Glass plate manufacturing method

Abstract

To fetch and utilize detailed information of defects from glass plates determined as defective during an inspection step.SOLUTION: A glass plate manufacturing method includes a glass supplying step, a molding step, a cutting step, an inspection step and an information providing step. The inspection step includes: a determination step of acquiring an image of the glass plate by imaging the glass plate, and determining a quality of the glass plate based on the defectiveness contained in the image; and an information acquisition step for acquiring the defective information from the glass plate determined as defective in the determination step. The glass plate manufacturing method includes a first information providing step of providing the defective information acquired in the information acquisition step from the glass plate determined as defective in the determination step to a step before the inspection step.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for producing a glass sheet. [Background technology]

[0002] As is well known, displays such as liquid crystal displays and organic EL displays use glass plates.

[0003] In the process of manufacturing a glass sheet, molten glass produced in a melting furnace is supplied to a forming furnace (glass supplying process), and a long glass ribbon is continuously formed from the molten glass by a forming body disposed in the forming furnace (forming process). In the forming process, a downdraw method such as an overflow downdraw method, a slot downdraw method, or a redraw method is used (see, for example, Patent Document 1).

[0004] Thereafter, the glass ribbon is cut into predetermined lengths to cut out individual glass sheets from the glass ribbon (cutting process). Furthermore, both ends in the width direction of the cut out glass sheets are cut off, and then the glass sheets are inspected for defects such as protrusions (inspection process). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-89674 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the inspection process in the above-mentioned glass sheet manufacturing method, the glass sheets are judged as good or bad based on a predetermined standard related to defects. Glass sheets judged as good in the inspection process are transferred to the next process (e.g., a processing process, etc.). On the other hand, glass sheets judged as bad in the inspection process are discarded.

[0007] Defects in glass sheets are caused by a wide variety of factors, including defects caused by the glass supply process, the forming process, and the cutting process. However, in conventional glass sheet manufacturing methods, even if defects are detected in the inspection process, glass sheets determined to be defective are discarded without obtaining detailed information about the cause of the defect. If the cause of the defect can be identified before the glass sheet is discarded, the information can be used to improve the glass sheet manufacturing process.

[0008] Therefore, an object of the present invention is to obtain and utilize detailed information about defects from glass plates that have been determined to be defective in the inspection process. [Means for solving the problem]

[0009] The present invention has been made to solve the above-mentioned problems, and provides a method for manufacturing a glass plate, the method including a glass supplying step of supplying molten glass, a shaping step of forming a glass ribbon from the molten glass, a cutting step of cutting the glass ribbon to form sheet-shaped glass plates, and an inspection step of inspecting the glass plate, the inspection step including a determination step of acquiring an image of the glass plate by imaging the glass plate and judging whether the glass plate is good or bad based on defects contained in the image, and an information acquisition step of acquiring information of the defects from the glass plate judged to be defective in the determination step, and a first information provision step of providing the information of the defects acquired by the information acquisition step from the glass plate judged to be defective in the determination step to a step preceding the inspection step.

[0010] According to this configuration, defect information obtained by the information acquisition process from a glass plate determined to be defective in the judgment process is provided to a process preceding the inspection process by the first information provision process, making it possible to utilize this defect information to improve process management in these processes.

[0011] In this method, the information acquisition process includes a sample acquisition process for acquiring a sample from the glass plate judged to be defective in the judgment process, and an imaging process for acquiring a magnified image of the defect from the sample, and the information acquisition process may acquire the information of the defect based on the image of the glass plate acquired in the judgment process and the enlarged image acquired in the imaging process.

[0012] According to this configuration, it is possible to obtain detailed information about the defect based on the image of the glass plate obtained in the determining step and the enlarged image of the sample obtained in the imaging step.

[0013] The method may further include a processing step of processing the glass plate determined to be good in the determination step, and a second information providing step of providing the information on the defect acquired in the information acquiring step from the glass plate determined to be bad in the determination step to the processing step, whereby the information on the defect can be utilized to improve process management in the processing step.

[0014] In this method, the information acquisition process may acquire characteristic information from the glass plate judged to be good in the judgment process before or after processing the glass plate in the processing process, and the method may include a third information provision process for providing the characteristic information acquired by the information acquisition process from the glass plate judged to be good in the judgment process to a process preceding the inspection process.

