JP2001074666A - Foreign matter inspecting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a foreign matter inspecting apparatus discriminating between the image pattern of an air bubble containing foreign matter and that of an air bubble containing no foreign matter by fixed independent inspection to recognize only the air bubble containing foreign matter as a flaw. SOLUTION: A foreign matter inspecting apparatus applying image processing to the surface of a transparent film or sheet 10 to detect the inferior foreign matter 15 of the transparent film or sheet 10 has a foreign matter recognizing means discriminating between a detection pattern based on an air bubble with foreign matter generated around foreign matter 1 being a nucleus and a detection pattern based on an air bubble not containing foreign matter as a nucleus on the basis of the difference between the detection patterns subjected to image processing and recognizing only detection pattern based on the air bubble with foreign matter as an inferior detection pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foreign matter inspection apparatus for selectively recognizing bubbles based on foreign matter attached to the surface of a transparent film or sheet.

[0002]

2. Description of the Related Art Transparent films or sheets are used in various fields of industry today. Such a transparent film or sheet is subjected to a quality inspection such as a foreign substance inspection at the time of manufacture in order to confirm whether or not a predetermined quality requirement is satisfied.

As such a foreign film inspection apparatus for a transparent film, a one-dimensional CCD sensor, a method of judging acceptability based on a transmitted light amount and a scattered light amount by laser scanning, and the like have been put to practical use.

Further, as a fish eye quality inspection apparatus for inspecting fish eyes included in a traveling direction of fish eyes contained in a running film, for example, a fish eye inspection apparatus disclosed in Japanese Patent Application Laid-Open No. 6-242023 is disclosed. A device has been proposed. Here, the fish eye is an optical strain having a gel or a foreign substance as a nucleus and shaped like a fish eye, and it is necessary to distinguish between a fish eye having a gel as a nucleus and a fish eye having a foreign substance as a nucleus. There is.

In this inspection apparatus, a line-shaped light extending in the width direction of the transparent sheet is provided in the middle of a sheet transport line for transporting the transparent sheet in a strip direction, and extends vertically from below toward the lower surface of the transparent sheet. Parallel to the linear light,
A light receiving unit substantially disposed on the same position plane, a line sensor whose resolution is set to 1/3 or less of the minimum object to be measured, and a fisheye image on a moving film are input. The divided defect image and the isolated defect image are measured, and the former is determined as a gel and the latter as a foreign substance.

In such a fish eye inspection apparatus,
By increasing the resolution of the one-dimensional CCD camera to one-third or less of the minimum of foreign matter defects to be measured, fish eye detection is achieved, and the nucleus is a gel fish eye and the nucleus is foreign matter. Can be distinguished from fish eyes.

[0007]

However, in such a fish-eye inspection apparatus, it is necessary to increase the resolution of the one-dimensional CCD camera to one-third or less of the minimum foreign matter defect to be measured. Becomes

When the resolution of the one-dimensional CCD camera is set to a higher value, the field of view of the one-dimensional CCD camera is correspondingly narrowed. Therefore, an expensive high-resolution one-dimensional camera is required to detect foreign substances over the entire width of the protective sheet. It becomes necessary to install a plurality of CCD cameras or to traverse the high-resolution one-dimensional CCD camera in the width direction of the protection sheet.

The present applicant detects bubbles formed on the protective sheet with a one-dimensional CCD camera set at a low resolution, and based on positional information of the detected bubbles, moves a high-resolution image downstream of the low-resolution camera. With a one-dimensional CCD camera with resolution,
By moving the high-resolution camera traversing in the width direction to the bubble generation position, the size of the nucleus generated by the foreign matter contained in the bubble is measured, and the quality of the foreign matter is determined based on the measured dimensions. An apparatus has already been proposed (for example, see Japanese Patent Application No. 10-49602).

