Sensor assembly

Abstract

The present application provides a sensor assembly, the sensor assembly comprising a first sensor and a housing, the housing comprising: a bearing portion bearing the first sensor on a first surface; the supporting column is connected with the bearing part, the supporting column extends in the first direction, and the first direction is perpendicular to the first surface; the reflecting plate is connected with the supporting column and extends in the direction perpendicular to the first direction, when observed in the first direction, the reflecting plate and the first sensor are at least partially overlapped, and the first sensor emits sound waves towards the reflecting plate and receives the sound waves reflected by the reflecting plate. The method is simple in structure and accurate in calculation result.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sensors, and in particular to a sensor assembly. BACKGROUND

[0002] Accurate real-time detection of liquid parameters is critical to ensure the safe and effective operation of liquid storage systems. The chemical and food industries, for example, have a need for simultaneous detection of liquid level and concentration. However, there are many small liquid storage systems in the fields of aviation, food and chemical industry, such as diesel exhaust fluid storage tanks, medical equipment such as medical respirators, and liquid storage boxes. Conventional ultrasonic sensors are bulky, and deploying multiple sensors in such cases would greatly occupy the liquid storage space or even make installation impossible.

[0003] Micromachined ultrasonic transducers (MUTs) have shown great advantages in miniaturization and integration compared to traditional bulk ultrasonic transducers. Currently, micromachined ultrasonic transducers can be divided into two categories: capacitive micromachined ultrasonic transducers (CMUTs) and piezoelectric micromachined ultrasonic transducers (PMUTs). Compared with CMUTs, PMUTs do not require DC bias, can be driven at low voltage, have high receiving sensitivity, low output impedance, strong anti-interference ability, and good linearity. PMUTs meet the needs of future intelligent sensors for miniaturization, integration, multifunctionality, and intelligence, and can well solve the problem of detecting liquid characteristic parameters in small-volume liquid storage systems.

[0004] Capacitance method, inductance method, light refraction method, grating transmission spectrum method, and ultrasonic method are the most commonly used technologies for measuring liquid parameters. The choice of detection technology depends on specific functional requirements and application environments. Many researches and products only focus on measuring a single aspect of the liquid.

[0005] With the increasing demand for simultaneously obtaining multiple related parameters of the liquid, there is an increasing demand for multifunctional sensors and multifunctional sensor fusion technologies. There are multifunctional sensors in the prior art. For example, in one technology, the sensor indirectly determines the liquid level and concentration by measuring the capacitance value between two parallel plate electrodes; in another technology, the sensor determines the concentration value by measuring the capacitance change between the winding coil and the center electrode rod, and obtains the liquid level by measuring the effect of the liquid on the inductance of the coil.

[0006] The sensors based on the principle of capacitance and inductance are vulnerable to electromagnetic interference, and the measurement range is limited by the size of the sensor itself. In other technologies, the change of light output power is measured by using the influence of liquid on the refractive index of light, so that the concentration and liquid level of glycerol solution can be determined; or the simultaneous measurement of liquid level and concentration is also realized by the change of resonant wavelength under different order envelope modes through the coupling intensity of grating transmission spectrum. The sensors based on the principle of light refractive index and grating transmission spectrum are vulnerable to environmental light interference, and the measurement range is also limited by the size of the sensor itself.

[0007] The measurement based on ultrasound has strong anti-interference ability, but most of them are single parameter measurement. For example, based on acoustic impedance, multiple sensors can be distributed outside the container side wall, and the liquid level position can be detected by the different energy sizes of the reflected sound waves caused by the different acoustic impedances of liquid and air; or the ultrasonic sensor is placed above the liquid surface, and the distance between the sensor and the liquid surface is measured based on the sound wave flight time, so as to indirectly determine the liquid level, which is also the mainstream measurement method of the current commercial ultrasonic liquid level sensor, but this method needs to be calibrated for the distance between the sensor and the bottom of the container for each application scenario; or based on acoustic impedance method, the sensor is placed outside the wall at the bottom of the container, and the concentration is measured by measuring the change of echo energy caused by the different acoustic impedances of solutions with different concentrations; or based on the sound speed method, the sensor is placed in the solution, and the solution concentration is measured by measuring the change of sound speed in the solution.

