JP2010197252A - Appearance inspection apparatus and appearance inspection method of soldered region - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately determine the quality of a solder fillet formed in an abutting section between printed boards and having a L-shaped inspected region by using a conventional method. <P>SOLUTION: An appearance inspection apparatus includes: a line light source 11 for irradiating the abutting section between the printed boards with a linear light; a camera 12, inclined with respect to a line for connecting the line light source and the abutting section between the printed boards at an angle, and disposed on a bisector having a start point as an intersection between one side and the other side in the L-shaped soldered region as the object to be inspected, and is equiangular to the sides; an image input means; image processing means 212, 213 for processing an image as a section image of a land portion by a light-section method; an inspection parameter extracting means 214 for extracting the inspection parameters, including a shape feature parameter and a location parameter for implementing a soldered region quality inspection based on the section image; a soldered region quality determining means 221 for determining the soldered region quality based on the inspection parameters; and an output means 222 for outputting the determined result. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an appearance inspection apparatus and an appearance inspection method for a soldered part using a line light source.

  Conventionally, the appearance inspection of the soldering part of the printed board, which is generally performed in the past, projects a linear slit light onto the object and detects the light cut image drawn on the surface of the object by this slit light. In addition, a linear light cutting line is extracted from the detected light cutting image. And after removing the noise from this optical cutting line or performing pre-processing to connect the optical cutting line to the partially cut disconnection part, the shape features of this pre-processed optical cutting line The number is counted and compared with a predetermined determination threshold value, and the quality of the shape is determined.

Japanese Patent Publication No. 63-9602

  According to the conventional inspection method, for example, like a soldering portion where the edges of the printed circuit boards are abutted so as to form a substantially L shape in a side view and the lands on the respective printed circuit boards are electrically connected. When the inspection site is substantially L-shaped, the reflected light of the irradiated slit light illuminates the substrate and becomes noise compared to the case where the inspection object is solder placed on a flat substrate. There are many. For this reason, there is a problem that even if a light section line is extracted, the light section line that is desired to be obtained when performing preprocessing cannot be determined, and the shape quality cannot be determined.

  In addition, the surface of the soldering part is mixed with a mirror surface part and a non-mirror surface part, and the irradiated slit light is reflected, and a continuous light cutting line cannot be created, and in a partially cut state A pass / fail judgment must be made. Therefore, a plurality of parameters necessary for the determination are prepared, and there is a problem that the processing becomes complicated and complicated. This has become remarkable with the recent lead-free solder.

  An object of the present invention is to provide a soldering portion (solder fillet) formed at a butting portion of a printed circuit board and having a substantially L-shaped inspection region that electrically connects the lands of the abutting portion of each printed circuit board. ) Is accurately determined by a simple method.

In order to solve the above-described problem, an appearance inspection apparatus for a soldering part according to claim 1 of the present invention provides:
An appearance inspection apparatus for a soldering part that performs an appearance inspection of a substantially L-shaped soldering part that is formed in abutting portions where the printed boards are abutted to each other and electrically connects the lands of each printed circuit board,
It is arranged on a bisector that is equiangular with each side starting from the intersection of one side and the other side of the substantially L-shaped soldering site to be inspected, and is linear toward the abutting part between the printed circuit boards. A line light source that emits light;
Each side having an angle with respect to a straight line connecting the line light source and the abutting portion between the printed circuit boards, and starting from the intersection of one side and the other side of the substantially L-shaped soldering portion to be inspected And a camera for photographing the soldering part from an angle different from the angle at which the line light source illuminates the soldering part,
An image input means for capturing a land portion to be inspected by the camera when the line light source is illuminated, and inputting the captured image;
Image processing means for processing the input image as a cut image to be inspected by a light cutting method;
Based on the cut image that has been subjected to the image processing, inspection parameter extraction means for extracting an inspection parameter composed of a shape feature parameter and a position parameter for performing a soldering site quality inspection;
Based on the extracted inspection parameters, a soldering part pass / fail judgment means for judging soldering part pass / fail,
Output means for outputting the result of the determination.

Moreover, the visual inspection method of the soldering part according to claim 5 of the present invention is:
A method for inspecting the appearance of a substantially L-shaped soldering part that is formed in abutting portions where the printed circuit boards are abutted to each other and electrically connects the lands of each printed circuit board,
It is arranged on a bisector that is equiangular with each side starting from the intersection of one side and the other side of the substantially L-shaped soldering site to be inspected, and is linear toward the abutting part between the printed circuit boards. A line light source that emits light;
Each side having an angle with respect to a straight line connecting the line light source and the abutting portion between the printed circuit boards, and starting from the intersection of one side and the other side of the substantially L-shaped soldering portion to be inspected And a camera for photographing the soldering part from an angle different from the angle at which the line light source illuminates the soldering part,
Shoot the land part to be inspected with the camera at the time of illumination of the line light source, input the captured image,
The input image is subjected to image processing as a cut image to be inspected by a light cutting method,
Based on the cut image that has been subjected to the image processing, to extract inspection parameters consisting of shape feature parameters and position parameters to perform soldering site quality inspection,
Based on the extracted inspection parameters, determine whether the soldering site is good,
The determination result is output.

