PCB offset detection method

Abstract

The application provides a PCB offset detection method, and relates to the technical field of PCB detection, and comprises the following steps: S1, inputting a standard template; S2, acquiring a terminal area image of a to-be-detected panel and analyzing identifiable fixed technical features; S3, comparing the correlation parameters of the fixed technical features with the parameters of the standard template and calculating an offset value; S4, judging whether the offset value is within a qualified range; meanwhile, the detection method supports the combination of PCBs and FPCs with different features in the terminal area, the X and Y double-direction offset values are calculated, the adaptation range is widened, the detection precision is improved, and the missed detection and misjudgment rates are reduced.

Description

Technical Field

[0001] This application relates to the field of PCB inspection technology, and in particular to a method for detecting PCB misalignment. Background Technology

[0002] With the rapid development of the electronics and information industry, the bonding process of printed circuit boards (PCBs) and flexible printed circuit boards (FPCs) is widely used in high-precision electronic products, forming a multi-layered core component structure of "panel-PCB-FPC". The bonding accuracy of the PCB and FPC terminal areas directly determines the stability of signal transmission. Misalignment can cause faults such as poor contact and short circuits. Misalignment detection in this terminal area is a key link in quality control.

[0003] Existing automated testing equipment suffers from several pain points. For example, FPC material is soft and prone to wrinkling during adsorption, and the equipment is too long in the horizontal direction, resulting in insufficient workshop space. The back of the PCB carries a large number of components, which places stringent requirements on the structural design and level adjustment of the testing platform. Traditional platforms cannot meet the requirements for stable load-bearing and accurate positioning. The testing methods have poor adaptability and cannot be compatible with PCB-FPC combinations with different characteristics in the terminal area. Furthermore, the testing accuracy is insufficient and it is difficult to detect minute deviations. At the same time, traditional equipment has poor compatibility with multiple product specifications, low changeover efficiency, and the recycling of defective products can easily cause secondary damage to the components.

[0004] Currently, PCB-FPC bonding processes are evolving towards greater refinement, continuously increasing the demands on the rationality of the horizontal layout of testing equipment, the level accuracy of the platform, the adaptability to multiple features, and the precision of testing. Existing technologies can no longer meet these needs, necessitating a PCB misalignment detection device and method to complement our company's developed PCB misalignment detection equipment, achieving high-precision and highly adaptable PCB inspection of panels and ensuring the efficient and stable operation of the production line. Summary of the Invention

[0005] This invention proposes a PCB misalignment detection method to solve the technical problems of existing PCB detection methods, such as difficulty in adapting to PCB and FPC combinations with different characteristics of panel terminal areas, insufficient misalignment detection accuracy, and poor compatibility with multiple product specifications.

[0006] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0007] This invention provides a PCB misalignment detection method, comprising the following steps:

[0008] S1. Enter the standard template;

[0009] S2. Obtain an image of the terminal area of ​​the panel to be tested and analyze the identifiable fixing technical features;

[0010] S3. Compare the associated parameters of the fixed technical features with the parameters of the standard template and calculate the offset value;

[0011] S4. Determine whether the offset value is within the acceptable range;

[0012] In step S2, when there are regularly shaped patches at the left and right ends of the terminal area in the terminal area image, the A area located at the left and right ends of the terminal area image is detected, and the fixed technical features are set as the patches and the first side of the FPC, the first side of the PCB, the second side of the FPC and the second side of the PCB located in the A area.

[0013] In step S3, the actual distance from the center of the patch to the first edge of the FPC and the first edge of the PCB in the X direction is analyzed and calculated, and compared with the standard distance to calculate the first offset value; the actual distance from the center of the patch to the second edge of the FPC and the second edge of the PCB in the Y direction is analyzed and calculated, and compared with the standard distance to calculate the second offset value; it is then determined whether the first offset value and the second offset value are within the acceptable range.

[0014] Furthermore, in step S2, when no regularly shaped patches are detected at the left and right ends of the terminal area in the terminal area image, the B area of ​​the terminal area image is detected, and the fixed technical features are set as the third side of the FPC, the third side of the PCB, the fourth side of the FPC, and the fourth side of the PCB located in the B area.

[0015] In step S3, the actual distance between the third side of the FPC and the third side of the PCB in the X direction is measured and compared with the standard distance to calculate the third offset value; the actual distance between the fourth side of the FPC and the fourth side of the PCB in the Y direction is measured and compared with the standard distance to calculate the fourth offset value; and the third offset value and the fourth offset value are respectively determined to be within the acceptable range.

[0016] Furthermore, there are multiple B regions, which are distributed in the left, middle and right parts of the terminal area image.

