JPH0820373B2 - Visual inspection method for electronic components with leads - Google Patents

Description

The present invention relates to a visual inspection method for electronic components with leads.

(Prior Art) When an electronic component is mounted on a substrate by an electronic component mounting device, the electronic component is likely to be displaced. For this reason,
After mounting, the electronic parts are subjected to a visual inspection, and those having a positional deviation of an allowable value or more are excluded from the line as defective products. As such a visual inspection method, the method described in JP-A-62-239040 is known. As shown in FIG. 3, in particular, this method irradiates an electrode such as a lead of an electronic component with light obliquely from above, and obtains image data of the edge (shoulder) of the electrode by an upper camera. The visual inspection of electronic components is performed by analyzing image data.

(Problems to be Solved by the Invention) By the way, as an electronic component, a leaded electronic component in which a large number of leads in four directions extend from a mold body is known. In recent years, the demand for higher integration and higher density is increasing, so in this type of electronic component with leads, the number of leads is gradually increasing, and the width of the leads is becoming smaller and the pitch is becoming narrower. As a result, the required mounting accuracy is also increasing.

When the appearance inspection of the electronic components with leads with such a narrow pitch is performed by the above-mentioned conventional method, the edges (shoulders) of the leads
Has a problem that the inspection accuracy does not increase because it shines too strongly due to the illumination light.

Therefore, an object of the present invention is to provide a visual inspection method for electronic components with leads, which can accurately perform visual inspection of electronic components with leads having a large number of leads with a narrow pitch in four directions.

(Means for Solving the Problem) For this purpose, the present invention irradiates light from an upper light source,
The horizontal tip of the lead grounded to the board is optically scanned by the upper camera in the width direction to detect a plurality of bisectors that bisect the high-brightness portion and divide them into two halves. Based on this, it is determined whether or not the electronic component is displaced.

In addition, light is emitted from diagonally above the back of the electronic component with leads,
The wall surface of the mold body was observed with a camera obliquely above and forward, and the presence or absence of electronic components was inspected based on the high brightness of the observation. In addition, combining the above two appearance inspection methods,
The electronic parts are checked for missing parts and misalignment.

(Operation) According to the above configuration, the appearance inspection of the leaded electronic component having a large number of leads having a narrow pitch in four directions can be accurately performed.

(Example) Next, the Example of this invention is described, referring drawings.

FIG. 1 is a side view of an appearance inspection apparatus for electronic parts according to an embodiment of the present invention, and FIG. 2 is a plan view of the electronic parts. In FIG. 1, reference numeral 11 is an electronic component mounted on a substrate 2, on which a camera 3 and a ring-shaped light source 4 are arranged.
Reference numeral 5 denotes a control device such as a computer connected to the camera 3. The electronic component 11 is an electronic component with leads such as an IC, and the leads L are bent and extended in a key shape in four directions from four sides of the box-shaped molded body 4. The molded body 12 is formed of a material having low brightness such as black synthetic resin, while the lead L is formed of a metal material having high brightness. The lead L has a hook shape, and has a horizontal base end portion a, a bent portion b, a steep descending slope portion c, and a horizontal front end portion d that is in contact with the substrate 2. In FIG. 2, many leads L extend straight from four sides of the molded body 12. In the figure, in order to distinguish the leads L, the leads L are denoted by reference numerals 1 to 8.

The appearance inspecting apparatus of the present electronic component has the above-mentioned configuration. Next, the appearance inspecting method of the electronic component will be described. Electronic parts
In inspecting the positional deviation of 11, the light source 4 is turned on to irradiate the leads L with light obliquely from above, and each lead L is observed by the upper camera 3. Then, the bent portion b is observed as a strong shining portion, the tip portion d shines slightly weaker than this, and the inclined portion c having a gradient reflects almost all the light to the side, and almost all reflected light is incident on the camera 3. No, and is therefore darkly observed by the camera 3.

Since the number of leads L of the electronic component 11 is large, the lateral width W of each lead L is considerably small, and therefore, the area of the high brightness portion of the bent portion b is small, so that it is difficult to accurately detect the center of gravity thereof. is there. Moreover, this electronic component 11 has four
Generally, a considerably high mounting accuracy is required in the direction. Therefore, this product undergoes an appearance inspection by the method described below.

