JP2012127786A - Lighting system and flaw detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flaw detection device and a lighting system suppressing the lowering of peripheral light quantity even if using a photographic lens with short focal length.SOLUTION: A plurality of LEDs 20B including both the longitudinal ends of an LED array 21 are fixed at an angle facing the longitudinal central side, or the direction facing the optical axis direction of a photographic lens 16, and LEDs 20A including the longitudinal center of the LED array 21 face the photographic lens 16 as they are without forming an angle. Hence the optical axis of the LED 20 faces the optical center direction of the photographic lens 16 at the periphery of both the longitudinal ends of the LED array 21, the illumination light quantity can be secured across the entire visual field of a CCD camera 14 without any deficiency in the peripheral light quantity (in this case, illumination light quantity in both the width-directional ends of copper foil 50).

Description

  The present invention relates to an illumination device and a defect inspection device, and more particularly to a defect inspection device that inspects a surface of an inspection object having a long strip shape with reflected light and a reflective illumination device used therefor.

  Conventionally, in order to inspect the surface of a long strip product or material on the production line of a factory for the presence of an abnormality, the surface of the object to be inspected is irradiated with illumination light, and the reflected light due to the surface reflection of the object to be inspected There is a defect inspection apparatus that detects the presence / absence of an abnormality by performing image processing with a computer and analyzing image data obtained and captured by an imaging means such as a CCD camera.

  For example, in a chip size package (CSP) in which the outer dimensions of a semiconductor device are reduced to the outer dimensions of a semiconductor element, a conductive film such as a copper foil is formed on the surface of a substrate such as a polyimide substrate by vapor deposition or the like. For a long tape patterned by repeating a plurality of patterns such as CSP wiring, electrodes, beam leads, and through holes using a normal etching technique, a defect of a plurality of patterns formed on the tape There has been proposed a defect inspection apparatus that detects a certain pattern and can distinguish it from a pattern having no defect (see, for example, Patent Document 1).

  In the example of the above-mentioned patent document 1, the presence or absence of abnormality is detected by scanning and photographing on the tape with a CCD camera or the like. At this time, since the angle of view of the lens of the CCD camera becomes wider as the focal length is shorter (wide), the tape transport surface and the CCD camera can be arranged closer to each other, so that the entire apparatus can be miniaturized. .

Japanese Patent Laid-Open No. 11-013096

  However, when a directional light source such as an LED array is used as the light source for illuminating the tape at the time of photographing, the vicinity of the peripheral portion in the scanning width direction is sufficient because the irradiation angle of the LED is large with respect to the optical axis of the CCD camera. There was a possibility that the amount of light could not be secured and the amount of light was insufficient.

  Therefore, an object of the present invention is to provide a defect inspection device and an illumination device that suppress a decrease in peripheral light amount even when an imaging lens having a short focal length is used.

  The illuminating device according to claim 1 is an illuminating device which is combined with an imaging device including an imaging optical system and extends in a direction intersecting with an optical axis of the imaging optical system, and has a directional light source. The optical axes of a plurality of light sources arranged in a straight line and including both ends in the arrangement direction are directed to the center in the arrangement direction.

  In the above invention, the optical axis of the plurality of light sources including both ends in the arrangement direction (= longitudinal direction) of the illuminating device is directed to the center in the longitudinal direction, thereby suppressing a decrease in the amount of light at the field periphery of the imaging optical system. it can.

  The defect inspection apparatus according to claim 2 is a defect inspection apparatus for inspecting a long belt-shaped inspection object conveyed in a strip shape with the surface as a reflection surface, and conveys the surface of the inspection object to be conveyed 2. The illumination device according to claim 1, wherein the illumination unit illuminates the inspection object from the upstream side or the downstream side in the conveyance direction of the inspection object and reflects the reflection surface by the reflection surface. Analyzing the image picked up by the image pickup means, and detecting the presence or absence of abnormality of the surface of the object to be inspected.

  In the above invention, the light axes of a plurality of light sources including both ends in the longitudinal direction of the illumination device are directed toward the center in the longitudinal direction, so that the amount of light of the object to be inspected that illuminates both ends in the transport width direction and enters the imaging means Therefore, it is possible to suppress a decrease in the amount of light at the peripheral edge of the field of the captured image.

  ADVANTAGE OF THE INVENTION According to this invention, it can be set as the defect inspection apparatus and illuminating device which suppress the fall of a peripheral light quantity, even if it uses an imaging lens with a short focal distance.

