JP3673914B2

JP3673914B2 - Light scattering particle detector

Info

Publication number: JP3673914B2
Application number: JP2000335330A
Authority: JP
Inventors: 敬水上; 朋信松田; 憲司佐々木; 勉中島
Original assignee: Rion Co Ltd
Current assignee: Rion Co Ltd
Priority date: 2000-11-02
Filing date: 2000-11-02
Publication date: 2005-07-20
Anticipated expiration: 2020-11-02
Also published as: JP2002139415A

Description

【０００１】
【発明の属する技術分野】
本発明は、レーザ媒質を用いたレーザ発振器を光源として試料流体中に含まれる粒子を検出する光散乱式粒子検出器に関する。
【０００２】
【従来の技術】
従来の光散乱式粒子検出器としては、図８に示すように、レーザ発振器を構成するレーザ媒質１０５と反射鏡１０６の間に粒子検出対象となる流体により流路１０７を形成し、半導体レーザ１０８の励起用光Ｌｅを集光レンズ１０９でレーザ媒質１０５に集光させてレーザ媒質１０５を励起させ、レーザ媒質１０５と反射鏡１０６の間で共振するレーザ光Ｌａと流路１０７が交差する箇所を粒子検出領域１１０とし、共振するレーザ光Ｌａによって粒子検出領域１１０で発生する散乱光を受光部（不図示）で受光して散乱光の強度に応じた電気信号から試料流体中に含まれる粒子を検出するものが知られている。
【０００３】
なお、１１２は中空な第１取付ブロック、１１３は中空な第２取付ブロックであり、第１取付ブロック１１２と第２取付ブロック１１３でケース本体が形成される。レーザ媒質１０５は、第２取付ブロック１１３に直接組み付けられ、第２取付ブロック１１３は第１取付ブロック１１２に組み付けられる。また、受光部を収納した受光ケース（不図示）は第１取付ブロック１１２の側面に組み付けられる。
【０００４】
そして、レーザ媒質１０５を第２取付ブロック１１３に組み付けたとき、組付誤差等がなければ、レーザ媒質１０５が放射するレーザ光Ｌａは、レーザ媒質１０５の端面（放射面）に対して垂直方向で、且つ第１取付ブロック１１２の中心軸と一致する方向に進む。
【０００５】
【発明が解決しようとする課題】
しかし、実際には、組付誤差等があるため、レーザ光Ｌａは第１取付ブロック１１２の中心軸と一致する方向に出ていかない。この場合、反射鏡１０６の第１取付ブロック１１２に対する取付角度を調整することによって、反射鏡１０６で反射するレーザ光Ｌａが確実にレーザ媒質１０５に帰還するようにする必要がある。
【０００６】
更に、反射鏡１０６で反射するレーザ光Ｌａが確実にレーザ媒質１０５に帰還するように反射鏡１０６を最適な取付角度に調整したとしても、発振したレーザ光Ｌａの放射方向は第１取付ブロック１１２の中心軸と一致しないので、一致することを前提に配置した流路１０７をずらす必要性が生じる場合もある。そして、流路１０７をずらせば粒子検出領域１１０の位置も変化することになるので、これに応じて受光部を収納した受光ケースの第１取付ブロック１１２への取付位置も調整しなければならない。
【０００７】
従って、従来の光散乱式粒子検出器においては、組付誤差等がある場合に行う反射鏡１０６の取付角度調整に伴って、流路１０７の位置調整や受光ケースの第１取付ブロック１１２に対する取付調整などに複雑な調整を必要とすると共に、装置全体の組立作業時に多くの工数を必要とするため、問題となっていた。
【０００８】
本発明は、従来の技術が有するこのような問題点に鑑みてなされたものであり、その目的とするところは、レーザ媒質や反射鏡などの組付角度調整が容易な散乱式粒子検出器を提供しようとするものである。
【０００９】
【課題を解決するための手段】
上記課題を解決すべく請求項１に係る発明は、励起用光によって励起するレーザ媒質と、このレーザ媒質が放射するレーザ光を反射する反射鏡の間に、試料流体が形成する流路を配置し、この流路に前記レーザ光を照射して粒子検出領域を形成し、この粒子検出領域に含まれる粒子を前記レーザ光によって生じる散乱光を受光して検出する光散乱式粒子検出器において、前記レーザ媒質の取付ブロックに対する取付角度と前記反射鏡の取付ブロックに対する取付角度を調整する取付角度調整手段を設け、前記レーザ媒質の取付角度調整手段が、前記レーザ媒質の取付部材の縁部にねじを切ったねじ孔とねじを切っていない孔を交互に形成すると共に、前記レーザ媒質の取付ブロックに前記ねじを切っていない孔と中心軸が一致するねじ孔を形成し、前記取付部材のねじを切ったねじ孔へのボルトのねじ込み量と、前記取付部材のねじを切っていない孔へ挿通したボルトの前記取付ブロックへのねじ込み量を調整するものである。
