JP2004264072A

JP2004264072A - Photoelectric type displacement detection apparatus

Info

Publication number: JP2004264072A
Application number: JP2003052465A
Authority: JP
Inventors: Takahiro Imai; 崇博今井; Yoshio Sakamoto; 良雄坂本; Toru Shinzo; 徹新造; Hiroshi Miyazawa; 寛宮澤
Original assignee: Kenwood KK
Current assignee: Kenwood KK
Priority date: 2003-02-28
Filing date: 2003-02-28
Publication date: 2004-09-24
Anticipated expiration: 2023-02-28
Also published as: JP4278032B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoelectric type displacement detection apparatus having a simple adjustment mechanism, capable of improving optical efficiency, having high reliability and stable quality for detecting changes in sound pressure, wind pressure, hydraulic pressure, and vibrations. <P>SOLUTION: In the photoelectric type displacement detection apparatus, a light emitting part and a light receiving part are arranged at locations opposed to a reflecting surface of a displacement body 1 having a pressure receiving surface and the reflecting surface. The light emitting part and the light receiving part are end parts of rod-like photoconductive paths 5 and 6 made of glass or a light transmitting resin having a refractive index distribution from their axis centers to their peripheries. Displacements of the displacement body are detected by radiating light to the reflecting surface of the displacement body 1 by the light emitting part and receiving reflected light from the reflecting surface of the displacement body 1 at the light receiving part. The reflecting surface is formed in a dome shape having a desired radius size, and a pair of the rod-like photoconductive paths 5 and 6 are arranged at a desired interval with their axis centers in parallel. Overall peripheral parts of the rod-like photoconductive paths 5 and 6 are fixed from their tip parts to the side opposite to the reflecting part. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は気体、液体または固体の移動または振動を観測する光電式変位検出装置に係わり、特に光学的検出部において観測対象と媒質と触れ合う変位部の反射面、および光源および受光素子への伝送を行う棒状光導路の支持並びに筐体の構造に関するものである。
【０００２】
【従来の技術】
従来の実用化された光電式変位検出装置の例として特開２０００−８８５２０に開示された光学式音響電気信号変換装置の構成を図１６に示す。図１６に示すごとく平面状の測定媒体面１００を用いており、該平面状の測定媒体面１００の受音側と反対側の面を光反射面として用い、図１６に示すごとく光源、例えば、発光ダイオード等発光素子から放射された光は、投光側の光ファイバ１０１の一方の端面から入光し、更に、光ファイバ１０１内を通過し、他方の端面１０１ａより放射され、測定媒体面１００の反射面の所定箇所、すなわち、略中央部に投光される。
【０００３】
投光された光は、前記測定媒体面１００の反射面により反射され、受光側の光ファイバ１０２の端面１０２ａに到り、該端面１０２ａより入光しさらに光ファイバ１０２内を通過し、他方の端面より放射され、受光素子の所定面に投光される。尚、測定媒体面１００の反射面側に設置される前記投光側の光ファイバ１０１の端面１０１ａおよび受光側の光ファイバ１０２の端面１０２ａは光ファイバ光軸に対して所定の角度θに設定し、尚且つ光ファイバ１０１および光ファイバ１０２の夫々の光軸が所定の角度αをなすように光ファイバ１０１および光ファイバ１０２は保持具１０３の夫々の貫通１０３ａおよび１０３ｂに挿通されて接合面１０４で接合されるように保持されている。また、光ファイバ１０１および１０２の端面と測定媒体面１００とのクリアランスが所定の寸法に設定装着されている。
【０００４】
また、特開２００２−１８６０９９に開示された光学式音響電気信号変換装置の構成を図１７に示す。この光学式音響電気信号変換装置は、図１７に示すごとく、投光側の光ガイド１１１と受光側の光ガイド１１２各々を不透明部１１３を介して平行に隣接させ、夫々の光ファイバの光軸と垂直の最上面１１１ａおよび１１２ａを平面状の膜１１０の反射面に対して所望のクラクリアランスを保ち、尚且つ、前記光ファイバを垂直に配置せしめ、該光ファイバ１１１、１１２の先端部（最上面１１１ａおよび１１２ａ）のみならず、側面（上側面１１１ｂ、１１２ｂをも光軸に対して１５°の角度をなすように研磨し、膜１１０の変位を検出する構成となっている。これらの従来例においては、次のような重大な欠点が存在する。
【０００５】
以下、従来例の欠点を説明するが、従来例では２本の光ファイバを所定の角度で配置し、更に該光ファイバの先端部を隣接せしめ、しかも端部の投光面と受光面を反射面に対し所定の角度および平坦度を有した状態に加工せねばならず、工数が極めて多くなると共に、加工精度のバラツキが多いことは周知のところである。
【０００６】
しかも、前もってファイバ先端部を加工する場合はさらに加工工数が多くなり、加工精度がが得にくいことは勿論のところで、加工精度が得られたとしても左右対称に装着するにおいてもバラツキが発生することは当然のことである。
【０００７】
以上のことから、上記従来例は、量産には不向きな構造であるし、量産に対応するためには専用の工作設備等の導入が必要で、更には、前記精度を維持するために、組立て作業の練度向上が必須条件となる。従って、作業者の教育、および訓練等を計らねば、定められた品質の維持を保つことは困難である。すなわち、熟練作業者が常に必要であり、量産を前提とした工業生産を行う場合、大きな障害となることは明白である。
【０００８】
また、従来例は、一定の精度を得た光ファイバ先端部が振動板反射面に対向して設置され、尚且つ平面状の振動板を有する構造であるため、反射面は必然的に平面であり、該平面反射面に投光および受光し、その振動板の変異を検知する構造である。従って、実用的な感度を得るために光学構造上反射面および前記ファイバ先端部とのクリアランスは可能な限り狭い状態であることが好ましく、該構造上の特徴から、約１０μという極めて狭いクリアランスにて設置せざるを得ないことは周知のところである。
【０００９】
従って、従来例に於ける、現状のクリアランスでは、環境変化の大きい状況下において、例えば、湿度が多く、尚且つ温度変化が大きい環境下等では、結露等の現象が頻繁に起きる。このような場合、前記、振動板と光ファイバの間隙に水分が塊として入り込み、振動板の振幅に支障を来たすという検出装置の機能として致命的な事態を発生する等の極めて重大な欠点を有している。
【００１０】
【特許文献１】
特開２０００−８８５２０号公報（第２、３頁、図２）
【００１１】
【特許文献２】
特開２００２−１８６０９９号公報（第３頁、図２）
【００１２】
【発明が解決しようとする課題】
上記従来例のような光学式音響電気信号変換装置を製作する場合、投光用光ファイバおよび、受光用の光ファイバを一定角度を持たせ尚且つ各々の光ファイバの先端部を一定角度に保ちつつ端面研磨が必要であるし、更には一対の光ファイバの取付中心線に直角になるように、夫々光ファイバ中心線の延長線上の交点に振動板が位置するように振動板を固定する必要がある。これらの手法は研磨加工のみならず組立て工程なおいても、所定の精度を要求されるために専用の調整装置および、熟練した作業が必要で調整工程に於ける工数が増加し、生産時に於ける大きなコストアップの要因となっていた。また、更に従来例に於ける、振動板と一対の光ファイバの先端部とのクリアランスでは、環境変化の大きい状況下において、光学式音響電気信号変換装置の機能として致命的な事態を発生させる等の極めて重大な欠点を有している。
【００１３】
更に従来例の平面状の反射面を有した光学式音響電気信号変換装置の場合、投光ファイバから出射された光が反射面に反射し、受光ファイバに受光されるまでの間、当然のことながら集光効果は得られない。従って、光学的効率に限度がある点は否めない構造であることは、明らかである。
【００１４】
本発明はかかる上記従来例の欠点に鑑みてなされたものであって、その目的とするとするところは、調整機構が簡単であり、調整の工程を減少せしめ、量産性に的し、尚且つ基本的に変位する反射面と対向する導光路の先端部とのクリアランスを広げても差し支えない構造を有し、また、更に光学的効率を向上せしめ、結果的に信頼性に富み且つ品質の安定した音圧、風圧、水圧、振動などの変化検出を目的とした光電式変位検出装置を提供することにある。
【００１５】
【課題を解決するための手段】
上記の課題を解決するために、本発明の光電式変位検出装置は、変位部の一部をドーム形状に成型し、該ドーム内面を反射面として用いることにより集光効果をもたせ、一対の投光用および受光用棒状導光路の固定角度を平行に配置しても基本的に支障のない構造とし、更に、前記捧状導光路対の先端部と変位部反射面とのクリアランスを大幅に広げても差し支えない構造とした。
【００１６】
また、捧状導光路を固定するフォルダを設け、該フォルダに棒状導光路が平行に配置できる所定間隔の孔、若しくは棒状導光を２本まとめて平行に入る孔を設け、該フォルダに前記光ファイバを接着固定した後、フォルダごと投光および受光先端部を研磨する構造、並びに製造方法を採用し、更には、設計目的に応じて該フォルダとしてフェルールを用いることにした。
【００１７】
【発明の実施の形態】
本発明の第１の実施例としてを棒状導光路として光ファイバを用い、音圧検出する例を以下図面によって説明する。図１の断面図に示すごとく、フォルダ３および、フォルダケース４および変位体を用いた本実施例の場合、音圧検出を事例とするため、以下変位体を振動板１と記す。該振動板１、および振動板ケース２、および光ファイバ５、６から構成されている。尚、前記フォルダ３に装着した光ファイバ５、６の他方の端部に装着する発光素子、および受光素子、並びに該素子の配置構造および該素子を駆動するための電気回路等は省略してある。
【００１８】
この実施例の場合、フォルダ３およびフォルダケース４はアルミニューム製であるが、フォルダ３にセラミックまたはプラスチックを用いることもできる。振動板１は、耐熱フィルムを熱圧成型し、形成されたドーム内面に金属蒸着および表面処理等を施し、所定の反射率および、所望の表面粗度を得ている。以下フォルダ３の詳細を説明する。フォルダ３は概ね棒状で、図４の断面図に示すような形状をしており、長さは１８ｍｍ、最大太さは図で示すところの底部３ｇは直径６．６ｍｍ部分の長さは５．１ｍｍである。
【００１９】
更に、該底部３ｇより左方にねじ部３ａ（Ｍ５細目）を設けてあり、該ねじ部３ａの長さは約６ｍｍである。ねじ部３ａの左部側には直径４ｍｍ、長さ３．８ｍｍのケースガイド部３ｅが設けられており、更にその上部に直径１．５５ｍｍ、長さ２．４ｍｍからなるファイバフォルダ部３ｆが設けられている。該ファイバフォルダ部３ｆにセンター振り分け０．３５ｍｍの位置で、左方に向かって垂直に直径０．２６ｍｍの孔（以下、ファイバ先端部保持孔３ｃと記す）を２箇所設けた。また、該フォルダ右端部より左端部に向けて、直径６．６ｍｍ垂直に深さ１４．９ｍｍの孔（以下、ファイバ通し孔３ｂと記す）を併せて設けた。
【００２０】
従って、２箇所のファイバ先端部保持孔３ｃは図のごとく、ファイバ通し孔３ｂと繋がつており、このファイバ先端部保持孔３ｃの長さは約２．８ｍｍである。更に、図４（ａ）の平面図、図４（ｂ）の正面図で示すごとく、ファイバフォルダ部３ｆおよび前記ケースガイド部３ｅを幅１．２ｍｍ残して、ファイバフォルダ部３ｆの先端部から左方に向って長さ５．９ｍｍにて切削加工を施している。従って、図４（ｃ）の断面図に示す如ぐ、前記ファイバ前記通し孔３ｂが露出し、ファイバホルダ３ｆの右側にはケースガイド部３ｅを貫通した窓部３ｄが設けられる構造となる。
【００２１】
以下、フォルダケース４の詳細を説明する。概ね筒状で、図２の断面図に示すような形状をしており、長さは１４ｍｍ、最大太さは図で示す略全域にて直径６．６ｍｍで、左方の振動板押え部４ａが振動板ケース２に装着する寸法となっており、直径６ｍｍで、長さが２．２ｍｍとなっている。また、下端部より上方に向かい、ねじ部４ｂ（Ｍ５細目）を設けてあり、該ねじ部４ｂの長さは約６．２ｍｍで、前記フォルダ３に対応したもので更に該ねじ部４ｂの左方は直径４ｍｍのフォルダケース内面となっており、この部分に前記フォルダのケースガイド部３ｅが嵌合挿入されるため、この部分の寸法は嵌め合い寸法となっている。
【００２２】
以下、振動板ケース２の詳細を説明する。概ねキャップ筒状で図２の断面図に示すような形状をしており、長さは６．２ｍｍ、最大太さは図で示すところの全域において直径６．６ｍｍで、右側が振動板１の装着に対応した寸法となっており、直径６ｍｍで該部分（以下、ケース挿入部２ｃと記す）の長さが２ｍｍとなっている。該ケース挿入部２ｃに前記フォルダケース４の振動板押え部４ａが挿入されるので、該部分の寸法は嵌め合い寸法となっている。更にケース挿入部２ｃの図面左端部に振動板１が装着される。従って、該ケース挿入部２ｃの端部は振動板の外径に対応したガイド部を兼ねた構造となっており、ケース挿入部２ｃの端部は所定寸法の段部および、直径２．４ｍｍの口径を設け、更に該口径の一方は円錐面に拡げられ、最終的に直径５．４ｍｍの口径となり設け、図のようにホーン構造をした音道を設けてある。
【００２３】
以下、各部材の組み立て方法を説明する。振動板１を図７のごとく振動板ケース２に設置し、さらに、ケース挿入部２ｃにフォルダケース４の振動板押え部４ａを挿入し、所定の圧力で圧定し、図８のごとく相互の繋ぎ部に接着剤１１を塗布し、そのままの状態を保持し、振動板１装着済みの振動板ケース２をフォルダケース４に接着した。
【００２４】
また、フォルダ３には図３のように窓部３ｄよりファイバ先端保持孔３ｃ、３ｃ先端部近傍にファイバ固定用接着剤９（図５に示す）を塗布した後、ファイバ通し孔３ｂより２本の光ファイバ５、６を入れ、更に光ファイバ５、６夫々の先端部を各々のファイバ先端部保持孔３ｃ、３ｃに挿入し、更に押し込むと、光ファイバ先端部５ａ、６ａは、図５（ｂ）に示すようにファイバ先端部保持孔３ｃ、３ｃ頂部より出るが、この時点で、光ファイバ５、６頂部にも接着剤９を塗布し、光ファイバ５、６を前後に若干移動させると、光ファイバ５、６の周囲に付着した接着剤９がファイバ先端部保持孔３ｃ、３ｃに引き込まれ、該ファイバ先端部保持孔３ｃ、３ｃに存在する光ファイバ５、６の外周部および該ファイバ先端部保持孔３ｃ、３ｃ内の壁部を充満する。この充填状態で尚且つ図５（ｂ）に示すように２本の光ファイバ５、６の先端部５ａ、６ａが、ファイバ先端部保持孔３ｃ、３ｃより出た状態で、光ファイバ５、６先端部近傍、および窓部３ｄのファイバ先端保持孔下端部近傍に塗布されたファイバ固定用接着剤９を熱処理、或いはＵＶ光照射等にて硬化せしめた。
【００２５】
接着剤９硬化後のフォルダ３、すなわち光ファイバ５、６装着済みフォルダ３の先端部をフェルール先端研磨機に装着し、図５（ｃ）に示すようにフォルダ先端部を研磨したところ良好なファイバ先端部の研磨面３ｈを得た。そして、精度よく所定間隔に光ファイバ５、６をフォルダ３に極めて強固に装着した状態を得ることができた。図６（ａ）に示す研磨後のフォルダ３における２本の光ファイバ５、６を図６（ｂ）に示すように一本のチューブ７に納め、更に図６（ｃ）に示すようにファイバ通し孔３ｂに接着剤１０を充填し、フォルダ３右端部にファイバ曲がり防止用のゴム製のスリーブ８を装着した。
【００２６】
上記ファイバ装着済みフォルダ３の図６で示す底部３ｇを冶具に固定し、更に、図８に示すように前記振動板１装着済みフォルダケース４の右方からフォルダ３のファイバフォルダ部３ｆを挿入すると、フォルダケース４のねじ部４ｂの右端部およびフォルダ３のねじ部３ａの先端部が接触するので、図９に示すように振動板ケース２を軸中心回り回転させねじ込む。所定量ねじ込むと、ケースガイド部３ｅがフォルダケース４内面に接触し、更にねじ込んで行くと、相互の面がガイドされ、嵌め合い寸法範囲内で光ファイバ５、６先端部は振動板１の反射面に対して位置決めされる。
【００２７】
更に、所定の寸法量をねじ込んだ後、フォルダ３の端部より外側に延びた光ファイバ５、６の端部を夫々発光素子、および受光素子のコネクタに接続し、発光および受光をさせると共に、受光素子からの信号を受信可能にし、この信号の出力を計測可能な状態を得た後、振動板に所定の音圧を加え、この音圧により振動板が振動し、振動板反射面からの光が受光素子に投入された信号波形を確認しながら更に振動板ケース２を前記同様に回転させ、最も振動波形が大きい箇所にてねじ込みを止め、フォルダケースのねじ部４ｂの端部およびフォルダ３のねじ部３ａの一部に接着剤１１（図１に図示）を塗布てし、硬化せしめ、ねじロックをし、相互を装着せしめ完成となる。本実施例の場合、前記のごとく、ねじ込みにて位置決めを行った。
【００２８】
図１０に本発明の第２の実施例を示す。この例では光ファイバ５、６を固定するフォルダとしてフェルール１２が用いられ、振動板１は振動板ケース２と振動板固定具１３の夫々のねじ部２ａ、１３ａにより締着されている。フェルール１２はフェルールホルダ１４に固定され、また、振動板固定具１３にガイドされて直進スライド可能となっている。
【００２９】
フェルールホルダ１４を介してフェルール１２を保持するフェルールホルダ固定具１５のねじ部１５ａは振動板固定具１３のねじ部１３ｂと螺合し、フェルールホルダ１４は光ファイバ５、６の固定されたフェルール１２を振動板１に対して直進スライドさせる。このようにフェルール１２と振動板１に適度なクリアランスを設けてへリコイド機構などで直進スライドさせ、振動波形が大きい箇所にて接着剤等で固定し、フェルールホルダ１４の端部をカバー１６で覆う。
【００３０】
上記実施例の完成品の場合、実用上差支えない信号レベルを得ることができた。また、ファイバ先端部および振動板との距離も、約１．５ｍｍ〜２ｍｍと従来例より１５０倍〜２００倍の距離をとることができたし、更にまた、前記実施例以外にフォルダに光通信用フェルールを用いて次のような実施例の変形例のようなファイバ固定方法、およびファイバ間隔位置、および先端研磨を行ったが、前記と同様、実用上差支えない信号レベルを得ることができ、ファイバ先端部および振動板との距離も、上記同様に約１．５ｍｍ〜２ｍｍの距離をとることが可能であった。
【００３１】
以下、実施例の変形例におけるフェルール装着の状態を説明する。基本的は前記フォルダの装着と同様でフェルールに設けてあるファイバ用孔に光ファイバを通し、更にファイバ挿入後の該孔に接着剤を充填し、接着剤を硬化し、ファイバをフェルールに固着せしめた後、フェルール先端部を研磨し、光ファイバ先端部が完成される。設計目的、或いは用途によって光ファイバの配置、および研磨形状等を自由に選ぶことが可能である。図１１（ａ）〜（ｈ）は光ファイバの配置を示す各種先端部の正面図である。
【００３２】
図１１（ａ）〜（ｄ）に示すものはフェルール１２が角状であり、図１１（ｅ）〜（ｈ）に示すものはフェルール１２が円筒形状である。また、図１１（ａ）（ｂ）（ｅ）および（ｆ）に示すものは光ファイバ５と６の径が異なり、図１１（ｃ）（ｄ）（ｇ）および（ｈ）に示すものは光ファイバ５と６の径が同じである。
【００３３】
さらに、図１１（ａ）（ｃ）（ｅ）および（ｇ）に示すものは光ファイバ５と６がフェルール１２の別々の孔に封入され、図１１（ｂ）（ｄ）（ｆ）および（ｈ）に示すものは光ファイバ５と６がフェルール１２の同一の孔に封入されている。
【００３４】
また、フェルール先端の研磨状態を図１２に示すように平面研磨とする以外にも光学的性能を考慮して、図１３〜１５のような各種の研磨面を選ぶことが可能である。図１３はフェルール１２先端を球面に研磨した状態を示し、図１４はフェルール１２先端を円錐面に研磨した状態を示し、図１５はフェルール１２の投光側の面を斜めとして、受光側の面を平面とした例を示しているが、目的に応じ反対にしても一向に構わない。また、先端形状を示す図１２〜１５は図１１（ｇ）のフェルールに於けるファイバ配置の一例により示しているが、各種先端面形状において前記ファイバ配置の全てを組み合わせることが可能であることは勿論のところである。
【００３５】
本実施例の場合、前記のごとく耐熱フィルムを熱圧成型したが、受圧面と反射面を有する変位体が変位部の厚さが５０ミクロン以下の薄膜であれば、材質は目的に選べばよいいことは勿論である。また、反射面側も反射面でない側も共に一体表裏の受圧面であることで、種々の特徴ある機能、例えば、双指向性等の機能を有することが可能で、更に、変位体の振動共振周波数を低く設定する、例えば、２０Ｈｚ前後にした変位体を作製することにより、風圧によって変位する変位体等を制作することも可能で、この変位体は炎の動き等を検知するセンサー機能を有するものである。
【００３６】
或いは、構造を工夫することにより、変位体表裏にかる圧力が水圧であってもよく、更に、反射面を有する変位体を固定した筐体側からの振動を検出することも可能で、外部振動が筐体を介し変位体に伝えら、該変位体が前記外部振動に変位する振動体ならしめることにより、水中での振動を検出することも可能で、更に、筐体を所望の物体に固定することにより、固定した物体の振動を検出することも可能である。また、本発明における棒状導光路は単に光ファイバと記したが、この光ファイバとは世間一般に多用されているガラス、または光透過性樹脂等からなる光ファイバである。また、棒状導光路として半径方向に連続的に屈折率分布をもつことでレンズ作用を有するガラス細棒を受発光端として使うことによりさらに検出効率を高めることも可能であることは勿論である。
【００３７】
本発明の場合、変位体に設けられたドーム状反射面の光学有効面が球面であったが、使用目的に応じて、該ドーム形状を変えてよいことは勿論のことで、例えば、蒲鉾形状を用いても構わないし、更に、ドーム状反射面の光学有効面が非球面の２次曲面あっても、−向に構わないものである。
【００３８】
本変位検出装置は、気体、液体または固体を伝わる振動を伝えられた変位部にドーム形状反射面を設けたことで、その集光効果により、製造が容易な光拡散の中心軸が平行な導光路の光でも効率よく利用することが可能となり、簡易な装置構造で、従来の平面状の振動板を用いた検出装置よりも、更に高感度の検出装置を実現することが可能となった。
【００３９】
【発明の効果】
この発明の光電式変位検出装置によれば、変位体と光ファイバ先端部とのクリアランスを従来例のものより大幅に広げて設計しても、性能劣化が無い利点を有する。従って、環境変化の大きい状況下において、例えば、湿度が多く、尚且つ温度変化が大きい環境下等に於ける結露等の現象に対しても、露結水分が導光路端と反射面とにブリッジして自由な変位が妨げられることがなく、正常な変位の振幅を得ることが可能となり、検出装置の機能を維持発揮できるという効果を奏する。
【００４０】
また、本発明の変位検出装置は、既に世間一般に多用されて、広く頒布している光学用フェルールを流用できることで、安価な装置で生産実現が可能であるともに、用途に応じた脱着式の構造も、極めて容易に提供可能となる利点を有する。発光部および、受光部に於ける導光路先端径のバリエーションの効果は発光および受光端と反射ドームの反射面との間の距離と、導光路と反射ドームの光学的光軸とがなす正弦値の大きさを適宜選ぶことにより収束光の太さを調節できて、適切な変位検出の感度を設定できるものである。
【００４１】
フェルール先端の研磨状態を平面研磨、球面研磨以外、光ファイバなど導光路端部の断面が２次曲線となる非球面研磨等を選択することが可能で、これにより変位体に設けられた反射面の形状の選択と相俟って、検出対象の変位量の検出範囲と目的に合わせて、最適な信号変換を可能ならしめることにより、より一層高性能な検出感度を有した検出装置ができる利点を有する。
【００４２】
また、反射面については非球面を採用することで受光部に集光する光束の収差を押さえ込み、収束光を細くして変位検出の感度を高めることに寄与するものであり、検出すべき範囲により適切な反射面が選ばれる利点を有する。従って、これらの発明の各部の構成を目的に応じて組み合わせることにより、生産性、および保守性に優れ、しかも従来例より優れた性能の光電式変位検出装置を提供可能な利点を有する。
【図面の簡単な説明】
【図１】図１（ａ）は本発明の第１の実施例である光電式変位検出装置を示す断面図、図１（ｂ）は同光電式変位検出装置を示す正面図である。
【図２】同光電式変位検出装置の組立て状態を説明するための断面図である。
【図３】同光電式変位検出装置の組立て状態を説明するための断面図である。
【図４】図４（ａ）は同光電式変位検出装置の部材を示す平面図、図４（ｂ）は同部材を示す正面図、図４（ｃ）は図４（ｂ）におけるＡ−Ａ断面図である。
【図５】図５（ａ）は同光電式変位検出装置の一部組立て状態を示す断面図、図５（ｂ）および図５（ｃ）は同部分の加工状態を示す拡大断面図である。
【図６】同光電式変位検出装置の一部組立て状態を示す断面図である。
【図７】同光電式変位検出装置の組立て状態を説明するための断面図である。
【図８】同光電式変位検出装置の組立て状態を説明するための断面図である。
【図９】同光電式変位検出装置の組立て状態を説明するための断面図である。
【図１０】本発明の第２の実施例である光電式変位検出装置を示す断面図である。
【図１１】各実施例の変形例における光ファイバ端面を示す正面図である。
【図１２】図１２（ａ）は各実施例の変形例における光ファイバ端面部を示す正面図、図１２（ｂ）は同光ファイバ端面部を示す側面図、図１２（ｃ）は同光ファイバ端面部を示す斜視図である。
【図１３】図１３（ａ）は各実施例の他の変形例における光ファイバ端面部を示す正面図、図１３（ｂ）は同光ファイバ端面部を示す側面図、図１３（ｃ）は同光ファイバ端面部を示す斜視図である。
【図１４】図１４（ａ）は各実施例のさらに他の変形例における光ファイバ端面部を示す正面図、図１４（ｂ）は同光ファイバ端面部を示す側面図、図１４（ｃ）は同光ファイバ端面部を示す斜視図である。
【図１５】図１５（ａ）は各実施例のさらに他の変形例における光ファイバ端面部を示す正面図、図１５（ｂ）は同光ファイバ端面部を示す側面図、図１５（ｃ）は同光ファイバ端面部を示す斜視図である。
【図１６】従来の例を示す断面図である。
【図１７】従来の他の例を示す断面図である。
【符号の説明】
１振動板
２振動板ケース、２ａねじ部、２ｃケース挿入部
３フォルダ、３ａねじ部、３ｂファイバ通し穴、３ｃファイバ先端部
保持孔、３ｄ窓部、３ｅケースガイド部、３ｆアァイバフォルダ部
３ｇ底部、３ｈ研磨面
４フォルダケース、４ａ振動板押え部、４ｂねじ部
５光ファイバ、５ａ先端部
６光ファイバ、６ａ先端部
７チューブ
８スリーブ
９、１０、１１接着剤
１２フェルール
１３振動板固定具、１３ａ、１３ｂねじ部
１４フェルールフォルダ
１５フェルールフォルダ固定具、１５ａねじ部
１６カバー
１００測定媒体面
１０１、１０２光ファイバ、１０１ａ、１０２ａ端面
１０３、保持部、１０３ａ、１０３ｂ貫通穴
１０４接合面
１１０膜
１１１光ガイド、１１１ａ最上面、１１１ｂ上側面
１１２光ガイド、１１２ａ最上面、１１２ｂ上側面
１１３不透明部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a photoelectric displacement detection device for observing movement or vibration of a gas, a liquid or a solid, and particularly relates to a reflection surface of a displacement portion that comes into contact with an observation target and a medium in an optical detection portion, and transmission to a light source and a light receiving element. The present invention relates to a support for a rod-shaped light guide and a structure of a housing.
[0002]
[Prior art]
FIG. 16 shows a configuration of an optical acousto-electric signal conversion device disclosed in Japanese Patent Application Laid-Open No. 2000-88520 as an example of a conventional photoelectric displacement detection device put into practical use. As shown in FIG. 16, a planar measurement medium surface 100 is used, and a surface on the side opposite to the sound receiving side of the planar measurement medium surface 100 is used as a light reflecting surface. As shown in FIG. Light emitted from a light emitting element such as a light emitting diode enters from one end face of the optical fiber 101 on the light emitting side, further passes through the inside of the optical fiber 101, is emitted from the other end face 101a, and is emitted from the measurement medium surface 100a. Is projected on a predetermined portion of the reflecting surface, ie, substantially at the center.
[0003]
The projected light is reflected by the reflection surface of the measurement medium surface 100, reaches the end surface 102a of the optical fiber 102 on the light receiving side, enters the light from the end surface 102a, further passes through the optical fiber 102, and The light is emitted from the end face and is projected on a predetermined face of the light receiving element. The end face 101a of the optical fiber 101 on the light emitting side and the end face 102a of the optical fiber 102 on the light receiving side, which are provided on the reflection surface side of the measurement medium surface 100, are set at a predetermined angle θ with respect to the optical axis of the optical fiber. Further, the optical fiber 101 and the optical fiber 102 are inserted into the through holes 103a and 103b of the holder 103 so that the optical axis of the optical fiber 101 and the optical axis of the optical fiber 102 form a predetermined angle α. It is held to be joined. In addition, the clearance between the end faces of the optical fibers 101 and 102 and the measurement medium surface 100 is set to a predetermined size and mounted.
[0004]
FIG. 17 shows a configuration of an optical acousto-electric signal converter disclosed in JP-A-2002-186099. As shown in FIG. 17, this optical acousto-electric signal conversion device has a light guide 111 on the light projecting side and a light guide 112 on the light receiving side adjacent to each other in parallel via an opaque portion 113, and the optical axis of each optical fiber. The uppermost surfaces 111a and 112a, which are perpendicular to the optical fiber 111 and 112a, maintain a desired clearance with respect to the reflecting surface of the planar film 110, and further, the optical fibers are arranged vertically, and the distal ends (most Not only the upper surfaces 111a and 112a) but also the side surfaces (upper surfaces 111b and 112b) are polished at an angle of 15 ° with respect to the optical axis to detect the displacement of the film 110. In the example, there are significant disadvantages:
[0005]
Hereinafter, the disadvantages of the conventional example will be described. In the conventional example, two optical fibers are arranged at a predetermined angle, the ends of the optical fibers are made adjacent to each other, and the light emitting surface and the light receiving surface at the ends are reflected. It is well known that processing must be performed to have a predetermined angle and flatness with respect to the surface, which significantly increases the number of steps and the processing accuracy.
[0006]
In addition, when processing the fiber tip portion in advance, the number of processing steps is further increased, and it is difficult to obtain the processing accuracy. Of course, even if the processing accuracy is obtained, variations occur even when the fiber is mounted symmetrically. Is a matter of course.
[0007]
From the above, the above-described conventional example has a structure that is not suitable for mass production, requires the introduction of dedicated machine equipment and the like in order to respond to mass production, and further, in order to maintain the accuracy, Improvement of work skill is an essential condition. Therefore, it is difficult to maintain the prescribed quality unless training, training, and the like are performed for the workers. In other words, it is obvious that skilled workers are always necessary, and when performing industrial production on the premise of mass production, this is a significant obstacle.
[0008]
Further, in the conventional example, since the tip of the optical fiber with a certain degree of accuracy is installed so as to face the diaphragm reflecting surface and has a planar diaphragm, the reflecting surface is necessarily flat. There is a structure in which light is projected and received on the flat reflecting surface, and the displacement of the diaphragm is detected. Therefore, in order to obtain a practical sensitivity, it is preferable that the clearance between the reflecting surface and the fiber tip portion is as narrow as possible on the optical structure. It is well known that it must be installed.
[0009]
Therefore, with the current clearance in the conventional example, phenomena such as dew condensation frequently occur in a situation where the environment changes greatly, for example, in an environment where the humidity is high and the temperature changes greatly. In such a case, there is an extremely serious drawback such as a fatal situation as a function of the detection device that water enters as a lump into the gap between the diaphragm and the optical fiber, which interferes with the amplitude of the diaphragm. are doing.
[0010]
[Patent Document 1]
JP-A-2000-88520 (pages 2, 3; FIG. 2)
[0011]
[Patent Document 2]
JP-A-2002-186099 (page 3, FIG. 2)
[0012]
[Problems to be solved by the invention]
