WO2012132425A1 - Procédé de production de feuille de verre et dispositif de production de feuille de verre - Google Patents

Procédé de production de feuille de verre et dispositif de production de feuille de verre Download PDF

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Publication number
WO2012132425A1
WO2012132425A1 PCT/JP2012/002144 JP2012002144W WO2012132425A1 WO 2012132425 A1 WO2012132425 A1 WO 2012132425A1 JP 2012002144 W JP2012002144 W JP 2012002144W WO 2012132425 A1 WO2012132425 A1 WO 2012132425A1
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WIPO (PCT)
Prior art keywords
roller
glass
glass ribbon
temperature
speed
Prior art date
Application number
PCT/JP2012/002144
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English (en)
Japanese (ja)
Inventor
哲郎 君嶋
公彦 中嶋
真嗣 山崎
Original Assignee
ＡｖａｎＳｔｒａｔｅ株式会社
アヴァンストレート コリア インコーポレイテッド
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Application filed by ＡｖａｎＳｔｒａｔｅ株式会社, アヴァンストレート コリア インコーポレイテッド filed Critical ＡｖａｎＳｔｒａｔｅ株式会社
Priority to CN2012800006628A priority Critical patent/CN102933514B/zh
Priority to JP2012516255A priority patent/JP5288386B2/ja
Priority to KR1020127010848A priority patent/KR101300909B1/ko
Publication of WO2012132425A1 publication Critical patent/WO2012132425A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B18/00—Shaping glass in contact with the surface of a liquid
    • C03B18/02—Forming sheets
    • C03B18/04—Changing or regulating the dimensions of the molten glass ribbon
    • C03B18/06—Changing or regulating the dimensions of the molten glass ribbon using mechanical means, e.g. restrictor bars, edge rollers
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B17/00—Forming molten glass by flowing-out, pushing-out, extruding or drawing downwardly or laterally from forming slits or by overflowing over lips
    • C03B17/06—Forming glass sheets
    • C03B17/064—Forming glass sheets by the overflow downdraw fusion process; Isopipes therefor
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B17/00—Forming molten glass by flowing-out, pushing-out, extruding or drawing downwardly or laterally from forming slits or by overflowing over lips
    • C03B17/06—Forming glass sheets
    • C03B17/068—Means for providing the drawing force, e.g. traction or draw rollers
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B18/00—Shaping glass in contact with the surface of a liquid
    • C03B18/02—Forming sheets
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P40/00—Technologies relating to the processing of minerals
    • Y02P40/50—Glass production, e.g. reusing waste heat during processing or shaping
    • Y02P40/57—Improving the yield, e-g- reduction of reject rates

Definitions

  • the present invention relates to a glass plate manufacturing method and a glass plate manufacturing apparatus.
  • the glass ribbon is drawn down while being held by the pair of transport rollers, and thus is stretched to a desired thickness, and further, no distortion occurs inside.
  • cooling is performed so that the glass ribbon does not warp.
  • the glass ribbon is cut into a predetermined size and stacked on each other with an interleaf or the like interposed therebetween, or further conveyed and processed in the next process (for example, shape processing, chemical strengthening treatment by ion exchange).
  • the rotational drive is controlled so that the same load is applied to each of the transport rollers of the transport roller pair, and slip caused by the difference in outer diameter between the transport rollers It is known that one of the conveying rollers is prevented from idling by preventing this (Patent Document 1). According to this, the glass surface and the conveyance roller can be prevented from being damaged.
  • the relative speed between the peripheral speed of the transport roller provided at each position in the glass ribbon transport direction and the transport speed of the glass ribbon Is preferably 0, but the coefficient of thermal expansion of the glass and the coefficient of thermal expansion of the conveying roller are different, and the temperature dependency thereof is also different. There is a difference in speed. Such a difference in relative speed is also caused by, for example, changes in the atmospheric temperature in the slow cooling furnace and the temperature of the glass ribbon due to changes in the conveyance speed and thickness of the glass ribbon, fluctuations in the airflow generated in the slow cooling furnace, and the like.
  • Patent Document 1 even if control is performed so that the loads on the conveyance rollers of the conveyance roller pair are equal, the actual conveyance speed of the glass ribbon generated between the plurality of conveyance roller pairs. The difference in the relative speed between the transport speed and the peripheral speed of the transport roller cannot be eliminated, and the occurrence of scratches on the glass surface due to slip cannot be prevented.
  • the relative speed is not constant between the required transport speed, which is the target speed of transport of the glass ribbon, and the peripheral speed of the transport roller, among the plurality of transport roller pairs, that is, if a difference in relative speed occurs, the glass ribbon If the actual transport speed is slower than the required transport speed, the glass ribbon will be deformed too much above the pair of transport rollers. Conversely, if the actual transport speed is faster than the required transport speed, the glass ribbon will be pulled downward. There is a risk of cracking due to fine scratches generated on the surface.
  • the glass plate manufacturing apparatus changes over time by continuously forming and slowly cooling the glass ribbon for a long period of time. For this reason, even if the manufacturing conditions in molding and slow cooling are initially set so that a high-quality (small internal strain and warpage) glass plate can be manufactured, it is not always possible to maintain a high-quality glass plate by continuous operation over a long period of time.
  • the diameter of the conveying roller in contact with the glass ribbon changes and greatly affects the quality of the glass plate.
  • the present invention has as a first object to maintain the production of a high-quality glass plate even if the production equipment changes over time by continuous production of the glass plate for a long period of time.
  • a method for producing a glass plate is provided.
  • the second purpose is to maintain the peripheral speed distribution of the transport roller changed by the change in the diameter of the transport roller in the set peripheral speed distribution, and between the transport roller pair, the peripheral speed of the transport roller and the transport speed of the glass ribbon. It is possible to prevent a difference in the relative speed of the glass plate, and thereby to provide a glass plate manufacturing method and a glass plate manufacturing apparatus capable of manufacturing a glass plate excellent in surface quality.
  • One embodiment of the present invention is a method for manufacturing a glass plate.
  • the manufacturing method is Melting process for melting glass raw material to make molten glass; Molding a molten glass using a downdraw method to form a glass ribbon; A slow cooling step in which the glass ribbon is slowly cooled by being pulled downward while being sandwiched by a plurality of roller pairs provided along the conveying direction of the glass ribbon.
  • the forming step includes a step of cooling both ends of the glass ribbon while pulling down the glass ribbon while sandwiching the glass ribbon with a pair of rollers.
  • Each roller of the first roller pair which is at least one of the pair of rollers used in any one of the forming step and the slow cooling step, is determined to compensate for a change in the diameter of the roller. It is driven to rotate based on the rotational speed of.
  • Another embodiment of the present invention is a method for producing a glass plate.
  • the manufacturing method is Melting process for melting glass raw material to make molten glass; Molding a molten glass using a downdraw method to form a glass ribbon; A slow cooling step in which the glass ribbon is slowly cooled by being pulled downward while being sandwiched by a plurality of roller pairs provided along the conveying direction of the glass ribbon.
  • the slow cooling step includes Each roller of the first roller pair, which is at least one of the roller pairs, is driven to rotate based on the rotational speed of the roller determined so as to compensate for the change in the roller diameter.
  • the slow cooling step A detection step of detecting a change in the diameter of each roller of the first roller pair by a detection unit provided along the conveyance direction of the glass ribbon; And a speed control step of determining a rotational speed of each roller based on the detected diameter change of each roller of the first roller pair and rotationally driving each roller of the first roller pair. preferable.
  • Each roller of the first roller pair is provided in a temperature region in which the temperature of at least the center of the glass ribbon in the slow cooling step is a glass transition point or more and a softening point or less, In the slow cooling step, the rotational speed of each roller of the first roller pair is determined so as to compensate for a change in the diameter of each roller of the first roller pair, and each roller of the first roller pair is driven to rotate. It is preferable.
