JP2008139260A - Image display unit and method, appearance inspection device, cream solder printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve inspection efficiency by stabilizing the standard of quality judgment by visual inspection. <P>SOLUTION: The appearance inspection device 1 includes: a camera 52 for picking up an image of a printed board P; a memory unit 61 for storing standard image data used as a standard to judge the quality of the state of the printed board P; a control unit 60 for producing a difference image based on the difference which is obtained by comparing an image of the printed board P picked up by the camera 52 with the standard image data stored at the memory unit 61; and a liquid crystal monitor 4 for displaying the difference image. In one example of the displayed picture shown in Fig. 8, the following images are simultaneously displayed at the respective display areas; at the upper left is a leftward displacement limit image, at the upper right are a difference image (a difference area D2) and a picked-up image of the printed board P, at the lower left is a standard image, and at the lower right are a difference image (a difference area D1) and the picked-up image of the printed board P. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image display device that displays an image for visual determination of a printed state of cream solder printed on a substrate, a mounted state of components mounted on the substrate, an appearance inspection device, a cream solder printer, And an image display method.

Conventionally, as one of methods for inspecting the appearance of a substrate, image data of a captured image of a substrate imaged by an imaging unit and reference image data (master data) serving as a reference for determining the quality of a substrate state And the degree of coincidence is examined (so-called pattern matching method). However, in this pattern matching method, it is difficult to predict all defect modes before inspection and prepare all reference images corresponding to these defects in advance. It may be erroneously determined as a defective product. As a countermeasure against such erroneous determination, in the appearance inspection apparatus described in Patent Document 1 below, the automatic determination means first determines the quality of the state of the object to be inspected arranged on the substrate, and the operator uses the automatic determination means. By visually determining an object to be inspected determined to be defective, a final determination on the object to be inspected is made. The display means has a function of simultaneously displaying the reference image created by the image processing means based on the reference image data stored in advance in the storage means together with the captured image of the object to be inspected.
JP-A-8-64999

  However, in this appearance inspection apparatus, it is necessary for the operator to compare the captured image of the object to be inspected with the reference image by his own observation and attention, and to judge pass / fail while imagining the difference between both images in his / her head. Therefore, for example, there is a possibility that the criteria for pass / fail judgment may differ depending on the operator, and it takes a lot of time to make the visual judgment, so that the efficiency of the inspection is greatly reduced.

  The present invention has been completed on the basis of the above-described circumstances, and it is an object of the present invention to stabilize the quality determination criteria and increase the inspection efficiency.

  An image display apparatus according to the present invention includes an imaging unit that images a substrate, a storage unit that stores reference image data serving as a reference for determining whether the state of the substrate is good, and a captured image of the substrate captured by the imaging unit. An image processing unit that compares the image data with the reference image data stored in the storage unit to obtain a difference, and creates a difference image based on the difference, and a display that simultaneously displays the difference image and a reference image that can be referred to in the determination. And a means.

  According to such a configuration, the image processing unit creates a difference image based on the difference between the image data of the captured image of the substrate obtained in the imaging step and the reference image data stored in the storage unit, and the display unit performs the difference. By displaying the image and the reference image at the same time, the difference between the captured image of the substrate and the reference image can be highlighted and determined with reference to the reference image. Therefore, it is possible to stabilize the criteria for the quality determination by the operator and increase the efficiency of the inspection.

The following configuration is preferable as an embodiment of the present invention.
The image processing unit may create a standard image based on the standard image data, and the display unit may have a function of displaying the standard image as a reference image. According to such a configuration, it is possible to compare the difference image with the reference image, and it is easier to make a quality determination than to make a determination using only the difference image.

  The display means may have a function of displaying a captured image of the substrate as a reference image. According to such a configuration, not only the difference image but also the captured image of the substrate can be referred to, so that it is easier to make an appropriate quality determination than the determination based on the difference image alone.

  The storage means can store standard image data indicating the normal state of the substrate, the image processing means creates a standard image based on the standard image data, and the display means has a function of displaying the standard image as a reference image. It is good also as a structure. According to such a configuration, it is possible to compare the difference image and the standard image, and it is easier to make a quality determination than to make a determination using only the difference image.

  The storage unit may store a plurality of types of reference image data, and the image processing unit may have a function of creating a difference image based on one reference image data selected from the plurality of types of reference image data. . According to such a configuration, it is possible to select reference image data suitable for quality determination. In addition, a plurality of reference images can be simultaneously displayed on the display unit together with the difference image thus created.

  The storage means can store standard image data indicating the normal state of the substrate, the image processing means creates a difference image using the standard image data as reference image data, and the display means has a function of displaying the difference image. It is good also as a structure. According to such a configuration, the difference between the captured image of the substrate and the standard image can be highlighted.

  Automatic determination means for comparing the image data of the captured image of the substrate with the reference image data and examining the degree of coincidence to determine the quality of the state of the object to be inspected, and the image display device; And the image processing means may constitute an appearance inspection apparatus having a function of creating a difference image for an object to be inspected determined to be defective by the automatic determination means. According to such an appearance inspection apparatus, it is not necessary to visually determine all the objects to be inspected, and only the objects to be inspected determined to be defective by the automatic determination means can be visually determined. Therefore, the efficiency of the inspection can be greatly increased as compared with the case where the total number is visually determined.

