TW201536696A - Glass plate production method and glass plate production device - Google Patents

Abstract

The present invention comprises: a formation step for forming a glass plate from molten glass using a downdraw method; a cooling step for cooling the glass plate formed in the formation step while transporting the glass plate downward in the vertical direction; a detection step for detecting the position of striae occurring in the transport direction of the glass plate cooled in the cooling step and detecting the degree of variation due to the striae; and a determination step for determining the position of striae for which the degree of variation detected in the detection step is equal to or greater than a reference amount. In the cooling step, the amount of heat retained by the glass plate is controlled in a compartment surrounded by a furnace wall so that the degree of variation at the striae positions determined during the determination step is equal to or less than the reference value.

Description

Glass plate manufacturing method and glass plate manufacturing device

The present invention relates to a method for producing a glass sheet and a device for producing a glass sheet.

In the past, as one of the manufacturing methods of the glass plate, a down-draw method has been employed. The down-draw method refers to a flow of molten glass that has overflowed from a molded body and flows down along the side of the molded body. Thereafter, the molten glass is joined to the lower end portion of the molded body to form a glass plate. The formed glass plate is conveyed downward in the vertical direction and cooled. In the cooling step, the glass plate changes from a viscous state to a viscoelastic state and then to an elastic state.

However, in a manufacturing apparatus for a glass sheet using a down-draw method, generally, a space in which a glass sheet which is released from the molded body is not in contact with any object and is cooled, that is, a slow cooling zone is divided into a plurality of heat-dissipating plates by a heat insulating plate. Cold space. The heat insulating plate is disposed for the purpose of suppressing the heat transfer of the slow cooling space, and controlling the temperature of each of the slow cooling spaces to a desired temperature distribution by suppressing the air flow moving in each of the slow cooling spaces. Here, the desired temperature distribution means, for example, a temperature distribution in which the glass sheet is not deformed in each of the slow cooling spaces in the slow cooling zone. That is, the glass plate is conveyed downward by the heat insulating plate, and is adjusted to a desired temperature in each of the slow cooling spaces. Therefore, the insulating sheet is important in that the glass sheet is slowly cooled to form a glass sheet having less deformation.

However, as for the thickness of the glass plate which is slowly cooled in the slow cooling zone, generally, both end portions in the width direction are larger than the central portion in the width direction. Therefore, as disclosed in Patent Document 1, when the glass plate is sandwiched between the one of the single plates and the glass plate is sandwiched, it is necessary to at least make the thickness of the glass plate at the maximum in the width direction at both ends so as not to contact the heat insulating plate. Degree, set one The size of the gap between the insulation panels. However, the larger the gap is, the easier it is to generate the airflow moving in each of the slow cooling spaces, so that the more easily the heat exchange between the slow cooling spaces is performed via the gap, and it is difficult to control the temperature of each of the slow cooling spaces. The problem of the desired temperature distribution.

Thus, since the prior art, a technique of thermally managing the slow cooling zone into a plurality of slow cooling spaces by using a heat insulating plate has been employed. On the other hand, in recent years, the specifications (quality) required for the thickness variation, warpage, deformation, and the like of the glass plate of the glass substrate for a liquid crystal display device have become stricter.

As described above, in the case where the glass sheet is produced by the following drawing method, in order to reduce the deformation, each of the slow cooling spaces is previously designed to have a desired temperature distribution, and the heat distribution of the atmosphere is performed in such a manner as to achieve the designed temperature distribution. However, in a state in which the airflow moving in each of the slow cooling spaces is generated, if the ambient temperature of each of the slow cooling spaces cannot be controlled to a desired temperature distribution, a line mark may be generated in the conveying direction of the glass sheet. The thickness (height) of the line-stained glass sheet is a type of deformation caused by a specific width variation, and is continuously generated in a strip shape along the conveying direction of the glass sheet. In order to suppress the occurrence of line marks and to meet the more stringent requirements in recent years, it is necessary to improve the accuracy of the designed temperature distribution. Therefore, it is also necessary to improve the thermal management accuracy.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2008-88005

Therefore, an object of the present invention is to provide a method for producing a glass sheet and a device for manufacturing a glass sheet, which are capable of suppressing the heat of the glass sheet by the position of the line mark along the direction in which the glass sheet is conveyed, thereby suppressing the line mark of the glass sheet. .

The present invention has the following forms.

(Form 1)

A method for producing a glass sheet, comprising: a forming step of forming a glass sheet from molten glass using a down-draw method; and a cooling step of transporting the glass sheet formed in the forming step downward in a vertical direction while being conveyed Cooling; a detecting step of detecting a position of a line mark generated by a conveying direction of the cooled glass sheet in the cooling step and a change amount caused by the line mark; and a determining step of determining the change detected in the detecting step The amount of the line mark is equal to or greater than the reference amount, and the position of the line mark determined in the above-described determination step is controlled so that the amount of change is equal to or lower than the reference amount.

(Form 2)

A method for producing a glass sheet, comprising: a forming step of forming a glass sheet from molten glass using a down-draw method; and a cooling step of transporting the glass sheet formed in the forming step downward in a vertical direction while being conveyed Cooling; a detecting step of detecting a position of a line mark generated by a conveying direction of the cooled glass sheet in the cooling step and a change amount caused by the line mark; and a determining step of determining the change detected in the detecting step The amount of the line mark is equal to or greater than the reference amount; and in the cooling step, the position of the line mark determined in the determining step in the furnace chamber surrounded by the furnace wall is such that the amount of change is equal to or less than the reference amount The way to control the heat retained by the above glass plates.

(Form 3)

A method for manufacturing a glass sheet, comprising: a forming step of forming a glass sheet from molten glass using a down-draw method; and cooling the glass sheet formed in the forming step while being conveyed vertically downward, and cooling the sheet; the detecting step is based on the sheet of the glass sheet a thickness deviation or a viscosity deviation, detecting a position of a line mark generated by a conveying direction of the cooled glass sheet in the cooling step; and in the forming step or the cooling step, in a furnace chamber surrounded by a furnace wall, a heat insulating plate disposed at a position opposite to the glass plate and dividing the furnace chamber into a plurality of spaces with respect to the conveying direction of the glass sheet to change the amount of heat retained by the glass sheet, and detected in the detecting step The position of the line mark is controlled such that the above-mentioned line mark satisfies a specific condition, and the heat of the above-mentioned glass plate is controlled by the above-mentioned heat insulating plate.

(Form 4)

The method for producing a glass plate according to the aspect 2, wherein the furnace chamber includes a heat insulating plate disposed at a position facing the glass plate, and dividing the furnace chamber into plural numbers with respect to a conveying direction of the glass plate. a space for changing the heat retained by the glass plate; wherein the plurality of heat control devices are disposed along the width direction of the glass plate in the heat insulating plate; and the heat control is opposite to the position of the line mark detected in the detecting step The device increases the amount of heat imparted to the glass sheet.

(Form 5)

The method for producing a glass plate according to the third aspect or the fourth aspect, wherein the heat insulating plate is divided into a plurality of the width direction of the glass plate; and in the cooling step, shortening the glass plate to be cooled and the detecting step The distance between the detected insulation and the segmented insulation board.

(Form 6)

A method of producing a glass sheet according to any one of the aspects 3 to 5, wherein: In the cooling step, a heat insulating plate is newly provided at the position of the line mark detected in the detecting step, and the distance between the glass plate and the heat insulating plate is shortened.

(Form 7)

The method for producing a glass sheet according to any one of the aspects 1 to 6, wherein the line mark has a specific width in a width direction of the glass sheet and is continuously generated in a conveying direction of the glass sheet.

(Form 8)

A manufacturing apparatus for a glass sheet, comprising: a molding apparatus that forms a glass sheet from a molten glass using a down-draw method, and cools the formed glass sheet while being vertically conveyed downward; and a detecting device a position of a line mark generated by a direction in which the glass sheet is formed and cooled by the forming apparatus, and a change amount of the line mark, and determining that the amount of change is a line mark position equal to or larger than a reference amount; and the forming apparatus is connected to the furnace In the furnace chamber surrounded by the wall, the amount of heat retained by the glass sheet is controlled so that the amount of change is equal to or less than the reference amount at the position of the line mark determined by the detecting means.

