PCB (Printed Circuit Board) deformation compensation method, system and terminal

Abstract

The invention belongs to the technical field of PCB detection, and particularly relates to a PCB deformation compensation method and system and a terminal.The method achieves efficient correction of PCB deformation through a two-point global linear compensation algorithm, and specifically comprises the steps that theoretical coordinates of two alignment points are obtained, and the theoretical distance is calculated; performing alignment through a visual system to obtain a mechanical position containing a probe angle parameter; calculating an actual deformation distance based on a kinematics formula, and determining a deformation proportion; and finally, uniformly compensating all the bonding pad coordinates. According to the method, the overall deformation compensation of the PCB can be completed only through two alignment points, compared with a traditional multi-area compensation method, the process is remarkably simplified, meanwhile, the positioning precision is improved by introducing probe motion parameters, the method can be widely applied to PCB detection equipment such as a flying probe detection machine and an automatic impedance testing machine, and the problem of test deviation caused by PCB deformation is effectively solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of PCB detection, and particularly relates to a PCB board deformation compensation method, system and terminal. Background Art

[0002] In the prior art, during the manufacturing process of a PCB board, due to thermal expansion or contraction, there will be a deviation between the actual pad position and the designed coordinate, which affects the test accuracy of the flying probe tester. To solve this problem, traditional methods such as CN103747617A proposed a partition compensation scheme, which divides the PCB board into multiple regions, sets reference targets in each region, and performs independent compensation by measuring the deformation values of each region. In addition, some detection devices use mechanical positioning or optical alignment technology, but usually only correct local positions and cannot globally adapt to the overall deformation of the PCB board. Although these methods can improve the accuracy to a certain extent, they rely on complex multi-region measurements, have low implementation efficiency, and are difficult to meet the real-time requirements of high-precision detection devices.

[0003] However, the prior art has obvious defects including: the partition compensation method requires a large number of reference targets and multiple measurements, resulting in cumbersome operations and high costs; at the same time, it assumes that the deformation of the PCB board is uneven and ignores the possibility of overall uniform deformation, and the compensation process is complex and computationally intensive. In addition, the traditional scheme does not consider the probe movement characteristics (such as angle deviation) of the flying probe tester, resulting in a deviation between the compensation result and the actual mechanical position, and still may cause problems such as poor probe contact. Therefore, there is an urgent need for an efficient and accurate PCB deformation compensation method to simplify the process and improve the test reliability of the flying probe tester. Summary of the Invention

[0004] The purpose of the present invention is to provide a PCB board deformation compensation method, system and terminal, which can efficiently correct the deviation between the actual position and the theoretical coordinate of the pad caused by the overall deformation of the PCB board in the flying probe tester through a simplified two-point global linear compensation method.

[0005] The present invention realizes the above purpose through the following technical solutions:

[0006] In the first aspect, the present invention proposes a PCB board deformation compensation method, which is applied to a test terminal equipped with a test probe, a alignment vision system and a test probe movement control system. The method includes:

[0007] Obtain the theoretical position coordinates of at least two alignment points on the PCB board, and calculate the theoretical distance between the two alignment points;

[0008] Obtain the mechanical position coordinates of the two alignment points after alignment through the vision system;

[0009] Determine the actual deformation distance based on the mechanical position coordinates of two alignment points;

[0010] Determine the PCB deformation ratio according to the deformation distance;

[0011] Compensate the position of any pad on the PCB according to the deformation ratio to obtain the actual position coordinates of the compensated pad position.

[0012] Further, the obtaining of the theoretical position coordinates of at least two alignment points on the PCB and the calculation of the theoretical distance between the two alignment points include:

[0013] Obtain the theoretical position coordinates (px 1 , py 1 ) and (px 2 , py 2 ) of at least two alignment points on the PCB by loading the PCB data, and calculate the theoretical distance:

[0014] Horizontal theoretical distance: Δpx = px 2 - px 1 ;

[0015] Vertical theoretical distance: Δpy = py 2 - py 1 .

