Highly thermally loaded electric lamp with reduced UV light emission, and method of its manufacture
US5336969A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 9, 1992 |
| Grant date | Aug 9, 1994 |
| Priority date | — |
| Expiry date | Jun 9, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J61/40
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
To reduce the transmissivity of glass, and particularly quartz glass, espally highly thermally loaded quartz glass of discharge lamps or halogen incandescent lamps, a coating or glaze is applied to the bulb and adjacent regions which includes, as an ultraviolet light absorption, a glaze of a mixture of cerium fluoride (CeF.sub.3) and aluminum trioxide (Al.sub.2 O.sub.3) and silicon dioxide (SiO.sub.2), in a relationship, by weight, of about 3:1, preferably about 2:1. The weight relationship of Al.sub.2 O.sub.3 to SiO.sub.2 in the mixture is about 1.7:1. The mixture can be applied in form of an alcohol or alcohol-like suspension, after grinding to a grain size of less than 300 mesh, by spraying, dripping on, painting or the like, subsequent drying for 10 seconds, and firing in a hydrogen/oxygen flame or in an ordinary gas flame for about 2 seconds, while axially rotating the lamp bulb.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.