JPH05138859A - Apparatus for inspecting printing condition of paste solder - Google Patents

Abstract

PURPOSE:To apply fast processing only to the part judged to be not good by a wide visual field judging part by judging the part by a micro visual field judging part by mounting wide and micro visual field lattice projection parts, wide and micro visual field judging parts and a substrate moving part corresponding to wide and micro visual field imaging devices different in imaging magnification. CONSTITUTION:A micro visual field imaging device 12 takes the image of the printed circuit board attached to a board moving part 13 moved to the reference position within a visual field and a micro visual field judging part 36 operates the reference position of the printed circuit board to send out the operation result to a main control part 37 as a correction value of an inherent error. Next, the main control part 37 refers to the correction value to position the first area to be imaged among a plurality of divided areas to be imaged within the visual field of a wide visual field imaging device 11 and the image of said area is taken through a predetermined lattice pattern by a wide visual field lattice projection part 42 and the three- dimensional shape of paste solder is operated by a wide visual field judging part 35 and, after the imaging and operation of four kinds of lattice patterns mutually different in phase are completed, a printing state is judged. A place judged to be not good is moved to the minute visual field imaging device 12 to operate a detailed three-dimensional shape according to a phase pattern.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection device for inspecting the state of paste solder printed on a printed circuit board,
More specifically, the present invention relates to a paste solder printing state inspection device that inspects a paste solder printing state using a pair of imaging devices having different imaging magnifications.

[0002]

2. Description of the Related Art In order to meet recent demands for miniaturization and high performance of electronic equipment, high-density mounting of electronic components on a printed circuit board has become an important issue. To answer this problem, the land on the printed circuit board is minimized and the pattern interval is narrowed, and a reflow method using paste solder is used as a surface mounting method for electronic components. The soldering failure occurs in the mounting by the above method is often caused by the defective printing state of the paste solder on the printed circuit board, so the printing state of the paste solder is inspected, but as a method therefor Conventionally, a method using a two-dimensional or three-dimensional shape inspection device and a method using visual inspection have been used.

[0003]

When the above-mentioned shape inspection device is used as a method for inspecting the printed state of paste solder, the inspection speed is slower than the production speed of the line, so the inspection device is not a production line. It is an independent device, and in the early stage of production, it inspects the printed state of all or a high percentage of printed circuit boards, but when production is in full swing, it is a sampling inspection, which is one of many printed circuit boards. Since only some of the boards have been inspected, if there is a printing failure on the uninspected PCB, the PCB will flow to the line, resulting in defective products. There was a problem. Further, in the visual method, since the print pattern is miniaturized as described above, there is a problem that the inspection becomes a harsh operation for the operator, and an inspection omission and a misunderstanding easily occur.

The present invention was devised to solve the above problems, and an object of the present invention is to provide a paste solder printing state inspection device capable of inspecting the paste solder printing state at high speed.

[0005]

In order to solve the above problems, a paste solder printing state inspection apparatus of the present invention comprises a pair of image pickup devices having different image pickup magnifications, and one of the pair of image pickup apparatuses having a lower image pickup magnification. The image pickup device as a wide-field image pickup device and the other as a fine-field image pickup device, and an arbitrary position on the printed board on which the paste solder is printed is defined as , A wide-field grid projection unit for projecting a sinusoidal intensity grid pattern onto a printed circuit board located in the field of view of the wide-field imaging device, and a position within the field of view of the fine-field imaging device. A fine-field grid projection unit that projects a sine-intensity grid pattern onto a printed circuit board and a wide-field imaging device that images the printed circuit board on which the grid pattern is projected by the wide-field grid projection unit The printing state of the paste solder based on the output of the wide-field determination unit that determines the printing state of the paste solder based on the output, and the output of the fine-field imaging device that images the printed circuit board on which the grid pattern is projected by the fine-field grid projection unit. With a configuration including a fine visual field determination unit that determines the print state, the fine visual field determination unit determines the print state for a portion of the printed circuit board that is not determined to be in good print state by the wide visual field determination unit. Let it be done.