In the case of manufacturing an optical acousto-electric signal converter as in the above-mentioned conventional example, the light emitting optical fiber and the light receiving optical fiber have a fixed angle, and the tip of each optical fiber is kept at a fixed angle. It is necessary to polish the end face while further fixing the diaphragm so that the diaphragm is located at the intersection of the extension lines of the optical fiber center lines so as to be perpendicular to the mounting center line of the pair of optical fibers. There is. These methods require not only the polishing process but also the assembling process, because a predetermined accuracy is required, a dedicated adjusting device and a skilled work are required, and the man-hour in the adjusting process is increased, and the production time is increased. This was a major cost increase factor. Further, the clearance between the diaphragm and the tip of the pair of optical fibers in the conventional example may cause a fatal situation as a function of the optical acousto-electric signal conversion device under a situation where the environmental change is large. Has a very serious disadvantage.
[0013]
Furthermore, in the case of a conventional optical acousto-electric signal converter having a planar reflecting surface, it is natural that the light emitted from the light projecting fiber is reflected by the reflecting surface and received by the light receiving fiber. However, no light-collecting effect is obtained. Therefore, it is clear that the structure cannot be denied that the optical efficiency is limited.
[0014]
The present invention has been made in view of the above-described drawbacks of the conventional example, and has as its object to simplify the adjustment mechanism, to reduce the number of adjustment steps, to achieve mass production, and Has a structure that can increase the clearance between the reflective surface that is displaced and the front end of the light guide path that faces it, and further improves optical efficiency, resulting in high reliability and stable quality. An object of the present invention is to provide a photoelectric displacement detection device for detecting changes in sound pressure, wind pressure, water pressure, vibration, and the like.
[0015]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the photoelectric displacement detection device of the present invention is configured such that a part of the displacement portion is formed in a dome shape, and the inner surface of the dome is used as a reflection surface to provide a light-collecting effect, thereby providing a pair of projection devices. Even if the fixed angles of the light and light receiving rod-shaped light guides are arranged in parallel, there is basically no problem with the structure, and furthermore, the clearance between the tip of the pair of dedicated light guides and the reflecting surface of the displacement portion is greatly increased. The structure is acceptable.
[0016]
In addition, a folder for fixing the dedicated light guide is provided, and holes are provided in the folder at predetermined intervals in which the rod-shaped light guides can be arranged in parallel, or holes are provided in which two rod-shaped light guides collectively enter in parallel. After the fibers are bonded and fixed, a structure for polishing the light emitting and receiving end portions together with the folder and a manufacturing method are adopted, and a ferrule is used as the folder according to the design purpose.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
A first embodiment of the present invention will be described below with reference to the drawings, in which an optical fiber is used as a rod-shaped light guide and sound pressure is detected. As shown in the cross-sectional view of FIG. 1, in the case of the present embodiment using the folder 3, the folder case 4, and the displacement body, the displacement body is hereinafter referred to as a diaphragm 1 in order to detect sound pressure. The diaphragm 1, the diaphragm case 2, and the optical fibers 5 and 6 are configured. It should be noted that the light emitting element and the light receiving element mounted on the other ends of the optical fibers 5 and 6 mounted on the folder 3, the arrangement structure of the elements, the electric circuit for driving the elements, and the like are omitted. .
[0018]
In this embodiment, the folder 3 and the folder case 4 are made of aluminum. However, the folder 3 may be made of ceramic or plastic. The diaphragm 1 is obtained by subjecting a heat-resistant film to hot-pressure molding, and performing metal deposition and surface treatment on the inner surface of the formed dome to obtain a predetermined reflectance and a desired surface roughness. Hereinafter, the details of the folder 3 will be described. The folder 3 is substantially rod-shaped and has a shape as shown in the cross-sectional view of FIG. 4, a length of 18 mm, a maximum thickness of a bottom 3 g shown in the figure at a bottom 6.6 mm, and a length of 5. 6 mm. 1 mm.
[0019]
Further, a thread 3a (M5 fine) is provided on the left side of the bottom 3g, and the length of the thread 3a is about 6 mm. A case guide portion 3e having a diameter of 4 mm and a length of 3.8 mm is provided on the left side of the screw portion 3a, and a fiber folder portion 3f having a diameter of 1.55 mm and a length of 2.4 mm is provided thereon. Have been. Two holes having a diameter of 0.26 mm (hereinafter, referred to as fiber tip holding holes 3c) are provided in the fiber folder portion 3f at a position of 0.35 mm at the center distribution and vertically toward the left. In addition, a hole having a diameter of 6.6 mm and a depth of 14.9 mm (hereinafter, referred to as a fiber through hole 3b) was also provided from the right end to the left end of the folder.
[0020]
Therefore, the two fiber tip holding holes 3c are connected to the fiber through holes 3b as shown in the figure, and the length of the fiber tip holding hole 3c is about 2.8 mm. Further, as shown in the plan view of FIG. 4 (a) and the front view of FIG. 4 (b), the fiber folder 3f and the case guide 3e are left at a distance of 1.2 mm from the tip of the fiber folder 3f. A cutting process is performed with a length of 5.9 mm toward the direction. Accordingly, as shown in the cross-sectional view of FIG. 4C, the through hole 3b of the fiber is exposed, and a window 3d penetrating the case guide 3e is provided on the right side of the fiber holder 3f.
[0021]
