Environmental sensor assembly

Abstract

An environmental sensor assembly comprising: a package; and an environmental sensor disposed in the package, the environmental sensor including a sensing region and a reference region. Wherein the package comprises one or more entrances arranged symmetrically with respect to the sensing region and the reference region; and wherein the sensing region is in fluid communication with an external environment through the one or more inlets. A method of manufacturing an environmental sensor assembly is also described.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an environmental sensor assembly comprising an encapsulated environmental sensor, such as a fluid sensor (e.g. a gas sensor and / or including a humidity sensor) or a particulate sensor. BACKGROUND

[0002] Environmental sensors, such as fluid sensors or gas sensors, are widely used in many applications due to their low cost, small size, ability to measure a large number of fluids (e.g. gases) and a large range of concentrations.

[0003] An environmental sensor can include a sensing region and a reference region, as well as any circuitry to ensure that the sensor functions properly in the chosen application.

[0004] A sensor including a reference region can provide accurate results under a variety of sensing conditions. On the other hand, the addition of a reference region also increases the overall size of the device.

[0005] Typically, an environmental sensor is placed within an encapsulation, which can protect the environmental sensor, as well as any other electronic components or connections, from the external environment, including any flow that can affect the accuracy of the environmental sensor readings. The combination of the environmental sensor and the encapsulation can be referred to as an environmental sensor assembly.

[0006] One stringent requirement for any environmental sensor is that it has a fast response time. For example, a sensor should detect a gas leak as soon as possible so that the system can respond and prevent potentially devastating consequences, such as an explosion, poisoning or a major malfunction.

[0007] However, the response time of any system depends only partially on the type and technology of the sensor used in the system. The reaction time also depends to a large extent on the time it takes for the gas (or other fluid) to reach the sensing region of the sensor. The sensor is typically located in an encapsulation and / or housing. The speed at which gas molecules reach the sensor housing or encapsulation can be increased by providing a fan, a blower or by utilizing convection and buoyancy, among other ways. However, once the gas molecules reach the aperture in the sensor housing or encapsulation, the time it takes for these molecules to reach the sensing region of the sensor depends on the diffusion of the gas.

[0008] For a sensor assembly having an environmental sensor that includes a sensing region and a reference region, it is desirable that the sensing region and the reference region are in the same thermal environment and / or interact with each other, which requires careful design of the encapsulation.

[0009] To facilitate integration into various systems and various applications, the sensor assembly preferably provides a low footprint standalone device that can be integrated into space-constrained applications.

[0010] EP2952886B1 relates to a method of manufacturing a gas sensor package. US8916408B2 relates to a preformed package based on a lead frame. US9708174B2 relates to a process of manufacturing a packaged device. SUMMARY

[0011] The present disclosure relates to an environmental sensor assembly comprising a package and an environmental sensor disposed in the package, which can solve one or more of the above-mentioned problems.

[0012] The environmental sensor comprises a sensing region (also referred to as a sensing portion) and a reference region (also referred to as a reference portion). The sensor assembly of the present invention provides fast and accurate sensing (e.g. of a fluid such as a gas) by providing a short diffusion path for target (e.g. gas) molecules to diffuse from outside the package inlet to the sensing region, and by reducing any possible thermal imbalance between the sensing region and the reference region. Furthermore, the present disclosure also provides a standalone and compact sensor assembly that is easy to integrate into various systems and suitable for various applications.

[0013] The package can protect the sensor from unwanted contamination or interference while ensuring that the sensor effectively interacts with the environment to operate reliably.

[0014] Aspects and preferred features are set out in the appended claims.

[0015] Described herein is an environmental sensor assembly comprising a package and an environmental sensor disposed in the package. The environmental sensor comprises a sensing region and a reference region. The package comprises one or more inlets that are symmetrically arranged with respect to the sensing region and the reference region. The sensing region is in fluid communication with an external environment through the one or more inlets.