[0016] Further, the mechanical position coordinates are obtained in real time through the test probe motion control system, specifically (mx 1 , α 1 ) and (mx 2 , α 2 ), where α 1 and α 2 are the deflection angles of the test probe relative to the X-axis of the mechanical coordinate system.

[0017] Further, the determining of the actual deformation distance based on the mechanical position coordinates of two alignment points includes:

[0018] Calculate the horizontal actual distance: Δmx = (mx 2 - mx 1 ) + L · [cos(α 2 - cos(α 1 )];

[0019] Calculate the vertical actual distance: Δmy = L · [sin(α 2 ) - sin(α 1 )];

[0020] Where L is the fixed length of the test probe.

[0021] Further, determining the deformation ratio of the PCB board according to the deformation distance includes:

[0022] Calculating the deformation ratio in the horizontal direction: Kx = (Δmx - Δpx) / Δpx;

[0023] Calculating the deformation ratio in the vertical direction: Ky = (Δmy - Δpy) / Δpy.

[0024] Further, compensating any pad position on the PCB board according to the deformation ratio to obtain the actual position coordinates of the compensated pad position includes:

[0025] Compensating the theoretical coordinates (px, py) of any pad on the PCB board to calculate the actual position coordinates (x, y):

[0026] x = px 1 +(px - px 1 )·Kx;

[0027] y = py 1 +(py - py 1 )·Ky.

[0028] Further, the method further includes: the test probe motion control system controls the test probe to align according to the compensated actual position coordinates (x, y).

[0029] In a second aspect, the present invention provides a PCB board deformation compensation system for performing the PCB board deformation compensation method described in any one of the above, and the system includes:

[0030] A data acquisition module for acquiring the theoretical position coordinates of at least two alignment points on the PCB board and acquiring the mechanical position coordinates after the two alignment points perform alignment;

[0031] A distance calculation module for calculating the theoretical distance between two alignment points and determining the actual deformation distance based on the mechanical position coordinates of the two alignment points;

[0032] A compensation calculation module for determining the deformation ratio of the PCB board according to the deformation distance, compensating any pad position on the PCB board according to the deformation ratio, and obtaining the actual position coordinates of the compensated pad position;

[0033] A control module for controlling the test probe to align according to the compensated actual position coordinates.

[0034] In a third aspect, the present invention provides a terminal, including the PCB board deformation compensation system as described above, and a processor and a memory for executing the instructions of the system.

[0035] Further, the terminal is any one of a flying probe tester, a PCB via inspection machine, and an automatic impedance tester, or a PCB detection device integrated with a PCB board detection function.

[0036] The beneficial effects of the present invention are as follows:

[0037] 1. Through the two-point global linear compensation algorithm, the present invention significantly simplifies the process of PCB deformation compensation. The traditional method requires dividing multiple regions and setting a large number of reference points, while the present invention only needs two alignment points to complete the deformation compensation of the entire PCB board, greatly reducing the measurement and calculation time. By introducing the kinematic parameters of the probe angle and mechanical coordinates, a more accurate deformation ratio calculation is achieved, making the compensation result more in line with the actual deformation situation. This method not only reduces the hardware complexity but also improves the operating efficiency of the flying probe tester, and is particularly suitable for high-precision and high-speed test requirements.

[0038] 2. The present invention effectively improves the test accuracy and reliability of the flying probe tester. Through the global linear compensation algorithm, it can accurately correct the pad position deviation caused by the overall deformation of the PCB, ensuring the precise contact between the probe and the pad. Compared with the traditional partition compensation method, the present invention avoids the cumulative error introduced by regional division and local measurement, and the compensation result is more uniform and stable. In addition, this method can be extended and applied to devices such as automatic impedance testers and PCB via inspection machines, and has wide applicability and promotion value. Description of the Drawings

[0039] Figure 1 It is a schematic flow chart of a PCB board deformation compensation method in Embodiment 1 of the present application;

[0040] Figure 2 It is another schematic flow chart of a PCB board deformation compensation method in Embodiment 1 of the present application;

