JPH0618239A - Cream solder print inspection equipment - Google Patents

Abstract

PURPOSE:To obtain a cream solder print inspection equipment in which the area of cream solder is checked correctly with no influence of directivity of illumination and printing state of cream solder can be inspected correctly. CONSTITUTION:The cream solder print inspection equipment comprises a line sensor 3 disposed above a board 1 printed with a cream solder, and a pair of illuminating means 23, 23 arranged in parallel in the longitudinal direction on the opposite sides of the line sensor 3, wherein the printed board 1 is image pickuped by means of the line sensor 3 while being illuminated through the illuminating means 23, 23. A window frame is then set at a part to be inspected for an image thus produced and the image in the window frame is analyzed thus inspecting the printed state of cream solder 2. The inspection equipment further comprises means 7 for extracting features within the window frame, and solder area decision means 8 for determing an area correction value based on the illuminating direction of the illuminating means 23, 23 and checking good or not basing on the area of cream solder pattern.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for inspecting a printed state of a printed circuit board printed with cream solder, and more particularly to an apparatus for inspecting the quality of a solder area.

[0002]

2. Description of the Related Art A printed circuit board on which cream solder is printed is imaged by a line sensor, a window frame portion of a portion to be inspected is set for an image based on the video signal, and an image in the window frame portion is analyzed to perform solder paste. The conventional cream solder printing inspection device for inspecting the printing state of is configured as shown in FIG.

That is, a line sensor 14 is arranged above the printed circuit board 1 on which the cream solder 2 is printed, and a pair of illuminating means 23, 23 are arranged on both sides of the line sensor 14 in parallel with the longitudinal direction thereof. These lighting means 2
The printed circuit board 1 is imaged by the line sensor 14 while being illuminated by 3, 23. The video signal transmitted from the line sensor 14 is received by the image storage means 16 and stored therein. Next, of the video signals stored in the image storage means 16 by the binarization means 17,
The image in the window frame portion for cream solder inspection is taken out and binarized, the control unit 18 obtains the area and the center of gravity of the binary image received from the binarizing means 17, and compares it with a preset judgment reference area. Then, it was determined whether the area of the cream solder was good or bad, and thus the print state was good or bad.

[0004]

However, according to the conventional cream solder printing inspection apparatus, as shown in FIG. 4, due to the directivity of the illumination of the illumination means 23, 23, the reflected light of the inclined portion of the cream solder 2 is lined. As shown in FIG.
And as indicated by hatching in FIG.
There is an area P where the light does not return at 4 (3).

In the case shown in FIG. 2, that is, the cream solder 2, the line sensor 14 (3) and the illumination means 23, 23.
When the longitudinal directions of any of the above are parallel, the reflected light of the inclined portions 19 located on both long sides of the cream solder 2 does not enter the line sensor 14 (3), and the solder area detected by that amount is Get smaller.

In the case shown in FIG. 3, that is, the cream solder 2
Longitudinal direction, line sensor 14 (3) and lighting means 2
When the longitudinal directions of 3 and 23 have a right angle relationship, the reflected light of the inclined portions 20 located on both short sides of the cream solder 13 does not enter the line sensor 14 (3) and is detected accordingly. Solder area becomes smaller.

As is clear from comparison between FIG. 2 and FIG.
Since the decrease rate of the detected solder area is different between the two, if the judgment reference area is set based on either case, there will be an error in the judgment of the quality of the cream solder area in the other case. There is.

[0008]

In order to solve the above problems, the present invention arranges a line sensor above a printed circuit board on which cream solder printing is performed, and a pair of line sensors are arranged on both sides of the line sensor in parallel with the longitudinal direction. The above-mentioned printed circuit board is imaged by the line sensor in a state of being illuminated by these illuminating means, the window frame portion of the portion to be inspected is set for the image by the video signal, and the image in the window frame portion is set. In the cream solder printing inspection apparatus for inspecting the printed state of cream solder by analyzing the above, a feature extraction means for obtaining the area of the cream solder pattern from the image in the window frame portion,
The area correction value is obtained based on the illumination direction of the illumination means and the direction in which the cream solder to be inspected is arranged, the area correction value thus obtained, and the area of the cream solder pattern obtained by the feature extraction means. , And a solder area determining means for determining whether the area of the cream solder is good or bad based on three preset determination reference areas.

[0009]

According to the present invention, the area correction value is obtained based on the illumination direction of the illumination means and the direction in which the cream solder to be inspected is arranged, and the area correction value and the area of the cream solder pattern by actual measurement are determined. Since the quality of the area of the cream solder is judged based on three factors, the reference area and the area of the cream solder, considering the difference in the reduction rate of the detected area caused by the direction of the illumination and the arrangement direction of the cream solder, The quality can be accurately determined.

