KR101211438B1

KR101211438B1 - Apparatus for inspecting defects

Info

Publication number: KR101211438B1
Application number: KR1020100076935A
Authority: KR
Inventors: 이제선; 김경덕; 김종우; 이종식; 최백영
Original assignee: 주식회사 쓰리비 시스템
Priority date: 2010-08-10
Filing date: 2010-08-10
Publication date: 2012-12-12
Also published as: WO2012020932A3; KR20120014765A; WO2012020932A2

Abstract

The present invention relates to a defect inspection apparatus, comprising: collimating a pair of lights respectively to irradiate the inspection position of an inspection object, and a first overlapping region formed by overlapping edge portions of the pair of lights to be irradiated to the inspection position; Optical unit; A second optical unit for collimating a pair of lights to irradiate the inspection position, and irradiating overlapping regions formed by overlapping edge portions of the pair of lights to the inspection position; A control unit which controls the first optical unit and the second optical unit to light up alternately; And a camera for capturing an image of the inspection position by using light emitted from the first optical unit or the second optical unit and reflected from the inspection position.

Description

Fault Inspector {APPARATUS FOR INSPECTING DEFECTS}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defect inspection apparatus, and more particularly, to a defect inspection apparatus for inspecting a defect by irradiating an edge of a pair of light to the inspection object to overlap.

Defects in copper clad laminates, substrates in flat panel displays, films used for industrial materials, wire rods / steel plates, etc. have been thoroughly inspected for defects in finished products. As a method for inspecting these defects, light was irradiated to the inspection object and the light reflected or transmitted from the inspection object was imaged, and it was determined as a defect when the brightness of the image to be captured exceeds or falls short of the reference value.

However, when the inspection object is a steel product such as a plate or a wire, the reflectance on the surface is high, so it reacts sensitively to the difference of minute lighting conditions, which makes it difficult to accurately inspect the defects.

In particular, when the inspection object is a wire rod, the surface of the wire rod is curved and bright on some surfaces and dark on other surfaces, making it difficult to determine surface defects in photographed images. Difficulties in setting the field of view and focus had limitations in obtaining a clear image, which made it difficult to accurately inspect surface defects.

Accordingly, an object of the present invention is to solve such a conventional problem, and the edge of a pair of light is irradiated to overlap the inspection object, and such overlapping light is irradiated alternately in both directions of the inspection object to cause defects on the inspection object. By acquiring a clear image of the, to provide a defect inspection apparatus that can easily detect a defect on the inspection object.

In order to achieve the above object, the defect inspection apparatus of the present invention collimates a pair of lights to irradiate the inspection position of the inspection object, and the overlapping region formed by overlapping edge portions of the pair of lights is the inspection position. A first optical unit to irradiate the light; A second optical unit for collimating a pair of lights to irradiate the inspection position, and irradiating overlapping regions formed by overlapping edge portions of the pair of lights to the inspection position; A control unit which controls the first optical unit and the second optical unit to light up alternately; And a camera configured to capture an image of the inspection position by using light emitted from the first optical unit or the second optical unit and reflected from the inspection position and incident. Each of the optical units may further include an aperture in which a through hole through which the light passes is narrowed from the center portion toward the left and right directions.

A defect inspection apparatus according to the present invention, Preferably, the third optical unit for irradiating light to the inspection position; And a retroreflective plate which is irradiated with light emitted from the third light unit at the inspection position, and retroreflects the incident light back to the inspection position in the same direction as the incident direction. An image of the inspection position is captured by further using light that is retroreflected and reflected by the inspection position.

In the defect inspection apparatus according to the present invention, preferably, each of the first light unit and the second light unit comprises a pair of light sources, a condenser lens for condensing light emitted from the light source, and an optical axis of And a collimating lens spaced apart from the optical axis of the light source and the condensing lens and collimating the light incident from the condensing lens to advance the light inclined with respect to the optical axis toward the inspection position.

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In the defect inspection apparatus according to the present invention, preferably, when the virtual line connecting the first optical unit and the second optical unit and the moving direction of the inspection object is not orthogonal to each other, In order to change the direction, the aperture is rotatable about an optical axis of the condenser lens.

