KR101730743B1 - Method and apparatus for making glass sheet - Google Patents

Method and apparatus for making glass sheet Download PDF

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Publication number
KR101730743B1
KR101730743B1 KR1020157001898A KR20157001898A KR101730743B1 KR 101730743 B1 KR101730743 B1 KR 101730743B1 KR 1020157001898 A KR1020157001898 A KR 1020157001898A KR 20157001898 A KR20157001898 A KR 20157001898A KR 101730743 B1 KR101730743 B1 KR 101730743B1
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South Korea
Prior art keywords
molten glass
glass
oxygen
amount
vapor phase
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KR1020157001898A
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Korean (ko)
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KR20150092736A (en
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고스케 사이토
히토시 ?코
히토시 ?┙?
신고 후지모토
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아반스트레이트 가부시키가이샤
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    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B5/00—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture
    • C03B5/16—Special features of the melting process; Auxiliary means specially adapted for glass-melting furnaces
    • C03B5/225—Refining
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B5/00—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture
    • C03B5/16—Special features of the melting process; Auxiliary means specially adapted for glass-melting furnaces
    • C03B5/225—Refining
    • C03B5/2252—Refining under reduced pressure, e.g. with vacuum refiners
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B5/00—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture
    • C03B5/16—Special features of the melting process; Auxiliary means specially adapted for glass-melting furnaces
    • C03B5/24—Automatically regulating the melting process
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B5/00—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture
    • C03B5/16—Special features of the melting process; Auxiliary means specially adapted for glass-melting furnaces
    • C03B5/167—Means for preventing damage to equipment, e.g. by molten glass, hot gases, batches
    • C03B5/1672—Use of materials therefor
    • C03B5/1675—Platinum group metals
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P40/00—Technologies relating to the processing of minerals
    • Y02P40/50—Glass production, e.g. reusing waste heat during processing or shaping
    • Y02P40/57—Improving the yield, e-g- reduction of reject rates

Abstract

The present invention includes a step of treating a molten glass containing a refining agent which releases oxygen by a reduction reaction using a treatment apparatus in which at least a part of the inner wall is made of a material containing a platinum group metal. Further, in the step of processing the molten glass, the amount of oxygen released from the molten glass is adjusted in the vapor phase space formed by the inner wall of the processing apparatus and the surface of the molten glass so that oxygen in the vapor phase space Control the concentration. In addition, in the interior of the processing apparatus, the maximum position of the bubble discharge amount at which the amount of bubbles discharged into the vapor phase from the surface of the molten glass becomes maximum and the maximum temperature position of the temperature distribution in the flow direction of the molten glass in the molten glass, The maximum position of the bubble discharge amount is adjusted so as to be spaced apart in the flow direction of the bubble.

Description

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

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

Generally, the production of a glass substrate includes a step of forming a molten glass from a glass raw material, and then molding the molten glass into a glass substrate after a refining step, a stirring step, or a homogenizing step.

In any of the processing apparatuses performing the above processes, it is necessary to use a material suitable for the member in contact with the molten glass in accordance with the temperature of the molten glass in contact with the member, the required quality of the glass substrate, and the like. That is, in order to mass-produce a glass substrate having a high quality from a high-temperature molten glass, it is desirable to consider that foreign matter or the like which is a defective factor of the glass substrate is not mixed into the molten glass from any glass processing apparatus that manufactures the glass substrate. For example, since the molten glass between the generation of the molten glass and the supply of the molten glass to the forming step is in a very high-temperature state, the processing apparatus for performing the respective processes such as melting, refining, A member containing a metal (e.g., platinum) is used (see, for example, Patent Document 1).

The above-mentioned process includes a refining process for removing minute bubbles contained in the molten glass. In a glass substrate used for a panel display such as a liquid crystal display or a plasma display or a flat panel display (FPD), defects due to bubbles remaining in the molten glass must be eliminated.

For this reason, a cleaning process is performed in the production of a panel display or a glass substrate for FPD. The refining is performed by passing molten glass containing a refining agent through the refining tube main body while heating the refining tube main body, and removing bubbles in the molten glass by an oxidation-reduction reaction of the refining agent.

More specifically, a cleaning agent that releases oxygen by a reduction reaction is used, and the temperature of the molten glass that has been roughly dissolved is further increased in the cleaning tube to release oxygen by reduction of the cleaning agent, And then the temperature is lowered so that the remaining oxygen that has not been completely defoamed is used for oxidation of the reduced refining agent to be absorbed in the molten glass. Also, a cleaning pipe for performing a cleaning process at a high temperature is also a member containing a platinum group metal (for example, platinum) having high heat resistance.

Japanese Patent Application Laid-Open No. 2010-111533

The cleaning process is a process in which the temperature of the molten glass is highest during the period from the dissolving process to the forming process, and the cleaning tube for performing the cleaning process is heated to an extremely high temperature in order to heat the molten glass. Then, the platinum group metal used in the purifying tube is oxidized by oxygen generated by the reduction of the refining agent in the molten glass, and volatilized as an oxide. On the other hand, the oxides of the platinum group metals are reduced at the locally lowered temperature of the purifying tube, and the reduced platinum group metals coalesce and adhere to the inner wall surface of the purifying tube. If a part of the platinum group metal attached to the inner wall surface is mixed into the molten glass as a foreign substance, the quality of the glass substrate may deteriorate. Particularly, the cleaning process is a process in which the temperature of the molten glass is maximized during the period from the dissolving process to the forming process, and therefore, it is heated to an extremely high temperature in the cleaning pipe which mainly performs the cleaning process. As a result, the volatilization of the platinum group metal in the purifying tube is active, and it is particularly desired to reduce the volatilization and agglomeration of the platinum group metal.

SUMMARY OF THE INVENTION An object of the present invention is to reduce the volatilization of the platinum group metal used in the glass processing apparatus in the step of processing the molten glass before molding the glass substrate and thereby to prevent the incorporation of foreign matter into the molten glass A method of manufacturing a substrate, and a glass substrate manufacturing apparatus.

The glass substrate manufacturing method and the glass substrate manufacturing apparatus of the present invention include the following modes.

(Form 1)

Comprising the step of treating a molten glass containing a refining agent which releases oxygen by a reduction reaction using a treatment apparatus wherein at least a part of the inner wall is made of a material containing a platinum group metal,

In the step of processing the molten glass,

The oxygen concentration in the vapor phase space is controlled so as to suppress the volatilization of the platinum group metal by adjusting the amount of oxygen released from the molten glass in the vapor phase space formed by the inner wall of the processing apparatus and the surface of the molten glass Wherein the glass substrate is a glass substrate.

(Form 2)

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

When treating a molten glass containing a refining agent that releases oxygen by a reduction reaction,

Wherein a molten glass is supplied to the upper part of the surface of the molten glass so as to form a vapor phase space in a processing apparatus in which at least a part of the inner wall is made of a material containing a platinum group metal,

Wherein the oxygen concentration in the vapor phase space is controlled so as to suppress the volatilization of the platinum group metal by adjusting the amount of oxygen released from the molten glass.

(Form 3)

Wherein the glass substrate contains 0.01 mol% to 0.3 mol% of tin oxide,

And the amount of oxygen released from the molten glass is adjusted according to the content of the tin oxide.

(Mode 4)

The method of manufacturing a glass substrate according to any one of 1 to 3, wherein the oxygen concentration is controlled by adjusting an amount of oxygen discharged from the vapor phase space to the outside of the processing apparatus.

(Mode 5)

The method of manufacturing a glass substrate according to any one of modes 1 to 4, wherein a gas whose supply amount is adjusted is supplied to the vapor phase space so that the oxygen concentration is within a predetermined range.

(Form 6)

The molten glass is allowed to flow in the direction along the surface of the molten glass in contact with the vapor phase space in the processing apparatus,

The amount of the oxygen released varies according to the position of the molten glass in the flow direction,

And adjusting the distribution of the oxygen concentration in the flow direction of the molten glass in the vapor phase space so as to suppress the volatilization of the platinum group metal by adjusting the distribution of the oxygen emission amount at the position in the flow direction of the molten glass, A method for manufacturing a glass substrate according to any one of the first to fifth aspects.

(Form 7)

The temperature of the processing apparatus changes in accordance with the position in the flow direction of the molten glass,

The distribution of the amount of oxygen emission is predicted using a computer simulation,

Wherein the processing conditions are determined using the computer simulation so that the position at which the amount of oxygen emission in the flow direction of the molten glass becomes maximum is spaced apart from a position at which the temperature of the processing apparatus becomes the highest. / RTI >

(Form 8)

The molten glass is allowed to flow in the direction along the surface of the molten glass in contact with the vapor phase space in the processing apparatus,

The temperature of the inner wall in contact with the vapor phase space of the processing apparatus has a temperature distribution along the flow direction of the molten glass, and in the processing of the molten glass, the discharge amount of the bubbles discharged from the surface of the molten glass to the vapor phase becomes the maximum Wherein the bubble discharge maximum position is adjusted so that the maximum bubble discharge maximum position in the flow direction of the molten glass and the maximum temperature position of the temperature distribution in the flow direction of the molten glass are spaced apart in the flow direction of the molten glass A method for manufacturing a glass substrate according to any one of claims 1 to 7.

(Mode 9)

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

And a step of melting the raw material of the glass to produce a molten glass,

And a refining agent which releases oxygen by a reduction reaction,

In the step of processing the molten glass,

Wherein a molten glass is supplied to the upper portion of the surface of the molten glass so as to form a vapor phase space inside the processing apparatus wherein at least a part of the inner wall is made of a material containing a platinum group metal, And flows in a direction along a surface in contact with the vapor space,

The temperature of the inner wall of the processing apparatus in contact with the vapor phase space has a temperature distribution along the flow direction of the molten glass,

In the processing direction of the molten glass, a maximum position of the bubble discharge amount in the flow direction of the molten glass in which the discharge amount of the bubbles released into the vapor phase space from the surface of the molten glass in contact with the vapor phase is maximized, Is adjusted so that the maximum temperature position of the temperature distribution of the molten glass is spaced apart in the flow direction of the molten glass.

(Mode 10)

Wherein the processing apparatus includes at least a cleaning tube for defoaming at least the molten glass, wherein at least a part of the inner wall is made of a material containing a platinum group metal,

The method of producing a glass substrate according to form 8 or 9, wherein the step of treating the molten glass is a fining step including a defoaming step of defoaming the molten glass in the purifying tube.

(Mode 11)

The bubble emission maximum position is predicted using a computer simulation,

And the processing conditions are determined using the computer simulation so that the maximum bubble emission amount position is spaced apart from the maximum temperature position in the flow direction of the molten glass.

(Form 12)

The method of manufacturing a glass substrate according to any one of modes 8 to 11, wherein adjustment of the maximum bubble emission amount position is performed by adjusting at least one of a temperature distribution of the molten glass and a flow rate of the molten glass.

(Form 13)

The method of manufacturing a glass substrate according to any one of Forms 8 to 12, wherein the maximum bubble emission amount position is located on the downstream side of the flow of the molten glass with respect to the maximum temperature position.

(Form 14)

Wherein the processing apparatus includes at least a cleaning tube for defoaming at least the molten glass, wherein at least a part of the inner wall is made of a material containing a platinum group metal,

Wherein the purifying tube is provided with an exhaust pipe communicating with the atmosphere in the vapor phase space and the outside of the processing apparatus,

The method for manufacturing a glass substrate according to any one of Forms 8 to 13, wherein an arrangement position of the exhaust pipe in the flow direction of the molten glass is between the maximum bubble emission amount position and the maximum temperature position.

(Form 15)

Wherein the processing apparatus includes at least a cleaning tube for defoaming at least the molten glass, wherein at least a part of the inner wall is made of a material containing a platinum group metal,

Wherein the purifying pipe is provided with an exhaust pipe that communicates with the atmosphere outside the vapor-phase space and the purifying pipe,

The bubble discharge maximum position and the position of the exhaust pipe in the flow direction of the molten glass are determined in accordance with Forms 8 to 14 To the glass substrate.

(Form 16)

Wherein a flange member extending to the outside of the processing apparatus is provided on an outer periphery of the processing apparatus and a position of the flange member in the flow direction of the molten glass is set to a region between the maximum position of the bubble emission amount and the position of the exhaust pipe Is in a region other than the above-described region.

(Mode 17)

Wherein the maximum temperature position of the temperature distribution, the position of the exhaust pipe, and the maximum bubble emission amount position are determined from the upstream side in the flow direction of the molten glass to the maximum temperature position, the placement position of the exhaust pipe, Wherein the glass substrate is placed in the following order.