  • the temperature of the glass ribbon is controlled so as to decrease from the center to the end.
  • the glass ribbon is configured such that there is no temperature gradient between the end portion and the center portion in the width direction of the glass ribbon in the temperature region near the glass strain point of the glass ribbon. To control the temperature distribution.
  • the glass ribbon In the slow cooling step, In the region where the temperature of the central portion of the glass ribbon is less than the vicinity of the strain point, the glass ribbon is lowered from the end in the width direction toward the central portion so that tensile stress in the transport direction acts on the central portion of the glass ribbon. Thus, it is preferable to control the temperature distribution of the glass ribbon.
  • the slow cooling step includes A first cooling step of cooling at a first average cooling rate until the temperature of the central portion of the glass ribbon reaches a slow cooling point; A second cooling step of cooling at a second average cooling rate until the temperature of the central portion reaches a strain point of ⁇ 50 ° C. from the annealing point; It is preferable to include a third cooling step of cooling at a third average cooling rate until the temperature of the central portion becomes from the strain point of ⁇ 50 ° C. to the strain point of ⁇ 200 ° C.
  • the first average cooling rate is 5.0 ° C./second or more
  • the first average cooling rate is faster than the third average cooling rate
  • the third average cooling rate is: Faster than the second average cooling rate.
  • each roller of the first roller pair is determined so as to compensate for the deviation of the peripheral speed caused by the change in the diameter of each roller of the first roller due to the thermal expansion of each roller of the first roller pair.
  • each roller of the first roller pair is driven to rotate.
  • each roller of the first roller pair is compensated for the deviation of the peripheral speed caused by the diameter change of each roller of the first roller pair due to the wear of each roller of the first roller pair. It is also preferable that each of the first roller pair is rotationally driven.
  • a roller pair having a roller driven to rotate based on a rotation speed of the roller determined so as to compensate for a change in the diameter of the roller is a second roller pair in addition to the first roller pair.
  • the manufacturing method includes a detection step of detecting a change in the diameter of each of the first roller pair and the second roller pair by a plurality of detection units provided along the conveyance direction of the glass ribbon. .
  • the diameter of each roller is set so that the relative speed between the peripheral speed of the roller and the conveying speed of the glass ribbon is constant between each roller of the first roller pair and each roller of the second roller pair.
  • the rotational speed of each roller that compensates for the change is determined.
  • the temperature of the glass ribbon is detected by a glass state detection unit that detects the state of the glass ribbon provided along the conveyance direction of the glass ribbon, Using the glass thermal expansion coefficient at the detected temperature of the glass ribbon, a change in the transport speed of the glass ribbon due to the thermal expansion of the glass ribbon is detected, and the transport speed of the glass ribbon and the peripheral speed of the roller It is also preferable to determine the rotational speed of each roller of the first roller pair so as to compensate for the deviation.
  • the thickness of the glass plate obtained by gradually cooling the glass ribbon is, for example, 0.5 mm or less.
  • the device is A molding apparatus for molding a glass ribbon from molten glass using a downdraw method; And a slow cooling device that cools the glass ribbon while pulling it downward while sandwiching it with a plurality of pairs of transport rollers.
  • the slow cooling device includes the plurality of conveyance roller pairs, a detection control unit, and a drive unit.
  • the plurality of transport roller pairs are provided along the transport direction of the glass ribbon, and transport the glass ribbon by drawing the glass ribbon downward.
  • the said detection control part is provided along the conveyance direction of the said glass ribbon, and is provided with the some conveyance roller state detection part which detects the diameter change of the conveyance roller of the said conveyance roller pair.
  • the drive unit maintains a peripheral speed distribution between the plurality of transport roller pairs when a relative speed between the peripheral speed of the transport roller and the transport speed of the glass ribbon is constant between the plurality of transport roller pairs. Then, the transport roller is driven to rotate based on the rotation speed of each transport roller determined based on the detected diameter change of the transport roller.
  • the transport roller state detection unit detects a change in the diameter of the transport roller based on the temperature of the transport roller
  • the drive unit detects the temperature of the transport roller so as to compensate for a deviation from the peripheral speed distribution of the peripheral speed of the transport roller caused by a change in the diameter of the roller due to thermal expansion of the transport roller. It is preferable that the transport roller is rotationally driven based on the rotational speed of each transport roller determined using the roller thermal expansion coefficient.
  • the detection unit further includes a plurality of glass state detection units provided along a conveyance direction of the glass ribbon to detect the state of the glass ribbon, and the driving unit is set based on the state of the glass ribbon. It is preferable that the transport roller is driven to rotate based on the peripheral speed distribution.
  • the glass state detection unit detects the temperature of the glass ribbon
  • the driving unit uses the glass thermal expansion coefficient at the detected temperature of the glass ribbon, and the peripheral speed distribution set according to the change in the conveyance speed of the glass ribbon due to the thermal expansion of the glass ribbon. It is preferable that the transport roller is rotationally driven based on the base.
  • the transport roller state detection unit detects a change in the diameter of the transport roller based on an amount of wear of the transport roller,
  • the drive unit is determined to compensate for a deviation from the peripheral speed distribution of the peripheral speed of the transport roller, which is caused by a change in the diameter of the transport roller due to the detected wear of the transport roller. It is preferable that the transport roller is rotationally driven based on the rotational speed of the transport roller.
  • the thickness of the glass plate obtained by gradually cooling the glass ribbon is, for example, 0.5 mm or less.
  • the production of a high-quality glass plate can be maintained even if the production equipment such as a conveyance roller in contact with the glass ribbon changes with time by continuous production of the glass plate for a long period of time.
  • the glass plate manufacturing method and the glass plate manufacturing apparatus described above maintain a peripheral speed distribution in which the peripheral speed of the transport roller, which has changed due to a change in the diameter of the transport roller, is maintained, and a transport roller between a plurality of transport roller pairs. It is possible to prevent a difference from occurring in the relative speed between the peripheral speed and the glass ribbon transport speed. Thereby, the glass plate excellent in surface quality can be manufactured.
  • FIG. 4 is a cross-sectional view taken along line IV in FIG. 3. It is a block diagram explaining the structure of the control system which controls the rotational drive of a conveyance roller pair. It is a block diagram explaining the structure of the control system which controls the rotational drive of the conveyance roller pair of the glass plate manufacturing apparatus of 2nd Embodiment of this invention.
  • the manufacturing method and glass plate manufacturing apparatus of the glass plate of this invention are demonstrated in detail.
  • at least of the roller pair (cooling roller pair, conveying roller pair) used in the forming step and the slow cooling step which are one step of the glass plate manufacturing method.
  • Each roller of any one roller pair (first roller pair) is rotationally driven based on the rotational speed of the roller determined so as to compensate for the change in the diameter of the roller.
  • each roller of at least one of the plurality of transport roller pairs (first roller pair) is based on the rotational speed of the roller determined so as to compensate for the change in the roller diameter. , Is driven to rotate.
  • the rotational speed of such a roller is determined so as to compensate for the diameter change by detecting the diameter change of each roller of the first roller pair by measurement. That is, the rotational speed of the roller is feedback controlled according to the detection result of the roller diameter change.
  • the rotational speed of the rollers is determined based on information on the number of days used for each roller of the first roller pair. That is, the rotation speed of the rollers is sequentially determined based on information on the usage period of each roller. “Information on the number of days of use” is used for conversion of the change of the roller diameter based on the wear of the first roller pair, and the rotation speed of the roller is determined based on the conversion value of the change of the roller diameter.
  • first roller pair There may be a single first roller pair or a plurality of first roller pairs for determining the rotational speed of such rollers.
