Sensor packaging structure and ultrasonic gas flowmeter

Abstract

The invention provides a sensor packaging structure and an ultrasonic gas flowmeter. The ultrasonic gas flowmeter comprises a sensor structure and an acoustic structure. The sensor packaging structure comprises one or more thin film sensors, an interconnection layer and an interface layer. On one hand, the sensor structure and the acoustic structure are separately designed and are connected through the interface layer, so that the film sensor can be independently manufactured, and the production efficiency is improved. On the other hand, due to the double-layer stacked structure of the two PCB layers, the interconnection layer provides enough rigidity and support, circuit connection and mechanical interface functions are achieved together with the interface layer, and the structure is stable. And on the other hand, the total packaging thickness is smaller than the thickness of the acoustic structure, so that when the packaging structure is mounted at the inlet of the acoustic structure, the surface of the vibrating diaphragm of the thin film sensor does not contact or collide with the inner wall of the acoustic structure, sensor damage caused by mechanical stress is avoided, sound waves can enter an acoustic channel without hindrance, and the reliability of the sensor is improved. And normal operation of the film sensor is ensured.

Description

Technical Field

[0001] This application relates to the field of flow sensing technology, and more specifically, to a sensor packaging structure and an ultrasonic gas flow meter. Background Technology

[0002] The core components of an ultrasonic gas flow meter include the sensor structure and the acoustic structure. Existing sensors utilize bulk ceramic sensors made of materials such as lead zirconate titanate. These ceramic sensors are large and have a fixed output acoustic field angle. When designing pipelines for existing ultrasonic gas flow meters, to accommodate the bulk sensor structure, significant turbulence is typically generated at the sensor-pipe connection point, affecting the detection of small flow rates. Furthermore, the relatively fixed acoustic field angle of the bulk sensor limits the pipeline design due to the sensor's inherent characteristics, leading to mismatches between the pipeline and the connection structure. This weakens the acoustic gain and consequently affects the final measurement results. Summary of the Invention

[0003] The purpose of this application is to provide a sensor packaging structure and an ultrasonic gas flow meter, which enables the sensor structure to be manufactured, tested and replaced independently, improving production efficiency and equipment maintenance convenience; it improves the adaptability of the sensor structure, acoustic structure and pipeline, ensuring the stability of the sensor structure; it avoids sensor damage (such as diaphragm rupture) caused by mechanical stress during installation, and ensures that sound waves can enter the acoustic channel without obstruction, ensuring the normal operation and measurement accuracy of the sensor (ultrasonic gas flow meter).

[0004] This application provides a sensor packaging structure for use in an ultrasonic gas flow meter. The ultrasonic gas flow meter includes: a sensor structure and an acoustic structure; The sensor packaging structure includes: One or more thin-film sensors; An interconnect layer, electrically connected to the one or more thin-film sensors; and, An interface layer is disposed on the side of the interconnect layer away from the one or more thin-film sensors; one side of the interface layer is electrically connected to the interconnect layer, and the other side of the interface layer is mechanically connected to the inlet end of the acoustic structure; The thickness of the interconnect layer in the stacking direction is h1, where h1 ≥ 0.2 mm; The thickness of the interface layer in the stacking direction is h2, and the thickness of the acoustic structure in the stacking direction is H, where h1 + h2 < H.

[0005] In one embodiment, the one or more thin-film sensors include: a single-diaphragm thin-film sensor, a multi-diaphragm thin-film sensor, a plurality of single-diaphragm thin-film sensors, or any combination of the above three types of thin-film sensors.

[0006] In one embodiment, the one or more thin-film sensors include: a single-diaphragm thin-film sensor; The single-diaphragm thin-film sensor has a back cavity with a diameter of d. The interconnect layer has a first cavity that exposes the diaphragm cavity, and the first cavity extends for a length d1 in the X or Y direction. Where d1 = d ± 0.3 mm.

[0007] In one embodiment, the one or more thin-film sensors include: a multi-diaphragm thin-film sensor; The multi-diaphragm thin-film sensor has multiple back cavities, the total diameter of which is d; The interconnect layer has a first cavity that exposes the plurality of diaphragm cavities, and the first cavity extends for a length d1 in the X or Y direction. Where d1 = d ± 0.3 mm.

[0008] In one embodiment, the one or more thin-film sensors include: a plurality of single-diaphragm thin-film sensors; Each of the plurality of single-diaphragm thin-film sensors has a back cavity, and the diameter of each back cavity is d; The interconnect layer has a plurality of first cavities for exposing each of the diaphragm cavities in the plurality of single-diaphragm thin-film sensors, wherein the extension length of the first cavity in the X or Y direction is d11. Where, d11 = d ± 0.3 mm; The distance between the two farthest first cavities among the plurality of first cavities is d1.

[0009] In one embodiment, the interface layer has a second cavity that exposes the diaphragm cavity and the first cavity, and the extension length of the second cavity in the X or Y direction is d2; Where d2 = d1 ± 0.3 mm.

[0010] In one embodiment, the sensor packaging structure further includes: A housing is disposed on the side of the one or more thin-film sensors away from the interconnect layer, the housing covers the one or more thin-film sensors, and the housing has a contact surface with the interconnect layer.