[0016] Also described herein is a method of manufacturing an environmental sensor assembly, the method comprising disposing an environmental sensor in a package, the environmental sensor comprising a sensing region and a reference region, and forming one or more inlets in the package. The one or more inlets are symmetrically arranged with respect to the sensing region and the reference region such that the sensing region is in fluid communication with an external environment through the one or more inlets.

[0017] It can be appreciated that the sensing region refers to a place where a target fluid (e.g. a gas) interacts with the sensor to produce a sensor reading. The reference region can be fluidically isolated from the external environment.

[0018] Ideally, the sensing region and the reference region are under the same environmental conditions (e.g., the same external temperature). This way, when the differential reading of the sensor is collected, the effect of the environmental conditions is reduced or eliminated. This results in a more accurate sensor reading and improves the sensitivity of the environmental sensor. The reference region can not be in contact with the target fluid. In preferred embodiments, the sensing region and the reference region are identical.

[0019] The package protects the environmental sensor from the external environment, particularly from any foreign matter, dust, and / or any flow that can affect the accuracy of the sensor reading. Thus, the package provides the sensor with a degree of isolation from the external environment. On the other hand, the sensor needs to be exposed to the external environment to provide a meaningful reading, and the package enables such exposure by fluidly communicating the sensor with the external environment through one or more inlets (e.g., holes). Ideally, the package allows the sensing region and the reference region to be affected by the external environment in as close a manner as possible.

[0020] The symmetrical arrangement of the one or more inlets of the package relative to the sensing region and the reference region of the environmental sensor enables a substantially uniform thermal interaction between the sensing region and the reference region and the external environment. This can precisely reduce or eliminate the effect of external effects (e.g., changes in the external temperature) on the reading of the environmental sensor.

[0021] The package can include a package substrate and / or a cover for the environmental sensor. The environmental sensor can be located on a surface of the package substrate.

[0022] In certain examples, the environmental sensor includes a sensor substrate. The sensing region can include a sensing extent of the sensor substrate, and the reference region can include a reference extent of the sensor substrate. The sensor substrate can include a first major surface facing the package substrate and a second major surface opposite thereto. The cover can be disposed at least partially opposite the second major surface of the sensor substrate. The sensing extent and the reference extent can be disposed on the second major surface of the sensor substrate.

[0023] The package can have a single inlet.

[0024] The package can include a plurality of inlets.

[0025] The package can have an inlet opposite the sensing region and an inlet opposite the reference region.

[0026] The package can include one or more sidewalls, e.g., vertical walls, between the package substrate and the cover.

[0027] The one or more sidewalls can be integral with the cover.

[0028] The one or more sidewalls can be integral with the package substrate.

[0029] The package can be cuboid shaped or any other suitable shape.

[0030] The package can be made of any suitable material, such as a polymer, ceramic, metal, composite material, etc.

[0031] The package substrate can be made of a lead frame, a printed circuit board (PCB) and / or plastic.

[0032] The package can have an inner wall for fluidically isolating the reference region from the rest of the package and from the external environment. Preferably, the inner wall can comprise a material with high thermal conductivity so that the thermal interaction between the reference region and the external environment can be as close as possible to the thermal interaction between the sensing region and the external environment.

[0033] In some examples, the inner wall can not be provided and the reference region can be fluidically isolated from the external environment because a suitable coating or isolating material does not allow the target fluid to interact with the reference region.

[0034] For facilitating the manufacturing of the environmental sensor, the sensing region and the reference region can be provided on the second main surface of the gas sensor substrate.

[0035] The one or more inlets can be at least partially provided on the lid so as to be at least partially opposite to the second main surface of the sensor substrate. In examples where the sensing region and the reference region are provided on the second main surface of the sensor substrate, this can bring the sensing region in close contact with the external environment, thus providing a short diffusion path for the target molecules to quickly reach the sensing region and thus quickly obtain a sensor reading.

