阅读说明：本技术 流体传感器 (Fluid sensor ) 是由 D·图姆波德 于 2021-05-06 设计创作，主要内容包括：本公开的各实施例总体上涉及流体传感器。流体传感器(10)包括：壳体结构(12),形成腔室(14)；IR发射器(18),被配置用于在腔室(14)中发射IR辐射(20),其中IR辐射(20)具有中心波长(λ-(0)),以用于提供IR辐射(20)与目标流体(F-(T))的相互作用,该相互作用导致腔室(14)中或壳体结构(12)中的温度变化(ΔT),该温度变化(ΔT)影响壳体结构(12)中的机械脉冲(22)；以及惯性检测传感器(24),被机械地耦合到壳体结构(12),以用于感测壳体结构(12)中的机械脉冲。(Embodiments of the present disclosure generally relate to fluid sensors. A fluid sensor (10) includes: a housing structure (12) forming a chamber (14); an IR emitter (18) configured for emitting IR radiation (20) in the chamber (14), wherein the IR radiation (20) has a central wavelength (λ [) 0 ) For providing IR radiation (20) with a target fluid (F) T ) Causing a temperature change (Δ T) in the chamber (14) or in the housing structure (12), which temperature change (Δ T) affects the mechanical impulse (22) in the housing structure (12); and an inertial detection sensor (24) mechanically coupled to the housing structure (12) for sensing the housingMechanical impulse in the structure (12).)

1. A fluid sensor (10) comprising:

a housing structure (12) forming a chamber (14),

an IR emitter (18) optically coupled to the housing structure (12) and configured for emitting IR radiation (20) in the chamber (14), wherein the IR radiation (20) has a central wavelength (λ [)₀) For providing the IR radiation (20) with a target fluid (F)_T) Causes a temperature change (Δ T) in the chamber (14) or in the housing structure (12), which temperature change (Δ T) affects a mechanical impulse (22) in the housing structure (12), and

an inertial detection sensor (24) mechanically coupled to the housing structure (12) for sensing the mechanical pulses in the housing structure (12).

2. The fluid sensor (10) of claim 1, wherein the IR radiation (20) interacts with the target fluid (F)_T) Is the absorption of the IR radiation (20) by the target fluid, and wherein the IR radiation (20) is absorbed by the target fluid (F)_T) The absorption of the IR radiation (20) results in the target fluid (F)_T) Thereby causing a pressure change in the chamber (14) which affects the mechanical impulse in the housing structure (12).

3. The fluid sensor (10) of claim 1 or claim 2, wherein the IR radiation (20) interacts with the target fluid (F)_T) Is an absorption of the IR radiation (20) by the target fluid, the absorption resulting in the temperature change in the housing structure (12), wherein the heating of the housing structure (12) is inversely proportional to the absorption of the IR radiation (20) by the target fluid.

4. The fluid sensor (10) of claim 3, wherein the heating of the housing structure (12) by the IR radiation (20) reduces the target fluid (F)_T) IR radiation absorption amount of (a).

5. Fluid sensor (10) according to any of the preceding claims, wherein the housing structure (12) comprises a mechanical pulse amplification structure (26) for providing a mechanical amplification of the mechanical pulse in the housing structure (12), wherein the amplification of the mechanical pulse depends on the temperature change of the housing structure (12) or the temperature change of a region of the housing structure (12), the region of the housing structure (12) being thermally coupled to the mechanical vibration amplification structure (26).

6. The fluid sensor (10) of any one of the preceding claims, wherein the inertial detection sensor (24) comprises an accelerometer configured to provide a detector output signal (S) based on an amplitude of the mechanical pulses (20) of the housing structure (12)_OUT1) Receiving the mechanical pulse (20) of the housing structure (12) by the inertial detection sensor (24) being mechanically coupled to the housing structure (12).

7. The fluid sensor (10) of claim 6, wherein the accelerometer (24) comprises a piezoelectric sensor structure and/or a capacitive sensor structure for sensing the mechanical impulse (20) in the housing structure (12).

8. The fluid sensor (10) of any one of the preceding claims, wherein the inertial detection sensor comprises a suspended mechanical sensor structure having a mechanical resonance frequency in a range between 5Hz and 25kHz, in particular in a range between 5Hz and 100 Hz.

9. The fluid sensor (10) of any one of the preceding claims, wherein the housing structure (12) comprises a cover structure (12-1), the cover structure (12-1) being mechanically coupled to a substrate (12-2), wherein the inertial detection sensor (24) is mechanically coupled to the cover structure (12-1) or the substrate (12-2).

10. The fluid sensor (10) of any one of the preceding claims, further comprising:

a plurality of inertial detection sensors (24) mechanically coupled to the housing structure (12) for sensing the mechanical pulses (20) in the housing structure (12).

11. The fluid sensor (10) of claim 10, wherein at least one of the plurality of inertial detection sensors (24) is disposed at the housing structure (12) within the chamber (14) or at least one of the plurality of inertial detection sensors (24) is disposed at the housing structure (12) outside of the chamber (14).

12. The fluid sensor (10) of claim 10, wherein at least one of the plurality of inertial detection sensors (24) is disposed at the housing structure (12) within the chamber (14) and at least one of the plurality of inertial detection sensors (24) is disposed at the housing structure (12) outside of the chamber (14).

13. The fluid sensor (10) of any one of the preceding claims, further comprising:

a differential pressure sensor (28) arranged in the chamber (14) of the housing structure (12) to provide a further detector output signal (S) based on the pressure variation generated in the chamber (14) of the housing structure (12) by the IR radiation (20)_OUT2)。

14. The fluid sensor (10) of any one of the preceding claims, further comprising:

a processing circuit (30) for providing a time-varying or pulsed excitation signal (S) to the IR emitter (18)₁₈) And for reading out an output signal (S) for providing the fluid sensor (10)₁₀) The inertia detection sensor (24), the fluid sensor (10) outputting a signal (S)₁₀) Providing a fluid (F) in connection with said environment_E) The target fluid component (F) of (1)_T) Information of the concentration of (a).

15. The fluid sensor (10) of any one of the preceding claims, wherein the housing structure (12) comprises a passage to the chamber (14) for containing a target fluid (F)_T) Ambient fluid of composition (F)_E) Of the fluid channel (16).

16. The fluid sensor (10) according to any one of claims 1 to 14, wherein the chamber (14) in the housing structure (12) is hermetically closed and comprises the target fluid component (F)_T)。

17. The fluid sensor (10) according to any one of the preceding claims, wherein the cover (12-1) and/or a portion of the substrate (12-2) and/or a portion of the inertial detection sensor (24) form a radiation receiving section (12-3), the radiation receiving section (12-3) being arranged such that a temperature change Δ T in the radiation receiving section (12-3) affects the mechanical pulse (22).

18. A fluid sensor (10) comprising:

a housing structure (12) forming a chamber (14),

an inertial detection sensor (24), wherein a portion of the inertial detection sensor (24) forms a radiation receiving section (12-3), and

an IR emitter (18) optically coupled to the housing structure(12) And is configured for emitting IR radiation (20) in the chamber (14), wherein the IR radiation (20) has a central wavelength (λ [)₀) For providing the IR radiation (20) with a target fluid (F)_T) An interaction causing a temperature change (Δ T) in the radiation receiving section (12-3) of the inertial detection sensor (24), the temperature change (Δ T) affecting a mechanical pulse (22) in the inertial detection sensor (24),

wherein the inertial detection sensor (24) is arranged for sensing the mechanical pulse.

