JPH06201623A - Method and apparatus for inspecting defect at joint of different materials - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a method and device for detecting a defective joint portion of an inspection object with a simple configuration. [Structure] When inspecting whether or not there is a defective joint portion 7 on the joint surface 6 of the metal 3 and the metal 4 having poorer thermal conductivity than the metal 3,
The target site is heated from the metal 4 side by the high-intensity light source 10, the target site is imaged by the infrared imaging devices 1 and 2, and a temperature distribution image of the target site is obtained on the monitor 8. In the image of the monitor 8, a region 7a having a different temperature distribution from the other appears at the position corresponding to the defective bonding portion 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bonding failure inspection method and a bonding failure inspection apparatus for nondestructively detecting a bonding failure portion of an inspection object to which different materials are bonded.

[0002]

2. Description of the Related Art Conventional non-destructive inspection methods include ultrasonic flaw detection, magnetic flaw detection and radiation transmission. Of these, the radiation transmission method is mainly used to accurately detect a defective joint. The radiation transmission method irradiates the inspection object with radiation of uniform intensity and utilizes the difference in radiation absorption caused by the defective joint or structure of the object,
It is a method of recording the change in the transmitted dose on a film placed behind the object and examining the defective joint portion of the object to be inspected.

[0003]

Such a radiation transmission method requires radiation damage prevention equipment to use radiation during inspection. Since each cross section is recorded on a film, a large amount of film and a time required for the inspection are necessary for inspecting the joint failure portion of the inspection object in detail, and in some cases, The situation of missing inspection may occur.

Therefore, the present invention has been made to solve the above-mentioned problems of the prior art, and provides a method and apparatus for detecting a defective joint portion of an inspection object with a simple structure.

[0005]

According to the present invention, an object to be inspected is heated by a heat source, and by utilizing the difference in thermal conductivity of different materials, a defective bonding portion is detected by an infrared imaging device and displayed on a monitor. Is.

[0006]

The object to be inspected being heated by the heat source has a substantially uniform temperature distribution. Also, in the heat conduction process after heating,
The inspection object will have a uniform temperature distribution. However, if there is a defective joint in the inspection object, the heat conduction becomes poor at the defective joint, and the temperature distribution is not uniform.

By utilizing such a phenomenon, the present invention takes an image of infrared rays radiated from an object to be inspected after heating with an infrared imaging device and displays an infrared image on a monitor.
It is configured to detect the defective joint state of the inspection object from the image on the monitor.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the present invention. It is assumed that the inspection objects 3 to 7 have a defective joint portion 7 on the joint surface 6 of the metal 3 and the metal 4 having poorer thermal conductivity than the metal 3. When inspecting such inspection objects 3 to 7, if necessary, an infrared reflection preventing film 5 is provided on the inspection surface. As the infrared reflection preventing film 5, for example, a black body paint, a black body tape or the like can be used. A black body tape is a tape with a high emissivity film coated with an adhesive, and is used when it cannot be directly applied to the inspection target such as paint. The bonding failure inspection device has a high-intensity light source 10 that heats the inspection objects 3 to 7. Inspection object 3 to 7 heated by high-intensity light source 10
The surface of is imaged by the infrared imaging device body 1 and the imaging lens 2, and its temperature distribution is displayed on the monitor 8. When the inspection object 3 to 7 is heated by the light source 10, the metal 3
Has a better thermal conductivity than the metal 4, so that the heat of the metal 4 heated by the light source 10 is quickly conducted to the metal 3.
At this time, since the surfaces of the inspection objects 3 to 7 are heated almost uniformly by the light source 10, an image of the surface having a uniform temperature distribution appears on the monitor 8. After heating by the light source 10 for a predetermined time, the light source 10 is turned off. At this time, if the defective bonding portion 7 exists in the inspection objects 3 to 7, the heat conduction is deteriorated around the defective bonding portion 7 of the metal 4, and only the surrounding area has a temperature lower than that where the defective bonding portion 7 does not exist. Becomes higher and the temperature distribution is not uniform. Therefore, the inspection object 3 to 7 after heating
When infrared rays radiated from the infrared imaging device main body 1 and the lens 2 are imaged and an infrared image is displayed on the monitor 8,
A region corresponding to the defective joint portion 7 is displayed separately from the surroundings like a region 7a.

