Inspection apparatus, inspection method, and film manufacturing method

Abstract

The invention provides an inspection device, an inspection method and a film manufacturing method which are suitable for planar inspection of the peripheral surface of a film. The inspection device (10) is provided with: a light source (30) that irradiates a circumferential surface of a film (11) with linear illumination light that is long in the width direction of a film (12); a region sensor (32) that continuously captures an image of a region that is long in the width direction of the film (12) and includes the irradiation range of the illumination light; and a detection unit (34) that detects irregularities on the peripheral surface of the film (11) using a temporal change in the shape of the reflected light of the illumination light captured by the area sensor (32).

Description

Technical Field

[0001] The present invention relates to an inspection device, an inspection method, and a film manufacturing method, wherein the inspection device inspects the circumference of a film roll that rotates about an axis as it is transported along with a strip of film. Background Technology

[0002] Patent Document 1 describes an inspection device comprising a light source that illuminates a linear illumination beam onto an object to be inspected, and a camera that captures images of a range including the illumination beam. In this inspection device, the light source and the camera are slid relative to the object to be inspected while continuously capturing images, and the angle (relative to the camera) of the surface of the object to be inspected (the reflection point of the illumination beam) is detected.

[0003] Previous technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2016-200396 Summary of the Invention

[0004] The technical problem to be solved by the invention However, in the aforementioned patent document 1, although the slope of the reflection point itself can be detected, it is difficult to grasp the correlation or continuity between the reflection point and adjacent parts, which makes it unsuitable for surface detection (detection of small concavities and convexities).

[0005] The present invention was made in view of the above background, and its object is to provide an inspection apparatus, inspection method, and film manufacturing method suitable for inspecting the surface appearance (surface appearance of film on the periphery of the film roll) of a film roll as an object to be inspected.

[0006] means for solving technical problems To achieve the above objectives, the inspection apparatus of the present invention inspects the circumferential surface of a roll of film rotating about an axis as it is transported along with a strip of film. The inspection apparatus includes: a light source that illuminates the circumferential surface of the roll with a linear illumination light that is long in the width direction of the film; a region sensor that continuously captures images of a region long in the width direction of the film, including the illumination range of the illumination light; and a detection unit that detects the unevenness of the circumferential surface of the roll by using the time change of the shape of the reflected light from the illumination light captured by the region sensor.

[0007] The detection unit can segment the photographic image captured by the area sensor into multiple images that are elongated along the film transport direction, extract the location of maximum brightness from each image, and use the time change of the location of the maximum brightness location along the transport direction to detect the concavity and convexity.

[0008] An image that is long in the film transport direction is formed by arranging the imaging range of one pixel of the area sensor along the transport direction. In the extraction of the maximum brightness position, the detection unit sets the imaging range of the maximum brightness in the imaging range of one pixel as the target range, calculates the brightness centroid point in the target range using the brightness of the imaging range adjacent to the target range in the transport direction, and extracts the brightness centroid point as the maximum brightness position.

[0009] The film width is between 0.2m and 3m, and the area sensor can be a digital camera positioned between 1m and 3m from the film roll, including the total width of the film within the photographic area.

[0010] The detection unit can use the time change of the position of the maximum brightness position in the conveying direction to detect the shape and size of the concavity and convexity in the conveying direction.

[0011] The inspection department can use the shape of the bumps and dents in the conveying direction to determine the type of bumps and dents.

[0012] The inspection unit can detect the size of the unevenness in the width direction by comparing the time change of the position of the maximum brightness in the transport direction along the width direction of the film.

[0013] The inspection department can determine the type of protrusion by using the ratio of the size of the protrusion in the conveying direction to the size of the protrusion in the width direction.

[0014] It may include an image forming unit that forms an inspection image on a planar view of the outer periphery of the unfolded film, displaying a raised or recessed image.

[0015] Furthermore, in order to achieve the above objectives, the inspection method of the present invention inspects the circumferential surface of a film roll that rotates about an axis while being transported along with a strip of film. The inspection method includes: an illumination step, illuminating the circumferential surface of the film roll with a linear illumination light that is long in the width direction of the film; a photographic step, continuously photographing a region long in the width direction of the film including the illumination range of the illumination light; and an inspection step, using the time change of the shape of the reflected light from the illumination light photographed in the photographic step to detect the unevenness of the circumferential surface of the film roll.

[0016] Furthermore, in order to achieve the above objectives, the film manufacturing method of the present invention includes: a film manufacturing step, forming a strip of film and feeding it out in the form of a roll of film wound on a core; and a film transport step, after the film is wound out from the roll of film, winding it out again in the form of a roll of film, the film transport step including: an illumination step, irradiating the periphery of the roll with a linear illumination light that is long in the width direction of the film; a photography step, continuously photographing a region long in the width direction of the film including the illumination range of the illumination light; and an inspection step, detecting the unevenness of the periphery of the roll of film by using the time change of the shape of the reflected light of the illumination light photographed in the photography step.

[0017] Invention Effects According to the present invention, an inspection apparatus, an inspection method, and a film manufacturing method suitable for planar inspection of the circumference of a film roll can be provided. Attached Figure Description

[0018] Figure 1 This is an explanatory diagram of the inspection device.

[0019] Figure 2 This is an explanatory diagram showing the state of the photographic image input from the area sensor.

[0020] Figure 3 This is an explanatory diagram showing the state of segmented photographic images.

[0021] Figure 4 This is an explanatory diagram used to illustrate the extraction order of the location of maximum brightness.

[0022] Figure 5 It is an explanatory diagram showing the line segment that is detected as the shape of reflected light.

[0023] Figure 6 This is an explanatory diagram used to illustrate the displacement of the position of maximum brightness.

[0024] Figure 7 This is an explanatory diagram used to illustrate the displacement of the position of maximum brightness.

[0025] Figure 8 This is an explanatory diagram used to illustrate the displacement of the position of maximum brightness.

[0026] Figure 9 This is a flowchart showing the inspection sequence for defects.

[0027] Figure 10 This is an explanatory diagram of the inspection device.

[0028] Figure 11 This is an image representing an example of an image being inspected.

[0029] Figure 12 This is an image representing an example of an image being inspected.

[0030] Figure 13 This is an explanatory diagram showing an example of the thickness distribution along the width direction of the film.

[0031] Figure 14 This is an explanatory diagram showing an example of the thickness distribution along the width direction of the film. Detailed Implementation

[0032] [First Implementation] like Figure 1 As shown, the inspection device 10 of the present invention is a device for inspecting the peripheral surface of the film roll 11 (the surface of the film sheet 12 on the peripheral surface of the film roll 11). The inspection device 10 is provided in the film transport process 14 of transporting the film sheet 12.

[0033] The film transport process 14 includes a roll-out machine 20 and a take-up machine 24. The film 12 is a long strip with a width between 0.2m and 3m. The film 12 is fed from the previous process (film manufacturing process) in the form of a roll 11 wound on a core and placed in the roll-out machine 20. The roll 11 in the roll-out machine 20 rotates around the axis of the core. Thus, the film 12 is wound out from the roll 11. The film 12 wound out from the roll 11 is transported to the take-up machine 24 via conveyor rollers 26 and 28. The film 12 transported to the take-up machine 24 is wound onto the core rotating around the axis in the take-up machine 24, and is once again in the form of a roll 11.

[0034] The inspection device 10 includes a light source 30, a region sensor 32, and a detection unit 34. In this embodiment, an example is described where the inspection device 10 is placed near the winding machine 20 to inspect the surface of the film 12 on the periphery of the film roll 11 that has been wound up. However, it is also possible to configure the inspection device 10 to be placed near the winding machine 24 to inspect the surface of the film 12 on the periphery of the film roll 11 that has been wound up.

[0035] Light source 30 illuminates the periphery of film 11 (the surface of the outermost film 12) with a linear illumination beam along the axial direction (width direction of film 12) of film 11 (illumination step). In this embodiment, light source 30 illuminates a range of film 12 with a width of 2000 mm and a length (width) of 20 mm in the transport direction from a slit-shaped light-emitting portion of film 12 with a width of 3000 mm and a length (width) of 20 mm in the transport direction. Furthermore, in this embodiment, the incident angle of the illumination light from light source 30 (the angle formed by the normal N of the outer periphery of film 11 at the point where the illumination axis L1 of the illumination light from light source 30 intersects with the outer periphery of film 11 (the center position of the illumination range) and the illumination axis L1) is set to 5 degrees. Moreover, in this embodiment, the illuminance at the center position of the illumination range when illuminated is at least 5 times the illuminance when the illumination light is not applied.

[0036] Furthermore, the specifications of the light source 30 (specifications of the light-emitting part, illumination range of the illumination light, illumination angle (incident angle), and luminous intensity) are not limited to the above example and can be appropriately varied. Specifically, the illumination light from the light source 30 preferably illuminates the entire width of the film 12 in the width direction. Furthermore, the illumination light from the light source 30 preferably illuminates the film 12 in the transport direction of its length (width) within a range of 1 to 50 mm. Moreover, the incident angle is preferably in the range of 5 degrees to 45 degrees. Furthermore, the light intensity of the illumination light emitted from the light source 30, as the illuminance of the observed film surface, is preferably in the range of 500 to 100,000 lux.

[0037] The area sensor 32 is a digital camera, which has multiple photoelectric conversion elements that accumulate charges corresponding to the amount of incident light. These elements correspond to image sensors such as CCD (Charge Coupled Device) or CMOS (Complementary Metal-Oxide Semiconductor) arranged on a two-dimensional plane at the pixel positions. During shooting, the charge accumulated in each pixel (photoelectric conversion element) is output as an image signal. In this embodiment, the area sensor 23 is described as an example of a single digital camera, but the area sensor 23 could also be a sensor that arranges multiple digital cameras along the width of the film 12.

[0038] The area sensor 32 defines a rectangular area within the outer periphery of the film 11, including the center of the illumination area from the light source 30 and its vicinity, that is longer in the width direction and shorter in the transport direction than the width direction of the film 12. This area is then continuously photographed at a predetermined photographic cycle (photographic step). In this embodiment, the area sensor 32 is positioned 1.5m away from the film 11, photographing a range of 2000mm in width direction and 300mm in length (width) in the transport direction of the film 12. Furthermore, in this embodiment, the photographic angle of the area sensor 32 (the angle between the photographic optical axis L2 of the area sensor 32 and the aforementioned normal N) is set to 5 degrees. The photographic cycle of the area sensor 32 is set to 200 times per second.

[0039] Furthermore, the specifications of the area sensor 32 (position, imaging range, imaging angle, imaging cycle, etc.) are not limited to the above example and can be appropriately changed. From the viewpoint of the depth of field of the area sensor, the area sensor 32 is preferably positioned at a point where it separates from the film 11 within a range of 0.5m to 3m. Furthermore, the imaging range of the area sensor 32 preferably covers the entire width of the film 12 in the width direction. Moreover, the imaging range of the area sensor 32 in the film 12 transport direction is preferably within a length (width) range of 10mm to 500mm in the film 12 transport direction. Furthermore, the imaging angle is preferably within a range of 5 degrees to 45 degrees. Furthermore, the imaging cycle is preferably within a range of 30 to 1000 times per second. Furthermore, the imaging cycle does not need to be constant and can be changed according to the film 12 transport speed, the diameter of the film 11, etc. Furthermore, in order to eliminate subject shake, it is preferable to adjust the film 12 transport speed and the shooting cycle. Specifically, it is preferable to set the film 12 transport speed [mm / s] / shooting cycle [f / s] < resolution [mm / pix].

