Method for acquiring back drilling position, back drilling method and device, electronic equipment and storage medium

Abstract

According to the method for obtaining the back drilling position, the back drilling method and device, the electronic equipment and the storage medium provided by the invention, the center coordinate information of the target through hole in the circuit board in the first circular hole in the first surface and the center coordinate information of the target through hole in the second circular hole in the second surface are obtained; the actual thickness of the circuit board and the actual depth of the back drilling stop layer of the circuit board are obtained; based on the center coordinate information of the first circular hole, the center coordinate information of the second circular hole, the actual depth and the actual thickness, calculating the center coordinate information of a third circular hole of the target through hole in a back drilling stop layer in the circuit board, so as to determine the center coordinate information of the third circular hole as a back drilling position when the target through hole is subjected to back drilling, the center coordinate information of the third round hole in the back drilling stop layer is used as the back drilling position, so that the back drilling position is concentric with the third round hole, and the symmetry of the Stub can be improved.

Description

Technical Field

[0001] This application belongs to the field of circuit board processing technology, and in particular relates to a method, back-drilling method, apparatus, electronic device and storage medium for obtaining back-drilling position. Background Technology

[0002] As digital products become increasingly high-speed and high-density, the back-drilling process for high-density multilayer printed circuit boards (PCBs) faces increasingly stringent requirements for signal integrity. Traditional back-drilling relies on the coordinates of holes on the PCB surface for positioning. For example, patent application number 202010388581.6 discloses a method of: first, drilling through holes at predetermined positions on the PCB board to form first and second holes on two surfaces respectively; then, obtaining the center coordinates of the first hole, detecting the board thickness, and calculating the theoretical center coordinates of the second hole; next, detecting the second hole and obtaining its first coordinate data, and simultaneously obtaining its first coordinate data from the center coordinates of the first hole, thereby calculating the hole position deviation value of the second hole; further calculating the actual center coordinates of the second hole; finally, using these as the initial coordinates, a second drilling is performed with a drill bit of a larger diameter. It can be seen that this patent uses surface hole coordinates for back-drilling. Due to the increased length-to-diameter ratio of the drill bit, when drilling a through hole, the drill bit tilts due to the yaw of the drill bit and the lateral force of the fiberglass cloth entering the hole, causing the through hole to tilt.

[0003] Figure 1 This is a flowchart illustrating a circuit board manufacturing method provided in related technologies, such as... Figure 1 As shown, firstly, through hole 100 is machined. The through hole will drill through the back drill stop layer 200. Through hole 100 is tilted. At this time, the inner layer residual copper will present an asymmetrical residual stub with one side longer than the other. The residual stub 400 on the left is longer and the residual stub 500 on the right is shorter. The asymmetrical stub will cause signal distortion and electromagnetic interference problems. Summary of the Invention

[0004] In view of this, embodiments of this application provide a method, method, apparatus, electronic device and storage medium for obtaining back-drilling position, which determines the center coordinate information of the circular hole in the back-drilling stop layer as the back-drilling position when back-drilling the target through hole, thereby improving the symmetry of the stub.

[0005] In a first aspect, embodiments of this application provide a method for obtaining the back-drill position, for a circuit board having multiple through holes, including: Obtain the center coordinate information of the first circular hole on the first surface and the center coordinate information of the second circular hole on the second surface of the target through hole in the circuit board, as well as obtain the actual thickness of the circuit board and the actual depth of the back drill stop layer of the circuit board; Based on the center coordinate information of the first circular hole, the center coordinate information of the second circular hole, the actual depth, and the actual thickness, the center coordinate information of the third circular hole on the back-drilling stop layer of the target through hole is calculated, so as to determine the center coordinate information of the third circular hole as the back-drilling position when back-drilling the target through hole. The target through hole is one or more of the through holes, and the back-drilling stop layer is the layer that prohibits drilling through the target through hole when back-drilling.

[0006] In some embodiments, calculating the center coordinate information of the third circular hole on the back-drill stop layer of the target through-hole on the circuit board based on the center coordinate information of the first circular hole, the center coordinate information of the second circular hole, the actual depth, and the actual thickness includes: The calculated ratio is obtained by dividing the actual depth by the actual thickness. The offset is obtained by subtracting the center coordinates of the first circular hole from the center coordinates of the second circular hole. Multiply the offset by the calculated ratio to obtain the corrected offset; The center coordinates of the third hole are obtained by adding the correction offset to the center coordinates of the first hole.

[0007] In some embodiments, obtaining the actual thickness of the circuit board and the actual depth of the back-drill stop layer of the circuit board includes: Obtain the theoretical depth of the back-drill stop layer, the theoretical thickness of the circuit board, and the actual thickness of the circuit board; Divide the actual thickness by the theoretical thickness to obtain the thickness ratio; Multiplying the theoretical depth by the thickness ratio yields the actual thickness of the back-drilling stop layer.

