Inspection system

Abstract

The first inspection device 3 of the inspection system 1 includes a conveying mechanism, a first platform, a first imaging unit, and a first inspection unit 301, and performs automatic inspection. This automatic inspection includes: conveying an object to the first platform via the conveying mechanism; acquiring a first image of the object on the first platform via the first imaging unit; and performing defect inspection on the first image via the first inspection unit 301. The second inspection device 4 includes a second platform, a second imaging unit, and a second inspection unit 401, but does not have a conveying mechanism. The second imaging unit has the same configuration as the first imaging unit and captures a second image of the object placed on the second platform. The second inspection unit 401 uses the second image to create inspection data 51, which displays position information of a plurality of inspection areas in the object and displays inspection threshold values ​​for each inspection area. The first inspection unit 301 can perform defect inspections using the inspection data 51.

Description

[Technical Field]

[0001] This invention relates to an inspection system and inspection method. [Reference to related applications] This application claims priority to Japanese Patent Application JP2024-084086, filed on May 23, 2024, and the entire disclosure of Japanese Patent Application JP2024-084086 is incorporated herein by reference. [Previous Technology]

[0002] Conventional inspection devices use images of patterned printed circuit boards to detect defects. Typical inspection devices perform automatic inspections of numerous printed circuit boards sequentially. For example, an automatic inspection includes: transporting a printed circuit board to a stage using a transport mechanism; acquiring an image of the printed circuit board on the stage using an imaging unit; and performing defect inspection on the image using an inspection unit. On the other hand, when inspecting a new type of printed circuit board, inspection data is generated. This inspection data displays position information of multiple inspection areas on the printed circuit board and displays inspection threshold values ​​for each inspection area. Then, the inspection data is used to automatically inspect multiple printed circuit boards of that type.

[0003] Regarding the production of inspection data, Japanese Patent Application Publication No. 2001-43367 (Document 1) describes a computer, different from the image processing device in an appearance inspection system equipped with a camera and image processing device, capable of performing the same appearance inspection as the image processing device. This allows for offline evaluation of the inspection performance of the image processing software and facilitates the easy production of image processing software suitable for appearance inspection. Japanese Patent Application Publication No. 2006-84388 (Document 2) describes a method where a camera in an inspection device captures a sample substrate and obtains a sample image, which is then captured offline, independent of the inspection line established by the inspection device. Inspection data is then produced offline, thereby improving the operating rate of the inspection device. In the inspection machine disclosed in Japanese Patent Application Publication No. 2010-151463 (Document 3), during the inspection of the inspection object using pre-set inspection parameters, the image of the inspected object is used to virtually determine whether the object is good or not, and new inspection parameters are generated. Furthermore, Japanese Patent Application Publication No. 2010-92951 (Document 4) discloses a recipe preparation system for a length-measuring scanning electron microscope, which prepares the following recipe offline: the pattern of a semiconductor element is measured with high precision using semiconductor element design data.

[0004] However, when inspection data is generated offline, as in the inspection devices of Documents 1 and 2, it is possible to ensure, to some extent, the time available for automatic inspection by the inspection device. However, since the inspection device needs to photograph the printed circuit board and obtain images used for generating inspection data, it is not easy to extend this time further. When inspection data is generated using images of the inspected object after inspection, as in Document 3, it is impossible to generate inspection data when the design of the inspected object changes significantly. Therefore, the inspection machine on the actual production line side needs to obtain images used for generating inspection data, resulting in limited time available for automatic inspection. [Summary of the Invention]

[0005] The purpose of this invention is to extend the time that can be used by the inspection device for automatic inspection.

[0006] One embodiment of the present invention is an inspection system comprising: a first inspection device having a conveying mechanism, a first platform, a first imaging unit, and a first inspection unit, and performing automatic inspection, the automatic inspection comprising: conveying an object to the first platform by the conveying mechanism; acquiring a first image of the object on the first platform by the first imaging unit; and performing defect inspection on the first image by the first inspection unit; and a second inspection device having a second platform, a second imaging unit, and a second inspection unit, but without a conveying mechanism for conveying the object to the second platform; the second imaging unit having a light source, optical system, and imaging unit of the same type as those provided in the first imaging unit, and capturing an image of the object placed on the second platform and acquiring a second image; the second inspection unit using the second image to generate inspection data, the inspection data displaying position information of a plurality of inspection areas in the object and displaying inspection threshold values ​​for each inspection area; and the first inspection unit being capable of performing the defect inspection using the inspection data.

[0007] According to the present invention, the time available for automatic inspection by the first inspection device can be extended.

[0008] The second embodiment of the present invention is an inspection system as described in the first embodiment, wherein the first inspection unit performs the aforementioned defect inspection on the aforementioned first captured image using correction data, or the second inspection unit produces the aforementioned inspection data using the aforementioned correction data, wherein the aforementioned correction data corrects the difference in depth between the captured images of the aforementioned first imaging unit and the aforementioned second imaging unit.

[0009] The third aspect of the present invention is an inspection system as described in aspect one (or aspect one or two), which further includes: a shooting state monitoring unit, which monitors the difference between the state of the first shooting unit and the state of the second shooting unit based on a first shooting image of an object obtained by the first shooting unit and a second shooting image of the same object obtained by the second shooting unit.

[0010] The fourth aspect of the present invention is an inspection system as described in aspect one (or any one of aspect one to three), wherein the first imaging unit and the second imaging unit respectively use visible light to obtain a visible light image of the object and use infrared light to obtain an infrared light image of the object; the first inspection unit and the second inspection unit respectively use the visible light image and the infrared light image as the image to be captured.

[0011] The fifth aspect of the present invention is an inspection system as described in any one of aspects one to four, wherein it further comprises: an inspection data memory unit that stores the aforementioned inspection data; and the aforementioned first inspection unit and the aforementioned second inspection unit being able to communicate with the aforementioned inspection data memory unit.

[0012] Embodiment six of the present invention is an inspection method used in an inspection system; the aforementioned inspection system comprises: a first inspection device having a conveying mechanism, a first platform, a first imaging unit, and a first inspection unit, and performing automatic inspection, the aforementioned automatic inspection comprising: conveying an object to the aforementioned first platform by the conveying mechanism; acquiring a first image of the object on the aforementioned first platform by the aforementioned first imaging unit; and performing defect inspection on the aforementioned first image by the aforementioned first inspection unit; and a second inspection device having a second platform, a second imaging unit, and a second inspection unit, and not having the function of conveying the object to the aforementioned first platform. The conveying mechanism on the two platforms; the aforementioned second imaging unit has the same type of light source, optical system and imaging unit as the light source, optical system and imaging unit provided on the aforementioned first imaging unit; the aforementioned inspection method includes the following steps: taking a picture of an object placed on the aforementioned second platform by the aforementioned second imaging unit and obtaining a second image; using the aforementioned second image to create inspection data by the aforementioned second inspection unit, the aforementioned inspection data displaying the position information of a plurality of inspection areas in the aforementioned object and displaying the inspection threshold value for each inspection area; and performing the aforementioned defect inspection using the aforementioned inspection data in the aforementioned first inspection unit.

[0013] The seventh aspect of the present invention is an inspection method as described in aspect six, wherein when the part of the first imaging unit is replaced with a replacement part in the first inspection device, the replacement part is adjusted in the second imaging unit of the second inspection device and then the part of the first imaging unit is replaced with the replacement part.

[0014] The above-mentioned objects, as well as other objects, features, features and advantages, will become clearer with reference to the accompanying drawings and from the following detailed description of the invention.

Implementation Method

[0016] FIG1 is a block diagram showing the configuration of an inspection system 1 according to an embodiment of the present invention. The inspection system 1 is used to inspect printed circuit boards, and in one example, it is used for the final appearance inspection of printed circuit boards. The inspection system 1 can also be used for inspections other than the final appearance inspection. The inspection system 1 includes a first inspection device 3, a second inspection device 4, and an inspection data storage unit 5. The first inspection device 3, the second inspection device 4, and the inspection data storage unit 5 are interconnected via a network 8 such as a LAN (local area network) or the Internet.

[0017] The first inspection device 3 includes a first inspection body 31, a first control unit 30, and an image processing circuit (image processing engine) 38. The first control unit 30 is responsible for the overall control of the first inspection device 3. The first control unit 30 includes a first inspection unit 301. The first inspection unit 301 performs defect inspection on the printed circuit board 9. The function of the first control unit 30 is realized by the computer 39 (see Figure 2), which will be described later. The image processing circuit 38 performs predetermined image processing on the image of the object to be inspected. Details of the first inspection body 31 will be described later.

[0018] The second inspection device 4 includes a second inspection body 41, a second control unit 40, and an image processing circuit 48. The second control unit 40 is responsible for the overall control of the second inspection device 4. The second control unit 40 includes a second inspection unit 401 and an image capture status monitoring unit 402. The second inspection unit 401 performs defect inspection on the printed circuit board 9. The image capture status monitoring unit 402 is used in the processing example described later. The function of the second control unit 40 is realized by the computer 49 described later (see Figure 3). The image processing circuit 48 performs predetermined image processing on the image of the object being inspected. The image processing circuit 48 is an electrical circuit of the same type as the image processing circuit 38 of the first inspection device 3 (that is, the same electrical circuit is designed). Details of the second inspection body 41 will be described later.

[0019] The inspection data storage unit 5 is, for example, a NAS (Network Attached Storage) and is directly connected to the network 8. The inspection data storage unit 5 stores a plurality of inspection data 51. The inspection data 51 is used during defect inspection of the printed circuit board 9. The first correction data C1 and the second correction data C2 in FIG1 are generated in the processing example described later. According to the design of the inspection system 1, the inspection data storage unit 5 can also be implemented by other computer memory devices.

[0020] Figure 2 is a diagram showing the configuration of the first inspection device 3. The first inspection device 3 includes a first inspection body 31 and a computer 39. The computer 39 has a CPU (Central Processing Unit) and memory, and implements the functions of the first control unit 30 in Figure 1 by executing a predetermined program. All or part of the functions of the first control unit 30 can also be implemented by a dedicated electrical circuit. The image processing circuit 38 in Figure 1 is, for example, built into the computer 39.

[0021] The first inspection body 31 includes a first unit 32, a first moving mechanism 33, a first imaging unit 34, and a conveying mechanism 35. The first unit 32 holds the printed circuit board 9. Typically, the printed circuit board 9 is held horizontally on the first unit 32. The first moving mechanism 33 includes a ball screw, a guide rail, a motor, etc., and moves the first unit 32 in a generally horizontal direction along the main surface of the printed circuit board 9. In the example of FIG2, the first moving mechanism 33 is capable of moving the first unit 32 in two mutually orthogonal directions.

[0022] The first imaging unit 34 includes a light source 341, an optical system 342, and an imaging unit 343. The light source 341 emits light within a predetermined wavelength range. In this embodiment, the light source 341 emits white light covering all wavelength ranges of visible light, but it can also emit light covering other wavelength ranges. The imaging unit 343 has an imaging element such as a CCD (Charged Coupled Device) sensor or a CMOS (Complementary Metal Oxide Semiconductor) sensor. The optical system 342 includes a lens and a half mirror. The optical system 342 guides the light from the light source 341 to the printed circuit board 9 on the first unit 32, and causes reflected light from the printed circuit board 9 to enter the imaging unit 343. Thereby, the imaging unit 343 acquires an image (image data) of the printed circuit board 9. Hereinafter, the image of the printed circuit board 9 on the first unit 32 acquired by the first imaging unit 34 will be referred to as the "first image". The image acquired by the imaging unit 343 is a color image containing a plurality of color components (typically R (red), G (green), B (blue)). Depending on the design of the inspection system 1, it may also be a grayscale image.

[0023] In one example of the first imaging unit 34, the imaging unit 343 is a line sensor, and simultaneously acquires an image of a linear region extending in one direction on the main surface of the printed circuit board 9. The first moving mechanism 33 continuously moves the first unit 32 in a direction substantially perpendicular to the linear region, thereby acquiring a first image showing the entire printed circuit board 9. In the first inspection device 3, a plurality of first imaging units 34 may also be arranged along the length direction of the linear region, and the entire printed circuit board 9 may be captured by the plurality of first imaging units 34. Furthermore, a first image may also be acquired by moving the first imaging unit 34 relative to the printed circuit board 9. The same applies to the second imaging unit 44 (see Figure 3) described later.

[0024] The conveying mechanism 35 includes an adsorption section 351, a lifting section 352, and a moving mechanism 353. The adsorption section 351 holds the printed circuit board 9 by suction. The lifting section 352 has, for example, an air cylinder or a motor, and moves the adsorption section 351 in a generally vertical direction. The moving mechanism 353 has, for example, a ball screw, a guide rail, or a motor, and moves the adsorption section 351 and the lifting section 352 together in a generally horizontal direction.

[0025] In the first inspection device 3, an automatic inspection is performed on a plurality of printed circuit boards 9 in sequence. For example, a loading position P1 and a loading position P2 are provided below the moving mechanism 353, and the plurality of printed circuit boards 9 before inspection are placed on the loading position P1. After the suction part 351 is positioned above the loading position P1 by the moving mechanism 353, the suction part 351 is lowered by the lifting part 352 to hold the printed circuit board 9. After the suction part 351 is raised, the printed circuit board 9, the suction part 351, and the lifting part 352 are moved together to above the first stage 32 by the moving mechanism 353. Then, the suction part 351 is lowered by the lifting part 352 to release the suction holding of the printed circuit board 9, thereby placing the printed circuit board 9 on the first stage 32. In this way, the printed circuit board 9 is transported to the first stage 32 by the transport mechanism 35.

[0026] After the printed circuit board 9 is placed on the first stage 32, the first stage moving mechanism 33 moves the first stage 32 and captures an image of the printed circuit board 9 on the first stage 32 by the first imaging unit 34. This obtains a first image of the printed circuit board 9. The first image is input to the first inspection unit 301. In the first inspection unit 301, the first image is used to perform defect inspection on the printed circuit board 9. Inspection data 51 is used in the defect inspection. The inspection data 51 displays position information (including size) of a plurality of inspection areas in the printed circuit board 9 and displays inspection threshold values ​​for each inspection area. Details of the defect inspection and the inspection data 51 will be described later.

[0027] On the other hand, in the transport mechanism 35, after the printing substrate 9 is photographed, the adsorption part 351 adsorbs and holds the printing substrate 9 on the first stage 32. After the adsorption part 351 is raised, the printing substrate 9 moves together with the adsorption part 351 and the lifting part 352 to above the transport position P2. Then, the adsorption part 351 is lowered and the adsorption and holding of the printing substrate 9 is released, thereby placing the printing substrate 9 on the transport position P2. Afterwards, the next printing substrate 9 at the transport position P1 is transported to the first stage 32 in the same manner as described above.

[0028] As described above, the first inspection device 3 performs automatic inspection on a plurality of printed circuit boards 9 sequentially. This automatic inspection includes: transporting the printed circuit boards 9 to the first stage 32 via a transport mechanism 35; acquiring a first image of the printed circuit boards 9 on the first stage 32 via a first imaging unit 34; and performing defect inspection on the first image via a first inspection unit 301. Furthermore, in the first inspection device 3 of FIG2, a single mechanism performs the transport of the printed circuit boards 9 from the loading position P1 to the first stage 32 and the removal of the printed circuit boards 9 from the first stage 32 to the removal position P2. However, the transport mechanism 35 may also individually include: a loading mechanism for loading the printed circuit boards 9; and a removal mechanism for removing the printed circuit boards 9. Furthermore, the loading position P1 and the removal position P2 may also be provided separately from each other.

[0029] Figure 3 shows the configuration of the second inspection device 4. The second inspection device 4 includes a second inspection body 41 and a computer 49. In the example of Figure 3, the computer 49 body is housed inside the movable stage 81, and the second inspection body 41 is mounted on the top plate of the movable stage 81. The second inspection body 41 is desktop type. The computer 49 has a CPU and memory, etc., and performs the functions of the second control unit 40 in Figure 1 by executing a predetermined program. All or part of the functions of the second control unit 40 can also be implemented by a dedicated electrical circuit. The image processing circuit 48 in Figure 1 is, for example, built into the computer 49.

[0030] In this embodiment, the main components of computer 49 are the same as those of computer 39 in the first inspection device 3. That is, the CPU, ROM (Read Only Memory), RAM (Random Access Memory), GPU (Graphics Processing Unit), and motherboard of computer 49 are of the same type as those of computer 39. The display unit (monitor) and input unit may also be different. In the example of FIG3, the touch panel 491 of computer 49 is mounted on the frame 411 described later. According to the design of inspection system 1, the main components of computer 49 may also be different from those of computer 39.

[0031] The second inspection body 41 includes a second stage 42, a second stage moving mechanism 43, and a second imaging unit 44. The second stage 42 holds the printed circuit board 9. Typically, the printed circuit board 9 is held on the second stage 42 in a horizontal position. The second stage moving mechanism 43 includes a ball screw, a guide rail, a motor, etc., and moves the second stage 42 in a generally horizontal direction along the main surface of the printed circuit board 9. In the example of FIG3, the second stage moving mechanism 43 is capable of moving the second stage 42 in a direction perpendicular to the drawing. The second stage moving mechanism 43 may also be capable of moving the second stage 42 in multiple directions.

[0032] The second imaging unit 44 is mounted on a gate-shaped frame 411 and positioned above the second unit 42, the frame 411 spanning the second unit 42. The second imaging unit 44 includes a light source 441, an optical system 442, and an imaging unit 443. The light source 441, optical system 442, and imaging unit 443 are of the same type as those provided in the first imaging unit 34. The light source 441 emits light within a predetermined wavelength range. The imaging unit 443 has an imaging element, such as a CCD sensor or a CMOS sensor. The optical system 442 includes lenses and semi-mirrors. The optical system 442 guides the light from the light source 441 to the printed circuit board 9 on the second unit 42 and causes reflected light from the printed circuit board 9 to be incident on the imaging unit 443. Thereby, the imaging unit 443 acquires an image of the printed circuit board 9. Hereinafter, the image of the printed circuit board 9 on the second stage 42 acquired by the second imaging unit 44 will be referred to as the "second image". In one example of the second imaging unit 44, the imaging part 443 is a line sensor, and the second stage moving mechanism 43 moves the second stage 42 continuously to acquire a second image showing the entire printed circuit board 9.

