Printed circuit board detection system and method

Abstract

The invention discloses a printed circuit board detection system and method. The printed circuit board detection system comprises an automatic optical line measuring device and a line characteristic confirming device. The automatic optical line measuring device obtains line size information of a printed circuit board by shooting a line image of the printed circuit board. The line characteristic confirmation device is connected with the automatic optical line measuring device so as to obtain line size information. The circuit characteristic confirmation device obtains electrical characteristic information of the printed circuit board according to circuit reference characteristic information of a test sample plate and circuit size information of the printed circuit board. Resistance data or impedance data of the circuit are obtained through a non-contact automatic optical line measurement mode, the detection time of the whole circuit is shortened, data obtained through automatic optical line measurement are further corrected through line reference characteristic information obtained through the test sample plate, the resistance or impedance data are more accurate, and the detection accuracy is improved. And the detection efficiency and the detection effect are improved.

Description

Technical Field

[0001] The present invention relates to a printed circuit board detection system and method, and in particular to a printed circuit board detection system and method for performing correction based on circuit reference characteristic information of a test sample. Background Art

[0002] Printed circuit board (PCB) impedance refers to the total resistance composed of electrical parameters such as resistance, inductance and capacitance in the signal transmission line on the PCB. These parameters will affect factors such as signal transmission speed, waveform distortion, noise and power consumption. Therefore, controlling PCB impedance is important to ensure signal quality.

[0003] In high-speed data transmission and high-frequency circuit applications, it is particularly necessary to control the impedance of the PCB to ensure that the signal can be transmitted effectively and reduce signal distortion. Otherwise, the signal quality and transmission speed may be affected. Therefore, the purpose of measuring PCB impedance is to ensure that the PCB design meets the specification requirements and whether it needs to be adjusted and optimized so that the signal can be transmitted correctly.

[0004] PCB impedance is usually expressed in ohms (Ω), and the impedance ohm value is affected by many factors, such as the geometry of the transmission line, dielectric constant, signal frequency, etc. The design of high-end printed circuit board structure stacking, material matching, and whether the process parameters are appropriate and stable will have a significant impact on the quality of the finished product. In particular, the conduction mode and conduction reliability between layers have a crucial impact on the performance of the overall circuit board.

[0005] In order to test whether there are defects in the process of the printed circuit board and ensure the qualified rate of the printed circuit board, the general practice is to add a test sample to the design of the printed circuit board, usually located at the edge or corner of the printed circuit board. By testing these test samples, it is ensured that the manufacturing of the printed circuit board meets the standards and specifications, and the errors and defects in the production process are reduced. In order to determine whether the circuit characteristics of the printed circuit board meet the standards, the test sample is usually subjected to printed circuit board testing (PCB testing). This test mainly uses test points and test lines to contact the conductivity and insulation of the printed circuit board. It is used to confirm the resistance or impedance characteristics of the printed circuit board. This test method can be, for example, a flying probe test.

[0006] However, when using the contact test method, if the PCB impedance value does not meet the standard, it can only be known that a certain area or a certain line has defects, but it is impossible to know the actual location of the defect and perform repair work. In addition, when using the contact test method, every test point on a printed circuit board or test sample needs to be tested, and it takes a lot of time to complete the test of the entire board, resulting in reduced production efficiency. Summary of the invention

[0007] The main purpose of the present invention is to provide a printed circuit board inspection system, including an automatic optical circuit measurement device and a circuit characteristic confirmation device. The automatic optical circuit measurement device obtains circuit size information of the printed circuit board by photographing a circuit image of the printed circuit board. The circuit characteristic confirmation device is connected to the automatic optical circuit measurement device to obtain circuit size information. The circuit characteristic confirmation device obtains electrical characteristic information of the printed circuit board based on circuit reference characteristic information of a test sample and circuit size information of the printed circuit board.

[0008] Another object of the present invention is to provide a printed circuit board detection method, comprising: obtaining a circuit reference characteristic information based on a test sample of a printed circuit board; photographing a circuit image of the printed circuit board to obtain a circuit size information of the printed circuit board; and obtaining an electrical characteristic information of the printed circuit board based on the circuit reference characteristic information of the test sample and the circuit size information of the printed circuit board.

[0009] Therefore, the present invention obtains the resistance data or impedance data of the circuit by non-contact automatic optical circuit measurement, thereby reducing the detection time of the entire circuit, and further corrects the data obtained by the automatic optical circuit measurement through the circuit reference characteristic information obtained by the test sample (PCB testcoupon), so that the resistance or impedance data is more accurate, thereby improving the detection efficiency and detection effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a block diagram of the printed circuit board detection system of the present invention.

[0011] Figure 2 FIG. 4 is a block diagram of an embodiment of a printed circuit board inspection system of the present invention.

[0012] Figure 3 FIG. 4 is a block diagram of an embodiment of a contact measurement device in the present invention.

[0013] Figure 4 FIG. 4 is a block diagram of an automatic optical circuit measurement device according to an embodiment of the present invention.

[0014] Figure 5 FIG. 4 is a block diagram of an automatic optical circuit measurement device according to an embodiment of the present invention.

[0015] Figure 6 FIG. 1 is a schematic diagram of an optical configuration of an automatic optical circuit measurement device according to an embodiment of the present invention.

[0016] Figure 7 It is a cross-sectional schematic diagram of an embodiment of a printed circuit board circuit in the present invention.

[0017] Figure 8 The figure is a schematic diagram of the segmentation of multiple cross sections of an embodiment of a printed circuit board circuit in the present invention.

[0018] Fig. 9 It is a block diagram of an embodiment of a human detection device in the present invention.

[0019] Fig.10 It is a schematic diagram of an embodiment of a circuit board marking image in the present invention.

[0020] Fig.11 This is a diagram showing the impedance variation trend of a segment line in an embodiment of the present invention.

[0021] Fig.12 It is a flow chart of an embodiment of a printed circuit board detection method in the present invention.

[0022] Fig.13 FIG. 4 is a block diagram of another embodiment of a printed circuit board inspection system of the present invention.

[0023] Fig.14 FIG. 4 is a flow chart of another embodiment of the printed circuit board detection method of the present invention.

[0024] The following are marked in the figure:

[0025] A Printed Circuit Board

[0026] A1 circuit board body

[0027] A2 test sample

[0028] 100 PCB Inspection System

[0029] 10Automatic optical circuit measurement device

[0030] 11 Sensing unit

[0031] 111 Top view image capture device

[0032] 112 Side view image capture device

[0033] L optical axis direction

[0034] α Shooting angle

[0035] 12 Light Source

[0036] 13 Image measurement module

[0037] 20 Line characteristics confirmation device

[0038] 30Central Control System

[0039] 40 Contact measuring device

[0040] 41 Storage Devices

[0041] UW line upper width

[0042] DW line lower width

[0043] T Line Height

[0044] SW1 first side wall width

[0045] SW2 Second side wall width

[0046] 50 Defect marking device

[0047] 51 processors

[0048] 52 Storage device

[0049] T1 defect location module

[0050] T2 Image Labeling Module

[0051] PI PCB Image

[0052] D1 Coloring Area

[0053] D2 coloring area

[0054] 60 people inspection equipment

[0055] 200 PCB Inspection System

[0056] 70 Automatic optical line measurement device

[0057] 80 Line characteristics confirmation device DETAILED DESCRIPTION

[0058] The detailed description and technical content of the present invention are described as follows with reference to the accompanying drawings. The "one side" mentioned in the present invention can be the upper side, lower side, left side, right side, front side, rear side of the corresponding object, or set at any adjacent position of the object, or directly or indirectly connected to the object, etc., which is not limited in the present invention.

[0059] The various information and data described in the present invention can be stored in any non-temporary storage device, such as stored in a local server device or a cloud server device, which is not limited in the present invention; or the various information and data can be stored in the storage device of an individual device, or stored in the database of a central control system, which is also not limited in the present invention.

[0060] The "module" and the functions executed by the module described in the present invention can be loaded into a storage device by a single chip or a combination of multiple chips and then executed in coordination. The number of these chip configurations is not within the scope of the present invention. In addition, the chip described can be, but is not limited to, a combination of a processor (Processor), a central processing unit (CPU), a microprocessor (Microprocessor), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), etc., which is not limited in the present invention. The "storage device" described in the present invention can be, but is not limited to, a cache memory (Cache memory), a dynamic random access memory (DRAM), a persistent memory (Persistent Memory), etc., which can be used for storing and retrieving data, or a combination thereof, which is not limited in the present invention.

[0061] The following is a specific example for illustration. Figure 1 , is a block diagram of the printed circuit board inspection system of the present invention, as shown in the figure: the object to be inspected is a printed circuit board A, including a circuit board body A1 and a test coupon A2 (PCB test coupon) combined with one side of the circuit board body A1. The test coupon A2 is a small sample used to test the quality and performance of the circuit board body A1, generally arranged at the edge or corner of the circuit board body A1, and has the same various layers and characteristics as the circuit board body A1.

[0062] This embodiment discloses a printed circuit board inspection system 100, which mainly includes an automatic optical circuit measurement device 10, a circuit characteristic confirmation device 20 and a central control system 30. The automatic optical circuit measurement device 10 obtains the circuit size information of the circuit board body A1 by photographing the circuit image of the circuit board body A1. The circuit characteristic confirmation device 20 is connected to the automatic optical circuit measurement device 10 to obtain the circuit size information. The circuit characteristic confirmation device 20 obtains the electrical characteristic information of the circuit board body A1 based on the circuit reference characteristic information of the test sample A2 and the circuit size information of the circuit board body A1.

