Electromagnetic ultrasonic sensor packaging method based on impedance monitoring

Abstract

The invention belongs to the field of sensor packaging, and particularly discloses an electromagnetic ultrasonic sensor packaging method based on impedance monitoring, which comprises the following steps: after sequentially adhering a first epoxy sheet, a receiving coil, a second epoxy sheet and a back plate, measuring the real-time impedance of the receiving coil; whether the ratio of the real-time impedance to the corresponding design impedance is larger than a preset Pearson's correlation coefficient or not is judged; if yes, next-step installation is carried out; if not, adjusting the thickness of the second epoxy sheet until the requirement is met; after the exciting coil is adhered to one side, deviating from the receiving coil, of the first epoxy sheet, executing the same measurement and judgment steps to determine whether the distance between the exciting coil and the receiving coil meets the requirement or not; after other parts are installed, real-time impedance of the receiving coil and the exciting coil is measured, the ratio of the real-time impedance to the corresponding design impedance is judged, and the size of the ratio is judged till all the ratios are larger than the preset Pearson's correlation coefficient. According to the invention, the consistency of the design performance and the packaged performance of the sensor can be ensured.

Description

Technical Field

[0001] The present application belongs to the technical field of sensor packaging technology, and more specifically, relates to an electromagnetic ultrasonic sensor packaging method based on impedance monitoring. Background Art

[0002] Electromagnetic ultrasonic sensor is a sensor that uses the principle of electromagnetic induction to generate and receive ultrasonic waves. This sensor has the advantage of non-contact detection and is suitable for detection tasks under harsh working conditions such as high speed and high temperature. The electromagnetic ultrasonic sensor components include magnets, backplanes, coils, etc. During the sensor development process, it is necessary to design the size and position of each sensor component, and the sensor needs to be filled and packaged before actual use. During the sensor packaging process, the filling gap between the components determines the distance between the components, and because the electromagnetic ultrasonic sensor has a large number of coil layers and turns, it is easily affected by the manufacturing errors and manufacturing processes of the printed circuit board, making it difficult to ensure the consistency between the actual performance of the sensor and the design performance, and the sensor performance is difficult to control during the packaging process, which makes it difficult to mass produce and multi-channel array applications of electromagnetic ultrasonic sensors. Summary of the invention

[0003] In view of the defects of the prior art, the purpose of this application is to provide an electromagnetic ultrasonic sensor packaging method based on impedance monitoring, aiming to solve the problem that the electromagnetic ultrasonic sensor packaging process causes the actual performance to be inconsistent with the designed performance and the sensor performance is difficult to control during the packaging process.

[0004] To achieve the above object, the present application provides an electromagnetic ultrasonic sensor packaging method based on impedance monitoring, comprising the following steps:

[0005] S1, after laminating and adhering the back plate, the first epoxy sheet and the receiving coil in sequence, measures the first real-time impedance of the receiving coil, obtains a first ratio between the first real-time impedance and the design impedance of the receiving coil, and determines whether the first ratio is greater than a preset Pearson correlation coefficient: if so, proceeds to the next step of installation; if not, adjusts the thickness of the first epoxy sheet until the first ratio is greater than the preset Pearson correlation coefficient and then proceeds to the next step;

[0006] S2, after adhering the second epoxy sheet and the excitation coil in sequence on one side of the receiving coil, measuring the second real-time impedance of the excitation coil, and obtaining a second ratio of the second real-time impedance to the design impedance of the excitation coil, and judging whether the second ratio is greater than the preset Pearson correlation coefficient: if so, installing the remaining components; if not, adjusting the thickness of the second epoxy sheet until the second ratio is greater than the preset Pearson correlation coefficient and then proceeding to the next step;

[0007] S3 After installing the remaining components in sequence, measure the third real-time impedance of the receiving coil and the fourth real-time impedance of the excitation coil, and obtain a third ratio between the third real-time impedance and the design impedance of the receiving coil, as well as a fourth ratio between the fourth real-time impedance and the design impedance of the excitation coil, and determine whether the third ratio and the fourth ratio are both greater than the preset Pearson correlation coefficient: if both are greater than, package the electromagnetic ultrasonic sensor; if at least one is not greater than, adjust the installation gap between the remaining components until the third ratio and the fourth ratio meet the requirements, and then package the electromagnetic ultrasonic sensor.

