KR101743375B1

KR101743375B1 - Method and apparatus for making glass sheet

Info

Publication number: KR101743375B1
Application number: KR1020157002182A
Authority: KR
Inventors: 신고 후지모토; 료 스즈키
Original assignee: 아반스트레이트 가부시키가이샤
Priority date: 2013-12-26
Filing date: 2014-12-26
Publication date: 2017-06-02
Also published as: KR20150101984A; JPWO2015099157A1; WO2015099157A1

Abstract

A method of manufacturing a glass substrate and a glass substrate manufacturing apparatus capable of controlling the flow rate of the molten glass even when the flow rate of the molten glass is large. Wherein the processing apparatus is heated by energizing the processing apparatus so that the temperature of the molten glass in the processing apparatus is in a range suitable for the processing when the molten glass is processed and the flow rate of the molten glass in the processing apparatus Is controlled by the amount of electric power at the time of energization so that the amount of electric power becomes equal to or more than a power amount capable of controlling the flow rate of the molten glass and the temperature of the molten glass becomes a temperature range in which the flow rate of the molten glass can be controlled , The amount of heat radiation from the processing apparatus to the outside is controlled.

Description

TECHNICAL FIELD [0001] The present invention relates to a method of manufacturing a glass substrate,

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

The glass substrate is generally manufactured through a process of forming a molten glass from a glass raw material and then molding the molten glass into a glass substrate. The above process includes a step of removing minute bubbles contained in the molten glass (hereinafter referred to as clarification). The refining is carried out by heating the body of the refining tube while passing the molten glass blended with the refining agent to the refining tube main body and removing the bubbles in the molten glass by the redox reaction of the refining agent. More specifically, the temperature of the molten glass that has been coarsely dissolved is further increased to function as a fining agent to float the bubbles, and then the temperature is lowered so that the relatively small bubbles that are not fully defoamed are absorbed into the molten glass . That is, the finishing includes a process of floating and degassing bubbles (hereinafter, also referred to as a degassing process or a defoaming process) and a process of absorbing small bubbles into a molten glass (hereinafter also referred to as an absorption process or an absorption process).

As a technique for heating the cleaning tube to heat the molten glass in the refining treatment, for example, a pair of flange-shaped electrodes are formed on the cleaning tube, and a voltage is applied to the pair of electrodes, (Patent Document 1).

Japanese Published Patent Publication No. 2011-513173

In this apparatus, the amount of heat applied to the molten glass in the purifying pipe can be adjusted by the amount of electricity supplied to the purifying pipe. Therefore, even if the flow rate of the molten glass passing through the purifying tube is increased, the temperature of the molten glass can be raised to the temperature required for the degassing treatment by increasing the amount of electricity to be supplied according to the flow rate.

There is a viscosity of the molten glass as one factor in determining the flow rate of the molten glass passing through the purifying tube. The viscosity of the molten glass is determined by the temperature of the molten glass, and the temperature of the molten glass is controlled by the amount of electricity flowing into the purifying tube. Therefore, the flow rate of the molten glass can be controlled by the amount of electric current flowing to the outlet of the purifying tube.

However, if the temperature in the low-temperature region of the cleaning tube is raised and the amount of heating in the subsequent process is reduced, the amount of electricity flowing to the cleaning tube outlet becomes small, making it impossible to control the flow rate of the molten glass. Further, if the flow rate of the molten glass is large, for example, even if the flow rate of the cleaning tube outlet is zero, the temperature of the molten glass can not be lowered, and the flow rate of the molten glass can not be controlled. If the flow rate of the molten glass can not be controlled, there is a concern that the molten glass overflows in the processing apparatus downstream of the purifying pipe. Further, since it is difficult to lower the temperature of the molten glass to a temperature required for the absorption treatment, there is a problem that the reboiler bubbles derived from nitrogen or sulfur oxide are increased as a result.

In order to avoid the above problem, it is necessary to lower the temperature of the molten glass in the purifying tube. However, if the molten glass temperature is lowered by lowering the amount of electricity to the purifying tube, have. In addition, it is difficult to raise the temperature of the molten glass to the temperature required for the defoaming treatment described above, and sufficient purifying effect can not be obtained.

It is an object of the present invention to provide a method of manufacturing a glass substrate and a glass substrate manufacturing apparatus capable of achieving both a purifying effect and a flow rate control of the molten glass both when the flow rate of the molten glass is large.

The present invention has the following aspects.

(Form 1)

A method of manufacturing a glass substrate using a processing apparatus for processing molten glass,

When processing the molten glass,

The processing apparatus is heated by energizing the processing apparatus so that the temperature of the molten glass in the processing apparatus is in a range suitable for the processing,

The flow rate of the molten glass in the processing apparatus is controlled by the amount of electric power at the time of energization,

The amount of heat released from the processing apparatus is adjusted so that the amount of electric power becomes equal to or more than a power amount capable of controlling the flow rate of the molten glass and the temperature of the molten glass becomes a temperature range in which the flow rate of the molten glass can be controlled. / RTI >

(Form 2)

When processing the molten glass,

The flow rate of the molten glass in the processing apparatus is controlled by the amount of current at the time of energization,

Wherein the amount of heat radiation from the processing apparatus to the outside is adjusted so that the flow rate of the molten glass is equal to or larger than the amount of current capable of controlling the flow rate of the molten glass.

Here, the flow rate of the molten glass refers to the amount of movement (volume or mass) of the molten glass per unit time.

Here, the processing apparatus includes a melting tank, a clarifying apparatus, a stirring tank and a molding apparatus, a transfer tube for transferring molten glass to these apparatus pipes, and a supply pipe for supplying glass to these apparatuses. The processing in the processing apparatus includes a melting process of glass, a refining process of molten glass, a stirring process, a molding process, and a transfer process and a supply process of molten glass.

(Form 3)

The processing apparatus has a vapor phase space formed from an inner wall and a molten glass liquid surface, and at least a portion of the inner wall which is in contact with the vapor phase space is made of a material containing a platinum group metal,

In the processing apparatus, a high-temperature region and a low-temperature region having a lower temperature than the high-temperature region are formed at the time of processing the molten glass,

And the amount of heat radiation is adjusted so that the temperature difference between the high temperature region and the low temperature region is 200 DEG C or less.

The platinum group metal means a metal composed of a single platinum group element and an alloy of a metal composed of a platinum group element. Platinum group elements are six elements of platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru), osmium (Os) and iridium (Ir).

For example, the high temperature region may be a region where the temperature of the processing apparatus is in a temperature range of 1600 占 폚 or more, and the low temperature region may be a region where the temperature of the processing apparatus is in a temperature range of less than 1600 占 폚. Alternatively, the high temperature region may be a region where the temperature of the processing apparatus is in a temperature range of 1620 占 폚 or higher, and the low temperature region may be a region where the temperature of the processing apparatus is within a temperature range of 1590 占 폚 or lower.

Alternatively, the region where the electrode formed in the processing apparatus is formed and the region where the exhaust pipe is formed are the low-temperature region, and the region other than the low-temperature region or the region between the electrode and the exhaust pipe may be the high-temperature region.

