Automatic trajectory correction method and system for acoustically generated droplets

Abstract

Systems and methods for detecting the position or trajectory of and / or controlling the direction of in-flight charged droplets are described herein. The systems and methods are useful for determining the location of charged droplets in real time based on signals induced in electrodes of a sensor surrounding an aperture through which the charged droplets pass during flight from a source well to a target. The signals from the sensor electrodes can be measured and used to determine the position or trajectory of the droplets. The systems and methods are useful for correcting the trajectory of charged droplets in real time, such as based on determined locations identified as having trajectories that deviate from the target. The trajectory can be corrected by applying a voltage to electrodes surrounding the aperture through which the charged droplets pass during flight from a source well to a target.

Description

[Background technology]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of and priority to U.S. Provisional Patent Application No. 63 / 400,700, filed August 24, 2022, and entitled "AUTOMATIC TRAJECTORY CORRECTION METHODS AND SYSTEMS FOR ACOUSTIC GENERATED DROPS," which is incorporated herein by reference in its entirety.

[0002] The discovery of new and useful materials, the characterization of materials, the performance of tests, and other such procedures can depend on the ability to create and characterize new compositions. As a result, recent research related to physical, chemical, biological, or other material properties has focused on developing and implementing methods and systems for synthesizing and evaluating potentially useful chemical compounds, as well as performing tests on and analyzing various materials. In particular, rapid combinatorial methods have been developed to address the general need in the art for systematic, efficient, and economical techniques for materials synthesis, as well as methods for analyzing and screening novel materials for useful properties.

[0003] Rapid combinatorial methods often involve the use of array technologies, which require precise dispensing of fluids, each with precisely known chemical composition, concentration, stoichiometry, reagent ratios, and / or volume. Such array technologies can be employed to perform a variety of synthetic processes and evaluations. Array technologies can employ a large number of different fluids to form multiple reservoirs, which, when properly arranged, generate a combinatorial library. Several fluid dispensing techniques, such as pin spotting, pipetting, inkjet printing, and acoustic ejection, have been explored to perform combinatorial techniques.

[0004] Many of these techniques, however, possess inherent drawbacks that must be addressed before the fluid dispensing accuracy and efficiency required for combinatorial methods can be achieved. For example, some fluid dispensing systems are constructed using networks of tubing or other fluid transport vessels. In particular, the tubing can trap air bubbles, and nozzles can become clogged with lodged particulates. As a result, system failures can occur, causing erroneous results. Furthermore, cross-contamination between reservoirs of compound libraries can occur due to improper flushing of tubing and pipette tips during fluid transfer events. Cross-contamination can easily lead to inaccurate and misleading results.

[0005] Acoustic ejection offers several advantages over other fluid dispensing techniques. In contrast to inkjet devices, nozzleless or tipless fluid ejection devices are not subject to clogging and their associated disadvantages, such as misdirected fluid or improperly sized droplets. Furthermore, acoustic ejection does not require the use of tubing or involve invasive mechanical actions, such as those associated with introducing a pipette tip into a reservoir of fluid, and thus may, among other things, reduce the risk of contamination. In addition, acoustic ejection can achieve higher levels of precision and accuracy and can be used to dispense very small volumes of fluid, which may significantly reduce reagent costs.

[0006] Acoustic ejection has been described in several patents. For example, U.S. Pat. No. 4,308,547 to Lovelady et al. describes a liquid droplet emitter that uses acoustic principles to eject droplets from a body of liquid onto a moving document, resulting in the formation of characters or barcodes on the document. A nozzleless inkjet printing device is used, in which controlled droplets of ink are propelled by acoustic forces generated by a curved transducer at or below the ink surface. Similarly, U.S. Pat. No. 6,666,541 describes a device for acoustically ejecting multiple fluid droplets toward separate locations on a substrate surface for deposition thereon. The device includes an acoustic radiation generator that can be used not only to eject fluid droplets from a reservoir but also to generate a detection acoustic wave that is transmitted to the fluid surface of the reservoir and becomes a reflected acoustic wave. The characteristics of the reflected acoustic radiation can then be analyzed to assess the acoustic energy level produced by the acoustic radiation generator at the fluid surface.Acoustic ejection may therefore provide an additional advantage in that the appropriate use of acoustic radiation provides feedback related to the process of acoustic ejection itself.

[0007] Variations in the initial conditions of droplet formation at the meniscus, including droplet velocity and direction, as well as variations in forces on the droplet during its flight path (such as air drag and electrostatic forces on charged droplets), result in variations in droplet placement at the target.

[0008] When the target is a destination microplate well and multiple droplets are transferred, it is desirable for all droplets to fuse and coalesce into a single larger droplet at the target. However, in some cases, the droplets land on the target in a random pattern.

[0009] Many previous solutions rely on passive approaches to minimize sources of variation. Some exemplary techniques “dampen” the meniscus and reduce fluid surface variability, but this is not a “comprehensive” solution. Typical existing solutions involve some type of calibration solution for non-real-time droplet placement verification, which can be a time-consuming manual process. For example, fluid-sensitive paper can be used to determine where a droplet lands after a test droplet is ejected. In addition to being time-consuming and manual, such non-real-time processes do not allow for timely adjustments and, in some cases, can result in significant costs due to droplet ejection failures. While there are some existing solutions that can provide real-time verification of droplet placement, these involve the use of large, expensive, and complex machinery. For example, while some optical systems, such as phase Doppler interferometer systems, can be used to detect droplet position in real time, these are large, expensive, and typically use laser systems, which can be desirably avoided.

[0010] There is a need in the art for improved methods and apparatus that are capable of accurately detecting droplet ejection, droplet velocity, and droplet location during transit (which provide real-time data) that do not rely on optical lasers, which are bulky and expensive. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] U.S. Patent No. 4,308,547 Summary of the Invention [Means for solving the problem]

[0012] Examples of the inventions encompassed by this disclosure are defined by the claims below, rather than by this summary. This summary is a high-level overview of various aspects and introduces some of the concepts that are further described in the Detailed Description section below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used alone to determine the scope of the claimed subject matter. The subject matter should be understood by reference to the entire disclosure, including the following description, all drawings, and claims.

[0013] While typical systems rely on manual calibration and / or large, expensive optical tracking systems for droplet ejection tracking of acoustic droplet ejectors, the devices, systems, and methods provided herein enable real-time tracking and control of charged droplets using a compact, low-cost system. While the examples described herein may show or be referenced to acoustic droplet ejection systems, the techniques and systems described herein may be applied to pressure-based systems (e.g., inkjet), microfluidic systems, or any other suitable droplet generation system or component (e.g., fluorescence-activated cell sorters, fluorescence-activated single-drop dispensers, precision micropump systems, piezoelectric-based active droplet generators, etc.). While real-time tracking can be achieved using optical tracking systems, such systems may add additional complexity to the droplet ejection system and affect system usability. Other techniques for non-real-time tracking require manual calibration and may interrupt workflow. The real-time measurements described herein provide increased manufacturing workflow efficiency and rapid optimization of droplet generator calibration. The real-time control schemes described herein further provide droplet position accuracy and repeatability, which can avoid repeated calibration through a real-time feedback system. The systems and methods can also enable efficient coupling of droplet generators (e.g., acoustic droplet ejection systems) to the inlet of secondary devices, such as mass spectrometers or other analytical systems. The devices, systems, and methods described herein are particularly useful for real-time tracking and control, for example, to confirm or align droplet placement in a mass spectrometer or other analytical system during sample placement for analysis. Precision droplet placement may also enable drop-on-drop chemistry or the creation of microarrays at the bottom of a well. Currently, the inherent distribution of droplet trajectories makes these tasks difficult, but the ability to correct the placement of each droplet during transport via the techniques described herein opens up new areas of research. Many applications require trains of droplets dispensed at hundreds of hertz.Using real-time analog feedback correction according to the techniques described herein, each drop in the train can be addressed as the measurement signal is adjusted based on small variations measured.

[0014] The present disclosure provides systems for detecting, monitoring, and controlling charged droplets from droplet generators, such as acoustic droplet ejection systems. One general aspect includes a device for detecting and / or controlling charged droplets from a droplet generator. The device includes a sensor element and / or control element (e.g., one or more multilayer printed circuit boards) having one or more conductive layers separated or supported by insulating layers, and the sensor element or control element may define one or more apertures through which the charged droplets pass. In some examples, the sensor element and / or control element may be fabricated as one or more multilayer printed circuit boards, although it should be understood that the sensor or control element may take any suitable form.

[0015] In some embodiments, droplets ejected by a droplet generator may be required to arrive at a target within a certain tolerance. For example, a particular application may impose a placement tolerance, such as within a dimension that is a fraction of the droplet diameter (e.g., within 100%, 75%, 50%, 25%, 10%, or 5% of the droplet diameter). Such a placement tolerance may ensure, for example, that droplets land on the target or that different droplets coalesce upon reaching the target. In some cases, droplets may arrive off-target by no more than about 200% of the droplet diameter (e.g., a 2.5 nL droplet having a diameter of 168 microns may arrive 400 microns off-target). In preferred cases, droplets consistently land at or within a distance from the target location that is no more than 125% of the droplet diameter, with fewer than 1 in 1,000 droplets landing more than 125% of the droplet diameter from the target location. After the initial droplet, subsequent droplets directed to the target location may desirably merge, coalesce, and mix into a single larger droplet. Ideally, there should be no off-target droplets that land separately from the main droplet, no scattering, and no spray. Droplet placement on the target can accommodate not only the widest possible range of initial velocity and direction at droplet formation, but also variation along the droplet flight path. In some examples, the target may be a well in a microplate, a microfluidic device, or an inlet or orifice associated with an analytical instrument, device, or system. The droplets may be sized to properly reach the target without colliding with the sides or walls of the inlet or orifice. For example, the orifice may have a diameter greater than or about 130% of the diameter of the droplet, such as greater than or about 150%, 200%, 250%, 300%, 350%, 400%, 450%, 500% of the diameter of the droplet, or about 130% to about 1,000%.

[0016] PCT International Application No. PCT / US2022 / 017988, filed February 25, 2022, and U.S. Provisional Application No. 63 / 154,633, filed February 26, 2022 (incorporated herein by reference) provide additional details and examples of techniques, devices, and methods for sensing and / or controlling droplet trajectory.

[0017] In some examples, the sensor element may include three or more conductive layers and two or more insulating layers. In some examples, the sensor element or an internal layer of the sensor element includes a segmented conductive layer having multiple segmented sections electrically isolated or independent from each other, and the multiple segmented sections may be arranged around the periphery of an aperture in the segmented conductive layer. The device may also include circuit elements (e.g., one or more transimpedance amplifiers) electrically coupled to each of the segmented sections. Each segmented section of the sensor element is positioned to provide an induced current to the circuit element when a charged droplet passes through the aperture. The circuit elements may include one or more transimpedance amplifiers that generate measurements (e.g., voltage signals) based on or proportional to the induced current. The device may also include one or more computing devices or means that can receive measurements from the circuit elements and generate a weight map that identifies the position of the charged droplet within the aperture based on the magnitude of the measurements. In some examples, the signals may be processed using a computing device, circuitry, an analog-to-digital converter, software, or other such systems.

[0018] In some examples, the control element may include one or more conductive layers and one or more insulating layers. In one example, the conductive layer of the control element may include a segmented conductive layer having multiple segmented segments that are electrically insulated or independent from one another, and the multiple segmented segments may be arranged around the periphery of an opening in the segmented conductive layer. The device may also include one or more voltage generators and / or voltage controllers for applying a potential to each of the segmented segments to generate an electric field of sufficient orientation and magnitude to alter the trajectory of the charged droplet as it passes through the opening.

[0019] The device may optionally include one or more computing devices or means capable of determining the voltage to be applied to each of the divided sections to achieve a particular deflection of the droplet trajectory. In some cases, the voltage may be determined based on or using a signal representative of or useful for deriving the position of the charged droplet determined by passing the charged droplet through a sensor element. In some examples, the signal may be processed using a computing device, circuitry, analog-to-digital converter, software, or other such system to determine the appropriate voltage to be applied to the divided sections of the conductive layer.

[0020] In some examples, a voltage generator and / or voltage controller can receive one or more signals and directly generate voltages to apply potentials to each of the divided sections of the control element to generate an electric field of sufficient orientation and magnitude to alter the trajectory of the charged droplets as they pass through the aperture. In some examples, the signals used to generate voltages to adjust the trajectory and / or position of the charged droplets in the control element can be based on induced currents generated when the charged droplets pass through the aperture of the sensor element. For example, the signals can be proportional to the induced currents, optionally with or without an applied bias level. In some examples, the bias level can be a DC bias, but the bias level can optionally be a time-varying waveform. In some examples, individual bias levels are applied to each signal representing or corresponding to the induced currents in the different sections. Optionally, the bias applied to one or more signals can correspond to one of the signals or its inverse. For example, a first signal may have its inverse applied as a bias (with or without a DC offset) such that the resulting signal used to generate a first voltage for adjusting trajectory or position is zero or offset from zero, while a second signal may have the inverse of the first signal applied as a bias (with or without a DC offset) such that the resulting signal used to generate a second voltage for adjusting trajectory or position is characteristic of (e.g., proportional to) the difference between the first and second signals (with or without a DC offset).

[0021] Optionally, generating voltages to apply potentials to each of the divided sections of the control element to generate an electric field of sufficient orientation and magnitude to alter the trajectory of charged droplets as they pass through the aperture can be accomplished without any calculations. In other words, the voltage generator and / or voltage controller, in some examples, may not employ or use a computing device to determine the voltages to apply potentials to each of the divided sections of the control element to achieve a desired level of control over the trajectory and / or position of charged droplets. In some examples, the signal provided to the voltage generator and / or voltage controller may comprise, correspond to, be based on, or be proportional to a signal measured by the sensor element, such as one or more induced currents generated as charged droplets pass through the aperture of the sensor element.

[0022] Advantageously, the induced current sensed as a charged droplet passes through a sensor aperture, or a signal based on or proportional to the induced current, can be used to adjust the trajectory or position of the charged droplet using a control element, such as when the charged droplet passes through an aperture in the control element. It should be understood that in some examples, the induced current sensed at each of the divided sections of the sensor element may correspond to a time-dependent waveform. Similarly, the voltage applied to each of the divided sections of the control element may correspond to a time-dependent waveform. According to some examples described herein, the time-dependent voltage waveform applied to each divided section of the control element may be based on or proportional to the corresponding time-dependent induced current waveform detected at the divided section of the sensor element, optionally with a time shift or time delay applied. In other words, in some examples, the induced current or other proportional signal derived from or based on the induced current may be fed directly to a voltage generator and / or voltage controller, optionally adjusted or with a different magnitude and / or opposite polarity than the induced current or proportional signal, and / or optionally with a time shift or time delay applied. In some cases, the induced current or other signal based on or proportional to it is subject to filtering and / or smoothing prior to and / or after conversion to a voltage for application to a section of the control element by a voltage controller.

[0023] In another example, a system for detecting charged droplets from a charged droplet generator includes a sensing device, such as the sensor element already discussed, having an opening formed therein from a first surface to a second surface. The sensing device may include a first conductive layer at the first surface, a second conductive layer at the second surface, a segmented sensor layer between the first and second conductive layers, and first and second dielectric layers positioned on opposite surfaces of the segmented sensor layer that insulate the segmented sensor layer from the first and second conductive layers. The segmented sensor layer may include multiple segments positioned around the periphery of the opening. The system may also include circuit elements coupled to each of the multiple segments of the segmented sensor layer. In some examples, the circuit elements include one or more transimpedance amplifiers. The system may also include a processor and a non-transitory computer-readable medium having stored thereon instructions that, when executed by the processor, cause the processor to perform operations including receiving, from one or more circuit elements coupled to the segmented sensor layer, a plurality of measurements corresponding to induced currents passing through segments of the segmented sensor layer when a charged droplet passes through an aperture, and determining a position of the charged droplet based on the measurements.

[0024] In another example, a system for detecting charged droplets from a charged droplet generator may include a control device, the control device including a segmented conductive layer having an aperture formed therein. The segmented conductive layer may include multiple segments positioned around the periphery of the aperture. The system may also include a voltage controller coupled to each of the multiple segments of the segmented conductive layer. In some examples, the voltage controller may be driven to generate an electric potential in each of the segmented conductive layer to establish an electric field at the aperture. The system may optionally include a processor and a non-transitory computer-readable medium having stored instructions that, when executed by the processor, cause the processor to perform operations including applying a set of control voltages to the multiple segments using the voltage controller to control the trajectory of the charged droplets as they pass through the aperture. The set of control voltages may be generated, for example, based on the determined position or velocity of the charged droplets. The system may optionally include a feedforward circuit in which an induced current sensed as the charged droplets pass through a segment of the segmented sensor layer, or a signal based on or proportional to the induced current, is fed to a voltage controller to apply control voltages to the segmented control layer to control the trajectory of the charged droplets as they pass through the aperture. The sets of control voltages may be time-adjusted (e.g., time-delayed or time-shifted), and / or magnitude-adjusted and / or oppositely polarized.

[0025] In another aspect, methods are described herein, such as methods for detecting or controlling charged droplets from a droplet generator or the like. In some examples, the methods may be implemented by or using the systems described herein. In some examples, the methods of this aspect may include positioning a charged droplet detector and / or a charged droplet controller between a droplet generator and a target and directing charged droplets from the droplet generator toward the target and through an aperture in the charged droplet detector and / or the charged droplet controller. The methods of this aspect may include analyzing a voltage signal generated by the charged droplet detector as the charged droplet passes through the aperture to determine the position of the charged droplet. The methods of this aspect may include applying a voltage to be applied to a segment of a segmented control layer to alter the trajectory of the charged droplet, such as by generating a voltage, based on an induced current determined as the charged droplet passes through the aperture of a sensing device. Other examples of this aspect include corresponding devices and systems, each configured to perform the actions of the method. Optionally, methods or portions of the disclosed methods may be implemented during execution of processor-executable instructions.

[0026] In another aspect, described herein are methods for adjusting ejection parameters based on monitored charged droplets in an acoustic droplet ejection system. In some examples, the methods are implemented using the systems described herein, including the acoustic droplet ejection system, sensing element, and other systems described herein. The method may include applying an acoustic signal to a fluid using an acoustic droplet ejection system coupled to a reservoir to eject a first droplet from the reservoir toward a target through an aperture of a charged droplet detector. The method may also include determining that the acoustic signal caused the ejection of a satellite droplet based on measuring a value corresponding to an induced current passing through the charged droplet detector. The method may further include adjusting parameters of the acoustic droplet ejection system based on the determination to prevent or reduce the ejection of satellite droplets in subsequent ejections. In some examples, methods or portions of the disclosed methods may be implemented during execution of processor-executable instructions. [Brief explanation of the drawings]

[0027] A further understanding of the nature and advantages of various examples may be realized by reference to the following figures, in which like components or features may have the same reference labels.

[0028] [Figure 1] FIG. 1 illustrates a droplet generator including a charged droplet management device according to at least some examples.

[0029] [Figure 2] FIG. 2 illustrates a droplet generator including a charged droplet detector and a charged droplet controller according to at least some examples.

[0030] [Figure 3] FIG. 3 illustrates an exploded view of a conductive layer of a charged drop detector, according to at least some examples.

[0031] [Figure 4] FIG. 4 illustrates a side view of a charged drop detector according to at least some examples.

[0032] [Figure 5] FIG. 5 illustrates a top plan view of a segmented conductive layer of a charged drop detector, according to at least some examples.

[0033] [Figure 6] FIG. 6 illustrates a cross-sectional view of a charged drop detector showing electrical connections of conductive layers according to at least some examples.

[0034] [Figure 7] FIG. 7 illustrates an exploded view of the layers of a charged droplet controller according to at least some examples.

[0035] [Figure 8] FIG. 8 illustrates a side view of a charged droplet controller according to at least some examples.

[0036] [Figure 9] FIG. 9 illustrates a top plan view of a segmented conductive layer of a charged droplet controller according to at least some examples.

[0037] [Figure 10] FIG. 10 illustrates a cross-sectional view of a charged droplet controller showing electrical connections of conductive layers according to at least some examples.

[0038] [Figure 11] FIG. 11 illustrates a chart showing differential current from opposing segments of a segmented conductive layer for different droplet displacement locations along an axis between the opposing segments, according to at least some examples.

[0039] [Figure 12] FIG. 12 illustrates a chart showing current from segments of a segmented conductive layer resulting from a charged droplet traveling through an aperture, according to at least some examples.

[0040] [Figure 13] FIG. 13 illustrates a voltage signal associated with the output from a transimpedance amplifier in an example of charged droplet placement within an aperture, according to at least some examples.

[0041] [Figure 14] FIG. 14 illustrates a voltage signal output indicative of a detector signal for a droplet traveling through an aperture, according to at least some examples.

[0042] [Figure 15] FIG. 15 illustrates a representation of the location of the droplet of FIG. 14 according to at least some examples.

[0043] [Figure 16]FIG. 16 illustrates voltage signal outputs indicative of detector signals for main and satellite droplets traveling through an aperture according to at least some examples.

[0044] [Figure 17] FIG. 17 illustrates a representation of the locations of the main and satellite droplets of FIG. 16 according to at least some examples.

[0045] [Figure 18] FIG. 18 illustrates a flowchart showing a process for detecting charged droplets ejected from a droplet generator, according to at least some examples.

[0046] [Figure 19] FIG. 19 illustrates a top plan view of a conductive layer of a charged droplet controller according to at least some examples.

[0047] [Figure 20] Figures 20, 21, and 22 illustrate the relative positions of charged droplets as measured by two charged droplet detectors on opposite sides of the charged droplet controller during steering of the charged droplets by application of different voltage differences between sections of the charged droplet controller. [Figure 21] Figures 20, 21, and 22 illustrate the relative positions of charged droplets as measured by two charged droplet detectors on opposite sides of the charged droplet controller during steering of the charged droplets by application of different voltage differences between sections of the charged droplet controller. [Figure 22] Figures 20, 21, and 22 illustrate the relative positions of charged droplets as measured by two charged droplet detectors on opposite sides of the charged droplet controller during steering of the charged droplets by application of different voltage differences between sections of the charged droplet controller.

[0048] [Figure 23] FIG. 23 illustrates a flowchart showing a process for controlling charged droplets ejected from a droplet generator according to at least some examples.

[0049] [Figure 24] FIG. 24 illustrates a flowchart showing a process for detecting and controlling charged droplets ejected from a droplet generator using a feedback mechanism according to at least some examples.

[0050] [Figure 25A] FIG. 25A illustrates signals from four electrodes that are smoothed using a high frequency filter according to at least some examples.

[0051] [Figure 25B] FIG. 25B illustrates polarity reversal of a signal that may be amplified and introduced into a trajectory correction electrode, according to at least some examples.

[0052] [Figure 26] FIG. 26 illustrates an example block diagram of a computing device according to some examples.

[0053] [Figure 27] FIG. 27 provides an overview of an exemplary charged droplet ejection, detection, and control system according to some examples. DETAILED DESCRIPTION OF THE INVENTION

[0054] The present disclosure describes devices, systems, and methods for real-time detection, monitoring, and / or control of charged droplets using compact, low-cost devices. Numerous benefits can be achieved by the disclosed systems and methods, including horizontal position detection (e.g., along the X and Y axes) of charged droplets, droplet velocity measurement, satellite droplet detection, droplet charge measurement, droplet counting, droplet tracking, and droplet trajectory control. In some examples, the devices, systems, and methods described herein may be useful for diagnostic measurements for droplet generator alignment, detection of misdirection in ejected droplet trajectories, and / or correction of misdirected ejected droplets. Advantageously, such aspects can be implemented in real time during droplet generation and used to provide feedback to modify or adjust system components, alignment, ejection parameters, etc. Precision droplet placement may also enable drop-on-drop chemistry or the generation of microarrays at the bottom of wells. Currently, the inherent distribution of droplet trajectories makes these tasks difficult, but the ability to correct the placement of each droplet during transport via the techniques described herein opens up these new areas of research.

[0055] In some examples, the charge carried by a droplet (droplet charge) can be related to the volume of a particular source fluid, thereby allowing measurement of droplet charge over several droplets to predict and / or determine droplet volume. While typical systems rely on manual calibration and / or large, expensive optical tracking systems, the devices, systems, and methods provided herein enable real-time tracking and / or control of charged droplets using a compact, low-cost system. The real-time measurements enabled herein provide increased manufacturing workflow efficiency and rapid optimization of droplet generators, such as for calibration of acoustic droplet ejection systems. The disclosed systems and methods can also enable efficient coupling and precise alignment of droplet generators with the inlet of a secondary device, such as a mass spectrometer or other analytical system. The devices, systems, and methods described herein are particularly useful for real-time tracking, e.g., to confirm droplet placement in a mass spectrometer or other analytical system during sample placement for analysis. The devices, systems, and methods described herein are also useful for controlling droplet trajectories in real time, optionally using a feedback mechanism, in which droplet position and / or trajectory is determined and droplet trajectory is adjusted, for example, to optimize droplet placement in a mass spectrometer or other analytical system during sample placement for analysis.

[0056] Droplet generation can include processes such as acoustic droplet ejection, in which droplets are acoustically actuated from a fluid reservoir and travel toward a target surface or location, although the present disclosure is not limited to droplet generation using acoustic droplet ejection systems. Other systems, such as pressure-based, inkjet-type, and / or microfluidic-type droplet generators or ejection systems, can be used. In some embodiments, for acoustic droplet ejection, acoustic energy can be directed toward the fluid meniscus of a fluid contained within a reservoir of a sample container (e.g., a well in a microplate, a fluid sample tube, a microplate, a microfluidic device), or toward an inlet to an analytical instrument, system, or device (including a mass spectrometer or other instrument for analyzing chemical composition, genome content, genome location, particle sizer, bodily fluid, cell analysis (e.g., a cytometer, a hemocytometer), etc.). In some embodiments, the droplet generator can be oriented so that the droplets travel vertically upward toward the target surface or location. Although droplets are described herein as moving upward, droplets can be transported in other directions, such as downward and / or sideways, in addition to upward, so long as the systems and methods described herein are implemented. In acoustic droplet ejection systems, due at least in part to static effects (e.g., tilted fluid meniscus, electrostatic charges in the well plastic) and dynamic effects (e.g., capillary waves in the well), droplet trajectories from the ejecting fluid meniscus to the target surface can be misdirected from their intended path, resulting in droplet misdirection at the target surface / destination. Similar misdirection can occur in other droplet generation systems due to static and / or dynamic effects. The systems and methods described herein enable real-time measurement of droplet misdirection, allowing for monitoring and, optionally, mitigation of droplet misdirection, such as by implementing a droplet control scheme in which droplet trajectories are adjusted.

[0057] When the target is a destination microplate well and multiple droplets are being transferred, it may be desirable for all droplets to fuse and coalesce into a single larger droplet at the target. However, in some cases, droplets ejected by a droplet generator may arrive at the target location within a certain tolerance. For example, a particular application may impose a placement tolerance, such as within a dimension that is a fraction of the droplet diameter (e.g., within 100%, 75%, 50%, 25%, 10%, or 5% of the droplet diameter). Such a placement tolerance may ensure, for example, that a droplet arrives on the target or that different droplets coalesce upon reaching the target. In some cases, a droplet may arrive off-target by no more than about 200% of the droplet diameter (e.g., a 2.5 nL droplet with a diameter of 168 microns may arrive 400 microns off-target). In preferred cases, droplets consistently land at or within a distance from the target location that is no greater than 125% of the droplet diameter, with fewer than one droplet per 1,000 landing more than 125% of the droplet diameter from the target location. After the first droplet, subsequent droplets directed to the target location may desirably fuse, coalesce, and mix into a single larger droplet. Ideally, there should be no off-target droplets that land separately from the main droplet, no scattering, and no spraying. Droplet placement on the target can tolerate not only the widest possible range of initial velocity and direction at droplet formation, but also variation along the droplet flight path. In some examples, the target can be a well in a microplate, a microfluidic device, or an inlet or orifice associated with an analytical instrument. The droplets can be sized to properly reach the target without colliding with the sides or walls of the inlet or orifice. For example, the orifice may have a diameter that is 130% or greater than the diameter of the droplet, such as greater than or about 150%, 200%, 250%, 300%, 350%, 400%, 450%, 500% of the diameter of the droplet, or about 150%, 200%, 250%, 300%, 350%, 400%, 450%, 500%, or about 130% to about 1,000%.

[0058] In some cases, the target may be associated with a mass spectrometer (e.g., the open port probe (OPP) interface of a mass spectrometer) or other analytical instrument or system. The opening of the OPP may be defined, at least in part, by the coaxial arrangement (along the capillary axis) of the capillary and the housing. In some such cases, a droplet placement tolerance of less than or about 125% of the droplet diameter from the vortex core (capillary axis) is a desirable feature to ensure accurate droplet placement within the OPP. In these cases, droplet placement that exceeds 125% of the droplet diameter from the target position may result in lower ion counts and higher charge volumes in the mass spectrometer. Droplet placement that exceeds or is about 200% or 250% of the droplet diameter may result in missing ion count peaks.

