US4338111A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing a glass preform for optical fiber
Assignee: Sumitomo Electric Industries Ltd
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Filing: 1980-12-19
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Granted: 1982-07-06
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Expires: 2000-12-19
Abstract
Abstract A process for producing a preform for glass fiber for optical transmission by heating supply gases to form fine particles that are deposited on a rotating starter member to form an aggregate of fine glass particles which are then sintered to give a transparent vitreous material, characterized by a first heating stage wherein the aggregate of fine glass particles is sintered by increasing the temperature at a constant rate in a gaseous atmosphere which contains a halogen or halide and which has dehydrating activity, followed by holding the aggregate for a given period of time at a temperature in the range that causes considerable shrinkage of the aggregate, and a second heating stage where said aggregate is heated to the vitrifying temperature.
Inventors
- 👤 Takao Edahiro
- 👤 Michihisa Kyoto
- 👤 Gotaro Tanaka
- 👤 Toru Kuwahara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:36
CPC Classifications
C; C03; C03B; C03B37/00; C03B37/01; C03B37/012; C03B37/014; C03B37/01446; Y; Y10; Y10S; Y10S65/00; Y10S65/90
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
186 words
A process for producing a preform for glass fiber for optical transmission by heating supply gases to form fine glass particles that are deposited on a rotating starter member to form an aggregate of fine glass particles which are then sintered to give a transparent vitreous material, characterized by a first stage wherein the aggregate of fine glass particles is sintered in a gaseous atmosphere which contains a halogen or halide at a concentration of 1 to 10 mol% and which has dehydrating activity as the temperature is increased at a constant rate of 300° C./hr or less, followed by a period of time during which the aggregate is held at a temperature between about 950° C. and 1250° C. for at least 30 minutes that causes considerable shrinking of the aggregate and wherein the concentration of said halogen or halide is maintained at 1 to 10 mol%, and a second heating stage where said aggregate is heated to the virtrifying temperature during which second heating stage the concentration of said halogen or halide is reduced to 0 to 2% at a temperature above 1250° C.
Claim 2
Dependent Claim
186 words
A process for producing a preform for glass fiber for optical transmission by heating supply gases to form fine glass particles that are deposited on a rotating starter member to form an aggregate of fine glass particles which are then sintered to give a transparent vitreous material, characterized by a first stage wherein the aggregate of fine glass particles is sintered in a gaseous atmosphere which contains a halogen or halide at a concentration of 1 to 10 mol% and which has dehydrating activity as the temperature is increased at a constant rate of 300° C./hr or less, followed by a period of time during which the aggregate is held at a temperature between about 950° C. and 1250° C. for at least 30 minutes that causes considerable shrinking of the aggregate and wherein the concentration of said halogen or halide is maintained at 1 to 10 mol%, and a second heating stage where said aggregate is heated to the virtrifying temperature during which second heating stage the concentration of said halogen or halide is reduced to 0 to 2% at a temperature above 1250° C.
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) | 1985-07-05 | 1986-01-04 | 1986-07-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-07-05 | 1990-01-04 | 1990-07-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-07-05 | 1994-01-04 | 1994-07-06 | $7700.00 | Window Closed / Lapsed |