Fluidic device
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- 3C PROJECT TECHNOLOGIES LIMITED
- Filing Date
- 2026-01-30
- Publication Date
- 2026-08-06
Smart Images
Figure EP2026052432_06082026_PF_FP_ABST
Abstract
Description
[0001] FLUIDIC DEVICE
[0002] Field of the invention
[0003] The present invention relates to fluidic devices having a pump and a method for using fluidic devices having a pump.
[0004] Background to the invention
[0005] Fluidic devices are useful for a range of applications which involve pumping of fluids. For example, they are also known for use in medical, wet laboratory techniques and printing applications. In many applications there is a need for miniaturised fluidic devices with pumping capabilities.
[0006] It is known to provide fluidic devices having microelectromechanical system (MEMS) components in combination with control circuitry. However, it can be challenging to provide fluidic devices which have certain functionalities (e.g., sensing functionalities) whilst still being relatively straightforward to manufacture.
[0007] It is in this context that the present inventions have been devised.
[0008] Summary of the inventionIn accordance with an aspect of the present invention, there is provided a fluidic device comprising:
[0009] a substrate;
[0010] one or more piezoelectric actuators formed on the substrate, each of the piezoelectric actuators comprising a moveable piezoelectric diaphragm;
[0011] a pump comprising a first piezoelectric actuator of the one or more piezoelectric actuators;
[0012] control circuitry electrically coupled to the pump, wherein the control circuitry is configured to actuate the first piezoelectric actuator to cause movement of a fluid;
[0013] wherein the fluidic device is configured to generate a first signal indicative of a device characteristic and / or indicative of an environmental characteristic, wherein the first signal is based on the movement of at least one moveable piezoelectric diaphragm of at least one of the one or more piezoelectric actuators.
[0014] The combination of a pump, control circuitry and sensing capability facilitates the provision of a device having high system functionality. For example, it may be that the pump can be controlled based on the measurement of a device characteristic and / or an environmental characteristic using the control circuitry. Various parameters associated with the environment and device can affect the desired pump response. By providing a device with this combination of features, the pump can be controlled based on characteristics of the device and / or environment to facilitate improved performance.
[0015] It may be that the control circuitry is integrally formed within the substrate. The combination of a pump, control circuitry and sensing capability associated with the same substrate facilitates the provision of a device having high system functionality whilst also having a small form factor. Further, the use of one or more piezoelectric actuators along with integrated control circuitry facilitates relatively straightforward and cost-effective device manufacture.
[0016] The term pump will be understood to mean any use of the piezoelectric actuator to cause movement of fluid (e.g., a liquid). This includes ejection of fluid and / or reception of fluid into the fluidic device. The pumping may have a controllable rate, with determinable flow characteristics due to the use of a piezoelectric actuator to cause the fluid movement. In some embodiments, small quantities of fluid are pumped. It may be that the pump is a micropump.It may be that the fluidic device is a droplet ejector. That is, it may be that the pump is configured to eject droplets using the first piezoelectric actuator. It may be that fluidic device is for ejecting liquid. It may be that the fluidic device is a droplet ejector for ejecting liquid.
[0017] It may be that the fluidic device is configured for delivery of small volumes of fluid. For example, it may be that the fluidic device is configured for ejection of droplets having a radius of less than 50 pm. It may be that the fluidic device is configured for ejection of droplets having a radius of less than 30 pm. It may be that the fluidic device is configured for ejection of droplets having a radius of less than 20 pm. It may be that the fluidic device is configured for ejection of droplets having a radius of less than 10 pm. It may be that the fluidic device is configured for ejection of droplets having a radius of less than 3 pm.
[0018] It may be that the fluidic device is configured for ejection of droplets having a radius of greater than 1 pm. It may be that the fluidic device is configured for ejection of droplets having a radius of greater than 5 pm. It may be that the fluidic device is configured for ejection of droplets having a radius of greater than 10 pm. It may be that the fluidic device is configured for ejection of droplets having a radius of greater than 20 pm.
[0019] For example, it may be that the fluidic device is configured for ejection of droplets having a radius of greater than 1 pm and less than 30 pm. It may be that the fluidic device is configured for ejection of droplets having a radius of greater than 1 pm and less than 3 pm. It may be that the fluidic device is configured for ejection of droplets having a radius of greater than 20 pm and less than 30 pm.
[0020] It may be that the fluidic device is configured to deliver fluid for combination with another fluid (e.g., the fluid is delivered to a container for accommodating another fluid). It may be that the fluidic device is configured to deliver liquid for combination with another liquid. It may be that the fluidic device is configured to deliver liquid for combination with a gas. It may be that the fluidic device is configured for ejection of fluid into another fluid. It may be that the fluidic device is configured for ejection of droplets for combination with a gas (i.e. , to deliver droplets into an external gas).
[0021] It may be that at least one of the piezoelectric actuators (e.g., the first piezoelectric actuator) comprises a single corresponding channel therethrough for providing a fluidpath (e.g., fluid may be pumped through the channel). It may be that at least one of the piezoelectric actuators comprises multiple channels therethrough. It may be that at least one of the piezoelectric actuators comprises less than 10 channels therethrough.
[0022] Throughout the specification, where a limitation is specified in relation to “one or more” or “at least one” of a feature, where there are a plurality of the same feature, this also encompasses that limitation applying to each of, or some of, the plurality of features.
[0023] For example, it will be understood that any reference to at least one of the one or more piezoelectric actuators having a feature includes the possibility that the or each piezoelectric actuator has that feature, or some of the piezoelectric actuators have that feature - e.g., that every piezoelectric actuators has that feature unless inherently incompatible therewith.
[0024] It may be that at least one of the one or more piezoelectric actuators comprises one or more materials processable at a temperature below 450°C.
[0025] It may be that the or each moveable piezoelectric diaphragm comprises a piezoelectric body, a first electrode and a second electrode. It may be that the piezoelectric body comprises one or more piezoelectric materials processable at a temperature below 450°C. Examples of piezoelectric materials that are processable at temperatures below 450°C include aluminium nitride (AIN), zinc oxide (ZnO), and / or scandium aluminium nitride (ScAIN).
[0026] Some electronics (e.g., CMOS components) can be damaged at temperatures greater than 450°C. By using piezoelectric materials that are processable at a temperature below 450°C, MEMS and electronic components can be integrated whilst avoiding degradation of the electronics, thereby improving the operation and efficiency of the device.
[0027] The or each piezoelectric actuator is deposited on (e.g., formed on) the substrate. The piezoelectric actuator may be deposited using one or more PVD methods. Importantly, the or each piezoelectric actuator is formed on the substrate rather than being formed separately and later bonded.It may be that at least one of the piezoelectric actuators comprises a coating on at least part of the piezoelectric actuator for maintaining function of the piezoelectric actuator (e.g., for limiting the accumulation of debris). It may be that the coating comprises a hydrophobic material. It may be that the fluidic device comprises a wiper for cleaning (e.g., removing debris) the one or more piezoelectric actuators. This helps to maintain proper function of the piezoelectric actuators.
[0028] It may be that the fluidic device comprises at least one cavity formed in the substrate, wherein at least one of the one or more piezoelectric actuators defines at least part of a wall of the cavity. Typically, there will be a plurality of cavities formed in the substrate. It may be that at least one of the cavities contains a fluid. It may be that at least one cavity is in fluidic communication with at least one channel formed through the respective piezoelectric actuator (e.g., the first piezoelectric actuator).
[0029] In particular, it may be that the first piezoelectric actuator defines at least part of a wall of a first cavity. It may be that the first cavity contains a fluid. It may be that the first piezoelectric actuator comprises a channel formed therethrough. Typically, the moveable piezoelectric diaphragm of the first piezoelectric actuator is configured to deform into the first cavity to cause fluid movement via the channel.
[0030] It may be that the pump is operable to cause movement of a fluid orthogonally to the moveable piezoelectric diaphragm. It may be that the pump is operable to cause movement of a fluid orthogonally to the moveable piezoelectric diaphragm. It may be that the pump is operable to cause movement of a fluid orthogonally to the substrate. It may be that the pump is not operable to cause movement of a fluid in the plane of the substrate. It may be that the pump is operable to cause movement of a fluid through the moveable piezoelectric diaphragm. It may be that the pump is operable to cause movement of the fluid by ejecting a droplet of the fluid. The fluidic device may be a droplet ejector which ejects droplets through the moveable piezoelectric diaphragm. It may be that the moveable piezoelectric diaphragm is on an outer surface of the fluidic device.
[0031] The fluid may be extracellular fluid (e.g., interstitial skin fluid). The liquid may be a pharmaceutical fluid (e.g., medication / medicinal drugs such as antibiotics, insulin or vaccines). The fluid may comprise cannabinoids (e.g., cannabidiol). The fluid may comprise small molecule ingredients. The fluid may be ink (e.g., for printing).The substrate may comprise a silicon wafer. The substrate may be a semiconductor substrate.
[0032] It may be that the control circuity comprises CMOS control circuitry.
[0033] It may be that the control circuitry comprises a DSP circuit.
[0034] The CMOS control circuitry may be formed using conventional CMOS fabrication techniques (e.g. ion implantation, chemical vapour deposition (CVD), physical vapour deposition (PVD), etching, chemical-mechanical planarization (CMP) and / or electroplating).
[0035] The CMOS control circuitry may contain: transistors, diodes, resistors, capacitors, inductors, logic elements (e.g. flip-flops, latches, AND, OR, NOR, XOR gates) and / or memory elements (for example).
[0036] It may be that the fluidic device is not a microneedle device.
[0037] It may be that the height of the substrate is greater than 1 mm. It may be that the height of the substrate is greater than 3 mm. It may be that the height of the substrate is greater than 5 mm. It may be that the surface area of an upper surface of the substrate is greater than 1 mm2. It may be that the surface area of an upper surface of the substrate is greater than 5 mm2. It may be that the surface area of an upper surface of the substrate is greater than 10 mm2. It may be that the surface area of an upper surface of the substrate is greater than 25 mm2.
[0038] It may be that the first signal is received at the control circuitry. It may be that the first signal is generated by the movement of the at least one moveable piezoelectric diaphragm. It may be that the first signal is an electrical signal. It may be that the first signal is based on a measurement of the movement of the at least one moveable piezoelectric diaphragm.
[0039] The at least one moveable piezoelectric diaphragm may be actuatable using a drive signal (e.g., a drive signal generated by the control circuitry). The at least one moveable piezoelectric diaphragm may be actuatable by a drive signal prior togenerating the first signal. Alternatively, the at least one moveable piezoelectric diaphragm may generate the first signal without having been previously actuated using a drive signal.
[0040] The first signal is based on the movement of at least one moveable piezoelectric diaphragm of at least one of the one or more piezoelectric actuators. It may be that at least one of the one or more piezoelectric actuators is actuated using a drive signal. It may be that the oscillation of at least one moveable piezoelectric diaphragm of the at least one of the one or more piezoelectric actuators is dependent on the drive signal and at least one environmental and / or device characteristic. That is, the environmental and / or device characteristic modifies the oscillation of the membrane triggered by the drive signal. It may be that the fluidic device (e.g., using the control circuitry / first circuit) is configured to determine an indication of the environmental characteristic and / or an indication of the device characteristic based on the first signal and the drive signal. That is, information about the device / environment can be extracted by analysing the resultant oscillation of a moveable piezoelectric diaphragm because the device / environment characteristics will affect how the moveable piezoelectric diaphragm responds to a given drive signal.
[0041] The control circuitry may be connected to at least one of the piezoelectric actuators (e.g., at least one of the electrodes of the piezoelectric actuators) via one or more metallisation layers. The metallisation layers may comprise conductive connections. These conductive connections may be suitable for conducting digital or analogue information. These conductive connections may be suitable for conducting drive waveforms to actuate at least one of the piezoelectric actuators. These conductive connections may be suitable for conducting electrical signals from at least one of the piezoelectric actuators to the control circuitry (e.g., to a portion of the control circuitry that is associated with the sensing capabilities of the device).
[0042] It may be that the device characteristic is a characteristic of a fluid within a cavity of the device. For example, the pressure, the temperature, the presence of entrained air, or the viscosity of the fluid. It may be that the device characteristic is the presence (or absence) of a fluid in the cavity. It may be that the device characteristic is the state of at least one channel of the device (e.g., whether or not a channel is blocked). It may be that the device characteristic is a temperature of part of the device.It may be that the environmental characteristic is indicative of a characteristic of an external fluid. For example, the environmental characteristic may be any one of the pressure, temperature, viscosity, entrained air, or presence of an analyte within an external fluid. The external fluid may be a liquid. The external fluid may be a gas. The external fluid may be air.
[0043] It may be that the environmental characteristic is indicative of a first distance between a first part of the fluidic device and another object. It may be that the environmental characteristic is indicative of the humidity of the surroundings. It may be that the environmental characteristic is indicative of the pressure of the surroundings (e.g., the pressure of a surrounding fluid).
[0044] The fluidic device may be configured to generate the first signal whilst the pump is being actuated (e.g., the same fluidic device may be configured to provide concurrent sensing and pumping). The device may be configured to generate the first signal at a first time and actuate the pump at a second time different from the first time (e.g., the fluidic device may be configured to temporally interleave sensing and pumping functionalities).
[0045] It may be that the pump is one of a plurality of pumps, each pump comprising at least one piezoelectric actuator of the one or more piezoelectric actuators.
[0046] It may be that a first pump of the plurality of pumps is configured to pump (e.g., eject) a first fluid, and a second pump of the plurality of pumps is configured to pump (e.g., eject) a second fluid different from the first fluid.
[0047] Typically, the or each moveable piezoelectric diaphragm of the respective pump is configured to deform into the respective cavity to cause fluid movement.
[0048] It may be that the control circuitry is configured to receive the first signal. It may be that the control circuitry is integrally formed with the substrate.
[0049] Thus, control circuitry integrally provided within the device may be used for pumping and sensing functionalities. This facilitates a more compact, e.g., portable, arrangement.It may be that the control circuitry is distributed so that different portions of the control circuitry are formed at different locations within the substate. It may be that a portion of the control circuitry is external to the substrate (an external portion may be connected to at least one of the MEMS actuators via conductive connections). The control circuitry may comprise a first circuit and a second circuit. The first circuit may be configured to receive the first signal indicative of a device characteristic and / or indicative of an environmental characteristic. The first circuit may be integrated with the second circuit. It may be that the first circuit is configured to transmit signals to the second circuit. It may be that the first circuit is configured to receive signals from the second circuit. It may be that the first circuit is primarily associated with the sensing capabilities of the device and the second circuit is primarily associated with driving the piezoelectric actuators. It may be that the second circuit is configured to generate one or more driving signals to actuate the piezoelectric actuator of at least one pump. It may be that the second circuit is configured to generate one or more driving signals to actuate the piezoelectric actuator of at least one sensor. It may be that the first circuit comprises a DSP circuit. It may be that the second circuit is associated with (e.g., comprises) a switching circuit configured to control which piezoelectric actuator is actuated. For example, the pump may receive a first drive signal at a first time, and the sensor may receive a second drive signal at a second time different from the first time.
[0050] For example, it may be that the second circuit is configured to drive both at least one sensor and at least one pump. In particular, it is not necessary to integrate separate circuitry for driving the pump(s) and sensor(s). This further reduces the cost and complexity associated with device manufacture.
[0051] It may be that the fluidic device comprises a first sensor for generating the first signal, wherein the first sensor comprises a second piezoelectric actuator of the one or more piezoelectric actuators.
[0052] That is, it may be that the first sensor is separate from the pump.
[0053] Advantageously, this means that the sensor can be designed without any restrictions associated with providing pumping using the same actuator. The sensor design can be optimised for measurement of specific environmental / device characteristics. Further, using a different piezoelectric actuator compared to the first piezoelectric actuator for pumping means that the sensitivity of the sensor is not affected by anychannels / nozzles for fluid delivery and / or collection. It may be that the moveable piezoelectric diaphragm of the sensor is continuous (i.e., there are no channels through the moveable piezoelectric diaphragm to provide a fluid passage).
[0054] It may be that the piezoelectric membrane of the second piezoelectric actuator defines a wall of a cavity formed in the substrate, the piezoelectric membrane being configured to deform into the cavity. It may be that the cavity contains air (or another gas).
[0055] It may be that the first sensor is sealed from the environment. For example, it may be that fluid cannot enter or leave the cavity defined in part by the second piezoelectric actuator.
[0056] It may be that the sensor is not a pump. That is, it may be that the second piezoelectric actuator is not configured to pump fluid.
[0057] It may be that the sensor is not configured to be actuated by a drive signal.
[0058] It may be that the fluidic device comprises a plurality of sensors separate from the pump, wherein each of the plurality of sensors comprises at least one of the one or more piezoelectric actuators. Each of the sensors may be configured to generate a respective signal indicative of a device characteristic and / or an environmental characteristic. The control circuitry may be configured to receive the respective signals.
[0059] It may be that each of the plurality of sensors are arranged at different respective points around the pump on the substrate.
[0060] It may be that at least one sensor is arranged adjacent to the pump.
[0061] It may be that at least one of the one or more piezoelectric actuators is configured to generate a pressure wave (e.g., an ultrasound wave). It may be that the control circuitry is configured to control pressure wave transmission by controlling movement of the moveable piezoelectric diaphragm of the sensor. It may be that the control circuitry is configured to control pressure wave reception by receiving signals resulting from movement of the moveable piezoelectric diaphragm of the sensor.It may be that the fluidic device comprises MEMS metallisation layers comprising conductive connections for conducting signals between at least one piezoelectric actuator and the control circuitry (e.g., for conducting drive signals). It may be that the fluidic device comprises three or more MEMS metallisation layers. It may be that the fluidic device comprises four or more MEMS metallisation layers. It may be that the fluidic device comprises five or more MEMS metallisation layers. It may be that the fluidic device comprises greater than five MEMS metallisation layers.
[0062] It may be that the first sensor comprises a piezoelectric micromachined ultrasound transducer (PMLIT) element.
[0063] It may be that the control circuitry is configured to control ultrasound transmission by controlling movement of the moveable piezoelectric diaphragm of the sensor. It may be that the control circuitry is configured to control ultrasound reception by receiving signals resulting from movement of the moveable piezoelectric diaphragm of the sensor.
[0064] It may be that the fluidic device further comprises a first circuit, wherein the first circuit is configured to determine an indication of the environmental characteristic and / or an indication of the device characteristic based on the first signal.
[0065] Advantageously, the fluidic device may provide the functionality of providing a determination of an indication of an environmental characteristic or device characteristic based on the first signal on the same substrate. This is advantageous for a range of applications as described herein.
