JP6767866B2 - Glass substrate manufacturing method and glass substrate manufacturing equipment - Google Patents

Description

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 manufacturing a glass plate. In the down draw method, the molten glass overflowing from the molded body is split and flows down along the side surface of the molded body. The molten glass that splits and flows down merges at the lower end of the molded body and is molded 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 changes from a viscous region to a viscoelastic region and then to an elastic region.

The molten glass flowing down along the side surface 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, the glass plate has a plate thickness deviation or unevenness. In Patent Document 1, a cooling unit provided between the molded body and the tension roller below the molded body, in the vicinity of the edge portion in the width direction of the glass plate, and separated from the glass plate is used. A method of adjusting the temperature of the edge portion to suppress the shrinkage of the glass plate is disclosed. After that, the glass plate whose shrinkage is suppressed passes through the slow cooling space and is formed. In this slow cooling space, the ambient temperature is controlled to have a desired temperature profile (temperature distribution that does not cause distortion in the glass plate), and the plate thickness deviation of the glass plate is suppressed. On the other hand, in recent years, in the glass substrate for a liquid crystal display device, the specifications (quality) required for the plate thickness deviation of the glass plate have become strict.

The plate thickness deviation is a thickness deviation that occurs in the width direction of the glass plate, and is continuously generated in the transport direction of the glass plate, and the generation position in the width direction of the glass plate is often constant. In order to meet the recent strict requirements for plate thickness deviation, it is not enough to perform thermal control in a slow cooling space.

Japanese Patent Application Laid-Open No. 5-124827

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 generated along the transport direction of the glass plate.

One aspect of the present invention is a method for manufacturing a glass substrate. The manufacturing method is
The molten glass overflowing from the upper part of the molded body in the upper space of the heated molding furnace chamber is allowed to flow down along both side surfaces of the molded body, and then the molten glass is merged at the lower end of the molded body. The molding process to make the sheet glass to be transported and
A cooling step for cooling the sheet glass and
The molten glass or the sheet glass is formed by partially blocking the molten glass or the sheet glass from receiving heat from the upper space in a width direction orthogonal to the transport direction of the molten glass or the sheet glass. The sheet glass is provided with an adjusting step for adjusting the temperature distribution in the width direction of the sheet glass.
When a convex portion is generated on the molten glass or the sheet glass and a thickness deviation occurs, in the adjusting step, the molten glass or the molten glass or at positions on both sides in the width direction sandwiching the generation position of the convex portion in the width direction. The temperature distribution is adjusted by bringing the shielding members close to each other at the positions on both sides so that the sheet glass does not receive the heat of the upper space.

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

At this time, when a recess 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 heats the upper space at the position where the recess is generated in the width direction. It is preferable to adjust the temperature distribution by bringing the shielding member close to the position where the recess is generated so as not to receive the heat.

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 adjustment step, the molten glass or the viscosity of the sheet glass is made when in the following 10 ^7.6 poise, it is preferable.

It is preferable that the adjustment step is performed from the lower end of the molded product to a position 50 mm away from the molten glass or the sheet glass on the downstream side or the upstream side in the transport direction.

The cooling step comprises cooling both ends of the sheet glass with cooling rollers 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 transport direction of the sheet glass with respect to the partition plate that partitions the lower space where the cooling roller is provided.
It is preferable that the shielding member is provided in the upper space.

In the molding furnace chamber, the sheet glass is allowed to enter the lower space through a slit hole between the partition plates.
It is preferable that the shielding member is supported by the partition plate.

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

Further, one aspect of the present invention is a glass substrate manufacturing apparatus. The manufacturing equipment
Molding furnace room and
A molded body provided in the upper space of the molding furnace chamber, which overflows the molten glass and causes it to flow down along both side surfaces, and then merges the molten glass at the lower end to form a sheet glass to be conveyed.
A heat source that heats the wall of the upper space and the atmosphere in the upper space,
The molten glass or the sheet glass is formed by partially blocking the molten glass or the sheet glass from receiving heat from the upper space in a width direction orthogonal to the conveying direction of the molten glass or the sheet glass. A shielding member for adjusting the temperature distribution in the width direction of the above.
When a convex portion is generated on the molten glass or the sheet glass and a thickness deviation occurs, the molten glass or the sheet glass is said to be at positions on both sides of the width direction sandwiching the generation position of the convex portion in the width direction. The shielding members are brought close to each other at the positions on both sides so as not to receive the heat of the upper space.

According to the above-mentioned glass plate manufacturing method and glass plate manufacturing apparatus, the width direction is orthogonal to the transport direction of the molten glass flowing on the side surface of the molded body or the sheet glass formed with the molten glass separated 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 sectional drawing schematic block of an example of the molding apparatus of this embodiment. It is a side schematic block diagram of an example of the molding apparatus of this embodiment. It is a figure which expands and explains an example of the upper space of the molding furnace chamber of this embodiment in which a molded body is arranged. 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 another example of adjusting the temperature distribution of the sheet glass using the shielding member of this embodiment.

Hereinafter, the glass plate manufacturing method and the glass plate manufacturing apparatus according to the present embodiment will be described. FIG. 1 is a schematic configuration diagram of an example of a glass plate manufacturing apparatus according to the present embodiment.
As shown in FIG. 1, the glass plate manufacturing apparatus 100 includes a melting tank 200, a clarification tank 300, and a molding apparatus 400. In the melting tank 200, the raw material of glass is melted to produce molten glass. The molten glass produced in the melting tank 200 is sent to the clarification tank 300. In the clarification tank 300, air 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 molding apparatus 400, the sheet glass G is continuously molded from the molten glass by, for example, an overflow down draw method. After that, the molded 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 reinforced glass such as a cover glass or a magnetic disk, and a roll shape. It is used as a glass substrate on which electronic devices such as a glass substrate and a semiconductor wafer that are wound around the glass are laminated.

Next, the detailed configuration of the molding apparatus 400 will be described. FIG. 2 is a schematic cross-sectional configuration diagram of an example of a molding apparatus, and FIG. 3 is a side schematic configuration diagram of an example of a molding apparatus. FIG. 4 is an enlarged view of an example of the upper space of the molding furnace chamber in which the molded body is arranged.
In the molding apparatus 400, a molding step of making a sheet glass by an overflow down draw method, a cooling step of cooling the molded sheet glass, and a temperature in a width direction orthogonal to the transport direction of the molten glass or the sheet glass when making the sheet glass. An adjustment step of adjusting the distribution is performed.
As shown in FIGS. 2 to 4, the molding apparatus 400 includes a molded 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. Further, the molding apparatus 400 is provided in the upper space 410 of the molding furnace chamber, which is the space above the partition plate 20, the lower space 42a of the molding furnace chamber, which is the space directly below the partition plate 20, and the space below the lower space 42a. It has a slow cooling zone 420. The slow cooling zone 420 has a plurality of slow cooling spaces 42b, 42c, ..., 42h. The lower space 42a, the slow cooling space 42b, the slow cooling space 42c, ..., The slow cooling space 42h are laminated in this order from the upper side to the lower side in the vertical direction. The upper space 410, the lower space 42a, and the slow cooling zone 420 are surrounded by a fireproof material and / or a heat insulating material building (not shown), and in the lower space 42a, the slow cooling zone 420, a cooling step of the sheet glass G is performed. The temperature control unit 60a and the like control the sheet glass G to a temperature suitable for molding and cooling.

As shown in FIG. 4, the upper space 410 is separated from the external space by a furnace wall 412 made of a member which is 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 in the height direction of the molded body 10 (vertical direction on the paper surface in FIG. 4). A plurality of heaters 414 are provided.

