(19)
(11) EP 0 926 700 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
08.12.1999 Bulletin 1999/49

(43) Date of publication A2:
30.06.1999 Bulletin 1999/26

(21) Application number: 98310549.5

(22) Date of filing: 22.12.1998
(51) International Patent Classification (IPC)6: H01J 61/073, H01J 9/02
(84) Designated Contracting States:
AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE
Designated Extension States:
AL LT LV MK RO SI

(30) Priority: 24.12.1997 US 998311
26.08.1998 US 140587

(71) Applicant: NGK INSULATORS, LTD.
Nagoya City Aichi Pref. (JP)

(72) Inventor:
  • Niimi, Norikazu
    Kasugai City, Aichi Pref. (JP)

(74) Representative: Paget, Hugh Charles Edward et al
MEWBURN ELLIS York House 23 Kingsway
London WC2B 6HP
London WC2B 6HP (GB)

   


(54) High pressure discharge lamp


(57) A vessel (4) has a main body (10) and a plugging member (11a) made of alumina. A composite electrode (6a) has a cylindrical current conductor having substantially the same diameter as the opening at one end of the vessel, and an electrode (14a) joined by welding at the end of the current conductor exposed to inside of the vessel. The current conductor of the composite electrode has a cylindrical member (13a) made of alumina and a metallization layer made of molybdenum and alumina. The vessel and the composite electrode have bene subjected to co-firing into an integrated body, with the composite electrode inserted into the opening portion at one end of the vessel so that the electrode is exposed to the inner space with one end of the composite electrode exposed outside of the vessel.






Search report