[0059] According to examples described herein, the charged droplet management system can be located between the target and the droplet generator, such as between the target and the source well of an acoustic droplet ejection system. The charged droplet management system can include an aperture that can be aligned with the ejection axis of the droplet generator (e.g., the transducer axis of the ejection system) so that droplets ejected by the droplet generator pass through the aperture toward the target. The charged droplet management system can include one or both of a sensing or detector component and / or a control component. In either case, the charged droplet management system can include several segmented electrodes surrounding the aperture.

[0060] For use as a charged droplet detector, when a charged droplet passes through the aperture, a current is induced in each segmented electrode and detected using circuit elements to convert each segmented current into a corresponding output value. The output value may correspond to the induced current or a voltage value representing (based on, or proportional to) the induced current. In some examples, the circuit elements may include one or more transimpedance amplifiers. While the description herein may refer to transimpedance amplifiers, other suitable circuit elements may be implemented in place of transimpedance amplifiers. Because the sensor components and aperture geometry are known and predefined, the induced current can be modeled and determined. For example, the Ramo-Shockley theorem may be utilized to determine droplet charge, velocity, and / or trajectory based on the current induced in the segmented electrodes. In particular, the sum of all values, such as the induced current (and therefore the transimpedance amplifier voltage), may be directly related to droplet charge and velocity. Additionally, the difference in signals from opposing segments around the aperture may be used to determine the lateral position of each droplet as it passes through the aperture.

[0061] For use as a charged droplet controller, a voltage can be applied to each segmented electrode to generate an electric field that exerts a force on the charged droplet and adjusts its trajectory as the charged droplet passes through the aperture. Various configurations of segmented electrodes can be used, such as to enable precise adjustment of the charged droplet trajectory across two axes (e.g., X and Y axes). The voltage can be applied by one or more voltage controllers or by other suitable components that can be implemented as (or instead of) a voltage controller.

[0062] FIG. 1 illustrates a system 111 having a charged droplet management device 110, according to at least some examples. As with all figures referenced herein, FIG. 1 is not to scale, and certain dimensions may be exaggerated for clarity of presentation. System 111 is shown including a droplet generator 101 for generating charged droplets. In FIG. 1, droplet generator 101 is depicted as an acoustic droplet ejection system, but such a configuration is not limited, and other droplet generators may be used without departing from aspects described herein. System 111 illustrated in FIG. 1 is configured to receive a sample vessel 112, which is optionally separate from system 111 and may be a consumable product having one or more reservoirs (e.g., a microplate, a fluid sample tube, or a well plate). For example, sample vessel 112 includes multiple reservoirs, i.e., two or more reservoirs, with a first reservoir at 113 and a second reservoir at 115, each adapted to contain a fluid having a fluid surface, e.g., a first fluid 114 and a second fluid 116 having fluid surfaces shown at 117 and 119, respectively. First fluid 114 and second fluid 116 can be the same or different. In some examples, sample vessel 112 includes only a single reservoir, and the systems and methods herein may enable droplet ejection from a single reservoir, tracking of droplet misdirection, and verification of successful droplet control, although systems and methods in which droplets may be ejected, tracked, and / or controlled from multiple reservoirs are also contemplated. As shown, the reservoirs are of substantially identical structure and substantially acoustically indistinguishable, although identical structure is not a requirement. Although the reservoirs are shown as separate, removable components, they can be fixed within a plate or other substrate if desired. For example, multiple reservoirs can comprise individual wells within a well plate, which can, but need not, be arranged in an array. Each of reservoirs 113 and 115 is preferably axisymmetric as shown, having vertical walls 121 and 123 extending upward from reservoir bases 125 and 127, respectively, and terminating in openings 129 and 131.The material and thickness of each reservoir base may be such that acoustic radiation may be transmitted through the base and into the fluid contained within the reservoir.

[0063] System 111 includes acoustic ejector 133 comprising an acoustic radiation generator 135 for generating acoustic radiation and a focusing device 137 that focuses the acoustic radiation within the fluid near the fluid surface from which droplets are to be ejected. As shown in FIG. 1 , focusing device 137 may comprise a single solid piece having a concave surface 139 for focusing the acoustic radiation, although focusing device 137 may be constructed in other manners as discussed below. Acoustic ejector 133 is thus adapted to eject droplets of fluid from each of fluid surfaces 117 and 119 by generating and focusing acoustic radiation when acoustically coupled to reservoir wells 113 and 115 (and thus to first fluid 114 and second fluid 116), respectively. Acoustic radiation generator 135 and focusing device 137 may function as a single unit controlled by a single controller, or they may be controlled independently, depending on the desired performance of the device. Typically, single ejector designs are preferred over multiple ejector designs because droplet placement accuracy and consistency in droplet size and velocity are more easily achieved with a single ejector, although the present disclosure also contemplates that multiple ejectors may be used.

[0064] It should be understood that any of a variety of focusing devices 137 may be employed in conjunction with the present invention. For example, one or more curved surfaces may be used to direct acoustic radiation to a focal point near the fluid surface. One such technique is described in U.S. Pat. No. 4,308,547 to Lovelady et al. Focusing devices 137 with curved surfaces are incorporated into the structure of commercially available acoustic transducers, such as those manufactured by OLYMPUS CORP. (Waltham, Mass.). Additionally, Fresnel lenses for directing acoustic energy to a predetermined focal distance from an object plane are known in the art. See, for example, U.S. Pat. No. 5,041,849 to Quate et al. Fresnel lenses may have a radial phase profile that diffracts a substantial portion of acoustic energy into predetermined diffraction orders at diffraction angles that vary radially relative to the lens. The diffraction angles may be selected to focus the acoustic energy in the diffraction orders onto a desired object plane.

[0065] In operation, reservoir wells 113 and 115 of the device are each filled with first fluid 114 and second fluid 116, respectively, as shown in FIG. 1. Acoustic ejector 133 can be positioned using ejector positioner 143, which can include, for example, an actuator capable of moving acoustic ejector 133 to a desired location to achieve acoustic coupling between the ejector and the reservoir through acoustic coupling medium 141. In FIG. 1, substrate 145 is shown positioned above and proximate first reservoir well 113, with one surface of the substrate facing the reservoir and positioned substantially parallel to or opposite fluid surface 117 of first fluid 114 in the reservoir. In some embodiments, substrate 145 can be a sample container (e.g., a microplate, a sample tube) that includes a target area for droplet ejection. Once the ejector, reservoirs, and substrate are properly aligned, acoustic radiation generator 135 is activated to produce acoustic radiation, which is directed by focusing device 137 to a focal point 147 at or near fluid surface 117 of the first reservoir. As a result, droplets 149 are ejected from fluid surface 117 onto designated sites on the underside surface of substrate 145, including wells 155. In some cases, surface tension or capillary forces may assist (or cause) the ejected droplets to be retained on the substrate surface. Although not shown in FIG. 1 , the present disclosure contemplates that the interface of an analytical device, system, or instrument, such as a mass spectrometer (e.g., OPP), or any other suitable target, may replace substrate 145.

[0066] The system 111 includes a substrate positioning device 150 that can be adjusted to reposition the substrate 145 over the reservoir 115 to receive droplets from the reservoir 115 at a second designated site. For example, the acoustic ejector 133 can be repositioned by the ejector positioner 143 below the reservoir 115 in acoustically coupled relationship with the reservoir 115 by the acoustic coupling medium 141. Once properly aligned, the acoustic radiation generator 135 of the acoustic ejector 133 can be activated to produce acoustic radiation, which is then directed by the focusing device 137 to a focal point 148 at or near the fluid surface 119 of the second fluid 116, thereby ejecting additional droplets onto the substrate 145 in the well 157. It should be understood that such operation is illustrative of how the device may be used to eject multiple fluids from reservoirs to form a pattern (e.g., an array) on substrate 145. It should also be understood that the device may be adapted to eject multiple droplets from one or more reservoirs onto the same site on substrate 145.

[0067] 1 illustrates a particular configuration, the present disclosure contemplates any suitable configuration to which the disclosed concepts may be readily adapted as appropriate. For example, the 111 system may be oriented in different ways (e.g., acoustic ejector 133 positioned above substrate 145 so that droplets are ejected downward, or acoustic ejector 133 positioned to the side of substrate 145 so that droplets are ejected sideways).

[0068] As shown, system 111 includes a charged droplet management device 110 that is capable of sensing, detecting, characterizing, deflecting, and / or manipulating the velocity or direction of charged droplets passing therethrough. In some embodiments, charged droplet management device 110 may include one or several conductive layers, as described further below. In some embodiments, system 111 may apply (or impart) an electric charge to droplets 149 prior to, during, or after ejection. Thus, droplets 149 may carry a net electric charge. A net electric charge may be induced in the droplets by applying a voltage to one or more of the layers of charged droplet management device 110. The voltage may generate an electric field at the fluid meniscus, which induces a net electric charge in the ejected droplets. In some examples, the natural electric charge of the droplets may be measured without an external electric field. Such a net charge can be imparted, for example, by directly applying a voltage or charge (e.g., a 1.5 kV bias) to the fluid 114 of FIG. 1, by passing the droplets through an additional biased conductive layer held at a reference voltage (e.g., a high voltage) positioned between the reservoir and the charged droplet management device 110, or by applying a voltage bias to the entire charged droplet management device 110 or to a portion of the charged droplet management device 110.

[0069] The charge imparted to charged droplets can be positive or negative, depending on the voltage and / or electric field at the fluid 114 or meniscus. Optionally, the polarity of the charge imparted to the droplets can be changed, such as from positive to negative or from negative to positive. The polarity can be altered by adjusting the voltage and / or electric field at the fluid or meniscus during droplet generation, such as by switching the polarity of the voltage. The polarity can be altered periodically or aperiodically. In some cases, changing the polarity during droplet generation can reduce charge accumulation on the target (e.g., substrate 145) because negatively charged droplets can offset accumulated positive charge previously developed on the target; and / or because positively charged droplets can offset accumulated negative charge previously developed on the target. With regard to sensing and control of charged droplets by the charged droplet management device 110, the operation of using appropriate voltages for detecting or controlling positively or negatively charged droplets can be synchronized with the polarity of the droplets being generated. For use in directing charged droplets to a mass spectrometer or other analytical system, the operation of the mass spectrometer or other analytical system for analysis of positively or negatively charged droplets can be synchronized with the polarity of the droplets being generated.

[0070] The charged droplet management device 110 includes an opening 109 through which droplets 149 travel from the first reservoir well 113 to well 155. The opening 109 is aligned with the transducer axis 118 of the acoustic ejector 133. Without limitation, the opening of the charged droplet management device may have a diameter of 1 mm to 5 mm or greater, such as 1 mm to 1.5 mm, 1.5 mm to 2 mm, 2 mm to 2.5 mm, 2.5 mm to 3 mm, 3 mm to 3.5 mm, 3.5 mm to 4 mm, 4 mm to 4.5 mm, or 4.5 mm to 5 mm. In some examples, the opening of the charged droplet management device may have a diameter larger than the diameter of the droplet, such as when the opening has a diameter that is greater than, or about 120% of, the diameter of the droplet, or less than about 500% of the diameter of the droplet. Without limitation, the apertures may have a diameter that is greater than or about 120%, 130%, 140%, 150%, 160%, 170%, 180%, 190%, 200%, 225%, 250%, 275%, 300%, 325%, 350%, 375%, 400%, 425%, 450%, 475%, or 500% of the diameter of the droplet. In some cases, the aperture diameter may be greater than 500% of the diameter of the droplet, for example, the aperture diameter may be as great as or greater than 3,000% or 5,000% of the diameter of the droplet.

[0071] In some examples, the charged droplet management device 110 may be positioned parallel to or at an angle to the surface of the first reservoir well 113. In some examples, the charged droplet management device 110 may be positioned obliquely at an angle to the first reservoir well 113.

[0072] The charged droplet management device 110 may be used for sensing, detecting, or characterizing charged droplets in a configuration referred to herein as a charged droplet detector or charged droplet sensor. Alternatively, or in addition, the charged droplet management device 110 may be used to control the direction, velocity, or trajectory of charged droplets in a configuration referred to herein as a charged droplet controller. The charged droplet detector or charged droplet sensor may advantageously be useful for identifying the position of charged droplets passing through the aperture 109, such as for determining the lateral (e.g., X, Y) position of the charged droplet. Additionally, the charged droplet detector may be used to determine velocity, droplet timing (e.g., arrival at the aperture), total droplet charge, and / or the presence of one or more charged satellite droplets. The charged droplet controller can be advantageously useful for adjusting the charged droplet trajectory, such as by applying a force (e.g., an impulse force) to steer the charged droplet (e.g., by generating a deflection in a lateral direction).

[0073] A feedback system may be included with or as part of the charged droplet management device 110 to enable the charged droplet detector to determine the lateral position of the charged droplet and provide a steering signal (such as a voltage signal determined based on the lateral position of the charged droplet) to the charged droplet controller. In this manner, the charged droplet management device 110 can identify misdirected charged droplets and adjust their trajectories so that they are received at their intended targets. For example, the charged droplet detector component of the charged droplet management device 110 can be used to generate current and / or voltage waveforms (described in further detail below) upon passage of charged droplets therethrough and provide such waveforms to a signal processing component for extracting the position of the charged droplet at the charged droplet detector. The position of the charged droplet detector can be further analyzed and / or used, such as by signal processing or other processing components, to determine the appropriate steering voltage to apply to the charged droplet controller component of the charged droplet management device 110. In some examples, the steering voltage may be determined using a look-up table or function in which the position is provided as an input and the steering voltage is provided as an output.