[0015] According to this configuration, the characteristic information related to the glass sheet acquired in the third information acquisition step can be used to improve process management in the glass supplying step, the forming step, or the like. Effect of the Invention

[0016] According to the present invention, detailed information about defects in a glass plate determined to be defective in an inspection process can be obtained and utilized. [Brief description of the drawings]

[0017] [Figure 1] 1 is a flowchart showing a method for manufacturing a glass plate. [Diagram 2] 1 is a flowchart showing a glass supplying process. [Diagram 3] 13 is a flowchart showing a first inspection process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Figures 1 to 3 show an embodiment of the method for producing a glass plate according to the present invention.

[0019] 1, the method includes a glass supplying step S1, a forming step S2, a cooling step S3, a cutting step S4, a first inspection step S5, a packaging step S6, a transporting step S7, and a processing step S8. The method further includes a first information providing step S9, a second information providing step S10, and a third information providing step S11.

[0020] The glass supplying step S1 is a step of producing molten glass and supplying the molten glass to the forming step S2. As shown in Fig. 2, the glass supplying step S1 mainly includes a melting step S101, a fining step S102, a homogenization step S103, and a condition adjusting step S104.

[0021] In the melting step S101, the glass frits fed into the melting furnace are melted to produce molten glass. As the melting furnace, for example, there are those which produce molten glass by electrically heating the glass frits with electrodes provided inside, those which produce molten glass by heating the glass frits with a burner, and those which use both electrical heating and heating with a burner. The molten glass produced in the melting step S101 is transported along a predetermined transport path and is subjected to each of the processes in the fining step S102, the homogenization step S103, and the condition adjustment step S104.

[0022] The fining step S102 is a step of degassing the molten glass by the action of a fining agent added to the glass raw material, etc. In the fining step S102, bubbles generated in the molten glass are removed when the molten glass passes through a fining tank arranged downstream of the melting furnace in the conveying path.

[0023] In the homogenization step S103, the molten glass is stirred in a stirring tank disposed downstream of the conveying path from the fining step S102. In the condition adjustment step S104, for example, the viscosity or flow rate of the molten glass is adjusted by a pot disposed downstream of the stirring tank on the conveying path.

[0024] The forming step S2 is a step of forming a long glass ribbon from the molten glass supplied through the glass supplying step S1. In this embodiment, the forming step S2 forms the glass ribbon using a forming body capable of performing, for example, an overflow downdraw method. The forming body is housed in a forming furnace and has a cross-sectional shape that is approximately wedge-shaped. This forming body has an overflow groove in its upper portion.

[0025] The forming body causes the molten glass to overflow from the overflow groove and flow down along the side wall surfaces on both sides of the forming body. The forming body further fuses the flowing molten glass at the lower end of each side wall surface. The width direction end of the molten glass thus fused is gripped by rollers (edge ​​rollers), thereby forming a glass ribbon having a predetermined width. Note that the forming body may be one that performs other downdraw methods such as a slot downdraw method.

[0026] The cooling step S3 includes an annealing step of annealing the glass ribbon formed by the forming body in an annealing furnace, and a cooling step of further cooling the glass ribbon after the annealing step. In the annealing step, the glass ribbon is conveyed downward by conveying rollers arranged in the annealing furnace. A predetermined temperature gradient is set in the annealing furnace, and the glass ribbon is annealed by passing through the annealing furnace. In the cooling step after the annealing step, the glass ribbon passes through a cooling chamber arranged below the annealing furnace while being annealed.

[0027] The cutting step S4 includes a first cutting step and a second cutting step. In the first cutting step, a middle portion of the glass ribbon is cut along the width direction to form a sheet-like glass sheet. That is, in the first cutting step, a scribe line is formed along the width direction in the middle portion of the glass ribbon moving downward, and a part of the glass ribbon is bent and broken along the scribe line to form a sheet-like glass sheet.

[0028] In the second cutting step, the widthwise ends of the glass plate are removed while the glass plate is held in a vertical position, for example. That is, in the second cutting step, in order to cut off the widthwise ends of the glass plate, scribe lines are formed along the up-down direction so as to correspond to each end, and the ends of the glass plate are bent and broken along the scribe lines.

