Hair inspection device for a substrate and hair inspection method for a substrate

Abstract

Provided is a hair inspection device for a substrate or the like, which does not exclude a region including a circuit pattern from an inspection target, can more reliably prevent a circuit pattern, a step, or a damage from being erroneously detected as a hair, and can highly accurately detect a hair including a blond hair and a brown hair. In a post-solder printing inspection device (13), a color image related to an inspected substrate is acquired, and a hue image and a chroma image are obtained using the color image. Then, in at least a resist region of the obtained hue image, a hair including a brown hair and / or a blond hair is detected as a first hair using a hue difference with respect to the resist region. In addition, in at least the resist region of the obtained chroma image, a hair including a black hair and / or a white hair is detected as a second hair using a chroma difference with respect to the resist region. The detection of the first hair and the second hair is performed without using a lightness image of the inspected substrate and based only on the hue image and the chroma image.

Description

Technical Field

[0001] This invention relates to an apparatus and method for inspecting the presence of hairs in the resist areas of a printed circuit board. Background Technology

[0002] The printed circuit board includes a flat substrate, circuit patterns and pads formed on the surface of the substrate, and an insulating resist coated on the surface of the substrate, excluding the pads, etc.

[0003] Typically, in a substrate production line where components (such as electronic components) are mounted on a printed circuit board, solder paste is first printed onto the pads (solder printing process). Next, the components are temporarily fixed onto the printed circuit board based on the adhesive properties of the solder paste (mounting process). Then, the printed circuit board is guided to a reflow oven where the solder paste is heated and melted for soldering (reflow process).

[0004] Typically, in such substrate production lines, the presence of foreign objects in the printed circuit board is checked based on image data obtained by photographing the printed circuit board with solder paste. Examples of foreign objects include hair. If hair adheres to an area of ​​the printed circuit board where resist is provided (hereinafter referred to as the "resist area"), the hair will carbonize during heating in the reflow oven, potentially causing short circuits between multiple pads due to the carbonized hair.

[0005] Therefore, as a method for detecting foreign objects such as hair, a method has been proposed, for example, to detect a first foreign object (a foreign object with a bright attribute) and a second foreign object (a foreign object with a dark attribute) using lightness and chroma (for example, see Patent Document 1, etc.).

[0006] To further explain the foreign object detection method described in Patent Document 1, firstly, multiple main images, differentiated by color, related to the main substrate are acquired using multiple colored lights. The brightness values ​​of these color-differentiated main images are then merged pixel-wise to obtain a main substrate image. Secondly, multiple measurement images, differentiated by color, related to the printed circuit board (measurement board) to be inspected are acquired using multiple colored lights. The brightness values ​​of these color-differentiated measurement images are then merged pixel-wise to obtain a measurement board image. In other words, images related to the brightness of both the main substrate and the measurement board are acquired separately. Then, a first foreign object is detected based on the difference (i.e., the difference in brightness) between the main substrate image and the measurement board image.

[0007] Furthermore, a chroma map associated with the main substrate is formed using a color-differentiated main image, and a chroma map associated with the measurement substrate is formed using a color-differentiated measurement image. That is, chroma-related images of the main substrate and the measurement substrate are acquired separately. Then, the second foreign substance is detected based on the differences in these chroma maps.

[0008] In addition, Patent Document 1 describes, along with the above method, the exclusion of areas containing holes and areas containing circuit patterns in the printed circuit board from the inspection object.

[0009] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2017-125861 Summary of the Invention

[0010] The problem the invention aims to solve However, in the method described in Patent Document 1, the difference between the main substrate image and the measured substrate image (i.e., the difference in images related to brightness) is detected not only for differences related to the presence or absence of hair, but also for differences related to circuit patterns, height differences, or damage. Therefore, it is possible to misdetect circuit patterns, height differences, or damage as hair. In addition, since resists are generally translucent, not only height differences on the surface of the resist, but also height differences under the resist can be misdetected as hair.

[0011] In contrast, consider excluding areas containing circuit patterns from the inspection scope. However, in this case, it's impossible to check for hair in the excluded areas. Furthermore, even if it's possible to prevent circuit patterns or resulting height / difference errors from being detected as hair, damage can still be mistakenly detected as hair. Moreover, the process for excluding areas containing circuit patterns from the inspection scope can become extremely complex.

[0012] Furthermore, when various hair colors such as black, brown, white, and blonde are present, the difference in lightness and chroma between brown and blonde hair and the resist area tends to be relatively small. Therefore, in methods that utilize lightness and chroma as described above, the detection accuracy of brown and blonde hair adhering to the resist area may become insufficient.

[0013] The present invention was made in view of the above circumstances, and its object is to provide a hair inspection device for a substrate, which can more reliably prevent the misdetection of circuit patterns, height differences, and damage as hair without excluding areas containing circuit patterns from the inspection object, and can detect hair including blond and brown hair with high accuracy.

[0014] means for solving problems The following sections provide a detailed explanation of each solution suitable for achieving the aforementioned objectives. Additionally, the unique effects of each solution will be noted as needed.

[0015] Solution 1. A hair inspection apparatus for a substrate, for inspecting at least the presence of hair in a printed circuit board having a green resist area and a solder paste printed thereon, characterized in that it comprises: A color image acquisition unit uses multiple colored lights to acquire a color image related to a substrate under inspection, wherein the substrate under inspection is the printed substrate that is the object of inspection. A hue image acquisition unit uses the color image to obtain a hue image of the substrate under inspection; A chroma image acquisition unit uses the color image to obtain a chroma image of the substrate under inspection; A first hair detection unit, in at least the resist region of the hue image, is capable of detecting hairs comprising at least brown and / or blonde hair as first hairs using hue differences relative to the resist region; and The second hair detection unit is capable of detecting hairs containing at least black and / or white hair as second hairs in at least the resist region of the chroma image using the chroma difference relative to the resist region. The first hair detection unit is configured to detect the first hair based solely on the hue image without using the brightness image of the substrate being inspected. The second hair detection unit is configured to detect the second hair based solely on the chroma image without using the brightness image of the substrate being inspected.

[0016] According to Scheme 1 above, in at least the resist region of the hue image, hairs containing at least brown and / or blonde hair can be detected as first hairs by utilizing the hue difference with the resist region. That is, considering that first hairs such as brown and blonde hair are particularly prone to hue differences relative to the green resist region, the method is configured to detect first hairs by utilizing hue difference. Therefore, first hairs such as brown and blonde hair located in the resist region can be detected with high precision.

