JP3321503B2 - Appearance inspection equipment for electronic components - Google Patents

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 a portion to be inspected in an electronic component, for example, an electrode portion provided on the surface of the electronic 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 of a predetermined thickness made of a metal film on both end surfaces and around the end portion of a main body element Ps, and a peripheral portion of the main body element between the electrode portions Pg A cylindrical part P1 (see FIG. 5 (a)) or a prismatic part P2 (see FIG. 5 (b)) provided with an exterior part Pj made of resin, glass, or the like in an annular concave portion formed at both ends of the part. It is examined as an item on the appearance whether or not the axial dimension of the electrode portion Pg formed in the above is within a predetermined non-defective range.

In the above-described dimension inspection, an appearance inspection apparatus shown in FIG. 6 is generally used. The inspection component P is conveyed in a horizontal position to a position directly below the CCD camera 11, where an image is taken while being illuminated by a ring-shaped illuminator 12 provided at the end of the camera. The image signal from the camera 11 is fetched into the image memory 13a of the image processing device 13, and is processed by the processing determination unit 1.
In 3b, a predetermined inspection process, in this case, preprocessing of an image signal, edge detection, dimension measurement of an electrode portion, and quality determination are performed. The inspection result is displayed on the CRT 14 together with the input image, and components corresponding to dimensional defects are removed after the inspection.

[0004] Hereinafter, a procedure of dimensional inspection of the electrode portion Pd, which is conventionally generally performed, will be described with reference to FIG. The upper part 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 part of the component image Ip, I
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 (the inner edge of the electrode part Ipd). The lower side of the figure shows luminance data in the XX line direction of the input image I, where GIpd corresponds to the electrode region and GIpj corresponds to the exterior region. Here, the electrode part Pd is the exterior part Pj
It reflects light more easily than the electrode region GIpd and the exterior region G.
The case where a remarkable difference occurs in the luminance of Ipj is shown.

When inspecting the dimensions of the electrode portion Pd, luminance data is searched from the center position in the longitudinal direction of the component image Ip toward the two electrode portions Ipd, and a rising position (position of an inner edge) at which the luminance value changes to a higher value side. Is detected. Next, a length Lg from the above detection position to the component end face is obtained, and this is set as the axial dimension of the electrode portion Pd. The above dimension measurement is X-
The X-rays are sequentially repeated while shifting in the pixel direction in the width direction of the component image Ip (vertical direction in the drawing), and it is determined whether or not these are within a predetermined non-defective range to determine the quality.

[0006]

Some of the electronic components have the exterior part Pj having the same light reflecting function as the electrode part Pd due to the material and color of the exterior part Ps. In the above-described conventional device, the inspection component P is simply irradiated with light from the same direction as the imaging direction. Therefore, when such a component is imaged, the obtained luminance data has the brightness as shown in FIG. The edge position of the electrode portion Pd cannot be detected from such luminance data by the above-described inspection method. Exterior part P
Even when a component having no j and exposing the main body element Ps is to be inspected, the same problem occurs when the main body element Ps has the same light reflection function as the electrode portion Pd.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for detecting an edge position of a portion to be inspected even if the portion to be inspected has the same light reflection function. It is an object of the present invention to provide an electronic component appearance inspection apparatus capable of accurately detecting the size of the electronic component and accurately performing the dimensional inspection.

[0008]

In order to achieve the above object, according to the first aspect of the present invention, an edge of a part to be inspected in an electronic component is detected, and the dimension of the part to be inspected is measured based on the edge position and the quality of the part is determined. Input means for imaging the inspection component from a predetermined direction, illumination means for separately irradiating the inspection component with light from at least two directions at an acute angle to the imaging direction, and illumination means Imaging control means for operating the image input means for each light irradiation in each direction according to the direction, and an edge position detecting means for detecting an edge position of the electrode portion based on an image signal obtained for each light irradiation. It is characterized by that.

According to a second aspect of the present invention, in the appearance inspection apparatus of the first aspect, the edge position detection by the edge position detecting means is performed by comparing the luminance value of an image signal obtained for each light irradiation. Features.

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 illuminating means is orthogonal to the edge of the inspected portion.

[0011]

According to the first aspect of the present invention, light is separately radiated to the inspection component from at least two directions forming an acute angle with the imaging direction, so that the edge position of the inspected portion is actively shaded with a shadow or the like. It is possible to obtain a component image in which the edge position is different in lightness or darkness by taking an image every time light irradiation is performed in each direction by the illumination means. The detection of the edge position of the inspected part is performed based on an image signal obtained for each light irradiation, and the dimension measurement of the inspected part and the 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 brightness values of the image signals obtained for each light irradiation, that is, by searching for a portion where the brightness difference mutually appears depending on the presence or absence of a shadow or the like. Done. Other functions are the same as those of the first aspect.

According to the third aspect of the present invention, the direction of light irradiation from the illuminating means is made orthogonal to the edge of the inspected part,
It is possible to give clear light and shade along the edge to the edge position of the inspected part. Other functions are the same as those of the first or second aspect of the present invention.

