General Electric Company

David O Wharmby

Louis Robert Nerone

Thomas Frederick Soules

Joseph Darryl Michael

Sayed-Amr A El-Hamamsy

George A Farrall

Zoltan Toth

Frederick Hetzel

Vito J Arsena

Joseph C Oberle

Timothy A Taubert

Gordon Alexander Grigor

Robert S McFeely

Thomas Farkas

Istvan Nagy

Mahomed Hanif Girach

Gerald W Ludwig

Steven John Everest

Mohamed Hanif Girach

A coil assembly for an electrodeless fluorescent lamp comprises a hollow ferrite core 30, and a coil 31. The core is retained on a base 32 by a coil former 34 surrounding the core. The core 30 is retained in the former 34 by a circlip 33 or projections. The coil 31 is wound on the former. Pins 36 to which the coil is soldered connect the coil to an energizing circuit.

Coil assembly for an electrodeless fluorescent lamp

An electrodeless fluorescent lamp having an envelope with an improved shape. The invented shape is shorter and the light-trapping area near the neck is substantially reduced or eliminated. The ratio of the operational width to the operational height of the envelope is preferably at least 1.5 and the reflector face angle is preferably less than 40.degree..

Electrodeless fluorescent lamp

An electrodeless gas discharge lamp includes a vitreous envelope containing a discharge medium. An excitation coil is positioned in relation to the vitreous envelope so as to excite the discharge medium therein. The excitation coil is adapted to be driven by an RF oscillator. The excitation coil has first and second ends and is effective for exciting the discharge medium to emit light with electromagnetic fields that are generated by the excitation coil. The excitation coil includes a first wire wound generally helically from the first end to the second end in a first helical direction to form first winding turns, and further includes a second wire wound generally helically from the first end to the second end in second helical direction opposite to that of the first helical direction to form second winding turns. Preferably, a generally cylindrical former is provided for holding the first and second wires between the first and second ends of the coil. Such former includes a positioning arrangement for maintaining specific positions of the first and second wires with respect to each other along the former.

Induction lamp with oppositely oriented coil winding layers

An electrodeless fluorescent lamp having a lamp envelope with an inner phosphor coating and containing a fill capable of sustaining a discharge when suitably excited by an electric field includes an electrically conductive coating on the exterior of the lamp envelope. The electrically conductive coating is also light transmissive and is effective for confining the electric field to within the lamp envelope.

Electrodeless fluorescent lamp with an electrically conductive coating

An electrodeless fluorescent lamp comprises a discharge vessel (10) having a re-entrant portion (11) for housing a solenoid (12) for initiating a discharge in the vessel by means of an RF electromagnetic field. A primary amalgam (18) for releasing mercury vapor is placed at the tip of an exhaust tube (17) where the primary amalgam can be maintained at a suitable temperature for controlling the mercury vapor pressure. The primary amalgam does not provide rapid run-up of light output. To provide rapid run-up of light output a pied of indium (20,30) is placed on the re-entrant at a position where it is rapidly heated by the discharge. The indium may be coated with the layers of a coating including phosphor.

Electrodeless fluorescent lamp having a reduced run-up time

An impedance matching circuit for a self-oscillating electrodeless fluorescent lamp ballast of the type having an inductor connected in series with the parallel combination of a capacitor and the lamp's drive coil includes an additional capacitor connected in series with the drive coil. The capacitance value chosen for the additional capacitor is dependent on: stresses on the parallel capacitor; matching the impedance of the ballast; and the impact of the capacitor on the loaded coil phase angle. The additional capacitor reduces the phase angle presented to the ballast, thereby lowering the sensitivity of the ballast to component and lamp variations. In addition, the overall impedance of the network is reduced, such that the required inductance of the series inductor is reduced; hence, the inductor can have fewer turns and lower conduction losses. The current in inductor for the required power level is lower, resulting in a further reduction in conduction losses as well as a reduction in core losses due to lower flux in the core. Still further, a reduction of stresses on the inductor results in a reduced operating temperature, and hence increased efficiency, reliability and ballast life.

Impedance matching circuit for an electrodeless fluorescent lamp ballast

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Ilkley, United Kingdom

David O Wharmby