(Form 9)

A method for producing a glass sheet, comprising: a molding step of flowing molten glass overflowing from a molded body along both side surfaces of the molded body, and then merging in the vicinity of a lower end portion of the molded body to form a glass sheet; And the glass plate formed in the forming step is conveyed while being vertically conveyed downward, and is cooled; and the detecting step detects the position of the line mark generated by the conveying direction of the glass plate cooled in the cooling step, and the line And a determining step of determining a line mark position in which the amount of change detected in the detecting step is equal to or greater than a reference amount; The forming step includes: a heat changing member disposed at a position opposite to a lower end portion of the molded body to change a heat retained by the glass sheet; and a position of the line mark determined in the determining step to cause the detecting The amount of change detected in the step is equal to or less than the reference amount, and the amount of heat applied to the glass sheet by the heat-changing member is controlled.

(Form 10)

In the method of producing a glass sheet according to the aspect 9, the distance between the heat-changing member and the glass sheet is shortened in the forming step, and the heat retention of the glass sheet at the position of the line mark determined in the determining step is increased; In the cooling step, the glass plate having the increased heat is stretched in the width direction of the glass sheet, and is cooled.

(Form 11)

A method of producing a glass sheet according to aspect 9, wherein the heat varying member has a width equal to a width of the line trace detected in the detecting step.

(Form 12)

The method for producing a glass sheet according to any one of the aspects of the invention, wherein the line mark has a specific width in a width direction of the glass sheet and is continuously generated in a conveying direction of the glass sheet.

(Form 13)

A manufacturing apparatus for a glass sheet, comprising: a molding apparatus that melts molten glass overflowing from a molded body along both side surfaces of the molded body, and then joins a glass plate in the vicinity of a lower end portion of the molded body; and a cooling device a glass plate formed by the above forming device in a vertical direction And the determining device detects the position of the line mark generated by the conveying direction of the glass plate cooled by the cooling device and the amount of change caused by the line mark, and determines the detected line mark. The change amount is a line mark position equal to or larger than a reference amount; and the molding apparatus includes a heat change member disposed at a position facing the vicinity of the lower end portion of the molded body, and changing heat retained by the glass sheet; The position of the line mark determined by the determining means controls the amount of heat applied to the glass sheet by the heat varying member so that the amount of change is equal to or less than the reference amount.

According to the method for producing a glass sheet and the apparatus for producing a glass sheet according to the above aspect, the position of the line mark is generated in the direction in which the glass sheet is conveyed, and by controlling the amount of heat retained by the glass sheet, the line mark of the glass sheet can be suppressed.

10‧‧‧Formed body

11‧‧‧ Lower end of the formed body

12‧‧‧ slot

14‧‧‧Glass supply tube

20‧‧‧Parts

30‧‧‧Cooling roller

40‧‧‧Insulation components

40a‧‧‧Insulation components

40b‧‧‧Insulation components

40c‧‧‧Insulation components

40d‧‧‧Insulation components

40e‧‧‧Insulation components

40f‧‧‧Insulation member

40g‧‧‧Insulation member

40h‧‧‧Insulation member

41‧‧‧Insulation board

42a‧‧‧ forming area

42b‧‧‧Slow space

42c‧‧‧Slow space

42d‧‧‧Slow space

42e‧‧‧slow space

42f‧‧‧Slow space

42g‧‧‧slow space

42h‧‧‧Slow space

50a‧‧‧Conveying roller

50b‧‧‧Conveying roller

50c‧‧‧Conveying roller

50d‧‧‧Conveying roller

50e‧‧‧ conveying roller

50f‧‧‧Conveying roller

50g‧‧‧ conveying roller

50h‧‧‧Conveying roller

60‧‧‧ Temperature Control Unit

60a‧‧‧temperature control unit

60b‧‧‧temperature control unit

60c‧‧‧temperature control unit

60d‧‧‧temperature control unit

60e‧‧‧temperature control unit

60f‧‧‧temperature control unit

60g‧‧‧temperature control unit

60h‧‧‧temperature control unit

70‧‧‧Detection device

80‧‧‧ magnetic tube

100‧‧‧ glass plate manufacturing equipment

200‧‧‧melting tank

300‧‧‧Clarification tank

400‧‧‧Forming device

410‧‧‧Formed body containment department

420‧‧‧ Slow cooling zone

D1‧‧‧ distance

D2‧‧‧ distance

G‧‧‧glass plate

G1‧‧‧ end (left end)

G2‧‧‧Central Area

GS‧‧‧ line marks

MG‧‧‧ molten glass

Fig. 1 is a schematic configuration diagram of a glass sheet manufacturing apparatus of the present embodiment.

Fig. 2 is a schematic cross-sectional view showing the forming apparatus.

Fig. 3 is a schematic plan view showing the side of the molding apparatus.

Fig. 4 is a view showing a shape of one of the glass plates formed by the forming device in plan view.

Fig. 5 is a schematic view showing a state in which a heat insulating member for holding a glass sheet is viewed in a plan view.

Fig. 6 is a view showing the position of a line mark of a glass plate.

Fig. 7 is a view showing the position of the heat insulating plate for holding the glass plate in a plan view.

Fig. 8 is a view showing the relationship between the distance from the glass plate to the heat insulating plate and the amount of deformation.

Fig. 9 is a schematic view showing a state in which the heat insulating member for holding the glass sheet of the second embodiment is viewed.

Fig. 10 is a schematic view showing a state in which the heat insulating member for holding the glass sheet of the third embodiment is seen.

Fig. 11 is a schematic view showing a state in which the heat insulating member for holding the glass sheet of the fourth embodiment is laid down.

Fig. 12 (a) is a schematic cross-sectional view showing the lower end of the molded article of the fifth embodiment, and (b) is a plan view from the lower end side of the molded body of (a).

Fig. 13 is a view showing the relationship between the distance from the glass plate to the heat insulating plate and the amount of deformation.

Fig. 14 is a plan view showing the magnetic tube of the sixth embodiment as seen from the lower end side of the molded body.

(Embodiment 1)

Hereinafter, a method for producing a glass sheet and a glass sheet manufacturing apparatus according to the present embodiment will be described. Fig. 1 is a schematic configuration diagram of a glass sheet manufacturing apparatus of the present embodiment.

As shown in FIG. 1, the glass plate manufacturing apparatus 100 is comprised by the melting tank 200, the clarification tank 300, and the shaping|molding apparatus 400. In the melting tank 200, the glass raw material is melted to form molten glass. The molten glass generated in the melting tank 200 is sent to the clarification tank 300. In the clarification tank 300, the removal of the bubbles contained in the molten glass is performed. The molten glass after the bubbles are removed in the clarification tank 300 is sent to the forming apparatus 400. The molding apparatus 400 continuously forms the glass sheet G from the molten glass by, for example, an overflow down-draw method. Thereafter, the formed glass sheet G is cooled and cut into a glass plate of a specific size. The glass plate G is used as, for example, a glass substrate for a flat display (for example, a glass substrate for a liquid crystal display, a glass substrate for a plasma display, or a glass substrate for an organic EL display), a glass substrate for tempered glass such as a cover glass or a magnetic disk, and a glass substrate. A glass substrate in the form of a roll and a glass substrate in which an electronic device such as a semiconductor wafer is laminated.

