Sensor arrangement and method for detecting a quantity or concentration of a target fluid in a medium using the sensor arrangement

Abstract

Sensor arrangement (100) comprising: a first micropump (10) which has a normally closed (NC) safety valve (11), a second micropump (20) which has a normally closed (NC) safety valve (21), wherein the first micropump (10) and the second micropump (20) are arranged in a fluidic series connection and have the same fluid pumping direction, and a sensor (30) having a sensor chamber (31) with a sensor element (32) in the sensor chamber (31), wherein the sensor (30) is configured to provide a sensor output signal (S) OUT ) based on a condition of a fluid (F) in the sensor chamber (31), wherein the sensor chamber (31) of the sensor (30) is fluidically coupled between the first and the second micropump (10, 20) and wherein the first and second micropump (10, 20) are configured to provide a defined operating mode of the sensor arrangement (100) based on the respective activation condition of the first and second micropump (10, 20) to provide (1.) a defined negative fluid pressure in the sensor chamber (31), (2.) a defined positive fluid pressure in the sensor chamber (31) or (3.) a defined fluid flow through the sensor chamber (31).

Description

Technical field

[0001] Embodiments of the present invention relate to a sensor arrangement and a method for detecting the quantity or concentration of a target fluid in a medium using the sensor arrangement. More specifically, embodiments relate to a micropump with a gas sensor and, in particular, a fluid concept using micropumps with a safety valve for a gas sensor.

[0002] Gas sensors can detect molecules through an interaction between the molecule and a sensitive sensor layer. The process of adsorption and desorption of different gas molecules with the sensor layer affects the sensitivity, specificity, and drift of the gas sensor. These adsorption and desorption mechanisms can be influenced, for example, by heating the sensor layer, which generally increases the desorption of molecules. A pump or micropump can assist these processes by transporting gas molecules to or from the sensor layer in a controlled manner.

[0003] Reducing the gas pressure in the sensor chamber of the pump or micropump can support the regeneration of the sensor layer, e.g., the removal (= desorption) of gas molecules from the sensor layer. Technical background

[0004] The detection of environmental parameters in the surrounding atmosphere, such as ambient gas components, is becoming increasingly important with the implementation of suitable sensors that can be used in mobile devices.

[0005] For example, WO 2015 104 221 A1 relates to a gas measuring device with a sensor unit for detecting a gas. The sensor unit includes a pressure-tight measuring channel, a gas inlet for introducing the gas into the measuring channel, a gas outlet for releasing the gas from the measuring channel, and a pump unit for evacuating the measuring channel. The measuring channel has a gas sensor for detecting the gas and a heating unit for heating the gas sensor. The sensor unit can be operated in a measuring mode and a regeneration mode, whereby in the regeneration mode the measuring channel is evacuated and the gas sensor is heated.

[0006] Thus, a pump, together with an active valve, generates negative pressure in the chamber (the measuring channel) at the sensor layer to assist the gas sensor during regeneration. A heating element is also implemented to heat the gas sensor for regeneration. The negative pressure (relative to atmospheric pressure), along with the heating, is intended to improve sensor regeneration.

[0007] US 2009 / 0185955A1 relates to a microfluidic device for molecular diagnostic applications, comprising: - a substrate with a surface on which at least one microchannel structure is located; - at least one detection, control, and / or processing element; - at least one receiving chamber for receiving the liquid sample, wherein the receiving chamber can be formed between a membrane and the substrate, the receiving chamber being in fluid communication with at least one microchannel; - at least one membrane, wherein the membrane covers the top surface of at least one microchannel structure arranged on the substrate in a leak-proof manner, whereby movement of the membrane causes a pumping action on the liquid located in the microchannel in the receiving chamber and / or a valve action on the liquid passing through the microchannel;and - at least one device for actuating the movement of the diaphragm, comprising pressure and / or vacuum generating means.;

[0008] US Patent 2005 / 0214863 A1 relates to a method and system for analyzing saliva using a sensor array, a light source, and a detector. The sensor array consists of a carrier element in which a plurality of cavities may be formed. In one embodiment, a series of chemically sensitive particles are positioned in the cavities.

[0009] However, the known state of the art has a number of disadvantages and limitations.

[0010] In general, a large dead volume in the gas pump at the sensor chamber has the disadvantage that a large and powerful pump is needed to generate the desired pressure, e.g., a negative pressure, within a specific time or to produce the higher flow rate required to purge the dead volume. Furthermore, active valves move a changing volume when they move the gas.

[0011] Known gas sensor implementations therefore have a large and bulky design. Such designs are difficult to implement in mobile devices. Furthermore, these gas sensors have a large dead volume when transporting the gas to and from the sensor chamber. Additionally, with a pump and an active valve, only either negative pressure (pump before and valve after the sensor chamber) or positive pressure (pump after and valve before the sensor chamber) is achievable.

[0012] In general, there is a need in the field of gas sensors for the provision of an improved concept for gas sensors that can be easily integrated into mobile devices.

[0013] Such a need can be met by the sensor arrangement according to claim 1 and the method for detecting a quantity or concentration of a target fluid in a medium according to claim 25.

[0014] Furthermore, specific implementations of the sensor arrangement and the method are defined in the dependent claims. Summary

[0015] According to one embodiment, a sensor arrangement comprises: a first micropump, e.g., a microfluidic or peristaltic pump, which has a normally closed (NC) safety valve, e.g., at the micropump outlet; a second micropump, e.g., a microfluidic or peristaltic pump, which has a normally closed (NC) safety valve, e.g., at the micropump outlet; and a sensor comprising a sensor chamber, e.g., a sensor cavity or a sensor volume, with a sensor element, e.g., an active sensitive region or layer, in the sensor chamber, wherein the sensor is configured to provide a sensor output signal based on a condition of the fluid, e.g., a gas or liquid, in the sensor chamber.The sensor chamber of the sensor is fluidically coupled between the first and the second micropump, and the first and the second micropump are configured to provide a defined operating mode of the sensor arrangement based on the respective activation or operating condition of the first and the second micropump to provide (1) a defined negative fluid pressure in the sensor chamber, (2) a defined positive fluid pressure in the sensor chamber, or (3) a defined fluid flow, e.g., fluid throughput, through the sensor chamber.

[0016] The present concept according to the invention for a sensor arrangement and for detecting the quantity or concentration of a target fluid in a medium is based on the finding that the sensor arrangement comprises two micropumps, e.g., two microfluidic or peristaltic pumps, each with a normally closed safety valve, wherein the fluid sensor, e.g., a gas or liquid sensor, is arranged in a sensor chamber that is fluidically coupled between the two micropumps and is otherwise sealed against the environment. Since the two micropumps are arranged in a fluidic series connection and have the same fluid pumping direction, both a negative and a positive fluid pressure can be generated in the sealed sensor chamber.

[0017] Based on this implementation of the sensor arrangement, a compact solution for the gas sensor can be achieved, whereby the sensor arrangement can realize either negative or positive pressures in the sensor chamber in a design that is as small and flat as possible and can also be easily integrated into mobile devices.

[0018] According to a further embodiment, the first micropump has a pump inlet, a pump chamber and a pump outlet, wherein the first micropump is configured to pump the fluid, e.g. ambient air, from the pump inlet through the pump chamber to the pump outlet, wherein the second micropump has a pump inlet, a pump chamber and a pump outlet, wherein the second micropump is configured to pump the fluid from the pump inlet through the pump chamber to the pump outlet, and wherein the sensor chamber is fluidically coupled between the pump outlet of the first micropump and the pump inlet of the second micropump and is otherwise sealed against the environment, e.g. hermetically sealed or closed.

[0019] The sensor assembly thus features a sealed or enclosed sensor chamber. During measurement, the enclosed sensor chamber provides a defined sensor volume that is isolated from the surrounding atmosphere outside the gas sensor. This prevents interfering convection when the micropumps are switched off, resulting in optimal conditions for gas measurement.

[0020] According to one embodiment, the first and second micropumps, the sensor, and the processing device can be integrated with a semiconductor substrate, e.g., a silicon substrate. Integrating the sensor assembly (or at least substantial portions thereof) into a semiconductor substrate allows for a relatively small dead volume of the micropumps, on the order of a few microliters, e.g., between 1 and 10 microliters. Based on this relatively small dead volume, the measurement time and accuracy of the fluid sensor can be accelerated (increased), and the calibration of this fluid sensor can also be significantly improved. Furthermore, if sharp corners or edges in the fluid channels of the fluid sensor can be (at least partially) avoided, dispersion of the fluid or fluid particles flowing through the fluid sensor can be prevented (minimized) or at least reduced.

[0021] According to the first operating mode of the sensor arrangement, a vacuum mode can be implemented in the sensor chamber by means of the first and second micropumps. In the first operating mode, the first micropump is in an off state, e.g., switched off or deactivated, and the second micropump is in an on state, e.g., switched on, activated, or powered to provide the defined negative fluid pressure in the sensor chamber.

[0022] The second micropump can be optimized to provide a high negative pressure (relative to atmospheric or ambient pressure). When a high negative pressure is achieved, the sensor array can be calibrated very effectively, for example, in combination with heating the fluid sensor element, such as a gas detection membrane.

