Electrodeless low-pressure discharge lamp
AssigneeU.S. Philips Corporation
InventorsPieter Postma, Andreas C. van Veghel
Life of this patent
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Abstract
An electrodeless low-pressure discharge lamp comprising a glass lamp vessel sealed in a gas-tight manner and filled with a metal vapor and a rare gas, and a winding on a ferrite core. During lamp operation an electrical discharge is maintained in the lamp vessel by the winding connected to a high-frequency supply. The winding is surrounded by a thin-walled cylindrical metal body or layer which is electrically insulated from the winding, is interrupted at at least one area and is connected during operation of the lamp to one of the power mains conductors.
Claims23
An electrodeless low-pressure discharge lamp comprising a glass lamp vessel which is sealed in a gas-tight manner and is filled with a metal vapor and a rare gas, this lamp being provided with a core of magnetic material, while during operation of the lamp an electric discharge is maintained in the lamp vessel by means of a wire winding connected to a high-frequency supply unit and arranged to surround the core, characterized in that the winding is surrounded in its immediate proximity by an thin-walled cylindrical metal body which is electrically insulated therefrom, is interrupted throughout its length at at least one area and is connected during operation of the lamp to one of the lead-in wires of the supply mains.
In an electrodeless fluorescent lamp having a sealed discharge vessel with a portion protruding inwardly of the vessel, a magnetic core disposed exterior to said discharge vessel within said protruding portion of said vessel, and a conductive winding wound around said magnetic core and energizable by a high-frequency signal for developing a field and maintaining a discharge within said vessel during lamp operation, the improvement comprising:
- a discontinuous conductive layer disposed opposite said winding and insulated from said winding, said discontinuous layer having an interruption extending in the length dimension of said winding along the entire length of said layer, and means for electrically connecting said conductive layer to power mains during lamp operation.
Dependencies are inferred from the claim text.