JP2018063237A - Film inspection method and film production method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film inspection method capable of accurately detecting defects of a resin film, and to provide a film production method capable of obtaining a resin film having an excellent film quality including a step of inspecting the resin film using the same.SOLUTION: A film inspection method includes: projecting light from light projection means toward a resin film; taking transmission light penetrating the resin film or reflection light reflected on the surface of the resin film in an area sensor camera; and detecting defects of the resin film. A filter having light-shielding repeated patterns formed on a transmissive base material or a filter having repeated patterns formed of a light-shielding base material is arranged at a position through projection light passes from light projection means between the light projection means and the resin film, and the position of repeating units of the repeated patterns are moved as the position progresses to a traveling direction, and the repeating units have the same shape in the traveling direction of the resin film and the width direction of the resin film.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a film inspection method for detecting a defect of a resin film and a film manufacturing method including a step of inspecting a resin film using the same.

  Resin films are widely used in various industrial applications, and are produced in a wide variety of fields such as packaging materials, magnetic recording materials, electrical insulating materials, and optical materials. However, as the applications are diversified, the properties and quality required for the resin film and the productivity related to cost reduction are becoming more severe in each application field, and there are many problems to be solved. For example, when using a resin film as various optical films such as liquid crystal display components such as liquid crystal polarizing plates and retardation plates, PDP members, touch panel members, laminated glass members, excellent transparency and scratches, An excellent film quality free from foreign matters is required. For these problems, the film inspection method at the time of film production is important as well as the improvement of the properties of the resin film, and various film inspection methods for checking the film quality of the resin film have been proposed.

  In such a case, a standard image unit with a standard image is installed behind the place where the translucent article is to be placed, so that an image viewed through the translucent article is different from the standard image. There has been proposed a defect inspection apparatus and a defect inspection method for a translucent article capable of finding a portion having a defect in the structure of the translucent article (Patent Document 1).

  Further, in a defect inspection apparatus for a transparent film in a dark room environment, a stage having an arrangement surface on which the transparent film is arranged, and a stage having an arrangement surface on which a latticed chart unit of a lattice drawn on a transparent material is arranged An irradiation unit including a parallel light source installed so as to irradiate light in a direction perpendicular to the arrangement surface on which the transparent film is arranged; and a camera that images the grid chart unit through the transparent film and outputs image data. A transparent film inspection apparatus and a defect detection method having an image processing unit for determining the presence or absence of a defect in the transparent film from the difference between the photographing unit and the lattice chart of the image viewed through the transparent film have been proposed ( Patent Document 2).

JP 2009-139365 A JP2012-2792A

  The defect inspection apparatus and the defect inspection method for a translucent article described in Patent Document 1 use the extraordinary refraction caused by the transmitted light at the defect location in the structure of the translucent article to reveal the defect location in the image of the standard image. It is possible to detect defects with high detection rate by making it easy to search for defects by giving a proper distortion. However, an appropriate light projection by a light projecting unit for accurately detecting defects in the resin film and an optimum standard image shape are not considered.

  The transparent film inspection apparatus and the defect detection method described in Patent Document 2 can accurately detect anomalous refraction caused by a passing light beam at a defective portion in a transparent film with a parallel light source and an image processing unit. Defects in the captured image can be clearly distorted to easily find defects, and defects can be detected with a high detection rate. However, the optimal shape of the chart unit for accurately detecting defects in the resin film is not sufficient.

  An object of the present invention is to provide a film inspection method capable of accurately detecting defects in a resin film, and a film manufacturing method capable of obtaining a resin film having excellent film quality, including a step of inspecting a resin film using the film inspection method. It is to be.

  According to the film inspection method of the present invention, light is projected from the light projecting means toward the resin film, and the transmitted light transmitted through the resin film or the reflected light reflected from the surface of the resin film is taken into the area sensor camera to be resin film. Detect defects. Further, a filter in which a light-shielding repetitive pattern is formed on a transparent material at a position where the projection light from the light projecting means passes between the light projecting means and the resin film, or a repetitive pattern with a light-shielding material. The position of the repeating unit of the repetitive pattern moves in the running direction of the resin film, and the repeating unit is all the same in the running direction of the resin film and the width direction of the resin film. Shape.

  According to the present invention, there are provided a film inspection method capable of accurately detecting defects in a resin film, and a film manufacturing method capable of obtaining a resin film having excellent film quality, comprising a step of inspecting a resin film using the film inspection method. Can do.

