JP2000221144A - Foreign object inspecting device of transparent film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a foreign object inspecting device for accurately detecting a foreign object contained in a transparent film, even if the film is run at high speed. SOLUTION: In a device 1, a one-dimensional CCD camera 4 can travel on an annular path 3 in a running direction A of a transparent film 10, so that it passes an upstream measurement point 3b and a downstream measurement point 3c, and an upstream side camera detection sensor 5 for detecting the passage of the upstream measurement point 3b of the one-dimensional CCD camera 4 and a downstream side camera detection sensor 6 for detecting the passage of the downstream measurement point 3c of the one-dimensional CCD camera 4 are provided. Then, a quality-judging device 9 judges whether or not the transparent film 10 conforms by inspecting a foreign object in the transparent film 10, based on an image pick-up signal from the one-dimensional CCD camera 4 after the detection by the upstream side camera detection sensor 5 to the detection by the downstream side camera detection sensor 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent film foreign matter inspection apparatus for inspecting foreign matter contained in a transparent film by running the transparent film.

[0002]

2. Description of the Related Art Conventionally, as a transparent film foreign matter inspection apparatus, a running transparent film is scanned with a one-dimensional CCD camera or a laser beam to detect a change in the amount of light transmitted through the transparent film or diffused light, and thereby to detect a transparent film. 2. Description of the Related Art There is known an apparatus which inspects foreign substances in a film to determine the quality of the product. For example, in an inspection apparatus described in Japanese Patent Application Laid-Open No. 6-242023, a lighting device irradiates a transparent film running at a speed of several meters per minute from below, and has a predetermined resolution fixed above the transparent film. One-dimensional CCD
The camera detects the presence or absence of foreign matter contained in the transparent film by receiving the transmitted light of the transparent film and capturing an image.

[0003]

However, in such a conventional inspection apparatus, when the transparent film is run at a high speed of, for example, several tens of meters per minute in order to shorten the inspection time and increase the efficiency, the running time is reduced. There is a problem that the scanning speed of a one-dimensional CCD camera or a laser beam cannot catch up with the speed, making it difficult to detect a foreign substance. In particular, when the foreign matter is minute, it is difficult to find it, and there is a high possibility that a transparent film that should be originally determined to be defective is determined to be good.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a transparent film foreign matter inspection apparatus capable of detecting foreign matter contained in a transparent film with high accuracy even when the transparent film runs at high speed. The task is to provide.

[0005]

According to a first aspect of the present invention, there is provided a transparent film foreign matter inspection apparatus for illuminating a traveling transparent film with inspection light, and an illumination device for receiving the inspection light. An imaging device that images the transparent film, and a quality determination device that inspects foreign matter in the transparent film based on an imaging signal from the imaging device and determines the quality of the transparent film, wherein the imaging device is It is movable in the traveling direction on the line so as to pass through the first fixed point and the second fixed point on the line along the traveling direction of the transparent film in this order, and detects passage of the first fixed point of the imaging device. First detecting means for detecting the passing of the second fixed point of the imaging device, and the second determining means is configured to detect whether or not the image quality is good by the first detecting means. By Based on the imaging signal until there is detected, and performs inspection of the foreign substance.

According to this transparent film foreign matter inspection apparatus, since the image pickup device takes an image while moving in the running direction of the transparent film between the first fixed point and the second fixed point, the transparent film viewed from the image pickup device is taken. The running speed of the transparent film is reduced, and even if the running speed of the transparent film is absolutely high, the running speed viewed from the imaging device is not so high. For this reason, the imaging can follow the high-speed running of the transparent film, and the detection of foreign matter in the transparent film can be performed with high accuracy.

If the image pickup device is not located between the first fixed point and the second fixed point on the line, the pass / fail judgment device does not inspect foreign substances, and during this time, the image pickup device is performing a return operation and is not transparent. Even when the film is not ready to be imaged, it is possible to achieve efficient inspection and labor saving without performing useless inspection.

According to a second aspect of the present invention, there is provided a transparent film foreign matter inspection apparatus according to the first aspect of the present invention, which includes a section defined by the first fixed point and the second fixed point on the line. A road, a plurality of the imaging devices are provided on the annular road, and each of the imaging devices can be circulated in a fixed direction along the annular road so as to move in the traveling direction in the section. By continuously repeating the inspection of the foreign substance based on the imaging signal from each imaging device circulating along the road,
An overall inspection of the transparent film is performed.