[0033] The second inspection device 4 does not have a transport mechanism for transferring the printed circuit board 9 to the second table 42. Therefore, when inspecting the printed circuit board 9 in the second inspection device 4, the operator places the printed circuit board 9 on the second table 42. Then, the operator instructs the second control unit 40 to perform a shooting action via the touch panel 491, thereby capturing the printed circuit board 9 on the second table 42 by the second shooting unit 44 and obtaining a second captured image of the printed circuit board 9. The second inspection unit 401 uses the second captured image to perform defect inspection on the printed circuit board 9. Inspection data 51 is used in the defect inspection. After capturing the printed circuit board 9, the operator removes the printed circuit board 9 from the second table 42. As described above, the second inspection device 4 can perform manual inspection, which is performed by manually transferring the printed circuit board 9 to the second table 42. As described above, the second inspection device 4 can also perform defect inspection on the printed circuit board 9; however, in the processing example described later, the second inspection device 4 is used for the production of inspection data 51.

[0034] Next, the inspection process of the printed circuit board 9 in the inspection system 1 will be described with reference to FIG4. Since a new type of printed circuit board 9 (hereinafter referred to as "target printed circuit board 9") is being inspected here, inspection data 51 is first prepared, which is used for defect inspection of the target printed circuit board 9. Since the first inspection device 3 automatically inspects a plurality of printed circuit boards 9 of other types, the inspection data 51 of the target printed circuit board 9 is prepared in the second inspection device 4.

[0035] In the production of inspection data 51, firstly, the CAM (computer-aided manufacturing) data (substrate design data) of the target printed circuit board 9 is input to the second inspection device 4 via, for example, the network 8 in FIG1, and loaded (memorized) in the second inspection unit 401 (step S11). Next, a plurality of (for example, ten to twenty) target printed circuit boards 9 are sequentially photographed by the second imaging unit 44 (step S12). In the second inspection device 4, the operator places the target printed circuit boards 9 one by one onto the second table 42 and obtains a plurality of second photographed images showing the plurality of target printed circuit boards 9.

[0036] The second inspection unit 401 averages a plurality of second captured images to generate a main image of the second captured images (referencing the image). The value of each pixel in the main image is the average value of the corresponding pixel values ​​in the plurality of second captured images, etc. It is not necessary to generate the main image from a plurality of second captured images; when the second captured images contain few defects, the original state of the second captured images can also be used as the main image.

[0037] Next, the main image and the image shown in the CAM data are aligned (step S13). In this processing example, a plurality of marks are provided on the outer edge of the object printed circuit board 9, and one image is moved (moved in the direction of pixel arrangement), rotated and stretched relative to another image in such a way that the positions of the plurality of marks are consistent in the main image and the image shown in the CAM data.

[0038] Figure 5 is a diagram showing a portion of the main image of the target printed circuit board 9. In the printed circuit board 9, a wiring pattern made of metal such as copper is formed on a resin substrate, and a solder resist layer is also formed, which covers most of the substrate and the wiring pattern (e.g., the area excluding the plating portion 95 described later). Text, marks, etc. are printed on a portion of the solder resist layer using silk ink. The main image of the target printed circuit board 9 includes a plating portion 95 (also called a pad portion since it is mainly a pad), a first solder resist portion 96, a second solder resist portion 97, and a silk ink portion 98 as individual inspection areas (step S14). The plating portion 95 is the portion of the exposed wiring pattern, the first solder resist portion 96 is the lower layer of the solder resist layer that is the wiring pattern, the second solder resist portion 97 is the portion of the solder resist layer that is in direct contact with the substrate, and the silk ink portion 98 is the text, marks, etc. printed on the solder resist layer. The CAM data system includes a layer displaying wiring patterns, a layer displaying solder resist layers, and a layer displaying text, symbols, etc. of screen printing ink. The second inspection unit 401 can utilize the CAM data to specifically plate the plating section 95, the first solder resist section 96, the second solder resist section 97, and the screen printing section 98.

[0039] In this processing example, high-sensitivity areas and low-sensitivity areas are also set in the inspection areas. For example, as shown in FIG6, the portion of the first solder resist portion 96 in the main image whose width is less than a predetermined value (the white area of ​​the additional symbol 961 in FIG6) is set as a high-sensitivity area. The remaining portion of the first solder resist portion 96 is set as a low-sensitivity area. High-sensitivity areas and low-sensitivity areas are also set for the second solder resist portion 97 in the same way. In addition, in the plating portion 95, the portion with an area less than a predetermined value is set as a high-sensitivity area, and the remaining portion of the plating portion 95 is set as a low-sensitivity area. It is also possible to use CAM data to specify the high-sensitivity areas and low-sensitivity areas in each inspection area. In addition, for some inspection areas (such as the silkscreen portion 98, etc.), high-sensitivity areas and low-sensitivity areas may not be set.

[0040] Next, inspection threshold values ​​are set for each inspection area. In this processing example, since multiple inspections are performed on each inspection area, inspection threshold values ​​are set for each type of inspection. Multiple inspections are described here. Multiple inspections include, for example, comparison inspection, foreign object inspection, and unevenness inspection. In comparison inspection, the shape of the inspection area in the image of the object to be inspected is compared with the shape of the inspection area in the main image. In one example, an image showing the difference between the inspection area in the binary image obtained by binarizing the image of the object to be inspected and the inspection area in the binary image obtained by binarizing the main image is obtained. Then, areas in the image that exceed the size threshold value used for comparison inspection are detected as defects.

[0041] In foreign object inspection, the hue value of each position in the inspection area is obtained for each color component in the image of the object being inspected. Regions in the set (region) where the hue value is outside the range of the hue threshold values ​​(upper and lower limits) used for foreign object inspection are identified as defects. In unevenness inspection, the color of each position in the inspection area of ​​the image of the object being inspected is compared with the color of that position in the main image. Then, regions in the set (region) where the color difference is above the hue threshold value used for unevenness inspection are identified as defects. Furthermore, comparison inspection, foreign object inspection, and unevenness inspection can also be performed using other known methods.

[0042] Figure 7 is a diagram showing an example of inspection threshold values ​​for an inspection area. The inspection threshold values ​​for each inspection area are set separately for low-sensitivity and high-sensitivity areas for each type of inspection. In the example of Figure 7, defects in the unevenness inspection of the first solder resist section 96 are divided into dark defects and bright defects. The dark defects are darker than the corresponding area in the main image, and the bright defects are brighter than the corresponding area. Therefore, size threshold values ​​and hue threshold values ​​(refer to the "Dark Defect Size" and "Dark Defect Sensitivity" fields in Figure 7) are set as inspection threshold values ​​for dark defects in the unevenness inspection in the low-sensitivity and high-sensitivity areas, respectively. Size threshold values ​​and hue threshold values ​​(refer to the "Bright Defect Size" and "Bright Defect Sensitivity" fields in Figure 7) are also set as inspection threshold values ​​for bright defects in the unevenness inspection. The same inspection threshold values ​​are set for comparison inspection and foreign object inspection. The inspection threshold values ​​are set, for example, by operator input via the input section of the computer 49. In the second inspection unit 401, the inspection threshold value set by the operator can also be used to perform defect inspection on the second captured image obtained in step S12. If there are many false alarms (detection of false defects) in the result of the defect inspection, the operator can adjust the current threshold value to an inspection threshold value that can reduce false alarms.

[0043] Through the above processing, inspection data 51 is generated using the second captured image by the second inspection unit 401 (step S15). The inspection data 51 displays position information of a plurality of inspection areas in the target printed circuit board 9 and displays the inspection threshold value for each inspection area. In this processing example, the inspection data 51 includes the main image. The inspection data 51 is input via the network 8 and stored in the inspection data storage unit 5. The inspection system 1 can also perform inspections other than comparative inspection, foreign object inspection, and unevenness inspection, and can also perform different inspections on a plurality of inspection areas. In addition, the inspection data 51 may also include inspection parameters such as the shooting conditions during inspection (light intensity of the light source unit 441, etc.) and various image processing conditions for the captured image. During the generation of the inspection data 51, the inspection parameters are also adjusted as needed.

[0044] When automatically inspecting a plurality of (numerous) target printed circuit boards 9 in the first inspection device 3, the plurality of target printed circuit boards 9 are placed in the loading position P1. Furthermore, the inspection data 51 of the target printed circuit boards 9 is input from the inspection data memory unit 5 to the first inspection unit 301. As described above, the configuration of the first imaging unit 34 is the same as that of the second imaging unit 44. Furthermore, the defect inspection program in the first inspection unit 301 is the same as that in the second inspection unit 401. Therefore, the inspection data 51 generated by the second inspection unit 401 can be directly used in the first inspection unit 301.

[0045] Subsequently, an automatic inspection is performed sequentially on a plurality of target printed circuit boards 9. The automatic inspection includes: transporting the target printed circuit boards 9 to the first unit 32 by the transport mechanism 35; acquiring a first image of the target printed circuit boards 9 on the first unit 32 by the first imaging unit 34; and performing a defect inspection on the first image by the first inspection unit 301. At this time, the defect inspection performed by the first inspection unit 301 is performed using the inspection data 51 of the target printed circuit boards 9 produced in the second inspection unit 401 (step S16). After performing defect inspection on all target printed circuit boards 9 at the transport position P1, the inspection process of FIG4 is completed.

[0046] Here, it is assumed that the comparative example inspection system omitting the second inspection device 4 is omitted. In the comparative example inspection system, inspection data 51 for the target printed circuit board 9 is produced in the first inspection device 3. Since producing new inspection data 51 takes, for example, twenty to thirty minutes, the first inspection device 3 occupies the time for producing inspection data 51, causing automatic inspection (mass production inspection) to stop. As a result, the number of target printed circuit boards 9 that are automatically inspected in the first inspection device 3 decreases. In multi-variety, small-batch production, sometimes, for example, twenty to thirty varieties of new inspection data 51 need to be produced per day. In this case, about half of the daily operating time of the first inspection device 3 is spent on producing inspection data 51. Although it is also thought that a first inspection device 3 for producing inspection data 51 should be added, the cost of the inspection system is greatly increased because the first inspection device 3 is very expensive.

[0047] In contrast, the inspection system 1 in FIG1 includes a first inspection device 3 and a second inspection device 4; the first inspection device 3 has a conveying mechanism 35, a first stage 32, a first imaging unit 34 and a first inspection section 301 and performs automatic inspection; the second inspection device 4 has a second stage 42, a second imaging unit 44 and a second inspection section 401, but does not have a conveying mechanism for conveying the printed circuit board 9 to the second stage 42. In addition, the second imaging unit 44 has a light source 341, an optical system 342 and an imaging section 343 of the same type as those provided in the first imaging unit 34, and it captures images of the printed circuit board 9 placed on the second stage 42 and obtains a second image. Furthermore, the second inspection unit 401 uses the second captured image to generate inspection data 51, which displays the position information of a plurality of inspection areas in the printed circuit board 9 and displays the inspection threshold value for each inspection area. The first inspection unit 301 can perform defect inspection using the inspection data 51.

[0048] In the inspection system 1, the time required to produce the inspection data 51 in the first inspection device 3 can be omitted or shortened, and the time available for the first inspection device 3 to perform automatic inspection can be extended. As a result, the printed circuit board 9 can be inspected efficiently even when producing multiple varieties in small quantities. Furthermore, since the second inspection device 4 does not have a conveying mechanism, the manufacturing cost of the inspection system 1 can be significantly reduced compared to adding the first inspection device 3 (i.e., setting up multiple first inspection devices 3). In addition, the second inspection device 4 can also be used as an independent inspection device. During periods when the production of the inspection data 51 is not being performed, the second inspection device 4 can be used as a manual inspection device, thereby increasing the throughput of mass production inspections. Furthermore, the inspection data 51 can also be produced by the first inspection unit 301 during periods when the operating rate of the first inspection device 3 is low.