[0063] In one embodiment, the various parameters detected by the automatic optical circuit measurement device 10 can be transmitted to the central control system 30 (e.g., a programmable logic controller PLC), and the corresponding parameters are stored in a database (not shown in the figure) by the central control system 30, so that they can be retrieved from the database when needed. In another embodiment, the various parameters detected by the automatic optical circuit measurement device 10 can be stored in the server of each device, and the changes of these embodiments are not within the scope of the present invention. In one embodiment, the line reference characteristic information of the test sample A2 can also be stored in the database of the central control system 30 for retrieval. In this embodiment, the line reference characteristic information can include, but is not limited to, the sample line resistance data or the sample line impedance data.

[0064] Regarding one embodiment of the present invention, please refer to the following Figure 2 , Figure 3 and Figure 4 , is a block diagram of an embodiment of a printed circuit board detection system in the present invention, a block diagram of an embodiment of a contact measurement device in the present invention, and a block diagram of an embodiment of an automatic optical circuit measurement device in the present invention. As shown in the figure, in this embodiment, the circuit reference characteristic information of the test sample A2 can be obtained by a contact measurement device 40, and the contact measurement device 40 includes a storage device 41, which detects the test sample A2 by contact to obtain the sample circuit resistance data or sample circuit impedance data of the test sample A2. The contact measurement device 40 can be, for example, but not limited to a flying probe tester or other contact equipment, which is not limited in the present invention. In one embodiment, the contact measurement device 40 can include, for example, but not limited to a multimeter (DMM), an impedance analyzer (TDR instrument) or other similar devices, by connecting a test needle (Probe) to two or more test points on the test sample A2, measuring the sample circuit resistance data and / or the sample circuit impedance data, and storing the corresponding data in a database. In one embodiment, the obtained sample line resistance data or sample line impedance data may be stored in a storage device 41 disposed in the contact measurement device 40 , which is not limited in the present invention.

[0065] In this embodiment, the automatic optical circuit measurement device 10 generates calibration parameters based on the circuit reference characteristic information of the test sample A2 and the circuit dimension information of the circuit board body A1, and uses the calibration parameters to calibrate the electrical characteristic information of the circuit board body A1. The sample circuit resistance data and / or sample circuit impedance data obtained by the contact measurement device 40 will be used to correct the calibration parameters used by the automatic optical circuit measurement device 10 when measuring the circuit resistance data and / or the circuit impedance data.

[0066] like Figure 4As shown, the automatic optical circuit measurement device 10 obtains the circuit size information of the circuit board body A1 by photographing the circuit image of the circuit board body A1. The circuit size information includes the circuit width (for example, it may include but is not limited to the upper width of the circuit and the lower width of the circuit), the circuit height, the circuit length or the circuit cross-sectional area, which is not limited in the present invention. For one embodiment of the automatic optical circuit measurement device 10, please refer to Figure 5 , is a block diagram of an embodiment of an automatic optical circuit measurement device in the present invention. As shown in the figure, the automatic optical circuit measurement device 10 includes a sensing unit 11, a light source 12 and an image measurement module 13. The image measurement module 13 can be loaded into a storage device by a processor and executed. The image measurement module 13 is used to couple with the sensing unit 11 and generate circuit size information according to the circuit image.

[0067] The sensing unit 11 is aligned with the target area of ​​the circuit board body A1 to obtain the line image. Specifically, the sensing unit 11 can be set as an area scan camera (Area Scan Camera) or a line scan camera (Line Scan Camera), and the line image of the circuit board body A1 is captured by these camera devices. The target area refers to any area including the line on the circuit board body A1. In order to make it easy for the sensing unit 11 to obtain the line image on the circuit board body A1, the light source 12 can be used to properly illuminate the circuit board body A1.

[0068] In one embodiment, the image measurement module 13 has a corresponding image processing program for performing image processing functions. The image processing program may be, for example, an image pre-processing program, image segmentation and positioning, defect detection (gradient, region growth, growth compensation, etc.), machine learning system, deep learning system, etc., which are not limited in the present invention. The image measurement module 13 is coupled to the sensing unit 11 and generates line size information according to the line image.