[0066] The fluidic device may be configured to determine indications of multiple different device characteristics. The fluidic device may be configured to determine indications of multiple different environmental characteristics.
[0067] It may be that the control circuitry comprises the first circuit.
[0068] It may be that the device characteristic and / or the environmental characteristic is one or more of:
[0069] a first distance;
[0070] a characteristic of a fluid;a humidity; or
[0071] a pressure.
[0072] The inventors have realised that it is possible to use sensed data to obtain characteristics of the environment of the fluidic device and / or the fluidic device itself, thereby facilitating improved device operation / performance.
[0073] It may be that the environmental characteristic is indicative of a first distance between a first part of the fluidic device and another object. At least one of the piezoelectric actuators may be configured to deform in response to a pressure wave (e.g., an ultrasound wave). The fluidic device may comprise a PMLIT element comprising at least one of the piezoelectric actuators (e.g., the sensor may comprise a PMLIT element). The fluidic device may comprise a plurality of PMLIT elements, each comprising at least one respective piezoelectric actuator.
[0074] It may be that a transmitted ultrasound wave is generated by driving at least one of the piezoelectric actuators. It may be that the fluidic device is configured to receive a received ultrasound wave using at least one of the piezoelectric actuators. The time taken between ultrasound transmission and reception can be used to calculate the first distance. The control circuitry may be configured to control ultrasound transmission. The control circuitry may be configured to control ultrasound reception. The control circuitry may be configured to determine the first distance.
[0075] The fluidic device may be an aerosoliser.
[0076] The fluidic device may be configured to determine an indication of a pressure. The fluidic device may be a nebuliser configured to generate an aerosol comprising droplets ejected from one or more pumps (typically a plurality of pumps). The fluidic device may be configured to determine an indication of a pressure within part of a housing of the nebuliser (e.g., within a mouthpiece).
[0077] It may be that the indication of an environmental characteristic and / or device characteristic is determined in dependence on an oscillation of at least one of the moveable piezoelectric diaphragms. It may be that the indication of an environmental characteristic and / or device characteristic is determined in dependence on a frequency of the oscillation. It may be that the indication of an environmental characteristic and / ordevice characteristic is determined in dependence on an attenuation of the oscillation. It may be that the indication of an environmental characteristic and / or device characteristic is determined in dependence on a phase of the oscillation. It may be that the indication of an environmental characteristic and / or device characteristic is determined in dependence on the power consumption of at least one of the piezoelectric actuators.
[0078] The inventors have realised that the oscillations of the moveable piezoelectric diaphragms (including the frequency content of those oscillations) can provide an indication of characteristics of the fluidic device and / or surrounding environment.
[0079] The first signal may comprise information indicative of the oscillation of at least one of the moveable piezoelectric diaphragms. It may be that the first signal comprises information indicative of at least one of an amplitude and a frequency of the oscillation.
[0080] For example, it may be that an indication that a cavity associated with pump is empty and / or contains entrained air is determinable based on an oscillation of the piezoelectric membrane defining at least part of a wall of that cavity.
[0081] It may be that the control circuitry is configured to generate an output signal based on the indication of the environmental characteristic and / or the indication of the device characteristic. It may be that the output signal is for controlling at least one of the one or more piezoelectric actuators. It may be that the output signal is for controlling the first piezoelectric actuator of at least one pump.
[0082] Thus, it is possible to control the fluidic device based on a characteristic of the device and / or the environment. Advantageously, this provides improved device performance. For example, an output signal indicative of a sensed distance could be used to trigger droplet ejection using the pump based on whether the intended target is an appropriate distance from the fluidic device. This is particularly advantageous for printing applications because the print quality is dependent on droplet speed at the target and path deviation of the droplet between the ejector and the target.
[0083] It may be that the fluidic device is configured to deliver fluid (e.g., eject droplets) onto an object comprising a surface having a first part and a second part. It may be that the first part is a first distance from the fluidic device (e.g., a first distance from a surfaceof the substrate on which the piezoelectric actuators are formed, along a direction perpendicular to the surface of the substrate). It may be that the second part is a second distance from the fluidic device (e.g., a second distance from a surface of the substrate on which the piezoelectric actuators are formed, along a direction perpendicular to the surface of the substrate). It may be that the first distance is different from the second distance. For example, the fluidic device may be configured to print onto a 3D shape having a curved / undulating surface.
[0084] The output signal may indicate that an environmental characteristic and / or device characteristic is within a predetermined range. The output signal may be indicative that an environmental characteristic and / or device characteristic has changed. The output signal may be indicative that an environmental characteristic and / or device characteristic is below a predetermined level. The output signal may be indicative that an environmental characteristic and / or device characteristic is above a predetermined level.
[0085] The fluidic device may be configured to determine an indication of a pressure. The fluidic device may be a nebuliser configured to generate an aerosol comprising droplets ejected from one or more pumps (typically a plurality of pumps). The fluidic device may be configured to determine an indication of a pressure within part of a housing of the nebuliser (e.g., within a mouthpiece). The output signal may be indicative of a pressure. The output signal may be for controlling at least one of the one or more piezoelectric actuators in response to the indication of the pressure. For example, the fluidic device may sense that the pressure within the mouthpiece has changed (e.g., due to inhalation / exhalation) and activate aerosol generation using the pump.
[0086] The fluidic device may be configured to determine an indication of a humidity. The fluidic device may be configured to determine an indication of a humidity of the environment. The output signal may be indicative of a humidity. The output signal may be for controlling at least one of the one or more piezoelectric actuators in response to the indication of the humidity. For example, the fluidic device may sense that the humidity of the surrounding has reduced below a predetermined level and activate aerosol generation using the pump.The control circuitry may be configured to accept the output signal as an input to a feedback control algorithm. The pump may be controlled based on an output from the feedback control algorithm.
[0087] For example, the fluidic device may be a humidifier that iteratively senses and adjusts the humidity using one or more pumps.
[0088] The output signal may be for controlling the fluidic device. The output signal may be used to control the speed of ejected fluid (e.g., droplets). The output signal may be used to control the volume of ejected fluid. The output signal may be used to control the charging of ejected fluid. The output signal may be used to switch at least one pump on. The output signal may be used to switch at least one pump off.
[0089] It may be that the fluidic device further comprises an additional sensor (e.g., a temperature sensor). It may be that the output signal is also based on a measurement made by the additional sensor.