Hereinafter, the details of the folder case 4 will be described. It is generally cylindrical and has a shape as shown in the cross-sectional view of FIG. 2, a length of 14 mm, a maximum thickness of 6.6 mm in almost the entire area shown in the figure, and a left diaphragm pressing portion 4 a. Are dimensions to be attached to the diaphragm case 2, and have a diameter of 6 mm and a length of 2.2 mm. Further, a screw portion 4b (M5 fine) is provided upward from the lower end portion. The length of the screw portion 4b is about 6.2 mm, and the length corresponding to the folder 3 is further increased. The other is an inner surface of a folder case having a diameter of 4 mm, and the case guide portion 3e of the folder is fitted and inserted into this portion, so that the size of this portion is a fitting dimension.
[0022]
Hereinafter, the details of the diaphragm case 2 will be described. The cap 1 has a substantially cylindrical shape, as shown in the cross-sectional view of FIG. 2, a length of 6.2 mm, a maximum thickness of 6.6 mm over the entire area shown in the figure, and a right side of the diaphragm 1. It has dimensions corresponding to the mounting, and has a diameter of 6 mm and a length of the portion (hereinafter referred to as case insertion portion 2c) of 2 mm. Since the diaphragm holding portion 4a of the folder case 4 is inserted into the case insertion portion 2c, the size of the portion is a fitting size. Further, the diaphragm 1 is mounted on the left end of the case insertion portion 2c in the drawing. Therefore, the end of the case insertion portion 2c has a structure also serving as a guide portion corresponding to the outer diameter of the diaphragm, and the end of the case insertion portion 2c has a step of a predetermined size and a diameter of 2.4 mm. An aperture is provided, and one of the apertures is expanded into a conical surface, and finally has an aperture having a diameter of 5.4 mm, and a sound path having a horn structure as shown in the figure is provided.
[0023]
Hereinafter, a method of assembling each member will be described. The diaphragm 1 is installed in the diaphragm case 2 as shown in FIG. 7, and furthermore, the diaphragm holding portion 4a of the folder case 4 is inserted into the case insertion portion 2c, and the pressure is fixed at a predetermined pressure. An adhesive 11 was applied to the connecting portion, the state was maintained as it was, and the diaphragm case 2 with the diaphragm 1 attached was bonded to the folder case 4.
[0024]
Also, as shown in FIG. 3, a fiber fixing adhesive 9 (shown in FIG. 5) is applied to the folder 3 from the window 3d to the vicinity of the fiber tip holding holes 3c and 3c from the window 3d. When the optical fibers 5 and 6 are inserted, and the distal ends of the optical fibers 5 and 6 are further inserted into the respective fiber distal end holding holes 3c and 3c, and further pushed in, the optical fiber distal ends 5a and 6a become the optical fibers 5 and 6 shown in FIG. As shown in b), the adhesive exits from the tops of the fiber tip holding holes 3c and 3c. At this point, the adhesive 9 is applied to the tops of the optical fibers 5 and 6 and the optical fibers 5 and 6 are slightly moved back and forth. The adhesive 9 attached around the optical fibers 5 and 6 is drawn into the fiber tip holding holes 3c and 3c, and the outer peripheral portions of the optical fibers 5 and 6 existing in the fiber tip holding holes 3c and 3c and the fiber Tip holding holes 3c, 3c To fill the wall. In this filled state, as shown in FIG. 5 (b), with the tips 5a, 6a of the two optical fibers 5, 6 coming out of the fiber tip holding holes 3c, 3c, the optical fibers 5, 6 The fiber fixing adhesive 9 applied near the distal end and near the lower end of the fiber distal end holding hole in the window 3d was cured by heat treatment or UV light irradiation.
[0025]
The folder 3 after the adhesive 9 was cured, that is, the tip of the folder 3 with the optical fibers 5 and 6 attached was mounted on a ferrule tip polishing machine, and the folder tip was polished as shown in FIG. A polished surface 3h at the tip was obtained. Then, it was possible to obtain a state in which the optical fibers 5 and 6 were extremely firmly attached to the folder 3 at predetermined intervals with high accuracy. The two optical fibers 5, 6 in the polished folder 3 shown in FIG. 6 (a) are placed in one tube 7 as shown in FIG. 6 (b), and further, as shown in FIG. 6 (c). The through hole 3b was filled with the adhesive 10, and a rubber sleeve 8 for preventing fiber bending was attached to the right end of the folder 3.
[0026]
6 is fixed to a jig, and as shown in FIG. 8, the fiber folder 3f of the folder 3 is inserted from the right side of the folder case 4 with the diaphragm 1 mounted thereon. Since the right end of the threaded portion 4b of the folder case 4 and the tip of the threaded portion 3a of the folder 3 come into contact with each other, the diaphragm case 2 is rotated around the axis and screwed in as shown in FIG. When the screw is screwed in a predetermined amount, the case guide portion 3e comes into contact with the inner surface of the folder case 4, and when the screw screw is further screwed, the mutual surfaces are guided, and the distal ends of the optical fibers 5 and 6 reflect the diaphragm 1 within the fitting dimension range. Positioned relative to the plane.
[0027]
Furthermore, after screwing a predetermined amount of dimensions, the ends of the optical fibers 5 and 6 extending outside from the ends of the folder 3 are connected to the connectors of the light emitting element and the light receiving element, respectively, to emit light and receive light. After receiving a signal from the light receiving element and obtaining a state in which the output of this signal can be measured, a predetermined sound pressure is applied to the diaphragm, and the diaphragm vibrates due to the sound pressure, and the diaphragm reflects from the reflecting surface. The diaphragm case 2 is further rotated in the same manner as described above while confirming the signal waveform in which the light is applied to the light receiving element, and the screwing is stopped at the position where the vibration waveform is the largest, and the end of the screw portion 4b of the folder case and the folder 3 are stopped. An adhesive 11 (shown in FIG. 1) is applied to a part of the threaded portion 3a, and is hardened, screw-locked, and attached to each other to complete the process. In the case of the present embodiment, positioning was performed by screwing in as described above.
