Chemically strengthened glass
The present invention relates to a chemically strengthened glass satisfying A 1 [MPa] of 600 or more, A 2 [MPa] of 50 or more, B 1 [μm] of 6 or less, B 2 [μm] of 10% or more of t [μm], C [MPa] of −30 or less, and A 1 /B 1 [MPa/μm] of 100 or more when the chemically strengthened glass has a thickness t [μm] and a profile of a stress value [MPa] at a depth x [μm] from a glass surface is approximated by an error least-squares method in a region of 0<x<3t/8 using the following function while defining a compressive stress as positive and a tensile stress as negative: A 1 erfc(x/B 1 )+A 2 erfc(x/B 2 )+C, in which erfc is a complementary error function, and relations of A 1 >A 2 and B 1 <B 2 are satisfied.
1. A chemically strengthened glass satisfying A 1 [MPa] of 600 or more, A 2 [MPa] of 50 or more, B 1 [μm] of 6 or less, B 2 [μM] of 10% or more of t [μm], C [MPa] of −30 or less, A 1 /B 1 [MPa/μm] of 100 or more, and A 2 /B 2 [MPa/μm] of 1.9 or less when the chemically strengthened glass has a thickness t [μm] and a profile of a stress value [MPa] at a depth x [μm] from a glass surface is approximated by an error least-squares method in a region of 0<x<3t/8 using the following function (I) while defining a compressive stress as positive and a tensile stress as negative:
A 1 erfc(x/B 1 )+A 2 erfc(x/B 2 )+C (I),
wherein erfc is a complementary error function, and relations of A 1 >A 2 and B 1 <B 2 are satisfied,
the chemically strengthened glass having a base composition comprising 50 to 80% of SiO 2 , 4 to 30% of Al 2 O 3 , 0 to 15% of B 2 O 3 , 0 to 15% of P 2 O 5 , 0 to 20% of MgO, 0 to 20% of CaO, 0 to 10% of SrO, 0 to 10% of BaO, 0 to 10% of ZnO, 0 to 10% of TiO 2 , 0 to 10% of ZrO 2 , 3 to 20% of Li 2 O, 0 to 20% of Na 2 O, and 0 to 20% of K 2 O in mole percentage on an oxide basis.
2. The chemically strengthened glass according to claim 1 , wherein B 2 [μm] is 20% or more of t [μm].
3. The chemically strengthened glass according to claim 1 , wherein A 2 [MPa] is 150 or more.
4. The chemically strengthened glass according to claim 1 , wherein C [MPa] is −70 or less.
5. The chemically strengthened glass according to claim 1 , wherein the thickness t is 0.3 mm or more and 2 mm or less.
6. The chemically strengthened glass according to claim 1 , having a base composition comprising 50 to 80% of SiO 2 , 4 to 30% of Al 2 O 3 , 0 to 15% of B 2 O 3 , 0 to 15% of P 2 O 5 , 0 to 20% of MgO, 0 to 20% of CaO, 0 to 10% of SrO, 0 to 10% of BaO, 0 to 10% of ZnO, 0 to 10% of TiO 2 , 0 to 10% of ZrO 2 , 3 to 20% of Li 2 O, 0 to 20% of Na 2 O, 0 to 20% of K 2 O, and 0 . 1 to 5 % of Y 2 O 3 in mole percentage on an oxide basis.
7. The chemically strengthened glass according to claim 1 , which is a glass substrate for a cover glass.
8. The chemically strengthened glass according to claim 1 , wherein A 2 /B 2 [MPa/μm] is 1.8 or less.
9. The chemically stregthened glass according to claim 1 , wherein A 1 /B 1 [MPa/μm]is 180 or more.