WO2013047585A1 - フラットパネルディスプレイ用ガラス基板の製造方法 - Google Patents

フラットパネルディスプレイ用ガラス基板の製造方法 Download PDF

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WO2013047585A1
WO2013047585A1 PCT/JP2012/074706 JP2012074706W WO2013047585A1 WO 2013047585 A1 WO2013047585 A1 WO 2013047585A1 JP 2012074706 W JP2012074706 W JP 2012074706W WO 2013047585 A1 WO2013047585 A1 WO 2013047585A1
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Prior art keywords
glass
temperature
glass substrate
cooling
mol
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PCT/JP2012/074706
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English (en)
French (fr)
Japanese (ja)
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小山　昭浩
浩幸 苅谷
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ＡｖａｎＳｔｒａｔｅ株式会社
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Priority to KR1020127031321A priority Critical patent/KR101476520B1/ko
Priority to CN201280003080.5A priority patent/CN103269988B/zh
Priority to JP2013509353A priority patent/JP5555373B2/ja
Publication of WO2013047585A1 publication Critical patent/WO2013047585A1/ja

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    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B17/00—Forming molten glass by flowing-out, pushing-out, extruding or drawing downwardly or laterally from forming slits or by overflowing over lips
    • C03B17/06—Forming glass sheets
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B17/00—Forming molten glass by flowing-out, pushing-out, extruding or drawing downwardly or laterally from forming slits or by overflowing over lips
    • C03B17/06—Forming glass sheets
    • C03B17/064—Forming glass sheets by the overflow downdraw fusion process; Isopipes therefor
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B17/00—Forming molten glass by flowing-out, pushing-out, extruding or drawing downwardly or laterally from forming slits or by overflowing over lips
    • C03B17/06—Forming glass sheets
    • C03B17/067—Forming glass sheets combined with thermal conditioning of the sheets
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B25/00—Annealing glass products
    • C03B25/04—Annealing glass products in a continuous way
    • C03B25/06—Annealing glass products in a continuous way with horizontal displacement of the glass products
    • C03B25/08—Annealing glass products in a continuous way with horizontal displacement of the glass products of glass sheets
    • C03B25/087—Annealing glass products in a continuous way with horizontal displacement of the glass products of glass sheets being in a vertical position
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
    • C03C3/089—Glass compositions containing silica with 40% to 90% silica, by weight containing boron
    • C03C3/091—Glass compositions containing silica with 40% to 90% silica, by weight containing boron containing aluminium
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F9/00—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements
    • G09F9/30—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/133302—Rigid substrates, e.g. inorganic substrates
    • 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

Definitions

  • the present invention relates to a glass substrate for a flat panel display. More particularly, the present invention relates to a method for producing a glass substrate for a low-temperature polysilicon thin film transistor (hereinafter referred to as LTPS • TFT (Low-Temperature-Polycrystalline-Silicon-Thin-Film-Transistor)) flat panel display.
  • LTPS • TFT Low-Temperature-Polycrystalline-Silicon-Thin-Film-Transistor
  • the present invention also relates to a method for producing a transparent oxide semiconductor thin film transistor (hereinafter referred to as TOS ⁇ TFT (Transparent Oxide-Semiconductor Thin-Film-Transistor)) glass substrate for flat panel display.
  • TOS ⁇ TFT Transparent Oxide-Semiconductor Thin-Film-Transistor
  • the present invention relates to a method for manufacturing a glass substrate used in a flat display manufactured by forming LTPS or TOS on a substrate surface. More specifically, the present invention relates to a method for producing a glass substrate for flat panel display, wherein the flat panel display is a liquid crystal display, and a method for producing a glass substrate for flat panel display, wherein the flat panel display is an organic EL display. .
  • LTPS thin film transistors
  • TFTs thin film transistors
  • Heat treatment at a relatively high temperature of ° C is necessary.
  • higher definition has been demanded for displays of small devices. Therefore, it is desired to suppress the pixel pitch shift as much as possible, and the suppression of the thermal contraction of the glass substrate at the time of manufacturing the display, which is the cause of the pixel pitch shift, is a problem.
  • suppression of thermal shrinkage is a problem.
  • Patent Document 1 Japanese Patent Application Laid-Open No. 2011-20864, the entire description of which is specifically incorporated herein by reference).
  • an object of the present invention is to produce a glass substrate for LTPS / TFT having a thermal contraction rate capable of suppressing pixel pitch deviation without using a glass having a composition suitable for weight reduction without impairing productivity. It is to provide a method. Furthermore, it is also possible to provide a method by which a glass substrate having a thermal shrinkage rate suitable for TOS / TFT can be manufactured using glass having a composition suitable for weight reduction without impairing productivity. It is an object of the invention.
  • the present inventors have found that a glass substrate for LTPS / TFT having a heat shrinkage ratio equal to or lower than a predetermined value can be manufactured by devising a glass composition, and the present invention has been completed. Furthermore, the present invention has been completed by finding that the glass substrate has a heat shrinkage rate equal to or lower than a predetermined value that can be used for TOS / TFT.
  • the present invention is as follows. [1] (First embodiment of the present invention) A method for producing a glass substrate for a flat panel display, (1) a melting step in which a glass substrate to be manufactured is prepared by melting raw materials so that the total amount of SrO and BaO is less than 8% by mass and has a strain point of 675 ° C. or higher; (2) a molding step of molding a glass ribbon from the molten glass by an overflow down draw method; (3) A cooling method for cooling the molded glass ribbon under the following condition (A), and a method for producing a glass substrate for a flat panel display.
  • the raw material is prepared so that the glass substrate to be produced exhibits a molar ratio (SiO 2 + 2 ⁇ Al 2 O 3 ) / B 2 O 3 of 9.5 or more.
  • the glass substrate manufactured through the cooling step (3) is heated from room temperature at 10 ° C./min, held at 550 ° C. for 1 hour, then cooled to room temperature at 10 ° C./min, and again at 10 ° C./min.
  • thermal shrinkage (ppm) ⁇ Shrinkage amount of glass before and after heat treatment / Glass length before heat treatment ⁇ ⁇ 10 6 [4] (Second embodiment of the present invention)
  • the glass substrate to be produced has a molar ratio (SiO 2 + 2 ⁇ Al 2 O 3 ) / B 2 O 3 of 9.5 or higher, substantially does not contain BaO, and has a strain point of 680 ° C. or higher.
  • a method capable of producing glass substrates for LTPS / TFT flat panel displays and TOS / TFT flat panel displays having a heat shrinkage ratio below a predetermined value, for example, less than 75 ppm, without impairing productivity. can do.
  • FIG. 1 is a schematic diagram (cross-sectional view) of an overflow downdraw molding apparatus. It is a schematic diagram (side view) of the overflow downdraw molding apparatus. It is a figure which shows the temperature profile in the predetermined
  • the present invention relates to a method for producing a glass substrate for flat panel displays such as LTPS ⁇ TFT and TOS ⁇ TFT.
  • the glass substrate manufactured with the manufacturing method of this invention can be used as a glass substrate of a liquid crystal display and an organic EL display, Therefore, this invention is a manufacturing method of the glass substrate for liquid crystal displays, and the glass for organic EL displays.
  • a method for manufacturing a substrate is included.
  • the method for producing a glass substrate for a flat panel display of the present invention includes the following melting step (1), molding step (2) and cooling step (3).
  • the manufacturing method of the glass substrate for LTPS * TFT flat panel displays is demonstrated to an example, the manufacturing method of the glass substrate for TOS * TFT flat panel displays can be implemented similarly.
  • the manufacturing method of the glass substrate for liquid crystal displays and the glass substrate for organic EL displays can be implemented similarly.
  • melting step (1) raw materials are prepared so that the glass substrate to be manufactured satisfies predetermined conditions, heated and melted, refined, and a molten glass that can be used for molding is prepared.
  • the purpose is to produce a glass substrate having a thermal shrinkage of not more than a predetermined value, and such a glass substrate is subjected to the cooling of the molded glass ribbon in the following cooling step (3) ( The object is that it can be manufactured even if it is carried out in A).
  • raw materials are prepared and heated and melted so that the glass substrate to be manufactured satisfies predetermined conditions.
  • the raw material is prepared so that the glass substrate to be produced has a total amount of SrO and BaO of less than 8% by mass and a strain point of 675 ° C. or higher.
  • SrO and BaO are components that can lower the devitrification temperature of glass.
  • the devitrification resistance and the meltability are improved when it is contained.
  • a density and a thermal expansion coefficient will rise. If the coefficient of thermal expansion increases, a glass substrate for LTPS • TFT flat panel display having a heat shrinkage rate lower than a predetermined value, for example, less than 75 ppm, cannot be produced without impairing productivity. If the density increases, the glass substrate cannot be reduced in weight, which is not preferable for LTPS / TFT.
  • SrO + BaO which is the total amount of SrO and BaO, is less than 8% by mass.
  • SrO + BaO is preferably 0 to 7% by mass, more preferably 0 to 5% by mass, still more preferably 0 to 3% by mass, and still more preferably 0 to 1% by mass.
  • SrO and BaO are not substantially contained.
  • the glass substrate to be manufactured has a strain point of 675 ° C or higher.
  • the strain point of the glass substrate of the present invention is preferably 680 ° C. or higher, more preferably 686 ° C. or higher, further preferably 690 ° C. or higher, more preferably 695 ° C. or higher, and still more preferably 700 ° C. or higher.
  • the strain point of the glass substrate can be appropriately selected depending on the composition of the glass substrate, and the glass composition capable of setting the strain point to 675 ° C. or higher will be described later.
  • a glass substrate having a small thermal shrinkage can be obtained when the strain point of the produced glass substrate is 675 ° C. or higher.
  • the thermal contraction rate of the glass substrate is not determined only by the strain point, but also varies depending on other characteristics and manufacturing processes, particularly cooling conditions in the cooling process.
  • the glass substrate to be produced has a molar ratio (SiO 2 + 2 ⁇ Al 2 O 3 ) / B 2 O 3 of 9.5 or more, and is substantially free of BaO.
  • the raw materials are prepared so as to have a strain point of 680 ° C. or higher.
  • the glass substrate to be produced is made of glass containing SiO 2 , Al 2 O 3 , and B 2 O 3 in both the first aspect and the second aspect of the present invention.
  • the glass raw material in the first aspect of the present invention, it is preferable to prepare the glass raw material so that the molar ratio (SiO 2 + 2 ⁇ Al 2 O 3 ) / B 2 O 3 in the glass substrate is 9.5 or more.
  • the glass raw material is prepared so that the molar ratio (SiO 2 + 2 ⁇ Al 2 O 3 ) / B 2 O 3 in the glass substrate is 9.5 or more.
  • the composition of the prepared glass raw material and the composition of the glass substrate to be manufactured may vary somewhat because some components volatilize and / or scatter during the manufacturing process.
  • the glass raw material is prepared in consideration of the volatilization amount and scattering and the desired composition of the glass substrate.
  • the content and molar ratio of the glass component mean values in the glass or glass substrate.
  • a total amount of SiO 2 and 2 times the Al 2 O 3 with respect to B 2 O 3 molar ratio of (SiO 2 + 2 ⁇ Al 2 O 3) (SiO 2 + 2 ⁇ Al 2 O 3) / B 2 O 3 Is an index of high strain point and devitrification resistance.
  • (SiO 2 + 2 ⁇ Al 2 O 3 ) / B 2 O 3 is less than 9.5, the strain point cannot be made sufficiently high, and the thermal contraction rate below a predetermined value, for example, without impairing productivity, for example, It becomes difficult to manufacture a glass substrate for LTPS • TFT having less than 75 ppm.
  • (SiO 2 + 2 ⁇ Al 2 O 3 ) / B 2 O 3 is preferably 25.0 or less, and 19.0 or less It is more preferable that From the above, (SiO 2 + 2 ⁇ Al 2 O 3 ) / B 2 O 3 is preferably in the range of 9.5 to 25.0, more preferably in the range of 9.5 to 19.0, and even more preferably more than 9.5 to It is in the range of 17.0, more preferably in the range of 10.0 to 15.5, and still more preferably in the range of 11.0 to 15.0.
  • the manufactured glass substrate does not substantially contain BaO in the first aspect of the present invention.
  • BaO is substantially not contained. Therefore, in these cases, when a glass raw material is prepared, a compound containing Ba as a glass raw material is not used.
  • substantially free of BaO means that the glass substrate is not intentionally contained in BaO, and BaO as an impurity inevitably mixed into the glass in the glass raw material or the manufacturing process. Even inclusion is not excluded.
  • composition of the glass substrate produced by the production method of the present invention examples include glass compositions containing SiO 2 60 to 78 mol%, Al 2 O 3 3 to 20 mol%, and B 2 O 3 0.1 to 15 mol%.
  • a glass composition containing SiO 2 60 to 78 mol%, Al 2 O 3 3 to 20 mol%, and B 2 O 3 3 to 15 mol% can be exemplified.
  • This glass is MgO 0-15 mol%, CaO 0-20 mol%, SrO 0-10 mol%, ZnO 0-5 mol%, K 2 O 0-0.8 mol%, Fe 2 O 3 0-0.1 mol%, and other clarifications An agent or the like can be further contained. Further, it is preferable that Sb 2 O 3 is not substantially contained and As 2 O 3 is not substantially contained.
  • SiO 2 is a skeletal component of glass and is therefore an essential component. When the content decreases, the strain point tends to decrease and the thermal expansion coefficient tends to increase. If the SiO 2 content is too small, it is difficult to reduce the density of the glass substrate. On the other hand, if the SiO 2 content is too high, the melting temperature tends to be extremely high and melting tends to be difficult. When SiO 2 content is too large, since the devitrification resistance also tends to decrease, there is a tendency that moldability is deteriorated. From such a viewpoint, the content of SiO 2 is preferably in the range of 60 to 78 mol%. The content of SiO 2 is more preferably in the range of 62 to 75 mol%, further preferably 63 to 72 mol%, and more preferably 65 to 71 mol%.