According to this transparent film foreign matter inspection apparatus, a plurality of image pickup devices repeat image pickup while circulating along an annular road, so that a limited number of image pickup devices do not stop the running of the transparent film without stopping the running of the film. A full inspection can be performed.

In addition, the imaging device does not need to keep moving in the traveling direction forever in order to image a wide range at a time.
The size of the entire inspection apparatus can be reduced within a range in which an annular path can be secured.

[0011]

Embodiments of the present invention will be described with reference to the drawings.

FIGS. 1 and 2 show an apparatus for inspecting foreign matter in a transparent film according to the present invention. This transparent film foreign matter inspection device 1 includes an illumination device 2 and an annular rail 3 serving as an annular road.
A one-dimensional CCD camera 4 as an imaging device, an upstream camera detection sensor 5 as first detection means, a downstream camera detection sensor 6 as second detection means, and a control device 7
, An A / D conversion device 8, a pass / fail determination device 9, and a film feeding mechanism (not shown). This film feed mechanism causes the transparent film 10 to travel in the traveling direction A. The transparent film 10 is, for example, a protective film for a photomask used at the time of manufacturing a printed wiring board, and it does not matter whether it is colorless or transparent.

The illuminating device 2 incorporates a straight tube-type fluorescent lamp (not shown) and is installed below the running transparent film 10. The illuminating device 2 has an irradiating section 2 a on its upper surface, and irradiates the transparent film 10 with uniform inspection light.

The annular rail 3 has a section 3a forming a part thereof.
So that the transparent film 10 extends along the traveling direction A.
It is installed above. The section 3a is a portion of the annular rail 3 where both ends are separated by an upstream fixed point 3b as a first fixed point and a downstream fixed point 3c as a second fixed point, and the upstream fixed point 3b and the downstream fixed point 3c. Are located above the irradiation unit 2a of the lighting device 2. Further, the upstream camera detection sensor 5 and the downstream camera detection sensor 6 are installed so as to face the upstream fixed point 3b and the downstream fixed point 3c, respectively.

Six one-dimensional CCD cameras 4 are movably provided on the annular rail 3, and each one-dimensional CCD camera 4 circulates on the annular rail 3 while maintaining a predetermined installation interval under the control of the control device 7. This circulation direction is a direction indicated by an arrow B so as to coincide with the traveling direction A in the section 3a. In the section 3a, the one-dimensional CCD camera 4
Receives the inspection light transmitted through the transparent film 10 while moving in the traveling direction A, and images the transparent film 10. An imaging signal from the one-dimensional CCD camera 4 is sent to an A / D converter 8.

The A / D converter 8 is connected to an upstream camera detection sensor 5 and a downstream camera detection sensor 6. The upstream camera detection sensor 5 is a one-dimensional CCD camera 4
And the detection of A / D
It is sent to the converter 8 as an upstream detection signal. The downstream camera detection sensor 6 detects that the one-dimensional CCD camera 4 has passed through the downstream fixed point 3c, and sends this detection to the A / D converter 8 as a downstream detection signal.

The A / D converter 8 captures an image signal from the one-dimensional CCD camera 4 whose passage has been detected and converts it into an A / D signal only during the period from when the upstream detection signal is received to when the downstream detection signal is received. D-convert. The result of the A / D conversion is sent to the pass / fail determination device 9 and is subjected to inspection for foreign substances contained in the transparent film 10 to determine the pass / fail of the transparent film 10 as a product. More specifically, the amount of light received by pixels constituting each one-dimensional CCD camera 4 is sequentially detected along a horizontal direction (film width direction) C orthogonal to the running direction A, and the amount of received light is determined by the amount of foreign matter in the transparent film 10. When it is reduced by light shielding and falls below a preset quality determination reference value (FIG. 3), the transparent film 10 is determined to be defective. Here, since the plurality of one-dimensional CCD cameras 4 sequentially pass through the section 3a and the detection signals are issued by the respective camera detection sensors 5 and 6, the above-described foreign substance inspection is performed on the imaging signals from the respective one-dimensional CCD cameras 4. It is repeated.

In the inspection apparatus 1, assuming that the traveling speed of the transparent film 10 is Vs and the moving speed of the one-dimensional CCD camera 4 is Vc (<Vs), the transparent film 10 is moving in the section 3a. Speed (V
s-Vc). For this reason, as shown in order from top to bottom in FIG. 4, the imaging region (the hatched portion in the drawing) of the transparent film 10 by the one-dimensional CCD camera 4 gradually expands. In order to continuously inspect the entire area of the transparent film 10 so that the imaging areas of the one-dimensional CCD cameras 4 are continuously arranged so as not to overlap, the installation interval of the one-dimensional CCD cameras 4 is determined based on the following general consideration. Has been determined.