  Printing means for printing cream solder at a predetermined position on the substrate, and the image display device for displaying an image to assist in visually determining the printing state of the cream solder printed on the substrate by the printing means. A cream solder printing machine may be configured, or a printing means for printing cream solder at a predetermined position on the substrate, and the appearance inspection for inspecting the printing state of the cream solder printed on the substrate by the printing means. You may comprise the cream solder printing machine provided with the apparatus. According to such a cream solder printing machine, after the cream solder is printed on the substrate, it is possible to make a pass / fail judgment by inspecting the printing state of the cream solder.

  According to the present invention, determination criteria can be stabilized and visual determination can be performed efficiently.

<Embodiment 1>
1 and 2 schematically show a substrate visual inspection apparatus 1 according to an embodiment of the present invention. As shown in these drawings, the appearance inspection apparatus 1 has a box-like shape as a whole, a rear portion 2A constituting the rear side thereof, and a front portion 2B extending forward from a lower front end of the rear portion 2A. It has an A-shaped external shape in side view. The external appearance of such an appearance inspection apparatus 1 is formed by a casing Ca that covers internal components such as an inspection unit 50 described later.

  In the appearance inspection apparatus 1, the front portion 2B is provided with a loading / unloading port 6 for loading / unloading the printed circuit board P into / from the apparatus. The entrance / exit 6 includes an opening formed in the casing Ca, and is provided at the center in the width direction of the appearance inspection apparatus 1 (the center in the left-right direction in FIG. 2).

  A liquid crystal monitor 4 (corresponding to “display means” of the present invention) is disposed above the loading / unloading port 6 and on the front surface portion of the rear portion 2A. The liquid crystal monitor 4 is a so-called touch panel type liquid crystal display. Various information such as inspection results are displayed on the liquid crystal monitor 4, and the operator touches the monitor display with a fingertip to the appearance inspection apparatus 1. Various operation inputs can be performed.

  A maintenance door 9 is provided in a portion of the front side portion 2B aligned with the liquid crystal monitor 4. The door 9 is configured such that a part of the casing Ca can be opened and closed. When the door 9 is opened as necessary, an operator accesses the inside of the appearance inspection apparatus 1 to check the check pen 56 described later. It can be exchanged. Further, the upper surface cover Ca1 of the casing Ca is removable, and maintenance of the imaging unit 51 described later can be performed with the upper surface cover Ca1 removed.

  As shown in FIG. 1, the casing Ca is provided with handle portions 3 made of concave portions on both left and right sides of the rear portion 2 </ b> A, and the appearance inspection device 1 with the handle portion 3 held on the hand. Can be carried around. In FIGS. 1 and 2, reference numeral 8 denotes an emergency stop button.

  3 and 4 are diagrams for illustrating a specific internal configuration of the appearance inspection apparatus 1. As shown in the figure, a base frame 10 is provided inside the appearance inspection apparatus 1, and the base frame 10 holds a printed circuit board P and moves a substrate holding mechanism 24, and the substrate. An inspection unit 50 or the like for imaging the substrate P held by the holding mechanism 24 is assembled.

  The base frame 10 includes a base portion 12 having a front-falling inclined surface 12a whose height decreases toward the front side (side where the liquid crystal monitor 4 is installed), and both left and right ends of the base portion 12 And a side wall portion 14 that stands up from each other, and is formed of a cast product such as an aluminum die cast.

  The substrate holding mechanism 24 is fixed on the inclined surface 12a of the base portion 12, and is a linear motor type that moves the slider 22 in the front-rear direction (hereinafter referred to as the Y-axis direction) along the inclined surface 12a. It is composed of a single-axis robot 20 and a table 30 fixed to the slider 22.

  The table 30 holds the printed circuit board P, and in response to the operation of the single-axis robot 20, a home position (position indicated by a solid line in FIG. 3) that faces the loading / unloading port 6 and an imaging unit 51 described later. Is movable in the Y-axis direction over the inspection position (position indicated by a two-dot chain line in FIG. 3). The printed circuit board P is attached to and detached from the table 30 at the home position, and the image capturing unit 51 captures an image of the printed circuit board P with the table 30 moved from there to the inspection position.

  The table 30 includes a plate 32 fixed to the upper surface of the slider 22 and a pair of front and rear substrate holding frames 36 and 38 (hereinafter referred to as a front frame 36 and a rear frame 38) that are assembled to the plate 32 and extend in the left-right direction. The printed circuit board P is sandwiched between the frames 36 and 38. Specifically, the rear frame 38 of both the frames 36 and 38 is provided with a movable portion 39 that can be displaced in the Y-axis direction and is urged forward by an elastic member such as a compression coil spring. A stepped substrate receiving portion is formed in the portion where the portion 39 and the front frame 36 face each other. Then, when the front and rear edges of the printed board P are placed on these board receiving parts and the board P is fitted between the front frame 36 and the movable part 39 (see FIG. 3), the board P is caused by the elastic force of a compression coil spring or the like. Is elastically sandwiched between the frames 36 and 38, and accordingly, the printed circuit board P is held by the table 30 in a state of being positioned in the Y-axis direction with respect to the front frame 36. Further, a positioning plate 36a is provided on one end side in the left-right direction of the front frame 36, and one end (one end in the left-right direction) of the printed board P abuts on this plate 36a, so that the board P is moved in the left-right direction. (Hereinafter, referred to as the X-axis direction).

