JPH02216005A - Method for inspecting soldering of mounting part - Google Patents

Abstract

PURPOSE:To inspect a soldering state from the difference between the waveform shapes of height data by providing a part electrode part, a soldering part and a light detection area sensor to extract the image of an electrode terminal part and that of the soldering part. CONSTITUTION:The light source 4 arranged just above a printed circuit board 3 emits slit light 5 to said board 3 downwardly. The emitted slit light 5 is reflected from the surfaces of all of a part electrode part 1, a soldering part 2 and the board 3 to become diffused light 7 and said light 7 is detected as an image by the light detection area sensor or camera 6 arranged at a diagonally upward part with respect to the board 3. At this time, when there is no solder in the vicinity of an electrode terminal part with respect to the images of the electrode part 1 and soldering part 2, the height of the soldering part 2 shows a low value and, when solder is applied and a fillet is formed, the height of the soldering part 2 is shown as the height of the shape of the fillet. Therefore, the images of the electrode terminal part and soldering part 2 are extracted and a soldering state can be inspected from the difference between the waveform shapes of height data.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a method for inspecting the soldering state of electronic components mounted on the surface of a printed circuit board.

[Conventional technology]

Conventionally, manual visual inspection has been mainly used as a method for inspecting the soldering state of electronic components mounted on printed circuit boards. As a system for automating the appearance inspection of this type of mounted components, there is a device that optically inspects the position of the mounted components, but it has the drawback that it cannot inspect the soldered state such as unsoldered. Furthermore, there is also a method of indirect inspection using an electrical continuity test.

[Problem to be solved by the invention]

The electrical continuity test is a test to check the continuity of the soldered parts. Even if the soldering is not secure, if there is electrical continuity due to contact between the printed circuit board pattern and the electrode part of the electronic component, the test can be carried out. I passed the exam. Therefore, soldering inspection currently relies on visual inspection and has not yet been automated in a manner consistent with visual inspection, and automation is desired.

[Means to solve the problem]

In order to solve this problem, a light source or a laser light source is placed at the top to irradiate the electrodes and soldered parts of electronic components with a slit beam from above, and a light-receiving area is created to receive the diffused light from the irradiated area. By placing a sensor (CCD, photodiode, etc.) on the top, optical measurement is performed using a triangulation method, and the image obtained by the light receiving area sensor shows the height of the electronic component electrodes and solder parts from the printed circuit board. information, that is, shape information.

[Made for]

This method uses a triangulation method to focus on the fact that the image of the light-receiving area sensor, which captures the diffused light due to diffuse reflection on the irradiated surface, represents the height information of the irradiated surface from the printed circuit board. Regarding the image of the part and solder part, if there is no solder near the end of the electrode, the height of the solder part will be low; if there is solder and a fillet is formed, the height of the solder part will be low. Since the height of the fillet shape is shown, images of the electrode end and solder parts are extracted, and the soldering state is inspected from the difference in the waveform shape of the height information.