[0028]
FIG. 10 shows a second embodiment of the present invention. In this example, a ferrule 12 is used as a folder for fixing the optical fibers 5 and 6, and the diaphragm 1 is fastened by screw portions 2a and 13a of a diaphragm case 2 and a diaphragm fixing member 13, respectively. The ferrule 12 is fixed to a ferrule holder 14 and is guided by a diaphragm fixture 13 so as to be able to slide straight.
[0029]
The screw part 15a of the ferrule holder fixture 15 for holding the ferrule 12 via the ferrule holder 14 is screwed with the thread part 13b of the diaphragm fixture 13, and the ferrule holder 14 is the ferrule 12 to which the optical fibers 5 and 6 are fixed. Slides straight against the diaphragm 1. In this way, the ferrule 12 and the diaphragm 1 are provided with an appropriate clearance and are slid straight by a helicoid mechanism or the like, and are fixed at a portion where the vibration waveform is large with an adhesive or the like, and the end of the ferrule holder 14 is covered with the cover 16. .
[0030]
In the case of the finished product of the above embodiment, a signal level which does not hinder practical use could be obtained. In addition, the distance between the fiber tip and the diaphragm was about 1.5 mm to 2 mm, which was 150 to 200 times the distance of the conventional example. A fiber fixing method such as the following modification of the embodiment using the ferrule, and the fiber spacing position, and the tip polishing was performed, but as described above, it is possible to obtain a practically acceptable signal level, The distance between the fiber tip and the diaphragm could be about 1.5 mm to 2 mm as described above.
[0031]
Hereinafter, a state in which a ferrule is mounted in a modified example of the embodiment will be described. Basically, the optical fiber is passed through the fiber hole provided in the ferrule in the same manner as the mounting of the folder, and the hole after filling the fiber is filled with an adhesive, the adhesive is cured, and the fiber is fixed to the ferrule. After that, the tip of the ferrule is polished to complete the tip of the optical fiber. The arrangement of the optical fibers, the polished shape, and the like can be freely selected depending on the design purpose or application. 11 (a) to 11 (h) are front views of various tips showing the arrangement of optical fibers.
[0032]
11 (a) to 11 (d), the ferrule 12 has a square shape, and those shown in FIGS. 11 (e) to 11 (h), the ferrule 12 has a cylindrical shape. 11 (a), (b), (e) and (f) have different diameters of the optical fibers 5 and 6, while those shown in FIGS. 11 (c), (d), (g) and (h) The optical fibers 5 and 6 have the same diameter.
[0033]
11 (a), (c), (e) and (g) show that the optical fibers 5 and 6 are sealed in separate holes of the ferrule 12, and that the optical fibers 5 and 6 are shown in FIGS. 11 (b), (d), (f) and (g). 1h, the optical fibers 5 and 6 are sealed in the same hole of the ferrule 12.
[0034]
In addition to the flat polishing as shown in FIG. 12, the polished state of the ferrule tip can be selected from various polishing surfaces as shown in FIGS. 13 shows a state in which the tip of the ferrule 12 is polished to a spherical surface, FIG. 14 shows a state in which the tip of the ferrule 12 is polished to a conical surface, and FIG. Is shown as a plane, but may be reversed depending on the purpose. 12 to 15 showing the tip shapes are shown by way of example of the fiber arrangement in the ferrule of FIG. 11 (g). However, it is possible to combine all of the fiber arrangements in various end face shapes. Of course.
[0035]
In the case of this embodiment, the heat-resistant film was formed by hot-pressing as described above, but if the displacement body having the pressure-receiving surface and the reflection surface is a thin film having a displacement portion having a thickness of 50 μm or less, the material may be selected for the purpose. Of course, it is good. Further, since both the reflection surface side and the non-reflection surface are integrally pressure receiving surfaces on the front and back sides, it is possible to have various characteristic functions, for example, a function such as bi-directionality, and further, the vibration resonance of the displacement body. By setting a low frequency, for example, by manufacturing a displacement body at about 20 Hz, it is also possible to produce a displacement body or the like that is displaced by wind pressure, and this displacement body has a sensor function of detecting a movement of a flame or the like. Things.
[0036]
Alternatively, by devising the structure, the pressure applied to the front and back of the displacement body may be water pressure, and further, it is possible to detect the vibration from the housing side to which the displacement body having the reflecting surface is fixed, and the external vibration can be detected. By transmitting the vibration to the displacement body via the casing and displacing the displacement body into the external vibration, vibration in water can be detected, and further, the casing is fixed to a desired object. This makes it possible to detect the vibration of the fixed object. Further, the rod-shaped light guide in the present invention is simply described as an optical fiber, but this optical fiber is an optical fiber made of glass, light-transmitting resin or the like which is widely used in the world. Further, it is a matter of course that the detection efficiency can be further increased by using a thin glass rod having a lens function as a rod-shaped light guide path having a refractive index distribution continuously in the radial direction as a light receiving / emitting end.
[0037]
In the case of the present invention, the optically effective surface of the dome-shaped reflecting surface provided on the displacement body is a spherical surface, but it is needless to say that the dome shape may be changed according to the purpose of use. May be used, and even if the optically effective surface of the dome-shaped reflecting surface is an aspherical quadratic curved surface, the negative direction is acceptable.
[0038]
This displacement detection device has a dome-shaped reflection surface at the displacement portion to which vibrations transmitted through a gas, liquid or solid are transmitted. Light from the optical path can be used efficiently, and a detection device with a simpler device structure and higher sensitivity than a conventional detection device using a planar diaphragm can be realized.
