JPS6254205A - Light connector ferrule and its manufacture - Google Patents

Abstract

PURPOSE:To easily process the optical fiber guide hole by executing the front surface hardening processing of the outer surface except the part where the guide hole is drilled. CONSTITUTION:With the machine, the edge surface part 7 of phenol base mate rial is machined to a conical shape. at a hole 5A part which is not nitrided, a rod material 8 for preventing the nitriding is fitted. Next, for the outer circum ference part of the ferrule, the front surface hardening processing is executed. Namely, for the outer circumference part of the ferrule, the ion nitriding processing is executed at the micro Vickers hardness of >=500 and depth of about 0.02mm the front surface hardened edge surface part 7 is removed by grinding and a core part 9 of the cuttable micro Vickers hardness of 160-200 is exposed. Finally, by drilling a guide hole 3A with the cutting processing, the ferrule can be completed.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an optical connector in which a pair of opposing ferrules are aligned using a sleeve to align the axes of the optical fiber cores, and in particular, the present invention relates to an optical connector that aligns a pair of opposing ferrules using a sleeve to align the axes of the optical fiber cores. This invention relates to an optical connector ferrule that prevents deterioration of connection characteristics due to surface scratches, dents, etc., and a method for manufacturing the same.

(Conventional technology) FIG. 4 is a schematic diagram showing the connection principle of the optical connector.

At one end of the ferrule bodies IA and IB, an optical fiber wire 2A. Guide holes 3A, 3B for attaching optical fibers 4A, 2B are provided at the center, and optical fiber coating parts 4A, 3B are provided coaxially. 4
Holes 5A and 5B for mounting B are provided. The ferrule bodies IA, IB are press-fitted into the sleeve 6 and their end surfaces are brought into contact to connect optical signals.

Therefore, if misalignment occurs between the optical fibers, the amount of light will attenuate and connection loss will occur. For example, in a single mode optical fiber, a misalignment of 2 μm causes a splice loss of about 1 decibel. Therefore, the ferrule must be manufactured by ultra-precision machining so that the outer guide hole diameter and eccentricity are each within 1 μm.

(Problems to be Solved by the Invention) Stainless steel is used as a material for such a ferrule. Since stainless steel is relatively soft with a micro Vickers hardness of 160 to 200, scratches and dents are likely to occur due to sliding during attachment and detachment of the ferrule and handling.

If the inner and outer circumferences of the ferrule are hardened to prevent this, there is a problem in that precision machining, including the guide holes, becomes difficult and mass production is not possible.

On the other hand, in the case of ferrules that are required to have dimensional accuracy within 1 μm as mentioned above, scratches of a few μm or unevenness due to surface dents of 10 μm or more occur due to surface hardness during attachment/detachment or handling. It has been proven that this cannot be prevented unless the micro-Vickers hardness is increased to 500 or more.

In order to solve the above-mentioned problems, an object of the present invention is to provide an optical connector ferrule in which the outer circumferential surface of the ferrule is surface hardened to a micro-Vickers hardness of 500 or more, and which enables the machining of an optical fiber guide hole, and a method for manufacturing the same. Our goal is to provide the following.

(Means for Solving the Problems) In order to achieve the above object, an optical connector ferrule according to the present invention is provided with a guide hole for mounting an optical fiber at the center of one end, in which the guide hole is The outer surface other than the part to be drilled has been surface hardened.

Furthermore, in order to achieve the above object, a method for manufacturing an optical connector ferrule according to the present invention provides a method for manufacturing an optical connector ferrule having a guide hole for mounting an optical fiber at the center of one end, wherein one end of the ferrule is formed into a conical shape. a step of surface hardening the outer circumferential surface of the ferrule, a step of polishing and removing the hardened layer on the end surface of the conical guide hole, and forming a guide hole on the removed end surface of the ferrule. The process consists of a step of drilling a hole.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings and the like.

Fig. 1 is a cross-sectional view showing the processing procedure of the optical connector ferrule according to the present invention, Fig. 1 (A) is a state diagram of ion nitrided state, and Fig. 1 (B) is a surface hardened portion of the end surface of the guide hole. FIG. 1(C) is a diagram showing the completed state with the parts removed.

