithm is used to calculate the heights of the serum volume and plasma volume in the blood collection tube.

[0089] Figure 7 Schematically shows a schematic diagram of the liquid level height prediction result of the liquid volume detection system based on the capacitive sensing array according to an embodiment of the present disclosure.

[0090] As Figure 7 shown, taking the detection of serum in the blood collection tube as an example, the liquid volume detection system based on the capacitive sensing array is experimentally verified. Through experimental verification, it can be found that the actual value of the serum in the blood collection tube basically coincides with the height prediction value of the liquid volume detection system based on the capacitive sensing array, effectively proving the measurement accuracy and reliability of the liquid volume detection system based on the capacitive sensing array. The capacitance data collected by the capacitive sensing module can accurately predict the liquid volume information in the blood collection tube after being processed by a preset algorithm. The measurement error of the system for the liquid level height is stably and accurately controlled within ±1 mm, and the fitting degree between the actual liquid level height and the predicted height is extremely excellent, further verifying the effectiveness and practicality of the liquid volume detection system based on the capacitive sensing array.

[0091] The above describes the embodiments of the present disclosure. However, these embodiments are only for illustrative purposes and not for limiting the scope of the present disclosure. Although the embodiments are described separately above, this does not mean that the measures in each embodiment cannot be used advantageously in combination. Without departing from the scope of the present disclosure, those skilled in the art can make various substitutions and modifications, and these substitutions and modifications should all fall within the scope of the present disclosure.

Claims

1. A liquid volume detection system based on a capacitance sensing array, characterized in that, The liquid volume detection system includes: a capacitance sensor array, a support housing, a control module, and a data calculation module; The capacitance sensor array is disposed inside the support housing; The support housing is used to support the capacitance sensor array, so that the capacitance sensor array closely adheres to the outer surface of the tubular container; a solution with a liquid volume to be detected is contained in the tubular container; The control module is connected to the capacitance sensor array; the control module is configured to control each of a plurality of excitation electrodes included in the capacitance sensor array to send an excitation signal to a plurality of detection electrodes included in the capacitance sensor array based on a mutual capacitance measurement method; The capacitance sensor array is configured to output capacitance values between the excitation electrode and the corresponding detection electrode under the action of the excitation signal, and obtain a plurality of capacitance values; The data calculation module is configured to calculate the height of the liquid with the liquid volume to be detected in the tubular container according to the plurality of capacitance values.

2. The liquid volume detection system based on a capacitive sensing array according to claim 1, wherein The capacitance sensor array includes two sensor array units with the same structure; The two sensor array units are oppositely arranged; Each of the sensor array units includes a plurality of electrode units; When the capacitance sensor array closely adheres to the outer surface of the tubular container, the plurality of electrode units are uniformly distributed along the axial direction of the tubular container.

3. The liquid volume detection system based on a capacitance sensing array according to claim 2, wherein Each of the electrode units includes a capacitance sensing electrode and a lead electrode; A wire is disposed in a serpentine shape between the capacitance sensing electrode and the lead electrode; The capacitance sensing electrode is closely adhered to the inner surface of the support housing under the support of the support housing; The lead electrodes are respectively connected to the control module and the data calculation module; The lead electrode is configured to be connected to a DC excitation voltage source or the data calculation module under the control of the control module; Wherein, when the lead electrode is connected to the DC excitation voltage source, the capacitance sensing electrode connected to the lead electrode is an excitation electrode; when the lead electrode is connected to the data calculation module, the capacitance sensing electrode connected to the lead electrode is a detection electrode.

4. The liquid volume detection system based on a capacitance sensing array according to claim 3, characterized in that, The liquid volume detection system further includes a wire fixator; One end of the wire fixator is fixed on the outer surface of the support housing; The other end of the wire fixator is provided with a wire fixing groove; the connection wires between the lead electrode and the control module and between the lead electrode and the data calculation module are fixed in the wire fixing groove.

5. The liquid volume detection system based on a capacitive sensing array according to claim 3, wherein When the lead electrode is not connected to the DC excitation voltage source and is not connected to the data calculation module, the lead electrode is connected to the ground under the control of the control module.

6. The liquid volume detection system based on a capacitance sensing array according to claim 1, characterized in that, The support housing sequentially includes an elastic support body and a metal shielding shell from the inside to the outside; A first groove is provided inside the metal shielding shell; the first groove is a cylindrical structure; The elastic support body is disposed in the first groove; the outer surface of the elastic support body is closely attached to the surface of the first groove; The capacitance sensor array is disposed inside the elastic support body; the capacitance sensor array is closely adhered to the outer surface of the tubular container under the support of the elastic support body.

7. The liquid volume detection system based on a capacitance sensing array according to claim 6, characterized in that, A second groove is provided in the elastic support body; the second groove is a cylindrical structure; The curvature of the second groove is consistent with the curvature of the outer surface of the tubular container; When the tubular container is placed in the second groove, the axial direction of the tubular container is consistent with the axial direction of the second groove, and the length of the tubular container is less than the length of the second groove.

8. The liquid volume detection system based on a capacitance sensing array according to claim 1, characterized in that, The data calculation module includes a data acquisition unit and a calculation unit; The data acquisition unit is used to receive a plurality of capacitance values output by the capacitance sensor array; The calculation unit is used to calculate the height of the liquid to be detected in the tubular container according to the plurality of capacitance values.

9. The liquid volume detection system based on a capacitance sensing array according to claim 3, characterized in that, The sensor array unit includes: A flexible base layer; A metal thin film layer, including a plurality of electrode units formed on the flexible base layer; An encapsulation layer, on the flexible base layer, covering the metal thin film layer.

10. The liquid volume detection system based on a capacitance sensing array according to claim 3, characterized in that, The control module includes a channel switching unit and a controller; One end of the channel switching unit is connected to the lead electrode, and the other end is connected to the DC excitation voltage source or the data calculation module; The controller is used to control the channel switching unit so that the lead electrode is connected to the DC excitation voltage source or the data calculation module.

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