[0006]

The printed circuit board is fixed to the circuit board moving unit, and the fixed printed circuit board is moved to the field of view of the wide-field imaging device.
In this state, the grid pattern is projected on the printed board by the wide-field grid projection unit. An image of the printed circuit board is picked up by the wide-field image pickup device, and the picked-up output is guided to the wide-field judgment unit to judge the printing state of the paste solder. As for the part of the printed circuit board that is judged that the printing condition does not meet the standard value in this judgment, the strict judgment standard is adopted because the wide-field imaging device has a wide imaging range. The fine-field imaging device performs detailed imaging of the printed circuit board in a state where it is positioned within the visual field of the apparatus and the grid pattern is projected by the micro-field grid projection unit. Then, based on the detailed image output, the fine-field determination unit determines the printing state of the paste solder.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an external perspective view showing an embodiment of the present invention.

In the figure, above the XY table 13 which constitutes the board moving portion for mounting and fixing the printed board 14 on which the paste solder is printed, there are substantially square peepholes 211 and 212 at the two positions. A flat, substantially rectangular optical plate 21 having a lens is attached to the upper side of each of the viewing holes 211 and 212, and the camera stands 111 and 121 fixed to the optical plate 21 are slid vertically. CCD cameras 11 and 12 whose positions and postures are fixed by stand carriers 112 and 122 are installed.

Regarding the pair of CCD cameras 11 and 12, the focal length of the imaging lens 113 of the CCD camera 11 is CC.
It is set to be shorter than that of the imaging lens 123 of the D camera 12, and the CCD camera 11 is a wide-field imaging device that captures a wide field of view, and the CCD camera 12 captures a minute portion in detail. It is a fine-field imaging device for.

An upper part of the optical plate 21 and a peephole 211
, 212 is a projector for projecting a lattice pattern having a sinusoidal intensity in the vicinity of the end opposite to the camera stands 111, 121, and a projector in which a liquid crystal cell is housed therein. 15 and 16 are attached, and declination mirrors 151 and 161 for irradiating the grating pattern at a predetermined angle are provided in front of the projection directions of the projectors 15 and 16.

The projector 15 is a wide-field grid projection unit for projecting a grid pattern corresponding to the wide-field imaging device 11.
15, the projector 16 includes a fine-field grid projection unit 16 for projecting a grid pattern corresponding to the fine-field imaging device 12.
Has become.

Further, glass fibers 152 and 162 for guiding light from a light source (not shown) are connected to the wide-field grating projection unit 15 and the fine-field grating projection unit 16, respectively, and are connected to the corners of the optical plate 21. The unit is equipped with a composite control unit 22 in which devices for performing various controls are stored.

Further, epi-illuminators 17 and 18 which are ring-shaped LED illuminators for performing epi-illumination are provided around the respective tip portions of the imaging lenses 113 and 123, and the peephole 211 is provided.
Below each of the 212, there are slanting illuminators 19 and 20 which are ring-shaped LED illuminating devices for performing slanting illumination.
The image pickup lenses 113 and 123 are attached so that their axial centers are apart from the central axes thereof.

The arrow A in the figure indicates the flow direction of the printed circuit board 14.

FIG. 2 is a block diagram showing the electrical construction of an embodiment of the present invention.

The output of the wide-field imaging device 11 is the switch S1 a
The output of the fine-field imaging device 12 is led to the contact, and is connected to the contact b of the switch S1. And c of switch S1
The contact is guided to the A / D converter 31, and the output of the A / D converter 31 is connected to the c contact of the switch S2. The contact a of the switch S2 is connected to the image memory 32a, and the contact b of the switch S2 is connected to the image memory 32b.

The output of the image memory 32a is sent to the contact a of the switch S3, the output of the image memory 32b is sent to the contact b, and the contact of the switch S3 is connected to the D / A converter 3.
3, the wide-field determination unit 35 and the fine-field determination unit 36 are introduced into three blocks.

The output of the wide visual field determination unit 35 is sent to the fine visual field determination unit 36 and the main control unit 37, and the output of the fine visual field determination unit 36 is guided to the main control unit 37. The output of the D / A converter 33 is given to the monitor 34.

The output of the main controller 37 is the table controller 38,
It is introduced into the drive circuit 39, the drive circuit 40, the liquid crystal cell control unit 41, and the shutter control unit 44. The output of the table control unit 38 is given to the substrate moving unit 13 as an output for controlling the movement of the substrate moving unit 13, and the output of the drive circuit 39 is output to the epi-illuminators 17 and 18 as an illuminance control output to the drive circuit. The output of 40 is sent to the oblique illuminators 19 and 20 as a similar control output.

