A pitch adjustable probe connector device

Abstract

The application relates to the technical field of integrated circuit testing, in particular to a probe connector device with adjustable spacing, which comprises an impedance detection unit, a connector fixing part, a connector rotating part, a single connection port, a signal probe and a grounding probe; an impedance data unit determines the characteristic impedance value of the tested microstrip line based on the data obtained by the signal probe and the grounding probe; a pressure detection unit determines the contact pressure according to the telescopic displacement amount of the signal probe and the grounding probe; a control unit determines the contact pressure allowable range of the probe based on the line width of the microstrip line to be tested and the probe spacing, adjusts the angle between the grounding probe and the PCB surface based on the contact pressure difference between the signal probe and the grounding probe and the line width of the microstrip line, adjusts the contact pressure of the signal probe to obtain the effective characteristic impedance value of the tested microstrip line. The application intelligently adjusts the angle and pressure of the grounding probe, and eliminates the impedance measurement drift problem caused by the imbalance of the double-probe pressure.

Description

Technical Field

[0001] This invention relates to the field of integrated circuit testing technology, and more particularly to a probe connector device with adjustable pitch. Background Technology

[0002] In the field of high-speed circuit design and manufacturing, accurate measurement of characteristic impedance is a core element in ensuring signal integrity. Traditional methods rely on impedance coupons as an evaluation basis, simulating actual trace characteristics through the design of independent test structures. However, impedance coupons differ significantly from the actual traces within the PCB board: First, impedance coupons are usually located in non-functional areas at the board edge, and their trace spacing, line width, and dielectric environment cannot reproduce the complex stack-up structure inside high-density multilayer boards; Second, due to limitations in etching uniformity, material dielectric constant fluctuations, and interlayer lamination tolerances, impedance coupons cannot reflect the actual impedance distribution within the board; Third, as electronic devices develop towards miniaturization and high frequency, applications such as 5G communication and AI chips require impedance control accuracy of ±3% or even ±1%, while the deviation introduced by impedance coupons due to factors such as positional offset and reference layer discontinuity can be as high as ±10%, far exceeding the current process tolerance range. Although time domain reflectometers (TDRs) can directly locate impedance change points by emitting step pulses and analyzing the reflected waveforms, their commercial probes are mostly fixed-pitch structures, which are difficult to adapt to the diversity of pad spacing at the end of differential traces. Furthermore, existing technologies have not solved the potential interference of probe contact pressure on measurement accuracy.

[0003] Currently, TDR measurement faces two major bottlenecks: First, the spacing of differential trace end connection points (such as BGA pads and gold fingers) dynamically changes with package type, making it impossible for fixed probes to achieve fully compatible detection. Second, uneven probe contact pressure introduces additional impedance disturbances; insufficient pressure leads to increased contact resistance, while excessive pressure causes microstrip line deformation. Furthermore, the pressure difference between the signal pin and the ground pin can disrupt the symmetry of the measurement loop, causing ringing distortion in the reflected signal. These two problems are particularly prominent when measuring high-precision impedance boards: spacing mismatch creates detection blind zones, and pressure fluctuations cause impedance reading drift of ±5% or more, restricting yield control and performance verification of high-speed PCBs.

[0004] Chinese Patent Publication No. CN105938160A discloses an impedance testing device, comprising: a switching mounting mechanism; at least three probes, the probes being ground probes or signal probes, the probes being mounted on the switching mounting mechanism, and some or all of the probes being driven by the switching mounting mechanism to switch between a test position and a non-test position; and each time the switching mounting mechanism drives two selected probes to reach the test position in a combination of one signal probe and another signal probe or in a combination of one signal probe and one ground probe, the remaining unselected probes are switched to the non-test position. The aforementioned impedance testing device enables the non-selected probes to be kept away from the circuit board under test when using two selected probes for impedance testing, thus avoiding contact with other parts of the circuit board and preventing interference with the test, ensuring the accuracy of the test results, and preventing short circuits that could damage the measuring instrument. However, the impedance testing device has the following problems: While the device achieves switching between test and non-test positions for the probes through a switching mounting mechanism, effectively preventing accidental contact between the non-test probes and the circuit board under test, thereby preventing short circuits and signal interference, it fails to address the impact of uneven contact pressure between the signal probe and the ground probe on measurement accuracy. This problem stems from the fact that in actual testing, factors such as the contact state between the probe and the circuit board surface, the probe's own stiffness, or installation deviations can lead to inconsistent pressure applied by the signal probe and the ground probe. This pressure difference causes changes in contact resistance, which in turn affects the transmission characteristics of high-frequency signals, causing drift and distortion in the impedance measurement results, especially significant in precision impedance testing. Summary of the Invention

[0005] To address this issue, the present invention provides a probe connector device with adjustable spacing to overcome the problem of uneven probe contact pressure affecting measurement accuracy in the prior art.