【００１０】
請求項２に係る発明は、励起用光によって励起するレーザ媒質と、このレーザ媒質が放射するレーザ光を反射する反射鏡の間に、試料流体が形成する流路を配置し、この流路に前記レーザ光を照射して粒子検出領域を形成し、この粒子検出領域に含まれる粒子を前記レーザ光によって生じる散乱光を受光して検出する光散乱式粒子検出器において、前記レーザ媒質の取付ブロックに対する取付角度と前記反射鏡の取付ブロックに対する取付角度を調整する取付角度調整手段を設け、この取付角度調整手段が、前記レーザ媒質の取付部材及び前記反射鏡の取付部材の夫々の縁部にねじを切ったねじ孔とねじを切っていない孔を交互に形成すると共に、前記レーザ媒質の取付ブロック及び前記反射鏡の取付ブロックに夫々前記ねじを切っていない孔と中心軸が一致するねじ孔を形成し、前記取付部材のねじを切ったねじ孔へのボルトのねじ込み量と、前記取付部材のねじを切っていない孔へ挿通したボルトの前記取付ブロックへのねじ込み量を調整するものである。
【００１２】
【発明の実施の形態】
以下に本発明の実施の形態を添付図面に基づいて説明する。ここで、図１は本発明に係る光散乱式粒子検出器の概略構成断面図、図２は受光部の概略構成断面図、図３はレーザ媒質取付部材の斜視図、図４は反射鏡取付部材の斜視図、図５はレーザ媒質取付部材の取付角度調整の説明図、図６は他の実施の形態に係る光散乱式粒子検出器の概略構成断面図、図７は反射鏡取付部材の斜視図である。
【００１３】
本発明に係る光散乱式粒子検出器は、図１及び図２に示すように、光源としてのレーザ発振器１と、検出対象となる流体により形成される流路２と、散乱光を受光する受光部３を備えている。レーザ発振器１はともに中空な第１取付ブロック４と第２取付ブロック５で形成されるケース本体６内に収納され、受光部３は第１取付ブロック４の側面に組み付けられた受光ケース７内に収納されている。
【００１４】
レーザ発振器１は、励起用レーザ光Ｌｅを放射する半導体レーザ１１と、励起用レーザ光Ｌｅを集光する集光レンズ１２と、集光レンズ１２で集光した励起用レーザ光Ｌｅを受けて励起し、レーザ光Ｌａを放射するレーザ媒質１３と、レーザ媒質１３と流路２を挟んで対向して設置され、レーザ媒質１３が放射するレーザ光Ｌａを反射してレーザ媒質１３に帰還させる反射鏡１４からなる。
【００１５】
レーザ媒質１３としては、例えばＮｄ：ＹＶＯ₄、Ｎｄ：ＹＡＧなどが用いられる。レーザ媒質１３の集光レンズ１２側の端面には、半導体レーザ１１の励振波長（レーザ媒質１３のポンピング波長）を通す反射防止膜およびレーザ媒質１３の発振波長を反射する反射膜が形成されている。また、レーザ媒質１３の反射鏡１４側の端面には、レーザ媒質１３の発振波長に対する反射防止膜が形成されている。なお、レーザ媒質１３は、その端面から垂直にレーザ光Ｌａを放射する。
【００１６】
流路２は、第１取付ブロック４に形成したインレット８とアウトレット９の間を検出対象となる流体を流すことによって形成される。インレット８とアウトレット９は、流路２が第１取付ブロック４の中心軸と直交または少なくとも交差するように第１取付ブロック４に形成されている。流体は、アウトレット９の下流に接続した吸引ポンプ（不図示）により吸引され、インレット８からアウトレット９に流れる。そして、レーザ光Ｌａと流路２が交差する箇所が粒子検出領域１０となる。
【００１７】
受光部３は、粒子検出領域１０で生じる散乱光Ｌｓを集光する集光レンズ１５と、集光した散乱光Ｌｓを光電変換するフォトダイオード１６と、増幅器１７などを備え、流体に粒子が含まれている場合に粒子検出領域１０において粒子に照射されたレーザ光Ｌａによって生じる散乱光Ｌｓを受光し、散乱光Ｌｓの強度に応じた電気信号を出力する。なお、７ａ，７ｂはＯリングである。
【００１８】
レーザ媒質１３は、図１に示すように、円板状のレーザ媒質取付部材１８を介して第２取付ブロック５に取り付けられている。この時、レーザ媒質１３の光軸１３ａ（レーザ光Ｌａの放射方向）上にあるレーザ媒質１３の出射口は、レーザ媒質取付部材１８の中心軸上にある。また、レーザ媒質取付部材１８の中心軸と第２取付ブロック５の中心軸とは、ほぼ一致した状態になっている。
【００１９】
レーザ媒質取付部材１８は、中心に半導体レーザ１１が放射する励起用レーザ光Ｌｅを通す貫通孔を有し、図３に示すように、円周を６等分した縁部にねじを切ったねじ孔１８ａとねじを切っていない孔１８ｂを交互に形成している。
【００２０】
そして、３つのねじ孔１８ａには、それぞれボルト１９がねじ込まれ、これらのボルト１９の先端部は、図１に示すように、第２取付ブロック５の表面に当接している。また、３つの孔１８ｂには、それぞれボルト１９が挿通され、これらのボルト１９の先端部は第２取付ブロック５に形成されたねじ孔にねじ込まれている。
【００２１】
