JP2000205837A - Inspection device and method for printing machine of cream solder and printing machine with its inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately inspect cream solder printed at a low cost in an inspec tion device picking up a printed circuit board printed with cream solder. SOLUTION: A printed circuit board 1 being an inspected subject is picked up with a monochrome camera 6. Thereat, a green color on the board 1 is removed by passing an incident light through a filter 7 to reduce the brightness level. Thereby, a difference in the brightness level between a wiring pattern 5 and a cream solder 2 on the board 1 is produced. The cream solder 2 is processed by a thresholding part 9 after passing the light through the filter 7 and measurement for an area and position based on binary information is performed by an arithmetic and logistical part 10 and a pass/fail judgement is executed by a judgement part 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection apparatus and method for inspecting the shape of cream solder printed by a printing machine for printing cream solder on a printed circuit board on which electronic components are mounted, and a printing apparatus having the inspection apparatus. It is about the machine.

[0002]

2. Description of the Related Art In recent years, in the mounting method of electronic parts,
With the advent of new devices such as CSP (Chip Size Package), inspection after cream solder printing has become increasingly important. Under these circumstances, high performance inspection of the printed state of the cream solder has come to play an important role in determining the quality of the final product. Hereinafter, an example of the above-described conventional inspection apparatus will be described with reference to the drawings. FIG. 5 is a diagram showing a configuration of a conventional apparatus for inspecting cream solder printed on a printed circuit board. The black and white camera 34 images the printed circuit board 32 on which the cream solder 31 is printed, sets a window frame portion of the inspected portion with respect to the image based on the video signal, analyzes the image in the window frame portion, and
Inspect the print status of.

That is, a black-and-white camera 34 is arranged above a printed board 32 on which the cream solder 31 is printed, and illuminations 35 are arranged on both sides thereof. The video signal transmitted from the black-and-white camera 34 is binarized by a binarization processing unit 36 in comparison with binarization data of the cream solder 31 which is set in advance. Next, the calculation unit 37 obtains the area and the center of gravity of the cream solder 31 based on the binarized information of the cream solder 31, and determines a predetermined judgment reference area and judgment reference position shift amount with the judgment unit. 38, the quality of the cream solder printing state was determined. Note that 3 in FIG.
Reference numeral 3 denotes a land of the printed board 32, and reference numeral 39 denotes a wiring pattern of the printed board 32.

[0004]

However, in a conventional apparatus for inspecting cream solder after printing by a black-and-white camera, the brightness level of the cream solder may be the same as the brightness level of the background. Therefore, the cream solder alone cannot be binarized, and the cream solder cannot be normally inspected in many cases. In the case of a color image processing method or a method based on three-dimensional measurement, the apparatus itself is expensive and it is difficult to mount the equipment.

Further, in the conventional optical system, it is difficult to measure an area accurately due to irregular reflection of irradiation light due to a flux or the like on the cream solder surface, and variation in reflected light due to the shape of the printed cream solder.

Further, in the conventional optical system, it is necessary to use illumination close to the incident light to identify a characteristic pattern on a printed circuit board for positioning, and diffuse illumination from all directions is required to identify cream solder. It has been difficult to achieve both discriminations with one optical system. The present invention solves the above-described problem, and in an inspection apparatus for imaging a printed circuit board on which cream solder is printed, an inspection apparatus for a cream solder printing machine that can accurately and inexpensively inspect the printed cream solder. An object of the present invention is to provide a printing press having the inspection apparatus and the inspection method.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is configured as follows.

According to a first aspect of the present invention, there is provided an inspection apparatus for inspecting a cream solder printed by a printing machine for printing a paste-like cream solder with an imaging device, wherein the green color is selected from the wavelengths incident on the imaging device. An inspection apparatus for a cream solder printing machine, comprising: a green wavelength removing member that removes only a wavelength.

According to a second aspect of the present invention, there is provided the inspection apparatus for a cream solder printing machine according to the first aspect, comprising an illuminating device for illuminating a side surface of the cream solder from a direction different from a height direction of the solder. I do.