(glass composition)

In the melting tank 200, a glass raw material is melted by a heating means (not shown) to produce molten glass. The glass raw material is prepared in such a manner that the glass of the desired composition can be substantially obtained. As an example of the glass composition, the alkali-free glass suitable as a glass substrate for a flat panel display or a flat panel display contains SiO ₂ : 50% by mass to 70% by mass, Al ₂ O ₃ : 10% by mass to 25% by mass, and B ₂ O ₃ : 0% by mass to 15% by mass, MgO: 0% by mass to 10% by mass, CaO: 0% by mass to 20% by mass, SrO: 0% by mass to 20% by mass, and BaO: 0% by mass to 10% by mass. Here, the total content of MgO, CaO, SrO, and BaO is 5% by mass to 30% by mass. Alternatively, the glass substrate suitable for use as a glass substrate for an oxide semiconductor display and a glass substrate for an LTPS display contains SiO ₂ : 55 mass % to 70 mass %, Al ₂ O ₃ : 15 mass % to 25 mass %, and B ₂ O ₃ : 0% by mass to 10% by mass, MgO: 0% by mass to 10% by mass, CaO: 0% by mass to 20% by mass, SrO: 0% by mass to 20% by mass, and BaO: 0% by mass to 10% by mass. Here, the total content of MgO, CaO, SrO, and BaO is 5% by mass to 30% by mass. In this case, the glass substrate preferably 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 flat panel display or a flat panel display, in addition to alkali-free glass, a glass containing a trace amount of alkali metal containing a trace amount of alkali can also be used. If the glass of the glass substrate is an alkali-free glass containing tin oxide or a glass containing a trace amount of alkali containing tin oxide, it suppresses the platinum group metal which is generated by the volatilization of the platinum group metal used for the inner wall of the clarification tank 300. The effect of the agglomerate foreign matter mixed into the molten glass is more remarkable. Compared to alkali glass, alkali-free glass or glass containing a small amount of alkali has a higher viscosity. Since the melting temperature is increased in the melting step, most of the tin oxide is reduced in the melting step. Therefore, in order to obtain a clarifying effect, it is necessary to increase the temperature of the molten glass in the clarification step to promote the reduction of tin oxide and lower the viscosity of the molten glass. Further, since the temperature at which tin oxide promotes the reduction reaction is higher than that of arsenious acid or ruthenium which has been used as a clarifying agent, it is necessary to increase the temperature of the inner wall of the clarification tank 300 in order to increase the temperature of the molten glass to promote clarification. That is, in the case of producing an alkali-free glass substrate containing tin oxide or a glass substrate containing a tin oxide-containing glass containing a small amount of alkali, since it is necessary to increase the temperature of the molten glass in the clarification step, volatilization of the platinum group metal is likely to occur. In addition, the alkali-free glass substrate means a glass which does not substantially contain an alkali metal oxide (Li ₂ O, K ₂ O, and Na ₂ O). In addition, the glass containing a trace amount of alkali is a glass in which the content of the alkali metal oxide (the content of Li ₂ O, K ₂ O, and Na ₂ O) is more than 0 and 0.8 mol% or less. The glass containing a trace amount of alkali contains, for example, 0.1% by mass to 0.5% by mass of an alkali metal oxide, and preferably 0.2% by mass to 0.5% by mass of an alkali metal oxide. Here, the alkali metal oxide is selected from at least one of Li ₂ O, Na ₂ O, and K ₂ O. The total content of the alkali metal oxides may also be less than 0.1% by mass.

The glass substrate produced according to the present embodiment may further contain 0.01% by mass to 1% by mass (preferably 0.01% by mass to 0.5% by mass) of SnO ₂ and 0% by mass to 0.2% by mass in addition to the above components. It is 0.01% by mass to 0.08% by mass of Fe ₂ O ₃ . The glass substrate produced according to the present embodiment preferably contains no or substantially no As ₂ O ₃ , Sb ₂ O ₃ and PbO in view of environmental load.

Moreover, as a glass substrate manufactured by this embodiment, the glass substrate of the following glass composition is further illustrated. Therefore, the glass raw material is blended so that the glass substrate contains the following glass composition. For example, when expressed in mol%, it contains 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 , and 5 to 20 mol% of RO (RO system MgO, The total amount of CaO, SrO and BaO), 0 to 0.4 mol% of R' ₂ O (the total amount of R'-based Li ₂ O, K ₂ O and Na ₂ O), and 0.01 to 0.4 mol% of SnO ₂ . In this case, at least one of SiO ₂ , Al ₂ O ₃ , B ₂ O _{3 ,} and RO (all elements contained in the glass substrate of the R-based Mg, Ca, Sr, and Ba) may be contained. ((2 × SiO ₂ ) + Al ₂ O ₃ ) / ((2 × B ₂ O ₃ ) + RO) may be 0.4 or more. A glass having a high temperature viscosity of 4.0 or more in a molar ratio of (2 × SiO ₂ ) + Al ₂ O ₃ ) / ((2 × B ₂ O ₃ ) + RO) is exemplified.

Next, the detailed configuration of the molding apparatus 400 will be described. Fig. 2 is a schematic cross-sectional view showing a forming apparatus, and Fig. 3 is a schematic side view showing a forming apparatus.

As shown in FIGS. 2 and 3, the molding apparatus 400 is configured to include a molded body 10, a partition member 20, a cooling roller 30, heat insulating members 40a, 40b, ‧‧‧, 40h, conveying rollers 50a, 50b, ‧‧, 50h, temperature control unit (temperature control device, heat control device) 60a, 60b, ‧‧‧, 60h Further, the molding apparatus 400 has a molded body accommodating portion 410 which is a space above the partition member 20, a forming portion 42a which is a space directly under the partitioning member 20, and a slow cooling region 420 which is a space below the forming portion 42a. The slow cooling zone 420 has a plurality of slow Cold space 42b, 42c, ‧‧‧, 42h The forming zone 42a, the slow cooling space 42b, the slow cooling space 42c, ‧‧‧, 42h are stacked in this order from the upper direction to the lower side. The forming zone 42a and the slow cooling zone 420 are surrounded by a refractory material and/or a heat insulating material building (not shown). In the forming zone 42a and the slow cooling zone 420, the temperature control unit 60a or the like controls the glass sheet G to be suitable for forming. And the temperature of the cooling.

As shown in Fig. 2, the molded body 10 is a member having a substantially wedge-shaped cross-sectional shape. The molded body 10 is placed in the molded body accommodating portion 410 such that the tip end of the substantially wedge shape is located at the lower end. As shown in FIG. 3, a groove 12 is formed in the upper end surface of the molded body 10. The groove 12 is formed along the longitudinal direction of the molded body 10, that is, in the left-right direction of the surface of Fig. 3. At one end of the groove 12, a glass supply tube 14 is provided. The groove 12 is formed to gradually become shallower as it comes from the end portion of the glass supply tube 14 to the other end portion. A guide plate for preventing the molten glass from overflowing from the side wall is attached to both ends of the longitudinal direction of the molded body 10. The guide plate is wedge-shaped in plan view and is made of a plate material covering the entire end face of the molded body 10. In the vertical direction, the position of the front end of the guide plate coincides with the lower end of the formed body 10. The action of the guide plate can be used to cause the entire molten glass to flow along the side walls. The glass plate G is formed by fusing the molten glass at the lower end. However, since the molten glass is cut by the guide, the molten glass stays in the vicinity of the guide, that is, both ends in the longitudinal direction of the molded body 10. Therefore, as shown in FIG. 4, the end portion G1 in the width direction of the glass sheet G fused at the lower end of the molded body 10 has a bulbous shape having a thickness. The width direction of the glass sheet G refers to a direction orthogonal to the transport direction of the transport in the in-plane direction of the surface of the molten glass MG or the surface of the glass sheet G. Here, the end portion G1 means a portion having a specific thickness with respect to the thickness of the center of the glass sheet G in the width direction. Further, a region in the width direction sandwiched by the end portion G1 is referred to as a central region G2. Since the central region G2 and the end portion G1 are relatively thin and have a small amount of heat retention, it is easy to cause the heat to change due to the disorder of the airflow generated in the slow cooling zone 420 or the temperature unevenness of the temperature control unit 60, which is prone to warpage or Deformation. Therefore, it is necessary to strictly manage the cooling amount of the central area G2.

