JP2011133288A - Illumination method and lighting system for image inspection of cylindrical article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide illumination applying light to the inner surface of a cylindrical article from a plurality of directions, obtaining stable brightness, even if a surface for imaging the cylindrical article is a glossy surface, such as a surface of metal, and obtaining a captured image for improving precision of an image inspection. <P>SOLUTION: In the illumination method for brightly irradiating the cylindrical article 3 with a light, when inspecting an image obtained by imaging the cylindrical article 3 that uses an imaging means, namely, a camera 6 for imaging, light is applied in the imaging direction from the outside of the cylindrical article 3 from a plurality of light sources 2 that are disposed between the imaging means 6 and the cylindrical article 3, in parallel with an imaging direction 10 for imaging the cylindrical article. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to illumination for irradiating light on an object such as a product, and more particularly to an illumination method and an illumination apparatus for image inspection of a cylindrical article that irradiates light inside the cylindrical article.

  In recent years, electronic devices such as AV devices and personal computers are rapidly becoming portable and cordless, and there is an increasing demand for batteries that are small, light, and have high energy density as power sources for driving these devices. With the widespread use of electronic devices, the load power of the devices gradually increases, and there is a demand for batteries that are excellent in heavy load discharge performance.

In lithium secondary batteries, which are widely used as driving power sources for portable electronic devices and communication devices, a negative electrode plate is made of a carbonaceous material capable of occluding and releasing lithium, and the positive electrode plate is made of a transition material such as LiCoO _2. A composite oxide of metal and lithium is used as an active material, and thereby a secondary battery having a high potential and a high discharge capacity is obtained. Furthermore, in order to realize a lithium secondary battery having a high discharge capacity, it is possible to further increase the capacity by increasing the packing density of the active material, which is a power generation element, and storing more non-aqueous electrolyte.

  In addition, the demand for alkaline dry batteries typified by primary batteries, which are required as a power source for electronic devices, is rapidly increasing. As with secondary batteries, the density of power generation elements is increased, and more alkaline electrolyte is stored. High capacity can be achieved.

  However, as electronic devices and communication devices have become more and more multifunctional in recent years, demand for battery safety is increasing as capacity is further increased, and as the product life cycle of electronic devices is prolonged, There is a demand for improved quality over time. Leakage is a serious problem in improving productivity and high quality.

  In a cylindrical battery such as a cylindrical battery or a rectangular tube, which is a secondary battery or a primary battery, for example, a battery case is formed by compressing an insulating gasket by caulking an opening end of a bottomed cylindrical battery case inward. The case, the insulating gasket, and the sealing member are hermetically sealed and sealed. However, if a small amount of electrolytic solution adheres to the sealing part, the contact surface of the two constituent members of the opening structure of the gasket and the battery case in the sealing structure gets wet with the electrolytic solution, and a liquid leakage path is formed. Liquid leakage may occur when the electrolyte enters the leakage path. If the encapsulated electrolyte solution leaks from the sealing portion, not only will the equipment used be damaged, but the safety will also be impaired. For this reason, the sealing agent for preventing a liquid leak is applied to the sealing part of the battery case, and it is necessary to inspect whether the sealing agent is applied without missing in the manufacturing process. Thus, in the product using the cylindrical metal can, the inner wall needs to be inspected.

  Conventionally, in these inspections, for example, there is a system in which a cylindrical article such as a product is irradiated with light to create a suitable illumination environment, and then the object is imaged with an imaging camera and an appearance inspection is performed. Are known. As shown in FIG. 8, a half mirror 111 installed at an inclination of 45 ° on the observation axis 113 of the imaging camera 106 and an LED 102 serving as a light source unit that emits light from the side thereof are emitted from the LED 102. The reflected light is reflected by the half mirror 111, travels in the same direction as the observation axis 113, and is applied to the sealing agent 104 applied to the opening of the battery case 112. Further, a method has been proposed in which light reflected by the sealant 104 applied to the opening of the battery case 112 passes through the half mirror 111 and is imaged by the imaging camera 106 (see, for example, Patent Document 1).

