JP2010085209A - Film inspection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film inspection device capable of detecting accurately a defect generated on a film during manufacture. <P>SOLUTION: This inspection device 10 is equipped with a light irradiation device 16 for irradiating a film 12 with each light L1, L2, and forming regularly reflected light; and a sensor 18 for detecting a defect. Light bands 22 are generated on the film 12, and the sensor 18 uses a dark part 24 therebetween as a detection domain. Though a light receiving amount by the sensor 18 is small normally, when scattered light is generated by a defect, the light receiving amount is increased, to thereby detect the defect. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a film inspection apparatus for inspecting defects generated during film production.

  Single or multilayer films are used for various applications. Defects such as pinholes, fish eyes and cracks occur due to various factors during film production. For example, the pinhole 32a is a defect in which the coating layer 38 laminated on the base film 36 is missing (FIG. 12). Allowable values such as the number and size of defects are provided depending on the type of film and intended use. Therefore, it is necessary to inspect defects during the production of the film and determine the quality of the produced film.

  For example, the following Patent Document 1 discloses a film inspection apparatus. This inspection apparatus irradiates the film which came on a roll with strip | belt-shaped light, and detects the reflected light of a light with a sensor. Since the film has a curved surface on the roll, the brightness of the band of light decreases as it moves away from the central axis. A light shielding mask is disposed between the light irradiation device and the sheet, and only the side of the light band is irradiated onto the film. The film is irradiated only with light with reduced brightness, and the reflected light is detected by a sensor. If light is scattered by a defect, the defect appears as a dark part. Since the brightness of light is low, halation is unlikely to occur, and defect detection failure due to halation is reduced.

  However, since the brightness of the light is small, the difference between the reflected light and the dark part due to the defect is small. Increasing the sensitivity of the sensor to increase the difference increases noise. Therefore, there is a possibility that the defect cannot be detected accurately. In particular, there is a case where detection of a minute defect is required due to enhancement of the function of the film, and the device of Patent Document 1 may not be able to accurately detect a minute defect.

  Patent Document 2 discloses an inspection apparatus that irradiates a laminate film with light from two light sources and receives reflected light. The light receiving element receives specularly reflected light. If there is a defect, the light receiving element scatters and cannot receive the specularly reflected light, resulting in a dark part.

  However, halation may occur when light is scattered, and the difference between the specularly reflected light and the dark portion is reduced. It is difficult to detect the dark part, and there is a risk of missing a defect.

  Further, all of the devices of Patent Documents 3 to 5 detect line defects and detect defects by receiving regular reflection light with a sensor. As in Patent Documents 1 and 2, halation may occur.

JP 2006-208184 A (FIGS. 4 and 5) JP 2007-205921 A (FIG. 1) Japanese Patent No. 3210846 (FIG. 1, claim 1) Japanese Patent No. 3668307 (FIG. 1, claim 1) JP-A-6-26839 (FIG. 1, 0012)

  The objective of this invention is providing the film inspection apparatus which can detect the defect which arose in the film at the time of manufacture with a sufficient precision.

  The film inspection apparatus includes a light irradiation device that irradiates light on a film and forms two light bands on the film, and a sensor that uses a dark portion formed between the light bands as a light receiving region.

  The film is irradiated with light from a light irradiation device. Two bands of light are formed, and a dark portion between the bands is a light receiving region of the sensor. The sensor also receives scattered light generated by the film defect.

  The said light irradiation apparatus is provided between the light source and the said light source and a film, and is provided with the light-shielding plate which has two strip | belt-shaped light transmission parts. Moreover, you may provide two linear light sources as another light irradiation apparatus.

  The sensor is a line sensor in which light receiving elements are arranged in the width direction of the film, the means for differentiating the value of the amount of light received by the sensor along the width direction of the film, and the value obtained by the differentiation in advance Means for determining a defect when the threshold value is higher than the stored threshold value.

  An inspection roller that contacts the film and rotates in synchronization with the moving speed of the film is provided, and the light irradiation device forms a band of light in the width direction of the film with respect to the film that is in close contact with the inspection roller. Further, the inspection roller may be subjected to a light absorption process on the surface.

  Two guide rollers rotating in synchronization with the moving speed of the film are provided with the film in close contact, and the light irradiation device forms a light band in the width direction of the film with respect to the film moving between the guide rollers. You may do it.

  Two of the film inspection apparatuses described above may be provided, one film inspection apparatus may be inspected for defects on one side of the film, and the other film inspection apparatus may be inspected for defects on the other side of the film.

  In the present invention, normally, a sensor uses a dark part as an inspection region, and detects scattered light due to a defect. Therefore, the sensor does not receive the halation caused by the film defect with the bright part as the light receiving area. The difference in the amount of received light between the normal part of the film and the defect can be increased, and the defect detection accuracy is good. Further, since a bright spot due to scattered light is generated in the dark part, the defect can be recognized well even if it is actually confirmed with the naked eye, and it is easy to manufacture and adjust the apparatus.

  The film inspection apparatus of this invention is demonstrated using drawing. The drawings are shown schematically and may differ from the actual scale of the apparatus.

  The film inspection apparatus is an apparatus that performs inspection during the production of a film. Examples of the film to be inspected include a multilayer film in which a coating layer is formed on a base film, a laminated film in which a metal foil such as a copper foil is bonded, and the like is a homogeneous film without a pattern. In the figure, the coating layer and the like are omitted. In the present invention, it is possible to inspect defects that cause light scattering when irradiated with light. Examples of the defects include pinholes generated in the coating layer, fish eyes and cracks generated on the film surface, and a portion where the material is not dissolved well during production and solidified inside the film.

  An inspection apparatus 10 shown in FIG. 1 includes an inspection roller 14 for transporting a light-transmitting film 12, a light irradiation apparatus 16 that generates regular reflection light by irradiating the film 12 with light L1 and L2, and a defect. And a sensor 18 for detection.

  The inspection roller 14 is brought into close contact with the film 12 in order to convey the film 12 and rotates in synchronization with the moving speed of the film 12. The inspection surface of the film 12 is disposed on the opposite side of the inspection roller 14. A guide roller 20 is provided to bring the film 12 into close contact with the inspection roller 14. In FIG. 1, the film 12 is conveyed while meandering up and down by the guide roller 20. Since the film 12 is brought into close contact with the inspection roller 14, fluttering of the film 12 is eliminated, and an accurate inspection can be performed.

  The surface of the inspection roller 14 is subjected to light absorption processing. The light absorption rate is 90% or more, preferably 95 to 98%. An example of light absorption is black matting treatment, and the surface roughness is set to 2 s or more, preferably 4 s to 10 s, for the black matting treatment. Further, as the surface material of the inspection roller 14, light absorption treatment may be performed using phos black II, black chrome, copper oxide black, black nickel, black alumite, or the like. The light absorption process reduces noise to the sensor 18 so that a defective portion can be accurately detected.

  The diameter of the inspection roller 14 is about 50 to 180 mm. This is because if the diameter is too small, the band of light spreads too much due to the curve of the surface of the inspection roller 14.

  The light irradiation device 16 irradiates the film 12 that is in close contact with the inspection roller 14 with light L1 and L2. When the film 12 is irradiated with the lights L1 and L2, regular reflection light is generated on the film 12, and a band 22 of light is formed (FIG. 2A). There are two light bands 22 arranged in parallel. The width of the light band 22 is 2 mm or less, preferably 0.3 to 1.5 mm. The width of the dark part 24 formed between the light bands 22 is 2 mm or less, preferably 0.5 to 1.0 mm. Since the surface of the inspection roller 14 is a curved surface, there is a change in the amount of light in the light band 22 (FIG. 2B).

  While the film 12 is conveyed, the light irradiation device 16 irradiates the film 12 with the light L1 and L2. The defective portion generated in the film 12 generates scattered light when irradiated with light. The scattered light is received by the sensor 18.

  The sensor 18 can receive the scattered light of the lights L1 and L2 emitted from the light irradiation device 16 only when there is a defect portion generated in the film 12. As an example of the light receiving sensitivity, the light receiving sensitivity of the sensor 18 is about 2400 V / lx · sec. In addition, as an adaptive range that can be detected using scattered light of a defective portion generated in the film 12, the light receiving sensitivity of the sensor 18 is about 1000 to 4000 V / lx · sec.

  The light irradiation device 16 includes a light source 26 that emits light, and a light shielding plate 28 between the light source 26 and the film 12. The light source 26 is not particularly limited, but it is necessary that the lights L1 and L2 do not spread toward the film 12 and go straight.

  The light shielding plate 28 includes two strip-shaped light transmission portions 30 (FIG. 3). The surface of the light shielding plate 28 is preferably subjected to the same light absorption treatment as that of the inspection roller 14 so as not to cause unnecessary light irregular reflection. The light shielding plate 28 may be attached to the light source 26 (FIG. 4A), or may be in the space between the light source 26 and the film 12 (FIG. 4B). Lights L1 and L2 that have passed through the light transmission part 30 are irradiated onto the film 12, and other light is shielded. Unnecessary light is not irradiated onto the film 12 at all, and the sensor 18 can be prevented from being erroneously detected.

  4A, the distance between the film 12 and the light shielding plate 28 is about 50 to 200 mm, and the distance between the light shielding plate 28 and the light source 26 is about 10 to 30 mm. In FIG. 4A, the light shielding plate 28 is directly attached to the light source 26. However, there is an interval from the portion of the light source 26 that actually emits light to the light shielding plate 28, and the above distance is the interval. In the light shielding plate 28, the width of the light transmission part 30 is about 10 mm, and the light shielding part 31 between the light transmission parts 30 is about 10 mm. In FIG. 4B, the distance between the film 12 and the light shielding plate 28 is about 50 to 200 mm, and the distance between the light shielding plate 28 and the light source 26 is appropriately set.

  Moreover, you may provide the two light sources 26 as another light irradiation apparatus 16 (FIG.4 (c)). The light source 26 emits light in a line shape. In order to emit light in a line shape, each light source 26 includes a plurality of LEDs arranged in a single line shape. Since the LED is packaged with a lens-shaped resin, it is preferable in terms of directivity and light quantity of the lights L1 and L2. If a high-frequency fluorescent tube is used instead of an LED, it is used with a directivity of light with a lens or the like. A cover that covers the light source 26 may be provided, and desired light may be emitted from a slit in the cover.

  In FIG. 4C, the distance between the film 12 and the light source 26 is about 100 to 600 mm, and the lights L1 and L2 are emitted from a slit of about 2 to 20 mm. The distance between the central axes of the lights L1 and L2 is about 25 mm.

  If the film 12 is light transmissive, the portions that are not irradiated with the light L1 and L2 are blackened by the light absorption processing of the inspection roller 14. A black dark portion 24 is formed between the light bands 22. The sensor 16 sets the dark portion 24 as a light receiving area. The light receiving axis L3 of the sensor 18 intersects the central axis of the dark part 24. The regular reflection light of the film 12 is not received by the sensor 18. An example of the sensor 18 is a line sensor in which light receiving elements such as photodiodes are arranged in a line. The light receiving elements are arranged in the width direction of the film 12.

  The sensor 18 receives light at a constant period, is converted into digital data according to the received light quantity, and is processed by the computer 34. Usually, since the sensor 18 has the dark portion 24 as a light receiving region, the light receiving amount of the light receiving element is 0 or a value close to 0 as shown in FIG. The configuration is such that noise is hardly received by the light absorption processing of the inspection roller 14. Further, if the film 12 has a defect, the light amount of the light receiving element that receives the scattered light from the defect increases (FIG. 5B).

  The principle that the sensor 18 receives scattered light will be described. If there is no defect in the film 12, regular reflection light L4, L5 does not reach the sensor 18, as shown in FIG. If the film 12 has a defect 32 such as a pinhole, when the film 12 moves and the defect 32 is irradiated with light, scattered light is generated. For example, as shown in FIG. 7, when one of the lights L1 is irradiated onto the defect 32 to generate scattered light L6, the sensor 18 receives light.