FIG. 1 is a schematic view of a film inspection method according to the transmission method of the present invention. FIG. 2 is a schematic view of the film inspection method according to the reflection method of the present invention. FIG. 3 is a schematic view of a specific film production method of the present invention. FIG. 4 is a schematic view of a filter in which the repeating unit of the repeating pattern is circular in the present invention. FIG. 5 is a schematic view of a filter in which the repeating unit of the repeating pattern in the present invention is a square. FIG. 6 is a schematic view of a filter in which the repeating unit of the repeating pattern in the present invention is a cross shape. FIG. 7 is a schematic view of a filter in which the repeating unit of the repeating pattern in the prior art is a square. FIG. 8 is a schematic view of a filter in which a repeating unit having a repeating pattern different from the repeating pattern in the present invention is a regular hexagon. FIG. 9 is a schematic diagram of a standard sample for resin film defect detection evaluation. FIG. 10 is a schematic view of an example of a repeating unit in the present invention. FIG. 11 is a schematic view of an example of a repeating unit different from the repeating unit in the present invention. FIG. 12 is a schematic view of a filter in which the repeating unit of the repeating pattern according to the present invention is a ring shape.

  Hereinafter, preferred embodiments for carrying out the present invention will be described with reference to the drawings. The present invention is not limited to this.

  According to the film inspection method of the present invention, light is projected from the light projecting means toward the resin film, and the transmitted light transmitted through the resin film or the reflected light reflected from the surface of the resin film is taken into the area sensor camera to be resin film. A film inspection method for detecting defects in which a light-shielding repeating pattern is formed on a transparent material at a position where the projection light from the light projecting means passes between the light projecting means and the resin film, Alternatively, a filter in which a repetitive pattern is formed with a light shielding material is disposed. The repeating pattern moves as the position of the repeating unit proceeds in the traveling direction of the resin film, and the repeating unit has the same shape in both the traveling direction of the resin film and the width direction of the resin film.

  The film inspection method of the present invention is suitable for a transparent film inspection method as long as the resin film has high transparency and transmits light, such as scratches on the surface of the film, adhering foreign matter, foreign matter inside the film, bubbles, etc. Defects can be detected.

  As the film inspection method of the present invention, a film inspection method by a reflection method is suitable for a resin film having a high surface reflectance, and it is possible to detect defects such as uneven scratches on the film surface and attached foreign matter.

  A schematic diagram of a film inspection method according to a specific transmission method of the present invention is shown in FIG. The present invention is not limited to this. In the inspection method of FIG. 1, light is projected from a light source 3 that is a light projecting unit onto a traveling resin film 1, and the projected light from the light projecting unit 3 between the light projecting unit 3 and the resin film 1 passes through the position. Place the filter 2. Then, the transmitted light 7 transmitted through the resin film 1 is taken into the area sensor camera 4 through the lens 5, and the defect detection data of the resin film 1 is processed by the data processing device 6.

  A schematic diagram of a film inspection method according to a specific reflection method of the present invention is shown in FIG. The present invention is not limited to this. In the inspection method of FIG. 2, light is projected from the light source 3 that is the light projecting means to the traveling resin film 1, and the projection light from the light projecting means 3 between the light projecting means 3 and the resin film 1 passes through the position. Place the filter 2. Then, the reflected light 8 reflected from the surface of the resin film 1 is taken into the area sensor camera 4 through the lens 5, and the defect detection data of the resin film 1 is processed by the data processing device 6.

  The material of the resin film 1 in the present invention is not particularly limited, and is preferably an amorphous thermoplastic resin or an amorphous material of a crystalline thermoplastic resin. Examples of the amorphous thermoplastic resin include methacrylic resin and polycarbonate. , Polystyrene, polymers having an alicyclic structure, cellulose resins, vinyl chloride, polysulfone, polysulfone ether, and the like. Examples of the crystalline thermoplastic resin include a polyester resin. By making these amorphous, light can be transmitted. In this invention, it is preferable to use the polyester resin which is excellent in the raw material cost of a resin, mechanical strength, etc.

  There is no restriction | limiting in particular in the driving | running | working form of the resin film 1 in this invention, What is necessary is just to drive | work stably, without flapping and wrinkles entering. The traveling speed may be 10 m / min to 500 m / min, but is preferably 50 m / min to 200 m / min. The thickness of the resin film 1 is not particularly limited, and can be 1 μm to 8,000 μm, but 10 μm to 1,000 μm is preferable.

