Methods of and apparatus for collapsing a preform tube into a preform from which lightguide fiber is drawn
US4486214A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Dec 8, 1983 |
| Grant date | Dec 4, 1984 |
| Priority date | — |
| Expiry date | Dec 8, 2003 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC03B23/055
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A lightguide fiber preform is made by depositing optically suitable layers of doped silicon dioxide on an inner wall of a rotating glass substrate tube (31) which is exposed to a moving zone of heat during a deposition mode and during a mode when the tube is collapsed. During each of a plurality of passes of a torch assembly (50) in the collapse mode following deposition, a contact device (101) is in continuous engagement with the tube and is caused to apply forces to each successive increment of its length following exposure to at least an initial portion of the zone of heat to collapse incrementally the tube. Between successive ones of the plurality of passes, the contact device is moved inwardly of the tube so that each increment of length is exposed to forces which as between the successive passes are applied at points incrementally closer to the longitudinal axis (36) of the tube.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.