[0074] In some examples, both a charged droplet detector and a charged droplet controller may be used, and they may be integrated into a single charged droplet management device or as separate components. Figure 2 shows an exemplary system 211, which may be the same as or different from system 111 shown in Figure 1, including a charged droplet detector 210A and a charged droplet controller 210B in addition to the other components shown in system 111 (including droplet generator 101 and substrate 145). In the configuration shown, charged droplet detector 210A is positioned closer to droplet generator 101, charged droplet controller 210B is positioned closer to substrate 145, and their openings 209A and 209B, respectively, are positioned relative to each other such that droplet 249 passes through both openings 209A and 209B as droplet 249 travels along axis 218 toward substrate 145. Such a configuration is not intended to be limiting. For example, charged droplet controller 210B may instead be positioned closer to droplet generator 101, and charged droplet detector 210A may be positioned closer to substrate 145. In some examples, only charged droplet detector 210A is used, and charged droplet controller 210B is not present. In other examples, only charged droplet controller 210B is used, and charged droplet detector 210A is not present. Optionally, multiple charged droplet detectors 210A may be used. Optionally, multiple charged droplet controllers 210B may be used. In some examples, two charged droplet detectors 210A may be used with a single charged droplet controller 210B between them. Such a configuration may be useful in some examples to detect charged droplet position with a first charged droplet detector, correct charged droplet trajectory with a charged droplet controller, and detect charged droplet position with a second charged droplet detector after the trajectory correction. Any suitable spacing or distance between components of the charged droplet management device (eg, between the charged droplet detector 210A and the charged droplet controller 210B) may be used.In some examples, the spacing between charged drop detector 210A and charged drop controller 210B can be between 25% and 400% of the diameter of aperture 209A and / or aperture 209B. In some examples, the spacing between components of a charged droplet management system (e.g., charged droplet detector and / or charged droplet controller) may be 0.1 mm to 10 mm or greater, such as 0.1 mm to 0.5 mm, 0.5 mm to 1 mm, 1 mm to 1.5 mm, 1.5 mm to 2 mm, 2 mm to 2.5 mm, 2.5 mm to 3 mm, 3 mm to 3.5 mm, 3.5 mm to 4 mm, 4 mm to 4.5 mm, 4.5 mm to 5 mm, 5 mm to 5.5 mm, 5.5 mm to 6 mm, 6 mm to 6.5 mm, 6.5 mm to 7 mm, 7 mm to 7.5 mm, 7.5 mm to 8 mm, 8 mm to 8.5 mm, 8.5 mm to 9 mm, 9 mm to 9.5 mm, or 9.5 mm to 10 mm. In some examples, the spacing between components of a charged droplet management system can be as large as or larger than the diameter of the droplet, such as when the spacing is greater than, or about, 100% of the diameter of the droplet, or greater than 100% of the diameter of the droplet. Without limitation, the spacing between components of a charged droplet management system can be 50%, 100%, 150%, 200%, 250%, 300%, 350%, 400%, 450%, 500%, 550%, 600%, 650%, 700%, 750%, 800%, 850%, 900%, 950%, 1,000%, 1,500%, 2,000%, 3,000%, 4,000%, or greater than the diameter of the droplet. is greater than 5,000%, or is about 50%, 100%, 150%, 200%, 250%, 300%, 350%, 400%, 450%, 500%, 550%, 600%, 650%, 700%, 750%, 800%, 850%, 900%, 950%, 1,000%, 1,500%, 2,000%, 3,000%, 4,000%, or 5,000% or more.

[0075] With respect to sensing, detecting, or characterizing charged droplets using a charged droplet detector, as charged droplet 149 or 249 travels through aperture 109 or 209A, a current is induced in the conductive layer of the charged droplet detector. The magnitude of the induced current can be related to the relative position of the charged droplet from the detector plate or a segment of the detector plate (such as segments 366A, 366B, 366C, and 366D shown in FIG. 3 or segments 566A, 566B, 566C, and 566D shown in FIG. 5). For example, a segment producing a larger induced current may be relatively closer to droplet 149 than other segments, and by determining the difference between the induced currents of different segments, a weighting or scaling factor can be generated that can be used to identify the two-dimensional position (e.g., XY) of droplet 149 as it passes through aperture 109 and past a segment of the detector plate.

[0076] 2, charged droplet 249 has a trajectory (e.g., in the absence of influence by charged droplet controller 209B) such that it arrives at well 155 that is shifted from axis 218, which represents the intended target position for charged droplet 249. The lateral deviation of the charged droplet from axis 218 at aperture 209A can be determined using charged droplet detector 210A, such as by measuring an induced current in charged droplet detector 210A. In some examples, the lateral deviation can be used to determine a voltage to apply to components of charged droplet controller 210B to generate an electric field at aperture 209B that can deflect the trajectory of charged droplet 249 back toward the target position in well 155. In another example, the induced current in the charged droplet detector can be used to determine and / or directly generate a voltage to be applied to components of the charged droplet controller 210B to generate an electric field in the opening 209B that can deflect the trajectory of the charged droplet 249 back toward the target position in the well 155.

[0077] The voltages applied in charged droplet controller 210B, such as in each of the sections, may be controlled using one or more voltage controllers or voltage generators, which may be incorporated as part of charged droplet controller 210B or may be provided by external circuitry. For example, a voltage controller may be electrically coupled to each of the sections of charged droplet controller 210B.

[0078] In operation, charged droplets 249 may travel at high speed from charged droplet generator 101 toward well 255. Due to the combination of the velocity of the charged droplets and the spacing between charged droplet detector 210A and charged droplet controller 210B, there may not be enough time to precisely calculate the voltage to be applied by charging voltage controller 210B; however, if the induced current is used directly to apply or generate the voltage to be applied by charging voltage controller 210B, the voltage can be generated without the need to take time to first calculate the voltage. Therefore, the voltage may need to be applied to charging voltage controller 210B as soon as charged droplet 249 passes through aperture 209A.

[0079] In embodiments, adequate spacing may exist between the charged droplet detector 210A and the charged droplet controller 210B, so that a voltage need not be applied immediately. However, the spacing may still not be sufficient for extended calculations, if calculations are required. In embodiments in which the induced current is used directly to apply or generate the voltage to be applied by the charging voltage controller 210B, a delay time may be determined, and the application of the voltage to the charged droplet controller 210B may be adjusted to account for when the charged droplet 249 will pass through the opening 209B of the charged droplet controller 210B. The delay time may be determined by the magnitude of the velocity of the charged droplet 249, which may be similar to the velocity of the previous charged droplet, and the magnitude of the spacing (e.g., distance) between the charged droplet detector 210A and the charged droplet controller 210B. Optionally, filtering, polarity reversal, and / or smoothing may be applied during the generation of the voltage from the induced current.

[0080] Although only one charged droplet detector 210A and one charged droplet controller 210B are depicted diagrammatically, it is envisioned that system 211 may include multiple charged droplet detectors 210A and / or charged droplet controllers 210B. For example, a second charged droplet detector may be positioned above charged droplet controller 210B to provide feedback regarding the trajectory of charged droplets 249 after passing through charged droplet controller 210B. Similarly, a second charged droplet controller may be positioned above the second charged droplet detector to apply additional voltage to charged particles 249, as previously described with respect to charged droplet controller 210B. Any number of charged droplet detectors and / or charged droplet controllers is envisioned by the present disclosure.

[0081] FIG. 3 illustrates an exploded view of the conductive layers of a charged droplet detector 310, according to at least some examples. The charged droplet detector 310 may correspond to one implementation of the charged droplet management device 110 of FIG. 1. The charged droplet detector 310 includes a first conductive layer 360, a second conductive layer 362, and a sensor layer 361. When a charged droplet 349 passes through an aperture (such as an aperture comprising or including apertures 363, 364, and 365) of the charged droplet detector 310, an induced current is generated in each section of the sensor layer 361 (e.g., sections 366A, 366B, 366C, and 366D of FIG. 3). Spacers or insulating regions 307 are positioned between sections 366A, 366B, 366C, and 366D to electrically isolate the sections from one another. The amount of induced current in each segment 366A, 366B, 366C, 366D may depend on the lateral position of the charged droplet 349 as it passes through the aperture 364 and the relative sizes of the segments. This induced current in each of the segments may be measured using one or more circuit elements. For example, a transimpedance amplifier may be connected to each segment, and such transimpedance amplifier may produce a voltage output from each segment that may be measured. As one skilled in the art will recognize, such a voltage output may be directly related to the induced current in the detector segment through the feedback resistance of the transimpedance amplifier by application of Ohm's Law. Thus, this disclosure contemplates that a charged droplet detector or associated system may measure voltage, current, or any other measurement from which induced current may be derived. While this disclosure contemplates that any suitable voltage / current / charge measurement circuit element may be used, the example of using a transimpedance amplifier to measure the output voltage is provided as an example.

[0082] A droplet passing through the exact center of aperture 364 will induce equal currents in all four segments 366A, 366B, 366C, and 366D, and therefore equal voltages at the outputs of each of the transimpedance amplifiers connected to the segments, if the segments are equal in size. A droplet that is misdirected from the aperture center and passes closer to one segment than another will induce larger currents in the segments the droplet passes closer to and smaller currents in the segments the droplet passes farther away as the droplet travels through the device. These differences in induced currents can be clearly modeled by those skilled in the art, for example, using the Ramo-Shockley theorem. Similarly, differences in induced currents can be clearly modeled by those skilled in the art for unequal segments 366A, 366B, 366C, and 366D by accounting for those differences in size in the model. By measuring the difference between the signals detected from the various segments and appropriately normalizing or weighting (such as by the total sum signal from all sensors, and / or by the aperture perimeter occupied by each segment, or by some more complex method determined from the mode), the lateral location of the droplet as it passes through the aperture 364 of the charged droplet detector 310 can be extracted. From the total sum signal from all sensors, with a small correction due to any lateral misalignment of the droplet from the aperture center, as measured using the differential signal, the total droplet charge, or a signal based on (or proportional to) the total droplet charge, can be extracted.

[0083] In some examples, by measuring the difference in measured current between signals detected from opposing sections, e.g., sections facing each other along the X and / or Y axes (see, e.g., opposing sections 366A and 366C, opposing sections 366B and 366D in FIG. 3), and appropriately normalizing or weighting (such as by the total signal from all sections of sensor layer 361, or using weighting factors characteristic of the perimeter occupied by each section, or characteristic of other aspects or behavior of the sections), the lateral (e.g., X, Y) location of the droplet as it passes through aperture 364 of charged droplet detector 310 can be extracted. In some cases, the drop charge can also be extracted by using the total sum signal from all segments, with a slight correction due to any lateral misalignment of the drop from the aperture center, as measured using the differential signal. Measurement of both the drop lateral position and drop charge is fundamental and may not require any calibration of the sensor other than knowledge of its geometry and the current-to-voltage conversion characteristics of the transimpedance amplifier, although in some instances calibration may be used.

[0084] In some examples, an additional sensor layer 361 may be stacked together perpendicular to the axis of travel of the droplet 349 to track the droplet as it passes through the aperture of the sensor device 310. While the examples described herein focus on determining or inferring the induced current by measuring the voltage from a transimpedance amplifier, the present disclosure contemplates measuring any suitable value from which the induced current may be determined.

[0085] 4 illustrates a side view of charged drop detector 410, which may be different from or the same as components of charged drop management device 110 of FIG. 1 , charged drop detector 210A of FIG. 2 , or charged drop detector 310 of FIG. 3 , according to at least some examples. While layers of charged drop detector 410 are shown, additional layers may be implemented in some examples. In some examples, charged drop detector 410 may be (or may comprise) a printed circuit board including a printed and / or silkscreened top layer 470 and solder mask layers 469 and 471. Conductive layers 460 and 462, as described above with reference to the components of charged drop detector 310 of FIG. 3 , and sensor layer 461 (which is itself a conductive layer) are within the printed circuit of charged drop detector 410. Insulating layers 467 and 468 are positioned between conductive layers 460 and 462 and sensor layer 461 to electrically isolate them from sensor layer 461. All layers define an opening 409 through which charged drop detector 410 passes.

[0086] Insulating layers 467 and 468, conductive layers 460 and 462, and sensor layer 461 may each have any suitable thickness. For example, the insulating layers and / or conductive layers (including the sensor layer) in the charged drop detector may have thicknesses ranging from 0.1 mm to 0.2 mm, 0.2 mm to 0.3 mm, 0.3 mm to 0.4 mm, 0.4 mm to 0.5 mm, 0.5 mm to 0.6 mm, 0.6 mm to 0.7 mm, 0.7 mm to 0.8 mm, 0.8 mm to 0.9 mm, 0.9 mm to 1 mm, 1 mm to 1.1 mm, 1.1 mm to 1.2 mm, and so on. 2mm, 1.2mm~1.3mm, 1.3mm~1.4mm, 1.4mm~1.5mm, 1.5mm~1.6mm, 1.6mm~1.7mm, 1.7mm~1.8mm, 1.8mm ~1.9mm, 1.9mm~2mm, 2mm~2.1mm, 2.1mm~2.2mm, 2.2mm~2.3mm, 2.3mm~2.4mm, 2.4mm~2.5mm, 2.5mm~2 .6mm, 2.6mm~2.7mm, 2.7mm~2.8mm, 2.8mm~2.9mm, 2.9mm~3mm, 3mm~3.1mm, 3.1mm~3.2mm, 3.2mm~3. 3mm, 3.3mm~3.4mm, 3.4mm~3.5mm, 3.5mm~3.6mm, 3.6mm~3.7mm, 3.7mm~3.8mm, 3.8mm~3.9mm, 3.9mm~ The thickness may be 0.1 mm to 5 mm, such as 0.1 mm to 1.0 mm or greater, including 4 mm, 4 mm to 4.1 mm, 4.1 mm to 4.2 mm, 4.2 mm to 4.3 mm, 4.3 mm to 4.4 mm, 4.4 mm to 4.5 mm, 4.5 mm to 4.6 mm, 4.6 mm to 4.7 mm, 4.7 mm to 4.8 mm, 4.8 mm to 4.9 mm, 4.9 mm to 5 mm, etc. Thicknesses for conductive and insulating layers may extend outside these ranges in some cases, and in particular, conductive layers may have thicknesses less than 0.2 mm or less than 0.1 mm. In some examples, thicknesses for conductive or insulating layers may be as large as or larger than the diameter of the droplet, such as when the thickness is greater than, or about, 100% of, or greater than 100% of the diameter of the droplet.Without limitation, the thickness of the conductive or insulating layer may be 50%, 100%, 150%, 200%, 250%, 300%, 350%, 400%, 450%, 500%, 550%, 600%, 650%, 700%, 750%, 800%, 850%, 900%, 950%, 1,000%, 1,500%, 2,000%, 3,000%, 4,000%, or 500% of the diameter of the droplet. ,000%, or about 50%, 100%, 150%, 200%, 250%, 300%, 350%, 400%, 450%, 500%, 550%, 600%, 650%, 700%, 750%, 800%, 850%, 900%, 950%, 1,000%, 1,500%, 2,000%, 3,000%, 4,000%, or 5,000% or more. In some cases, the ratio of the diameter of the opening to the thickness of one or more of the insulating layers may be between 0.25 and 4. In some cases, the ratio of the diameter of the opening to the thickness of one or more of the conductive layers may be between 0.25 and 4. Optionally, the thickness for the conductive layer may be dictated by manufacturing, such as in the case of a charged droplet management device including a printed circuit board in which the copper foil or copper plating thickness may be standardized (e.g., copper layer thickness of about 35 μm, about 70 μm, about 105 μm, or about 140 μm). In some examples, the thickness of each insulating layer is the same, but they may optionally be different. In some examples, the thickness of each conductive layer, including the sensor layer, is the same, but they may optionally be different. In some examples, the thicknesses of the conductive and insulating layers are different from each other, but they may optionally be the same.