[0014]

FIG. 1 shows the configuration of a main part of an appearance inspection apparatus according to the present invention. FIG. 5A shows the inspection component P in FIG.
It is the same as (b), having an electrode portion of a predetermined thickness made of a metal film on both end faces and around the end portion of the main body element, and forming a resin in an annular recess formed around the main body element between the electrode sections. An exterior part made of glass or the like is provided. Camera 1 is CCD
The inspection component P is transported in a horizontal state to a position directly below the camera 1 and its axis Pa
The image is taken from a direction orthogonal to.

The illuminator 2 is composed of a light source 2a such as an LED or a light bulb and a light reflector 2b, and irradiates the inspection component P with light whose light distribution is as uniform as possible. Each illuminator 2 is arranged symmetrically with respect to the imaging center 1a of the camera 1, and the inspection component P
Are irradiated with the same amount of light from different directions by 180 degrees. The light irradiation direction A of the illuminator 2 on the left side in the drawing and the light irradiation direction B of the illuminator 2 on the right side in the drawing have the same angle (θa, θb) with respect to the imaging direction. Perpendicular to the edge of the part. In the illustrated example, the light irradiation angles θa and θb are set to about 60 degrees.
The optimum numerical values of a and θb are experimentally selected from an acute angle range in which light and shade such as shadows can be added to the edge position of the electrode portion during imaging.

The camera 1 operates every time light is emitted from each of the illuminators 2 to capture an image of the inspection component P from the same direction, and outputs respective image signals to the same image processing apparatus as in FIG. Hereinafter, a series of inspection procedures related to the dimension inspection of the electrode unit 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 component P is transported to a position directly below the camera 1, first, the light in the direction A is irradiated on the inspection component P 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).

At the boundary between each electrode part and the exterior part of the inspection part P, there is a step due to the thickness difference between them (here, the electrode part is slightly thicker). The light does not hit the step, 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 drawing. On the other hand, since the step on the right side of the inspection component P in the drawing is almost directly opposite to the light irradiation direction A, such a shadow does not occur, and on the contrary, light is emitted brighter than the electrode portion and the exterior portion.

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

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

In the above-described B-direction illumination, light does not hit the right step in the figure, contrary to the A-direction illumination. As a result, a shadow is generated along the edge at the edge position of the right electrode portion in the figure.
On the other hand, since the step on the left side of the inspection component P in the drawing is almost directly opposite to the light irradiation direction B, such a shadow does not occur, and conversely, light is emitted brighter than the electrode portion and the exterior portion.

That is, the image I obtained by the B-direction illumination is
As shown in the upper part of FIG. 3, the component image Ip has a black line of the same color as the background image Ih along the edge Ipb at the edge position of the right electrode portion Ipd, and the black line at the edge position of the right electrode portion Ipd. Along the edge Ipd, it has a coloring line brighter than the electrode part Ipd and the exterior part Ipj.

Next, preprocessing such as noise removal and distortion correction is performed on the image signals obtained for each of the light illuminations in the A direction and the B direction,
Brightness data in the XX line direction as shown in the lower part of FIG. 2 and the lower part of FIG. 3 are prepared in pixel units in the width direction of the component image Ip (FIG.
Step ST5). In the illustrated example, the preprocessing is performed after two imagings, but the preprocessing may be performed for each imaging.

Incidentally, the brightness data of the A direction illumination shown in the lower part of FIG. 2 shows that the electrode area GIpd and the exterior area GIpj have almost the same brightness, the low brightness portion GIpl is provided at the left position corresponding to the shadow, and the color is formed. The high luminance portions GIph are respectively provided at the right positions corresponding to the portions. The brightness data of the B-direction illumination shown in the lower part of FIG. 3 indicates that the electrode region GIpd and the exterior region GIpj have almost the same brightness, a low-luminance portion GIpl is located at the right side corresponding to the shadow, and the color-forming portion is equivalent. The high-luminance portions GIph are respectively provided at the left positions. In the brightness data on the drawing, the low brightness portion GIpl and the high brightness portion GI
Although ph rises or falls sharply, the rise and fall of each actual part are gradual.

Next, the luminance values of the respective image data obtained by the A-direction illumination and the B-direction illumination are compared, and 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).

More specifically, starting from the center in the longitudinal direction of the component image Ip, a portion where a luminance difference occurs in the direction of the electrode portion in the other luminance data with reference to one luminance data is searched for, and the difference starts to appear mutually. This is defined as the edge position of the electrode portion. This edge detection is sequentially repeated while shifting the XX line in the width direction of the component image Ip in pixel units.

Next, the length from each of the edge positions to the end face of the component is determined 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 predetermined non-defective range, and the quality is determined, and the result is displayed on a CRT together with the input image. It is displayed (step ST8 in FIG. 4).

