PCB drilling positioning method and system

Abstract

The invention relates to the technical field of PCB drilling positioning, and particularly provides a PCB drilling positioning method and system.The method comprises the steps that structured light pattern images corresponding to different reference mark points are obtained, and the structured light pattern images comprise preset structured light patterns with projection areas covering the reference mark points; for each reference mark point, actual Z-axis height information is obtained according to the structured light pattern image, and then the focusing depth of the laser scanning system is adjusted according to the actual Z-axis height information; for each reference mark point, acquiring original two-dimensional coordinate information of the reference mark point by using a laser scanning system, and then correcting the original two-dimensional coordinate information according to the actual Z-axis height information and preset optical geometric parameters of the laser scanning system to obtain corrected two-dimensional coordinate information; correcting a preset drilling target point position according to all the corrected two-dimensional coordinate information to obtain a final drilling position of the drilling target point; according to the method, the problems of defocusing and projection errors caused by unevenness of the PCB can be effectively solved.

Description

Technical Field

[0001] The present application relates to the technical field of PCB drilling positioning technology, and in particular to a PCB drilling positioning method and system. Background Art

[0002] On automated production lines for printed circuit boards (PCBs), drilling equipment is crucial for achieving electrical interconnection. Existing technology relies on laser scanning positioning technology to determine the drill hole location. Specifically, existing laser scanning positioning technology first identifies the actual position of a fiducial marker, then calibrates the preset drill hole position based on the actual position of the fiducial marker and the preset position. As PCB board materials evolve toward larger, more multi-layered, and ultra-thin substrates, the demand for high-density interconnection and micro-hole processing is growing, necessitating ever-increasing positioning accuracy requirements to accommodate more sophisticated electrical interconnection needs.

[0003] However, during the actual PCB board manufacturing process, the PCB board may accumulate internal stress or undergo slight deformation during production and transportation. This deformation can cause the PCB board surface to be uneven, such as localized warping or depressions on the PCB board surface. When the PCB board is fixed to the drilling equipment, this unevenness causes the reference mark points to be located at different Z-axis heights. Since existing laser scanning positioning technology uses a method of moving the laser scanning head within a preset fixed focal plane or quasi-focal plane for measurement, and the deformation of the PCB board can cause some reference mark points to be outside the fixed focal plane or quasi-focal plane, the laser spot size will change and the reflected signal strength and clarity will be impaired due to the defocus of the reference mark points during the laser scanning process. This will affect the accuracy of image processing algorithms (such as edge detection or center calculation) and introduce measurement errors. In addition, projecting markers of different Z-axis heights onto the same two-dimensional measurement plane will produce projection errors. This error depends on the height difference, the laser incident angle, and the characteristics of the optical components. Under high-speed scanning conditions, these errors are amplified, resulting in systematic deviations in the calculation of the actual position of the reference markers and deviations between the drill position corrected based on the actual position and preset position of the reference markers and the target drill position, which in turn affects the product yield and electrical performance.

[0004] There is no effective technical solution to the above problems. It should be noted that the above information disclosed in this section is only used to understand the background of the present invention, and therefore may contain information that does not constitute prior art. Summary of the Invention

[0005] The purpose of this application is to provide a PCB drilling positioning method and system, which can effectively solve the defocus and projection error problems caused by uneven PCB board materials.

[0006] In a first aspect, the present application provides a PCB drilling positioning method, which comprises the following steps: S1. Acquire structured light pattern images corresponding to different reference mark points, where the structured light pattern images include a preset structured light pattern whose projection area covers the reference mark points; S2. For each reference mark point, obtain the actual Z-axis height information according to the structured light pattern image, and then adjust the focus depth of the laser scanning system according to the actual Z-axis height information; S3. For each reference mark point, use a laser scanning system to obtain the original two-dimensional coordinate information of the reference mark point, and then correct the original two-dimensional coordinate information according to the actual Z-axis height information and the preset optical geometric parameters of the laser scanning system to obtain corrected two-dimensional coordinate information; S4. Correct the preset drilling target point position according to all corrected two-dimensional coordinate information to obtain the final drilling position of the drilling target point.

[0007] In a second aspect, the present application further provides a PCB drilling positioning system, which includes: A structured light pattern image acquisition module is used to acquire structured light pattern images corresponding to different reference mark points, where the structured light pattern images include a preset structured light pattern whose projection area covers the reference mark points; A focus depth adjustment module is used to obtain actual Z-axis height information for each reference mark point based on the structured light pattern image, and then adjust the focus depth of the laser scanning system based on the actual Z-axis height information; A two-dimensional coordinate correction module is used to obtain the original two-dimensional coordinate information of each reference mark point using a laser scanning system, and then correct the original two-dimensional coordinate information based on the actual Z-axis height information and the preset optical geometric parameters of the laser scanning system to obtain corrected two-dimensional coordinate information; The drilling position determination module is used to correct the preset drilling target point position according to all the corrected two-dimensional coordinate information to obtain the final drilling position of the drilling target point.

[0008] As can be seen from the above, the PCB drilling positioning method and system provided by the present application first obtains the actual Z-axis height information of each reference mark point, and uses the actual Z-axis height information to dynamically adjust the focus depth of the laser scanning system, and then uses the laser scanning system after adjusting the focus depth to collect the original two-dimensional coordinate information, and corrects the original two-dimensional coordinate information according to the actual Z-axis height information and optical geometric parameters to effectively solve the defocus and projection error problems caused by the unevenness of the PCB board. Therefore, the present application can effectively solve the problems of laser spot size change, reflected signal intensity and clarity damage caused by defocus of the reference mark point, and avoid systematic deviations in the actual position calculation of the reference mark point and deviations between the drilling position obtained based on the actual position and preset position of the reference mark point and the target drilling position, thereby effectively improving the accuracy of the image processing algorithm, product yield and electrical performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 A flowchart of a PCB drilling positioning method provided in an embodiment of the present application.