  • Al 2 O 3 is an essential component that increases the strain point. When there is too little content, a strain point will fall. Furthermore, the Young's modulus also decreases and the etching rate tends to decrease.
  • the Al 2 O 3 content is too large, the devitrification temperature of the glass rises, there is a tendency that moldability is deteriorated. From such a viewpoint, the content of Al 2 O 3 is preferably in the range of 3 to 20 mol%.
  • the content of Al 2 O 3 is more preferably in the range of 5 to 18 mol%, further preferably 5 to 15 mol%, more preferably 7 to 14 mol%, and still more preferably 10 to 14 mol%.
  • B 2 O 3 is an essential component that lowers the melting temperature of glass and improves meltability.
  • the content of B 2 O 3 is too small, there is a tendency for the meltability, the devitrification resistance, and the thermal expansion coefficient to increase.
  • the B 2 O 3 content is too small, it is difficult to reduce the density.
  • the B 2 O 3 content is preferably in the range of 0.1 to 15 mol%, more preferably in the range of 3 to 15 mol%, still more preferably 3 to 9.5 mol%, and still more preferably.
  • the B 2 O 3 content is preferably in the range of 0.1 to 15 mol%, more preferably in the range of 3 to 15 mol%, and still more preferably. It is in the range of 5 to 13 mol%, more preferably 5 to 12 mol%, still more preferably 6 to 10 mol%.
  • MgO is a component that improves meltability. Moreover, since it is a component which is hard to increase a density in alkaline-earth metal, when the content is increased relatively, it will become easy to achieve a low density. Although it is not essential, the meltability can be improved by inclusion. However, if the content of MgO is too large, the devitrification temperature of the glass increases rapidly, and the formability deteriorates. In particular, when it is desired to lower the devitrification temperature, it is preferable not to contain MgO substantially.
  • the MgO content is preferably 0 to 15 mol%, more preferably 0 to 10 mol%, still more preferably 0 to 5 mol%, still more preferably 0 to less than 2 mol%, still more preferably 0 to 1.5 mol%, even more preferably 0 to 1 mol%, still more preferably 0 to 0.5 mol%, still more preferably 0 to less than 0.2 mol%, most preferably substantially contained. Is not to.
  • CaO is an effective component for improving the meltability of glass without rapidly increasing the devitrification temperature of the glass. Moreover, since it is a component which is hard to increase a density in alkaline-earth metal, when the content is increased relatively, it will become easy to achieve a low density. When there is too little content, there exists a tendency for the meltability fall by melting temperature rise, and the devitrification fall by devitrification temperature rise. When there is too much CaO content, there exists a tendency for the increase of a thermal expansion coefficient and the raise of a density to arise.
  • the CaO content is preferably 0 to 20 mol%, more preferably 3.6 to 16 mol%, further preferably 4 to 16 mol%, more preferably 6 to 16 mol%, still more preferably more than 7 to 16 mol%, still more preferably. It is in the range of 8 to 15 mol%, more preferably 9 to 13 mol%.
  • SrO is a component that can lower the devitrification temperature. SrO is not essential, but if it is contained, devitrification resistance is improved, and further meltability is improved. When there is too much SrO content, a density will rise.
  • the SrO content is preferably 0 to 10 mol%, more preferably 0 to 5 mol%, still more preferably 0 to 3 mol%, still more preferably 0 to 2 mol%, still more preferably 0 to 1 mol%, still more preferably 0. It is in the range of less than ⁇ 0.5 mol%, and still more preferably in the range of less than 0 to 0.1 mol%. When it is desired to reduce the density of the glass, it is preferable that SrO is not substantially contained.
  • BaO is a component that can lower the devitrification temperature. BaO is not essential, but when it is contained, devitrification resistance is improved and meltability is also improved. Moreover, when there is too much BaO content, a raise of a density and an increase of a thermal expansion coefficient will arise.
  • the BaO content is preferably in the range of 0 to 10 mol%, more preferably 0 to less than 5 mol%, further preferably 0 to 3 molmol, more preferably 0 to 2 mol%, still more preferably 0 to 1 mol%. It is. In addition, it is preferable not to contain BaO substantially from a problem of environmental load.
  • Li 2 O and Na 2 O are components that improve the meltability, but are components that may be eluted from the glass substrate to deteriorate the TFT characteristics or increase the thermal expansion coefficient of the glass.
  • the content of Li 2 O and Na 2 O is preferably 0 to 0.5 mol%, more preferably 0 to 0.1 mol%, still more preferably 0 to 0.01 mol%, and still more preferably none.
  • K 2 O is a component that increases the basicity of the glass and promotes clarity. Moreover, it is a component which reduces specific resistance fall and melting temperature, and improves a meltability. Although it is not essential, when it is contained, the clarity is improved and the meltability is also improved. If the K 2 O content is too large, it may be eluted from the glass substrate and deteriorate the TFT characteristics. Also, the thermal expansion coefficient tends to increase.
  • the K 2 O content is preferably in the range of 0 to 0.8 mol%, more preferably 0.01 to 0.5 mol%, and still more preferably 0.1 to 0.3 mol%.
  • the glass substrate obtained by the manufacturing method of this invention can contain a clarifier.
  • a clarifier As the fining agent, SnO 2 is suitable. If the SnO 2 content is too small, the foam quality deteriorates. If the SnO 2 content is too large, devitrification is likely to occur.
  • the SnO 2 content is preferably in the range of 0.01 to 0.2 mol%, more preferably 0.03 to 0.15 mol%, and still more preferably 0.05 to 0.12 mol%.
  • Fe 2 O 3 is a component that lowers the specific resistance of glass in addition to having a function as a fining agent. In a glass having high viscosity in a high temperature range and difficult to understand, it is preferably contained in order to reduce the specific resistance of the glass. However, if the Fe 2 O 3 content is too high, the glass is colored and the transmittance is lowered. Therefore, the Fe 2 O 3 content is in the range of 0 to 0.1 mol%, preferably 0 to 0.05 mol%, more preferably 0.001 to 0.05 mol%, still more preferably 0.005 to 0.05 mol%, and still more preferably 0.005 to It is in the range of 0.02 mol%.
  • the glass substrate obtained by the production method of the present invention preferably contains substantially no As 2 O 3 from the viewpoint of environmental load.
  • the glass substrate of the present invention preferably contains 0 to 0.5 mol%, more preferably 0 to 0.1 mol%, and most preferably substantially no Sb 2 O 3 because of environmental load problems.
  • substantially does not contain means that a material that is a raw material of these components is not used in the glass raw material, and a component contained as an impurity in the glass raw material of another component, It does not exclude the mixing of components that elute from the production equipment into the glass.
  • (SiO 2 -Al 2 O 3 /2) is preferably less 66 mol%, more preferably 50 ⁇ 66 mol%, more preferably 56 ⁇ 64 mol%, more preferably from 57 to It is 63 mol%, more preferably 58 to 62 mol%.