[0006] To achieve the above objectives, the present invention provides a probe connector device with adjustable pitch, comprising:

[0007] An impedance detection unit includes a connector fixing part, a connector rotating part connected to the connector fixing part via a rotating shaft assembly, a single connection port disposed at one end of the connector fixing part, a signal probe disposed on the connector fixing part via a first spring assembly, and a grounding probe disposed on the connector rotating part via a second spring assembly, wherein the connector rotating part rotates via the rotating shaft assembly to adjust the distance between the signal probe and the grounding probe.

[0008] An impedance data unit, which is connected to the impedance detection unit through the single connection port, is used to determine the characteristic impedance value of the microstrip line under test based on the data obtained by the signal probe and the ground probe.

[0009] A displacement unit, connected to the impedance detection unit, is used to control the impedance detection unit to move to the target position of the microstrip line to be tested, and to adjust the contact pressure between the signal probe and the ground probe and the microstrip line by controlling the height of the impedance detection unit, so as to perform impedance detection.

[0010] A pressure detection unit, connected to the impedance detection unit, is used to determine the signal probe contact pressure based on the spring extension and retraction displacement of the signal probe, and to determine the ground probe contact pressure based on the spring extension and retraction displacement of the ground probe.

[0011] The control unit, which is connected to the impedance detection unit, the impedance data unit, the pressure detection unit, and the displacement unit respectively, is used to determine the allowable range of probe contact pressure based on the linewidth of the microstrip line under test and the probe spacing, adjust the angle between the ground probe and the PCB board surface based on the contact pressure difference between the signal probe and the ground probe and the linewidth of the microstrip line to reduce the contact pressure difference, and adjust the contact pressure of the signal probe to obtain the effective characteristic impedance value of the microstrip line under test.

[0012] Furthermore, based on the first state, the control unit acquires the first contact pressure difference between the signal probe contact pressure and the ground probe contact pressure, as well as the linewidth of the microstrip line under test, and determines the angle adjustment amount of the ground probe.

[0013] In the first state, the displacement unit uses the height value corresponding to the middle value of the allowable range of the contact pressure of the probe to perform impedance detection.

[0014] Furthermore, the control unit acquires a second contact pressure difference between the signal probe contact pressure and the ground probe contact pressure based on the second state;

[0015] In the second state, the control unit uses the grounding probe with the angle adjusted to perform impedance detection.

[0016] Furthermore, the angle adjustment amount of the grounding probe is positively correlated with the line width, and the angle adjustment amount of the grounding probe is positively correlated with the first contact pressure difference.

[0017] Furthermore, the control unit acquires the drift trend of the impedance detection result based on the second state, and adjusts the contact pressure of the signal probe and the contact pressure of the ground probe according to the drift trend and the second contact pressure difference, so as to obtain the characteristic impedance value of the microstrip line under test after adjustment through the impedance data unit.

[0018] Furthermore, the control unit determines the drift trend based on the contact pressure of several signal probes obtained in the second state and the impedance detection results obtained under the corresponding contact pressure.

[0019] Furthermore, the control unit determines the step size between the contact pressures of each signal probe in the second state according to the allowable contact pressure range, and determines the number of steps for the contact pressure of each signal probe in the second state according to the allowable contact pressure range and the second contact pressure difference, wherein the number of steps is positively correlated with the second contact pressure difference.

[0020] Furthermore, the control unit acquires the effective characteristic impedance value of the microstrip line under test based on the third state;

[0021] The third state involves adjusting the contact pressure of the signal probe based on the drift trend and the second contact pressure difference before performing impedance detection.

[0022] Furthermore, the adjustment direction of the signal probe contact pressure is determined based on the drift trend;

[0023] The adjustment amount of the signal probe contact pressure is positively correlated with the second contact pressure difference.

[0024] Furthermore, the control unit records the signal probe contact pressure in the adjusted third state and corrects the allowable contact pressure range based on the current line width and probe spacing.

[0025] Compared with existing technologies, the advantages of this invention lie in its innovative adjustable-pitch probe structure and intelligent pressure-coordinated control mechanism, which significantly improves the accuracy and adaptability of characteristic impedance measurement for high-speed PCB microstrip lines. By dynamically adjusting the spacing between the signal probe and the ground probe through the rotating shaft assembly, it solves the industry pain point of traditional fixed probes being incompatible with diverse pad spacings. Simultaneously, based on real-time contact pressure detection and feedback control, it intelligently adjusts the angle of the ground probe and the pressure of the signal probe, completely eliminating impedance measurement drift caused by pressure imbalance between the two probes. This design innovatively integrates mechanical adjustment, pressure sensing, and algorithmic control, achieving not only ±1% level high-precision impedance measurement but also significantly expanding the applicability of probe connectors in high-density PCB scenarios such as 5G communication and AI chips, providing reliable assurance for high-speed circuit signal integrity verification.

[0026] Furthermore, this invention effectively suppresses the interference of contact pressure difference on measurement results through the adaptive adjustment mechanism of the rotating shaft drive. Based on the dynamic analysis of the microstrip line width and the initial pressure difference, the rotation angle of the grounding probe is precisely controlled, so that the contact pressure of the two probes tends to be balanced, avoiding microstrip line deformation or abnormal contact resistance caused by uneven pressure distribution, and ensuring the stability of the impedance measurement circuit from the root.