However, when a foreign object on a sheet is detected by this method, the high-resolution camera has a narrow camera field of view, so that the high-resolution camera, as shown in FIG. ) Must be moved in the width direction (y-direction) orthogonal to ()). Therefore, the defect D1
And defect D2, the CCD camera is connected to each defect D1,
It is possible to detect the defect D3 by following it, but when detecting a plurality of defects D3, D4, and D5 occurring in the y direction, as shown in FIG. While the camera is following defect D3,
Other defects D4 or D5 scattered in the y direction flow in the sheet flow direction (x direction), and there is a risk that the defect D4 or D5 may be missed.

Therefore, the present invention recognizes only air bubbles containing foreign matter as defects by discriminating a pattern of an image between air bubbles containing foreign matter and air bubbles not containing foreign matter by a fixed and independent inspection. It is an object of the present invention to provide a foreign matter inspection device which enables the inspection.

[0012]

According to the first aspect of the present invention, an image processing is performed on the surface of a transparent film or sheet to detect a defective foreign substance of the transparent film or sheet. In the device, a bubble generated on the film or sheet, a detection pattern based on bubbles with foreign matter that is generated around the foreign matter as a nucleus, and a detection pattern based on bubbles without foreign matter as a nucleus, A foreign matter inspection apparatus characterized by comprising foreign matter recognizing means for distinguishing by a difference between detection patterns processed by image processing and recognizing only a detection pattern based on bubbles with foreign matter as a failure detection pattern.

According to this structure, a detection pattern based on air bubbles generated on a film or a sheet, which is generated around a foreign substance as a nucleus, and a detection pattern based on air bubbles not having a foreign substance as a nucleus, Pattern is distinguished by the difference between the detection patterns processed by the image processing,
Only the detection pattern based on the bubble with foreign matter can be recognized as the defect detection pattern.

According to a second aspect of the present invention, the foreign matter recognizing means illuminates the inspection target portion of the film or sheet, and a bubble included in the inspection target portion illuminated by the illumination means. Imaging means for capturing an image based on the scattered light scattered from the camera; and performing a binarization process with a predetermined threshold set on the inspection target image captured by the imaging means to obtain a detection pattern based on the bubbles. Where the detection pattern exceeds the predetermined threshold, three or more detection patterns are determined to be defective detection patterns based on bubbles with foreign matter, and the other detection patterns are distinguished and determined as detection patterns based on bubbles without foreign matter. 2. The foreign matter inspection device according to claim 1, further comprising: a quality judgment unit that performs the quality judgment.

According to this structure, the inspection target portion of the film or sheet is illuminated by the illuminating means. If the inspection target portion has bubbles, the illumination light is scattered based on the bubbles. This scattered light is imaged by the imaging means.

By setting a predetermined threshold value from the inspection object image picked up by the image pickup means, a binarization process is performed, and a detection pattern based on the bubbles is obtained. Here, since the scattered light based on the bubble in which the foreign substance is mixed has a maximum luminance point based on the foreign substance and two maximum luminance points based on the boundary of the bubble for one bubble, the threshold value is determined by this binarization processing. Are observed as three or more detection patterns. On the other hand, since the scattered light based on bubbles without foreign matter has only two maximum brightness points based on the boundary for one bubble, the portion exceeding the threshold value by this binarization processing is observed as two detection patterns. Is done.

With this arrangement, three or more detection patterns exceeding a predetermined threshold in this detection pattern are determined to be defective detection patterns based on bubbles with foreign matter, and the other detection patterns are detected based on bubbles without foreign matter. It is possible to determine whether or not there is an air bubble with a foreign substance by the good / bad determination means.

According to a third aspect of the present invention, the foreign matter inspection apparatus includes a transport unit that transports the film or sheet to an imaging position of the imaging unit, and the illumination unit includes the film transported by the transport unit. Or, a linear illumination unit arranged and illuminated such that an optical axis is oblique to the inspection target portion across the width direction of the sheet, and the imaging unit is an inspection target portion illuminated by the illumination unit. 3. The foreign matter inspection apparatus according to claim 2, wherein the apparatus is a line sensor camera which takes an image with an optical axis arranged at right angles to the inspection target part.