[0010] Figure 2 A schematic structural diagram of a PCB drilling positioning system provided in an embodiment of the present application.

[0011] Reference numerals: 1. structured light pattern image acquisition module; 2. focus depth adjustment module; 3. two-dimensional coordinate correction module; 4. drilling position determination module. DETAILED DESCRIPTION

[0012] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work fall within the scope of protection of the present application.

[0013] It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings. At the same time, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description and should not be understood as indicating or implying relative importance.

[0014] First, as Figure 1As shown, the present application provides a PCB drilling positioning method, which includes the following steps: S1. Acquire structured light pattern images corresponding to different reference mark points, where the structured light pattern images include a preset structured light pattern whose projection area covers the reference mark points; S2. For each reference mark point, obtain the actual Z-axis height information according to the structured light pattern image, and then adjust the focus depth of the laser scanning system according to the actual Z-axis height information; S3. For each reference mark point, use a laser scanning system to obtain the original two-dimensional coordinate information of the reference mark point, and then correct the original two-dimensional coordinate information according to the actual Z-axis height information and the preset optical geometric parameters of the laser scanning system to obtain corrected two-dimensional coordinate information; S4. Correct the preset drilling target point position according to all corrected two-dimensional coordinate information to obtain the final drilling position of the drilling target point.

[0015] The structured light pattern image of step S1 includes a preset structured light pattern in which the projection area covers the reference mark point, that is, in the structured light pattern image, the area where the reference mark point is located is covered by the projected pre-structured light pattern, and the preset structured light pattern can adopt any one or more of the following forms: 1. adopting a stripe pattern, such as a sinusoidal stripe or a binary stripe; 2. adopting a dot matrix pattern, such as a regularly arranged dot matrix; 3. adopting a coding pattern, such as a Gray code pattern or a pseudo-random code pattern. Those skilled in the art can select the pattern in the preset structured light pattern according to actual needs. Step S1 can be achieved by obtaining the structured light pattern images corresponding to different reference mark points through the cooperation of an existing digital camera and an existing structured light projector or an existing industrial camera and an existing structured light projector. The structured light projector is used to project a specific pattern onto the area where the reference mark point is located on the PCB board, and the camera is used to capture an image containing the specific pattern.

[0016] Acquiring actual Z-axis height information from the structured light pattern image in step S2 involves analyzing the structured light pattern image to calculate the actual Z-axis height value of each fiducial marker. Step S2 can employ existing triangulation principles, phase measurement profilometry, or stereo vision algorithms to achieve this. For example, depth information (actual Z-axis height information) can be calculated by analyzing the deformation or displacement of the structured light pattern on the object's surface. The principle behind acquiring actual Z-axis height information from the structured light pattern image in step S2 is that when a structured light pattern with known shape and parameters is projected onto an object's surface, if the surface is undulating or uneven, the structured light pattern projected onto the object will deform, and the degree and manner of deformation are directly related to the three-dimensional topography of the object's surface. Specifically, in this embodiment, a camera can be used to capture an image of the projected deformed structured light pattern from a specific angle, and then the three-dimensional topography of the object's surface (including Z-axis height information) can be determined by analyzing the difference between the deformed structured light pattern and the original projected pattern. Therefore, step S2 can acquire actual Z-axis height information from the structured light pattern image. Adjusting the focal depth of the laser scanning system according to the actual Z-axis height information in step S2 refers to dynamically changing the focal length or relative position of the optical components of the laser scanning system according to the actual Z-axis height value of each reference mark point, so that the laser spot remains clearly focused at the current reference mark point. This embodiment can adjust the focal depth of the laser scanning system by adjusting the applied voltage of the piezoelectric ceramic-driven microlens or liquid lens. It should be understood that since step S2 can accurately measure the actual Z-axis height of each reference mark point and dynamically adjust the focal depth of the laser scanning system accordingly, step S2 can enable the laser spot to remain clearly focused on reference marks at different heights, thereby effectively solving the problem of laser spot size change, loss of reflected signal intensity and clarity due to defocusing of the reference mark point, thereby effectively improving the accuracy of the image processing algorithm and avoiding the introduction of measurement errors.

