JP2010126386A - Method and apparatus for producing glass plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the yield and the quality of a glass plate by making the width of both side parts narrow so that failures such as falling down of an assist roller from the edge of a glass ribbon or the damage of the glass ribbon edge by the assist roller even when not falling down of the assist roller do not occur. <P>SOLUTION: The float type apparatus 10 for producing the glass plate is provided with: a detecting means 40 provided to the subsequent stage of a slow cooling oven 34 and for imaging both side parts of the surface of the glass ribbon to detect the width of rugged mark 36 engraved by pressing of the assist roller 30 and the width of rugged mark outside part 38 ranging from the rugged mark 36 to the edge part 18A of the glass ribbon 18 from the picked-up image; and a control means 42 for controlling factors of a drawing speed of drawing the glass ribbon 18 from a float bath 14, the rotation speed of the assist roller 30, the angle of the assist roller 30, the position of the assist roller 30 and the pressing force of the assist roller to the glass ribbon, on the basis of the determined rugged mark width W3 and the rugged mark outside width W4. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a glass plate manufacturing method and apparatus, and more particularly to online detection of necessary data and a control technique based on the data for improving yield and quality when manufacturing a glass plate.

  In order to manufacture a glass plate, a glass ribbon cast on a molten metal bath (float bath) from a melting furnace is pressed on both sides of a glass ribbon by pressing an assist roll which is a rotating roll with grooves and teeth. A general method is to apply tension in the width direction of the ribbon and draw it into a thin plate by pulling it in the casting direction (traveling direction of the glass ribbon) while preventing the glass ribbon from shrinking in width. The glass ribbon drawn into a thin plate is gradually cooled to room temperature in a slow cooling furnace. Then, both sides of the glass ribbon pressed by the assist roll are cut and removed to form a product width of the glass ribbon.

The edge of the glass ribbon flowing on the float bath is monitored with a surveillance camera, the position of the glass ribbon edge is detected, and the flow rate of the glass substrate supplied from the melting furnace onto the float bath to make the glass ribbon a predetermined width is detected. A control method is known (Patent Document 1).
JP 53-12919 A

  By the way, it is difficult to improve the yield of the glass sheet only by detecting the position of the glass ribbon edge and adjusting the flow rate of the glass substrate supplied from the melting furnace onto the float bath.

  In other words, simply reducing the flow rate of the glass substrate and narrowing the width of the glass ribbon may cause the assist roll to fall off the edge of the glass ribbon, or the glass ribbon edge may be damaged by the assist roll even if it does not fall off. There is a problem that a malfunction such as a failure occurs.

  Therefore, the applicant has intensively studied, and in order to solve the above-mentioned problems, the width of the concave / convex trace engraved on the glass ribbon surface by the assist roll pressing the glass ribbon surface and the edge of the glass ribbon from the concave / convex trace. It was discovered that it was necessary to narrow the both sides of the glass ribbon according to the result of detecting the width of the outside of the traces of irregularities.

  The present invention has been made in view of such circumstances, and the assist roll falls off the edge of the glass ribbon, or the glass ribbon edge is damaged by the assist roll even if it does not fall off. Since both sides of the glass ribbon can be narrowed so as not to occur, an object of the present invention is to provide a glass plate manufacturing method and apparatus capable of improving the yield of the glass plate.

  In order to achieve the above object, the present invention provides a tension in the width direction of the glass ribbon by an assist roll that presses both sides of the surface of the glass ribbon cast on a molten metal float bath. In the apparatus for producing a glass plate, including a float bath that pulls the glass ribbon in the casting direction to form a thin plate while suppressing width reduction, and a slow cooling furnace that slowly cools the thin glass ribbon, It is provided in the latter stage of the slow cooling furnace, images both sides of the surface of the glass ribbon, the width of the uneven traces engraved on the glass ribbon surface by the assist roll from the captured image, and the glass ribbon from the uneven traces A detecting means for detecting the width of the outside of the uneven trace to the edge, and the detecting means is adapted to detect the LED light irradiated on the glass ribbon surface from the projector on the glass surface; Reflective optical system detecting means for detecting the reflected and scattered light to be emitted by a light receiver and detecting the uneven trace width and the outer width of the uneven trace by image processing the detected image by an image processing means, Based on the concave / convex trace width and the concave / convex trace outer width, the drawing speed of drawing out the glass ribbon from the float bath, the rotation speed of the assist roll, the angle of the assist roll, the position of the assist roll, and the glass ribbon pressing force of the assist roll It has the control means which controls one or more.

