LU501475B1

LU501475B1 - Method for determining a function for determining a volume of liquid to be dispensed

Info

Publication number: LU501475B1
Application number: LU501475A
Authority: LU
Inventors: Johannes Köppern
Original assignee: Dispendix Gmbh
Priority date: 2022-02-15
Filing date: 2022-02-15
Publication date: 2023-08-16

Abstract

The invention relates to a method for determining a function determining a volume of liquid to be dispensed from a receptacle (2) comprising an inlet opening (3) for inletting a liquid (1) into the receptacle (2) and an outlet opening (4) for dispensing liquid from the receptacle (2) when a pressure is applied on the liquid (1), wherein at least one coefficient of the function is determined by using a first determination process and at least one other coefficient of the function is determined by using a second determination process..

Description

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LU501475

Method for determining a function for determining a volume of liquid to be dispensed

The invention relates to a method for setting a volume of liquid to be dispensed and a control unit executing the method. Additionally, the invention relates to a dispensing device for dispensing liquid, a computer program product, a computer readable data carrier and a data carrier signal.

Liquid handling is a fundamental process in many laboratories. In modern life science laboratories, high- throughput liquid handling is frequently needed for the purpose of efficiency. For liquid dispensing at the micro-, nano-, or even picoliter level, the surface adhesion is a fundamental factor that affects the performance. Basically, liquid-dispensing technologies have to overcome surface adhesion and dispense the droplet from the dispensing tool. When the volume is very small, gravity is not sufficient for dropping viscous samples. À variety of methods have been developed to overcome the problem by generating additional driving forces to dispense the droplet. In general, those methods can be classified into two categories: contact and noncontact dispensing, respectively.

In contact dispensing techniques, such as pipetting, a touch-off is necessary to complete the liquid dispensing. When the liquid attaches to a substrate, a drag-back action is done to overcome the surface tension between liquid and the dispensing tip, without which the liquid will not drop. Contact dispensing is most popular for dispensing samples of small volume from nano- to microliter because of its simplicity, reliability, and low cost. However, reliable dispensing requires an accurate positioning system.

Furthermore, special attention must be paid to hard contact, which may damage the dispenser tip by colliding with the container.

In noncontact dispensing techniques, the liquid is ejected from an orifice instead of using a contact between the liquid and the surface container. It reduces or eliminates some disadvantages of contact dispensing mentioned above. In particular, cross-contamination can be avoided. The most common approaches are based on the inkjet printing technology, thereby using different dispensing means, such as solenoid valves, piezoelectric dispensers, acoustic dispensers, electrostatic devices, etc.

Typically, liquid handling refers to small volume dispensing operations, however, at the micro-, nano- or picoliter level, the number of transferred samples can be huge. Under these conditions, liquid handling by hand can be very time-consuming and, in some cases, impractical.

Consequently, there is a strong demand for automated liquid handling systems. From the prior art, dispensing device are known that comprise a dispensing head by means of which a pressure is applied on a liquid in a receptacle having an outlet opening. Due to the pressure a liquid is dispensed from the receptacle. There exists the need to secure that the dispensed liquid volume corresponds with a predetermined liquid volume independent of several parameters like the receptacle volume and/or the used liquid type. This is in particular important for liquids that are expensive and/or there the available liquid volume is small. The known devices are not capable to ensure that the dispensed liquid volume

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LU501475 corresponds with a predetermined liquid volume when the predetermined liquid volume is low, in particular in the area between nano- to microliters.

The objective of the invention is to provide a function that determines a volume of liquid to be dispensed in an easy and accurate manner.

The objective is solved by a method for determining a function determining a volume of liquid to be dispensed from a receptacle comprising an inlet opening for inletting a liquid into the receptacle and an outlet opening for dispensing liquid from the receptacle when a pressure is applied on the liquid, wherein at least one coefficient of the function is determined by using a first determination process and at least one other coefficient of the function is determined by using a second determination process.

Another objective of the invention is to provide a dispensing device, in which a function that determines a volume of liquid to be dispensed in an easy and accurate manner is provided.

This objective is solved by a dispensing device for dispensing liquid, wherein the dispensing device comprises a holder for holding a carrier comprising at least one receptacle, wherein the receptacle has an inlet opening for inletting liquid into the receptacle and an outlet opening for dispensing liquid from the receptacle, a dispensing head for providing a pressure on the receptacle and a control unit for executing an inventive method.

According to the invention it was recognized that a function can be provided that determines the volume of liquid to be dispensed in an accurate manner when the coefficients of the function are determined in two determination processes. The determination of the function, in particular its coefficients, occurs usually in a training process. The training process can be performed before the dispensing device is used in its regular operation.

The function can easily be determined as data with respect to volume of dispensed liquid and the volume of liquid arranged in the receptacle are considered. This means, the function can be determined by using only few parameters. It is possible that the function is determined by performing a plurality of dispensing processes. In said case for each dispensing process data with respect to volume of dispensed liquid and the volume of liquid arranged in the receptacle is provided. Thus, a large amount of data is provided so that an accurate function can be determined.

Another advantage of the invention is that at least a part of the coefficients are determined separate and/or independent of each other. This enables for example that at least some of the coefficients are determined by different people and/or at different time. This means, coefficients that are already existent and determined can be used and only a part of the coefficients has to be determined. This reduces the

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LU501475 work for determining the coefficients.

The first and second determination processes are processes in which the coefficients are determined.

The processes can be different from each other and/or can be performed separate from each other.

Additionally, the determination processes can be performed at different times. Thus, it is not necessary to determine all coefficients of the function at the same time and with the same process. Due to this flexibility of determining the coefficients, the function provides accurate results for the volume of liquid to be dispensed.