  In addition, as shown in FIG. 9, the opening of the battery case 112 is illuminated with a large number of LEDs 102 mounted inward on the observation axis 113 of the imaging camera 106 and a ring-shaped holding frame 114 that irradiates light obliquely. There has been proposed a method of irradiating the applied sealing agent 104 and imaging the sealing agent 104 with an imaging camera 106 (see, for example, Patent Document 2).

JP 2006-46946 A JP 2008-139708 A

  However, in the prior art shown in Patent Document 1 and Patent Document 2 described above, when the surface of the inner surface of the opening of the battery case captures a surface on which the metal is regularly reflected, the irradiated light is only from one direction. Therefore, the brightness of the captured image varies greatly due to the difference in the state of the surface to be imaged and the slight inclination of the opening of the battery case, a stable image cannot be obtained, and it is difficult to improve the accuracy of the image inspection. There was a problem.

  The present invention has been made in view of the above-described conventional problems, and can irradiate light from a plurality of directions on the inner surface of a cylindrical article such as a battery case, and the imaging surface of the cylindrical article is a surface of a metal or the like. Even with such a glossy surface, stable brightness can be obtained. Accordingly, it is an object to provide illumination capable of obtaining a captured image that can improve the accuracy of image inspection.

  In order to solve the above object, the present invention provides an illumination method for brightly illuminating a cylindrical article when the cylindrical article is imaged by the imaging means and inspecting the captured image, and is disposed between the imaging means and the cylindrical article. In addition, light is emitted from the outside of the cylindrical article toward the imaging direction from a plurality of light sources arranged in parallel with the imaging direction for imaging the cylindrical article.

  According to the present invention, the inner surface of the cylindrical article can be irradiated with light from a plurality of directions, and even when the surface to be imaged of the cylindrical article is slightly different from the glossy surface of metal or the like and the surface to be imaged, Stable brightness can be obtained, and a captured image that can improve the accuracy of image inspection can be obtained.

1 is a schematic configuration diagram of a lighting device according to an embodiment of the present invention. The schematic block diagram of the illuminating device using the light diffusing plate which concerns on one embodiment of this invention. 1 is a schematic configuration diagram of a cylindrical lithium ion battery according to an embodiment of the present invention. Schematic diagram of annular groove and sealant of battery case according to the present invention (A) The schematic diagram which shows the illumination optical path with respect to the cyclic | annular support part of the battery case which concerns on a prior art, and a reflective optical path, (b) The illumination with respect to the cyclic | annular support part of the battery case which concerns on one embodiment of this invention Schematic diagram showing optical path and reflected optical path (A) Schematic diagram showing regions regularly reflected by illumination according to the prior art, (b) Schematic diagram showing regions regularly reflected by the illumination according to the prior art, (c) By illumination according to an embodiment of the present invention Schematic diagram showing the regular reflection area (A) The schematic diagram which shows the relationship between the regular reflection area | region and sealing agent application | coating lacking area | region which concerns on a prior art, (b) The relationship between the regular reflection area | region and sealing agent application | coating lacking area | region which concerns on one embodiment of this invention is shown Pattern diagram Schematic configuration diagram of a lighting device according to the prior art Schematic configuration diagram of a lighting device according to the prior art

  According to a first aspect of the present invention, in an illumination method for brightly illuminating a cylindrical article when the cylindrical article is imaged by the imaging means and inspecting the captured image, the cylindrical article is disposed between the imaging means and the cylindrical article, and By irradiating light from the outside of the cylindrical article toward the imaging direction from a plurality of light sources arranged in parallel with the imaging direction for imaging the cylindrical article, light from a plurality of directions is applied to the inner surface of the cylindrical article. Even if the imaging surface of the cylindrical article is a glossy surface such as metal, stable brightness can be obtained, and a captured image capable of image inspection can be obtained.

