(19)
(11) EP 0 087 962 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
09.05.1984 Bulletin 1984/19

(43) Date of publication A2:
07.09.1983 Bulletin 1983/36

(21) Application number: 83301034

(22) Date of filing: 25.02.1983
(84) Designated Contracting States:
DE FR GB NL

(30) Priority: 26.02.1982 US 352676

(71) Applicant: GTE Laboratories Incorporated
 ()

(72) Inventors:
  • Byszewski, Wojciech W.
     ()
  • Proud, Joseph M.
     ()
  • Budinger, Bowman A.
     ()

   


(54) Beam mode fluorescent lamp having dual cathodes with unipotential ends


(57) A beam mode lamp has two thermionic electrodes (33, 34) which when energized by AC power function alternately as cathode and anode. Electrodes emitted from a cathode are shaped by the anode into electron beams (e) which excite a gaseous mixture into radiating ultraviolet light and secondary electrons. A phosphor coating (37) on the envelope (31) of the lamp connects the ultraviolet radiation into visible light. During start the electrodes (33, 34) are connected in series. During operation the electrodes (33, 34) are disconnected from each other. The ends of each electrode are then connected making the two ends of an electrode at substantially the same electrical potential. This arrangement results in improved luminous output efficacy and longer operating life of the lamp.






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