[0027] Furthermore, this invention significantly improves the reliability of characteristic impedance values ​​through drift trend analysis and pressure-coordinated optimization strategies. After angle adjustment, impedance data is collected at multiple pressure points. The pressure-impedance drift law is fitted by an algorithm, and the contact pressure of the signal probe is intelligently corrected by combining residual pressure difference, so that the measurement point is accurately located in the impedance stable range, completely eliminating systematic measurement errors.

[0028] Furthermore, this invention achieves continuous optimization of long-term measurement consistency through a self-correction mechanism of the allowable contact pressure range. The measured and optimized pressure value is fed back to the linewidth-spacing-pressure mapping model to dynamically correct the allowable pressure range boundary, enabling the device to adapt to dynamic factors such as material aging and environmental changes, and ensuring the measurement accuracy of the equipment throughout its entire life cycle.

[0029] Furthermore, this invention combines high compatibility and ease of operation through an integrated elastic probe structure and displacement control unit. The spring assembly enables the probe to adapt to the microstrip surface, and the displacement unit precisely controls the overall height and planar angle, allowing the device to quickly adapt to PCB boards of different thicknesses and curved traces, significantly improving the detection efficiency in complex scenarios. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the adjustable-pitch probe connector device of the present invention.

[0031] Figure 2 This is a schematic diagram illustrating the spacing adjustment of the adjustable probe connector device of the present invention;

[0032] Figure 3 This is an enlarged view of part A of the adjustable-pitch probe connector device of the present invention;

[0033] Figure 4 This is a connection block diagram of the adjustable-pitch probe connector device of the present invention;

[0034] In the figure, 11-connector fixing part; 12-signal probe; 13-first spring assembly; 21-connector rotating part; 22-grounding probe; 23-second spring assembly; 3-rotating shaft assembly; 4-single connection port; 5-microstrip line. Detailed Implementation

[0035] 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.

[0036] 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.

[0037] 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.

[0038] Please see Figure 4 The diagram shown is a connection block diagram of the adjustable-pitch probe connector device of the present invention. The present invention provides an adjustable-pitch probe connector device, comprising:

[0039] An impedance detection unit includes a connector fixing part, a connector rotating part connected to the connector fixing part via a rotating shaft assembly, a single connection port disposed at one end of the connector fixing part, a signal probe disposed on the connector fixing part via a first spring assembly, and a grounding probe disposed on the connector rotating part via a second spring assembly, wherein the connector rotating part rotates via the rotating shaft assembly to adjust the distance between the signal probe and the grounding probe.

[0040] An impedance data unit, which is connected to the impedance detection unit through the single connection port, is used to determine the characteristic impedance value of the microstrip line under test based on the data obtained by the signal probe and the ground probe.

[0041] A displacement unit, connected to the impedance detection unit, is used to control the impedance detection unit to move to the target position of the microstrip line to be tested, and to adjust the contact pressure between the signal probe and the ground probe and the microstrip line by controlling the height of the impedance detection unit, so as to perform impedance detection.

[0042] In one specific embodiment, the displacement unit is driven by a precision ball screw module to move in the XY plane (positioning the target microstrip line). The module is powered by a stepper motor and achieves closed-loop position feedback control through a high-resolution encoder (such as an optical encoder or a magnetic encoder). The module is mounted on a stable base and carries the impedance detection unit to perform two-dimensional planar motion above the PCB board. The positioning accuracy should reach the micrometer level to meet the requirements of precise positioning of the microstrip line pads.

[0043] In one specific embodiment, the displacement unit employs a precision ball screw module to drive Z-axis movement (adjusting contact pressure). This module controls the vertical height of the entire impedance detection unit (or probe section) relative to the PCB board surface. By precisely controlling the Z-axis compression depth, the compression amount of the signal probe and ground probe can be indirectly controlled, thereby adjusting their contact pressure. The Z-axis is also equipped with a high-resolution encoder for closed-loop position control, ensuring the accuracy and repeatability of height (i.e., pressure) adjustment. Force / position hybrid control is a common strategy: first, quickly move to the approach position, then switch to a precise force control mode based on pressure feedback for final contact.

[0044] In one specific embodiment, the displacement unit integrates a high-precision rotary table or a direct-drive rotary motor (θ-axis rotation) between the mounting base of the impedance detection unit and the XYZ motion platform. This rotary axis (θ-axis) drives the entire impedance detection unit to rotate around its vertical axis (Z-axis), ensuring that the perpendicular bisector of the line connecting the signal probe and the ground probe is precisely perpendicular to the PCB board surface. The rotary table is typically driven by a micro servo motor or stepper motor, with torque increased and resolution improved via a harmonic reducer or planetary reducer, and equipped with a high-precision angle encoder (such as a photoelectric encoder) to achieve closed-loop angle control.

[0045] A pressure detection unit, connected to the impedance detection unit, is used to determine the signal probe contact pressure based on the spring extension and retraction displacement of the signal probe, and to determine the ground probe contact pressure based on the spring extension and retraction displacement of the ground probe.