[0017] Acquiring the original two-dimensional coordinate information of the reference marker using a laser scanning system in step S3 refers to the process of scanning the reference marker using the laser scanning system after adjusting the focal depth of the laser scanning system and recording its initial position data on the two-dimensional plane. This embodiment can achieve acquisition of the original two-dimensional coordinate information of the reference marker by detecting the peak intensity of the reflected light signal using a laser sensor or identifying the center of the laser spot using an image processing algorithm to determine the X and Y coordinates of the reference marker. The preset optical geometric parameters in step S3 are optical characteristic parameters inherent to the laser scanning system. These preset optical geometric parameters are used to describe the geometric relationship and optical characteristics of components such as the laser beam, lens, and sensor. These preset optical geometric parameters can be optical characteristic parameters determined by the laser scanning system at the factory or after initial calibration. The corrected 2D coordinate information is the coordinate data of the fiducial marker on the 2D measurement plane obtained by correcting the original 2D coordinate information based on the actual Z-axis height information and preset optical geometric parameters. When the laser scanning system scans these markers at different Z-axis heights and obtains their 2D coordinates, the markers at different Z-axis heights will have different projection positions on the 2D measurement plane due to the influence of the incident angle of the laser beam and the projection characteristics of the optical system. This means that the original 2D coordinate information is subject to projection errors. Furthermore, optical elements such as lenses in the laser scanning system may have inherent distortions (e.g., radial distortion or tangential distortion). These distortions can also cause deviations between the actual and ideal positions of points on the image and affect the accuracy of the original 2D coordinates. Therefore, this embodiment can correct the original 2D coordinate information based on the actual Z-axis height information and preset optical geometric parameters to effectively reduce the projection errors of the original 2D coordinate information and improve the accuracy of the 2D coordinate corrections. This effectively avoids systematic deviations in the actual position calculation of the fiducial markers and deviations between the drill hole positions corrected based on the actual and preset positions of the fiducial markers and the target drill hole positions.Taking the original two-dimensional coordinate information of a certain reference mark point and its corresponding actual Z-axis height information as an example, the correction process of step S3 can be carried out as follows: using a distortion model (such as a Brown-Conrady model) to perform distortion correction on the original two-dimensional coordinate information according to a preset lens distortion coefficient to obtain ideal image coordinates without distortion. This step eliminates the image deformation introduced by the optical lens itself; using a three-dimensional to two-dimensional projection model (a model for calculating the precise projection coordinates of the coordinate point on the two-dimensional reference plane based on the three-dimensional spatial position information of the coordinate point (a combination of XOY plane coordinates and Z-axis height) and parameters such as the camera's laser beam incident angle, lens focal length, positions of various optical elements, and position of the image sensor, this model is preferably an existing pinhole camera model) to calculate the corrected position (corrected two-dimensional coordinate information) of the original two-dimensional coordinate on the ideal two-dimensional reference plane based on parameters such as the undistorted ideal image coordinates, actual Z-axis height information, and the camera's current laser beam incident angle, lens focal length, positions of various optical elements, and position of the image sensor.

[0018] The drilling target point positions in step S4 are the locations where drilling is to be performed as preset in the PCB design file. Step S4 is equivalent to obtaining the precisely corrected two-dimensional coordinate information for all fiducial markers and then using this information to perform an overall calibration of the preset drilling target point positions, thereby effectively improving the drilling positioning accuracy and product yield. The specific process of step S4 may include calculating the overall deformation parameters (e.g., translation and rotation) of the PCB board based on the corrected two-dimensional coordinate information for all fiducial markers and their preset positions on the design drawing. For example, using a least squares method or an affine transformation model, the overall translation of the PCB board in the X and Y axes and the rotation angle about a certain center point are derived by comparing the deviations between the actually measured fiducial marker positions and the theoretically designed positions. After calculating these deformation parameters, the calculated deformation parameters are applied to all preset drilling target point positions on the PCB board to correct the drilling target point positions. Specifically, for each preset drilling target point, its original two-dimensional coordinate is shifted according to the calculated translation and rotated according to the calculated rotation.

[0019] The core innovation of this application lies in that it first obtains the actual Z-axis height information of each reference mark point, and uses the actual Z-axis height information to dynamically adjust the focus depth of the laser scanning system, and then uses the laser scanning system after adjusting the focus depth to collect the original two-dimensional coordinate information, and corrects the original two-dimensional coordinate information according to the actual Z-axis height information and optical geometric parameters to effectively solve the defocus and projection error problems caused by the unevenness of the PCB board. Therefore, this application can effectively solve the problems of laser spot size change, reflected signal intensity and clarity damage caused by defocus of the reference mark point, and avoid systematic deviations in the actual position calculation of the reference mark point and deviations between the drilling position corrected based on the actual position and preset position of the reference mark point and the target drilling position, thereby effectively improving the accuracy of the image processing algorithm, product yield and electrical performance.

[0020] This method achieves high-precision drilling positioning by introducing structured light to measure the Z-axis height and dynamically adjusting the focal depth of the laser scanning system. The method then uses the Z-axis height and the optical set parameters of the laser scanning system to correct the two-dimensional coordinate information. The method first obtains a structured light pattern image corresponding to different reference markers. This image contains a preset structured light pattern whose projection area covers the reference markers. This image captures the surface topography information of the reference marker area, laying the foundation for subsequent accurate measurement of the Z-axis height information of the reference markers. Then, for each reference marker, the actual Z-axis height information is obtained based on its corresponding structured light pattern image. Based on the actual Z-axis height information obtained, the focal depth of the laser scanning system is adjusted to ensure that the laser spot remains clearly focused on reference markers at different heights (equivalent to ensuring that the system is in focus when measuring different reference markers), thereby avoiding measurement errors and signal quality degradation caused by defocus. Next, for each fiducial marker, the laser scanning system is used to obtain the original 2D coordinate information of the fiducial marker. This original 2D coordinate information is then corrected based on the actual Z-axis height information and the preset optical geometric parameters of the laser scanning system to effectively eliminate the 2D coordinate projection error introduced by Z-axis height differences and the inherent characteristics of the optical system, thereby effectively improving the accuracy of the 2D coordinates of the fiducial marker. Finally, the preset drilling target point position is corrected based on all corrected 2D coordinate information to obtain the final drilling position of the drilling target point with high precision. This correction process typically involves calculating the translation, rotation, stretching, or shrinkage parameters of the plate, and then applying these parameters to the preset drilling position.

[0021] In some preferred embodiments, the preset structured light pattern is a stripe pattern, a dot pattern or a coded pattern. The stripe pattern of this embodiment refers to a pattern with a periodic or non-periodic stripe structure. The stripe pattern can be a sinusoidal stripe, a square wave stripe or a Gray code stripe, etc. The stripe pattern has the advantages of high information density and relatively strong anti-interference ability, which helps to improve the accuracy of obtaining Z-axis height information. The dot pattern of this embodiment refers to a pattern composed of discrete points. The dot pattern can be a regularly arranged dot matrix or a randomly distributed dot matrix. The dot pattern has the advantages of being relatively simple to calculate and can provide effective measurement points for areas where certain surface features are not obvious, which helps to improve the coverage and accuracy of Z-axis height information. The coded pattern of this embodiment refers to a structured light pattern in which information is embedded in the pattern through a specific coding method. The coded pattern can be a Gray code, an M sequence code or a time code, etc. The coded pattern has the advantages of strong anti-interference ability, a large measurement range, and applicability to complex surfaces, which helps to improve the robustness and accuracy of Z-axis height information acquisition.