[0008] After each packaging step of the electromagnetic ultrasonic sensor, the present application performs real-time measurement of the impedance at both ends of the installed receiving coil and the excitation coil, and calculates the ratio between the real-time impedance of each coil and the corresponding design impedance. By comparing the ratio with the preset Pearson coefficient, it can be determined whether the installation step is qualified, thereby ensuring the consistency between the actual performance of the electromagnetic ultrasonic sensor and the design performance.

[0009] Furthermore, before step S1, the following steps are also performed to screen the receiving coil and the exciting coil:

[0010] Detect the inherent impedance of multiple alternative receiving coils, and obtain the fifth ratio between the inherent impedance of each alternative receiving coil and its designed impedance, and select the alternative receiving coil whose fifth ratio is greater than the preset Pearson correlation coefficient as the receiving coil; detect the inherent impedance of multiple alternative excitation coils, and obtain the sixth ratio between the inherent impedance of each alternative excitation coil and its designed impedance, and select the alternative excitation coil whose sixth ratio is greater than the preset Pearson correlation coefficient as the excitation coil.

[0011] Furthermore, the thickness of the back plate is greater than 5 times the skin depth.

[0012] Furthermore, a frequency sweep measurement method is used to measure each real-time impedance as well as the intrinsic impedance of the receiving coil and the intrinsic impedance of the exciting coil.

[0013] Furthermore, during the frequency sweep measurement, the frequency sweep range is greater than the operating frequency of the electromagnetic ultrasonic sensor.

[0014] Furthermore, the frequency range of the swept frequency measurement is 20 Hz to 5 MHz, and the number of sampling points is 400.

[0015] Furthermore, the preset Pearson correlation coefficient is 0.98.

[0016] Further, in step S3, the remaining components include a housing and a plug.

[0017] In a second aspect, the present application provides an electronic device comprising: at least one memory for storing programs; and at least one processor for executing the programs stored in the memory. When the program stored in the memory is executed, the processor is used to execute the method described in the first aspect or any possible implementation of the first aspect.

[0018] In a third aspect, the present application provides a computer-readable storage medium, which stores a computer program. When the computer program runs on a processor, the processor executes the method described in the first aspect or any possible implementation of the first aspect.

[0019] It can be understood that the beneficial effects of the second to third aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here.

[0020] In general, the above technical solutions conceived by this application have the following beneficial effects compared with the prior art:

[0021] (1) After each packaging step of the electromagnetic ultrasonic sensor, the present application performs real-time measurement of the impedance at both ends of the installed receiving coil and the exciting coil, and calculates the ratio between the real-time impedance of each coil and the corresponding design impedance. By comparing the ratio with the preset Pearson coefficient, it can be determined whether the installation step is qualified, whether the distance between the installed components is appropriate, or whether the size of the components themselves meets the requirements, thereby ensuring the consistency between the actual performance of the electromagnetic ultrasonic sensor and the designed performance;

[0022] (2) The present application includes electromagnetic ultrasonic sensor impedance calibration, packaging process, and impedance monitoring and judgment links, cross-integrating packaging and packaging detection so that the impedance measurement and judgment steps are performed after each packaging link of the electromagnetic ultrasonic sensor. The quality of any packaging link can be controlled, and the next packaging step can be executed only after each packaging link meets the packaging requirements, thereby ensuring the multi-channel consistency of the electromagnetic ultrasonic sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of a process flow of an electromagnetic ultrasonic sensor packaging method based on impedance monitoring provided by the present application;

[0024] Figure 2 It is a schematic diagram of the spatial arrangement of the excitation coil, receiving coil, back plate and external test piece of the electromagnetic ultrasonic sensor provided by the present application;

[0025] Figure 3 This application provides Figure 2 Schematic diagram of equivalent circuit of each component in electromagnetic ultrasonic sensor;

[0026] Figure 4This is a schematic diagram of the structure of an electromagnetic ultrasonic body wave thickness sensor after packaging provided by the present application;

[0027] Figure 5 It is a schematic diagram of the designed impedance measured at both ends of the sensor excitation coil and the receiving coil provided by the present application;

[0028] Figure 6 It is a schematic diagram of impedance at both ends of the excitation coil and the receiving coil after the sensor packaging provided by the present application is completed;

[0029] Figure 7 It is a schematic diagram of the detection signals of the three sensors after packaging and the sensor design signals provided by the present application.

[0030] In the figure: 1-first epoxy sheet, 2-receiving coil, 3-second epoxy sheet, 4-exciting coil, 5-back plate, 6-external test piece, 7-magnet, 8-housing, 9-plug, third epoxy sheet 10. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0032] The term "and / or" in this article is a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The symbol " / " in this article indicates that the associated objects are in an or relationship, for example, A / B means A or B.

[0033] The terms "first" and "second" in the specification and claims herein are used to distinguish different objects rather than to describe a specific order of the objects. For example, a first response message and a second response message are used to distinguish different response messages rather than to describe a specific order of the response messages.

[0034] In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0035] In the description of the embodiments of the present application, unless otherwise specified, "multiple" means two or more than two. For example, multiple processing units refer to two or more processing units, etc.; multiple elements refer to two or more elements, etc.

[0036] The technical solution of the present application is described in detail through the following embodiments.

[0037] This embodiment provides an electromagnetic ultrasonic sensor packaging method based on impedance monitoring, which includes the following steps before packaging begins:

[0038] An electromagnetic ultrasonic sensor is designed, and during the design phase of the electromagnetic ultrasonic sensor (hereinafter referred to as the sensor), an optimal Pearson coefficient (i.e., a preset Pearson coefficient) between the coil's own impedance and its designed impedance is determined through experiments. In this application, the preset Pearson coefficient is 0.98; the designed operating frequency of the sensor is 1.2 MHz.

[0039] Then screen the receiving coil and the excitation coil: detect the inherent impedance of multiple alternative receiving coils, and obtain the ratio of the inherent impedance of each alternative receiving coil to the design impedance of the receiving coil 2, that is, the aforementioned fifth ratio, and select the alternative receiving coil with the fifth ratio greater than the preset Pearson correlation coefficient of 0.98 as the receiving coil 2; detect the inherent impedance of multiple alternative excitation coils, and obtain the sixth ratio between the inherent impedance of each alternative excitation coil and the design impedance of the excitation coil 4, and select the alternative excitation coil with the sixth ratio greater than the preset Pearson correlation coefficient as the excitation coil 4.

[0040] Start packaging, such as Figure 1 As shown, the specific steps include:

[0041] After S1 sequentially stacks and installs the back plate 5, the first epoxy sheet 1 and the receiving coil 2, the first real-time impedance of the receiving coil 2 is measured, and the first ratio between the first real-time impedance and the design impedance of the receiving coil 2 is obtained, and it is determined whether the first ratio is greater than the preset Pearson correlation coefficient: if so, proceed to the next step of installation; if not, adjust the thickness of the first epoxy sheet 1 until the first ratio is greater than the preset Pearson correlation coefficient.

[0042] When the sensor is working, the performance of the complete coil structure composed of the excitation coil 4 and the receiving coil 2 is affected by the interaction between the excitation coil 4 and the receiving coil 2 as well as the back plate 5 and the external test piece 6. The main reasons are:

[0043] 1. In the electromagnetic ultrasonic sensor, the excitation coil 4 is used to generate an alternating magnetic field to excite sound waves on the surface of the specimen, while the receiving coil 2 is used to detect the changes in the magnetic field caused by the sound waves. The distance, relative position and structural design between the two will affect the performance of the sensor; in addition, the interaction between the excitation coil 4 and the receiving coil 2 will also affect the frequency characteristics and sound field directivity of the sensor.

[0044] 2. Influence of back plate 5: The material and thickness of coil back plate 5 will affect the performance of the sensor. Back plate 5 is usually used to shield the alternating magnetic field; the magnetic permeability of back plate 5 has a significant effect on the magnetic field generated by the coil, thus affecting the performance of the sensor; the thickness of sensor back plate 5 is generally 0.5mm, which is much larger than the skin depth of 0.06mm at a frequency of 1.2MHz. The skin depth refers to the thickness from the surface of the conductor to the current density dropping to 1 / e of the surface current density (approximately equal to 36.8%), and the back plate 5 can support the coil and provide appropriate magnetic field distribution.