19. The fluid sensor (10) of claim 18, wherein the IR radiation (20) interacts with the target fluid (F)_T) Is an absorption of the IR radiation (20) by the target fluid, the absorption resulting in the temperature change in the radiation receiving section (12-3) of the inertial detection sensor (24), wherein heating of the radiation receiving section (12-3) of the inertial detection sensor (24) is with the target fluid (F)_T) The absorption of the IR radiation (20) is inversely proportional.

20. The fluid sensor (10) of claim 18 or claim 19, wherein the inertial detection sensor (24) comprises an accelerometer configured to provide a detector output signal (S) based on an amplitude of the mechanical pulse (20) in the radiation receiving section (12-3) of the inertial detection sensor (24)_OUT1)。

Technical Field

Embodiments of the present disclosure relate to the field of fluid sensors (such as gas sensors or liquid sensors). More particularly, embodiments relate to the field of acceleration sensor based PAS systems, and in particular, to photoacoustic sensors that pick up sound or mechanical pulses (e.g., vibrations) using acceleration sensors or inertial sensors or resonant sensors.

Background

Sensing of environmental parameters (e.g., ambient gas components) in the ambient atmosphere, such as noise, sound, temperature, and gas, is becoming increasingly important in the implementation of appropriate sensors in mobile devices, home automation (such as smart homes), and the automotive industry. Harmful gas concentrations may occur due to air pollution and/or failure of certain electrical or electronic equipment. However, the health of humans or animals is strongly influenced by the quality of the air. Therefore, gas detection and gas evaluation in the ambient atmosphere by means of inexpensive, always available and connected sensors is the subject of the future. However, with the widespread use of sensors, there is also a particular need to be able to produce such sensors as cheaply as possible, and thus cost-effective. However, the reliability and accuracy of the sensor should still be maintained or even improved.

In particular, the field of monitoring the air quality in our environment is receiving increasing attention. A typical optical sensor, such as a photoacoustic sensor (PAS), includes: a radiation source, a filter element for wavelength selection, a detector and a sampling area where light between the source and the detector interacts with the ambient medium.

In this field, an open type photoacoustic sensor or a closed type photoacoustic sensor is used. Open photoacoustic sensors use either a resonance method to detect gas concentration or a detector diaphragm to directly regulate gas diffusion and separate the measurement chamber from the environment. Closed photoacoustic sensors typically use reference cells filled with a target gas, which are typically separated from the detector via an absorption path of determined concentration. PAS sensors generate sound waves and detect time-varying amplitudes via an acoustic transducer, such as a microphone.

In general, there is a need in the art for a method of implementing a fluid sensor having reduced manufacturing requirements and providing sufficient sensitivity to a target fluid to be detected by the fluid sensor apparatus.

This need may be solved by a fluid sensor according to claim 1. Further, specific implementations of the fluid sensor are defined in the dependent claims.

Disclosure of Invention

According to an embodiment, a fluid sensor includes: a housing structure forming a chamber for a target fluid composition; an IR emitter optically coupled to the housing structure and configured for emitting IR radiation in the chamber, wherein the IR radiation has a central wavelength for providing an interaction of the IR radiation with a target fluid, the interaction resulting in a temperature change in the chamber or in the housing structure, the temperature change affecting a mechanical pulse in the housing structure; and an inertial detection sensor mechanically coupled to the housing structure for sensing mechanical impulses in the housing structure.

According to an embodiment, the interaction of the IR radiation with the target fluid is an absorption of the IR radiation by the target fluid, and wherein the absorption of the IR radiation by the target fluid causes a temperature change of the target fluid and thus a pressure change in the chamber, which affects the mechanical impulse in the housing structure. Thus, the amplitude of the mechanical pulses in the shell structure is proportional to the absorption of the IR radiation by the target fluid. Therefore, the output signal of the inertial detection sensor is proportional to the absorption of IR radiation by the target fluid, and the fluid sensor has a PAS sensor function (PAS ═ photoacoustic spectrometer).

According to an embodiment, the interaction of the IR radiation with the target fluid is an absorption of the IR radiation by the target fluid, which results in a temperature change or a thermal pulse in the shell structure, wherein the heating of the shell structure and the amplitude of the mechanical pulse generated in the shell structure is inversely proportional to the absorption of the IR radiation by the target fluid. Therefore, the output signal of the inertial detection sensor is inversely proportional to the absorption of IR radiation by the target fluid, and the fluid sensor has an NDIR sensor function (NDIR ═ non-dispersive IR).

According to an embodiment, a fluid sensor includes: a housing structure forming a chamber; an inertial detection sensor, wherein a portion of the inertial detection sensor forms a radiation receiving section; and an IR emitter optically coupled to the housing structure and configured to emit IR radiation in the chamber, wherein the IR radiation has a central wavelength λ₀For providing an interaction of the IR radiation with the target fluid, which interaction results in a temperature change in a radiation receiving section of the inertial detection sensor, which temperature change affects the mechanical pulses in the inertial detection sensor, wherein the inertial detection sensor is arranged for sensing the mechanical pulses.

Drawings

Embodiments of the present disclosure are described in more detail below with reference to the attached drawing figures, wherein:

FIG. 1 shows a schematic cross-sectional view of a fluid sensor according to an embodiment;

FIG. 2 shows a schematic cross-sectional view of a fluid sensor according to a further embodiment;

FIG. 3 shows a schematic cross-sectional view of a fluid sensor according to a further embodiment;

FIG. 4 shows a schematic cross-sectional view of a fluid sensor according to a further embodiment;

fig. 5 shows a schematic cross-sectional view of a fluid sensor according to a further embodiment.

Before discussing the present embodiments in more detail using the drawings, it should be noted that in the drawings and the description, the same elements and elements having the same functions and/or the same technical or physical effects are generally provided with the same reference numerals or the same name identifications so that the descriptions of the elements and their functions in different embodiments can be interchanged with each other or applied to each other in different embodiments.

Detailed Description

Embodiments will be discussed in detail in the following description, however, it should be understood that embodiments provide many applicable concepts that can be embodied in a wide variety of semiconductor devices. The specific embodiments discussed are merely illustrative of specific ways to make and use the concepts, and do not limit the scope of the embodiments. In the description of the embodiments below, the same or similar elements having the same function have the same reference numerals or the same names, and the description of these elements will not be repeated in each embodiment. Furthermore, the features of the different embodiments described hereinafter may be combined with each other, unless specifically noted otherwise.

It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being "directly" connected ("connected" or "coupled") to another element, there are no intervening elements present. Other terms used to describe the relationship between elements should also be constructed in a similar manner (e.g., "between … …" and "directly between … …", "adjacent" and "directly adjacent", and "on … …" and "directly on … …", etc.).

To facilitate the description of the different embodiments, the figures include a cartesian coordinate system x, y, z, wherein an x-y plane corresponds to (i.e., is parallel to) the first major surface section of the base plate (the "reference plane" xy plane), wherein a direction vertically upwards with respect to the reference plane (x-y plane) corresponds to a "+ z" direction, and wherein a direction vertically downwards with respect to the reference plane (x-y plane) corresponds to a "-z" direction. In the following description, the term "lateral" refers to a direction parallel to the x-direction and/or the y-direction (i.e., parallel to the x-y plane), wherein the term "vertical" refers to a direction parallel to the z-direction. In fig. 1-5, the drawing plane is parallel to the x-z plane.

