Gas discharge lamp assembly with improved r.f. shielding
First Claim
1. An inductively driven gas discharge lamp assembly, comprising:
- an electrodeless gas discharge lamp having a sealed envelope containing an ionizable gas fill, said envelope having at least one light transmissive end portion;
an inductive drive coil disposed about said envelope, said drive coil having a central, longitudinal axis that extends through said lamp envelope, whereby an alternating current driven through said drive coil produces a time-varying magnetic field that impinges upon said gas fill;
characterized in that;
the lamp assembly further comprises a shield disposed over said end portion of said lamp envelope, said shield having a number of turns of electrically conductive material with each of said turns being disposed generally coaxially about said longitudinal axis in spaced relation from the others of said turns, wherein at least some of said turns are shorted together by a number of electrical conductors that are angularly disposed about said axis and that extend generally perpendicularly to said turns.
5 Assignments
0 Petitions
Accused Products
Abstract
An inductively driven gas discharge lamp assembly (40) includes an electrodeless lamp (42), an inductive drive coil (44) disposed about the lamp, and a shield (10) disposed over an end portion (50) of the lamp. The shield (10) has a number of turns (12) of electrically conductive material, such as wire, with each of the turns being disposed generally coaxially about the central, longitudinal axis (20) of the drive coil (44). The turns (12) together form a continuous spiral helix and are shorted together via a number of electrical conductors (14) that are angularly disposed about the axis (20). These electrical conductors (14) extend generally perpendicularly to the turns (12) and are connected to the ground node (26) of a d.c. to a.c. inverter circuit 46 that is used to drive coil 44. This arrangement provides good r.f. electric field and magnetic field shielding and permits the use of relatively few turns (12) at a relatively large spacing of the turns so as to minimize the interference of the shield (10) on the amount of light emitted from the lamp (42). Also disclosed is another embodiment (30) in which the turns (32) each comprise a single loop rather than a continuous spiral helix.
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Citations
14 Claims
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1. An inductively driven gas discharge lamp assembly, comprising:
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an electrodeless gas discharge lamp having a sealed envelope containing an ionizable gas fill, said envelope having at least one light transmissive end portion;
an inductive drive coil disposed about said envelope, said drive coil having a central, longitudinal axis that extends through said lamp envelope, whereby an alternating current driven through said drive coil produces a time-varying magnetic field that impinges upon said gas fill;
characterized in that;
the lamp assembly further comprises a shield disposed over said end portion of said lamp envelope, said shield having a number of turns of electrically conductive material with each of said turns being disposed generally coaxially about said longitudinal axis in spaced relation from the others of said turns, wherein at least some of said turns are shorted together by a number of electrical conductors that are angularly disposed about said axis and that extend generally perpendicularly to said turns. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification