JP2009085883A - Defect inspection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a defect inspection device capable of clearly capturing a scattered light image of a defect regardless of shape, size, kind, or the like of the defect. <P>SOLUTION: In this defect inspection device 1, a lens 2 supported on an inspection axis L is sequentially illuminated by reflection type dark-field illumination devices 5<SB>1</SB>-5<SB>4</SB>having LEDs 6<SB>1</SB>-6<SB>4</SB>for irradiating light at different irradiation angles to the lens 2 one by one, and is imaged by a camera 4. Similarly, the lens 2 supported on the inspection axis L is sequentially illuminated by transmission type dark-field illumination devices 7<SB>1</SB>-7<SB>3</SB>having LEDs 8<SB>1</SB>-8<SB>3</SB>for irradiating light at different irradiation angles to the lens 2 one by one, and is imaged by the camera 4. Thus, the irradiation angle of the light to the lens 2 is varied and the lens 2 is imaged, so that the scattered light image of the defect can be clearly captured regardless of the shape, size, kind, or the like of the defect. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a defect inspection apparatus for inspecting a defect of an inspection object.

As a conventional defect inspection apparatus, there is known an apparatus that sequentially irradiates light on a surface of an inspection object from a plurality of different irradiation directions and images or observes the surface of the inspection object at the time of light irradiation from each irradiation direction. (For example, see Patent Documents 1 and 2).
JP 2000-162146 A JP 2000-28476 A

  However, the conventional defect inspection apparatus as described above has a problem that the scattered light image of the defect cannot be clearly captured because the intensity of the scattered light becomes weak depending on the shape, size, type, and the like of the defect. .

  Therefore, the present invention has been made in view of such circumstances, and provides a defect inspection apparatus that can clearly capture a scattered light image of a defect regardless of the shape, size, type, and the like of the defect. For the purpose.

  In order to achieve the above object, a defect inspection apparatus according to the present invention is a defect inspection apparatus for inspecting a defect of an inspection object, the supporting means for supporting the inspection object on the inspection axis, and the support means An imaging means for imaging the object to be inspected supported by the plurality of first objects, and a plurality of first objects that are arranged so as to surround the inspection axis and irradiate the object to be inspected supported by the supporting means at a first irradiation angle. A plurality of second light irradiations for irradiating light at a second irradiation angle to a first illumination unit having a light irradiation unit and an object to be inspected that is arranged so as to surround the inspection axis and supported by the support unit A second illuminating means having a portion, wherein the illumination by the first illuminating means and the illumination by the second illuminating means are selectively performed.

  In this defect inspection apparatus, the inspection object supported on the inspection axis is provided by a first illumination unit having a plurality of first light irradiation units that irradiate the inspection object with light at a first irradiation angle. The image is picked up by the imaging means in a state of being illuminated or illuminated by a second illuminating means having a plurality of second light irradiating portions that irradiate the inspection object with light at a second irradiation angle. In this way, since the inspection object is imaged by changing the light irradiation angle to the inspection object, it is possible to clearly capture the scattered light image of the defect regardless of the shape, size, type, etc. of the defect. It becomes.

  In the defect inspection apparatus according to the present invention, it is preferable that the first illumination unit and the second illumination unit are arranged with a predetermined gap in the direction of the inspection axis and move in the direction of the inspection axis. In this case, the illumination state by the first illumination unit and the illumination state by the second illumination unit can be finely adjusted, and the scattered light image of the defect can be captured more clearly.

  In the defect inspection apparatus according to the present invention, the first and second illumination means are disposed on the imaging means side with respect to the inspection object, and the imaging means images the surface of the inspection object on the imaging means side. You may make it do. In this case, it is possible to capture a scattered light image of defects on the surface of the object to be imaged on the imaging means side by using the first and second illumination means as the reflection type dark field illumination means. Note that the reflection type dark field illumination means that when there is no defect on the surface of the object to be imaged on the image pickup means side, the light regularly reflected on the surface does not enter the image pickup means at an irradiation angle. Means illumination.