[0017] Furthermore, according to Scheme 1 above, in at least the resist region of the chroma image, hairs containing at least black and / or white hair can be detected as second hairs by utilizing the chroma difference with the resist region. That is, considering that second hairs such as black and white hair are particularly prone to chroma differences relative to the green resist region, the detection of second hairs is configured to utilize chroma differences. Therefore, second hairs such as black and white hair located in the resist region can be detected with high precision. Thus, according to Scheme 1 above, hairs of commonly common colors such as black, white, brown, or blonde hair can be detected with high precision.

[0018] Furthermore, hair detection is performed using only hue and chroma images, without using a brightness image of the substrate being inspected. Therefore, it is possible to more reliably prevent the misdetection of circuit patterns, height differences, and damage as hair, which often occurs when using brightness images. Moreover, since brightness images are not used, the workload associated with the inspection process can be further reduced.

[0019] Furthermore, as mentioned above, since false detections caused by circuit patterns, height differences, etc., can be prevented, there is no need for the cumbersome process of excluding areas containing circuit patterns from the inspection target to prevent false detections. This further reduces the processing burden related to inspection, enables high-speed inspection, and suppresses the increase in inspection-related costs.

[0020] Solution 2. The hair inspection device for the substrate according to Solution 1, characterized in that, It includes a resist area information acquisition unit to acquire resist area information for determining the range occupied by the resist area in the substrate under inspection. The first hair detection unit and the second hair detection unit are configured to detect the first hair and the second hair, at least the resist area determined by the resist area information obtained by the resist area information acquisition unit.

[0021] According to Scheme 2 above, the presence or absence of hair can be selectively checked in the resist area. Therefore, the risk caused by carbonization of hair located in the resist area can be more reliably avoided.

[0022] Solution 3. The hair inspection device for a substrate according to Solution 2, characterized in that the resist area information acquisition unit is configured to acquire the resist area information based on the design information and / or manufacturing information of the printed substrate.

[0023] In addition, as design information, CAD data of the printed circuit board can be provided, and as manufacturing information, Gerber data of the printed circuit board can be provided.

[0024] According to the above scheme 3, design information and manufacturing information can be used to easily obtain sufficiently accurate resist area information based on the relationship with the substrate being inspected.

[0025] Solution 4. The hair inspection device for the substrate according to Solution 2, characterized in that, It includes a main color image acquisition unit that uses multiple colored lights to acquire a main color image related to a main substrate, wherein the main substrate is ideally the printed substrate. The resist area information acquisition unit is configured to obtain the resist area information by using the main color image to obtain a hue image of the main substrate and extracting a region from the hue image that matches the hue of the resist area, and / or using the main color image to obtain a chroma image of the main substrate and extracting a region from the chroma image that matches the chroma of the resist area.

[0026] According to Scheme 4 above, resist area information is obtained using the main substrate. Therefore, sufficiently accurate resist area information can be obtained based on its relationship with the substrate being inspected without using design or manufacturing information.

[0027] Furthermore, when attempting to obtain resist area information by extracting regions with the same brightness as the resist area from a brightness image, it's possible to misidentify circuit patterns or height differences located in areas overlapping with the resist area as non-resist regions. Regarding this, in the aforementioned solution 4, resist area information is obtained by extracting regions with the same hue and chroma as the resist area from a hue image and a chroma image. This allows for more accurate identification of the resist area in the main substrate, resulting in more accurate resist area information. Consequently, the inspection of the resist area on the substrate under inspection can be performed more appropriately.

[0028] Solution 5. The hair inspection apparatus for a substrate according to Solution 2, characterized in that the resist area information acquisition unit is configured to acquire the resist area information by extracting a region with the same hue as the resist area from the hue image of the substrate under inspection, and / or extracting a region with the same chroma as the resist area from the chroma image of the substrate under inspection.

[0029] According to Scheme 5, similar to Scheme 4, it can more reliably prevent the misclassification of elevation differences, damage, etc., located at positions overlapping with the resist area as non-resist areas. Therefore, the resist area can be determined more accurately, thereby obtaining more accurate resist area information.

[0030] Furthermore, according to Scheme 5 above, since the resist area information is obtained based on an image of the substrate being inspected, the area based on the obtained resist area information more accurately matches the actual resist area in the substrate being inspected, thus enabling the acquisition of optimal resist area information for the substrate being inspected. Therefore, hair inspection targeting the resist area of ​​the substrate being inspected can be performed with higher precision.

[0031] Solution 6. A method for inspecting hair on a substrate, for a printed circuit board having a green resist area and a solder paste printed thereon, inspecting at least the resist area for hair, characterized in that it includes: The color image acquisition process uses multiple colored lights to acquire a color image related to the substrate being inspected, which is the printed substrate that is the object of inspection. The hue image acquisition process uses the color image to obtain the hue image of the substrate under inspection; The chroma image acquisition process uses the color image to obtain a chroma image of the substrate under inspection; In the first hair detection step, hairs comprising at least brown and / or blonde hair are detected as first hairs in at least the resist region of the hue image using hue difference relative to the resist region; and In the second hair detection step, in at least the resist region of the chroma image, hairs containing at least black and / or white hair can be detected as second hairs using the chroma difference relative to the resist region. In the first hair detection process, the detection of the first hair is performed based solely on the hue image, without using the brightness image of the substrate being inspected. In the second hair detection process, the detection of the second hair is performed based solely on the chroma image, without using the brightness image of the substrate being inspected.

[0032] According to the above scheme 6, it achieves the same effect as the above scheme 1.

[0033] Solution 7. The method for inspecting hair on a substrate according to Solution 6, characterized in that, This includes a resist area information acquisition step, which acquires resist area information used to determine the extent of the resist area in the substrate being inspected. In the first hair detection step and the second hair detection step, at least the resist area determined by the resist area information obtained in the resist area information acquisition step is used as the inspection object for the detection processing of the first hair and the second hair.

[0034] According to Scheme 7 above, it achieves the same effect as Scheme 2 above. Attached Figure Description

[0035] Figure 1 This is a top view schematic diagram showing the general structure of a printed circuit board.

[0036] Figure 2 This is a magnified cross-sectional view of a printed circuit board.

[0037] Figure 3 This is a block diagram showing the structure of a printed circuit board production line.

[0038] Figure 4This is a schematic diagram showing the general structure of a solder printing post-inspection device.

[0039] Figure 5 This is a block diagram showing the functional structure of the solder printing post-inspection device.

[0040] Figure 6 It is a simplified diagram representing the color wheel of the HSV color space.

