JPH05256788A - Inspecting apparatus of external appearance of electronic component - Google Patents

Abstract

PURPOSE:To obtain an inspecting apparatus of external appearance of an electronic component which can determine properly whether the shape of the end part of a main body is good or bad. CONSTITUTION:An inspecting apparatus of external appearance which determine the appropriateness of the external appearance on the basis of a pattern P corresponding to the contour of an electronic component with leads is provided with a sampling means 4a which sets as a reference point the intermediate position between a parallel line A drawn at a position a little higher than the upper edge of the contour Pa of a lead and a parallel line At passing the vertex of the contour Pb of a main body and determines the contour coordinates of points a1 to a5 of intersection of a plurality of parallel lines A1 to A5 drawn at equal intervals through the reference point and above and below it and of the contour Pb of the main body, and with a function calculating means 4b which determines an approximation function equation from the sampled contour coordinates. Moreover, a boundary-point calculating means 4c which determines a point f1 of intersection of a straight line F1 or a curve obtained from the determined function equation and of the upper edge of the contour Pa of the lead, a comparing means 4e which compares the determined boundary point f1 with a reference boundary point, and a determining means 4j which determines the appropriateness of the external appearance on the basis of the result of comparison, are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a visual inspection apparatus for visually inspecting an electronic component with a lead, and in particular, inspecting a shape of an end portion of a main body by image recognition.

[0002]

2. Description of the Related Art A visual inspection apparatus of this type includes a camera for taking a two-dimensional image of an electronic component to be inspected and an image data.
It is composed of an image memory for storing the data and an image judging means using a microcomputer, for example, as shown in FIG.
As shown in FIG.
The appearance of an inductor, a capacitor or the like having the coaxial cable Cb on the same axis is inspected, and in particular, the quality of the coating shape at the boundary with the lead Cb is judged.

Now, a conventional determination method in the image determining means will be described. First, a pattern as shown in FIG. 6 which coincides with the contour of the part C is extracted, and then X where the diameter of the main body Ca is increased by a predetermined value α from the widths dL and dR of the left and right leads Cb. Find the length L between both positions from the coordinates,
Next, the length L thus obtained is compared with a reference length, and if the lengths L match within an allowable range, a non-defective product is determined, and if they do not match, a defective product is determined.

[0004]

However, in the conventional determination method, the length L is used as a guide for the quality of the shape.
When there is a protrusion Cc smaller than dL + α at the end as shown on the left side of FIG.
When the bulging portion Cd that is narrower than R + α is present at the end portion, the obtained length L matches the reference length within the allowable range, although the end portion shape of the main body Ca is defective. As a result, there is a drawback that the product is erroneously determined to be a good product.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an appearance inspection apparatus for an electronic component, which can appropriately determine the quality of the shape of the end portion of the main body.

[0006]

In order to achieve the above object, according to claim 1, a two-dimensional image of an electronic component having coaxial leads on both ends of the main body is imaged by an image pickup device, and the contour of the electronic component is obtained. In a visual inspection apparatus for electronic components that determines the quality of appearance of electronic components based on a pattern corresponding to the above, a parallel line drawn slightly higher than the upper edge of the lead contour and the apex of the main body contour are passed. Sampling means for determining the contour coordinates of the intersections of the body contour with a plurality of parallel lines drawn at equal intervals above and below the base point as a base point, and an approximate function formula from the sampled contour coordinates And a boundary point calculating means for obtaining an intersection of a straight line or a curve obtained from the obtained functional expression and the upper edge of the lead contour, and comparing the obtained boundary point with a reference boundary point. Based on the means and comparison results It is provided with determining means for determining appearance quality and are.

According to a second aspect of the present invention, in the visual inspection apparatus for an electronic component according to the first aspect, an intermediate position between a parallel line passing through an upper edge of the lead contour and a parallel line passing through an apex of the main body contour is used as a base point. Second sampling means for obtaining contour coordinates of the base point and intersections of a plurality of parallel lines drawn at equal intervals above and below the body contour and the body contour, and second function for obtaining an approximate function formula from the sampled contour coordinates The calculating means and the second comparing means for comparing the obtained constant of the functional expression with the reference constant are provided.