According to a third aspect of the present invention, the cream solder printing according to the first aspect, further comprising an illuminating device for illuminating all sides of the cream solder omnidirectionally from a direction different from the height direction of the solder. Provide machine inspection equipment.

According to a fourth aspect of the present invention, there is provided the inspection apparatus for a cream solder printing machine according to any one of the first to third aspects, further comprising an incident light source for illuminating the positioning pattern on the substrate. .

According to a fifth aspect of the present invention, the illumination device according to the second or third aspect, an incident light source for illuminating the positioning pattern on the substrate, and illuminating the illumination device and the incident light source 2. A printing device for a cream solder printing machine according to claim 1, further comprising a control device for switching according to a control object.

According to a sixth aspect of the present invention, there is provided a cream solder printing machine having the above-described printing apparatus according to any one of the first to fifth aspects.

According to a seventh aspect of the present invention, there is provided an inspection method for inspecting cream solder printed by a printing machine for printing paste-like cream solder by an image pickup device, wherein green light among wavelengths incident on the image pickup device is used. Provided is an inspection method for a cream solder printing machine, characterized in that only a wavelength is removed.

According to an eighth aspect of the present invention, when the cream solder is imaged by the imaging device, the cream solder according to the seventh aspect is illuminated from a direction different from a height direction of the solder in a side surface of the cream solder. An inspection method for a solder printing machine is provided.

According to a ninth aspect of the present invention, when the cream solder is imaged by the imaging device, all side surfaces of the cream solder are omnidirectionally illuminated from a direction different from the height direction of the solder. According to a seventh aspect, there is provided an inspection method for a cream solder printing machine.

According to a tenth aspect of the present invention, the positioning pattern on the substrate is illuminated with an epi-illumination light source.
The present invention provides an inspection method for a cream solder printer according to any one of the above aspects.

According to the eleventh aspect of the present invention, the eighth or ninth aspect
The cream solder printing machine according to a seventh aspect, wherein control is performed to switch between illuminating as described in the aspect and illuminating the positioning pattern on the substrate with an epi-illumination light source in accordance with an object to be illuminated. Provide a printing method.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Various embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration of a cream solder inspection apparatus according to a first embodiment of the present invention. In FIG. 1, 1 is a printed circuit board, 2
Denotes a cream solder printed on the printed circuit board 1, 4 denotes a land on the printed circuit board 1, and 5 denotes a wiring pattern on the printed circuit board 1. Reference numeral 6 denotes a black-and-white camera, 7 denotes a filter for removing a green component, 8 denotes a lighting device, and 9 denotes a black-and-white camera.
Receiving a video signal imaged in step 2, extracting a portion indicating the brightness of the cream solder 2 set in advance, and binarizing it.
It is a value processing unit. Reference numeral 10 denotes an operation unit that measures the area and size of the solder extracted by the binarization processing unit 9 by operation, and 11 denotes a determination unit that determines the quality of solder printing based on a preset threshold value. .

FIG. 2 shows that a portion of the substrate on which the solder is not printed (including a portion of the wiring pattern other than the portion on which the solder is printed) is green due to the resist applied to the substrate, Since the brightness of green and the brightness of solder are substantially the same, the operation of the filter 7 for removing the green color will be described. In FIG. 2A, the vertical axis indicates the transmittance,
FIG. 6 is a characteristic diagram of the filter 7 in which a horizontal axis indicates a wavelength. FIG.
FIG. 3B is a diagram illustrating the effect of the filter 7. That is, it can be seen that when the light passes through the filter 7, blue or red light is transmitted by 80% or more, but only green is not transmitted. FIG.
In (b), a portion surrounded by a dotted line is a region indicating the brightness of the solder.

FIG. 3 is a diagram showing the configuration of the lighting device 8. 12 is an illuminating device for irradiating the cream solder 2 from all directions around it, 13 is an epi-illumination device for identifying a characteristic pattern on the printed circuit board 1, 14 is a control unit for switching the illuminating device 12, Reference numeral 15 denotes a data storage unit having data for specifying a target to be imaged. With this configuration, the control unit 14 illuminates only the omnidirectional lighting device 12 to perform omnidirectional illumination according to the target object, specifically, when illuminating the solder, while performing planar illumination other than solder. To illuminate the pattern, the omnidirectional illumination device 12 is turned off and the epi-illumination device 13 is turned on by the control unit 14, and the epi-illumination device 13 can illuminate the planar pattern.

FIG. 4 explains the relationship between the shape of the cream solder and the area measurement, as will be described later.

Hereinafter, the operation of the cream solder inspection apparatus of each of the above components will be described with reference to FIGS. The printed board 1 as an example of the inspection object is imaged by the black-and-white camera 6. At this time, when the incident light passes through the filter 7, as shown in FIG. 2B, the green color indicating the portion of the printed circuit board 1 where the solder is not printed is removed, and the brightness level is reduced. This causes a difference in the brightness level between the wiring pattern 5 on the substrate 1 and the cream solder 2. After passing through the filter 7k, the cream solder 2 is binarized by the binarization processing unit 9,
The arithmetic unit 9 measures the area and position of the solder 2 based on the quantified information, and the determination unit 10 determines whether the area and position of the solder 2 are within an allowable range.
The quality of solder printing is determined.

Next, when an image of the cream solder 2 is taken, an illumination device 8 for irradiating the entire cream solder 2 is used, so that an ideal shape (for example, as shown in FIGS. 4 (a) and 4 (b), even if the cream solder 2 is not the shape as shown in FIG.
As in the case of the cream solder 2 having an ideal shape as shown in FIG. 4D, an accurate two-dimensional image can be obtained as shown in FIGS. That is, in this embodiment, when the solder 2 is illuminated by the incident light source from above the solder 2 downward, the light reflected on the surface of the solder 2 enters the monochrome camera 6 above the solder 2, and Imaging is performed. Therefore, as shown in FIG. 4B, when the side surface of the solder 2 is hardly inclined and when the light is illuminated downward from above the solder 2 by the incident light source, most of the reflected light from the solder 2 enters the camera. Ideal shape solder 2
Then, as shown in FIG. 4 (e), the part that cannot be measured in the solder 2 is a very small area around the solder 2,
Most of the solder 2 can be measured.

On the other hand, as shown in FIG.
When the side surface of the solder 2 has a gentle inclination, the reflected light from the incident light source reflected on the side surface of the
Do not enter. For this reason, as shown in FIG. 4D, the side surface portion other than the plane of the central portion of the solder 2 becomes an unmeasurable region, and the accurate area and position of the solder 2 cannot be measured. On the other hand, in the present embodiment, FIG.
(C) As shown in FIG.
4 can be illuminated from the side surface of the solder 2, the reflected light beam reflected on the side surface of the solder 2 can enter the black-and-white camera 6, and as shown in FIG. Most of the area on the side of the second can be measured.

Here, a control configuration of the lighting device 8 will be described.
This will be described with reference to FIG. The data held in the data storage unit 15 is analyzed by the control unit 14 for driving the illumination device, and the object to be imaged is a characteristic pattern on the printed circuit board 1 (for example, a positioning pattern used for positioning such as a mark). In this case, the epi-illumination device 13 which is a component of the illumination device 8 is turned on, and the omnidirectional illumination device 12 is turned off.
Further, the object of imaging is the cream solder 2 on the printed circuit board 1.
In this case, the omnidirectional lighting device 12 is turned on and the epi-illumination lighting device 13 is turned off. As a result, the amount of light falling perpendicular to the plane can be reduced. As a result, a better contrast can be obtained in the case of identifying the characteristic pattern, and an area measurement error due to the reflection of the flux can be reduced in the case of the solder inspection.

According to the above embodiment, the following operation and effect can be obtained. First, when illuminating and imaging the cream solder 2 printed on the printed circuit board 1, a difference in the brightness level between the solder 2 and the green portion on the printed circuit board 1 occurs, which has been difficult with conventional monochrome image processing. Was. However, in the present embodiment, the difference in brightness between the cream solder 2 on the printed circuit board and the pattern on the printed circuit board 1 that is green is increased by removing the green wavelength with the filter 7. Can be accurately distinguished, whereby the inspection of the cream solder 2 can be performed accurately.