As shown in FIG. 5, the upstream fixed point 3b (A /
A fixed point 3c on the downstream side from the point at which the D / A converter 8 starts capturing an image signal, and the point at which the A / D converter 8 captures an image signal ends.
L1 and the installation interval of the one-dimensional CCD camera 4 is L2, and an arbitrary one-dimensional CCD camera 4 (hereinafter referred to as "one-dimensional CCD camera 4a" for convenience) is an upstream fixed point 3.
b at time t = 0, the one-dimensional CCD camera 4 following the one-dimensional CCD camera 4a (hereinafter referred to as “one-dimensional CC
D camera 4b ". ) Passes through the upstream fixed point 3b at t = t1, and the time at which the one-dimensional CCD camera 4a passes through the downstream fixed point 3c is t = t2 (> t1).

The one-dimensional CCD camera 4a, which has moved from the upstream fixed point 3b by the distance L2 at the time t1, thereafter has reached the downstream fixed point 3c before the one-dimensional CCD camera 4b of the transparent film 10 is reached. Must be imaged in a region of length L2, which has not been imaged yet. That is, the one-dimensional CCD camera 4a and the one-dimensional CCD camera 4b see the speed (Vs-V
The transparent film 10 traveling in c) is moved for a time (t2-t).
Since the image must be taken for the length L2 during 1), the following equation (1) holds.

L2 = (Vs−Vc) × (t2−t1) (1) On the other hand, from the definition, t2 = L1 / Vc (2) t1 = L2 / Vc (3) From the equations (1) to (3), L2 = {1− (Vc / Vs)} × L1 (4)

Hereinafter, more specific embodiments will be described.

The width of the transparent film 10 along the horizontal direction C is 200 mm, and the transparent film 10 is required to detect a foreign substance of at least about 50 μm. Regarding the specifications of the one-dimensional CCD camera 4, the number of elements in one line is 5000 bits, the operation clock (cycle for reading the signal of one element) is 20 MHz, and the field of view per camera is 25.
0 mm, and the resolution in the width direction is 0.05 mm / pixel.

Also, the traveling speed Vs of the transparent film 10 is 40 m / min, the moving speed Vc of the one-dimensional CCD camera 4 is 20 m / min, and the distance between the upstream fixed point 3b and the downstream fixed point 3c (= section 3a). If the length L1 is 200 mm, the installation interval L2 of the one-dimensional CCD camera 4 is 10
0 mm.

In the inspection apparatus 1 according to this embodiment, the one-dimensional CCD camera 4 moves the transparent film 1 in the section 3a.
Since the imaging is performed while moving in the traveling direction A of 0, the traveling speed of the transparent film 10 viewed from the one-dimensional CCD camera 4 is reduced by the traveling speed Vc, and the traveling speed Vs of the transparent film 10 is absolutely increased. However, the traveling speed (Vs-Vc) viewed from the one-dimensional CCD camera 4 is not so high. Therefore, the imaging can follow the high-speed traveling of the transparent film 10, and even if a small foreign matter is included in the transparent film 10, it can be detected with high accuracy.

For example, in the above embodiment, the one-dimensional C
The relative speed of the transparent film 10 viewed from the CD camera 4 (V
s-Vc) is 20 m per minute, and 1 of the transparent film 10
The traveling distance per second is {(20 × 10 ³ ) / 60} mm
Becomes The time required for one scan by the line sensor with the number of elements n and the operation clock C [MHz] is Δn /
Since it is generally expressed as (C × 10 ⁶ )｝ [sec], the resolution in the flow direction in the inspection apparatus 1, that is, the moving distance of the transparent film 10 per scan is {(20 × 10 ³ ) / 60} × ｛. 5000 / (20 × 1
0 ⁶ )｝ = 0.083 mm.

On the other hand, according to the conventional inspection apparatus in which the imaging device is fixed, the moving speed of the transparent film with respect to the one-dimensional CCD camera is 40 m / min under the same conditions as described above, so that the resolution in the flow direction is 0.1 mm. 167 mm. Therefore,
Inspection device 1 is about 50% of the resolution in the flow direction
Has been improved.

In this inspection apparatus 1, a one-dimensional CCD
When the camera 4 is not in the section 3a, the image signal is not taken into the A / D converter 8 and the pass / fail judgment device 9 does not inspect foreign substances. Even if the film 10 is not in the image pickup state, it is possible to achieve efficient inspection and labor saving without performing useless inspection.