The receptacle is capable of holding and releasing a liquid sample onto a target plate only when a defined pressure, in particular pressure pulse, is applied on top of the receptacle. In particular, the pressure is applied on the liquid arranged in the receptacle. When there is no pressure pulse applied on the receptacle, no liquid is released since capillary forces keep the liquid in the cavity. That means, no liquid is released due to the atmosphere pressure acting on the liquid. A receptacle can be made out of polymers (e.g., polypropylene), metals (e.g., aluminum, copper) and/or glass. When a pressure, in particular pressure pulse is applied, on top of the receptacle a liquid droplet or liquid jet is released on a target carrier arranged below the receptacle. With “applying pressure on the liquid” it is meant that a pressure being different, in particular higher, than the atmospheric pressure is applied on the liquid.

The receptacle can be arranged in a through hole of a carrier, in particular a carrier element, in a releasable manner. That means, the connection between the receptacle and the carrier element can be disconnected without destroying the receptacle and/or the carrier element. Additionally, the receptacle can be inserted into the through hole or removed from the through hole without the use of any tools.

Alternatively, the receptacle and the carrier element can be made in one form. In said embodiment each receptacle bottom has at least one outlet opening. Said embodiment can be used if the carrier has 384 or more receptacles.

The carrier can have one or more receptacles. Carriers that have more one receptacle are also indicated as multiwell plate. In particular, carriers are known that have 6, 12, 24, 48, 96, 384, 1536 and 3456 receptacles. The receptacles are arranged in a matrix structure on the carrier element, in particular in the through holes of the carrier element.

The outlet opening of the receptacle can have a diameter between 60pm (micrometre) and 200um, in particular 100um. The dispensed liquid can be a liquid droplet or a liquid jet and/or have a volume of at least 10 nanoliters. Larger volumes are achieved by applying up to 100 pulses per second on the well.

The maximum volume of the dispensed liquid per receptacle is the receptacle volume. The receptacle can have a volume between 80 microliters to 800 microliters. The initial volume of liquid arranged in the receptacle can be between 10 microliters to 500 microliters.

The liquid depends on the usage field of the dispensing device. The liquid can contain at least one

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LU501475 biological particle. The biological particles may be microorganisms such as bacteria, archaean, yeast, fungi, and viruses or cells, DNA, RNA, or proteins. The liquid may have a single or multiple of the aforementioned biological particles. The liquid can promote the growth of the biological particles, in particular cells, arranged in the liquid. Alternatively, the liquid can comprise merely liquids, e.g. one or more chemical reagents.

The control unit is an electric or electronic unit. The control unit can comprise one or more processors for processing data. Alternatively, the control unit can be a processor for processing data. In particular, the control unit can comprise a printed circuit board.

The data for determining the function is gathered in a training process. In said training process the function, in particular its coefficients, are determined. Both will be explained below more in detail.

According to an embodiment of the invention the function for determining the volume of liquid to be dispensed can comprise at least one polynomial of n-th degree, wherein “n” is an integer number between 2 to 9, in particular 3. A polynomial of 3-th degree shows the highest accuracy. The accuracy that the determined volume of liquid to be dispensed corresponds with or basically corresponds with a predetermined volume of liquid to be dispensed can be improved by using several polynomials of n-th degree.

A control variable can be a variable by means of which liquid dispensing is controlled and/or by means of which the volume of liquid to be dispensed can be set. In particular, the control variable can be a time duration over which a valve is kept open so that pressure is applied on the liquid. The valve can be part of the dispensing device, in particular the dispensing head, and can be fluidically connected to a pressure source. Alternatively, the control variable of the dispensing process can be the pressure to be applied on the liquid. The pressure to be applied on the liquid and the time duration depend on each other. That means, by knowing one of the two values the other valve can be determined. The pressure can be time dependent. In particular, the pressure applied on the liquid can be a time dependent function. Thus, the control variable can be a pressure integral. By considering the control variable for determining the function, a function can be gathered by means of which the volume of liquid to be dispensed can be accurately determined.

The function can consist of two function parts, namely a first function part and a second function part. The volume to be dispensed can be determined by using the first function part and the second function part. In particular, the volume of liquid to be dispensed can be determined by adding a first function result and a second function result as it is described below more in detail.

The first function part can be independent of the volume of the liquid arranged in the receptacle.

Additionally or alternatively, the first function part can be dependent on the control variable, in particular the pressure applied to the liquid arranged in the receptacle. A first function result of the first function part

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LU501475 can be calculated by using a polynomial of n-th degree, in particular wherein n is an integer number between 2 to 9, in particular 3. The control variable, in particular pressure applied to the liquid, can be the variable of the polynomial. Thus, by choosing the applied pressure the first function result can be calculated. The first function part can have the following equation: 5

F1 = (ao + a1*u + a2*u2 + .... an*u" wherein “F1” is the first functional result, “u” is the control variable, “ao … an” are the constants of the polynomial of the first function part and “n” is an integer number.

The dispensing device can comprise a pressure sensor for measuring pressure within the receptacle. In particular, the pressure sensor measures the pressure in a non-liquid area of the receptacle and/or above the liquid. The pressure sensor can be attached on a line of the dispensing head by means of which the receptacle is applied with pressure. In a dispensing process, the dispensing head is arranged on the receptacle and does not contact the liquid arranged in the receptacle.

The second function part can be dependent of the volume of the liquid arranged in the receptacle.

Additionally or alternatively, the second function part can be dependent of the control variable, in particular pressure applied to the liquid arranged in the receptacle. A second function result of the second function part can be calculated by using at least one polynomial of n-th degree, in particular wherein n is an integer number between 2 to 9, in particular 3. The volume of the liquid can be multiplicated with the result of the polynomial wherein the control variable, in particular pressure applied to the liquid, can be the variable of the polynomial.

