(19) |
 |
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(11) |
EP 0 442 704 A3 |
(12) |
EUROPEAN PATENT APPLICATION |
(88) |
Date of publication A3: |
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08.04.1992 Bulletin 1992/15 |
(43) |
Date of publication A2: |
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21.08.1991 Bulletin 1991/34 |
(22) |
Date of filing: 12.02.1991 |
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(84) |
Designated Contracting States: |
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DE FR GB NL |
(30) |
Priority: |
16.02.1990 JP 36457/90
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(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) |
|
|
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(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.