Probe connector device for PCB (Printed Circuit Board) connection test

Abstract

The invention relates to the technical field of PCB (Printed Circuit Board) connection test, in particular to a probe connector device for PCB connection test, which comprises a data acquisition module and a test control module, the test control module comprises an interface contact quality determination unit used for determining whether the interface contact quality of the test probe and the test position is qualified or not based on the resistance variation coefficient. The spring strain determination unit is used for setting a plurality of voltage regulation coefficients to regulate the control voltage of the piezoelectric ceramic piece based on a comparison result of the compression state characterization value and a preset compression state characterization value, and is used for determining a position where the interface contact pressure is unqualified based on the temperature abnormal range; the spring strain correction unit is used for setting a plurality of voltage correction coefficients according to the temperature difference and optimizing the voltage adjustment coefficient; and the strain threshold value adjustment unit is used for adjusting the preset compression state characterization value based on the optimization frequency of the voltage correction coefficients. According to the invention, the interface contact quality of the test probe and the PCB is improved.

Description

Technical Field

[0001] This invention relates to the field of PCB board connection testing technology, and in particular to a probe connector device for PCB board connection testing. Background Technology

[0002] In the field of high-precision PCB testing, probe connectors are core components for achieving electrical connections between testing equipment and PCB test points. The contact quality between the movable outer conductor and the movable inner conductor at the PCB interface directly affects the reliability and accuracy of the test results. In traditional probe connectors, the movable outer conductor (shielding ring) contacts the periphery of the PCB test point through elastic pressure to isolate external electromagnetic interference; the movable inner conductor (probe) directly presses against the test point to achieve signal transmission. However, during long-term testing, the contact quality between the two conductors and the PCB interface is easily affected by multiple factors: First, the spring of the moving outer conductor experiences stiffness reduction due to material fatigue and plastic deformation, resulting in pressure fluctuations under the same compression. This leads to inconsistent contact tightness between the shielding layer and the PCB, potentially causing electromagnetic interference coupling (such as high-frequency signal crosstalk) due to insufficient pressure, or scratching the PCB pads due to excessive pressure. Second, when the probe tip of the moving inner conductor (probe) contacts the PCB test point, oxide layers, contaminants, or solder residues easily accumulate at the interface, leading to abnormally high contact resistance and affecting the stability of electrical signal transmission. Third, the contact state between the two conductors and the PCB interface (such as pressure uniformity and fit) gradually deteriorates with the increase in the number of tests, resulting in increased dispersion of repeated test results at the same test point and ultimately causing test misjudgments. These problems are particularly prominent in high-frequency, high-density PCB testing, severely restricting the improvement of testing efficiency and product yield. Therefore, it is urgent to design a probe connector device that can stably ensure the contact quality between the moving outer conductor and the moving inner conductor and the PCB interface.

[0003] Chinese Patent Application Publication No. CN102239602A discloses a probe connector that connects a circuit board and a coaxial plug including an axial terminal and surrounding terminals. The coaxial probe of this probe connector includes a center terminal and an outer terminal. The center terminal is connected to the circuit board and the axial terminal, while the outer terminal is coaxial with the center terminal and connected to the circuit board and the surrounding terminals. The outer terminal includes a cylindrical outer conductor, an anchor, and a conductive cap. The cylindrical outer conductor surrounds the center terminal and mates with the surrounding terminals. The anchor is formed as a protrusion on a portion of the outer surface of the outer conductor by a machining process, thereby forming a hole in the portion of the outer surface. The conductive cap covers and closes the hole and is electrically connected to the outer conductor. Therefore, even when the coaxial plug is inserted into or removed from the coaxial probe, the position of the coaxial probe will only shift slightly.

[0004] The existing technology also has the following problems: repeated testing of the probe connector can lead to a decrease in the plastic deformation of the springs of the active outer conductor and the active inner conductor, or the insufficient flatness of the test surface of the PCB board can lead to poor interface contact quality between the probe connector and the PCB board, resulting in low test accuracy. Summary of the Invention

[0005] To address this, the present invention provides a probe connector device for PCB board connection testing, which overcomes the problems in the prior art where repeated testing leads to a decrease in the plastic deformation of the springs of the active outer conductor and the active inner conductor, or where insufficient flatness of the test surface of the PCB board results in poor interface contact quality between the probe connector and the PCB board, thus leading to low test accuracy.