[0069] The following is a detailed description of an embodiment of the optical configuration of the automatic optical circuit measurement device 10. Figure 6, is a schematic diagram of an optical configuration of an embodiment of an automatic optical circuit measurement device in the present invention. As shown in the figure, in this embodiment, the sensing unit 11 includes a top view image capture device 111 and at least one side view image capture device 112. The top view image capture device 111 is disposed on the top view side of the target area to obtain a top view image of the circuit image; the at least one side view image capture device 112 is disposed on the side view side of the target area so that the shooting direction of the at least one side view image capture device 112 maintains an appropriate inclination angle with the circuit on the circuit board body A1 to obtain a side view image of the circuit. In one embodiment, the side view image capture device 112 has an optical axis direction L, and has a shooting angle α with the plane of the circuit board body A1, and the shooting angle α is between 0 degrees and 90 degrees. In one embodiment, the number of the side view image capture device 112 is one, and in other embodiments, multiple side view image capture devices 112 may also be provided, and the multiple side view image capture devices 112 may have the same shooting angle α or different shooting angles α, and the design may be changed according to the detection requirements, which is not limited in the present invention.

[0070] Through the above configuration, the top view image capture device 111 and the side view image capture device 112 will respectively obtain the top view image and the side view image (hereinafter collectively referred to as the circuit image) of the circuit board body A1. Through these circuit images, the image measurement module 13 will be able to obtain the circuit size information of the circuit on the circuit board body A1.

[0071] The calculation procedure executed by the image measurement module 13 is described below.

[0072] The image measurement module 13 mainly generates line size information based on the line image. Specifically, when the processor loads and executes the program of the image measurement module 13, it analyzes the line image to obtain the first area image features (upper width and lower width) and the second area image features (side wall width) in the line image. Specifically, the image measurement module 13 can perform image pre-processing procedures (such as image enhancement, noise removal, contrast enhancement, edge enhancement, feature capture, image compression, image conversion, etc.), and segment or capture the boundary of the image after the image pre-processing procedure to divide the region of interest (ROI). The method of capturing the region of interest can be, for example, binarization, or through a machine learning system (Machine Learning), a deep learning system (DeepLearning) and other neural network-like training, and the first area image features and the second area image features are segmented from the image, which is not limited in the present invention. It should be noted that the line image described herein is not necessarily a single image, and it may also be two or more line images.

[0073] After acquiring the first region image features and the second region image features, the image measurement module 13 analyzes the first region image features and the second region image features to obtain the circuit dimension information of the circuit board body A1, including the circuit width, circuit height or circuit cross-sectional area. The following is a description of the method for obtaining the circuit dimension information. Figure 7 , is a cross-sectional schematic diagram of an embodiment of a printed circuit board circuit in the present invention. As shown in the figure, the circuit on the circuit board body A1 mainly includes the following groups of structural information: circuit upper width UW, circuit lower width DW, circuit height T, first side wall width SW1 and second side wall width SW2.

[0074] Taking the above-mentioned dual-lens embodiment (the top view image capture device 111 and the side view image capture device 112) as an example, through the above-mentioned optical configuration, the image measurement module 13 can obtain the line upper width UW, the line lower width DW, the first side wall width SW1, the second side wall width SW2 and the line height T through two sets of images taken at different orientations, and calculate and obtain the line cross-sectional area through these data.

[0075] In addition to obtaining the line size information through top view images and side view images, in another embodiment, the line size information can also be generated through 3D scanning technology (such as Time of Fight (TOF), triangulation, stereo vision method). These methods of obtaining line size information are not within the scope of the present invention.

[0076] In addition to the above embodiments, the line size information may also include, but is not limited to, line length and line volume. The line volume may be calculated from the line cross-sectional area and the line length. In a more accurate calculation method, the line volume may be calculated from the line cross-sectional area of ​​each sample and the line length of each sample.

[0077] The following is a description of the process of the circuit characteristic confirmation device 20 in this embodiment obtaining the electrical characteristic information of the circuit board body A1 with reference to the accompanying drawings.

[0078] First, see Figure 8 , is a schematic diagram of the segmentation of multiple cross sections of an embodiment of a printed circuit board circuit in the present invention. As shown in the figure, the circuit characteristic confirmation device 20 can generate corresponding electrical characteristic information based on the obtained circuit size information. Among them, the electrical characteristic information can include circuit resistance data or circuit impedance data. The circuit characteristic confirmation device 20 can generate circuit resistance data based on the circuit cross-sectional area and the circuit length. Specifically, the circuit resistance data can be obtained, for example, by the following resistance formula:

[0079]

[0080] Where R is the resistance value, ρ is the resistivity, L is the line length, A is the line cross-sectional area, and k0 is the correction parameter.

[0081] Based on the line size information, a line segment is cut into N parts, and the cross-sectional area data of each line segment SG1-SGN in the maximum resolution can be obtained. The resistance values ​​R1, R2…R corresponding to each small segment length L1-LN can be obtained through the previous equation. N After adding up, the line resistance data of the entire section line can be finally obtained, as shown in the following formula:

[0082]

[0083] Among them, A1-AN are the cross-sectional areas of each section of the line. It can be determined that as the resolution or sampling density increases, the measurement of the resistance value will generally become more accurate.