As shown in FIG. 2 or 4, the molded body 10 is a member having a substantially wedge-shaped cross-sectional shape. The molded body 10 is arranged in the upper space 410 so that the substantially wedge-shaped lower end 11 is at the lowermost end. 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. A glass supply pipe 14 is provided at one end of the groove 12. The groove 12 is formed so as to gradually become shallower as the glass supply pipe 14 is provided from one end to the other end. Guides are attached to both ends of the molded body 10 in the longitudinal direction to prevent the molten glass MG from protruding from the side wall. The molten glass MG overflowing from the groove 12 flows through 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 means a direction orthogonal to the conveying direction among the in-plane directions 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, a portion having a thickness larger than the plate thickness at the center in the width direction of the sheet glass G is formed. Further, the central region, which is a region in the width direction sandwiched between the end portions on both sides of the sheet glass G, is thinner than the end portions and has a small amount of heat retained. Therefore, the amount of heat retained is likely to change due to temperature unevenness and the like, and warpage and distortion are likely to occur. Therefore, it is necessary to strictly control the cooling amount in the central region. In the present embodiment, the plate thickness deviation including the irregularities of the sheet glass G is suppressed by increasing the adjustment accuracy of the temperature and viscosity of the molten glass MG and the sheet glass G fused at the lower end 11 of the molded body 10. .. In the following, the glass before being fused at the lower end 11 of the molded body 10 is referred to as molten glass MG, and the glass after being fused at the lower end 11 is referred to as sheet glass G. In thin glass, the occurrence of plate thickness deviation is not preferable, and in particular, in the glass plate used for the glass substrate for display, the occurrence of partial plate thickness deviation has a great adverse effect on the display accuracy of the display, and is not preferable.

The partition plate 20 is a plate-shaped heat insulating material arranged 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 of the partition plate 20 in the height direction is located below the position of the lower end 11 of the molded body 10 in the height direction. As shown in FIGS. 2 and 4, the partition plates 20 are arranged on both sides of the sheet glass G in the thickness direction. 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 partition plate 20 which is a heat insulating material separates the upper space 410 and the lower space 42a so that the upper space 410 and the lower space 42a each have a temperature so that the two spaces do not affect each other with respect to the temperature in the space. This is for control. Further, the partition plate 20 is arranged so that the distance between the sheet glass G and the partition plate 20 is adjusted in advance so as to suppress the volumetric flow rate of the updraft entering the upper space 410 from the slow cooling zone 420.

The cooling roller 30 is arranged in the vicinity of the partition plate 20 in the lower space 42a. Further, the cooling rollers 30 are arranged on both sides of the sheet glass G in the thickness direction, sandwich the sheet glass G in the thickness direction, and cool the end portion of the sheet glass G while transporting the sheet glass G downward. Carry. The molten glass MG that has flowed 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 a portion adjacent to the side of the central region with respect to both end portions of the sheet glass G that contracts in the width direction, thereby preventing the sheet glass G from contracting in the width direction, and the sheet glass. Cool G. As a result, shrinkage of the sheet glass G in the width direction is suppressed, and distortion, plate thickness deviation, and unevenness that occur in the sheet glass G are suppressed. However, if the viscosity of the sheet glass G at the lower end 11 of the molded body 10 is high and the shrinkage rate of the sheet glass G is large, the cooling roller 30 may not be able to suppress distortion, plate thickness deviation, and unevenness. Therefore, in the present embodiment, by adjusting the heat management at the lower end 11 of the molded body 10 with the shielding member 80, the accuracy of the heat management can be improved and the plate thickness deviation can be suppressed. That is, the step of cooling the sheet glass includes cooling both end portions of the sheet glass G with a 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 of the sheet glass G in the transport direction with respect to the partition plate 20 that partitions the lower space 42a where the cooling roller 30 is provided, and the shielding member 80 is provided in the upper space 410.

In the slow cooling zone 420, the heat insulating members 40a, 40b, ..., 40h form a plurality of slow cooling spaces 42b, 42c, in the slow cooling zone 420 with respect to the transport direction (vertically downward) of the sheet glass G.・ It is divided into 42h, and the heat transfer of each divided slow cooling space is suppressed. Further, the heat insulating members 40a, 40b, ..., 40h are plate-shaped members arranged below the cooling roller 30 and on both sides in the thickness direction of the sheet glass G, and the sheet glass G is conveyed in the transport direction. It has a slit-shaped space to guide. As described above, 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 sheet glass G is carried out to the slow cooling zone 420. There is a slit-shaped space, and there are some minute gaps in the heat insulating material building and the like. Therefore, due to the chimney effect, an updraft from the lower part in the vertical direction toward the lower space 42a is generated in the slow cooling zone 420. Since this air flow rises along the sheet glass G and the sheet glass G is cooled by the air flow, it is preferable that there are heat insulating members 40a, 40b, ..., 40h that suppress the air flow. 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 updraft between the lower space 42a and the slow cooling space 42b, and the heat insulating member 40b suppresses heat transfer and rise between the slow cooling space 42b and the slow cooling space 42c. Suppress airflow.

