Inspection method and inspection device of float glass

Abstract

To provide an inspection method and an inspection device of float glass, which can accurately detect a defect at an edge part of a glass ribbon in a process of manufacturing the float glass.SOLUTION: An inspection device detects a defect D at an edge part Gy formed by a side edge part of a belt-like glass ribbon GR which is continuously sent out from a float bath so as to be conveyed. The device applies light to the edge part Gy along a front surface as one main surface of the glass ribbon GR, photographs an application portion of the light to the edge part Gy from a front surface side, and detects the defect D at the edge part Gy on the basis of image data of the photographed edge part Gy.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method and an apparatus for inspecting float glass. [Background technology]

[0002] Patent Document 1 discloses a method for manufacturing float glass, in which molten glass is supplied from a melting furnace onto molten metal in a float bath and formed into a glass ribbon while flowing on the molten metal. In this manufacturing method, the glass ribbon is sent downstream by top rolls arranged opposite to each other on both side edges in the width direction of the glass ribbon, and the width of the glass ribbon is prevented from narrowing due to surface tension. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-66548 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above manufacturing method, the glass ribbon is cut off from the edge portions, which are made up of side edges that have developed minute irregularities due to contact with the top roll, to form a finished product, and this finished product portion is inspected for defects such as bubbles and foreign matter using an optical inspection device.

[0005] It was previously thought that defects such as bubbles and foreign matter in the ears that are cut off during the process of making a product would have almost no effect on the finished product, but it has been discovered that when there are many defects in these ears, they have some effect on the product parts other than the ears. For this reason, it is desirable to inspect these ears for defects.

[0006] However, because the ears have minute irregularities due to contact with the top roll, inspection equipment that inspects product parts with smooth surfaces without irregularities will often make false detections, making it difficult to accurately detect defects.

[0007] Therefore, an object of the present invention is to provide a float glass inspection method and inspection device that can detect defects in the edge portions of a glass ribbon with high accuracy in the process of manufacturing float glass. [Means for solving the problem]

[0008] The present invention comprises the following configurations. (1) An inspection method for detecting defects in edge portions of a belt-shaped glass ribbon that is continuously fed out and transported from a float bath, the method comprising: irradiating the ear portions with light along one main surface of the glass ribbon; taking an image of the area where the ear portion is irradiated with light from the one main surface side; detecting defects in the selvage portions based on the captured image data of the selvage portions; Float glass inspection method.

[0009] (2) An inspection device for detecting defects in the edge portions of a belt-shaped glass ribbon that is continuously fed out of a float bath and transported, comprising: an illumination device that irradiates the ear portions with light along one main surface of the glass ribbon; a camera that photographs the area where the ear is irradiated with light from the one main surface side; an inspection unit that detects defects in the selvages based on image data from the camera; Equipped with Float glass inspection equipment. [Effects of the Invention]

[0010] According to the present invention, defects in the edge portions of a glass ribbon can be detected with high accuracy in the process of manufacturing float glass. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram of a float glass inspection device according to this embodiment. [Figure 2] FIG. 2 is a schematic diagram for explaining an example of the arrangement of lighting in the inspection device of FIG. [Figure 3] FIG. 3 is a schematic diagram for explaining the range of arrangement of illumination in the inspection device of FIG. [Figure 4] FIG. 4 is a flowchart illustrating the float glass inspection method according to this embodiment. [Figure 5] FIG. 5 is a schematic diagram showing an image acquired by the inspection method according to this embodiment. [Figure 6] FIG. 6 is a schematic diagram showing an image acquired by an inspection method according to a reference example. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram of a float glass inspection device 10 according to this embodiment, showing one side portion of a glass ribbon GR when viewed in cross section in the width direction.

[0013] As shown in FIG. 1, a float glass inspection device 10 according to this embodiment is installed in a production line for producing glass sheets by the float process, and is a device for detecting defects in edge portions Gy of a glass ribbon GR.