[0017] Furthermore, before step S2, a pre-alignment step is also included: the detection platform carrying the panel to be detected moves to a position below the pre-alignment camera, the pre-alignment camera acquires an image of the panel to be detected, analyzes and calculates the positional deviation of the panel to be detected, and the detection platform performs compensation alignment based on the positional deviation.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] This invention provides a PCB misalignment detection method. By acquiring a precise image of the panel to be inspected, it can perform adaptive analysis and processing based on different PCB and FPC combinations with different characteristics in the terminal area. By calculating the X and Y misalignment values ​​under different conditions, it can determine whether the misalignment is qualified by judging whether the misalignment value exceeds the range. Furthermore, after changing the PCB and FPC combination with different characteristics, it is only necessary to re-enter the new standard template to cooperate well with the PCB inspection equipment for inspection, thereby broadening the adaptability range, improving the inspection accuracy, and reducing the rate of missed detections and false detections. Attached Figure Description

[0020] To more clearly illustrate the technical solution proposed by the present invention, a detailed description is provided below in conjunction with the embodiments and accompanying drawings. It should be understood that the accompanying drawings described below are merely some embodiments of the present invention, and those skilled in the art can make changes to these drawings under the concept of the present invention.

[0021] Figure 1 An assembly perspective view of an embodiment of the PCB misalignment detection device provided by the present invention;

[0022] Figure 2 An assembly perspective view of an embodiment of the loading arm provided by the present invention;

[0023] Figure 3 An assembly perspective view of an embodiment of the recycling unit provided by the present invention;

[0024] Figure 4 An assembly perspective view of an embodiment of the detection platform provided by the present invention;

[0025] Figure 5 An assembled perspective view of an embodiment of the panel to be tested provided by the present invention;

[0026] Figure 6 The image showing the detection result on the left side provided by this invention;

[0027] Figure 7 The image showing the detection result on the right side provided by this invention;

[0028] Figure 8 The image provided by this invention shows a patch-free detection result.

[0029] 1. Feeding platform; 2. Detection platform; 21. Adsorption panel; 22. Fourth adsorption component; 23. Fifth adsorption component; 3. Feeding arm; 31. Bending main arm; 32. First adsorption component; 33. Second adsorption component; 34. Third adsorption component; 35. Pressing component; 36. First profile rack; 37. Second profile rack; 38. Third profile rack; 39. Connecting plate; 4. Unloading arm; 5. Conveying arm; 6. Recycling unit; 61. Defective panel; 62. 63. Belt drive; 64. Handle; 65. Full material sensor; 7. Unloading sensor; 8. Detection camera; 9. Area A; 101. Patches; 11. First side of FPC; 12. First side of PCB; 13. Second side of FPC; 14. Second side of PCB; 15. Third side of FPC; 16. Third side of PCB; 17. Third side of PCB; 18. Fourth side of FPC; 19. Fourth side of PCB; 100. Area B; 101. First area; 102. Second area; 103. Third area. Detailed Implementation

[0030] See Figure 1-5 As shown, this embodiment provides a PCB and FPC misalignment detection device and detection method, which is applicable to the misalignment detection of the bonding area after the panel is bonded to the PCB and then bonded to the FPC for the second time.

[0031] like Figure 1 As shown, the loading arm 3 and unloading arm 4 are integrated on the same bracket, and both can move laterally along the bracket. The inspection platform 2 switches between the initial position, inspection position, first unloading position, and second unloading position via a vertical drive mechanism. The loading arm 3 can switch positions by moving laterally above the inspection platform 2 and the loading platform 1 when the inspection platform 2 is in the initial position. When the inspection platform 2 is in the initial position, the loading arm 3 transfers the panels to be inspected from the loading platform 1 to the inspection platform 2, thus loading the panels. When the inspection platform 2 is in the second unloading position, the unloading arm 4 transfers the qualified panels to be inspected from the inspection platform 2 to the next station. The conveying arm 5 is positioned between the inspection platform 2 and the recycling unit 6. When the inspection platform 2 is in the first unloading position, the conveying arm 5 transfers the unqualified panels to the recycling unit 6. Preferably, the recycling unit 6 is fixed to the upper left side of the inspection platform 2 and above the loading platform 1, forming a compact spatial layout.