[0008]

In the appearance inspection apparatus according to the first aspect of the present invention, based on the pattern corresponding to the contour of the electronic component, first, the parallel lines and the main body contour drawn at a position slightly higher than the upper edge of the lead contour are drawn. The contour coordinates of the intersection of the main body contour and the base line and a plurality of parallel lines drawn at equal intervals above and below the base point are obtained with the intermediate position between the parallel lines passing through the vertices as the base point. Next, an approximate function formula is obtained from these contour coordinates, and an intersection (boundary point) between the straight line or curve obtained from the function formula and the upper edge of the lead contour is obtained. Next, this boundary point is compared with a reference boundary point obtained by measuring a non-defective product, and the appearance quality is judged based on the comparison result.

In addition to the above, the appearance inspection apparatus according to claim 2 is based on a pattern corresponding to the contour of the electronic component,
A midpoint between a parallel line passing through the upper edge of the lead contour and a parallel line passing through the apex of the body contour is used as a base point, and the intersection points between the base line and a plurality of parallel lines drawn at equal intervals above and below the body contour. The contour coordinates of are obtained. Next, an approximate function formula is obtained from these contour coordinates, the constant of the function formula is compared with a reference constant obtained by measuring a non-defective product, and the appearance quality is judged based on the comparison result. In this inspection apparatus, the determination of the appearance quality is double checked together with the comparison of the boundary point positions.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the structure of a visual inspection apparatus to which the present invention is applied. In the figure, C is a component with a lead such as an inductor and a capacitor, 1 is an illuminator for illuminating the component C from below, 2 is a camera for capturing a two-dimensional image of the component C, and 3 is image data. The image memory 4 is an image determination means using a microcomputer.

The component C that receives illumination from below is imaged by the camera 2 located above it, and the image data is stored in the image memory 3.

The image judging means 4 includes a first sampling section 4a, a first function calculating section 4b, and a boundary point calculating section 4c.
A reference boundary point memory 4d, a first comparing section 4e, a second sampling section 4f, a second function calculating section 4g,
Reference constant memory 4h, second comparison unit 4i, and determination unit 4
Based on the pattern corresponding to the part contour extracted from the image memory 3, the quality of the outer shape is determined by the procedure shown in the flowchart of FIG.

First, a parallel line A is formed at a position higher by Δd than the upper edge of the lead contour Pa of the pattern P, and the main body contour Pb.
The parallel lines At are set at positions passing through the vertices of (see ST1 of FIG. 2 and FIG. 3). Δd is a small value and is set appropriately according to the size of the component.

Next, the intermediate position of the parallel lines A and At is set as a base point, and parallel lines A1 to A5 are set at equal intervals above and below the base point (see ST2 and FIG. 3 in FIG. 2). Between the parallel lines A and At of the present embodiment, 20% and 35% of the space is provided.
And parallel lines A1 to A5 at the positions of 50%, 65% and 80%
Is set.

Next, the parallel lines A1 to A5 and the main body contour P
contour coordinates (Xa1, Ya) of intersection points a1 to a5 with b
1), (Xa2, Ya2), (Xa3, Ya3), (X
a4, Ya4), (Xa5, Ya5) are obtained (see ST3 of FIG. 2 and FIG. 3).

Next, the five sampled intersection points a1
From the contour coordinates a to a5, the linear function equations along these contour coordinates, here the slopes and intercepts of the functional equations, are calculated based on the following equations (ST4 in FIG. 2).