[0029] The first inspection step S5 is a step of inspecting the quality of each glass plate based on defects contained in the glass plate formed in the cutting step S4. As shown in Fig. 3, the first inspection step S5 includes a determination step S51 and an information acquisition step S52.

[0030] In the judgment step S51, image data of the glass plate is acquired by an inspection device while the glass plate is being transported, and the quality of the glass plate is judged based on the image data.

[0031] Specifically, the glass plate is held in a vertical position by a conveying device, and is conveyed by this conveying device so as to pass through the inspection device. The inspection device includes a light source and an imaging device. The inspection device obtains image data by using the imaging device to capture an image of the glass plate passing between the light source and the imaging device. The inspection device detects defects (e.g., protrusions) contained in the image data, and judges the size of the defects based on preset standards. The inspection device determines whether the glass plate is good or bad based on the judgment results.

[0032] The glass plates judged as good in the judgment process S51 are transported to the next packing process S6. Of the glass plates judged as bad in the judgment process S51, some of the glass plates are transferred to the next information acquisition process S52, and the remaining glass plates are discarded (discarding process).

[0033] As shown in FIG. 3, the information acquiring step S52 includes a sample acquiring step S521 and an imaging step S522.

[0034] The sample obtaining step S521 is a step of obtaining a sample for obtaining information on a defect from the glass plate determined to be defective in the determination step S51. In the sample obtaining step S521, a part of the glass plate including the defect detected in the determination step S51 is cut out, and the cut out part becomes the sample.

[0035] In the imaging step S522, data of a magnified image of a defect is obtained from the sample obtained in the sample obtaining step S521 using, for example, an electron microscope or an optical microscope.

[0036] In the information acquisition step S52, information such as the type, size, and depth (depth from the surface of the glass plate) of a defect such as an internal defect (a defect formed inside the glass plate) or a surface defect (a defect formed on the surface of the glass plate) can be acquired from the defect included in the data of the enlarged image acquired in the imaging step S522. In this case, it is preferable to compare the image data acquired by the inspection device in the judgment step S51 with the data of the enlarged image acquired by an electron microscope or the like. The comparison of the image data is performed by visual inspection by an inspector, but is not limited to this embodiment. The comparison of the image data may be performed by a computer capable of machine learning. By comparing the image data, it is possible to acquire information on the defect more accurately and in detail.

[0037] Types of defect information acquired in the information acquisition step S52 include, for example, defects resulting from the glass supplying step S1, defects resulting from the forming step S2, and defects resulting from the cutting step S4.

[0038] Defects caused by the glass supply process S1 are classified into defects caused by the melting process S101, defects caused by the fining process S102, defects caused by the homogenization process S103, and defects caused by the conditioning process S104 through observation based on a comparison between image data of the internal defects of the glass plate acquired by the inspection device in the determination process S51 and image data of the defects acquired in the information acquisition process S52. By observing and comparing these two sets of image data, the inspector can obtain detailed information such as the shape, size, and depth of the defects caused by each of the processes S101 to S104.

[0039] Defects caused by the forming process S2 are also classified into defects caused by the forming process S2 or defects caused by the cooling process S3 by comparative observation based on the image data of the surface defects contained in the glass sheet acquired in the first inspection process S5 and the image data of the defects acquired in the information acquisition process S52. These defects are formed by components contained in the members used in the forming equipment adhering to the glass ribbon. Detailed information such as the shape and size of the defects can be obtained by further observation.

[0040] In addition to the above, various other classifications based on the type of defect are possible, such as classifications based on the shape of the defect, classifications including minute surface foreign matter generated in the cutting step S4, and the like.

[0041] The information acquiring step S52 may acquire defect information from the glass plate judged to be good in the judgment step S51. That is, one or several glass plates judged to be good in the judgment step S51 may be periodically taken out, and the information acquiring step S52 may be carried out on the glass plate in the same manner as described above.

[0042] In the packing step S6, a plurality of glass plates are loaded onto a pallet via protective sheets. The glass plates loaded onto the pallet are then covered with a protective cover or the like. In this way, a package containing a large number of glass plates is formed.

