JP2009168453A - Inspection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain three-dimensional image having no hidden surface (occlusion) in three-dimensional automatic inspection of solder paste printing. <P>SOLUTION: Automatic three-dimensional image inspection of solder paste printing quality having no hidden surface (occlusion) is performed by constituting three-dimensional imaging geometrical-optical arrangement of a binocular vision system wherein the first color image sensor camera and the second color image sensor camera are faced each other over a substrate surface, for imaging the same domain on the substrate by looking down with an oblique optical axis (viewing angle); a third hue light source for illuminating the substrate from a right upper direction; a first hue light source placed on a lower position than the first camera, for illuminating the substrate from the same direction as the first camera; and a second hue light source placed on a lower position than the second camera, for illuminating the substrate from the same direction as the second camera. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an inspection apparatus for performing an appearance inspection by three-dimensionally imaging a cream solder printed board with an image sensor camera in an electronics factory or the like.

The recent method of assembling parts on a printed circuit board is almost surface-mounting, and cream solder is printed on the base board in a photocopied form, then the parts are automatically mounted, and the cream solder is heated and melted in a reflow oven. Complete soldering of components to the board. Component mounting defects in this method can occur in the cream solder printing process, the component mounting process, and the solder melting process, so that the necessity to inspect and confirm the quality in each process has been generally recognized.
In particular, printing defects in the cream solder printing process cause serious soldering defects, and therefore automatic inspection of solder printing quality by an inspection apparatus has become essential. This type of conventional inspection apparatus is roughly classified into a two-dimensional detection method and a three-dimensional measurement method. The former detects a defect in the plane direction of printing from a plane image taken from the direction perpendicular to the substrate. In the latter case, the height of the printed solder is measured by three-dimensional measurement.
In the three-dimensional measurement method, a laser beam is projected onto the solder from an oblique direction and calculated from the position change amount of the reflected spot depending on the height, or a structural light having a known pattern is projected and calculated from the deformation. A method is disclosed (see Patent Documents 1 and 2).
JP 2000-097631 A JP-A-2005-337943

  On the other hand, the present applicant has devised and applied for a cream solder three-dimensional inspection technique that includes two types of light sources having different angles and hues from a tilt camera (not disclosed). In this technique, a one-dimensional color image sensor having an oblique imaging angle with respect to a substrate illuminates the first hue light source from almost directly above and the second hue light source illuminates at an oblique angle shallower than the imaging angle. To obtain a three-dimensional image of the entire surface of the cream solder printed board that has been double-illuminated with the first hue light and the second hue light. It detects and performs three-dimensional image measurement of cream solder for an abnormal part.

  In this technology, since the substrate is imaged obliquely from one direction with one camera, the acquired image is only the top and front side images of the three-dimensional printed cream solder, and the opposite side surface is a hidden surface or occlusion, It could not be the subject of inspection and measurement. In an actual substrate, there is an abnormality on the occlusion side, and there is a case where an inspection on the opposite side is necessary.

  The problem to be solved is that in the cream solder 3D inspection apparatus, a 3D image of the printed cream solder without occlusion was acquired, and 3D inspection and 3D measurement could not be performed.

In the present invention, the first color image sensor camera and the second color image sensor camera face each other above the substrate surface, and the same region of the substrate is imaged by looking down at an oblique viewing axis (viewing angle). An imaging means comprising a system and a substrate stage, both cameras each acquiring a three-dimensional image of the substrate, a third hue light source that illuminates the substrate from directly above, and a lower position than the first camera, the first camera A first hue light source that illuminates the substrate from the same direction and a second hue light source that is positioned lower than the second camera and that illuminates the substrate from the same direction as the second camera. Illuminating means for illuminating the image, and image position correcting means for correcting the position of both images using the reference point image in each of the substrate images taken simultaneously by the first camera and the second camera Storage means for storing images captured by both cameras, first differential image processing of the reference substrate image and the sample substrate image captured by the first camera, and a first difference between the reference substrate image and the sample substrate image captured by the second camera Image processing means for performing two difference image processing, detection means for detecting a pixel having a difference exceeding a set threshold as a different pixel in each of the first difference image processing and the second difference image processing, and each detected The main feature is that it comprises integrated determination means for determining the quality of cream solder print quality in an integrated manner from the different pixels.
In the present invention, the first color image sensor camera and the second color image sensor camera oppose each other above the substrate surface, and the same region of the substrate is imaged by looking down at an oblique viewing axis (viewing angle). An imaging system comprising a visual system and a substrate stage, both cameras each acquiring a three-dimensional image of the substrate, a third hue light source that illuminates the substrate from directly above, and a first position that is lower than the first camera. A first hue light source that illuminates the substrate from the same direction as the camera, and a second hue light source that is positioned lower than the second camera and that illuminates the substrate from the same direction as the second camera. Image position correction for correcting the position of both images using a reference point image in the illumination means for illuminating in triplicate and the respective substrate images captured simultaneously by the first camera and the second camera A storage means for storing images captured by both cameras, a first differential image processing of a reference substrate image and a sample substrate image captured by the first camera, and a reference substrate image and a sample substrate image captured by the second camera Image processing means for performing each of the second difference image processing, and detection means for detecting pixels having a difference exceeding a set threshold as different pixels in each of the first difference image processing and the second difference image processing. The main feature is that it comprises integrated determination means for determining the quality of cream solder print quality in an integrated manner from each different pixel.

  The inspection apparatus of the present invention images cream solder obliquely from opposite directions with two image sensor cameras, and colors the upper, near side, and opposite sides of the cream solder in the respective hues with three color-specific color light sources. Since it illuminates, there is an advantage that inspection and measurement of cream solder without occlusion becomes much easier.

  The purpose of realizing a three-dimensional cream solder printing inspection device that can easily inspect and measure cream solder without occlusion is to image cream solder diagonally from two opposite directions with two image sensor cameras, and separate the three hues. This was realized by illuminating the upper, near and opposite sides of the cream solder with a color light source.

  FIG. 1 is an overall configuration diagram of a first embodiment of an inspection apparatus according to the present invention, in which cream solder 2 is printed on a substrate 1, and the substrate 1 is held in a horizontal posture on a one-dimensional table 3.

Above the substrate 1, there are two one-dimensional color image sensor cameras 4-1 and 4-2, a first hue light source 5-1, a second hue light source 5-2, and a third hue light source 5- of the illumination device. 3 is arranged.

  The one-dimensional color image sensor cameras 4-1 and 4-2 are color line CCD cameras, and are installed at two vertices on the bottom of an inverted isosceles triangle (indicated by a dotted line in FIG. 1) having one point on the substrate as a vertex. Thus, the same region of the substrate is imaged with an oblique visual axis.

  The first hue light source 5-1 illuminates the substrate from the same direction as the first camera at a position lower than the first camera 4-1, and the second hue light source 5-2 is lower than the second camera 4-2. The substrate is illuminated from the same direction as the second camera at the position, and the third hue light source 5-3 is illuminating the substrate from directly above.

As shown in the schematic diagram of the optical arrangement in FIG. 2A, the configuration of the illumination / imaging system is as follows:
The first hue light source 5-1 is installed below the one-dimensional color image sensor camera 4-1, and the first hue light, for example, a red luminous flux is projected onto the substrate to color the side surface of the cream solder in red. .
The second hue light source 5-2 is installed below the one-dimensional color image sensor camera 4-2, and colors the side surface of the cream solder to green by projecting the second hue light, for example, a green light beam, onto the substrate. .
The third hue light source 5-3 is installed immediately above the camera field of view, and projects the third hue light, for example, blue light flux, onto the substrate, thereby coloring the upper surface of the cream solder in blue.