(Form 18)

The processing apparatus is provided with an exhaust pipe communicating with the atmosphere outside the vapor phase space and the processing apparatus,

The method for producing a glass substrate according to any one of Forms 8 to 13, wherein the maximum bubble emission amount position and the position of the exhaust pipe in the flow direction of the molten glass are the same in the flow direction of the molten glass.

(Form 19)

An apparatus for producing a glass substrate for processing molten glass using a processing apparatus for processing molten glass,

Wherein at least a part of the inner wall is made of a material containing a platinum group metal and a molten glass containing a refining agent for releasing oxygen by reduction reaction is supplied to the molten glass and a vapor phase space is formed on the surface of the molten glass [0001]

And a control device configured to adjust the amount of oxygen released from the molten glass and adjust the amount of oxygen discharged from the vapor phase space so that the oxygen concentration in the gas phase becomes a predetermined range, Substrate manufacturing apparatus.

(Form 20)

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

A melting tank for melting the glass raw material to produce a molten glass;

Wherein at least a part of the inner wall is made of a material containing a platinum group metal and a molten glass containing a refining agent for releasing oxygen by a reduction reaction is supplied to the molten glass, And the temperature of the inner wall in contact with the vapor space has a temperature distribution along the flow direction of the molten glass, wherein the molten glass has a temperature distribution along the surface of the molten glass,

The maximum position of the bubble discharge amount in the flow direction of the molten glass in which the amount of bubbles discharged from the surface of the molten glass into the vapor phase is maximized in the processing of the molten glass and the temperature distribution in the flow direction of the molten glass Wherein the maximum position of the bubble discharge amount is adjusted so that the maximum temperature position of the molten glass is spaced apart in the flow direction of the molten glass.

(Form 21)

The apparatus for manufacturing a glass substrate according to Aspect 19 or 20, wherein the processing apparatus includes a purifying tube for defoaming the molten glass.

(Form 22)

Wherein the maximum temperature of the molten glass flowing in the inside of the processing apparatus is 1630 캜 to 1750 캜, or the glass substrate producing apparatus according to any one of the nineteenth to twenty-ninth aspects.

(Form 23)

The glass substrate manufacturing method according to any one of the above formulas 1 to 18 and 22, or the glass substrate producing apparatus according to any one of the 19 to 22, wherein the content of the tin oxide in the glass substrate is 0.01 mol% to 0.3 mol%.

(Form 24)

The vapor phase pressure of the platinum group metal in the gas phase is 0.1 Pa to 15 Pa. The method for producing a glass substrate according to any one of form 1 to 18, 22 and 23, or the glass substrate producing apparatus according to any one of form 19 to 23.

(Form 25)

The aggregates formed by the agglomeration of the oxides produced by the volatilization of the platinum group metals (hereinafter referred to as agglomerates of the platinum group metals) may be any one of Forms 1 to 24, for example having an aspect ratio of 100 or more to the minimum length of the maximum length Or a glass substrate manufacturing apparatus according to any one of the nineteenth to twenty-fourth aspects.

Further, for example, the maximum length of the agglomerate 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 substance obtained by photographing the aggregate of the platinum group metal, and the minimum length is the length of the shortest side of the circumscribed rectangle .

Alternatively, aggregates produced by agglomeration of volatiles of the platinum group metal may have an aspect ratio of 100 or more with respect to the minimum length of the maximum length, and the maximum length of agglomerates of the platinum group metal is 100 탆 or more, preferably 100 탆 to 300 탆 Can be determined.

(Form 26)

The glass substrate manufacturing method according to any one of the first to twenty-first aspects, wherein the glass substrate is a glass substrate for display, or the glass substrate producing apparatus according to any one of the nineteenth to twenty-fifth aspects.

Further, the glass substrate is suitable for a glass substrate for an oxide semiconductor display or a glass substrate for an LTPS display.

According to the glass substrate manufacturing method and the glass substrate manufacturing apparatus of the above-described forms, it is possible to suppress the incorporation of foreign matter into the molten glass by suppressing the volatilization of the platinum group metal in the processing step of the molten glass, for example, have.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a flow chart showing a manufacturing method of a glass substrate. Fig.
2 is a schematic diagram showing a configuration of a glass substrate manufacturing apparatus.
Fig. 3 is a schematic view of the cleaning tube of the first embodiment used in the manufacturing apparatus of Fig. 2;
Fig. 4 is a vertical cross-sectional view of the clarifying tube in the longitudinal direction of the first embodiment. Fig.
5 is a diagram showing the relationship between the position in the longitudinal direction of the purifying pipe of the first embodiment, the temperature at the upper end of the purifying pipe 120, and the oxygen emission amount.
6 is an external view of a cleaning tube according to the second embodiment.
Fig. 7 is a view showing the cross section of the finishing tube according to the second embodiment and the temperature distribution of the finishing tube. Fig.
Fig. 8 is a diagram showing the results of Experimental Example 1. Fig.

An embodiment of a glass substrate manufacturing method and a glass processing apparatus according to the present invention will be described with reference to the drawings. In this specification, suppressing the introduction of foreign matter into the molten glass by the adjustment of the oxygen concentration or the like is to reduce the amount of foreign matter mixed into the molten glass as compared with the case where the above adjustment is not performed, But the present invention is not limited to the case where the amount of foreign matter mixed into the molten glass is set to zero.

In the present specification, the upper part of the liquid surface refers to the upper portion in the vertical direction with respect to the liquid surface.

In the present specification, the upstream side of the molten glass flowing from the melting tank toward the molding apparatus refers to the side of the melting tank which forms the molten glass with respect to the noted position. Further, the downstream side of the molten glass refers to the side of the molding apparatus with respect to the noted position.

In this specification, the inside of the processing apparatus refers to a space surrounded by the inner wall.

The foreign substance by the aggregate of the platinum group metal means, for example, an elongated linear shape in one direction and an aspect ratio of more than 100, which is the ratio to the minimum length of the maximum length. 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 foreign substance obtained by photographing the aggregate of the platinum group metal, and the minimum length is the length of the shortest side of the circumscribed rectangle.

(Overview of Manufacturing Method of Glass Substrate)

Fig. 1 is a diagram showing an example of a process of a glass substrate manufacturing method according to the present embodiment. The manufacturing method of the glass substrate mainly has a melting step (ST1), a clarifying step (ST2), a stirring step (ST3), a molding step (ST4), a slow cooling step (ST5) and a cutting step (ST6).

In the melting step (ST1), the glass raw material is heated to produce a molten glass. The heating of the molten glass can be performed by energization heating in which the molten glass is heated by heating the molten glass by flowing electricity. In addition, the glass raw material may be dissolved by auxiliary heating by the flame of the burner.

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 viewpoint of environmental load reduction, it is preferable to use tin oxide as the fining agent.

In the refining step (ST2), the molten glass is heated to generate bubbles containing oxygen, CO 2 or SO 2 contained in the molten glass. This bubble absorbs the oxygen generated by the reduction reaction of the cleaning agent to expand (grow) the diameter of the bubble, float on the liquid surface of the molten glass, that is, on the free surface of the molten glass and the bubble ruptures and disappears, . Thereafter, in the refining step, the reducing material obtained by the reducing reaction of the refining agent performs the oxidation reaction by lowering the temperature of the molten glass. As a result, gas components such as oxygen in the bubbles remaining in the molten glass are reabsorbed into the molten glass, the diameter of the remaining bubbles is reduced, and the bubbles disappear. The oxidation reaction and the reduction reaction by the refining agent are performed by controlling the temperature of the molten glass.

In the refining step, a vacuum degassing method in which the diameter of the bubbles present in the molten glass is expanded in a reduced-pressure atmosphere and defoamed may be used. The vacuum degassing method is effective in that no refining agent is used. However, the vacuum degassing system complicates and increases the size of the apparatus. For this reason, it is preferable to employ a refining method that uses a refining agent and raises the temperature of the molten glass.

In the stirring step (ST3), the glass component is homogenized by stirring the molten glass using an agitator. As a result, unevenness in the composition of the glass, which is a cause of spoilage, can be reduced.

The molding step (ST4) and the slow cooling step (ST5) are performed in the molding apparatus.

In the molding step (ST4), the molten glass is formed into a sheet glass to form a sheet glass flow. For forming, an overflow down-draw method is used.

In the slow cooling step (ST5), 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 (ST6), the sheet glass after the slow cooling is cut to a predetermined length to obtain a plate-like glass substrate. The cut glass substrate is also cut to a predetermined size to produce a glass substrate of a desired size.

(Glass substrate manufacturing apparatus)

Fig. 2 is a schematic view of a glass substrate producing apparatus for performing the dissolving step (ST1) to cutting step (ST7) in the present embodiment. As shown in Fig. 2, the glass substrate producing apparatus has a melting apparatus 100, a molding apparatus 200, and a cutting apparatus 300 mainly. The melting apparatus 100 has a melting vessel 101, a clarifying tube 120, a stirring vessel 103, transfer tubes 104 and 105, and a glass tube 106.

The melting tank 101 shown in Fig. 2 is provided with a heating means such as a burner (not shown). A glass raw material to which a refining agent is added is introduced into the melting tank, and a dissolution step (ST1) is performed. The molten glass melted in the melting tank 101 at a high temperature (for example, 1500 占 폚 to 1600 占 폚) is supplied to the purifying pipe 120 through the transfer pipe 104. Further, in the melting tank 101, the molten glass between the electrodes may be heated by conduction by flowing a current between at least one pair of electrodes, and additionally, a flame by the burner is applied in addition to energization heating, .

In the cleaning tube 120, the temperature of the molten glass MG is adjusted, and the refining step (ST2) of the molten glass is performed using the redox reaction of the refining agent.

More specifically, the molten glass obtained in the melting tank 101 flows into the purifying pipe 120 from the melting tank 101 through the transfer pipe 104. The purifying tube 120, the transfer tubes 104 and 105, and the glass tube 106 are pipes made of a platinum group metal. A heating means is provided in the cleaning tube 120 in the same manner as the melting vessel 101. At least the transfer tube 104 is also provided with a heating means. In the refining step ST2, the molten glass is refined by raising the temperature of the molten glass. For example, the temperature of the molten glass in the cleaning tube 120 is 1600 캜 to 1720 캜. The refined molten glass in the purifying pipe 120 flows from the purifying pipe 120 through the transfer pipe 105 and flows into the agitation device 103. The molten glass is cooled when it passes through the transfer pipe (105). As described above, oxygen is released by the reduction reaction of the cleaning agent, and the released oxygen is absorbed into the bubbles contained in the molten glass. Bubbles that absorb oxygen and increase in bubble diameter float on the surface (liquid level) of the molten glass, and bubbles rupture and disappear. Subsequently, the temperature of the molten glass is lowered. Thereby, the reduced refining agent causes the oxidation reaction so that the molten glass absorbs the oxygen remaining in the molten glass.

The molten glass after refining is supplied to the stirring tank 103 through the transfer pipe 105.

In the stirring tank 103, the molten glass is stirred by the stirrer 103a and the stirring step (ST3) is performed. For example, in the stirring apparatus 103, the temperature of the molten glass is 1250 캜 to 1450 캜. For example, in the stirring apparatus 103, the viscosity of the molten glass is 500 poise to 1,300 poise. The molten glass stirred in the stirring tank 103 is supplied to the molding apparatus 200 through the glass supply pipe 106. When the molten glass passes through the transfer pipe 106, the molten glass is cooled so as to have a viscosity suitable for molding the molten glass. For example, the molten glass is cooled to 1100 to 1300 ° C. In the molding apparatus 200, the sheet glass is formed from the molten glass by the overflow down-draw method (molding step ST4) and slowly cooled (slow cooling step ST5).

In the cutting apparatus 300, a plate-like glass substrate cut out from the sheet glass is formed (cutting step ST6).

The purifying pipe 120, the stirring tank 103, the transfer pipes 104 and 105, and the glass supply pipe 106 are made of a material containing at least a part of the inner wall of the glass material. More preferably, the purifying tube 120, the stirring tank 103, the transfer tubes 104 and 105, and the glass supply tube 106 are pipes made of a platinum group metal. In this specification, the term " platinum group metal " means a metal containing 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 refers to 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.