  • “Compensating for changes in roller diameter” means that even if the diameter of each roller of the first roller pair changes, the appropriate peripheral speed of the roller before the diameter change is maintained in consideration of the change in diameter. means.
  • the central region of the glass ribbon refers to a range within 85% of the width from the center in the width direction of the glass ribbon in the width in the width direction of the glass ribbon.
  • the center portion of the glass ribbon refers to the center in the width direction of the glass ribbon. That the temperature in the central region of the glass ribbon is substantially uniform means that the temperature is within an allowable range of ⁇ 20 ° C.
  • the edge part of a glass ribbon means the range within 200 mm from the edge of the width direction of a glass ribbon.
  • FIG. 1 is a figure explaining an example of the flow of the manufacturing method of the glass plate of this embodiment.
  • the glass plate manufacturing method includes a melting step (step S10), a clarification step (step S20), a stirring step (step S30), a forming step (step S40), a slow cooling step (step S50), It mainly includes a process (step S60) and a shape processing process (step S70).
  • step S10 in a melting furnace (not shown), the glass raw material is heated to a high temperature by indirect heating from above and direct heating by passing an electric current through the glass to produce molten glass.
  • the melting of the glass may be performed by other methods.
  • a clarification process is performed (step S20).
  • the defoaming of bubbles in the molten glass is promoted by increasing the temperature of the molten glass in a state where the molten glass is stored in a liquid tank (not shown), for example, compared with the heating in the melting step. . Thereby, the bubble content rate in the glass plate finally obtained can be reduced, and a yield can be improved.
  • the clarification step may be performed by other methods.
  • bubbles in the molten glass may be removed using a clarifier.
  • the fining agent is not particularly limited, and for example, metal oxides such as tin oxide and iron oxide are used.
  • the clarification step in this case is performed by a redox reaction of a metal oxide whose valence fluctuates in the molten glass.
  • the metal oxide releases oxygen by a reduction reaction, and this oxygen becomes a gas, and bubbles in the molten glass grow and float on the liquid surface. Thereby, bubbles in the molten glass are defoamed.
  • the bubble of oxygen gas takes in the gas in the other bubble in a molten glass, grows, and floats on the liquid level of a molten glass. Thereby, bubbles in the molten glass are defoamed. Further, when the temperature of the molten glass is lowered, the metal oxide absorbs oxygen remaining in the molten glass due to the oxidation reaction, and reduces bubbles in the molten glass.
  • a stirring process is performed (step S30).
  • the molten glass is mechanically stirred by a stirring device in order to maintain the chemical and thermal uniformity of the glass. Thereby, nonuniformity of the glass such as striae can be suppressed.
  • a molding process is performed (step S40).
  • a downdraw method is used.
  • the down draw method including overflow down draw, slot down draw, and the like is a known method using, for example, Japanese Patent No. 3586142 or the apparatus shown in FIGS.
  • the molding process in the downdraw method will be described later.
  • a sheet-like glass ribbon having a predetermined thickness and width is formed.
  • an overflow downdraw is most preferable among the downdraw methods, but a slot downdraw may be used.
  • the forming step includes a step of cooling both ends of the glass ribbon while drawing the glass ribbon formed by the forming with a pair of rollers and pulling it downward in the conveying direction (downstream direction).
  • a slow cooling process is performed (step S50).
  • the glass ribbon formed into a sheet shape is cooled below the annealing point in the slow cooling furnace shown in FIGS. 3 and 4 by controlling the cooling rate so that distortion does not occur or is reduced.
  • a conveyance speed that is set in advance while the adjacent region adjacent to the width direction end of the glass ribbon in the width direction is sandwiched between a plurality of pairs of conveyance rollers provided in the conveyance direction of the glass ribbon. It is gradually cooled while being pulled down at.
  • FIG. 2 is a diagram illustrating an example of the flow of the slow cooling process.
  • the slow cooling process includes a detection process (step S51), a speed determination process (step S52), and a speed control process (step S53).
  • the manufacturing method of the glass plate of this embodiment includes a detection process (step S51), a detection process is not performed like the modification mentioned later, and a slow cooling process is a speed determination process (step S52), And a speed control step (step S53).
  • the diameter change of each conveyance roller of the plurality of conveyance roller pairs is performed by the plurality of detection units provided corresponding to the plurality of conveyance roller pairs described above along the conveyance direction of the glass ribbon. Is detected.
  • the diameter change of the transport roller for example, the diameter change amount of the transport roller calculated based on the temperature of the transport roller or the wear amount of the transport roller can be mentioned.
  • the detection unit in this case includes, for example, a temperature sensor or a distance measurement sensor described later, and a computer connected to these sensors. As the diameter, the diameter or radius of the transport roller is increased.
  • the relative speed between the peripheral speed of the transport roller and the transport speed of the glass ribbon is constant between the plurality of transport roller pairs, that is, when there is no difference in the relative speed.
  • the rotational speed of each transport roller is determined so as to maintain the set peripheral speed distribution based on the detected change in the diameter of the transport roller.
  • the peripheral speed distribution for example, a peripheral speed ratio between a plurality of pairs of transport rollers and a specific peripheral speed of each transport roller are used.
  • a difference in the relative speed means that the relative speed of a certain pair among the plurality of transport roller pairs is 0.
  • the relative speed of another pair has a distribution such that the relative speed is not zero.
  • the change in the diameter of the conveyance roller is, for example, a thermal expansion amount (diameter change amount) of the conveyance roller calculated based on the temperature, specifically, the detection unit 37 and the speed determination unit 38 described later perform the change.
  • the roller thermal expansion coefficient at the detected transport roller temperature is used to compensate for the deviation of the peripheral speed of the transport roller from the peripheral speed distribution caused by the change in the roller diameter caused by the thermal expansion of the transport roller.
  • the rotational speed of the transport roller is determined so that the peripheral speed of each transport roller is maintained in the set peripheral speed distribution.
  • the thermal expansion coefficient of the transport roller is stored in advance in the speed determination unit 38.
  • the circumferential speed of a conveyance roller is determined by adjusting so that the formed glass ribbon may become the plate
  • the change in the diameter of the transport roller is the amount of change in the radius of the transport roller calculated based on the amount of wear
  • detection is performed as in the second embodiment described later.
  • the peripheral speed of each transport roller was set so as to compensate for the deviation from the peripheral speed distribution of the peripheral speed of the transport roller caused by the change in the radius of the transport roller due to wear of the transport rollers.
  • the rotation speed of the transport roller is determined so that the peripheral speed distribution is maintained.
  • the speed determination unit 38 may determine the rotation speed of each transport roller based on the content input by the operator.
  • the operator may calculate the rotation speed of each conveyance roller based on the detected change in the diameter of the conveyance roller so as to maintain the set peripheral speed distribution.
  • the change in the diameter of the conveyance roller is the above-described amount of thermal expansion
  • the operator can change the diameter of the conveyance roller caused by the change in the roller diameter caused by the thermal expansion of the conveyance roller based on the detected temperature of the conveyance roller.
  • the rotational speed of the transport roller may be calculated so as to compensate for the deviation of the peripheral speed from the peripheral speed distribution, that is, so that the peripheral speed of each transport roller is maintained at the set peripheral speed distribution.
  • the rotation speed of each transport roller calculated and input is determined by the speed determination unit 38, and the rotation of the transport roller is controlled in the speed control step (step S53).
  • step S53 the rotation of the transport roller is controlled based on the rotation speed determined in the speed determination process.
  • a plate-making process is performed (step S60). Specifically, the glass ribbon produced
  • a shape processing step is performed (step S70).
  • the glass end face is ground and polished in addition to cutting into a predetermined glass plate size and shape.
  • a physical means using a cutter or a laser may be used, or a chemical means such as etching may be used.