[0008] It should be noted that the above introduction to the technical background is only for the convenience of clearly and completely describing the technical scheme of the present application, and for the convenience of understanding by those skilled in the art. The above technical scheme cannot be considered as known to those skilled in the art only because it is described in the background section of the present application. SUMMARY

[0009] The inventors found that the existing technologies for measuring liquid based on ultrasound have some limitations, specifically: some technologies have complex settings, for example, sensors need to be set at different heights to detect the liquid level at the corresponding height; some technologies have complex operations, for example, the distance between the sensor and the bottom of the container needs to be calibrated for each application scenario; some technologies place the sensor outside the container and rely on the measurement of related parameters by the amplitude of the echo signal, which is easily disturbed by external interference, resulting in that the detection result is easily disturbed; some technologies place the sensor in the solution, but there are many difficulties in measuring the sound speed in the solution. Therefore, how to simply and accurately measure the physical parameters of the liquid is a problem to be solved.

[0010] To address the above issues or at least similar issues, an embodiment of the present application provides a sensor assembly. By disposing a reflecting plate opposite to a sensor in a housing of the sensor assembly, sound waves emitted by the sensor can propagate in a predetermined propagation path between the sensor and the reflecting plate, so as to facilitate calculation of a sound wave speed in a medium between the sensor and the reflecting plate, thereby facilitating calculation of a physical parameter of the medium.

[0011] According to an aspect of an embodiment of the present application, a sensor assembly is provided, the sensor assembly comprising a first sensor and a housing,

[0012] The housing comprises:

[0013] a carrier portion carrying the first sensor on a first surface;

[0014] a support column connected with the carrier portion, the support column extending in a first direction, the first direction being perpendicular to the first surface; and

[0015] a reflecting plate connected with the support column, extending in a direction perpendicular to the first direction, the reflecting plate at least partially overlapping the first sensor when viewed in the first direction,

[0016] the first sensor emits sound waves towards the reflecting plate and receives sound waves reflected from the reflecting plate.

[0017] In an embodiment, the sensor assembly further comprises:

[0018] a controller configured to calculate a propagation speed of sound waves in a first medium between the first sensor and the reflecting plate according to a propagation time of the sound waves in the first medium, and determine a physical parameter of the first medium.

[0019] In an embodiment, the first medium is a liquid, and the physical parameter of the first medium comprises a concentration of the liquid.

[0020] In an embodiment, the sensor assembly further comprises:

[0021] a second sensor disposed on the first surface of the carrier portion, the reflecting plate and the second sensor not overlapping with each other when viewed in the first direction.

[0022] In an embodiment, the controller is configured to calculate a size of the first medium in the first direction according to a time taken for a sound wave emitted from the second sensor to be reflected at an interface between the first medium and a second medium to be received by the second sensor, and a propagation speed of the sound wave.

[0023] In one embodiment, the first surface of the carrier portion is provided with a flexible circuit board, and the first sensor and / or the second sensor is electrically connected with the flexible circuit board.

[0024] In one embodiment, the carrier portion has a box shape,

[0025] The first surface is a bottom surface of an inside of the box shape,

[0026] A side wall of the box shape is provided with an opening,

[0027] The opening is for a cable to pass through, and the cable is electrically connected with the flexible circuit board.

[0028] In one embodiment, the sensor assembly further has a sealing portion covering the first sensor and / or the second sensor surface and filling a gap between the cable and the opening.

[0029] In one embodiment, the first sensor and / or the second sensor is a piezoelectric ultrasonic transducer.

[0030] In one embodiment, there is a gap of a predetermined size between the first sensor and the second sensor.

[0031] The application has the beneficial effect that a reflecting plate opposite to the sensor is arranged on the housing of the sensor assembly, and the sound wave emitted by the sensor can propagate in a predetermined propagation path between the sensor and the reflecting plate, which facilitates calculation of the sound wave speed in the medium between the sensor and the reflecting plate, and thus facilitates calculation of the physical parameters of the medium.

