(19)
(11) EP 0 361 357 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
03.10.1990 Bulletin 1990/40

(43) Date of publication A2:
04.04.1990 Bulletin 1990/14

(21) Application number: 89117658.8

(22) Date of filing: 25.09.1989
(51) International Patent Classification (IPC)5: H01J 17/04, H01J 17/40
(84) Designated Contracting States:
DE FR GB

(30) Priority: 27.09.1988 JP 239639/88
25.07.1989 JP 19048/89

(71) Applicant: YAZAKI CORPORATION
Minato-ku Tokyo 108 (JP)

(72) Inventors:
  • Minamigata, Hajime
    Gotenba-shi Shizuoka 412 (JP)
  • Yagi, Kiyoshi
    Gotenba-shi Shizuoka 412 (JP)
  • Wakabayashi, Seiichi
    Gotenba-shi Shizuoka 412 (JP)

(74) Representative: Grünecker, Kinkeldey, Stockmair & Schwanhäusser Anwaltssozietät 
Maximilianstrasse 58
80538 München
80538 München (DE)


(56) References cited: : 
   
       


    (54) Discharge lamp


    (57) A discharge tube of the type wherein a voltage is applied across a pair of electrodes to cause a discharge between the anode side electrode and the cathode side electrode. In the new discharge tube, opposing end portions of said pair of electrodes are formed into a non-acute configuration, and a large number of concave or convex portions are formed on a surface at least of said cathode side electrode. A stabilized high discharge voltage can be obtained from an initial stage of discharging with a comparatively small distance between the electrodes. Further, since the surface area of the electrodes is great, exhaustion of the electrodes are dispersed, and the electrodes are superior in durability. Further, since the distance between the electrodes is small, the discharge maintaining voltage is low and the energy loss is decreased.







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