TWI747464B - Method and equipment for hole position detection based on upper and lower drilling circuit boards - Google Patents

Abstract

Method and inspection equipment for hole position detection based on upper and lower drilling circuit boards, the method includes: judging whether the hole position is qualified according to a deviation of the upper and lower drilling holes and the depth of the holes; the inspection equipment provides an upper and lower light source supplementary light environment for the circuit board imaging, judging whether the hole position is penetrated, the deviation degree is qualified, and the hole depth is qualified according to front imaging information of the circuit board. The present disclosure comprehensively detects the hole quality of the circuit board, even if the top hole or bottom hole is inclined or the depth of the top hole and the bottom hole are inconsistent, the quality of the hole position of the circuit board can also be accurately measured.

Description

Hole position detection method and detection equipment based on upper and lower drilling circuit boards

The invention relates to the field of circuit board hole position detection, in particular to a hole position detection method and detection equipment based on upper and lower drilling circuit boards.

Nowadays, in the era of the highly developed electronics industry, the printed circuit board (PCB) has become one of the indispensable and important components in products such as computers and electronic communications. PCB drilling is one of the most advanced processes in printed circuit boards. The quality of the drilling directly affects the dozens of subsequent processes on the PCB. Therefore, how to control the quality of the drilling is now the focus of PCB electronics manufacturers.

The existing PCB drilling is mainly divided into mechanical drilling and laser drilling. As PCB circuit boards require higher precision and thinner thickness, the existing high-precision PCB circuit boards mainly use laser drilling. For through holes, blind holes, etc., in order to obtain better aperture requirements, it is necessary to use laser drilling from the upper and lower sides when processing the through holes. Since it is impossible to ensure that the upper and lower drilling holes are completely aligned, the upper and lower holes will appear. The phenomenon of hole offset, when the offset between the upper and lower holes exceeds the acceptable range, the PCB circuit board needs to be repaired or scrapped.

The publication number is CN106257232B, and the patent document titled “Detection Method of Hole Position Information and Inspection Equipment for Printed Circuit Boards” mentions a method that can detect the offset of upper and lower hole positions, as shown in Figure 7, but this method is only applicable When the upper hole is completely perpendicular to the PCB circuit board and the depth of the top hole and the bottom hole are the same (each occupies one-half of the thickness of the circuit board), once the upper hole or the lower hole is inclined (the same tapered hole) When the upper and lower circumferences are not concentrically arranged) or the depth of the top hole and the bottom hole are inconsistent (as shown in Figure 4 and Figure 5), the calculation result will be deviated, which will affect the true deviation between the top hole and the bottom hole. Judgment of displacement. In fact, it is difficult to ensure that the upper and lower drilling depths are exactly the same, and this will definitely affect the detection accuracy of the hole position information in the above prior art: take the coaxial hole in Figure 4 and Figure 5 as an example, according to the detection method in the prior art Obtain the hole position information of the hole position offset d of the first hole and the second hole: d=D1-(2*D13S)-D3, the result is not zero (more than 0 in Figure 4, Figure 5 The middle is less than 0). In fact, the centers of the top and bottom holes in Figures 4 and 5 are coaxial, that is, the offset is actually 0. Therefore, the prior art lacks a method for accurately detecting whether the hole position is qualified or not. And equipment.

In order to solve the problems of the prior art, the present invention provides a hole position detection method and detection device based on the upper and lower drilling circuit boards, which can ensure the gap between the top hole and the bottom hole regardless of whether the top hole or the bottom hole is drilled or not. Offset check The technical solution is as follows:

On the one hand, the present invention provides a hole position detection method based on up and down drilling of a circuit board, which is used to perform hole position offset detection on a target circuit board that has completed up and down drilling. The hole position detection method includes the following steps: step S11 , Under the light supplement state, obtain the front image of the target circuit board; step S12, analyze the front image, if the front image includes two circles, then perform step S13; if the front image If the image includes a complete circle and two intersecting arcs, step S14 and step S15 are executed; if the front image does not meet the above conditions, it is determined that the hole position of the target circuit board is unqualified; step S13, the calculation station The distance between the centers of the two circles in the front image. If the distance between the centers of the two circles is less than or equal to the preset first distance threshold, it is determined that the alignment of the holes of the target circuit board is qualified, otherwise it is determined that the The hole position of the target circuit board is unqualified; step S14, determine the first center of the circle where the first arc is located and the second center of the circle where the second arc is located; step S15, if the first center of the circle is the center of the complete circle The smaller of the distance between the center and the distance between the center of the second circle and the center of the complete circle is less than or equal to the preset first distance threshold, and the greater distance is less than or equal to the preset second The distance threshold, where the first distance threshold is less than or equal to the second distance threshold, the hole alignment of the target circuit board is determined to be qualified, otherwise the hole position of the target circuit board is determined to be unqualified.