  • SiO 2 + Al 2 O 3 is the total amount of SiO 2 and Al 2 O 3 is too small, there is a tendency that the strain point is lowered, while when too large, there is a tendency that the devitrification resistance is deteriorated. Therefore, SiO 2 + Al 2 O 3 is preferably 75 mol% or more, more preferably 76 to 88 mol%, still more preferably 77 to 85 mol%, and still more preferably 78 to 82 mol%.
  • B 2 O 3 + P 2 O 5 is preferably 0.1 to 15 mol%, more preferably 3 to 15 mol%, further preferably 3 to 9.5 mol%, more preferably 4 to 9 mol%, and still more preferably Is from 5 to 9 mol%, more preferably from 6 to 8 mol%.
  • B 2 O 3 + P 2 O 5 is preferably in the range of 0.1 to 15 mol%, more preferably 3 to 15 mol%, still more preferably 5 to The range is 13 mol%, more preferably 5 to 12 mol%, and still more preferably 6 to 10 mol%.
  • B 2 O 3 molar ratio CaO / B 2 O 3 of CaO with respect to the while preventing a decrease in strain point from the viewpoint of improving the meltability, preferably 0.5 or more, more preferably 0.9 or more, more preferably greater than 1.2 More preferably, it is in the range of more than 1.2 to 5, even more preferably in the range of more than 1.2 to 3, even more preferably in the range of 1.3 to 2.5, and most preferably in the range of 1.3 to 2. Further, from the viewpoint of sufficiently improving the meltability, it is preferably 0.5 to 5, more preferably 0.9 to 3, more preferably more than 1 to 2.5, more preferably more than 1.2 to 2, even more preferably more than 1.2 to The range is 1.5.
  • CaO / RO is an index of melting and devitrification resistance.
  • CaO / RO is preferably 0.5 to 1, more preferably 0.7 to 1, further preferably more than 0.85 to 1, more preferably 0.88 to 1, even more preferably 0.90 to 1, even more preferably 0.92 to 1, Most preferably, it is 0.95 to 1. By setting it as these ranges, devitrification resistance and meltability can be made compatible. Further, the density can be reduced.
  • RO + ZnO + B 2 O 3 which is the total amount of RO, ZnO, and B 2 O 3 , is too small, meltability tends to decrease. On the other hand, if the amount is too large, the strain point tends to decrease. Therefore, RO + ZnO + B 2 O 3 is preferably 7 to 30%, more preferably 7 to less than 25 mol%, more preferably 10 to 23 mol%, still more preferably 12 to 22 mol%, still more preferably 14 to 21 mol. %, Even more preferably in the range of 16-21 mol%. Further, from the viewpoint of sufficiently improving the meltability, it is preferably 7 to 30%, more preferably 12 to 27%, more preferably 14 to 25 mol%, and further preferably 17 to 23 mol%.
  • the total amount of SiO 2 and Al 2 O 3 (SiO 2 + Al 2 O 3) molar ratio of the RO with respect to RO / (SiO 2 + Al 2 O 3) is a strain point and the melting of the indicator. From the viewpoint of achieving both a high strain point and meltability, and a glass having both a high strain point and a reduced specific resistance, it is preferably in the range of 0.07 to 0.2, more preferably 0.08 to 0.18, and even more preferably 0.13 to 0.18. More preferably, it is in the range of 0.13 to 0.16.
  • R 2 O which is the total amount of Li 2 O, Na 2 O, and K 2 O, is a component that enhances the basicity of the glass, facilitates the oxidization of the fining agent, and exhibits fining properties. Moreover, it is a component which reduces specific resistance and melting temperature, and improves meltability.
  • R 2 O is not essential, but when it is contained, the foam quality and meltability are improved. However, when the R 2 O content is too large, the thermal expansion coefficient tends to increase.
  • R 2 O is preferably 0 to 0.8 mol%, more preferably 0.01 to 0.5 mol%, still more preferably 0.1 to 0.3 mol%.
  • K 2 O has a higher molecular weight than Li 2 O and Na 2 O, and thus is difficult to elute from the glass substrate. Therefore, when R 2 O is contained, it is preferable to contain K 2 O. That is, it is preferable that K 2 O mol% content> Li 2 O mol% content and / or K 2 O mol% content> Na 2 O mol% content. When the ratio of Li 2 O and Na 2 O is large, there is a strong risk of elution from the glass substrate and deterioration of TFT characteristics.
  • the molar ratio K 2 O / R 2 O is preferably in the range of 0.3 to 1, more preferably 0.5 to 1, still more preferably 0.8 to 1, and still more preferably 0.9 to 1.
  • RO which is the total amount of MgO, CaO, SrO and BaO, is a component that improves meltability. If the RO content is too small, the meltability deteriorates. When there is too much RO content, there exists a tendency for the fall of a strain point, the raise of a density, and the fall of a Young's modulus to arise. Moreover, when there is too much RO content, there exists a tendency for a thermal expansion coefficient to increase.
  • RO is preferably in the range of 3 to 25 mol%, preferably 4 to 16 mol%, more preferably 4 to 15 mol%, still more preferably in the range of less than 5 to 14 mol%, more preferably 6 It is in the range of ⁇ 14 mol%, more preferably in the range of 8 to 13 mol%, and still more preferably in the range of 9 to 12 mol%.
  • the glass substrate of the present invention has a devitrification temperature of preferably 1270 ° C. or lower, more preferably 1260 ° C. or lower, still more preferably 1250 ° C. or lower, and still more preferably 1200 ° C. or lower. If the devitrification temperature is 1270 ° C. or lower, the glass plate can be easily formed by the downdraw method. If the devitrification temperature is too high, devitrification is likely to occur, and it cannot be applied to the downdraw method.
  • the glass substrate of the present invention has an average coefficient of thermal expansion (100-300 ° C.) of preferably less than 55 ⁇ 10 ⁇ 7 ° C. ⁇ 1 , more preferably less than 28 to 40 ⁇ 10 ⁇ 7 ° C. ⁇ 1 , and even more preferably 30 to The range is less than 39 ⁇ 10 ⁇ 7 ° C. ⁇ 1 , more preferably less than 32 to 38 ⁇ 10 ⁇ 7 ° C. ⁇ 1 , and still more preferably less than 34 to 38 ⁇ 10 ⁇ 7 ° C. ⁇ 1 . Further, from the viewpoint of further reducing the thermal shrinkage rate, it is preferably less than 37 ⁇ 10 ⁇ 7 ° C.
  • thermal expansion coefficient is large, the thermal contraction rate tends to increase.
  • the thermal expansion coefficient is small, it is difficult to match the peripheral material such as metal and organic adhesive formed on the glass substrate with the thermal expansion coefficient, and the peripheral member may be peeled off.