[0032] like Figure 2 As shown, in this embodiment, the feeding arm 3 includes a bent main body arm 31 in the shape of a bent plate. The end of the bent main body arm 31 is connected to an adsorption component for adsorbing the panel to be tested. Through the bent structure design, the equipment cost is reduced while meeting the required stroke. (See...) Figure 5As shown, the panel to be tested consists of a first region 101, a second region 102, and a third region 103. The first region 101 is the panel body, the second region 102 is the bonding area from the panel body to the PCB, and the third region 103 is the bonding area from the PCB to the FPC. The adsorption assembly includes a first adsorption area for adsorbing the first region 101, a second adsorption area for adsorbing the second region 102, and a third adsorption area for adsorbing the third region 103. A pressing area is also provided between the second adsorption areas. Figure 2 As shown, the first adsorption area includes a first profile frame 36, on which an adjustable first adsorption component 32 is provided; the first profile frame 36 is vertically connected to a second profile frame 37, and the second profile frame 37 is parallelly fixed to a third profile frame 38 by multiple connecting plates 39. The second adsorption area includes a second adsorption component 33, and the third adsorption area includes a third adsorption component 34. The pressing area includes a pressing component 35, on which the second adsorption component 33, the third adsorption component 34, and the pressing component 35 are disposed. The third adsorption component 34 is arranged in opposite directions to the second adsorption component 33 and the pressing component 35. The pressing component 35 can be a hydraulic damper. The first adsorption component 32, the second adsorption component 33, and the third adsorption component 34 include inverted suction cups with different adsorption forces to ensure adsorption stability. Each time the test panel is handed over to the testing platform 2, the first adsorption area, the second adsorption area, and the third adsorption area of ​​the loading arm 3 adsorb the first area 101, the second area 102, and the third area 103 respectively. The pressing component 35 presses the third area 103, and the test panel is moved to the corresponding area of ​​the test panel adsorbed by the fourth adsorption area, the fifth adsorption area, and the sixth adsorption area of ​​the testing platform 2. Then the loading arm 3 breaks the vacuum, which can achieve stable adsorption and effectively prevent wrinkles from being generated during FPC adsorption.

[0033] like Figure 4As shown, in this embodiment, the detection platform 2 includes a fourth adsorption area supporting the first region 101, a fifth adsorption area supporting the second region 102, and a sixth adsorption area supporting the third region 103. The fourth and fifth adsorption areas are fixed to the detection platform 2 in parallel via mounting panels. The fifth and sixth adsorption areas are equipped with multiple fourth adsorption components 22 and fifth adsorption components 23 with adjustable lateral spacing. The fourth adsorption area includes an adsorption panel 21, with a rotating shaft mounting panel fixed to its bottom. Adjustable set screws are symmetrically arranged on both sides of the rotating shaft mounting panel, with the ends of the set screws fitting into the adsorption panel 21. Rotating the set screws allows for precise adjustment of the levelness of the corresponding adsorption area, meeting the high-precision flatness requirements for terminal area detection. Because the detection area is the third region 103, the flatness requirements for the fifth and sixth adsorption areas are extremely high. The adjustable set screws symmetrically arranged on both sides of the bottom of the adsorption panel 21 of the detection platform 2 are pre-calibrated, and the levelness of the platform is confirmed to meet the requirements using a level. The spacing between the adsorption components in the fifth and sixth adsorption areas is adjusted according to the distribution of components on the back of the PCB being inspected, avoiding interference between the components and the platform.

[0034] Multiple belts of the recycling unit 6 are arranged in parallel and wound around the drive roller shaft. A support plate is provided below the side of the belt bearing surface, which can contact the belt to support it. The belt drive 62 drives the drive roller shaft to rotate. Preferably, the belt drive 62 uses a stepper motor and a synchronous pulley for transmission. The synchronous pulley transmits the power of the stepper motor to the drive roller shaft, driving the belt to move in a directional manner. A pull handle 63 is fixed to the front of the belt. The sensing unit includes a full material sensor 64 at the front end of the belt and a discharge sensor 65 in the middle. Both move synchronously with the handle 63. When the belt is full, the full material sensor 64 at the front end triggers an alarm, and the operator can pull out the belt frame to clean the defective panel 61. The discharge sensor 65 in the middle monitors the discharge status in real time to prevent the conveyor arm 5 from discharging material, which could cause defective products to stack or break.