In the defect inspection apparatus according to the present invention, preferably, the overlapping region of the cross section of the light which is disposed between the first and second light units and the inspection object and is irradiated from the first or second light unit. And a slit member having a pair of slits for passing a portion forming the portion and blocking a portion not forming the overlapping region.

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According to the defect inspection apparatus of the present invention, the shadow effect can be maximized by using the edge portion of the light as inspection illumination.

In addition, according to the defect inspection apparatus of the present invention, the light using the retroreflective plate can also be utilized while alternately irradiating the light in both directions of the inspection object, thereby increasing the compatibility to cope with various inspection conditions.

Further, according to the defect inspection apparatus of the present invention, the diaphragm is rotatably installed, so that the image of the defect can be clearly obtained even if the position of the illumination is changed with respect to the advancing direction of the inspection object.

1 is a view showing a defect inspection apparatus according to an embodiment of the present invention.
FIG. 2 is a view showing an optical path in the first optical unit or the second optical unit of the defect inspection apparatus of FIG.
3 is a view showing various shapes of the aperture through-hole.
4 is a diagram illustrating a light amount distribution when light passing through an aperture overlaps;
5 is a view showing a state in which the aperture is rotated.

Hereinafter, embodiments of a defect inspection apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing a defect inspection apparatus according to an embodiment of the present invention, Figure 2 is a view showing the optical path in the first optical unit or the second optical unit of the defect inspection apparatus of Figure 1, Figure 3 FIG. 4 is a view illustrating various shapes of the aperture through hole, FIG. 4 is a view illustrating a light quantity distribution when light passing through the aperture overlaps, and FIG. 5 is a view illustrating a state in which the aperture is rotated.

1 to 5, the defect inspection apparatus 100 of the present embodiment may obtain a clear image of a defect by irradiating the inspection object so that the edge portions of the pair of lights overlap each other. 110, a second optical unit 120, a controller 130, a third optical unit 140, a retroreflective plate 150, a camera 160, and a slit member 170.

The first light unit 110 collimates a pair of light, respectively, and the edges overlap each other to irradiate the inspection position of the inspection object, a pair of light sources 111 and a pair of condenser lenses 112. ), A pair of collimating lenses 113, and a pair of apertures 114.

Referring to FIG. 2, in this embodiment, a high power LED light is used as the light source 111, and the light source 111 is coaxially disposed on the optical axis LA1 of the condensing lens 112 and from the light source 111. The irradiated light is collected by the condenser lens 112. On the downstream side of the condenser lens 112, a collimating lens 113 for collimating light passing through the condenser lens 112 is disposed. In this case, the optical axis LA2 of the collimating lens 113 is spaced apart from and parallel to the optical axis LA1 of the light source 111 and the condenser lens 112, so that the light passing through the condenser lens 112 is collimated lens. It is not incident symmetrically about the optical axis LA2 of 113, but is incident on one side of the collimating lens 113. The incident light proceeds inclined with respect to the optical axis LA2 of the collimating lens 113, and finally is irradiated to the inspection position IP of the inspection object 1.

A pair of light sources 111, a pair of condenser lenses 112, and a pair of collimating lenses 113 are arranged symmetrically with respect to the central axis CL shown in FIG. 2, thereby collimating lenses 113. Each light emitted from the beam toward the inspection position IP proceeds to be inclined in opposite directions with respect to the optical axis LA2 of the collimating lens 113, and the pair of lights 10 on the inspection position IP The overlapping area OR where the edge portions overlap each other is formed. That is, the overlapped area OR is irradiated to the inspection position IP.

In this embodiment, in order to maximize the shadow effect, the edge of the light is used as inspection illumination. On the other hand, despite the advantages of using the edge of the light described above, the edge of the light has a lower light intensity than the central portion. Therefore, as shown in FIG. 2, by overlapping the edge portions of the pair of lights 10 and causing the overlapping area OR to be irradiated to the inspection position IP, the intensity of the light intensity generated by using the edge portions of the light The degradation can be compensated for.

