JP4467966B2 - Substrate visual inspection device - Google Patents

Description

  The present invention relates to a substrate visual inspection apparatus that inspects whether a component mounted state of a substrate (printed substrate) on which an electronic component such as a semiconductor component is mounted is correct.

  The board appearance inspection, which inspects the mounting state of the components mounted on the board, generally obtains an image of the part on the board, and determines whether the mounted part is correct or mounting omission based on this image It is. As for the substrate appearance inspection using such an image, two methods are broadly known. One is a method of determining correctness of a mounted component by collating characters (characters, numbers, symbols, etc.) printed on the component (for example, Patent Document 1 and Patent Document 2), and the other is a component. This is a method for determining whether a mounted component is right or wrong and a mounting omission by pattern matching using a template created for the shape or the like (for example, Patent Document 3 and Patent Document 4). As for the character matching method, a method of recognizing characters using a neural network (for example, Patent Document 1), and the focal length of the camera after measuring the height position by laser light in order to improve the picked-up image of the inspection target component There is known a method for automatically setting (for example, Patent Document 5).

JP 2003-99758 A JP-A-7-175894 JP 2003-110298 A JP-A-8-180191 Japanese Patent Laid-Open No. 11-3415

  As described above, there are a character matching method and a pattern matching method for appearance inspection of a substrate using an image. The character verification method can be applied to parts with characters printed as part types or electrical constants, such as semiconductor packages and resistors. For example, it is possible to perform more accurate inspections on the correctness of mounted parts. And However, since it requires a process of recognizing and collating characters for each part from the part image, the inspection speed is inferior. On the other hand, the pattern matching method is difficult to determine parts with similar shapes, but it is also possible to inspect a plurality of parts at once. In such a case, high-speed inspection is possible. .

  Here, a process from mounting an electronic component on a substrate to appearance inspection will be briefly described. The component is mounted on the board by a component mounting machine. The parts mounting machine is replenished with a certain number of replenishment units. That is, the parts are held on a holding tape, for example, in units of 1000 per tape, and are replenished in units of the holding tape wound in a reel shape. The substrate on which the component is mounted by the component mounting machine is sent to the flow soldering device and subjected to soldering processing by flow soldering, and then sent to the substrate visual inspection device to undergo visual inspection.

  In the appearance inspection in the board appearance inspection apparatus, it is inspected whether (1) a component is mounted at a necessary site or (2) whether the mounted component is correct. The following can be said when considering such inspection contents. First of all, as a general rule, it is not always necessary to inspect whether or not a mounted part is correct. It is not necessary to inspect all parts. This means that it is sufficient to inspect whether or not a component is mounted on a necessary part. When this is related to the characteristics of the character matching method and the pattern matching method, the high-accuracy but slow character matching method is applied only to parts that require checking whether the mounted parts are correct. For other parts, it is effective to inspect whether or not the parts are mounted at the required site by using a high-speed pattern matching method, while maintaining high inspection accuracy and increasing inspection efficiency. I can say that.

  Next, let us consider how to use the standard for properly using the character matching method and the pattern matching method. One specific example is obtained by associating a process from the mounting of the component to the inspection as described above with the inspection content as described above. Whether or not the parts mounted in the necessary parts are correct is determined by the human error when manually refilling the parts mounting machine with the parts mounting system based on the mounting method of the parts by the parts mounting machine. It depends only on whether the parts are refilled. That is, it can be said that there is no mistake in the components mounted on the necessary parts unless there is a mistake that the replacement components are mistaken when the components are supplied. In view of this, it is sufficient to inspect the correctness of a component only when the component is replenished, and only for the component first mounted on the board from that replenishment unit. Inspection is not always necessary. From this, “the component first mounted on the board from the replenishment unit” is derived as a standard for properly using the character matching method and the pattern matching method. Specifically, only the parts that are first mounted on the board from the replenishment unit are applied with a high-accuracy but slow character matching method, and for other parts, whether or not the parts are mounted in the necessary parts. Inspecting by a high-speed pattern matching method is effective for maintaining high inspection accuracy and increasing inspection efficiency.

  The present invention has been made on the basis of the above knowledge, and provides a substrate appearance inspection apparatus that enables highly accurate and highly efficient inspection by properly using the character matching method and the pattern matching method. It is an object.

