Sheet inspection device

Abstract

To discriminate between a fisheye and foreign matter, thanks to high robustness against the shape of the fisheye and the thickness, etc., of a sheet.SOLUTION: Provided is a sheet inspection device comprising: a first light source including a first LED light source and a diffusion member for diffusing light emitted from the first LED light source; a second light source for emitting light directly from a second LED light source; and imaging means for capturing an image of a sheet-like inspection object by light entering from an inspection object region of the inspection object when irradiated from the first and the second light sources, the sheet inspection device inspecting the inspection object on the basis of the image captured by the imaging means. A plurality of first light sources are arranged sandwiching the inspection object region therebetween, and the second light source is located at a position where the light having been emitted from the second light source and passed through the inspection object region enters directly to the imaging means.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a sheet inspection device.

Background Art

[0002] In a production line for manufacturing or processing a sheet, an inspection device for detecting defects such as fish eyes and foreign matters in the sheet has been proposed.

[0003] As such an inspection device, for example, as described in Patent Document 1, an inspection device capable of identifying and detecting fish eyes and foreign matters has been proposed. However, it has a complex configuration such as using a surface light source, and depending on the arrangement adjustment of the slit plate, it is difficult to identify and has poor robustness and low reproducibility.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention has been made in view of the above problems, and an object thereof is to provide a technique having high robustness against the shape of fish eyes, the thickness of a sheet, etc., and capable of discriminating fish eyes and foreign matters.

Means for Solving the Problems

[0006] The present invention for solving the above problems is a first light source including a first LED light source and a diffusion member that diffuses the light emitted from the first LED light source, a second light source that emits light from a second LED light source, imaging means for imaging an image of the object to be inspected by light incident from an inspection target region of the sheet-like object to be inspected when irradiated by the first light source and the second light source; A sheet inspection apparatus comprising: and inspecting the object to be inspected based on the image captured by the imaging means, a plurality of the first light sources are arranged with the inspection target region therebetween, The second light source is arranged at a position where light emitted from the second light source and transmitted through the inspection target region is directly incident on the imaging means.

[0007] According to this, light incident from the first LED light source and diffused by the diffusion member causes light emitted from various first LED light sources to enter the inspection target region from various angles, and light emitted from the second LED light source directly enters the inspection target region. By performing inspection based on an image captured by light incident on the imaging means from the inspection target region irradiated by these lights, the robustness against the shape of the fish-eye and the thickness of the sheet-like object to be inspected is high, and the fish-eye and foreign matters can be stably discriminated. According to the present invention, such a sheet inspection apparatus can be provided at low cost with a simple configuration of a first LED light source, a diffusion member, and a second LED light source. Further, since the sheet inspection apparatus is configured by combining the first LED light source and the diffusion member and the second LED light source, the degree of freedom in arranging the first LED light source and the diffusion member and the second LED light source is high.

[0008] Further, in the present invention, the diffusion member may have a reflecting surface that diffusely reflects the light emitted from the first LED light source.

[0009] According to this, the diffusion state of the light emitted from the first LED light source can be adjusted by the shape of the reflecting surface.

[0010] Further, in the present invention, The diffusion member may have a light guide diffusion part that guides and diffuses the light emitted from the first LED light source.

[0011] According to this, the diffusion state of the light emitted from the first LED light source can be adjusted by the material, shape, surface state, etc. of the light guide diffusion member.

[0012] Also, in the present invention, The first LED light source and the second LED light source may be white LED light sources that emit white light.

[0013] According to this, a thick defect like a fish eye can be clearly identified as an obvious defect, and defects such as carbides can be identified by color.

[0014] Also, in the present invention, The first LED light source may be a white LED light source that emits white light, and the second LED light source may be a blue LED light source that emits blue light.

[0015] According to this, a thick defect like a fish eye can be clearly identified as an obvious defect, and the contrast of dark defects such as carbides can be enhanced.

Effects of the Invention

[0016] According to the present invention, the robustness against the shape of a fish eye, the thickness of the sheet, etc. is high, and a fish eye and a foreign object can be discriminated.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0018] 〔Application Example〕 Hereinafter, application examples of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing the configuration of the main part including the lighting device 20 of the sheet inspection apparatus 100 to which the present invention is applied. The sheet inspection apparatus 100 is an apparatus that images a sheet S with a camera 10 and inspects the presence or absence of defects based on the captured image.

[0019] As shown in FIG. 1, in the sheet inspection apparatus 100, a camera 10 and lighting systems 21, 22, and 23 are arranged with the sheet S to be inspected sandwiched therebetween. The lighting systems 21 and 22 are arranged so as to face each other across the inspection target region Ri of the sheet S in a direction parallel to the sheet S. The lighting system 23 is arranged at a position sandwiched between the lighting systems 21 and 22 in a direction parallel to the sheet S.

[0020] The lighting system 21 includes an LED light source 211 and a diffusion member 212. It is desirable for the lighting system 21 to approach the sheet S. The LED light source 211 is arranged to emit light downward (opposite to the sheet S) in FIG. 1. The diffusion member 212 includes a diffusion plate 212a having a semi-circular curved surface shape and a diffusion plate 212b. The upper surface (the side of the LED light source 211) of the diffusion plate 212b forms an uneven surface. The light emitted from the LED light source 211 is diffusely reflected in random directions by the diffusion plate 212a and the diffusion plate 212b of the diffusion member 212 arranged to face the light emitting portion of the LED light source 211. The lighting system 22 including the LED light source 221 and the diffusion member 222 also has the same configuration and function as the lighting system 21.

[0021] The LED light source 231 that constitutes the illumination system 23 emits light toward the upper side (sheet S side) of FIG. 1, and is arranged at a position where the emitted light passes through the inspection target region Ri of the sheet S and directly enters the camera 10 directly.

[0022] The camera 10 is a color camera or a monochrome camera. When a color camera is used as the camera 10, as the LED light sources 211, 221, and 231, light sources including LEDs that emit white light can all be used. Also, when a monochrome camera is used as the camera 10, as the LED light sources 211 and 221, light sources including LEDs that emit white light, and as the LED light source 231, a light source including an LED that emits blue light can be used.

[0023] FIG. 3 schematically shows an example of an image obtained by imaging the sheet S with the camera 10 using the illumination systems 21 to 23. FIG. 3(A) shows an image of the sheet S in which "burning" has occurred. FIG. 3(B) shows an image of the sheet S in which "fish-eye" has occurred. FIG. 3(C) shows an image of the sheet S in which "stain" has occurred.

[0024] According to the configuration shown in FIG. 1, the diffusion plates 212a and 212b of the illumination system 21 can generate light reflected at various angles. The same effect can also be obtained for the diffusion plates 222a and 222b of the illumination system 22. In this way, the light incident on the inspection target region Ri at various angles can be made to enter the fish-eye FE that can be formed in a random shape, and the refracted light by the fish-eye FE can be made to enter in the optical axis direction of the camera 10. Thereby, as shown in FIG. 3(B), the "fish-eye" can be recognized as a clear defect with its entire image.

[0025] Furthermore, with only the indirect light from the illumination systems 21 and 22, in a line that produces sheets S of different thicknesses, when detecting defects, the dynamic range of the dark defect region is insufficient. Therefore, by providing the LED light source 231, the dynamic range of the dark defect region can be ensured.

[0026] Thus, according to the sheet inspection apparatus 100, regarding the defects of the sheet S, it is possible to identify on the image a so-called foreign matter such as "stain", a "fish-eye including a foreign matter", and "a fish-eye only". If it is possible to stably determine whether it is a foreign matter (including a "fish-eye including a foreign matter") or "a fish-eye only", the image of the "fish-eye including a foreign matter" is classified as a harmful defect, and the image of the "fish-eye only" is classified as a harmless defect. By increasing the inspection object that can be treated as a harmless defect, it is also possible to improve the yield. In addition, when a person inspects It is also possible to stably determine the type of defect by visually observing the inspection image, and an inspection image with high visibility can be obtained.

[0027] Such a sheet inspection apparatus 100 can be inexpensively realized with a simple configuration including the LED light source 211 and the diffusion member 212, the LED light source 221 and the diffusion member 222, and the LED light source 231. In addition, by using the lighting device 20 including the LED light source 211 and the diffusion member 212, the LED light source 221 and the diffusion member 222, and the LED light source 231, the degree of freedom in arranging each lighting system is high. In addition, various adjustments can be made according to the shapes and processing of the diffusion member 212 and the diffusion member 222.

[0028] [Example 1] Hereinafter, with reference to each drawing (including the drawings once described in the above application example) in sequence, the embodiments for carrying out the present invention will be exemplarily and specifically described based on the examples. However, the specific configurations described in this example are not intended to limit the scope of the present invention only to those, unless otherwise specified.

[0029] (Main component configuration) The sheet inspection apparatus 100 according to Example 1 is an apparatus that images a sheet-like inspection object such as a film made of PE (polyethylene), PS (polystyrene), PET (polyethylene terephthalate), PP (polypropylene), or nylon, and inspects the presence or absence of defects based on the captured image. The sheet inspection apparatus 100 corresponds to the sheet inspection apparatus of the present invention.

[0030] FIG. 1 is a diagram showing a schematic configuration of a main part of a sheet inspection apparatus 100 including an illumination device 20. FIG. 2 is a block diagram showing an overall configuration of the sheet inspection apparatus 100.

[0031] A camera 10 and illumination systems 21, 22, and 23 are arranged with a sheet S to be inspected therebetween. The illumination systems 21 and 22 are arranged to face each other across an inspection target region Ri of the sheet S in a direction parallel to the sheet S. The illumination system 23 is arranged at a position sandwiched between the illumination systems 21 and 22 in a direction parallel to the sheet S. The sheet S is conveyed in a direction parallel to the paper surface by a conveying means (not shown). Here, the illumination device 20 is constituted by the illumination systems 21, 22, and 23. Here, the camera 10 corresponds to the imaging means of the present invention. The sheet S corresponds to the object to be inspected of the present invention. The illumination systems 21 and 22 correspond to a plurality of first light sources of the present invention. Also, the illumination system 23 corresponds to the second light source of the present invention.

[0032] The illumination system 21 includes an LED light source 211 and a diffusion member 212. The LED light source 211 is a light source including, for example, an LED that emits white light. The LED light source 211 is arranged in the illumination system 21 to emit light downward in FIG. 1 (opposite side to the sheet S). The diffusion member 212 includes a semi-circular curved diffusion plate 212a and a plate-shaped diffusion plate 212b. The upper surface (LED light source 211 side) of the diffusion plate 212b forms an uneven surface. The light emitted from the LED light source 211 is diffusely reflected in random directions by the diffusion plate 212a and the diffusion plate 212b of the diffusion member 212 arranged to face the light emitting part of the LED light source 211, and irradiates the inspection target region Ri of the sheet S as indirect incident light Di. In the illumination system 21, a plurality of the LED light sources 211 may be arranged linearly or individually in a direction orthogonal to the paper surface of FIG. 1 (width direction of the sheet S). Here, the LED light source 211 corresponds to the first LED light source and the white LED light source of the present invention. The diffusion member 212 corresponds to the diffusion member of the present invention. Also, the diffusion plate 212a and the diffusion plate 212b correspond to the reflecting surfaces of the present invention.

[0033] The illumination system 22 has the same configuration as the illumination system 21 and includes an LED light source 221 and a diffusion member 222. The LED light source 221 is a light source including, for example, an LED that emits white light. The LE D light source 221 is arranged in the illumination system 22 to emit light downward (opposite to the sheet S) in FIG. 1. The diffusion member 222 includes a diffusion plate 222a having a semi-circular curved surface and a diffusion plate 222b. The upper surface (the side of the LED light source 221) of the plate-shaped diffusion plate 222b forms an uneven surface. The light emitted from the LED light source 221 is diffusely reflected in random directions by the diffusion plate 222a and the diffusion plate 222b of the diffusion member 222 arranged opposite to the light-emitting portion of the LED light source 221, and enters the inspection target region Ri of the sheet S as the indirect incident light Di. In the illumination system 22, a plurality of the LED light sources 221 may be arranged linearly or may be arranged individually in the direction orthogonal to the plane of FIG. 1 (the width direction of the sheet S). Here, the LED light source 221 corresponds to the first LED light source and the white LED light source of the present invention. The diffusion member 222 corresponds to the diffusion member of the present invention. Further, the diffusion plate 222a and the diffusion plate 222b correspond to the reflecting surface of the present invention.

[0034] The illumination system 23 includes an LED light source 231. The LED light source 231 is a light source including, for example, an LED that emits white light or blue light. In the illumination system 23, a plurality of the LED light sources 231 may be arranged linearly or may be arranged individually in the direction orthogonal to the plane of FIG. 1 (the width direction of the sheet S). The LED light source 231 emits light upward (toward the sheet S side) in FIG. 1, and is arranged at a position where it enters the inspection target region Ri as the direct incident light IDi, and the incident light passes through the inspection target region Ri of the sheet S and directly enters the camera 10. The LED light source 231 corresponds to the second LED light source, the white LED light source, and the blue LED light source of the present invention.

[0035] The camera 10 includes an optical system such as a lens and a CCD (Charge Coupled Device) image sen sor or a light receiving element such as a CMOS (Complementary Metal Oxide Semiconductor) image sensor. It includes elements. As the camera 10, a color camera or a monochrome camera can be used. A camera 10 in which the image sensor is arranged linearly in the width direction of the sheet S can be used, but the configuration of the camera 10 is not limited to this.

[0036] (Overall Configuration) The sheet inspection device 100 includes the above-mentioned camera 10, illumination systems 21, 22, 23, control unit 30, image processing unit 31, imaging control unit 32, illumination control unit 33, operation unit 34, display unit 35, inspection data database (DB) 40, and learning system 50.

[0037] The control unit 30 can be constituted by, for example, a computer including a CPU (Central Processing Unit) and storage devices such as a ROM (Read Only Memory) and a RAM (Random Access Memory). By expanding the program stored in the ROM or the like to the working area such as the RAM and executing it in the CPU, each function that meets a predetermined purpose can be realized. In the storage device, data such as programs for controlling and inspecting each part and parameters used for inspection are registered. The image processing unit 31 receives the image signal input from the camera 10 and performs image processing such as digital conversion and filtering. The imaging control unit 32 controls the imaging timing of the camera 10 and sets imaging conditions and the like. The illumination control unit 33 controls the light emission timing of the illumination systems 21, 22, 23 and sets illumination conditions such as the light amount.

[0038] The operation unit 34 inputs various operation instructions to the inspection device 1 and can be constituted by, for example, operation buttons, a mouse, a keyboard, etc. The display unit 35 displays information such as inspection images and inspection results and can be constituted by, for example, a liquid crystal panel or the like.

[0039] The inspection data DB 40 stores inspection data such as images for inspection by the inspection device 1 and inspection results. It is a storage device. The learning system 50 is a system that uses images of inspection results in which the type of defect has been identified from among images of inspection results stored in the inspection data DB 40 as teacher data to generate or re-learn an image recognition model to be used in the inspection program, and can adopt an appropriate learning method.

[0040] FIG. 3 shows a schematic example of an image of sheet S captured by camera 10 using illumination systems 21-23 shown in FIG. 1. FIG. 3(A) shows an image of sheet S with "burns". "Burns" are caused by factors such as carbonization of the film due to heating during film production. FIG. 3(B) shows an image of sheet S with "fisheyes". "Fisheyes" are caused by factors such as unmelted material forming a nucleus during film production that forms a convex shape. FIG. 3(C) shows an image of sheet S with "stains". "Stains" are caused by factors such as dust and dirt being mixed in during film production, or dirt and oil adhering during transport.

[0041] In the inspection image of a burn shown in Figure 3(A), when captured with a color camera, the color of the burn is visible in the center, and when captured with a monochrome camera, the core appears to be the same color as or darker than the surrounding texture. In the inspection image of a fisheye shown in Figure 3(B), the core is visible but appears lighter than the surrounding texture. The inspection image of a stain shown in Figure 3(C) is an example of a normal stain with no unevenness, and appears darker than the surrounding texture (dark defect).

[0042] According to the configuration shown in FIG. 1, it is possible to generate light reflected at various angles by the diffusion plates 212a and 212b from the light emitted from the LED light source 211 having high directivity. The same effect can also be obtained for the LED light source 221 and the diffusion plates 222a and 222b. In this way, the light incident on the inspection target region Ri at various angles can be made to enter the fish-eye FE that can be formed in a random shape, and the refracted light by the fish-eye FE can be made to enter in the optical axis direction of the camera 10. As a result, as shown in FIG. 3(B), the "fish-eye" can recognize its entire image as a bright defect.

[0043] Furthermore, in the configuration shown in FIG. 1, an LED light source 231 that emits light that directly enters the camera 10 through the sheet S is provided. With only the indirect light from the illumination systems 21 and 22, due to the thickness of the sheet S, the brightness corresponding to the sheet S changes in the image captured by the camera 10. In a line that produces sheets S of different thicknesses, when detecting defects, the dynamic range of the dark defect region is insufficient. By providing the LED light source 231, it is possible to secure the dynamic range of the dark defect region. According to the thickness of the sheet S, the illumination control unit 33 may control the LED light source 231.

[0044] When a monochrome camera is used as the camera 10, when the carbonization level of the foreign matter contained in the "fish-eye containing foreign matter" is low, it becomes a brown low contrast, and when the carbonization level is high, it becomes black. Therefore, in order to detect the brown low contrast, it is effective to use a blue LED light source that is a complementary color as the LED light source 231. Also, when a color camera is used as the camera 10, since the above-described characteristics can be captured depending on the color even with white light, a white LED light source can be used as the LED light source 231.

[0045] Regarding "fish eyes", fish eyes with undissolved fibers or the like as nuclei (also referred to as "only fish eyes") and fish eyes with carbonized foreign substances or the like as nuclei (also referred to as "fish eyes containing foreign substances") can occur. The "burn" shown in Fig. 3(C) above corresponds to "fish eyes containing foreign substances". In addition, among the defects, there are harmful defects such as foreign substances and those that can be treated as harmless defects depending on the degree, such as fish eyes. According to the sheet inspection device 100, regarding the defects of the sheet S to be inspected, so-called foreign substances such as "stains" and "fish eyes containing foreign substances" and "only fish eyes" can be identified on the image. If it is possible to stably determine whether it is a foreign substance (including "fish eyes containing foreign substances") or "only fish eyes", the image of "fish eyes containing foreign substances" can be classified as a harmful defect, and the image of "only fish eyes" can be classified as a harmless defect, and by increasing the inspected objects that can be treated as harmless defects, it is also possible to improve the yield. In addition, according to the sheet inspection device 100, it is also possible to stably determine whether it is a foreign substance (including "fish eyes containing foreign substances") or "only fish eyes" by a person visually inspecting the inspection image, and an inspection image with high visibility can be obtained.

[0046] Such a sheet inspection device 100 can be inexpensively realized with a simple configuration including an LED light source 211 and a diffusion member 212, an LED light source 221 and a diffusion member 222, and an LED light source 231. In addition, by using the lighting device 20 composed of the LED light source 211 and the diffusion member 212, the LED light source 221 and the diffusion member 222, and the LED light source 231, the degree of freedom in the arrangement of each lighting system is high. In addition, various adjustments are possible depending on the shape and processing of the diffusion member 212 and the diffusion member 222.

[0047] In addition, by constructing a system that combines the optical model according to this embodiment, which has high robustness against visual recognition by humans, and the image recognition model by AI, the yield can be improved, and labor can be saved by automatic recognition by AI. Furthermore, optimization of the preservation plan is also possible by digitizing and databaseizing the inspection data.

[0048] [Modification Example] In the above-described First Embodiment, the illumination systems 21 and 22 and the illumination system 23 are caused to emit light simultaneously to capture an image of the inspection target region Ri. However, the imaging control unit 32 and the illumination control unit 33 cause the illumination systems 21 and 22 to emit light to capture a first image of the inspection target region Ri, and cause the illumination system 23 to emit light at a different timing to capture a second image. In the image processing unit 31, a composite image can also be used for inspection by performing a composite process on the first image and the second image. Further, without performing the composite process, each of the first image and the second image can also be used for inspection.

[0049] [Second Embodiment] FIG. 4 shows a schematic configuration of a main part including the illumination device 60 of the sheet inspection apparatus 200 according to the second embodiment. FIG. 5 is a block diagram showing the overall configuration of the sheet inspection apparatus 200 according to the second embodiment. The illumination device 60 includes an illumination system 23, an illumination system 24, and an illumination system 25. The arrangement and configuration of the illumination system 23 are the same as those in the first embodiment. The illumination system 24 and the illumination system 25 are arranged so as to face each other with the inspection target region Ri of the sheet S interposed therebetween in a direction parallel to the sheet S. The same reference numerals are given to the configurations common to the first embodiment, and detailed descriptions thereof are omitted. Here, the sheet inspection apparatus 200 corresponds to the sheet inspection apparatus of the present invention.

[0050] The lighting system 24 includes an LED light source 241 and a light guide member 242. The LED light source 241 is a light source including, for example, an LED that emits white light. The LED light source 241 is arranged in the lighting system 24 to emit light upward (toward the sheet S side) in FIG. 4. The light guide member 242 is arranged above in the emission direction of the LED light source 241. A diffusion surface 242a having a partial circular curved surface is formed on the inspection target region Ri side of the upper part (sheet S side) of the light guide member 242. The diffusion surface 242a has a curved surface shape that is concave on the inspection target region Ri side, and is, for example, subjected to sandblasting. The diffusion surface 242a is not limited to sandblasting, and may be roughened or have an uneven surface formed by an appropriate method. The light emitted from the LED light source 241 is emitted from the diffusion surface 242a via the light guide member 242. At this time, since the diffusion surface 242a is sandblasted or the like, light diffused in random directions is emitted from the diffusion surface 242a. In the lighting system 24, the LED light source 241 may be arranged in a plurality of lines or individually in a direction (width direction of the sheet S) orthogonal to the plane of FIG. 4. Here, the LED light source 241 corresponds to the first LED light source and the white LED light source of the present invention. The light guide member 242 corresponds to the light guide diffusion part of the present invention. In the direction (width direction of the sheet S), a plurality of them may be arranged linearly or may be arranged individually. Here, the LED light source 241 corresponds to the first LED light source and the white LED light source of the present invention. The light guide member 242 corresponds to the light guide diffusion part of the present invention.

[0051] The lighting system 25 has the same configuration as the lighting system 24 and includes an LED light source 251 and a light guide member 252. The LED light source 251 is a light source including, for example, an LED that emits white light. The LED light source 251 is arranged in the lighting system 25 to emit light upward (on the sheet S side) in FIG. 4. The light guide member 252 is arranged above in the emission direction of the LED light source 251. A diffusion surface 252a forming a partial circular curved surface is formed on the inspection target region Ri side of the upper part (sheet S side) of the light guide member 252. The diffusion surface 252a has a curved surface shape that is concave on the inspection target region Ri side and is, for example, subjected to sandblasting. The diffusion surface 252a is not limited to sandblasting, and may be roughened or have an uneven surface formed by an appropriate method. The light emitted from the LED light source 251 is emitted from the diffusion surface 252a via the light guide member 252. At this time, since the diffusion surface 252a is sandblasted or the like, light diffused in random directions is emitted from the diffusion surface 252a. In the lighting system 25, a plurality of the LED light sources 251 may be arranged linearly or individually in a direction orthogonal to the plane of FIG. 4 (the width direction of the sheet S). Here, the LED light source 251 corresponds to the first LED light source and the white LED light source of the present invention. The light guide member 252 corresponds to the light guide diffusion part of the present invention.

[0052] Here too, it is desirable to use a blue LED light source as the LED light source 231. Since the lighting system 23 including the LED light source 231 is the same as the sheet inspection apparatus 100, the description thereof is omitted. Also, in the lighting system 23, a plurality of the LED light sources 231 may be arranged linearly or individually in a direction orthogonal to the plane of FIG. 4 (the width direction of the sheet S).

[0053] As shown in FIG. 5, the sheet inspection apparatus 200 has a configuration common to the sheet inspection apparatus 100 except for the lighting system 24 and the lighting system 25. Since the functions of each part of the sheet inspection apparatus 200 are the same as those of the sheet inspection apparatus 100, detailed description thereof is omitted.

[0054] According to the configuration shown in FIG. 4, light emitted from the LED light sources 241 and 251 using highly directional LEDs can generate light that diffuses from the diffusion surfaces 242a and 252a at various angles, respectively. In this way, light incident on the inspection target area Ri at various angles can be made incident on the fish-eye FE that can be formed in a random shape, and the refracted light by the fish-eye FE can be made incident in the optical axis direction of the camera 10.

[0055] As a result, in the sheet inspection apparatus 200, similar to the sheet inspection apparatus 100 according to the first embodiment, regarding the defects of the sheet-like object to be inspected, so-called foreign matters such as "stains", "fish-eyes including foreign matters", and "fish-eyes only" can be identified on the image. If it is possible to stably determine whether it is a foreign matter (including "fish-eyes including foreign matters") or "fish-eyes only", the image of "fish-eyes including foreign matters" can be classified as a harmful defect, and the image of "fish-eyes only" can be classified as a harmless defect. By increasing the number of objects to be inspected that can be treated as harmless defects, it is also possible to improve the yield. Further, according to the sheet inspection apparatus 200, an inspection image with high visibility can be obtained, in which it is possible to stably determine whether it is a foreign matter (including "fish-eyes including foreign matters") or "fish-eyes only" even by a person visually inspecting the inspection image.

[0056] Such a sheet inspection apparatus 200 can be inexpensively realized with a simple configuration including the LED light source 241 and the light guide member 242, the LED light source 251 and the light guide member 252, and the LED light source 231. Further, by using the lighting device 60 including the LED light source 241 and the light guide member 242, the LED light source 251 and the light guide member 2 52, and the LED light source 231, the degree of freedom in arranging each lighting system is high. Further, various adjustments can be made according to the material, shape, and processing of the light guide member 242 and the light guide member 252.

[0057] Also in the second embodiment, a configuration similar to the modification of the first embodiment can be applied.

[0058] In addition, in order to make it possible to compare the constituent elements of the present invention with the configuration of the embodiments below, the constituent elements of the present disclosure are described with reference numerals in the drawings. <Appendix 1> A first light source (21, 22, 24, 25) including a first LED light source (211, 221, 241, 251) and a diffusion member (212, 222, 242, 252) that diffuses the light emitted from the first LED light source (211, 221, 241, 251), A second light source (23) that emits light from a second LED light source (231), An imaging means (10) that captures an image of the inspection object (S) by the light incident from the inspection target region (Ri) of the sheet-shaped inspection object (S) when irradiated by the first light source (21, 22, 24, 25) and the second light source (23), A sheet inspection apparatus (100, 200) that includes the above and inspects the inspection object (S) based on the image captured by the imaging means (10), A plurality of the first light sources (21, 22, 24, 25) are arranged with the inspection target region (Ri) therebetween, The sheet inspection apparatus (100, 200), characterized in that the second light source (23) is arranged at a position where the light emitted from the second light source (23) and transmitted through the inspection target region (Ri) directly enters the imaging means (10). <Appendix 2> The sheet inspection apparatus (100) according to Appendix 1, characterized in that the diffusion members (212, 222) have reflecting surfaces (212a, 222a) that diffusely reflect the light emitted from the first LED light sources (211, 221). <Appendix 3> The sheet inspection apparatus (200) according to Appendix 1, characterized in that the diffusion members (242, 252) have light guide diffusion parts (242, 252) that guide and diffuse the light emitted from the first LED light sources (241, 251). <Appendix 4> The sheet inspection apparatus (100, 200) according to any one of Appendices 1 to 3, characterized in that the first LED light sources (211, 221, 241, 251) and the second LED light source (231) are white LED light sources that emit white light. <Appended Note 5> The first LED light sources (211, 221, 241, 251) are white LED light sources that emit white light, and the second LED light source (231) is a blue LED light source that emits blue light. The sheet inspection device (100, 200) according to any one of appended notes 1 to 3, characterized in that.

Explanation of Signs

[0059] 10: Camera 21, 22, 23, 24, 25: Lighting system 100, 200: Sheet inspection device 211, 221, 231, 241, 251: LED light source 212, 222: Diffusion member 242, 252: Light guide member S: Sheet Ri: Inspection target area

Claims

1. A first light source including a first LED light source and a diffusion member that diffuses the light emitted from the first LED light source, A second light source that emits light from a second LED light source, Imaging means for imaging an image of the object to be inspected by the light incident from the inspection target region of the sheet-like object to be inspected when irradiated by the first light source and the second light source, A sheet inspection apparatus comprising the imaging means and inspecting the object to be inspected based on the image captured by the imaging means, A plurality of the first light sources are arranged with the inspection target region therebetween, The sheet inspection apparatus, wherein the second light source is arranged at a position where the light emitted from the second light source and transmitted through the inspection target region is directly incident on the imaging means.

2. The sheet inspection apparatus according to claim 1, wherein the diffusion member has a reflection surface that diffusely reflects the light emitted from the first LED light source.

3. The sheet inspection apparatus according to claim 1, wherein the diffusion member has a light guide diffusion portion that guides and diffuses the light emitted from the first LED light source.

4. The sheet inspection apparatus according to any one of claims 1 to 3, wherein the first LED light source and the second LED light source are white LED light sources that emit white light.

5. The sheet inspection apparatus according to any one of claims 1 to 3, wherein the first LED light source is a white LED light source that emits white light, and the second LED light source is a blue LED light source that emits blue light.

Images