  According to the appearance inspection apparatus for a soldering part according to claim 1 of the present invention and the appearance inspection method for a soldering part according to claim 5, it is difficult to perform an appearance inspection of a substantially L-shaped soldering part. Thus, without preparing a large number of determination parameters, the appearance inspection of the substantially L-shaped soldering portion to be inspected can be performed easily and accurately.

Further, an appearance inspection apparatus for a soldering part according to claim 2 of the present invention is the appearance inspection apparatus for a soldering part according to claim 1,
The inspection parameter extracting means includes two reference lines after image processing and these two reference lines from two light cutting lines obtained by a light cutting method by the line light source illuminating each printed circuit board. The intersection of the reference line intersects and calculates the actual three-dimensional height of the solder area as a positional parameter for determining the solder quality based on the reference line intersection and the cut image of the land portion obtained by the light cutting method. In addition, a shape feature parameter for determining whether the solder is good or bad is extracted from the cut image of the land portion indicating the solder area, the reference line intersection, and the reference line.

Moreover, the visual inspection method of the soldering part according to claim 6 of the present invention is the visual inspection method of the soldering part according to claim 5,
The inspection parameter extraction means obtains a reference line intersection from two light cutting lines obtained by the light cutting method when the line light source irradiates each printed circuit board, and is obtained by the reference line intersection and the light cutting method. Based on the cut image of the land portion, the three-dimensional actual height of the solder area as a positional parameter for determining solder quality is calculated, and the shape feature, position, It is characterized in that a solder quality determination parameter is extracted from the reference line intersection.

  According to the appearance inspection apparatus for a soldering part according to claim 2 and the soldering part appearance inspection method according to claim 6 of the present invention, soldering can be performed without performing preprocessing such as noise processing or connection processing for partial disconnection. The appearance inspection of the attachment site can be performed with high accuracy.

Further, an appearance inspection apparatus for a soldering part according to claim 3 of the present invention is provided.
It is an appearance inspection device for a soldering part that performs an appearance inspection for the presence or absence of a bridge between substantially L-shaped soldering parts that are formed in abutting portions where the printed circuit boards are brought into contact with each other and electrically connect the lands of the printed circuit boards. And
A line that is arranged on a bisector that is equiangular with each side starting from the intersection of one side and the other side of the substantially L-shaped soldering site to be inspected, and irradiates toward the abutting portion of the printed circuit boards Line light source,
Each side having an angle with respect to a straight line connecting the line light source and the abutting portion between the printed circuit boards, and starting from the intersection of one side and the other side of the substantially L-shaped soldering portion to be inspected And a camera for photographing the soldering part from an angle different from the angle at which the line light source illuminates the soldering part,
Image input means for capturing images between adjacent lands that are irradiated by the line light source and to be inspected by the camera with the camera, and for inputting the captured image;
Image processing means for processing the input image as a cut image to be inspected by a light cutting method;
Based on the cut image that has been subjected to the image processing, inspection parameter extraction means for extracting inspection parameters for performing a pass / fail inspection between soldered sites;
Based on the extracted inspection parameters, the quality determination means between the soldering sites for determining the quality between the soldering sites,
Output means for outputting the result of the determination.

In addition, the method for inspecting the appearance of a soldering part according to claim 7 of the present invention includes:
A soldering part appearance inspection method for performing an appearance inspection for the presence or absence of a bridge between substantially L-shaped soldering parts that are formed in abutting portions where the printed circuit boards are brought into contact with each other and electrically connect the lands of each printed circuit board. There,
Arranged on a bisector that is equiangular with each side starting from the intersection of one side and the other side that form a substantially L-shaped soldering site to be inspected, and linear toward the abutting portion between the printed boards A line light source that emits
Each side having an angle with respect to a straight line connecting the line light source and the abutting portion between the printed circuit boards, and starting from the intersection of one side and the other side of the substantially L-shaped soldering portion to be inspected And a camera for photographing the soldering part from an angle different from the angle at which the line light source illuminates the soldering part,
Shoot between adjacent lands to be inspected with the camera when the line light source is illuminated, and input the captured image,
The input image is subjected to image processing as a cut image to be inspected by a light cutting method,
Based on the cut image that has been subjected to the image processing, to extract the inspection parameters of the quality between the solder lands,
Based on the extracted inspection parameters, determine the quality between solder lands,
The determination result is output.

  According to the soldering part appearance inspection apparatus according to claim 3 of the present invention and the soldering part appearance inspection method according to claim 7, when the presence or absence of a bridge between the substantially L-shaped soldering parts is inspected. In addition, it is possible to easily and accurately perform an appearance inspection for the presence or absence of a bridge between the substantially L-shaped soldering parts to be inspected without preparing complicated and many determination parameters.

