Capacitance detection device and method

Abstract

By summarizing the invention, the equipment is provided. The apparatus comprises: a dispensing member configured to draw and dispense a liquid wherein the dispensing member is movable relative to a liquid sample; and a capacitance sensing component coupled to the distribution component and configured to detect a plurality of operating states of the distribution component, where each of the plurality of operating states corresponds to a respective capacitance value of the plurality of capacitance values; wherein the capacitance sensing component has a capacitance sensing range, and the capacitance sensing range is a predefined working range of the capacitance sensing component; and a capacitance of at least a portion of the device is adapted to the capacitance sensing range such that each of the plurality of capacitance values is within the capacitance sensing range.

Description

Technical Field

[0001] The following description relates to apparatus and methods for detecting an operational state of a dispensing component configured to draw and dispense liquids. Background Art

[0002] In the case of processing biological samples for analysis, liquid aspiration and liquid dispensing are common steps, wherein the liquid can be the biological sample itself and / or reagents, for example. These steps are performed by a dispensing component (e.g., a pipette with a pipette tip) configured to extract and dispense liquids.

[0003] Nowadays, sample handling and therefore liquid aspiration / dispensing is performed automatically. Therefore, it is necessary to detect the liquid level to guide the movement of the dispensing part towards and away from the liquid. Conventionally, this detection is performed by a capacitive sensing part that uses capacitance as an indication of whether the tip of the dispensing part is outside or inside the liquid.

[0004] In particular, only binary information is provided about the state of the dispensing component, ie in air or in liquid.Besides the coarseness of the detection, another disadvantage of conventional capacitive sensing is its susceptibility to errors, since it ignores other factors that may affect the capacitance value. Summary of the invention

[0005] It is an object of the present invention to provide reliable and accurate capacitive sensing for liquid aspiration / dispensing.

[0006] The achievement of this object according to the invention is set forth in the independent claim. Further developments of the invention are subject matter of the dependent claims.

[0007] According to one aspect, a device is provided. The device comprises:

[0008] a dispensing member configured to draw and dispense the liquid, wherein the dispensing member is movable relative to the liquid sample; and

[0009] a capacitive sensing component coupled to the dispensing component and configured to detect a plurality of operating states of the dispensing component, wherein each operating state of the plurality of operating states corresponds to a respective capacitance value of the plurality of capacitance values;

[0010] in:

[0011] The capacitive sensing component has a capacitive sensing range, wherein the capacitive sensing range is the capacitive sensing

[0012] The predefined working range of the measured component; and

[0013] The capacitance of at least a portion of the device is adapted to the capacitance sensing range such that a plurality of capacitance values

[0014] Each capacitance value in is within the capacitance sensing range.

[0015] The dispensing part is capable of extracting liquid, i.e. transferring a volume of liquid from the outside of the dispensing part to the inside of the dispensing part, and dispensing liquid, i.e. transferring a volume of liquid from the inside of the dispensing part to the outside of the dispensing part. In the following, the expression "transferring liquid" used in conjunction with the dispensing part will mean both "extracting liquid" and "dispensing liquid".

[0016] Therefore, the dispensing component can also hold a certain volume of liquid, for example after extracting the liquid or before dispensing the liquid. The dispensing component can have a given maximum capacity, that is, it can hold up to a given volume of liquid. In some examples, the volume of liquid that can be extracted by the dispensing component can be variably set according to a predefined volume range for a given dispensing component (for example, a specific model for a specific manufacturer). Therefore, the volume to be extracted can be modified within the constraints of the dispensing component.

[0017] In particular, the dispensing component can be configured to transfer a liquid to / from a liquid sample, which is, for example, held in a liquid sample container (or "sample container") such as a tube. In other words, the dispensing component can transfer a sub-volume of liquid to / from the liquid sample, wherein the sub-volume can be a portion of the total volume of the liquid sample. Exemplarily, the liquid sample can be a sample contained in a sample container processed by an automated laboratory system (ALS). The liquid sample can include a biological sample (e.g., blood, urine) and / or a reagent and / or any other type of liquid used in the context of sample analysis.

[0018] The dispensing member is movable relative to the liquid sample, and thus the dispensing member can be movable relative to the sample container containing the liquid sample. For example, the dispensing member can be moved toward the liquid sample before transferring the liquid, and can be moved away from the liquid sample after the liquid transfer.

[0019] The device may include a mobile device for moving the distribution component. The movement of the distribution component may occur along at least one axis (e.g., a vertical axis), wherein the vertical axis is parallel to the direction of the earth's gravity. For example, the mobile device may move the distribution component downward to contact the liquid sample, and may move the distribution component upward to remove it from the liquid sample. In some examples, the movement of the distribution component may be a translation along an axis (e.g., a vertical axis). In other examples, the movement may be a synthesis of translations along two or three axes (e.g., the x-axis, y-axis, and z-axis of a Cartesian coordinate system). Alternatively, the movement may include rotations along one, two, or three axes. The mobile device of the device may include a robot arm with one or more degrees of freedom.

[0020] Exemplarily, the dispensing part can include a pipette and a pipette tip, and the liquid can be kept in the pipette tip. At least a portion of the dispensing part can be made of a conductive material, for example, the pipette can be made of a conductive material (such as a metal or a conductive polymer) at least in part. In addition, the pipette tip can be conductive, for example, made of a conductive polymer. Therefore, the dispensing part can be conductive, and in particular, the dispensing part can include a conductive pipette and a conductive pipette tip. The pipette can be configured to hold the pipette tip, wherein the pipette tip can be releasably mounted to the pipette. The pipette can be configured to perform the action of liquid transfer, for example, it can include a mechanical element for suction / release of liquid. The pipette can also include a volume setter, by means of which the extraction volume can be set.

[0021] The capacitive sensing component is a sensor configured to detect a plurality of operating states of the dispensing component. In particular, the capacitive sensing component as a sensor uses the physical quantity capacitance as a "proxy variable" for the operating state of the dispensing component.

[0022] The capacitance value is a numerical value that quantifies the capacitance. In one example, the capacitance measured by the capacitive sensing component can be the mutual capacitance between the dispensing component (particularly the conductive pipette) and a conductive element located below the liquid sample, particularly below the sample container, which can be referred to as a "lower conductive element". The lower conductive element can be grounded, or may not be grounded.

[0023] In another example, for example, if the dispensing component is non-conductive, the electrical conductor can be fixed to the dispensing component, and the capacitance can be the mutual capacitance between the electrical conductor and the lower conductive element. Alternatively, two electrical conductors can be fixed to the dispensing component, and the capacitance can be the mutual capacitance between the two electrical conductors. One or both electrical conductors can be fixed to the dispensing component so that the capacitance value measured by the capacitive sensing component identifies the corresponding operating state of the dispensing component. For example, the (one or more) electrical conductors and the dispensing component can form a substantially rigid body so that, for example, movement of the dispensing component requires the same movement of the electrical conductor.

[0024] In any case, the device comprises a sensitive element, the capacitance of which (relative to the lower conductive element) changes when the operating state of the dispensing part changes, wherein the sensitive element can be the dispensing part itself (in particular a pipette) or an electrical conductor attached to the dispensing part.

[0025] The capacitive sensing component can measure the capacitance of the sensitive element by applying an excitation voltage to the sensitive element. Therefore, the capacitive sensing component can be electrically coupled to the sensitive element, in particular the distribution component. In addition, in some examples, the capacitive sensing component can be electrically coupled to the lower conductive element.

[0026] Exemplarily, the capacitive sensing component may include: a measuring element configured to measure the capacitance of a sensitive element, and a processing element configured to use one or more capacitance values ​​to identify multiple operating states. The sensitive element may be electrically connected to the measuring element (e.g., by means of one or more cables), and the measuring element may communicate data with the processing element (e.g., by means of a bus). The measuring element may include an analog-to-digital converter—ADC (particularly a capacitance-to-digital converter—CDC) and an excitation signal source, and the processing element may include a computing device including a processor and a memory.

[0027] The operational state of the dispensing part indicates the condition in which the dispensing part may find itself when operating for the purpose of transferring liquid, wherein the condition is determined by factors internal or external to the dispensing part.

[0028] Factors inherent to the dispensing component may be characteristics of the dispensing component. For example, the characteristics of the dispensing component may be the presence of a pipette tip, in particular the absence of a pipette tip (e.g., in an error situation), the presence of an incorrectly installed pipette tip (e.g., in an error situation), and the presence of a correctly installed pipette tip. Another exemplary characteristic of the dispensing component may be its movement speed.

[0029] Factors extrinsic to the dispensing component may be characteristics of the dispensing component's environment, i.e., characteristics of the physical space that the dispensing component is contained in. Characteristics of the dispensing component's environment may include environmental parameters (e.g., temperature, humidity), the presence of one or more other entities within a predetermined range from the dispensing component, the distance between the other entity / entities and the dispensing component, and / or characteristics of the other entity / entities.

[0030] The environment may include entities included in the device and entities that are not part of the device. For example, an entity that is not part of the device may be a liquid sample or a sample container containing a liquid sample, while an entity that is part of the device may be a holding tool (e.g., a clamp) for holding a sample container, a cover for a barcode reader of the device, or a door of the device, wherein a door is a plate that can be opened or closed and is configured to cover / enclose a portion of the device.

[0031] Each of the characteristics of the dispensing component itself and the characteristics of the environment surrounding the dispensing component can be considered to characterize an operating state of the dispensing component. In other words, the state of a factor can define an operating state of the dispensing component, where the state can be a quality (e.g., door closed or tip not present) or a value (e.g., distance value or temperature value). Because the state of the factor defining the operating state spans a range of possibilities and because there are multiple factors, the dispensing component has multiple operating states.

[0032] For example, the operating state can be a position state or a configuration state, wherein the position state refers to a specific position of the dispensing component relative to another entity (for example, the dispensing component is in contact with the liquid sample), and the configuration state refers to a specific configuration of the dispensing component (for example, the dispensing component has an improperly installed pipette tip).

[0033] The capacitance of the sensitive element is affected by multiple factors that determine multiple operating states. Accordingly, each operating state is characterized by at least one corresponding capacitance value. Therefore, each operating state in the multiple operating states can correspond to at least one corresponding capacitance value in the multiple capacitance values. In other words, each operating state in the multiple operating states can correspond to a corresponding set of capacitance values ​​in the multiple sets of capacitance values. Typically, a set can include one or more elements.

[0034] The capacitive sensing component (particularly the processing element) is configured such that a particular operating state can be associated with at least one capacitance value. In some cases, the operating state can correspond to one capacitance value, which means that the capacitive sensing component can detect the operating state based on one capacitance value. In other cases, the operating state can correspond to a range of capacitance values, i.e., to more than one capacitance value, which means that the capacitive sensing component can detect the operating state based on a range of capacitance values.

[0035] Each capacitance value in a range of capacitance values ​​can be measured by changing the state of a factor defining the operating state in question. For example, an operating state in which a dispensing component contacts a liquid sample (e.g., crosses a meniscus) can be detected via step detection (i.e., by identifying a sudden change in capacitance).

[0036] In examples like the meniscus crossing, detection of the operating state may be achieved based solely on measured capacitance values. In other words, detection may be derived from inherent characteristics of a range of capacitance values, particularly their relationship to one another. In other examples, detection may be achieved by evaluating measured capacitance values ​​against one or more sets of calibration data.

[0037] A set of calibration data may include one or more capacitance values. Exemplarily, calibration of the capacitance sensing component may include systematically measuring multiple capacitance values ​​under different known conditions. In other words, the factors determining the operating state may be changed to cover the operating range of the device. Thus, multiple sets of calibration data may be generated, wherein each set of calibration data is associated with a specific state of a factor. For example, multiple sets of calibration data may be stored in a memory of a processing element.

[0038] Exemplarily, each set of calibration data may include a plurality of value pairs, each value pair including a first value indicating the position of the dispensing component along the vertical axis and a second value indicating the corresponding capacitance. The plurality of value pairs may be referred to as a "calibration curve". A calibration curve may be created for each combination of states of factors related to the operation of the device.

[0039] It should be noted that multiple factors or at least a subset of factors that determine the operating state usually coexist, which means that the dispensing component is usually in a superposition of operating states. For example, the dispensing component may not have a tip, be within a certain distance from the liquid sample, and be in an environment with a certain humidity. Therefore, a set of calibration data may also be generally associated with a superposition of operating states, i.e., associated with a specific state of multiple factors (or a subset thereof).

[0040] Evaluation of the measured capacitance values ​​for one or more sets of calibration data can be used to "disentangling" a given superimposed operating state from other superimposed operating states. Exemplarily, there may be one superimposed operating state that is unknown, while the other (one or more) superimposed operating states may be known (e.g., may be directly observed by a user or detected by another instrument - e.g., the humidity of the environment may be measured by a hygrometer, the presence of a pipette tip may be detected by an optical sensor). The unknown superimposed operating state may be an operating state detected by the capacitive sensing component. Thus, a particular operating state may be identified from the superposition of operating states.

[0041] Thus, in a particular example, the capacitive sensing component can be configured to receive one or more inputs and also detect multiple operating states (each of the operating states) based on the one or more inputs. The one or more inputs can be received from, for example, a computing device of a laboratory automation system and / or from a user.

[0042] Exemplarily, each input may indicate a state of a factor, such as an absent tip or a humidity value. Thus, one or more inputs may specify one or more known overlay operating states (ie, those that are not the object of detection).

[0043] The one or more inputs may identify at least two sets of calibration data, and the capacitive sensing component (particularly the processing element) may access the at least two sets of calibration data. The at least two sets of calibration data may be associated with at least two candidate operating states of the unknown operating state, respectively. In particular, the candidate operating states may be defined by respective different states of the same factor.

[0044] The capacitive sensing component (particularly the processing element) can detect the actual operating state by comparing at least one measured capacitance value with at least two sets of calibration data and determining that a given operating state is a candidate operating state associated with a set of calibration data including at least one measured capacitance value. If the set of calibration data is a calibration curve, in some examples, one or more inputs may include at least one value of a position along a vertical axis, i.e., a state indicating a position factor. In this case, the capacitive sensing component can determine that a given operating state is a candidate operating state associated with the set of calibration data, which includes at least one measured capacitance value associated with at least one value of a position along a vertical axis.

[0045] In the illustrative example, the capacitive sensing component can measure a capacitance value C1. It is not known whether the pipette tip is properly mounted on the dispensing component, and all other factors (e.g., including the position z along the vertical axis) A The state of the factor “pipette tip” is known. There may be three calibration curves corresponding to the three different states of the factor “pipette tip”, namely “pipette tip not present”, “pipette tip not properly installed” and “pipette tip properly installed”. The capacitive sensing component may check the position z in the three calibration curves. A Capacitance value. A , the operating state associated with the calibration curve of C1) is the operating state of the allocation component.

[0046] In a specific example, the plurality of operating states may include a plurality of position operating states, ie, a plurality of positions of the dispensing component.

[0047] Since the dispensing part is an extended object, the position of the dispensing part can be exemplarily the position of the lower end of the dispensing part, that is, the position of the part of the dispensing part that is configured to contact the liquid sample (first) when transferring the liquid. For example, the lower end can be the head of a pipette tip.

[0048] Specifically, the plurality of positions may be along a vertical axis relative to the meniscus of the liquid sample (i.e., relative to the interface liquid / air). The vertical axis may be perpendicular to the meniscus. As discussed above, the dispensing component may move only along the vertical axis, or may move with more degrees of freedom. In any case, the position along the vertical axis may be obtained by projecting the dispensing component (e.g., its lower end) onto the vertical axis.

[0049] The plurality of positions may include a first position in which the distance between the dispensing component and the meniscus is greater than a threshold value, wherein the threshold value is between about 1 mm and about 7 mm, and a second position in which the dispensing component is in contact with the liquid sample. In particular, at the second position, the dispensing component (e.g., a pipette tip) may be at or below the meniscus. In other words, the dispensing component may pass through the meniscus. The threshold value may more particularly be between about 1 mm and about 5 mm, and even more particularly between about 1 mm and about 3 mm.

[0050] The position of the meniscus on the vertical axis may be taken as the origin, such that points above the origin have positive coordinates and points below the origin have negative coordinates. Accordingly, the distance may be a positive distance or a negative distance. In the second position, the dispensing member may have a substantially zero distance (e.g., less than 10°) relative to the meniscus. -8 mm, or more particularly less than 10 -10 mm, or more particularly equal to or less than 10 -12 The absolute value of the negative distance may be less than about 1 mm, or more particularly less than about 0.5 mm, or even more particularly less than about 0.1 mm.

[0051] The ability to detect the first position and the second position improves the automatic transfer of the liquid. Exemplarily, the capacitive sensing component can be configured to send the detected position to the controller of the mobile device, which in turn can adjust the movement accordingly. For example, when the dispensing component is in the first position, the speed can be reduced because the dispensing component is approaching the liquid sample. When the dispensing component is in the second position, the movement can be stopped because the liquid sample has been reached.

[0052] Optionally, the plurality of positions may further include a third position where the distance between the dispensing member and the meniscus is greater than about 0 mm and less than a threshold value. At the third position, the speed may be further reduced.

[0053] In other examples, the plurality of operating states may alternatively or additionally include one or more of the following:

[0054] - an open clamp state, in which the dispensing member transfers liquid to / from a liquid sample in a container not held by the clamp (i.e., a situation in which the clamp is not properly closed);

[0055] - a closed clamp state, in which the dispensing member transfers liquid to / from a liquid sample in a container held by the clamp;

[0056] a tube position state, in which the dispensing member is within a predetermined distance from a sample container containing a liquid sample (eg from the edge of the container);

[0057] - a tube present state, in which a sample container containing a liquid sample is detected in the environment of the dispensing component (e.g. within a predetermined radius);

[0058] a tubeless state, in which no sample container containing a liquid sample is detected in the environment of the dispensing component (eg within a predetermined radius);

[0059] - a correct tip state, in which the pipette tip is correctly mounted in the dispensing part;

[0060] - an incorrect tip state, in which the pipette tip is incorrectly mounted in the dispensing part (eg, mounted tilted);

[0061] a tipless state, in which no pipette is mounted in the dispensing part (ie on the pipette);

[0062] - a plurality of opening states for a corresponding plurality of elements, the plurality of elements comprising a door of the device, a cover of a barcode reader, a splash protection cover, wherein in each opening state a given element is detected as open (or absent) in the environment of the dispensing component;

[0063] - a plurality of closing states for a respective plurality of elements, the plurality of elements comprising a door of the device, a cover of a barcode reader, a splash protection cover, wherein in each closing state a given element is detected as closed in the environment of the dispensing component;

[0064] a tube marking mechanism present state, in which a component configured to transfer a tube label on a tube is detected in the environment of the dispensed component (e.g., within a predetermined radius);

[0065] - a double bottom pipe state, in which a pipe with a double bottom is detected in the environment of the dispensing component (e.g. within a predetermined radius);

[0066] a room temperature state, in which the liquid sample is at room temperature, wherein the room temperature may correspond to the temperature of the environment and may be, for example, between 15° C. and 25° C.;

[0067] - A refrigerated temperature state, in which the liquid sample is at a refrigerated temperature, for example between 0°C and 4°C.

[0068] When the tube is conductive, the tube position state, tube presence state and tube absence state can also be detected in the case of an empty tube.

[0069] In general, by measuring absolute capacitance values, the capacitive sensing component can be used to detect a variety of operating states, not just binary information of whether the dispensing component is in air or in liquid. In particular, detection of any of the above states can be used to ensure that no errors occur during operation of the device.

[0070] A clamp that is not properly closed may not be able to securely hold the sample container (e.g., the sample container may tip over), which may hinder the operation of the dispensing component and / or result in loss or contamination of the liquid sample. The absence or incorrect installation of a pipette tip may prevent the dispensing component from transferring liquid. The presence of an opening element such as a cover may compromise the safety of the operation and, for example, result in cross-contamination. The presence of a tube with a double bottom may confirm that the correct sample / sample container is being processed or indicate that the wrong sample / sample container is being processed, depending on the expected type of tube bottom. Detection of a liquid sample at room temperature may indicate that the liquid sample is not properly stored (e.g., a faulty refrigeration device or incorrect handling of the sample container) and, for example, may have to be discarded. The absence of a component configured to mark a tube within a predetermined radius may indicate an error in operation.

[0071] A capacitive sensing component (particularly a measuring element) has a capacitive sensing range, i.e., a range of values ​​of capacitance values ​​that the capacitive sensing component can correctly measure. In other words, the capacitive sensing range is an operating range, because the capacitive sensing component only works correctly within this range, i.e., it can only accurately measure capacitance values ​​that fall within the capacitive sensing range. If the capacitive sensing range is [C a , C b ] and the capacitance makes its measured value C m In this range, C m ∈[C a , C b ], the capacitive sensing component will output C m As measured value. However, if C m <C a or C m >C b , the measured values ​​are saturated to C a or C b , that is, the capacitance sensing component outputs an incorrectly represented capacitance value.

[0072] The capacitive sensing range is a predefined range that is predetermined for a given capacitive sensing component based on its manufacture. Thus, the capacitive sensing range is set by the manufacturer of the capacitive sensing component (particularly the measuring element) and is fixed.

[0073] In general, any measured capacitance value C m The "true" value of the capacitance of a given object, C trueSpecifically, the capacitance value measured by the capacitive sensing component (especially by the measuring element) does not correspond to the true value of its capacitance. The capacitive sensing component may introduce systematic errors such as offset errors E, making the measured capacitance value C m =C true +E.

[0074] More specifically, since the sensitive element is included in the device, the capacitance measured by the capacitive sensing component always includes a component due to the parasitic capacitance of the device as a whole. Therefore, each capacitance value can be regarded as consisting of a state-related capacitance value and a parasitic capacitance value, in particular, as the sum of the state-related capacitance value and the parasitic capacitance value. The parasitic capacitance value is a value that is fixed for a given device (in particular for a given material and structure of the device). The parasitic capacitance value is included in the systematic error of the capacitive sensing component. The state-related capacitance value depends on the operating state of the assigned component and changes if the factor is modified.

[0075] The capacitance of at least a portion of the device is adapted to the capacitance sensing range, so that each of the plurality of capacitance values ​​is within the capacitance sensing range. In other words, the device is adapted to the characteristics of its capacitance sensing component, so that the capacitance sensing component can be used to detect a plurality of operating states of the dispensing component. The adaptation takes place during the assembly and / or manufacturing phase of the device, before it is used for the automatic transfer of liquids and also before calibration. Further modifications of the device can optionally be performed on an already assembled device.

[0076] Due to the adaptation, it is ensured that capacitance values ​​corresponding to different operating states can be distinguished, in particular there is no saturation in the measurement of the capacitance by the capacitive sensing component. Thus, reliable capacitance sensing is provided.