  Further, as shown in FIG. 8, when both of the lights L1 and L2 are irradiated onto the defect 32 to generate scattered light L6 and L7, more scattered light is received than in FIG. 7, and the received light quantity increases. Therefore, when the film 12 moves, the amount of light received by any light receiving element is maximized at the time when the center of the defect 32 passes through the dark part. This is shown in the graph of FIG. The sensor 18 can obtain large scattered lights L6 and L7 by the two light bands 22, and can increase the difference from the normal part.

  Since the above light receiving state changes depending on the size of the defect 32 or the like, the width of the light band 22 and the width of the dark portion 24 are appropriately determined according to the size of the minimum defect 32 to be detected. When the center of the defect 32 comes to the center of the dark portion 24, both ends of the defect 32 are made to enter the light band 22, respectively.

  As described above, the scattered light L6 and L7 having a large amount of light enters the dark portion 24 having a very small amount of light. Since the inspection roller 14 is subjected to a light absorption process, the sensor 18 is less susceptible to noise. Even if the defects 32 are irradiated with the lights L1 and L2 to cause halation, the halation is not affected by the conventional halation because the halation deviates from the light receiving axis L3 of the sensor 18. Therefore, the detection accuracy of the defect 32 can be increased. Since the bright spot in the dark part 24 is detected, it can be easily confirmed with the naked eye, and the device 10 can be easily manufactured and adjusted.

  The light quantity value detected by the sensor 18 is converted into digital data, and the computer 34 determines the defect. For this purpose, means for converting the light quantity value into digital data, means for differentiating the light quantity value of the light received by the sensor 18 along the width direction of the film 12, and the value obtained by the differentiation are stored in advance. The computer 34 is operated as means for determining a defect when it is higher than the threshold value. These means are realized by hardware, software, or both. The defect is determined using a relative value by differentiation, not an absolute value of the light amount. Even if the film 12 is changed, the setting of the apparatus 10 is easy. The differentiation is to differentiate the graph of FIG.

  When the defect 32 is detected, a signal may be sent to the warning lamp to turn on the warning lamp. The computer 34 may specify the position of the defect from the transfer speed of the film 12, the light receiving period of the sensor 18, etc., and display the position on the monitor 36.

  As shown in FIG. 10, an inspection apparatus in which two inspection rollers 14 are provided between the guide rollers 20 may be used. By passing the film 12, one surface of the film 14 is inspected when the film 14 passes through one inspection roller 14, and the other surface of the film 12 is inspected when the film 12 passes through the other inspection roller 14. That is, both surfaces of the film 12 can be inspected. The computer 34 and the monitor 36 may be integrated into one unit, and the light reception values from both sensors 18 may be received by the single computer 34 and the above-described processing may be performed.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to said embodiment. The numerical value shown as an example can be appropriately changed according to the inspection purpose.

  If the film 12 is an opaque film 12 such as a laminated film on which a metal foil such as a copper foil is bonded, the light absorption treatment of the inspection roller 14 may be omitted. The dark portion 24 where no light is irradiated is a light receiving region of the sensor 18, and noise is very small with respect to scattered light received by the sensor 18. The sensor 18 is difficult to detect erroneously. According to the present invention, not only the light-transmitting film 12 but also an opaque film 12 can be handled.

  The film inspection apparatus 10 in FIG. 1 irradiates the light L1 and L2 on the film 12 when it is in close contact with the inspection roller 14. However, if the film 12 is opaque, the inspection roller 14 may be omitted. . Like the film inspection apparatus 10b shown in FIG. 11, when the film 12 moves between the guide rollers 20, light L1, L2 is irradiated. The light irradiation device 16 can form two bands 22 of light in the width direction of the film 12 as in FIG. The film 12 is pressed (adhered) to the guide roller 20. The fluttering of the film 12 can be suppressed by reducing the distance between the guide rollers 20. For example, the interval between the guide rollers 20 is set to about 100 to 500 mm.

  Even the film inspection apparatus 10b of FIG. 11 may have two units as shown in FIG. One inspection device 10b inspects one surface of the film 12, and the other inspection device 10b inspects the other surface of the film 12.

  In addition to moving the film 12, the film 12 may be fixed and the light irradiation device 16 and the sensor 18 may be moved. The light irradiation device 16 and the sensor 18 move with a constant interval. Not only the roll-shaped film 12 but also the sheet film 12 can be inspected.