[0011] In one embodiment, the sensor packaging structure further includes: An encapsulating adhesive is disposed on the side of the housing away from the one or more thin-film sensors. The encapsulating adhesive covers the housing and has contact surfaces with the housing, the interconnect layer, and the interface layer.

[0012] In one embodiment, the size of the entrance end of the acoustic structure in the XY plane matches the size of the interface layer in the XY plane.

[0013] In one embodiment, the one or more thin-film sensors include: a thin-film sensor array; The thin-film sensor array includes: a multi-diaphragm thin-film sensor, multiple single-diaphragm thin-film sensors, or a combination of a single-diaphragm thin-film sensor, a multi-diaphragm thin-film sensor, and multiple single-diaphragm thin-film sensors; The projection profile of the outlet end of the acoustic structure in the XY plane has a first distance in the X direction and a second distance in the Y direction. The magnitude of the final sound field angle output by the ultrasonic gas flow meter is related to (a) the symmetry of the arrangement of the thin-film sensor array in the XY plane; and (b) the ratio between the first distance and the second distance.

[0014] This application also provides an ultrasonic gas flow meter, including the sensor packaging structure described in any of the above claims.

[0015] This application has at least the following advantages or beneficial effects: 1. The sensor packaging structure provided in this application, on the one hand, separates the sensor structure from the acoustic structure and connects them through an interface layer, allowing the thin-film sensor to be manufactured, tested, and replaced independently, improving production efficiency and equipment maintenance convenience. On the other hand, it adopts a double-layer stacked structure of interconnect layer and interface layer. The interconnect layer provides sufficient rigidity and support to protect the thin-film sensor, while working with the interface layer to achieve circuit connection and mechanical interface functions, resulting in a stable structure. Furthermore, it is explicitly specified that the total packaging thickness is less than the thickness of the acoustic structure. This ensures that when the packaging structure is installed at the entrance of the acoustic structure, the diaphragm surface of the thin-film sensor will not contact or collide with the inner wall of the acoustic structure, thereby avoiding sensor damage (such as diaphragm rupture) caused by mechanical stress during installation, and ensuring that sound waves can enter the acoustic channel without obstruction, guaranteeing the normal operation and measurement accuracy of the sensor (ultrasonic gas flow meter).

[0016] 2. The sensor packaging structure provided in this application embodiment, for single-diaphragm thin-film sensors, achieves precise windowing of the interconnect layer by precisely defining the relationship between the first cavity size of the interconnect layer and the diameter of the cavity on the back of the sensor. The relationship setting of d1=d±0.3mm provides sufficient mechanical protection for the diaphragm, preventing the encapsulation material (such as glue) from flowing into the cavity and contaminating or obstructing the diaphragm; on the other hand, it ensures that the effective vibration area of ​​the diaphragm is fully exposed, maximizing the sound energy transmission and reception efficiency and optimizing acoustic performance.

[0017] 3. The sensor packaging structure provided in this application embodiment is for multi-diaphragm sensors (where multiple diaphragms work together). By defining the first cavity of the interconnect layer to cover the total range of all diaphragm cavities (d1=d±0.3mm), it ensures that the entire multi-diaphragm unit is completely exposed and protected as a whole sound source / receiving surface, thus guaranteeing that its designed acoustic characteristics (such as higher sensitivity or specific directivity) can be achieved.

[0018] 4. The sensor packaging structure provided in this application embodiment imposes dual constraints on distributed sensor arrays: first, the cavity size of each unit is matched to achieve unit-level protection; second, the relationship between the span of the entire array and the extension length of the second cavity in the interface layer in the X or Y direction is defined. This embodiment provides a precise hierarchical cavity packaging for multiple single-diaphragm sensor arrays, ensuring effective mechanical protection for each sensor unit while creating a uniform acoustic window with strictly aligned dimensions. This design not only solves the problem of reliable packaging of array sensors but also lays the physical foundation for ultrasonic flow meters to achieve advanced acoustic functions such as signal enhancement, beamforming, and directional control by forming a collaborative sensor array. Simultaneously, it significantly simplifies the production and assembly process and improves the module's versatility and reliability. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 A schematic diagram of a sensor packaging structure for an ultrasonic gas flow meter provided in one embodiment of this application; Figure 2 A schematic diagram of a sensor packaging structure for an ultrasonic gas flow meter provided in another embodiment of this application; Figure 3A schematic diagram of a sensor packaging structure for an ultrasonic gas flow meter, provided as another embodiment of this application; Figure 4a A schematic diagram of the acoustic structure of an ultrasonic gas flow meter provided in one embodiment of this application; Figure 4b A schematic diagram of the acoustic structure of an ultrasonic gas flow meter provided for another embodiment of this application; Figure 5a for Figure 4a The illustrated embodiment provides a top view of a sensor packaging structure for use in an ultrasonic gas flow meter; Figure 5b for Figure 4b The illustrated embodiment provides a top view of the sensor package structure of an ultrasonic gas flow meter; Figure 6 This is a schematic diagram of the structure of a reflective ultrasonic gas flow meter provided in one embodiment of this application; Figure 7 This is a schematic diagram of the structure of a through-beam ultrasonic gas flow meter provided in one embodiment of this application.