[0046] In one specific embodiment, the pressure detection unit can be implemented using a strain gauge force sensor. Miniature resistance strain gauges (e.g., full-bridge or half-bridge strain gauges configured with a Wheatstone bridge) are precisely attached to the internal support shaft or external load-bearing housing of the first spring assembly (corresponding to the signal probe) and the second spring assembly (corresponding to the grounding probe). When the probe is compressed, causing a slight deformation of the spring assembly, the resistance value of the strain gauge changes accordingly. The axial force (i.e., contact pressure) applied to the probe can be calculated by measuring the unbalanced voltage signal output by the bridge. This solution is technically mature, cost-effective, and highly accurate (up to ±0.5% FS or higher), and is widely used in industrial force measurement.

[0047] In one specific embodiment, the pressure detection unit can also achieve displacement-to-pressure conversion via magnetostrictive effect. A small permanent magnet linked to the probe shaft is placed inside or near the first and second spring assemblies. A linear Hall effect sensor is installed at a corresponding position fixed to the connector fixing / rotating part. Pressure on the probe causes spring compression, which moves the permanent magnet relative to the Hall sensor, changing the magnetic field strength around it. The linear voltage signal output by the Hall sensor is proportional to the displacement of the permanent magnet (i.e., the spring compression). The contact pressure can be accurately calculated based on a pre-calibrated spring stiffness coefficient. This solution is non-contact, frictionless, has a long lifespan, and good anti-interference performance, making it a commonly used method for precision displacement / pressure detection.

[0048] The pressure detection unit includes necessary signal conditioning circuits (such as amplification, filtering, and temperature compensation circuits) and an analog-to-digital converter (ADC) to convert the analog signals (voltage, charge) output by the sensing element into high-precision digital signals.

[0049] The pressure detection unit is connected to the control unit via a standard digital communication interface or an analog voltage output interface, and transmits the measured values ​​of the signal probe contact pressure and the ground probe contact pressure in real time.

[0050] The control unit, which is connected to the impedance detection unit, the impedance data unit, the pressure detection unit, and the displacement unit respectively, is used to determine the allowable range of probe contact pressure based on the linewidth of the microstrip line under test and the probe spacing, adjust the angle between the ground probe and the PCB board surface based on the contact pressure difference between the signal probe and the ground probe and the linewidth of the microstrip line to reduce the contact pressure difference, and adjust the contact pressure of the signal probe to obtain the effective characteristic impedance value of the microstrip line under test.

[0051] Please see Figures 1-3 The figures shown are a structural schematic diagram of the adjustable-pitch probe connector device of the present invention, a pitch adjustment schematic diagram of the adjustable-pitch probe connector device of the present invention, and an enlarged view of part A of the adjustable-pitch probe connector device of the present invention.

[0052] In one specific embodiment, the control unit controls the rotating shaft assembly 3 to rotate the connector rotating part 21 so that the end distance between the signal probe 12 and the ground probe 22 meets the spacing of the microstrip line to be tested; then, the control unit controls the displacement unit to rotate the impedance detection unit until the perpendicular bisector of the line connecting the ends of the signal probe 12 and the ground probe 22 is perpendicular to the PCB board.

[0053] It is understandable that the control unit controls the displacement unit to rotate the impedance detection unit until the perpendicular bisector of the line connecting the ends of the signal probe 12 and the ground probe 22 is perpendicular to the PCB board, so that the descent height of the two probes remains initially consistent when performing impedance detection, thereby reducing the contact pressure difference between the signal probe 12 and the ground probe 22.

[0054] The control unit determines the allowable range of signal probe contact pressure [P] based on the linewidth W of the microstrip line under test and the spacing D between signal probe 12 and ground probe 22 through a preset linewidth-spacing-pressure mapping relationship. min ,P max ], wherein the mapping relationship satisfies:

[0055] ,

[0056] ,

[0057] Wherein, W is the linewidth of the microstrip line under test, in millimeters (mm); D is the distance between signal probe 12 and ground probe 22, in millimeters (mm); k1 is the lower limit proportional coefficient, in Newtons (N), with a value range of 8N to 12N, preferably 10N; k2 is the upper limit proportional coefficient, in Newtons (N), with a value range of 15N to 25N, preferably 20N; b is the pressure offset, in Newtons (N), with a value range of 2N to 5N, preferably 2N.

[0058] It is understood that the linewidth W of the microstrip line under test and the spacing D between the signal probe 12 and the ground probe 22 can be specific data directly input through the input device, or obtained by other testing devices through testing the microstrip line under test on the PCB board. Here, the method by which the control unit obtains the linewidth data and spacing data is not limited.

