US4296352A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Incandescent lamp
Assignee: General Electric Co
•
Filing: 1979-12-19
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Granted: 1981-10-20
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Expires: 1999-12-19
Abstract
Abstract An improved incandescent lamp filament is described having an inner core of doped tungsten crystals with a surface layer of chemically vapor deposited undoped tungsten crystals. The inner core material exhibits the sag-resistant grain structure obtained with dispersion alloy products of tungsten whereas the unalloyed tungsten crystals in the surface layer are of a finer size and can further exhibit a preferred crystallographic orientation. Incandescent lamps utilizing said improved tungsten filaments exhibit increased vibration resistance and greater notch resistance when operated on direct current.
Inventors
- 👤 Ivan Berlec
- 👤 Lewis V. McCarty
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 11:24
CPC Classifications
H; H01; H01K; H01K1/00; H01K1/02; H01K1/04
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
59 words
An incandescent lamp filament comprising a tungsten wire having an inner core of tungsten crystals doped with grain growth promoting additives selected from aluminum, silicon and potassium compounds to exhibit sag resistance and a surface layer of chemically vapor deposited undoped tungsten crystals imparting increased vibration damping and lower shear modulus value at elevated temperatures to the lamp filament.
Claim 2
Dependent Claim
59 words
An incandescent lamp filament comprising a tungsten wire having an inner core of tungsten crystals doped with grain growth promoting additives selected from aluminum, silicon and potassium compounds to exhibit sag resistance and a surface layer of chemically vapor deposited undoped tungsten crystals imparting increased vibration damping and lower shear modulus value at elevated temperatures to the lamp filament.
Claim 3
Dependent Claim
38 words
An incandescent lamp filament as in claim 1 wherein the vapor deposited undoped tungsten crystals are of smaller size than the doped tungsten crystals as well as having a preferred crystallographic orientation transverse to the filament longitudinal axis.
Claim 4
Dependent Claim
31 words
An incandescent lamp filament as in claim 1 wherein the vapor deposited undoped crystals are of smaller size than the doped tungsten crystals as well as having an equiaxed crystallographic structure.
Claim 5
Dependent Claim
12 words
An incandescent lamp filament as in claim 1 having a coil configuration.
Claim 6
Dependent Claim
17 words
An incandescent lamp filament as in claim 4 wherein said coil configuration was obtained at elevated temperature.
Claim 7
Dependent Claim
17 words
An incandescent lamp filament as in claim 5 wherein said coil configuration was obtained at elevated temperatures.
Claim 8
Dependent Claim
23 words
An incandescent lamp filament as in claim 3 which was drawn to a smaller size diameter after deposition of the undoped tungsten crystals.
Claim 9
Dependent Claim
23 words
An incandescent lamp filament as in claim 1 wherein the thickness of the deposited undoped tungsten crystals is at least about 0.0002 inch.
Claim 10
Dependent Claim
18 words
An incandescent lamp filament as in claim 2 wherein the doped tungsten crystals contain grain growth promoting additives.
Claim 11
Dependent Claim
68 words
An incandescent lamp having a transparent envelope which contains a tungsten filament comprising a tungsten wire having an inner core of tungsten crystals doped with grain growth promoting additives selected from aluminum, silicon and potassium compounds to exhibit sag resistance and a surface layer of chemically deposited undoped tungsten crystals imparting increased vibration damping and a lower shear modulus value at elevated temperatures to improve the vibration resistance.
Claim 12
Dependent Claim
68 words
An incandescent lamp having a transparent envelope which contains a tungsten filament comprising a tungsten wire having an inner core of tungsten crystals doped with grain growth promoting additives selected from aluminum, silicon and potassium compounds to exhibit sag resistance and a surface layer of chemically deposited undoped tungsten crystals imparting increased vibration damping and a lower shear modulus value at elevated temperatures to improve the vibration resistance.
Claim 13
Dependent Claim
13 words
An incandescent lamp as in claim 10 wherein said transparent envelope is glass.
Claim 14
Dependent Claim
15 words
An incandescent lamp as in claim 10 wherein said tungsten filament has a coil configuration.
Claim 15
Dependent Claim
24 words
An incandescent lamp as in claim 11 wherein said tungsten filament is electrically connected to inlead support means hermetically sealed to the glass envelope.
Claim 16
Dependent Claim
16 words
An incandescent lamp as in claim 10 exhibiting improved notch resistance when operated on direct current.
Claim 17
Dependent Claim
37 words
An incandescent lamp as in claim 10 wherein the vapor deposited undoped tungsten crystals are of smaller size than the doped tungsten crystals as well as having a preferred crystallographic orientation transverse to the filament longitudinal axis.
Claim 18
Dependent Claim
31 words
An incandescent lamp as in claim 10 wherein the vapor deposited undoped tungsten crystals are of smaller size than the doped tungsten crystals as well as having an equiaxed crystallographic structure.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-10-19 | 1985-04-20 | 1985-10-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-10-19 | 1989-04-20 | 1989-10-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-10-19 | 1993-04-20 | 1993-10-20 | $7700.00 | Window Closed / Lapsed |