(19)
(11) EP 0 674 339 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
23.04.1997 Bulletin 1997/17

(43) Date of publication A2:
27.09.1995 Bulletin 1995/39

(21) Application number: 95200649.2

(22) Date of filing: 17.03.1995
(51) International Patent Classification (IPC)6: H01J 65/04, H01J 61/35, H01J 61/48, H01J 61/44
(84) Designated Contracting States:
BE DE FR GB IT NL

(30) Priority: 25.03.1994 EP 94200806

(71) Applicant: Philips Electronics N.V.
5621 BA Eindhoven (NL)

(72) Inventors:
  • Schlejen, Jakob
    NL-5656 AA Eindhoven (NL)
  • Buck, Johannes Jacobus Maria
    NL-5656 AA Eindhoven (NL)
  • Roozekrans, Christianus Josephus
    NL-5656 AA Eindhoven (NL)

(74) Representative: Evers, Johannes Hubertus Maria 
INTERNATIONAAL OCTROOIBUREAU B.V, Prof. Holstlaan 6
5656 AA Eindhoven
5656 AA Eindhoven (NL)

   


(54) Electrodeless low-pressure mercury vapour discharge lamp


(57) An electrodeless low-pressure mercury vapor discharge lamp of the invention comprises a discharge vessel (1) that gas-tightly encloses a discharge-space (2) that is provided with a fill of mercury and a noble gas. The discharge vessel (1) has a light-transmitting enveloping part (3A) and further has a sunken part (3B) in which a coil (10) for generating a high-frequency magnetic field is arranged. At least a portion (5B) of a surface (4) of the discharge vessel (1) turned towards the discharge space (2) is provided with a luminescent layer (5A, 5B). At least a portion of the luminescent layer (5B) bears a protective layer (6B) of aluminum oxide particles with a covering weight of 10 to 500 µg/cm2. The protective layer provides for a lower mercury consumption and/or a reduction in the change of colour point during lamp life.






Search report