[0087] Although the detector of FIG. 4 shows three total electrodes and sensor layers, additional or fewer conductive layers and / or additional sensor layers may be included in some examples. Layers, including conductive layers 460 and 462, sensor layer 461, and other layers, can be arranged in a non-parallel manner, whereby the layers are not aligned along parallel planes, which can be useful for three-dimensional detection of charged droplet position. In some embodiments, sensor layer 461 and conductive layers 460 and 462 are (or comprise) a metal, such as copper. Sensor layer 461 and conductive layers 460 and 462 can have any suitable lateral dimensions, such as between 0.5 cm and 5 cm (e.g., 0.5 cm, 0.6 cm, 0.7 cm, 0.8 cm, 0.9 cm, 1.0 cm, 1.1 cm, 1.2 cm, 1.3 cm, 1.4 cm, 1.5 cm, 2 cm, 2.5 cm, 3 cm, 3.5 cm, 4 cm, 4.5 cm, or 5 cm), although larger or smaller dimensions can be implemented. In some examples, sensor layer 461, or a component of sensor layer 461 (such as a section of sensor layer 461), may have larger lateral dimensions than conductive layers 460 and 462 to provide electrical connection to a transimpedance amplifier. For charged drop sensing, conductive layers 460 and 462 may be electrically coupled to a reference potential, such as ground, while sensor layer 461 is electrically coupled to a charge-sensitive circuit or preamplifier, such as a transimpedance amplifier. The integrating circuitry of the transimpedance amplifier can be used to convert the induced current into a detectable voltage output. Insulating layers 467 and 468 may be formed from a suitable dielectric and / or insulating material, such as a laminate (e.g., as used in some printed circuit boards).

[0088] 5 illustrates a top plan view of a sensor layer 561 of a charged droplet detector, such as the charged droplet detector of charged droplet management device 110 of FIG. 1 , charged droplet detector 210A of FIG. 2 , charged droplet detector 310 of FIG. 3 , or charged droplet detector 410 of FIG. 4 , according to at least some examples. Sensor layer 561, in some embodiments, defines an opening 564, which may be at least a portion of opening 509 of charged droplet detector 510 and may have a diameter of 2 mm. In some examples, the diameter may be greater than or less than 2 mm. Sections 566A, 566B, 566C, and 566D of sensor layer 561 divide the layer into equally sized sections surrounding opening 564, each section optionally providing an equal portion of the perimeter of opening 564, although such a configuration is not intended to be limiting and any suitable size or configuration of sections may be used. Spaces or insulating regions 507 are positioned between segments 566A, 566B, 566C, and 566D to electrically isolate the segments from one another. Each of segments 566A, 566B, 566C, and 566D is connected to a corresponding transimpedance amplifier 573A, 573B, 573C, and 573D, as described below, which outputs a voltage based on or proportional to the induced current in each of segments 566A, 566B, 566C, and 566D. In some examples, a single transimpedance amplifier or multiple transimpedance amplifiers may be used to determine the total charge on a droplet passing through aperture 564.

[0089] FIG. 6 illustrates a cross-sectional view of a charged droplet detector 510 showing the electrical connections of the sensor layers, according to at least some examples. The charged droplet detector 510 is shown with the same layers described with respect to FIG. 4, including three conductive layers 560, 561, and 562 separated by two insulating layers 567 and 568. In some embodiments, the total thickness of the charged droplet detector 510 is about 1 mm, but it can be more or less than 1 mm. The layers can all have a thickness of 200 micrometers (0.008 inches) in some embodiments. In some embodiments, the total thickness can be about 2 mm. The charged droplet detector 510 can be mounted between a charged droplet source and a target such that droplets travel upward through an aperture 509. Mounts for XYZ positioning of the detector above the charged droplet source and alignment of the aperture 509 with respect to the transducer axis are not shown.

[0090] For droplet sensing, the two conductive layers 560 and 562, as well as any other layers, such as the sensor layer 561, can be electrically coupled to or biased against a reference voltage, such as a high voltage supply, and each of the sections 566A, 566B, 566C, and 566D of the sensor layer 561 can be electrically coupled to a circuit element, such as a transimpedance amplifier, to generate a signal, such as an induced current or voltage. Each of the conductive layers 560 and 562 and the sensor layer 561 can optionally be biased to a high voltage to generate a charge on the droplet as it passes through the aperture 564, such as in the case of a droplet generator that does not generate charged droplets. In some examples, the high voltage can also be applied to a target using a wire mesh grid or directly to an open-port probe. As the droplet passes through the aperture 564, the electric field resulting from the voltage bias can exert a force on the charged droplet, which can accelerate, decelerate, or deflect the droplet's trajectory in an undesirable manner. Therefore, a uniform electric field along the droplet trajectory, such as a uniform electric field along the axis between the droplet generator and the target, is advantageous. In some examples, one or more of conductive layers 560 and 562 or any other conductive layers may be floating and / or at a reference (e.g., ground) voltage. The examples provided and described herein may include a fluid reservoir that is biased to a high potential while charged droplet detector 510 is at a reference or ground potential. It should be understood that other implementations, such as biasing charged droplet detector 510 to a high voltage, may be used to induce charge on ejected droplets and may be suitable for use with the systems and methods described herein.

[0091] In some examples, each section 566A, 566B, 566C, and 566D may be associated with a transimpedance amplifier, which may optionally comprise one or more transimpedance amplifiers, although only one transimpedance amplifier 573 is shown in FIG. 6. For the example shown in FIG. 5, four transimpedance amplifiers 573A, 573B, 573C, and 573D are shown, each coupled to a corresponding section of the sensor layer 561. In some examples, the sensor layer 561 can consist of any number of sections, each coupled to a corresponding transimpedance amplifier or other circuit element. In some embodiments, the transimpedance unit 573 can include a Peltier-cooled input transistor with feedback components such as a Cf of 0.5 pF and an Rf of 1 gigaohm. The integrator circuit of the transimpedance unit 573 converts the current in the section of the sensor layer 561 induced by the charged droplet 549 into a voltage output.

[0092] 7 illustrates an exploded view of the layers of a charged droplet controller 710, according to at least some examples. The charged droplet controller 710 may correspond to one implementation of the charged droplet management device 110 of FIG. 1. The charged droplet controller 710 includes a first conductive layer 760, a first supporting or insulating layer 761, a second conductive layer 762, and a second supporting or insulating layer 763. The conductive layers of the charged droplet controller, which may be separated, may be referred to herein as conductive control layers. When charged droplet 749 passes through an opening in charged droplet controller 710, such as an opening having (or including) openings 764, 765, 766, and 767, an electric field may be applied between opposing sections in conductive layer 760 or 762, for example, between sections 768A and 768B of first conductive layer 760 and between sections 768C and 768D of second conductive layer 762.

[0093] An electric field can be applied by holding each of opposing segments within the conductive layer at a different relative voltage. As shown, segments 768A and 768B of first conductive layer 760 generate an electric field along the X direction, which can induce deflection of charged droplets 749 along the X direction, while segments 768C and 768D of second conductive layer 762 generate an electric field along the Y direction, which can induce deflection of charged droplets 749 along the Y direction. Although segments 768A, 768B, 768C, and 768D are shown in FIG. 7 as being located within separate conductive layers 762, in some charged droplet controllers, all of the segments for modifying the trajectories of charged droplets can be located within the same plane or layer. Furthermore, although four segments are shown, any suitable number of segments can be used, and the voltages between the various segments can be adjusted to generate the appropriate electric fields that modify the trajectories of charged droplets as they pass through the aperture. Additionally, although two support or insulating layers 761 and 763 are depicted in Figure 7, any suitable number of support or insulating layers may be used. For example, some configurations may not use any support or insulating layers (e.g., if the conductive layer provides its own support structure). Other examples may use only one support or insulating layer (e.g., if all of the sections of the conductive layer are in the same plane or layer and are supported by a single support or insulating layer).

[0094] Optionally, additional conductive layers may be used in the charged droplet controller beyond those used to adjust the trajectory of the charged droplet as it passes through the aperture. In some examples, one or more ground or reference conductive layers, similar to conductive layers 362 and 360 shown in FIG. 3, may be positioned above and / or below the main conductive layer containing the segments and used to modify the trajectory of the charged droplet. The use of such ground or reference conductive layers may be useful to limit the extent of the electric field generated by the segmented conductive layer from extending significantly beyond the aperture. In some examples, all components of the charged droplet controller may be biased at a relative potential above or below ground and / or with respect to the potential at the droplet generator or target. The voltage applied at each of the segments may be controlled using one or more voltage controllers or voltage generators, which may be integrated as part of the charged droplet controller 710 or provided by external circuitry.

[0095] 7 as planar, while insulating layer 761 is shown with a particular thickness, any suitable thickness dimensions can be used. For example, insulating and / or conductive layers in a charged droplet controller may have thicknesses of 0.1 mm to 0.2 mm, 0.2 mm to 0.3 mm, 0.3 mm to 0.4 mm, 0.4 mm to 0.5 mm, 0.5 mm to 0.6 mm, 0.6 mm to 0.7 mm, 0.7 mm to 0.8 mm, 0.8 mm to 0.9 mm, 0.9 mm to 1 mm, 1 mm to 1.1 mm, 1.1 mm to 1.2 mm, 1.0 mm to 1.3 mm, 1.4 mm to 1.5 mm, 1.6 mm to 1.7 mm, 1.8 mm to 1.9 mm, 1.9 mm to 2.0 mm, 1.1 mm to 2.2 mm, 1.2 mm to 2.3 mm, 1.4 mm to 2.5 mm, 1.6 mm to 2.7 mm, 1.8 mm to 2.9 mm, 1.9 mm to 2.4 mm, 1.9 mm to 2.5 mm, 1.9 mm to 2.6 mm, 1.9 mm to 2.8 mm, 1.9 mm to 2.9 ... .2mm~1.3mm, 1.3mm~1.4mm, 1.4mm~1.5mm, 1.5mm~1.6mm, 1.6mm~1.7mm, 1.7mm~1.8mm, 1.8mm~1.9 mm, 1.9mm~2mm, 2mm~2.1mm, 2.1mm~2.2mm, 2.2mm~2.3mm, 2.3mm~2.4mm, 2.4mm~2.5mm, 2.5mm~2.6m m, 2.6mm~2.7mm, 2.7mm~2.8mm, 2.8mm~2.9mm, 2.9mm~3mm, 3mm~3.1mm, 3.1mm~3.2mm, 3.2mm~3.3m m, 3.3mm~3.4mm, 3.4mm~3.5mm, 3.5mm~3.6mm, 3.6mm~3.7mm, 3.7mm~3.8mm, 3.8mm~3.9mm, 3.9mm~4 The thickness may be 0.1 mm to 5 mm, such as 0.1 mm to 1.0 mm or greater, including 0.1 mm to 5 mm, 4 mm to 4.1 mm, 4.1 mm to 4.2 mm, 4.2 mm to 4.3 mm, 4.3 mm to 4.4 mm, 4.4 mm to 4.5 mm, 4.5 mm to 4.6 mm, 4.6 mm to 4.7 mm, 4.7 mm to 4.8 mm, 4.8 mm to 4.9 mm, 4.9 mm to 5 mm, etc. Thicknesses for the conductive and insulating layers may extend outside these ranges in some cases, and in particular, conductive layers may have thicknesses less than 0.2 mm or less than 0.1 mm. In some cases, the ratio of the diameter of the opening to the thickness of one or more of the insulating layers may be 0.25 to 4. In some cases, the ratio of the diameter of the opening to the thickness of one or more of the conductive layers may be 0.25 to 4. Optionally, the thickness for the conductive layer may be dictated by manufacturing, such as in the case of a charged droplet management device comprising a printed circuit board, where the copper foil or copper plating thickness may be standardized (e.g., a copper layer thickness of about 35 μm, about 70 μm, about 105 μm, or about 140 μm).In some examples, the thickness of each insulating layer is the same, but they can optionally be different. In some examples, the thickness of each conductive layer (if multiple conductive layers are present) is the same, but they can optionally be different. In some examples, the thicknesses of the conductive and insulating layers are different from each other, but they can optionally be the same. In some examples, the use of a conductive layer with a thickness greater than 0.1 mm or 0.2 mm can be useful for providing a stronger trajectory change to the charged droplets, as a thicker conductive layer can allow the charged droplets more time to interact with the electric field. Such a case, although separated in some examples, can be considered a conductive layer with a cylindrical opening.

[0096] The strength of the electric field generated between segments 768A and 768B of first conductive layer 760 and segments 768C and 768D of second conductive layer 762 can be determined, for example, by the relative voltage of each segment or the voltage difference between opposing segments. In some examples, any suitable voltage difference can be applied between opposing segments, but very high voltages can generate electric fields high enough to break down the air and induce electrostatic discharge, a condition that is desirably avoided. In some examples, the relative voltage between different segments can be between 0 V and 500 V or more, depending on the geometry of the segments. Exemplary relative voltages between different segments can be 0V to 25V, 0V to 50V, 0V to 75V, 0V to 100V, 0V to 125V, 0V to 150V, 0V to 175V, 0V to 200V, 0V to 225V, 0V to 250V, 0V to 275V, 0V to 300V, 0V to 325V, 0V to 350V, 0V to 375V, 0V to 400V, 0V to 425V, 0V to 450V, 0V to 475V, or 0V to 500V. It should be understood that the higher the voltage difference between the segments, the stronger the electric field and the greater the orbital adjustment.

