KR20090080894A - Apparatus and method for appearance inspection of component mounting state - Google Patents

Abstract

An appearance inspection apparatus of component mounting state and an inspection method thereof are provided to inspect an object with high precision as an image scanner focuses on the object through finely controlling vertical gap and tilt. An appearance inspection apparatus of component mounting state comprises an image scanner(2), a unit processing an image and displaying the image on a monitor, a first unit, and a second unit. The image scanner comprises: a reading module(5) moving along one or more guide shafts and projecting an image by positioning an image reading part downward; and a horizontal support member supporting the reading module in the horizontal direction. In the first unit, a transparent cover is installed to be faced to the object and the first unit fine-controls vertical gap and tilt. A second unit fine-controls the flat location and the angle to read inspection image.

Description

Appearance inspection device and inspection method in the state of component mounting {APPARATUS AND METHOD FOR APPEARANCE INSPECTION OF COMPONENT MOUNTING STATE}

BACKGROUND OF THE INVENTION Field of the Invention [0001] The present invention relates to an apparatus for inspecting the appearance of a printed circuit board printed with cream solder, and a method for inspecting the appearance inspection apparatus in an electronic component mounting state.

Conventionally, the method shown in FIG. 15 is performed as a method of printing the cream solder 40 on the printed circuit board 4. The cream solder 40 is a solder containing a metal in a paste state.

The printed circuit board 4 is arrange | positioned under the metal mask 9 in which the some hole 90 and 90 was formed. In one end portion of the metal mask 9, a mass of a paste of cream solder 40 is placed, and the solder 40 is inserted into the hole 90 by a squeegee 91 serving as a pressing plate. The solder 40 in the hole 90 is printed and printed on the frit substrate 4.

As is well known, when the pattern 41 made of copper is formed on the printed circuit board 4, and the solder 40 is printed correctly, the solder 40 is pattern 41 as shown in Fig. 16A. It is placed correctly without exiting. However, if the printed board 4 is warped, or if there is foreign matter or the like below the metal mask 9, a gap is formed, and the solder 40 is pulled out of the pattern 41 as shown in Fig. 16B. If it exits or there is a blockage in the hole 90 of the metal mask 9, as shown in Fig. 16 (c), the solder 40 may be slightly placed on the pattern 41. Since soldering is not performed correctly in this way, there exists a possibility that an electronic component may not be soldered correctly to the printed circuit board 4. In particular, as shown in Fig. 16B, when the solder 40 escapes from the pattern 41, it contacts with the adjacent solder 40, which is a so-called bridge failure.

Then, the apparatus which test | inspects the soldering state on the printed circuit board 4 is conventionally proposed.

17 is a block diagram showing a conventional inspection device 7 (see Japanese Patent Laid-Open No. 6-18237). This photographs the printed board 4 in which the solder 40 was printed on each of the plurality of patterns with the camera 70, and sends the image to the image storage means 71. Next, the binarization means 72 binarizes the image stored by the image storage means 71, and refers to the inspection window frame Q between the plurality of solders 40 and 40 (FIG. 18 (a)). The image in the image) is taken out and binarized. Subsequently, the projection means 73 obtains the projection of the binarized image, and if the value of the projected image shown in Fig. 18B is equal to or greater than the threshold S, then the bridge failure between the solders 40 and 40 is connected. do. These processes and the determination are performed by the control unit 74.

As another conventional example, there is an apparatus for inspecting the soldering state on the printed board 4 using a commercially available image scanner (see Japanese Patent Application Laid-open No. Hei 5-25871). 19 is a cross-sectional view of the image scanner 2. As is well known, the image scanner 2 is provided with a reading module 5 inside which the cover 24 of the upper surface is transparent and which can move left and right along the guide shaft 21. The jig 28 is placed on the cover 24, and the printed circuit board 4 with the solder 40 downward is placed on the jig 28. The reading module 5 scans the image of the solder 40 along the guide shaft 21.

20 is a cross-sectional view showing the inside of the reading module 5. The light from the light 53 shines on the lower surface of the inspection target product (not shown), and the reflected light enters the reading module 5 from the image reading unit 54 whose opening is an opening. The light is reflected by the mirrors 55, 55a, 55b and 55c, and reaches the CCD image sensor 57 through the lenses 56 and 56a to read out the image of the inspection target product.

One end of the reading module 5 moves along one guide shaft 21, and the other end is mounted on a guide (not shown).

As another conventional example, the solder area and the solder deviation may be determined by reading an image by an image scanner and by using a mask processing means for a binary image and a mask image.

There is an inspection apparatus which calculates predetermined coordinates and an area and determines a bridge by mask processing means inverting the binarized image and the mask image (see Japanese Patent Laid-Open No. 2005-156381).

In the said inspection apparatus, there exist the following solutions. First, in the inspection apparatus 7 shown in FIG. 17, the camera 70 image | photographs from the high place of the solder 40. FIG. Thus, the distance between the camera 70 and the solder 40 is actually 30-80 cm apart. By the way, in order to read the image of all the solder 40 and 40 which should be inspected from a high place, resolution is too low and a precise inspection cannot be performed. Therefore, a method of moving the camera 70 or the inspection apparatus from side to side and from side to side and reducing the number of solders 40 and 40 to be inspected at a time is generally performed. In this way, the structure of the inspection apparatus is complicated, and the entire apparatus is expensive.

In addition, in the inspection apparatus shown in FIG. 19, since the printed board 4 is placed on the jig 28, a human hand is needed. Therefore, it is suitable for the inspection process or arbitrary extraction inspection which requires a human hand. However, it is not suitable to convey the printed board 4 automatically and to test the some solder 40 and 40 continuously. The reason is that in the inspection apparatus shown in FIG. 19, it is necessary to place the printed circuit board 4 with the solder 40 downward. By the way, in the state which printed the solder 40, the solder 40 does not harden | cure, but when the solder 40 is made downward, there exists a possibility that the solder 40 may fall down or fall. In addition, there is a fear that dust on the printed board 4 may fall on the image scanner 2 or the transparent cover 24. This becomes an inhibitory factor in image processing, and a problem remains. In order to prevent the solder 40, dust, and the like from falling, a dedicated jig is required separately, which leads to an increase in equipment cost.

In the image processing, Japanese Patent Laid-Open No. 6-18237 discloses that since the inspection range is individually set, it takes too long. In addition, in Japanese Unexamined Patent Application Publication No. 2005-156381, the quality of the solder is determined by the area of the solder. The surface of the solder has irregularities that change every time it is printed, so that the color change is large and dark portions are generated.

In particular, it is difficult to discriminate whether the dark portion is solder or an adjacent resist, and since it changes as described above, the color of the solder cannot be specified. Therefore, it is difficult to accumulate the solder area accurately, and there exists a possibility of causing misjudgement by a solder shortage and misjudgement of a bridge.

Applicant transfers the printed board 4 to the bottom of the image scanner 2 by turning the commercially available image scanner 2 upside down, and continuously inspects the printed board 4 with the solder 40 upward. The device was conceived.

An object of the present invention is to provide an apparatus capable of smoothly inspecting a soldering state at low cost by using the image scanner 2.

The inspection apparatus moves along at least one guide shaft 21, and horizontally supports the reading module 5 for scanning an image to the image reading section 54 downward and the reading module 5 in a horizontal state. An image scanner 2 having a supporting member, a conveying means for conveying an inspection object under the image reading unit 54 of the image scanner 2, and an image scanned by the reading module 5 for processing and monitoring Means for displaying in (11) are provided.

The lower surface of the image scanner 2 is provided with a transparent cover 24 facing the inspection object, and the image scanner 2 has a vertical gap and an inclination to adjust the focal length of the image reading unit 54 and the inspection object. First means for fine adjustment and second means for fine adjustment of the planar position and angle θ for reading out the inspection image are provided.

The inspection apparatus further includes a means for recognizing the pattern of the substrate before solder printing, a means for recognizing the pattern of the substrate after solder printing, and an image of the pattern of the substrate before solder printing and the pattern after the solder printing, and the solder is printed. Means for collectively deleting the pattern other than the inspection target that has not been inspected, and for area integration using the entire pattern after the unprinted solder printing as a master, and means for setting the area ratio which is the criteria for determining the quality of the pattern to be inspected based on the master Equipped,

After setting the area ratio which becomes a determination standard, the remaining area of the post-printing solder pattern which is the inspection object conveyed below the image scanner 2 is calculated | required, and the ratio with respect to the master of the remaining area of the said pattern is a determination reference area ratio It is determined whether the solder is insufficient depending on whether or not it is abnormal.

In addition, the inspection apparatus superimposes the means for noise-processing the pattern image after the solder printing, the noise-processed pattern image and the master image, and whether or not adjacent inspection target patterns are connected or approached by the solder 40, Or means for judging whether the solders 40 are connected or approaching each other, and determining the bridge or bridge start.

1. Since the reading module 5 is supported by one guide shaft 21 and the horizontal support member, it is possible to scan an image even when the image reading unit 54 is directed downward. In addition, since the distance between the transparent cover 24 and the inspection object is secured, the image can be scanned smoothly.

Since the image is scanned from above the inspection object, it is possible to accurately scan the inspection image without dust or the like falling from the inspection object onto the image reading unit 54 or the transparent cover 24.

Since the image scanner 2 focuses by finely adjusting the vertical gap and the inclination, the image scanner 2 can be inspected with high precision.

2. Since the image scanner 2 uses a commercially available product or a part of a commercially available product, the soldering state printed on the upper surface can be automatically and continuously inspected without the need for human hands at low cost.

3. In addition, in the image processing, the inspection apparatus can specify the inspection range in a batch, and the program creation time is also shortened. In addition, since the quality is determined depending on whether the remaining area of the pattern on which the solder is not printed is accumulated and the ratio to the master of the remaining area is equal to or larger than the area ratio that is the determination criterion, determination of solder shortage is also easy. Regardless of the area of the solder 40, this determination simply determines whether adjacent patterns or printed solders are connected by solder, or whether the solder is approaching. Since there are few false judgments, there are few production interruptions and production efficiency is also good. Also in the judgment of a defect, since it is enlarged and displayed on a monitor, the defect location of a board | substrate is also easy to see. Therefore, the determination of good or bad is ensured and feedback is possible in real time.

First embodiment

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. First, the configuration of the inspection apparatus will be described in detail.

1 is a front view illustrating the outline of the inspection device 1, and FIG. 2 is a perspective view of the inspection device 1.

The inspection apparatus 1 is provided on the conveyor belt 32 extended from side to side and intermittently driven, and a plurality of printed boards 4 and 4 to be soldered are placed apart from each other on the conveyor belt 32. The printer 8 is arrange | positioned rather than the inspection apparatus 1 at the conveyor belt 32 upstream. There is a reflow furnace (not shown) which thermosets the electronic component placement machine and solder to the printed circuit board 4 on the downstream side of the conveyor belt 32 rather than the inspection apparatus 1. The conveyor belt 32 of the printing machine 8 and the conveyor belt 32 of the inspection apparatus 1 are minutely separated.

In the printer 8, the printed circuit board 4 is brought into close contact with the metal mask 9, and the cream solder 40 is printed on the pattern of the printed board 4 with the squeegee 91. This process is the same as before.

The inspection apparatus 1 is an image scanner 2 located above the solder printed printed substrate 4 conveyed by the conveyor belt 32, and a personal computer for digitally processing the images of the image scanner 2. (10) "hereinafter referred to as PC 10", the monitor 11 illuminating the image processed by the PC 10, the operator sees the image of the monitor 11, and inputs both parts of solder by hand The keyboard 12 is provided. Digital image processing of the PC 10 will be described later. In addition, the image scanner 2 is a commercial product or a part of commercially available products, and can be obtained at low cost.

On the conveyor belt 32, the stopper 33 which abuts on the downstream end surface of the printed board 4 is provided so that a stopper is possible, and when the printed board 4 is image-scanned by the image scanner 2, the stopper 33 Movement is regulated by After the image operation, the stopper 33 is allowed to move downstream from the printed board 4.

