US3759602A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Inhibiting d-c notching effect in incandescent lamp filaments
Assignee: General Electric Co
•
Filing: 1971-08-30
•
Granted: 1973-09-18
•
Expires: 1991-08-30
Abstract
Abstract Process and product produced thereby wherein the problem of ''''dc notching'''' and resulting premature failure of tungsten, tantalum or molybdenum metal filaments for miniature lamps operating below 2400*C is avoided by steps which include: removal of reactive gases including residual chemically available oxygen and nitrogen by high vacuum, heating the filament to help drive off the reactive gases, flushing out at least once and backfilling the bulb envelope with a heavy inert gas from Group VIIIA of the periodic table.
Inventors
- 👤 J Walter
- 👤 M Gigliotti
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 15:31
CPC Classifications
H; H01; H01K; H01K3/00; H01K3/02
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
12 words
The method according to claim 1 wherein the inert gas is argon.
References Cited (Backward Citations)
US453742A
Cited
US1180159A
Cited
US1594057A
Cited
US1630128A
Cited
US1895855A
Cited
US2060657A
Cited
US2115480A
Cited
US2098907A
Cited
US2235713A
Cited
US2482447A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-17 | 1977-03-19 | 1977-09-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-17 | 1981-03-19 | 1981-09-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-17 | 1985-03-19 | 1985-09-18 | $7700.00 | Window Closed / Lapsed |