従って、３つのねじ孔１８ａへの３本のボルト１９のねじ込み量と、３つの孔１８ｂへ挿通したボルト１９の第２取付ブロック５へのねじ込み量を適宜調整すれば、第２取付ブロック５に対してレーザ媒質取付部材１８を自在に傾けて取り付けることができる。これにより、レーザ媒質取付部材１８に取り付けたレーザ媒質１３も第２取付ブロック５に対して傾けることができる。
【００２２】
反射鏡１４は、図１に示すように、反射鏡取付部材２０を介して第１取付ブロック４に取り付けられている。この時、反射鏡１４の光軸１４ａ（レーザ光Ｌａの反射方向）上にある反射面の中心は、反射鏡取付部材２０の中心軸上にある。また、反射鏡取付部材２０の中心軸と第１取付ブロック４の中心軸とは、ほぼ一致した状態になっている。
【００２３】
反射鏡取付部材２０は、図４に示すように、薄肉円筒部材２０ａの両端に大径のフランジ２０ｂと小径のフランジ２０ｃを一体に形成したものである。大径のフランジ２０ｂには、円周を３等分した縁部にねじを切ったねじ孔２０ｄとねじを切っていない孔２０ｅを交互に形成している。
【００２４】
そして、３つのねじ孔２０ｄには、それぞれボルト２１がねじ込まれ、これらのボルト２１の先端部は、図１に示すように、小径のフランジ２０ｃの表面に当接している。また、３つの孔２０ｅには、それぞれボルト２１が挿通され、これらのボルト２１の先端部は小径のフランジ２０ｃに形成されたねじ孔２０ｆにねじ込まれている。
【００２５】
従って、３つのねじ孔２０ｄへの３本のボルト２１のねじ込み量と、３つの孔２０ｅへ挿通したボルト２１のフランジ２０ｃのねじ孔２０ｆへのねじ込み量を適宜調整すれば薄肉円筒部材２０ａが撓むので、第１取付ブロック４に対して反射鏡取付部材２０を自在に傾けて取り付けることができる。これにより、反射鏡取付部材２０に取り付けた反射鏡１４を第１取付ブロック４に対して傾けることができる。
【００２６】
以上のように構成した本発明に係る光散乱式粒子検出器の組付調整について説明する。
先ず、レーザ媒質１３の第２取付ブロック５に対する取付角度の調整を行う。この調整作業は、図５に示すように、調整用のレーザ光Ｌｖを放射するレーザ光源２５と、レーザ光源２５が放射したレーザ光Ｌｖが通過するシャッタ板２６を用意して行う。
【００２７】
そして、取付角度調整治具（不図示）に、第２取付ブロック５にレーザ媒質取付部材１８を介して取り付けたレーザ媒質１３と、レーザ光源２５と、シャッタ板２６をセットする。この時、第２取付ブロック５の面５ａとレーザ光源２５が放射するレーザ光Ｌｖの放射方向とは互いに垂直で、且つ第２取付ブロック５の中心軸とレーザ光Ｌｖの放射方向とは一致するようにセットされている。更に、シャッタ板２６は、その孔２６ａをレーザ光Ｌｖが通過するようにセットされている。
【００２８】
次いで、レーザ光源２５からレーザ光Ｌｖを放射し、レーザ媒質１３の端面で反射した反射光がシャッタ板２６の孔２６ａを通過するように、６本のボルト１９を交互にねじ込みながらレーザ媒質取付部材１８の第２取付ブロック５に対する取付角度を調整する。
【００２９】
反射光がシャッタ板２６の孔２６ａを通過するということは、レーザ媒質１３が第２取付ブロック５の面５ａに対して垂直で、且つ第２取付ブロック５の中心軸と一致する方向にレーザ光Ｌａを放射することを意味する。
従って、レーザ媒質１３の光軸１３ａ（レーザ光Ｌａの放射方向）と第２取付ブロック５の中心軸を一致させることを目的とするレーザ媒質１３の第２取付ブロック５に対する取付角度の調整作業は終了する。
【００３０】
次いで、上記取付角度調整が完了したレーザ媒質１３を取り付けた第２取付ブロック５に、反射鏡取付部材２０を介して反射鏡１４を取り付けた第１取付ブロック４を組み付け、光散乱式粒子検出器の組立を完成する。この時、第１取付ブロック４の中心軸と第２取付ブロック５の中心軸とは、一致した状態にある。
【００３１】
次に、反射鏡１４の第１取付ブロック４に対する取付角度の調整を行う。この調整作業は、組立が完成した光散乱式粒子検出器の流路２に標準粒子を含む気体を流しながら、標準粒子が発する散乱光Ｌｓに応じた受光部３の出力電圧が最大になるように６本のボルト２１を交互にねじ込んで行う。
また、反射鏡１４の透過光量を光パワーメータで見ながら透過光量が最大になるように、６本のボルト２１を交互にねじ込んで反射鏡１４の第１取付ブロック４に対する取付角度の調整を行うこともできる。
【００３２】
散乱光Ｌｓに応じた電圧が最大になるということは、最も効率よくレーザ発振が行われる状態であって、レーザ媒質１３が放射するレーザ光Ｌａの放射方向、即ち
レーザ媒質１３の光軸１３ａと、反射鏡１４の光軸１４ａが一致していることを意味する。
従って、反射鏡１４の光軸１４ａ（レーザ光Ｌａの反射方向）と第１取付ブロック４の中心軸を一致させることを目的とする反射鏡１４の第１取付ブロック４に対する取付角度の調整作業は終了する。
【００３３】
