Chemically strengthened glass, method for producing same, and glass for chemical strengthening
AssigneeAGC Inc.
InventorsKenji IMAKITA, Suguru MURAYAMA
Life of this patent
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Abstract
A plate-like chemically strengthened glass having a compression stress layer on the surface of the glass, wherein the compressive stress value (CS0) at the glass surface of is 500 MPa or more, the plate thickness (t) is 400 μm or more, the compressive stress depth of layer (DOL) is (t×0.15) μm or more, the compressive stress values (CS1) and (CS2) when the depth from the glass surface is ¼ and ½, respectively, are 50 MPa or more, m1 expressed by {m1=(CS1−CS2/(DOL/4−DOL/2)} is −1.5 MPa/μm or more, m2 expressed by {m2=(CS2/(DOL/2−DOL)} is 0 MPa/μm or less, and m2 is less than m1.
Claims12
A chemically strengthened glass having a sheet shape and having a compressive stress layer in a glass surface, wherein:
- the glass surface has a compressive stress value (CS0) of 500 MPa or higher;
- a sheet thickness (t) is 400 μm or larger;
- a depth of the compressive stress layer (DOL) is (t×0.15) μm or larger;
- a compressive stress value (CS1) measured at a point lying at a depth of ¼ of the DOL from the glass surface is 50 MPa or higher;
- a compressive stress value (CS2) measured at a point lying at a depth of ½ of the DOL from the glass surface is 50 MPa or higher;
- a value of m1 represented by the following expression is −0.2 MPa/μm or less, and a value of m2 represented by the following expression is 0 MPa/μm or less:
- m1=(CS1−CS2)/(DOL/4−DOL/2),
- m2=CS2/(DOL/2−DOL);
- and
- a value of m3 represented by the following expression is 120 MPa/μm or larger, with respect to a compressive stress value (CS3) measured at a point lying at a depth from the glass surface of 2.5 μm:
- m3=(CS0−CS3)/2.5;
- and
- the chemically strengthened glass has a base composition comprising, in mass percentage on an oxide basis:
- 50-70% of SiO2;
- 15-28% of Al2O3;
- 0-10% of B2O3;
- 2-8% of Li2O;
- 1-8% of Na2O;
- 0-9% of K2O;
- 0-5% of (MgO+CaO+SrO+BaO);
- and
- 0-3% of (ZrO2+TiO2).
A chemically strengthened glass having a sheet shape and having a compressive stress layer in a glass surface, wherein:
- the glass surface has a compressive stress value (CS0) of 500 MPa or higher;
- a depth of the compressive stress layer (DOL) is 100 μm or larger;
- a compressive stress value (CS1) measured at a point lying at a depth of ¼ of the DOL from the glass surface is 50 MPa or higher;
- a compressive stress value (CS2) measured at a point lying at a depth of ½ of the DOL from the glass surface is 50 MPa or higher;
- and
- a value of m represented by the following expression is −0.2 MPa/μm or less, and a value of m2 represented by the following expression is 0 MPa/μm or less:
- m1=(CS1−CS2)/(DOL/4−DOL/2),
- m2=CS2/(DOL/2−DOL);
- and
- the chemically strengthened glass has a base composition comprising, in mass percentage on an oxide basis:
- 50-70% of SiO2;
- 15-28% of Al2O3;
- 0-10% of B2O3;
- 2-8% of Li2O;
- 1-8% of Na2O;
- 0-9% of K2O;
- 0-5% of (MgO+CaO+SrO+BaO);
- and
- 0-3% of (ZrO2+TiO2).
Dependencies are inferred from the claim text.