[0040] like Figure 2 As shown, the photographic image 40, illuminated by the aforementioned light source 30 and captured by the area sensor 32, is input to the detection unit 34. The photographic image 40 contains a high-brightness portion 42, which becomes bright due to reflection of the illumination light from the light source 30 onto the peripheral surface of the film 11 (the film 12 on the peripheral surface of the film 11). This photographic image 40 is continuously input to the detection unit 34 as the area sensor 32 captures images continuously.

[0041] If the detection unit 34 receives a photographic image 40 from the area sensor 32, it detects the shape of the reflected light (reflected light from the illumination light from the light source 30) reflected in the input photographic image 40, that is, the shape of the high-brightness portion 42 that becomes high-brightness due to the reflected light.

[0042] In this test, such as Figure 3 As shown, the detection unit 34 first divides the photographic image 40 along the width direction of the film 12, thereby generating multiple segmented images 50 that extend along the transport direction of the film 12. In this embodiment, the detection unit 34 generates the segmented images 50 by dividing the photographic image 40 into a width equal to one pixel of the area sensor 32. That is, in this embodiment, the segmented image 50 is a photographic area 52 (reference area) equal to one pixel of the area sensor 32. Figure 4 Images arranged in the transport direction of film 12 (reference) Figure 4 ).

[0043] Next, as Figure 4 As shown, the detection unit 34 extracts the maximum brightness position 54 from each segmented image 50. In this embodiment, the detection unit 34 sets the maximum image brightness range 52 in the imaging range 52 (the imaging range of one pixel of the area sensor 32) constituting the segmented image 50 as the target range 52sub, calculates the brightness centroid point (brightness centroid point in the transport direction of the film 12) within the target range 52sub using the brightness of the imaging range 52 adjacent to the target range 52sub, and extracts the calculated brightness centroid point as the maximum brightness position 54.

[0044] Specifically, in this embodiment, using the brightness of the upper imaging range 52up and the lower imaging range 52dw of the target range 52sub, a brightness centroid line 54a representing the brightness centroid in the transport direction within the target range 52sub is determined, and the midpoint of the brightness centroid line 54a is extracted as the maximum brightness position 54. For example, when the brightness of the imaging range 52up is 10 and the brightness of the imaging range 52dw is 30, when the length of the transport direction of the target range 52sub is set to 1, the line segment connecting the position 0.75 (0.25 from the lower end) from the upper end of the target range 52sub becomes the brightness centroid line 54a, and the center of this line segment is extracted as the brightness centroid point (i.e., the maximum brightness position 54).

[0045] Thus, by setting the brightness center point within the target range 52sub as the maximum brightness position 54, for example, compared to directly setting the entire target range 52sub as the maximum brightness position 54, a higher precision inspection can be performed. That is, since the maximum brightness position 54 is used for bump detection as described later, if the range of the maximum brightness position 54 widens, the detection precision decreases; if it narrows, the detection precision increases. Furthermore, in this embodiment, the range of the maximum brightness position 54 can be further refined from the target range 52sub (the imaging range of one pixel). Therefore, a higher precision inspection can be performed.

[0046] In particular, when inspecting relatively large objects such as film 12 (film roll 11) using a single area sensor 32, the imaging range 52 of each pixel of the area sensor 32 becomes relatively large, leading to a decrease in inspection accuracy. In contrast, as in this embodiment, by further finely narrowing the range of the maximum brightness position 54 from the imaging range 52 of each pixel, the problem of decreased inspection accuracy can be prevented even when inspecting relatively large objects such as film 12 (film roll 11) using a single area sensor 32.

[0047] like Figure 5 As shown, the detection unit 34 detects the shape of a line segment 60 that is long in the width direction of the film 12 at the maximum brightness position 54 of each segmented image 50 extracted as described above, which is taken as the shape of the high brightness portion 42 in the photographic image 40 (i.e., the shape of reflected light). Furthermore, the detection unit 34 uses the time change of the shape of the high brightness portion 42 (line segment 60) thus detected to detect the unevenness of the peripheral surface of the film 11 (the film 12 on the peripheral surface of the film 11) (detection step).