[0023] According to a second operating mode of the sensor arrangement, an overpressure mode can be implemented in the sensor chamber using the first and second micropumps. In this second operating mode, the first micropump is in an on state, and the second micropump is in an off state, in order to provide the defined positive fluid pressure in the sensor chamber.

[0024] The first micropump can be optimized to provide a high positive pressure. An optional pressure sensor can, for example, measure the pressure in the sensor chamber as a reference value for sensor readout and as feedback to set a specific pressure in the sensor chamber. Furthermore, a high or increased pressure in the sensor chamber can enhance the process of binding the target fluid to the sensor element within the chamber. Integrating a pressure sensor, such as a piezoelectric element, into the sensor chamber allows for pressure control and enables highly accurate measurements.

[0025] According to a further embodiment, the second operating mode can have a first partial operating mode and a subsequent second partial operating mode, wherein, in the first partial operating mode, the first micropump is in an on state and the second micropump is in an off state to provide the defined positive fluid pressure in the sensor chamber. In the (immediately) subsequent second partial operating mode, the first micropump is switched to an off state, and the second micropump is held in the off state to provide a defined quantity of fluid, i.e., a defined fluid volume or defined measurement volume, in the sensor chamber, e.g., within the fluid path and the sensor chamber. Thus, the sensor element can interact with a defined quantity of the "charged" fluid introduced into the sensor chamber.

[0026] According to a third operating mode of the sensor assembly, a purging mode can be implemented in the sensor chamber using the first and second micropumps. In this third operating mode, the first and second micropumps are both on to provide a defined fluid flow, e.g., with a defined fluid throughput, through the sensor chamber. The purging mode of the sensor assembly can provide effective calibration, e.g., again in combination with heating the fluid sensor element.

[0027] According to another embodiment, the sensor arrangement can have a pressure sensor in the sensor chamber, or fluidically coupled to the sensor chamber, for measuring a fluid pressure in the sensor chamber.

[0028] If the pressure at the sensor element, e.g., the gas sensor layer, is adjustable, this feature can be generally used to obtain more specific sensor feedback. More precisely, gas measurement at certain pressure levels leads to gas molecule-specific binding to the sensor element, thus enabling specific gas measurement. The provision of the pressure sensor therefore allows the pressure at a sensor element (a gas sensor membrane) to be changed, so that a pressure-dependent fluid (gas) absorption profile can be detected.

[0029] According to a further embodiment, the first micropump can have several micropump elements in a cascaded arrangement, e.g. fluidically connected in series, to provide an increased positive fluid pressure in the sensor chamber, and / or be fluidically connected in parallel to provide an increased fluid flow rate through the sensor chamber.

[0030] According to another embodiment, the second micropump can have several micropump elements in a cascaded arrangement to provide an increased negative fluid pressure in the sensor chamber and / or an increased fluid flow rate through the sensor chamber.

[0031] According to a further embodiment, the sensor arrangement can (alternatively or additionally) include a heating element in the sensor chamber, or thermally coupled to the sensor chamber, for heating the fluid, e.g., adjusting the temperature of the fluid, in the sensor chamber and / or the sensor element of the sensor. Thus, the heating element can provide different measurement temperatures in the sensor chamber. Furthermore, the heating element can provide or at least support a "reset" (a regeneration or restoration) of the sensor element, e.g., the active sensor region.

[0032] According to another embodiment, the sensor arrangement can have a temperature sensor in the sensor chamber, or thermally coupled to the sensor chamber, for measuring the temperature in the sensor chamber.

[0033] As stated above, a pressure-dependent fluid (gas) absorption profile can be detected, whereby the provision of a temperature sensor and / or heating device can ensure temperature control of the fluid in the sensor chamber. Based on a controlled temperature and pressure in the sensor chamber, a temperature / pressure matrix measurement enables the detection of specific molecules from this matrix, e.g., through pattern recognition.

[0034] According to a further embodiment, the sensor arrangement can include a processing device, e.g., a control unit or an ASIC, configured to control the operating mode of the first and second micropumps and to read the sensor output signal in the set or adapted operating mode. Thus, the processing device is configured to control the operating mode of a heating element and to read a pressure sensor and / or a temperature sensor coupled to the sensor's sensor chamber.

[0035] According to a further embodiment, the processing device can be configured to (1.) control the operating modes of the first and second micropump to adjust the fluid pressure in the sensor chamber and / or the fluid throughput or flow rate through the sensor chamber, (2.) control the heating element to adjust different or varying temperatures of the fluid and / or the sensor element in the sensor chamber, and (3.) read the sensor output signal at the different temperatures.

[0036] According to a further embodiment, the processing device can also be configured to determine a sensor matrix that includes information (1.) on the read-out sensor output signal, (2.) on the operating mode or the (e.g. different) operating modes of the first and the second micropump, and (3.) on the different temperatures in the sensor chamber.

[0037] According to a further embodiment, the processing device can also be configured to determine the sensor matrix that includes information on the measured pressure in the sensor chamber.

[0038] According to a further embodiment, the processing device can also be configured to determine the sensor matrix, which includes information on the defined fluid flow, e.g. with a defined fluid throughput, through the sensor chamber.

[0039] In summary, the processing device can set different conditions in the sensor chamber, such as one of the different operating modes, the temperature and / or the fluid pressure in the sensor chamber, and can interpret the sensor signal based on the set condition in the sensor chamber. This approach allows for an expansion of the parameter range / parameter space from just the temperature T (with a heating device) to the parameter pressure P (which is adjustable) and also the flow rate Q (generated by the micropumps during the set operating mode, e.g., the purge mode, the vacuum mode, or the overpressure mode).

[0040] The present sensor concept thus opens up numerous possibilities for improving the interpretation of the sensor signal with regard to sensitivity and specificity.

[0041] According to another embodiment, the processing device can be configured to provide adapted actuation with a square wave or sine wave actuation signal for the first and second micropump.

[0042] According to a further embodiment, the processing device can also be configured to determine the presence, quantity or concentration of a target fluid in the fluid in the sensor chamber based on a resulting pressure oscillation profile of the fluid, e.g. with the target fluid, in the sensor chamber.

[0043] Furthermore, the present sensor concept also allows the use of properties of the sensor arrangement to interpret the sensor signal with regard to sensitivity and specificity.

[0044] More precisely, different time constants for pressurizing (and establishing a vacuum) in the sensor chamber can enhance the effect of the specific gas measurement. This can be achieved by pumping slowly or quickly to fill / empty the sensor chamber.

[0045] The same applies to dynamic pressure / vacuum build-up (cyclic pressure changes). Different behavior is expected with varying gas concentrations. However, a modified actuation, e.g., a rectangular actuation, can lead to oscillation of the membranes in the system (including the gas detection membrane), a safety valve membrane, and / or molecules, and can negatively affect or impair the detection process.

[0046] According to one embodiment, the sensor element is sensitive to a chemical or physical condition of the fluid in the fluid chamber. The sensor element can be sensitive to the concentration of a target fluid or target gas in the fluid in the sensor chamber. The sensor element can be sensitive to the presence, quantity, and / or concentration of a target gas in the gas in the sensor chamber, wherein the target gas is VOC (volatile organic compound), CO X e.g. CO or CO2, O X e.g. O2 or O3, or NO XThe sensor element can be a VOC sensor based on a metal oxide, such as MOX, or a metal oxide semiconductor. It can also be an electrochemical sensor with a liquid or solid electrolyte. Furthermore, the sensor element can be sensitive to the concentration of particulate matter in the fluid, such as an ambient gas or ambient air, within the sensor chamber.

[0047] According to a further embodiment, a method for detecting a quantity or concentration of a target fluid in a medium, e.g. a carrier fluid or ambient medium, using the above sensor arrangement, comprises the steps of: adjusting the operating mode of the first and second micropump, e.g. by means of a processing device, and reading the sensor output signal of the sensor in the adjusted operating mode, e.g. by means of the processing device.

[0048] According to one embodiment, the method may further comprise the steps of: adjusting or changing the temperature of the fluid in the sensor chamber and / or the sensor element of the sensor to provide different measurement temperatures in the sensor chamber, e.g. by means of a heating element that is arranged in the sensor chamber or thermally coupled to the sensor chamber; measuring the temperature in the sensor chamber, e.g. by means of a temperature sensor that is located in the sensor chamber or thermally coupled to the sensor chamber; and reading the sensor output signal at the different temperatures, e.g. by means of the processing device.

[0049] According to one embodiment, the method can further comprise the steps of: adjusting the fluid pressure in the sensor chamber and / or the fluid flow rate, e.g., the fluid flow, through the sensor chamber to provide different fluid pressures in the sensor chamber and / or different fluid flow rates, e.g., fluid flows, through the sensor chamber; measuring the fluid pressure in the sensor chamber and / or the fluid flow rate, e.g., the fluid flow, through the sensor chamber, e.g., by means of a pressure sensor that is arranged in the sensor chamber or fluidically coupled to the sensor chamber; and reading the sensor output signal at the different fluid pressures in the sensor chamber and / or the fluid flow rates through the sensor chamber, e.g., by means of the processing device.

[0050] According to one embodiment, the method may further include the step of determining, e.g. by means of the processing device, a sensor output signal matrix which includes information (1.) on the read-out sensor output signal and (2.) on the operating mode, e.g. on different operating modes, of the first and the second micropump.

[0051] According to one embodiment, the method may further include the step of determining the sensor matrix, which includes information (3.) on the different temperatures in the sensor chamber, e.g. by means of the processing device.

[0052] According to one embodiment, the method may further include the step of determining the sensor matrix which includes information (4.) about the measured pressure in the sensor chamber, e.g. by means of the processing device.

[0053] According to one embodiment, the method may further include the step of determining the sensor matrix, which includes information (5.) about the defined fluid flow, e.g. with a defined fluid throughput, through the sensor chamber, e.g. by means of the processing device.

[0054] According to one embodiment, the method may further include the step of determining, e.g. by means of the processing device, the presence, quantity or concentration of a target fluid in the fluid in the sensor chamber based on the resulting sensor output signal matrix, wherein the sensor matrix provides several parameter values, e.g. temperature and / or pressure and / or fluid flow, for each sensor output value. Brief description of the characters

[0055] In the following, exemplary embodiments of the present disclosure are described in more detail with reference to the figures. The figures show: Fig. 1 a schematic cross-sectional view of a sensor arrangement 100 according to an exemplary embodiment; Fig. 2A-E different operating modes of the sensor arrangement 100 according to further embodiments and Fig. 3 a schematic block diagram of a method 300 for detecting a quantity or concentration of a target fluid in a medium with the sensor arrangement according to an embodiment.

[0056] In the following description, exemplary embodiments are explained in more detail with reference to the figures. Elements identical in the figures and the specification, as well as elements with the same functionality and / or the same technical or physical effect, are designated with the same reference numerals or names. The description of these elements and their functionality, as presented in the different exemplary embodiments, is therefore interchangeable or can be applied reciprocally to the different embodiments. Detailed description of the characters

[0057] The following description details exemplary embodiments; however, it should be noted that these embodiments provide many applicable concepts that can be embodied in a wide variety of semiconductor devices. The specific embodiments described are merely illustrative of specific ways of creating and using the present concept and do not limit the scope of the exemplary embodiments. In the following description of exemplary embodiments, identical or similar elements with the same function are assigned the same reference numerals or the same name, and a description of such elements is not repeated for each embodiment. Furthermore, features of the different exemplary embodiments described below can be combined with one another unless expressly stated otherwise.

[0058] When an element is described as "connected" or "coupled" to another element, this means that it may be directly connected or coupled to the other element, or that intermediate elements may exist. Conversely, when an element is described as "directly" connected, "linked," or "coupled" to another element, no intermediate elements exist. Other terms used to describe the relationship between elements are to be understood similarly (e.g., "between" versus "directly between," "adjacent" versus "directly adjacent," and "on" versus "directly on," etc.).

[0059] To facilitate the description of the different embodiments, the figures show a Cartesian coordinate system x, y, z, where the xy-plane corresponds to a first principal surface region of a substrate (= a reference plane = xy-plane), i.e., is parallel to it, where the direction pointing vertically upwards with respect to the reference plane (xy-plane) corresponds to the "+z" direction, and where the direction pointing vertically downwards with respect to the reference plane (xy-plane) corresponds to the "-z" direction. In the following description, the term "lateral" means a direction parallel to the x and / or y direction, i.e., parallel to the xy-plane, while the term "vertical" means a direction parallel to the z-direction. Fig. 1 and Fig. 2A-E is the drawing plane parallel to the xz-plane.

[0060] Fig. Figure 1 shows a schematic cross-sectional view of a sensor arrangement 100 according to an embodiment, while Fig. 2A-E show different operating modes and conditions of the sensor arrangement 100.

[0061] According to one embodiment, the sensor arrangement 100 comprises a first micropump 10, e.g., a microfluidic or peristaltic pump / micropump, which has a normally closed (NC) safety valve 11, e.g., at the micropump outlet 12 of the first micropump 10. The sensor arrangement 100 further comprises a second micropump 20, e.g., a microfluidic or peristaltic pump / micropump, which has a normally closed (NC) safety valve 21, e.g., at the micropump outlet 22 of the second micropump 20. The sensor arrangement 100 further comprises a sensor 30, which has a sensor chamber 31, e.g., a sensor cavity or a sensor volume, with a sensor element 32, e.g., an active sensitive region or layer, in the sensor chamber 31, wherein the sensor 30 is configured to generate a sensor output signal based on a condition, e.g.,to provide a chemical or physical condition of the fluid (= gas or liquid) in the sensor chamber 31.

[0062] As in Fig. As shown in Figure 1, the sensor chamber 31 of the sensor 30 is fluidically coupled between the first and second micropumps 10, 20. The first and second micropumps 10, 20 are configured to provide a defined operating mode of the sensor arrangement 100 based on the respective activation or operating condition of the first and second micropumps 10, 20 for providing (1.) a defined negative fluid pressure in the sensor chamber, (2.) a defined positive fluid pressure in the sensor chamber, or (3.) a defined fluid flow, e.g., a defined fluid throughput, through the sensor chamber.

[0063] According to one embodiment, the first micropump 10 and the second micropump 20 are arranged in a fluidic series connection and have the same fluid pumping direction.

[0064] More precisely, the sensor arrangement 100 comprises two micropumps 10, 20, e.g., two microfluidic or peristaltic pumps, each with a normally closed safety valve 11, 21, wherein the fluid sensor 30, e.g., a gas or liquid sensor, is arranged in a sensor chamber 31, which is fluidically coupled between the two micropumps 10, 20 and is otherwise sealed against the environment E. Since the two micropumps 10, 20 are arranged in a fluidic series connection and have the same fluid pumping direction, both a negative fluid pressure and a positive fluid pressure can be generated in the sealed sensor chamber 31.

[0065] According to one embodiment, the sensor arrangement 100 is configured to detect the presence, quantity, or concentration of a target fluid F T or a target fluid component in the fluid F or medium, e.g., a carrier fluid or ambient medium, in the sensor chamber 31. In this context, the term fluid can refer to a liquid or a gas. If the fluid or medium in the sensor chamber 31 refers to ambient air, the target fluid can refer to a target gas or target gas component present in the ambient air (i.e., the surrounding atmosphere). The present concept is equally applicable to the detection of a target liquid or a target liquid component in the ambient medium. In this context, gases and liquids are collectively referred to as fluids.

[0066] According to one embodiment, the first micropump 10 has a pump inlet 13, a pump chamber 14, and a pump outlet 12, wherein the first micropump 10 is configured to pump the fluid, e.g., ambient air, from the pump inlet 13 through the pump chamber 14 to the pump outlet 12. According to another embodiment, the second micropump 20 has a pump inlet 23, a pump chamber 24, and a pump outlet 22, wherein the second micropump 20 is configured to pump the fluid from the pump inlet 23 through the pump chamber 24 to the pump outlet 22. As shown, the sensor chamber 31 is fluidically coupled between the pump outlet 12 of the first micropump 10 and the pump inlet 23 of the second micropump 20 and is otherwise sealed against the environment, e.g., hermetically sealed or closed.

[0067] As shown in the figures, the pump inlet 13 of the first micropump 10 is fluidically coupled to or forms the fluid inlet 40 of the sensor arrangement 100, and the pump outlet 22 of the second micropump 20 is fluidically coupled to or forms the fluid outlet 40 of the sensor arrangement 100. The first and second micropumps 10, 20 can be configured as microdiaphragm pumps, each comprising a passive check valve as a safety valve 11, 21. The microdiaphragm pumps 20 can include a pump diaphragm 15, 25, wherein a piezoceramic element 16, 26 can be attached to the pump diaphragm 15, 25 such that actuating the piezoceramic element 16, 26 allows the volume of a pump chamber 14, 24 of the diaphragm pumps 10, 20 to be varied. For this purpose, suitable means (e.g.,the device 50 (see below) is provided to apply a voltage to the piezoceramic element 16, 26, which is connected to the pump diaphragm 15, 25, and to remove the same from the in . Fig. to deflect the position shown in 1 into a position in which the volume of the pump chamber 14, 24 is reduced.

[0068] According to one embodiment, the NC safety valve 11 of the first micropump 10 has a valve seat 11-1 and a valve cover 11-2 and is arranged at the pump outlet 12 of the first micropump 10, wherein the NC safety valve 21 of the second micropump 20 also has a valve seat 21-1 and a valve cover 21-2 and is arranged at the pump outlet 22 of the second micropump 20.

[0069] According to one embodiment, the first and second micropumps 10, 20, the sensor 30, and optionally the processing device 50 (see below) can be integrated with a semiconductor substrate, e.g., a silicon substrate. According to one embodiment, the sensor element 32 is sensitive to a chemical or physical condition of the fluid in the fluid chamber 31. The integration of the sensor arrangement 100 (or at least essential sections thereof) in a semiconductor substrate 60 allows for a relatively small dead volume of the micropumps 10, 20 in the range of approximately a few µl (microliters), e.g., in the range between 1 and 10 µl. Based on a relatively small dead volume of the micropumps 10, 20, the measurement time and measurement accuracy of the fluid sensor can be accelerated (increased), and the calibration of this fluid sensor 30 can also be considerably improved.If sharp corners or edges can be (at least partially) avoided in the fluid channels 12-1, 23-1 of the fluid sensor 30, dispersion of the fluid or fluid particles F flowing through the fluid sensor 30 can also be avoided (minimized) or at least reduced.

