JP2008180705A - Defect detection device for optically transparent film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a defect detection device for an optically transparent film capable of enhancing the defect detection accuracy. <P>SOLUTION: An imaging means 1 for imaging the appearance of the optically transparent film A from one surface side is formed. A guide means 2, arranged on the other surface side of the optically transparent film A at an imaging time by the imaging means 1, is formed. This defect detection device for the optically transparent film A is equipped with a detection means 3 for detecting defects of the optically transparent film A, from an image acquired by imaging by the imaging means 1. The device is also equipped with an adhering means 4 for making the optically transparent film A adhere to the surface of the guide means 2, by removing the air between the other surface of the optically transparent film A and the guide means 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is a light transmissive film used for the purposes of antireflection, scattering prevention, heat ray prevention (blocking), heat insulation, antifouling, durability (protection), etc. in applications such as optical applications, architectural applications, and automotive applications. The present invention relates to an apparatus for detecting a defect of (light transmissive film).

Conventionally, as the light transmissive film as described above, a film in which an adhesive layer or a different refractive index layer is formed on a base film by coating or laminating has been proposed. Such a light transmissive film has defects such as thickness variation due to coating repelling, nuclei due to foreign matter, and thickness variation due to gelation, and this defect causes characteristics of the light transmissive film (for example, antireflection, etc.) Optical characteristics) may be impaired. Thus, for example, it is conceivable to detect a defect using the film inspection method described in Patent Document 1. The coating inspection method described in Patent Document 1 irradiates light while a light transmissive film (antireflection film) travels along the outer surface of the guide roller, and images the surface of the light transmissive film in this state. The image data is processed by the data processing unit to detect defects.
JP 2006-208196 A

  However, in the coating inspection method described in Patent Document 1, air may be interposed between the light transmissive film and the outer surface of the guide roller. For this reason, the reflected light from the light transmissive film is used to detect defects. There is a problem in that unnecessary reflected light is also mixed and defect detection accuracy is lowered.

  This invention is made | formed in view of said point, and it aims at providing the defect detection apparatus of the light transmissive film which can raise the detection accuracy of a defect.

The defect detection apparatus for a light transmissive film A according to claim 1 of the present invention includes an image pickup means 1 for picking up an appearance of the light transmissive film A from _one side A ₁ side, and a light transmissive film A at the time of image pickup by the image pickup means 1. defects other guide means 2 disposed on one a ₂ side, the light transmissive film a and a detecting unit 3 for detecting a defect of a light transmissive film a from the obtained image by the image pickup by the image pickup means 1 In the detection device, a contact means 4 for removing the air between the other side A _{2 of} the light transmissive film A and the guide means 2 and bringing the light transmissive film A into close contact with the surface of the guide means 2 is provided. It is characterized by comprising.

  The defect detection apparatus for the light transmissive film A according to claim 2 of the present invention is characterized in that in claim 1, at least one of the guide means 2 and the contact means 4 is colored.

  The defect detection apparatus for light transmissive film A according to claim 3 of the present invention is characterized in that, in claim 1 or 2, the contact means 4 is a liquid.

In the invention of claim 1, the light transmitting film A is brought into close contact with the surface of the guide means 2 by the contact means 4, and the air between the one surface A ₂ on the guide means 2 side of the light transmitting film A and the guide means 2 is discharged. by eliminating, it is possible to suppress the reflected light from one side a ₂ of the guide means 2 side of the light transmissive film a, to increase the detection accuracy of the defect reduces the mixing of unnecessary reflection light to the detection of the defect It is something that can be done.

  In the invention of claim 2, at least one of the guide means 2 and the contact means 4 can easily absorb the light passing through the light-transmitting film A, and the number of reflected light unnecessary for detecting the defect is further reduced. As a result, the defect detection accuracy can be increased.