[0049] Preferably, the inspection system 1 further includes an inspection data memory unit 5 for storing inspection data 51, and the first inspection unit 301 and the second inspection unit 401 are able to communicate with the inspection data memory unit 5. In other words, the inspection data 51 is shared between the first inspection unit 301 and the second inspection unit 401 via the inspection data memory unit 5. If the inspection data 51 is stored in the first inspection unit 301 or the second inspection unit 401, the load applied to the first inspection unit 301 and the second inspection unit 401 when reading the inspection data 51 from the outside may cause obstacles to the inspection of the printed circuit board 9. In contrast, by providing a dedicated memory unit (inspection data memory unit 5) as described above, excessive load is not applied to the first inspection unit 301 and the second inspection unit 401, and the inspection data 51 can be easily handled. Furthermore, according to the design of the inspection system 1, the inspection data 51 can also be stored in the first inspection unit 301 and / or the second inspection unit 401, and the inspection data storage unit 5 can be omitted.

[0050] The inspection method in Figure 4 includes the following steps: taking a picture of the printed circuit board 9 placed on the second stage 42 by the second imaging unit 44 and obtaining a second image; using the second image to create inspection data 51 for the printed circuit board 9 by the second inspection unit 401; and performing a defect inspection using the inspection data 51 in the first inspection unit 301. This allows the time required to create the inspection data 51 in the first inspection device 3 to be omitted or shortened, and extends the time available for automatic inspection by the first inspection device 3.

[0051] The first imaging unit 34 and the second imaging unit 44 described above use light source units 341 and 441 that emit visible light. However, light source units that emit infrared light may also be additionally provided in the light source units 341 and 441. In this case, the first imaging unit 34 and the second imaging unit 44 respectively use visible light to obtain a visible light image of the printed circuit board 9 and use infrared light to obtain an infrared light image of the printed circuit board 9.

[0052] When creating inspection data 51, in the second inspection device 4, a visible light image is acquired when the second stage 42 moves continuously in one direction, and an infrared light image is acquired when the second stage 42 moves continuously in the opposite direction. In the second inspection unit 401, master images are created from the visible light image and the infrared light image respectively, and inspection threshold values ​​are set for each inspection area. In other words, the visible light image and the infrared light image are used as second captured images to create inspection data 51. In the automatic inspection of the first inspection device 3, similarly to the second inspection device 4, a visible light image is acquired when the first stage 32 moves continuously in one direction, and an infrared light image is acquired when the first stage 32 moves continuously in the opposite direction. Defect inspection is performed on the visible light image and the infrared light image respectively in the first inspection unit 301. In other words, defect inspection is performed using the visible light image and the infrared light image as first captured images.

[0053] When acquiring visible light and infrared light images as described above, the time required for acquiring the images and producing the inspection data 51 increases. In this case, the time required for producing the inspection data 51 in the inspection system 1, which also captures images of the printed circuit board 9 in the second inspection device 4, can be omitted or shortened in the first inspection device 3, and the time available for automatic inspection by the first inspection device 3 can be extended. Furthermore, by using infrared light, an image can be obtained in which the solder resist layer becomes substantially transparent, thereby enabling the detection of defects in the underlying layer of the solder resist layer. As a result, high-precision inspection can be performed using visible light and infrared light images. In the first imaging unit 34 and the second imaging unit 44, an imaging unit for visible light images and an imaging unit for infrared light images can also be provided separately. In this case, the same type of imaging unit for visible light images and the same type of imaging unit for infrared light images are used in both the first imaging unit 34 and the second imaging unit 44.

[0054] Next, the following processing will be explained: When the same printed circuit board 9 is photographed by the first imaging unit 34 and the second imaging unit 44, if a difference in shade is generated between the first and second photographed images due to individual differences in their respective components, the difference in shade is corrected. This difference in shade includes, for example, differences in dynamic range and differences in gamma curve. Since the first and second photographed images are color images, the differences in shade for R, G, and B are corrected respectively. As described above, the first and second photographed images may also be grayscale images; in this case, the difference in shade is corrected using the same processing as described below.

[0055] Figure 8 shows the color map 71. In the color map 71, a plurality of blocks 711 (24 in Figure 8) are assigned different colors, and the hue values ​​of R, G, and B are defined for each block 711. In the following description, the color that follows the variation of the hue values ​​of R, G, and B defined in the color map 71 is referred to as the "true color".

[0056] First, a color map 71 is captured by a second imaging unit 44 in the second inspection device 4. This obtains a second captured image displaying the color map 71, and assigns specific R, G, and B hue values ​​to each of the plurality of blocks 711. A table is then obtained, as shown in FIG. 9, which assigns a correspondence between the R, G, and B hue values ​​of the true color displayed in each block 711 and the R, G, and B hue values ​​displayed in the second captured image. In the second inspection unit 401, for example, the difference between the hue value of the true color of each block 711 and the hue value of the second captured image is calculated for each color component, thereby obtaining second correction data C2. This second correction data C2 displays the correspondence between the hue values ​​of the second captured image and the hue values ​​of the true color (i.e., the second correction data C2 is capable of converting the hue values ​​of the second captured image and the hue values ​​of the true color). The second correction data C2 can also be obtained by various known methods, and can be a table, function, etc. (similarly as in the first correction data C1 described later).

[0057] In the first inspection device 3, the color map 71 is also captured by the first imaging unit 34, and a first captured image displaying the color map 71 is obtained. In the first inspection unit 301, for example, the difference between the hue value of the true color of block 711 and the hue value of the first captured image is calculated for each color component, thereby obtaining first correction data C1. The first correction data C1 shows the correspondence between the hue value of the first captured image and the hue value of the true color. In this processing example, as shown in FIG1, the first correction data C1 and the second correction data C2 are stored in the inspection data storage unit 5.

[0058] In the inspection process of the target printed circuit board 9 as shown in FIG. 4, inspection data 51 is generated in the second inspection device 4 without using the second correction data C2 (steps S11 to S15). When the first inspection device 3 performs automatic inspection on a plurality of target printed circuit boards 9 (step S16), the inspection data 51, the first correction data C1, and the second correction data C2 of the target printed circuit board 9 are input from the inspection data memory unit 5 to the first inspection unit 301. In the first inspection unit 301, the main image contained in the inspection data 51 is converted using the second correction data C2. Thereby, when the target printed circuit board 9 is assumed to have acquired a main image by the second imaging unit 44, an image is obtained that roughly shows the true color of the target printed circuit board 9 in terms of the R, G, and B hue values. Then, the image is converted using the first correction data C1. Therefore, when the object printed circuit board 9 is assumed to have acquired the main image by the second imaging unit 44, an image that approximates the object printed circuit board 9 as the image captured and acquired by the first imaging unit 34 (i.e., an image that follows the tonal characteristics of the first imaging unit 34) is obtained as the converted main image. In addition, similarly to the main image, the tonal threshold values ​​contained in the inspection data 51 are also converted using the second correction data C2 and the first correction data C1.