Fig. 1 shows a fluid sensor 10 according to an embodiment. According to an embodiment, the fluid sensor 10 includes a housing structure (or package) 12. The housing structure 12 forms a chamber 14. The fluid sensor 10 further comprises an IR emitter 18, the IR emitter 18 being optically coupled to the housing structure 12 and configured for emitting IR radiation 20 in the chamber 14, wherein the IR radiation 20 has a central wavelength λ₀For providing IR radiation 20 with the target fluid F_TThereby causing a temperature change at in the chamber 14 that affects the mechanical impulse 22 in the housing structure 12. The fluid sensor 10 also includes an inertial detection sensor 24 mechanically coupled to the housing structure 12 for sensing mechanical impulses in the housing structure 12.

The housing structure 12 may include a mechanically bonded cover element 12-1 and a base plate 12-2. As exemplarily shown in fig. 1, the IR emitter 18 may be disposed inside the chamber 14. The IR emitter 18 may also be arranged outside the chamber 14, according to further embodiments below. Accordingly, the IR emitter 18 is optically coupled to the housing structure 12 and is configured to emit IR radiation 20 in the chamber 14, wherein the IR radiation 20 has a central wavelength λ₀For providing IR radiation 20 with a target fluid component F_TThereby causing a temperature change at of the fluid atmosphere in the chamber 14 or causing a temperature change at in at least a portion 12-3 of the housing structure 12. This temperature change Δ T of the fluid atmosphere in the chamber 14 or in at least a part of the housing structure 12 affects or causes a mechanical impulse 22 in the housing structure 12. The fluid sensor 10 also includes an inertial detection sensor 24 (e.g., an accelerometer or gyroscope, etc.) mechanically coupled to the housing structure 12 for sensing the mechanical pulses 22 in the housing structure 12. Thus, embodiments provide photoacoustic pickup via the inertial detection sensor 24 (such as an accelerometer).

According to an embodiment, the fluid sensor 10 is arranged for sensing the surrounding atmosphere F_ETarget fluid or target fluid component F in (e.g. ambient medium)_TThe amount or concentration of. In this context, the term fluid may relate to a liquid or a gas. In the case where the ambient medium relates to ambient air, the target fluid may relate to a fluid present in ambient air (ambient atmosphere) F_ETarget gas or target gas component F in (1)_T. The present concept is equally applicable to sensing an environmental medium F_ETarget liquid or target liquid component F in ambient gas or ambient liquid_T. Herein, gas and liquid are collectively referred to as fluid.

According to an embodiment, the mechanical or structural pulse 22 may be considered as a local, mechanical or structural deformation of at least one region of the shell structure 12, wherein the mechanical pulse 22 propagates or propagates in the shell structure 12. Thus, the mechanical pulse 22 can propagate or propagate as structure-borne sound or structure-borne sound in the housing structure 12. The plurality of mechanical pulses or series of mechanical pulses 22 may also be referred to as mechanical vibrations.

According to an embodiment, the inertial detection sensor 24 may comprise an accelerometer configured to provide the detector output signal S based on the amplitude of the mechanical pulse 22 in the housing structure 12_OUT1The mechanical pulse 22 is received by an inertial detection sensor 24 mechanically coupled to the housing structure 12. For example, accelerometer 24 may include provisions for sensingA piezoelectric sensor structure and/or a capacitive sensor structure of mechanical impulses 22 in the housing structure 12.

The main effects are as follows: as described above, the IR radiation 20 interacts with the target fluid or target fluid component F in the chamber 14_TMay cause a change in temperature deltat of the fluid atmosphere in the chamber 14 (as a first effect). Due to the IR radiation 20 and the target fluid F_TOf the target fluid F_TAbsorbs light (═ IR radiation 20) and generates a pressure pulse ap in chamber 14 due to a temperature change at of the fluid atmosphere in chamber 14. The pressure pulses Δ P are converted into structural pulses or vibrations 22 in the housing structure 12 and signal pickup in the form of pressure pulse (═ sound) detection is effected by means of an inertial sensor 24 (e.g. an accelerometer).

This effect can be considered as the first (primary) measurement effect, in which the IR radiation 20 interacts with the target fluid F_TIs passed through the target fluid F_TAbsorption of IR radiation 20 and wherein the target fluid F is passed_TAbsorption of the IR radiation 20 results in the target fluid F_TAnd hence a pressure change deltap in the chamber 14, which change affects the mechanical impulse 22 in the housing structure 12.

The implementation of a measurement for sensing a primary effect (measurement setup) may require a relatively "closed" housing 12 for generating the pressure pulse in the chamber 14, since the pressure pulse Δ P is in conjunction with the fluid atmosphere F in the chamber 14_EOf (2) a target fluid F_TIs proportional or proportional. Thus, the amplitude of the mechanical pulse 22 in the housing structure 12 or inertial detection sensor 24 is proportional to the absorption of the IR radiation 20 by the target fluid. Therefore, the output signal S of the inertia detection sensor 24_OUT1And through the target fluid F_TThe absorption of IR radiation 20 is proportional and the fluid sensor 10 has a PAS sensor function (PAS ═ photoacoustic spectrometer).

According to the embodiment of FIG. 1, the housing structure 12 may include a port to the chamber 14 for containing the target fluid composition F_TOf an ambient fluid F_EOf the fluid channel 16. Thus, for the ambient fluid "F_E"fluid passageThe channel 16 may be arranged for providing a fluid exchange between the environment of the fluid sensor 10 and the chamber 14 of the fluid sensor 10, wherein the fluid channel 16 may be arranged as a low pass filter for the pressure pulses Δ Ρ in the chamber 14 with respect to the environment, i.e. a fast pressure change Δ Ρ in the chamber 14 with respect to the environment is substantially maintained in the chamber 14 and a slow pressure change Δ Ρ in the chamber 14 with respect to the environment may be balanced with the environment.

Secondary effects: as described above, the IR radiation 20 interacts with the target fluid component F_TMay cause a temperature change at of at least a portion 12-3 of the housing structure 12 or a portion of the inertial detection sensor 24, which affects the mechanical impulse 22 in the housing structure 12 or in the inertial detection sensor 24, respectively. IR radiation 20 and target fluid F in the chamber 14_TThe further measuring effect of the interaction of (a) is through the target fluid F_TAbsorption of IR radiation, which leads to a temperature change Δ T (thermal pulse) in the housing structure 12 (i.e. in at least a part of the housing structure 12 or the entire housing structure 12). Local heating of the shell structure 12 and passage of the target fluid F in the chamber 14_TThe absorption of IR radiation 20 is inversely proportional. Heating of the housing structure 12 by the IR radiation 20 reduces the target fluid F_TIR radiation absorption amount of (a).

More specifically, due to the target fluid F_TThe amount of absorption of the IR radiation, the target fluid F in the chamber 14_TThe higher the concentration of (b), the lower the (local) heating of the housing structure 12 by the IR radiation 20. Thus, the temperature change Δ T is related to the passage of the target fluid F in the chamber 14_TThe absorption of the IR radiation 20 is inversely proportional, so the localized heating of the shell structure 12 and the resulting heat pulse 22 is the target fluid F_TIn an ambient fluid F_EA measure of the concentration of (a).

As exemplarily shown in fig. 1, the chamber 14 may be arranged for providing an optical interaction path for having a central wavelength λ₀With the target fluid F in the chamber 14 and the narrow band electromagnetic radiation 20 of_TThe interaction of (a). Part of the housing structure 12 or part of the inertial detection sensor 24The radiation receiving region 12-3 may be formed. Due to the heating of the housing structure 12 by the IR radiation 20, the passage of the target fluid F is reduced_TAnd thus an interior portion of the housing structure 12 (e.g., a portion of the cover 12-1 or the base plate 12-2) or a portion of the inertial detection sensor 24 may form the radiation receiving section 12-3.

