Cover glass and method for producing same
AssigneesAvanStrate Inc., Hoya Corporation
InventorsAkihiro Koyama, Satoshi Ami, Kazuaki Hashimoto, Tetsuo Takano
Life of this patent
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Abstract
A cover glass having a compressive-stress layer on the principal surfaces thereof, and having a glass composition containing 50% to 70% by mole of SiO2, 3% to 20% by mole of Al2O3, 5% to 25% by mole of Na2O, more than 0% by mole and less than or equal to 2.5% by mole of Li2O, 0% to 5.5% by mole of K2O, and 0% to less than 3% by mole of B2O3. Also disclosed is a method for producing a cover glass which includes: (i) preparing molten glass by melting a glass raw material; (ii) forming the prepared molten glass into a plate-like shape by a down-draw process and thereby obtaining a glass substrate; and (iii) forming a compressive-stress layer on the surface of the glass substrate.
Claims24
A cover glass comprising a compressive-stress layer on principal surfaces thereof, the cover glass having a glass composition containing
- 50% to 70% by mole of SiO2,
- 3% to 20% by mole of Al2O3,
- 5% to 25% by mole of Na2O,
- more than 0% by mole and less than or equal to 2.5% by mole of Li2O,
- 0% to 5.5% by mole of K2O,
- 0% to less than 3% by mole of B2O3, and
- more than or equal to 0.11% by mole of MgO/(Li2O+Na2O+K2O),
- wherein the glass composition does not substantially contain As2O3 and Sb2O3.
A strengthened glass comprising a compressive-stress layer on principal surfaces thereof, the strengthened glass having a glass composition containing
- 50% to 70% by mole of SiO2,
- 3% to 20% by mole of Al2O3,
- 5% to 25% by mole of Na2O,
- more than 0% by mole and less than or equal to 2.5% by mole of Li2O,
- 0% to 5.5% by mole of K2O,
- 0% to less than 3% by mole of B2O3, and
- more than or equal to 0.11% by mole of MgO/(Li2O+Na2O+K2O),
- wherein the glass composition does not substantially contain As2O3 and Sb2O3.
A cover glass comprising a compressive-stress layer on principal surfaces thereof, the cover glass having a glass composition containing
- 45% to 70% by mass of SiO2,
- 5% to 25% by mass of Al2O3,
- 9% to 25% by mass of Na2O,
- more than 0% by mass and less than or equal to 2.5% by mass of Li2O,
- 0% to 3% by mass of B2O3,
- more than 0% by mass and less than or equal to 10% by mass of MgO, and
- more than or equal to 0.11% by mole of MgO/(Li2O+Na2O+K2O),
- wherein the compressive-stress layer has a surface stress depth of 30 μm or greater, and wherein the glass composition does not substantially contain As2O3 and Sb2O3.
Dependencies are inferred from the claim text.