[0084] In a selected embodiment, taking a microstrip line structure (Micorstrip line) as an example, the line characteristic confirmation device 20 can generate line impedance value information based on the line width, line height, and the line dielectric layer thickness and line conductivity of the target area. Among them, the line dielectric layer thickness and line conductivity can be preset values ​​or obtained by the test sample A2 through other detection methods, and are not limited in the present invention. Specifically, the line characteristic confirmation device 20 includes but is not limited to, for example, using the Wadell equation, the IPC-2141 empirical formula or the calculation software developed by Polar Corporation to obtain impedance data.

[0085] The Wadell equation is as follows:

[0086]

[0087]

[0088] Where Z0 is the characteristic impedance of the microstrip line (unit: ohm); ε eff is the corrected dielectric constant of the medium used in the microstrip line; h is the thickness of the line dielectric layer; w′ is the corrected width of the microstrip line; k1 is the correction parameter.

[0089] The modified dielectric constant of the microstrip line is modified based on the following formula:

[0090]

[0091] Among them, ε ris the relative dielectric constant (Relative Dielectric Constant) of the medium used in the microstrip line; w is the effective width (Effective Width) of the microstrip line.

[0092] The microstrip line correction width is corrected based on the following formula:

[0093] w′=w+Δw′;

[0094]

[0095] Where w is the original microstrip line width, w′ is the corrected microstrip line width, Δw is the change in microstrip line width, Δw′ is the change in microstrip line width after correction, ε r is the relative dielectric constant of the medium used in the microstrip line, t is the thickness of the metal used in the microstrip line, and h is the thickness of the line dielectric layer.

[0096] IPC-2141 empirical formula is as follows:

[0097]

[0098] Where Z0 is the characteristic impedance of the microstrip line (unit: ohm); ε r is the relative dielectric constant (Relative Dielectric Constant) of the medium used in the microstrip line; h is the thickness of the line dielectric layer; w is the width (Width) of the microstrip line; t is the thickness (Thickness) of the metal used in the microstrip line; k2 is the correction parameter.

[0099] In addition to the impedance formula provided in the above embodiment, other calculation methods that can refer to and comply with the relevant standards such as IPC issued by the International Electronics Industry Connection Association can also be used, including but not limited to, for example, IPC-2221, IPC-2222, IPC-2223, IPC-2224, IPC-2225, IPC-2226, IPC-2227 and other related specifications. In another feasible embodiment, the line characteristic confirmation device 20 can also obtain impedance / resistance through a lookup table. In the lookup table, the values ​​that do not appear in the lookup table can be calculated by the nearest neighbor method (K-Nearest Neighbor) or the insertion method (Insertion Method), which depends on the design requirements.

[0100] Since some errors may occur in the automatic optical measurement method, in order to ensure the accuracy of the resistance or impedance measurement results, the above expression includes correction parameters k0, k1 and k2, which are used to correct the above expression based on the correction parameters k0, k1 and k2.

[0101] Specifically, the line characteristic confirmation device 20 can obtain the sample line resistance data or sample line impedance data of the test sample A1 through the contact measurement device 30, and adjust the correction parameters according to the line reference characteristic information such as the sample line resistance data or the sample line impedance data, so as to generate the line resistance data or the line impedance data based on the adjusted correction parameters when performing subsequent automatic optical detection.

[0102] In one embodiment, the circuit on the circuit board body A1 that is closest to the test sample A2 can be selected as the standard circuit for calculating the correction parameters. The "closest" mentioned above can be, for example, the closest position, the closest circuit type, the closest circuit size, the closest process environment conditions, and / or the closest circuit stacking type, which is not limited in the present invention. The correction parameters obtained by the standard circuit are used to be brought into the calculation formula so that the correction parameters can generate correct circuit resistance data or circuit impedance data.

[0103] For example, the resistance data obtained from the test sample A2 is R P , and the standard circuit on the circuit board body A1 calculates the theoretical resistance data R through the resistance formula q , and the resistance data R q The formula is as follows:

[0104]

[0105] The resistance data R obtained by calculating the standard circuit q The resistance data R obtained from the test sample A2 P The ratio between them is used to obtain the correction parameter k0, which is calculated as follows:

[0106]

[0107] Through the above formula, the resistance data of any circuit on the printed circuit board can be calculated based on equation (1) by adjusting the correction parameter k0.

[0108] If the impedance test data obtained by the test sample A2 is Z P , and the standard line on the circuit board body A1 uses the impedance formula: Wadell equation to calculate the theoretical impedance data Z q , and the impedance data Z q The formula is as follows:

[0109]

[0110] Impedance data Z obtained by calculating the standard line q The impedance test value Z obtained by test sample A2 P The correction parameter k1 is obtained by the ratio between the two, and the formula is as follows:

[0111]

[0112] Through the above formula, the impedance data of any circuit on the printed circuit board can be calculated based on equation (2) through the adjusted correction parameter k1.

[0113] In another embodiment, the theoretical impedance data Z is calculated by the IPC-2141 empirical formula w , impedance data Z w The formula is as follows:

[0114]

[0115] Impedance data Z obtained by calculating the standard line w The impedance test value Z obtained by test sample A2 P The correction parameter k2 is obtained by the ratio between them, and the formula is as follows:

[0116]

[0117] Through the above formula, the adjusted correction parameter k2 can be used to calculate the impedance data of any circuit on the printed circuit board based on equation (III).

[0118] In other embodiments, for example, the impedance electrical measurement data Z obtained by testing sample A2 P , obtain the impedance data Z of the standard line through the TDR impedance meter E , and then calculate the impedance data Z obtained by the standard line E The impedance test data Z obtained from the test sample A2 P The correction parameter k3 is obtained by the ratio between the two, and the formula is as follows:

[0119]

[0120] According to the above formula, the adjusted correction parameter k3 can be used to correct the impedance data of any circuit on the printed circuit board.

[0121] The present invention can also mark defects for human inspection equipment to review and re-inspect, please refer to Fig. 9 Fig.10 ,and Fig.11, which is a block diagram of an embodiment of the human inspection equipment in the present invention, a schematic diagram of an embodiment of the circuit board marking image in the present invention, and an impedance change trend diagram of an embodiment of the segment line in the present invention, as shown in the figure: In this embodiment, the printed circuit board inspection system of the present invention can further include a defect marking device 50 and a human inspection equipment 60.

[0122] The defect marking device 50 includes a processor 51 connected to a storage device 52, and executes a defect positioning module T1 and an image marking module T2. The detection of the defect positioning module T1 can be a specific point in the circuit, the entire circuit section or a specific section, or a selected circuit area surface or a full-plate detection, which can be performed according to actual needs. The defect positioning module T1 can confirm whether the corresponding circuit has a defect by setting a threshold (when the circuit resistance data or the circuit impedance data is lower or higher than a reasonable threshold range, such as ±10% of the expected resistance value or the expected impedance value), and store the defect position corresponding to the defect in the storage device 52. The defect position can be the coordinates of all pixels within the connected block range, or can be stored in the form of anchor point coordinates and pixel range, which is not limited in the present invention. In one embodiment, if the defect positioning module T1 performs a selected circuit area surface or full-plate detection, in order to avoid excessive calculation, the circuit size of the circuit board body A1 can be set to a threshold, and the abnormal size part can be found according to the threshold, and then the electrical characteristics of the abnormal part can be detected, so as to reduce the burden of calculation. In one embodiment, after completing the inspection of the selected circuit area or the entire board, the target object in the image can be directly clicked. After detecting the click, the defect location module T1 begins to obtain the electrical characteristic information of the target object based on the known circuit size information of the circuit board body A1 according to the position of the target object. This method can also reduce the computing burden.

[0123] After the defect location module T1 locates the defect position, the image marking module T2 can color the defect position and set an index based on the defect information (such as line resistance data or line impedance data) and the corresponding colored position, and transmit these data to the human inspection device 60 so that the defect can be manually inspected by the human inspection device 60.

[0124] The human inspection device 60 can be used to open the circuit board body image PI of the circuit board body A1 for visual inspection (such as Fig.10 As shown in FIG. 1 , when the cursor moves to the defect position (such as the colored area D1 and the colored area D2), various information of the line segment (including electrical characteristic information and line size information, etc.) can be displayed to confirm the defect of the corresponding segment line. In a further embodiment, the human inspection device 60 can draw the results of the corresponding continuous segment line into an impedance change trend diagram, such as Fig.11As shown, the vertical axis is the impedance value Zn and the horizontal axis is the line segment position Ln, so as to obtain the impedance trend of the entire section line.

[0125] The following is an example of the process of the printed circuit board detection method of the present invention. Fig.12 , is a flow chart of an embodiment of a printed circuit board detection method in the present invention. As shown in the figure, the printed circuit board parameter calibration of this embodiment mainly includes the following steps.

[0126] Step S01, first, based on the test sample of the printed circuit board, obtain the sample line resistance data or the sample line impedance data. In this embodiment, the sample line resistance data or the sample line impedance data is obtained by the contact measurement device 40 through the contact detection of the test sample A2 to obtain the sample line resistance data or the sample line impedance data of the test sample A2.