[0070] The sensor assembly 100 thus has a sealed or enclosed sensor chamber 31. During the measurement, the enclosed sensor chamber 31 provides a defined sensor volume that is sealed off from the surrounding atmosphere outside the gas sensor. This prevents interfering convection when the micropumps 10, 20 are switched off, resulting in favorable conditions for gas measurement.

[0071] Based on this implementation of the sensor arrangement 100, a compact solution for the gas sensor can be achieved, whereby the sensor arrangement 100 can realize either negative or positive pressures in the sensor chamber 31 in a design that is as small and flat as possible and can also be easily integrated into mobile devices.

[0072] The following will show Fig. 2A-E Different operating modes and conditions of the sensor arrangement 100 according to further embodiments. According to one embodiment, the sensor arrangement 100 can be operated in different operating modes.

[0073] Fig. Figure 2A shows the sensor arrangement 100 at standstill or under a non-operating condition (see also Fig. 1).

[0074] Fig. Figure 2B shows the sensor arrangement 100 in a first operating mode, e.g., a vacuum mode. In the first operating mode (vacuum mode) of the sensor arrangement 100, the first micropump 10 is in an off state, e.g., under a switched-off condition or is deactivated, and the second micropump 20 is in an on state, e.g., under a switched-on condition, is activated, or is supplied with energy to provide the defined negative fluid pressure in the sensor chamber 31, as shown in the example in Fig. 2B shown.

[0075] The second micropump can be optimized to provide a high negative pressure relative to atmospheric pressure (ambient pressure). When a high negative pressure is achieved, the sensor assembly can be calibrated very effectively, e.g., in combination with heating the fluid sensor element 32, for example, a gas detection membrane.

[0076] With current technology, the micropumps 10, 20 can, for example, achieve a negative pressure in the range of -40 to -60 kPa (kilopascals). By modifying the design of the micropumps 10, 20, the negative pressure of a single micropump 10, 20 can be increased to approximately -70 to -80 kPa or even -100 kPa. Thus, the first and second micropumps 10, 20 can be optimized to provide a high negative pressure. An optional pressure sensor 33 can, for example, measure the pressure in the sensor chamber 31 as a reference value for sensor readout and as feedback to set a specific pressure, e.g., as a target value, in the sensor chamber 31.

[0077] Fig. Figure 2C shows the sensor arrangement 100 in a second operating mode, e.g., an overpressure mode. In the second operating mode (overpressure mode), the first micropump 10 is in an on state, and the second micropump 20 is in an off state to provide the defined positive fluid pressure in the sensor chamber 31, as shown in the example in Figure 2C. Fig. 2C shown.

[0078] The first micropump 10 can be optimized to provide a high positive pressure; for example, the illustrated micropumps 10 and 20 can currently achieve an air back pressure of up to 100 kPa. An optional pressure sensor 33 can, for example, measure the pressure in the sensor chamber 31 as a reference value for the sensor readout and as feedback to set a specific pressure in the sensor chamber 31. Furthermore, a high or increased pressure in the sensor chamber 31 can influence the binding process of the target fluid F. Tto amplify the signal to the sensor element 32 in the sensor chamber 31. The integration of a pressure sensor 33, e.g. a piezoelectric element, in the sensor chamber 31 allows control of the pressure in the sensor chamber 31 and makes it possible to achieve very accurate measurements.

[0079] Fig. Figure 2D shows the sensor arrangement 100 in an alternative second operating mode. According to a further embodiment, the second operating mode can be a first partial operating mode (as in Fig. 2C) and a subsequent second partial operating mode (as shown in Fig. (shown in 2D) exhibiting, wherein, in the first partial operating mode, the first micropump 10 is in an on-state and the second micropump 20 is in an off-state to provide the defined positive fluid pressure in the sensor chamber 31. In the (immediately) subsequent second partial operating mode, the Fig. In 2D, the first micropump 10 is in an off state (switched to such a state), and the second micropump 20 is in the off state (held) to provide a defined amount of fluid, i.e., a defined fluid volume or defined measurement volume, in the sensor chamber 31, e.g., within the fluid path and the sensor chamber. Thus, the sensor element 32 can interact with a defined amount of the "charged" fluid F that is introduced into the sensor chamber 31.

[0080] Fig. Figure 2E shows the sensor arrangement 100 in a third operating mode, e.g., a flushing mode. In the third operating mode (flushing mode), the first micropump 10 and the second micropump 20 are both on to provide the defined fluid flow, e.g., with a defined fluid throughput, through the sensor chamber 31, as shown in the example in Figure 2E. Fig. 2E shown.

[0081] The flushing mode of the sensor arrangement, for example in combination with heating the fluid sensor element, can provide or even enhance effective calibration.

[0082] According to one embodiment, an energy-efficient flushing mode could be implemented by actuating the micropumps 10, 20 under a phase shift of 180°, which leads to an improved flow rate of the fluid through the sensor chamber 31.

[0083] According to one embodiment, the sensor arrangement 100 can further comprise a pressure sensor 33, which is arranged in the sensor chamber 31 or is fluidically coupled to the sensor chamber 31, for measuring a fluid pressure in the sensor chamber 31.

[0084] If the pressure at the sensor element 32, e.g., the gas sensor layer, is adjustable, this feature can generally be used to obtain more specific sensor feedback. More precisely, gas measurement at certain pressure levels leads to gas molecule-specific binding to the sensor element 32, thus enabling specific gas measurement. The provision of the pressure sensor 33 therefore allows the pressure at the sensor element 32 (the gas sensor membrane) to be changed, so that a pressure-dependent fluid (gas) absorption profile can be detected.

[0085] According to one embodiment, the first micropump 10 can have several micropump elements in a cascaded arrangement, e.g. fluidically connected in series to provide an increased positive fluid pressure in the sensor chamber, and / or fluidically connected in parallel to provide an increased fluid flow rate through the sensor chamber 31.

[0086] According to one embodiment, the second micropump 20 can have several micropump elements in a cascaded arrangement, e.g. fluidically connected in series to provide an increased negative fluid pressure in the sensor chamber, and / or fluidically connected in parallel to provide an increased fluid flow rate through the sensor chamber 31.

[0087] Cascading pumps 10 and 20 can therefore increase the negative or positive pressure. However, cascading pumps 10 and 20 may require a modified cover for the pumps 10 and 20.

[0088] According to one embodiment, the sensor arrangement 100 can further comprise a heating element 34, which is arranged in the sensor chamber 31 or thermally coupled to the sensor chamber 31, for heating the fluid or adjusting the temperature of the fluid in the sensor chamber 31 and / or for heating the sensor element 32 of the sensor 30. Thus, the heating element 34 can provide different measurement temperatures in the sensor chamber 31. Furthermore, the heating element 34 can provide or at least support a "reset" (a regeneration or restoration) of the sensor element 32, e.g., the active sensor region.

[0089] According to one embodiment, the sensor arrangement 100 can further comprise a temperature sensor 35, which is arranged in the sensor chamber 31 or is thermally coupled to the sensor chamber 31, for measuring the temperature in the sensor chamber 31.

[0090] As stated above, a pressure-dependent fluid (gas) absorption profile can be detected, whereby the provision of the temperature sensor 35 and / or the heating device 34 can ensure temperature control of the fluid F in the sensor chamber 31. Based on a controlled temperature and a controlled pressure in the sensor chamber 31, a temperature / pressure matrix measurement enables the detection of specific molecules from this matrix, e.g., by pattern recognition.

[0091] Thus, the present sensor arrangement 100 can combine the technical effects of adjusting and controlling the pressure and temperature of the fluid and / or the sensor element 32 and the sensor chamber 31 of the sensor 30.

[0092] More precisely, the sensor output signal S can be interpreted using... OUTDifferent conditions, e.g. temperature and / or pressure conditions, may be set in the sensor chamber 31, e.g. if the pressure sensor 33, the heating device 34 and optionally also the temperature sensor 35 are implemented in the sensor chamber 31.

[0093] If the sensor assembly 100 is implemented as a VOC gas sensor (VOC = volatile organic compound), it is difficult to identify specific fluids or fluid compounds, e.g., gases or gas components, from among the multiple organic compounds. This is especially true if the sensor assembly 100 is intended to measure toxic and / or hazardous gases such as formaldehyde or benzene.

[0094] Based on the sensor concept according to the invention, it is possible to measure the sensor output signal S OUTto be interpreted under different operating conditions, which are adjustable in the sensor chamber 31, so that the present concept allows an extension of the parameter space (the parameter boundary) from only the temperature T (with the heating device 34) to the parameter “pressure p” adjustable by the processing device 50 and also to the flow rate Q, which can be generated by the micropumps 10, 20 during the purging mode (see for example Fig. 2E).

[0095] The following describes some example implementations of the parameter space for interpreting the sensor output signal: - Linear field: o Variation of the pressure between p1... p2 at a given temperature T. - Matrix (PxT): The pressure can be varied between p1... p2, and the temperature can be varied between T1,... T2. The sensor feedback of the entire matrix can be used to detect a specific gas, thus improving the specificity of the gas sensor 30. - Matrix (QxT): ◯ Variation of the flow rate between Q1,...Q2, variation of the temperature between T1,...T2, the sensor feedback of the entire matrix can be used to detect a specific gas, so that the specificity of the fluid sensor 30 can be improved.

[0096] According to the examples given, the interpretation of this measurement matrix can be supported by machine learning and AI algorithms (AI = artificial intelligence).

