JP2013032980A - Method for detecting missing parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for detecting missing parts capable of accurately detecting presence/absence of inspection objects on an inspection object surface such as whether or not an electronic component is mounted on a substrate.SOLUTION: A method for detecting missing parts inspects presence/absence of an inspection object 22 on an inspection object surface (an upper surface of a substrate 21) with luminance information captured by a camera 11. Either one of the surface of the inspection object 22 and the inspection object surface (the upper surface of the substrate 21) is configured to be a rugged surface 22b where reflected light 32 is less likely to enter the camera 11. Thereby, the presence/absence of the inspection object 22 produces a significant intensity difference in the luminance on an image captured by the camera 11.

Description

  The present invention relates to a shortage inspection method for automatically determining the presence or absence of an object to be inspected on a surface to be inspected, for example, the presence or absence of an electronic component on a substrate by a camera.

Conventionally, in an electronic circuit board manufacturing process, there is an inspection method using a camera as a method for inspecting whether or not an electronic component is mounted on a predetermined substrate.
There existed the thing of patent document 1 as this kind of conventional technology.
As shown in FIGS. 10 (a) and 10 (b), the substrate 104 (FIG. 10 (a)) on which the electronic component 103 is mounted and irradiated with the light from the light source 101 and the unmounted substrate 105 are mounted. Luminance information as shown in FIG. 10B is captured by the camera 102 and compared to inspect for missing parts of the electronic component 103.

Japanese Patent Laid-Open No. 06-201603

  However, in the above-described conventional technology, in the obtained luminance information, there is a small difference in luminance between the board 104 on which the electronic component 103 is mounted and the board 105 on which the electronic component 103 is not mounted.

  An object of the present invention is to provide a missing part inspection method capable of accurately inspecting the presence or absence of an object to be inspected on a surface to be inspected, such as whether or not an electronic component is mounted on a predetermined substrate.

In order to achieve the above object, the invention described in claim 1 is a shortage inspection method for inspecting the presence / absence of an object to be inspected on a surface to be inspected by luminance information captured by a camera, wherein the object to be inspected is provided. One of the surface and the surface to be inspected is in a surface state in which reflected light from the surface is difficult to enter the camera, and the other surface is reflected from the surface into the camera. It is characterized by an easy surface condition.
According to a second aspect of the present invention, in the shortage inspection method according to the first aspect, the surface of the object to be inspected is in a surface state in which reflected light from the surface hardly enters the camera. .
According to a third aspect of the present invention, in the shortage inspection method according to the first aspect, the surface to be inspected is in a surface state in which reflected light from the surface hardly enters the camera.
According to a fourth aspect of the present invention, in the shortage inspection method according to the first, second, or third aspect, the surface state in which the reflected light is less likely to enter the camera is an uneven surface.
According to a fifth aspect of the present invention, in the shortage inspection method according to any one of the first to fourth aspects, the object to be inspected is an electronic component.
According to a sixth aspect of the present invention, in the shortage inspection method according to any one of the first to fifth aspects, the surface to be inspected is an electronic circuit board surface.
According to a seventh aspect of the present invention, in the shortage inspection method according to the fifth or sixth aspect, the electronic component is an electronic circuit element.

  According to the present invention, there is a shortage inspection method for inspecting presence / absence of an object to be inspected on a surface to be inspected by luminance information captured by a camera, and the surface of the object to be inspected and the surface to be inspected are those surfaces Since the surface states are such that there is a great difference in the amount of reflected light between them, there is an effect that the presence or absence of the object to be inspected on the surface to be inspected can be accurately inspected.

