STRENGTHENED GLASS PLATE
A strengthened glass plate includes: a first functional layer that is provided in a first main surface of the strengthened glass plate; and a second functional layer that is provided in a second main surface of the strengthened glass plate. When a stress in a tensile stress layer is designated as CT, the following relation regarding the CT is satisfied: CT>0.8×[−38.7×ln(t/1000)+48.2], where t is a plate thickness [μm], CS is a compressive stress [MPa] in an outermost surface, and DOL is a depth [μm] from a glass surface to a point where the compressive stress reaches zero in a thickness direction.
1 . A strengthened glass plate comprising:
a first functional layer that is provided in a first main surface of the strengthened glass plate; and
a second functional layer that is provided in a second main surface of the strengthened glass plate, wherein:
when a stress in a tensile stress layer is designated as CT, the CT being obtained by the following formula (1),
CT
=
CS
×
DOL
t
-
2
×
DOL
(
1
)
the following relation regarding the CT is satisfied:
CT> 0.84×[−38.7×ln( t/ 1000)+48.2]
wherein t is a plate thickness [μm], CS is a compressive stress [MPa] in an outermost surface, and DOL is a depth [μm] from a glass surface to a point where the compressive stress reaches zero in a thickness direction.
2 . The strengthened glass plate according to claim 1 , wherein:
the following relation regarding the stress CT in the tensile stress layer is satisfied:
CT> 0.9×[−38.7×ln( t/ 1000)+48.2].
3 . The strengthened glass plate according to claim 2 , wherein:
the following relation regarding the stress CT in the tensile stress layer is satisfied:
CT> 0.954×[−38.7×ln( t/ 1000)+48.2].
4 . A strengthened glass plate comprising:
a first functional layer that is provided in a first main surface of the strengthened glass plate; and
a second functional layer that is provided in a second main surface of the strengthened glass plate, wherein:
when the following relation is satisfied based on characteristic values of a strengthened layer that has been chemically strengthened:
[
CS
×
DOL
t
-
2
×
DOL
]
/
[
2
×
∫
0
DOL
CS
(
x
)
dx
t
-
2
×
DOL
]
≥
85
%
the following relation regarding a specific energy density rE is satisfied:
rE> 0.8×[23.3× t/ 1000+15]
wherein the rE is obtained by the following formula (2):
rE
=
CT
×
(
t
-
2
×
DOL
)
2
1000
×
t
(
2
)
and t is a plate thickness [μm], CS is a compressive stress [MPa] in an outermost surface, CS(x) is a compressive stress [MPa] in depth x [μm], and DOL is a depth [μm] from a glass surface to a point where the CS(x) reaches zero in a thickness direction.
5 . The strengthened glass plate according to claim 4 , wherein:
the following relation regarding the specific energy density rE is satisfied:
rE> 0.9×[23.3× t/ 1000+15].
6 . The strengthened glass plate according to claim 5 , wherein:
the following relation regarding the specific energy density rE is satisfied:
rE> 0.95×[23.3× t/ 1000+15].
7 . The strengthened glass plate according to claim 1 , wherein:
at least one of the first function layer and the second functional layer is a layer that provides optical disturbance.
8 . The strengthened glass plate according to claim 4 , wherein:
at least one of the first function layer and the second functional layer is a layer that provides optical disturbance.
9 . The strengthened glass plate according to claim 7 , wherein:
the layer that provides optical disturbance is a roughened layer, and the roughened layer has an arithmetic average roughness Ra of 0.1 μm or more.
10 . The strengthened glass plate according to claim 8 , wherein:
the layer that provides optical disturbance is a roughened layer, and the roughened layer has an arithmetic average roughness Ra of 0.1 μm or more.
11 . The strengthened glass plate according to claim 7 , wherein:
the layer that provides optical disturbance is a layer that has been doped with at least one element selected from the group consisting of Sn, Ag, Ti, Ni, Co, Cu and In.
12 . The strengthened glass plate according to claim 8 , wherein:
the layer that provides optical disturbance is a layer that has been doped with at least one element selected from the group consisting of Sn, Ag, Ti, Ni, Co, Cu and In.