It is a conceptual diagram which shows the defect inspection apparatus which concerns on 1st Embodiment of this invention. It is an expansion perspective view which shows a part of defect inspection apparatus which concerns on 1st Embodiment of this invention. It is a conceptual diagram which shows the structure of the illuminating device shown in FIG. It is a conceptual diagram which shows the structure of the illuminating device shown in FIG. It is a conceptual diagram which shows the processing method and jig | tool of LED which concern on this invention. It is a conceptual diagram which shows a part of defect inspection apparatus which concerns on 2nd Embodiment of this invention. It is a conceptual diagram which shows the structure of the illuminating device which concerns on 3rd Embodiment of this invention. It is a conceptual diagram which shows the conventional defect inspection apparatus. It is a conceptual diagram which shows the conventional defect inspection apparatus.

  Hereinafter, embodiments will be described and embodiments of the present invention will be described. Here, in the second and subsequent embodiments, the same components as those already described are denoted by the same reference numerals, and the description thereof is omitted.

<First Embodiment>
1 to 3 are a conceptual view and a perspective view showing a defect inspection apparatus according to a first embodiment of the present invention.

<Overall configuration>

  In the defect inspection apparatus of this embodiment, as an example, the surface of the copper foil 50, which is an inspection object formed by rolling a metal thin film such as copper into a tape-shaped metal foil, is imaged with a CCD camera and analyzed by an analysis means. Thus, it is detected whether there is an abnormality on the surface of the copper foil 50 that is the inspection object. The copper foil 50 is attached to a defect inspection apparatus as a copper foil roll wound into a long tape shape and formed into a roll shape.

  The defect inspection apparatus 10 according to the present embodiment mainly includes a supply side copper foil roll 52, a conveyance roller 48, a tension roller 46, a winding side copper foil roll 54, an illumination device 12, and an imaging unit. As a CCD camera 14, a computer 40 as defect detection means, and a control unit 42.

  As shown in FIG. 1, in the defect inspection apparatus 10, the copper foil 50 is drawn from the supply-side copper foil roll 52 by a transport roller 48 driven by a driving means such as a motor (not shown), and the pair of tension rollers 46. It is conveyed while maintaining a predetermined tension between them. The copper foil 50 is further transported by the winding-side transport roller 48 and wound on the winding-side copper foil roll 54.

  At this time, the supply-side copper foil roll 52 and the winding-side copper foil roll 54 are rotated by driving means such as a motor (not shown), and in order to prevent the conveyance speed by the conveyance roller 48 from being affected, Feeding / winding is performed while maintaining moderate slack so as not to be applied. This control may be detected by, for example, a change in the rotation axis position of the tension roller 46 or a roller provided for tension detection.

  The copper foil 50 is conveyed between the tension rollers 46 at a predetermined speed and illuminated by the illumination device 12. As shown in FIGS. 2 and 3, the illuminating device 12 includes, for example, an LED array 21 in which LEDs 20 are arranged in a straight line, and irradiates the illuminating light to the copper foil 50 being conveyed in the direction of arrow S in the figure. The CCD camera 14 images the copper foil 50 at the position illuminated by the illumination device 12 and outputs the captured image to the computer 40 as an image signal.

  The computer 40 continues to detect whether the surface of the copper foil 50 is a uniform plane by processing the image signal output from the CCD camera 14. If there is an abnormality on the surface of the copper foil 50 (if it is determined by the computer 40 that the surface is not a uniform plane), the abnormality is detected and the copper foil 50 The movement amount (that is, the position of the copper foil 50 in the width direction and the movement amount of the copper foil 50 in the conveyance length direction) is calculated and output to the control unit 42.

  The control unit 42 records the position information of the part determined to be defective by the computer 40 as the position information of the abnormal part in a recording unit (not shown). Alternatively, when an abnormality is detected, a warning is given to the worker and a corresponding work is urged.

<Lighting device>
As shown in FIG. 3, the illumination light emitted from the illumination device 12 is reflected by the surface of the copper foil 50, picked up by the CCD camera 14, and the image is output to the computer 40 as an image signal. The CCD camera 14 includes a photographic lens 16 and a line CCD sensor 18.

  At this time, as shown in FIG. 3B, the light emitted from the illumination device 12 which is the LED array 21 from the upstream side in the transport direction of the copper foil 50 (the direction of arrow S in the figure) is the optical axis 20L in each LED 20. Has directionality in the direction.

  That is, as shown in FIGS. 3A and 3C, in the LED 20B at both ends in the length direction (conveying width direction of the copper foil 50) of the LED array 21 in which the LEDs 20 serving as light sources are linearly arranged, the optical axis 20LB, The LED 20A at the center in the length direction irradiates light in a direction along the optical axis 20LA. This is because a so-called bullet-type LED has a condensing lens structure at the tip and converges the light beam, and directs the light beam to increase the illuminance of the object to be inspected (copper foil 50). .

  At this time, as shown in FIG. 4, the LED array 21 changes the angle of the LED 20 fixed to the spacer 24 and the substrate 26 between the longitudinal ends and the center, thereby changing the light emitted from the LED 20 of FIG. Thus, the configuration is such that it substantially matches the angle of view θ1 of the photographic lens 16.

  That is, the plurality of LEDs 20B including both ends of the LED array 21 in the longitudinal direction are fixed at an angle facing the center in the longitudinal direction, that is, a direction facing the optical axis direction of the photographing lens 16, and the LED 20A including the center in the longitudinal direction of the LED array 21 is left as it is. It faces the taking lens 16 without an angle. However, actually, as shown in FIG. 3B, the light emitted from the LED 20 is reflected by the surface of the copper foil 50 and received by the CCD camera 14 side.

  At this time, as shown in FIG. 4, the LED 20B is bent at a predetermined angle in the direction in which the leg 22 protruding from the spacer 24 and the substrate 26 faces the optical axis direction of the photographing lens 16, and the optical axis 20LB is also predetermined. It faces the longitudinal center at an angle. That is, since the leg 22 portion is bent halfway, the leading portion of the LED 20B is oriented in the direction in which the leg 22 is bent (= the direction facing the center in the longitudinal direction). Alternatively, instead of bending the leg 22, a hole provided in the spacer 24 and the substrate 26 into which the LED 20 is inserted may be provided in an oblique direction so that the optical axis 20LB of the inserted LED 20B faces the center in the longitudinal direction.

<Effect>
As shown in FIG. 8, in the conventional defect inspection apparatus, the photographic lens 116 combined with the line CCD sensor 118 has a sufficiently long focal length and a narrow angle of view θ101. Therefore, the optical axis 120L of the LED 120 used in the illumination apparatus is Even at both ends in the longitudinal direction, it does not deviate greatly from the direction of the photographing lens 116, and as a result, the amount of illumination light does not become insufficient at both ends in the width direction of the inspection object such as the copper foil 50.

  On the other hand, as shown in FIG. 9, when the photographing lens 117 having a shorter focal length than the photographing lens 116 is used for the purpose of downsizing the entire defect inspection apparatus, the dimensions of the whole apparatus in the optical axis direction of the photographing lens 117 are used. Can be reduced.

  However, since the photographic lens 117 has a larger angle of view θ102 than the photographic lens 116, the optical axis 120L of the LED 120 deviates from the direction of the photographic lens 117 at both ends in the width direction of the inspection object such as the copper foil 50. Depending on the nature, the amount of illumination light may be insufficient. Since a decrease in the amount of illumination light may cause an influence such as a decrease in detection accuracy, it is necessary to correct this.

  Therefore, in the present invention, as shown in FIG. 3 (A), the plurality of LEDs 20 including both ends in the longitudinal direction of the LED array 21 are arranged such that the optical axis is directed to the longitudinal center side (optical center side of the photographing lens 16). .

  As a result, even when a single-focus lens is used as the photographing lens 16 in the past, the optical axis of the LED 20 is directed toward the optical center of the photographing lens 16 in the vicinity of both ends of the LED array 21 in the longitudinal direction. The illumination light quantity can be secured over the entire visual field of the CCD camera 14 without the light quantity (in this case, the illumination light quantity at both ends in the width direction of the copper foil 50) being insufficient.

<LED processing>
FIG. 5 shows an example of a leg bending method of the LED 20 according to the present invention.

  As shown in FIGS. 5A to 5C, in order to bend the leg 22 at a predetermined angle so that the optical axis 20L of the LED 20 is in a predetermined direction, a dedicated tool such as a jig 30 is used instead of a visual measurement. It is desirable to use

  The jig 30 includes a base block 32, an angle block 34, a pressing plate 36, and a pressure bonding plate 38. A gap 31 is provided on the back side of the base block 32 (the side where the leg 22 of the LED 20 is located) so that the leg 22 of the LED 20 can be touched. The side of the angle block 34 that contacts the base block 32 is provided with a slope 34A, and the leg 22 of the LED 20 can be bent at a desired angle by bending the leg 22 along the slope 34A.

  First, as shown in FIG. 5A, the base block 32 and the angle block 34 are positioned by pins (not shown). This may be configured to be screwed with screws 33. At this time, the base block 32 and the angle block 34 are not in close contact with each other, and there is a gap enough to sandwich the leg 22 of the LED 20.

  Next, the LED 20 is inserted into the gap between the base block 32 and the angle block 34, and the head of the LED 20 is pressed by the pressing plate 36 and positioned. At this time, as shown in FIG. 5B, working efficiency is improved by processing a plurality of LEDs 20 simultaneously.

  Further, the leg 22 of the LED 20 is bent along the slope 34 </ b> A of the angle block 34. Finally, the crimping plate 38 is fastened to the angle block 34 with screws 39. When the angle block 34 and the pressing plate 36 are removed and the LED 20 is taken out, the leg 22 is bent at an angle of the inclined surface 34A, that is, θ2 in FIG.

  At this time, by providing the vertical portion 34B on the slope 34A, it is possible to secure the vertical portion 22B protruding straight from the head of the LED 20 at the base of the leg 22. The length of the vertical portion 22B can be appropriately adjusted according to the thickness of the spacer 24 and the substrate 26 for fixing the LED 20.

Second Embodiment
FIG. 6 is a conceptual diagram showing a part of a defect inspection apparatus according to the second embodiment of the present invention.

  As shown in FIG. 6, instead of covering the entire conveyance width direction of the copper foil 50 as the inspection object with one CCD camera 14, a plurality of CCD cameras 14 so that the imaging ranges overlap in the width direction. And the surface of the copper foil 50 may be inspected as a whole.

  That is, since it is not necessary for the imaging range of the CCD camera 14 to be large enough to cover the width of the object to be inspected, it is possible to use a small size for the line CCD sensor 18 and the imaging lens 16, thereby reducing the component cost. can do.

  Similarly, when the size of the object to be inspected is large, by arranging a plurality of CCD cameras 14 so as to cover the entire width, it is not necessary to prepare a new large CCD camera. It is possible to flexibly cope with the change of the size of the inspection object.

<Third Embodiment>
FIG. 7 is a conceptual diagram showing a part of a lighting apparatus according to the third embodiment of the present invention.

  As shown in FIG. 7, the lighting device according to the present embodiment bends the both ends in the longitudinal direction so that the substrate 26 or the spacer 24 constituting the LED array 21 forms a concave surface with respect to the CCD camera 14. The shaft 20L is directed in the direction of the CCD camera 14.

  As a result, the same effect as that obtained by bending the legs 22 of the LEDs 20B at both ends in the longitudinal direction and directing the optical axis 20LB in the direction of the CCD camera 14 can be obtained. The amount of illumination light can be ensured over the entire field of view of the CCD camera 14.

  At this time, since the direction of the optical axis 20L of the LED 20 is determined according to the curved surface shape of the substrate 26 or the spacer 24 constituting the LED array 21, the optical axis 20L of the LED 20 changes stepwise depending on the longitudinal position of the LED array 21. Finer control of the optical axis direction is possible.

  Further, when the material of the substrate 26 or the spacer 24 constituting the LED array 21 is made flexible or plastic and is replaced with a photographing lens 16 having a different focal length, the substrate 26 or the spacer 24 is adjusted in accordance with the angle of view θ. It is good also as a structure which changes the shape.

  The embodiments of the present invention have been described above with reference to the embodiments. However, these embodiments are merely examples, and various modifications can be made without departing from the scope of the invention.

  For example, the present invention relates to a defect inspection apparatus for inspecting the surface of a long belt-like copper foil. However, the present invention is not limited to this. For example, the surface of any other metal may be mirror-finished. Various applications such as detection of abnormalities in small fixed objects such as screws conveyed on a long belt can also be considered for products made of these composite materials. Further, the illumination device alone can be applied to general uses such as close-up and copying where the illumination light quantity is required to be uniform.

DESCRIPTION OF SYMBOLS 10 Defect inspection apparatus 12 Illumination apparatus 14 Camera 16 Shooting lens 18 Sensor 20L Optical axis 21 LED array 22 Leg 22B Vertical part 24 Spacer 26 Substrate 30 Jig 40 Computer 50 Copper foil θ Field angle

Claims (2)

An illumination device combined with an imaging device including an imaging optical system and extending in a direction intersecting with the optical axis of the imaging optical system,
An illumination device, wherein light sources having directivity are arranged in a straight line, and optical axes of a plurality of light sources including both ends in the arrangement direction are directed to the center in the arrangement direction. A defect inspection apparatus for inspecting a long belt-shaped inspection object conveyed in a band shape with the surface as a reflection surface,
Imaging means for imaging the surface of the object to be transported across the transport width direction;
The illumination device according to claim 1, wherein the inspection object is illuminated over the conveyance width direction from the upstream side or the downstream side in the conveyance direction of the inspection object and reflected by the reflection surface;
Analyzing the image picked up by the image pickup means, and detecting the presence or absence of abnormality of the surface of the inspection object;
Defect inspection device with

Images