As shown in FIG. 2, a nut 35 is provided on the side of the image scanner 2, and the nut 35 is screwed onto the first screw shaft 30 which is mounted on the frame 3 of the conveyor. . When the first screw shaft 30 is rotated, the image scanner 2 is raised and lowered so as to adjust a distance from the printed board 4 to scan an image. That is, the nut 35 and the first screw shaft 30 constitute an adjusting means for adjusting the distance between the image scanner 2 and the printed board 4 in milli units.

By adjusting the space | interval of the image scanner 2 and the printed board 4, not only the soldering state of the printed board 4 but also the state which mounted and soldered the electronic component to the printed board 4 can be examined.

FIG. 3 is a bottom view of the image scanner 2, and FIG. 4 is a cross-sectional view of FIG. 2 broken at the plane including the A-A line. The image scanner 2 has a drive belt installed inside the cabinet 20 with a reading module 5 movable left and right along two spaced guide shafts 21 and 21 and connected to the stepping motor 22. The read module 5 is driven by the reference numeral 23. The reading module 5 is horizontally supported by the two guide shafts 21 and 21, is fitted in one guide shaft 21 with a small margin, and is mounted on the other guide shaft 21. It is fitted with room to spare. The lower surface of the image scanner 2 is covered with a transparent cover 24. Alternatively, in place of the transparent cover 24, a transparent cover for preventing dust (not shown) may be disposed on the reading part.

In the present example, unlike the use of the normal image scanner 2, the image reading section 54 is directed downward. Since the scanning operation of the reading module 5 is controlled by the control circuit 29 and the reading module 5 is fitted to the two guide shafts 21 and 21, even if the image scanner 2 is inverted up and down, Can be used.

Two conveyor belts 32 and 32 are spaced apart from each other in accordance with the width length of the printed board 4. Each conveyor belt 32 is accommodated in a belt stand 34, and each belt stand 34 is screwed onto a second screw shaft 31 provided between the frames 3, 3. By rotating the second screw shaft 31, the distance between the conveyor belts 32 and 32 can be adjusted.

(Inspection procedure)

The inspection procedure will be described below. The printed circuit board 4 on which the cream solder 40 is printed by the printer 8 is placed on the belt 32, stopped by the stopper 33, and positioned below the image scanner 2. The vertical gap between the image reading unit 54 and the transparent cover 24 of the image scanner 2 and the printed board 4 is adjusted by rotating the first screw shaft 30 in advance, and in this example, the number of 1 cm or less About a millimeter. In addition, it is not limited to this dimension.

The spacing of several milliseconds between the image reading unit 54 or the transparent cover 24 and the printed board 4 is based on the following reasons (1)-(4).

(1) Since the cream solder 40 is not cured yet, when the image reading unit 54 or the transparent cover 24 and the printed circuit board 4 are in contact with each other, the cream solder 40 causes the image reading unit 54 or the transparent cover ( It may be attached to 24).

② If there is no gap, the printed board 4 cannot be conveyed correctly by the belt 32.

(3) In the image scanner 2, an image cannot be scanned accurately unless there are several millimeters of gaps between the printed circuit board 4 as an inspection object.

(4) The focal length of the image reading section 54 is about 8 mm, and the image cannot be scanned accurately without the gap.

When the reading module 5 of the image scanner 2 is moved left and right, the image of the solder 40 of the printed circuit board 4 is read, the image is processed by the PC 10, and it is determined that it is a defect, and the monitor 11 ). When the operator sees the image of the monitor 11 and judges the true quality of the solder printing, and judges it as "good", the worker moves the belt 32 to move the next printed board 4 to the image scanner 2. Move to the bottom of. When it determines with "part", ie, a defective product, the printed board 4 is taken out. In this case, the stopper 33 is not released and the image of the monitor 11 is not updated until the printed board 4 is taken out.

The data processed by the PC 10 to determine the quality of the data, the customer name of the printed circuit board 4, the inspection target item name, the date, the inspection method, and the like are all stored in the PC 10 as information. It is desirable to use this information for future production. In addition, in the display on the monitor 11, the part to be determined may be automatically enlarged and displayed to facilitate the determination. In addition, in order to feed back a determination of "part" to the previous process, the "part" position on the printed circuit board 4 may be reduced in size to easily confirm the position. These settings can be handled by software in the PC 10.

The configuration for supporting the reading module 5 horizontally is not limited to the above two guide shafts 21 and 21. For example, as shown in FIG. 5, one guide shaft 21 supports one end of the reading module 5 and protrudes the protruding piece 58 from the other end of the reading module 5. The base piece 25 may protrude from the inside of the cabinet 20 of the image scanner 2, and the bottom piece of the protruding piece 58 may be received by the base piece 25. In addition, as shown in FIG. 6, two protrusion pieces 58 and 58a may be spaced apart up and down, and the lower surface of the upper protrusion piece 58 may contact the upper surface of the base piece 25. As shown in FIG. . In this case, there may be a gap between the lower projecting piece 58a and the lower surface of the supporting piece 25. That is, the space between the protrusions 58 and 58a is not required to be accurate, and hence the cost can be suppressed. As shown in FIG. 7, the upper protrusion piece 58 may be received as the guide shaft 21.

In addition, as shown in FIG. 8, the supporting member 26 is provided on the transparent cover 24, and the supporting member 26 of the protruding piece 58 protrudes from the other end of the reading module 5 to the supporting member 26. You can also receive. 5 to 8, the drive belt 23 is not shown.

In addition, as described above, a gap of several millimeters needs to be provided between the transparent cover 24 and the printed board 4. In the above, a gap is formed between the transparent cover 24 and the printed circuit board 4 by the adjusting means composed of the nut 35 and the first screw shaft 30, and instead shown in FIG. 9. The configuration may be.

9 is a side sectional view of an image scanner 2 showing another embodiment, and a spacer 6 is provided between the frame 3 of the conveyor and the transparent cover 24 of the image scanner 2. As a result, a gap may be formed between the transparent cover 24 and the printed circuit board 4. The spacer 6 may be mounted on the bottom surface 69 through the frame 3, as indicated by a dashed-dotted line in FIG. 9.