  The distance between the front and rear frames 36 and 38 is variable according to the substrate size.

  The inspection unit 50 includes a single-axis robot 40 that moves the slider 42 in the X-axis direction, and an imaging unit 51 that is assembled to the single-axis robot 40 via the slider 42.

  The single-axis robot 40 is a linear motor type single-axis robot similar to the single-axis robot 20 for driving the table 30 and is fixed to the base frame 10 in a state of being laid across the side wall portions 14. Has been.

  The imaging unit 51 includes a camera 52 (corresponding to the “imaging unit” of the present invention) that is an area sensor such as a CCD or a CMOS image sensor, and an illumination device 54 that irradiates illumination light to a printed circuit board P that is a subject. The camera 52 is configured to take an image of the printed circuit board P held on the table 30 from a direction orthogonal to the surface thereof. As the slider 42 moves in the X-axis direction, the imaging unit 51 can be moved to an imaging position above the single-axis robot 20 of the substrate holding mechanism 24 or to a position indicated by a two-dot chain line and a solid line in FIG. Yes. The image pickup unit 51 is held at the image pickup position in a normal state, and is moved to a position indicated by a two-dot chain line in FIG. 4 when the marking unit 55 is replaced as described later, or the upper surface cover Ca1 is moved. For example, when the removed imaging unit 51 is maintained, the imaging unit 51 is moved to a position indicated by a solid line in FIG.

  The inspection unit 50 is provided with a marking unit 55 for writing a predetermined mark on the printed circuit board P according to the inspection result or the like. The marking unit 55 is composed of a check pen 56 for entering a mark and a drive mechanism for driving the check pen 56 forward and backward. The check pen 56 is moved according to the operation of the drive mechanism. Advancing and retreating between a working position (a position indicated by a two-dot chain line in FIG. 3) abutting on the printed circuit board P held by 30 and a retreating position (a position indicated by a solid line in FIG. 3) retreating upward from this position. It is supposed to be.

  Further, as shown in FIG. 3, a driver that controls the driving of the single-axis robot 40 in the inspection unit 50 is provided above the installation portion of the substrate holding mechanism 24 and in a space behind the inspection unit 50. 66 is arranged. On the other hand, inside the base portion 12 of the base frame 10, a control unit (corresponding to “image processing means” and “automatic determination means” of the present invention) 60 for comprehensively controlling the appearance inspection apparatus 1 and the like. A driver 62 for the single-axis robot 20 of the substrate holding mechanism 24 is disposed.

The control unit 60 includes a CPU that executes logical operations, a ROM that stores various programs for controlling the CPU, a RAM that temporarily stores various data during operation of the apparatus, and an HDD that stores various data and software. Etc. As shown in the block diagram of FIG. 5, the control unit 60 includes single-axis robots 20 and 40 for the substrate holding mechanism 24 and the inspection unit 50, an imaging unit 51 (camera 52 and illumination device 54), markings. The unit 55, the liquid crystal monitor 4, and other various sensors not shown in the figure are electrically connected. Of these, the single-axis robots 20 and 40 are connected to the control unit 60 via the drivers 62 and 66, respectively. The control unit 60 comprehensively controls the operations of the single-axis robots 20 and 40, the imaging unit 51, and the like so as to proceed with a series of inspection operations on the printed circuit board P according to an operation program stored in advance. Based on the image picked up by 52, the quality of the printed circuit board P is determined, and the display content of the liquid crystal monitor 4 is controlled according to the determination result.

  In the appearance inspection apparatus 1 configured as described above, after the appearance inspection of the printed circuit board P is performed by the control unit 60, the captured image of the portion determined to be defective by the control unit 60 is displayed on the liquid crystal monitor 4. Visual judgment is performed by the operator. In the defective portion displayed on the liquid crystal monitor 4, a difference image between the defective image and the reference image is displayed. The reference image data, which is the image data of the reference image in the present embodiment, is composed of six types of limit image data, and a reference image based on the reference image data is created by the control unit 60. Specifically, the six types of limit images based on the six types of limit image data are the right shift limit image, the left shift limit image, the upper shift limit image, the lower shift limit image, and the large area limit image. And a small-area image.

  The deviation limit image is an image representing a non-defective state immediately before it is determined to be defective because the object to be inspected is displaced from the regular position on the printed circuit board P. The image refers to a deviation limit image in a case where the object to be inspected is arranged on the right side with respect to a normal position on the printed circuit board P. Further, the area large limit image is an image representing a non-defective product state immediately before being determined to be defective because the area of the object to be inspected is larger than a predetermined area on the printed circuit board P, and the area small limit image is It is an image showing a non-defective product state immediately before being determined to be defective because the area of the inspection object is smaller than a predetermined area on the printed circuit board P.

  Here, a method of creating a difference image in visual determination will be described. When the inspection surface of the printed circuit board P is imaged by the camera 52, the control unit 60 first uses the image data of the captured image of the printed circuit board P as a reference for determining the quality of the printed circuit board P. Processing for comparison with image data is performed. Specifically, the control unit 60 stores the reference image data in a storage unit (corresponding to “storage means” of the present invention) 61 (FIG. 5) provided therein, and this reference image. The data is compared with the image data of the captured image of the printed board P imaged by the camera 52, and a difference is taken. A difference image based on the difference is created. The difference image is created by, for example, aligning fiducial marks provided at a plurality of positions on the mounting surface of the printed circuit board P, the image data of the captured image of the printed circuit board P, the reference image data, and the like. Between the two images so that both images are aligned.