[0059] It is understandable that the ratio of linewidth to probe spacing directly determines the mechanical stability and electric field distribution characteristics of the microstrip line: when the linewidth is small, the cross-sectional area of ​​the microstrip line decreases, leading to a reduction in compressive strength, requiring a reduction in maximum pressure to avoid plastic deformation; when the probe spacing is small, the electric field coupling between the two probes is enhanced, and excessive contact pressure will expand the contact area between the probe and the copper foil, changing the local capacitance distribution, and thus interfering with the integrity of high-frequency signals. The offset is used to compensate for the inherent stiffness of the probe structure and the minimum contact pressure between the probe and the microstrip line; among them, the upper and lower limit ratio coefficients are calibrated by experiments on the Young's modulus of the copper foil and the dielectric withstand voltage strength, and the offset is calibrated by experiments on the effective pressing of the probe, which will not be elaborated further.

[0060] This invention establishes a quantitative mapping relationship between linewidth, spacing, and pressure, providing a dynamic constraint boundary for contact pressure. This avoids microstrip line deformation or abnormal contact resistance caused by pressure mismatch, ensuring the reliability of impedance measurement from the source and providing a contact pressure reference for the device in subsequent characteristic impedance measurements.

[0061] Specifically, based on the first state, the control unit acquires the first contact pressure difference between the signal probe contact pressure and the ground probe contact pressure, as well as the linewidth of the microstrip line under test, and determines the angle adjustment amount of the ground probe 22.

[0062] In the first state, the displacement unit uses the height value corresponding to the middle value of the allowable range of the contact pressure of the probe to perform impedance detection.

[0063] Specifically, the angle adjustment of the grounding probe 22 is positively correlated with the line width, and the angle adjustment of the grounding probe 22 is positively correlated with the first contact pressure difference.

[0064] In one specific embodiment, the control unit controls the displacement unit to move to the target position of the microstrip line to be tested, and adjusts the distance between the signal probe 12 and the PCB board surface to control its contact pressure. Impedance detection is performed using the height value corresponding to the midpoint of the allowable contact pressure range of the signal probe 12. This is the first state, where the midpoint value is 1 / 2 × (P... min +P max ).

[0065] It is understandable that using the height value corresponding to the middle value of the contact pressure allowable range of the signal probe 12 for impedance detection can simultaneously ensure that both probes are within the contact pressure allowable range, and also provide sufficient adjustment space for subsequent pressure adjustment of the grounding probe 22 and the signal probe 12.

[0066] Based on the first state, the pressure detection unit acquires the contact pressure of the signal probe and the contact pressure of the grounding probe in real time, and calculates the first pressure difference. The specific formula for calculating the first contact pressure difference is as follows:

[0067] ,

[0068] Where △P1 is the first contact pressure difference, in Newtons (N); P s The contact pressure of the signal probe, in Newtons (N); P g The contact pressure of the grounding probe is expressed in Newtons (N).

[0069] Understandably, impedance testing within the allowable range of contact pressure can initially suppress the risk of single-needle overload, but the pressure difference between the two probes will still disrupt the impedance balance of the measurement circuit: the probe on the higher pressure side will have increased parallel capacitance due to the increased contact area, while the probe on the lower pressure side will have increased series impedance due to increased contact resistance. The superposition of the two causes ringing distortion in the reflected signal; the quantization extraction of the first pressure difference provides a key input for subsequent angle compensation, and the signal-to-noise ratio of the TDR waveform is improved by eliminating asymmetrical contact impedance.

[0070] In one specific embodiment, the control unit adjusts the angle between the grounding probe 22 and the PCB board surface to reduce the pressure difference based on the first contact pressure difference ΔP1 and the microstrip line width W. The angle adjustment amount Δθ satisfies:

[0071] ,

[0072] Where △θ is the angle adjustment amount, in degrees (°), and △θ≤1°; k3 is the pressure difference amplification coefficient, in N. -1 The value range is 0.05N. -1 ~0.1N -1 Preferably, k3 is 0.1N. -1 k4 is the line width safety factor, in ° / mm, with a value range of 0.2° / mm to 0.4° / mm. Preferably, k4 is 0.3° / mm.

[0073] Understandably, the pressure difference amplification factor k3 is used to amplify the adjustment angle of the grounding probe 22 according to the magnitude of the first contact pressure difference; the line width safety factor k4 is used to ensure that when the pressure difference is reduced by adjusting the angle of the grounding probe 22, the grounding probe 22 will not deviate from being a microstrip line, and the wider the line width, the larger the adjustment angle; among them, the line width safety factor k4 is calibrated according to the mechanical and geometric models of the grounding probe 22, and the pressure difference amplification factor k3 is calibrated based on several historical experimental data, which will not be elaborated here.

[0074] Furthermore, the angle adjustment direction of the grounding probe 22 is determined based on the sign of the first contact pressure difference. Specifically, when the first contact pressure difference is positive (i.e., the signal probe contact pressure is greater than the grounding probe contact pressure), the control unit controls the rotation direction of the shaft assembly 3 to make the connector rotating part 21 tend to be parallel to the connector fixing part 11; when the first contact pressure difference is negative (i.e., the signal probe contact pressure is less than the grounding probe contact pressure), the control unit controls the rotation direction of the shaft assembly 3 to make the connector rotating part 21 move away from the direction parallel to the connector fixing part 11.

