JPH0552534A - Inspecting apparatus of soldering - Google Patents

Abstract

PURPOSE:To enable execution of quick and accurate inspection in consideration of a change in a shape by a method wherein positions of reflected lights obtained by illuminators disposed on a circumference are expressed by polar coordinates from the basic position of an illuminator positioned vertically above. CONSTITUTION:The image of an electronic component which is soldered on a base and to the soldered part 14 of which lights of an illuminator 1 positioned vertically above and illuminators 2 to 7 disposed on a circumference obliquely above are applied is picked up by a TV camera 8. Positions of reflected lights are computed by a measuring means 11 from that image taken in an image memory 9. A determining means 12 expresses the positions of the reflected lights obtained by the illuminators 2 to 7, by the radiuses and deflection angles of polar coordinates around the position of the reflected light of the illuminator 1, and makes these radiuses and deflection angles be parameters showing the three-dimensional shape of the soldered part 14. Values of them are compared with ones in a set allowable range and the quality is determined. In this way, quantitative or qualitative determination is conducted and information for knowing an approximate shape can be processed at a high speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soldering inspection device for inspecting a soldering state of an electric device such as an electronic component mounted on a board from image information.

[0002]

2. Description of the Related Art As a conventional soldering inspection apparatus of this type, there is one disclosed in Japanese Patent Application Laid-Open No. 3-6447. In this method, four illuminations are arranged diagonally above the soldering portion, and the quality of soldering is determined based on the value of the area surrounded by the center of gravity of the reflected light.

An outline of this method is shown in FIG. In FIG. 5, 31 is a component, 32 is a solder portion, 33 is a mask region (broken line frame) set on a soldering land, 34, 35, 3
6 is an area where the soldering part is illuminated from three directions and shines brightly, 37, 38 and 39 are bright areas 34 and 3
Each of the barycentric values 5 and 36, 40 is a triangle having the three barycentric points as vertices in the case of a non-defective product, and 41 is a triangle having three barycentric points in the case of being defective.

As shown in FIG. 5, FIG. 5 (a) is a non-defective product, and the value of the enclosed area is large. On the other hand, FIG. 5B is a defective product, and the area value is small because the amount of solder is small. From this, it is possible to compare the size of this area with a threshold value for determination, and if it is larger than the threshold value, it can be determined as a good product, and if it is smaller than the threshold value, it can be determined as a defective product.

[0005]

However, the inspection method shown in the above-mentioned conventional example is effective in the case of checking the presence / absence of solder in the soldering in which the shape is relatively stable, but spot soldering or the like. It cannot be applied to soldering shapes that may change in various ways. This is because the position of the center of gravity of reflected light changes greatly when the soldering shape changes significantly, but it is often impossible to measure the shape change when only looking at the area. In order to judge the quality of such soldering, it is the most important task to grasp the three-dimensional shape of soldering from a plurality of lights at high speed.

[0006]

In order to achieve the above object, in the present invention, firstly, the position of the reflected light of the illumination above the soldering portion vertically is measured and set as the basic position of the soldering portion. The position of the reflected light of the illumination on the circumference is expressed by the radius vector and the polar angle from this basic position, and this value is used as a parameter indicating the three-dimensional shape of the soldered portion. If these values are within the range of the respective designated values, it is determined as a good product, and if not, it is determined as a defective product.

Secondly, in addition to the first means, the position of the reflected light of the illumination vertically above the soldering portion, that is, the basic position of the soldering portion is measured by a certain amount, and the deviation is measured. If the amount is large, it is regarded as defective.

Thirdly, as the illuminating means, a ring illuminator is arranged vertically above the soldering portion, and a plurality of ring illuminators are arranged obliquely upwardly on the circumference.

[0009]

According to the present invention, first, a plurality of illuminations on the circumference are applied to the soldering portion at different angles, and the reflected light position thereof is measured, whereby the inclination determined by the camera position and the illumination position of the image pickup means. Get the position of the face with. This allows
Although only information on a part of the soldering shape can be obtained, information that is important for knowing the outline can be processed at high speed. Further, unlike the area and the like, since the positional relationship of the directly reflected light is used as a material for the determination, it is possible to appropriately grasp the outline of the soldered portion.

