Shielding performance detection method and system for printed metal plate

Abstract

The invention discloses a shielding performance detection method and system for a printed metal plate, and relates to the technical field of shielding performance detection. The shielding performance detection method of the printed metal plate comprises the following steps: acquiring a first shielding index; obtaining a second shielding index; acquiring a third shielding index; and obtaining a comprehensive evaluation index. The first group of test data and the first shielding index are obtained through the first test, then the second group of test data and the second shielding index are obtained through the second test, and then the third group of test data and the third shielding index are obtained through the third test. And finally, a comprehensive evaluation index is obtained according to the obtained first shielding index, second shielding index and third shielding index, so that the effect of improving the shielding performance detection accuracy of the printed metal plate is achieved, and the problem of low shielding performance detection accuracy of the printed metal plate in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of shielding performance detection, and in particular to a method and system for detecting the shielding performance of a printed metal plate. Background Art

[0002] With the increasing popularity and complexity of electronic devices, electromagnetic interference (EMI) and radio frequency interference (RFI) are becoming increasingly prominent. These interference sources may come from inside or outside the device, causing serious impact on the normal operation of the device and data transmission. Therefore, improving the shielding performance of electronic equipment has become an important technical requirement. With the continuous advancement of materials science, the emergence of new metal materials and printing technologies has made it possible to improve the shielding performance of printed metal plates. For example, metal materials with high conductivity and high magnetic permeability and precise printing processes can significantly improve the shielding effectiveness of metal plates. In the field of communication equipment, such as mobile phones and base stations, good shielding performance is required to reduce the impact of electromagnetic radiation on the surrounding environment and human body, while ensuring the stable transmission of communication signals. As an important component of electronic equipment, the shielding performance of printed metal plates directly affects the safety and stability of the internal circuits of the equipment. Good shielding performance can effectively isolate external electromagnetic interference and protect the internal circuits of the equipment from damage. With the continuous development of materials science, new metal materials and composite materials will continue to emerge, providing more options for improving the shielding performance of printed metal plates.

[0003] Existing methods for testing the shielding performance of printed metal plates mainly focus on their performance in an electromagnetic environment, that is, their ability to prevent or reduce the propagation of electromagnetic radiation.

[0004] For example, the invention patent announcement with announcement number: CN114660096B discloses a method for testing the thermal neutron shielding performance of a material, which includes: utilizing the characteristic that the neutron absorption cross section of cadmium is very large in the thermal neutron region within 0.5eV, and the cross section decreases sharply when it exceeds 0.5eV, and measuring twice with and without cadmium sheet shielding, to distinguish thermal neutrons with energy below 0.5eV from other neutrons, thereby obtaining the portion of thermal neutron contribution in the detector.

[0005] For example, the radiation protection door shielding performance detection device and method disclosed in the invention patent with announcement number: CN105092609B includes: a Y-axis driving device for driving the radiation source and the radiation detector to move synchronously and parallelly in the Y-axis direction; and an X-axis driving device for driving the radiation protection door to move in the X-axis direction; the Y-axis driving device includes a pulley block and a driving motor, the pulley block is connected to the radiation source and the radiation detector, and the driving motor is connected to any one of the pulleys in the pulley block; the X-axis driving device is a track displacement transmission device.

[0006] However, in the process of implementing the technical solution of the invention in the embodiments of the present application, the present application found that the above technology has at least the following technical problems: In the prior art, since the test frequency when testing the shielding performance of the printed metal plate is uncertain, when the test frequency is too high, the electromagnetic field inside the metal plate may produce a resonance effect, resulting in fluctuations in the shielding effectiveness, while when the test frequency is too low, it may lead to insufficient evaluation of the shielding effectiveness, resulting in the problem of low accuracy in the detection of the shielding performance of the printed metal plate. Summary of the invention

[0007] The embodiments of the present application solve the problem of low accuracy in detecting the shielding performance of printed metal plates in the prior art by providing a method and system for detecting the shielding performance of printed metal plates, thereby improving the accuracy of detecting the shielding performance of printed metal plates.

[0008] An embodiment of the present application provides a method for detecting the shielding performance of a printed metal plate, comprising the following steps: S1, performing a first test on a first group of metal plate samples in a metal plate test group to obtain a first group of test data, and obtaining a first shielding index based on the first group of test data, wherein the first shielding index is used to evaluate the shielding performance of the first group of metal plate samples in a radio frequency electromagnetic field; S2, performing a second test on a second group of metal plate samples in the metal plate test group to obtain a second group of test data, and obtaining a second shielding index based on the second group of test data, wherein the second shielding index is used to evaluate the shielding performance of the second group of metal plate samples in a microwave electromagnetic field; S3, performing a third test on a third group of metal plate samples in the metal plate test group to obtain a third group of test data, and obtaining a third shielding index based on the third group of test data, wherein the third shielding index is used to evaluate the shielding performance of the third group of metal plate samples when isolating external electromagnetic field interference; S4, obtaining a comprehensive evaluation index based on the obtained first shielding index, second shielding index and third shielding index, wherein the comprehensive evaluation index is used to evaluate the comprehensive shielding performance of printed metal.

[0009] Furthermore, a specific method for obtaining the metal plate test group is as follows: screening the metal plates according to a preset metal material to obtain a first metal plate sample; screening the first metal sample according to a preset metal thickness to obtain a second metal plate sample; screening the second metal plate sample according to a preset metal size to obtain a metal plate sample, and dividing the metal plate samples according to a preset ratio to obtain a metal plate test group, wherein the metal plate test group includes a first group of metal plate samples, a second group of metal plate samples and a third group of metal plate samples.