[0127] Step S02, photographing the circuit image of the printed circuit board to obtain circuit size information of the printed circuit board. In this embodiment, the circuit image of the circuit board body A1 is photographed by the automatic optical circuit measurement device 10 to obtain the circuit size information, and the circuit size information includes, but is not limited to, the upper width of the circuit, the lower width of the circuit, the height of the circuit, the length of the circuit, or the cross-sectional area of ​​the circuit. It is worth noting that step S01 and step S02 can be performed simultaneously, or step S02 can be performed first and then step S01, and the order of the two steps is not limited in the present invention.

[0128] Step S03, finally, the electrical characteristic information of the circuit board body is obtained according to the sample line resistance data or sample line impedance data of the test sample and the line size information of the circuit board body. In this embodiment, the circuit characteristic confirmation device 20 adjusts the correction parameters according to the sample line resistance data or sample line impedance data of the test sample A2, so as to generate the line resistance data or line impedance data of the circuit board body A1 according to the adjusted correction parameters during subsequent detection. Through the above steps, the line resistance data or line impedance data of the circuit board body A1 can be corrected based on the sample line resistance data or sample line impedance data of the test sample A2 to improve the accuracy of subsequent line measurement.

[0129] Another embodiment of the present invention is described below. Fig.13 and Fig.14, which is a block diagram of another embodiment of the printed circuit board detection system of the present invention and a flow diagram of another embodiment of the printed circuit board detection method of the present invention. As shown in the figure, the main difference between the printed circuit board detection system 200 of this embodiment and the previous embodiment is that the present invention uses an automatic optical circuit measurement device 70 to replace the contact measurement method to confirm the circuit reference characteristic information of the test sample A2, thereby obtaining the electrical characteristic information of the printed circuit board based on the circuit reference characteristic information and the circuit size information of the printed circuit board body A1. Since the hardware and software configuration of the automatic optical circuit measurement device 70 is basically the same as the automatic optical circuit measurement device 10 of the previous embodiment, the parts with the same hardware and software configuration will not be repeated in the following.

[0130] In this embodiment, the automatic optical circuit measurement device 70 obtains the circuit size information of the test sample A2 by photographing the circuit image of the test sample A2, and the circuit characteristic confirmation device 80 obtains the circuit reference characteristic information of the test sample A2 from the circuit size information of the test sample A2.

[0131] In this embodiment, the line reference characteristic information includes line conductivity and line dielectric layer thickness, and the line characteristic confirmation device 80 obtains the line reference characteristic information through the sample line size information, Wadell equation, IPC-2141 empirical formula and TDR impedance meter. The specific method is as follows: First, the automatic optical line measurement device 70 takes a line image of the test sample A2 to obtain the sample line size information of the test sample A2 (step S11); the sample line size information mentioned here includes the line width of the test sample A2 (for example, it can include but is not limited to the upper width of the line and the lower width of the line), line height, line length or line cross-sectional area.

[0132] Next, the circuit characteristic confirmation device 80 obtains the circuit conductivity and the circuit dielectric layer thickness based on the test sample A2 (step S12). Specifically, the circuit characteristic confirmation device 80 obtains the sample circuit size information and measures the average impedance Z of the microstrip line of the test sample A2 through the TDR impedance meter. o_mea , at this time, the sample line size information and Z o_mea Substituting into Wadell's equation:

[0133]

[0134]

[0135] Similarly, the average impedance Z o_mea Substitute the sample circuit size information into the IPC-2141 empirical formula:

[0136]

[0137] Since in the above equation, Z o_mea (average impedance), w (microstrip line width), and t (thickness of the metal used in the microstrip line) are all known, leaving only the line conductivity ε r The thickness of the circuit dielectric layer h has not yet been determined. At this time, by solving the simultaneous equations of the above equations (IV) and (V), the circuit conductivity ε can be obtained. r And the line dielectric layer thickness h is used as the line reference characteristic information.

[0138] Next, the automatic optical circuit measurement device 70 captures the circuit image of the circuit board body A1 to obtain the circuit size information of the circuit board body A1 (step S13); the circuit size information may include, but is not limited to, the upper width of the circuit, the lower width of the circuit, the height of the circuit, the length of the circuit, or the cross-sectional area of ​​the circuit. This step is the same as the method of capturing and obtaining the circuit size information by the automatic optical circuit measurement device 10 in the previous embodiment, so the same parts will not be repeated.

[0139] Finally, the circuit impedance information of the circuit board body A1 is obtained according to the circuit conductivity of the test sample, the circuit dielectric layer thickness and the circuit size information of the circuit board body A1 (step S14). In this step, since the circuit conductivity, the circuit dielectric layer thickness and the circuit size information of the circuit board body A1 are all determined, the circuit impedance information corrected according to the test sample can be obtained by substituting the corresponding values ​​into the Wadell equation, the IPC-2141 empirical formula or the Polar calculation software.