Further, it is determined in step S15 that the hole positions of the target circuit board are aligned After the degree is qualified, it also includes: calculating the first radius of the circle where the first arc is located and the second radius of the circle where the second arc is located, if the smaller of the first radius and the second radius is the same as the complete If the ratio of the radius of the circle is greater than or equal to the preset ratio threshold, the hole position of the target circuit board is qualified, otherwise the hole position of the target circuit board is unqualified.

Further, after determining that the alignment of the holes of the target circuit board is qualified in step S13, the method further includes: calculating the radii of the two circles, if the ratio of the smaller radius to the larger radius is greater than or equal to a preset ratio threshold , The hole position of the target circuit board is qualified, otherwise the hole position of the target circuit board is unqualified.

Further, in step S14, at least three points are respectively taken on the first arc and the second arc, and the first center and the second circle of the circle where the first arc is located are determined by the coordinate method or the perpendicular method. The second center of the circle where the arc is located.

Further, the light supplement state in step S11 includes: simultaneously turning on the light source above the target circuit board and the backlight source below the target circuit board.

Further, according to the camera parameters used to obtain the front image of the target circuit board, the size ratio of the front image to the actual target circuit board is obtained, and the first distance threshold and the second distance threshold are preset according to the size ratio, or According to the size ratio, the distance data measured on the image is converted into the distance data on the actual circuit board.

On the other hand, the present invention provides another hole position detection method based on upper and lower drilling circuit boards, which is used to perform hole position offset detection on the target circuit board for which the upper and lower drilling holes are completed. The hole position detection method includes the following steps: Step S21: Acquire the front image of the target circuit board in the light-filled state; Step S22: Analyze the front image, and if the front image includes two circles, perform step S23; if the If the front image includes a complete circle and two intersecting arcs, step S24 and step S25 are executed; if the front image does not meet the above conditions, it is determined that the hole position of the target circuit board is unqualified; step S23, Calculate the radii of the two circles. If the ratio of the smaller radius to the larger radius is greater than or equal to the preset ratio threshold, the hole depth of the target circuit board is determined to be qualified, otherwise the hole position of the target circuit board The depth is unqualified; step S24, determine the first radius of the circle where the first arc is located and the second radius of the circle where the second arc is located; step S25, if the smaller of the first radius and the second radius is the same as the complete If the ratio of the radius of the circle is greater than or equal to the preset ratio threshold, it is determined that the hole depth of the target circuit board is qualified, otherwise the hole position of the target circuit board is unqualified.

Further, after determining that the hole depth of the target circuit board is qualified in step S25, the method further includes: determining the first center of the circle where the first arc is located and the second center of the circle where the second arc is located; The smaller of the distance between the center of the complete circle and the distance between the second center of the complete circle and the center of the complete circle is less than or equal to the preset first distance threshold, and the greater distance is less than or Equal to the preset second distance threshold, where the first distance threshold is less than or equal to the second distance threshold, it is determined that the hole position of the target circuit board is qualified, otherwise it is determined that the hole position of the target circuit board is not qualified.

Further, after determining that the hole depth of the target circuit board is qualified in step S23, the method further includes: calculating the distance between the centers of the two circles in the front image, if the distance between the centers of the two circles is less than or equal to a preset value For the first distance threshold, it is judged that the hole position of the target circuit board is qualified, otherwise it is judged that the hole position of the target circuit board is unqualified.

In yet another aspect, the present invention provides a hole position detection device based on up and down drilling circuit boards, which includes a backlight device, a plurality of upper light sources and an image acquisition device arranged above the backlight device, and the plurality of upper light sources emit The light is condensed on the backlight device, and the image acquisition device is arranged above the light converging point of the upper light source; the backlight device includes a plurality of independently controlled backlight panels, and each backlight panel has a The backlight source can be turned on or off independently, a plurality of the backlight boards are spliced and arranged to form a rectangular backlight area of different sizes, and the hole position detection device uses the hole position detection method as described above to detect the hole position deviation of the circuit board .

The present invention has the following beneficial effects:

Only need to collect the image from the top of the circuit board to be inspected, and the inspection result of the hole position quality of the upper and lower drilled circuit boards can be obtained through the image algorithm; it not only detects the deviation between the top hole and the bottom hole, but also Inspect the depth of the hole and comprehensively inspect the quality of the hole; whether the top hole or bottom hole is inclined, the accuracy of the hole quality detection can be ensured; whether the drilling depth of the top hole and the bottom hole are the same, the hole can be guaranteed Bit quality Accuracy of detection: It can determine the required opening area of the backlight board according to the size of the PCB board, and turn off the light source in the backlight area that is not needed, saving energy and avoiding the damage to human eyes by strong light.

1: Backlight device

11: Backlight board

12: Astigmatism layer

2: Upper light source

3: Image acquisition device

4: Circuit board

5: Compression device

6: Film board

S11, S12, S13, S14, S15, S21, S22, S23, S24, S25, S261, S262: steps

The subject matter deemed to be the present invention is specifically pointed out and clearly claimed in the concluding part of the specification. However, when referred to in conjunction with the accompanying drawings, the organization, operation method, subject, features, and advantages of the present invention can be best understood by referring to the following detailed description.

Fig. 1 is a flowchart of the first hole position detection method based on the upper and lower drilling circuit board provided by the embodiment of the present invention; Fig. 2 is the hole position detection equipment for detecting the upper and lower holes of the circuit board provided by the embodiment of the present invention Schematic diagram of the structure; FIG. 3 is a second hole detection method based on the upper and lower holes of the circuit board provided by the embodiment of the present invention; 5 is a cross-sectional view of the circuit board when the depth of the top hole is greater than the depth of the bottom hole according to an embodiment of the present invention; FIG. 6 is a schematic diagram of a front image including a complete circle and two intersecting arcs according to an embodiment of the present invention; The calculation principle diagram of the hole position detection method in the prior art; Fig. 8 is a schematic structural diagram of a hole position detection device with a light-scattering layer provided by an embodiment of the present invention; Fig. 9 is a schematic diagram of a splicing backlight plate with an L-shaped backlight plate provided by an embodiment of the present invention; Fig. 10 is provided by an embodiment of the present invention Schematic diagram of the splicing of backlight panels with back-shaped backlight panels.

In the following detailed description, many specific details are set forth in order to provide a thorough understanding of the present invention. However, those skilled in the art will understand that the present invention can be practiced without these specific details. In other cases, well-known methods, procedures and components have not been described in detail so as not to obscure the present invention.

The subject matter deemed to be the present invention is specifically pointed out and clearly claimed in the concluding part of the specification. However, when referred to in conjunction with the accompanying drawings, the organization, operation method, subject, features, and advantages of the present invention can be best understood by referring to the following detailed description.

It should be understood that, for simplicity and clarity of description, the elements shown in the figures are not necessarily drawn to scale. For example, for clarity, the size of some components may be exaggerated relative to other components.

Since the illustrative embodiments of the present invention can be implemented using electronic components and circuits well known to those skilled in the art to a large extent, as described above, the details will not be explained in greater detail outside the scope deemed necessary , In order to understand and appreciate the present invention Basic concepts, so as not to confuse or distract the teaching of the present invention.

The tapered hole obtained by drilling the circuit board, that is, the lower the hole is, the smaller the circumference of the hole. The hole position detection method based on the upper and lower drilling circuit board provided by the present invention not only detects the deviation between the upper and lower holes, but also detects the depth of the upper and lower holes. If the hole is drilled very shallowly, the hole position is also unqualified; on the contrary, even if the depth of the upper and lower holes is half the thickness of the circuit board, if the center of the two holes deviates too much, the hole position in this way is unqualified. The circuit board needs to be overhauled.

In one embodiment of the present invention, a hole position detection method based on upper and lower drilling circuit boards is provided, which is used to perform hole position offset detection on the target circuit board for which the upper and lower drilling holes are completed. The hole position offset is first detected. After detecting the depth of the hole position, referring to Fig. 1, the method for detecting the hole position includes the following steps:

Step S11: Obtain the front image of the target circuit board in the light supplement state.

Place the target circuit board on the hole position detection equipment shown in Figures 2 and 8. The hole position detection equipment includes a backlight device 1, a plurality of upper light sources 2 arranged above the backlight device 1, and image capture Device 3, the light emitted by the plurality of upper light sources 2 is converged on the backlight device 1, the image acquisition device 3 is arranged above the light converging point of the upper light source 2, the image acquisition device 3 is preferably a Charge-Coupled Device (CCD) camera.

As shown in Figures 9 and 10, the backlight device 1 includes a plurality of independently controlled backlight panels 11, and the backlight source on each backlight panel 11 can be independently turned on or off, and a plurality of the backlight panels 11 are spliced and formed. A variety of rectangular backlight areas of different sizes, allowing users to flexibly choose to turn on the backlight board according to the actual target circuit board size 11 To achieve the purpose of energy saving.

In a preferred embodiment of the present invention, the backlight device 1 further includes an astigmatism layer 12 arranged on the backlight plate 11, and the astigmatism layer 12 supports the circuit board 4 to be inspected, as shown in FIG. 8, The light scattering layer 12 is preferably an optical glass layer with a flatness requirement of 0.05 mm. The astigmatism layer 12 ensures the consistency of the light from the backlight 11 irradiating on each hole to be tested, and there will be no black spots, bright spots, etc., and the authenticity of the hole position information to be detected.

As shown in FIG. 2 or FIG. 8, the plurality of upper light sources 2 are linear light sources, the number of the upper light sources 2 is three or more, and the plurality of upper light sources 2 are on the backlight device 1. The light incident angle is the same (preferably, each upper light source 2 can independently adjust the direction of light emission), and the light source brightness of the multiple upper light sources 2 is adjustable to ensure that the hole position information is correctly fed back to the CCD camera.

Optionally, the plurality of upper light sources 2 can simultaneously move in a plane, and/or the backlight device 1 can move in a plane. In short, the upper light source 2 and the backlight device 1 can move relative to each other. For example, before the inspection, the PCB circuit board 4 with the drilled holes is placed on the backlight board 11 (more preferably on the astigmatism layer 12), and the area size corresponding to the backlight source is adjusted according to the size of the PCB circuit board 4. And use the pressing device 5 to press the PCB circuit board 4 to be tested on the backlight device 1, and then adjust and move the upper light source 2 or move the backlight device 1 (the backlight device 1 moves with the circuit board 4), possibly It is necessary to adjust the height distance between the upper light source 2 and the backlight device 1 until the convergence of the light emitted by the upper light source 2 is located in the area corresponding to the hole position of the circuit board 4 on the pressing device 5 (if there is no pressing device 5 , Then the light source 2 The emitted light is directly concentrated at the hole position of the circuit board 4). The pressing device 5 is preferably glass, so as not to affect the image acquisition by the image acquisition device 3.

After the CCD camera collects the hole position information on the PCB board, the inspection equipment can record the hole position picture and mark the coordinate information of each hole position in preparation for the subsequent determination of the hole quality.

As mentioned above, the splicing arrangement of the plurality of backlight plates 11 can form a variety of rectangular backlight areas of different sizes, and the implementation manners include but are not limited to the following two:

The first method: the backlight plate 11 includes a rectangular backlight plate and one or more L-shaped backlight plates of different sizes, as shown in FIG. 9, the rectangular backlight plate and the smallest size L-shaped backlight plate are adjacently spliced The L-shaped backlight plates are joined adjacently according to the size, and the outer edge of the smaller L-shaped backlight plate is joined with the inner edge of the larger L-shaped backlight plate.

The second method: The backlight plate 11 includes a rectangular backlight plate and one or more zigzag backlight plates of different sizes, as shown in FIG. 10, the inner edge of the rectangular backlight plate and the smallest zigzag backlight plate Adjacent splicing, the back-shaped backlight boards are connected adjacently according to the size, and the outer edge of the smaller back-shaped back light board is spliced with the inner edge of the larger back-shaped back light board.

That is to say, the embodiment of the present invention determines the required area of the backlight board according to the size of the PCB to be inspected, turns off the light source in the backlight area that is not needed, and combines the illumination of the light source to ensure that the hole position information is correctly fed back to the image acquisition device. Provide a good lighting environment for subsequent hole position inspection to improve the accuracy of hole position quality inspection.

Step S12: Analyze the front image, if the front image is If two circles are included, go to step S13; if the front image includes a complete circle and two intersecting arcs, as shown in FIG. 6, go to steps S14 and S15; if the front image does not satisfy The above conditions determine that the hole position of the target circuit board is unqualified.

That is to say, there are two necessary and insufficient conditions for the hole position of the target circuit board to be qualified. One is that two circles can be seen from the top of the circuit board (that is, the front image), where the large circle is the circumference above the top hole , The small circle may be the circumference below the top hole, or it may be the circumference above the bottom hole; in another case, you can see a circle that is two arcs in this circle when looking down on the circuit board, and the complete circle is the top hole On the upper circumference, one of the arcs is a part of the circumference below the top hole, and the other arc is a part of the circumference above the bottom hole. In other cases, such as blind holes, the front image of the image is a circle, and the other front image is a complete circle and a hole with an arc is judged as a hole position unqualified.

Step S13: Calculate the distance between the centers of the two circles in the front image, and if the distance between the centers of the two circles is less than or equal to the preset first distance threshold, determine the alignment of the holes of the target circuit board Qualified, otherwise it is determined that the hole position of the target circuit board is unqualified.

The first distance threshold is the same as the first distance threshold in the following step S15, and is an allowable range for judging whether the drilling is inclined, that is, the offset between the upper edge and the lower edge of the top hole.

As mentioned at the beginning of the embodiment, in addition to judging the hole alignment, it is also necessary to judge whether the drilling depth is qualified. Only when the hole alignment and the drilling depth are both qualified, the hole position of the circuit board can be judged as qualified. Therefore, The target circuit board is determined in step S13 After the hole alignment is qualified, it also includes:

Calculate the radii of the two circles. If the ratio of the smaller radius to the larger radius is greater than or equal to the preset ratio threshold, the hole position of the target circuit board is qualified, otherwise the hole position of the target circuit board is unqualified . As mentioned above, the hole on the circuit board is a tapered hole, as shown in Figure 4 and Figure 5. The ratio of the circumference of the upper and lower edges of the hole reflects the depth of the hole. A minimum standard (proportion threshold) is set. The ratio of the smaller radius to the larger radius of the circle is lower than this minimum standard, indicating that the smaller radius is too small, that is, the hole is drilled too deep, and the hole depth is unqualified, that is, the hole is unqualified.

Step S14: Take at least three points on each intersecting arc to determine the first center of the circle where the first arc is located and the second center of the circle where the second arc is located.

For the situation where there is a complete circle and two arcs in the front image, because the intersection of the two arcs is the result of the intersection of the circle under the top hole and the circle above the bottom hole, it must be a through hole, and according to (not in a straight line) (Of) Three points can determine a circle and its center are common knowledge. For example, the points of the three points are connected by two to form a line segment. The intersection of the vertical lines among the three line segments is the center of the circle. The intersection point to three points The distance between any point in is the radius. Or establish a coordinate system, obtain the coordinates of three points, and establish a two-dimensional quadratic equation system. The coordinate point with the same distance to these three points is the center of the circle, and the calculated equal distance is the radius. Alternatively, the known least square method (Sun of Least Suqares) or Hough Transform (Hough Transform) can also be used to calculate the center of the circle where each arc is located.

Step S15. If the smaller of the distance between the first circle center and the center of the complete circle and the distance between the second circle center and the center of the complete circle is less than or equal to At a preset first distance threshold, and the larger distance among them is less than or equal to the preset second distance threshold, wherein the first distance threshold is less than or equal to the second distance threshold, then the target circuit is determined The hole position alignment of the board is qualified, otherwise the hole position of the target circuit board is judged to be unqualified.

第一距離閾值，且|C3-C1|

第二距離閾值，則判定電路板之孔位對準度合格。 Assuming that the center of a complete circle is C1, the first center of the circle where the first arc is located is C2, and the second center of the circle where the second arc is located is C3, determine the distance between the center of the circle |C2-C1| and The size of |C3-C1|, if |C2-C1| is small, it is determined that C2 is the center of the circumference under the top hole, and C3 is the center of the circumference above the bottom hole. A first distance threshold and a second distance threshold are preset, wherein the first distance threshold is less than or equal to the second distance threshold, and the first distance threshold is used to determine whether the borehole is inclined, that is, the upper edge and the lower edge of the top hole The allowable range of edge offset. If |C2-C1|=0, it means that the drilling is not inclined. If |C2-C1| exceeds the first distance threshold, the hole position of the circuit board is judged to be unqualified; The second distance threshold is the allowable range for judging the offset of the top hole and the bottom hole. If |C3-C1|=0, then the two holes have no offset. If |C3-C1| exceeds the second distance threshold, then Determine the hole position of the circuit board as unqualified; only meet |C2-C1|

The first distance threshold, and |C3-C1|

The second distance threshold determines that the hole alignment of the circuit board is qualified.

As mentioned at the beginning of the embodiment, in addition to judging the hole alignment, it is also necessary to judge whether the drilling depth is qualified. Only when the hole alignment and the drilling depth are both qualified, the hole position of the circuit board can be judged as qualified. Therefore, After determining that the hole alignment of the target circuit board is qualified in step S15, the method further includes: calculating the first radius of the circle where the first arc is located and the circle where the second arc is located If the ratio of the smaller of the first radius and the second radius to the radius of the complete circle is greater than or equal to the preset ratio threshold, the hole position of the target circuit board is qualified, otherwise The hole position of the target circuit board is unqualified.

The above distance values need to be converted. Specifically, according to the camera parameters used to obtain the front image of the target circuit board, the size ratio between the front image and the actual target circuit board is obtained, and the first size ratio is preset according to the size ratio. The distance threshold value and the second distance threshold value or the distance data measured on the image are converted into distance data on the actual circuit board according to the size ratio. That is, for example, the size ratio between the front image and the actual target circuit board is N:1. One conversion method is to convert the distance data measured on the image (divided by N) into the distance data on the actual circuit board, and then compare it with the actual standard Threshold comparison, another conversion method is to convert the actual standard threshold (multiplied by N) into a threshold for comparison with the distance data measured on the image.