[0010] Furthermore, the specific acquisition process of the first shielding index is as follows: at a preset time point, a first electric field strength and a second electric field strength of a first group of metal plate samples placed in the coaxial transmission line are measured by an electric field strength meter, the first electric field strength represents the electric field strength when the first group of metal plate samples are not in contact with the coaxial transmission line, and the second electric field strength represents the electric field strength when the first group of metal plate samples are in contact with the coaxial transmission line with a preset area; at a preset time point, a first power and a second power of the first group of metal plate samples are measured by a power meter, the first power represents the power when the first group of metal plate samples are not in contact with the coaxial transmission line, and the second power represents the power when the first group of metal plate samples are in contact with the coaxial transmission line with a preset area; a preset first performance threshold, a preset second performance threshold, a preset first weight and a preset second weight are obtained in the database, and the first shielding index is obtained in combination with the first electric field strength, the second electric field strength, the first power and the second power.

[0011] Furthermore, the first shielding index is calculated using the following formula: ; In the formula, represents the first shielding index of the mth metal plate sample in the first group of metal plate samples at the i-th preset time point, , i represents the number of the preset time point, r represents the total number of preset time points, , m represents the number of the metal plate sample in the first group of metal plate samples, n represents the total number of metal plate samples in the first group of metal plate samples, represents the first electric field strength of the mth metal plate sample in the first group of metal plate samples at the i-th preset time point, represents the second electric field strength of the mth metal plate sample in the first group of metal plate samples at the i-th preset time point, represents the first power of the mth metal plate sample in the first group of metal plate samples at the i-th preset time point, represents the second power of the mth metal plate sample in the first group of metal plate samples at the i-th preset time point, Indicates the preset first performance threshold, Indicates the preset second performance threshold, Indicates the preset first weight, represents a preset second weight, and e represents a natural constant.

[0012] Furthermore, the specific process of obtaining the second shielding index is: measuring the incident intensity and transmission intensity of the second group of metal plate samples placed at the preset position of the transmitting and receiving device through a spectrum analyzer at a preset time point, the incident intensity represents the intensity of the incident wave when the second group of metal plate samples are not placed, and the transmission intensity represents the intensity of the transmitted wave when the second group of metal plate samples are placed at the preset position of the transmitting and receiving device; obtaining a preset transmittance threshold in the database, and obtaining the second shielding index in combination with the incident intensity and transmission intensity of the second group of metal plate samples.

[0013] Furthermore, the second shielding index is calculated using the following formula: ; In the formula, represents the second shielding index, represents the incident intensity of the fth metal plate sample in the second group of metal plate samples, , f represents the number of the metal plate sample in the second group of metal plate samples, h represents the total number of metal plate samples in the second group of metal plate samples, represents the transmission intensity of the fth metal plate sample in the second group of metal plate samples, represents the preset transmittance threshold, and e represents a natural constant.

[0014] Furthermore, the specific method of obtaining the third shielding index is as follows: at a preset time point, the angular frequency of the electromagnetic signal of the third group of metal plate samples placed in a preset window of the shielding room is measured by a frequency meter, and the magnetic permeability and electrical conductivity of the third group of metal plate samples are measured by a fluxmeter and a four-probe method respectively, the shielding room is used to isolate the external electromagnetic field, and the third group of metal plate samples are irradiated by the electromagnetic signal emitted outside the preset window; the preset skin depth threshold is obtained in the database, and the third shielding index is obtained in combination with the angular frequency of the electromagnetic signal, the magnetic permeability and electrical conductivity of the third group of metal plate samples.

[0015] Furthermore, the third shielding index is calculated using the following formula: ; In the formula, represents the third shielding index of the mth metal plate sample in the third group of metal plate samples, , m represents the number of the metal plate sample in the third group of metal plate samples, n represents the total number of metal plate samples in the third group of metal plate samples, represents the angular frequency of the electromagnetic signal of the mth metal plate sample in the third group of metal plate samples at the i-th preset time point, , i represents the number of the preset time point, r represents the total number of preset time points, represents the magnetic permeability of the mth metal plate sample in the third group of metal plate samples at the i-th preset time point, represents the conductivity of the mth metal plate sample in the third group of metal plate samples at the i-th preset time point, represents the preset skin depth threshold, and e represents a natural constant.

[0016] Furthermore, the specific acquisition process of the comprehensive evaluation index is as follows: obtaining preset allocation weights from a database, the preset allocation weights including a first allocation weight, a second allocation weight and a third allocation weight; obtaining a comprehensive evaluation index according to the preset allocation weights and the first shielding index, the second shielding index and the third shielding index, and comparing the comprehensive evaluation index with a preset evaluation range. If the comprehensive evaluation index is within the preset evaluation range, the shielding performance of the printed metal plate is judged to be qualified; otherwise, the shielding performance of the printed metal plate is judged to be unqualified.

[0017] The embodiment of the present application provides a shielding performance detection system for a printed metal plate, including: a first shielding index acquisition module, a second shielding index acquisition module, a third shielding index acquisition module and a comprehensive evaluation module; wherein the first shielding index acquisition module is used to perform a first test on a first group of metal plate samples in a metal plate test group to obtain a first group of test data, and obtain a first shielding index according to the first group of test data, and the first shielding index is used to evaluate the shielding performance of the first group of metal plate samples in a radio frequency electromagnetic field; the second shielding index acquisition module is used to perform a second test on a second group of metal plate samples in the metal plate test group to obtain a second group of test data, and obtain a second shielding index according to the second group of test data, and the second shielding index is used to evaluate the shielding performance of the second group of metal plate samples in a microwave electromagnetic field; the third shielding index acquisition module is used to perform a third test on a third group of metal plate samples in the metal plate test group to obtain a third group of test data, and obtain a third shielding index according to the third group of test data, and the third shielding index is used to evaluate the shielding performance of the third group of metal plate samples when isolating external electromagnetic field interference; the comprehensive evaluation module is used to obtain a comprehensive evaluation index according to the obtained first shielding index, second shielding index and third shielding index, and the comprehensive evaluation index is used to evaluate the comprehensive shielding performance of printed metal plates.

