Cover assembly for electronic display devices
A cover assembly for a display device, such as a three-dimensional liquid crystal (3-D LCD) display. The cover assembly includes an aluminosilicate glass substrate that is substantially free of retardance-induced visual defects and has a thickness of less than 2 mm, a retardance of less than or equal to 5 nm over an area of at least 170 in 2 (20 in diagonal), a 4-point bend strength of greater than 150 MPa.
1. A cover assembly for a display device, the cover assembly comprising an aluminosilicate glass substrate having a thickness of less than 2 mm, an area of at least 170 in 2 (20 in diagonal), a retardance of less than or equal to 5 nm over the area of at least 170 in 2 (20 in diagonal), a 4-point bend strength of greater than 150 MPa, and at least one of an antiglare surface and an anti-reflectance surface, and wherein the aluminosilicate glass substrate is substantially free of retardance induced visual defects.
2. The cover assembly of claim 1 , wherein the retardance, when present in the cover glass assembly, comprises a thermally induced retardance component.
3. The cover assembly of claim 1 , wherein at least one of the antiglare surface and the anti-reflectance surface is a coating disposed over a surface of the aluminosilicate glass substrate.
4. The cover assembly of claim 1 , wherein the thickness of the aluminosilicate glass substrate varies by less than 1 μm/cm.
5. The cover assembly of claim 1 , wherein the aluminosilicate glass substrate comprises a cord having an average cord height of less than 20 nm over a period ranging from 2 mm to 10 mm.
6. The cover assembly of claim 1 , wherein the aluminosilicate glass substrate has a liquidus viscosity of greater than 130,000 poise at temperatures below 1275° C.
7. The cover assembly of claim 1 , wherein the display device is a 3-D LCD device.
8. The cover assembly of claim 1 , wherein the aluminosilicate glass is down-drawn.
9. The cover assembly of claim 1 , wherein the aluminosilicate glass substrate is an alkali-free aluminosilicate glass.
10. The cover assembly of claim 9 , wherein the alkali-free aluminosilicate glass comprises: 64.0-71.0 mol % SiO 2 ; 9.0-12.0 Al 2 O 3 ; 7.0-12.0 mol % B 2 O 3 : 1.0-3.0 mol % MgO; 6.0-11.5 mol % CaO; 0-1.0 mol % SrO; and 0-0.1 mol % BaO, wherein Σ[RO]/[Al 2 O 3 ]≧1.00.
11. The cover assembly of claim 1 , wherein the aluminosilicate glass substrate is an alkali aluminosilicate glass.
12. The cover assembly of claim 11 , wherein the alkali aluminosilicate glass comprises, in mole percent as oxides on a batched basis, of 40-80% SiO 2 , 0-28% Al 2 O 3 , 0-8% B 2 O 3 , 0-18% Li 2 O, 0-10% Na 2 O, 0-11% K 2 O, 0-16% MgO, 0-18% CaO, 0-15% CaF 2 , 0-20% SrO, 0-12% BaO, 0-8% ZnO, 0-4% P 2 O 5 , 0-8% TiO 2 , 0-5% ZrO 2 , 0-1% SnO 2 and 0-1Sb 2 O 3 , 0-1% As 2 O 3 .
13. The cover assembly of claim 11 , wherein the alkali aluminosilicate glass comprises: 64 mol %≦SiO 2 ≦68 mol %; 12 mol %≦Na 2 O≦16 mol %; 8 mol %≦Al 2 O 3 ≦12 mol %; 0 mol %≦B 2 O 3 ≦3 mol %; 2 mol %≦K 2 O≦5 mol %; 4 mol %≦MgO≦6 mol %; and 0 mol %≦CaO≦5 mol %, wherein: 66 mol %≦SiO 2 +B 2 O 3 +CaO≦69 mol %; Na 2 O+K 2 O+B 2 O 3 +MgO+CaO+SrO>10 mol %; 5 mol %≦MgO+CaO+SrO≦8 mol %; (Na 2 O+B 2 O 3 )−Al 2 O 3 ≦2 mol %; 2 mol %≦Na 2 O−Al 2 O 3 ≦6 mol %; and 4 mol %≦(Na 2 O+K 2 O)−Al 2 O 3 ≦10 mol %.
14. The cover assembly of claim 11 , wherein the alkali aluminosilicate 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 %.
15. The cover assembly of claim 11 , wherein the alkali aluminosilicate glass comprises: 61 mol %≦SiO 2 ≦75 mol %; 7 mol %≦Al 2 O 3 ≦15 mol %; 0 mol %≦B 2 O 3 ≦12 mol %; 9 mol %≦Na 2 O≦21 mol %; 0 mol %≦K 2 O≦4 mol %; 0 mol %≦MgO≦7 mol %; and 0 mol %≦CaO≦3 mol %.
16. The cover assembly of claim 11 , wherein the alkali aluminosilicate silicate 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, and wherein the ratio
Al
2
O
3
(
mol
%
)
+
B
2
O
3
(
mol
%
)
Σ
modifiers
(
mol
%
)
>
1
,
where Na 2 O and K 2 O are modifiers.
17. The cover assembly of claim 11 , wherein the alkali aluminosilicate glass is ion-exchanged.
18. The cover assembly of claim 17 , wherein the ion-exchanged alkali aluminosilicate glass has a compressive surface layer having a depth of layer greater than or equal to 2% of the thickness of the aluminosilicate glass substrate.
19. The cover assembly of claim 17 , wherein the ion-exchanged alkali aluminosilicate glass is free of damage from chipping, the damage having a size greater than three times a width w of a scratch formed by a Knoop diamond at a load of at least 5 N.
20. The cover assembly of claim 17 , wherein the alkali aluminosilicate glass exhibits a 4-point bend strength of greater than 350 MPa.