It is preferable to adjust the amount of heat radiation so that the maximum temperature in the high temperature region becomes 1600 to 1750 占 폚 and the lowest temperature in the low temperature region becomes 1300 to 1600 占 폚. By reducing the temperature difference between the high temperature region and the low temperature region, it is possible to reduce the amount of the platinum group metal volatilized in the high temperature region to aggregate in the low temperature region. The problem of incorporation of foreign matters derived from agglomerates of volatiles such as the above-mentioned platinum group metals into the molten glass is that in the glass substrates for displays typified by liquid crystal displays, It grows. Therefore, the above-described form is more preferable for a manufacturing method of a glass substrate for a display.

(Mode 4)

The processing apparatus is covered with a heat insulating material,

The method of manufacturing a glass substrate according to any one of modes 1 to 3, wherein the amount of heat radiation is controlled by adjusting thermal resistance from the processing device to an outer space by the heat insulating material.

(Mode 5)

Wherein the thermal resistance is adjusted by adjusting the thermal conductivity and the arrangement of the heat insulating material.

(Form 6)

The processing apparatus is a purifying apparatus for purifying a molten glass,

The cleaning device is heated by energizing the cleaning device so that a maximum temperature of the molten glass in the cleaning device is equal to or higher than a temperature at which a reduction reaction of tin oxide contained in the molten glass occurs, The method according to any one of modes 1 to 5, wherein the flow rate of the molten glass is controlled by the amount of power at the time of energization, and the amount of heat released from the refining apparatus to the outside is controlled so that the amount of power is equal to or more than a power amount capable of controlling the flow rate of the molten glass. Wherein the glass substrate is a glass substrate.

The maximum temperature of the molten glass in the processing apparatus is preferably 1630 캜 to 1720 캜. The maximum temperature of 1630 DEG C or higher enables the cleaning agent in the molten glass to exhibit the clarifying effect while the temperature difference of 1720 DEG C or lower can reduce the difference in temperature between the high temperature region and the low temperature region and reduce the amount of bubbles and the volatilization amount of the platinum group metal .

As the fining agent, it is preferable to use tin oxide. The content of tin oxide in the molten glass is preferably 0.01 to 0.3 mol%. If the content of tin oxide is too small, bubble reduction can not be sufficiently performed. On the other hand, if the content of tin oxide is too large, the volatilization amount of the tin oxide from the molten glass increases, and the volatile tin oxide aggregate is mixed into the molten glass. If the content of tin oxide is too large, the amount of oxygen released from the molten glass excessively increases, and the oxygen concentration in the gas phase rises, thereby causing a problem that the volatilization amount of the platinum group metal from the processing apparatus increases. By setting the content of tin oxide to 0.01 to 0.3 mol%, it is possible to sufficiently reduce bubbles and reduce the incorporation of tin oxide or an aggregate of platinum group metal into the molten glass. In addition, it is possible to reduce the volatilization amount of the platinum group metal from the processing apparatus while sufficiently reducing the bubbles.

(Form 7)

Wherein the cleaning device comprises a cleaning tube having a vapor phase space in which the bubbles in the molten glass are discharged, a first transfer tube through which the molten glass supplied into the cleaning tube is transferred, a second transfer tube through which the molten glass discharged from the cleaning tube is transferred Having a transfer pipe,

In the first conveyance pipe, the clarifying pipe and the second conveyance pipe, the degassing treatment of the molten glass by the reduction reaction of the refining agent and the absorption treatment of absorbing the bubbles in the molten glass by the oxidation reaction of the refining agent In addition,

The amount of electric power to be supplied to the first conveyance pipe, the amount of electric power to be supplied to the area of the purifying pipe and the second conveyance pipe to perform the defoaming treatment, and the amount of electric power to be supplied to the cleaning pipe Wherein the ratio of the amount of electricity to be energized in the region is 1: 0.6 to 1: 0.1 to 0.4.

(Form 8)

A defoaming treatment of the molten glass is carried out by a reducing reaction of the fining agent in a region of a part of the purifying tube,

An absorption treatment for absorbing the bubbles in the molten glass by the oxidation reaction of the fining agent is performed in another region of the cleaning tube and the second transfer tube,

Wherein the ratio of the amount of electric power to be supplied to the first conveying pipe to the amount of electric power to be supplied to the area of a part of the purifying pipe and the amount of electric power to be applied to the other area of the purifying pipe is 1: 0.6 to 1: (6).

(Mode 9)

The processing apparatus includes a cleaning tube having a vapor phase space in which molten glass is discharged, a first transfer tube through which the molten glass supplied into the cleaning tube is transferred, and a second transfer tube through which the molten glass discharged from the cleaning tube is transferred Having a transfer pipe,

The defoaming treatment of the molten glass is performed in the refining tube by a reducing reaction of the refining agent,

In the second conveyance pipe, an absorption treatment for absorbing bubbles in the molten glass is performed by the oxidation reaction of the cleaning agent,

The glass substrate according to the sixth aspect, wherein the ratio of the amount of electric power to be supplied to the first conveyance pipe, the amount of electric power to be supplied to the cleaning tube, and the amount of electric power to be supplied to the second conveyance pipe is 1: 0.6 to 1: 0.1 to 0.4 &Lt; / RTI >

In Forms 7 to 9, the region where the defoaming treatment is performed represents a region where the temperature becomes 1620 占 폚 or higher. The maximum temperature of the molten glass in the region where the defoaming treatment is performed is preferably from 1630 캜 to 1720 캜, more preferably from 1640 캜 to 1720 캜. The highest temperature of the treatment apparatus in the region where the defoaming treatment is performed is preferably 1630 캜 to 1750 캜, more preferably 1640 캜 to 1750 캜. By setting the temperature within this range, the volatilization of the platinum group metal can be reduced while sufficiently removing bubbles due to the reducing reaction of the fining agent.

In the form 7 to 9, the region where the absorption treatment is performed shows a region where the temperature becomes lower than 1620 占 폚. The temperature of the molten glass in the region to be subjected to the absorption treatment is preferably 1450 ° C to 1620 ° C. With this temperature range, the bubbles can be effectively absorbed by the oxidation reaction of the fining agent.

In Forms 7 to 9, the oxygen concentration in the vapor phase space is preferably 0 to 10%. By reducing the oxygen concentration, the volatilization amount of the platinum group metal can be reduced.

The vapor pressure of the platinum group metal in the vapor phase is preferably 0.1 Pa to 15 Pa. When the vapor pressure of the platinum group metal falls within this range, it is possible to prevent the reduced platinum group metal from adhering to the inner wall surface.

(Mode 10)

A processing device for processing the molten glass,

An energizing device for energizing the processing device by heating the molten glass so that the temperature of the molten glass in the processing device is in a range suitable for the processing,

And a control device for controlling the flow rate of the molten glass in the processing apparatus by the amount of electric power at the time of energization,

Wherein the amount of heat radiated from the processing apparatus to the outside is controlled such that the amount of electric power is equal to or more than a power amount capable of controlling the flow rate of the molten glass and the temperature of the molten glass becomes a temperature range in which the flow rate of the molten glass can be controlled. A glass substrate manufacturing apparatus.

(Mode 11)

A processing device for processing the molten glass,

And a control device for controlling the flow rate of the molten glass in the processing apparatus by the amount of current at the time of energization,

Wherein an amount of heat radiation from the processing apparatus to the outside is adjusted so that the flow rate of the molten glass is equal to or larger than the amount of current capable of controlling the flow rate of the molten glass.