[0018] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages: 1. By conducting the first experiment, the second experiment and the third experiment on the metal plate test group respectively, and obtaining the first shielding index, the second shielding index and the third shielding index according to the corresponding experimental data, and obtaining the comprehensive evaluation index according to the obtained first shielding index, the second shielding index and the third shielding index, the numerical evaluation of the shielding performance of the printed metal plate is realized, and then the accuracy of the detection of the shielding performance of the printed metal plate is improved, which effectively solves the problem of low accuracy of the detection of the shielding performance of the printed metal plate in the prior art.

[0019] 2. The first metal plate sample is obtained by screening the metal plates according to the preset metal material, and then the second metal plate sample is obtained by screening the first metal sample according to the preset metal thickness, and then the second metal plate sample is obtained by screening the second metal plate sample according to the preset metal size, and finally the metal plate samples are divided according to the preset ratio to obtain the metal plate test group, thereby improving the accuracy of obtaining the metal plate samples, and further improving the reliability of obtaining the data for evaluating the printed metal plate.

[0020] 3. By obtaining the preset allocation weights from the database, and then obtaining the comprehensive evaluation index based on the preset allocation weights and the first shielding index, the second shielding index and the third shielding index, and finally comparing the comprehensive evaluation index with the preset evaluation range, if the comprehensive evaluation index is within the preset evaluation range, the shielding performance of the printed metal plate is judged to be qualified, otherwise, the shielding performance of the printed metal plate is judged to be unqualified, thereby achieving a comprehensive evaluation of the shielding performance of the printed metal plate, and further achieving an improvement in the effectiveness of evaluating the shielding performance of the printed metal plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A flow chart of a method for detecting shielding performance of a printed metal plate provided in an embodiment of the present application; Figure 2 A statistical diagram of changes in the second shielding index provided in an embodiment of the present application; Figure 3 A schematic structural diagram of a shielding performance detection system for a printed metal plate provided in an embodiment of the present application. DETAILED DESCRIPTION

[0022] The embodiment of the present application solves the problem of low accuracy in detecting the shielding performance of printed metal plates in the prior art by providing a method and system for detecting the shielding performance of printed metal plates. A first test is performed on a first group of metal plate samples in a metal plate test group to obtain a first group of test data and a first shielding index, and then a second test is performed on a second group of metal plate samples in the metal plate test group to obtain a second group of test data and a second shielding index. Then, a third test is performed on a third group of metal plate samples in the metal plate test group to obtain a third group of test data and a third shielding index. Finally, a comprehensive evaluation index is obtained based on the obtained first shielding index, second shielding index and third shielding index, thereby realizing numerical evaluation of the shielding performance of the printed metal plate and improving the accuracy of detecting the shielding performance of the printed metal plate.

[0023] The technical solution in the embodiment of the present application is to solve the problem of low accuracy in detecting the shielding performance of the printed metal plate. The overall idea is as follows: By conducting the first test, the second experiment and the third experiment to obtain the first shielding index, the second shielding index and the third shielding index, a comprehensive evaluation index is obtained based on the obtained data to evaluate the comprehensive shielding performance of the printed metal plate, thereby achieving the effect of improving the accuracy of the detection of the shielding performance of the printed metal plate.

[0024] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0025] like Figure 1As shown, it is a flow chart of a method for detecting the shielding performance of a printed metal plate provided in an embodiment of the present application, the method comprising the following steps: S1, performing a first test on a first group of metal plate samples in a metal plate test group to obtain a first group of test data, and obtaining a first shielding index based on the first group of test data, the first test indicating that the first group of metal plate samples are placed in a radio frequency electromagnetic field for a shielding performance test, and the first shielding index is used to evaluate the shielding performance of the first group of metal plate samples in a radio frequency electromagnetic field; S2, performing a second test on a second group of metal plate samples in the metal plate test group to obtain a second group of test data, and obtaining a second shielding index based on the second group of test data, the second test indicating that the second group of metal plate samples are placed in a microwave electromagnetic field. A shielding performance test is performed, and the second shielding index is used to evaluate the shielding performance of the second group of metal plate samples in the microwave electromagnetic field; S3, a third test is performed on the third group of metal plate samples in the metal plate test group to obtain a third group of test data, and a third shielding index is obtained based on the third group of test data. The third test represents placing the third group of metal plate samples in a first environment for a shielding performance test, and the first environment represents an environment without external electromagnetic interference. The third shielding index is used to evaluate the shielding performance of the third group of metal plate samples when isolating from external electromagnetic field interference; S4, a comprehensive evaluation index is obtained based on the obtained first shielding index, second shielding index and third shielding index, and the comprehensive evaluation index is used to evaluate the comprehensive shielding performance of printed metal.

[0026] In this embodiment, it is ensured that all tests are carried out under the same conditions, including ambient temperature, humidity, electromagnetic field strength, etc., and that all tests are carried out in a controlled environment to reduce the impact of external variables. The size, shape and material properties of each group of metal plate samples are ensured to be consistent through screening to facilitate comparison of performance under different test conditions. In order to verify the reliability of the test results, each test should be repeated multiple times and the reproducibility of the results should be ensured, thereby improving the accuracy of detection of the shielding performance of printed metal plates.

[0027] Furthermore, a specific method for obtaining the metal plate test group is as follows: the metal plates are screened according to a preset metal material to obtain a first metal plate sample, the first metal plate sample represents a metal plate that meets the preset metal material; the first metal sample is screened according to a preset metal thickness to obtain a second metal plate sample, the second metal plate sample represents the first metal sample that meets the preset metal thickness; the second metal plate sample is screened according to a preset metal size to obtain a metal plate sample, and the metal plate samples are divided according to a preset ratio to obtain a metal plate test group, the metal plate test group includes a first group of metal plate samples, a second group of metal plate samples and a third group of metal plate samples.

[0028] In this embodiment, the preset metal material is obtained from a database, the preset metal thickness is represented by the average value obtained after statistical analysis of the printed metal plate data in the database, the preset metal size is represented by the average value obtained after statistical analysis of the printed metal plate data in the database, and the preset ratio is obtained from the database. The preset ratio is generally 3:4:3. Through screening, the variables can be effectively controlled, so that more accurate and reliable results can be obtained in the experiment or production process, thereby improving the accuracy of the test and realizing the improvement of the accuracy of the detection of the shielding performance of the printed metal plate.

