JPH08184410A - External view inspection tool for electronic device - Google Patents

Abstract

PURPOSE: To obtain an external view inspection tool for electronic device in which an edge can be detected accurately at a part to be inspected even when the part to be inspected has a light reflecting action similar to that at other part and the dimensions of the edge can be determined accurately. CONSTITUTION: A device P to be inspected is irradiated with light from each illuminator 2 making an angle of 60 deg. against the image pickup direction so that a contrast, e.g. a shade, is provided positively at the edge of an electrode part when an image is picked up. With such arrangement, the edge position at the electrode part can be detected accurately from an image signal containing a contrast even when the electrode part has a light reflecting action similar to that of the housing part and the dimensions of the edge can be determined accurately.

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 performing dimensional inspection of an inspected portion of an electronic component, for example, an electrode portion provided on the surface of the component by image processing.

[0002]

2. Description of the Related Art An electronic component having an electrode portion on its surface, for example, an electrode portion Pg having a predetermined thickness made of a metal film on both end faces and around the end portion of a main body element Ps, and surrounding the main body element between the electrode portions Pg. Both end parts of the columnar part P1 (see FIG. 5A) or the prismatic part P2 (see FIG. 5B) having the outer part Pj made of resin, glass or the like in the annular recess formed in Whether or not the axial dimension of the electrode portion Pg formed at is within a predetermined non-defective range is inspected as one item on the appearance.

The appearance inspection apparatus shown in FIG. 6 is generally used for the above-mentioned dimension inspection. The inspection part P is conveyed to a position directly below the CCD camera 11 in a horizontal state, and is imaged while being illuminated by a ring-shaped illuminator 12 provided at the tip of the camera. The image signal from the camera 11 is taken into the image memory 13a of the image processing device 13, and the processing determination unit 1
In 3b, a predetermined inspection process, here, preprocessing of the image signal, edge detection, dimension measurement of the electrode part, and its quality determination are performed. The inspection result is displayed on the CRT 14 together with the input image, and the part corresponding to the dimension defect is removed after the inspection.

The procedure of the dimension inspection of the electrode portion Pd which has been generally performed conventionally will be described below with reference to FIG. The upper side of the figure shows the input image I of the camera 11, where Ih is the background image, Ip is the component image, Ipd is the electrode portion of the component image Ip, and Ip is the component image Ip.
pj is the exterior part of the component image Ip, and Ipb is the boundary between the electrode part Ipd and the exterior part Ipj (inner edge of the electrode part Ipd). The lower side of the figure shows luminance data in the X-X line direction in the input image I, where GIpd corresponds to the electrode region and GIpj corresponds to the exterior region. Here, the electrode portion Pd is the exterior portion Pj.
It is easier to reflect light than the electrode area GIpd and the exterior area G
It is shown that there is a significant difference in the brightness of Ipj.

When the dimension of the electrode portion Pd is inspected, luminance data is searched from the central position in the longitudinal direction of the component image Ip toward both electrode portions Ipd, and the rising position (inner edge position) where the luminance value changes to the high value side. To detect. Next, the length Lg from the above-mentioned detection position to the end face of the component is determined and used as the axial dimension of the electrode portion Pd. The above dimension measurement is X-
The X-rays are sequentially repeated in the width direction of the component image Ip (vertical direction in the drawing) while shifting in pixel units, and it is determined whether or not these are within a predetermined non-defective product range, and the pass / fail determination is performed.

[0006]

By the way, in some electronic parts, the exterior portion Pj has the same light reflecting action as the electrode portion Pd due to the material and color of the exterior portion Ps. In the conventional device described above, the inspection component P is only irradiated with light from the same direction as the image capturing direction. Therefore, when such component is imaged, the obtained brightness data shows the brightness as shown in FIG. However, the edge position of the electrode portion Pd cannot be detected by the above-described inspection method from such luminance data. Exterior part P
Even when a component in which the main body element Ps is exposed without j is to be inspected, the same problem occurs when the main body element Ps has the same light reflecting action as the electrode portion Pd.

The present invention has been made in view of the above problems, and an object thereof is to provide an edge position of an inspected portion even when the inspected portion and other portions have the same light reflecting action. It is an object of the present invention to provide a visual inspection apparatus for electronic components, which can accurately detect the above and accurately perform the dimension inspection thereof.