  Although the light source 3 which is a light projection means in this invention does not have a restriction | limiting in particular, It is preferable that it is a surface light source. The average illuminance of the light source 3 is preferably 1,000 LUX or more, particularly preferably 2,000 LUX or more. Further, if the illuminance unevenness is ± 10% or less, it can be dealt with by adjusting the sensitivity on the camera side, but if it exceeds ± 10%, it may become a sensitivity unevenness.

  The area sensor camera 4 and the lens 5 in the present invention are not particularly limited, but the area sensor camera 4 converts a shadow of light taken through the lens 5 into a digital signal by a plurality of photoelectric conversion elements. The area sensor camera 4 preferably has a large number of pixels, and preferably has 21 million pixels with 4092 pixels in the running direction 26 of the resin film and 5104 pixels in the width direction 27 of the resin film. Here, the “width direction of the resin film” referred to in the present invention refers to a direction parallel to the resin film surface and perpendicular to the running direction of the resin film. The lens 5 captures the transmitted light 7 transmitted through the resin film 1 or the reflected light 8 reflected from the surface of the resin film 1 into the camera 4. The lens 5 has a focus function for focusing and an aperture function for adjusting illuminance. It is preferable to have.

  The data processing device 6 in the present invention is not particularly limited, but has a function of detecting a defect of the resin film 1 and performing data processing based on the amount of transmitted light 7 or reflected light 8 received by the area sensor camera 4. It is preferable to have.

  The filter 2 according to the present invention is one in which a light-shielding repetitive pattern is formed on a transparent material or a light-shielding material formed with a repetitive pattern. The filter 2 in which a light-shielding repeating pattern is formed on a transparent material is not particularly limited in form, but the transparent material is formed of glass, and the light-shielding material is placed on the glass. A resin containing the formed pigment is preferred. The form of the filter 2 in which the repetitive pattern is formed with a light-shielding material is not particularly limited, but it is preferable that the repetitive pattern is formed with a thin light-shielding material having a thickness of about 0.1 mm. The light-shielding material is preferably a metal because it is a thin film and has light-shielding properties. The light-shielding repeating pattern is preferably formed by etching a metal.

  The filter 2 according to the present invention moves as the position of the repeating unit of the repeating pattern advances in the traveling direction of the resin film. Here, "the position of the repeating unit moves as it advances in the traveling direction of the resin film" means that when the repeating pattern formed on the filter is observed along the film traveling direction, the repeating units arranged in the film traveling direction are It is not arranged continuously at the same position in the film width direction but arranged at different positions in the film width direction. This will be specifically described with reference to the drawings. FIG. 5 shows an example of the filter in the present invention. When the repeating units 28 are observed along the film running direction 26, the repeating units 28 arranged in the film running direction 26 are arranged and arranged at different positions in the film width direction 27. On the other hand, what is illustrated in FIG. 7 is an example of a filter different from the present invention. When the repeating units 28 are observed along the film running direction 26, the repeating units 28 arranged in the film running direction 26 are arranged at the same position in the film width direction 27.

  When the filter 2 is installed so that the surface of the filter 2 and the surface of the resin film 1 have an angle, such as when an inspection apparatus is installed as shown in FIG. 2, the surface of the filter 2 and the actual film traveling direction 26 Is no longer parallel. In such a case, the resin film 1 traveling from a direction perpendicular to the surface of the filter 2 is observed, and the direction in which the resin film 1 observed at that time flows may be regarded as the film traveling direction.

  If the repeating units arranged in the film running direction are repeated patterns arranged continuously at the same position in the film width direction, the light shielding part at the boundary between the repeating units is a single line extending in the film running direction. It may become like this. If a defect on the resin film occurs at a position that overlaps the position of the light-shielding part, the light-shielding part extends in the film running direction, so the defect always overlaps the light-shielding part. You can't do that. If the repeating unit arranged in the film running direction is a repeating pattern arranged and arranged at different positions in the film width direction, even if a defect on the resin film occurs at a position overlapping the light shielding part of the repeating pattern at a certain point in time, If the defect moves in the film running direction together with the resin film, the defect can be observed at a position that does not overlap the light shielding portion. Thereby, it can suppress that the defect which should be detected is hidden behind a light-shielding part and cannot be detected, emphasizing the defect which should be detected of resin film by repetition of light transmission and light shielding.