  Here, the latter stage of the slow cooling furnace means after the glass ribbon comes out of the slow cooling furnace. Moreover, the glass ribbon pressing force of the assist roll refers to, for example, the amount by which the assist roll is pressed down with respect to the glass ribbon on the molten metal. Further, the position of the assist roll refers to the position of the assist roll with respect to the glass ribbon width direction, and the angle of the assist roll refers to the direction of the assist roll with respect to the flow direction of the glass ribbon.

  The assist roll presses the surface of the glass ribbon to capture the uneven traces engraved on the glass ribbon surface, and the image is processed to detect the width pressed by the assist roll as the uneven trace width. To. Moreover, the width | variety of the area | region which the assist roll is not pressing is detected by calculating | requiring the uneven | corrugated trace outer side width from the imaged uneven | corrugated trace to the imaged glass ribbon edge. Thereby, the data of the uneven trace width and the uneven trace outer width can be easily obtained.

  Then, based on the detected uneven trace width and uneven trace outer width, the drawing speed for pulling out the glass ribbon from the float bath, the rotation speed of the assist roll, the angle of the assist roll, the position of the assist roll, and the glass ribbon pressing force of the assist roll These five control factors can be controlled.

  The control may be performed manually by an operator, and the five control factors are automatically controlled so that the fluctuation allowable width between the concave / convex trace width and the concave / convex trace outer width is set in advance and is not deviated from the fluctuation allowable width. You may do it.

  As a result, the width of the both sides of the glass ribbon is reduced without causing problems such as the assist roll falling off from the edge of the glass ribbon or the glass ribbon edge being damaged by the assist roll even if it does not fall off. Therefore, the yield can be improved.

  Here, both sides of the glass ribbon refer to portions outside the product width W2 of the glass ribbon. That is, it refers to a portion of the width W5 that combines the concave / convex trace width W3, the concave / convex trace outer width W4, and the concave / convex trace inner width W6 (width from the concave / convex trace to the product width position of the glass ribbon).

  The detection means may use laser light as a light source, but the laser light needs to be scanned with a narrow irradiation width, and the apparatus becomes large and the laser is vulnerable to vibration. The present invention employs a reflection optical system detection means that uses LED light that does not require scan scanning and is resistant to shake and a sudden change in glass ribbon width.

  In the present invention, the detection means detects the transmitted light that has been irradiated from the projector and transmitted through the glass ribbon with a light receiver, and the detected image is processed by the image processing means, whereby the concave / convex trace width and the concave / convex trace outer side are detected. It is preferable to use a transmission optical system detection means for detecting the width in combination.

  In combination with the detection of the concave / convex trace width and the concave / convex trace outer width by the reflective optical system detection means, the transmission optical system detection means also detects the concave / convex trace width and the concave / convex trace outer width, and collates both to detect Reliability can be improved. The transmission optical system detection means can easily detect a dot-like tooth profile mark in which the teeth of the assist roll bite into the surface of the glass ribbon.

  In the present invention, the detection means is preferably provided at a position where the temperature of the detection atmosphere is not lower than room temperature and not higher than 100 ° C. in terms of detection accuracy.

  In order to achieve the above object, the present invention provides a tension in the width direction of the glass ribbon by an assist roll that presses both sides of the surface of the glass ribbon cast on a molten metal float bath. In a method for producing a glass plate, including a step of pulling the glass ribbon in the casting direction into a thin plate while suppressing width reduction, and a step of gradually cooling the thin glass ribbon in a slow cooling furnace, It has a detection step of detecting the width of the concave and convex traces engraved on the glass ribbon surface by pressing the assist roll and the width of the concave and convex trace outside from the concave and convex traces to the edge of the glass ribbon, By detecting reflected / scattered light reflected from the glass surface by the LED light irradiated on the glass ribbon surface from the projector using a light receiver, and processing the detected image, the uneven mark A reflection optical system detection step for detecting a width and the outer width of the concave / convex trace, and the concave / convex trace width and the outer width of the concave / convex trace are maintained at a predetermined width based on the detected width of the concave / convex trace and the outer width of the concave / convex trace. A control step of controlling one or more of a drawing speed for pulling out the glass ribbon from the float bath, a rotation speed of the assist roll, an angle of the assist roll, a position of the assist roll, and a glass ribbon pressing force of the assist roll. It is characterized by that.