[0075] This invention achieves adjustable probe spacing without increasing hardware complexity by adaptively adjusting the angle of the impedance detection unit, while effectively suppressing contact pressure imbalance caused by uncontrollable factors such as uneven PCB surface or probe assembly tolerances, thus significantly improving the repeatability of impedance measurement.

[0076] Specifically, the control unit acquires a second contact pressure difference between the signal probe contact pressure and the ground probe contact pressure based on the second state;

[0077] In the second state, the control unit uses the grounding probe 22 with the angle adjusted to perform impedance detection.

[0078] In one specific embodiment, the control unit controls the rotating shaft assembly 3 to rotate the connector rotating part 21 according to the angle adjustment amount Δθ and the angle adjustment direction, thereby causing the grounding probe 22 to rotate to the target angle; the calculation formula for the second contact pressure difference is as follows:

[0079] ,

[0080] Where △P2 is the second contact pressure difference, in Newtons (N); P s 'P' represents the contact pressure of the signal probe after angle adjustment, in Newtons (N); g 'This represents the contact pressure of the grounding probe after angle adjustment, in Newtons (N).

[0081] Specifically, the control unit acquires the drift trend of the impedance detection result based on the second state, and adjusts the contact pressure of the signal probe and the contact pressure of the ground probe according to the drift trend and the second contact pressure difference, so as to obtain the characteristic impedance value of the microstrip line under test after adjustment through the impedance data unit.

[0082] Specifically, the control unit determines the drift trend based on the contact pressure of several signal probes obtained in the second state and the impedance detection results obtained under the corresponding contact pressure.

[0083] Specifically, the control unit determines the step size between the contact pressures of each signal probe in the second state according to the allowable contact pressure range, and determines the number of steps for the contact pressure of each signal probe in the second state according to the allowable contact pressure range and the second contact pressure difference, wherein the number of steps is positively correlated with the second contact pressure difference.

[0084] In one specific embodiment, in the second state, the control unit gradually adjusts the contact pressure of the signal probe 12 by means of a preset step size through the displacement unit, and records the characteristic impedance value output by the impedance data unit at each pressure point; based on the recorded contact pressure of several signal probes and their corresponding characteristic impedance values, a linear regression algorithm is used to fit the slope of the impedance value as a function of pressure, and the slope is used as a quantitative indicator of the drift trend.

[0085] Understandably, the angle of the grounding probe 22 has been adjusted in the second state, and the residual pressure difference between the two needles (the second contact pressure difference) has been reduced. However, the slight change in the contact pressure of the signal probe can still cause a systematic shift in the impedance reading. By collecting impedance data at different pressure points and analyzing the overall trend of impedance change with pressure (such as linear increase or decrease), random noise interference can be eliminated, and the inherent law of the pressure-impedance relationship can be accurately captured. This drift trend reflects the sensitivity of contact pressure to impedance measurement and provides a directional basis for subsequent pressure optimization.

[0086] In one specific embodiment, the control unit determines the contact pressure based on the upper limit P of the allowable range. max and lower limit value P min Calculate the pressure adjustment step size ΔP step Satisfying ΔP step =(P max -P min The pressure adjustment steps are calculated based on the second contact pressure difference ΔP2, where N is the fixed number of segments, ranging from 10 to 20. Simultaneously, the pressure adjustment steps n are calculated based on the second contact pressure difference ΔP2, satisfying n = f × ΔP2, where n is the pressure adjustment step number in steps, a positive integer, and 3 steps ≤ n ≤ 10 steps; f is the proportional coefficient, ranging from 3 steps / N to 5 steps / N. Finally, in the second state, the displacement unit is controlled to adjust the pressure by ΔP... step The contact pressure of the signal probe 12 is adjusted n times in increments, and the impedance value is recorded after each adjustment.

[0087] Understandably, the pressure adjustment step size needs to cover the allowable range and avoid inefficiency due to excessive density, so the pressure interval is divided with a fixed number of segments; while the number of adjustment steps needs to adapt to the residual effect of the pressure difference. The larger the second contact pressure difference, the stronger the imbalance of the contact system, and more data points are needed to accurately capture the drift pattern; the setting of the proportional coefficient f ensures that the sampling density is increased when the second contact pressure difference is large, thereby improving the fitting accuracy of the drift trend.

[0088] This invention adjusts the number of sampling steps by dynamically matching the pressure difference, thereby optimizing detection efficiency while ensuring the accuracy of trend analysis and achieving a balance between measurement accuracy and speed.

[0089] Specifically, the control unit acquires the effective characteristic impedance value of the microstrip line under test based on the third state;

[0090] The third state involves adjusting the contact pressure of the signal probe based on the drift trend and the second contact pressure difference before performing impedance detection.

[0091] Specifically, the adjustment direction of the signal probe contact pressure is determined according to the drift trend;

[0092] The adjustment amount of the signal probe contact pressure is positively correlated with the second contact pressure difference.