[0008] In some embodiments, the target through-hole is formed as a circular hole on the first surface and the second surface of the circuit board, respectively. Obtaining the center coordinate information of the first circular hole on the first surface and the center coordinate information of the second circular hole on the second surface of the target through-hole in the circuit board includes: Acquire first image information of the first surface and first image information of the second surface of the circuit board, and determine the center coordinate information of the circular hole on the first surface and the center coordinate information of the circular hole on the second surface based on the first image information and the second image information; Based on the center coordinate information of the circular holes on the first surface and the center coordinate information of the circular holes on the second surface, a point set alignment algorithm is used to obtain the circular holes on the first surface and the circular holes on the second surface corresponding to each target through hole, so as to obtain the center coordinate information of the first circular hole on the first surface and the center coordinate information of the second circular hole on the second surface of the target through hole.

[0009] In some embodiments, determining the center coordinates of the circular holes on the first surface and the second surface based on the first image information and the second image information includes: The first image information is binarized to obtain a first binarized image. The edge information of the circular hole on the first surface is determined based on the first binarized image, and the center coordinate information of the circular hole on the first surface is determined based on the edge information of the circular hole on the first surface. The second image information is binarized to obtain a second binarized image. The edge information of the circular hole on the second surface is determined based on the second binarized image, and the center coordinate information of the circular hole on the second surface is determined based on the edge information of the circular hole on the second surface.

[0010] In some embodiments, the method further includes: The first number of circular holes on the first surface is identified based on the first image information; The second number of circular holes on the second surface is identified based on the second image information; The circuit board is tested based on the first quantity and the second quantity.

[0011] Secondly, embodiments of this application provide an apparatus for obtaining the position of a back drill bit, comprising: The acquisition module is used to acquire the center coordinate information of the first circular hole on the first surface and the center coordinate information of the second circular hole on the second surface of the target through hole in the circuit board, as well as to acquire the actual thickness of the circuit board and the actual depth of the back drill stop layer of the circuit board. The determination module is used to calculate the center coordinate information of the third circular hole on the back-drilling stop layer of the target through hole on the circuit board based on the center coordinate information of the first circular hole, the center coordinate information of the second circular hole, the actual depth, and the actual thickness, so as to determine the center coordinate information of the third circular hole as the back-drilling position when back-drilling the target through hole, wherein the back-drilling stop layer is a layer that prohibits drilling through the target through hole.

[0012] Thirdly, embodiments of this application provide a back-drilling method, including: The back drill position obtained by the method for obtaining the back drill position described in the first aspect; The circuit board is back-drilled based on the back-drilling position.

[0013] Fourthly, embodiments of this application provide an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the method described in any of the above-mentioned embodiments.

[0014] Fifthly, embodiments of this application provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the method described in any of the preceding claims.

[0015] Sixthly, embodiments of this application provide a computer program product that, when run on a terminal device, causes the electronic device to execute any of the methods described above.

[0016] The beneficial effects of the embodiments in this application compared with the prior art are: This application provides a method for obtaining the back-drilling position. This method involves acquiring the center coordinates of a first circular hole on the first surface and a second circular hole on the second surface of a target through-hole on a circuit board, as well as the actual thickness of the circuit board and the actual depth of the back-drilling stop layer. Based on the center coordinates of the first and second circular holes, the actual depth, and the actual thickness, the method calculates the center coordinates of a third circular hole on the back-drilling stop layer of the target through-hole. The center coordinates of the third circular hole are then used as the back-drilling position for back-drilling the target through-hole. By using the center coordinates of the third circular hole on the back-drilling stop layer as the back-drilling position, the back-drilling position is concentric with the third circular hole, thereby improving the symmetry of the stub and solving the problem of uneven stub length caused by drill bit tilting in existing PCB back-drilling processes. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart illustrating a circuit board manufacturing method provided in related technologies; Figure 2 A schematic diagram illustrating the implementation process of a method for obtaining the back drill position provided for the implementation of this application; Figure 3 This is a schematic diagram of the process for processing a circuit board using the back drill position determined by the method provided in the embodiments of this application; Figure 4 A schematic diagram of a device for obtaining the position of a back drill provided in an embodiment of this application; Figure 5 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0019] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0020] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0021] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0022] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrases "if determined" or "if detected" may be interpreted, depending on the context, as "once determined," "in response to determination," "once detected," or "in response to detection."

[0023] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0024] References to "one embodiment" or "some embodiments" in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized.

[0025] The applicant carefully studied the existing back-drilling method and found that the reason for the asymmetric stub is that the drill bit 300 back-drills at the position of the surface hole. At this time, the back-drilled hole and the through hole 100 will have a certain angle, which will cause tilting during drilling. Therefore, the applicant tried to determine the center coordinate information of the circular hole of the back-drilling stop layer as the back-drilling position when back-drilling the target through hole, thereby improving the symmetry of the stub.

