| (19) |
 |
|
(11) |
EP 0 444 591 A3 |
| (12) |
EUROPEAN PATENT APPLICATION |
| (88) |
Date of publication A3: |
|
06.11.1991 Bulletin 1991/45 |
| (43) |
Date of publication A2: |
|
04.09.1991 Bulletin 1991/36 |
| (22) |
Date of filing: 26.02.1991 |
|
| (51) |
International Patent Classification (IPC)5: H01J 61/12 |
|
| (84) |
Designated Contracting States: |
|
DE GB IT NL |
| (30) |
Priority: |
27.02.1990 JP 44414/90
|
| (71) |
Applicant: USHIO DENKI KABUSHIKI KAISHA |
|
Tokyo, 100 (JP) |
|
| (72) |
Inventors: |
|
- Ohyama, Masachika
Himeji-shi,
Hyogo (JP)
- Fuse, Tetsuo
Okayama-shi,
Okayama (JP)
- Yamaguchi, Akiyasu
Himeji-shi,
Hyogo (JP)
|
| (74) |
Representative: Kraus, Walter, Dr. et al |
|
Patentanwälte Kraus, Weisert & Partner
Thomas-Wimmer-Ring 15
D-80539 München
D-80539 München (DE) |
|
| |
|
| (54) |
Metal vapour discharge lamp |
(57) Disclosed is a metal vapor discharge lamp having mercury and iron filled therein,
in which the iron is prevented from depositing on the internal surface of the bulb
of said lamp and forming a thin iron film. Namely, in the metal vapor discharge lamp
according to this invention, the amount of thallium to be incorporated relative to
iron is 1/200 to 1/2 in terms of gram atom number ratio, whereby formation of thin
iron film can be prevented without affecting the spectrum outputs of mercury and iron.