JP2016045194A - Optical film inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical film inspection device that can precisely detect various different types of defects.SOLUTION: The present invention relates to an optical film inspection device including a light source emitting light from one side of a film to be transferred and an imaging device imaging the film. The optical film inspection device can easily detect various types of defects only with one light source or imaging device since one light source or imaging device alone can easily observe the defects and obtain images taken under different imaging conditions because of overlap of a light irradiation region of the film and an imaged region of the film.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical film inspection apparatus.

  Various optical films such as a polarizer, a TAC, a retardation film, and the like are used for the image display device. Along with the evolution of image display devices, high quality is also required for optical films used therefor.

  However, when manufacturing an optical film, defects occur for various reasons. For example, when foreign matters are mixed in the resin composition forming the optical film, bubbles are generated when the resin composition is cured, foreign materials are mixed in between layers when forming the multilayer structure film, scratches are formed on the film surface. When it occurs, there are various factors such as when the film warps.

  Defects of various shapes are caused by various factors that cause such defects. For example, when foreign matter is inserted or bubbles are generated, irregularities on the surface of the optical film are generated at the corresponding locations, and when scratches are generated, linear defects are generated on the film surface.

  After the production of the optical film is completed, a step of detecting a defect is provided in order to remove a portion where such a defect has occurred. As one of the methods for detecting defects, there is used a method in which the surface of an optical film is photographed with a photographing device and the image is analyzed.

  However, the imaging conditions under which defects of various shapes are easily observed are not the same. Therefore, in order to detect defects of various shapes with high accuracy, it is necessary to set various imaging conditions. For this reason, a plurality of light sources and cameras must be provided, which causes space and economy problems. .

  Although Korean Patent No. 1082699 discloses an optical film inspection apparatus, there is a problem that a plurality of light sources and cameras are required even in the corresponding system.

Korean Registered Patent No. 1082699

  An object of the present invention is to provide an optical film inspection apparatus capable of detecting various defects with high accuracy without requiring a plurality of light sources and imaging devices.

  An object of the present invention is to provide such an optical film inspection method.

  1. A light source for irradiating light from one side of the film to be transferred and an imaging device for imaging the film, and a light irradiation area of the film irradiated with the light and a part of an imaging area of the film to be imaged An optical film inspection device.

  2. 2. The optical film inspection apparatus according to item 1, wherein the light source and the imaging device are separated from each other in a film transport direction.

  3. In the item 1, the optical film inspection device in which the light irradiation direction of the light source and the imaging direction of the imaging device are parallel.

  4). In the item 1, an optical film inspection apparatus in which the light irradiation direction of the light source and the imaging direction of the imaging apparatus are not parallel.

  5. In the item 1, the imaging area is divided into two or more sub-imaging areas having different illuminance ranges according to the transport direction of the film, and the entire image of the film is acquired for each sub-imaging area. A periodic signal generation unit that emits an imaging periodic signal, and the imaging periodic signal from the periodic signal generation unit is received, the imaging signal is transferred to the imaging apparatus for each imaging period, and the captured image received from the imaging apparatus An optical film inspection apparatus further comprising a control unit that detects a defect.

  6). In the item 5, the sub imaging regions have the same width, and the periodic signal generator emits the imaging periodic signal every time the film is moved by the width of the sub imaging region. Optical film inspection device.

  7). In the item 5, the control unit acquires the entire image of the film for each sub imaging area by combining the captured images received from the sub imaging areas for each sub imaging area. An optical film inspection apparatus for detecting the defect.

  8). In the item 1, the light irradiation area includes an effective area of an optical film, and the light source is a light source that irradiates the light so as to have the same illuminance in the width direction of the film in the effective area. Film inspection device.

  9. In the item 5, the optical film inspection apparatus, wherein the defect is a foreign matter defect, an uneven defect, or a scratch defect.

  10. In the item 9, the foreign matter defect is a black defect having a horizontal and vertical length of 30 μm or more in a region having an illuminance difference of 10 gray or more from a normal region around the defect, Among the areas where the illuminance difference from the surrounding normal area is 10 gray or more, the horizontal and vertical lengths are black and white defects each of 30 μm or more, and the scratch defect is the normal area of the periphery In the optical film inspection apparatus, the width is 30 μm or more and the length is three times or more of the width in the region where the illuminance difference is 10 gray or more.