[0140] To summarize, the present invention obtains the resistance data or impedance data of the circuit by non-contact automatic optical circuit measurement, thereby reducing the detection time of the entire circuit, and further corrects the data obtained by the automatic optical circuit measurement through the circuit reference characteristic information obtained through the test sample (PCB test coupon), so that the resistance or impedance data is more accurate, thereby improving the detection efficiency and detection effect.

[0141] The present invention has been described in detail above. The above is only one preferred embodiment of the present invention and should not be used to limit the scope of the present invention. That is, all equivalent changes and modifications made according to the scope of the patent application of the present invention should still fall within the scope of the patent of the present invention.

Claims

1. A printed circuit board detection system, characterized in that: include: An automatic optical circuit measuring device, which obtains circuit size information of a printed circuit board by photographing a circuit image of the printed circuit board; as well as a circuit characteristic confirmation device connected to the automatic optical circuit measurement device to obtain the circuit dimension information; The circuit characteristic confirmation device obtains electrical characteristic information of the printed circuit board according to circuit reference characteristic information of a test sample and the circuit size information of the printed circuit board.

2. The printed circuit board detection system according to claim 1, characterized in that: The automatic optical circuit measurement device generates a correction parameter according to the circuit reference characteristic information of the test sample and the circuit size information of the printed circuit board, and uses the correction parameter to correct the electrical characteristic information of the printed circuit board, and the circuit reference characteristic information is a sample circuit resistance data or a sample circuit impedance data of the test sample.

3. The printed circuit board detection system according to claim 1, characterized in that: The automatic optical circuit measurement device obtains a sample circuit size information of the test sample by photographing the circuit image of the test sample, and the circuit characteristic confirmation device obtains the circuit reference characteristic information of the test sample from the sample circuit size information, and the circuit reference characteristic information is a circuit conductivity and a circuit dielectric layer thickness.

4. The printed circuit board detection system according to claim 1, characterized in that: The line dimension information includes a line upper width, a line lower width, a line height, a line length or a line cross-sectional area.

5. The printed circuit board detection system according to claim 4, characterized in that: The electrical characteristic information is line resistance data, and the line characteristic confirmation device generates the line resistance data according to the line cross-sectional area and the line length.

6. The printed circuit board detection system according to claim 4, characterized in that: The electrical characteristic information is line impedance data, and the line characteristic confirmation device generates the line impedance data according to the line upper width, the line lower width, the line height, and a line dielectric layer thickness and a line conductivity of the target area.

7. The printed circuit board inspection system according to claim 1, characterized in that: The sensing unit of the automatic optical circuit measurement device includes a top view image capture device and at least one side view image capture device. The top view image capture device is arranged on the top view direction side of the target area to obtain a top view image of the circuit image. The at least one side view image capture device is arranged on the side view direction side of the target area to obtain a side view image of the circuit image.

8. A printed circuit board detection method, characterized in that: include: Based on a test sample of a printed circuit board, obtaining line reference characteristic information; Taking a circuit image of the printed circuit board to obtain circuit size information of the printed circuit board; as well as According to the circuit reference characteristic information of the test sample and the circuit size information of the printed circuit board, electrical characteristic information of the printed circuit board is obtained.

9. The printed circuit board detection method according to claim 8, characterized in that: A correction parameter is generated according to the line reference characteristic information of the test sample and the line size information of the printed circuit board, and the electrical characteristic information of the printed circuit board is corrected by using the correction parameter, and the line reference characteristic information is a sample line resistance data or a sample line impedance data of the test sample.

10. The printed circuit board detection method according to claim 8, characterized in that: The circuit reference characteristic information of the test sample is obtained by taking a circuit image of the test sample to obtain a sample circuit size information of the test sample, and is obtained from the sample circuit size information, and the circuit reference characteristic information is a circuit conductivity and a circuit dielectric layer thickness.

11. The printed circuit board detection method according to claim 8, characterized in that: The line dimension information includes a line upper width, a line lower width, a line height, a line length or a line cross-sectional area.

12. The printed circuit board detection method according to claim 11, characterized in that: The line size information generates line resistance data according to the line cross-sectional area and the line length.

13. The printed circuit board detection method according to claim 11, characterized in that: The circuit dimension information generates circuit impedance data according to the circuit upper width, the circuit lower width, the circuit height, and a circuit dielectric layer thickness and a circuit conductivity of the printed circuit board.

14. The printed circuit board detection method according to claim 8, characterized in that: The circuit size information is obtained from a top view image and at least one side view image of the circuit image of the printed circuit board.

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