[0026] This application provides a method for obtaining the back drill position that can be applied to electronic devices, including mobile phones, tablets, wearable devices, augmented reality (AR) / virtual reality (VR) devices, laptops, ultra-mobile personal computers (UMPCs), netbooks, personal digital assistants (PDAs), etc. The electronic device can serve as a controller for a machining system. This application does not impose any limitations on the specific type of electronic device. Figure 2 A schematic diagram illustrating the implementation process of a method for obtaining the back drill position provided for the purposes of this application is shown below. Figure 2 As shown, it includes: Step S101: Obtain the center coordinate information of the first circular hole on the first surface and the center coordinate information of the second circular hole on the second surface of the target through hole in the circuit board, as well as obtain the actual thickness of the circuit board and the actual depth of the back drill stop layer of the circuit board.

[0027] In this embodiment, the target via is a metallized via in a circuit board that requires back-drilling to achieve interlayer electrical connections. The circuit board typically has multiple vias, and the target via can be one or more of these vias. The circuit board can be a PCB (Printed Circuit Board), which is typically made of multiple layers of materials with different functions bonded together using a thermoforming process. In this embodiment, the PCB includes at least a first surface layer, a second surface layer, and a back-drill stop layer located between the first and second surface layers. A dielectric layer is provided between the first surface layer and the back-drill stop layer, and the second surface layer and the back-drill stop layer also have dielectric layers. The first and second surface layers can be copper foil layers. The back-drill stop layer is a conductive layer in the PCB used for signal transmission, containing critical signal traces. When back-drilling this stop layer, penetration of the signal layer must be strictly avoided, otherwise signal integrity will be compromised or a short circuit will occur. Here, the first surface can be the surface of the first surface layer away from the dielectric layer, and the second surface can be the surface of the second surface layer away from the dielectric layer. The first surface layer can be the top layer, and the second surface layer can be the bottom layer. In some embodiments, the first surface layer can be the bottom layer, and the second surface layer can be the top layer. When the first surface layer is the top layer, the first surface can be the top surface; when the first surface layer is the bottom layer, the first surface is the bottom surface. When the first surface is the top surface, the second surface is the bottom surface; and when the first surface is the bottom surface, the second surface is the top surface. The first circular hole and the second circular hole are circular openings formed by the target through-hole on the first and second surfaces, and their center coordinates reflect the surface hole position. The first circular hole on the first surface can be an inlet hole, and the second circular hole on the second surface can be an outlet hole. Of course, the first circular hole on the first surface can be an outlet hole, and the second circular hole on the second surface can be an inlet hole.

[0028] In this embodiment, a high-precision charge-coupled device (CCD) vision system or a laser displacement sensor can be used to image the target through-holes on the first and second surfaces, respectively. The edges of the circular holes are extracted using an edge detection algorithm, and the center coordinates of the holes are fitted to obtain the center coordinate information (X1, Y1) of the first circular hole and the center coordinate information (X2, Y2) of the second circular hole.

[0029] In this embodiment, the actual depth of the back-drill stop layer is the vertical distance of the back-drill stop layer relative to the first surface. The actual depth of the back-drill stop layer can be calculated from its theoretical depth, and the actual thickness of the circuit board can be obtained by measurement.

[0030] Step S102: Based on the center coordinate information of the first circular hole, the center coordinate information of the second circular hole, the actual depth, and the actual thickness, calculate the center coordinate information of the third circular hole on the back drilling stop layer of the target through hole in the circuit board, so as to determine the center coordinate information of the third circular hole as the back drilling position when back drilling the target through hole.

[0031] In this embodiment, the back-drill stop layer is an intermediate layer in the PCB that carries high-speed signals. Back-drilling is necessary to eliminate stubs and ensure signal integrity. The third circular hole is the actual hole position projection of the target via on the back-drill stop layer, and its center coordinates are the precise positioning target for back-drilling. The drill bit is inserted from one end but not to the other, only removing a portion of the copper, leaving a hollow channel. The purpose is to cut off the remaining copper stub and avoid signal interference.

[0032] In this embodiment, the actual depth of the back-drill stop layer and the actual thickness of the circuit board can be obtained. Based on the center coordinates of the first circular hole, the center coordinates of the second circular hole, the actual depth, and the actual thickness, the center coordinates of the third circular hole are calculated. The center coordinates of the third circular hole can be represented as (X3, Y3). After obtaining the center coordinates of the third circular hole, the calculated center coordinates (X3, Y3) are input to the CNC drilling machine control system to drive the drill bit to accurately position itself at the back-drill stop layer hole position and perform back-drilling.

[0033] The method provided in this application embodiment obtains the center coordinate information of the first circular hole on the first surface and the center coordinate information of the second circular hole on the second surface of the target through hole in the circuit board, as well as the actual thickness of the circuit board and the actual depth of the back drill stop layer of the circuit board; based on the center coordinate information of the first circular hole, the center coordinate information of the second circular hole, the actual depth and the actual thickness, the center coordinate information of the third circular hole on the back drill stop layer of the target through hole is calculated, so as to determine the center coordinate information of the third circular hole as the back drill position when back drilling the target through hole. Since the center coordinate information of the third circular hole on the back drill stop layer is used as the back drill position, the back drill position is concentric with the third circular hole, thereby improving the symmetry of the stub and solving the problem of the stub being longer on one side and shorter on the other side due to the drill bit tilt in the PCB back drilling process of the prior art.