The partition member 20 is a plate-shaped heat insulating material disposed near the lower end of the molded body 10. Separate The member 20 is disposed such that the position in the height direction of the lower end thereof is located downward in the height direction from the lower end of the molded body 10. As shown in FIG. 2, the partition member 20 is disposed on both sides in the thickness direction of the glass sheet G. The partition body accommodating portion 410 and the forming portion 42a are partitioned by the partition member 20, and the movement of the heat from the molded body accommodating portion 410 to the forming portion 42a is suppressed. The molded body accommodating portion 410 and the forming portion 42a are partitioned by the partition member 20, which is a heat insulating material, in order to control the temperature of each of the molded body accommodating portion 410 and the forming portion 42a to prevent the temperature in the space between the two spaces from interfering with each other. Further, in order to suppress the volume flow rate of the airflow from the slow cooling zone 420 into the molded body accommodating portion 410, the partition member 20 is disposed by adjusting the interval between the glass plate G and the partition member 20 in advance.

In the forming zone 42a, the cooling roll 30 is disposed in the vicinity of the partition member 20. In addition, the cooling rolls 30 are disposed on both sides in the thickness direction of the glass sheet G, and serve to sandwich the end portion G1 of the glass sheet G while transporting the glass sheet G downward while sandwiching the glass sheet G in the thickness direction.

In the slow cooling zone 420, the heat insulating members 40a, 40b, ‧ ‧, 40h are divided into a plurality of slow cooling spaces 42b, 42c, ‧ ‧ with respect to the conveying direction of the glass sheet G (lower in the vertical direction) ‧, 42h, and suppress the thermal movement of each slow cooling space after the division. In addition, the heat insulating members 40a, 40b, ‧ ‧ , 40h are plate-shaped members which are disposed under the cooling rolls 30 and on both sides in the thickness direction of the glass sheets G, and have slit-shaped spaces for guiding the glass sheets G in the conveying direction. As described above, the forming zone 42a and the slow cooling zone 420 are surrounded by a refractory material and/or a heat insulating material building (not shown), but the slow cooling zone 420 has a slot-like space for the glass sheet G to be carried out, and is insulated. There are also some voids in the building and the like. Therefore, by the chimney effect, in the slow cooling zone 420, an ascending airflow from the vertical direction downward toward the forming zone 42a is generated. The air flow rises along the glass sheet G. Since the air flow causes the glass sheet G to be cooled, it is necessary to have the heat insulating members 40a, 40b, ‧ ‧, 40h for suppressing the air flow. For example, as shown in FIG. 2, the heat insulating member 40a forms a forming zone 42a and a slow cooling space 42b, and the heat insulating member 40b forms a slow cooling space 42b and a slow cooling space 42c. The heat insulating members 40a, 40b, ‧‧, 40h suppress heat transfer between the upper and lower spaces. For example, the heat insulating member 40a suppresses the forming region 42a and the slow cooling space. The heat transfer between the space 42b and the updraft, the heat insulating member 40b suppresses heat transfer and updraft between the slow cooling space 42b and the slow cooling space 42c.

In each of the heat insulating members 40a, 40b, ‧, ‧, 40h, a plurality of heat insulating plates 41 are combined and placed in close proximity to the glass plate G. Further, the heat insulating plate 41 can be moved in the thickness direction of the glass sheet G by an operation mechanism (not shown), thereby suppressing heat transfer and rising air flow. Fig. 5 is a schematic view showing a state in which the heat insulating member 40 for holding the glass sheet G is viewed in plan. In the present embodiment, the heat insulating member 40 is disposed at a position opposed to the glass sheet G as shown in the figure, and is formed by connecting a plurality of heat insulating plates 41 in the width direction of the glass sheet G. There is a gap between the glass plate G and the heat insulating member 40 (the heat insulating plate 41). The distance D1 of the gap can be arbitrarily set by moving the heat insulating plate 41 in the direction of the glass sheet G. If the airflow passes through the gap of the distance D1 and the glass sheet G is cooled, the glass sheet G cannot be adjusted to a desired temperature, which causes the glass sheet G to cause line marks. Therefore, by moving the heat insulating plate 41 at a position where the line mark is generated with the glass sheet G, the amount of cooling of the glass sheet G is adjusted, and the line marks generated by the glass sheet G can be suppressed.

In addition, the size and number of the heat insulating plates 41 can be arbitrarily set. For example, by reducing the size of the heat insulating plate 41, the plurality of heat insulating plates 41 may be connected to move the heat insulating plate 41 at a position opposite to the position where the line marks of the glass plate G are generated.

In the slow cooling zone 420, the conveying rollers 50a, 50b, ‧‧, and 50h are arranged in the vertical direction, and a plurality of them are disposed on both sides in the thickness direction of the glass sheet G at specific intervals. The conveying rollers 50a, 50b, ‧‧, and 50h are disposed in the slow cooling spaces 42b, 42c, ‧‧, and 42h, respectively, and the glass sheets G are conveyed downward.

The temperature control units 60a, 60b, ‧‧, 60h are composed of, for example, a jacket heater, a barrel heater, a ceramic heater, and a temperature sensor that generate heat by resistance heating, induction heating, and microwave heating, etc. In the width direction of the glass sheet G, it is disposed in the forming zone 42a and the slow cooling spaces 42b, 42c, ‧‧, 42h, and measures and controls the ambient temperature of the forming zone 42a and the slow cooling spaces 42b, 42c, ‧‧, and 42h. Also, the temperature control unit 60a, 60b, ‧ ‧, 60h control the forming zone 42a and the slow cooling space 42b, 42c in such a manner as to form a specific temperature distribution (hereinafter referred to as "temperature distribution") designed to avoid warping or deformation of the glass sheet G , ‧ ‧ , 42h ambient temperature Although the temperature (heat retention) of the glass sheet G varies depending on the atmosphere temperature of the forming zone 42a and the slow cooling space 42b, if the temperature of the atmosphere temperature is difficult to be uniform, and temperature unevenness with temperature difference is generated, the glass The temperature of the plate G also causes unevenness. The thickness of the central portion G2 of the glass plate G is as small as 0.05 to 1.0 mm, so that the heat retention thereof is easily changed, and warpage, deformation or line marks are liable to occur. The thickness of the central region G2 of the glass sheet G of the present embodiment is preferably 0.05 to 0.5 mm, more preferably 0.05 to 0.3 mm. If the thickness of the glass sheet G is thinner, the heat retention is more likely to change, and the warpage, deformation, or thickness deviation is more likely to occur, so the cooling amount of the central region G2 must be strictly managed. Hereinafter, when the temperature control units 60a, 60b, ‧, ‧, 60h are collectively referred to, they are described as the temperature control unit 60. In addition, the upstream side refers to the side opposite to the direction in which the glass sheet G is conveyed. In the present embodiment, the side of the molded body 10 is viewed from the slow cooling zone 420.

The detecting device 70 detects a portion of the line mark and detects deformation or surface unevenness of the glass sheet G at each position along the width direction of the glass sheet G. The detecting device 70 is composed of, for example, an optical sensor, a concave-convex detector, and a deformation detector, and detects a position of deformation and a deformation amount (deformation value, deformation amount, and deformation amount generated by the glass sheet G conveyed from the slow cooling zone 420 (slow cooling space 42h). Deformation), thickness deviation and viscosity deviation. For example, the detecting device 70 detects that the left end (left end portion G1) in the width direction of the glass sheet G is at a position of X1 mm to X2 mm, and has a deformation amount of Y. In particular, the detecting device 70 detects a line mark having a thickness (height) in the glass sheet G at a specific width (for example, a width of 10 mm). That is, the detecting device 70 detects the deformation or surface unevenness of the glass sheet G, and measures the amount of change in deformation or the amount of surface unevenness. Since the thickness of the glass sheet G is determined by the surface unevenness on both sides of the glass sheet G, the surface unevenness includes the variation in the thickness of the glass sheet G (variation in thickness). Further, since the amount of change in the deformation of the glass sheet G is determined by the viscosity of the glass sheet G, the amount of deformation includes the viscosity change (viscosity deviation) of the glass sheet G. Again, check The measuring device 70 determines whether or not the amount of change in the detected deformation or the amount of surface unevenness is equal to or greater than the reference amount, and determines the position at which the amount is equal to or greater than the reference amount as the position at which the line mark is generated. The line marks are caused by the shrinkage of the width direction of the glass sheet G due to the surface tension while the molten glass MG is separated from the lower end 11 of the molded body, and the surface unevenness of the glass sheet G is generated, and the unevenness is not suppressed in the slow cooling zone 420. Residual resulting in deformation. Since the cause is the shrinkage of the glass sheet G, the line marks are continuously generated in a strip shape along the conveying direction of the glass sheet G. Further, when the glass sheet G is molded, a heterogeneous glass component is mixed, and since the heat retained in one portion of the glass sheet G in which the heterogeneous glass component is mixed is different from the other portions, the portion in which the heat is retained becomes a line mark. In order to suppress the line mark, it is necessary to control only the temperature (heat retention) of the position in the width direction of the unevenness of the glass sheet G, but in the temperature control unit 60 which controls the atmosphere temperature of the slow cooling zone 420, only the strip shape is controlled. Part of the temperature is more difficult, and there is a situation where temperature distribution cannot be achieved. Therefore, by the position of the line mark detected by the detecting device 70 and the amount of change caused by the line mark (surface unevenness change, deformation change), the position of the heat insulating plate 41 is adjusted, and only one portion of the glass plate G whose temperature changes in a strip shape is controlled. The temperature is suppressed, and the line marks of the glass sheet G formed thereafter are suppressed.

