JP2020066548A - Analysis device, manufacturing apparatus of float glass, analysis method, and manufacturing method of float glass - Google Patents

Abstract

To provide an analysis device, a manufacturing apparatus of float glass, an analysis method, and a manufacturing method of float glass that are able to reduce plate thickness deviation of a glass substrate by suppressing fluctuation in a width direction of a glass ribbon in a float bath.SOLUTION: A manufacturing apparatus 1 of float glass is equipped with a melting furnace 10, a float bath 20, an annealing furnace 30, and an analysis device 40. A plurality of pairs of top rolls 50 are arranged in the float bath 20. The top roll 50 has a plurality of protrusions 52 on the outer periphery of the tip 51 in contact with a glass ribbon 22, and forms recesses T at intervals along a flow direction on the glass ribbon 22. A photographing unit 41 of the analysis device 40 takes a picture of the recesses T of which locations and intervals are calculated by an image processing and identification unit 42 to specify the top roll 50 causing a fluctuation in plate thickness deviation.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an analysis device, a float glass manufacturing device, an analysis method, and a float glass manufacturing method.

  The plate thickness deviation in the entire surface of the glass substrate for a flat panel display (FPD) affects the defocus of the exposure device in the photolithography process. The glass substrate for FPD, especially the glass substrate for liquid crystal display (LCD), has a strict requirement for the plate thickness deviation, and is required to be 20 μm or less in a range of 1500 mm, for example. The plate thickness deviation is a difference between the maximum plate thickness and the minimum plate thickness.

  As a method of reducing the plate thickness deviation, in Patent Document 1, the heater area of the float bath is divided in the flow direction and the width direction of the glass ribbon, a plurality of heaters are provided in each division, and a plurality of heaters are controlled for each division. The technology to do is proposed.

JP, 2011-225386, A

  However, even if the technique of Patent Document 1 is adopted, if the glass ribbon in the float bath varies in the width direction, there is a problem that the thickness of the glass ribbon varies and, consequently, the plate thickness deviation of the glass substrate increases. The variation in the width direction of the glass ribbon may cause a problem that the requirement for the plate thickness deviation cannot be satisfied.

  The present invention has been made in view of the above problems, by suppressing the variation in the width direction of the glass ribbon in the float bath, an analyzer capable of reducing the plate thickness deviation of the glass substrate, The main purpose is to provide a float glass manufacturing apparatus, an analysis method, and a float glass manufacturing method.

  The analysis apparatus of the present invention includes a float bath for forming molten glass continuously supplied onto molten metal into a glass ribbon while flowing on the molten metal, and a slow cooling furnace for gradually cooling while transporting the glass ribbon by a layer roll. It is applied to a float glass manufacturing apparatus comprising, and an analyzer for analyzing a plurality of concave portions formed on both side portions in the width direction of the glass ribbon, wherein the float bath has a space along the flow direction of the glass ribbon. With a plurality of pairs of top rolls provided with a space, the top roll has a plurality of protrusions on the outer periphery of the tip end portion that comes into contact with the glass ribbon, and supports both side portions in the width direction of the glass ribbon. The imaging device forms the recesses at intervals along the flow direction, and the analyzer analyzes the width of the glass ribbon in both width direction. Image processing identification for detecting the position of the concave portion after performing image processing on the inspection image, and for identifying the top roll having the concave portion having the predetermined distance based on the distance between the concave portions in the flow direction. And a section.

  The float glass manufacturing apparatus of the present invention is a float glass manufacturing apparatus equipped with the analysis device, wherein the amount of the glass ribbon withdrawn per day on the layer roll is based on the change over time in the identified position of the recess. Conveyance speed of the glass ribbon, rotation speed of the tip portion, angle formed by the tip portion in a plan view with the conveyance direction of the glass ribbon, position of the tip portion in plan view, and position of the tip portion in the vertical direction. Control one or more of them.

