WO2017002626A1

WO2017002626A1 - Glass substrate production method and glass substrate production device

Info

Publication number: WO2017002626A1
Application number: PCT/JP2016/067823
Authority: WO
Inventors: 仁志月向
Original assignee: ＡｖａｎＳｔｒａｔｅ株式会社; 安瀚視特股▲ふん▼有限公司
Priority date: 2015-06-30
Filing date: 2016-06-15
Publication date: 2017-01-05
Also published as: CN107735369A; KR102025004B1; JPWO2017002626A1; TW201708131A; KR20180008710A; JP6767866B2; TWI703099B; CN107735369B

Abstract

When producing a glass substrate, after causing molten glass that has overflowed from the upper section of a molded body in the upper space of a molding furnace chamber that has been heated to flow down along both side surfaces of the molded body, the molten glass is caused to merge at the lower end of the molded body to create sheet glass to be conveyed, and thereafter, the sheet glass is cooled. At such time, the molten glass or the sheet glass is blocked from receiving heat from the upper space in parts with a shielding member in the width direction which is orthogonal to the conveyance direction of the molten glass or the glass sheet, thereby adjusting the temperature distribution of the molten glass or the sheet glass in the width direction.

Description

Glass substrate manufacturing method and glass substrate manufacturing apparatus

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

Conventionally, the down draw method has been used as one of the methods for producing 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. The molten glass that is diverted and flows down joins at the lower end of the molded body and is 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.

The molten glass flowing down along the side of the molded body leaves the molded body, and at the same time, the glass plate contracts in the width direction due to surface tension. Due to this shrinkage, a thickness deviation or unevenness occurs in the glass plate. In Patent Document 1, between the formed body and the pulling roller below the formed body, in the vicinity of the edge in the width direction of the glass plate, a cooling unit provided apart from the glass plate is used. A method for adjusting the temperature of the edge and suppressing the shrinkage of the glass plate is disclosed. Thereafter, the glass plate whose shrinkage is suppressed is formed through the slow cooling space. In this slow cooling space, the ambient temperature is controlled so as to have a desired temperature profile (a temperature distribution that does not cause distortion in the glass plate), and the thickness deviation of the glass plate is suppressed. On the other hand, in recent years, in glass substrates for liquid crystal display devices, specifications (quality) required for deviations in the thickness of glass plates have become strict.

The plate thickness deviation is a thickness deviation generated in the width direction of the glass plate, and is continuously generated in the conveyance direction of the glass plate, and the generation position in the width direction of the glass plate is often constant. In order to satisfy the recent strict requirements for sheet thickness deviation, it is not sufficient to perform thermal management in a slow cooling space.

Japanese Patent Laid-Open No. 5-12427

Therefore, an object of the present invention is to provide a glass plate manufacturing method and a glass plate manufacturing apparatus capable of suppressing a plate thickness deviation that occurs along the conveying direction of the glass plate.

One embodiment of the present invention is a method for manufacturing a glass substrate. The manufacturing method is
After the molten glass overflowed from the upper part of the molded body in the upper space of the heated molding furnace chamber is caused to flow down along both side surfaces of the molded body, the molten glass is joined at the lower end of the molded body. A molding process for making the sheet glass to be conveyed;
A cooling step for cooling the sheet glass;
In the width direction orthogonal to the conveying direction of the molten glass or the sheet glass, the molten glass or the sheet glass is partially blocked by the shielding member from receiving heat from the upper space, so that the molten glass or Adjusting the temperature distribution in the width direction of the sheet glass.

In the adjustment step, the difference t _max −t _min between the maximum glass plate thickness t _max and the minimum glass plate thickness t _min obtained for each 20 mm in the width direction of the sheet glass obtained in the cooling step is It is preferable to adjust the temperature distribution in the width direction of the molten glass or the sheet glass so as to be 15 μm or less.

The difference t _max −t _min between the maximum glass plate thickness t _max and the minimum glass plate thickness t _min obtained every 100 mm in the glass width direction of the sheet glass obtained in the cooling step is 20 μm or less, respectively. In the adjusting step, it is preferable to adjust the temperature distribution in the width direction of the molten glass or the sheet glass.

At this time, when a concave portion is generated in the molten glass or the sheet glass and a thickness deviation occurs, in the adjusting step, the molten glass or the sheet glass is heated in the upper space at the generation position in the width direction of the concave portion. It is preferable to adjust the temperature distribution by bringing the shielding member closer at the generation position.

When a convex part occurs in the molten glass or the sheet glass and a thickness deviation occurs, in the adjustment step, the molten glass or the sheet glass is positioned at both sides sandwiching the generation position in the width direction of the convex part. It is preferable that the temperature distribution is adjusted by bringing the shielding member closer at the positions on both sides so as not to receive heat from the upper space.

