CN115575416A - Flexible circuit board pad detection method and system - Google Patents
Flexible circuit board pad detection method and system Download PDFInfo
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Abstract
The invention provides a method and a system for detecting a bonding pad of a flexible circuit board, wherein in the method for detecting the bonding pad of the flexible circuit board, a detection image of the flexible circuit board is collected, the detection image is divided into at least one region of interest, the boundary of the bonding pad in each region of interest is extracted to obtain an external graph of each bonding pad in each region of interest, a first area and a first central coordinate of the external graph of each bonding pad are obtained, the symmetry of the bonding pad in a bonding pad group is calculated, a second central coordinate of the bonding pad group is obtained according to the first central coordinate, the first area, the first central coordinate, the symmetry and the second central coordinate are compared with a first preset area, the first preset central coordinate, a preset symmetry and a second preset central coordinate one by one to determine the quality of the bonding pad in the region of interest, the defects of the bonding pad can be detected according to the position, the size and the symmetry of the bonding pad, the quantitative detection of the bonding pad is realized, and the bonding pad detection efficiency and precision are improved.
Description
Technical Field
The invention relates to the field of flexible circuit board quality detection, in particular to a method and a system for detecting a flexible circuit board bonding pad.
Background
Flexible Printed Circuit (FPC) has been widely used in electronic products, such as smart phones, liquid crystal televisions, tablet computers, new energy vehicles, and the like. With the development of science and technology, the FPC is also developed towards a thinner and higher density direction, so that the production defects are increased, and the detection difficulty is further improved. At present, the defect detection of the FPC mainly comprises the following three modes: manual visual inspection, scanning probe and high-precision automatic optical detection method. At present, most domestic manufacturers still adopt a manual visual inspection method, and the method needs workers to comprehensively and carefully inspect the whole substrate by using a magnifying lens, so that the inspection omission is easily caused, the efficiency is low, and the labor cost is greatly increased; the scanning probe detection technology is characterized in that an electron beam emitted by an electron gun is converged into a fine electron beam through an optical system to be focused on the surface of a sample, and the fine electron beam is repeatedly scanned on the surface of the sample to generate various information, so that a clear image can be obtained, but the efficiency is low, the equipment cost is high, and the popularization is difficult; compared with the former two detection methods, the automatic optical detection technology has obvious advantages, can greatly improve the detection speed, and has lower cost. Although many automatic optical detection devices exist at present, basically, the automatic optical detection devices can only detect some appearance defects of the FPC bonding pad, such as short circuit, burrs and the like, and cannot perform quantitative detection on the bonding pad.
Disclosure of Invention
The invention aims to provide a method and a system for detecting a bonding pad of a flexible circuit board, which can carry out quantitative detection on the bonding pad of the flexible circuit board and improve the bonding pad detection efficiency and precision.
In order to achieve the above object, the present invention provides a method for detecting a pad of a flexible circuit board, comprising:
collecting a detection image of the flexible circuit board;
dividing the detection image into at least one region of interest, wherein the region of interest comprises a pad group, and the pad group comprises at least two pads which are linearly arranged at intervals;
extracting the boundary of each bonding pad in each region of interest, and acquiring the external graph of each bonding pad in each region of interest according to the extracted boundary;
calculating a first area and a first center coordinate of an external graph of each bonding pad in each region of interest, calculating the area ratio between the external graphs of the bonding pads in the bonding pad group to obtain the symmetry of the bonding pads, and calculating a second center coordinate of the bonding pad group according to the first center coordinate of the bonding pads in the bonding pad group;
comparing the first area, the first center coordinate, the symmetry and the second center coordinate with preset parameters to determine the quality of the bonding pad of the region of interest, wherein the preset parameters comprise a first preset area and a first preset center coordinate of an external graph of the bonding pad, a preset symmetry of the bonding pad in the bonding pad group and a second preset center coordinate of the bonding pad group.
Optionally, the pad group includes a windowing region, the pads are linearly arranged in the windowing region at intervals, the windowing region is rectangular, and the preset parameters further include a third preset center coordinate of an external graph of the windowing region and a preset deviation value between the third preset center coordinate and the second preset center coordinate;
the method further comprises the following steps:
extracting the boundary of the windowing area and acquiring the external graph of the windowing area according to the boundary;
calculating a third center coordinate of the windowing area;
calculating the deviation value of the third center coordinate and the second center coordinate;
and comparing the deviation value with the preset deviation value.