[0036] The one or more inlets can be at least partially provided at one or more vertical or lateral walls so as to not overlap with the second main surface of the sensor substrate. This can provide a higher level of protection for the sensing region (and / or sensing area) from any external substances, dust and / or air flow; on the other hand, this can lengthen the diffusion path from the one or more inlets to the sensing region, thus lengthening the time of output of the sensing reading.

[0037] The environmental sensor assembly can comprise a lid defining a reference chamber, the reference region comprising the reference chamber so that the reference region is fluidically isolated from the one or more inlets (i.e. of the package). Preferably, the lid comprises a material with high thermal conductivity (such as silicon or metal) so that the thermal interaction between the reference region and the external environment can be as close as possible to the thermal interaction between the sensing region and the external environment.

[0038] The cover can define two separate chambers: a sensing chamber (which can enclose a sensing range) and a reference chamber (which can enclose a reference range). The sensing region comprises the sensing chamber and the reference region comprises the reference chamber. The sensing chamber can comprise one or more apertures such that the sensing region is in fluid communication with one or more inlets (i.e. of the package). The reference chamber can be arranged to seal the reference region from the package.

[0039] The sensing chamber and the reference chamber can have the same shape and / or size.

[0040] The package can have a single inlet opposite the central region of the cover, e.g. opposite the central region of the cover’s axis of symmetry. Alternatively, the package can have a plurality of inlets arranged symmetrically with respect to the cover’s axis of symmetry, e.g. in a symmetrical pattern about the same axis or centre of symmetry of the cover.

[0041] In some embodiments, the package can have one set of one or more inlets facing the sensing region and one set of one or more inlets facing the reference region, the one or more inlets of each set being arranged symmetrically with respect to the respective sensing region or reference region. Such an arrangement can allow for the rapid filling of the interior space of the package with a fluid (e.g. a gas) without affecting the first sensing region, as the fluid can diffuse through the apertures in the cover rather than flowing.

[0042] The reference region (which can comprise the reference chamber) can be in a vacuum state (e.g. at or below 0.1 kPa), or it can be filled with a fluid (e.g. a gas) or a composition and pressure-controllable gas mixture. For example, the reference chamber can be filled with air or nitrogen at atmospheric pressure (about 100 kPa).

[0043] Preferably, the one or more apertures of the sensing chamber (i.e. in the cover) are laterally displaced with respect to the one or more inlets of the package, e.g. the one or more apertures can not overlap the one or more inlets of the package. This can avoid the formation of a direct or straight path from the external atmosphere to the sensing region, thereby providing a higher level of protection for the sensing region, in particular the sensing range, from the external environment.

[0044] In some embodiments, the one or more inlets and / or the one or more apertures can be equipped with a filter. In some cases, the inlet equipped with a filter can overlap the one or more apertures. In some embodiments, the one or more apertures equipped with a filter can overlap the inlet.

[0045] The sensing chamber can have an aperture in the lid. The aperture can be as large as possible to allow a large number of target fluid (e.g., gas) molecules to diffuse to the sensing region per unit time, but not so large that the sensing region is not properly protected from the external environment. Preferably, the sensing chamber can have a plurality of apertures of relatively small size to ensure good protection of the sensing region and to ensure diffusion of target fluid molecules to the sensing region per unit time.

[0046] In some embodiments, the environmental sensor includes a substrate including a sensing cavity in a sensing region and a reference cavity in a reference region; a dielectric layer disposed on the substrate, wherein the sensing cavity defines a sensing membrane in the dielectric layer and the reference cavity defines a reference membrane in the dielectric layer; and a first heating element on or within the sensing membrane and a second heating element on or within the reference membrane.

[0047] The sensor substrate with the dielectric layer can also be defined as a sensor chip. The surface of the sensor chip with the dielectric layer can be defined as a second surface of the sensor chip.

[0048] In some embodiments, the sensing membrane can correspond to a sensing range described herein, and the reference membrane can correspond to a reference range described herein. Ideally, when a lid having one or more apertures is provided in the sensing chamber, the one or more apertures are laterally offset (e.g., in a non-overlapping relationship) relative to the sensing membrane. This enables more effective protection of the sensing membrane. It can be appreciated that the sensing chamber and the reference chamber can enclose a larger area than the respective membranes or the respective sensing and reference regions.