  The analysis method of the present invention includes a float bath that forms molten glass continuously supplied onto a molten metal into a glass ribbon while flowing on the molten metal, and a slow cooling furnace that gradually cools while transporting the glass ribbon by a layer roll. A method for analyzing a plurality of recesses formed on both side portions in the width direction of the glass ribbon, which is applied to a float glass manufacturing apparatus including, wherein the float bath has a space along a flow direction of the glass ribbon. With a plurality of pairs of top rolls provided with a space, the top roll has a plurality of protrusions on the outer periphery of the tip end portion that comes into contact with the glass ribbon, and supports both side portions in the width direction of the glass ribbon. Forming the recesses at intervals along the flow direction, and the analyzing method includes a step of imaging both side portions in the width direction of the glass ribbon, and the imaged inspection Image-processing the image, detecting the position of the recesses, and based on the spacing between the recesses in the flow direction, identifying the top roll having the recesses having the predetermined spacing. .

  The float glass manufacturing method of the present invention is a float glass manufacturing method using the analysis method, wherein the drawn amount of the glass ribbon per day on the layer roll is based on the change with time of the identified position of the recess. Conveyance speed of the glass ribbon, rotation speed of the tip portion, angle formed by the tip portion in a plan view with the conveyance direction of the glass ribbon, position of the tip portion in plan view, and position of the tip portion in the vertical direction. Control one or more of them.

  According to the present invention, by analyzing the recesses on the glass ribbon, it is possible to identify the top roll that causes the thickness deviation, and thus it is possible to provide a glass substrate having an accurate thickness.

The conceptual diagram which shows an example of the float glass manufacturing apparatus which concerns on this invention. The relationship between the top roll and the glass ribbon in this invention is shown, (a) The conceptual diagram from a side surface, (b) The conceptual diagram from a plane view, (c) The conceptual diagram from a front. The conceptual diagram which shows the top roll and recessed part in this invention. The conceptual diagram which shows another embodiment of the top roll in this invention. FIG. 4 is a conceptual diagram showing an example of another embodiment of the image pickup unit in the present invention, (a) a conceptual diagram of the image pickup unit of the transmission optical system, and (b) a schematic diagram of an image obtained by the image pickup unit of the transmission optical system.

  Hereinafter, specific embodiments of an analysis apparatus, a float glass manufacturing apparatus, an analysis method, and a float glass manufacturing method according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a conceptual diagram showing an example of the float glass manufacturing apparatus of this embodiment. 2A and 2B show the relationship between the top roll and the glass ribbon. FIG. 2A is a conceptual view from a side surface, and FIG. 2B is a conceptual view from a plan view. FIG. 3 is a conceptual diagram showing the top roll and the recess. The float glass manufacturing apparatus of this embodiment will be described based on FIGS. 1 to 3.

  The float glass manufacturing apparatus 1 of the present embodiment includes a melting furnace 10, a float bath 20, an annealing furnace 30, and an analyzing device 40. In the float bath 20, a plurality of pairs of top rolls 50 are arranged on the molten metal 21 made of tin or the like, and in the annealing furnace 30, a plurality of layer rolls 31 are arranged.

  Molten glass is supplied from the melting furnace 10 onto the molten metal 21 inside the float bath 20, and the molten glass is formed on the glass ribbon 22 while flowing on the molten metal 21. In addition, when the molten glass is supplied from the melting furnace 10 to the float bath 20, the opening amount is controlled by the twill 11 that moves up and down to control the supply amount. In the present embodiment, the pair of monitoring cameras 71 images the vicinity of the edge of the molten glass (glass ribbon 22) in the float bath 20 through the viewing window provided in the float bath 20 and monitors the supply amount. .

  The glass ribbons 22 in the float bath 20 are provided along the flow direction of the glass ribbons 22 with a space between them, and a plurality of pairs of top rolls 50 that support the widthwise side portions 23 of the glass ribbons 22 allow the glass ribbons 22 to move. Tension oriented in the width direction is applied.

  The respective top rolls 50 are arranged opposite to each other on both side portions 23 in the width direction of the glass ribbon 22 to form a pair. The rotation of the top roll 50 sends the glass ribbon 22 to the downstream side, and the width of the glass ribbon 22 has a surface tension. To prevent narrowing.

  The number of the top rolls 50 installed is appropriately set according to the molding conditions such as the type of glass and the target thickness, but is, for example, 4 to 30 pairs, preferably 10 to 30 pairs. As the target thickness of the glass substrate becomes thinner, the number of top rolls installed tends to increase.

  The glass ribbon 22 formed in the float bath 20 to have a predetermined plate thickness is pulled out from the bath surface of the molten metal 21 by a lift-out roll 32 arranged between the float bath 20 and the slow cooling furnace 30, and a layer roll in the slow cooling furnace 30. It is transported at 31 and gradually cooled to a temperature close to room temperature. The glass ribbon after the gradual cooling is cut into a desired size by a cutting device to form a glass substrate.

  As shown in FIG. 2, the top roll 50 has a rotary shaft 53 supported by an external member (not shown), and a distal end portion 51 rotatably attached to the distal end of the rotary shaft 53 and in contact with the glass ribbon 22. The tip portion 51 is a circular rotating body, and a plurality of protrusions 52 having a predetermined interval in the circumferential direction are provided on the outer periphery of the tip portion 51. Therefore, when the tip portion 51 rotates, the plurality of protrusions 52 on the outer periphery form the recesses T on the glass ribbon 22 at intervals along the flow direction of the glass ribbon 22. Further, the rotational speed V of the tip end portion 51 of the top roll 50, the angle θ formed by the tip end portion 51 in plan view with the conveying direction (flow direction) of the glass ribbon 22, the position of the tip end portion 51 in plan view, and the tip end portion in the vertical direction. The position of 51 is controlled.

  In such a float glass production, it is possible to reduce the plate thickness deviation of the glass ribbon 22 by suppressing the fluctuation of the glass ribbon 22 in the width direction. However, when the plate thickness deviation fluctuates, a plurality of pairs of tops are formed. Of the rolls 50, it is not easy to determine which top roll 50 is responsible for the fluctuation.

  Therefore, in the float glass manufacturing apparatus 1 of the present embodiment, an analysis device 40 for analyzing the recess T is provided at the subsequent stage of the annealing furnace 30. The analysis device 40 performs image processing on the image capturing unit 41 that captures both widthwise side portions 23 of the glass ribbon 22 and the inspection image captured by the image capturing unit 41, detects the position of the recess T, and detects the recess T in the flow direction. An image processing identification unit 42 for identifying the top roll 50 having the recessed portion T having a predetermined interval based on the interval therebetween, and a display unit 43 for displaying an inspection image are provided.

  The analysis device 40 is electrically connected to the control unit 60, and the control unit 60 drives the rotation of the liftout roll 32 and the layer roll 31 based on the analysis result of the image processing identification unit 42. 62 and the drive unit 61 that drives the rotation of the top roll 50 are controlled.

  The analysis device 40 may be provided in the slow cooling furnace 30 as long as an analysis atmosphere of 100 ° C. or lower can be secured.

  As described above, in the float glass manufacturing apparatus 1, a plurality of pairs of top rolls 50 are installed along the flow direction of the glass ribbon 22, and the rotation speed V of each top roll 50 is different. FIG. 3 shows three top rolls 501, 502, 503 installed in order from the upstream side to the downstream side. Note that, in FIG. 3, the top rolls 501, 502, and 503 are provided from the outer side to the inner side in the width direction from the upstream side to the downstream side, but the present invention is not limited thereto. For example, the top roll 503 may be provided inside the top roll 501 in the width direction and outside the top roll 502.