When the one-dimensional color image sensor camera 4-1 in an oblique posture installed between the first hue light source 5-1 and the third hue light source 5-3 captures the substrate with this geometric optical arrangement, FIG. As shown in the image schematic diagram, a three-dimensional image of cream solder is obtained, and the upper surface of the solder is a blue image region, and the side surface is a red image region.
Since the depth of the red region (corresponding to the width of the rectangular region in FIG. 2B) is the depth of the side image of the cream solder, it is proportional to the height of the cream solder, and the blue region is the top image of the cream solder. It is proportional to the area of cream solder.

In addition, when the geometric optical arrangement is used to image the substrate by the oblique one-dimensional color image sensor camera 4-2 installed between the second hue light source 5-2 and the third hue light source 5-3, FIG. 3), a three-dimensional image of cream solder is obtained, and the upper surface of the solder is a blue image region, and the side surface is a green image region.
Since the depth of the green region (corresponding to the lateral width of the rectangular region in FIG. 2B) is the depth of the side image of the cream solder, it is proportional to the height of the cream solder, and the blue region is the top image of the cream solder. It is proportional to the area of cream solder.

  In the above image, since the one-dimensional image sensor camera acquires the entire field of view at a constant inclination angle, the relationship between the image depth (horizontal width of the rectangular area in FIG. 2B) and the actual substrate size is constant everywhere in the image. Therefore, the actual size can be easily calculated from the tilt angle of the camera by trigonometry. Moreover, since the image of the printed cream solder which is a three-dimensional object is taken from both directions with two cameras, image measurement without occlusion is possible.

  The two cameras need to capture the same field of view, and for this purpose, the same reference point is set on the substrate, and position correction is performed on images acquired by the respective cameras.

  The protrusion or bridge of cream solder is detected as an abnormality in the spread of the blue region in any camera image.

  1, the one-dimensional color image sensor cameras 4-1 and 4-2 are connected to the control device 6, and the control device 6 includes two one-dimensional sensor imaging units 7 and two image positions. A correction unit 8, a three-dimensional image extraction unit 9, a three-dimensional image measurement unit 10, a solder quality determination unit 11, and an integrated system control unit 12 that controls the entire system. Exchange.

  The control device 6 includes an input unit 13 for inputting teaching data, an output unit 14 for printing inspection results, a communication unit 15 for transmitting / receiving data to / from an external device, and images and inspection results. Are connected to each other.

  Next, the teaching steps of this embodiment inspection apparatus will be described with reference to the flowchart of FIG. First, the reference board 1 (FIG. 1) on which the cream solder is correctly printed is loaded on the table (ST1), the ID data of the board is taught (ST2), and the inspection area is taught (ST3). The inspection area is set around a place (called a pad) where the cream solder is printed. This teaching can utilize computer design data of the substrate. Thereafter, the reference substrate is moved on the one-dimensional table 3, and scanning imaging is simultaneously performed by the one-dimensional color image sensor cameras 4-1 and 4-2 (ST4). The acquired two images of the entire three-dimensional surface of the reference substrate are displayed on the corresponding display units 16, respectively, and specific portions in both images are set as position correction marks (ST5). The position correction mark is usually set at a diagonal corner of the substrate, but can be set anywhere on the substrate if necessary. Next, the inspection area taught in ST3 is superimposed on the image and the correspondence between the image and the inspection area is confirmed (ST6).

When the teaching step is completed, the reference substrate is removed (ST7).

Next, the automatic inspection operation in this embodiment will be described with reference to the flowchart of FIG.
First, in FIG. 1, the sample substrate 1 is loaded on the one-dimensional table 3 (ST11), and when the ID data of the sample substrate is input or read (ST12), the sample substrate 1 is moved one-dimensionally according to a command from the control device 6. The sample substrate 1 is simultaneously scanned and imaged by the one-dimensional color image sensor cameras 4-1 and 4-2 under the control of the one-dimensional sensor imaging unit 7 (ST13).

  Therefore, the three-dimensional image extraction unit 9 extracts red pixels and blue pixels exceeding the threshold value from the image in the inspection area in the first camera image. In the second camera image, green pixels and blue pixels exceeding the threshold are extracted from the image in the inspection area (ST14), and the three-dimensional image measurement unit 10 determines the area and height of the cream solder for all the inspection areas of both images. The volume is measured (ST15) (see FIG. 2B).

