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US4145458A
Expired / Lapsed
US
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Method of producing internally coated glass tubes for the drawing of fiber-optic light conductors
Assignee: US Philips Corp
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Filing: 1977-09-19
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Granted: 1979-03-20
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Expires: 1997-09-19
Abstract
Abstract The change in the refractive index across the radius which is important for self-focussing fibre optic light conductors is obtained because in the plasma-activated CVD-method the oxygen content of the gas mixture and/or the temperature of the tube wall is continuously reduced during the coating procedure.
Inventors
- 👤 Jos Koenings
- 👤 Dieter Kuppers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 12:56
CPC Classifications
C; C23; C23C; C23C16/00; C23C16/44; C23C16/50; C23C16/511; C03; C03B; C03B37/00; C03B37/01; C03B37/012; C03B37/014; C03B37/018
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
108 words
A method for producing internally coated glass tubes for drawing fiber optical light conductors consisting of a core and a jacket of glasses having a mutually different refractive index, comprising the steps of passing a gas mixture containing only oxygen and a silicon halogenide through the tube to deposit a coating on the wall thereof, producing a plasma zone in the tube for energizing the reactive deposition, moving the tube relative to a device which produces a plasma and superimposes a temperature zone on the plasma zone, and continuously reducing the oxygen content of the gas mixture and/or the temperature of the tube wall while depositing the coating.
Claim 2
Independent Claim
108 words
A method for producing internally coated glass tubes for drawing fiber optical light conductors consisting of a core and a jacket of glasses having a mutually different refractive index, comprising the steps of passing a gas mixture containing only oxygen and a silicon halogenide through the tube to deposit a coating on the wall thereof, producing a plasma zone in the tube for energizing the reactive deposition, moving the tube relative to a device which produces a plasma and superimposes a temperature zone on the plasma zone, and continuously reducing the oxygen content of the gas mixture and/or the temperature of the tube wall while depositing the coating.
Claim 3
Dependent Claim
71 words
A method as claimed in claim 1, wherein at a constant silicon halogenide current in the range from 1 to 5 Ncm 3 /min and at a total pressure in the tube of between 1 and 100 Torr the oxygen current is reduced during the process from an originally 5 to 10-fold stoichiometrical excess to values near or below the stoichiometrical excess to values near or below the stoichiometrically required current.
Claim 4
Dependent Claim
45 words
A method as claimed in claim 1 wherein the temperature of the tube wall is reduced during the process in the range of between 800° and 1200° C. by 100° to 200° C., the oxygen current being 5 or 20 times the silicon halogenide current.
References Cited (Backward Citations)
GB900263A
Cited
US3655438A
Cited
DE2063726A1
Cited
JPS5040116A
Cited
US4045198A
Cited
US3980459A
Cited
US3982916A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-03-19 | 1982-09-18 | 1983-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-03-19 | 1986-09-18 | 1987-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-03-19 | 1990-09-18 | 1991-03-20 | $7700.00 | Window Closed / Lapsed |