  In the invention of claim 3, it becomes easy to fill the contact means 4 between the light-transmitting film A and the guide means 2, and further reduces the presence of reflected light unnecessary for defect detection, thereby improving the defect detection accuracy. It can be raised.

  Hereinafter, the best mode for carrying out the present invention will be described.

  The defect detection apparatus for the light transmissive film A of the present invention is used in applications such as optical applications, architectural applications, and in-vehicle applications, such as antireflection, scattering prevention, heat ray prevention (blocking), heat insulation, antifouling, and durability (protection). It is an apparatus for detecting the defect of the light transmissive film (film which has light transmittance) A used for the purpose of. Examples of the light transmissive film A include, but are not limited to, those used as an antireflection film (AR film) for a display such as a liquid crystal display.

The light transmissive film A as described above is formed by laminating a plurality of coating layers on the surface of a synthetic resin base film such as a polyester film, and is applied to form a coating layer. The coating agent gels, and the gelled product adheres to the surface A ₁ of the light-transmitting film A to form defects as foreign matter, or non-uniform coating of the coating agent occurs due to contamination or contamination. May form defects. In the present invention, it is suitably used to detect defects coating due to non-uniformity of the light transmissive film A coating agent according to the surface A defects or contamination due to foreign matter adhering to _one.

  As shown in FIG. 1, the defect detection apparatus for the light transmissive film A of the present invention includes an imaging means 1, guide means 2, detection means 3, close contact means 4, transport means 5, illumination means 6, and the like. ing.

Imager 1 has been made to image a strip of the external appearance of the light transmissive film A which is continuously conveyed at a constant speed by the conveying means 5 from one side (surface) A ₁ side, for example, formed by a CCD camera or the like In addition, a line camera or the like that images the entire appearance of the light transmissive film A can be used.

Guide means 2 is an intended to be located in other one side (back surface) A ₂ side of the light transmissive film A at the time of imaging by the imaging unit 1, the occurrence of wrinkles by supporting the light transmissive film A during imaging The image pickup means 1 and the light transmissive film A are positioned to prevent the occurrence of defocusing. Guide means 2 may be formed of a roller which rotates while being contacted via contact means 4 to the one side (back surface) A ₂ of the light transmissive film A.

  The detection means 3 is for detecting a defect of the light transmissive film A from an image obtained by imaging by the imaging means 1, and a general-purpose electronic computer equipped with a display can be used. For example, the detection unit 3 uses image processing that is generally performed widely, performs arithmetic processing on an image obtained by imaging by the imaging unit 1, and visually confirms the light transmission. What can analyze and detect the defect of the property film A can be used.

The close contact means 4 is for excluding air between the one side A _{2 of} the light transmissive film A and the guide means 2 so that the light transmissive film A is in close contact with the surface of the guide means 2. In the case shown in FIG. 1, a tack film is used as the contact means 4. Tack film is to contact with a tacky and the one surface (back surface) A ₂ of surface and light transmissive film A guide means 2 to the surface. Such a close contact means 4 is suspended in an endless loop between the guide means 2 and the auxiliary roller 9 provided below the guide means 2 and is advanced in one direction by the rotational drive of the guide means 2 and the auxiliary roller 9. Can do.

In the present invention, at least one of the surface of the guide means 2 and the close contact means 4 can be colored such as black, so that the light that has passed through the light transmissive film A is transmitted by the guide means 2 and the close contact means 4. absorbed able to hardly reflected, it is capable of suppressing the reflected light from one side a ₂ of the guide means 2 side of the light transmissive film a. For example, when the surface of the guide means 2 is colored such as black by painting or the like, a transparent tack film or the like can be used as the contact means 4, and a pigment or the like is blended as the contact means 4 so that it is colored such as black. When a tack film is used, the color of the surface of the guide means 2 is not particularly limited.