[0029] Furthermore, the specific acquisition process of the first shielding index is as follows: at a preset time point, a first electric field strength and a second electric field strength of a first group of metal plate samples placed in the coaxial transmission line are measured by an electric field strength meter, the first electric field strength represents the electric field strength when the first group of metal plate samples are not in contact with the coaxial transmission line, and the second electric field strength represents the electric field strength when the first group of metal plate samples are in contact with the coaxial transmission line with a preset area, and the first group of metal plate samples are irradiated by electromagnetic waves of a preset frequency propagating through the coaxial transmission line; at a preset time point, a first power and a second power of the first group of metal plate samples are measured by a power meter, the first power represents the power when the first group of metal plate samples are not in contact with the coaxial transmission line, and the second power represents the power when the first group of metal plate samples are in contact with the coaxial transmission line with a preset area; a preset first performance threshold, a preset second performance threshold, a preset first weight and a preset second weight are obtained in the database, and the first shielding index is obtained in combination with the first electric field strength, the second electric field strength, the first power and the second power, the preset first weight is used to evaluate the influence of the first electric field strength and the second electric field strength on the first shielding index, and the preset second weight is used to evaluate the influence of the first power and the second power on the first shielding index.

[0030] In this embodiment, the preset frequency electromagnetic wave is obtained from the database, the preset first performance threshold is represented by the result of taking the average value after statistical analysis of the shielding performance data of the printed metal plate in the database, and the preset second performance threshold is represented by the result of taking the average value after statistical analysis of the shielding performance data of the printed metal plate in the database; the coaxial transmission line is a cable, which is composed of an inner conductor, an insulating medium, an outer conductor and an outer sheath. The inner conductor is usually a copper wire, the insulating medium is plastic or other materials, and the outer conductor is a metal tube or a braided mesh, and the outer sheath protects the cable from physical damage. The electric field strength meter is an instrument for measuring the electric field strength, which can measure the strength and direction of the electric field, and is usually composed of a highly sensitive sensor and a signal processing unit. The power meter is an instrument for measuring power, which can measure the power level of the electrical signal, including average power, peak power, etc.; the shielding performance detection accuracy of the printed metal plate is improved.

[0031] Specifically, the preset first weight is obtained from a printed metal plate shielding performance database; in a specific embodiment, a fitting curve is obtained by fitting the relationship between the first shielding index, the first electric field strength and the second electric field strength in a historical period, and the preset first weight corresponding to the input first electric field strength and the second electric field strength is obtained according to the fitting curve.

[0032] Specifically, the preset second weight is obtained from a printed metal plate shielding performance database; in a specific embodiment, a fitting curve is obtained by fitting the relationship between the first shielding index, the first power and the second power within a historical period, and the preset second weight corresponding to the input first power and the second power is obtained according to the fitting curve.

[0033] Furthermore, the first shielding index is calculated using the following formula: ; In the formula, represents the first shielding index of the mth metal plate sample in the first group of metal plate samples at the i-th preset time point, , i represents the number of the preset time point, r represents the total number of preset time points, , m represents the number of the metal plate sample in the first group of metal plate samples, n represents the total number of metal plate samples in the first group of metal plate samples, represents the first electric field strength of the mth metal plate sample in the first group of metal plate samples at the i-th preset time point, represents the second electric field strength of the mth metal plate sample in the first group of metal plate samples at the i-th preset time point, represents the first power of the mth metal plate sample in the first group of metal plate samples at the i-th preset time point, represents the second power of the mth metal plate sample in the first group of metal plate samples at the i-th preset time point, Indicates the preset first performance threshold, Indicates the preset second performance threshold, Indicates the preset first weight, represents a preset second weight, and e represents a natural constant.

[0034] In this embodiment, the algorithm of this embodiment combines the first electric field strength , the second electric field strength , First Power and the second power , the first shielding index of the mth metal plate sample in the first group of metal plate samples at the i-preset time point is obtained through comprehensive analysis. The first electric field strength in this formula is , the second electric field strength , First Power and the second power There is a common regulatory association between them, when the first electric field strength and first power Gradually increases, the second electric field strength and the second power When the first shielding index gradually decreases, it gradually increases. When the numerator in the fraction where the absolute value is located tends to 0, the shielding performance of the first group of metal plate samples in the radio frequency electromagnetic field may deteriorate, and the ability to block electromagnetic wave penetration may be weakened. Therefore, a mathematical form is established for accurate analysis. To simplify the analysis, the first electric field strength The expression is: = ,in, represents the first electric field strength data of the mth metal plate sample in the first group of metal plate samples at the i-th preset time point, represents the reference first electric field strength data of the mth metal plate sample in the first group of metal plate samples at the i-th preset time point, Indicates the reference deviation of the first electric field strength and the second electric field strength The expression is: = ,in, represents the second electric field strength data of the mth metal plate sample in the first group of metal plate samples at the i-th preset time point, represents the reference second electric field strength data of the mth metal plate sample in the first group of metal plate samples at the i-th preset time point, Indicates the second electric field strength reference deviation, the first power The expression is: = ,in, represents the first power data of the mth metal plate sample in the first group of metal plate samples at the i-th preset time point, represents the reference first power data of the mth metal plate sample in the first group of metal plate samples at the i-th preset time point, Indicates the first power reference deviation, the second power The expression is: = ,in, represents the first power data of the mth metal plate sample in the first group of metal plate samples at the i-th preset time point, represents the reference first power data of the mth metal plate sample in the first group of metal plate samples at the i-th preset time point, Indicates the first power reference deviation.

[0035] It should be understood that the first electric field strength data of the mth metal plate sample in the first group of metal plate samples at the i-preset time point is obtained by measurement, the reference first electric field strength data is expressed by analyzing and counting the first electric field strength data of the mth metal plate sample in the first group of metal plate samples at the i-preset time point and taking the average value, the first electric field strength reference deviation is obtained by calculating the first electric field strength data and the reference first electric field strength data through the deviation formula, the second electric field strength data of the mth metal plate sample in the first group of metal plate samples at the i-preset time point is obtained by measurement, the reference second electric field strength data is expressed by analyzing and counting the second electric field strength data of the mth metal plate sample in the first group of metal plate samples at the i-preset time point and taking the average value, the second electric field strength reference deviation is obtained by calculating the second electric field strength data and the reference second electric field strength data through the deviation formula, the mth metal plate sample in the first group of metal plate samples The first power data of the product at the i-th preset time point is obtained by measurement, the reference first power data is represented by the result of analyzing and counting the first power data of the m-th metal plate sample in the first group of metal plate samples at the i-th preset time point and taking the average value, the first power reference deviation is obtained by calculating the first power data and the reference first power data through a deviation formula, the second power data of the m-th metal plate sample in the first group of metal plate samples at the i-th preset time point is obtained by measurement, the reference second power data is represented by the result of analyzing and counting the second power data of the m-th metal plate sample in the first group of metal plate samples at the i-th preset time point and taking the average value, the second power reference deviation is obtained by calculating the second power data and the reference second power data through a deviation formula, the deviation formula is used to measure the difference between the reference value and the actual measurement value, and is represented by the difference between the reference value and the actual measurement value; the shielding performance detection accuracy of the printed metal plate is improved.

[0036] Furthermore, the specific process of obtaining the second shielding index is: at a preset time point, the incident intensity and transmission intensity of the second group of metal plate samples placed at a preset position of the transmitting and receiving device are measured by a spectrum analyzer, the incident intensity represents the intensity of the incident wave when the second group of metal plate samples are not placed, and the transmission intensity represents the intensity of the transmitted wave when the second group of metal plate samples are placed at the preset position of the transmitting and receiving device, the transmitting and receiving device includes a transmitting antenna, a receiving antenna and a signal source, and the second group of metal plate samples are irradiated by a plane wave of a preset frequency transmitted by the transmitting and receiving device; the preset transmittance threshold is obtained in the database, and the second shielding index is obtained in combination with the incident intensity and transmission intensity of the second group of metal plate samples.

[0037] In this embodiment, the preset transmittance threshold is represented by the result of taking the average value after statistical analysis of the shielding performance data of the printed metal plate in the database, and the spectrum analyzer is an electronic test instrument used to measure the spectrum characteristics of the signal. It can display the frequency components of the signal and the amplitude and phase of each component. The transmitting antenna is a device for wireless communication, which converts the electrical signal into electromagnetic waves and radiates them into space. The receiving antenna corresponds to the transmitting antenna, which receives the electromagnetic waves in space and converts them back into electrical signals. The signal source is an electronic device that can generate a specific frequency, amplitude and waveform; the shielding performance detection accuracy of the printed metal plate is improved.

[0038] Furthermore, the second shielding index is calculated using the following formula: ; In the formula, represents the second shielding index, represents the incident intensity of the fth metal plate sample in the second group of metal plate samples, , f represents the number of the metal plate sample in the second group of metal plate samples, h represents the total number of metal plate samples in the second group of metal plate samples, represents the transmission intensity of the fth metal plate sample in the second group of metal plate samples, represents the preset transmittance threshold, and e represents a natural constant.

[0039] In this embodiment, the algorithm of this embodiment combines the incident intensity and transmission intensity , the second shielding index is obtained by comprehensive analysis. In this formula, the incident intensity and transmission intensity There is a common regulatory relationship between them, when the transmission intensity When the incident intensity increases, the second shielding index may increase, but when When it is too large, the second shielding index may decrease. When it is large enough, The smaller it is, the larger the absolute value is, and the smaller the second shielding index is, that is, With the second shield index positively correlated; if the transmittance threshold is preset If the number of hours is sufficient, The smaller the value, the smaller the absolute value, and the larger the second shielding index, that is, and When the numerator in the fraction where the absolute value is located tends to 0, the second shielding index tends to 1, which means that the shielding performance of the second group of metal plate samples in the microwave electromagnetic field is enhanced, that is, it can more effectively block or weaken the propagation of electromagnetic waves, which means that the second group of metal plate samples can provide a higher level of protection when dealing with microwave electromagnetic radiation, reduce the possibility of electromagnetic wave penetration, and thus protect the internal equipment or environment from the influence of electromagnetic interference. Therefore, accurate analysis is carried out by establishing a mathematical form.

[0040] like Figure 2 As shown, it is a statistical diagram of the variation of the second shielding index provided in the embodiment of the present application, wherein it is assumed that: the total number of metal plate samples in the second group of metal plate samples is h=100, and the incident intensity is The range is 500-1000 (w / ), transmission intensity The range is 0-100 (w / ), preset transmittance threshold is 0.5. As can be seen from the figure, as the transmission intensity The gradual increase and incident intensity The second shielding index gradually decreases, which means that the shielding performance of the second group of metal plate samples in the microwave electromagnetic field is weakened, and the possibility of the second group of metal plate samples being penetrated by electromagnetic waves increases; the accuracy of shielding performance detection of printed metal plates is improved.

[0041] Furthermore, the specific method of obtaining the third shielding index is as follows: at a preset time point, the angular frequency of the electromagnetic signal of the third group of metal plate samples placed in a preset window of the shielding room is measured by a frequency meter, and the magnetic permeability and electrical conductivity of the third group of metal plate samples are measured by a fluxmeter and a four-probe method respectively. The shielding room is used to isolate the external electromagnetic field, and the third group of metal plate samples are irradiated by the electromagnetic signal emitted outside the preset window; the preset skin depth threshold is obtained in the database, and the third shielding index is obtained in combination with the angular frequency of the electromagnetic signal, the magnetic permeability and electrical conductivity of the third group of metal plate samples.