An observer can know that there is a defective joint 7 in the inspection objects 3 to 7 by the abnormality of the image displayed on the monitor 8 (the appearance of the area 7a). Bad joint 7
When there is not, since the surfaces of the inspection objects 3 to 7 are cooled with a uniform temperature distribution, no abnormality is found in the image displayed on the monitor 8. As described above, according to the above-described embodiment, the defective joint portion 7 of the inspection objects 3 to 7 can be detected with a simple configuration.

The light source 10 for heating the inspection objects 3 to 7 may be turned off after heating for a predetermined time as in the above embodiment, but after the inspection objects 3 to 7 are heated, the inspection is performed. You may keep away from the objects 3-7. The point is that the degree of heat radiation of the metal 4 is larger than the degree of heating of the metal 4, and the same applies even if the brightness of the light source 10 is reduced. Further, the light source 10 for heating can be replaced with another heat source, for example, a dryer.

Further, when the types of the inspection objects 3 to 7 are known in advance, the irradiation time of the light source 10 is controlled by a timer so that the inspection objects 3 to 7 can be heated to the minimum time. It can be set automatically.
Of course, since the distance between the inspection object 3 to 7 and the light source 10 is also a parameter, if the above-mentioned automatically set time is one, the light source 10 must be placed at a predetermined distance from the inspection object 3 to 7. Although not required, the automatically set time may be changed according to the distance between the light source 10 and the inspection objects 3 to 7.

The display of the infrared image on the monitor 8 is
It can be represented by black and white light and shade corresponding to temperature, or by color corresponding to temperature. Since the observation by the monitor 8 is performed after the heating of the inspection objects 3 to 7 is finished and the heat radiation from the metal 4 to the metal 3 is started, a message to that effect is displayed on the monitor 8 when the heating is finished. It is preferable to display inside.

Further, in the above-described embodiments, the defective joint portion is detected by observing the image on the monitor 8. However, if the joint portion is detected by image processing the infrared image signal, the inspection can be performed. It can also be automated. At this time, the inspection objects 3 to 7 and the bonding failure inspection devices 1, 2, 10
By relatively and stepwise moving two and
It is also possible to two-dimensionally inspect the defective joint portions of the inspection objects 3 to 7. By detecting the position of the optical axis of the imaging lens 2 on the inspection object 3 to 7 by the step movement with the position detector (the absolute position of the member moving in the step can be monitored, or the reference of the drive system motor can be used). It is possible by monitoring the amount of rotation from the position), and a two-dimensional map of the defective bonding portion is created by associating the defective bonding portion found by image processing with the position of the optical axis at that time. You can

As is clear from the above description, in the embodiment of the present invention, it is necessary that the metal on the side of the bonding failure inspection device has poorer heat conduction than other metals (heat is hard to be transmitted). According to the present invention, if the condition related to the heat conduction is satisfied, the inspection object is not only the dissimilar metal but also the metal and the glass (the glass has a lower heat conduction than the metal, so that the glass has a bonding failure inspection device side). It is also applicable to metals and plastics.

[0015]

As described above, according to the present invention, the object to be inspected can be heated by the heat source, and the bonding defect can be detected by utilizing the difference in thermal conductivity of different materials. The inspection can be done easily and inexpensively in time.

[Brief description of drawings]

FIG. 1 shows an embodiment of the device according to the invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Infrared imaging device main body 2 Imaging lens 3 Metal A 4 Metal B 5 Infrared antireflection film 6 Bonding part 7 Bonding failure part 8 Monitor 10 Light intensity light source

Claims (2)

[Claims] 1. An infrared imaging device detects a defective joint by utilizing a difference in thermal conductivity of different materials by heating an inspection object to which different kinds of materials are joined from the side of a material having poor heat conduction. A bonding failure inspection method characterized by the above. 2. A heat source for heating an inspection object to which different kinds of materials are joined, an infrared imaging device for imaging the inspection object heated by the heat source, and an infrared image taken by the infrared imaging device is displayed. A bonding failure inspection apparatus, comprising: a monitor, wherein the bonding failure portion is displayed on the monitor by utilizing a difference in thermal conductivity between different materials of the inspection object.