It is explanatory drawing of the missing item inspection method which concerns on 1st Embodiment of this invention. It is a figure which shows the mode of the test | inspection at the time of the circuit element mounting in 1st Embodiment same as the above, (a) is a side view, (b) is a top view of a circuit board and a circuit element part. It is a figure which shows the mode of the test | inspection at the time of the circuit element non-mounting (at the time of a missing item) in 1st Embodiment same as the above, (a) is a side view, (b) is a top view of a circuit board part. It is explanatory drawing of the missing item inspection method which concerns on 2nd Embodiment of this invention. It is a figure which shows the mode of the test | inspection at the time of circuit element mounting in 2nd Embodiment same as the above, (a) is a side view, (b) is a top view of a circuit board and a circuit element part. It is a figure which shows the mode of the test | inspection at the time of the circuit element non-mounting (at the time of a missing item) in 2nd Embodiment same as the above, (a) is a side view, (b) is a top view of a circuit board part. It is principal part explanatory drawing of the missing item inspection method which concerns on 3rd Embodiment of this invention. It is principal part explanatory drawing of the missing item inspection method which concerns on 4th Embodiment of this invention. It is principal part explanatory drawing of the missing item inspection method which concerns on 5th Embodiment of this invention. It is explanatory drawing of a prior art, (a) is a figure which shows the time of electronic component mounting, (b) is the time of electronic component non-mounting (at the time of a missing item).

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol shows the same or an equivalent part between each figure.
FIG. 1 is an explanatory diagram of a missing item inspection method according to the first embodiment of the present invention.
In FIG. 1, reference numeral 11 denotes a camera such as a CCD camera, and reference numeral 12 denotes a light source composed of an LED or the like. The light source 12 is an annular light source in which a plurality of LEDs are arranged around the camera 11 in the illustrated example. However, the light source 12 is arranged by arranging a plurality of LEDs on a line in one to a plurality of rows. It may be 12. As long as the function as the light source 12 can be achieved, one LED may be arranged. A lamp other than an LED may be used as the light source 12.

1 shows an electronic circuit board (hereinafter abbreviated as a circuit board) 21 such as a printed circuit board, which is a surface to be inspected. (Hereinafter, abbreviated as a circuit element.) 22 shows a mounted state.
In the illustrated example, the circuit element 22 is mounted by soldering its terminal portion 22 a to a solder portion 21 b formed on the element mounting portion 21 a on the upper surface of the circuit board 21.
The camera 11 and the light source 12 are arranged on the upper side of the circuit board 21 so that the upper surface of the circuit board 21 including the mounting area of the circuit element 22 and the upper surface of the circuit element 22 to be mounted can be irradiated with light 31.
In the first embodiment, the upper surface of the circuit element 22 is a surface state in which the reflected light 32 (see FIG. 2A) of the light (incident light 31) from the light source 12 is difficult to enter the camera 11; It is set as the surface 22b. Note that the upper surface of the circuit board 21 remains a normal circuit board surface (flat surface), and is in a surface state in which the reflected light 32 of the light 31 from the light source 12 (see FIG. 3A) easily enters the camera 11. ing.

In the configuration shown in FIG. 1, when the light source 12 is turned on, the light 31 therefrom travels straight in the direction of the circuit board 21 (see FIGS. 1 and 2A).
Now, as shown in FIGS. 2A and 2B, when the circuit element 22 is mounted on the circuit board 21, the upper surface of the circuit element 22 is an uneven surface 22 b. Incident light 31 is irregularly reflected.
That is, the incident light 31 does not change its direction by 180 °, but reflects to the side as shown by the broken line in FIG. Therefore, the amount of reflected light 32 incident on the camera 11 is reduced, the amount of reflected light captured by the camera 11 is also reduced, and the brightness of the captured image is lowered.

On the other hand, as shown in FIGS. 3A and 3B, when the circuit element 22 is not mounted on the circuit board 21, the incident light 31 on the upper surface of the circuit element 22 is regularly reflected without being irregularly reflected.
That is, as indicated by a broken line in FIG. 3A, the incident light 31 is turned by approximately 180 ° to become reflected light 32, and the amount of the reflected light 32 incident on the camera 11 does not decrease so much. Therefore, the amount of reflected light captured by the camera 11 does not decrease so much, and the brightness of the captured image of the camera 11 is significantly higher than when the circuit element 22 is mounted on the circuit board 21 (see FIG. 2A). .

