A battery cover NCVM coating detection method and device

Abstract

The present application discloses a method and device for detecting NCVM coating on a battery cover. The device may include: a radio frequency signal module, a transmitting antenna, a receiving antenna, a power meter module, and a control module, wherein: the radio frequency signal module is coupled to the transmitting antenna and the control module respectively, the power meter module is coupled to the receiving antenna and the control module respectively, and the transmitting antenna and / or the receiving antenna are in close contact with the battery cover; the control module is used to control the radio frequency signal module to excite the transmitting antenna to transmit a first signal, the power of the first signal being a first threshold and the frequency of the first signal being a second threshold; the receiving antenna is used to receive a second signal, the second signal being a signal of the first signal passing through the battery cover; the power meter module is used to detect the power value of the second signal; and the control module is further used to determine whether the NCVM coating on the battery cover is normal based on the power value and a third threshold. The present application embodiment can improve the versatility of NCVM coating detection.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of terminal technology, and more particularly to a method and device for detecting a coating of a battery cover using non-conductor metal vapor metallization (NCVM) technology. Background Art

[0002] With the rapid development and popularization of smart terminals, consumers have increasingly higher requirements for the appearance of smart terminals. At present, the battery covers of mainstream smart terminals such as mobile phones or tablets on the market all have a metallic color effect. This metallic color effect is achieved through the NCVM coating process. The NCVM coating process is a non-conductive electroplating technology. The key technology of this process is to coat the mobile phone battery cover with a thin layer of metal through vacuum sputtering. This metal layer is called NCVM coating. Under normal circumstances, the NCVM coating does not have conductive properties. However, if the vacuum sputtering process of the NCVM coating process is not properly controlled, the NCVM coating may become too thick and produce conductive properties, affecting the radiation characteristics of the mobile phone antenna. Therefore, after the battery cover is manufactured, the manufacturer needs to test whether the NCVM coating is normal.

[0003] Currently, the non-metallic layer on the battery cover must be scraped off to expose the metal layer (i.e., the NCVM coating). Only then can the on-resistance of the NCVM coating be measured to verify its integrity. However, this approach causes irreversible physical damage to the battery cover. Summary of the Invention

[0004] The embodiments of the present application disclose a battery cover NCVM coating detection device, which is used to improve the versatility of battery cover NCVM coating detection.

[0005] The first aspect discloses a battery cover NCVM coating detection device, which may include a radio frequency signal module, a transmitting antenna, a receiving antenna, a power meter module and a control module, wherein: the radio frequency signal module is respectively coupled to the transmitting antenna and the control module, the power meter module is respectively coupled to the receiving antenna and the control module, and the transmitting antenna and / or the receiving antenna is close to the battery cover; the control module is used to control the radio frequency signal module to excite the transmitting antenna to transmit a first signal, the power of the first signal is a first threshold, and the frequency of the first signal is a second threshold; the receiving antenna is used to receive a second signal, and the second signal is a signal of the first signal passing through the battery cover; the power meter module is used to detect the power value of the second signal; the control module is also used to determine whether the NCVM coating of the battery cover is normal based on the power value and the third threshold.

[0006] In this embodiment of the present application, since the power of the same signal after transmission through NCVM coatings of different thicknesses varies, and abnormal NCVM coatings are often thicker than normal NCVM coatings, the control module can compare the power of the second signal received by the receiving antenna with a third threshold value to determine whether the thickness of the battery cover NCVM coating is normal. Since the non-metallic layer on the battery cover surface does not need to be scraped off before testing, damage to the battery cover is avoided, thereby improving the versatility of battery cover NCVM coating testing. Furthermore, since the non-metallic layer on the battery cover surface does not need to be scraped off, the complexity of the testing steps can be reduced, thereby improving testing efficiency. Furthermore, since no physical damage is caused to the battery cover, all battery covers can be tested without omissions, thereby ensuring the accuracy of the test results. Current battery cover NCVM coating testing requires different test fixtures for different battery cover types. However, in this embodiment of the present application, NCVM coating testing can be performed directly on the battery cover, regardless of the battery cover type. This ensures the versatility of battery cover NCVM coating testing. In addition, for different types of battery covers, the control module can adapt to the detection of different types of battery covers by adjusting the first threshold, the second threshold and the third threshold, thereby avoiding the production of more fixtures and improving the applicability of the solution.

[0007] As a possible implementation manner, the control module controls the RF signal module to excite the transmitting antenna to transmit the first signal, including: the control module is used to send a control signal to the RF signal module, the control signal including the first threshold and the second threshold; the RF signal module is used to generate a first signal based on the first threshold and the second threshold; the transmitting antenna is used to transmit the first signal.

[0008] In the embodiment of the present application, currently, different types of battery cover NCVM coating detection require the production of different test fixtures, and in the embodiment of the present application, the control module can adjust the transmission power (first threshold) of the first signal, the frequency (second threshold) of the first signal, and the third threshold through the control signal to adapt to the detection of different types of battery covers. Therefore, compared to remaking the test fixture, the preparatory operations before the test can be reduced, thereby speeding up the detection progress and providing the versatility of the test. In addition, the control module can determine the power and frequency of the first signal through the control information to ensure the uniformity of the power and frequency during the verification process, thereby ensuring the validity and rationality of the verification results.

[0009] As a possible implementation manner, the transmitting antenna and / or the receiving antenna are located on both sides of the battery cover.

[0010] In the embodiments of the present application, the loss of the first signal passing through an abnormal NVCM coating is more severe than that of a normal NCVM coating. Therefore, the transceiver antennas can be placed on both sides of the battery cover, with at least one antenna positioned in close proximity to the battery cover. This significantly changes the signal power passing through the abnormal NCVM coating on the battery cover, making it easier to determine whether the NCVM coating is normal based on the power of the received signal. Furthermore, this simple antenna placement method avoids irreversible damage to the battery cover and facilitates placement and removal of the battery cover, making it suitable for testing NCVM coatings on most types of battery covers. This improves the flexibility and operability of the test.

[0011] As a possible implementation manner, the transmitting antenna and the receiving antenna are located on the same side of the battery cover.

[0012] In the embodiment of the present application, since the shape of the battery cover is generally sheet-like, and it is difficult for the signal to propagate through the abnormal NCVM coating (that is, relative to the normal NCVM coating, the signal loss through the abnormal NCVM coating is larger). Therefore, the transceiver antenna can be placed on the same side of the battery cover, and the transceiver antenna can be close to the battery cover. The signal power value passing through the abnormal battery cover NCVM coating is significantly different from that of the normal NCVM coating, so that it is easier to judge whether the above-mentioned NCVM coating is normal based on the power value of the received signal (second signal), thereby improving the detection effect. In addition, since the placement method of this battery cover is relatively simple, the operation of the detection process can be made more convenient and quick, thereby improving the detection efficiency. And this solution can also adapt to the detection of most types of battery cover NCVM, and has good applicability.

[0013] As a possible implementation manner, the control module determines whether the NCVM coating of the battery cover is normal based on the power value and the third threshold, including: when the absolute value of the difference between the power value and the third threshold is less than a fourth threshold, determining that the NCVM coating is normal.

[0014] In the embodiments of the present application, compared to the current method of testing the reflection coefficient using a vector network analyzer to determine whether the NCVM coating on a battery cover is normal, this solution utilizes the antenna's coupling and loading effects to significantly differ the power values ​​received by the signal passing through a normal NCVM coating and an abnormal NCVM coating. This can significantly increase the difference between the power value of the received signal and a third threshold, thereby clearly distinguishing the NCVM coating on a normal battery cover from that on an abnormal battery cover, thereby improving detection effectiveness. Furthermore, since vector network analyzers are relatively expensive to use, this solution eliminates the need for a vector network analyzer to test the power value of the received signal, thus saving costs.

[0015] As a possible implementation manner, the control module determines whether the NCVM coating of the battery cover is normal based on the power value and the third threshold value, and further includes: when the absolute value of the difference between the power value and the third threshold value is greater than or equal to a fourth threshold value, determining that the NCVM coating is abnormal.

[0016] In the embodiments of the present application, compared to the current method of testing the reflection coefficient using a vector network analyzer to determine whether the NCVM coating on a battery cover is normal, this solution utilizes the antenna's coupling and loading effects to significantly differ the power values ​​received by the signal passing through a normal NCVM coating and an abnormal NCVM coating. This significantly increases the difference between the power value of the received signal and a third threshold, thereby clearly distinguishing between the NCVM coating on a normal battery cover and the NCVM coating on an abnormal battery cover, thereby improving detection effectiveness. Furthermore, since vector network analyzers are relatively expensive to use, this solution does not require one to test the power value of the received signal, thus saving costs.

[0017] As a possible implementation manner, the control module is also used to display the detection result of the NCVM coating.

[0018] In the embodiment of the present application, the control module can display the detection results of the NCVM coating, which can facilitate the operation and improvement of the detection personnel, thereby improving the user experience of the above-mentioned detection device.

[0019] The second aspect discloses a battery cover NCVM coating detection method, which is applied to a battery cover NCVM coating detection device, the device including a radio frequency signal module, a transmitting antenna, a receiving antenna, a power meter module and a control module. The method may include: controlling the radio frequency signal module through the control module to excite the transmitting antenna to transmit a first signal, the power of the first signal is a first threshold, and the frequency of the first signal is a second threshold; receiving a second signal through the receiving antenna, the second signal being a signal of the first signal passing through the battery cover; detecting the power value of the second signal through the power meter module; and determining whether the NCVM coating of the battery cover is normal based on the power value and a third threshold through the control module.