(Form 12)

The processing apparatus has a vapor phase space formed from an inner wall and a molten glass liquid surface, and at least a portion of the inner wall which is in contact with the vapor phase space is made of a material containing a platinum group metal, Is a method of manufacturing a glass substrate or an apparatus for manufacturing a glass substrate according to any one of the first to eleventh aspects, wherein the non-inverse aspect ratio to the minimum length of the maximum length is 100 or more, for example. In addition, for example, the maximum length of the agglomerates of the platinum group metal is 50 탆 to 300 탆, and the minimum length is 0.5 탆 to 2 탆. Here, the maximum length of the aggregate of the platinum group metal refers to the length of the longest side of the circumscribed rectangle circumscribing the image of the foreign object obtained by photographing the aggregate of the platinum group metal, and the minimum length is the length of the minimum short side of the circumscribed rectangle.

Alternatively, the aggregates produced by the aggregation of the volatiles of the platinum group metal may have a ratio of a non-inference ratio to a minimum length of the maximum length of 100 or more, and a maximum length of aggregates of the platinum group metal of 100 m or more, Mu m.

(Form 13)

The method for manufacturing a glass substrate or the glass substrate producing apparatus according to any one of Forms 1 to 12, wherein the glass substrate is a glass substrate for display. It is also preferable for a glass substrate for an oxide semiconductor display or a glass substrate for an LTPS display.

According to the present invention, even when the flow rate of the molten glass is large, the purifying effect and the flow rate control of the molten glass can be realized.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a view showing an example of a process of a manufacturing method of a glass substrate of the present embodiment. FIG.
Fig. 2 is a diagram schematically showing an example of an apparatus for performing the dissolving step to the cutting step shown in Fig. 1. Fig.
3 is a schematic view showing the configuration of the cleaning tube 120. As shown in Fig.
4 is a cross-sectional view of the clarifying tube 120. Fig.

Hereinafter, a method of manufacturing a glass substrate and a glass substrate manufacturing apparatus of the present invention will be described.

1 is a view showing an example of a process of a manufacturing method of a glass substrate according to the present embodiment.

(Overview of Manufacturing Method of Glass Substrate)

The glass substrate manufacturing method includes a melting step (ST1), a refining step (ST2), a homogenizing step (ST3), a supplying step (ST4), a molding step (ST5), a slow cooling step (ST7). In addition, a plurality of glass substrates having a grinding process, a grinding process, a cleaning process, an inspection process, a packing process, and the like and stacked in the packaging process are returned to the supplier.

The dissolution step (ST1) is carried out in a dissolving tank. In the melting tank, a glass raw material is charged into the melt surface of the molten glass accumulated in the melting tank and heated to produce a molten glass. Further, the molten glass is flowed from the outlet formed at one bottom of the inner sidewall of the melting vessel toward the downstream process.

The heating of the molten glass in the melting tank may be accompanied by a flame by the burner to dissolve the glass raw material, in addition to the conduction heating, which is a method of heating the molten glass itself and heating it by itself. Further, the molten glass contains a refining agent. As the fining agent, tin oxide, arsenic acid, antimony, and the like are known, but there is no particular limitation. However, from the standpoint of environmental load reduction, it is preferable to use tin oxide as a refining agent. The content of tin oxide is preferably 0.01 to 0.3 mol%, more preferably 0.03 to 0.2 mol%. If the content of tin oxide is too small, bubble reduction can not be sufficiently performed. On the other hand, if the content of tin oxide is too large, the volatilization amount of the tin oxide from the molten glass increases, and the volatile tin oxide aggregate is mixed into the molten glass. If the content of tin oxide is too large, oxygen released from the molten glass excessively increases, and the volatilization amount of the platinum group metal from the processing apparatus is increased. By setting the content of tin oxide to 0.01 to 0.3 mol%, mixing of tin oxide aggregates into the molten glass can be reduced while sufficiently reducing bubbles. In addition, it is possible to reduce the volatilization amount of the platinum group metal from the processing apparatus while sufficiently reducing the bubbles.

Although tin oxide has a lower refining function than commonly used abiic acid, tin oxide can be preferably used as a refining agent in view of low environmental load. However, tin oxide has a lower refining function than that of avic acid. Therefore, when tin oxide is used, the temperature of the molten glass MG in the refining process of the molten glass MG must be higher than the conventional one. Further, since the maximum temperature of the molten glass is high, if the temperature of the low temperature region of the processing apparatus is raised to suppress the aggregation of the platinum group metal, the temperature of the molten glass becomes excessively high and the control of the flow rate by the current becomes difficult have. As a result, the amount of volatilization of the platinum group metal from the clarifying tube described later increases, and as a result, the problem that the platinum group metal is incorporated as a foreign substance on the glass substrate becomes remarkable.

The refining step (ST2) is carried out at least in the purifying tube. The refining process includes defoaming treatment and absorption treatment.

In the defoaming treatment, the temperature of the molten glass is raised so that the bubbles containing oxygen, CO ₂ or SO ₂ contained in the molten glass absorb the oxygen generated by the reduction reaction of the refining agent to increase the volume, . The defoaming treatment is carried out, for example, in the region of the treatment apparatus where the temperature of the molten glass becomes 1620 占 폚 or higher. The region of the processing apparatus where the temperature of the molten glass becomes 1620 DEG C or higher is referred to as " region subjected to defoaming treatment ". The temperature of the region where the defoaming treatment is performed is preferably 1620 to 1750 deg.

The maximum temperature of the molten glass in the region where the defoaming treatment is performed is preferably from 1630 캜 to 1720 캜, more preferably from 1640 캜 to 1720 캜. The highest temperature of the treatment apparatus in the region where the defoaming treatment is performed is preferably 1630 캜 to 1750 캜, more preferably 1640 캜 to 1750 캜. By setting the temperature within this range, the volatilization of the platinum group metal can be reduced while sufficiently removing bubbles due to the reducing reaction of the fining agent.

In the absorption treatment, by reducing the temperature of the molten glass, the reducing material obtained by the reduction reaction of the fining agent performs the oxidation reaction. As a result, gas components such as oxygen in the bubbles remaining in the molten glass are reabsorbed into the molten glass, and the bubbles disappear. The absorption treatment is carried out in a region on the downstream side of the region where the defoaming treatment of the treatment apparatus is performed and in which the temperature of the molten glass becomes less than 1620 占 폚. The region of the processing apparatus in which the temperature of the molten glass becomes less than 1620 占 폚 is referred to as " region to be subjected to the absorption process ". The temperature of the region to be subjected to the absorption treatment is preferably 1450 ° C or higher and lower than 1620 ° C.

The temperature of the molten glass in the region to be subjected to the absorption treatment is preferably 1450 ° C to 1620 ° C. With this temperature range, the bubbles can be effectively absorbed by the oxidation reaction of the fining agent.

The oxidation reaction and the reduction reaction by the refining agent are carried out by controlling the temperature of the molten glass. In the finishing step of the present embodiment, a clarifying method using tin oxide as a fining agent will be described.

The purifying step may be a vacuum degassing method in which a space in a reduced pressure atmosphere is made in a purifying tube and bubbles present in the molten glass are grown in a reduced pressure atmosphere and defoamed. In this case, it is effective in that a refining agent is not used. However, in the vacuum degassing system, since the apparatus becomes complicated and large, it is preferable to employ a refining method of raising the temperature of the molten glass by using a refining agent.

In the homogenization step (ST3), the molten glass in the stirring tank supplied through the pipe extending from the purifying tube is homogenized by stirring using a stirrer. Thereby, it is possible to reduce unevenness in the composition of the glass, which is a cause of malty or the like.

In the supplying step (ST4), the molten glass is supplied to the molding apparatus through the pipe extending from the stirring tank.

The molding step (ST5) and the slow cooling step (ST6) are carried out in a molding apparatus.

In the molding step (ST5), the molten glass is formed into a sheet glass to form a flow of the sheet glass. For forming, an overflow down-draw method is used.

In the slow cooling step (ST6), the formed sheet glass is cooled to a desired thickness so that internal deformation does not occur and no warping occurs.

In the cutting step (ST7), in the cutting apparatus, the sheet glass supplied from the molding apparatus is cut to a predetermined length to obtain a plate-like glass substrate. The cut glass substrate is further cut into a predetermined size to produce a glass substrate having a target size.

Fig. 2 is a diagram schematically showing an example of an apparatus for performing the dissolving step (ST1) to the cutting step (ST7) in the present embodiment. As shown in FIG. 2, this apparatus mainly has a dissolving apparatus 100 and a molding apparatus 200. The melting apparatus 100 has a melting vessel 101, a cleaning tube 120, a stirring tank 103, a first conveyance pipe 104, a second conveyance pipe 105 and a glass feed pipe 106.

A heating means such as a burner (not shown) is formed in the dissolution tank 101 shown in Fig. In the melting tank, a glass raw material to which a refining agent is added is introduced, and a melting process is carried out. The molten glass melted in the melting tank 101 is supplied to the cleaning tube 120 through the transfer tube 104.

In the cleaning tube 120, the temperature of the molten glass MG is adjusted, and the refining process of the molten glass is performed using the redox reaction of the cleaning agent. The molten glass after the refining is supplied to the stirring tank through the transfer pipe 105. During the refining process, the degassing process may be performed in the transfer pipe 104. That is, the transfer pipe 104 may have a " region for performing defoaming processing ". In the refining process, the absorption process may be performed in the transfer pipe 105. That is, the transfer tube 105 may have an " area where absorption processing is performed ".

Electrodes 121a and 121b are formed in the cleaning tube 120. Current is supplied to the cleaning tube 120 between the electrodes 121a and 121b by applying a voltage between the electrodes 121a and 121b, The tube 120 is energized and heated. In addition, electrodes (not shown) are formed at both ends of the first conveyance pipe 104 and the second conveyance pipe 105. By applying a voltage between the electrodes, the first conveyance pipe 104 and the second conveyance pipe A current flows in the first conveyance pipe 105 and the first conveyance pipe 104 and the second conveyance pipe 105 are energized and heated. The electrodes 121a and 121b preferably have a flange shape from the viewpoint of preventing breakage due to overheating. In the case of the cleaning pipe 120 of the present embodiment, since the electrodes 121a and 121b having a flange shape have a high heat radiation function, the wall in the vicinity of the electrodes 121a and 121b, It becomes low temperature. The electrodes 121a and 121b are cooled by a liquid or a gas in order to suppress breakage due to, for example, overheating. Therefore, the temperature of the wall of the cleaning tube 120 in contact with the vapor phase inevitably has a temperature profile along the flow direction of the molten glass. In other words, in the case of the cleaning tube 120 of the present embodiment, the temperature of the cleaning tube 120 is not constant, and inevitably a temperature difference is generated.

The amount of electric power to be supplied to the first conveying pipe 104, the amount of electric power to be supplied to the area of the cleaning pipe 120 to be subjected to the defoaming treatment, the amount of electricity to be supplied to the cleaning pipe 120 and the second conveying pipe 105 The ratio of the electric power to be energized is preferably 1: 0.6 to 1: 0.1 to 0.4, more preferably 1: 0.7 to 1: 0.15 to 0.4.

When the defoaming treatment is performed in a part of the cleaning tube 120 and the absorption treatment is performed in the other area of the cleaning tube 120 and the second conveyance pipe 105, The ratio of the amount of electricity to be supplied to the cleaning tube 120 to the area where the defoaming treatment of the cleaning tube 120 is performed and the amount of electricity to be supplied to the area where the absorption treatment of the cleaning tube 120 is performed is 1: 0.6 to 1 : 0.1 to 0.4, more preferably 1: 0.7 to 1: 0.15 to 0.4.

When the degassing treatment is performed in the cleaning tube 120 and the absorption treatment is performed only in the second conveyance pipe 105, the amount of electric power to be applied to the first conveyance pipe 104, The ratio of the amount of electric power to be supplied to the first conveying pipe 105 to the amount of electric power to be supplied to the second conveying pipe 105 is preferably 1: 0.6 to 1: 0.1 to 0.4, more preferably 1: 0.7 to 1: 0.15 to 0.4.

In the stirring tank 103, molten glass is stirred and homogenized by a stirrer 103a. The molten glass homogenized in the stirring tank 103 is supplied to the molding apparatus 200 through the glass supply pipe 106.

In the molding apparatus 200, the sheet glass is formed from the molten glass by the overflow down-draw method.

(Composition of the ceremony hall)

Next, the configuration of the cleaning tube 120 will be described with reference to Fig. 3 is a schematic view showing the configuration of the cleaning tube 120 of the embodiment.

Electrodes 121a and 121b are formed on the outer circumferential surfaces at both ends in the longitudinal direction of the clarifying pipe 120. An exhaust pipe 127 is formed on the wall contacting the vapor phase space of the purifying pipe 120 Respectively. Further, the cleaning tube 120 is preferably made of platinum, reinforced platinum or platinum alloy.

In this specification, the term " platinum group metal " means a metal composed of a platinum group element, and is used as a term including not only a metal composed of a single platinum group element but also an alloy of a platinum group element. Here, the platinum group element represents six elements of platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru), osmium (Os) and iridium (Ir). Although platinum group metals are expensive, they have a high melting point and excellent corrosion resistance to molten glass.

In the present embodiment, a case where the cleaning tube 120 is made of a platinum group metal will be described as a specific example. However, a part of the cleaning tube 120 may be made of refractory material, another metal, or the like.

The electrodes 121a and 121b are connected to the power source device 122. [ A voltage is applied between the electrodes 121a and 121b so that a current flows through the cleaning tube 120 between the electrodes 121a and 121b and the cleaning tube 120 is energized and heated. By this energization heating, the maximum temperature of the cleaning tube 120 is heated to, for example, 1600 ° C to 1750 ° C, more preferably 1630 ° C to 1750 ° C, and the molten material supplied from the first transfer tube 104 The maximum temperature of the glass is heated to a temperature suitable for the defoaming treatment, for example, 1630 캜 to 1720 캜.

In addition, by controlling the temperature of the molten glass by conduction heating, the viscosity of the molten glass in the purifying pipe 120 can be controlled, thereby controlling the flow rate of the molten glass passing through the purifying pipe 120. In order to control the flow rate of the molten glass, the target amount of electric power to be applied to the cleaning tube 120 is more preferably 5 kW or more, and preferably 10 kW or more. In particular, it is preferable that the target amount of electric power to be applied to the outlet of the cleaning tube 120 is 5 kW or more, more preferably 8 kW or more. By setting the power amount in the above range, the flow rate of the molten glass can be adjusted by the amount of power.

A temperature measuring device (thermocouple, etc.) (not shown) may be formed on the electrodes 121a and 121b. The temperature measuring device measures the temperature of the electrodes 121a and 121b and outputs the measurement result to the control device 123. [

The control device 123 is a computer including a CPU, a memory, and the like. The control device 123 controls the amount of electric current and the amount of electric power that the power source device 122 conducts to the cleaning tube 120. Thereby, the control device 123 can control the temperature and the flow rate of the molten glass in the purifying pipe 120.

An exhaust pipe 127 is formed on a wall of the purifying pipe 120 in contact with the vapor space. The exhaust pipe 127 may protrude outwardly from the outer wall surface of the purifying pipe 120 in the form of a chimney. The exhaust pipe 127 communicates the vapor space 120a, which is a part of the inner space of the purifying pipe 120, with the outer space of the purifying pipe 120.

4 is a sectional view of the cleaning tube 120 in the longitudinal direction of the main body of the cleaning tube 120 and in the longitudinal direction of the exhaust tube 127. [ A heat insulating material 140 is formed on the outer wall surface of the body of the cleaning tube 120, the outer wall surface of the electrodes 121a and 121b and the outer wall surface of the exhaust pipe 127. [

The heat insulating material 140 supports the cleaning tube 120 so as not to be deformed and also serves to keep the cleaning tube 120 warm. As the heat insulating material 140, a member having excellent fire resistance and sufficiently high strength (rigidity) can be used.

In order to control the amount of heat radiation from the cleaning tube 120 with good precision, it is preferable to use a material having a different thermal conductivity as the heat insulating material 140. For example, the first heat insulator is disposed in a region promoting the heat radiation of the cleaning tube 120 by using the first heat insulator having a higher thermal conductivity and the second heat insulator having a lower thermal conductivity, The amount of heat radiation from each area of the cleaning tube 120 can be adjusted by using the double insulation material.

It is not necessary to form the first insulating material so as to be in contact with the entire area of the cleaning tube 120. It is preferable to selectively form the heat transfer medium 130 at a point contacting at least the high temperature region and a point contacting the low temperature region and forming the heat transfer medium 130 so as to connect the both.

The thermal conductivity of the first thermal insulator is preferably at least two times the thermal conductivity of the second thermal insulator, more preferably at least five times.

It is preferable to use a material having a thermal conductivity of 2 to 40 W / m 占 에 at 1000 占 폚 for the first heat insulator. Specifically, alumina electroform refractory, magnesia refractory, silicon carbide refractory, or the like can be used as the first heat insulator.

It is preferable to use a material having a thermal conductivity of 0.1 to 1 W / m 占 에 at 1000 占 폚 for the second heat insulator. Specifically, porous bricks, ceramic fibers and the like can be used as the second heat insulating material.

The amount of heat radiation from the cleaning tube 120 to the outside is adjusted so that the temperature and the flow rate of the molten glass can be controlled while the current is supplied to the cleaning tube 120 so that the control device 123 is higher than or equal to the target amount of electric current have. This amount of heat radiation is the amount of heat radiation required when the flow rate of the molten glass passing through the cleaning tube 120 becomes maximum. The amount of heat radiation can be controlled by adjusting the heat resistance from the cleaning tube 120 to the outer space. For example, the thermal resistance can be adjusted by adjusting the thermal conductivity or the arrangement of the first heat insulator and the second heat insulator used as the heat insulator 140.

By lowering the thermal resistance from the cleaning tube 120 to the outer space, the thermal conduction from the cleaning tube 120 to the outer space is facilitated through the thermal insulating material 140. Thereby, the amount of electric power to be supplied to the cleaning tube becomes equal to or larger than the amount of electric power capable of controlling the flow rate of the molten glass, and even when the flow rate of the molten glass passing through the cleaning tube 120 is large, the flow rate of the molten glass can be controlled have.

The temperature difference between the high-temperature region and the low-temperature region of the cleaning tube 120 is preferably not less than 50 ° C and not more than 200 ° C, more preferably not less than 70 ° C but not more than 150 ° C from the viewpoint of both suppressing the volatilization of the platinum group metal and purifying effect desirable. Here, the high-temperature region refers to a region having a higher temperature than the other regions. In the case of the purifying pipe 120, for example, the high-temperature region may be a region in which the temperature of the purifying pipe 120 is in a temperature range of 1600 占 폚 or more, or a region in a temperature range of 1620 占 폚 or more. Further, for example, the high-temperature region may include a region where the purifying tube 120 becomes the highest temperature when processing the molten glass. The low-temperature region refers to a region having a lower temperature than the other regions, specifically, a region having a lower temperature than the high-temperature region. In the case of the purifying tube 120, the low temperature region may be a region where the temperature of the purifying tube 120 is in a temperature range of less than 1600 占 폚, or a region in a temperature range of 1590 占 폚 or less. Further, for example, the low-temperature region may include a region where the cleaning tube 120 becomes the lowest temperature when processing the molten glass. For example, the connecting portion of the cleaning pipe 120 with the electrodes 121a and 121b and the connecting portion with the exhaust pipe 127 are arranged such that heat radiation from the electrodes 121a and 121b and the exhaust pipe 127 to the outside It is liable to be lower in temperature than other regions of the purifying tube 120. [ That is, a region where the cleaning tube is connected to the electrodes 121a and 121b and a region where the cleaning tube is connected to the exhaust pipe 127 is a low temperature region, and a region between the electrodes 121a and 121b and the exhaust pipe 127 , And becomes a high-temperature region.

The minimum temperature in the low-temperature region is preferably 1300 DEG C or higher and 1600 DEG C or lower, more preferably 1400 DEG C or higher and 1600 DEG C or lower, and more preferably 1500 DEG C or higher and 1600 DEG C or lower in order to set the temperature difference between the high- Do. The highest temperature in the high temperature region is preferably 1600 DEG C or higher and 1750 DEG C or lower, more preferably 1600 DEG C or higher and 1720 DEG C or lower, and still more preferably 1610 DEG C or higher and 1700 DEG C or lower.

However, when molten glass passes through a processing apparatus using a platinum group metal on the inner wall surface, the platinum group metal is volatilized as an oxide in a portion contacting the vapor space (atmosphere containing oxygen) of the heated inner surface. For example, in the purifying tube 120 made of a platinum group metal, the platinum group metal is oxidized and volatilized in the vapor phase space. This volatilization is particularly noticeable in the high temperature region of the purifying tube 120. On the other hand, the platinum group metal oxide is reduced at a locally decreased temperature (for example, around the electrode) of the treatment apparatus, and the reduced platinum group metal coagulates and adheres to the inner wall surface (flocculates). The aggregate of the platinum group metal adhered to the inner wall surface falls into the molten glass and is mixed as a foreign substance, thereby deteriorating the quality of the glass substrate. Particularly, when tin oxide is used as a refinishing agent, the highest temperature required for obtaining the refining effect becomes high, so that the problem of volatilization and adhesion becomes more significant. For this reason, it is conceivable to prevent the agglomeration of the platinum group metal by raising the temperature of the locally lowered temperature region (low temperature region) of the treatment apparatus. When the temperature difference between the high temperature region and the low temperature region is 200 DEG C or lower, preferably 150 DEG C or lower, reduction of the oxidized platinum group metal oxide in the high temperature region can be reduced in the low temperature region, It is hardly to be mixed into the water.

When the oxygen concentration in the gas phase space is 0%, the volatilization of the platinum group metal can be prevented. Therefore, from the viewpoint of preventing the volatilization of the platinum group metal, it is preferable to set the oxygen concentration in the vapor phase space to 0%. However, in order to always keep the oxygen concentration in the vapor phase at 0%, there is a problem that the content of the fining agent is extremely reduced, and a cost is incurred. For this reason, it is preferable that the oxygen concentration in the vapor phase space is 0.01% or more in order to reduce bubbles, reduce the cost, and reduce volatilization of the platinum group metal. When the oxygen concentration in the gas phase space becomes too small, the difference in oxygen concentration between the molten glass and the gas phase increases, oxygen released from the molten glass into the gas phase increases, and the molten glass is excessively reduced. As a result, Or air bubbles such as nitrogen may remain. On the other hand, if the oxygen concentration is too large, the volatilization of the platinum group metal is promoted, and there is a fear that the deposition amount of the volatile platinum group metal increases. From the above, the oxygen concentration in the vapor phase space is preferably 0 to 30%, more preferably 0.1 to 10%, even more preferably 0.1 to 1%.

The vapor pressure of the platinum group metal in the vapor phase space is preferably 0.1 Pa to 15 Pa, more preferably 3 Pa to 10 Pa. When the vapor pressure of the platinum group metal falls within this range, it is possible to suppress the adhesion of the reduced platinum group metal aggregate to the inner wall surface.

On the other hand, when the temperature in the low temperature region is raised, the molten glass that has been cooled in the low temperature region is not cooled, and the molten glass having a temperature higher than the target temperature flows out downstream. It is necessary to reduce the amount of heating in subsequent steps by raising the temperature in the low temperature region since the optimum temperature is determined as the molten glass that flows out downstream.

In the purifying tube 120, in order to prevent reduction of platinum, when the amount of current to the electrodes 121a and 121b is increased to raise the temperature in the vicinity of the electrodes 121a and 121b in the low temperature region, And the amount of heating on the downstream side of the purifying pipe 120 becomes smaller, so that it becomes impossible to adjust the flow rate.

According to the present embodiment, the temperature difference between the high temperature region and the low temperature region can be adjusted by adjusting the heat conductivity, arrangement and amount of the heat insulating material 140. Thereby, it is possible to avoid that the flow rate can not be adjusted by raising the electric current flow rate to the electrodes 121a, 121b.

The amount of heat when the heat conductivity, the arrangement and the amount of the heat insulating material 140 are changed can be calculated, for example, by numerical fluid-dynamic computation (computer simulation) using a 3D model produced by the finite element method or the mesh free method . For example, a 3D model in which the molten glass and the vapor phase space in the cleaning tube 120, the heat insulating material 140, and the cleaning tube 120 are reproduced is divided into a finite number of regions (calculation grids) (The temperature of the molten glass and the gaseous space in the purifying tube 120, the temperature of the external space, etc.) and the material properties (thermal conductivity, etc.). Next, by using the iterative calculation by the computer, the entrance / exit of the heat quantity in each calculation lattice is analyzed. By using the computer simulation, it is possible to easily and economically calculate the optimum thermal conductivity, arrangement, and amount of the heat insulator 140.

The aggregate of the platinum group metal to be suppressed in the present embodiment forms a linear shape in one direction and has an aspect ratio of 100 or more as a ratio to the minimum length of the maximum length. For example, the maximum length of agglomerates of platinum group metals is 50 탆 to 300 탆, and the minimum length is 0.5 탆 to 2 탆. Here, the maximum length of the aggregate of the platinum group metal refers to the length of the longest side of the circumscribed rectangle circumscribing the image of the foreign object obtained by photographing the aggregate of the platinum group metal, and the minimum length is the length of the minimum short side of the circumscribed rectangle.

(Experimental Example 1)

A glass substrate having a thickness of 0.5 mm and a size of 2270 mm x 2000 mm was produced by using tin oxide as a fining agent and using the production apparatus of the above embodiment. Further, the glass substrate has a glass composition, SiO ₂ 66.6% by mole, Al ₂ O ₃ 10.6 mol%, B ₂ O ₃ 11.0 total amount of 11.4 mol% of the mole%, MgO, CaO, SrO and BaO, SnO ₂ 0.15 mol%, 0.05 mol% of Fe ₂ O ₃ and 0.2 mol% of an alkali metal oxide, and the temperature of the molten glass at a strain point of 660 ° C. and a viscosity of 10 ^2.5 poise was 1570 ° C. The ratio of the amount of electric power to be supplied to the first conveyance pipe 104, the amount of electric power to be supplied to the cleaning tube 120 and the amount of electric power to be supplied to the second conveyance pipe 105 can be adjusted by adjusting the amount of heat radiation from the cleaning tube to the outside, Was 1: 0.8: 0.3. As a result, the glass substrate having the number of bubbles equal to or less than the specified number could be produced without melting the molten glass from the processing apparatus. In addition, the number of foreign substances of the platinum group metal incorporated into the glass substrate can be suppressed to 0.001 / kg or less. In addition, as the foreign substance of the platinum group metal, those having an aspect ratio of 100 or more and a maximum length of 100 占 퐉 or more were counted.

(Experimental Example 2)

The glass composition of the glass substrate to be produced was changed to 70 mol% of SiO ₂ , 12.9 mol% of Al ₂ O ₃ , 2.5 mol% of B ₂ O ₃ , 3.5 mol% of MgO, 6 mol% of CaO, 1.5 mol% of SrO, , 3.5 mol% of BaO, and 0.1 mol% of SnO ₂ , the glass substrate was prepared in the same manner as in Experimental Example 1. At this time, the strain point of the glass substrate was 745 캜.

As a result, it was found that even if a glass substrate having a high strain point and a higher refining temperature than that of Experimental Example 1 was produced, a glass substrate having a number of bubbles less than or equal to a specified number could be manufactured without overflowing from the processing apparatus I could. It was also found that the number of the platinum group metal incorporated into the glass substrate can be suppressed to 0.001 / kg or less.

(Comparative Example)

A glass substrate was prepared in the same manner as in Experimental Example 1 except that the amount of heat radiation from the cleaning tube to the outside was not adjusted. At this time, the ratio of the amount of electric power to be supplied to the first conveyance pipe 104, the amount of electricity to be supplied to the cleaning tube 120, and the amount of electricity to be supplied to the second conveyance pipe 105 is 1: 1.5: 0.05 Respectively. As a result, the number of bubbles containing nitrogen or sulfur oxide was more than the specified number.

(Glass composition)

If the alkali-free glass substrate containing tin oxide or the micro-alkali glass substrate containing tin oxide is used, the effect of the present embodiment becomes remarkable. The alkali-free or micro-alkali glass has a higher glass viscosity than the alkali glass. For this reason, it is necessary to increase the melting temperature in the dissolving step, and a large amount of tin oxide is reduced to the dissolving step. Therefore, in order to obtain the refining effect, the temperature of the molten glass in the refining step is increased, It is necessary to lower the viscosity of the molten glass. That is, in the case of producing a non-alkali glass substrate containing tin oxide or a micro alkali glass substrate containing tin oxide, since it is necessary to raise the temperature of the molten glass in the refining step, the flow rate of the molten glass It is difficult to control by the amount of electric power at the time of energizing the processing apparatus, and the volatilization of the platinum group metal (for example, platinum or platinum alloy) is likely to occur. Herein, in the present specification, the alkali-free glass substrate is a glass substantially containing no alkali metal oxide (Li ₂ O, K ₂ O, and Na ₂ O). The micro alkali glass is a glass having a content of alkali metal oxide (sum of Li ₂ O, K ₂ O, and Na ₂ O) of more than 0 and less than 0.8 mol%.

As the glass substrate manufactured in this embodiment, a glass substrate having the following glass composition is exemplified. Therefore, the glass raw materials are combined so that the following glass composition is contained in the glass substrate. For example, the glass substrate produced in this embodiment may contain 55 to 75 mol% of SiO ₂ , 5 to 20 mol% of Al ₂ O ₃ , 0 to 15 mol% of B ₂ O ₃ , 5 to 20 mol% of RO is the total amount of MgO, CaO, SrO and _{BaO), R '2 O 0} ~ 0.4 mol% of (R' is Li ₂ O, K ₂ O, and the total amount), SnO ₂ 0.01 ~ 0.4 mol% of Na ₂ O, containing do.

At this time, at least one of SiO ₂ , Al ₂ O ₃ , B ₂ O ₃ , and RO (R is any of the elements contained in the glass substrate among Mg, Ca, Sr, and Ba) × SiO ₂ ) + Al ₂ O ₃ ) / ((2 × B ₂ O ₃ ) + RO) may be 4.0 or more. A glass having a molar ratio ((2 x SiO ₂ ) + Al ₂ O ₃ ) / ((2 x B ₂ O ₃ ) + RO) of 4.0 or more is an example of a glass having a high temperature viscosity. It is difficult to control the flow rate of the molten glass by the amount of electric power at the time of energizing the processing apparatus and the volatilization of the platinum group metal occurs easy to do. That is, in the case of manufacturing a glass substrate having such a composition, the amount of heat released from the processing apparatus to the outside is controlled so that the temperature of the molten glass can be controlled within the temperature range in which the flow rate of the molten glass can be controlled. The effect of the present embodiment such as making it easier to control by the amount of electric power at the time of energization, suppressing mixing of the platinum group metal aggregate into the molten glass as a foreign substance, and adjusting the flow rate of the molten glass by the amount of electric power becomes remarkable. The high-temperature viscosity refers to the viscosity of the glass when the molten glass is heated to a high temperature. For example, the high temperature means 1,300 ° C or more.

According to this embodiment, even if the content of the alkali metal oxide in the glass substrate is 0 to 0.8 mol%, the flow rate of the molten glass can be controlled by the amount of electric power, and the aggregation of the platinum group metal in the molten glass . The glass having a content of the alkali metal oxide of 0 to 0.8 mol% has a high-temperature viscosity higher than that of the glass having the alkali metal oxide content of more than 0.8 mol%, since the lower the content of the alkali metal oxide is, . It is difficult to control the flow rate of the molten glass by the amount of electric power to be supplied to the processing apparatus and the volatilization of the platinum group metal is liable to occur because the temperature of the molten glass in the refining step is generally high . In other words, when the high-temperature high-viscosity glass is used, it is possible to prevent the aggregation of the platinum group metal from being mixed into the molten glass as a foreign substance, while preventing the temperature of the molten glass from reaching the outside The effect of the present embodiment that the control by the amount of electric power when the flow rate of the molten glass is conducted to the processing apparatus can be easily performed is remarkable.

The molten glass used in the present embodiment may be a glass composition having a viscosity of 1500 to 1700 占 폚 at a viscosity of 10 ^2.5 poise. As described above, it is generally necessary to increase the temperature of the molten glass in the refining process. Therefore, it is difficult to control the flow rate of the molten glass by the amount of power supplied to the processing apparatus, It is easy to occur. That is, even if the glass composition has a high-temperature viscosity, the above effect of the present embodiment becomes remarkable.

The deformation point of the molten glass used in the present embodiment may be 650 캜 or higher, more preferably 660 캜 or higher, still more preferably 690 캜 or higher, and particularly preferably 730 캜 or higher. Further, the glass having a high strain point tends to have a high temperature of the molten glass at a viscosity of 10 ^2.5 poise. That is, the effect of the present embodiment becomes more remarkable when the glass substrate having a high strain point is produced. Further, since a glass having a high strain point is used for a fixed three display, there is a strict demand for a problem that a platinum group metal aggregate is mixed as a foreign substance. Therefore, the glass substrate having a high strain point is more preferable in the present embodiment in which incorporation of aggregates of the platinum group metal can be suppressed.

Further, when the glass raw material is melted so as to be a glass containing tin oxide and having a viscosity of 10 ^2.5 poise and a molten glass temperature of 1500 ° C or higher, the above effect of the present embodiment becomes more remarkable and the viscosity becomes 10 The temperature of the molten glass in the case of ^2.5 foams is, for example, 1500 to 1700 占 폚, and may be 1550 to 1650 占 폚.

When the aggregate of the platinum group metal located on the surface of the glass substrate is removed in the panel manufacturing process using the glass substrate, the separated portion is recessed, the thin film formed on the glass substrate is not uniformly formed, There is a problem of causing defects. Further, when aggregates of platinum group metals are present in the glass substrate, deformation occurs due to the difference in thermal expansion coefficient between the glass and the platinum group metal in the slow cooling step, which causes display defects on the screen. Therefore, the present embodiment is preferable for manufacturing a glass substrate for a display in which there is a strict demand for screen display defects. In particular, glass substrates for oxide semiconductor displays using oxide semiconductors such as IGZO (indium, gallium, zinc, oxygen) and LTPS displays using LTPS (low temperature polysilicon) semiconductors, And is preferable for a glass substrate for three fixed displays such as a substrate.

From the above, the glass substrate manufactured in this embodiment is preferable for a glass substrate for a display including a glass substrate for a flat panel display. A glass substrate for an oxide semiconductor display or a glass substrate for an LTPS display. Further, the glass substrate produced in this embodiment is preferable for a glass substrate for a liquid crystal display which requires a very small content of alkali metal oxide. It is also preferable for a glass substrate for an organic EL display. In other words, the manufacturing method of the glass substrate of the present embodiment is preferable for manufacturing a glass substrate for a display, and is particularly preferable for manufacturing a glass substrate for a liquid crystal display.

Further, the glass substrate manufactured in this embodiment can be applied to a cover glass, a glass for a magnetic disk, a glass substrate for a solar cell, and the like.

Although the method of manufacturing the glass substrate of the present invention has been described in detail above, the present invention is not limited to the above-described embodiments, and it is needless to say that various modifications and changes may be made without departing from the gist of the present invention .

For example, though not shown, a circulation pipe of a refrigerant may be formed between the vicinity of the purifying pipe 120 and the outside of the heat insulating material 140, and the amount of heat radiation may be adjusted by circulating the refrigerant in the circulation pipe. In this case, the heat radiation amount can be adjusted by controlling the circulation amount of the refrigerant.

The refrigerant circulated through the circulation pipe may be a liquid such as water or a gas such as air.

A metal material having a high melting point can be used for the circulation tube. Specifically, platinum, rhodium, silver, palladium, gold, or an alloy thereof may be used as the material of the circulation tube.

The present invention is not limited to the purifying tube 120 but may be applied to other parts of the dissolving apparatus 100 such as the melting vessel 101, the stirring vessel 103, The amount of heat radiation from the transfer tubes 104 and 105, the glass supply tube 106, and the molding apparatus 200 may be adjusted.

101: Melting bath
103: stirring tank
104, 105: transfer pipe
106: Glass feed pipe
120: Purification pipe (purifying device)
121a and 121b:
122: Power supply
123: control device
127: Exhaust pipe
140: Insulation
200: forming device

Claims

A method of manufacturing a glass substrate using a processing apparatus for processing molten glass,
When processing the molten glass,
The processing apparatus is heated by energizing the processing apparatus so that the temperature of the molten glass in the processing apparatus is in a range suitable for the processing,
The flow rate of the molten glass in the processing apparatus is controlled by the amount of electric power at the time of energization,
Wherein the amount of electric power is an amount of electric power capable of controlling the flow rate of the molten glass and is equal to or larger than a target amount of electric power that can not control the flow rate below the amount of electric power and in which the temperature of the molten glass is a temperature And the amount of heat radiation from the processing apparatus to the outside is adjusted.

A method of manufacturing a glass substrate using a processing apparatus for processing molten glass,
When processing the molten glass,
The processing apparatus is heated by energizing the processing apparatus so that the temperature of the molten glass in the processing apparatus is in a range suitable for the processing,
The flow rate of the molten glass in the processing apparatus is controlled by the amount of current at the time of energization,
Wherein the amount of heat released from the processing apparatus to the outside is controlled so that the amount of current capable of controlling the flow rate of the molten glass becomes equal to or larger than a target amount of current that can not control the flow rate below the amount of the current.

3. The method according to claim 1 or 2,
The processing apparatus has a vapor phase space formed from an inner wall and a molten glass liquid surface, and at least a portion of the inner wall which is in contact with the vapor phase space is made of a material containing a platinum group metal,
The processing apparatus is provided with a high-temperature region when processing the molten glass and a low-temperature region having a temperature lower than that of the high-temperature region when the molten glass is processed,
And the amount of heat radiation is adjusted so that the temperature difference between the high temperature region and the low temperature region is 200 DEG C or less.

3. The method according to claim 1 or 2,
The processing apparatus is covered with a heat insulating material,
And the heat radiation amount is controlled by adjusting the thermal resistance from the processing device to the external space by the heat insulating material.

5. The method of claim 4,
Wherein the thermal resistance is adjusted by adjusting the thermal conductivity and the arrangement of the heat insulating material.

3. The method according to claim 1 or 2,
The processing apparatus is a purifying apparatus for purifying a molten glass,
The clarifying apparatus is heated by energizing the clarifying apparatus so that the maximum temperature of the molten glass in the clarifying apparatus is equal to or higher than a temperature at which a reducing reaction of tin oxide contained in the molten glass occurs,
The flow rate of the molten glass in the refining apparatus is controlled by the amount of electric power at the time of energization,
Wherein the amount of heat released from the clarifying apparatus to the outside is adjusted so that the amount of power is equal to or more than a power amount capable of controlling the flow rate of the molten glass.

The method according to claim 6,
Wherein the cleaning device comprises a cleaning tube having a vapor phase space in which the bubbles in the molten glass are discharged, a first transfer tube through which the molten glass supplied into the cleaning tube is transferred, a second transfer tube through which the molten glass discharged from the cleaning tube is transferred Having a transfer pipe,
In the first conveyance pipe, the clarifying pipe and the second conveyance pipe, the degassing treatment of the molten glass by the reduction reaction of the refining agent and the absorption treatment of absorbing the bubbles in the molten glass by the oxidation reaction of the refining agent In addition,
The amount of electric power to be supplied to the area of the purifying pipe to be subjected to the defoaming treatment and the amount of electric power to be supplied to the area of the purifying pipe and the second conveying pipe Wherein the ratio is 1: 0.6 to 1: 0.1 to 0.4.

The method according to claim 6,
Wherein the cleaning device comprises a cleaning tube having a vapor phase space in which the bubbles in the molten glass are discharged, a first transfer tube through which the molten glass supplied into the cleaning tube is transferred, a second transfer tube through which the molten glass discharged from the cleaning tube is transferred Having a transfer pipe,
A defoaming treatment of the molten glass is carried out by a reducing reaction of the fining agent in a region of a part of the purifying tube,
An absorption treatment for absorbing the bubbles in the molten glass by the oxidation reaction of the fining agent is performed in another region of the cleaning tube and the second transfer tube,
Wherein a ratio of an amount of electric power to be supplied to the first conveyance pipe, an amount of electric power to be applied to a region of a part of the clarifying tube and an amount of electric power to be applied to another region of the clarifying tube is 1: 0.6 to 1: 0.05 to 0.4, / RTI >

The method according to claim 6,
The processing apparatus includes a cleaning tube having a vapor phase space in which molten glass is discharged, a first transfer tube through which the molten glass supplied into the cleaning tube is transferred, and a second transfer tube through which the molten glass discharged from the cleaning tube is transferred Having a transfer pipe,
The defoaming treatment of the molten glass is performed in the refining tube by a reducing reaction of the refining agent,
In the second conveyance pipe, an absorption treatment for absorbing bubbles in the molten glass is performed by the oxidation reaction of the cleaning agent,
Wherein a ratio of an amount of electric power to be energized to the first conveyance pipe, an amount of electric power to be energized to the cleaning tube, and an amount of electric power to be energized to the second conveyance pipe is 1: 0.6 to 1: 0.1 to 0.4.

A processing device for processing the molten glass,
An energizing device for energizing the processing device by heating the molten glass so that the temperature of the molten glass in the processing device is in a range suitable for the processing,
And a control device for controlling the flow rate of the molten glass in the processing apparatus by the amount of electric power at the time of energization,
Wherein the amount of electric power is an amount of electric power capable of controlling the flow rate of the molten glass and is equal to or larger than a target amount of electric power that can not control the flow rate below the amount of electric power and in which the temperature of the molten glass is a temperature The amount of heat radiation from the processing apparatus to the outside is adjusted.

A processing device for processing the molten glass,
An energizing device for energizing the processing device by heating the molten glass so that the temperature of the molten glass in the processing device is in a range suitable for the processing,
And a control device for controlling the flow rate of the molten glass in the processing apparatus by the amount of current at the time of energization,
Wherein the amount of heat released from the processing apparatus to the outside is adjusted so that the amount of current capable of controlling the flow rate of the molten glass becomes equal to or larger than a target amount of current that can not control the flow rate below the amount of the current.