Glass sheet having a high transmission in the infrared
View Patent ↗The invention relates to a glass sheet having a high transmission in the infrared, especially usable in a touch screen, touch panel or touch pad. More precisely, the invention relates to a glass sheet having a composition that comprises, in an amount expressed in percentages by total weight of glass: SiO 2 55-85%, Al 2 O 3 0-30%, B 2 O 3 0-20%, Na 2 O 0-25%, CaO 0-20%, MgO 0-15%, K 2 O 0-20%, BaO 0-20%, Total iron (expressed in Fe 2 O 3 form) 0.002-0.06%; and cerum in an amount (expressed in CeO 2 form) ranging from 0.001 to 1%. The invention also relates to the use of such a glass sheet in a device using infrared radiation propagating essentially inside said sheet. By virtue of its high transmission of infrared radiation, the glass sheet according to the invention may advantageously be used, for example, in a screen or panel or tablet, the glass sheet defining a touch surface.
1. A touch screen or touch panel or touch pad comprising:
a glass sheet, the glass sheet comprising
in an amount expressed in percentages by a total weight of the glass sheet:
SiO 2
55-85%;
Al 2 O 3
0-30%;
B 2 O 3
0-20%;
Na 2 O
0-25%;
CaO
0-20%;
MgO
0-15%;
K 2 O
0-20%;
BaO
0-20%;
total iron as expressed in Fe 2 O 3 form 0.002-0.06%; and
cerium as expressed in CeO 2 form 0.001-1%,
wherein the touch screen or touch panel or touch pad uses FTIR or PSD optical technology.
2. The touch screen or touch panel or touch pad according to claim 1 , the glass sheet comprising:
cerium as expressed in CeO 2 form in an amount of from 0.005 to 0.5% by weight relative to the total weight of the glass.
3. The touch screen or touch panel or touch pad according to claim 1 , the glass sheet comprising:
cerium as expressed in CeO 2 form in an amount of from 0.005 to 0.3% by weight relative to the total weight of the glass.
4. The touch screen or touch panel or touch pad according to claim 3 , the glass sheet comprising:
cerium as expressed in CeO 2 form in an amount of from 0.01 to 0.2% by weight relative to the total weight of the glass.
5. The touch screen or touch panel or touch pad according to claim 1 , the glass sheet comprising:
total iron as expressed in Fe 2 O 3 form in an amount of from 0.002 to 0.04% by weight relative to the total weight of the glass.
6. The touch screen or touch panel or touch pad according to claim 5 , the glass sheet comprising:
total iron as expressed in Fe 2 O 3 form in an amount of from 0.002 to 0.02% by weight relative to the total weight of the glass.
7. The touch screen or touch panel or touch pad according to claim 1 , the glass sheet comprising:
Fe 2+ as expressed in FeO form in an amount of lower than 10 ppm.
8. The touch screen or touch panel or touch pad according to claim 7 , the glass sheet comprising:
Fe 2+ as expressed in FeO form in an amount of lower than 5 ppm.
9. The touch screen or touch panel or touch pad according to claim 1 , wherein the glass sheet has an absorption coefficient at a wavelength of 1050 nm of lower than 5 m −1 .
10. The touch screen or touch panel or touch pad according to claim 1 , the glass sheet comprising in an amount expressed in percentages by the total weight of the glass sheet:
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%;
and
BaO
0-5%.
11. A device, comprising a touch screen or touch panel or touch pad, the device further comprising:
a glass sheet that comprises, in an amount expressed in percentages by total weight of the glass sheet:
SiO 2
55-85%;
Al 2 O 3
0-30%;
B 2 O 3
0-20%;
Na 2 O
0-25%;
CaO
0-20%;
MgO
0-15%;
K 2 O
0-20%;
BaO
0-20%;
total iron as expressed in Fe 2 O 3 form 0.002-0.06%; and
cerium as expressed in CeO 2 form 0.001-1%,
wherein infrared radiation propagates essentially inside said sheet.
12. The device according to claim 11 , wherein the infrared radiation propagates by total internal reflection.
13. The device according to claim 11 , wherein the glass sheet comprises the total iron content as expressed in Fe 2 O 3 form of from 0.002 to 0.04% by weight relative to the total weight of the glass.
14. A touch screen or touch panel or touch pad comprising:
a glass sheet, the glass sheet comprising:
in an amount expressed in percentages by a total weight of the glass sheet:
SiO 2
55-85%;
Al 2 O 3
0-30%;
B 2 O 3
0-20%;
Na 2 O
0-25%;
CaO
0-20%;
MgO
0-15%;
K 2 O
0-20%;
BaO
0-20%;
total iron as expressed in Fe 2 O 3 form 0.002-0.02%; and
cerium as expressed in CeO 2 form 0.001-0.3%,
wherein Fe 2+ as expressed in FeO form is present in the glass sheet in an amount lower than 10 ppm, and
wherein the touch screen or touch panel or touch pad uses FTIR or PSD optical technology.
15. The touch screen or touch panel or touch pad according to claim 14 , the glass sheet comprising:
Fe 2+ as expressed in FeO form in an amount of lower than 5 ppm.
16. The touch screen or touch panel or touch pad according to claim 14 , wherein the glass sheet has an absorption coefficient at a wavelength of 1050 nm of lower than 5 m −1 .
17. The touch screen or touch panel or touch pad according to claim 14 , wherein the glass sheet has an absorption coefficient at a wavelength of 1050 nm of lower than 2 m −1 .
18. The touch screen or touch panel or touch pad according to claim 14 , the glass sheet comprising:
cerium as expressed in CeO 2 form in an amount of from 0.01 to 0.2% by weight relative to the total weight of the glass.
19. The touch screen or touch panel or touch pad according to claim 14 , the glass sheet comprising:
a cerium/total iron ratio satisfying the equation 1≤CeO 2 /Fe 2 O 3 ≤50.
20. The touch screen or touch panel or touch pad according to claim 14 , the glass sheet comprising:
a cerium/total iron ratio satisfying the equation 1≤CeO 2 /Fe 2 O 3 ≤10.