  • the glass substrate of the present invention has a heat shrinkage ratio of preferably 75 ppm or less, more preferably 60 ppm or less, further preferably 55 ppm or less, more preferably 50 ppm or less, still more preferably 48 ppm or less, still more preferably less than 45 ppm, even more Preferably it is 43 ppm or less. If the thermal contraction rate (amount) becomes too large, a large pitch shift of pixels is caused, and a high-definition display cannot be realized. In order to control the heat shrinkage rate (amount) within a predetermined range, the strain point of the glass substrate is preferably set to 675 ° C. or higher.
  • the thermal shrinkage rate can be reduced (offline annealing) by providing a thermal shrinkage reduction treatment step after the cutting step described later.
  • the productivity is lowered and the cost is increased.
  • the heat shrinkage rate is preferably 5 to 75 ppm, more preferably 5 to 60 ppm, further preferably 8 to 55 ppm, more preferably 8 to 50 ppm, still more preferably 10 to 48 ppm, and even more. Preferably it is 10 to less than 45 ppm, and still more preferably 15 to 43 ppm.
  • the heat shrinkage rate is expressed by the following formula after heat treatment with a temperature rising / falling rate of 10 ° C./min and holding at 550 ° C. for 1 hour twice. More specifically, the temperature is raised from room temperature at 10 ° C./min, held at 550 ° C. for 1 hour, then lowered to room temperature at 10 ° C./min, raised again at 10 ° C./min, and then increased at 1 at 550 ° C. Hold for a while and cool to room temperature at 10 ° C / min.
  • Thermal shrinkage (ppm) ⁇ Shrinkage amount of glass before and after heat treatment / Glass length before heat treatment ⁇ ⁇ 10 6
  • the glass substrate of the present invention has a density of preferably 2.6 g / cm 3 or less, more preferably 2.5 g / cm 3 or less, further preferably 2.45 g / cm 3 or less, and further preferably 2.42 g / cm 3 or less. If the density becomes too high, it is difficult to reduce the weight of the glass substrate, and it is not possible to reduce the weight of the display.
  • the glass substrate of the present invention has a Tg of preferably 720 ° C. or higher, more preferably 730 ° C. or higher, further preferably 740 ° C. or higher, more preferably 750 ° C. or higher.
  • Tg preferably 720 ° C. or higher, more preferably 730 ° C. or higher, further preferably 740 ° C. or higher, more preferably 750 ° C. or higher.
  • it is appropriate to increase the Tg for example, to contain more components such as SiO 2 and Al 2 O 3 in the composition range of the glass substrate of the present invention.
  • the glass melt of the present invention has a temperature (melting temperature) exhibiting a viscosity (100 dP ⁇ s), preferably 1750 ° C. or less, more preferably 1600-1750 ° C., further preferably 1620-1730 ° C., more preferably 1650 It is in the range of ⁇ 1720 ° C. Glass having a low melting temperature tends to have a low strain point. In order to increase the strain point, it is necessary to increase the melting temperature to some extent. However, if the melting temperature is high, the load on the melting tank increases. Moreover, since energy is used in large quantities, cost also becomes high. In order to bring the melting of the glass within the above range, it is appropriate to contain components such as B 2 O 3 and RO that lower the viscosity within the range of the composition of the glass substrate of the present invention.
  • the molten glass of the present invention has a specific resistance (at 1550 ° C.) of preferably 50 to 300 ⁇ ⁇ cm, more preferably 50 to 250 ⁇ ⁇ cm, still more preferably 50 to 200 ⁇ ⁇ cm, more preferably 100 to 200 ⁇ ⁇ cm. It is a range. If the specific resistance becomes too small, the current value necessary for melting becomes excessive, and there is a risk that restrictions on the equipment may occur. If the specific resistance of the molten glass becomes too large, the current flows not to the glass but to the heat-resistant brick that forms the melting tank, and the melting tank may be melted.
  • the specific resistance of the molten glass can be adjusted to the above range mainly by controlling the RO, K 2 O, and Fe 2 O 3 contents.
  • the glass of the present invention has a liquidus viscosity of preferably 30,000 dPa ⁇ s or more, more preferably 40,000 dPa ⁇ s or more, and further preferably 50,000 dPa ⁇ s or more. By being in these ranges, devitrification crystals are less likely to occur at the time of molding, and it becomes easy to mold a glass substrate by the overflow downdraw method.
  • the glass substrate of the present invention has a Young's modulus of preferably 70 GPa or more, more preferably 73 GPa or more, still more preferably 74 GPa or more, and even more preferably 75 GPa or more. If the Young's modulus (GPa) is small, the glass tends to break due to the bending of the glass due to its own weight.
  • the Young's modulus (GPa) of the glass substrate has a strong tendency to fluctuate the Young's modulus (GPa) in the range of the composition of the glass substrate of the present invention, for example, by increasing the content of Al 2 O 3 etc. can do.
  • the specific elastic modulus (Young's modulus / density) of the glass substrate of the present invention is preferably 28 or more, more preferably 29 or more, still more preferably 30 or more, and still more preferably 31 or more.
  • the specific elastic modulus is small, the glass is easily broken due to the bending of the glass due to its own weight.
  • a glass ribbon is formed from the melted and clarified molten glass by the overflow down draw method.
  • the overflow downdraw method is a known method.
  • JP 2009-298665 A, JP 2010-215428 A, JP 2011-168494 A, and the like can be referred to, and the entire description thereof is specifically incorporated herein by reference. Is done.
  • An explanatory diagram of an apparatus used in the overflow downdraw method is shown in FIGS.
  • FIG. 1 and 2 show a schematic configuration of a molding apparatus 40 used in the overflow downdraw method.
  • FIG. 1 is a cross-sectional view of the molding apparatus 40.
  • FIG. 2 is a side view of the molding apparatus 40.
  • the forming apparatus 40 has a passage through which the glass ribbon GR passes and a space surrounding the passage.
  • the space surrounding the passage is composed of an overflow chamber 20, a forming chamber 30, and a cooling chamber 80.
  • the molding apparatus 40 mainly includes a molded body 41, a partition member 50, a cooling roller 51, a temperature adjustment unit 60, lowering rollers 81a to 81d, heaters 82a to 82h, and a cutting device 90. . Furthermore, the shaping
  • the overflow chamber 20 is a space for forming molten glass sent from a refining device (not shown) into the glass ribbon GR. By adopting the overflow downdraw method, a polishing step of the glass substrate surface after molding becomes unnecessary.
  • Cooling step (3) the glass ribbon molded in the molding step is cooled under the following condition (A).
  • the formed glass ribbon is cooled while being drawn downward.
  • General methods and conditions for drawing and cooling the glass ribbon are already known.
  • the glass ribbon formed in the overflow molding apparatus is subjected to online annealing for cooling as it is, and further cut to produce a glass plate.
  • the forming chamber 30 is disposed below the overflow chamber 20 and is a space for adjusting the thickness and the amount of warpage of the glass ribbon GR.
  • a part of the first cooling step S41 described later is executed. Specifically, in the forming chamber 30, the upstream region of the glass ribbon GR is cooled.
  • the upstream region of the glass ribbon GR is a region of the glass ribbon GR where the temperature of the central portion C of the glass ribbon GR is above the annealing point.
