X-ray Opaque Barium-Free Glasses and Uses Thereof
AssigneeSchott AG
InventorsSimone Monika Ritter, Oliver Hochrein, Sabine Pichler-Wilhelm
Life of this patent
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Abstract
Zirconium-containing BaO- and PbO-free X-ray opaque glasses having a refractive index nd of about 1.54 to about 1.58 and a high X-ray opacity with an aluminum equivalent thickness of at least about 500% are provided. Such glasses are based on a SiO2—B2O3—Al2O3—R2O—RO—La2O3—ZrO2 system with optional additions of SnO2. Such glasses may be used, in particular, as dental glasses or as optical glasses.
Claims23
A BaO- and/or PbO-free X-ray opaque glass having a refractive index nd of about 54 to about 1.58 and an aluminum equivalent thickness of at least about 500%, comprising (in % by weight based on oxide)
- SiO2
- 48-56
- B2O3
- 3-8
- Al2O3
- 0.5-4
- Li2O
- 0-5
- Na2O
- 1-4
- K2O
- 2-7
- Cs2O
- 10-16
- CaO
- 5-9
- MgO
- 0-5
- ZrO2
- 0.5-13
- La2O3
- 5-12
- SnO2
- 0-4
- Σ alkali metal oxides
- 16-21
- CsO2 + La2O3 + SnO2
- ≧19.
Dependencies are inferred from the claim text.