JP2017065983A - Production method of glass sheet, and production apparatus of glass sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inhibit glass at the bottom end of a compact from being cooled by a gas flowing upward through a slit-like clearance where sheet glass passes.SOLUTION: A production method of a glass substrate includes a step for making molten glass overflow from a compact to shape sheet glass, a step for making the sheet glass pass downward through a first slit-like clearance and a second slit-like clearance, and a step for cooling the sheet glass in a lower space. The first clearance is formed by blocking members arranged at both sides in the thickness direction of the sheet glass below the compact. The second clearance is formed by insulation members arranged below the blocking members that partition a molding furnace chamber into an upper space where a molding furnace is disposed and the lower space. The blocking members are arranged so that the distance between the compact and the blocking members is larger than the maximum width of the first clearance, while the insulation members are arranged so that the distance between the compact and the insulation members is larger than the maximum width of the second clearance.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a glass plate manufacturing method and a glass plate manufacturing apparatus.

  Conventionally, the down draw method is used as one of the manufacturing methods of a glass plate. In the downdraw method, the molten glass overflowed from the molded body is diverted and flows down along the side surface of the molded body. Next, the molten glass is merged at the lower end of the formed body and formed into a glass plate. The formed glass plate is cooled while being conveyed downward in the vertical direction. In the cooling step, the glass plate transitions from the viscous region to the elastic region through the viscoelastic region.

  In a glass plate manufacturing apparatus using a downdraw method, generally, a cooling zone (lower space) in which a sheet glass separated from a molded body is cooled to the vicinity of the annealing point is an upper part where the molded body is disposed by a heat insulating member. A space is defined (see, for example, Patent Document 1). The heat insulation member controls the atmospheric temperature of the lower space to a desired temperature profile by suppressing the heat transfer from the upper space to the lower space and further suppressing the air flow rising from the lower space to the upper space. Be placed. Here, the desired temperature profile means a temperature distribution in the slow cooling zone so that the glass plate is not distorted. Therefore, the heat insulating member is important for forming a glass plate with less distortion by slowly cooling the glass plate.

JP 2008-88005 A

  The heat insulating member is provided with a slit-like gap through which the sheet glass descending from the molded body passes, and the heat insulating member is disposed with a gap from the sheet glass. When the air in the lower space is warmed by the sheet glass that has passed through the gap, an upward airflow is generated around the sheet glass. When the rising airflow passes through the gap between the heat insulating member and the sheet glass, the flow velocity increases. When the rising airflow with the increased flow velocity hits the lower end of the molded body, the glass is cooled. When the glass at the lower end of the molded body is cooled, there is a risk of causing variation (plate thickness deviation) in the sheet glass thickness.

  Then, an object of this invention is to suppress that the glass of the lower end of a molded object is cooled by the ascending airflow which raises the slit-shaped clearance gap which a sheet glass passes.

One aspect of the present invention is a method for producing a glass plate,
In the upper space of the molding furnace chamber surrounded by the furnace wall, the process of forming the sheet glass by overflowing the molten glass from the molded body,
A slit-shaped first gap formed by a blocking member disposed on both sides of the sheet glass in the thickness direction below the molded body, and disposed below the blocking member, and forming the molding furnace chamber Lowering the sheet glass through a slit-like second gap formed by a heat insulating member that partitions the upper space and the lower space in which the furnace is disposed;
A cooling step for cooling the sheet glass in the lower space,
Arranging the blocking member such that the distance between the molded body and the blocking member is larger than the maximum width of the first gap; and
The heat insulating material is arranged such that a distance between the molded body and the heat insulating member is larger than a maximum width of the second gap.

The cooling step includes a step of cooling the end portion in the width direction while transporting the sheet glass downward by sandwiching the end portion in the width direction of the sheet glass in the thickness direction by a cooling roller in the lower space. ,
It is preferable to arrange the heat insulating material so that the distance between the heat insulating material and the molded body is larger than the distance between the heat insulating material and the cooling roller.

  The blocking member extends in the thickness direction of the sheet glass, and it is preferable to control the radiant heat to the heat insulating member by moving the blocking member in the extending direction.