10 is a front sectional view of the image scanner 2 showing another embodiment. As in FIG. 9, a spacer 6 is provided between the frame 3 of the conveyor and the transparent cover 24 of the image scanner 2. However, unlike FIG. 9, in FIG. 10, the lower end of the image scanner 2 is pivoted to the spacer 6 on the left side. By the structure shown in FIG. 10, after completion | finish of an inspection, the image scanner 2 can be rotated upwards centering | focusing on the pivot 60, and the tested printed circuit board 4 can be taken out from the top. However, it is not limited to this. Thereby, the downstream conveyor and stopper 33 become unnecessary, and installation cost can be reduced.

Alternatively, the slide guides may be attached to both sides of the image scanner 2 (not shown), and after completion of inspection, the image scanner 2 may be slid inward to pull out the printed board 4.

Second embodiment

11 is a plan view of the image scanner 2 according to another embodiment. In a typical commercial scanner, the maximum reading is A4 size (21 cm x 30 cm), and when the size of the printed board 4 is A4 size, the scanning time is increased. In this example, three reading modules, that is, the first reading module 5, the second reading module 50, and the third reading module 51 are provided in the image scanner 2. For convenience of illustration, the guide shafts 21 and 21 are not shown. The area upstream of the printed board 4, that is, 1/3 of the area from the right, is image scanned by the first reading module 5, and the area downstream of the printed board 4, that is, 1/3 from the left, is The image is scanned in the second reading module 50. That is, in FIG. 12, the area X is image scanned in the first reading module 5, and the area Y is image scanned in the second reading module 50. That is, in the 1st, 2nd reading module 5 and 50, the area | region Z of the longitudinal center part of the printed circuit board 4 is not image-scanned. At this time, in the printed circuit board 4 located on the downstream side of the printed board 4, the third region Z of the remaining third is scanned by the third reading module 51. By this method, contact between the first and second modules 5 and 50 can be avoided.

Next, the stopper 33 is released and the printed circuit board 4 is sent to the third reading module 51. In the third reading module 51, the area Z is image scanned. In this example, since the three read modules 5, 50 and 51 scan the image of the solder 40, the time for scanning can be shortened. That is, since the inspection target surface is divided and the inspection target surface divided by the respective reading modules 5 (50) and 51 is read out, the time for image scanning can be shortened.

FIG. 13A is a plan view showing the positional relationship of the first to third reading modules 5 and 50 and 51 for scanning the printed boards 4 of different sizes. The size of the printed circuit board 4 is about 2/3 of the said longitudinal direction, and in this case, between the right end part of the printed board 4 shown by V in FIG. 13, and the 1st reading module 5, The image is not scanned. However, the point where the left end part of the printed board 4 is scanned by the 2nd reading module 50 and the longitudinal center part of the printed board 4 in the 3rd reading module 51 is image-scanned is the same as the above. .

In addition, the horizontal and vertical size of the printed circuit board 4 is not limited to said A4 size, The size may be longer than the A4 size. For example, when the width is longer than A4, the above-described FIG. 11 can be applied. In addition, when length is long, what is necessary is just to arrange | position the some reading module 5 and 5 which scan orthogonally with respect to the conveyor belt 32, as shown to FIG. 13 (b).

Third embodiment

14 is a plan view of the image scanner 2 according to another embodiment. In this example, a plurality of ten vertical read modules 52 and 52 are arranged in FIG. 14, and the vertical read modules 52 and 52 do not move. Instead, the printed board 4 on the conveyor belt 32 moves. In the inspection of damage, dirt, dust and patterns of the printed circuit board 4, it is necessary to inspect at a high resolution of about 5-10 microns, which takes a considerable time. Therefore, compared with the horizontal type, many vertical reading modules 52 and 52 which have a small planar area are arranged, the inspection surface is divided, the movement distance of the printed circuit board 4 is also short, and the scanning time was shortened. In addition, the number of the vertical read modules 52 and 52 is not limited to the number shown in FIG.

Fourth embodiment

Fig. 26A is a side sectional view of an image scanner of another embodiment, and Fig. 26B is a flat view thereof. A protective cover 200 is mounted outside the image scanner 2, and a lower surface of the protective cover 200 is covered with a transparent cover 24. The stay 300 is covered on the outside of the image scanner 2, and the lower end of the stay 300 is mounted to the frames 3 and 3 of the conveyor with screws 310. The ceiling surface of the stay 300 and the upper surface of the protective cover 200 are connected by two first adjustment screws 210 and 210 spaced apart along the width direction of the image scanner 2, and the image scanner 2 is connected. The vertical space | interval and the inclination (theta) 1 of the reading module 5 in the inside and the printed circuit board 4 which are the test object are adjusted by rotating the 1st adjustment screw 210 and 210. FIG. That is, the first adjustment screws 210 and 210 are used to finely adjust the vertical gap and the inclination θ1 to adjust the focal length of the image reading unit 54 of the reading module 5 and the inspection object. Configure the means.

However, the first adjustment screw 210 is screwed with a margin to the ceiling surface of the stay 300, and allows the shaking in the minute plane direction. On the side surface of the stay 300 and the side surface of the protective cover 200, the second adjusting screws 220 and 220 are screwed, and by rotating the second adjusting screws 220 and 220, the reading module ( The plane position and angle [theta] 2 of 5) are adjusted. In other words, the second adjustment screws 220 and 220 constitute second means for adjusting the planar position and the angle θ2 of the image reading unit 54 of the reading module 5.

The reading module 5 can scan approximately parallel along the direction of movement of the conveyor belt 32. If the length of the printed board 4 is A4 size (21 cm x 30 cm) or less, the image is read by one scan. However, when the length of the printed board 4 is exceeded, the scan is divided into two. On the frame 3, along the conveyance direction of the conveyor belt 32, the 1st stopper 320 and the 2nd stopper 330 are provided. The 1st stopper 320 and the 2nd stopper 330 can raise and lower toward the printed circuit board 4, and when the printed circuit board 4 does not oppose the reading module 5, it will raise.