  The rotation speed V of the tip end portion 51 of the downstream side top roll 50 is higher than that of the upstream side, and in the example of FIG. 3, the rotation speed of the top roll 501 <the rotation speed of the top roll 502 <the rotation of the top roll 503. It will be speed. From such a relationship of the rotation speed, for the recess T1 of the top roll 501, the recess T2 of the top roll 502, and the recess T3 of the top roll 503, the interval between the recesses T1> the interval between the recesses T2> the interval between the recesses T3 is satisfied. It is understood that the relationship is established.

  In view of the above-mentioned circumstances, the inventor has devised a mathematical formula in order to confirm whether or not the corresponding top roll 50 can be specified from the interval between the concave portions T imaged by the imaging unit 41, and calculates the theoretical value based on the mathematical formula. The relationship between the measured values was investigated.

  According to the mathematical expression, the distance D between the protrusions 52 in the circumferential direction of the tip portion 51 shown in FIG. 2C is multiplied by the conveyance speed L of the glass ribbon 22 on the layer roll 31, and the rotation speed V of the tip portion 51 is calculated. The value calculated by dividing is the interval between the recesses T (blade mark interval). That is, the blade trace interval = D × L / V.

The theoretical value of the distance between the recesses T was calculated based on the above equation, and the actual measurement value was measured. The measured value is the distance between the concave portions T formed by the top rolls provided in the region where the viscosity of the glass ribbon is 10 ^5.3 dPa · s or more among the top rolls, and there is a correlation between the theoretical value and the measured value. I was able to determine that there was. Then, by programming the correlation, the image processing identification unit 42 compares the value calculated by the above equation with the interval (measured value) between the recesses T in the flow direction, and the recess T closest to the calculated value is compared. The top roll 50 in which the concave portion T having the interval (actual measurement value) is formed can be identified as the top roll 50 having the tip end portion 51 having the rotation speed V.

  Since the image capturing unit 41 captures the widthwise both sides 23 of the glass ribbon 22, the image processing identifying unit 42 can detect the positions of the widthwise both ends 24 of the glass ribbon 22, and the fluctuation of the glass ribbon 22 can be detected. You can figure it out.

  As shown in FIG. 3, the imaging unit 41 may be an optical device including a light projector 41a and a light receiver 41b. By receiving regular reflection light emitted from the light projector 41a to the analysis region on the surface of the glass ribbon 22 by the light receiver 41b. , The analysis region (dotted line region in FIG. 3) is imaged.

  An LED light source can be preferably used as the light projector 41a, and a CCD area sensor can be preferably used as the light receiver 41b. The light source may be a fiber light source using a light source other than the LED, but an LED light source is preferable in consideration of a use environment (atmosphere of 100 ° C. or less). Further, in order to perform real-time control, it is preferable that the number of times of imaging by the light receiver 41b be 1 minute or less.

  The imaging unit 41 is provided in the vicinity of both sides 23 of the glass ribbon 22, and images the images of both ends 24 and the images of the plurality of recesses T as inspection images having coordinates. The position and interval of each recess T can be calculated from the image coordinates.

  Since there are various factors for varying the plate thickness deviation, in the specific top roll 50, the rotation speed V of the tip end portion 51 of the top roll 50, the angle θ formed by the tip end portion 51 in plan view with the transport direction, and the tip end in plan view. By controlling at least one of the position of the part 51 and the position of the tip part 51 in the vertical direction, it is possible to minimize fluctuations in the plate thickness deviation. In addition, controlling the conveyance speed L of the glass ribbon 22 on the layer roll 31 and the withdrawal amount of the glass ribbon 22 per day can also contribute to the suppression of fluctuations in the plate thickness deviation.