  Next, the solder quality determination unit 11 integrates the measurement data of all the inspection areas obtained from both images, determines the quality of the printed cream solder (ST16), and reports the inspection result (ST17). Then, the specimen substrate is removed (ST18).

  FIG. 4 is a diagram showing the overall configuration of the second embodiment of the inspection apparatus according to the present invention. The substrate 1, the printed cream solder 2, the one-dimensional table 3, and the two one-dimensional color image sensor cameras 4- 1 and 4-2, and the arrangement of the first hue light source 5-1, the second hue light source 5-2, and the third hue light source 5-3 of the lighting device are the same as in the first embodiment. Omitted.

  4, the one-dimensional color image sensor cameras 4-1 and 4-2 are connected to the control device 6, and the control device 6 has two one-dimensional sensor imaging units 7 and two image positions. A correction unit 8, a three-dimensional image comparison unit 9, a solder pass / fail judgment unit 10, and an integrated system control unit 11 that controls the entire system, and the units 7 to 11 exchange data through a bus 16.

  The control device 6 includes an input unit 12 for inputting teaching data, an output unit 13 for printing inspection results, a communication unit 14 for transmitting / receiving data to / from an external device, and images and inspection results. Are connected to each other.

  Next, the teaching steps of this embodiment inspection apparatus will be described with reference to the flowchart of FIG. First, the reference board 1 (FIG. 4) on which the cream solder is correctly printed is loaded on the table (ST21), the ID data of the board is taught (ST22), and the inspection area is further taught (ST23). The inspection area is set around a place (called a pad) where the cream solder is printed. This teaching can utilize computer design data of the substrate. Thereafter, the reference substrate is moved on the one-dimensional table 3 and simultaneously scanned and imaged by the one-dimensional color image sensor cameras 4-1 and 4-2 (ST24). The obtained two images of the entire three-dimensional surface of the reference board are displayed on the corresponding display units 15 respectively, and specific portions in both images are set as position correction marks (ST25). The position correction mark is usually set at a diagonal corner of the substrate, but can be set anywhere on the substrate if necessary. Next, the inspection area taught in ST23 is superimposed on the image, and the correspondence between the image and the inspection area is confirmed (ST26).

Next, a test substrate is loaded (ST28), moved by the one-dimensional table 3, and scanned and imaged simultaneously by the one-dimensional color image sensor cameras 4-1 and 4-2 (ST29). Display the three-dimensional image 2 of the reference board and the three-dimensional image 2 of the test board on the display unit 15 respectively, and try the difference image processing between the two under the conditions of the default image accuracy and the default detection sensitivity. If there is an oversight, the image accuracy or detection sensitivity of the inspection area is increased, and if there are many overdetections, those of the inspection area are decreased to adjust the image accuracy and detection sensitivity optimal for this substrate ( ST30).
When the adjustment of the image accuracy and detection sensitivity of all the inspection areas is completed and the teaching step is completed, the test substrate is removed (ST31).

As for the image accuracy, it is possible to select whether all pixels in the inspection area are compared or thinned out. When all the pixels are targeted, the inspection accuracy is naturally improved, but the image processing time becomes long. Therefore, a necessary pixel density is applied depending on the type of substrate and the type of defect so that the inspection time can be shortened.
The detection sensitivity of the inspection region is roughly classified into difference sensitivity that raises and lowers the threshold value of the difference image processing, and sensitivity that limits the range of pixel expansion and movement exceeding the threshold value. By detecting the range of different pixels, it is possible to detect not only the protrusion or deficiency of the cream solder printed on the substrate in the planar direction, but also the height defect.
When the difference image processing between the images of the substrates to be compared with the reference substrate is performed, for example, when the height of the cream solder on the sample substrate is higher than that of the sample substrate, as shown in the lower column of FIG. A difference image is obtained, and an imaging inspection about the height is possible.

