Glass for chemical strengthening, chemically strengthened glass, and electronic device case

Patent metadata

Field	Value
Publication number	US-11718556-B2
Application number	US-202016747584-A
Country	US
Kind code	B2
Filing date	Jan 21, 2020
Priority date	Jul 26, 2017
Publication date	Aug 8, 2023
Grant date	Aug 8, 2023

Abstract

The present invention pertains to a glass for strengthening, that: has an average transmittance of at least 70% when converted to a thickness of 0.8 mm at a wavelength of 380-780 nm; has a haze value of no more than 0.7% when converted to a thickness of 0.8 mm in a C light source; has a Young's modulus of at least 85 GPa; has a fracture toughness value of at least 0.90 MPa·m1/2; a thermal conductivity at 20° C. of at least 1.3 W/m·K; and comprises a lithium aluminosilicate crystallized glass.

First claim

The invention claimed is:

1. A glass for chemical strengthening, comprising a lithium aluminosilicate crystallized glass, and comprising, as expressed by mass % on an oxide basis:
58 to 71% of SiO 2 ;
8 to 30% of Al 2 O 3 ;
1 to 15% of Li 2 O;
1 to 5% of Na 2 O;
0 to 2% of K 2 O;
0 to 6% of SnO 2 ;
0 to 8% of ZrO 2 ;
0 to 6% of P 2 O 5 ;
0 to 1% of BaO; and
0 to 2% of ZnO,
a total of SnO 2 and ZrO 2 being 4 to 12%,
wherein the glass for chemical strengthening is free of As 2 O 3 and Sb 2 O 3 , and
the glass for chemical strengthening has:
an average transmittance at a wavelength of 380 to 780 nm of 70% or higher in terms of a thickness of 0.8 mm;
a haze value of 0.7% or lower in terms of the thickness of 0.8 mm at a C illuminant;
a Young's modulus of 85 GPa or more;
a fracture toughness value of 0.90 MPa·m 1/2 or more; and
a thermal conductivity at 20° C. of 1.3 W/m·K or more.

2. The glass for chemical strengthening according to claim 1 , having a Vickers hardness of 680 or more.

3. The glass for chemical strengthening according to claim 1 , wherein the crystallized glass comprises a β-spodumene.

4. The glass for chemical strengthening according to claim 1 , comprising, as expressed by mass % on an oxide basis:
60 to 70% of SiO 2 ,
12 to 25% of Al 2 O 3 ;
1.5 to 10% of Li 2 O;
1 to 4% of Na 2 O;
0 to 5% of SnO 2 ,
0 to 6% of ZrO 2 ; and
0 to 5% of P 2 O 5 .

5. The glass for chemical strengthening according to claim 1 , which is free of BaO.

6. The glass for chemical strengthening according to claim 1 , which is free of K 2 O.

7. The glass for chemical strengthening according to claim 1 , which is free of TiO 2 .

8. The glass for chemical strengthening according to claim 1 , having the haze value of 0.4% or lower.

9. The glass for chemical strengthening according to claim 1 , wherein a content ratio Li 2 O/Al 2 O 3 between Li 2 O and Al 2 O 3 is 0.3 or less.

10. The glass for chemical strengthening according to claim 1 , wherein a ratio SnO 2 /(SnO 2 +ZrO 2 ) of the SnO 2 content to the total of SnO 2 and ZrO 2 is 0.3 to 0.7.

11. A chemically strengthened glass, comprising a lithium aluminosilicate crystallized glass, and comprising, as expressed by mass % on an oxide basis:
58 to 71% of SiO 2 ;
8 to 30% of Al 2 O 3 ;
1 to 15% of Li 2 O;
1 to 5% of Na 2 O;
0 to 2% of K 2 O;
0 to 6% of SnO 2 ;
0 to 8% of ZrO 2 ;
0 to 6% of P 2 O 5 ;
0 to 1% of BaO; and
0 to 2% of ZnO,
a total of SnO 2 and ZrO 2 being 4 to 12%,
wherein the glass for chemical strengthening is free of As 2 O 3 and Sb 2 O 3 , and
the glass for chemical strengthening has:
an average transmittance at a wavelength of 380 to 780 nm of 70% or higher in terms of a thickness of 0.8 mm;
a haze value of 0.7% or lower in terms of the thickness of 0.8 mm at a C illuminant;
a Young's modulus of 85 GPa or more;
a fracture toughness value of 0.90 MPa·m 1/2 or more;
a thermal conductivity at 20° C. of 1.3 W/m·K or more; and
a surface compressive stress of 500 MPa or more, and a depth of a compressive stress layer of 45 μm or more.

12. The chemically strengthened glass according to claim 11 , having a Vickers hardness of 700 or more.

13. The chemically strengthened glass according to claim 11 , wherein the crystallized glass comprises a β-spodumene.

14. The chemically strengthened glass according to claim 11 , comprising, as expressed by mass % on an oxide basis:
60 to 70% of SiO 2 ,
12 to 25% of Al 2 O 3 ;
1.5 to 10% of Li 2 O;
1 to 4% of Na 2 O;
0 to 5% of SnO 2 ;
0 to 6% of ZrO 2 ; and
0 to 5% of P 2 O 5 .

15. The chemically strengthened glass according to claim 11 , wherein the depth of a compressive stress layer is 60 μm or more, and a maximum depth where a compressive stress value is 50 MPa or more is 50 μm or more.

16. An electronic device housing member comprising the chemically strengthened glass according to claim 11 .

17. An electronic device housing, wherein a surface area of a part formed of the chemically strengthened glass according to claim 11 occupies 40% or higher with respect to a surface area of the housing.

18. The electronic device housing according to claim 17 , wherein a thickness of a thinnest part of the chemically strengthened glass is 0.6 mm or less.

Assignees

• Agc Inc

Inventors

• Li Qing
• Koike Akio
• Maeda Eriko

Classifications

• C03C21/002 Primary

  to perform ion-exchange between alkali ions (C03C21/005 takes precedence) · CPC title

• C03C3/083

  containing aluminium oxide or an iron compound · CPC title

• C03C4/0028

  for crystal glass, e.g. lead-free crystal glass · CPC title

• C03C10/0027

  containing SiO2, Al2O3, Li2O as main constituents · CPC title

• C03C3/097 Primary

  containing phosphorus, niobium or tantalum · CPC title