The magnetic tube 80 is made of a metal material of a magnetic material and is connected to a power supply device (not shown). When an alternating current flows from the power supply device to the induction coil, the strength of the magnetic field changes to generate an eddy current in the magnetic tube. Joule heat is generated by the eddy current flowing in the magnetic tube 80, and the magnetic tube 80 is heated. The magnetic tube 80 is excellent in heat resistance and corrosion resistance, and is provided at a position on the upstream (upper) side of the partition member 20 at a position opposite to the lower end 11 of the molded body 10 which is at a high temperature, and the operating mechanism can be utilized (not As shown in the figure, it moves in the thickness direction and the width direction of the glass sheet G. By bringing the magnetic tube 80 closer to or away from the molten glass MG (glass plate G), the heat transferred from the magnetic tube 80 to the molten glass MG is adjusted to suppress deformation or unevenness generated in the glass sheet G. Further, by arranging a plurality of magnetic tubes 80 arranged in the width direction of the glass sheet G, the heat in the width direction of the glass sheet G is adjusted to suppress deformation or unevenness of the glass sheet G. Also, by shielding the heat radiation from the temperature control unit 60, the magnetic properties can be suppressed. The tube 80 imparts heat to the glass sheet G and controls the heat retention of the glass sheet G.

The magnetic tube 80 can be appropriately disposed on the upstream side (upper space side) of the deformation point at which deformation can be suppressed, for example, the position opposite to the lower end 11 of the formed body 10, the forming portion 42a, and the slow cooling portion 420 (slow cooling space 42b) , 42c, ‧‧, 42h). Here, the lower end 11 of the molded body 10 is within a range of, for example, 50 cm from the lower end 11. In order to suppress the line marks or deformation generated by the glass sheet G, the temperature control of the glass sheet G is performed from the lower end 11 of the molded body 10 to the vicinity of the deformation point. In particular, in order to suppress the line marks, it is preferable that the temperature of the lower end 11 to the central portion G2 of the formed body 10 becomes a slow cooling point, in particular, the temperature of the lower end 11 to the central portion G2 of the molded body 10 reaches the vicinity of the glass softening point. Within the range, the temperature control of the glass sheet G is performed. Further, in particular, in order to suppress deformation, it is preferable to perform temperature control of the glass sheet G in a range from the slow cooling point to the deformation point in the central region G2. Here, the vicinity of the glass softening point is preferably a temperature region from the glass softening point of -20 ° C to the glass softening point + 20 ° C. The tube diameter, the tube length, the tube shape, and the number of tubes of the magnetic tube 80 can be appropriately changed based on the position and amount of deformation of the glass sheet G. Further, since the magnetic tube 80 can heat or cool the molten glass MG (glass plate G), the temperature and viscosity of the molten glass MG can be changed, so that instead of the magnetic tube 80, a heater of a rod shape or a plate shape can be used. , a heat generating member, a cooling member, or a heat changing member. Further, instead of the magnetic tube 80, a heat insulating plate or a heat shielding plate for suppressing heat applied to the molten glass MG may be used.

Next, a method of suppressing the line marks (deformation) by reducing the cooling of the glass sheet G and making the heat retained in the width direction will be described.

First, the glass plate G and the slow cooling are formed by a general overflow down-draw method. The method of forming the glass sheet G and the slow cooling is described, for example, in the content described in JP-A-2008-88005, and the content can be considered. The glass sheet G is formed via a forming zone 42a and a slow cooling zone 420 (slow cooling space 42b, 42c, ‧ ‧, 42h) controlled by a temperature distribution designed to avoid deformation, but also due to the slow cooling zone 420 Airflow disorder, or ambient temperature The temperature is uneven, and a line mark is generated in one portion of the glass sheet G. Therefore, the position at which the line marks are generated and the amount of change caused by the line marks (surface unevenness change, deformation change (deformation amount, deformation value, deformation degree)), or the amount of unevenness is detected so as not to cause the glass plate G to be formed later The manner in which the line marks are generated causes the heat insulating plate 41 and the magnetic tube 80 to move, and the heat retained by the glass plate G is uniformized to suppress the line marks.

Next, the detecting device 70 detects the position and the amount of change (surface unevenness and deformation change) in the width direction of the line mark of the glass sheet G conveyed from the slow cooling zone 420 (slow cooling space 42h). Fig. 6 is a view showing the position in the width direction of the line mark GS of the glass sheet G. As shown in the figure, the detecting device 70 detects the line mark GS between the positions X1 to X2 of the left end portion of the glass plate G to be conveyed. Further, the detecting device 70 detects the amount of change (surface unevenness change, deformation change) caused by the detected line mark GS. Specifically, the detection device 70 also functions as a determination device, and determines whether or not the detected amount of change is equal to or greater than the reference amount, and determines the position at which the amount of change is equal to or greater than the reference amount as the position at which the line mark is generated. Here, the reference amount is changed depending on the required specifications of the glass sheet G, and is arbitrary. When the amount of change is equal to or greater than the reference amount, the detecting device 70 determines that the detected line mark GS located at the position X1 to X2 is a line mark whose amount of change should be suppressed to less than the reference amount. Since the line marks GS which are continuously generated in a strip shape along the conveying direction of the glass sheet G are generated due to air flow disturbance or temperature unevenness of the ambient temperature, if the air flow is not suppressed and the temperature unevenness is eliminated, the atmosphere temperature is uniformized. Then, it is continuously generated at a fixed position (here, positions X1 to X2) in the width direction of the glass sheet G. Further, since the temperature of the atmosphere is made uniform without eliminating the temperature unevenness, one portion of the glass sheet G is continuously cooled in a strip shape in the conveying direction, so that the amount of change caused by the line mark GS is substantially maintained. Therefore, by uniformizing the temperature of the atmosphere where the line mark GS is generated in the slow cooling zone 420, a specific temperature distribution is realized, and the line mark GS can be suppressed. Although the temperature control unit 60 can control the ambient temperature, it is difficult to control only the temperature at the position X1 to X2 at which the line mark GS is generated, and it is difficult to uniformize the heat retention in the width direction of the glass sheet G. Therefore, by controlling the distance between the glass sheet G and the heat insulating plate 41, the heat retained by the glass sheet G can be uniformized.