The diaphragm 114 is disposed in the optical path between the condenser lens 112 and the collimating lens 113, the through hole through which the light passes is formed such that the opening area becomes narrower from the center to the left and right directions. As shown in FIG. 3A, the through hole 114a may be formed in a trapezoidal shape, and as illustrated in FIG. 3B, the through hole 114b may be formed in an elliptic shape.

As described above, the through holes 114a and 114b are formed such that the openings become narrower from the center to the left and right directions, so that the amount of light in the region where the light does not overlap and the amount of light in the overlapping region OR where the pair of lights 10 overlap each other. This is to maintain the uniformity to some extent.

If the through hole has a constant opening area in the left and right directions, the light amount of the overlapped area OR in which the pair of lights 10 overlaps is considerably higher than the light amount in the region where the light does not overlap. However, as shown in FIG. 4, when the through-hole 114a is formed to have a narrower opening area from the center portion to the left-right direction, the area of the overlapped area OR, where the pair of lights 10 overlap, becomes smaller. The amount of light in the overlapped area OR may be maintained to be somewhat uniform with the amount of light in the area where the light does not overlap.

The second optical unit 120 collimates a pair of lights 10, respectively, and makes the edges overlap each other to irradiate the inspection position IP of the inspection object 1, and the first optical unit 110. Similarly, a pair of light sources 121, a pair of condenser lenses (not shown), a pair of collimating lenses (not shown), and a pair of apertures (not shown) are provided.

The light source 121, the condenser lens, the collimating lens, and the aperture of the second light unit 120 may include the light source 111, the condenser lens 112, the collimating lens 113, and the aperture of the first light unit 110. Since the configuration is the same as that of 114 and performs the same function, detailed description thereof will be omitted.

On the other hand, the diaphragm 114 is rotatably installed around the optical axis LA1 of the condenser lens 113.

As illustrated in FIG. 5, the first light does not cross the virtual line VL that virtually connects the first optical unit 110 and the second optical unit 120 and the inspection object 1 to be perpendicular to each other. The unit 110 and the second optical unit 120 may be disposed. In this case, by rotating the diaphragm 114 around the optical axis LA1 of the condenser lens 112 to change the direction of the light passing through the diaphragm 114, the overlapping area OR of the pair of lights 10 is reduced. It can be adjusted to be positioned on the virtual line VL. If the diaphragm 114 does not rotate, the pair of lights 10 passing through the diaphragm 114 having the through-hole 114a formed to narrow the area opened toward the left and right in the center portion do not overlap each other because the edge portions do not overlap each other. The problem that the area OR does not occur may occur.

The controller 130 controls the first optical unit 110 and the second optical unit 120 to alternately light up. When the first optical unit 110 is turned on by the control unit 130 and the second optical unit 120 is turned off, the pair of light 10 irradiated from the first optical unit 110 overlaps an edge portion thereof. When the first optical unit 110 is turned off by the control unit 130 and the second optical unit 120 is turned on by the inspection position IP, the pair of light irradiated from the second optical unit 120 is turned on. 10, the edge portions overlap each other and are irradiated to the inspection position IP.

The third optical unit 140 irradiates light to the inspection position IP. Referring to FIG. 1, a high power LED light is used as the light source 141 of the third light unit 130, and the light is reflected by the reflection mirror 142 and irradiated to the inspection position IP. The incident angle of the light of the third optical unit 140 is smaller than the incident angle of the light of the first optical unit 110 or the second optical unit 120.

The retroreflective plate 150 is a member that retroreflects incident light in the same direction as the incident direction. The light irradiated from the third light unit 140 is reflected at the inspection position IP of the inspection object 1 and is incident on the retroreflective plate 150, and the light incident on the retroreflective plate 150 is the same direction as the incident direction. Is reflected back to the inspection position IP.

The third optical unit 140 is always turned on while the first optical unit 110 and the second optical unit 120 are alternately turned on by the controller 130 according to the type of the inspection object 1 or the inspection conditions. You can keep it in the off state, or it can stay off all the time.