  11. In a method for detecting a defect of an optical film by irradiating light from a light source on one side of a film to be transferred and imaging the film with an imaging device, the light irradiation area of the film irradiated with the light and the image are captured A method for inspecting an optical film, wherein a part of an imaging region of the film overlaps.

  12 12. The optical film inspection method according to item 11, wherein the light source and the imaging device are arranged so as to be separated from each other in a transport direction of the film.

  13. In the item 11, the optical film inspection method, wherein the light irradiation direction of the light source and the imaging direction of the imaging device are arranged in parallel.

  14 In the item 11, the optical film inspection method is arranged such that the light irradiation direction of the light source and the imaging direction of the imaging device are non-parallel.

  15. In the item 11, the imaging region is divided into two or more sub-imaging regions having different illuminance ranges according to the transport direction of the film, and the film is transported by the width of the sub-imaging region. An optical film inspection method in which a film is imaged and an entire image of the film is acquired for each sub-imaging region.

  16. In the item 11, the optical film inspection method of acquiring the entire image of the film for each of the sub imaging regions by combining the captured images received from the sub imaging regions for each of the sub imaging regions.

  The optical film inspection apparatus of the present invention can easily observe each defect with only one light source and an imaging device, and can acquire images taken under various imaging conditions. In addition, various defects can be easily detected without an imaging device.

FIG. 1 is a diagram schematically illustrating an optical film inspection apparatus according to an embodiment of the present invention. FIG. 2 is a top view of a light source and an imaging device in an optical film inspection apparatus according to an embodiment of the present invention. FIG. 3 is a specific example of adjusting the light irradiation angle of the light source and the imaging angle of the imaging device. FIG. 4 is a specific example of adjusting the light irradiation angle of the light source and the imaging angle of the imaging device. FIG. 5 is an image obtained by imaging the same defect in different imaging regions (bright field (a), gray field (b), dark field (c)) in the optical film inspection apparatus according to an embodiment of the present invention. . FIG. 6 is an image obtained by imaging the same defect in different imaging regions (bright field (a), gray field (b), dark field (c)) in the optical film inspection apparatus according to an embodiment of the present invention. . FIG. 7 is an image obtained by imaging the same defect in different imaging regions (bright field (a), gray field (b), dark field (c)) in the optical film inspection apparatus according to an embodiment of the present invention. . FIG. 8 illustrates a case where the imaging area is divided into three sub imaging areas having different illuminance ranges according to the film transfer direction. FIG. 9 is a diagram schematically illustrating a method for acquiring an entire film image from images acquired in the respective sub imaging regions.

  The present invention includes a light source that irradiates light from one side of a film to be transferred, and an imaging device that images the film, and a light irradiation area of the film that is irradiated with light and an imaging area of the film that is imaged Since a part of each overlaps, each defect can be easily observed with only one light source and imaging device, and images taken under various imaging conditions can be obtained. The present invention relates to an optical film inspection apparatus that can easily detect various defects without an apparatus.

  Hereinafter, the present invention will be described in detail.

  The optical film inspection device of the present invention includes a light source and an imaging device. FIG. 1 schematically shows an optical film inspection apparatus according to an embodiment of the present invention.

  The optical film 10 to be inspected is not particularly limited as long as it is an optical system and can be inspected. Specific examples of the optical film 10 include, but are not limited to, a polarizer, a transparent protective film, a polarizing plate having a protective film attached to at least one surface of the polarizer, a retardation film, and the like. is not.

  The optical film 10 is generally provided by a roll-to-roll method, but a roll-shaped film may cause damage such as elongation of the end of the roll due to storage, transportation, handling, or the like. Therefore, when using it as a product, you may cut | disconnect the terminal part of the width direction and use the remaining part, without using the whole length of the width direction.

  The remaining portion to be used can be said to be an effective area of the optical film 10. The length of the end portion to be cut is not particularly limited, and may be appropriately selected depending on the desired product performance, product handling condition, and the like.

  In the present invention, light irradiation and imaging described later of the optical film 10 may be performed on the entire area or the effective area of the optical film 10, and the light irradiation area and the imaging area may include an effective area.

  The light source 100 irradiates the film 10 with light from one side of the film 10 to be transferred, specifically, from one side (the lower surface in FIG. 1) with respect to the surface of the film 10.