The output of the liquid crystal cell control unit 41 is introduced into both the wide-field grid projection unit 15 and the fine-field grid projection unit 16 as a signal for controlling a sine intensity grid pattern.
The output of the shutter control unit 44 is the glass fiber 152.
, 162 to a shutter (not shown) inserted in the middle.

In the above configuration, the three switches S1
The connections of S3 to S3 are controlled by the output (not shown) from the main control unit 37.

FIG. 3 is a flow chart showing the main operation of one embodiment of the present invention. The operation of one embodiment of the present invention will be described below with reference to FIG.

First, from a host computer (not shown), a CA of a screen mask used for screen printing is displayed.
The D data is sent to the main controller 37. This CAD data is converted by the main controller 37 into data for use in inspection. Further, the main control unit 37, from these data,
A reference value used to determine the printing state of the printed circuit board 14 is calculated.

When the above-mentioned initial operation is completed, the printed circuit board 14 is attached to the circuit board moving unit 13, and the printed circuit board 14 is attached.
The substrate moving unit 13 is moved so that the upper reference position is located at the reference position within the field of view of the microscopic field imaging device 12.

In this state (for switch S1, the c contact is connected to the b contact, and for switches S2 and S3, the c contact is connected to the a contact), the fine-field image pickup device 12 performs image pickup (epi-illumination). Turn on the device 18),
The output is stored in the image memory 32a. Then, based on the stored data, the fine-field determining unit 36 calculates the reference position of the printed circuit board 14, and calculates the difference between the preset reference position and the reference position of the attached printed circuit board 14. Then, the calculation result is used as a correction value for correcting the clamping error at the time of mechanical clamping and the inherent error of each printed circuit board 14, and the value is used as the main control unit 37.
To (step S11).

Then, the main control section 37 refers to the correction value by way of the table control section 38, and refers to the above-mentioned correction value, and the first image pickup area of the image pickup areas divided into a plurality of portions is wide-field image pickup apparatus. Position within 11 fields of view. Then, the wide-field grid projection unit 15 controls the projection of a grid pattern having a predetermined sine intensity, thereby providing a wide-field imaging device.
11 to perform imaging (for switches S1 to S3,
Each c contact is connected to the a contact, and the incident light illuminator 17 and the oblique illuminator 19 illuminate the printed circuit board 14 if necessary).

The image data imaged by the wide-field imaging device 11 by the above method is guided to the image memory 32a and stored therein.

The image data stored in the image memory 32a is guided to the wide-field determining unit 35, and the three-dimensional shape of the paste solder is first calculated by the phase shift method. In parallel with the operation of the wide-field determination unit 35, the main control unit 37 sends a control output to the liquid crystal cell control unit 41 to project a grid pattern having different phases from the wide-field grid projection unit 15, and in this state. In the same area, the wide-field imaging device 11 re-images the area, and the imaging output is stored in the image memory 32b.
(Connect the c contact of switch S2 to the b contact).

The wide-field determination unit 35 starts the calculation based on the image data stored in the image memory 32b immediately after finishing the first calculation by the phase shift method based on the image data stored in the image memory 32a ( Connect the c contact of switch S3 to the b contact).

Further, in parallel with the above operation, the grid patterns having different phases are projected again by the wide-field grid projection unit 15,
Image memory 32 for imaging by the wide-field imaging device 11 and its output
Remember to a.

When the imaging based on the four types of lattice patterns having mutually different phases is completed and the calculation based on the imaging output is completed, the three-dimensional shape is calculated. Therefore, the paste solder paste is calculated based on the calculated shape. The print status is determined.

With respect to the next area to be imaged, the printing state of the paste solder is determined by repeating the same operation as described above. By repeating the same operation below, the three-dimensional shape of all the imaged areas is calculated.
(Steps S12, S13).

The determination based on the above calculation is performed by the wide-field imaging device 11
Since the setting is made to reduce the number of times the printed circuit board 14 is imaged by widening the field of view, it is determined that only the printing state close to the ideal shape is good. As a result, the printed shape may not be determined to be good even if the printed shape has no practical problems. Therefore, even if a portion is determined to be unsatisfactory, there is an extremely large possibility that it will be determined to be good in detailed inspection.