[0034] Figure 3 This is a schematic diagram illustrating the process of fabricating a circuit board using the back-drilling position determined by the method provided in the embodiments of this application. Figure 3As shown, a through hole 100 is first drilled on the circuit board. The through hole penetrates the back drill stop layer 200. It can be seen that the drilled through hole is tilted. When the drill bit 300 is used for vertical back drilling with the center coordinate information of the third circular hole, the drill bit 300 will not penetrate the back drill stop layer 200. The position of the back drill is not offset from the center coordinate of the third circular hole. After the back drill, the lengths of the left residual pile 400 and the right residual pile 500 are basically the same, that is, the symmetry of the stub is good. Even if the drilled through hole is tilted, the back drill hole can still be concentric with the drilled hole in the back drill stop layer, thus ensuring the symmetry of the stub.

[0035] In some embodiments, step S102 can be implemented by the following steps: Step S1021: Divide the actual depth by the actual thickness to obtain the calculated ratio.

[0036] In this embodiment of the application, the calculated ratio can be obtained by dividing the actual depth by the actual thickness.

[0037] Step S1022: Subtract the center coordinates of the first circular hole from the center coordinates of the second circular hole to obtain the offset.

[0038] In this embodiment of the application, the offset can be obtained by subtracting the center coordinates (X1, Y1) of the first circular hole from the center coordinates (X2, Y2) of the second circular hole. X, Y).

[0039] Step S1023: Multiply the offset by the calculated ratio to obtain the corrected offset.

[0040] In this embodiment of the application, the corrected offset = offset ( X, Y)×(actual depth÷actual thickness).

[0041] Step S1024: Add the correction offset to the center coordinate information of the first circular hole to obtain the center coordinate information of the third circular hole.

[0042] In this embodiment, the center coordinate information (X3, Y3) of the third circular hole = the center coordinate information (X1, Y1) of the first circular hole + the correction offset.

[0043] The method provided in this application embodiment dynamically adjusts the coordinates based on the deviation between the actual circuit board thickness and the theoretical value in actual production, ensuring that the back drill position is accurately aligned with the actual position of the back drill stop layer, thereby eliminating stub deviation. By correcting the actual thickness and proportion, it avoids depth calculation errors caused by changes in board thickness.

[0044] In some embodiments, step S101 can be implemented by the following steps: Step S1011: Obtain the theoretical depth of the back drill stop layer, the theoretical thickness of the circuit board, and the actual thickness of the circuit board.

[0045] In this embodiment, the theoretical depth of the back-drill stop layer is the vertical distance from the back-drill stop layer to the first surface of the circuit board, preset during the design phase. This is typically calculated based on PCB stack-up design parameters, which may include, for example, copper foil thickness and dielectric layer thickness. The theoretical depth of the back-drill stop layer is obtained by adding the copper foil thickness and dielectric layer thickness. The theoretical thickness of the circuit board is the total thickness preset during the design phase, derived by summing the thicknesses of each layer. The actual thickness of the circuit board is the actual total thickness obtained through physical measurement. It may deviate from the theoretical value due to lamination process tolerances, material deformation, or environmental factors. The actual thickness of the circuit board can be measured using a laser thickness gauge or a micrometer.

[0046] In this embodiment, the theoretical depth of the back-drill stop layer and the theoretical thickness of the circuit board can be read from the PCB design file. A high-precision laser thickness gauge or micrometer is used to measure at multiple points along the edge of the circuit board or around the holes, and the average value is taken as the actual thickness of the circuit board.

[0047] Step S1012: Divide the actual thickness by the theoretical thickness to obtain the thickness ratio.

[0048] In this embodiment, the thickness ratio is the ratio of the actual thickness to the theoretical thickness, used to quantify the thickness change caused by the pressing process.

[0049] Step S1013: Multiply the theoretical depth by the thickness ratio to obtain the actual depth of the back-drilling stop layer.

[0050] In this embodiment, the actual depth of the back drill stop layer is the true vertical distance from the back drill stop layer to the first surface after considering the pressing tolerance, which is calculated by multiplying the theoretical depth by the thickness ratio.

[0051] The method provided in this application embodiment can obtain the accurate actual depth of the back-drilling stop layer.

[0052] In some embodiments, step S101 further includes: Step S1014: Obtain first image information of the first surface and first image information of the second surface of the circuit board.

[0053] In this embodiment, the first image information and the second image information can be two-dimensional images of the circuit board surface captured by a high-resolution industrial camera, and the two-dimensional images include the edge contours of through holes. The through holes are formed by drilling, and the number of through holes is typically set according to the actual product requirements.

