Neodymium glass for tungsten-halogen lamp envelopes and filters
US6358873B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Jun 15, 2000 |
| Grant date | Mar 19, 2002 |
| Priority date | — |
| Expiry date | Jun 27, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01K1/28
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A glass for tungsten halogen lamp glass envelopes, glass filter lenses, and glass filters consisting essentially in terms of weight percent on the oxide basis, of about 50-62% SiO2, 10-17% Al2O3, 0-6% B2O3, 3.6-10% CaO, 0-7.5% MgO, 0.1-0.3% SrO, 2.4-18% BaO, 0-1% ZnO, 1-8% Nd2O3. The glass exhibits the following physical properties: strain point between about 665° C. to about 750° C., coefficient of thermal expansion to the set point of between about 49-59×10−7/° C., liquidus temperature below 1320° C., viscosity at liquidus temperature greater than 2,000 poises, and transmission at 585 nm of between 5-60% for a 1.2 mm thickness. The lamp color temperature for a tungsten halogen lamp containing a glass envelope, a glass filter lens, or a glass filter prepared from the glass composition is increased from about 3 to 7% above a similar glass with no Nd2O3, and the total visible lumen loss is limited to less than about 10%.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.