[0090] It may be that the output signal is based on the position of at least one of the one or more piezoelectric actuators (e.g., the position of at least one of the one or more piezoelectric actuators that are generating a signal indicative of the device and / or environmental characteristic). It may be that the fluidic device control circuitry is configured to receive information indicative of the position of at least one of the one or more piezoelectric actuators. It may be that the fluidic device comprises a memory for storing data. The data may include information indicative of the positions of at least one or more piezoelectric actuators - for example, a database providing the relative positions of at least a subset of the one or more piezoelectric actuators. The control circuitry may be configured to receive information indicative of the position of at least one of the one or more piezoelectric actuators from the memory.
[0091] It may be that the fluidic device is configured to generate a second signal based on the movement of at least one moveable piezoelectric diaphragm of at least one of the one or more piezoelectric actuators, wherein the second signal is indicative of a further device characteristic and / or a further environmental characteristic. It may be that the fluidic device is configured to generate a first output signal based on the first signal, and a second output signal based on the second signal. It may be that the first signal is generated at a first time, and the second signal is generated at a second timedifferent from the first time. It may be that the fluidic device is configured to carry out a first action (e.g., actuate at least one pump) in response to the first output signal. It may be that the fluidic device is configured to carry out a second action (e.g., actuate at least one pump) in response to the second output signal. Accordingly, a multifunctional device is provided.
[0092] For example, it may be that fluidic device is configured to measure a user’s lung function (e.g., for lung volume / body plethysmography analysis) and to deliver medication. It may be that the first signal is indicative of a pressure within a portion of the device at a first time. It may be that the second signal is indicative of a pressure within a portion of the device at a second time. It may be that a first output signal is generated based on the first signal, and the fluidic device is configured to deliver medication (e.g., by actuation of a pump) in response to the first output signal. It may be that a second output signal is generated based on the second signal, and the fluidic device is configured to determine a quantity indicative of the user’s lung function (e.g., the control circuitry may be configured to determine an output indicative of the user’s lung volume). Accordingly, it is possible to provide a multi-functional device which can deliver medication and measure lung function (e.g., a multi-use inhaler).
[0093] It may be that the fluidic device is configured to generate a second signal based on the movement of at least one moveable piezoelectric diaphragm of at least one of the one or more piezoelectric actuators, wherein the second signal is indicative of a further device characteristic and / or a further environmental characteristic; and
[0094] wherein the fluidic device is configured to generate an output signal based on the first signal and the second signal. It may be that the output signal is for controlling at least one of the one or more piezoelectric actuators. It may be that the output signal is for controlling the piezoelectric actuator of at least one pump.
[0095] By generating a control signal based on a first and second signal it is possible to provide a device that can respond to various environmental / device characteristics or changes in an environmental / device characteristics over time. This improved functionality is advantageous for a range of applications as described herein.
[0096] It may be that the further device characteristic and / or a further environmental characteristic relate to the same quantity (e.g., distance, pressure, humidity, fluid property) as the device characteristic and / or an environmental characteristicassociated with the first signal. It may be that the further device characteristic and / or a further environmental characteristic relate to the same quantity (e.g., distance, pressure, humidity, fluid property) as the device characteristic and / or the environmental characteristic associated with the first signal but at a different time. That is, it may be that the first signal is generated at a first time, and the second signal is generated at a second time different from the first. It may be that the further device characteristic and / or a further environmental characteristic relate to a different quantity (e.g., distance, pressure, humidity, fluid property) compared to the device characteristic and / or the environmental characteristic associated with the first signal.
[0097] For example, the first signal may be indicative of a first distance between a first part of the fluidic device and first part of an object, and the second signal may be indicative of a second distance between a second part of the fluidic device and second part of an object. The fluidic device (e.g., the control circuitry) may be configured to compare the first distance and the second distance and determine an indication of the orientation of the fluidic device relative to a surface of the object - e.g., to determine if the fluidic device is parallel with the surface. The output signal may be based on the orientation of the fluidic device - e.g., the pump will only be actuated if the fluidic device is level with surface of the object. It may be that the fluidic device is configured to compare the first distance and the second distance to determine an indication of the texture of the object.
[0098] Further, the device can respond to changes in various environmental / device characteristics based on the first signal and the second signal - e.g., changes in humidity and / or pressure.
[0099] It may be that the first signal is generated based on the movement of a first moveable piezoelectric diaphragm of at least one of the one or more piezoelectric actuators, and the second signal is generated based on the movement of a second moveable piezoelectric diaphragm different from the first moveable piezoelectric diaphragm.
[0100] According to another aspect of the invention there is provided a fluidic droplet ejection system comprising one or more fluidic devices as described herein.
[0101] It may be that the fluidic droplet ejection system comprises a nebuliser, or an inkjet printer module, or a fluid mixing module, or a humidifier.According to another aspect of the invention there is provided a method of using any of the fluidic devices or systems as described herein, comprising receiving a first signal indicative of a device characteristic and / or an environmental characteristic.
[0102] The method may comprise controlling the fluidic device or system based on the first signal.
[0103] The method may comprise controlling at least the first piezoelectric actuator based on the first signal.
[0104] The method may further comprise determining an indication of the device characteristic and / or the environmental characteristic (e.g., using the control circuitry).
[0105] The method may comprise actuating at least one of the one or more piezoelectric actuators using a drive signal. It may be that the method comprises determining an indication of the environmental characteristic and / or an indication of the device characteristic based on the first signal and the drive signal.
[0106] According to another aspect of the invention there is provided a method of manufacturing any of the fluidic devices or systems as described herein, the method comprising:
[0107] providing a substrate;
[0108] providing control circuitry; and
[0109] forming one or more piezoelectric actuators on the substrate.
[0110] According to another aspect of the invention there is provided a liquid suitable for any of the fluidic devices or systems as described herein.
[0111] The present invention extends to any of the fluidic devices described hereinbefore, comprising the liquid.
[0112] According to another aspect of the invention there is provided computer program code or semiconductor fabrication instructions which, when executed by a processor or executed as semiconductor fabrication steps, create any of the devices or systems as aforesaid.Although the embodiments described above (and below) with reference to the drawings may comprise computer-related methods or apparatus, the invention may also extend to program instructions, particularly program instructions on or in a carrier, adapted for carrying out the processes of the invention or for causing a computer to perform as the computer apparatus of the invention. Programs may be in the form of source code, object code, a code intermediate source, such as in partially compiled form, or any other form suitable for use in the implementation of the processes according to the invention. The carrier may be any entity or device capable of carrying the program instructions.