It is preferable that the separation distance between the shielding member and the surface of the sheet glass is adjusted according to the degree of the thickness deviation.

The adjusting step is preferably performed when the viscosity of the molten glass or the sheet glass is 10 ^7.6 poise or less.

It is preferable that the adjustment step is performed from the lower end of the molded body to a position separated by 50 mm downstream or upstream in the conveying direction of the molten glass or the sheet glass.

The cooling step includes cooling both end portions of the sheet glass with a cooling roller in order to prevent the sheet glass from shrinking in the width direction of the sheet glass;
The upper space is located on the upstream side in the conveyance direction of the sheet glass with respect to the partition plate that partitions from the lower space in which the cooling roller is provided,
The shielding member is preferably provided in the upper space.

The molding furnace chamber allows the sheet glass to enter the lower space through a slit hole between the partition plates,
The shielding member is preferably supported by the partition plate.

It is preferable to adjust the position in the transport direction in which the temperature distribution is adjusted by using the shielding member by changing the thickness or height of the partition plate.

Another embodiment of the present invention is a glass substrate manufacturing apparatus. The manufacturing equipment
A molding furnace chamber;
A molded body that is provided in the upper space of the molding furnace chamber, overflows the molten glass and flows down along both side surfaces, and then forms a sheet glass that is conveyed by joining the molten glass at the lower end, and
A heat source for heating the walls of the upper space and the atmosphere in the upper space;
The molten glass or the sheet glass is partially blocked from receiving heat from the upper space in the width direction perpendicular to the conveying direction of the molten glass or the sheet glass. And a shielding member that adjusts the temperature distribution in the width direction.

According to the glass plate manufacturing method and the glass plate manufacturing apparatus described above, the molten glass flowing on the side surface of the molded body, or the width direction orthogonal to the conveying direction of the sheet glass formed by separating the molten glass from the lower end of the molded body. By adjusting the temperature distribution, the plate thickness deviation can be suppressed.

It is a schematic block diagram of an example of the glass plate manufacturing apparatus of this embodiment. It is a cross-sectional schematic block diagram of an example of the shaping | molding apparatus of this embodiment. It is a side schematic block diagram of an example of the shaping | molding apparatus of this embodiment. It is a figure which expands and demonstrates an example of the upper space of the molding furnace chamber of this embodiment by which the molded object is arrange | positioned. It is a figure explaining an example of adjustment of the temperature distribution of the sheet glass using the shielding member of this embodiment. It is a figure explaining the other example of adjustment of the temperature distribution of the sheet glass using the shielding member of this embodiment.

Hereinafter, the manufacturing method and glass plate manufacturing apparatus of the glass plate concerning this embodiment are demonstrated. FIG. 1 is a schematic configuration diagram of an example of a glass plate manufacturing apparatus according to the present embodiment.
The glass plate manufacturing apparatus 100 is comprised from the melting tank 200, the clarification tank 300, and the shaping | molding apparatus 400, as shown in FIG. In the melting tank 200, the glass raw material is melted to produce molten glass. The molten glass generated in the melting tank 200 is sent to the clarification tank 300. In the clarification tank 300, bubbles contained in the molten glass are removed. The molten glass from which bubbles have been removed in the clarification tank 300 is sent to the molding apparatus 400. In the forming apparatus 400, the sheet glass G is continuously formed from the molten glass by, for example, an overflow down draw method. Thereafter, the formed sheet glass G is cooled and cut into a glass plate having a predetermined size. The sheet glass G is, for example, a glass substrate for a display (for example, a glass substrate for a liquid crystal display, a glass substrate for a plasma display, a glass substrate for an organic EL display), a glass substrate for tempered glass such as a cover glass or a magnetic disk, or a roll. Used as a glass substrate on which electronic devices such as a glass substrate and a semiconductor wafer are laminated.

Next, a detailed configuration of the molding apparatus 400 will be described. FIG. 2 is a schematic cross-sectional configuration diagram of an example of the molding apparatus, and FIG. 3 is a schematic side configuration diagram of an example of the molding apparatus. FIG. 4 is an enlarged view illustrating an example of the upper space of the molding furnace chamber in which the molded body is arranged.
In the forming apparatus 400, a forming step for producing a sheet glass by an overflow downdraw method, a cooling step for cooling the formed sheet glass, and a temperature in the width direction perpendicular to the conveying direction of the molten glass or the sheet glass when producing the sheet glass. An adjustment step of adjusting the distribution is performed.
As shown in FIGS. 2 to 4, the forming apparatus 400 includes a formed body 10, a partition plate 20, a cooling roller 30,