[0041] Figure 7 It is a diagram showing the hue image associated with the inspected substrate with gold pigment attached.

[0042] Figure 8 It is a diagram showing the hue image associated with the inspected substrate with attached brown hair.

[0043] Figure 9 It is a graph representing the chroma image associated with the inspected substrate with attached black hair.

[0044] Figure 10 It is a graph representing a chroma image related to the inspected substrate with attached white hair. Detailed Implementation

[0045] Hereinafter, one embodiment will be described with reference to the accompanying drawings. First, the structure of the printed circuit board 1 will be described.

[0046] like Figure 1 , Figure 2 As shown, the printed circuit board 1 is a substrate formed on a flat substrate 2 made of glass epoxy resin or the like, on which a circuit pattern 3a made of copper foil and pads 3b are formed, and through holes 3c of the pads 3b are provided through the pads 3b on the surface and back of the substrate 2. A paste solder 5 formed by stirring solder particles with flux is printed on the pads 3b and the through holes 3c. For example, the electrode part of a specified component (e.g., an electronic component) not shown is electrically connected to the pads 3b via the paste solder 5.

[0047] Additionally, a green resist area 4 is provided on the surface of the substrate 2, excluding the pad 3b. Figure 1 (The area with an added scattered pattern). The resist area 4 is made of insulating resist and is coated with the substrate 2 and the circuit pattern 3a. In addition, sometimes there is a height difference caused by the circuit pattern 3a, etc., on the upper surface of the resist area 4 and below the resist area 4.

[0048] Next, refer to Figure 3 The production line (manufacturing process) for manufacturing printed circuit board 1 is described. For example... Figure 3 As shown, in production line 10, from its upstream side ( Figure 3Starting from the top, a solder printing machine 12, a solder printing post-inspection device 13, a component mounting machine 14, a reflow device 15, and a reflow post-inspection device 16 are arranged sequentially. The printed circuit board 1 is configured to be transported relative to these devices in the aforementioned order. In this embodiment, the solder printing post-inspection device 13 constitutes a "substrate hair inspection device".

[0049] The solder printing machine 12 performs a solder printing process to print paste solder 5 onto each pad 3b of the printed circuit board 1. For example, the paste solder 5 is printed by screen printing. In screen printing, firstly, with the lower surface of the screen mask in contact with the printed circuit board 1, paste solder 5 is supplied to the upper surface of the screen mask. A plurality of openings corresponding to each pad 3b of the printed circuit board 1 are formed on the screen mask. Next, a predetermined squeegee is brought into contact with and moved against the upper surface of the screen mask, thereby filling the openings with paste solder 5. Afterward, by separating the printed circuit board 1 from the lower surface of the screen mask, paste solder 5 is applied to the pads 3b and filled into the through holes 3c.

[0050] The solder printing post-inspection apparatus 13 performs a solder printing post-inspection process, which checks the state of the printed solder paste 5 and whether there are any foreign objects on the printed substrate 1 on which the solder paste 5 is printed. In addition, during the solder printing post-inspection process, the printed substrate 1 on which the solder paste 5 is printed is inspected at least for the presence of hair in the resist area 4. The solder printing post-inspection apparatus 13 will be described in more detail later.

[0051] The component mounting machine 14 performs a component mounting process (mounting process) on the pads 3b, etc., on which the component is printed with solder paste 5. As a result, the electrode portions of the component are temporarily fixed to the specified solder paste 5.

[0052] The reflow apparatus 15 performs a reflow process in which the paste solder 5 is heated and melted to bond (brazing) the pad 3b to the electrode portion of the component.

[0053] The reflow inspection apparatus 16 performs a reflow inspection process, in which it checks whether the solder bonding was properly performed during the reflow process. For example, it uses image data of the printed circuit board 1 after the reflow process to check whether the components have positional misalignment.

[0054] Thus, in production line 10, printed circuit board 1 is conveyed sequentially, and solder printing process → solder printing inspection process → component installation process (installation process) → reflow process → reflow inspection process.

[0055] In addition, although illustration is omitted, the production line 10 is provided with conveyors and the like for transferring the printed circuit board 1 between the respective devices, such as between the solder printer 12 and the post-solder-printing inspection device 13. Further, a branching device is provided between the post-solder-printing inspection device 13 and the component mounter 14, and on the downstream side of the post-reflow inspection device 16. Then, the printed circuit board 1 determined as a non-defective product by the post-solder-printing inspection device 13 and the post-reflow inspection device 16 is guided directly to the downstream side, while the printed circuit board 1 determined as a defective product by the inspection devices 13 and 16 is discharged by the branching device to a defective product storage unit (not illustrated).

[0056] Next, the configuration of the post-solder-printing inspection device 13 will be described. As shown in Figure 4 , Figure 5 , the post-solder-printing inspection device 13 is provided with: a transport mechanism 31 that performs transport, positioning and the like of the printed circuit board 1; an inspection unit 32 that is used for inspecting the printed circuit board 1; and a control device 33 that executes various controls, image processing, and arithmetic processing in the post-solder-printing inspection device 13, starting with drive control of the transport mechanism 31 and the inspection unit 32.

[0057] The transport mechanism 31 is provided with a pair of transport rails 31a arranged along the loading and unloading direction of the printed circuit board 1, and an endless belt 31b rotatably disposed relative to each of the transport rails 31a. In addition, although illustration is omitted, the transport mechanism 31 is provided with a drive unit such as a motor for driving the belt 31b, and a chuck mechanism for positioning the printed circuit board 1 at a predetermined position. The transport mechanism 31 is drive-controlled by the control device 33 (a transport mechanism control unit 341 to be described later).

[0058] With the above configuration, both side edges in the width direction orthogonal to the loading and unloading direction of the printed circuit board 1 carried into the post-solder-printing inspection device 13 are inserted into the transport rails 31a, and the printed circuit board 1 is placed on the belts 31b. Next, the belts 31b start operating to transport the printed circuit board 1 to a predetermined inspection position. When the printed circuit board 1 reaches the inspection position, the belts 31b stop, and the chuck mechanism operates. Through the operation of the chuck mechanism, the belts 31b are pushed up, bringing about a state where both side edges of the printed circuit board 1 are held between the belts 31b and the upper edge portions of the transport rails 31a. Thereby, the printed circuit board 1 is positioned and fixed at the inspection position. When the inspection is finished, the fixation by the chuck mechanism is released, and the belts 31b start operating. Thereby, the printed circuit board 1 is unloaded from the post-solder-printing inspection device 13. Naturally, the configuration of the transport mechanism 31 is not limited to the above-described mode, and other configurations may also be adopted.

