JP4095883B2

JP4095883B2 - Polishing method for slant PC connector ferrule

Info

Publication number: JP4095883B2
Application number: JP2002334519A
Authority: JP
Inventors: 浩二皆見; 淳司平; 亮長瀬; 秀一 ▲柳▼; 治村田; 泰世三宅; 雄二品川; 正次諏訪部; 英和尾之内
Original assignee: Seikoh Giken Co Ltd; NTT Advanced Technology Corp; Nippon Telegraph and Telephone Corp; NTT Inc USA
Current assignee: Seikoh Giken Co Ltd; NTT Advanced Technology Corp; NTT Inc; NTT Inc USA
Priority date: 2002-11-19
Filing date: 2002-11-19
Publication date: 2008-06-04
Anticipated expiration: 2022-11-19
Also published as: JP2004170563A

Description

【０００１】
【発明の属する技術分野】
本発明は、光ファイバの斜め研磨端面同士を接続する斜めＰＣコネクタに用いられるフェルール研磨方法に関する。
【０００２】
【従来の技術】
光通信等において用いられる光コネクタでは、コネクタ接続部における接続損失の低減及び反射戻り光の低減を目的として、フェルールに保持された光ファイバの端面をフェルール端面と共に光ファイバの軸に垂直な面に対して斜めに、且つ凸球面に研磨した「斜めＰＣ（ＰｈｙｓｉｃａｌＣｏｎｔａｃｔ）コネクタ」が用いられる。
【０００３】
ここで、従来のＭＵ型の斜めＰＣコネクタに用いられるフェルールについて説明する。
【０００４】
図１２は、従来技術に係るフェルールの斜視図及び平面図である。
【０００５】
図１２に示すように、斜めＰＣコネクタに用いられるフェルール３１０は、先端面３２３が軸と直交する面に対して傾斜した凸球面状に設けられた円筒形状を有するフェルール用筒状体３２０と、フェルール用筒状体３２０の後端部に嵌合するつば部材３３０とからなり、つば部材３３０には、フェルール用筒状体３１０側の外周に円周方向に亘って半径方向に突出したつば部３３３が設けられている。このつば部３３３は、半径方向の断面が略矩形状に形成されており、フェルール３１０が斜めＰＣコネクタのプラグフレームに保持された際にプラグフレーム内に設けられたつば部３３３と同等の形状で形成された係合孔と係合してフェルール３１０の中心軸回りの回転方向の移動を規制している。
【０００６】
このようなフェルール３１０は、プラグフレーム内に保持されて光コネクタアダプタ等により、フェルール用筒状体３２０の先端面３２３同士を当接させた対向接続を行うことにより、低挿入損失及び高反射減衰量の光接続を行うことができる。
【０００７】
このような斜めＰＣコネクタ用のフェルール３１０は、端面研磨装置によってその先端面３２３を光ファイバ軸に垂直な面に対して傾斜した凸球面状に形成することができる。
【０００８】
この端面研磨装置は、回転及び揺動する研磨定盤上に載置された弾性部材上の研磨部材に、治具盤に斜めＰＣコネクタの後端部側が研磨部材の研磨面に垂直な方向に対して研磨定盤の回転中心に向かって傾斜するように保持させて、斜めＰＣコネクタのフェルール３１０の先端面を研磨部材に押圧して研磨することで形成することができる（例えば、特許文献１参照。）。
【０００９】
【特許文献１】
特開平８−１１２７４５号公報（第３頁、第１図）
【００１０】
【発明が解決しようとする課題】
しかしながら、このように形成された斜めＰＣコネクタ用のフェルールは、対向接続させた際に、挿入損失を低減すると共に反射減衰量を高めるために、フェルール用筒状体の凸球面状の先端面の頂点が光ファイバの先端面の中心軸から所定の範囲の位置、例えば、５０μｍ以下となるように形成しなくてはならず、高精度に形成するのは困難であるという問題がある。ここで斜めＰＣコネクタ用のフェルールの先端面の頂点のフェルールの中心からのずれは、ＪＩＳＣ５９６３：２００１光ファイバコード付き光コネクタ通則の６．２．４斜めＰＣ研磨の端面形状及び寸法で、球面偏心量として定義されている。球面偏心量は、フェルールの中心と、角度基準面に対しての曲率頂点との距離で定義される。
【００１１】
特に、上述した従来のＭＵ型、ＬＣ型等の斜めＰＣコネクタに用いられる１．２５ｍｍと小径のフェルール用筒状体の研磨では、従来の端面研磨装置の研磨定盤上に設けられた弾性部材の硬度や研磨部材の反りの影響からフェルール用筒状体の先端面の頂点と光ファイバの先端面の中心との距離を所定範囲内に抑えることが困難であるという問題がある。
【００１２】
また、従来の端面研磨装置に用いられる弾性部材の硬度は、５０〜６０Ｈｓであるため、フェルール用筒状体の先端面を研磨部材に押圧する圧力が弱いと凸球面状に形成される研磨面の傾斜角度が安定しないという問題がある。
【００１３】
このため、フェルール用筒状体の先端面を研磨部材に対して高圧力、例えば、約１．７〜２．１Ｎの圧力で押圧しなくてはならないが、複数のフェルール用筒状体の先端面を同時に研磨する場合、例えば、１６本のフェルール用筒状体を同時に研磨する場合には、複数のフェルール用筒状体を保持した治具盤を約２６．７〜３２．９Ｎで押圧しなくてはならず、端面研磨装置に治具盤を高圧力で押圧する能力が求められ、低圧力で押圧する端面研磨装置では研磨を行うことができないという問題がある。
【００１４】
本発明はこのような事情に鑑み、低圧力で先端面を高精度に研磨することができると共に低挿入損失及び高反射減衰量を実現することができる斜めＰＣコネクタのフェルール研磨方法を提供することを課題とする。
【００１５】
【課題を解決するための手段】
本発明の第１の態様は、装置本体に支持されて回転及び揺動する研磨定盤上に載置された弾性部材上の研磨部材に、光ファイバの斜め研磨面同士を対向接続する斜めＰＣコネクタに用いられるフェルールの先端面を押圧して研磨することにより、当該フェルールの先端面を光ファイバ軸に直交する面に対して傾斜した凸面状に形成する斜めＰＣコネクタのフェルール研磨方法において、前記フェルール用筒状体の先端に、前記フェルール用筒状体の外径より外径の小さい先端面を形成する工程と、前記フェルール用筒状体を前記研磨部材の研磨面に対して相対的に傾斜させて当接させ、その軸方向と当該フェルール用筒状体よりも回転中心側の前記研磨面とのなす角度が鈍角となるようにして荒研磨及び中研磨を行う工程と、前記弾性部材を前記荒研磨及び中研磨を行う工程よりも低硬度とし、且つ前記フェルール用筒状体を前記研磨面に対して相対的に傾斜させ、その軸方向と当該フェルール用筒状体よりも回転中心側の前記研磨面とのなす角度が前記荒研磨及び中研磨を行う工程よりも大きな角度となるようにして仕上げ研磨を行う工程とを具備し、前記先端面の外径を０．３ｍｍ〜０．９ｍｍとし、前記荒研磨を行う工程では前記弾性部材の硬度を７０Ｈｓ〜９７Ｈｓの範囲から選択し、前記中研磨を行う工程では前記弾性部材の硬度を７０Ｈｓ〜９７Ｈｓの範囲から選択し、前記仕上げ研磨を行う工程では前記弾性部材の硬度を６０Ｈｓ〜８０Ｈｓの範囲から選択し、前記荒研磨を行う工程では、前記研磨部材の研磨面の傾斜角度を水平面に対して０度〜０．３度とすることにある。
【００１６】
本発明の第２の態様は、装置本体に支持されて回転及び揺動する研磨定盤上に載置された弾性部材上の研磨部材に、光ファイバの斜め研磨面同士を対向接続する斜めＰＣコネクタに用いられるフェルールの先端面を押圧して研磨することにより、当該フェルールの先端面を光ファイバ軸に直交する面に対して傾斜した凸面状に形成する斜めＰＣコネクタのフェルール研磨方法において、前記フェルール用筒状体の先端に、前記フェルール用筒状体の外径より外径の小さい先端面を形成する工程と、前記フェルール用筒状体を前記研磨部材の研磨面に対して相対的に傾斜させて当接させ、その軸方向と当該フェルール用筒状体よりも回転中心側の前記研磨面とのなす角度が鈍角となるようにして荒研磨及び中研磨を行う工程と、前記弾性部材を前記荒研磨及び中研磨を行う工程よりも低硬度とし、且つ前記フェルール用筒状体を前記研磨面に対して相対的に傾斜させ、その軸方向と当該フェルール用筒状体よりも回転中心側の前記研磨面とのなす角度が前記荒研磨及び中研磨を行う工程よりも大きな角度となるようにして仕上げ研磨を行う工程とを具備し、前記先端面の外径を０．３ｍｍ〜０．９ｍｍとし、前記荒研磨を行う工程では前記弾性部材の硬度を７０Ｈｓ〜９７Ｈｓの範囲から選択し、前記中研磨を行う工程では前記弾性部材の硬度を７０Ｈｓ〜９７Ｈｓの範囲から選択し、前記仕上げ研磨を行う工程では前記弾性部材の硬度を６０Ｈｓ〜８０Ｈｓの範囲から選択し、前記中研磨を行う工程では、前記研磨部材の研磨面の傾斜角度を水平面に対して０度〜０．３度とすることにある。
【００１７】
本発明の第３の態様は、装置本体に支持されて回転及び揺動する研磨定盤上に載置された弾性部材上の研磨部材に、光ファイバの斜め研磨面同士を対向接続する斜めＰＣコネクタに用いられるフェルールの先端面を押圧して研磨することにより、当該フェルールの先端面を光ファイバ軸に直交する面に対して傾斜した凸面状に形成する斜めＰＣコネクタのフェルール研磨方法において、前記フェルール用筒状体の先端に、前記フェルール用筒状体の外径より外径の小さい先端面を形成する工程と、前記フェルール用筒状体を前記研磨部材の研磨面に対して相対的に傾斜させて当接させ、その軸方向と当該フェルール用筒状体よりも回転中心側の前記研磨面とのなす角度が鈍角となるようにして荒研磨及び中研磨を行う工程と、前記弾性部材を前記荒研磨及び中研磨を行う工程よりも低硬度とし、且つ前記フェルール用筒状体を前記研磨面に対して相対的に傾斜させ、その軸方向と当該フェルール用筒状体よりも回転中心側の前記研磨面とのなす角度が前記荒研磨及び中研磨を行う工程よりも大きな角度となるようにして仕上げ研磨を行う工程とを具備し、前記先端面の外径を０．３ｍｍ〜０．９ｍｍとし、前記荒研磨を行う工程では前記弾性部材の硬度を７０Ｈｓ〜９７Ｈｓの範囲から選択し、前記中研磨を行う工程では前記弾性部材の硬度を７０Ｈｓ〜９７Ｈｓの範囲から選択し、前記仕上げ研磨を行う工程では前記弾性部材の硬度を６０Ｈｓ〜８０Ｈｓの範囲から選択し、前記仕上げ研磨を行う工程では、前記研磨部材の研磨面の傾斜角度を水平面に対して０．４度〜１．３度とすることにある。
【００１８】
本発明の第４の態様は、装置本体に支持されて回転及び揺動する研磨定盤上に載置された弾性部材上の研磨部材に、光ファイバの斜め研磨面同士を対向接続する斜めＰＣコネクタに用いられるフェルールの先端面を押圧して研磨することにより、当該フェルールの先端面を光ファイバ軸に直交する面に対して傾斜した凸面状に形成する斜めＰＣコネクタのフェルール研磨方法において、
前記フェルール用筒状体の先端に、前記フェルール用筒状体の外径より外径の小さい先端面を形成する工程と、前記フェルール用筒状体を前記研磨部材の研磨面に対して相対的に傾斜させて当接させ、その軸方向と当該フェルール用筒状体よりも回転中心側の前記研磨面とのなす角度が鈍角となるようにして荒研磨及び中研磨を行う工程と、前記弾性部材を前記荒研磨及び中研磨を行う工程よりも低硬度とし、且つ前記フェルール用筒状体を前記研磨面に対して相対的に傾斜させ、その軸方向と当該フェルール用筒状体よりも回転中心側の前記研磨面とのなす角度が前記荒研磨及び中研磨を行う工程よりも大きな角度となるようにして仕上げ研磨を行う工程とを具備し、前記先端面の外径を０．３ｍｍ〜０．９ｍｍとし、前記荒研磨を行う工程では前記弾性部材の硬度を７０Ｈｓ〜９７Ｈｓの範囲から選択し、前記中研磨を行う工程では前記弾性部材の硬度を７０Ｈｓ〜９７Ｈｓの範囲から選択し、前記仕上げ研磨を行う工程では前記弾性部材の硬度を６０Ｈｓ〜８０Ｈｓの範囲から選択し、
前記フェルール用筒状体の先端面を形成する工程では、先端に外径が０．５５ｍｍ〜０．７ｍｍの先端面を形成することにある。
【００１９】
本発明の第５の態様は、装置本体に支持されて回転及び揺動する研磨定盤上に載置された弾性部材上の研磨部材に、光ファイバの斜め研磨面同士を対向接続する斜めＰＣコネクタに用いられるフェルールの先端面を押圧して研磨することにより、当該フェルールの先端面を光ファイバ軸に直交する面に対して傾斜した凸面状に形成する斜めＰＣコネクタのフェルール研磨方法において、前記フェルール用筒状体の先端に、前記フェルール用筒状体の外径より外径の小さい先端面を形成する工程と、前記フェルール用筒状体を前記研磨部材の研磨面に対して相対的に傾斜させて当接させ、その軸方向と当該フェルール用筒状体よりも回転中心側の前記研磨面とのなす角度が鈍角となるようにして荒研磨及び中研磨を行う工程と、前記弾性部材を前記荒研磨及び中研磨を行う工程よりも低硬度とし、且つ前記フェルール用筒状体を前記研磨面に対して相対的に傾斜させ、その軸方向と当該フェルール用筒状体よりも回転中心側の前記研磨面とのなす角度が前記荒研磨及び中研磨を行う工程よりも大きな角度となるようにして仕上げ研磨を行う工程とを具備し、前記先端面の外径を０．３ｍｍ〜０．９ｍｍとし、前記荒研磨を行う工程では前記弾性部材の硬度を７０Ｈｓ〜９７Ｈｓの範囲から選択し、前記中研磨を行う工程では前記弾性部材の硬度を７０Ｈｓ〜９７Ｈｓの範囲から選択し、前記仕上げ研磨を行う工程では前記弾性部材の硬度を６０Ｈｓ〜８０Ｈｓの範囲から選択し、前記フェルール用筒状体の先端面を形成する工程では、当該フェルール用筒状体の先端部に先端面の外径と同等の小径の筒状部を形成することにある。
【００２０】
本発明の第６の態様は、装置本体に支持されて回転及び揺動する研磨定盤上に載置された弾性部材上の研磨部材に、光ファイバの斜め研磨面同士を対向接続する斜めＰＣコネクタに用いられるフェルールの先端面を押圧して研磨することにより、当該フェルールの先端面を光ファイバ軸に直交する面に対して傾斜した凸面状に形成する斜めＰＣコネクタのフェルール研磨方法において、前記フェルール用筒状体の先端に、前記フェルール用筒状体の外径より外径の小さい先端面を形成する工程と、前記フェルール用筒状体を前記研磨部材の研磨面に対して相対的に傾斜させて当接させ、その軸方向と当該フェルール用筒状体よりも回転中心側の前記研磨面とのなす角度が鈍角となるようにして荒研磨及び中研磨を行う工程と、前記弾性部材を前記荒研磨及び中研磨を行う工程よりも低硬度とし、且つ前記フェルール用筒状体を前記研磨面に対して相対的に傾斜させ、その軸方向と当該フェルール用筒状体よりも回転中心側の前記研磨面とのなす角度が前記荒研磨及び中研磨を行う工程よりも大きな角度となるようにして仕上げ研磨を行う工程とを具備し、前記先端面の外径を０．３ｍｍ〜０．９ｍｍとし、前記荒研磨を行う工程では前記弾性部材の硬度を７０Ｈｓ〜９７Ｈｓの範囲から選択し、前記中研磨を行う工程では前記弾性部材の硬度を７０Ｈｓ〜９７Ｈｓの範囲から選択し、前記仕上げ研磨を行う工程では前記弾性部材の硬度を６０Ｈｓ〜８０Ｈｓの範囲から選択し、前記フェルール用筒状体の先端面を形成する工程では、先端に外径が０．３ｍｍ〜０．９ｍｍの先端面を形成することにある。
【００２１】
本発明の第７の態様は、装置本体に支持されて回転及び揺動する研磨定盤上に載置された弾性部材上の研磨部材に、光ファイバの斜め研磨面同士を対向接続する斜めＰＣコネクタに用いられるフェルールの先端面を押圧して研磨することにより、当該フェルールの先端面を光ファイバ軸に直交する面に対して傾斜した凸面状に形成する斜めＰＣコネクタのフェルール研磨方法において、前記フェルール用筒状体の先端に、前記フェルール用筒状体の外径より外径の小さい先端面を形成する工程と、前記フェルール用筒状体を前記研磨部材の研磨面に対して相対的に傾斜させて当接させ、その軸方向と当該フェルール用筒状体よりも回転中心側の前記研磨面とのなす角度が鈍角となるようにして荒研磨及び中研磨を行う工程と、前記弾性部材を前記荒研磨及び中研磨を行う工程よりも低硬度とし、且つ前記フェルール用筒状体を前記研磨面に対して相対的に傾斜させ、その軸方向と当該フェルール用筒状体よりも回転中心側の前記研磨面とのなす角度が前記荒研磨及び中研磨を行う工程よりも大きな角度となるようにして仕上げ研磨を行う工程とを具備し、前記先端面の外径を０．３ｍｍ〜０．９ｍｍとし、前記荒研磨を行う工程では前記弾性部材の硬度を７０Ｈｓ〜９７Ｈｓの範囲から選択し、前記中研磨を行う工程では前記弾性部材の硬度を７０Ｈｓ〜９７Ｈｓの範囲から選択し、前記仕上げ研磨を行う工程では前記弾性部材の硬度を６０Ｈｓ〜８０Ｈｓの範囲から選択し、前記弾性部材の厚みが１ｍｍ〜５ｍｍであることにある。