[0077] In particular, the capacitance of at least a portion of the device can be adapted to the capacitance sensing range because the systematic errors (e.g., parasitic capacitance values) are adapted. Thus, the presence of systematic errors can be exploited to bring the capacitance value within the desired range. For a given operating state, the capacitance C measured by the capacitance sensing component of the device that is not adapted to any portion of the capacitance sensing range is NA It is C NA =C true +E NA , and can be In contrast, the capacitance C measured by the same capacitive sensing component but with a device adapted to at least a portion of the capacitive sensing range A Change to C A =C true +E A , and C A ∈[C a , C b ].

[0078] Exemplarily, the adaptation may involve calculating or measuring the capacitance of the sensitive element in a first state, where the capacitance is maximized to obtain a maximum capacitance value, and in a second state, where the capacitance is minimized to obtain a minimum capacitance value. The device may then be adapted such that the maximum capacitance value is equal to or less than the upper limit C of the capacitance sensing range. b , while ensuring that the minimum capacitance value remains at the lower limit of the capacitance sensing range C a The first state may be a state in which all contributions to the parasitic capacitance value are taken into account (e.g., by having all elements that contribute to the parasitic capacitance value present (e.g., installed or modeled) in the device and / or in a configuration that maximizes the capacitance value (e.g., the dispensing component is inside the liquid). The second state may be a state in which all positive contributions to the parasitic capacitance value are removed or minimized.

[0079] In some examples, since the focus is on modifying the parasitic capacitance value of the device, the adaptation may involve calculating or measuring only the parasitic capacitance value instead of the total capacitance of the sensitive element.The same considerations regarding the first state and the second state apply mutatis mutandis.

[0080] Exemplarily, the capacitance may be adapted to the capacitance sensing range such that each of the plurality of capacitance values ​​is within a sub-range of the capacitance sensing range. For example, the sub-range may have the same middle value as the capacitance sensing range and a width W=C that is 5%, 10%, or 20% smaller. b -C a In another example, the sub-range may be [C a , C s ], where C s =C b -0.1W, or C s =C b -0.3W, or C s =C b -0.5W.

[0081] The device together with the liquid sample and the sample container can be considered to form an electrical circuit, with different components representing passive elements such as resistors and capacitors in addition to the excitation voltage source (e.g. of the measuring element), which is an active element. "At least a part of the device" (whose capacitance is adapted) refers to at least one component of the device, which at least one component is connected to other components, e.g. to become part of an electrical circuit.

[0082] The capacitance of at least a part of the device affects the capacitance of the entire device, in particular the parasitic capacitance value. Therefore, the expression "the capacitance of at least a part of the device is adapted to the capacitance sensing range" is intended to indicate that there is a purposeful tuning of the capacitance of at least a part of the device based on the capacitance sensing range, which translates into an overall tuning of the capacitance of the device.

[0083] At least a portion of a device whose capacitance is adapted to a capacitance sensing range may also be referred to as an "adaptation component", although it may include multiple components. An adaptation component may be a component that is included in a device solely for the purpose of adapting the device to the operation of its capacitance sensing component (i.e., without any other function). Alternatively, an adaptation component may be a component that fulfills one or more roles in a device and whose capacitance is then adapted to a capacitance sensing range.

[0084] Adaptation of the capacitance may be achieved by designing (eg via simulation) an adaptation component, for example according to any one or more of the following: material(s), shape, electrical properties, internal structure. Further details on adaptation as a process are discussed below.

[0085] More generally, not only the capacitance, but also the overall complex impedance of the device may be adapted, ie the combination of resistance, capacitance and inductance. In some cases, resistance and capacitance may be adapted, while inductance may not be adapted.

[0086] In a specific example, the adapting component may be (at least a portion of) the connecting component. Specifically, the device may further include: a frame at a reference potential and a connecting component that mechanically couples the dispensing component to the frame, wherein the connecting component includes a body. At least a portion of the device having a capacitance adapted to the capacitive sensing range may include (at least a portion of) the connecting component or consist of (at least a portion of) the connecting component.

[0087] The frame can be a structure that supports the distribution component, and the connecting component and the distribution component can be movably linked to the housing of the device, in particular via a moving device of the device. Exemplarily, as discussed above, the distribution component, the connecting component and the frame can form a rigid body, and can be moved relative to the housing as a whole (for example, by a moving device), in particular along the z-axis. The frame can be made of a conductive material. Typically, the potential of the frame can be the potential of the housing of the device. Exemplarily, the reference potential can be the potential of the ground, and optionally, the housing can be electrically connected to the ground via a dedicated path. In another example, the reference potential can be different from the ground potential, and can be, for example, the potential of another object to which the housing is electrically connected. The lower conductive element can also be connected to the housing of the device, and can therefore be at a reference potential.

[0088] When the reference potential is ground potential, the capacitive sensing component may be electrically coupled only to a sensitive element such as a distribution component. When the reference potential is not ground potential, the capacitive sensing component may be electrically coupled to both the sensitive element and the lower conductive element.

[0089] The connecting component mechanically couples the dispensing component to the frame. Mechanical coupling between two items requires that there is a physical link between them, i.e. a continuous (i.e. gapless) path can be traced between any point of the first item and any point of the second item. In this case, the path passes through the connecting component.

[0090] Typically, it may be desirable to electrically separate the conductive dispensing component (particularly the pipette) from the frame so as to have a mutual capacitance between the dispensing component and the lower conductive element. In other words, it may be desirable not to bring the dispensing component to a reference potential. Therefore, the dispensing component may be coupled to the frame via an insulator. However, the insulator may act as a dielectric between the "first plate" (dispensing component) and the "second plate" (frame), thereby generating parasitic capacitance.

[0091] Considering the structural / functional constraints on the device, the size of the insulator may have to be greater than a certain threshold, which may result in a large value of the parasitic capacitance. Therefore, the connecting component may include a body made of a conductive material and a first connecting element coupling the body to the distribution component, wherein the first connecting element is made of a first insulating material. In order to reduce the parasitic capacitance, the size of the first connecting element may be minimized.

[0092] In a specific example, the connecting part may include both a first connecting element and a second connecting element, wherein the first connecting element couples the body to the dispensing part and the second connecting element couples the body to the frame; the first connecting element is made of a first insulating material; and the second connecting element is made of a second insulating material. In this case, the body may be made of a conductive material.

[0093] Advantageously, in this particular example, the connection means comprises two insulators (joining elements) linked by a conductor (body), which is equivalent to having two capacitors in series. Thus, the value of the parasitic capacitance can be (further) reduced.

[0094] The first insulating material and the second insulating material may be the same or may be different. Examples of insulating materials that may be used are: silicone, polystyrene, ceramic, glass, polymer materials. For example, the first insulating material and the second insulating material may be polymers selected based on mechanical stability and processability and dielectric constant.

[0095] For example, the composition of the first insulating material and / or the second insulating material can adapt the capacitance of the connection component to the capacitance sensing range. For example, the dielectric constant of the first insulating material and the dielectric constant of the second insulating material can be between 2.3 and 2.9. Additionally or alternatively, the size of the second connecting element and / or the size of the first connecting element can adapt the capacitance of the connection component to the capacitance sensing range. Additionally or alternatively, the shape of the second connecting element and / or the shape of the first connecting element can adapt the capacitance of the connection component to the capacitance sensing range.

[0096] Exemplarily, the shape and / or size of the body may be such that the capacitance of the connection component is adapted to the capacitance sensing range.For example, the body may include one or more cavities, the presence of which modifies the capacitance of the connection component.