(Application example of glass substrate)

When the aggregate of the platinum group metal on the surface of the glass substrate is detached from the surface of the glass substrate in the panel manufacturing process using the glass substrate, the portion of the separated surface is recessed, and the thin film formed on the glass substrate is uniformly formed There is a problem that display defects are caused on the screen. Further, when the aggregate of the platinum group metal is present in the glass substrate, deformation occurs due to a 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 suitable for manufacturing a glass substrate for a display in which a demand for display defects on the screen is strict. Particularly, the present embodiment provides a glass substrate for an oxide semiconductor display using oxide semiconductors such as IGZO (indium, gallium, zinc, oxygen) or the like and an LTPS (low temperature polysilicon) It is suitable for a high-precision display glass substrate such as a glass substrate for an LTPS display used.

As described above, the glass substrate produced by the glass substrate manufacturing method of the present embodiment is a glass substrate for a panel display such as a liquid crystal display, a plasma display, an organic EL display and the like requiring a very small content of alkali metal oxide, And is suitable for a glass substrate for a display (FPD). It is also suitable for a glass substrate for an oxide semiconductor display or a glass substrate for an LTPS display. It is also suitable as a cover glass for protecting a display, a glass for a magnetic disk, and a glass substrate for a solar cell. As a glass substrate for a panel display or a flat panel display, an alkali-free glass or an alkali-alkali-containing glass is used. Glass substrates for panel displays and flat panel displays have high viscosity at high temperatures. For example, the temperature of the molten glass having a viscosity of 10 2 5 poise is 1500 ° C or higher.

As the glass substrate for a display, the number of agglomerates of the platinum group metal in the glass substrate is preferably 1,000 pieces / m 3 or less, more preferably 100 pieces / m 3 or less, and still more preferably 50 pieces / m 3 or less. The number of bubbles in the glass substrate is preferably 1000 pieces / m 3 or less, more preferably 200 pieces / m 3 or less, and even more preferably 50 pieces / m 3 or less. Thus, by reducing the number of platinum metal agglomerates and the number of bubbles in the glass substrate, the number of display defects on the display can be reduced, and the yield can be improved.

(Glass composition)

In the melting tank 101, the glass raw material is dissolved by a heating means (not shown) to produce molten glass. The glass raw material is prepared so as to obtain substantially the glass of the desired composition. As an example of the composition of the glass, the alkali-free glass is suitable as a glass substrate for a panel display or a flat panel display, SiO 2: 50 mass% to 70 mass%, Al 2 O 3: 10% by mass to 25% by weight, B 2 O 3: 0% by mass to 15% by weight, MgO: 0% by mass to 10% by mass, CaO: 0 mass% to 20 mass%, SrO: 0 mass% to 20 mass%, BaO: 0% by mass to 10% by mass Lt; / RTI > Here, the total content of MgO, CaO, SrO and BaO is 5% by mass to 30% by mass.

Alternatively, a glass substrate suitable for a glass substrate for an oxide semiconductor display and a glass substrate for an LTPS display comprises 55 mass% to 70 mass% SiO 2 , 15 mass% to 25 mass% Al 2 O 3 , B 2 O 3 : 0 0 to 10 mass% of MgO, 0 to 10 mass% of MgO, 0 to 20 mass% of CaO, 0 to 20 mass% of SrO and 0 to 10 mass% of BaO. Here, the total content of MgO, CaO, SrO and BaO is 5% by mass to 30% by mass. At this time, it is more preferable that the glass substrate contains 60% by mass to 70% by mass of SiO 2 and 3% by mass to 10% by mass of BaO.

As a glass substrate for a panel display or a flat panel display, an alkali-containing glass containing a trace amount of an alkali metal may be used in addition to the alkali-free glass. If the glass of the glass substrate is an alkali-free glass containing tin oxide or an alkali-containing alkali glass containing tin oxide, it is possible to use a platinum group metal, which is generated by volatilization of the platinum group metal used for the inner wall of the glass processing apparatus of this embodiment The effect of inhibiting the impurities of the metal agglomerates from being mixed in the molten glass becomes remarkable. The alkali-free glass or alkali-glass-containing glass has a higher glass viscosity than alkali glass. Since a large amount of tin oxide is reduced in the dissolving step by increasing the melting temperature in the dissolving step, the temperature of the molten glass in the refining step is increased to accelerate the reduction of the tin oxide and the viscosity of the molten glass is lowered . In addition, since tin oxide has a higher temperature for accelerating the reduction reaction than the abiic acid or antimony which has been used as a conventional refinisher, the temperature of the molten glass is raised to promote refinement. Therefore, the temperature of the inner wall of the refinement tube 120 is increased Needs to be. That is, in the case of producing a glass-free substrate of alkali-free glass containing tin oxide or a glass containing alkali tin oxide containing tin oxide, it is necessary to raise the temperature of the molten glass in the refining step, It is easy to occur.

Further, the alkali-free glass substrate is a glass substantially free of alkali metal oxides (Li 2 O, K 2 O and Na 2 O). Incidentally, the glass containing an alkali trace amount is a glass having an alkali metal oxide content (a total amount of Li 2 O, K 2 O and Na 2 O) of more than 0 and not more than 0.8 mol%. The alkali micro-content-containing glass contains, for example, from 0.1% by mass to 0.5% by mass of the alkali metal oxide, preferably from 0.2% by mass to 0.5% by mass, of the alkali metal oxide. Here, the alkali metal oxide is at least one selected from Li 2 O, Na 2 O and K 2 O. The total content of the alkali metal oxides may be less than 0.1% by mass. Even if the content of the alkali metal oxide in the glass substrate is 0 to 0.8 mol%, it is possible to suppress the incorporation of the aggregate of the platinum group metal into the molten glass as a foreign substance by the following method.

A glass substrate manufactured by the present embodiment, in addition to the above components, SnO 2 and 0.01 mass% to 1 mass% (preferably 0.01 mass% to 0.5 mass%), Fe 2 O 3 0% by mass to 0.2% by weight ( Preferably 0.01% by mass to 0.08% by mass). It is preferable that the glass substrate produced by this embodiment does not contain As 2 O 3 , Sb 2 O 3 and PbO, or substantially does not contain, in consideration of environmental load.

As the glass substrate manufactured in the present embodiment, a glass substrate having the following glass composition is also exemplified. Therefore, the glass raw materials are combined so that the following glass composition is contained in the glass substrate.

For example, in terms of mol%, 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 (RO is MgO, CaO, SrO and BaO), R ' 2 O 0 to 0.4 mol% (R' is the sum of Li 2 O, K 2 O and Na 2 O), and 0.01 to 0.4 mol% of SnO 2 . At this time, the glass substrate contains at least any 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 x 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. Generally, in a glass having a high temperature viscosity, it is necessary to raise the temperature of the molten glass in the refining step, and therefore volatilization of the platinum group metal is likely to occur. That is, when manufacturing a glass substrate having such a composition, the effect of the present embodiment described later, that is, the effect of suppressing the incorporation of platinum group metal aggregates into the molten glass as a foreign substance becomes remarkable. The high-temperature viscosity refers to a glass viscosity at a high temperature of the molten glass, and the high temperature referred to herein means, for example, 1300 ° C or higher.

The molten glass to be used in the present embodiment may be a glass composition having a viscosity of 10 2 5 poise and a temperature of 1500 to 1700 캜. Such a glass is a glass having a high temperature viscosity, and a glass having a high temperature viscosity generally needs to have a high molten glass temperature in a refining step, so that the volatilization of the platinum group metal is likely to occur. That is, even in the case of a glass composition having a high temperature viscosity, the effect of the present embodiment described later, that is, the effect of suppressing the incorporation of a platinum group metal aggregate into the molten glass as a foreign substance becomes remarkable.

The deformation point of the molten glass used in the present embodiment may be 650 ° C or higher, more preferably 660 ° C or higher, more preferably 690 ° C or higher, and particularly preferably 730 ° C or higher. In addition, high strain point glass, there is a tendency that the viscosity is increased 10 2 temperature of the molten glass in the 5 poise. In other words, the effect of the present embodiment described later, that is, the effect of suppressing the incorporation of platinum group metal aggregates into the molten glass as a foreign substance becomes more significant when the glass substrate having a high strain point is produced. Further, since a glass having a high strain point is used for a high-precision display, there is a strong demand for a problem that a platinum group metal aggregate is incorporated as a foreign substance. As a result, the glass substrate of a high strain point is more suitable for the present embodiment in which the aggregation of the platinum group metal can suppress foreign matter incorporation.

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 having a temperature of 1,500 ° C or higher, the above effect of the present embodiment becomes more remarkable and the viscosity 10 2. the temperature of the molten glass when the 5 poise, for example a 1500 ℃ to 1700 ℃, may be a 1550 ℃ to 1650 ℃.

When the content of the refining agent, for example, tin oxide, contained in the molten glass changes, the amount of oxygen released from the molten glass into the vapor phase also changes. From the viewpoint of suppressing the volatilization of the platinum group metal, it is preferable that the oxygen concentration in the vapor phase space is controlled (adjusted) in accordance with the content of tin oxide. Therefore, the content of tin oxide is limited to 0.01 to 0.3 mol%, preferably 0.03 to 0.2 mol, from the standpoint of suppressing volatilization of platinum or platinum alloy. If the content of tin oxide is large, secondary crystals are generated in the molten glass in the tin oxide, which is not preferable. If the content of tin oxide is too large, oxygen released from the molten glass to the vapor phase space increases, and the oxygen concentration in the vapor phase space rises too much, resulting in an increase in the volatilization amount of the platinum group metal from the processing apparatus . If the content of tin oxide is too small, bubble defoaming of the molten glass is not sufficient.

(Configuration of the Clarifying Tube of the First Embodiment)

Next, the configuration of the cleaning tube 120 according to the first embodiment will be described with reference to Figs. 3 and 4. Fig. Fig. 3 is a schematic view showing the construction of the cleaning tube 120 of the first embodiment, and Fig. 4 is a vertical sectional view in the longitudinal direction of the cleaning tube 120. Fig.

Electrodes 121a and 121b are provided on both outer peripheral surfaces of the cleaning tube 120 in the longitudinal direction of the cleaning tube 120. An exhaust pipe 127 is formed in the wall of the cleaning tube 120, Is installed. That is, the finishing step of the present embodiment is a step of processing a molten glass containing a refining agent that releases oxygen by a reduction reaction. In this refining step, at least a part of the inner wall is treated with a material containing a platinum group metal In the inside of the apparatus, molten glass is supplied so that a vapor phase space is formed on the surface of the molten glass. In the cleaning tube 120, the molten glass flows in the longitudinal direction of the cleaning tube 120.

Further, a heat insulating material (for example, refractory bricks, refractory heat insulating bricks and the like) not shown may be provided outside the purifying pipe 120.

The cleaning tubes 120 are formed of the platinum group metals of the electrodes 121a and 121b and the exhaust pipe 127.

In the present embodiment, the case where the cleaning tube 120 is made of a platinum group metal is 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 supply device 122. [ A voltage is applied between the electrodes 121a and 121b so that 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 main body of the cleaning tube 120 is heated to, for example, 1600 占 폚 to 1750 占 폚, more preferably 1630 占 폚 to 1750 占 폚, The maximum temperature of the glass is heated to a temperature suitable for defoaming, for example, from 1600 캜 to 1720 캜, and more preferably from 1620 캜 to 1720 캜.

In addition, by controlling the temperature of the molten glass by conduction heating, the viscosity of the molten glass can be controlled, thereby controlling the flow rate of the molten glass passing through the purifying tube 120.

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

The control device 123 controls the amount of current that the power supply 122 energizes the cleaning tube 120 and thereby controls the temperature and flow rate of the molten glass passing through the cleaning tube 120. The control device 123 is a computer including a CPU, a memory, and the like.

As shown in Figs. 3 and 4, the electrode 121a is provided with a purge gas supply unit 120a for supplying purge gas to the vapor space 120a above the surface (liquid level) of the molten glass in contact with the vapor phase space in the purifying tube 120, A gas supply pipe 124a may be provided. Likewise, the electrode 121b is provided with a purge gas supply pipe 124b for supplying purge gas to the vapor space 120a above the surface (liquid level) of the molten glass in contact with the vapor phase space in the purifying pipe 120 It is possible.

The purge gas supply pipe 124a is connected to the purge gas supply device 125a and is connected to the purge gas supply device 125a via the purge gas supply pipe 124a and the vapor phase space 120a ), The purge gas is supplied from the upstream side of the molten glass. Similarly, the purge gas supply pipe 124b is connected to the purge gas supply device 125b and is connected to the vapor phase space 120a in the purifying pipe 120 through the purge gas supply pipe 124b from the purge gas supply device 125b, The purge gas is supplied from the downstream side of the glass. Here, the upstream side and the downstream side refer to the upstream side and the downstream side with respect to the center position of the vapor space 120a in the direction in which the molten glass flows.

