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RF induction lamp with reduced electromagnetic interference

  • US 8,698,413 B1
  • Filed: 11/26/2012
  • Issued: 04/15/2014
  • Est. Priority Date: 11/26/2012
  • Status: Active Grant
First Claim
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1. An induction radio frequency (RF) fluorescent lamp, comprising:

  • a lamp envelope with a re-entrant cavity both covered on a partial vacuum side with phosphor and filled with a working gas mixture;

    a tubular ferromagnetic core on a non-vacuum side of said re-entrant cavity, wherein one or more radial spacers support the tubular ferromagnetic core to be axial to the re-entrant cavity with a fixed air gap between them;

    two windings on said tubular ferromagnetic core having a different number of turns, a first winding being an active winding having one end connected to an RF ballast and the other end connected to local ground and a second winding being a passive winding having one end grounded and the other end free.

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