In another embodiment of the present invention, the present invention provides another hole position detection method based on the upper and lower drilling circuit board, which is used to detect the hole position offset of the target circuit board after the upper and lower drilling is completed. The hole position is first detected In case of deviation, the depth of the hole position is detected afterwards. See Fig. 3. The hole position detection method includes the following steps:

Step S21: Acquire the front image of the target circuit board in the light supplement state.

Place the target circuit board on the hole position detection equipment as shown in FIG. The upper light source 2 has a symmetrical arrangement structure, the image acquisition device 3 is arranged above the backlight plate 1 and at the symmetry axis of the upper light source 2, the target circuit board is placed on the backlight plate 1, and the upper light source is turned on at the same time 2 and backlight Plate 1, preferably, a layer of transparent thin plate (not shown) can be prevented between the circuit board and the backlight plate to disperse the light emitted by the backlight plate 1, so that the light is evenly distributed, and ensures that the light emitted by the backlight plate 1 is irradiated In the consistency of the tested holes, there will be no black spots and bright spots, so as to ensure that the information of the hole position is accurately fed back to the image acquisition device 3 (such as a CCD camera).

Step S22: Analyze the front image. If the front image includes two circles, execute S23; if the front image includes a complete circle and two intersecting arcs, as shown in FIG. 6 If shown, S24 and S25 are executed; if the front image does not meet the above conditions, it is determined that the hole position of the target circuit board is unqualified.

That is to say, there are two necessary and insufficient conditions for the hole position of the target circuit board to be qualified. One is that two circles can be seen from the top of the circuit board (that is, the front image), where the large circle is the circumference above the top hole , The small circle may be the circumference below the top hole, or it may be the circumference above the bottom hole; in another case, you can see a circle that is two arcs in this circle when looking down on the circuit board, and the complete circle is the top hole On the upper circumference, one of the arcs is a part of the circumference below the top hole, and the other arc is a part of the circumference above the bottom hole. Other situations are judged as unqualified hole positions, such as a blind hole with a circle on the front, and a hole with a complete circle and an arc on the front, and so on.

Step S23. Calculate the radii of the two circles. If the ratio of the smaller radius to the larger radius is greater than or equal to the preset ratio threshold, then it is determined that the hole depth of the target circuit board is qualified, otherwise the target circuit board The hole position is unqualified.

As mentioned above, the hole on the circuit board is a tapered hole, as shown in Figure 4 and Figure 5. The ratio of the circumference of the upper and lower edges of the hole reflects the depth of the hole. Set a minimum Low standard (proportion threshold). If the ratio of the smaller radius to the larger radius of the two circles is lower than this minimum standard, it means that the smaller radius is too small, that is, the drilling is too deep, and the hole depth is unqualified, that is, the hole position is not qualified. qualified.

As mentioned at the beginning of the embodiment, in addition to judging the drilling depth, it is also necessary to judge whether the hole alignment is qualified. Only when the hole alignment and the drilling depth are both qualified, the hole position of the circuit board can be judged as qualified. Therefore, After determining that the hole depth of the target circuit board is qualified in step S23, the method further includes: calculating the distance between the centers of the two circles in the front image, if the distance between the centers of the two circles is less than or equal to the preset first distance Threshold, it is judged that the hole position of the target circuit board is qualified, otherwise it is judged that the hole position of the target circuit board is unqualified. The first distance threshold here is the same as the first distance threshold in the following step S262, and is used to determine whether the drilling is inclined, that is, the allowable range of the offset between the upper edge and the lower edge of the top hole.

Step S24: Take at least three points on each of the intersecting arcs to determine the first radius of the circle where the first arc is located and the second radius of the circle where the second arc is located.

For the situation where there is a complete circle and two arcs in the front image, because the intersection of the two arcs is the result of the intersection of the circle under the top hole and the circle above the bottom hole, it must be a through hole, and according to (not in a straight line) (Of) Three points can determine a circle and its center system. For example, using the vertical method: the points of the three points are connected by two to form a line segment, and the intersection of the vertical lines among the three line segments is the center of the circle. The intersection point The distance to any one of the three points is the radius. Or use the coordinate method: establish a coordinate system, get the coordinates of three points, establish a two-dimensional quadratic equation system, find the coordinate point with the same distance to these three points is the center of the circle, and the calculated equal distance is the radius . Or, you can also use Known least square method (Sun of Least Suqares) or Hough Transform (Hough Transform), calculate the center of the circle where each arc is located, and then calculate the first radius of the circle where the first arc is located and where the second arc is located The second radius of the circle.

Step S25. If the ratio of the smaller radius of the first radius and the second radius to the radius of the complete circle is greater than or equal to the preset ratio threshold, then it is determined that the hole depth of the target circuit board is qualified, otherwise the The hole position of the target circuit board is unqualified.