[0043] The transport step S7 is a step of transporting the glass sheet to a processing factory where the processing step S8 is performed. In the transport step S7, the package formed in the packaging step S6 is transported to the processing factory by a transport means such as a transportation vehicle, a railroad car, or a ship.

[0044] The processing step S8 is a step of processing the glass sheet judged to be good in the judgment step S51. As shown in Fig. 1, the processing step S8 includes a second inspection step S81 in which the state of the glass sheet is inspected before or after processing in a processing factory.

[0045] In this second inspection step S81, the shape, surface condition, defect condition, etc. of the glass sheet taken out from the package are inspected. This second inspection step S81 includes an information acquisition step of acquiring characteristic information of the shape, surface condition, and defect condition of the glass sheet judged to be good in the judgment step S51 that is not defective, etc. In this information acquisition step, the characteristic information of the glass sheet is acquired by an inspection device installed in the processing factory.

[0046] In this second inspection step S81, the glass sheet is inspected according to a judgment criterion different from that in the judgment step S51 of the first inspection step S5. In the second inspection step S81, only glass sheets that satisfy this judgment criterion are processed for commercialization.

[0047] The first information providing step S9 is a step of providing (feeding back) information on defects of the glass sheet determined to be defective, acquired by the first inspection step S5, to a step preceding (upstream) the first inspection step S5. In the present embodiment, the first information providing step S9 illustrates a case in which information on defects of the glass sheet determined to be defective is provided to, for example, the glass supplying step S1, the forming step S2, and the cooling step S3, but is not limited thereto, and it is also possible to provide information on defects of the glass sheet determined to be defective to the cutting step S4.

[0048] In the first information providing step S9, when information on defects of glass sheets determined to be defective, acquired in the information acquiring step S52, is related to the glass supplying step S1, this information is provided to the glass supplying step S1. For example, when information on defects of glass sheets determined to be defective is related to the melting step S101, this information is used in the first inspection step S5, and is transmitted from the computer that stores information on defects of glass sheets determined to be defective to the computer used in the melting step S101. The manager of the melting step S101 can use this defect information in making decisions to improve process management in the melting step S101.

[0049] In the first information providing step S9, when information on defects of glass sheets determined to be defective, acquired in the information acquiring step S52, is related to the forming step S2, this information is provided to the forming step S2. For example, when information on defects of glass sheets determined to be defective is related to the forming step S2, this information is used in the first inspection step S5, and is transmitted from the computer that stores information on defects of glass sheets determined to be defective to the computer that manages the forming step S2. The manager of the forming step S2 can use this defect information in making decisions to improve process management in the forming step S2.

[0050] In the first information providing step S9, when information on defects of the glass plate determined to be defective, acquired in the information acquiring step S52, is related to the cutting step S4, this information is provided to the cutting step S4. For example, when the information on the defects of the glass plate determined to be defective includes minute surface foreign matter, this information is used in the first inspection step S5 and is transmitted from the computer storing the information on the defects of the glass plate determined to be defective to the computer managing the cutting step S4. The manager of the cutting step S4 can use this defect information in making decisions to improve the process management in the cutting step S4.

[0051] When the information on the defects of the glass sheet determined to be defective, acquired in the first inspection process S5, includes both information caused by the glass supplying process S1 and information caused by the forming process S2, these pieces of information may be provided simultaneously to the melting process S101 and the forming process S2. Not limited to this, information on the defects of the glass sheet determined to be defective caused only by the glass supplying process S1 may be provided not only to the glass supplying process S1 but also to the forming process S2 and other processes. Moreover, information on the defects of the glass sheet determined to be defective caused only by the forming process S2 may be provided not only to the forming process S2 but also to the glass supplying process S1 and other processes.

[0052] In addition to the above, in the first information provision process S9, if information on defects contained in the glass plate judged to be good in the judgment process S51 is acquired in the information acquisition process S52, the information may be provided to the glass supply process S1, the molding process S2, etc.

