JP3309420B2 - Inspection method of solder bridge - Google Patents

Inspection method of solder bridge

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Publication number
JP3309420B2
JP3309420B2 JP07668792A JP7668792A JP3309420B2 JP 3309420 B2 JP3309420 B2 JP 3309420B2 JP 07668792 A JP07668792 A JP 07668792A JP 7668792 A JP7668792 A JP 7668792A JP 3309420 B2 JP3309420 B2 JP 3309420B2
Authority
JP
Japan
Prior art keywords
image data
solder bridge
light
image
substrate
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
JP07668792A
Other languages
Japanese (ja)
Other versions
JPH05280946A (en
Inventor
暢史 戸倉
Original Assignee
松下電器産業株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 松下電器産業株式会社 filed Critical 松下電器産業株式会社
Priority to JP07668792A priority Critical patent/JP3309420B2/en
Publication of JPH05280946A publication Critical patent/JPH05280946A/en
Application granted granted Critical
Publication of JP3309420B2 publication Critical patent/JP3309420B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting a solder bridge , and more particularly, to a silk-printed portion which becomes noise in image data when inspecting the appearance of solder for bonding an electronic component to a substrate. And an inspection method of the solder bridge capable of removing the data of the above.

[0002]

2. Description of the Related Art After bonding electronic components such as ICs, LSIs, resistor chips, and capacitor chips to a substrate, the appearance of solder is inspected. Next, a method of inspecting the presence or absence of a solder bridge by a camera will be described.

In FIG. 7, reference numeral 4 denotes a substrate to be inspected, on which a circuit pattern 23 is formed. The circuit pattern 23 is formed by applying a solder plating on a copper foil and has a mirror surface. Substrate 4
Are formed by silk printing a frame 24a indicating the mounting position of the electronic component and characters 24b such as "IC5" indicating the type of the electronic component. FIG. 8 shows that after the electronic component 20 is mounted in the frame 24a, the leads 21 of the electronic component 20 are mounted.
9 shows a state in which the appearance inspection of the solder 22 that adheres to the circuit pattern 23 is performed.

In FIG. 1, reference numeral 1 denotes a camera for observing the substrate 4 from above, and 2 denotes a ring-shaped light source for irradiating illumination light. FIG.
Indicates an image captured by the camera 1. In the figure, 2
Reference numeral 6 denotes a solder bridge, which is generated by eluting the solder 22 to the side when the solder 22 is heated and cured. Since the solder bridge 26 short-circuits the leads 21, those having the solder bridge 26 are selected as defective substrates.
The silk printing unit 24 such as the frame body 24a and the character 24b includes:
It is formed of a light-colored paint such as white so that an operator can clearly identify it with the naked eye. The solder bridge 26 is also made of a bright metal. Accordingly, when observed by the camera 1, the frame 24a and the solder bridge 26 are observed brightly in a dark background as shown in the figure.

[0005]

The presence or absence of the solder bridge 26 is determined by performing optical scanning in the direction of the arrow between the leads 21 and determining whether or not there is a bright part. However, since the frame 24a shines brightly like the solder bridge 26, there is a problem that the frame 24a is erroneously recognized as the solder bridge 26.

Such a problem also occurs in cases other than the inspection for the presence or absence of a solder bridge. That is, for example, the substrate 4
In the case where an upper area is optically scanned and a bright and shining circuit pattern 23 is used as a guide to set an inspection area for a solder appearance inspection or the like by the camera 1, the bright and shining silk printed portion 24 is mistaken for the circuit pattern 23. However, the inspection area may be set at an incorrect position.

As described above, the board is observed by the camera,
When various optical inspections are performed based on the luminance distribution, the silk printed portion 24 shines brightly like the solder bridge 26 and the circuit pattern 23, so that image noise is generated and an erroneous inspection occurs. In order to solve such a problem, the silk-printed portion may be formed with a dark paint having a low luminance.
Printing with a dark paint causes a problem that it becomes difficult for an operator to visually recognize the print.