[0042] In this embodiment, the preset skin depth threshold is represented by the result of taking the average value after statistical analysis of the shielding performance data of the printed metal plate in the database. The frequency meter usually measures the number of cycles and time intervals of the signal through a counter and a timer to calculate the frequency. Some advanced frequency meters also have a phase measurement function, which can measure the phase difference between two signals. The flux meter usually uses a Hall effect sensor or a magnetoresistive sensor to measure the magnetic field. When the magnetic field passes through the sensor, the sensor generates a voltage or current signal that is proportional to the magnetic field strength, so that the magnetic flux can be calculated. The four-probe method measures conductivity based on the current-voltage relationship. Four probes are arranged on the sample surface at equal intervals, two of which are used to apply current, and the other two probes are used to measure voltage. The conductivity can be calculated based on the measured current and voltage; the shielding performance detection accuracy of the printed metal plate is improved.

[0043] Furthermore, the third shielding index is calculated using the following formula: ; In the formula, represents the third shielding index of the mth metal plate sample in the third group of metal plate samples, , m represents the number of the metal plate sample in the third group of metal plate samples, n represents the total number of metal plate samples in the third group of metal plate samples, represents the angular frequency of the electromagnetic signal of the mth metal plate sample in the third group of metal plate samples at the i-th preset time point, , i represents the number of the preset time point, r represents the total number of preset time points, represents the magnetic permeability of the mth metal plate sample in the third group of metal plate samples at the i-th preset time point, represents the conductivity of the mth metal plate sample in the third group of metal plate samples at the i-th preset time point, represents the preset skin depth threshold, and e represents a natural constant.

[0044] In this embodiment, the algorithm of this embodiment combines the angular frequency , magnetic permeability and conductivity , the third shielding index of the mth metal plate sample in the third group of metal plate samples is obtained through comprehensive analysis. The angular frequency in this formula is , magnetic permeability and conductivity There is a common regulatory relationship between When the preset skin depth threshold If the magnetic permeability is small enough, the third shielding index may increase, but when and conductivity When it decreases to a certain value, the third shielding index may decrease. When the numerator in the fraction where the absolute value is located tends to 0, the third shielding index tends to 1, which means that the shielding performance of the third group of metal plate samples is enhanced when isolating external electromagnetic field interference, indicating that the metal plate has very high absorption and reflection capabilities for electromagnetic waves, which can reduce the interference of electromagnetic waves to the surrounding environment, and also protect the electronic components inside the device from the influence of external electromagnetic fields.

[0045] Assuming r=1, the angular frequency The range is 0-100 (rad / s), the magnetic permeability The range is 1000-5000 (H / m), the conductivity The range is 0-1 (S / m), with a preset skin depth threshold is 0.01(m), then the statistical variation table of the third shielding index is shown in Table 1: Table 1 Statistical changes of the third shielding index

[0046] It can be seen from the table that as the angular frequency The gradual increase of magnetic permeability The gradual increase and conductivity The gradual increase of the third shielding index It gradually increases, which means that under the condition of no external electromagnetic field interference, the electromagnetic shielding effectiveness of the third group of metal plate samples has been significantly improved. This performance enhancement means that the metal plate can effectively block the penetration of electromagnetic waves; the accuracy of shielding performance detection of printed metal plates has been improved.

[0047] Furthermore, the specific process of obtaining the comprehensive evaluation index is as follows: obtaining preset allocation weights from a database, the preset allocation weights including a first allocation weight, a second allocation weight and a third allocation weight, the first allocation weight being used to evaluate the degree of influence of the first shielding index on the comprehensive evaluation index, the second allocation weight being used to evaluate the degree of influence of the second shielding index on the comprehensive evaluation index, and the third allocation weight being used to evaluate the degree of influence of the third shielding index on the comprehensive evaluation index; obtaining the comprehensive evaluation index according to the preset allocation weights and the first shielding index, the second shielding index and the third shielding index, comparing the comprehensive evaluation index with a preset evaluation range, if the comprehensive evaluation index is within the preset evaluation range, then the shielding performance of the printed metal plate is judged to be qualified, otherwise, then the shielding performance of the printed metal plate is judged to be unqualified, wherein the comprehensive evaluation index is the sum of the products of the first shielding index, the second shielding index and the third shielding index and the corresponding first allocation weight, the second allocation weight and the third allocation weight.

[0048] In this embodiment, the first allocation weight is obtained from the printed metal plate shielding performance database, and a fitting curve is obtained by fitting the comprehensive evaluation index and the first shielding index in a historical period to the relationship between the comprehensive evaluation index and the first shielding index, and the first allocation weight corresponding to the input first shielding index is obtained according to the fitting curve; the second allocation weight is obtained from the printed metal plate shielding performance database, and a fitting curve is obtained by fitting the comprehensive evaluation index and the second shielding index in a historical period to the relationship between the comprehensive evaluation index and the second shielding index, and the second allocation weight corresponding to the input second shielding index is obtained according to the fitting curve; the third allocation weight is obtained from the printed metal plate shielding performance database, and a fitting curve is obtained by fitting the comprehensive evaluation index and the third shielding index in a historical period to the relationship between the comprehensive evaluation index and the third shielding index, and the third allocation weight corresponding to the input third shielding index is obtained according to the fitting curve.

[0049] The first shielding index, the second shielding index and the third shielding index respectively evaluate the shielding performance of the printed metal plate under radio frequency, microwave and no external electromagnetic field interference. If the printed metal plate shows excellent shielding performance in the radio frequency electromagnetic field, then it is likely to show good shielding performance in the microwave electromagnetic field, because the wavelength and frequency range of these two electromagnetic fields may be similar, but due to different reflection and absorption capabilities, the shielding performance without external electromagnetic field interference may be better than the shielding performance under radio frequency and microwave conditions. Therefore, it is necessary to assign weights to the three to simultaneously consider their performance in different electromagnetic environments, so as to comprehensively evaluate the shielding performance of the printed metal plate. The first assigned weight represents the importance of the first shielding index in the calculation of the comprehensive evaluation index, the second assigned weight represents the importance of the second shielding index in the calculation of the comprehensive evaluation index, and the third assigned weight represents the importance of the third shielding index in the calculation of the comprehensive evaluation index. By reasonably assigning weights, a complementary effect on the overall evaluation results is formed. Different weights reflect the characteristics of the evaluation object from different angles and aspects, and together constitute a comprehensive and objective evaluation of the evaluation object; the accuracy of the detection of the shielding performance of the printed metal plate is improved.