A second function result of the second function part can be calculated by using several polynomials of n- th degree, wherein n is an integer number. The number of polynomials of the second function part can corresponds with the value of the n-th degree. Each of the polynomials can be multiplicated with the volume of liquid arranged in the receptacle. However, the volumes of liquid arranged in the receptacle that are multiplicated with the polynomials differ from each other in their power. The second function part can have the following equation:

F2 = v1* (Co + C1*u + C2*U? + ... + Cn*U™) + VP * (Omer + Cme2™U + Cmes*U2 + ... + Com+1*u™) + + VI * (Cantet + C-nyme2*U + Cinymes*UZ + + Comer U") wherein “u” is the control variable, “co ... Crm+1” are the constants of the polynomial, “vI” is the volume of the liquid arranged in the receptacle and “n” and “m” are integer values. In an embodiment the “n” and “m” can have the same value.

Thus, the volume of liquid to be dispensed can be calculated as follows:

VD = F1+ F2

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LU501475 wherein ”VD” is the volume of liquid to be dispensed, “F1” is the first function result and “F2” is the second function result.

Using the second functional part being dependent of the volume of liquid arranged in the receptacle has the advantage that the volume of liquid to be dispensed can be set very accurate to the predetermined volume of liquid.

According to an embodiment at least one, in particular several, dispensing process is performed in which a volume of liquid is dispensed. The dispensing processes are performed in a training process to get data to be able to determine the coefficients of the function. In particular, the data for training the coefficients of the function can be get by performing at least one of the following methods.

The receptacle can be filled with a predetermined volume of liquid and a plurality of dispensing processes can be performed. The number of the dispensing processes and/or the volume to be dispensed can be chosen such that the receptacle is completely emptied. The dispensing processes can be performed by applying the same control variable value, in particular the same pressure on the liquid. Alternatively, it is possible to apply different pressures one after the other on the liquid. In said embodiment the fact is exploited that the volume of liquid arranged in the receptacle is only slightly reduced. A number of different pressures is predetermined and said pressures are repeatedly applied on the liquid.

The volume of liquid arranged in the receptacle can be determined by using the predetermined volume of liquid to be dispensed. The volume of liquid can be determined for each dispensing process. The predetermined volume of liquid can be provided by a person. Additionally or alternatively the volume of liquid arranged in the receptacle can be determined in the way described below when the set of the volume of liquid to be dispensed is described.

Alternatively or additionally, the volume of dispensed liquid can be measured. In particular, the volume of dispensed liquid can be determined by considering a target receptacle into which the liquid is dispensed.

When liquid is dispensed into the target receptacle in one dispensing process, the volume of dispensed liquid corresponds with the volume of liquid arranged in the target receptacle. However, if liquids of several dispensing processes are dispensed into the target receptacle, the volume of dispensed liquid per dispensing process corresponds with the volume of liquid arranged in the target receptacle divided by the number of dispensing processes. The dispensed liquid can also be measured by using an ultrasound sensor and/or a pipette. Additionally or alternatively, it is also possible to determine the dispensed liquid volume on the basis of the control variable, in particular the pressure applied on the liquid.

Said measured or analytically determined volume of dispensed liquid can be used for determining the volume of liquid arranged in the receptacle. In particular, the volume of liquid arranged in the receptacle is determined by using the measured and/or analytically determined volume of dispensed liquid.

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LU501475

For example, if the receptacle is filled with 500 pl (microliter) liquid and liquid, in particular a liquid drop, shall be dispensed in each receptacle of a 384 multiwell, the predetermined volume of liquid to be dispensed is chosen to be 13,7 nl (nanoliter). In order to ensure that the receptacle is emptied after the last dispensing process the predetermined volume of liquid to be dispensed can be chosen to be higher than the mathematical value (i.e. the value resulting from dividing the initial filing volume and the number of dispensing processes) and/or the filing volume is lowered.

After performing the aforementioned steps value triples of the control variable, in particular pressure applied on the liquid, the volume of liquid arranged in the liquid and the volume of liquid that is dispensed are known for each dispensing process.

The receptacle can be refilled with a predetermined volume of liquid and the dispensing processes are performed by applying another control variable, in particular another pressure. The predetermined volume of liquid can correspond with the predetermined volume of liquid used in the steps discussed above. The same steps can be performed as discussed above.

That means, the dispensing processes are performed by applying another control variable value, in particular another pressure, such that the receptacle is completely emptied. As discussed above this can be achieved by choosing a corresponding volume of liquid to be dispensed and/or a filing volume. As a result of the dispensing processes a plurality of value triples are provided resulting by applying the liquid with another control variable value, in particular another pressure.

It is also possible to repeat the aforementioned steps by applying the liquid with further control variable values, in particular further pressure values.

According to another embodiment the data for determining the function can be gathered as follows. The data acquisition can be performed in the same training process or in a different training processes. The receptacle can be filled with a predetermined volume of liquid and a dispensing process, in particular several dispensing processes, is performed. The number of dispensing processes can be chosen such that the receptacle is not emptied. This means, that several dispensing processes can be performed wherein the volume of liquid arranged in the receptacle can be considered as constant as the volumes of liquid that are dispensed are very low.

In a next step the receptacle can be refilled to another predetermined volume of liquid and a further dispensing process is performed. The other predetermined volume of liquid differs from the predetermined volume of liquid discussed above. The control variable value, in particular pressure applied on the liquid, can be the same for the dispensing process and the further dispensing process.

Additionally, several further dispensing processes can be performed wherein the number of further dispensing processes is chosen such that the receptacle is not emptied. In particular, the number is chosen such that the volume of liquid arranged in the receptacle can be considered as constant.

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LU501475

Likewise to the embodiment discussed above value triples of the control variable, in particular pressure applied on the liquid, the volume of liquid arranged in the liquid and the volume of liquid that is dispensed are known for each dispensing process. However, in contrary to the embodiment discussed above, the volume of liquid arranged in the receptacle is changed whereas in the other embodiment the control variable, in particular pressure applied on the liquid, is changed.

