US Patent 7906910 Plasma lamp with conductive material positioned relative to RF feed

In an example embodiment, an electrodeless plasma lamp is provided which comprises a lamp body comprising a dielectric material having a relative permittivity greater than 2, and a bulb adjacent to the lamp body, the bulb containing a fill that forms a plasma when RF power is coupled to the fill from the lamp body. An RF feed is coupled to the lamp body and a radio frequency (RF) power source for coupling power into the lamp body through the RF feed is provided. A shortest distance between an end of the bulb and a point on the RF feed traverses at least one electrically conductive material of the lamp body.