  The light irradiation angle is not particularly limited as long as the film 10 can be irradiated with light. Hereinafter, although the case where light is irradiated to a film perpendicularly is demonstrated by a specific example, it is not restrict | limited to these.

  According to an embodiment of the present invention, the light source 100 may be a light source 100 that emits light so as to have the same illuminance in the width direction of the film 10 in the light irradiation region 110 of the film 10. As described above, the light irradiation area 110 may include an effective area of the film. Specifically, only the effective area of the film 10 in the light irradiation area 110 has the same illuminance in the width direction. Although you may irradiate light, it is not restrict | limited to these.

  In the present invention, the same illuminance includes not only completely the same illuminance but also substantially the same illuminance. Substantially the same illuminance means that the difference cannot be recognized by the inspection apparatus, in other words, the illuminance deviation is ± 10%, ± 5%, ± 1%, ± 0.1%, ± 0 Examples include 0.01%, ± 0.0001%, and ± 0.00001%, but are not limited thereto. Therefore, the light source 100 has a long side or short side having a length greater than or equal to the width of the film, or in the case of the regular square light source 100, one side or more may have a length greater than or equal to the film width. Good. In that case, since the difference in illuminance in the width direction of the film does not occur, it is easy to distinguish it from a sub imaging region described later.

  The imaging device 200 images the surface of the film 10 and images the film from the same side as the light source 100 or from the other side of the film 10 (upper surface in FIG. 1).

  Similarly, the imaging angle is not particularly limited as long as the imaging apparatus 200 can also capture the film 10. Hereinafter, although the case where the film 10 is imaged vertically will be described using a specific example, the present invention is not limited to this.

  In the present invention, a light irradiation area of the film 10 irradiated with light and a part of an imaging area of the film to be imaged overlap.

  A method of implementing the regions to overlap each other is not particularly limited, and for example, the light source 100 and the imaging device 200 may be implemented so as to be separated from each other in the transport direction of the film 10. .

  FIG. 1 is a view schematically showing an optical film inspection apparatus of the present invention according to such a specific example, and FIG. 2 is a top view of a light source 100 and an imaging apparatus 200 in the optical film inspection apparatus. As shown in FIGS. 1 and 2, the light source 100 and the imaging device 200 are separated from each other in the film transfer direction, and the light irradiation area 110 of the film to be irradiated with light and the imaging area 210 of the film to be imaged. Some overlap.

  Further, as shown in FIGS. 3 and 4, it can be realized by adjusting the light irradiation angle and the imaging angle. Therefore, the light source 100 and the imaging device 200 may be arranged so that the light irradiation direction and the imaging direction are not parallel. FIG. 3 is a diagram showing one specific example, and the light irradiation direction and the imaging direction are not parallel to each other, and the light irradiation area 110 and the imaging area 210 may be partially overlapped. Good.

  Of course, by adjusting the light irradiation angle and the imaging angle, as shown in FIG. 4, one of the light irradiation area and the imaging area of the film to be imaged in a state where the light irradiation direction and the imaging direction are parallel to each other. It is also possible for the parts to overlap.

  In this way, the imaging region 210 of the film 10 to be imaged depends on the film transfer direction by overlapping the light irradiation region of the film 10 irradiated with light and a part of the imaging region of the film to be imaged. An illuminance difference occurs.

  Therefore, the optical film inspection apparatus of the present invention divides the imaging area 210 into two or more sub imaging areas 210a, 210b, and 210c having different illuminance ranges according to the film transfer direction, and the sub imaging areas 210a and 210b. , 210c is obtained for each of the images of the entire film 10, and defects are detected based on the images.

  The defect that is the detection target of the present invention is roughly classified into a foreign substance defect, an uneven defect, and a scratch defect.

  As shown in FIG. 5A, the foreign matter defect means a defect that appears as a black dot, and has a horizontal and vertical length of a region having an illuminance difference of 10 gray or more from the surrounding normal region. Each black spot-like defect of 30 μm or more can be classified as a foreign matter defect.

  As shown in FIG. 6B, the irregular defect means a defect in which black and white appear together, and the horizontal and vertical lengths of the areas where the illuminance difference from the surrounding normal area is 10 gray or more. However, black and white defects of 30 μm or more can be classified as uneven defects.

  As shown in FIG. 7 (c), the scratch defect means a long and thin line defect, and in a region where the illuminance difference from the surrounding normal region is 10 gray or more, the width is 30 μm or more and the length is Defects that are three or more times wide can be classified as scratch defects.

  In the case of these defects, the observation conditions under which the defects can be easily observed are different. 5 to 7, (a), (b), and (c) are photographs in which the same part of the film is captured in different sub imaging regions, and (a) is the first sub imaging region (Bright (field, bright field) and (b) are photographs taken in the second sub imaging area (Gray field), and (c) are photographs taken in the third sub imaging area (Dark field).

  Specifically, the foreign substance defect in FIG. 5 is easily observed in the first sub-imaging area (Bright field), and can be observed in the second sub-imaging area (Gray field), but the third sub-imaging area. It is difficult to observe in the dark field. 6 is easily observed in the second sub imaging region (Gray field), but is observed in the first sub imaging region (Bright field) and the third sub imaging region (Dark field). Is difficult. 7 is easily observed in the third sub-imaging area (Dark field), but is observed in the first sub-imaging area (Bright field) and the second sub-imaging area (Gray field). Is difficult.

  That is, in order to detect all of these defects with high accuracy, it is necessary to set imaging conditions suitable for each defect, and thus a plurality of imaging devices and light sources are required.

  However, since the optical film inspection apparatus of the present invention obtains an image of the entire film for each of the sub-imaging regions 210a, 210b, and 210c and detects defects based on the images, the optical film inspection apparatus is various even with only one light source 100 and the imaging apparatus 200. Various types of defects can be detected with high accuracy.

  FIG. 8 illustrates a case where the imaging area 210 is divided into three sub imaging areas 210a, 210b, and 210c having different illuminance ranges according to the film transfer direction. Thus, the imaging area 210 can be divided into two or more sub imaging areas 210a, 210b, and 210c having different illuminance (gray) ranges.

  The illumination intensity that divides each of the sub imaging regions 210a, 210b, and 210c is not particularly limited, and desired product performance, inspection level, luminous intensity of the light source 100, distance between the light source 100 and the film 10, the light source 100 and the imaging device 200. The distance between the image pickup apparatus 200 and the film 10 may be adjusted in various ways.

  The sub imaging area may be divided according to the extent to which the light irradiation area of the film and the imaging area of the film overlap.

  Specifically, the light irradiation area of the film may be divided into a main irradiation area indicating the illuminance to be embodied by the light source 100 and a sub-irradiation area that is not.

  If the imaging area 210 is divided into two sub-imaging areas, the imaging area 210 can be divided into a part overlapping the main irradiation area and a part overlapping the sub-irradiation area.

  If the imaging area 210 is divided into three sub-imaging areas, a portion of the imaging area 210 that overlaps the main irradiation area is defined as a first sub-imaging area (Bright field; 210a), and the sub-irradiation area is defined as 2 Dividing into two regions, a portion of the imaging region 210 that overlaps the first sub-irradiation region, which is a region where scattered light and diffused light reach more, is scattered into the second sub-imaging region (Gray field; 210b). A portion overlapping the second sub-irradiation region, which is a portion where light and diffused light reach less, can be divided into a third sub-imaging region (Dark field; 210c).

  For example, the first sub imaging region (Bright field; 210a) is 90 gray to 150 gray or less, and the second sub imaging region (Gray field; 210b) is 30 gray to less than 90 gray, the third sub The imaging field (Dark field; 210c) may be an area having an illuminance of less than 30 gray, but is not limited thereto.

  The optical film inspection apparatus of the present invention further includes a periodic signal generation unit 300 and a control unit 400 in order to acquire an image of the entire film for each of the sub imaging regions 210a, 210b, and 210c and detect defects based on the images. .

  The periodic signal generating unit 300 generates an imaging periodic signal so as to acquire an image of the entire film for each of the sub imaging regions 210a, 210b, and 210c.

  Specifically, each of the sub imaging regions 210a, 210b, and 210c has the same width, and the periodic signal generating unit 300 moves the film by the width of the sub imaging regions 210a, 210b, and 210c. An imaging periodic signal is emitted. And the control part 400 receives an imaging period signal from the said periodic signal generation part 300, and transfers an imaging signal to the said imaging device 200 for every imaging period.

  The widths of the sub imaging areas 210a, 210b, and 210c are related to the imaging cycle, and may be appropriately selected within the imaging area.

  If the film is imaged every time the film is transferred by the width of the sub imaging areas 210a, 210b, and 210c, the entire film transferred for each of the sub imaging areas 210a, 210b, and 210c is eventually imaged.

  The control unit 400 combines the captured images received from the sub-imaging regions 210a, 210b, and 210c separately for the sub-imaging regions 210a, 210b, and 210c, so that the entire film image is obtained for each of the sub-imaging regions 210a, 210b, and 210c. And detecting a defect based on that.

  FIG. 9 schematically shows a method for acquiring an entire film image. As shown in FIG. 9, the imaging area 210 is divided into three sub imaging areas 210a, 210b, and 210c, and the film is imaged every time the film 10 is transferred by the width of the sub imaging areas 210a, 210b, and 210c. By summing up the entire captured images, it is possible to obtain images in which the entire transferred film 10 is captured in all of the first sub-region 210a, the second sub-region 210b, and the third sub-region 210c.

  Then, when only the images picked up in the first sub-region 210a are connected, an image in which the entire film is picked up in the first sub-region 210a can be obtained as shown in FIG. 9A. Similarly, an image (FIG. 9B) in which the entire film is imaged in the second sub-region 210b by joining the images imaged in the second sub-region 210b is imaged in the third sub-region 210c. The images (FIG. 9C) in which the entire film is imaged in the third sub-region 210c can be obtained by stitching together the images.

  As described above, when the entire film image is acquired for each of the sub imaging regions 210a, 210b, and 210c, there are specific defects that are easily observed for each image, and therefore various types of defects can be easily detected. .

  The present invention also provides an optical film inspection method.

  The optical film inspection method of the present invention is a method for irradiating light from one side of a film to be transferred, imaging the film, and detecting defects in the optical film, wherein the film is irradiated with light. The area and a part of the imaging area of the film to be imaged are overlapped.

  A method for realizing the overlapping of the regions is not particularly limited. For example, the light source 100 and the imaging device 200 may be arranged so as to be separated from each other in the transport direction of the film 10, or the light irradiation angle and It can also be realized by adjusting the imaging angle. Therefore, the light source 100 and the imaging device 200 may be arranged so that the light irradiation direction and the imaging direction are not parallel. Of course, it is also possible to adjust the light irradiation angle and the imaging angle so that the light irradiation area and the imaging area of the film to be imaged partially overlap with each other in a state where the light irradiation direction and the imaging direction are parallel. It is.

  By causing the light irradiation area of the film 10 and a part of the imaging area of the film 10 to be imaged to overlap, an illuminance difference occurs in the imaging area of the film to be imaged according to the film transfer direction.

  Therefore, according to the optical film inspection method of the present invention, the imaging area is divided into two or more sub imaging areas having different illuminance ranges according to the film transfer direction, and an image of the entire film is obtained for each sub imaging area. Based on this, a defect is detected.

  The film is imaged every time the film is transferred by the width of the sub imaging area, and an image of the entire film can be acquired for each sub imaging area.

  Then, by combining the captured images received from the respective sub image capturing areas for each sub image capturing area, an entire film image can be acquired for each sub image capturing area as shown in FIG.

  As described above, when an entire film image is acquired for each sub imaging region, there are specific defects that are easily observed for each image, and therefore various types of defects can be easily detected.

  Hereinafter, preferred embodiments are shown to assist in understanding the present invention, but these embodiments are merely illustrative of the present invention and do not limit the scope of the appended claims. It will be apparent to those skilled in the art that various changes and modifications can be made to the embodiments within the scope of the technical idea, and such changes and modifications are within the scope of the appended claims. Of course it belongs.

EXAMPLE Using a Testo 545 LuxMeter, a light source having an illuminance of 200,000 lux measured at a location 1 mm away from the illumination surface was used to irradiate the film with light vertically from a distance of 1 cm from the transported polarizing film. In the light irradiation region of the film, the illuminance difference in the film width direction was not measured.

  Then, on the other side of the optical film, the film was vertically imaged with an Area scan camera (Balser acA2000-340 km) from a distance of 12 cm. The distance between the light source and the camera was 13 cm.