  • the end portion in the width direction of the glass ribbon is the end. It is preferable to control the temperature of the glass ribbon so that it is lower than the temperature of the central region sandwiched between the parts and the temperature of the central region is substantially uniform. At that time, the temperature in the width direction of the glass ribbon is the center of the glass ribbon so that the tensile stress in the transport direction acts on the center portion of the glass ribbon in the region where the temperature of the center portion of the glass ribbon is less than the softening point and near the strain point.
  • the temperature of the glass ribbon so as to decrease from the portion toward the end in terms of suppressing warpage of the glass plate. Furthermore, in the temperature region where the temperature of the glass ribbon is in the vicinity of the strain point, it is possible to control the temperature distribution of the glass ribbon so that there is no temperature gradient between the end portion in the width direction of the glass ribbon and the center portion. This is preferable in terms of suppressing internal distortion.
  • the glass ribbon is lowered from the end in the width direction toward the central portion so that tensile stress in the transport direction acts on the central portion of the glass ribbon.
  • the slow cooling step includes a first cooling step of cooling at the first average cooling rate until the temperature of the central portion of the glass ribbon reaches a slow cooling point, and the temperature of the central portion of the glass ribbon is gradually cooled. From the point until the strain point reaches ⁇ 50 ° C., the second cooling step of cooling at the second average cooling rate and the temperature of the central portion of the glass ribbon reaches from the strain point ⁇ 50 ° C. to the strain point ⁇ 200 ° C. And a third cooling step of cooling at a third average cooling rate.
  • the first average cooling rate is 5.0 ° C./second or more
  • the first average cooling rate is faster than the third average cooling rate
  • the third average cooling rate is the second average cooling rate. Faster than the cooling rate.
  • the average cooling rate is, in descending order, the first average cooling rate, the third average cooling rate, and the second average cooling rate.
  • the cooling rate in the conveyance direction of the glass ribbon affects the heat shrinkage of the glass plate to be manufactured.
  • the cooling rate in the slow cooling step as described above, it is possible to obtain a glass plate having a suitable heat shrinkage rate while improving the production amount of the glass plate.
  • the glass plate manufacturing method has a cleaning process and an inspection process in addition to this, but the description of these processes is omitted.
  • the clarification step and the stirring step can be omitted.
  • FIG.3 and FIG.4 is a schematic block diagram of the glass plate manufacturing apparatus 1 which is 1st Embodiment of this invention.
  • the glass plate manufacturing apparatus 1 and the glass plate manufacturing method using the glass plate manufacturing apparatus 1 according to this embodiment include a glass substrate of a flat panel display such as a liquid crystal display device or an organic EL display device, and a display surface cover of a portable terminal. It is suitably applied to the production of glass. This is because liquid crystal display devices, organic EL display devices, and the like have recently been required to have high precision and high image quality, and a glass substrate used therefor is required to have high surface quality.
  • the glass plate manufacturing apparatus 1 manufactures the glass plate C from the molten glass A using the downdraw method.
  • the glass plate manufacturing apparatus 1 includes a furnace chamber 11, a first slow cooling furnace 12, a second slow cooling furnace 13, and a sampling chamber (not shown) that are partitioned by heat insulating plates 21, 22, and 23 arranged in three locations in the vertical direction.
  • the heat insulating plates 21 to 23 are plate members made of a heat insulating material such as ceramic fiber.
  • the heat insulating plates 21 to 23 are respectively formed with transport holes 16 so that a glass ribbon B, which will be described later, passes downward.
  • the heat insulating plates 21 to 23 are not shown in FIG. 3 except for two places in the horizontal direction in contact with the furnace wall 15 which will be described later for easy understanding. On the back side, the two horizontal portions are connected together. 3 and 4 show an example in which partitioning is performed at three locations by a heat insulating plate, but the number and installation positions of the heat insulating plates are not particularly limited, and one or more heat insulating plates may be provided. That's fine.
  • the slow cooling apparatus 3 has two or more heat insulation plates. It is preferably provided and partitioned into a plurality of spaces. In other words, it is sufficient that one or more annealing furnaces are provided, but three or more are more preferably provided.
  • the glass plate manufacturing apparatus 1 includes a forming device 2, a slow cooling device 3, and a plate-taking device 4.
  • the forming apparatus 2 is an apparatus for forming the glass ribbon B from the molten glass A using a downdraw method.
  • the forming apparatus 2 has a furnace chamber 11 surrounded by a furnace wall 15 assembled with refractory bricks, block-shaped electroformed column refractories, or the like.
  • a molded body 10 and a roller pair (cooling roller pair) 17 are provided in the furnace chamber 11.
  • the molded body 10 includes a groove 10a opened upward (see FIG. 4), and the molten glass A flows in the groove 10a.
  • the molded body 10 is made of brick, for example.
  • One pair of rollers 17 is provided at positions corresponding to both ends in the width direction of the molten glass A fused at the lower end of the molded body 10, and the glass ribbon is held while holding the molten glass A and pulling it downward.
  • a pair of cooling rollers for cooling both ends of B is the left-right direction in the paper surface in FIG. 3 and the direction perpendicular to the paper surface in FIG. 3 and 4 is the transport direction of the glass ribbon B. 3 and 4, the molded body 10 and the roller pair 17 are installed without partitioning, but in order to facilitate adjustment of the slow cooling conditions, a partition plate is provided by providing a heat insulating plate therebetween. May be. Two or more pairs of rollers 17 may be installed.
  • the slow cooling device 3 cools the glass ribbon B while pulling it downward while holding the glass ribbon B between the plurality of conveying roller pairs 18 and 19.
  • the slow cooling device 3 has a first slow cooling furnace 12 and a second slow cooling furnace 13 provided adjacent to the lower part of the furnace chamber 11.
  • the first slow cooling furnace 12 and the second slow cooling furnace 13 are surrounded by the furnace wall 15 that also constitutes the furnace chamber 11.
  • the slow cooling device 3 is provided with heating means that are arranged in the first slow cooling furnace 12 and the second slow cooling furnace 13 along the conveying direction of the glass ribbon B and are automatically controlled by a computer to be described later.
  • the heating means is not particularly limited, and for example, an electric heater is used.
  • the slow cooling device 3 includes a detection control unit 30 and a drive unit 32 (see FIG. 5).
  • the detection control unit 30 and a drive unit 32 (see FIG. 5).
  • the conveyance roller pairs 18 and 19 convey the glass ribbon B by drawing the glass ribbon B downward.
  • Each conveyance roller pair 18 is on the same side with respect to the glass ribbon B as the four conveyance rollers 18a arranged on both sides of the glass ribbon B so as to sandwich a neighboring region adjacent to both ends in the width direction of the glass ribbon B. It has two drive shafts 18b arranged on both sides of the glass ribbon B for connecting the two transport rollers 18a.
  • Each conveyance roller pair 19 is on the same side with respect to the glass ribbon B as the four conveyance rollers 19a disposed on both sides of the glass ribbon B so as to sandwich a neighboring region adjacent to both ends in the width direction of the glass ribbon B.
  • both ends of the drive shafts 18b and 19b are not shown.
  • the transport rollers 18a and 19a are not limited to those described above.
  • the conveying rollers 18a and 19a on the same surface side with respect to the glass ribbon B are not connected to each other by the driving shaft, and at the both ends in the width direction of the glass ribbon B, like the rollers of the roller pair 17. It may be arranged independently.
  • the glass ribbon B has a temperature profile of the glass ribbon B with a single distribution in the width direction, and then gradually decreases as the distribution of the single peak progresses downstream in the conveyance direction. It is preferable to control a heater or the like disposed around the. At that time, in a temperature region in the vicinity of the strain point of the glass ribbon B, a heater or the like (not shown) can be controlled so that the distribution of peaks is a straight linear distribution, that is, the temperature distribution in the width direction is constant. preferable. In other words, in the temperature range from the temperature obtained by adding 150 ° C.
  • the cooling rate at the center in the width direction of the glass ribbon is faster than the cooling rate at both ends in the width direction.
  • the temperature profile be constant so that the temperature of the central portion in the width direction of the glass ribbon B is the same in the temperature region near the strain point from a state where the temperature is higher than both ends.
  • the glass ribbon B is gradually cooled at a temperature at which the temperature of the glass ribbon B becomes from the annealing point (strain point ⁇ 50 ° C.) as compared with other temperature ranges.
  • the thermal contraction rate of the glass ribbon B can be reduced.
  • the temperature profile of the glass ribbon B becomes a valley along the width direction, and the depth of the valley is conveyed. It is preferable to control a heater or the like (not shown) so as to increase as it goes downstream in the direction, that is, so that the temperature at the center portion becomes gradually lower than both end portions.
  • the detection control unit 30 includes a computer (not shown) that functions as a conveyance roller state detection unit (hereinafter also simply referred to as a detection unit) 37 and a speed determination unit 38.
  • FIG. 5 is a block diagram illustrating the configuration of a control system that controls the rotational drive of the transport roller pairs 18 and 19.
  • the detection unit 37 includes a temperature sensor (glass state detection unit) 34 disposed in correspondence with the pair of conveyance rollers 18 and 19.
  • the speed determining unit 38 is connected to the conveying roller pair 18 and 19 via the driving unit 32. Details of the detection control unit 30 will be described later.
  • the driving unit 32 rotationally drives the transport rollers 18a and 19a based on the rotational speeds of the transport rollers 18a and 19a determined by the speed determination unit 38.
  • the drive unit 32 has a motor (not shown) provided corresponding to each of the conveyance roller pairs 18 and 19.
  • the motor may not be provided corresponding to each conveyance roller pair 18, 19, and the number thereof may be smaller than the number of each conveyance roller pair 18, 19, for example.
  • the driving force from the motor is transmitted to the transport rollers 18a and 19a via, for example, a universal joint.
  • the temperature sensor 34 detects the temperature of the transport rollers 18a and 19a.
  • a contact type or a non-contact type is used as the temperature sensor 34.
  • detecting the temperatures of the transport rollers 18a and 19a includes calculating the temperatures of the transport rollers 18a and 19a.
  • Each temperature sensor 34 specifically detects the ambient temperature at the arrangement position in the first slow cooling furnace 12 and the second slow cooling furnace 13. And the temperature of conveyance roller 18a, 19a is calculated with reference to the temperature difference data memorize
  • the speed determination unit 38 has a storage unit 36.
  • the storage unit 36 stores temperature difference data.
  • the temperature difference data includes data on the difference between the atmospheric temperature of the slow cooling furnaces 12 and 13 and the temperature (surface temperature) of the transport rollers 18a and 19a at each atmospheric temperature, which is measured in advance when the slow cooling furnaces 12 and 13 are installed.
  • the temperature difference data is stored differently depending on the structure of the slow cooling furnaces 12 and 13.
  • the storage unit 36 further stores thermal expansion coefficients (hereinafter also referred to as roller thermal expansion coefficients) of the transport rollers 18a and 19a.
  • the roller thermal expansion coefficient is determined from the material of the transport rollers 18a and 19a.
  • the storage unit 36 also includes a rotational speed of each of the transport rollers 18a and 19a determined by the speed determination unit 38, a reference peripheral speed distribution set between the plurality of transport roller pairs 18 and 19, and each transport roller 18a. , 19a are further stored.
  • the reference value of the diameter of each of the transport rollers 18a and 19a is a diameter at the time of a new article at normal temperature (for example, 25 degrees).
  • the storage unit 36 also has conditions for achieving a reference peripheral velocity distribution (conveying roller temperature, glass ribbon temperature, glass ribbon thermal expansion coefficient, glass ribbon thickness, width, glass ribbon flow rate, etc. ) Is memorized.
  • the speed determination unit 38 is provided between the plurality of conveyance roller pairs 18 and 19 when the relative speed between the circumferential speed of the conveyance rollers 18a and 19a and the conveyance speed of the glass ribbon B is constant between the plurality of conveyance roller pairs 18 and 19. Set the peripheral speed ratio (peripheral speed distribution). Next, the speed determination unit 38 is configured to maintain the peripheral speed ratio between the plurality of conveyance roller pairs 18 and 19 based on the change in the diameter of the conveyance rollers 18a and 19a calculated by the detection unit 37. The rotational speed of 19a is determined.
  • the peripheral speed ratio between the plurality of transport roller pairs 18 and 19 is set to 1.0, for example, so that all the transport rollers 18a and 19a have the same peripheral speed.
  • the peripheral speed ratio set as a reference in this way is the peripheral speed ratio when the conventional glass ribbon B is gradually cooled without causing problems of scratches or shape deformation.
  • the reference peripheral speed distribution is stored and held in the speed determination unit 38 together with conditions such as the temperature, thermal expansion coefficient, thickness, width, and glass flow rate of the glass ribbon B. As will be described later, this peripheral speed ratio is set by correcting the reference peripheral speed distribution when conditions of slow cooling such as the temperature of the glass ribbon B change.
  • the relative speed between the conveyance speed of the glass ribbon B and the peripheral speed of the conveyance rollers 18a and 19a between the plurality of conveyance roller pairs 18 and 19 is more sure to slip between the glass ribbon B and the conveyance rollers 18a and 19a. From the viewpoint of preventing this, it is preferably 0.
  • the speed determination unit 38 corrects and sets the reference peripheral speed ratio according to the temperature, the thermal expansion coefficient, the thickness, the glass flow rate, and the like of the glass ribbon B. Specifically, a reference temperature in each pair of conveying rollers is set as a condition at that time in the peripheral speed ratio set as the reference peripheral speed distribution. Therefore, when the current temperature of the glass ribbon B changes with respect to this reference temperature, for example, when the temperature T 1 changes to T 2 , the difference in thermal expansion coefficient between the temperature difference between T 2 and T 1 is calculated. The speed determining unit 38 corrects the peripheral speed ratio set as the reference peripheral speed distribution. This is because the conveyance speed of the glass ribbon B changes depending on the coefficient of thermal expansion determined by the temperature of the glass ribbon B and the coefficient of thermal expansion.
  • the peripheral speed ratio may be more generally corrected using the difference in the thermal expansion coefficient in consideration of the thermal expansion coefficient and the temperature of the glass ribbon B.
  • Such a peripheral speed ratio is corrected and set by changes in conditions such as the thickness, width, and glass flow rate of the glass ribbon B in addition to the temperature dependency of the glass ribbon B and the thermal expansion coefficient. Therefore, the conditions of the reference peripheral speed ratio such as the temperature of the glass ribbon B, the temperature-dependent characteristics of the thermal expansion coefficient, the thickness, the width, and the glass flow rate are stored and held in advance in the speed determination unit 38.
  • the glass thermal expansion coefficient is determined from the composition of the molten glass.
  • the peripheral speeds of the respective transport roller pairs on the downstream side are calculated on the basis of the current peripheral speed of the transport roller pair on the most upstream side.
  • the peripheral speed ratio in accordance with the change in the state including the temperature of the glass ribbon B, it is possible to determine more appropriate rotation speeds of the transport rollers 18a and 19a.
  • the speed determination unit 38 determines the rotation speed of each of the transport rollers 18a and 19a according to the following formula based on the calculated peripheral speed of each of the transport rollers 18a and 19a.