[0008]

In order to achieve the above object, the invention according to claim 1 detects an edge of a portion to be inspected in an electronic component, measures the dimension of the portion to be inspected based on the edge position, and judges its quality. In an appearance inspection apparatus for electronic parts, the image input means for picking up an image of the inspection part from a predetermined direction, the illuminating means for separately irradiating the inspection part with light from at least two directions forming an acute angle with the imaging direction, and an illuminating means. Image pickup control means for activating the image input means for each light irradiation for each direction according to the direction, and edge position detection means for detecting the edge position of the electrode portion based on the image signal obtained for each light irradiation. It is characterized by

According to a second aspect of the invention, in the appearance inspection apparatus according to the first aspect, the edge position detection means detects the edge position by comparing the brightness values of the image signals obtained for each light irradiation. It has a feature.

According to a third aspect of the present invention, in the appearance inspection apparatus according to the first or second aspect, the direction of light irradiation from the illumination means is orthogonal to the edge of the portion to be inspected.

[0011]

According to the first aspect of the present invention, light is radiated to the inspection part separately from at least two directions forming an acute angle with the image pickup direction, so that the edge position of the inspected part is positively shaded. It is possible to obtain an image of a part having different light and dark edge positions by performing imaging for each direction of light irradiation by the illumination means. The edge position of the inspected portion is detected based on the image signal obtained for each light irradiation, and the dimension of the inspected portion and its quality determination are performed based on the edge position.

According to the second aspect of the present invention, the edge position of the inspected portion can be detected by comparing the luminance values of the image signals obtained for each light irradiation, that is, searching for a portion where the luminance difference mutually appears depending on the presence or absence of a shadow or the like. Done. Other functions are similar to those of the invention of claim 1.

According to the third aspect of the present invention, the light irradiation direction from the illuminating means is made orthogonal to the edge of the inspected part,
It is possible to add a clear contrast to the edge position of the inspected portion along the edge. Other functions are similar to those of the invention of claim 1 or 2.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the configuration of the essential parts of an appearance inspection apparatus according to the present invention. The inspection part P in FIG. 5 is shown in FIG.
Similar to (b), the main body element is provided with electrode portions of a predetermined thickness made of a metal film on both end surfaces and around the end portion, and a resin is provided in an annular recess formed around the main body element between the electrode portions. It has an exterior part made of glass or the like. Camera 1 is CCD
6 is the same as that shown in FIG. 6 in which the inspection part P is conveyed laterally to a position directly below the camera 1 and its axis Pa
An image is taken from a direction orthogonal to the.

The illuminator 2 is composed of a light source 2a such as an LED or a light bulb and a light reflecting plate 2b, and irradiates the inspection part P with light whose light distribution is as uniform as possible. The respective illuminators 2 are arranged symmetrically with the imaging center 1a of the camera 1 interposed therebetween, and the inspection parts P
The same amount of light is emitted from different directions by 180 degrees. The light irradiation direction A of the illuminator 2 on the left side of the figure and the light irradiation direction B of the illuminator 2 on the right side of the figure have the same angle (θa, θb) with respect to the imaging direction, respectively, and the electrode of the inspection part P It is orthogonal to the edge of the part. In the illustrated example, the light irradiation angles θa and θb are set to about 60 degrees, but both angles θ
Optimal numerical values of a and θb are experimentally selected from an acute angle range capable of adding a shade such as a shadow to the edge position of the electrode portion during imaging.

The above-mentioned camera 1 operates each time the light from each illuminator 2 is irradiated, images the inspection part P from the same direction, and outputs respective image signals to the same image processing device as in FIG. Hereinafter, a series of inspection procedures related to the dimension inspection of the electrode portion will be described with reference to the input image and luminance data shown in FIGS. 2 and 3 and the flowchart shown in FIG.

After the inspection part P is conveyed to a position directly below the camera 1, first, the inspection part P is irradiated with light in the direction A from the illuminator 2 on the left side of FIG. 1, and the camera 1 is operated in the same state. The inspection part P is imaged (steps ST1 and ST2 in FIG. 4).

Since there is a step at the boundary between each electrode part of the inspection part P and the exterior part due to the difference in thickness between them (here, the electrode part is slightly thicker), the above-mentioned A direction illumination shows the left side in the drawing. The step is not exposed to light, and as a result, a shadow is generated along the edge at the edge position of the electrode portion on the left side in the figure. On the other hand, since the step on the right side of the inspection component P in the drawing almost faces the light irradiation direction A, such a shadow does not occur, and conversely, it emits light brighter than the electrode portion and the exterior portion.

That is, the image I obtained by A-direction illumination is
As shown in the upper side of FIG. 2, a black line having the same color as the background image Ih is formed along the edge Ipb at the edge position of the left electrode portion Ipd in the component image Ip, and the edge position of the right electrode portion Ipd is A color development line that is brighter than the electrode portion Ipd and the exterior portion Ipj is provided along the edge Ipd.

Next, the inspection part P is irradiated with light in the B direction from the illuminator 2 on the right side of FIG. 1, and the camera 1 is operated in the same state to image the inspection part P (steps ST3 and ST in FIG. 4).
4).

Contrary to the illumination in the A direction, the above-mentioned illumination in the B direction does not hit the step on the right side in the figure, and as a result, a shadow is generated along the edge at the edge position of the electrode section on the right side in the figure.
On the other hand, since the step on the left side of the inspection part P in the drawing almost directly faces the light irradiation direction B, such a shadow does not occur, and conversely, it emits light brighter than the electrode part and the exterior part.

That is, the image I obtained by B-direction illumination is
As shown in the upper side of FIG. 3, a black line having the same color as the background image Ih is provided along the edge Ipb at the edge position of the electrode portion Ipd on the right side of the component image Ip, and at the edge position of the electrode portion Ipd on the right side. A color development line that is brighter than the electrode portion Ipd and the exterior portion Ipj is provided along the edge Ipd.

Next, pre-processing such as noise removal and distortion correction is applied to the image signals obtained for each of the A-direction and B-direction light illumination,
Luminance data in the X-X line direction as shown in the lower side of FIG. 2 and the lower side of FIG. 3 are prepared for each pixel in the width direction of the component image Ip (FIG. 4).
Step ST5). Although the illustrated example shows that the preprocessing is performed after the imaging is performed twice, the preprocessing may be performed for each imaging.

Incidentally, in the brightness data of the A direction illumination shown in the lower side of FIG. 2, the electrode area GIpd and the exterior area GIpj have almost the same brightness, and the low brightness portion GIpl is also formed on the left side position corresponding to the shadow, and the color is also developed. The high brightness portion GIph is provided at the right side position corresponding to each part. In the brightness data of the B direction illumination shown in the lower side of FIG. 3, the electrode region GIpd and the exterior region GIpj have almost the same brightness, the low brightness part GIpl is located at the right side position corresponding to the shadow, and the color developing part is also located. Each of them has a high-luminance portion GIph at the left side position. In the luminance data on the drawing, the low luminance portion GIpl and the high luminance portion GI
Although ph is suddenly raised or lowered, the actual rising and falling of each part is gradual.

Next, the brightness values of the respective image data obtained by the A-direction illumination and the B-direction illumination are compared, a portion where a difference in lightness and darkness appears depending on the presence or absence of a shadow and a coloring portion is searched, and the edge positions of both electrode portions are searched. Is detected (step ST6 in FIG. 4).

Specifically, with the center in the longitudinal direction of the component image Ip as a reference point, one luminance data is used as a reference to search for a portion in the other luminance data that causes a luminance difference in the electrode direction, and the differences start to appear mutually. This is the edge position of the electrode part. This edge detection is sequentially repeated while shifting the X-X line in the width direction of the component image Ip in pixel units.

Next, the length from each edge position to the end face of the component is obtained and used as the axial dimension of each electrode portion (step ST7 in FIG. 4).

Next, it is determined whether or not the axial dimension of the electrode portion obtained in the above step is within a preset range of non-defective products, and the pass / fail judgment is performed, and the result is displayed on the CRT together with the input image. It is displayed (step ST8 in FIG. 4).

In the present embodiment, by irradiating the inspection part P with light forming an angle of about 60 degrees with the image pickup direction from each illuminator 2, the edge position of the electrode portion is positively shaded during each image pickup. Therefore, even if the electrode part and the exterior part have the same light reflecting effect, the edge position of the electrode part is accurately detected from the image signal including the above-mentioned light and darkness and the dimensional inspection is properly performed. Can be done.

Further, the edge potentials of the electrode portion are detected by comparing the luminance values of the image signals obtained for each irradiation of light in the A and B2 directions and searching for a portion where a luminance difference mutually appears depending on the presence or absence of a shadow or the like. Therefore, even if there is a low-luminance portion or a high-luminance portion other than the edge on the luminance data, it is possible to prevent this from being erroneously detected as an edge and improve the detection accuracy.