According to this structure, the film or sheet conveyed by the conveying means is arranged so that the optical axis is oblique to the portion to be inspected in the width direction of the film or sheet at the imaging position. The inspection target site illuminated by the line-shaped illumination unit is illuminated by the line sensor camera whose optical axis is arranged at right angles to the inspection target site.

As a result, since the optical axes of the illumination means and the imaging means are deviated, the imaging means does not directly image the illumination light or its reflected light, so that the dark field image is scattered due to bubbles. Light can be clearly imaged as luminance information. As a result, a luminance signal based on bubbles can be reliably detected even by a low-resolution CCD camera. Further, since the film or sheet continuous in the length direction is imaged by a line sensor camera arranged only in the width direction of the film or sheet, even if the number of expensive high-resolution CCD cameras is small, Inspections can be carried out.

According to a fourth aspect of the present invention, the illuminating means includes:
It is arranged on one side of the transparent film or sheet and irradiates light from one side toward the transparent film or sheet, and the imaging means is arranged on the same side as the illumination means is arranged. A foreign matter inspection apparatus according to claim 2.

With such a configuration, the illumination light applied to the transparent film or sheet is not limited to a parallel light flux, and may be a scattering light source as the illumination means when there is no optical distortion or foreign matter. Through a transparent film or sheet,
Only the scattered light based on the bubbles will be input to the imaging means. As a result, in the imaging screen, only the scattered light based on the bubbles is clearly imaged with respect to the dark-field image, and the binarization process can easily distinguish and determine the bubbles with foreign matter and the bubbles without foreign matter. .

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. Parts and members that are the same or equivalent to those in the description of the related art will be described with the same reference numerals.

First, defective foreign substances which can be inspected by the foreign substance inspection apparatus of the present invention will be described. Generally, in a transparent film or sheet, an optical distortion called a fish-eye-like shape called a fish eye may be generated in a manufacturing process. Most of these fish eyes have foreign matters or gels as nuclei and bubbles are formed around them, and fish eyes containing only bubbles are rare. Of which
As shown in FIG. 1, a foreign matter 1 becomes a core part and a bubble part 2 formed around the core part is a foreign matter defect. It should be noted that the fish eye having gel as a component of the transparent sheet as a nucleus is treated as not having a foreign matter defect like the fish eye having only air bubbles.

For example, in a sheet for protecting a photomask used in manufacturing a printed wiring board, the minimum size of foreign matter generated on the surface is about 15 microns. This one
It is known that the presence of foreign matter of 5 microns or more generates bubbles of 50 microns or more. The protective sheet in which air bubbles based on the foreign matter are present is defective, but the air bubbles having air bubbles but not based on the foreign matter are considered as defectives for protecting the photomask because they transmit light rays. Not.

The foreign matter inspection apparatus according to this embodiment performs image processing on the surface of such a transparent film or sheet so that a detection pattern based on bubbles with foreign matter and a detection pattern based on bubbles without foreign matter as nuclei can be obtained. This is an apparatus that selectively detects bubbles associated with foreign matter attached to the surface by distinguishing and recognizing them based on differences in detection patterns.

As shown in FIG.
A transparent film or sheet (hereinafter, simply referred to as a transparent sheet 10) having a width of several tens cm to several meters extending continuously in the length direction in a belt shape is transported several meters in a direction indicated by an arrow x by a pair of rollers 11 or the like. It is transported at an appropriate speed of about to several tens m / min.

An illumination device 12 for irradiating light obliquely from one side of the transparent sheet 10 to be inspected toward the transparent sheet 10 is provided. The light from the illuminating device 12 is a line beam that spreads in the width direction of the transparent sheet 10 with a width equal to or slightly wider than the width of the transparent sheet 10.