The predetermined volume of liquid to be dispensed can also be used for determining the function. At least one coefficient, in particular all coefficients, of the function can be determined by using the predetermined volume of liquid to be dispensed and the volume of dispensed liquid. Thereto the at least one coefficient, in particular all coefficients, is set such that the volume of the volume of dispensed liquid corresponds or basically corresponds with the predetermined volume of liquid to be dispensed. In particular, the at least one coefficient, in particular all coefficients, can be set such that a difference between the volume of dispensed liquid and the predetermined dispensed liquid is minimal. Additionally or alternatively at least one coefficient is determined by using a regression analysis, in particular a least square algorithm. Both options provide an easy possibility to determine the function for determining the volume of liquid to be dispensed. With “basically corresponds” it is meant that it is regarded as sufficient that the volume of liquid to be dispensed is within a predetermined range around the predetermined volume of liquid.

The at least one coefficient of the first function part is determined in the first determination process and/or the at least one coefficient of the second function is determined in the second determination process. In the first determination process at least one coefficient, in particular all coefficients, of the first function part can be determined such that the determined volume of liquid to be dispensed corresponds to a predetermined volume of liquid to be dispensed or basically corresponds to the predetermined volume of liquid to be dispensed. As discussed below the volume of liquid to be dispensed is known after performing the dispensing processed. Additionally, as discussed below the predetermined volume of liquid is entered by the user. The coefficients of the first function part can be estimated and/or determined in a trial and error method and/or analytically determined.

In the first determination process the at least one coefficient is determined independent on the volume of liquid arranged in the receptacle. In particular, in the first determination process the at least one coefficient can be determined dependent on a predetermined volume of liquid to be dispensed and the dispensed liquid of volume. Additionally, the coefficients, in particular of the second function part, do not have an influence on the coefficients determine din the first determination process and, thus, do not have to be considered. Thus, the coefficients of the first function part can be easily determined as only few parameters have to be considered.

According to an embodiment the determination of at least one coefficient in the second determination process can be dependent on at least one coefficient determined in the first determination process. In the

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LU501475 particular, the determination of at least one coefficient, in particular of the second function part, in the second determination process is dependent on the result of the first function part and the volume of dispensed liquid. The volume of dispensed liquid is known from the dispensing processes discussed above. Thus, the determination of at least one coefficient in the second determination process can be dependent on the difference between the volume of dispensed liquid and the first function part result.

In the second determination process the at least one coefficient can be set such that a difference between a second function result and the difference between the volume of dispensed liquid and the first function part result is minimal. Additionally or alternatively the at least one coefficient can be determined by using a regression analysis, in particular a least square algorithm. Both options provide an easy possibility to determine the function for determining the volume of liquid to be dispensed.

The aforementioned second determination process has the advantage that the accuracy of the function to determine the volume of liquid to be dispensed is increased. In particular, the accuracy of the function is higher than for a function in which all coefficients are determined by the same determination process.

The coefficients of the first function part and/or the second function part can be determined on the basis of the value triple data discussed above in the aforementioned manner.

A function that is determined in the aforementioned manner can be used in an operation process of the dispensing device. That means, the function can be used in a dispensing process for setting a volume of liquid to be dispensed. The operation process differs from the training process discussed above in that in the operation mode the function determined in the training process is used whereas in the training process the function is determined.

In the operation process of the dispensing device the volume of liquid to be dispensed can be set such that it corresponds to or basically corresponds to a predetermined volume of liquid. Thereto the control variable, in particular pressure applied to the liquid, can be set such that the volume of liquid dispensed in the dispensing step corresponds with or basically corresponds with the predetermined volume of liquid.

The control variable, in particular pressure applied to the liquid, can be the control variable of the setting process. That means, the control unit determines the control variable, in particular pressure to be applied to the liquid, such that the volume of liquid to be dispensed or that is dispensed in a dispensing process corresponds with or basically corresponds with the predetermined volume of liquid. Thus, the control of the dispensing process is easy as the control unit has to identify a control variable, in particular pressure value, that leads to that the volume of liquid to be dispensed corresponds with or basically corresponds with the predetermined volume of liquid. With “basically corresponds” it is meant that it is regarded as sufficient that the volume of liquid to be dispensed is within a range around the predetermined volume of liquid. The control variable, in particular pressure to be applied to the liquid, can be determined on the basis of a predetermined volume of the liquid to be dispensed and/or volume of the liquid arranged in the receptacle.

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LU501475

Using a polynomial has the advantage that a control variable of a dispensing process, in particular the pressure applied on the liquid, can easily be determined so that the determined volume of liquid to be dispensed corresponds or basically corresponds with a predetermined volume of liquid. The determination of the control variable is particularly easy if the function is an inverse function The provision of an inverse function, in particular polynomial, has the advantage that the pressure to be applied on the liquid can be calculated very accurate. This is possible as in the inverse function the function can be solved after the control variable, in particualr pressure to be applied on the liquid. Thus, in particular only, said parameter has to be set in order to receive a desired volume of liquid that is dispensed in the dispensing process.

As mentioned above, the second function part depends of the volume of liquid arranged in the receptacle.

The volume of liquid arranged in the receptacle is determined before the liquid is dispensed in the dispensing process. The volume of liquid arranged in the receptacle can be measured or estimated.

Additionally or alternatively the volume of liquid arranged in the receptacle can be determined on the basis of an initial filing volume of liquid arranged in the receptacle and the dispensed liquid volume. The initial filing volume can be the volume that e.g. a user inserts into the receptacle. Furthermore, the volume of liquid arranged in the receptacle can be determined on the basis of a stored volume of liquid arranged in the receptacle and the dispensed liquid volume, wherein the stored volume of liquid arranged in the receptacle corresponds with the volume of liquid arranged in the receptacle before a previous dispensing process is performed. The determined volume of liquid arranged in the receptacle can be stored and thus can be used in future dispensing process as “stored volume of liquid arranged in the receptacle’.