【００３０】
かかる本発明では、荒研磨及び中研磨時のフェルール用筒状体と研磨部材の研磨面とを当接させる角度に比べて、仕上げ研磨時の角度を大きくして研磨するようにしたため、仕上げ研磨時の研磨始めでは光ファイバの端面を研磨せずにフェルール用筒状体のみを研磨し、研磨が進むにつれ光ファイバの端面を徐々に研磨することができる。これにより、研磨による光ファイバの割れを防止して高精度な研磨を行うことができる。また、所定の硬度の弾性部材を用いて研磨を行うことで、フェルール用筒状体を低圧力で押圧しても安定した傾斜面の先端面を研磨により形成することができる。
【００３１】
【発明の実施の形態】
以下に本発明を実施形態に基づいて詳細に説明する。
【００３２】
（実施形態１）
図１は、本発明方法の実施よって得られる一実施形態のフェルールを示す斜視図、軸方向の平面図及びその断面図である。
【００３３】
図１に示すように、本実施形態のフェルール１０は、外径が１．２５ｍｍで形成されたフェルール用筒状体２０と、フェルール用筒状体２０の一端部に嵌合されたつば部材３０とを具備する。
【００３４】
フェルール用筒状体２０は、円筒形状を有し、その内部には軸方向に貫通して光ファイバ１を挿入保持する光ファイバ挿入孔２１が設けられている。また、この光ファイバ挿入孔２１の後端部には、内径が開口側に向かって漸大するテーパ部２２が設けられている。このようなテーパ部２２を設けることによって、光ファイバ挿入孔２１に光ファイバ１を挿入した際に光ファイバ１の先端がフェルール用筒状体２０の端面に接触することで欠けたり、折れるのを防止することができる。
【００３５】
このようなフェルール用筒状体２０としては、例えば、ジルコニア等のセラミック材料、プラスチック材料及び結晶化ガラス、ホウケイ酸ガラス、石英等のガラス材料、ステンレス、ニッケル、ニッケル合金等の金属材料等からなるものをあげることができる。
【００３６】
また、このフェルール用筒状体２０の先端面２３は、光ファイバ１の先端面と共に光ファイバ軸に直交する面に対して傾斜した凸面状、本実施形態では、凸球面に近似した非球面で形成されている。
【００３７】
この先端面２３は、光ファイバ１近傍の中心領域の曲率半径に対して、傾斜方向突出側の周縁部近傍の曲率半径が大きく且つ傾斜方向他方側の周縁部近傍の曲率半径が小さくなるように形成されている。
【００３８】
また、このような曲率半径は所定の範囲、本実施形態では、５〜１２ｍｍとなるように形成されている。
【００３９】
さらに、フェルール用筒状体２０の凸面状に形成された先端面２３は、光ファイバ１の中心領域から傾斜方向突出側の周縁部までの曲率半径の単位距離当たりの変化量と比較して、傾斜方向他方側の周縁部までの曲率半径の単位距離当たりの変化量が小さくなるように形成されている。
【００４０】
このような凸面状に形成されたフェルール用筒状体２０の先端面２３は、凸面状の先端面２３同士を当接させて対向接続させた際に、例えば、０．２ｄＢ以下の低挿入損失で、且つ６０ｄＢ以上の超高反射減衰量という仕様を実現するため、凸面状に形成された先端面２３の頂点が光ファイバ１の先端面の中心から５０μｍ以下、好ましくは、３０μｍ以下となるように形成されている。
【００４１】
また、このようなフェルール用筒状体２０の先端縁部には、円周方向に亘って光ファイバ軸に対して所定の傾斜角度、本実施形態では、３０度〜４５度の面取り部２４が設けられている。
【００４２】
ここで、本実施形態のフェルール用筒状体２０の先端面２３の測定結果を図２に示す。なお、図２は、フェルール用筒状体の先端面の光ファイバ近傍の中心領域から傾斜方向の距離と曲率半径との関係を示すグラフである。
【００４３】
図２に示すように、本実施形態のフェルール用筒状体２０の先端面２３は、光ファイバ１の先端面の中心を基準として傾斜方向突出側の縁部までの距離及び傾斜方向他方面側の縁部までの距離は０．２５ｍｍとなっている。
【００４４】
この先端面２３の曲率半径は、光ファイバ１近傍の中心領域では、約６．０ｍｍであるのに対して、傾斜方向突出側の周縁部近傍の領域では曲率半径が約７．０ｍｍと中心領域の曲率半径よりも大きくなっている。また、傾斜方向他方側の周縁部近傍の領域では、曲率半径が約５．２ｍｍと中心領域の曲率半径よりも小さくなっている。
【００４５】
また、先端面２３は、傾斜方向突出側及び他方側の縁部までの距離が同等で、傾斜方向突出側の縁部までの曲率半径の変化量が１．０ｍｍなのに対し、傾斜方向他方側の縁部までの曲率半径の変化量が０．８ｍｍと小さいことが分かる。このような先端面２３は、後述するフェルールの端面研磨方法によって容易に且つ高精度に形成することができる。
【００４６】
一方、つば部材３０は、フェルール用筒状体２０の一端部を嵌合させる嵌合孔３１と、光ファイバ１の外周に被覆を施した光ファイバ心線２を挿入保持する光ファイバ心線挿入孔３２と、嵌合孔３１の外周側に円周方向に亘って所定量突出するように設けられたつば部３３とを具備する。
【００４７】
つば部３３は、半径方向の断面が略矩形状となるように形成されており、このつば部３３によって、詳しくは後述するが、フェルール１０が斜めＰＣコネクタのプラグフレームに保持された際に中心軸回りの回転方向の移動が所定角度に規制された状態で保持されるようになっている。
【００４８】
このようなフェルール１０は、例えば、ＭＵ型等の斜めＰＣコネクタに搭載されて光コネクタアダプタ等で対向接続することができる。
【００４９】
ここで、斜めＰＣコネクタについて説明する。図３は、斜めＰＣコネクタの分解斜視図であり、図４は、斜めＰＣコネクタの分解平面図及び組立断面図である。
【００５０】
図示するように、本実施形態の斜めＰＣコネクタ４０は、ＭＵ型の光コネクタアダプタに嵌合するプラグハウジング５０と、プラグハウジング５０内に嵌合すると共に後端部側からフェルール１０が挿入されるプラグフレーム６０と、先端部がプラグフレーム６０の後端部と係合するストップリング７０と、フェルール１０とストップリング７０との間に保持されてフェルール１０を軸方向先端側に向かって付勢する付勢ばね８０とを具備する。
【００５１】
図４に示すように、プラグフレーム６０は、長手方向に亘って貫通したフェルール挿入孔６１を有し、断面が略矩形の例えば、プラスチック材料で形成されている。このフェルール挿入孔６１には、フェルール用筒状体２０の外径よりも若干大きな内径を有し、フェルール用筒状体２０のみが突出可能な突出孔６２が形成された突出用フランジ部６３が設けられている。
【００５２】
また、フェルール挿入孔６１には、突出用フランジ部６３に隣接してつば部３３に係合することによりフェルール１０の中心軸回りの回転方向の移動を所定範囲内に規制する係合孔６４が設けられている。本実施形態では、つば部３３の断面が矩形状に形成されているため、係合孔６４を半径方向の断面がつば部３３よりも若干大きな矩形状とした。
【００５３】
このような係合孔６４は、軸方向に亘って縦及び横の開口幅が所定の幅で設けられており、これによりつば部３３と係合孔６４との間に所定のクリアランスを形成して、フェルール１０の中心軸回りの回転角度が所定範囲となるようにしている。
【００５４】
これは、フェルール用筒状体２０の先端面２３の頂点が光ファイバ１の先端面の中心から５０μｍ以下となるようにしたが、フェルール１０を斜めＰＣコネクタ４０に搭載してフェルール１０の端面同士を対向接続させた際にフェルール１０がプラグフレーム６０に対して中心軸回りに所定角度以上回転すると、フェルール用筒状体２０の先端面２３の頂点が光ファイバ１の先端面の中心から５０μｍ以上ずれた状態と同じ状態となってしまい、低挿入損失及び高反射減衰量を実現できない。このため、所望の挿入損失及び反射減衰量となるフェルール１０の回転角度となるように、プラグフレーム６０の係合孔６４とつば部３３とのクリアランスを適宜設定する必要がある。
【００５５】
また、プラグフレーム６０には、フェルール挿入孔６１と連通して外周に開口する係止孔６５が２つ形成されており、この係止孔６５には、ストップリング７０の先端部に設けられた係止部７５が係止されるようになっている。
【００５６】
また、ストップリング７０は、つば部３３の後端部が挿入可能な軸方向に貫通した貫通孔７１を有する円筒形状で形成された、例えば、ステンレス等の金属やプラスチック材料からなる。
【００５７】
この貫通孔７１は、先端部側に付勢ばね８０を挿入可能な大径部７２と、後端部側につば部材３０の後端部が挿入可能な小径部７３とで構成されており、大径部７２と小径部７３との内径差による段差部７４に付勢ばね８０の一端が当接するようになっている。
【００５８】
なお、付勢ばね８０の他端は、つば部３３の後端部側端面に当接してつば部材３０はストップリング７０に対して軸方向前方側に付勢されるようになっている。
【００５９】
また、ストップリング７０の先端側外周には、ストップリング７０をプラグフレーム６０のフェルール挿入孔６１に挿入した際に、係止孔６５内に突出する係止部７５が設けられている。この係止部７５は、先端に向かって突出量が漸小するテーパ形状で形成されており、係止部７５は、フェルール挿入孔６１内にプラグフレーム６０の後端部を押し広げながら進入して係止孔６５に係止されるようになっている。
【００６０】
このように構成されたプラグフレーム６０にフェルール１０を保持させるには、プラグフレーム６０のフェルール挿入孔６１に光ファイバ１を保持したフェルール１０を挿入し、予め光ファイバ心線２に挿入した付勢ばね８０及びストップリング７０を順次挿入することで、ストップリング７０の係止部７５をプラグフレーム６０の係止孔６５に係止する。これにより、ストップリング７０がプラグフレーム６０に固定される。このとき、フェルール１０のつば部３３の先端面がプラグフレーム６０の突出用フランジ部６３に当接することで、フェルール１０は先端側への移動が規制された状態で突出孔６２から先端部を所定量突き出して軸方向前方側に付勢保持される。
【００６１】
また、このように組み立てられたプラグフレーム６０の外周には、プラグハウジング５０と係合する係合凸部６６が２つ設けられており、これら係合凸部６６がプラグハウジング５０の係合凹部５１と係合することでプラグハウジング５０内にプラグフレーム６０が軸方向の所定範囲に移動自在に保持されて斜めＰＣコネクタ４０が構成されている。
【００６２】
また、このようなフェルール１０は、例えば、フェルール用筒状体２０の先端面を光ファイバ１の軸に垂直な面で形成して斜めＰＣコネクタ４０に搭載し、端面研磨装置によって軸に対して傾斜した凸面状の先端面２３を研磨により形成することができる。もちろん、フェルール１０を単体で研磨することもできる。
【００６３】
ここで、本発明方法を実施するための端面研磨装置の一例について説明する。なお、図５は、端面研磨装置の概略断面図である。
【００６４】
図５に示すように、自転用モータ９１の回転軸には第１自転伝達盤９２の中心部が固結され、この第１自転伝達盤９２には回転中心を支点とする同心円上に複数の第１連結ピン９３が固定されている。そして、この各第１連結ピン９３は対応する各回転伝達盤９４の偏心部に回転自在に連結され、この各回転伝達盤９４には偏心部に第２連結ピン９５が固定されている。各第２連結ピン９５は第２自転伝達盤９６に回転自在に連結されている。
【００６５】
一方、公転用モータ９７の回転軸には駆動歯車９８の中心部が固結され、この駆動歯車９８には従動歯車９９がかみ合っている。この従動歯車９９は公転伝達軸１００の下部外周に固結され、この公転伝達軸１００の上部外周には装置本体１０１の軸受筒部１０２が嵌合している。そして、この公転伝達軸１００には回転中心より所定量偏心した位置に自転用回転軸１０３が回転自在に嵌入し、この自転用回転軸１０３の下端部は第２自転伝達盤９６の中心部に固結されている。
【００６６】
また、自転用回転軸１０３の上端部は結合部材１０４を介して研磨定盤１０５が着脱自在に結合されている。そして、この研磨定盤１０５の上面部には、研磨部材１０６が弾性部材１０７を介して設けられている。
【００６７】
このような研磨定盤１０５は、金属等で形成された円盤形状を有し、弾性部材１０７が設けられる面は、弾性部材１０７上に設けられた研磨部材１０６の研磨面が回転中心に向かって凹状に傾斜するように、回転中心に向かって凹状に傾斜して設けられている。
【００６８】
このような研磨定盤１０５は、詳しくは後述する荒研磨、中研磨及び仕上げ研磨などの各研磨工程によって、弾性部材１０７が設けられる面の傾斜角度が異なる研磨定盤１０５が複数用意されている。
【００６９】
また、研磨定盤１０５上に設けられる弾性部材１０７は、例えば、ゴム、エラストマ、樹脂等からなり、詳しくは後述する荒研磨、中研磨及び仕上げ研磨などの各研磨工程によって、硬度の異なる部材が複数用意されている。
【００７０】
さらに、弾性部材１０７上に設けられた研磨部材１０６としては、例えば、ダイヤモンド、酸化シリコン、酸化セリウム、炭化ケイ素等からなる研磨砥粒を有する研磨シートを挙げることができる。
【００７１】
この研磨シートからなる研磨部材１０６も、荒研磨、中研磨及び仕上げ研磨などの各研磨工程によって、研磨砥粒の粒径が異なる部材が複数用意されている。
【００７２】
一方、装置本体１０１には、支持機構１１０によって複数のフェルール１０又はフェルール１０を保持した斜めＰＣコネクタ４０などが固定された治具盤１２０が支持されている。
【００７３】
ここで、支持機構１１０及び治具盤１２０について詳しく説明する。
【００７４】
図６は、治具盤の斜視図及び側面図であり、図７は、治具盤の上面図であり、図８（ａ）は、図７のＡ−Ａ′断面図、（ｂ）は支持機構１１０と図７のＢ−Ｂ′面の要部断面図である。
【００７５】
図示するように、治具盤１２０は、本実施形態では、フェルール１０を保持した斜めＰＣコネクタ４０を保持するものであり、周縁部に円周方向に亘って複数の凹部１３１が設けられた治具盤本体１３０と、各凹部１３１に対応して設けられた複数の保持部材１４０とを具備する。
【００７６】
治具盤本体１３０は、円盤形状を有し、周縁部近傍に円周方向に亘って複数の凹部１３１が設けられている。この凹部１３１は、フェルール用筒状体２０を保持した斜めＰＣコネクタ４０の先端部を嵌合させて凹部１３１と保持部材１４０との間で斜めＰＣコネクタ４０を保持する。本実施形態では、治具盤１２０が１６本の斜めＰＣコネクタ４０を同時に保持できるように、凹部１３１及び保持部材１４０を１６セット設けたが、治具盤１２０に保持可能な斜めＰＣコネクタ４０の数はこれに限定されず、さらに多数本をセットできるようにしてもよい。
【００７７】
この凹部１３１の底面には、フェルール用筒状体２０の先端部に嵌合する円筒形状を有する筒状体１３２が設けられている。この筒状体１３２は、治具盤本体１３０の厚さ方向に貫通して凹部１３１と保持部材１４０との間で保持された斜めＰＣコネクタ４０のフェルール用筒状体２０の先端部のみを治具盤本体１３０の底面から突出させるようになっている。
【００７８】
また、このような凹部１３１及び筒状体１３２は、詳しくは後述するが、治具盤１２０に斜めＰＣコネクタ４０を保持させた際に、斜めＰＣコネクタ４０の後端部側が治具盤本体１３０の厚さ方向に対して中心から周縁部に向かって傾斜させて保持するような傾斜角度で設けられている。
【００７９】
また、保持部材１４０は、治具盤本体１３０の各凹部１３１に対応して固定された支柱部１４１と、この支柱部１４１の外周に軸方向に移動自在に設けられた保持部１４２と、支柱部１４１の外周面に支柱部１４１と保持部１４２との間で保持された付勢ばね１４３とを具備する。
【００８０】
支柱部１４１は、対応する凹部１３１及び筒状体１３２と同等の傾斜方向及び角度で治具盤本体に固定されている。すなわち、本実施形態では、支柱部の固定された端部とは反対側の端部が治具盤本体の厚さ方向に対して周縁部側に向かって傾斜するように固定されている。
【００８１】
また、保持部１４２は、支柱部１４１の外周に嵌合して支柱部１４１の軸方向に移動自在に設けられたスライド部１４４と、スライド部１４４の一端から延設されて凹部１３１の上部側に突出したアーム部１４５とを有する。
【００８２】