[0020] In this embodiment of the present application, since the power of the same signal after transmission through NCVM coatings of different thicknesses varies, and abnormal NCVM coatings are often thicker than normal NCVM coatings, the control module can compare the power of the second signal received by the receiving antenna with a third threshold value to determine whether the thickness of the battery cover NCVM coating is normal. Since the non-metallic layer on the battery cover surface does not need to be scraped off before testing, damage to the battery cover is avoided, thereby improving the versatility of battery cover NCVM coating testing. Furthermore, since the non-metallic layer on the battery cover surface does not need to be scraped off, the complexity of the testing steps can be reduced, thereby improving testing efficiency. Furthermore, since no physical damage is caused to the battery cover, all battery covers can be tested without omissions, thereby ensuring the accuracy of the test results. Current battery cover NCVM coating testing requires different test fixtures for different battery cover types. However, in this embodiment of the present application, NCVM coating testing can be performed directly on the battery cover, regardless of the battery cover type. This ensures the versatility of battery cover NCVM coating testing. In addition, for different types of battery covers, the control module can adapt to the detection of different types of battery covers by adjusting the first threshold, the second threshold and the third threshold, thereby avoiding the production of more fixtures and improving the applicability of the solution.

[0021] As a possible implementation manner, determining whether the NCVM coating of the battery cover is normal based on the power value and the third threshold by the control module includes: when the absolute value of the difference between the power value and the third threshold is less than a fourth threshold, determining that the NCVM coating is normal by the control module.

[0022] As a possible implementation manner, determining whether the NCVM coating of the battery cover is normal based on the power value and the third threshold by the control module also includes: when the absolute value of the difference between the power value and the third threshold is greater than or equal to a fourth threshold, determining that the NCVM coating is abnormal by the control module.

[0023] As a possible implementation, the method may further include: displaying the detection result of the NCVM coating by the control module.

[0024] The beneficial effects in the second aspect are the same as those described in the first aspect above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of a mobile phone battery cover disclosed in an embodiment of the present application;

[0026] Figure 2This is a schematic structural diagram of a battery cover coating disclosed in an embodiment of the present application;

[0027] Figure 3 This is a schematic structural diagram of a battery cover NCVM coating detection device disclosed in an embodiment of the present application;

[0028] Figure 4 This is a schematic structural diagram of another battery cover NCVM coating detection device disclosed in an embodiment of the present application;

[0029] Figure 5 This is a schematic structural diagram of another battery cover NCVM coating detection device disclosed in an embodiment of the present application;

[0030] Figure 6 1 is a schematic diagram of a battery cover NCVM coating detection device disclosed in an embodiment of the present application;

[0031] Figure 7 Schematic diagram of a battery cover NCVM coating detection operation disclosed in an embodiment of the present application;

[0032] Figure 8 This is a flow chart of a battery cover NCVM coating detection method disclosed in an embodiment of the present application;

[0033] Figure 9 is a schematic diagram of a scattering coefficient curve disclosed in an embodiment of the present application;

[0034] Figure 10 This is a flow chart of comparison and analysis of S parameter determination disclosed in an embodiment of the present application;

[0035] Figure 11 This is a flow chart of comparison and analysis of power determination disclosed in an embodiment of the present application;

[0036] Figure 12 This is a schematic diagram of a device for detecting NCVM coating on a battery cover with an FPC antenna disclosed in an embodiment of the present application;

[0037] Figure 13 This is a schematic diagram of a simulation model for detecting NCVM coating on a battery cover disclosed in an embodiment of the present application;

[0038] Figure 14 This is a schematic diagram of simulation results of a battery cover NCVM coating detection disclosed in an embodiment of the present application. DETAILED DESCRIPTION

[0039] The present application discloses a method and device for detecting the NCVM coating on a battery cover, which are used to ensure the versatility of the method and device. Detailed descriptions are given below.

[0040] In order to better understand the battery cover NCVM coating detection method and device disclosed in the embodiment of the present application, the relevant technologies of the embodiment of the present application are first introduced below.

[0041] In order to pursue the beauty of smart terminals, many of them have metal color on their battery covers. Such as smart phones, tablet computers and other smart terminals. Figure 1 , Figure 1 Schematic diagram of a mobile phone battery cover disclosed in the embodiment of this application. Figure 1 As shown, the mobile phone battery cover can be separated from the mobile phone body (ie, the body part), and the outer side of the mobile phone battery cover can be plated with a coating that makes it show a metallic color effect.

[0042] See also Figure 2 , Figure 2 This is a schematic diagram of the structure of a battery cover coating disclosed in an embodiment of the present application. Figure 2 As shown, the battery cover coating typically consists of three layers: a top non-metallic layer, a middle NCVM coating (i.e., a metal layer), and a bottom layer. The bottom layer covers the battery cover glass layer. The coating is generally about 0.1 mm thick.

[0043] NCVM coating is achieved through the NCVM coating process, a non-conductive electroplating technology. The key to this process is vacuum sputtering, which deposits a thin metal layer on the battery cover. This metal layer is the NCVM coating. The NCVM process can be divided into five main steps: 1. Surface cleaning (to remove dirt and activate the surface); 2. Ultraviolet (UV) primer (to adhere the vacuum metallization (VM) layer); 3. Metal sputtering; 4. UV intermediate coating (to cure and stabilize the metal layer); and 5. UV topcoat (to enhance strength). During the vacuum sputtering process, variations in one or more steps within the NCVM process can result in varying thicknesses of the NCVM coating on different battery covers. A thicker NCVM coating has lower resistance and better conductivity, which can affect the radiation characteristics of the smart device antenna. Therefore, in order to ensure that the thickness of the battery cover NCVM coating is reasonable, that is, to ensure that the battery cover NCVM coating is normal, it is necessary to test the battery cover NCVM coating. The radiation characteristics may include the energy and radiation pattern of the antenna radiated into space.

[0044] In one case, since the NCVM coating on the battery cover is located on the inner layer of the battery cover, during sampling inspection, it is necessary to scrape off the non-metallic layer on the surface of the battery cover to expose the NCVM coating. The resistance of the NCVM coating can then be measured. Since resistance is inversely proportional to thickness, when the NCVM coating is thicker, the resistance of the NCVM coating is lower, and when the NCVM coating is thinner, the resistance of the NCVM coating is higher. Therefore, by measuring the resistance of the NCVM coating, the approximate thickness of the NCVM coating can be determined, and thus whether the NCVM coating is normal.

[0045] The above method requires scraping the surface of the battery cover, which damages the coating. Since this damage is irreversible, it has limited applicability. Furthermore, due to the irreversible nature of the damage, only a sampling of battery covers can be inspected, not all of them, which creates the risk of missing a sample and reduces its versatility. Furthermore, since scraping the surface of the battery cover is required for random inspection, the operation is complex, reducing detection efficiency.

[0046] In another case, different test fixtures are needed to test the NCVM coating on different types of battery covers. The test fixture can have multiple test probes, which are used to contact different locations on the battery cover surface and can send and receive signals to the battery cover. The vector network analyzer can collect the transmitted and reflected signals through the test probes to determine the reflection curve of the battery cover. In this case, the battery cover can be treated as a passive single-port device. As the thickness of the NCVM coating on the battery cover increases, its resistance decreases. Therefore, the conduction loss inside the battery cover increases, causing the reflection curve measured by the test probe to deviate from the normal reflection curve. Therefore, the normality of the NCVM coating on the battery cover can be determined by comparing the measured reflection curve with the normal reflection curve.

[0047] Because different test fixtures must be made for different types of battery covers, the number of test fixtures required is too large to be used for all types of battery covers, reducing versatility. Furthermore, vector network analyzers are expensive and their use costs are high.

[0048] In summary, existing battery cover NCVM coating inspection processes present issues such as damage to the battery cover, missed inspections, a lack of universality, high costs due to expensive components, and low efficiency due to complex inspection operations. Therefore, improving the universality of battery cover NCVM coating inspection is an urgent issue.

[0049] See also Figure 3 , Figure 3This is a schematic diagram of the structure of a battery cover NCVM coating detection device disclosed in an embodiment of the present application. Figure 3 As shown, the battery cover NCVM coating detection device may include a radio frequency signal module 301, a transmitting antenna 302, a receiving antenna 303, a power meter module 304 and a control module 305, wherein:

[0050] The radio frequency signal module 301 is coupled to the transmitting antenna 302 and the control module 305 respectively, and the power meter module 304 is coupled to the receiving antenna 303 and the control module 305 respectively. The transmitting antenna 302 and / or the receiving antenna 303 is close to the battery cover;

[0051] A control module 305 is configured to control the radio frequency signal module 301 to excite the transmitting antenna 302 to transmit a first signal, where the power of the first signal is a first threshold and the frequency of the first signal is a second threshold;

[0052] A receiving antenna 303 is used to receive a second signal, where the second signal is a signal of the first signal passing through the battery cover;

[0053] A power meter module 304 is configured to detect a power value of the second signal;

[0054] The control module 305 is further configured to determine whether the NCVM coating of the battery cover is normal according to the power value and the third threshold value.

[0055] The transmitting antenna 302 can be a microstrip antenna, a monopole antenna, or other antenna capable of transmitting wireless signals. The radio frequency signal module 301 can be a wireless radio frequency (RF) signal source, and the RF signal source can be a phase-locked loop chip module that generates radio frequency signals. The transmitting antenna 302 and the radio frequency signal module 301 can be connected via a wired line, for example, via a coaxial line. The radio frequency signal module 301 can provide an excitation signal to the transmitting antenna 302 according to the control module 305. After receiving the excitation signal from the radio frequency signal module 301, the transmitting antenna 302 can transmit a first signal. The first signal is a wireless radio frequency signal, and the excitation signal can be the same as the first signal.

[0056] The receiving antenna 303 can be a microstrip antenna, a monopole antenna, or other antenna capable of receiving wireless signals. The power meter module 304 can be a simple power meter capable of detecting the power value of a radio frequency signal. For example, the power meter module 304 can be a radio frequency detection chip module. The receiving antenna 303 and the power meter can be connected via a wired line, for example, via a coaxial line. After the receiving antenna 303 receives the second signal passing through the NCVM coating of the battery cover, the power meter module 304 can detect the power value of the second signal. The second signal is the signal after the first signal passes through the NCVM coating of the battery cover, that is, the signal received by the receiving antenna 303 after the first signal passes through the NCVM coating of the battery cover.

[0057] The above-mentioned battery cover can be placed between the transmitting antenna 302 and the receiving antenna 303, and at least one of the transmitting antenna 302 and the receiving antenna 303 is in close contact with the above-mentioned battery cover, that is, the transmitting antenna 302 can be placed in close contact with the battery cover, and the receiving antenna 303 can be placed separately from the battery cover; the transmitting antenna 302 can be placed separately from the battery cover, and the receiving antenna 303 can be placed in close contact with the battery cover; or the transmitting antenna 302 can be placed in close contact with the battery cover, and the receiving antenna 303 can be placed in close contact with the battery cover.

[0058] The control module 305 can control the RF signal module 301 to excite the transmitting antenna 302 to transmit a first signal, wherein the power of the first signal can be a first threshold, and the frequency of the first signal can be a second threshold. In other words, it can be understood that the control module 305 can control the power and frequency of the first signal.

[0059] After detecting the power value of the second signal, the power meter module 304 may send the power value to the control module 305. The control module 305 may receive the power value from the power meter module 304 and then determine whether the NCVM coating of the battery cover is normal based on the power value and the third threshold.

[0060] In one embodiment, the control module 305 controls the RF signal module 301 to excite the transmitting antenna 302 to transmit the first signal, including:

[0061] A control module 305 is configured to send a control signal to the RF signal module 301, where the control signal includes a first threshold and a second threshold;

[0062] The radio frequency signal module 301 is configured to generate a first signal according to a first threshold and a second threshold;

[0063] The transmitting antenna 302 is configured to transmit a first signal.

[0064] The control module 305 can first determine a control signal and then send the control signal to the RF signal module 301. The control signal can include a first threshold and a second threshold, and the control signal can be a digital signal. The control module 305 can first determine the first threshold and the second threshold, where the first threshold can represent the power of the first signal and the second threshold can represent the frequency of the first signal. The control signal can then be determined based on the first and second thresholds. Specifically, before detecting a certain type of battery cover, the control module 305 can first determine the first and second thresholds. Preferably, the first threshold can be the center frequency of the transmitting antenna 302. Once the first and second thresholds for a certain type of battery cover are determined, they will not change during the battery cover detection process. It should be understood that the first and second thresholds are determined in advance through extensive experimentation and analysis. Since the first and second thresholds may differ for different types of battery covers, the power and frequency of the first signal can be determined before measuring the NCVM coating of a certain type of battery cover. It should be understood that the power and frequency of the first signal should be determined to best distinguish between normal and abnormal NCVM coatings for the current type of battery.

[0065] After receiving the control signal from the control module 305 , the RF signal module 301 may generate a first signal having a transmission power of a first threshold and a frequency of a second threshold.

[0066] In one embodiment, when the absolute value of the difference between the power value and the third threshold value is less than a fourth threshold value, it is determined that the NCVM coating is normal.

[0067] In one embodiment, when the absolute value of the difference between the power value and the third threshold is greater than or equal to a fourth threshold, it is determined that the NCVM coating is abnormal.

[0068] After the control module 305 receives the power value x of the second signal from the power meter module 304, the absolute value of the difference between the power value x and the third threshold value a can be compared with the fourth threshold value b to determine whether the NCVM coating is normal. Specifically, when the absolute value of the difference between the power value x and the third threshold value a is less than the fourth threshold value b (i.e., |xa|<), it can be determined that the NCVM coating is normal. When the absolute value of the difference between the power value and the third threshold value is greater than or equal to the fourth threshold value (i.e., |xa|≥b), it can be determined that the NCVM coating is abnormal. Among them, the third threshold value can be determined based on the power value of the second signal detected by the first signal through the normal NCVM coating in the current type of battery cover. The fourth threshold value can be understood as the range size that can determine that the current battery cover NCVM coating is normal, and can also be understood as the tolerance range of the normal battery cover NCVM coating. The control module 305 can collect power value data of battery covers with normal and abnormal NCVM coatings, and determine the third threshold value and the fourth threshold value based on the collected power value data.

[0069] The third threshold value can be calculated by the control module 305 or manually input. In one case, when the power of the first signal is determined to be the first threshold value and the frequency of the first signal is determined to be the second threshold value (i.e., when the first threshold value and the second threshold value are determined), after the first signal passes through a certain type of normal battery cover NCVM coating, the third threshold value can be determined based on the power value of the second signal passing through the normal NCVM coating. For example, the power value of the second signal can be measured for multiple (the more the better) different normal NCVM coatings, and the average value of these multiple power values ​​is determined as the third threshold value. In another case, since the size of the third threshold value can be determined after a large number of experiments, the user can directly input it.

[0070] The fourth threshold value can be variable or fixed. Since different types of battery covers may have different evaluation criteria, the fourth threshold value can be adjusted for each type of battery cover. The fourth threshold value for a particular type of battery cover can be fixed, i.e., when the type of battery cover is determined, the corresponding fourth threshold value is also determined. It should be understood that the fourth threshold values ​​for different types of battery covers can be the same or different.

[0071] It should be noted that the initial first threshold, second threshold, third threshold, and fourth threshold can be determined first, and then the NCVM coating of the battery cover with known results can be tested. When there is a deviation in the test result, the value of at least one of the first threshold, second threshold, third threshold, and fourth threshold can be adjusted until the accuracy of the test result reaches a certain value. The first threshold, second threshold, third threshold, and fourth threshold at this time can then be determined as the first threshold, second threshold, third threshold, and fourth threshold corresponding to this type of battery cover. For example, when it is necessary to test a new type of battery cover, the test results of multiple battery covers of this new type can be determined first. Then, these battery covers can be tested based on the current first threshold, second threshold, third threshold, and fourth threshold, so that the accuracy of the test results of the current first threshold, second threshold, third threshold, and fourth threshold can be determined. When the accuracy rate cannot reach a certain value, the first, second, third, and fourth thresholds can be adjusted to adapt to the detection of this new type of battery cover. When the accuracy rate of the detection result can reach a certain value, the first, second, third, and fourth thresholds at this time can be determined as the first, second, third, and fourth thresholds used when detecting the NCVM coating of this new type of battery cover. In this way, the first, second, third, and fourth thresholds can be adaptively adjusted to ensure the accuracy of the detection results. Preferably, the control module 305 can prioritize adjusting the fourth threshold to adapt to the type of battery cover. It should be understood that the above adjustment of the first, second, third, and fourth thresholds is completed before detecting the NCVM coating of the battery cover. Once the first, second, third, and fourth thresholds for a certain battery cover type are determined, they will not be adjusted during the battery cover NCVM coating detection process.

[0072] The theoretical basis of the above-mentioned battery cover NCVM coating detection device is described below.

[0073] Radio wave propagation theory shows that when a space electromagnetic wave is perpendicularly incident on the surface of an ideal conductor, total internal reflection occurs. When the NCVM coating is too thick (abnormal), it can behave like a conductor with finite thickness and finite conductivity. Therefore, when a space electromagnetic wave is incident on the abnormal NCVM coating, there is some reflection, but not necessarily total reflection. Conversely, when a space electromagnetic wave is incident on a normal NCVM coating, there is no reflection, or very little reflection. Therefore, fewer space electromagnetic waves pass through the abnormal NCVM coating, while more pass through the normal NCVM coating. Furthermore, when an electromagnetic wave of the same power and frequency is transmitted through the abnormal NCVM coating, the received electromagnetic wave has a smaller power value; conversely, when it passes through the normal NCVM coating, the received electromagnetic wave has a larger power value. Because the power values ​​of the space electromagnetic wave passing through the normal and abnormal NCVM coatings differ significantly, the accuracy of the detection results can be guaranteed.

[0074] The skin effect refers to the phenomenon in which, when alternating current or an alternating electromagnetic field flows through a conductor, the current distribution within the conductor becomes uneven, concentrating on the conductor's "skin." This means that the current is concentrated in a thin layer on the conductor's outer surface. The closer to the surface, the greater the current density, while the actual current inside the conductor is relatively low. This results in increased resistance and power loss in the conductor. Because the skin effect occurs when electromagnetic waves strike the surface of a conductor, and the skin effect becomes more pronounced with higher frequencies, some of the energy is distributed on the conductor's surface, creating a certain skin depth (the depth at which the current is concentrated on the conductor's surface). Therefore, when the conductor is thick, electromagnetic waves have difficulty penetrating it. When an NCVM coating is in the propagation path of electromagnetic waves, electromagnetic waves can penetrate normal NCVM coatings, while abnormal NCVM coatings cannot. Consequently, the abnormal NCVM coating receives less electromagnetic wave power than the normal NCVM coating.