  In the second invention of the present invention, by having a space in the area in the imaging direction so that the cylindrical article can be directly imaged by the imaging means, by irradiating light from the light source toward the cylindrical object from outside the space, It becomes possible to obtain a picked-up image that can be inspected without blurring or darkening the picked-up image due to fogging or dirt such as glass provided with a half mirror or reflector installed between the cylindrical article and the image pickup means. .

  In the third invention of the present invention, by irradiating light of a color brighter than the color of the cylindrical article to be imaged from the light source, a black or brown sealant and a metal surface on which the sealant is not applied It is suitable for image inspection with large lightness difference even if it is a surface where regular reflection light is hard to be reflected due to peeling of the coating or plating layer formed by oxidizing the metal surface. Imaging becomes possible.

  In the fourth invention of the present invention, by irradiating the cylindrical article with light that totally reflects visible light from the light source, even when the metal surface not coated with the sealant is discolored due to oxidation or the like, The brightness difference with the sealant that is black or brown can be imaged more greatly, and imaging suitable for image inspection is possible.

  In the fifth aspect of the present invention, by irradiating the cylindrical article with white light from the light source, the oil component used during the processing of the annular groove is attached to the metal surface on which the sealant is not applied. In this case, it is possible to suppress a decrease in lightness due to refraction and the like, and it is possible to take a larger image of the lightness difference from the sealant which is black or brown, and it is possible to take an image suitable for image inspection.

  In the sixth aspect of the present invention, by irradiating the cylindrical article with light in a wavelength range in which radiant energy is suppressed from the light source, even when a non-black sealant is used, the wavelength of the sealant is absorbed. By using an image pickup unit that selectively picks up light, a difference in brightness can be increased, and image pickup suitable for image inspection can be performed.

  According to a seventh aspect of the present invention, in an illumination device that illuminates a cylindrical article when an image of the cylindrical article is picked up and inspected by an imaging unit, a hollow holding frame larger than the outer diameter of the cylindrical article, A plurality of light sources arranged in a row parallel to an imaging direction for imaging the cylindrical article in the hollow portion of the frame, and a light source unit for irradiating light toward the imaging direction, and the holding frame as the imaging unit and the cylinder For image inspection, it is possible to irradiate light from a plurality of directions on the inner surface of the cylindrical article and to obtain a captured image with a stable brightness suitable for image inspection. A lighting device can be provided.

  In the eighth aspect of the present invention, since the light source unit is an LED, it is possible to reduce the size, and even a plurality of inspections of cylindrical tubular articles having a diameter of about 10 mm to 30 mm such as batteries. It is possible to provide an illuminating device in which a plurality of light sources can be arranged in a row and arranged in an annular shape.

  In the ninth aspect of the present invention, the light source unit irradiates light of a color brighter than the color of the cylindrical article, so that the specularly reflected light is caused by peeling of the coating or plating layer formed by oxidizing the metal surface. Even if the surface is difficult to reflect, an illumination device for image inspection can be provided that can perform illumination that can obtain a captured image with stable brightness suitable for image inspection.

  In the tenth aspect of the present invention, a hollow light diffusion plate having a diameter larger than the outer diameter of the cylindrical article is provided inside the holding frame, so that the light sources are not arranged in an annular shape. Even if the structure is arranged only on a part of the surface, it is possible to irradiate light from the entire circumferential direction, so that it can be configured with fewer light sources.

  Next, the illumination method for image inspection will be described in detail with reference to the drawings, using the cylindrical lithium secondary battery according to one embodiment of the present invention as a cylindrical article, but the present invention is not limited to this. It may be a beverage can or a spray can. As shown in FIG. 3, the upper and lower end surfaces of an electrode plate group 36 in which a positive electrode plate 31 and a negative electrode plate 32 housed in a battery case 3 are spirally wound through a separator 33 as a porous insulator are insulated. The body 38 is disposed, the aluminum positive electrode plate lead 34 is led out from the positive electrode plate 31 and welded to the sealing plate 39, and the nickel negative electrode plate lead 35 is led out from the negative electrode plate 32 and welded to the battery case 3. Has a configuration. Next, after injecting the electrolytic solution into the battery case 3, the sealing plate 39 is fixed by caulking the opening of the battery case 3 through the gasket 30, and the airtightness in the battery case 3 is maintained. A cylindrical lithium secondary battery 40 is configured.