[0022] The above-mentioned embodiment proposes obtaining actual Z-axis height information based on a structured light pattern image to adjust the depth of focus of a laser scanning system. This method can specifically calculate the Z-axis height of a reference mark area by analyzing the deformation or positional offset of the structured light pattern projected on the area of ​​the reference mark. For example, for a stripe pattern, the height can be inferred by measuring the curvature or spacing of the stripes, and for a dot pattern, the offset of the dots can be measured. This allows for dynamic focus adjustment based on the actual height information of the PCB surface. However, during this implementation, surface features of the PCB itself, such as texture, color variations, printed characters, or residue, may interfere with the recognition and analysis of the structured light pattern projected thereon, affecting the accuracy of the Z-axis height information extracted from the structured light pattern, and thus affecting the subsequent depth of focus adjustment and the ultimate positioning accuracy.

[0023] In order to solve this technical problem, in some preferred embodiments, step S2 includes: S21. Analyze the surface features of the PCB board on the structured light pattern image for each reference mark point, and then process the structured light pattern image based on the analysis results to reduce the influence of the surface features of the PCB board on the recognition of the preset structured light pattern; S22. For each reference mark point, obtain actual Z-axis height information according to the structured light pattern image, and then adjust the focus depth of the laser scanning system according to the actual Z-axis height information.

[0024] Analyzing the surface features of a PCB board using a structured light pattern image refers to identifying and quantifying visual features in the structured light pattern image that are caused by inherent properties or attachments on the PCB board surface, in addition to the preset structured light pattern itself. This embodiment can use a variety of technologies to implement PCB board surface feature analysis, such as using texture analysis technology to identify fiber texture or copper foil texture on the PCB board surface; using color or grayscale analysis technology to identify areas with ink, characters, or stains on the PCB board surface; and using edge detection or shape recognition technology to locate pads, vias, or component outlines on the PCB board surface. Processing the structured light pattern image based on the analysis results refers to applying corresponding image processing technologies based on the surface feature analysis results to reduce or eliminate the interference of these features on structured light pattern recognition. For example, if specific texture interference is identified, a texture suppression filter can be applied; if high-contrast characters are identified, these areas can be masked or smoothed; if overall brightness unevenness is identified, background correction can be performed. This embodiment can process the structured light pattern image based on the analysis results to make the portion of the image representing the preset structured light pattern clearer, easier to identify and analyze, and effectively reduce interference caused by board surface features. This embodiment can adjust the focus depth of the laser scanning system according to the actual Z-axis height information by first consulting a preset focus depth adjustment table according to the actual Z-axis information to obtain the focus depth adjustment amount, and then adjusting the focus depth of the laser scanning system according to the focus depth adjustment amount. The mapping relationship table stores the focus depth adjustment amounts corresponding to different Z-axis heights. This embodiment can also adjust the focus depth of the laser scanning system according to the actual Z-axis height information by inputting the actual Z-axis height information into a pre-trained machine learning model. The model can determine the distance that needs to be driven to move the laser scanning head along the Z-axis or adjust the position of the zoom lens based on the input Z-axis height information.

[0025] This solution refines the steps of obtaining the actual Z-axis height information based on the structured light pattern image and adjusting the focal depth of the laser scanning system. First, for the structured light pattern image obtained for each reference mark point, before identifying the preset structured light pattern, the image is first analyzed for the surface features of the PCB board. This analysis aims to distinguish which parts of the image are the projected structured light pattern and which parts are the texture, color, characters or other surface defects of the PCB board itself, and based on the analysis results, the structured light pattern image is targeted for processing. For example, if it is found that there are bright or dark stains that affect the continuity of the structured light stripes, the brightness or contrast of these areas are adjusted, or even local repairs are performed. Subsequently, for the processed structured light pattern image, the actual Z-axis height information of the reference mark point is obtained based on the clear structured light pattern information therein. Since the interference caused by the surface features of the board is effectively weakened, this embodiment can obtain the actual Z-axis height information that can more accurately reflect the true height of the reference mark point based on the deformation or position information extracted from the structured light pattern. Finally, the focal depth of the laser scanning system is precisely adjusted based on the more accurate actual Z-axis height information obtained, so that the focal plane of the laser scanning is accurately positioned at the actual height of the reference mark point, thereby ensuring that when the original two-dimensional coordinate information of the mark point is subsequently obtained, the laser spot is in the optimal focus state, and the signal strength and clarity are guaranteed, thereby significantly improving the acquisition accuracy of the original two-dimensional coordinate information.

[0026] As a specific implementation, when analyzing the surface features of a PCB board using a structured light pattern image, Fourier transform analysis can be used to analyze the image's frequency domain characteristics to identify board texture frequencies that differ from the structured light pattern frequency, or methods such as local binary patterns (LBP) can be used to analyze local texture features. When processing the image based on the analysis results, frequency domain filtering (e.g., designing a notch filter) can be used to filter out texture interference at specific frequencies, or spatial domain filtering (e.g., an adaptive filter) can be used to adjust the filter intensity based on local region characteristics. Alternatively, machine learning-based methods can be used to identify and segment characteristic regions on the board surface, and then repair or suppress these regions. When obtaining actual Z-axis height information from the processed structured light pattern image, the actual Z-axis height information can be obtained by using a phase shifting method to calculate the height field by analyzing the phase information of multiple phase-shifted structured light images, or by using a stereo matching method that combines a binocular vision system and the structured light pattern for three-dimensional reconstruction. When adjusting the focus depth of the laser scanning system according to the actual Z-axis height information obtained, the zoom lens group inside the laser scanning head can be controlled to move or the entire laser scanning head can be controlled to move along the Z-axis direction so that the focus of the laser beam falls on the target height plane.