Further, by using the reflected light position of the vertically upper illumination as the basic position and measuring the reflected light positions of the other illuminations relatively, even if the position of the soldered portion is entirely displaced, Does not affect shape measurement.

Further, since the illumination is arranged on the circumference, the shape of the soldered portion can be properly grasped by capturing the position of the reflected light in polar coordinates. And
Also, if symmetry is seen in the shape of the soldered part,
By expressing the allowable range of the reflected light position of the illumination in polar coordinates, the number of data expressing the shape can be reduced,
For example, when the soldering part is on a hemisphere, the data of the radius vector of the non-defective product is constant.

Second, in addition to the above, by comparing the reflected light position of the vertically upper illumination, which is the basic position, with the predetermined position, it is possible to detect the positional deviation of the entire soldered portion. According to this, even if the shape of the soldering portion is a good product, it is possible to remove a product whose position is displaced as a whole as a defective product.

Thirdly, since the soldering portion has a mirror surface and a fine structure, the correct surface cannot be measured by one illumination because of its local structure. The inclination of a surface is determined by three points in space, and in that sense the inclination of the surface must be grasped to some extent as a macro. In the present invention, by using ring illumination as the illumination, it is possible to obtain a certain degree of latitude in the irradiation angle and to stably obtain the reflected light. Further, the ring illumination has an advantage that it can be installed at a position where it normally interferes with the camera angularly.

[0014]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 is an illumination vertically above the soldering portion 14, 2 to 7 are a plurality of illuminations arranged on the circumference obliquely above the soldering portion 14, and 8 is a television camera which is a part of an image pickup means. , 9 is an image memory which is a part of the image pickup means, 10 is a control means for performing a series of control such as lighting control and image pickup control,
Reference numeral 11 is a measuring means for measuring the reflected light position from the contents of the image memory, 12 is a determining means, and 13 is a determination result.

Next, the operation will be described. In the inspection device configured in this way, the inspection procedure is as follows.
First, the illumination 1 is turned on by a command from the control means 10.
The image by this illumination is picked up by the television camera 8 and taken into the image memory 9, and then the reflected light position is calculated by the measuring means 11. As the calculation method of the reflected light position, the center of gravity of the binary image in a certain area may be obtained, or the particle analysis calculation by labeling may be used. Alternatively, the center of gravity of the grayscale image may be calculated. The calculation of the position of the reflected light is similarly performed for the illuminations 2 to 7, and after the positions of the reflected light by all the illuminations are calculated, the data is sent to the determination unit 12. The number of illuminations on the circumference is not limited to the six shown in this figure, but may be any number.

As shown in FIG. 2, for example, the judging section 12 sets an allowable range for the radius vector and the deviation angle, checks that the reflected light is in the range, and decides whether the result is good or bad. Output. In this case, the presence / absence of reflected light within the set allowable range is checked, which is a quantitative determination method. In FIG. 2, 15 is a lead part, and 16 to 22 are illuminations 1 to 7 in order.
, R _i and θ _i represent the radius vector and the deviation angle of the reflected light position of the illumination i (i is an integer represented by the symbols of the illuminations 1 to 7), and the hatched portion in the figure indicates the reflected light of the illumination 3. Within the allowable range of, the following ranges are provided. ^{_{r 3 * -δr 3 * ≦ r}} 3 ≦ r 3 * + δr 3 * θ 3 * -δθ 3 * ≦ θ 3 ≦ θ 3 * + δr 3 *

Embodiment 2. In the above-mentioned device configuration, the allowable range of the deflection angle of the determination unit 12 is not determined by a predesignated value,
It can also be determined by the arrangement of the reflected light positions. Figure 2
If the magnitude relationships of the deviation angles are matched, it is considered as a good product (when lighting 2 to 7 on the circumference are sequentially turned on, θ ₂ <θ ₃ <θ ₄
The determination unit 12 may be configured such that <θ ₅ <θ ₆ <θ ₇ ... At this time, it is not necessary to set the allowable range of the deviation angle, and qualitative determination can be performed.

