The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 01, 2019
Filed:
Aug. 10, 2016
Fujikura Ltd., Tokyo, JP;
Akihito Imase, Sakura, JP;
FUJIKURA LTD., Tokyo, JP;
Abstract
An optical fiber manufacturing method includes: melting and drawing an optical fiber preform to form a glass fiber; cooling the glass fiber while inserting the glass fiber into a tubular slow-cooling device from an inlet end toward an outlet end thereof; and lowering an inner wall temperature of the slow-cooling device below a temperature of the glass fiber and providing a pressure gradient in which a pressure increases in a direction from the inlet end toward the outlet end inside the slow-cooling device when cooling the glass fiber, wherein the average pressure change dP/dL in a moving direction of the glass fiber inside the slow-cooling device satisfies the following Formula (1) when the tube inner diameter of the slow-cooling device is defined as D [m] and the length of an internal space of the slow-cooling device in the moving direction of the glass fiber is defined as L [m].(π/4)×≤0.03  (1)