[0059] In the automatic inspection of the first inspection device 3, an automatic inspection is performed sequentially on a plurality of target printed circuit boards 9. The automatic inspection includes: transporting the target printed circuit boards 9 to the first stage 32 by a conveying mechanism 35; acquiring a first photographic image of the target printed circuit boards 9 on the first stage 32 by a first imaging unit 34; and performing defect inspection on the first photographic image by a first inspection unit 301. At this time, in the first inspection unit 301, a defect inspection is performed on the plurality of (numerous) first photographic images using a converted main image and a converted tone threshold value. In this way, even if there is a difference in depth between the first photographic image acquired by the first imaging unit 34 and the second photographic image acquired by the second imaging unit 44, the first photographic image is appropriately inspected for defects using inspection data 51 generated based on the second photographic image.

[0060] As described above, in the preferred inspection system 1, the first inspection unit 301 performs defect inspection on the first captured image using the following correction data (first correction data C1 and second correction data C2 mentioned above): the correction data corrects the difference in depth between the captured images of the first imaging unit 34 and the second imaging unit 44. This allows for high-precision defect inspection using the inspection data 51 generated in the second inspection device 4 within the first inspection unit 301. Furthermore, the following correction data can be generated and a converted main image conforming to the tonal characteristics of the first imaging unit 34 can be obtained by converting the main image once: the correction data displays the correspondence between the tonal values ​​of the first captured image and the tonal values ​​of the second captured image.

[0061] In the inspection system 1, when creating the inspection data 51, the second inspection unit 401 can also use the second correction data C2 and the first correction data C1 to convert the second captured image and obtain an image that conforms to the tone characteristics of the first capturing unit 34. In this case, a main image is generated based on the image, and tone thresholds (and size thresholds) are set to create the inspection data 51. The inspection data 51 is then directly used in the first inspection unit 301. Thus, when the second inspection unit 401 uses correction data (first correction data C1 and second correction data C2) to create the inspection data 51, defect inspection using the inspection data 51 can also be performed with high accuracy in the first inspection unit 301. Furthermore, according to the design of the inspection system 1, it is also possible for the second inspection unit 401 to use the second correction data C2 to create the inspection data 51 that conforms to the tone characteristics of the true color, and for the first inspection unit 301 to use the first correction data C1 to generate a first captured image that conforms to the tone characteristics of the true color, thereby performing defect inspection.

[0062] Next, the process of monitoring the status of the first imaging unit 34 while continuing automatic inspection in the first inspection device 3 will be described. In this example, the imaging status monitoring unit 402 in FIG1 is used. Furthermore, in the normal state of the first imaging unit 34 and the second imaging unit 44, there is almost no difference in depth between the first and second images.

[0063] The status of the second imaging unit 44 is checked periodically in the second inspection device 4, for example. In one example of checking the status of the second imaging unit 44, the color map 71 of Figure 8 is captured by the second imaging unit 44. Then, it is checked whether the hue values ​​of each color component of the second captured image output by the second imaging unit 44 are approximately consistent with the hue values ​​of the second captured image obtained from the previously captured color map 71 (the output of the second imaging unit 44 in normal condition), that is, whether the status of the second imaging unit 44 is maintained normally. If the status of the second imaging unit 44 is abnormal, predetermined maintenance work is performed. In this way, the status of the second imaging unit 44 is maintained normally.

[0064] Automatic inspection continues in the first inspection device 3. The operator removes the printed circuit board 9, which has been photographed by the first imaging unit 34, and places it on the second unit 42 of the second inspection device 4. Then, the second imaging unit 44 photographs the printed circuit board 9 and obtains a second image. Furthermore, the first image of the printed circuit board 9 is input to the imaging status monitoring unit 402 of the second inspection device 4 via the network 8. The imaging status monitoring unit 402 compares the first image and the second image of the printed circuit board 9 and calculates and displays the difference between the two images.

[0065] The calculation of the difference value is, for example, the sum of squares of the differences in the hue values ​​of all pixels for each color component between the first captured image and the second captured image. If the sum of squares is greater than a predetermined value, it is determined that there is a difference (large difference) between the state of the first capturing unit 34 and the state of the second capturing unit 44, and the operator is notified to promote the maintenance of the first capturing unit 34. The notification to the operator is performed by a well-known method such as displaying on the touch panel 491 of the second inspection device 4. If the sum of squares is less than or equal to a predetermined value, it is determined that there is no difference (small difference) between the state of the first capturing unit 34 and the state of the second capturing unit 44, and the operator is not notified. The value of the difference can also be a value other than the sum of squares of the differences in hue values. In addition, in the capturing status monitoring unit 402, it is also possible to determine whether there is a difference between the state of the first capturing unit 34 and the state of the second capturing unit 44 by comparing the average hue value, contrast value, and other values ​​(comparison values) of the first captured image with the values ​​of the second captured image.

[0066] As described above, the imaging state monitoring unit 402 monitors the difference between the states of the first imaging unit 34 and the second imaging unit 44 based on a first image of a printed circuit board 9 acquired by the first imaging unit 34 and a second image of the same printed circuit board 9 acquired by the second imaging unit 44. This allows the automatic inspection in the first inspection device 3 to continue while maintaining the normal state of the second imaging unit 44, and makes it easy to detect changes in the state of the first imaging unit 34 (abnormalities). Furthermore, even in the normal state of the first imaging unit 34 and the second imaging unit 44, there may be differences in depth between the first and second images. In this case, correction data (first correction data C1 and second correction data C2) can be used to correct the first and / or second images, and the difference between the states of the first imaging unit 34 and the second imaging unit 44 can be monitored based on the corrected images.

[0067] Next, a preferred procedure for replacing a part in the first imaging unit 34 of the first inspection device 3 in the inspection system 1 will be described. In the following description, the part that replaces and installs the part in the first imaging unit 34 will be referred to as a "replacement part". The replacement part can be a new part or a reused part.