[0035] In a further preferred embodiment, this embodiment also includes a pre-alignment camera located in the area above the initial position and the detection position, and a detection camera 7 located above the detection position. When the detection platform 2 moves the panel to be inspected to below the pre-alignment camera, the pre-alignment camera takes a picture of the panel to be inspected on the detection platform, analyzes and processes the image to obtain the accurate position of the panel to be inspected compared with the system's preset position, obtains the deviation value, and transmits the deviation value to the control system. The control system controls the adsorption panel 21 to perform position compensation for the corresponding deviation value based on this deviation value, thereby aligning the panel to be inspected so that when the panel to be inspected is moved to the detection camera 7 by the detection platform 2, the panel to be inspected is exactly within the optimal field of view of the detection camera 7. After the detection camera 7 takes an image of the panel to be inspected, it analyzes and processes the image, compares it with the preset standard template data, and determines whether the panel to be inspected is qualified. Therefore, this application can meet the testing requirements of different specifications of PCB and FPC panels. It only requires updating the corresponding terminal area standard template through the control system. In terms of mechanical structure, it only requires adjusting the slider position of the first adsorption component 32 of the feeding arm 3, the spacing between the adsorption components of the fifth and sixth adsorption areas of the testing platform 2, and the recognition parameters of the pre-alignment camera. No modification to the main structure of the equipment is required to quickly complete the changeover and meet the testing requirements of multiple product specifications.

[0036] In addition, the detection method for PCB misalignment detection equipment was also disclosed. After the detection operation officially starts, the following steps should be followed:

[0037] S1. Loading: The upstream equipment places the panel to be tested onto the loading platform 1;

[0038] The loading arm 3 smoothly places the panel to be tested onto the loading platform 1 from the upstream equipment. The loading platform 1 then absorbs the panel, completing the loading process.

[0039] S2, Transfer: The inspection platform 2 is moved to the loading position, the loading arm 3 is moved above the inspection platform 2, and the panels to be inspected are placed from the loading platform 1 onto the inspection platform 2 in sequence;

[0040] The testing platform 2 moves to the loading position via a vertical drive mechanism, becoming flush with the surface of the loading platform 1. The loading arm 3 moves along a preset horizontal trajectory above the loading platform 1, and the three adsorption zones simultaneously activate to adsorb the corresponding areas of the panel to be tested. The hydraulic buffer in the pressing area gently presses the junction of the second area 102 and the third area 103 of the panel to be tested to prevent wrinkles from forming during FPC adsorption. After adsorption stabilizes, the loading arm 3 moves above the testing platform 2, precisely placing the panel to be tested in the corresponding adsorption area of ​​the testing platform 2. The adsorption components of the testing platform 2 immediately activate vacuum adsorption for fixation, and the loading arm 3 breaks the vacuum and resets. In this embodiment, the testing platform 2 is configured with two sets, alternating between loading and testing to improve overall testing efficiency.

[0041] S3, Pre-alignment: The detection platform 2 moves to the bottom of the pre-alignment camera to perform pre-alignment;

[0042] Next, the detection platform 2 moves vertically to directly below the pre-alignment camera and enters the pre-alignment stage to ensure that the third area 103 is within the field of view of the detection camera 7. The detection camera 7 is an area array camera with infrared ring light to provide a precise positioning reference for subsequent detection. The pre-alignment camera is located behind the detection camera 7.

[0043] S4. Inspection: The inspection platform 2 moves to the inspection position to perform PCB offset detection and determine whether the panel to be inspected is defective.

[0044] S4A, Input standard template; During testing, first input the standard template of the panel to be tested for this model through the control system, which includes the fixing technical features and standard distance data of the terminal area;

[0045] S4B. Locate the terminal area of ​​the panel to be inspected and identify the identifiable fixed technical features. The inspection camera 7 captures an image of the third area 103. If regular-shaped patches 81 (patches 81 can be of various types, such as circular or rectangular) are identified on the left and right sides of the terminal area, and if the patch 81 is circular, lock the position of area A 8 in the third area 103. It should be noted that area A also includes the first side 82 of the FPC, the first side 83 of the PCB, the second side 84 of the FPC, the second side 85 of the PCB, the third side 86 of the FPC, the third side 87 of the PCB, the fourth side 88 of the FPC, and the fourth side 89 of the PCB. When there are regular-shaped patches at the left and right ends of the terminal area in the terminal area image, the area A located at the left and right ends of the terminal area image is detected. The fixed technical features are set as the patches and the first side of the FPC, the first side of the PCB, the second side of the FPC, and the second side of the PCB located within a set range around the patches. It is then determined whether the first offset value and the second offset value are within the acceptable range. When no regularly shaped patches are detected at the left and right ends of the terminal area in the terminal area image, the B area of ​​the terminal area image is detected, and the fixed technical features are set as the third side of the FPC, the third side of the PCB, the fourth side of the FPC, and the fourth side of the PCB located in the B area.

