Patent US4298364A successfully refreshed from Google Patents.
US4298364A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making optical fibers having improved core roundness
Assignee: Corning Glass Works
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Filing: 1980-03-17
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Granted: 1981-11-03
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Expires: 2000-03-17
Abstract
Abstract A method of producing optical fibers having improved core roundness and core-clad axis concentricity. Prior to the step of forming a layer of core material on the inner surface of a bait tube, the tube is pressurized and heated and shrunk at least 1 mm and thereafter the pressure is increased to inflate the tube until the outside diameter thereof approximates that of the originally provided bait tube.
Inventors
- 👤 Paul E. Blaszyk
- 👤 Susan F. Murphy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 12:59
CPC Classifications
C; C03; C03B; C03B37/00; C03B37/01; C03B37/012; C03B37/014; C03B37/018; C03B37/01861; C03B23/00; C03B23/04; C03B23/07; Y; Y02; Y02P; Y02P40/00; Y02P40/50; Y02P40/57
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
138 words
In the method of manufacturing an optical waveguide preform which includes the steps of providing a cylindrical glass bait tube, and forming at least one layer of glass on the inner surface thereof, the improvement which comprises subjecting said bait tube to the following steps prior to the time said layer is formed: heating said bait tube, providing a positive pressure within said bait tube, decreasing the diameter of said bait tube by at least one mm to form a shrunken tube, and increasing the pressure within said shrunken bait tube so that the tube diameter increases to at least one mm greater than the diameter of said bait tube in its shrunken state to form an expanded bait tube, thereby improving the roundness of said bait tube without detrimentally affecting the uniformity of the tube wall thickness.
Claim 2
Dependent Claim
138 words
In the method of manufacturing an optical waveguide preform which includes the steps of providing a cylindrical glass bait tube, and forming at least one layer of glass on the inner surface thereof, the improvement which comprises subjecting said bait tube to the following steps prior to the time said layer is formed: heating said bait tube, providing a positive pressure within said bait tube, decreasing the diameter of said bait tube by at least one mm to form a shrunken tube, and increasing the pressure within said shrunken bait tube so that the tube diameter increases to at least one mm greater than the diameter of said bait tube in its shrunken state to form an expanded bait tube, thereby improving the roundness of said bait tube without detrimentally affecting the uniformity of the tube wall thickness.
Claim 3
Dependent Claim
28 words
A method in accordance with claim 1 wherein the diameter of said inflated bait tube is about equal to that of said originally provided cylindrical glass bait tube.
Claim 4
Dependent Claim
26 words
A method in accordance with claim 1 wherein the diameter of said inflated tube is less than that of the originally provided cylindrical glass bait tube.
Claim 5
Dependent Claim
57 words
A method in accordance with claim 1 wherein the diameter of said shrunken tube is between 2 and 4 mm less than that of the originally provided cylindrical glass bait tube and wherein the diameter of said inflated bait tube is between 2 and 4 mm greater than that of the diameter of said shrunken bait tube.
Claim 6
Dependent Claim
60 words
A method in accordance with claim 4 wherein, after the step of increasing the pressure within said bait tube to form an inflated bait tube, the following steps are performed: forming at least one layer of core material on the inner surface of said inflated bait tube, reducing the diameter of said preform, and drawing said preform into a fiber.
Claim 7
Dependent Claim
40 words
A method in accordance with claim 4 wherein, during the step of decreasing the diameter of said bait tube, the pressure within said tube is from 0.02 to 5.0 mm Hg greater than that of the region surrounding said tube.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-11-02 | 1985-05-04 | 1985-11-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-11-02 | 1989-05-04 | 1989-11-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-11-02 | 1993-05-04 | 1993-11-03 | $7700.00 | Window Closed / Lapsed |