[0113] Thus, there is specifically provided in a further aspect of the invention a non-transitory computer readable medium encoding computer program code which, when executed on at least one processor of a computer, causes the computer (or any appropriate combination of computers, with appropriate distribution of the computer program code) to carry out any appropriate method as aforesaid.
[0114] For example, the carrier may comprise a storage medium, such as a magnetic recording medium, for example a solid state disk or hard disk, or flash memory, optical memory, and so on. Further, the carrier may be a transmissible carrier such as an electrical or optical signal which may be conveyed via electrical or optical cable or by radio or other means. When a program is embodied in a signal which may be conveyed directly by cable, the carrier may be constituted by such cable or other device or means.
[0115] Features, integers, characteristics, or groups described in conjunction with a particular aspect are to be understood to be applicable to any other aspect described herein unless incompatible therewith. It will be understood that all of the features and / or all of the steps of any aspect disclosed hereinabove may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive.Description of the Drawings
[0116] An example embodiment of the present invention will now be illustrated with reference to the following Figures in which:
[0117] Figure 1A and Figure 1B are schematic representations of a fluidic device according to an embodiment of the invention;
[0118] Figure 2 is a schematic representation of a fluidic device according to an embodiment of the invention;
[0119] Figure 3 is a schematic representation of a fluidic device according to an embodiment of the invention;
[0120] Figure 4 is a flowchart illustrating a method of manufacturing a fluidic device according to an embodiment of the invention;
[0121] Figures 5A-5E are schematic representations of a method of manufacturing a fluidic device according to an embodiment of the invention;
[0122] Figures 6A-6E are schematic representations of a method of manufacturing a fluidic device according to an embodiment of the invention;
[0123] Figure 7 is a flowchart illustrating a method of using a fluidic device according to an embodiment of the invention; and
[0124] Figure 8 is a schematic representation of part of the circuitry of a fluidic device according to an embodiment of the invention.
[0125] Detailed Description of an Example Embodiment
[0126] Figure 1A and Figure 1B are schematic representations of a fluidic device 100 having a pump 101 and a sensor 103. The pump 101 comprises a first piezoelectric actuator formed on a substrate 105 and the sensor 103 comprises a second piezoelectric actuator formed on the substrate 105.
[0127] CMOS control circuitry 107 comprising a plurality of transistors is integrally formed with the substrate 105, and electrically couped to both piezoelectric actuators via conductive connections. The CMOS metallisation layers 109 and MEMS metallisation layers 111 are used to provide electrical connection between elements of the device and each comprise a portion of the conductive connections.The first piezoelectric actuator comprises a moveable piezoelectric diaphragm including a piezoelectric body 113, a first electrode 115 and a second electrode 117. The second piezoelectric actuator also comprises a moveable piezoelectric diaphragm including a piezoelectric body 119, a first electrode 121 and a second electrode 123.
[0128] Each moveable piezoelectric diaphragm also includes a portion of the additional layer 125 (made from the same material as the rest of the substrate 105, in this embodiment) and a portion of a protective layer 127.
[0129] A first cavity 133 associated with the first piezoelectric actuator is defined in part by the respective moveable piezoelectric diaphragm and in part by the substrate 105. A second cavity 135 associated with the second piezoelectric actuator is defined in part by the respective moveable piezoelectric diaphragm and in part by the substrate 105.
[0130] Deep trench isolation (DTI) rings 129 and a buried oxide (BOX) layer 131 are also provided.
[0131] A channel 137 is defined through the centre of the moveable piezoelectric diaphragm of the first piezoelectric actuator. By comparison, the moveable piezoelectric diaphragm of the second piezoelectric actuator is continuous. The sensor 103 is sealed from the surroundings so that fluid above the protective layer 127 cannot enter the second cavity 135.
[0132] In use, fluid 139 is pumped from the first cavity 133 via the channel 137 by deformation of the respective moveable piezoelectric diaphragm. The CMOS control circuitry 107 is configured to generate a drive signal to cause the movement of the moveable piezoelectric diaphragm of the first piezoelectric actuator- e.g., to cause pumping. Typically, the drive signal causes a temporally varying potential difference to be applied over the piezoelectric body 113 causing oscillation of the moveable piezoelectric diaphragm, which is turn causes droplets to be ejected via the channel 137.
[0133] Further, in use, the moveable piezoelectric diaphragm of the sensor 103 is configured to deform into the second cavity 135. The CMOS control circuitry 107 is configured to receive electrical signals generated by the movement of the moveable piezoelectric diaphragm of the sensor 103. In this embodiment, the sensor 103 is configured to generate an electrical signal in response to pressure waves 141.Accordingly, a highly integrated device having both pumping and sensing capabilities is provided. This is advantageous in a range of applications which require pumping of fluid. For example, in fluid mixing modules where the fluid within the cavity 133 is delivered into a second fluid, the pumping may be controlled based on the pressure of the second fluid. This is also helpful in medical devices such as nebulisers where the pressure inside part of the housing will change due to the user’s exhalation / inhalation, and the pumping may be controlled based on a sensed pressure or change in pressure.
[0134] Figure 2 is a schematic representation of a fluidic device 200 having a plurality of pumps 201A-C. In this embodiment, each pump 201A-C is a droplet ejector. In use, each of the droplet ejectors are configured to eject droplets to generate an aerosol.
[0135] Each droplet ejector 201A-C is formed on the substrate 205. Each droplet ejector 201A-C comprises a moveable piezoelectric diaphragm including a respective piezoelectric body 213A-C, a respective first electrode 215A-C and a second electrode 217A-C. A channel 237A-C is provided through each respective moveable piezoelectric diaphragm. In use, fluid is pumped from each cavity 233A-C through each respective channel 237A-C.
[0136] The fluidic device 200 also includes a protective layer 227 and an additional layer 225. CMOS metallisation layers 209 and MEMS metallisation layers 211 are provided at least in part within the additional layer. CMOS control circuitry 207 is formed within the substrate 205. As shown, this control circuitry may be distributed in multiple locations within the substrate.
[0137] The fluidic device 200 further comprises a sensor 203. The sensor comprises a moveable piezoelectric diaphragm including a piezoelectric body 219, a first electrode 221 and a second electrode 223. One wall of the cavity 235 is defined by the moveable piezoelectric diaphragm of the sensor, and the other walls are defined by the substrate 205. The sensor comprises a sealed channel 243 - in this embodiment the channel is filled with benzocyclobutene (BOB).