[0045] 3. Influence of the specimen: The material properties (such as electrical conductivity and magnetic permeability) and geometry of the specimen will affect the magnetic field generated by the coil and the distribution of the magnetic field in the specimen. For example, the skin effect is related to the electrical conductivity and magnetic permeability of the material, which will affect the penetration depth of the eddy current and thus the detection capability of the sensor; defects in the specimen, such as cracks or corrosion, will also affect the distribution of the magnetic field and the signal detected by the coil.

[0046] In addition to the above factors, the number of turns, wire diameter, frequency and impedance matching of the coil will also affect the performance of the sensor.

[0047] The housing 8 of the sensor is generally made of non-magnetic material, and its main function is to protect the coil structure and the magnet 7, without affecting the overall coil structure itself. The position and strength of the magnet 7 in the sensor are usually designed to match the specific application of the overall coil structure during the design phase, so changes in the magnet 7 itself installed in the correct position will not significantly affect the performance of the coil. Therefore, during the packaging process, after the magnet is installed normally, there is no need to perform the impedance measurement and judgment step, and other components can be installed directly.

[0048] Therefore, we can Figure 2 The back plate 5, the receiving coil 2, the exciting coil 4, and the test piece are equivalent to Figure 3 The circuit shown. Among them, L s , L t , L r , L b are the equivalent inductances of the external specimen 6, the excitation coil 4, the receiving coil 2, and the back plate 5; R s , R t , R r , R b are the equivalent resistances of the external specimen 6, the excitation coil 4, the receiving coil 2, and the back plate 5; C t , C r are the equivalent capacitances of the excitation coil 4 and the receiving coil 2 respectively; M ts is the value of the equivalent mutual inductance between the external test piece 6 and the excitation coil 4, M bs is the value of the equivalent mutual inductance between the external specimen 6 and the back plate 5, M tbis the value of the equivalent mutual inductance between the excitation coil 4 and the back plate 5, M tr is the value of the equivalent mutual inductance between the excitation coil 4 and the receiving coil 2; s ,I t ,I r ,I b They are the currents of the external test piece 6, the excitation coil 4, the receiving coil 2 and the back plate 5. The current and equivalent impedance in each loop satisfy the following relationship:

[0049]

[0050] Among them, V t is the input voltage across the excitation coil, j is the imaginary unit in circuit analysis, ω is the angular frequency; the excitation coil 4's own impedance Z t , receiving coil 2 own impedance Z r , backplane 5 equivalent impedance Z b and the equivalent impedance Z of the external specimen 6 s They are:

[0051] Z t =R t +jωL t (2)

[0052]

[0053] Z b =R b +jωj b (4)

[0054] Z s =R s +jωL s (5)

[0055] During the sensor packaging process, there is an influence between the excitation coil 4, the receiving coil 2, the back plate 5 and the external test piece 6. Among them, the number of turns of the excitation coil 4 is small, and the excitation coil 4 is far away from the back plate 5, so the mutual inductance M between the excitation coil 4 and the back plate 5 is ignored. tb , that is, M tb It can be regarded as parasitic coupling and ignored. In addition, the number of turns of the exciting coil 4 is small, and its influence on the receiving coil 2 is also ignored.

[0056] Based on this, during the sensor packaging process, the impedance values ​​that can be measured from both ends of the receiving coil 2 are: the impedance Z of the receiving coil 2 itself r , the real-time impedance Z of the receiving coil 2 when the back plate 5 is installed rb , the real-time impedance Z of the receiving coil 2 when affected by the installed back plate 5 and the external test piece 6 rbs , respectively expressed as follows:

[0057]

[0058] However, the receiving coil 2 has a large number of turns, which has a significant impact on the impedance of the excitation coil 4. Therefore, the impedance values ​​measured from both ends of the excitation coil 4 are: the impedance Z of the excitation coil 4 itself t , the real-time impedance Z of the excitation coil 4 after installing the back plate 5 and the receiving coil 2 trb , the real-time impedance Z of the excitation coil 4 when the back plate 5, the receiving coil 2, and the external test piece 6 exist at the same time trns , respectively expressed as follows:

[0059] Z t =R t +jωL t (9)

[0060]

[0061] According to the above formulas (6) to (11), it can be known that the above M rb 、M rs 、M tr 、M ts and the coupling coefficient k rb , k rs , k tr , k ts Related, Figure 2 The distances h3, h3+h2, h2, and h1 between adjacent components determine the coupling coefficient k. rb , k rs , k tr , k ts It can be further known that by measuring the real-time impedance at both ends of the receiving coil 2 and the exciting coil 4, the reflected impedance of other components can be observed and the influence of other components on the sensor can be determined.

