Alkali-free glass substrate, laminated substrate, and glass substrate production method
AssigneeAGC Inc.
InventorsShuhei NOMURA, Kazutaka ONO
Life of this patent
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Abstract
An alkali-free glass substrate which is a glass substrate includes, as represented by molar percentage based on oxides, 0.1% to 10% of ZnO. The alkali-free glass substrate has an average coefficient of thermal expansion α50/100 at 50 to 100° C. of from 2.70 ppm/° C. to 3.20 ppm/° C., an average coefficient of thermal expansion α200/300 at 200 to 300° C. of from 3.45 ppm/° C. to 3.95 ppm/° C., and a value α200/300/α50/100 obtained by dividing the average coefficient of thermal expansion α200/300 at 200 to 300° C. by the average coefficient of thermal expansion α50/100 at 50 to 100° C. of from 1.20 to 1.30.
Claims15
An alkali-free glass substrate which is a glass substrate comprising, as represented by molar percentage based on oxides,
- 0.1% to 10% of ZnO,
- and having an average coefficient of thermal expansion α50/100 at 50 to 100° C. of from 2.70 ppm/° C. to 3.20 ppm/° C.,
- an average coefficient of thermal expansion α200/300 at 200 to 300° C. of from 3.45 ppm/° C. to 3.95 ppm/° C., and
- a value α200/300/α50/100 obtained by dividing the average coefficient of thermal expansion α200/300 at 200 to 300° C. by the average coefficient of thermal expansion α50/100 at 50 to 100° C. of from 1.20 to 1.30.
A method for manufacturing an alkali-free glass substrate comprising:
- a melting step of heating glass raw materials to obtain a molten glass;
- a forming step of forming the molten glass into a sheet-like shape to obtain a glass ribbon;
- and
- a slow cooling step of gradually cooling the glass ribbon to a room temperature state,
- wherein an obtained glass substrate has the following composition as represented by molar percentage based on oxides:
- SiO2:
- from 50% to 75%,
- Al2O3:
- from 6% to 16%,
- B2O3:
- from 0% to 15%,
- MgO:
- from 0% to 15%,
- CaO:
- from 0% to 13%,
- SrO:
- from 0% to 11%,
- BaO:
- from 0% to 9.5%, and
- ZnO:
- from 0.1% to 10%, and
- the composition of the obtained glass substrate and an average cooling rate R (unit:
- ° C./min) from a temperature at which the viscosity of the glass ribbon becomes 1013 dPa·s to a temperature at which the viscosity becomes 1014.5 dPa·s in the slow cooling step satisfy the following conditions (1), (2), (3), and (4):
- 0.0177×(content of SiO2)−0.0173×(content of Al2O3)+0.0377×(content of B2O3)+0.0771×(content of MgO)+0.1543×(content of CaO)+0.1808×(content of SrO)+0.2082×(content of BaO)+0.0396×(content of ZnO)+0.0344×log10 R is from 2.70 to 3.20 Condition (1):
- 0.0181×(content of SiO2)+0.0004×(content of Al2O3)+0.0387×(content of B2O3)+0.0913×(content of MgO)+0.1621×(content of CaO)+0.1900×(content of SrO)+0.2180×(content of BaO)+0.0424×(content of ZnO)+0.0391×log10 R is 3.13 to 3.63 Condition (2):
- 0.0177×(content of SiO2)+0.0195×(content of Al2O3)+0.0323×(content of B2O3)+0.1015×(content of MgO)+0.1686×(content of CaO)+0.1990×(content of SrO)+0.2179×(content of BaO)+0.0493×(content of ZnO)+0.0312×log10 R is 3.45 to 3.95 Condition (3):
- 0.0111×(content of SiO2)+0.0250×(content of Al2O3)+0.0078×(content of B2O3)+0.0144×(content of MgO)+0.0053×(content of CaO)+0.0052×(content of SrO)+0.0013×(content of BaO)+0.0121×(content of ZnO)−0.0041×log10 R is 1.20 to 1.30, Condition (4):
- wherein in the conditions (1) to (4), the contents of SiO2, Al2O3, B2O3, MgO, CaO, SrO, BaO, and ZnO are contents contained in a obtained glass as represented by molar percentage based on oxides.
Dependencies are inferred from the claim text.