Further, even when the shape of the cream solder 2 is not correct, the inspection can be performed accurately. Further, it is possible to identify the feature pattern on the printed circuit board 1 and inspect the cream solder at the same time with the same optical system.

[0029]

As described above, by cutting out the green component among the components of the light beam incident on the image pickup apparatus, the cream solder on the conventional printed circuit board and the pattern on the printed circuit board having a green color can be accurately determined. The problem that could not be distinguished can be solved, so that the cream solder can be inspected accurately.

Furthermore, by irradiating the printed cream solder with light from all directions without illuminating the solder with a unidirectional light source, the reflection of the flux contained in the cream solder and the shape of the cream solder are affected. Accurate inspection can be performed without being performed. Further, by combining the omnidirectional illumination and the epi-illumination, the identification of the characteristic pattern on the printed circuit board and the inspection of the cream solder can be made compatible by selecting and inspecting the optimal illumination. Furthermore, by switching between the epi-illumination and the omnidirectional illumination for the cream solder from all directions according to the object to be imaged, more accurate identification of the characteristic pattern and inspection of the cream solder can be performed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a cream solder print inspection apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an operation of a filter that removes green color only in FIG. 1;

FIG. 3 is a diagram showing a configuration of the lighting device of FIG. 1;

FIG. 4 is a diagram showing the relationship between the shape of cream solder and area measurement.

FIG. 5 is a diagram showing a configuration of a conventional cream solder print inspection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printed board 2 Cream solder 4 Land 5 Wiring pattern 6 Black-and-white camera 7 Filter 8 Illumination device 9 Binarization processing unit 10 Operation unit 11 Judgment unit 12 Omnidirectional illumination device 13 Epi-illumination device 14 Control unit 15 Data storage unit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F065 AA03 AA21 AA49 AA58 BB02 BB05 CC01 CC26 DD09 FF42 GG17 HH12 HH13 HH14 JJ03 JJ09 LL26 NN01 QQ04 QQ21 QQ25 RR05 RR08 5E319 BB05 CD29 CD53

Claims (11)

[Claims] 1. An image pickup device (6) for printing cream solder (2) printed by a printing machine for printing cream solder paste.
An inspection apparatus for a cream solder printing machine, comprising: a green wavelength removing member (7) for removing only a green wavelength among wavelengths incident on the imaging device. 2. The inspection device for a cream solder printing machine according to claim 1, further comprising an illumination device for illuminating a side surface of the cream solder from a direction different from a height direction of the solder. 3. The inspection apparatus for a cream solder printing machine according to claim 1, further comprising an illuminating device illuminating all sides of the cream solder in all directions from a direction different from a height direction of the solder. 4. The inspection apparatus for a cream solder printing machine according to claim 1, further comprising an epi-illumination light source (13) for illuminating the positioning pattern on the substrate. 5. Illumination device (8) according to claim 2 or 3.
2. An epi-illumination light source (13) for illuminating a positioning pattern on the substrate, and a control device (14) for switching the illuminating device and the epi-illumination light source according to an object to be illuminated. Printing equipment for cream solder printing machines. 6. A cream solder printing machine having the printing device according to claim 1. 7. An image pickup device (6) for printing cream solder (2) printed by a printing machine for printing paste cream solder.
An inspection method for a cream solder printing machine, wherein only a green wavelength among wavelengths incident on the imaging device is removed. 8. The inspection method for a cream solder printing machine according to claim 7, wherein when the cream solder is imaged by the imaging device, a side surface of the cream solder is illuminated from a direction different from a height direction of the solder. 9. When the cream solder is imaged by the imaging device, all side surfaces of the cream solder are omnidirectionally illuminated from a direction different from a height direction of the solder.
Inspection method for a cream solder printing machine according to the above. 10. The inspection method for a cream solder printing machine according to claim 7, wherein the positioning pattern on the substrate is illuminated by an incident light source (13). 11. Control so as to switch between illuminating as described in claim 8 or 9 and illuminating the positioning pattern on the substrate with an epi-illumination light source according to an object to be illuminated. The printing method for a cream solder printing machine according to claim 7.