  In the defect inspection apparatus according to the present invention, the first and second illumination means are arranged on the opposite side of the imaging object with respect to the inspection object, and the imaging means images the surface and the inside of the inspection object. You may make it do. In this case, it is possible to capture a scattered light image of defects on the surface and inside of the inspection object by using the first and second illumination means as transmission type dark field illumination means. Note that transmissive dark field illumination irradiates the inspection object with light at an irradiation angle at which the light refracted by the inspection object does not enter the imaging means when there are no defects on the surface and inside of the inspection object. Means lighting.

  According to the present invention, a scattered light image of a defect can be clearly captured regardless of the shape, size, type, and the like of the defect.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing an embodiment of a defect inspection apparatus according to the present invention. As shown in FIG. 1, the defect inspection apparatus 1 is an apparatus for inspecting a defect of a lens (inspection object) 2. Defects include surface defects (for example, scratches, line flaws, dents, adhesion of foreign matter, etc.) and internal defects (for example, pinholes, internal bubbles, etc.).

  The defect inspection apparatus 1 includes a tray (support means) 3 that supports the lens 2 on the inspection axis L. The lens 2 is fitted in a through hole 3 a provided in the tray 3. The tray 3 can move in the X-axis and Y-axis directions perpendicular to the inspection axis L, and can rotate about the Z-axis parallel to the inspection axis L.

  On the inspection axis L, a camera (imaging means) 4 for imaging the lens 2 supported by the tray 3 is provided. The camera 4 is movable in the Z axis direction. A disc-shaped transmission type bright field illumination device 9 is provided at a position facing the camera 4 on the inspection axis L with the tray 3 interposed therebetween. The transmission type bright field illumination means that the inspection object is irradiated with light at an irradiation angle at which the light refracted by the inspection object is incident on the imaging means when there is no defect on the surface and inside of the inspection object. Means lighting.

Reflective dark field illumination devices (first and second illumination means) 5 _{1 to} 5 ₄ are arranged on the camera 4 side with respect to the tray 3. Each lighting device 5 ₁ to 5 ₄ are formed in an annular shape to surround the inspection axis L, and has a smaller diameter farther from the tray 3. Each lighting device 5 ₁ to 5 ₄ are arranged taking a predetermined gap from each other in the direction of the inspection axis L, and is movable in the Z-axis direction (i.e., the direction of the inspection axis L).

Each of the reflection type dark field illumination devices 5 _{1 to} 5 ₄ includes a plurality of LEDs (first and second light irradiation units) 6 _{1 to} 6 ₄ arranged in a matrix, and the LEDs 6 _{1 to} 6 _4. Irradiates the lens 2 supported by the tray 3 with light. Each LED 6 ₁ to 6 ₄ is the illumination apparatus ₅ 1 to 5 every _4, the angle of the irradiation angle (acute side formed between the inspection axis L and the optical axis of each LED 6 ₁ to 6 ₄ are with respect to the lens 2 supported by a tray 3 ) Is set to become smaller as the distance from the tray 3 increases. That is, each LED 6 ₁ to 6 ₄ is the illumination apparatus ₅ 1 to 5 every ₄ is irradiated with light at different irradiation angles with respect to the lens 2 supported by the tray 3.

Transmission-type dark field illumination devices (first and second illumination means) 7 _{1 to} 7 ₃ are arranged on the opposite side of the tray 3 from the camera 4. Each of the lighting devices 7 _{1 to} 7 ₃ is formed in an annular shape so as to surround the inspection axis L, and the diameter decreases as the distance from the tray 3 increases. Each of the lighting devices 7 _{1 to} 7 ₃ is arranged with a predetermined gap between each other in the direction of the inspection axis L, and is movable in the Z-axis direction (that is, the direction of the inspection axis L).

Each transmission type dark field illumination device 7 _{1 to} 7 ₃ is provided with a plurality of LEDs (first and second light irradiation units) 8 ₁ to 8 ₃ arranged in a matrix, and the LEDs 8 ₁ to 8 _3. Irradiates the lens 2 supported by the tray 3 with light. Each LED 8 ₁ to 8 _3, for each lighting device ₇ 1-7 _3, the angle of irradiation angle (inspection axis L and each LED 8 ₁ to 8 ₃ acute side formed by the optical axis to the lens 2 supported by a tray 3 ) Is set to become smaller as the distance from the tray 3 increases. In other words, the LEDs 8 ₁ to 8 ₃ irradiate light at different irradiation angles to the lens 2 supported by the tray 3 for each of the lighting devices 7 _{1 to} 7 ₃ .