By adjusting the inner diameters of the purge gas supply pipes 124a and 124b, the amount of the purge gas supplied from the purge gas supply pipes 124a and 124b can be adjusted.

As the purge gas, a gas which is inert to platinum and a reactivity lower than oxygen with the platinum group metal can be used. Specifically, nitrogen (N 2 ), rare gas (for example, argon (Ar)), or the like can be used. In Fig. 4, nitrogen is exemplified as a purge gas.

The purge gas supply devices 125a and 125b are controlled by the control device 123 to adjust the supply amount and the supply pressure of the purge gas.

An exhaust pipe 127 is provided on the wall of the purifying pipe 120 in contact with the vapor space. The exhaust pipe 127 is provided at an upper portion of the vapor space 120a. It is preferable that the exhaust pipe 127 is provided at a position between the upstream side end portion and the downstream side end portion in the flowing direction of the molten glass in the cleaning tube 120. The exhaust pipe 127 may protrude outwardly from the outer wall surface of the purifying pipe 120 in a chimney shape. The exhaust pipe 127 communicates with the vapor space 120a (see FIG. 4) and the outer space of the purifying pipe 120.

An oxygen concentration meter 128 is provided in the exhaust pipe 127. The oxygen concentration meter 128 measures the amount of gas passing through the exhaust pipe 127 and the oxygen concentration, and outputs the measurement signal to the control device 123. The oxygen concentration meter 128 is not particularly limited, and a known oxygen concentration meter is used.

In the present embodiment, the amount of oxygen released from the molten glass is adjusted by adjusting one or a combination of the content of the refining agent, the temperature of the molten glass, the viscosity of the molten glass, the kind of the glass raw material and the temperature history of the molten glass Is being controlled. The control of the amount of oxygen to be released is carried out by adjusting at least one of the content of the cleaning agent as described below, the temperature and viscosity of the molten glass, the kind of the glass raw material, and the temperature history of the molten glass.

(Content of refining agent)

For example, when the content of the cleaning agent is increased, the amount of oxygen released into the vapor space 120a in the cleaning tube 120 increases. On the other hand, if the content of the refining agent is reduced, the amount of oxygen released from the molten glass can be reduced.

In addition, if the amount of the cleaning agent is too small, the bubbles remaining in the molten glass can not be sufficiently reduced. Therefore, the content of the refining agent is preferably 0.01 mol% to 0.3 mol%, preferably 0.03 mol% to 0.2 mol%, or 0.01 to 0.5 wt%, for example, in the case of tin oxide. That is, in the present embodiment, by adjusting the content of tin oxide in the glass substrate in the range of 0.01 mol% to 0.3 mol% and adjusting the oxygen concentration in the gas phase space, it is possible to reduce the bubbles caused by the refining agent and suppress the volatilization of the platinum group metal Compatible.

(Temperature and viscosity of the molten glass)

The temperature of the molten glass can be adjusted by the temperature of the cleaning tube 120. When the temperature of the molten glass is raised, the amount of oxygen released from the molten glass is increased by the reduction reaction of the refining agent. When the temperature of the molten glass is low, the amount of generated oxygen is small, and the purifying effect can not be sufficiently obtained. Further, when the temperature of the molten glass is low, the molten glass viscosity becomes large, and the rising speed of the bubbles is slowed down. As a result, the vapor phase space 120a does not emit the bubbles in the molten glass, so that refinement can not be performed sufficiently.

On the other hand, if the temperature of the cleaning tube 120 is increased to raise the temperature of the molten glass, a problem of volatilization of the platinum group metal occurs. Therefore, in order to maintain the generation of bubbles while suppressing the volatilization of the platinum group metal, the temperature of the cleaning tube 120 is controlled to be, for example, 1600 to 1750 占 폚. As a result, the maximum temperature of the molten glass in the cleaning tube 120 is 1630 캜 to 1750 캜, preferably 1650 캜 to 1750 캜. At this time, the minimum viscosity of the molten glass is 200 to 800 poise. That is, in this embodiment, by adjusting the maximum temperature of the purifying pipe in the purifying step in the range of 1600 ° C. to 1750 ° C. and adjusting the oxygen concentration in the gas phase space, it is possible to reduce bubbles caused by the purifying agent and suppress the volatilization of the platinum group metal Can be compatible.

(Kind of glass raw material)

The amount of oxygen contained in the molten glass varies depending on the amount of the oxide contained in the glass raw material. Therefore, the amount of oxygen released into the vapor space 120a in the cleaning tube 120 can be adjusted by adjusting the type and amount of the glass raw material, specifically, by adjusting the amount of the oxide contained in the glass raw material.

(Temperature history of the molten glass)

The reduction reaction of the refining agent occurs in the process (dissolution step) before the refining process, and oxygen may be released from the molten glass. Therefore, the amount of oxygen released from the molten glass in the previous process (dissolution step) The amount of oxygen released into the vapor space 120a in the pipe 120 changes. Thus, the amount of oxygen released into the vapor space 120a in the cleaning tube 120 can be adjusted by the dissolution temperature or the like in the dissolution tank 101. [ Concretely, the lower the temperature in the dissolving process, the less the reducing reaction of the cleaning agent in the dissolving step, and the smaller the amount of oxygen released from the molten glass in the dissolving step, so that the vapor phase space 120a ) Is increased. However, if the melting temperature in the melting step is too low, a problem arises that the glass raw material can not be sufficiently dissolved, and if the molten glass temperature in the melting step is too high, the reducing reaction of the fining agent is excessively increased, There arises a problem that the purifying effect of the above-mentioned method can not be sufficiently obtained. Thereby, for example, by adjusting the maximum temperature of the molten glass temperature in the melting process in the range of 1500 占 폚 to 1610 占 폚 and adjusting the oxygen concentration in the gas phase space in the purifying pipe 120, It is possible to suppress the volatilization of the platinum group metal constituting the wall of the cleaning tube 120.

Further, the amount of reduction of the refining agent changes depending on the heating rate of the molten glass after the melting step. Concretely, the reduction reaction of the cleaning agent is promoted as the heating rate of the molten glass after the melting step becomes higher. However, if the temperature raising rate is too high, the temperature of the transfer pipe 104 or the purifying pipe 120 becomes too high, and the temperature of the transfer pipe 104 or the purifying pipe 120 or the temperature of the transfer pipe 104 or the purifying pipe 120 There arises a problem that the volatilization of the platinum group metal is increased, and if the heating rate is too low, there arises a problem that the refining effect in the refining step can not be sufficiently obtained. Therefore, for example, when the temperature of the molten glass in the transfer pipe 104 is raised to 1,630 ° C or more, the rate of temperature rise of the molten glass in the transfer pipe is controlled within a range of 3 ° C / min to 20 ° C / min And adjusting the oxygen concentration in the vapor phase space in the cleaning tube 120 for raising the temperature of the molten glass to 1630 DEG C or higher at the heating rate can reduce both bubble reduction by the cleaning agent and volatilization inhibition of the platinum group metal have. More preferably, the temperature raising rate and the molten glass temperature are preferably adjusted within a range of raising the temperature of the molten glass to 1630 DEG C or higher at a temperature raising rate of 3 DEG C / min to 10 DEG C / min.

In order to suppress the volatilization of the platinum group metal, it is preferable to adjust the oxygen concentration in the vapor space 120a to 0 to 10%. When the oxygen concentration in the gas phase space 120a is 0%, the volatilization of the platinum group metal is suppressed, so that the oxygen concentration is preferably 0% from the viewpoint of suppressing the volatilization of the platinum group metal. However, in order to always keep the oxygen concentration in the vapor space 120a at 0%, there is a problem that the content of the fining agent is greatly reduced, and the cost is high. Therefore, in order to realize the purifying or the low cost and the suppression of the volatilization of the platinum group metal , And the oxygen concentration in the vapor space 120a is preferably controlled to be 0.01% or more. It is also preferable to adjust the oxygen concentration in the vapor space 120a to 10% or less. In order to achieve both the inhibition of volatilization of the platinum group metal and the reduction in the number of bubbles, the oxygen concentration is preferably adjusted to be in the range of 0.1% to 3.0%, more preferably 0.1% to 1.0% And more preferably in the range of 0.3% or more and 0.7% or less. Here, if the oxygen concentration in the vapor phase space becomes too small, the difference in oxygen concentration between the molten glass and the vapor phase becomes large, oxygen released from the molten glass into the vapor phase space 120a increases, and the molten glass is excessively reduced, Bubbles such as sulfur oxides and nitrogen may remain on the glass substrate. On the other hand, if the oxygen concentration is too large, the volatilization of the platinum group metal is promoted, and the amount of the deposited platinum group metal may increase. If the oxygen concentration in the vapor phase space is too large, the difference in oxygen concentration between the molten glass and the vapor phase becomes too small to release oxygen from the molten glass into the vapor phase space 120a. As a result, Is increased.

In the present embodiment, the distribution of the amount of oxygen released from the molten glass at the position in the longitudinal direction of the cleaning tube 120 can be adjusted by adjusting the temperature distribution of the molten glass, the flow rate of the molten glass, and the content of the cleaning agent, It is also possible to adjust the position in the flow direction of the molten glass (the maximum position of the oxygen emission amount) at which the amount of oxygen released into the vapor phase space from the liquid level (liquid level) of the molten glass in contact with the vapor phase becomes maximum. Thus, the distribution of the oxygen concentration in the vapor space 120a can be controlled.

In the present embodiment, the maximum oxygen release amount is adjusted so as to be spaced apart from the position (the highest temperature position) in the flow direction of the molten glass in which the temperature of the molten glass is the highest, in the flow direction of the molten glass.

Further, the volatilization of the platinum group metal is promoted as the temperature is higher. As a result, the highest temperature position is a temperature condition in which the platinum group metal is most susceptible to volatilization. Further, the more the oxygen content is large, the more the volatilization of the platinum group metal becomes active.

Therefore, by adjusting the maximum position of the oxygen release amount so that the maximum oxygen position and the maximum temperature position are spaced apart from each other in the flow direction of the molten glass, the air bubbles emitted from the surface (liquid level) The amount of oxygen flowing in the highest temperature position decreases. As compared with the case where the oxygen released by defoaming of the molten glass flows into the highest temperature position where the platinum group metal is actively volatilizing from the wall of the purifying tube 120 to promote the volatilization of the platinum group metal, The volatilization of the platinum group metal is reduced. Thus, the volatiles of the platinum group metal flocculate on the wall of the cleaning tube 120 to form agglomerates, and a part of the agglomerates can be separated as fine particles to prevent foreign matter from entering the molten glass. This point will be explained below.

5 is a diagram showing the relationship between the position in the longitudinal direction of the purifying pipe 120 (the position in the flow direction of the molten glass), the temperature at the upper end of the purifying pipe 120, and the oxygen emission amount. 5, the abscissa indicates the position in the flow direction of the molten glass, that is, the longitudinal position of the cleaning tube 120, the ordinate on the left side indicates the temperature of the cleaning tube 120, and the ordinate on the right side indicates the amount of oxygen emission .

The solid curve of FIG. 5 shows the relationship between the position in the longitudinal direction and the temperature of the cleaning tube 120. In the cleaning tube 120 of the present embodiment, since the electrodes 121a and 121b are flange-shaped and have a high heat radiation function, the temperature near both end portions of the cleaning tube 120 is likely to locally become low. Since the exhaust pipe 127 also protrudes from the purifying pipe 120, the temperature in the vicinity of the exhaust pipe 127 of the purifying pipe 120 is likely to locally lower. As a result, the temperature of the wall of the cleaning tube 120 varies depending on the position of the molten glass in the flow direction.

For example, the vicinity of both end portions of the cleaning tube 120 (i.e., the vicinity of the electrodes 121a and 121b) and the vicinity of the exhaust pipe 127 become low temperature regions at positions in the flow direction of the molten glass. On the other hand, an intermediate portion between the exhaust pipe 127 and the electrodes 121a and 121b becomes a high temperature region at a position in the flow direction of the molten glass. The minimum temperature in the temperature distribution of the cleaning tube 120 is, for example, 1500 占 폚 or higher by the energization heating of the cleaning tube 120 by the electrodes 121a and 121b.

Fig. 5 shows an example of the temperature distribution of the cleaning tube 120. Fig. In this temperature distribution, the position (maximum temperature position) in the longitudinal direction in which the temperature reaches the maximum temperature T max ° C is denoted by P.