The camera 160 acquires a defect image on the inspection object 1 by capturing an image of the inspection position IP, and is disposed on an optical path of the third light unit 140. The retroreflected light from the retroreflective plate 150 is incident to the inspection object 1 side, and the light is reflected by the inspection object 1 and incident to the camera 160. In addition, the light irradiated from the first optical unit 110 or the second optical unit 120 is also incident to the inspection object 1 side, the light is reflected by the inspection object 1 and incident on the camera 160. By using the light retroreflected by the retroreflective plate 150, the light of the first optical unit 110, or the light of the second optical unit 120, an image at the inspection position IP of the inspection object 1 may be acquired. Can be.

A line scan camera or the like is generally used as the camera 160, and various image capturing means used in a defect inspection apparatus may be used.

The slit member 170 is to reduce the interference of light, and is disposed between the first and second light units 110 and 120 and the inspection object 1. Referring to FIG. 2, the slit member 170 is provided with a pair of slits 171. A portion 11 of the cross section of the light of the first optical unit 110 that forms the overlap region OR passes through the slit 171 and forms an overlap region OR of the cross section of the light of the first optical unit 110. The slit member 170 is disposed so that the portion 12 is not blocked by the slit 171.

Since the slit member disposed between the second optical unit 120 and the inspection object 1 is also configured in the same way and performs the same function, the detailed description thereof will be omitted.

Hereinafter, an embodiment of a defect inspection method using the defect inspection apparatus 100 according to the present invention configured as described above will be schematically described with reference to FIGS. 1 to 5.

The defect inspection method of this embodiment includes a first imaging step, a moving step, a first control step, a second imaging step, a moving step, a second control step, and a detection step.

In the first imaging step, the lighting state of the first optical unit 110 is maintained, and light is emitted from the first optical unit 110 and reflected at the inspection position IP to be incident on the camera 160. An image of a defect at the inspection position IP is picked up. In this case, the light irradiated from the first optical unit 110 is in the form of a pair of light 10 whose edge portions overlap each other, and the overlapping area OR is irradiated to the inspection position IP of the inspection object 1.

In the moving step, the inspection object 1 is moved by the vertical width of the scan line of the camera 160. A line scan camera is used as the camera 160 in this embodiment. The inspection object 1 is moved by the vertical width of the scan line of the line scan camera, and the image is captured by the camera 160 in the next scan line. Get ready to do

In the first control step, the first optical unit 110 is turned off through the control unit 130 and the second optical unit 120 is turned on.

In the second imaging step, the lighting state of the second light unit 120 is maintained, and the light irradiated from the second light unit 120 and reflected at the inspection position IP is incident on the camera 160. An image of a defect at the inspection position IP is picked up. In this case, the light irradiated from the second light unit 120 is in the form of a pair of light 10 whose edge portions overlap each other, and the overlapping area OR is irradiated to the inspection position IP of the inspection object 1.

In the moving step, the inspection object 1 is moved by the vertical width of the scan line of the camera 160, and the camera 160 prepares to capture an image in the next scan line.

In the second control step, the second optical unit 120 is turned off through the control unit 130 and the first optical unit 110 is turned on.

Thereafter, while repeatedly performing from the first imaging step to the second control step, an image is acquired through the first imaging step or the second imaging step. For example, an image is acquired through a first imaging step in a scan line of the camera 160, the inspection object 1 is moved by the vertical width of the scan line of the camera 160, and the next of the camera 160 Acquire an image through the second imaging step in the scan line, move the inspection object 1 by the vertical width of the scan line of the camera 160, and perform the first imaging step in the next scan line of the camera 160. Acquire an image. As described above, an image is obtained by alternately using the first imaging step and the second imaging step while advancing each scan line.

In the detecting step, the defects on the inspection object 1 are detected by sequentially merging the images acquired through the first imaging step or the images acquired through the second imaging step along the scan line of the camera 160. As a method of merging the images, the images acquired through the first imaging step and the images acquired through the second imaging step may be merged separately, or the images acquired through the first imaging step and the second imaging step. It is also possible to merge images at once while crossing the images acquired through.

Meanwhile, another embodiment of a defect inspection method using the defect inspection apparatus 100 according to the present invention will be described with reference to FIGS. 1 to 5.

