JPH0474915A - Observing apparatus for depression - Google Patents

Abstract

PURPOSE:To easily and positively detect the presence of a depression by applying an illuminating light of a second illuminating device to the surface of an object to be observed from above in the slantwise direction while a first illuminating device is turned ON. CONSTITUTION:A first illuminating device 22 is placed right above the observing position to illuminate the whole of a component 1 in a vertical direction. A second illuminating device 23 is provided slantwise above the observing position, with casting an illuminating light slantwise in the downward direction towards the surface of the component 1. The illuminating intensity or the distance from the observing position of each illuminating device 22, 23 are set so that the brightness on the surface of the component 1 by the illuminating light of the second illuminating device 23 is 2-several times higher than that of the surface of the component 1 by the illuminating light of the first illuminating device 22. An image sensing device 24 is positioned immediately above the observing position, the visual field of which is set in a vertical direction to the component 1.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a depression observation device for observing depressions such as marks and scratches existing on the surface of an object to be observed.

<Prior Art> For example, a surface mount type IC component has a form as shown in FIG. 6, in which a plurality of boards 3 protrude from both sides of a package part 2 made of synthetic resin. Each lead 3 is assigned a unique pin number, and a predetermined mark 4 is attached to the top surface of the package part 2 so that the first lead (hereinafter referred to as "first lead") 3a can be identified. be.

This mark 4 is a depression with a circular planar shape, and the bottom surface of this depression is either a flat mirror surface that specularly reflects light, as shown in FIG. 7 (1), or a flat mirror surface that specularly reflects light, as shown in FIG. 7 (2). It is a circular mirror surface that specularly reflects light. The mold for resin molding the package part 2 is provided with a protrusion for carving the mark 4 on the inner surface of the mold, and by polishing the surface of the protrusion, the surface of the mark 4 (the richness) is removed. The bottom surface) is formed into a smooth mirror surface. In the figure, numeral 5 is a printing section on which part numbers and the like are printed.

A plurality of components 1 having the above configuration are fixed on a strip tape 6 in the same direction at regular intervals and are supplied to a board assembly line or the like. As shown in FIGS. 6 and 8, this belt-shaped tape 6 has a structure in which an upper sheet 7 and a lower sheet 8 are overlapped, and the upper sheet 7 has through holes 9 at each fixing position of the component 1. An adhesive coating surface 10 is formed on the upper surface of the lower sheet 8, and the adhesive coating surface 10 is exposed in each through hole 9, and the adhesive force of the coating surface 10 is used to attach the component 1.
The bottom surface of the is fixed.

<Problems to be solved by the invention> However, when mounting each component 1 on the strip tape 6,
If the component 1 is mounted in the wrong direction, when the component 1 is taken out from the strip tape 6 and automatically mounted on a board, proper mounting will not be carried out, leading to malfunction of the circuit.

Therefore, before taking out part 1 from strip tape 6,
It is necessary to check whether the orientation is appropriate. Conventionally, to automate this type of inspection, focusing on the fact that the surface of the mark 4 is a mirror surface, irradiating light onto the surface of the part 10,
The mark 4 is detected by detecting the specularly reflected light from the mark 4.
Attempts have been made to determine the position of the component 1, that is, the orientation of the component 1.

However, if the polishing condition of the mold is uneven, the mark 4
The amount of specularly reflected light is not always constant because the mirror state of the mirror varies. Furthermore, since each component 1 cannot always be supported in the same horizontal state on the strip tape 6, the direction of specularly reflected light is not constant, and it is not easy to detect it reliably. For this reason, it has been considered difficult to put into practical use a device that automatically inspects the orientation of the component 1.

The present invention has been made in view of the above problem, and an object of the present invention is to provide a depression observation device that can reliably observe depressions such as marks and scratches existing on the surface of an object to be observed.

<Means for Solving the Problems> The present invention is a depression observation device for observing depressions existing on the surface of an object to be observed at a predetermined observation position. a first illumination device for illuminating the entire object from a vertical direction; a second illumination device located diagonally above the observation position and projecting illumination light diagonally downward toward the surface of the observation object; It consists of an imaging device that is positioned directly above the observation target and has a vertical field of view toward the observation target. And the first. Each of the second lighting devices has an illumination intensity such that the brightness of the surface of the observation target caused by the illumination light of the second lighting device is sufficiently greater than the brightness of the surface of the observation target caused by the illumination light of the first lighting device. Or the distance from the observation position is set.

<Operation> When the illumination light of the second illumination device is irradiated diagonally from above onto the surface of the observation target under the illumination of the first illumination device, the second illumination device always appears at the position of the depression due to the step of the depression. This results in a dark area that is not illuminated by the illumination light from the lighting device. By detecting this dark area on the image, the location of the depression can be determined.

<Example> FIG. 1 and FIG. 2 show the appearance of a component inspection device in which the present invention is implemented.

This component inspection device inspects components 1 in the form shown in FIG. parts l
At the same time, it is inspected whether or not the parts 1 are deviated from their predetermined fixed positions, whether the printing on each part 1 is good, and whether each lead 3 of each part 1 is not deformed.

Each component 1 to be inspected is fixed on the strip-shaped tape 6 at regular intervals with the adhesive-applied surface 10 described above. This strip tape 6 has holes 11 for feeding operation provided at a predetermined pitch on both edges, and a feed mechanism (not shown) is connected to the holes 11 to sequentially feed the strip tape 6 to place each component 1 at a predetermined observation position. (inspection position).

The component inspection device includes a light source 21. The first lighting device 22, the second
lighting device 23. The configuration includes an imaging device 242, an image processing device 25, and the like.

A halogen lamp or the like is used as the light source 21, and the light source 21 and the first . Each second illumination device 22.23 is optically coupled via an optical fiber 26.27.

The first illumination device 22 is located almost directly above the observation position,
The entire part 1 is illuminated from the vertical direction. In this embodiment, a ring light source formed by arranging a plurality of optical fibers optically coupled to the optical fiber 26 in a circle is used as the first illumination bag W22. The first illumination device 22 consisting of this ring light source is positioned around the imaging device 24 at its center and provides uniform illumination to the component 1.

The second illumination device 23 is located diagonally above the observation position,
Illumination light is projected diagonally downward toward the surface of the component 1. In this embodiment, as the second illumination device 23, a spot light source consisting of one optical fiber optically coupled to the optical fiber 27 or a plurality of bundled optical fibers is used. The second illumination device 23 consisting of this spot light source is positioned to the side of the observation position and provides spot illumination toward the component 1 at a predetermined angle θ.

1st. Each of the second lighting devices 22 and 23 is configured such that the brightness (illuminance) of the surface of the component 1 caused by the illumination light of the second lighting device 23 is higher than the brightness (illuminance) of the surface of the component 1 caused by the illumination light of the first lighting device 22 (
Each illumination intensity or distance from the observation position is set so that it is two to several times higher than the illumination intensity (illuminance).

The component 1 has a structure in which a plurality of leads 3 protrude from the outer periphery of a package part 2 made of synthetic resin, and a recess-shaped mark 4 is provided on the top surface of the package part 2 to confirm the first lead. , a printed part 5 in which necessary parts information is displayed in white.
and is provided. Further, an edge portion 12 formed of an oblique inclined surface is provided on the outer peripheral edge of the package portion 2.

The projected illumination light is diffusely reflected on the surface of the package portion 2, but the illumination light is specularly reflected on the mark 4, similarly to the lead portion 3 which is made of metal.

The imaging device 24 is located directly above the observation position, and its field of view is set in the vertical direction toward the component 1.

The video signal of the image obtained by the imaging device 24 is sent to the image processing device 25.
After the binarization process, a component inspection of a plurality of items is performed by setting a window WI-W, which will be described later, on the binary image. In the figure, 28 is a monitor television for displaying binary images and the like.

In the component inspection apparatus having the above configuration, when illumination light is simultaneously projected onto the component 1 to be inspected by the first and second illumination devices 22 and 23, as shown in FIG. The illumination light A 22 is diffusely reflected on the surface of the package part 2 and specularly reflected on the surface of the lead part 3. Further, when the illumination light B of the second illumination device 23 reaches the position of the mark 4,
Due to the step difference in the recess, a dark area 13 is created where the illumination light B is not applied.

FIG. 4 shows the brightness distribution of a grayscale image obtained by the imaging device 24 under such illumination, in correspondence with each part of the component 1. According to the figure, the lead part 3 is the brightest;
Next, the printed part 5 is bright, and then the upper surface of the package part 2 and the area other than the dark part 13 of the mark 4 are bright. The dark portion 13 of the mark 4 and the border portion 12 of the package portion 2 are the darkest images.