  The rotation speed V of the tip portion 51 of the top roll 50, the angle θ formed by the tip portion 51 in plan view with the transport direction, the position of the tip portion 51 in plan view, and the position of the tip portion 51 in the vertical direction are instructed by the controller 60. Thus, control can be performed by changing the rotation speed of the tip portion 51 that is interlocked with the driving portion 61, changing the rotating shaft 53, and changing the pressing force. Further, the conveyance speed L of the glass ribbon 22 and the withdrawal amount per day can be controlled by changing the rotation speed of the layer roll 31 which is interlocked with the drive unit 62 according to a command from the control unit 60.

  The distance D between the protrusions 52 of each top roll 50 (FIG. 2C) is set to the same value, but as shown in FIG. 4, at least a pair of top rolls 504 has a distance D between the protrusions 52 other than that. May be different from the plurality of pairs of top rolls 501, 502, 503.

  5A and 5B show another embodiment of the image pickup unit 41 of the analysis device 40. FIG. 5A is a conceptual diagram of the image pickup unit 41 of the transmission optical system, and FIG. 5B is obtained by the image pickup unit 41 of the transmission optical system. It is a schematic diagram of an image.

  As shown in FIG. 5A, in the imaging unit 41, the transmitted light that has passed through the glass ribbon 22 from the projector 45 provided below the glass ribbon 22 is detected by the light receiver 46 provided above the glass ribbon 22. Then, the inspection image is obtained. As a result, in the imaging unit 41 of the transmissive optical system, the dot-shaped recess T formed by the protrusion 52 of the top roll 50 biting into the surface of the glass ribbon 22 is imaged. In this case, by arranging the screen 47 between the glass ribbon 22 and the light projector 45, the recess T can be made clear. Therefore, the left end to the right end of the recess T in FIG. 5B is the recess T to be analyzed, and an inspection image of the recess T can be obtained as in the case of the imaging unit 41 of the reflective optical system shown in FIG. .

  The following apparatus may be attached to the float glass manufacturing apparatus 1 of the present embodiment.

  A pair of monitoring devices having a cooling monitoring camera, a reflecting mirror, and the like are arranged between adjacent top rolls 50 or on the downstream side of the most downstream top roll 50, and both side portions 23 of the glass ribbon 22 in the float bath 20 are arranged. May be monitored. In the embodiment of FIG. 1, a monitoring device 73 is provided between two top rolls 50 that are adjacent to each other in the transport direction of the glass ribbon 22, and a monitoring device 72 is provided on the downstream side of the most downstream top roll 50. Both sides 23 in position are monitored.

  A radiation thermometer may be arranged over the entire width direction in the float bath 20 and the temperature in the width direction of the glass ribbon 22 may be monitored over the entire width.

  Further, the temperature may be monitored by the radiation thermometer, and the temperature of the glass ribbon 22 may be controlled for each section by using the heaters arranged in the sections divided in the float bath 20. Thereby, the thickness of the glass ribbon 22 can be controlled uniformly.

  It should be noted that the present invention is not limited to the above-described embodiments, and modifications, improvements, etc. can be appropriately made. In addition, the material, shape, size, numerical value, form, number, arrangement location, etc. of each constituent element in the above-described embodiments are arbitrary and are not limited as long as the present invention can be achieved.

  The applications of the manufactured float glass include construction, vehicles, flat panel displays, cover glasses, and various other applications.

1 Float Glass Manufacturing Equipment 10 Melting Furnace 20 Float Bath 21 Molten Metal 22 Glass Ribbon 23 Both Sides 24 Both Ends 30 Slow Cooling Furnace 31 Layer Roll 40 Analyzing Device 41 Image Sensing Unit 42 Image Processing Identifying Unit 43 Display Unit 50 Top Roll 51 Tip Part 52 Projecting Part 53 Rotation axis D Distance between protrusions L Transport speed of glass ribbon T Recess V Rotation speed of tip θ Angle between tip and conveyance direction

Claims (9)