<Display mode on the liquid crystal monitor 4>
Next, a specific display method for simultaneously displaying the difference image displayed on the liquid crystal monitor 4 and a reference image that can be referred to in visual determination will be described. 6 to 9 show the display screen of the liquid crystal monitor 4 and show four typical display patterns. The difference areas D1 and D2 of the difference image are colored and displayed in a different color from the other areas, and the difference areas D1 and D2 and the areas other than the difference areas D1 and D2 can be clearly distinguished. The display screen of the liquid crystal monitor 4 is divided into four regions by dividing the display screen into two parts in the vertical and horizontal directions. In the following, a rectangular terminal portion (land) T formed on the printed circuit board P is divided. An example of a misalignment printed in a state where the cream solder (hereinafter simply referred to as solder) S is displaced will be described.

  The display pattern 1 (FIG. 6) is a standard image (a normal state of the printed circuit board P, that is, a state where the solder S is printed at an ideal printing position on the printed circuit board P as one of the reference images in the upper left area. The difference image and the captured image of the printed circuit board P are superimposed and displayed in the upper right area. The difference area D1 of the difference image based on the difference between the captured image of the printed circuit board P and the standard image is displayed in an area extending from the left side to the upper side in the display area of the solder S in the captured image of the printed circuit board P.

  The display pattern 2 (FIG. 7) is a left-side deviation limit image (a non-defective product when the solder S is shifted to the left side with respect to a predetermined printing position on the printed circuit board P as one of the reference images in the upper left area. The image showing the limit) is displayed, and the difference image and the captured image of the printed circuit board P are superimposed and displayed in the upper right area. The difference area D2 of the difference image based on the difference between the captured image of the printed board P and the left-side deviation limit image is displayed in an area extending from the left side to the upper side in the display area of the solder S in the captured image of the printed board P. Yes. The area of the left side part of the difference area D2 is smaller than the area of the left side part of the difference area D1 shown in FIG.

  Display pattern 3 (FIG. 8) displays a left-side deviation limit image as one of the reference images in the upper left area, and displays a difference image (difference area D2) and a captured image of printed circuit board P in the upper right area. The standard image is displayed in the lower left area, and the difference image (difference area D1) and the captured image of the printed circuit board P are displayed in the lower right area.

  Display pattern 4 (FIG. 9) displays a left-side deviation limit image as one of the reference images in the upper left area, and displays a difference image (difference area D2) and a captured image of printed circuit board P in the upper right area. A standard image is displayed as one of the reference images in the lower left area. Of the four display patterns described above, an operator can appropriately select one of the display patterns 1 to 4 that is suitable for visual determination according to the judgment of the operator. In the display patterns 1 to 4, the difference image (difference area D2) and the left-side deviation limit image are displayed in an overlapping manner, or the difference image (difference area D1) and the standard image are displayed in an overlapping manner as described above. It can also be displayed as one of the reference images.

<Creation procedure of limit image>
Next, a procedure for creating six types of limit images corresponding to misalignment defects (four types, top and bottom, left and right) and large / small area defects (two types, large and small) by the image processing means will be described with reference to FIG. . The misalignment defect is a defect in which the solder S is printed at a position deviated from a predetermined printing position on the printed circuit board P. Further, the large area / small defect is an abbreviation for large area defect and small area defect. The large area defect is a defect in which the area of the solder S printed on the printed circuit board P is larger than a predetermined area. The small area defect means a defect in which the area of the solder S printed on the printed circuit board P is printed smaller than a predetermined area.

  First, a substrate (hereinafter referred to as a solder-printed substrate P2) on which an object to be inspected (hereinafter referred to as a solder S1) is arranged at a normal position is imaged by an imaging means (hereinafter referred to as a camera 52). 11 As shown in the upper diagram, a captured image of the solder printed substrate P2 is acquired (S101). Image data of the solder S1 area image is extracted from the image data of the captured image of the solder printed board P2 (S102), and a solder S1 area image is created based on the image data of the solder S1 area image as shown in the lower diagram of FIG. To do. Next, a substrate 52 (hereinafter referred to as a raw substrate) P1 on which the solder S1 is not printed is picked up by the camera 52, and a picked-up image of the raw substrate P1 is acquired (S103).

  Then, the operator inputs a predetermined deviation allowable amount (hereinafter referred to as a position limit up / down / left / right specified value) with respect to the normal printing position by an input means such as a numeric keypad (S104), and stores the input position limit up / down / left / right specified value. The information is stored in the means (hereinafter referred to as the storage unit 61). Then, the image data of the solder S1 area image is moved in a predetermined direction (up, down, left and right directions) based on the position limit vertical and horizontal specified values stored in the storage unit 61, and the limit image data of the solder S1 area image is created ( S105). Then, by combining the limit image data of the solder region S1 image and the image data of the captured image of the raw substrate P1, limit image data (hereinafter referred to as positional deviation limit image data) L1 is created (S106). A misregistration limit image is created based on the misregistration limit image data L1. In this way, the right side deviation limit image shown in the upper part of FIG. 12, the left side deviation limit image shown in the lower part of FIG. 12, the upper side deviation limit image shown in the upper part of FIG. 13, and the lower side deviation limit image shown in the lower part of FIG. Is done.

