LOW SPARKLE GLASS SHEET
The invention relates to a glass sheet comprising at least one etched surface having a surface roughness defined, when measured on an evaluation length of 12 mm and with a Gaussian filter of which the cut-off wavelength is 0.8 mm, by: 0.02≦Ra≦0.4 microns, 5≦RSm≦30 microns, said glass sheet having the following optical properties, when measured from said etched surface: a haze value of from 1 to 40%; a clarity value of from 50 to 100%; a gloss value at 60° of from 20 to 110 SGU. Such a glass sheet which is particularly suitable for display applications as cover glass. In particular, the glass sheet of the invention has excellent anti-sparkling properties together with an anti-glare effect. Moreover, the glass sheet of the invention also combines anti-glare and anti-sparkling properties with a “soft touch”.
1 . A glass sheet comprising at least one etched surface having a surface roughness defined, when measured on an evaluation length of 12 mm and with a Gaussian filter of which the cut-off wavelength is 0.8 mm, by:
0.02≦Ra≦0.4 microns,
5≦RSm≦30 microns,
said glass sheet having the following optical properties, when measured from said etched surface:
a haze value of from 1 to 40%;
a clarity value of from 50 to 100%;
a gloss value at 60° of from 20 to 110 SGU.
2 . The glass sheet according to claim 1 , wherein the surface roughness of the at least one etched surface has a Rz value greater than 0.05 and less than 2.5 microns.
3 . The glass sheet according to claim 1 , wherein the at least one etched surface has a surface roughness of 10≦RSm≦30 microns.
4 . The glass sheet according to claim 1 , wherein the at least one etched surface has a surface roughness of 10≦RSm≦25 microns.
5 . The glass sheet according to claim 1 , wherein the at least one etched surface has a surface roughness of 10≦RSm≦20 microns.
6 . The glass sheet according to claim 1 , wherein the at least one etched surface has a surface roughness of 0.02≦Ra≦0.2 microns.
7 . The glass sheet according to claim 1 , wherein the at least one etched surface has a surface roughness of 0.02≦Ra≦0.15 microns.
8 . The glass sheet according to claim 1 , wherein the at least one etched surface has a surface roughness of 0.1≦Rz≦2.0 microns.
9 . The glass sheet according to claim 1 , wherein the glass sheet has a clarity of from 85 to 100%.
10 . The glass sheet according to claim 1 , wherein a haze is from 1 to 20%.
11 . The glass sheet according to claim 1 , wherein the surface roughness of the etched surface is defined by:
0.02≦Ra≦0.4 microns,
5≦RSm≦15 microns,
and said glass sheet has the following optical properties, when measured from said etched surface:
haze value of from 30 to 40%;
clarity value of from 50 to 100%;
gloss value at 60° of from 20 to 50 SGU.
12 . The glass sheet according to claim 1 , wherein anti-sparkling measured as detailed in the specification using a SMS 1000 of Display-Messtechnik & Systeme company is at least 0.8 and preferably 0.85.
13 . The glass sheet according to claim 12 , wherein the anti-sparkling measured is at least 0.9 and preferably at least 0.95.
14 . The glass sheet according to claim 1 , wherein the glass sheet has a composition comprising, in a content expressed in percentages of the total weight of the glass:
SiO 2
55-78%
Al 2 O 3
0-18%
B 2 O 3
0-18%
Na 2 O
5-20%
CaO
0-15%
MgO
0-10%
K 2 O
0-10%
BaO
0-5%.
15 . The glass sheet according to claim 14 , wherein the glass sheet has a composition comprising, in a content expressed in percentages of the total weight of the glass:
SiO2
65-78%
Al2O3
0-6%
B2O3
0-4%
CaO
0-15%
MgO
0-10%
Na2O
5-20%
K2O
0-10%
BaO
0-5%.
16 . The glass sheet according to claim 14 , wherein the glass sheet has a composition comprising, in a content expressed in percentages of the total weight of the glass:
SiO 2
55-70%
Al 2 O 3
6-18%
B 2 O 3
0-4%
CaO
0-15%
MgO
0-10%
Na 2 O
5-20%
K 2 O
0-10%
BaO
0-5%.
17 . The glass sheet according to claim 1 , wherein the glass sheet is chemically tempered.
18 . A display device comprising a glass sheet according to claim 1 .