Optionally, the preset parameters further include a second preset area, where the second preset area is a set area of the windowing area;
the method further comprises the following steps:
acquiring a second area of the windowing region according to an external graph of the windowing region in the pad group;
comparing the second area of the windowing area with the second preset area.
Optionally, the dividing the detection image into at least one region of interest includes:
performing threshold segmentation on the detection image according to a preset threshold;
and performing morphological processing on the detection image after threshold segmentation to segment the detection image into at least one region of interest.
Optionally, the acquiring the detection image of the flexible circuit board includes:
acquiring at least two images based on the movement of the shooting unit;
and splicing the images to obtain the detection image.
Optionally, the moving of the shooting unit along a first direction and a second direction to perform image acquisition on the flexible circuit board, where the first direction is perpendicular to the second direction, and the splicing the images to obtain the detection image includes:
establishing a rectangular coordinate system by taking a specific point of a first image acquired by the shooting unit as an origin and the moving direction of the shooting unit as a coordinate axis;
taking the corresponding position in each image as a characteristic point, and acquiring the coordinate of the characteristic point of the first image;
obtaining coordinates of the feature points of other images in the rectangular coordinate system according to the size of each image and the coordinates of the feature points of the first image;
and splicing each image in the rectangular coordinate system according to the coordinates of the characteristic points of each image.
Optionally, the acquiring the detection image of the flexible circuit board further includes:
performing smoothing filtering processing on the image to remove noise;
enhancing the contrast of the image.
Optionally, the flexible circuit board is provided with identification points, and a coordinate system is established according to the identification points to obtain the first central coordinate and the second central coordinate.
Optionally, the method for detecting the pad of the flexible circuit board further includes:
and importing a Gerber file of the flexible circuit board, wherein the Gerber file comprises the preset parameters.
In order to achieve the above object, the present invention further provides a flexible circuit board pad inspection system, including:
the acquisition module is used for acquiring a detection image of the flexible circuit board;
the image processing module is used for dividing the detection image into at least one interested area, the interested area comprises a pad group, and the pad group comprises at least two pads which are linearly arranged at intervals;
the boundary extraction module is used for extracting the boundary of each bonding pad in each region of interest and acquiring the external connection graph of each bonding pad in each region of interest according to the extracted boundary;
the processing module is used for calculating a first area and a first center coordinate of an external graph of each bonding pad in each region of interest, calculating the area ratio of the external graphs of the bonding pads in the bonding pad group to obtain the symmetry of the bonding pads, and calculating a second center coordinate of the bonding pad group according to the first center coordinate of the bonding pads in the bonding pad group;
and the judging module is used for comparing the first area, the first center coordinate, the symmetry and the second center coordinate with preset parameters to determine the quality of the bonding pad of the region of interest, wherein the preset parameters comprise a first preset area and a first preset center coordinate of an external graph of the bonding pad, a preset symmetry of the bonding pad in the bonding pad group and a second preset center coordinate of the bonding pad group.
The method comprises the steps of collecting a detection image of the flexible circuit board, dividing the detection image into at least one region of interest, extracting the boundary of a bonding pad in each region of interest, obtaining an external connection graph of each bonding pad in each region of interest according to the extracted boundary, obtaining a first area and a first central coordinate of the external connection graph of each bonding pad in each region of interest, calculating the area ratio of the external connection graphs of the bonding pads in a bonding pad group to obtain the symmetry of the bonding pad, obtaining a second central coordinate of the bonding pad group according to the first central coordinate, comparing the first area, the first central coordinate, the symmetry and the second central coordinate with a first preset area, a first preset central coordinate, a preset symmetry and a second preset central coordinate one by one to determine the quality of the bonding pad in the region of interest, detecting the defects of the bonding pad according to the position, the size and the symmetry of the bonding pad, realizing quantitative detection of the bonding pad, and improving the detection efficiency and the detection precision of the bonding pad.
Drawings
FIG. 1 is a flow chart of a method for detecting a pad of a flexible circuit board according to an embodiment of the invention.
Fig. 2 is a flowchart illustrating detection of a windowing region according to an embodiment of the present invention.
Fig. 3 is a flowchart of step S200 in fig. 1.
