Thorn Emi Plc

General Electric Company

Thorn Electrical Industries Limited

Basil Antonis

John M Chapman

Steven John Everest

An electrodeless fluorescent lamp comprises a sealed lamp vessel containing a fill capable of sustaining a discharge when suitably excited. The fill is excited by an RF electromagnetic field produced by a winding energized by an RF oscillator powered via a rectifier from the mains. To confine the RF field within the vessel a conductive coating FTO is provided inside the vessel. To at least reduce conducted interference a conductive coating A1 is provided on the outside of the vessel G. The coating A1 is electrically coupled (e.g., via 7) to RF ground which may be one side of the mains. An electrically insulative housing covers the coating A1. The housing which extends to a zone of maximum diameter of the vessel may grip the vessel.

Electrodeless fluorescent lamp having an insulative housing arrangement

The invention provides an advantageous shape of discharge tube and a discharge lamp including such a tube which is particularly beneficial for use in dimensions intended to replace general lighting service lamps but can readily be adapted to other sizes. The discharge tube is shaped to define a substantial part of the boundary of a substantially planar zone. The part of the tube defining the boundary includes at least one straight portion. In one embodiment it defines three sides of a square with the ends of the tube being re-entrant into the fourth side. In a preferred embodiment a support housing central to the zone holds the ends of the tube thereby supporting it. Preferably one or more arms extending from the support housing grip the tube between its ends for further support. The support housing may include some circuit elements and provides electrical connection to the lamp as well as providing a convenient point to handle the lamp.

Discharge lamps

Discharge lamps with curved sections and central connections

Fluorescent lamp

In a method of dosing a gas discharge lamp by opening a dosing capsule by the heating action of an electromagnetic field on a metallic support, the support is in the form of a sheet metal clip embracing the capsule and having an opening through which the softened glass of the capsule is forced by the internal pressure. Breakage of the capsule is eliminated and the glass forced through the opening ensures retention of the capsule by the clip. The clip is preferably of ferromagnetic material.

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London, United Kingdom

Basil Antonis