[0049] The sensor substrate can be composed of any suitable material. For example, the sensor substrate can be composed of a semiconductor, such as silicon.

[0050] The dielectric layer can be composed of any suitable material, such as silicon oxide, silicon nitride, aluminum oxide, or a combination of these materials.

[0051] The heating elements can include platinum, tungsten, titanium, single-crystal silicon, polycrystalline silicon, and / or other suitable materials. The type, shape, and material of the heating elements are not limited, and any heating element known in the art can be used to implement the sensors described herein.

[0052] In some embodiments, the package can include a first portion having a first thickness in a direction perpendicular to one surface of the package and toward the sensor, and a second portion having a second thickness in the direction perpendicular to the surface of the package and toward the sensor, wherein the first thickness is different from the second thickness. For example, the structure of the package can at least partially match the shape of the sensor to reduce or minimize the internal dead volume of the package. This helps to improve the response speed of the sensor.

[0053] Portions of different thicknesses can be provided on one or more of the sidewalls and / or the lid.

[0054] In some embodiments, the thickest portion of one or more sidewalls can be immediately adjacent to the sensor, so as to at least partially have the same shape as the volume occupied by the sensor, and be separated from the sensor by only the minimum offset or gap needed to manufacture and position the sensor. In other words, a portion of the sidewall can follow a portion of the perimeter of the sensor.

[0055] The distance between the environmental sensor and the wall or walls closest to the environmental sensor can be less than 100 microns. More preferably, the distance between the environmental sensor and the wall or walls can be less than 50 microns.

[0056] In some cases, the surface of the lid facing the sensor can at least partially have a shape that matches the shape of the sensor. For example, the portion of the lid facing the sensor can have a different thickness than the portion of the lid not facing the sensor, for example, facing an area of the package with connection pads or other features, or an empty area of the package.

[0057] In one embodiment, the distance between the lid and the second surface of the sensor chip (or the outer surface of the lid, if any) can be 50 microns.

[0058] It can be appreciated that the size and number of inlets, and the thickness of the package with one or more inlets (which in turn defines the size of the one or more inlets in the direction through the package) can be optimized so that the internal volume of the package is conveniently reduced, and the diffusion of target fluid molecules through the inlets is not too limited.

[0059] For example, the thickness of a portion of the package containing the inlets can be less than the thickness of a portion of the package removed from the inlets.

[0060] The environmental sensor can be a thermal conductivity sensor (e.g., a thermal conductivity gas sensor), in which the sensor responds to changes in the thermal conductivity of its surrounding fluid (e.g., gas) due to changes in the composition of the fluid. For this type of sensor, it is preferred that the reference range be isolated from the external environment, while the sensing range be exposed to the environment.

[0061] The environmental sensor can be a catalytic sensor (e.g., a catalytic gas sensor) that includes a heating element and a catalyst in the sensing range, where at high temperatures the catalyst catalyzes combustion of a target fluid (e.g., a gas), resulting in an increase in temperature that can be measured by the heating element or a separate temperature sensor. In certain examples, both the sensing range and the reference range can contain a catalyst, and the reference range can be isolated from the external environment, while the sensing range can be exposed to the external environment. In other examples, both the sensing range and the reference range can be exposed to the external environment, but the reference range can not contain a catalyst, or the reference range can contain a catalyst that is covered by some other material to prevent interaction between the catalyst and the surrounding fluid.

[0062] The environmental sensor can be a resistive or capacitive sensor that includes a heating element and a sensing material in the sensing range, which changes in resistance or capacitance when a target fluid (e.g., a gas) is present. In certain examples, both the reference range and the sensing range can use the same sensing material, and the reference range can be isolated from the external environment. In other examples, neither of the two ranges can be isolated from the external environment. In this case, the reference range can not have the sensing material provided, or the sensing material can be coated to prevent interaction between the sensing material and the surrounding fluid.