[0097] The connecting member may further comprise a hole configured to receive a corresponding screw, the screw being made of, for example, an insulating material, such as a plastic screw. In some cases, the function of the screw may be to fasten the first connection element and / or the second connection element and to adjust the capacitance. In other cases, the function of the screw may not be fastening, but only to adjust the capacitance.

[0098] In a first example, the body as well as the linking elements may be designed for adaptation. In a second example, only features of the body may be tuned for capacitive adaptation. In a third example, only features of the two linking elements or features of the first linking element may be designed / modified for adaptation. For example, these three examples may be applicable to situations where a device is manufactured from scratch.

[0099] In a fourth example, only the second connection element may be designed for adaptation. In other words, at least a portion of the device whose capacitance is adapted to the capacitive sensing range may include or consist of a second connection element. Exemplarily, the second connection element may have the shape of a cuboid with approximate dimensions of 0.5 cm×0.75 cm×3 cm and may be made of polypropylene. The provision of a second connection element as described is a simple and effective way to modify, for example, a pre-existing device (in particular a pre-existing device that already includes a body and a first connection element) so that it matches the operation of the capacitive sensing component.

[0100] In a specific example, the device may also include a correction circuit including one or more electrical components, wherein at least a portion of the device having a capacitance adapted to the capacitance sensing range includes the correction circuit. In other words, the one or more electrical components are configured to adapt the capacitance of at least a portion of the device to the capacitance sensing range.

[0101] Therefore, the adaptation component may include or consist of a correction circuit. The capacitance of one or more electrical components is selected based on the capacitance sensing range, that is, so that the capacitance value relative to the operating state is within the predefined working range of the capacitance sensing component. In particular, the total capacitance of the correction circuit can modify the parasitic capacitance value of the device in the direction required to make the capacitance value within the capacitance sensing range. Specifically, the correction circuit can be inserted into the device so that its total capacitance is combined in series or in parallel with the existing parasitic capacitance, that is, the parasitic capacitance value is reduced or increased, respectively. Exemplarily, the correction circuit may include or consist of one or more capacitors.

[0102] The device described herein may be used in a method according to the following aspects. The method comprises:

[0103] moving the dispensing member toward the liquid sample;

[0104] detecting, by a capacitive sensing component, when the dispensing component crosses a meniscus of the liquid sample;

[0105] In response to detecting that the dispensing member has crossed the meniscus of the liquid sample:

[0106] extracting an aliquot from the liquid sample by a dispensing member; or

[0107] dispensing the aliquot into the liquid sample by a dispensing component;

[0108] Move the dispensing member away from the liquid sample.

[0109] Exemplarily, the moving device of the device can move the dispensing component downward along the vertical axis toward the liquid sample contained in the sample container. When the dispensing component (e.g., the pipette tip) passes through the meniscus of the liquid sample (i.e., moves from air to liquid), the capacitive sensing component detects the operating state. For example, the capacitive sensing component can collect a series of capacitance values ​​and identify a sudden change in the series, and determine that the dispensing component has passed through the meniscus due to the sudden change.

[0110] In response to detecting that the dispensing member has passed through the meniscus of the liquid sample, a controller of the dispensing member (which may or may not be consistent with a controller of the mobile device) may control the dispensing member to transfer liquid to / from the liquid sample. The dispensing member extracts an aliquot from the liquid sample or dispenses an aliquot into the liquid sample.

[0111] After the liquid transfer is completed, the moving means of the device may move the dispensing member upwards, for example along a vertical axis, away from the liquid sample contained in the sample container.

[0112] Another aspect of the invention relates only to the connection component. As described, the connection component is configured to couple the distribution component to the frame at a reference potential, wherein:

[0113] a dispensing component configured to draw and dispense liquid and coupled to the capacitive sensing component;

[0114] The capacitive sensing component is configured to detect a plurality of operating states of the dispensing component, wherein each operating state of the plurality of operating states corresponds to a respective capacitance value of the plurality of capacitance values;

[0115] The capacitive sensing component has a capacitive sensing range, wherein the capacitive sensing range is a predefined operating range of the capacitive sensing component; and

[0116] The capacitance of the connecting component is adapted to the capacitance sensing range such that each capacitance value of the plurality of capacitance values ​​is within the capacitance sensing range.

[0117] Yet another aspect of the present invention relates to a method for providing an apparatus comprising: a dispensing component configured to draw and dispense a liquid, wherein the dispensing component is movable relative to the liquid sample; and a capacitive sensing component coupled to the dispensing component and configured to detect a plurality of operating states of the dispensing component, wherein each operating state of the plurality of operating states corresponds to a respective capacitance value of a plurality of capacitance values, the method comprising:

[0118] determining a sensing range of the capacitive sensing component; and

[0119] A capacitance of at least a portion of the device is adapted to a capacitance sensing range such that each capacitance value of a plurality of capacitance values ​​is within the capacitance sensing range.

[0120] Determining the sensing range may include retrieving the sensing range from a source (e.g., from a database (manually or automatically) or from a technical documentation file (e.g., by a user). Alternatively, determining the sensing range may include testing the capacitive sensing component to experimentally determine what the operating range of the capacitive sensing component is.

[0121] Adapting the capacitance may include adding one or more components to the device and / or modifying one or more components of the device. In particular, the addition and / or modification may modify the parasitic capacitance of the device so as to shift the capacitance value measured by the capacitance sensing component without adaptation to the capacitance value measured by the capacitance sensing component with adaptation, wherein the latter value is within the capacitance sensing range.

[0122] In the equivalent circuit of the device, the parasitic capacitance can be represented by a first capacitor. Exemplarily, adapting the capacitance of at least a portion of the device can include reducing the parasitic capacitance or increasing the parasitic capacitance. To achieve the former, a component can be added or modified so that it represents a second capacitor in series with the first capacitor in the equivalent circuit. To achieve the latter, a component can be added or modified so that it represents a second capacitor in parallel with the first capacitor in the equivalent circuit. Exemplarily, as explained above, this is achieved by having a second connecting element in addition to the first connecting element.

[0123] In the following, the case of adaptation resulting in a reduction of parasitic capacitance is discussed, however, the same applies mutatis mutandis to other cases.

[0124] For example, in order to reduce the parasitic capacitance by a desired correction value ΔΔC, if the original parasitic capacitance is C1, the following equation can be solved for C2 to obtain the value of the capacitance of the second capacitor:

[0125]

[0126] More specifically, one can consider different, separate contributions to the measured capacitance. As mentioned above, the measured capacitance includes a state-dependent capacitance value and a parasitic capacitance value. The state-dependent capacitance value receives contributions from all objects between the pipette (as a sensitive element) and the lower conductive element. The parasitic capacitance value receives contributions from all objects between the pipette and the frame.

[0127] In detail, the contribution to the state-dependent capacitance value can be the capacitance of the gap between the pipette tip and the liquid level (C gap ), the capacitance of the liquid sample and the sample container together (C tube ) and optionally a capacitance (C ) of a carrier (or "plate") configured to receive a liquid sample container and move the liquid sample container, for example, along a track puck ). Contributions to the parasitic capacitance value can be the capacitance of the mounting (e.g., connecting the component) to the frame (C mount ). Therefore, the measured capacitance value of the non-adapted device can be:

[0128]

[0129] In order to C NA To reduce the value of by a desired amount, such as to bring it within the capacitance sensing range or to move it into a sub-interval of the capacitance sensing range, the connection components of the device may be modified and / or correction circuitry may be inserted so that the measured capacitance value of the adapted device may be:

[0130]

[0131] Among them, C corris the capacitance introduced by adaptation of the device (e.g. by inserting a second connecting element or capacitor). For example, C corr can be the capacitance of the second connecting element. Then, as already mentioned above, the desired correction value is

[0132]

[0133] In determining C mount After ΔΔC, we can target C corr Solve the above equation. This can be done analytically and / or numerically (e.g. using the finite element method (FEM)). In particular, the method may include measuring (or calculating) C mount , set ΔΔC (or set C m A ount , which are equivalent), determine how to achieve ΔΔC and implement the adaptation of the equipment to achieve this. Additional measurements or calculations can also be made and then C A As discussed below, determining how to achieve ΔΔC may include explicitly or implicitly obtaining C corr , for example using analytical or numerical methods, respectively.