[0021] Explanation of reference numerals in the attached figures: Ultrasonic gas flow meter 100: Sensor structure 10: multi-diaphragm sensor 10a, single-diaphragm sensor 11; Acoustic structure 20: inlet end 21, outlet end 22, transition section 23; Fluid-stabilized structure 20a; Test body 30: First connector 31, second connector 32; Test pipe 40; Rectifier 50: rectifier body 51, rectifier channel 52; Sensor packaging structure 300: interconnect layer 301, housing 302, interface layer 303, encapsulating adhesive 304. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0024] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0025] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. In addition, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0026] Furthermore, terms such as "horizontal" and "vertical" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," not that the structure must be completely horizontal, but can be slightly tilted.

[0027] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0028] This application provides a sensor packaging structure 300 for use in an ultrasonic gas flow meter 100. The ultrasonic gas flow meter 100 includes a sensor structure 10 and an acoustic structure 20.

[0029] Please see Figures 1 to 3 The sensor package structure 300 includes: one or more thin-film sensors, an interconnect layer 301, and an interface layer 303. The one or more thin-film sensors can be implemented in various ways; for example, the sensor package structure 300 can be understood as including a single-diaphragm sensor 11 (e.g., Figure 1 As shown); this can be understood as the sensor packaging structure 300 including multiple single-diaphragm sensors 11 (such as... Figure 3 The diagram shows three single-diaphragm sensors 11); this can be understood as the sensor package structure 300 including a multi-diaphragm sensor 10a (e.g., Figure 2 The diagram includes a multi-diaphragm sensor 10a.

[0030] Both interconnect layer 301 and interface layer 303 can be configured as printed circuit boards (PCBs), such as interconnect layer 301 as the first PCB layer and interface layer 303 as the second PCB layer. Interconnect layer 301 is electrically connected to one or more thin-film sensors. Interface layer 303 is located on the side of interconnect layer 301 away from the one or more thin-film sensors. One side of interface layer 303 is electrically connected to interconnect layer 301, and the other side is mechanically connected to the entrance end 21 of acoustic structure 20. Interconnect layer 301 is directly electrically connected to the thin-film sensors, primarily responsible for the signal leads and electrical interconnection functions of the sensors. Interface layer 303 is located below the interconnect layer, with one side electrically connected to it and the other side mechanically connected to the acoustic structure, serving as a mechanical and electrical interface platform between the sensor module and the external acoustic structure.

[0031] The interconnect layer 301 has a thickness of h1 in the stacking direction, where h1 ≥ 0.2 mm. The interface layer 303 has a thickness of h2 in the stacking direction, and the acoustic structure 20 has a thickness of H in the stacking direction, where h1 + h2 < H. The stacking direction is as follows: Figure 4a and Figure 4b The Z direction is shown.

[0032] Both the interconnect layer 301 and the interface layer 303 have cavities that can act as acoustic waveguides to stabilize acoustic signals. The interconnect layer 301 is used for electrical connection with one or more thin-film sensors (MEMS). The interface layer 303 is used for mating with the acoustic structure 20 (acoustic horn).

[0033] The thickness h1 of the interconnect layer 301 in the stacking direction and the thickness h2 of the interface layer 303 in the stacking direction mainly affect the acoustic directivity of the ultrasonic gas flow meter 100. The thickness h2 of the interface layer 303 in the stacking direction is designed to stabilize the sound field. In this embodiment, two PCB layers are provided, wherein the thickness h1 of the interconnect layer 301 in the stacking direction is ≥0.2mm, but h1 cannot be too thick (h1 that is too thick does not meet mass production requirements). In some embodiments, h1 can be 0.25mm, 0.30mm, 0.34mm, 0.38mm, 0.41mm, 0.48mm, 0.53mm, 0.59mm, 0.64mm, 0.69mm, 0.71mm, 0.76mm, etc. (the size design of h1 is related to the thickness settings of the interface layer 303 and the acoustic structure 20).

[0034] The thickness h2 of the interface layer 303 in the stacking direction cannot be too thin, and the thickness h2 of the interface layer 303 in the stacking direction must match the horn opening of the acoustic structure 20. If the thickness h2 of the interface layer 303 in the stacking direction is too thin, the sound field will be disordered. In some embodiments, h2 can be 0.30mm, 0.34mm, 0.38mm, 0.41mm, 0.48mm, 0.53mm, 0.59mm, 0.64mm, 0.69mm, 0.71mm, 0.76mm, 0.83mm, 0.90mm, 1.05mm, 1.10mm, etc. (the size design of h2 is related to the thickness settings of the interconnect layer 301 and the acoustic structure 20).

[0035] In this embodiment, on the one hand, the sensor structure 10 and the acoustic structure 20 are designed separately and connected through the interface layer 303, so that the thin film sensor can be manufactured, tested and replaced independently, which improves production efficiency and equipment maintenance convenience.

[0036] On the other hand, a double-layer stacked structure of interconnect layer 301 and interface layer 303 is adopted. Interconnect layer 301 (thickness h1≥0.2mm) provides sufficient rigidity and support to protect the thin film sensor, while working with interface layer 303 to realize circuit connection and mechanical interface functions, resulting in a stable structure.