  In addition, the operator inputs a predetermined variation ratio (hereinafter referred to as an area limit upper / lower specified value) with respect to the normal printing area by an input means such as a numeric keypad (S107), and the input area limit upper / lower specified value is stored in the storage unit 61. Remember. Then, the limit image data of the solder S1 area image is created by enlarging or reducing the image data of the solder S1 area image based on the area limit upper and lower defined values stored in the storage unit 61 (S108). Then, by combining the limit image data of the solder S1 region image and the image data of the captured image of the raw board P1, large / small limit image data L2 is created (S109). An area large / small limit image is created based on L2. In this way, the large area limit image shown in FIG. 16 and the small area limit image shown in the lower diagram of FIG. 16 are created.

  As the image creation software for creating the various limit images described above, an imaging process for imaging a substrate on which an object to be inspected is arranged and a substrate on which an object to be inspected is not arranged by an imaging means, and an input means A storage step for storing the input predetermined value, image data of a captured image of a substrate on which the inspection target obtained in the imaging step is arranged, and an inspection target obtained in the imaging step are arranged An extraction step of extracting the image data of the inspection target object by comparing the image data of the captured image of the non-substrate and taking the difference, and the image data of the inspection target object obtained in this extraction step A variation step of creating variation image data of the inspection object by varying based on the predetermined value stored in the storage step, the variation image data of the inspection object obtained in the variation step, and the A synthesis process for creating limit image data by synthesizing image data of a captured image of a substrate on which an inspection object is not arranged, and a limit image is generated by an image processing unit based on the limit image data obtained in the synthesis process. A configuration including an image creation process to be created is possible.

<Image display operation during inspection>
Next, the control operation of the control unit 60 in the appearance inspection apparatus 1 configured as described above will be described based on the flowchart shown in FIG. When the printed circuit board P is set to the table 30 at the home position (see the solid line in FIG. 3) through the slot 6 and the liquid crystal monitor 4 is touched to select “start inspection” from the menu screen (S201). Then, the single-axis robot 20 is operated to move the table 30 in the Y-axis direction, and in response to this, the printed circuit board P is moved to the inspection position indicated by the two-dot chain line in FIG. 3 (S202). Thereafter, the single-axis robot 40 is operated to position the imaging unit 51 above the printed board P in the inspection position, and the illumination device 54 is irradiated with illumination light to illuminate the printed board P, and the camera is in that state. The control signal is output to 52 to cause the printed circuit board P to be imaged, and a captured image of the printed circuit board P is acquired (S203).

  Then, the control unit 60 reads the limit image data from the storage unit 61 and compares the reference image data with the captured image of the printed circuit board P to calculate a difference element area s. And it is determined whether this area s is below the upper limit difference area A memorize | stored in the memory | storage part 61. FIG. If the area s is less than or equal to the upper limit area A, it is determined that no defect has occurred (S204), and the table 30 is moved from the inspection position to the home position. Thereafter, “end of inspection” and “start of inspection” are displayed on the liquid crystal monitor 4. When “Exit” is selected (S205), the inspection is terminated (S206). When “start inspection” is selected (S205), the process proceeds to S202 and the next inspection is performed.

  On the other hand, when the area s is larger than the upper limit area A, it is determined that a defect has occurred (S204), and it is determined whether the generated defect is a large / small area defect. If the area is large / small defective (S207), the large / small defect limit image data is read from the storage unit 61 (S208), and the large / small limit image data and the image data of the captured image of the printed circuit board P are read out. Are compared and a difference image based on the difference is created (S209). This difference image is displayed on the liquid crystal monitor 4 and a visual judgment is performed by the operator. At the same time, “determination NG” and “determination OK” are displayed on the liquid crystal monitor 4. As a result of the visual determination, if it is confirmed that it is defective and “determination NG” is selected (S210), the position data of the portion where the defect has occurred is stored in the storage unit 61 (S211), and the table 30 is inspected. The position is moved from the home position to the home position, and the process proceeds to S205 to determine whether or not the inspection is completed.

  Further, as a result of the visual determination by the operator, it is confirmed that it is not defective, and when “determination OK” is selected (S210), the table 30 is moved from the inspection position to the home position, the process proceeds to S205, and the inspection is completed. Judge whether or not.

  On the other hand, if it is determined that the generated defect is not a large / small area defect (S207), it is determined whether the defect is a misalignment defect. If it is determined that there is a misalignment (S212), the misalignment limit image data is read from the storage unit 61 (S213), and the misalignment limit image data is compared with the image data of the captured image of the printed circuit board P. And a difference image based on the difference is created (S214). This difference image is displayed on the liquid crystal monitor 4 and a visual judgment is performed by the operator. At the same time, “determination NG” and “determination OK” are displayed on the liquid crystal monitor 4. As a result of the visual determination, if it is confirmed that it is defective and “determination NG” is selected (S215), the position data of the portion where the defect has occurred is stored in the storage unit 61 (S216), and the table 30 is inspected. The position is moved from the home position to the home position, and the process proceeds to S205 to determine whether or not the inspection is completed.

  Further, as a result of the visual determination by the operator, it is confirmed that there is no defect, and when “determination OK” is selected (S215), the table 30 is moved from the inspection position to the home position, the process proceeds to S205, and the inspection is completed. Judge whether or not.

