US3912959A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High pressure sodium vapor discharge lamps
Assignee: Hitachi Ltd
•
Filing: 1973-03-16
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Granted: 1975-10-14
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Expires: 1993-03-16
Abstract
Abstract A ceramic tube consisting of sintered high transparent polycrystalline yttria is used as an envelope in a high pressure sodium vapor discharge lamp. The discharge lamp having this envelope excels in operation for a long period of time because the transparency of this envelope is not reduced at all when it is exposed to saturated sodium vapor at elevated temperatures.
Inventors
- 👤 Akinori Muta
- 👤 Yasuo Tsukuda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 08:40
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/50; C04B35/505; H; H01; H01J; H01J61/00; H01J61/02; H01J61/30; H01J61/302
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
54 words
A HIGH PRESSRE SODIUM VAPOR DISCHARGE LAMP COMPRISING: A TUBLAR ELONGATED ENVELOPE OFSINTERED POLYCRYSTALLINE YTTRIA CONSISTING OF CORROSION RESISTANT YTTRIUM OXIDE AND HAVING AN AVERAGE GRAIN SIZE OF 0.1 TO 5 MM, SAID ENVELOPE HAVING A PAIR OF ELECTRODES SEALED INTO OPPOSITE ENDS, AND AN IONIZABLE MEDIUM INCLUDING SODIUM VAPOR SEALED WITHIN SAID ENVELOPE.
Claim 2
Dependent Claim
54 words
A HIGH PRESSRE SODIUM VAPOR DISCHARGE LAMP COMPRISING: A TUBLAR ELONGATED ENVELOPE OFSINTERED POLYCRYSTALLINE YTTRIA CONSISTING OF CORROSION RESISTANT YTTRIUM OXIDE AND HAVING AN AVERAGE GRAIN SIZE OF 0.1 TO 5 MM, SAID ENVELOPE HAVING A PAIR OF ELECTRODES SEALED INTO OPPOSITE ENDS, AND AN IONIZABLE MEDIUM INCLUDING SODIUM VAPOR SEALED WITHIN SAID ENVELOPE.
Claim 3
Dependent Claim
30 words
The high pressure sodium vapor discharge lamp according to claim 1, in which said envelope has a heat resistant oxide layer coated on the outer sides of opposite ends thereof.
Claim 4
Dependent Claim
28 words
The high pressure sodium vapor discharge lamp according to claim 2, in which said heat resistant oxide layer is selected from the group consisting of alumina and yttria.
Claim 5
Dependent Claim
37 words
The high pressure sodium vapor discharge lamp according to claim 1 wherein the thickness of the ends of said envelope in which said electrodes are sealed is greater than the thickness of the side of said envelope.
Claim 6
Dependent Claim
37 words
The high pressure sodium vapor discharge lamp according to claim 1 wherein a powdered heat-resistant material is coated on the outside of the opposite ends of said envelope up to the height of the electrodes sealed therein.
Claim 7
Dependent Claim
32 words
The high pressure sodium vapor discharge lamp according to claim 1, in which the corrosion resistant yttrium oxide of said envelope has an average grain size of 0.2 mm to 5 mm.
Claim 8
Dependent Claim
32 words
The high pressure sodium vapor discharge lamp according to claim 1, in which the Corrosion resistant yttrium oxide of said envelope has an average grain size of 0.3 mm to 5 mm.
References Cited (Backward Citations)
US3363134A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-10-13 | 1979-04-14 | 1979-10-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-13 | 1983-04-14 | 1983-10-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-13 | 1987-04-14 | 1987-10-14 | $7700.00 | Window Closed / Lapsed |