As exemplarily shown in fig. 1, the radiation receiving area 12-3 may be provided in or on the housing structure 12, i.e. in or on at least one of the cover 12-1 and the substrate 12-2. As further shown in fig. 1, the radiation receiving area 12-3 may optionally be part of the inertial detection sensor 24 itself, such as (if the inertial detection sensor 24 is provided inside the package 12) a surface area of the inertial detection sensor 24 in the chamber 14. Thus, the radiation-receiving region 12-3 is disposed inside the enclosure 12 surrounding the cavity 14, as well as in the lid 12-1 or on the lid 12-1, in the substrate 12-2 or on the substrate 12-2, and/or in the inertial detection sensor 24 or on the inertial detection sensor 24.

Based on the heating caused by the IR radiation 20, the radiation receiving section 12-3 can provide thermally induced mechanical pulses 22 based on the signal strength of the narrow band electromagnetic radiation 20 that has traversed the optical interaction path P in the chamber 14 and is received by the radiation receiving section 12-3. Heating of the radiation receiving section 12-3 of the housing structure 12 or heating of the inertial detection sensor 24 and passage of the target fluid F in the chamber 14_TThe absorption of IR radiation 20 is inversely proportional. Therefore, the output signal S of the inertia detection sensor 24_OUT1And through the target fluid F_TThe absorption of the IR radiation 20 is inversely proportional and the fluid sensor 10 has an NDIR sensor function (NDIR ═ non-dispersive IR).

Due to the IR radiation 20 and the target fluid F_TOf the target fluid F_TAbsorbs light (═ IR radiation 20) and, due to the temperature change Δ T of the radiation receiving section 12-3, a heat pulse Δ P is generated in the material of the housing structure 12 or in the inertial detection sensor 24. Thus, the thermal energy is converted into structural deformation (e.g., localized structural deformation) and/or into a housing structure 12 or inertial detection sensorStructural pulses or vibrations in 24 and signal pickup in the form of pressure pulse detection is achieved with an inertial sensor 24 (e.g., an accelerometer).

The realization of a measurement for sensing a secondary effect (measurement setup) may require a relatively "open" housing 12 for generating a heat pulse in the housing structure 12 or in the inertial detection sensor 24 and for "avoiding" a pressure pulse in the chamber 14, since the thermally induced mechanical pulse in the housing structure 12 and the fluid atmosphere F in the chamber 14_EOf (2) a target fluid F_TIs inversely proportional.

Thus, for the ambient fluid "F_E"the fluid channel 16 may be arranged for providing a relatively" free "fluid exchange between the environment of the fluid sensor 10 and the chamber 14 of the fluid sensor 10, i.e. a slow and fast pressure change Δ P in the chamber 14 relative to the environment may be immediately in equilibrium with the environment, wherein pressure pulses Δ P in the chamber 14 may be substantially avoided.

According to embodiments (of primary and secondary effects), the housing structure 12 may comprise a passage 16 to the chamber 14 in the form of a fluid inlet or fluid opening 16. Thus, for a fluid including a target fluid or target fluid composition "F_T"ambient fluid" F_E", the chamber 14 is accessible through the fluid inlet 16. Depending on the embodiment, the passage 16 to the chamber 14 may also include perforated material as well as other structures (e.g., diffusers) or even more complex structures (such as fluid valves or fluid pumps). The diffuser 16 may include a perforated fluid permeable membrane and a reinforcing structure mechanically coupled with the perforated membrane for mechanically stiffening and/or stabilizing the perforated membrane (120). May pass through the passage 16 to the housing structure 12 (i.e., by allowing ambient fluid F to the chamber 14)_EStructural features 16 of the inlet) to regulate fluid dispersion and acoustic suppression (e.g., acoustic noise suppression) in the chamber 14.

According to an embodiment, the housing structure 12 may include a mechanical pulse amplification structure 26 at or near the cover 12-1, the substrate 12-2, or the radiation receiving section 12-3 of both the cover 12-1 and the substrate 12-2. The mechanical pulse amplification structure 26 may have at least one of a cantilever element, a bi-metallic structure, a diaphragm element, or any other sensitive vibrating structure for providing mechanical amplification of the mechanical pulse 22 (i.e., the amplitude of the mechanical pulse 22 in the housing structure 12).

The enlarged region "1-1" of fig. 1 shows an exemplary mechanical pulse amplification structure 26 in the form of a cantilever element, e.g. a (small) artefact 26-1 on the cantilever with mechanical amplification for increasing the mechanical pulse 22.

The enlarged region "1-2" of fig. 1 shows an exemplary mechanical pulse amplification structure 26 in the form of a diaphragm-based resonant element. The mechanical pulse amplification structure (acceleration sensor) 26 may be implemented as a MEMS microphone, for example with a (small) artificial mass 26-1 on the membrane 26-2 for increasing the mechanical amplification of the mechanical pulse 22.

The amplification of the mechanical pulse 22 in the housing structure 12 may be a conversion of a temperature change Δ T (thermal pulse) in the housing structure 12 in an amplified mechanical pulse 22' with an increased amplitude when compared to the amplitude of the mechanical pulse 22 without amplification (thermal induction). Such an amplified mechanical pulse 22' is an easily detectable mechanical or physical quantity due to a temperature change Δ T in (the radiation receiving section 12-3 of) the housing structure 12. The amplification of the mechanical pulse 22 is dependent on the temperature change Δ T of the housing structure 12 or the temperature change Δ T of the region 12-3 of the housing structure 12, which region 12-3 of the housing structure 12 is thermally coupled to the mechanical vibration amplification structure 26.

According to further embodiments, the mechanical amplifier 26 may be a structure that follows the law of leverage, see for example the cantilever member 26 shown in the enlarged region "1-1" of FIG. 1. It may also be a structure that couples to the incompressible material following newton's law (e.g., the law of piston pressure). To obtain a fast transient effect, the coupling material can be assumed to be incompressible by exploiting its inertial force characteristics. One implementation may be a large diaphragm that senses vibration or pressure changes, coupled to a sensor device 10 having a closed volume, but with a smaller opening toward the sensor 10. If the liquid is incompressible or low compressible, the sensing diaphragm surface increases the signal relative to the detection opening with inverse properties. See, for example, diaphragm-based resonator element 26 shown in enlarged region "1-2" of figure 1.

Alternatively, the mechanical pulse or oscillation 22 can also be amplified by the lever law, in which the force is inversely proportional to the displacement. Alternatively, resonant structures may be used, such as mass spring dampers, e.g. levers, struts, diaphragms, etc. According to an embodiment, a mechanical amplification structure 26 (e.g., a lever) may be used to amplify the mechanical pulse or vibration 22. Furthermore, small (fast) bimetallic elements can also be used as oscillators for the mechanical amplifier arrangement 26.

According to embodiments, the emitter structure 18 may be configured to emit electromagnetic radiation 20 (e.g., thermal radiation) into the chamber 14 in a particular spectrum of wavelengths. A wavelength λ of the emitted narrow band electromagnetic (e.g., thermal) radiation 20 (e.g., narrow band thermal radiation)₀May depend on the fluid to be detected, i.e. the target fluid F in the ambient atmosphere_T。

At the target gas F to be detected_TIn the case of, for example, the target gas F_TCan comprise carbon monoxide CO and carbon dioxide CO₂Ozone O₃Nitrogen oxide NO_xMethane CH₄And the like. However, the target gas F to be detected_TThe list of (a) is not to be considered exhaustive. At the target liquid F to be detected_TIn the case of (2), the target liquid F_TCan comprise carbon monoxide CO and carbon dioxide CO₂Methane CH₄Ethanol, nitrogen dioxide NO₂Formaldehyde CH₂O and/or water vapor H₂And O. However, this list of liquids to be detected is not to be considered exhaustive.