[0006] To achieve the above objectives, the present invention provides a probe connector device for PCB board connection testing, comprising: The data acquisition module includes an infrared acquisition component for acquiring temperature distribution images on the surface of the PCB board, and a strain sensor for acquiring spring deformation. The test control module includes, An interface contact quality determination unit is used to determine a resistance variation coefficient based on several contact resistances between a test probe and a test position, so as to determine whether the interface contact quality between the test probe and the test position is qualified according to the resistance variation coefficient. A spring strain determination unit is used to determine the compression state characterization value of the outer conductor spring or the inner conductor spring based on the strain value of the strain sensor, and to set several voltage adjustment coefficients to adjust the control voltage of the piezoelectric ceramic sheet according to the comparison result of the compression state characterization value and the preset compression state characterization value. A spring strain correction unit is used to determine the temperature anomaly range based on the temperature distribution image, to determine that the interface contact pressure between the active outer conductor or the active inner conductor and the test position is unqualified based on the temperature anomaly range, and to optimize the voltage regulation coefficient by setting several voltage correction coefficients according to the temperature difference between the highest temperature in the temperature anomaly range and the preset temperature. A strain threshold adjustment unit is used to adjust the preset compression state characterization value based on the optimized frequency of the voltage correction coefficient.

[0007] Furthermore, the probe connector device further includes: A test probe includes a movable outer conductor for shielding signals, an outer conductor spring for extending and retracting the movable outer conductor, a first piezoelectric ceramic plate coaxially mounted with the outer conductor spring, a movable inner conductor coaxially mounted with the movable outer conductor for establishing an electrical connection, an inner conductor spring for extending and retracting the movable inner conductor, and a second piezoelectric ceramic plate coaxially mounted with the inner conductor spring, wherein strain sensors are embedded inside the steel wires of the outer conductor spring and the inner conductor spring, respectively. The probe connection mechanism includes a first probe connection mechanism and a second probe connection mechanism. The first probe connection mechanism includes a plurality of first single channels for placing a plurality of test probes, a first pressing plate for fixing a plurality of the first single channels, a first main body bracket that fits into the first pressing plate to provide rigid support, and a positioning post disposed at the bottom of the first main body bracket for aligning the PCB board and the probe connector. The second probe connection mechanism includes a plurality of second single channels for placing a plurality of test probes, a second pressing plate for fixing a plurality of the second single channels, a second main body bracket that engages with the second pressing plate to provide rigid support, and connecting bolts disposed at the bottom of the second main body bracket for fixing the PCB board and the probe connector.

[0008] Furthermore, the interface contact quality determination unit determines that the interface contact quality is unqualified based on the comparison result that the resistance variation coefficient is greater than the preset resistance variation coefficient. The interface contact quality determination unit determines that the interface contact quality is qualified based on the comparison result that the resistance variation coefficient is less than or equal to the preset resistance variation coefficient.

[0009] Furthermore, when the spring strain determination unit determines that the interface contact quality is unqualified, it sets several voltage adjustment coefficients based on the comparison result between the compression state characterization value and the preset characterization value, so as to increase the control voltage of the piezoelectric ceramic sheet based on the several voltage adjustment coefficients.

[0010] Furthermore, the spring strain correction unit determines, based on the comparison result that the temperature anomaly range is greater than the first preset range, that the interface contact pressure between the active outer conductor and the active inner conductor and the test position is unqualified.

[0011] Furthermore, the spring strain correction unit determines that the interface contact pressure between the active outer conductor and the test position is unqualified based on the comparison result that the temperature anomaly range is less than or equal to the first preset range and greater than the second preset range.

[0012] Furthermore, the spring strain correction unit determines that the interface contact pressure between the active inner conductor and the test position is unqualified based on the comparison result that the temperature anomaly range is less than or equal to the second preset range.

[0013] Furthermore, when the interface contact pressure is determined to be unqualified, the spring strain correction unit sets several voltage correction coefficients based on the comparison result between the temperature difference and the preset difference, so as to optimize the voltage regulation coefficient based on the several voltage correction coefficients.

[0014] Furthermore, the strain threshold adjustment unit determines to adjust the preset compression state characterization value based on the comparison result of the optimized frequency being greater than the preset frequency.

[0015] Furthermore, the strain threshold adjustment unit sets several threshold adjustment coefficients based on the frequency difference between the optimized frequency and the preset frequency, so as to increase the preset compression state characterization value according to the several threshold adjustment coefficients.