[0046] S4C: Compare the fixed technical features with the standard template; when there are regularly shaped patches at both ends of the terminal area in the terminal area image, analyze and calculate the actual distance from the center of the patch to the first edge of the FPC and the first edge of the PCB in the X direction, and compare it with the standard distance to calculate the first offset value; analyze and calculate the actual distance from the center of the patch to the second edge of the FPC and the second edge of the PCB in the Y direction, and compare it with the standard distance to calculate the second offset value; when no regularly shaped patches are detected at the left and right ends of the terminal area in the terminal area image, measure the actual distance from the third edge of the FPC and the third edge of the PCB in the X direction, and compare it with the standard distance to calculate the third offset value; measure the actual distance from the fourth edge of the FPC and the fourth edge of the PCB in the Y direction, and compare it with the standard distance to calculate the fourth offset value; determine whether the third offset value and the fourth offset value are within the acceptable range.

[0047] S4D: Determine if the offset value is within the acceptable range. Specifically, compare the first, second, third, and fourth offset values ​​with the preset acceptable range, record the comparison results, and comprehensively verify the offset between the PCB and FPC terminal areas. That is, determine whether the above offset values ​​of the semi-finished product exceed the preset acceptable range. If they are within the preset acceptable range, they are judged as acceptable; if they exceed the preset acceptable range, they are judged as unacceptable.

[0048] S5. Unloading: When the test result of the panel to be tested is determined to be qualified in step S4D, the test platform 2 moves to the second unloading position, and the unloading arm 4 moves along the horizontal trajectory to the top of the test platform 2, adsorbs the qualified panel and then moves it to the downstream equipment to complete the unloading of qualified products.

[0049] S6. Unloading: When the test result of the panel to be tested is determined to be unqualified in step S4D, the testing platform 2 moves to the first unloading position, the conveyor arm 5 starts to adsorb the defective product and transfer it to the belt of the recycling unit 6. After the sensor detects that the defective product is placed in place, it sends a signal to the belt drive 62, which drives the belt to rotate and transport the defective product to the recycling area. When it is necessary to clean the defective product, the operator can easily clean it by pulling out the belt frame through the pull handle 63. The whole process realizes the automated and non-destructive recycling of defective products.

[0050] The testing equipment and method in this embodiment effectively solve problems such as adsorption wrinkles on the FPC panel to be tested, interference from components on the back of the PCB panel to be tested, poor testing adaptability, and insufficient accuracy, thus ensuring the efficient and stable operation of the testing process.

[0051] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0052] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0053] The above description represents specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and such modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A PCB offset detection method, characterized in that, The method comprises the following steps: S1, inputting a standard template; S2, acquiring a terminal area image of a panel to be detected, and analyzing a recognizable fixed technical feature; S3, comparing a correlation parameter of the fixed technical feature with a parameter of the standard template, and calculating an offset value; S4, judging whether the offset value is within a qualified range; In step S2, when the terminal area image has regular-shaped patches (81) at the left and right ends of the terminal area, an A area (8) at the left and right ends of the terminal area image is detected, and the fixed technical feature is set as the patches (81) and FPC first edge (82), PCB first edge (83), FPC second edge (84) and PCB second edge (85) in the A area (8); In step S3, the actual distances from the center of the patch (81) to the FPC first edge (82) and the PCB first edge (83) in the X direction are respectively analyzed and calculated, compared with standard distances, and a first offset value is calculated; the actual distances from the center of the patch (81) to the FPC second edge (84) and the PCB second edge (85) in the Y direction are analyzed and calculated, compared with standard distances, and a second offset value is calculated; whether the first offset value and the second offset value are within a qualified range is judged.

2. The PCB offset detection method of claim 1, wherein, In step S2, when the terminal area image does not detect regular-shaped patches (81) at the left and right ends of the terminal area, a B area (9) of the terminal area image is detected, and the fixed technical feature is set as FPC third edge (86), PCB third edge (87), FPC fourth edge (88) and PCB fourth edge (89) in the B area (9); In step S3, the actual distances of the FPC third edge (86) and the PCB third edge (87) in the X direction are measured, compared with standard distances, and a third offset value is calculated; the actual distances of the FPC fourth edge (88) and the PCB fourth edge (89) in the Y direction are measured, compared with standard distances, and a fourth offset value is calculated; whether the third offset value and the fourth offset value are within a qualified range is respectively judged.

3. The PCB offset detection method of claim 2, wherein, The B area (9) is multiple and distributed in the left part, the middle part and the right part of the terminal area image.

4. The PCB offset detection method of claim 1, wherein, Before step S2, a pre-alignment step is further included: a detection platform (2) carrying a panel to be detected moves to below a pre-alignment camera, the pre-alignment camera acquires an image of the panel to be detected, analyzes and calculates a position deviation of the panel to be detected, and the detection platform (2) is compensated and aligned according to the position deviation.

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