アーム部１４５は、先端部に厚さ方向に貫通すると共に一辺が貫通した矩形の嵌合部１４６が設けられており、この嵌合部１４６が斜めＰＣコネクタ４０の後端部に嵌合するようになっている。
【００８３】
また、支柱部１４１の固定された端部とは反対側の端部側の外周面上には、付勢ばね１４３が設けられている。
【００８４】
この付勢ばね１４３は、一端がスライド部１４４の端部に当接し、他端が支柱部１４１の固定された端部とは反対側の端部に設けられたストッパ部１４７に当接することで、保持部１４２を支柱部１４１の軸方向凹部１３１側へ付勢している。すなわち、凹部１３１側に付勢された保持部１４２は、凹部１３１との間で治具盤本体１３０の底面からフェルール用筒状体２０の先端部を所定量突出させた状態で、傾斜させて保持することができる。
【００８５】
このように、治具盤１２０は、治具盤本体１３０と保持部１４０とによって斜めＰＣコネクタ４０をその後端部側が治具盤本体１３０の中心から周縁部側に向かって所定量傾斜するように保持することができる。
【００８６】
また、治具盤本体１３０の中央部にはボス部１３３が設けられている。このボス部１３３は、支持機構１１０によって治具盤１２０を研磨部材１０６に向かって付勢されると共に支持機構１１０と係合することで治具盤１１０が研磨部材１０６の回転方向に回転するのを防止している。
【００８７】
ここで、このような治具盤１２０を支持する支持機構１１０は、装置本体１０１に研磨定盤１０５側へ移動自在に設けられた支持アーム１１１と、支持アーム１１１の先端側に設けられて治具盤１２０のボス部に固定される押圧部１１２と、支持アーム１１１に設けられて治具盤１２０の回転方向の移動を規制する規制ピン１１３とを具備し、支持アーム１１１は、装置本体１０１に設けられた図示しない押圧手段によって研磨定盤１０５方向に押圧されるようになっている。
【００８８】
すなわち、押圧手段によって押圧された支持アーム１１１は、押圧部１１２の先端に設けられたテーパ部１１２ａが治具盤１２０のボス部１３３のテーパ凹部１３４に当接することで、治具盤１２０を研磨定盤１０５方向に押圧している。
【００８９】
一方、規制ピン１１３は、治具盤１２０のボス部１３３の規制孔１３５に係合することで、治具盤１２０は研磨部材１０６の回転に伴う回転方向の移動が規制されている。
【００９０】
すなわち、治具盤１２０は、支持機構１１０の規制ピン１１３によって回転方向の移動が規制された状態で、押圧部１１２に研磨定盤１０５方向に付勢され、治具盤１２０によって保持された斜めＰＣコネクタ４０のフェルール用筒状体２０の先端面２３を介して研磨部材１０６上に支持される。そして、研磨部材１０６を回転及び揺動することで、フェルール用筒状体２０の先端に光ファイバ軸に垂直な面に対して傾斜した凸面状の先端面２３を形成することができる。
【００９１】
なお、支持アーム１１１を押圧する押圧手段は、特に限定されず、例えば、レバー等により手動で押圧できるものや、駆動モータ等によって自動で押圧できるものなどを挙げることができる。また、押圧手段は、フェルール用筒状体２０の先端面２３を研磨部材１０６に当接させる圧力が把握できるものが好ましく、例えば、ロードセル等の圧力検出手段を設けるのが好ましい。
【００９２】
さらに前記端面研磨装置を用いて斜めＰＣコネクタ４０のフェルール１０の端面を研磨する本発明方法について詳細に説明する。なお、図９は、フェルールの端面研磨方法によるフェルール用筒状体の要部平面図であり、図１０は、フェルールの端面研磨方法によるフェルールと端面研磨装置の要部断面図である。
【００９３】
まず、図９（ａ）に示すフェルール用筒状体２０の状態から、図９（ｂ）に示すように、光ファイバ１を保持したフェルール用筒状体２０の先端に光ファイバ軸に垂直な外径が０．３〜０．９ｍｍの先端面２２３を形成する。
【００９４】
本実施形態では、フェルール用筒状体２０の先端面２２３の縁部を円周方向に亘って光ファイバ軸に対して３０〜４５度傾斜させた面取り部２４を形成することによって所定の外径の先端面２２３を形成した。
【００９５】
この先端面２２３の形成では、後の工程でフェルール用筒状体２０の先端面２２３を研磨して形成した凸面状の先端面２３の頂点と光ファイバ１の端面の中心との距離が５０μｍ以下とするには、研磨前の先端面２２３の外径を０．３〜０．９ｍｍとすることで実現できるが、面取り部２４を３２．５〜４０度の傾斜角度で、研磨前の先端面２２３の外径を０．５５〜０．７ｍｍに形成することで３０μｍ以下とすることができる。
【００９６】
次いで、フェルール用筒状体２０の先端面２２３を研磨することにより、フェルール用筒状体２０に光ファイバ軸に直交する面に対して傾斜した凸面状の先端面２３を形成する。
【００９７】
詳しくは、まず、図１０（ａ）に示すように、フェルール用筒状体２０の先端面２２３を荒研磨して先端面２３ａを形成する。
【００９８】
この荒研磨では、フェルール用筒状体２０を研磨部材１０６ａの研磨面に対して相対的に傾斜させて当接させ、フェルール用筒状体２０の軸方向とフェルール用筒状体２０よりも回転中心側の研磨部材１０６ａの研磨面とのなす角度αが鈍角となるようにして荒研磨を行う。
【００９９】
本実施形態では、上述した端面研磨装置の治具盤１２０が、フェルール用筒状体２０の後端部側を治具盤１２０の移動方向に対して研磨部材１０６ａの回転中心から外側に向かって傾斜させて保持し、研磨部材１０６ａの研磨面が回転中心に向かって凹状となるように傾斜されているため、フェルール用筒状体２０の軸方向とフェルール用筒状体２０よりも回転中心側の研磨部材１０６ａの研磨面とのなす角度αを鈍角とすることができる。
【０１００】
このような状態で治具盤１２０を研磨定盤１０５ａ方向に移動することによって、フェルール用筒状体２０の先端面２２３を研磨部材１０６ａの研磨面に対して相対的に傾斜させて当接させ、研磨定盤１０５ａを回転及び揺動することによって、フェルール用筒状体２０の先端に軸に対して傾斜した凸面状の先端面２３ａを形成することができる。
【０１０１】
治具盤１２０はフェルール用筒状体２０を鉛直方向に対して８度傾斜させて保持し、研磨定盤１０５ａの弾性部材１０７ａの設けられる面、すなわち研磨部材１０６ａの研磨面研磨面の傾斜角度を水平面に対して０〜０．３度とするのが好ましい。なお、本実施形態では、治具盤１２０がフェルール用筒状体２０を鉛直方向に対して８度傾斜させて保持し、研磨定盤１０５ａの弾性部材１０７ａの設けられる面、すなわち研磨部材１０６ａの研磨面を水平方向から０．１２５度傾斜させた。
【０１０２】
また、この荒研磨に用いられる弾性部材１０７ａとしては、７０〜９７Ｈｓの硬度の範囲から選択し、研磨部材１０６ａとしては、研磨砥粒の粒径が８〜１５μｍの研磨シートを用いた。
【０１０３】
このような荒研磨では、弾性部材１０７ａの硬度が比較的高硬度なため、フェルール用筒状体２０を保持した治具盤１２０を比較的小さな圧力で押圧しても、フェルール用筒状体２０の先端に傾斜角度の安定した先端面２３ａを形成することができる。
【０１０４】
本実施形態では、フェルール用筒状体２０に対して０．７４〜１．４７Ｎ／本の圧力で押圧することができ、フェルール用筒状体２０を１６本保持する上述の治具盤１２０では、押圧手段が治具盤１２０を１１．８〜２３．５Ｎの圧力で押圧すればよく、このような比較的低い圧力での押圧は容易に行うことができる。
【０１０５】
次に、図１０（ｂ）に示すように、フェルール用筒状体２０の先端面２３ａを中研磨して先端面２３ｂを形成する。
【０１０６】
この中研磨では、荒研磨時の研磨部材１０６ａよりも研磨砥粒の粒径が小さな研磨シートからなる研磨部材１０６ｂを用いて、フェルール用筒状体２０を荒研磨時と同等の角度で当接させて研磨を行うことにより、フェルール用筒状体２０の先端に先端面２３ｂを形成する。
【０１０７】
なお、研磨部材１０６ｂとしては、研磨砥粒の粒径が０．５μｍ〜４μｍの間が好ましく、ここでは１μｍの研磨シートを用いて、荒研磨時の弾性部材１０７ａを用いた。
【０１０８】
このような中研磨工程では、弾性部材１０７ａは荒研磨と同等で比較的高硬度なため、フェルール用筒状体２０を保持した治具盤１２０を比較的小さな圧力で押圧しても、フェルール用筒状体２０の先端に傾斜角度の安定した先端面２３ｂを形成することができる。
【０１０９】
本実施形態では、フェルール用筒状体２０に対して０．７４〜２．０６Ｎ／本の圧力で押圧することができ、フェルール用筒状体２０を１６本保持する上述の治具盤１２０では、治具盤１２０を１１．８〜３２．９Ｎの圧力で押圧すればよく、このような比較的低い圧力での押圧は容易に行うことができる。
【０１１０】
次に、図１０（ｃ）に示すように、フェルール用筒状体２０の先端面２３ｂを仕上げ研磨して先端面２３を形成する。
【０１１１】
この仕上げ研磨では、中研磨時の弾性部材１０７ａよりも低硬度の弾性部材１０７ｂを用いると共に中研磨時の研磨部材１０６ｂよりも研磨砥粒の粒径の小さな研磨部材１０６ｃを用いて、フェルール用筒状体２０を研磨部材１０６ｃの研磨面に対して相対的に傾斜させて当接させ、フェルール用筒状体２０の軸方向とフェルール用筒状体２０よりも回転中心側の研磨面とのなす角度が荒研磨及び中研磨を行う工程よりも大きな角度となるようにして仕上げ研磨を行う。
【０１１２】
実際には、上述した端面研磨装置の治具盤１２０では、治具盤１２０が保持したフェルール用筒状体２０の傾斜角度を変えられないため、研磨部材１０６ｃの研磨面の傾斜角度を大きくしている。仕上げ研磨を行う工程では、研磨部材１０６ｃの研磨面の傾斜角度は水平面に対して０．４度〜１．３度、好ましくは０．８度から１．０度、より好ましくは０．９度とするのがよい。
【０１１３】
このように研磨部材１０６ｃの傾斜角度を大きくするため、弾性部材１０７ｂが固定される面が研磨定盤１０５ａよりも大きな角度で傾斜した研磨定盤１０５ｂを用いることで、研磨部材１０６ｃの研磨面をより傾斜させて、フェルール用筒状体２０を荒研磨及び中研磨を行う工程よりも大きな角度となるように研磨部材１０６ｃの研磨面に当接させることができる。
【０１１４】
なお、本実施形態では、仕上げ研磨時の弾性部材１０７ｂとしては、硬度が荒研磨及び中研磨を行う際に選択した硬度よりも低硬度となるように、６０〜８０Ｈｓの硬度の範囲から選択すればよい。
【０１１５】
また、仕上げ研磨時の研磨部材１０６ｃとしては、研磨砥粒の粒径が０．０２μｍの研磨シートを用いた。
【０１１６】
このようにフェルール用筒状体２０を研磨部材１０６ｃの研磨面に当接させる角度を荒研磨及び中研磨時よりも大きくすることで、研磨始めは、光ファイバ１の先端面が研磨部材１０６ｃに当接せず、フェルール用筒状体２０のみを研磨する。そして、研磨を進めると、光ファイバ１の先端面を徐々に研磨部材１０６ｃに当接させて研磨することができる。これにより、研磨時の光ファイバ１の割れを防止して、歩留まりのよい研磨を高精度に行うことができる。
【０１１７】
なお、このような仕上げ研磨では、研磨部材１０６ｃの硬度が比較的高硬度なため、フェルール用筒状体２０を保持した治具盤１２０を比較的小さな圧力で押圧しても、フェルール用筒状体２０の先端に傾斜角度の安定した先端面２３を形成することができる。
【０１１８】
具体的には、本実施形態では、フェルール用筒状体２０に対して０．７４〜１．２３Ｎ／本の圧力で押圧することができ、フェルール用筒状体２０を１６本保持する上述の治具盤１２０では、治具盤１２０を１１．８〜１９．６Ｎの圧力で押圧すればよく、このような比較的低い圧力での押圧は容易に行うことができる。
【０１１９】
このようにフェルール用筒状体２０の研磨前の先端面を所定の外径となるように形成すると共に、一連の荒研磨、中研磨及び仕上げ研磨を行うことによって、フェルール用筒状体２０の先端に光ファイバ１の先端面の中心から５０μｍ以下となる頂点の凸面状の先端面２３を高精度に形成することができる。すなわち球面偏心量を５０μｍ以下とすることができる。
【０１２０】
なお、このような斜めＰＣコネクタ４０のフェルール１０の研磨方法は、上述したフェルール１０に限定されず、例えば、従来の形状の斜めＰＣコネクタ用のフェルールにも適用して高精度に研磨することができる。
【０１２１】
以上フェルールについて説明したが、フェルールとつば部材が一体であるフェルールに対しても上述の研磨方法を適応することは可能である。さらに、フェルール用筒状体を研磨し、プリドームフェルールを形成した後、光ファイバをフェルール内に固定し、研磨を行っても良い。
【０１２２】
（実施形態２）
図１１は、フェルールの他の実施形態を示す斜視図、軸方向の平面図及びその断面図である。なお、上述したフェルールの実施形態１で説明した同等の部材には同一の符号を付して重複する説明は省略する。
【０１２３】
図１１に示すように、他の実施例であるフェルール１０Ａは、外径が１．２５ｍｍで形成されたフェルール用筒状体２０Ａと、フェルール用筒状体２０Ａの一端部に嵌合されたつば部材３０とを具備する。
【０１２４】
フェルール用筒状体２０Ａの先端面２３Ａは、上述した実施形態１と同様に、光ファイバ１の先端面と共に光ファイバ軸に直交する面に対して傾斜した凸面状、本実施形態では、凸球面に近似した非球面で形成されている。
【０１２５】
すなわち、先端面２３Ａは、光ファイバ１近傍の中心領域の曲率半径に対して、傾斜方向突出側の周縁部近傍の曲率半径が大きく且つ傾斜方向他方側の周縁部近傍の曲率半径が小さい凸面状で形成であると共にこの光ファイバ１近傍の中心領域の曲率半径及び傾斜方向両側の周縁部近傍の曲率半径は所定の範囲、本実施形態では、５ｍｍ〜１２ｍｍとなるように形成されている。
【０１２６】
さらに、フェルール用筒状体２０Ａの凸面状に形成された先端面２３Ａは、光ファイバ１の中心領域から傾斜方向突出側の周縁部までの曲率半径の単位距離当たりの変化量と比較して、傾斜方向他方側の周縁部までの曲率半径の単位距離当たりの変化量が小さくなるように形成されている。
【０１２７】
また、フェルール用筒状体２０Ａの先端部には、先端面２３Ａと同等の外径を有する小径筒状部２５が設けられている。
【０１２８】
この小径筒状部２５の外径は、凸面状の先端面２３Ａを研磨により形成する前に所定の外径の先端面２３Ａを形成するために設けられたものであり、本実施形態では、フェルール用筒状体２０Ａの研磨前の垂直な先端面の外径を０．３〜０．９ｍｍとするため、小径筒状部の外径も０．３〜０．９ｍｍとなっている。
【０１２９】
また、フェルール用筒状体２０Ａの小径筒状部２５との外径差による段差が形成された縁部には、面取り部２４Ａが形成されている。
【０１３０】
このようなフェルール用筒状体２０Ａは、予め小径筒状部２５を形成した後に上述した実施形態１と同様に研磨することによって、容易に且つ高精度に形成することができる。
【０１３１】
なお、フェルール用筒状体２０Ａの凸面状の先端面２３Ａの頂点と光ファイバ１の先端面の中心との距離が５０μｍ以下となるようにするには、研磨前の先端面及び小径筒状部２５の外径を０．３〜０．９ｍｍとすることで実現できるが、小径筒状部２５及び先端面２３Ａの外径を０．５５〜０．７ｍｍに形成することで３０μｍ以下とすることができる。なお、小径筒状部２５は、例えば、研削等によって形成することができる。
【０１３２】
（他の実施形態）
以上、本発明方法による実施形態１及び２を説明したが、本発明の斜めＰＣコネクタのフェルールの研磨方法は、上述したものに限定されるものではない。
【０１３３】
例えば、上述した実施形態１では、研磨定盤１０５、１０５ａ、１０５ｂを回転中心に向かって凹状に傾斜させ、治具盤１２０に斜めＰＣコネクタ４０の後端部側が治具盤本体１３０の厚さ方向に対して中心から周縁部に向かって傾斜、すなわち逆ハの字状に保持するような傾斜角度で設けることで、フェルール用筒状体の先端面が光ファイバ近傍の中心領域の曲率半径に対して、傾斜方向突出側の周縁部近傍の曲率半径が大きく、傾斜方向他方側の周縁部近傍の曲率半径が小さい凸面状としたが、研磨定盤を回転中心に向かって凸状に傾斜させ、治具盤は斜めＰＣコネクタの後端部側が治具盤本体の厚さ方向に対して中心方向に向かって傾斜、すなわちハの字状に保持するような傾斜角度で設けるようにしても同様の端面研磨が可能である。
【０１３４】
また例えば、上述した実施形態１では、端面研磨装置の治具盤１２０が、斜めＰＣコネクタ４０を傾斜させて保持し、研磨部材１０６ａ〜１０６ｃの研磨面を荒研磨及び中研磨と仕上げ研磨とで傾斜角度を変えることによって、各研磨工程時の角度の調整を行うようにしたが、これに限定されず、例えば、研磨部材の研磨面を各研磨工程で傾斜角度を変えず、フェルール用筒状体を保持した治具盤が、フェルール用筒状体の傾斜角度を各研磨工程で変えられるような構造としてもよい。