[0053] The second information providing step S10 is a step of providing (feeding forward) information on defects of the glass sheet determined to be defective, acquired in the first inspection step S5, to the processing step S8 subsequent to (downstream of) the first inspection step S5. In the second information providing step S10, the information on defects of the glass sheet determined to be defective, acquired in the information acquiring step S52, is used in the first inspection step S5, and is transmitted from the computer storing the defect information to a management computer installed in the processing factory. Based on the received defect information, the manager of the processing step S8 can grasp the tendency of defects contained in the glass sheet determined to be good in the judgment step S51 before processing the glass sheet.

[0054] The third information providing step S11 is a step of providing (feeding back) information on the characteristics of the glass sheet detected in the second inspection step S81 of the processing step S8 to a step before (upstream of) the first inspection step S5, such as the glass supplying step S1 or the forming step S2. In the third information providing step S11, the characteristic information of the glass sheet is transmitted from a computer of the processing factory storing the inspection results of the second inspection step S81 to a computer managing the glass supplying step S1 and a computer managing the forming step S2. Without being limited to this, in the third information providing step S11, the characteristic information of the glass sheet acquired in the second inspection step S81 of the processing step S8 may be provided to the cutting step S4, the first inspection step S5, or other steps.

[0055] According to the glass plate manufacturing method of this embodiment described above, defect information obtained in the information acquisition process S52 from a glass plate determined to be defective in the judgment process S51 of the first inspection process S5 is provided to the glass supply process S1, the forming process S2, etc. in the first information provision process S9, making it possible to utilize this defect information to improve process management in each process.

[0056] The present invention is not limited to the configuration of the above embodiment, nor is it limited to the above-mentioned effects and advantages. Various modifications of the present invention are possible without departing from the spirit and scope of the present invention.

[0057] In the above embodiment, the first information providing step S9 is exemplified to provide information on defects of a glass sheet determined to be defective to the melting step S101 of the glass supplying step S1, but the present invention is not limited to this configuration. In the first information providing step S9, information on defects may be provided to the fining step S102, the homogenizing step S103, or the conditioning step S104.

[0058] In addition, defect information from a glass plate judged to be good in the judgment process S51 may be acquired in an information acquisition process S52, and this information may be provided to the glass supply process S1, the molding process S2, the processing process S8, etc., in a first information provision process S9 and a second information provision process S10.

[0059] In addition, in the above embodiment, if each process from the glass supply process S1 to the first inspection process S5 and the processing process S8 are performed on the same site, the packaging process S6 and the transportation process S7 may be omitted, or only the transportation process S7 may be omitted. [Explanation of symbols]

[0060] S1 Glass supply process S2 Molding process S4 Cutting process S5 First inspection process S51 Judgment process S52 Information acquisition process S521 Sample acquisition process S522 Imaging process S8 Processing process S9 First information provision process S10 Second information provision process S11 Third information provision process

Claims

1. a glass supplying step of supplying molten glass; forming a glass ribbon from the molten glass; a cutting step of cutting the glass ribbon to form sheet-shaped glass plates; An inspection step of inspecting the glass plate, The inspection step includes a determination step of obtaining an image of the glass plate by imaging the glass plate, and determining whether the glass plate is good or bad based on defects included in the image. and an information acquisition step of acquiring information on the defect from the glass plate determined to be defective in the determination step, A method for manufacturing a glass plate, comprising: a first information providing process for providing the information on the defect acquired by the information acquiring process from the glass plate judged to be defective in the judgment process to a process prior to the inspection process.

2. the information acquiring step includes a sample acquiring step of acquiring a sample from the glass plate determined to be defective in the determining step, and an imaging step of acquiring a magnified image of the defect from the sample, The method for manufacturing a glass plate according to claim 1 , wherein in the information acquisition step, the information on the defect is acquired based on the image of the glass plate acquired in the determination step and the enlarged image acquired in the imaging step.

3. a processing step of processing the glass plate judged to be good in the judgment step; The method for manufacturing a glass plate according to claim 1 or 2, further comprising: a second information providing step of providing, to the processing step, the information on the defect acquired from the glass plate judged to be defective in the judgment step by the information acquiring step.

4. In the information acquisition step, characteristic information is acquired from the glass plate judged to be good in the judgment step before or after processing the glass plate in the processing step, The method for manufacturing a glass sheet according to claim 3 , further comprising a third information providing step of providing the characteristic information acquired in the information acquiring step from the glass sheet judged to be good in the judging step to a step preceding the inspection step.

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