A plurality of feed rollers 50a, 50b, ..., 50h are arranged on both sides of the sheet glass G in the thickness direction at predetermined intervals in the vertical direction in the slow cooling zone 420. The feed rollers 50a, 50b, ..., 50g are arranged 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, etc. that generate heat by resistance heating, dielectric heating, and microwave heating, and each of them has a lower space. The atmosphere temperature of the lower space 42a and the slow cooling space 42b, 42c, ..., 42h is measured along the width direction of the sheet glass G in the slow cooling space 42b, 42c, ..., 42h. Control. Further, the temperature control units 60a, 60b, ..., 60h form a predetermined temperature distribution (hereinafter referred to as "temperature profile") designed so that the sheet glass G does not warp or distort. The ambient temperature of the lower space 42a and the slow cooling spaces 42b, 42c, ..., 42h is controlled. When 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 transport direction of the sheet glass G, and in the present embodiment, refers to the side of the molded body 10 as viewed from the slow cooling zone 420.

The detection device 70 is a device for measuring the glass plate thickness, for example, which is composed of an optical sensor and measures the plate 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 (convex or concave portion) of the measured glass plate thickness that is thicker or thinner than the reference value, and sets this position as the position where the thickness deviation occurs. Depending on the width and degree of the thickness deviation (height of the convex portion or depth of the concave portion), the shielding member 80 is brought close to or separated from each other to adjust the temperature distribution in the width direction of the glass sheet or the molten glass.
In adjusting the temperature distribution of the thin plate portion, the shielding member 80 is brought close to the thin plate portion to shield the heat from the heater. As a result, the viscosity of the thin portion is locally increased, and the flow of the glass is suppressed when the glass is pulled in the width direction.
In adjusting the temperature distribution of the thick plate portion, the shielding member 80 is brought close to the portion adjacent to the thick plate portion to block heat from the heater. As a result, the viscosity of the portion adjacent to the thick portion increases and the flow of the glass is suppressed, and the glass of the thick portion flows on both sides, so that the thickness deviation can be suppressed.
By repeating the above adjustment of the temperature distribution, the thickness deviation at each predetermined interval in the glass width direction is adjusted to be equal to or less than the predetermined value.
Regarding the thickness deviation, the maximum glass plate thickness (t _max ) and the minimum glass plate are obtained 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 above detection device. It is possible to detect the thickness (t _max ) and calculate the thickness deviation (t _max −t _max ) which is the difference between them. That is, the maximum glass plate thickness (t _max ) and the minimum glass plate thickness (t _max ) are detected from the data at predetermined intervals, and the thickness deviation (t _max −t _max ), which is the difference between them, is calculated. As a result, the thickness deviation (t _max −t _max ) at predetermined intervals can be obtained.