Another aspect of the present invention is a glass substrate manufacturing apparatus,
A molded body that is provided in a molding furnace chamber surrounded by a furnace wall and overflows molten glass to form a sheet glass;
A blocking member that is disposed below the molded body and on both sides in the thickness direction of the sheet glass in the molding furnace chamber, and forms a first gap through which the sheet glass passes;
Thermal insulation that is disposed below the blocking member in the molding furnace chamber, partitions the molding furnace chamber into an upper space and a lower space in which the molding furnace is disposed, and forms a second gap through which the sheet glass passes. A member,
A cooling device provided in the lower space for cooling the sheet glass,
The blocking member is disposed such that a distance between the molded body and the blocking member is larger than a maximum width of the first gap; and
The heat insulating member is arranged such that a distance between the molded body and the heat insulating member is larger than a maximum width of the second gap.

  According to the method for manufacturing a glass plate of the above-described aspect, the distance between the heat insulating member and the molded body is larger than the maximum width of the slit formed by the heat insulating material, and the blocking member and the molding are arranged on the upper portion of the molded body. Since the body and the distance are larger than the maximum width of the slit formed by the blocking member, the updraft that passes through the slit-shaped gap diffuses in the upper space before it hits the glass at the lower end of the molded body, and the shaped body is caused by the updraft. It can suppress that the glass of the lower end of is cooled

It is a flowchart which shows the manufacturing method of a glass substrate. It is the schematic of the manufacturing apparatus of a glass substrate. 1 is a schematic view showing a molding apparatus 200. FIG. FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. 3. It is an enlarged view of the V section of FIG.

Hereinafter, the manufacturing method of the glass substrate of this invention is demonstrated.
(Overall overview of glass substrate manufacturing method)
Drawing 1 is a figure showing an example of a process of a manufacturing method of a glass substrate of this embodiment. The glass substrate manufacturing method includes a melting step (ST1), a clarification step (ST2), a homogenization step (ST3), a supply step (ST4), a molding step (ST5), a slow cooling step (ST6), and a cutting step ( ST7) is mainly included. In addition, a grinding process, a polishing process, a cleaning process, an inspection process, a packing process, and the like may be included. The manufactured glass substrate is laminated in a packing process as necessary, and is transported to a supplier.

In the melting step (ST1), molten glass is made by heating the glass raw material.
In the clarification step (ST2), the molten glass is heated to generate bubbles containing oxygen, CO ₂ or SO ₂ contained in the molten glass. This bubble grows by absorbing oxygen generated by the reduction reaction of the clarifying agent (tin oxide or the like) contained in the molten glass, and floats on the liquid surface of the molten glass and is released. Thereafter, in the clarification step, by reducing the temperature of the molten glass, the reducing substance obtained by the reduction reaction of the clarifier undergoes an oxidation reaction. Thereby, gas components, such as oxygen in the bubble which remain | survives in molten glass, are reabsorbed in molten glass, and a bubble lose | disappears.

In the homogenization step (ST3), the glass component is homogenized by stirring the molten glass using a stirrer. Thereby, the composition unevenness of the glass which is a cause of striae or the like can be reduced. A homogenization process is performed in the stirring tank mentioned later.
In the supplying step (ST4), the stirred molten glass is supplied to the molding apparatus.

The molding step (ST5) and the slow cooling step (ST6) are performed by a molding apparatus.
In the forming step (ST5), the molten glass is formed into a sheet glass to make a flow of the sheet glass. An overflow downdraw method is used for molding.
In the slow cooling step (ST6), the sheet glass that has been formed and flowed is cooled to a desired thickness, so that internal distortion does not occur and warpage does not occur.
In the cutting step (ST7), the sheet glass after slow cooling is cut into a predetermined length to obtain a plate-like glass substrate. The cut glass substrate is further cut into a predetermined size to produce a glass substrate having a target size.