  In the filter 2 of the present invention, the shape of the repeating unit 28 of the repeating pattern is the same shape even if the traveling direction 26 of the resin film and the width direction 27 of the resin film are interchanged (hereinafter, this shape is referred to as “resin film The traveling direction 26 and the width direction 27 of the resin film have the same shape ”). When the repeating unit 28 has different shapes in the resin film running direction 26 and the resin film width direction 27, defects can be emphasized in the same degree in the resin film running direction 26 and the resin film width direction 27. Therefore, a difference depending on the direction of detection sensitivity may occur, and a defect in the resin film 1 may not be detected with high accuracy. If the repeating unit 28 has the same shape in the running direction 26 of the resin film and the width direction 27 of the resin film, the defect can be emphasized in the same degree in the running direction 26 of the resin film and the width direction 27 of the resin film. .

  In the filter 2 of the present invention, the repeating unit 28 of the repeating pattern of the filter 2 is preferably circular. By making the repeating unit 28 circular, defects can be emphasized in the same degree in all directions, not limited to the two directions of the running direction 26 of the resin film and the width direction 27 of the resin film.

  In the filter 2 according to the present invention, the repeating unit 28 of the repeating pattern of the filter 2 is preferably ring-shaped. By making the repeating unit 28 into a ring shape, defects can be emphasized in the same degree in all directions, not only in the two directions of the resin film running direction 26 and the resin film width direction 27, Defects can be detected particularly accurately by increasing the contrast with the transmission part.

  4, 5, 6, and 12 show schematic diagrams of examples of filters having a repetitive pattern in the present invention (FIG. 4: filter A21, FIG. 5: filter B22, FIG. 6: filter C23, FIG. 12: Filter F48). The repeating unit 28 of the repeating pattern is circular (FIG. 4), square (FIG. 5), cross (FIG. 6), and ring (FIG. 12). In either case, the position of the repeating unit 28 moves as it advances in the running direction 26 of the resin film, and the repeating unit 28 has the same shape in the running direction 26 of the resin film and the width direction 27 of the resin film.

  7 and 8 show schematic diagrams of examples of filters having a repetitive pattern different from the present invention (FIG. 7: filter D24, FIG. 8: filter E25). Each of the repeating units 28 of the repeating pattern is a square (FIG. 7) and a regular hexagon (FIG. 8). In the filter D24, the square repeating unit 28 has the same shape in the traveling direction 26 of the resin film and the width direction 27 of the resin film, but the repeating unit 28 aligned in the traveling direction 26 of the resin film is the width of the resin film. They are continuously arranged at the same position in the direction 27. In the filter E25, the position of the repeating unit 28 moves as the resin film travels in the traveling direction 26. However, the regular hexagonal repeating unit 28 has different shapes in the traveling direction 26 of the resin film and the width direction 27 of the resin film. It has become.

  In FIG. 10, the schematic of the example of the repeating unit 28 in this invention is shown. The repeating unit 28 has a circular repeating unit U41, a square repeating unit V42, a cross-shaped repeating unit W43, and a ring-shaped repeating unit T47. Both have the same shape in the resin film running direction 26 and the resin film width direction 27, and defects can be emphasized in the same degree in the resin film running direction 26 and the resin film width direction 27. The defect of the resin film 1 can be detected with high accuracy. Among these, in the circular repeating unit U41 and the ring-shaped repeating unit T47, defects are emphasized in the same degree in all directions, not limited to the two directions of the resin film running direction 26 and the resin film width direction 27. Therefore, the defect of the resin film 1 can be detected particularly accurately.

  FIG. 11 shows a schematic diagram of an example of a repeating unit 28 different from the present invention. The repeating unit 28 has a rectangular repeating unit X44, a triangular repeating unit Y45, and a regular hexagonal repeating unit Z46. In both cases, the resin film running direction 26 and the resin film width direction 27 have different shapes, and defects are emphasized at different degrees in the resin film running direction 26 and the resin film width direction 27. A difference depending on the direction may occur, and a defect in the resin film 1 may not be detected with high accuracy.

  A schematic diagram of a specific film production method of the present invention is shown in FIG. The present invention is not limited to this.

  In the case of a film manufacturing method using a thermoplastic resin as a raw material, the raw material resin pellets are supplied to an extruder 11 as an extrusion means, melted in a temperature range from the melting point to plus 70 ° C., weighed with a gear pump, and then filtered with a filtration device. The molten resin is filtered to remove foreign matters and gelled products. Next, the resin melt that has passed through the filtering device is formed into a target width and thickness by a die 12 that is a die means, and then continuously discharged as a certain amount of sheet-like melt. Next, an electrostatic charge is deposited on the extruded sheet-like melt from the upper surface or the lower surface, and is cooled in close contact with a rotating cooling body 13 (also called a casting drum) as a cooling means in a temperature range of 10 ° C. to 60 ° C. Solidified to obtain an unstretched resin film 1. As a film casting method, air is blown out from a slit-like, spot-like, or planar air supply device (also called an air chamber), and is brought into close contact with the rotating cooling body to be cooled and solidified. A method of closely contacting and cooling and solidifying is also preferable. Next, biaxial stretching of the unstretched resin film 1 is performed using a stretching apparatus. Here, in general, as a biaxial stretching method for improving the physical strength by imparting molecular orientation to the film, the unstretched film is run in the film stretching direction (conveying direction) with the longitudinal stretching machine 14. In other words, after stretching in the longitudinal direction, a uniaxially stretched film stretched in the longitudinal direction is sequentially biaxially stretched in the width direction of the film perpendicular to the running direction, that is, in the transverse direction, by a transverse stretching machine 15 (also called a stenter). And a simultaneous biaxial stretching method in which an unstretched film is stretched simultaneously in a longitudinal direction and a lateral direction of a film in a stenter are known.

  As an example of the film production method of the present invention, the sequential biaxial stretching method will be described. Using the longitudinal stretching machine 14, the unstretched resin film 1 is stretched in the film traveling direction (conveying direction), that is, in the longitudinal direction. Stretching in the running direction refers to stretching for imparting molecular orientation in the running direction of the film, and is usually performed by a difference in roll peripheral speed, and this stretching may be performed in one step, You may carry out in multiple steps using a roll pair. As the draw ratio of the resin film 1, 2 to 8 times is preferably used. The stretching temperature is preferably a temperature range of plus 90 ° C. from the glass transition temperature of the resin constituting the film. The thus obtained uniaxially stretched resin film 1 is subjected to surface treatment such as corona treatment, flame treatment, and plasma treatment as necessary, and then, such as easy slipping, easy adhesion, and antistatic properties. You may provide a function by apply | coating a coating liquid with the coating device which is an application means in a film manufacturing process.

  Next, the resin film 1 uniaxially stretched in the longitudinal direction is preheated in a stenter preheating chamber using a stenter, and stretched in the width direction of the film perpendicular to the running direction, that is, in the transverse direction, in the stenter stretching chamber. Stretching in the width direction refers to stretching for imparting molecular orientation in the width direction of the film, from the entrance portion of the stenter to the exit portion along the rails located at both end portions in the width direction of the film in the stenter. A number of clips moving toward the film are conveyed while gripping both side edges in the width direction of the film, and stretched in the width direction of the film. As the draw ratio of the resin film 1, 2 to 8 times is preferably used. The stretching temperature is preferably a temperature range of plus 90 ° C. from the glass transition temperature of the resin constituting the film. The biaxially stretched resin film 1 is heat-treated in a temperature range of 150 ° C. to 250 ° C. in a stenter heat fixing chamber in order to impart flatness and dimensional stability. After being heat-treated in this manner, it is cooled to room temperature while being uniformly cooled in the width direction in the stenter cooling chamber, and taken up by a winder 17 as a winding means to obtain a biaxially stretched resin film 1. Moreover, you may use a relaxation process etc. together in the case of cooling from heat processing as needed.

  The installation position of the film inspection machine 16 in the present invention is preferably installed between the rotary cooling body 13 that is the cooling means in the film manufacturing process described above and the winder 17 that is the winding means. When an unstretched film is produced, the above installation position is preferable. Moreover, when manufacturing a biaxially stretched film, it is the same installation position. Specifically, in the sequential biaxial stretching method, it is installed between the transverse stretching machine 15 and the winder 17 shown in FIG. Is preferred.

  The film manufacturing method of this invention can obtain the resin film of the outstanding film quality without a crack, a foreign material, etc. by having the process of test | inspecting a resin film using the film inspection method of this invention.

  EXAMPLES Hereinafter, although this invention is demonstrated along an Example, this invention is not restrict | limited by these Examples. Various characteristics were measured by the following methods.