Environmental medium F_EIt may be an ambient gas, such as an ambient gas or any gaseous atmosphere, or an ambient liquid (e.g. water in general, tap water or any liquid).

According to an embodiment, the emitter structure 18 may be configured to intermittently or periodically emit narrow band electromagnetic radiation 20. The transmitter structure 18 may also include a heat source and/or an infrared source 18-1, and optionally the wavelength selective structure 18-2 is configured to provide a narrow bandElectromagnetic radiation 20, e.g. having a central wavelength λ₀Of IR radiation pulses 20. Thus, comprising the target fluid F_TAmbient fluid F inside chamber 14 (e.g., target gas or target liquid)_EThe emitted electromagnetic radiation 20 is absorbed (e.g., by ambient gas or liquid), where this absorption by the fluid may produce a change (e.g., an increase) in temperature T in the chamber 14 or in the housing assembly 12 that affects a mechanical impulse or vibration 22 in the housing structure 12.

Target fluid F passing through the interior of the housing structure 12_TAnd the associated mechanical pulse, may depend on the type and amount of target fluid inside the chamber 14, and may follow the target fluid F_TAnd its concentration. The emitter structure 18 is arranged in the chamber 14 or optically coupled to the chamber 14.

In this specification, Infrared Radiation (IR) is mentioned as one non-limiting example of thermal radiation. Thermal radiation may be any radiation above absolute zero degrees, starting from a temperature of 0 ° kelvin. Generally, the infrared radiation may be a specific part of the thermal radiation. Additionally, a radiation source is mentioned and may comprise at least one of an infrared radiation source, a Light Emitting Diode (LED), a laser source and/or a heat source (thermal emitter).

The enlarged regions "1-3" of FIG. 1 show an exemplary IR emitter structure 18. According to an embodiment, the IR emitter structure 18 may be formed as a thermal emitter (IR source) comprising a separate membrane 19-1 supported by an emitter substrate 19-2, wherein the separate membrane 19-1 comprises a conductive central portion "S" which may be arranged on the separate membrane 19-1 or embedded in the separate membrane 19-1, and which may be arranged on an emitter chamber 19-3 in the emitter substrate 19-2.

The (optional) wavelength selective structure 18-2 is arranged for filtering the broadband IR radiation λ emitted by the thermal emitter 18-1 and for emitting narrowband IR radiation 20 into the chamber 14. Thus, for example, the wavelength selective structure (IR filter) 18-2 is configured to provide a wavelength having a center wavelength λ₀Of the narrow band IR radiation 20, the central wavelength lambda₀Fall intoTarget fluid composition F_TIn the absorption spectrum of (a). The wavelength selective structure 18-2 may be formed as an IR filter (e.g. a Fabry-Perot filter element) or as a plasmonic structure (e.g. a plasmonic resonator for the emitted IR radiation).

According to an embodiment, an inertial detection sensor 24 (e.g., an accelerometer or gyroscope, etc.) is mechanically coupled or bonded to the housing structure 12 for sensing the mechanical impulse 22 in the housing structure 12. The inertial detection sensor 24 may comprise a suspended mechanical sensor structure having a mechanical resonant frequency between 5Hz and 25kHz or between 5Hz and 100 Hz. The suspended mechanical sensor structure, which is deflectable relative to the mechanical impulse 22 in the housing structure 12, may have a mechanical resonant frequency, for example, within the frequency range of the time-varying or pulsed IR radiation 20 of the infrared source 18 or within the frequency range of harmonics produced by the time-varying or pulsed IR radiation 20 of the infrared source 18.

According to an embodiment, a MEMS microphone may be used as the acceleration sensor 24, wherein the resonance of the MEMS microphone is above or within the frequency range of the time-varying or pulsed IR radiation 20 of the infrared source 18, but the MEMS microphone may still be used to pick up mechanical vibrations in a wide frequency range (e.g. between 5Hz and 25 kHz). MEMS microphones are also capable of detecting acoustic information and therefore are capable of sensing a "broad" frequency spectrum.

According to an embodiment, the housing structure 12 includes a cover structure 12-1, the cover structure 12-1 being mechanically coupled or bonded to a base plate or element 12-2, wherein the inertial detection sensor 24 is mechanically coupled to the cover structure 12-1 and/or the base plate 12-2. An inertial detection sensor 24 is arranged at a position of the housing structure 12 that allows receiving and detecting the mechanical impulse 22 in the housing structure 12. Thus, the inertial detection sensor 24 may be arranged at a position of the housing structure 12 that provides a relatively high amplitude of the mechanical pulse 22 when compared to other parts of the housing structure 12.

As exemplarily shown in fig. 1 as an optional position, the inertial detection sensor 24 may be arranged at the housing structure 12 inside or outside the chamber 14. In case the inertial detection sensor 24 is arranged outside the chamber 14, an additional housing structure 13 may be provided for covering the inertial detection sensor 24, the additional housing structure 13 comprising a substrate 12-2 and a further cover structure 13-1, the additional housing structure 13 being mechanically coupled or bonded to the substrate or base element 12-2.

According to embodiments, the IR source 18 and the inertial detector 24 may be part of the same physical device surrounded by the housing structure 12. Where the fluid sensor 10 is part of a module (e.g., a taller lever assembly), an additional housing surrounding the module may additionally be provided.

According to an embodiment, the fluid sensor may optionally comprise a differential pressure sensor 28 (e.g. a MEMS microphone) arranged in the chamber 14 of the housing structure 12 to provide a further detector output signal S based on the pressure change Δ P_OUT2A pressure change Δ P is generated in the chamber 14 of the housing structure 12 by means of the IR radiator 20. Thus, the pressure change Δ Ρ may be additionally detected by the acoustic transducer 28 (e.g., a MEMS microphone inside the chamber or PAS volume 14), such that the differential pressure sensor 28 may form a PAS sensor (PAS photoacoustic spectrometer).

According to an embodiment, the fluid sensor 10 may include an inertial detection sensor 24, which inertial detection sensor 24 may be mechanically coupled to the housing structure and additionally include an acoustic transducer 28 (e.g., a MEMS microphone). According to an embodiment, the heat emitter 18 and the acoustic transducer 28 may be arranged inside the mutual measurement chamber 14. According to a further embodiment, the heat emitter 18, the inertial sensor 24 and the acoustic transducer 28 are arranged inside a common measurement chamber 14.

According to an embodiment, the fluid sensor may optionally include processing circuitry or a controller 30 for providing a time-varying or pulsed excitation signal S to the IR emitter 18₁₈And for reading out and optionally processing the corresponding output signal S of the inertial detection sensor 24₁₀And for providing a fluid sensor output signal S₁₀The signal having a signal related to the ambient fluid F in the chamber 14 of the housing structure 12_ETarget fluid component F in (1)_TConcentration of (2)The information of (1). The processing circuit 30 may be formed by an ASIC (application specific integrated circuit).

Based on time-varying or pulsed excitation signals S from the processing circuit 30₁₈The IR emitter 18 is configured for emitting IR radiation 20 into the chamber 14 in a pulsed manner and for influencing mechanical pulses or vibrations 22 in the housing structure 12.