  The transport means 5 is for continuously transporting the long belt-like (sheet-like) light-transmitting film A at a constant speed. For example, the conveying means 5 includes a feeding drum 10 in which the light transmissive film A is wound in a roll shape, a driving means 11 such as a motor for rotating the drum 10 to sequentially feed the light transmissive film A, and after detecting the defect. And a take-up drum 12 for taking up the light-transmitting film A.

The illuminating means 6 irradiates the light transmissive film A with light from _one side (front surface) A1 side at the time of imaging by the imaging means 1, and includes, for example, an illumination tool 6a such as a three-wavelength fluorescent lamp and a color tone filter 6b In addition to this, the illumination means 6 may be colored illumination that emits light of a specific wavelength such as red, colorless illumination (white illumination), or the like.

  And when detecting the defect of the transparent film A using this invention, it carries out as follows. First, the feeding drum 10 is rotationally driven by the driving means 11 so that the light transmissive film A wound around the drum 10 is sequentially fed and conveyed to the take-up drum 12 at a constant speed. Further, the light transmissive film A is conveyed between the feeding drum 10 and the take-up drum 12 while being in contact with the surface (outer surface) of the guide means 2.

Here, although the conveyance speed of the light transmissive film A can be suitably set according to the capability of the imaging means 1 and the conveyance means 5, etc., it can be 0.05-50 m / sec, for example. Further, one side (back side) A _{2 of} the light transmissive film A and the guide unit 2 are brought into contact with each other through the contact unit 4. In this case, the contact means 4 is filled so as to stay between the one side A ₂ of the light transmissive film A and the guide means 2, or between the one side A ₂ of the light transmissive film A and the guide means 2. The close contact means 4 can be filled to circulate. When the close contact means 4 is circulated, there are cases where it is circulated in the opposite direction to the case where it is circulated in the same direction as the transport direction of the light transmissive film A. When the contact means 4 is circulated in the same direction as the transport direction of the light transmissive film A, the guide means 2 is driven so as to rotate (forward rotation) in the same direction as the transport direction of the light transmissive film A. When the contact means 4 is circulated in the direction opposite to the transport direction of the film A, the guide means 2 is driven to rotate (reversely rotate) in the direction opposite to the transport direction of the light transmissive film A. The rotation speed of the guide means 2 is such that the contact means 4 is sufficiently supplied between one side A ₂ of the light transmissive film A and the guide means 2 and the material (viscosity) of the contact means 4 and the light transmissive film A. Although it can set suitably according to the conveyance speed of this, for example, it can be set as peripheral speed 0.05-100 m / min.

In this invention, the external appearance of the light transmissive film A is imaged by the imaging means 1 while irradiating the light transmissive film A conveyed as described above with the illumination means 6. The illuminating means 6 is disposed almost directly above the guide means 2, and light is irradiated on _one surface A ₁ of the surface (upper surface) of the light transmissive film A. Further, the image pickup means 1 is disposed at a position inclined by about 45 ° from directly above the guide means 2, and obliquely above one side A ₁ of the light transmissive film A in a portion irradiated with light by the illumination means 6. I'm trying to capture images from. Then, so as to detect a defect based on the image capturing an image of one side A ₁ of the light transmissive film A imaged by the imaging unit 1 to the detecting means 3. Moreover, the defect of the whole light transmissive film A is detectable by conveying the light transmissive film A over the full length.

In the present invention, through the contact means 4 are brought into close contact with the light transmissive film A on the surface of the guide means 2, exclusion of air between the one side A ₂ and the guide means 2 of the guide means 2 side of the light transmissive film A Like to do. Therefore, it is possible to suppress the reflected light from one side A ₂ of the guide means 2 side of the light transmissive film A. That is, as shown in FIG. 5A, when air is present in the gap S between the one surface (back surface) A ₂ of the light transmissive film A and the outer surface of the guide means 2 without the contact means 4 interposed. Are light L ₁ reflected on one side (one side facing the guide means 2 side) A ₁ on the front side of the light transmissive film A, and the back side (guide means 2 side) passing through the light transmissive film A. The light L ₂ reflected on the one surface A ₂ of the one surface facing toward the light is generated, and the light L ₁ and L ₂ are mixed and enter the imaging means 1 while interfering with each other, so that the defect detection accuracy is low. There is a risk. On the other hand, as shown in FIG. 5 (b), when the air gap between the one surface (back surface) A ₂ and guide means 2 on the outer surface of the light transmissive film A with exclusion interposed adhesion means 4, The light L _{2 that} has passed through the light transmissive film A travels toward the contact means 4 and is absorbed by the guide means 2, so that most of the light reflected on the one side A ₂ on the back side of the light transmissive film A is generated. Absent. Therefore, since the light L ₁ reflected by the one surface A ₁ on the surface side of the light transmissive film A enters the image pickup means 1 without interference, the defect detection accuracy can be increased.

  FIG. 2 shows another embodiment. This defect detection device for the light transmissive film A is formed by providing a plate-like guide means 2 instead of the roller guide means 2 of FIG. A pair of pressing rollers 72 and 72 are provided on the surface side of the guide means 2. Moreover, as the contact | adherence means 4, the fluid liquid which is easy to fill between the light transmissive film A and the guide means 2 is used instead of a tack film. Examples of the liquid contact means 4 include volatile solvents such as water (pure water) and methyl ethyl ketone, and oil-based liquids such as essential oil. Moreover, as the supply means 71 for supplying the contact means 4 to the surface of the guide means 2, a tank provided with a nozzle or the like that can discharge the contact means 4 can be exemplified. A receiving container 73 for collecting the liquid contact means 4 is provided below the guide means 2. The contact means 4 collected in the receiving container 73 is returned to the supply means 71, and the contact means 4 can be circulated between the supply means 71 and the receiving container 73. In addition, the defect detection apparatus can include a draining doctor 61 and an air blower 62 for removing moisture from the close contact means 4 attached to the light transmissive film A. Other configurations are the same as those shown in FIG.

In this embodiment, at least one of the surface of the guide means 2 and the contact means 4 can be colored, such as black, so that the light that has passed through the light transmissive film A can be guided by the guide means 2 or the contact means. 4 absorbed able to hardly reflected by the one in which it is possible to suppress the reflected light from one side a ₂ of the guide means 2 side of the light transmissive film a. For example, when the surface of the guide means 2 is colored such as black by painting or the like, transparent liquid water or the like can be used as the contact means 4, and a pigment or the like is blended as the contact means 4 so as to be colored such as black. When the liquid is used, the color of the surface of the guide means 2 is not particularly limited.

And the defect detection apparatus of this embodiment can detect the defect of the transparent film A like the above. That is, the long belt-like light transmissive film A is conveyed from the feeding drum 10 to the winding drum 12 by the conveying means 5, and the light transmissive film A is guided between the feeding drum 10 and the winding drum 12. 2 is conveyed along the surface (outer surface). At this time, the light transmissive film A is conveyed while being pressed against the guide means 2 by the pressing rolls 72 and 72. Further, at least one of the front surface of the guide means 2 and the contact means 4 is colored such as black, and as shown in FIG. 6, the one surface (back surface) A ₂ of the light transmissive film A and the guide means 2 are in contact with each other. To make contact through. In this case, contact means 4 is supplied between the supply means 71 and one surface A ₂ and the guide means 2 of the light transmissive film A, flows between the single-sided A ₂ and the guide means 2 of the light transmissive film A After that, it falls into the receiving container 73 and is collected. In the same manner as described above, the imaging device 1 captures the appearance of the light transmitting film A while irradiating the light transmitting film A with the illumination device 6, and the light captured by the imaging device 1. capturing an image of one side a ₁ of permeable film a on the detection means 3 so as to detect a defect based on the image. This embodiment also has the same effect as described above.