  • the center portion C of the glass ribbon GR is the center in the width direction of the glass ribbon GR.
  • the upstream region includes a temperature region until the temperature of the central portion C of the glass ribbon GR becomes near the annealing point.
  • the glass ribbon GR passes through a cooling chamber 80 described later.
  • the cooling chamber 80 shown in FIGS. 1 and 2 is a space for adjusting the strain amount of the glass ribbon GR, which is disposed below the overflow chamber 20 and the forming chamber 30.
  • a part of a first cooling step S41, a second cooling step S42, and a third cooling step S43, which will be described later, are executed.
  • the glass ribbon GR that has passed through the forming chamber 30 is cooled to a temperature in the vicinity of room temperature via a slow cooling point and a strain point.
  • the inside of the cooling chamber 80 is divided into a plurality of spaces by a heat insulating member 80b.
  • the cooling process of the glass ribbon is a first cooling process in which the glass ribbon formed in the overflow molding apparatus at about 1,100 ° C. to 1,250 ° C. is cooled to the annealing point, from the annealing point (strain point ⁇ 50 ° C. ) And a third cooling step for cooling from a temperature below (strain point ⁇ 50 ° C.) to a temperature near (strain point ⁇ 200 ° C.). Furthermore, in the present invention, the average cooling rate at the center of the glass ribbon in the second cooling step is 0.5 to less than 5.5 ° C./second (Condition A).
  • the cooling rate of the glass ribbon means the average cooling rate at the center of the glass ribbon unless otherwise specified.
  • strain point ⁇ 50 ° C. means a temperature 50 ° C. lower than the strain point
  • strain point ⁇ 200 ° C. means a temperature 200 ° C. lower than the strain point.
  • the cooling step of the molded glass ribbon in the production method of the present invention can satisfy the condition (D) in addition to satisfying the condition (A) or (A) to (C).
  • (D) The average cooling rate until the temperature of the glass ribbon becomes less than the (strain point ⁇ 50 ° C.) to the (strain point ⁇ 200 ° C.) is as follows. 50 ° C.) faster than the average cooling rate.
  • Condition (B) is the cooling condition in the first cooling step until the temperature of the glass ribbon reaches the annealing point, and the average cooling rate at the center of the glass ribbon formed in the forming step: 5.5 ° C./second or more And
  • the average cooling rate at the center of the glass ribbon in the first cooling step is preferably 5.5 ° C./second to 50.0 ° C./second, more preferably 8.0 ° C./second to 16.5 ° C./second. It is. If the average cooling rate at the center of the glass ribbon in the first cooling step is less than 5.5 ° C./second, the productivity will be reduced.
  • the first ear cooling rate in the first cooling step S41 is preferably 5.5 ° C./second to 52.0 ° C./second, more preferably 8.3 ° C./second to 17.5 ° C./second. Seconds. Moreover, it is preferable that the average cooling rate of the glass ribbon center part in a 1st cooling process is quicker than the average cooling rate of the glass ribbon center part in a 2nd cooling process and a 3rd cooling process.
  • Condition (C) is that the average cooling rate in the first cooling step until the temperature of the glass ribbon reaches the annealing point is that the temperature of the glass ribbon is less than (strain point ⁇ 50 ° C.) (strain point ⁇ 200 ° C.). It is faster than the average cooling rate in the third cooling step until.
  • Condition (A) is the cooling condition of the glass ribbon in the second cooling step, and the average cooling rate at the center of the glass ribbon from the annealing point to the temperature of (strain point ⁇ 50 ° C.) is 0.5 to 5.5.
  • the temperature is less than ° C./second, preferably 1.0 ° C./second to 5.5 ° C./second, more preferably 1.5 ° C./second to 5.0 ° C./second. If the average cooling rate of the glass ribbon center part in a 2nd cooling process is less than 0.5 degree-C / sec, a manufacturing facility will become huge and productivity will fall. On the other hand, at 5.5 ° C./second or more, the heat shrinkage rate cannot be sufficiently reduced.
  • the ear part cooling rate in the second cooling step is preferably 0.3 ° C./second to 5.3 ° C./second, more preferably 0.8 ° C./second to 2.8 ° C./second. Moreover, it is preferable that the average cooling rate of the glass ribbon center part in a 2nd cooling process is slower than the average cooling rate of the glass ribbon center part in a 1st cooling process.
  • the cooling rate of the central portion of the glass ribbon in the third cooling step is not particularly limited, but is preferably 1.5 ° C./second to 7.0 ° C./second, more preferably 2.0 ° C. ° C / sec to 5.5 ° C / sec. If the cooling rate at the center of the glass ribbon in the third cooling step is less than 1.5 ° C./second, the productivity will be lowered. On the other hand, at 7.0 ° C./second or more, the glass ribbon may be broken due to the rapid cooling of the glass.
  • the ear cooling rate in the third cooling step S43 is preferably 1.3 ° C./second to 6.8 ° C./second, more preferably 1.5 ° C./second to 5.0 ° C./second. .
  • the average cooling rate of the glass ribbon center part in the third cooling step can be faster than the average cooling rate of the glass ribbon center part in the second cooling step.
  • Condition (D) is that the temperature of the glass ribbon is gradually decreased in the third cooling step until the temperature of the glass ribbon becomes less than (strain point ⁇ 50 ° C.) to (strain point ⁇ 200 ° C.). It is faster than the average cooling rate in the second cooling step from the cold spot to (strain point ⁇ 50 ° C.).
  • the average cooling rate in the third cooling step until the temperature of the glass ribbon is less than the above (strain point ⁇ 50 ° C.) to the above (strain point ⁇ 200 ° C.) is the temperature of the glass ribbon from the annealing point ( Even if it is slower than the average cooling rate in the second cooling step until the strain point reaches ⁇ 50 ° C., if the above conditions (A) to (C) are satisfied, the temperature control in the width direction of the glass ribbon can be performed with the desired accuracy. It can be carried out. Satisfying the condition (D) further increases the accuracy.
  • the sheet glass SG it is preferable to cool the sheet glass SG at different cooling rates at least in the cooling steps S41 and S42 in the three cooling steps S41 to S43 included in the cooling step S4 of the glass ribbon GR.
  • Either of the cooling rates of the cooling steps S42 and S43 may be faster.
  • the cooling rate of the first cooling step S41 is the fastest, and the cooling rate of the second cooling step S42 and the cooling rate of the third cooling step S43 are either fast.
  • FIG. 3 shows a temperature profile at a predetermined height position of the glass ribbon GR.
  • FIG. 4 shows the cooling rate of the glass ribbon GR (0.7 mm) manufactured in Example 1 that satisfies the condition (D).
  • the first cooling step S41 is a step of cooling the molten glass joined immediately below the molded body 41 to a temperature near the annealing point. Specifically, in the first cooling step, the glass ribbon GR of about 1,100 ° C. to 1,250 ° C. is cooled to a temperature near the annealing point (see FIG. 4).
  • the annealing point is the temperature at which the viscosity is 10 13 dPa ⁇ s.