[0075] The Friis transmission formula is Among them, P r is the power of the receiving antenna, P t is the power of the transmitting antenna, G t is the transmitting antenna gain, G ris the receiving antenna gain, λ is the wavelength of the electromagnetic wave, and R is the transmission distance, i.e., the distance between the transmitting and receiving antennas. Therefore, electromagnetic waves propagating in space attenuate inversely proportional to the square of the distance. Regarding antenna transmission and reception, the energy emitted by the transmitting antenna is affected by multipath attenuation and reflection. When an abnormal battery cover NCVM coating is located in the transmission path of the transceiver antenna, significant attenuation and reflection occur along the propagation path, significantly reducing the power of the second signal received by the receiving antenna 303. This effectively distinguishes between normal and abnormal battery cover NCVM coatings.

[0076] The electromagnetic field generated by an antenna is primarily divided into the near-field and far-field regions. The areas outside the antenna radiator can be classified as the near-field and far-field regions, respectively, from near to far. In the near-field region, the antenna's radiated power density deviates from the antenna pattern, with the power density directly in front of it decreasing while the lobe width slightly increases. This is the antenna's near-field effect. In the far-field region, the antenna radiates energy outward, while in the near-field region, an induced near-field exists. Energy in the induced near-field undergoes electromagnetic exchange in this region without radiation. Placing a dielectric or metal in this region, or even close to the antenna radiator, will significantly affect the antenna's surface current and radiation performance, including changes in the antenna's resonant frequency band, gain, and radiation efficiency.

[0077] The primary function of an antenna is to convert electromagnetic signals in space into induced voltage or current signals for reception and detection. However, the voltage or current detected by each antenna is often not solely dependent on the known incident electromagnetic signal. The voltage signal sensed by the antenna may also be related to the voltage or current signals of other adjacent antennas. Therefore, the voltage signal received by each antenna will induce a current signal in its own antenna element. This current signal, in turn, stimulates an electromagnetic field that affects the signals on adjacent antennas. This effect is called antenna coupling. As shown in Table 1, direct coupling fields and indirect coupling fields can exist between antennas. The direct coupling field can be generated by the operation of the transmitting and receiving antennas and the excitation of the radiation zone (far field). In the direct coupling field mode, the main factor affecting the operation of the transmitting and receiving antennas is the power coupling between the transmitting and receiving antennas, which is partially affected by the NVCM coating. While a normal NCVM coating has little effect, an abnormal NCVM coating (with a certain degree of conductivity) consumes some energy. The abnormal NCVM coating generates an induced current in the coupling field between the transmitting and receiving antennas, which stimulates the coupling field to react on the transmitting and receiving antennas, thus forming an indirect coupling field. In the indirect coupling field working mode, the excited indirect coupling field has a certain amplitude, and the phases corresponding to these amplitudes are opposite, which can offset part of the energy of the direct coupling field. In addition, the indirect coupling field will quickly weaken as the battery cover moves away from the transceiver antenna.

[0078] Antenna loading refers to adding a load to the antenna. Antenna loading can change the current distribution on the antenna so that the input impedance of the antenna can be distributed according to a certain pattern. There are several ways to load the antenna. Among them, dielectric loading is to add a dielectric around the antenna to relatively shorten the antenna length; distributed loading is to load the antenna according to a certain position function, and the input impedance will also show a certain regular change. As shown in Table 1, when the antenna is tightly attached to the battery cover, the tightly attached battery cover can be regarded as the loading of the antenna, while the normal NCVM coating is dielectric loading, and the abnormal NCVM coating is distributed parameter loading. Therefore, the distributed parameter loading introduced by the battery cover with abnormal NCVM coating will affect the input impedance of the antenna, causing impedance mismatch, which may affect the impedance bandwidth, efficiency, etc.

[0079] Table 1

[0080]

[0081]

[0082] In an embodiment of the present application, the battery cover can be placed tightly against the surface of the radiator of at least one antenna (transmitting antenna 302 and / or receiving antenna 303). The coupling and loading effects of the battery cover NCVM coating can be used to produce differences in the radiation performance of the transceiver antenna. Then, the difference in power received by the receiving antenna 303 caused by the battery cover NCVM coating can be used to determine whether the battery cover NCVM coating is abnormal. The radiator surface of the antenna refers to the surface portion of the metal conductor of the antenna. The above-mentioned coupling and loading effects first refer to the energy coupling effect between the transceiver antenna and the abnormal battery cover NCVM coating. Part of the energy can be coupled to the abnormal battery cover NCVM coating and absorbed and dissipated by the abnormal battery cover NCVM coating. Secondly, since the abnormal battery cover NCVM coating is conductive, when it is placed tightly against the surface of the transceiver antenna radiator, it can produce a loading effect on the transceiver antenna, causing the surface current of the transceiver antenna to change and reducing the radiation efficiency of the receiving antenna 303.

[0083] Specifically, the battery cover can be placed between the transmitting antenna 302 and the receiving antenna 303, with the radiator surface of at least one antenna in close contact with the battery cover. The control module 305 can control the RF signal module 301 to output a first signal with a specific power and frequency, which is transmitted via the transmitting antenna 302. The first signal can then be incident on the battery cover. When the NCVM coating on the battery cover is normal, the battery cover exhibits minimal obstruction to the first signal, primarily manifested as the incident wave (first signal) passing through the battery cover. This also has minimal impact on the radiation performance of the receiving antenna 303. When the NCVM coating on the battery cover is abnormal, due to its conductivity, some of the first signal will be reflected by the abnormal NCVM coating. Furthermore, the abnormal NCVM coating on the battery cover will couple and load the receiving antenna 303, potentially degrading the radiation efficiency and radiation pattern of the receiving antenna 303, thereby reducing the signal power value received by the receiving antenna 303. Therefore, the presence of an abnormal NCVM coating on the battery cover can be determined by comparing the absolute value of the difference between the power value and the third threshold value with the fourth threshold value.

[0084] In one embodiment, the control module 305 is further configured to display the detection result of the NCVM coating.

[0085] The control module 305 may also include a display that can display the test result of the NCVM coating on a battery cover, that is, whether the NCVM coating on the battery cover is normal or abnormal. The display may also display the received power value and other relevant information.

[0086] The embodiments of the present application provide a low-cost, simple, effective, and non-destructive detection solution for the NCVM coating on the battery cover. This solution can intercept all battery covers with excessively thick NCVM coatings, thereby preventing missed detections caused by excessively thick NCVM coatings. It is important to note that the radiator surface of the transmitting antenna 302 and / or the receiving antenna 303 is placed in close contact with the battery cover. This facilitates the differentiation of radiation performance through coupling and loading effects, thereby determining whether the battery cover is normal.

[0087] See also Figure 4 , Figure 4 This is a schematic diagram of the structure of another battery cover NCVM coating detection device disclosed in the embodiment of this application. Figure 4 The battery cover NCVM coating detection device shown is composed of Figure 3 The battery cover NCVM coating detection device shown is optimized. Figure 4 As shown, in the battery cover NCVM coating detection device, the transmitting antenna 402 and / or the receiving antenna 403 are located on both sides of the battery cover.

[0088] The transmitting antenna 402 and receiving antenna 403 can be placed on both sides of the battery cover, with at least one of the antennas in close contact with the battery cover. Preferably, the transmitting antenna 402 is in close contact with the battery cover, while the receiving antenna 403 is kept at a certain distance from the battery cover; the transmitting antenna 402 is kept at a certain distance from the battery cover, while the receiving antenna 403 is in close contact with the battery cover.

[0089] Preferably, the transmitting antenna 402 and the receiving antenna 403 may be microstrip antennas.

[0090] In the embodiment of the present application, the battery cover can be placed closely against the radiator surface of at least one antenna (transmitting antenna 402 and / or receiving antenna 403). The coupling and loading effects of the battery cover NCVM coating can be used to produce differences in the radiation performance of the receiving microstrip antenna. Then, the power value of the received signal (second signal) can be used to determine whether the battery cover NCVM coating is abnormal. The entire detection process can cause no damage to the battery cover; the physical components involved in the detection process are relatively low-cost and do not involve expensive components such as vector network analyzers; the NCVM coating of all battery covers can be tested, which can avoid missed detections; the operation is simple, requiring only the battery cover to be picked up and placed for testing; the detection is convenient and rapid, and it only takes 3 to 4 seconds to test a battery cover; the detection effect is significant. For example, the difference between normal and abnormal values ​​of two different types of battery covers can reach 3.5dB and 9dB respectively; the detection scheme is universal, and different types of battery covers can be directly tested without the need to prepare test fixtures for different types of battery covers.

[0091] It should be noted that, in the specific placement of the transmitting antenna 402, the receiving antenna 403 and the battery cover, the position of the battery cover can block the direct path of the signal between the transmitting sky and the receiving antenna 403, which can be regarded as a reasonable placement, that is, it can be regarded as the scope of protection of this application. In actual operation, the shape and structure of the battery cover may be taken into consideration. In one case, the center point or the middle position of the battery cover (the battery cover can be regarded as a flat figure) can be selected as the placement position of the transmitting antenna 402 and the receiving antenna 403. In another case, the specific design of the battery cover may also be taken into consideration (for example, there is no NCVM coating at the camera of the mobile phone battery cover), and this part can be avoided, and the lower position of the battery cover can be selected as the placement position of the transmitting antenna 402 and the receiving antenna 403.