[0138] Deep trench isolation (DTI) rings 229 and a buried oxide (BOX) layers 231 are also provided.In use, the moveable piezoelectric diaphragm of the sensor 203 deforms in response to a change in pressure of the surroundings. The deformation of the piezoelectric body 219 causes an electrical signal to be generated. This signal is received by a first circuit of the CMOS control circuitry 207. The first signal is configured to determine an indication of the pressure of the surrounding and send a subsequent signal based on this indication to a second circuit of the CMOS control circuitry 207. The second circuit generates a driving signal for driving each of the droplet ejectors 201 A-C in response to reception of the subsequent signal. Thereby, droplet ejection can be controlled in response to a sensed quantity using the sensor 203, pumps 201A-C and CMOS circuitry 207 each associated with the same substrate.
[0139] Figure 3 is a schematic representation of a portion of a printhead 300 having a plurality of pumps 301A-B and a plurality of PMLIT sensors 303A-B. In this embodiment, each pump 301 A-B is a droplet ejector for ejecting ink.
[0140] Each of the pumps 301A-B and PMLIT sensors 303A-B are formed on a substate 305. Similarly to the fluidic device 200 shown in Figure 2, the printhead 300 comprises a protective layer 327, an additional layer 325, CMOS metallisation layers 309, MEMS metallisation layers 311, DTI rings 329 and BOX layers 331. Each droplet ejector 301 A-B comprises a moveable piezoelectric diaphragm including a respective piezoelectric body 313A-B, a respective first electrode 315A-B and a second electrode 317A-B. A channel 337A-B is provided through each respective moveable piezoelectric diaphragm in fluid communication with a respective cavity 333A-B. Each PMLIT sensor 303A-B comprises a moveable piezoelectric diaphragm including a respective piezoelectric body 319A-B, a respective first electrode 321A-B and a second electrode 323A-B. The moveable piezoelectric diaphragm of each PMLIT sensor 303A-B is configured to deform into a respective cavity 335A-B.
[0141] In use, the CMOS control circuitry 307 is configured to generate drive signals for driving the PMLIT sensors 303A-303B. These drive signals are transmitted via the CMOS and MEMS metallisation layers 309, 311 to the piezoelectric actuators of the sensors 303A-303B. The PMLIT sensors 303A-303B are configured to transmit ultrasound pulses in response to the drive signals. The PMLIT sensors 303A-303B are configured to receive ultrasound pulses reflected from an object (e.g., typically a sheet of paper) arranged in the path of the transmitted ultrasound pulses. The received ultrasound pulses cause the moveable piezoelectric membranes of the sensors to deform, generatingrespective first signals which are received by the CMOS circuitry 307. The CMOS circuitry 307 is configured to compare the signals received by different PMLIT sensors 303A-303B and generate an output signal which is indicative of whether a sheet of paper, for example, is level with the plane of a surface 349 of the printhead. The CMOS circuitry 307 is configured to generate driving signals to drive the droplet ejectors 301 A-B if the output signal is indicative of the sheet of paper being sufficiently level with the surface 349. Accordingly, ink ejection can be selectively triggered using integrated sensing capabilities.
[0142] Figure 4 is a schematic representation of a method 400 of manufacturing a fluidic device according to an embodiment of the invention. The method involves a step of providing a substrate 410, a step of forming control circuitry 420 and a step of forming piezoelectric actuators 430. The step of forming control circuitry 420 typically involves forming a plurality of transistors using standard CMOS processing methodologies including ion implantation. The step of forming the piezoelectric actuators 430 involves forming each moveable piezoelectric diaphragms by depositing the respective electrodes and intervening piezoelectric body. Typically, this step involves using successive thin film deposition techniques. Preferably, each piezoelectric body is formed of a material such as AIN or ScAIN which may be deposited at a temperature below 450°C by physical vapour deposition (including low-temperature sputtering). The electrodes are formed of, for example titanium, platinum, aluminium, tungsten or alloys thereof.
[0143] Figures 5A-E provide schematic representations of a method of manufacturing a fluidic device.
[0144] Figure 5A shows the step of providing a substrate 505 together with the step of forming the CMOS control circuitry 507. In this case, the substrate is a silicon wafer and the CMOS control circuitry comprises a plurality of transistors. DTI rings 529 and a BOX layer 531 are also formed. Typically, the BOX layer is formed using ion implantation of oxygen into the substate and the DTI rings are formed using an etching process.
[0145] Figure 5B shows the step of forming the additional layer 525 together with deposition of the CMOS metallisation layers 509. Two layers of CMOS metallisation are used in this example, although additional layers would also be possible.Figure 5C shows the step of forming a first electrode 515, a second electrode 517 and piezoelectric body 513 of a pump and a first electrode 521, a second electrode 523 and piezoelectric body 519 of a sensor. The MEMS metallisation layers 511 which provide electric connection to the piezoelectric actuators are also formed. There is also a step of depositing a protective layer 527 above the MEMS components.
[0146] Figure 5D shows the step of etching the channel 537 from the front side of the substrate. This can be done using a conventional etch process.
[0147] Figure 5E shows the step of forming the cavity 533 of the pump and the cavity 535 of the sensor by etching from the backside of the substrate (e.g., by using a DRIE etch procedure).
[0148] Figures 6A-E provide schematic representations of another method of manufacturing a fluidic device comprising a pump and a sensor.
[0149] Figure 6A shows the steps of providing a substrate 605, forming the CMOS control circuitry 607, the DTI rings 629 and the BOX layer 631. Figure 6B shows the step of forming an additional layer 625 together with deposition of the CMOS metallisation layers 609. Figure 6C shows the step of forming a first electrode 615, a second electrode 617 and piezoelectric body 613 of a pump and a first electrode 621 , a second electrode 623 and piezoelectric body 619 of a sensor. The MEMS metallisation layers 611 and protective layer 627 are also deposited.
[0150] A difference between the method shown in Figures 5A-5E and the method shown in Figures 6A-6E is that annular electrodes and piezoelectric bodies are used for both the sensor and the pump (instead of just for the pump). Figure 6D shows the step of forming the channel 637 through the moveable piezoelectric diaphragm of the pump. A channel 643 is also formed through the moveable piezoelectric diaphragm of the sensor.