[0062] Therefore, in this embodiment, after the first epoxy sheet 1, the receiving coil 2, the second epoxy sheet 3 and the back plate 5 are sequentially stacked and adhered, the first real-time impedance of the receiving coil 2 is measured, and the first ratio between the first real-time impedance and the design impedance of the receiving coil 2 is obtained, and it is determined whether the first ratio is greater than the preset Pearson correlation coefficient of 0.98: if it is greater than, it indicates that the thickness of the second epoxy sheet 3 between the receiving coil 2 and the back plate 5 meets the design requirements, and the next installation step can be performed; if it is not greater than, it is necessary to adjust the thickness of the second epoxy sheet 3, and adjust the distance between the receiving coil 2 and the back plate 5 in turn, until the first ratio between the first real-time impedance of the receiving coil 2 measured after adjusting the thickness of the second epoxy sheet 3 and the design impedance of the receiving coil 2 is greater than 0.98, and then the next installation step is performed.

[0063] In this embodiment, the thickness of the back plate 5 is greater than 5 times the skin depth. Specifically, the back plate 5 is made of highly conductive metal material, and the design of the back plate 5 above the sensor receiving coil 2 is adjusted according to the sensor operating frequency, so that the thickness of the back plate 5 is greater than 5 times the skin depth, ensuring that within the sensor operating frequency range, the performance of the overall coil structure is no longer affected by other conductive structures (magnets 7) above it, and only the back plate 5 factor needs to be considered. The skin depth refers to the thickness from the conductor surface to the point where the current density drops to 1 / e of the surface current density (approximately equal to 36.8%).

[0064] S2, after sequentially adhering the second epoxy sheet 3 and the excitation coil 4 to the side of the receiving coil 2 away from the first epoxy sheet 1, measures the second real-time impedance of the excitation coil 4, and obtains a second ratio of the second real-time impedance to the design impedance of the excitation coil 4, and determines whether the second ratio is greater than a preset Pearson correlation coefficient: if so, it indicates that the thickness of the second epoxy sheet 3 makes the distance between the excitation coil 4 and the receiving coil 2 meet the design requirements, and the remaining components can be installed, and the remaining components include the housing 8 and the plug 9, etc.; if not, it proves that the thickness of the second epoxy sheet 3 makes the distance between the receiving coil 2 and the excitation coil 4 not meet the design requirements, until the second ratio of the obtained second real-time impedance to the design impedance of the excitation coil 4 is greater than the preset Pearson correlation coefficient, and then the next packaging step is performed;

[0065] After S3 installs the remaining components in sequence, measure the third real-time impedance of the receiving coil 2 and the fourth real-time impedance of the excitation coil 4, and obtain the third ratio between the third real-time impedance and the design impedance of the receiving coil 2, and the fourth ratio between the fourth real-time impedance and the design impedance of the excitation coil 4, and determine whether the third ratio and the fourth ratio are both greater than the preset Pearson correlation coefficient: if both are greater than, adhere an epoxy sheet to the side of the excitation coil 4 away from the receiving coil 2 and package the sensor as a whole; if at least one is not greater than, adjust the installation gap between the remaining components until the third ratio and the fourth ratio meet the requirements, and then adhere a third epoxy sheet 10 to the side of the excitation coil 4 away from the receiving coil 2 and package the sensor as a whole. The final packaging step of the sensor as a whole is not the design focus of this application and will not be repeated here.