[0016] Compared with existing technologies, the advantages of this invention lie in the fact that it uses a four-probe method to determine the contact resistance between the active outer conductor and the active inner conductor of the test probe and the test position, thereby determining the resistance variation coefficient at several contact positions. The core function of the active outer conductor is to achieve electromagnetic shielding through low-impedance connection; its contact resistance with the test point must be as small as possible to reduce signal reflection and energy loss at the interface. The core function of the active inner conductor is to achieve low-loss transmission of the test signal; the contact resistance between the probe and the test point must be kept low to ensure the integrity of signal transmission. For probe connectors integrating multiple test probes, the interface contact quality between the probe connector and the PCB board can be determined by the resistance variation coefficient; the smaller the resistance variation coefficient, the better the interface contact quality between the probe connector and the PCB board. For cases of substandard interface contact quality, the compression state characterization value of the spring of any test probe is determined to determine whether the insufficient spring compression value leads to insufficient contact pressure, thus causing substandard contact resistance. To address the issue of insufficient spring compression, the control voltage of the piezoelectric ceramic sheet is increased to enhance its deformation, thereby increasing the spring compression and improving the contact pressure of the test probe while reducing contact resistance. For cases where the interface contact quality is acceptable, temperature distribution images from the testing process are acquired to determine abnormal temperature ranges. Based on these ranges, it is determined whether the poor contact quality is due to the interface between the active outer conductor and the PCB board, the active inner conductor and the PCB board, or both. For each identified case, the corresponding voltage adjustment coefficient is optimized to improve the interface contact quality. After multiple tests, the rigidity of the built-in spring in the probe connector may decrease, resulting in less contact pressure provided by the same compression value. Therefore, a coefficient curve is established based on historical test data. By optimizing the frequency of the voltage correction coefficient, it is determined whether the spring rigidity has decreased, and the preset compression value is increased accordingly to further improve the interface contact quality and thus enhance testing accuracy.

[0017] Furthermore, this invention determines the location of unqualified interface contact pressure by measuring the temperature anomaly range. When the interface contact pressure of both the active outer conductor and the active inner conductor is unqualified, the temperature in the contact area of ​​the active inner conductor is the highest, followed by the temperature in the contact area of ​​the active outer conductor, radiating outwards from the active outer conductor to form a large temperature anomaly range. When the interface contact pressure of the active outer conductor is unqualified, the temperature is mainly concentrated in the contact area of ​​the active outer conductor, and the highest temperature is lower than when the interface contact pressure of both the active outer conductor and the active inner conductor is unqualified, resulting in a smaller temperature anomaly range. When the interface contact pressure of the active inner conductor is unqualified, the temperature is mainly concentrated at the contact point between the tip of the active inner conductor and the test point, resulting in the smallest temperature anomaly range. Therefore, the location of unqualified interface contact pressure can be determined by measuring the temperature anomaly range for targeted adjustments, thereby improving the interface contact quality and further enhancing the test accuracy. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of a test probe used for PCB board connection testing according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the probe connector device for PCB board connection testing according to an embodiment of the present invention; Figure 3 This is a structural block diagram of a probe connector device for PCB board connection testing according to an embodiment of the present invention; Figure 4 This is a flowchart for determining whether the interface contact quality is qualified according to an embodiment of the present invention; Figure 5 This is an enlarged view of part A of the present invention; Figure 6 This is an enlarged view of part B of the present invention; In the diagram: 1. Test probe, 2. Connector body, 3. Movable outer conductor, 4. Movable inner conductor, 5. Outer conductor spring, 6. Inner conductor spring, 7. First piezoelectric ceramic sheet, 8. Second piezoelectric ceramic sheet, 9. Strain sensor, 10. Cable, 11. First probe connection mechanism, 12. Second probe connection mechanism, 13. First single channel, 14. First pressing plate, 15. First main body support, 16. Positioning post, 17. Second single channel, 18. Second pressing plate, 19. Second main body support, 20. Connecting bolt, 21. Cover plate. Detailed Implementation

[0019] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0020] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0021] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0022] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0023] Please see Figures 1-6 As shown, Figure 1 This is a schematic diagram of the structure of a test probe used for PCB board connection testing according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the probe connector device for PCB board connection testing according to an embodiment of the present invention; Figure 3 This is a structural block diagram of a probe connector device for PCB board connection testing according to an embodiment of the present invention; Figure 4 This is a flowchart for determining whether the interface contact quality is qualified according to an embodiment of the present invention; Figure 5 This is an enlarged view of part A of the present invention; Figure 6 This is an enlarged view of part B of the present invention.

