Patent US3386132A successfully refreshed from Google Patents.
US3830640A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of light-conducting glass structures with index gradient
Assignee: Nippon Selfoc Co Ltd
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Filing: 1972-12-04
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Granted: 1974-08-20
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Expires: 1992-12-04
Abstract
Abstract A light-conducting glass rod is passed continuously through a furnace wherein it is heated to a temperature above its softening point and is stretched into a thin filament. The rod has a refractive index gradient in any transverse cross-section such that the index decreases progressively or continuously from the central axis outward towards the periphery and this gradient is increased in the filament by the stretching. The heating and stretching may also be carried out by concentrically disposing a glass tube around the light-conducting glass rod and evacuating the interior of the glass tube to thereby produce a lightconducting filament having a covering layer. The filament thus produced may be subjected to a simple thermochemical treatment to increase its strength and several pieces of the filament may be bundled together to produce an ommateal lens.
Inventors
- 👤 Y Ikeda
- 👤 H Matsumura
- 👤 I Kitano
- 👤 K Koizumi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 06:42
CPC Classifications
C; C03; C03C; C03C25/00; C03C25/10; C03C25/104; C03B; C03B37/00; C03B37/01; C03B37/02; C03B37/025; C03B37/027; C03C13/00; C03C13/04; C03C21/00
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
66 words
A method according to claim 1; wherein said advancing step comprises longitudinally advancing said glass rod at a predetermined constant speed into said treating zone and withdrawing said glass rod at a higher predetermined constant speed from said treating zone to thereby continuously apply a constant tensile force to said plastically deformable glass rod of sufficient strength to stretch said glass rod into said glass fiber.
Claim 2
Dependent Claim
26 words
A method according to claim 1; wherein the length of said glass fiber is at least 10 times greater than said given length of said rod.
Claim 3
Dependent Claim
111 words
A method according to claim 1; including providing a glass tube having a diameter no less than said given diameter; concentrically disposing said glass rod within said glass tube to form a glass composite prior to said advancing step; said advancing step comprising longitudinally advancing said glass composite through said treating zone while applying said tensile force thereto; and wherein said heating step includes heating said glass composite to a temperature sufficient to render both said glass tube and glass rod plastically deformable to effect longitudinal stretching of the plastically deformable composite into said glass fiber having exteriorly disposed therearound and adhered thereto a protective coating composed of said glass tube.
Claim 4
Dependent Claim
32 words
A method according to claim 4; including maintaining the space existing between the concentrically disposed glass rod and glass tube under vacuum during said heating and stretching to facilitate their bonding together.
Claim 5
Independent Claim
233 words
A method of producing a light-conducting glass fiber from a glass rod comprising: providing a glass rod having a given length, a center axis, a given diameter, and having as viewed in any cross-section thereof perpendicular to said center axis a given refractive index no at said center axis, a given refractive index n1 at the outer periphery and a given refractive index gradient between no and n1; longitudinally advancing said glass rod through a treating zone by advancing said glass rod into said treating zone at a given speed and withdrawing said glass rod from said treating zone at a speed greater said given speed to thereby apply a tensile force to said glass rod in the longitudinal direction thereof; and heating said glass rod during advancement thereof through said treating zone to a temperature sufficient to render said glass rod plastically deformable during application of said tensile force to the plastically deformable glass rod to effect longitudinal stretching of said glass rod into a glass fiber having said center axis, a length substantially longer than said given length, a diameter smaller than said given diameter, and having a refractive index value at said center axis substantially equal to said given refractive index no, a refractive index value at the outer periphery substantially equal to said given refractive index n1 and a refractive index gradient index steeper than said refractive index gradient.
Claim 6
Dependent Claim
64 words
A method according to claim 6; wherein said advancing step comprises longitudinally advancing said glass rod at a predetermined constant speed into said treating zone and withdrawing said glass rod at a higher predetermined constant speed from said treating zone to thereby a constant tensile force to said plastically deformable glass rod of sufficient strength to stretch said glass rod into said glass fiber.
Claim 7
Dependent Claim
111 words
A method according to claim 6; including providing a glass tube having a diameter no less than said given diameter; concentrically disposing said glass rod within said glass tube to form a glass composite prior to said advancing step; said advancing step comprising longitudinally advancing said glass composite through said treating zone while applying said tensile force thereto; and wherein said heating step includes heating said glass composite to a temperature sufficient to render both said glass tube and glass rod plastically deformable to effect longitudinal stretching of the plastically deformable composite into said glass fiber having exteriorly disposed therearound and adhered thereto a protective coating composed of said glass tube.
Claim 8
Dependent Claim
32 words
A method according to claim 8; including maintaining the spaced existing between the concentrically dispsoed glass rod and glass tube under vacuum during said heating and stretching to facilitate their bonding together.
Claim 9
Dependent Claim
27 words
A method according to claim 6; wherein the length of said glass fiber is at least 10 times greater than said given length of said glass rod.
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) | 1977-08-19 | 1978-02-18 | 1978-08-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-08-19 | 1982-02-18 | 1982-08-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-08-19 | 1986-02-18 | 1986-08-20 | $7700.00 | Window Closed / Lapsed |