[0063] The environmental sensor assembly can further include a circuit chip, such as an application-specific integrated circuit (ASIC), located within the package for controlling and operating the sensor.

[0064] The circuit chip can be located on a surface of the package substrate.

[0065] A thickness of the circuit chip in a direction perpendicular to the surface of the package substrate can be less than a thickness of the environmental sensor in the same direction.

[0066] In certain embodiments, the thickness of the circuit chip can be less than the thickness of the environmental sensor.

[0067] When the circuit chip is located inside the package, a structure of the package can at least partially match a shape of the environmental sensor and a shape of the circuit chip. In some embodiments, a surface of the lid facing the environmental sensor and the circuit chip has a shape that at least partially matches the shapes of the environmental sensor and the circuit chip. For example, a thickness of a portion of the lid facing the environmental sensor can be different (e.g., less) than a thickness of an area of the lid facing the circuit chip. BRIEF DESCRIPTION OF DRAWINGS

[0068] The present disclosure will now be described, by way of example only, with reference to the following drawings:

[0069] Figure 1 A cross-section of an example of an environmental sensor assembly according to the present disclosure;

[0070] Figure 2 Cross-section of an example of an environmental sensor assembly according to the present disclosure, including an environmental sensor having a cover;

[0071] Figure 3 Cross-section of an environmental sensor assembly according to the present disclosure, including an environmental sensor having a cover;

[0072] Figure 4 Cross-section of an environmental sensor assembly according to the present disclosure, including a sensing cavity and a reference cavity defined on a sensor substrate;

[0073] Figure 5A Top view of an environmental sensor according to the present disclosure;

[0074] Figure 5B : Figure 5A Side view of an environmental sensor shown;

[0075] Figure 6A Top view of an environmental sensor assembly according to the present disclosure, including an application specific integrated circuit (ASIC);

[0076] Figure 6B : Figure 6A Side view of an environmental sensor assembly shown;

[0077] Figure 7A Top view of an environmental sensor assembly according to the present disclosure, including an inlet elongated in one direction;

[0078] Figures 7B to 7D Top view of an environmental sensor assembly according to the present disclosure, including a plurality of inlets; and

[0079] Figure 8 Example of a method of manufacturing an environmental sensor assembly according to the present disclosure. DETAILED DESCRIPTION

[0080] Figure 1 A cross-section of an example of an environmental sensor assembly 10 according to the present disclosure is shown.

[0081] The environmental sensor assembly 10 comprises a package 100 and an environmental sensor 200 (also referred to herein as "sensor"). The package 100 has a lid 113, a package substrate 112, a sidewall 115 and an inlet 130. The sensor 200 comprises a sensor substrate 201, a bottom substrate 212 and a dielectric layer 203. The sensor substrate 201 has a first surface facing the package substrate and a second surface opposite thereto. The dielectric layer 203 is on the second surface of the sensor substrate. The sensor substrate 201 further has a sensing cavity 202 and a reference cavity 202a, the bottoms of which are closed by the bottom substrate 212. The sensing cavity 202 and the reference cavity 202a define a first membrane 204 (or sensing membrane) and a second membrane 204a (or reference membrane) in the dielectric layer, respectively, each membrane being provided with a respective heating element 205, 205a. Next to each membrane is a respective temperature sensor 206, 206a. It can be seen that the sensor 200 has two symmetrical regions, Figure 1 The right region is the sensing region, Figure 1 The left region is the reference region. The sensing range is the range on the first membrane 204 where the heating element 205 is present. The reference range is the range on the second membrane 204a where the heating element 205a is present.