The dispensed liquid volume can correspond with the predetermined volume of liquid dispensed in a previous dispensing process. Alternatively, the dispensed liquid volume can correspond with the sum of predetermined volumes of liquids dispensed in several previous dispensing processes. As discussed above the predetermined volume of liquid is chosen by a user. It is also possible to measure the dispensed liquid volumes and to use said measured volume for determining the volume of liquid arranged in the receptacle. Additionally or alternatively, it is also possible to determine the dispensed liquid volume on the basis of the pressure applied on the liquid.

The dispensing device can comprise a target carrier holder for a target carrier. The target carrier holder can comprise at least one target receptacle for receiving the dispensed liquid. The target carrier holder can be arranged below the receptacle or the carrier for carrying the at least one receptacle.

The value of the volume of liquid arranged in the receptacle can depend of a predetermined threshold. In particular, the value of volume of liquid can be set to 0 when the value of the determined volume of liquid corresponds with the predetermined threshold or is lower than the predetermined threshold. In this case the second function result is 0. Such an embodiment has the advantage that the volume of liquid to be

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LU501475 dispensed can be determined faster in comparison to an embodiment when the first and second result have to be calculated. This is possible as it has been recognized that the volume of liquid arranged in the receptacle has no or no significant influence on the accuracy of setting the volume of liquid to be dispensed to correspond or basically correspond with the predetermined volume of liquid. The threshold can be 20 microliter.

In a dispensing process of the dispensing device operated in the operation process, the volume of liquid to be dispensed that is set as discussed above is dispensed.

According to an aspect of the invention a control unit is provided for executing the inventive method. In particular, the control unit is configured that it can perform the method steps discussed above. According to another aspect of the invention computer program product is provide wherein the computer program product comprises instructions which, when the program is executed by a control unit, cause the control unit to carry out the steps of the inventive method. Additionally, a computer-readable data carrier is provided wherein the computer-readable data carrier has stored thereon the computer program product.

Also a data carrier signal is provided wherein the data carrier signal carries the computer program product.

In the figures, the subject matter of the invention is shown schematically, with identical or similarly acting elements being mostly provided with the same reference signs. Therein shows:

Fig. 1 a cross section view of a part of a dispensing device according to a first embodiment,

Fig. 2 a cross section view of a part of a dispensing device according to a second embodiment,

Fig. 3 a flow chart of the method for setting the volume of liquid to be dispensed according to the invention of a dispensing device according to a first embodiment,

Fig. 4 a flow chart of the training process and

Fig. 5 a perspective view of a part of a dispensing device.

Fig. 1 shows a cross section of a part of a dispensing device 5 according to a first embodiment. In particular, fig. 1 shows a hollow dispensing line 15 of a dispensing head 8. The dispensing head 8 is arranged in its dispensing position in which a dispensing line 15 is arranged on a receptacle 2 comprising liquid 1. Thus, the dispensing head 8 is not in direct contact with the liquid 1. The dispensing head 8 comprises a seal 16 that is arranged between the dispensing line 15 and the receptacle. Additionally, the dispensing is electrically connected with a non-shown control unit. The control unit can control at least one valve arranged in the dispensing head for applying the pressure to the liquid arranged in the receptacle. In order to apply a pressure on the liquid a non-shown valve is opened.

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LU501475

The receptacle 2 is arranged on a carrier 7 and comprises an outlet opening 4 at its bottom. Additionally, the receptacle comprises an inlet opening 3 through which liquid 1 can be inserted into the receptacle 2.

The inlet opening 3 and the outlet opening 4 are arranged at ends of the receptacle 2 that opposite to each other.

By applying a pressure on the liquid 1 by means of the dispensing line 15 a droplet is dispensed from the receptacle 2. The pressure apply is indicated by the arrow in figure 1. The pressure enters the receptacle via the inlet opening 3. A pressure sensor 10 is attached on the dispensing line 15. The pressure sensor 10 is configured to measure the pressure arranged in the area of the receptacle that is arranged above the liquid. Additionally, it is possible to measure a time duration in which the pressure is applied to the liquid 1.

Fig. 2 shows a cross section of a part of a dispensing device 5 according to a second embodiment. The second embodiment differs from the first embodiment in the structure of the carrier 7. The carrier 7 does not have a receptacle 2 that can be released from the carrier 7. The receptacle 2 and the carrier 7 are formed as one part. Each of the receptacles 2 has the outlet opening 4 at its bottom. Likewise, to the embodiment shown in fig. 1, The outlet opening 4 has such a size that capillary forces are so high that liquid 1 cannot flow out of the receptacle 2 if no pressure is applied on the liquid by means of the dispensing head 8. As is evident from fig. 2, the control unit 9 is connected with the dispensing head 8.

A target carrier 12 is arranged below the carrier 7. The target carrier 12 comprises a plurality of target receptacles 13 for receiving the liquid dispensed from receptacles 2 of the carrier 7. A target carrier holder 11 is provided that holds the target carrier 12. The target carrier holder 11 moves the target carrier 12 relative to the carrier 7. The control unit 9 is electrically connected with the target carrier holder 11.

The dispensing head 8, the carrier 7 and the target carrier 12 can move relative to each other. The control unit 9 controls the movement of at least one of said components with respect to the remaining components.

Fig. 3 shows a flow chart of the method for setting the volume of liquid to be dispensed according to the invention a part of a dispensing device 5 according to the first or second embodiment. In a first step S1 the user enters the predetermined volume of liquid 1 to be dispensed into the dispensing device 5.