Accordingly, an object of the present invention is to provide a means for removing a silk-printed portion which becomes a noise from image data when observing a substrate with a camera and obtaining necessary image data.

[0009]

For this purpose, a method for inspecting a solder bridge according to the present invention is a method for observing a board in which leads of electronic components are soldered to a circuit pattern, wherein the first light source is perpendicular to the board. Irradiating illumination light and observing with a camera, and storing image data including light reflected at a silk printed portion between the leads and light reflected at a central portion of the solder bridge in a first image memory; and Illuminating the substrate with light from obliquely above the substrate and observing it with a camera, and stores image data including light reflected on the silk printed portion between the leads and light reflected on the inclined surface of the solder bridge in the second image memory. And performing an inter-image operation of the image data stored in the first image memory and the second image memory by the inter-image operation unit to remove the image of the silk printing unit,
A step of leaving an image of the solder bridge including the light reflected by the central portion and the inclined portion of the solder bridge, and optically scanning an inspection area set between the leads to determine the presence or absence of the solder bridge. Determining by the CPU.

[0010]

According to the above arrangement, the light irradiation angle is switched to irradiate the substrate with the irradiation light, and the image data captured by the camera is stored in the first image memory and the second image memory. The image data is computed by the computing unit to obtain image data from which noise by the printing unit has been removed.

[0011]

Next, an embodiment of the present invention will be described with reference to the drawings. First, the principle of the present invention will be described with reference to FIGS. FIG. 5 is an overall view of a substrate observation apparatus. The substrate 4 is provided with a silk-printed portion A and a metallic inspection object B having the same mirror property as the circuit pattern and the solder. The silk printed portion A and the inspection object B are inspection models for explaining the principle of the present invention, and the silk printed portion A is formed inside the inspection object B.

The optical system includes a camera 1 for observing a substrate 4 from above, and two ring-shaped light sources 2 and 3. The first light source 2 irradiates the substrate 4 with illumination light vertically or substantially vertically from above. The second light source 3 is larger than the first light source 2 and irradiates the substrate 4 with illumination light from obliquely above. By switching on and off the light sources 2 and 3 as described later, the irradiation angle of the illumination light is switched. First
The light source 2 emits light at an angle as steep as possible and desirably perpendicularly to the inspection area in the field of view of the camera 1 on the substrate 4. Therefore, a ring-shaped light source or a surface light source is used as the first light source 2. The second light source 3 uniformly irradiates the inspection area of the substrate 4 with light from the side. Therefore, a ring-shaped light source is used as the second light source 3. It should be noted that only one light source may be provided, and the light irradiation angle may be changed by moving the light source up and down. The means for switching the irradiation angle is not limited to this embodiment.

The camera 1 is connected to a first image memory 11 and a second image memory 12. The first image memory 11 stores image data M1 when the substrate 4 is irradiated with light from the first light source 2. Also, the second image memory 1
Reference numeral 2 stores image data M2 when the substrate 4 is irradiated with light from the second light source 3. An inter-image operation unit 13 combines image data M1 and image data M2,
The calculated image data M3 is stored in the third image memory 14. A CPU 15 performs various controls and calculations.

The inspection object B has a mirror surface. Therefore, the light a vertically emitted from the first light source 2 is reflected right above, enters the camera 1, and is observed brightly by the camera 1. The silk-printed portion A is printed with a light-colored material such as white paint, and the light b vertically emitted from the first light source 2 is irregularly reflected right above, enters the camera 1, and is observed brightly by the camera 1. Is done. The light c irradiated on the substrate 4
Is absorbed by the substrate 4, and the substrate 4 is observed dark. FIG.
In (a), M1 is the first light source 2 as described above.
Are image data captured by the camera 1 by irradiating illumination light vertically from the camera, and this image data is stored in the first image memory 11. As shown in the figure, the silk printed portion A and the inspection object B are observed brightly in a dark background indicated by a shadow line, and the silk printed portion A becomes noise and cannot be distinguished from the inspection object B.

