(19)
(11) EP 1 037 257 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
07.02.2001 Bulletin 2001/06

(43) Date of publication A2:
20.09.2000 Bulletin 2000/38

(21) Application number: 00302009.6

(22) Date of filing: 13.03.2000
(51) International Patent Classification (IPC)7: H01J 61/12, H01J 61/82
(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: 11.03.1999 JP 6473299
30.07.1999 JP 21683099

(71) Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
Kadoma-shi, Osaka 571-8501 (JP)

(72) Inventors:
  • Takahashi, Kiyoshi
    Neyagawa-shi, Osaka 572-0055 (JP)
  • Horiuchi, Makoto
    Sakurai-shi, Nara 633-0062 (JP)
  • Saito, Takeshi
    Amagasaki-shi, Hyogo 661-0953 (JP)
  • Kiryu, Hideaki
    Takatsuki-shi, Osaka 569-1136 (JP)
  • Takeda, Mamoru
    Soraku-gun, Kyoto 619-0237 (JP)

(74) Representative: Dempster, Benjamin John Naftel et al
Withers & Rogers, Goldings House, 2 Hays Lane
London SE1 2HW
London SE1 2HW (GB)

   


(54) Mercury-free metal halide-lamp


(57) A lamp voltage corresponding to a lamp comprising mercury is obtained by comprising at least a rare gas, a trivalent of indium halide and a thallium iodide in an arc tube 1, and thereby a long life can be accomplished. In addition, when an enclosed amount of the trivalent of indium halide is approximately 90.0mg/cc or less per unit internal volume of the arc tube and the rare gas is xenon gas with an enclosed pressure of 2.5MPa or less, the luminous flux and the light colour most appropriate for a light source for motor vehicle headlights are obtained. Furthermore, when the thallium iodide is enclosed, the lamp voltage can be made even higher and the luminous flux can be increased.






Search report