【０１３５】
このように、各研磨工程でフェルール用筒状体の軸方向と研磨部材の研磨面とのなす角度を調整できれば、端面研磨装置は上述したものに限定されるものではない。
【０１３６】
また、上述した実施形態１及び２では、ＭＵ型斜めＰＣコネクタ用のフェルールを例示したが、ＬＣ型等の斜めＰＣコネクタ用のフェルールとしてもよい。
【０１３７】
さらに、上述した実施形態１及び２では、フェルール用筒状体の外径を１．２５ｍｍとしたが、これに限定されず、フェルール用筒状体の外径が２．５ｍｍのＳＣ型、ＦＣ型等の斜めＰＣコネクタ用のフェルールとしてもよい。
【０１３８】
このようなフェルールであっても、上述した実施形態１及び２と同様に研磨前の先端面の外径や、各研磨工程の傾斜角度の調整及び弾性部材の硬度などにより、容易に且つ高精度に傾斜した凸面状の先端面を形成することができる。
【０１３９】
【発明の効果】
以上説明したように、本発明では、荒研磨及び中研磨時のフェルール用筒状体と研磨部材の研磨面とを当接させる角度に比べて、仕上げ研磨時の角度を大きくして研磨するようにしたため、光ファイバの割れを防止して高精度な研磨を行うことができる。また、所定の硬度の弾性部材を用いて研磨を行うことで、フェルール用筒状体を低圧力で押圧しても安定した研磨を行うことができる。これにより、低挿入損失及び高反射減衰量の斜めＰＣコネクタのフェルールを実現することができる。
【図面の簡単な説明】
【図１】本発明の実施形態１に係るフェルールの斜視図、軸方向の平面図及びその断面図である。
【図２】本発明の実施形態１に係るフェルール用筒状体の先端面の光ファイバ近傍の中心領域から傾斜方向の距離と曲率半径との関係を示すグラフである。
【図３】本発明の実施形態１に係る斜めＰＣコネクタの分解斜視図である。
【図４】本発明の実施形態１に係る斜めＰＣコネクタの分解平面図及び組立断面図である。
【図５】本発明の実施形態１に係る端面研磨装置の概略断面図である。
【図６】本発明の実施形態１に係る治具盤の斜視図及び側面図である。
【図７】本発明の実施形態１に係る治具盤の上面図である。
【図８】本発明の実施形態１に係る治具盤の断面図であり、（ａ）は支持機構と図７のＡ−Ａ′断面図、（ｂ）は図７のＢ−Ｂ′断面図である。
【図９】本発明の実施形態１に係るフェルールの端面研磨方法を示すフェルール用筒状体の要部平面図である。
【図１０】本発明の実施形態１に係るフェルールの端面研磨方法を示すフェルール及び端面研磨装置の要部断面図である。
【図１１】本発明の実施形態２に係るフェルールの斜視図、軸方向の平面図及びその断面図である。
【図１２】従来技術に係るフェルールの斜視図、軸方向の平面図及び端面方向の平面図である。
【符号の説明】
１０、１０Ａフェルール
２０、２０Ａフェルール用筒状体
２３、２３ａ、２３ｂ、２３Ａ先端面
２４、２４Ａ面取り部
２５小径筒状部
３０つば部材
３３つば部
４０斜めＰＣコネクタ
５０プラグハウジング
６０プラグフレーム
７０ストップリング
８０付勢ばね
１０５、１０５ａ、１０５ｂ研磨定盤
１０６、１０６ａ、１０６ｂ、１０６ｃ研磨部材
１０７、１０７ａ、１０７ｂ弾性部材
１１０支持機構
１２０治具盤[0001]
BACKGROUND OF THE INVENTION
  INDUSTRIAL APPLICABILITY The present invention is used for an oblique PC connector that connects oblique polished end faces of optical fibers.Ferrule polishing methodAbout.
[0002]
[Prior art]
  In an optical connector used in optical communication or the like, the end face of the optical fiber held by the ferrule is made perpendicular to the axis of the optical fiber together with the ferrule end face for the purpose of reducing connection loss at the connector connecting portion and reducing reflected return light. On the other hand, an “oblique PC (Physical Contact) connector” that is slanted and polished to a convex spherical surface is used.
[0003]
  Here, a ferrule used for a conventional MU-type oblique PC connector will be described.
[0004]
  FIG. 12 is a perspective view and a plan view of a ferrule according to the prior art.
[0005]
  As shown in FIG. 12, the ferrule 310 used for the oblique PC connector has a cylindrical body 320 for ferrules having a cylindrical shape provided in a convex spherical shape in which a tip surface 323 is inclined with respect to a surface orthogonal to the axis; The collar member 330 includes a collar member 330 fitted to the rear end portion of the ferrule tubular body 320. The collar member 330 includes a collar portion projecting radially in the circumferential direction on the outer periphery on the ferrule tubular body 310 side. 333 is provided. The collar portion 333 is formed in a substantially rectangular shape in cross section in the radial direction, and has the same shape as the collar portion 333 provided in the plug frame when the ferrule 310 is held by the plug frame of the oblique PC connector. The movement of the ferrule 310 around the central axis is restricted by engaging with the formed engagement hole.
[0006]
  Such a ferrule 310 is held in a plug frame and is connected to the front end surfaces 323 of the ferrule tubular body 320 by an optical connector adapter or the like, thereby achieving low insertion loss and high reflection attenuation. A quantity of optical connections can be made.
[0007]
  Such a ferrule 310 for an oblique PC connector can be formed into a convex spherical shape whose tip surface 323 is inclined with respect to a surface perpendicular to the optical fiber axis by an end surface polishing apparatus.
[0008]
  This end surface polishing apparatus is configured such that the rear end side of the diagonal PC connector on the jig plate is in a direction perpendicular to the polishing surface of the polishing member, on the elastic member placed on the rotating and swinging polishing surface plate. On the other hand, it can be formed by holding the end surface of the ferrule 310 of the oblique PC connector against the polishing member and polishing it while holding it inclined toward the rotation center of the polishing surface plate (for example, Patent Document 1). reference.).
[0009]
[Patent Document 1]
  Japanese Patent Laid-Open No. 8-112745 (page 3, FIG. 1)
[0010]
[Problems to be solved by the invention]
  However, the ferrule for the oblique PC connector formed in this way has a convex spherical tip end surface of the ferrule cylindrical body in order to reduce insertion loss and increase return loss when facing each other. There is a problem that it is difficult to form the apex at a position within a predetermined range from the central axis of the end face of the optical fiber, for example, 50 μm or less. Here, the deviation from the center of the ferrule at the apex of the end face of the ferrule for the oblique PC connector is the end face shape and dimensions of 62.4 oblique PC polishing in the optical connector general rule of JIS C 5963: 2001 optical fiber cord. It is defined as the amount of spherical eccentricity. The spherical eccentricity is defined by the distance between the center of the ferrule and the vertex of curvature with respect to the angle reference plane.
[0011]
  In particular, in polishing a cylindrical body for a ferrule having a small diameter of 1.25 mm used for the above-mentioned conventional MU type, LC type and other oblique PC connectors, an elastic member provided on a polishing surface plate of a conventional end surface polishing apparatus There is a problem that it is difficult to keep the distance between the apex of the end surface of the ferrule tubular body and the center of the end surface of the optical fiber within a predetermined range due to the influence of the hardness and the warp of the polishing member.
[0012]
  Moreover, since the hardness of the elastic member used for the conventional end surface polishing apparatus is 50 to 60 Hs, the polishing surface is formed into a convex spherical shape when the pressure for pressing the tip surface of the ferrule tubular body against the polishing member is weak. There is a problem that the inclination angle of the is not stable.
[0013]
  For this reason, the tip surface of the ferrule tubular body must be pressed against the polishing member with a high pressure, for example, a pressure of about 1.7 to 2.1 N. When simultaneously polishing the surface, for example, when simultaneously polishing 16 ferrule cylinders, press the jig board holding a plurality of ferrule cylinders at about 26.7-32.9 N. There is a problem that the end face polishing apparatus is required to be capable of pressing the jig board with high pressure, and the end face polishing apparatus that presses with low pressure cannot perform polishing.
[0014]
  In view of such circumstances, the present invention is an oblique PC connector capable of polishing the tip surface with high accuracy at low pressure and realizing low insertion loss and high return loss.Ferrule polishing methodIt is an issue to provide.