[0029] Immediately above the illuminated portion (inspection target portion) 13 illuminated by the illuminating device 12, the imaging device 1 is provided.
4 are arranged. In this example, the imaging device 14 can capture images over the entire width of the transparent sheet 10 in the width direction (y direction) by a configuration in which a plurality of one-dimensional CCD cameras are arranged in the width direction (y direction). Have been. Further, a black shielding plate 14b is provided on the outer periphery of the imaging field 14a of the imaging device 14 so as to prevent camouflage light from entering the imaging surface 14a.

The imaging device 14 is connected to an image signal processing device 17 via an A / D converter 16. The image signal processing device 17 distinguishes a detection pattern based on bubbles with foreign matter from a detection pattern based on bubbles with no foreign matter as a nucleus based on a difference between detection patterns processed by image processing. A foreign object recognizing means for recognizing only the pattern as a defect detection pattern is provided.

Next, the illuminating device 12 thus arranged
An optical system in which bubbles are imaged by the camera and the imaging device 13 will be described.

As shown in FIG. 3A, when there are no bubbles in the sheet 10, the illuminating light L illuminated from the illuminating device 12 passes through the sheet 10 as it is and is applied to the imaging surface 14a of the imaging device 14. No light is incident. On the other hand, when air bubbles 15 are present in the sheet 10, FIG.
As shown in (b), the illumination light L is scattered by the bubbles 15 to generate scattered light S. Part of this scattered light S is
The air bubbles 15 are incident on the imaging surface 14a, whereby the bubbles 15 are imaged by the imaging device 14.

The location of the illuminating device 12 may be on the upper surface of the sheet 10 as shown by the broken line in FIG. In this case, as shown in FIG. 4A, when the light beam illuminated from the illumination device 12 has no air bubbles in the sheet 10,
The light does not pass through the sheet 10 and directly enter the imaging device 14. On the other hand, when the sheet 10 has bubbles 15, as shown in FIG.
5, and the scattered light S is imaged by the imaging device 14.

It is to be noted that the illuminating device 12 may be similarly provided on both the upper surface side and the lower surface side. In addition, as long as the scattered light S based on the bubbles is incident on the imaging device 14 and the scattered light S based on the bubbles can be identified, the arrangement of the illumination device 12 and the imaging device 14 is not limited. Further, the illumination device 12 and the imaging surface 1 are arranged so that the camouflage light does not enter the imaging surface 14a.
A light-shielding plate may be provided at an appropriate position at a position where the field of view is not restricted between the light-shielding plate and the light-receiving plate 4a.

Thus, the sheet 10 conveyed by the conveying means is illuminated by the linear illuminating means arranged obliquely with respect to the portion 13 to be inspected in the width direction (y direction) of the sheet 10. You. The inspection target portion 13 illuminated thereby is imaged by the line sensor camera 14 whose optical axis is arranged at right angles to the inspection target portion 13.

In the foreign matter inspection apparatus of this embodiment, light is emitted obliquely toward the transparent sheet 10 and an image of the transparent sheet 10 is taken vertically from directly above, so that it is directly transmitted to the line sensor camera 14. Since no light enters, this imaging screen is basically a dark-field image.

The image pickup signal picked up by the image pickup device 14 is A / D converted by the A / D converter 16 and sent to the image signal processing device 17. This image signal processing device 17
Performs a binarization process on an image signal by setting a predetermined threshold value.

FIG. 5 (a) shows a two-dimensional image of the input image in the case of bubbles without foreign matter (bubbles based on gel).
As shown in FIG. 2, an annular luminance portion 19 is formed in a dark-field background 18, and an inner portion 20 of the annular luminance portion 19 is formed.
Form a dark portion similar to the background 18.
The annular luminance portion 19 is a portion corresponding to the boundary of the bubble 15. At the boundary of the bubble 15, the illumination light L is scattered to generate scattered light S, and the scattered light S is captured by the imaging device 14. I have. In the interior 20, there is a gel that forms the air bubbles 15, but since this gel is substantially optically transparent,
This scattered light S is not generated, and the inside 20 is a substantially uniform dark portion. Thereby, in this example, this boundary is formed along the outline (peripheral edge) of the bubble 15.