[0039]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to the photoelectric displacement detection apparatus of this invention, even if it designs the clearance between a displacement body and the front-end | tip part of an optical fiber significantly wider than the conventional example, there exists an advantage which does not have performance degradation. Therefore, in a situation where the environmental change is large, for example, in a case where the humidity is large and the temperature is largely changed, the dew condensation bridges between the light guide path end and the reflection surface. Thus, the free displacement is not hindered, and a normal displacement amplitude can be obtained, so that the function of the detection device can be maintained and exhibited.
[0040]
In addition, the displacement detection device of the present invention can be realized by using an inexpensive device by utilizing an optical ferrule widely used in the public and widely distributed, and a detachable structure according to the application. Also has the advantage that it can be provided very easily. The effect of the variation of the tip diameter of the light guide path in the light emitting unit and the light receiving unit is the distance between the light emitting and receiving end and the reflection surface of the reflection dome, and the sine value between the light guide path and the optical axis of the reflection dome. The thickness of the convergent light can be adjusted by appropriately selecting the size of, and the sensitivity of the displacement detection can be set appropriately.
[0041]
The polishing state of the ferrule tip can be selected from flat polishing and spherical polishing, as well as aspherical polishing where the cross section of the end of the light guide path such as an optical fiber has a quadratic curve. In addition to the selection of the shape, the optimal signal conversion can be performed in accordance with the detection range and the purpose of the displacement amount of the detection object, thereby providing a detection device with higher performance detection sensitivity. Having.
[0042]
In addition, by adopting an aspherical surface for the reflection surface, it suppresses the aberration of the light beam condensed on the light receiving unit, narrows the convergent light, and contributes to increase the sensitivity of displacement detection. This has the advantage that an appropriate reflecting surface is selected. Therefore, there is an advantage that by combining the configurations of the respective parts of the invention according to the purpose, it is possible to provide a photoelectric displacement detection device which is excellent in productivity and maintainability, and which has a performance superior to the conventional example.
[Brief description of the drawings]
FIG. 1A is a cross-sectional view illustrating a photoelectric displacement detection device according to a first embodiment of the present invention, and FIG. 1B is a front view illustrating the photoelectric displacement detection device.
FIG. 2 is a cross-sectional view for explaining an assembled state of the photoelectric displacement detection device.
FIG. 3 is a cross-sectional view for explaining an assembled state of the photoelectric displacement detection device.
4 (a) is a plan view showing members of the photoelectric displacement detection device, FIG. 4 (b) is a front view showing the same members, and FIG. It is A sectional drawing.
FIG. 5A is a cross-sectional view showing a partially assembled state of the photoelectric displacement detection device, and FIGS. 5B and 5C are enlarged cross-sectional views showing a processed state of the same part. .
FIG. 6 is a sectional view showing a partially assembled state of the photoelectric displacement detection device.
FIG. 7 is a cross-sectional view for explaining an assembled state of the photoelectric displacement detection device.
FIG. 8 is a cross-sectional view for explaining an assembled state of the photoelectric displacement detection device.
FIG. 9 is a cross-sectional view for explaining an assembled state of the photoelectric displacement detection device.
FIG. 10 is a sectional view showing a photoelectric displacement detection device according to a second embodiment of the present invention.
FIG. 11 is a front view showing an optical fiber end face in a modification of each embodiment.
FIG. 12A is a front view showing an end face of an optical fiber in a modification of each embodiment, FIG. 12B is a side view showing the end face of the optical fiber, and FIG. It is a perspective view which shows a fiber end surface part.
13 (a) is a front view showing an optical fiber end face in another modification of each embodiment, FIG. 13 (b) is a side view showing the same optical fiber end face, and FIG. 13 (c) is It is a perspective view which shows the optical fiber end surface part.
FIG. 14A is a front view showing an optical fiber end face in still another modified example of each embodiment, FIG. 14B is a side view showing the optical fiber end face, and FIG. 14C. FIG. 2 is a perspective view showing an end face of the optical fiber.
15 (a) is a front view showing an optical fiber end face in still another modification of each embodiment, FIG. 15 (b) is a side view showing the same optical fiber end face, and FIG. 15 (c). FIG. 2 is a perspective view showing an end face of the optical fiber.
FIG. 16 is a sectional view showing a conventional example.
FIG. 17 is a cross-sectional view showing another example of the related art.
[Explanation of symbols]
1 diaphragm
2 Diaphragm case, 2a screw part, 2c case insertion part
3 folder, 3a screw part, 3b fiber through hole, 3c fiber tip
Holding hole, 3d window, 3e case guide, 3f fiber folder
3g bottom, 3h polished surface
4 Folder case, 4a Diaphragm holding part, 4b Screw part
5 Optical fiber, 5a Tip
6 Optical fiber, 6a Tip
7 tubes
8 sleeve
9, 10, 11 adhesive
12 Ferrule
13 diaphragm fixing device, 13a, 13b screw part
14 Ferrule folder
15 Ferrule folder fixture, 15a screw
16 Cover
100 Measurement medium surface
101, 102 Optical fiber, 101a, 102a End face
103, holding portion, 103a, 103b through hole
104 joining surface
110 membrane
111 light guide, 111a top surface, 111b upper surface
112 light guide, 112a top surface, 112b upper surface
113 Opaque part