As mentioned at the beginning of the embodiment, in addition to judging the drilling depth, it is also necessary to judge whether the hole alignment is qualified. Only when the hole alignment and the drilling depth are both qualified, the hole position of the circuit board can be judged as qualified. Therefore, After determining that the hole depth of the target circuit board is qualified, the method further includes: step S261, determining the first center of the circle where the first arc is located and the second center of the circle where the second arc is located; The smaller of the distance between the center of the complete circle and the distance between the second center of the complete circle and the center of the complete circle is less than or equal to the preset first distance threshold, and the greater distance is less than or It is equal to the preset second distance threshold, where the first distance threshold is less than or equal to the second distance threshold, the hole position of the target circuit board is determined to be qualified, otherwise the hole position of the target circuit board is determined to be unqualified.

第一距離閾值，且|C3-C1|

第二距離閾值，則判定電路板之孔位對準度合格。 Assuming that the center of a complete circle is C1, the first center of the circle where the first arc is located is C2, and the second center of the circle where the second arc is located is C3, determine the distance between the center of the circle |C2-C1| and The size of |C3-C1|, where |C2-C1| is the distance between the center C1 and the center C2, |C3-C1| is the distance between the center C3 and the center C1, if |C2- C1| is smaller , It is judged that C2 is the center of the circle below the top hole, and C3 is the center of the circle above the bottom hole. A first distance threshold and a second distance threshold are preset, wherein the first distance threshold is less than or equal to the second distance threshold, and the first distance threshold is used to determine whether the borehole is inclined, that is, the upper edge and the lower edge of the top hole The allowable range of edge offset. If |C2-C1|=0, it means that the drilling is not inclined. If |C2-C1| exceeds the first distance threshold, the hole position of the circuit board is judged to be unqualified; The second distance threshold is the allowable range for judging the offset of the top hole and the bottom hole. If |C3-C1|=0, then the two holes have no offset. If |C3-C1| exceeds the second distance threshold, then Determine the hole position of the circuit board as unqualified; only meet |C2-C1|

The first distance threshold, and |C3-C1|

The second distance threshold determines that the hole alignment of the circuit board is qualified.

The invention discloses a hole position detection method and detection equipment based on upper and lower drilling circuit boards, which can judge whether the hole positions are qualified from the deviation of the upper and lower drilling holes and the depth of the holes. Use the front imaging information of the circuit board to determine whether the hole position is penetrated, the deviation degree is qualified, and the hole depth is qualified. The present invention comprehensively detects the quality of the hole positions of the circuit board. Using the detection method of the present invention, even when the top hole or bottom hole is inclined or the depth of the top hole and the bottom hole are inconsistent, it can also accurately Measure the quality of the holes on the circuit board.

In addition, those skilled in the art will realize that the boundaries between the above operations are only exemplary. Multiple operations can be combined into a single operation, a single operation can be distributed in additional operations, and operations can be performed at least partially overlapping times. In addition, alternative embodiments may include multiple illustrations of specific operations, and the order of operations may be changed in various other embodiments.

However, other modifications, changes and substitutions are also possible. Therefore, the description and drawings should be viewed in an exemplary rather than restrictive sense.

In the claim statement, any reference signs placed between parentheses shall not be regarded as restrictive claims. The word "comprising" does not exclude the existence of other elements or steps listed in the claims. In addition, the term "a" or "an" as used herein is defined as one or more than one. Unless otherwise stated, terms such as "first" and "second" are used to arbitrarily distinguish the elements described by these terms. Therefore, these terms are not necessarily intended to indicate the timing or other priority of these elements. The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used.

Although certain features of the present invention have been illustrated and described herein, those of ordinary skill in the art will now think of many modifications, substitutions, changes and equivalents. Therefore, it should be understood that the appended claims are intended to cover all these modifications and changes that fall within the true spirit of the present invention.

11: Backlight board

2: Upper light source

3: Image acquisition device

4: Circuit board

Claims (10)