FIG. 5A shows the light intensity on the line 21 passing through the center of the annular luminance portion 19, and is shown in FIG. In this figure, from the left side, the dark part (18) -the light part (1)
9) -dark part (20) -light part (19) -dark part (18) are clearly drawn, and two light parts (19) formed along the outline of the bubble 15 by setting an appropriate position as a threshold. , 1
It is possible to obtain a detection pattern including 9). In this detection pattern, there are two places where a predetermined threshold is exceeded.

Next, the case of a bubble having the foreign substance 1 is shown in FIG.
This will be described with reference to FIG. Here, FIG. 6 shows the case where there is one foreign substance 1, and FIG. 7 shows the case where there are two foreign substances 1.

In each case, as in FIG. 5, an annular luminance portion 19 is formed in a dark-field background 18. The inside 20 of the annular luminance portion 19 forms a dark portion similar to the background 18. However, in FIG. 6, one luminance portion 22 is formed in the inside 20, and in FIG. 7, two luminance portions 22, 22 are formed.

The annular luminance portion 19 is a portion corresponding to the boundary between the bubbles 15. At the boundary between the bubbles 15, the illumination light L is scattered to generate scattered light S, and the scattered light S is generated by the imaging device 14. It has been imaged. Luminance portions 22 are formed in the interior 20 according to the number of foreign substances 1 forming the bubbles 15. The luminance section 22 indicates a boundary between the foreign substance 1 and the bubble section 2, and scattered light S is generated at this boundary, and the image is captured by the imaging device 14.

FIG. 6A shows the light intensity on the line 21 passing through the center of the annular luminance portion 19 as shown in FIG.
(B). In FIG. 6B, from the left side, a dark portion (18) -bright portion (19) -dark portion (20) -bright portion (22)
-The dark part (20)-the bright part (19)-the dark part (18) are clearly drawn, and the bubble 15
A detection pattern having three bright portions, that is, two bright portions (19, 19) formed along the contour of (1) and one bright portion (22) formed along the contour of the foreign matter can be obtained. .
In this detection pattern, there are three places where a predetermined threshold is exceeded.

Similarly, this FIG.
FIG. 7 shows the light intensity on a line 21 passing through the center of FIG.
(B). In FIG. 7B, from the left side, a dark portion (18) -bright portion (19) -dark portion (20) -bright portion (22)
-The dark part (20)-the light part (22)-the dark part (20)-the light part (19)-the dark part (18) are clearly drawn, and by setting an appropriate position as a threshold, along the contour of the bubble 15 It is possible to obtain a detection pattern including four bright portions, that is, two bright portions (19, 19) formed and two bright portions (22, 22) formed along the contour of the foreign matter. In this detection pattern, three or more portions exceed a predetermined threshold.

As described above, in any of the detection patterns of the bubbles 15 based on the foreign matter, three or more of the detection patterns exceed the predetermined threshold value. On the other hand, the detection patterns based on the bubbles 15 containing no foreign matter are the predetermined patterns. Since there are two places where the threshold is exceeded, the pass / fail judgment of the pass / fail judgment means should be distinguished as a defect detection pattern based on bubbles with foreign matter and a bubble detection pattern based on foreign matter based on the difference in the number of detection patterns. Can be.

[0046]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific examples of the present invention will be described with reference to embodiments. In this embodiment, there is provided a foreign matter inspection apparatus for inspecting foreign matter on a protective sheet of a photomask having a width of 1200 mm used in manufacturing a printed wiring board. The minimum measurement size of foreign matter required in this protective sheet is 1
If there is a foreign substance of about 5 microns and 15 microns or more, the size of the generated bubble part becomes 50 microns or more.