FIG. 2 is a schematic view of a glass substrate manufacturing apparatus that performs the melting step (ST1) to the cutting step (ST7) in the present embodiment. As shown in FIG. 2, the glass substrate manufacturing apparatus mainly includes a melting apparatus 100, a forming apparatus 200, and a cutting apparatus 300. The melting apparatus 100 includes a melting tank 101, a clarification pipe 102, a stirring tank 103, transfer pipes 104 and 105, and a glass supply pipe 106.
The melting tank 101 shown in FIG. 2 is provided with heating means such as a burner (not shown). A glass raw material to which a clarifying agent is added is charged into the melting tank, and a melting step (ST1) is performed. The molten glass melted in the melting tank 101 is supplied to the clarification tube 102 via the transfer tube 104.
In the clarification tube 102, the temperature of the molten glass MG is adjusted, and the clarification step (ST2) of the molten glass is performed using the oxidation-reduction reaction of the clarifier. Specifically, when the molten glass in the clarification tube 102 is heated, the bubbles containing oxygen, CO ₂ or SO ₂ contained in the molten glass absorb oxygen generated by the reductive reaction of the clarifier. It grows and floats on the liquid surface of the molten glass and is released into the gas phase space. Thereafter, by reducing the temperature of the molten glass, the reducing substance obtained by the reductive reaction of the fining agent undergoes an oxidation reaction. Thereby, gas components, such as oxygen in the bubble which remain | survives in molten glass, are reabsorbed in molten glass, and a bubble lose | disappears. The clarified molten glass is supplied to the stirring tank 103 via the transfer pipe 105.
In the stirring vessel 103, the molten glass is stirred by the stirring bar 103a, and the homogenization step (ST3) is performed. The molten glass homogenized in the stirring tank 103 is supplied to the molding apparatus 200 through the glass supply pipe 106 (supply process ST4).
In the forming apparatus 200, the sheet glass SG is formed from the molten glass by the overflow downdraw method (molding step ST5) and gradually cooled (slow cooling step ST6).
In the cutting device 300, a plate-like glass substrate cut out from the sheet glass SG is formed (cutting step ST7).

  Next, a detailed configuration of the molding apparatus 200 will be described.

(Molding equipment)
FIG. 3 is a schematic view showing the molding apparatus 200, and FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG.

  The furnace walls 203 and 204, the partition plates 260, and the partitions 261 to 264 of the molding apparatus 200 are made of a SiC member on which an oxide film is formed, a refractory material such as a refractory brick, a refractory heat insulation brick, a fiber-based heat insulation material, and a metal such as stainless steel. It is formed by the combination of. As shown in FIGS. 3 and 4, the internal space of the molding apparatus 200 is divided into a molding furnace 201 and a slow cooling furnace 202 below the molding furnace 201 by a partition plate 260. In the molding furnace 201, a molding process (ST5) is performed, and in the slow cooling furnace 202, a slow cooling process (ST6) is performed.

As shown in FIG. 4, the forming furnace 201 is partitioned from an external space outside in the horizontal direction by a vertical furnace wall 203. The molding furnace 201 is divided into an upper molding furnace 201A and a lower molding furnace 201B by a pair of atmosphere partition members 220 (heat insulating materials).
A molded body 210 is provided in the upper molding furnace 201A. The upper forming furnace 201A is provided with a heater 216 for heating the atmosphere, the formed body 210, and the molten glass MG flowing down the formed body 210.
Molten glass is supplied from the melting apparatus 100 to the compact 210 through the glass supply pipe 106 shown in FIG. The glass supply pipe 106 is made of platinum, heated by energization, and the temperature and viscosity of the molten glass supplied from the glass supply pipe 106 to the molded body 210 can be adjusted.