[0010]

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

In FIG. 1, 1 is a printed circuit board, 2 is cream solder printed on the printed circuit board 1, and 3 is a color line sensor. Reference numerals 23 and 23 denote a pair of illumination means arranged on both sides of the color line sensor 3 arranged above the printed circuit board 1 and in parallel with the longitudinal direction thereof. Each illuminating unit 23 irradiates light obliquely downward to illuminate the image pickup surface on the printed circuit board 1.

[0012] Reference numeral 5 receives a color image signal picked up by the line sensor 3, and in this color image signal, a portion exhibiting a color within the color distribution of the solder color given in advance from the control section 9 is soldered. It is a color extraction unit that determines a portion and transmits color extraction data indicating the portion.

Reference numeral 6 is a smoothing means for receiving the color extraction data and smoothing noise components.

A feature of 7 is that the window frame portion of the portion to be inspected is set, the smoothed signal in the window frame portion is taken out from the smoothing means 6, and the area and the center of gravity of the cream solder pattern to be inspected are obtained. It is an extraction means.

Reference numeral 8 is a solder area determining means, which has the following functions. That is, the area correction value is obtained based on the illumination direction of the illumination means 23, 23 and the direction in which the cream solder 2 to be inspected is arranged, and the area correction value thus obtained is obtained by the feature extraction means. The quality of the area of the cream solder is determined based on the area of the cream solder pattern and the preset judgment reference area.

Specifically, the area correction value and the judgment reference area are stored in advance in the control section 9 corresponding to each inspection object, and the solder area judging means 8 based on these is the area of the cream solder. The quality of is judged. Then, as shown in FIG. 2, the longitudinal direction of the cream solder 2 and the illumination means 23, 23.
In the case where the longitudinal directions of are parallel to each other, when the area S of the detected cream solder is in the following range, it is determined as “good”.

Min-A.ltoreq.S.ltoreq.Max-A Max ... Maximum value of judgment reference area Min ... Minimum value of judgment reference area A ... Area corresponding to inclined portion 19 Similarly, FIG. As described above, when the longitudinal direction of the cream solder 2 and the longitudinal directions of the illuminating means 23, 23 are in a right angle relationship, when the detected area S of the cream solder is in the following range, it is determined as “good”. .

Min-B≤S≤Max-B Max ... Maximum value of judgment reference area Min ... Minimum value of judgment reference area B ... Area corresponding to slope 20 Values of A and B above The difference in the reduction ratio of the detection area caused by the illumination direction and the arrangement direction of the cream solder can be corrected and the quality of the area of the cream solder can be accurately determined.

[0019]

According to the present invention, the cream solder printing inspection capable of accurately determining the quality of the area of the cream solder and accurately inspecting the printing state of the cream solder without being influenced by the directivity of the illumination. A device can be provided.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an exemplary embodiment of the present invention.

FIG. 2 is a principle diagram showing a relationship between an illumination direction and a reflection state of cream solder.

FIG. 3 is a principle diagram showing a relationship between an illumination direction and a reflection state of cream solder.

FIG. 4 is a schematic side view showing a relationship between an illumination direction and a reflection state of cream solder.

FIG. 5 is a block diagram showing a conventional example.

[Explanation of symbols]

 1 Printed Circuit Board 2 Cream Solder 3 Line Sensor 5 Color Extracting Means 6 Smoothing Means 7 Feature Extracting Means 8 Solder Area Determining Means 23 Illuminating Means

Claims (2)

[Claims] 1. A line sensor is arranged above a printed circuit board printed with cream solder, and a pair of illuminating means is arranged on both sides of the line sensor in parallel to the longitudinal direction of the line sensor.
The printed circuit board is imaged by the line sensor in a state where it is illuminated by these illumination means, the window frame portion of the portion to be inspected is set for the image based on the video signal, and the image in the window frame portion is analyzed to measure the cream solder. In a cream solder printing inspection device for inspecting a printing state, a feature extraction means for obtaining the area of the cream solder pattern from the image in the window frame portion, an illumination direction of the illumination means, and a direction in which the cream solder to be inspected is arranged are arranged. A base area correction value is obtained, and the area correction value thus obtained, the area of the cream solder pattern obtained by the feature extracting means, and the preset judgment reference area A solder paste printing inspection device, comprising: a solder area determination means for determining quality. 2. The line sensor is a color line sensor, receives a color image signal picked up by the line sensor, and in the color image signal, colors within a color distribution of a solder color given in advance. And a smoothing process for determining the soldered part and transmitting color-extracted data indicating the part, and receiving the color-extracted data to perform smoothing processing and transmitting a smoothed signal. The cream solder printing inspection device according to claim 1, further comprising: