Patent US4441047A successfully refreshed from Google Patents.
US4441047A
Expired / Lapsed
US
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Electrostatic silica coating for electric lamps
Assignee: General Electric Co
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Filing: 1981-12-07
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Granted: 1984-04-03
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Expires: 2001-12-07
Abstract
Abstract A silica powder mixture is disclosed for electrostatic deposition to provide diffuse light from electric lamps. The present powder mixture exhibits improved moisture resistance along with shelf life and comprises in weight proportions approximately 35-65 parts calcined diatomaceous silica, approximately 35-65 parts fumed silica, and approximately 5-15 parts colloidal hydrophobic silica.
Inventors
- 👤 Clifford B. Collins
- 👤 William G. James
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 10:24
CPC Classifications
H; H01; H01K; H01K1/00; H01K1/28; H01K1/32
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
89 words
An electric lamp comprising a bulb having a light diffusing coating on the inside surface thereof comprising an electrostatically deposited powder comprising in parts by weight approximately 35-65 parts flux calcined diatomaceous silica, approximately 35-65 parts fumed silica, and approximately 5-15 parts colloidal hydrophobic silica, said powder having a Coulter particle size between 1 and 6 microns with electrical conductivity in the range from 1×10 -4 to 2.3×10 -7 amperes at an applied voltage of 7 kilovolts and 3×10 -4 to 4×10 -9 amperes at 2 kilovolts applied voltage.
Claim 2
Dependent Claim
89 words
An electric lamp comprising a bulb having a light diffusing coating on the inside surface thereof comprising an electrostatically deposited powder comprising in parts by weight approximately 35-65 parts flux calcined diatomaceous silica, approximately 35-65 parts fumed silica, and approximately 5-15 parts colloidal hydrophobic silica, said powder having a Coulter particle size between 1 and 6 microns with electrical conductivity in the range from 1×10 -4 to 2.3×10 -7 amperes at an applied voltage of 7 kilovolts and 3×10 -4 to 4×10 -9 amperes at 2 kilovolts applied voltage.
Claim 3
Dependent Claim
20 words
The lamp of claim 1 wherein the moisture content of the fumed silica does not exceed about 1% by weight.
Claim 4
Dependent Claim
23 words
The lamp of claim 1 wherein the surface area for the fumed silica resides in the approximate range 40-70 square meters per gram.
Claim 5
Dependent Claim
24 words
The lamp of claim 1 wherein the surface area for the colloidal hydrophobic silica resides in the approximate range 100-300 square meters per gram.
Claim 6
Dependent Claim
17 words
The lamp of claim 1 wherein the electrical resistivity of the fumed silica exceeds 10 12 ohm-centimeters.
Claim 7
Dependent Claim
26 words
The lamp of claim 1 wherein the moisture content and surface area of the flux calcined diatomaceous silica is less than that of the fumed silica.
References Cited (Backward Citations)
US4081709A
Cited
US4099080A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-04-03 | 1987-10-03 | 1988-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-04-03 | 1991-10-03 | 1992-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-04-03 | 1995-10-03 | 1996-04-03 | $7700.00 | Window Closed / Lapsed |