The formed body 210 is a long and narrow structure formed of firebrick or the like, and as shown in FIG. 4, has a vertical cross-sectional wedge shape whose width decreases from the upper end toward the lower end. A groove 212 serving as a flow path for guiding the molten glass MG is provided in the upper part of the molded body 210. The groove 212 is connected to the glass supply pipe 106, and the molten glass MG flowing through the glass supply pipe 106 flows along the groove 212. Since the depth of the groove 212 is shallower toward the downstream of the flow of the molten glass MG, the molten glass MG flowing through the groove 212 gradually overflows from the groove 212 and flows down along the side walls on both sides of the molded body 210. They merge at the lower end 213 of the molded body 210, merge and flow downward vertically. Thereby, the sheet glass SG which goes to the vertically downward direction from the molded object 210 within the shaping | molding apparatus 200 is made.
In addition, the temperature of the sheet glass SG just under the lower end part 213 of the molded body 210 is a temperature corresponding to a viscosity of 10 ^5.7 to 10 ^7.5 poise, for example, 1000 to 1130 ° C.
Guide members 214 and 215 are provided at both ends in the length direction of the molded body 210. The guide members 214 and 215 prevent the molten glass overflowing from the groove 212 from overflowing in the direction of both ends of the molded body 210 (left and right direction in FIG. 3). The guide members 214 and 215 are made of, for example, a platinum group metal.

A heater 216 for heating the inside of the upper molding furnace 201A is provided in the upper molding furnace 201A. The temperature in the upper molding furnace 201A is adjusted by a heater 216 within a predetermined temperature range in which the molten glass flowing down from the molded body 210 is kept sufficiently low in viscosity.
In the upper molding furnace 201 </ b> A, a pair of blocking members 217 are provided below the heater 216 and above the atmosphere partition member 220. The pair of blocking members 217 are provided on both sides in the thickness direction of the sheet glass SG (the left side and the right side in FIG. 4), and the interval (first first) through which the sheet glass SG passes in the thickness direction of the sheet glass SG. It is arranged with a gap. The first interval is sufficiently larger than the thickness of the sheet glass SG.
The blocking member 217 can move in the thickness direction of the sheet glass SG (the left-right direction in FIG. 4). By moving the blocking member 217 in the thickness direction of the sheet glass SG, the radiant heat from the heater 216 is changed to the atmosphere partition member 220. The amount to reach can be adjusted. The blocking member 217 plays a role of preventing the temperature of the atmosphere partition member 220 from rising excessively.

  The pair of atmosphere partition members 220 is provided near the lower end portion 213 of the molded body 210 and divides the internal space of the molding furnace 201 into an upper molding furnace 201A and a lower molding furnace 201B. The pair of atmosphere partition members 220 is a plate-like heat insulating material, and is provided on both sides in the thickness direction of the sheet glass SG (the left side and the right side in FIG. 4), and in the thickness direction of the sheet glass SG, It arrange | positions at intervals (2nd clearance gap) through which the sheet glass SG passes. The second interval is sufficiently larger than the thickness of the sheet glass SG. The atmosphere partition member 220 partitions the internal space of the molding apparatus 200, thereby blocking heat transfer between the upper molding furnace 201 </ b> A above the atmosphere partition member 220 and the lower molding furnace 201 </ b> B below.

The lower molding furnace 201B is provided with a pair of cooling rollers 230 and a cooling device 240.
The cooling roller 230 and the cooling device 240 are provided below the atmosphere partition member 220.
As shown in FIGS. 3 and 4, the pair of cooling rollers 230 are provided on both sides in the thickness direction of the sheet glass SG so that the sheet glass SG is sandwiched from both sides in the thickness direction and pulled downward. Yes. The cooling roller 230 cools both ends in the width direction of the sheet glass SG so as to decrease to a temperature equal to or lower than a temperature corresponding to a viscosity of about 10 ^14.5 poise or more. The cooling roller 230 is hollow and is rapidly cooled by supplying a cooling medium (for example, air) to the inside.
The cooling roller 230 is provided so as to be movable in the width direction of the sheet glass SG (the left-right direction in FIG. 3). By adjusting the cooling position of the sheet glass SG by the cooling roller 230, the width of the sheet glass SG can be adjusted. By adjusting the width of the sheet glass SG, the width of the molten glass flowing down from the molded body 210 (the length in the left-right direction in FIG. 3) can be adjusted.