[0054] In this embodiment, the circuit board can be placed on a stage and fixed by vacuum adsorption. A dual industrial camera system is used to align with the first surface and the second surface respectively, thereby acquiring first image information and second image information. The dual industrial camera system may include: a first camera and a second camera. The first camera acquires the image of the first surface, and the second camera simultaneously acquires the image of the second surface.

[0055] In some embodiments, a single industrial camera system can also be used to acquire the first image information and the second image information. When using a single industrial camera system, the camera can first acquire the first image information of the first surface, then flip the circuit board, and then acquire the second image information of the second surface.

[0056] Step S1015: Determine the center coordinate information of the circular hole on the first surface and the center coordinate information of the circular hole on the second surface based on the first image information and the second image information.

[0057] In this embodiment of the application, the center of the circle can be extracted from the first image information and the second image information by an image processing algorithm, thereby obtaining the center coordinate information of the circular hole on the first surface and the center coordinate information of the circular hole on the second surface.

[0058] In some embodiments, step S1015 can be implemented by the following steps: Step S151: Binarize the first image information to obtain a first binarized image; determine the edge information of the circular hole on the first surface based on the first binarized image; and determine the center coordinate information of the circular hole on the first surface based on the edge information of the circular hole on the first surface.

[0059] In this embodiment, before binarizing the first image information, denoising and contrast enhancement processes can be performed on the first image information. Median filtering or Gaussian filtering can be used to eliminate image noise. Histogram equalization or adaptive thresholding can be used to improve the contrast between the circular hole and the background.

[0060] In this embodiment, the first image information can be globally thresholded or adaptively thresholded to convert the image into a black-and-white binary image, resulting in a first binary image. In the first binary image, the circular hole region is black, and the background is white. Then, an edge detection algorithm is used to extract the edge of the circular hole, obtaining its edge information. This edge information is a closed contour line, and the edge detection algorithm can be the Canny algorithm. After obtaining the closed contour line, the center coordinates of the circular hole on the first surface can be calculated.

[0061] In this embodiment, the center coordinates of the circular holes on the first surface can be obtained using the geometric center method, the centroid method, or least squares fitting. The geometric center method calculates the center of the smallest circumcircle of each closed contour line as the center coordinates. The centroid method calculates the centroid of all pixels within the contour to obtain the center coordinate information. Least squares fitting fits the contour points using a circle equation and then solves for the optimal center coordinates.

[0062] Step S152: Binarize the second image information to obtain a second binarized image; determine the edge information of the circular hole on the second surface based on the second binarized image; and determine the center coordinate information of the circular hole on the second surface based on the edge information of the circular hole on the second surface.

[0063] In this embodiment of the application, the center coordinate information of the circular hole on the second surface can be obtained by determining the center coordinate information of the circular hole on the first surface.

[0064] Step S1016: Based on the center coordinate information of the circular holes on the first surface and the center coordinate information of the circular holes on the second surface, a point set alignment algorithm is used to obtain the circular holes on the first surface and the circular holes on the second surface corresponding to each through hole, so as to obtain the center coordinate information of the first circular hole on the first surface and the center coordinate information of the second circular hole on the second surface of the target through hole.

[0065] In this embodiment, the point set alignment algorithm is a mathematical method that transforms the center coordinate information of the circular holes on the first surface and the center coordinate information of the circular holes on the second surface through rotation, translation, scaling, etc., to achieve optimal matching between the two sets of point sets. The point set alignment algorithm may include the ICP (Iterative Closest Point) algorithm, which achieves registration by iteratively minimizing the distance between point pairs.

[0066] In this embodiment, the center coordinate information set of the circular holes on the first surface can be denoted as P = {p1, p2, ..., pn}, and the center coordinate information set of the circular holes on the second surface can be denoted as Q = {q1, q2, ..., qn}; ensuring that the number of points in both sets is the same. For each point pi in P, find the nearest point qj in Q; calculate the optimal transformation matrix; apply the transformation matrix to update the position of P; repeat the steps until convergence, thereby outputting the matching result: {(p1', q1), (p2', q2), ..., (pn', qn)}, where pi' is a center coordinate information in P. The center coordinate information of the first circular hole corresponds to the center coordinate information of a second circular hole, and there is a one-to-one correspondence.

[0067] The method provided in this application embodiment can obtain the center coordinate information of the circular holes on the first surface and the center coordinate information of the circular holes on the second surface corresponding to each through hole through registration. Since the center coordinate information of the circular holes on the first surface and the center coordinate information of the circular holes on the second surface corresponding to each through hole are obtained, the center coordinate information of the first circular hole on the first surface and the center coordinate information of the second circular hole on the second surface of the target through hole can be obtained.

[0068] In some embodiments, after step S1014, the method further includes: Step S1017: Identify the first number of circular holes on the first surface based on the first image information.

[0069] In this embodiment of the application, the first quantity refers to the number of circular holes detected on the first surface of the circuit board by image recognition.

[0070] In this embodiment, median filtering or Gaussian filtering can be used to eliminate image noise in the first image information. Adaptive thresholding converts the image into a black-and-white binary image, with the circular hole area in black and the background in white. The circular holes are then identified using the black-and-white binary image, and the identified holes are counted to obtain a first quantity.