[0015]
[Means for Solving the Problems]
  The first aspect of the present invention is an oblique PC for connecting obliquely polished surfaces of optical fibers to a polishing member on an elastic member mounted on a polishing surface plate supported and rotated by an apparatus body. In the ferrule polishing method for an oblique PC connector, the front surface of the ferrule used in the connector is pressed and polished to form a convex surface inclined with respect to a surface perpendicular to the optical fiber axis. Forming a tip surface having an outer diameter smaller than the outer diameter of the ferrule tubular body at the distal end of the ferrule tubular body, and the ferrule tubular body relative to the polishing surface of the polishing member. Inclining and abutting, and performing rough polishing and intermediate polishing so that an angle formed between the axial direction and the polishing surface closer to the rotation center than the ferrule tubular body is obtuse, and the elastic member The The hardness is lower than the step of performing rough polishing and intermediate polishing, and the ferrule tubular body is inclined relative to the polishing surface, and its axial direction and the rotation center side of the ferrule tubular body And finishing polishing such that the angle formed with the polishing surface is larger than that of the rough polishing and intermediate polishing steps, and the outer diameter of the tip surface is 0.3 mm to 0.00 mm. The hardness of the elastic member is selected from the range of 70Hs to 97Hs in the step of performing rough polishing, and the hardness of the elastic member is selected from the range of 70Hs to 97Hs in the step of performing intermediate polishing. In the step of performing, the hardness of the elastic member is selected from the range of 60Hs to 80HsIn the rough polishing step, the inclination angle of the polishing surface of the polishing member is 0 degree to 0.3 degree with respect to the horizontal plane.There is to do.
[0016]
  The second aspect of the present invention is:The tip end surface of a ferrule used for an oblique PC connector that connects the oblique polished surfaces of optical fibers to each other on a polishing member on an elastic member that is mounted on a polishing surface plate supported and rotated by an apparatus main body. In the ferrule polishing method of the oblique PC connector, in which the tip surface of the ferrule is formed into a convex surface inclined with respect to the surface orthogonal to the optical fiber axis by pressing and polishing, at the tip of the ferrule tubular body, A step of forming a tip surface having an outer diameter smaller than the outer diameter of the ferrule cylindrical body, and the ferrule cylindrical body is brought into contact with the polishing surface of the polishing member while being inclined relative to the polishing surface. Performing rough polishing and intermediate polishing so that the angle formed between the direction and the polishing surface closer to the rotation center than the ferrule tubular body is an obtuse angle; and the rough polishing and intermediate polishing of the elastic member. The ferrule cylindrical body is inclined relative to the polishing surface, and the axial direction of the ferrule cylindrical body is formed between the polishing surface on the rotation center side of the ferrule cylindrical body. And a step of performing final polishing such that the angle is larger than that of the rough polishing and intermediate polishing steps, the outer diameter of the tip surface is set to 0.3 mm to 0.9 mm, and the rough polishing is performed. In the step of performing, the hardness of the elastic member is selected from the range of 70Hs to 97Hs, in the step of performing the intermediate polishing, the hardness of the elastic member is selected from the range of 70Hs to 97Hs, and in the step of performing the final polishing, the elastic member is selected. Is selected from the range of 60Hs to 80Hs, and in the step of performing the intermediate polishing, the inclination angle of the polishing surface of the polishing member is set to 0 degree to 0.3 degree with respect to the horizontal plane.There is.
[0017]
  The third aspect of the present invention is:The tip end surface of a ferrule used for an oblique PC connector that connects the oblique polished surfaces of optical fibers to each other on a polishing member on an elastic member that is mounted on a polishing surface plate supported and rotated by an apparatus main body. In the ferrule polishing method of the oblique PC connector, in which the tip surface of the ferrule is formed into a convex surface inclined with respect to the surface orthogonal to the optical fiber axis by pressing and polishing, at the tip of the ferrule tubular body, A step of forming a tip surface having an outer diameter smaller than the outer diameter of the ferrule cylindrical body, and the ferrule cylindrical body is brought into contact with the polishing surface of the polishing member while being inclined relative to the polishing surface. Performing rough polishing and intermediate polishing so that the angle formed between the direction and the polishing surface closer to the rotation center than the ferrule tubular body is an obtuse angle; and the rough polishing and intermediate polishing of the elastic member. The ferrule cylindrical body is inclined relative to the polishing surface, and the axial direction of the ferrule cylindrical body is formed between the polishing surface on the rotation center side of the ferrule cylindrical body. And a step of performing final polishing such that the angle is larger than that of the rough polishing and intermediate polishing steps, the outer diameter of the tip surface is set to 0.3 mm to 0.9 mm, and the rough polishing is performed. In the step of performing, the hardness of the elastic member is selected from the range of 70Hs to 97Hs, in the step of performing the intermediate polishing, the hardness of the elastic member is selected from the range of 70Hs to 97Hs, and in the step of performing the final polishing, the elastic member is selected. Is selected from the range of 60Hs to 80Hs, and in the step of performing the final polishing, the inclination angle of the polishing surface of the polishing member is 0.4 to 1.3 degrees with respect to the horizontal plane.There is to do.
[0018]
  The fourth aspect of the present invention is:The tip end surface of a ferrule used for an oblique PC connector that connects the oblique polished surfaces of optical fibers to each other on a polishing member on an elastic member that is mounted on a polishing surface plate supported and rotated by an apparatus main body. In the ferrule polishing method of an oblique PC connector that forms a convex surface inclined with respect to a surface orthogonal to the optical fiber axis by pressing and polishing the ferrule tip surface,
Forming a tip surface having an outer diameter smaller than the outer diameter of the ferrule tubular body at the tip of the ferrule tubular body, and the ferrule tubular body relative to the polishing surface of the polishing member. A step of performing rough polishing and intermediate polishing so that an angle formed between the axial direction and the polishing surface closer to the rotation center than the ferrule tubular body is an obtuse angle, and the elasticity The member has a lower hardness than the step of rough polishing and intermediate polishing, and the ferrule tubular body is inclined relative to the polishing surface, and its axial direction and the ferrule tubular body rotate. And a step of performing final polishing so that the angle formed with the polishing surface on the center side is larger than the step of performing the rough polishing and intermediate polishing, and the outer diameter of the tip surface is 0.3 mm to 0.9mm and the rough polishing process Then, the hardness of the elastic member is selected from the range of 70Hs to 97Hs, the hardness of the elastic member is selected from the range of 70Hs to 97Hs in the intermediate polishing step, and the hardness of the elastic member in the step of finishing polishing. Is selected from the range of 60Hs to 80Hs,
In the step of forming the tip surface of the ferrule tubular body, a tip surface having an outer diameter of 0.55 mm to 0.7 mm is formed at the tip.There is to do.
[0019]
  According to a fifth aspect of the present invention,The tip end surface of a ferrule used for an oblique PC connector that connects the oblique polished surfaces of optical fibers to each other on a polishing member on an elastic member that is mounted on a polishing surface plate supported and rotated by an apparatus main body. In the ferrule polishing method of the oblique PC connector, in which the tip surface of the ferrule is formed into a convex surface inclined with respect to the surface orthogonal to the optical fiber axis by pressing and polishing, at the tip of the ferrule tubular body, A step of forming a tip surface having an outer diameter smaller than the outer diameter of the ferrule cylindrical body, and the ferrule cylindrical body is brought into contact with the polishing surface of the polishing member while being inclined relative to the polishing surface. Performing rough polishing and intermediate polishing so that the angle formed between the direction and the polishing surface closer to the rotation center than the ferrule tubular body is an obtuse angle; and the rough polishing and intermediate polishing of the elastic member. The ferrule cylindrical body is inclined relative to the polishing surface, and the axial direction of the ferrule cylindrical body is formed between the polishing surface on the rotation center side of the ferrule cylindrical body. And a step of performing final polishing such that the angle is larger than that of the rough polishing and intermediate polishing steps, the outer diameter of the tip surface is set to 0.3 mm to 0.9 mm, and the rough polishing is performed. In the step of performing, the hardness of the elastic member is selected from the range of 70Hs to 97Hs, in the step of performing the intermediate polishing, the hardness of the elastic member is selected from the range of 70Hs to 97Hs, and in the step of performing the final polishing, the elastic member is selected. Is selected from the range of 60Hs to 80Hs, and in the step of forming the distal end surface of the ferrule tubular body, a tubular portion having a small diameter equivalent to the outer diameter of the distal end surface is formed at the distal end portion of the ferrule tubular body The FormationThere is to do.
[0020]
  The sixth aspect of the present invention is:The tip end surface of a ferrule used for an oblique PC connector that connects the oblique polished surfaces of optical fibers to each other on a polishing member on an elastic member that is mounted on a polishing surface plate supported and rotated by an apparatus main body. In the ferrule polishing method of the oblique PC connector, in which the tip surface of the ferrule is formed into a convex surface inclined with respect to the surface orthogonal to the optical fiber axis by pressing and polishing, at the tip of the ferrule tubular body, A step of forming a tip surface having an outer diameter smaller than the outer diameter of the ferrule cylindrical body, and the ferrule cylindrical body is brought into contact with the polishing surface of the polishing member while being inclined relative to the polishing surface. Performing rough polishing and intermediate polishing so that the angle formed between the direction and the polishing surface closer to the rotation center than the ferrule tubular body is an obtuse angle; and the rough polishing and intermediate polishing of the elastic member. The ferrule cylindrical body is inclined relative to the polishing surface, and the axial direction of the ferrule cylindrical body is formed between the polishing surface on the rotation center side of the ferrule cylindrical body. And a step of performing final polishing such that the angle is larger than that of the rough polishing and intermediate polishing steps, the outer diameter of the tip surface is set to 0.3 mm to 0.9 mm, and the rough polishing is performed. In the step of performing, the hardness of the elastic member is selected from the range of 70Hs to 97Hs, in the step of performing the intermediate polishing, the hardness of the elastic member is selected from the range of 70Hs to 97Hs, and in the step of performing the final polishing, the elastic member is selected. Is selected from the range of 60Hs to 80Hs, and in the step of forming the tip surface of the ferrule tubular body, a tip surface having an outer diameter of 0.3 mm to 0.9 mm is formed at the tip.There is to do.
[0021]
  The seventh aspect of the present invention isThe tip end surface of a ferrule used for an oblique PC connector that connects the oblique polished surfaces of optical fibers to each other on a polishing member on an elastic member that is mounted on a polishing surface plate supported and rotated by an apparatus main body. In the ferrule polishing method of the oblique PC connector, in which the tip surface of the ferrule is formed into a convex surface inclined with respect to the surface orthogonal to the optical fiber axis by pressing and polishing, at the tip of the ferrule tubular body, A step of forming a tip surface having an outer diameter smaller than the outer diameter of the ferrule cylindrical body, and the ferrule cylindrical body is brought into contact with the polishing surface of the polishing member while being inclined relative to the polishing surface. Performing rough polishing and intermediate polishing so that the angle formed between the direction and the polishing surface closer to the rotation center than the ferrule tubular body is an obtuse angle; and the rough polishing and intermediate polishing of the elastic member. The ferrule cylindrical body is inclined relative to the polishing surface, and the axial direction of the ferrule cylindrical body is formed between the polishing surface on the rotation center side of the ferrule cylindrical body. And a step of performing final polishing such that the angle is larger than that of the rough polishing and intermediate polishing steps, the outer diameter of the tip surface is set to 0.3 mm to 0.9 mm, and the rough polishing is performed. In the step of performing, the hardness of the elastic member is selected from the range of 70Hs to 97Hs, in the step of performing the intermediate polishing, the hardness of the elastic member is selected from the range of 70Hs to 97Hs, and in the step of performing the final polishing, the elastic member is selected. The hardness of the elastic member is selected from the range of 60Hs to 80Hs, and the thickness of the elastic member is 1 mm to 5 mmThere is.
[0030]
In the present invention, since the angle at the time of final polishing is larger than the angle at which the cylindrical body for ferrule and the polishing surface of the polishing member abut at the time of rough polishing and intermediate polishing, polishing is performed. At the beginning of polishing, it is possible to polish only the ferrule tube without polishing the end face of the optical fiber, and gradually polish the end face of the optical fiber as the polishing proceeds. Thereby, it is possible to prevent the optical fiber from being broken by polishing and perform highly accurate polishing. Further, by polishing using an elastic member having a predetermined hardness, a stable tip surface of the inclined surface can be formed by polishing even when the ferrule tubular body is pressed with a low pressure.
[0031]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on embodiments.
[0032]
(Embodiment 1)
FIG.1 shows a ferrule of an embodiment obtained by carrying out the method of the present invention.It is a perspective view, an axial plan view, and a cross-sectional view thereof.
[0033]
As shown in FIG. 1, the ferrule 10 of this embodiment includes a ferrule tubular body 20 having an outer diameter of 1.25 mm, and a collar member 30 fitted to one end of the ferrule tubular body 20. It comprises.
[0034]
The ferrule cylindrical body 20 has a cylindrical shape, and an optical fiber insertion hole 21 is provided in the inside thereof so as to penetrate the axial direction and insert and hold the optical fiber 1. A tapered portion 22 having an inner diameter that gradually increases toward the opening side is provided at the rear end portion of the optical fiber insertion hole 21. By providing such a tapered portion 22, when the optical fiber 1 is inserted into the optical fiber insertion hole 21, the tip of the optical fiber 1 comes into contact with the end surface of the ferrule tubular body 20 so that it can be cut or broken. Can be prevented.
[0035]
Examples of the ferrule cylindrical body 20 include ceramic materials such as zirconia, plastic materials and crystallized glass, glass materials such as borosilicate glass and quartz, and metal materials such as stainless steel, nickel, and nickel alloys. I can give you something.
[0036]
Further, the distal end surface 23 of the ferrule tubular body 20 is a convex surface inclined with respect to a surface orthogonal to the optical fiber axis together with the distal end surface of the optical fiber 1, in this embodiment, an aspherical surface approximated to a convex spherical surface. Is formed.
[0037]
The distal end face 23 has a larger radius of curvature in the vicinity of the peripheral edge on the protruding side in the tilt direction and a smaller radius of curvature in the vicinity of the peripheral edge on the other side in the inclined direction than the radius of curvature of the central region in the vicinity of the optical fiber 1. Is formed.
[0038]
Moreover, such a curvature radius is formed so that it may become a predetermined range, and 5-12 mm in this embodiment.
[0039]
Furthermore, the tip surface 23 formed in the convex shape of the ferrule tubular body 20 is compared with the amount of change per unit distance of the radius of curvature from the central region of the optical fiber 1 to the peripheral edge on the inclined direction protruding side, It is formed so that the amount of change per unit distance of the radius of curvature up to the peripheral edge on the other side in the tilt direction is small.
[0040]
The tip surface 23 of the ferrule tubular body 20 formed in such a convex shape is, for example, a low insertion loss of 0.2 dB or less when the convex tip surfaces 23 are brought into contact with each other to be opposed to each other. In order to realize the specification of ultrahigh reflection attenuation of 60 dB or more, the apex of the convex end surface 23 is 50 μm or less from the center of the end surface of the optical fiber 1, preferably 30 μm or less. Is formed.
[0041]
In addition, a chamfered portion 24 having a predetermined inclination angle with respect to the optical fiber axis in the circumferential direction, in this embodiment, 30 to 45 degrees is provided at the distal end edge of the ferrule tubular body 20. Is provided.