When the length of the printed board 4 exceeds A4 size, as shown in FIG. 26 (c), first, the first stopper 320 is placed on the side surface of the printed board 4 to convey the printed board 4. The first half A1 along the direction is scanned. Thereafter, the abutment between the first stopper 320 and the printed circuit board 4 is released, and as shown in FIG. 26 (d), the printed circuit board 4 is positioned on the transport side of the printed circuit board 4. It is conveyed to the second stopper 330. Thereafter, the remaining rear portion B1 region is scanned.

In general, the reading module 5 of the commercially available image scanner 2 can scan only up to A4 size. However, in this example, even if the width | variety length of the printed circuit board 4 exceeds A4 size, it can read up to about 60 cm by dividing into two and scanning.

Fifth Embodiment

FIG. 27A is a side sectional view of an image scanner of another embodiment, (b) is a plan view thereof, and (c) and (d) are plan views illustrating a scanning operation of the reading module 5. In this example, the scanning direction of the reading module 5 is substantially orthogonal to the conveyance direction of the printed board 4. The structure which provided the 1st adjustment screw 210 (210) and the 2nd adjustment screw 220 (220) is the same as that of the Example shown in FIG.

In this example, the reading module 5 can scan approximately orthogonally in the moving direction of the conveyor belt 32. On the stay 300, a protective cover 200 is fitted and the image scanner 2 is suspended from the stay 300 downward. In one scan of the reading module 5, only the printed circuit board 4 having a length of about 21 cm can be read. However, by conveying the printed board 4 and reading it again, that is, scanning twice, the printed board 4 can be read up to about 30 cm in length and about 40 cm in width.

(First example of inspection image processing)

An example of digital image processing and determination means of the PC 10 after being read by the image scanner 2 will be described in detail. Other examples will be described later.

FIG. 21 is a schematic plan view of the substrate before solder printing, showing the pattern 41 to be solder printed on the printed board 4 and the non-solder printed pattern 41a. In addition, A and B are semiconductors, C is a chip, and is an electronic component mounted later. D is a soldering prevention resist plating film. The resist is generally green and is applied thinly over the entire surface except for the patterns 41 and 41a. The non-solder pattern 41a is, for example, a pattern for attaching solder by hand in a later step.

FIG. 22 shows a pattern state in which solder 40 is printed on the pattern 41 to be solder printed on the printed board 4 of FIG. 22, the solder 40 is covered on the pattern 41, and the pattern 41 is covered. On the other hand, it shows the state in which only the pattern 41a which is not solder printed exists.

In the PC 10, the patterns 41 and 41a of the substrate before solder printing shown in Fig. 21 are extracted, and then the pattern images subjected to binarization and noise processing are recognized. Next, the color of the solder on the substrate after the solder printing shown in Fig. 22 is extracted, and the pattern image after the printing of the binary 40 and soldered solder 40 is recognized. In this case, however, the monitor 11 enlarges and confirms whether or not printing is performed correctly. Naturally, if there is a problem, fix it again. In the case of accurate printing, it conveys downstream after the said image recognition. Next, the image of the pattern 41 (41a) shown in FIG. 21 and the pattern image after the printing of the solder 40 are superimposed to collectively delete the pattern 41a other than the inspection target on which the solder 40 is not printed.

Accordingly, only the pattern 41 to which the solder is to be printed exists. The total area of each pattern 41 is integrated, and this is used as a master. Next, based on the said master, the area ratio used as the reference | standard of the quality judgment of the pattern 41 which is a test object is set. This area ratio indicates the permissible range of the area of the pattern 41 left without solder printed on the entire area of the pattern 41. The integrated area and the area ratio are stored in the PC 10, and after setting the area ratio, the area of the pattern 41 which is the inspection target conveyed to the lower side of the image scanner 2 is obtained.

(A), (b), (c), (d) shows the state in which the solder 40 was printed on a part of the pattern 41 in the test substrate after solder printing. The area of the remaining pattern 41 is removed by the master, and the ratio of remaining pattern 41 is obtained. When the pattern 41 remains beyond the area ratio used as the basis of the acceptance judgment, it is determined that the solder is insufficient.

That is, a solder shortage is determined according to whether the remaining area of the pattern 41 after solder printing is more than the area ratio which is a criterion of determination.

For example, as shown in Fig. 23A, when the solder 40 is not printed on the entire surface of the pattern 41, the pattern 41 remains. When the reference area serving as a criterion for determining the quality of the pattern 41 is set to 20% or less, only the solder 40 is printed on the pattern 41 of FIG. Since the remaining area of) is 20% or more of the entire area of the pattern 41, it is regarded as a solder shortage.

In FIG. 23B, the solder 40 is correctly printed on the entire surface of the pattern 41, and the remaining area of the pattern 41 is 0%, and is 20% or less, so it is determined as good quality.

With the unevenness of the solder 40, even if a shadow exists, the pattern 41 under the shadow is hidden from view, so that determination of the lack of solder is not affected. That is, as shown in Fig. 23C, even in an area 40D in which the boundary between the resist and the solder 40 is ambiguous, the pattern 41 under the cover is obscured, and the portion where the pattern 41 is exposed is 20% or more. If so, it can be determined that the solder is insufficient. On the contrary, in FIG. 23 (d), since the pattern 41 is covered by the obscure area 40D and is not seen at all, it can be seen that solder printing is good.

In general, image processing extracts the color of the inspection object and specifies the color distribution and brightness of the inspection object in red green blue (RGB) corresponding to three primary colors of light. Thereafter, a binarization process and a noise process which are generally performed are performed. By the way, there exists a possibility that the solder 40 may change color for every printing, and light may reflect irregularly, RGB may stain, and it may be difficult to identify it as the color of the solder 40. FIG. In this example, the area of the pattern 41 without color change is calculated. By this means, misjudgment of a shortage of solder is reduced.

The surface of the printed solder 40 has a large unevenness and a large change in color compared with the copper pattern 41 due to the size of the solder particles, printing irregularities, and the like. When extracting the color of the solder, there is a fear that the boundary between the resist and the solder 40 may be inaccurate due to some mixing with the color of the resist. In image reading in the image scanner 2, this tends to be particularly true. Therefore, there exists a possibility that the determination of a solder area may lack accuracy. In view of this, the present invention has decided to integrate the area of the pattern 41 with relatively few irregularities. By this means, there is little misjudgment of a lack of solder.