[0048] In this convexity detection, the detection unit 34 checks the displacement (time change of position) of the maximum brightness position 54 in each segmented image 50. That is, it checks the displacement of the maximum brightness position 54 in the transport direction of the film 12.

[0049] like Figure 6 As shown, when the circumferential surface of film 11 (the film 12 on the circumferential surface of film 11) is smooth, even if film 12 is transported (even if it is moved), the reflection direction of the illumination light will not change, and the maximum brightness position 54 will not shift from the initial position. On the other hand, as Figure 7 , Figure 8 As shown, if there are uneven surfaces on the periphery of the film 11, the direction of reflection of the illumination light will change as the film 12 is transported, and thus the position of maximum brightness 54 will also shift.

[0050] Furthermore, in Figure 7 In this case, until interval A (until interval A reaches the illumination range of the lighting light), the maximum brightness position 54 remains in its initial position without displacement. Within interval A (during the period when interval A is conveyed to the illumination range of the lighting light), the maximum brightness position 54 moves downwards (displacement); in interval B, it moves upwards (displacement); and in interval C, it moves downwards (displacement). After interval C (after interval C has passed the illumination range of the lighting light), the maximum brightness position 54 returns to its initial position without displacement. Furthermore, in Figure 8In this case, the maximum brightness position 54 remains in its initial position without displacement until interval D. In interval D, the maximum brightness position 54 shifts downwards, and in interval E, it moves upwards. After interval E, the maximum brightness position 54 returns to its initial position without displacement.

[0051] The detection unit 34 utilizes this property to detect the location of the unevenness within the illumination light's illumination position, i.e., the location of the unevenness, within the interval from when the maximum brightness position 54 moves from its initial position to when it returns to its initial position. Furthermore, the detection unit 34 detects the shape of the unevenness based on the mode of displacement of the maximum brightness position 54. Moreover, the detection unit 34 detects the size of the unevenness in the film 12's transport direction based on the displacement speed of the maximum brightness position 54 (the time required for the maximum brightness position 54 to move from its initial position and return to its initial position (the number of times the area sensor 32 takes pictures)), the film 12's transport speed, and the area sensor 32's imaging range. Furthermore, the detection unit 34 detects the size of the unevenness in the film 12's width direction by comparing the displacements of the maximum brightness positions 54 of adjacent segmented images 50.

[0052] As described above, the inspection apparatus 10 (inspection method) of the present invention includes: a light source 30 that illuminates the peripheral surface of the film 11 with a linear illumination light that extends along the width direction of the film 12 (illumination step); a region sensor 32 that continuously captures images of a region extending along the width direction of the film 12, including the illumination range of the illumination light (photography step); and a detection unit 34 that detects unevenness on the peripheral surface of the film 11 (inspection step). In the detection step, the detection unit 34 uses the shape of the reflected light from the illumination light, specifically, uses the time variation of the maximum brightness position 54 to detect unevenness. Furthermore, the film manufacturing method of the present invention includes a film manufacturing process and a film transport process. In the film transport process, the aforementioned inspection apparatus 10 (inspection method) is used to perform inspection (detection of unevenness).

[0053] [Second Implementation] In the first embodiment described above, the detection unit 34 detects the position, shape, and size of the protrusions and depressions. However, in the second embodiment, the detection unit 34, in addition to detecting the position, shape, and size of the protrusions and depressions, also determines the type of protrusions and depressions. Furthermore, in the descriptions following the second embodiment, components that are the same as those in the first embodiment are marked with the same symbols and their descriptions are omitted.

[0054] like Figure 9 As shown, the detection unit 34 has a concave-convex shape corresponding to Figure 7If the shape shown (convex shape) and the dimensions of the protrusion / contour in the conveying direction of the film 12 are within the range of 0.5mm to 10mm, and the dimensions of the protrusion / contour in the width direction of the film 12 are within the range of 0.5mm to 10mm, and the aspect ratio of the protrusion / contour (the value obtained by dividing the dimensions of the protrusion / contour in the width direction of the film 12 by the dimensions of the protrusion / contour in the conveying direction of the film 12) is 1.5 or less, then the protrusion / contour is determined to be a "rolling defect". A "rolling defect" refers to a small-sized, particle-like protrusion / contour, which is a defective protrusion / contour that leads to a decrease in product quality.

