Resin ferrule for use in optical fiber connector and molding die therefor

Abstract

According to one aspect of the present invention, a resin ferrule, for use in an optical fiber connector, is provided including: a capillary having an axial part and a flange protruding from the axial part the ferrule having an optical fiber insertion hole axially passing through the capillary The capillary and the flange are integrated into a monolithic structure with thermoplastic resin. The capillary has a planar-shaped front end surface and a front end part extending towards the front end surface in a convergent fashion where the front end part has the outer diameter of the radial cross-section thereof reduced along the axial direction thereof towards the front end surface with the cross-section kept concentric. According to another aspect of the present invention, a die is provided for molding a resin ferrule, for use in an optical fiber connector, as defined above. The die has portions defining: a first cavity for forming the capillary a second cavity for forming the flange a core pin for forming the optical fiber insertion hole an internal hole pin for forming the front end part of the capillary and a third cavity for engaging with the internal hole pin The internal hole pin has a recess part for forming the front end part of the capillary the recess part being formed on an end surface of the internal hole pin on the side facing the first cavity The third cavity has an internal circumferential surface having a coating film made of aluminum and titanium nitride, formed thereon. The internal hole pin is engaged with the third cavity by having the coating film positioned therebetween. According to a further aspect of the present invention, the die has only a ring gate as a gate, the ring gate being disposed on an end surface of the second cavity on the side corresponding to the insertion opening of the optical fiber insertion hole With this arrangement, an excellent resin ferrule and a molding die therefor are obtained having advantages in that the ferrule is equipped with a highly increased precision, that the material and working costs of the ferrule are greatly reduced, that the ferrule has an outer diameter of high precision and is enabled to be mass produced stably, and that an optical fiber is kept free from any damage during its insertion into the ferrule.