Patent Number: 6,297,583

Title: Gas discharge lamp assembly with improved r.f. shielding

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.

Inventors: Kohne; Robert L. (Noblesville, IN), Bodem, Jr.; Jack D. (Kokomo, IN)

Assignee: Federal-Mogul World Wide, Inc.

International Classification: H01J 61/04 (20060101); H01J 65/04 (20060101); H01J 61/02 (20060101); H01J 61/56 (20060101); H01J 5/02 (20060101); H01J 001/50 (); H01J 023/10 (); H01J 029/76 ()

Expiration Date: 10/02/2018