Here, the maximum temperature position is not limited to the position P but has an allowable range around the position P. [ The permissible range of the maximum temperature position is preferably a temperature range within a range of (T max -20) DEG C to T max DEG C, more preferably a temperature range within a range of (T max -10) DEG C to T max DEG C , Particularly preferably (T max -5) C to T max ° C. Then, the highest temperature position having the allowable range is referred to as the highest temperature position range R. 5, the maximum temperature position range R is shown as a temperature range within the range of (T max -20) ° C to T max ° C.

On the other hand, the one-dot chain line in FIG. 5 shows the relationship between the position in the longitudinal direction and the oxygen emission amount. When the molten glass is heated in the purifying tube 120, oxygen is released into the molten glass by the reduction reaction of the purifying agent in the molten glass. This oxygen release occurs rapidly. The released oxygen is absorbed by the bubbles in the molten glass to enlarge the diameter of the bubbles (the bubbles grow), or the bubbles in the molten glass absorb the existing bubbles in the molten glass to enlarge the diameter of the bubbles ), And the float is started toward the surface (liquid level) of the molten glass in contact with the vapor space while overcoming the viscosity of the molten glass. The position A in the longitudinal direction of the cleaning tube 120 at which the amount of oxygen released from the surface (liquid level) of the molten glass becomes maximum is the maximum temperature position range R, (The direction of flow of the molten glass). Specifically, it is preferable that the maximum oxygen release amount position A is adjusted so as to be positioned on the downstream side of the flow of the molten glass with respect to the maximum temperature position range R.

Generally, the reduction reaction of the refining agent releasing oxygen is activated as the temperature of the molten glass becomes higher. As the temperature of the molten glass is higher and the viscosity of the molten glass is lowered, the rate of rise of the molten glass is accelerated. Further, the higher the temperature of the inner wall in contact with the molten glass is, the higher the temperature of the molten glass is, so that the release of the bubbles from the molten glass becomes more active. Therefore, in general, the oxygen release amount maximum position A and the maximum temperature position range R substantially coincide with each other. However, in the present embodiment, as described above, the oxygen release amount maximum position A is adjusted such that the maximum oxygen release amount position A is spaced apart from the maximum temperature position range R. [

In addition, the distribution of the oxygen emission amount and the oxygen emission amount can be obtained by computer simulation. For example, the upper and lower limits of the oxygen release amount and the distribution of the oxygen release amount are determined in advance by experiments and the like. The upper limit of the oxygen emission amount is set so as to suppress the increase of the oxygen concentration in the vapor phase space and the acceleration of the volatilization of the platinum group metal due to the increase of the oxygen emission amount and the diameter of the bubbles in the molten glass is not increased due to the decrease of the oxygen emission amount, The lower limit of the oxygen emission amount is set so that the speed does not increase and the defoaming effect is not low. Also, the distribution of the oxygen release amount suitable for suppressing the volatilization of the high-efficiency deaerating and platinum group metals is set between the upper limit and the lower limit. The computer simulation can be used to extract the purifying condition so that the distribution of the target oxygen release amount and the target oxygen release amount in which the oxygen release amount is located between the upper limit and the lower limit is realized. The refining conditions include, for example, one of the content of the refining agent, the temperature of the molten glass, the viscosity of the molten glass, the kind of the glass raw material, and the temperature history of the molten glass or a combination thereof.

In the computer simulation, for example, heat conduction simulation is performed by modeling energization heating of a cleaning tube 120, a heat insulator (not shown) provided around the cleaning tube 120, and a cleaning tube 120, and at the same time, By using the result of the calculation of the temperature and the temperature distribution, a reduction reaction in the molten glass is determined by determining the distribution of the amount of oxygen emission and the amount of emission of the refining agent by using the corresponding relationship between the temperature of the molten glass determined in advance and the amount of oxygen emission of the refining agent Simulation is also carried out to estimate the amount of oxygen released and its distribution by simulating the expansion of the diameter of the bubbles by simulating the expansion of the diameter of the bubbles by absorbing oxygen in the predetermined bubbles in the molten glass.

Heat conduction simulation is performed by modeling the conduction heating of the cleaning tube 120, the heat insulating material (not shown) provided around the cleaning tube 120, and the cleaning tube 120. Simultaneously, the temperature calculation value of the molten glass The oxidation-reduction reaction in the molten glass is simulated by generating bubbles of a predetermined size by determining the emission amount of oxygen of the fining agent by using the corresponding relationship between the temperature of the molten glass determined in advance and the emission amount of oxygen of the fining agent, It is possible to predict the oxygen release amount maximum position A by simulating the expansion of the diameter of the bubbles by simulating the expansion of the bubbles and the expansion of the diameter of the bubbles by absorbing the predetermined bubbles in the molten glass. In this case, the total amount of released oxygen can also be predicted. Such a simulation can be executed on a computer using a known simulation program or the like. Then, a computer simulation can be used to determine the fining conditions so that the maximum oxygen emission amount position A is spaced apart from the maximum temperature position range R and the flow direction of the molten glass.

Here, the maximum oxygen release amount position A can be controlled by adjusting at least one of the temperature distribution of the molten glass flowing in the purifying pipe 120, the flow rate of the molten glass, the content of the refining agent, and the kind thereof. The temperature distribution of the molten glass influences the amount of oxygen released from the refining agent and the release start position of oxygen, and further the rate of rise of bubbles in the molten glass. The temperature distribution of the molten glass can be adjusted, for example, by the heating amount of the cleaning tube 120 in the conduction heating of the heating electrode 121b or by adjusting the current distribution around the circumference of the cleaning tube 120 . The temperature distribution of the molten glass can be adjusted by, for example, adjusting the amount of heat radiation from the outer periphery of the cleaning tube 120 toward the outside. Adjustment of the amount of heat radiation is performed by adjusting the heat insulating properties (thermal conductivity and the like) and the thermal resistance (= (thickness of the heat insulating material) / thermal conductivity) of the heat insulating material surrounding the periphery of the cleaning tube 120. This adjustment parameter can be changed and the oxygen emission maximum position A can be adjusted using a computer simulation.

The flow velocity of the molten glass influences the distance from the release start position of oxygen in the molten glass to the release position of oxygen on the surface (liquid level) of the molten glass. The adjustment of the flow rate of the molten glass can be performed, for example, by adjusting the temperature (viscosity) of the molten glass in the vicinity of the outlet of the molten glass of the cleaning tube 120, It can be adjusted by the drawing amount of the glass. This adjustment parameter can be changed and the oxygen emission maximum position A can be adjusted using a computer simulation.

In actual production of the glass substrate, each value (conditioning condition) of the adjustment parameter when the maximum oxygen release amount A adjusted by the computer simulation becomes a desired position is used.

In the present embodiment, the purifying pipe 120 is provided with an exhaust pipe 127 that communicates with the atmosphere outside the vapor phase space 120a and the purifying pipe 120. It is preferable that the position of the exhaust pipe 127 in the flow direction of the molten glass be between the maximum oxygen emission amount position A and the maximum temperature position range R. [ By determining the position of the exhaust pipe 127 in this manner, oxygen in the bubbles discharged from the surface is discharged from the surface (liquid level) of the molten glass contacting the vapor space at a maximum oxygen- Most of the oxygen is discharged from the exhaust pipe 127 to the outside of the purifying pipe 120a before flowing into the maximum temperature position range R by the exhaust pipe 127. [ Therefore, it is less likely that oxygen in the bubbles discharged from the oxygen discharge maximum position A flows into the maximum temperature range R, and the volatilization of the platinum group metal in the maximum temperature range R can be reduced.

It is preferable that both the maximum oxygen release amount position A and the exhaust pipe 127 are on the same side with respect to the maximum temperature position range R (including the maximum temperature position P). That is, it is preferable that both the maximum oxygen release amount position A and the exhaust pipe 127 are both upstream of the maximum temperature position range R in the flow direction of the molten glass, or both are located downstream of the maximum temperature position range R. In this case, the possibility that oxygen in the bubbles discharged from the maximum oxygen release amount position A flows through the maximum temperature position range R is low, and the volatilization of the platinum group metal in the maximum temperature position range R can be reduced.

For example, it may be arranged from the upstream side of the molten glass to the maximum temperature position range R, the maximum oxygen emission amount position A, and the exhaust pipe 127 in this order. In this case, the oxygen released at the maximum oxygen emission amount position A flows in the direction of the exhaust pipe 127, so that the oxygen released at the maximum oxygen emission amount position A is supplied to the vapor space 120a near the maximum temperature position range R of the molten glass It is difficult to flow into a high temperature atmosphere.

In particular, it is preferable to arrange the molten glass in the order of the maximum temperature position range R, the position of the exhaust pipe 127, and the maximum oxygen release amount A from the upstream side of the molten glass.

The maximum position A of the oxygen emission amount and the position of the exhaust pipe 127 may be the same in the flow direction of the molten glass. The oxygen released from the surface (liquid level) of the molten glass at the maximum oxygen emission amount position A is shifted to the position of the exhaust pipe Can be discharged to the outside of the purifying pipe (120) via the opening (127). In this case, the oxygen emitted from the surface of the molten glass at the maximum oxygen emission amount position A does not diffuse into the vapor space 120a and flows toward the exhaust pipe 127 without flowing through the vapor space 120a. Owing to this, oxygen released from the surface (liquid level) of the molten glass at the maximum oxygen emission amount position A is rarely used for volatilization of the platinum group metal. The same position of the oxygen discharge maximum position A and the exhaust pipe 127 in the flow direction of the molten glass is set to be the same as the position of the exhaust pipe 127 in the flow direction of the molten glass 127) in the range of the dimension of the diameter of the pipe. When the allowable range of the maximum oxygen release amount A is determined with respect to the oxygen release maximum position A, the allowable range may be partially overlapped with the area within the dimension of the pipe diameter.

In this embodiment, a flange-shaped member (for example, electrodes 121a and 121b) extending to the outside of the purifying pipe 120 is provided on the outer periphery of the purifying pipe 120. It is preferable that the flange-shaped member is located in a region other than the region between the maximum oxygen emission amount position A and the position of the exhaust pipe 127 in the flow direction of the molten glass. That is, it is preferable that the flange-shaped member is located on the upstream side of the molten glass or the downstream side of the molten glass than the position of the exhaust pipe 127 at the maximum position A and the position of the exhaust pipe 127 Do. Since the amount of heat radiated from the flange-shaped member to the outside is large, the temperature in the vicinity of the portion where the flange-shaped member of the cleaning tube 120 is provided is locally lowered. In this case, the volatiles of the platinum group metal in the vapor space 120a pass through the vicinity of the flange-shaped member and are cooled and reduced, and the reduced platinum group metal may cohere to the inner wall surface of the cleaning tube 120. [ Therefore, it is preferable that no flange-shaped member is disposed in a region between the maximum oxygen emission amount position A and the position of the exhaust pipe 127.

In the present embodiment, the amount of oxygen discharged from the exhaust pipe 127 provided in the upper part of the vapor space 120a is adjusted.

The amount of oxygen discharged from the exhaust pipe 127 is calculated by measuring the oxygen concentration of the gas exhausted from the exhaust pipe 127 by the oxygen concentration meter 128 and measuring the total amount of the gas exhausted from the exhaust pipe 127 . The amount of oxygen to be discharged can be adjusted by adjusting the total amount of gas discharged from the exhaust pipe 127 in accordance with the oxygen concentration measured by the oxygen concentration meter 128.

For example, the exhaust pipe 127 can be provided with a suction device for suctioning the gas in the vapor space 120a, and the total amount of the gas discharged from the discharge pipe 127 can be adjusted by adjusting the output of the suction device. 4, when the purge gas is supplied to the vapor space 120a, the amount of the purge gas supplied to the vapor space 120a may be controlled by controlling the suction device.

In this embodiment, the amount of oxygen released from the molten glass is adjusted and the amount of oxygen discharged from the exhaust pipe 127 provided in the upper portion of the vapor space 120a is adjusted so that the oxygen in the vapor space 120a And the concentration is adjusted to be within a predetermined range. Thereby, the platinum group metal can be prevented from being oxidized and volatilized, and the precipitation amount of the platinum group metal due to the reduction of the volatile platinum group metal can be reduced. In the case of using tin oxide as the fining agent, as compared with the case of using As 2 O 3 and Sb 2 O 3 , since the temperature range where the tin oxide exhibits the refining effect is high and the volatilization of the platinum group metal becomes remarkable, The effect of this embodiment is particularly effective.