[0097] A feedback mechanism may be implemented in the systems, techniques, devices, and methods described herein, such as to enable the voltages applied to different sections of the charged droplet controller to be determined and selected based on the required trajectory adjustment. For example, by measuring the charged droplet position, such as using a charged droplet detector as described herein and using fixed or known geometric parameters for the system and target, the voltages required for application to different sections within the charged droplet controller can be determined. For example, assuming the charged droplet detector and charged droplet controller have their apertures aligned with the ejection axis of the charged droplet generator and further aligned with the target, droplets passing through the exact center of the aperture of the charged droplet detector and charged droplet controller will not require any trajectory adjustment, and thereby the voltages applied to the sections of the charged droplet controller can be selected to generate very small or zero electric fields so that no deflection to the trajectory will be applied. In another example, a droplet that is misdirected from the aperture center and passes closer to one segment than another segment will have its position identified by the charged droplet detector, allowing for the determination and selection of appropriate voltages to apply to the segments of the charged droplet controller to correct the trajectory of the charged droplet so that it arrives on-axis at the target. In some examples, a lookup table or adaptive analytical solution may be used to generate voltages to be applied to different segments of the charged droplet controller based on the determined position of the charged droplet in the charged droplet detector.

[0098] FIG. 8 illustrates a side view of a charged droplet controller 810, which may be different from or the same as components of charged droplet management device 110 of FIG. 1 , charged droplet controller 210B of FIG. 2 , or charged droplet controller 710 of FIG. 7 , according to at least some examples. While layers of charged droplet controller 810 are shown, additional layers may be implemented in some examples. In some examples, charged droplet controller 810 may be (or may comprise) a printed circuit board including a printed and / or silkscreened top layer 870 and solder mask layers 869 and 871. Within the printed circuit of charged droplet controller 810 are conductive layers 860 and 862, as described above with reference to the components of charged droplet controller 710 of FIG. 7 . Insulating layers 861 and 863 are positioned between conductive layers 860 and 862, such as to support and / or electrically insulate conductive layers 860 and 862 from each other. All layers define an opening 809 through which the charged droplet detector 810 passes. Insulating layers 861 and 863 may have a thickness of 0.1 millimeter to 1.0 millimeter in some examples. While the charged droplet controller 810 in FIG. 8 shows two total conductive layers and two total insulating layers, more or fewer conductive and / or insulating layers may be included in other examples. In some examples, the layers including conductive layers 860 and 862 and insulating layers 861 and 863, as well as any other layers, may be arranged in a non-parallel manner such that the layers are not along parallel planes. In some embodiments, conductive layers 860 and 862 may be (or consist of), for example, copper or gold. Conductive layers 860 and 862 may have any suitable lateral dimensions, such as between 0.5 cm and 5 cm (e.g., 0.5 cm, 0.6 cm, 0.7 cm, 0.8 cm, 0.9 cm, 1.0 cm, 1.1 cm, 1.2 cm, 1.3 cm, 1.4 cm, 1.5 cm, 2 cm, 2.5 cm, 3 cm, 3.5 cm, 4 cm, 4.5 cm, or 5 cm), although larger or smaller dimensions may be implemented.In some examples, conductive layers 860 and 862, or components thereof, such as segments of conductive layers 860 and 862, may have larger lateral dimensions than insulating layers 861 and 863 to provide electrical connections to one or more voltage controllers. Insulating layers 861 and 863 may be formed from suitable dielectric and / or insulating materials, such as laminates (e.g., as used in some printed circuit boards).

[0099] 9 illustrates a top plan view of a conductive layer 960 of a charged droplet controller 910, which may be the same as or different from the charged droplet controller of the charged droplet management device 110 of FIG. 1 , the charged droplet controller 210B of FIG. 2 , the charged droplet controller 710 of FIG. 7 , or the charged droplet controller 810 of FIG. 8 , according to at least some examples. The conductive layer 960 defines an opening 965, which in some embodiments may be at least a portion of the opening 909 of the charged droplet controller 910 and may have a diameter of 2 mm. In some examples, the diameter may be greater than or less than 2 mm. Sections 968A, 968B, 968C, and 968D of the conductive layer 960 divide the layer into equally sized sections that surround the opening 965, with each section optionally providing an equal portion of the perimeter of the opening 965. Spaces or insulating regions 907 are positioned between segments 968A, 968B, 968C, and 968D to electrically isolate the segments from one another. Each of segments 968A, 968B, 968C, and 968D is connected to a corresponding voltage controller 974A, 974B, 974C, and 974D, as described below, to generate an electric field at aperture 965 of a desired or predetermined magnitude and orientation to modify the trajectory of charged droplets 949 as they pass through aperture 965. In some examples, a single voltage controller or multiple voltage controllers may be used to apply voltages between different segments of conductive layer 960. Optionally, a single voltage controller may be connected between opposing segments to set a voltage difference between the opposing segments. For example, voltage controllers 974A and 974C can be the same voltage controller for setting the voltage difference between segments 968A and 968C, or voltage controllers 974B and 974D can be the same voltage controller for setting the voltage difference between segments 968B and 968D. In some examples, each segment 968A, 968B, 968C, and 968D can be associated with a voltage controller, which may optionally comprise one or more voltage controllers, although only one voltage controller 974 is shown in FIG.For the example shown in FIG. 9, four transimpedance amplifiers 974A, 974B, 974C, and 974D are shown, each coupled to a corresponding section of conductive layer 960.

[0100] FIG. 10 illustrates a cross-sectional view of a charged droplet controller 910 showing the electrical connections of the conductive layers, according to at least some examples. The charged droplet controller 910 is shown with different numbers and configurations of layers as described with respect to FIG. 8, including one conductive layer 960 and one insulating layer 961. In some embodiments, the total thickness of the charged droplet controller 910 is about 0.4 mm, but it can be more or less than 0.4 mm. All of the layers can have a thickness of 200 micrometers (0.008 inches) in some embodiments. In some embodiments, the total thickness can be about 0.8 mm. The charged droplet controller 910 can be mounted between the charged droplet source and the target so that the droplets travel upward through the aperture 909. Mounts for XYZ positioning of the controller above the charged droplet source and alignment of the aperture 909 to the transducer axis are not shown.

[0101] With respect to droplet control, a voltage difference applied between opposing segments 968A and 968C can be used to adjust the deflection of charged droplets along the Y direction, and a voltage difference applied between opposing segments 968B and 968D can be used to adjust the deflection of charged droplets along the X direction. The voltages applied to the segments of conductive layer 960 can be biased above or below ground potential to establish an overall floating potential to charged droplet controller 910, which can be used to accelerate, decelerate, or maintain the relative velocity of charged droplets approaching or departing from charged droplet controller 910. As the droplets pass through aperture 965, the electric fields generated by the voltages applied to the different segments can exert forces on the charged droplets that can accelerate, decelerate, and deflect the trajectory of charged droplets 949 in a controlled manner.

[0102] Figures 11, 12, and 13 illustrate charts showing values ​​corresponding to induced currents in different sections as charged droplets pass through an aperture of a charged droplet detector. Figure 11 illustrates differential currents flowing through opposing sections and will be discussed in more detail below. Figure 12 illustrates chart 1279 showing currents from sections of a sensor layer of a charged droplet detector resulting from a charged droplet traveling through an aperture in the charged droplet detector over time, according to at least some examples. Each of the illustrated data sets 1282, 1281, and 1280 represents currents measured in a section as a charged droplet is ejected from a fluid reservoir, through an aperture, and toward a target location. As shown, data sets 1282, 1281, and 1280 represent currents in sections at different lateral offsets of the charged droplet from the section of the sensor layer. For example, data set 1280 may represent a droplet passing through the center of the aperture, while data set 1282 is offset laterally closer to the section of the sensor layer, and data set 1281 is offset laterally away from the section on the opposite side of the aperture from the location associated with data set 1282. As shown, a larger current, such as that illustrated by data set 1282, represents a charged droplet positioned closer to the section than a smaller current, such as that illustrated by data set 1281. On the left side of FIG. 12 , data sets 1280, 1281, and 1282 each represent an initial induced current at t0, indicating that no charged droplet is within the aperture. When a droplet passes through the sensor layer of the charged droplet detector at t1, the current, as represented by data sets 1280, 1281, and 1282, reverses as the initial reference is passed and the direction of the induced current is reversed until t2, when the droplet exits the aperture. Similarly, in FIG. 13, the output voltages from the four transimpedance amplifiers are shown, with different amplitudes based on the different current values ​​of the segments over time as the droplet passes through the aperture of the charged droplet detector.For example, the measured voltage depicted in chart 1383 of FIG. 13 indicates that the corresponding droplets passed through the charged droplet detector closer to the sections associated with data sets 1385 and 1386 than to the sections associated with data sets 1384 and 1387 (as evidenced by the greater increase and decrease in voltage).

[0103] 11 illustrates a chart 1174 showing differential currents from opposing sections of a sensor layer of a charged droplet detector for different charged droplet displacement locations along an axis between a droplet source and a droplet's target destination, according to at least some examples. In chart 1174, the horizontal axis is the time when the signal is measured, which can be correlated to the vertical position (Z position) of the charged droplet, while the differential current is shown on the vertical axis. Different data sets representing different signals are shown on chart 1174, which correspond to the difference in measured current between opposing sections positioned on opposite sides of the aperture as the charged droplet passes through the aperture.

[0104] The first data set 1175 of the chart illustrates the difference in output voltage between opposing segments, such as segments 366B and 366D in FIG. 3 or segments 566B and 566D in FIG. 5, where the droplet trajectory is vertical but offset laterally from the center of the aperture toward one of the segments. A corresponding set of curves from the difference in measured current between segments 366A and 366C in FIG. 3 or segments 566A and 566C in FIG. 5 would additionally provide information about the position of the droplet along a second direction (e.g., along the Y-axis as illustrated in FIG. 5) and relative to the aperture center as the droplet passes through the aperture. If the droplet passes the center of the aperture in both directions (e.g., the X and Y directions as illustrated in FIG. 5), all of the difference curves would be substantially flat and show a 0 V output. The output from each segment may be weighted or normalized relative to the sum of the currents through all segments (essentially normalizing the droplet charge from the differential measurement), or may be weighted or normalized using a weighting factor representing the area of ​​the segment or the percentage of the aperture circumference occupied by the segment. In some examples, the output may be normalized by dividing each output by the sum of all outputs from each sensor. In some examples, the summed signal from all segments has a bipolar pulse shape due to the droplet passing through the device. The magnitude of this summed signal can serve as an appropriate normalization factor for the differential current. The polarity of the droplet charge may be extracted by noting the phase of the bipolar pulse obtained from summing the sensor signals. The second data set 1176 illustrates the difference in measured current between segments with a droplet trajectory offset from the central axis of the aperture by a first amount toward the second segment in the opposite direction to the first data set 1175. The third data set 1177 involves droplets offset toward the first of the segments along the first direction (e.g., along the X-axis illustrated in FIG. 5) by a second amount less than the first amount, thereby illustrating the difference in measured current between the segments resulting in less difference in measured current between opposing segments.A fourth data set 1178 of chart 1174 illustrates the difference in measured current between segments with droplets offset from the central axis of the aperture by a second amount toward the second segment in the opposite direction to the third data set 1177. The differential currents from the segments, once normalized by the summed sensor signal as described above, can be used to determine the lateral offset of the droplet trajectory along the first direction (e.g., along the X-axis illustrated in FIGS. 3 and 5 ), along with knowledge of the droplet charge polarity, similarly obtained from the summed sensor signal. A similar analysis of the differential currents from additional segments (e.g., orthogonal segments) can enable the determination of the lateral offset of the droplet trajectory along the Y-axis in FIGS. 3 and 5 . The lateral offsets along the X and Y axes are used to generate weights that identify droplet locations, such as a droplet location weight map, where the relative locations of the droplets may correspond to the weights of the currents from opposing segments.

[0105] The output voltage and / or differential current can be useful for identifying not only the location of a charged droplet but also its velocity. In some examples, the sum of all output voltages or currents can be used to determine droplet charge and droplet velocity (e.g., using sum 1494 in FIG. 14). In chart 1174, the horizontal axis is the time when the signal is measured, which can be correlated to the vertical position (Z position) of the charged droplet, while the differential current is shown on the vertical axis. Velocity can be determined, for example, based on the time it takes to cross the charged droplet detector. Because droplets travel through the device at an essentially constant velocity, position as shown in charts 1174 and 1279 relates to time times droplet velocity. In charts 1174 and 1279, there are three distinct features for each of the curves: a peak, a minimum, and a zero crossing that occurs approximately halfway between the peak and minimum. The respective times associated with each of these features are T peak , T min , and T zerocrossing The time at which acoustic energy is transmitted to the fluid surface to generate droplets can be set as T0. The droplets are generated at time T zerocrossing(This is when the current is zero as the droplet reaches the minimum distance to each section.) Given the height of the sensor layer above the well fluid (which will generally be the case), let this height be H sensor Then, one magnitude of the droplet velocity is expressed by the formula: H sensor / (T zerocrossing -T0), which yields a velocity based on the time it takes a droplet to reach the sensor layer from the fluid surface, given the height of the sensor layer above the fluid surface.

[0106] In some instances, the droplet velocity is T peak and T min This difference may be related to the droplet velocity and the distance between the conductive layers (e.g., conductive layers 362 and 360 in FIG. 3), referred to herein as distance d. For an exemplary geometry of the conductive layers, the time T peak -T min =0.71×d / v droplet where v droplet is the "instantaneous" velocity of the droplet as it passes through the sensor layer. Therefore, the instantaneous velocity is v droplet = 0.71 × d / |T peak -T min The coefficient of 0.71 comes from modeling of the device, but is strictly due to its geometry and is independent of droplet charge, volume, and other factors; therefore, other coefficients may be used for other geometries.

[0107] FIG. 14 illustrates a chart 1488 showing output voltage signals 1489, 1490, 1491, and 1492 received from transimpedance amplifiers associated with four sections of the sensor layer, such as those shown and described with respect to FIG. 5 above, and a sum 1494 of all output voltage signals. The output voltage signals can be used to determine a location 1496 of a droplet traveling through an aperture in a sensor device, according to at least some examples. Using the output signals of chart 1488 and performing the calculations described herein, an inferred XY location 1496 of the droplet is determined and is shown in FIG. 15. The inferred XY location 1496 of the droplet corresponds to the predicted location (predicted using the output signals as described herein) where the droplet will pass through the aperture, while the stage position XY location 1495 indicates a transducer axis defined by the position of the stage on which the transducer is located, such as transducer axis 118 of FIG. 1. That is, stage position XY location 1495 is where the droplet is expected to pass through the aperture, assuming the droplet trajectory is aligned along the axis of the acoustic transducer. As shown in Figure 15, inferred XY location 1496 and stage position XY location 1495 coincide, thus confirming the use of induced currents to predict droplet location as described herein. As described above, induced currents in sections of the sensor layer can be used to determine position based on the relative sizes of the peaks in output voltage signals 1489, 1490, 1491, and 1492.

