Aluminum-free borosilicate glass and applications thereof
AssigneeSchott AG
InventorChristof Kass
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Abstract
The fluorescent lamp is made with an aluminum-free borosilicate glass having a composition, in percent by weight, based on oxide content of: SiO2, 65-77; B2O3, 7-20; Li2O, 0-2; Na2O, 0-4; K2O, 3-12; MgO, 0-2; CaO, 0-2; with MgO+CaO, 0-3; BaO, 0-3; ZnO, 0-2; ZrO2, 0.8-12; TiO2, 0-10; CeO2, 0-1; and F−, 0-0.6. Preferred embodiments with more than 1% by weight TiO2 have especially good UV blocking properties and are especially suitable for lamp glass for backlights. Other embodiments have good sealing properties to tungsten, KOVAR®, and molybdenum and have coefficients of thermal expansion α of 4.7 to 5.3×10−6/K, good chemical resistance, and a working point VA of between 990° C. and 1290° C.
Claims7
A fluorescent lamp comprising a lamp glass, said lamp glass consisting of an aluminum-free borosilicate glass, said aluminum-free borosilicate glass having chemical resistance and a composition, in percent by weight, based on oxide content, of:
- SiO2
- 60-78
- B2O3
- 7-20
- Li2O
- 0-2
- Na2O
- 0-4
- K2O
- 3-12
- MgO
- 0-2
- CaO
- 0-2
- with MgO + CaO
- 0-3
- BaO
- 0-3
- ZnO
- 0-2
- ZrO2
- 0.8-12
- TiO2
- 0-10
- CeO2
- 0-1
- F−
- 0-0.6
- and optionally at least one refining agent in a standard amount for refining.
Dependencies are inferred from the claim text.