[0027] This embodiment can effectively reduce the interference of the surface features of the PCB board itself on the structured light pattern recognition and the acquisition of Z-axis height information by adding the step of analyzing the surface features of the PCB board on the structured light pattern image and processing it according to the analysis results before obtaining the actual Z-axis height information based on the structured light pattern image. Therefore, this embodiment can obtain more accurate actual Z-axis height information, so as to achieve precise adjustment of the focusing depth of the laser scanning system and ensure that the laser scanning system is in the optimal focusing state when obtaining the original two-dimensional coordinate information of the reference mark point, thereby effectively improving the acquisition accuracy of the original two-dimensional coordinate information, and further effectively improving the positioning accuracy of PCB drilling.

[0028] The aforementioned embodiment proposes obtaining actual Z-axis height information based on a structured light pattern image and adjusting the laser scanning system's depth of focus to address defocus issues caused by uneven PCB surfaces. This actual Z-axis height information can be obtained by analyzing the overall deformation of the structured light pattern to estimate the average height of the fiducial marker area. However, if this implementation fails to fully account for subtle local height variations on the PCB surface and relies solely on overall or average height information, the obtained Z-axis height information may be inaccurate, affecting the accuracy of depth of focus adjustment and ultimately the precision of the original two-dimensional coordinates acquired by the laser scanning.

[0029] In order to solve this technical problem, in some preferred embodiments, step S22 includes: S221. For each reference mark point, locally analyze the structured light pattern image to obtain Z-axis height data of multiple analysis areas, and then use the Z-axis height data corresponding to the analysis area where the reference mark point is located as the actual Z-axis height information; S222. For each reference mark point, adjust the focus depth of the laser scanning system according to the corresponding actual Z-axis height information.

[0030] The specific process of step S221 may be: using a preset division rule (e.g., grid division) to divide the area where the preset structured light pattern is located in the structured light pattern image into multiple independent analysis areas; for each analysis area, analyzing the structured light pattern in the analysis area using triangulation principles, phase measurement profilometry, or a stereo vision algorithm to obtain Z-axis height data corresponding to the analysis area; and using the Z-axis height data corresponding to the analysis area where the fiducial marker is located as the actual Z-axis height information. This embodiment is equivalent to solving the problem of analyzing the entire preset structured light pattern area as a whole and ignoring local height differences within the preset structured light pattern area by performing local analysis on the structured light pattern image. This embodiment can use the Z-axis height data corresponding to the discrete area where the fiducial marker is located as the actual Z-axis height information of the point, ensuring that the obtained actual Z-axis height information accurately reflects the local surface height of the fiducial marker. Therefore, this embodiment can more accurately adjust the focus depth of the laser scanning system corresponding to each fiducial marker based on this more accurate actual Z-axis height information, thereby further reducing the change in spot size and signal quality degradation caused by defocus, thereby further improving the accuracy of the original two-dimensional coordinate information obtained by laser scanning. In addition, this embodiment can provide more accurate local height information and achieve more accurate focusing by combining the aforementioned steps of performing surface feature analysis and processing on the structured light pattern image to reduce interference and the subsequent step of correcting the original two-dimensional coordinates using the actual Z-axis height information, thereby jointly improving the accuracy of the entire PCB drilling positioning method.

[0031] In some preferred embodiments, step S222 includes: A1. For each reference mark, determine the initial focus depth adjustment amount based on the corresponding actual Z-axis height information; A2. Obtain the real-time operating parameters and historical operating data of the laser scanning system; A3. For each reference mark point, adjust the initial focus depth adjustment amount according to the real-time operating parameters and historical operating data to obtain the focus depth adjustment amount, and then adjust the focus depth of the laser scanning system according to the focus depth adjustment amount.

[0032] The initial adjustment amount of the focus depth refers to the focus position adjustment amount for preliminary compensation of defocus, which is calculated based on the actual Z-axis height difference (actual Z-axis height information) of the reference mark point relative to the reference plane. In this embodiment, a calculation method based on an optical geometric model or a pre-calibrated height-focus lookup table can be used to determine the initial adjustment amount of the focus depth. Real-time operating parameters refer to dynamic data reflecting the current working state of the laser scanning system. Such real-time operating parameters may include the internal temperature of the system, the vibration frequency or amplitude of mechanical components, power supply voltage fluctuations, or the real-time response characteristics of optical elements. Historical operating data refers to the operating information and performance records accumulated by the system over a period of time. Such historical operating data may include system calibration records, performance test data under different environmental conditions, performance drift trends after long-term operation, or operating parameter records under specific fault modes. In this embodiment, historical operating data can be obtained by querying the operation log of the laser scanning system. The focus depth adjustment amount refers to the amount ultimately used to adjust the focus depth of the laser scanning system, which is obtained after further consideration of the real-time status of the system and the correction of historical performance data on the basis of the preliminary focus depth adjustment amount. This embodiment can adopt a correction model based on real-time parameters and historical data, an adaptive algorithm, a machine learning model, or first query a pre-calibrated current operating parameter and historical operating data-depth adjustment coefficient lookup table to obtain the focus depth adjustment coefficient, and then calculate the focus depth amount based on the preliminary focus depth adjustment amount and the focus depth adjustment coefficient to achieve adjustment of the preliminary focus depth adjustment amount according to the real-time operating parameters and historical operating data.

[0033] This solution not only determines the initial focus depth adjustment based on the actual Z-axis height of the fiducial marker, but also acquires the real-time operating parameters and historical operating data of the laser scanning system. Real-time operating parameters reflect the current operating environment and status of the laser scanning system, and the accuracy and stability of the laser scanning system are closely related to its operating environment and status. For example, temperature changes can cause subtle changes in the refractive index of optical components or mechanical structure dimensions, and vibrations can affect the stability of the optical path. Historical operating data provides long-term performance trends of the laser scanning system or its performance patterns under specific conditions. This embodiment utilizes these real-time parameters and historical data to correct the initial focus depth adjustment amount determined only based on the Z-axis height to obtain a more accurate focus depth adjustment amount. This means that the final focus adjustment not only compensates for the height fluctuations of the PCB board surface, but also takes into account the performance drift of the laser scanning system itself due to environmental changes or long-term use. Therefore, this embodiment can adjust the focus depth of the laser scanning system according to the corrected focus depth adjustment amount so that the laser spot can be more accurately focused on the surface of the reference mark point, thereby compensating for the impact of the unevenness of the PCB board surface and the changes in the system's own state on the focus accuracy, and enabling the laser scanning system to obtain a clear and stable laser spot at different heights and different system states. That is, this embodiment can significantly improve the robustness and accuracy of the focus adjustment, thereby further improving the accuracy and reliability of the subsequent acquisition of the original two-dimensional coordinate information and the two-dimensional coordinate correction, and further improving the drilling positioning accuracy.

[0034] In some preferred embodiments, the preset optical geometric parameters include the laser beam incident angle, the lens focal length, the lens distortion coefficient, the positions of the various optical elements, and the position of the image sensor. The laser beam incident angle of this embodiment can reflect the offset of the projection position of the laser point on planes at different heights relative to the reference plane. The lens focal length of this embodiment affects the imaging ratio and is the basis for the conversion between physical coordinates and image coordinates. The lens distortion coefficient of this embodiment is used to correct the inherent nonlinear distortion of the lens to ensure a one-to-one correspondence between image points and physical points. The positions of the various optical elements (such as reflectors, beam splitters, etc.) and the position of the image sensor of this embodiment can reflect the optical path and imaging plane. These positions are necessary information for establishing a complete optical model and performing coordinate conversion.

[0035] In some preferred embodiments, step S3 includes: S31, obtaining real-time operating parameters and historical operating data of the laser scanning system; S32, correcting preset optical geometric parameters of the laser scanning system according to the real-time operating parameters and historical operating data to obtain corrected optical geometric parameters; S33. For each reference mark point, use the laser scanning system to obtain the original two-dimensional coordinate information of the reference mark point, and then correct the original two-dimensional coordinate information according to the actual Z-axis height information and the corrected optical geometric parameters to obtain the corrected two-dimensional coordinate information.

[0036] Corrected optical geometric parameters refer to parameter values ​​obtained by adjusting preset optical geometric parameters based on real-time operating parameters and historical operating data. This embodiment can use mathematical model calculation or table lookup to correct the preset optical geometric parameters of the laser scanning system based on the real-time operating parameters and historical operating data. This embodiment can improve the accuracy of the correction of the original two-dimensional coordinate information by dynamically correcting the optical geometric parameters of the laser scanning system. Specifically, step S31 obtains the real-time operating parameters and historical operating data of the laser scanning system. These data reflect the current operating status of the system and possible changes over time, providing the necessary data foundation for subsequent optical geometric parameter correction. Step S32 corrects the preset optical geometric parameters of the laser scanning system based on the obtained real-time operating parameters and historical operating data to obtain corrected optical geometric parameters. This step recognizes that optical geometric parameters are not fixed but are affected by the system's operating status. Therefore, this embodiment can dynamically adjust the preset parameters using real-time and historical data so that the corrected optical geometric parameters more accurately reflect the actual optical characteristics of the system in its current state, thereby improving the accuracy of the optical geometric parameters. In step S33, the laser scanning system is used to obtain the original two-dimensional coordinate information for each fiducial marker. This information is then corrected by combining the actual Z-axis height information and the corrected optical geometric parameters to obtain corrected two-dimensional coordinate information. Compared to using fixed preset parameters, using corrected optical geometric parameters that are more realistic for the original two-dimensional coordinate information can more effectively eliminate measurement errors introduced by variations in optical system parameters. Therefore, this embodiment can make the corrected two-dimensional coordinate information more accurate, thereby improving the final drilling positioning accuracy.

[0037] In one embodiment, step S31 can specifically deploy temperature and vibration sensors to collect real-time temperature data near the laser scanning head or key optical components, as well as the vibration frequency and amplitude of the scanning system. Simultaneously, the system queries a historical database to obtain records of minor deviations in system calibration parameters under different temperature and vibration conditions over a period of time. Step S32 can utilize a polynomial regression model or lookup table trained based on historical data to obtain corrections to preset optical geometric parameters (e.g., lens focal length, distortion coefficient, etc.) based on the real-time collected temperature and vibration data and the records of minor deviations in system calibration parameters under different temperature and vibration conditions over a period of time. These corrections are then superimposed on the preset optical geometric parameters to obtain the corrected optical geometric parameters. Step S33 utilizes a standard coordinate correction algorithm (e.g., a coordinate transformation formula based on perspective projection and a distortion model) to calculate the corrected two-dimensional coordinate information based on the original two-dimensional coordinate information, the actual Z-axis height information, and the corrected optical geometric parameters.