heat insulating members

40a, 40b,..., 40h, and

feed rollers

50a, 50b,. , 50h and temperature control units (temperature control devices) 60a, 60b,..., 60h. The molding apparatus 400 includes an upper space 410 in the molding furnace chamber that is a space above the partition plate 20, a lower space 42a in the molding furnace chamber that is a space immediately below the partition plate 20, and a space below the lower space 42a. And a certain slow cooling zone 420. The slow cooling zone 420 has a plurality of

slow cooling spaces

42b, 42c,. The lower space 42a, the slow cooling space 42b, the slow cooling space 42c,..., The slow cooling space 42h are stacked in this order from the top to the bottom in the vertical direction. The upper space 410, the lower space 42a, and the slow cooling zone 420 are surrounded by a refractory material and / or a heat insulating material building (not shown), and the cooling process of the sheet glass G is performed in the lower space 42a and the slow cooling zone 420. The temperature control unit 60a or the like controls the temperature suitable for forming and cooling the sheet glass G.

As shown in FIG. 4, the upper space 410 is separated from the external space by a furnace wall 412 made of a refractory material and a heat insulating material. On the inner wall surface of the furnace wall 412 facing the upper space 410, the atmosphere of the upper space 410 and the furnace wall 412 are heated according to the installation position of the molded body 10 in the height direction (up and down direction in FIG. 4). A plurality of heaters 414 are provided.

The molded body 10 is a member having a substantially wedge-shaped cross-sectional shape as shown in FIG. 2 or FIG. The molded body 10 is disposed in the upper space 410 so that the substantially wedge-shaped lower end 11 is at the lowest position. As shown in FIGS. 2 and 4, a groove 12 is formed on the upper end surface of the molded body 10. The grooves 12 are formed in the longitudinal direction of the molded body 10, that is, in the left-right direction on the paper surface of FIG. 3. A glass supply tube 14 is provided at one end of the groove 12. The groove 12 is formed so as to gradually become shallower as it approaches the other end from one end where the glass supply pipe 14 is provided. Guides that prevent the molten glass MG from protruding from the side walls are attached to both ends in the longitudinal direction of the molded body 10. The molten glass MG overflowing from the groove 12 flows on both side surfaces 13a and both inclined surfaces 13b of the molded body 10, and is fused at the lower end 11 to form the sheet glass G. The width direction of the molten glass MG or the sheet glass G refers to a direction orthogonal to the conveying direction in the direction of the surface of the molten glass MG or the surface of the sheet glass G. Here, at the end portions on both sides of the sheet glass G, portions where the thickness is thicker than the plate thickness at the center in the width direction of the sheet glass G are formed. Moreover, the center area | region which is the area | region of the width direction pinched | interposed by the edge part of the both sides of the sheet glass G is thin compared with an edge part, and heat retention is small. For this reason, the amount of retained heat is likely to change due to temperature unevenness or the like, and warpage and distortion are likely to occur. For this reason, it is necessary to strictly manage the cooling amount in the central region. In the present embodiment, by adjusting the temperature and viscosity adjustment accuracy of the molten glass MG and the sheet glass G that are fused at the lower end 11 of the molded body 10, the sheet thickness deviation including the striae that are irregularities of the sheet glass G is suppressed. . Hereinafter, the glass before fusing at the lower end 11 of the molded body 10 is referred to as molten glass MG, and the glass after fusing at the lower end 11 is referred to as sheet glass G. In a thin glass, the occurrence of a plate thickness deviation is not preferable, and in particular, in the case of a glass plate used for a glass substrate for a display, the generation of a partial plate thickness deviation is not preferable because it greatly affects the display accuracy of the display.

The partition plate 20 is a plate-like heat insulating material disposed in the vicinity of the lower end 11 of the molded body 10. The partition plate 20 is arranged so that the position of the lower end in the height direction is located below the position of the lower end 11 of the molded body 10 in the height direction. The partition plates 20 are disposed on both sides of the sheet glass G in the thickness direction, as shown in FIGS. The partition plate 20 suppresses heat transfer from the upper space 410 to the lower space 42a by partitioning the upper space 410 of the molding furnace chamber and the lower space 42a of the molding furnace chamber. The upper space 410 and the lower space 42a are separated from each other by the partition plate 20 that is a heat insulating material. The temperature in the space in the upper space 410 and the lower space 42a is such that the two spaces do not affect each other. This is to perform control. In addition, the partition plate 20 is arranged with the interval between the sheet glass G and the partition plate 20 adjusted in advance so as to suppress the volume flow rate of the rising airflow entering the upper space 410 from the slow cooling zone 420.

The cooling roller 30 is disposed in the vicinity of the partition plate 20 in the lower space 42a. The cooling rollers 30 are disposed on both sides of the sheet glass G in the thickness direction, sandwich the sheet glass G in the thickness direction, and serve to cool the end of the sheet glass G while conveying the sheet glass G downward. Bear. The molten glass MG flowing down along the side surface 13a and the inclined surface 13b of the molded body 10 leaves the lower end 11 of the molded body 10, and at the same time, the sheet glass G contracts in the width direction due to surface tension.
The cooling roller 30 sandwiches portions adjacent to the center region side with respect to both end portions of the sheet glass G contracting in the width direction, thereby preventing the sheet glass G from contracting in the width direction. Cool G. Thereby, the shrinkage | contraction to the width direction of the sheet glass G is suppressed, and the distortion which arises in the sheet glass G, plate | board thickness deviation, and an unevenness | corrugation are suppressed. However, when the viscosity of the sheet glass G at the lower end 11 of the molded body 10 is high and the contraction rate of the sheet glass G is large, the cooling roller 30 may not be able to suppress distortion, plate thickness deviation, and unevenness. For this reason, in this embodiment, by adjusting the thermal management at the lower end 11 of the molded body 10 with the shielding member 80, the accuracy of thermal management can be improved and the plate thickness deviation can be suppressed. That is, the step of cooling the sheet glass includes cooling the end portions on both sides of the sheet glass G with the cooling roller 30 in order to prevent the sheet glass G from shrinking in the width direction of the sheet glass G. The space 410 is located on the upstream side in the conveyance direction of the sheet glass G with respect to the partition plate 20 that partitions from the lower space 42 a where the cooling roller 30 is provided, and the shielding member 80 is provided in the upper space 410.

The

heat insulating members

40a, 40b,..., 40h are arranged in the slow cooling zone 420 in the slow cooling zone 420 with respect to the sheet glass G transport direction (vertically downward). -Dividing into 42h and suppressing the heat transfer in each of the gradually cooled spaces. In addition, the

heat insulating members

40a, 40b,..., 40h are plate-like members disposed below the cooling roller 30 and on both sides in the thickness direction of the sheet glass G, and the sheet glass G in the transport direction. It has a slit-like space to guide. As described above, the lower space 42 a and the slow cooling zone 420 are surrounded by a refractory material and / or a heat insulating material building (not shown), but the sheet glass G is carried out to the slow cooling zone 420. There is a slit-like space, and there are some fine gaps in the heat insulation building. For this reason, due to the chimney effect, an ascending airflow is generated from the lower side in the vertical direction toward the lower space 42a in the slow cooling zone 420. Since this airflow rises along the sheet glass G and the sheet glass G is cooled by the airflow, it is preferable that there are

heat insulating members

40a, 40b,. For example, as shown in FIG. 2, the heat insulating member 40a forms a lower space 42a and a slow cooling space 42b, and the heat insulating member 40b forms a slow cooling space 42b and a slow cooling space 42c. The

heat insulating members

40a, 40b,..., 40h suppress heat transfer between the upper and lower spaces. For example, the heat insulating member 40a suppresses heat transfer and rising airflow between the lower space 42a and the slow cooling space 42b, and the heat insulating member 40b transfers heat and rise between the slow cooling space 42b and the slow cooling space 42c. Suppress airflow.

The plurality of

feed rollers

50a, 50b,..., 50h are arranged on both sides in the thickness direction of the sheet glass G at a predetermined interval in the vertical direction in the slow cooling zone 420. The

feeding rollers

50a, 50b,..., 50g are disposed in the

slow cooling spaces

42b, 42c,..., 42h, respectively, and convey the sheet glass G downward.

The

temperature control units

60a, 60b,..., 60h are composed of, for example, a sheathed heater, a cartridge heater, a ceramic heater, a temperature sensor, and the like that generate heat by resistance heating, dielectric heating, and microwave heating. 42h and the

slow cooling spaces

42b, 42c,..., 42h are arranged along the width direction of the sheet glass G, and the ambient temperature of the lower space 42a and the

slow cooling spaces

42b, 42c,. Control. Further, the

temperature control units

60a, 60b,..., 60h form a predetermined temperature distribution (hereinafter referred to as “temperature profile”) designed to prevent warping and distortion of the sheet glass G. The ambient temperature of the lower space 42a and the

slow cooling spaces

42b, 42c,. The

temperature control units

60a, 60b,..., 60h are collectively referred to as the temperature control unit 60. The upstream side refers to the side opposite to the conveying direction of the sheet glass G, and in this embodiment refers to the side of the molded body 10 when viewed from the slow cooling zone 420.

The detection device 70 is a device that measures the thickness of the glass plate, and includes, for example, an optical sensor, and measures the thickness of the sheet glass conveyed from the slow cooling zone for each predetermined width (for example, 1 mm width). The detection device 70 detects a portion (a convex portion or a concave portion) that is thicker or thinner than a reference value in the measured glass plate thickness, and sets this position as a position where a thickness deviation occurs. The temperature distribution in the width direction of the glass sheet or molten glass is adjusted by moving the shielding member 80 close or away according to the width and extent of the thickness deviation (height of the convex portion or depth of the concave portion).
In the adjustment of the temperature distribution of the thin plate portion, the heat from the heater is shielded by bringing the shielding member 80 close to the thin plate portion. As a result, the viscosity of the portion where the plate thickness is thin rises locally, and the glass flow is suppressed when the glass is pulled in the width direction.
In adjusting the temperature distribution of the thick plate portion, the shield member 80 is placed close to the portion adjacent to the thick plate portion to block the heat from the heater. Thereby, the viscosity of the part adjacent to the part with thick plate thickness rises, the flow of glass is suppressed, and the glass with the thick plate part flows on both sides, so that thickness deviation can be suppressed.
By repeating the adjustment of the temperature distribution described above, the thickness deviation for each predetermined interval in the glass width direction is adjusted to be a predetermined value or less.
Regarding the thickness deviation, the maximum glass plate thickness (t _max ) and the minimum glass plate are measured at predetermined intervals (for example, 20 mm, 100 mm, 300 mm) in the glass width direction from the measured value of the glass plate thickness using the detection device. The thickness (t _max ) can be detected, and the thickness deviation (t _max −t _max ), which is the difference between them, can be calculated. That is, the maximum glass plate thickness (t _max ) and the minimum glass plate thickness (t _max ) are detected from data at a predetermined interval, and the thickness deviation (t _max −t _max ) that is the difference between these is calculated. Thereby, a thickness deviation (t _max −t _max ) at every predetermined interval can be obtained.

Adjustment of the temperature distribution in the width direction orthogonal to the conveying direction of the molten glass MG or the sheet glass G is performed by adjusting the maximum glass plate thickness (t _max ) for every 20 mm in the glass width direction of the sheet glass obtained in the cooling step, and the minimum glass plate. the thickness deviation in thickness _(t max _{-t min)} between _{(t min)} is, so that each becomes 15μm or less, it is preferable to adjust. Further, the thickness deviation (t _max −t _min ) between the maximum glass plate thickness (t _max ) and the minimum glass plate thickness (t _min ) every 100 mm in the glass width direction is adjusted to be 20 μm or less, respectively. It is preferable to do. Further, the thickness deviation (t _max −t _min ) between the maximum glass plate thickness (t _max ) and the minimum glass plate thickness (t _min ) every 300 mm in the glass width direction is adjusted to be 25 μm. It is preferable. Furthermore, it is preferable to adjust the difference (t _max −t _min ) between the maximum glass plate thickness (t _max ) in the glass width direction and the minimum glass plate thickness (t _min ) to be 25 μm or less.

The shielding member 80 is not particularly limited as long as it is a rod-like member that shields the heat of the furnace wall 412, but the material of the shielding member 80 is preferably, for example, ceramic made of aluminum or silica. When the sheet glass G is to be shielded, the shielding member 80 is provided on both sides of the surface of the sheet glass G so as to sandwich the sheet glass G. Further, the shielding member 80 is provided on the side of the surface where the molten glass MG faces the upper space 410 when the molten glass MG flowing down on both side surfaces of the molded body 10 is to be shielded.
The shielding member 80 extends through the furnace wall 412 from the outer space of the furnace wall 412 into the upper space 410. A plurality of shielding members 80 that are rod-like members are continuously arranged so as to be aligned in a row in the width direction of the sheet glass G or the molten glass MG. Each of the shielding members 80 is configured to be able to advance and retract with respect to the surface of the sheet glass G or the molten glass MG. The length of one shielding member 80 along the width direction of the sheet glass G is, for example, 8 to 12 mm.
For example, the shielding member 80 shields the heat so that the sheet glass G and the molten glass MG are not heated by receiving the radiant heat of the heater 414 or the heat of the gas in the upper space 410. It is configured. That is, the shielding member 80 is placed on the surface of the sheet glass G or the molten glass MG so that the sheet glass G or the molten glass MG does not receive heat from the upper space 410 in a part of the width direction of the sheet glass G or the molten glass MG. Move closer. Thus, when the shielding member 80 partially shields heat, the temperature distribution in the width direction of the sheet glass G or the molten glass MG can be adjusted.
As described above, since the inspection device 70 can specify the position in the width direction of the sheet glass G of the concave portion or the convex portion where the thickness deviation has occurred, a plurality of shielding members are based on the position in the width direction. By bringing the rod-shaped shielding member 80 selected from 80 close to the surface of the sheet glass G or the molten glass MG, the temperature distribution in the width direction can be adjusted.

Specifically, when detecting the thickness deviation in which the plate thickness is locally reduced, the detection device 70 specifies the position in the width direction of the sheet glass G or the molten glass MG in which the plate thickness is reduced. The shielding member 80 is advanced using a drive mechanism (not shown) so that the rod-shaped shielding member 80 is brought close to the corresponding position in the width direction of the sheet glass G or the molten glass MG corresponding to this position. FIG. 5 is a diagram illustrating an example of adjusting the temperature distribution of the sheet glass G using a shielding member. FIG. 5 is a view as seen from the upstream side of the sheet glass G in the conveying direction. The example shown in FIG. 5 is an example in which, at a position A in the width direction, the plate thickness is locally thinned along the width direction, a concave portion is generated, and a plate thickness deviation to be suppressed occurs. At this time, the rod-shaped member 80a corresponding to the position A among the plurality of shielding members 80 is brought closer to the surface of the sheet glass G from both sides of the sheet glass G. Thereby, in the position A, since the heat from the upper space 410 is interrupted, the temperature at the position A is locally decreased, and the viscosity of the glass at the position A is increased. Therefore, when the molten glass MG leaves the formed body 10, the sheet glass G contracts in the width direction due to surface tension, and when the sheet glass G is pulled in the width direction, the heat is not blocked by the shielding member 80 a at the position A. It can be suppressed that the sheet thickness of the sheet glass G at the position A is locally reduced due to the locally increased viscosity of the glass. That is, the plate thickness deviation can be suppressed. In the example shown in FIG. 5, the sheet glass G is a target for adjusting the temperature distribution, but it is also preferable that the molten glass MG flowing through the molded body 10 is a target for adjusting the temperature distribution.

FIG. 6 is a diagram for explaining another example of adjusting the temperature distribution of the sheet glass G using the shielding member 80. FIG. 6 is a view as seen from the upstream side in the conveyance direction of the sheet glass G. The example shown in FIG. 6 is an example in which, at a position B in the width direction, the plate thickness locally increases along the width direction, a convex portion is generated, and a plate thickness deviation to be suppressed is generated. At this time, at the positions on both sides of the plurality of shielding members 80 so that the sheet glass G does not receive the heat of the upper space 410 at the positions on both sides of the position B that is the position where the thickness deviation is generated in the width direction. The shielding

members

80b and 80c are brought close to the surface of the sheet glass G. Thereby, on both sides of the position B, the heat from the upper space 410 is cut off, so that the temperature at the positions on both sides of the position B is locally decreased, and the viscosity of the glass is increased. Therefore, when the molten glass MG leaves the molded body 10 and the sheet glass G contracts in the width direction due to surface tension, and the sheet glass G is pulled in the width direction, the shielding

members

80b and 80c are positioned at both sides of the position B. Since the glass flow is suppressed by the locally increased viscosity of the glass as compared with the case where the heat is not shut off at the position B, the glass at the position B is easy to flow on both sides, so that the thickness of the sheet glass G at the position B is locally Can be suppressed. That is, the plate thickness deviation can be suppressed. In the example shown in FIG. 6, the sheet glass G is a target for adjusting the temperature distribution, but it is also preferable that the molten glass MG flowing through the molded body 10 is a target for adjusting the temperature distribution.

5 and 6, the shielding member 80a and the shielding

members

80b and 80c are brought close to the surface of the sheet glass G at positions A and B on both sides. The distance between 80a and the tips of the shielding

members

80b and 80c is preferably set in the range of 1 mm to 15 mm. In particular, the shielding member 80a or the shielding

members

80b and 80c and the sheet glass G depending on the degree of thickness deviation at the positions A and B, for example, the depth or height of the unevenness of the sheet glass G (thickness degree). It is preferable that the separation distance from the surface is adjusted. For example, it is preferable to decrease the separation distance as the degree of the plate thickness deviation increases. When the degree of thickness deviation is large, the temperature distribution in the width direction also fluctuates greatly. Therefore, in order to make the sheet glass G difficult to receive heat from the upper space 410, in order to increase the degree of blocking, the separation distance is made smaller. It is preferable to do.
In the examples shown in FIGS. 5 and 6, only the shielding member 80a and the shielding

members

80b and 80c are brought close to the surface of the sheet glass G at the positions on both sides of the position A and the position B, but the shielding member 80a, the shielding member 80b, The shielding member 80 adjacent to the shielding member 80c may be close to the surface of the sheet glass G, although not as much as the shielding member 80a and the shielding

members

80b and 80c.