For the above purpose, in the present invention, each component mounted on a substrate by a component mounting machine is imaged, and whether or not each component is correctly mounted is inspected based on the image obtained by the imaging. In the substrate visual inspection apparatus, a template is prepared in advance for the shape or arrangement state of the component, and includes a character verification inspection system that determines only correctness of the component by comparing only characters printed on the component. A pattern matching inspection system for determining whether the component mounting state is correct or not by pattern matching based on the character matching inspection system and the pattern matching inspection system according to the state of the inspection. When the parts to be replenished are replenished to the component mounting machine in a replenishment unit of a certain quantity, the parts information on the replenishment of parts from the component mounting machine is Therefore, based on this component information, the component first mounted on the substrate from the replenishment unit is inspected by the character verification inspection system, and the other components are inspected by the pattern matching inspection system. It is characterized in that it is used properly.

  Further, in the present invention, for the board appearance inspection apparatus as described above, in the character collation inspection by the character collation inspection system, the character string is created in advance when the character spacing in the character string printed on the component is narrow. Extracting the character string region using a character template to obtain an extracted character string, and separating the characters one by one from the extracted character string based on a preset character width; and the extracted character string Can be used in combination with a process of separating characters based on a histogram obtained by dividing them at equal intervals.

  Further, in the present invention, for the board appearance inspection apparatus as described above, the pattern matching inspection system extracts an edge in the shape of the part in the outer region of the part to be inspected, and obtains the outer size of the part from the extracted edge. By comparing the obtained external size with the size data for the inspection target component, it is possible to perform processing for determining the presence or absence of the necessary component.

In the present invention, it is possible to perform inspection by high-speed pattern matching inspection except when high- precision inspection is required, and it is possible to achieve both high inspection accuracy and inspection with high efficiency. This can be made more effective by setting the standard for proper use of the character matching inspection and the pattern matching inspection at the time of component replenishment in the component mounting machine.

  Hereinafter, preferred embodiments for carrying out the present invention will be described. A configuration of a substrate visual inspection apparatus according to an embodiment of the present invention is shown in FIG. The substrate appearance inspection apparatus 1 includes a character verification inspection system 2, a pattern matching inspection system 3, a control unit 4, and a substrate serial number reading means 5.

  The character collation inspection system 2 includes an imaging unit 6 for character collation inspection and a determination processing unit 7 for character collation inspection. As shown in FIG. 2, the imaging unit 6 has a configuration in which, for example, an imaging unit 21 using a CCD camera or the like is combined with a ring-shaped illumination unit 23. Since the imaging unit 6 is for character verification inspection, the imaging unit 6 captures an image of the substrate 25 with a narrow angle of view, specifically, an angle of view of about one component, and an image such as an image 26 can be acquired. Yes. The determination processing unit 7 determines whether or not various components mounted on the substrate 25 are correct based on an image obtained by the imaging unit 6. The determination is performed by collating the characters printed on the component 28. For this purpose, it has a character collation database 8 that stores collation data such as data related to characters printed on each component.

  The pattern matching inspection system 3 includes an imaging unit 9 for pattern matching inspection and a determination processing unit 10 for pattern matching inspection. As shown in FIG. 2, the imaging unit 9 is basically the same as the imaging unit 6, and has a configuration in which the imaging unit 22 is combined with a ring-shaped illumination unit 24. However, since the imaging unit 9 is used for high-speed pattern matching inspection, the substrate has a wide angle of view, specifically, an angle of view that can capture a plurality of components as in the example of the image 27 in FIG. 25 can be imaged. The determination processing unit 10 performs determination based on correctness of various components mounted on the board 25 and an image obtained by the mounting leakage imaging unit 9. The determination is based on pattern matching based on a template created in advance with respect to the shape and arrangement state of various components. For this purpose, a pattern matching database 11 in which data such as templates are stored is provided.

  The control unit 4 controls the character collation inspection system 2 and the pattern matching inspection system 3. The control includes, for each component, which inspection method of character collation inspection and pattern matching inspection is applied, and in what order the mounted components on the board are inspected. Application of the inspection method requires parts information relating to parts replenishment from the parts mounting machine, as will be described later. For this purpose, the component information receiving unit 12 is provided. Further, it has an inspection list 13 in which the inspection order of components is determined based on the board design information obtained from CAD or the like.

  The board serial number reading means 5 is used to read a serial number given to a board to be inspected. The serial number of the board is attached with a bar code or letters. Therefore, the board serial number reading means 5 is usually configured to read the board serial number by processing an image obtained by imaging them.

  FIG. 3 shows a configuration example of the production line from the component mounting machine to the board appearance inspection apparatus. A substrate 25 on which a component is to be mounted is transported by a transport device 31. When the board 25 reaches the component mounting machine 32, various necessary electronic components are automatically mounted there. The substrate 25 after mounting the components is transported to the flow soldering device 33 by the transporting device 31, and soldering processing is performed. The soldered substrate 25 is conveyed to the substrate appearance inspection apparatus 1 and undergoes appearance inspection.

  The component mounting machine 32 and the board appearance inspection apparatus 1 are connected by a communication line 34, and component information is sent from the component mounting machine 32 to the board appearance inspection apparatus 1. The component information is sent to the board appearance inspection apparatus 1 when the component mounting machine 32 replenishes the component. As described above, replenishment of components in the component mounting machine 32 is performed in units of reel-shaped holding tapes that hold components in units of, for example, 1000 pieces. The reason why the component information is refilled in the component mounting machine 32 is to select an inspection method to be applied based on the component information. In other words, in the present invention, the high-precision inspection efficiency and the high-inspection efficiency are achieved by properly using the character matching inspection that enables high-precision inspection and the pattern matching inspection that enables high-speed inspection according to a predetermined standard. Then, the standard of proper use of the inspection method is set to “parts first mounted on the board from the replenishment unit”, and for this purpose, the inspection method to be applied is selected based on the component information. Therefore, the part information includes the serial number of the board on which the first part of the part in the supplement unit is mounted, the mounting position of the part on the board, and the part type of the part.

  FIG. 4 shows the flow of the main part of the inspection process in the substrate appearance inspection apparatus as described above. First, as processing 101, when a component is replenished by a component mounting machine, the above-described component information regarding the component replenishment is acquired. Next, as processing 102, the serial number of the board to be inspected is read by the board serial number reading means 5 in FIG. In the subsequent process 103, the serial number included in the component information acquired in process 101 is compared with the serial number read in process 102, and it is determined whether or not they match. If they match, the board of that serial number is the board on which the parts are replenished in the component mounting machine and the first part in the replenishment unit is mounted. 1 is obtained from the inspection list 13 in FIG. 1 as to whether or not the part of the type in the part information is a part that can be subjected to character collation inspection. Based on the above, the inspection method is changed to the character verification inspection for the corresponding part on the board (process 104). That is, the inspection is normally performed by the pattern matching inspection, and when the first part in the part replenishment unit becomes the inspection target, the character verification inspection is selected for the part.

  Next, as processing 105, it is determined whether or not the inspection method of the part has priority on inspection accuracy, that is, whether it is a character matching inspection or a pattern matching inspection. If it is a character collation inspection, an image is picked up using the image pickup unit 6 of the character collation inspection system 2 in FIG. 1, and the determination processing unit 7 performs an inspection by character collation (processing 106). On the other hand, if it is a pattern matching inspection, an image is picked up using the image pickup section 9 of the pattern matching inspection system 3 in FIG. 1, and the determination processing section 10 performs an inspection by pattern matching (process 107). Finally, whether the mounting is correct or not is determined as the inspection result of the processing 106 or 107 (processing 108).

  As described above, the character collation inspection and the pattern matching inspection are selectively used based on the “component first mounted on the substrate from the replenishment unit” as a reference, so that an efficient inspection can be performed with high accuracy. For example, when compared with the case of performing a high-accuracy inspection for determining whether a part is correct or not for all parts, an average of N parts can be inspected collectively by a pattern matching inspection for inspecting the presence or absence of a part at a required part. Thus, the inspection speed can be made close to N times, and high inspection accuracy can be maintained.

  Hereinafter, specific contents of the character matching inspection and the pattern matching inspection will be described. First, the character collation inspection using the character collation inspection system 2 in FIG. 1 will be described. In the character collation inspection, characters printed on parts are collated with character data stored for each part in the character collation database 8 in FIG. In the collation, characters are recognized by cutting out characters one by one from an image obtained by imaging the parts on the board. In this case, as shown in FIG. 5A, if the interval between the printed characters on the part is larger than a certain value, it is easy to cut out each character by the histogram shown in the lower part of FIG. On the other hand, as shown in FIG. 5B, when the print characters are in contact with each other and the interval is narrow, it is difficult to cut out with a histogram.