[0050] like Figure 3As shown, it is a structural schematic diagram of a shielding performance detection system for a printed metal plate provided in an embodiment of the present application. The shielding performance detection system for a printed metal plate provided in an embodiment of the present application includes: a first shielding index acquisition module, a second shielding index acquisition module, a third shielding index acquisition module and a comprehensive evaluation module; wherein the first shielding index acquisition module is used to perform a first test on a first group of metal plate samples in a metal plate test group to obtain a first group of test data, and obtain a first shielding index according to the first group of test data, the first test represents placing the first group of metal plate samples in a radio frequency electromagnetic field for a shielding performance test, and the first shielding index is used to evaluate the shielding performance of the first group of metal plate samples in a radio frequency electromagnetic field; the second shielding index acquisition module is used to perform a second test on a second group of metal plate samples in the metal plate test group to obtain a second group of test data, and obtain a first shielding index according to the second group of test data The data obtains a second shielding index, the second test represents placing the second group of metal plate samples in a microwave electromagnetic field for a shielding performance test, and the second shielding index is used to evaluate the shielding performance of the second group of metal plate samples in the microwave electromagnetic field; the third shielding index acquisition module is used to perform a third test on the third group of metal plate samples in the metal plate test group to obtain a third group of test data, and obtain a third shielding index based on the third group of test data, the third test represents placing the third group of metal plate samples in a first environment for a shielding performance test, the first environment represents an environment without external electromagnetic interference, and the third shielding index is used to evaluate the shielding performance of the third group of metal plate samples when isolating from external electromagnetic field interference; the comprehensive evaluation module is used to obtain a comprehensive evaluation index based on the obtained first shielding index, second shielding index and third shielding index, and the comprehensive evaluation index is used to evaluate the comprehensive shielding performance of printed metal.

[0051] In this embodiment, the first shielding index acquisition module performs a radio frequency electromagnetic field shielding performance test on the first group of metal plate samples in the metal plate test group, the second shielding index acquisition module performs a microwave electromagnetic field shielding performance test on the second group of metal plate samples in the metal plate test group, and the third shielding index acquisition module performs a shielding performance test on the third group of metal plate samples in the metal plate test group. In particular, in an environment without external electromagnetic interference, the comprehensive evaluation module combines the first, second and third shielding indexes to obtain a comprehensive evaluation index, allowing the shielding performance of the metal plate samples to be evaluated from multiple angles and multiple environments, ensuring the comprehensiveness and accuracy of the evaluation results. Through the comprehensive evaluation module, the potential performance of the metal plate samples in practical applications can be more accurately understood; the accuracy of the detection of the shielding performance of the printed metal plate is improved.

[0052] In summary, by conducting the first experiment, the second experiment and the third experiment on the metal plate test group respectively, and obtaining the first shielding index, the second shielding index and the third shielding index according to the corresponding experimental data, and obtaining the comprehensive evaluation index according to the obtained first shielding index, the second shielding index and the third shielding index, thereby realizing the numerical evaluation of the shielding performance of the printed metal plate, and then realizing the improvement of the accuracy of the detection of the shielding performance of the printed metal plate, and effectively solving the problem of low accuracy of the detection of the shielding performance of the printed metal plate in the prior art.

[0053] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0054] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0055] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0056] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0057] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0058] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for detecting shielding performance of a printed metal plate, characterized in that: The following steps are involved: S1, performing a first test on a first group of metal plate samples in a metal plate test group to obtain a first group of test data, and obtaining a first shielding index according to the first group of test data, wherein the first shielding index is used to evaluate the shielding performance of the first group of metal plate samples in a radio frequency electromagnetic field; S2, performing a second test on a second group of metal plate samples in the metal plate test group to obtain a second group of test data, and obtaining a second shielding index according to the second group of test data, wherein the second shielding index is used to evaluate the shielding performance of the second group of metal plate samples in a microwave electromagnetic field; S3, performing a third test on the third group of metal plate samples in the metal plate test group to obtain a third group of test data, and obtaining a third shielding index according to the third group of test data, wherein the third shielding index is used to evaluate the shielding performance of the third group of metal plate samples when isolating external electromagnetic field interference; S4, obtaining a comprehensive evaluation index according to the obtained first shielding index, second shielding index and third shielding index, wherein the comprehensive evaluation index is used to evaluate the comprehensive shielding performance of printed metal.

2. A method for detecting shielding performance of a printed metal plate as claimed in claim 1, characterized in that: The specific method of obtaining the metal plate test group is as follows: Screening the metal plates according to the preset metal material to obtain a first metal plate sample; Screening the first metal sample according to a preset metal thickness to obtain a second metal plate sample; The second metal plate sample is screened according to a preset metal size to obtain a metal plate sample, and the metal plate sample is divided according to a preset ratio to obtain a metal plate test group, wherein the metal plate test group includes a first group of metal plate samples, a second group of metal plate samples and a third group of metal plate samples.

3. A method for detecting shielding performance of a printed metal plate as claimed in claim 1, characterized in that: The specific process of obtaining the first shielding index is as follows: At a preset time point, a first electric field strength and a second electric field strength of a first group of metal plate samples placed in the coaxial transmission line are measured by an electric field strength meter, wherein the first electric field strength represents the electric field strength when the first group of metal plate samples are not in contact with the coaxial transmission line, and the second electric field strength represents the electric field strength when the first group of metal plate samples are in contact with the coaxial transmission line with a preset area; At a preset time point, a first power and a second power of the first group of metal plate samples are measured by a power meter, wherein the first power represents the power when the first group of metal plate samples are not in contact with the coaxial transmission line, and the second power represents the power when the first group of metal plate samples are in contact with the coaxial transmission line with a preset area; A preset first performance threshold, a preset second performance threshold, a preset first weight, and a preset second weight are obtained in a database, and a first shielding index is obtained by combining the first electric field strength, the second electric field strength, the first power, and the second power.