Further, an appearance inspection apparatus for a soldering part according to claim 4 of the present invention is the appearance inspection apparatus for a soldering part according to claim 3,
The inspection parameter extracting means includes two reference lines after image processing and these two reference lines from two light cutting lines obtained by a light cutting method by the line light source illuminating each printed circuit board. Is obtained, and a parameter for determining whether or not there is a bridge between the lands is extracted from each of the reference line intersection and two reference lines.

Further, an appearance inspection method for a soldering part according to claim 8 of the present invention is the method for visual inspection of a soldering part according to claim 7,
The inspection parameter extracting means includes two reference lines after image processing and these two reference lines from two light cutting lines obtained by a light cutting method by the line light source illuminating each printed circuit board. A reference line intersection point is obtained, and a distance as a parameter for determining whether or not there is a bridge between lands is extracted from each of the reference line intersection point and two reference lines.

  According to the soldering part appearance inspection apparatus according to the fourth aspect of the present invention and the soldering part appearance inspection method according to the eighth aspect of the present invention, without performing preprocessing such as noise processing or connection processing for partial disconnection. In addition, it is possible to accurately perform the appearance inspection of the soldering parts and the appearance inspection of the presence or absence of a bridge between the soldering parts.

  According to the present invention, it is possible to accurately determine the quality of a solder fillet formed at the abutting portion of a printed circuit board and having a substantially L-shaped inspection site that electrically connects the lands of each printed circuit board with a simple method. Can be done well.

It is a schematic perspective view which shows the non-defective product and the defective product of the substantially L-shaped solder part to which the appearance inspection device and the appearance inspection method of the soldering part according to one embodiment of the present invention are applied in various forms. It is a block diagram which shows schematic structure of the external appearance inspection apparatus of the soldering site | part which concerns on one Embodiment of this invention. In FIG. 1, it is a perspective view which shows the state which installed the line light source and the camera. It is a front view which shows the printed circuit board which mutually faced in FIG. 3 with a line light source, a camera, etc. FIG. It is a side view which shows the printed circuit board which faced each other in FIG. 3 with a line light source, a camera, etc. It is a schematic flowchart which shows the external appearance inspection method using the external appearance inspection apparatus of the soldering site | part shown in FIG. FIG. 3 is an image processing display example showing a good solder part (G) in FIG. 1 using a light cutting method. FIG. FIG. 2 is an example of image processing display showing a solder-excess solder part (F-1) which is a first aspect of the defective product in FIG. 1 using a light cutting method. It is an example of image processing display which shows the unsoldered solder part (F-2) which is the 2nd aspect of the inferior goods in FIG. 1 using the optical cutting method. It is an example of image processing display which shows the unjoined solder part (F-3) when there is solder only on one side of the printed circuit board which is the third mode of the defective product in FIG. It is a table | surface which shows the parameter, conditions, and logic formula explaining a solder land part non-defective product determination logic. Schematic showing non-defective product (without bridge) and defective product (with bridge) between lands formed with substantially L-shaped solder portions to which an appearance inspection device and an appearance inspection method for a soldering site according to an embodiment of the present invention are applied. It is a perspective view. It is a perspective view which shows the state which installed the line light source and the camera in FIG. FIG. 13 is an example of image processing display showing the inter-land good product (LG) shown in FIG. 12 using a light cutting method. FIG. FIG. 13 is an image processing display example showing the inter-land defective product (LB) shown in FIG. 12 using a light cutting method. FIG. It is a table | surface which shows the parameter, conditions, and logical formula explaining the non-defective product determination logic between solder lands.

  Hereinafter, an appearance inspection apparatus and an appearance inspection method for a soldered part according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic perspective view showing various types of non-defective products and defective products of a substantially L-shaped solder portion to which an appearance inspection apparatus and an appearance inspection method for a soldering part according to an embodiment of the present invention are applied. FIG. 2 is a block diagram showing a schematic configuration of an appearance inspection apparatus for a soldered part according to an embodiment of the present invention. FIG. 3 is a perspective view showing a state in which the line light source and the camera are installed in FIG. FIG. 4 is a front view showing the printed circuit boards abutted against each other in FIG. 3 together with a line light source and a camera. FIG. 5 is a side view showing the printed circuit boards abutted against each other in FIG. 3 together with a line light source and a camera.

  In FIG. 1, soldering portions that electrically connect the lands on each edge in a state where the edges of the printed circuit boards abut each other so as to form a substantially L shape in a side view, that is, a substantially L-shaped solder. Thus, inspection parts where good and defective products are mixed are formed at predetermined intervals along the abutting portions of the printed circuit boards 51 and 52. In this case, a non-defective solder part (G) is arranged on the leftmost side along the abutting part of the printed circuit boards 51 and 52, and a defective solder part (F) having three different modes is arranged on the right side. Show.