Slope of linear function = 2/5 (-Xa1-1 /
2Xa2 + 1 / 2Xa4 + Xa5) intercept of linear function = 1/5 (Xa1 + Xa2 + Xa3 + X
a4 + Xa5) Next, the coordinates (Xf) of the intersection point f1 of the straight line F1 obtained on the pattern from the above linear function equation and the upper edge of the lead contour Pa.
1, Yf1) (see ST5 in FIG. 2 and FIG. 4).
This intersection f1 is the lead Cb and the body Ca of the component C.
It is a boundary point calculated from (exterior).

Next, the coordinates (Xf
1, Yf1) is compared with the coordinates of the reference boundary point obtained by measuring the non-defective product (see ST6 in FIG. 2).

The processes of ST1 to ST6 are not limited to the left contour of the part C shown in FIGS.
The same applies to the right contour of the part C.

If it is judged that the obtained boundary point f1 matches the reference boundary point within the allowable range, then the pattern is continued.
A parallel line B at a position passing through the upper edge of the lead contour Pa of
Further, parallel lines Bt are set at positions passing through the vertices of the main body contour Pb (see ST7 of FIG. 2 and FIG. 5).

Next, with the intermediate position between the parallel lines B and Bt as a base point, parallel lines B1 to B5 are set at equal intervals above and below the base point (see ST8 and FIG. 5 in FIG. 2). Between the parallel lines B and Bt of the present embodiment, 20% and 35% of the space is provided.
And parallel lines B1 to B5 at the positions of 50%, 65% and 80%
Is set.

Next, the parallel lines B1 to B5 and the main body contour P
Contour coordinates (Xb1, Yb) of intersection points b1 to b5 with b
1), (Xb2, Yb2), (Xb3, Yb3), (X
b4, Yb4) and (Xb5, Yb5) are obtained (see ST9 of FIG. 2 and FIG. 5).

Next, five sampled intersections b1
From the contour coordinates b5 to b5, the linear function equations along these contour coordinates, here, the slopes and intercepts of the functional equations are calculated based on the following equations (ST10 in FIG. 2).

Slope of linear function = 2/5 (-Xb1-1 /
2Xb2 + 1 / 2Xb4 + Xb5) Linear function intercept = 1/5 (Xb1 + Xb2 + Xb3 + X
b4 + Xb5) Next, the slope and the intercept of the obtained linear function formula are respectively compared with the reference slope and the reference intercept of the linear function obtained by measuring the non-defective product (see ST11 in FIG. 2).

When it is judged that the obtained inclination and intercept agree with the reference inclination and the reference intercept, respectively, within the allowable range, a non-defective product is determined (see ST12 in FIG. 2). If it is determined in ST6 or ST11 that they do not match within the allowable range, a defective product is determined (see ST13 in FIG. 2).

Although omitted in the flow chart of FIG. 2, the processing of ST1 to ST11 is performed on the right contour of the part C, and in fact, the parallel lines A, At, and A1 to A5 are changed to the right contour. Since it can be used for both, the processes of ST3 to ST11 are similarly performed.

As described above, in the present embodiment, the linear function formula along the contour coordinates is obtained from the coordinates of the five intersection points a1 to a5 obtained by sampling the main body contour Pb, and the line segment F1 of the linear function formula is obtained. Since the boundary point between the lead Cb and the main body Ca in the part C is obtained from the intersection f1 between the upper edge of the main body Ca and the upper edge of the lead contour Pa, this is compared with the reference boundary point. The protrusion Cc and the bulge C as shown in FIG.
Even if d is present, it is possible to accurately grasp the end shape by the obtained linear function formula and appropriately judge the quality of the end shape.

Further, a linear function equation along the contour coordinates is obtained from the coordinates of the five intersections b1 to b5 obtained by further sampling another position of the main body contour Pb, and the slope and intercept of the linear function equation are used as a reference. Since the slope and the reference intercept are compared respectively, the intersection point a obtained in the first sampling
Even if there is a minute shape change between each of 1 to a5, the end shape can be double checked by accurately grasping the shape change from the inclination and the intercept obtained here. Can be performed with higher accuracy.