Further, by making the light irradiation directions A and B of the respective illuminators 2 orthogonal to the edges of the electrode portions, a sharp contrast along the edges is provided at the edge positions of the electrode portions to facilitate edge detection. It is possible to obtain various image signals.

In the above embodiment, the inspection part has the exterior part as an example, but it is needless to say that the same dimensional inspection can be performed even if the part has no exterior part and the main body element is exposed.

Further, as the inspection component, the one having the electrode portions at both ends of the component has been exemplified, but a component having the electrode portions at positions other than both ends of the component can be inspected. In this case, the shape of the electrode portion The arrangement of the illuminator that produces a shadow at the edge position according to

Furthermore, the number of illuminators does not necessarily have to be two, and may be increased appropriately according to the number of edges to be detected. Further, one that can separately emit light with different irradiation directions from one illuminator, for example, one that can change the light irradiation direction by changing the angle of the reflecting plate may be used.

In the above embodiments, the present invention is applied to the dimension inspection of the electrode portion. However, the dimension inspection of the portion to be inspected other than the electrode portion, for example, the dimension inspection of the exterior portion or the surface of the electronic component is performed. The present invention can be applied to the dimensional inspection of the raised portion and the recessed portion provided, and the same operation and effect can be obtained.

[0036]

As described above in detail, according to the first aspect of the invention, at least two different inspection directions are used for the inspection parts.
By irradiating light from the direction, the edge position of the inspected part is positively shaded at each image pickup time, so that the inspected part and other parts have the same light reflecting action. Even in such a case, it is possible to accurately detect the edge position of the portion to be inspected from the image signal including the light and dark and accurately perform the dimension inspection.

According to the second aspect of the present invention, the luminance values of the image signals obtained for each light irradiation are compared, and the edge potential of the inspected portion is searched by searching for the portion where the luminance difference mutually appears depending on the presence or absence of a shadow or the like. Therefore, even if there is a low-luminance portion or a high-luminance portion in a portion other than the edge on the luminance data, it is possible to prevent this from being mistakenly detected as an edge and improve the detection accuracy. The other effects are the same as those of the invention of claim 1.

According to the third aspect of the present invention, the light irradiation direction is made orthogonal to the edge of the inspected portion, so that the edge position of the inspected portion is provided with a clear light and dark along the edge to detect the edge. An easy image signal can be obtained.
Other effects are similar to those of the invention of claim 1 or 2.

[Brief description of drawings]

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

FIG. 2 is a diagram showing an input image and brightness data when illuminated in the A direction.

FIG. 3 is a diagram showing an input image and brightness data when illuminated in the B direction.

FIG. 4 is a flowchart showing an inspection procedure.

FIG. 5 is a perspective view of a cylindrical part and a prismatic part.

FIG. 6 is an overall configuration diagram of a conventional appearance inspection device.

FIG. 7 is a diagram showing a conventional input image and luminance data.

FIG. 8 is a diagram showing luminance data when the electrode portion and other portions have the same light reflecting action.

[Explanation of symbols]

P ... Inspection component, Pd ... Electrode part, Pj ... Exterior part, 1 ... Camera, 2 ... Illuminator, Ip ... Part image, Ipd ... Part image electrode part, Ipj ... Part image exterior part, GIpd ... Luminance data Electrode area, GIpj ... Luminance data exterior area, GIpl
... low brightness part of brightness data, GIph ... high brightness part of brightness data.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G01N 21/88 J G06T 7/00 1/00

Claims (3)

[Claims] 1. An appearance inspection apparatus for an electronic component, which detects an edge of a region to be inspected in an electronic component, and measures the dimension of the region to be inspected based on the edge position and judges whether the quality is good or bad. Image input means, illumination means capable of separately irradiating the inspection component with light from at least two directions forming an acute angle with the imaging direction, and the image input means is operated for each direction of light irradiation by the illumination means to perform imaging. An appearance inspection apparatus for an electronic component, comprising: an image pickup control means; and an edge position detection means for detecting an edge position of an electrode portion based on an image signal obtained for each light irradiation. 2. The appearance inspection apparatus for an electronic component according to claim 1, wherein the edge position detection means detects the edge position by comparing luminance values of image signals obtained for each light irradiation. 3. The appearance inspection apparatus for an electronic component according to claim 1, wherein the direction of light irradiation from the illumination means is orthogonal to the edge of the portion to be inspected.