Capacitive starting electrodes for hid lamps
AssigneeGeneral Electric Company
InventorHarald L. Witting
Life of this patent
Estimating the term…
Abstract
A pair of starting electrodes are provided for an electrodeless high-intensity-discharge lamp arc of the type having an envelope situated within the bore of an excitation coil and in the interior of which envelope is to be provided a plasma arc discharge driven by the excitation coil. Each of the starting electrodes is a conductive ring disposed adjacent to an associated one of an opposed pair of envelope surfaces, and connected to an opposite end of the excitation coil. A high-voltage signal coupled between the starting electrodes causes an electric field to be produced sufficient to create a glow discharge in the arc tube, and cause an almost instantaneous transition to a high-current solenoidal discharge to form the discharge plasma responsive to the normal field provided by the excitation coil.
Claims13
Starting electrodes for an electrodeless high-intensity-discharge (HID) lamp of the type having an arc tube situated within the bore of an RF excitation coil and within which arc tube a plasma arc discharge is to be formed and driven by the excitation coil, comprising:
- a pair of starting electrodes, each positioned, at least during commencement of the plasma arc discharge, adjacent to the exterior surface of an associated one of a pair of opposed surfaces of the arc tube, said starting electrodes not substantially driving said plasma arc discharge, and at least one of the starting electrodes having a cross-sectional shape selected to be a conical section substantially similar to the shape of the exterior arc tube surface adjacent to which that electrode will be located at least during plasma arc discharge commencement;
- and
- means for coupling a high-voltage starting signal between the pair of starting electrodes to cause creation, at least at said plasma arc discharge commencement, of a glow discharge within the arc tube due to capacitive current flow therethrough from said starting electrodes.
Starting electrodes for an electrodeless high-intensity-discharge (HID) lamp of the type having an arc tube situated within the bore of an RF excitation coil and within which arc tube a plasma arc discharge is to be formed and driven by the excitation coil, comprising:
- a pair of starting electrodes, at least one of said electrodes being a substantially ring-shaped conductive member with each ring-shaped electrode having a gap portion therein devoid of conductive material, each starting electrode positioned, at least during commencement of the plasma arc discharge, adjacent to the exterior surface of an associated one of a pair of opposed surfaces of the arc tube, said starting electrodes not substantially driving said plasma arc discharge;
- and
- means for coupling a high-voltage starting signal between the pair of starting electrodes to cause creation, at least at said plasma arc discharge commencement, of a glow discharge within the arc tube due to capacitive current flow therethrough from said starting electrodes.
Starting electrodes for an electrodeless high-intensity-discharge (HID) lamp of the type having an arc tube situated within the bore of an RF excitation coil and within which arc tube a plasma arc discharge is to be formed and driven by the excitation coil, comprising:
- a pair of starting electrodes, each positioned, at least during commencement of the plasma arc discharge, adjacent to the exterior surface of an associated one of a pair of opposed surfaces of the arc tube, said starting electrodes not substantially driving said plasma arc discharge;
- and
- means for coupling a high-voltage starting signal between the pair of starting electrodes to cause creation, at least at said plasma arc discharge commencement, of a glow discharge within the arc tube due to capacitive current flow therethrough from said starting electrodes and, responsive to establishment of said discharge, for moving the starting electrodes to a location further from said arc tube than the location of the electrodes during discharge commencement.
Dependencies are inferred from the claim text.