[0097] According to one embodiment, the sensor arrangement 100 can include a processing device 50, e.g. a control unit or ASIC, which is configured to control the operating mode of the first micropump 10 with a first control signal S 10 to control the operating mode of the second micropump 20 with a second control signal S 20 to control and the sensor output signal S OUT to read the sensor 30 in the set operating mode. Thus, the processing device 50 is designed to control the operating mode of a heating element 34 and to read a pressure sensor 33 and / or a temperature sensor 35, which is coupled to the sensor chamber 31 of the sensor 30.

[0098] According to one embodiment, the processing device 50 is configured to (1) control the operating modes of the first and second micropump 10, 20 to adjust the fluid pressure in the sensor chamber 31 and / or the fluid throughput or fluid flow through the sensor chamber 31, (2) control the heating element 34 to adjust different or varying temperatures of the fluid and / or the sensor element in the sensor chamber 31, and (3) read out the sensor output signal at the different temperatures.

[0099] According to one embodiment, the processing device 50 can be configured to determine a sensor matrix that includes information (1) on the read-out sensor output signal, (2) on the operating mode, e.g. on different operating modes, of the first and the second micropump 10, 20 and (3) on the different temperatures in the sensor chamber 31.

[0100] According to one embodiment, the processing device 50 can further be configured to determine the sensor matrix which includes information (4) about the measured pressure in the sensor chamber 31.

[0101] According to one embodiment, the processing device 50 can further be configured to determine the sensor matrix which includes information (5) about the defined fluid flow, e.g. with a defined fluid throughput, through the sensor chamber 31.

[0102] In summary, the processing device can set different conditions in the sensor chamber, such as one of the different operating modes, the temperature and / or the fluid pressure in the sensor chamber, and can interpret the sensor signal based on the set condition in the sensor chamber. This approach allows for an expansion of the parameter range / parameter space from just the temperature T (with a heating device) to the parameter pressure P (which is adjustable) and also the flow rate Q (generated by the micropumps during the set operating mode, e.g., the purge mode, the vacuum mode, or the overpressure mode).

[0103] The present sensor concept thus opens up numerous possibilities for improving the interpretation of the sensor signal with regard to sensitivity and specificity.

[0104] According to one embodiment, the processing device 50 can further be configured to provide adapted actuation with a square wave or sine wave actuation signal S 10 , S 10 to provide 10, 20 for the first and second micropump.

[0105] According to one embodiment, the processing device 50 can further be configured to determine the presence, quantity or concentration of a target fluid in the fluid in the sensor chamber 31 based on a resulting pressure oscillation profile of the fluid, e.g. with the target fluid, in the sensor chamber 31.

[0106] Furthermore, the present sensor concept also allows the use of dynamic properties of the sensor arrangement to interpret the sensor signal with regard to sensitivity and specificity.

[0107] More precisely, different time constants for pressurizing (and building up the vacuum) in the sensor chamber can enhance the effect of the specific gas measurement. This can be achieved by pumping slowly or quickly to fill / empty the sensor chamber.

[0108] The same applies to dynamic pressure / vacuum build-up (cyclic pressure changes). Different behavior is expected with varying gas concentrations. However, a modified actuation, e.g., a rectangular actuation, can lead to oscillation of the membranes in the system (including the gas detection membrane), a safety valve membrane, and / or molecules, and can negatively affect or impair the detection process.

[0109] According to one embodiment, the processing device 50 can further be configured to provide an adapted or set actuation with a square wave or sine wave actuation signal S10 , S 20 to provide 10, 20 each for the first and / or second micropump.

[0110] According to one embodiment, the processing device 50 can be configured to provide rectangular actuation (only) when a high volume flow rate Q is required to "clean" the sensor 30. The processing device 50 can then be configured to switch to harmonic actuation, e.g., sinusoidal actuation, for unicast equalization, or can be configured to stop the pump operation during a detection operation.

[0111] According to one embodiment, the processing device 50 can be configured to acquire or read out a "pressure oscillation profile" of the fluid or gas F, wherein the pressure oscillation profile is specific for some fluid or gas molecules. This can lead to different binding behavior of the target fluid and thus to a variation in the sensor response (sensor output signal), which can be interpreted by the processing device 50 to determine the type, quantity, and / or concentration of the target fluid F. T in sensor chamber 31. In addition, a very specific fluid or gas sensitivity of the sensor 30 can be provided using Al analysis (Al = artificial intelligence) and pattern recognition.

[0112] According to the present fluid capture concept, dynamic influences on the process of chemical bonding of the target fluid F can be TThe sensor element 32, e.g., the sensor membrane, is observed and interpreted. However, it should be noted that dynamic influences may be difficult to control, as external influences such as temperature changes, pressure changes, etc., can easily cause the dynamics to exceed their operating range.

[0113] According to one embodiment, the sensor element 32 is designed to measure the concentration of a target fluid F. T or target gas in the fluid F in the sensor chamber 31. According to one embodiment, the sensor element 32 is sensitive to the presence, quantity and / or concentration of a target gas in the gas in the sensor chamber 31, wherein the target gas is VOC (VOC = volatile organic compound), CO X (e.g. CO or CO2), O X (e.g. O2 or O3) or NO X (e.g., NO or NO2) is present.

[0114] According to one embodiment, the sensor element 32 is a VOC sensor based on a metal oxide, e.g., a MOX or metal oxide semiconductor. A VOC gas can include formaldehyde (CH₂O), benzene, hydrogen sulfide (H₂S), MTBE, methylene chloride, perchloroethylene, chlorofluorocarbons and carbon chlorides, tetrachloroethene, etc. However, this list of detectable VOC gases is not exhaustive.

[0115] According to one embodiment, the sensor element 32 is an electrochemical sensor with a liquid or solid electrolyte material. According to another embodiment, the sensor element 32 is sensitive to a concentration of particle matter in the fluid, e.g., an ambient gas or ambient air, in the sensor chamber 31.

[0116] According to one embodiment, the safety valve 11, 21 and the valve covers 11-2, 21-2, and optionally the valve seats 11-11, 21-1, can be integrated in silicon to provide silicon micropumps 10, 20, or can be formed with metal to provide metal micropumps 10, 20. Alternatively, the valve covers 11-2, 21-2 can be attached as polymer diaphragms and clamped between the respective micropump 10, 20 and the support (substrate) 60.

[0117] According to one embodiment, the safety valves 11, 21 are integrated with the respective micropumps 10, 20, wherein the micropumps 10, 20 can be bonded to the carrier 60 and / or manifold 60'. In the case of a bonding process, low degassing is recommended to maintain the operating characteristics of the micropumps 10, 20.

[0118] In the case of the implementation of a polymer safety valve diaphragm 11-2, 21-2, the micropumps 10, 20 can be clamped to the manifold. Low-degassing processing is also recommended for the polymer material in this case.

[0119] A distributor 60' of the sensor arrangement 100 and / or the sensor 30, and in particular the fluid channels and the sensor chamber 31 of the sensor 30, could be realized by means of metal foils which can be joined together by a laser welding process.

[0120] According to another embodiment, the distributor 60' of the sensor assembly 100 could be directly integrated into a PCB (printed circuit board), using appropriate techniques for creating buried vias to construct the respective channels and chambers within the PCB. In the case of a PCB implementation, the only materials in contact with the test fluid are the semiconductor material, e.g., silicon, and the PCB material, e.g., FR4. If necessary, the PCB material can be coated with a metal, e.g., gold, to prevent particle accumulation. This approach enables the use of MEMS technology (microelectromechanical system) and manufacturing processes in combination with MEMS sensors.The metal-coated surfaces of the 60' manifold provide low degassing during the manufacture and use of the sensor.

[0121] According to another embodiment, the distributor 60' can be made of a glass material, which also achieves a low fluid (e.g. gas) particle accumulation.

[0122] As described above, a pressure sensor 33 can be arranged in or integrated into the sensor chamber 31, or it can be fluidically coupled to the sensor chamber 31 to measure a fluid pressure in the sensor chamber 31. Providing a controlled pressure P in the sensor chamber 31 enables very accurate measurements, whereby a pressure sensor 33 can be implemented by means of a piezoresistive pressure sensor, a capacitive pressure sensor, a piezoelectric element, etc.

[0123] Furthermore, a temperature sensor 35 can also be integrated into a number of (currently available) pressure sensors 33, which can be used to measure and control the temperature in the sensor chamber 31 based on the heating operation of the heating element 34. The heating element 34 can be integrated into the sensor chamber 31 or can be thermally coupled to the sensor chamber 31 in order to heat the fluid F in the sensor chamber 31 and / or in the sensor element 32 of the sensor 30.

[0124] The following section describes some general integration steps for manufacturing the sensor assembly as an example.

[0125] As a first step, both micropumps 10, 20 can be formed from or within the same wafer and separated in a single piece. In step 2, the flow channels 12-1, 23-1 and the gas sensor chamber 31 can be integrated into the chip, for example, by etching, together with the two micropumps 10, 20. Based on semiconductor processing steps, dead volumes of the sensor 30 of less than 1 µl or less than 10 µl can be achieved. In a third step, the fluid sensor technology (e.g., the gas sensor) is integrated into the silicon chip / silicon substrate 60, achieving dead volumes of less than 0.5 µl.