[0014] A production line for producing glass sheets by the float process mainly includes a melting furnace, a float bath, and an annealing furnace. This production line produces, for example, glass sheets for window glass, glass sheets for automobile windows, glass sheets used in displays such as flat panel displays, and glass sheets used as substrates for other electronic devices. In this production line, molten glass obtained from a melting furnace is formed into a glass ribbon GR consisting of a smooth, ribbon-shaped float glass in a float bath. The glass ribbon GR is then fed into a downstream annealing furnace while being prevented from narrowing due to surface tension by top rolls (not shown) arranged opposite both side edges in the width direction, i.e., the left and right directions on the paper surface of FIG. 1 . In the float bath, the top rolls may also function to widen the width of the glass ribbon GR. The glass ribbon GR fed into the annealing furnace is then cut along the width direction, and both side edges are cut along vertical cutting lines Cl extending in the conveying direction, i.e., perpendicular to the paper surface of FIG. 1 . As a result, the edge portions Gy of the glass ribbon GR, which are made up of both side edge portions having minute irregularities caused by contact with the top roll, are removed from the product portion Gp, resulting in a glass sheet of a predetermined size. As an example, the width direction size of the glass ribbon GR is approximately 100 mm to 500 mm for the edge portions Gy and approximately 700 mm to 5000 mm for the product portion Gp. Note that a numerical range expressed using "to" means a range that includes the numerical values ​​written before and after "to" as the lower and upper limits.

[0015] The inspection device 10 is disposed downstream of the annealing furnace. The inspection device 10 may be installed on only one side edge of the glass ribbon GR, or on both sides. Installation on both sides is preferable. In the following description, the inspection device 10 installed on one side edge will be described.

[0016] The inspection device 10 includes illuminators 11A and 11B, a camera 13, and an inspection unit 15. In this example, the inspection device 10 includes two illuminators 11A and 11B.

[0017] The illuminators 11A and 11B are diffuse illuminators that emit diffused light. These illuminators 11A and 11B are arranged at opposite positions in the width direction of the conveying path of the glass ribbon GR, and are each arranged near one of the main surfaces of the glass ribbon GR. One illuminator 11A is arranged on the outer side of the edge Ed of the glass ribbon GR in the width direction, and the other illuminator 11B is arranged on the inner side of the vertical cutting line Cl of the glass ribbon GR in the width direction. In other words, these illuminators 11A and 11B are arranged on both sides in the width direction of the edge Gy of the glass ribbon GR.

[0018] One of the illuminators 11A irradiates the edge portions Gy of the glass ribbon GR with light along the surface of the glass ribbon GR, from the outside toward the inside in the width direction of the glass ribbon GR. The other illuminator 11B irradiates the edge portions Gy of the glass ribbon GR with light along the surface of the glass ribbon GR, from the center toward the outside in the width direction of the glass ribbon GR. These illuminators 11A and 11B have, as an example, a flat light-emitting surface. The installation positions of the illuminators 11A and 11B will be described in detail later.

[0019] The camera 13 is, for example, a CCD (Charge Coupled Device) camera or a CMOS (Complementary Metal Oxide Semiconductor) camera. The camera 13 is disposed above the edge Gy of the glass ribbon GR and photographs the irradiated portion of the edge Gy that is irradiated with light from the illuminators 11A and 11B. The camera 13 is preferably disposed in a position that allows it to photograph the edge Gy from a direction that intersects with the surface of the glass ribbon GR. The camera 13 photographs the edge Gy from a direction that is at an angle of 60 to 120 degrees, preferably 80 to 100 degrees, and more preferably 85 to 95 degrees relative to the surface of the glass ribbon GR.