[0093] In one specific embodiment, the control unit calculates the optimized value of the signal probe contact pressure based on the drift trend and the second contact pressure difference. After the control displacement unit adjusts the signal probe 12 to the pressure value, impedance detection is initiated. At this time, the system is in the third state, and the characteristic impedance value output by the impedance data unit is the effective characteristic impedance value.

[0094] Understandably, the drift trend reveals the regular direction of impedance changes with pressure (e.g., impedance increases or decreases with increasing pressure), while the second contact pressure difference reflects the degree of residual imbalance in the dual-probe contact system. Combining these two factors allows us to determine the optimal pressure operating point: when the drift trend shows that impedance increases with increasing pressure, the pressure should be reduced to bring the reading back to the stable region, and vice versa. At the same time, the larger the residual pressure difference, the stronger the asymmetry of the contact system, requiring a larger pressure compensation to offset its effect. This optimization strategy can simultaneously suppress pressure sensitivity error and contact asymmetry error, placing the measurement point in the flat region of the impedance-pressure curve, where small pressure fluctuations have the least impact on the reading.

[0095] This invention integrates drift trend and pressure difference information to accurately locate the optimal operating point for impedance measurement, enabling a single adjustment to obtain a stable and reliable effective characteristic impedance value.

[0096] In one specific embodiment, the control unit sets the adjustment direction of the signal probe contact pressure to be opposite to the sign of the drift trend (if the trend is positive, the pressure is reduced; if it is negative, the pressure is increased); the adjustment amount is calculated according to the formula Δp=m×|ΔP2|, where m is the pressure compensation coefficient, and the value range is 0.4 to 0.8. Preferably, m is 0.6.

[0097] Understandably, the reverse design of the adjustment direction ensures that the pressure shifts to the stable segment of the drift curve (such as near the zero slope), avoiding entry into the sensitive region; the adjustment amount is proportional to the residual pressure difference because a large pressure difference means that there is a significant imbalance in the contact system, requiring a larger compensation amount to eliminate its influence on the offset of the impedance reading; the value of the pressure compensation coefficient k is based on the calibration of the contact mechanics model, and its physical essence is the compensation strength required per unit pressure difference. This coefficient ensures the correction effect while preventing over-adjustment oscillation.

[0098] This invention achieves precise one-step optimization of contact pressure by quantifying the correlation between residual pressure difference and adjustment range, significantly improving detection efficiency and reliability.

[0099] Specifically, the control unit records the signal probe contact pressure in the adjusted third state and corrects the allowable contact pressure range based on the current line width and probe spacing.

[0100] In one specific embodiment, the control unit records the signal probe contact pressure corresponding to the effective characteristic impedance value obtained after adjustment in the third state, and adjusts the allowable range of the contact pressure [P] based on the current line width W and the probe spacing D. min P max The corrections were made to optimize the pressure reference for subsequent impedance testing of microstrip lines with the same or similar linewidth and spacing combinations.

[0101] Specifically, the signal probe contact pressure value corresponding to the effective characteristic impedance value obtained after adjustment in the third state is first marked as the optimized pressure value P. t ; Calculate the allowable range of the contact pressure [P] min P max The original center point P center , where P center =(P min +P max ) / 2; Calculate the optimized pressure value P t With the original center point P center The deviation δ between them, i.e., δ=P t -P center .

[0102] The deviation amount δ is given by a preset ratio k c As a correction factor η, i.e. η=k c ×δ; where the preset ratio k c The value range is 30% to 50% (i.e., 0.3 ≤ k). c ≤0.5), preferably, k c Take 40%.

[0103] The upper limit of the allowable contact pressure range, P max and lower limit value P min The correction amount η is synchronously shifted to form a new allowable range of contact pressure [P]. min ',P max '],in:

[0104] P min '=P min +η,

[0105] P max '=P max +η,

[0106] The new allowable contact pressure range [P] min ',P max The linewidth W and probe spacing D are associated with the current linewidth W and are stored in or updated in the preset linewidth-spacing-pressure mapping database.

[0107] It is understandable that the optimized pressure value P t This is the optimal operating point verified under actual working conditions (considering specific PCB board surface conditions, probe conditions, environmental factors, etc.) after angle adjustment and pressure co-optimization, reflecting the most stable measurement state for the current specific linewidth W and spacing D combination. The core of the correction process is: respecting the original allowable range [P] calculated based on the initial theoretical model (linewidth-spacing-pressure mapping relationship). min P max This approach effectively incorporates the empirical information gained from this experimental optimization; by calculating the original center point P... center r and P t The deviation δ, and only its preset proportion k is taken. c (30%–50%) is used as the correction amount η, achieving partial compensation rather than completely following the measured value. This strategy effectively suppresses model oscillations: if the correction is completely based on δ (i.e., k... c =100%), a single abnormal measurement or short-term fluctuation may cause a drastic change in the pressure range; while k c The design margin of <50% ensures the gradual and robust nature of the correction, allowing the model to smoothly adapt to long-term changing trends. This adaptive correction mechanism continuously tracks the impact of dynamic factors such as probe elastic decay (material aging) and changes in the friction coefficient caused by environmental temperature and humidity variations on the optimal contact pressure, ensuring that the allowable pressure range always maintains an optimal match with actual working conditions. The preset proportionality coefficient k... c The setting (30%–50%) scientifically balances the model's stability and adaptability requirements: too small a k c (<30%) may lead to overly slow correction, failing to effectively absorb optimization information; an excessively large k cA range greater than 50% may introduce excessive noise, reducing the long-term reliability of the model. By storing the corrected new range in the database, this mechanism ensures continuous optimization of the measurement benchmark throughout the device's lifecycle.