[0082] The package 100 is further provided with an inner wall 131 that isolates the reference region from the external environmental fluid, while the sensing region is in communication with the external environmental fluid through the inlet 130. The sensor 200 is operated and controlled by a controller or readout circuit (not shown). In this case, the heating element 205 acts as a heating and sensing element that interacts with the target gas to determine the sensor output. The sensor output can be based on a differential signal obtained from the signal returned using the heating element 205 and the signal returned by the heating element 205a, which is not exposed to the target gas. The heating elements 205 and 205a are otherwise in the same or as close as possible environmental conditions. In some cases, the membranes 204 and 204a can be provided with separate sensing elements (not shown) in thermal contact with the respective heating elements 205 and 205a. The temperature sensors 206 and 206a are arranged outside the membranes 204 and 204a for measuring the environmental temperature of the sensor, which can be affected by the external temperature, i.e. the environmental temperature outside the sensor assembly 10.

[0083] The inlet 130 is positioned symmetrically to the sensing region and the reference region. The package 100 can have multiple inlets 130 as long as the inlets are symmetric to the sensing region and the reference region, such that both regions experience the same or as close as possible environmental conditions, e.g. external temperature variations.

[0084] Figure 1The image shows an inlet 130 provided on the cover of package 100, but this is by no means a limitation. One or more inlets 130 may additionally or alternatively be provided on one or more sidewalls 115, provided they are arranged symmetrically with respect to the sensing and reference areas. There is no overlap between the inlets 130 and the sensing or reference range.

[0085] Understandably, the inner wall 131 can be arranged in different ways, as long as it can isolate the reference area from the external environment from the fluid.

[0086] Figure 2 A cross-section of an example of an environmental sensor assembly 30 according to this disclosure is shown. Figure 2 The environmental sensor component 300 in the environmental sensor assembly 30 and the environmental sensor 300 Figure 1 The environmental sensor 200 is similar to that in the other two systems, except for the sensing range and reference range. Figure 2 The sensing range and reference range of the ambient environment sensor 300 are further provided with a catalytic layer or an oxide layer 305, 305a, respectively. In this case, the interaction between the sensor and the target fluid is achieved through the interaction between the target fluid and layer 305. Layer 305a is covered by a coating 325a, which prevents layer 305a from interacting with the external environment. In this example, Figure 1 The inner wall 131, which prevents the interaction between the layer 305a and the external environment, can be omitted because the reference area will be fluidly isolated from the external environment by the coating 325a. Furthermore, although the bottom substrate 212 is shown, it is not necessary in this configuration.

[0087] Figure 3 A cross-section of another example of the environmental sensor assembly 40 according to this disclosure is shown. Figure 3 The environmental sensor assembly 40 includes an environmental sensor 400 similar to the environmental sensor 200. Figure 1 Compared to the environmental sensor 200, Figure 3 The environmental sensor 40 also includes a cover 407 on a second surface of the sensor substrate 201. The cover 407 defines a sensing chamber 409 and a reference chamber 409a. The reference chamber 409a isolates a reference region (including a reference range) from external environmental fluids. The sensing chamber 409 has an aperture 408 that fluidly connects the sensing region (including the sensing range) to the internal space of the package 100, and consequently to the external environment. In this embodiment, the inlet 130 and the aperture 408 are non-overlapping.

[0088] Figure 4 This displays an environmental sensor component 40 ( Figure 3 A cross-section of a similar environmental sensor component 50. Figure 4An environmental sensor 500 is shown, which does not include a bottom substrate because the sensing cavity 502 and the reference cavity 502a are entirely defined by the sensor substrate 201.

[0089] Figure 5A A top view of an environmental sensor 600 is depicted, which is related to... Figure 3 or Figure 4 The environmental sensor is similar. Environmental sensor 600 is shown with cover 407, therefore the features below cover 407 are shown in dashed lines. Environmental sensor 600 is also shown without packaging. Figure 5B This is a side view of sensor 600. Heating elements 205 and 205a, and temperature sensors 206 and 206a are shown in microplate form, but are not limited to this. Elements 205, 205a, 206, and 206a are connected to pads 211 located on the second surface of sensor substrate 201 via circuitry 210. Cover 407 is narrower than sensor substrate 201, thus exposing pads 211. Membranes 204 and 204a are shown as circular, but any other shape may be chosen. In this example, cover 407 has multiple holes 608. Holes 608 do not overlap with the sensing area or membranes 204. It can be seen that the projection of the inlet 130 on cover 407 is depicted to show that the packaged inlet 130 is symmetrically arranged with respect to the sensing and reference areas of the sensor and does not overlap with the holes 608 of cover 407.