The processing circuit 30 may also be configured to read out and optionally process the output signal S of the respective differential pressure sensor 28_OUT2To provide a fluid having a composition F related to the target fluid_TFluid sensor output signal S of concentration information₁₀。

According to an embodiment, the processing circuit 30 may be configured for detecting the output signal S of the sensor 24 based on inertia_OUT1And corresponding output signal S of the differential pressure sensor 28_OUT2To provide a fluid having a target fluid composition F_TFluid sensor output signal S of concentration information₁₀. Thus, since the fluid detection is based on two different physical effects and associated measurement principles, a reliable fluid sensor output signal S may be achieved₁₀。

In accordance with the above embodiments, the fluid sensor 10 (e.g., photoacoustic sensor (PAS)) may be based on MEMS technology and may include a chopped MEMS infrared emitting heater 18-1, an inertial sensor 24, an (optional) optical filter 18-2 for wavelength selective heating, and a housing 12. The system 10 may be operated by an internal ASIC 30, the internal ASIC 30 providing a heater (emitter) chopping signal (e.g., current) S₁₈And the output signal S of the inertia detection sensor 24_OUT1And optionally the output signal S of the differential pressure sensor 28_OUT2The structural vibration reading of (1).

The signal connections between the processing circuitry 30 and the inertial sensor 24 (and optionally the differential pressure sensor 28 and the heat emitter 18) are primarily shown only in fig. 1.

The core of the present concept can be seen when a MEMS inertial (acceleration) sensor 24 is combined with an optional infrared source 18 (e.g., infrared heater 18-1) and an optical filter 18-2 (e.g., in a single (same) housing 12 or in a shared (e.g., two or more) housings 12, 13).

Thus, embodiments of the present fluid sensor 10 allow for environmental atmosphere F_EAccurate and real-time fluid detection and assessment, i.e., effective monitoring of ambient air conditions and rapid detection of air pollution, is performed to meet the growing health concerns. Furthermore, the fluid sensor 10 also offers significant potential for energy efficiency in buildings, for example, for HVAC systems (HVAC ═ heating, ventilation, and air conditioning).

Fig. 2 shows a schematic cross-sectional view of a fluid sensor 10 according to a further embodiment. The above evaluation regarding the structure and function of the fluid sensor 10 with respect to fig. 1 is equally applicable to the fluid sensor 10 of fig. 2. The illustration of the fluid sensor 10 in fig. 2 differs from the illustration of the fluid sensor 10 in fig. 1 in that a plurality of alternative and exemplary positions a-K for placing at least one inertial detection sensor 24 are shown. More specifically, the fluid sensor 10 may include a plurality of inertial detection sensors 24 (24-a: sensor 24 at optional position a, … …, 24-K: sensor 24 at optional position K), the plurality of inertial detection sensors 24 being mechanically coupled to the housing structure 12 for sensing the mechanical impulse 20 in the housing structure 12.

The inertial detection sensors 24 are arranged or distributed at different locations of the housing structure 12, which allows for reliable reception and detection of the mechanical pulses 22 propagating in the housing structure 12. When compared to the illustration of fig. 2, the inertial detection sensors 24 may also be distributed at different positions of the housing structure 12 with respect to the z-direction (vertically distributed) or with respect to the y-direction or x-direction (laterally distributed) for reliably sensing the mechanical pulse 22.

According to an embodiment, at least one inertial detection sensor 24 of the inertial detection sensors 24 may be arranged at the housing structure 12 within the chamber 14. Additionally or alternatively, at least one of the inertial detection sensors 24 may be arranged at the housing structure 12 outside the chamber 14.

According to an embodiment, at least one of the inertial detection sensors 24 may be arranged at the housing structure 12 within the chamber 14, wherein at least one of the inertial detection sensors 24 may be arranged at the housing structure 12 outside the chamber 24.

According to an embodiment, at least one of the inertial detection sensors 24 may be arranged at the housing structure 12 on the first main surface area 12-2A of the substrate 12-2 (within the chamber 14 or outside the chamber 14). Additionally or alternatively, at least one of the inertial detection sensors 24 may be disposed at the housing structure 12 on the second major surface region 12-2B of the substrate 12-2 (outside of the chamber 14).

According to an embodiment, at least one of the inertial detection sensors 24 may be arranged at the housing structure 12 on the first main surface area 12-1A of the cover 12-1 (within the chamber 14 or outside the chamber 14). Additionally or alternatively, at least one of the inertial detection sensors 24 may be disposed at the housing structure 12 on the second major surface region 12-1B of the cover 12-2 (outside of the chamber 14).

In this configuration, the fluid sensor 10 of fig. 1-2 may be used as an open PAS system.

Fig. 3 and 4 show schematic cross-sectional views of a fluid sensor 10 according to further embodiments. The arrangement of the fluid sensor 10 of fig. 3 and 4 differs from the arrangement of the fluid sensor 10 of fig. 1 and 2 in that the emitter structure 18 of the fluid sensor 10 is placed outside the chamber 14. The evaluations described above in connection with fig. 1 and 2 in relation to the structure and function of the further elements of the fluid sensor 10 are equally applicable to the fluid sensor 10 described below. More specifically, the IR emitter 18 is configured to emit or couple IR radiation or pulses of IR radiation 20 into the chamber 14, optionally via the window 18-3 or waveguide 18-4, and the IR emitter 18 is disposed outside of the chamber 14, the IR radiation or pulses of IR radiation 20 affecting mechanical pulses 22 in a housing structure or inertial detection sensor 24.

The emitter structure 18 may also include a heat source and/or an infrared source 18-1, and optionally a wavelengthA wavelength selective structure 18-2, the wavelength selective structure 18-2 being configured for filtering broadband IR radiation 20 emitted by the thermal emitter 18-1 and being configured for having a central wavelength λ₀Into the chamber 14 (e.g., IR radiation pulses 20).

The wavelength selective structure 18-2 may be arranged at the infrared source 18-1, with narrowband IR radiation 20 coupled into the chamber 14 via an IR radiation transparent window 18-3. Additionally or alternatively to the wavelength selective structure 18-2, the window 18-3 may provide IR wavelength selectivity to the wavelength selective structure 18-2 for filtering broadband IR radiation λ emitted by the thermal emitter 18-1, such that the window 18-3 may form the wavelength selective structure 18-2 or may be part of the wavelength selective structure 18-2. Thus, at least one of the wavelength selective structure 18-2 (if present at the thermal emitter 18-1) and the window 18-3 provides an optical filter function that filters the broadband IR radiation λ emitted by the thermal emitter 18-1 and an optical filter function that provides/couples the narrowband IR radiation 20 into the chamber 14.

According to embodiments, the gap 32 may be designed to be (relatively) small (e.g. as small as possible), e.g. between 0 μm to 10 μm wide or between 6 μm to 8 μm wide, in order to create an interaction path P mainly within the chamber 14 for providing IR radiation and the target fluid F in the chamber 14_TWhich causes temperature changes in the chamber 14, in the housing structure 12, and/or in the inertial detection sensor 24. Thus, a more dominant IR radiation absorption is created within the chamber 14 rather than in the gap 32.

In this configuration, the fluid sensor 10 of fig. 3-4 may be used as an open PAS system. Any absorption of radiation in the chamber 14 will increase the temperature and can therefore be measured by pressure changes and vibrations (see above: primary and secondary effects).