[0134] The desired correction value ΔΔC can be obtained by manufacturing constraints and by considering the obtained C A It can be noted that the following situations may occur: C NA ≥C b or C NA <C b In the former case, the desired correction value ΔΔC can be obtained as ΔΔC=C NA -C b +μ, where μ can be approximately C b -0.1W, or about C b -0.3W, or about C b -0.5W. For C NA The measured saturation value is erroneously equal to C b , if μ is not sufficient, the method may include a further iteration of the determination of the desired correction value ΔΔC. Strictly greater than C b The value of C NA Can only be obtained through simulation. NA <C b In the case of b -C NA When the power consumption is less than a predetermined threshold (eg, 0.1 W or 0.3 W), the adaptation may be performed and ΔΔC may be equal to μ.

[0135] In some examples, the step of setting ΔΔC may be performed strictly before the step of determining how to achieve ΔΔC. In other examples, the steps of setting ΔΔC and determining how to achieve ΔΔC may be performed simultaneously with each other, as various options may be tried to see the effect on ΔΔC, and then a particular ΔΔC and its corresponding implementation may be selected.

[0136] Exemplarily, computer-aided design (CAD) can be used to simulate the device to model the device. For example, the software EMS of EMWorks can be used. The model of the device can include at least a sensitive element (e.g., a pipette) and a portion of the device whose capacitance must be adapted, such as a connecting component. The model can include a grid of the device to be optimized, including nodes, wherein the number and distribution of the nodes can depend on the variability of the element (e.g., more nodes in a curved region, fewer nodes in a flat region). The grid nodes are used for calculations in the FEM method.

[0137] Two or more points of the device between which the capacitance should be measured (virtual connection points for measurement) can be selected, the materials used (e.g., their material constants, such as dielectric constant) can be defined, and then different features of the device (e.g., the shape and / or material of the components) can be modified to observe their influence on the capacitance. Typically, there may be mechanical constraints, geometric constraints, and dimensional constraints on the components of the device and their connections, as well as stability requirements to be met. The choice of material may also be important, since too significant discontinuities in the permeability of the material may be undesirable. In addition, if an already existing device is to be adapted (as opposed to creating an adapted device from scratch), additional constraints may be given.

[0138] For example, the modeled device may include a connection component, wherein the characteristics of the body (made of conductive material) and the characteristics of the first connecting element may be fixed. The capacitance may be measured between the sensitive element and the body. The material and dimensions of the second connecting element (which determine C corr ) can be varied to optimize according to the desired ΔΔC. Furthermore, the fastening means (e.g. for connecting the second coupling element to the body and / or the frame) can also be considered variable, as they can be conductive fastening means or insulating fastening means. In this case, C corr It can be obtained implicitly by obtaining the optimal configuration for the second link element.

[0139] If an analytical approach is used, a rough estimate of the capacitance of the second connecting element can be obtained by using the dielectric value of the second insulating material and the dimensions of the second connecting element and by modeling the second connecting element as a parallel plate capacitor. In this case, C can be obtained explicitly corr The value of .

[0140] Once it has been determined, for example with the aid of a calculation model, how the desired ΔΔC is to be achieved, a specific adaptation of the device can be implemented, for example by adding components or modifying already existing components.

[0141] In a specific example, adapting a capacitance of at least a portion of the device to a capacitance sensing range may include:

[0142] coupling the distribution component to a frame of the device by means of a connecting component comprising a body, wherein the frame is at a reference potential;

[0143] The capacitance of the connecting component is adapted to the capacitive sensing range.

[0144] Illustratively, coupling the dispensing component to the frame may include mechanically coupling a connecting component to the dispensing component and mechanically coupling the connecting component to the frame.The above discussion regarding the connecting component also applies to aspects of the method.

[0145] Specifically, adapting the capacitance of the connection component to the capacitance sensing range may include:

[0146] A connecting component is provided, such that the connecting component further comprises a first connecting element and a second connecting element, wherein:

[0147] A first coupling element couples the body to the dispensing member and a second coupling element couples the body to the frame;

[0148] The first coupling element is made of a first insulating material; and

[0149] The second coupling element is made of a second insulating material.

[0150] Additionally or alternatively, adapting the capacitance of the connection component to the capacitance sensing range may comprise selecting a shape of the body such that the capacitance of the connection component is adapted to the capacitance sensing range.

[0151] In a specific example, adapting the capacitance of the connection component to the capacitance sensing range may include providing a second coupling element made of a (second) insulating material in the connection component to couple the block including the body, the first coupling element and the dispensing component to the frame. BRIEF DESCRIPTION OF THE DRAWINGS

[0152] The details of the exemplary embodiments are described below with reference to the exemplary drawings. Other features will be apparent from the description, drawings and claims. However, it should be understood that even if embodiments are described separately, individual features of different embodiments may be combined into other embodiments.

[0153] Figure 1 Some exemplary components of the device are shown.

[0154] Figure 2Some exemplary components of a computer modeling apparatus are shown.

[0155] Figure 3 An exemplary device is shown in operation.

[0156] Figure 4 Shown with Figure 3 The corresponding equivalent circuit.

[0157] Figures 5 to 8 It shows how the measured capacitance is affected by various factors.

[0158] Fig. 9 An exemplary method for providing an adaptation device is shown.

[0159] Fig.10 A comparison between two capacitance curves is shown, one for a non-adapted device and one for an adapted device.

[0160] Fig.11 It is shown how the measured capacitance is affected by the presence of the pipette tip. DETAILED DESCRIPTION

[0161] Hereinafter, a detailed description of the examples will be given with reference to the accompanying drawings. It should be understood that various modifications may be made to the examples. Unless otherwise explicitly stated, elements of one example may be combined and used in other examples to form new examples.

[0162] Figure 1 A device 100 comprising a dispensing component 20, a capacitive sensing component 30 and a connecting component 50 is shown.

[0163] More specifically, the figure shows a portion of a dispensing component 20, namely a pipette 22, a pipette tip 24 (see Figure 3 ) can be releasably mounted on the pipette 22. The dispensing part 20 transfers the liquid to / from the sample container containing the liquid sample and also holds the liquid. The pipette 22 has an elongated shape, in particular a substantially cylindrical shape, wherein the diameter of the cylinder can vary over the length of the pipette 22. The pipette 22 is at least partially made of a conductive material. The pipette 22 may include a locking portion (e.g., a recess or a protrusion) for engaging with a pipette tip 24. The pipette tip 24 has a generally conical shape and includes a hole through which the liquid can pass. The pipette tip 24 is made of plastic or glass.

[0164] The pipette 22 is electrically connected to the capacitive sensing component 30, for example, by means of a cable 35. The capacitive sensing component 30 includes a measuring element and a processing element, wherein the measuring element includes an excitation signal source (e.g., an AC voltage source) and a CDC. The processing element includes at least one memory and at least one processor, as well as software for processing and interpreting the measured capacitance value. The capacitive sensing component has a capacitance sensing range of width W [C a , C b ]. In an illustrative example, the capacitance sensing range may be 8pF to 25pF, where W equals 17pF.