[0090] Figure 6A A top view of the environmental sensor assembly 70 of this disclosure is shown. The environmental sensor assembly 70 is shown together with the package 100, so the environmental sensor 700 and other components within the package are shown in dashed lines, including the sidewalls or the inner perimeter of the sidewalls of the package 100. For clarity, features of the environmental sensor located on the second surface of the sensor substrate are not shown.

[0091] from Figure 6A As can be seen, the environmental sensor assembly 70 has an inlet 130, which is symmetrically located on the cover 113 of the package 100 relative to the two regions of the environmental sensor 700. The environmental sensor 700 has a cover, the walls of which separate the sensing region from the reference region; two holes 608 are visible on the cover, located above the sensing region. The environmental sensor assembly 70 is also equipped with an application-specific integrated circuit (ASIC) 170 and an electrical connection region 175. In this example, the sidewalls of the package have portions of different thicknesses to match the shapes of the environmental sensor 700 and the ASIC 170. In this way, the internal dead volume of the package is minimized.

[0092] Figure 6BA side cross-section of the environmental sensor assembly 70 is shown. In this example, the area of the lid 113 opposite the environmental sensor 700 and the ASIC 170 has a different thickness to further reduce the dead volume inside the package and at least partially match the shape of the environmental sensor and the ASIC. In other words, the walls of the package can be described as defining a volume that at least partially matches the shape of the sensor and the ASIC.

[0093] Figures 7A to 7D Further examples of environmental sensor assemblies 70 are shown, including different arrangements of one or more inlets 130.

[0094] In Figure 7A , the package 100 has an inlet 130 elongated along one direction. The inlet is symmetric with respect to two regions of the environmental sensor 700.

[0095] In Figure 7B , the package 100 has multiple inlets 130 that are symmetric with respect to two regions of the environmental sensor 700.

[0096] Figure 7C And 7D the package in has two inlets 130 that are away from the center of the lid of the environmental sensor 700, but are still symmetric with respect to two regions of the environmental sensor 700.

[0097] Figure 8 An example of a method 800 of manufacturing an environmental sensor assembly according to the present disclosure is illustrated in the form of a schematic diagram. For example, the method 800 can be suitable for manufacturing any of the environmental sensor assemblies 10, 20, 30, 40, 50, 70 described and illustrated herein.

[0098] In step S802, the method 800 comprises placing an environmental sensor in a package, the environmental sensor comprising a sensing region and a reference region. It can be appreciated that the environmental sensor of the method 800 can be any suitable environmental sensor, such as any of the environmental sensors 200, 300, 400, 500, 600, 700 described and illustrated herein.

[0099] At step S804, the method 800 includes forming one or more inlets in the package that are symmetrically arranged relative to the sensing region and the reference region such that the sensing region is in fluid communication with the external environment through the one or more inlets. For example, the package of the method 800 can correspond to the package 100 described and illustrated herein. Forming the one or more inlets can include forming one or more openings in the package 100 by any suitable method, including drilling, or shaping the package 100 such that the package 100 has one or more openings. Forming the one or more inlets according to the method 800 can result in the package 100 containing one or more inlets 130 as described and illustrated herein.

[0100] It can be appreciated that the steps S802, S804 in the method 800 can be formed in any order. For example, the package can be received or produced, and the one or more inlets can be formed in the package before or after the environmental sensor is placed in the package. Alternatively, the package can be formed around the environmental sensor so that the environmental sensor is placed in the package after the package is formed.