[0151] This means that, as shown in Figure 6E, the cavity 635 of the sensor may be formed by etching from the frontside of the substrate via the channel. The channel 643 may then be filled. The cavity 633 of the pump is formed by carrying out an etch procedure from the frontside of the substrate.Figure 7 is a flowchart illustrating a method 700 of using a fluidic device according to an embodiment of the invention. The method 700 comprises a step 710 of receiving a first signal which is indicative of a device characteristic and / or an environmental characteristic. The method also comprises a step 720 of controlling the fluidic device based on the first signal. For example, as discussed in relation to Figures 1A-1B, the method may involve receiving a first signal which is indicative of a surrounding pressure. A drive signal may be generated in response to this first signal to cause actuation of a pump of the fluidic device.
[0152] Figure 8 is a schematic representation of part of the circuitry of a fluidic device according to an embodiment of the invention. The fluidic device comprises a pump having a first electrode 815 and a second electrode 817, and a sensor comprising a first electrode 821 and a second electrode 823. The fluidic device is configured to transmit and receive pressure waves 841 using the sensor. The fluidic device further comprises a first CMOS circuit 807a and a second CMOS circuit 807b. In this embodiment, both are integrally formed within a substrate of the device. MEMS metallisation layers 809b electrically connect the first electrode 815, 821 and second electrodes 817, 823 of the sensor and pump to the second CMOS circuit 807b. The second CMOS circuit is configured to conduct drive signals to these electrodes - e.g., to cause the pump to eject fluid and the sensor to generate pressure waves. That is, the second circuit 807b is configured to drive both the sensor and the pump. The first electrode 821 and the second electrode 823 of the sensor are electrically connected to the first CMOS circuit 807a via MEMS metallisation layers 809a. The first circuit is configured to receive electrical signals generated by pressure waves 841 incident on the sensor. The first CMOS circuit 807a is configured to determine an indication of characteristics of the surroundings of the fluidic device using the electrical signals generated by the pressure waves 841. That is, the first CMOS circuit 807a is primarily associated with the sensing capabilities of the fluidic device.
[0153] Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to”, and they are not intended to and do not exclude other components, integers, or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.Features, integers, characteristics, or groups described in conjunction with a particular aspect, embodiment, or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.
Claims
1. 28Claims1. A fluidic device comprising:a substrate;one or more piezoelectric actuators formed on the substrate, each of the piezoelectric actuators comprising a moveable piezoelectric diaphragm;a pump comprising a first piezoelectric actuator of the one or more piezoelectric actuators;control circuitry electrically coupled to the pump, wherein the control circuitry is configured to actuate the first piezoelectric actuator to cause movement of a fluid;wherein the fluidic device is configured to generate a first signal indicative of a device characteristic and / or indicative of an environmental characteristic, wherein the first signal is based on the movement of at least one moveable piezoelectric diaphragm of at least one of the one or more piezoelectric actuators.
2. The fluidic device of claim 1 wherein the pump is one of a plurality of pumps, each pump comprising at least one piezoelectric actuator of the one or more piezoelectric actuators.
3. The fluidic device of claim 1 or claim 2 wherein the control circuitry is configured to receive the first signal and / or wherein the control circuitry is integrally formed with the substrate.
4. The fluidic device according to any preceding claim, wherein the fluidic device comprises a first sensor for generating the first signal, wherein the first sensor comprises a second piezoelectric actuator of the one or more piezoelectric actuators.
5. The fluidic device according to claim 4 wherein the first sensor comprises a piezoelectric micromachined ultrasound transducer (PMLIT) element.
6. The fluidic device according to any preceding claim further comprising a first circuit, wherein the first circuit is configured to determine an indication of the environmental characteristic and / or an indication of the device characteristic based on the first signal.
7. The fluidic device according to claim 6 wherein the control circuitry comprises the first circuit.
8. The fluidic device according to any preceding claim, wherein the device characteristic and / or the environmental characteristic is one or more of: a first distance;a characteristic of a fluid;a humidity; ora pressure.
9. The fluidic device according to any of claims 6-8, wherein the control circuitry is configured to generate an output signal based on the indication of the environmental characteristic and / or the indication of the device characteristic, and optionally wherein the output signal is for controlling at least one of the one or more piezoelectric actuators, and optionally wherein the output signal is for controlling the first piezoelectric actuator of at least one pump.
10. The fluidic device according to any of claims 1-8 wherein the fluidic device is configured to generate a second signal based on the movement of at least one moveable piezoelectric diaphragm of at least one of the one or more piezoelectric actuators, wherein the second signal is indicative of a further device characteristic and / or a further environmental characteristic; and wherein the fluidic device is configured to generate an output signal based on the first signal and the second signal, andoptionally wherein the output signal is for controlling at least one of the one or more piezoelectric actuators, andoptionally wherein the output signal is for controlling the piezoelectric actuator of at least one pump.
11. The fluidic device according to claim 10 wherein the first signal is generated based on the movement of a first moveable piezoelectric diaphragm of at least one of the one or more piezoelectric actuators, and the second signal is generated based on the movement of a second moveable piezoelectric diaphragm different from the first moveable piezoelectric diaphragm.
12. The fluidic device according to any one preceding claim, wherein the fluidic device is configured to generate a first signal indicative of an environmental characteristic.
13. The fluidic device according to claim 12, wherein the pump is controlled based on the measurement of an environmental characteristic using the control circuitry.
14. The fluidic device according to claim 12 or claim 13, wherein the environmental characteristic is indicative of a characteristic of an external fluid, or a first distance between a first part of the fluidic device and another object.
15. A fluidic droplet ejection system comprising one or more fluidic devices according to any preceding claim, optionally wherein the fluidic droplet ejection system comprises a nebuliser, or an inkjet printer module, or a fluid mixing module, or a humidifier.
16. A method of using any of the fluidic devices according to claims 1-14 or systems according to claim 15 comprising receiving a first signal indicative of a device characteristic and / or an environmental characteristic, and controlling the fluidic device or system based on the first signal.
17. A method of manufacturing a fluidic device according to any of claims 1-14, or systems according to claim 15, the method comprising:providing a substrate;providing control circuitry; andforming one or more piezoelectric actuators on the substrate.
18. A liquid suitable for any of the fluidic devices according to claims 1-14, or systems according to claim 15.