4. A method for detecting shielding performance of a printed metal plate as claimed in claim 3, characterized in that: The first shielding index is calculated using the following formula: ； In the formula, represents the first shielding index of the mth metal plate sample in the first group of metal plate samples at the i-th preset time point, , i represents the number of the preset time point, r represents the total number of preset time points, , m represents the number of the metal plate sample in the first group of metal plate samples, n represents the total number of metal plate samples in the first group of metal plate samples, represents the first electric field strength of the mth metal plate sample in the first group of metal plate samples at the i-th preset time point, represents the second electric field strength of the mth metal plate sample in the first group of metal plate samples at the i-th preset time point, represents the first power of the mth metal plate sample in the first group of metal plate samples at the i-th preset time point, represents the second power of the mth metal plate sample in the first group of metal plate samples at the i-th preset time point, Indicates the preset first performance threshold, Indicates the preset second performance threshold, Indicates the preset first weight, represents a preset second weight, and e represents a natural constant.

5. A method for detecting shielding performance of a printed metal plate as claimed in claim 1, characterized in that: The specific process of obtaining the second shielding index is as follows: At a preset time point, the incident intensity and the transmission intensity of the second group of metal plate samples placed at the preset position of the transmitting and receiving device are measured by a spectrum analyzer, wherein the incident intensity represents the intensity of the incident wave when the second group of metal plate samples are not placed, and the transmission intensity represents the intensity of the transmitted wave when the second group of metal plate samples are placed at the preset position of the transmitting and receiving device; A preset transmittance threshold is obtained from the database, and a second shielding index is obtained by combining the incident intensity and the transmission intensity of the second group of metal plate samples.

6. A method for detecting shielding performance of a printed metal plate as claimed in claim 5, characterized in that: The second shielding index is calculated using the following formula: ； In the formula, represents the second shielding index, represents the incident intensity of the fth metal plate sample in the second group of metal plate samples, , f represents the number of the metal plate sample in the second group of metal plate samples, h represents the total number of metal plate samples in the second group of metal plate samples, represents the transmission intensity of the fth metal plate sample in the second group of metal plate samples, represents a preset transmittance threshold, and e represents a natural constant.

7. A method for detecting shielding performance of a printed metal plate as claimed in claim 1, characterized in that: The specific method of obtaining the third shielding index is as follows: At a preset time point, the angular frequency of the electromagnetic signal of the third group of metal plate samples placed in a preset window of the shielding room is measured by a frequency meter, and the magnetic permeability and electrical conductivity of the third group of metal plate samples are measured by a flux meter and a four-probe method respectively, wherein the shielding room is used to isolate the external electromagnetic field, and the third group of metal plate samples are irradiated by the electromagnetic signal emitted outside the preset window; A preset skin depth threshold is obtained from a database, and a third shielding index is obtained by combining the angular frequency of the electromagnetic signal, the magnetic permeability and the electrical conductivity of the third group of metal plate samples.

8. A method for detecting shielding performance of a printed metal plate as claimed in claim 7, characterized in that: The third shielding index is calculated using the following formula: ； In the formula, represents the third shielding index of the mth metal plate sample in the third group of metal plate samples, , m represents the number of the metal plate sample in the third group of metal plate samples, n represents the total number of metal plate samples in the third group of metal plate samples, represents the angular frequency of the electromagnetic signal of the mth metal plate sample in the third group of metal plate samples at the i-th preset time point, , i represents the number of the preset time point, r represents the total number of preset time points, represents the magnetic permeability of the mth metal plate sample in the third group of metal plate samples at the i-th preset time point, represents the conductivity of the mth metal plate sample in the third group of metal plate samples at the i-th preset time point, represents the preset skin depth threshold, and e represents a natural constant.

9. A method for detecting shielding performance of a printed metal plate as claimed in claim 1, characterized in that: The specific process of obtaining the comprehensive evaluation index is as follows: Acquire preset allocation weights from a database, wherein the preset allocation weights include a first allocation weight, a second allocation weight, and a third allocation weight; A comprehensive evaluation index is obtained according to the preset allocated weight and the first shielding index, the second shielding index and the third shielding index, and the comprehensive evaluation index is compared with the preset evaluation range. If the comprehensive evaluation index is within the preset evaluation range, the shielding performance of the printed metal plate is judged to be qualified; otherwise, the shielding performance of the printed metal plate is judged to be unqualified.

10. A shielding performance detection system for a printed metal plate, characterized in that: include: A first shielding index acquisition module, a second shielding index acquisition module, a third shielding index acquisition module and a comprehensive evaluation module; The first shielding index acquisition module is used to perform a first test on a first group of metal plate samples in the metal plate test group to obtain a first group of test data, and to obtain a first shielding index according to the first group of test data, wherein the first shielding index is used to evaluate the shielding performance of the first group of metal plate samples in a radio frequency electromagnetic field; The second shielding index acquisition module is used to perform a second test on a second group of metal plate samples in the metal plate test group to obtain a second group of test data, and to obtain a second shielding index according to the second group of test data, wherein the second shielding index is used to evaluate the shielding performance of the second group of metal plate samples in a microwave electromagnetic field; The third shielding index acquisition module is used to perform a third test on the third group of metal plate samples in the metal plate test group to obtain a third group of test data, and obtain a third shielding index according to the third group of test data, wherein the third shielding index is used to evaluate the shielding performance of the third group of metal plate samples when isolating external electromagnetic field interference; The comprehensive evaluation module is used to obtain a comprehensive evaluation index according to the obtained first shielding index, second shielding index and third shielding index, and the comprehensive evaluation index is used to evaluate the comprehensive shielding performance of printed metal.

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