Chemically strengthened glass

Patent metadata

Field	Value
Publication number	US-10457594-B2
Application number	US-201816171556-A
Country	US
Kind code	B2
Filing date	Oct 26, 2018
Priority date	May 15, 2015
Publication date	Oct 29, 2019
Grant date	Oct 29, 2019

Abstract

The present invention relates to a chemically strengthened glass, in which CT1 and CT5 satisfy CT5/CT1≤0.85, the CT1 satisfies CT1>−38.7×ln(t/1000)+48.2 [MPa] and an internal energy density rE satisfies rE≤23.3×t/1000+15 [kJ/m2]. CS is a surface compressive stress value [MPa], σ (x) is a compressive stress value [MPa] at a position x in a depth direction, DOL is a compressive stress depth [μm], and t is a sheet thickness [μm].

First claim

The invention claimed is:

1. A chemically strengthened glass, wherein:
a CT 1 obtained by formula (1) and an internal tensile stress CT 5 obtained by formula (5) satisfy CT 5 /CT 1 ≤0.85;
the internal tensile stress CT 5 is 30 MPa or more;
a compressive stress value at a depth of a half value of a compressive stress depth DOL from a surface of the chemically strengthened glass is 10% or less of a surface compressive stress CS;
a sheet thickness of the chemically strengthened glass is 1000 μm or less; and
when the sheet thickness of the chemically strengthened glass is t (μm),
the CT 1 satisfies CT 1 >−38.7×ln(t/1000)+48.2 [MPa] and
an internal energy density rE obtained by formula (6) satisfies rE≤23.3×t/1000+15 [kJ/m 2 ]:

CT
1

=

CS
×
DOL

(

t
-

2
×
DOL

)

(
1
)

CT
5

=

2
×

∫
0
DOL

⁢

σ
⁡

(
x
)

⁢
dx

(

t
-

2
×
DOL

)

(
5
)

r
⁢

⁢
E

=

CT
5

×

(

t
-

2
×
DOL

)

2

1000
×
t

(
6
)

wherein
CS is a surface compressive stress value [MPa] of the chemically strengthened glass,
σ(x) is a compressive stress value [MPa] at a position x in a depth direction from the surface of the chemically strengthened glass,
DOL is a compressive stress depth [μm] of the chemically strengthened glass, and
t is a sheet thickness [μm] of the chemically strengthened glass.

2. The chemically strengthened glass according to claim 1 , wherein a position having a compressive stress being a half value of the surface compressive stress CS is a position less than 8 μm from the surface of the chemically strengthened glass.

3. The chemically strengthened glass according to claim 2 , wherein the internal tensile stress CT 5 satisfies CT 5 >−38.7×ln(t/1000)+48.2 [MPa].

4. The chemically strengthened glass according to claim 2 , wherein the internal tensile stress CT 5 [MPa] is 1.1 times or more a CT limit value [MPa] obtained by formula (2):
CT limit =−38.7×ln( t/ 1000)+48.2  (2),

wherein t is the sheet thickness [μm] of the chemically strengthened glass.

5. The chemically strengthened glass according to claim 2 , wherein the internal tensile stress CT 5 [MPa] is 1.2 times or more a CT limit value [MPa] obtained by formula (2):
CT limit =38.7×ln( t/ 1000)+48.2  (2),

wherein t is the sheet thickness [μm] of the chemically strengthened glass.

6. The chemically strengthened glass according to claim 2 , wherein the internal tensile stress CT 5 [MPa] is 1.1 times or more a CT limit value [MPa] obtained by formula (4):
CT limit =−36.7×ln( t/ 1000)+48.7  (4),

wherein t is the sheet thickness [μm] of the chemically strengthened glass.

7. The chemically strengthened glass according to claim 2 , wherein the internal tensile stress CT 5 [MPa] is 1.2 times or more a CT limit value [MPa] obtained by formula (4):
CT limit =−36.7×ln( t/ 1000)+48.7  (4),

wherein t is the sheet thickness [μm] of the chemically strengthened glass.

8. A chemically strengthened glass, wherein:
a CT 1 obtained by formula (1) and an internal tensile stress CT 5 obtained by formula (5) satisfy CT 5 /CT 1 ≤0.85;
the internal tensile stress CT 5 is 30 MPa or more;
a compressive stress value at a depth of a half value of a compressive stress depth DOL from a surface of the chemically strengthened glass is 10% or less of a surface compressive stress CS;
a sheet thickness of the chemically strengthened glass is 1000 μm or less; and
when the sheet thickness of the chemically strengthened glass is t (μm),
the CT 1 satisfies CT 1 >−38.7×ln(t/1000)+48.2 [MPa] and
an internal energy density rE obtained by formula (6) satisfies rE≤23.3×t/1000+15 [kJ/m 2 ]:

CT
1

=

CS
×
DOL

Assignees

• Agc Inc

Inventors

• AKATSUKA Kosho
• Ogami Satoshi

Classifications

• C03C21/002 Primary

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

• C03C4/00 Primary

  Compositions for glass with special properties · CPC title

• C03C3/085

  containing an oxide of a divalent metal · CPC title

• C03C2201/00

  Glass compositions · CPC title

• C03C2204/00

  Glasses, glazes or enamels with special properties · CPC title