  For example, when the product is a photoelectric switch, one printed circuit board is an electronic component mounting board and the other printed circuit board is an LED display element mounting board. Then, in order to electrically connect each of the electronic components and electrical components mounted on each printed circuit board, land portions that are partially in contact with each other at the abutting portions of the edge portions of the respective printed circuit boards are formed. Solder is fixed to the printed circuit board to achieve electrical continuity between the two printed circuit boards.

  The solder part (F) of the defective product in FIG. 1 includes the solder-excessive solder part (F-1) which is the first aspect of the defective product and the unsoldered solder part (F) which is the second aspect of the defective product. -2) and an unjoined solder portion (F-3) in the case where solder is present only on one side of the substrate which is the third mode of the defective product. The unsoldered solder part (F-2) has a spare solder only on the printed circuit board 51 side, and the unbonded solder part (F-3) is soldered between the printed circuit board 51 and the printed circuit board 52. It is not joined.

  As shown in FIGS. 2 to 4, the soldering site appearance inspection apparatus 1 is an apparatus for inspecting the appearance of the above-described substantially L-shaped soldering portion to be inspected. A camera 12 for photographing a target part, an image processing device 21 for inputting an image from the camera 12 and image processing, and an inspection device 22 for determining whether the inspection part is soldered according to inspection parameters and displaying a determination result. Yes.

  In FIG. 2, the image processing device 21 and the inspection device 22 are shown as one body, but they may be separate.

  The line light source 11 is arranged perpendicularly to a substantially center position of a substantially L-shaped soldering portion that is an inspection object, and the camera 12 is photographed obliquely. The arrangement relationship among the line light source 11, the camera 12, and the substantially L-shaped soldering portion is clarified based on FIGS. 3 to 5. More specifically, as shown in FIGS. 3 and 4, the line light source 11 is equiangular with each side starting from the intersection of one side and the other side forming the substantially L-shaped soldering site to be inspected. Arranged on a bisector. The line light source 11 irradiates linear slit light between the printed boards 51 and 52 and the soldering site or between the soldering sites. The slit light is irradiated perpendicularly to each of the printed circuit boards 51 and 52, and the line light is irradiated so as to be substantially perpendicular to the substantially L shape.

  Further, the camera 12 is composed of a CCD camera, for example, and has an angle with respect to a straight line connecting the line light source and the abutting portions of the printed circuit boards 51 and 52 as shown in FIG. It is arranged on a bisector that is equiangular with each side starting from the intersection of one side and the other side of the L-shaped soldering site, and the soldering site is photographed obliquely. More specifically, the camera 12 images the soldering site from an angle different from the angle at which the line light source 11 illuminates the soldering site.

  In the present embodiment, the angle formed by the extension line from the abutting part 50 between the printed circuit boards 51 and 52 to the line light source 11 and the extension line from the abutting part 50 between the printed circuit boards 51 and 52 to the camera 12 is as follows. The angle is about 30 degrees when viewed from the line light source 11 side (see FIG. 5). Further, the line light source 11 and the camera 12 are movable in parallel along the abutting portion between the printed circuit boards 51 and 52, and each soldering irradiated with linear slit light by the line light source 11 while moving is performed. Each part and the adjacent soldering part are imaged. The above-described angle is an example suitable for the present invention, and the angle is not limited to this specific value.

  The image input unit 211 captures the inspection object with the camera 12 in the state of irradiating the slit light, and inputs the captured image.

  Then, for example, the line light source 11 and the camera 12 are attached to the tip of the arm of the robot and moved parallel from one end of the printed circuit boards 51 and 52 toward the other end, and the soldered part to be inspected (see FIG. ) And between adjacent soldering parts (see FIG. 12) are sequentially photographed, an inspection image is acquired by the image processing device 21 through the image input means 211, and the pass / fail of the appearance inspection result is determined by the inspection device 22. Yes.

  As shown in FIG. 2, the image processing apparatus 21 and the inspection apparatus 22 include, in addition to the image input means 211 described above, a solder land portion image processing means 212, an inter-land land image processing means 213, and a pass / fail judgment parameter extraction means 214. And a pass / fail judgment means 221 and a judgment result output means 222, which extract a solder land section cut image and a solder land cut image based on the photographed images (FIGS. 7 to 10, FIG. 14 and FIG. 15). reference). Then, based on the acquired image, inspection parameters are extracted in order to perform a visual inspection pass / fail judgment, and a visual inspection pass / fail is determined based on the inspection parameters.