[0024] The probe connector device for PCB board connection testing according to embodiments of the present invention includes: A plurality of test probes 1, comprising a connector body 2, a movable outer conductor 3 disposed inside the connector body 2 for shielding signals, an outer conductor spring 5 connected to the movable outer conductor 3 for extending and retracting the movable outer conductor 3, a first piezoelectric ceramic plate 7 disposed on the outer conductor spring 5 and coaxially mounted with the outer conductor spring 5 at the end away from the movable outer conductor 3, a movable inner conductor 4 disposed inside the movable outer conductor 3 and coaxially mounted with the movable outer conductor 3 for establishing an electrical connection, an inner conductor spring 6 connected to the movable inner conductor 4 for extending and retracting the movable inner conductor 4, and a second piezoelectric ceramic plate 8 disposed on the inner conductor spring 6 and coaxially mounted with the inner conductor spring 6 at the end away from the movable inner conductor 4, wherein strain sensors 9 are embedded inside the steel wires of the outer conductor spring 5 and the inner conductor spring 6 respectively; Cable 10 is connected to the end of the test probe 1 near the outer conductor spring 5 to transmit test signals; The probe connection mechanism includes a first probe connection mechanism 11 and a second probe connection mechanism 12. The first probe connection mechanism 11 includes a plurality of first single channels 13 for placing a plurality of test probes 1, a first pressing plate 14 for fixing a plurality of the first single channels 13, a first main body bracket 15 for fitting with the first pressing plate 14 to provide rigid support, and a positioning post 16 disposed at the bottom of the first main body bracket 15 for aligning the PCB board and the probe connector. The second probe connection mechanism 12 includes a plurality of second single channels 17 for placing a plurality of test probes 1, a second pressing plate 18 for fixing the plurality of second single channels 17, a second main body bracket 19 for fitting with the second pressing plate 18 to provide rigid support, and a connecting bolt 20 disposed at the bottom of the second main body bracket 19 for fixing the PCB board and the probe connector. The clustering mechanism, which is connected to the first probe connection mechanism 11 and the second probe connection mechanism 12, includes a cover plate 21 that is respectively fitted into the first main body support 15 and the second main body support 19 to seal a plurality of the cables 10. The data acquisition module includes an infrared acquisition component for acquiring temperature distribution images on the surface of the PCB board, and a strain sensor 9 for acquiring spring deformation. The test control module includes, An interface contact quality determination unit is used to determine a resistance variation coefficient based on several contact resistances between the test probe 1 and the test position, so as to determine whether the interface contact quality between the test probe 1 and the test position is qualified according to the resistance variation coefficient. A spring strain determination unit is used to determine the compression state characterization value of the outer conductor spring 5 or the inner conductor spring 6 based on the strain value of the strain sensor 9, and to set several voltage adjustment coefficients to adjust the control voltage of the piezoelectric ceramic sheet according to the comparison result of the compression state characterization value and the preset compression state characterization value. A spring strain correction unit is used to determine the temperature anomaly range based on the temperature distribution image, to determine that the interface contact pressure between the active outer conductor 3 or the active inner conductor 4 and the test position is unqualified based on the temperature anomaly range, and to optimize the voltage regulation coefficient by setting several voltage correction coefficients according to the temperature difference between the highest temperature in the temperature anomaly range and the preset temperature. A strain threshold adjustment unit is used to adjust the preset compression state characterization value based on the optimized frequency of the voltage correction coefficient.

[0025] Specifically, the interface contact quality determination unit determines that the interface contact quality is unqualified based on the comparison result that the resistance variation coefficient is greater than the preset resistance variation coefficient. The interface contact quality determination unit determines that the interface contact quality is qualified based on the comparison result that the resistance variation coefficient is less than or equal to the preset resistance variation coefficient.

