Glass member and manufacturing method of glass member
There are provided a manufacturing method of a glass member capable of being cut well without causing a decrease in strength even by using laser light to form a reformed region inside a glass and cutting the glass along the reformed region, and a glass member obtained by the manufacturing method. A glass member 100 having, as a main body thereof, a glass substrate 110 including: strengthened principal surfaces 110 a and an end surface; a reformed region R formed on the end surface made by light radiated to be focused thereto, in which a tension stress (CT) of a center portion in a tension stress region, a fracture toughness (K 1c ) of the glass substrate, and a crack initiation load (CIL) of the glass substrate satisfy a predetermined expression.
1. A glass member comprising:
a glass substrate comprising a strengthened principal surface and an end surface; and
a reformed region formed on the end surface made by radiated light focused on the end surface,
wherein the glass substrate satisfies the following expression (1):
[
a
×
K
1
c
×
{
2
π
(
K
1
c
CT
)
2
×
10
6
}
3
2
]
2
b
+
1
>
3
×
CIL
,
(
1
)
wherein CT is a tension stress of a center portion in a tension stress region formed in a plate thickness direction inside of the glass substrate by the strengthening,
K 1c is a fracture toughness of the glass substrate,
CIL is a crack initiation load of the glass substrate,
wherein K 1c and CIL are a fracture toughness and a crack initiation load of the glass substrate before strengthening,
a is a positive number of from 0.4 to 7, and
b is an integer of from 2 to 7,
wherein a resin layer is formed only on one principal surface of the glass substrate, and the reformed region exists in a closer region to a principal surface side where the resin layer is formed.
2. The glass member according to claim 1 ,
wherein the glass substrate satisfies the following expression (2):
[
a
×
K
1
c
×
{
2
π
(
K
1
c
CT
)
2
×
10
6
}
3
2
]
2
b
+
1
-
[
a
×
K
1
c
×
{
1
π
(
K
1
c
CT
)
2
×
10
6
}
3
2
]
2
b
+
1
>
1.0
,
(
2
)
wherein CT is a tension stress of a center portion in a tension stress region of the glass substrate,
K 1c is a fracture toughness of the glass substrate before strengthening,
a is a positive number of from 0.4 to 7, and
b is an integer of from 2 to 7.
3. The glass member according to claim 1 ,
wherein the glass substrate satisfies the following expression (3) under a condition of k<1,
[
a
×
K
1
c
×
{
1
π
(
K
1
c
CT
)
2
×
10
6
}
3
2
]
2
b
+
1
<
k
{
a
×
K
1
c
×
(
t
2
)
3
2
}
2
b
-
1
,
(
3
)
wherein K 1c is the fracture toughness of the glass substrate before strengthening,
CT is the tension stress of the center portion in the tension stress region of the glass substrate,
a is a positive number of from 0.4 to 7, and
b is an integer of from 2 to 7.
4. The glass member according to claim 1 , wherein, in the tension stress region formed in the plate thickness direction inside of the glass substrate by the strengthening, the tension stress (CT) of the center portion in the tension stress region is 50 MPa to 200 MPa.
5. The glass member according to claim 1 , wherein the glass substrate satisfy the following expression (4):
CS
×
DOL
1000
≤
30
,
(
4
)
wherein CS is a compressive stress of a compressive stress region formed on the surface of the glass substrate, and
DOL is a depth of the compressive stress region.
6. The glass member according to claim 1 , wherein the reformed region is formed in the tension stress region.
7. The glass member according to claim 1 , wherein the crack initiation load (CIL) of the glass substrate before strengthening is less than 2 kgf.
8. The glass member according to claim 1 , wherein a plate thickness (t) of the glass substrate is 0.1 to 0.6 mm.
9. The glass member according to claim 1 , wherein the resin layer contains an infrared absorbing pigment.
10. The glass member according to claim 1 , wherein the resin layer contains a visible light absorbing pigment.
11. The glass member according to claim 1 , wherein the resin layer or the glass substrate has infrared absorptivity.
12. A manufacturing method of a glass member, comprising:
performing strengthening on principal surfaces of a glass plate to satisfy the following expression (1),
[
a
×
K
lc
×
{
2
π
(
K
lc
CT
)
2
×
10
6
}
3
2
]
2
b
+
1
>
3
×
CIL
(
1
)
where CT is a tension stress of a center portion in a tension stress region formed in a plate thickness direction inside of a glass plate by performing strengthening,
K 1c , is a fracture toughness of the glass plate,
CIL is a crack initiation load of the glass plate,
wherein K 1c and CIL are a fracture toughness and crack initiation load of the glass plate before strengthening,
a represents a positive number of 0.4 to 7, and
b represents an integer of 2 to 7;
forming selectively a reformed region by light radiated to be focused inside the glass plate;
cutting the glass plate along the reformed region, and
forming a resin layer only on one principal surface of the glass plate having had the strengthening performed thereon,
wherein the reformed region exists in a closer region to a principal surface side where the resin layer is formed.
13. The manufacturing method of the glass member according to claim 12 , wherein the strengthening is performed to satisfy the following expression (2),
[
a
×
K
lc
×
{
2
π
(
K
lc
CT
)
2
×
10
6
}
3
2
]
2
b
+
1
-
[
a
×
K
lc
×
{
1
π
(
K
lc
CT
)
2
×
10
6
}
3
2
]
2
b
+
1
>
1.0
(
2
)
where CT is the tension stress of the center portion in the tension stress region formed in the plate thickness direction inside of the glass plate,
K 1c is the fracture toughness of the glass plate,
a represents a positive number of 0.4 to 7, and
b represents an integer of 2 to 7.
14. The manufacturing method of the glass member according to claim 12 ,
wherein the strengthening is performed to satisfy following expression (3) under a condition of k<1,
[
a
×
K
1
c
×
{
1
π
(
K
1
c
CT
)
2
×
10
6
}
3
2
]
2
b
+
1
<
k
{
a
×
K
1
c
×
(
t
2
)
3
2
}
2
b
-
1
(
3
)
where K 1 , is the fracture toughness of the glass plate before strengthening,
the CT is tension stress of the center portion in the tension stress region of the glass plate,
a represents a positive number of 0.4 to 7, and
b represents an integer of 2 to 7.
15. The manufacturing method of the glass member according to claim 12 , wherein the tension stress (CT) of the center portion in the tension stress region formed in the plate thickness direction inside of the glass plate by performing strengthening on the principal surfaces of the glass plate is set to 50 MPa to 200 MPa.
16. The manufacturing method of the glass member according to claim 12 , wherein the strengthening is performed so as to satisfy the following expression (4),
CS
×
DOL
1000
≤
30
(
4
)
where CS is a compressive stress of a compressive stress region formed on the surface of the glass plate, and
DOL is a depth of the compressive stress region.
17. The manufacturing method of the glass member according to claim 12 , wherein the reformed region is formed in the tension stress region.
18. The manufacturing method of the glass member according to claim 12 , wherein the crack initiation load (CIL) of the glass plate is less than 2 kgf.
19. The manufacturing method of the glass member according to claim 12 , wherein a plate thickness (t) of the glass plate is 0.1 to 0.6 mm.
20. The manufacturing method of the glass member according to claim 12 , wherein the compressive stress (CS) of the compressive stress region on the surface of the glass plate formed by the strengthening is 200 MPa to 800 MPa.