Sheet of glass with high infrared radiation transmission
The invention relates to a glass sheet with high IR transmission. More precisely, the invention relates to a glass sheet having 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 0-20% CaO 0-15% MgO 0-10% K 2 O 0-10% BaO 0-5% total iron (expressed in the form of Fe 2 O 3 ) 0.002-0.4% and chromium in a content such as: 0.0001%<Cr 2 O 3 <0.002%, expressed in percentages of the total weight of glass. The invention also relates to the use of such a glass sheet in a device using an infrared radiation that propagates essentially inside said sheet. Because of its high IR transmission the glass sheet according to the invention can be advantageously used, for example, in a screen or panel or pad, wherein the glass sheet defines a touch sensitive surface.
1. A glass sheet comprising, in weight percentages in relation to the total weight of the glass sheet:
55-78% of SiO 2 ,
0-18% of Al 2 O 3 ,
0-18% of B 2 O 3 ,
0-20% of Na 2 O,
0-15% of CaO,
0-10% of MgO,
0-10% of K 2 O,
0-5% of BaO,
0.002-0.02% of total iron as expressed in the form of Fe 2 O 3 , and
0.0001%<Cr 2 O 3 <0.002%,
wherein the glass sheet has an absorption coefficient at a wavelength 850 nm of less than or equal to 3.5 m −1 and
wherein the glass sheet comprises Fe 2+ (expressed in the form of FeO) of less than 20 ppm.
2. The glass sheet according to claim 1 , wherein 0.05≦Cr 2 O 3 /Fe 2 O 3 ≦1.
3. The glass sheet according to claim 1 , wherein 0.1≦Cr 2 O 3 /Fe 2 O 3 ≦1.
4. The glass sheet according to claim 1 , comprising 0.0005%≦Cr 2 O 3 <0.002%.
5. The glass sheet according to claim 1 , comprising 0.001%<Cr 2 O 3 <0.002%.
6. The glass sheet according to claim 1 , comprising:
60-75% of SiO 2 ,
0-4% of Al 2 O 3 ,
0-4% of B 2 O 3 ,
5-20% of Na 2 O,
1-15% of CaO,
0-10% of MgO,
0-10% of K 2 O,
0-5% of BaO,
0.002-0.02% of total iron as expressed in the form of Fe 2 O 3 , and
0.0001%<Cr 2 O 3 <0.002%.
7. The glass sheet according to claim 1 , having an absorption coefficient at wavelength 1050 nm of less than or equal to 5 m −1 .
8. The glass sheet according to claim 7 , having an absorption coefficient at wavelength 1050 nm of less than or equal to 3.5 m −1 .
9. The glass sheet according to claim 8 , having an absorption coefficient at wavelength 1050 nm of less than or equal to 2 m −1 .
10. The glass sheet according to claim 1 , being coated with at least one anti-fingerprint layer or treated in order to reduce/prevent fingerprints from showing.
11. A screen, a panel, or a pad comprising at least one glass sheet according to claim 1 , wherein said glass sheet defines a touch sensitive surface.
12. The screen, the panel, or the pad according to claim 11 , having FTIR or PSD optical technology.
13. A glass sheet comprising, in weight percentages in relation to the total weight of the glass sheet:
55-78% of SiO 2 ,
0-18% of Al 2 O 3 ,
0-18% of B 2 O 3 ,
0-20% of Na 2 O,
0-15% of CaO,
0-10% of MgO,
0-10% of K 2 O,
0-5% of BaO,
0.002-0.02% of total iron as expressed in the form of Fe 2 O 3 , and
0.0001%<Cr 2 O 3 <0.002%,
wherein the glass sheet has an absorption coefficient at a wavelength 850 nm of less than or equal to 3.5 m −1 ,
wherein the glass sheet is formed by a float process.
14. The glass sheet according to claim 13 , wherein the glass sheet has a thickness of 0.1 to 2.2 nm.
15. The glass sheet according to claim 13 , wherein 0.05≦Cr 2 O 3 /Fe 2 O 3 ≦1.
16. The glass sheet according to claim 13 , wherein 0.1<Cr 2 O 3 /Fe 2 O 3 <1.
17. The glass sheet according to claim 13 , comprising 0.001%<Cr 2 O 3 <0.002%.