  Here, the solder land portion image processing means 212 is a means for subjecting the solder land portion image input by the image input means to image processing by a known light cutting method. The solder land image processing unit 213 is a unit that performs image processing on the image between the solder lands input by the image input unit by a light cutting method. Further, the quality determination parameter extraction unit 214 extracts parameters for determining the quality of the soldered part (quality of the solder land portion) from the processing image, and the parameter for determining the quality between the soldered parts (bridge presence / absence). Is extracted from the processed image. The pass / fail judgment means 221 is a means for judging pass / fail of a soldered part (solder land part pass / fail) and pass / fail between soldered parts (bridge presence / absence) based on the parameters extracted by the pass / fail judgment parameter extracting means. is there. This is because the determination result output means 222 is a means for outputting the quality of the soldered part (the quality of the solder land portion) determined by the quality determination means 221 and the quality between the soldered parts (the presence or absence of a bridge).

  Hereinafter, a basic flow of an appearance inspection method using an appearance inspection apparatus for a soldered part according to an embodiment of the present invention will be described based on a flowchart of FIG.

  First, it is determined whether or not there is a substantially L-shaped solder image input (step S11). If there is no substantially L-shaped solder image input, this routine is repeated until this solder image is input. If it is determined in step S11 that a substantially L-shaped solder image is input, the subsequent processing is branched depending on either the solder land portion or between the solder lands (step S12). As an example of the determination method at that time, it is possible to determine from the teaching position of the robot registered in advance. After that, if it is a solder land portion, the cut image processing of the solder land portion is performed (step S13). The solder land cut image processing uses a known technique introduced in the prior art.

  7 to 10 show the contents of image processing obtained by this cut image processing. Here, on the actual image processing screen, only the reference lines 51a and 52a, the reference line intersection 50a, and the solder areas g and f are displayed brightly and the others are darkened. As shown. The same applies to FIGS. 14 and 15 showing other image processing contents.

  The reference line 1 in FIG. 7 is obtained by capturing the reflected light of the light irradiated on the printed circuit board 51 with the camera 12 and displaying it on the image processing screen as the reference line 51a by the light cutting method. The reflected light of the light irradiated onto the printed circuit board 52 is imaged by a camera and displayed on the image processing screen as a reference line 52a by a light cutting method. The reference line intersection 50 a corresponds to the position of the abutting portion between the printed circuit board 51 and the printed circuit board 52. The reason why the reference line 51a and the reference line 52a do not form a right angle is because the direction in which the camera 12 images the soldering part is oblique with respect to the direction in which the line light source 11 irradiates the soldering part. is there.

  Here, FIG. 7 is an image processing display example in which the good solder portion (G) in FIG. 1 is shown using a light cutting method. Further, FIG. 8 is an example of image processing display showing the excessive solder portion (F-1) which is the first mode of the defective product in FIG. 1 by using the optical cutting method. FIG. 9 is an example of image processing display showing the unsoldered solder portion (F-2) which is the second mode of the defective product in FIG. 1 by using the optical cutting method. Further, FIG. 10 shows image processing using an optical cutting method to show an unjoined solder portion (F-3) when there is solder only on one side of the printed circuit board which is the third mode of the defective product in FIG. It is a display example.

  Next, inspection parameters (H, L1 / L2, α) are extracted (step S14). The specific contents of the inspection parameter will be described later in detail.

  Next, a quality determination (a quality determination of the soldering part) is performed based on the extracted inspection parameters (step S15). The specific contents of the pass / fail judgment based on the inspection parameters will be described later.

  On the other hand, in the routine of FIG. 6, if there is no solder land portion in step S12, a cut image process between the solder lands is performed (step S16). The image processing between the solder lands uses a known technique introduced in the prior art. Here, FIG. 14 is an image processing display example showing the inter-land non-defective product (LG) shown in FIG. 12 by using the light cutting method. FIG. 15 is an example of image processing display showing the inter-land defective product (LB) shown in FIG. 12 by using a light cutting method.

  Next, the inspection parameters (LL1, LL2) are extracted (step S17). The specific contents of the inspection parameter will be described later in detail.

  Next, a pass / fail judgment (determination of the presence or absence of a bridge between soldering parts) is performed based on the extracted inspection parameters (step S18). The specific contents of the pass / fail judgment based on the inspection parameters will be described later.

  Finally, the pass / fail judgment results obtained in steps S15 and S18 are output (step 16).

  Next, the inspection parameter extraction method in step S14 and step S17 that constitutes a component unique to the present invention will be described. First, the parameter extraction method relating to the appearance inspection of the soldered part, which is Step S14, will be described. Here, the two reference lines 51a and 52a and the reference line intersection 50a are the basis for obtaining the position parameter. Also, the solder regions g and f displayed after image processing are the basis for obtaining the shape feature parameters.

  First, as shown in FIGS. 7 and 8, parameters for confirming the presence or absence of solder are obtained. For this parameter, a value corresponding to the three-dimensional height data of the actual solder region is calculated as a position parameter by the optical cutting method. In this calculation, the distance from the intersection of the reference points obtained by the light cutting method to the solder area is obtained, and the height H is set as shown in FIG.