[0038] In some preferred embodiments, the real-time operating parameters include the real-time temperature, real-time vibration frequency, and real-time vibration amplitude of the laser scanning system. The real-time temperature reflects the impact of the environment or the device's own heat on the optical elements and mechanical structure. These impacts may cause changes in optical parameters or relative positions. In this embodiment, the real-time temperature can be obtained using a temperature sensor provided on the laser scanning system. The real-time vibration frequency and real-time vibration amplitude reflect the vibration state of the laser scanning system during operation or when subject to external interference. Vibration can cause instability in the optical path or image acquisition. In this embodiment, the real-time vibration frequency and real-time vibration amplitude can be obtained using an accelerometer or vibration sensor provided on the laser scanning system.

[0039] In some preferred embodiments, step S4 includes: S41, calculating the translation amount, rotation amount, and stretching or shrinkage parameters of the PCB board according to all corrected two-dimensional coordinate information and the corresponding preset reference mark point positions; S42: Correct the preset drilling target point position according to the translation amount, rotation amount, and stretching or shrinking parameters to obtain a final drilling position of the drilling target point.

[0040] This solution details how to use the corrected two-dimensional coordinate information of the fiducial markers to correct the preset drilling target point position. Its core is to achieve a more comprehensive and accurate correction of the drilling target point position by calculating and applying the PCB material's translation, rotation, and stretch or shrinkage parameters, thereby improving the accuracy of the final drilling position. Specifically, the basis for correcting the drilling target point position is to calculate the PCB material's translation, rotation, and stretch or shrinkage parameters based on all corrected two-dimensional coordinate information and the corresponding preset fiducial marker positions. The preset fiducial marker positions are the ideal positions of the fiducial markers determined during PCB design. This embodiment can calculate the overall deformation of the PCB material in the XY plane relative to the ideal state based on the deviation between the corrected actual fiducial point positions and the ideal preset positions. This deformation is decomposed into three basic transformation types: translation, rotation, and stretch or shrinkage parameters. Since translation and rotation can reflect the rigid body displacement of the PCB material, and stretch or shrinkage parameters can reflect the non-rigid body deformation of the PCB material, this embodiment can more accurately obtain the actual deformation of the PCB material by calculating the PCB material's translation, rotation, and stretch or shrinkage parameters. After calculating the translation, rotation, and stretch or shrink parameters that reflect the overall deformation of the PCB board, the subsequent steps correct the preset drilling target point positions based on these parameters to obtain the final drilling position of the drilling target points. This means that each preset drilling target point will be mapped from its ideal position to its corresponding position after the actual deformation of the board based on the corresponding translation, rotation, and stretch / shrink transformations calculated previously, based on its relative position on the board. This embodiment can more accurately determine the final drilling position of each drilling target point on the actual PCB board through this correction based on the overall deformation parameters, effectively compensating for the positioning errors caused by various deformations of the board, thereby effectively improving drilling accuracy. In addition, because the reference point coordinates used to calculate the deformation parameters are corrected by the Z-axis height and optical combination parameters, this embodiment can make the calculated translation, rotation, and stretch or shrink parameters more accurate, thereby further improving the accuracy of the final drilling position.

[0041] From the above, it can be seen that the PCB drilling positioning method provided by the present application first obtains the actual Z-axis height information of each reference mark point, and uses the actual Z-axis height information to dynamically adjust the focus depth of the laser scanning system, and then uses the laser scanning system after adjusting the focus depth to collect the original two-dimensional coordinate information, and corrects the original two-dimensional coordinate information according to the actual Z-axis height information and optical geometric parameters to effectively solve the defocus and projection error problems caused by the unevenness of the PCB board. Therefore, the present application can effectively solve the problems of laser spot size change, reflected signal intensity and clarity damage caused by defocusing of the reference mark point, and avoid systematic deviations in the actual position calculation of the reference mark point and the deviation between the drilling position corrected based on the actual position and preset position of the reference mark point and the target drilling position, thereby effectively improving the accuracy of the image processing algorithm, product yield and electrical performance.

[0042] Second, as Figure 2 As shown, the present application also provides a PCB drilling positioning system, which includes: The structured light pattern image acquisition module 1 is used to acquire structured light pattern images corresponding to different reference mark points, where the structured light pattern images include a preset structured light pattern whose projection area covers the reference mark points; Focus depth adjustment module 2, for obtaining actual Z-axis height information of each reference mark point according to the structured light pattern image, and then adjusting the focus depth of the laser scanning system according to the actual Z-axis height information; The two-dimensional coordinate correction module 3 is used to obtain the original two-dimensional coordinate information of each reference mark point using the laser scanning system, and then correct the original two-dimensional coordinate information according to the actual Z-axis height information and the preset optical geometric parameters of the laser scanning system to obtain the corrected two-dimensional coordinate information; The drilling position determination module 4 is used to correct the preset drilling target point position according to all corrected two-dimensional coordinate information to obtain the final drilling position of the drilling target point.

[0043] A PCB drilling positioning system provided in this application includes a structured light pattern image acquisition module 1, a focus depth adjustment module 2, a two-dimensional coordinate correction module 3, and a drilling position determination module 4. The PCB drilling positioning system provided in this embodiment is used to perform the steps of the PCB drilling positioning method provided in the first aspect above. The principle of the PCB drilling positioning system provided in this embodiment is the same as the principle of the PCB drilling positioning method provided in the first aspect above, and will not be discussed in detail here.