A hole position detection method based on up and down drilling circuit boards, used to detect the hole position offset of the target circuit board that has completed the up and down drilling, even if the upper hole or the lower hole is drilled or the upper hole and the lower hole are drilled If the depth is inconsistent, the hole position detection method includes the following steps: step S11, in the light supplement state, obtain the front image of the target circuit board; step S12, analyze the front image, if the front image is If two circles are included, step S13 is executed; if the frontal image includes a complete circle and two intersecting arcs, then steps S14 and S15 are executed; if the frontal image does not meet the above conditions, it is determined that all The hole position of the target circuit board is unqualified; step S13, the distance between the centers of the two circles in the front image is calculated, and if the distance between the centers of the two circles is less than or equal to the preset first distance threshold, it is determined The hole alignment of the target circuit board is qualified, otherwise the hole position of the target circuit board is determined to be unqualified; step S14, determine the first center of the circle where the first arc is located and the second center of the circle where the second arc is located And step S15, if the smaller of the distance between the first circle center and the center of the complete circle and the distance between the second circle center and the center of the complete circle is less than or equal to the preset first distance threshold , And the larger distance among them is less than or equal to the preset second distance threshold, where the first distance threshold is less than or equal to the second distance threshold, then it is determined that the hole alignment of the target circuit board is qualified , Otherwise it is judged that the hole position of the target circuit board is unqualified. For example, the hole position detection method of claim 1, after determining that the hole position alignment of the target circuit board is qualified in step S15, it further includes: calculating the first radius of the circle where the first arc is located and the circle where the second arc is located If the ratio of the smaller of the first radius and the second radius to the radius of the complete circle is greater than or equal to the preset ratio threshold, the hole position of the target circuit board is qualified, otherwise The hole position of the target circuit board is unqualified. For example, the hole position detection method of claim 1, after determining that the hole position alignment of the target circuit board is qualified in step S13, it further includes: calculating the radii of the two circles, if the ratio of the smaller radius to the larger radius is greater than If it is equal to the preset ratio threshold, the hole position of the target circuit board is qualified, otherwise the hole position of the target circuit board is unqualified. For example, in the hole position detection method of claim 1, in step S14, at least three points are respectively taken on the first arc and the second arc, and the first arc is determined by the coordinate method or the vertical line method. The second center of the circle where the first center and the second arc are located. As in the hole position detection method of claim 1, the light supplement state in step S11 includes: simultaneously turning on the light source above the target circuit board and the backlight source below the target circuit board. Such as the hole position detection method of claim 1, according to the camera parameters used to obtain the front image of the target circuit board, the size ratio of the front image and the actual target circuit board is obtained, and the first distance is preset according to the size ratio Threshold and second distance The threshold value or the distance data measured on the image is converted into the distance data on the actual circuit board according to the size ratio. A hole position detection method based on up and down drilling circuit boards, used to detect the hole position offset of the target circuit board that has completed the up and down drilling, even if the upper hole or the lower hole is drilled or the upper hole and the lower hole are drilled If the depth is inconsistent, the hole position detection method includes the following steps: S21, in the light supplement state, obtain the front image of the target circuit board; S22, analyze the front image, if the front image includes two If the front image includes a complete circle and two intersecting arcs, then execute S24 and S25; if the front image does not meet the above conditions, then it is determined that the target circuit board is The hole position is unqualified; S23. Calculate the radii of the two circles. If the ratio of the smaller radius to the larger radius is greater than or equal to the preset ratio threshold, determine that the hole depth of the target circuit board is qualified; otherwise, The hole position of the target circuit board is unqualified; S24. Determine the first radius of the circle where the first arc is located and the second radius of the circle where the second arc is located; and S25. If the first radius and the second radius are smaller If the ratio of the radius to the radius of the complete circle is greater than or equal to the preset ratio threshold, it is determined that the hole depth of the target circuit board is qualified, otherwise the hole position of the target circuit board is unqualified. For example, the hole position detection method of claim 7, after determining that the hole depth of the target circuit board is qualified in step S25, it further includes: determining the first center of the circle where the first arc is located and the second circle of the circle where the second arc is located And if the smaller of the distance between the first circle center and the center of the complete circle and the distance between the second circle center and the center of the complete circle is less than or equal to the preset first distance threshold, and The larger distance among them is less than or equal to the preset second distance threshold, wherein if the first distance threshold is less than or equal to the second distance threshold, it is determined that the hole position of the target circuit board is qualified, otherwise it is determined that the hole position of the target circuit board is qualified. The hole position of the target circuit board is unqualified. For example, the hole detection method of claim 7, after determining that the hole depth of the target circuit board is qualified in step S23, the method further includes: calculating the center distance of the two circles in the front image, if the center of the two circles is If the distance is less than or equal to the preset first distance threshold, it is determined that the hole position of the target circuit board is qualified; otherwise, the hole position of the target circuit board is determined to be unqualified. A hole position detection equipment based on upper and lower drilling circuit boards, comprising: a backlight device; a plurality of upper light sources arranged above the backlight device (1); and an image acquisition device; wherein the light emitted by the plurality of upper light sources Convergence is performed on the backlight device, and the image capture device is arranged above the light converging point of the upper light source; wherein the backlight device includes a plurality of independently controlled backlight panels, and each of the backlight panels The backlight source can be turned on or off independently, and a plurality of the backlight boards are spliced and arranged to form a rectangular backlight area of different sizes. The hole position detection device uses the hole position detection described in any one of claim items 1-9 Method to make holes on the circuit board Offset detection.

Images