[0092] For detailed description, please refer to Figure 3 The relevant description in is not repeated here.

[0093] See also Figure 5 , Figure 5 This is a schematic diagram of the structure of another battery cover NCVM coating detection device disclosed in the embodiment of this application. Figure 5 The battery cover NCVM coating detection device shown is composed of Figure 3 The battery cover NCVM coating detection device shown is optimized. Figure 5 As shown, in the battery cover NCVM coating detection device, the transmitting antenna 502 and the receiving antenna 503 are located on the same side of the battery cover.

[0094] The transmitting antenna 502 and the receiving antenna 503 can be placed on both sides of the battery cover. At least one of the transmitting antenna 502 and the receiving antenna 503 is in close contact with the battery cover. Preferably, the transmitting antenna 502 is in close contact with the battery cover, and the receiving antenna 503 is in close contact with the battery cover.

[0095] Preferably, the transmitting antenna 502 and the receiving antenna 503 may be monopole antennas.

[0096] In the embodiments of the present application, the battery cover can be placed closely against the radiator surface of the transceiver antenna, utilizing the coupling and loading effects of the NCVM coating on the battery cover to produce differences in the radiation performance of the transceiver antenna. The power difference caused by the NCVM coating on the battery cover at the receiving antenna 503 can then be used to determine whether the NCVM coating on the battery cover is abnormal. The entire detection process does not damage the battery cover; the physical components involved in the detection process are relatively low-cost, and no expensive components such as vector network analyzers are involved. The NCVM coatings on all battery covers can be tested one by one, avoiding missed detections. The operation is simple, requiring only the battery cover to be picked up and placed for testing. Testing is quick and easy, requiring only 3 to 4 seconds to test a single battery cover. The detection effect is significant; for example, the difference between normal and abnormal values ​​for two different types of battery covers can reach 6.5dB and 18dB, respectively. The detection solution is universal, allowing direct testing of different types of battery covers without the need for custom test fixtures.

[0097] It should be noted that in Figure 4 In the previous embodiment, the detection results can range from 3.5dB to 9dB, while in this embodiment, the detection results can range from 6.5dB to 18dB, which is basically double the detection effect. In addition, because the transmitting and receiving antennas are on the same side of the battery cover in this embodiment, the operation of placing the battery cover during the detection process can be more convenient.

[0098] It should be further explained that the transmitting and receiving antennas are located on the same side of the battery cover, but the specific positions of the transmitting antenna 502 and the receiving antenna 503 and the distance between the two antennas are not limited.

[0099] Specifically, taking the mobile phone battery cover as an example, please refer to Figure 6 , Figure 6 Schematic diagram of a battery cover NCVM coating detection device disclosed in the embodiment of the present application. Figure 6As shown, the transmitting antenna 502 and the receiving antenna 503 are both transceiver printed monopole antennas, and the type of the transceiver antennas is 3GHz printed monopole antennas. The distance between the transceiver antennas is 5cm, and the battery cover and the transceiver antenna are both close to the battery cover. In order to facilitate the placement of the battery cover so that the battery cover is close to the surface of the transceiver antenna, a battery cover (decorative) deco groove is made next to the transceiver antenna. For example, the battery cover deco groove can be used to place the camera decoration of the mobile phone battery cover. In addition, the radio frequency signal module 501 is a simple RF signal source module, and the power meter module 504 is a simple power meter module. The transmitting antenna 502 and the simple RF signal source module are connected by a coaxial cable, and the receiving antenna 503 and the simple power meter module are also connected by a coaxial cable.

[0100] It should be noted that the above Figure 6 In the device, the center frequency of the transceiver printed monopole antenna is 3 GHz, and S11 = -20 dB (input reflection coefficient). During testing, the battery cover must be as close to the antenna radiator surface as possible. To ensure that the battery cover is in close contact with the transceiver antenna surface, the protruding slot of the battery cover can be placed in the battery cover slot next to the transceiver antenna. The core component of the simple RF signal source module is a phase-locked loop chip. The simple and low-cost ADF4351 module has a programmable upper limit of 4.4 GHz for the output frequency, and a dual-channel orthogonal output power of -5 to +5 dBm. To match the center frequency of the transceiver antenna, it must be set to 3 GHz (set by default). The simple RF signal source module has five buttons: left, right, up, and down for control, and the center button for confirmation. It has a display screen and can set the transmit power (first threshold) and transmit frequency (second threshold). The core component of the simple power meter module is a power detector chip. This low-cost, simple power detector module has an upper frequency limit of 8 GHz and a dynamic range of -50 dBm to 0 dBm. It converts the power signal from the receiving antenna 503 into a voltage value, which is then displayed on an organic light-emitting diode (OLED) display using a table lookup. The module also has five buttons: the left, right, and top buttons are control buttons, and the center button is an OK button (which must be pressed once after each power-up to activate the display). This button sets the receiving frequency, which must be set to 3 GHz (default) to match the center frequency of the transmitting and receiving antennas. A coaxial cable is used for connection, and this coaxial cable must cover the aforementioned operating frequency band.

[0101] Please refer to Figure 7 , Figure 7 This is a schematic diagram of a battery cover NCVM coating detection operation disclosed in an embodiment of the present application. Taking a mobile phone battery cover as an example, assuming that the third threshold value determined in the current type of battery cover is -19dBm and the fourth threshold value is 5dBm. Figure 7As shown in (a), the power value of the second signal detected by the receiving antenna 503 is -19.3dBm. Since |(-19.3)-(-19)|<5, it can be determined that the NCVM coating of the current battery cover is normal. Figure 7 As shown in (b), the power value of the second signal detected by the receiving antenna 503 is read as -26.7dBm. Since |(-26.7)-(-19)|>5, the current power difference is determined to be 7.7dBm, and it can be determined that the NCVM coating of the current battery cover is abnormal.

[0102] For detailed description, please refer to Figure 3 The relevant description in is not repeated here.

[0103] See also Figure 8 , Figure 8 Schematic diagram of a battery cover NCVM coating detection method disclosed in the embodiment of the present application. Figure 8 As shown, the method is applied to a battery cover NCVM coating detection device, which includes a radio frequency signal module, a transmitting antenna, a receiving antenna, a power meter module, and a control module. The battery cover NCVM coating detection method may include the following steps:

[0104] 801. Control the radio frequency signal module through the control module to excite the transmitting antenna to transmit a first signal.

[0105] The power of the first signal may be a first threshold, and the frequency of the first signal may be a second threshold.

[0106] In one embodiment, controlling the radio frequency signal module through the control module to excite the transmitting antenna to transmit the first signal includes: sending a control signal to the radio frequency signal module through the control module, the control signal including a first threshold and a second threshold; generating the first signal according to the first threshold and the second threshold through the radio frequency signal module; and transmitting the first signal through the transmitting antenna.

[0107] For detailed description, please refer to Figure 3 、 Figure 4 and Figure 5 Related description.

[0108] 802. Receive a second signal through a receiving antenna.

[0109] The second signal may be received by the receiving antenna, wherein the second signal may be a signal of the first signal passing through the battery cover.

[0110] 803. Detect the power value of the second signal through the power meter module.

[0111] The power value of the second signal may be measured by the power meter module and then sent to the control module.

[0112] 804. Determine whether the NCVM coating of the battery cover is normal based on the power value and the third threshold value through the control module.

[0113] The control module may receive a power value from the power meter module, and then determine whether the NCVM coating of the battery cover is normal based on the power value and a third threshold.

[0114] In one embodiment, determining whether the NCVM coating of the battery cover is normal according to the power value and the third threshold by the control module includes: when the absolute value of the difference between the power value and the third threshold is less than the fourth threshold, determining that the NCVM coating is normal by the control module.

[0115] In one embodiment, determining whether the NCVM coating of the battery cover is normal according to the power value and the third threshold by the control module includes: when the absolute value of the difference between the power value and the third threshold is greater than or equal to the fourth threshold, determining that the NCVM coating is abnormal by the control module.

[0116] In one embodiment, the detection result of the NCVM coating is displayed by the control module.

[0117] It should be noted that the relevant functions of the specific process in the battery cover NCVM coating detection method described in the embodiment of the present application can be found in the above Figure 3 、 Figure 4 and Figure 5 The relevant description in the embodiment of the battery cover NCVM coating detection device will not be repeated here.

[0118] In order to evaluate the feasibility and reliability of the above-mentioned battery cover NCVM coating detection solution, a preliminary experiment is conducted on the above-mentioned embodiment to determine the key factors and practical problems of the implementation plan.

[0119] According to the above embodiment, in the following detection process, the battery cover with normal NCVM coating is regarded as a “good” product or a good battery cover, and the battery cover with abnormal NCVM coating is regarded as a “bad” product or a bad battery cover. Figure 4 The scheme in which the transmitting antenna and the receiving antenna are located on both sides of the battery cover is called the "stacked model" scheme. Figure 5 The scheme in which the transmitting antenna and the receiving antenna are located on the same side of the battery cover is called the "horizontal model" scheme.

[0120] The first step is to determine the environment for the baseline test.

[0121] Table 2 shows the test environment for the baseline experiment. As shown in Table 2, two different types of battery caps (Taurus and Teller) were used for the baseline experiment. Eight Taurus battery caps were used, including five with normal NCVM coatings and three with abnormal NCVM coatings. Nineteen Teller battery caps were used, including five with normal NCVM coatings and 14 with abnormal NCVM coatings.

