Claims
- 1. A material that undergoes a decrease in light transmission when exposed to UV-radiation in either the glass or glass-ceramic state, that is thermally bleachable after darkening, and that consists essentially of an alumino-silicate based glass containing CdF2.
- 2. A material in accordance with claim 1 in which the composition consists essentially of, as calculated from the batch, 20-40 mole % SiO2, 10-20 mole % AlO1.5, 33-55 mole % SiO2+AlO1.5, at least 30 mole % CdF2, 0-20 mole % of zinc and/or lead fluoride and 0-15 mole % of a rare earth metal fluoride, the total metal fluoride being 45-65 mole %.
- 3. A material in accordance with claim 2, in which the composition additionally contains up to 15 mole % PbF2.
- 4. A material in accordance with claim 2 wherein the composition additionally contains up to 15 mole % zinc fluoride.
- 5. A material in accordance with claim 2 wherein the composition contains at least 2 mole % of at least one rare earth metal fluoride selected from the group consisting of gadolinium, yttrium, ytterbium and lutetium fluorides.
- 6. A material in accordance with claim 2 wherein the CdF2 is at least about 35 mole % in the absence of zinc and/or lead fluoride.
- 7. A material in accordance with claim 1, optionally containing Pb and/or Zn and/or rare earth metal fluorides in its composition.
- 8. A material according to claim 1, wherein said CdF2 is present in an amount of at least 30 mole %.
- 9. A material according to claim 1, wherein said material has increased conductivity in the reduced light transmission state.
- 10. A glass or glass-ceramic article which exhibits UV-induced, light transmission and electrical conductivity behavior, the article having a composition consisting essentially of silica, alumina, and cadmium fluoride.
- 11. An article in accordance with claim 10, the article having a composition including at least 2 mole % of at least one fluoride selected from the group consisting of gadolinium, ytterbium, yttrium and lutetium fluorides.
- 12. An article in accordance with claim 10 wherein the composition contains up to 20 mole % of PbF2 and/or ZnF2.
- 13. An article in accordance with claim 10 in which the composition consists essentially of, as calculated from the batch, 20-40 mole % SiO2, 10-20 mole % AlO1.5, 33-55 mole % SiO2+AlO1.5, at least 30 mole % CdF2, 0-20 mole % of zinc and/or lead fluoride and 0-15 mole % of a rare earth metal fluoride, the total metal fluoride being 45-65 mole %.
- 14. An article in accordance with claim 13 wherein the CdF2 is at least about 35 mole % in the absence of zinc and/or lead fluoride.
- 15. An article in accordance with claim 10, the article having a composition that additionally contains up to 15 mole % PbF2.
Parent Case Info
The present application is a continuation of U.S. patent application Ser. No. 09/167,754, filed Oct. 7, 1998, now abandoned, which claims the benefit of U.S. Provisional Patent Application Serial No. 60/062,243, filed Oct. 17, 1997.
US Referenced Citations (3)
Number |
Name |
Date |
Kind |
5483628 |
Borrelli et al. |
Jan 1996 |
A |
5537505 |
Borrelli et al. |
Jul 1996 |
A |
5973865 |
Havens et al. |
Oct 1999 |
A |
Non-Patent Literature Citations (3)
Entry |
U.S. patent application Ser. No. 09/130,800, Bartholomew et al., filed Aug. 7, 1998. |
U.S. patent applicaiton Ser. No. 09/081,856, Bange et al., filed May 19, 1998. |
Miura et al., “Optical Properties in Cadmium Borosilicate Glasses,” Collected Papers, XIV Intl. Congr. on Glass, pp. 139-146 (1986). |
Provisional Applications (1)
|
Number |
Date |
Country |
|
60/062243 |
Oct 1997 |
US |
Continuations (1)
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Number |
Date |
Country |
Parent |
09/167754 |
Oct 1998 |
US |
Child |
09/793368 |
|
US |