[0165] The capacitive sensing component 30 measures the capacitance between the pipette 22 and a lower conductive element (not shown), which may be a metal plate at a location configured to receive a sample container (e.g., a receiving portion of the device). In one example, the capacitive sensing component 30 may be a two-electrode sensor, in which the pipette 22 is connected to an excitation signal source and the lower conductive element is connected to a CDC input. In another example, the capacitive sensing component 30 may be a single-electrode sensor that applies an excitation signal to the pipette 22 and also reads capacitance from the pipette 22, while the lower conductive element is grounded.

[0166] The dispensing part 20 (specifically, the pipette 22) is connected to the connecting part 50. The connecting part 50 includes a body 52, a first connecting element 54 and a second connecting element 56. The body 52 is made of a conductive material (e.g., aluminum) and can be a substantially solid structure with a cavity. The cavity can include a through hole in at least one direction, which means that the body 52 has at least two opposite holes, such as a circular hole. These two holes can allow the upper part of the pipette 22 to be inserted through them. The cavity can present other holes on the surface of the body 52.

[0167] The body 52 and the pipette 22 are not in direct contact with each other, but are coupled via a first coupling element 54. The first coupling element 54 is made of a first insulating material (e.g., The pipette 22 may be made of a plastic bearing material) and may include two substantially tubular portions separated from each other, wherein each tubular portion is inserted between a portion of the pipette 22 and a corresponding hole in the two opposing holes.

[0168] In particular, the inner diameter of each tubular portion allows the corresponding portion of the pipette 22 to fit (e.g., fit tightly) within the tubular portion. Therefore, if the diameter of the pipette 22 changes, the inner diameter of each tubular portion can change over the length of the tubular portion. In addition, each tubular portion has a portion whose outer diameter corresponds to the diameter of its corresponding hole and a portion whose outer diameter is greater than the diameter of the corresponding hole, so as to fix the pipette 22. In order to further securely fasten the pipette 22, a nut can be used on one side of the upper tubular portion, wherein the pipette 22 itself serves as a bolt.

[0169] The body 52 is also coupled to the frame 40 via a second coupling element 56 (see Figure 2 ), so that the body 52 and the frame 40 are not in direct contact with each other. The second coupling element 56 is made of a second insulating material (e.g., polypropylene) and may substantially have a rectangular cube shape with approximate dimensions of 0.5 cm×0.75 cm×3 cm (thickness×width×length) and a capacitance of about 13 pF. In particular, the thickness may be the interval between the body 52 and the frame 40.

[0170] The second coupling element 56 may include two sets of holes, wherein one set of holes is configured to receive at least one protrusion of the body 52 and the other set of holes is configured to receive at least one fastening element for securing the second coupling element 56 to the frame 40. For example, there may be two holes for receiving two corresponding protrusions of the body 52 and two holes for receiving two fastening elements. The fastening elements may be conductive or insulating.

[0171] like Figure 2 As shown, the frame 40 is a structure that supports the dispensing component 20. The frame is at a reference potential, such as ground potential. The frame is made of a conductive material, and it has a shape determined by functional and structural constraints. For example, the device can be an equalizer module in an automated laboratory system, the equalizer module has a housing, and the frame can be an interface between the dispensing component 20 and the housing. In particular, the frame 40 can connect the connecting component 50 and the dispensing component 20 to the XY worktable and the Z-axis linear actuator.

[0172] In fact, if Figure 3 As shown, the dispensing member 20 together with the connecting member 50 and the frame 40 is movable relative to the sample container 60 containing the liquid sample 65. For example, the dispensing member 20 can be moved downward toward the sample container 60 before extracting or dispensing the liquid, and can be moved upward away from the sample container 60 when the liquid has been extracted or dispensed.

[0173] Figure 3 The device 100 shows a pipette tip 24 mounted to a pipette 22. The pipette tip 24 is shown containing an aliquot and an aerosol above the aliquot, wherein the aerosol is prevented from rising in the pipette shaft by a filter. The sample container 60 is contained in a carrier or tray 70 that can move the sample container 60 along the track of the ALS.

[0174] Figure 4 Shown with Figure 3 It can be seen that the capacitive sensing component 30 is configured to measure the variable capacitance (C gap), the capacitance of the liquid sample and the sample container (C tube ) and the capacitance of the disk plus track (C puck ). Since they are connected in series with each other, the state-dependent capacitance value is given by:

[0175]

[0176] Instead, the circuit branch from the connection point of the capacitive sensing component 30 to the ground frame 40 contributes a parasitic capacitance value

[0177]

[0178] Among them, C fje is the capacitance of the first coupling element 54, C sje is the capacitance of the second coupling element 56, and C par is the total capacitance of the connection component 50.

[0179] Therefore, the total capacitance measured by the capacitive sensing component 30 of the adaptation device 100 is

[0180]

[0181] For a given device 100 and a given sample container 60, the only variable contribution is C gap , which depends on the operating state of the dispensing component 20. Figures 5 to 8 Shows how different factors affect C gap .

[0182] Figure 5 shows the measured capacitance (which includes C gap ) varies with the distance between the pipette tip 24 (the head) and other entities. The “origin position” on the vertical axis corresponds to the idle position of the dispensing component 20. The five specific positions of the pipette tip 24 are Figure 5 The curves are marked with corresponding letters A to E.

[0183] At position A, about 130 mm below the origin position, the pipette tip 24 may encounter a cover for a barcode reader of the device. As used herein, "encounter" means that the pipette tip 24 is at the same vertical level as another entity (e.g., a cover). For example, the upper edge of the cover may be about 130 mm below the origin position, and the cover may be horizontally displaced, for example, about 8 cm relative to the vertical axis along which the dispensing component 20 moves.

[0184] At position B, about 170 mm below the origin position, the pipette tip 24 may encounter the tube, in particular the upper edge of the tube. At position C, about 190 mm below the origin position, the pipette tip 24 may encounter the upper edge of the fixture holding the tube, and at position D, about 205 mm below the origin position, the pipette tip 24 may encounter the lower edge of the fixture. Finally, at position E, the pipette tip 24 may encounter the meniscus of the liquid sample 65.

[0185] Figure 6 shows the measured capacitance (which includes C gap ) varies depending on the characteristics of the environment of the dispensing part 20 (specifically, the relative position between the meniscus and the clamp). Curve (a) shows the case where the meniscus is above the upper edge of the clamp, curve (b) shows the case where the meniscus is between the upper and lower edges of the clamp, and curve (c) shows the case where the meniscus is below the lower edge of the clamp.

[0186] Figure 7 shows the measured capacitance (which includes C gap ) varies depending on the characteristics of the environment of the dispensing component 20, in particular, the presence of an equipment door. The equipment door may have an extension along the vertical axis that covers the distance between the origin position and the bottom of the tube. Curve (a) shows the case where the equipment door is present, while curve (b) shows the case where the equipment door is not present.

[0187] Figure 8 shows the measured capacitance (which includes C gap ) varies depending on the characteristics of the environment of the dispensing part 20, in particular the presence of a cover for the barcode reader. The cover may have an extension along the vertical axis ranging from about 100 mm below the origin position to the bottom of the tube. Curve (a) shows the case where there is no cover, while curve (b) shows the case where there is a cover.

[0188] Figures 5 to 8 The curve shown in is a calibration curve and shows that the absolute value of the capacitance (as opposed to just its relative change) can provide useful information for determining the operating state of the dispensing component 20, including the position relative to the meniscus and the presence / absence / position of other entities, which provides the possibility of checking whether the configuration of the device is correct.

[0189] Although Figures 5 to 8 The values ​​of capacitance shown in have been obtained using a non-adapted device, but the same calibration / detection principles discussed with reference to these figures apply to the adapted device 100.