[0126] According to one embodiment, a microprocessor ASIC (ASIC = application specific integrated circuit) can be combined with a sensor ASIC for only one chip (separate or isolated semiconductor substrate), which allows direct integration into the distributor 60' with the lowest possible energy consumption.

[0127] According to one embodiment, the sensor element 32 in the sensor chamber 31 could also be sensitive to a concentration of particle matter in the fluid F. In this context, it should be noted that a fluid sensor or gas sensor 30 could exhibit cross-contamination by particles, which could be detected by a correspondingly equipped sensor for detecting particle matter.

[0128] Adsorption, i.e., the adhesion of atoms, ions, or molecules from a fluid (a gas, a liquid, or a dissolved solid) to a surface such as the surface of sensor element 32, could enhance the chemical reaction, and therefore the resulting output signal S OUT The sensor element 32 in an overpressure mode in the sensor chamber is suitable for detecting the target fluid, i.e., the presence and / or concentration of the target fluid F. T to record.

[0129] According to one embodiment, the sensor arrangement could also be used to implement a micropump desiccator or desiccator. A desiccator is a seed container containing a desiccant, used to preserve moisture-sensitive items for another purpose. A common use for desiccators is to protect chemicals that are hygroscopic or that react with water from the ambient humidity.

[0130] According to a further embodiment, the sensor arrangement, which has at least two micropumps 10, 20, can also support and / or provide suitable restoration (a reset or regeneration) of the sensor element, e.g., the active sensor region, by means of the flushing mode, as described above.

[0131] Fig.Figure 3 shows a schematic block diagram of a method 200 for detecting a quantity or concentration of a target fluid in a medium with the sensor arrangement according to an embodiment.

[0132] According to one embodiment, the method 300 for detecting a quantity or concentration of a target fluid in a medium, e.g. a carrier fluid or ambient medium, with the sensor arrangement 100, as described above, comprises the steps of: adjusting the operating mode of the first and second micropump 10, 20, e.g. by means of the processing device 50, and reading the sensor output signal of the sensor 30 in the adjusted operating mode, e.g. by means of the processing device 50.

[0133] According to one embodiment, the method 300 may further comprise the steps: adjusting or changing (setting) 330 the temperature of the fluid in the sensor chamber and / or the sensor element 32 of the sensor 30 to provide different measurement temperatures in the sensor chamber 31, e.g. by means of a heating element 34 which is arranged in the sensor chamber or thermally coupled to the sensor chamber, measuring 340 the temperature in the sensor chamber 31, e.g. by means of a temperature sensor 35 which is located in the sensor chamber or thermally coupled to the sensor chamber 31, and reading 350 the sensor output signal at the different temperatures, e.g. by means of the processing device 50.

[0134] According to one embodiment, the method 300 can further comprise the steps: adjusting 360 the fluid pressure in the sensor chamber 31 and / or the fluid flow rate, e.g., the fluid flow, through the sensor chamber 31, to provide different fluid pressures in the sensor chamber 31 and / or different fluid flow rates, e.g., fluid flows, through the sensor chamber 31; measuring 370 the fluid pressure in the sensor chamber and / or the fluid flow rate, e.g., the fluid flow, through the sensor chamber 31, e.g., by means of a pressure sensor 33 that is arranged in the sensor chamber or fluidically coupled to the sensor chamber 31; and reading 380 the sensor output signal at the different fluid pressures in the sensor chamber 31 and / or the fluid flow rates through the sensor chamber 31, e.g., by means of the processing device 50.

[0135] According to one embodiment, the method 300 may further include the step: Determining 390, e.g. by means of the processing device 50, a sensor output signal matrix which includes information (1) about the read-out sensor output signal and (2) about the operating mode, e.g. about different operating modes, of the first and the second micropump 10, 20.

[0136] According to one embodiment, the method 300 may further include the step: Determining 400 of the sensor matrix, which includes information (3) about the different temperatures in the sensor chamber 31, e.g. by means of the processing device 50.

[0137] According to one embodiment, the method 300 may further include the step: Determining 410 of the sensor matrix which includes information (4) about the measured pressure in the sensor chamber 31, e.g. by means of the processing device 50.

[0138] According to one embodiment, the method 300 may further include the step: Determining 430 of the sensor matrix, which includes information (5) about the defined fluid flow, e.g. with a defined fluid throughput, through the sensor chamber 31, e.g. by means of the processing device 50.

[0139] According to one embodiment, the method 300 may further include the step: Determining 430, e.g. by means of the processing device, the presence, quantity or concentration of a target fluid in the fluid in the sensor chamber 31 on the basis of the resulting sensor output signal matrix, wherein the sensor matrix provides several parameter values, e.g. temperature and / or pressure and / or fluid flow, for each sensor output value.

[0140] In the case of using the present sensor arrangement 100 as a VOC sensor, it is possible to resolve different VOCs and their concentrations in the fluid or medium (e.g., carrier gas) in the sensor chamber 31, since the specific sensor output signal matrix provides several parameter values, e.g., temperature and / or pressure and / or fluid flow, for each sensor output value. Thus, based on the sensor output signal matrix and the multiple parameter values ​​for each sensor output value, such as temperature and / or pressure and / or fluid flow, different VOCs and their concentrations can be determined by evaluating the distribution of the different parameter values ​​and sensor output values ​​and / or by the characteristic assignment of the sensor output values ​​to the different parameter values. A characteristic sensor signal measurement field for the different VOCs can therefore be established based on the sensor output signals with the assigned measurement parameter (e.g., temperature, pressure, and / or fluid flow).Temperature and / or pressure and / or fluid flow in the fluid chamber) are derived.

[0141] According to a further embodiment, the micropumps 10, 20 can be manufactured such that they have a very low dead volume, allowing the measurement volume in the sensor chamber 31 between the two micropumps 10, 20 to be precisely determined. Thus, the present sensor arrangement 100 can be implemented with a sensor element 32 that consumes or absorbs the target gas. Based on this gas detection concept, the micropumps 10, 20 can deliver a defined fluid volume to the sensor chamber 31, whereby the target gas, e.g., all target gas molecules, can be consumed, absorbed, or bound to the sensor element 32. Based on the defined measurement volume and the resulting sensor output signal, e.g., triggered by all or substantially all target gas molecules in the sensor chamber 31, the exact target gas concentration in the sensor chamber 31, which has a defined measurement volume, can be determined.

[0142] Further examples and aspects are described, which can be used alone or in combination with the features and functionalities described here.

[0143] According to one embodiment, a sensor arrangement 100 comprises a first micropump 10 having a normally closed (NC) safety valve 11, a second micropump 20 having a normally closed (NC) safety valve 21, and a sensor 30 having a sensor chamber 31 with a sensor element 32 in the sensor chamber 31, wherein the sensor 30 is configured to output a sensor output signal S OUTbased on a condition of the fluid F in the sensor chamber 31, wherein the sensor chamber 31 of the sensor 30 is fluidically coupled between the first and the second micropump 10, 20 and wherein the first and the second micropump 10, 20 are configured to provide a defined operating mode of the sensor arrangement 100 based on the respective activation condition of the first and the second micropump 10, 20 for providing (1.) a defined negative fluid pressure in the sensor chamber 31, (2.) a defined positive fluid pressure in the sensor chamber 31 or (3.) a defined fluid flow through the sensor chamber 31.

[0144] According to one embodiment, the first micropump 10 and the second micropump 20 are arranged in a fluidic series connection and have the same fluid pumping direction.

[0145] According to one embodiment, in a first operating mode the first micropump 10 is in an off state, and the second micropump 20 is in an on state to provide the defined negative fluid pressure in the sensor chamber 31, wherein in a second operating mode the first micropump 10 is in an on state and the second micropump 20 is in an off state to provide the defined positive fluid pressure in the sensor chamber 31, and / or wherein in a third operating mode the first micropump 10 is in an on state and the second micropump 20 is in an on state to provide the defined fluid flow through the sensor chamber 31.

[0146] According to one embodiment, the second operating mode has a first partial operating mode and a subsequent second partial operating mode, wherein, in the first partial operating mode, the first micropump 10 is in an on-state and the second micropump 20 is in an off-state to provide the defined positive fluid pressure in the sensor chamber 31, and wherein, in the subsequent second partial operating mode, the first micropump 10 is in an off-state and the second micropump 20 is in the off-state to provide a defined amount of fluid in the sensor chamber 31.

[0147] According to one embodiment, the first micropump 10 has a pump inlet 13, a pump chamber 14 and a pump outlet 12, wherein the first micropump 10 is configured to pump the fluid F from the pump inlet 13 through the pump chamber 31 to the pump outlet 12, wherein the second micropump 20 has a pump inlet 23, a pump chamber 24 and a pump outlet 22, wherein the second micropump 20 is configured to pump the fluid F from the pump inlet 23 through the pump chamber 24 to the pump outlet 22, and wherein the sensor chamber 31 is fluidically coupled between the pump outlet 12 of the first micropump 10 and the pump inlet 23 of the second micropump 20 and is otherwise sealed against the environment E.

[0148] According to one embodiment, the NC safety valve 11 of the first micropump 10 has a valve seat 11-1 and a valve cover 11-2 and is arranged at the pump outlet 12 of the first micropump 10, and the NC safety valve 21 of the second micropump 20 has a valve seat 21-1 and a valve cover 21-2 and is arranged at the pump outlet 22 of the second micropump 20.