Next, the automatic inspection operation in this embodiment will be described with reference to the flowchart of FIG.
First, in FIG. 4, the sample substrate 1 is loaded on the one-dimensional table 3 (ST41), and when the ID data of the sample substrate is input or read (ST42), the sample substrate 1 is moved one-dimensionally according to the command of the control device 6. Under the control of the one-dimensional sensor imaging unit 7, the entire surface of the specimen substrate 1 is simultaneously scanned and imaged by the one-dimensional color image sensor cameras 4-1 and 4-2 (ST43).

  Therefore, the three-dimensional image comparison unit 9 performs difference image processing on each inspection region of the reference substrate three-dimensional image and the sample substrate three-dimensional image (ST44), and detects different pixels based on the taught image accuracy and detection sensitivity. (ST45).

  Next, the solder pass / fail judgment unit 10 integrates the different pixel data obtained from both images, judges the quality of the printed cream solder (ST46), and reports the inspection result (ST47). Is removed (ST48).

  FIG. 6 is an overall configuration diagram of a third embodiment of the inspection apparatus according to the present invention, in which cream solder 2 is printed on a substrate 1 and the substrate 1 is held on an XY table 3 in a horizontal posture.

  Above the substrate 1 are two two-dimensional color image sensor cameras 4-1 and 4-2, and a first hue light source 5-1, a second hue light source 5-2, and a third hue light source 5- of the illumination device. 3 is arranged.

  The two-dimensional color image sensor cameras 4-1 and 4-2 are color area CCD cameras and are installed at the two vertices of the base of an inverted isosceles triangle (indicated by the dotted line in FIG. 1) having one point on the substrate as the apex. Thus, the same region of the substrate is imaged with an oblique visual axis.

  The first hue light source 5-1 illuminates the substrate from the same direction as the first camera at a position lower than the first camera 4-1, and the second hue light source 5-2 is lower than the second camera 4-2. The substrate is illuminated from the same direction as the second camera at the position, and the third hue light source 5-3 is illuminating the substrate from directly above.

As shown in the schematic diagram of the optical arrangement in FIG. 2A, the configuration of the illumination / imaging system is as follows:
The first hue light source 5-1 is installed below the two-dimensional color image sensor camera 4-1, and the first hue light, for example, a red luminous flux is projected onto the substrate to color the side surface of the cream solder in red. .
The second hue light source 5-2 is installed below the two-dimensional color image sensor camera 4-2, and colors the side surface of the cream solder to green by projecting the second hue light, for example, a green light beam, onto the substrate. .
The third hue light source 5-3 is installed immediately above the camera field of view, and projects the third hue light, for example, blue light flux, onto the substrate, thereby coloring the upper surface of the cream solder in blue.

When the two-dimensional color image sensor camera 4-1 in an oblique posture installed between the first hue light source 5-1 and the third hue light source 5-3 images the substrate with this geometric optical arrangement, FIG. As shown in the image schematic diagram, a three-dimensional image of cream solder is obtained, and the upper surface of the solder is a blue image region, and the side surface is a red image region.
Since the depth of the red region (corresponding to the width of the rectangular region in FIG. 2B) is the depth of the side image of the cream solder, it is proportional to the height of the cream solder, and the blue region is the top image of the cream solder. It is proportional to the area of cream solder.

Further, in this geometric optical arrangement, when the two-dimensional color image sensor camera 4-2 in an oblique posture installed between the second hue light source 5-2 and the third hue light source 5-3 images the substrate, FIG. 3), a three-dimensional image of cream solder is obtained, and the upper surface of the solder is a blue image region, and the side surface is a green image region.
Since the depth of the green region (corresponding to the lateral width of the rectangular region in FIG. 2B) is the depth of the side image of the cream solder, it is proportional to the height of the cream solder, and the blue region is the top image of the cream solder. It is proportional to the area of cream solder.

  Since the two-dimensional image sensor camera acquires an image at a constant tilt angle, the height and area of the solid can be calculated by trigonometry. Moreover, since the image of the printed cream solder which is a three-dimensional object is taken from both directions with two cameras, image measurement without occlusion is possible.