[0044] As can be seen from the above, the PCB drilling positioning method and system provided by the present application first obtains the actual Z-axis height information of each reference mark point, and uses the actual Z-axis height information to dynamically adjust the focus depth of the laser scanning system, and then uses the laser scanning system after adjusting the focus depth to collect the original two-dimensional coordinate information, and corrects the original two-dimensional coordinate information according to the actual Z-axis height information and optical geometric parameters to effectively solve the defocus and projection error problems caused by the unevenness of the PCB board. Therefore, the present application can effectively solve the problems of laser spot size change, reflected signal intensity and clarity damage caused by defocus of the reference mark point, and avoid systematic deviations in the actual position calculation of the reference mark point and deviations between the drilling position obtained based on the actual position and preset position of the reference mark point and the target drilling position, thereby effectively improving the accuracy of the image processing algorithm, product yield and electrical performance.

[0045] In the embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the above-mentioned units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another robot, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interface, the indirect coupling or communication connection of the device or unit can be electrical, mechanical or other forms.

[0046] In addition, the functional modules in each embodiment of the present application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0047] In this document, relational terms such as first and second, etc. are used merely to distinguish one entity or operation from another entity or operation, but do not necessarily require or imply any actual relationship or order between these entities or operations.

[0048] The above description is merely an embodiment of the present application and is not intended to limit the scope of protection of the present application. For those skilled in the art, various modifications and variations of the present application are possible. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A PCB drilling positioning method, characterized in that: The PCB drilling positioning method comprises the following steps: S1. Acquire a structured light pattern image corresponding to different reference mark points, wherein the structured light pattern image includes a preset structured light pattern whose projection area covers the reference mark points; S2. For each of the reference mark points, obtain actual Z-axis height information according to the structured light pattern image, and then adjust the focus depth of the laser scanning system according to the actual Z-axis height information; S3. For each of the reference marking points, obtain original two-dimensional coordinate information of the reference marking point using a laser scanning system, and then correct the original two-dimensional coordinate information according to the actual Z-axis height information and preset optical geometric parameters of the laser scanning system to obtain corrected two-dimensional coordinate information; S4. Correct the preset drilling target point position according to all corrected two-dimensional coordinate information to obtain the final drilling position of the drilling target point.

2. The PCB drilling positioning method according to claim 1, characterized in that: The preset structured light pattern is a stripe pattern, a dot pattern or a coded pattern.

3. The PCB drilling positioning method according to claim 1, characterized in that: Step S2 includes: S21. For each of the reference mark points, perform a PCB board surface feature analysis on the structured light pattern image, and then process the structured light pattern image according to the analysis result to reduce the influence of the PCB board surface feature on the recognition of the preset structured light pattern; S22 . For each of the reference marking points, obtain actual Z-axis height information according to the structured light pattern image, and then adjust the focus depth of the laser scanning system according to the actual Z-axis height information.

4. The PCB drilling positioning method according to claim 3, characterized in that: Step S22 includes: S221. For each of the reference marking points, locally analyze the structured light pattern image to obtain Z-axis height data of multiple analysis areas, and then use the Z-axis height data corresponding to the analysis area where the reference marking point is located as actual Z-axis height information; S222. For each of the reference mark points, adjust the focus depth of the laser scanning system according to the corresponding actual Z-axis height information.

5. The PCB drilling positioning method according to claim 4, characterized in that: Step S222 includes: A1. For each of the reference mark points, determine a preliminary focus depth adjustment amount based on the corresponding actual Z-axis height information; A2. Obtain the real-time operating parameters and historical operating data of the laser scanning system; A3. For each of the reference mark points, the initial focus depth adjustment amount is adjusted according to the real-time operating parameters and historical operating data to obtain a focus depth adjustment amount, and then the focus depth of the laser scanning system is adjusted according to the focus depth adjustment amount.

6. The PCB drilling positioning method according to claim 1, characterized in that: The preset optical geometric parameters include the laser beam incident angle, the lens focal length, the lens distortion coefficient, the position of each optical element and the position of the image sensor.

7. The PCB drilling positioning method according to claim 1, characterized in that: Step S3 includes: S31, obtaining real-time operating parameters and historical operating data of the laser scanning system; S32, correcting preset optical geometric parameters of the laser scanning system according to the real-time operating parameters and the historical operating data to obtain corrected optical geometric parameters; S33. For each of the reference mark points, use a laser scanning system to obtain the original two-dimensional coordinate information of the reference mark point, and then correct the original two-dimensional coordinate information according to the actual Z-axis height information and the corrected optical geometric parameters to obtain corrected two-dimensional coordinate information.

8. The PCB drilling positioning method according to claim 5 or claim 7, characterized in that: The real-time operating parameters include the real-time temperature, real-time vibration frequency and real-time vibration amplitude of the laser scanning system.

9. The PCB drilling positioning method according to claim 1, characterized in that: Step S4 includes: S41, calculating the translation amount, rotation amount, and stretching or shrinkage parameters of the PCB board according to all the corrected two-dimensional coordinate information and the corresponding preset reference mark point positions; S42: Correct the preset drilling target point position according to the translation amount, the rotation amount, and the stretching or shrinking parameter to obtain a final drilling position of the drilling target point.

10. A PCB drilling positioning system, characterized in that: The PCB drilling positioning system includes: a structured light pattern image acquisition module, configured to acquire structured light pattern images corresponding to different reference mark points, wherein the structured light pattern images include preset structured light patterns whose projection areas cover the reference mark points; a focus depth adjustment module, configured to obtain actual Z-axis height information for each of the reference marking points according to the structured light pattern image, and then adjust the focus depth of the laser scanning system according to the actual Z-axis height information; a two-dimensional coordinate correction module, configured to obtain, for each of the reference marking points, original two-dimensional coordinate information of the reference marking point using a laser scanning system, and then correct the original two-dimensional coordinate information based on the actual Z-axis height information and preset optical geometric parameters of the laser scanning system to obtain corrected two-dimensional coordinate information; The drilling position determination module is used to correct the preset drilling target point position according to all the corrected two-dimensional coordinate information to obtain the final drilling position of the drilling target point.

Images