(19)
(11) EP 0 507 533 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
07.01.1993 Bulletin 1993/01

(43) Date of publication A2:
07.10.1992 Bulletin 1992/41

(21) Application number: 92302784.1

(22) Date of filing: 30.03.1992
(51) International Patent Classification (IPC)5: H01J 65/00, H01J 61/82, H01J 61/35, H01J 61/24
(84) Designated Contracting States:
DE FR GB

(30) Priority: 30.03.1991 JP 93683/91

(71) Applicant: TOSHIBA LIGHTING & TECHNOLOGY CORPORATION
Minato-ku, Tokyo-To (JP)

(72) Inventor:
  • Inoue, Akihiro
    Chigasaki-shi, Kanagawa-ken (JP)

(74) Representative: Muir, Ian R. et al
HASELTINE LAKE & CO. Hazlitt House 28 Southampton Buildings Chancery Lane
London WC2A 1AT
London WC2A 1AT (GB)


(56) References cited: : 
   
       


    (54) A mercury-free electrodeless metal halide lamp


    (57) A mercury-free electrodeless metal halide lamp has an arc tube (21). The arc tube (21) is made of glass having an inner surface defining an arc discharge space (23). A metal oxide layer (31, 35) is coated on the inner surface of the arc tube (21). A filling gas disposed in the arc discharge space (23) includes metal halide and a rare gas. Excitation means (27,29) couple radio-frequency energy to the filling gas for generating an arc discharge. The mercury-free electrodeless metal halide lamp suppresses an increase of an arc voltage of the lamp during its lifetime.






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