  FIG. 3 shows another example of the guide means 2. The guide means 2 is formed of a rotating roller similar to that shown in FIG. Further, the close contact means 4 is liquid like that of FIG. 2 and is stored in the storage container 20. The contact means 4 can be supplied to the surface of the guide means 2 by immersing a part (lower part) of the guide means 2 in the contact means 4. In addition, as shown in FIG. 4, the guide means 2 of a roller can be arrange | positioned side by side in parallel with the conveyance direction of the light transmissive film A. FIG.

  2, instead of the supply means 71, the receiving container 73, the pressing roll 72, and the plate-like guide means 2, the guide means 2 of the roller of FIG. 3 or FIG. 4, the storage container 20, and the liquid contact means. 4 and other configurations are the same as those in FIG. 2, the defect detection apparatus of the present invention can be formed. Even when this defect detection apparatus is used, defects in the light-transmitting film A can be detected in the same manner as in FIG.

In the present invention, before bringing the light transmissive film A into contact with the guide means 2, a colored pigment such as black is applied to one side (back surface) A ₂ of the light transmissive film A using magic ink or the like. or laminating a film of colored, such as, or by pasting a colored gel such as black, thereby, the defect may further suppress reflection of light by the one side a ₂ of the light transmissive film a The detection accuracy can be increased.

  Hereinafter, the present invention will be described specifically by way of examples.

(Example 1)
A light-transmissive film having a length of 4000 m was formed by providing a coating layer having a thickness of 2 μm (main component is silica) on the surface of a polyester film having a thickness of 100 μm.

  Defects (adhesion of gelled products) generated in the light transmissive film were detected by the defect detection apparatus shown in FIG. At this time, the outer surface of the guide means was colored black, and transparent pure water was used as the contact means. The light transmissive film was conveyed at 5 m / min, and the guide means was rotated forward at a rotational speed of 20 m / min. Further, a 50 W three-wavelength fluorescent lamp was used as the illumination means, and was installed at a position 500 mm above the guide means. And when the defect was detected over the full length of the light transmissive film, the number of detected defects was 28. On the other hand, when the contact means was not used, the number of detected defects was three, and the defect detection accuracy was lower than when the contact means was used as described above.

(Example 2)
It detected with the defect detection apparatus using the guide means 2 shown in FIG. At this time, the outer surface of the guide means was colored black, and transparent pure water was used as the contact means. Other matters were the same as in Example 1. And when the defect was detected over the full length of the light transmissive film, the number of detected defects was 20. On the other hand, when the contact means was not used, the number of detected defects was two, and the defect detection accuracy was lower than when the contact means was used as described above.

  In addition, when the defect was visually detected with respect to the light transmissive films of Examples 1 and 2, the number of detected defects was zero.

It is the schematic which shows an example of embodiment of this invention. It is the schematic which shows an example of other embodiment same as the above. It is the schematic which shows a part same as the above. It is the schematic which shows a part same as the above. (A) (b) is the expanded schematic which shows the effect | action of this invention. It is the schematic which shows a part same as the above.

Explanation of symbols

A light transmissive film A ₁ single side A ₂ single side 1 imaging means 2 guide means 3 detection means 4 adhesion means

Claims (3)

  Imaging means for imaging the appearance of the light transmissive film from one side, guide means disposed on the other side of the light transmissive film during imaging by the imaging means, and light transmission from an image obtained by imaging by the imaging means In a defect detection apparatus for a light transmissive film comprising a detection means for detecting a defect in a light transmissive film, air between the other side of the light transmissive film and the guide means is excluded to guide the light transmissive film. A defect-detecting device for a light-transmitting film, characterized by comprising an adhesion means for adhering to the surface of the film.   2. The light transmission film defect detection device according to claim 1, wherein at least one of the guide means and the contact means is colored.   The defect detecting device for a light transmissive film according to claim 1, wherein the contact means is a liquid.

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