The temperature distribution in the width direction orthogonal to the transport direction of the molten glass MG or the sheet glass G is adjusted by adjusting the maximum glass plate thickness (t _max ) of the sheet glass obtained in the cooling step for each 20 mm in the glass width direction 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 ) in every 100 mm in the glass width direction is adjusted to be 20 μm or less. It is preferable to do so. Further, the thickness deviation (t _max −t _min ) between the maximum glass plate thickness (t _max ) and the minimum glass plate thickness (t _min ) in every 300 mm in the glass width direction is adjusted to be 25 μm, respectively. Is preferable. Further, 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-shaped member that shields the heat of the furnace wall 412, but the material of the shielding member 80 is preferably, for example, ceramics made from aluminum or silica. When the sheet glass G is to be shielded, the shielding members 80 are provided on both sides with respect to 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 targeted for shielding.
The shielding member 80 penetrates the furnace wall 412 and extends from the external space of the furnace wall 412 into the upper space 410. A plurality of shielding members 80, which are rod-shaped members, are continuously arranged so as to be arranged in a line 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 move forward and backward with respect to the surface of the sheet glass G or the molten glass MG. The length of the sheet glass G of one shielding member 80 along the width direction is, for example, 8 to 12 mm.
The shielding member 80 blocks 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 and the heat of the gas in the upper space 410, for example. 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 sheet glass G or the molten glass MG in the width direction. Get closer. In this way, the shielding member 80 partially blocks heat, so that the temperature distribution in the width direction of the sheet glass G or the molten glass MG can be adjusted.
As described above, the inspection device 70 can specify the position of the concave portion or the convex portion where the thickness deviation has occurred in the width direction of the sheet glass G, and therefore, the plurality of shielding members are based on the position in the width direction. The temperature distribution in the width direction can be adjusted by bringing the rod-shaped shielding member 80 selected from the 80s closer to the surface of the sheet glass G or the molten glass MG.

Specifically, when the detection device 70 detects a plate 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 whose plate thickness is reduced. The shielding member 80 is advanced by using a drive mechanism (not shown) so that the rod-shaped shielding member 80 approaches 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 the shielding member. FIG. 5 is a view seen from the upstream side in the transport direction of the sheet glass G. The example shown in FIG. 5 is an example in which the plate thickness is locally thinned along the width direction at the position A in the width direction, a recess is generated, and a plate thickness deviation to be suppressed occurs. At this time, among the plurality of shielding members 80, the rod-shaped member 80a corresponding to the position A is brought close to the surface of the sheet glass G from both sides of the sheet glass G. As a result, at position A, the heat from the upper space 410 is blocked, so that the temperature at position A decreases locally and the viscosity of the glass at position A increases. Therefore, when the molten glass MG separates from the molded body 10, 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 heat is not blocked by the shielding member 80a at the position A. In comparison, the locally increased viscosity of the glass can prevent the sheet glass G at position A from being locally thinned. That is, the plate thickness deviation can be suppressed. In the example shown in FIG. 5, the sheet glass G is the target of the temperature distribution adjustment, but it is also preferable that the molten glass MG flowing through the molded body 10 is the target of the temperature distribution adjustment.

FIG. 6 is a diagram illustrating another example of adjusting the temperature distribution of the sheet glass G using the shielding member 80. FIG. 6 is a view seen from the upstream side in the transport direction of the sheet glass G. The example shown in FIG. 6 is an example in which the plate thickness becomes locally thicker along the width direction at the position B in the width direction, a convex portion is generated, and a plate thickness deviation to be suppressed occurs. At this time, among the plurality of shielding members 80, at the positions on both sides of the position B, which is the position where the plate thickness deviation occurs in the width direction, the sheet glass G does not receive the heat of the upper space 410. The shielding members 80b and 80c are brought close to the surface of the sheet glass G. As a result, heat from the upper space 410 is blocked on both sides of the position B, so that the temperature at the positions on both sides of the position B is locally lowered and the viscosity of the glass is increased. Therefore, when the molten glass MG separates from the molded body 10, 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, 80c are held at both positions sandwiching the position B. While the glass flow is suppressed by the locally increased viscosity of the glass as compared with the case where the heat is not blocked by, the glass at the position B easily flows to both sides, so that the thickness of the sheet glass G at the position B is locally increased. It is possible to suppress the thickening. That is, the plate thickness deviation can be suppressed. In the example shown in FIG. 6, the sheet glass G is the target of the temperature distribution adjustment, but it is also preferable that the molten glass MG flowing through the molded body 10 is the target of the temperature distribution adjustment.