[0068] When replacing parts in the first imaging unit 34, firstly, the replacement part is replaced with the corresponding part in the second imaging unit 44 of the second inspection device 4. Then, a predetermined adjustment of the replacement part is performed in the second imaging unit 44. For example, if the replacement part is a light source and the intensity of the emitted light needs to be adjusted, the intensity of the emitted light is adjusted (e.g., the input current value is adjusted) while the replacement part is installed in the second imaging unit 44. After the adjustment of the replacement part is completed, the replacement part is removed from the second imaging unit 44 and replaced with the parts in the first imaging unit 34. The replacement part may be the entire light source or a part of the light source. In addition, the replacement part may be all or part of the optical system or the imaging unit. For example, if the focusing mechanism, which is part of the optical system, is the replacement part, then after mechanical adjustments are made in the focusing mechanism in the second imaging unit 44, the focusing mechanism is replaced with the corresponding part in the first imaging unit 34.

[0069] As described above, in the preferred inspection system 1, when the part of the first imaging unit 34 is replaced with a replacement part in the first inspection device 3, the second imaging unit 44 in the second inspection device 4 adjusts the replacement part, thereby replacing the part of the first imaging unit 34 with the replacement part. Since the adjustment of the replacement part is completed in the second imaging unit 44, which has the same configuration as the first imaging unit 34, the time required for adjusting the replacement part in the first imaging unit 34 can be shortened or eliminated. As a result, the first inspection device 3 can be restored in a short time, thereby extending the time that the first inspection device 3 can be used for automatic inspection.

[0070] Various changes can be made to the above-mentioned inspection system 1 and inspection method.

[0071] In the inspection system 1 described above, when using the correction data (first correction data C1 and second correction data C2) between the first shooting unit 34 and the second shooting unit 44 to correct the difference in depth of the captured image, all or part of the types of the light source 441, optical system 442 and shooting unit 443 provided in the second shooting unit 44 may also be different from those of the first shooting unit 34.

[0072] As described above, the first unit 32 in the first inspection device 3 only needs to move relative to the first imaging unit 34. Furthermore, depending on the size of the printed circuit board 9 to be imaged, a first image of the printed circuit board 9 can be obtained without moving the first unit 32. In this case, the first unit moving mechanism 33 can be omitted. The same applies to the second inspection device 4.

[0073] In the above embodiment, the printed circuit board 9 is the object of inspection in the inspection system 1. However, the object of inspection may be a glass substrate, a semiconductor substrate, or a component other than a substrate, such as a mechanical part, in addition to the printed circuit board 9.

[0074] The above-mentioned embodiments and the components in each variation can be appropriately combined as long as they do not contradict each other.

[0075] Although the invention has been described and illustrated in detail, these descriptions are illustrative and not limiting. Therefore, various variations and configurations are to be considered as long as one does not depart from the scope of the invention. [Simplified Explanation of the Diagram]

[0015] [Figure 1] is a block diagram showing the structure of the inspection system. [Figure 2] is a diagram showing the structure of the first inspection device. [Figure 3] is a diagram showing the structure of the second inspection device. [Figure 4] is a flowchart showing the inspection process of the printed circuit board. [Figure 5] is a diagram showing the main image of the target printed circuit board. [Figure 6] is a diagram showing the high-sensitivity area of ​​the first solder resist in the main image. [Figure 7] is a diagram showing an example of the inspection threshold value for the inspection area. [Figure 8] is a diagram showing the color chart. [Figure 9] is a table showing the true color of each patch and the color of the second captured image.

Claims

1. An inspection system comprising: a first inspection apparatus having a conveying mechanism, a first table, a first imaging unit, and a first inspection section, and performing automatic inspection, the automatic inspection comprising: conveying a printed circuit board to the first table by the conveying mechanism; acquiring a first image of the printed circuit board on the first table by the first imaging unit; and performing defect inspection on the first image by the first inspection section; and a second inspection apparatus having a second table, a second imaging unit, and a second inspection section, but without a conveying mechanism for conveying the printed circuit board to the second table; the second imaging unit having a light source, optical system, and imaging section of the same type as those provided in the first imaging unit, and capturing an image of the printed circuit board placed on the second table and acquiring a second image; the second inspection section using the second image to generate inspection data, the inspection data displaying position information of a plurality of inspection areas in the printed circuit board and displaying inspection threshold values ​​for each inspection area; and the first inspection section being capable of performing the defect inspection using the inspection data. The aforementioned second inspection device generates the aforementioned inspection data during the aforementioned automatic inspection of a plurality of printed circuit boards of the first type by the aforementioned first inspection device. The aforementioned inspection data is used in the aforementioned automatic inspection of a plurality of printed circuit boards of the second type, which are new types different from the aforementioned first type. The aforementioned first inspection device directly utilizes the aforementioned inspection data generated by the aforementioned second inspection device when performing the aforementioned automatic inspection of a plurality of printed circuit boards of the second type.

2. The inspection system as described in claim 1, wherein the aforementioned first inspection unit performs the aforementioned defect inspection on the aforementioned first captured image using correction data, or the aforementioned second inspection unit produces the aforementioned inspection data using the aforementioned correction data, wherein the aforementioned correction data corrects the difference in depth between the captured images of the aforementioned first imaging unit and the aforementioned second imaging unit.

3. The inspection system as described in claim 1, further comprising: an image capture status monitoring unit, which monitors the difference between the status of the first image capture unit and the status of the second image capture unit based on a first image of a printed circuit board obtained by the first image capture unit and a second image of the same printed circuit board obtained by the second image capture unit.

4. The inspection system as described in claim 1, wherein the first imaging unit and the second imaging unit respectively acquire a visible light image of the printed circuit board using visible light and acquire an infrared light image of the printed circuit board using infrared light; and the first inspection unit and the second inspection unit respectively use the visible light image and the infrared light image as the captured image.

5. The inspection system described in any one of claims 1 to 4 further comprises: an inspection data memory unit that stores the aforementioned inspection data; and the aforementioned first inspection unit and the aforementioned second inspection unit being able to communicate with the aforementioned inspection data memory unit.

Images