[0149] According to one embodiment, the sensor arrangement 100 further comprises a pressure sensor 33 in the sensor chamber 31, or fluidically coupled to the sensor chamber 31, for measuring a fluid pressure in the sensor chamber 31.

[0150] According to one embodiment, the sensor arrangement 100 further comprises a heating element 34 in the sensor chamber 31, or thermally coupled to the sensor chamber 31, for heating the fluid F in the sensor chamber 31 and / or the sensor element 32 of the sensor 30.

[0151] According to one embodiment, the sensor arrangement 100 further comprises a temperature sensor 35 in the sensor chamber 31, or thermally coupled to the sensor chamber 31, for measuring the temperature in the sensor chamber 31.

[0152] According to one embodiment, the sensor arrangement 100 further comprises a processing device 50 which is configured to control the operating mode of the first and the second micropump 10, 20 and to process the sensor output signal S OUT to read the sensor 30 in the adapted operating mode.

[0153] According to one embodiment, the processing device 50 is designed to control the operating mode of a heating element 34 and to read a pressure sensor 33 and / or a temperature sensor 35 which is coupled to the sensor chamber 31 of the sensor.

[0154] According to one embodiment, the first micropump 10 has several micropump elements in a cascaded arrangement, and / or the second micropump 20 has several micropump elements in a cascaded arrangement.

[0155] According to one embodiment, the processing device 50 is configured to (1.) control the operating modes of the first and second micropump 10, 20 to adjust the fluid pressure in the sensor chamber 31 and / or the fluid flow rate through the sensor chamber 31, (2.) control the heating element 34 to adjust different temperatures in the sensor chamber 31, and (3.) read out the sensor output signal at the different temperatures.

[0156] According to one embodiment, the processing device 50 is configured to determine a sensor matrix that provides information (1.) about the read-out sensor output signal S OUT, (2.) to the operating mode of the first and second micropump 10, 20 and (3.) to the different temperatures in the sensor chamber 31.

[0157] According to one embodiment, the processing device 50 is further configured to determine the sensor matrix which includes information (4.) about the measured pressure in the sensor chamber 31.

[0158] According to one embodiment, the processing device 50 is further configured to determine the sensor matrix which includes information (5.) about the defined fluid flow through the sensor chamber 31.

[0159] According to one embodiment, the processing device 50 is designed to provide a customized actuation with a square wave or sine wave actuation signal S 10 , S 20 to provide for the first and second micropump.

[0160] According to one embodiment, the processing device 50 is further configured to detect the presence, quantity, or concentration of a target fluid F T to determine the fluid in the sensor chamber 31 based on a resulting pressure oscillation profile of the fluid F in the sensor chamber 31.

[0161] According to one embodiment, the first and second micropump 10, 20, the sensor 30 and the processing device 50 are integrated with a semiconductor substrate.

[0162] According to one embodiment, the sensor element 32 is sensitive to a chemical or physical condition of the fluid F in the sensor chamber 31.

[0163] According to one embodiment, the sensor element 32 is designed to measure the concentration of a target fluid F. T sensitive in the fluid in sensor chamber 31.

[0164] According to one embodiment, the sensor element 32 is for the presence, quantity and / or concentration of a target gas F T sensitive to the gas in sensor chamber 31, where the target gas is a volatile organic compound (VOC), CO X , O X or NO X exhibits.

[0165] According to one embodiment, the sensor element 32 is a VOC sensor based on metal oxide.

[0166] According to one embodiment, the sensor element 32 is an electrochemical sensor with a liquid or solid electrolyte material.

[0167] According to one embodiment, the sensor element 32 is sensitive to a concentration of particle matter in the fluid F in the sensor chamber 31.

[0168] According to one embodiment, a method 300 for detecting a quantity or concentration of a target fluid F TIn a medium F with the above sensor arrangement 100, the steps are: adjusting 310 the operating mode of the first and second micropump 10, 20 and reading 320 the sensor output signal S OUT of sensor 30 in the set operating mode.

[0169] According to one embodiment, the method further comprises the step of: setting 330 the temperature of the fluid F in the sensor chamber 31 and / or of the sensor element 32 of the sensor 30 to provide different measurement temperatures in the sensor chamber 31; measuring 340 the temperature in the sensor chamber 31 and reading 350 the sensor output signal S OUT at the different temperatures.

[0170] According to one embodiment, the method 300 further comprises the steps of: adjusting 360 the fluid pressure in the sensor chamber 31 and / or the fluid flow rate through the sensor chamber 31 to provide different fluid pressures in the sensor chamber 31 and / or different fluid flow rates through the sensor chamber 31, measuring 370 the fluid pressure in the sensor chamber 31 and / or the fluid flow rate through the sensor chamber 31, and reading 380 the sensor output signal S OUT with the different fluid pressures in the sensor chamber 31 and / or the fluid flow rates through the sensor chamber 31.

[0171] According to one embodiment, the method 300 further comprises the step: Determining 390 a sensor output signal matrix which includes information (1.) about the read-out sensor output signal and (2.) about the set operating mode of the first and the second micropump 10, 20.

[0172] According to one embodiment, the method 300 further comprises the step: Determining 400 of the sensor matrix, which includes information (3.) about the different temperatures in the sensor chamber 31.

[0173] According to one embodiment, the method 300 further comprises the step: Determining 410 of the sensor matrix, which includes information (4.) about the measured pressure in the sensor chamber 31.

[0174] According to one embodiment, the method 300 further comprises the step: Determining 420 of the sensor matrix, which includes information (5.) about the defined fluid flow through the sensor chamber 31.

[0175] According to one embodiment, the method further comprises the step: Determining 430 the presence, quantity or concentration of a target fluid F T in the fluid F in the sensor chamber 31 based on the resulting sensor output signal matrix.

[0176] Although some aspects were described as features related to a device, it is clear that such a description can also be seen as a description of corresponding features of a process. Although some aspects were described as features related to a process, it is clear that such a description can also be seen as a description of corresponding features relating to the functionality of a device.

[0177] Depending on specific implementation requirements, embodiments of the processing device 50 can be implemented by hardware or by software, or at least partially by hardware or at least partially by software. The implementation can be carried out using a digital storage medium, such as a floppy disk, DVD, Blu-ray disc, CD, ROM, PROM, EPROM, EEPROM, or FLASH memory, on which electronically readable control signals are stored. These signals interact (or can interact) with a programmable computer system in such a way as to execute the respective process. Therefore, the digital storage medium can be computer-readable.Some embodiments include a data carrier containing electronically readable control signals capable of interacting with a programmable computer system to perform one of the methods described herein.

[0178] In general, embodiments of the processing device can be implemented as a computer program product with program code, wherein the program code is effective in carrying out one of the methods when the computer program product is executed on a computer. The program code can, for example, also be stored on a machine-readable medium. Other embodiments include the computer program for carrying out one of the methods described herein being stored on a machine-readable medium. In other words, an embodiment of the method is thus a computer program with program code for carrying out one of the methods described herein when the computer program is executed on a computer.

[0179] Another embodiment of the methods is a data carrier (or a digital storage medium or a computer-readable medium) on which the computer program for performing one of the methods described herein is recorded. The data carrier, digital storage medium, or recording medium is typically tangible and / or non-volatile. Another embodiment comprises a processing device, for example, a computer or a programmable logic device, configured or adapted to perform one of the methods described herein. Another embodiment comprises a computer on which the computer program for performing one of the methods described herein is installed.

[0180] In some embodiments, a programmable logic device (for example, a field-programmable gate array) can be used to perform some or all of the functionalities of the methods described herein. In some embodiments, a field-programmable gate array can interact with a microprocessor to perform one of the methods described herein. Generally, the methods are preferably performed by any hardware device.

[0181] The device described herein can be implemented using a hardware device, a computer, or a combination of both. The methods described herein can be performed using a hardware device, a computer, or a combination of both.

[0182] The preceding detailed description shows that various features are grouped into examples to make the disclosure more concise. This method of disclosure should not be interpreted as reflecting an intention that the claimed examples require more features than are expressly mentioned in each claim. Rather, as reflected in the following claims, the subject matter may consist of fewer than all the features of a single disclosed example. Thus, the following claims are hereby incorporated into the detailed description, with each claim being able to stand alone as a separate example.While each claim can stand alone as a separate example, it should be noted that although a dependent claim may refer to a specific combination with one or more other claims, other examples may also include a combination of the dependent claim with the subject matter of any other dependent claim, or a combination of any feature with other dependent or independent claims. Such combinations are proposed herein unless it is stated that a specific combination is not intended. Furthermore, it is intended to include features of a claim in any other independent claim, even if that claim is not directly dependent on the independent claim.

[0183] Although specific embodiments are presented and described herein, it will be understood by the person skilled in the art that the specific embodiments shown and described can be replaced by numerous alternative and / or equivalent implementations without departing from the scope of the present embodiments. It is intended that this application covers all adaptations or variants of the specific embodiments explained herein. Therefore, it is intended that the embodiments are limited only by the claims and their equivalents.