  Depending on the direction of film transport, the imaging area of the camera was divided into a bright field, a gray field, and a dark field based on illuminance. At that time, the image illuminance of each region was 90 gray to 150 gray in the bright field, 30 gray to less than 90 gray in the gray field, and 0 gray to less than 30 gray in the dark field.

  Thereafter, each time the film is moved by the width of the sub-imaging area, an image is taken, and photographs taken in the bright field, gray field, and dark field for the same observed foreign matter defect are shown in FIG. Similarly, it is shown in FIG. 6 for the irregularity defect, and also for the scratch defect in FIG.

  Referring to FIGS. 5 to 7, it can be confirmed that foreign matter defects are easily observed in the bright field, uneven defects in the gray field, and scratch defects are easily observed in the dark field.

  Conventionally, in order to detect all of these defects, it has been necessary to provide three light sources and cameras, that is, three optical systems. However, the present invention detects all of these defects with one system. can do.

Claims (16)

A light source that emits light from one side of the film to be transported, and an imaging device that images the film,
An optical film inspection apparatus, wherein a light irradiation region of the film irradiated with the light and a part of an imaging region of the film to be imaged overlap.   The optical film inspection apparatus according to claim 1, wherein the light source and the imaging device are separated from each other in a transport direction of the film.   The optical film inspection apparatus according to claim 1, wherein a light irradiation direction of the light source and an imaging direction of the imaging apparatus are parallel.   The optical film inspection apparatus according to claim 1, wherein a light irradiation direction of the light source and an imaging direction of the imaging apparatus are not parallel. The imaging area is divided into two or more sub-imaging areas having different illuminance ranges depending on the film transfer direction,
A periodic signal generator that emits an imaging periodic signal so as to obtain an entire image of the film for each of the sub imaging regions;
A control unit that receives the imaging periodic signal from the periodic signal generation unit, transfers the imaging signal to the imaging apparatus for each imaging period, and detects a defect from the captured image received from the imaging apparatus; The optical film inspection apparatus according to claim 1. Each of the sub imaging regions has the same width as each other,
The optical film inspection apparatus according to claim 5, wherein the periodic signal generator emits the imaging periodic signal every time the film is moved by the width of the sub imaging area.   The control unit acquires the entire image of the film in each sub imaging area by combining the captured images received from the sub imaging areas for each sub imaging area, and detects the defect based thereon. The optical film inspection apparatus according to claim 5 or 6. The light irradiation area includes an effective area of the optical film,
The optical film inspection apparatus according to claim 1, wherein the light source is a light source that irradiates the light so as to have the same illuminance in the width direction of the film in the effective region.   The optical film inspection apparatus according to claim 5, wherein the defect is a foreign matter defect, an uneven defect, or a scratch defect. The foreign matter defect is a black defect having a horizontal and vertical length of 30 μm or more in a region where the illuminance difference from the surrounding normal region is 10 gray or more,
The concavo-convex defect is a black-and-white defect in which the horizontal and vertical lengths are each 30 μm or more in the region where the illuminance difference from the surrounding normal region is 10 gray or more,
The scratch defect is the defect having a width of 30 μm or more and a length of three times or more of the width in the region where the illuminance difference from the surrounding normal region is 10 gray or more. The optical film inspection apparatus described. In the method of irradiating light from a light source on one side of the film to be transported and imaging the film with an imaging device to detect defects in the optical film,
A method for inspecting an optical film, wherein a light irradiation region of the film irradiated with the light and a part of an imaging region of the film to be imaged overlap.   The optical film inspection method according to claim 11, wherein the light source and the imaging device are arranged so as to be separated from each other in a transport direction of the film.   The optical film inspection method according to claim 11 or 12, wherein the light irradiation direction of the light source and the imaging direction of the imaging device are arranged in parallel.   The optical film inspection method according to claim 11, wherein the light irradiation direction of the light source and the imaging direction of the imaging device are arranged to be non-parallel.   Depending on the transfer direction of the film, the imaging region is divided into two or more sub-imaging regions having different illuminance ranges, and the film is imaged each time the film is transferred by the width of the sub-imaging region, The optical film inspection method according to claim 11, wherein an image of the entire film is acquired for each of the sub imaging regions.   The optical film inspection method according to claim 15, wherein the entire image of the film is acquired for each sub imaging region by combining the captured images received from the sub imaging regions for each sub imaging region.

Images