[0122] Table 2

[0123]

[0124] In the stacking model scheme, the specific placement of each component can refer to Figure 4 . In this case, the transceiver antenna can be a microstrip antenna, the microstrip antenna can be a side-fed antenna, and the transceiver antenna can be placed on a FR4 (fiberboard) substrate (fiberglass board). The RF signal module can be an RF signal source, and the RF signal source can be a simple ADF4351 module, the maximum frequency of its output signal can be 4.4GHz, and the power of the output signal can be a value between -5dBm and +5dBm. The power meter module can be a simple power detection module with an upper frequency limit of 8GHz and a measured dynamic range of -50 to 0dBm. The transmitting antenna and the RF signal module, and the receiving antenna and the power meter module can be connected through a reverse polarity male connector (Sub-Miniature-A, SMA) coaxial cable. Among them, the loss of the SMA coaxial cable is stable. The control module may include an STM32 series microcontroller. The test fixture can be built on site, and the corresponding operation is simple and the reliability is high.

[0125] In the horizontal model scheme, the specific placement of each component can refer to Figure 5 , in this case, the transceiver antenna can be a monopole antenna. The remaining components and connection methods can refer to the description of the stacking model solution above and are not repeated here.

[0126] The second step is to verify the detection method for the two models mentioned above.

[0127] For the two solutions mentioned above, the control module can respectively detect the NCVM coating of the battery cover using two methods, and then determine the final detection method used for each solution based on the test results. The two methods are the S parameter determination method and the power determination method. The S parameter determination method: The scattering coefficient curve of the electromagnetic wave can be measured first, and the measured battery cover scattering coefficient curve can be compared with the scattering coefficient curve of the NCVM coating of the normal battery cover. When the difference between the two scattering curves (for example, S11) at certain frequency points is greater than a certain value, it can be understood that the difference between the two scattering curves is relatively obvious. In this case, the NCVM coating of the measured battery cover can be determined to be abnormal; otherwise, it is normal. The power determination method: The power value of the received signal can be detected first, and then the power value of the detected battery cover can be compared with the power value of the NCVM coating of the normal battery cover. When the absolute value of the difference between the detected power value and the normal power value is greater than a certain value, the NCVM coating of the tested battery cover can be determined to be abnormal; otherwise, it is normal.

[0128] First, you can use the S parameter method to test. Figure 9 , Figure 9 Schematic diagram of a scattering coefficient curve disclosed in an embodiment of the present application, wherein the scattering coefficient (ie, S parameter) may include S11 input reflection coefficient, S21 forward transmission coefficient, and S22 output reflection coefficient. Figure 9 The horizontal axis is the frequency (GHz) and the vertical axis is the S parameter (dB). Figure 9 As shown in (a) in the figure, in the Taurus type battery cover, the S22 curve is the output reflection curve measured when the battery cover is not placed. It can be seen from S11 that the frequency deviation of the normal battery cover is basically the same as that of the abnormal battery cover, but the lowest point of the S21 curve of the abnormal battery cover is about 20dB lower than the lowest point of the normal S21 curve. Therefore, the resonance depth of the abnormal battery cover is inconsistent with that of the normal battery cover. Among them, the resonance depth of the abnormal battery cover is deeper than that of the normal battery cover. In addition, the S21 curve of the abnormal battery cover is higher than that of the normal battery cover. As shown in Figure 9 As shown in (b) of Figure 1, for a Teller-type battery cover, the S22 curve is also the output reflection curve measured without the battery cover in place. As can be seen from S11, there is some difference in frequency deviation between the normal and abnormal battery covers, and the lowest point of the S21 curve for the abnormal battery cover is only about 1 dB lower than that of the normal S21 curve. Therefore, the resonance depth of the abnormal and normal battery covers is essentially the same. Furthermore, the S21 curve for the abnormal battery cover is higher than that for the normal battery cover.

[0129] In the two different types of mobile phone battery covers mentioned above, when the NCVM coating is abnormal, the resistance of the NCVM coating on the Taurus battery cover is 10KΩ-20KΩ, and the resistance of the NCVM coating on the Teller battery cover is 1KΩ-3KΩ. Combined with the difference in the S21 curve, it can be concluded that the smaller the resistance of the battery cover NCVM coating, the larger the difference in the S21 curves between the normal and abnormal battery covers. In addition, since the frequency position of the lowest point of the S21 curve is lower than the frequency position of the lowest point of the S22 curve, when the battery cover is close to the surface of the antenna radiator, the NCVM coating of both the normal and abnormal battery covers can cause the antenna to produce a low-frequency deviation. In the Taurus battery cover, the frequency deviation produced by the normal battery cover and the abnormal battery cover is consistent, while in the Teller battery cover, the frequency deviation produced by the normal battery cover and the abnormal battery cover is inconsistent.

[0130] See also Figure 10 , Figure 10 This is a flow chart of comparison and analysis of S parameter determination disclosed in the embodiment of this application. Figure 9 As can be seen from the above S parameter comparison, the S parameter determination method experiment has uncertainty and still needs further verification. Figure 10 As shown, in the stacked mode solution, both the transmitting and receiving antennas are microstrip antennas. The S11 curve is affected by the battery cover type (Taurus and Teller), resulting in inconsistent resonance depth variations. Therefore, the S11 parameter method for detecting battery cover normality can be discarded. The S21 curve is not very sensitive to changes in values ​​between normal and abnormal Taurus battery covers, with the difference between the two being only approximately 1 to 1.5 dB, a subtle distinction. Therefore, the S21 parameter method for detecting battery cover normality remains to be determined. In the horizontal mode solution, both the transmitting and receiving antennas are monopoles. In the Taurus battery cover, the lowest point of the abnormal NCVM coating is 15 dB lower than the lowest point of the S11 curve (resonance depth) of the normal NCVM coating. In the Teller battery cover, the S11 curves for the abnormal and normal NCVM coatings show little difference, so the S11 parameter method for detecting battery cover normality can be discarded. The S21 curves show a clear difference between normal and abnormal NCVM coatings in both the Taurus and Teller battery covers, making the S11 parameter feasible. In summary, the S parameter method can be disregarded for now due to cost, development cycle, and experimental limitations.

[0131] Secondly, you can use the power determination method to test. Figure 11 , Figure 11 This is a flow chart of comparison and analysis of power determination disclosed in the embodiment of this application. Figure 11As shown, in the stacked configuration, when both the transmitting and receiving antennas are microstrip antennas, the factors influencing the difference between good and defective products can be identified first. The optimal parameters for each factor can then be determined based on the identified factors. Under optimal parameters, the power difference between good and defective products in the Taurus project was confirmed to be 3.5 dB, and the power difference between good and defective products in the Teller project was 9 dB. Therefore, the power difference between normal and abnormal battery covers is significant, making the power determination method feasible in this configuration. In the horizontal configuration, when both the transmitting and receiving antennas are microstrip antennas, the power determination method described above is not feasible due to the weak signal strength of the transmitting and receiving antennas. In the stacked configuration, when both the transmitting and receiving antennas are monopoles, the received signal at the receiving antenna is in the 1 to 3 dB range, which is easily affected by environmental factors or human interference, making this configuration unfeasible. In the horizontal configuration, when both the transmitting and receiving antennas are monopoles, the factors influencing the difference between good and defective products can be identified first. The optimal parameters for each factor can then be determined based on the identified factors. Under optimal parameter conditions, the power difference between a normal and abnormal battery cover in the Taurus project was 6.5dB, and the power difference between a normal and abnormal battery cover in the Teller project was 18dB. These significant differences indicate that this method is feasible. In summary, the power determination method is feasible in stacked mode when both the transmitting and receiving antennas are microstrip antennas, and in horizontal mode when both the transmitting and receiving antennas are monopoles.

[0132] The influencing factors in the baseline experiment can be referred to Table 3. As shown in Table 3, 8 influencing factors were identified during the implementation of the baseline experiment, and these 8 influencing factors were analyzed and screened.

[0133] Table 3

[0134]

[0135] The antenna form may include a microstrip antenna and a monopole antenna, wherein the microstrip antenna is preferably in a stacked mode and the monopole antenna is preferably in a horizontal mode.

[0136] Antenna placement can be performed in either stacked or horizontal configurations. In stacked configuration, monopole antennas are susceptible to environmental interference, resulting in received power fluctuations of 1-3 dB. Microstrip antennas, on the other hand, have a 3.5-9 dB difference between good and bad product detection. Therefore, microstrip antennas are preferred in stacked configurations. In horizontal configurations, microstrip antennas have a limited lobe width, resulting in small readings that fluctuate significantly. Monopole antennas, on the other hand, have a 6.5-18 dB difference between good and bad product detection. Therefore, monopole antennas are preferred in horizontal configurations. As can be seen from the above, antenna form and placement are optimally matched.

[0137] In the stacked mode with microstrip antennas (one of the transmit and receive antennas was placed close to the battery cover), the distance between the transmit and receive antennas varied from 3 to 9 cm, with the optimal distance being 5.5 cm. In the horizontal mode with monopole antennas (both transmit and receive antennas were placed close to the battery cover), the distance between the transmit and receive antennas varied from 3.5 to 7.5 cm, with the optimal distance also being 5.5 cm.

