JPH072964U - Optical circuit defect inspection system - Google Patents

Abstract

(57) [Abstract] [Purpose] Highly accurate inspection of the partial thickness change and surface condition of the copper foil that constitutes the circuit of the printed wiring board. [Structure] A halogen optical ring light 2 and an illuminating halogen lamp 6 are arranged vertically and obliquely upward with respect to a printed wiring board 7 to be inspected. Further, on the front side of the halogen light ring light 2 and the halogen lamp 6 for illumination, a first polarizing filter 3 for vertical illumination having polarization directions different by 90 ° and a second polarizing filter 3 for illumination obliquely upward are provided. Polarizing filters 5 are installed respectively. A camera polarization filter 4 is provided in front of the first polarization filter 3, and a color CCD camera 1 is provided behind the halogen light ringlight 2.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an optical circuit defect inspection apparatus for inspecting a circuit defect of a printed wiring board.

[0002]

[Prior art]

 The following devices have been conventionally known as circuit defect inspection devices for printed wiring boards. One of them is to irradiate the printed wiring board to be inspected with light from the vertical direction and from diagonally above at the same time, and the specular reflection and the diffuse reflection are simultaneously captured from the vertical direction by one camera. In the second method, the fluorescence emitted by the fluorescent substance that has been mixed in the substrate of the printed wiring board in advance is captured by the camera.

[0003]

[Problems to be solved by the device]

 However, in the above two methods, for example, the thickness of the copper foil forming the circuit of the printed wiring board is reduced by several tens of μm due to physical or chemical reasons, and the shape on the plane is not changed. In this case, it was difficult to capture the change in thickness as an image from the direction perpendicular to the plate surface. Also, it was difficult to capture the minute surface condition of copper foil such as rust and uneven polishing.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an optical circuit defect capable of accurately inspecting even a minute defect in a circuit of a printed wiring board. To provide an inspection device.

[0005]

[Means for Solving the Problems]

 In order to achieve the above object, the optical circuit defect inspection apparatus according to the present invention is provided with a first light source and a second light source which are respectively arranged in a vertical direction and an obliquely upward direction of a printed wiring board to be inspected. And a first polarizing filter and a second polarizing filter which are arranged in front of the first and second light sources and have different polarization directions, and a camera provided in front of the first polarizing filter. A polarizing CCD and a color CCD camera for forming an image on the circuit surface by the reflected light reflected by the circuit surface of the printed wiring board, transmitted through the camera polarizing filter, and separated by the camera polarizing filter. It is characterized by the following configuration.

[0006]

[Action]

 By capturing the image of the circuit surface by the illumination light from the vertical direction and the diagonally upward direction of the printed wiring board separately into the color CCD camera, the copper foil that constitutes the circuit is three-dimensionally captured, and the minute thickness of the circuit is captured. Inspect for circuit defects by carefully grasping changes in the surface and surface conditions.

[0007]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory view of a circuit defect inspection apparatus for a printed wiring board according to the present invention, in which a circuit 8 is formed of copper foil on a printed wiring board 7.

A halogen light ring light 2 is provided as a first light source in a direction perpendicular to the circuit surface of the printed wiring board 7. Further, a halogen lamp 6 is provided as a second light source in an obliquely upward direction of 20 ° with respect to the circuit surface of the printed wiring board 7.

A first polarization filter 3 for illumination is provided in the front side of the halogen light ring light 2 in the vertical direction, and a camera filter 4 is provided in front of the first polarization filter 3. Further, on the rear side of the halogen light ring light 2, a color CCD camera 1 equipped with a polarizing lens is provided coaxially with the halogen light ring light 2.

On the other hand, on the front side of the halogen lamp 6, a second polarizing filter 5 for illumination is provided obliquely upward. The first polarization filter 3 and the second polarization filter 5 are arranged so that their phases differ by 90 °.

The present embodiment has such a configuration, and the circuit defect inspection is performed as follows. The light emitted toward the front surface of the printed wiring board 7 by the halogen light ringlight 2 and the halogen lamp 6 is the first polarization filter 3 for vertical illumination and the second polarization filter for diagonally upward illumination. It passes through the filter 5 and hits the circuit 8 of the printed wiring board 7 to be reflected. The reflected light passes through the camera polarization filter 4 and enters the color CCD camera 1.

The color CCD camera 1 images reflected light from the circuit surface while rotating the polarizing lens. That is, the color CCD camera 1 receives the two lights from the halogen light ringlight 2 and the halogen lamp 6 that have passed through the polarizing filter 4 for the camera, and forms an image on the circuit surface of the printed wiring board 7. The circuit image of the printed wiring board 7 obtained here is converted into a signal by the color CCD camera 1 and sent to an image processing circuit (not shown).

In the image processing circuit, the two images input from the color CCD camera 1 are compared, and the brightness distribution of the circuit image on the printed wiring board 7 is binarized based on each image signal. After that, a small change in the partial thickness of the copper foil forming the circuit and a change in the surface condition due to rust or the like are determined.

The inventors of the present invention compared the images in this way and inspected the circuit defects of the printed wiring board. As a result, the circuit defects thinned by about 10 μ were successfully detected. Furthermore, changes in the surface condition such as uneven polishing on the circuit surface could be detected in detail.

[0015]

[Effect of device]

 As described above, according to the present invention, it is possible to detect a minute change in the partial thickness of the copper foil forming the circuit of the printed wiring board, which was difficult to detect by the conventional inspection device.

Furthermore, changes in the surface condition of the copper foil can be captured more finely, enabling highly accurate inspection of circuit defects.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a circuit defect inspection apparatus for a printed wiring board according to the present invention.

[Explanation of symbols]

 1 Color CCD Camera 2 Halogen Light Ring Light 3 First Polarization Filter 4 Polarization Filter for Camera 5 Second Polarization Filter 6 Halogen Lamp for Lighting 7 Printed Wiring Board

Claims (1)

[Scope of utility model registration request] 1. A first light source and a second light source respectively arranged in a vertical direction and an obliquely upper direction of a printed wiring board to be inspected, and arranged in front of the first and second light sources. A first polarizing filter and a second polarizing filter having different polarization directions, a camera polarizing filter provided on the front side of the first polarizing filter, and a circuit surface of a printed wiring board, which is reflected by the camera. And a color CCD camera which forms an image of the circuit surface by the reflected light separated by the camera polarization filter and separated by the camera polarization filter.