The cooling device 240 cools the central portion in the width direction of the sheet glass SG from a temperature higher than the softening point to the vicinity of the annealing point. Here, the center part of the sheet glass SG is an area | region except the object cut | disconnected after sheet glass shaping | molding, and is an area | region manufactured so that the plate | board thickness of the sheet glass SG may become uniform. The cooling device 240 is composed of, for example, three units in the vertical direction. The upper unit rapidly cools the sheet glass SG to the vicinity of the softening point, and the sheet glass SG is gently cooled by the middle unit and the lower unit. Cool to near annealing point. The cooling device 240 cools the central portion in the width direction of the sheet glass SG so as to be lowered to a temperature equal to or lower than a temperature corresponding to a viscosity of about 10 ^9.0 poise or more.

  As shown in FIG. 4, the slow cooling furnace 202 is partitioned from an external space outside in the horizontal direction by a vertical furnace wall 204. The slow cooling furnace 202 is partitioned from the lower molding furnace 201B by a partition plate 260 provided horizontally. The internal space of the slow cooling furnace 202 is divided into a plurality of sections Ca to Cf by a partition wall 261 provided horizontally at intervals in the vertical direction. In addition, in this embodiment, although the example in which the inside of the slow cooling furnace 202 is divided into six divisions Ca-Cf is demonstrated, the number of divisions is arbitrary.

In the sections Ca to Cf of the slow cooling furnace 202, a conveying member 250, a temperature adjustment device 251 and a pressure sensor 270 are provided, respectively.
In the lower forming furnace 201B and the slow cooling furnace 202, the sheet glass SG is cooled by the cooling roller 230, the cooling device 240, and the temperature adjusting device 251 so as to have a temperature distribution corresponding to a predesigned temperature profile. The sheet glass SG cooled in the slow cooling furnace 202 is cut by a cutting device 300 provided in the lower part of the slow cooling furnace 202.

In the viscous region, for example, the temperature profile (first profile) is designed such that the temperature of the end in the width direction of the sheet glass SG is lower than the temperature of the central region and the temperature of the central region is uniform. Thereby, the plate | board thickness of the sheet glass SG can be made uniform, suppressing the shrinkage | contraction of the width direction.
In the viscoelastic region, for example, a temperature profile (second profile) is designed such that the temperature of the sheet glass SG gradually decreases in the width direction from the center toward the end.
In the temperature region in the vicinity of the glass strain point, the temperature profile is designed such that the temperature at the end in the width direction of the sheet glass SG and the temperature at the center are substantially uniform.
By managing the temperature of the sheet glass SG so as to follow the above-described designed temperature profile, the warp and distortion (residual stress) of the sheet glass SG can be reduced. In addition, the center area | region of the sheet glass SG is an area | region including the target part which makes plate | board thickness uniform, and the edge part of the sheet glass SG is an area | region including the target part cut | disconnected after manufacture.

The external space SA above the molding furnace 201 and the external space SB outside the horizontal direction of the molding furnace 201 are separated by a partition wall 262 provided horizontally at the upper end of the molding furnace 201. The external spaces SA and SB are provided with a pressure sensor 270 and a pressure control device 280, respectively, and the pressures in the external spaces SA and SB are adjusted within a predetermined range.
The external space on the outer side in the horizontal direction of the slow cooling furnace 202 is separated from the external space SB by a partition wall 263 horizontally provided at the height of the upper end of the slow cooling furnace 202, and is provided horizontally with a space in the vertical direction. The partition 264 is divided into a plurality of external sections Sa to Sf. The number of the partition walls 264 is preferably equal to the number of the partition walls 261, and the vertical interval at which the partition walls 264 are provided is preferably equal to the vertical interval at which the partition walls 261 are provided. That is, it is preferable to provide the partition walls 261 and 264 such that the plurality of internal sections Ca to Cf in the slow cooling furnace 202 are at the same height as the plurality of external sections Sa to Sf in the external space of the slow cooling furnace 202.
The external compartments Sa to Sf are provided with a pressure sensor 270 and a pressure control device 280, respectively, and the pressures in the external compartments Sa to Sf are adjusted within a predetermined range.
The pressure control device 280 is, for example, a blower that supplies outside air into the external spaces SA and SB or the external compartments Sa to Sf, or discharges gas inside the external spaces SA and SB or the external compartments Sa to Sf to the outside.

