JPS62123339A - Soldering appearance inspection - Google Patents

Abstract

PURPOSE:To enable inspection of a defective soldering at a high speed and a high accuracy, by automatically correcting inspection areas correspondingly to a deviation in an electronic component soldered on a printed wiring board. CONSTITUTION:First, as shown by (C), initializing inspection areas S0a-S0c are previously set about solder land parts 13a-13c to be inspected. Under such a condition, a chip part 11 mounted as shown by (A), is irradiated with a light in such a manner as to brighten solder surface. Then, the image thereof is taken by an ITV camera and binary coded to brighten the solder part to obtain binary coded images S1a-S1c as shown by (B). Then, the coincidence between the binary coded images S1a-S1c and the initializing inspection areas S0a-S0c are detected by an pixel computing section to make the coincidence part new correcting inspection areas S2a-S2c. To detect defective soldering subsequently, features of a defective soldering, namely, poor soldering or the like in the correcting inspection areas S2a-S2c are extracted and charged varying lighting, filters and the like. Thus, the fast and highly accurate processing of only solder parts is made possible.

Description

[Detailed description of the invention] (Technical analysis) The present invention is a method for inspecting soldering defects such as insufficient solder or no solder on the soldering surface of a printed wiring board (printed circuit board) on which electronic components are mounted. This invention relates to a mounting appearance inspection method.

(Background Art) For example, when automatically inspecting the mounting soldering state of a printed wiring board on which electronic components such as tab components are mounted,
Conventionally, as shown in Figure 3 (a), a chip component 1
Inspection areas S, ~S0 are set in the soldering lands 13a to 13c of No. 1, and the lighting, filters, etc. are switched, and the I
The inspection area S is imaged with a TV camera or the like and subjected to image processing.

There is a method of determining whether there is a soldering defect within ~Sc. In addition, the same figure (b) is a side view seen from the arrow direction in (a), 10 is a printed wiring board, 12a-
12e is a lead terminal.

As one of the above inspection methods, as shown in FIG.
is detected by image processing, and □〉Defective standard...
...In the case of (1), there is a method of determining it as defective.

However, in the above method, the preset inspection area is fixed, so if the chip component 11 is misaligned as shown in FIG. 5, the image of the chip component 11 will enter the inspection area. , the area of the inspection area is no longer the area of only the soldered part, and the determination method of equation (1) has the drawback that -F does not improve the inspection accuracy. The same applies not only to this expression (1) but also to other inspection methods.

As a solution to the above-mentioned drawbacks, there is a method of measuring the amount of chip deviation using another method, as in the case of a chip with a two-pole terminal, and correcting the inspection area by the amount of deviation. However, this method has the disadvantage that it takes time to measure and correct because there are many variables such as the tilt and shape of the chip, and the accuracy is poor when inspecting a three-pole chip.

(Objective of the Invention) The present invention solves the above-mentioned problems and solves the problem of soldering failure. Handles that can be inspected with high precision and automatically at high speed
The purpose of this paper is to provide a method for visually inspecting the appearance of the parts.

(Disclosure of the Invention) The present invention will be described in detail below with reference to the drawings showing embodiments. Note that although the following description will be made using a chip component as an example, it goes without saying that other electronic components may be used.

FIG. 1 is a block diagram showing an embodiment of the present invention, which embodies the inspection method of the present invention. However,
The ITV camera 1 captures an image of the soldered portion of the printed wiring board-F, and the captured image 43 is binarized at a suitable binarization level in the binarization processing unit 2. Then, the pixel calculation unit 4 performs pixel calculation on the binarized image and the data in the initial setting inspection area memory unit 5 that is output in synchronization with the image signal, and the area where the two match is selected by the modified inspection area memory unit 6. to be memorized.

Next, the image processing section 3 performs image processing, and the determination processing section 7 performs determination processing, using the imaging signal at the time of inspection and the output of the modified inspection area memory section 6 synchronized with the signal.

The processing procedure will be explained in more detail below with reference to FIG.

As shown in FIG. 4(c), an initial setting inspection area S0. ~ Set Soc. In this state (a)
Illumination that brightens the solder surface, for example, diffused light, is applied to the chip component 11 mounted as shown in FIG. The captured image is binarized so that only the soldered part becomes brighter, and the image is binarized as shown in (b).
Valued image S1. ~S le is obtained. Then, the binarized images Sla to S1° and the initial setting inspection area S. ,~So
The pixel calculation unit 4 detects the matching portion of S2. ~S2c. Next, we changed lighting, filters, etc. to detect soldering defects.

Then, the correction inspection area S2. Characteristics of soldering defects in ~S2c, ie, insufficient solder, no solder, etc., are extracted and determined. Therefore, according to this method, information on only the soldered portion can be processed efficiently and at high speed.

(Effects of the Invention) As described above, according to the present invention, the inspection area can be automatically corrected in response to the misalignment of m-child components when inspecting the soldered portion of a printed wiring board that has been soldered. (a) Even if electronic components become misaligned, it is possible to detect soldering defects such as insufficient solder or no solder with high accuracy.

(b) Complex calculations are not required and high-speed processing is possible.

(c) Even complex-shaped inspection areas can be corrected with high precision, so initial settings can be made with a rough shape, improving work efficiency.

There are other effects.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment embodying the present invention, FIG. 2 is an explanatory diagram thereof, and FIGS. 3 to 5 are explanatory diagrams of a conventional appearance inspection method. 1... ITV camera, 2... Binarization processing section, 3
... Image processing section, 4 ... Pixel calculation section, 5.
Initial setting inspection area memory section, 6... Modified inspection area memory section, 7... Judgment processing section Applicant: Matsushita Electric Works Co., Ltd.

Claims (1)

[Claims] In the soldering appearance inspection of printed wiring boards that have been soldered, we irradiate the soldering area with a light that brightens the area, capture the image with an ITV camera, and convert it into a binarized image using a threshold value that makes the solder surface appear white. A soldering appearance inspection method characterized in that a part that coincides with a preset inspection area is set as a new inspection area, and various appearance inspections such as insufficient solder and no solder are performed within the inspection area.