Therefore, whether the circuit element 22 is mounted on the circuit board 21 by measuring in advance the luminance of the captured image of the camera 11 when the circuit element 22 is mounted on the circuit board 21 and when the circuit element 22 is not mounted. It is possible to accurately check whether or not.
Specifically, the circuit element 22 is not mounted on the circuit board 21 if the brightness of the captured image of the camera 11 is extremely high, and the circuit element 22 is mounted on the circuit board 21 if the brightness of the captured image is low. It can be accurately inspected. Therefore, it is possible to easily realize high-precision inspection automation by setting a threshold value for the luminance value of the captured image.

FIG. 4 is an explanatory diagram of a missing item inspection method according to the second embodiment of the present invention.
In the second embodiment, the upper surface of the circuit element 22 remains a normal upper surface (flat surface) of the circuit element, and the surface on which the reflected light 32 of the light (incident light 31) from the light source 12 is likely to enter the camera 11. It is in a state. On the other hand, the mounting surface of the circuit element 22 on the upper surface of the circuit board 21 is a surface state in which the reflected light 32 of the light 31 from the light source 12 [see FIG. It is said that.

In the configuration shown in FIG. 4, when the light source 12 is turned on, the light 31 therefrom travels straight in the direction of the circuit board 21 (see FIGS. 4 and 5A).
As shown in FIGS. 5A and 5B, when the circuit element 22 is mounted on the circuit board 21, the upper surface of the circuit element 22 is flat. 31 reflects regularly without irregular reflection.
That is, as indicated by a broken line in FIG. 5A, the incident light 31 is turned by approximately 180 ° to become reflected light 32, and the amount of the reflected light 32 incident on the camera 11 does not decrease so much. Accordingly, the amount of reflected light captured by the camera 11 does not decrease so much, and the brightness of the captured image of the camera 11 is significantly higher than when the circuit element 22 is not mounted on the circuit board 21 (see FIG. 6A). .

On the other hand, as shown in FIGS. 6A and 6B, when the circuit element 22 is not mounted on the circuit board 21, the incident light 31 on the upper surface of the circuit board 21 is irregularly reflected.
That is, the incident light 31 does not change its direction by 180 °, but reflects to the side as shown by the broken line in FIG. Therefore, the amount of the reflected light 32 incident on the camera 11 is reduced, the amount of reflected light captured by the camera 11 is also reduced, and the brightness of the captured image of the camera 11 is obtained when the circuit element 22 is mounted on the circuit board 21 [ Compared to FIG. 5 (a)].

Therefore, whether the circuit element 22 is mounted on the circuit board 21 by measuring in advance the luminance of the captured image of the camera 11 when the circuit element 22 is mounted on the circuit board 21 and when the circuit element 22 is not mounted. It is possible to accurately check whether or not.
Specifically, the circuit element 22 is mounted on the circuit board 21 if the brightness of the captured image of the camera 11 is extremely high, and the circuit element 22 is not mounted on the circuit board 21 if the brightness of the captured image is low. It can be accurately inspected. Therefore, it is possible to easily realize high-precision inspection automation by setting a threshold value for the luminance value of the captured image.

  In both the first and second embodiments described above, the height from the upper surface of the circuit board 21 to the camera 11 and the light source 12 is inspected as shown in FIG. 2, FIG. 3 or FIG. On the other hand, if it is constant, a height difference corresponding to the height of the circuit element 22 occurs at the position of the reflection surface of the light from the light source 12 depending on the presence or absence of the circuit element 22 on the upper surface of the circuit board 21. However, the height dimension of the circuit board 21 with respect to the height dimension from the upper surface of the circuit board 21 to the camera 11 and the light source 12 is actually not as large as schematically shown in FIGS. Therefore, it is possible to cause a difference in the brightness of the captured image depending on the presence or absence of the circuit element 22 on the upper surface of the circuit board 21. Further, the height position of the camera 11 and the light source 12, the brightness of the light source 12, the form of the concave and convex surfaces 21c and 22b, and the like are adjusted and set so that the difference in height of the luminance becomes larger.

According to the first and second embodiments described above, the upper surface of the circuit element 22 or the circuit board 21 is the uneven surface 22b or 21c where the reflected light 32 of the light 31 from the light source 12 is difficult to enter the camera 11. On the other hand, the upper surface of the circuit board 21 or the circuit element 22 is a flat surface on which the reflected light 32 of the light 31 from the light source 12 easily enters the camera 11.
Therefore, the difference in brightness (brightness difference) of the captured image of the camera 11 can be increased, and thereby whether or not the circuit element 22 is mounted on the circuit board 21 can be accurately inspected. This also makes it possible to easily realize highly accurate inspection automation.
In particular, according to the first and second embodiments, the circuit element 22 (color 31 light-receiving surface) of the color circuit element 22 that has been difficult to inspect for a shortage by the conventional inspection using the camera 11 (image). ), Which has the great effect of being able to inspect missing items regardless of the color.

In the first embodiment described above, the concave and convex surface 22b of the circuit element 22 is configured to have a continuous isosceles triangle, but the present invention is not limited to this configuration. In short, as shown in FIG. 2A, the surface state may be such that the reflected light 32 of the light 31 from the light source 12 is difficult to enter the camera 11.
Therefore, for example, as shown in FIG. 7, the concave and convex surface 22b of the circuit element 22 may have a configuration in which right-angled triangles are continuous, or the entire upper surface of the circuit element 22 is formed as one inclined surface 22c as shown in FIG. It may be formed.

Furthermore, as shown in FIG. 9, the concave / convex surface 22b of the circuit element 22 is the same as that of the first embodiment (FIG. 1), but the lower surface has a concave / convex surface 91a that just fits the concave / convex surface 22b. The adapter 91 having the flat surface 91b may be deposited on the uneven surface 22b of the circuit element 22. In this case, the adapter 91 is formed of a light-transmitting synthetic resin such as a transparent epoxy resin, and an adhesive for attaching the adapter 91 onto the uneven surface 22b is also a light-transmitting adhesive. A material is used.
If such an adapter 91 is used, even if the circuit element 22 has the concavo-convex surface 22b, the circuit element 22 can be transported by the robot by vacuum-sucking the flat surface 91b of the adapter 91 before the main inspection. The circuit element (object to be inspected) 22 can be easily transported during surface mounting.
The shortage inspection method of the present invention can also be used when performing calibration at the time of equipment adjustment and periodic calibration using the principle.

  11: camera, 12: light source, 21: electronic circuit board (surface to be inspected), 21c, 22b: uneven surface, 22: electronic circuit element (object to be inspected), 31: light from light source (incident light), 32 :reflected light.

Claims (7)

A shortage inspection method for inspecting presence or absence of an inspection target object on a surface to be inspected by luminance information captured by a camera,
Of the surface of the object to be inspected and the surface to be inspected, either one of the surfaces is in a surface state in which reflected light from that surface is difficult to enter the camera, and the other surface is reflected from the surface. A missing item inspection method, wherein the surface state is easy to be incident on the camera.   2. The shortage inspection method according to claim 1, wherein the surface of the object to be inspected is in a surface state in which reflected light from the surface hardly enters the camera.   2. The missing item inspection method according to claim 1, wherein a surface to be inspected is in a surface state in which reflected light from the surface is difficult to enter the camera.   4. The missing item inspection method according to claim 1, wherein the surface state in which the reflected light is difficult to enter the camera is an uneven surface.   5. The shortage inspection method according to claim 1, wherein the object to be inspected is an electronic component.   6. The missing item inspection method according to claim 1, wherein the surface to be inspected is an electronic circuit board surface.   7. The shortage inspection method according to claim 5, wherein the electronic component is an electronic circuit element.

Images