本発明の他の実施の形態に係る光散乱式粒子検出器は、図６に示すように、レーザ媒質取付部材１８と第２取付ブロック５との間にゴム製のＯリング３０を配置した点と、反射鏡取付部材３１を反射鏡取付部材２０と異なる形状に形成した点と、第１取付ブロック４の端部に３つのねじ孔４ａを形成した点と、ねじ孔４ａ等によって反射鏡取付部材３１を固定した点と、反射鏡取付部材３１と第１取付ブロック４との間にゴム製のＯリング３２を配置した点が、図１に示す光散乱式粒子検出器と相違する。なお、図６において、図１と同一符号を付す構成要素については、その説明を省略する。
【００３４】
レーザ媒質取付部材１８と第２取付ブロック５との間に介装されたＯリング３０は、その弾発力によりレーザ媒質取付部材１８と第２取付ブロック５との間を離隔するように作用する。これにより、６本のボルト１９のねじ込み量を調整して行うレーザ媒質取付部材１８の第２取付ブロック５に対する取付角度の調整作業が円滑に行われる。
【００３５】
反射鏡１４は、円板状の反射鏡取付部材３１の中心に取り付けられている。反射鏡取付部材３１は、図７に示すように、円周を６等分した縁部にねじを切ったねじ孔３１ａとねじを切っていない孔３１ｂを交互に形成している。
【００３６】
そして、３つのねじ孔３１ａには、それぞれボルト３３がねじ込まれ、これらのボルト３３の先端部は、図６に示すように、第１取付ブロック４の表面に当接している。また、３つの孔３１ｂには、それぞれボルト３３が挿通され、これらのボルト３３の先端部は第１取付ブロック４に形成されたねじ孔４ａにねじ込まれている。
【００３７】
従って、３つのねじ孔３１ａへの３本のボルト３３のねじ込み量と、３つの孔３１ｂへ挿通したボルト３３の第１取付ブロック４へのねじ込み量を適宜調整すれば、第１取付ブロック４に対し反射鏡取付部材３１を自在に傾けて取り付けることができる。これにより、反射鏡取付部材３１に取り付けた反射鏡１４も第１取付ブロック４に対して傾けることができる。
【００３８】
この時、反射鏡取付部材３１と第１取付ブロック４との間に介装されたＯリング３２は、その弾発力により反射鏡取付部材３１と第１取付ブロック４との間を離隔するように作用する。これにより、６本のボルト３３のねじ込み量を調整して行う反射鏡取付部材３１の第１取付ブロック４に対する取付角度の調整作業が円滑に行われる。
【００３９】
また、図６に示す光散乱式粒子検出器は、レーザ媒質取付部材１８と第２取付ブロック５との間にＯリング３０を介装すると共に、反射鏡取付部材３１と第１取付ブロック４との間にもＯリング３２を介装しているので、第１取付ブロック４と第２取付ブロック５との間にシールを施せば、ケース本体６内の空間は外部と遮断されることになる。これにより、外部の空気などがケース本体６内に侵入することがなく、ケース本体６内に配置されたレーザ媒質１３や反射鏡１４などの光学機器が汚されることがない。
【００４０】
【発明の効果】
以上説明したように請求項１に係る発明によれば、レーザ媒質と反射鏡の取付角度を調整可能としたので、流路や受光部の位置調整が不要となり、組付調整が容易になる。
【００４１】
請求項２に係る発明によれば、レーザ媒質を取付ブロックに対して取付角度調整自在なレーザ媒質取付部材に固定し、反射鏡を取付ブロックに対して取付角度調整自在な反射鏡取付部材に固定したので、レーザ媒質と反射鏡の取付角度の調整が容易になる。
【図面の簡単な説明】
【図１】本発明に係る光散乱式粒子検出器の概略構成断面図
【図２】受光部の概略構成断面図
【図３】レーザ媒質取付部材の斜視図
【図４】反射鏡取付部材の斜視図
【図５】レーザ媒質取付部材の取付角度調整の説明図
【図６】他の実施の形態に係る光散乱式粒子検出器の概略構成断面図
【図７】他の実施の形態に係る光散乱式粒子検出器の反射鏡取付部材の斜視図
【図８】従来の光散乱式粒子検出器の概略構成断面図
【符号の説明】
１…レーザ発振器、２…流路、３…受光部、４…第１取付ブロック、５…第２取付ブロック、６…ケース本体、８…インレット、９…アウトレット、１０…粒子検出領域、１１…半導体レーザ、１２…集光レンズ、１３…レーザ媒質、１３ａ…レーザ媒質の光軸、１４…反射鏡、１４ａ…反射鏡の光軸、１８…レーザ媒質取付部材、４ａ，１８ａ，２０ｄ，２０ｆ、３１ａ…ねじ孔、１８ｂ，２０ｅ，３１ｂ…孔、１９，２１，３３…ボルト、２０，３１…反射鏡取付部材、３０，３２…Ｏリング、Ｌａ…レーザ光、Ｌｅ…励起用レーザ光、Ｌｓ…散乱光。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a light scattering type particle detector that detects particles contained in a sample fluid using a laser oscillator using a laser medium as a light source.
[0002]
[Prior art]
As a conventional light scattering type particle detector, as shown in FIG. 8, a flow path 107 is formed between a laser medium 105 constituting a laser oscillator and a reflecting mirror 106 by a fluid to be detected by a particle, and a semiconductor laser 108 is formed. The excitation light Le is condensed on the laser medium 105 by the condensing lens 109 to excite the laser medium 105, and a portion where the laser beam La resonating between the laser medium 105 and the reflecting mirror 106 intersects the flow path 107 is shown. As the particle detection region 110, scattered light generated in the particle detection region 110 by the resonating laser light La is received by a light receiving unit (not shown), and particles contained in the sample fluid are detected from an electrical signal corresponding to the intensity of the scattered light. What is to be detected is known.
[0003]
Reference numeral 112 denotes a hollow first mounting block, and 113 denotes a hollow second mounting block. The first mounting block 112 and the second mounting block 113 form a case main body. The laser medium 105 is directly assembled to the second mounting block 113, and the second mounting block 113 is assembled to the first mounting block 112. A light receiving case (not shown) that houses the light receiving portion is assembled to the side surface of the first mounting block 112.
[0004]
When the laser medium 105 is assembled to the second mounting block 113, the laser beam La emitted by the laser medium 105 is perpendicular to the end face (radiation surface) of the laser medium 105 if there is no assembly error or the like. And proceed in a direction that coincides with the central axis of the first mounting block 112.
[0005]
[Problems to be solved by the invention]
However, in actuality, due to an assembly error or the like, the laser light La does not come out in a direction that coincides with the central axis of the first mounting block 112. In this case, it is necessary to ensure that the laser beam La reflected by the reflecting mirror 106 returns to the laser medium 105 by adjusting the mounting angle of the reflecting mirror 106 with respect to the first mounting block 112.
[0006]
Further, even if the reflecting mirror 106 is adjusted to an optimum mounting angle so that the laser light La reflected by the reflecting mirror 106 is surely returned to the laser medium 105, the radiation direction of the oscillated laser light La is the first mounting block 112. Therefore, it may be necessary to shift the flow path 107 arranged on the assumption that they coincide with each other. If the flow path 107 is shifted, the position of the particle detection region 110 also changes, and accordingly, the mounting position of the light receiving case that houses the light receiving portion to the first mounting block 112 must be adjusted.
[0007]
Therefore, in the conventional light scattering type particle detector, the position adjustment of the flow path 107 and the attachment of the light receiving case to the first attachment block 112 are performed in accordance with the attachment angle adjustment of the reflecting mirror 106 performed when there is an assembly error or the like. This is a problem because it requires complicated adjustment for adjustment and requires a lot of man-hours during assembly work of the entire apparatus.
[0008]
The present invention has been made in view of such problems of the prior art, and an object of the present invention is to provide a scattering type particle detector that allows easy adjustment of the assembly angle of a laser medium, a reflecting mirror, and the like. It is something to be offered.
[0009]
[Means for Solving the Problems]
In order to solve the above problem, the invention according to claim 1 is configured such that a flow path formed by a sample fluid is disposed between a laser medium excited by excitation light and a reflecting mirror that reflects the laser light emitted from the laser medium. In the light scattering type particle detector that irradiates the laser beam to the flow path to form a particle detection region, and receives and detects the scattered light generated by the laser light in the particle detection region, An attachment angle adjusting means for adjusting an attachment angle of the laser medium with respect to the attachment block and an attachment angle of the reflector with respect to the attachment block is provided , and the attachment angle adjustment means of the laser medium is screwed to an edge of the attachment member of the laser medium. A screw hole in which a center axis coincides with the non-threaded hole is formed in the mounting block of the laser medium. And, a screwing amount of the bolt into the screw hole threaded in the mounting member, and adjusts the amount of screwing into the mounting block bolts inserted through the holes that is not threaded in the mounting member.
[0010]
In the invention according to claim 2, the flow path formed by the sample fluid is disposed between the laser medium excited by the excitation light and the reflecting mirror that reflects the laser light emitted from the laser medium. In the light scattering type particle detector that forms a particle detection region by irradiating the laser beam and receives and detects the scattered light generated by the laser beam in the particle detection region, the laser medium mounting block Mounting angle adjusting means for adjusting the mounting angle with respect to the reflecting mirror and the mounting angle of the reflecting mirror with respect to the mounting block of the reflecting mirror is provided , and the mounting angle adjusting means is screwed to the respective edge portions of the laser medium mounting member and the reflecting mirror mounting member. The screw holes that are cut and the holes that are not cut are alternately formed, and the screws are not cut in the laser medium mounting block and the reflector mounting block, respectively. And a screw hole in which the center axis coincides with the screw hole of the mounting member into the screw hole into which the screw is cut, and a bolt inserted into the screw hole in the mounting member that is not cut into the mounting block. The screwing amount is adjusted .
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is a schematic sectional view of a light scattering type particle detector according to the present invention, FIG. 2 is a schematic sectional view of a light receiving unit, FIG. 3 is a perspective view of a laser medium mounting member, and FIG. FIG. 5 is an explanatory view of adjusting the mounting angle of the laser medium mounting member, FIG. 6 is a schematic sectional view of a light scattering particle detector according to another embodiment, and FIG. It is a perspective view.
[0013]
As shown in FIGS. 1 and 2, the light scattering type particle detector according to the present invention includes a laser oscillator 1 as a light source, a flow path 2 formed by a fluid to be detected, and a light reception for receiving scattered light. Part 3 is provided. The laser oscillator 1 is housed in a case body 6 formed by a hollow first mounting block 4 and a second mounting block 5, and the light receiving unit 3 is housed in a light receiving case 7 assembled on the side surface of the first mounting block 4. It is stored.
[0014]
The laser oscillator 1 is excited by receiving a semiconductor laser 11 that emits an excitation laser beam Le, a condenser lens 12 that collects the excitation laser beam Le, and an excitation laser beam Le that is collected by the condenser lens 12. The laser medium 13 that emits the laser light La, and the reflecting mirror that is disposed opposite to the laser medium 13 with the flow path 2 interposed therebetween, reflects the laser light La emitted by the laser medium 13 and returns it to the laser medium 13. 14
[0015]
As the laser medium 13, for example, Nd: YVO ₄ , Nd: YAG or the like is used. On the end surface of the laser medium 13 on the condenser lens 12 side, an antireflection film that passes the excitation wavelength of the semiconductor laser 11 (pumping wavelength of the laser medium 13) and a reflection film that reflects the oscillation wavelength of the laser medium 13 are formed. . An antireflection film for the oscillation wavelength of the laser medium 13 is formed on the end face of the laser medium 13 on the reflecting mirror 14 side. The laser medium 13 emits laser light La vertically from its end face.
[0016]
The flow path 2 is formed by flowing a fluid to be detected between the inlet 8 and the outlet 9 formed in the first mounting block 4. The inlet 8 and the outlet 9 are formed in the first mounting block 4 so that the flow path 2 is orthogonal or at least intersects with the central axis of the first mounting block 4. The fluid is sucked by a suction pump (not shown) connected downstream of the outlet 9 and flows from the inlet 8 to the outlet 9. A location where the laser beam La and the flow path 2 intersect becomes the particle detection region 10.
[0017]
The light receiving unit 3 includes a condensing lens 15 that condenses the scattered light Ls generated in the particle detection region 10, a photodiode 16 that photoelectrically converts the collected scattered light Ls, an amplifier 17, and the like, and particles are included in the fluid. In this case, the scattered light Ls generated by the laser light La applied to the particles in the particle detection region 10 is received, and an electric signal corresponding to the intensity of the scattered light Ls is output. 7a and 7b are O-rings.
[0018]
As shown in FIG. 1, the laser medium 13 is attached to the second attachment block 5 via a disk-like laser medium attachment member 18. At this time, the exit of the laser medium 13 on the optical axis 13 a of the laser medium 13 (radiation direction of the laser light La) is on the central axis of the laser medium mounting member 18. Further, the central axis of the laser medium mounting member 18 and the central axis of the second mounting block 5 are substantially coincident with each other.
[0019]
The laser medium mounting member 18 has a through-hole through which the excitation laser beam Le emitted from the semiconductor laser 11 passes in the center, and a screw having a thread cut at an edge portion obtained by dividing the circumference into six equal parts as shown in FIG. Holes 18a and holes 18b that are not threaded are alternately formed.
[0020]
Bolts 19 are respectively screwed into the three screw holes 18a, and the tip portions of these bolts 19 are in contact with the surface of the second mounting block 5 as shown in FIG. Bolts 19 are respectively inserted into the three holes 18 b, and the tip portions of these bolts 19 are screwed into screw holes formed in the second mounting block 5.
[0021]
Therefore, if the screwing amount of the three bolts 19 into the three screw holes 18a and the screwing amount of the bolts 19 inserted into the three holes 18b into the second mounting block 5 are appropriately adjusted, the second mounting block 5 On the other hand, the laser medium mounting member 18 can be freely tilted and mounted. Thereby, the laser medium 13 attached to the laser medium attachment member 18 can also be inclined with respect to the second attachment block 5.
[0022]
As shown in FIG. 1, the reflecting mirror 14 is attached to the first mounting block 4 via a reflecting mirror mounting member 20. At this time, the center of the reflecting surface on the optical axis 14 a of the reflecting mirror 14 (the reflection direction of the laser light La) is on the central axis of the reflecting mirror mounting member 20. Further, the central axis of the reflecting mirror mounting member 20 and the central axis of the first mounting block 4 are substantially coincident with each other.
[0023]
As shown in FIG. 4, the reflecting mirror mounting member 20 is formed by integrally forming a large-diameter flange 20b and a small-diameter flange 20c at both ends of a thin cylindrical member 20a. The large-diameter flange 20b is alternately formed with screw holes 20d that are threaded and edges 20e that are not threaded at the edge of the circumference divided into three equal parts.
[0024]
Bolts 21 are respectively screwed into the three screw holes 20d, and the tip portions of these bolts 21 are in contact with the surface of the small-diameter flange 20c as shown in FIG. Bolts 21 are inserted into the three holes 20e, respectively, and the tip portions of these bolts 21 are screwed into screw holes 20f formed in the small-diameter flange 20c.
[0025]
Accordingly, if the screwing amount of the three bolts 21 into the three screw holes 20d and the screwing amount of the bolts 21 inserted into the three holes 20e into the screw holes 20f of the flange 20c are appropriately adjusted, the thin cylindrical member 20a is bent. Therefore, the reflector mounting member 20 can be freely tilted and attached to the first mounting block 4. Thereby, the reflecting mirror 14 attached to the reflecting mirror attachment member 20 can be tilted with respect to the first attachment block 4.