Fig. 4 is an image acquired by the photographing unit according to the embodiment of the present invention.
FIG. 5 is a detection image after morphological processing according to an embodiment of the invention.
Fig. 6a and 6b are schematic diagrams illustrating image stitching according to an embodiment of the present invention.
FIG. 7 is a block diagram of a flexible circuit board pad inspection system according to an embodiment of the present invention.
Detailed Description
In order to explain technical contents, structural features, and effects of the present invention in detail, the following description is made in conjunction with the embodiments and the accompanying drawings.
Descriptions such as "first," "second," etc. in this disclosure are for descriptive purposes only and are not to be construed as indicating or implying relative importance or to implicitly indicate the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In addition, the technical solutions in the embodiments of the present invention may be combined with each other, but it must be based on the realization of the technical solutions by those skilled in the art, and when the technical solutions are contradictory to each other or cannot be realized, such a combination of the technical solutions should not be considered to exist, and is not within the protection scope of the present invention.
It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The method for detecting the bonding pads of the flexible circuit board is suitable for the flexible circuit boards with the same bonding pad size, the same interval and the linear arrangement distribution in the same bonding pad group.
As shown in fig. 1, an embodiment of the present invention provides a method for detecting a pad of a flexible circuit board, including the following steps:
s100, collecting a detection image of the flexible circuit board.
At least two images (an image acquired by the shooting unit shown in fig. 4) can be acquired based on the movement of the shooting unit or the flexible circuit board, and the acquired images are spliced to obtain a detection image of the whole flexible circuit board. Because the relative movement speed of the shooting unit and the flexible circuit board is not completely uniform, when the movement speed is not matched with the line frequency of the shooting unit, the image collected by the shooting unit can be distorted, so that the collected image needs to be corrected, the correction is carried out according to parameters such as the movement speed, the resolution, the focal length, the object distance and the like, and the distortion correction of the image shot by the shooting unit belongs to the prior art, and is not repeated here.
It can be understood that the shooting unit may be a camera, and in order to improve the accuracy of the camera in acquiring images, before the camera starts to acquire images, the camera may be calibrated to solve the internal parameters, external parameters and distortion parameters of the camera, so as to prevent the acquired images from being deformed. The preprocessing of the images can be performed before image splicing or after the image splicing is completed.
It can be understood that the shooting unit can move along a first direction and a second direction to collect images of the flexible circuit board, and the first direction is perpendicular to the second direction. In order to improve the accuracy of image stitching, the acquired images may be converted into the same coordinate system for stitching, specifically, as shown in fig. 6a/6b, the coordinates of the feature points of the first image are obtained by using the corresponding positions in each image of the first image acquired by the shooting unit as the feature points; and obtaining the coordinates of the characteristic points of other images in the rectangular coordinate system according to the size of each image and the coordinates of the characteristic points of the first image, and splicing each image in the rectangular coordinate system according to the coordinates of the characteristic points of each image.
In some specific examples, the coordinates of the feature point of the first image are (x, y), the length of each image is h, the width of each image is w, and the coordinates of the feature point of the image acquired by moving the first image along the first direction are (x, y), (x, y + h), (x, y +2 h) \8230; (x, y + nh), that is, the image is acquired by moving the shooting unit along the first direction h; after the shooting unit moves s along the second direction, the characteristic point coordinates of the images collected continuously along the first direction are (x + s, y), (x + s, y + h), (x + s, y +2 h), (x + s, y +3 h) \ 8230: (x + s, y + nh); after the shooting unit moves s along the second direction, the feature point coordinates of the images collected continuously along the first direction are (x +2s, y), (x +2s, y + h), (x +2s, y + 2h), (x +2s, y + 3h) \ 8230, (x +2s, y + nh), and so on, the coordinates of the feature points of each image are obtained, and therefore the images are spliced in a rectangular coordinate system according to the feature point coordinates of each image to obtain a complete detection image.