  In obtaining the height H, taking FIG. 8 as an example, the center of gravity Gv1 of the solder region f is obtained, and the horizontal distance between the center of gravity Gv1 and the reference line intersection 50a corresponds to the actual height of the soldering portion. The height H is calculated.

  Next, a shape characteristic parameter for confirming pattern peeling due to unsoldering, that is, for example, a case where spare solder is present only on one printed circuit board is obtained. In obtaining this parameter, a vertical line on the screen is extended from both ends of the solder region f-2 on the image processing screen in FIG. 9 to the reference lines 51a and 52a, and then the intersection is obtained. At this time, each end in the longitudinal direction of the solder region is obtained, and a vertical line is extended upward from the upper end to make it an intersection with the upper reference line 51a, and downward from the upper and lower ends of the screen. The perpendicular is extended to be an intersection with the lower reference line 52a. Then, the distances between these intersections and the reference line intersection 50a are set as L1 and L2, respectively, and the ratio L1 / L2 of these distances is calculated. As is clear from FIG. 9, the L1 / L2 ratio is considerably different from 1 in a state where solder is present only on one printed circuit board land.

  Next, a shape feature parameter for confirming pattern peeling due to unbonded solder is obtained. This parameter is obtained by obtaining the center of gravity Gv2 of the solder region f-3 on the image processing screen of FIG. 10, obtaining the angles α1 and α2 between the straight line connecting the center of gravity Gv2 and the reference intersection, and the respective reference lines. The ratio is calculated and set as α. Specifically, as shown in FIG. 10, an angle formed between this straight line and the reference line 51a obtained from one substrate 51 is α1, and the straight line and the reference line 52a obtained from the other substrate 52 are If the angle formed is α2, α = α1 / α2. As is apparent from FIG. 10, in the solder unbonded state, the magnitude relationship between α1 and α2 is different, and α (= α1 / α2) is considerably different from 1.

  Next, in step S15 of the routine of FIG. 6, that is, the value of each parameter described above is compared with the value (threshold value) of the acceptance criterion parameter set in advance to determine whether or not to solder. Here, FIG. 11 is a list showing parameters, conditions, and logical expressions for explaining the solder land portion non-defective product determination logic.

  Here, the solder land portion non-defective product determination logic will be described. At this time, the logical product of the following three element conditions is calculated (see FIG. 11). When the height H is within a predetermined range, the ratio L1 / L2 of the length to the reference intersection is within the predetermined range, and the angle ratio α to the reference line is within the predetermined range The solder land portion is determined to be a non-defective product (refer to the non-defective product (G) in FIG. 3), and if any one of these three conditions is not satisfied, it is determined to be a defective solder product (defective product (F-1) in FIG. 3). To (F-3)).

  Next, step S17 of the routine shown in FIG. 6, that is, a parameter extraction method for determining whether or not there is a bridge between the soldering portions will be described in detail.

  Here, FIG. 12 shows a non-defective product (no bridge) between the lands formed with substantially L-shaped solder portions to which the visual inspection apparatus and visual inspection method for a soldering part according to an embodiment of the present invention are applied. It is a schematic perspective view which shows (with a bridge). FIG. 13 is a perspective view showing a state in which the line light source and the camera are installed in FIG. At this time, if no bridge is generated between the soldering parts (between lands), the reference line 51a and the reference line 52a are displayed without interruption as shown in the image processing screen of FIG. On the other hand, when a bridge is generated between the soldering parts (between lands), as shown in the image processing screen of FIG. 15, a part of the reference lines 51a and 52a becomes discontinuous. Then, on the image-processed screen, the distance between the reference line intersection 50a and the point closest to the reference line intersection 50a at the point where the continuous reference lines 51a and 52a on each reference line become discontinuous, Let LL1 and LL2.

  Next, step S18 of the routine of FIG. 6, that is, the pass / fail judgment of the solder lands is performed by comparing the value of each parameter described above with the value (threshold value) of the acceptance criterion parameter set in advance.

  FIG. 16 is a list showing parameters, conditions, and logical expressions for explaining the solder land inter-defect determination logic. Here, the inter-land non-defective product determination logic will be described. At this time, the logical product of the following two element conditions is calculated (see FIG. 16).

  When the distance LL1 as one parameter is equal to or less than the maximum distance and the distance LL2 as the other parameter is equal to or less than the maximum distance, it is determined as a non-defective product ((LG) in FIG. 12). If any one of them is not satisfied, it is determined that the solder is defective (refer to a defective product (LB) in FIG. 12).

  Then, it is obtained based on the non-defective product determination result of each substantially L-shaped solder portion obtained based on the solder land portion good product determination logic which is step S15 of the routine of FIG. 6 and the inter-land good product determination logic which is step S18. The presence / absence of a bridge between adjacent lands (non-defective product determination result) is displayed through the determination result output means.

  For inspection objects that are judged to be non-defective items between each soldering part and each soldering part, all the soldering parts are non-defective and no bridges are formed between the soldering parts. To do. On the other hand, if there is at least one defective product between any of the soldering parts or between the soldering parts, the inspection is rejected.