(Detection of defects in resin film)
Using the standard sample 31 for defect detection evaluation of the resin film 1 shown in FIG. 9, the defect is detected by moving the standard sample 31 in the traveling direction 26 of the resin film at a traveling speed of 60 m / min in front of the lens 5. We verified whether it was possible. Light source 3 (manufacturer: Keyence Corporation, product number: CA-DBW50H), area sensor camera 4 (manufacturer: Keyence Corporation, product number: CA-H2100C), lens 5 (manufacturer: Keyence Corporation, product number: CA-LHE50), And the data processing device 6 (manufacturer: Keyence Corporation, product number: CV-X290F), the light is projected from the light source 3 of the light projecting means toward the resin film 1, and the transmitted light 7 transmitted through the resin film 1 or The reflected light 8 reflected from the surface of the resin film was taken into the area sensor camera 4 from the lens 5, and the detection data was processed by the data processing device 6.

  The standard sample 31 shown in FIG. 9 has three types of scratches in the same direction as the major axis as defects of the resin film 1. The major axis of the scratch is about 100 μm (= 0.1 mm) with a large scratch 32 and 33 within the scratch. About 50 μm (= 0.05 mm), and the small scratch 34 is about 10 μm (= 0.01 mm).

  In the evaluation method, the standard sample 31 is moved in front of the lens 5 at a running speed of 60 m / min in the running direction 26 of the resin film, and this is repeated 10 times. At this time, the standard sample 31 is shifted in the width direction 27 of the resin film by 0.1 mm for each run. 10 out of 10 detections were marked as ◯, 10 out of 4 or more and 9 or less detections were Δ, and 3 or less out of 10 detections were marked with ×.

Example 1
In the film inspection method according to the transmission method of the present invention shown in FIG. 1, the repeating unit 28 of the repeating pattern shown in FIG. 5 is square in the filter 2 portion, and the position of the repeating unit 28 advances in the running direction 26 of the resin film. A filter B22 was used that moved with time.

  The repeating pattern of the filter B22 is a 3 mm square and is repeatedly arranged at a pitch of 3.2 mm in the width direction 27 of the resin film. Also, the resin film travel direction 26 is repeatedly arranged at a pitch of 3.2 mm, but the second line moves 1.6 mm in the resin film width direction 27 with respect to the first line (1/2 of the turn-back pitch). doing. Furthermore, the third row moves 1.6 mm with respect to the second row, and as a result, is the same as the first row.

  The standard sample 31 is moved in the running direction 26 of the resin film at a running speed of 60 m / min by the film inspection method according to the transmission method of the invention shown in FIG. Repeated 10 times. Next, the film was inspected in the same manner as described above with the standard sample 31 shown in FIG. 9 as a horizontal flaw rotated by 90 ° with respect to the running direction 26 of the resin film. Next, film inspection was performed in the same manner as described above, with the standard sample 31 shown in FIG. 9 as an oblique scratch rotated by 45 ° with respect to the running direction 26 of the resin film.

  The results are shown in Table 1. In the case of a vertical flaw and a horizontal flaw, all flaws could be detected 10 times. In the case of diagonal scratches, the small scratch 34 could not be detected twice in 10 times.

(Example 2)
In the film inspection method according to the transmission method of the present invention shown in FIG. 1, the repeating unit 28 of the repeating pattern shown in FIG. 4 is circular in the filter 2 portion, and the position of the repeating unit 28 advances in the running direction 26 of the resin film. Filter A21 was used that moved as

  In the repeating pattern of the filter A21, circles having a diameter of 3 mm are repeatedly arranged at a pitch of 3.2 mm in the width direction 27 of the resin film. Also, the resin film travel direction 26 is repeatedly arranged at a pitch of 3.2 mm, but the second line moves 1.6 mm in the resin film width direction 27 with respect to the first line (1/2 of the turn-back pitch). doing. Furthermore, the third row moves 1.6 mm with respect to the second row, and as a result, is the same as the first row. A film inspection was conducted in the same manner as in Example 1 except that the filter was used.

 The results are shown in Table 1. In the case of the vertical scratch, the case of the horizontal scratch, and the case of the diagonal scratch, all the scratches could be detected 10 times.

(Example 3)
In the film inspection method according to the reflection system of the present invention shown in FIG. 2, the repeating unit 28 of the repeating pattern shown in FIG. 4 is circular in the filter 2 portion, and the position of the repeating unit 28 advances in the running direction 26 of the resin film. Filter A21 was used that moved as A film inspection was performed in the same manner as in Example 1 except that the film inspection method and the filter were used.

  The results are shown in Table 1. In the case of the vertical scratch, the case of the horizontal scratch, and the case of the diagonal scratch, all the scratches could be detected 10 times.