Thereto, the dispensing device 5 can have an input means like a keyboard and/or touch display. The user can enter one volume of liquid to be dispensed by each receptacle. Alternatively, it is possible to enter a volume of liquid to be dispensed separate for each receptacle 2.

In a second step S2, a control unit 14 sets a volume of liquid 1 to be dispensed by considering the entered, predetermined volume of liquid to be dispensed. In particular, the control unit 14 sets the volume of liquid 1 to be dispensed such that it corresponds or basically corresponds with the predetermined

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LU501475 volume of liquid 1 that was entered in the first step S1. Thereto, the control unit 14 controls the dispensing head 8 such that a control variable, in particular the applied pressure or the time duration over which the valve is kept open, is set such so that the determined volume of liquid that is dispensed corresponds or basically corresponds with the predetermined volume of liquid. The pressure can be time dependent. In particular, the pressure applied on the liquid can be a time dependent function. Thus, the control variable can be a pressure integral.

In the following, it is explained more in detail how the volume of liquid to be dispensed is set by the control unit. À possibility is to use a function, in particular a polynomial, to calculate the volume of liquid to be dispensed. The function has a first function part and a second function part. In particular, the following equations are used to calculate the volume of liquid to be dispensed wherein each of the polynomials is a polynomial of 3Ÿ degree:

VD =F1+F2

F1 = (ao + a1*u + a2*u? + as*u®)

F2 = v1* (Co + C1*u + Ca*u? + Cs*U*) + VI? * (C4 + Cs*U + Co*U? + C7*U*) + VI * (cs +

Co*U + C1o*U? + C11*US) wherein ”VD” is the volume of liquid to be dispensed, “F1” is the first function result and “F2” is the second function result, “u” is the control variable, “co ... cnm+1” are the constants of the polynomial, “vil” is the volume of the liquid arranged in the receptacle and “n” and “m” of the equation shown above have the value “3”.

The volume of liquid to be dispensed VD corresponds with the sum of the first function result and the second function result.

As is discussed below more in detail, the coefficients of the first function and of the second functions are determined in a training process. The training process is made in a step SO that is previous to the first step S1 and is explained in figure 4 more in detail.

The first function result F1 is calculated by using a polynomial of 3%“ degree wherein the pressure u applied on the liquid 1 is the variable of the polynom. The second function result is a sum of three polynomials of 3% degree, respectively. The control varbiable u applied on the liquid 1 is the variable of each of the polynomials. Each of the polynoms is multiplicated with the volume of liquid vl that is arranged in the receptacle 2. This volume of liquid vl arranged in the receptacle 2 can be measured and/or analytically determined.

The control unit sets the control variable u such that the calculated volume of liquid VD to be dispensed corresponds or basically corresponds with the predetermined volume of liquid to be dispensed that was entered in the first step S1. As the function is an inverse function the control unit 9 can easily determine

15.02.2022 005A0008LU 14

LU501475 the control variable.

In a third step S3 the control unit 9 acts on the dispensing head 8 such that the determined pressure is applied on the liquid 2. This leads to that liquid is dispensed from the receptacle wherein the dispensed liquid has the volume of liquid to be dispensed that was determined in the second step S2.

Fig. 4 shows a flow chart of a training process for determining the function for determining the volume of liquid to be dispensed. As is explained above, the function is a polynomial function.

In a first substep S01 data is determined that is needed to determine the coefficients of the polynomial function, i.e. the coefficients of the first and second function part. Thereto, according to a first option the receptacle is filled with a predetermined volume of liquid, e.g. 500 ul, and a plurality of dispensing processes are performed. The number of the dispensing processes and/or the volume to be dispensed are chosen such that the receptacle is completely emptied. As the target carrier has 384 receptacles the volume of liquid to be dispensed is 1,3 ul. By knowing the volume of dispensed liquid, the volume of liquid arranged in the receptacle can be determined. Each of the dispensing processes is performed by applying the same pressure on the liquid. Alternatively, the dispensing process could be performed by using the same time duration over which the valve is kept open. Alternatively, it is possible to apply different pressures one after the other on the liquid. In said embodiment the fact is exploited that the volume of liquid arranged in the receptacle is only slightly reduced. A number of different pressures is predetermined and said pressures are repeatedly applied on the liquid.

After the receptacle 2 is emptied, the receptacle is refilled with a predetermined volume of liquid and the dispensing processes are performed by applying another pressure. The predetermined volume of liquid can correspond with the predetermined volume of liquid used in the steps discussed above. However, it is also possible that the volumes of the filled liquids differ from each other. The aforementioned steps are repeated until the receptacle is emptied again wherein the liquid is applied with the another pressure. The volume of liquid that is dispensed in the target receptacle 13 is measured so that the volume of dispensed liquid can be assigned to each dispensing process.

Alernatively or additionally, according to a second option the data for determining the polynomial function can be gathered as follows. The receptacle can be filled with a predetermined volume of liquid and a dispensing process, in particular several dispensing processes, is performed. The number of dispensing processes can be chosen such that the receptacle is not emptied. This means, that several dispensing processes can be performed wherein the volume of liquid arranged in the receptacle can be considered as constant as the volumes of liquid that are dispensed are very low.

In a next step the receptacle can be refilled to another predetermined volume of liquid and a further dispensing process is performed. The other predetermined volume of liquid differs from the predetermined volume of liquid used in the dispensing process. The pressure applied on the liquid or time

15.02.2022 005A0008LU 15

LU501475 duration can be the same for the dispensing process and the further dispensing process. Additionally, several further dispensing processes can be performed wherein the number of further dispensing processes is chosen such that the receptacle is not emptied. In particular, the number is chosen such that the liquid arranged in the receptacle can be considered as constant. The volume of liquid that is dispensed in the target receptacle 13 is measured so that the volume of dispensed liquid can be assigned to each dispensing process.