Further, since a plurality of one-dimensional CCD cameras 4 repeat image pickup while circulating along the annular rail 3,
Even when the number of one-dimensional CCD cameras 4 is limited, the entire surface of the transparent film 10 can be imaged and inspected without stopping the traveling thereof, and the overall size of the inspection apparatus 1 can be reduced.

Although the specific embodiments of the present invention have been described with reference to the drawings, the present invention is not limited to the above-described configuration, and design changes and the like may be made without departing from the scope of the invention. Even if present, it is included in the present invention.

For example, in the inspection apparatus 1, six one-dimensional CCD cameras 4 are used. However, by increasing the number of the one-dimensional CCD cameras 4, the traveling speed of the transparent film can be increased while securing the imaging accuracy. Also, the one-dimensional CCD camera 4 is provided not on the fixed annular rail 3 but on a chain or the like that rotates along a conceptual annular path, and rotates and moves together with the chain or the like. Is also good.

[0032]

As described above, according to the transparent film foreign matter inspection apparatus according to the first aspect, the image pickup apparatus moves between the first fixed point and the second fixed point in the running direction of the transparent film and picks up the image. Is performed, the running speed of the transparent film as viewed from the imaging device is reduced, and even if the running speed of the transparent film is absolutely high, the running speed as viewed from the imaging device is not so high. For this reason, the imaging can follow the high-speed running of the transparent film, and the detection of foreign matter in the transparent film can be performed with high accuracy.

When the image pickup device is not located between the first fixed point and the second fixed point on the line, the pass / fail judgment device does not inspect the foreign matter, and during this time the image pickup device is performing the return operation and is not transparent. Even when the film is not ready to be imaged, it is possible to achieve efficient inspection and labor saving without performing useless inspection.

According to the second aspect of the present invention, since a plurality of imaging devices repeatedly perform imaging while circulating along the annular road, the running of the transparent film is stopped by a limited number of imaging devices. A full inspection of the film can be performed without the need.

Further, the imaging device does not need to keep moving in the running direction forever in order to image a wide range at a time.
The size of the entire inspection apparatus can be reduced within a range in which an annular path can be secured.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a foreign matter inspection device for a transparent film according to the present invention.

FIG. 2 is an explanatory diagram illustrating a schematic configuration of a transparent film foreign matter inspection device of FIG. 1;

FIG. 3 is an explanatory diagram showing a pass / fail judgment method based on an imaging result of a one-dimensional CCD camera.

FIG. 4 is an explanatory diagram showing a state in which an imaging area of a one-dimensional CCD camera is sequentially enlarged.

FIG. 5 is an explanatory diagram showing the image pickup by two consecutive one-dimensional CCD cameras with time.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Foreign-material inspection apparatus of a transparent film 2 Illumination apparatus 3 Annular rail (annular path) 3a Section 3b Upstream fixed point (1st fixed point) 3c Downstream fixed point (2nd fixed point) 4 One-dimensional CCD camera (imaging device) 5 Upstream camera Detection sensor (first detection means) 6 Downstream camera detection sensor (second detection means) 9 Pass / fail judgment device 10 Transparent film A Running direction

Claims (2)

[Claims] An illumination device for irradiating a traveling transparent film with inspection light, an imaging device for receiving the inspection light and imaging the transparent film, and an image pickup device for imaging the transparent film based on an imaging signal from the imaging device. And a quality judgment device for judging the quality of the transparent film, wherein the imaging device passes a first fixed point and a second fixed point on a line along the running direction of the transparent film in this order. A first detection unit configured to be movable in the traveling direction on the line, the first detection unit detecting passage of the first fixed point of the imaging device; and a second detection unit detecting passage of the second fixed point of the imaging device. The good or bad judgment device performs the inspection of the foreign matter based on the image pickup signal during a period from when the first detection unit detects the image to when the second detection unit detects the image. To be Foreign matter inspection apparatus of Akira film. 2. An annular road including a section separated by the first fixed point and the second fixed point on the line is provided, and a plurality of the imaging devices are provided on the annular road. In order to move in the traveling direction, it is possible to circulate in a certain direction along the annular road, and the pass / fail judgment device inspects the foreign matter based on an imaging signal from each imaging device circulating along the annular road. 2. The apparatus for inspecting foreign matter of a transparent film according to claim 1, wherein the inspection of the entire surface of the transparent film is performed by continuously repeating the steps.