  • the temperature management of the glass ribbon GR is performed based on the first temperature profile TP1 to the fourth temperature profile TP4.
  • the temperature of the end portion in the width direction of the glass ribbon GR is lower than the temperature of the central region CA sandwiched between the end portions, and the temperature of the central region CA is uniform.
  • the second temperature control step is included in which the temperature in the width direction of the glass ribbon GR is lowered from the central portion toward the end portion.
  • the temperature of the central area CA is uniform means that the temperature of the central area CA is included in a predetermined temperature range.
  • the predetermined temperature range is a range of the reference temperature ⁇ 20 ° C.
  • the reference temperature is an average temperature in the width direction of the central area CA.
  • a gradient (temperature gradient) is formed between the temperature of the central portion C and the temperatures of the ear portions R and L.
  • the temperature gradient is a value obtained by dividing the width W (for example, 1650 mm, see FIG. 3) of the glass ribbon GR by 2, and the temperatures of the ears R and L are subtracted from the temperature of the center C. The value is divided by ((temperature of center C-temperature of ears R and L) / (width W / 2 of sheet glass)).
  • the first temperature profile TP1 shown in FIG. Specifically, the ears R and L of the glass ribbon GR are cooled by the cooling roller 51.
  • the temperature of the ear portions R and L of the glass ribbon GR is cooled to a temperature lower than the temperature of the central area CA by a predetermined temperature (for example, 200 ° C. to 250 ° C.).
  • the first temperature profile TP1 suppresses the shrinkage of the glass ribbon GR in the width direction by rapidly cooling the ear portion, and makes the thickness of the glass ribbon GR uniform.
  • the second temperature profile TP2 and the third temperature profile TP3 are realized by controlling the temperature adjustment unit 60 in the forming chamber 30. Specifically, the ears R and L of the glass ribbon GR are cooled by the cooling units 64 and 65, and the central area CA of the sheet glass is cooled by the cooling units 62 and 63. By performing such cooling, tension can always be applied at the center of the glass ribbon GR, and warping of the glass ribbon GR can be suppressed.
  • the fourth temperature profile TP4 is realized by controlling the heater 82a in the cooling chamber 80.
  • tension can always be applied at the center of the glass ribbon GR, and the warp of the glass ribbon GR can be reduced. Can be suppressed.
  • the second cooling step S42 is a step of cooling the glass ribbon GR that has reached a temperature near the annealing point to a temperature near the strain point of ⁇ 50 ° C. (see FIG. 4).
  • the strain point is a temperature at which the viscosity of the glass is 10 14.5 dPa ⁇ s.
  • the second cooling step S42 the temperature management of the glass ribbon GR is performed based on the fifth temperature profile TP5 and the sixth temperature profile TP6.
  • the second cooling step includes a third temperature control step in which the temperature gradient between the end portion in the width direction and the center portion of the sheet glass decreases as the vicinity of the glass strain point is approached.
  • the fifth temperature profile TP5 is realized by controlling the heater 82b in the cooling chamber 80.
  • the temperature gradient TG5 in the fifth temperature profile TP5 smaller than the temperature gradient TG4 in the upstream fourth temperature profile TP4, it is possible to always apply tension at the center of the glass ribbon GR, and to warp the glass ribbon GR. Can be suppressed.
  • the sixth temperature profile TP6 has a uniform temperature in the width direction of the glass ribbon GR (temperature from the ear portions R and L in the width direction to the center portion C).
  • the sixth temperature profile TP6 has the smallest temperature gradient between the temperature around the ears R and L and the temperature around the center C in the width direction of the glass ribbon GR, and the temperature around the ears R and L. This is a temperature profile in which the temperature around the central portion C is approximately the same.
  • uniform means that the temperature around the ears R and L and the temperature around the center C are included in a predetermined temperature range.
  • the predetermined temperature range is a range of reference temperature ⁇ 5 ° C.
  • the reference temperature is an average temperature in the width direction of the glass ribbon GR.
  • the sixth temperature profile TP6 is realized by controlling the heater 82c in the cooling chamber 80.
  • the sixth temperature profile TP6 is realized in the vicinity of the strain point.
  • the vicinity of the strain point means a predetermined temperature region including the strain point.
  • the predetermined temperature region is a region from “(annealing point + strain point) / 2” to “strain point ⁇ 50 ° C.”.
  • the sixth temperature profile TP6 is realized at at least one point (one place in the flow direction) near the strain point.
  • the third cooling step S43 is a step of cooling the glass ribbon GR having a temperature near the strain point ⁇ 50 ° C. to a temperature near the strain point ⁇ 200 ° C. (see FIG. 4). ).
  • the temperature management of the glass ribbon GR is performed based on the seventh temperature profile TP7 to the tenth temperature profile TP10.
  • a fourth temperature control step is included in which the temperature in the width direction of the sheet glass is lowered from the end portion in the width direction of the sheet glass toward the center portion.
  • the glass ribbon is lowered from the both end portions (ear portions) of the glass ribbon toward the central portion. It is preferable to control the temperature.
  • the seventh temperature profile TP7 to the tenth temperature profile TP10 are realized by controlling the heaters 82d to 82g in the cooling chamber 80. Specifically, the heater 82d implements the seventh temperature profile TP7, the heater 82e implements the eighth temperature profile TP8, the heater 82f implements the ninth temperature profile TP9, and the heater 82g implements the tenth temperature profile TP10. Realized.
  • the temperature of the central portion C of the central area CA is the lowest, the temperatures of the ears R and L are the highest, and the temperature gradients TG7 to TG10 in the seventh temperature profile TP7 to the tenth temperature profile TP10 are changed in the flow direction of the glass ribbon GR. By gradually increasing the width along the direction, tension can always be applied at the center of the glass ribbon GR, and warpage of the glass ribbon GR can be suppressed.
  • At least the temperature in the central portion in the width direction of the glass ribbon is glass so that tension acts in the transport direction of the glass ribbon in the central portion in the width direction of the glass ribbon.
  • the temperature can be controlled so that the cooling rate is faster than the cooling rate at both ends in the width direction.
  • both ends in the width direction of the glass ribbon are the both ends. Controlling the temperature of the glass ribbon so that it is lower than the temperature of the central part sandwiched between the parts and the temperature of the central part is uniform, (2) in the central part in the width direction of the glass ribbon, In the region where the temperature of the central portion of the glass ribbon is less than the glass softening point and the glass strain point or higher so that the tension in the ribbon conveyance direction works, the temperature distribution in the width direction of the glass ribbon extends from the central portion toward the both end portions.
  • the temperature of the glass ribbon is controlled to be low, and (3) in the temperature region where the temperature of the central portion of the glass ribbon becomes a glass strain point, It is preferable to control the temperature of the glass ribbon so that the temperature gradient between the central portion and the both end portions of the direction is eliminated.
  • Example 1 (Production of sample glass) In order to obtain the glass composition shown in Table 1, silica, alumina, boron oxide, potassium carbonate, basic magnesium carbonate, calcium carbonate, strontium carbonate, stannic oxide and ferric trioxide, which are ordinary glass raw materials, are used. A glass raw material batch (hereinafter referred to as a batch) was prepared.