[0138] In the case of stacked mode and microstrip antennas, the distance between the battery cover and the antenna varied from 0 to 0.2 cm, with the optimal distance being 0 cm (i.e., right next to the battery cover). In the case of horizontal mode and monopole antennas, the distance between the battery cover and the antenna varied from 0 to 0.4 cm, with the optimal distance also being 0 cm.

[0139] The matching effect of antenna S11 is relatively poor, so antenna S11 should be ensured to be less than -10dB, preferably, S11 is less than -15dB.

[0140] The frequency band an antenna can operate in is related to its size. Smaller antennas operate at higher frequencies; similarly, larger antennas operate at lower frequencies. Therefore, if the antenna's frequency band is too low, the antenna is too large and susceptible to interference. If the antenna's frequency band is too high, the antenna is too small, the battery cover is less sensitive, and signal loss is high. Microstrip antennas are preferably 4 GHz, and monopole antennas are preferably 3 GHz.

[0141] When selecting the detection position of the antenna relative to the battery cover, the detection difference measured at the middle of the battery cover is about 1dB larger than that at the edge of the battery cover. The detection difference can be understood as the absolute value of the difference in power between good and defective products. Therefore, the middle of the battery cover is preferably used as the detection position of the antenna. In addition, considering the position of the battery cover camera (for example, the camera is in the upper middle part of the mobile phone battery cover), the position of the detection point (i.e., the position of the transceiver antenna) is adjusted to the lower middle part of the battery cover (avoiding the camera position).

[0142] When selecting the transmit and receive frequency band, it is necessary to consider that when the antenna is placed close to the battery cover, the center frequency of the antenna will shift to a lower frequency. Therefore, a frequency that is the same as the air frequency can be preferred.

[0143] In addition to the above-mentioned influencing factors, there may be interference factors that affect the verification results in actual operations. The verification process simulates the corresponding interference factors and ultimately confirms that these interference factors do not affect the feasibility and reliability of the detection scheme.

[0144] Interference factors a. The impact of the environment and human presence on the verification results of the monopole antenna solution in horizontal mode. When there is no battery cover between the transceiver antennas, metal or human hands within 10 cm of the antennas will cause interference, causing the received power value to fluctuate by approximately 1 dB. A standing person within 15 cm of the antennas will cause interference, causing the received power value to fluctuate by approximately 0.5 dB. A person with a bent head within 15 cm of the antennas will cause interference, causing the received power value to fluctuate by approximately 1 dB. When a good battery cover is placed between the antennas, the above effects are halved. Specifically, metal or human hands within 10 cm of the antennas will cause interference, causing the received power value to fluctuate by approximately 0.5 dB. A standing person within 15 cm of the antennas will cause interference, causing the received power value to fluctuate by approximately 0.25 dB. A person with a bent head within 15 cm of the antennas will cause interference, causing the received power value to fluctuate by approximately 0.5 dB. When a bad battery cover is placed between the antennas, the above effects are further reduced. The fluctuations of the above power values ​​are all within 1 dB, and the measurable difference is between 6.5-18 dB, so the impact on the test results is very small and can be ignored.

[0145] Interference factor b. When the battery cover and the transceiver antenna are "closely attached," there may be a gap due to improper placement, the presence of foreign objects, or the addition of a scratch-resistant separator. Table 4 shows the impact on the verification results (difference) when the battery cover and the transmitting antenna are in close but not perfect contact. According to experimental results, in horizontal mode, when the distance between the monopole antenna and the battery cover is within 0.5mm, the detection difference is reduced, but the margin (i.e., the difference in power between a normal and abnormal battery cover after the detection difference is reduced) is sufficient, and has no impact on detection accuracy.

[0146] Table 4

[0147]

[0148]

[0149] Interference factors c. See Figure 12 , Figure 12 Schematic diagram of a device for detecting NCVM coating of a battery cover with a flexible printed circuit (FPC) antenna disclosed in an embodiment of the present application. Figure 12As shown, the FPC antenna measures 2.5cm x 2.5cm, the height of each transmitting and receiving antenna is 3.5cm, and the distance between them is 5.5cm. When inspecting good and defective products with the FPC antenna attached to the battery cover, the impact of the FPC antenna on inspection performance must be considered. When the FPC antenna is attached to the battery cover, the power of the signal received by the receiving antenna decreases. Based on the magnitude of the signal power reduction, the impacting area can be categorized as a strong impact area, a moderate impact area, and a weak impact area. The weak impact area refers to the region where the received power decreases within 1dB; the moderate impact area refers to the region where the received power decreases within 1-3dB; and the strong impact area refers to the region where the received power decreases within 3-8dB. Within the strong impact area or the moderate impact area, as the quality of the battery cover changes—that is, as the battery cover changes from good to moderately defective to severely defective—the decrease in received power increases. Among them, good products are battery covers with normal NCVM coating, and general defective products and strong defective products refer to battery covers with abnormal NCVM coating. The detection difference of the battery cover with NCVM coating of strong defective products is greater than a certain value, while the detection difference of the battery cover with NCVM coating of general defective products is less than or equal to the above certain value. From this, it can be concluded that when detecting the battery cover with an FPC antenna, although the received power will be reduced, the detection margin is sufficient to effectively detect whether the NCVM coating of the battery cover is normal. Sufficient margin can be understood as under the interference of the above-mentioned interference factors, the difference between the detected good and defective products is reduced to a certain extent, but the difference detected after the reduction is large enough to distinguish between good and defective products. Even if the FPC antenna is attached to the strong influence area on the battery cover, it will not affect the accuracy of the detection results, but it is still recommended to avoid this area during detection.

[0150] Interference factor d. The impact of different battery cover thicknesses on test results. The battery cover thickness for the Taurus project was 0.77mm, while that for the Teller project was 0.66mm. The Taurus battery cover was 0.11mm thicker than the Teller battery cover, resulting in a 10MHz larger frequency deviation. Therefore, thickness has no direct correlation with test results.

[0151] Interference factor e. The influence of the poor NCVM coating on the battery cover. The resistance of the NCVM coating on a defective Taurus battery cover is between 10kΩ and 20kΩ, while that on a Teller battery cover is between 1kΩ and 3kΩ. The lower the resistance, the greater the degree of battery cover defect. Teller's detection performance (18dB) is better than Taurus's (6.5dB), indicating that the greater the degree of battery cover NCVM coating defect, the more significant the detection effect.

[0152] The third step is to determine the optimal parameters of multiple influencing factors.

[0153] The selection of the optimal parameters among multiple influencing factors can be referred to Table 5. As shown in Table 5, the factors affecting the power determination method are first verified with large sample data, and the optimal parameters corresponding to each factor are confirmed. Among them, the optimal signal source transmission power of the RF signal module is -4dBm; the optimal center frequency of the antenna is 3GHz; the optimal value of the S11 resonance depth is -22; the optimal height of the battery cover from the transmitting antenna is 0 (close to the antenna); the optimal position of the detection position relative to the battery cover is the lower middle or middle position of the battery cover. The antenna placement position in this experiment is horizontal mode, and a monopole antenna is preferred; it is preferred to have no FPC antenna; the frequency offset is preferably the same frequency as the air, and the distance between the transmitting and receiving antennas is preferably 5.5cm. Under the above preferred conditions, the power value of the received signal when there is no battery cover is -10.8dBm. Experiments are conducted using the optimal influencing factors to further determine the feasibility and reliability of the solution. Experiments show that for both types of battery covers, the average power difference between good and defective Taurus-type products is 6.9dB, while the average power difference between good and defective Teller-type products is 17.7dB, providing ample margin. Fluctuations in test values ​​for good battery covers of different types are minimal, all within 0.6dB. While Teller-type defective battery covers exhibited significant test value fluctuations (10dB) due to varying degrees of defectivity, the minimum difference between good and defective products was still 11dB, providing ample margin for verifying the integrity of the battery cover's NCVM coating.

[0154] Table 5

[0155] Influencing factors Optimal parameters Signal source transmission power value (dBm) -4dBm Antenna frequency 3GHz S11 resonance depth -22 Height from battery cover to transmitting antenna (mm) 0 (card position close to) Battery cover detection position Lower middle / middle Antenna bandwidth (GHz) 2.86-3.15 Antenna Type Monopole antenna Whether there is an FPC antenna none Air frequency synchronization and frequency offset synchronization Air frequency Antenna placement Horizontal parallel Distance between transmitting and receiving antennas (cm) 5.5 Received power without battery cover (dBm) -10.8

[0156] Table 6 shows the power determination method for each battery cover test data. As shown in Table 6, with the aforementioned influencing factors selected as optimal parameters, the received power values ​​of both good and defective battery covers of two types were measured, and their fluctuations were quantified. For the Taurus battery cover, the received power values ​​of the five good battery covers fluctuated within a 0.6dB range, with an average of -11.8dB. The received power values ​​of the three defective battery covers also fluctuated within a 0.6dB range, with an average of -18.7dB. The absolute difference between the average values ​​of the good and defective battery covers was 6.9dB. In the Teller battery cap test, the power meter received value test values ​​of the five good products fluctuated within a range of 0.2dB, with an average test value of -12.94dB. The power meter received value test values ​​of the 14 defective products fluctuated within a range of 10dB, with an average test value of -30.60714286dB. The absolute value of the difference between the average values ​​of the good products and the average values ​​of the defective products was 17.66714286dB.