[0020] The arrangement of the illuminators 11A, 11B and the camera 13 relative to the glass ribbon GR will be described with reference to Figures 2 and 3. In the example of Figure 2, the illuminators 11A, 11B are provided at positions where the distances d1, d1' in the width direction of the glass ribbon GR between each light-emitting surface and the end of the ear portion Gy are, for example, about 10 mm to 200 mm. That is, the distance d1' in the width direction of the glass ribbon GR between the light-emitting surface of the illuminator 11B and the vertical cutting line Cl of the glass ribbon GR is 10 mm to 200 mm. Here, if the width of the ear portion Gy, i.e., the size of the ear portion Gy in the width direction of the glass ribbon GR, is 100 mm to 500 mm, the illuminator 11A is provided at a position where the distance from the vertical cutting line Cl of the glass ribbon GR is 110 mm to 700 mm. That is, the distance d1 in the width direction of the glass ribbon GR between the light-emitting surface of the illuminator 11A and the edge Ed of the glass ribbon GR is about 10 mm to 200 mm. 2, the illuminators 11A and 11B are provided at positions where the vertical distances d2 and d2' between the lower ends of the illuminators and the surface of the glass ribbon GR are, for example, 50 mm. The vertical size (length) of the illuminators 11A and 11B is, for example, 90 mm. The illuminators 11A and 11B are arranged so that their light-emitting surfaces are approximately perpendicular to the surface of the glass ribbon GR.

[0021] In the example shown in FIG. 2, the direction of the optical axis 131 of the camera 13 coincides with the direction intersecting the surface of the glass ribbon GR, and the field of view width 132 of the camera 13 is, for example, 110 mm to 700 mm. The field of view width 132 of the camera 13 is the distance between the intersection points of a straight line extending in the width direction of the glass ribbon GR along the surface of the glass ribbon GR and a virtual line (see the two-dot chain line in FIG. 2) indicating the captureable range (field of view) of the camera 13. Note that the position of the vertical cutting line Cl does not fluctuate because it corresponds to the position of a cutter fixed on the downstream side, but the position of the edge Ed can fluctuate by approximately ±30 mm due to the flow of the glass ribbon GR. Therefore, even if the width of the edge Gy is set to 100 mm to 500 mm, it will fluctuate by approximately ±30 mm, but the camera 13 can fit the entire width of the edge Gy within the field of view of the camera 13. The installation height of the camera 13, i.e., the vertical distance between the lens of the camera 13 and the surface of the glass ribbon GR, is determined according to the field of view and resolution of the camera 13 so that the entire width of the ear portion Gy is included in the field of view.

[0022] FIG. 3 shows the relationship between the lighting and the cameras in the example arrangement of FIG. Camera 13 captures the illuminated area illuminated by light from illuminations 11A and 11B. However, if the line of sight of camera 13 is reflected at a specific point on the subject and there is no illumination 11A or 11B in front of it, that point will not be captured in the image captured by camera 13. FIG. 3 shows lines of sight R1, R2, and R3 of camera 13. Of the lines of sight R1, R2, and R3 reflected at a specific point on ear Gy shown in FIG. 3, line of sight R2 reflected from the surface of ear Gy is due to deformation of the surface of ear Gy, i.e., reflected from the surface of ear Gy shown by the solid line in FIG. 3. Since there is no illumination 11A or 11B in front of line of sight R2, it is not captured in the image captured by camera 13. Therefore, the surface shape of ear Gy, i.e., the surface irregularities, will not be captured in the image captured by camera 13. On the other hand, the line of sight R3 reflected on the surface of the defect D contained inside the ear Gy has the lights 11A and 11B ahead of it, so the shape of the defect D appears bright in the image acquired by the camera 13. By arranging the lights 11A and 11B within the range S shown in FIG. 3, as described above, the defect D contained inside the ear Gy can be captured while suppressing the surface deformation of the ear Gy from appearing in the image acquired by the camera 13. Note that the line of sight R1 indicates the line of sight when there is no deformation on the surface of the ear Gy, that is, when reflected on the surface of the ear Gy shown by the dashed dotted line in FIG. 3. The line of sight R1 reflected on the surface of the ear Gy has neither the lights 11A nor 11B ahead of it, so it is not captured in the image acquired by the camera 13. As described above, the inspection device 10 according to this embodiment can detect defects such as bubbles and foreign matter inside the edge portion Gy with high accuracy. The arrangement and number of the illuminators 11A, 11B and the cameras 13 are not limited to those described above. The illuminators may be arranged on only one side of the width direction of the glass ribbon GR, or multiple illuminators may be arranged along the conveying direction, depending on the light intensity, the range of the inspection target, and the like. Furthermore, when the width of the edge portion Gy is large, for example, multiple cameras are installed along the conveying path, and the captured images of each camera are processed. This allows a camera with a narrow field of view relative to the width of the edge portion Gy to capture an image of the entire width of the edge portion Gy. Furthermore, for example, installing multiple cameras along the conveying direction enables inspection of the edge portion Gy over a wide area or at a faster conveying speed.