[0055] On the other hand, the detection unit 34 classifies unevenness that does not meet the above conditions as benign unevenness that does not affect product quality. Examples of such benign unevenness include, for instance, unevenness caused by step differences at the joints of the films 12. This type of unevenness corresponds to... Figure 8 The shape shown is a stepped shape, and the dimensions in the width direction of the film 12 are also relatively large, and the aspect ratio is also greater than 1.5.

[0056] Furthermore, in cases where defective unevenness is detected, such as a "rolling defect," it is preferable to notify the relevant parties. As a notification method, for example, methods such as outputting a warning sound or warning message from a speaker, or displaying a warning message on a display screen, can be considered. Furthermore, the inspection image 72 described in the third embodiment described later (see reference...) Figure 11 , Figure 12 In the text, you can emphasize the display of poor unevenness.

[0057] [Third Implementation] like Figure 10 As shown, in the third embodiment, the inspection apparatus 10 includes an image forming unit 70 in addition to the aforementioned components. For example... Figure 11 , Figure 12 As shown, the image forming unit 70 forms an inspection image 72, which displays the unevenness of the peripheral surface of the film 11 detected by the detection unit 34 on a planar view of the unfolded outer periphery of the film 11. Furthermore, Figure 11 Inspection image 72 shows numerous wrinkles and scattered "rolling defects," indicating a suboptimal product quality. On the other hand, Figure 12 Inspection image 72 shows images with few wrinkles and no undesirable bumps, indicating a good product quality.

[0058] Thus, by displaying the unevenness on a planar diagram, the entire periphery of the film 11 can be inspected at a glance, making inspection (detection of defects (undesirable unevenness)) easy. Furthermore, the inspection results using the inspection image 72 thus formed can be easily fed back to the manufacturing or transport process of the film 12; that is, while confirming the inspection image 72, the manufacturing or transport conditions of the film 12 can be changed to achieve a more preferred (preferred in terms of product quality) state.

[0059] For example, to obtain Figure 11 The inspection results of film 12 were obtained by adjusting the manufacturing conditions so that the thickness distribution of film 12 in the width direction became... Figure 13 Manufactured in the state shown. For example... Figure 13 As shown, the film 12 has an average thickness of 40 μm, and the edges of the film 12 are approximately 2% (Δd) thicker than the average thickness. Furthermore, the film 12 minimizes thickness deviation in the central area. However, as... Figure 11 As already explained, it has Figure 13 The film 12 shown in the thickness distribution has sporadic visible defects and unevenness, and is not preferred in terms of product quality.

[0060] on the other hand, Figure 12 By adjusting the manufacturing conditions, the thickness distribution in the width direction of the film 12 is made into... Figure 14 Manufactured in the state shown. For example... Figure 14 As shown, the film 12 and Figure 13 Similarly, with the average thickness set to 40 μm, the edge of film 12 is set to be approximately 2% (Δd) thicker than the average thickness. On the other hand, with... Figure 13 In comparison, the thickness deviation is relatively large across the total width of film 12. Furthermore, in terms of... Figure 14 In the film 12 with the thickness distribution shown, the following was obtained Figure 12 The inspection result shown indicates that there are no defects or unevenness and that the product quality is good. Thus, regarding the thickness distribution, which greatly affects the winding quality of the film, in situations where the quality of the wound film cannot be readily predicted using indicators such as thickness deviation, or where numerous experiments with varying thickness patterns are required for prediction, the present invention allows for visual inspection of the entire film roll to assess winding quality. Furthermore, according to the present invention, the inspection (detection of defects (undesirable unevenness)) or inspection results can be easily fed back to the manufacturing or transport process of the film 12, which helps improve product quality.