[0190] The non-adapted device is identical to the device 100 except for the presence of the second coupling element 56. Therefore, the capacitance measured in this case is

[0191]

[0192] It can be seen that there is C NA Saturation situations, such as Figure 6 (curves a and b), Figure 7 and Figure 8 (Curve b). Figures 5 to 8 The capacitance axis has an offset of 17 pF, so that, for example Figures 6 to 8 The actual capacitance value in is between 21 pF and 25.5 pF. In the illustrative example mentioned above, the capacitance sensing range has 25 pF as an upper limit, and therefore, any value above this upper limit is saturated.

[0193] An exemplary method for retrofitting such an existing non-adapted device is described in Fig. 9 The method includes determining a capacitance sensing range of the capacitance sensing component 30 at 920, and adapting the capacitance of at least a portion of the device to the capacitance sensing range 30 at 940, such that each capacitance value of a plurality of capacitance values ​​is within the capacitance sensing range. In particular, the method includes adapting the capacitance of the connection component 50 to the capacitance sensing range 30, such that each capacitance value of a plurality of capacitance values ​​is within the capacitance sensing range.

[0194] This adaptation step involves numerically calculating (using computational FEM) C par (ie, the capacitance of the connecting component 50 in the original, non-adapted configuration, where C par =C fje Then, by simulating an operating state with relatively high capacitance (e.g. when the pipette tip is at the liquid meniscus / inside the liquid sample), C NA To set the desired correction value ΔC.

[0195] The second coupling element 56 can then be introduced in the simulation of the connection part 50, and the parameters (e.g., material and size) of the second coupling element 56 are varied until the desired ΔC is achieved. In the illustrative example, it can be determined that the second coupling element 56 should have a capacitance of about 13 pF, and for this purpose, it should have approximate dimensions of 0.5 cm×0.75 cm×3 cm and be made of polypropylene. The second coupling element 56 according to the parameters determined by the simulation is then obtained (e.g., manufactured) and introduced into the device between the body 52 and the frame 40, thereby producing an adapted device 100.

[0196] Fig.10It shows how the capacitance value shifts when using the adapted device 100 (curve a) relative to when using the non-adapted device 100 (curve b). It is obvious that curve (b) has saturation, i.e., a value above the upper limit of 25 pF, while curve (a) shows no saturation because the higher value of the curve has shifted to about 12 pF. Therefore, the adapted device 100 provides accurate and reliable capacitance sensing.

[0197] Fig.11 The Figures 5 to 8 Another example of a calibration curve similar to the calibration curve of but obtained with an adapted device 100, which shows how the measured capacitance is affected by the presence of a pipette tip. Curve (a) and Fig.10 The curve (a) is the same as that of FIG. 2 , while the curve (b) shows the capacitance value when the pipette tip 24 is not mounted to the pipette 22 .

Claims

1. A device comprising: a dispensing member configured to draw and dispense a liquid, wherein the dispensing member is movable relative to the liquid sample; and a capacitive sensing component coupled to the dispensing component and configured to detect a plurality of operating states of the dispensing component, wherein each operating state of the plurality of operating states corresponds to a respective capacitance value of a plurality of capacitance values; in: The capacitive sensing component has a capacitive sensing range, wherein the capacitive sensing range is a predefined operating range of the capacitive sensing component; and The capacitance of at least a portion of the device is adapted to the capacitance sensing range such that each capacitance value of the plurality of capacitance values ​​is within the capacitance sensing range.

2. The device according to claim 1, wherein: The plurality of operating states comprises a plurality of positions of the dispensing member relative to the meniscus of the liquid sample along a vertical axis, the plurality of positions comprising: a first position in which the distance between the dispensing member and the meniscus is greater than a threshold value, wherein the threshold value is between about 1 mm and about 7 mm, A second position in which the dispensing member is in contact with the liquid sample.

3. The device according to claim 2, wherein: The plurality of locations also includes: A third position, in which the distance between the dispensing member and the meniscus is greater than about 0 mm and less than the threshold value.

4. The device according to any one of claims 1 to 3, further comprising: a frame at reference potential; a connecting member that mechanically couples the dispensing member to the frame, wherein the connecting member includes a body; Therein, the at least part of the device having a capacitance adapted to the capacitance sensing range comprises the connection component.

5. The apparatus according to claim 4, wherein: The connecting part further comprises a first connecting element and a second connecting element, wherein the first connecting element couples the body to the dispensing part and the second connecting element couples the body to the frame; The first connecting element is made of a first insulating material; and The second connecting element is made of a second insulating material.

6. The apparatus according to claim 5, wherein: The composition of the first insulating material and / or the second insulating material is such that the capacitance of the connecting component is adapted to the capacitance sensing range; and / or The size of the first coupling element and / or the size of the second coupling element are such that the capacitance of the connecting component is adapted to the capacitive sensing range.

7. The apparatus according to any one of claims 4 to 6, wherein: The shape of the body is such that the capacitance of the connecting component is adapted to the capacitance sensing range.

8. The apparatus according to any one of the preceding claims, further comprising: A correction circuit, the correction circuit comprising one or more electrical components, wherein the at least a portion of the device having a capacitance adapted to the capacitance sensing range comprises the correction circuit, and wherein the one or more electrical components are configured such that the capacitance of the at least a portion of the device is adapted to the capacitance sensing range.

9. Apparatus according to any one of the preceding claims, wherein: Each capacitance value of the plurality of capacitance values ​​is composed of a state-dependent capacitance value and a parasitic capacitance value; and The capacitance of at least a portion of the device is adapted to the capacitance sensing range because the parasitic capacitance value is adapted.

10. A connection component configured to couple a distribution component to a frame at a reference potential, wherein: The dispensing component is configured to draw and dispense liquid and is coupled to the capacitive sensing component; The capacitive sensing component is configured to detect a plurality of operating states of the dispensing component, wherein each operating state of the plurality of operating states corresponds to a respective capacitance value of a plurality of capacitance values; The capacitive sensing component has a capacitive sensing range, wherein the capacitive sensing range is a predefined operating range of the capacitive sensing component; and The capacitance of the connection component is adapted to the capacitance sensing range, so that each capacitance value of the plurality of capacitance values ​​is within the capacitance sensing range.

11. A method for providing an apparatus according to any one of claims 1 to 9, the method comprising: determining the capacitive sensing range of the capacitive sensing component, wherein the capacitive sensing range is a predefined operating range of the capacitive sensing component; and A capacitance of at least a portion of the device is adapted to the capacitance sensing range such that each capacitance value of the plurality of capacitance values ​​is within the capacitance sensing range.

12. The method according to claim 11, wherein: Adapting the capacitance of at least a portion of the device to the capacitance sensing range comprises: coupling the distribution part to a frame of the device by means of a connection part comprising a body, wherein the frame is at a reference potential; The capacitance of the connecting component is adapted to the capacitance sensing range.

13. The method according to claim 12, wherein: Adapting the capacitance of the connection component to the capacitance sensing range comprises: The connecting component is provided so that the connecting component further comprises a first connecting element and a second connecting element, wherein: The first coupling element couples the body to the dispensing member, and the second coupling element couples the body to the frame; The first connecting element is made of a first insulating material; and The second connecting element is made of a second insulating material.

14. The method according to claim 12 or 13, wherein: Adapting the capacitance of the connection component to the capacitance sensing range further comprises: selecting a shape of the body so that the capacitance of the connection component is adapted to the capacitance sensing range.

15. A method for using the apparatus according to any one of claims 1 to 9, the method comprising: moving the dispensing member toward the liquid sample; detecting, by the capacitive sensing component, when the dispensing component crosses a meniscus of the liquid sample; In response to detecting that the dispensing member has crossed the meniscus of the liquid sample: extracting an aliquot from the liquid sample by the dispensing member; or dispensing the aliquot into the liquid sample by the dispensing component; The dispensing member is moved away from the liquid sample.

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