FIG. 24 (a) overlaps the pattern image after the solder 40 which has been subjected to the noise processing after the binarization process and the image of the pattern 41 which is the master, and the adjacent patterns 41 and 41 are solder 40 to each other. Indicates the bridge state connected by. Recognizing the connection state, it is determined whether the bridge state. In the present example, as shown in Fig. 24B, even if the boundary line between the resist and the solder 40 is inaccurate and ambiguous, the adjacent patterns 41 and 41 are soldered as shown. It is only possible to recognize whether it is connected or approached by the 40, or whether the solders 40 are connected or approached by the solders 40, and can be determined simply. Therefore, there is little misjudgment of a bridge.

As mentioned later, what formed the pattern of the board | substrate before solder printing and the image 95 of the film 96 by overlapping may be used for the master.

24C shows the bleeding state of the solder 40. The bleeding of the solder 40 is attracted to the pattern center part by the surface tension of the solder at the time of solder melt | dissolution, and as shown in FIG. 24 (d), a bleeding decreases or disappears in many cases. This phenomenon tends to attract the solder because the resist coating film is present between adjacent patterns. However, when the adjacent patterns 41 and 41 are connected by the solder 40, the solders 40 of the patterns 41 and 41 are attracted to each other and soldered with the bridge present.

Conventionally, even if the spreading of the solder 40 spreads beyond a predetermined coordinate range, the connection may not be performed, and there is a fear of misjudgment by the bridge. In this example, it recognizes only whether the adjacent patterns 41 and 41 are connected or approached by the solder 40, and there is no fear of misjudgment.

Also, as shown in Figs. 25A and 25B, even in the case of solder printing, if the remaining area of the pattern 41 is within the range of the area ratio which is the criterion of determination, it is determined to be good or out of quality. do. Even if it is in the said range, when connected by the said solder 40, since it determines with a bridge, there is no worry.

If the distance between adjacent solders 40 and 40 is equal to or less than a certain length, there is a risk of bridging. In other words, when components are mounted in the cream solder 40 and 40, the solder 40 and 40 may be pushed out from the patterns 41 and 41. FIG. If the adjacent patterns 41 and 41 or the solders 40 and 40 are very close, the solders 40 and 40 may be connected. Therefore, when the adjacent patterns 41 and 41 or the solder 40 and 40 approach extremely, there is a fear of bridge (called bridge start), and therefore, it is determined as defective.

When all the test | inspection of a test | inspection board | substrate is complete | finished and it is determined as a quality goods, the said board | substrate is conveyed downstream. Specifically, the stopper 33 is released, and a signal of a command for driving and conveying the conveyor belt 32 is sent from the PC 10 to the control device.

If there is a defect, the transfer command signal is not sent, and the stopper 33 is not released. The defective part is enclosed by a red frame in the monitor 11, and the enlarged display is shown, and the whole board | substrate and the position of the defective part reduced in the corner part of the monitor 11 are image-displayed. The worker sees the image and makes a judgment. When judging as a good product, the OK button of the keyboard 12 is operated to convey a board | substrate downstream. In addition, when it determines with defect, a board | substrate is taken out. Moreover, since a defective part is known, it feeds back. That is, the printer 8 is corrected or the metal mask 9 is cleaned to remove the cause of the defect.

(Second example of inspection image processing)

As described with reference to FIG. 15, when printing the cream solder 40 on the printed board 4, it is necessary to prepare a metal mask 9 in which a plurality of holes 90 and 90 are formed. Data of the position and size of the holes 90 and 90 of the metal mask 9 can be inserted into the PC 10 as photo data. The photo data does not contain data of the pattern 41a which is not solder printed. In this example, by using this photo data, the pattern 41a other than the inspection target which is not covered with the solder 40 is collectively deleted. That is, in the first example of the inspection image processing, the pattern images 41 of the substrate after solder printing are superimposed on the patterns 41 and 41 a of the substrate before solder printing, and the pattern 41a other than the inspection object is deleted. In this example, the photo data is overlaid on the patterns 41 and 41a of the substrate before solder printing in place of the pattern image 41 of the substrate after solder printing.

As shown in Fig. 28A, an image 95 of a hole 90 is generated based on the photo data, and the image is printed on the upper surface of the transparent film 96. The reference mark 99 is provided on the film 96, and the same reference mark is provided in the four corners of the board | substrate 4 before solder printing. After the image 95 of this film 96 is read by the image scanner 2 from the film 96, it is overlaid on the board | substrate 4 before solder printing, and the reference mark 99 is matched with each other.

Thereby, the image 95 of the film 96 is correctly covered by the pattern 41 (41a) of the board | substrate before solder printing, and the pattern 41 to be solder-printed is covered up. The pattern 41a other than the inspection object in which the solder 40 is not covered is collectively deleted.

As a result, an image in which only the inspection target pattern 41 to be solder-printed is produced. The total area of each pattern 41 is integrated, and this is used as a master. Next, based on the said master, the area ratio used as the reference | standard of the judgment of the pattern 41 is set to 20%, for example.

Next, the pattern 41 image of the printed circuit board 4 after solder printing to be inspected is read by the image scanner 2, and the area of the pattern 41 on which solder is not printed is obtained. The area of this pattern 41 is removed by a master, and the ratio which remains of the pattern 41 is calculated | required. When the pattern 41 remains beyond the area ratio used as the basis of the acceptance judgment, it is determined that the solder is insufficient. Specifically, when the pattern 41 remains above 20% which is the area ratio, it is determined that the solder is insufficient. If the area where the pattern 41 remains is 20% or less which is an area ratio, it is determined as good quality.

As shown in FIG. 28 (b), when the image 95 of the film 96 is read by the reading module 5, light is transmitted on the film 96, so that the shade 97 of the image 95 is applied. ) May enter. Since the film 96 has a thickness, the shade 97 is pushed in a planar position with respect to the image 95. Since the inspection of the pattern 41 examines about 20-40 microns of jungle, the influence of the jungle of this planar position is large.

