High frequency ferrite-free electrodeless flourescent lamp with axially uniform plasma

摘要

An electrodeless fluorescent lamp employs a glass envelope made from a single linear tube filled with inert gas and mercury vapor. Phosphor and protective coatings are disposed on the inner surface of the envelope walls. An induction coil of few turns made from silver coated copper or Litz wire is wrapped around the linear tube in its axial direction. The inductively-coupled axially uniform plasma is generated inside the linear tube. The discharge electric field and current form a closed-loop path inside a tube in its axial direction. The lamp is operated at frequencies from 100 KHz to 100 MHz and RF power from 10 W to 2000 W (dependent on lamp size and number of turns). The lamp power efficiency and efficacy are comparable to those in electrodeless lamps of closed-loop shape operated with and without ferrite core.