As described above, this embodiment can provide the following effects.
1. The difference image between the captured image of the printed circuit board P captured by the camera 52 and the limit image is displayed on the liquid crystal monitor 4, and the limit image is simultaneously displayed as one of the reference images at this time. The difference between the captured image and the limit image can be highlighted. Therefore, it is possible to stabilize the criteria for pass / fail judgment and improve the efficiency of the inspection by the operator's visual judgment.

  2. The difference image data and the imaged image data of the printed circuit board P are combined in a positioned state, and these are displayed in an overlapping manner, whereby it is possible to make a pass / fail judgment in consideration of circumstances peculiar to the printed circuit board P. For example, when a plurality of terminal portions T are arranged close to each other on the printed circuit board P, and a positional shift occurs in the arrangement direction of the terminal portions T, the distance to the adjacent terminal portions T is short, so that it is determined as defective. Even when the positional deviation occurs in the direction intersecting with the arrangement direction of the terminal portions T, it may not be determined to be defective even if the area of the difference image is the same.

3. A standard image as one of the reference images can be compared with an image obtained by combining a difference image based on the standard image and a captured image of the printed circuit board P (display pattern 1).
4). It is possible to compare the limit image as one of the reference images with an image obtained by combining the difference image based on the limit image and the captured image of the printed circuit board P (display pattern 2).
5. A limit image as one of the reference images, an image obtained by combining the difference image based on the limit image and the captured image of the printed circuit board P, a standard image as one of the reference images, and a difference image and the printed circuit board based on the standard image Comparison with an image obtained by combining P captured images is possible (display pattern 3).
6). A limit image as one of the reference images, an image obtained by combining a difference image based on the limit image and a captured image of the printed circuit board P, and a standard image as a reference image can be compared (display pattern 4).

7). A limit image suitable for creating a difference image can be appropriately selected from six types of limit images corresponding to the contents of the defect.
8). By visually determining only the portion determined to be defective in the automatic determination step, the time required for the inspection can be reduced as compared with the total number visual determination.
9. Since the display area of the difference image is displayed in a color different from the display area other than the difference image, the difference image is easy to see.

<Embodiment 2>
<Overall configuration>
FIG. 16 is a plan view of the cream solder printer 100 according to one embodiment of the present invention. As shown in this figure, the cream solder printing machine 100 includes a printing unit 130 that prints a printing material such as cream solder on a predetermined position on a printed circuit board P, and a printing state of the cream solder printed by the printing unit 130. A board printing table that reciprocates between a printing area with the printing unit 130 and an inspection area with the inspection unit 120 in a state where the printed board P on which the solder paste is printed is placed. 110. In addition, on the upstream side and the downstream side connected to the printing unit 130, a pair of substrate transport conveyors 105 are provided for carrying the printed board P into the printing area and carrying it out of the printing area.

  The printing unit 130 is installed on the front side (the lower side in the drawing) on the base 101, and the inspection unit 120 is installed on the back side of the printing unit 130. A work table 102 is fixed to the base 101 on the front side of the printing unit 130. On the work table 102, a keyboard 103 as input means and an image display device 104 according to the present invention are provided. The operator inputs various specified values (for example, the upper limit area A with respect to the area s of the difference element) using the keyboard 103, and visually inspects the appearance while viewing the difference image and the reference image simultaneously displayed on the image display device 104. It can be carried out.

<Configuration of Printing Unit 130>
A mask 137 having a predetermined mask pattern opening is held by a mask support frame 138 above the substrate moving table 110 and the substrate transfer conveyor 105 in the printing area. The mask support frame 138 is fixed to the upper part of a frame (not shown) integrated with the base 101. Cream solder is supplied onto the mask 137 from a nozzle (not shown), and the supplied cream solder is scratched with a squeegee 136 and embedded in the opening of the mask 137, whereby the cream solder is printed at a predetermined position on the printed circuit board P. be able to.

  In this way, the configuration of the printing unit 130 that moves the squeegee 136 in the Y direction while being in sliding contact with the mask 137 includes a squeegee unit 135 that moves the squeegee 136 up and down, and a configuration that extends in the X direction, and supports the squeegee unit 135. And a pair of Y direction guide rails 132 that support the squeegee unit support member 131 so as to be movable in the Y direction.

  Both Y-direction guide rails 132 are fixed to the upper part of a frame (not shown) integrated with the base 101. A Y-direction ball screw shaft 133 fitted to a ball nut fixed to the squeegee unit support member 131 is fixed to the side of the Y-direction guide rail 132 on the left side of the figure so as to be rotatable. A servo motor 134 that rotationally drives the Y direction ball screw shaft 133 is provided at the end of the Y direction ball screw shaft 133. This servo motor 134 is an upper part of a frame (not shown) integrated with the base 101. It is fixed to. As a result, the squeegee unit support member 131 is moved in the Y direction by the rotational drive of the servo motor 134.