[0041] Figure 3 It is a schematic diagram of the geometric relationship between the theoretical position coordinates and the actual position coordinates of the PCB board in the present application. Detailed Embodiments

[0042] The following further describes the present application in detail with reference to the drawings. It is necessary to point out here that the following detailed embodiments are only used to further illustrate the present application and should not be construed as limiting the protection scope of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0043] Embodiment 1

[0044] As Figures 1-3As shown in the figure, this embodiment proposes a method for compensating PCB board deformation, which is applied to a test terminal equipped with test probes, a alignment vision system, and a test probe motion control system. The specific implementation method includes:

[0045] First, obtain the theoretical position coordinates of at least two alignment points on the PCB board. These theoretical position coordinates are usually obtained based on the design file of the PCB board (such as a Gerber file), representing the theoretical positions of the pads in the design state. In this embodiment, we assume that two alignment points A and B are selected, and their theoretical position coordinates are (px1, py1) and (px2, py2) respectively.

[0046] Next, align these two alignment points through a vision system (such as the CCD camera system of a flying probe tester) to obtain their mechanical position coordinates after alignment. These mechanical position coordinates represent the actual positions of alignment points A and B on the actual PCB board after thermal expansion or contraction. Assume that the mechanical position coordinates of alignment points A and B after alignment are (mx1, α1) and (mx2, α2), where mx1 and mx2 represent the actual positions in the horizontal direction, and α1 and α2 represent the deflection angles of the probe relative to the X-axis of the mechanical coordinate system.

[0047] Then, based on the mechanical position coordinates of these two alignment points, calculate the actual deformation distance. Since the deformation of the PCB board may be non-uniform, but this embodiment assumes that the deformation is uniform (i.e., overall expansion or contraction), so the deformation degree can be estimated by calculating the difference between the actual distance and the theoretical distance between the two alignment points. The actual deformation distance can be calculated by kinematic formulas. Considering the deflection angle of the probe, a more accurate result can be obtained. According to the deformation distance, determine the deformation ratio of the PCB board. The deformation ratio is the ratio of the actual deformation distance to the theoretical distance, which represents the degree of overall deformation of the PCB board.

[0048] Finally, compensate the position of any pad on the PCB board according to the deformation ratio. Specifically, for the theoretical position coordinates (px, py) of each pad, adjust it by the deformation ratio to obtain the compensated actual position coordinates (px', py'). In this way, it can be ensured that the probe of the flying probe tester can accurately contact the pad position on the actual PCB board.

[0049] Further preferably, obtaining the theoretical position coordinates of at least two alignment points on the PCB board and calculating the theoretical distance between the two alignment points includes: obtaining the theoretical position coordinates (px 1 , py 1 ) and (px 2 , py 2 ) on the PCB board by loading PCB board data, and calculating the theoretical distance:

[0050] Horizontal theoretical distance: Δpx = px 2 -px 1 ;

[0051] Vertical theoretical distance: Δpy = py 2 -py 1 。

[0052] Further preferably, the mechanical position coordinates are obtained in real time through the test probe motion control system, specifically as (mx 1 , α 1 ) and (mx 2 , α 2 ), where α 1 and α 2 are the deflection angles of the test probe relative to the X-axis of the mechanical coordinate system.

[0053] Further preferably, determining the actual deformation distance based on the mechanical position coordinates of two alignment points includes:

[0054] Calculating the actual horizontal distance: Δmx = (mx 2 -mx 1 ) + L·[cos(α 2 -cos(α 1 )];

[0055] Calculating the actual vertical distance: Δmy = L·[sin(α 2 ) - sin(α 1 )];

[0056] where L is the fixed length of the test probe.

[0057] Further preferably, determining the PCB board deformation ratio according to the deformation distance includes:

[0058] Calculating the horizontal deformation ratio: Kx = (Δmx - Δpx) / Δpx;

[0059] Calculating the vertical deformation ratio: Ky = (Δmy - Δpy) / Δpy.