Claims

[1] Sensor arrangement (100) comprising: a first micropump (10) which has a normally closed (NC) safety valve (11), a second micropump (20) which has a normally closed (NC) safety valve (21), wherein the first micropump (10) and the second micropump (20) are arranged in a fluidic series connection and have the same fluid pumping direction, and a sensor (30) having a sensor chamber (31) with a sensor element (32) in the sensor chamber (31), wherein the sensor (30) is configured to provide a sensor output signal (S) OUT ) based on a condition of a fluid (F) in the sensor chamber (31), wherein the sensor chamber (31) of the sensor (30) is fluidically coupled between the first and the second micropump (10, 20) and wherein the first and second micropump (10, 20) are configured to provide a defined operating mode of the sensor arrangement (100) based on the respective activation condition of the first and second micropump (10, 20) to provide (1.) a defined negative fluid pressure in the sensor chamber (31), (2.) a defined positive fluid pressure in the sensor chamber (31) or (3.) a defined fluid flow through the sensor chamber (31). [2] Sensor arrangement (100) according to claim 1, wherein in a first operating mode the first micropump (10) is in an off state and the second micropump (20) is in an on state to provide the defined negative fluid pressure in the sensor chamber (31), wherein in a second operating mode the first micropump (10) is in an on state and the second micropump (20) is in an off state to provide the defined positive fluid pressure in the sensor chamber (31), and / or wherein in a third operating mode the first micropump (10) is in an on state and the second micropump (20) is in an on state to provide the defined fluid flow through the sensor chamber (31). [3] Sensor arrangement (100) according to claim 2, wherein the second operating mode comprises a first partial operating mode and a subsequent second partial operating mode, wherein, in the first partial operating mode, the first micropump (10) is in an on-state and the second micropump (20) is in an off-state to provide the defined positive fluid pressure in the sensor chamber (31), and wherein, in the subsequent second partial operating mode, the first micropump (10) is in an off-state and the second micropump (20) is in the off-state to provide a defined amount of fluid in the sensor chamber (31). [4] Sensor arrangement (100) according to one of the preceding claims, wherein the first micropump (10) has a pump inlet (13), a pump chamber (14) and a pump outlet (12), wherein the first micropump (10) is configured to pump the fluid (F) from the pump inlet (13) through the pump chamber (31) to the pump outlet (12), wherein the second micropump (20) has a pump inlet (23), a pump chamber (24) and a pump outlet (22), wherein the second micropump (20) is configured to pump the fluid (F) from the pump inlet (23) through the pump chamber (24) to the pump outlet (22), and wherein the sensor chamber (31) is fluidically coupled between the pump outlet (12) of the first micropump (10) and the pump inlet (23) of the second micropump (20) and is otherwise sealed against the environment (E). [5] Sensor arrangement (100) according to one of the preceding claims, wherein the NC safety valve (11) of the first micropump (10) has a valve seat (11-1) and a valve cover (11-2) and is arranged at the pump outlet (12) of the first micropump (10), and wherein the NC safety valve (21) of the second micropump (20) has a valve seat (21-1) and a valve cover (21-2) and is arranged at the pump outlet (22) of the second micropump (20). [6] Sensor arrangement (100) according to one of the preceding claims, further comprising: a pressure sensor (33) in the sensor chamber (31), or fluidically coupled to the sensor chamber (31), for measuring a fluid pressure in the sensor chamber (31). [7] Sensor arrangement (100) according to one of the preceding claims, further comprising: a heating element (34) in the sensor chamber (31), or thermally coupled to the sensor chamber (31), for heating the fluid (F) in the sensor chamber (31) and / or the sensor element (32) of the sensor (30). [8] Sensor arrangement (100) according to one of the preceding claims, further comprising: a temperature sensor (35) in the sensor chamber (31), or thermally coupled to the sensor chamber (31), for measuring the temperature in the sensor chamber (31). [9] Sensor arrangement (100) according to one of the preceding claims, further comprising: a processing device (50) configured to control the operating mode of the first and second micropump (10, 20) and to read the sensor output signal (S OUT ) of the sensor (30) in the adapted operating mode. [10] Sensor arrangement (100) according to claim 9, wherein the processing device (50) is configured to control the operating mode of a heating element (34) and to read a pressure sensor (33) and / or a temperature sensor (35) coupled to the sensor chamber (31) of the sensor. [11] Sensor arrangement (100) according to one of the preceding claims, wherein the first micropump (10) has several micropump elements in a cascaded arrangement and / or wherein the second micropump (20) has several micropump elements in a cascaded arrangement. [12] Sensor arrangement (100) according to one of claims 9 to 11, wherein the processing device (50) is configured to (1.) control the operating modes of the first and second micropump (10, 20) to adjust the fluid pressure in the sensor chamber (31) and / or the fluid flow rate through the sensor chamber (31), (2.) control the heating element (34) to adjust different temperatures in the sensor chamber (31) and (3.) read out the sensor output signal (SOUT) at the different temperatures. [13] Sensor arrangement (100) according to claim 12, wherein the processing device (50) is configured to determine a sensor matrix that provides information (1.) about the read-out sensor output signal (S OUT ), (2.) to the operating mode of the first and second micropump (10, 20) and (3.) to the different temperatures in the sensor chamber (31). [14] Sensor arrangement (100) according to claim 13, wherein the processing device (50) is further configured to determine the sensor matrix which includes information (4.) about the measured pressure in the sensor chamber (31). [15] Sensor arrangement (100) according to claim 13 or 14, wherein the processing device (50) is further configured to determine the sensor matrix which includes information (5.) about the defined fluid flow through the sensor chamber (31). [16] Sensor arrangement (100) according to one of claims 9 to 15, wherein the processing device (50) is configured to provide a customized actuation with a square wave or sine wave actuation signal (S 10 , S 20 ) to provide for the first and second micropump (10, 20). [17] Sensor arrangement (100) according to any one of claims 9 to 16, wherein the processing device (50) is further configured to detect the presence, quantity or concentration of a target fluid (F T ) in the fluid (F) in the sensor chamber (31) on the basis of a resulting pressure oscillation profile of the fluid (F) in the sensor chamber (31). [18] Sensor arrangement (100) according to one of the preceding claims, wherein the first and second micropump (10, 20), the sensor (30) and the processing device (50) are integrated with a semiconductor substrate. [19] Sensor arrangement (100) according to one of the preceding claims, wherein the sensor element (32) is sensitive to a chemical or physical condition of the fluid (F) in the sensor chamber (31). [20] Sensor arrangement (100) according to one of the preceding claims, wherein the sensor element (32) is for a concentration of a target fluid (F T) is sensitive in the fluid (F) in the sensor chamber (31). [21] Sensor arrangement (100) according to one of the preceding claims, wherein the sensor element (32) is capable of detecting the presence, quantity and / or concentration of a target gas (F T ) is sensitive in a gas in the sensor chamber (31), wherein the target gas (F T ) a volatile organic compound (VOC), CO X , O X or NO X exhibits. [22] Sensor arrangement (100) according to one of the preceding claims, wherein the sensor element (32) is a metal oxide-based VOC sensor. [23] Sensor arrangement (100) according to one of the preceding claims, wherein the sensor element (32) is an electrochemical sensor with a liquid or solid electrolyte material. [24] Sensor arrangement (100) according to one of the preceding claims, wherein the sensor element (32) is sensitive to a concentration of particle matter in the fluid (F) in the sensor chamber (31). [25] Method (300) for measuring a quantity or concentration of a target fluid (F T ) in a fluid (F) with the sensor arrangement (100) according to one of the preceding claims, wherein the method comprises: Adjusting (310) the operating mode of the first and second micropump (10, 20) and Reading (320) the sensor output signal (S OUT ) of the sensor (30) in the set operating mode. [26] Method (300) according to claim 25, further comprising: Setting (330) the temperature of the fluid (F) in the sensor chamber (31) and / or the sensor element (32) of the sensor (30) to provide different measurement temperatures in the sensor chamber (31); Measuring (340) the temperature in the sensor chamber (31) and Reading (350) the sensor output signal (S OUT ) at the different temperatures. [27] Method (300) according to claim 25 or 26, further comprising: Adjusting (360) the fluid pressure in the sensor chamber (31) and / or the fluid flow rate through the sensor chamber (31) to provide different fluid pressures in the sensor chamber (31) and / or different fluid flow rates through the sensor chamber (31), Measuring (370) the fluid pressure in the sensor chamber (31) and / or the fluid flow rate through the sensor chamber (31) and Reading (380) the sensor output signal (S OUT ) at the different fluid pressures in the sensor chamber (31) and / or the fluid flow rates through the sensor chamber (31). [28] Method (300) according to any one of claims 25 to 27, further comprising: Determine (390) a sensor matrix that provides information (1.) about the read sensor output signal (S) OUT ) and (2.) to the set operating mode of the first and second micropump (10, 20) includes. [29] Method (300) according to claim 28, further comprising: Determine (400) the sensor matrix which includes information (3.) about the different temperatures in the sensor chamber (31). [30] Method (300) according to claim 28 or 29, further comprising: Determine (410) the sensor matrix which includes information (4.) about the measured pressure in the sensor chamber (31). [31] Method (300) according to any one of claims 28 to 30, further comprising: Determine (420) the sensor matrix which includes information (5.) about the defined fluid flow through the sensor chamber (31). [32] Method (300) according to any one of claims 28 to 31, further comprising: Determining (430) the presence, quantity or concentration of a target fluid (F T ) in the fluid (F) in the sensor chamber (31) based on the resulting sensor matrix.

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