  As described above, in any of the embodiments, the two bands 22 of light are formed on the film 12, and the dark portion 24 is used as the light receiving region of the sensor 18. Since there is no influence of halation that has been used in the past and the difference between scattered light and noise is large, accurate inspection is possible.

  In addition, the present invention can be carried out in a mode in which various improvements, modifications, and changes are added based on the knowledge of those skilled in the art without departing from the gist thereof.

It is a figure which shows the structure of the film inspection apparatus of this invention which irradiates light to the film closely_contact | adhered to the test | inspection roller. It is a figure of the light belt | band | zone produced by irradiating light to the film on a test | inspection roller, (a) is a figure which shows a mode that two light bands produced | generated in parallel, (b) shows light quantity. FIG. It is a figure which shows a light-shielding plate. It is a figure which shows a light irradiation apparatus, (a) is the figure which attached the light-shielding plate to the housing | casing which comprises a light source, (b) is the figure which provided the light-shielding plate between the light source and the film, (c ) Is a diagram in which two light sources are provided. It is a figure which shows the light quantity which the sensor received, (a) respond | corresponds to the normal part of a film, (b) is a figure corresponding to the position with a defect of a film. It is a figure which shows the mode of light reception when light is irradiated to the normal part of a film, (a) is a general view, (b) is an enlarged view of sensor vicinity. It is a figure which shows the mode of light reception when light is irradiated to the defect of a film, (a) is a general view, (b) is an enlarged view of sensor vicinity. It is a figure which shows the mode of light reception when light is irradiated to the defect of a film, (a) is a general view, (b) is an enlarged view of sensor vicinity. It is a figure which shows the time change of the received light quantity of the arbitrary light receiving elements in a sensor. It is a figure which shows the film inspection apparatus provided with the two film inspection apparatuses of FIG. It is a figure which shows the structure of the film inspection apparatus of this invention which irradiates light to the film which moves between guide rollers. It is a figure which shows the defect of a pinhole.

Explanation of symbols

10, 10b, 11: Film inspection device 12: Film 14: Inspection roller 16: Light irradiation device 18: Sensor 20: Guide roller 22: Light band 24: Dark portion 26 between light bands 26: Light source 28: Light shielding plate 30 : Light transmission part 31: Light shielding part 32: Defect 34: Computer 36: Monitor 36: Base film 38: Coating layers L 1 and L 2: Irradiation light L 3: Light receiving axes L 4 and L 5: Regular reflection light L 6 and L 7: Scattered light

Claims (8)

To inspect the film,
A light irradiation device for irradiating the film with light and forming two bands of light on the film;
A sensor having a dark area formed between the bands of light as a light receiving region;
With
A film inspection apparatus in which a sensor receives scattered light generated by a defect in the film. The light irradiation device is
A light source;
A light-shielding plate disposed between the light source and the film and having two strip-shaped light transmission parts;
The film inspection apparatus of Claim 1 provided with. The film inspection apparatus according to claim 1, wherein the light irradiation device includes two linear light sources. The sensor is a line sensor in which light receiving elements are arranged in the width direction of the film, and means for differentiating the value of the amount of light received by the sensor along the width direction of the film;
Means for determining a defect when a value obtained by the differentiation is higher than a threshold value stored in advance;
The film inspection apparatus according to claim 1, comprising: Adhering the film, provided with an inspection roller that rotates in synchronization with the moving speed of the film,
The film inspection apparatus according to claim 1, wherein the light irradiation device forms a band of light in the width direction of the film with respect to the film in close contact with the inspection roller. The film inspection apparatus according to claim 5, wherein the inspection roller has a surface subjected to light absorption treatment. The film is in close contact, and includes two guide rollers that rotate in synchronization with the moving speed of the film,
The film inspection apparatus according to claim 1, wherein the light irradiation device forms a band of light in the width direction of the film with respect to the film moving between the guide rollers. A film inspection apparatus comprising two film inspection apparatuses according to any one of claims 1 to 7, wherein one film inspection apparatus inspects defects on one surface of the film, and the other film inspection apparatus inspects defects on the other surface of the film. .

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