[0060] Further preferably, compensating any pad position on the PCB board according to the deformation ratio to obtain the actual position coordinates of the compensated pad position, including: compensating the theoretical coordinates (px, py) of any pad on the PCB board and calculating the actual position coordinates (x, y):

[0061] x = px 1 +(px - px 1 )·Kx;

[0062] y = py 1+(py - py 1 )·Ky。

[0063] Further preferably, the method further includes: controlling the test probe to perform alignment by testing the actual position coordinates (x, y) after the response compensation of the probe motion control system.

[0064] In this embodiment, the two - point global linear compensation algorithm realizes the efficient correction of PCB deformation through the following steps: First, obtain the theoretical coordinates (px 1 , py 1 ) and (px 2 , py 2 ) of two alignment points on the PCB board and calculate the theoretical distance (Δpx, Δpy); then use the vision system for alignment and record the corresponding mechanical positions (mx 1 , α 1 ) and (mx 2 , α 2 ), which include the X - axis coordinate and deflection angle of the probe; then calculate the actual deformation distances Δmx = (mx 2 - mx 1 ) + L·[cos(α 2 - cos(α 1 )] and Δmy = L·[sin(α 2 ) - sin(α 1 )] through the kinematic formula, where L is the probe length; then determine the deformation ratios Kx = (Δmx - Δpx) / Δpx and Ky = (Δmy - Δpy) / Δpy; finally, uniformly compensate all pad coordinates based on this ratio to obtain the actual positions x = px 1 +(px - px 1 )·Kx and y = py 1 +(py - py 1 )·Ky. This algorithm can achieve precise compensation for the overall deformation of the PCB with only two alignment points, avoiding the complexity of traditional multi - region compensation, and significantly improving the positioning accuracy of flying probe testing by introducing probe motion parameters.

[0065] Embodiment 2

[0066] This embodiment proposes a PCB board deformation compensation system for performing the PCB board deformation compensation method as in Embodiment 1. This terminal integrates the above - mentioned PCB board deformation compensation algorithm and compensation system. The system includes:

[0067] A data acquisition module, configured to acquire the theoretical position coordinates of at least two alignment points on the PCB board, and acquire the mechanical position coordinates after alignment of the two alignment points; these coordinate data can be acquired in real time through the vision system and the test probe motion control system of the flying probe tester.

[0068] A distance calculation module is used to calculate the theoretical distance between two alignment points and determine the actual deformation distance based on the mechanical position coordinates of the two alignment points. The theoretical distance can be obtained by calculating the difference between the theoretical position coordinates of the two alignment points, and the actual deformation distance can be calculated through kinematic formulas and the deflection angle of the probe.

[0069] A compensation calculation module is used to determine the deformation ratio of the PCB board according to the deformation distance, and compensate any pad position on the PCB board according to the deformation ratio to obtain the actual position coordinates of the compensated pad position.

[0070] A control module is used to control the test probe to perform alignment in response to the actual position coordinates after compensation. The control module can receive the compensated pad position coordinates output by the compensation calculation module, and control the test probe of the flying probe tester to move to the corresponding position for alignment and testing.

[0071] It should be noted here that each module in the above PCB board deformation compensation system corresponds to each step in the PCB board deformation compensation system of Embodiment 1. The examples and application scenarios implemented by multiple modules and the corresponding steps are the same, but are not limited to the content disclosed in Embodiment 1 above.

[0072] Embodiment 3

[0073] This embodiment proposes a terminal, including a PCB board deformation compensation system as in Embodiment 2, as well as a processor and a memory for executing the system instructions.

[0074] The terminal is any one of a flying probe tester, a PCB via inspection machine, and an automatic impedance tester, or a PCB detection device integrated with PCB board detection functions.

[0075] In this embodiment, it is assumed that the terminal is a flying probe tester. The flying probe tester includes a test probe, an alignment vision system, a test probe motion control system, and the above PCB board deformation compensation system. During the test, the flying probe tester first aligns at least two alignment points on the PCB board through the vision system to obtain their mechanical position coordinates. Then, the PCB board deformation compensation system is used to calculate the deformation ratio and compensate the pad position. Finally, the test probe is controlled to move to the compensated pad position for testing.

