Mounting construction for ignition antenna in High pressure discharge lamps
Publication Date: 2005-Nov-22
The IP.com Prior Art Database
Nowadays, the best-known UHP burner is equipped with an UV-Enhancer cavity is one seal surrounded by a metal antenna. In applications, like project television, the specification will be a Hot Restrike time of 30-45 sec maximum. During experiments with a 5-6 kVolt resonant voltage waveform we observed, at Hot-Restrike time less than 40 seconds, discharge formation around the metal parts of the burner, that is: around the metal wire of the antenna and around the outer lead wire.
The application of a resonant waveform results in a discharge of the UV-Enhancer, the emitting UV-photons hits both the antenna wires and the outer lead wire.
See the next picture as a visualisation aid.
So on the metal wires free electrons are liberated. At the same time the air surrounding the metal parts are at a elevated temperature ( at least 350 degrees Celsius). So corona discharges are initiated at the metal parts., this will result in a
destructive arc discharge between the antenna wire and the outer lead wire. A possible end-of-live of the burner is the result.
The proposed measure:
Let the last piece of the antenna wire end in a dialectical chamber, which is sealed on the end seal of the UHP burner (preferentially a quartzcylinder sealed on the already cylinder shaped seal of the UHP burner.
Advantage 1: Now so-called micro-discharges are formed between the metal outer lead wire and the dielectric wall of the antenna wire containment. Thes...