<Configuration of the substrate moving table 110>
The substrate moving table 110 is composed of an upper member and a lower member, and the upper member is movable with respect to the lower member in respective predetermined ranges in the X, Y, Z, and R directions. As a result, the printed circuit board P placed on the upper member of the substrate moving table 110 is driven to move in the Z direction of the upper member so that the abutting position contacts the lower surface of the mask 137 and the separated position separates from the lower surface of the mask 137. Are moved in the Z direction.
The upper member of the substrate moving table 110 is provided with a substrate transfer conveyor 110A that is movable when the printed board P is carried in and out. When the upper member of the substrate moving table 110 is connected in alignment with the substrate transfer conveyor 105 in the Y direction and the Z direction, the substrate transfer conveyor 110A becomes ready to deliver the printed circuit board P before printing. The printed circuit board P carried in from the board conveying conveyor 105 is carried into and held at a predetermined position on the upper member of the board moving table 110. When the substrate transfer conveyor 110A is ready for delivery after printing or inspection, the printed or inspected printed substrate P held at a predetermined position on the upper member of the substrate moving table 110 is downstream. It is carried out to the board | substrate conveyance conveyor 105 of the side.

  A pair of Y-direction rails 111 that support the lower member of the substrate moving table 110 so as to be movable in the Y direction are fixed on the base 101. Between the two Y-direction rails 111 on the base 101, a Y-direction ball screw shaft 112 fitted to a ball nut (not shown) fixed to the lower member of the substrate moving table 110 is fixed to be rotatable. Yes. A servo motor 113 that rotationally drives the Y-direction ball screw shaft 112 is provided at the end of the Y-direction ball screw shaft 112. Thus, the substrate moving table 110 can be moved to a desired position in the Y direction by the rotational drive of the servo motor 113.

<Configuration of inspection unit 120>
The inspection unit 120 is configured to extend in the X direction, and includes a support member 121 whose both ends are fixed to the base 101 and an imaging device 122 supported by the support member 121 so as to be movable in the X direction. An X-direction ball screw shaft 123 fitted to a ball nut (not shown) fixed to the imaging device 122 is fixed to the support member 121 so as to be rotatable. A servo motor 124 for rotating the X direction ball screw shaft 123 is provided at the end of the X direction ball screw shaft 123. The servo motor 124 is fixed to a frame (not shown) integrated with the base 101. Has been. Thereby, the imaging device 122 can be moved to a desired position in the X direction by the rotational drive of the servo motor 124.

<Operation of Cream Solder Printing Machine 100>
First, the printed circuit board P is transported from the upstream side to a predetermined position on the upper member of the substrate table 110 by the substrate transport conveyors 105 and 110A. When the printed board P is held on the board conveyor 110A, the fiducial mark on the printed board P is imaged by a first camera (not shown), while the position of the mask 137 is taken by a second camera (not shown). An alignment mark is imaged. When the upper member of the substrate table 110 moves in the X direction, the Y direction, or the R axis direction with respect to the lower member, the position correction is performed so that the fiducial mark and the alignment mark coincide with each other. Further, the upper member of the substrate table 110 rises in the Z direction from the separated position to the contact position with the position corrected, and the printed circuit board P contacts the lower surface of the mask 137. Then, the squeegee unit 135 is moved down in the Z direction by the squeegee unit 135 and comes into contact with the mask 137, and the squeegee unit support member 131 and the squeegee 136 are integrally moved in the Y direction by the rotational drive of the servo motor 134. Printing is performed on the printed circuit board P through the opening of the mask 137. When printing is completed, the squeegee 136 is raised, the upper member of the substrate table 110 is lowered from the contact position to the separation position, and is moved in the X direction, the Y direction, or further in the R axis direction, thereby correcting the position. Return to the previous state.

  Next, the substrate table 110 is moved to the inspection area by the rotational drive of the servo motor 113. The imaging device 122 first images a fiducial mark on the printed circuit board P, and the coordinate system on the printed circuit board P is recognized by the control device. In order to position the imaging device 122 at predetermined X and Y coordinates of the printed circuit board P, the servo motor 113 and the servo motor 124 are rotationally driven. As the imaging by the imaging device 122 proceeds, automatic determination is made as to whether the cream solder printed on the printed circuit board P is good or bad. After completion of the automatic determination without being judged as defective, the rotation of the servo motor 113 causes the substrate transport conveyor 110A of the substrate table 110 to move in the Y direction to a position that coincides with the substrate transport conveyor 105 in the printing area. Then, it is carried out downstream. If the defect determination is made during the automatic determination, the substrate display 110 starts to move in the Y direction after the determination of all the locations, and the image display device 104 is to be checked for visual inspection by the operator. The difference image and the reference image are displayed simultaneously. If it is determined to be defective even by visual inspection, the printed board P can be removed from the board table 110.

  As described above, since the cream solder printer 100 includes the image display device 104 in the present embodiment, the printing state is automatically determined immediately after printing by the printing unit 130, and if the defect is determined by automatic determination, the image display device 104 is determined. The difference image and the reference image can be displayed simultaneously. Therefore, the time required for visual inspection by the operator can be shortened, and as a result, the tact time in the cream solder printing process can be shortened.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.

  (1) In the present embodiment, the captured image of the printed circuit board P and the difference image are illustrated as being overlapped and displayed in the same display area of the liquid crystal monitor 4, but according to the present invention, the captured image of the printed circuit board P is captured. The image and the difference image may be displayed in different display areas.

  (2) In the present embodiment, the left shift limit image displayed on the liquid crystal monitor 4 as a reference image in FIGS. 6 to 9 is illustrated, but according to the present invention, the limit image displayed on the liquid crystal monitor 4 The number of types is not limited to one, and a plurality of limit images may be displayed side by side on the liquid crystal monitor 4. For example, in the third display pattern (FIG. 8), the standard image is displayed in the lower left display area, and the difference image (difference area D1) and the captured image of the printed circuit board P are displayed in the lower right display area. However, according to the present invention, the upper shift limit image may be displayed in the lower left display area, and the difference image based on the upper shift limit image and the captured image of the printed circuit board P may be displayed in the lower right display area. .

  (3) In this embodiment, an application example in which the solder S is printed on the terminal portion T on the printed circuit board P is described. However, according to the present invention, an electronic component is formed on the terminal portion T on which the solder S is printed. This can also be applied to the case where is mounted.

  (4) In the present embodiment, the difference area is colored and displayed in a color different from the color of the area other than the difference area. However, according to the present invention, the difference area may not be colored and displayed. For example, the difference area may be specified by surrounding the difference area with a broken line or by hatching the difference area with an oblique parallel line or the like.

  (5) In the present embodiment, the display area of the liquid crystal monitor 4 is illustrated as being divided into four parts. However, according to the present invention, the display area may be divided according to the number of images to be displayed. For example, in the first display pattern (FIG. 6), the display area of the liquid crystal monitor 4 may be divided into two to be displayed.

  (6) In the present embodiment, the misalignment defect in the vertical and horizontal directions and the large / small defect in the area are illustrated as the defect modes. However, according to the present invention, other defects may be used. (A defect in which a different type of solder is printed from a normal type of solder). When this solder error defect occurs, it may be detected that a different type of solder is printed depending on the color of the solder.

The perspective view which shows the external appearance inspection apparatus concerning one Embodiment of this invention. The top view which shows the said external appearance inspection apparatus Longitudinal sectional view showing the internal configuration of the appearance inspection apparatus A flat view showing the internal configuration of the appearance inspection apparatus. Block diagram showing a control system of the appearance inspection apparatus The figure which showed the display image of the 1st display pattern displayed on a liquid crystal monitor. The figure which showed the display image of the 2nd display pattern displayed on a liquid crystal monitor The figure which showed the display image of the 3rd display pattern displayed on a liquid crystal monitor. The figure which showed the display image of the 4th display pattern displayed on a liquid crystal monitor Flow chart showing the limit image creation procedure The figure which showed a mode that a solder printing area was extracted from a picked-up image The upper row shows the right-side deviation limit image, and the lower row shows the left-side deviation limit image. The upper figure shows the upper deviation limit image, and the lower figure shows the lower deviation limit image. The upper row shows a large area limit image, and the lower row shows a small area limit image. Flow chart showing contents of control operation by control unit The top view which shows the cream solder printer concerning one Embodiment of this invention

Explanation of symbols

1. Visual inspection device (image display device)
4. Liquid crystal monitor (display means)
52. Camera (imaging means)
60. Control unit (image processing means, automatic determination means)
61: Storage unit (storage means)
D1, D2 ... Difference area S ... Cream solder T ... Terminal part P ... Printed circuit board

Claims (10)

Imaging means for imaging the substrate;
Storage means for storing reference image data serving as a reference for determining the quality of the state of the substrate;
An image processing unit that compares the image data of the captured image of the substrate imaged by the imaging unit with the reference image data stored in the storage unit, creates a difference, and creates a difference image based on the difference;
An image display device comprising: display means for simultaneously displaying the difference image and a reference image that can be referred to in determination. The image display device according to claim 1, wherein the image processing unit creates a standard image based on the standard image data, and the display unit has a function of displaying the standard image as the reference image. The image display device according to claim 1, wherein the display unit has a function of displaying a captured image of the substrate as the reference image. The storage means can store standard image data indicating a normal state of the substrate, the image processing means creates a standard image based on the standard image data, and the display means uses the standard image as the reference image. The image display device according to any one of claims 1 to 3, which has a function of displaying an image. The storage means can store a plurality of types of reference image data, and the image processing means creates the difference image based on one reference image data selected from the plurality of types of reference image data. The image display device according to claim 1, further comprising: 2. The storage unit can store standard image data indicating a normal state of the substrate, and the image processing unit has a function of creating a difference image using the standard image data as the reference image data. Item 6. The image display device according to any one of Items 5. Automatic determination means for comparing the image data of the captured image of the substrate with the reference image data and examining the degree of coincidence to determine the quality of the object to be inspected arranged on the substrate; An image display device according to any one of claims 1 to 6, wherein the image processing means has a function of creating the difference image for an object to be inspected determined to be defective by the automatic determination means. Appearance inspection device. The printing means for printing cream solder at a predetermined position on the substrate, and an image for assisting visual judgment of the printing state of the cream solder printed on the substrate by the printing means are displayed. A cream solder printing machine comprising the image display device according to Item 6. The cream solder provided with the printing means which prints cream solder in the predetermined position on a board | substrate, and the external appearance inspection apparatus of Claim 7 which test | inspects the printing state of the cream solder printed on the said board | substrate by the said printing means Printer. An image display method for displaying an image to assist an operator to visually determine the quality of a substrate,
An imaging step of imaging the substrate by an imaging unit, reference image data stored in a storage unit in advance as a reference for determining the quality of the substrate, and an image of the captured image of the substrate obtained in the imaging step A difference image creating step for comparing the data and taking a difference, and creating a difference image based on the difference by the image processing means, and an image display step for causing the display means to simultaneously display the reference image that can be referred to in the determination as the difference image An image display method comprising:

Images