  As described above, according to the present invention, for the inspection of the substantially L-shaped soldered portion, the pre-processing such as noise removal or optical cutting line connection processing is performed by extracting the inspection parameters based on the obtained image. The inspection parameters are set by using the three-dimensional information by the light cutting method based on the input image, the feature amount by the substantially L-shaped shape to be inspected, and the light cutting line that has been partially cut. Since the pass / fail judgment is made based on this, it becomes possible to easily and accurately inspect the substantially L-shaped soldered portion.

  Therefore, as a prior art of solder fillet shape inspection using a line light source for the appearance inspection of a substantially L-shaped soldering portion that performs soldering by abutting the land portions of two printed circuit boards in a substantially L-shape All the problems in the case of applying the technology as described in Japanese Patent Application No. 63-9602 have been solved.

  Specifically, since the inspection site is substantially L-shaped, the light cut line of the solder fillet that the reflected light of the irradiated line light source illuminates the substrate etc. and becomes a noise component compared to a flat printed board And a high-intensity detection part of noise reflected from a solder fillet part or a land on the substrate are not mixed, and it is no longer possible to determine the desired light section line. Therefore, the problem that the pass / fail judgment cannot be made because the area formed by the light cutting line is not sufficient as the judgment parameter.

  In addition, there is a part where the irradiated line light source is totally reflected due to the presence of mirror surface parts and non-mirror surface parts in the surface state of the soldered part, which has become prominent in recent lead-free soldering. In other words, the connection process of the optical cutting line between the optical cutting line on the two substrates obtained from the feature of the substantially L-shape and the optical cutting line partially cut of the solder fillet portion is obtained. There is no need to perform this, and by using the determination parameter obtained from the partially cut optical cutting line, it is possible to accurately determine the quality of the substantially L-shaped solder part and the presence or absence of a bridge between these solder parts. It was.

  In the above-described embodiment, two printed circuit boards are abutted in an L shape in a side view, and an appearance inspection of a substantially L-shaped solder portion of the abutting portion is performed. However, the present invention is not limited to such a range, for example, a so-called T-shaped abutting form in which the edge of the other printed circuit board is abutted in the middle of the substrate surface of one printed circuit board. Also, it is applicable if the soldering part for electrically connecting the printed boards is substantially L-shaped.

  In addition, the abutting angle between the printed circuit boards is not a right angle in a strict sense, but the present invention can be applied if the soldering portions are substantially L-shaped by abutting at a certain angle to each other. Needless to say.

  Needless to say, even if there is a conductive foreign substance that short-circuits between adjacent soldering sites, the presence can be detected in the same manner as the bridge described above.

DESCRIPTION OF SYMBOLS 1 Appearance inspection apparatus of soldering part 11 Line light source 12 Camera 21 Image processing apparatus 22 Inspection apparatus 50 Abutting part 50a Reference line intersection 51 Printed circuit board 51a Reference line 52 Printed circuit board 52a Reference line 211 Image input means 212 Solder land part image processing Means 213 Image processing means between solder lands 214 Quality determination parameter extraction means 221 Quality determination means 222 Determination result output means

Claims (8)