[0108] This invention establishes a self-correction mechanism for the allowable contact pressure range based on measurement data feedback, enabling the device to continuously evolve, significantly improving the consistency and reliability of long-term measurements, and effectively overcoming the problem of decreased measurement accuracy caused by device aging or environmental drift in traditional fixed pressure ranges.

[0109] 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 pitch adjustable probe connector device, characterized by, The application relates to a microstrip line impedance detection device, which comprises the following units: an impedance detection unit, which comprises a connector fixing part, a connector rotating part connected with the connector fixing part through a rotating shaft assembly, a single connection port arranged at one end of the connector fixing part, a signal probe arranged in the connector fixing part through a first spring assembly, and a grounding probe arranged in the connector rotating part through a second spring assembly, wherein the connector rotating part rotates through the rotating shaft assembly to adjust the distance between the signal probe and the grounding probe; an impedance data unit connected with the impedance detection unit through the single connection port, which is used to determine the characteristic impedance value of the tested microstrip line based on the data obtained by the signal probe and the grounding probe; a displacement unit connected with the impedance detection unit, which is used to control the impedance detection unit to move to the target position of the microstrip line to be tested, and to adjust the contact pressure between the signal probe and the grounding probe and the microstrip line through the height adjustment of the impedance detection unit to perform impedance detection; a pressure detection unit connected with the impedance detection unit, which is used to determine the contact pressure of the signal probe according to the spring extension displacement amount of the signal probe, and to determine the contact pressure of the grounding probe according to the spring extension displacement amount of the grounding probe; a control unit connected with the impedance detection unit, the impedance data unit, the pressure detection unit and the displacement unit respectively, which is used to determine the contact pressure allowable range of the probe based on the line width of the microstrip line to be tested and the probe distance, to adjust the angle between the grounding probe and the PCB surface based on the contact pressure difference between the signal probe and the grounding probe and the line width of the microstrip line to reduce the contact pressure difference, and to adjust the contact pressure of the signal probe to obtain the effective characteristic impedance value of the tested microstrip line.

2. The pitch adjustable probe connector apparatus according to claim 1, wherein, The control unit determines the angle adjustment amount of the grounding probe based on the first contact pressure difference between the contact pressure of the signal probe and the contact pressure of the grounding probe and the line width of the tested microstrip line under the first state. The first state is that the displacement unit uses the middle value of the contact pressure allowable range of the probe to perform impedance detection.

3. The pitch adjustable probe connector apparatus according to claim 2, wherein, The control unit obtains the second contact pressure difference between the contact pressure of the signal probe and the contact pressure of the grounding probe under the second state. The second state is that the control unit uses the grounding probe after the angle adjustment to perform impedance detection.

4. The pitch adjustable probe connector apparatus according to claim 3, wherein, The angle adjustment amount of the grounding probe has a positive correlation with the line width, and the angle adjustment amount of the grounding probe has a positive correlation with the first contact pressure difference.

5. The pitch adjustable probe connector apparatus of claim 3, wherein, The control unit obtains the drift trend of the impedance detection result under the second state, adjusts the contact pressure of the signal probe and the contact pressure of the grounding probe according to the drift trend and the second contact pressure difference, and obtains the characteristic impedance value of the tested microstrip line after the adjustment through the impedance data unit.

6. The pitch adjustable probe connector apparatus of claim 5, wherein, The control unit determines the drift trend based on a plurality of signal probe contact pressures obtained under the second state and a plurality of impedance detection results obtained under the corresponding contact pressures.

7. The pitch adjustable probe connector apparatus of claim 6, wherein, The control unit determines a step between the signal probe contact pressures of the second state according to the contact pressure allowable range, and determines a number of steps of the signal probe contact pressures of the second state according to the contact pressure allowable range and the second contact pressure difference, wherein the number of steps is in a positive correlation with the second contact pressure difference.

8. The pitch adjustable probe connector apparatus of claim 7, wherein, The control unit obtains the effective characteristic impedance value of the microstrip line under test based on the third state. The third state is impedance detection after the signal probe contact pressure is adjusted according to the drift trend and the second contact pressure difference.

9. The pitch adjustable probe connector apparatus of claim 8, wherein, The adjustment direction of the signal probe contact pressure is determined according to the drift trend. The adjustment amount of the signal probe contact pressure is in a positive correlation with the second contact pressure difference.

10. The pitch adjustable probe connector apparatus of claim 9, wherein, The control unit records the signal probe contact pressure in the third state after adjustment, and corrects the contact pressure allowable range according to the current line width and the probe spacing.

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