CN-121661053-B - Roll-to-roll high uniformity coating method for reinforcement of flexible circuit board

CN121661053BCN 121661053 BCN121661053 BCN 121661053BCN-121661053-B

Abstract

The invention discloses a roll-to-roll high-uniformity coating method for a reinforcing piece of a flexible circuit board, which relates to the technical field of coating of reinforcing pieces and comprises the following steps of: after the coating of the strip is finished, acquiring a gray line scanning image of the corresponding strip coating to obtain line scanning image data; performing adaptive image preprocessing based on line scanning image data, and adaptively acquiring a normal gray scale range of a strip coating to obtain normal gray scale range information; performing binarization processing on the line scanning image data according to the normal gray scale range information, and acquiring defect information in the image to obtain coating defect information; judging the uniformity of the strip coating, and carrying out corresponding early warning and recoating; the method is used for solving the problems that the prior reinforcement coating technology cannot adaptively set a reliable threshold range through a line scanning image of a strip coating when the uniformity of the coating of the reinforcement on the strip is detected, and the coating defect is reliably detected.

Inventors

WU XIPENG
WANG ZHENHUA
ZHU XIAOBAO

Assignees

深圳市盛鸿运科技有限公司

Dates

Publication Date: 20260508
Application Date: 20260206

Claims (3)

1. The roll-to-roll high uniformity coating method for the reinforcing piece of the flexible circuit board is characterized by comprising the following steps of: after the coating of the strip is finished, acquiring a gray line scanning image of the corresponding strip coating to obtain line scanning image data; performing adaptive image preprocessing based on line scanning image data, and adaptively acquiring a normal gray scale range of a strip coating to obtain normal gray scale range information; Performing binarization processing on the line scanning image data according to the normal gray scale range information, and acquiring defect information in the image to obtain coating defect information; judging the uniformity of the strip coating according to the defect information of the coating, and carrying out corresponding early warning and recoating; After the coating of the strip is finished, collecting a gray line scanning image of the corresponding strip coating, and obtaining line scanning image data comprises the following sub-steps: The method comprises the steps of marking a strip of a reinforcement of a flexible circuit board as a reinforcement strip, marking a coating layer coated by the reinforcement strip as a strip coating layer, and marking a device for coating the strip coating layer as a coating device; the line scanning device is used for acquiring one line of gray level images at any time and is used as a line scanning image; Setting the line frequency of the line scanning device as F0, continuously collecting line scanning images of the reinforcing piece strip coated with the strip coating according to F0, recording the line scanning images as line scanning image data, The line scanning image acquired at present is recorded as a current line scanning image, the line scanning image acquired k1 times before the current line scanning image is acquired and combined with the current line scanning image, and the line scanning image is recorded as current line scanning image data, wherein k1 is the set number; Performing adaptive image preprocessing based on line scanning image data, and adaptively acquiring a normal gray scale range of a strip coating to obtain normal gray scale range information, wherein the method comprises the following substeps: According to the current line scanning image data, all line scanning images are spliced into corresponding images according to the acquisition sequence and recorded as initial scanning images, and pixel points of each line of the initial scanning images are sequentially recorded as basic scanning lines 1 to k2, wherein k2=k1+1; setting the window size of one-dimensional median filtering as 3 multiplied by 1, carrying out one-dimensional median filtering on the basic scanning line 1, and sequentially repeating one-dimensional median filtering on all scanning lines in the initial scanning image to obtain a first scanning image after finishing; Respectively removing k3 columns of pixel points on the left side and k3 columns of pixel points on the right side of the first scanning image to obtain a second scanning image, and sequentially marking basic scanning lines 1 to k2 in the second scanning image as filtering scanning lines 1 to k2, wherein k3 is the set column number; for the filtering scanning line 1, k4 filtering scanning lines closest to the filtering scanning line 1 are taken to form an adjacent processing window of the filtering scanning line 1, wherein k4 is the set number; acquiring the median of gray values of all pixel points in the filtering scanning line 1, marking the median as a gray median, calculating corresponding median absolute deviation, and marking the median deviation as a median deviation MA; The pixel points with absolute deviation not larger than 2 xMA in the filtering scanning line 1 are recorded as background pixels, the background pixels of all the filtering scanning lines in all the adjacent processing windows are repeatedly obtained, and the median MG0 of the gray values of all the background pixels is obtained; Adding (MG 0-MG 1) the gray values of all the pixel points in the filtering scanning line 1, repeatedly processing all the pixel points of all the filtering scanning lines in the second scanning image, and obtaining a third scanning image after finishing the processing; Acquiring all background pixel points of all filtering scanning lines in a third scanning image, and acquiring the median of gray values of all the background pixel points in the third scanning image, wherein the median is recorded as a background median AE; The method comprises the steps of recording any pixel point in a third scanning image as a first pixel point, recording the gray value of the first pixel point as AF, acquiring the pixel points in 8 adjacent areas around the first pixel point as adjacent pixel points, acquiring the median BE of the gray value of the adjacent pixel points, calculating the corresponding median absolute deviation, and recording as MF; For any one neighborhood pixel point, if the absolute deviation between the corresponding gray value and BE is not less than 2 xMF, marking the pixel point as the corresponding neighborhood background pixel point, if the number of the neighborhood background pixel points in 8 neighborhood of the first pixel point is not less than k5, calculating AF- (BE-AE), and replacing AF, wherein k5 is the set number; Repeatedly processing all pixel points in the third scanning image to obtain a reference scanning image after finishing the processing; Acquiring the median of gray values of all background pixel points in a reference scanning image, and recording the median as a reference median WE; For any pixel point in the reference scanning image, if the absolute difference between the corresponding gray value and WE is not more than 2 XWR, marking the pixel as a candidate background pixel; for any one candidate background pixel, the number of corresponding neighborhood background pixel points is obtained in 8 neighborhood and is recorded as AN, if AN/9 is not smaller than k6, the pixel is marked as a coating pixel, wherein k6 is a set proportion threshold value; Obtaining the median VM and the corresponding median absolute deviation VA of gray values of all coating pixels, setting a threshold coefficient as e0, if VA is less than or equal to r1, making e0=2.5, if r1 is less than or equal to r2, making e0=3.0, if r2 is less than or equal to 2×r2, making e0=3.2, and if 2×r2 is less than or equal to VA, performing early warning, wherein r1 and r2 are set thresholds; if VA is less than or equal to 2 x r2, [ VM-e0 x VA, VM+e0 x VA ] is recorded as the coating gray scale range and is recorded as the normal gray scale range information.
2. The roll-to-roll high uniformity coating method for a stiffener of a flexible circuit board according to claim 1, wherein performing binarization processing on line scan image data according to normal gray scale range information and acquiring defect information in the image to obtain coating defect information comprises the sub-steps of: The pixel points of the reference scanning image, the gray values of which are not in the coating gray range, are marked as defective pixel points, and the pixel points of which the gray values are in the coating gray range are marked as coating pixel points; Performing binarization processing on the reference scanning image according to the defect pixel points and the coating pixel points to obtain a coating binary image, and obtaining a connected domain consisting of the defect pixel points in the coating binary image, and marking the connected domain as a defect area; Any one defective area is marked as a first area, the number of defective pixel points in the first area is marked as the number of pixels AX, and the number of pixels in all the defective areas is repeatedly obtained and marked as coating defect information.
3. The roll-to-roll high uniformity coating method for a flexible circuit board stiffener according to claim 2, wherein performing uniformity judgment on the strip coating according to the coating defect information, and performing corresponding pre-warning and re-coating comprises the sub-steps of: For the first area, if AX is smaller than k7, judging the first area as a false defect area, otherwise judging the first area as a true defect area, wherein k7 is a set number threshold; And if the true defect area exists in the reference scanning image, the uniformity of the strip coating in the current detection area is unqualified, early warning is carried out, and the strip coating is coated on the current detection area again.