[0108] 16 illustrates a chart 1600 providing output voltage signals 1601, 1602, 1603, and 1604 corresponding to a main droplet 1608 and satellite droplets 1606 traveling through an aperture, as well as a sum 1609 of all output voltage signals, according to at least some examples. Satellite droplets 1606 may be ejected from the fluid during a given ejection and may be unwanted secondary droplets; satellite droplets 1606 may be generated if the device is not properly adjusted or is overpowered when main droplet 1608 is generated. The resulting signals from the four sections of the sensor layer as output from the transimpedance amplifier are shown in FIG. 16, and the inferred XY locations of main droplet 1608 and satellite droplets 1606, along with stage position 1607, are shown in FIG. 17. The locations of the main droplet 1608 and the satellite droplets 1606 are determined from the induced current of the illustrated sensor layer section, which identifies peaks indicative of the locations of the main droplet 1608 and the satellite droplets 1606. The location of the satellite droplet 1606 can be determined based on relative amplitudes, for example, to distinguish between the main droplet 1608 and the satellite droplet 1606. For example, in FIG. 16 , the satellite droplet 1606 is identifiable at T2, while the main droplet 1608 is at T1 and is clearly identifiable based on the difference in the peak of the data set representing the sum 1609. In some embodiments, the identification of the satellite droplets can be useful in determining whether ejection parameters (e.g., transducer parameters) need to be adjusted. For example, the method can include determining that a satellite droplet was ejected in a particular ejection based on measuring values ​​corresponding to the induced current as described herein. Based on this determination, it may be determined that the transducer parameters need to be adjusted to prevent further ejection of satellite droplets. The transducer parameters may then be adjusted accordingly (e.g., by reducing the acoustic signal amplitude or frequency) for the next ejection. These may be repeated as often as necessary to provide iterative fine-tuning of the ejection and prevent, or at least reduce, the ejection of satellite droplets.

[0109] 18 illustrates a flowchart showing a process for detecting charged droplets from a droplet generator, according to at least some examples. Any suitable computing system or group of computing systems can be used to implement aspects of the methods described herein. For example, FIG. 26 depicts an example computing device 2600 that may be at least part of a computing system for implementing operations or methods described herein.

[0110] At block 1802, method 1800 includes positioning a charged droplet detector between a droplet generator and a target, such as shown in Figures 1 and 2. The detector may be a component of charged droplet management device 110 of Figure 1, charged droplet detector 210A of Figure 2, charged droplet detector 310 of Figure 3, charged droplet detector 410 of Figure 4, or charged droplet detector 510 of Figure 6, according to at least some examples. The charged droplet detector may be positioned with an aperture positioned in alignment with the ejection axis of the droplet generator (e.g., aligned with the transducer axis of an acoustic droplet ejection system).

[0111] At block 1804, the method 1800 includes directing charged droplets from a droplet generator toward a target through an aperture of a charged droplet detector. The charged droplets may be propelled by a droplet generator, for example, as described with respect to FIG. 1.

[0112] At block 1806, method 1800 includes analyzing the voltage signals generated by the charged droplet detector to determine the position and / or velocity of the droplet. The voltage signals may be output by transimpedance amplifiers connected to respective ones of the sections of the sensor layer. The voltage signals may correspond to induced currents in each section as a result of the passage of the charged droplet through the aperture. As described herein, the location of the droplet may be determined based on a weighting of the voltage signals from the sections of the sensor layer.

[0113] Figure 19 illustrates a top plan view of a conductive layer 1960 of a charged droplet controller, which may be the same as or different from the charged droplet detector of charged droplet management device 110 of Figure 1, charged droplet controller 210B of Figure 2, charged droplet controller 710 of Figure 7, charged droplet controller 810 of Figure 8, or charged droplet controller 810 of Figure 8, according to at least some examples. In Figure 19, voltages V1, V2, V3, and V4 are shown applied to sections 1968A, 1968B, 1968C, and 1968D of conductive layer 1960, respectively.

[0114] Figures 20, 21, and 22 illustrate the relative positions of the charged droplet at a first Z position (+) and a second Z position (O), as measured by two charged droplet detectors on opposite sides of the charged droplet controller, where voltages are applied to sections 1968A, 1968B, 1968C, and 1968D of the charged droplet controller as in Figure 19. In Figures 20, 21, and 22, the first Z position 2095(+) of the charged droplet is determined to be offset along both the X and Y directions from the center 2019 of the aperture.

[0115] 20 shows a configuration in which the voltage difference applied between sections 1968A and 1968C is zero (V1-V3=0V) and the voltage difference applied between sections 1968B and 1968D is zero (V2-V4=0V), indicating that the charged droplet controller is not deflecting the charged droplet. A second Z position 2096(O) of the charged droplet is shown in FIG. 20 and is similarly off-center 2019.

[0116] Figure 21 shows a configuration in which the voltage difference applied between sections 1968A and 1968C is zero (V1-V3=0V), but the voltage difference applied between sections 1968B and 1968D is 200V (V2-V4=200V), indicating that the charged droplet controller is deflecting the charged droplet along the X direction but not along the Y direction. A second Z position 2097(O) of the charged droplet is shown in Figure 21 and continues to be offset from center 2019, but to a lesser extent in the X direction than in Figure 20, indicating that the adjustment of the charged droplet trajectory applied by the charged droplet controller provides some correction to the trajectory, but further correction can make additional improvement.

[0117] Figure 22 shows a configuration in which the voltage difference applied between sections 1968A and 1968C is 400V (V1-V3=400V) and the voltage difference applied between sections 1968B and 1968D is 400V (V2-V4=400V), and the charged droplet controller deflects the charged droplets along the X and Y directions to an extent that exceeds the X-direction deflection in Figure 21. The position 2098(O) of the charged droplet on the substrate under such voltage conditions is shown in Figure 22 and is corrected very close to the center 2019. It should be understood that the voltages applied to the various sections referenced above with respect to Figures 20, 21, and 22 are exemplary only and are not intended to be limiting. Any suitable voltage or voltage difference for adjusting the trajectory of the charged droplets can be used, and such voltage or difference can be determined by the geometry of the system, the position and / or velocity of the charged droplets, and / or the desired change in trajectory (including magnitude and direction).

[0118] 23 illustrates a flowchart showing a process for controlling charged droplets ejected from a droplet generator, according to at least some examples. Any suitable computing system or group of computing systems can be used to implement aspects of the methods described herein. For example, FIG. 26 depicts an example computing device 2600 that can be at least part of a computing system for implementing operations or methods described herein.

[0119] At block 2302, method 2300 includes positioning a charged droplet detector and a charged droplet controller between a droplet generator and a target, such as shown in Figures 1 and 2. The charged droplet detector may be a component of charged droplet management device 110 of Figure 1 or charged droplet detector 210A of Figure 2, according to at least some examples. The charged droplet controller may be a component of charged droplet management device 110 of Figure 1, charged droplet controller 210B of Figure 2, charged droplet controller 710 of Figure 7, charged droplet controller 810 of Figure 8, or charged droplet controller 910 of Figure 10, according to at least some examples. The charged droplet controller may be positioned with an aperture positioned in alignment with the ejection axis of the droplet generator (e.g., aligned with the transducer axis of an acoustic droplet ejection system).

[0120] At block 2304, the method 2300 includes directing charged droplets from a droplet generator toward a target through an aperture of a charged droplet detector. The charged droplets may be propelled by a droplet generator such as described with respect to FIG. 1.

[0121] At block 2306, method 2300 includes determining a plurality of values ​​based on or proportional to an induced current in the charged droplet detector. The induced current may be generated when the charged droplet passes through a first aperture of the charged droplet detector. The induced current may be based on or proportional to the position of the charged droplet as it passes through the aperture and may indicate the position of the charged droplet relative to a central axis passing through the aperture. By determining a plurality of values ​​based on or proportional to the induced current, the position of the charged droplet may be determined, and corrective action may be taken to correct and / or alter the trajectory of the charged droplet as it passes through the aperture of the charged droplet controller, as described below.

[0122] At block 2308, method 2300 includes directing the charged droplets through a second opening of the charged droplet controller. The second opening or opening of the charged droplet controller may be aligned with the opening of the charged droplet detector. Thus, the charged droplets may be propelled by a droplet generator such as described with reference to FIG. 1, pass through the opening of the charged droplet detector, and naturally be directed toward and continue through the opening of the charged droplet controller.

[0123] At block 2310, method 2300 includes applying a voltage to one or more conductive layer sections of the charged droplet controller to modify the droplet trajectory. The voltage may be generated automatically or using feedback of the velocity or position of the charged droplets, for example, as determined by the charged droplet detector. In other examples, the voltage may be empirically determined and applied, such as to control the trajectory of additional droplets via user input, to adjust or optimize the droplet trajectory to reach or improve arrival at the target. In other examples, the voltage may be based on or proportional to the corresponding induced current in the charged droplet detector, such as when the induced current is provided to a circuit or component that generates a voltage directly from the induced current, optionally with application of a filter, polarity reversal, magnitude adjustment, or time shift or delay. In some examples, the magnitude of the voltage may be adjusted according to the total charge for the charged droplets or the charge-to-volume ratio for the charged droplets. In some examples, a time shift or delay may be applied to the voltage according to the distance between the charged droplet controller and the charged droplet detector and the velocity of the charged droplets.

[0124] As discussed above, charged droplets may travel at high speed from the charged droplet generator through the aperture of the charged droplet detector and charged droplet controller. Therefore, there may not be enough time for calculation of the induced current measured in the charged droplet detector. Therefore, the voltage applied by the charged droplet controller may be applied without calculation. Instead, the voltage applied by the charged droplet controller may simply be based on or proportional to the induced current measured in the charged droplet detector; and / or may be its reciprocal. The voltage applied by the charged droplet controller may be based on the principle of stochastic cooling. In some embodiments, feedback about the position of the charged droplet after passing through the charged droplet controller may be collected, and method 2300 may include determining or adjusting the magnitude of the voltage in the set of voltages, such as for subsequent charged droplets.

[0125] In embodiments, an adequate distance may exist between the charged drop detector and the charged drop controller, so that a voltage need not be applied immediately. However, the distance may still not be sufficient for extended calculations. In such embodiments, a delay time may be determined, and the application of a voltage to the charged drop controller may be adjusted to account for when the charged drop will pass through the aperture of the charged drop controller. The delay time may be determined by the magnitude of the velocity of the charged drop, which may be similar to the velocity of the previous drop, and the size of the distance between the charged drop detector and the charged drop controller. However, even when the delay time is not sufficient for the calculation of a value ultimately derived from the charged drop detector, a signal corresponding to the value determined in the charged drop detector may be fed directly to the charged drop controller to apply a voltage without intermediate calculations, which may reduce system complexity and result in sufficient and / or optimal correction of the charged drop trajectory and / or position.

[0126] 24 illustrates a flowchart showing a process for detecting and controlling charged droplets ejected from a droplet generator using a feedback scheme, according to at least some examples. Any suitable computing system or group of computing systems can be used to implement aspects of the methods described herein. For example, FIG. 26 depicts an example computing device 2600 that can be at least part of a computing system for implementing operations or methods described herein.

[0127] At block 2402, method 2400 includes positioning a charged droplet detector between a droplet generator and a charged droplet controller, such as shown in Figure 2. The charged droplet detector may be a component of charged droplet management device 110 of Figure 1, charged droplet detector 210A of Figure 2, charged droplet detector 310 of Figure 3, charged droplet detector 410 of Figure 4, or charged droplet detector 510 of Figure 6, according to at least some examples. The charged droplet controller may be a component of charged droplet management device 110 of Figure 1, charged droplet controller 210B of Figure 2, charged droplet controller 710 of Figure 7, charged droplet controller 810 of Figure 8, or charged droplet controller 910 of Figure 10, according to at least some examples. The charged drop detector and charged drop controller may be positioned with their apertures aligned with each other and / or with the ejection axis of the drop generator (eg, aligned with the transducer axis of an acoustic drop ejection system).

[0128] At block 2404, the method 2400 includes directing the charged droplets from the droplet generator toward and through an opening in a charged droplet detector and charged droplet controller. The charged droplets may be propelled by a droplet generator such as described with respect to FIG.

[0129] At block 2406, method 2400 includes analyzing a voltage signal generated by the charged droplet detector to determine the position and / or velocity of the droplet. The voltage signal may be output by a transimpedance amplifier connected to each one of the sections of the sensor layer of the charged droplet detector. The voltage signal may correspond to an induced current in each section as a result of the passage of the charged droplet through the aperture. As described herein, the location of the droplet may be determined based on a weighting of the voltage signals from the sections of the sensor layer. In some examples, the voltage waveform from the transimpedance amplifier may be analyzed by a signal processing component to extract the position and / or velocity of the charged droplet in the charged droplet detector.

[0130] At block 2410, method 2400 includes modifying the droplet trajectory by determining and applying a voltage to one or more conductive layer segments of the charged droplet controller. The voltage may be determined using the velocity or position of the charged droplet from the signal processing component, and may be determined using a lookup table or analytical function, such as where one or more coordinates (e.g., X and Y) of the charged droplet are taken as input and a voltage for application to a segment (or a voltage difference for application to opposite segments) is determined as an output for application to the conductive layer segment.

[0131] FIG. 25A illustrates signals for the four sections of the sensor layer of a charged droplet detector corresponding to signals based on or proportional to the induced currents in each sensor layer as 10 charged droplets pass through the aperture of the charged droplet detector during a period of approximately 40 milliseconds. The signals shown in FIG. 25A represent signals after application of a smoothing filter to the raw signals. The signals of FIG. 25A can be used directly to generate signals to be applied to the four corresponding sections of the conductive layer of a charged droplet controller by reversing polarity, adjusting amplitude, applying a time delay, etc. FIG. 25B illustrates the resulting voltage signals for the four sections of the conductive layer of a charged droplet controller, which can be determined without time-consuming calculations and quickly applied to the charged droplet controller to adjust the trajectory and / or position of each charged droplet to a sufficient or optimal trajectory and / or position, etc., as each charged droplet passes through the aperture of the charged droplet controller.

[0132] 26 illustrates a block diagram of an example computing device 2600. Computing device 2600 may be any of the computers described herein, including computing devices that perform method 1800, receive signals from one or more transimpedance amplifiers, and perform, for example, method 2300, method 2400, other methods described herein, or various aspects or portions of such methods. Computing device 2600 may be or include, for example, an integrated computer, a laptop computer, a desktop computer, a tablet, a server, or other electronic device.

