Method for improving the edge strength of tempered glass sheet articles
A tempered glass sheet article includes a glass sheet having a thickness t, at least one edge, and at least one surface. The at least one edge is connected to the at least one surface by an edge-to-surface corner. The edge-to-surface corner is rounded with a radius r and has a surface compression that is at least 78% of a surface compression measured at or near a center of the at least one surface.
1. A tempered glass sheet article, comprising:
a glass sheet having a thickness t, at least one edge, and at least one surface, the at least one edge being connected to the at least one surface by an edge-to-surface corner, the edge-to-surface corner being rounded with a radius r and having a surface compression that is at least 78% of a surface compression measured at or near a center of the at least one surface.
2. The tempered glass sheet article of claim 1 , wherein 0.125≦r≦0.5 t.
3. The tempered glass sheet article of claim 1 , wherein the glass sheet is made of glass, glass-ceramic, or glass laminate.
4. The tempered glass sheet article of claim 1 , which is tempered by ion-exchange or chemical tempering.
5. The tempered glass sheet article of claim 1 , wherein the edge-to-surface corner has a compression layer depth that is at least 62% of a compression layer depth measured at or near a center of the at least one surface.
6. The tempered glass sheet article of claim 1 , wherein the at least one edge has inner-edge corners, and the inner-edge corners are rounded.
7. The glass sheet article of claim 1 , wherein the glass sheet is made of an alkali-containing glass.
8. The glass sheet article of claim 7 , wherein the alkali-containing glass comprises: 60-72 mol % SiO 2 ; 9-16 mol % Al 2 O 3 ; 5-12 mol % B 2 O 3 ; 8-16 mol % Na 2 O; and 0-4 mol % K 2 O, wherein the ratio
Al
2
O
3
(
mol
%
)
+
B
2
O
3
(
mol
%
)
∑
alkali
metal
modifiers
(
mol
%
)
>
1
,
where the alkali metal modifiers are alkali metal oxides.
9. The glass sheet article of claim 7 , wherein the alkali-containing glass comprises: 61-75 mol % SiO 2 ; 7-15 mol % Al 2 O 3 ; 0-12 mol % B 2 O 3 ; 9-21 mol % Na 2 O; 0-4 mol % K 2 O; 0-7 mol % MgO; and 0-3 mol % CaO.
10. The glass sheet article of claim 7 , wherein the alkali-containing glass comprises: 60-70 mol % SiO 2 ; 6-14 mol % Al 2 O 3 ; 0-15 mol % B 2 O 3 ; 0-15 mol % Li 2 O; 0-20 mol % Na 2 O; 0-10 mol % K 2 O; 0-8 mol % MgO; 0-10 mol % CaO; 0-5 mol % ZrO 2 ; 0-1 mol % SnO 2 ; 0-1 mol % CeO 2 ; less than 50 ppm As 2 O 3 ; and less than 50 ppm Sb 2 O 3 ; wherein 12 mol %≦Li 2 O+Na 2 O+K 2 O≦20 mol % and 0 mol %≦MgO+CaO≦10 mol %.