In FIG. 5, when the second light source 3 is turned on, the light d illuminating the inspection object B from obliquely above is reflected obliquely upward and does not enter the camera 1, so that the camera 1 is observed darkly. Is done. In addition, the light e applied to the silk printing portion A
Is randomly emitted, enters the camera 1 and is observed brightly.
The light f applied to the substrate 4 is absorbed by the substrate 4 and is observed dark. In FIG. 6B, M2 is the image data in this case, and is stored in the second image memory 12. These image data M1, M2, M3 are "0",
This is binary data of "1", and "0" and "1" are described in the figure.

In FIG. 6C, M3 is image data obtained by subtracting the image data M2 from the image data M1 and stored in the third image memory 14. This subtraction is performed by the inter-image calculation unit 13. As shown in the figure, the silk printed portion A has “1” − “1” = “0”, and the inspection object B has “1” − “0” = “1”. Therefore, the inspection target B and the silk-printed portion A are clearly identified as “1” and “0”, and the silk-printed portion A does not become noise of the inspection target B.

Next, a method for inspecting a solder bridge utilizing the above principle will be described with reference to FIGS. This substrate 4 is the same as the substrate 4 shown in FIG. 8, and a description thereof will be omitted. The silk print portion 24a corresponds to the silk print portion A in FIG. 5, and the solder 22 and the solder bridge 26 correspond to the inspection object B.

Also in this case, similarly to the case described with reference to FIGS. 5 and 6, the first light source 2 irradiates the illumination light vertically and observes it with the camera 1, and the image data M1 is stored in the image memory. 11 is stored. Further, the second light source 3 is turned on, the illumination light is emitted from obliquely above and observed by the camera 1, and the image data M2 is stored in the image memory 12. FIG.
(A), (b) and (c) show the respective image data M1 and M
2 and image data M3 calculated by the inter-image calculation unit 13. In the figure, Q is the inspection area of the camera 1,
It is set between the leads 21.

FIG. 3 shows the reflection characteristics when illumination light is emitted vertically from the first light source 2. As shown in the figure, the upper surface of the solder bridge 26 has an inner concave shape, and a central portion 26a
Is reflected right above and enters the camera 1,
Although it is observed brightly, the light b incident on the inclined surface at the side is reflected obliquely upward and does not enter the camera 1, so it is observed darkly. Further, as described with reference to FIG. 5, the silk printed portion 24a reflects light right above and is observed brightly. Therefore, the image data M1 of FIG. 2 is obtained. As shown in the image data M1, only the central portion 26a of the solder bridge 26 is observed brightly.

FIG. 4 shows a reflection characteristic when the second light source 3 irradiates illumination light from obliquely above. The cross-sectional shape of the solder bridge 26 is mountain-shaped, so that the light c incident on the right side surface is reflected right above and enters the camera 1,
Although the light d is observed brightly, the light d incident on the upper surface is reflected obliquely upward and does not enter the camera 1, so that the light d is observed dark. The silk print portion 24a diffusely reflects light and is observed brightly. Therefore, the image data M2 of FIG. 2 is obtained. As shown in the image data M2, only the right side surface 26b of the solder bridge 26 is observed brightly in an arc shape. In the figure,
“1” and “0” are binarized values.

Therefore, the same operation as that shown in FIG. 6 is performed by the inter-image calculation unit 13, so that the image data M3 in FIG. 2 is obtained. From the image data M3, the image data of the silk print portion 24a, which is noise for determining the presence or absence of the solder bridge 26, is removed, and only the image data of the solder bridge 26 remains. The presence or absence of the solder bridge 26 is determined by the CPU 15 by optical scanning.