[0026] Specifically, strain sensors 9 are embedded inside the steel wires of the outer conductor spring 5 and the inner conductor spring 6, respectively. Precision machining and fiber optic grating (FOR) etching techniques are used to integrate the FOR into the spring steel wires. The spring steel wires are then fabricated into springs. The specific process includes: etching helical grooves on the surface of the spring steel wire using laser micromachining or electrical discharge machining. These grooves provide embedding space for the optical fiber. Simultaneously, mechanical coupling transfers the spring compression strain to the FOR to the fiber grating. The groove depth is 0.13mm–0.3mm, and the width is 0.23mm–0.5mm. The helix angle is designed according to the probe compression stroke, typically 5°–30°. Hollow double-core optical fibers are used; their air cavity structure reduces bending loss and accommodates the small curvature of the spring steel wire. Simultaneously, an excimer laser, such as ArF, is used in conjunction with a phase mask to create periodic refractive index modulation in the fiber core. Finally, the grooves are filled with low-viscosity epoxy resin, such as EPO-TEK. 353ND, after embedding and curing the fiber grating, ensures that the strain of the fiber and the steel wire are synchronized. During the test, when the spring is compressed, the fiber is also subjected to axial strain, which causes the Bragg reflection wavelength to change. Therefore, the compressive strain value of the spring can be calculated based on the Bragg wavelength drift, the initial Bragg wavelength and the material properties of the spring steel wire.

[0027] Specifically, the contact resistance values ​​of the outer and inner moving conductors with the test positions on the PCB board are measured using the four-probe method, also known as the Kelvin four-terminal method. This method uses a design that separates current lines from voltage lines to eliminate interference from lead resistance and accurately measures the resistance value of each contact point. This is existing technology and will not be elaborated further.

[0028] Specifically, the resistance variation coefficient is the percentage of the standard deviation to the average value of several contact resistances, characterizing the degree of fluctuation in the contact resistance between several test probes 1 and the PCB board. A qualified interface contact quality requires that the contact resistance between each probe and the PCB test point be stable and consistent, i.e., "low dispersion," indicating that the fluctuation of the contact resistance is within an acceptable range, the repeatability and consistency of the test results are high, and the contact quality is qualified. If the contact quality is poor, it will lead to significant fluctuations in the contact resistance, i.e., "high dispersion," indicating that the fluctuation of the contact resistance exceeds the normal range, there are a large number of abnormal contact points, the test results are unreliable, and the contact quality is unqualified. In this case, the resistance variation coefficient will increase significantly due to the increase in the standard deviation.

[0029] Specifically, the preset resistance variation coefficient is determined based on the historical test process. Historical test data from at least 1,000 test points with qualified interface contact quality are taken. After cleaning the historical test data, the average value and standard deviation are obtained. The percentage of the standard deviation to the average value is determined as the preset resistance variation coefficient. The selectable range is set to [5%, 10%]. In this embodiment of the invention, 8% is preferred.

[0030] Specifically, when the spring strain determination unit determines that the interface contact quality is unqualified, it sets several voltage adjustment coefficients based on the comparison result between the compression state characterization value and the preset characterization value, so as to increase the control voltage of the piezoelectric ceramic sheet based on the several voltage adjustment coefficients.

[0031] Specifically, the spring strain determination unit determines to increase the control voltage by a first voltage adjustment coefficient based on a comparison result showing that the compression state characterization value is less than a first preset characterization value; The spring strain determination unit determines to increase the control voltage by a second voltage adjustment coefficient based on a comparison result where the compression state characterization value is greater than or equal to the first preset characterization value and less than the second preset characterization value.

[0032] Specifically, the compression state characterization value is the compression deformation of the outer conductor spring 5 or the inner conductor spring 6. The compression deformation of the spring corresponds one-to-one with the contact pressure between the movable outer conductor 3 or the movable inner conductor 4 and the PCB board. The preset characterization value is determined according to the contact pressure required for the test. For example, the required test contact pressure between the movable outer conductor 3 and the PCB board is 100gf-150gf. Based on the required contact pressure value and the material rigidity of the spring, the range of the preset characterization value can be calculated as 2mm-3mm. In practice, the second preset characterization value is taken as the lower limit of the preset characterization value range, which is 2mm. The first preset characterization value is 0.8 times the second preset characterization value, which is 1.6mm. The required test contact pressure between the movable inner conductor 4 and the PCB board is 50gf-100gf. Based on the required contact pressure value and the material rigidity of the spring, the range of the preset characterization value can be calculated as 1mm-2mm. In practice, the second preset characterization value is taken as the lower limit of the preset characterization value range, which is 1mm. The first preset characterization value is 0.8 times the second preset characterization value, which is 0.8mm.