  The pulling speed of the glass ribbon, the rotation speed of the assist roll, the rotation speed of the assist roll is adjusted so that the uneven trace width and the uneven trace outer width are maintained at a predetermined width based on the detected uneven trace width and the uneven trace outer width. By controlling one or more of the angle, the position of the assist roll, and the glass ribbon pressing force of the assist roll, the glass ribbon edge is supported by the assist roll even if the assist roll falls off from the edge of the glass ribbon. Thus, the width of both sides of the glass ribbon can be reduced without causing problems such as damage. Thereby, a yield improvement can be aimed at.

  It should be noted that the number of the predetermined widths of the uneven trace width and the uneven trace outer width depends on the type of glass plate to be manufactured, the thickness of the glass plate, etc., so that the assist roll may fall off from the edge of the glass ribbon or drop off. Even if it is not, the set values of the concave / convex trace width and the concave / convex trace outer width may be obtained in advance by a preliminary test or the like so as not to cause problems such as breakage of the glass ribbon edge by the assist roll.

  The control may be performed manually by an operator. One of the five control factors is set so that a variation allowable width between the concave / convex trace width and the concave / convex trace outer width is set in advance and does not deviate from the variation allowable width. Two or more may be automatically controlled.

  The detecting step detects reflected / scattered light reflected from the glass surface by the LED light irradiated on the glass ribbon surface from the projector with a light receiver, and processes the detected image to thereby process the uneven trace width and the uneven trace. This is a reflection optical system detection step for detecting the outer width.

  Further, in the detection step, transmitted light that is irradiated from a projector and transmitted through the glass ribbon is detected by a light receiver, and the detected trace width and the outer width of the projected trace are detected by performing image processing on the detected image. By using the optical system detection step in combination, the detection reliability can be further improved.

  According to the method and apparatus for producing a glass plate of the present invention, the assist roll is not dropped from the edge of the glass ribbon, or the glass ribbon edge is not damaged by the assist roll even if it is not dropped. Thus, since both sides of the glass ribbon can be narrowed, the yield of the glass plate can be improved.

  Hereinafter, preferred embodiments of a method and apparatus for producing a glass sheet according to the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to these embodiments.

  FIG. 1 is a conceptual diagram showing an example of a glass plate manufacturing apparatus 10 of the present invention from above.

  As shown in FIG. 1, molten glass is supplied from a melting furnace 12 onto a molten metal 16 in a float bath 14. As the molten metal, tin is generally used. The supplied molten glass forms the glass ribbon 18 on the upstream side of the float bath, and the assist roll 30 applies a tension toward the outer side in the width direction to the glass ribbon 18 to form a target glass plate thickness.

  As shown in the partially enlarged view of FIG. 1, the assist roll 30 presses both side portions of the surface of the glass ribbon 18, and the rotation shafts 32 of the assist roll 30 forming a pair are expanded in a letter C shape. .

  As shown in FIGS. 2A and 2B, uneven traces 36 pressed by the plurality of assist rolls 30 are formed in the traveling direction of the glass ribbon 18 on both sides of the glass ribbon surface.

  As shown in FIG. 1, the glass ribbon 18 formed to a target glass thickness in the float bath 14 is drawn out from the molten metal bath surface by the lift-out roll 20, and is conveyed by the slow cooling roll 26 in the slow cooling furnace 34. And gradually cooled to a temperature close to room temperature.

  In the production of such a glass plate, it is possible to contribute to an increase in yield by narrowing the concave / convex trace outer width W4. However, if the width is too narrow, the assist roll 30 may or may not fall off from the edge 18A of the glass ribbon 18. In addition, the glass ribbon edge 18A is likely to be damaged by the assist roll 30. Thereby, the malfunction that a glass plate cannot be manufactured stably generate | occur | produces.