  FIG. 5 is an enlarged view of a portion V in FIG. In the present embodiment, the pair of blocking members 217 are located sufficiently away from the molded body 210. If the shortest distance between the molded body 210 and the blocking member 217 is D1, and the maximum width of the first gap is D2, the blocking member 217 is arranged so that D1> D2.

  Further, in the present embodiment, the pair of atmosphere partition members 220 is at a position sufficiently away from the molded body 210. When the shortest distance between the molded body 210 and the atmosphere partition member 220 is D3 and the maximum width of the second gap is D4, the atmosphere partition member 220 is arranged so that D3> D4.

  Ascending air current is generated when the gas around the sheet glass SG is heated by the sheet glass in the lower forming furnace 201B. When this updraft passes through the gap between the atmosphere partition member 220 and the sheet glass SG and flows into the upper molding furnace 201A, the glass at the lower end of the molded body 210 may be cooled by the updraft.

  In the present embodiment, since the blocking member 217 is arranged so that D1> D2, the rising air current rising between the blocking member 217 and the sheet glass SG is between the molded body 210 and the blocking member 217. It diffuses in the atmosphere of the upper molding furnace 201A. Further, the rising air is heated by the atmosphere of the upper molding furnace 201A while the rising air flows from the position of the blocking member 217 to the position of the lower end 213 of the molded body 210. It can suppress that the glass of the part 213 is cooled rapidly.

  Moreover, in this embodiment, since the atmosphere partition member 220 is arrange | positioned so that it may become D3> D4, the ascending airflow which raises between the atmosphere partition member 220 and the sheet glass SG is the molded object 210 and an atmosphere partition member. It diffuses in the atmosphere of the upper molding furnace 201A between 220. Further, since the rising air is heated by the atmosphere of the upper molding furnace 201A while the rising air flows from the position of the atmosphere partition member 220 to the position of the lower end 213 of the molded body 210, the lower end of the molded body 210 is heated by the rising air current. It can suppress that the glass of this is cooled.

  Thus, in this embodiment, since it can suppress that the glass of the lower end part 213 of the molded object 210 is cooled by an updraft, the sheet glass SG is made to follow the designed temperature profile. The influence of the updraft when managing the temperature can be reduced.

  Further, when the shortest distance between the atmosphere partition member 220 and the cooling roller 230 is D5, it is preferable to adjust the height position of the atmosphere partition member 220 so that D3> D5.

  As described above, according to the present embodiment, the highly viscous glass attached to the molded body 210 can be removed by varying the width or tension of the molten glass flowing down from the molded body 210. For this reason, it can suppress that a surface unevenness | corrugation is produced | generated on the sheet glass SG resulting from the highly viscous glass adhering to the molded object 210. FIG.

  As mentioned above, although the manufacturing method of the glass substrate of this invention was demonstrated in detail, this invention is not limited to the said embodiment, In the range which does not deviate from the main point of this invention, you may make various improvement and a change. Of course.

  For the glass substrate produced by the method for producing a glass substrate of the present embodiment, an alkali-free boroaluminosilicate glass having a high strain point and a slow cooling point and good dimensional stability or a glass containing a trace amount of alkali is used.

The glass substrate to which this embodiment is applied is made of an alkali-free glass having the following composition, for example.
SiO _2: 56-65% by weight
Al ₂ O ₃ : 15-19% by mass
B ₂ O _3: 8-13 wt%
MgO: 1-3% by mass
CaO: 4-7% by mass
SrO: 1-4% by mass
BaO: 0-2 mass%
Na ₂ O: 0-1% by mass
K ₂ O: 0-1 wt%
As ₂ O ₃ : 0-1% by mass
Sb ₂ O _3: 0-1 wt%
SnO ₂ : 0-1% by mass
Fe ₂ O ₃ : 0-1% by mass
ZrO ₂ : 0-1% by mass

