JPH05288527A - Appearance inspecting method for mounted board and its device - Google Patents

Abstract

PURPOSE:To provide the appearance inspecting method of a mounted board and its device inspecting the shape of an inspection' section such as a soldered section and having improved detection precision. CONSTITUTION:A lighting means 4 having LEDs 6a-6d is formed into a dome shape so that the radiated light can be condensed at the solder fillet 3 section of an electronic component 2 on a printed board 1. The LEDs 6a-6d are arranged at every 90 deg. and individually lighted. Reflected light images of the fillet 3 section having multiple different radiation directions are photographed by a television camera 7. The reflected light images are changed in response to the radiation directions and the stereoscopic shape of the fillet 3, these images are individually image-processed to detect the orientation of the curved element of the fillet 3 section, and the processed information is integrated to judge the quality of the fillet 3 section.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting board appearance inspection method and apparatus for inspecting electronic components mounted on a printed circuit board for displacement, lead floating, solder defects and the like.

[0002]

2. Description of the Related Art FIG. 6 is an explanatory diagram showing an example of a conventional mounting board appearance inspection method capable of detecting three-dimensional shape information.

In FIG. 6, 1 is a printed circuit board, 2 is an electronic component, and 3 is a solder fillet when the electronic component 2 is mounted on the printed circuit board 1 by soldering. Reference numeral 101 is an imaging device.

Then, a slit light 102 is emitted from a laser light source (not shown), and a light cutting line 103 is distorted along the surface shape on the surfaces of the electronic component 2 including the solder fillet 3 and the printed circuit board 1. To generate. The reflected light image of the light cutting line 103 is picked up by the image pickup device 101, and the three-dimensional shape of the solder fillet 3 is detected by checking the distortion state of the picked-up pattern.

[0005]

However, in the above-mentioned conventional mounting board appearance inspection method, only the shape information of the portion irradiated with the slit light 102 can be obtained, and the three-dimensional shape of other portions can be grasped. It is difficult and the detection accuracy is poor.

The present invention solves such a conventional problem, and enables the shape of a portion to be inspected such as a soldering portion to be detected to improve the detection accuracy. It is an object of the present invention to provide a mounting board appearance inspection method and apparatus.

[0007]

A mounting board appearance inspection method of the present invention for achieving the above object illuminates an object to be inspected sequentially from a plurality of different directions, and combines the characteristics of an image obtained each time. The quality is judged to be good or bad.

A mounting board appearance inspection apparatus of the present invention for achieving the above object is a dome-shaped illuminating means divided into a plurality of directions, and the illuminating means is divided into a plurality of directions and sequentially turned on. Control means for switching the illumination direction, image pickup means for picking up an object to be inspected from the dome top of the dome-shaped lighting means, and means for processing the image picked up by this image pickup means to judge good or bad It is a thing.

[0009]

Therefore, according to the present invention, the surface of the inspected portion such as the soldering portion is sequentially irradiated with light of different directions,
By capturing the pattern of each reflected light image of the inspected part and detecting the orientation of the aspect elements of the inspected part, that is, the change according to the three-dimensional shape of the inspected part, the shape of the inspected part can be determined. Can be detected.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing a mounting board appearance inspection apparatus according to an embodiment of the present invention, FIG. 2 (a) is a sectional view showing the same inspection apparatus, and FIG. 2 (b) is a light source used in the same inspection apparatus. 5 is an explanatory view of the arrangement, FIG. 3 is an explanatory view of an image processing circuit used in the inspection apparatus, FIG. 4 is a side view showing a mounting state of electronic components, and FIG.
(A)-(d) is a top view of the detection image in each irradiation condition which shows the mounting board appearance inspection method in one Example of this invention.

1 and 2, 1 is a printed circuit board,
Reference numeral 2 is an electronic component (chip component), and 3 is a solder fillet when the electronic component 2 is mounted on the printed board 1 by soldering. The printed circuit board 1 etc. is a table (not shown)
And moves in the XY directions according to the inspection sequence. Reference numeral 4 denotes an illuminating means for illuminating an inspected portion from above in order to inspect a mounting state of the electronic component 2 on the printed circuit board 1, and a large number of light sources which are individually turned on every 90 degrees inside the dome-shaped frame 5. The LEDs (light emitting diodes) 6a to 6d are provided, and are arranged so that the emitted light can be condensed on the solder fillet 3 portion on the printed circuit board 1. Reference numeral 7 denotes a television camera which is arranged in the hole 8 at the top of the illumination means 4 and which images the portion to be inspected from above.

In FIG. 3, 9 is an image input unit, 10 is an image processing unit for processing an image captured by the television camera 7 and sent from the image input unit 9, and 11 is information sent from the image processing unit 10. A determination processing unit for determining the mounting state of the component 2, 12 is an illumination control unit, and the LED 6 of the illumination means 4
A, 6b, 6c and 6d are sequentially switched to light.

With the above structure, the appearance inspection method will be described below. While the LEDs 6a, 6b, 6c, 6d of the illumination means 4 are sequentially switched and turned on by the illumination control unit 12, the television camera 7 captures images of the solder fillet 3 which is the inspected site under each illumination condition, and the image input unit 9
After that, the image processing unit 10 performs image processing. At this time, the television camera 7 can capture the reflected light image of the solder fillet 3 part by the illumination of the LEDs 6a, 6b, 6c, and 6d in different irradiation directions.

In the detection image diagrams under the respective illumination conditions shown in FIGS. 4A to 4D, the solder fillet 3 shines brightly, and the portion e corresponding to white in the binarized image is indicated by diagonal lines and appears dark, and A portion f corresponding to black in the binarized image is shown in white. Then, as shown in FIG.
In the illumination by the ED 6a, the shape of the white part e of the binarized image becomes gradually narrower from the skirt to the top of the fillet 3. As shown in FIG. 4B, in the illumination by the LED 6b, the shape of the white part e of the binarized image becomes gradually wider from one side of the fillet 3 to the upper end. As shown in FIG. 4C, in the illumination by the LED 6c, the entire fillet 3 becomes the shadow of the electronic component 2 and becomes the black f of the binarized image. As shown in FIG. 4 (d), the LED
In the illumination by 6d, the shape of the white part e of the binarized image gradually widens from the hem part to the upper end part on the other side part of the fillet 3.

As described above, the shape, size, and position of the white portion e of the binarized image changes depending on the illumination direction of the LEDs 6a to 6d, and the shape of the solder fillet 3 also determines the characteristics of each fillet 3. Represent Therefore, the determination processing unit 11 comprehensively processes the processing information and determines whether the soldering fillet 3 is good or bad.

[0017]

As described above, according to the present invention, the surface of the inspected portion such as the soldering portion is sequentially irradiated with light in different directions, and the pattern of each reflected light image of the inspected portion is picked up, By detecting the orientation of the curved surface element of the inspected part, the three-dimensional shape of the inspected part can be detected. Therefore, the detection accuracy can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing a mounting board appearance inspection device according to an embodiment of the present invention.

FIG. 2A is a cross-sectional view showing a mounting board appearance inspection device according to an embodiment of the present invention, and FIG. 2B is a layout explanatory view of a light source used in the appearance inspection device.

FIG. 3 is a block diagram showing an image processing circuit used in a mounting board appearance inspection device according to an embodiment of the present invention.

FIG. 4A is a side view showing a mounting state of electronic components.

5A to 5D show a mounting board appearance inspection method according to an embodiment of the present invention, which is a plan view of a detection image under each illumination condition.

FIG. 6 is an explanatory view showing a conventional mounting board appearance inspection method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printed circuit board 2 Electronic component 3 Solder fillet 4 Illumination means 6 LED 7 Television camera 9 Image input section 10 Image processing section 11 Judgment processing section 12 Lighting control section

Claims (2)

[Claims] 1. An object to be inspected is sequentially illuminated from a plurality of different directions, and the characteristics of the image obtained in each case are comprehensive,
Mounting board appearance inspection method for determining defects. 2. A dome-shaped illuminating means divided into a plurality of directions, a control means for dividing the illuminating means into a plurality of directions and sequentially lighting them, and switching the illuminating direction, and the dome-like illuminating means. A mounting board appearance inspection device comprising: an image pickup unit that picks up an image of an object to be inspected from the top of a dome;