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×[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, comprising:
50 to 67% of SiO 2 , 7 to 30% of Al 2 O 3 , 2 to 10% of B 2 O 3 , 0 to 3% of P 2 O 5 , 2 to 8% of MgO, 0 to 3% of CaO, 0 to 2% of SrO, 0 to 2% of BaO, 0 to 2% of ZnO, 0 to 2% of TiO 2 , 0 to 2% of ZrO 2 , 7.5 to 15% of Li 2 O, 1 to 6% of Na 2 O, and 0 to 3% of K 2 O in mole percentage on an oxide basis,
wherein the chemically strengthened glass satisfies A 1 [MPa] of 600 or more, A 2 [MPa] of 150 or more, B 1 [μm] of 6.0 or less, B 2 [μm] of 10% or more of t [μm], B 2 [μm] of 125 μm or more, C [MPa] of −50 or less, 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 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, erfc is a complementary error function, and relations of A 1 >A 2 and B 1 <B 2 are satisfied, and the thickness t is 0.3 mm or more and 2 mm or less.
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 B 2 [μm] is 40% or more of t [μm].
4. The chemically strengthened glass according to claim 1 , wherein A 2 [MPa] is 200 or more.
5. The chemically strengthened glass according to claim 1 , wherein A 2 [MPa] is 300 or more.
6. The chemically strengthened glass according to claim 1 , wherein C [MPa] is −70 or less.
7. The chemically strengthened glass according to claim 1 , wherein B 1 [μm] is 5.0 or less.
8. The chemically strengthened glass according to claim 1 , wherein B 1 [μm] is 3.5 or less.
9. The chemically strengthened glass according to claim 1 , wherein A 1 [MPa] is 700 or more.
10. The chemically strengthened glass according to claim 1 , wherein A 1 [MPa] is 800 or more.
11. The chemically strengthened glass according to claim 1 , wherein the number of fragments generated within a size of 25 mm×25 mm is 100 or less in a fracture test according to an indenter indentation test under a condition of holding a load ranging from 5 kgf to 10 kgf for 15 seconds with a pyramidal diamond indenter having an indenter angle of the facing angle of 90°.
12. The chemically strengthened glass according to claim 1 , wherein, in a test of colliding a diamond indenter on the glass surface by using a pendulum impact tester, a kinetic energy of the diamond indenter when a fragmentation probability of the glass is 50% is 80 mJ or more.
13. The chemically strengthened glass according to claim 1 , wherein the chemically strengthened glass comprises 56 to 67% of the SiO 2 , 7 to 30% of the Al 2 O 3 , 2 to 10% of the B 2 O 3 , 0 to 1% of the P 2 O 5 , 3 to 8% of the MgO, 0 to 1% of the CaO, 0 to 1% of the SrO, 0 to 1% of the BaO, 0 to 1% of the ZnO, 0 to 0.25% of the TiO 2 , 0 to 2% of the ZrO 2 , 7.5 to 12% of the Li 2 O, 1 to 6% of the Na 2 O, and 0 to 2% of the K 2 O in mole percentage on an oxide basis.
14. The chemically strengthened glass according to claim 1 , which is a glass substrate for a cover glass.
15. The chemically strengthened glass according to claim 1 , wherein A 2 /B 2 [MPa/μm] is 2.5 or less.
16. The chemically strengthened glass according to claim 1 , wherein A 1 /B 1 [MPa/μm] is 150 or more.
17. The chemically strengthened glass according to claim 1 , wherein A 1 /B 1 [MPa/μm] is 180 or more.
18. The chemically strengthened glass according to claim 1 , wherein A 1 /B 1 [MPa/μm] is 220 or more.
19. The chemically strengthened glass according to claim 1 , wherein B 1 [μm] is 2.3 or less.
20. The chemically strengthened glass according to claim 1 , wherein A 1 /B 1 [MPa/μm] is 293 or more.