[0059] The inspection unit 32 is disposed above the transport guide rail 31a (the transport path of the printed circuit board 1). The inspection unit 32 includes an illumination device 321 and a camera 322. Additionally, the inspection unit 32 is equipped with a camera capable of performing X-axis direction (…). Figure 4 The X-axis moving mechanism 323, capable of moving in the left and right directions, and capable of moving in the Y-axis direction ( Figure 4 The Y-axis moving mechanism 324 moves in the forward and backward direction. The two moving mechanisms 323 and 324 are driven and controlled by the control device 33 (moving mechanism control unit 340 described later). In this embodiment, the lighting device 321 and the camera 322 constitute a "color image acquisition unit".

[0060] The lighting device 321 illuminates a predetermined light onto the printed circuit board 1 (hereinafter referred to as "the board to be inspected"). This board is the object of inspection by the solder printing post-inspection device 13. More specifically, the lighting device 321 includes a first ring lamp 321a, a second ring lamp 321b, and a third ring lamp 321c (see reference 1). Figure 4 ).

[0061] The first ring lamp 321a illuminates the substrate 1a to be inspected from a generally horizontal direction. The second ring lamp 321b is positioned above the first ring lamp 321a and illuminates the substrate 1a to be inspected from an obliquely upward position. The third ring lamp 321c is positioned inside the second ring lamp 321b and illuminates the substrate 1a to be inspected from a generally vertical position.

[0062] Each ring lamp 321a, 321b, and 321c irradiates white light onto the substrate 1a under inspection. That is, each ring lamp 321a, 321b, and 321c irradiates multiple colored lights, such as red, blue, and green light, onto the substrate 1a under inspection at one time.

[0063] The camera 322 is configured such that its optical axis is along the vertical direction (Z-axis direction) to capture images of a predetermined area to be inspected in the substrate 1a from directly above. In addition, the "inspected area" of the substrate 1a is one of a plurality of areas pre-defined on the substrate 1a, with the size of the camera 322's field of view (shooting range) as 1 unit.

[0064] Camera 322 is a color camera, and its operation is controlled by control device 33 (camera control unit 333 described later). Under the control of control device 33 (camera control unit 333), camera 322 captures the reflected light from the substrate 1a being inspected while it is simultaneously illuminated by ring lights 321a, 321b, and 321c. This acquires a color image related to the inspected area of ​​substrate 1a. This color image includes at least an image of the resist area 4. Furthermore, this color image has multiple pixels, and three parameter values ​​related to R (red), G (green), and B (blue) are set for each pixel. In this embodiment, these parameter values ​​are represented in the range of 0 to 1.

[0065] The color image captured by camera 322 is transmitted to control device 33 (color image acquisition unit 334 described later). Then, control device 33 performs inspection processing based on the color image. In this embodiment, the process of acquiring a color image by camera 322 while the substrate 1a under inspection is illuminated by illumination device 321 is equivalent to a "color image acquisition process".

[0066] The control device 33 is a computer consisting of a CPU (Central Processing Unit) that performs prescribed arithmetic operations, a ROM (Read Only Memory) that stores various programs and fixed-value data, a RAM (Random Access Memory) that temporarily stores various data during the execution of various arithmetic operations, and their peripheral circuits.

[0067] The control device 33 operates according to various programs via the CPU, functioning as a main control unit 331, an illumination control unit 332, a camera control unit 333, a color image acquisition unit 334, a hue image acquisition unit 335, a chroma image acquisition unit 336, a resist area information acquisition unit 337, a first hair detection unit 338, a second hair detection unit 339, a moving mechanism control unit 340, and a conveying mechanism control unit 341. In this embodiment, the hue image acquisition unit 335 constitutes a "hue image acquisition unit," similarly, the chroma image acquisition unit 336 constitutes a "chroma image acquisition unit," the resist area information acquisition unit 337 constitutes a "resist area information acquisition unit," the first hair detection unit 338 constitutes a "first hair detection unit," and the second hair detection unit 339 constitutes a "second hair detection unit."

[0068] However, the various functional units are implemented through the cooperation of various hardware components such as the CPU, ROM, and RAM. It is not necessary to explicitly distinguish between functions implemented by hardware or software. Some or all of these functions can also be implemented by hardware circuits such as ICs. In addition, the control device 33 has a functional unit for checking the state of the solder paste 5 and whether there are foreign objects in the printed circuit board 1, but this functional unit is omitted in this embodiment.

[0069] Furthermore, the control device 33 is equipped with an input unit 342 consisting of a keyboard, mouse, touch panel, etc.; a display unit 343 consisting of an LCD display and other components capable of displaying images; a storage unit 344 capable of storing various data, programs, calculation results, check results, etc.; and a communication unit 345 capable of sending and receiving various data with external devices. First, the storage unit 344 and the communication unit 345 will be explained.

[0070] The storage unit 344 is composed of HDD (Hard Disk Drive), SSD (Solid State Drive), etc., and stores various information. The storage unit 344 includes an image storage unit 344a, an inspection information storage unit 344b, a resist area information storage unit 344c, and an inspection result storage unit 344d.

[0071] Image storage unit 344a stores color images captured by camera 322. Additionally, image storage unit 344a also stores hue images and chroma images (described later) acquired by hue image acquisition unit 335 or chroma image acquisition unit 336. The color images, hue images, and chroma images stored in image storage unit 344a can be appropriately displayed on display unit 343.

[0072] The inspection information storage unit 344b stores various information for inspecting the substrate 1a. For example, the inspection information storage unit 344b stores thresholds for binarizing hue images (hue threshold), thresholds for binarizing chroma images (chroma threshold), and reference values ​​for determining whether a region is resist region 4 (region determination reference value). In addition, the inspection information storage unit 344b also stores area thresholds and length thresholds for determining whether a region is hair.

[0073] The resist area information storage unit 344c stores the resist area information acquired by the resist area information acquisition unit 337.

[0074] The inspection result storage unit 344d stores the inspection result data of the hair detection units 338 and 339. In addition, the inspection result storage unit 344d also stores inspection result data related to the state of the solder paste 5, the presence of foreign matter on the printed circuit board 1, and statistical data that has undergone probability statistical processing of various inspection result data. This inspection result data and statistical data can be appropriately displayed on the display unit 343.

[0075] The communication unit 345 is equipped with a wireless communication interface based on communication standards such as wired LAN (Local Area Network) or wireless LAN, and is configured to send and receive various data with external devices. For example, the communication unit 345 can output the inspection results performed by the hair detection units 338 and 339 to the outside, or it can input the inspection results performed by the return inspection device 16.