The present invention is not limited to the above-described embodiment. In short, in order to remove from the inspection area the image data of the silk-printed portion, which becomes noise, the capture of the image by the camera and the calculation by the inter-image calculation unit are performed. It should be done.

[0023]

According to the present invention as described in the foregoing, thus it has a bright luminance characteristic to remove the image data silk printing unit comprising a noise of the optical inspection, optical inspection of the presence or absence of a solder bridge It can be carried out.

[Brief description of the drawings]

FIG. 1 is an overall view of a substrate observation apparatus according to the present invention.

FIG. 2 is an image data diagram according to the present invention.

FIG. 3 is a side view showing light reflection characteristics according to the present invention.

FIG. 4 is a side view showing light reflection characteristics according to the present invention.

FIG. 5 is an overall view of a substrate observation apparatus according to the present invention.

FIG. 6 is an image data diagram according to the present invention.

FIG. 7 is a plan view of a conventional substrate.

FIG. 8 is a front view of a conventional substrate observation apparatus.

FIG. 9 is a conventional image data diagram.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Camera 2 1st light source 3 2nd light source 4 Substrate 11 1st image memory 12 2nd image memory 14 Inter-image calculation part 24 Silk printing part

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. 7 , DB name) G01B 11/24 G01N 21/88 G06T 7/00

Claims (1)

(57) [Claims]
1. A method of observing a substrate in which electronic component leads are soldered to a circuit pattern, wherein the substrate is illuminated with illumination light perpendicularly from a first light source, observed with a camera, and silk printed between the leads. Storing image data including the light reflected by the portion and the light reflected by the central portion of the solder bridge in the first image memory; Storing image data including light reflected by the silk-printed portion between the leads and light reflected by the inclined surface of the solder bridge in the second image memory; to remove the image of the silk printing unit performs the inter-image calculation of image data stored in said second image memory, the solder
A step of leaving an image of the solder bridge including the light reflected by the central portion of the bridge and the inclined portion, and optically scanning an inspection area set between the leads to determine the presence or absence of the solder bridge by the CPU. Determining a solder bridge.
JP07668792A 1992-03-31 1992-03-31 Inspection method of solder bridge Expired - Fee Related JP3309420B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP07668792A JP3309420B2 (en) 1992-03-31 1992-03-31 Inspection method of solder bridge

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP07668792A JP3309420B2 (en) 1992-03-31 1992-03-31 Inspection method of solder bridge

Publications (2)

Publication Number Publication Date
JPH05280946A JPH05280946A (en) 1993-10-29
JP3309420B2 true JP3309420B2 (en) 2002-07-29

Family

ID=13612371

Family Applications (1)

Application Number Title Priority Date Filing Date
JP07668792A Expired - Fee Related JP3309420B2 (en) 1992-03-31 1992-03-31 Inspection method of solder bridge

Country Status (1)

Country Link
JP (1) JP3309420B2 (en)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06311307A (en) * 1993-04-22 1994-11-04 Minolta Camera Co Ltd Image forming device
JP3104152B2 (en) * 1994-01-14 2000-10-30 アイ・ピー・アイ株式会社 Soldering condition inspection method and device
JP2775411B2 (en) * 1995-07-25 1998-07-16 名古屋電機工業株式会社 Lighting equipment for printed wiring board inspection equipment
JP4684033B2 (en) * 2005-07-12 2011-05-18 シーケーディ株式会社 Board inspection equipment
JP4969664B2 (en) * 2010-03-03 2012-07-04 シーケーディ株式会社 Solder printing inspection apparatus and solder printing system
JP6211798B2 (en) * 2013-05-17 2017-10-11 富士機械製造株式会社 Foreign matter inspection method and foreign matter inspection apparatus on substrate
JP6389651B2 (en) * 2013-09-10 2018-09-12 Juki株式会社 Inspection method, mounting method, and mounting apparatus

Also Published As

Publication number Publication date
JPH05280946A (en) 1993-10-29

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