FIG. 2 shows the configuration of the foreign substance inspection apparatus. As the lighting device 12,
A rod-shaped high-frequency fluorescent lamp is used.
The sheet 10 is slanted toward the downstream side from the upstream side of the sheet.
Is illuminated over the entire width direction. Immediately above the illumination portion 12, the imaging device 1 is orthogonal to the surface of the sheet 10.
Twelve line sensor cameras 4 are arranged in parallel in the width direction. This line sensor camera
4096-bit light receiving elements are arranged in one row,
The resolution of the camera is 0.012 mm, and the field of view is about 105 mm per unit.

Further, a black shielding plate is provided to extend the field of view of the camera. This prevents illumination light illuminated from obliquely behind the camera from being directly input to the field of view of the camera. Thereby, it is possible to capture an image over a width of 1200 mm of the protective sheet.

In such a configuration, the protective sheet is
The sheet is transmitted at a line speed of 0 m / min, the sheet is illuminated by a fluorescent lamp, and scattered light based on bubbles is imaged by a camera. An output signal from this camera is converted to an A / D converter 16.
A / D conversion is performed, and binarization processing is performed by the image processing device 17, whereby bubbles and foreign substances can be recognized based on the number of luminance points of the detection pattern. Further, according to such an apparatus configuration, since the camera does not traverse in the lateral direction, it is possible to recognize the presence or absence of a foreign object without missing.

The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and even if there is a design change or the like without departing from the gist of the present invention. Included in this invention.

For example, in the above embodiment, the foreign object is detected while the transparent sheet is being sent. However, when the transparent sheet is not sent out, the illuminating device or the CCD camera is connected to the transparent sheet using an XY table or the like. May be arbitrarily moved in the plane direction. Further, the imaging device is not limited to a one-dimensional CCD camera, but may be a two-dimensional CCD camera.

[0052]

As described above, according to the first aspect of the present invention, detection based on air bubbles generated on a film or a sheet, and air bubbles with foreign matter generated around the foreign matter as nuclei. The pattern and the detection pattern based on the bubble not having the foreign substance as a nucleus are distinguished by the difference between the detection patterns processed by the image processing, and only the detection pattern based on the bubble with the foreign substance can be recognized as the defective detection pattern.

According to the second aspect of the present invention, the scattered light based on the air bubbles is imaged by the imaging means, and a predetermined threshold value is set from the image of the image to be inspected to perform the binarization processing and the air bubbles are generated. According to this detection pattern, according to this detection pattern, the scattered light based on the bubble with the foreign matter is, in addition to the two maximum brightness points based on the boundary of the bubble for one bubble, the maximum based on the foreign matter. Since there are luminance points, three or more detection patterns exceeding a predetermined threshold in this detection pattern are determined to be defective detection patterns based on bubbles with foreign substances, and the other detection patterns are detection patterns based on bubbles without foreign substances. It is possible to determine whether or not there is an air bubble with a foreign substance by the good / bad determination means.

According to the third aspect of the present invention, the film or sheet conveyed by the conveying means is arranged such that the optical axis is oblique with respect to the portion to be inspected in the width direction of the film or sheet at the imaging position. The inspection target site illuminated by the arranged linear illumination means and illuminated thereby,
Since an image is taken by a line sensor camera whose optical axis is arranged at a right angle to the inspection target part, this imager is
Since the illumination light or its reflected light is not directly imaged,
Scattered light based on bubbles can be clearly captured as luminance information from a dark-field image. As a result, a luminance signal based on bubbles can be reliably detected even by a low-resolution CCD camera. Further, since the film or sheet continuous in the length direction is imaged by a line sensor camera arranged only in the width direction of the film or sheet, even if the number of expensive high-resolution CCD cameras is small, Inspections can be carried out.

According to the fourth aspect of the present invention, the illuminating light applied to the transparent film or sheet is not limited to a parallel light beam, and a scattered light source is used as the illuminating means when there is no optical distortion or foreign matter. Even if it is transmitted, only the scattered light transmitted through the transparent film or sheet and based on the bubbles is input to the imaging means. As a result, in the imaging screen, only the scattered light based on the bubbles is clearly imaged with respect to the dark-field image, and the binarization process can easily distinguish and determine the bubbles with foreign matter and the bubbles without foreign matter. .