[0101] Although the disclosure has been described in accordance with the above preferred embodiments, it is understood that these embodiments are merely illustrative and not limiting of the disclosure. Modifications and substitutions can be made by persons skilled in the art from the disclosure without deviating from the scope of the disclosure. Each feature disclosed or illustrated in this specification can be incorporated in any appropriate combination with any other feature disclosed or illustrated in this specification, and the disclosure is not limited to the combinations explicitly disclosed.

Claims

1. An environmental sensor assembly, comprising: Encapsulation; as well as An environmental sensor disposed within the package, the environmental sensor comprising a sensing area and a reference area; The encapsulation includes one or more entrances arranged symmetrically with respect to the sensing region and the reference region; and The sensing area is in fluid communication with the external environment through one or more inlets.

2. The environmental sensor assembly according to claim 1, wherein, The reference area is fluidly isolated from the external environment.

3. The environmental sensor assembly according to claim 1 or 2, wherein the reference region includes a reference range that is isolated from the external environmental fluid.

4. The environmental sensor assembly of claim 1 or 2, wherein the environmental sensor includes a cover defining a reference chamber, the reference area including the reference chamber such that the reference chamber is isolated from the one or more inlet fluids.

5. The environmental sensor assembly according to claim 4, wherein, One of the one or more inlets is opposite to the central region of the cover.

6. The environmental sensor assembly according to claim 4, wherein, The cover also defines a sensing chamber; The sensing area includes a sensing chamber; and The cover includes one or more holes, such that the sensing chamber is in fluid communication with the one or more inlets.

7. The environmental sensor assembly according to claim 6, wherein, The one or more holes are laterally offset relative to the one or more inlets.

8. The environmental sensor assembly according to claim 1 or 2, wherein, The environmental sensor includes: The sensing region includes a sensing cavity, and the reference region includes a reference cavity; A dielectric layer located on the substrate, wherein the sensing cavity defines a sensing film within the dielectric layer, and the reference cavity defines a reference film within the dielectric layer; and A first heating element located on or inside the sensing membrane, and a second heating element located on or inside the reference membrane.

9. The environmental sensor assembly according to claim 6, wherein, The environmental sensor includes: The sensing region includes a sensing cavity, and the reference region includes a reference cavity; A dielectric layer located on the substrate, wherein the sensing cavity defines a sensing film within the dielectric layer, and the reference cavity defines a reference film within the dielectric layer; and A first heating element located on or inside the sensing membrane, and a second heating element located on or inside the reference membrane; and The one or more holes are laterally offset relative to the sensing membrane.

10. The environmental sensor assembly of claim 1 or 2, comprising one or more inlets located on the sidewall of the package.

11. The environmental sensor assembly according to claim 1 or 2, wherein, The first of the one or more inlets is opposite to the sensing area, and the second of the one or more inlets is opposite to the reference area.

12. The environmental sensor assembly according to claim 1 or 2, further comprising a circuit chip disposed within the package.

13. The environmental sensor assembly of claim 12, wherein the package includes a package substrate, and the circuit chip is disposed on the surface of the package substrate.

14. The environmental sensor assembly according to claim 1 or 2, wherein, The package includes a first portion having a first thickness in a direction perpendicular to the surface of the package facing the environmental sensor; and a second portion having a second thickness in a direction perpendicular to the surface of the package facing the environmental sensor; wherein the first thickness and the second thickness are different.

15. The environmental sensor assembly of claim 1 or 2, wherein the package includes a cover; the surface of the cover facing the environmental sensor at least partially matches the shape of the environmental sensor.

16. The environmental sensor assembly of claim 12, wherein the package includes a cover facing the surfaces of the environmental sensor and the circuit chip, and at least partially matching the shape of the sensor and the shape of the circuit chip.

17. A method for manufacturing an environmental sensor assembly, the method comprising: An environmental sensor is placed in a package, which includes a sensing area and a reference area; as well as One or more inlets are formed in the package, which are arranged symmetrically with respect to the sensing region and the reference region, such that the sensing region is in fluid communication with the external environment through the one or more inlets.

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