The number of contour coordinate samplings in the above embodiment can be increased or decreased as appropriate, and the function formula obtained from the sampled contour coordinates may be a curve function formula. When used, each constant of the curve function formula may be compared with a reference constant. Further, a quintic equation obtained by the least-squares approximation method can be used for the latter determination, and the same determination can be performed by comparing each constant of the equation with a reference constant.

[0030]

As described in detail above, according to the appearance inspection apparatus of the first aspect, a functional expression along the contour coordinates is obtained from the coordinates of a plurality of intersections obtained by sampling the body contour, Since the boundary point between the lead and the body in the part is determined from the intersection of the straight line or curve obtained from the functional expression and the upper edge of the lead contour, this is compared with the reference boundary point. Even when there is a small protrusion or an elongated bulge at the end, the shape of the end can be accurately grasped by the obtained functional expression and the quality of the shape can be appropriately determined.

Further, according to the appearance inspection apparatus of the second aspect, a functional expression along the contour coordinates is obtained from the coordinates of a plurality of intersections obtained by further sampling different positions of the body contour,
Since the constant of the functional expression is compared with the reference constant, even if there is a minute change in shape between the intersections obtained in the first sampling, the shape of the shape can be calculated from the constant of the obtained functional expression. The change can be accurately captured to double-check the end shape, and the determination can be performed with higher accuracy.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an appearance inspection device to which the present invention is applied.

FIG. 2 is a flow chart showing a determination method.

FIG. 3 is a pattern diagram showing a sampling procedure.

FIG. 4 is a pattern diagram showing a procedure for obtaining a boundary point.

FIG. 5 is a pattern diagram showing a sampling procedure.

FIG. 6 is a component plan view showing a conventional determination method.

FIG. 7 is a top view of a component showing a defect in the conventional determination method.

[Explanation of symbols]

C ... parts, Ca ... main body, Cb ... lead, 2 ... camera, 3
... image memory, 4 ... image determining means, 4a ... first sampling section, 4b ... first function calculating section, 4c ... boundary point calculating section, 4e ... first comparing section, 4f ... second sampling section, 4g ... 2nd function calculation part, 4i ... 2nd comparison part, 4
j ... Judgment part, P ... Pattern, Pa ... Lead contour, Pb ...
Body outline, A, At, A1 to A5 ... Parallel lines, a1 to a5
... intersection, F1 ... straight line, f1 ... boundary point, B, Bt, B1 ...
B5 ... parallel lines, b1 to b5 ... intersections.

Claims (2)

[Claims] 1. A two-dimensional image of an electronic component having coaxial leads on both ends of a main body is picked up by an image pickup device, and the quality of appearance of the electronic component is judged based on a pattern corresponding to the contour of the electronic component. In the appearance inspection device for electronic parts, the intermediate point between the parallel line drawn at a slightly higher position from the upper edge of the lead contour and the parallel line passing through the apex of the main body contour is set as the base point, and Sampling means for obtaining contour coordinates of intersections of a plurality of parallel lines drawn at equal intervals and the body contour, function calculating means for obtaining an approximate function formula from the sampled contour coordinates, and straight line obtained from the obtained function formula Or a boundary point calculating means for obtaining an intersection between the curve and the upper edge of the lead contour, a comparing means for comparing the obtained boundary point with a reference boundary point, and a judging means for judging the appearance quality based on the comparison result. Provided that A visual inspection device for electronic parts. 2. An intermediate position between a parallel line passing through the upper edge of the lead contour and a parallel line passing through the apex of the main body contour is set as a base point, and a plurality of parallel lines drawn at equal intervals above and below the base point. Second sampling means for obtaining the contour coordinates of the intersection with the body contour, second function calculating means for obtaining an approximate function formula from the sampled contour coordinates, and first comparing the constant of the obtained function formula with a reference constant. 2. The appearance inspection apparatus for an electronic component according to claim 1, further comprising: a second comparison unit.