[0023] The range S shown in FIG. 3 is set so that the distances d1 and d1' between the illuminators 11A and 11B and the ends of the edge portions Gy (i.e., the edge Ed and the vertical cut line Cl) are at least a certain distance, and the distances d2 and d2' in the vertical direction between the lower ends of the illuminators 11A and 11B and the surface of the glass ribbon GR are as short as possible. If the distances d1 and d1' are too short, the distance d1 between the edge Ed and the illuminator 11A becomes too short due to fluctuations in the width of the edge portions Gy, and surface deformation of the edge portions Gy is reflected in the image captured by the camera 13. For this reason, the distance d1 is set to, for example, 50 mm or more, preferably 70 mm or more, and more preferably 80 mm or more. The same applies to d1'. On the other hand, if the distance d1 is increased, the light intensity of the illuminators 11A and 11B can be increased to prevent the defect D from being obscured by illuminating it. However, due to installation location constraints, the distance d1 is preferably, for example, 200 mm or less. The same applies to d1'. Furthermore, the shorter the distances d2 and d2', which are the installation heights of the illuminators 11A and 11B, the less visible the deformed surface of the edge portion Gy becomes and the more visible the defects D inside the edge portion Gy become. Therefore, the distances d2 and d2' are set to, for example, 200 mm or less, preferably 150 mm or less. On the other hand, if the distance d2 is too short, there is a risk of contact with the glass. Therefore, the distances d2 and d2' are set to, for example, 30 mm or more, preferably 50 mm or more. The distances d1 and d1' may be different from each other, and the distances d2 and d2' may also be different from each other. In particular, since the position of the vertical slicing line Cl does not fluctuate as described above, the distance d1' between the light-emitting surface of the illuminator 11B and the vertical slicing line Cl of the glass ribbon GR does not fluctuate. However, since the position of the edge Ed fluctuates due to the flow of the glass ribbon GR, the distance d1 between the light-emitting surface of the illuminator 11A and the edge Ed may fluctuate. Even if the distance d1 and the distance d1' are different from each other in this way, as long as the distances d1 and d1' satisfy the above conditions and the distances d2 and d2' satisfy the above conditions, the inspection device 10 can detect defects inside the ear portion Gy with high accuracy.

[0024] The longer the length of the lights 11A and 11B, that is, the longer the vertical length of the light-emitting surface, the more easily disturbances appear in the image captured by the camera 13, so the length is set to, for example, 180 mm or less, preferably 100 mm or less.

[0025] The inspection unit 15 is connected to the camera 13. Image data of the edge portions Gy is transmitted from the camera 13 to this inspection unit 15. The inspection unit 15 performs image processing on the image data from the camera 13 to detect defects in the edge portions Gy. When detecting defects in the edge portions Gy on both side edges of the glass ribbon GR, one inspection unit 15 may be connected to the cameras 13 provided on both side edges of the glass ribbon GR, and may perform image processing on the image data transmitted from each camera 13 to detect defects in the edge portions Gy.

[0026] The inspection device 10 also includes a background portion 17. The background portion 17 is made of a dark-colored sheet, for example, black, and is disposed on the back surface side, which is the other main surface, of the glass ribbon GR. The background portion 17 has an area larger than the imaging range of the camera 13. This enables the camera 13 to image the ear portion Gy within the range in which the background portion 17 is disposed.

[0027] Next, an inspection method using the inspection device 10 having the above configuration will be described with reference to the flowchart shown in FIG.

[0028] First, the illuminators 11A and 11B irradiate diffused light in a direction along the surface of the edge portions Gy of the glass ribbon GR, and the camera 13 captures an image of the edge portions Gy (step S1). As a result, image data of the camera 13 is transmitted to the inspection unit 15.

[0029] The inspection unit 15 performs image processing on the image data transmitted from the camera 13. Specifically, the inspection unit 15 first performs grayscale conversion on the image of the image data (step S2), and then performs binarization processing on the grayscale converted image data (step S3).

[0030] Then, based on the image of the binarized image data, the inspection unit 15 detects the position of the edge Ed, which is the side edge of the glass ribbon GR, whose position constantly fluctuates due to meandering and width variations, and identifies the range of the ear portion Gy between this edge Ed and the vertical cutting line Cl (step S4).

[0031] Next, the inspection unit 15 performs background subtraction processing on the acquired image of the ear portion Gy (step S5). Specifically, the inspection unit 15 compares the acquired image of the ear portion Gy with a previously acquired image of an ear portion Gy without defects.

[0032] Then, the inspection unit 15 detects defects in the edge portions Gy between the edges Ed of the glass ribbon GR and the vertical cut lines Cl in the acquired images of the edge portions Gy (step S6).

[0033] Furthermore, the inspection unit 15 clarifies the contour of the defect by neighbor joining processing, and identifies the shape and size of the defect (step S7).

[0034] Then, the inspection unit 15 acquires defect data such as the positions, distribution, sizes, and number of defects in the edge portions Gy of the glass ribbon GR (step S8).

[0035] The acquired defect data is accumulated (step S9) and, if necessary, fed back to the manufacturing conditions in the glass sheet manufacturing line (step S10). Specifically, the defect data acquired and accumulated by the inspection unit 15 is fed back to a control device that controls the entire manufacturing line, and is used to adjust manufacturing conditions such as the rotation speed of a stirrer that stirs the molten glass, for example.

[0036] By acquiring and accumulating defect data in this way, it is possible to grasp the situation, such as the number of defects occurring in the entire glass ribbon GR, including the edge portions Gy, that have occurred on the production line. Specifically, it is possible to grasp in real time the performance of the melting furnace, in which bubbles are likely to occur, and the fining tank, which removes bubbles (gas components) contained in the molten glass. It is also possible to analyze the behavior and occurrence mechanism of defects in the glass ribbon GR, including the edge portions Gy. Furthermore, by feeding back the defect data to the production line, it is possible to prevent bubbles, foreign matter, etc. from entering the product portion Gp of the glass ribbon GR in advance, thereby improving yield.

[0037] FIG. 5 is a schematic diagram showing an image P acquired by the inspection method according to this embodiment. In the inspection method according to the present embodiment, as shown in Fig. 5 , the image P acquired by the camera 13 and subjected to image processing shows only defects D such as bubbles and foreign matter in the edge portions Gy between the edges Ed of the glass ribbon GR and the vertical cut lines Cl. Therefore, according to the inspection method according to the present embodiment, only the defects D can be detected from the image P with high accuracy.

[0038] FIG. 6 is a schematic diagram showing an image P acquired by an inspection method according to a reference example. In this reference example, light is irradiated onto the edge Gy from directly above in the imaging direction, and the edge Gy is photographed. In the inspection method according to this reference example, the image P acquired by the camera 13 and subjected to image processing shows, as shown in FIG. 6, defects D, such as bubbles and foreign matter, along with traces R, in the edge Gy between the edge Ed of the glass ribbon GR and the vertical cut line Cl. The traces R are irregularities with a height of approximately 0 to 5 mm caused by the top roll. Therefore, in this reference example, the traces R are erroneously detected as defects. When photographing the edge Gy by irradiating light toward the imaging direction or irradiating light so that it passes through from the back surface opposite the imaging direction, as in this reference example, erroneous detection of the traces R caused by contact with the top roll is unavoidable, making it difficult to detect defects D, such as bubbles and foreign matter, with high accuracy. The present invention is effective for edge portions where traces R consisting of irregularities with a height of approximately 0.1 to 5 mm, particularly approximately 0.5 to 5 mm, are present.

[0039] As described above, the float glass inspection method and inspection device 10 according to this embodiment can suppress the false detection of traces R that have been adhered due to contact with the top roll, as in the reference example, and can detect only defects D such as bubbles or foreign matter in the edge portion Gy with high accuracy.

