Microwave-powered light source

• Main Author: NEATE, ANDREW SIMON
• Format: Patent
• Language: English; French; German
• Published: 23.02.2011
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS; ELECTRICITY

A lamp comprises a light source in the form of a light emitting resonator 1, a magnetron 2 and a stub tuner 3. A reflector 4 is fitted at the junction of the light source and the stub tuner, for directing the light in a generally collimated beam 5. The light emitting resonator comprises an enclosure 11 formed of inner and outer envelopes 12,13 of quartz. These are circular cylindrical tubes 14,15, with respective end plates 16,17. A tungsten wire mesh 18, of a mesh size to exhibit a ground plane to microwaves within the resonator, is sandwiched between the tubes and the end plates respectively. Each envelope, comprised of its tube and end plates is hermetic. An earth connection 18' extends from the mesh to the outside of the envelope. The length axially of the enclosure between the wire mesh sandwiched between the end plates is »/2 for the operating microwave frequency. At one end of the enclosure, a molybdenum drive connection 19 extends to a tungsten disc 20. This is arranged transverse the axis A of the enclosure at 1/16 » from the mesh at its end of the enclosure. The enclosure is filled with excitable plasma material, such as a dose of metal halide in a rare earth gas. The disc acts as antenna and is driven by the magnetron 2, via the matching circuit 3.