The defect inspection apparatus 1 includes a control device 11 that controls the entire apparatus, and a display device 12 that displays an image captured by the camera 4, inspection results, and the like. The control device 11 moves the tray 3 in the X-axis and Y-axis directions and rotates around the Z-axis, moves the camera 4 in the Z-axis direction, and Z of each of the lighting devices 5 _{1 to} 5 ₄ and 7 _{1 to} 7 ₃ . Controls movement in the axial direction. The control device 11 controls so that illumination by the illumination devices ₅ 1 _{to 5 4,} 7 _1-7 3, 9 is selectively performed by one device. Further, the control device 11 performs the lighting of the lighting devices 5 _{1 to} 5 ₄ and 7 _{1 to} 7 _{3 so} that the LEDs 6 _{1 to} 6 ₄ and 8 ₁ to 8 ₃ are sequentially turned on in a predetermined number or all at the same time. To be controlled.

  The operation of the defect inspection apparatus 1 configured as described above will be described.

When inspecting a defect on the surface of the lens 2 on the camera 4 side, illumination by each of the reflection type dark field illumination devices 5 _{1 to} 5 ₄ is selectively performed one by one. At this time, the camera 4 is moved in the Z-axis direction while the tray 3 is moved in the X-axis and Y-axis directions and rotated around the Z-axis, so that the camera 2 is moved over the entire surface of the lens 2 on the camera 4 side. 4 is in focus. Thereby, the surface of the lens 2 on the camera 4 side is imaged by the camera 4, and if the lens 2 has a surface defect, the scattered light image of the surface defect is surely captured by the camera 4.

Incidentally, for high curvature surface of the lens 2, it is preferable to perform the illumination by reflective dark field illumination device 5 ₁ having LED 6 ₁ irradiation angle is greater with respect to the lens 2, with respect to low curvature surfaces of the lens 2 , it is preferable to perform the illumination by reflective dark field illumination device 5 ₄ with the irradiation angle is small LED 6 ₄ with respect to the lens 2. This is because reflection-type dark field illumination is performed on the surface of the lens 2 on the camera 4 side, so that only scattered light due to surface defects is incident on the camera 4.

On the other hand, when inspecting a defect on the surface and inside of the lens 2, illumination by each of the transmission type dark field illumination devices 7 _{1 to} 7 ₃ is selectively performed one by one. At this time, the camera 3 is moved in the Z-axis direction while the tray 3 is moved in the X-axis and Y-axis directions and rotated around the Z-axis, so that the surface of the lens 2 and the entire interior of the lens 4 are moved. Focus is adjusted. Thereby, the surface and the inside of the lens 2 are imaged by the camera 4, and if the surface defect or the internal defect exists in the lens 2, the scattered light image of the surface defect or the internal defect is surely captured by the camera 4. .

Incidentally, with respect to the lens 2 of the high NA, it is preferable to perform the illumination by transmission dark field illumination device ₇₁ having the LED 8 ₁ irradiation angle is greater with respect to the lens 2, with respect to the lens 2 of the low-NA, lens it is preferred to carry out the illumination by transmission dark field illumination device 7 ₃ with the irradiation angle is small LED 8 ₃ against 2. This is because transmissive dark field illumination is performed on the surface and the inside of the lens 2 so that only scattered light due to surface defects or internal defects is incident on the camera 4.

By the way, when there is unevenness on the surface of the object to be inspected, the lighting devices 5 _{1 to} 5 ₄ and 7 _{1 to} 7 ₃ turn on the LEDs 6 _{1 to} 6 ₄ and 8 ₁ to 8 ₃ with a predetermined number. It is preferable to carry out sequentially. This is because it is possible to prevent a predetermined portion from being shaded by the unevenness and reliably capture the scattered light image of the surface defect on the entire surface of the inspection object. Further, when inspecting a defect on the surface and inside of the lens 2, illumination by the transmissive bright field illumination device 9 may be performed. Further, a microscope arranged alternately with the camera 4 on the inspection axis L may be provided. In this case, after the position of the defect is specified by the camera 4, it is possible to inspect the shape, size, type, and the like of the defect with a microscope in more detail.