In both options a plurality of value triples of control variables, in particular the pressure applied to the liquid, the volume of liquid arranged in the receptacle and the volume of liquid that is dispensed are determined. Said values are used for determining the coefficients of the polynomial function as explained below.

In a second substep S02 the coefficients for the first function part are determined in the first determination process. Thereto, the coefficients of the first function part F1 are set such that the first function result corresponds or basically corresponds with the volume of dispensed liquid that is gathered in the data acquisition process discussed above.

In a third substep S03 the coefficients for the second function part are determined in the second determination process. Thereto, a difference between the gathered volume of dispensed liquid and the first function result F1 is determined. In the second determination process the coefficients of the second function part are set such that the second function part result corresponds or basically corresponds with the difference between the gathered volume of dispensed liquid and the first function result F1. Thereto, the coefficients are set such that the difference of the predetermined volume of liquid to be dispensed and the volume of liquid that is dispensed is minimal. Additionally or alternatively, a regression analysis can be performed in order to determine the coefficients of the second function part.

After performing the substeps, the coefficients of the function are determined so that the dispensing device can be used in the operation process in which volume of liquid is dispensed after a predetermined volume of liquid is commanded by the user.

Also, the device 26 comprises a holder 6, in which the carrier 7 is mounted in a detachable manner. The dispensing head 8 is moveable relative to the holder 6 by means of a motor system (not shown in the figure). In particular, the dispensing head 8 can be moved relative to the carrier 7 so that the liquid of different receptacles 2 can be dispensed in sequence. Alternatively or additionally, it is possible that the carrier 7 moves relative to the dispensing head 8.

15.02.2022 005A0009LU 16

LU501475

Reference Signs: 1 liquid 2 receptacle 3 inlet opening 4 outlet opening 5 dispensing device 6 holder 7 carrier 8 dispensing head 9 control unit 10 pressure sensor 11 target carrier holder 12 target carrier 13 target receptacle 15 dispensing line 16 seal

F1 first function result

F2 second function result an coefficient of first function

Cn coefficient of second function vl volume of liquid arranged in receptacle

Claims

15.02.2022 005A0008LU 17 LU501475 Patent Claims

1. Method for determining a function determining a volume of liquid to be dispensed from a receptacle (2) comprising an inlet opening (3) for inletting a liquid (1) into the receptacle (2) and an outlet opening (4) for dispensing liquid from the receptacle (2) when a pressure is applied on the liquid (1), wherein at least one coefficient of the function is determined by using a first determination process and at least one other coefficient of the function is determined by using a second determination process.

2. Method according to claim 1, characterized in that a. the function is at least one polynomial of n-th degree and/or in that b. the volume of liquid to be dispensed is determined by using several polynomials of n-th degree and/or in that

C. the volume of liquid to be dispensed is set by using at least one polynomial of n-th degree, wherein n is an integer number between 2 to 9, in particular 3.

3. Method according to claim 1 or 2, characterized in that the function comprises a first function part and a second function part, wherein the volume of liquid that is dispensed in the dispensing process is the sum of a first function result (F1) and a second function result (F2).

4. Method according to claim 3, characterized in that a. the first function part is independent of the volume of the liquid (vl) arranged in the receptacle (2) and/or in that b. the first function part is dependent of a control variable of a dispensing process, in particular the pressure applied to the liquid (1) arranged in the receptacle (2).

5. Method according to claim 3 or 4, characterized in that a. a first function result (F1) is calculated by using a polynomial of n-th degree, in particular wherein n is an integer number between 2 to 9, in particular 3, and/or in that b. a first function result (F1) is calculated by using a polynomial of n-th degree, wherein the control variable, in particular the pressure applied to the liquid (1), is the variable of the polynomial and/or in that

C. a first function result (F1) is calculated by using the following equation F1 = (a0 + aı*u + ... + au") wherein “u” is a control variable, “ao ... an” are the constants of the polynomial of the first function and “n” is an integer value.

6. Method according to at least one of the claims 3 to 5, characterized in that a. the second function part is dependent of the volume of the liquid (vl) arranged in the

15.02.2022 005A0008LU 18 LU501475 receptacle (2) and/or in that b. the second function part is dependent of the control variable, in particular pressure applied to the liquid (1) arranged in the receptacle (2).

7. Method according to at least one of the claims 3 to 6, characterized in that a. a second function result (F2) is calculated by using at least one polynomial of n-th degree, in particular wherein n is an integer number between 2 to 9, in particular 3, wherein the volume of liquid (vl) is multiplicated with the result of the polynomial and/or in that b. a second function result (F2) is calculated by using at least one polynomial of n-th degree, wherein the control variable, in particular pressure applied to the liquid (1), is the variable of the polynomial and the volume of liquid (vl) is multiplicated with the result of the polynomial.

8. Method according to at least one of the claims 3 to 7, characterized in that a. a second function result (F2) is calculated by using several polynomials of n-th degree, in particular wherein the number of polynomials corresponds with the value of the n-th degree and/or in that b. a second function result (F2) is calculated by using the following equation: F2 = v1* (Co + C1*u + C2*U? + ... + Cn*U™) + VP * (Omer + Cme2™U + Cmes*U2 + ... + Com+1*u™) + + VI * (Cantet + C-nyme2*U + Cinymes*UZ + + Comer U") wherein “u” is the control variable, “co ... Crm+1” are the constants of the polynomial, “vI” is the volume of the liquid arranged in the receptacle and “n” and “m” are integer values.

9. Method according to at least one of the claims 1 to 8, characterized in that at least one dispensing process is performed in which a volume of liquid is dispensed.