  Moreover, if the uneven | corrugated trace width W3 of the glass ribbon 18 becomes too narrow, the assist roll 30 will bite into the uneven | corrugated trace 36 part intensively. As a result, the assist roll 30 can easily break through the glass ribbon 18. Further, residual strain is generated and the glass ribbon 18 is likely to warp. Furthermore, the glass ribbon 18 is easily damaged in the slow cooling furnace 34.

  Therefore, in the present invention, the detection means 40 for detecting the concave / convex trace width W3 and the concave / convex trace outer width W4 and the detection of the concave / convex trace width W3 and the concave / convex trace outer width W4 detected by the detection means 40 are provided downstream of the slow cooling furnace 34. Based on the data, the five control factors of the drawing speed for pulling the glass ribbon out of the float bath 14, the rotation speed of the assist roll 30, the angle of the assist roll 30, the position of the assist roll 30, and the pressing force of the glass ribbon of the assist roll 30 are appropriate. The control means 42 for controlling is provided. Thereby, the said malfunction is prevented.

  Note that the detection means 40 may be provided in the slow cooling furnace 34 as long as a detection atmosphere of 100 ° C. or less can be secured.

  Next, details of the detection means 40 will be described.

  FIG. 3A shows a detection means 40 for detecting the right side of the glass ribbon 18 as viewed from the traveling direction, and the same is provided on the left side of the traveling direction.

  The detection means 40 is mainly composed of a reflection optical system device 44 composed of a projector 44A and a light receiver 44B, an image processing device 46, and a display device 48, and a detection region in both sides of the glass ribbon surface from the projector 44A. The detection region 49 is imaged by receiving the specularly reflected light irradiated on the light 49 with the light receiver 44B. An LED light source can be preferably used as the projector 44A, and a CCD area sensor can be preferably used as the light receiver 44B. The light source may be a fiber light source using light sources other than LEDs, but an LED light source is preferable in consideration of the use environment (atmosphere of 100 ° C. or less, etc.).

  In order to perform real-time control, it is preferable to set the number of times of imaging by the light receiver 44B to 1 minute or less. The detection area 49 is an area including both sides of the glass ribbon.

  Hereinafter, a method of calculating the uneven trace width W3 and the uneven trace outer width W4 by the image processing device 46 will be described with reference to the step flow diagram of FIG.

  In step 1, the specularly reflected light emitted from the light projector 44A of the reflective optical system device 44 is received by the light receiver 44B, and an image of the detection region 49 is collected. The reflection optical system device 44 is configured to be movable in the width direction of the glass ribbon 18, and thereby takes an image over the width direction of the glass ribbon 18 in the detection region 49 (FIG. 3).

  In step 2, the collected image is converted into an electrical signal and input to the image processing device 46, and binarization processing is performed on the designated region 51 corresponding to the glass ribbon width direction in the collected image. The designated area 51 is preferably about 640 pixels (1 pixel: 0.25 mm) in width in the traveling direction of the glass ribbon 18.

  FIG. 5A is a diagram for explaining the binarization process in step 2, where the Y axis indicates the magnitude of the luminance, and the X axis indicates the position in the width direction of the glass ribbon 18. The threshold value setting for the binarization process employs an intermediate value method, in which the luminance between the highest luminance and the lowest luminance is set as a threshold, pixels having a luminance higher than the threshold are set to 1 (white), and pixels having a lower luminance are set to 0 (black). ) To obtain a binarized image.

  Next, in step 3, noise removal processing for removing noise from the binarized image is performed. In the noise removal, black (0) or white (1) of a pixel of interest is compared with black (0) or white (1) of a pixel located above, below, left and right of the pixel of interest, so that the pixel of interest is an image. It is preferable to adopt a four-connection method for determining whether the noise is noise. Thereby, noise is removed. Note that the 8-connection method can be adopted, but the 4-connection method can shorten the time for noise removal processing.

  Next, in step 4, a labeling process is performed. The label processing is a method of labeling adjacent black (0) pixels and adjacent white (1) pixels as one block.