Therefore, first, the image of the photo data in the PC 10 is mirror-inverted and printed on the film 96. As shown in Fig. 28 (c), the printed image 95 is inverted up and down so as to become the ceiling surface of the film 96, and the image 95 is read so that no shadow is entered. I can do it. In addition, when reading the image 95 of the film 96 inverted up and down, if the white plate 98 is laid under the film 96, it can prevent reading an unnecessary image, noise, etc.

(Third example of inspection image processing)

As in the related art, the patterns 41 and 41a are generally made of copper. In recent years, the patterns 41 and 41a made of gold may be used in consideration of the low resistance value and the ease of soldering. . When light is irradiated from above the gold patterns 41 and 41a and the image of the patterns 41 and 41a is read by the reading module 5, there is also a color contained in the solder 40 itself. There is a fear that the 40 and the patterns 41 and 41a cannot be identified.

In addition, the solder 40 has an obscure part due to the surrounding color, shadow, or the like. Applicant has paid attention to the specific color of the solder 40 in view of this point. That is, RGB, which is a solder specific color that does not include the resist adjacent to the solder 40 or the color of the patterns 40 and 40a, is extracted, and the solder specific color dotted in the solder 40 is connected to the solder ( 40) specifies the printed area.

Specifically, as illustrated in FIG. 29, the binary image of the solder 40 read by the reading module 5 causes the element 46 of the specific color of the solder to be black compared with the surroundings. . The area in which the solder 40 is printed is estimated by enclosing all the elements of the solder specific color illuminated black compared with the surroundings by the virtual frame 45 represented by a single-dot chain line. The area in this virtual frame 45 is removed by the master, and the ratio which the solder 40 is printed is calculated | required. In the PC 10, an area ratio serving as a standard for determining whether the solder 40 is printed is set in advance.

If the ratio of the area in the virtual frame 45 is less than or equal to the area ratio, it is determined that the solder is insufficient. When the ratio of the area in the virtual frame 45 exceeds the area ratio, it determines with good quality.

In the above example, the inspection apparatus for confirming the printing state of the solder 40 of the printed board 4 is disclosed, but the state of mounting the electronic component on the printed board 4 or the state of the solder hardened by reflow is inspected. You may also Here, the soldering state to be examined includes the presence or absence of soldering, underscore, bridges and the like. In addition, the mounting state of the electronic component to be inspected includes the presence or absence of an electronic component, a positional shift, an error of the electronic component itself, and an error of polarity.

It is suitable for inspecting the printed circuit board 4 in which the electronic component, specifically, the thin electronic component used for a mobile phone, a digital camera, etc. is mounted, and the vertical space | interval of the printed circuit board 4 and the image reading part 54 is an image reading. The focusing distance of the part 54 is adjusted to about 7-9 mm. The first means for finely adjusting the vertical space and the inclination θ1 and the second means for adjusting the plane position and the angle θ2 of the image reading unit 54 adjust the focal length and read the image accurately. To enter, it is indispensable. In addition, a reflecting plate (not shown) may be provided in the reading unit 54 of the image scanner 2 so as to brighten the image of the surface facing the illumination.

In addition, you may use the test | inspection apparatus of this example for the test | inspection of the shape of the hole 90 of the metal mask 9, a positional precision, and the presence or absence of the adhesion of the solder debris around the hole 90. In addition, you may test the precision of a board | substrate before printing.

1 is a front view showing an outline of an inspection apparatus;

2 is a perspective view of the inspection device,

3 is a bottom view of the image scanner,

4 is a cross-sectional view taken from the plane including the line AA in FIG. 2;

5 is a side cross-sectional view showing another configuration of horizontally supporting the reading module;

6 is a side cross-sectional view showing another configuration of horizontally supporting the reading module;

7 is a side cross-sectional view showing another configuration of horizontally supporting the reading module;

8 is a side sectional view showing another configuration of supporting the reading module horizontally;

9 is a cross-sectional side view of an image scanner of another embodiment;

10 is a front sectional view of an image scanner showing another embodiment,

11 is a plan view showing an image scanner according to another embodiment;

12 is a plan view showing a divided inspection target surface;

13 is a plan view showing an image scanner in another embodiment;

14 is a plan view showing an image scanner in another embodiment;

15 is a plan view showing a method of printing a cream solder on a conventional printed board;

16A, 16B, and 16C show cream solder printed on a pattern;

17 is a block diagram showing a conventional inspection device;

(A), (b) is a figure which shows the inspection principle of the inspection apparatus of FIG.

19 is a sectional view of an image scanner,

20 is a sectional view showing the inside of a reading module;

21 is a plan view showing a printed circuit board before solder printing;

22 is a plan view showing a printed circuit board after solder printing;

Fig. 23 is a diagram showing a state where solder is printed on a part of a pattern on a printed board after solder printing;

24 (a) and 24 (b) are plan views showing a bridge state, (c) and (d) are plan views showing a bleeding state of solder;

25 (a) and 25 (b) are plan views showing the solder printing rolling state,

(A) is a side sectional view of an image scanner of another embodiment, (b) is a plan view thereof, (c), (d) is a plan view showing a scanning state of the image scanner,

27A is a side sectional view of an image scanner of another embodiment, (b) is a plan view thereof, (c), (d) is a plan view showing a scanning state of the image scanner,

28A, 28B, and 28C are explanatory diagrams showing examples of inspection image processing;

Fig. 29 is a plan view showing a virtual frame surrounding the entire solder specific color elements.