In the present embodiment, the molten glass MG or the sheet glass G is performed in a region at a temperature equal to or higher than the softening point (the glass temperature when the glass viscosity corresponds to 10 ^7.6 poise). That is, the adjustment of the temperature distribution of the molten glass MG or the sheet glass G performed using the shielding member 80 is performed when the viscosity of the molten glass MG or the sheet glass G is 10 ^7.6 poise or less. For example, in the region of the viscosity of the glass is ¹⁰ 4.3 ^~ ¹⁰ 7.5 poise, to adjust the temperature distribution of the molten glass MG or sheet glass G by using the shielding member 80, reducing the thickness deviation efficiently It is preferable because of More preferably, the glass viscosity is in the range of 10 ^4.3 to 10 ^5.5 poise. In addition, it is preferable to adjust the temperature distribution using the shielding member 80 on the lower end 11 of the molded body 10 or on the upstream side in the conveying direction from the viewpoint that the thickness deviation can be efficiently reduced. By changing the temperature distribution locally in the viscosity region, the occurrence of thickness deviation can be effectively suppressed.

In the present embodiment, the position in the transport direction of the shielding member 80 that is close to the surface of the molten glass MG or the sheet glass G according to the widthwise dimension of the concave portion or the convex portion generated in the molten glass MG or the sheet glass G is determined. It is preferable to adjust. When a concave portion or a convex portion is generated in the molten glass MG or the sheet glass G, the temperature distribution can be adjusted from the lower end 11 of the molded body 10 to a position separated by 50 mm downstream or upstream in the transport direction. preferable. Further, it is more preferable to adjust the temperature distribution from the lower end 11 of the molded body 10 to a position 20 mm away from the lower end 11 on the downstream side or the upstream side in the transport direction. More preferably, the temperature distribution is adjusted at the height position (position in the transport direction) of the lower end 11 of the molded body 10. The position in the conveying direction where temperature adjustment is performed to suppress the plate thickness deviation and the separation distance at which the shielding member 80 is brought close to the surface of the sheet glass G or the molten glass MG are the extent of the concave portion or convex portion (the degree of concave and convex portions). The position is determined in advance according to the width, and the position of the conveyance direction in which the temperature adjustment is performed and the separation distance can be set according to the detected degree of the recess or protrusion (degree of unevenness) and the width.

In the present embodiment, the molding furnace chamber partitions (separates) the upper space 410 and the lower space 42a by the partition plate 20, and allows the sheet glass G to enter the lower space 42a through the slit holes between the partition plates 20. Cool down.
At this time, the shielding member 80 is preferably supported by the partition plate 20. Since the atmospheric temperature of the upper space 410 is extremely high, the rod-shaped shielding member 80 is thin and easy to bend due to its own weight. Therefore, the partition plate 20 supports the shielding member 80 from below so that the shielding member 80 is not deformed, and the temperature distribution can be adjusted at a predetermined position in the conveying direction of the sheet glass G or the molten glass MG. it can. If the position in the transport direction for adjusting the temperature distribution slightly deviates from the target position due to thermal deformation of the shielding member 80, the viscosity of the glass whose temperature distribution is to be adjusted tends to be different, so the thickness deviation can be accurately suppressed. Is difficult.
Depending on the width of the concave portion or convex portion generated in the molten glass MG or the sheet glass G, the temperature adjustment position in the transport direction differs. For this reason, when changing the temperature adjustment position, for example, by changing the thickness of the partition plate 20, the position of the shielding member 80 supported by the partition plate 20 in the transport direction is changed, thereby adjusting the temperature distribution. It is preferable to adjust the position in the transport direction to be attempted.
Moreover, it is also preferable that the shielding member 80 is provided so as to be sandwiched between the partition plates 20 by using two partition plates 20.
The furnace wall 412 is filled with glass wool made of glass fiber and the opening is closed. The partition plate 20 and the shielding plate 80 are directed toward the molten glass MG or the sheet glass G in this portion. It is configured so that it can be inserted. Therefore, when the position of the shielding member 80 in the conveyance direction is positioned upstream in the conveyance direction, the position of the shielding plate 80 can be adjusted by increasing the thickness of the partition plate 20.

As described above, in the present embodiment, the molten glass MG or the sheet glass G receives heat from the upper space 410 in the width direction orthogonal to the conveying direction of the molten glass MG or the sheet glass G flowing down from the molded body 10. By partially blocking with the shielding member 80, the temperature distribution in the width direction of the molten glass MG or the sheet glass G can be adjusted, so that it is possible to suppress a thickness deviation that is likely to occur in the conveying direction of the glass plate. .

As mentioned above, although the manufacturing method of the glass plate of this invention and the glass plate manufacturing apparatus were 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, various improvement and a change are carried out. Of course.