  • Rotational speed peripheral speed / (diameter of thermally expanded conveying roller ⁇ ⁇ )
  • the detection unit 37 has the roller thermal expansion coefficient at the temperature of the conveyance rollers 18a and 19a and the conveyance roller 18a and 19a with respect to the conveyance rollers 18a and 19a whose temperature detected by the temperature sensor 34 has changed.
  • the speed determination unit 38 calculates a new rotation speed from the amount of change in the diameter of the conveyance roller 18a calculated by the detection unit 37 according to the following formula, assuming that the amount of change in the peripheral speed is 1, and the conveyance rollers 18a and 19a. Change the rotation speed.
  • New rotation speed (peripheral speed + change amount of peripheral speed) / ((change diameter of transport roller + change amount of transport roller diameter) ⁇ ⁇ )
  • the rotation speed determined by the speed determination unit 38 is sent to the drive unit 32, and the rotation of the transport rollers 18a and 19a is controlled.
  • the computer uses heating means in the slow cooling furnaces 12 and 13 so that the atmospheric temperature in the slow cooling furnaces 12 and 13 is maintained within a predetermined temperature range based on the ambient temperature detected by the temperature sensor 34. Automatic control.
  • the predetermined temperature range of the first slow cooling furnace 12 is set to, for example, 500 to 800 degrees.
  • the predetermined temperature range of the second slow cooling furnace 13 is set to 200 to 500 degrees, for example.
  • the speed determination unit 38 may determine the rotation speeds of the transport rollers 18a and 19a based on the content input by the operator.
  • the glass plate manufacturing apparatus 1 further includes an input unit (not shown) that receives an operator's input operation, and this input unit receives the rotation speeds of the transport rollers 18a and 19a input by the operator.
  • the storage unit 36 does not store temperature difference data, roller thermal expansion coefficient, peripheral speed distribution, reference values of the diameters of the transport rollers 18a and 19a, conditions for achieving the reference peripheral speed distribution, and the like. It is often calculated and input by an operator based on temperature difference data, roller thermal expansion coefficient, peripheral speed distribution, reference value of the diameter of each of the transport rollers 18a and 19a, conditions for achieving the reference peripheral speed distribution, etc.
  • the temperature difference data, the roller thermal expansion coefficient, the peripheral speed distribution, the reference value of the diameter of each of the transport rollers 18a and 19a, and the reference peripheral speed distribution may be calculated by an operator, and the calculated values are stored in the storage unit 36. May be remembered.
  • the plate-taking device 4 has a plate-making chamber (not shown) arranged on the downstream side of the second slow cooling furnace 13.
  • the glass ribbon B is cut at regular intervals, and the glass plate C is sampled.
  • the thickness of the glass plate C is, for example, 0.7 mm or less, or 0.5 mm or less.
  • flat panel displays have been required to be slim
  • flat display glass substrates such as liquid crystal displays and organic EL displays are also required to be thin.
  • the strength of the glass plate decreases as the thickness of the glass plate decreases, breakage easily occurs.
  • the thickness of the glass plate for flat display is preferably 0.01 to 1.0 mm, more preferably 0.05 to 0.7 mm, and 0.05 to 0.00 mm. More preferably, it is 5 mm.
  • strength falls as a thin glass plate, there exists a possibility that it may become easy to break by the damage
  • the length in the width direction of the glass plate C may be 1000 mm or more, 1500 mm or more, 2000 mm or more, 2500 mm or more
  • the length in the longitudinal direction may be 1000 mm or more, 1500 mm or more, 2000 mm or more, 2500 mm or more.
  • a relative speed difference slip
  • the relative speed difference tends to be easily generated, but the effect of preventing the relative speed difference from occurring is remarkable.
  • the effect of this invention becomes so useful that the length of the width direction of the glass plate C is 1500 mm or more, 2000 mm or more, 2500 mm or more.
  • the glass substrate for liquid crystal displays As a glass plate manufactured with the glass plate manufacturing method and glass plate manufacturing apparatus mentioned above, the glass substrate for liquid crystal displays is mentioned suitably, for example.
  • the following glass composition is illustrated as a glass composition of the glass substrate for liquid crystal displays. 50 to 70% by mass of SiO 2 B 2 O 3 0-15% by mass, Al 2 O 3 5 to 25% by mass, MgO 0-10% by mass, CaO 0-20% by mass, SrO 0-20% by mass, BaO 0-10% by mass, RO 5-20% by mass (provided that R is all components contained in the glass plate selected from Mg, Ca, Sr and Ba, and is at least one). It is preferable to contain.
  • non-alkali glass glass containing substantially no alkali component
  • a small amount of an alkali component may be included.
  • R ′ 2 O it exceeds 0.05% by mass and is 2.0% by mass or less, more preferably, R ′ 2 O exceeds 0.1% by mass and is 2.0% by mass or less (provided that R ′ is Li, Na And all components contained in the glass plate selected from K and K, which are at least one kind).
  • the rotational speed of each of the transport rollers 18a and 19a is controlled so as to compensate for the change in diameter that occurs in the transport rollers 18a and 19a. It is possible to suppress a difference in the relative speed between the peripheral speed of each of the transport rollers 18a and 19a and the transport speed of the glass ribbon B in the plurality of transport roller pairs 18 and 19 with higher accuracy. Thereby, the slip between the glass ribbon B and the conveyance rollers 18a and 19a can be prevented, and the quality of the glass plate surface can be improved.
  • the peripheral speed distribution of a plurality of pairs of transport rollers used for transporting the glass ribbon is corrected and set according to the temperature of the glass ribbon, so that the glass ribbon is not excessively prevented from being deformed. Moreover, it can prevent that a glass ribbon is pulled and a glass ribbon breaks because it becomes quicker than necessary.
  • Such an effect is obtained when the glass conveying speed is high (for example, when the conveying speed is 200 m / or more), or when the glass ribbon has a small strength and is easily deformed to a thickness of 0.5 mm or less, preferably 0.05 to This is more remarkable in the production of 0.5 mm thin glass.
  • the number of the plurality of conveying roller pairs is not particularly limited as long as it is at least two.
  • the temperature sensor detects the atmospheric temperature in the slow cooling furnaces 12 and 13 and uses this to calculate the glass ribbon temperature and the conveyance roller temperature, but the glass ribbon temperature and the conveyance roller temperature are directly measured. May be.
  • a radiation thermometer for continuously measuring the temperature of the glass ribbon may be used as the glass state detecting unit, and for continuously measuring the temperature of the conveying roller as the conveying roller state detecting unit.
  • the following thermometers may be used.
  • the peripheral speed ratio is not limited to that described above.
  • the speed determination unit 38 may calculate specific peripheral speeds of the transport rollers 18a and 19a as the peripheral speed distribution instead of the peripheral speed ratio.
  • the reference peripheral speed distribution and the corrected peripheral speed are also set as specific speed values.
  • the peripheral speed distribution in addition to adjusting the rotational speed so as to obtain a set peripheral speed distribution according to the change in the diameter of the transport roller, the peripheral speed distribution is changed to a reference peripheral speed distribution according to the temperature of the glass ribbon. Modify and set.
  • the reference peripheral velocity distribution need not be corrected in accordance with the current temperature of the glass ribbon.
  • the rotational speed of the transport rollers 18a and 19a is determined so as to compensate for the change in the diameter of the transport rollers that occurs in each roller of the transport roller pair 18 and 19, but in addition to the transport rollers 18a and 19a,
  • the rotational speed of each roller of the roller pair 17 is determined so as to compensate for the change in diameter of each roller of the roller pair 17 used as the cooling roller pair in the molding process.
  • Each roller of the roller pair 17 detects the state of each roller of the roller pair 17 using a detection unit such as the above-described conveyance roller state detection unit 37, and based on the detection result, each roller of the roller pair 17 is detected.
  • the rotational speed of each roller of the roller pair 17 is determined so as to compensate for the diameter change.