[0032] Specific embodiments of the application are disclosed in detail in the following description and claims, with reference to the accompanying drawings. It should be understood that the embodiments of the application are not limited in scope to the specific embodiments described herein. Embodiments of the application include many alternatives, modifications, and equivalents.

[0033] Features described and / or illustrated with respect to one implementation can be used in the same or similar manner in one or more other implementations, in combination with or in place of features in other implementations, or in place of features in other implementations.

[0034] It should be emphasized that the term "comprises / comprising" when used in this text is taken to mean the presence of stated features, integers, steps or components, but not to the exclusion of one or more other features, integers, steps or components, or groups thereof. BRIEF DESCRIPTION OF DRAWINGS

[0035] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. It is to be understood that the drawings are solely for purposes of illustration and are not intended to limit the application. In the drawings:

[0036] Figure 1 is a schematic view of a sensor assembly of the present application;

[0037] Figure 2 is a schematic view of a cross section along the A-A direction of Figure 1

[0038] Figure 3 is a schematic view of test results of the sensor assembly 100 of the present application;

[0039] Figure 4 is a schematic view of a minimum sound wave flight time variation that can be detected by the sensor assembly 100. DETAILED DESCRIPTION

[0040] The foregoing and other features of the present application will become apparent to those skilled in the art upon consideration of the following description of specific embodiments of the application, taken in conjunction with the accompanying drawings. In the drawings, like reference numerals identify like elements throughout. The specific embodiments of the application described herein are illustrative of the principles of the application and are not intended to limit the application to the particular embodiments described. The present application includes all modifications and variations of the specific embodiments described and incorporates the scope of the appended claims by reference.

[0041] In the description of the embodiments of the present application, for the convenience of description, the direction parallel to the first surface of the carrier portion is referred to as the "lateral direction", the direction perpendicular to the first surface of the carrier portion is referred to as the "vertical direction", the dimension in the "vertical direction" can be referred to as "height" or "thickness"; in the "vertical direction", the direction from the first surface of the carrier portion to the reflecting plate is referred to as the "up" direction, and the opposite direction of the "up" direction is referred to as the "down" direction.

[0042] It should be noted that the "up" direction and the "down" direction described above are only for the convenience of description, and do not limit the orientation or posture of the sensor assembly of the present application during manufacturing or use.

[0043] Embodiments of the present application provide a sensor assembly.

[0044] Figure 1 is a schematic view of a sensor assembly of the present application. As Figure 1 shown, the sensor assembly 100 can include a first sensor 1 and a housing 2.

[0045] ​The first sensor 1 can be an ultrasonic transducer. For example, the first sensor 1 can have a sound wave transmitting unit and a sound wave receiving unit. The sound wave transmitting unit can emit sound waves, and the sound wave receiving unit can receive sound waves and convert the received sound waves into electrical signals. The sound wave transmitting unit can have multiple ultrasonic transducer units, and the sound wave receiving unit can also have multiple ultrasonic transducer units. The sound wave transmitting unit and the sound wave receiving unit can have the same structure. In some embodiments, the multiple ultrasonic transducer units in the ultrasonic transducer can be used as both sound wave transmitting units and sound wave receiving units, or, among the multiple ultrasonic transducer units in the ultrasonic transducer, some ultrasonic transducer units are used as sound wave transmitting units, and other ultrasonic transducer units are used as sound wave receiving units.

[0046] In some examples, the ultrasonic transducer can be a capacitive micromachined ultrasonic transducer (CMUT) or a piezoelectric micromachined ultrasonic transducer (PMUT). In the examples below, the first sensor 1 is described as a PMUT; that is, the first sensor 1 may include multiple piezoelectric micromachined ultrasonic transducer units, which can form a piezoelectric micromachined ultrasonic transducer unit array.

[0047] The surface of the first sensor 1 can be square, for example, 2.8mm × 2.8mm. Alternatively, the surface of the first sensor 1 can be other shapes or sizes.

[0048] like Figure 1 As shown, the housing 2 includes: a support portion 21, a support column 22, and a reflector 23.