  The two cameras need to capture the same field of view, and for this purpose, the same reference point is set on the substrate, and position correction is performed on images acquired by the respective cameras.

  The protrusion or bridge of cream solder is detected as an abnormality in the spread of the blue region in any camera image.

  6, the two-dimensional color image sensor cameras 4-1 and 4-2 are connected to the control device 6, and the control device 6 includes two two-dimensional sensor imaging units 7 and two image positions. A correction unit 8, a three-dimensional image extraction unit 9, a three-dimensional image measurement unit 10, a solder quality determination unit 11, and an integrated system control unit 12 that controls the entire system. Exchange.

  The control device 6 includes an input unit 13 for inputting teaching data, an output unit 14 for printing inspection results, a communication unit 15 for transmitting / receiving data to / from an external device, and images and inspection results. Are connected to each other.

  Next, the teaching steps of this embodiment inspection apparatus will be described with reference to the flowchart of FIG. First, the reference board 1 (FIG. 6) on which the cream solder is correctly printed is loaded on the XY table (ST51), the board ID data is taught (ST52), and the inspection area is taught (ST53). The inspection area is set around a place (called a pad) where the cream solder is printed. This teaching can utilize computer design data of the substrate. Thereafter, the reference substrate is moved by the XY table 3, and the same visual field is simultaneously imaged by the two-dimensional color image sensor cameras 4-1 and 4-2 (ST54). The acquired two images of the reference board are displayed on the corresponding display units 16, respectively, and specific positions in both images are set as position correction marks (ST55). The position correction mark is normally set at a diagonal corner of the substrate, but can also be set in each field of view of the substrate if necessary. Next, the inspection area taught in ST53 is displayed superimposed on the field-of-view image, and the correspondence between the image and the inspection area is confirmed (ST56).

When the teaching step is completed, the reference substrate is removed (ST57).

Next, the automatic inspection operation in this embodiment will be described with reference to the flowchart of FIG.
First, in FIG. 6, the specimen substrate 1 is loaded on the XY table 3 (ST61), and when the ID data of the specimen substrate is input or read (ST62), the specimen substrate 1 is two-dimensionally moved by the command of the control device 6, Under the control of the two-dimensional sensor imaging unit 7, the two-dimensional color image sensor cameras 4-1 and 4-2 simultaneously image each field of view of the sample substrate 1 (ST63).

  Therefore, the three-dimensional image extraction unit 9 extracts red pixels and blue pixels exceeding the threshold value from the image in the inspection area in the field-of-view image of the first camera. Further, in the field-of-view image of the second camera, green pixels and blue pixels exceeding the threshold are extracted from the image in the inspection area (ST64), and the three-dimensional image measurement unit 10 The height and volume are measured (ST65) (see FIG. 2B).

  Next, the solder quality determination unit 11 integrates the measurement data of all the inspection areas obtained from the both visual field images, determines the quality of the printed cream solder (ST66), and reports the inspection result (ST67). ), The specimen substrate is removed (ST68).

  FIG. 8 is an overall configuration diagram of a fourth embodiment of the inspection apparatus according to the present invention, in which a substrate 1, a printed cream solder 2, an XY table 3, and two two-dimensional color image sensor cameras 4-1. Since the arrangement of the first hue light source 5-1, the second hue light source 5-2, and the third hue light source 5-3 of the lighting device is the same as that of the third embodiment, the description thereof is omitted. To do.

  8, the two-dimensional color image sensor cameras 4-1 and 4-2 are connected to the control device 6, and the control device 6 includes two two-dimensional sensor imaging units 7 and two image positions. A correction unit 8, a three-dimensional image comparison unit 9, a solder pass / fail judgment unit 10, and an integrated system control unit 11 that controls the entire system, and the units 7 to 11 exchange data through a bus 16.

  The control device 6 includes an input unit 12 for inputting teaching data, an output unit 13 for printing inspection results, a communication unit 14 for transmitting / receiving data to / from an external device, and images and inspection results. Are connected to each other.