  • the peripheral speed of each roller of the roller pair 17 is set to an appropriate value so that the thickness distribution of the glass plate and the unevenness of the glass surface are minimized. Distribution and unevenness of the glass surface will be deteriorated. That is, when the peripheral speed of the roller pair 17 changes, the amount of the glass ribbon B stretched between the lower end of the molded body 10 and the roller pair 17 and the glass performed between the roller pair 17 and the conveying roller pair 18.
  • the rotational speed of each roller of the roller pair 17 is determined so as to compensate for a change in the diameter of each roller of the roller pair 17.
  • the rotational speed is determined so as to compensate for the change in the diameter of each roller of the roller pair 17 used as the cooling roller pair in the molding process in addition to the rollers of the transport roller pair 18 and 19, but
  • the rotational speed may be determined so as to compensate for a change in the diameter of each roller of at least one of the rollers of the roller pair 18, 19 and the roller pair 17.
  • slip of the glass ribbon B and the like can be suppressed, and generation of scratches on the surface of the glass ribbon B can be suppressed. If the glass is above the softening point, the glass ribbon B is not sufficiently solidified, so that slip is unlikely to occur. On the other hand, slip is likely to occur in the glass ribbon B below the softening point. For this reason, it is preferable to determine the rotational speed of the conveyance roller so as to compensate for the change in the diameter of the conveyance roller provided in the region where the central portion of the glass ribbon B is below the softening point.
  • At least the rotation speed of the conveying roller so as to compensate for a change in the diameter of the conveying roller provided in a temperature region where the temperature of the glass ribbon B is at least the glass transition point and below the softening point.
  • the effect of suppressing the plastic deformation of the glass ribbon B is increased. Therefore, it is preferable to determine the rotation speed of the conveying roller so as to compensate for a change in the diameter of the conveying roller provided in a temperature region in which at least the temperature of the central portion of the glass ribbon B is not less than the glass transition point and not more than the softening point.
  • the diameter of the conveyance roller provided in the temperature region where the temperature of the central portion of the glass ribbon B is not less than the glass transition point and not more than the softening point is likely to change, the diameter change of the conveyance roller provided in this region is compensated. It is preferable to determine the rotation speed of the transport roller. When the glass temperature is higher than the softening point, the compressive stress acting on the glass is instantly relieved, so that the glass ribbon B hardly undergoes wave-shaped plastic deformation. On the other hand, when the glass temperature is lower than the glass transition point, the viscosity of the glass ribbon B is sufficiently increased, so that the corrugated plastic deformation hardly occurs. Also, the upstream roller tends to change in roller diameter due to wear or thermal expansion. That is, it is preferable to determine the rotation speed of the conveying roller so as to compensate for a change in the diameter of the conveying roller provided at least in a temperature region where the temperature is not less than the glass transition point and not more than the softening point.
  • the rotation speed of the conveyance roller is determined so as to compensate for the change in the diameter of the conveyance roller provided in the temperature region where the temperature of the central portion of the glass ribbon B is from the annealing point (strain point—50 ° C.), By rotating the transport roller, plastic deformation of the glass ribbon can be suppressed.
  • the location of the conveyance roller that determines the rotation speed so as to compensate for the change in the diameter of the roller varies depending on which characteristic of the glass ribbon B is to be improved.
  • the conveyance roller state detection unit 37 according to the first embodiment includes a temperature sensor 34 that detects the temperature of the conveyance roller.
  • the conveyance roller state detection unit (hereinafter also simply referred to as a detection unit) 47 according to the second embodiment is illustrated in FIG.
  • a distance measurement sensor 44 for detecting the wear amount of the transport roller is included.
  • FIG. 6 is a block diagram illustrating the configuration of a control system that controls the rotational driving of the transport roller pairs 18 and 19 according to the second embodiment.
  • elements indicated by the same reference numerals as those in the first embodiment are not different from the configurations described in the first embodiment.
  • a plurality of distance measuring sensors 44 are provided corresponding to the respective transport roller pairs 18 and 19.
  • the distance measuring sensor 44 detects the driving shaft interval.
  • the drive shaft spacing is such that the drive shafts 18b and 19b connect the conveying rollers 18a and 19a on the same side with respect to the glass ribbon B, and the drive shaft 18b disposed opposite to the drive shafts 18b and 19b. , 19b.
  • the pair of transport rollers 18 and 19 sandwich the glass ribbon B in a state where the pair of transport rollers 18a and 19a are urged to each other.
  • the amount of wear of each of the transport rollers 18a and 19a is caused by the amount of change of the roller radius calculated according to the following formula from the roller radius when new, due to the wear of the transport rollers 18a and 19a.
  • the speed determination unit 48 of the detection control unit 40 determines the peripheral speed ratio of the peripheral speeds of the transport rollers 18a and 19a caused by the change in the radius of the transport rollers 18a and 19a due to the detected wear of the transport rollers 18a and 19a.
  • the rotational speeds of the transport rollers 18a and 19a are determined so as to compensate for the deviation.
  • the radius change calculated based on the wear state is used as the diameter change of the transport rollers 18a and 19a.
  • the wear roller 18a, 19a used in the first embodiment uses this wear state. It can also be applied together with the temperature of 19a. In this case, the diameters of the transport rollers 18a and 19a vary with the amount of wear and also with thermal expansion.
  • the rotational speeds of the transport rollers 18a and 19a can be calculated so that the peripheral speed of the transport rollers that changes with the change in diameter is maintained at the peripheral speed ratio. Furthermore, in addition to changes in the diameters of the transport rollers 18a and 19a, a change in the transport speed of the glass ribbon B that changes according to the temperature of the glass ribbon B due to the thermal expansion of the glass ribbon B as a state of the glass ribbon B is integrated and applied. You can also
  • the distance measurement sensor 44 replaces the distance between the drive shafts 18b and 19b of the transport roller pair 18 and 19 with the origin of the drive shafts 18b and 19b of the transport roller pair 18 and 19. It may be configured to detect the amount of wear by reading the deviation from the position.
  • the origin position is a center position where the drive shafts 18b and 19b are located when the transport rollers 18a and 19a are new, and is stored in the storage unit 46.
  • the amount of wear of the transport rollers 18a and 19a is detected using the deviation of the drive shafts 18b and 19b from the origin position of the pair of transport rollers 18 and 19, and the roller diameter of the transport rollers thus worn can be calculated.
  • the diameters of the transport rollers 18a and 19a are not limited to being calculated by the detection unit 47, and may be calculated by an operator based on the amount of wear, for example. In this case, based on the diameters of the transport rollers 18a and 19a calculated by the operator and input to the speed determination unit 48, the rotation speeds of the transport rollers 18a and 19a are calculated by the speed determination unit 48.
  • the rotational speeds of the transport rollers 18a and 19a may be further calculated based on the diameters of the transport rollers 18a and 19a calculated by the operator, and the calculation result may be input to the speed determination unit 48.
  • the rotation speed calculated or input by the speed determination unit 48 is determined by the speed determination unit 48 and transmitted to the drive unit 32.
  • the wear amount and the origin position of the transport rollers 18 a and 19 a may be calculated by the operator, and the calculated values may be stored in the storage unit 46.
  • a change in the diameter of the conveyance roller calculated based on the number of days of use of the conveyance rollers 18a and 19a is counted as a change in the diameter of the conveyance rollers 18a and 19a.
  • An apparatus may be used.
  • the device that counts the diameter change sends the usage days of the transport rollers 18 a and 19 a to the speed determination unit 48.
  • the speed determination unit 48 replaces the amount of wear from the new roller diameter when the transport rollers 18a and 19a stored in the storage unit 46 of the speed determination unit 48 are replaced in the past. The amount of wear per day is calculated based on these and the number of days used.