[0066] like Figure 4 As shown, it is a schematic diagram of the position structure of an electromagnetic ultrasonic body wave thickness sensor and an external test piece 6 packaged according to the electromagnetic ultrasonic sensor packaging method for impedance monitoring of the present application, from bottom to top are the external test piece 6, the third epoxy sheet 10, the excitation coil 4, the second epoxy sheet 3, the receiving coil 2, the first epoxy sheet 1 and the back plate 5. Figure 5 to Figure 7 As shown, Figure 5 The schematic diagram of the designed impedance measured at both ends of the excitation coil 4 and the receiving coil 2 of the sensor provided in the present application includes the impedance Z of the excitation coil 4 itself. t, the impedance Z of the receiving coil 2 itself r , the real-time impedance Z of the receiving coil 2 after installing the back plate 5 rb , Real-time impedance Z after installing the excitation coil 4 trb After the packaging is completed, the probe is placed on the steel plate specimen (i.e., the external specimen 6 mentioned above) to excite the real-time impedance Z of the coil 4. trbs and the real-time impedance Z of the receiving coil 2 rbs , where the left figure shows the impedance results of the excitation coil 4, and the right figure shows the impedance results of the receiving coil 2. Figure 6 It is a schematic diagram of the impedance at both ends of the excitation coil 4 and the receiving coil 2 after the sensor packaging is completed provided by the present application. Specifically, the left figure in the figure is a schematic diagram of the design impedance value of the sensor excitation coil 4 and the impedance values ​​at both ends of the excitation coil 4 of the other three packaged sensors 1-3, and the right figure is a schematic diagram of the design impedance value of the corresponding sensor receiving coil 2 and the impedance values ​​at both ends of the receiving coil 2 of the sensors 1-3. Figure 7 Schematic diagram of the design signal of the packaged sensor and the detection signal of the three packaged sensors 1 to 3 provided in this application. Figure 7 The signal diagram in shows that the electromagnetic ultrasonic sensor packaging method based on impedance monitoring proposed in the present application has a good effect on ensuring the performance and multi-channel consistency of the electromagnetic ultrasonic sensor, and has practical significance in the sensor packaging process.

[0067] In summary, the present application performs real-time measurement of the impedance at both ends of the installed receiving coil 2 and the excitation coil 4 after each packaging step of the electromagnetic ultrasonic sensor, and calculates the ratio between the real-time impedance of each coil and the corresponding design impedance. By comparing the ratio with the preset Pearson coefficient, it can be determined whether the installation step is qualified, thereby ensuring the consistency between the actual performance of the electromagnetic ultrasonic sensor and the design performance.

[0068] In this embodiment, a swept frequency measurement method is used to measure the aforementioned first real-time impedance, second real-time impedance, third real-time impedance, fourth real-time impedance, the self-impedance of the receiving coil 2 and the self-impedance of the excitation coil 4; specifically, during the swept frequency measurement, the swept frequency range is greater than the operating frequency of the electromagnetic ultrasonic sensor; more specifically, the frequency range of the swept frequency measurement is 20Hz~5MHz, such as 20Hz~2MHz, 30Hz~3MHz, 40Hz~4MHz, 50Hz~5MHz, or the frequency range between any two frequency values ​​in the range of 20Hz~5MHz is used as the swept frequency range, and the number of sampling points during the swept frequency measurement is 400.

[0069] It should be understood that the above-mentioned device is used to execute the method in the above-mentioned embodiment. The implementation principle and technical effect of the corresponding program module in the device are similar to those described in the above-mentioned method. The working process of the device can refer to the corresponding process in the above-mentioned method, which will not be repeated here.

[0070] Based on the method in the above embodiment, an embodiment of the present application provides an electronic device, which may include: a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus. The processor may call the logic instructions in the memory to execute the method in the above embodiment.

[0071] In addition, the logic instructions in the above-mentioned memory can be implemented in the form of software functional units and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application.

[0072] Based on the method in the above embodiment, an embodiment of the present application provides a computer-readable storage medium, which stores a computer program. When the computer program runs on a processor, the processor executes the method in the above embodiment.

[0073] Based on the method in the above embodiment, an embodiment of the present application provides a computer program product. When the computer program product runs on a processor, the processor executes the method in the above embodiment.

[0074] It is understandable that the processor in the embodiment of the present application can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. The general-purpose processor can be a microprocessor or any conventional processor.

[0075] The method steps in the embodiments of the present application can be implemented by hardware or by a processor executing software instructions. The software instructions can be composed of corresponding software modules, and the software modules can be stored in random access memory (RAM), flash memory, read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), registers, hard disks, mobile hard disks, CD-ROMs, or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor so that the processor can read information from the storage medium and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and the storage medium can be located in an ASIC.

[0076] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted through the computer-readable storage medium. The computer instructions may be transmitted from a website site, a computer, a server or a data center to another website site, a computer, a server or a data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or a data center that includes one or more available media integrated. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid state disk (SSD)), etc.