[0157] Table 6

[0158]

[0159]

[0160] The results of the S-parameter (S21) and power-based methods can be seen in Table 7. As shown in Table 7, under identical conditions, the antenna frequency was set to 3 GHz. For the Taurus battery cover, the S21 value for good products was -13.4 dB, while that for defective products was -19 dB. The difference between good and defective S21 values ​​was 5.6 dB, compared to the 6.9 dB difference measured by the power-based method under the same conditions. For the Teller battery cover, the S21 value for good products was -14.3 dB, while that for defective products was -30 dB. The difference between good and defective S21 values ​​was 15.7 dB, compared to the 17.6 dB difference measured by the power-based method under the same conditions. In summary, compared to the measured S21 values, both the received power-based method and the S21 parameter-based method can effectively detect good and defective battery covers under the horizontal model when the transmitting and receiving antennas are monopoles. Among them, the S21 difference is only slightly lower than the power value difference, so the power judgment method is more effective.

[0161] Table 7

[0162]

[0163] The fourth step is simulation verification.

[0164] The power determination method and the S-parameter determination method (S21) theoretically have a certain correspondence. The trend of the power difference between good and defective products is consistent with the trend of the S21 difference. In this experiment, finite conductivity boundary conditions were used to simulate poor NCVM coating conditions. The effects of good and defective battery covers close to the antenna on the antenna radiation pattern and the S21 between the two antennas were verified, providing support for the experimental measured data.

[0165] See also Figure 13 , Figure 13 This is a schematic diagram of a simulation model for detecting NCVM coating on a battery cover disclosed in an embodiment of the present application. Figure 13 As shown, two monopole antennas in the horizontal mode are placed on both sides, and the two antennas (transmitting and receiving antennas) are 5.5 cm apart. Each antenna includes an antenna ground, a monopole radiator and an FR4 medium. The thickness of the battery cover simulation is 0.5 mm, and the finite conductivity boundary condition of the NCVM coating simulation is that the conductivity is equal to 2.

[0166] When placing different battery cover conditions (i.e., no battery cover, good battery cover, and bad battery cover), the radiation gain of the antenna can be referred to Table 8. As shown in Table 8, when the radiation direction of the antenna (transmitting antenna) is Theta = 0 / phi = 0 and the antenna frequency is 4 GHz, the gain of the antenna is 0.97 dB when there is no battery cover, -0.05 dB when there is a good battery cover, and -23.5 dB when there is a bad battery cover; when the radiation direction of the antenna (transmitting antenna) is Theta = 0 / phi = 0 and the antenna frequency is 3.55 GHz, the gain of the antenna is -0.37 dB when there is no battery cover, 1.37 dB when there is a good battery cover, and -13.2 dB when there is a bad battery cover. dB; when the antenna (receiving antenna)'s radiation direction is Theta = 90 / phi = 0 and the antenna frequency is 4 GHz, the antenna gain is 0.76 dB without a battery cover, -0.05 dB with a good battery cover, and -17.3 dB with a bad battery cover; when the antenna (receiving antenna)'s radiation direction is Theta = 90 / phi = 0 and the antenna frequency is 3.55 GHz, the antenna gain is -0.37 dB without a battery cover, 1.37 dB with a good battery cover, and -9.4 dB with a bad battery cover. Therefore, simulation analysis shows that a good battery cover has little effect on the antenna pattern, while a bad battery cover will weaken the antenna's overall radiation capability and distort the radiation pattern.

[0167] Table 8

[0168] Radiation direction No 4G No 3.55G Good 4G Good 3.55G Bad 4G Defective 3.55G Theta=0 / phi=0 0.97dB -0.37dB -0.05dB 1.37dB -23.5dB -13.2dB Theta=90 / phi=0 0.76dB -0.37dB -0.05dB 1.37dB -17.3dB -9.4dB

[0169] See also Figure 14 , Figure 14 It is a schematic diagram of the simulation results of the battery cover NCVM coating detection disclosed in an embodiment of the present application. Among them, OK means that the NCVM coating of the battery cover is normal, NG means that the NCVM coating of the battery cover is abnormal, and S22 is the output reflection curve when the battery cover is not placed. In the S11 parameter, both good and defective products will produce some frequency deviation relative to when the battery cover is not placed, and the frequency deviation is inconsistent, and the resonance depth of good and defective products is not much different. Therefore, the S11 parameter cannot detect good and defective products. Under the optimal parameter setting model, the S21 parameter simulation analysis found that defective products can make the test transceiver antenna S21 worse, and the trend is basically consistent with the results of the baseline experiment.

[0170] The battery cover has a large relative dielectric constant, which can cause the antenna resonant frequency to shift toward a low frequency. Poor NCVM coating is equivalent to a conductor with finite conductivity. When the battery cover is close to the antenna radiator, the radiation performance of the antenna will deteriorate and the S parameters of the antenna will also be affected. Different types of antennas respond differently to poor battery covers. Parameters that affect the ability to detect battery cover NCVM coating may include the form of the antenna, such as the antenna's directivity and the antenna's resonance.

[0171] In summary, this preliminary experiment verified and analyzed the feasibility and reliability of two proposed schemes for early detection of NCVM anomalies in battery cover coatings (Taurus and Teller). The power determination method offers low cost, a short development cycle, significant detection results (over 6dB), and practical feasibility. The most significant detection results were achieved using microstrip antennas for the stacked model and monopole antennas for the horizontal model. The preliminary experiment also identified the optimal implementation plan, verified factors influencing its implementation, and identified potential practical problems. The scheme demonstrated sufficient detection margin and high reliability.

[0172] The specific implementation methods described above further illustrate the purpose, technical solutions and beneficial effects of this application. It should be understood that the above description is only the specific implementation methods of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent replacements, improvements, etc. made on the basis of the technical solutions of this application should be included in the scope of protection of this application.

Claims

1. A battery cover non-conductive electroplating technology NCVM coating detection device, characterized in that: It includes a radio frequency signal module, a transmitting antenna, a receiving antenna, a power meter module and a control module, wherein: The radio frequency signal module is respectively coupled to the transmitting antenna and the control module, the power meter module is respectively coupled to the receiving antenna and the control module, and the transmitting antenna and / or the receiving antenna is closely attached to the battery cover; The control module is configured to control the radio frequency signal module to excite the transmitting antenna to transmit a first signal, where the power of the first signal is a first threshold and the frequency of the first signal is a second threshold; The receiving antenna is configured to receive a second signal, where the second signal is a signal of the first signal passing through the battery cover; The power meter module is used to detect the power value of the second signal; The control module is further configured to determine whether the NCVM coating of the battery cover is normal according to the power value of the second signal and a third threshold.

2. The device according to claim 1, characterized in that The control module controlling the radio frequency signal module to excite the transmitting antenna to transmit the first signal includes: The control module is configured to send a control signal to the radio frequency signal module, wherein the control signal includes the first threshold and the second threshold; The radio frequency signal module is configured to generate a first signal according to the first threshold and the second threshold; The transmitting antenna is used to transmit the first signal.

3. The device according to claim 1 or 2, characterized in that The transmitting antenna and / or the receiving antenna are located on both sides of the battery cover.

4. The device according to claim 1 or 2, characterized in that The transmitting antenna and the receiving antenna are located on the same side of the battery cover.

5. The device according to claim 1 or 2, characterized in that The control module determines whether the NCVM coating of the battery cover is normal according to the power value of the second signal and a third threshold value, including: When the absolute value of the difference between the power value of the second signal and the third threshold is smaller than the fourth threshold, it is determined that the NCVM coating is normal.

6. The device according to claim 5, characterized in that The control module determines whether the NCVM coating of the battery cover is normal according to the power value of the second signal and a third threshold value, further comprising: When the absolute value of the difference between the power value of the second signal and the third threshold is greater than or equal to a fourth threshold, it is determined that the NCVM coating is abnormal.

7. The device according to claim 6, characterized in that The control module is also used to display the detection results of the NCVM coating.

8. A battery cover non-conductive electroplating technology NCVM coating detection method, characterized in that: The method is applied to a battery cover NCVM coating detection device, which includes a radio frequency signal module, a transmitting antenna, a receiving antenna, a power meter module, and a control module. The method includes: Controlling the radio frequency signal module through the control module to excite the transmitting antenna to transmit a first signal, where the power of the first signal is a first threshold and the frequency of the first signal is a second threshold; receiving a second signal through the receiving antenna, where the second signal is a signal of the first signal passing through the battery cover; detecting a power value of the second signal by the power meter module; The control module determines whether the NCVM coating of the battery cover is normal according to the power value of the second signal and a third threshold.

9. The method according to claim 8, characterized in that The controlling the radio frequency signal module by the control module to excite the transmitting antenna to transmit the first signal includes: Sending a control signal to the radio frequency signal module through the control module, wherein the control signal includes the first threshold and the second threshold; generating a first signal by the radio frequency signal module according to the first threshold and the second threshold; The first signal is transmitted through the transmitting antenna.

10. The method according to claim 8 or 9, characterized in that The determining, by the control module, whether the NCVM coating of the battery cover is normal according to the power value of the second signal and a third threshold value includes: When the absolute value of the difference between the power value of the second signal and the third threshold is smaller than a fourth threshold, the control module determines that the NCVM coating is normal.

11. The method according to claim 10, characterized in that The determining, by the control module, whether the NCVM coating of the battery cover is normal according to the power value of the second signal and a third threshold value further includes: When the absolute value of the difference between the power value of the second signal and the third threshold is greater than or equal to a fourth threshold, the control module determines that the NCVM coating is abnormal.

12. The method according to claim 11, characterized in that The method further comprises: The detection result of the NCVM coating is displayed by the control module.

Images