Ceravision Limited

Edwin Charles Odell

Barry Preston

Andrew Simon Neate

Donald M Wilson

Floyd Pothoven

Amjid Sadiq

Charles Guthrie

Robin Devonshire

Hussein Sonde

Martyn Roscoe

The manufacture of an electrodeless bulb involves one end of a tube closed off, and a first neck is formed in the tube close to the closed end. A second neck is formed in the tube, close to the still open end; a metal halide pellet of known size is dropped into the tube and the tube is evacuated. With the vacuum being maintained heat is applied to the closed end, causing the metal halide pellet to sublime and with it the impurities. The impurities are drawn off, the vacuum being maintained and the metal halide condenses in the tube between the necks. Once the tube is cool, the evacuation is discontinued and the tube is refilled with noble gas and the quartz tube is sealed off at the second neck.

Method of manufacturing an electrode-less incandescent bulb

A plasma crucible has a through bore and two tubes butt scaled on to the end faces of the crucible. One of the tubes is closed prior to the filling of the crucible. The tube is tipped off and worked in a glass lathe to form it to have a flat end. After evacuation, dosing and gas fill, the other tube is tipped off in the similar manner.

Plasma crucible sealing

An electrodeless bulb has a hollow quartz tube, with a solid stem extending from one end and a short hollow tip extending from the other end. The hollow interior of the tube extends into the tip with the same diameter as in the tube, but the wall thickness of the tip is reduced from that of the tube. The bulb is charged with an amount of indium bromide and traces of other metal halides to adjust light spectrum and a filling of xenon gas.

Electrodeless bulb having improved dimensions for light emission

Growing community of inventors

Leicester, United Kingdom

Edwin Charles Odell