Description

Roll-to-roll high uniformity coating method for reinforcement of flexible circuit board Technical Field The invention relates to the technical field of reinforcement piece coating, in particular to a roll-to-roll high-uniformity coating method for a flexible circuit board reinforcement piece. Background The coating technology of the reinforcing part is a core precise coating technology for manufacturing the reinforcing part of the flexible circuit board, and is a process technology overview of the core functions of continuously coating the surface of the substrate with a bonding type coating as a core through special coating equipment and technology, superposing a coating system with functions of heat conduction, shielding, bending resistance, temperature resistance and the like as required, detecting, gradient drying, post-processing and the like, realizing firm combination of the coating and the substrate, and finally endowing the reinforcing part with reliable bonding capability and the like to the FPC board. The existing reinforcement coating technology is used for detecting the uniformity of a coating on a strip, and usually relies on manual observation to detect the defects of the coating, or the defects of the coating are detected based on a fixed gray threshold by collecting gray images of the coating, most of the core defects of the reinforcement coating are tiny defects, such as pinholes and microbubbles, which are lower than the minimum resolution limit of human eyes, and cannot be completely identified by manual observation, macroscopic defects such as stripes, large area shrinkage holes and the like can be only found, the detection precision and the real-time performance are insufficient, and the defect judgment completely depends on experience and subjective judgment of a quality inspector, the judgment standard is different from person to person, the uniformity is poor, the defects of the coating are detected based on a fixed gray threshold, the uniformity of the external environment is required to be ensured when the defects of the coating are detected, the gray image background of the reinforcement coating can be dynamically fluctuated due to the brightness attenuation of a light source, the fluctuation of the coating, the coating speed, the tiny change of the coating thickness, the slight drifting of a camera, the fixed threshold is statically set, and the self-adaptive adjustment capability is not provided, and the defects of judging that if the threshold is excessively tight, normal pixels with the background fluctuation are misjudged as defects, the defects are easily judged to be detected when the defects of the coating is leaked, and the defects are easily detected on the strip, and the coating can not be adaptively detected by the prior art. Disclosure of Invention The invention aims to solve at least one of the technical problems in the prior art to a certain extent, acquires a corresponding gray line scanning image of a strip coating to obtain line scanning image data after the coating of the strip is finished, performs adaptive image preprocessing, adaptively acquires a normal gray range of the strip coating to obtain normal gray range information, performs binarization processing on the line scanning image data, acquires defect information in the image to obtain coating defect information, performs uniformity judgment on the strip coating, and performs corresponding early warning and recoating, so that the problem that the reliable threshold range cannot be adaptively set through the line scanning image of the strip coating to reliably detect the coating defect when the coating uniformity detection is performed on the reinforcing piece on the strip in the conventional reinforcing piece coating technology is solved. In order to achieve the above object, the present application provides a roll-to-roll high uniformity coating method for a reinforcing member of a flexible circuit board, comprising the steps of: after the coating of the strip is finished, acquiring a gray line scanning image of the corresponding strip coating to obtain line scanning image data; performing adaptive image preprocessing based on line scanning image data, and adaptively acquiring a normal gray scale range of a strip coating to obtain normal gray scale range information; Performing binarization processing on the line scanning image data according to the normal gray scale range information, and acquiring defect information in the image to obtain coating defect information; and judging the uniformity of the strip coating according to the defect information of the coating, and carrying out corresponding early warning and recoating. Further, after the coating of the strip is completed, collecting a gray line scanning image of the corresponding coating of the strip, and obtaining line scanning image data comprises the following sub-steps: The method comprises the steps of marking a strip of a reinforcement of a