According to further embodiments, the gap 32 may be designed to be (relatively) large (e.g. between 20 μm and 50mm wide, between 20 μm and 30mm wide or between 20 μm and 10mm wide) in order to create an interaction/absorption path P between the heat emitter 18 and the window 32. For example, due to the large absorption path, the large gap 32 is in the NDIR-based systemHigh resolution is provided in the system (closed configuration). The IR radiation then interacts with the target fluid F in the chamber 14_TCauses temperature changes in the chamber 14, in the housing structure 12, and/or in the inertial detection sensor 24. Thus, the radiation receiving area 12-3 is arranged inside the chamber 14 and in or on the cover 12-1, in or on the substrate 12-2, and/or in or on the inertial detection sensor 24 12-1. Temperature change or heat pulse in the radiation receiving region 12-3 with the target fluid F_TThe absorption of the IR radiation 20 is inversely proportional (see above: secondary effect).

Fig. 4 illustrates a configuration of the fluid sensor 10 in which the gap 32 is significantly reduced or eliminated. In the case where the gap 32 is omitted entirely, the window 18-3 may form a wavelength selective structure 18-2, wherein the emitter structure 18 may be disposed directly at the housing structure 12 (e.g., the cover 12-1) and/or mechanically coupled to the housing structure 12.

The arrangement of the emitter structure 18 in fig. 3 and 4 also ensures that the radiation coupled into the chamber 14 is of a central wavelength λ₀20 of the IR radiation.

Fig. 5 shows a schematic cross-sectional view of a fluid sensor 10 according to a further embodiment. The arrangement of the fluid sensor 10 of fig. 5 differs from the arrangement of the fluid sensor 10 of fig. 3 and 4 in that the chamber 14 in the housing structure 12 is hermetically closed and comprises a reference fluid component F_R. As shown in fig. 5, the IR emitter 18 is arranged outside the chamber 14 and is optically coupled to the chamber 14 for emitting IR radiation 20 in the chamber 14.

According to an embodiment, the fluid sensor 10 includes a housing structure (or package) 12. The housing structure 12 forms a chamber 14. The fluid sensor 10 further comprises an IR emitter 18, the IR emitter 18 being optically coupled to the housing structure 12 and configured for emitting IR radiation 20 in the chamber 14, wherein the IR radiation 20 has a central wavelength λ₀For providing IR radiation 20 with the target fluid F_TThereby causing a temperature change at in the chamber 14 or in the housing structure 12 that affects the mechanical impulse 22 in the housing structure 12. The fluid sensor 10 further includesAn inertial detection sensor 24 is included, the inertial detection sensor 24 being mechanically coupled to the housing structure 12 for sensing mechanical impulses in the housing structure 12.

The wavelength selective structure 18-2 is arranged at the infrared source 18-1, wherein narrowband IR radiation 20 is coupled into the cavity 14 via the IR radiation transparent window 18-3. In this configuration, the fluid sensor 10 of fig. 5 may be used as a closed PAS system having an interaction path P located at least partially outside of the chamber 14.

According to embodiments, the gap 32 may be designed to be (relatively) large (e.g. 20 μm to 5mm wide) in order to create an interaction/absorption path P between the heat emitter 18 and the window 32 for providing the IR radiation 20 and the ambient atmosphere F_EOf (2) a target fluid F_TThe interaction of (a).

The chamber 14 is hermetically closed and filled with a reference fluid composition F_RWherein reference fluid component F_RAbsorbs the remaining IR radiation 20 entering the chamber 14 and provides localized heating and/or a generated heat pulse 22 for a portion of the housing structure 12 and/or the inertial detection sensor 24. The locally heated and/or generated heat pulse 22 is an ambient fluid F_EOf (2) a target fluid F_TAnd with the ambient atmosphere F_EOf (2) a target fluid F_TThe absorption of IR radiation 20 is inversely proportional.

More specifically, in the ambient atmosphere F_EOf (2) a target fluid F_TIs higher due to passage through the target fluid F_TThe lower the amount of IR radiation 20 absorbed, the lower the amount of IR radiation 20 reaching the chamber 14, and the lower the localized heating and/or heat pulse 22 generated by the housing structure 12 or the localized heating and/or heat pulse 22 generated by a portion of the inertial detection sensor 24.

IR radiation 20 and target fluid F_TIs through the ambient atmosphere F_EOf (2) a target fluid F_TAbsorption of IR radiation 20 and wherein a reference fluid F is passed_RAbsorption of the IR radiation 20 results in a reference fluid F_RAnd due to temperature change Δ T ofThis results in a pressure change Δ P in the chamber 14 which affects the mechanical impulse 22 in the shell structure 12.

In other words, the fluid sensor or detector 10 is filled with a reference gas (fluid) F_RAnd the propagation path P from the IR emitter 18 to the detector 10 is the measurement path. Absence of target gas (fluid) F in the absorption path_TWill sense the maximum amplitude of the mechanical pulse 22 in the housing structure 12, since the maximum amplitude of the IR radiation 20 can enter the chamber 14. If the target gas F_TThe absorption in this path increases as does the ambient concentration, with the result that the detector 10 will receive less of the increase in temperature T due to the lack of energy for absorption. In order to provide as precise an operation of the detector 10 as possible during lifetime, the passage hole or perforation 16 is removed and the cavity 14 is hermetically sealed.

According to an embodiment based on a first (═ primary) measurement effect, the reference fluid composition F_RIs a target fluid F_TI.e. the sealed chamber 14 is filled with the target fluid F_T。

In addition, in the ambient atmosphere F_EOf the IR radiation 20 with the target fluid F_TMay cause a temperature change at of at least a part 12-3 of the housing structure 12 or a part of the inertial detection sensor 24, which temperature change at affects the mechanical impulse 22 in the housing structure 12 or the mechanical impulse 22 in the inertial detection sensor 24, respectively. The radiation receiving area 12-3 is disposed inside the chamber 14 and in or on the cover 12-1, in or on the substrate 12-2, and/or in or on the inertial detection sensor 24 12-2. Local heating of the radiation receiving section 12-3 of the housing structure 12 or of the radiation receiving section 12-3 of the inertial detection sensor 24 and from the ambient atmosphere F_EOf (2) a target fluid F_TThe absorption of IR radiation 20 is inversely proportional. Heating of the radiation receiving section 12-3 by the IR radiation 20 reduces the heating in the ambient atmosphere F_EOf (2) a target fluid F_TIR radiation absorption amount of (a).

According to an embodiment based on a second (secondary) measurement effect, the reference fluid component F_RIs a streamA bulk component that has no or very low absorption of the IR radiation 20 entering the chamber 14.

According to the embodiment of the fluid sensor 10 described with respect to fig. 1 to 5, the (radiation receiving) portion 12-3 of the housing structure 12 affects the mechanical pulses 22 in the housing structure 12, or additionally or alternatively, the (radiation receiving) portion 12-3 of the inertial detection sensor 24 affects the mechanical pulses 22 in the inertial detection sensor 24. Thus, the above-described evaluations relating to fig. 1-5 regarding the structure and function of the fluid sensor 10 are equally applicable to the fluid sensor 10 as described below, i.e., the following implementations of the fluid sensor 10 are compatible with the (optional) functions of the other implementations described above.