[0049] The first surface 210 of the support portion 21 can support the first sensor 1. For example, the first sensor 1 can be directly mounted on the first surface 210, or the first sensor 1 can be mounted on the first surface 210 by other components (e.g., a flexible circuit board described later).

[0050] In one example, the support portion 21 may have a box shape, for example, the box shape having a rectangular bottom and four side walls respectively connected to the four sides of the bottom. The first surface 210 may be the bottom surface (i.e., the upper surface of the bottom) inside the box shape. The first sensor 1 may be disposed inside the box shape and surrounded by the four side walls.

[0051] The support column 22 is connected with the bearing part 21. The support column 22 can extend along a first direction D1, which can be perpendicular to the first surface 210. In some embodiments, the support column 22 can be formed separately from the bearing part 21, and the support column 22 can be installed on the bearing part 21 by means of gluing or by means of installation components such as screws or clamping grooves. In other embodiments, the support column 22 can be integrally formed with the bearing part 21.

[0052] The reflecting plate 23 can be connected with the support column 22 and extend along a direction perpendicular to the first direction D1 (i.e., transversely), for example, the reflecting plate 23 can extend above the first sensor 1, i.e., the reflecting plate 23 at least partially overlaps the first sensor 1 when viewed along the first direction D1. In one specific example, the reflecting plate 23 extends along a direction perpendicular to the first direction D1 (i.e., transversely) until the edge of the reflecting plate 23 is in the same position as the edge of the first sensor 1 in the transverse direction. The reflecting plate 23 can be a metal material, for example, stainless steel or the like.

[0053] In this application, the first sensor 1 can emit sound waves toward the reflecting plate 23 and receive sound waves reflected from the reflecting plate.

[0054] According to embodiments of the present application, the reflecting plate 23 opposite to the first sensor 1 is arranged on the housing 2 of the sensor assembly 100, so that a preset propagation path for sound wave propagation is formed between the first sensor 1 and the reflecting plate 23, and the sound waves emitted by the first sensor 1 are reflected by the reflecting plate 23 and then received by the first sensor 1. Thus, the sound waves can propagate in the preset propagation path between the first sensor 1 and the reflecting plate 23, and the complex setting steps and restrictions can be avoided, and the speed of sound waves in the medium between the sensor and the reflecting plate can be calculated, thereby facilitating the calculation of the physical parameters of the medium. For example, the speed of sound waves in the first medium between the first sensor and the reflecting plate can be calculated according to the propagation time of the sound waves in the first medium, and the physical parameters of the first medium can be determined.

[0055] In some embodiments, the sensor assembly 100 can be placed in a first medium in which sound waves propagate, and the first sensor 1 and the reflecting plate 23 are filled with the first medium. The first sensor 1 can emit sound waves toward the reflecting plate 23 at time t0, the sound waves propagate in the first medium to the reflecting plate 23 and are reflected by the reflecting plate 23, and the first sensor 1 receives the sound waves reflected by the reflecting plate 23 at time t1. Since the distance L1 between the first sensor 1 and the reflecting plate 23 along the first direction is a known value, the controller 3 of the sensor assembly 100 can calculate the speed v of the sound waves propagating in the first medium according to v = 2*L1 / (t1-t0).

[0056] Further, the controller 3 can determine the physical parameter of the first medium according to a correspondence between the physical parameter of the first medium and a speed v at which the acoustic wave propagates in the first medium.

[0057] In some examples, the first medium is a liquid, and the physical parameter of the first medium is a concentration of the liquid. In addition, the present application is not limited thereto, for example, the first medium can also be a gas or a solid or a solid-liquid mixture, etc., and the physical parameter of the first medium can also be a density, etc.

[0058] In the present application, the controller 3 can control the time at which the first sensor 1 emits the acoustic wave, and can record the time at which the first sensor 1 receives the acoustic wave, so the controller 3 can obtain the two time points t0 and t1.

[0059] In the present application, as shown in Figure 1 The sensor assembly 100 further comprises a second sensor 4.

[0060] The second sensor 4 can be an ultrasonic transducer, for example, the second sensor 4 can have an acoustic wave transmitting unit and an acoustic wave receiving unit, the acoustic wave transmitting unit can emit an acoustic wave, and the acoustic wave receiving unit can receive an acoustic wave and convert the received acoustic wave into an electrical signal. The acoustic wave transmitting unit can have a plurality of ultrasonic transducer units, and the acoustic wave receiving unit can have a plurality of ultrasonic transducer units. The acoustic wave transmitting unit and the acoustic wave receiving unit can have the same structure. In some embodiments, the plurality of ultrasonic transducer units in the ultrasonic transducer can be used as both the acoustic wave transmitting unit and the acoustic wave receiving unit, or a part of the plurality of ultrasonic transducer units in the ultrasonic transducer can be used as the acoustic wave transmitting unit, and another part of the plurality of ultrasonic transducer units in the ultrasonic transducer can be used as the acoustic wave receiving unit.

[0061] In some examples, the ultrasonic transducer can be a capacitive micromachined ultrasonic transducer (CMUT) or a piezoelectric micromachined ultrasonic transducer (PMUT). In the following examples of the present application, the second sensor 2 is taken as an example of a PMUT, that is, the second sensor 4 can include a plurality of piezoelectric micromachined ultrasonic transducer units, and the plurality of piezoelectric micromachined ultrasonic transducer units can constitute a piezoelectric micromachined ultrasonic transducer unit array.

[0062] The surface of the second sensor 4 can be square, for example, 2.8 mm x 2.8 mm, and in addition, the surface of the first sensor 1 can also be other shapes or sizes.

[0063] As shown in Figure 1As shown, the second sensor 4 is arranged on the first surface 210 of the carrier 21, for example, the second sensor 4 can be directly mounted on the first surface 210, or the second sensor 4 can be mounted on the first surface 210 through other components (for example, a flexible circuit board described later).

[0064] When viewed along the first direction D1, the reflection plate 23 and the second sensor 4 do not overlap with each other, that is, the second sensor 4 and the reflection plate 23 are arranged laterally staggered. Thus, when the second sensor 4 is located in the first medium, the sound waves emitted by the second sensor 4 towards the upper direction will not be blocked or reflected by the reflection plate 23, and the sound waves are reflected at the interface between the first medium and the second medium.

[0065] The controller 3 can calculate the distance of the second sensor 4 to the interface between the first medium and the second medium in the first direction according to the time from the emission of the sound wave from the second sensor 4 to the reflection of the sound wave at the interface between the first medium and the second medium being received by the second sensor 4, and the propagation speed of the sound wave in the first medium.

[0066] In the present application, the speed of the sound wave propagating in the first medium and the second medium is different. For example, the first medium is a liquid, and the second medium is air outside (for example, above) the liquid.

[0067] In some embodiments, the sensor assembly 100 can be placed in a first medium in which sound propagates, and the second sensor 4 has the first medium above it. The second sensor 4 can emit a sound wave upwards at time t2, the sound wave propagates in the first medium to be reflected at the interface between the first medium and the second medium, and the second sensor 4 receives the sound wave reflected from the interface between the first medium and the second medium at time t3. The controller 3 can calculate the distance L2 of the second sensor 4 to the interface between the first medium and the second medium according to L2 = v*(t3-t2) / 2. Wherein v is the speed of the sound wave propagating in the first medium, which can be calculated by the above formula v = 2*L1 / (t1-t0); L2 represents the distance from the interface between the first medium and the second medium to the second sensor 4, wherein in the case of placing the sensor assembly 100 at the bottom of the container, the distance L0 between the second sensor 4 and the bottom of the sensor assembly 100 is known, so the height H of the first medium (i.e. the liquid level) in the container is H = L0+L2.

[0068] In the present application, the sensor assembly 100 has two sensors, the first sensor 1 and the second sensor 4, the first sensor 1 can be used to measure the concentration of the first medium, and the second sensor can be used to measure the height of the first medium, thereby realizing multi-parameter measurement for the same medium (for example, the same kind of liquid).

[0069] In the present application, as Figure 1As shown, there is a gap with a predetermined size between the first sensor 1 and the second sensor 4, for example, the size of the gap W1 between the first sensor 1 and the second sensor 4 is 4mm. In this way, the first sensor 1 and the second sensor 4 do not interfere with each other. The size of the gap W1 can be obtained based on simulation results.

[0070] In the present application, the frequencies of the sound waves emitted by the first sensor 1 and the second sensor 4 can be the same or different.

[0071] In the present application, the first surface 210 of the bearing portion 21 is provided with a flexible circuit board 211, and the first sensor 1 and / or the second sensor 4 are electrically connected with the flexible circuit board 211. The connection part of the flexible circuit board 211 with the cable 6 can withstand a large bending angle, so that when the sensor assembly 100 is arranged at the bottom of the container, external leads can also be realized through the cable 6; in addition, the overall thickness of the sensor assembly 100 can also be controlled as much as possible.

[0072] In the present application, the side wall of the box-shaped bearing portion 21 is provided with an opening 212, which can be passed through by the cable 6. In this way, the cable 6 can be electrically connected with the flexible circuit board 211, for example, the cable 6 can electrically connect the first sensor 1 and the second sensor 4 with the controller 3; in addition, the cable 6 can also power the first sensor 1 and the second sensor 4.

[0073] In the present application, the sensor assembly 100 also has a sealing portion (not shown), which can be formed by a material such as sealing glue, etc. The sealing portion can cover the surface of the first sensor 1 and / or the second sensor 4, and fill the gap between the cable 6 and the opening 212. In this way, when the sensor assembly 100 is placed at the bottom of the container, the liquid (i.e. the first medium) in the container is blocked by the sealing portion, and does not affect the operation of the first sensor 1 and the second sensor 4.

[0074] Figure 1An example of relevant parameters of this application is shown. For example, the width W of the reflector 23 is 4 mm, the distance L1 from the reflector 23 to the first sensor 1 is 6 mm, the thickness H1 of the support part 21 is 4 mm, the width W2 of the support part 21 is 9 mm, and the length L3 of the support part 21 is 13 mm. The width W of the reflector 23 can be obtained based on simulation results. For example, the sound pressure of the sound wave received at the edge of the reflector 23 in the width direction is 3 dB lower than the sound pressure of the sound wave received at the center of the reflector 23 in the width direction. The distance L1 from the reflector 23 to the first sensor 1 can be set based on the wavelength of the sound wave. For example, the wavelength of the sound wave emitted by the first sensor 1 plus a certain margin is equal to twice the distance L1. In a specific example, the wavelength of the sound wave emitted by the first sensor 1 is 9 mm, and the margin is 3 mm. Therefore, 9 mm + 3 mm = 2 * L1 = 12 mm, and thus L1 is 6 mm.

[0075] It should be noted that the specific values ​​of the above parameters are just examples, and each parameter can have other values.

[0076] Figure 2 It is along Figure 1 A schematic diagram of the cross-section in the AA direction, as shown below. Figure 2 As shown, when the sensor assembly 100 is placed at the bottom of the container containing the first medium:

[0077] On one hand, the space between the first sensor 1 and the reflector 23 is filled with the first medium. The sound wave emitted by the first sensor to the reflector 23 propagates in the first medium to the reflector 23 and is reflected by the reflector 23. Then the first sensor 1 receives the sound wave reflected by the reflector 23. Thus, the controller 3 can calculate the speed v of the sound wave propagating in the first medium and then confirm the physical parameters of the first medium, such as the concentration of the liquid.

[0078] On the other hand, the second sensor 4 emits sound waves upwards into the first medium. The sound waves propagate in the first medium and are reflected at the interface between the first medium (e.g., liquid) and the second medium (e.g., gas). The second sensor 4 receives the sound waves reflected from the interface between the first medium and the second medium. The controller 3 can combine the calculation result of the speed v of the sound waves propagating in the first medium to calculate the distance L2 from the second sensor 4 to the interface between the first medium and the second medium, and then calculate the height of the first medium in the container.

[0079] In this application, the sensor assembly 100 may also have a back-end circuit (not shown), which may be a commercial circuit, etc., and will not be described in detail in this application.

[0080] Figure 3 This is a schematic diagram showing the test results of the sensor assembly 100 of this application.Figure 3 In the tests shown, a concentration-sound velocity mapping relationship was calibrated at room temperature for glycerol solution and NaCl solution (26% saturated concentration at room temperature), and functional tests of the concentration and liquid level of the sensor assembly 100 were performed.

[0081] As shown in FIG. 6, 30 sets of measurements were performed for each test point, and the fitting formula showed that the average value of the measurements was highly consistent with the actual value. The box plot was the difference between the 30 sets of data and the actual value, and the results showed that the measurement error of the concentration and liquid level of the glycerol solution / NaCl solution was ±0.5% / ±1.1% and ±0.5mm / ±0.5mm. Figure 3

[0082] Figure 4 The minimum sound wave flight time variation that the sensor assembly 100 can detect is shown in FIG. 7. As shown in FIG. 7, the minimum sound wave flight time variation that the sensor assembly 100 can detect was 0.038μs (i.e., the difference between 14.484851μs and 14.522765μs), and thus the concentration resolution of the sensor assembly 100 for the glycerol solution and the NaCl solution was 0.323% and 0.914% respectively (e.g., the concentration resolution can be derived based on the fitting formula between the sound velocity and the concentration, and the specific derivation method can refer to the related art), and the liquid level resolution of the sensor assembly 100 for the glycerol solution and the NaCl solution was 0.077mm and 0.070mm respectively. Figure 4

[0083] The sensor assembly 100 of the present application can simultaneously measure the liquid concentration and the liquid level while achieving miniaturization, and the measurement method is simple and the measurement result is accurate.

[0084] The present application has been described above with reference to specific embodiments. However, it should be clear to those skilled in the art that these descriptions are exemplary and not limiting to the scope of protection of the present application. Those skilled in the art can make various modifications and changes to the present application according to the spirit and principles of the present application, and these modifications and changes are also within the scope of the present application.​​

Claims

1. A sensor assembly, characterized in that, The sensor assembly includes a first sensor and a housing. The housing includes: A support portion, which supports the first sensor on a first surface; A support column, connected to the bearing portion, extending along a first direction perpendicular to the first surface; and A reflector, connected to the support column, extends along a direction perpendicular to the first direction, and when viewed along the first direction, the reflector at least partially overlaps with the first sensor. The first sensor emits sound waves toward the reflector and receives sound waves reflected from the reflector.

2. The sensor assembly as claimed in claim 1, characterized in that, The sensor assembly also includes: The controller calculates the propagation speed of the sound wave in the first medium based on the propagation time of the sound wave in the first medium between the first sensor and the reflector, and determines the physical parameters of the first medium.

3. The sensor assembly as described in claim 2, characterized in that, The first medium is a liquid, and the physical parameters of the first medium include the concentration of the liquid.

4. The sensor assembly as claimed in claim 2, characterized in that, The sensor assembly also includes: The second sensor is disposed on the first surface of the support portion, and when viewed along the first direction, the reflector and the second sensor do not overlap with each other.

5. The sensor assembly as claimed in claim 4, characterized in that, The controller calculates the size of the first medium in the first direction based on the time it takes for the sound wave emitted from the second sensor to be reflected at the interface between the first medium and the second medium and received by the second sensor, and the propagation speed of the sound wave.

6. The sensor assembly as claimed in claim 4, characterized in that, The first surface of the support portion is provided with a flexible circuit board, and the first sensor and / or the second sensor are electrically connected to the flexible circuit board.

7. The sensor assembly as claimed in claim 6, characterized in that, The supporting part has a box shape. The first surface is the bottom surface inside the box shape. The side walls of the box-shaped structure are provided with openings. The opening allows a cable to pass through, and the cable is electrically connected to the flexible circuit board.

8. The sensor assembly as claimed in claim 7, characterized in that, The sensor assembly also has a sealing portion that covers the surface of the first sensor and / or the second sensor and fills the gap between the cable and the opening.

9. The sensor assembly as claimed in claim 4, characterized in that, The first sensor and / or the second sensor are piezoelectric ultrasonic transducers.

10. The sensor assembly as claimed in claim 4, characterized in that, There is a gap of a predetermined size between the first sensor and the second sensor.

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