When the lead L is irradiated with light obliquely from above and observed by the camera 3, the horizontal tip portion d grounded on the substrate 2 as described above is slightly bright. Therefore, as shown in FIG. 2, the leads L1 to L8 at both end portions of each side are selected as inspection targets, and optical scanning in the width direction is performed for each tip portion d to divide the high brightness portion into two equal parts. The bisected points M1 to M8 are detected and these points M1 to M8 are used as inspection points. 1 to 18 are scan lines. Then, each of the points M1 to M8 is compared with the reference points M1 'to M2', which are preset bisecting points of the master, to determine whether the positional deviation is acceptable or not. The second
In the figure, because the drawing becomes complicated, inspection point M3 ~
M8 and reference points M3 'to M8' are omitted.

The above inspection does not necessarily have to be performed for a large number of leads, and it is sufficient to select some of them and the number thereof is determined from the required mounting accuracy and the like. As described above, it is easier to perform the optical scanning by selecting the leads L1 to L8 at both end portions of each side.
In addition, high accuracy can be expected. In this way, the inspection points are
It is set arbitrarily according to the type of electronic component. In addition, each of the above-mentioned methods has a steep sloped portion c of the lead that bends in a hook shape.
When the light is emitted to the side, the light is reflected laterally, so that it is observed dark by the upper camera 3, and the boundary with the horizontal tip portion d next to it is clear. Therefore, the inspection point can be accurately positioned at the tip portion d. This is because it is easy to set.

FIG. 3 shows an out-of-stock inspection for inspecting the presence / absence of electronic components, which is preferably performed before the above-mentioned displacement inspection. As shown in the figure, in this lacking product inspection, light is emitted from obliquely above the back of the electronic component 11, and the wall surface S of the molded body 12 is observed by the camera 3 obliquely above and forward. If the observation brightness is low, it means that the black mold body 12 having low brightness is observed, and it is determined that the electronic component 11 exists there, and subsequently, the above-described displacement inspection of the electronic component is performed. If the observation brightness is high, it means that the substrate surface 2a was observed,
There is no molded body 12 there, and it is determined that the electronic component 11 is out of stock, and in this case, the above-described positional deviation inspection of the electronic component is not performed, and it immediately becomes NG.

(Effect of the Invention) According to the present invention, the appearance of a leaded electronic component with a narrow pitch can be swiftly and highly evaluated by utilizing the light reflection characteristics of the lead bent and extended in a key shape from the mold body. Can be done with precision. Further, by utilizing the light reflection characteristic of the molded body that the brightness is low, it is possible to accurately carry out the defective product inspection for the presence or absence of the electronic component.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention. FIG. 1 is a side view of a visual inspection apparatus for electronic parts, FIG. 2 is a plan view of electronic parts under inspection, and FIG. FIG. 3 is a side view of the electronic component of FIG. 2 ... Substrate 3 ... Camera 5 ... Control device 11 ... Electronic parts 12 ... Molded body L ... Lead M1 to M8 ... Inspection points M1 'to M8' ... Reference points

Claims (3)

[Claims] 1. A method for inspecting the appearance of a leaded electronic component, wherein leads are bent and extended in a key shape in four directions from a molded body mounted on a substrate, and light is emitted from an upper light source.
The horizontal tip of the lead grounded to the substrate is optically scanned in the width direction by the upper camera to detect a plurality of bisectors that bisect a high-luminance portion. A visual inspection method for an electronic component with a lead, comprising determining whether or not a positional deviation of an electronic component is acceptable based on a minute point. 2. A method for inspecting the appearance of a leaded electronic component, wherein leads are bent and extended in a key shape in four directions from a molded body mounted on a substrate, wherein the leaded electronic component is exposed from obliquely above its rear surface. A method for inspecting the appearance of electronic components with leads, characterized by observing the wall surface of a mold body with a camera obliquely above and observing, and inspecting for the presence or absence of electronic components based on the high brightness of the observation. 3. A method for inspecting the appearance of a leaded electronic component, wherein leads are bent and extended in a key shape in four directions from a molded body mounted on a substrate. And observe the wall surface of the mold body with a camera obliquely above the front, and inspect for the presence or absence of electronic parts based on the height of the observed brightness, and then irradiate light from an upper light source, The horizontal tip that is grounded on the board is optically scanned in the width direction by the upper camera to detect a plurality of bisectors that bisect the high brightness portion.
A method for inspecting the appearance of an electronic component with a lead, comprising determining whether or not a positional deviation of an electronic component is acceptable based on equal points.