Float glass manufacturing apparatus provided with a float bath for forming a glass ribbon while flowing molten glass continuously supplied onto the molten metal on the molten metal, and an annealing furnace for gradually cooling the glass ribbon while conveying the glass ribbon with a layer roll. Which is applied to the analysis device for analyzing a plurality of recesses formed on both sides in the width direction of the glass ribbon,
The float bath comprises a plurality of pairs of top rolls provided at intervals along the flow direction of the glass ribbon,
The top roll has a plurality of protrusions on the outer periphery of the tip end portion that comes into contact with the glass ribbon, supports both side portions in the width direction of the glass ribbon, and forms the recesses at intervals along the flow direction. Formed,
The analysis device is
An image capturing unit that captures both side portions in the width direction of the glass ribbon,
After image processing of the inspection image captured by the image capturing unit, the position of the recess is detected, and based on the interval between the recesses in the flow direction, the top roll having the recess having the predetermined interval is formed. An image processing identification unit for identifying,
An analysis device including.   The image processing identification unit is a value calculated by dividing the rotation speed of the tip portion by multiplying the interval of the protrusions in the circumferential direction of the tip portion by the conveyance speed of the glass ribbon on the layer roll, Comparing the distance between the recesses in the flow direction, the top roll forming the recess having the distance closest to the value, the top roll is identified as a top roll having the rotation speed, The analysis device according to claim 1.   The analysis device according to claim 1, wherein the image processing identification unit detects the positions of both ends of the glass ribbon in the width direction. A float glass manufacturing apparatus comprising the analysis device according to claim 1.
Based on the identified change over time in the position of the recessed portion, the amount of the glass ribbon pulled out per day, the transport speed of the glass ribbon on the layer roll, the rotation speed of the tip portion, and the tip portion in plan view are A float glass manufacturing apparatus that controls one or more of an angle formed with a conveyance direction of a glass ribbon, a position of the tip portion in a plan view, and a position of the tip portion in a vertical direction.   The float glass manufacturing apparatus according to claim 4, wherein, in the plurality of pairs of the top rolls, the rotational speed of the leading end portion increases as it goes downstream in the flow direction.   The float glass manufacturing apparatus according to claim 4 or 5, wherein at least a pair of the top rolls has an interval between the protrusions in the circumferential direction of the tip end portion different from that of the other pairs of the top rolls.   Based on the change over time in the positions of both ends in the width direction of the glass ribbon, the withdrawal amount of the glass ribbon per day, the conveyance speed of the glass ribbon on the layer roll, the rotation speed of the tip portion, the tip in plan view The unit controls one or more of an angle formed by the section with the transport direction, a position of the tip section in a plan view, and a position of the tip section in a vertical direction. Float glass manufacturing equipment. Float glass manufacturing apparatus provided with a float bath for forming a glass ribbon while flowing molten glass continuously supplied onto the molten metal on the molten metal, and an annealing furnace for gradually cooling the glass ribbon while conveying the glass ribbon with a layer roll. Which is applied to the analysis method for analyzing a plurality of concave portions formed on both sides in the width direction of the glass ribbon,
The float bath comprises a plurality of pairs of top rolls provided at intervals along the flow direction of the glass ribbon,
The top roll has a plurality of protrusions on the outer periphery of the tip end portion that comes into contact with the glass ribbon, supports both side portions in the width direction of the glass ribbon, and forms the recesses at intervals along the flow direction. Formed,
The analysis method is
A step of imaging both side portions in the width direction of the glass ribbon,
A step of performing image processing on the captured inspection image, detecting the position of the concave portion, and identifying the top roll having the concave portion having the predetermined distance, based on the distance between the concave portions in the flow direction. ,
An analysis method comprising. A float glass manufacturing method using the analysis method according to claim 8,
Based on the identified change over time in the position of the recessed portion, the amount of the glass ribbon pulled out per day, the transport speed of the glass ribbon on the layer roll, the rotation speed of the tip portion, and the tip portion in plan view are A float glass manufacturing method, which controls one or more of an angle formed with a glass ribbon transport direction, a position of the tip portion in a plan view, and a position of the tip portion in a vertical direction.

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