  Next, in step 5, a lump having an area smaller than a preset lump area threshold is removed as an unnecessary label. Unnecessary labels are also removed from chunks that deviate from the designated area 51.

  Next, in step 6, center point sequence processing is performed. As shown in FIG. 5 (B), the center point sequence processing calculates a Y coordinate center point B for each of a plurality of labeled labels A, and the center points B are lined up as shown in FIG. 5 (C). Connect with. Thereby, as shown to FIG. 3 (B), the pattern (henceforth an uneven | corrugated pattern diagram) which shows the uneven | corrugated trace of the assist roll 30, and the glass surface state of the outer side and inner side is obtained. Note that FIG. 3B is illustrated for easy understanding. Then, the uneven pattern diagram is displayed on the display device 48.

  Next, in Steps 7 to 14, using the obtained uneven pattern diagram, the edge 18 A of the glass ribbon 18, the outer end of the uneven trace 36 and the inner end of the uneven trace 36 are obtained, and the uneven trace width W 3 and the uneven trace are obtained. The outer width W4 is calculated.

  First, in step 7, subdivision processing is performed. That is, as shown in FIG. 6A, the concavo-convex pattern diagram is set to a predetermined section length (for example, 5 mm) at a predetermined interval (for example, 2.5 mm interval) from the edge 18A side of the glass ribbon 18, that is, It subdivides into the number of sections of A [i] (i = 0, 1, 2,... N).

  Next, in step 8, it is determined by the least square method whether or not the line existing in each subdivided section can be regarded as a straight line in the concave / convex scar outer side determination process corresponding to the concave / convex trace outer width W4. 6A, it is determined whether or not each section is a straight line from the left end of the uneven pattern diagram, that is, the edge 18A side of the glass ribbon 18. For example, a straight line section of 10 mm or more is continuous. Is recognized as an outer portion of the concave / convex trace, and is defined as a linear type L1 (see FIG. 6B).

  Next, in step 9, as in the case of step 8, the inner part determination process corresponding to the inner width of the concave / convex trace is performed. This is to determine whether the line existing in each section subdivided from the right end of the uneven pattern diagram in FIG. 6A, that is, from the center side of the glass ribbon 18, can be regarded as a straight line, For example, a portion in which straight sections of 10 mm or more are continuous is recognized as the inner side of the concave / convex trace, and is defined as a linear formula L2 (see FIG. 6B).

  Next, in step 10, a determination process for the position of the edge 18 </ b> A of the glass ribbon 18 is performed. That is, the image coordinates obtained by adding the R value of the edge 18A (a preset edge curvature radius) to the image coordinates at the left end of the linear expression L1 are determined as the position of the edge 18A.

  Next, in step 11, determination processing of the outer edge of the uneven trace 36 is performed. That is, as shown in FIG. 6C, the height difference Δ between the extension line a obtained by extending the linear expression L1 in the right direction and the concavo-convex pattern diagram is obtained. Then, when the number of times that the difference Δ becomes a value (Dj) larger than a preset predetermined value K occurs continuously for a preset predetermined number M or more, the uneven pattern diagram deviates from the linear expression L1. , Dj is recognized as the outer end of the uneven trace 36.

  Next, in step 12, as in step 11, the inner edge determination process of the uneven trace 36 is performed.

  Next, in steps 13 and 14, from the obtained image coordinates of the edge 18A position, image coordinates of the outer end of the uneven trace 36, and image coordinates of the inner end of the uneven trace 36, the uneven trace width W3 and the uneven trace outer width W4 is calculated. Note that the magnification relationship between the image coordinates and the apparatus coordinates of the glass plate manufacturing apparatus 10 is obtained in advance.

  Thereby, the data of the concave / convex trace width W3 and the concave / convex trace outer width W4 can be obtained online, and the obtained data is sequentially input to the control means 42. Based on the obtained data of the concave / convex trace width W3 and the concave / convex trace outer width W4, the control means 42 controls the glass ribbon 18 so that each of the concave / convex trace width W3 and the concave / convex trace outer width W4 is maintained at a predetermined width. 50A for varying the rotational speed of the lift-out roll 20 and the slow cooling roll 26 for varying the speed at which the air is drawn from the float bath 14, the driving section 50B for varying the rotational speed of the assist roll 30, and the roll angle of the assist roll 30 One or more of the five control factors (see FIG. 1) of the drive unit 50C that changes the roll, the drive unit 50D that changes the roll position of the assist roll 30, and the drive unit 50E that changes the glass ribbon pressing force of the assist roll 30 Control part. In addition, based on the data of the uneven | corrugated trace width W3 detected by the detection means 40 and the uneven | corrugated trace outer width W4, an operator may set the said 5 control factors appropriately manually.