In this embodiment, by irradiating the inspection component P with light having an angle of about 60 degrees with respect to the imaging direction from each of the illuminators 2, the edge position of the electrode portion is positively shadowed at each imaging. In this case, even if the electrode portion and the exterior portion have the same light reflecting action, the edge position of the electrode portion is accurately detected from the image signal including the light and dark portions, and the dimensional inspection thereof is accurately performed. Can be done.

The edge potential of the electrode portion is detected by comparing the brightness values of the image signals obtained for each light irradiation in the A and B2 directions, and searching for a portion where the brightness difference appears depending on the presence or absence of a shadow or the like. Therefore, even when a low-luminance part or a high-luminance part exists in a part other than the edge on the luminance data, it is possible to prevent the erroneous detection of the low-luminance part or the high-luminance part as an edge and to improve the detection accuracy.

Further, by making the light irradiation directions A and B of each illuminator 2 perpendicular to the edge of the electrode portion, the edge position of the electrode portion is provided with clear light and dark along the edge, and the edge detection is easy. It is possible to obtain a proper image signal.

In the above-described embodiment, the inspection component having an exterior part is exemplified. However, it is a matter of course that the same dimensional inspection can be performed on a component having no exterior part and exposing the main body element.

In addition, although the inspection parts having the electrode parts at both ends of the parts have been exemplified, the parts having the electrode parts at positions other than both ends of the parts can also be inspected. In this case, an arrangement of the illuminator that produces a shadow at the edge position may be obtained.

Furthermore, the number of illuminators does not necessarily have to be two, but may be increased as appropriate according to the number of edges to be detected. In addition, a device that can separately irradiate light having different irradiation directions from one illuminator, for example, a device that can change the light irradiation direction by changing the angle of the reflector may be used.

As described above, in the embodiment, the present invention is applied to the dimensional inspection of the electrode part. However, the dimensional inspection of the inspected portion other than the electrode part, for example, the dimensional inspection of the exterior part or the inspection of the surface of the electronic component is performed. The present invention can be applied to the dimension inspection of the provided protrusions and recesses, and the same operation and effect can be obtained.

[0036]

As described above in detail, according to the first aspect of the present invention, at least two parts different from the imaging direction with respect to the inspection component are provided.
By irradiating light from the direction, the edge position of the inspected part is positively shaded at the time of each imaging, so that the inspected part and other parts have the same light reflection effect. Even in this case, it is possible to accurately detect the edge position of the inspected portion from the image signal including the light and dark and perform the dimensional inspection accurately.

According to the second aspect of the present invention, the luminance value of the image signal obtained for each light irradiation is compared, and a portion where the luminance difference mutually appears depending on the presence or absence of a shadow or the like is searched for, thereby detecting the edge potential of the inspected portion. Is detected, even when a low-luminance portion or a high-luminance portion exists in a portion other than the edge on the luminance data, it is possible to prevent the erroneous detection of the low-luminance portion or the high-luminance portion as an edge and to improve the detection accuracy. Other effects are the same as those of the first aspect.

According to the third aspect of the present invention, by making the light irradiation direction orthogonal to the edge of the inspected portion, the edge position of the inspected portion is provided with sharp contrast along the edge, and the edge detection is performed. An easy image signal can be obtained.
Other effects are the same as those of the first or second aspect.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a main part of a visual inspection apparatus to which the present invention is applied.

FIG. 2 is a diagram showing an input image and luminance data at the time of A-direction illumination.

FIG. 3 is a diagram showing an input image and luminance data during B-direction illumination.

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 visual inspection device.

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

FIG. 8 is a view showing luminance data when an electrode portion and other portions have the same light reflection effect.

[Explanation of symbols]

P: inspection part, Pd: electrode part, Pj: exterior part, 1: camera, 2: illuminator, Ip: part image, Ipd: electrode part of the part image, Ipj: exterior part of the part image, GIpd: luminance data Electrode area, GIpj: exterior area for luminance data, GIpl
... Low luminance part of luminance data, GIph... High luminance part of luminance data.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01B 11/00-11/30 102 G01N 21/84-21/958 G06T 1/00 G06T 7/00

Claims (3)

(57) [Claims] 1. An electronic component appearance inspection apparatus that detects an edge of an inspected portion of an electronic component, measures a dimension of the inspected portion based on the edge position, and determines whether the inspected portion is good or defective. Image input means, illuminating means capable of separately irradiating light to the inspection component from at least two directions forming an acute angle with the imaging direction, and performing image capturing by operating the image input means for each direction of light irradiation by the illuminating means. An appearance inspection apparatus for an electronic component, comprising: an imaging control unit; and an edge position detection unit that detects an edge position of an electrode unit based on an image signal obtained for each light irradiation. 2. The electronic component appearance inspection apparatus according to claim 1, wherein the edge position detection by the edge position detection means is performed by comparing luminance values of image signals obtained for each light irradiation. 3. The electronic component appearance inspection device according to claim 1, wherein a direction of light irradiation from the illumination unit is orthogonal to an edge of the inspection target portion.