  • roller diameter new diameter-(amount of wear per day x number of days used)
  • speed determination unit 48 stores past replacement results and roller diameters when new for each of the transport rollers 18a and 19a.
  • the deviation from the peripheral speed ratio of the peripheral speeds of the transport rollers 18a and 19a caused by the change in the diameter of the transport rollers 18a and 19a can be compensated by a simpler method.
  • the amount of wear per day can be calculated by an operator and stored in the storage unit 46.
  • the diameter change of the transport rollers 18a and 19a due to the wear amount may be calculated by the operator and transmitted to the detection control unit 40 or the drive unit 32. Further, the wear amount of the roller diameter when it was replaced in the past and the number of days used until the replacement may be calculated by the operator, and the calculated value may be stored in the storage unit 46.
  • the transport rollers 18a and 19a are rotationally driven based on the rotational speed of the rollers determined based on the number of days of use of the transport rollers 18a and 19a so as to compensate for the change in the diameter of the rollers.
  • the state of the transport roller is not detected by the transport roller state detection unit, and the roller rotation speed is not determined based on the detection result, but the transport roller 18a. , 19a is different from the first and second embodiments in that the roller rotational speed is sequentially determined based on the number of days used.
  • modified example of the first embodiment or the first embodiment and the modified example of the second embodiment or the second embodiment can be combined.
  • the modification of the first embodiment or the first embodiment with the modification of the second embodiment or the second embodiment, the modification of the first embodiment or the first embodiment, the second embodiment or the first embodiment.
  • the deviation from the peripheral speed ratio can be compensated more accurately than in the case where the modification of the second embodiment is applied alone.
  • a glass plate is manufactured according to the following method using a conventional glass plate manufacturing apparatus and the glass plate manufacturing apparatus of the present embodiment, and the wavy uneven deformation generated in the glass plate is measured. did.
  • all used the glass plate manufacturing apparatus is the glass plate manufacturing apparatus 1 by the downdraw method shown in FIG.3 and FIG.4, and the glass used the aluminosilicate glass containing the component shown below. SiO 2 60% by mass, Al 2 O 3 19.5 mass%, B 2 O 3 10% by mass, CaO 5 mass%, 5% by mass of SrO, SnO 2 0.5% by mass.
  • the speed determining unit 38 determines the rotational speed of each of the transport rollers 18a and 19a, and controls the rotational drive of each of the transport rollers 18a and 19a based on the determined rotational speed. Then, a glass substrate for a liquid crystal display having a thickness of 0.7 mm and a length of 2000 mm in the width direction and a length of 2500 mm in the length direction was manufactured. The peripheral speeds of the transport rollers 18a and 19a as the peripheral speed ratio are all the same. The temperature of the glass ribbon and the temperature of the conveying roller were measured using a contact-type temperature sensor.
  • Example 2 a glass substrate for a liquid crystal display was manufactured in the same manner as in Example 1 except that the rotational speeds of the transport rollers 18a and 19a were determined by the speed determination unit 48 according to the second embodiment described above. Specifically, the wear amount of the transport rollers 18 a and 19 a was calculated using the driving shaft interval measured by the distance measuring sensor 44. In addition to the amount of change in roller diameter due to the amount of wear of the transport rollers 18a and 19a, the rotational speed of the transport rollers 18a and 19a was calculated in consideration of the amount of change in roller diameter due to the temperature of the transport rollers 18a and 19a.
  • the peripheral speeds of the respective transport rollers 18a and 19a are all changed to 1.1 times that of the first embodiment, and a 0.5 mm thick liquid crystal display is used.
  • a glass substrate for a liquid crystal display was produced in the same manner as in Example 1 except that a glass substrate for production was produced.
  • the speed determination unit was under the same conditions as in Examples 1 and 2 except that the rotation speed based on the state of the glass ribbon and the diameter change of the transport rollers 18a and 19a was not performed. went.
  • the obtained glass substrates for liquid crystal displays of Examples 1 to 3 and Comparative Examples 1 and 2 were visually checked for the presence or absence of scratches on the surface of the glass substrate for liquid crystal displays, and the waveform deformation was measured using a thickness gauge. .
  • the wave shape was assumed to satisfy the surface quality if it was within 0.4 mm in the thickness direction.
  • a surface quality of 0.2 mm or less was satisfied in the thickness direction.
  • Example 1 had a deformation
  • Example 2 deformation of about 0.1 mm occurred in the thickness direction.
  • Example 3 deformation of 0.02 mm or less occurred in the thickness direction.
  • the above-described surface quality was satisfied.

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Abstract

Lors de la production d'une feuille de verre, une matière première de verre est fondue pour créer du verre fondu, le verre fondu est moulé en utilisant le procédé d'étirage par le bas, un ruban de verre est formé, et le ruban de verre est étiré vers le bas et recuit tout en étant pris en sandwich entre une pluralité de paires de cylindres disposés le long de la direction de transport pour le ruban de verre. Durant le moulage, les deux extrémités du ruban de verre sont refroidies alors que le ruban de verre continue à être pris en sandwich entre les paires de cylindres et étiré vers le bas. Chaque cylindre dans une première paire de cylindres, qui est l'une des paires de cylindres utilisées soit dans le moulage soit le recuit, est mis en rotation sur la base d'une vitesse de rotation du cylindre déterminée de manière à compenser le changement de diamètre du cylindre.
PCT/JP2012/002144 2011-03-30 2012-03-28 Procédé de production de feuille de verre et dispositif de production de feuille de verre WO2012132425A1 (fr)

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CN2012800006628A CN102933514B (zh) 2011-03-30 2012-03-28 玻璃板的制造方法以及玻璃板制造装置
JP2012516255A JP5288386B2 (ja) 2011-03-30 2012-03-28 ガラス板の製造方法及びガラス板製造装置
KR1020127010848A KR101300909B1 (ko) 2011-03-30 2012-03-28 유리판의 제조 방법 및 유리판 제조 장치

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JP2017014054A (ja) * 2015-06-30 2017-01-19 ＡｖａｎＳｔｒａｔｅ株式会社 ガラス基板の製造方法
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JP2021095312A (ja) * 2019-12-18 2021-06-24 日本電気硝子株式会社 ガラス板の製造方法
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JP2015512850A (ja) * 2012-02-29 2015-04-30 コーニング インコーポレイテッド ガラス製造装置および方法
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WO2015135721A1 (fr) * 2014-03-13 2015-09-17 Schott Ag Procédé et dispositif permettant de réduire la convexité dans les verres minces
KR20160080054A (ko) 2014-12-29 2016-07-07 아반스트레이트 가부시키가이샤 유리 기판의 제조 방법
WO2016194922A1 (fr) * 2015-06-01 2016-12-08 日本電気硝子株式会社 Appareil de fabrication de produit en verre
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JP2021095312A (ja) * 2019-12-18 2021-06-24 日本電気硝子株式会社 ガラス板の製造方法
JP7417853B2 (ja) 2019-12-18 2024-01-19 日本電気硝子株式会社 ガラス板の製造方法
CN111039557A (zh) * 2019-12-26 2020-04-21 中国建材国际工程集团有限公司 一种传动系统及其控制方法
CN113277719A (zh) * 2021-04-30 2021-08-20 彩虹（合肥）液晶玻璃有限公司 一种平板玻璃板高控制装置
CN113277719B (zh) * 2021-04-30 2022-08-30 彩虹（合肥）液晶玻璃有限公司 一种平板玻璃板高控制装置

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JP5288386B2 (ja) 2013-09-11
TWI428296B (zh) 2014-03-01
KR101300909B1 (ko) 2013-08-27
CN102933514B (zh) 2013-10-23
JP2013151415A (ja) 2013-08-08
TW201247566A (en) 2012-12-01

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