  Next, the teaching steps of this embodiment inspection apparatus will be described with reference to the flowchart of FIG. First, the reference board 1 (FIG. 8) on which the cream solder is correctly printed is loaded on the XY table (ST71), the board ID data is taught (ST72), and the inspection area is further taught (ST73). The inspection area is set around a place (called a pad) where the cream solder is printed. This teaching can utilize computer design data of the substrate. Thereafter, the reference substrate is moved by the XY table 3, and the same field of view is simultaneously imaged by the two-dimensional color image sensor cameras 4-1 and 4-2 (ST74). The acquired two images of the reference board are displayed on the corresponding display units 15, respectively, and specific positions in both images are set as position correction marks (ST75). The position correction mark is normally set at a diagonal corner of the substrate, but can also be set in each field of view of the substrate if necessary. Next, the inspection area taught in ST73 is superimposed on the field-of-view image, and the correspondence between the image and the inspection area is confirmed (ST76).

Next, a test substrate is loaded (ST78), moved on the XY table 3, and images of each field of view are simultaneously captured by the two-dimensional color image sensor cameras 4-1 and 4-2 (ST79). Display the field image 2 of the reference board and the field image 2 of the test board on the display unit 15, respectively, and try the difference image processing between the two under the conditions of the default image accuracy and the default detection sensitivity, and miss the defect on the test board. If there is, the image accuracy or detection sensitivity of the inspection region is increased, and if there are many overdetections, those in the inspection region are decreased to adjust the image accuracy and detection sensitivity to be optimal for this substrate (ST80). .
When the adjustment of the image accuracy and detection sensitivity of all the inspection areas is completed and the teaching step is completed, the test substrate is removed (ST81).

As for the image accuracy, it is possible to select whether all pixels in the inspection area are compared or thinned out. When all the pixels are targeted, the inspection accuracy is naturally improved, but the image processing time becomes long. Therefore, a necessary pixel density is applied depending on the type of substrate and the type of defect so that the inspection time can be shortened.
The detection sensitivity of the inspection region is roughly classified into difference sensitivity that raises and lowers the threshold value of the difference image processing, and sensitivity that limits the range of pixel expansion and movement exceeding the threshold value. By detecting the range of different pixels, it is possible to detect not only the protrusion or deficiency of the cream solder printed on the substrate in the planar direction, but also the height defect.
When the difference image processing between the images of the substrates to be compared with the reference substrate is performed, for example, when the height of the cream solder on the sample substrate is higher than that of the sample substrate, as shown in the lower column of FIG. A difference image is obtained, and an imaging inspection about the height is possible.

Next, the automatic inspection operation in this embodiment will be described with reference to the flowchart of FIG.
First, in FIG. 8, the sample substrate 1 is loaded on the XY table 3 (ST91), and when the ID data of the sample substrate is input or read (ST92), the sample substrate 1 is two-dimensionally moved by a command from the control device 6, Under the control of the two-dimensional sensor imaging unit 7, the two-dimensional color image sensor cameras 4-1 and 4-2 simultaneously image each field of view of the specimen substrate 1 (ST93).

  Therefore, the three-dimensional image comparison unit 9 performs differential image processing on the inspection area of the visual field image of the reference substrate and the visual field image of the specimen substrate (ST94), and detects different pixels based on the taught image accuracy and detection sensitivity (ST94). ST95).

  Next, when the solder pass / fail judgment unit 10 integrates the different pixel data obtained from both images, judges the quality of the printed cream solder (ST96), and reports the inspection result (ST97), the sample substrate Is removed (ST98).

  The first and second color image sensor cameras are respectively installed at positions corresponding to the two vertices of the base of an isosceles triangle that is vertically inverted with the substrate surface as a vertex, and the same area of the substrate is inclined to the oblique viewing axis (viewing angle) ), A third hue light source that illuminates the substrate from directly above, and a first that illuminates the substrate from the same direction as the first camera at a position lower than the first camera. The three-dimensional imaging geometric optical arrangement is configured by the hue light source and the second hue light source that is positioned lower than the second camera and illuminates the substrate from the same direction as the second camera, and the automatic solder cream print quality 3 It can be applied to an inspection apparatus that performs a three-dimensional image inspection.