The glass substrate manufactured by this embodiment is suitable for the glass substrate for a display containing the glass substrate for flat panel displays. It is suitable for an oxide semiconductor display glass substrate using an oxide semiconductor such as IGZO (indium, gallium, zinc, oxygen) and an LTPS display glass substrate using an LTPS (low temperature polysilicon) semiconductor. Moreover, the glass substrate manufactured by this embodiment is suitable for the glass substrate for liquid crystal displays by which it is calculated | required that content of an alkali metal oxide is very small. Moreover, it is suitable also for the glass substrate for organic EL displays. In other words, the manufacturing method of the glass substrate of this embodiment is suitable for manufacture of the glass substrate for displays, and is especially suitable for manufacture of the glass substrate for liquid crystal displays.
Moreover, the glass substrate manufactured by this embodiment is applicable also to a cover glass, the glass for magnetic discs, the glass substrate for solar cells, etc.

DESCRIPTION OF SYMBOLS 100 Melting apparatus 101 Melting tank 102 Clarification pipe 103 Stirring tank 103a Stirrer 104 Transfer pipe 105 Transfer pipe 106 Glass supply pipe 200 Molding apparatus 201 Molding furnace 201A Upper molding furnace 201B Lower molding furnace 202 Slow cooling furnace 203, 204 Furnace wall 210 Molded body 212 Groove 213 Lower end portion 214, 215 Guide member 216 Heater 217 Blocking member 220 Atmosphere partition member 230 Cooling roller 240 Cooling device 250 Transport member 251 Temperature adjusting device 260 Partition plate 261-264 Partition wall 270 Pressure sensor 280 Pressure control device 300 Cutting device Ca -Cf Internal compartment MG Molten glass SA, SB External space SG Sheet glass Sa-Sf External compartment

Claims (4)

In the upper space of the molding furnace chamber surrounded by the furnace wall, the process of forming the sheet glass by overflowing the molten glass from the molded body,
A slit-shaped first gap formed by a blocking member disposed on both sides of the sheet glass in the thickness direction below the molded body, and disposed below the blocking member, and forming the molding furnace chamber Lowering the sheet glass through a slit-like second gap formed by a heat insulating member that partitions the upper space and the lower space in which the furnace is disposed;
A cooling step for cooling the sheet glass in the lower space,
Arranging the blocking member such that the distance between the molded body and the blocking member is larger than the maximum width of the first gap; and
The method for producing a glass substrate, wherein the heat insulating material is arranged such that a distance between the molded body and the heat insulating member is larger than a maximum width of the second gap. The cooling step includes a step of cooling the end portion in the width direction while transporting the sheet glass downward by sandwiching the end portion in the width direction of the sheet glass in the thickness direction by a cooling roller in the lower space. ,
The said heat insulating material is arrange | positioned so that the distance of the said heat insulating material and the said molded object may become larger than the distance of the said heat insulating material and the said cooling roller, The manufacturing of the glass substrate of Claim 1 characterized by the above-mentioned. Method.   3. The glass substrate according to claim 1, wherein the blocking member extends in a thickness direction of the sheet glass, and controls the radiant heat to the heat insulating member by moving the blocking member in the extending direction. Production method. A molded body that is provided in a molding furnace chamber surrounded by a furnace wall and overflows molten glass to form a sheet glass;
A blocking member that is disposed below the molded body and on both sides in the thickness direction of the sheet glass in the molding furnace chamber, and forms a first gap through which the sheet glass passes;
Thermal insulation that is disposed below the blocking member in the molding furnace chamber, partitions the molding furnace chamber into an upper space and a lower space in which the molding furnace is disposed, and forms a second gap through which the sheet glass passes. A member,
A cooling device provided in the lower space for cooling the sheet glass,
The blocking member is disposed such that a distance between the molded body and the blocking member is larger than a maximum width of the first gap; and
The said heat insulation member is arrange | positioned so that the distance of the said molded object and the said heat insulation member may become larger than the maximum width of a said 2nd clearance gap, The manufacturing apparatus of the glass substrate characterized by the above-mentioned.

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