  • the blended batch is melted at 1560-1640 ° C., clarified at 1620-1670 ° C., and clarified at 1440-1530 ° C. using a continuous melting apparatus equipped with a refractory brick melting tank and a platinum alloy adjustment tank.
  • the glass ribbon GR has a width of 1600 mm and is formed into a thin plate with a thickness of 0.7 mm by the overflow down draw method.
  • Slow cooling was performed under the conditions to obtain a glass substrate for liquid crystal display (for organic EL display).
  • the predetermined slow cooling conditions are shown in Tables 2-6.
  • the glass substrate for a test of 30 mm x 40 mm x 0.7 mm was produced from the glass substrate obtained on the slow cooling conditions of Table 3.
  • strain point and annealing point Measurement was performed using a beam bending measuring apparatus (manufactured by Tokyo Kogyo Co., Ltd.), and the strain point and annealing point were determined by calculation according to the beam bending method (ASTM C-598).
  • Heat shrinkage The heat shrinkage rate was raised from room temperature at 10 ° C / min, held at 550 ° C for 1 hour, then lowered to room temperature at 10 ° C / min, raised again at 10 ° C / min, and 1 at 550 ° C.
  • Thermal shrinkage (ppm) ⁇ Shrinkage amount of glass before and after heat treatment / length of glass before heat treatment ⁇ ⁇ 10 6
  • the amount of shrinkage was measured by the following method.
  • the glass substrate was pulverized and passed through a 2380 ⁇ m sieve to obtain glass particles that remained on the 1000 ⁇ m sieve.
  • the glass particles were immersed in ethanol, subjected to ultrasonic cleaning, and then dried in a thermostatic bath.
  • the dried glass particles were placed on a platinum boat having a width of 12 mm, a length of 200 mm, and a depth of 10 mm so that the glass particles had a substantially constant thickness.
  • This platinum boat was kept in an electric furnace having a temperature gradient of 1080 to 1320 ° C. for 5 hours, and then removed from the furnace, and devitrification generated in the glass was observed with a 50 ⁇ optical microscope.
  • the maximum temperature at which devitrification was observed was defined as the devitrification temperature.
  • a differential thermal dilatometer (Thermo Plus2 TMA8310) was used to measure the temperature and the amount of glass expansion and contraction during the temperature raising process. The heating rate at this time was 5 ° C./min. Based on the measurement results of the temperature and the amount of expansion and contraction of the glass, the average thermal expansion coefficient and Tg in the temperature range of 100 to 300 ° C. were measured.
  • the density of the glass was measured by the Archimedes method using the Young's modulus measurement sample. (Young's modulus and specific modulus) The Young's modulus was measured by an ultrasonic pulse method after preparing a glass having a thickness of 5 mm. The specific elastic modulus was calculated from Young's modulus and density.
  • the melting temperature was obtained by calculating the temperature at a viscosity of 102.5 dPa ⁇ s from the measurement result using a platinum ball pull-up type automatic viscosity measuring device.
  • the liquid phase viscosity was obtained by calculating the viscosity at the devitrification temperature from the above measurement result.
  • Tables 2 to 5 show the actual value of the temperature change (° C.) and the time required for the temperature change (seconds) of the glass ribbon GR and the average cooling rate (° C./second) of the central portion C of the glass ribbon GR in the cooling step S4. Indicates. Tables 2 to 5 show that the average cooling rate (° C./second) in S42 (temperature range from annealing point to strain point ⁇ 50 ° C.) is 0.9, 1.1, 2.9, and 5. The value at 1 is shown. Further, Table 8 shows the thermal contraction rate of the manufactured glass substrate when the average cooling rate (° C./second) in S42 is 0.9, 1.1, 2.9, and 5.1, respectively. Show.
  • Example 2 Glass composition (mol%), devitrification temperature (° C), annealing point (° C), strain point (° C), average thermal expansion coefficient ( ⁇ 10 -7 ° C -1 ), density (g / cm 3 ), The Young's modulus (GPa), specific elastic modulus, melting temperature (° C.), liquid phase viscosity (dPa ⁇ s), Tg (° C.) and specific resistance ( ⁇ ⁇ cm) are as shown in Table 1. Moreover, the width
  • Tables 6 to 7 show the actual value of the temperature change (° C.) and the time required for the temperature change (seconds) of the glass ribbon GR and the average cooling rate (° C./second) of the center C of the glass ribbon GR in the cooling step S4. Indicates. Tables 6 to 7 show values when the average cooling rate (° C./second) in S42 is 2.1 and 3.0, respectively. Furthermore, in Table 8, the thermal contraction rate of the manufactured glass substrate in case the average cooling rate (degreeC / sec) in S42 is 2.1 and 3.0, respectively.
  • Comparative Example Glass composition (mol%), devitrification temperature (° C), annealing point (° C), strain point (° C), average thermal expansion coefficient ( ⁇ 10 -7 ° C -1 ), density (g / cm 3 ), Young's modulus (GPa), specific elastic modulus, melting temperature (° C.), liquid phase viscosity (dPa ⁇ s), Tg (° C.) and specific resistance ( ⁇ ⁇ cm) are as shown in Table 1.
  • variety of the glass ribbon GR shall be 1600 mm, and thickness was 0.7 mm.
  • Table 9 shows actual values of temperature change (° C.) and time (seconds) required for the temperature change of the glass ribbon GR in the cooling step S4, and annealing points (715 ° C.) and strain points interpolated based on the actual values.
  • a value (interpolated value) relating to a time until reaching ⁇ 50 ° C. (610 ° C.) and a strain point of ⁇ 200 ° C. (460 ° C.) and a cooling rate (° C./second) of the center C are shown.
  • the cooling rate in the first cooling step S41 is the largest value
  • the cooling rate in the third cooling step S43 is the next largest value
  • the cooling rate in the second cooling step S42 is the smallest value.
  • a cooling step was performed. As shown in Table 8, the thermal contraction rate of the obtained glass substrate was 86 ppm.

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PCT/JP2012/074706 2011-09-30 2012-09-26 フラットパネルディスプレイ用ガラス基板の製造方法 WO2013047585A1 (ja)

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CN107188406A (zh) * 2016-03-15 2017-09-22 旭硝子株式会社 无碱玻璃基板和无碱玻璃基板的制造方法
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TWI722998B (zh) * 2014-09-25 2021-04-01 日商日本電氣硝子股份有限公司 支撐玻璃基板、積層體、半導體封裝體的製造方法、半導體封裝體、電子設備
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CN107188406A (zh) * 2016-03-15 2017-09-22 旭硝子株式会社 无碱玻璃基板和无碱玻璃基板的制造方法
WO2018156887A1 (en) * 2017-02-24 2018-08-30 Corning Incorporated Dome or bowl shaped glass and method of fabricating dome or bowl shaped glass
WO2023022052A1 (ja) * 2021-08-17 2023-02-23 日本電気硝子株式会社 ガラス物品の製造方法及び製造装置

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