DESCRIPTION OF SYMBOLS 10 Molded body 11 Lower end 12 Groove 13a Side surface 13b Inclined surface 14 Glass supply pipe 20 Partition plate 30 Cooling roller 40a-40h Heat insulation member 42a Lower space 42b-42h Slow cooling space
50a to 50h Feed rollers 60a to 60h Temperature control unit 70

Detection device

80, 80a, 80b, 80c Shield member 100 Glass plate manufacturing device 200 Melting tank 300 Clarification tank 400 Molding apparatus 410 Upper space 412 Furnace wall 414 Heater 420 Slow cooling zone

Claims

A method of manufacturing a glass substrate,
After the molten glass overflowed from the upper part of the molded body in the upper space of the heated molding furnace chamber is caused to flow down along both side surfaces of the molded body, the molten glass is joined at the lower end of the molded body. A molding process for making the sheet glass to be conveyed;
A cooling step for cooling the sheet glass;
In the width direction orthogonal to the conveying direction of the molten glass or the sheet glass, the molten glass or the sheet glass is partially blocked by the shielding member from receiving heat from the upper space, so that the molten glass or An adjustment step of adjusting the temperature distribution in the width direction of the sheet glass.
In the adjusting step, the molten glass or the sheet glass is partially blocked by the shielding member from receiving heat from the upper space, so that every 20 mm in the glass width direction of the sheet glass obtained in the cooling step. The temperature distribution in the width direction of the molten glass or the sheet glass is adjusted so that the difference t max −t min between the maximum glass plate thickness t max and the minimum glass plate thickness t min is 15 μm or less, respectively. The manufacturing method of the glass substrate of Claim 1 adjusted.
The difference t max −t min between the maximum glass plate thickness t max and the minimum glass plate thickness t min obtained every 100 mm in the glass width direction of the sheet glass obtained in the cooling step is 20 μm or less, respectively. The method for producing a glass substrate according to claim 1, wherein in the adjusting step, the temperature distribution in the width direction of the molten glass or the sheet glass is adjusted.
When a concave portion is generated in the molten glass or the sheet glass and a thickness deviation occurs, the molten glass or the sheet glass does not receive heat in the upper space at the generation position in the width direction of the concave portion in the adjustment step. The method of manufacturing a glass substrate according to claim 1, wherein the temperature distribution is adjusted by bringing the shielding member closer to the generation position.
When a convex part occurs in the molten glass or the sheet glass and a thickness deviation occurs, in the adjustment step, the molten glass or the sheet glass is positioned at both sides sandwiching the generation position in the width direction of the convex part. The method of manufacturing a glass substrate according to any one of claims 1 to 4, wherein the temperature distribution is adjusted by bringing the shielding member close to the positions on both sides so as not to receive heat of the upper space.
The method for manufacturing a glass substrate according to claim 4 or 5, wherein a separation distance between the shielding member and the surface of the sheet glass is adjusted according to a degree of the thickness deviation.
The method for producing a glass substrate according to any one of claims 1 to 6, wherein the adjusting step is performed when the viscosity of the molten glass or the sheet glass is 10 7.6 poise or less.
The adjustment process is performed according to any one of claims 1 to 7, wherein the adjusting step is performed from the lower end of the molded body to a position spaced 50 mm away from the molten glass or the sheet glass in the conveyance direction downstream side or upstream side. The manufacturing method of the glass substrate of description.
The cooling step includes cooling both end portions of the sheet glass with a cooling roller in order to prevent the sheet glass from shrinking in the width direction of the sheet glass;
The upper space is located on the upstream side in the conveyance direction of the sheet glass with respect to the partition plate that partitions from the lower space in which the cooling roller is provided,
The glass substrate manufacturing method according to any one of claims 1 to 8, wherein the shielding member is provided in the upper space.
The molding furnace chamber allows the sheet glass to enter the lower space through a slit hole between the partition plates,
The method for manufacturing a glass substrate according to claim 9, wherein the shielding member is supported by the partition plate.
The method for manufacturing a glass substrate according to claim 10, wherein the position in the transport direction for adjusting the temperature distribution is adjusted by using the shielding member by changing the thickness or height of the partition plate.
An apparatus for manufacturing a glass substrate,
A molding furnace chamber;
A molded body that is provided in the upper space of the molding furnace chamber, overflows the molten glass and flows down along both side surfaces, and then forms a sheet glass that is conveyed by joining the molten glass at the lower end, and
A heat source for heating the walls of the upper space and the atmosphere in the upper space;
The molten glass or the sheet glass is partially blocked from receiving heat from the upper space in the width direction perpendicular to the conveying direction of the molten glass or the sheet glass. And a shielding member that adjusts the temperature distribution in the width direction of the glass substrate.