In the examples shown in FIGS. 5 and 6, the shielding members 80a and the shielding members 80b and 80c are brought close to the surface of the sheet glass G at both positions A and B, but the surface of the sheet glass G and the shielding member The separation distance between the 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, depending on the degree of plate thickness deviation at positions A and B, for example, the degree of unevenness or height of the sheet glass G (degree of thickness deviation), the shielding member 80a or the shielding members 80b, 80c and the sheet glass G It is preferable that the distance from the surface of the glass is adjusted. For example, it is preferable to reduce the separation distance as the degree of plate thickness deviation increases. When the degree of plate thickness deviation is large, the fluctuation of the temperature distribution in the width direction is also large, so that the separation distance is made smaller in order to increase the degree of blocking in order to make the sheet glass G less likely to receive heat from the upper space 410. It is preferable to do so.
Further, in the examples shown in FIGS. 5 and 6, only the shielding members 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 positions A and B, but the shielding members 80a and the shielding members 80b, The shielding member 80 adjacent to the shielding member 80c may be brought closer to the surface of the sheet glass G, though not as much as the shielding member 80a and the shielding members 80b, 80c.

In this embodiment, molten glass MG or sheet glass G has a softening point is carried out in one region of the (viscosity of the glass is the glass temperature at which corresponding to 10 ^7.6 poise) or higher. That is, the adjustment of the temperature distribution of the molten glass MG or sheet glass G carried out using the shielding member 80 is carried out when the viscosity of the molten glass MG or sheet glass G is below 10 ^7.6 poise. For example, in the region where the viscosity of the glass is 10 ^4.3 to ^7.5 poise, adjusting the temperature distribution of the molten glass MG or the sheet glass G using the shielding member 80 effectively reduces the plate thickness deviation. It is preferable because it can be used. More preferably, a region of the glass viscosity ¹⁰ 4.3 ^~10 5.5 poise. Further, it is preferable to adjust the temperature distribution by using the shielding member 80 at the lower end 11 of the molded body 10 or on the upstream side in the transport direction from the viewpoint that the plate thickness deviation can be efficiently reduced. By locally changing the temperature distribution in the above viscosity region, the occurrence of plate thickness deviation can be effectively suppressed.

Further, in the present embodiment, the position of the shielding member 80 brought closer to the surface of the molten glass MG or the sheet glass G in the transport direction is determined according to the width direction dimension of the concave portion or the convex portion generated in the molten glass MG or the sheet glass G. 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 50 mm away from the downstream side or the upstream side 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 transport direction in which the temperature is adjusted in order to suppress the plate thickness deviation and the separation distance for bringing the shielding member 80 close to the surface of the sheet glass G or the molten glass MG are the degree of the concave or convex portion (degree of unevenness). It is predetermined according to the width, and the position in the transport direction for adjusting the temperature and the separation distance can be set according to the detected degree (degree of unevenness) and width of the concave portion or convex portion.

In the present embodiment, in the molding furnace chamber, the upper space 410 and the lower space 42a are partitioned (separated) by the partition plate 20, and the sheet glass G is made to enter the lower space 42a through the slit hole between the partition plates 20 to enter the sheet glass G. To cool.
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 long and thin and easily bends 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, so that the temperature distribution can be adjusted at a predetermined position in the transport direction of the sheet glass G and the molten glass MG. it can. If the position in the transport direction for adjusting the temperature distribution deviates slightly from the target position due to thermal deformation of the shielding member 80, the viscosity of the glass for which the temperature distribution is to be adjusted tends to differ, so that the plate thickness deviation should be accurately suppressed. Is difficult.
The temperature adjustment position in the transport direction differs depending on the width of the concave portion or the convex portion generated in the molten glass MG or the sheet glass G. Therefore, 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 intended.
Further, it is also preferable that the shielding member 80 uses two partition plates 20 and is provided so as to be sandwiched between the partition plates 20.
Glass wool made of glass fiber is packed in the opening of the furnace wall 412 to close the opening, and 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 transport direction is positioned on the upstream side in the transport 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 transport 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 the plate thickness deviation that tends to occur in the transport direction of the glass plate can be suppressed. ..

Although the glass plate manufacturing method and the glass plate manufacturing apparatus of the present invention have been described in detail above, the present invention is not limited to the above embodiment, and various improvements and changes are made without departing from the gist of the present invention. Of course, you may.

10 Mold 11 Lower end 12 Groove 13a Side surface 13b Inclined surface 14 Glass supply pipe 20 Partition plate 30 Cooling roller 40a to 40h Insulation member 42a Lower space 42b to 42h Slow cooling space
50a to 50h Feed roller 60a to 60h Temperature control unit 70 Detection device 80, 80a, 80b, 80c Shielding member 100 Glass plate manufacturing device 200 Melting tank 300 Clarification tank 400 Molding device 410 Upper space 412 Furnace wall 414 Heater 420 Slow cooling zone

Claims (11)

It is a method of manufacturing a glass substrate.
The molten glass overflowing from the upper part of the molded body in the upper space of the heated molding furnace chamber is allowed to flow down along both side surfaces of the molded body, and then the molten glass is merged at the lower end of the molded body. The molding process to make the sheet glass to be transported and
A cooling step for cooling the sheet glass and
The molten glass or the sheet glass is formed by partially blocking the molten glass or the sheet glass from receiving heat from the upper space in a width direction orthogonal to the transport direction of the molten glass or the sheet glass. A step of adjusting the temperature distribution of the sheet glass in the width direction is provided .
When a convex portion is generated on the molten glass or the sheet glass and a thickness deviation occurs, in the adjusting step, the molten glass or the molten glass or at positions on both sides of the width direction sandwiching the generation position of the convex portion in the width direction. A method for manufacturing a glass substrate, characterized in that the shielding members are brought close to each other at positions on both sides to adjust the temperature distribution so that the sheet glass does not receive heat from the upper space . In the adjusting step, by partially blocking the molten glass or the sheet glass from receiving heat from the upper space with a shielding member, 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 obtained maximum glass plate thickness t _max and the minimum glass plate thickness t _min is 15 μm or less, respectively. The method for manufacturing a glass substrate according to claim 1, which is 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 set to 20 μm or less. The method for manufacturing a glass substrate according to claim 1 or 2, wherein in the adjusting step, the temperature distribution of the molten glass or the sheet glass in the width direction is adjusted. When a recess occurs 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 position where the recess is generated in the width direction in the adjustment step. The method for manufacturing a glass substrate according to any one of claims 1 to 3, wherein the shielding member is brought close to the position where the recess is generated to adjust the temperature distribution. The method for manufacturing a glass substrate according to any one of claims 1 to 4 , wherein 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 adjustment step, the viscosity of the molten glass or the sheet glass is made when in the following 10 ^7.6 poise, a manufacturing method of a glass substrate according to any one of claims 1-5. The adjustment step is performed from the lower end of the molded body to a position 50 mm away from the molten glass or the sheet glass in the downstream side or the upstream side in the transport direction, according to any one of claims 1 to 6. The method for manufacturing a glass substrate according to the description. The cooling step comprises cooling both ends of the sheet glass with a cooling roller 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 transport direction of the sheet glass with respect to the partition plate that separates the lower space from which the cooling roller is provided.
The method for manufacturing a glass substrate according to any one of claims 1 to 7 , wherein the shielding member is provided in the upper space. In the molding furnace chamber, the sheet glass is allowed to enter the lower space through a slit hole between the partition plates.
The method for manufacturing a glass substrate according to claim 8 , wherein the shielding member is supported by the partition plate. The method for manufacturing a glass substrate according to claim 9 , 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. It is a glass substrate manufacturing equipment
Molding furnace room and
A molded body provided in the upper space of the molding furnace chamber, which overflows the molten glass and causes it to flow down along both side surfaces, and then merges the molten glass at the lower end to form a sheet glass to be conveyed.
A heat source that heats the wall of the upper space and the atmosphere in the upper space,
The molten glass or the sheet glass is formed by partially blocking the molten glass or the sheet glass from receiving heat from the upper space in a width direction orthogonal to the conveying direction of the molten glass or the sheet glass. A shielding member that adjusts the temperature distribution in the width direction of the glass .
When a convex portion is generated on the molten glass or the sheet glass and a thickness deviation occurs, the molten glass or the sheet glass is said to be at positions on both sides of the width direction sandwiching the generation position of the convex portion in the width direction. so as not to receive heat in the upper space, a glass substrate manufacturing apparatus according to claim Rukoto closer to the shielding member at a position of the both sides.

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