[0042]
Here, the measurement result of the front end surface 23 of the cylindrical body 20 for ferrule of this embodiment is shown in FIG. FIG. 2 is a graph showing the relationship between the distance in the inclination direction from the central region in the vicinity of the optical fiber on the tip surface of the ferrule tubular body and the radius of curvature.
[0043]
As shown in FIG. 2, the distal end surface 23 of the ferrule tubular body 20 according to the present embodiment has a distance to the edge on the tilt direction protruding side with respect to the center of the distal end surface of the optical fiber 1 and the other surface side in the tilt direction. The distance to the edge is 0.25 mm.
[0044]
The radius of curvature of the distal end surface 23 is about 6.0 mm in the central region near the optical fiber 1, whereas the radius of curvature is about 7.0 mm in the region near the peripheral edge on the inclined direction protruding side. It is larger than the radius of curvature. Moreover, in the area | region of the peripheral part of the other side of an inclination direction, the curvature radius is about 5.2 mm and is smaller than the curvature radius of a center area | region.
[0045]
Further, the tip surface 23 has the same distance to the edge on the inclined direction protruding side and the edge on the other side, and the amount of change in the radius of curvature to the edge on the protruding side in the inclined direction is 1.0 mm, whereas It can be seen that the amount of change in the radius of curvature up to the edge is as small as 0.8 mm. Such a front end face 23 can be easily and highly accurately formed by a ferrule end face polishing method described later.
[0046]
On the other hand, the collar member 30 has a fitting hole 31 for fitting one end of the ferrule tubular body 20 and an optical fiber core insertion for inserting and holding the optical fiber core 2 coated on the outer periphery of the optical fiber 1. The hole 32 and the collar part 33 provided in the outer peripheral side of the fitting hole 31 so that a predetermined amount may be protruded over the circumferential direction are comprised.
[0047]
The collar portion 33 is formed so that the cross section in the radial direction is substantially rectangular, and the collar portion 33 will be described later in detail, but the center when the ferrule 10 is held by the plug frame of the oblique PC connector. The movement in the rotational direction around the axis is held in a state where the movement is restricted to a predetermined angle.
[0048]
Such a ferrule 10 can be mounted on an oblique PC connector such as an MU type and can be connected to each other with an optical connector adapter or the like.
[0049]
Here, the oblique PC connector will be described. FIG. 3 is an exploded perspective view of the oblique PC connector, and FIG. 4 is an exploded plan view and an assembled sectional view of the oblique PC connector.
[0050]
As shown in the figure, the oblique PC connector 40 of the present embodiment is fitted with a plug housing 50 that fits into the MU type optical connector adapter, and the ferrule 10 is inserted from the rear end side while fitting into the plug housing 50. The plug frame 60, the stop ring 70 whose front end is engaged with the rear end of the plug frame 60, and held between the ferrule 10 and the stop ring 70 to urge the ferrule 10 toward the front end in the axial direction. And an urging spring 80.
[0051]
As shown in FIG. 4, the plug frame 60 has a ferrule insertion hole 61 that penetrates in the longitudinal direction, and is formed of, for example, a plastic material having a substantially rectangular cross section. The ferrule insertion hole 61 has a projecting flange portion 63 having an inner diameter slightly larger than the outer diameter of the ferrule tubular body 20 and having a projecting hole 62 into which only the ferrule tubular body 20 can project. Is provided.
[0052]
The ferrule insertion hole 61 has an engagement hole 64 that restricts movement of the ferrule 10 around the central axis in a predetermined range by engaging with the flange portion 33 adjacent to the projecting flange portion 63. Is provided. In the present embodiment, since the cross section of the collar portion 33 is formed in a rectangular shape, the engagement hole 64 has a rectangular shape whose radial cross section is slightly larger than the collar portion 33.
[0053]
Such an engagement hole 64 is provided with a predetermined vertical and horizontal opening width in the axial direction, thereby forming a predetermined clearance between the flange portion 33 and the engagement hole 64. Thus, the rotation angle around the central axis of the ferrule 10 is set within a predetermined range.
[0054]
This is because the apex of the distal end surface 23 of the ferrule tubular body 20 is 50 μm or less from the center of the distal end surface of the optical fiber 1, but the ferrule 10 is mounted on the oblique PC connector 40 and the end surfaces of the ferrule 10 are When the ferrule 10 is rotated by a predetermined angle or more around the central axis with respect to the plug frame 60 when the two are connected to each other, the apex of the tip surface 23 of the ferrule tubular body 20 is 50 μm or more from the center of the tip surface of the optical fiber 1. It becomes the same state as the shifted state, and low insertion loss and high return loss cannot be realized. For this reason, it is necessary to appropriately set the clearance between the engagement hole 64 of the plug frame 60 and the collar portion 33 so that the rotation angle of the ferrule 10 becomes a desired insertion loss and return loss.
[0055]
The plug frame 60 is formed with two locking holes 65 that communicate with the ferrule insertion hole 61 and open to the outer periphery. The locking hole 65 is provided at the tip of the stop ring 70. The locking part 75 is locked.
[0056]
The stop ring 70 is made of a metal such as stainless steel or a plastic material, for example, having a through hole 71 that penetrates in the axial direction in which the rear end portion of the collar portion 33 can be inserted.
[0057]
The through-hole 71 is composed of a large-diameter portion 72 into which the biasing spring 80 can be inserted on the front end side, and a small-diameter portion 73 into which the rear end portion of the collar member 30 can be inserted on the rear end side. One end of the urging spring 80 abuts on the stepped portion 74 due to the inner diameter difference between the large diameter portion 72 and the small diameter portion 73.
[0058]
The other end of the urging spring 80 abuts on the end surface of the collar portion 33 on the rear end portion side, so that the collar member 30 is urged axially forward with respect to the stop ring 70.
[0059]
Further, a locking portion 75 that protrudes into the locking hole 65 when the stop ring 70 is inserted into the ferrule insertion hole 61 of the plug frame 60 is provided on the outer periphery on the front end side of the stop ring 70. The locking portion 75 is formed in a taper shape whose protrusion amount gradually decreases toward the tip, and the locking portion 75 enters the ferrule insertion hole 61 while expanding the rear end portion of the plug frame 60. Thus, it is locked in the locking hole 65.
[0060]
In order to hold the ferrule 10 in the plug frame 60 configured as described above, the ferrule 10 holding the optical fiber 1 is inserted into the ferrule insertion hole 61 of the plug frame 60, and the urging force previously inserted into the optical fiber core wire 2 is inserted. By sequentially inserting the spring 80 and the stop ring 70, the locking portion 75 of the stop ring 70 is locked in the locking hole 65 of the plug frame 60. Thereby, the stop ring 70 is fixed to the plug frame 60. At this time, the front end surface of the flange portion 33 of the ferrule 10 abuts on the projecting flange portion 63 of the plug frame 60, so that the ferrule 10 is positioned from the projecting hole 62 in a state where movement toward the front end side is restricted. The fixed amount protrudes and is biased and held forward in the axial direction.
[0061]
In addition, two engaging projections 66 that engage with the plug housing 50 are provided on the outer periphery of the plug frame 60 assembled in this way, and these engaging projections 66 are the engaging recesses of the plug housing 50. By engaging with 51, the plug frame 60 is held in the plug housing 50 so as to be movable within a predetermined range in the axial direction, thereby forming the oblique PC connector 40.
[0062]
In addition, such a ferrule 10 is formed, for example, by forming the front end surface of the ferrule tubular body 20 in a plane perpendicular to the axis of the optical fiber 1 and mounting it on the oblique PC connector 40, and by using an end surface polishing apparatus with respect to the axis. The inclined convex end surface 23 can be formed by polishing. Of course, the ferrule 10 can be polished alone.
[0063]
Here, an example of an end surface polishing apparatus for carrying out the method of the present invention will be described. FIG. 5 is a schematic sectional view of the end surface polishing apparatus.
[0064]
As shown in FIG. 5, the central portion of the first rotation transmission board 92 is fixed to the rotation shaft of the motor 91 for rotation, and the first rotation transmission board 92 has a plurality of concentric circles with the rotation center as a fulcrum. The first connecting pin 93 is fixed. The first connection pins 93 are rotatably connected to the eccentric portions of the corresponding rotation transmission plates 94, and the second connection pins 95 are fixed to the eccentric portions of the rotation transmission plates 94. Each second connection pin 95 is rotatably connected to the second rotation transmission board 96.
[0065]
On the other hand, the central portion of the drive gear 98 is fixed to the rotating shaft of the revolution motor 97, and the driven gear 99 is engaged with the drive gear 98. The driven gear 99 is fixed to the outer periphery of the lower part of the revolution transmission shaft 100, and the bearing tube portion 102 of the apparatus main body 101 is fitted to the upper outer periphery of the revolution transmission shaft 100. Then, the rotation transmission shaft 103 is rotatably fitted to the revolution transmission shaft 100 at a position eccentric from the rotation center by a predetermined amount, and the lower end portion of the rotation rotation shaft 103 is located at the center of the second rotation transmission plate 96. It is consolidated.
[0066]
A polishing surface plate 105 is detachably coupled to an upper end portion of the rotation rotating shaft 103 via a coupling member 104. A polishing member 106 is provided on the upper surface of the polishing surface plate 105 via an elastic member 107.
[0067]
Such a polishing surface plate 105 has a disk shape formed of metal or the like, and the surface on which the elastic member 107 is provided is such that the polishing surface of the polishing member 106 provided on the elastic member 107 is directed toward the center of rotation. Inclined concavely toward the center of rotation so as to incline in a concave shape.
[0068]
As such a polishing surface plate 105, a plurality of polishing surface plates 105 having different inclination angles of the surface on which the elastic member 107 is provided are prepared by each polishing step such as rough polishing, intermediate polishing, and finish polishing, which will be described in detail later. .
[0069]
The elastic member 107 provided on the polishing surface plate 105 is made of, for example, rubber, elastomer, resin, or the like. Specifically, members having different hardnesses may be used depending on each polishing process such as rough polishing, intermediate polishing, and finish polishing, which will be described later. Several are available.
[0070]
Further, examples of the polishing member 106 provided on the elastic member 107 include a polishing sheet having polishing abrasive grains made of diamond, silicon oxide, cerium oxide, silicon carbide, or the like.
[0071]
As the polishing member 106 made of this polishing sheet, a plurality of members having different abrasive grain sizes are prepared for each polishing step such as rough polishing, intermediate polishing and finish polishing.
[0072]
On the other hand, the apparatus main body 101 supports a jig board 120 to which a plurality of ferrules 10 or an oblique PC connector 40 holding the ferrules 10 is fixed by a support mechanism 110.
[0073]
Here, the support mechanism 110 and the jig board 120 will be described in detail.
[0074]
6 is a perspective view and a side view of the jig board, FIG. 7 is a top view of the jig board, FIG. 8A is a cross-sectional view taken along line AA ′ of FIG. 7, and FIG. It is principal part sectional drawing of the support mechanism 110 and the BB 'surface of FIG.
[0075]
As shown in the figure, the jig board 120 holds the oblique PC connector 40 holding the ferrule 10 in this embodiment, and is a jig in which a plurality of recesses 131 are provided in the circumferential direction in the circumferential direction. The instrument panel main body 130 and a plurality of holding members 140 provided corresponding to the respective recesses 131 are provided.
[0076]
The jig board main body 130 has a disk shape, and a plurality of recesses 131 are provided in the vicinity of the peripheral edge in the circumferential direction. The concave portion 131 holds the diagonal PC connector 40 between the concave portion 131 and the holding member 140 by fitting the tip of the diagonal PC connector 40 holding the ferrule tubular body 20. In this embodiment, 16 sets of the recess 131 and the holding member 140 are provided so that the jig board 120 can hold the 16 oblique PC connectors 40 at the same time, but the oblique PC connector 40 that can be held on the jig board 120 is provided. The number is not limited to this, and more books may be set.
[0077]
A cylindrical body 132 having a cylindrical shape that is fitted to the distal end portion of the ferrule cylindrical body 20 is provided on the bottom surface of the recess 131. This cylindrical body 132 penetrates in the thickness direction of the jig board main body 130 and cures only the tip end portion of the cylindrical body 20 for the ferrule of the oblique PC connector 40 held between the concave portion 131 and the holding member 140. It protrudes from the bottom surface of the tool panel main body 130.
[0078]
In addition, as will be described in detail later, the concave portion 131 and the cylindrical body 132 will be described later in detail. It is provided at an inclination angle so as to be inclined and held from the center toward the peripheral edge with respect to the thickness direction.
[0079]
In addition, the holding member 140 includes a support column 141 fixed corresponding to each recess 131 of the jig board main body 130, a support unit 142 provided on the outer periphery of the support column 141 so as to be movable in the axial direction, and a support column An urging spring 143 held between the support post 141 and the holding part 142 is provided on the outer peripheral surface of the part 141.
[0080]
The support post 141 is fixed to the jig board main body at the same inclination direction and angle as the corresponding recess 131 and the cylindrical body 132. In other words, in the present embodiment, the end portion of the column portion opposite to the fixed end portion is fixed so as to be inclined toward the peripheral edge side with respect to the thickness direction of the jig board main body.
[0081]
The holding portion 142 is fitted to the outer periphery of the column portion 141 and is provided so as to be movable in the axial direction of the column portion 141. The holding portion 142 extends from one end of the slide portion 144 and is located on the upper side of the recess 131. And an arm portion 145 that protrudes from the top.
[0082]
The arm portion 145 is provided with a rectangular fitting portion 146 penetrating in the thickness direction at the tip portion and penetrating on one side, and the fitting portion 146 is fitted to the rear end portion of the oblique PC connector 40. It has become.
[0083]
Further, an urging spring 143 is provided on the outer peripheral surface on the end portion side opposite to the fixed end portion of the column portion 141.
[0084]
The biasing spring 143 has one end abutting on the end of the slide portion 144 and the other end abutting on a stopper portion 147 provided on the end opposite to the end on which the support post 141 is fixed. The holding portion 142 is urged toward the axial concave portion 131 side of the column portion 141. That is, the holding portion 142 biased toward the concave portion 131 is inclined in a state where the tip portion of the ferrule tubular body 20 protrudes from the bottom surface of the jig board main body 130 by a predetermined amount between the holding portion 142 and the concave portion 131. Can be held.
[0085]
As described above, the jig board 120 is configured so that the rear end side of the oblique PC connector 40 is inclined by a predetermined amount from the center of the jig board main body 130 toward the peripheral edge side by the jig board main body 130 and the holding portion 140. Can be held.
[0086]
A boss 133 is provided at the center of the jig board main body 130. The boss portion 133 urges the jig board 120 toward the polishing member 106 by the support mechanism 110 and engages the support mechanism 110 so that the jig board 110 rotates in the rotation direction of the polishing member 106. Is preventing.
[0087]
Here, the support mechanism 110 for supporting the jig plate 120 is provided on the apparatus main body 101 so as to be movable to the polishing surface plate 105 side, and provided on the front end side of the support arm 111 to be cured. A pressing portion 112 fixed to the boss portion of the tool board 120 and a regulation pin 113 provided on the support arm 111 to regulate the movement of the jig board 120 in the rotational direction are provided. Is pressed in the direction of the polishing surface plate 105 by a pressing means (not shown) provided on the surface.