Example 4
In the film inspection method according to the transmission method of the present invention shown in FIG. 1, the repeating unit 28 of the repeating pattern shown in FIG. 6 has a cross shape in the filter 2, and the position of the repeating unit 28 is in the running direction 26 of the resin film. Filter C23 was used that moved as it progressed.

  The repetitive pattern of the filter C23 is a cruciform shape in which four corners are cut out by 0.75 mm each from a 3 mm square (two rectangles having a long side of 3 mm and a short side of 1.5 mm are orthogonal to each other at an angle of 90 °. Are overlapped in the width direction 27 of the resin film at a pitch of 3.2 mm. Further, the resin film is repeatedly arranged in the running direction 26 at a pitch of 2.45 mm, but the second row moves 1.6 mm in the resin film width direction 27 with respect to the first row (1/2 of the turn-back pitch). doing. Furthermore, the third row moves 1.6 mm with respect to the second row, and as a result, is the same as the first row. A film inspection was conducted in the same manner as in Example 1 except that the filter was used.

  The results are shown in Table 1. In the case of a vertical flaw and a horizontal flaw, all flaws could be detected 10 times. In the case of diagonal scratches, the small scratch 34 could not be detected 3 times out of 10 times.

(Example 5)
In the film inspection method according to the transmission method of the present invention shown in FIG. 1, the repeating unit 28 of the repeating pattern shown in FIG. 12 is ring-shaped in the filter 2 portion, and the position of the repeating unit 28 is in the running direction 26 of the resin film. A filter F48 was used that moved as it progressed.

  The repetitive pattern of the filter F48 is a ring shape formed by a region surrounded by a circular outer peripheral portion having a diameter of 3 mm and a circular outer peripheral portion having a diameter of 1 mm formed in the circular shape having a diameter of 3 mm. 27 is repeatedly arranged at a pitch of 3.2 mm. Also, the resin film travel direction 26 is repeatedly arranged at a pitch of 3.2 mm, but the second line moves 1.6 mm in the resin film width direction 27 with respect to the first line (1/2 of the turn-back pitch). doing. Furthermore, the third row moves 1.6 mm with respect to the second row, and as a result, is the same as the first row. A film inspection was conducted in the same manner as in Example 1 except that the filter was used.

  The results are shown in Table 1. In the case of the vertical scratch, the case of the horizontal scratch, and the case of the diagonal scratch, all the scratches could be detected 10 times.

(Example 6)
In the film inspection method according to the reflection system of the present invention shown in FIG. 2, the repeating unit 28 of the repeating pattern shown in FIG. 12 is ring-shaped in the filter 2 portion, and the position of the repeating unit 28 is in the running direction 26 of the resin film. A filter F48 was used that moved as it progressed. That is, the film inspection was performed in the same manner as in Example 5 except that the film inspection method was used.

  The results are shown in Table 1. In the case of the vertical scratch, the case of the horizontal scratch, and the case of the diagonal scratch, all the scratches could be detected 10 times.

(Comparative Example 1)
In the film inspection method by the transmission method of the present invention shown in FIG. 1, the repeating unit 28 of the repeating pattern shown in FIG. 7 is square in the filter 2 portion, and the position of the repeating unit 28 advances in the running direction 26 of the resin film. Filter D24 was used which did not move as

  The repeating pattern of the filter D24 is a 3 mm square and is repeatedly arranged at a pitch of 3.2 mm in the width direction 27 of the resin film. Further, the resin film travel direction 26 is also repeatedly arranged at a pitch of 3.2 mm. A film inspection was conducted in the same manner as in Example 1 except that the filter was used.

  The results are shown in Table 1. In the case of vertical scratches, there were cases where scratches were hidden behind the pattern boundary line (width 0.2 mm) following the resin film running direction 26 of the filter D24 regardless of the size of the scratches (detection during 10 times). Number of completed scratches: 32: 9 scratches, 33: 8 scratches, 34: 6 scratches). In the case of a horizontal flaw, as in the case of a vertical flaw, regardless of the size of the flaw, the flaw may be hidden behind the pattern boundary line (width 0.2 mm) following the resin film running direction 26 of the filter D24 and cannot be detected. (Number of times of detection in 10 times, large scratch 32: 9, small scratch 33: 9, small scratch 34: 4). In the case of diagonal scratches, as with vertical and horizontal scratches, regardless of the size of the scratches, scratches are hidden on the pattern boundary line (width 0.2 mm) following the resin film running direction 26 of the filter D24 and cannot be detected. (The number of times of detection in 10 times, large scratch 32: 6, small scratch 33: 5, small scratch 34: 3).

(Comparative Example 2)
In the film inspection method according to the transmission method of the present invention shown in FIG. 1, the repeating unit 28 of the repeating pattern shown in FIG. 8 is a regular hexagon in the filter 2 portion, that is, the repeating unit 28 is the resin film running direction 26 and the resin film. A filter E25 having a shape different from that of the width direction 27 and moving as the position of the repeating unit 28 advances in the running direction 26 of the resin film was used.

  The repeating pattern of the filter E25 is a 3 mm square regular hexagon and is repeatedly arranged at a pitch of 3.2 mm in the width direction 27 of the resin film. Further, the resin film travel direction 26 is also repeatedly arranged at a pitch of 2.34 mm, but the second row moves 1.6 mm (1/2 of the turn-back pitch) in the width direction 27 of the resin film with respect to the first row. doing. Furthermore, the third row moves 1.6 mm with respect to the second row, and as a result, is the same as the first row. A film inspection was conducted in the same manner as in Example 1 except that the filter was used.

  The results are shown in Table 1. Since the filter E25 having a regular hexagonal repeating unit 28 has a boundary line parallel to the running direction 26 of the resin film, the horizontal scratch is sufficiently emphasized, but there is no boundary line parallel to the width direction 27 of the resin film. The vertical scratches are insufficiently emphasized. In the case of a vertical flaw, the large flaw 32 could be detected, but there were cases where the flaw 33 and the small flaw 34 could not be detected (the number of detections in ten times, the large flaw 32:10 times, the flaw 33: 8). Times, scratches 34: 2 times). In the case of horizontal flaws, all flaws could be detected all 10 times regardless of the size of the flaw. In the case of diagonal scratches, large scratches 32 and small scratches 33 could be detected, but small scratches could not be detected (number of times of detection in 10 times, large scratches 32:10 times, scratches 33:10 times) , Small scratch 34: 8 times).

  According to the present invention, there are provided a film inspection method capable of accurately detecting defects in a resin film, and a film manufacturing method capable of obtaining a resin film having excellent film quality, comprising a step of inspecting a resin film using the film inspection method. Can do. For example, it is preferably used as a film inspection method for various optical films such as liquid crystal display components such as liquid crystal polarizing plates and retardation plates, PDP members, touch panel members, laminated glass members, and film production methods using the same. Can do.

1: Resin film 2: Filter 3: Light source (light projection means)
4: Area sensor camera 5: Lens 6: Data processing device 7: Transmitted light 8: Reflected light 11: Extruder 12: Base 13: Rotating cooling body 14: Longitudinal stretching machine 15: Horizontal stretching machine 16: Film inspection machine 17: Winder 21: Filter A
22: Filter B
23: Filter C
24: Filter D
25: Filter E
26: Running direction of resin film 27: Width direction of resin film 28: Repeat unit 31: Standard sample 32: Large scratch 33: Scratch 34: Small scratch 41: Repeat unit U (circular)
42: Repeating unit V (square)
43: Repeat unit W (cross)
44: Repeat unit X (rectangular)
45: Repeat unit Y (triangle)
46: Repeating unit Z (regular hexagon)
47: Repeating unit T (ring type)
48: Filter F

Claims (5)

A film inspection method for detecting a defect in a resin film by projecting light from a light projecting means toward the resin film and taking in transmitted light transmitted through the resin film or reflected light reflected from the surface of the resin film into an area sensor camera Because
A filter in which a light-blocking repetitive pattern is formed on a transparent material or a light-blocking material is used to form a repetitive pattern at a position where the projection light from the light projecting unit passes between the light projecting unit and the resin film. Placed the filter,
The position of the repeating unit of the repeating pattern is moving as it proceeds in the traveling direction of the resin film,
The film inspection method, wherein the shape of the repeating unit is the same shape even if the running direction of the resin film and the width direction of the resin film are interchanged.   The film inspection method according to claim 1, wherein a repeating unit of the repeating pattern is circular.   The film inspection method according to claim 1, wherein the light shielding material is a metal.   The film inspection method according to claim 1, wherein the filter is a filter in which a light-shielding repeating pattern is formed on a transparent material, and a repeating unit of the repeating pattern is a ring shape.   The film manufacturing method which has the process of test | inspecting a resin film using the film inspection method in any one of Claims 1-4.

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