Glass substrate and method for producing same
AssigneeAsahi Glass Company, Limited
InventorManabu NISHIZAWA
Life of this patent
Estimating the term…
Abstract
A glass substrate contains specific contents of SiO2, Al2O3, B2O3, MgO, CaO, SrO, BaO, ZrO2, Na2O, K2O and Li2O. The glass substrate has a glass transition temperature of 580 to 720° C., an average coefficient of thermal expansion at 50 to 350° C. of 65×10−7 to 85×10−7/° C., a compaction (C) of 15 ppm or less, a glass surface devitrification temperature Tc of 900 to 1,300° C., a glass internal devitrification temperature Td of 900 to 1,300° C., a temperature T4 at which a viscosity reaches 104 dPa·s of 1,100 to 1,350° C., a relationship (T4−Tc) of −50 to 350° C. and a relationship (T4−Td) of −50 to 350° C.
Claims10
A glass substrate containing, in terms of mol % on the basis of the following oxides:
- from 60 to 79% of SiO2;
- from 2.5 to 18% of Al2O3;
- from 0 to 3% of B2O3;
- from 1 to 15% of MgO;
- from 0 to 1% of CaO;
- from 0 to 1% of SrO;
- from 0 to 1% of BaO;
- from 0 to 1% of ZrO2;
- from 7 to 15.5% of Na2O;
- from 0 to 3% of K2O;
- and
- from 0 to 2% of Li2O;
- wherein Na2O+K2O is from 7 to 15.5%,
- Na2O/(Na2O+K2O) is from 0.77 to 1,
- MgO+CaO+SrO+BaO is from 1 to 18%,
- MgO−0.5Al2O3 is from 0 to 10, and
- MgO+0.5Al2O3 is from 1 to 20,
- wherein the glass substrate has:
- a glass transition temperature of from 580 to 720° C.;
- an average coefficient of thermal expansion within a range of from 50 to 350° C. of from 65×10−7 to 85×10−7/° C.;
- a compaction (C) of 15 ppm or less;
- a glass surface devitrification temperature (Tc) of from 900 to 1,300° C.;
- a glass internal devitrification temperature (Td) of from 900 to 1,300° C.;
- a temperature (T4) at which a viscosity reaches 104 dPa·s of from 1,100 to 1,350° C.;
- a relationship (T4−Tc) between the temperature (T4) at which a viscosity reaches 104 dPa·s and the glass surface devitrification temperature (Tc) of from −50 to 350° C.;
- and
- a relationship (T4−Td) between the temperature (T4) at which a viscosity reaches 104 dPa·s and the glass internal devitrification temperature (Td) of from −50 to 350° C.
Dependencies are inferred from the claim text.