UV-radiation absorbing glass with high chemical resistance, especially for a fluorescent lamp, and methods of making and using same
View Patent ↗The chemically resistant borosilicate glass has the following composition (in % by weight): SiO 2 , 67-74; B 2 O 3 , 5-10; Al 2 O 3 , 3-10; Li 2 O, 0-4; Na 2 O, 0-10; K 2 O, 0-10; MgO, 0-2; CaO, 0-3; SrO, 0-3; BaO, 0-3; ZnO, 0-3; ZrO 2 , 0-3; CeO 2 , 0-1; with ΣLi 2 O+Na 2 O+K 2 O=0.5 to 10.5 and ΣMgO+CaO+SrO+BaO+ZnO=0-6. The borosilicate glass is characterized by a composition including 0 to 10% of at least one of TiO 2 , Bi 2 O 3 and MoO 3 and a sum total of TiO 2 +Bi 2 O 3 +MoO 3 of 0.1 to 10%. This glass is obtained from the melt under oxidative conditions. The glass is useful in gas discharge lamps, such as Xenon lamps and fluorescent lamps, and display devices, flat structured backlighting devices, and glass-to-metal seals with Mo, Wo and Ni—Fe—Co alloys.
1. A chemically resistant borosilicate glass with a composition comprising:
SiO 2
67-74%
by weight
B 2 O 3
5-10%
by weight
Al 2 O 3
5-10%
by weight
Li 2 O
0-4%
by weight
Na 2 O
0-10%
by weight
K 2 O
0-10%
by weight,
wherein Σ Li 2 O + Na 2 O + K 2 O
0.5-10.5%
by weight,
MgO
0-2%
by weight
CaO
0-3%
by weight
SrO
0-3%
by weight
BaO
0-3%
by weight
ZnO
0-3%
by weight,
wherein Σ MgO + CaO + SrO + BaO + ZnO
0-6%
by weight,
ZrO 2
0-3%
by weight
CeO 2
0-1%
by weight
TiO 2
0-10%
by weight
Bi 2 O 3
0-10%
by weight
MoO 3
0-10%
by weight,
wherein Σ TiO 2 + Bi 2 O 3 + MoO 3
0.1-10%
by weight; and
wherein at least 80% by weight of titanium present in the glass has an oxidation state of +4 when said titanium is contained in the glass.
2. The chemically resistant borosilicate glass as defined in claim 1 , wherein said composition includes at least 50 ppm Fe 2 O 3 .
3. The chemically resistant borosilicate glass as defined in claim 1 , free of chloride and antimony monoxide.
4. The chemically resistant borosilicate glass as defined in claim 1 , wherein
SiO 2
67-<73%
by weight
B 2 O 3
7-10%
by weight
Al 2 O 3
5.5-9%
by weight
Li 2 O
0.5-2%
by weight
wherein Σ MgO + CaO + SrO + BaO + ZnO
0-3%
by weight,
ZrO 2
0.8-3%
by weight;
and containing at least 0.06 percent by weight of said TiO 2 in order to adjust a position and sharpness of a UV absorption edge of the glass; and wherein at least 80 % by weight of titanium present in the glass has an oxidation state of +4.
5. The chemically resistant borosilicate glass as defined in claim 1 , wherein:
SiO 2
68-69%
by weight
B 2 O 3
9.5-9.95%
by weight
Al 2 O 3
5.5-6.5%
by weight
Li 2 O
1.5-2.5%
by weight
Na 2 O
0-4.0%
by weight
K 2 O
0.5-7%
by weight
MgO
0.5-2%
by weight
CaO
0.5-1.5%
by weight
ZrO 2
0.8-1.2%
by weight
TiO 2
2-10%
by weight; and
wherein at least 80% by weight of titanium present in the glass has an oxidation state of +4.
6. The chemically resistant borosilicate glass as defined in claim 1 , wherein at least 90% by weight of said titanium present therein is in said oxidation state of +4.
7. A glass-to-metal seal comprising a molybdenum and/or cobalt-iron-nickel alloy and a chemically resistance borosilicate glass as defined in claim 1 .
8. A light conducting plate comprising a glass as defined in claim 1 and consisting of a support plate or a structured plate for monitors, displays and/or gas discharge lamps with external electrodes.
9. A process for making a gas discharge lamp, a fluorescence lamp, a Xenon lamp, an LCD display, a computer monitor, a telephone display and/or an edge seal with a molybdenum or an iron-cobalt-nickel alloy, said process comprising forming a borosilicate glass according to claim 1 to make said gas discharge lamp, said fluorescence lamp, said Xenon lamp, said LCD display, said computer monitor, said telephone display and/or said edge seal with said molybdenum or said iron-cobalt-nickel alloy.