More specifically, as shown in fig. 6a/6b, the lower left corner point of the first image is taken as the specific point of the first image, the specific point of each image is the lower left corner point thereof, the specific point is also taken as the feature point, the length of each image is h, the width of each image is w, the coordinate of the feature point of the first image is (0, 0), and the coordinates of the feature point of the image acquired by moving the image along the first direction are (0, 0), (0, h), (0, 2 h), (0, 3 h) \8230; (0, nh), respectively; after the shooting unit moves s along the second direction, the characteristic point coordinates of the images collected continuously along the first direction are (s, 0), (s, h), (s, 2 h), (s, 3 h) \8230; (s, nh) respectively; after the shooting unit moves s along the second direction, the characteristic point coordinates of the images collected continuously along the first direction are respectively (2s, 0), (2s, h), (2 s, 2 h), (2 s, 3 h) \8230; (2s, nh), and so on, the coordinates of the characteristic points of each image are obtained, and therefore the images are spliced in a rectangular coordinate system according to the characteristic point coordinates of each image to obtain a complete detection image. In the above specific example, each image captured by the capturing unit in the first direction does not have a repeatedly captured portion, each image captured in the second direction may or may not have a repeatedly captured portion, and when there is a repeatedly captured portion, the repeated portions may be subjected to fusion processing or the overlapped portion of one of the images may be removed for stitching, or the like.
Of course, in other specific examples, each image captured by the capturing unit along the first direction may have a repeated portion, and when having the repeated portion, the coordinate obtaining manner and the image stitching manner of moving the specific point of each captured image along the first direction are the same as those of the above-described image captured along the second direction.
Of course, for the shooting unit whose visual field can completely accommodate a complete flexible circuit board, the detection image may also be an image obtained by shooting the flexible circuit board once.
Further, in order to eliminate irrelevant information in the acquired image, enhance the detectability of relevant information, and simplify data information in the image, the acquired image may be preprocessed, which specifically includes: carrying out smoothing filtering processing on the acquired image to remove noise in the image; the contrast of the image is enhanced. Because the bonding pad in the flexible circuit board has color difference with the substrate, the bonding pad in the acquired image can be displayed more obviously through the pretreatment, and the reliability of the bonding pad identification is improved. In some specific examples, the contrast of the image may be enhanced by image multiplication, for example, in a Halcon environment, implemented by using a Mult _ image operator, g '= g1 × g2 × Mult + Add, where (g 1, g 2) respectively represent pixel values of the input image, g' is an output image (i.e., a detected image after enhancing the contrast), mult is a multiplier factor, and Add is an offset value, which has the effect of increasing the contrast of the image, i.e., white is more white and black is more white and less gray is pixels of intermediate gray values in the output image. Of course, in the embodiment of the present invention, the contrast of the detected image may be enhanced by other ways known to those skilled in the art, for example, histogram equalization, gray scale stretching, and the like, which is not limited in this respect.
S200, dividing the detection image into at least one interested area, wherein the interested area comprises a pad group, and the pad group comprises at least two pads which are linearly arranged at intervals.
As shown in fig. 4, the region of interest is a frame region shown in the figure, but of course, the region of interest may also be a larger area than the frame region in fig. 4, or may be a region in which a plurality of pad groups are framed. The pads in the pad group may be pads used for welding the same part in the flexible circuit board, or pads used for welding two opposite pins of the same part, or pads with a smaller distance in the flexible circuit board, or pads with the same row or column and the same pitch, etc., and the invention does not limit the pads in the pad group. By dividing the detection image into the interested area containing the pad group, image recognition and feature extraction are not carried out on other areas in the detection image, and the calculation amount can be reduced to improve the efficiency of pad detection.
S300, extracting the boundary of each bonding pad in each region of interest, and acquiring the external connection graph of each bonding pad in each region of interest according to the extracted boundary.
The boundary of each pad can be extracted by Canny edge detection, differential edge detection, roberts edge detection, sobel edge detection and other edge detection methods.
S400, calculating a first area and a first center coordinate of an external connection graph of each bonding pad in each region of interest, calculating the area ratio of the external connection graphs of the bonding pads in the bonding pad group to obtain the symmetry degree of the bonding pads, and calculating a second center coordinate of the bonding pad group according to the first center coordinate of the bonding pads in the bonding pad group.
