(19)
(11) EP 0 668 605 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
26.03.1997 Bulletin 1997/13

(43) Date of publication A2:
23.08.1995 Bulletin 1995/34

(21) Application number: 95100561.0

(22) Date of filing: 17.01.1995
(51) International Patent Classification (IPC)6: H01J 65/04, H01J 61/30
(84) Designated Contracting States:
DE FR GB IT

(30) Priority: 17.02.1994 HU 9400450

(71) Applicant: TUNGSRAM Részvénytársaság
H-1340 Budapest IV (HU)

(72) Inventors:
  • Balázs, Lászlo
    Budapest, XIII. (HU)
  • Downton, Kenneth James
    Leicester, LE2 0JF (GB)
  • Everest, Steven John
    Leicester, LE2 1FQ (GB)
  • Sajo, Gábor
    Budapest, IV (HU)
  • Szigeti, Judit
    H-1043 Budapest (HU)

(74) Representative: Patentanwälte Viering, Jentschura & Partner 
Postfach 22 14 43
80504 München
80504 München (DE)

   


(54) Electrodeless low-pressure discharge lamp


(57) 5n7 The invention relates to an electrodeless low-pressure discharge lamp comprising a discharge vessel made from a light-transmitting material and having a bulb portion and a tubular cavity portion sealed in a gas-tight manner, the discharge lamp comprising furthermore an induction coil placed in the cavity portion, and a base member providing for electrical connection with the terminals of the coil and for fixing the lamp and for outer electrical contact where the discharge vessel contains a noble gas fill and additive material and its wall is provided with phosphor-containing coating.
The essential feature of the solution according to the invention is that the top surface /10/ of the tubular cavity portion /4/ is formed - over a distance of at least one-third tube radius /r/, beginning at the mantle surface /11/ of the tubular cavity portion /4/ and continuing inwardly towards the lamp axis /t/ - so that the theoretical tangential planes /s/ of the top surface /10/ make an angle /a/ exceeding 90 degrees with the lamp axis /t/ and the top surface /10/ of the tubular cavity portion /4/ has a rounded juncture with the mantle portion /11/ of the cavity portion /4/.






Search report