[0077] It should be understood that the various numerical numbers involved in the embodiments of the present application are only used for the convenience of description and are not used to limit the scope of the embodiments of the present application.

[0078] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A method for packaging an electromagnetic ultrasonic sensor based on impedance monitoring, characterized in that: The following steps are involved: S1, after laminating and adhering the back plate (5), the first epoxy sheet (1) and the receiving coil (2) in sequence, measures the first real-time impedance of the receiving coil (2), obtains a first ratio between the first real-time impedance and the design impedance of the receiving coil (2), and determines whether the first ratio is greater than a preset Pearson correlation coefficient: if so, proceeds to the next step of installation; if not, adjusts the thickness of the first epoxy sheet (1) until the first ratio is greater than the preset Pearson correlation coefficient and then proceeds to the next step; S2, after sequentially adhering the second epoxy sheet (3) and the excitation coil (4) to one side of the receiving coil (2), measures the second real-time impedance of the excitation coil (4), obtains a second ratio of the second real-time impedance to the design impedance of the excitation coil (4), and determines whether the second ratio is greater than the preset Pearson correlation coefficient: if so, installs the remaining components; if not, adjusts the thickness of the second epoxy sheet (3) until the second ratio is greater than the preset Pearson correlation coefficient and then proceeds to the next step; S3, after installing the remaining components in sequence, measures the third real-time impedance of the receiving coil (2) and the fourth real-time impedance of the exciting coil (4), and obtains a third ratio between the third real-time impedance and the design impedance of the receiving coil (2), and a fourth ratio between the fourth real-time impedance and the design impedance of the exciting coil (4); determines whether the third ratio and the fourth ratio are both greater than the preset Pearson correlation coefficient: if both are greater than, encapsulates the electromagnetic ultrasonic sensor; if at least one is not greater than, adjusts the installation gap between the remaining components until the third ratio and the fourth ratio meet the requirements and then encapsulates the electromagnetic ultrasonic sensor.

2. The electromagnetic ultrasonic sensor packaging method based on impedance monitoring according to claim 1, characterized in that: Before step S1, the following steps are also performed to screen the receiving coil (2) and the exciting coil (4): The self-impedance of a plurality of candidate receiving coils is detected, and a fifth ratio between the self-impedance of each candidate receiving coil and its designed impedance is obtained, and an alternative receiving coil whose fifth ratio is greater than a preset Pearson correlation coefficient is selected as the receiving coil (2); the self-impedance of a plurality of candidate excitation coils is detected, and a sixth ratio between the self-impedance of each candidate excitation coil and its designed impedance is obtained, and an alternative excitation coil whose sixth ratio is greater than a preset Pearson correlation coefficient is selected as the excitation coil (4).

3. The electromagnetic ultrasonic sensor packaging method based on impedance monitoring according to claim 1, characterized in that: The thickness of the back plate (5) is greater than 5 times the skin depth.

4. The electromagnetic ultrasonic sensor packaging method based on impedance monitoring according to claim 2, characterized in that: The real-time impedances and the self-impedance of the receiving coil (2) and the self-impedance of the exciting coil (4) are measured by a frequency sweeping measurement method.

5. The electromagnetic ultrasonic sensor packaging method based on impedance monitoring as claimed in claim 4, characterized in that: During frequency sweep measurement, the frequency sweep range is greater than the operating frequency of the electromagnetic ultrasonic sensor.

6. The electromagnetic ultrasonic sensor packaging method based on impedance monitoring according to claim 5, characterized in that: The frequency range of the swept frequency measurement is 20Hz~5MHz, and the number of sampling points is 400.

7. The electromagnetic ultrasonic sensor packaging method based on impedance monitoring according to claim 1, characterized in that: The preset Pearson correlation coefficient is 0.

98.

8. The electromagnetic ultrasonic sensor packaging method based on impedance monitoring according to claim 1, characterized in that: In step S3, the remaining components include a housing (8) and a plug (9).

9. An electronic device, characterized in that: include: at least one memory for storing a computer program; At least one processor is used to execute the program stored in the memory. When the program stored in the memory is executed, the processor is used to execute the method according to any one of claims 1 to 8.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program runs on a processor, the processor is caused to execute the method according to any one of claims 1 to 8.

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