10. A process of using a borosilicate glass comprising forming a borosilicate glass according to claim 1 as a light conducting plate, a support plate or a structure plate for a monitor, display and/or a gas discharge lamp with external electrodes.
11. A method of making a neutral UV-absorbing borosilicate glass, which transmits in a visible range, said method comprising melting raw materials to form a melt and producing said melt under oxidative conditions,
wherein said borosilicate glass has the following composition:
SiO 2
67-74%
by weight
B 2 O 3
5-10%
by weight
Al 2 O 3
5-10%
by weight
Li 2 O
0-4%
by weight
Na 2 O
0-10%
by weight
K 2 O
0-10%
by weight,
wherein Σ Li 2 O + Na 2 O + K 2 O
0.5-10.5%
by weight,
MgO
0-2%
by weight
CaO
0-3%
by weight
SrO
0-3%
by weight
BaO
0-3%
by weight
ZnO
0-3%
by weight,
wherein Σ MgO + CaO + SrO + BaO + ZnO
0-6%
by weight,
ZrO 2
0-3%
by weight
CeO 2
0-1%
by weight
TiO 2
0-10%
by weight
Bi 2 O 3
0-10%
by weight
MoO 3
0-10%
by weight,
wherein Σ TiO 2 + Bi 2 O 3 + MoO 3
0.1-10%
by weight; and
wherein at least 80 % by weight of titanium present in the glass has an oxidation state of +4 when said titanium is contained in the glass.
12. The method as defined in claim 11 , wherein said borosilicate glass contains at least 50 ppm Fe 2 O 3 .
13. The method as defined in claim 11 , wherein said SiO 2 and/or said raw material contains greater than 100 ppm Fe 2 O 3 .
14. The method as defined in claim 11 , wherein said oxidative conditions are produced by addition of alkali nitrates and/or alkaline earth nitrates.
15. The method as defined in claim 11 , wherein said melt contains up to a maximum of 6 percent by weight of alkali nitrates and/or alkaline earth nitrates in order to produce said oxidative conditions.
16. The method as defined in claim 11 , wherein said melt contains up to a maximum of 100 ppm chloride.
17. A gas discharge lamp comprising chemically resistant borosilicate glass, said chemically resistant borosilicate glass having a composition comprising:
SiO 2
67-74%
by weight
B 2 O 3
5-10%
by weight
Al 2 O 3
3-10%
by weight
Li 2 O
0-4%
by weight
Na 2 O
0-10%
by weight
K 2 O
0-10%
by weight,
wherein Σ Li 2 O + Na 2 O + K 2 O
0.5-10.5%
by weight,
MgO
0-2%
by weight
CaO
0-3%
by weight
SrO
0-3%
by weight
BaO
0-3%
by weight
ZnO
0-3%
by weight,
wherein Σ MgO + CaO + SrO + BaO + ZnO
0-6%
by weight,
ZrO 2
0-3%
by weight
CeO 2
0-1%
by weight
TiO 2
0-10%
by weight
Bi 2 O 3
0-10%
by weight
MoO 3
0-10%
by weight,
Wherein Σ TiO 2 + Bi 2 O 3 + MoO 3
0.1-10%
by weight; and
wherein at least 80% by weight of titanium present in the glass has an oxidation state of +4 when said titanium is contained in the glass.
18. The gas discharge lamp as defined in claim 17 , consisting of a fluorescence lamp or a Xenon lamp.
19. A display device comprising chemically resistant borosilicate glass, said chemically resistant borosilicate glass having a composition comprising:
SiO 2
67-74%
by weight
B 2 O 3
5-10%
by weight
Al 2 O 3
3-10%
by weight
Li 2 O
0-4%
by weight
Na 2 O
0-10%
by weight
K 2 O
0-10%
by weight,
wherein Σ Li 2 O + Na 2 O + K 2 O
0.5-10.5%
by weight,
MgO
0-2%
by weight
CaO
0-3%
by weight
SrO
0-3%
by weight
BaO
0-3%
by weight
ZnO
0-3%
by weight,
wherein Σ MgO + CaO + SrO + BaO + ZnO
0-6%
by weight,
ZrO 2
0-3%
by weight
CeO 2
0-1%
by weight
TiO 2
0-10%
by weight
Bi 2 O 3
0-10%
by weight
MoO 3
0-10%
by weight,
wherein Σ TiO 2 + Bi 2 O 3 + MoO 3
0.1-10%
by weight; and
wherein at least 80% by weight of titanium present in the glass has an oxidation state of +4 when said titanium is contained in the glass.
20. The display device as defined in claim 19 , consisting of a computer monitor, a telephone display or a liquid crystal display.
21. The chemically resistant borosilicate glass as defined in claim 1 , wherein said composition includes from 0.01 to 2% by weight of As 2 O 3 .