A plurality of binarization thresholds TH, -TH4 with different levels are set for this grayscale image, and FIG. 5 (1) to
(4) shows a binary image of a proper part when binarized at each binarization threshold TI (+ to Tl14).

In FIG. 5, diagonal lines indicate image areas with black pixels, and other lines indicate image areas with white pixels.

In Fig. 5 (1), 13' is in the dark part 13 of mark 4, 12
' corresponds to the border 12 of the package part 2, and only these image areas 13'' and 12'' are black pixels.

In FIG. 5(2), 2' corresponds to the package part 2, and 5' corresponds to the printing part 5, where the image area 2' of the package part is a black pixel and the image area 5' of the printing part is a white pixel.

In FIG. 5(3), 2' is the package part 2, and all of the image area 2' are black pixels.

In FIG. 5(4), 3' is the lead portion 3, and only this image area 3' is a white pixel, and the other image area 1' is a black pixel.

First, for the binary image shown in FIG. 5(1), a window W1 of a size including the dark image area 13' is set, and the number of black pixels in the window WI is counted. The presence or absence of the mark 4, that is, whether or not the orientation of the component 1 is appropriate, is determined based on whether the value is larger than a threshold value (a value close to zero). Next, for the same binary image, set a window w2 of a size that includes the image area 12'' of the border part, and count the number of black pixels in the window W2 to determine whether part 1 is missing. Discern.

Next, for the binary image shown in FIG. 5(2), a window W of a size including the image area 5' of the printing section is created.

By setting the number of black pixels (the number of white pixels) in the window W, it is determined whether the printing condition is good or not, and whether there are any missing prints.

Next, for the binary image shown in FIG. 5(3), a window W4 is set on the outer periphery of the image area 2' of the package part 2, and the number of black pixels within the window W4 is counted to locate the component 1. Determine whether there is any deviation.

Next, for the binary box image shown in FIG. 5(4), line windows WS, W,
By setting and measuring the pitch of each image area 3', it is determined whether or not the lead portion 3 is deformed.

Note that the window setting method described above is an example, and it goes without saying that component inspection can be performed using other window setting methods. In addition, the inspection items for components are not limited to those mentioned above, and inspection for chipping of the package portion 2, for example, can also be added to the inspection items.

<Effects of the Invention> As described above, the present invention uses the first illumination device and the second illumination device, and illuminates the surface of the observation target with the illumination light of the second illumination device under the illumination of the first illumination device. On the other hand, since the light is irradiated diagonally from above, if a depression exists in the observation target, a dark area will appear at the position of the richness, making it possible to easily and reliably identify the presence of the depression. Furthermore, when the dent observation device of the present invention is implemented in a parts inspection device, in addition to detecting dents, missing parts 9
Misalignment of parts, printing defects.

This has the advantage that deformation of the lead portion can also be inspected at the same time.

[Brief explanation of drawings]

FIG. 1 is an external view of a parts inspection device in which this invention is implemented;
Figure 2 is a front view of the parts inspection device, Figure 3 is an explanatory diagram showing the lighting conditions for parts, Figure 4 is an explanatory diagram showing the brightness distribution of gray images of departments, and Figure 5 is a binary value with different levels. An explanatory diagram showing each binary image when binarized using the conversion threshold, Fig. 6 is an oblique view showing the part to be inspected, Fig. 7 is a cross-sectional view showing the shape of the mark, and Fig. 8 is the tape strip. FIG.

Claims (1)

[Claims] A depression observation device for observing depressions existing on the surface of an observation target at a predetermined observation position, the device being located almost directly above the observation position and illuminating the entire observation target from the vertical direction. a first illumination device located diagonally above the observation position and projecting illumination light diagonally downward toward the surface of the observation target; and a second illumination device located directly above the observation position an imaging device whose field of view is set in a vertical direction toward the observation target, and each of the first and second illumination devices is configured such that the brightness of the surface of the observation target by the illumination light of the second illumination device is the same as that of the first illumination device. A depression observation device in which the illumination intensity or distance from the observation position is set to be sufficiently greater than the brightness of the surface of the observation target due to the illumination light of the illumination device.