JPH0743324B2 - Clinch condition detection method for component lead wires - Google Patents

Description

The present invention relates to a method for detecting a clinch state of a component lead wire of a board mounting component.

“Prior Art” Conventionally, a method for detecting the clinch state of a component lead wire of a component mounted on a board is generally as follows.
By obliquely illuminating the entire circumference from a shallow angle, incident light from the land near the mirror surface to the camera is eliminated and only reflected light from the protruding lead wire is obtained.

[Problems to be Solved by the Invention] However, since it is important to reduce the incident light from the land portion and the substrate is illuminated at a very shallow angle, sufficient reflection from the lead wire is obtained (third embodiment). (Figure) Illumination could not be performed and detection was unstable. (Fig. 4)
Also, the land part cannot be completely removed (noise remains). Further, in the case of the substrate with silk printing (FIG. 5), the lead wire and the silk printing overlap each other, resulting in the situation as shown in FIG. 6, and there is a problem that the accurate length cannot be measured.

[Means for Solving the Problems] In order to solve the problems described above, linearly polarized oblique illumination light on the substrate and linearly polarized epi-illumination that is polarized in the direction orthogonal to the polarized light of the oblique illumination. Illuminate with light and receive the reflected light in the same direction as the illuminated polarized light.
The quantized luminance is subtracted for each pixel at the corresponding position of the obtained image, and digital image processing is performed in which the subtracted result is 0.

[Working] With this method, the silk print can be reliably removed even when the silk prints overlap, and the image of the land part can be completely removed (no noise remains). Further, since the lead wire is also illuminated from the optimum angle, it can be detected stably.

[Example] An example of the present invention will be described below with reference to FIG.

The camera A1 and the camera B2 image the same field of view from the same direction by disposing the half mirror 7 and the mirror 8 in the optical path. The polarizing filters 5 and 6 attached to the front surfaces of the lenses 3 and 4 are adapted to transmit linearly polarized light having a 90 ° azimuth difference from each other, and the polarizing filter A5 is the polarized illumination emitted from the ring-shaped polarizing plate A10. The polarization filter B6 is equal to the azimuth angle and equal to the azimuth angle of the polarized illumination emitted from the ring-shaped polarizing plate B12.

The ring-shaped illumination A9 is an epi-illumination device, and is installed so that the specularly reflected light from the plane of the substrate enters the camera.

In particular, the land part has a very high brightness because it is close to the mirror surface.
Since the lead wire is not planar, almost no specular reflection light from the lead wire is incident on the camera, and since the silk screen is a diffusing surface, the brightness thereof is sufficiently lower than that of the land portion. That is, the ring-shaped illumination A has a role of detecting only the land portion excluding the portion covered by the lead wire. With FIG. 5 as the field of view, the image of camera A when only epi-illumination is used is as shown in FIG.

Further, the ring-shaped illumination B11 is an oblique illumination device from the optimum position of the lead wire reflection, and in the camera B that transmits this polarized light, the lead wire, the land portion, and the silk printing all have relatively even high brightness.

(FIG. 8) On the other hand, the image of the camera A in the case of only the oblique illumination is as shown in FIG.

This is because the lead wire and the land are both smooth enough to hold the polarization azimuth angle by reflection.
This is because silk printing has a complicated surface state and the polarization is eliminated at the time of reflection, so that the light including the light passing through the polarization filter A is included. Considering the image when the two lights are turned on at the same time, the camera B is
The camera A is as shown in FIG.

When the images obtained from the respective cameras are input to the digital image processing apparatus and the operation of subtracting the image of FIG. 10 from the image of FIG. 8 (luminance subtraction) is performed, and the pixel having a negative result is 0, The result shown in Fig. 11 is obtained, and an image is obtained in which only the noise-free lead wire is extracted.

[Advantages of the Invention] Conventionally, the land portion and the silk portion could not be detected with a sufficiently reliable clinch state of the component lead wire as noise, but the present invention completely removes the land portion and the silk portion. , It became possible to detect the clinch condition of the lead wire with high reliability.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of an embodiment of the present invention, FIG. 2 is an explanatory diagram of an illumination position, FIG. 3 is an image example obtained by illumination from an optimum illumination position, and FIG. An example of an image obtained by illuminating from a position where the incident light from the land is small, FIG. 5 is an example of a substrate with silk printing, and FIG. 6 is
An example of an image obtained by illuminating a silk-printed substrate from a position where the incident light from the land is small, FIG. 7 is an image of camera A obtained only by epi-illumination,
The figure shows an image of camera B obtained by illumination from an optimal illumination position, FIG. 9 shows an image of camera A obtained by illumination from an optimal illumination position, and FIG. 10 shows epi-illumination and optimal illumination position. The image of camera A, obtained by using both of the illuminations from Figure 11, Figure 11 is the resulting image.

Claims (1)

[Claims] 1. A method of irradiating a substrate with light and detecting the clinched state of a component lead wire of a component mounted on a substrate using the reflected light, comprising: a substrate, linearly polarized oblique illumination light; Polarized light is illuminated with linearly polarized epi-illumination light that is polarized in the orthogonal direction, and the reflected light receives the same direction component as the illuminated polarized light, and for each pixel at the corresponding position in the obtained image. A method for detecting a clinch state of a component lead wire, which comprises: performing a digital image process in which the quantized luminance is subtracted and the negative one is 0.