Thus, by identifying a pattern of an image of bubbles containing foreign matter and bubbles not containing foreign matter by a fixed and independent inspection, it is possible to recognize only bubbles containing foreign matter as defects. A practically useful effect of being able to provide a foreign matter inspection device that performs the inspection.

[Brief description of the drawings]

FIG. 1 is a schematic view of a foreign substance applicable in an embodiment of the present invention.

FIG. 2 is a diagram illustrating a device configuration according to an embodiment of the present invention.

FIGS. 3A and 3B are diagrams illustrating the state of incidence of scattered light on an imaging unit when illuminated from obliquely below the upstream side of a transparent sheet. FIG. 3A illustrates a case where there is no bubble, and FIG. , Indicates the presence of bubbles.

FIGS. 4A and 4B are diagrams illustrating the state of incidence of scattered light on the image pickup unit when illuminated from obliquely above the upstream side of the transparent sheet. FIG. 4A illustrates a case where there is no bubble, and FIG. , Indicates the presence of bubbles.

FIGS. 5A and 5B are diagrams illustrating a two-dimensional image of an input image of a bubble having no nucleus and a state where the input image is binarized.

FIGS. 7A and 7B are diagrams illustrating a two-dimensional image of an input image of a bubble having one nucleus and a state where the image is binarized.

FIGS. 7A and 7B are diagrams illustrating a two-dimensional image of an input image of a bubble having two nuclei and a state where the image is binarized.

FIGS. 8A to 8C are diagrams for explaining a state of missing a defective image in the prior art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Foreign substance 2 Bubble part 10 Transparent sheet (film) 12 Illumination device 13 Inspection part 14 Imaging device (CCD camera) 16 A / D conversion device 17 Image processing device

Claims (4)

[Claims] 1. An apparatus for detecting a defective foreign substance included in a transparent film or sheet by imaging a surface of the transparent film or sheet and performing image processing, the air bubbles being generated on the film or sheet. The detection pattern based on the bubbles with foreign matter generated around the foreign matter as the nucleus and the detection pattern based on the bubbles not having the foreign matter as the nucleus are distinguished by a difference between the detection patterns processed by the image processing. A foreign matter recognizing means for recognizing only a detection pattern based on the information as a failure detection pattern. 2. The foreign matter recognizing means includes: an illuminating means for illuminating a portion to be inspected of the film or sheet; and scattered light scattered from bubbles of the inspected portion by being illuminated by the illuminating means. An imaging unit that captures an image based on the image, and a binarization process in which a predetermined threshold is set on the inspection target image captured by the imaging unit to obtain a detection pattern based on air bubbles. A place exceeding a predetermined threshold value determines three or more detection patterns as failure detection patterns based on bubbles with foreign matter,
2. The foreign matter inspection device according to claim 1, further comprising: a good or bad determination unit that distinguishes and determines other detection patterns as a detection pattern based on bubbles without foreign matter. 3. The foreign matter inspection apparatus according to claim 1, further comprising a conveying unit configured to convey the film or the sheet to an imaging position of the imaging unit, wherein the illuminating unit is arranged in a width direction of the film or the sheet conveyed by the conveying unit. A linear illumination unit arranged and illuminated such that an optical axis is oblique to the inspection target site over the inspection target site; and the imaging unit sets the inspection target site illuminated by the illumination unit as the inspection target site. 3. The foreign matter inspection apparatus according to claim 2, wherein the apparatus is a line sensor camera that takes an image with an optical axis disposed at a right angle to the image sensor. 4. The illuminating means is arranged on one side of the transparent film or sheet to irradiate the transparent film or sheet with light from one side, and the imaging means is the same as the illuminating means is arranged. The foreign matter inspection device according to claim 2, wherein the foreign matter inspection device is arranged on a side of the foreign matter inspection device.