  The number of predetermined widths in the concave / convex trace width W3 and the concave / convex trace outer width W4 varies depending on the type of glass plate to be manufactured, the thickness of the glass plate, and the like, so the assist roll 30 falls off the edge 18A of the glass ribbon 18. Even if the glass ribbon edge 18A is broken by the assist roll 30 even if it does not fall off, the set values of the concave / convex trace width W3 and the concave / convex trace outer width W4 may be provided in advance. .

  Thereby, since the width W5 of both sides of the glass ribbon can be narrowed without causing problems such as the drop off of the assist roll 30 or the breakage of the glass ribbon edge 18A, the yield can be improved.

  In the embodiment of the present invention, only the detection means 40 of the reflection optical system is shown as the detection means, but the detection reliability is improved by using the detection means of the transmission optical system together and collating the detection results. Can be made.

  FIG. 7A is a conceptual diagram of a transmission optical system device 60 as a detection unit of the transmission optical system, and FIG. 7B is a schematic diagram of an image obtained by the transmission optical system device 60.

  As shown in FIG. 7A, the transmitted light transmitted through the glass ribbon 18 from the projector 60A provided below the glass ribbon 18 is detected by the light receiver 60B provided above the glass ribbon 18 to obtain an image. . As a result, in the transmission optical system device 60, an image is formed as a line row 31 in which the teeth of the assist roll 30 are connected to the dot-like tooth profile marks that have digged into the surface of the glass ribbon 18. In this case, the line row 31 can be clarified by disposing the screen 64 (ground glass) between the glass ribbon 18 and the projector 60A. Therefore, the uneven trace width W3 from the left end to the right end of the line row 31 in FIG. 7B is the uneven trace outer width W4 from the edge 18A of the glass ribbon 18 to the left end of the line row 31. That is, the values of W3 and W4 are obtained as in the case of the reflective optical system.

  Next, examples of the present invention will be described.

  As shown in FIG. 1, molten glass is supplied onto a melting furnace 12 float bath 14 and formed into a glass ribbon 18 having a predetermined thickness. Next, after the glass ribbon 18 is gradually cooled to near room temperature in the slow cooling furnace 34, the inner side of the glass ribbon surface is imaged by the reflective optical system device 44, and the concave / convex trace width W 3 and the concave / convex trace outer width W 4 by the image processing device 46. Is detected.

  Next, the glass ribbon 18 is floated so that each of the concave / convex trace width W3 and the concave / convex trace outer width W4 is maintained at a predetermined width based on the obtained concave / convex trace width W3 and concave / convex trace outer width W4 data. One or more of the speed pulled out from the bus 14, the rotation speed of the assist roll 30, the roll angle of the assist roll 30, the roll position of the assist roll 30, and the glass ribbon pressing force of the assist roll 30 are controlled.

  Thus, both sides of the glass ribbon can be narrowed without causing problems such as the assist roll 30 falling off the edge 18A of the glass ribbon 18 or the glass ribbon edge 18A being damaged by the assist roll 30. The yield of the glass plate is improved.

  Furthermore, in addition to the detection means 40 of the reflection optical system, the detection means of the transmission optical system is used in combination as the detection means for detecting the uneven trace 36 and the outer portion of the uneven trace. As a result, detection reliability is improved.

