Planar electrodeless fluorescent light source

摘要

A light source includes a planar electrodeless fluorescent lamp. The lamp envelope has two parallel light transmitting plates separated and sealed by a spacing frame, has a phosphor coating on its inner surface, and encloses a fill material which emits ultraviolet radiation upon excitation by high frequency power. The phosphor coating emits visible light upon absorption on ultraviolet radiation. An induction coil for excitation of the lamp by high frequency power includes conductive loops located on the surface of the lamp with the plane of each loop parallel to the plane of the lamp. The induction coil is configured so that current flow in adjacent loops is in opposite directions in order to minimize the far field radiation level.