[0033] Specifically, for the active outer conductor 3, the value range of the first voltage adjustment coefficient is set to [1.4, 1.7], preferably 1.5 in this embodiment of the invention, and the value range of the second voltage adjustment coefficient is set to [1.1, 1.3], preferably 1.2 in this embodiment of the invention; for the active inner conductor 4, the value range of the first voltage adjustment coefficient is set to [1.2, 1.4], preferably 1.3 in this embodiment of the invention, and the value range of the second voltage adjustment coefficient is set to [1.05, 1.19], preferably 1.15 in this embodiment of the invention.

[0034] It is understandable that increasing the control voltage of a piezoelectric ceramic sheet can increase its deformation. This is mainly based on the physical mechanism of the inverse piezoelectric effect. When an electric field is applied, the internal lattice structure of the piezoelectric ceramic undergoes polarization reorganization, resulting in mechanical deformation. Increasing the control voltage will directly increase the electric field strength, thereby linearly increasing the deformation.

[0035] Specifically, the spring strain correction unit determines that the interface contact pressure between the active outer conductor 3 and the active inner conductor 4 and the test position is unqualified based on the comparison result that the temperature anomaly range is greater than the first preset range.

[0036] Specifically, the spring strain correction unit determines that the interface contact pressure between the active outer conductor 3 and the test position is unqualified based on the comparison result that the temperature anomaly range is less than or equal to the first preset range and greater than the second preset range.

[0037] Specifically, the spring strain correction unit determines that the interface contact pressure between the active inner conductor 4 and the test position is unqualified based on the comparison result that the temperature anomaly range is less than or equal to the second preset range.

[0038] Specifically, the values ​​of the first preset range and the second preset range are determined based on the diameters of the active outer conductor 3 and the active inner conductor 4 of the test probe 1. The value of the first preset range is the area of ​​a circle that is 1.5 times the diameter of the outer edge of the active outer conductor 3, and the value of the second preset range is the area of ​​a circle that is 2 times the diameter of the active inner conductor 4.

[0039] Specifically, to determine the temperature anomaly range based on the temperature distribution image, the temperature distribution image can be processed into grayscale, and the corresponding temperature can be determined based on the grayscale value. The area where the pixel blocks with temperatures higher than those in the normal test process are connected is determined as the temperature anomaly range.

[0040] Specifically, the infrared acquisition components used to acquire temperature distribution images of the PCB board surface include infrared thermal imagers, such as MiX acoustic thermal imagers, with no specific model or parameters limited.

[0041] Specifically, an unqualified contact pressure between the inner conductor 4 and the test position will lead to a significant increase in contact resistance. Since the inner conductor 4 is the main transmission path of the test signal, the Joule heat generated when the current passes through it is mainly concentrated at the contact point between the probe tip and the test point. Similarly, an unqualified contact pressure between the outer conductor 3 and the test position will also lead to a significant increase in contact resistance, causing the high-frequency signal to be reflected multiple times at the interface. The reflected signal travels back and forth between the outer conductor 3 and the test point, eventually converting into Joule heat. At the same time, the resistance of the outer conductor 3 itself increases due to poor contact, resulting in additional Joule heat generated when the shielding current passes through. The temperature is mainly concentrated in the contact area between the outer conductor 3 and the test point, surrounding the area of ​​the inner conductor 4. When the contact pressures of both the outer conductor 3 and the inner conductor 4 with the test position are unqualified, the heating situation will be more severe, the heat diffusion will be more severe, and the temperature anomaly range will be larger than when the contact pressure between the outer conductor 3 and the test position is unqualified.

[0042] Specifically, when the interface contact pressure is determined to be unqualified, the spring strain correction unit sets several voltage correction coefficients based on the comparison result between the temperature difference and the preset difference, so as to optimize the voltage regulation coefficient based on the several voltage correction coefficients.

[0043] Specifically, the spring strain correction unit determines to optimize the voltage regulation coefficient with a first voltage correction coefficient based on the comparison result that the temperature difference is greater than a first preset difference. The spring strain correction unit determines to optimize the voltage regulation coefficient with a second voltage correction coefficient based on the comparison result that the temperature difference is less than or equal to the first preset difference and greater than the second preset difference.