[0040] In particular, by irradiating diffused light along the surface of the glass ribbon GR, the emergence of traces R that have adhered due to contact with the top roll can be suppressed, making bubbles and foreign matter in the edge portion Gy more clearly visible, and defects D such as these bubbles and foreign matter can be detected with higher accuracy.

[0041] In addition, by irradiating light along the surface of the glass ribbon GR from both sides of the conveying direction to the edge portion Gy, the contours of bubbles, foreign matter, etc. in the edge portion Gy can be made clearer, and defects such as these bubbles and foreign matter can be detected with high accuracy.

[0042] Furthermore, by photographing the edge portion Gy from a direction perpendicular to the surface of the glass ribbon GR, false detections due to light reflection from the traces R that are formed by contact with the top roll can be further reduced, and only defects such as bubbles and foreign objects in the edge portion Gy can be detected with higher accuracy.

[0043] In addition, by arranging the dark background portion 17 on the side of the edge portion Gy opposite the camera 13, contrast is increased, thereby making it possible to more effectively detect defects such as bubbles and foreign matter in the edge portion Gy. Furthermore, by arranging the dark background portion 17 in this manner, it becomes easier for an operator to visually check for defects in the edge portion Gy while the glass ribbon GR is being transported above the background portion 17.

[0044] As such, the present invention is not limited to the above-described embodiments, and the invention also contemplates the mutual combination of the configurations of the embodiments, and modifications and applications by those skilled in the art based on the description in the specification and well-known technologies, and these modifications and applications are within the scope of the protection sought. For example, in the above-described embodiments, the lights 11A and 11B have planar light-emitting surfaces, but they may also be spotlights, and the type and shape of the lights are not limited.

[0045] As described above, the present specification discloses the following: (1) An inspection method for detecting defects in edge portions of a belt-shaped glass ribbon that is continuously fed out and transported from a float bath, the method comprising: irradiating the ear portions with light along one main surface of the glass ribbon; taking an image of the area where the ear portion is irradiated with light from the one main surface side; A float glass inspection method for detecting defects in the edge portions based on image data of the captured edge portions. This float glass inspection method reduces false detection of traces caused by contact with the top roll, compared to when photographing the edge by shining light in the direction of the image or by shining light through the back side opposite the image direction, and can detect only defects such as bubbles and foreign objects in the edge with high accuracy.

[0046] (2) The float glass inspection method according to (1), wherein the light irradiated onto the ear portion is diffused light. According to this float glass inspection method, diffused light is irradiated along the main surface of the glass ribbon, which prevents traces of adhesion due to contact with the top roll from appearing in the captured image data, making it possible to detect defects such as bubbles in the edge areas and foreign objects with higher accuracy.

[0047] (3) The float glass inspection method according to (1) or (2), in which light is irradiated along the main surface of the glass ribbon from both sides of the edge portions in a width direction perpendicular to the conveyance direction. According to this float glass inspection method, by irradiating the edge portions with light along the main surface of the glass ribbon from both sides in the conveying direction, the contours of bubbles, foreign matter, etc. in the edge portions can be made clearer, and defects such as these bubbles and foreign matter can be detected with higher accuracy.

[0048] (4) The float glass inspection method according to any one of (1) to (3), wherein the edge portions are photographed from a direction perpendicular to the main surface of the glass ribbon. This float glass inspection method can further reduce false detections caused by light reflection from marks left on the glass by contact with the top roll, and can more accurately detect only defects such as bubbles in the edge areas or foreign objects.

[0049] (5) The float glass inspection method according to any one of (1) to (4), wherein the image of the edge portion is taken in a state where a dark background portion is placed on the other main surface side of the edge portion that faces the one main surface. According to this float glass inspection method, contrast is increased, making it possible to more effectively detect defects such as bubbles in the edge areas and foreign matter.