Next, the molding apparatus 400 controls the drive mechanism to set the position of the heat insulating plate 41 such that the ambient temperature in the vicinity of the positions X1 to X2 is uniform. Fig. 7 is a view showing a position where the heat insulating plate 41 sandwiching the glass sheet G in plan view is changed. The molding apparatus 400 moves the heat insulating plate 41 located at a position facing the position X1 to X2 of the line mark GS detected by the detecting device 70, and changes the distance between the glass plate G and the heat insulating plate 41 from D1 to D2. Fig. 8 is a view showing the relationship between the distance between the glass plate G and the heat insulating plate 41 and the amount of change (surface unevenness change, deformation change) caused by the line mark GS. Since the amount of change caused by the line mark GS does not satisfy the required quality at the distance D1 from the glass plate G to the heat insulating plate 41, the molding apparatus 400 changes the position of the heat insulating plate 41, as shown in the figure, from the distance D1 to the distance D2. . At a distance D2, the line mark GS of the glass sheet G satisfies the required quality. If the distance from the heat insulating plate 41 to the glass plate G provided at the position opposite to the position at which the line mark GS is generated is shortened, the air flow passing through the position is suppressed, the cooling amount of the glass plate G is reduced, and the ambient temperature is uniformized. . That is, when the heat insulating plate 41 is brought close to the glass plate G, the heat radiation from the heat insulating plate 41 is increased in a portion of the glass plate G opposed to the heat insulating plate 41, and only the glass plate facing the heat insulating plate 41 is placed. The temperature of G (holding heat) rises. The temperature distribution controlled by the temperature control unit 60 can be realized by heating only the position where the line mark is generated, that is, the strip position at which the temperature of the glass sheet G is lowered, and changing the gap of the glass sheet G in the transport direction. Moreover, the amount of change (surface unevenness change and deformation change) of the glass plate G formed after changing the distance from the glass plate G to the heat insulating plate 41 to D2 satisfies the required quality. Further, the relationship between the distance from the glass plate G to the heat insulating plate 41 and the amount of change (surface unevenness change, deformation change) can be obtained by gradually changing the distance and detecting the amount of change, and also depending on the ambient temperature and the glass plate G. The temperature is obtained by simulating the amount of change.

The line mark GS of the glass sheet G is generated before the temperature of the glass sheet G reaches the deformation point. Here, the term "deformation point" refers to a deformation point of a general glass, which corresponds to a temperature of 10 ^14.5 poise (for example, 661 ° C). The deformation point of the glass plate G may be 650 ° C or higher, preferably 660 ° C or higher, more preferably 690 ° C or higher, and particularly preferably 730 ° C or higher. Glass with a higher deformation point tends to have a higher viscosity of the molten glass. In the case where a heterogeneous glass component is mixed during the molding of the glass G, the glass having a higher viscosity has a more difficult diffusion of the heterogeneous glass component, so that the line mark GS is more likely to be generated. Therefore, the glass having a higher deformation point is more suitable for the present invention in which the effect of reducing the line mark GS is remarkable. Therefore, in order to suppress the line mark GS, it is necessary to control the temperature of the glass sheet G (holding heat) before the temperature of the glass sheet G reaches -50 ° C from the deformation point. In the forming zone 42a and the slow cooling zone 420, the temperature of the glass sheet G becomes a region from the deformation point of -50 ° C or more to the region from the heat insulating member 40a to the heat insulating member 40f. Therefore, by changing the position of the heat insulating plate 41 located at the position from the heat insulating member 40a to the heat insulating member 40f, the amount of heat applied to the glass plate G from the heat insulating plate 41 is increased, and the line mark GS of the glass plate G can be effectively suppressed. The temperature control of the glass sheet G by the heat insulating plate 41 is the same as that of the magnetic tube 80.

By changing the position of the line mark GS detected by the detecting device 70 and the amount of change caused by the line mark GS, the position adjustment of the heat insulating plate 41 is repeated, and the glass formed by adjusting the position of the heat insulating plate 41 can be suppressed. The line G of the board G marks GS. Further, when there are a plurality of line marks GS in the glass sheet G, the position of the heat insulating plate 41 at a position opposite to the position at which the plurality of line marks GS are generated is repeatedly adjusted by the molding apparatus 400, thereby suppressing the glass sheet G. Line mark GS.

As described above, according to the present invention, by adjusting the position of the heat insulating plate opposed to the line mark generated by the glass sheet, the atmosphere temperature is made uniform, and the line marks of the glass sheet formed after the position adjustment can be suppressed. Further, by suppressing the air flow and reducing the amount of cooling of the glass sheet, it is possible to avoid the temperature distribution designed to avoid the occurrence of line marks.

(Embodiment 2)

Next, in the case where the heat insulating member 40 is integrally molded, a method of suppressing the line mark GS of the glass sheet G by providing the heat insulating plate 41 along the heat insulating member 40 will be described. Incidentally, the same configurations as those of the above-described embodiment will be omitted.

Fig. 9 is a schematic view showing a state in which a heat insulating member for holding a glass sheet according to the embodiment is seen. As shown in the figure, the heat insulating plate 41 is provided along the heat insulating member 40. The heat insulating plate 41 can be inserted into the slot by the glass plate G formed by the lower end of the slow cooling space 42h, for example. It is provided inside the cold zone 420. Further, the method of providing the heat insulating plate 41 can be arbitrarily changed according to the configuration of the forming zone 42a and the slow cooling zone 420.

The forming device 400 discloses the position and the amount of deformation of the line mark GS detected by the detecting device 70 to, for example, the operator of the forming device 400. The position of the heat insulating plate 41 is set to be opposite to the position at which the line mark GS is generated, and the heat insulating plate 41 has a length corresponding to the length of the line mark GS in the width direction, and has a distance from the glass plate G to the heat insulating plate 41. The size of the thickness of the distance D2 that satisfies the required quality. As shown in FIG. 9, by providing the heat insulating plate 41 along the heat insulating member 40, the line mark GS of the glass plate G formed after the heat insulating plate 41 is provided can be suppressed.

As described above, according to the present invention, since the heat insulating plate corresponding to the position of the line of the glass sheet and the amount of change (surface unevenness and deformation change) caused by the line mark can be provided, the line mark of the glass sheet can be appropriately suppressed. . Moreover, even when the heat insulating member is integrally formed, since the distance from the glass plate to the heat insulating member (heat insulating plate) can be arbitrarily changed, the line mark of the glass plate after the distance change can be suppressed.

(Embodiment 3)

Next, a method of suppressing line marks generated between the end portion G1 of the glass sheet G and the central portion G2 will be described. Incidentally, the same configurations as those of the above-described embodiment will be omitted.

As shown in FIG. 4, the glass sheet G includes a central portion G2 having a substantially uniform thickness and an end portion G1 having a thickness thicker than the central portion G2. Since the both end portions G1 are thicker than the central portion G2 having a substantially uniform thickness, the heat retention is greater than that of the central portion G2, and since the end portions G1 and the central portion G2 have a heat retention difference, the both end portions G1 and the central portion G2 are present. Stress is generated between them, causing warpage or deformation of the glass sheet G. Therefore, the line mark GS (deformation) is reduced by making the heat retention between the both end portions G1 and the central portion G2 equal. As shown in FIG. 8, the amount of change (deformation amount) varies depending on the distance from the glass sheet G to the heat insulating member 40. Therefore, the distance from the end portion G1 to the heat insulating member 40 is substantially equal to the distance from the central portion G2 to the heat insulating member 40, and the distances are equal to or less than the distance satisfying the required quality.

Fig. 10 is a schematic view showing a state in which the heat insulating member for holding the glass sheet of the embodiment is seen. As shown in the figure, the heat insulating plate 41 has an inclined shape in order to make the distance between the end portion G1 and the central portion G2 to the heat insulating plate 41 substantially equal. The line mark GS between the both end portions G1 and the central portion G2 is caused by the difference in heat retention caused by the difference in thickness, so the amount of deformation is not the same in the width direction. Therefore, by arranging the insulating plate 41 having the inclined shape along the heat insulating member 40, the ambient temperature is made uniform, and the glass plate G is cooled by a temperature distribution designed to avoid the occurrence of the line mark GS. Thereby, the line mark GS of the glass sheet G formed after the heat insulation board 41 is provided can be suppressed.

Further, the shape and size of the heat insulating plate 41 can be arbitrarily changed based on the width and amount of change of the line mark GS of the glass plate G.

As described above, according to the present invention, it is possible to suppress the occurrence of line marks on the end portion and the central portion of the glass sheet. Moreover, even when the heat insulating member is integrally formed, since the distance between the both end portions and the central portion to the heat insulating member (heat insulating plate) can be arbitrarily changed, the line mark of the glass sheet after the distance change can be suppressed.

(Embodiment 4)

Next, a method of controlling the line marks of the glass sheet G by providing a plurality of temperature control units (temperature control means, heat control means) 60 by the heat insulating member 40 will be described. Incidentally, the same configurations as those of the above-described embodiment will be omitted.