[0044] Specifically, the temperature difference is the difference between the highest temperature within the abnormal temperature range and the preset temperature. The preset temperature is the highest temperature tested under the condition that the contact pressure is qualified, and the selectable range is set to [30℃, 50℃]. In this embodiment of the invention, 30℃ is preferred.

[0045] Specifically, the preset difference value is determined based on the historical testing process. At least 300 test points are selected where the contact pressure changes from unqualified to qualified after voltage adjustment. The mode and average temperature of each test point are determined. The difference between the mode and the preset temperature is determined as the first preset difference value, and the difference between the average temperature and the preset temperature is determined as the second preset difference value. The selectable range of the second preset difference value is set to [10℃, 30℃], and 15℃ is preferred in this embodiment of the invention. The selectable range of the first preset difference value is set to [20℃, 50℃], and 35℃ is preferred in this embodiment of the invention.

[0046] Specifically, for the active outer conductor 3, the value range of the first voltage correction coefficient is set to [1.18, 1.25], preferably 1.2 in this embodiment of the invention, and the value range of the second voltage correction coefficient is set to [1.14, 1.17], preferably 1.16 in this embodiment of the invention; for the active inner conductor 4, the value range of the first voltage correction coefficient is set to [1.11, 1.15], preferably 1.13 in this embodiment of the invention, and the value range of the second voltage correction coefficient is set to [1.03, 1.1], preferably 1.05 in this embodiment of the invention.

[0047] Specifically, the strain threshold adjustment unit determines to adjust the preset compression state characterization value based on the comparison result that the optimized frequency is greater than the preset frequency; The strain threshold adjustment unit determines not to adjust the preset compression state characterization value based on the comparison result that the optimized frequency is less than or equal to the preset frequency.

[0048] It is understandable that stiffness is an inherent property of springs, determined by the elastic modulus and geometric parameters of the material. When a spring becomes fatigued or ages due to repeated compression, its stiffness will gradually decrease. If the compression remains constant, according to Hooke's Law, the contact pressure will decrease linearly as the stiffness decreases. Therefore, when it is found that the control voltage of the piezoelectric ceramic sheet needs to be corrected frequently, it is necessary to adjust the preset compression state characterization value to improve the judgment criterion for whether the interface contact quality is qualified.

[0049] Specifically, the optimization frequency is the percentage of the number of optimized test probes to the total number of test probes.

[0050] Specifically, the preset frequency is determined based on historical testing processes. Test data from at least 30 test batches are taken to determine the average value and standard deviation of the optimized frequency under normal testing conditions. The preset frequency is the sum of the average value and three times the standard deviation, and the selectable range is set to [15%, 30%]. In this embodiment of the invention, 20% is preferred.

[0051] Specifically, the strain threshold adjustment unit sets several threshold adjustment coefficients based on the frequency difference between the optimized frequency and the preset frequency, so as to increase the preset compression state characterization value according to the several threshold adjustment coefficients.

[0052] Specifically, the strain threshold adjustment unit determines to increase the preset compression state characterization value by a first threshold adjustment coefficient based on the comparison result that the frequency difference is greater than the preset frequency difference. The strain threshold adjustment unit determines to increase the preset compression state characterization value by a second threshold adjustment coefficient based on the comparison result that the frequency difference is less than or equal to the preset frequency difference.

[0053] Specifically, the preset frequency difference value range is set to [3%, 8%], and preferably 5% in this embodiment of the invention; for the active outer conductor 3: the value range of the first threshold adjustment coefficient is set to [1.17, 1.23], and preferably 1.21 in this embodiment of the invention; the value range of the second threshold adjustment coefficient is set to [1.1, 1.16], and preferably 1.12 in this embodiment of the invention; for the active inner conductor 4: the value range of the first threshold adjustment coefficient is set to [1.12, 1.19], and preferably 1.18 in this embodiment of the invention; the value range of the second threshold adjustment coefficient is set to [1.07, 1.11], and preferably 1.09 in this embodiment of the invention.