【Example】

FIG. 1 is a diagram illustrating the inspection method according to the present invention, 1
is an electrode part of an electronic component soldered on a printed circuit board 3, 2 is a solder part, 3 is a printed circuit board, and a slit light 5 is directed downward by a light source 4 such as a semiconductor laser placed vertically above the printed circuit board 3. irradiate. The irradiated slit light 5 is scattered on the surfaces of the component electrode section 1, the solder section 2, and the printed circuit board section 3 to become diffused light 7, which is disposed diagonally above (consisting of a charge-coupled device, an image sensor, etc.)
It is detected as an image by the light receiving area sensor 6 or by the camera 6. FIG. 2 is a block diagram for inspecting the soldering state of other components such as chip components, and the same reference numerals as in FIG. 1 indicate the same components. Although FIG. 3 is a different configuration diagram from FIGS. 1' and 2, it is possible to detect the image of the diffused light 7 in the same way as in FIGS. 1 and 2. FIG. 4 shows yet another configuration example, in which the component electrode portion 1 and the solder portion 2 are repeatedly scanned and irradiated with a laser beam etc. emitted from a light source 4 via a polygon mirror 9. This is an example. The difference from FIG. 1 is that by converting the irradiated light beam into a spot light, a more focused light beam can be irradiated. FIG. 5 shows an image obtained by the camera or light-receiving area sensor 6 having the configuration shown in FIGS. 1-4. Mizutani, in which the printed circuit board part 3 and the component electrode part 1 are normally soldered, has a part as shown in FIG. , an image 12 of the printed circuit board are obtained. For these, the printed circuit board section 3
If there is less solder between the solder part 1 and the component electrode part 1, the image of the solder part 11 is closer to the image 12 of the printed circuit board part 1, as shown in FIG. 5 (I+). . Furthermore, if the component electrode part 1 is not wetted with solder, as shown in Fig. 5 (
As shown in c), the image 11 of the solder portion is not continuous with the image 10 of the component electrode portion. Therefore, the height positions of the component electrode part 1 and the solder part 2 relative to the printed circuit board 3 can be grasped, and the image 1 of the solder part can be determined for each soldering state.
1 is different as shown in FIG. 5(a) and (+1)+(c), so the soldering state can be inspected from the vacancy of the image 11 of which part of the solder. 7(a) and 7(0) are configuration diagrams for inspecting the flat package component 13 having a J-type lead as shown in FIG. 6, and show the light source 4 and camera in FIGS. 1 and 2. Alternatively, change the arrangement of the light receiving area sensor 6, set the light source 4 diagonally above the component electrode (lead) part 1, the solder part 2, and the printed circuit board part 3, and place the light receiving area sensor or camera 6 next to the light source 4. It was installed. Figure 8 (a), (u), (c) are shown in Figure 7 (a), '(T
These are images obtained by the camera or light receiving area sensor 6 with the configurations of I) and '(C), and are shown in Figures 5(A) and (C).
El'), '(C), the image shown in Figure 8 (A) with normal solder, the image with a small amount of solder shown in Figure 8 (D), and the image shown in Figure 8 (H). ) The component electrode part (J
Different images are obtained depending on each soldering state, such as the image in which the solder is not wet on screen 13, and therefore the soldering state can be inspected based on the difference in the obtained glued images.

【Effect of the invention】

As described above, according to the present invention, the image obtained by the light-receiving area sensor is based on the soldering state and number j.
It reflects the solder shape, and based on this image, it is possible to reliably judge whether the soldering condition is acceptable or not.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a configuration for implementing the soldering inspection method according to the present invention, FIG. 2 is a perspective view of a configuration for inspecting parts different from that in FIG. 1, and FIGS. 3 and 4 are similar to those in FIGS. A perspective view of a configuration different from that shown in Figure 2, and Figures 5 (A) to (C) are the same as Figures 1 to 4.
Figure 6 shows the image obtained with the configuration shown in the figure. Figure 6 is a side view of the part with a J-type reed. Figures 7 (A) and (U) are the 6th
A perspective view and an elevation view of the configuration for inspecting the parts shown in the figure by the method of the present invention, and Figures 8 (A) to (C) are images obtained from the configuration of Figures 7 (A) and (D). FIG. ■Electrode part of one part, 2-Soldering part, 3-Printed circuit board, 4-Light source, 6-Light receiving area sensor or camera, 10
1 - Image of part electrode part, 11 - Image of soldering part, 12 - Image of printed circuit board.

Claims (1)

[Claims] 1) A slit light is irradiated on the electrode part or the soldered part at the end of a component mounted on a printed circuit board, an image is formed using the scattered light reflected by the soldered part, and judgments are made based on the image. A soldering inspection method for a mounted component, characterized in that the soldering state of the mounted component is inspected based on height information of the component and the soldered portion.