In this embodiment, purge gas is supplied from the purge gas supply pipe 124a and the purge gas supply pipe 124b to the vapor phase space 120a in the purifying pipe 120 to discharge the purge gas from the molten glass in the purifying pipe 120 It is possible to reduce the oxygen concentration in the vapor space 120a by discharging oxygen. At this time, the oxygen concentration in the vapor space 120a can be adjusted to a predetermined range by adjusting the supply amount of the purge gas in accordance with the oxygen concentration measured by the oxygen concentration meter 128. [ Thereby, the platinum group metal can be prevented from being oxidized and volatilized, and the precipitation amount of the platinum group metal due to the reduction of the volatile platinum group metal can be reduced.

In this embodiment, the amount of gas discharged from the exhaust pipe 127 is measured, the oxygen concentration is measured by the oxygen concentration meter 128, and the amount of oxygen discharged from the exhaust pipe 127 (= exhaust pipe 127 The supply amount of the purge gas is adjusted so that the total amount of discharged gas x oxygen concentration) becomes a predetermined range. That is, signals indicating the total exhaust amount from the exhaust pipe 127 measured by the oxygen concentration meter 128 and the oxygen concentration in the exhaust are output to the control device 123, and the control device 123 outputs the signal from the oxygen concentration meter 128 The purge gas supply devices 125a and 125b are controlled to adjust the supply amount and the supply pressure of the purge gas.

The amount of oxygen released from the molten glass in the purifying pipe 120 is adjusted so that the upstream side of the molten glass is larger than the downstream side in this embodiment. Therefore, the purge gas supplied from the upstream side of the molten glass, Is preferably larger than the purge gas supplied from the downstream side of the molten glass. That is, the amount of the purge gas supplied from the purge gas supply pipe 124a is preferably made larger than the amount of the purge gas supplied from the purge gas supply pipe 124b. The amount of the purge gas supplied from the purge gas supply pipe 124a is made larger than the amount of the purge gas supplied from the purge gas supply pipe 124b so that the oxygen emitted from the molten glass can be more efficiently diluted with the purge gas and discharged.

Further, a suction device for sucking the gas in the vapor space 120a may be provided in the exhaust pipe 127. The oxygen and purge gas in the vapor space 120a can be efficiently discharged by reducing the pressure of the side of the exhaust pipe 127 by the suction device (for example, reducing the pressure by about 10 Pa relative to the pressure in the vapor space 120a). In addition, the amount of the purge gas supplied to the vapor space 120a can be controlled by controlling the suction device.

(Configuration of the Clarifying Tube of the Second Embodiment)

Next, the construction of the cleaning tube 120 of the second embodiment will be described in detail. The refining apparatus also includes a refractory brick (not shown) surrounding the outer periphery of the exhaust pipe (vent pipe) 127, the electrodes 121a and 121b, and the purifying pipe 120 in addition to the purifying pipe 120 do. 6 is an external view showing mainly the purifying pipe 120. As shown in Fig. 7 is a cross-sectional view showing the inside of the purifying pipe 120 and an example of the temperature distribution of the purifying pipe.

An exhaust pipe (vent pipe) 127 and a pair of electrodes 121a and 121b are provided in the purifying pipe 120. [ In the inside of the purifying pipe 120, a fining process of a molten glass containing a purifying agent that releases oxygen by a reduction reaction is performed. In this refining step, molten glass is supplied to the upper part of the surface of the molten glass so that at least part of the inner wall of the refining tube 120 is made of a material containing a platinum group metal, ), The molten glass flows in the direction along the surface in contact with the vapor space of the molten glass, specifically, in the longitudinal direction of the purifying pipe 120. The vapor phase space is formed along the flow direction of the molten glass. At least a part of the inner wall surrounding the vapor space is made of a material containing a platinum group metal. In the present embodiment, the entire wall surrounding the vapor phase space is made of a material containing a platinum group metal.

An exhaust pipe (vent pipe) 127 is provided on the inner wall in contact with the vapor space in the middle of the direction in which the molten glass flows, and communicates the atmosphere outside the purifying pipe 120 with the atmosphere. The exhaust pipe (vent pipe) 127 is preferably formed of a platinum group metal, like the purifying pipe 120. A heating mechanism for heating the exhaust pipe (vent pipe) 127 may be provided in the exhaust pipe (vent pipe) 127 since the temperature of the exhaust pipe (vent pipe) 127 is easily lowered by the heat dissipating function.

The pair of electrodes 121a and 121b are flange-shaped electrode plates provided at both ends of the cleaning tube 120. [ The electrodes 121a and 121b flow current supplied from a power source (not shown) to the cleaning tube 120, and the cleaning tube 120 is energized and heated by this current. When the tin oxide is used as the fining agent, for example, the purifying tube 120 is heated so that the maximum temperature is from 1600 캜 to 1750 캜, more preferably from 1630 캜 to 1750 캜, Deg.] C to 1720 [deg.] C, more preferably 1620 [deg.] C to 1720 [deg.] C. By controlling the current flowing through the cleaning tube 120, the temperature of the molten glass flowing inside the cleaning tube 120 can be controlled. Thus, the molten glass passing through the inside of the purifying pipe 120 is heated and cleaned. The pair of electrodes 121a and 121b are provided on the cleaning tube 120, but the number of the electrodes is not particularly limited. The temperature of the inner wall in contact with the vapor phase space of the cleaning tube 120 by energization heating by the electrodes 121a and 121b is in the range of, for example, 1500 to 1750 占 폚.

In the inside of the cleaning tube 120, bubbles containing CO 2 or SO 2 contained in the molten glass are removed by redox reaction of a cleaning agent added to the molten glass, for example, tin oxide. Concretely, at first, the temperature of the molten glass is raised to reduce the fining agent, thereby generating bubbles of oxygen in the molten glass. Bubbles containing gaseous components such as CO 2 , N 2 and SO 2 contained in the molten glass absorb oxygen generated by the reduction reaction of the fining agent. The bubbles whose oxygen bubbles are enlarged in diameter by absorption of oxygen absorb the bubbles on the surface (liquid level) of the molten glass in contact with the vapor phase space to release the bubbles, that is, the bubbles rupture and disappear. The gas contained in the extinct bubble is discharged to the vapor phase space and discharged to the outside of the cleaning tube 120 via the exhaust pipe 127. Then, the temperature of the molten glass is lowered to oxidize the reduced refining agent. Thereby, the oxygen of the bubbles remaining in the molten glass is dissolved in the molten glass (absorbed). As a result, the remaining bubbles become small and disappear. Thus, the bubbles contained in the molten glass are removed by the redox reaction of the refining agent.

Although not shown, a refractory protective layer is provided on the outer wall surface of the cleaning tube 120. A refractory brick is further provided on the outside of the refractory protective layer. The refractory bricks are mounted on a base (not shown).

In this cleaning tube 120, the temperature of the wall of the cleaning tube 120 in contact with the vapor phase space has a temperature distribution along the flow direction of the molten glass. When the molten glass is defoamed, the maximum position of the bubble discharge amount in the flow direction of the molten glass in which the amount of the bubbles discharged from the surface (liquid level) of the molten glass in contact with the vapor space becomes maximum in the gas- The maximum bubble emission amount position is adjusted so that the maximum temperature position of the temperature distribution in the molten glass is spaced apart in the flow direction of the molten glass.

Further, the higher the temperature of the inner wall of the platinum group metal is, the more volatile is promoted. As a result, the highest temperature position is a temperature condition in which the platinum group metal is most susceptible to volatilization. Further, the more the oxygen content is large, the more the volatilization of the platinum group metal becomes active.

Therefore, by adjusting the maximum bubble emission amount position so that the maximum bubble emission amount position and the maximum temperature position are spaced apart in the flow direction of the molten glass, oxygen in the bubbles emitted from the surface (liquid level) of the molten glass at the maximum bubble emission amount position The flow rate at the highest temperature position is smaller. As compared with the case where the oxygen released by defoaming of the molten glass flows into the highest temperature position where the platinum group metal is actively volatilizing from the wall of the purifying tube 120 to thereby promote the volatilization of the platinum group metal, The volatilization of the platinum group metal is reduced. Thus, the volatiles of the platinum group metal flocculate on the wall of the cleaning tube 120 to form agglomerates, and a part of the agglomerates can be separated as fine particles to prevent foreign matter from entering the molten glass. This point will be explained below.

Fig. 7 is a diagram showing the positional relationship between the cross section of the cleaning tube 120 and the temperature distribution of the wall of the cleaning tube 120. Fig. The top of Fig. 7 is a cross-sectional view of the clarifying tube 120. Fig. 7 is a graph showing the temperature distribution of the inner wall in contact with the vapor-phase space of the cleaning tube 120. As shown in FIG. In the graph showing the temperature distribution of the inner wall in contact with the vapor space of the cleaning tube 120, the horizontal axis indicates the position in the flow direction of the molten glass, that is, the longitudinal position of the cleaning tube 120, Of the inner wall contacting the vapor space.

(Flange members) 121a and 121b having a flange shape in the cleaning tube 120 of the present embodiment have a high heat dissipation function. Therefore, the wall near both end portions of the cleaning tube 120 is prevented from being melted (The inner wall of the cleaning tube 120 in contact with the vapor space) along the glass flow direction (X direction: the longitudinal direction of the cleaning tube 120). Since the exhaust pipe 127 also protrudes from the purifying pipe 120, the inner wall of the purifying pipe 120 in contact with the vapor space in the vicinity of the exhaust pipe 127 is also surrounded by the surrounding inner wall along the X direction (The inner wall of the cleaning tube 120 that contacts the inner surface of the cleaning tube 120). As a result, the temperature of the inner wall of the cleaning tube 120 in contact with the vapor space has a temperature distribution along the X direction. The vicinity of both end portions of the cleaning tube 120, that is, the inner wall near the end portions of the pair of electrodes 121a and 121b and the wall near the exhaust pipe 127 become low temperature regions with low temperature in the X direction, 127 and the electrodes 121a, 121b becomes a high-temperature region having a high temperature in the X direction. The temperature in the temperature distribution of the inner wall becomes a high temperature, for example, 1500 占 폚 or more, by energizing heating of the cleaning tube 120 by the electrodes 121a and 121b even at the lowest temperature. As a result, the platinum group metal constituting the cleaning tube 120 volatilizes in the vapor space, and volatile substances of the platinum group metal exist. Fig. 7 shows an example of the temperature distribution. In this temperature distribution, the position in the X direction where the temperature becomes the maximum temperature T max ° C is denoted by P.

Here, the maximum temperature position of the temperature distribution is not limited to the position P but has an allowable range around the position P. [ The permissible range of the maximum temperature position is preferably a temperature range within a range of (T max -20) DEG C to T max DEG C, more preferably a temperature range within a range of (T max -10) DEG C to T max DEG C , Particularly preferably (T max -5) C to T max ° C. Then, the highest temperature position having the allowable range is referred to as the highest temperature position R.

On the other hand, the molten glass is heated in the purifying tube 120, and the purifying agent undergoes a reduction reaction to initiate the release of oxygen into the molten glass. This oxygen release occurs rapidly. The released oxygen is absorbed by the bubbles in the molten glass to enlarge (grow) the diameter of the bubbles, or becomes bubbles in the molten glass to absorb the existing bubbles in the molten glass to enlarge the diameter of the bubbles ) To overcome the viscosity of the molten glass and start floating toward the surface (liquid level) of the molten glass in contact with the vapor phase space. At this time, the maximum position A of the bubble discharge in the longitudinal direction of the cleaning tube 120 at which the amount of bubbles discharged from the surface (liquid level) of the molten glass becomes maximum is spaced apart from the maximum temperature position R in the X direction. Specifically, it is preferable that it is located on the downstream side of the flow of the molten glass with respect to the maximum temperature position R.

The bubble discharge maximum position A is thus adjusted such that the maximum bubble discharge position A is spaced apart from the maximum temperature position R. [

The maximum position A of the air bubble can be obtained by experiment, but it can also be obtained by computer simulation. In the case of computer simulation, a simulation of heat conduction is performed by modeling a heating source created by energization heating of a cleaning tube 120, a refractory brick not shown, a not shown refractory protection layer and a refractory brick At the same time, using the temperature calculation value of the molten glass as a result of this simulation, the amount of oxygen of the fining agent is determined by using the correspondence relation between the predetermined temperature of the molten glass and the amount of oxygen emission of the fining agent, Thereby simulating the redox reaction in the molten glass and simulating the expansion of the diameter of the expanded bubble by the expansion of the diameter of the bubble due to the absorption of oxygen by the predetermined bubble in the molten glass and the prediction of the maximum bubble emission amount A . In this case, the amount of bubbles to be emitted can also be predicted. Such a simulation can be executed on a computer using a known simulation program or the like. Then, a computer simulation can be used to determine the firing conditions so that the maximum bubble emission amount position A is spaced apart in the X direction from the maximum temperature position R. [

Here, it is preferable that the maximum position A of the bubble discharge is performed by adjusting at least one of the temperature distribution of the molten glass flowing in the purifying pipe 120 and the flow rate of the molten glass. The temperature distribution of the molten glass influences the amount of oxygen released from the refining agent and the release start position of oxygen, and further the rate of rise of bubbles in the molten glass. The temperature distribution of the molten glass can be adjusted, for example, by the heating amount of the cleaning tube 120 in the conduction heating of the heating electrode 121b or by adjusting the current distribution of the main phase of the cleaning tube 120 . The temperature distribution of the molten glass can be adjusted by, for example, adjusting the amount of heat radiation from the outer periphery of the cleaning tube 120 toward the outside. The adjustment of the amount of heat radiation is performed by adjusting the heat insulating properties (thermal conductivity) and the thermal resistance (= (thickness of the refractory protective layer or the refractory brick) / thermal conductivity) of the refractory protective layer or the refractory brick surrounding the periphery of the cleaning tube 120 Loses. This adjustment parameter can be changed, and the maximum bubble emission amount A can be adjusted using a computer simulation.

The flow velocity of the molten glass influences the distance from the oxygen release start position in the molten glass to the oxygen release position on the surface (liquid level) of the molten glass in contact with the vapor phase space. The flow rate of the molten glass can be adjusted by adjusting the temperature (viscosity) of the molten glass near the outlet of the molten glass of the cleaning tube 120 or the temperature of the molten glass Can be adjusted by the amount of drawing of This adjustment parameter can be changed, and the maximum bubble emission amount A can be adjusted using a computer simulation.

In actual production of the glass substrate, each value of the adjustment parameter (cleaning condition) when the maximum position A of the bubble emission amount adjusted by computer simulation becomes a desired position is used.

The exhaust pipe 127 communicating with the atmosphere outside the vapor-phase space and the purifying pipe 120 is provided in the purifying pipe 120. At this time, the arrangement position of the exhaust pipe 127 in the X direction is , It is preferable that the maximum bubble emission amount position A and the maximum temperature position R are set. By setting the position of the exhaust pipe 127 in this manner, oxygen in the bubbles emitted from the surface is bubbled by the airflow at a maximum position A of bubbles discharged from the surface of the molten glass in contact with the gaseous phase, Most of the oxygen is discharged from the exhaust pipe 127 to the outside of the purifying pipe 120a before the exhaust gas reaches the maximum position A. [ Therefore, the possibility that oxygen in the bubbles discharged from the maximum bubble emission amount position A flows to the maximum temperature position R is low, and the volatilization of the platinum group metal at the maximum temperature position R can be reduced.

It is preferable that the bubble discharge maximum position A and the position of the exhaust pipe 127 in the X direction are on the same side in the X direction with reference to the maximum temperature position R of the temperature distribution of the wall of the cleaning tube 120 . Even in this case, the possibility that oxygen in the bubbles discharged from the maximum bubble discharge amount position A flows to the maximum temperature position R is low, and the volatilization of the platinum group metal at the maximum temperature position R can be reduced.

The maximum temperature position R, the placement position of the exhaust pipe 127, and the maximum bubble discharge amount position A are set in the order of the maximum temperature position R, the placement position of the exhaust pipe 127, and the maximum bubble emission position A from the upstream side in the X direction .

In this embodiment, a flange-like member (flange member) including electrodes 121a and 121b extending to the outside of the purifying pipe 120 is provided on the outer periphery of the purifying pipe 120, It is preferable that the arrangement position in the direction is the area in the longitudinal direction other than the area between the maximum position A of the bubble discharge and the position where the exhaust pipe 127 is arranged. Since the flange-shaped member has a large amount of heat radiation to the outside of the exhaust pipe 127 due to its shape, the temperature is likely to locally lower in the vicinity of the inner wall of the cleaning pipe 120 where the flange-shaped member is installed. In this case, the volatiles of the platinum group metal in the vapor phase pass near the inner wall on which the flange-shaped member is provided, so that the volatiles are cooled and may cohere on the inner wall of the purifying pipe 120. Therefore, it is preferable that the arrangement position of the flange-shaped member is in a region other than the region between the maximum position A of the bubble discharge and the position of the exhaust pipe 127.

In the present embodiment, the maximum temperature position R, the position of the exhaust pipe 127, and the maximum bubble discharge amount position A are the maximum temperature position R from the upstream side in the X direction, the placement position of the exhaust pipe 127, A, the maximum position A of the bubble discharge and the position of the exhaust pipe 127 are located on the same side in the X direction (longitudinal direction of the purifying tube 120) with respect to the maximum temperature position R The maximum temperature position R, the position of the exhaust pipe 127, and the maximum bubble emission amount position A are not limited. For example, the molten glass may be positioned in the order from the upstream side in the X direction in which the molten glass flows to the highest temperature position R, the maximum bubble discharge amount position A, and the position of the exhaust pipe 127. In this case, since the oxygen released from the maximum position A of the bubble discharge flows in the direction of the exhaust pipe 127, the oxygen released at the maximum position A of the bubble emission is higher than the temperature of the vapor space near the maximum temperature position R of the molten glass It is difficult to flow into the atmosphere.

In addition, the bubble discharge maximum position A and the position of the exhaust pipe 127 may be the same in the X direction. By setting the position of the maximum bubble emission amount A and the position of the exhaust pipe 127 at the same position in the X direction, the exhaust pipe 127 positioned above the oxygen emitted from the surface (liquid level) of the molten glass at the maximum bubble emission amount position A So that oxygen does not diffuse into the vapor phase space and flows toward the exhaust pipe 127 without flowing through the vapor phase space. Owing to this, the oxygen released from the surface (liquid level) of the molten glass at the maximum position A of the bubble emission is hardly used for the volatilization of the platinum group metal. The maximum position A of the bubble discharge and the position of the exhaust pipe 127 at the same position in the X direction means that the position of the center of the pipe of the exhaust pipe 127 in the X direction is the same as the pipe diameter of the exhaust pipe 127 Means that the maximum bubble emission amount position A is present in the region within the dimension range (region along the X direction). If the allowable range of the bubble discharge maximum position A is determined with respect to the bubble discharge maximum position A, this allowable range may be partially overlapped with the area within the dimension of the pipe diameter.

Even in the case where the temperature of the inner wall of the cleaning tube 120 in contact with the vapor phase space of the cleaning tube 120 is 1500 DEG C or higher, the present embodiment reduces the volatility of the platinum group metal and suppresses the aggregation of the platinum group metal volatiles, The effect becomes remarkable.

Also in any of the first and second embodiments, it is preferable that the vapor pressure of the platinum group metal in the vapor phase space is adjusted to suppress the volatilization of the platinum group metal. The vapor pressure of the platinum group metal in the vapor phase is preferably from 0.1 Pa to 15 Pa, more preferably from 3 Pa to 10 Pa.

In the first and second embodiments, the purifying tube 120 is used as an apparatus for processing a molten glass containing a purifying agent that releases oxygen by the reduction reaction. However, the purifying tube 120 ). The portion for treating a molten glass having a vapor phase space and containing a refining agent for releasing oxygen by a reduction reaction is not limited to a refining tube.

(Experimental Example 1)

In order to confirm the effect of the first embodiment, tin oxide is used as the fining agent, and the finishing tube 120 of the first embodiment shown in Fig. 3 is used to purify the fused glass for one hour, Adjustment of the above embodiment was performed. After the clinkering, the sheet was molded into a sheet glass having a thickness of 0.5 mm and a thickness of 2270 mm x 2000 mm to prepare 100 sheets of glass substrates.

In Examples 1 to 8, the oxygen concentration in the vapor space 120a was adjusted to 0.1 to 3% by adjusting the oxygen release amount from the molten glass, the purge gas (N 2 ) supply amount, and the exhaust pipe 127 suction amount, Lt; / RTI > The oxygen concentration in Example 1 was 0%, the oxygen concentration in Example 2 was 0.1%, the oxygen concentration in Example 3 was 0.3%, the oxygen concentration in Example 4 was 0.5%, the oxygen concentration in Example 5 was 0.7% The oxygen concentration in Example 6 was adjusted to be 1%, the oxygen concentration in Example 7 was 2%, and the oxygen concentration in Example 8 was 3%.

As a conventional example, the oxygen concentration in the vapor space 120a was not adjusted. At this time, the oxygen concentration was 21%. The platinum agglomerates of the glass substrates were visually inspected and evaluated by the number of platinum agglomerates per 100 sheets. Platinum agglomerates having an aspect ratio of 100 or more and a maximum length of 100 占 퐉 or more were used as a platinum foreign matter to be inspected.

As a result of the above examination, it was confirmed that the number of platinum agglomerates was 0.10 / m3, 1.2 / m3, 3.9 / m3, 7.4 / m3, 12 / / M < 3 >, 113 pieces / m < 3 >. This result is smaller than the amount of foreign substances in the conventional example of 4306 pcs / m3. Thus, it can be seen that the amount of foreign matter can be reduced in Examples 1 to 8 compared to the conventional example. The number of bubbles remaining in the glass substrate as defects in Examples 1 to 8 was 34 pieces / m 3, 28 pieces / m 3, 19 pieces / m 3, 13 pieces / m 3, 11 pieces / m3, 15 pieces / m3, 88 pieces / m3, and 255 pieces / m3. This result is smaller than the amount of foreign matter of the conventional example of 19201 pieces / m3. Further, the glass composition of the glass substrate is 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%, Fe 2 O 3 is 0.05%, total amount of 0.2% mol of alkali metal oxide, the strain point is the temperature of the molten glass when the ℃ 660, a viscosity of 10 2.5 poise, was 1570 ℃.

Fig. 8 is a diagram showing the results of Examples 1 to 8 of Experimental Example 1. Fig. In FIG. 8, the results of the other embodiments are also plotted.

(Experimental Example 2)

In order to confirm the effect of the second embodiment, tin oxide is used as the fining agent and the finishing tube 120 of the second embodiment shown in Fig. 6 is used to purify the fused glass for one hour, Adjustment of the above embodiment was performed. Specifically, the temperature distribution of the molten glass was adjusted to change the maximum bubble discharge amount position A. After the clinkering, the sheet was molded into a sheet glass having a thickness of 0.5 mm and a thickness of 2270 mm x 2000 mm to prepare 100 sheets of glass substrates. At this time, in Example 9, the temperature of the molten glass was adjusted such that the maximum bubble emission amount position A and the maximum temperature position of the temperature distribution were spaced apart in the flow direction of the molten glass. The position of the exhaust pipe 127 was set between the maximum position A of the bubble discharge amount in the flow direction of the molten glass and the maximum temperature position of the temperature distribution.

As a conventional example, adjustment of the maximum temperature position of the temperature distribution and the maximum position A of the bubble emission amount is not performed. In this case, the maximum position A of the bubble emission amount and the maximum temperature position of the temperature distribution substantially coincide with each other.

The platinum agglomerates of the glass substrates were visually inspected and evaluated by the number of platinum agglomerates per 100 sheets.

The platinum agglomerates were platinum foreign materials having an aspect ratio of 100 or more and a maximum length of 100 탆 or more as a foreign object to be inspected.

As a result of the inspection, the number of platinum aggregates due to platinum incorporated into the glass substrate was 1/3 or less as compared with the conventional example in which the maximum temperature position of the bubble discharge amount coincided with the maximum temperature position of the temperature distribution. Example 9 The number of bubbles remaining as defects on the glass substrate was 300 pieces / m 3 or less. Thus, in Example 9, it was confirmed that the number of platinum agglomerates was reduced compared with the conventional example. 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%, Fe 2 O 3 0.05%, a total amount of 0.2% mol of alkali metal oxide, the strain point is the temperature of the molten glass when the ℃ 660, a viscosity of 10 2.5 poise, was 1570 ℃.

(Experimental Example 3)

The glass composition of the glass substrate 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, Mol%, and SnO 2 was changed to 0.1 mol%, a glass substrate was prepared in the same manner as in Example 1. At this time, the strain point of the glass substrate was 745 ° C.

As a result, it was found that the number of platinum agglomerates can be reduced compared to the conventional example, as in Experimental Example 1.

(Experimental Example 4)

The glass composition of the glass substrate in Experimental Example 2 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, Mol%, and SnO 2 0.1 mol%, respectively. At this time, the strain point of the glass substrate was 745 ° C.