[0076] Next, the various functional units constituting the control device 33 will be described in detail. First, the moving mechanism control unit 340 and the conveying mechanism control unit 341 will be described, and then the main control unit 331 and the like will be described.

[0077] The movement mechanism control unit 340 is a functional unit that drives and controls the X-axis movement mechanism 323 and the Y-axis movement mechanism 324, and controls the position of the inspection unit 32 based on the command signal from the main control unit 331. By driving and controlling the X-axis movement mechanism 323 and the Y-axis movement mechanism 324, the movement mechanism control unit 340 can move the inspection unit 32 to a position above any inspected area in the substrate 1a that is fixed at the inspection position. Then, while moving the inspection unit 32 sequentially to multiple inspected areas set on the substrate 1a, inspections related to those inspected areas are performed, thereby performing an inspection of the entire area of ​​the substrate 1a.

[0078] The conveying mechanism control unit 341 is a functional unit that drives and controls the conveying mechanism 31, and controls the conveying position of the substrate 1a to be inspected based on the command signal from the main control unit 331.

[0079] Next, the main control unit 331 will be explained. The main control unit 331 is a functional unit responsible for the overall control of the solder printing post-inspection device 13, and is configured to receive and send various signals with other functional units such as the lighting control unit 332 and the camera control unit 333.

[0080] The lighting control unit 332 is a functional unit that drives and controls the lighting device 321. The lighting control unit 332 performs timing control and other functions related to the illumination or cessation of illumination of the substrate 1a under inspection by the lighting device 321 based on the command signals from the main control unit 331.

[0081] The camera control unit 333 is a functional unit that drives and controls the camera 322. The camera control unit 333 controls the timing of the camera 322's shooting of the substrate 1a under inspection based on the command signals from the main control unit 331.

[0082] The color image acquisition unit 334 is a functional unit for acquiring color images captured by the camera 322. The color images acquired by the color image acquisition unit 334 are stored in the image storage unit 344a.

[0083] The hue image acquisition unit 335 uses a color image stored in the image storage unit 344a that is related to the inspected area of ​​the inspected substrate 1a to acquire a hue image related to the inspected area of ​​the inspected substrate 1a. The hue image is an image that represents the hue of each pixel in the color image in the hue circle of the HSV color space. Figure 7 , Figure 8 This represents an example of a hue image. The hue image acquisition unit 335 calculates the hue wheel of the HSV color space with 0° (360°) set to red, 60° set to yellow, 120° set to (strictly) green, 180° set to cyan, 240° set to blue, and 300° set to magenta (see reference). Figure 6 The image storage unit 335 acquires the hue (hereinafter referred to as "hue H") of each pixel in the image storage unit 344a, and obtains a hue image by associating each pixel with its hue H. In this embodiment, the process of obtaining the hue image of the substrate 1a under inspection by the hue image acquisition unit 335 is equivalent to a "hue image acquisition process". The hue image is stored in the image storage unit 344a.

[0084] Hue H is calculated using the following mathematical formula 1, mathematical formula 2, or mathematical formula 3. Formula 1 is used when the value of parameter B among the RGB-related parameters is the largest. Formula 2 is used when the value of parameter R among the RGB-related parameters is the largest. Formula 3 is used when the value of parameter G among the RGB-related parameters is the largest. However, hue H is not defined if the maximum and minimum values ​​of the RGB-related parameters are equal.

[0085] <Mathematical Formula 1> H = 60 × (GR) / (MAX - MIN) + 60 <Mathematical Formula 2> H = 60 × (BG) / (MAX - MIN) + 180 <Mathematical Formula 3> H = 60 × (RB) / (MAX - MIN) + 300 In addition, in mathematical formulas 1 to 3, R, G, and B represent the parameter values ​​related to RGB, MAX represents the maximum value among the parameter values, and MIN represents the minimum value among the parameter values.

[0086] The chroma image acquisition unit 336 uses a color image stored in the image storage unit 344a that is related to the inspected area of ​​the inspected substrate 1a to acquire a chroma image related to the inspected area of ​​the inspected substrate 1a. A chroma image is an image that represents the chroma of each pixel in a color image. Figure 9 , Figure 10 This is an example of a chroma image. The chroma image acquisition unit 336 uses the following mathematical formula 4 to calculate the chroma S (chroma in HSV form) of each pixel in the color image, and acquires a chroma image formed by associating each pixel with the chroma S. In this embodiment, the process of obtaining the chroma image of the substrate 1a under inspection by the chroma image acquisition unit 336 is equivalent to a "chroma image acquisition process". The chroma image is stored in the image storage unit 344a.

[0087] <Mathematical Expression 4> S = (1 - 3 × MIN / (R + G + B)) Furthermore, similar to mathematical formulas 1 through 3, in mathematical formula 4, R, G, and B represent the parameter values ​​related to RGB, and MIN represents the minimum value among these parameter values. Additionally, the chroma S of each pixel in a chroma image is represented by values ​​from 0 to 1; the closer the chroma S of a pixel is to 1, the closer its color is to the primary color. Alternatively, the chroma S can be calculated using mathematical formula 4a below, instead of mathematical formula 4.

[0088] <Mathematical Formula 4a> S = (MAX - MIN) / MAX The resist area information acquisition unit 337 acquires resist area information for determining the range occupied by the resist area 4 in the substrate 1a to be inspected. In this embodiment, the resist area information acquisition unit 337 acquires the resist area information based on the printed circuit board 1 to be inspected, i.e., the substrate 1a to be inspected.

[0089] More specifically, the resist area information acquisition unit 337 acquires the same hue image as described above based on the color image. Alternatively, the hue image acquired by the hue image acquisition unit 335 may also be used.

[0090] Next, the resist area information acquisition unit 337 processes the connection components of pixels whose hue H in the hue image falls within a specified range (in this embodiment, for example, 70° or more and 160° or less), and calculates the area (in this embodiment, the number of pixels) of the determined connection components (block portions). That is, the resist area information acquisition unit 337 calculates the area of ​​block portions in the color image that are green or close to green.

[0091] Based on this, the resist area information acquisition unit 337 compares the area of ​​the block portion with the area determination reference value pre-stored in the inspection information storage unit 344b, and determines the block portion whose area exceeds the area determination reference value as resist area 4. Then, the resist area information acquisition unit 337 acquires information used to determine the resist area 4 (e.g., coordinate information indicating the position of the resist area 4) as resist area information. The acquired resist area information is stored in the resist area information storage unit 344c. In this embodiment, the process of acquiring resist area information by the resist area information acquisition unit 337 is equivalent to a "resist area information acquisition process".