As described above, in the defect inspection apparatus 1, the lens 2 supported on the inspection axis L has the reflective dark field illumination having the LEDs 6 _{1 to} 6 ₄ that irradiate the lens 2 with light at different irradiation angles. The devices 5 _{1 to} 5 ₄ sequentially illuminate one device at a time and are imaged by the camera 4. Similarly, the lens 2 supported on the inspection axis L is one device at a time by the transmission type dark field illumination devices 7 _{1 to} 7 ₃ having LEDs 8 ₁ to 8 ₃ that irradiate the lens 2 with different irradiation angles. Illuminated sequentially and imaged by the camera 4. Thus, since the lens 2 is imaged by changing the light irradiation angle to the lens 2, it becomes possible to clearly capture the scattered light image of the defect regardless of the shape, size, type, etc. of the defect. .

In the defect inspection apparatus 1, the reflection type dark field illumination apparatuses 5 _{1 to} 5 ₄ are arranged with a predetermined gap from each other in the Z-axis direction, and are movable in the Z-axis direction. Similarly, the transmission type dark field illumination devices 7 _{1 to} 7 ₃ are arranged with a predetermined gap from each other in the Z-axis direction, and are movable in the Z-axis direction. Thereby, the illumination state by each illuminating device 5 _{1 to} 5 ₄ , 7 _{1 to} 7 ₃ can be finely adjusted, and the scattered light image of the defect can be captured more clearly.

  The present invention is not limited to the embodiment described above. For example, the object to be inspected is not limited to a lens, and the shape of the object to be inspected may be a stepped or flat shape, and the material of the object to be inspected may be a metal or the like. In this case, only surface defect inspection is possible in which the camera-side surface of the object to be inspected is imaged by the camera under illumination by the reflective dark field illumination device. Further, instead of moving the camera 4 in the Z-axis direction, a zoom mechanism may be adopted for the camera 4 to focus the camera 4 on the surface or inside of the lens 2.

It is a lineblock diagram showing one embodiment of a defect inspection device concerning the present invention.

Explanation of symbols

1 ... defect inspection apparatus, 2 ... lens (inspection object), 3 ... tray (support means), 4 ... camera (imaging _{means), 5} 1 to 5 4 _... reflective dark field illumination device (the first and second Illuminating means), 7 _{1 to} 7 ₃ ... Transmission type dark field illumination device (first and second illumination devices), 6 _{1 to} 6 ₄ , 8 ₁ to 8 ₃ ... LED (first and second light irradiation units) ), L: Inspection axis.

Claims (4)

A defect inspection apparatus for inspecting a defect of an inspection object,
A support means for supporting the object to be inspected on an inspection axis;
Imaging means for imaging the object to be inspected supported by the support means;
A first illuminating unit having a plurality of first light irradiation units arranged to surround the inspection axis and irradiating the inspection object supported by the support unit at a first irradiation angle; ,
A second illuminating unit having a plurality of second light irradiation units arranged to surround the inspection axis and irradiating the inspection object supported by the support unit at a second irradiation angle; With
The defect inspection apparatus, wherein illumination by the first illumination means and illumination by the second illumination means are selectively performed.   2. The defect according to claim 1, wherein the first illuminating means and the second illuminating means are arranged with a predetermined gap in the direction of the inspection axis and move in the direction of the inspection axis. Inspection device. The first and second illumination means are arranged on the imaging means side with respect to the inspection object,
The defect inspection apparatus according to claim 1, wherein the imaging unit images a surface of the inspection object on the imaging unit side. The first and second illumination means are disposed on the opposite side of the imaging means with respect to the inspection object,
3. The defect inspection apparatus according to claim 1, wherein the imaging unit images the surface and the inside of the inspection object.

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