[0071] In this embodiment, circular holes can be identified using connected component analysis or Hough circle transform. Taking connected component analysis as an example, all connected regions in the black-and-white binary image are marked, and the area, perimeter, and circularity of each connected region are calculated. Regions that meet the criteria are then selected as circular holes. These criteria can be determined based on the size of the hole; if the deviation between the size of the connected region and the size of the hole is small, then that region can be identified as a circular hole.

[0072] Step S1018: Identify the second number of circular holes on the second surface based on the second image information.

[0073] In this embodiment, the second quantity refers to the number of circular holes detected on the second surface of the circuit board through image recognition. The processing method for the second quantity can be the same as that in step S1017.

[0074] Step S1019: Determine whether the first quantity and the second quantity are consistent.

[0075] In this embodiment, the first quantity and the second quantity can be used to determine whether they are consistent. By determining whether they are consistent, the problem of missing holes or holes that are not drilled through can be detected, thereby ensuring that the number of through holes on both sides of the circuit board is consistent.

[0076] In this embodiment of the application, if there is a discrepancy, the production interface can display "The number of circular holes on the first surface and the second surface are inconsistent" and mark the number of differences.

[0077] In this embodiment of the application, when the quantities are consistent, step S1016 is executed.

[0078] The method provided in this application, by judging a first quantity and a second quantity, can ensure that the number of circular holes on both sides of the circuit board is consistent, avoiding problems such as missed holes or holes not being drilled through. By automatically detecting whether the quantity is consistent, the detection efficiency and accuracy can be improved. Consistent quantity is a prerequisite for point set alignment. If the quantity is inconsistent, forced alignment will lead to incorrect matching, ultimately causing back-drilling position errors.

[0079] Based on the foregoing embodiments, this application further provides a method for obtaining the back drill position, including: A CCD camera is installed facing each other vertically, and a standard board is used to correct the installation eccentricity. After drilling and electroplating the circuit board, the hole positions on the top and bottom surfaces of the circuit board are scanned to calculate whether the number of holes on the top and bottom surfaces of the circuit board after drilling is consistent. Check for any missed holes or holes that are not drilled through, and ensure that the number of drilled holes on the top and bottom surfaces of the circuit board is consistent.

[0080] After scanning the holes for pixels, the edges of the holes are determined through binarization, and the center coordinates of the first and second circular holes are determined.

[0081] Since there is a one-to-one correspondence between the holes on the upper and lower surfaces, and a one-to-one correspondence between the first and second circular holes, the ICP algorithm can be used to find the one-to-one correspondence between the first and second circular holes, thereby obtaining the center coordinate information of the first and second circular holes.

[0082] After finding the center coordinates of the first and second circular holes, the center coordinates of the third circular hole at the back-drilling stop layer are calculated based on the center coordinates of the first and second circular holes. The center coordinates of the third circular hole can then be used to determine the coordinate position of the back-drilling hole.

[0083] The calculation formula is as follows: Center coordinates of the third hole (X3, Y3) = Center coordinates of the first hole (X1, Y1) + Correction offset, where the offset ( X, Y) = Center coordinates of the second hole (X2, Y2) - Center coordinates of the first hole (X1, Y1), Correction offset = Offset ( X, Y) × (actual depth ÷ actual thickness).

[0084] In this embodiment of the application, the actual depth = theoretical depth of the back-drilling stop layer × actual plate thickness ÷ theoretical plate thickness.

[0085] The method provided in this application embodiment generates a new drill strip using a modified coordinate system, which can correct an asymmetric back drill stub into a symmetric stub.

[0086] Based on the foregoing embodiments, this application provides a back-drilling method, the method comprising: The back drill position is obtained by a method for obtaining the back drill position, and the circuit board is back drilled based on the back drill position.

[0087] In this embodiment, back drilling is a special depth-controlled drilling technique used to remove unwanted portions within through holes in multilayer PCBs to improve signal integrity.

[0088] In this embodiment, the center coordinates of the third circular hole on the back-drilling stop layer of the target through-hole can be obtained as the back-drilling position. The obtained back-drilling position information is input into the back-drilling equipment to control the back-drilling equipment to perform drilling at the specified position.

[0089] The method provided in this application improves the symmetry of the stub by using the center coordinates of the third circular hole on the back-drilling stop layer as the back-drilling position.

[0090] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0091] According to the foregoing embodiments, this application provides a device for obtaining the back drill position. The various modules and units included in the device can be implemented by a processor in a computer device; of course, they can also be implemented by specific logic circuits. In the implementation process, the processor can be a central processing unit (CPU), a microprocessor (MPU), a digital signal processor (DSP), or a field programmable gate array (FPGA), etc.