[0026]
Assembly adjustment of the light scattering particle detector according to the present invention configured as described above will be described.
First, the attachment angle of the laser medium 13 with respect to the second attachment block 5 is adjusted. As shown in FIG. 5, this adjustment operation is performed by preparing a laser light source 25 that emits the adjustment laser light Lv and a shutter plate 26 through which the laser light Lv emitted by the laser light source 25 passes.
[0027]
Then, the laser medium 13 attached to the second attachment block 5 via the laser medium attachment member 18, the laser light source 25, and the shutter plate 26 are set on an attachment angle adjusting jig (not shown). At this time, the surface 5a of the second mounting block 5 and the radiation direction of the laser light Lv emitted from the laser light source 25 are perpendicular to each other, and the central axis of the second mounting block 5 coincides with the radiation direction of the laser light Lv. It is set like so. Further, the shutter plate 26 is set so that the laser light Lv passes through the hole 26a.
[0028]
Next, the laser medium mounting member is alternately screwed in with the six bolts 19 so that the reflected light reflected from the end face of the laser medium 13 is emitted from the laser light source 25 and reflected by the end face of the laser medium 13. The mounting angle with respect to the second mounting block 18 is adjusted.
[0029]
The fact that the reflected light passes through the hole 26a of the shutter plate 26 means that the laser medium 13 is in the direction perpendicular to the surface 5a of the second mounting block 5 and coincides with the central axis of the second mounting block 5. It means to emit La.
Therefore, the adjustment operation of the mounting angle of the laser medium 13 with respect to the second mounting block 5 for the purpose of making the optical axis 13a of the laser medium 13 (radiation direction of the laser light La) coincide with the central axis of the second mounting block 5 is performed. finish.
[0030]
Next, the first mounting block 4 to which the reflecting mirror 14 is mounted via the reflecting mirror mounting member 20 is assembled to the second mounting block 5 to which the laser medium 13 whose mounting angle adjustment has been completed is mounted, and a light scattering particle detector. Complete the assembly. At this time, the central axis of the first mounting block 4 and the central axis of the second mounting block 5 are in agreement.
[0031]
Next, the attachment angle of the reflecting mirror 14 with respect to the first attachment block 4 is adjusted. This adjustment operation is performed so that the output voltage of the light receiving unit 3 is maximized according to the scattered light Ls emitted from the standard particles while flowing the gas containing the standard particles through the flow path 2 of the light scattering particle detector that has been assembled. 6 bolts 21 are screwed alternately.
In addition, the mounting angle of the reflecting mirror 14 with respect to the first mounting block 4 is adjusted by alternately screwing the six bolts 21 so that the transmitted light quantity of the reflecting mirror 14 is maximized while viewing the light quantity with the optical power meter. You can also.
[0032]
The maximum voltage according to the scattered light Ls means that laser oscillation is most efficiently performed, and the radiation direction of the laser light La emitted by the laser medium 13, that is, the optical axis 13a of the laser medium 13 and This means that the optical axis 14a of the reflecting mirror 14 is coincident.
Therefore, the adjustment operation of the mounting angle of the reflecting mirror 14 with respect to the first mounting block 4 for the purpose of making the optical axis 14a of the reflecting mirror 14 (the reflection direction of the laser beam La) coincide with the central axis of the first mounting block 4 is performed. finish.
[0033]
In the light scattering particle detector according to another embodiment of the present invention, a rubber O-ring 30 is disposed between the laser medium mounting member 18 and the second mounting block 5, as shown in FIG. The reflector mounting member 31 is formed in a shape different from that of the reflector mounting member 20, the point where three screw holes 4a are formed at the end of the first mounting block 4, the screw hole 4a, etc. The point which fixed the member 31 and the point which has arrange | positioned the rubber-made O-ring 32 between the reflective-mirror attachment member 31 and the 1st attachment block 4 differ from the light-scattering type particle detector shown in FIG. In FIG. 6, the description of the components having the same reference numerals as those in FIG. 1 is omitted.
[0034]
The O-ring 30 interposed between the laser medium mounting member 18 and the second mounting block 5 acts so as to separate the laser medium mounting member 18 and the second mounting block 5 by its elastic force. . Thereby, the adjustment operation | work of the attachment angle with respect to the 2nd attachment block 5 of the laser medium attachment member 18 performed by adjusting the screwing amount of the six volt | bolts 19 is performed smoothly.
[0035]
The reflecting mirror 14 is attached to the center of a disc-like reflecting mirror mounting member 31. As shown in FIG. 7, the reflecting mirror mounting member 31 is formed alternately with screw holes 31 a that are threaded and edges 31 b that are not threaded at the edge portion of the circumference divided into six equal parts.
[0036]
Bolts 33 are respectively screwed into the three screw holes 31a, and the tip portions of these bolts 33 are in contact with the surface of the first mounting block 4 as shown in FIG. Bolts 33 are respectively inserted into the three holes 31 b, and tip portions of these bolts 33 are screwed into screw holes 4 a formed in the first mounting block 4.