An appearance inspection apparatus for a soldering part that performs an appearance inspection of a substantially L-shaped soldering part that is formed in abutting portions where the printed boards are abutted to each other and electrically connects the lands of each printed circuit board,
It is arranged on a bisector that is equiangular with each side starting from the intersection of one side and the other side of the substantially L-shaped soldering site to be inspected, and is linear toward the abutting part between the printed circuit boards. A line light source that emits light;
Each side having an angle with respect to a straight line connecting the line light source and the abutting portion between the printed circuit boards, and starting from the intersection of one side and the other side of the substantially L-shaped soldering portion to be inspected And a camera for photographing the soldering part from an angle different from the angle at which the line light source illuminates the soldering part,
An image input means for capturing a land portion to be inspected by the camera when the line light source is illuminated, and inputting the captured image;
Image processing means for processing the input image as a cut image to be inspected by a light cutting method;
Based on the cut image that has been subjected to the image processing, inspection parameter extraction means for extracting an inspection parameter composed of a shape feature parameter and a position parameter for performing a soldering site quality inspection;
Based on the extracted inspection parameters, a soldering part pass / fail judgment means for judging soldering part pass / fail,
An appearance inspection apparatus for a soldering part, comprising: an output unit that outputs the determined result.   The inspection parameter extracting means includes two reference lines after image processing and these two reference lines from two light cutting lines obtained by a light cutting method by the line light source illuminating each printed circuit board. The intersection of the reference line intersects and calculates the actual three-dimensional height of the solder area as a positional parameter for determining the solder quality based on the reference line intersection and the cut image of the land portion obtained by the light cutting method. And a shape feature parameter for determining whether the solder is good or bad is extracted from the cut image of the land portion indicating the solder area, the reference line intersection, and the reference line. Visual inspection equipment. It is an appearance inspection device for a soldering part that performs an appearance inspection for the presence or absence of a bridge between substantially L-shaped soldering parts that are formed in abutting portions where the printed circuit boards are brought into contact with each other and electrically connect the lands of the printed circuit boards. And
It is arranged on a bisector that is equiangular with each side starting from the intersection of one side and the other side of the substantially L-shaped soldering site to be inspected, and is linear toward the abutting part between the printed circuit boards. A line light source that emits light;
Each side having an angle with respect to a straight line connecting the line light source and the abutting portion between the printed circuit boards, and starting from the intersection of one side and the other side of the substantially L-shaped soldering portion to be inspected And a camera for photographing the soldering part from an angle different from the angle at which the line light source illuminates the soldering part,
An image input unit that captures an image between adjacent lands to be inspected at the time of illumination of the line light source with the camera, and inputs the captured image;
Image processing means for processing the input image as a cut image to be inspected by a light cutting method;
Based on the cut image that has been subjected to the image processing, inspection parameter extraction means for extracting inspection parameters for performing a pass / fail inspection between soldered sites;
Based on the extracted inspection parameters, the quality determination means between the soldering sites for determining the quality between the soldering sites,
An appearance inspection apparatus for a soldering part, comprising: an output unit that outputs the determined result.   The inspection parameter extracting means includes two reference lines after image processing and these two reference lines from two light cutting lines obtained by a light cutting method by the line light source illuminating each printed circuit board. A cross-reference line intersection is obtained, and a parameter for determining whether or not there is a bridge between the lands is extracted from each of the reference line intersection and two reference lines. Appearance inspection device. A method for inspecting the appearance of a substantially L-shaped soldering part that is formed in abutting portions where the printed circuit boards are abutted to each other and electrically connects the lands of each printed circuit board,
It is arranged on a bisector that is equiangular with each side starting from the intersection of one side and the other side of the substantially L-shaped soldering site to be inspected, and is linear toward the abutting part between the printed circuit boards. A line light source that emits light;
Each side having an angle with respect to a straight line connecting the line light source and the abutting portion between the printed circuit boards, and starting from the intersection of one side and the other side of the substantially L-shaped soldering portion to be inspected And a camera for photographing the soldering part from an angle different from the angle at which the line light source illuminates the soldering part,
Shoot the land part to be inspected with the camera at the time of illumination of the line light source, input the captured image,
The input image is subjected to image processing as a cut image to be inspected by a light cutting method,
Based on the cut image that has been subjected to the image processing, to extract inspection parameters consisting of shape feature parameters and position parameters to perform soldering site quality inspection,
Based on the extracted inspection parameters, determine whether the soldering site is good,
A method for inspecting the appearance of a soldering site, wherein the result of the determination is output.   The inspection parameter extraction means obtains a reference line intersection from two light cutting lines obtained by a light cutting method when the line light source illuminates each printed circuit board, and is obtained by the reference line intersection and the light cutting method. Based on the cut image of the land portion, the three-dimensional actual height of the solder area as a positional parameter for determining solder quality is calculated, and the shape feature, position, 6. The method for inspecting the appearance of a soldering part according to claim 5, wherein a parameter for determining whether the solder is good or bad is extracted from the intersection of the reference lines. A soldering part appearance inspection method for performing an appearance inspection for the presence or absence of a bridge between substantially L-shaped soldering parts that are formed in abutting portions where the printed circuit boards are brought into contact with each other and electrically connect the lands of each printed circuit board. There,
Arranged on a bisector that is equiangular with each side starting from the intersection of one side and the other side that form a substantially L-shaped soldering site to be inspected, and linear toward the abutting portion between the printed boards A line light source that emits
Each side having an angle with respect to a straight line connecting the line light source and the abutting portion between the printed circuit boards, and starting from the intersection of one side and the other side of the substantially L-shaped soldering portion to be inspected And a camera for photographing the soldering part from an angle different from the angle at which the line light source illuminates the soldering part,
Shoot between adjacent lands to be inspected with the camera when the line light source is illuminated, and input the captured image,
The input image is subjected to image processing as a cut image to be inspected by a light cutting method,
Based on the cut image that has been subjected to the image processing, to extract the inspection parameters of the quality between the solder lands,
Based on the extracted inspection parameters, determine the quality between solder lands,
A method for inspecting the appearance of a soldering site, wherein the result of the determination is output. The inspection parameter extracting means includes two reference lines after image processing and these two reference lines from two light cutting lines obtained by a light cutting method by the line light source illuminating each printed circuit board. 8. A soldering part according to claim 7, wherein a reference line intersection at which the crossing points are obtained, and a distance as a parameter for determining whether or not there is a bridge between lands is extracted from each of the reference line intersection and the two reference lines. Visual inspection method.

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