Fig. 11 is a schematic view showing a state in which the heat insulating member for holding the glass sheet of the embodiment is seen. As shown in the figure, in the heat insulating member 40, a plurality of temperature control units 60 are provided along the width direction of the glass sheet G. The temperature control unit 60 is provided, for example, on the opposite side (side) of the surface (side) where the heat insulating member 40 faces the glass sheet G, and controls the temperature (heat generation) to control the amount of heat supplied from the heat insulating member 40 to the glass sheet G. The temperature control unit 60 corresponding to the position of the line mark GS detected by the detecting device 70 can increase the amount of heat applied to the glass sheet G by increasing the amount of heat generation, thereby suppressing the line mark GS generated by the glass sheet G.

As described above, according to the present invention, since line marks can be produced corresponding to the glass plate The position and the amount of change caused by the line marks (change in surface unevenness and deformation) increase the amount of heat, so that the line marks of the glass plate can be appropriately suppressed. Further, even when the heat insulating member is integrally molded, the heat applied to the glass sheet can be arbitrarily changed, and the line marks of the glass sheet can be suppressed.

(Embodiment 5)

Next, a method of suppressing the line marks of the glass sheet G by adjusting the installation positions of the plurality of magnetic tubes 80 will be described. Incidentally, the same configurations as those of the above-described embodiment will be omitted.

The molding apparatus 400 sets the position of the magnetic tube 80 provided in the vicinity of the lower end 11 of the molded body 10 so that the temperature of the atmosphere near the positions X1 to X2 can be made uniform by controlling the drive mechanism. Fig. 12(a) is a schematic cross-sectional view showing the lower end 11 of the molded body 10, and Fig. 12(b) is a plan view from the lower end 11 side of the molded body 10 of Fig. 12(a). As shown in FIG. 12, the magnetic tube 80 of the present embodiment is disposed on the upstream side of the transporting direction of the glass sheet G in the partitioning member 20 which is separated from the partitioning step and the cooling step (step of slowly cooling the glass sheet G) (formed body 10) On the side). The molding apparatus 400 moves the magnetic tube 80 to a position in the same width direction as the positions X1 to X2 of the line mark GS detected by the detecting device 70, and sets the distance between the molten glass MG and the magnetic tube 80 to D1. By heating the molten glass MG and the glass sheet G by the magnetic tube 80, the shrinkage generated when the glass sheet G is separated from the lower end 11 can be suppressed. When the line mark GS is generated at the position X1 to X2 detected by the detecting device 70, when the glass plate G (melted glass MG) leaves the lower end 11, the line mark GS is generated at the same position X1 to X2. Therefore, as shown in the figure, the molding apparatus 400 is provided with the magnetic tube 80 at the positions X1 to X2 in the width direction, and heats the glass sheet G (molten glass MG) to change the viscosity of the glass sheet G to suppress shrinkage. Moreover, FIG. 13 is a view showing the relationship between the distance between the molten glass MG and the magnetic tube 80 and the amount of change (surface unevenness change, deformation change). When the magnetic tube 80 is not disposed in the width direction of the deformation and the unevenness which cannot be removed in the slow cooling zone 420 (the [non-magnetic tube] in FIG. 13), the line mark GS detected by the detecting device 70 is caused. The amount of change (surface unevenness, deformation change) is not full Foot quality requirements. Therefore, the molding apparatus 400 controls the driving mechanism to move the magnetic tube 80 so as to be close to the molten glass MG, and sets the distance between the molten glass MG and the magnetic tube 80 so as to satisfy the required distance D1. That is, the distance is controlled so as to vary according to the amount of deformation change or the amount of surface unevenness obtained by the measurement so that the glass sheet G satisfies the required specifications. As shown in the figure, at the distance D1, the line mark GS of the glass sheet G which has been slowly cooled in the slow cooling zone 420 satisfies the required quality. When the distance from the magnetic tube 80 to the molten glass MG which is located at the position opposite to the position at which the line mark GS is generated is shortened, since the amount of heat from the magnetic tube 80 is increased by the molten glass MG, the viscosity of the molten glass MG is lowered. Therefore, the viscosity of the glass plate G (melted glass MG) leaving the lower end 11 is also lowered. The glass sheet G that has left the lower end 11 is conveyed while being held by the cooling roller 30 at its end portion G1, and is prevented from being shrunk in the width direction. However, since the glass sheet G having a low viscosity is easily deformed, the cooling roller 30 is used. Stretching the glass sheet G in the width direction suppresses shrinkage and suppresses the line marks GS generated by the glass sheet G. By changing the amount of deformation of the glass sheet G conveyed to the slow cooling zone 420 to a certain value or less, the amount of change (deformation amount) of the glass sheet G subjected to temperature management in the slow cooling zone 420 with a specific temperature distribution satisfies the required specifications. Therefore, the amount of change (surface unevenness change, deformation change) of the glass sheet G formed after the magnetic tube 80 is provided satisfies the required quality. Further, the relationship between the distance from the molten glass MG to the magnetic tube 80 and the amount of change can be obtained by gradually changing the distance and detecting the amount of change, and can be obtained by simulating the amount of change based on the temperature or viscosity of the glass sheet G or the like.

The molding apparatus 400 repeats the positional adjustment of the magnetic tube 80 based on the position of the line mark GS detected by the detecting device 70 and the amount of change (deformation amount) caused by the line mark GS, thereby suppressing the position adjustment of the magnetic tube 80. The line mark GS of the formed glass sheet G. Further, when there are a plurality of line marks GS in the glass sheet G, the molding apparatus 400 can suppress the glass sheet G by moving the plurality of magnetic tubes 80 to a position in the width direction corresponding to the position at which the plurality of line marks GS are generated. The line marks GS.

As described above, according to the present invention, the line amount of the formed glass sheet can be caused by suppressing the amount of deformation and the unevenness to a certain level or less before transporting the glass sheet to the slow cooling zone. The amount of change meets the required specifications, that is, the required conditions. Further, even in the case where a glass sheet which does not satisfy the required specification is caused to have a line mark, the continuous generation of the line mark can be suppressed. Further, it is possible to suppress the occurrence of irregularities on the glass plate which is a cause of occurrence of line marks on the glass sheet.

(Embodiment 6)

Next, a method of suppressing the line marks of the glass sheet G by adjusting the installation positions of the plurality of magnetic tubes 80 will be described. Incidentally, the same configurations as those of the above-described embodiment will be omitted.

Fig. 14 is a plan view of the magnetic tube 80 of the present embodiment as seen from the lower end side 11 of the molded body 10. The magnetic tube 80 is provided in the vicinity of the lower end side 11 of the molded body 10 at a position facing the molten glass MG (glass plate G). The detecting device 70 detects the position of the concavities and convexities formed by the glass sheet G and the amount of the concavities and convexities. When the detected amount of the concavities and convexities is equal to or greater than the reference amount, it is determined that a line mark is generated at the position of the detected concavities and convexities. The positions X3 to X5 and the positions X6 to X7 in the figure are determined by the detecting device 70 to be positions where line marks exist. The position X3 to X5 of the glass G formed by the slow cooling zone 420 has a line mark, and when the line trace of the position X3 to X4 is larger than the position X4 to X5, the forming apparatus 400 moves the magnetic tube 80 to the formed body 10 The position corresponding to the position X3 to X5 in the vicinity of the lower end side 11 is then set such that the distance between the magnetic tube 80 and the molten glass MG is the distance D2 from the position X3 to X4, and the position X4 to X5 is the distance D3. The width of the magnetic tube 80 functioning as a heat-changing member that changes the amount of heat imparted to the molten glass MG is adjusted so as to be equal to the width of the detected line mark. Further, since the amount of change and the unevenness of the position X3 to X4 are larger than the amount of change and the unevenness of the position X4 to X5, the position of the magnetic tube 80 is set closer to the molten glass than the position X4 to X5 at the position X3 to X4. MG, that is, set to distance D2 <distance D3. Further, when the line G formed by the slow cooling zone 420 and the position X6 to X7 at the different positions of the line mark positions X3 to X5 form a line mark, the forming apparatus 400 moves the magnetic tube 80 to the surface of the formed line mark. On the side, the position corresponding to the position X6 to X7 in the vicinity of the lower end side 11 of the molded body 10 is further provided so that the distance between the magnetic tube 80 and the molten glass MG becomes D4. Wide width of line marks (position X3 to X5) When the distance is long, a plurality of magnetic tubes 80 are arranged side by side in the width direction of the molten glass MG so as to have the same distance from the position X3 to X5. Thereby, the line marks of the glass sheet G formed after the plurality of magnetic tubes 80 are disposed can be reduced. Further, when the amount of change caused by the line marks generated at one place is different, the distance between the magnetic tube 80 and the molten glass MG is changed for each of the magnetic tubes 80, and the distances D2 and D3 are set to correspond to the amount of change. Line marks are reduced. The molding apparatus 400 sets the magnetic tube 80 by the position in the width direction corresponding to the position of the line mark detected by the detecting device 70 in the vicinity of the lower end side 11 of the molded body 10, and sets the magnetic tube 80 based on the amount of change detected by the detecting device 70. The distance from the molten glass MG can be reduced according to the position and amount of change of the line mark.

Further, it is preferable that the width of the magnetic tube 80 functioning as a heat changing member that changes the amount of heat applied to the molten glass MG is adjusted to be equal to the width of the detected line mark.

As described above, according to the present invention, since the magnetic tube can be provided in accordance with the position and the amount of change of the line mark generated in the glass sheet, the line mark of the glass sheet can be appropriately suppressed. Further, since the position where the magnetic tube is disposed and the distance between the magnetic tube and the molten glass can be arbitrarily set, even when a line mark is not formed in the glass sheet which does not satisfy the required specification, the line mark can be suppressed.

In the above, the glass sheet manufacturing method and the glass sheet manufacturing apparatus of the present invention have been described in detail. However, the present invention is not limited to the above-described embodiments, and various modifications and changes can be made without departing from the spirit and scope of the invention. .

41‧‧‧Insulation board

D1‧‧‧ distance

D2‧‧‧ distance

G‧‧‧glass plate

GS‧‧‧ line marks

Claims (13)

A method for producing a glass sheet, comprising: a forming step of forming a glass sheet from molten glass using a down-draw method; and a cooling step of transporting the glass sheet formed in the forming step downward in a vertical direction while being conveyed Cooling; a detecting step of detecting a position of a line mark generated by a conveying direction of the glass plate cooled in the cooling step and a change amount caused by the line mark; and a determining step of determining the above-mentioned detection step The amount of change is a position of a line mark equal to or larger than the reference amount; and the position of the line mark determined in the above-described determination step is such that the amount of heat remaining in the glass sheet is controlled so that the amount of change is equal to or less than the reference amount. A method for producing a glass sheet, comprising: a forming step of forming a glass sheet from molten glass using a down-draw method; and a cooling step of transporting the glass sheet formed in the forming step downward in a vertical direction while being conveyed Cooling; a detecting step of detecting a position of a line mark generated by a conveying direction of the glass plate cooled in the cooling step and a change amount caused by the line mark; and a determining step of determining the change detected in the detecting step The amount of the line mark is equal to or greater than the reference amount; and in the cooling step, the position of the line mark determined in the determining step in the furnace chamber surrounded by the furnace wall is such that the amount of change is less than the reference amount In this way, the heat retained by the glass plate is controlled. A method for producing a glass sheet, comprising: a forming step of forming a glass sheet from molten glass using a down-draw method; and a cooling step of directing a glass sheet formed in the forming step to a vertical side The lower side is conveyed and cooled, and the detecting step detects the position of the line mark generated by the conveying direction of the cooled glass sheet in the cooling step based on the thickness deviation or the viscosity deviation of the glass sheet; In the step or the cooling step, the furnace chamber is divided into a plurality of spaces in a furnace chamber surrounded by the furnace wall at a position facing the glass sheet and in a conveying direction with respect to the glass sheet. The heat insulating plate that changes the amount of heat retained by the glass plate controls the position of the line mark detected in the detecting step to control the heat of the glass plate by the heat insulating plate so that the line mark satisfies a specific condition. The method for producing a glass sheet according to claim 2 or 3, wherein the furnace chamber includes a heat insulating plate disposed at a position facing the glass plate, and dividing the furnace chamber into plural numbers with respect to a conveying direction of the glass plate a space for changing the heat retained by the glass plate; wherein the plurality of heat control devices are disposed along the width direction of the glass plate in the heat insulating plate; and the heat control is opposite to the position of the line mark detected in the detecting step The device increases the amount of heat imparted to the glass sheet. The method for producing a glass sheet according to claim 3, wherein the heat insulating plate is divided into a plurality of the width direction of the glass plate; and the glass plate to be cooled is shortened and the position of the line mark detected in the detecting step is The distance to the divided insulation panels. The method for producing a glass sheet according to any one of claims 3 to 5, wherein a heat insulating plate is newly provided at a position of the line mark detected in the detecting step, and a distance between the glass plate and the heat insulating plate is shortened. The method for producing a glass sheet according to any one of claims 1 to 6, wherein The line marks have a specific width in the width direction of the glass sheet, and are continuously generated in the conveying direction of the glass sheet. A manufacturing apparatus for a glass sheet, comprising: a molding apparatus for forming a glass sheet from a molten glass by using a down-draw method, and cooling the formed glass sheet while being vertically conveyed downward; and detecting means for detecting a position of a line mark generated by a direction in which the glass sheet is formed and cooled, and a change amount caused by the line mark, and determining that the amount of change is a line mark position equal to or larger than a reference amount; and the forming device is attached to the furnace wall In the enclosed furnace chamber, the amount of heat retained by the glass sheet is controlled so that the amount of change is equal to or less than the reference amount at the position of the line mark determined by the detecting means. A method for producing a glass sheet, comprising: a molding step of flowing molten glass overflowing from a molded body along both side surfaces of the molded body, and then merging in the vicinity of a lower end portion of the molded body to form a glass sheet; And the glass plate formed in the forming step is conveyed while being vertically conveyed downward, and is cooled; and the detecting step detects the position of the line mark generated by the conveying direction of the glass plate cooled in the cooling step, and the line And a determining step of determining a position at which the amount of change detected in the detecting step is a line mark of a reference amount or more; and the forming step includes: a heat changing member disposed at a lower end of the formed body The position in the vicinity of the portion changes the amount of heat retained by the glass sheet; and the position of the line mark determined in the determining step is controlled such that the amount of change detected in the detecting step is equal to or less than the reference amount. The varying member imparts heat to the glass sheet. The method of producing a glass sheet according to claim 9, wherein in the forming step, the distance between the heat-changing member and the glass sheet is shortened, and the heat retention of the glass sheet at the position of the line mark determined in the determining step is increased; In the cooling step, the glass plate having the increased heat is stretched in the width direction of the glass sheet, and is cooled. The method of producing a glass sheet according to claim 9 or 10, wherein the width of the heat-changing member is equal to the width of the line mark detected in the detecting step. The method for producing a glass sheet according to any one of claims 9 to 11, wherein the line mark has a specific width in a width direction of the glass sheet and is continuously generated in a conveying direction of the glass sheet. A manufacturing apparatus for a glass sheet, comprising: a molding apparatus that melts molten glass overflowing from a molded body along both side surfaces of the molded body, and then joins a glass plate in the vicinity of a lower end portion of the molded body; and a cooling device And the glass plate formed by the molding device is conveyed while being vertically conveyed downward, and is cooled; and the determining device detects the position of the line mark generated by the conveying direction of the glass plate cooled by the cooling device, and the line mark The amount of change caused by the detected line mark is determined to be a line mark position equal to or greater than a reference amount; and the molding apparatus includes a heat changing member disposed at a position opposite to the lower end portion of the molded body The amount of heat retained by the glass sheet is changed, and the amount of heat applied to the glass sheet by the heat-changing member is controlled so that the amount of change is equal to or less than the reference amount at the position of the line mark determined by the determining device.