[0092] The first hair detection unit 338 detects hairs, including at least brown and blonde hairs, as first hairs in at least the resist region 4 of the hue image acquired by the hue image acquisition unit 335, using the hue difference relative to the resist region 4. Here, the method for detecting the first hairs will be described in detail.

[0093] First, the first hair detection unit 338 obtains a binarized hue image obtained by binarizing each pixel of the hue image using hue components. In this embodiment, the binarized hue image is obtained by comparing a hue threshold pre-stored in the inspection information storage unit 344b with the hue H of each pixel in the hue image, thereby binarizing each pixel in the hue image. The resulting binarized hue image becomes a black and white image having 0 (bright portion) and 1 (dark portion). The binarized hue image is stored in the image storage unit 344a.

[0094] Additionally, for reference, a hue image related to the inspected substrate 1a with the attached blonde X1 is shown (see reference). Figure 7 ) and a hue image related to the inspected substrate 1a with attached brown hair X2 (see reference) Figure 8 As shown above, in the hue image, the hues of blonde X1 and brown X2 are sufficiently different from the hue of resist region 4 for inspection. Therefore, in the binarized hue image, for example, blonde X1 and brown X2 are represented by dark areas, and resist region 4 is represented by light areas.

[0095] After obtaining the binarized hue image, the first hair detection unit 338 sets at least the resist region 4 determined from the resist region information obtained by the resist region information acquisition unit 337 in the binarized hue image as the inspection target (inspection range). Therefore, pads 3b, vias 3c, text portions, graphic portions, etc. attached to the substrate 1a being inspected are removed from the inspection target (inspection range). In addition, in this embodiment, since the resist region information and the hue image are obtained based on the same substrate 1a being inspected, the inspection target optimal for that substrate 1a is set.

[0096] Based on this, the first hair detection unit 338 performs a process in the inspected object (inspection range) to determine the connection components of pixels (e.g., dark areas) that have a hue different from that of the resist region 4 (e.g., the bright area), and calculates the area (e.g., number of pixels) of the determined connection components (block portions). In addition, the first hair detection unit 338 calculates the length (e.g., X-direction length and Y-direction length) of the connection components (block portions).

[0097] Next, the first hair detection unit 338 compares the area of ​​the block portion with an area threshold pre-stored in the inspection information storage unit 344b. If the area of ​​the block portion exceeds the area threshold, the first hair detection unit 338 determines that a first hair is present in the resist region 4 and classifies the inspected area in the substrate 1a under inspection as "unqualified".

[0098] Furthermore, the first hair detection unit 338 compares the length of the block portion with a length threshold pre-stored in the inspection information storage unit 344b. If the length of the block portion exceeds the length threshold, the first hair detection unit 338 determines that a first hair is present in the resist region 4 and classifies the inspected area in the substrate 1a under inspection as "unqualified".

[0099] Alternatively, the first hair detection unit 338 can determine that a first hair exists in the resist region 4 if the area of ​​the block portion exceeds the area threshold and the length of the block portion exceeds the length threshold. Alternatively, parameters other than area and length (e.g., thickness, shape) can be used to determine the presence of a first hair.

[0100] On the other hand, if the area of ​​the block portion is below the area threshold and the length of the block portion is below the length threshold, the first hair detection unit 338 determines that no first hair exists in the resist region 4. Then, the first hair detection unit 338 determines the inspected area in the inspected substrate 1a as "qualified". In this embodiment, the process of detecting the first hair by the first hair detection unit 338 is equivalent to the "first hair detection process".

[0101] Then, the first hair detection unit 338 performs the inspection process related to the presence or absence of first hair on the entire inspected area of ​​the substrate 1a. That is, the first hair detection unit 338 performs the inspection process using all hue images related to the substrate 1a. The inspection results related to the first hair in the entire inspected area are stored in the inspection result storage unit 344d. In this way, the first hair detection unit 338 does not use the brightness image of the substrate 1a (an image representing the brightness of each pixel of the substrate 1a), but only performs the first hair detection process based on the hue image of the substrate 1a.

[0102] The second hair detection unit 339 detects hairs, including at least black and white hairs, as second hairs in at least the resist region 4 of the chroma image acquired by the chroma image acquisition unit 336, using the chroma difference relative to the resist region 4. The method for detecting second hairs will be described in more detail here.

[0103] First, the second hair detection unit 339 obtains a binarized chroma image obtained by binarizing each pixel of the chroma image using chroma components. In this embodiment, the binarized chroma image is obtained by comparing a chroma image acquisition threshold pre-stored in the inspection information storage unit 344b with the chroma S of each pixel in the chroma image, and then binarizing each pixel in the chroma image. The obtained binarized chroma image is a black and white image with 0 (dark parts) and 1 (bright parts). The binarized chroma image is stored in the image storage unit 344a.

[0104] Additionally, for reference, a chroma image related to the inspected substrate 1a with attached black hair X3 is shown (see reference). Figure 9 ) and the chroma image related to the inspected substrate 1a with attached white hair X4 (see reference) Figure 10 As shown above, in the chroma image, the chroma values ​​of black hair X3 and white hair X4 are sufficiently different from the chroma value of the resist region 4 for inspection. Therefore, in the binarized chroma image, for example, black hair X3 and white hair X4 are represented by dark areas, and the resist region 4 is represented by bright areas.

[0105] After obtaining the binarized chroma image, the second hair detection unit 339 sets the resist region 4 in the binarized chroma image, which is determined by the resist region information obtained by the resist region information acquisition unit 337, as the inspection object (inspection range).

[0106] Based on this, the second hair detection unit 339 performs processing in the inspection object (inspection range) to determine the connection components of pixels (e.g., dark parts) that have different chroma from the resist region 4 (e.g., bright parts), and calculates the area and length of the determined connection components (block parts).

[0107] Next, the second hair detection unit 339 compares the area of ​​the block portion with the area threshold. If the area of ​​the block portion exceeds the area threshold, it determines that a second hair is present in the resist region 4. Additionally, the second hair detection unit 339 compares the length of the block portion with the length threshold. If the length of the block portion exceeds the length threshold, it determines that a second hair is present in the resist region 4. Furthermore, when the second hair detection unit 339 determines that a second hair is present in the resist region 4, it classifies the inspected area of ​​the inspected substrate 1a as "unqualified".