[0088]
That is, the support arm 111 pressed by the pressing means polishes the jig board 120 by the taper part 112 a provided at the tip of the pressing part 112 abutting the taper concave part 134 of the boss part 133 of the jig board 120. It is pressing in the direction of the surface plate 105.
[0089]
On the other hand, the restriction pin 113 is engaged with the restriction hole 135 of the boss 133 of the jig board 120, so that the jig board 120 is restricted from moving in the rotational direction accompanying the rotation of the polishing member 106.
[0090]
In other words, the jig plate 120 is biased toward the polishing surface plate 105 by the pressing portion 112 and held by the jig plate 120 in a state where movement in the rotational direction is restricted by the restriction pin 113 of the support mechanism 110. The PC connector 40 is supported on the polishing member 106 through the distal end surface 23 of the ferrule tubular body 20. Then, by rotating and swinging the polishing member 106, it is possible to form a convex distal end surface 23 that is inclined with respect to a surface perpendicular to the optical fiber axis at the distal end of the ferrule tubular body 20.
[0091]
Note that the pressing means for pressing the support arm 111 is not particularly limited, and examples thereof include a mechanism that can be manually pressed by a lever, a mechanism that can be automatically pressed by a drive motor, and the like. Further, the pressing means is preferably capable of grasping the pressure with which the front end surface 23 of the ferrule tubular body 20 is brought into contact with the polishing member 106. For example, it is preferable to provide a pressure detecting means such as a load cell.
[0092]
Further, the method of the present invention for polishing the end face of the ferrule 10 of the oblique PC connector 40 using the end face polishing apparatus will be described in detail. FIG. 9 is a plan view of the main part of the ferrule tubular body by the ferrule end surface polishing method, and FIG. 10 is a main part cross-sectional view of the ferrule and the end surface polishing apparatus by the ferrule end surface polishing method.
[0093]
First, from the state of the ferrule tubular body 20 shown in FIG. 9A, as shown in FIG. 9B, the tip of the ferrule tubular body 20 holding the optical fiber 1 is perpendicular to the optical fiber axis. A tip surface 223 having an outer diameter of 0.3 to 0.9 mm is formed.
[0094]
In this embodiment, a predetermined outer diameter is formed by forming a chamfered portion 24 in which the edge portion of the distal end surface 223 of the ferrule tubular body 20 is inclined by 30 to 45 degrees with respect to the optical fiber axis in the circumferential direction. The front end surface 223 of was formed.
[0095]
In the formation of the distal end surface 223, the distance between the apex of the convex distal end surface 23 formed by polishing the distal end surface 223 of the ferrule tubular body 20 in the subsequent step and the center of the end surface of the optical fiber 1 is 50 μm or less. In order to achieve this, the outer diameter of the front end surface 223 before polishing is 0.3 to 0.9 mm, but the chamfer 24 is inclined at an angle of 32.5 to 40 degrees before the front end surface is polished. By forming the outer diameter of 223 to 0.55 to 0.7 mm, it can be made 30 μm or less.
[0096]
Next, the front end surface 223 of the ferrule cylindrical body 20 is polished to form a convex front end surface 23 that is inclined with respect to a plane orthogonal to the optical fiber axis.
[0097]
Specifically, first, as shown in FIG. 10A, the front end surface 223 of the ferrule tubular body 20 is roughly polished to form the front end surface 23a.
[0098]
In this rough polishing, the ferrule cylindrical body 20 is brought into contact with the polishing surface of the polishing member 106 a while being inclined relatively, and is rotated more than the axial direction of the ferrule cylindrical body 20 and the ferrule cylindrical body 20. Rough polishing is performed so that the angle α formed with the polishing surface of the polishing member 106a on the center side becomes an obtuse angle.
[0099]
In the present embodiment, the jig plate 120 of the above-described end surface polishing apparatus has the rear end side of the ferrule tubular body 20 directed outward from the rotation center of the polishing member 106a with respect to the moving direction of the jig plate 120. Inclined and held, and the polishing surface of the polishing member 106a is inclined so as to be concave toward the rotation center, so that the axial direction of the ferrule tubular body 20 and the rotation center side from the ferrule tubular body 20 The angle α formed with the polishing surface of the polishing member 106a can be an obtuse angle.
[0100]
By moving the jig board 120 toward the polishing surface plate 105a in such a state, the front end surface 223 of the ferrule tubular body 20 is brought into contact with the polishing surface of the polishing member 106a relatively inclined. By rotating and swinging the polishing surface plate 105a, a convex tip surface 23a inclined with respect to the axis can be formed at the tip of the ferrule tubular body 20.
[0101]
The jig board 120 holds the ferrule tubular body 20 at an inclination of 8 degrees with respect to the vertical direction, and the inclination angle of the surface on which the elastic member 107a of the polishing surface plate 105a is provided, that is, the polishing surface of the polishing member 106a. Is preferably 0 to 0.3 degree with respect to the horizontal plane. In this embodiment, the jig board 120 holds the ferrule cylindrical body 20 at an angle of 8 degrees with respect to the vertical direction, and the surface on which the elastic member 107a of the polishing surface plate 105a is provided, that is, the polishing member 106a. The polished surface was inclined 0.125 degrees from the horizontal direction.
[0102]
The elastic member 107a used for the rough polishing was selected from a hardness range of 70 to 97 Hs, and a polishing sheet having a polishing abrasive grain size of 8 to 15 μm was used as the polishing member 106a.
[0103]
In such rough polishing, since the hardness of the elastic member 107a is relatively high, the ferrule tubular body 20 can be obtained even when the jig panel 120 holding the ferrule tubular body 20 is pressed with a relatively small pressure. The tip surface 23a having a stable inclination angle can be formed at the tip of the lens.
[0104]
In the present embodiment, the above-described jig panel 120 that can hold 16 ferrule tubular bodies 20 can be pressed against the ferrule tubular body 20 with a pressure of 0.74 to 1.47 N / piece. The pressing means only needs to press the jig panel 120 with a pressure of 11.8 to 23.5 N, and the pressing with such a relatively low pressure can be easily performed.
[0105]
Next, as shown in FIG. 10B, the front end surface 23a of the ferrule tubular body 20 is subjected to intermediate polishing to form the front end surface 23b.
[0106]
In this intermediate polishing, the ferrule tubular body 20 is contacted at an angle equivalent to that during rough polishing using a polishing member 106b made of a polishing sheet having a smaller abrasive grain size than the polishing member 106a during rough polishing. Then, the tip surface 23b is formed at the tip of the ferrule tubular body 20 by polishing.
[0107]
As the polishing member 106b, the particle size of the polishing abrasive grains is preferably between 0.5 μm and 4 μm. Here, a 1 μm polishing sheet was used and the elastic member 107a during rough polishing was used.
[0108]
In such a middle polishing step, the elastic member 107a is equivalent to rough polishing and has a relatively high hardness. Therefore, even if the jig panel 120 holding the ferrule tubular body 20 is pressed with a relatively small pressure, the elastic member 107a is used for the ferrule. A distal end surface 23 b with a stable inclination angle can be formed at the distal end of the cylindrical body 20.
[0109]
In the present embodiment, the above-described jig panel 120 that holds 16 ferrule tubular bodies 20 can be pressed against the ferrule tubular body 20 with a pressure of 0.74 to 2.06 N / piece. The jig board 120 may be pressed at a pressure of 11.8 to 32.9 N, and such pressing at a relatively low pressure can be easily performed.
[0110]
Next, as shown in FIG. 10C, the front end surface 23 b of the ferrule tubular body 20 is finish-polished to form the front end surface 23.
[0111]
In this final polishing, an elastic member 107b having a hardness lower than that of the elastic member 107a at the time of intermediate polishing is used, and a polishing member 106c having a smaller abrasive grain size than that of the polishing member 106b at the time of intermediate polishing is used. The cylindrical body 20 is inclined and brought into contact with the polishing surface of the polishing member 106c to form the axial direction of the ferrule cylindrical body 20 and the polishing surface closer to the rotation center than the ferrule cylindrical body 20. Final polishing is performed so that the angle is larger than that in the step of performing rough polishing and intermediate polishing.
[0112]
Actually, in the jig plate 120 of the end surface polishing apparatus described above, the inclination angle of the ferrule tubular body 20 held by the jig plate 120 cannot be changed. Therefore, the inclination angle of the polishing surface of the polishing member 106c is increased. ing. In the step of performing final polishing, the inclination angle of the polishing surface of the polishing member 106c is 0.4 to 1.3 degrees, preferably 0.8 to 1.0 degrees, more preferably 0.9 degrees with respect to the horizontal plane. It is good to do.
[0113]
In order to increase the inclination angle of the polishing member 106c in this way, the polishing surface of the polishing member 106c is made to be a surface by using the polishing surface plate 105b whose surface to which the elastic member 107b is fixed is inclined at a larger angle than the polishing surface plate 105a. Further, the ferrule tubular body 20 can be brought into contact with the polishing surface of the polishing member 106c so as to have a larger angle than the step of performing rough polishing and intermediate polishing.
[0114]
In this embodiment, the elastic member 107b at the time of final polishing is selected from a range of hardness of 60 to 80 Hs so that the hardness is lower than the hardness selected when performing rough polishing and intermediate polishing. That's fine.
[0115]
Further, as the polishing member 106c at the time of final polishing, a polishing sheet having a polishing abrasive grain size of 0.02 μm was used.
[0116]
In this manner, by increasing the angle at which the ferrule tubular body 20 is brought into contact with the polishing surface of the polishing member 106c as compared with rough polishing and intermediate polishing, the tip surface of the optical fiber 1 is brought into contact with the polishing member 106c at the beginning of polishing. Only the ferrule tubular body 20 is polished without contact. As the polishing proceeds, the tip surface of the optical fiber 1 can be gradually brought into contact with the polishing member 106c for polishing. Thereby, cracking of the optical fiber 1 at the time of polishing can be prevented, and polishing with good yield can be performed with high accuracy.
[0117]
In such finish polishing, since the hardness of the polishing member 106c is relatively high, even if the jig panel 120 holding the ferrule tubular body 20 is pressed with a relatively small pressure, the ferrule tubular shape A tip surface 23 having a stable inclination angle can be formed at the tip of the body 20.
[0118]
Specifically, in the present embodiment, the ferrule tubular body 20 can be pressed with a pressure of 0.74 to 1.23 N / piece, and the 16 ferrule tubular bodies 20 are held. In the jig board 120, the jig board 120 may be pressed with a pressure of 11.8 to 19.6 N, and such pressing with a relatively low pressure can be easily performed.
[0119]
In this way, the front end surface of the ferrule tubular body 20 before polishing is formed to have a predetermined outer diameter, and a series of rough polishing, intermediate polishing, and finish polishing are performed, whereby the ferrule tubular body 20 A convex tip surface 23 having a vertex that is 50 μm or less from the center of the tip surface of the optical fiber 1 can be formed at the tip with high accuracy. That is, the spherical eccentricity can be 50 μm or less.
[0120]
Note that the method of polishing the ferrule 10 of the oblique PC connector 40 is not limited to the ferrule 10 described above, and can be applied to, for example, a ferrule for an oblique PC connector having a conventional shape and polished with high accuracy. it can.
[0121]
Although the ferrule has been described above, the above-described polishing method can be applied to a ferrule in which the ferrule and the flange member are integrated. Further, after polishing the ferrule cylindrical body to form a pre-dome ferrule, the optical fiber may be fixed in the ferrule and polished.
[0122]
(Embodiment 2)
FIG. 11 is a perspective view, an axial plan view, and a cross-sectional view showing another embodiment of the ferrule. In addition, the same code | symbol is attached | subjected to the equivalent member demonstrated in Embodiment 1 of the ferrule mentioned above, and the overlapping description is abbreviate | omitted.
[0123]
As shown in FIG. 11, a ferrule 10A according to another embodiment includes a ferrule tubular body 20A having an outer diameter of 1.25 mm, and a collar fitted to one end of the ferrule tubular body 20A. Member 30.
[0124]
The distal end surface 23A of the ferrule tubular body 20A is a convex surface inclined with respect to a surface orthogonal to the optical fiber axis together with the distal end surface of the optical fiber 1, as in the first embodiment. In this embodiment, the convex spherical surface is formed. It is formed of an aspheric surface similar to
[0125]
That is, the distal end surface 23A is a convex surface having a large curvature radius in the vicinity of the peripheral edge on the tilt direction protruding side and a small curvature radius in the vicinity of the peripheral edge on the other side in the tilt direction with respect to the curvature radius of the central region in the vicinity of the optical fiber 1. The radius of curvature of the central region in the vicinity of the optical fiber 1 and the radius of curvature in the vicinity of the peripheral edge on both sides in the tilt direction are formed in a predetermined range, in this embodiment, 5 mm to 12 mm.
[0126]
Furthermore, the tip surface 23A formed in the convex shape of the ferrule tubular body 20A is compared with the amount of change per unit distance of the radius of curvature from the central region of the optical fiber 1 to the peripheral edge on the inclined direction protruding side, It is formed so that the amount of change per unit distance of the radius of curvature up to the peripheral edge on the other side in the tilt direction is small.
[0127]
Further, a small-diameter cylindrical portion 25 having an outer diameter equivalent to that of the distal end surface 23A is provided at the distal end portion of the ferrule tubular body 20A.
[0128]
The outer diameter of the small-diameter cylindrical portion 25 is provided to form the distal end surface 23A having a predetermined outer diameter before the convex distal end surface 23A is formed by polishing. Since the outer diameter of the vertical front end surface of the cylindrical body 20A for polishing is 0.3 to 0.9 mm, the outer diameter of the small-diameter cylindrical portion is also 0.3 to 0.9 mm.
[0129]
Further, a chamfered portion 24A is formed at an edge portion where a step due to the outer diameter difference from the small diameter cylindrical portion 25 of the ferrule cylindrical body 20A is formed.
[0130]
Such a ferrule tubular body 20A can be formed easily and with high precision by polishing in the same manner as in the first embodiment described above after forming the small-diameter tubular portion 25 in advance.
[0131]
In order to make the distance between the apex of the convex tip surface 23A of the ferrule cylindrical body 20A and the center of the tip surface of the optical fiber 1 equal to or less than 50 μm, the tip surface and the small diameter cylindrical portion before polishing This can be realized by setting the outer diameter of 25 to 0.3 to 0.9 mm, but to 30 μm or less by forming the outer diameter of the small-diameter cylindrical portion 25 and the tip surface 23A to 0.55 to 0.7 mm. Can do. In addition, the small diameter cylindrical part 25 can be formed by grinding etc., for example.
[0132]
(Other embodiments)
As mentioned above, although Embodiment 1 and 2 by the method of this invention were demonstrated, the grinding | polishing method of the ferrule of the diagonal PC connector of this invention is not limited to what was mentioned above.
[0133]
For example, in the first embodiment described above, the polishing surface plates 105, 105 a, 105 b are inclined in a concave shape toward the rotation center, and the rear end side of the diagonal PC connector 40 on the jig plate 120 is the thickness of the jig plate main body 130. The tip surface of the ferrule tubular body has a radius of curvature in the central region near the optical fiber by providing an inclination angle that is inclined from the center to the peripheral edge with respect to the direction, that is, held in an inverted C shape. On the other hand, it has a convex shape with a large radius of curvature near the peripheral edge on the protruding side in the tilt direction and a small radius of curvature near the peripheral edge on the other side in the inclined direction, but the polishing surface plate is inclined convexly toward the center of rotation. Even if the jig board is provided at an inclination angle such that the rear end side of the oblique PC connector is inclined toward the center direction with respect to the thickness direction of the jig board body, that is, held in a C shape. Can be polished
[0134]
Further, for example, in the first embodiment described above, the jig board 120 of the end surface polishing apparatus holds the inclined PC connector 40 in an inclined state, and the polishing surfaces of the polishing members 106a to 106c are subjected to rough polishing, intermediate polishing, and final polishing. The angle at each polishing step is adjusted by changing the inclination angle, but the present invention is not limited to this. For example, the polishing surface of the polishing member does not change the inclination angle at each polishing step, and the ferrule is cylindrical. The jig board holding the body may be structured such that the inclination angle of the ferrule tubular body can be changed in each polishing step.