  In such a case, data relating to the number of characters to be recognized and the width of each character is prepared in the character collation database 7 as a character template, for example. Specifically, when the component 42 mounted on the board 41 as shown in FIG. 5 is inspected, the character template 44 corresponding to the character string portion is used, and the character area is extracted from the inspection area 43 by the character area extraction processing. An image (extracted character string) 45 is extracted. Next, a process of dividing and separating characters one by one based on the character region extraction image 45 is performed. In this division / separation process, if the width of each character is not constant, the character is separated by dividing the character with a character width stored in advance as in the divided image 46. On the other hand, when the horizontal width of each character is uniform, the result of the histogram is extracted in the narrow region 47 to be divided and separated at the lowest distribution point. The character recognition image 48 separated for each character is acquired by using these two types of character division separation processing together, and character collation processing is performed based on the character recognition image 48.

  Next, the pattern matching inspection will be described. The pattern matching inspection using the pattern matching inspection system 3 in FIG. 1 is performed based on pattern matching using a template that is created in advance and stored in the pattern matching database 11 with respect to the shape and arrangement state of components. Specifically, as shown in the image of the state of the inspection in FIG. 7, it is determined by pattern matching using the template 56 whether or not the part 51 exists in the inspection region 52, that is, whether or not there is a necessary part. To do. In such a pattern matching inspection, there is no character printing, so that the template 56 corresponding to the component 51 is poor in characteristics, and there is almost no difference between the background substrate 53 and the component 51. Become. That is, even when the component 51 is not mounted, the pattern matching is consistent to some extent, and there is a possibility that a mounting omission is overlooked. In order to prevent this, the following method is applied to parts with poor features. That is, the edge (edge extraction image) 55 of the part shape 54 is extracted from the external region of the part, the external size of the part is obtained from the extracted edge, and the obtained external size is compared with the size data for the inspection target part. To be able to determine the presence or absence of necessary parts.

  In the present invention, the inspection accuracy and the inspection efficiency are made compatible by properly using the character matching inspection that enables high-precision inspection and the pattern matching inspection that enables high-speed inspection. As described above, the present invention is effective in rationalizing the manufacturing process of substrates with higher and higher density, and is particularly useful for the manufacturing process of substrates that are produced in a variety of products in small quantities.

It is a figure which shows the structure of the board | substrate external appearance inspection apparatus by one Embodiment. FIG. 2 is a diagram showing an image of a state of imaging of a substrate by an imaging unit in the substrate appearance inspection apparatus of FIG. 1. It is a figure which shows the structural example of a production line from a component mounting machine to a board | substrate external appearance inspection apparatus. It is a figure which shows the flow of the principal part of the test | inspection process in the board | substrate external appearance inspection apparatus of FIG. It is a figure explaining the cutting method of a character. It is a figure explaining extraction of a character when a character space is narrow. It is the figure which imaged the mode of the pattern matching test | inspection.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Board | substrate appearance inspection apparatus 2 Character matching inspection system 3 Pattern matching inspection system 6, 9 Image pick-up part 25 Board | substrate 28 Component 32 Component mounting machine 44 Character template 45 Character area extraction image (extracted character string)
51 Inspection target component 55 Edge 56 Template

Claims (3)

In the board appearance inspection apparatus configured to inspect each component mounted on a substrate by a component mounting machine and inspect whether or not each of the components is correctly mounted based on the image by the imaging,
A character verification inspection system that determines only correctness of the component by verifying only the characters printed on the component, and pattern matching based on a template that is created in advance regarding the shape or arrangement state of the component. It is equipped with a pattern matching inspection system that determines the correctness of the mounting state of components, and according to the state of inspection, the character matching inspection system and the pattern matching inspection system can be used properly.
When a component to be mounted on the board is replenished to the component mounting machine in a replenishment unit of a certain quantity, component information is received from the component mounting machine regarding the replenishment of the component. The components mounted on the board are inspected by the character verification inspection system, and the other components are inspected by the pattern matching inspection system so as to be used properly. Substrate visual inspection device.   In the character collation inspection by the character collation inspection system, the character string region is extracted using a character template created in advance for the character string when the character interval in the character string printed on the component is narrow. The extracted character string is obtained, and the character is separated from the extracted character string one character at a time based on a predetermined character width, and the histogram is obtained by dividing the extracted character string at equal intervals. The substrate visual inspection apparatus according to claim 1, wherein the substrate visual inspection apparatus can be used in combination with a process for separating the substrate.   The pattern matching inspection system extracts an edge in the shape of the part in the outer region of the part to be inspected, obtains the outer size of the part from the extracted edge, and uses the obtained outer size as size data for the part to be inspected. The board visual inspection apparatus according to claim 1, wherein a process for determining the presence / absence of a necessary part by comparing the parts can be performed.

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