The first area of the external graph of each bonding pad refers to the area of a region defined by the external graph of each bonding pad, and does not refer to the sum of the areas of the external graphs of all the bonding pads, but the area of a region surrounded by the external graphs of a single bonding pad; the first center coordinates are coordinates of a center point (first center as shown in fig. 4) of an area surrounded by the circumscribed figure of the single pad; the second center coordinates refer to coordinates of center points (center of pad shown in fig. 4) of all pads in the pad group, for example, when the pad group includes two pads, the second center coordinates are coordinates of center points between circumscribed patterns of the two pads, and when the pad group includes three pads, the first center coordinates are coordinates of center points (center point of pad located in the middle) between circumscribed patterns of the three pads; the symmetry degree refers to a ratio between first areas of the pads in the pad group, for example, when the pad group includes two pads, the symmetry degree refers to a ratio between first areas of two pads in the pad group, when the pad group includes three pads, the symmetry degree refers to a ratio between first areas of every two adjacent pads or a ratio between first areas of every two three pads, and the like.
In order to obtain the first center coordinate and the second center coordinate, a mark point may be set on the flexible circuit board, and the captured inspection image may establish a coordinate system according to the mark point, so as to obtain the first center coordinate and the second center coordinate, as shown in fig. 5, the mark point may be set at the upper left corner of the flexible circuit board, identify the mark point in the inspection image, and establish a coordinate system (not shown) with the mark point as an origin, so as to obtain the first center coordinate of each pad and the second center coordinate of each pad group. Wherein, the second central coordinate may be obtained according to the first central coordinate of each pad in the padset, for example, the first central coordinates of the two pads in fig. 5 are (X1, Y1) and (X2, Y2), and since the second central coordinate is the coordinate of the center point of the two pads, it may be obtained that the second central coordinate (X3, Y3) is ((X2-X1)/2 + X1, (Y2-Y1)/2 + Y1), and as shown in fig. 5, X1 and X2 are equal, so that the second central coordinate is (X1, (Y2-Y1)/2 + Y1), that is, X3= X1= X2, Y3= (Y2-Y1)/2 + Y1.
S500, comparing the first area, the first center coordinate, the symmetry and the second center coordinate with preset parameters to determine the quality of the bonding pad of the region of interest, wherein the preset parameters comprise a first preset area and a first preset center coordinate of an external graph of the bonding pad, a preset symmetry of the bonding pad in the bonding pad group and a second preset center coordinate of the bonding pad group.
It can be understood that the calculated first area, the first center coordinate, the second center coordinate and the symmetry are compared with the first preset area, the first preset center coordinate, the second preset center coordinate and the preset symmetry in a one-to-one correspondence manner, and the quality of the bonding pad in the region of interest is obtained according to the comparison result.
The preset parameter can be a preset range, and can be that the quality of the bonding pad is considered to be qualified when each calculated parameter falls within the corresponding preset parameter range, and the parameter of the bonding pad is considered to be unqualified and recorded when any obtained parameter is not within the corresponding preset parameter range; of course, the preset parameter may also be a fixed value, and the comparison is performed according to the preset parameter, the allowable error range, and the calculated parameter. For example, generally, the size of the pads in the same pad group is the same, the ratio of the areas between the external patterns of the pads in the pad group is 1 under the standard condition, that is, the preset symmetry of the pads may be 1, and of course, the preset symmetry may also be a range value, such as [0.98,1.02] and the like, when the pad group includes two pads, the ratio of the areas between the external patterns of the two pads is calculated to obtain the symmetry of the pads, when the symmetry falls to [0.98,1.02], the symmetry of the pad group is considered to be qualified, otherwise, the symmetry of the pad group is considered to be unqualified.
Generally, the flexible circuit board is provided with a windowing region, and the pads are disposed at the windowing region, that is, the pad group includes the windowing region and the pads disposed in the windowing region, and the pads in the pad group may be the pads disposed in the same windowing region.
Specifically, the same pad group of the flexible circuit board further includes a windowing region (as shown in fig. 4, generally, one pad group is provided with one windowing region), the pads are linearly arranged in the windowing region at intervals, and the windowing region is rectangular; the preset parameters further include a third preset center coordinate of the external graph of the windowing area and a preset deviation value between the third preset center coordinate and the second preset center coordinate, and therefore, as shown in fig. 2, the method for detecting the pad of the flexible circuit board may further include:
s600, extracting the boundary of the windowing area and obtaining the external graph of the windowing area according to the boundary.
And S700, calculating a third center coordinate in the windowing area.
And S800, calculating a deviation value of the third center coordinate and the second center coordinate.
And S900, comparing the deviation value with a preset deviation value.