Claims

A light emitting unit and a light receiving unit are arranged at positions opposed to a reflecting surface of a displacement body having a pressure receiving surface and a reflecting surface, and the light emitting unit and the light receiving unit have a refractive index distribution from an axis to an outer periphery thereof. An end of a rod-shaped light guide path made of a conductive resin, radiating light from the light emitting portion to the displacement body reflection surface, receiving light reflected from the displacement body reflection surface by the light receiving portion, and displacing the displacement body. In the photoelectric displacement detection device, the reflection surface has a dome shape having a desired radius dimension, and the pair of rod-shaped light guide paths are aligned with each other at a desired interval with respect to the dome-shaped reflection surface. A photoelectric displacement detecting device, wherein a core is arranged in parallel, and the entire outer peripheral portion of the dedicated light guide path is fixed in a direction opposite to the reflection surface from a tip end thereof.

The folder has a folder for holding the dedicated light guide, holes are provided in the folder corresponding to the outer diameter of the rod-shaped light guide at predetermined intervals, the rod-shaped light guide is passed through the hole, and the dedicated light guide is passed through. An optical path or an outer peripheral portion and an inner wall portion of the folder hole are filled with an adhesive resin or the like, and the rod-shaped light guide path is bonded and fixed to the folder. Item 1. The photoelectric displacement detection device according to Item 1.

The folder has a folder for holding the dedicated light guide, and a hole corresponding to the outer diameter of the entire pair of rod-shaped light guides is provided in the folder. The rod-shaped light guide path is fixed to the folder by filling the outer periphery of the light path and the inner wall of the folder hole with an adhesive resin, and then, the tip of the rod-shaped light guide path is polished together with the folder. 1. The photoelectric displacement detection device of 1.

The photoelectric displacement detection device according to claim 2, wherein a material of the folder is ceramic, metal, or plastic.

The photoelectric displacement detecting device according to claim 2, wherein the folder is a ferrule for an optical fiber.

The photoelectric displacement detection device according to claim 1, wherein two rod-shaped light guide paths have different diameters in the pair of rod-shaped light guide paths.

The displacement body having the dome-shaped reflection surface and the pair of dedicated light guide paths are fixed to a housing, and the pair of rod-shaped light guide paths fixed to the housing or the displacement body having the dome-shaped reflection surface are provided in the housing. 2. The photoelectric displacement detecting device according to claim 1, wherein the photoelectric displacement detecting device has a structure which can be easily attached to and detached from the device.

2. The photoelectric conversion device according to claim 1, wherein the polished surface is a single surface and is flat, including an end surface of the light-emitting side and the light-receiving side rod-shaped light guide, and a folder or a ferrule to which the rod-shaped light guide is fixed. Displacement detector.

4. The polished surface is a continuous single surface and a spherical surface including the end surfaces of the light emitting side and light receiving side rod-shaped light guides and a folder or a ferrule to which the rod-shaped light guides are fixed. 2. The photoelectric displacement detection device according to 1.

4. The end surface of the light-emitting and light-receiving side rod-shaped light guides and the polished surface of the folder to which the rod-shaped light guides are fixed are continuous, continuous surfaces and are aspherical. Photoelectric displacement detector.

3. An end face of the light-emitting side and light-receiving side rod-shaped light guide and one of two polishing surfaces of a folder to which the rod-shaped light guide is fixed are polished at a desired angle. Or the photoelectric displacement detection device according to 3.

2. The photoelectric displacement detecting device according to claim 1, wherein the displacement body having the pressure receiving surface and the reflection surface is formed of a thin film having a thickness of 50 μm or less, and both the reflection surface side and the non-reflection surface are integrated pressure reception surfaces. .

8. A displacement plate having a dome-shaped reflection surface fixed to a housing in which the entire outer periphery of the dedicated light guide is fixed is a diaphragm that is displaced by sound pressure applied to the displacement member. Photoelectric displacement detector.

8. The diaphragm according to claim 7, wherein the displacement body having a dome-shaped reflection surface fixed to a housing in which the entire periphery of the dedicated light guide path is fixed is a diaphragm that is displaced by wind pressure applied to the displacement body. Photoelectric displacement detector.

8. The photoelectric device according to claim 7, wherein the displacement body having a dome-shaped reflection surface fixed to a housing in which the entire outer periphery of the rod-shaped light guide path is fixed is a diaphragm that is displaced by water pressure applied to the displacement body. Displacement detector.

The displacement body having a dome-shaped reflection surface fixed to a housing formed by fixing the entire outer periphery of the rod-shaped light guide path is a trembling body that is displaced by transmitting external vibration applied to the displacement body. The photoelectric displacement detection device according to claim 7.

The photoelectric displacement detection device according to claim 1, wherein the rod-shaped light guide path is a rod-shaped lens made of glass or light-transmitting resin having a refractive index distribution continuously in a radial direction.

The photoelectric displacement detecting device according to claim 1, wherein the rod-shaped light guide path is an optical fiber made of glass or light-transmitting resin.

The photoelectric displacement detection device according to claim 1, wherein an optically effective surface of the dome-shaped reflection surface provided on the displacement body is a spherical surface.

2. The photoelectric displacement detecting device according to claim 1, wherein the optically effective surface of the dome-shaped reflecting surface provided on the displacement body is an aspherical quadratic curved surface.