[0092] This application provides an apparatus for obtaining the back drill position, used on a circuit board with multiple through holes. Figure 4 This is a schematic diagram of a device for obtaining the position of a back drill bit, provided in an embodiment of this application. Figure 4 As shown, the device 600 for obtaining the back drill position includes: The acquisition module 601 is used to acquire the center coordinate information of the first circular hole on the first surface and the center coordinate information of the second circular hole on the second surface of the target through hole in the circuit board, as well as to acquire the actual thickness of the circuit board and the actual depth of the back drill stop layer of the circuit board. The determining module 602 is used to calculate the center coordinate information of the third circular hole on the back-drilling stop layer of the target through hole on the circuit board based on the center coordinate information of the first circular hole, the center coordinate information of the second circular hole, the actual depth and the actual thickness, so as to determine the center coordinate information of the third circular hole as the back-drilling position when back-drilling the target through hole, wherein the target through hole is one or more of the through holes.

[0093] In some embodiments, the determining module includes: The first calculation unit is used to divide the actual depth by the actual thickness to obtain a calculated ratio. The second calculation unit is used to subtract the center coordinate information of the first circular hole from the center coordinate information of the second circular hole to obtain the offset. The third calculation unit is used to multiply the offset by the calculated ratio to obtain the corrected offset; The fourth calculation unit is used to add the correction offset to the center coordinate information of the first circular hole to obtain the center coordinate information of the third circular hole.

[0094] In some embodiments, the acquisition module 601 includes: The acquisition subunit is used to acquire the theoretical depth of the back-drill stop layer, the theoretical thickness of the circuit board, and the actual thickness of the circuit board; The fifth calculation unit is used to divide the actual thickness by the theoretical thickness to obtain the thickness ratio. The sixth calculation unit is used to multiply the theoretical depth by the thickness ratio to obtain the actual depth of the back-drilling stop layer.

[0095] In some embodiments, the acquisition module 601 includes: An image acquisition unit is used to acquire first image information of the first surface and first image information of the second surface of the circuit board. A center coordinate determination unit is used to determine the center coordinate information of the circular hole on the first surface and the center coordinate information of the circular hole on the second surface based on the first image information and the second image information. The matching unit is used to obtain the circular holes on the first surface and the second surface corresponding to each through hole by using a point set alignment algorithm based on the center coordinate information of the circular holes on the first surface and the center coordinate information of the circular holes on the second surface, so as to obtain the center coordinate information of the first circular hole on the first surface and the center coordinate information of the second circular hole on the second surface of the target through hole.

[0096] In some embodiments, the center coordinate determination unit includes: The first determining subunit is used to perform binarization processing on the first image information to obtain a first binarized image, determine the edge information of the circular hole on the first surface based on the first binarized image, and determine the center coordinate information of the circular hole on the first surface based on the edge information of the circular hole on the first surface. The second determining subunit is used to perform binarization processing on the second image information to obtain a second binarized image, determine the edge information of the circular hole on the second surface based on the second binarized image, and determine the center coordinate information of the circular hole on the second surface based on the edge information of the circular hole on the second surface.

[0097] In some embodiments, the acquisition module 601 includes: The first identification unit is used to identify a first number of circular holes on the first surface based on the first image information; The second identification unit is used to identify the second number of circular holes on the second surface based on the second image information; The detection unit is used to determine whether the first quantity and the second quantity are consistent.

[0098] It should be noted that the information interaction and execution process between the above-mentioned devices / units are based on the same concept as the method embodiments of this application. For details on their specific functions and technical effects, please refer to the method embodiments section, and they will not be repeated here.

[0099] In addition, the device for obtaining the back drill position described above can be a software unit, a hardware unit, or a combination of software and hardware. It can also be integrated into an electronic device as an independent accessory, or exist as an independent terminal device.

[0100] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0101] Figure 5 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Figure 5 As shown, the electronic device 3 in this embodiment may include: at least one processor 30 ( Figure 5 Only one processor 30, memory 31, and computer program 32 stored in memory 31 and executable on at least one processor 30 are shown. When the processor 30 executes the computer program 32, it implements the steps in any of the above method embodiments, or the processor 30 executes the computer program 32 to implement the functions of each module / unit in the above device or system embodiments.

[0102] For example, computer program 32 may be divided into one or more modules / units, one or more of which are stored in memory 31 and executed by processor 30 to complete this application. One or more modules / units may be a series of computer program 32 instruction segments capable of performing a specific function, which describe the execution process of computer program 32 in electronic device 3.

[0103] This application also provides a computer-readable storage medium storing a computer program 32, which, when executed by a processor 30, implements the steps described in the above-described method embodiments.

[0104] This application provides a computer program product that, when run on an electronic device, enables the electronic device to perform the steps described in the various method embodiments above.

[0105] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments of this application can be implemented by a computer program 32 instructing related hardware. The computer program 32 can be stored in a computer-readable storage medium, and when executed by the processor 30, it can implement the steps of the various method embodiments described above. The computer program 32 includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. A computer-readable medium can include at least: any entity or device capable of carrying computer program code to a terminal, a recording medium, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium. Examples include USB flash drives, portable hard drives, magnetic disks, or optical disks. In some jurisdictions, according to legislation and patent practice, computer-readable media cannot be electrical carrier signals or telecommunication signals.