In FIG. 1, IA is a ferrule, 5A is a hole provided in ferrule IA, 7 is the tip of ferrule IA,
8 is Rondo material.

First, as a processing procedure, the end face portion 7 is machined into a conical shape by machining the ferrule base material shape as shown in FIG. 1(A). In the hole 5A section which should not be nitrided,
A rond material 8 for preventing nitriding is fitted.

Next, the outer peripheral portion of the ferrule is subjected to surface hardening treatment. Although there are various methods for surface hardening, the present invention employs an ion nitriding method.

This is because the ion nitriding method can be processed at a relatively low temperature (500 to 550°C), requires a relatively short processing time (1 to 2 hours), and is also advantageous in terms of deformation strain. . In addition to the ion nitriding method, a gas nitriding method and a carburizing and hardening method can be employed.

FIG. 2 shows an ion-nitrided ferrule according to the present invention (
It is a diagram showing the hardening depth of the material (made of material 5US304).

In this example, the outer peripheral portion of the ferrule is subjected to ion nitriding treatment to a micro Vickers hardness of 500 or more and a depth of approximately 0.02 ms (portion indicated by double hunting).

Furthermore, as shown in FIG. 1(B), the surface-hardened end surface portion 7 is removed by grinding to expose the core portion 9 which can be cut and has a micro-Vickers hardness of 160 to 200.

Finally, as shown in FIG. 1(C), the ferrule can be completed by drilling a guide hole 3A by cutting.

Please note that the outer peripheral surface will become slightly rough due to the hardening process, so
．． It is necessary to finish by grinding to about 0.005 mm.

FIG. 3 is a diagram showing another embodiment of the optical connector ferrule according to the present invention.

This embodiment is an optical connector ferrule in which the surface of a metal tube 10 is hardened and a capillary 12 having a guide hole 11 in the threaded portion of the hole in the inner circumference of the metal tube 10 is formed by resin molding.

For the capillary 12, for example, in addition to plastic, glass, soft metal, ceramic, etc. can be used. Further, the metal tube 10 may be entirely hardened.

(Effects of the Invention) As described above in detail, according to the present invention, the outer peripheral surface of the ferrule can be hardened to a Vickers hardness of 500 or more, and the optical fiber guide hole can be easily processed under conventional processing conditions. This has made it possible to mass-produce optical fiber ferrules that can prevent scratches and dents caused by attachment and detachment, eliminate sudden deterioration of connection characteristics, and maintain stable reproducibility over a long period of time. Ta.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing the processing procedure of the optical connector ferrule according to the present invention, Fig. 1 (A) is a state diagram of ion nitrided state, and Fig. 1 (B) is a surface hardened portion of the end surface of the guide hole. FIG. 1(C) is a completed state diagram with . FIG. 2 is a diagram showing the hardening depth of an ion-nitrided ferrule according to the present invention. FIG. 3 is a diagram showing another embodiment of the optical connector ferrule according to the present invention. FIG. 4 is a schematic diagram showing the connection principle of the optical connector. IA, IB... Ferrule body 2A, 2B... Optical fiber wire 3A, 3B... Guide hole 4A, 4B... Covering 5
A, 5B...hole 6...sleeve 7...
End part 8... Rondo material 9... Core part

Claims (3)

[Claims] (1) An optical connector ferrule having a guide hole for mounting an optical fiber at the center of one end, characterized in that the outer surface of the outer surface other than the part where the guide hole is bored is subjected to surface hardening treatment. Ferrule. (2) In a method for manufacturing an optical connector ferrule having a guide hole for installing an optical fiber in the center of one end,
a step of machining one end of the ferrule into a conical shape; a step of surface hardening the outer circumferential surface of the ferrule; a step of polishing and removing the hardened layer on the end surface of the conical guide hole; and the removal of the ferrule. 1. A method for manufacturing an optical connector ferrule, comprising the step of drilling a guide hole in an end surface of the ferrule. (3) The optical connector ferrule according to claim 2, wherein the surface hardening treatment is performed on the stainless steel ferrule by ion nitriding to give a micro Vickers hardness of 500 or more and a hardening depth of about 0.05 mm or less. Production method.