  Further, after the electrode plate group 36 including the positive electrode plate 31, the separator 33, and the negative electrode plate 32, the electrolytic solution, and the like are accommodated in the bottomed cylindrical battery case 3, as shown in FIG. An annular groove portion 3 a is formed on the outer peripheral surface, and an annular support portion 3 b is provided in which the annular groove portion 3 a bulges in the battery case 3. The sealing plate 39 shown in FIG. 3 is placed on the annular support portion 3b from the opening of the battery case 3 through the gasket 30, and the peripheral edge of the opening of the battery case 3 is bent inward by caulking. The opening of the case 3 is sealed. Further, prior to the step of sealing in order to improve the leakage resistance of the electrolyte, a black seal composed of asphalt or the like is formed on the annular support portion 3b of the battery case 3 in which the sealing plate is fitted via a gasket. Application of the agent 4 is performed.

  The state of the sealing agent 4 applied to the annular support portion 3b is imaged by the imaging unit, and the image is inspected to determine whether the sealing agent 4 is missing or uneven. In this case, since it is difficult to judge a dark image, it is necessary to irradiate a battery case 3 of a cylindrical lithium secondary battery, which is a cylindrical article, with a large amount of light in order to capture an image brightly.

  However, depending on the method of irradiating light, for example, when the sealant 104 is reflected by the half mirror 111 shown in FIG. 8 and applied to the opening of the battery case 112 in the coaxial direction, or the ring shown in FIG. When the sealing agent 104 applied to the opening of the battery case 112 is irradiated with illumination in which a large number of LEDs 102 are mounted inward on the holding frame 114, the annular support 3b is a metal surface and is mainly subject to regular reflection. Therefore, since light is emitted from only one direction, the brightness of the uncoated portion is not stable, and a captured image suitable for coating inspection cannot be obtained.

This is because, as shown in FIG. 5A, the regular reflection light of the inclined surface 24 is reflected in the direction of the imaging camera in the optical path 122 of the light radiated to the annular support 3b, but in the optical path 121, the annular support 3d. When the light is reflected by the inclined surface 25 existing in FIG. 1, the regular reflection light is not reflected in the direction of the imaging camera. For this reason, on a glossy curved surface such as a metal surface of the annular support portion 3b, there is reflected light and non-reflected light, and only the reflected light is imaged by the imaging camera, which will be described in more detail later. Only a narrow range is picked up and picked up in a thin circular shape. The shape of the annular groove and the angle of the inclined surface present in the annular support part have slight variations, and the positioning accuracy of the cylindrical article also varies, so that the captured annular image varies in both radius and position. Become.

  In the illumination method according to an embodiment of the present invention, as shown in FIG. 1, a light source is provided between a battery case 3 of a cylindrical lithium secondary battery that is a cylindrical article and an imaging camera 6 that is an imaging means. Several LED2 is arrange | positioned and the sealing agent 4 apply | coated to the cyclic | annular support part 3b in the opening part of the battery case 3 is illuminated brightly. The plurality of LEDs 2 are arranged in a hollow protective frame 1 larger than the outer diameter of the battery case 3 in a row in parallel with the imaging direction 10 for imaging the battery case 3, and the imaging direction as in the optical paths 5 and 7. 10 is irradiated with light.