[0133] Computing device 2600 may include a processor 2640 that interacts with other hardware via a bus 2605. Memory 2610, which may include any suitable tangible (and non-transitory) computer-readable medium such as RAM, ROM, EEPROM, etc., may embody program components (e.g., program code 2615) that configure the operation of computing device 2600. Memory 2610 may store program code 2615, program data 2617, or both. In some examples, computing device 2600 may include input / output ("I / O") interface components 2625 (e.g., for interacting with a display 2645, keyboard, mouse, etc.) and additional storage 2630.

[0134] Computing device 2600 executes program code 2615 that configures processor 2640 to perform one or more of the operations described herein. Examples of program code 2615 include, in various examples, logic related to the flowcharts described with respect to Figures 18, 23, and 24 above. Program code 2615 may reside in memory 2610 or any suitable computer-readable medium and may be executed by processor 2640 or any other suitable processor.

[0135] Computing device 2600 may generate or receive program data 2617 by executing program code 2615. For example, sensor data, trip counters, authenticated messages, trip flags, and all of the other data described herein are examples of program data 2617 that may be used by computing device 2600 during execution of program code 2615.

[0136] The computing device 2600 may include a network component 2620. The network component 2620 may represent one or more of any components that facilitate a network connection. In some examples, the network component 2620 may facilitate a wireless connection and may include a radio interface such as IEEE 802.11, BLUETOOTH, or a radio interface for accessing a cellular telephone network (e.g., a transceiver / antenna for accessing a CDMA, GSM, UMTS, or other mobile communications network). In other examples, the network component 2620 may be wired and may include an interface such as Ethernet, USB, or IEEE 1394.

[0137] 26 depicts a computing device 2600 with a processor 2640, a system can include any number of computing devices and any number of processors. For example, multiple computing devices or multiple processors can be distributed over a wired or wireless network (e.g., a wide area network, a local area network, or the Internet). Multiple computing devices or multiple processors can perform any of the disclosed functions individually or in cooperation with each other.

[0138] Aspects of the present invention can be further understood with reference to the following non-limiting examples. (Example 1: Charged Droplet Ejection, Detection, and Control System)

[0139] Figure 27 provides an overview of an exemplary charged droplet emission, detection, and control system 2700 according to some examples. System 2700 may include components described elsewhere in this disclosure, including one or more droplet generators, such as droplet generator 101 described with reference to Figures 1 and 2, one or more charged droplet management devices, such as charged droplet management device 110 of Figure 1, one or more charged droplet detectors, such as charged droplet detector 210A of Figure 2, charged droplet detector 310 of Figure 3, charged droplet detector 410 of Figure 4, or charged droplet detector 510 of Figure 6, one or more charged droplet controllers, such as charged droplet controller 210B of Figure 2, charged droplet controller 710 of Figure 7, charged droplet controller 810 of Figure 8, or charged droplet controller 910 of Figure 10, and one or more computing devices, such as computing device 2600.

[0140] 27 includes a charged droplet control and detection system 2705. The charged droplet control and detection system 2705 may include physical hardware including, for example, a droplet generator and a charged droplet management device. As described above with reference to FIG. 1, the droplet generator of the charged droplet control and detection system may include an acoustic droplet ejection system employing toneburst excitation 2710 to drive an acoustic generator to eject droplets.

[0141] Charged droplet control and detection system 2705 may be in data communication with and / or control communication with data collection system 2715, which may comprise one or more computing devices according to embodiments described herein. As shown, a digital signal associated with tone burst excitation 2710 may be communicated to an external interrupt 2720 of data collection system 2715, which may enable data collection system 2715 to determine the time at which droplets are generated by charged droplet control and detection system 2705.

[0142] A charged droplet detector of the charged droplet control system may generate a voltage representative of the proximity of an ejected charged droplet to a section of the sensor layer, as described above, and droplet voltage detection and control device 2725 may communicate such voltage to voltage control and detection system 2730. Specifically, the voltage may be communicated to voltage amplifier circuit 2735, which then sends the amplified voltage to analog-to-digital converter 2740, which converts the voltage to a digital signal for communication to data acquisition system 2715.

[0143] In the data acquisition system 2715, a digital signal representing the voltage can be received at an analog-to-digital (ADC) interrupt 2745 or other digital input system. The ADC interrupt 2745 can extract the raw ADC data and communicate it to a timer interrupt 2750 and / or a computing system 2755. The computing system 2755 can analyze the raw ADC data and generate position data for charged droplets in the charged droplet detector. The timer interrupt 2750 can use information from the external interrupt 2720 to determine, for example, timing information for the detection of charged droplets. Such timing information and position data can be used by the computing system 2755 to determine the velocity or trajectory for the charged droplets. The raw ADC data and position data can be communicated to a local storage buffer 2760 for caching and / or storing the data locally within the data acquisition system 2715. A controller area network (CAN) bus 2765 or other input / output system may receive position data and / or raw ADC data from the local storage buffer 2760 or computing system 2755 and communicate the information to a user computing device 2770 (such as for use by an induced charge drop detection (ICDD) application 2775 running on the user computing device 2770).

[0144] For droplet trajectory control, the computing system 2755 may analyze the position data and determine an appropriate set of voltages to apply to a section of the control layer of the charged droplet controller in the charged droplet control and detection system 2705; this is optional if it is desired to determine an appropriate set of voltages to apply to a section of the control layer of the charged droplet controller. In other examples, an appropriate set of voltages to apply to a section of the control layer of the charged droplet controller may be generated directly, such as when the voltages generated by the voltage amplifier circuit 2735 are forwarded to the voltage adjustment circuit 2780 for filtering by a filtering circuit, polarity inversion by a polarity inversion circuit, time delay by a delay circuit, and / or amplitude adjustment by an amplification or attenuation circuit. The resulting voltages may be communicated to the droplet voltage detection and control device 2725 for application to the section of the control layer of the charged droplet controller to effect droplet trajectory modification.

[0145] While example subject matter of the present invention is described herein with particularity to meet statutory requirements, this description is not necessarily intended to limit the scope of the claims. The claimed subject matter may be embodied in other ways, may include different elements or things, and may be used in conjunction with other existing or future technologies. This description should not be construed as implying any particular order or arrangement between or among various things or elements, except when the order of particular things or arrangement of elements is explicitly described.

[0146] For clarity, not all of the routine features of the examples described herein are shown and described. Of course, it should be understood that in the development of any such actual implementation, numerous implementation-specific decisions will need to be made to achieve the developer's specific goals, such as compliance with application and business-related constraints, and that these specific goals will vary from implementation to implementation and from developer to developer.

[0147] While the present subject matter has been described in detail with respect to specific aspects thereof, it should be understood that those skilled in the art, upon achieving the foregoing understanding, may readily produce modifications to such aspects, variations thereon, and equivalents thereto. Numerous specific details are described herein to provide a thorough understanding of the claimed subject matter. However, those skilled in the art will understand that the claimed subject matter may be practiced without these specific details. In other instances, methods, apparatuses, or systems that would be known by those skilled in the art have not been described in detail so as not to obscure the claimed subject matter. Thus, the present disclosure is presented for purposes of example, not limitation, and does not exclude the inclusion of such modifications, variations, and / or additions to the present subject matter as would be readily apparent to those skilled in the art. It will be apparent to those skilled in the art that various modifications and variations can be made in the methods and systems of the present invention without departing from the spirit or scope of the invention. Therefore, it is intended that the present invention include modifications and variations thereto and their equivalents that are within the scope of the appended claims. It should be understood that any workable combination of the features and capabilities disclosed herein is also considered to be disclosed.

Claims

1. A device for detecting and controlling charged droplets from a charged droplet generator, wherein the device is A sensor element (561) having a first opening (564) through which a charged droplet (749) passes, wherein the sensor element comprises a plurality of electrically independent divided sections (566A, 566B, 566C, 566D), the plurality of divided sections arranged around the outer circumference of the first opening, and A circuit element (573) electrically coupled to each of the divided sections, wherein each of the plurality of divided sections is positioned to provide an induced current in the circuit element when the charged droplet passes through the first opening, and the circuit element is configured to generate a signal proportional to the induced current. A control element (710) having conductive control layers (760, 762) adjacent to one or more insulating layers (761, 763), wherein the conductive control layer and one or more insulating layers define a second opening of the control element, the charged droplet passes through the first opening of the sensor element and then through the second opening of the control element, the conductive control layer is a second segmented conductive layer having a second plurality of segmented divisions electrically independent of each other, the second plurality of segmented divisions arranged around the outer circumference of the second opening, and A voltage controller (974) electrically coupled to each of the second of the multiple divided sections and Equipped with, Each of the second plurality of divided sections is positioned to generate an electric field for controlling the trajectory of the charged droplet as it passes through the second opening, and the voltage controller is configured to apply a voltage to each of the second plurality of divided sections to generate the electric field, the voltage applied to the second plurality of divided sections is based on the corresponding induced current in the circuit element, the device.

2. The device according to claim 1, wherein the voltage applied to the second plurality of divided sections is proportional to the corresponding induced current in the circuit element, and preferably the voltage applied to the second plurality of divided sections includes a DC offset from a value proportional to the corresponding induced current in the circuit element (573).

3. The device according to claim 1, wherein the sensor element is positioned between the charged droplet generator and a target destination for the charged droplet generator.

4. Processor and A non-transient computer-readable storage medium communicating data with the aforementioned processor and Furthermore, The non-transient computer-readable storage medium stores processor-executable instructions, and when these instructions are executed by the processor, Receiving the signal from the aforementioned circuit element, Controlling the voltage controller to apply sets of voltages to the second plurality of divided sections. The processor is made to perform an operation that includes the following: The device according to claim 1, wherein the voltages among the set of voltages are based on the corresponding induced currents in the circuit element.

5. The aforementioned operation is, (i) Determining or adjusting the delay time for applying the set of voltages to the second plurality of divided sections in order to generate the electric field, wherein the delay time is determined using the velocity of the charged droplets. Determining or adjusting the magnitude of the set of voltages to be applied to each of the second plurality of divided sections in order to generate the electric field, wherein the magnitude is determined using the total charge for the charged droplet or the charge-to-volume ratio for the charged droplet, or Both, or (ii) The position of the charged droplet in the first opening, The arrival time of the charged droplet at the first opening, The arrival time of the charged droplet at the second opening, The velocity of the charged droplet, The total charge of the charged droplets, The charge-to-volume ratio for the charged droplet, or Presence of one or more charged satellite droplets Decide one or more of the following The device according to claim 4, further comprising:

6. A device for detecting and controlling charged droplets from a charged droplet generator, wherein the device is A sensing device having a first opening, wherein the first opening is formed in the sensing device from a first surface to a second surface, and the sensing device is The first conductive layer on the first surface, The second conductive layer on the second surface, A divided sensor layer between the first conductive layer (360) and the second conductive layer, The first and second dielectric layers are located on the opposite surface of the separated sensor layer, insulating the sensor layer separated from the first conductive layer and the second conductive layer. A sensing device comprising, wherein the divided sensor layer comprises a plurality of divisions positioned around the outer circumference of the first opening, A circuit element coupled to each of the plurality of divisions of the divided sensor layer, wherein each divided sensor layer provides an induced current to the circuit element, A control device, wherein the control device has a second opening formed in the control device, the control device comprises a divided control layer, and the divided control layer comprises a second plurality of divisions positioned around the outer periphery of the second opening, A voltage controller coupled to each of the second plurality of divisions of the divided control layer Equipped with, The voltage controller is configured to apply a voltage to each of the second plurality of divisions, the voltage being based on the corresponding induced current in the circuit element of the device.

7. Processor and A non-transient computer-readable storage medium communicating data with the aforementioned processor and Furthermore, The non-transient computer-readable storage medium stores processor-executable instructions, and when these instructions are executed by the processor, From one or more circuit elements coupled to the divided sensor layer, a plurality of measured values ​​corresponding to or based on the induced currents in the plurality of divisions when the charged droplet passes through the first opening are received. Based on the induced current in the circuit element, a set of control voltages is determined. Using the voltage controller, the set of control voltages is applied to the second plurality of divisions to change the trajectory of the charged droplets. The device according to claim 6, which causes the processor to perform an operation including the above.

8. The aforementioned operation is, (i) Determining or adjusting the delay time for applying the set of control voltages to each of the second plurality of divisions, wherein the delay time is determined using the velocity of the charged droplets, or (ii) Determining or adjusting the magnitude of the set of control voltages to be applied to each of the second plurality of divisions, wherein the magnitude is determined using the total charge for the charged droplet or the charge-to-volume ratio for the charged droplet, (iii) The position of the charged droplet in the first opening, The arrival time of the charged droplet at the first opening, The arrival time of the charged droplet at the second opening, The velocity of the charged droplet, The total charge of the charged droplets, The charge-to-volume ratio for the charged droplet, or Presence of one or more charged satellite droplets Decide one or more of the following The device according to claim 7, further comprising:

9. The device according to claim 7, wherein the set of control voltages is determined based on one or more of the position of the charged droplet, the velocity of the charged droplet, or a predetermined position of the target.

10. The device according to claim 6, wherein the partitioned control layer comprises the same number of electrically independent partitions surrounding the second opening as the number of electrically independent partitions surrounding the first opening in the partitioned sensor layer.

11. A method for sensing and controlling charged droplets from a charged droplet generator, wherein the method is: To direct the charged droplet toward the target through the first aperture of the charged droplet detector, The method involves determining a plurality of values ​​proportional to the induced current in the charged droplet detector, wherein the induced current is generated when the charged droplet passes through the first opening. The charged droplet is directed through the second opening of the charged droplet controller, When the charged droplet passes through the second opening of the charged droplet detector, a set of voltages is applied to the charged droplet controller. Includes, A method in which the voltages among the set of voltages are based on the corresponding induced current in the charged droplet detector.

12. The position of the charged droplet in the first opening, The arrival time of the charged droplet at the first opening, The arrival time of the charged droplet at the second opening, The velocity of the charged droplet, The total charge of the charged droplets, The charge-to-volume ratio for the charged droplet, or Presence of one or more charged satellite droplets The method according to claim 11, further comprising determining one or more of the following.

13. Determining or adjusting the delay time for applying the set of voltages to the charged droplet controller. Determining or adjusting the magnitude of the voltages among the aforementioned set of voltages, both The method according to claim 11, further comprising:

14. (i) The delay time is determined using the velocity of the charged droplet, or (ii) The method of claim 13, wherein the size is determined using the total charge for the charged droplet or the charge-to-volume ratio for the charged droplet.

15. The method according to claim 11, further comprising applying an acoustic signal to a fluid so that the charged droplets are ejected from the reservoir toward the first opening.

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