[0076] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A PCB board deformation compensation method, characterized in that: Applied to a test terminal having a test probe, an alignment vision system, and a test probe motion control system, the method comprises: Obtain theoretical position coordinates of at least two alignment points on the PCB board, and calculate the theoretical distance between the two alignment points; Acquiring the mechanical position coordinates of the two alignment points after alignment through the visual system; Determine the actual deformation distance based on the mechanical position coordinates of the two alignment points; Determine the deformation ratio of the PCB board according to the deformation distance; The position of any pad on the PCB is compensated according to the deformation ratio to obtain the actual position coordinates of the compensated pad position.

2. A PCB board deformation compensation method according to claim 1, characterized in that: The step of obtaining theoretical position coordinates of at least two alignment points on the PCB board and calculating a theoretical distance between the two alignment points includes: By loading the PCB board data, the theoretical position coordinates (px1, py1) and (px2, py2) of at least two alignment points on the PCB board are obtained, and the theoretical distance is calculated: Theoretical distance in horizontal direction: Δpx=px2-px1; Theoretical distance in vertical direction: Δpy=py2-py1.

3. A PCB board deformation compensation method according to claim 1, characterized in that: The mechanical position coordinates are acquired in real time by the test probe motion control system, specifically (mx1, α1) and (mx2, α2), where α1 and α2 are the deflection angles of the test probe relative to the X-axis of the mechanical coordinate system.

4. A PCB board deformation compensation method according to claim 1, characterized in that: The determining of the actual deformation distance based on the mechanical position coordinates of the two alignment points comprises: Calculate the actual horizontal distance: Δmx = (mx2-mx1) + L [cos(α2-cos(α1)]; Calculate the actual distance in the vertical direction: Δmy = L · [sin (α2) - sin (α1)]; Wherein, L is the fixed length of the test probe.

5. A PCB board deformation compensation method according to claim 1, characterized in that: Determining the deformation ratio of the PCB board according to the deformation distance includes: Calculate the horizontal deformation ratio: Kx = (Δmx-Δpx) / Δpx; Calculate the vertical deformation ratio: Ky = (Δmy-Δpy) / Δpy.

6. A PCB board deformation compensation method according to claim 1, characterized in that: The method of compensating any pad position on the PCB board according to the deformation ratio to obtain the actual position coordinates of the compensated pad position includes: Compensate the theoretical coordinates (px,py) of any pad on the PCB board and calculate the actual position coordinates (x,y): x=px1+(px-px1)·Kx; y=py1+(py-py1)·Ky.

7. A PCB board deformation compensation method according to claim 1, characterized in that: The method further includes: the test probe motion control system controls the test probe to align in response to the compensated actual position coordinates (x, y).

8. A PCB board deformation compensation system, characterized in that: Used to perform the PCB board deformation compensation method according to any one of claims 1 to 7, the system comprises: A data acquisition module is used to acquire theoretical position coordinates of at least two alignment points on the PCB board, and to acquire mechanical position coordinates of the two alignment points after alignment; A distance calculation module is used to calculate the theoretical distance between two alignment points and determine the actual deformation distance based on the mechanical position coordinates of the two alignment points; A compensation calculation module, used to determine the deformation ratio of the PCB board according to the deformation distance, and compensate any pad position on the PCB board according to the deformation ratio to obtain the actual position coordinates of the pad position after compensation; The control module is used to control the test probe to align in response to the actual position coordinates after compensation.

9. A terminal, characterized in that: It comprises the PCB board deformation compensation system as claimed in claim 8, and a processor and a memory for executing instructions of the system.

10. The terminal according to claim 9, characterized in that: The terminal is any one of a flying probe tester, a PCB hole tester, an automatic impedance tester, or a PCB test device integrated with a PCB board test function.

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