[0054] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A probe connector device for PCB board connection testing, characterized in that, include: The data acquisition module includes an infrared acquisition component for acquiring temperature distribution images on the surface of the PCB board, and a strain sensor for acquiring spring deformation. The test control module includes, An interface contact quality determination unit is used to determine a resistance variation coefficient based on several contact resistances between a test probe and a test position, so as to determine whether the interface contact quality between the test probe and the test position is qualified according to the resistance variation coefficient. A spring strain determination unit is used to determine the compression state characterization value of the outer conductor spring or the inner conductor spring based on the strain value of the strain sensor, and to set several voltage adjustment coefficients to adjust the control voltage of the piezoelectric ceramic sheet according to the comparison result of the compression state characterization value and the preset compression state characterization value. A spring strain correction unit is used to determine the temperature anomaly range based on the temperature distribution image, to determine that the interface contact pressure between the active outer conductor or the active inner conductor and the test position is unqualified based on the temperature anomaly range, and to optimize the voltage regulation coefficient by setting several voltage correction coefficients according to the temperature difference between the highest temperature in the temperature anomaly range and the preset temperature. A strain threshold adjustment unit is used to adjust the preset compression state characterization value based on the optimized frequency of the voltage correction coefficient.

2. The probe connector device for PCB board connection testing according to claim 1, characterized in that, The probe connector device further includes: A test probe includes a movable outer conductor for shielding signals, an outer conductor spring for extending and retracting the movable outer conductor, a first piezoelectric ceramic plate coaxially mounted with the outer conductor spring, a movable inner conductor coaxially mounted with the movable outer conductor for establishing an electrical connection, an inner conductor spring for extending and retracting the movable inner conductor, and a second piezoelectric ceramic plate coaxially mounted with the inner conductor spring, wherein strain sensors are embedded inside the steel wires of the outer conductor spring and the inner conductor spring, respectively. The probe connection mechanism includes a first probe connection mechanism and a second probe connection mechanism. The first probe connection mechanism includes a plurality of first single channels for placing a plurality of test probes, a first pressing plate for fixing a plurality of the first single channels, a first main body bracket that fits into the first pressing plate to provide rigid support, and a positioning post disposed at the bottom of the first main body bracket for aligning the PCB board and the probe connector. The second probe connection mechanism includes a plurality of second single channels for placing a plurality of test probes, a second pressing plate for fixing a plurality of the second single channels, a second main body bracket that engages with the second pressing plate to provide rigid support, and connecting bolts disposed at the bottom of the second main body bracket for fixing the PCB board and the probe connector.

3. The probe connector device for PCB board connection testing according to claim 1, characterized in that, The interface contact quality determination unit determines that the interface contact quality is unqualified based on the comparison result that the resistance variation coefficient is greater than the preset resistance variation coefficient. The interface contact quality determination unit determines that the interface contact quality is qualified based on the comparison result that the resistance variation coefficient is less than or equal to the preset resistance variation coefficient.

4. The probe connector device for PCB board connection testing according to claim 3, characterized in that, When the spring strain determination unit determines that the interface contact quality is unqualified, it sets several voltage adjustment coefficients based on the comparison result between the compression state characterization value and the preset characterization value, so as to increase the control voltage of the piezoelectric ceramic sheet based on the several voltage adjustment coefficients.

5. The probe connector device for PCB board connection testing according to claim 4, characterized in that, The spring strain correction unit determines, based on the comparison result that the temperature anomaly range is greater than the first preset range, that the interface contact pressure between the active outer conductor and the active inner conductor and the test position is unqualified.

6. The probe connector device for PCB board connection testing according to claim 4, characterized in that, The spring strain correction unit determines that the interface contact pressure between the active outer conductor and the test position is unqualified based on the comparison result that the temperature anomaly range is less than or equal to the first preset range and greater than the second preset range.

7. The probe connector device for PCB board connection testing according to claim 4, characterized in that, The spring strain correction unit determines that the interface contact pressure between the active inner conductor and the test position is unqualified based on the comparison result that the temperature anomaly range is less than or equal to the second preset range.

8. The probe connector device for PCB board connection testing according to claim 5, 6, or 7, characterized in that, When the interface contact pressure is determined to be unqualified, the spring strain correction unit sets several voltage correction coefficients based on the comparison result between the temperature difference and the preset difference, so as to optimize the voltage regulation coefficient based on the several voltage correction coefficients.

9. The probe connector device for PCB board connection testing according to claim 1, characterized in that, The strain threshold adjustment unit determines to adjust the preset compression state characterization value based on the comparison result of the optimized frequency being greater than the preset frequency.

10. The probe connector device for PCB board connection testing according to claim 9, characterized in that, The strain threshold adjustment unit sets several threshold adjustment coefficients based on the frequency difference between the optimized frequency and the preset frequency, so as to increase the preset compression state characterization value according to the several threshold adjustment coefficients.

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