[0037] Furthermore, it is explicitly stipulated that the total encapsulation thickness (h1+h2) is less than the thickness (H) of the acoustic structure 20. This ensures that when the encapsulation structure is installed at the inlet of the acoustic structure 20, the diaphragm surface of the thin-film sensor will not come into contact with or collide with the inner wall of the acoustic structure 20, thereby avoiding sensor damage (such as diaphragm rupture) caused by mechanical stress during installation, and ensuring that sound waves can enter the acoustic channel without obstruction, thus guaranteeing the normal operation and measurement accuracy of the sensor (ultrasonic gas flow meter 100).

[0038] In one embodiment, one or more thin-film sensors include: a single-diaphragm sensor 11 (such as...) Figure 1 As shown), a multi-diaphragm sensor 10a (as shown) Figure 2 The diagram shows a multi-diaphragm sensor 10a and multiple single-diaphragm sensors 11 (e.g., Figure 3 The above includes three single-diaphragm sensors 11), or any combination of the above three types of thin-film sensors.

[0039] This embodiment clarifies the types of sensors (single diaphragm, multi diaphragm, array, and combination) that the sensor packaging structure 300 can be adapted to, greatly expanding the versatility of the sensor packaging structure 300. The sensor packaging structure 300 is a platform solution that can meet the needs of ultrasonic gas flow meter 100 products with different performance, cost, and functional requirements (such as directivity and sound pressure).

[0040] In one embodiment, such as Figure 1 As shown (a cross-sectional view of the sensor package structure 300 in the XZ plane, or a cross-sectional view in the YZ plane), one or more thin-film sensors include: a single-diaphragm sensor 11. The single-diaphragm sensor 11 has a back cavity with a diameter of d. The interconnect layer 301 has a first cavity that exposes the diaphragm cavity, and the first cavity has an extension length of d1 in the X or Y direction. Wherein, d1 = d ± 0.3 mm.

[0041] In this embodiment, for a single-diaphragm thin-film sensor, a precise window is achieved in the interconnect layer 301 by precisely defining the relationship between the first cavity size (d1) of the interconnect layer 301 and the diameter (d) of the cavity on the back of the sensor (d1=d±0.3mm). The d1=d±0.3mm relationship provides sufficient mechanical protection for the diaphragm, preventing encapsulation materials (such as adhesive) from flowing into the cavity and contaminating or obstructing the diaphragm; on the other hand, it ensures that the effective vibration area of ​​the diaphragm is fully exposed, maximizing the efficiency of sound energy transmission and reception, and optimizing acoustic performance.

[0042] In a first specific embodiment, the interface layer 303 has a second cavity that exposes the diaphragm cavity and the first cavity. The extension length of the second cavity in the X or Y direction is d2; where d2 = d1 ± 0.3 mm. In one specific embodiment, d = 0.6 mm; d1 can be set to 0.5 mm-0.7 mm; d2 can be set to 0.8 mm-1.0 mm. h1 ≥ 0.2 mm, h2 is not limited and is determined by the peripheral circuit. In one embodiment, h1 = 0.3 mm, the thickness H of the acoustic structure 20 is 1.2 mm, and h2 can be set to 0.55 mm.

[0043] In one embodiment, such as Figure 2 As shown (a cross-sectional view of the sensor package structure 300 in the XZ plane, or a cross-sectional view in the YZ plane), one or more thin-film sensors include: a multi-diaphragm sensor 10a. The multi-diaphragm sensor 10a has multiple back cavities, the total diameter of the multiple back cavities in the X or Y direction being d. The interconnect layer 301 has a first cavity that exposes the multiple diaphragm cavities, the first cavity having an extension length of d1 in the X or Y direction; where d1 = d ± 0.3 mm.

[0044] In this embodiment, the multi-diaphragm sensor 10a (whose multiple diaphragms work together) is designed to ensure that the entire multi-diaphragm unit is fully exposed and protected as a whole sound source / receiver surface by defining the first cavity of the interconnect layer 301 to cover the total range of all its diaphragm cavities (d1=d±0.3mm), thus ensuring that its designed acoustic characteristics (such as higher sensitivity or specific directivity) can be achieved.

[0045] In a second specific embodiment, the interface layer 303 has a second cavity that exposes the diaphragm cavity and the first cavity. The extension length of the second cavity in the X or Y direction is d2; where d2 = d1 ± 0.3 mm. In one specific embodiment, d = 0.5 mm; d1 can be set to 0.4 mm-0.6 mm; d2 can be set to 0.7 mm-0.9 mm. h1 ≥ 0.2 mm, h2 is not limited and is determined by the peripheral circuit. In one embodiment, h1 = 0.35 mm, the thickness H of the acoustic structure 20 is 1.2 mm, and h2 can be set to 0.55 mm.

[0046] In one embodiment, such as Figure 3 As shown (a cross-sectional view of the sensor package structure 300 in the XZ plane, or a cross-sectional view in the YZ plane), one or more thin-film sensors include: a plurality of single-diaphragm sensors 11. Each of the plurality of single-diaphragm sensors 11 has a back cavity, and the diameter of each back cavity is d. An interconnect layer 301 has a plurality of first cavities for exposing each diaphragm cavity of the plurality of single-diaphragm sensors 11, and the first cavity extends for a length of d11 in the X or Y direction, where d11 = d ± 0.3 mm. The distance between the two farthest first cavities is d1. An interface layer 303 has a second cavity that exposes the diaphragm cavity and the first cavity, and the second cavity extends for a length of d2 in the X or Y direction, where d2 = d1 ± 0.3 mm.

[0047] In this embodiment, for the distributed sensor array, dual constraints are imposed: first, the cavity size of each unit is matched (d11=d±0.3mm) to achieve unit-level protection; second, the relationship between the span (d1) of the entire array and the extension length (d2) of the second cavity in the interface layer 303 in the X or Y direction is defined (d2=d1±0.3mm). This embodiment provides a precise hierarchical cavity encapsulation (d11=d±0.3mm, d2=d1±0.3mm) for multiple single-diaphragm sensor arrays, ensuring effective mechanical protection for each sensor unit while creating a uniform acoustic window with strictly aligned dimensions. This design not only solves the problem of reliable encapsulation of array sensors but also lays the physical foundation for advanced acoustic functions such as signal enhancement, beamforming, and directional control in ultrasonic flow meters by forming a collaborative sensor array. Simultaneously, it significantly simplifies the production and assembly process and improves the module's versatility and reliability.

[0048] In a third specific embodiment, d = 0.55 mm; d11 can be set to 0.45 mm - 0.65 mm; d1 can be set to 2.5 mm - 2.8 mm (including the span of the entire array of three single-diaphragm sensors 11). d2 can be set to 2.4 mm - 2.9 mm. h1 ≥ 0.2 mm, h2 is not limited and is determined by the peripheral circuit. In one embodiment, h1 = 0.45 mm, the thickness H of the acoustic structure 20 is 1.3 mm, and h2 can be set to 0.65 mm.

[0049] In one embodiment, the interface layer 303 has a second cavity that exposes the diaphragm cavity and the first cavity, and the extension length of the second cavity in the X or Y direction is d2; wherein, d2 = d1 ± 0.3 mm.

[0050] In this embodiment, the cavity size (d2) of the interface layer 303 is further required to be precisely matched with the first cavity size (d1) (d2 = d1 ± 0.3 mm). This creates a precisely aligned acoustic tunnel from the diaphragm to the acoustic inlet along the sound wave propagation path. This design minimizes sound wave reflection, scattering, and eddy currents caused by cavity misalignment or abrupt changes in cross-section, significantly reducing ultrasonic signal transmission loss and improving signal-to-noise ratio and measurement stability.

[0051] In one embodiment, the sensor packaging structure 300 further includes a housing 302. The housing 302 is disposed on the side of one or more thin-film sensors away from the interconnect layer 301. The housing 302 covers one or more thin-film sensors and has a contact surface with the interconnect layer 301.

[0052] In this embodiment, a housing 302 structure is added to directly encapsulate one or more thin-film sensors. Its main effects are: to provide a primary physical barrier and environmental protection, preventing accidental contact, dust intrusion, and direct condensation of moisture on the sensors during installation; at the same time, the sealed cavity formed by the housing 302 and the interconnecting layer 301 provides an ideal space for subsequent possible potting processes, which helps to control the flow and curing form of the adhesive.

[0053] In one embodiment, the sensor encapsulation structure 300 further includes an encapsulating adhesive 304. The encapsulating adhesive 304 is disposed on the side of the housing 302 away from one or more thin-film sensors, the encapsulating adhesive 304 covers the housing 302, and the encapsulating adhesive 304 has contact surfaces with the housing 302, the interconnect layer 301, and the interface layer 303.

[0054] In this embodiment, an encapsulating adhesive 304 is added to the outside of the housing 302, achieving ultimate, integrated sealing and protection. The encapsulating adhesive 304 can effectively resist the effects of harsh industrial environments such as humidity, corrosive gases, oil stains, and long-term vibration, firmly bonding all internal components (one or more thin-film sensors, housing 302, interconnect layer 301, and interface layer 303) into a high-strength integrated module, greatly improving the long-term environmental reliability, mechanical strength, and airtightness of the sensor package.

[0055] In one embodiment, the fabrication steps of the sensor encapsulation structure 300 include: forming one or more thin-film sensors on an interconnect layer 301, and directly encapsulating the one or more thin-film sensors with a housing 302. An interface layer 303 is disposed on the surface of the interconnect layer 301 away from the one or more thin-film sensors. An encapsulating adhesive 304 is disposed on the side of the housing 302 away from the one or more thin-film sensors, the encapsulating adhesive 304 covering the housing 302, and the encapsulating adhesive 304 having contact surfaces with the housing 302, the interconnect layer 301, and the interface layer 303. The encapsulating adhesive 304 firmly bonds all internal components (one or more thin-film sensors, housing 302, interconnect layer 301, and interface layer 303) into a high-strength integral module to form the sensor encapsulation structure 300. The sensor encapsulation structure 300 is connected to the acoustic structure 20 to form an ultrasonic gas flow meter 100.

[0056] In one embodiment, see Figure 4a and Figure 4b The acoustic structure 20 includes an inlet end 21, an outlet end 22, and a transition section 23. The size of the inlet end 21 of the acoustic structure 20 in the XY plane matches the size of the interface layer 303 in the XY plane.

[0057] In this embodiment, the interface layer 303 and the inlet end 21 of the acoustic structure 20 are matched in planar dimensions, ensuring a tight fit and effective seal between the interface layer 303 and the acoustic structure 20 during mechanical docking, preventing leakage of the measured gas; at the same time, it ensures the precise alignment of the inlet end 21 of the acoustic structure 20, so that the sound waves emitted by one or more thin-film sensors can be coupled into the acoustic structure 20 (such as a measurement pipe or sound channel) with high efficiency and low distortion, thus optimizing the energy transfer efficiency.

[0058] In one embodiment, one or more thin-film sensors include a thin-film sensor array. The thin-film sensor array includes a multi-diaphragm sensor 10a, a plurality of single-diaphragm sensors 11, or a combination of a single-diaphragm sensor 11, a multi-diaphragm sensor 10a, and a plurality of single-diaphragm sensors 11. The projected profile of the outlet end 22 of the acoustic structure 20 in the XY plane has a first distance in the X direction and a second distance in the Y direction.

[0059] The final output sound field angle of the ultrasonic gas flow meter 100 is related to (a) the symmetry of the thin-film sensor array arrangement in the XY plane and (b) the ratio between the first distance and the second distance. That is, by coordinating the control of (a) the symmetry of the sensor array arrangement in the XY plane and (b) the ratio between the first distance L1 and the second distance L2, flexible adjustment of the final output sound field angle of the ultrasonic gas flow meter 100 can be achieved. This allows for greater miniaturization and flexibility, enabling more flexible adjustment of the sound field angle to adapt to different pipeline designs.

[0060] Specifically, for (a) the symmetry of the sensor array arrangement in the XY plane, it includes: symmetrical arrangement of the sensor array (the distance a between any two adjacent thin film sensors in the X-axis direction is equal to the distance b between any two adjacent thin film sensors in the Y-axis direction), and asymmetrical arrangement of the sensor array (the distance a between any two adjacent thin film sensors in the X-axis direction is not equal to the distance b between any two adjacent thin film sensors in the Y-axis direction).

[0061] Specifically, regarding (b) the ratio between the first distance L1 and the second distance L2, this includes: the ratio between the first distance L1 and the second distance L2 = 1:1, and the ratio between the first distance L1 and the second distance L2 ≠ 1:1. If the outlet end 22 of the acoustic horn is circular, then the ratio of the first distance L1 and the second distance L2 is 1:1; if the outlet end 22 of the acoustic horn is elliptical, then the ratio of the first distance L1 and the second distance L2 is not equal to 1:1. The ratio of the first distance L1 and the second distance L2 determines the difference in the aperture of the outlet end 22 of the acoustic horn in the X and Y directions, and is a structural parameter that controls the anisotropy of the beam divergence angle.

[0062] Specifically, the ultrasonic gas flow meter 100 can be divided into four categories: (1) The sensor array is symmetrically arranged, and the ratio between the first distance L1 and the second distance L2 is 1:1, forming an isotropic sound field. (2) The sensor array is asymmetrically arranged, and the ratio between the first distance L1 and the second distance L2 is not 1:1, forming an isotropic sound field. (3) The sensor array is symmetrically arranged, and the ratio between the first distance L1 and the second distance L2 is not 1:1, forming an anisotropic sound field. (4) The sensor array is asymmetrically arranged, and the ratio between the first distance L1 and the second distance L2 is not 1:1, forming an anisotropic sound field.

[0063] In this embodiment, the design extends from the physical structure of the sensor packaging structure 300 to the acoustic performance design of the ultrasonic gas flow meter 100. The final acoustic field characteristics of the ultrasonic gas flow meter 100 (affecting measurement range, accuracy, and sensitivity to flow) can be synergistically adjusted by optimizing the symmetry of the sensor array arrangement within the sensor packaging structure 300. That is, designers have greater design freedom, actively shaping an ideal acoustic field to meet the needs of specific application scenarios by designing the sensor packaging structure 300 to achieve (a) the symmetry of the thin-film sensor array arrangement in the XY plane; and (b) the ratio between the first and second distances in the projected profile of the outlet end 22 of the acoustic structure 20 in the XY plane.

[0064] like Figure 4a As shown, the entrance end 21 of the acoustic structure 20 is an ellipse with a major axis length of Ra and a minor axis length of Rb. Figure 5a for Figure 4a The illustrated embodiment provides a top view of the sensor package structure 300 of the ultrasonic gas flow meter 100. Figure 5a One or more thin-film sensors include nine single-diaphragm sensors arranged in a 3x3 grid. Figure 5a The distance 'a' between any two adjacent thin-film sensors in the X-axis direction is not equal to the distance 'b' between any two adjacent thin-film sensors in the Y-axis direction, and the sensor array is asymmetrically arranged. The interconnect layer 301 is electrically connected to one or more thin-film sensors. The structural dimensions of the interconnect layer 301 are set according to the structural dimensions of one or more thin-film sensors (e.g., ...). Figure 5a The sensor array is rectangular, and the interconnect layer 301 is also rectangular. One side of the interface layer 303 is electrically connected to the interconnect layer 301, and the other side of the interface layer 303 is mechanically connected to the entrance end 21 of the acoustic structure 20. The structural dimensions of the interface layer 303 are set according to the structural dimensions of the entrance end 21 of the acoustic structure 20. (e.g.) Figure 4aThe inlet end 21 of the acoustic structure 20 has an elliptical end face, such as... Figure 5a Interface layer 303 is also elliptical.

[0065] like Figure 4b As shown, the inlet end 21 of the acoustic structure 20 has a circular end face with a diameter of R. Figure 5b for Figure 4b The illustrated embodiment provides a top view of the sensor package structure 300 of the ultrasonic gas flow meter 100. Figure 5b One or more thin-film sensors include nine single-diaphragm sensors arranged in a 3x3 grid. Figure 5b The spacing 'a' between any two adjacent thin-film sensors along the X-axis is equal to the spacing 'b' between any two adjacent thin-film sensors along the Y-axis, and the sensor array is symmetrically arranged. The interconnect layer 301 is electrically connected to one or more thin-film sensors. The structural dimensions of the interconnect layer 301 are set according to the structural dimensions of one or more thin-film sensors (e.g., ...). Figure 5b The sensor array is square, and the interconnect layer 301 is also square. One side of the interface layer 303 is electrically connected to the interconnect layer 301, and the other side of the interface layer 303 is mechanically connected to the entrance end 21 of the acoustic structure 20. The structural dimensions of the interface layer 303 are set according to the structural dimensions of the entrance end 21 of the acoustic structure 20. (e.g.) Figure 4b The entrance end 21 of the acoustic structure 20 has a circular end face, such as... Figure 5b Interface layer 303 is also circular.

[0066] exist Figure 4a and Figure 5a Based on the illustrated embodiment, the ratio between the first distance and the second distance in the projected contour of the outlet end 22 of the acoustic structure 20 in the XY plane is further adjusted to actively shape an ideal sound field to meet the needs of specific application scenarios. Similarly, in Figure 4b and Figure 5b Based on the embodiment shown, the ratio between the first distance and the second distance in the projection profile of the outlet end 22 of the acoustic structure 20 in the XY plane is further adjusted to actively shape an ideal sound field to meet the needs of specific application scenarios.

[0067] This application also provides an ultrasonic gas flow meter 100, including the sensor packaging structure 300 of any of the above.

[0068] Please see Figure 6 , Figure 6 This is a schematic diagram of the structure of an ultrasonic gas flow meter 100 provided in one embodiment of the present application, applied to a reflective ultrasonic gas flow meter. Figure 6The ultrasonic gas flow meter 100 includes: a sensor structure 10, an acoustic structure 20, a test body 30, a first connecting body 31, a second connecting body 32, and a test pipe 40. This ultrasonic gas flow meter 100 is a reflective ultrasonic gas flow meter, or a "V"-shaped ultrasonic gas flow meter, or a "Z"-shaped ultrasonic gas flow meter. Figure 6 As shown, the ultrasonic gas flow meter 100 can be integrated into the test pipeline 40 through the first connector 31 and the second connector 32 to test the fluid to be tested in the test pipeline 40.

[0069] The ultrasonic gas flow meter 100 employs a dual-diameter acoustic structure 20 to carry a miniature thin-film sensor chip (sensor structure 10), and is optimized in conjunction with the mechanical structure of the test pipe 40 to reduce the impact of beam drift on the signal when the flow velocity increases, thereby improving measurement accuracy and expanding the flow measurement range. It achieves both fluid stability and good acoustic gain. Furthermore, by designing the sensor structure 10 and acoustic structure 20 according to the technical solutions in any of the above embodiments, it can be adapted to test pipes of different sizes.

[0070] Please see Figure 7 , Figure 7 This is a schematic diagram of the structure of an ultrasonic gas flow meter 100 provided in one embodiment of this application, applied to a through-beam ultrasonic gas flow meter.

[0071] The ultrasonic gas flow meter 100 includes: a sensor structure 10, an acoustic structure 20, a fluid stabilization structure 20a, a rectifier 50, and a test body 30. The rectifier 50 includes a rectifier body 51 and a rectifier channel 52.

[0072] The test body 30 provides a flow channel for the fluid to be tested. The shape of the test body 30 is variable; it can be a cylindrical pipe, a cuboid pipe, or other regular / irregular pipes. The dimensions of the test body 30 can also be varied according to the actual application scenario. Furthermore, the inner diameter of the test body 30 can be variable. For example, the test body 30 may include a first pipe section with a first diameter, a second pipe section with a changing diameter, and a third pipe section with a second diameter, wherein the end face diameter of one end of the second pipe section with the changing diameter is equal to the first diameter, and the end face diameter of the other end of the second pipe section with the changing diameter is equal to the second diameter. In an embodiment where the inner diameter of the test body 30 is variable, two sensors are respectively disposed on the first and second pipe sections, and the two sensors can form an opposing beam. The rectifier 50 can be movably mounted on the test body 30. The rectifier 50 can also be fixedly mounted on the test body 30.

[0073] The sensor structure 10, rectifier 50, and test body 30 can be pre-integrated. Users do not need to separately install and calibrate complex rectifiers, sensor mounts, and sensors on-site. Furthermore, there are various ways to mount the sensor structure 10 to the acoustic structure 20, to mount the sensor structure 10 and acoustic structure 20 to the rectifier 50, and to mount the rectifier 50 to the test body 30 (e.g., snap-fit, adhesive, etc.), simplifying the installation process. When mounted on the rectifier 50, the fluid to be measured flows from the acoustic structure 20 to the fluid stabilization structure 20a. In some embodiments, the sensor structure 10 is directly projected, applicable to through-beam ultrasonic gas flow meters. In other embodiments, the sensor structure 10 is obliquely projected, applicable to reflective ultrasonic gas flow meters 100. Furthermore, by designing the sensor structure 10 and acoustic structure 20 according to the technical solutions in any of the above embodiments, it is possible to adapt to test pipes of different sizes.

[0074] The above Figure 6 and Figure 7 The sensor structure 10 of the ultrasonic gas flow meter 100 involved can adopt the sensor packaging structure 300 in any of the above embodiments. This embodiment protects the complete ultrasonic gas flow meter 100 product including any of the aforementioned innovative sensor packaging structures 300. Its effect is to ultimately integrate and embody the technical advantages (high reliability, excellent acoustic performance, strong environmental robustness, easy maintenance, etc.) brought by all the aforementioned sensor packaging structures 300 into the end product ultrasonic gas flow meter 100, thereby improving the overall market competitiveness, performance indicators, and reliability commitment of the ultrasonic gas flow meter 100 product using this technology.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A sensor package structure applied to an ultrasonic gas flowmeter, characterized by, The ultrasonic gas flowmeter comprises a sensor structure and an acoustic structure; The sensor package structure comprises: one or more thin-film sensors; an interconnection layer electrically connected with the one or more thin-film sensors; and an interface layer arranged on a side of the interconnection layer away from the one or more thin-film sensors, one surface of the interface layer being electrically connected with the interconnection layer, and the other surface of the interface layer being mechanically connected with an inlet end of the acoustic structure; wherein the thickness of the interconnection layer in the stacking direction is h1, and h1≥0.2mm; the thickness of the interface layer in the stacking direction is h2, the thickness of the acoustic structure in the stacking direction is H, and h1+h2<H.

2. The sensor package structure of claim 1, wherein, The one or more thin-film sensors comprise one single-diaphragm thin-film sensor, one multi-diaphragm thin-film sensor, a plurality of single-diaphragm thin-film sensors, or any combination of the above three thin-film sensors.

3. The sensor package structure of claim 2, wherein, The one or more thin-film sensors comprise one single-diaphragm thin-film sensor; The single-diaphragm thin-film sensor has a back cavity, and the diameter of the back cavity is d; The interconnection layer has a first cavity exposing the diaphragm cavity, and the extension length of the first cavity in the X direction or the Y direction is d1; wherein d1=d±0.3mm.

4. The sensor package structure of claim 2, wherein, The one or more thin-film sensors comprise one multi-diaphragm thin-film sensor; The multi-diaphragm thin-film sensor has a plurality of back cavities, and the total diameter of the plurality of back cavities is d; The interconnection layer has a first cavity exposing the plurality of diaphragm cavities, and the extension length of the first cavity in the X direction or the Y direction is d1; wherein d1=d±0.3mm.

5. The sensor package structure of claim 2, wherein, The one or more thin-film sensors comprise a plurality of single-diaphragm thin-film sensors; Each single-diaphragm thin-film sensor of the plurality of single-diaphragm thin-film sensors has a back cavity, and the diameter of each back cavity is d; The interconnection layer has a plurality of first cavities for exposing each diaphragm cavity of the plurality of single-diaphragm thin-film sensors, and the extension length of each first cavity in the X direction or the Y direction is d11; wherein d11=d±0.3mm; The distance between the two farthest first cavities of the plurality of first cavities is d1.

6. The sensor package structure according to any one of claims 3-5, wherein, The interface layer has a second cavity exposing the diaphragm cavities and the first cavities, and the extension length of the second cavity in the X direction or the Y direction is d2; wherein d2=d1±0.3mm.

7. The sensor package structure of claim 6, wherein, The sensor package structure further comprises: a cover arranged on a side of the one or more thin-film sensors away from the interconnection layer, the cover covering the one or more thin-film sensors, and the cover having a contact surface with the interconnection layer.

8. The sensor package structure of claim 7, wherein, The sensor package structure further comprises: an encapsulation glue arranged on a side of the cover away from the one or more thin-film sensors, the encapsulation glue covering the cover, and the encapsulation glue having contact surfaces with the cover, the interconnection layer, and the interface layer.

9. The sensor package structure of claim 6, wherein, The size of the entrance end of the acoustic structure in the X-Y plane matches the size of the interface layer in the X-Y plane.

10. The sensor package structure of claim 1, wherein, The one or more thin-film sensors comprise a thin-film sensor array; The thin-film sensor array comprises one multi-diaphragm thin-film sensor, a plurality of single-diaphragm thin-film sensors, or a combination of one single-diaphragm thin-film sensor and one multi-diaphragm thin-film sensor and a plurality of single-diaphragm thin-film sensors; The projected profile of the exit end of the acoustic structure in the X-Y plane has a length in the X direction of a first distance and a length in the Y direction of a second distance; The size of the acoustic field angle of the final output of the ultrasonic gas flow meter is related to (a) the arrangement symmetry of the thin-film sensor array in the X-Y plane and (b) the ratio between the first distance and the second distance.

11. An ultrasonic gas flow meter characterized by, A sensor package structure as claimed in any one of claims 1-10 is employed.

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