Electrodeless inductively-coupled fluorescent lamp with improved cavity and tubulation
US5723947A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 20, 1996 |
| Grant date | Mar 3, 1998 |
| Priority date | — |
| Expiry date | Dec 20, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J61/52
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An electrodeless inductively-coupled fluorescent lamp which operates at ro frequency comprising a bulbous envelope (1) filled with rare gas and metal vapor. A reentrant cavity (4) and an induction coil (6) are disposed in the cavity (4). The inner walls of the envelope (1) and the cavity (4) have a protective coating (3) and a phosphor coating (2). A metal Faraday cylinder (12) welded to the lamp base (13) is disposed between the cavity (4) and the coil (6) to reduce capacitive RF voltage between the coil and the plasma to improve lamp maintenance and remove heat. A tubulation (16) is disposed on the lamp axis to evacuate the envelope (1). The proximal end of the tubulation (16) has an expansion (20) with the volume (23) where the initial capacitive discharge is ignited. The RF coil voltage needed for the ignition of the capacitive discharge in the expansion area (23) is substantially lower than that needed for the ignition of the capacitive discharge in the area (14) along the inner cavity walls (4) to decrease the lamp starting voltage. In one of the embodiments of the present invention the expansion is conically shaped and in another it is cylindrically shaped and is used to gen…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.