Claims (14)

A reading module 5 which moves along at least one guide shaft 21 and scans an image with the image reading section 54 facing downward, and a horizontal supporting member which supports the reading module 5 in a horizontal state. An image scanner 2, a conveying means for conveying an inspection object under the image reading unit 54 of the image scanner 2, and an image scanned by the reading module 5 for processing the monitor 11 Install means to display on, The lower surface of the image scanner 2 is provided with a transparent cover 24 facing the inspection object, and the image scanner 2 has an upper and lower interval and an inclination (to adjust the focal length of the image reading unit 54 and the inspection object). 1st means which fine-adjusts (theta) 1), and 2nd means which fine-adjusts the plane position and angle (theta) 2 for reading out a test image, The inspection apparatus characterized by the above-mentioned. The method according to claim 1, First and second means are installed via the stay (300). The method according to claim 1 or 2, The image scanner 2 is installed to be rotatable upwardly or slidably inward with respect to the pivot 60, and after completion of inspection, is rotated upwards or slides inwardly to pull out the printed board 4. Opened, inspection device. The method according to any one of claims 1 to 3, The first stopper 320 and the second stopper 330 for stopping the inspection object are provided along the conveying direction of the inspection object, and the inspection object stopped by the first stopper 320 by one reading module 5. An inspection apparatus for scanning the front end portion and the rear end portion of the inspection object stopped on the second stopper (330). The method according to any one of claims 1 to 4, In the image scanner (2), a plurality of reading modules (5) are provided, and the inspection apparatus which divides and reads the inspection surface of a test object. The method according to any one of claims 1 to 5, The inspection object is an inspection apparatus which is a solder (40) or a pattern (41) printed on a printed board (4). The method according to claim 6, Means for recognizing the pattern of the substrate before solder printing, Means for recognizing the pattern of the substrate after solder printing, and patterns other than inspection targets in which an image of the pattern of the solder pre-printed substrate and the pattern after the solder printing is superimposed and the solder is not printed And a means for integrating the area using the entirety of the pattern after the unprinted solder printing as a master, and means for setting an area ratio that becomes a criterion for determining the quality of the pattern to be inspected based on the master. , After setting the area ratio which becomes a determination standard, the remaining area of the pattern after solder printing which is the inspection object conveyed below the image scanner 2 is calculated | required, and the ratio with respect to the master of the remaining area of the said pattern becomes a determination standard The inspection apparatus which determines a solder shortage according to whether it is more than an area ratio. The method according to claim 6, Means for recognizing the pattern of the substrate before solder printing; means for recognizing the image 95 of the film 96 created by using photo data in which the area to be solder printed is set; and the pattern and the film 96 of the substrate before solder printing. Means for overlapping the images 95 of the film 96 and collectively deleting the patterns other than the inspection object not covered with the image 95 of the film 96, and integrating the area using the entire undeleted patterns as a master and the master A means for setting an area ratio that serves as a criterion for quality determination of the inspection target pattern; After setting the area ratio which becomes a determination standard, the remaining area of the pattern after solder printing which is the inspection object conveyed below the image scanner 2 is calculated | required, and the ratio with respect to the master of the remaining area of the said pattern becomes a determination standard The inspection apparatus which determines a solder shortage according to whether it is more than an area ratio. The method according to claim 8, And the image (95) is formed on the lower surface of the film (96). The method according to claim 6, Means for recognizing the pattern of the substrate before solder printing, Means for recognizing the pattern of the substrate after solder printing, and patterns other than the inspection targets not covered with solder by superimposing images of the pattern of the solder before printing and the pattern after solder printing Means for collectively deleting and area-integrating the undeleted pattern image as a master, After area integration, the solder specific color is extracted from the solder print area on the pattern to be inspected and conveyed to the bottom of the image scanner 2, and the solder print area is extracted from the virtual frame 45 surrounding the portion of the solder specific color. An inspection apparatus which estimates an area and determines a solder shortage from the ratio of the estimated area of the solder print area to the area of the master. The method according to claim 6, Means for recognizing the pattern of the substrate before solder printing; means for recognizing the image 95 of the film 96 created by using photo data in which the area to be solder printed is set; and the pattern and the film 96 of the substrate before solder printing. Means for superimposing the images 95), and collectively deleting the patterns other than the inspection targets not covered with the images 95 of the film 96, and integrating the area using the entire undeleted patterns as a master, After area integration, the solder specific color is extracted from the solder print area on the pattern to be inspected and conveyed to the bottom of the image scanner 2, and the solder print area is extracted from the virtual frame 45 surrounding the portion of the solder specific color. The inspection apparatus which estimates an area and determines a solder shortage from the ratio of the estimated area of the solder print area and the master area. The method according to claim 7 or 10, The means for noise-processing the pattern image after the printing of the solder 40, the noise-processed pattern image, and the image of the master are superimposed and the adjacent inspection target patterns 41, 41 or solders 40 and 40 are soldered together. Means for making a determination as to whether connected by or approaching, and determining a bridge or bridge initiation. The method according to any one of claims 8, 9 or 11, The pattern of the substrate before solder printing, the image of the master formed from the image 95 of the film 96, and the pattern after the printing of the solder 40 are superimposed, and the adjacent inspection target patterns 41, 41 or solder 40 ( 40) An inspection apparatus, comprising means for judging whether or not they are connected by solder or approaching each other, and determining a bridge or a bridge start. A reading module 5 which moves along at least one guide shaft 21 and scans an image with the image reading section 54 facing downward, and a horizontal supporting member which supports the reading module 5 in a horizontal state. A conveying means for conveying the provided image scanner 2, the substrate 4 having a pattern on which the solder 40 is printed below the image reading unit 54 of the image scanner 2, and a reading module. An inspection method using an inspection apparatus provided with means for processing and displaying an image scanned by (5) on the monitor 11, A process of conveying the board | substrate 4 below the image reading part 54 of the image scanner 2 by a conveying means, A process in which the reading module 5 scans an image from above the substrate 4, Recognizes the pattern of the substrate before solder printing, recognizes the pattern of the substrate after solder printing, overlaps the image of the pattern before the solder printing and the substrate pattern after solder printing, and collectively deletes the pattern outside the inspection target where the solder is not printed. And a step of area integration using the pattern image after solder printing not deleted as a master; A step of setting an area ratio serving as a criterion for determining whether the pattern to be inspected is based on the master; After setting the area ratio, the remaining area of the pattern after solder printing, which is the inspection object conveyed under the image scanner 2, is obtained, and the ratio to the master of the remaining area of the pattern is equal to or larger than the area ratio serving as a criterion of determination. Depending on whether or not to determine a solder shortage, Superimposing a pattern image after solder printing and an image of a master, and determining whether adjacent inspection target patterns 41, 41, or solders 40, 40 are connected or approached by solder; , An inspection method comprising the step of processing the scanned image and displaying it on the monitor (11).

Images