The conceptual diagram which expands and shows the whole structure of the manufacturing apparatus of the glass plate of this invention, and the part which the assist roll is pressing the glass ribbon. It is explanatory drawing mainly explaining the uneven | corrugated trace of the width direction formed in a glass ribbon. It is a conceptual diagram of the detection means of the reflective optical system of an uneven | corrugated trace width and an uneven | corrugated trace outer width. It is a step flow diagram of image processing. 5A is an explanatory diagram for explaining binarization processing by the center point method in image processing, FIG. 5B is an explanatory diagram for explaining center point sequence processing in image processing, and FIG. 5C is a center point. It is the figure which connected the center point by which the row | line | column process was carried out with the line. FIG. 6A is an explanatory diagram for explaining the segmentation process in the image processing, FIG. 6B is an explanatory diagram for explaining the determination process for the outer portion of the uneven trace in the image processing, and FIG. 6C is an unevenness in the image processing. Explanatory drawing explaining the determination process of a trace edge Conceptual diagram of transmission optical system device and schematic diagram of obtained image

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Glass plate manufacturing apparatus, 12 ... Melting furnace, 14 ... Float bath, 16 ... Molten metal, 18 ... Glass ribbon, 20 ... Lift-out roll, 26 ... Slow cooling roll, 30 ... Assist roll, 32 ... Assist roll Rotation axis 36 ... concave / convex trace, 38 ... concave / convex trace outer side, 40 ... detection means, 42 ... control means, 44 ... reflection optical system device, 44A ... projector, 44B ... light receiver, 46 ... image processing device, 48 ... display Device: 60 ... Transmission type optical system device, 60A projector, 60B ... Light receiver

Claims (4)

The glass ribbon is restrained from being reduced in width by applying tension in the width direction of the glass ribbon by an assist roll that presses both sides of the surface of the glass ribbon cast on a molten metal float bath. In a glass plate manufacturing apparatus, including a float bath that is pulled in the casting direction to form a thin plate, and a slow cooling furnace that slowly cools the thin glass ribbon,
Provided in the subsequent stage of the slow cooling furnace, image both sides of the surface of the glass ribbon, and from the captured image, the width of the uneven marks engraved on the glass ribbon surface by the assist roll, and the glass ribbon from the uneven marks A detecting means for detecting the width outside the concave and convex traces to the edge of the LED, the detecting means detects reflected and scattered light reflected from the glass surface by the LED light irradiated from the projector to the glass ribbon surface, It is a reflection optical system detection means for detecting the uneven trace width and the uneven trace outer width by image processing the detected image by an image processing means,
Based on the detected concave / convex trace width and concave / convex trace outer width, the drawing speed of pulling out the glass ribbon from the float bath, the assist roll rotation speed, the assist roll angle, the assist roll position, and the assist roll glass ribbon pressing An apparatus for producing a glass plate, comprising control means for controlling one or more of the pressures.   The detection means detects transmitted light that has been irradiated from the projector and transmitted through the glass ribbon with a light receiver, and detects the uneven trace width and the uneven trace outer width by performing image processing on the detected image with the image processing means. The apparatus for producing a glass plate according to claim 1, wherein a transmission optical system detection means is used in combination. The glass ribbon is restrained from being reduced in width by applying tension in the width direction of the glass ribbon by an assist roll that presses both sides of the surface of the glass ribbon cast on a molten metal float bath. In the method for producing a glass plate, comprising a step of pulling in the casting direction to form a thin plate, and a step of gradually cooling the thinned glass ribbon in a slow cooling furnace,
It has a detection step of detecting the width of the concave and convex traces engraved on the glass ribbon surface by pressing the assist roll and the width of the concave and convex trace outside from the concave and convex traces to the edge of the glass ribbon, Reflection that detects reflected and scattered light reflected on the glass surface by the LED light irradiated on the glass ribbon surface from the projector with a light receiver, and detects the uneven trace width and the uneven trace outer width by image processing the detected image. Optical system detection process,
Based on the detected concave / convex trace width and concave / convex trace outer width, the pulling speed for pulling out the glass ribbon from the float bath and the rotation speed of the assist roll so that the concave / convex trace width and the concave / convex trace outer width are maintained at a predetermined width. A method for producing a glass plate, comprising a control step of controlling one or more of an assist roll angle, an assist roll position, and a glass ribbon pressing force of the assist roll.   The detection step detects transmitted light that has been irradiated from the projector and transmitted through the glass ribbon, and detects the undulation trace width and the undulation trace outer width by performing image processing on the detected image. The method for producing a glass plate according to claim 3, wherein the steps are used in combination.

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