[0108] Additionally, the second hair detection unit 339 can also determine the presence of a second hair in the resist region 4 if the area of ​​the block portion exceeds the area threshold and the length of the block portion exceeds the length threshold. Alternatively, parameters other than area and length (such as thickness, shape, etc.) can be used to determine the presence of a second hair.

[0109] On the other hand, if the area of ​​the block portion is below the area threshold and the length of the block portion is below the length threshold, the second hair detection unit 339 determines that there is no second hair in the resist region 4 and determines the inspected area in the inspected substrate 1a as "qualified". In this embodiment, the process of detecting the second hair by the second hair detection unit 339 is equivalent to the "second hair detection process".

[0110] Then, the second hair detection unit 339 performs the inspection process related to the presence or absence of second hair on the entire inspected area of ​​the substrate 1a. That is, the second hair detection unit 339 performs the inspection process using the entire chroma image related to the substrate 1a. The inspection results related to the second hair in the entire inspected area are stored in the inspection result storage unit 344d. In this way, the second hair detection unit 339 does not use the brightness image of the substrate 1a, but only performs the second hair detection process based on the chroma image of the substrate 1a.

[0111] In addition, the solder printing inspection device 13 (main control unit 331) performs an inspection on all inspected areas of the inspected substrate 1a related to the presence or absence of the first hair and the second hair. As a result, if all inspected areas are determined to be "qualified", it determines that there is no hair in the resist area 4 of the inspected substrate 1a and stores the determination result in the inspection result storage unit 344d.

[0112] On the other hand, even if there is an area that is determined to be "unqualified" during the solder printing inspection, the solder printing inspection device 13 determines that there is hair (i.e., a defective part) on the inspected substrate 1a and stores the determination result in the inspection result storage unit 344d. In addition, such determination results are notified to the outside via the display unit 343, the communication unit 345, etc.

[0113] As detailed above, according to this embodiment, in at least the resist region 4 of the hue image, hairs including at least brown and blonde hair can be detected as first hairs by utilizing the hue difference with the resist region 4. That is, considering that first hairs such as brown and blonde hair are particularly prone to hue differences relative to the green resist region 4, the method is configured to detect first hairs using hue difference. Therefore, first hairs such as brown and blonde hair located in the resist region 4 can be detected with high precision.

[0114] Furthermore, within at least the resist region 4 of the chroma image, hairs containing at least black and white hair can be detected as second hairs by utilizing the chroma difference with the resist region 4. That is, considering that second hairs such as black and white hair are particularly prone to chroma differences relative to the green resist region 4, the method is configured to detect second hairs using chroma differences. Therefore, second hairs such as black and white hair located in the resist region 4 can be detected with high precision.

[0115] Thus, according to this embodiment, the first and second hairs can be detected with high precision. That is, hairs of common colors such as black, white, brown, or blonde can be detected with high precision.

[0116] Furthermore, instead of using a brightness image of the substrate 1a under inspection, only hue and chroma images are used to detect individual hairs. Therefore, it is possible to more reliably prevent the misdetection of circuit patterns 3a, height differences, and damage as hairs, which often occur when using brightness images. Moreover, since brightness images are not used, the burden associated with the inspection process can be further reduced.

[0117] Furthermore, as described above, false detections caused by circuit pattern 3a, height differences, etc., can be prevented, thus eliminating the need for cumbersome procedures such as excluding areas containing circuit pattern 3a from the inspection target to prevent false detections. This further reduces the processing burden related to inspection, enabling high-speed inspection and suppressing increases in inspection-related costs.

[0118] Furthermore, the two hair detection units 338 and 339 are configured to detect at least the first hair and the second hair, taking the resist region 4 determined by the resist region information obtained by the resist region information acquisition unit 337 as the inspection target. Therefore, the presence or absence of hair can be selectively inspected in the resist region 4. As a result, the risk caused by carbonization of hair located in the resist region 4 can be avoided more reliably.

[0119] Furthermore, by extracting the region whose hue matches that of the resist region 4 from the hue image of the substrate 1a under inspection, resist region information can be obtained. Therefore, compared to using the brightness image of the substrate 1a under inspection, it is more reliable to prevent misidentification of areas such as height differences or damage located where the resist region 4 overlaps with the resist region 4 as non-resist regions. Thus, the resist region 4 can be determined more accurately, and more accurate resist region information can be obtained.

[0120] Furthermore, since the resist area information is obtained based on an image of the substrate 1a under inspection, the area based on the obtained resist area information more accurately matches the actual resist area 4 in the substrate 1a under inspection, enabling the acquisition of optimal resist area information for the substrate 1a under inspection. Therefore, hair inspection targeting the resist area 4 of the substrate 1a under inspection can be performed with higher precision.

[0121] Furthermore, the implementation is not limited to the content described in the embodiments described above; for example, it can also be implemented as follows. Of course, other application examples and modifications not illustrated below are also possible.

[0122] (a) In the described embodiment, the resist area information acquisition unit 337 is configured to acquire resist area information by extracting a portion of a certain range of hue from a hue image related to the substrate 1a being inspected as the resist area. Alternatively, the resist area information acquisition unit 337 can also acquire resist area information by extracting a portion of a certain range of chroma from a chroma image as the resist area. Of course, both methods for acquiring resist area information can be used.

[0123] (b) In the embodiment described above, the resist area information acquisition unit 337 is configured to acquire resist area information based on an image of the substrate 1a being inspected.

[0124] In contrast, the resist area information acquisition unit 337 can also acquire resist area information by at least one of the following methods: obtaining a hue image of the main substrate using a main color image and extracting areas from the hue image that match the hue of the resist area; or obtaining a chroma image of the main substrate using a main color image and extracting areas from the chroma image that match the chroma of the resist area. The main color image is a color image of the main substrate (not shown), which is ideally the printed circuit board 1. The main color image can be acquired, for example, by taking a picture with a camera 322 while the main substrate supplied to the solder printing post-inspection device 13 is illuminated by an illumination device 321. In this case, the illumination device 321 and the camera 322 constitute a "main color image acquisition unit".

[0125] By configuring the resist area information to be obtained based on the main color image, sufficiently accurate resist area information can be obtained based on its relationship with the substrate 1a being inspected without using the design information and manufacturing information described later.

[0126] Furthermore, since the resist region information is obtained by extracting regions with the same hue and chroma as the resist region from the hue and chroma images, the resist region 4 in the main substrate can be determined more accurately compared to using a brightness image, thus obtaining more accurate resist region information. As a result, the resist region 4 of the substrate 1a under inspection can be inspected more appropriately.