[0050] (6) An inspection device for detecting defects in the edge portions of a belt-shaped glass ribbon that is continuously fed out of a float bath and transported, comprising: an illumination device that irradiates the ear portions with light along one main surface of the glass ribbon; a camera that photographs the area where the ear is irradiated with light from the one main surface side; an inspection unit that detects defects in the selvages based on image data from the camera; A float glass inspection device comprising: This float glass inspection device reduces false detection of traces caused by contact with the top roll, and can detect only defects such as bubbles and foreign objects in the edge areas with high accuracy, compared to when photographing the edge areas by shining light in the direction of the camera's photography or by shining light through the back side opposite the photography direction.

[0051] (7) The float glass inspection device according to (6), wherein the illumination is a diffuse illumination that irradiates the ear portion with diffused light. This float glass inspection device irradiates the glass ribbon with diffused light along its main surface, suppressing the emergence of traces of adhesion caused by contact with the top roll, thereby making bubbles and foreign matter in the edge areas more clearly visible, and enabling defects such as these bubbles and foreign matter to be detected with greater accuracy.

[0052] (8) The float glass inspection device according to (6) or (7), which includes a plurality of the illuminators and irradiates the ear portions with light along the main surface of the glass ribbon from both sides in the conveying direction. According to this float glass inspection device, by irradiating the edge portions with light along the main surface of the glass ribbon from lighting on both sides of the conveying direction, the contours of bubbles, foreign matter, etc. in the edge portions can be made clearer, and defects such as these bubbles and foreign matter can be detected with higher accuracy.

[0053] (9) The float glass inspection device according to any one of (6) to (8), wherein the camera photographs the edge portions from a direction perpendicular to the main surface of the glass ribbon. This float glass inspection device can reduce false detections caused by light reflection from marks left on the glass by contact with the top roll, and can detect only defects such as bubbles in the edge areas and foreign objects with higher accuracy.

[0054] (10) The float glass inspection device according to any one of (6) to (9), wherein a dark background portion is arranged on the side of the edge portion opposite to the camera. This float glass inspection device increases contrast, allowing for better detection of defects such as bubbles in the edge areas and foreign matter. [Explanation of symbols]

[0055] 10 Inspection equipment 11A,11B Lighting 13 Camera 15 Inspection Department 17 Background section D. Defect GR glass ribbon (float glass) Gy ears

Claims

1. 1. An inspection method for detecting defects in ear portions, which are side edge portions of a belt-shaped glass ribbon that is continuously fed out and transported from a float bath, comprising: irradiating the ear portions with light along one main surface of the glass ribbon; taking an image of the area where the ear portion is irradiated with light from the one main surface side; detecting defects in the selvage portions based on the captured image data of the selvage portions; Float glass inspection method.

2. Diffused light is irradiated onto the ear portion. The float glass inspection method according to claim 1 .

3. Light is irradiated onto the ear portions along the main surface of the glass ribbon from both sides in the width direction of the conveying path. The float glass inspection method according to claim 1 .

4. The edge portion is photographed from a direction intersecting with the main surface of the glass ribbon. The float glass inspection method according to claim 1 .

5. The ear portion is photographed in a state where a dark background portion is placed on the other main surface side of the ear portion opposite to the one main surface. The float glass inspection method according to any one of claims 1 to 4.

6. An inspection device for detecting defects in ear portions, which are side edge portions of a belt-shaped glass ribbon that is continuously fed out and transported from a float bath, comprising: an illumination device that irradiates the ear portions with light along one main surface of the glass ribbon; a camera that photographs the area where the ear is irradiated with light from the one main surface side; an inspection unit that detects defects in the selvages based on image data from the camera; Equipped with Float glass inspection equipment.

7. The lighting is diffuse lighting that irradiates diffused light onto the ear portion.

7. The float glass inspection device according to claim 6.

8. a plurality of the illuminators are provided, and light is irradiated onto the ear portions along the main surface of the glass ribbon from both sides in the conveyance direction; 7. The float glass inspection device according to claim 6.

9. The camera photographs the ear portion from a direction intersecting with the main surface of the glass ribbon.

7. The float glass inspection device according to claim 6.

10. A dark background portion is disposed on the ear portion on the opposite side to the camera. The float glass inspection device according to any one of claims 6 to 9.

Images