[0061] Symbol Explanation 10-Inspection device, 11-Film roll, 12-Film sheet, 14-Transportation process, 20-Roller, 24-Roller, 26, 28-Transport rollers, 30-Light source, 32-Area sensor, 34-Detection unit, 40-Photographed image, 42-High brightness section, 50-Segmented image, 52-Photographing range (the photographing range of one pixel of the area sensor), 52sub-Target range (the photographing range with the highest brightness), 52up-Photographing range (the photographing range above the target range), 52dw-Photographing range (the photographing range below the target range), 54-Maximum brightness position, 54a-Brightness centroid line, 60-Line segment (the line segment detected as the shape of reflected light), 70-Image forming unit, 72-Inspection image, A~E-Interval, L1-Illumination optical axis, L2-Photographing optical axis, N-Normal.

Claims

1. An inspection device for inspecting the circumferential surface of a roll of film rotating about an axis during the transport of a strip of film, said inspection device comprising: A light source that illuminates the periphery of the film with a long linear illumination beam along the width of the film; A region sensor continuously captures images of a region extending along the width direction of the film, including the area illuminated by the illumination light. and The detection unit uses the time-varying shape of the reflected light from the illumination light captured by the area sensor to detect the unevenness of the film's circumference.

2. The inspection device according to claim 1, wherein, The detection unit segments the photographic image captured by the area sensor into multiple images that are elongated along the film transport direction, extracts the position of maximum brightness from each image, and uses the time change of the position of the maximum brightness position along the transport direction to detect the unevenness.

3. The inspection device according to claim 2, wherein, An image that is long in the film transport direction is formed by arranging the photographic range of one pixel of the area sensor along the transport direction. In the extraction of the maximum brightness position, the detection unit sets the maximum brightness imaging range within the imaging range of one pixel as the target range, uses the brightness of the imaging range adjacent to the target range in the conveying direction to calculate the brightness centroid point within the target range, and extracts the brightness centroid point as the maximum brightness position.

4. The inspection device according to claim 3, wherein, The width of the film is between 0.2m and 3m. The area sensor is a digital camera positioned between 1m and 3m from the film roll, and includes the total width of the film within the photographic range.

5. The inspection device according to claim 2, wherein, The detection unit uses the time change of the position of the maximum brightness position in the conveying direction to detect the shape and size of the concave and convex shapes in the conveying direction.

6. The inspection device according to claim 5, wherein, The detection unit uses the shape of the protrusions and concavities in the conveying direction to determine the type of protrusions and concavities.

7. The inspection apparatus according to claim 5 or 6, wherein, The detection unit detects the size of the unevenness in the width direction by comparing the time change of the position of maximum brightness in the transport direction in the width direction of the film.

8. The inspection device according to claim 7, wherein, The detection unit uses the ratio of the size of the protrusion in the conveying direction to the size of the protrusion in the width direction to determine the type of the protrusion.

9. The inspection apparatus according to claim 8, comprising: An image forming unit forms an inspection image on a planar view of the outer periphery of the unfolded film, displaying the concave and convex features.

10. An inspection method for inspecting the circumferential surface of a film roll rotating about an axis during the transport of a strip of film, the inspection method comprising: The illumination step involves irradiating the periphery of the film with a long linear illumination light along the width direction of the film. The photographic procedure involves continuously photographing a region extending along the width direction of the film, including the area illuminated by the illumination light. and The inspection step uses the temporal change in the shape of the reflected light from the illumination light captured in the photographic step to detect the unevenness of the film's circumference.

11. A method for manufacturing film, comprising: The film manufacturing process forms long strips of film, which are then fed out as rolls wound on a core. and The film transport process involves winding the film again from the film roll after it has been unwound from the film roll. The film transport process includes: The illumination step involves irradiating the periphery of the film with a long linear illumination light along the width direction of the film. The photographic steps include continuously photographing a region extending along the width direction of the film, encompassing the area illuminated by the illumination light; and The inspection step uses the temporal change in the shape of the reflected light from the illumination light captured in the photographic step to detect the unevenness of the film's circumference.

Images