[0127] (c) The resist area information acquisition unit 337 can also acquire resist area information based on at least one of the design information and manufacturing information of the printed circuit board 1. As design information, CAD data of the printed circuit board 1 can be cited, and as manufacturing information, Gerber data of the printed circuit board 1 can be cited.

[0128] By using design and manufacturing information to obtain resist area information, even when the printed circuit board 1, main board, etc. are not readily available, sufficiently accurate resist area information can be easily obtained based on the relationship with the substrate 1a being inspected.

[0129] (d) In the described embodiment, each of the ring lights 321a, 321b, and 321c is configured to illuminate white light, but it can also illuminate red, blue, or green light (i.e., different colors). Alternatively, in this case, a monochrome camera 322 can be configured to capture images of the printed circuit board 1 each time the images are sequentially illuminated by each of the ring lights 321a, 321b, and 321c, resulting in a total of three images. Furthermore, a hue image and a chroma image can be obtained based on these three images. Additionally, parameter values ​​related to R (red), G (green), or B (blue) are respectively set for each pixel in each of the three images. Therefore, these three images can be considered equivalent to "color images."

[0130] (e) In the described embodiment, when detecting the first hair and the second hair, the hue image and chroma image are binarized to obtain a binarized hue image and a binarized chroma image, but obtaining the binarized images is not necessarily required. Therefore, for example, the hue image and chroma image can be used directly to detect the first hair and the second hair. For example, the configuration can be such that the area and length of a region with a certain range of hue or chroma in the hue image or chroma image are calculated, and the first hair and the second hair are detected based on that area and length.

[0131] (f) In the described embodiment, brown and blonde hair are detected based on a hue image, but it can also be configured to detect only one of brown and blonde hair based on a hue image. In this case, the first hair refers to hair that includes only one of brown and blonde hair.

[0132] Furthermore, in the described embodiment, black and white hair are detected based on a chroma image, but it can also be configured to detect only one of black and white hair based on a chroma image. In this case, the second hair refers to hair that includes only one of black and white hair.

[0133] Explanation of reference numerals in the attached figures 1: Printed substrate; 1a: Substrate to be inspected; 4: Resist area; 5: Solder paste; 13: Solder printing post-inspection device (substrate hair inspection device); 321: Illumination device (color image acquisition unit, main color image acquisition unit); 322: Camera (color image acquisition unit, main color image acquisition unit); 335: Hue image acquisition unit (hue image acquisition unit); 336: Chroma image acquisition unit (chroma image acquisition unit); 337: Resist area information acquisition unit (resist area information acquisition unit); 338: First hair detection unit (first hair detection unit); 339: Second hair detection unit (second hair detection unit).

Claims

1. A hair inspection apparatus for a substrate, for a printed circuit board having a green resist area and a solder paste printed thereon, for inspecting at least the resist area for hair, characterized in that, have: A color image acquisition unit uses multiple colored lights to acquire a color image related to a substrate under inspection, wherein the substrate under inspection is the printed substrate that is the object of inspection. A hue image acquisition unit uses the color image to obtain a hue image of the substrate under inspection; A chroma image acquisition unit uses the color image to obtain a chroma image of the substrate under inspection; The first hair detection unit is capable of detecting hairs containing at least brown and / or blonde hair as first hairs in at least the resist region of the hue image by utilizing the hue difference relative to the resist region. as well as The second hair detection unit is capable of detecting hairs containing at least black and / or white hair as second hairs in at least the resist region of the chroma image using the chroma difference relative to the resist region. The first hair detection unit is configured to detect the first hair based solely on the hue image without using the brightness image of the substrate being inspected. The second hair detection unit is configured to detect the second hair based solely on the chroma image without using the brightness image of the substrate being inspected.

2. The hair inspection device for a substrate according to claim 1, characterized in that, The hair inspection device includes a resist area information acquisition unit, which acquires resist area information for determining the extent of the resist area in the substrate being inspected. The first hair detection unit and the second hair detection unit are configured to detect the first hair and the second hair, at least the resist area determined by the resist area information obtained by the resist area information acquisition unit.

3. The hair inspection device for a substrate according to claim 2, characterized in that, The resist area information acquisition unit is configured to acquire the resist area information based on the design information and / or manufacturing information of the printed substrate.

4. The hair inspection device for a substrate according to claim 2, characterized in that, The hair inspection device includes a main color image acquisition unit, which uses multiple colored lights to acquire a main color image related to a main substrate, wherein the main substrate is a reference printed circuit board. The resist area information acquisition unit is configured to acquire the resist area information by obtaining a hue image of the main substrate using the main color image and extracting a region from the hue image that matches the hue of the resist area, and / or obtaining a chroma image of the main substrate using the main color image and extracting a region from the chroma image that matches the chroma of the resist area.

5. The hair inspection device for a substrate according to claim 2, characterized in that, The resist area information acquisition unit is configured to acquire the resist area information by extracting a region with the same hue as the resist area from the hue image of the substrate under inspection, and / or extracting a region with the same chroma as the resist area from the chroma image of the substrate under inspection.

6. A method for inspecting hair on a substrate, for a printed circuit board having a green resist area and a solder paste printed thereon, wherein at least the resist area is inspected for the presence or absence of hair, characterized in that, include: The color image acquisition process uses multiple colored lights to acquire a color image related to the substrate being inspected, which is the printed substrate that is the object of inspection. The hue image acquisition process uses the color image to obtain the hue image of the substrate under inspection; The chroma image acquisition process uses the color image to obtain a chroma image of the substrate under inspection; In the first hair detection step, in at least the resist area of ​​the hue image, hairs containing at least brown and / or blonde hair can be detected as first hairs by utilizing the hue difference relative to the resist area. as well as In the second hair detection step, in at least the resist region of the chroma image, hairs containing at least black and / or white hair can be detected as second hairs using the chroma difference relative to the resist region. In the first hair detection process, the detection of the first hair is performed based solely on the hue image, without using the brightness image of the substrate being inspected. In the second hair detection process, the detection of the second hair is performed based solely on the chroma image, without using the brightness image of the substrate being inspected.

7. The method for inspecting hair on a substrate according to claim 6, characterized in that, The method for inspecting hair on a substrate includes a resist area information acquisition step, in which resist area information is acquired to determine the range occupied by the resist area in the substrate being inspected. In the first hair detection step and the second hair detection step, at least the resist area determined by the resist area information obtained in the resist area information acquisition step is used as the inspection object for the detection processing of the first hair and the second hair.

Images