The defect inspection method of this embodiment includes a first imaging step, a first control step, a second imaging step, a moving step, a second control step, and a detection step.

The first imaging step is to maintain the lighting state of the first optical unit 110, by using the light irradiated from the first optical unit 110 and reflected at the inspection position (IP) incident on the camera 160 An image of a defect at the inspection position IP is picked up. In this case, the light irradiated from the first optical unit 110 is in the form of a pair of light 10 whose edge portions overlap each other, and the overlapping area OR is irradiated to the inspection position IP of the inspection object 1.

In the moving step, the inspection object 1 is moved by the vertical width of the scan line of the camera 160. A line scan camera is used as the camera 160 of the present embodiment, and the inspection object 1 is moved by the vertical width of the scan line of the line scan camera, and the image is prepared for imaging in the next scan line.

Thereafter, while repeatedly performing from the first imaging step to the second control step, an image is acquired through the first imaging step or the second imaging step. For example, an image is acquired through a first imaging step in a scan line of the camera 160, and an image is acquired again through a second imaging step in the same scan line, and as long as the vertical width of the scan line of the camera 160 is obtained. The inspection object 1 is moved, an image is acquired through a first imaging step in the next scan line of the camera 160, and an image is acquired again through a second imaging step in the same scan line. As described above, an image is obtained by alternately using the first imaging step and the second imaging step for each scan line.

In the detecting step, the defects on the inspection object 1 are detected by merging the images acquired through the first imaging step and the second imaging step for each scan line of the camera 160. As a method of merging images, the images acquired through the first imaging step and the images acquired through the second imaging step are merged for each scan line of the camera 1, and the images are merged again over the entire scan line.

The scope of the present invention is not limited to the above-described embodiments and modifications, but can be implemented in various forms of embodiments within the scope of the appended claims. Without departing from the gist of the invention claimed in the claims, it is intended that any person skilled in the art to which the present invention pertains falls within the scope of the claims described in the present invention to various extents which can be modified.

100: defect inspection device 110: first optical unit
120: second optical unit 130: control unit
140: third optical unit 150: retroreflective plate
160: camera

Claims

A first optical unit for collimating a pair of lights to irradiate the inspection position of the inspection object, and an overlapping region formed by overlapping edge portions of the pair of lights to irradiate the inspection position;
A second optical unit for collimating a pair of lights to irradiate the inspection position, and irradiating overlapping regions formed by overlapping edge portions of the pair of lights to the inspection position;
A control unit which controls the first optical unit and the second optical unit to light up alternately; And
A camera for capturing an image of the inspection position by using the light irradiated from the first optical unit or the second optical unit and reflected from the inspection position and incident;
Each of the first optical unit and the second optical unit, the defect inspection apparatus further comprises an aperture formed such that the through-hole through which light passes from the center portion to the left and right direction becomes narrower.

The method of claim 1,
A third optical unit irradiating light to the inspection position;
And a retroreflective plate to which the light irradiated from the third light unit is reflected and incident at the inspection position, and retroreflects the incident light to the inspection position in the same direction as the incident direction.
The camera is defect inspection apparatus, characterized in that for imaging the image of the inspection position by further using the light that is retroreflected from the retroreflective plate and reflected from the inspection position.

The method of claim 1,
Each of the first optical unit and the second optical unit,
A pair of light sources, a condenser lens for condensing the light emitted from the light source, and an optical axis spaced apart from the optical axis of the light source and the condenser lens in parallel and collimating the light incident from the condensing lens to the inspection position The defect inspection apparatus further comprises a collimating lens for advancing light inclined with respect to the optical axis toward.

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The method of claim 3,
When the virtual line connecting the first optical unit and the second optical unit and the moving direction of the inspection object are not orthogonal to each other, the aperture stops the optical axis of the condensing lens to change the direction of the light passing through the aperture. Defect inspection apparatus, characterized in that rotatable around.

The method of claim 1,
Is disposed between the first and second light units and the inspection object, the portion of the cross section of the light irradiated from the first or second light unit to form the overlapping area passes and does not form the overlapping area. Part is a defect inspection apparatus further comprises; a slit member having a pair of slits to block.

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