[0037]
Therefore, if the screwing amount of the three bolts 33 into the three screw holes 31a and the screwing amount of the bolts 33 inserted into the three holes 31b into the first mounting block 4 are appropriately adjusted, the first mounting block 4 On the other hand, the reflector mounting member 31 can be freely tilted and attached. Thereby, the reflecting mirror 14 attached to the reflecting mirror attachment member 31 can also be inclined with respect to the first attachment block 4.
[0038]
At this time, the O-ring 32 interposed between the reflecting mirror mounting member 31 and the first mounting block 4 is separated from the reflecting mirror mounting member 31 and the first mounting block 4 by its elastic force. Act on. Thereby, the adjustment operation | work of the attachment angle with respect to the 1st attachment block 4 of the reflective mirror attachment member 31 performed by adjusting the screwing amount of the six volt | bolts 33 is performed smoothly.
[0039]
The light scattering type particle detector shown in FIG. 6 has an O-ring 30 interposed between the laser medium mounting member 18 and the second mounting block 5, and the reflecting mirror mounting member 31 and the first mounting block 4. Since the O-ring 32 is interposed between the first mounting block 4 and the second mounting block 5, the space in the case body 6 is blocked from the outside. . Thereby, external air etc. do not penetrate | invade in the case main body 6, and optical instruments, such as the laser medium 13 and the reflective mirror 14 which are arrange | positioned in the case main body 6, are not polluted.
[0040]
【The invention's effect】
As described above, according to the first aspect of the present invention, the mounting angle between the laser medium and the reflecting mirror can be adjusted, so that the position adjustment of the flow path and the light receiving unit is unnecessary, and the assembly adjustment is facilitated.
[0041]
According to the invention of claim 2, the laser medium is fixed to the laser medium mounting member whose mounting angle is adjustable with respect to the mounting block, and the reflecting mirror is fixed to the reflecting mirror mounting member whose mounting angle is adjustable with respect to the mounting block. Therefore, the adjustment of the mounting angle between the laser medium and the reflecting mirror becomes easy.
[Brief description of the drawings]
1 is a schematic cross-sectional view of a light scattering particle detector according to the present invention. FIG. 2 is a schematic cross-sectional view of a light receiving unit. FIG. 3 is a perspective view of a laser medium mounting member. FIG. 5 is an explanatory view of adjusting the mounting angle of a laser medium mounting member. FIG. 6 is a schematic cross-sectional view of a light scattering particle detector according to another embodiment. FIG. 7 is according to another embodiment. FIG. 8 is a perspective view of a reflector mounting member of a light scattering particle detector. FIG. 8 is a schematic sectional view of a conventional light scattering particle detector.
DESCRIPTION OF SYMBOLS 1 ... Laser oscillator, 2 ... Flow path, 3 ... Light-receiving part, 4 ... 1st attachment block, 5 ... 2nd attachment block, 6 ... Case main body, 8 ... Inlet, 9 ... Outlet, 10 ... Particle detection area | region, 11 ... Semiconductor laser, 12 ... Condensing lens, 13 ... Laser medium, 13a ... Optical axis of laser medium, 14 ... Reflector, 14a ... Optical axis of reflector, 18 ... Laser medium mounting member, 4a, 18a, 20d, 20f, 31a ... Screw hole, 18b, 20e, 31b ... Hole, 19, 21, 33 ... Bolt, 20, 31 ... Reflecting mirror mounting member, 30, 32 ... O-ring, La ... Laser light, Le ... Excitation laser light, Ls ... scattered light.

Claims

A flow path formed by the sample fluid is disposed between a laser medium excited by the excitation light and a reflecting mirror that reflects the laser light emitted from the laser medium, and the laser light is irradiated onto the flow path to form particles. In a light scattering type particle detector that forms a detection region and detects particles contained in the particle detection region by receiving scattered light generated by the laser light, the mounting angle of the laser medium with respect to the mounting block and the reflection mirror A mounting angle adjusting means for adjusting a mounting angle with respect to the mounting block is provided , and the laser medium mounting angle adjusting means alternates between a screw hole and a non-threaded hole at the edge of the laser medium mounting member. And forming a screw hole whose center axis coincides with the hole that is not threaded in the mounting block of the laser medium, and connecting the threaded hole of the mounting member to the threaded hole. Screwing amount of belt and the light scattering particle detector, characterized in that adjusting the amount of screwing into the mounting block bolts inserted through the holes that is not threaded in the mounting member.

A flow path formed by the sample fluid is disposed between a laser medium excited by the excitation light and a reflecting mirror that reflects the laser light emitted from the laser medium, and the laser light is irradiated onto the flow path to form particles. In a light scattering type particle detector that forms a detection region and detects particles contained in the particle detection region by receiving scattered light generated by the laser light, the mounting angle of the laser medium with respect to the mounting block and the reflection mirror A mounting angle adjusting means for adjusting a mounting angle with respect to the mounting block is provided , and the mounting angle adjusting means includes a screw hole and a screw that are threaded at respective edges of the laser medium mounting member and the reflecting mirror mounting member. Holes that are not cut are alternately formed, and the center axis coincides with the holes that are not threaded in the laser medium mounting block and the reflector mounting block, respectively. Hole is formed, and screwing amount of the bolt into the screw hole threaded in the mounting member, the adjusting the screwing amount into the mounting block bolts inserted through the holes that is not threaded in the mounting member A light scattering particle detector.