As a result, it was found that the number of platinum aggregates can be reduced compared to the conventional example, as in Experimental Example 2.

While the present invention has been particularly shown and described with respect to a preferred embodiment thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Of course. In the above description, the clarifying tube has been described as an example of the processing apparatus. However, the present invention is not limited thereto. The present invention can also be applied to a dissolving tank, a stirring tank, a molding apparatus, a transfer tube, and a supply tube.

100: dissolution apparatus
101: Melting bath
103: stirring tank
104, 105: transfer pipe
106: Glass feed pipe
120: Blue sign
121a and 121b:
122: Power supply
123: control device
124a and 124b: purge gas supply pipe
125a, 125b: purge gas supply device
127: Exhaust pipe
128: oxygen concentration meter
200: forming device
300: Cutting device
A: Maximum amount of oxygen released
P: Maximum temperature position
R: Maximum temperature position range

Claims (21)

Comprising the step of treating a molten glass containing a refining agent which releases oxygen by a reduction reaction using a treatment apparatus wherein at least a part of the inner wall is made of a material containing a platinum group metal,
In the step of processing the molten glass,
The molten glass is flowed in a direction along a surface in contact with the vapor phase space of the molten glass in the processing apparatus,
Controlling the oxygen concentration in the vapor phase space so as to suppress the volatilization of the platinum group metal by adjusting the amount of oxygen released from the molten glass in the vapor phase space formed by the inner wall of the processing apparatus and the surface of the molten glass,
The amount of the oxygen released varies according to the position of the molten glass in the flow direction,
The distribution of the oxygen concentration in the flow direction of the molten glass in the vapor phase space is adjusted so as to suppress the volatilization of the platinum group metal by adjusting the distribution of the oxygen emission amount at the position in the flow direction of the molten glass
Wherein the glass substrate is a glass substrate. A method of manufacturing a glass substrate for processing molten glass using a processing apparatus for processing molten glass,
When treating a molten glass containing a refining agent that releases oxygen by a reduction reaction,
Wherein a molten glass is supplied to the upper part of the surface of the molten glass so as to form a vapor phase space in a processing apparatus in which at least a part of the inner wall is made of a material containing a platinum group metal,
The molten glass is flowed in the direction along the surface of the molten glass in contact with the vapor phase space in the processing apparatus,
Controlling the oxygen concentration in the vapor phase space so that volatilization of the platinum group metal is suppressed by adjusting the amount of oxygen released from the molten glass,
The amount of the oxygen released varies according to the position of the molten glass in the flow direction,
The distribution of the oxygen concentration in the flow direction of the molten glass in the vapor phase space is adjusted so as to suppress the volatilization of the platinum group metal by adjusting the distribution of the oxygen emission amount at the position in the flow direction of the molten glass
Wherein the glass substrate is a glass substrate. Comprising the step of treating a molten glass containing a refining agent which releases oxygen by a reduction reaction using a treatment apparatus wherein at least a part of the inner wall is made of a material containing a platinum group metal,
In the step of processing the molten glass,
The molten glass is flowed in a direction along a surface in contact with the vapor phase space of the molten glass in the processing apparatus,
Controlling the oxygen concentration in the vapor phase space so as to suppress the volatilization of the platinum group metal by adjusting the amount of oxygen released from the molten glass in the vapor phase space formed by the inner wall of the processing apparatus and the surface of the molten glass,
Wherein the temperature of the inner wall in contact with the vapor phase space of the processing apparatus has a temperature distribution along the flow direction of the molten glass and the amount of bubbles discharged from the surface of the molten glass to the vapor phase is maximized in the processing of the molten glass The bubble discharge maximum position is adjusted such that the maximum position of the bubble discharge in the flow direction of the molten glass and the maximum temperature position of the temperature distribution in the flow direction of the molten glass are spaced apart from the flow direction of the molten glass
Wherein the glass substrate is a glass substrate. A method of manufacturing a glass substrate for processing molten glass using a processing apparatus for processing molten glass,
When treating a molten glass containing a refining agent that releases oxygen by a reduction reaction,
Wherein a molten glass is supplied to the upper part of the surface of the molten glass so as to form a vapor phase space in a processing apparatus in which at least a part of the inner wall is made of a material containing a platinum group metal,
The molten glass is flowed in the direction along the surface of the molten glass in contact with the vapor phase space in the processing apparatus,
Controlling the oxygen concentration in the vapor phase space so that volatilization of the platinum group metal is suppressed by adjusting the amount of oxygen released from the molten glass,
Wherein the temperature of the inner wall in contact with the vapor phase space of the processing apparatus has a temperature distribution along the flow direction of the molten glass and the amount of bubbles discharged from the surface of the molten glass to the vapor phase is maximized in the processing of the molten glass The bubble discharge maximum position is adjusted such that the maximum position of the bubble discharge in the flow direction of the molten glass and the maximum temperature position of the temperature distribution in the flow direction of the molten glass are spaced apart from the flow direction of the molten glass
Wherein the glass substrate is a glass substrate. The glass substrate according to any one of claims 1 to 4, wherein the glass substrate contains 0.01 mol% to 0.3 mol% of tin oxide,
And the amount of oxygen released from the molten glass is adjusted according to the content of the tin oxide. 5. The method of manufacturing a glass substrate according to any one of claims 1 to 4, wherein the oxygen concentration is controlled by further adjusting an amount of oxygen discharged from the vapor phase space to the outside of the processing apparatus. The method of manufacturing a glass substrate according to any one of claims 1 to 4, wherein a gas whose supply amount is adjusted is supplied to the vapor phase space so that the oxygen concentration is within a predetermined range. The method according to claim 1 or 2, wherein the temperature of the processing apparatus changes in accordance with the position in the flow direction of the molten glass,
The distribution of the amount of oxygen emission is predicted using a computer simulation,
Wherein the processing conditions are determined using the computer simulation so that a position at which the amount of oxygen emission in the flow direction of the molten glass reaches a maximum is spaced apart from a position at which the temperature of the processing apparatus is maximized. A method of manufacturing a glass substrate for processing molten glass using a processing apparatus for processing molten glass,
And a step of melting the raw material of the glass to produce a molten glass,
And a refining agent which releases oxygen by a reduction reaction,
In the step of processing the molten glass,
Wherein a molten glass is supplied to the upper part of the surface of the molten glass so as to form a vapor phase space in the processing apparatus wherein at least a part of the inner wall is made of a material containing a platinum group metal, Flows in a direction along the surface in contact with the vapor space,
Wherein the temperature of the inner wall in contact with the vapor phase space of the processing apparatus has a temperature distribution along the flow direction of the molten glass and the amount of bubbles emitted from the surface of the molten glass in contact with the vapor phase in the processing of the molten glass The maximum bubble discharge amount maximum position in the flow direction of the molten glass and the maximum temperature position of the temperature distribution in the flow direction of the molten glass are spaced apart from the flow direction of the molten glass Wherein the glass substrate is a glass substrate. 10. The apparatus according to any one of claims 1 to 9, wherein the processing apparatus includes at least a purifying tube for defoaming the molten glass, at least a part of the inner wall being made of a material containing a platinum group metal ,
Wherein the step of treating the molten glass is a fining step including a defoaming step of defoaming the molten glass in the purifying pipe. 10. The method according to any one of claims 3, 4, and 9, wherein said bubble emission maximum position is predicted using a computer simulation,
And the processing conditions are determined using the computer simulation such that the maximum bubble emission amount position is spaced apart from the maximum temperature position and the flow direction of the molten glass. 10. The method according to any one of claims 3, 4, and 9, wherein adjustment of the maximum bubble discharge amount position is performed by adjusting at least one of a temperature distribution of the molten glass and a flow rate of the molten glass, / RTI > 10. The manufacturing method of a glass substrate according to any one of claims 3, 4, and 9, wherein the maximum bubble emission amount position is located on the downstream side of the flow of the molten glass with respect to the maximum temperature position. 10. The apparatus according to any one of claims 3, 4, and 9, wherein the processing apparatus includes at least a purifying tube for defoaming the molten glass, at least a part of the inner wall being made of a material containing a platinum group metal ,
Wherein the purifying tube is provided with an exhaust pipe communicating with the atmosphere in the vapor phase space and the outside of the processing apparatus,
Wherein an arrangement position of the exhaust pipe in the flow direction of the molten glass is between the maximum bubble emission amount position and the maximum temperature position. 10. The apparatus according to any one of claims 3, 4, and 9, wherein the processing apparatus includes at least a purifying tube for defoaming the molten glass, at least a part of the inner wall being made of a material containing a platinum group metal ,
Wherein the purifying pipe is provided with an exhaust pipe that communicates with the atmosphere outside the vapor-phase space and the purifying pipe,
Wherein the bubble discharge maximum position and the position of the exhaust pipe in the flow direction of the molten glass are on the same side in the flow direction of the molten glass with reference to the highest temperature position of the temperature distribution, . 15. The apparatus according to claim 14, wherein a flange member is provided on an outer periphery of the processing apparatus, the flange member extending outwardly of the processing apparatus, and the position of the flange member in the flow direction of the molten glass is determined by the bubble- In the region other than the region between the disposition positions of the glass substrates. 16. The apparatus according to claim 15, wherein a flange member is provided on the outer periphery of the processing apparatus, the flange member extending outwardly of the processing apparatus, and the position of the flange member in the flow direction of the molten glass, In the region other than the region between the disposition positions of the glass substrates. A glass substrate manufacturing apparatus for processing molten glass using a processing apparatus for processing molten glass,
Wherein at least a part of the inner wall is made of a material containing a platinum group metal and is supplied with a molten glass containing a refining agent which releases oxygen by a reduction reaction therein and a vapor phase space is formed on the surface of the molten glass A processing device in which the molten glass flows in a direction along a surface of the molten glass in contact with the vapor phase space,
And a control device configured to adjust the amount of oxygen released from the molten glass and adjust the amount of oxygen discharged from the vapor phase space so that the oxygen concentration in the vapor phase becomes a predetermined range,
The amount of the oxygen released varies according to the position of the molten glass in the flow direction,
The control device adjusts the distribution of the oxygen concentration in the flow direction of the molten glass in the vapor phase space so as to suppress the volatilization of the platinum group metal by adjusting the distribution of the oxygen emission amount at the position in the flow direction of the molten glass To do
Wherein the glass substrate is a glass substrate. A glass substrate manufacturing apparatus for processing molten glass using a processing apparatus for processing molten glass,
Wherein at least a part of the inner wall is made of a material containing a platinum group metal and is supplied with a molten glass containing a refining agent which releases oxygen by a reduction reaction therein and a vapor phase space is formed on the surface of the molten glass A processing device in which the molten glass flows in a direction along a surface in contact with the vapor space of the molten glass;
And a control device configured to adjust the amount of oxygen released from the molten glass and adjust the amount of oxygen discharged from the vapor phase space so that the oxygen concentration in the vapor phase becomes a predetermined range,
The temperature of the inner wall of the processing apparatus in contact with the vapor phase space has a temperature distribution along the flow direction of the molten glass,
Wherein the controller controls the maximum amount of the bubble discharge amount in the flow direction of the molten glass in which the amount of bubbles discharged from the surface of the molten glass to the vapor phase is maximized in the processing of the molten glass, Adjusting the maximum bubble discharge amount maximum position such that the maximum temperature position of the distribution is spaced apart from the flow direction of the molten glass
Wherein the glass substrate is a glass substrate. A glass substrate manufacturing apparatus for processing molten glass using a processing apparatus for processing molten glass,
A melting tank for melting the glass raw material to produce a molten glass;
Wherein at least a part of the inner wall is made of a material containing a platinum group metal and a molten glass containing a refining agent for releasing oxygen by a reduction reaction is supplied to the molten glass and a surface And the temperature of the inner wall in contact with the vapor space has a temperature distribution along the flow direction of the molten glass,
A maximum position of the bubble discharge amount in the flow direction of the molten glass and a maximum position of the temperature distribution in the flow direction of the molten glass in which the amount of bubbles released from the surface of the molten glass into the vapor phase is maximized in the processing of the molten glass And the maximum bubble emission amount position is adjusted so that the temperature position is spaced apart from the flow direction of the molten glass. 21. The glass substrate manufacturing apparatus according to any one of claims 18 to 20, wherein the processing apparatus includes a cleaning tube for defoaming the molten glass.
KR1020157001898A 2013-12-26 2014-12-26 Method and apparatus for making glass sheet KR101730743B1 (en)

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