(19)
(11) EP 0 442 704 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
08.04.1992 Bulletin 1992/15

(43) Date of publication A2:
21.08.1991 Bulletin 1991/34

(21) Application number: 91301128.4

(22) Date of filing: 12.02.1991
(51) International Patent Classification (IPC)5H01J 61/35, H01J 9/24
(84) Designated Contracting States:
DE FR GB NL

(30) Priority: 16.02.1990 JP 36457/90

(71) Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
Kadoma-shi, Osaka-fu, 571 (JP)

(72) Inventors:
  • Aoki, Masaki
    Minou-shi, Osaka-fu 562 (JP)
  • Omura, Hideaki
    Kyoto-shi, Kyoto-fu 612 (JP)
  • Ogura, Toshiaki
    Hirakata-shi, Osaka-fu 573 (JP)

(74) Representative: Crawford, Andrew Birkby et al
A.A. THORNTON & CO. Northumberland House 303-306 High Holborn
London WC1V 7LE
London WC1V 7LE (GB)


(56) References cited: : 
   
       


    (54) Metal halide lamp and method of making the same


    (57) A metal halide lamp is made by coating the inner surface of a luminous tube made of quartz glass with hafnium oxide, uranium oxide, hafnium oxide partially stabilized with yttrium oxide or uranium oxide partially stabilized with yttrium oxide by introducing therein a vapour of metal chelate containing hafnium (Hf), uranium (U) or yttrium (Y) and oxygen (O₂), nitrogen suboxide (N₂O) or ozone (O₃) as a reaction gas, and sealing the inside of the luminous tube with a halogenide of alkali metal, mercury and argon.





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