[0106] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0107] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0108] In the embodiments provided in this application, it should be understood that the disclosed apparatus / network devices and methods can be implemented in other ways. For example, the apparatus / network device embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0109] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0110] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions 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 this application, and should all be included within the protection scope of this application.

Claims

1. A method for obtaining the position of a back drill, used on a circuit board having multiple through holes, characterized in that, include: Obtain the center coordinate information of the first circular hole on the first surface and the center coordinate information of the second circular hole on the second surface of the target through hole in the circuit board, as well as obtain the actual thickness of the circuit board and the actual depth of the back drill stop layer of the circuit board; Based on the center coordinate information of the first circular hole, the center coordinate information of the second circular hole, the actual depth, and the actual thickness, the center coordinate information of the third circular hole on the back-drilling stop layer of the target through hole is calculated, so as to determine the center coordinate information of the third circular hole as the back-drilling position when back-drilling the target through hole, wherein the target through hole is one or more of the through holes.

2. The method according to claim 1, characterized in that, The calculation of the center coordinate information of the third circular hole on the back-drill stop layer of the target through-hole on the circuit board based on the center coordinate information of the first circular hole, the center coordinate information of the second circular hole, the actual depth, and the actual thickness includes: The calculated ratio is obtained by dividing the actual depth by the actual thickness. The offset is obtained by subtracting the center coordinates of the first circular hole from the center coordinates of the second circular hole. Multiply the offset by the calculated ratio to obtain the corrected offset; The center coordinates of the third hole are obtained by adding the correction offset to the center coordinates of the first hole.

3. The method according to claim 2, characterized in that, The process of obtaining the actual thickness of the circuit board and the actual depth of the back-drill stop layer of the circuit board includes: Obtain the theoretical depth of the back-drill stop layer, the theoretical thickness of the circuit board, and the actual thickness of the circuit board; Divide the actual thickness by the theoretical thickness to obtain the thickness ratio; Multiplying the theoretical depth by the thickness ratio yields the actual depth of the back-drilling stop layer.

4. The method according to any one of claims 1 to 3, characterized in that, The target through-holes are formed as circular holes on the first surface and the second surface of the circuit board, respectively; The process of obtaining the center coordinate information of the first circular hole on the first surface and the center coordinate information of the second circular hole on the second surface of the target through hole in the circuit board includes: Acquire first image information of the first surface and first image information of the second surface of the circuit board; The center coordinates of the circular holes on the first surface and the center coordinates of the circular holes on the second surface are determined based on the first image information and the second image information. Based on the center coordinate information of the circular holes on the first surface and the center coordinate information of the circular holes on the second surface, a point set alignment algorithm is used to obtain the circular holes on the first surface and the circular holes on the second surface corresponding to each target through hole, so as to obtain the center coordinate information of the first circular hole on the first surface and the center coordinate information of the second circular hole on the second surface of the target through hole.

5. The method according to claim 4, characterized in that, Determining the center coordinates of the circular holes on the first surface and the second surface based on the first image information and the second image information includes: The first image information is binarized to obtain a first binarized image. The edge information of the circular hole on the first surface is determined based on the first binarized image, and the center coordinate information of the circular hole on the first surface is determined based on the edge information of the circular hole on the first surface. The second image information is binarized to obtain a second binarized image. The edge information of the circular hole on the second surface is determined based on the second binarized image, and the center coordinate information of the circular hole on the second surface is determined based on the edge information of the circular hole on the second surface.

6. The method according to claim 4, characterized in that, The method further includes: The first number of circular holes on the first surface is identified based on the first image information; The second number of circular holes on the second surface is identified based on the second image information; Determine whether the first quantity and the second quantity are consistent.

7. A back-drilling method, characterized in that, include: Obtain the back drill position obtained by the method for obtaining the back drill position according to any one of claims 1 to 6; The circuit board is back-drilled based on the back-drilling position.

8. A device for obtaining the position of a back drill, characterized in that, For circuit boards with multiple through holes, including: The acquisition module is used to acquire the center coordinate information of the first circular hole on the first surface and the center coordinate information of the second circular hole on the second surface of the target through hole in the circuit board, as well as to acquire the actual thickness of the circuit board and the actual depth of the back drill stop layer of the circuit board. The determining module is used to calculate the center coordinate information of the third circular hole on the back-drilling stop layer of the target through hole on the circuit board based on the center coordinate information of the first circular hole, the center coordinate information of the second circular hole, the actual depth, and the actual thickness, so as to determine the center coordinate information of the third circular hole as the back-drilling position when back-drilling the target through hole, wherein the target through hole is one or more of the through holes, and the back-drilling stop layer is a layer that prohibits drilling through the target through hole when back-drilling.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method as described in any one of claims 1 to 6 and / or the method as described in claim 7.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the method as described in any one of claims 1 to 6 and / or the method as described in claim 7.

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