Thus, according to an embodiment, the fluid sensor 10 may include a housing structure 12 forming the chamber 14, an inertial detection sensor 24, wherein a portion of the inertial detection sensor 24 forms the radiation receiving section 12-3 and the IR emitter 18. An IR emitter 18 is optionally coupled to the housing structure (12) and configured for emitting IR radiation 20 in the chamber 14, wherein the IR radiation 20 has a central wavelength λ₀For providing IR radiation 20 with the target fluid F_TThe interaction of (a). The interaction results in a temperature change Δ T in the radiation receiving section 12-3 of the inertial detection sensor 24. The temperature change Δ T in the radiation receiving section 12-3 affects the mechanical pulse 22 in the inertial detection sensor 24, wherein the inertial detection sensor 24 is arranged for sensing the mechanical pulse.

According to an embodiment, the IR radiation 20 is directed towards the target fluid F_TIs the absorption of the IR radiation 20 by the target fluid, which results in a temperature change in the radiation receiving section 12-3 of the inertial detection sensor 24, wherein the heating of the radiation receiving section 12-3 of the inertial detection sensor 24 and the passing of the target fluid F_TThe absorption of IR radiation 20 is inversely proportional.

According to an embodiment, the inertial detection sensor 24 comprises an accelerometer configured to provide the detector output signal S based on the amplitude of the mechanical pulse 20 in the radiation receiving section 12-3 of the inertial detection sensor 24_OUT1。

Additional embodiments and aspects are described that may be used alone or in combination with the features and functions described herein.

According to an embodiment, a fluid sensor includes: a housing structure forming a chamber for a target fluid composition; an IR emitter configured to emit IR radiation in the chamber, wherein the IR radiation has a central wavelength for providing an interaction of the IR radiation with a target fluid, the interaction resulting in a temperature change in the chamber or in the housing structure, the temperature change affecting a mechanical pulse in the housing structure; and an inertial detection sensor mechanically coupled to the housing structure for sensing mechanical impulses in the housing structure.

According to an embodiment, the interaction of the IR radiation with the target fluid is an absorption of the IR radiation by the target fluid, and wherein the absorption of the IR radiation by the target fluid causes a temperature change in the target fluid and thus a pressure change in the chamber, which pressure change affects the mechanical impulse in the housing structure.

According to an embodiment, the interaction of the IR radiation with the target fluid is an absorption of the IR radiation by the target fluid, the absorption resulting in a temperature change or a heat pulse in the housing structure, wherein the heating of the housing structure is inversely proportional to the absorption of the IR radiation by the target fluid.

According to an embodiment, heating of the housing structure by IR radiation reduces the amount of IR radiation absorption by the target fluid.

According to an embodiment, the housing structure comprises a mechanical pulse amplification structure for providing a mechanical amplification of the mechanical pulse in the housing structure, wherein the amplification of the mechanical pulse depends on a temperature change of the housing structure or a temperature change of a region of the housing structure, the region of the housing structure (12) being thermally coupled to the mechanical vibration amplification structure.

According to an embodiment, the inertial detection sensor comprises an accelerometer configured to provide a detector output signal based on an amplitude of a mechanical pulse of the housing structure received by the inertial detection sensor mechanically coupled to the housing structure.

According to an embodiment, the accelerometer comprises a piezoelectric sensor structure and/or a capacitive sensor structure for sensing mechanical pulses in the housing structure.

According to an embodiment, the inertial detection sensor comprises a suspended mechanical sensor structure having a mechanical resonance frequency in the range between 5Hz and 25kHz or in the range between 5Hz and 100 Hz.

According to an embodiment, the housing structure comprises a cover structure mechanically coupled to the base plate or the base element, wherein the inertial detection sensor is mechanically coupled to the cover structure or the base plate.

According to an embodiment, the fluid sensor further comprises a plurality of inertial detection sensors mechanically coupled to the housing structure for sensing mechanical pulses in the housing structure.

According to an embodiment, at least one of the plurality of inertial detection sensors is arranged at a housing structure within the chamber or at least one of the plurality of inertial detection sensors is arranged at a housing structure outside the chamber.

According to an embodiment, at least one of the plurality of inertial detection sensors is arranged at a housing structure within the chamber and at least one of the plurality of inertial detection sensors is arranged at a housing structure outside the chamber.

According to an embodiment, the IR emitter is arranged in the chamber or optically coupled to the chamber.

According to an embodiment, the IR emitter comprises an LED element, a laser element and/or a heat emitter element.

According to an embodiment, the IR emitter comprises an infrared source and a wavelength selective structure for providing IR radiation pulses having a central wavelength.

According to an embodiment, the wavelength selective structure is arranged for filtering broadband IR radiation emitted by the thermal emitter and for emitting narrowband IR radiation into the chamber.

According to an embodiment, the chamber in the housing structure is arranged for providing an optical interaction path for IR radiation for interaction of the target fluid.

According to an embodiment, the fluid sensor further comprises a differential pressure sensor arranged in the chamber of the housing structure to provide a further detector output signal based on a pressure change generated in the chamber of the housing structure by the IR radiation.

According to an embodiment, the fluid sensor further comprises a processing circuit or controller for providing time-varying and pulsed excitation signals to the IR emitter and for reading out the inertial detection sensor, thereby providing information about the concentration of the target fluid component in the ambient fluid.

According to an embodiment, the housing structure comprises a fluid channel leading to the chamber for an ambient fluid comprising the target fluid component.

According to an embodiment, the chamber in the housing structure is hermetically closed and comprises the target fluid composition.

According to an embodiment, a part of the cover and/or the substrate and/or a part of the inertial detection sensor forms a radiation receiving section arranged such that a temperature change Δ Τ in the radiation receiving section affects the mechanical pulse.

According to an embodiment, a fluid sensor comprises: a housing structure forming a chamber; an inertial detection sensor, wherein a portion of the inertial detection sensor forms a radiation receiving section; and an IR emitter optically coupled to the housing structure and configured to emit IR radiation in the chamber, wherein the IR radiation has a central wavelength λ₀For providing an interaction of the IR radiation with the target fluid, which interaction results in a temperature change in a radiation receiving section of the inertial detection sensor, which temperature change affects the mechanical pulses in the inertial detection sensor, wherein the inertial detection sensor is arranged for sensing the mechanical pulses.

According to an embodiment, the IR radiation interacts with a target fluid F_TIs the absorption of IR radiation by the target fluid, which absorption results in a temperature change in the radiation receiving section of the inertial detection sensor, wherein the heating of the radiation receiving section of the inertial detection sensor and the IR radiation by the target fluidThe absorption is inversely proportional.

According to an embodiment, the inertial detection sensor comprises an accelerometer configured to provide the detector output signal based on an amplitude of the mechanical pulse in the radiation receiving section of the inertial detection sensor.

Although some aspects are described as features in the context of an apparatus, it will be apparent that such description may also be regarded as a description of corresponding features of a method. Although some aspects have been described as features in the context of a method, it will be apparent that such description may also be regarded as a description of corresponding features with respect to the function of the apparatus.

In the foregoing detailed description, it can be seen that various features are grouped together in the examples for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed examples require more features than are expressly recited in each claim. Rather, as the following claims reflect, subject matter may lie in less than all features of a single disclosed example. Thus the following claims are hereby incorporated into the detailed description, with each claim standing on its own as a separate example. Although each claim may stand alone as its own separate example, it should be noted that although a dependent claim may refer in the claims to a particular combination with one or more other claims, other examples may also include a combination of the dependent claim with the subject matter of each other dependent claim, or a combination of each feature with other dependent claims or independent claims. Such combinations are presented herein unless indicated otherwise. Furthermore, it is intended that features of a claim are also included in any other independent claim, even if this claim is not directly dependent on the independent claim.

Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present embodiments. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that the embodiments be limited only by the claims and the equivalents thereof.