In the operations of steps S12 and S13, when it is determined that all the points are good, the main control section 37 is informed of that fact.
Moves the substrate moving unit 13 to the initial position through the table control unit 38, performs an operation for replacing the printed circuit board 14, and ends the inspection of the printed circuit board 14 (step
S14).

If there is a portion determined to be not good, that portion is moved to the visual field of the fine visual field imaging device 12, and the fine field grid projection unit 16 projects the lattice pattern, and then the phase shift method is performed. According to, a detailed three-dimensional shape calculation is performed.

Regarding the operation for this calculation, the image memories 32a and 32b are made to alternately store the image outputs in the same manner as described above, and the third order based on the stored data is stored in the order in which the storage is completed. The calculation of the original shape is performed by the fine visual field determination unit 36. When the detailed calculation result of the three-dimensional shape satisfies the reference value, the determination output indicating that the product is non-defective is sent out, and in other cases, the determination output indicating that the printing is defective is sent to the main control unit 37. Send (Steps S15, S1
6).

The main controller 37 sends an output designating the subsequent flow of the printed circuit board 14 to an external device in accordance with the output of the fine visual field determination unit 36. Further, when it is necessary to monitor the print failure and the location, the outputs of the image memories 32a and 32b are led to the monitor 34 via the D / A converter 33 and displayed there.

As described above, in the present embodiment, the configuration is such that two sets of image memories 32a and 32b are provided, so that the next image is picked up in parallel with the image data calculation operation. Therefore, it is possible to further increase the inspection speed. It should be noted that the present invention is not limited to the above-described embodiment, and when the purpose of the operation is the same, any configuration (wide-field imaging device 11, fine-field imaging device 12) can be used.
Can be attached to the image memories 32a and 32b, etc.).

[0040]

The paste solder printing state inspection apparatus according to the present invention includes a pair of image pickup devices of a wide-field image pickup device and a fine-field image pickup device having different image pickup magnifications, and a wide-field image pickup device and a fine-field image pickup device, respectively. Correspondingly, a grid projection unit that projects a grid pattern of sine intensity and a determination unit are provided on the printed board, and determination is first performed in a wide field of view. Then, in this determination, only the portion of the printed circuit board that is determined that the printing state does not satisfy the reference value is configured to perform the determination based on the detailed imaging with the fine field of view, so only the portion that requires detailed data for the determination, Since the image is captured in detail only, there is an effect that it is possible to perform high-speed processing for inspecting the printed state of the paste solder.

[Brief description of drawings]

FIG. 1 is an external perspective view showing an embodiment of the present invention.

FIG. 2 is a block diagram showing an electrical configuration of an embodiment of the present invention.

FIG. 3 is a flowchart showing a main operation of one embodiment of the present invention.

[Explanation of symbols]

 11 Wide-field imaging device 12 Micro-field imaging device 13 Substrate moving section 15 Wide-field grid projection section 16 Micro-field grid projection section 35 Wide-field judgment section 36 Micro-field judgment section

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshii Shigeyama 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Within Sharp Corporation (72) Inoue Hideyuki 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Within Yap Co., Ltd.

Claims (1)

[Claims] 1. A pair of image pickup devices having different image pickup magnifications, and when the image pickup device having a lower image pickup magnification of the pair of image pickup devices is a wide-field image pickup device and the other is a fine-field image pickup device, a paste A board moving unit that moves an arbitrary position on the printed board on which solder is printed to an arbitrary position in the field of view of the wide-field imaging device and an arbitrary position in the field of view of the fine-field imaging device, and the field of view of the wide-field imaging device. A wide-field grating projection unit for projecting a sine-intensity grid pattern onto the printed circuit board located inside, and a fine-field grid projection unit for projecting a sine-intensity grid pattern onto the printed circuit board located within the field of view of the micro-field imaging device. And a wide-view that determines the printing state of the paste solder based on the output of a wide-field imaging device that images the printed circuit board on which the grid pattern is projected by the wide-field grid projection unit. A determining unit, and a fine-field determining unit that determines the printing state of the paste solder based on the output of the fine-field imaging device that images the printed circuit board on which the grid pattern is projected by the fine-field grid projecting unit, Regarding the portion of the printed circuit board that is not determined to be in good print condition by the wide-field determination unit,
A paste solder printing state inspection device, characterized in that the printing state is determined by the fine field determination unit.