Example 3. In the method described in the first embodiment, all the reflected light positions of the illuminations 1 to 7 are obtained, and the determination is made based on the soldering shape. First, the reflected light position of the illumination 1 falls within a predetermined range. It is also possible to configure the measurement unit 11 and the determination unit 12 so that the defective product is removed first by checking whether or not the defective product is present. With this method, the soldering portion 14 that causes the overall positional deviation can be removed as a defective product.

Example 4. As shown in FIG. 3, the illuminations 2 to 7 may be ring illuminations. By doing so, the reflected light can be stably obtained. Also, FIG.
Alternatively, the ring illumination 24 and the camera 23 may be installed as a pair as shown in FIG. 3 and the number of cameras may be increased to obtain the position of the reflected light with high reliability.

[0020]

As described above, according to the present invention, firstly,
The position of the reflected light of the illumination above the soldering part is measured as the basic position of the soldering part, and the positions of the reflected light of the illumination on the other circumferences are expressed by the polar coordinate radius vector and declination angle from this basic position. Since this value is used as a parameter indicating the three-dimensional shape of the soldered portion to make a quantitative or qualitative determination, the soldering inspection in consideration of the shape of the soldered portion can be performed quickly and accurately.

Secondly, in addition to the first effect, by comparing the reflected light position of the vertically upper illumination, which is the basic position, with the predetermined position, the positional deviation of the entire soldered portion can be detected. .. As a result, the overall positional deviation of the soldered portion can be removed as a defective product.

Thirdly, the reflected light can be stably obtained by using the ring illumination as the illumination, and the reliability of the determination is improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a soldering inspection apparatus according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram of a quality determination method in a determination unit of the present invention.

FIG. 3 is a configuration diagram of a soldering inspection apparatus in which illumination is configured by ring illumination in the present invention.

FIG. 4 is an explanatory diagram showing effectiveness of ring illumination.

FIG. 5 is an explanatory diagram showing an example of an inspection method of a conventional soldering inspection device.

[Explanation of symbols]

1 Illumination above the soldering portion vertically 2 to 7 Plural illuminations arranged on the circumference diagonally above the soldering portion 8 Television camera 9 which is a part of the image pickup means 9 Image memory 10 which is a part of the image pickup means 10 Lighting control and Control means for performing a series of control such as imaging control 11 Measuring means for measuring the reflected light position from the contents of the image memory 12 Judgment means 13 Judgment result 14 Soldering part 15 Lead part 16 Reflected light from illumination 1 17 Reflected light from illumination 2 18 Reflected Light from Illumination 3 19 Reflected Light from Illumination 4 20 Reflected Light from Illumination 5 21 Reflected Light from Illumination 6 22 Reflected Light from Illumination 7 23 Camera 24 Ring Illumination

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[Procedure amendment]

[Submission date] August 6, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

Claims (3)

[Claims] 1. An illuminating means comprising an illuminator vertically above a soldering part of an electronic component soldered to a substrate and a plurality of illuminators arranged circumferentially obliquely above the soldering part, and the illuminating means. An image pickup means for picking up an image of the soldering part, a measuring means for measuring the position of the reflected light illuminated on the soldering part from the image of the soldering part, and a control for controlling the image pickup means, the measuring means, and the illuminating means Means and the position of the reflected light obtained from the plurality of illuminating means are represented by a radius vector and a deflection angle centered on the reflected light position of the illumination vertically above the soldering part, and those values are designated respectively. A soldering inspection apparatus comprising: a determining unit that determines whether the soldering is good or bad depending on whether or not the value is within a predetermined value. 2. The determining means compares the reflected light position of the illumination vertically above the soldering part with a predetermined position, and if the difference exceeds a threshold value, it is determined as defective. 1. The soldering inspection device according to 1. 3. The illuminating means comprises one ring illuminator vertically above the soldering part and a plurality of ring illuminators arranged obliquely above the circumference. Soldering inspection device.