Similarly, the third center coordinate refers to the coordinate of the center point (the third center as shown in fig. 5) of the area surrounded by the circumscribed figure of the windowing area; according to the property of the flexible circuit board, the center points of all the pads in the pad group are overlapped with the center point of the windowing area, so that the second center coordinate and the third center coordinate in the same pad group are the same, namely the preset deviation value can be 0, and of course, the preset deviation value can also be in the range of [ -0.03,0.03], [ -0.05,0.05] and the like which are close to 0. And comparing the deviation value with a preset deviation value, and when the deviation value is the same as the preset deviation value or the deviation value falls within the range of the preset deviation value, the deviation between the windowing area of the pad group and the pad is qualified, otherwise, the deviation is unqualified. Wherein the region of interest may be a region bounded by a circumscribed figure formed by the border of the windowed area (as shown by the boxed region of fig. 4).
Furthermore, the preset parameters further comprise a second preset area, and the second preset area is a set area of the windowing area; the flexible circuit board welding disc detection method also comprises the following steps:
acquiring a second area of the windowing region according to the external graph of the windowing region in the pad group;
and comparing the second areas of the windowing areas with second preset areas respectively.
The second area refers to the area of an area defined by the external graph of the window area in the pad group; and determining whether the area of the windowing area of the pad group is qualified or not by comparing the calculated second area with a second preset area.
In order to obtain the preset parameters conveniently, gerber files of the flexible circuit board can be directly imported, the Gerber files comprise the preset parameters, and therefore the preset parameters can be directly obtained from the Gerber files to conduct qualification judgment on the welding disc set.
In the method for detecting the bonding pads of the flexible circuit board, the detection image of the flexible circuit board is collected, the detection image is divided into at least one region of interest, the boundary of the bonding pad in each region of interest is extracted, the external connection graph of each bonding pad in each region of interest is obtained according to the extracted boundary, the first area and the first central coordinate of the external connection graph of each bonding pad in each region of interest are obtained, the area ratio of the external connection graphs of the bonding pads in the bonding pad group is calculated to obtain the symmetry of the bonding pad, the second central coordinate of the bonding pad group is obtained according to the first central coordinate, the first area, the first central coordinate, the symmetry and the second central coordinate are compared with the first preset area, the first preset central coordinate, the preset symmetry and the second preset central coordinate one by one to determine the quality of the bonding pads in the region of interest, the defects of the bonding pads can be detected according to the position, the size and the symmetry of the bonding pads, the quantitative detection of the bonding pads is realized, and the bonding pad detection efficiency and the detection precision are improved.
The method for detecting the flexible circuit board bonding pad provided by the embodiment of the invention can be suitable for detecting the quality of the bonding pad of the flexible circuit board of the Mini LED.
As shown in fig. 3, step S200 may specifically include:
and S210, performing threshold segmentation on the detected image according to a preset threshold.
As shown in fig. 4, since the color of the pad in the flexible circuit board is white and the color of the windowing is black, the detection image may be threshold-segmented by using a preset threshold, so as to perform feature extraction on the pad and the windowing in the detection image, the preset threshold may be one or more, the detection image is segmented into several parts according to the preset threshold, pixels belonging to the same part are regarded as the same object, the gray values of the pad in the detection image are the same or similar, and the gray values of the windowing are the same or similar, so that the pad and the windowing can be extracted (of course, when the region of interest only includes the pad, only the pad may be extracted). For example, the feature extraction may be performed on the pads and windows of the inspection image by global threshold segmentation using a gray histogram and a feature histogram.
And S220, performing morphological processing on the detection image after the threshold segmentation so as to segment the detection image into at least one region of interest.
As shown in fig. 5, by threshold segmentation, feature extraction may be performed on the pad and the window of the inspection image, so that the pad and the window are displayed clearly in the inspection image, and then morphological processing is performed, so as to outline an area of interest of the inspection image according to the boundary of the pad and the window, where each area of interest includes a pad group.
As shown in fig. 7, an embodiment of the present invention further provides a flexible circuit board pad inspection system, including:
the acquisition module 100, the acquisition module 100 is used for acquiring the detection image of the flexible circuit board.
The acquisition module 100 may include a camera and an image control unit, and the image control unit may be configured to control the camera to acquire an image of the flexible circuit board; for example, the image control unit may include a driving mechanism, and the driving mechanism is configured to drive the camera and the flexible circuit board to generate a relative movement therebetween, so as to capture an image of the flexible circuit board; specifically, the image control unit may include a control end, a driving mechanism, a mechanical platform and a vacuum pumping unit, wherein the driving mechanism may include a driving motor, the driving motor is controlled by the control end to operate, the camera may be disposed above the mechanical platform, the mechanical platform is used for placing a flexible circuit board, the vacuum pumping unit is used for fixing the flexible circuit board to prevent deviation in a motion process, the driving motor may be used for driving the mechanical platform to move to a photographing region, when the mechanical platform moves the flexible circuit board to the photographing region, the driving motor may drive the camera to move to photograph the flexible circuit board, and the driving motor driving the mechanical platform to move and the driving motor driving the camera to move may not be the same; the camera can be a linear array camera, the image control unit can further comprise a grating ruler, and the camera can trigger image acquisition by sending a pulse signal through the grating ruler. It can be understood that the control end may be provided with a human-computer interaction interface, and may perform parameter setting, or display a detection image, etc.
The image processing module 200, the image processing module 200 is configured to divide the inspection image into at least one region of interest, the region of interest includes a pad group, and the pad group includes at least two pads arranged at linear intervals.
And the boundary extraction module 300, wherein the boundary extraction module 300 is configured to extract boundaries of each pad in each region of interest, and obtain an external graph of each pad in each region of interest according to the extracted boundaries.
And the processing module 400 is configured to calculate a first area and a first center coordinate of the external graphics of each pad in each region of interest, calculate a ratio of areas between the external graphics of the pads in the pad group to obtain symmetry of the pads, and calculate a second center coordinate of the pad group according to the first center coordinate of the pads in the pad group.
The determining module 500 is configured to compare the first area, the first center coordinate, the symmetry, and the second center coordinate with preset parameters to determine the quality of the pad in the region of interest, where the preset parameters include a first preset area and a first preset center coordinate of an external graph of the pad, a preset symmetry of the pad in the pad group, and a second preset center coordinate of the pad group.
The above disclosure is only a preferred embodiment of the present invention, which is convenient for those skilled in the art to understand and implement, and certainly not to limit the scope of the present invention, therefore, the present invention is equally applicable to other embodiments, which are equivalent to the scope of the present invention.
Claims (10)
1. A method for detecting a pad of a flexible circuit board is characterized by comprising the following steps:
collecting a detection image of the flexible circuit board;
dividing the detection image into at least one region of interest, wherein the region of interest comprises a pad group, and the pad group comprises at least two pads which are linearly arranged at intervals;
extracting the boundary of each bonding pad in each region of interest, and acquiring the external connection graph of each bonding pad in each region of interest according to the extracted boundary;
calculating a first area and a first center coordinate of an external graph of each bonding pad in each region of interest, calculating the area ratio between the external graphs of the bonding pads in the bonding pad group to obtain the symmetry of the bonding pads, and calculating a second center coordinate of the bonding pad group according to the first center coordinate of the bonding pads in the bonding pad group;
and comparing the first area, the first center coordinate, the symmetry and the second center coordinate with preset parameters to determine the quality of the bonding pad of the region of interest, wherein the preset parameters comprise a first preset area and a first preset center coordinate of an external graph of the bonding pad, a preset symmetry of the bonding pad in the bonding pad group and a second preset center coordinate of the bonding pad group.
2. The method of claim 1, wherein the step of inspecting the pads of the flexible circuit board,
the pad group comprises a windowing area, the pads are linearly arranged in the windowing area at intervals, the windowing area is rectangular, and the preset parameters further comprise a third preset central coordinate of an external graph of the windowing area and a preset deviation value between the third preset central coordinate and the second preset central coordinate;
the method further comprises the following steps:
extracting the boundary of the windowing area and acquiring the external graph of the windowing area according to the boundary;
calculating a third center coordinate of the windowing area;
calculating the deviation values of the third center coordinate and the second center coordinate;
and comparing the deviation value with the preset deviation value.
3. The method of claim 2, wherein the step of inspecting the pads of the flexible circuit board,
the preset parameters further comprise a second preset area, and the second preset area is the set area of the windowing area;
the method further comprises the following steps:
acquiring a second area of the windowing region according to an external graph of the windowing region in the pad group;
comparing the second area of the windowing area with the second preset area.
4. The flexible circuit board pad inspection method of claim 1, wherein the dividing the inspection image into at least one region of interest comprises:
performing threshold segmentation on the detection image according to a preset threshold;
and performing morphological processing on the detection image after threshold segmentation to segment the detection image into at least one region of interest.
5. The method for detecting the bonding pad of the flexible circuit board according to claim 1, wherein the step of acquiring the detection image of the flexible circuit board comprises the steps of:
acquiring at least two images based on the movement of the shooting unit;
and splicing the images to obtain the detection image.
6. The method for detecting the bonding pad of the flexible circuit board according to claim 5, wherein the shooting unit moves along a first direction and a second direction to capture the image of the flexible circuit board, the first direction is perpendicular to the second direction, and the splicing the image to obtain the detection image comprises:
establishing a rectangular coordinate system by taking a specific point of a first image acquired by the shooting unit as an origin and the moving direction of the shooting unit as a coordinate axis;
taking the corresponding position in each image as a characteristic point, and acquiring the coordinate of the characteristic point of the first image;
obtaining coordinates of the feature points of other images in the rectangular coordinate system according to the size of each image and the coordinates of the feature points of the first image;
and splicing each image in the rectangular coordinate system according to the coordinates of the characteristic points of each image.
7. The method for inspecting the bonding pad of the flexible circuit board according to claim 5, wherein the capturing the inspection image of the flexible circuit board further comprises:
performing smoothing filtering processing on the image to remove noise;
enhancing the contrast of the image.
8. The method for detecting the bonding pad of the flexible circuit board according to claim 1, wherein the flexible circuit board is provided with a mark point, and a coordinate system is established according to the mark point to obtain the first central coordinate and the second central coordinate.
9. The flexible circuit board pad inspection method of claim 1, further comprising:
and importing a Gerber file of the flexible circuit board, wherein the Gerber file comprises the preset parameters.
10. A flexible circuit board pad inspection system, comprising:
the acquisition module is used for acquiring a detection image of the flexible circuit board;
the image processing module is used for dividing the detection image into at least one interested area, the interested area comprises a pad group, and the pad group comprises at least two pads which are linearly arranged at intervals;
the boundary extraction module is used for extracting the boundary of each bonding pad in each region of interest and acquiring the external connection graph of each bonding pad in each region of interest according to the extracted boundary;
the processing module is used for calculating a first area and a first center coordinate of an external graph of each bonding pad in each region of interest, calculating the area ratio of the external graphs of the bonding pads in the bonding pad group to obtain the symmetry of the bonding pads, and calculating a second center coordinate of the bonding pad group according to the first center coordinate of the bonding pads in the bonding pad group;
and the judging module is used for comparing the first area, the first center coordinate, the symmetry and the second center coordinate with preset parameters to determine the quality of the bonding pad of the region of interest, wherein the preset parameters comprise a first preset area and a first preset center coordinate of an external graph of the bonding pad, a preset symmetry of the bonding pad in the bonding pad group and a second preset center coordinate of the bonding pad group.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116079292A (en) * | 2023-01-31 | 2023-05-09 | 凌波微步半导体设备(常熟)有限公司 | Bonding pad identification method and semiconductor chip bonding wire machine |
| CN117571721A (en) * | 2024-01-15 | 2024-02-20 | 北京兆维智能装备有限公司 | Method and device for detecting surface defects of circuit board bonding pad and storage medium |
-
2022
- 2022-09-06 CN CN202211083564.7A patent/CN115575416A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116079292A (en) * | 2023-01-31 | 2023-05-09 | 凌波微步半导体设备(常熟)有限公司 | Bonding pad identification method and semiconductor chip bonding wire machine |
| CN116079292B (en) * | 2023-01-31 | 2024-01-23 | 凌波微步半导体设备(常熟)有限公司 | Bonding pad identification method and semiconductor chip bonding wire machine |
| CN117571721A (en) * | 2024-01-15 | 2024-02-20 | 北京兆维智能装备有限公司 | Method and device for detecting surface defects of circuit board bonding pad and storage medium |
| CN117571721B (en) * | 2024-01-15 | 2024-04-05 | 北京兆维智能装备有限公司 | Method and device for detecting surface defects of circuit board bonding pad and storage medium |
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