[0135]
Thus, the end surface polishing apparatus is not limited to the above-described one as long as the angle formed by the axial direction of the ferrule tubular body and the polishing surface of the polishing member can be adjusted in each polishing step.
[0136]
Moreover, in Embodiment 1 and 2 mentioned above, although the ferrule for MU type diagonal PC connectors was illustrated, it is good also as a ferrule for diagonal PC connectors, such as LC type.
[0137]
Further, in Embodiments 1 and 2 described above, the outer diameter of the ferrule tubular body is set to 1.25 mm. However, the present invention is not limited to this. A ferrule for an oblique PC connector such as a mold may be used.
[0138]
Even with such a ferrule, it is easy and highly accurate depending on the outer diameter of the front end surface before polishing, the adjustment of the inclination angle of each polishing step, the hardness of the elastic member, and the like, as in the first and second embodiments. It is possible to form a convex tip end surface that is inclined in a straight line.
[0139]
【The invention's effect】
As described above, in the present invention, polishing is performed by increasing the angle at the time of final polishing as compared with the angle at which the cylindrical body for ferrules at the time of rough polishing and intermediate polishing is brought into contact with the polishing surface of the polishing member. Therefore, the optical fiber can be prevented from cracking and highly accurate polishing can be performed. Further, by performing polishing using an elastic member having a predetermined hardness, stable polishing can be performed even when the ferrule tubular body is pressed at a low pressure. As a result, a ferrule of an oblique PC connector with low insertion loss and high return loss can be realized.
[Brief description of the drawings]
FIG. 1 is a perspective view, an axial plan view, and a cross-sectional view of a ferrule according to Embodiment 1 of the present invention.
FIG. 2 is a graph showing a relationship between a distance in a tilt direction from a central region in the vicinity of an optical fiber on a distal end surface of a ferrule tubular body according to Embodiment 1 of the present invention and a radius of curvature.
FIG. 3 is an exploded perspective view of the oblique PC connector according to the first embodiment of the present invention.
FIGS. 4A and 4B are an exploded plan view and an assembled cross-sectional view of the oblique PC connector according to the first embodiment of the present invention. FIGS.
FIG. 5 is a schematic cross-sectional view of the end surface polishing apparatus according to the first embodiment of the present invention.
FIGS. 6A and 6B are a perspective view and a side view of the jig board according to the first embodiment of the present invention. FIGS.
FIG. 7 is a top view of the jig board according to the first embodiment of the present invention.
8A and 8B are cross-sectional views of the jig board according to the first embodiment of the present invention, in which FIG. 8A is a support mechanism and a cross-sectional view taken along the line AA ′ in FIG. 7, and FIG. FIG.
FIG. 9 is a plan view of a principal part of the ferrule tubular body showing the ferrule end face polishing method according to the first embodiment of the present invention;
FIG. 10 is a cross-sectional view of main parts of the ferrule and the end surface polishing apparatus showing the ferrule end surface polishing method according to the first embodiment of the present invention.
FIG. 11 is a perspective view, an axial plan view, and a cross-sectional view of a ferrule according to Embodiment 2 of the present invention.
FIG. 12 is a perspective view, a plan view in the axial direction, and a plan view in the end face direction of a ferrule according to the prior art.
[Explanation of symbols]
10, 10A ferrule
20, 20A Ferrule tubular body
23, 23a, 23b, 23A Tip surface
24, 24A Chamfer
25 Small diameter cylindrical part
30 collar
33 collar
40 diagonal PC connector
50 plug housing
60 plug frame
70 Stop ring
80 Biasing spring
105, 105a, 105b Polishing surface plate
106, 106a, 106b, 106c Polishing member
107, 107a, 107b Elastic member
110 Support mechanism
120 Jig panel

Claims

The tip end surface of a ferrule used for an oblique PC connector that connects the oblique polished surfaces of optical fibers to each other on a polishing member on an elastic member that is mounted on a polishing surface plate supported and rotated by an apparatus main body. In the ferrule polishing method of an oblique PC connector that forms a convex surface inclined with respect to a surface orthogonal to the optical fiber axis by pressing and polishing the ferrule tip surface,
Forming a tip surface having an outer diameter smaller than the outer diameter of the ferrule tubular body at the tip of the ferrule tubular body, and the ferrule tubular body relative to the polishing surface of the polishing member. A step of performing rough polishing and intermediate polishing so that an angle formed between the axial direction and the polishing surface closer to the rotation center than the ferrule tubular body is an obtuse angle, and the elasticity The member has a lower hardness than the step of rough polishing and intermediate polishing, and the ferrule tubular body is inclined relative to the polishing surface, and its axial direction and the ferrule tubular body rotate. And a step of performing final polishing so that the angle formed with the polishing surface on the center side is larger than the step of performing the rough polishing and intermediate polishing, and the outer diameter of the tip surface is 0.3 mm to 0.9mm and the rough polishing process Then, the hardness of the elastic member is selected from the range of 70Hs to 97Hs, the hardness of the elastic member is selected from the range of 70Hs to 97Hs in the intermediate polishing step, and the hardness of the elastic member in the step of finishing polishing. Is selected from the range of 60Hs to 80Hs ,
In the rough polishing step, the inclined PC connector ferrule polishing method is characterized in that an inclination angle of a polishing surface of the polishing member is 0 degree to 0.3 degree with respect to a horizontal plane .

The tip end surface of a ferrule used for an oblique PC connector that connects the oblique polished surfaces of optical fibers to each other on a polishing member on an elastic member that is mounted on a polishing surface plate supported and rotated by an apparatus main body. In the ferrule polishing method of an oblique PC connector that forms a convex surface inclined with respect to a surface orthogonal to the optical fiber axis by pressing and polishing the ferrule tip surface,
Forming a tip surface having an outer diameter smaller than the outer diameter of the ferrule tubular body at the tip of the ferrule tubular body, and the ferrule tubular body relative to the polishing surface of the polishing member. A step of performing rough polishing and intermediate polishing so that an angle formed between the axial direction and the polishing surface closer to the rotation center than the ferrule tubular body is an obtuse angle, and the elasticity The member has a lower hardness than the step of rough polishing and intermediate polishing, and the ferrule tubular body is inclined relative to the polishing surface, and its axial direction and the ferrule tubular body rotate. And a step of performing final polishing so that the angle formed with the polishing surface on the center side is larger than the step of performing the rough polishing and intermediate polishing, and the outer diameter of the tip surface is 0.3 mm to 0.9mm and the rough polishing process Then, the hardness of the elastic member is selected from the range of 70Hs to 97Hs, the hardness of the elastic member is selected from the range of 70Hs to 97Hs in the intermediate polishing step, and the hardness of the elastic member in the step of finishing polishing. Is selected from the range of 60Hs to 80Hs,
In the method of performing intermediate polishing, the inclined PC connector ferrule polishing method is characterized in that an inclination angle of a polishing surface of the polishing member is set to 0 degree to 0.3 degree with respect to a horizontal plane .

The tip end surface of a ferrule used for an oblique PC connector that connects the oblique polished surfaces of optical fibers to each other on a polishing member on an elastic member that is mounted on a polishing surface plate supported and rotated by an apparatus main body. In the ferrule polishing method of an oblique PC connector that forms a convex surface inclined with respect to a surface orthogonal to the optical fiber axis by pressing and polishing the ferrule tip surface,
Forming a tip surface having an outer diameter smaller than the outer diameter of the ferrule tubular body at the tip of the ferrule tubular body, and the ferrule tubular body relative to the polishing surface of the polishing member. is inclined to the brought into contact, a step of performing rough grinding and the medium grinding angle is set to be an obtuse angle with the Institute Migakumen center of rotation side from the axial direction and the ferrule tubular body, the The elastic member has a lower hardness than the rough polishing and intermediate polishing steps, and the ferrule tubular body is inclined relative to the polishing surface, and the axial direction of the ferrule tubular body is more than that of the ferrule tubular body. And a step of performing final polishing such that the angle formed with the polishing surface on the rotation center side is larger than the step of performing the rough polishing and intermediate polishing, and the outer diameter of the tip surface is 0.3 mm ~ 0.9mm, the rough polishing process Then, the hardness of the elastic member is selected from the range of 70Hs to 97Hs, the hardness of the elastic member is selected from the range of 70Hs to 97Hs in the intermediate polishing step, and the hardness of the elastic member in the step of finishing polishing. Is selected from the range of 60Hs to 80Hs,
In the step of performing the final polishing, the inclined PC connector ferrule polishing method is characterized in that the angle of inclination of the polishing surface of the polishing member is set to 0.4 to 1.3 degrees with respect to a horizontal plane .

The tip end surface of a ferrule used for an oblique PC connector that connects the oblique polished surfaces of optical fibers to each other on a polishing member on an elastic member that is mounted on a polishing surface plate supported and rotated by an apparatus main body. In the ferrule polishing method of an oblique PC connector that forms a convex surface inclined with respect to a surface orthogonal to the optical fiber axis by pressing and polishing the ferrule tip surface,
Forming a tip surface having an outer diameter smaller than the outer diameter of the ferrule tubular body at the tip of the ferrule tubular body, and the ferrule tubular body relative to the polishing surface of the polishing member. A step of performing rough polishing and intermediate polishing so that an angle formed between the axial direction and the polishing surface closer to the rotation center than the ferrule tubular body is an obtuse angle, and the elasticity The member has a lower hardness than the step of rough polishing and intermediate polishing, and the ferrule tubular body is inclined relative to the polishing surface, and its axial direction and the ferrule tubular body rotate. And a step of performing final polishing so that the angle formed with the polishing surface on the center side is larger than the step of performing the rough polishing and intermediate polishing, and the outer diameter of the tip surface is 0.3 mm to 0.9mm and the rough polishing process Then, the hardness of the elastic member is selected from the range of 70Hs to 97Hs, the hardness of the elastic member is selected from the range of 70Hs to 97Hs in the intermediate polishing step, and the hardness of the elastic member in the step of finishing polishing. Is selected from the range of 60Hs to 80Hs,
The method of forming a front end surface of the ferrule tubular body includes forming a front end surface having an outer diameter of 0.55 mm to 0.7 mm at the front end .

The tip end surface of a ferrule used for an oblique PC connector that connects the oblique polished surfaces of optical fibers to each other on a polishing member on an elastic member that is mounted on a polishing surface plate supported and rotated by an apparatus main body. In the ferrule polishing method of an oblique PC connector that forms a convex surface inclined with respect to a surface orthogonal to the optical fiber axis by pressing and polishing the ferrule tip surface,
Forming a tip surface having an outer diameter smaller than the outer diameter of the ferrule tubular body at the tip of the ferrule tubular body, and the ferrule tubular body relative to the polishing surface of the polishing member. A step of performing rough polishing and intermediate polishing so that an angle formed between the axial direction and the polishing surface closer to the rotation center than the ferrule tubular body is an obtuse angle, and the elasticity The member has a lower hardness than the step of rough polishing and intermediate polishing, and the ferrule tubular body is inclined relative to the polishing surface, and its axial direction and the ferrule tubular body rotate. And a step of performing final polishing so that the angle formed with the polishing surface on the center side is larger than the step of performing the rough polishing and intermediate polishing, and the outer diameter of the tip surface is 0.3 mm to 0.9mm and the rough polishing process Then, the hardness of the elastic member is selected from the range of 70Hs to 97Hs, the hardness of the elastic member is selected from the range of 70Hs to 97Hs in the intermediate polishing step, and the hardness of the elastic member in the step of finishing polishing. Is selected from the range of 60Hs to 80Hs,
In the step of forming the distal end surface of the ferrule tubular body, a tubular portion having a small diameter equivalent to the outer diameter of the distal end surface is formed at the distal end portion of the ferrule tubular body . Ferrule polishing method.

The tip end surface of a ferrule used for an oblique PC connector that connects the oblique polished surfaces of optical fibers to each other on a polishing member on an elastic member that is mounted on a polishing surface plate supported and rotated by an apparatus main body. In the ferrule polishing method of an oblique PC connector that forms a convex surface inclined with respect to a surface orthogonal to the optical fiber axis by pressing and polishing the ferrule tip surface,
Forming a tip surface having an outer diameter smaller than the outer diameter of the ferrule tubular body at the tip of the ferrule tubular body, and the ferrule tubular body relative to the polishing surface of the polishing member. A step of performing rough polishing and intermediate polishing so that an angle formed between the axial direction and the polishing surface closer to the rotation center than the ferrule tubular body is an obtuse angle, and the elasticity The member has a lower hardness than the step of rough polishing and intermediate polishing, and the ferrule tubular body is inclined relative to the polishing surface, and its axial direction and the ferrule tubular body rotate. And a step of performing final polishing so that the angle formed with the polishing surface on the center side is larger than the step of performing the rough polishing and intermediate polishing, and the outer diameter of the tip surface is 0.3 mm to 0.9mm and the rough polishing process Then, the hardness of the elastic member is selected from the range of 70Hs to 97Hs, the hardness of the elastic member is selected from the range of 70Hs to 97Hs in the intermediate polishing step, and the hardness of the elastic member in the step of finishing polishing. Is selected from the range of 60Hs to 80Hs,
The method of forming a front end surface of the ferrule tubular body includes forming a front end surface having an outer diameter of 0.3 mm to 0.9 mm at the front end .

The tip end surface of a ferrule used for an oblique PC connector that connects the oblique polished surfaces of optical fibers to each other on a polishing member on an elastic member that is mounted on a polishing surface plate supported and rotated by an apparatus main body. In the ferrule polishing method of an oblique PC connector that forms a convex surface inclined with respect to a surface orthogonal to the optical fiber axis by pressing and polishing the ferrule tip surface,
Forming a tip surface having an outer diameter smaller than the outer diameter of the ferrule tubular body at the tip of the ferrule tubular body, and the ferrule tubular body relative to the polishing surface of the polishing member. A step of performing rough polishing and intermediate polishing so that an angle formed between the axial direction and the polishing surface closer to the rotation center than the ferrule tubular body is an obtuse angle, and the elasticity The member has a lower hardness than the step of rough polishing and intermediate polishing, and the ferrule tubular body is inclined relative to the polishing surface, and its axial direction and the ferrule tubular body rotate. And a step of performing final polishing so that the angle formed with the polishing surface on the center side is larger than the step of performing the rough polishing and intermediate polishing, and the outer diameter of the tip surface is 0.3 mm to 0.9mm and the rough polishing process Then, the hardness of the elastic member is selected from the range of 70Hs to 97Hs, the hardness of the elastic member is selected from the range of 70Hs to 97Hs in the intermediate polishing step, and the hardness of the elastic member in the step of finishing polishing. Is selected from the range of 60Hs to 80Hs,
A method of polishing a ferrule for an oblique PC connector, wherein the elastic member has a thickness of 1 mm to 5 mm .