  From a plurality of light sources arranged in a row in parallel with the imaging direction 10, light is emitted toward the imaging direction 10 as in the optical paths 5 and 7. As shown in FIG. 5B, the optical path 7 of the light irradiated on the annular support portion 3b reflects the specularly reflected light of the glossy inclined surface 24 in the direction of the imaging camera 6, and further the light irradiated on the annular support portion 3b. The specularly reflected light of the glossy inclined surface 25 is also reflected in the direction of the imaging camera 6 to collect double light in the imaging camera 6, and the sealing agent 4 imaged by the imaging camera 6 is removed. Since the image of the annular support portion 3b that is included is captured in a thick annular shape, it is possible to perform imaging that can improve the determination accuracy in the image inspection. This can relieve slight variations in the shape of the annular groove and the angle of the inclined surface existing in the annular support, and can capture an annular image with reduced variation in positioning accuracy of the cylindrical article. It is possible to capture a highly accurate image with reduced variations.

  Further, as shown in FIG. 2, a hollow holding frame 1 larger than the outer diameter of the battery case 3 is provided between the imaging camera 6 as an imaging means and the battery case 3 of a cylindrical lithium secondary battery as a cylindrical article. In the hollow portion of the protective frame 1, LEDs 2 as a plurality of light sources are arranged in a row in parallel with the imaging direction 10 for imaging the battery case 3. Furthermore, a light diffusion plate 9 which is a light diffusion portion having a diameter larger than the outer diameter of the battery case 3 is provided in the hollow portion of the protective frame 1. The light emitted from the LED 2 is diffused by the light diffusing plate 9, and illuminates the sealing agent 4 applied to the battery case 3 by irradiating the light in the imaging direction 10. Although the light diffusing plate 9 is provided, the total number of the LEDs 2 can be reduced to improve the cost power and the power consumption can be reduced. However, it is possible to perform imaging that can improve the determination accuracy in the image inspection.

  FIGS. 6A to 6C are diagrams showing regions that can be imaged with specularly reflected light when the imaging camera 6 images the sealing agent 4 applied to the annular support portion 3b of the battery case 3. FIG. 6 (a) shows a seal applied to the annular support portion 3b and the annular support portion 3b of the battery case 3 using an illumination device that irradiates light in the same direction as the observation axis 113 shown in FIG. An area 41 where the light regularly reflected when the stop agent 4 is imaged can be imaged is shown. The region 41 is only a part of the annular support 3b in a narrow range, and the sealant 4 generated in the narrow region 41 can be inspected for chipping or cutting, but the entire surface of the annular support 3b is inspected. It is difficult.

  6B is applied to the annular support portion 3b and the annular support portion 3b of the battery case 3 using the observation shaft 113 and the illumination device that emits light from the oblique direction as shown in FIG. The area | region 42 which can image the specularly reflected light when imaging the sealing agent 4 which was done is shown. The region 42 is divided into regions that are regularly reflected as the annular support portion 3b is inclined. Although chipping or cutting of the sealant 4 generated within the two regions 41 can be inspected, it is difficult to inspect the entire surface.

FIG. 6C shows an annular support portion 3b of the battery case 3 and a sealant 4 applied to the annular support portion 3b when light is irradiated from a plurality of light sources arranged in parallel with the imaging direction of the present invention. It is a schematic diagram which shows the area | region which can image the light specularly reflected when imaged. As shown in FIG. 5 (b), the light irradiated from the light source is specularly reflected without being influenced by the inclined surface in the annular support portion 3b, and the region of the specularly reflected light having high illuminance in a wide range of the annular support portion 3b. 43. It is possible to inspect for chipping or cutting of the sealing agent 4 in the range of the wide region 43. As described above, the illumination method for image inspection according to the present invention can provide a wide area 43 in which the light emitted from the light source reaches the imaging camera regardless of the inclination of the annular support portion 3d.

  Embodiment 1 of the present invention will be described below with reference to detailed drawings. The cylindrical lithium secondary battery 40 shown in FIG. 3 which is a cylindrical article is not provided with a sealing plate 39 provided with a gasket 35 in the opening of the battery case 3 before caulking and sealing. As shown in FIG. 1, the imaging camera 6 was installed 300 mm apart above the opening of the battery case 3 in the state. Furthermore, the hollow holding frame 1 provided with the LEDs 2 arranged in a row between the imaging camera 6 and the battery case 3 was disposed. In addition, the LEDs 2 form a row of a plurality of LEDs 2 parallel to the imaging direction 10 for imaging the battery case 3 in the hollow portion of the holding frame 1, and the first LED 2 in the row is arranged 20 mm from the opening end of the battery case 3. Then, the last LED 2 in the row was arranged at a position of 100 mm with a distance of 4 times. The color emitted from the LED 2 was brighter than the battery case 3.

  The outer diameter of the battery case 3 is about 18 mm, and the annular support portion 3 b is formed at a position 5 mm below the opening end of the battery case 3. A holding frame 1 having a battery case 3 with an outer diameter of 30 mm which is larger than 18 mm was used. Next, the LED 2 irradiates light from the outside of the battery case 3 toward the imaging direction 10 and brightly illuminates the annular support 3b and the sealant 4 of the battery case 3, and images taken by the imaging camera 6 are examples. It was set to 1.

  As shown in FIG. 2, the imaging camera 6 was placed 300 mm apart above the opening of the battery case 3 in the state shown in FIG. Furthermore, the hollow holding frame 1 provided with the LEDs 2 arranged in a row between the imaging camera 6 and the battery case 3 was disposed. Furthermore, the LED 2 forms a plurality of LEDs 2 in a row parallel to the imaging direction 10 for imaging the battery case 3 in the hollow portion of the holding frame 1, and the first LED 2 in the row is arranged 20 mm from the opening end of the battery case 3. The last LED 2 in the row was placed at a position 100 mm apart by a distance of 4 times. The color irradiated from the LED 2 was whiter than the battery case 3, and a hollow light diffusion plate 9 was disposed inside the holding frame 1.

  Further, the outer diameter of the battery case 3 is about 18 mm, and the annular support portion 3 b is formed at a position 5 mm below the opening end of the battery case 3. Although it is desirable that the battery case 3 has a light diffusion plate 9 having a large outer diameter of 18 mm with respect to 18 mm and the LED rows are arranged in all the hollow portions in the holding frame 1, since the cost and power consumption can be greatly reduced, A light diffusing plate 9 was used. Next, an image obtained by irradiating light from the LED 2 and brightly illuminating the annular support portion 3b and the sealant 4 of the battery case 3 with the imaging camera 6 was taken as Example 2.

(Comparative Example 1)
As shown in FIG. 8, the imaging camera 106 was placed 300 mm apart above the opening of the battery case 112 equivalent to that of the first embodiment. Further, the half mirror 111 was installed on the observation axis 113 at an angle of 45 °, and the LED 102 for irradiating light from the side thereof was provided. Image captured by the imaging camera 106 when the light irradiated from the LED 102 is reflected by the half mirror 111 and travels in the same direction as the observation axis 113 and is irradiated with the sealant 104 applied to the opening of the battery case 112. Was designated as Comparative Example 1.

In order to compare Example 1 and Example 2 with Comparative Example 1, an optional chip was provided in the sealant 4 applied. The captured images are shown in FIGS. 7 (a) and 7 (b). FIG. 7A shows an image captured in Comparative Example 1, and the chip 45 of the sealant 4 applied to the annular support portion 3d is cut out within the range of the region 41 where light is reflected by the illumination of Comparative Example 1. The image is picked up and judged as defective as an inspection. However, since this is not a chip but a chip, no electrolyte leakage path occurs. In addition, when a chipping that does not cover the region 41 occurs, it is difficult to image in the comparative example 1, and the inspection accuracy is not satisfied, resulting in an inspection with many erroneous recognitions. Lead to productivity deterioration.

  FIG. 7B is a schematic diagram of an image obtained by imaging the state of the annular support portion 3b and the sealant 4 that are imaged using the illumination according to the first and second embodiments of the present invention. As shown in FIG. 7B, the region 43 where the light of the annular support portion 3b illuminated by the illumination of the first and second embodiments is reflected is wide, and the chip 45 of the sealant 4 is also imaged. It was. All of the chips 45 generated in the region 43 are imaged, and a high-quality lithium secondary battery can be supplied because a high-precision inspection can be performed in the inspection stage.

  By using the illumination method and the illumination device of the present invention, the inner surface of the cylindrical article can be irradiated with light from a plurality of directions, and the imaging surface of the cylindrical article is slightly on the glossy surface such as metal or the imaging surface. Even when the inclination is different, stable brightness can be obtained, and an image capable of improving the accuracy of image inspection can be obtained. The shape is not limited to a cylindrical shape, and may be a flat shape.

  According to the present invention, in order to illuminate a cylindrical article comprising a hollow holding frame and an LED in which a plurality of LEDs are arranged in an inward posture in a hollow portion, the inner side or the outer side of the cylindrical article is illuminated. Light from multiple directions can be emitted, and even when the surface to be imaged of a cylindrical article is a slightly glossy surface such as metal or the angle of inclination of the surface to be imaged is slightly different, the lightness is as stable as when using a diffused light source. It can be obtained and is also useful for image inspection of dirt and scratches generated inside a cylindrical article.

1 Holding frame 2 LED
DESCRIPTION OF SYMBOLS 3 Battery case 3a Annular groove part 3b Annular support part 4 Sealant 5 Optical path 6 Imaging camera 7 Optical path 9 Light diffusing plate 10 Imaging direction 24 Inclined surface 25 Inclined surface 30 Gasket 31 Positive electrode plate 32 Negative electrode plate 33 Separator 34 Positive electrode lead 35 Negative electrode Lead 36 Electrode plate group 38 Insulator 39 Sealing plate 41 Region 42 Region 43 Region 45 Chip

Claims (10)

  In a lighting method for brightly illuminating a cylindrical article when the cylindrical article is imaged by the imaging means and inspecting the captured image, the imaging is arranged between the imaging means and the cylindrical article and images the cylindrical article An illumination method for image inspection of a cylindrical article, wherein light is emitted from a plurality of light sources arranged parallel to the direction from the outside of the cylindrical article toward the imaging direction.   The light source is irradiated with light from the outside of the space toward the cylindrical object from the outside of the space so that the imaging unit can directly image the cylindrical article. The illumination method for image inspection of the cylindrical article as described.   The illumination method for image inspection of a cylindrical article according to claim 1, wherein light of a color brighter than the color of the cylindrical article to be imaged is emitted from a light source.   The illumination method for image inspection of a cylindrical article according to claim 1, wherein the cylindrical article is irradiated with light that totally reflects visible light from a light source.   The illumination method for image inspection of a cylindrical article according to claim 4, wherein the cylindrical article is irradiated with white light from a light source.   The illumination method for image inspection of a cylindrical article according to claim 1, wherein the cylindrical article is irradiated with light in a wavelength region in which radiant energy is suppressed from a light source.   In an illumination device that illuminates a cylindrical article when an image of the cylindrical article is picked up and inspected by an imaging unit, a hollow holding frame larger than an outer diameter of the cylindrical article, and the cylindrical shape in the hollow portion of the holding frame A plurality of light sources arranged in parallel with an imaging direction for imaging the article, and a light source unit for irradiating light toward the imaging direction, and the holding frame of the imaging unit and the cylindrical article An illumination device for image inspection of a cylindrical article, wherein the illumination device is arranged in between.   The illumination device for image inspection of a cylindrical article according to claim 7, wherein the light source unit is an LED.   The illumination device for image inspection of a cylindrical article according to claim 7, wherein the illumination apparatus is a light source unit that emits light of a color brighter than the color of the cylindrical article.   The illumination device for image inspection of a cylindrical article according to claim 7, wherein a hollow light diffusion portion having a diameter larger than the outer diameter of the cylindrical article is provided inside the holding frame.

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