10. Method according to claim 9, characterized in that for each dispensing process a. the volume of dispensed liquid is measured and/or in that b. the liquid is dispensed into a target carrier and the volume of dispensed liquid per dispensing process is determined on the basis of the volume of liquid stored in the target carrier and/or the number of dispensing processes and/or in that

C. the volume of dispensed liquid and/or the volume of the liquid arranged in the receptacle and/or control variable value is determined and/or stored.

11. Method according to at least one of the claims 1 to 10, characterized in that a. the at least one coefficient, in particular all coefficients, of the first function part is determined in the first determination process and/or in that

15.02.2022 005A0008LU 19 LU501475 b. the at least one coefficient, in particular all coefficients, of the second function part is determined in the second determination process.

12. Method according to at least one of the claims 1 to 11, characterized in that in the first determination process at least one coefficient, in particular all coefficients, of the first function part is determined such that the determined volume of liquid to be dispensed corresponds to a predetermined volume of liquid to be dispensed or basically corresponds to the predetermined volume of liquid to be dispensed.

13. Method according to at least one of the claims 1 to 15, characterized in that a. in the first determination process the at least one coefficient, in particular all coefficients, is determined independent on the volume of liquid arranged in the receptacle and/or in that b. in the first determination process the at least one coefficient, in particular all coefficients, is determined dependent on a predetermined volume of liquid to be dispensed and the dispensed liquid of volume and/or in that

C. in the first determination process the at least one coefficient, in particular all coefficients, is determined dependent on a control variable of a dispensing process and/or in that d in the first determination process the at least one coefficient, in particular all coefficients, is determined independent on the coefficients determined in the second determination process.

14. Method according to at least one of the claims 1 to 13, characterized in that the determination of at least one coefficient, in particular all coefficients, in the second determination process is dependent on at least one coefficient, in particular all coefficients, determined in the first determination process.

15. Method according to at least one of the claims 1 to 14, characterized in that a. the determination of at least one coefficient, in particular all coefficients, in the second determination process is dependent on the first function result and the volume of dispensed liquid and/or in that b. the determination of at least one coefficient, in particular all coefficients, in the second determination process is dependent on the difference between the volume of dispensed liquid and the first function result.

16. Method according to at least one of the claims 1 to 15, characterized in that a. in the second determination process the at least one coefficient is set such that a difference between a second function result and the difference between the volume of dispensed liquid and the first function part result is minimal and/or in that b. in the second determination process the at least one coefficient is determined by using a regression analysis, in particular a least square algorithm.

15.02.2022 005A0008LU 20 LU501475

17. Method according to at least one of the claims 1 to 16, characterized in that the determined function is used in a dispensing process for setting the volume of liquid to be dispensed.

18. Method according to claim 17, characterized in that a. the volume of liquid (vl) to be dispensed is set such that it corresponds to or basically corresponds to a predetermined volume of liquid and/or in that b. the control variable is set such that the volume of liquid dispensed in the dispensing step corresponds with a predetermined volume of liquid and/or in that

C. the control variable is determined on the basis of a predetermined volume of the liquid to be dispensed and/or volume of the liquid arranged in the receptacle (2).

19. Method according to claim 17 or 18, characterized in that the volume of liquid (vl) arranged in the receptacle (2) is determined before the liquid (1) is dispensed in the dispensing process.

20. Method according to at least one of the claims to 17 to 19, characterized in that a. the volume of liquid (vl) arranged in the receptacle (2) is determined on the basis of an initial filing volume of liquid in the receptacle (2) and the dispensed liquid volume and/or in that b. the volume of liquid (vl) arranged in the receptacle (2) is determined on the basis of a stored volume of liquid arranged in the receptacle (2) and the dispensed liquid volume, wherein the stored volume of liquid arranged in the receptacle (2) corresponds with the volume of liquid (vl) arranged in the receptacle before a previous dispensing process is performed.

21. Method according to claim 20, characterized in that a. the dispensed liquid volume corresponds with the predetermined volume of liquid dispensed in a previous dispensing process or with the sum of predetermined volumes of liquids dispensed in several previous dispensing processes and/or in that b. the dispensed liquid volume is determined on the basis of the control variable.

22. Method according to at least one of the claims 17 to 21, characterized in that a. the value of the determined volume of liquid (vl) arranged in the receptacle depends of a predetermined threshold or in that b. the value of the determined volume of liquid (vl) arranged in the receptacle depends of a predetermined threshold, wherein the value of the volume of liquid arranged in the receptacle is set to 0 when the value of the determined volume of liquid corresponds with the predetermined threshold or is lower than the predetermined threshold.

23. Method according to at least one of claims 1 to 22, characterized in that in a dispensing process

15.02.2022 005A0009LU 21 LU501475 the set volume of liquid is dispensed.

24. Control unit for executing the method according to at least one of the claims 1 to 23.

25. Computer program product comprising instructions which, when the program is executed by a control unit, cause the control unit to carry out the steps of at least one of the methods of claims 1 to 23.

26. Computer-readable data carrier having stored thereon the computer program product of claim 25.

27. Data carrier signal carrying the computer program product of claim 25.

28. Dispensing device (5) for dispensing liquid (1), wherein the dispensing device (5) comprises a holder (6) for holding a carrier (7) comprising at least one receptacle (2), wherein the receptacle (2) has an inlet opening (3) for inletting liquid (1) into the receptacle (2) and an outlet opening (4) for dispensing liquid (1) from the receptacle (2), a dispensing head (8) for providing a pressure on the receptacle (2) and a control unit (9) according to claim 24.

29. Dispensing device (5) according to claim 28, characterized in that the dispensing device (5) comprises a pressure sensor (10) for measuring pressure within the receptacle (2).

30. Dispensing device (5) according to claim 28 or 29, characterized in that the dispensing device (5) comprises a target carrier holder (11) for a target carrier (12) comprising at least one target receptacle (13) for receiving the dispensed liquid.