It is explanatory drawing which showed the whole structure of the test | inspection apparatus. Example 1 It is a figure explaining the geometric optical arrangement | positioning and image processing of imaging in a test | inspection apparatus. (All examples) It is the flowchart which showed the operation | movement of the teaching and automatic test | inspection in a test | inspection apparatus. Example 1 It is explanatory drawing which showed the whole structure of the test | inspection apparatus. (Example 2) It is the flowchart which showed the operation | movement of the teaching and automatic test | inspection in a test | inspection apparatus. (Example 2) It is explanatory drawing which showed the whole structure of the test | inspection apparatus. (Example 3) It is the flowchart which showed the operation | movement of the teaching and automatic test | inspection in a test | inspection apparatus. (Example 3) It is explanatory drawing which showed the whole structure of the test | inspection apparatus. (Example 4) It is the flowchart which showed the operation | movement of the teaching and automatic test | inspection in a test | inspection apparatus. (Example 4)

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Board | substrate 2 Cream solder 4 One-dimensional color image sensor camera 5 Illumination device 6 Control apparatus

Claims (4)

A binocular vision system and a substrate stage in which the first color image sensor camera and the second color image sensor camera are opposed to each other above the substrate surface, and image the same region of the substrate looking down at an oblique viewing axis (viewing angle) Imaging means for acquiring both of the three-dimensional images of the substrates by both cameras,
A third hue light source that illuminates the substrate from directly above, a first hue light source that is lower than the first camera and illuminates the substrate from the same direction as the first camera, and a lower position than the second camera A second hue light source that illuminates the substrate from the same direction as the second camera, and illumination means that illuminates the substrate in triplicate with three light sources;
Image position correcting means for correcting the position of both images using a reference point image in each substrate image simultaneously captured by the first camera and the second camera;
Three-dimensional measuring means for measuring a three-dimensional image of the substrate after cream solder printing using images taken by the first camera and the second camera;
An inspection apparatus comprising determination means for performing quality determination of cream solder printing quality using three-dimensional image measurement data. A binocular vision system and a substrate stage in which the first color image sensor camera and the second color image sensor camera are opposed to each other above the substrate surface, and image the same region of the substrate looking down at an oblique viewing axis (viewing angle) Imaging means for acquiring both of the three-dimensional images of the substrates by both cameras,
A third hue light source that illuminates the substrate from directly above, a first hue light source that is lower than the first camera and illuminates the substrate from the same direction as the first camera, and a lower position than the second camera A second hue light source that illuminates the substrate from the same direction as the second camera, and illumination means that illuminates the substrate in triplicate with three light sources;
Image position correcting means for correcting the position of both images using a reference point image in each substrate image simultaneously captured by the first camera and the second camera;
Storage means for storing images captured by both cameras;
Image processing means for performing first difference image processing of the reference substrate image and specimen substrate image captured by the first camera, and second difference image processing of the reference substrate image and specimen substrate image captured by the second camera;
In each of the first difference image processing and the second difference image processing, detection means for detecting a pixel having a difference exceeding a set threshold as a different pixel,
An inspection apparatus comprising integrated determination means for performing quality determination of cream solder print quality in an integrated manner from each detected different pixel.   The color image sensor camera is a one-dimensional color image sensor camera, and the imaging unit moves the binocular vision system or the substrate stage relative to each other in a direction orthogonal to the pixel arrangement of the image sensor, so that both cameras are connected to the substrate 3. 3. The inspection apparatus according to claim 1, wherein each of the dimensional images is acquired.   The color image sensor camera is a two-dimensional color image sensor camera, and the imaging means relatively moves a binocular vision system or a substrate stage so that both cameras acquire a three-dimensional image of the substrate, respectively. The inspection apparatus according to claim 1 or 2.

Images